To see the other types of publications on this topic, follow the link: CHLS.
Journal articles on the topic 'CHLS'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'CHLS.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Kong, Bo, Bing He, Huan Yu, and Yu Liu. "An Integrated Field and Hyperspectral Remote Sensing Method for the Estimation of Pigments Content of Stipa Purpurea in Shenzha, Tibet." Mathematical Problems in Engineering 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/4787054.
Full textAbstract:
Stipa purpurea is the representative type of alpine grassland in Tibet and the surviving and development material for herdsmen. This paper takes Shenzha County as the research area. Based on the analysis of typical hyperspectral variables sensitive to chlorophyll content of Stipa purpurea, 10 spectral variables with significant correlation with chlorophyll were extracted. The estimation model of chlorophyll was established. The photosynthetic pigment contents in the Shenzha area were calculated by using HJ-1A remote sensing images. The results show that (1) there are significant correlations between chlorophyll content and spectral variables; in particular, the coefficient of Chlb in Stipa purpurea with RVI is the largest (0.728); (2) 10 variables are correlated with chlorophyll, and the order of correlation is Chlb > Chla > Chls; (3) for the estimation of Chla, the EVI is the best variable. RVI, NDVI, and VI2 are suitable for Chlb; RVI and NDVI are also suitable for the estimation of Chls; (4) the mean estimated content of Chla in Stipa bungeana is about 4.88 times that of Chlb, while Cars is slightly more than Chlb; (5) the distribution of Chla is opposite to Chlb and Chls content in water area.
2
Lin, C., S. C. Popescu, S. C. Huang, Y. C. Chen, P. T. Chang, and H. L. Wen. "A novel reflectance-based model for evaluating chlorophyll concentration of fresh and water-stressed leaves." Biogeosciences Discussions 10, no. 11 (2013): 17893–937. http://dx.doi.org/10.5194/bgd-10-17893-2013.
Full textAbstract:
Abstract. Water deficit can cause chlorophyll degradation which decreases foliar chlorophyll concentration (Chls). Few studies investigated the effectiveness of spectral indices under water stress conditions. Chlorophyll meters have been extensively used for a wide variety of leaf chlorophyll and nitrogen estimations. Since a chlorophyll meter works based on the sensing of leaves absorptance and transmittance, the reading of chlorophyll concentration will be affected by changes in transmittance as if there is a water deficit in leaves. The overall objective of this paper was to develop a novel and reliable reflectance-based model for estimating Chls of fresh and water stressed leaves using the reflectance at the absorption bands of chlorophyll a and b and the red edge spectrum. Three independent experiments were designed to collect data from three leaf sample sets for the construction and validation of Chls estimation models. First, a reflectance experiment was conducted to collect foliar Chls and reflectance of leaves with varying water stress using the ASD FieldSpec spectroradiometer. Second, a chlorophyll meter (SPAD-502) experiment was carried out to collect foliar Chls and meter reading. These two datasets were separately used for developing reflectance-based or absorptance-based Chls estimation models using linear and nonlinear regression analysis. Suitable models were suggested mainly based on the coefficient of determination (R2). Finally, an experiment was conducted to collect the third dataset for the validation of Chls models using the root mean squared error (RMSE) and the mean absolute error (MAE). In all of the experiments, the observations (real values) of the foliar Chls were extracted from acetone solution and determined by using a Hitachi U-2000 spectrophotometer. The spectral indices in the form of reflectance ratio/difference/slope derived from the chlb absorption bands (ρ645 and ρ455) provided Chls estimates with RMSE around 0.40–0.55 mg g–1 for both fresh and water-stressed samples. We improved Chls prediction accuracy by incorporating the reflectance at red edge position (ρREP) in regression models. An effective chlorophyll indicator with the form of (ρ645–ρ455) / ρREP proved to be the most accurate and stable predictor for foliar Chls concentration. This model was derived with an R2 of 0.90 (P < 0.01) from the training samples and evaluated with RMSE 0.35 and 0.38 mg g–1 for the validation samples of fresh and water stressed leaves, respectively. The average prediction error was within 14% of the mean absolute error.
3
JENSEN, Poul E., James D. REID, and C. Neil HUNTER. "Modification of cysteine residues in the ChlI and ChlH subunits of magnesium chelatase results in enzyme inactivation." Biochemical Journal 352, no. 2 (2000): 435–41. http://dx.doi.org/10.1042/bj3520435.
Full textAbstract:
The enzyme magnesium protoporphyrin chelatase catalyses the insertion of magnesium into protoporphyrin, the first committed step in chlorophyll biosynthesis. Magnesium chelatase from the cyanobacterium Synechocystis PCC6803 has been reconstituted in a highly active state as a result of purifying the constituent proteins from strains of Escherichia coli that overproduce the ChlH, ChlI and ChlD subunits. These individual subunits were analysed for their sensitivity to N-ethylmaleimide (NEM), in order to assess the roles that cysteine residues play in the partial reactions that comprise the catalytic cycle of Mg2+ chelatase, such as the ATPase activity of ChlI, and the formation of ChlI–ChlD–MgATP and ChlH–protoporphyrin complexes. It was shown that NEM binds to ChlI and inhibits the ATPase activity of this subunit, and that prior incubation with MgATP affords protection against inhibition. Quantitative analysis of the effects of NEM binding on ChlI-catalysed ATPase activity showed that three out of four thiols per ChlI molecule are available to react with NEM, but only one cysteine residue per ChlI subunit is essential for ATPase activity. In contrast, the cysteines in ChlD are not essential for Mg2+ chelatase activity, and the formation of the ChlI–ChlD–ATP complex can proceed with NEM-treated ChlI. Neither the ATPase activity of ChlI nor NEM-modifiable cysteines are therefore required to form the ChlI–ChlD–MgATP complex. However, this complex cannot catalyse magnesium chelation in the presence of the ChlH subunit, protoporphyrin and Mg2+ ions. The simplest explanation for this is that in an intact Mg2+ chelatase complex the ATPase activity of ChlI drives the chelation process. NEM binds to ChlH and inhibits the chelation reaction, and this effect can be partially alleviated by pre-incubating ChlH with magnesium and ATP. We conclude that cysteine residues play an important role in the chelation reaction, in respect of the ChlI–MgATP association, ATP hydrolysis and in the interaction of ChlH with MgATP and protoporphyrin IX.
4
JENSEN, Poul E., Lucien C. D. GIBSON, and C. Neil HUNTER. "Determinants of catalytic activity with the use of purified I, D and H subunits of the magnesium protoporphyrin IX chelatase from Synechocystis PCC68031." Biochemical Journal 334, no. 2 (1998): 335–44. http://dx.doi.org/10.1042/bj3340335.
Full textAbstract:
The I, D and H subunits (ChlI, ChlD and ChlH respectively) of the magnesium protoporphyrin IX chelatase from Synechocystis have been purified to homogeneity as a result of the overexpression of the encoding genes in Escherichia coli and the production of large quantities of histidine-tagged proteins. These subunits have been used in an initial investigation of the biochemical and kinetic properties of the enzyme. The availability of pure ChlI, ChlD and ChlH has allowed us to estimate the relative concentrations of the three protein components required for optimal activity, and to investigate the dependence of chelatase activity on the concentrations of MgCl2, ATP and protoporphyrin IX. It was found that, whereas ChlD and ChlH are likely to be monomeric, ChlI can aggregate in an ATP-dependent manner, changing from a dimeric to an octameric structure. Subunit titration assays suggest an optimal ratio of ChlI, ChlD and ChlH of 2:1:4 respectively. However, the dependence of chelatase activity on increasing concentrations of ChlI and ChlH with respect to ChlD suggests that these two subunits, at least in vitro, behave as substrates in their interaction with ChlD. Mg chelation could not be detected unless the Mg2+ concentration exceeded the ATP concentration, suggesting at least two requirements for Mg2+, one as a component of MgATP2-, the other as the chelated metal. The steady-state kinetic parameters were determined from continuous assays; the Km values for protoporphyrin, MgCl2 and ATP were 1.25 µM, 4.9 mM and 0.49 mM respectively. The rate dependence of Mg2+ was clearly sigmoidal with a Hill coefficient of 3, suggesting positive co-operativity. Initiating the reaction by the addition of one of the substrates in these continuous assays resulted in a significant lag period of at least 10 min before the linear production of Mg protoporphyrin. This lag was significantly decreased by preincubating ChlI and ChlD with ATP and MgCl2, and by mixing it with ChlH that had been preincubated with protoporphyrin IX, ATP and MgCl2. This suggests not only a close MgATP2--dependent interaction between ChlI and ChlD but also an interaction between ChlH and the protoporphyrin substrate that also is stimulated by ATP and MgCl2.
5
Farmer, David A., Amanda A. Brindley, Andrew Hitchcock, et al. "The ChlD subunit links the motor and porphyrin binding subunits of magnesium chelatase." Biochemical Journal 476, no. 13 (2019): 1875–87. http://dx.doi.org/10.1042/bcj20190095.
Full textAbstract:
Abstract Magnesium chelatase initiates chlorophyll biosynthesis, catalysing the MgATP2−-dependent insertion of a Mg2+ ion into protoporphyrin IX. The catalytic core of this large enzyme complex consists of three subunits: Bch/ChlI, Bch/ChlD and Bch/ChlH (in bacteriochlorophyll and chlorophyll producing species, respectively). The D and I subunits are members of the AAA+ (ATPases associated with various cellular activities) superfamily of enzymes, and they form a complex that binds to H, the site of metal ion insertion. In order to investigate the physical coupling between ChlID and ChlH in vivo and in vitro, ChlD was FLAG-tagged in the cyanobacterium Synechocystis sp. PCC 6803 and co-immunoprecipitation experiments showed interactions with both ChlI and ChlH. Co-production of recombinant ChlD and ChlH in Escherichia coli yielded a ChlDH complex. Quantitative analysis using microscale thermophoresis showed magnesium-dependent binding (Kd 331 ± 58 nM) between ChlD and H. The physical basis for a ChlD–H interaction was investigated using chemical cross-linking coupled with mass spectrometry (XL–MS), together with modifications that either truncate ChlD or modify single residues. We found that the C-terminal integrin I domain of ChlD governs association with ChlH, the Mg2+ dependence of which also mediates the cooperative response of the Synechocystis chelatase to magnesium. The interaction site between the AAA+ motor and the chelatase domain of magnesium chelatase will be essential for understanding how free energy from the hydrolysis of ATP on the AAA+ ChlI subunit is transmitted via the bridging subunit ChlD to the active site on ChlH.
6
Paciocco, Adua Elizabeth. "Chinese maintenance and shift among Chinese migrant youth in Prato (Italy) and its connectedness with new formations of Chinese identity." Global Chinese 7, no. 1 (2021): 29–55. http://dx.doi.org/10.1515/glochi-2021-0002.
Full textAbstract:
Abstract In view of theory sustaining that there is a nexus between linguistic repertoire, language and social identity, and that habitual language choice is not haphazard, this study explores the habitual use of Chinese – hence Chinese language maintenance (CHLM) – among multilingual Chinese migrant youth in Prato (Italy) to understand the social meaning embedded in it. The youth are multilingual; they speak Chinese and Italian. They exhibit CHLM with parents, as parents are not competent speakers of Italian. Some of the youth who are speakers of Italian, speak Chinese with peers, hence exhibiting CHLM within their generational cohort; while others do not, hence exhibiting Chinese language shift (CHLS). Oral data in which the youth self-present, report on others with whom they share social space, and talk about CHLM indicate that youth who speak Chinese with peers are not integrated into mainstream society; conversely, youth who are integrated shift to speaking Italian with peers. The analysis evidences that the youth’s integration is influenced by their social identity formation and other variables; such as their migration history, Chinese demographics in Prato and language ideology. Further, this study reveals that the youth are characterised by heterogeneity and that it is hierarchically ordered, heterogeneity and hierarchical ordering being indexed by the youth’s CHLM/CHLS and their alignment/disalignment with others that feature in their social space. This finding evidences that different enactments of Chinese identity are developing among Chinese migrant youth in Prato, thus de-essentialising Chinese identity. This study is wide reaching since it contributes to research on CHLM, the social identity formation of Chinese migrant youth populations, as well as new forms of Chinese identity emerging outside of the PRC. Data was analysed using the talk-in-interaction method of narrative analysis that studies oral narratives in which tellers seek to make sense of their human experience.
7
Sawicki, Artur, Shuaixiang Zhou, Kathrin Kwiatkowski, Meizhong Luo, and Robert D. Willows. "1-N-histidine phosphorylation of ChlD by the AAA+ ChlI2 stimulates magnesium chelatase activity in chlorophyll synthesis." Biochemical Journal 474, no. 12 (2017): 2095–105. http://dx.doi.org/10.1042/bcj20161094.
Full textAbstract:
Magnesium chelatase (Mg-chelatase) inserts magnesium into protoporphyrin during the biosynthesis of chlorophyll and bacteriochlorophyll. Enzyme activity is reconstituted by forming two separate preactivated complexes consisting of a GUN4/ChlH/protoporphyrin IX substrate complex and a ChlI/ChlD enzyme ‘motor’ complex. Formation of the ChlI/ChlD complex in both Chlamydomonas reinhardtii and Oryza sativa is accompanied by phosphorylation of ChlD by ChlI, but the orthologous protein complex from Rhodobacter capsulatus, BchI/BchD, gives no detectable phosphorylation of BchD. Phosphorylation produces a 1-N-phospho-histidine within ChlD. Proteomic analysis indicates that phosphorylation occurs at a conserved His residue in the C-terminal integrin I domain of ChlD. Comparative analysis of the ChlD phosphorylation with enzyme activities of various ChlI/ChlD complexes correlates the phosphorylation by ChlI2 with stimulation of Mg-chelatase activity. Mutation of the H641 of CrChlD to E641 prevents both phosphorylation and stimulation of Mg-chelatase activity, confirming that phosphorylation at H641 stimulates Mg-chelatase. The properties of ChlI2 compared with ChlI1 of Chlamydomonas and with ChlI of Oryza, shows that ChlI2 has a regulatory role in Chlamydomonas.
8
Shin, Ji Hye, and Peggy Albers. "An Analysis of the Effect of a Cyber Home Learning System on Korean Secondary School Students’ English Language Achievement and Attitude." TESL Canada Journal 32, no. 2 (2015): 45. http://dx.doi.org/10.18806/tesl.v32i2.1207.
Full textAbstract:
This study examined the effectiveness of a Cyber Home Learning System (CHLS), an online learning system currently being employed in South Korea to improve the access and quality of public education as well as to reduce pri- vate tutoring expenditures. The quasi-experimental research design used ex- periment and survey methods to learn about the impact of CHLS on student performance and to ascertain students’ perceptions of the system. The results of the experiment indicated that no statistically significant differences in test performance existed between the experimental and control groups. This finding suggested that CHLS did not have an impact on student performance overall. However, after the data were disaggregated according to ability level, students in the advanced level showed statistically significant differences between the ex- perimental and control groups. Results from the survey indicated that the CHLS was particularly effective for those who are motivated to voluntarily participate in academic activities and who have the capability for self-initiated study. The CHLS can be considered a useful supplement but not a replacement for second- ary private tutoring. To better address the needs of other learners, the English content of CHLS may need to be further modified to match students’ varying proficiency levels and learning styles. Cette étude a porté sur l’efficacité d’un système d’apprentissage en ligne, Cyber Home Learning System – CHLS, actuellement employé en Corée du Sud pour améliorer la qualité de l’éducation publique, en augmenter l’accessibilité, et ré- duire les frais liés aux services de tutorat privé. Le plan de recherche quasi-expé- rimental s’est appuyé sur l’expérimentation et des méthodes d’enquête pour en apprendre sur l’impact du CHLS sur le rendement des élèves et pour confirmer les perceptions qu’ont les élèves du système. Les résultats de l’expérience n’ont indiqué aucune différence statistiquement significative entre le groupe expéri- mental et le groupe témoin, ce qui portait à croire que le CHLS n’avait pas eu d’impact sur le rendement global des élèves. Une fois les données ventilées par niveau de compétence par contre, elles ont révélé des différences statistiquement significatives entre les élèves avancés du groupe expérimental et ceux du groupe témoin. Les résultats de l’enquête ont indiqué que le CHLS était particulièrement efficace chez les élèves motivés à participer aux activités académiques et capables d’apprendre de façon autonome. On peut considérer le CHLS un complément utile à l’apprentissage, mais pas une solution de remplacement aux services de tutorat privé. Afin de mieux répondre aux besoins des autres apprenants, il se peut que le contenu en anglais du CHLS doive être modifié davantage de sorte à refléter les niveaux de compétence et les styles d’apprentissage variés.
9
Lin, C., S. C. Popescu, S. C. Huang, P. T. Chang, and H. L. Wen. "A novel reflectance-based model for evaluating chlorophyll concentrations of fresh and water-stressed leaves." Biogeosciences 12, no. 1 (2015): 49–66. http://dx.doi.org/10.5194/bg-12-49-2015.
Full textAbstract:
Abstract. Water deficits can cause chlorophyll degradation which decreases the total concentration of chlorophyll a and b (Chls). Few studies have investigated the effectiveness of spectral indices under water-stressed conditions. Chlorophyll meters have been extensively used for a wide variety of leaf chlorophyll and nitrogen estimations. Since a chlorophyll meter works by sensing leaves absorptance and transmittance, the reading of chlorophyll concentration will be affected by changes in transmittance as if there were a water deficit in the leaves. The overall objective of this paper was to develop a novel and reliable reflectance-based model for estimating Chls of fresh and water-stressed leaves using the reflectance at the absorption bands of chlorophyll a and b and the red edge spectrum. Three independent experiments were designed to collect data from three leaf sample sets for the construction and validation of Chls estimation models. First, a reflectance experiment was conducted to collect foliar Chls and reflectance of leaves with varying water stress using the ASD FieldSpec spectroradiometer. Second, a chlorophyll meter (SPAD-502) experiment was carried out to collect foliar Chls and meter readings. These two data sets were separately used for developing reflectance-based or absorptance-based Chls estimation models using linear and nonlinear regression analysis. Suitable models were suggested mainly based on the coefficient of determination (R2). Finally, an experiment was conducted to collect the third data set for the validation of Chls models using the root mean squared error (RMSE) and the mean absolute error (MAE). In all of the experiments, the observations (real values) of the foliar Chls were extracted from acetone solution and determined by using a Hitachi U-2000 spectrophotometer. The spectral indices in the form of reflectance ratio/difference/slope derived from the Chl b absorption bands (ρ645 and ρ455) provided Chls estimates with RMSE around 0.40–0.55 mg g−1 for both fresh and water-stressed samples. We improved Chls prediction accuracy by incorporating the reflectance at red edge position (ρREP) in regression models. An effective chlorophyll indicator with the form of (ρ645–ρ455)/ρREP proved to be the most accurate and stable predictor for foliar Chls concentration. This model was derived with an R2 of 0.90 (P < 0.01) from the training samples and evaluated with RMSE 0.35 and 0.38 mg g−1 for the validation samples of fresh and water-stressed leaves, respectively. The average prediction error was within 14% of the mean absolute error.
10
Phillips, Charles D., Obioma Nwaiwu, Szu-hsuan Lin, Rachel Edwards, Sara Imanpour, and Robert Ohsfeldt. "Concealed Handgun Licensing and Crime in Four States." Journal of Criminology 2015 (June 16, 2015): 1–8. http://dx.doi.org/10.1155/2015/803742.
Full textAbstract:
Firearm policy in the United States has long been a serious policy issue. Much of the previous research on crime and firearms focused on the effects of states’ passage of concealed handgun licensing (CHL) legislation. Today, given the proliferation of CHL legislation and growing strength of the “pro-gun” movement, the primary policy focus has changed. State legislators now face issues concerning whether and how to increase access to CHLs. Because of this transformation, this research moves away from the research tradition focused on the effect of a legislative change allowing CHLs. Instead, we consider two issues more policy relevant in the current era: What are the dynamics behind CHL licensing? Do increases in concealed handgun licensing affect crime rates? Using county-level data, we found that the density of gun dealers and other contextual variables, rather than changing crime rates, had a significant effect on increases of the rates at which CHLs were issued. We also found no significant effect of CHL increases on changes in crime rates. This research suggests that the rate at which CHLs are issued and crime rates are independent of one another—crime does not drive CHLs; CHLs do not drive crime.
11
Carbone, Antonino, Annunziata Gloghini, and Carmelo Carlo-Stella. "Are EBV-related and EBV-unrelated Hodgkin lymphomas different with regard to susceptibility to checkpoint blockade?" Blood 132, no. 1 (2018): 17–22. http://dx.doi.org/10.1182/blood-2018-02-833806.
Full textAbstract:
Abstract Epstein-Barr virus (EBV)–related and EBV-unrelated classical Hodgkin lymphomas (cHLs) are morphologically and phenotypically indistinguishable. However, the tumor microenvironment of EBV-related cHLs contains higher numbers of macrophages and higher expression levels of PD-L1 than that of EBV-unrelated cHLs. Moreover, viral oncoprotein LMP1 may sustain an immunosuppressive microenvironment by inducing/enhancing production of immunosuppressive cytokines and the expression of PD-1. The presence of enhanced immunosuppressive features in EBV-related cHL should make EBV-related cHL patients more susceptible to checkpoint blockade.
12
Taguchi, Naoko, Haomin Zhang, and Qiong Li. "Pragmatic competence of heritage learners of Chinese and its relationship to social contact." Chinese as a Second Language Research 6, no. 1 (2017): 7–37. http://dx.doi.org/10.1515/caslar-2017-0002.
Full textAbstract:
AbstractThis study aimed to investigate: (1) Chinese heritage learners’ (CHLs) pragmatic competence in comparison to foreign language learners of Chinese (CFLs) and (2) the relationship between CHLs’ pragmatic competence and their language contact in a range of social settings. Focal linguistic forms included sentence final particles (SFPs) and formulaic expressions (FORs). Sixty Chinese language learners in the intermediate- and advanced-level classes (31 CHLs and 29 CFLs) participated in the study. Participants completed a computerized listening comprehension task, a written production task, and a language contact questionnaire. Findings showed that CHLs outperformed CFLs in both comprehension and production of Chinese sentence final particles and formulaic expressions. The analysis of language contact questionnaire revealed that learners who reported a greater amount of interactive language contact achieved higher scores on the pragmatic tasks, regardless of the constructs and skill domains assessed.
13
Cader, Fathima Zumla, Ron C. J. Schackmann, Xihao Hu, et al. "Mass cytometry of Hodgkin lymphoma reveals a CD4+ regulatory T-cell–rich and exhausted T-effector microenvironment." Blood 132, no. 8 (2018): 825–36. http://dx.doi.org/10.1182/blood-2018-04-843714.
Full textAbstract:
Key Points Newly diagnosed primary cHLs have a concomitant increase in CD4+ Th1-polarized Tregs and differentiated Teffs. Primary cHLs exhibit 2 major complementary bases of immunosuppression: likely exhausted PD-1+ Th1 Teffs and active PD-1− Th1 Tregs.
14
Prete, M. Irene, Gianluigi Guido, and Marco Pichierri. "Consumer Hypnotic-Like Suggestibility: Possible Mechanism in Compulsive Purchasing." Psychological Reports 113, no. 1 (2013): 162–74. http://dx.doi.org/10.2466/01.18.pr0.113x11z0.
Full textAbstract:
The authors hypothesize a concept, Consumer Hypnotic-Like Suggestibility (CHLS), defined as an altered state of consciousness, as a state causing a tendency to respond positively to messages aimed at inducing consumers to make unplanned purchases. This study aims to investigate the associations of CHLS with interpersonal variables and compulsive purchasing—a frequent and uncontrollable preoccupation with buying or impulses to buy. A study was conducted on a sample of 232 subjects ( n = 111 men; M age = 41 yr.), through the administration of a questionnaire, which measured: CHLS, compulsive purchasing, consumer susceptibility to interpersonal influence (the necessity to enhance one's image in the opinion of others through the consumption of products), and consumer atmospherics, i.e., environmental stimuli known to influence purchasing decisions. Modeling and mediation analyses suggested that internal and external drivers—Consumer Susceptibility to Interpersonal Influence and atmospherics—are positively related to CHLS which affects compulsive purchasing.
15
Akhtar, Parveen, Avratanu Biswas, László Kovács, Nathan Nelson, and Petar H. Lambrev. "Excitation energy transfer kinetics of trimeric, monomeric and subunit-depleted Photosystem I from Synechocystis PCC 6803." Biochemical Journal 478, no. 7 (2021): 1333–46. http://dx.doi.org/10.1042/bcj20210021.
Full textAbstract:
Photosystem I is the most efficient photosynthetic enzyme with structure and composition highly conserved among all oxygenic phototrophs. Cyanobacterial Photosystem I is typically associated into trimers for reasons that are still debated. Almost universally, Photosystem I contains a number of long-wavelength-absorbing ‘red’ chlorophylls (Chls), that have a sizeable effect on the excitation energy transfer and trapping. Here we present spectroscopic comparison of trimeric Photosystem I from Synechocystis PCC 6803 with a monomeric complex from the ΔpsaL mutant and a ‘minimal’ monomeric complex ΔFIJL, containing only subunits A, B, C, D, E, K and M. The quantum yield of photochemistry at room temperature was the same in all complexes, demonstrating the functional robustness of this photosystem. The monomeric complexes had a reduced far-red absorption and emission equivalent to the loss of 1.5–2 red Chls emitting at 710–715 nm, whereas the longest-wavelength emission at 722 nm was not affected. The picosecond fluorescence kinetics at 77 K showed spectrally and kinetically distinct red Chls in all complexes and equilibration times of up to 50 ps. We found that the red Chls are not irreversible traps at 77 K but can still transfer excitations to the reaction centre, especially in the trimeric complexes. Structure-based Förster energy transfer calculations support the assignment of the lowest-energy state to the Chl pair B37/B38 and the trimer-specific red Chl emission to Chls A32/B7 located at the monomer–monomer interface. These intermediate-energy red Chls facilitate energy migration from the lowest-energy states to the reaction centre.
16
Li, Qiong, Haomin Zhang, and Naoko Taguchi. "The Use of Mitigation Devices in Heritage Learners of Chinese." Heritage Language Journal 14, no. 2 (2017): 150–70. http://dx.doi.org/10.46538/hlj.14.2.3.
Full textAbstract:
This study investigated the pragmatic competence of Chinese heritage learners (CHLs) on the use of three Chinese-specific mitigation devices: Chinese sentence final particles (SFPs), yixia/xia “for a while”, and reduplication of verbs. Their performances were compared with those of foreign language learners of Chinese (CFLs) and native Chinese speakers (NSs). Twenty-three NSs and 60 Chinese language learners in the intermediate and advanced-level classes (31 CHLs and 29 CFLs) participated in the study. Participants completed a computerized written production task that included two types of situations (PD-low and high situations) based on two contextual factors: the power relationship (P) and social distance (D). The statistical findings showed no notable significant heritage advantage; however, the post-hoc analysis revealed the unique nature of CHLs’ pragmatic competence, vacillating between CFLs and NSs. Specifically, CHLs outperformed CFLs in the use of SFPs and yixia/xia in both PD-low and high situations, but they fell behind the NSs in certain aspects, especially in their linguistic knowledge on SFPs and yixia/xia.
17
Morales-Aleman, Mercedes M., Artisha Moore, and Isabel C. Scarinci. "Development of a Participatory Capacity- Building Program for Congregational Health Leaders in African American Churches in the US South." Ethnicity & Disease 28, no. 1 (2018): 11. http://dx.doi.org/10.18865/ed.28.1.11.
Full textAbstract:
<p>African Americans are disproportionately affected by diabetes and colorectal cancer. Although studies have shown the effectiveness of spiritually based health interventions delivered by community health workers to African Americans, few have described the development of the capacity-building component. This article describes this process. The development of the Healthy Congregations Healthy Communities Program (HCHC) was guided through a community-based participatory research lens and included: 1) establishment of a community coalition; 2) identification by coalition members of churches as the best venues for health promotion strategies among African Americans; 3) recruitment of churches; 4) development of a training manual; 5) recruitment and training of congregational health leaders (CHLs); and 6) “Passing of the torch” from the coalition to the CHLs who implemented the intervention in their congregations. We trained 35 CHLs to promote awareness about diabetes and colorectal cancer using a culturally relevant, spiritually based curriculum. Pre- and post-test paired t-tests showed significant increases in CHLs’ knowledge of wellness (P&lt;.001), colorectal cancer (P&lt;.002), nutrition (P&lt;.004), and lifestyle changes (P&lt;.005). The community-academic partnership was successful in developing a culturally relevant, spiritually based capacity-building program for African American CHLs to implement health promotion strategies in their congregations and communities.</p><p><em>Ethn Dis.</em>2018;28(1):11-18; doi:10.18865/ed.28.1.11.</p>
18
Karlický, Václav, Zuzana Kmecová Materová, Irena Kurasová, et al. "Accumulation of geranylgeranylated chlorophylls in the pigment-protein complexes of Arabidopsis thaliana acclimated to green light: effects on the organization of light-harvesting complex II and photosystem II functions." Photosynthesis Research 149, no. 1-2 (2021): 233–52. http://dx.doi.org/10.1007/s11120-021-00827-1.
Full textAbstract:
AbstractLight quality significantly influences plant metabolism, growth and development. Recently, we have demonstrated that leaves of barley and other plant species grown under monochromatic green light (500–590 nm) accumulated a large pool of chlorophyll a (Chl a) intermediates with incomplete hydrogenation of their phytyl chains. In this work, we studied accumulation of these geranylgeranylated Chls a and b in pigment-protein complexes (PPCs) of Arabidopsis plants acclimated to green light and their structural–functional consequences on the photosynthetic apparatus. We found that geranylgeranylated Chls are present in all major PPCs, although their presence was more pronounced in light-harvesting complex II (LHCII) and less prominent in supercomplexes of photosystem II (PSII). Accumulation of geranylgeranylated Chls hampered the formation of PSII and PSI super- and megacomplexes in the thylakoid membranes as well as their assembly into chiral macrodomains; it also lowered the temperature stability of the PPCs, especially that of LHCII trimers, which led to their monomerization and an anomaly in the photoprotective mechanism of non-photochemical quenching. Role of geranylgeranylated Chls in adverse effects on photosynthetic apparatus of plants acclimated to green light is discussed.
19
Wang, Wenda, Long-Jiang Yu, Caizhe Xu, et al. "Structural basis for blue-green light harvesting and energy dissipation in diatoms." Science 363, no. 6427 (2019): eaav0365. http://dx.doi.org/10.1126/science.aav0365.
Full textAbstract:
Diatoms are abundant photosynthetic organisms in aquatic environments and contribute 40% of its primary productivity. An important factor that contributes to the success of diatoms is their fucoxanthin chlorophyll a/c-binding proteins (FCPs), which have exceptional light-harvesting and photoprotection capabilities. Here, we report the crystal structure of an FCP from the marine diatom Phaeodactylum tricornutum, which reveals the binding of seven chlorophylls (Chls) a, two Chls c, seven fucoxanthins (Fxs), and probably one diadinoxanthin within the protein scaffold. Efficient energy transfer pathways can be found between Chl a and c, and each Fx is surrounded by Chls, enabling the energy transfer and quenching via Fx highly efficient. The structure provides a basis for elucidating the mechanisms of blue-green light harvesting, energy transfer, and dissipation in diatoms.
20
Betke, Alexander, and Heiko Lokstein. "Two-photon excitation spectroscopy of photosynthetic light-harvesting complexes and pigments." Faraday Discussions 216 (2019): 494–506. http://dx.doi.org/10.1039/c8fd00198g.
Full textAbstract:
Two-photon excitation (TPE) profiles of LHCII samples containing different xanthophyll complements were measured in the presumed 1<sup>1</sup>A<sub>g</sub><sup>−</sup> → 2<sup>1</sup>A<sub>g</sub><sup>−</sup> (S<sub>0</sub> → S<sub>1</sub>) transition region of xanthophylls. Additionally, TPE profiles of Chls a and b in solution and of WSCP, which does not contain carotenoids, were measured. The results indicate that direct two-photon absorption by Chls in the presumed S<sub>0</sub> → S<sub>1</sub> transition spectral region of carotenoids is dominant over that of carotenoids, with negligible contributions of the latter. These results suggest the re-evaluation of previously published TPE data obtained with photosynthetic pigment–protein complexes containing (B)Chls and carotenoids.
21
Chen, Jing-Hua, Hangjun Wu, Caihuang Xu, et al. "Architecture of the photosynthetic complex from a green sulfur bacterium." Science 370, no. 6519 (2020): eabb6350. http://dx.doi.org/10.1126/science.abb6350.
Full textAbstract:
The photosynthetic apparatus of green sulfur bacteria (GSB) contains a peripheral antenna chlorosome, light-harvesting Fenna-Matthews-Olson proteins (FMO), and a reaction center (GsbRC). We used cryo–electron microscopy to determine a 2.7-angstrom structure of the FMO-GsbRC supercomplex from Chlorobaculum tepidum. The GsbRC binds considerably fewer (bacterio)chlorophylls [(B)Chls] than other known type I RCs do, and the organization of (B)Chls is similar to that in photosystem II. Two BChl layers in GsbRC are not connected by Chls, as seen in other RCs, but associate with two carotenoid derivatives. Relatively long distances of 22 to 33 angstroms were observed between BChls of FMO and GsbRC, consistent with the inefficient energy transfer between these entities. The structure contains common features of both type I and type II RCs and provides insight into the evolution of photosynthetic RCs.
22
Kume, Atsushi, Tomoko Akitsu, and Kenlo Nishida Nasahara. "Why is chlorophyll b only used in light-harvesting systems?" Journal of Plant Research 131, no. 6 (2018): 961–72. http://dx.doi.org/10.1007/s10265-018-1052-7.
Full textAbstract:
Abstract Chlorophylls (Chl) are important pigments in plants that are used to absorb photons and release electrons. There are several types of Chls but terrestrial plants only possess two of these: Chls a and b. The two pigments form light-harvesting Chl a/b-binding protein complexes (LHC), which absorb most of the light. The peak wavelengths of the absorption spectra of Chls a and b differ by c. 20 nm, and the ratio between them (the a/b ratio) is an important determinant of the light absorption efficiency of photosynthesis (i.e., the antenna size). Here, we investigated why Chl b is used in LHCs rather than other light-absorbing pigments that can be used for photosynthesis by considering the solar radiation spectrum under field conditions. We found that direct and diffuse solar radiation (PARdir and PARdiff, respectively) have different spectral distributions, showing maximum spectral photon flux densities (SPFD) at c. 680 and 460 nm, respectively, during the daytime. The spectral absorbance spectra of Chls a and b functioned complementary to each other, and the absorbance peaks of Chl b were nested within those of Chl a. The absorption peak in the short wavelength region of Chl b in the proteinaceous environment occurred at c. 460 nm, making it suitable for absorbing the PARdiff, but not suitable for avoiding the high spectral irradiance (SIR) waveband of PARdir. In contrast, Chl a effectively avoided the high SPFD and/or high SIR waveband. The absorption spectra of photosynthetic complexes were negatively correlated with SPFD spectra, but LHCs with low a/b ratios were more positively correlated with SIR spectra. These findings indicate that the spectra of the photosynthetic pigments and constructed photosystems and antenna proteins significantly align with the terrestrial solar spectra to allow the safe and efficient use of solar radiation.
23
Shapira, Harel, Katherine Jensen, and Ken-Hou Lin. "Trends and Patterns of Concealed Handgun License Applications: A Multistate Analysis." Social Currents 5, no. 1 (2017): 3–14. http://dx.doi.org/10.1177/2329496517725334.
Full textAbstract:
Recent waves of legislation have made it much easier for gun owners to obtain a Concealed Handgun License (CHL) and thereby carry their guns in public except when explicitly prohibited. Because data are difficult to access, our understanding of who seeks and obtains such licenses remains limited. Using data obtained through Freedom of Information Act requests, this article fills this empirical gap by describing demographic trends and characteristics of applicants for CHLs in five states: Florida, Indiana, Massachusetts, Texas, and Utah. The results establish that (1) applications for CHLs are growing at fast rates; (2) there are significant gender and racial disparities in terms of who applies for CHLs, with men 2.9 to 5.5 times more likely to apply than women, and whites 1.3 to 2.0 times more likely to apply than blacks; (3) in Florida and Utah, these demographic gaps have widened over time; and (4) there are significant racial disparities in terms of application outcomes, with black applicants being 3.3 to 5.5 times more likely to be denied a license than white applicants. Moreover, we do not find the patterns in Massachusetts, a may-issue state, to be significantly different from the shall-issue states in our sample.
24
Charbonnier, Aude, Michel Raba, Patrick Ladaique, et al. "Preventive Versus Curative Platelet Transfusion Strategies in the Treatment of Acute Myeloid Leukemia Patients: A Comparative Study." Blood 124, no. 21 (2014): 4288. http://dx.doi.org/10.1182/blood.v124.21.4288.4288.
Full textAbstract:
Abstract Different transfusion care strategies are considered for the treatment of acute thrombopenia due to low or absence of production of platelets in Acute Myeloid Leukemia (AML) patients with controversies about both threshold of platelets to consider prior to transfusion and the quality of the product to transfuse. In addition, despite two recent studies (Wandt et al, Lancet. 2012 Oct 13;380:1309; Stanworth and al. N Engl J Med. 2013 May 9;368:1771), the choice between preventive (based upon the number of platelets) and curative (based on clinical symptoms) care, as discussed in 2004 by Slichter and al. (Transfus Med Rev. 2004 Jul;18(3):153), still remains a concern although preventive care is commonly used. In this study, we compared the treatment of AML patients at the Institut Paoli-Calmettes (Marseille, France, that elicited curative transfusion care strategy) herein called IPC, and Centre Hospitalier Lyon Sud (Pierre Benite, France, that elicited preventive transfusion care strategy) herein called CHLS, between January 2001 and December 2010, considering the use of transfusion product during induction, and death due to hemorrhage. At the time of study, the curative transfusion care strategy at the IPC relied on the analysis of three complete blood counts a week, clinical examination of the patients (Pt) at least twice a day, and platelet transfusion in case of mucosal hemorrhage syndrome, headaches, fever, and high blood pressure. At the CHLS, the preventive transfusion care strategy relied on blood count, daily clinical examination of the Pt, and platelet transfusion when platelet number was found below 20 G/L. Both IPC and CHLS used Platelet Concentrate (PC) obtained from apheresis from single donor (CPA) or multiple donors (MCPS) and a threshold of 80 g/l Hb was considered for red blood cell transfusion. AML patients were treated by cytarabine combined with anthracycline (induction regimen), with subtle differences between CHLS and IPC and according to recommendation at the time of treatment. Our analysis covered a 45 day induction time, and the 6 first months (185 days) of treatment. Between January 2001 and December 2010, 884 patients (median age 59 with 80% < 70) and 524 patients (median age 52 with 94% <70) were treated at the IPC and at the CHLS, respectively. 74% vs 82% of the patients underwent complete remission (CR) following one or two induction regimens, and 39% vs 40% are still alive. During induction, patients at the IPC and the CHLS received 5,1 ± 3,9 (mean ± Standard Deviation) and 10,2 ± 7 PC, with 4,4 and 9,8 CPA and 1,3 and 1,3 MCPS, respectively. During this period, the number of packed red blood cell unit used was 5.7 ± 4,6 and 10.6 ± 5,8, respectively, and 21 Pts deceased from hemorrhage at the IPC versus 2 at the CHLS, with 9 Pts refractory to platelet transfusion versus 1. When not considering Pts refractory to transfusion and Pts with disseminated intravascular coagulation (DIC), 7 Pts died at the IPC (at a median of 12 days after diagnosis) versus 1 patient at the CHLS at day 16 after diagnosis. Of note, ≥ grade 3 sepsis supported in intensive care unit was observed in 5 over 7 patients at the IPC. This retrospective study confirms the results suggested in the TOPPS and German studies that have compared preventive and curative platelet transfusion strategies for leukemia patients. Two fold less platelet products are used in a curative strategy, but more patients deceased from hemorrhage, most of them earlier during the treatment and with high grade sepsis. Unexpectedly, two fold more packed red blood cell units are used in the preventive strategy. This study also suggests that increase of the number of platelet concentrate infused without regard to ABO typing could decrease the therapeutical impact of red blood cell transfusion. At the IPC, high number of patients deceased from hemorrhage in context of DIC or refractoriness to transfusion may be relied to the platelet and plasma transfusion strategy elicited in these particular situations. Altogether, these results suggest that risk factors like sepsis, have to be considered to elicit a preventive versus curative platelet transfusion strategy in the treatment of AML Patient. Six months results and further statistical analyses are in progress and will be presented. Disclosures Prebet: Celgene Corporation: Honoraria. Vey:BMS: Honoraria.
25
Venkataraman, Girish, Joo Y. Song, Alexandar Tzankov, et al. "Aberrant T-cell antigen expression in classical Hodgkin lymphoma is associated with decreased event-free survival and overall survival." Blood 121, no. 10 (2013): 1795–804. http://dx.doi.org/10.1182/blood-2012-06-439455.
Full text
26
Komatsu, Yu, Masayuki Umemura, Mitsuo Shoji, Megumi Kayanuma, Kazuhiro Yabana, and Kenji Shiraishi. "Light absorption efficiencies of photosynthetic pigments: the dependence on spectral types of central stars." International Journal of Astrobiology 14, no. 3 (2014): 505–10. http://dx.doi.org/10.1017/s147355041400072x.
Full textAbstract:
AbstractFor detecting life from reflection spectra on extrasolar planets, trace of photosynthesis is one of the indicators. However, it is not yet clear what kind of radiation environments is acceptable for photosynthesis. Light absorption in photosystems on the Earth occurs using limited photosynthetic pigments such as chlorophylls (Chls) and bacteriochlorophylls (BChls). Efficiencies of light absorption for the pigments were evaluated by calculating the specific molecular absorption spectra at the high accuracy-quantum mechanical level. We used realistic stellar radiation spectra such as F, G, K and M-type stars to investigate the efficiencies. We found that the efficiencies are increased with the temperature of stars, from M to F star. Photosynthetic pigments have two types of absorption bands, the Qy and Soret. In higher temperature stars like F star, contributions from the Soret region of the pigments are dominant for the efficiency. On the other hand, in lower temperature stars like M stars, the Qy band is crucial. Therefore, differences on the absorption intensity and the wavelength between the Qy and Soret band are the most important to characterize the photosynthetic pigments. Among photosynthetic pigments, Chls tend to be efficient in higher temperature stars, while BChls are efficient for M stars. Blueward of the 4000 Å break, the efficiencies of BChls are smaller than Chls in the higher temperature stars.
27
Schmitz, Roland, Martin-Leo Hansmann, Verena Bohle, et al. "TNFAIP3 (A20) is a tumor suppressor gene in Hodgkin lymphoma and primary mediastinal B cell lymphoma." Journal of Experimental Medicine 206, no. 5 (2009): 981–89. http://dx.doi.org/10.1084/jem.20090528.
Full textAbstract:
Proliferation and survival of Hodgkin and Reed/Sternberg (HRS) cells, the malignant cells of classical Hodgkin lymphoma (cHL), are dependent on constitutive activation of nuclear factor κB (NF-κB). NF-κB activation through various stimuli is negatively regulated by the zinc finger protein A20. To determine whether A20 contributes to the pathogenesis of cHL, we sequenced TNFAIP3, encoding A20, in HL cell lines and laser-microdissected HRS cells from cHL biopsies. We detected somatic mutations in 16 out of 36 cHLs (44%), including missense mutations in 2 out of 16 Epstein-Barr virus–positive (EBV+) cHLs and a missense mutation, nonsense mutations, and frameshift-causing insertions or deletions in 14 out of 20 EBV− cHLs. In most mutated cases, both TNFAIP3 alleles were inactivated, including frequent chromosomal deletions of TNFAIP3. Reconstitution of wild-type TNFAIP3 in A20-deficient cHL cell lines revealed a significant decrease in transcripts of selected NF-κB target genes and caused cytotoxicity. Extending the mutation analysis to primary mediastinal B cell lymphoma (PMBL), another lymphoma with constitutive NF-κB activity, revealed destructive mutations in 5 out of 14 PMBLs (36%). This report identifies TNFAIP3 (A20), a key regulator of NF-κB activity, as a novel tumor suppressor gene in cHL and PMBL. The significantly higher frequency of TNFAIP3 mutations in EBV− than EBV+ cHL suggests complementing functions of TNFAIP3 inactivation and EBV infection in cHL pathogenesis.
28
Tilahun, Shimeles, Hee Sung An, Tifsehit Solomon, et al. "Indices for the Assessment of Glycoalkaloids in Potato Tubers Based on Surface Color and Chlorophyll Content." Horticulturae 6, no. 4 (2020): 107. http://dx.doi.org/10.3390/horticulturae6040107.
Full textAbstract:
Glycoalkaloids (GAs) are toxic to humans at higher concentrations. However, studies also suggest the health benefits of GAs depending on the dose and conditions of use. Methods that have been used to determine GA content in potato tubers are destructive and time-consuming and require skilled personnel and high-performance laboratory equipment. We conducted this study to develop indices for the prediction of the level of total GAs in potato tubers at different greening stages based on surface color readings and chlorophyll (Chl) development. Color values (Hunter L*, a*, b*, a*/b*), Chls (Chl a, Chl b, and total Chls) and GA (α-solanine, α-chaconine, and total GAs) content were measured from tubers of ‘Atlantic’ and ‘Trent’ potato cultivars at three-week intervals in up to six greening stages during the storage at room conditions (22 °C, 12-h shift of light-dark cycles). The results have revealed that greening, Chls, and GA content significantly increased for the two cultivars as the stage proceeded. The toxic level of GAs (>200 mg kg−1 FW) was accumulated at the late greening stages, accompanied by the highest Chl content. Finally, indices were developed based on surface color and Chl content for estimation of the safe GA levels for the consumption of the two commercially and commonly used potato cultivars. Moreover, the developed indices could be used as basic information to adapt to other potato cultivars.
29
Yamauchi, Naoki, and Alley E. Watada. "Regulated Chlorophyll Degradation in Spinach Leaves during Storage." Journal of the American Society for Horticultural Science 116, no. 1 (1991): 58–62. http://dx.doi.org/10.21273/jashs.116.1.58.
Full textAbstract:
Degradation of chlorophyll in spinach (Spinacia olearacea L. cv. Hybrid 612) appeared to be regulated through the peroxidase-hydrogen peroxide pathway, which opens the porphyrin ring, thus resulting in a colorless compound. This conclusion was arrived at from the analysis of chlorophylls (Chls) and their metabolizes by HPLC and of enzyme activities catalyzing the degradative reactions. Chls decreased at 25C but not at 1C. The chlorophyll oxidase pathway was not active, as noted by the lack of accumulation of a reaction product named Chl a-1. Lipid peroxidation increased with storage, but the products of the reaction. did not degrade chlorophyll, as noted by the lack of increase in Chl a-1. Chlorophyllase activity increased, but chlorophyllide, the expected product of the reaction, changed minimally during senescence. Ethylene at 10 ppm did not alter the pathway that degraded chlorophyll in spinach.
30
Wienand, Kirsty, Bjoern Chapuy, Chip Stewart, et al. "Genomic analyses of flow-sorted Hodgkin Reed-Sternberg cells reveal complementary mechanisms of immune evasion." Blood Advances 3, no. 23 (2019): 4065–80. http://dx.doi.org/10.1182/bloodadvances.2019001012.
Full textAbstract:
Key Points Analyses of recurrent mutations, copy number alterations, and structural variants reveal complementary immune evasion mechanisms in cHL. The mutational burden in EBV– cHLs is among the highest reported, potentially contributing to the efficacy of PD-1 blockade.
31
Wienand, Kirsty, Bjoern Chapuy, Chip Stewart, et al. "Comparative Genomic Analyses Defines Shared and Unique Features of cHL and PMBL and New Mechanisms of Sensitivity to PD-1 Blockade." Blood 134, Supplement_1 (2019): 1493. http://dx.doi.org/10.1182/blood-2019-131904.
Full textAbstract:
Classical Hodgkin lymphoma (cHL) and primary mediastinal large B-cell lymphoma (PMBL) are aggressive tumors with distinct cells of origin and pathomorphological features. However, these lymphomas share certain transcriptional signatures and aberrant signaling pathways. CHLs and PMBLs both exhibit constitutive activation of NF-κB and JAK/STAT signaling and genetic bases of PD-1 mediated immune evasion including frequent 9p24.1/PD-L1/PD-L2 copy gains. In both lymphomas, PD-1 blockade is a FDA-approved therapy for relapsed/refractory disease. To characterize genetic bases of response to PD-1 blockade and identify complementary treatment targets in cHL and PMBL, we defined the comprehensive genetic signatures of both diseases. First, we obtained flow cytometry-sorted Hodgkin Reed Sternberg (HRS) cells from 23 biopsies of newly diagnosed cHLs and intact tumor biopsy specimens from 37 newly diagnosed PMBLs. The isolated HRS cells and paired normal DNAs and PMBL biopsy specimens were subjected to whole exome sequencing using an optimized workflow for low input samples and an expanded bait set to capture structural variants (SVs), including translocations. We used newly developed and established analytical pipelines to analyze tumor samples without paired normals (PMBLs) and identify significantly mutated genes (candidate cancer genes [CCGs], MutSig2CV, CLUMPS), SCNAs (GISTIC2.0) and SVs(4 algorithms) in both cHL and PMBL. In cHL, we identified 15 CCGs, 13 recurrent SCNAs, SVs in ETV6 and CIITA, complementary alterations of JAK/STAT, NF-κB and PI3K signaling pathway components and a median number of 11 genetic drivers per tumor. Previously unappreciated aspects of the cHL genetic signature included the increased incidence of driver mutational events in cHLs with ARID1A alterations (p=0.012). Analyses of co-occurring genetic events in EBV+ and EBV- cHLs confirmed that EBV- cHLs were significantly more likely to exhibit alterations of specific NF-κB signaling intermediaries (such as TNFAIP3 mutation and/or focal copy loss, p=0.006) and perturbations of MHC class I antigen presentation pathway components (inactivating B2M mutations, HLA-B mutations or focal copy loss of 6p21.32/HLA-B, p=0.008). The latter findings provide genetic bases for the reported differences in cell surface expression of MHC class I in EBV+ and EBV- cHLs. In PMBL, we defined 15 CCGs and more selective perturbations of specific epigenetic modifiers (ZNF217 and EZH2), transcription factors (PAX5 and IRF2BP2) and TP53, in comparison with cHL. The majority of these alterations were clonal supporting their role as early drivers. We identified 18 SCNAs and additional SVs in CIITA and PD-1 ligands, recurrent alterations of JAK/STAT and NF-κB signaling pathway components and a median of 9 genetic drivers per PMBL. Antigen presentation pathways in PMBL were perturbed by multiple recurrent alterations, including B2M mutations, focal copy losses of B2M and the MHCI/II loci, SVs of CTIIA and EZH2 mutations. There was a significant correlation between genetic perturbations of MHC class I pathway components and absence of MHC class I expression in PMBL, as previously described in cHL. Recurrent cHL alterations including B2M, TNFAIP3, STAT6, GNA13 and XPO1 CCGs and 2p/2p15/2p16.1, 6p21.32, 6q23.2 and 9p/9p24.1 SCNAs were also identified in &gt;20% of PMBLs, highlighting shared pathogenetic mechanisms in these diseases. These tumors of predominantly young adults (median age: cHL 26 yrs; PMBL 34 yrs) both had a high rate of spontaneous deamination of CpGs, a clock-like mutational signature that is typically associated with aging. CHLs and PMBLs both exhibited previously uncharacterized molecular features that may increase sensitivity to PD-1 blockade, including high mutational burdens, in comparison with other lymphoid and solid tumors. In particular, the mutational burden in EBV- cHLs was among the highest reported, similar to that in carcinogen-induced cancers (melanoma and NSCLC). Additionally, both cHLs and PMBLs had an increased incidence of microsatellite instability and APOBEC mutational signatures, features associated with a more favorable response to PD-1 blockade. Taken together, these data define genetic similarities and differences in cHL and PMBL and establish a framework to comprehensively assess molecular bases of response to PD-1 blockade and develop rational combination therapies in these diseases. Disclosures Armand: Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Otsuka: Research Funding; Sigma Tau: Research Funding; Adaptive: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Affimed: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; Pfizer: Consultancy; ADC Therapeutics: Consultancy; Infinity: Consultancy; Genentech: Research Funding; Tensha: Research Funding. Rodig:Merck: Research Funding; Affirmed: Research Funding; Kite, a Gilead Company: Research Funding; Bristol Myers Squib: Consultancy, Honoraria, Other: Travel Expenses, Speakers Bureau. Fromm:Merck, Inc.: Research Funding. Getz:Pharmacyclics: Research Funding; IBM: Research Funding; MuTect, ABSOLTUE, MutSig and POLYSOLVER: Patents & Royalties: MuTect, ABSOLTUE, MutSig and POLYSOLVER. Shipp:AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; Merck & Co.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.
32
El-Hendawy, Salah, Salah Elsayed, Nasser Al-Suhaibani, et al. "Use of Hyperspectral Reflectance Sensing for Assessing Growth and Chlorophyll Content of Spring Wheat Grown under Simulated Saline Field Conditions." Plants 10, no. 1 (2021): 101. http://dx.doi.org/10.3390/plants10010101.
Full textAbstract:
The application of proximal hyperspectral sensing, using simple vegetation indices, offers an easy, fast, and non-destructive approach for assessing various plant variables related to salinity tolerance. Because most existing indices are site- and species-specific, published indices must be further validated when they are applied to other conditions and abiotic stress. This study compared the performance of various published and newly constructed indices, which differ in algorithm forms and wavelength combinations, for remotely assessing the shoot dry weight (SDW) as well as chlorophyll a (Chla), chlorophyll b (Chlb), and chlorophyll a+b (Chlt) content of two wheat genotypes exposed to three salinity levels. Stepwise multiple linear regression (SMLR) was used to extract the most influential indices within each spectral reflectance index (SRI) type. Linear regression based on influential indices was applied to predict plant variables in distinct conditions (genotypes, salinity levels, and seasons). The results show that salinity levels, genotypes, and their interaction had significant effects (p ≤ 0.05 and 0.01) on all plant variables and nearly all indices. Almost all indices within each SRI type performed favorably in estimating the plant variables under both salinity levels (6.0 and 12.0 dS m−1) and for the salt-sensitive genotype Sakha 61. The most effective indices extracted from each SRI type by SMLR explained 60%–81% of the total variability in four plant variables. The various predictive models provided a more accurate estimation of Chla and Chlt content than of SDW and Chlb under both salinity levels. They also provided a more accurate estimation of SDW than of Chl content for salt-tolerant genotype Sakha 93, exhibited strong performance for predicting the four variables for Sakha 61, and failed to predict any variables under control and Chlb for Sakha 93. The overall results indicate that the simple form of indices can be used in practice to remotely assess the growth and chlorophyll content of distinct wheat genotypes under saline field conditions.
33
Rubinstein, Paul G., Shylendra Sreenivasappa, Marina Messinger, et al. "Microenvironment Assessment, Disease Characteristics and Prognosis In HIV-Associated (HIV-cHL) and HIV-Negative Classical Hodgkin Lymphoma: The Influence Of Epstein Barr Virus (EBV)." Blood 122, no. 21 (2013): 2996. http://dx.doi.org/10.1182/blood.v122.21.2996.2996.
Full textAbstract:
Abstract Introduction Studies of EBV positive (+) and negative (-) classical Hodgkin lymphoma (cHL) have shown the importance of the immune microenvironment in affecting Reed-Sternberg (hRS) cell survival, proliferation, and biologic behavior. For example, macrophage infiltrates may correlate with inferior disease outcome and survival and proliferation of the hRS cells depends on trophic signals from various inflammatory cells, including CD4+ T cells. The latter finding may explain why HIV-cHL patients (pts) usually present with higher circulating CD4+ T-cell counts (cCD4) compared to HIV-related non-Hodgkin lymphoma. Pathobiologically, HIV-cHL differs from HIV negative cHL (cHL) in that it is nearly always EBV+, has higher numbers of hRS cells, presents with more advanced median stage, exhibits more commonly the mixed cellularity (MC) pattern, and some studies suggest it is more clinically aggressive. To investigate the microenvironment of HIV-cHL and its influence on cHL biology, we assessed the immune cell composition and clinical characteristics of HIV-cHL and compared the findings to those of EBV+ and EBV- cHLs. Methods 31 HIV-cHL and 40 cHL (8 EBV+/32 EBV-) cases were identified and corresponding tissue microarrays (TMAs) created. TMAs were evaluated for EBV (EBER), CD30, and microenvironment-associated antigens: PAX5, CD3, CD4, CD8, CD68, CD163 (% positive), TIA1, FOXP3 (relative number 0-4+); the hRS-macrophage microenvironment was evaluated by assessing the number of hRS where >50% of the circumference of the neoplastic cell was associated with CD68+ cells. Results were compared based on HIV status, EBV status (in HIV negative pts), demographics, cCD4 and histology; each was correlated with overall survival. Analyses were performed using non-parametric Fisher's exact test, Kaplan-Meier method and Cox Proportional Hazards model. Results M:F ratio was 9:1 in the HIV group vs. 1.3:1 in the HIV negative pts (p <0.001). The median cCD4 in the HIV+ pts at HIV-cHL diagnosis was 248 cells/mm3. No differences in age, stage, B symptoms, bulky disease, IPS score, and hRS concentration were found between HIV+ and HIV negative cHLs pts. 7% of cHLs and 33% of HIV-cHLs were classified as MC (p<0.01). 90% of HIV-cHLs were EBV+ compared to 20% of the cHL cases. Statistically significant differences were seen in the number of CD4+ and CD8+ cells between the EBV+ and EBV- cHLs irrespective of HIV status. The only difference among all the immune microenvironment markers observed between EBV+ HIV-cHL and EBV+ cHL cases was that of peri-hRS CD68 cells, which were more abundant in the EBV+ HIV-cHL (Table 1; 51% vs. 30% p<0.005). Similar differences in peri-hRS CD68 staining were observed between the HIV-cHL and all cHL pts. The only deaths in HIV-cHL pts occurred when CD68 was >15% (p<0.05). No statistical differences were noted for OS with respect to cCD4, histologic subtype, race, gender, or HIV status. Conclusions No significant differences were observed between HIV-cHL and cHL pts with respect to stage, B symptoms, bulky disease, IPS score, or overall survival, but there were more MC cases in the HIV-cHL cohort. The microenvironment of HIV-cHL and EBV+ cHL is similar, but different from EBV- cHL with respect to percentages of CD163+, PAX5+, CD4+ and CD8+ cells. The location of CD68+ macrophages was the only discordant result between the EBV+ HIV-cHL and EBV+ cHL cohorts. The differences in location of the CD68+ cells, which may be dependent on HIV status, suggests greater influence of these cells on the biologic behavior of the neoplastic process, correlating with poor survival. However, the similarity in the microenvironments in HIV-cHL and EBV+ cHL with respect to CD4, CD8, and CD163 staining implies an important role for EBV on disease biology, as well. Thus, these data suggest that EBV as well as HIV, play prominent roles in determining the immune response and disease behavior in HIV-cHL, warranting further study Disclosures: No relevant conflicts of interest to declare.
34
Wienand, Kirsty, Bjoern Chapuy, Chip Stewart, et al. "Comprehensive Genomic Analysis of Flow-Sorted Hodgkin Reed Sternberg Cells Reveals Additional Genetic Bases of Immune Evasion." Blood 132, Supplement 1 (2018): 1559. http://dx.doi.org/10.1182/blood-2018-99-118453.
Full textAbstract:
Abstract Classical Hodgkin lymphoma (cHL) is composed of rare malignant Hodgkin Reed Sternberg (HRS) cells within an extensive, but ineffective, inflammatory/immune cell infiltrate. Emerging data suggests that cHLs use multiple genetic mechanisms to evade immune recognition. We previously found that HRS cells exhibit near-universal somatic copy number alterations (SCNAs) involving chromosome 9p24.1/PD-1-L1/PD-L2 and rare chromosomal rearrangements of PD-L1 or PD-L2. The 9p24.1 amplicon also includes JAK2, which increases JAK2 copy numbers, augments JAK2/STAT signaling and further induces PD-1 ligand expression. However, HRS cells also have inactivating mutations of B2M and decreased or absent MHC class I expression. In cHL, clinical responses to PD-1 blockade are unrelated to HRS cell expression of MHC class I but closely associated with HRS cell expression of MHC class II, highlighting the potential role of CD4+ T-cell effectors (J Clin Oncol 2018;36:942-50). To define genetic bases of response and resistance to PD-1 blockade and identify complementary treatment targets, we performed whole exome sequencing (WES) of HRS cells. We first used a previously described multi-color flow cytometric sorting protocol (Methods 2012; 57:368-75) to obtain highly purified CD30+ HRS cells and normal B cells from the excisional biopsies of 25 newly diagnosed cHLs. The isolated HRS cells and paired normal B cells were then subjected to WES using an optimized workflow for low input samples and an expanded bait set to capture structural variants (SVs). We used established analytical pipelines to identify significantly mutated genes (candidate cancer genes [CCGs], MutSig2CV), SCNAs (GISTIC2.0) and SVs (4 algorithms). With improved methodology and purity (median of 80%) of the isolated HRS cells, we defined 15 significantly mutated CCGs, 21 recurrent SCNAs, including 6 CN gains (4 focal and 2 arm level) and 15 CN losses (14 focal and 1 arm level), and low frequency SVs. We identified 2 cHLs as hypermutators with MSI signatures due to splice site mutations in MSH2 or missense mutations in POLE. Excluding the 2 hypermutators, the analyzed cHLs had a median mutational density of 6.4 mutations/Mb, that falls within the top quartile of reported cancer mutational frequencies (Nature 2013 499:214). We also identified a previously unappreciated high incidence of ARID1A mutations (24%) in cHL. This is noteworthy because ARID1A deficiency increases mutational load and augments the efficacy of PD-1 blockade in murine models (Nature Med 2018;24:556). Together, the observed MSI signatures, relatively high mutational burden and newly identified ARID1A mutations in cHL represent additional potential genetic bases for the efficacy of PD-1 blockade. Notably, these cHLs also exhibited recurrent 9p24.1 copy gain (80%) and multiple genetic bases of enhanced JAK/STAT signaling including JAK2 copy gain (80%), STAT6 mutations (32%) involving known hotspots (D419 and N421) in the DNA-binding domain and frequent inactivating SOCS1 mutations (68%). We also identified multiple genetic bases for immune evasion, including B2M inactivating mutations (36%), HLA-B mutations (16%) and 6p21.32/HLA-B copy loss (28%), copy loss of the larger 6p21.32 region and inactivating CIITA SVs (8%). Additional signaling pathways were perturbed by multiple genetic mechanisms in these cHLs. For example, NF-κB pathway alterations included: TNFAIP3 mutations (24%) and 6q23.2/TNFAIP3 copy loss (56%), 12% biallelic; NFKBIE mutations (24%) and 6q21.32/NFKBIE copy loss (12%); and NFKBIA mutations (16%). The gene encoding the nuclear export protein, XPO1, was perturbed by E571K mutations (24%) and frequent 2p15/XPO1 copy gain (72%). Additionally, GNA13, an activator of RHOA and modifier of PI3K signaling, was mutated in 24% of cases. Of interest, cHL recurrent alterations including B2M, TNFAIP3, STAT6, and GNA13 mutations and 6q23.2 and 9p24.1 SCNAs were also identified in > 20% of examined primary mediastinal B-cell lymphomas, highlighting shared pathogenetic mechanisms in these diseases. In summary, comprehensive genomic analyses of purified HRS cells reveal new genetic bases of immune evasion, potential mechanisms of response and resistance to PD-1 blockade and additional targetable alterations. KW, BC, CS, AD and DW contributed equally. JF, GG and MS contributed equally. Disclosures Rodig: Affimed: Research Funding; KITE: Research Funding; Merck: Research Funding; Bristol Myers Squibb: Research Funding. Shipp:Merck: Research Funding; Bayer: Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Honoraria.
35
Zhuang, Jie, Yonglin Wang, Yonggang Chi, et al. "Drought stress strengthens the link between chlorophyll fluorescence parameters and photosynthetic traits." PeerJ 8 (September 24, 2020): e10046. http://dx.doi.org/10.7717/peerj.10046.
Full textAbstract:
Chlorophyll fluorescence (ChlF) has been used to understand photosynthesis and its response to climate change, particularly with satellite-based data. However, it remains unclear how the ChlF ratio and photosynthesis are linked at the leaf level under drought stress. Here, we examined the link between ChlF ratio and photosynthesis at the leaf level by measuring photosynthetic traits, such as net CO2 assimilation rate (An), the maximum carboxylation rate of Rubisco (Vcmax), the maximum rate of electron transport (Jmax), stomatal conductance (gs) and total chlorophyll content (Chlt). The ChlF ratio of the leaf level such as maximum quantum efficiency of PSII (Fv/Fm) is based on fluorescence kinetics. ChlF intensity ratio (LD685/LD740) based on spectrum analysis was obtained. We found that a combination of the stomatal limitation, non-stomatal limitation, and Chlt regulated leaf photosynthesis under drought stress, while Jmax and Chlt governed the ChlF ratio. A significant link between the ChlF ratio and An was found under drought stress while no significant correlation in the control, which indicated that drought stress strengthens the link between the ChlF ratio and photosynthetic traits. These results suggest that the ChlF ratio can be a powerful tool to track photosynthetic traits of terrestrial ecosystems under drought stress.
36
Minh, T. B., M. S. Prudente, M. Watanabe, et al. "Recent contamination of persistent chlorinated endocrine disrupters in cetaceans from the North Pacific and Asian coastal waters." Water Science and Technology 42, no. 7-8 (2000): 231–40. http://dx.doi.org/10.2166/wst.2000.0574.
Full textAbstract:
To elucidate the global distribution and toxicological impacts of persistent organochlorines (OCs) on cetaceans, the present study determined the concentrations of organochlorine pesticides such as DDT and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), chlordane compounds (CHLs) and PCBs including toxic coplanar congeners in the blubber of 10 species of adult male odontoceti cetaceans collected from several locations in the North Pacific Ocean and coastal waters of Japan, Hong Kong, Philippines and India during 1985–1997. Concentrations of tris(4-chlorophenyl)methane (TCPMe) and tris(4-chlorophenyl)methanol (TCPMOH), which are among the newly identified contaminants, were also determined. Residue pattern was in the order of DDTs≥PCBs&gt;CHLs&gt;HCHs&gt;HCB&gt;TCPMOH&gt;TCPMe. Greater DDT concentrations were found in cetaceans from the Japan Sea, coastal waters of Hong Kong and India, indicating serious marine pollution in industrialized Asian nations and current usage of DDTs in tropical regions. In general, cetaceans inhabiting cold and temperate waters contained relatively higher concentrations of PCBs, HCHs, CHLs and HCB as compared with those from tropical regions, reflecting atmospheric transport from the tropical sources to the northern sinks. Latitudinal distribution of TCPMe and TCPMOH in cetaceans from the North Pacific Ocean and Asian coastal waters was similar to that of DDTs, suggesting the less transportable nature of TCPMe and TCPMOH in the marine environment. Penta- and hexa-chlorobiphenyls were the predominant PCB congeners, accounting for about 70% of the total PCBs. 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) of non- and mono-ortho coplanar PCBs in the blubber of cetaceans ranged from 36 (in spinner dolphin from Philippines) to 510 pg/g wet wt (in hump-backed dolphin from Hong Kong). Toxic evaluation of coplanar PCBs using TEQ concept indicates an increasing impact on cetaceans from mid-latitudes. Mono-ortho congener IUPAC 118 or non-ortho congener IUPAC 126 was estimated to have the greatest toxicity contribution. The estimated TEQ concentrations in the blubber of some cetacean species exceeded the level associated with immunosuppresion in harbour seals.
37
O’Connor, Giselle, Jordi Julvez, Silvia Fernandez-Barrés, et al. "Association of Lifestyle Factors and Neuropsychological Development of 4-Year-Old Children." International Journal of Environmental Research and Public Health 17, no. 16 (2020): 5668. http://dx.doi.org/10.3390/ijerph17165668.
Full textAbstract:
Background: We aimed to assess how lifestyle factors such as diet, sleep, screen viewing, and physical activity, individually, as well as in a combined score, were associated with neuropsychological development in pre-school age children. Methods: We conducted a cross-sectional study in 1650 children of 4 years of age, from the Environment and Childhood Project (INMA) population-based birth cohorts in four regions of Spain. Children were classified per a childhood healthy lifestyle score (CHLS) with a range of 0 to 4 that included eating in concordance with the Mediterranean diet (1 point); reaching recommended sleep time (1 point); watching a maximum recommended screen time (1 point); and being physically active (1 point). The McCarthy Scales of Children’s Abilities (MSCA) were used to test neuropsychological development. Multi-adjusted linear regression models were created to assess the association with the lifestyle factors individually and as a combined score. Results: CHLS was not associated with MSCA general cognitive score (1-point increment = −0.5, 95% CI: −1.2, 0.2). Analyzed by separate lifestyle factors, physical activity had a significant negative association with MSCA score and less TV/screen time had a negative association with MSCA score. Conclusion: In this cross-sectional study, a combined score of lifestyle factors is not related to neuropsychological development at pre-school age.
38
CHAO, Pi-Yu, Meng-Yuan HUANG, Wen-Dar HUANG, Kuan-Hung Robert LIN, Shiau-Ying CHEN, and Chi-Ming YANG. "Study of Chlorophyll-related Compounds from Dietary Spinach in Human Blood." Notulae Botanicae Horti Agrobotanici Cluj-Napoca 46, no. 2 (2018): 309–16. http://dx.doi.org/10.15835/nbha46210918.
Full textAbstract:
Human bioavailability data on chlorophyll (Chl) is very limited. The distribution of Chl-related compounds (CRCs) derived from dietary spinach was investigated in human blood. Eight healthy adults, aged from 21 to 61 year-old, consumed 1.2 kg of just-boiled fresh spinach after an 8-h overnight fast. Before and then 3 h after consuming the spinach, blood samples were taken from each participant. Freeze-dried blood samples were prepared, and 80% acetone was added for grinding. Eight peaks were found in the blood using high-performance liquid chromatography (HPLC), and the main CRCs in the samples were pheophytin (Phe) and pheophorbide (Pho) derivates. Compared to a fasted state, markedly higher levels of blood CRCs were detected in all subjects, except that Pho metabolites were not found in two subjects. No significant differences were seen in most of the peaks between males and females; however, relatively higher CRCs levels were observed in females, particular of Pho derivates. In addition, the blood contained significantly higher levels of Phe in the 36~61-year-old group than in the 21~35-year-old group. These results suggest that the conversion of Chls to CRCs is a rapid process, and Chls obtained by ingestion can be absorbed by the human body.
39
Hao, Yansheng, Bjoern Chapuy, Stefano Monti, Heather Sun, Scott J. Rodig, and Margaret A. Shipp. "Preclinical Analyses Of The Chemical JAK2 Inhibitor, SAR302503, In Classical Hodgkin Lymphoma and Primary Mediastinal Large B-Cell Lymphoma." Blood 122, no. 21 (2013): 4230. http://dx.doi.org/10.1182/blood.v122.21.4230.4230.
Full textAbstract:
Abstract Classical Hodgkin lymphoma (cHL) and primary mediastinal large B-cell lymphoma (MLBCL) are diseases which share certain clinical, pathologic and genetic features. We previously characterized chromosome 9p24 amplification as a disease-specific structural alteration in cHL and MLBCL and identified the immunoregulatory genes, PD-L1 and PD-L2, and JAK2 as key targets of the 9p24 amplification. In a panel of informative cHL and MLBCL cell lines with defined 9p24 copy number, JAK2 amplification increased JAK2 protein expression and activity and enhanced sensitivity to chemical JAK2 inhibition with commercially available tool compounds. Given the importance of JAK/STAT signaling as a survival pathway in primary cHL and MLBCL and the pathway’s additional role in augmenting PD-1 ligand transcription, we postulated that JAK2 was a promising rational therapeutic target in cHLs and MLBCLs with 9p24 amplification. SAR302503 (fedratinib), formerly TG101348, is a selective, potent and oral JAK2 inhibitor that has demonstrated clinical activity in myeloproliferative disorders with activating JAK2 mutations. For these reasons, we have evaluated the preclinical activity of SAR302503 in in vitro and in vivo model systems of cHL and MLBCL with known 9p24/JAK2 copy number. In in vitro analyses, SAR302503 inhibited the cellular proliferation of cHL and MLBCL cell lines and induced their apoptosis. Of note, there was an inverse correlation between 9p24/JAK2 copy number and the EC50 of SAR302503, indicating that cHLs and MLBCLs with JAK2 amplification exhibited increased sensitivity to chemical JAK2 inhibition. In this series of cHLs and MLBCLs of defined JAK2 copy number, JAK2 copy gain was associated with higher baseline phosphorylated JAK2 (pJAK2) and increased abundance of phosphorylated STAT family members including pSTAT1, pSTAT3 and pSTAT6. Consistent with the copy number-dependent anti-proliferative effects of SAR302503, the compound decreased pJAK2, pSTAT1, 3 and 6 in a copy-number dependent manner in cHLs and MLBCLs. These effects were apparent within 2 hours of SAR302503 treatment. We next developed a comprehensive phosphoJAK/STAT immunohistochemical signature to assess baseline pathway activity and sensitivity to targeted chemical JAK2 inhibition. In cHL cell lines with 9p24 amplification, SAR302503 treatment abrogated pJAK2, pSTAT1 and pSTAT3 immunohistochemical staining at early and late timepoints. Furthermore, chemical JAK2 inhibition decreased PD-L1 transcript abundance in 9p24-amplified cHL and MLBCL cell lines and reduced the abundance of downstream JAK2 targets including MYC and PIM1 in cHLs with high JAK2 copy number. After demonstrating the activity and specificity of SAR302503 in in vitro assays, we evaluated the JAK2 inhibitor in murine xenograft models of cHL and MLBCL with 9p24/JAK2 amplification (Karpas 1106 [MLBCL] and HDLM2 [cHL]). In systemic MLBCL (Karpas 1106) and subcutaneous cHL (HDLM2) xenograft models, tumor growth was monitored via bioluminescent imaging (Karpas 1106) and mass measurements (HDLM2) and SAR302503 treatment was begun following the establishment of ≅ 100 mm3 tumors. In both models, pSTAT3 was analyzed as a pharmacodynamic marker following 5 days of treatment and SAR302503-treated animals had markedly decreased tumor cell pSTAT3 expression. In the Karpas 1106 MLBCL murine model, SAR302503 treatment significantly prolonged overall survival (p = .0002). In the HDLM2 cHL xenograft model, the JAK2 inhibitor significantly decreased subcutaneous tumor growth (p< .0001) and pSTAT3 expression in tumor cells (p = .0004). Transcriptional profiling confirmed that the HDLM2 tumors from SAR302503-treated animals exhibited coordinately decreased expression of STAT3 targets and downregulation of a functionally validated JAK2 gene set. Taken together, these data indicate that SAR302503 specifically decreases cHL and MLBCL growth in a 9p24/JAK2 copy number-dependent manner in vitro and in vivo and highlight the utility of pSTAT3 immunohistochemistry as a biomarker of pathway responsiveness. Clinical evaluation of JAK2 pathway inhibition in patients with cHL and MLBCL with known 9p24/JAK2 copy number status is warranted. Disclosures: Hao: Sanofi: Research Funding. Off Label Use: Drug is not yet approved but is being evaluated in myelofibrosis. Shipp:Sanofi: Research Funding.
40
Vesco-Chabert, Sophie, Nina Sydenier, Lucie Legé, Anne Chapet, Marion Nouvel, and Vincent Piriou. "Mise en place d’une revue des erreurs médicamenteuses à l’USC du CHLS." Anesthésie & Réanimation 1 (September 2015): A374—A375. http://dx.doi.org/10.1016/j.anrea.2015.07.572.
Full text
41
Gonzalez-Cascon, Rosario, Leticia Jiménez-Fenoy, Irene Verdú-Fillola, and M. Pilar Martín. "Short communication: Aqueous-acetone extraction improves the drawbacks of using dimethylsulfoxide as solvent for photometric pigment quantification in Quercus ilex leaves." Forest Systems 26, no. 2 (2017): eSC04. http://dx.doi.org/10.5424/fs/2017262-11099.
Full textAbstract:
Aim of study: We evaluated the use of dimethylsulfoxide (DMSO) for the photometric determination of chlorophyll (Chla and Chlb) and carotenoids in Quercus ilex L. leaves by comparative analysis using aqueous-acetone extraction.Area of study: a Q. ilex dehesa in Las Majadas del Tietar, Cáceres, SpainMaterial and methods: Q. ilex leaves were sampled during two vegetative periods. Field SPAD-502 Chlorophyll measurements and photometric chlorophyll determinations were performed. Two procedures were used: extraction of intact foliar discs at 65ºC with DMSO and fine foliar powder with cold aqueous-acetone.Main results: DMSO produced Chlb overestimation and different fitting performance for SPAD vs pigment calibrations (R2=0.64, RMSE=0.20, p<0.0001 for Chla (µg/cm2); R2=0.33, RMSE=0.23, p<0.0001 for Chlb (µg/cm2) and R2=0.50, RMSE=0.23, p<0.0001 for carotenoids (µg/cm2)). Aqueous-acetone provided more accurate predictions (R2=0.90, RMSE=0.16, p<0.0001 for Chla and R2=0.91, RMSE=0.16, p<0.0001 for Chlb, R2=0.90, RMSE=0.02, p<0.0001 for carotenoids) and mean ratio Chla/Chlb=3.6 inside the range for sun exposed leaves.Research highlights: Oxidizing conditions and polyphenol concentrations in Q. ilex leaves generated brown coloration in the DMSO extraction procedure, interfering with the photometric measurements in the red-orange region. Aqueous-acetone extraction was free from interference. DMSO should be avoided for pigment determination in Q. ilex leaves or when comparing different tree species.
42
Byungro Lim and 김세리. "Issues and Possibilities of CHLS(Cyber Home Learning System): Implications on Language Education." Multimedia-Assisted Language Learning 11, no. 1 (2008): 9–33. http://dx.doi.org/10.15702/mall.2008.11.1.9.
Full text
43
Okazawa, Atsushi, Lei Tang, Yoshiko Itoh, Ei’ichiro Fukusaki, and Akio Kobayashi. "Characterization and Subcellular Localization of Chlorophyllase from Ginkgo biloba." Zeitschrift für Naturforschung C 61, no. 1-2 (2006): 111–17. http://dx.doi.org/10.1515/znc-2006-1-220.
Full textAbstract:
Abstract Chlorophyllase (Chlase) catalyzes the initial step of chlorophyll (Chl)-degradation, but the physiological significance of this reaction is still ambiguous. Common understanding of its role is that Chlase is involved in de-greening processes such as fruit ripening, leaf senescence, and flowering. But there is a possibility that Chlase is also involved in turnover and homeostasis of Chls. Among the de-greening processes, autumnal coloration is one of the most striking natural phenomena, but the involvement of Chlase during autumnal coloration is not clear. Previously, it was shown that Chlase activity and expression level of the Chlase gene were not increased during autumnal coloration in Ginkgo biloba, indicating that Chlase does not work specially in the de-greening processes in G. biloba. In this study, we characterized the recombinant Chlase and analyzed its subcellular localization to understand the role of the cloned Chlase of G. biloba (GbCLH). GbCLH exhibited its highest activity at pH 7.5, 40 °C. Kinetic analysis revealed that GbCLH hydrolyzes pheophytin (Pheo) a and Chl a more rapidly than Pheo b and Chl b. Transient expression analysis of 40 N-terminus amino acids of GbCLH fused with GFP (green fluorescent protein) and subcellular fractionation showed that GbCLH localizes within chloroplasts. Together with our previous results, property of GbCLH and its location within the chloroplasts suggest that GbCLH plays a role in the turnover and homeostasis of Chls in green leaves of G. biloba
44
Carey, Christopher Daniel, Courtney Connelly, Evisa Gjini, et al. "Quantitative Assessment of PD-L1 Expression in Classical Hodgkin Lymphoma Suggests a Critical Role for Tumor Associated Macrophages in Suppressing Anti-Tumor Immunity." Blood 126, no. 23 (2015): 1440. http://dx.doi.org/10.1182/blood.v126.23.1440.1440.
Full textAbstract:
Abstract BACKGROUND: The programmed cell death-1 ligands (PD-Ls; PD-L1 and PD-L2) act as negative regulators of anti-tumor immunity by binding their cognate receptor, PD-1, on cytotoxic T-cells and inducing T-cell "exhaustion", a phenotype that is reversible with PD-1 blockade. Human antibodies that block PD-1 induce objective clinical responses in the majority of patients with relapsed / refractory classical Hodgkin Lymphoma (CHL). CHLs include small numbers of malignant Hodgkin Reed-Sternberg (HRS) cells (~5% of total cellularity) within an extensive but ineffective inflammatory and immune cell infiltrate. Over 85% of CHLs express PD-Ls on both the HRS cells and additional non-malignant cells within the tumor microenvironment (Chen et al., CCR 2010). PD-L expression in HRS cells is attributable, in part, to copy gain of chromosome 9p24.1, a region that includes PD-L1, PD-L2, and JAK2 (Green et al., Blood, 2010). However, the contribution of non-malignant cells to the overall PD-L expression within the tumor micro-environment of CHL is poorly defined. METHODS: We analyzed select CHLs (12 EBV+, 8 EBV-) by multiplex immunofluorescence using formalin-fixed, paraffin embedded tissue sections, with successive labeling by primary antibodies (PD-L1, CD30, CD68, pSTAT3, CD163), followed by secondary amplification and tyramide-conjugated fluorophores. For each case 2 large representative areas of tissue, totaling eight 20x fields of view were selected and imaged using a multispectral imaging platform. Two specific image analysis algorithms were designed to accurately identify CD30+ HRS cells and CD68+ macrophages simultaneously, then to threshold PD-L1 by relative fluorescent units (RFU) in each phenotype. Cartesian coordinates for all cells were exported and distance calculations were generated between PD-L1+ and PD-L1- macrophages and their Ônearest neighborÕ CD30+ PD-L1+ HRS cell. RESULTS: The percentages of CD30+ HRS cells and CD68+ macrophages expressing PD-L1 was highly variable across cases (range 9 - 94%, median 46.6% for HRS cells; range 6 - 91.3%, median 48.2% for macrophages). In all cases the majority of PD-L1 protein within the tumor micro-environment was contributed by macrophages (median 77.9%, range 50.4 - 98.5%), although the mean relative intensity of PD-L1 per cell was higher for HRS cells than for macrophages (3.13 +/-0.02 RFU vs 2.85 +/- 0.01 RFU; p < 0.0001 by Welch t-test). Further analysis revealed that the percentage of HRS cells and macrophages expressing PD-L1 was highly correlated (Pearson r = 0.67; 95% CI 0.32 - 0.85; p=0.001) and, in 18/20 tumors, PD-L1+ macrophages were in greater proximity to PD-L1+ HRS cells than PD-L1- macrophages (across 20 cases mean distance of 32.6 µm (SE 5 µm) versus 51.2 µm (SE 6.8 µm), respectively; p < 0.05). CONCLUSIONS: CD68+ tumor-associated macrophages (TAMs) express the majority of PD-L1 in CHLs, which contain rare tumor cells. Image analysis of the distribution of PD-L1 in the tumor microenvironment indicates that PD-L1+ TAMs are significantly enriched in proximity to PD-L1+ HRS cells. These data implicate HRS cells in coordinating PD-L1 induction among TAMs to limit anti-tumor immunity. Figure 1. Figure 1. Disclosures Shipp: Merck: Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Research Funding. Rodig:Perkin Elmer: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Research Funding.
45
Gao, Yang, Wei Xiong, Ming J. He, Li Tang, Jin Y. Xiang, and Qing Y. Wu. "Action Spectra of Chlorophyll a Biosynthesis in Cyanobacteria: Dark-Operative Protochlorophyllide Oxidoreductase-Deficient Mutants." Zeitschrift für Naturforschung C 64, no. 1-2 (2009): 117–24. http://dx.doi.org/10.1515/znc-2009-1-219.
Full textAbstract:
Both light-dependent and light-independent (dark) protochlorophyllide (Pchlide) reductase account for catalyzing the reduction of Pchlide to chlorophyllide during the biosynthesis of Mg-tetrapyrrole pigments in cyanobacteria. To gain more insight into the interaction between the wavelength of the light and these two chlorophyll synthetic pathways in Synechocystis sp. PCC 6803, the spectral effectiveness of the formation of chlorophyll a was investigated during the regreening process in chlL- and chlN- mutants, which could not synthesize chlorophyll during growth in the dark. The action spectra showed obvious maxima around 450 nm and 650 nm, similar to those of higher plants except that the intensities of two peaks are reversed. The mRNA levels of chlL and chlN and chlorophyll a content under different wavelengths of light in the wild-type strain were also measured. The RT-PCR analysis revealed that the transcripts of chlL and chlN were up-regulated in red light but simultaneously down-regulated in green light which resulted in corresponding changes of the chlorophyll content. This fact indicates that the regulation of dark-operative protochlorophyllide oxidoreductase (DPOR) in the transcriptional level is essential for cyanobacteria to synthesize appropriate chlorophyll for acclimating in various light colour environments.
46
Bhuvaneshwari, R., and R. Babu Rajendran. "GCMS Determination of Organochlorine Pesticides (OCPs) in Fish from River Cauvery and Veeranam Lake." E-Journal of Chemistry 9, no. 4 (2012): 2346–53. http://dx.doi.org/10.1155/2012/395707.
Full textAbstract:
Organochlorine Pesticides (OCPs) were analyzed using Gas Chromatography-Mass Spectrometer (Selective Ion Monitoring mode) in the muscle tissues of five fish species such asO. mossambicus, L. parsia, E. suretensis, C. striata and S. wynaadensisfrom seven locations of River Cauvery and one location in Veeranam Lake. OCPs viz., DDTs, HCHs, CHLs, cyclodienes, heptachlor, HCB and mirex were detected with varying concentrations among species and locations. Mirex which was not reported in the fish tissues elsewhere reported in this study. The study on the risk associated with the consumption of fish species that had higher concentrations of aldrin, dieldrin and mirex showed significant carcinogenic risk to the human beings.
47
YUAN YUAN. "Common Errors Committed by Korean Students in Learning “zhidao” Category of Verbs of the Chinese Language and Teaching Strategies for Korean Students." Journal of Chinese Language and Literature ll, no. 75 (2016): 143–67. http://dx.doi.org/10.26586/chls.2016..75.006.
Full text
48
Shin Hyun chur, 홍승직, and 기호철. "Taxonomic Identity of Chinese Letter Chu in Shijing and Its Korean Translation." Journal of Chinese Language and Literature ll, no. 75 (2016): 169–202. http://dx.doi.org/10.26586/chls.2016..75.007.
Full text
49
최석원 and 김보경. "Southern Song Dynasty Literati’s Understanding of the Three Kingdoms History." Journal of Chinese Language and Literature ll, no. 75 (2016): 203–28. http://dx.doi.org/10.26586/chls.2016..75.008.
Full text
50
홍성초. "The Significance of The Temporal Scene and Composition Method in the Journey to The West (≪西游记≫)". Journal of Chinese Language and Literature ll, № 75 (2016): 229–49. http://dx.doi.org/10.26586/chls.2016..75.009.
Full text