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ERMAN DALOĞLU, Aylin, Derya MUTLU, İmran SAĞLIK, et al. "Evaluation of the Two Different Real Time Polymerase Chain Reaction Methods Used for BK Virus (BKV) Quantification and BKV Genotype Assignment." Mikrobiyoloji Bulteni 53, no. 3 (2019): 285–96. http://dx.doi.org/10.5578/mb.68059.
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Wu, Ying, and Xim-Xue Yang. "Chain Solutions of the BKP Equation." Communications in Theoretical Physics 23, no. 1 (1995): 121–24. http://dx.doi.org/10.1088/0253-6102/23/1/121.
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Singh, Vineet K., Dipti S. Hattangady, Efstathios S. Giotis та ін. "Insertional Inactivation of Branched-Chain α-Keto Acid Dehydrogenase in Staphylococcus aureus Leads to Decreased Branched-Chain Membrane Fatty Acid Content and Increased Susceptibility to Certain Stresses". Applied and Environmental Microbiology 74, № 19 (2008): 5882–90. http://dx.doi.org/10.1128/aem.00882-08.
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ABSTRACT Staphylococcus aureus is a major community and nosocomial pathogen. Its ability to withstand multiple stress conditions and quickly develop resistance to antibiotics complicates the control of staphylococcal infections. Adaptation to lower temperatures is a key for the survival of bacterial species outside the host. Branched-chain α-keto acid dehydrogenase (BKD) is an enzyme complex that catalyzes the early stages of branched-chain fatty acid (BCFA) production. In this study, BKD was inactivated, resulting in reduced levels of BCFAs in the membrane of S. aureus. Growth of the BKD-inactivated mutant was progressively more impaired than that of wild-type S. aureus with decreasing temperature, to the point that the mutant could not grow at 12�C. The growth of the mutant was markedly stimulated by the inclusion of 2-methylbutyrate in the growth medium at all temperatures tested. 2-Methylbutyrate is a precursor of odd-numbered anteiso fatty acids and bypasses BKD. Interestingly, growth of wild-type S. aureus was also stimulated by including 2-methylbutyrate in the medium, especially at lower temperatures. The anteiso fatty acid content of the BKD-inactivated mutant was restored by the inclusion of 2-methylbutyrate in the medium. Fluorescence polarization measurements indicated that the membrane of the BKD-inactivated mutant was significantly less fluid than that of wild-type S. aureus. Consistent with this result, the mutant showed decreased toluene tolerance that could be increased by the inclusion of 2-methylbutyrate in the medium. The BKD-inactivated mutant was more susceptible to alkaline pH and oxidative stress conditions. Inactivation of the BKD enzyme complex in S. aureus also led to a reduction in adherence of the mutant to eukaryotic cells and its survival in a mouse host. In addition, the mutant offers a tool to study the role of membrane fluidity in the interaction of S. aureus with antimicrobial substances.
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Buchert, Felix, Laura Mosebach, Philipp Gäbelein, and Michael Hippler. "PGR5 is required for efficient Q cycle in the cytochrome b6f complex during cyclic electron flow." Biochemical Journal 477, no. 9 (2020): 1631–50. http://dx.doi.org/10.1042/bcj20190914.
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Proton gradient regulation 5 (PGR5) is involved in the control of photosynthetic electron transfer, but its mechanistic role is not yet clear. Several models have been proposed to explain phenotypes such as a diminished steady-state proton motive force (pmf) and increased photodamage of photosystem I (PSI). Playing a regulatory role in cyclic electron flow (CEF) around PSI, PGR5 contributes indirectly to PSI protection by enhancing photosynthetic control, which is a pH-dependent down-regulation of electron transfer at the cytochrome b6f complex (b6f). Here, we re-evaluated the role of PGR5 in the green alga Chlamydomonas reinhardtii and conclude that pgr5 possesses a dysfunctional b6f. Our data indicate that the b6f low-potential chain redox activity likely operated in two distinct modes — via the canonical Q cycle during linear electron flow and via an alternative Q cycle during CEF, which allowed efficient oxidation of the low-potential chain in the WT b6f. A switch between the two Q cycle modes was dependent on PGR5 and relied on unknown stromal electron carrier(s), which were a general requirement for b6f activity. In CEF-favoring conditions, the electron transfer bottleneck in pgr5 was the b6f, in which insufficient low-potential chain redox tuning might account for the mutant pmf phenotype. By attributing a ferredoxin-plastoquinone reductase activity to the b6f and investigating a PGR5 cysteine mutant, a current model of CEF is challenged.
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Andini, Enggartya, Sudarno Sudarno, and Rita Rahmawati. "PENERAPAN METODE PENGENDALIAN KUALITAS MEWMA BERDASARKAN ARL DENGAN PENDEKATAN RANTAI MARKOV (Studi Kasus: Batik Semarang 16, Meteseh)." Jurnal Gaussian 10, no. 1 (2021): 125–35. http://dx.doi.org/10.14710/j.gauss.v10i1.30939.
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An industrial company requires quality control to maintain quality consistency from the production results so that it is able to compete with other companies in the world market. In the industrial sector, most processes are influenced by more than one quality characteristic. One tool that can be used to control more than one quality characteristic is the Multivariate Exponentially Weighted Moving Average (MEWMA) control chart. The graph is used to determine whether the process has been controlled or not, if the process is not yet controlled, the next analysis that can be used is to use the Average Run Length (ARL) with the Markov Chain approach. The markov chain is the chance of today's event is only influenced by yesterday's incident, in this case the chance of the incident in question is the incident in getting a sampel of data on the production process of batik cloth to get a product that is in accordance with the company standards. ARL is the average number of sample points drawn before a point indicates an uncontrollable state. In this study, 60 sample data were used which consisted of three quality characteristics, namely the length of the cloth, the width of the cloth, and the time of the fabric for the production of written batik in Batik Semarang 16 Meteseh. Based on the results and discussion that has been done, the MEWMA controller chart uses the λ weighting which is determined using trial and error. MEWMA control chart can not be said to be stable and controlled with λ = 0.6, after calculating, the value is obtained Upper Control Limit (BKA) of 11.3864 and Lower Control Limit (BKB) of 0. It is known that from 60 data samples there is a Tj2 value that comes out from the upper control limit (BKA) where the amount of 15.70871, which indicates the production process is not controlled statistically. Improvements to the MEWMA controller chart can be done based on the ARL with the Markov Chain approach. In this final project, the ARL value used is 200, the magnitude of the process shift is 1.7 and the r value is 0.28, where the value of r is a constant obtained on the r parameter graph. The optimal MEWMA control chart based on ARL with the Markov Chain approach can be said to be stable and controlled if there is no Tj2 value that is outside the upper control limit (BKA). The results of the MEWMA control chart based on the ARL with the Markov Chain approach show that the process is not statistically capable because the MCpm value is 0.516797 and the MCpmk value is 0.437807, the value indicates a process capability index value of less than 1. Keywords: Handmade batik, Multivariate Exponentially Weighted Moving Average (MEWMA), Average Run Length (ARL), Capability process.
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Sun, Yvonne, and Mary X. D. O'Riordan. "Branched-Chain Fatty Acids Promote Listeria monocytogenes Intracellular Infection and Virulence." Infection and Immunity 78, no. 11 (2010): 4667–73. http://dx.doi.org/10.1128/iai.00546-10.
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ABSTRACT Anteiso-branched-chain fatty acids (BCFA) represent the dominant group of membrane fatty acids and have been established as crucial determinants in resistance against environmental stresses in Listeria monocytogenes, a facultative intracellular pathogen. Here, we investigate the role of anteiso-BCFA in L. monocytogenes virulence by using mutants deficient in branched-chain alpha-keto acid dehydrogenase (BKD), an enzyme complex involved in the synthesis of BCFA. In tissue culture models of infection, anteiso-BCFA contributed to intracellular growth and survival in macrophages and significantly enhanced plaque formation upon prolonged infection in L2 fibroblasts. The intracellular defects observed could be attributed partially to insufficient listeriolysin O (LLO) production, indicating a requirement for anteiso-BCFA in regulating virulence factor production. In a murine model of infection, the BKD-deficient mutant was highly attenuated, further emphasizing the importance of BKD-mediated metabolism in L. monocytogenes virulence. This study demonstrates an underappreciated role for BCFA in bacterial pathogenesis, which may provide insight into the development and application of antimicrobial agents.
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Zhou, M. D., S. K. Goswami, M. E. Martin, and M. A. Siddiqui. "A new serum-responsive, cardiac tissue-specific transcription factor that recognizes the MEF-2 site in the myosin light chain-2 promoter." Molecular and Cellular Biology 13, no. 2 (1993): 1222–31. http://dx.doi.org/10.1128/mcb.13.2.1222.
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We have identified a serum-responsive, cardiac tissue-specific transcription factor, BBF-1, that recognizes an AT-rich sequence (element B), identical to the myocyte enhancer factor (MEF-2) target site, in the cardiac myosin light chain-2 (MLC-2) promoter. Deletion of the element B sequence alone from the cardiac MLC-2 promoter causes, as does that of the MEF-2 site from other promoters and the enhancer of skeletal muscle genes, a marked reduction of transcription. BBF-1 is distinguishable from cardiac MEF-2 on the basis of immunoprecipitation with an antibody which recognizes MEF-2 but not BBF-1. Unlike MEF-2, BBF-1 is present exclusively in nuclear extracts from cardiac muscle cells cultured in a medium containing a high concentration of serum. Removal of serum from culture medium abolishes BBF-1 activity selectively with a concomitant loss of the positive regulatory effect of element B on MLC-2 gene transcription, indicating that there is a correlation between the BBF-1 binding activity and the tissue-specific role of the element B (MEF-2 site) sequence. The loss of element B-mediated activation of transcription is reversed following the refeeding of cells with serum-containing medium. These data demonstrate that cardiac muscle cells contain two distinct protein factors, MEF-2 and BBF-1, which bind to the same target site but that, unlike MEF-2, BBF-1 is serum inducible and cardiac tissue specific. BBF-1 thus appears to be a crucial member of the MEF-2 family of proteins which will serve as an important tool in understanding the regulatory mechanism(s) underlying cardiogenic differentiation.
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Zhou, M. D., S. K. Goswami, M. E. Martin, and M. A. Siddiqui. "A new serum-responsive, cardiac tissue-specific transcription factor that recognizes the MEF-2 site in the myosin light chain-2 promoter." Molecular and Cellular Biology 13, no. 2 (1993): 1222–31. http://dx.doi.org/10.1128/mcb.13.2.1222-1231.1993.
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We have identified a serum-responsive, cardiac tissue-specific transcription factor, BBF-1, that recognizes an AT-rich sequence (element B), identical to the myocyte enhancer factor (MEF-2) target site, in the cardiac myosin light chain-2 (MLC-2) promoter. Deletion of the element B sequence alone from the cardiac MLC-2 promoter causes, as does that of the MEF-2 site from other promoters and the enhancer of skeletal muscle genes, a marked reduction of transcription. BBF-1 is distinguishable from cardiac MEF-2 on the basis of immunoprecipitation with an antibody which recognizes MEF-2 but not BBF-1. Unlike MEF-2, BBF-1 is present exclusively in nuclear extracts from cardiac muscle cells cultured in a medium containing a high concentration of serum. Removal of serum from culture medium abolishes BBF-1 activity selectively with a concomitant loss of the positive regulatory effect of element B on MLC-2 gene transcription, indicating that there is a correlation between the BBF-1 binding activity and the tissue-specific role of the element B (MEF-2 site) sequence. The loss of element B-mediated activation of transcription is reversed following the refeeding of cells with serum-containing medium. These data demonstrate that cardiac muscle cells contain two distinct protein factors, MEF-2 and BBF-1, which bind to the same target site but that, unlike MEF-2, BBF-1 is serum inducible and cardiac tissue specific. BBF-1 thus appears to be a crucial member of the MEF-2 family of proteins which will serve as an important tool in understanding the regulatory mechanism(s) underlying cardiogenic differentiation.
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Cropp, T. Ashton, Adam A. Smogowicz, Edmund W. Hafner, Claudio D. Denoya, Hamish AI McArthur та Kevin A. Reynolds. "Fatty-acid biosynthesis in a branched-chain α-keto acid dehydrogenase mutant ofStreptomyces avermitilis". Canadian Journal of Microbiology 46, № 6 (2000): 506–14. http://dx.doi.org/10.1139/w00-028.
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Fatty-acid biosynthesis by a branched-chain alpha-keto acid dehydrogenase (bkd) mutant of Streptomyces avermitilis was analyzed. This mutant is unable to produce the appropriate precursors of branched-chain fatty acid (BCFA) biosynthesis, but unlike the comparable Bacillus subtilis mutant, was shown not to have an obligate growth requirement for these precursors. The bkd mutant produced only straight-chain fatty acids (SCFAs) with membrane fluidity provided entirely by unsaturated fatty acids (UFAs), the levels of which increased dramatically compared to the wild-type strain. The levels of UFAs increased in both the wild-type and bkd mutant strains as the growth temperature was lowered from 37°C to 24°C, suggesting that a regulatory mechanism exists to alter the proportion of UFAs in response either to a loss of BCFA biosynthesis, or a decreased growth temperature. No evidence of a regulatory mechanism for BCFAs was observed, as the types of these fatty acids, which contribute significantly to membrane fluidity, did not alter when the wild-type S. avermitilis was grown at different temperatures. The principal UFA produced by S. avermitilis was shown to be delta9-hexadecenoate, the same fatty acid produced by Escherichia coli. This observation, and the inability of S. avermitilis to convert exogenous labeled palmitate to the corresponding UFA, was shown to be consistent with an anaerobic pathway for UFA biosynthesis. Incorporation studies with theS. avermitilis bkd mutant demonstrated that the fatty acid synthase has a remarkably broad substrate specificity and is able to process a wide range of exogenous branched chain carboxylic acids into unusual BCFAs.Key words: Streptomyces avermitilis, fatty acid biosynthesis, avermectin.
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Zhu, Kun, Darrell O. Bayles, Anming Xiong, R. K. Jayaswal та Brian J. Wilkinson. "Precursor and temperature modulation of fatty acid composition and growth of Listeria monocytogenes cold-sensitive mutants with transposon-interrupted branched-chain α-keto acid dehydrogenase". Microbiology 151, № 2 (2005): 615–23. http://dx.doi.org/10.1099/mic.0.27634-0.
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Branched-chain fatty acids (BCFAs) typically constitute more than 90 % of the fatty acids of Listeria monocytogenes. The authors have previously described two Tn917-induced, cold-sensitive, BCFA-deficient (<40 %) L. monocytogenes mutants (cld-1 and cld-2) with lowered membrane fluidity. Sequence analyses revealed that Tn917 was inserted into different genes of the branched-chain α-keto acid dehydrogenase cluster (bkd) in these two mutants. The cold-sensitivity and BCFA deficiency of cld-1, in which Tn917 was inserted into bkdB, were complemented in trans by cloned bkdB. The growth and corresponding BCFA content of the mutants at 37 °C were stimulated by fatty acid precursors bypassing Bkd, 2-methylbutyrate (precursor for odd-numbered anteiso-fatty acids), isobutyrate (precursor for even-numbered iso-fatty acids) and isovalerate (precursor for odd-numbered iso-fatty acids). In contrast, the corresponding Bkd substrates, α-ketomethylvalerate, α-ketoisovalerate and α-ketoisocaproate, exhibited much poorer activity. At 26 °C, 2-methylbutyrate and isovalerate stimulated the growth of the mutants, and at 10 °C, only 2-methylbutyrate stimulated growth. Pyruvate depressed the BCFA content of cld-2 from 33 % to 27 %, which may be close to the minimum BCFA requirement for L. monocytogenes. The transcription of bkd was enhanced by Bkd substrates, but not by low temperature. When provided with the BCFA precursors, cld-2 was able to increase its anteiso-C15 : 0 fatty acid content at 10 °C compared to 37 °C, which is the characteristic response of L. monocytogenes to low temperature. This implies that Bkd is not the major cold-regulation point of BCFA synthesis.
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King-Díaz, Beatriz, Nórah Barba-Behrens, Josefina Montes-Ayala, et al. "Interference by Nickel(II) Salts and Their 5-Methylimidazole-4-carboxylate Coordination Compounds on the Chloroplast Redox Chain." Zeitschrift für Naturforschung C 53, no. 11-12 (1998): 987–94. http://dx.doi.org/10.1515/znc-1998-11-1209.
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Abstract Nickel(II) salts and their coordination com pounds with ethyl 5-m ethylim idazole-4-carboxylate (emizco), [Ni(emizco)2Cl2], [Ni(emizco)2Br2], [Ni(emizco)2(H2O)2] (NO3)2 H2O · Ni(NO3)2, inhibit photosynthetic electron flow (basal, phosphorylating and uncoupled) and ATP-synthesis, therefore behave as Hill reaction inhibitors. Coordination compounds are more potent inhibitors than the salts. It was found that the target for NiCl2; NiBr2 and Ni(NO3)2 is at the b6f level. On the other hand, the complexes [Ni(Emizco)2Cl2], [Ni(Emizco)2Br2] and [Ni(emizco)2(H2O )2] (NO3)2H2O binding sites are located at QB(D1)-protein and b6f level. Therefore, they have a common inhibition site located at b6f avoiding the PQH2 oxidation. The QB inhibition site was corroborated by variable chlorophyll a fluorescence yield [V(j)]. The emizco ligand has no activity on photosynthetic electron flow.
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Zhou, En-Long, Chao Qin, Dan Tian, et al. "A difunctional metal–organic framework with Lewis basic sites demonstrating turn-off sensing of Cu2+ and sensitization of Ln3+." Journal of Materials Chemistry C 6, no. 29 (2018): 7874–79. http://dx.doi.org/10.1039/c8tc02425a.
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Bascands, J. L., M. E. Marin Castaño, G. Bompart, C. Pecher, M. Gaucher, and J. P. Girolami. "Postnatal maturation of the Kallikrein-kinin system in the rat kidney: from enzyme activity to receptor gene expression." Journal of the American Society of Nephrology 7, no. 1 (1996): 81–89. http://dx.doi.org/10.1681/asn.v7181.
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During the course of aging, the balance between intrarenal hormones is disturbed. These age-related changes are well documented for the vasoconstrictor renin-angiotensin system, but comparable information on the renal kallikrein-kinin system is not yet available. The status of the kallikrein-kinin system was assessed by (1) kallikrein activity, measured by RIA; (2) maximum binding site density (Bmax) and affinity (Kd) of nonapeptide bradykinin (BK)-2 receptor, estimated by binding assays; (3) expression of BK2-receptor receptor mRNA, detected by reverse transcription-polymerase chain reaction (RT-PCR) using specific BK2-oligonucleotide primers. These parameters were determinated on renal glomeruli of 3-, 5-, 8-, 12- and 38-wk-old normotensive rats. Kallikrein activity increased from 3.2 to 7.7 ng BK/min per mg protein. The density of BK2 binding sites also rose from 12 to 40 femtomoles/mg protein with no difference in affinity. There was no change in specificity, which remained that expected of a BK2 receptor. The increase in the density of BK2 binding sites was associated with an augmented mRNA expression, whereas beta-actin mRNA used as a control remained unchanged. The ratio of BK2 mRNA to beta-actin mRNA indicated maximum steady expression after 8 wk of age. The data provide evidence that the renal kallikrein-kinin system develops postnatally.
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Hester, Kathryn L., K. T. Madhusudhan, and John R. Sokatch. "Catabolite Repression Control by Crc in 2xYT Medium Is Mediated by Posttranscriptional Regulation of bkdR Expression in Pseudomonas putida." Journal of Bacteriology 182, no. 4 (2000): 1150–53. http://dx.doi.org/10.1128/jb.182.4.1150-1153.2000.
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ABSTRACT The effect of growth in 2xYT medium on catabolite repression control in Pseudomonas putida has been investigated using the bkd operon, encoding branched-chain keto acid dehydrogenase. Crc (catabolite repression control protein) was shown to be responsible for repression of bkd operon transcription in 2xYT. BkdR levels were elevated in a P. putida crcmutant, but bkdR transcript levels were the same in both wild type and crc mutant. This suggests that the mechanism of catabolite repression control in rich media by Crc involves posttranscriptional regulation of the bkdR message.
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Kawahara, A., Y. Minami, and T. Taniguchi. "Evidence for a critical role for the cytoplasmic region of the interleukin 2 (IL-2) receptor gamma chain in IL-2, IL-4, and IL-7 signalling." Molecular and Cellular Biology 14, no. 8 (1994): 5433–40. http://dx.doi.org/10.1128/mcb.14.8.5433.
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The high-affinity interleukin 2 receptor (IL-2R) consists of at least three distinct subunits: the IL-2R alpha chain (IL-2R alpha), beta chain (IL-2R beta), and gamma chain (IL-2R gamma). It has been shown that the cytoplasmic region of IL-2R beta, but not of IL-2R alpha, is essential for IL-2 signalling to the cell interior. In the present study, we examined the functional role of the IL-2R gamma cytoplasmic region in the IL-3-dependent mouse hematopoietic cell line BAF-B03, which expresses the endogenous IL-2R alpha and IL-2R gamma, or its subline F7, which additionally expresses human IL-2R beta cDNA. We show that overexpression of a mutant IL-2R gamma, lacking all but 7 amino acids of its cytoplasmic region, results in the selective inhibition of IL-2-induced c-fos gene activation and cellular proliferation in F7 cells. When two chimeric receptor molecules in which the cytoplasmic regions of IL-2R beta and IL-2R gamma had been swapped with each other (IL-2R beta/gamma and IL-2R gamma/beta) were coexpressed in BAF-B03, the cells responded to IL-2. These results indicate the critical importance of the IL-2-induced functional cooperation of the two cytoplasmic regions. Finally, we provide evidence that the IL-2R gamma cytoplasmic region is also critical for the IL-4 and IL-7-induced growth signal transduction in BAF-B03.
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Kawahara, A., Y. Minami, and T. Taniguchi. "Evidence for a critical role for the cytoplasmic region of the interleukin 2 (IL-2) receptor gamma chain in IL-2, IL-4, and IL-7 signalling." Molecular and Cellular Biology 14, no. 8 (1994): 5433–40. http://dx.doi.org/10.1128/mcb.14.8.5433-5440.1994.
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The high-affinity interleukin 2 receptor (IL-2R) consists of at least three distinct subunits: the IL-2R alpha chain (IL-2R alpha), beta chain (IL-2R beta), and gamma chain (IL-2R gamma). It has been shown that the cytoplasmic region of IL-2R beta, but not of IL-2R alpha, is essential for IL-2 signalling to the cell interior. In the present study, we examined the functional role of the IL-2R gamma cytoplasmic region in the IL-3-dependent mouse hematopoietic cell line BAF-B03, which expresses the endogenous IL-2R alpha and IL-2R gamma, or its subline F7, which additionally expresses human IL-2R beta cDNA. We show that overexpression of a mutant IL-2R gamma, lacking all but 7 amino acids of its cytoplasmic region, results in the selective inhibition of IL-2-induced c-fos gene activation and cellular proliferation in F7 cells. When two chimeric receptor molecules in which the cytoplasmic regions of IL-2R beta and IL-2R gamma had been swapped with each other (IL-2R beta/gamma and IL-2R gamma/beta) were coexpressed in BAF-B03, the cells responded to IL-2. These results indicate the critical importance of the IL-2-induced functional cooperation of the two cytoplasmic regions. Finally, we provide evidence that the IL-2R gamma cytoplasmic region is also critical for the IL-4 and IL-7-induced growth signal transduction in BAF-B03.
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Bevilacqua, M. A., M. C. Faniello, P. D′Agostino, et al. "Transcriptional activation of the H-ferritin gene in differentiated Caco-2 cells parallels a change in the activity of the nuclear factor Bbf." Biochemical Journal 311, no. 3 (1995): 769–73. http://dx.doi.org/10.1042/bj3110769.
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In this paper, we examine the mechanisms that regulate the expression of the heavy (H) ferritin subunit in the colon carcinoma Caco-2 cell line allowed to differentiate spontaneously in vitro. The differentiation process of these cells in continuous culture is accompanied by an accumulation of the mRNA coding for the apoferritin H chain. The analysis of Caco-2 subclones stably transfected with an H-chain promoter-chloramphenicol acetyltransferase (CAT) construct revealed that the mRNA increase is paralleled by an enhanced transcription of the H gene, driven by the -100 to +4 region of the H promoter. The H gene transcriptional activation seems to be a specific feature of differentiated Caco-2 cells, since the activity of other promoters did not change upon differentiation. The -100 to +4 region of the H promoter binds a transcription factor called Bbf (B-box binding factor); electrophoretic-mobility-shift-assay analyses showed that the retarded complex due to Bbf-H promoter interaction is significantly increased in the differentiated cells. We propose that the activation of H-ferritin gene expression may be associated with the establishment of a differentiated phenotype in Caco-2 cells, and that the H-ferritin gene transcriptional up-regulation is accompanied by a modification in the activity of the transcription factor Bbf.
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Moyers, Julie S., Ryan J. Hansen, Jonathan W. Day, et al. "Preclinical Characterization of Once Weekly Basal Insulin Fc (BIF)." Journal of the Endocrine Society 5, Supplement_1 (2021): A442. http://dx.doi.org/10.1210/jendso/bvab048.903.
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Abstract Weekly basal insulin injections may increase treatment adherence in subjects with diabetes and an appropriately engineered weekly basal insulin may reduce daily pharmacokinetic (PK)/pharmacodynamic (PD) fluctuations compared to currently available daily basal insulins. Therefore, a weekly insulin has the potential to not only ease the burden of insulin therapy, but also improve outcomes for subjects with diabetes in a real-world setting. Basal insulin Fc (BIF, LY3209590) is an insulin Fc-fusion protein in clinical testing as a once weekly treatment for type 1 and type 2 diabetes mellitus (T1DM, T2DM). BIF is comprised of a human single-chain insulin fused to a human IgG2 Fc domain through a peptide linker. The in vitro evaluation determined that BIF exhibited reduced insulin receptor (IR) potency with full agonism, selectivity against human insulin-like growth factor-1 receptor (hIGF-1R), and functional properties similar to native human insulin. The binding affinity of BIF for hIR isoform A, Ki = 25 nM (SEM = 4, n=10), and hIR isoform B, Ki = 26 nM (SEM = 4, n=10), was more than two orders of magnitude weaker than human insulin. BIF stimulated IR phosphorylation in cells with reduced potency, but full agonism, and showed a significantly faster hIR dephosphorylation profile than either human insulin or AspB10 insulin. BIF stimulated de novo lipogenesis in 3T3-L1 adipocytes and cell proliferation in SAOS-2 and H4IIE cells with at least a 70-fold reduction in potency compared to human insulin. BIF possessed markedly reduced binding and activation of hIGF-1R making definitive mitogenic measurements unattainable. In preclinical in vivo pharmacology studies using streptozotocin (STZ)-treated diabetic rats, a statistically significant decrease in blood glucose compared to vehicle-treated animals was seen 24 hours post-injection and persisted through 336 hours post-injection following a single subcutaneous administration (30 nmol/kg) of BIF. In STZ-treated rats, BIF reached a Tmax at 48 hours, possessed an apparent clearance rate of ~0.85 mL/hr/kg, and t1/2 of ~120 hrs. Collectively, these results demonstrate that BIF possesses selective IR agonism with a pharmacological profile similar to native insulin, however with a significantly reduced potency, and a significantly extended time action profile in preclinical animal models supporting once weekly testing in the clinic.
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Zhang, Chen, Luo, et al. "Effects of Temperature on the Characteristics of Nitrogen Removal and Microbial Community in Post Solid-Phase Denitrification Biofilter Process." International Journal of Environmental Research and Public Health 16, no. 22 (2019): 4466. http://dx.doi.org/10.3390/ijerph16224466.
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In order to solve the problems of high energy consumption, complex process and low nitrogen removal efficiency in the currently available low carbon source wastewater treatment processes, a novel coagulation sedimentation/post-solid-phase denitrification biofilter process (CS-BAF-SPDB) was proposed. The effect of temperature on the nitrogen removal performance of BAF-SPDB was intensively studied, and the mechanism of the effect of temperature on nitrogen removal performance was analyzed from the perspective of microbial community structure by using the polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that, to realize favorable nitrifying and denitrifying performance simultaneously in the BAF-SPDB unit, the operation temperature should be set above 18 °C. In addition, the influence of the macro operation parameters on the performance of the BAF and SPDB has a direct relationship with the dynamic changes of the micro microbial community. The influence of temperature on nitrification performance in BAF was mainly embodied in the change of composition, amount and activity of ammonia oxidizing bacteria Candidatus Nitrospira defluvii and nitrite oxidizing bacteria Nitrosomonas sp. Nm47, while that on denitrification performance in SPDB is mainly embodied in the change of composition and amount of solid carbon substrate degrading denitrifying bacteria Pseudomonas sp., Myxobacterium AT3-03 and heterotrophic denitrifying bacteria Dechloromonas agitate, Thauera aminoaromatica, Comamonas granuli and Rubrivivax gelatinosus.
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Born, Ella J., Sara V. Hollins, and Sarah A. Holstein. "Evaluation of Autophagy Modulators and Isoprenoid Biosynthetic Pathway Inhibitors in Multiple Myeloma Cells." Blood 118, no. 21 (2011): 2488. http://dx.doi.org/10.1182/blood.v118.21.2488.2488.
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Abstract Abstract 2488 The production of monoclonal protein (MP) by malignant plasma cells is a hallmark of multiple myeloma (MM). We have previously demonstrated that select inhibitors of the isoprenoid biosynthetic pathway (IBP) which diminish Rab geranylgeranylation, disrupt MP trafficking in MM cells. The resulting intracellular accumulation of MP leads to induction of the unfolded protein response (UPR) pathway and apoptosis. The proteasome-mediated ER-associated degradation pathway has been shown to play an important role in intracellular degradation of monoclonal protein. Autophagy, another cellular process by which proteins are degraded, has been shown to play a role in clearing toxic aggregrated proteins in other systems. The extent to which autophagy is involved in clearing accumulated intracellular MP is unknown. We hypothesized that disruption of autophagy may enhance the cytotoxic effects of agents which impair MP trafficking. We therefore evaluated the effects of combining IBP and autophagy inhibitors in MM cells. Studies were performed in the lambda-light chain secreting RPMI-8226 (RPMI) MM line and the amyloidogenic lambda light chain-secreting ALMC-2 line. IBP inhibitors (IBPIs) included lovastatin (Lov) (HMG-CoA reductase inhibitor), digeranyl bisphosphonate (DGBP) (geranylgeranyl diphosphate synthase inhibitor), and 3-PEHPC (3P) (geranylgeranyl transferase II inhibitor). Autophagy modulators included bafilomycin A (Baf), 3-methyladenine (3-MA), and chloroquine (Chl). MTT cytotoxicity assays demonstrated differential effects when IBP and autophagy inhibitors were combined. Isobologram analysis revealed a synergistic interaction between Lov and Baf while predominantly additive or antagonistic interactions were observed with the combination of Lov and 3MA. A primarily additive interaction was observed between DGBP and Baf in the RPMI cells, while a synergistic effect was observed in the ALMC-2 cells. While concurrent incubation between 3P and Baf resulted in an additive interaction, pre-treatment with 3P for 24 h, followed by co-treatment with Baf for an additional 24 h, yielded a synergistic interaction. ELISA studies were performed to determine the effects of the autophagy modulators on MP trafficking. Treatment with Baf resulted in a concentration-dependent increase in intracellular MP level. Furthermore, addition of Baf potentiated the Lov-, DGBP-, or 3P-induced accumulation of intracellular MP. Neither 3-MA nor chloroquine increased intracellular MP levels by more than 20% and significant potentiation was not seen when these agents were combined with an IBPI. Finally, addition of the proteasome inhibitor bortezomib to the combination of Lov and Baf further increased intracellular MP levels. To evaluate the effects of combining IBPIs with autophagy inhibitors on autophagolysosome formation, studies were performed utilizing acridine orange staining and flow cytometric analysis. The shift from green to red fluorescence, a marker for acidic vesicular organelle (AVO) formation, was determined. These studies demonstrated that the select IBP inhibitors (DGBP and 3P to a greater extent than Lov) enhanced the Baf- and 3-MA-induced decrease in mean red:green fluorescence ratio. To determine whether Baf altered the ability of Lov to induce markers of the UPR, quantitative real time PCR studies were performed. These studies revealed that both Lov and Baf induce the upregulation of components of the UPR including PERK, IRE1, and GADD153. The combination of Lov and Baf further upregulated these UPR components compared with either agent alone. In conclusion, these studies demonstrate that the combination of the autophagy inhibitor Baf and select IBPIs results in enhancement of cytotoxic effects, disruption of MP trafficking, induction of components of the UPR, and inhibition of AVO formation. Further studies will be required to determine the extent to which autophagy regulates MP homeostasis, the mechanism underlying the differential effects of the autophagy inhibitors, and the effect of Rab inhibitors on autophagic processes in MM cells. This work forms the basis for future pre-clinical and clinical studies investigating the combination of inhibitors of MP secretion and autophagy in MM and related disorders. Disclosures: No relevant conflicts of interest to declare.
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Solomon, Alan, Deborah T. Weiss, Charles L. Murphy, Rudi Hrncic, Jonathan S. Wall та Maria Schell. "Light chain-associated amyloid deposits comprised of a novel κ constant domain". Proceedings of the National Academy of Sciences 95, № 16 (1998): 9547–51. http://dx.doi.org/10.1073/pnas.95.16.9547.
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Light chain-associated amyloidosis is characterized by the deposition as fibrils of monoclonal light chain-related components consisting predominately of the variable domain (VL) or the VL plus up to ≈60 residues of the constant domain (CL). Here, we describe a patient (designated BIF) with light chain-associated amyloidosis and κ Bence Jones proteinuria in whom, notably, >80% of the amyloid deposits were comprised of CL-related material. The extracted amyloid protein consisted of 99 aa residues identical in sequence to the main portion of the Cκ region (positions 109–207) of the precursor Bence Jones protein. Remarkably, the CLs from both molecules contained a Ser→Asn substitution at position 177. This heretofore undescribed Cκ alteration did not result from somatic mutation but rather was germline encoded. When tested in our in vitro fibrillogenic kinetic assay, Bence Jones protein BIF was highly amyloidogenic. Notably, endopeptidase treatment of amyloid fibrils prepared from the native light chain revealed the VL to be markedly susceptible to enzymatic digestion, whereas the CL was protease-resistant. Our findings provide evidence that the fragmented light chains typically present in this disease result from proteolytic degradation and suggest that, in this case, conformational differences in VL/CL packing within the fibrils may account for the unusual composition of the amyloid deposits. Additionally, we posit that the previously unrecognized Asn177 substitution represents yet another Cκ allotype, provisionally designated Km4.
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Dong, Meiqiu, Kai Miao, Yi Hu, et al. "Cooperating dipole–dipole and van der Waals interactions driven 2D self-assembly of fluorenone derivatives: ester chain length effect." Physical Chemistry Chemical Physics 19, no. 46 (2017): 31113–20. http://dx.doi.org/10.1039/c7cp06462d.
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Two-dimensional supramolecular assemblies of a series of 2,7-bis(10-n-alkoxycarbonyl-decyloxy)-9-fluorenone derivatives (BAF-Cn, n = 1, 3–6) consisting of polar fluorenone moieties and ester alkoxy chains were investigated by scanning tunneling microscopy on highly oriented pyrolytic graphite surfaces.
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Zhao, Xuejin, Yuanxin Wang, Shiwei Wang, Zhi Chen, Ying Wen, and Yuan Song. "Construction of a doramectin producer mutant from an avermectin-overproducing industrial strain of Streptomyces avermitilis." Canadian Journal of Microbiology 55, no. 12 (2009): 1355–63. http://dx.doi.org/10.1139/w09-098.
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The avermectin analogue doramectin (CHC-B1), which is produced in mutants that have an altered biosynthesis pathway of avermectin, is one of the most effective agricultural pesticides and antiparasitics. We report here the construction of a bkdF olmA double-deletion mutant lacking one of the branched-chain α-keto acid dehydrogenase encoding genes (bkdF) and the oligomycin PKS encoding gene cluster (olmA) in Streptomyces avermitilis 76-05. We then characterized the production of various antibiotics in cultures of the deletion mutant. In a fermentation medium supplemented with cyclohexanecarboxylic acid, this double mutant produced doramectin and its analogues but no oligomycin. The mutant proved to be genetically stable, without any antibiotic resistance markers inserted into its chromosome, and could potentially become an industrial doramectin-producing strain after further improvement.
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He, Qiang, Yinying Zhu, Leilei Fan, Hainan Ai, Xiaoliu Huangfu, and Mei Chen. "Effects of C/N ratio on nitrous oxide production from nitrification in a laboratory-scale biological aerated filter reactor." Water Science and Technology 75, no. 6 (2016): 1270–80. http://dx.doi.org/10.2166/wst.2016.447.
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Emission of nitrous oxide (N2O) during biological wastewater treatment is of growing concern. This paper reports findings of the effects of carbon/nitrogen (C/N) ratio on N2O production rates in a laboratory-scale biological aerated filter (BAF) reactor, focusing on the biofilm during nitrification. Polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) and microelectrode technology were utilized to evaluate the mechanisms associated with N2O production during wastewater treatment using BAF. Results indicated that the ability of N2O emission in biofilm at C/N ratio of 2 was much stronger than at C/N ratios of 5 and 8. PCR-DGGE analysis showed that the microbial community structures differed completely after the acclimatization at tested C/N ratios (i.e., 2, 5, and 8). Measurements of critical parameters including dissolved oxygen, oxidation reduction potential, NH4+-N, NO3−-N, and NO2−-N also demonstrated that the internal micro-environment of the biofilm benefit N2O production. DNA analysis showed that Proteobacteria comprised the majority of the bacteria, which might mainly result in N2O emission. Based on these results, C/N ratio is one of the parameters that play an important role in the N2O emission from the BAF reactors during nitrification.
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Ward, Donald E., Coen C. van der Weijden, Marthinus J. van der Merwe, Hans V. Westerhoff, Al Claiborne та Jacky L. Snoep. "Branched-Chain α-Keto Acid Catabolism via the Gene Products of the bkd Operon in Enterococcus faecalis: a New, Secreted Metabolite Serving as a Temporary Redox Sink". Journal of Bacteriology 182, № 11 (2000): 3239–46. http://dx.doi.org/10.1128/jb.182.11.3239-3246.2000.
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ABSTRACT Recently the bkd gene cluster from Enterococcus faecalis was sequenced, and it was shown that the gene products constitute a pathway for the catabolism of branched-chain α-keto acids. We have now investigated the regulation and physiological role of this pathway. Primer extension analysis identified the presence of a single promoter upstream of the bkd gene cluster. Furthermore, a putative catabolite-responsive element was identified in the promoter region, indicative of catabolite repression. Consistent with this was the observation that expression of the bkdgene cluster is repressed in the presence of glucose, fructose, and lactose. It is proposed that the conversion of the branched-chain α-keto acids to the corresponding free acids results in the formation of ATP via substrate level phosphorylation. The utilization of the α-keto acids resulted in a marked increase of biomass, equivalent to a net production of 0.5 mol of ATP per mol of α-keto acid metabolized. The pathway was active under aerobic as well as anaerobic conditions. However, under anaerobic conditions the presence of a suitable electron acceptor to regenerate NAD+ from the NADH produced by the branched-chain α-keto acid dehydrogenase complex was required for complete conversion of α-ketoisocaproate. Interestingly, during the conversion of the branched-chain α-keto acids an intermediate was always detected extracellularly. With α-ketoisocaproic acid as the substrate this intermediate was tentatively identified as 1,1-dihydroxy-4-methyl-2-pentanone. This reduced form of α-ketoisocaproic acid was found to serve as a temporary redox sink.
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Debarbouille, Michel, Rozenn Gardan, Maryvonne Arnaud, and George Rapoport. "Role of BkdR, a Transcriptional Activator of the SigL-Dependent Isoleucine and Valine Degradation Pathway inBacillus subtilis." Journal of Bacteriology 181, no. 7 (1999): 2059–66. http://dx.doi.org/10.1128/jb.181.7.2059-2066.1999.
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ABSTRACT A new gene, bkdR (formerly called yqiR), encoding a regulator with a central (catalytic) domain was found inBacillus subtilis. This gene controls the utilization of isoleucine and valine as sole nitrogen sources. Seven genes, previously called yqiS, yqiT, yqiU,yqiV, bfmBAA, bfmBAB, andbfmBB and now referred to as ptb,bcd, buk, lpd, bkdA1,bkdA2, and bkdB, are located downstream from the bkdR gene in B. subtilis. The products of these genes are similar to phosphate butyryl coenzyme A transferase, leucine dehydrogenase, butyrate kinase, and four components of the branched-chain keto acid dehydrogenase complex: E3 (dihydrolipoamide dehydrogenase), E1α (dehydrogenase), E1β (decarboxylase), and E2 (dihydrolipoamide acyltransferase). Isoleucine and valine utilization was abolished in bcd and bkdR null mutants ofB. subtilis. The seven genes appear to be organized as an operon, bkd, transcribed from a −12, −24 promoter. The expression of the bkd operon was induced by the presence of isoleucine or valine in the growth medium and depended upon the presence of the sigma factor SigL, a member of the sigma 54 family. Transcription of this operon was abolished in strains containing a null mutation in the regulatory gene bkdR. Deletion analysis showed that upstream activating sequences are involved in the expression of the bkd operon and are probably the target ofbkdR. Transcription of the bkd operon is also negatively controlled by CodY, a global regulator of gene expression in response to nutritional conditions.
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Wu, Kunrong, Xiaoli Li, Yuedong Xu, et al. "SLC22A1 rs622342 Polymorphism Predicts Insulin Resistance Improvement in Patients with Type 2 Diabetes Mellitus Treated with Metformin: A Cross-Sectional Study." International Journal of Endocrinology 2020 (May 8, 2020): 1–7. http://dx.doi.org/10.1155/2020/2975898.
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Background. Metformin is the most widely used oral antidiabetic agent and can reduce insulin resistance (IR) effectively. Organic cation transporter 1 (encoded by SLC22A1) is responsible for the transport of metformin, and ataxia-telangiectasia-mutated (ATM) is a gene relating to the DNA repair and cell cycle control. The aim of this study was to evaluate if the genetic variants in SLC22A1 rs622342 and ATM rs11212617 could be effective predictors of islet function improvement in patients with type 2 diabetes mellitus (T2DM) on metformin treatment. Methods. This cross-sectional study included 111 patients with T2DM treated with metformin. Genotyping was performed by the dideoxy chain-termination method. The homeostatic indexes of IR (HOMA-IR) and beta-cell function (HOMA-BCF) were determined according to the homeostasis model assessment. Results. Fasting plasma glucose (FPG) levels, HbA1c levels, and HOMA-IR were significantly higher in patients with the rs622342 AA genotype than in those with C allele (P<0.05). However, these significant differences were not observed between rs11212617 genotype groups. Further data analysis revealed that the association between the rs622342 polymorphism and HOMA-IR was gender related, and so was rs11212617 polymorphism and HOMA-BCF. HOMA-IR was significantly higher in males with rs622342 AA genotype than in those with C allele (P=0.021), and HOMA-BCF value was significantly higher in females carrying rs11212617 CC genotype than in those with A allele (P=0.038). The common logarithm (Lg10) of HOMA-BCF was positively correlated with the reciprocal of HbA1c (r = 0.629, P<0.001) and negatively associated with Lg10 FPG (r = −0.708, P<0.001). Conclusions. The variant of rs622342 could be a predictor of insulin sensitivity in patients with T2DM treated with metformin. The association between the rs622342 polymorphism and HOMA-IR and the association between the rs11212617 polymorphism and HOMA-BCF were both gender related.
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Pattharasiriwong, Patcharat, and Sarawut Rimdusit. "Characterizations of Fluorine-Containing Polybenzoxazine Prepared by Solventless Procedure." Key Engineering Materials 659 (August 2015): 368–72. http://dx.doi.org/10.4028/www.scientific.net/kem.659.368.
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A fluorine-containing benzoxazine monomer (BAF-4fa) from 4-(trifluoromethyl) aniline, 4,4′-(Hexafluoroisopropylidene) diphenol or bisphenol-AF and paraformaldehyde was synthesized using solventless method at temperature of 110°C without any catalyst. Chemical structure and thermal properties of as-synthesized benzoxazine resin were investigated and compared with fluorine-containing benzoxazine resin as well as with traditional bisphenol-A aniline based benzoxazine (BA-a) system. From Fourier transform infrared spectrum of BAF-4fa monomer, absorption band at 1243 cm-1 which were assigned to C-O-C stretching mode of oxazine ring and band around 1505 cm-1 and 951 cm-1 which were attributed to tri-substitutued benzene ring from the oxazine ring moieties were observed. The result is in good agreement with the BA-a monomer, indicating successful preparation of BAF-4fa via solventless technology. The obtained BAF-4fa also exhibits thermal curing ability which is a signature of benzoxazine resin. The exothermic heat of reaction of BAF-4fa was found to be less than that of BA-a as observed by a differential scanning calorimeter. The BAF-4fa monomer was step-cured at 200°C for 2 hours, 250°C for 3 hours followed by 270°C for 2 hours to achieve its fully cured stage. Glass transition temperature of PBAF-4fa from tanδ of dynamic mechanical analysis was found to be much higher than that of PBA-a i.e. 288°C vs 189°C. From thermogravimetric analysis, thermal degradation at 10% weight loss of PBAF-4fa was found to be 453°C compared to the value of 341°C of PBA-a while the char yield was 53% vs 28% of the BA-a polymer. As a consequence, the incorporation of fluorine atoms into polybenzoxazine is able to improve various thermal stability of the polymer which allows such application as high temperature resistance materials including electronic packaging, thermal resistance coating.
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Anugraha, Rendra Panca, Annasit Annasit, Ali Altway, Juwari Juwari, and Renanto Handogo. "The Optimization of Natural Gas Utilization Network in Single Region Using Pinch Analysis Method." ASEAN Journal of Chemical Engineering 20, no. 1 (2020): 57. http://dx.doi.org/10.22146/ajche.51953.
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Natural gas is one of the cleanest energy resources and may have potency to replace crude oil as main energy resource in several decades. There are some aspects which must be concern in the development of the natural gas industry including processing, storing, distributing and utilizing of the natural gas. The network of natural gas supply also should be generated to obtain the maximum natural gas recovery. However, it is difficult to determine the most suitable network system to connect the supply and demand of natural gas due to their different time scale, flowrate and capacity. There are some studies which investigating the network system to connect the supply and demand of natural gas but there are no systematical method in determination of the optimum natural gas network in single region supply-chain using pinch analysis. Therefore, in this study, a systematical method was developed to design natural gas network system in single region (East Java) using pinch analysis. The concept of natural gas cascade calculation was introduced. The heuristics of natural gas pairing between source and sink streams in grid diagram analysis was developed. Using 0-year time minimum difference give the amount of unutilized supply with value of 258.4 billion standard cubic feet (BCF) while 3-year time minimum difference give the amount of alternative and unutilized supply with value of 639.3 BCF and 897.7 BCF, respectively. The grid diagram heuristics developed in this study gives same results with the cascade calculation result.
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Maves, Ryan, Derek Larson, Michael Dempsey, et al. "Feasibility and Validation of Viral Respiratory Disease Surveillance in a Combat Theater Using the Filmarray Respiratory Panel." Open Forum Infectious Diseases 4, suppl_1 (2017): S360. http://dx.doi.org/10.1093/ofid/ofx163.874.
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Abstract Background Viral respiratory infections are a significant threat to deployed military units. Pathogen-based surveillance may be hampered by limitations in trained personnel in theater, difficulty with specimen shipment, and technical issues with equipment maintenance. In this project, we evaluated the performance of the FilmArray respiratory panel at military clinics in Afghanistan and compare results to testing performed in the United States. Methods Participants were recruited after presenting at military clinics at Bagram Airfield (BAF), Afghanistan, in 2013–2014 with fever (≥38° C) and respiratory symptoms (cough, dyspnea, chest pain, and/or sore throat). General medical laboratory staff at BAF were trained to operate the FilmArray; nasopharyngeal swabs were obtained and tested in-theater using the FilmArray respiratory panel (Biofire Diagnostics, Salt Lake City, UT). Samples were then shipped to the USAFSAM Applied Technology Center in 50% RNALater (Qiagen, Valencia, CA) without dry ice and then retested using the same panel. Selected influenza isolates then underwent sequencing to evaluate for potential novel circulating strains. Results 29 specimens underwent testing. A virus was identified on FilmArray in 22/29 specimens at BAF and 24/29 specimens at USAFSAM, of whom 17/29 had influenza A. Positive results between BAF and USAFSAM were concordant in all cases; 2 of the negative results at BAF were identified as having influenza A and rhinovirus, respectively. Among those with influenza A, all but one had undergone seasonal influenza vaccination. 5 influenza isolates then underwent sequencing; 2 were A(H1N1pdm09) consistent with the predominant 2012–2013 strain, while 3 were A(H3N2) viruses with HA mutations that differed from those in the 2013–2014 vaccine strain. No resistance-associated neuraminidase mutations were identified. Conclusion Surveillance using the FilmArray system is effective and feasible in theater by general laboratory staff. H1N1 and H3N2 influenza A viruses predominated in this sample of acute respiratory infections in a deployed military setting despite high vaccination rates. The use of the RNALater preservative is an effective method for specimen transport without requiring a cold chain and may facilitate biosurveillance in remote settings. Disclosures All authors: No reported disclosures.
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Hester, Kathryn L., Jodi Lehman, Fares Najar, et al. "Crc Is Involved in Catabolite Repression Control of the bkd Operons of Pseudomonas putida andPseudomonas aeruginosa." Journal of Bacteriology 182, no. 4 (2000): 1144–49. http://dx.doi.org/10.1128/jb.182.4.1144-1149.2000.
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ABSTRACT Crc (catabolite repression control) protein of Pseudomonas aeruginosa has shown to be involved in carbon regulation of several pathways. In this study, the role of Crc in catabolite repression control has been studied in Pseudomonas putida. The bkd operons of P. putida and P. aeruginosa encode the inducible multienzyme complex branched-chain keto acid dehydrogenase, which is regulated in both species by catabolite repression. We report here that this effect is mediated in both species by Crc. A 13-kb cloned DNA fragment containing the P. putida crc gene region was sequenced. Crc regulates the expression of branched-chain keto acid dehydrogenase, glucose-6-phosphate dehydrogenase, and amidase in both species but not urocanase, although the carbon sources responsible for catabolite repression in the two species differ. Transposon mutants affected in their expression of BkdR, the transcriptional activator of thebkd operon, were isolated and identified as crcand vacB (rnr) mutants. These mutants suggested that catabolite repression in pseudomonads might, in part, involve control of BkdR levels.
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Grøndahl, Frøy, Heidi Tveit, and Kristian Prydz. "Neutralization of endomembrane compartments in epithelial MDCK cells affects proteoglycan synthesis in the apical secretory pathway." Biochemical Journal 418, no. 3 (2009): 517–28. http://dx.doi.org/10.1042/bj20081179.
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PGs (proteoglycans) are proteins acquiring long, linear and sulfated GAG (glycosaminoglycan) chains during Golgi passage. In MDCK cells (Madin–Darby canine kidney cells), most of the CS (chondroitin sulfate) PGs are secreted apically, whereas most of the HS (heparan sulfate) PGs are secreted basolaterally. The apical and basolateral secretory routes differ in their GAG synthesis, since a protein core that traverses both routes acquires shorter chains, but more sulfate, in the basolateral pathway than in the apical counterpart [Tveit, Dick, Skibeli and Prydz (2005) J. Biol. Chem. 280, 29596–29603]. Golgi cisternae and the trans-Golgi network have slightly acidic lumens. We therefore investigated how neutralization of endomembrane compartments with the vacuolar H+-ATPase inhibitor Baf A1 (bafilomycin A1) affected GAG synthesis and PG sorting in MDCK cells. Baf A1 induced a slight reduction in basolateral secretion of macromolecules, which was compensated by an apical increase. More dramatic changes occurred to PG synthesis in the apical pathway on neutralization. The difference in apical and basolateral PG sulfation levels observed for control cells was abolished, due to enhanced sulfation of apical CS-GAGs. In addition, a large fraction of apical HS-GAGs was elongated to longer chain lengths. The differential sensitivity of the apical and basolateral secretory pathways to Baf A1 indicates that the apical pathway is more acidic than the basolateral counterpart in untreated MDCK cells. Neutralization gave an apical GAG output that was more similar to that of the basolateral pathway, suggesting that neutralization made the luminal environments of the two pathways more similar.
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Pająk, Marek, Michał Gąsiorek, Michał Jasik, Wiktor Halecki, Krzysztof Otremba, and Marcin Pietrzykowski. "Risk Assessment of Potential Food Chain Threats from Edible Wild Mushrooms Collected in Forest Ecosystems with Heavy Metal Pollution in Upper Silesia, Poland." Forests 11, no. 12 (2020): 1240. http://dx.doi.org/10.3390/f11121240.
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In this study, the contents of selected heavy metals (Zn, Cu, Cd, Pb, Cr, and Ni) and macroelements (C, N, K, P, S, Mg, Na, and Ca) were measured in wild mushrooms growing in a heavily polluted forest ecosystem in the northeastern part of the Upper Silesian Industrial Region. The research was conducted on 10 species of mushrooms belonging to three families: Boletaceae, Russulaceae, and Suillaceae. Using a spatial autoregressive model, the study showed a strong relationship between heavy metal concentrations (especially Zn, Pb, and Cd) and the distance from a source of industrial pollution (a zinc smelter, Huta Miasteczko Śląskie). The concentrations of potentially toxic metals (Pb and Cd) in mushrooms significantly exceeded food-acceptable standards. The bioconcentration factor (BCF), calculated as the ratio between the concentration in mushroom tissues and in forest soils overall, reached the highest values for cadmium (Cd). The highest accumulation capacity for Cd was noted for Imleria badia (BCF = 9.18), which was also the most abundant mushroom species in the study plots. In general, the established threshold values for Pb and Cd concentrations in consumer mushrooms and food products were exceeded up to almost 30-fold in the studied area. We conclude that the potential risk to human health of the toxic elements that enter the food chain through the harvesting and consumption of wild mushrooms from this region is significant.
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Xu, Zhen, Yong Liu, and Bang-Ce Ye. "PccD Regulates Branched-Chain Amino Acid Degradation and Exerts a Negative Effect on Erythromycin Production inSaccharopolyspora erythraea." Applied and Environmental Microbiology 84, no. 8 (2018): e00049-18. http://dx.doi.org/10.1128/aem.00049-18.
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ABSTRACTBranched-chain amino acid (BCAA) degradation is a major source of propionyl coenzyme A (propionyl-CoA), a key precursor of erythromycin biosynthesis inSaccharopolyspora erythraea. In this study, we found that thebkdoperon, responsible for BCAA degradation, was regulated directly by PccD, a transcriptional regulator of propionyl-CoA carboxylase genes. The transcriptional level of thebkdoperon was upregulated 5-fold in apccDgene deletion strain (ΔpccDstrain) and decreased 3-fold in apccDoverexpression strain (WT/pIB-pccD), demonstrating that PccD was a negative transcriptional regulator of the operon. The deletion ofpccDsignificantly improved the ΔpccDstrain's growth rate, whereaspccDoverexpression repressed WT/pIB-pccDgrowth rate, in basic Evans medium with 30 mM valine as the sole carbon and nitrogen source. The deletion ofgdhA1and the BcdhE1 gene (genes in thebkdoperon) resulted in lower growth rates of ΔgdhA1and ΔBcdhE1 strains, respectively, on 30 mM valine, further suggesting that thebkdoperon is involved in BCAA degradation. Bothbkdoverexpression (WT/pIB-bkd) andpccDinactivation (ΔpccDstrain) improve erythromycin production (38% and 64%, respectively), whereas the erythromycin production of strain WT/pIB-pccDwas decreased by 48%. Lastly, we explored the applications of engineeringpccDandbkdin an industrial high-erythromycin-producing strain.pccDdeletion in industrial strainS. erythraeaE3 (E3pccD) improved erythromycin production by 20%, and the overexpression ofbkdin E3ΔpccD(E3ΔpccD/pIB-bkd) increased erythromycin production by 39% compared withS. erythraeaE3 in an industrial fermentation medium. Addition of 30 mM valine to industrial fermentation medium further improved the erythromycin production by 23%, a 72% increase from the initial strainS. erythraeaE3.IMPORTANCEWe describe abkdoperon involved in BCAA degradation inS. erythraea. The genes of the operon are repressed by a TetR regulator, PccD. The results demonstrated that PccD controlled the supply of precursors for biosynthesis of erythromycin via regulating the BCAA degradation and propionyl-CoA assimilation and exerted a negative effect on erythromycin production. The findings reveal a regulatory mechanism in feeder pathways and provide new strategies for designing metabolic engineering to increase erythromycin yield.
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MATHBOR, GOLAM M. "Climate change on fisheries: Challenges and opportunities." Bangladesh Journal of Fisheries 32, no. 1 (2020): 151–62. http://dx.doi.org/10.52168/bjf.2020.32.17.
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Science has shown us that since Earth’s creation, climate has been affected by natural occurrences,both within and outside the climate system, but in recent years, climate is also being affected by actions andinactions of the human race. Climate system changes affect all life on earth, but fisheries are affected inparticular, because almost three-quarters of the Earth’s surface is water and home to a variety of aquatic life.Changing weather is producing more droughts, floods, rising sea levels, salt water intrusion of fresh water,acidity in the oceans and ocean warming. This paper discusses how climate change is affecting both marinelife in the oceans and aquatic species in fresh water, as well as the effects of these changes on the seafoodsupply chain and other revenue sources in coastal areas. Factors causing climate change and actions needed tomitigate these changes are also discussed.
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Cheng, Yicheng, Shenglin Mei, Xiangwei Kong, et al. "Long-term antibacterial activity of a composite coating on titanium for dental implant application." Journal of Biomaterials Applications 35, no. 6 (2020): 643–54. http://dx.doi.org/10.1177/0885328220963934.
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Dental implants are the most innovative and superior treatment modality for tooth replacement. However, titanium implants still suffer from insufficient antibacterial capability and peri-implant diseases remain one of the most common and intractable complications. To prevent peri-implant diseases, a composite coating containing a new antibacterial agent, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone (BBF) was fabricated on titanium. This study was designed to investigate the antibacterial activity of the composite coating against two common peri-implant pathogens ( Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans). The morphology of the composite coating showed that BBF-loaded poly(L-lactic acid) nanospheres were well-distributed in the pores of the microarc oxidation coating, and cross-linked with each other and the wall pores by gelatin. A release study indicated that the antibacterial coating could sustain the release of BBF for 60 d, with a slight initial burst release occurring during the first 4 h. The antibacterial rate of the composite coating for adhering bacteria was the highest (over 97%) after 1 d and over 90% throughout a 30-day incubation period. The total fluorescence intensity of the composite coating was the lowest, and the vast majority of the fluorescence was red (dead bacteria). Moreover, real-time polymerase chain reaction analysis confirmed that the relative gene expression of the adherent bacteria on the composite coating was down-regulated. It was therefore concluded that the composite coating fabricated on titanium, which showed excellent and relatively long-term antibacterial activity against Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, is a potential and promising strategy to be applied on dental implants for the prevention of peri-implant diseases.
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Madhusudhan, Kunapuli T., Jinhe Luo, and John R. Sokatch. "In Vitro Transcriptional Studies of thebkd Operon of Pseudomonas putida:l-Branched-Chain Amino Acids and d-Leucine Are the Inducers." Journal of Bacteriology 181, no. 9 (1999): 2889–94. http://dx.doi.org/10.1128/jb.181.9.2889-2894.1999.
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ABSTRACT BkdR is the transcriptional activator of the bkdoperon, which encodes the four proteins of the branched-chain keto acid dehydrogenase multienzyme complex of Pseudomonas putida. In this study, hydroxyl radical footprinting revealed that BkdR bound to only one face of DNA over the same region identified in DNase I protection assays. Deletions of even a few bases in the 5′ region of the BkdR-binding site greatly reduced transcription, confirming that the entire protected region is necessary for transcription. In vitro transcription of the bkd operon was obtained by using a vector containing the bkdR-bkdA1 intergenic region plus the putative ρ-independent terminator of the bkdoperon. Substrate DNA, BkdR, and any of thel-branched-chain amino acids or d-leucine was required for transcription. Branched-chain keto acids,d-valine, and d-isoleucine did not promote transcription. Therefore, the l-branched-chain amino acids and d-leucine are the inducers of the bkdoperon. The concentration of l-valine required for half-maximal transcription was 2.8 mM, which is similar to that needed to cause half-maximal proteolysis due to a conformational change in BkdR. A model for transcriptional activation of the bkdoperon by BkdR during enzyme induction which incorporates these results is presented.
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Zulqurnain Haider, Muhammad, Sabir Hussain, Pia Muhammad Adnan Ramzani, et al. "Bentonite and Biochar Mitigate Pb Toxicity in Pisum sativum by Reducing Plant Oxidative Stress and Pb Translocation." Plants 8, no. 12 (2019): 571. http://dx.doi.org/10.3390/plants8120571.
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Lead (Pb)-polluted soils pose a serious threat to human health, particularly by transmitting this heavy metal to the food chain via the crops grown on them. The application of novel amendments in Pb-polluted soils can significantly reduce this problem. In this research, we report the effects of various organic and inorganic amendments i.e., bentonite (BN), biochar (BR), lignin (LN), magnesium potassium phosphate cement (CM) and iron hydroxyl phosphate (FeHP), on the Pb bioavailability in Pb-polluted soil, upon Pb distribution in shoots, roots, grain, the translocation factor (TF) and the bioconcentration factor (BCF) of Pb in pea (Pisum sativum L.) grain. Furthermore, effects of the said amendments on the plant parameters, as well as grain biochemistry and nutritional quality, were also assessed. Lead pollution significantly elevated Pb concentrations in roots, shoots and grain, as well as the grain TF and BCF of Pb, while reducing the nutritional quality and biochemistry of grain, plant height, relative water content (RWC), chlorophyll contents (chl a and chl b) and the dry weight (DW) of shoot, root and grain. The lowest Pb distribution in shoots, roots and grain were found with BN, FeHP and CM, compared to our control. Likewise, the BN, FeHP and CM significantly lowered the TF and BCF values of Pb in the order FeHP > CM > BN. Similarly, the highest increase in plant height, shoot, root and grain DW, RWC, chl a and chl b contents, grain biochemistry and the micronutrient concentrations, were recorded with BR amendment. Biochar also reduced grain polyphenols as well as plant oxidative stress. Given that the BR and BN amendments gave the best results, we propose to explore their potential synergistic effect to reduce Pb toxicity by using them together in future research.
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PALING, Nicholas R. D., and Melanie J. WELHAM. "Role of the protein tyrosine phosphatase SHP-1 (Src homology phosphatase-1) in the regulation of interleukin-3-induced survival, proliferation and signalling." Biochemical Journal 368, no. 3 (2002): 885–94. http://dx.doi.org/10.1042/bj20021054.
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The tyrosine phosphatase SHP-1 (Src homology phosphatase-1) has been widely implicated as a negative regulator of signalling in immune cells. We have investigated in detail the role of SHP-1 in interleukin-3 (IL-3) signal transduction by inducibly expressing wild-type (WT), C453S (substrate-trapping) and R459M (catalytically inactive) forms of SHP-1 in the IL-3-dependent cell line BaF/3. Expression of WT SHP-1 had little impact on IL-3-induced proliferation, but enhanced apoptosis following IL-3 withdrawal. Expression of R459M SHP-1 increased the proliferative response of BaF/3 cells to IL-3 and increased cell survival at low doses of IL-3 and following IL-3 withdrawal. Investigation into the biochemical consequences resulting from expression of these SHP-1 variants demonstrated that the β chain of the IL-3 receptor (Aic2A) was hypo-phosphorylated in cells expressing WT SHP-1 and hyper-phosphorylated in those expressing R459M SHP-1. Further, ectopic expression of the trapping mutant, C453S SHP-1, protected Aic2A from dephosphorylation, suggesting that Aic2A is a SHP-1 substrate in BaF/3 cells. Examination of overall levels of tyrosine phosphorylation demonstrated that they were not perturbed in these transfectants. Activation-specific phosphorylation of STAT (signal transducer and activator of transcription) 5a/b, protein kinase B and ERK (extracellular-signal-regulated kinase)-1 and −2 was also unaffected by expression of WT or R459M SHP-1. However, overall levels of IL-3-induced tyrosine phosphorylation of STAT5 were reduced upon expression of WT SHP-1 and increased when R459M SHP-1 was expressed, consistent with STAT5 being a potential SHP-1 substrate. These results demonstrate that SHP-1 acts to negatively regulate IL-3-driven survival and proliferation, potentially via regulation of tyrosine phosphorylation of Aic2A and STAT5.
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Lindroos, M., P. Richards, J. Rikovska, et al. "Hyperfine interactions, including Bhf[FrFe], studied in the decay chain of225Ra by alpha and gamma anisotropy measurements." Hyperfine Interactions 75, no. 1-4 (1992): 323–30. http://dx.doi.org/10.1007/bf02398989.
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He, Enfang, Hong Zhang, Yueyue Gao, et al. "Side-chain effect on the photovoltaic performance of conjugated polymers based on benzodifuran and benzodithiophene-4,8-dione." MRS Advances 4, no. 36 (2019): 2001–7. http://dx.doi.org/10.1557/adv.2019.223.
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ABSTRACT:Two benzodifuran (BDF) polymers, PBDF-C and PBDF-S, with alkyl and alkylthio substituted thiophene side-chains and benzodithiophene-4,8-dione (BDD) as the acceptor were designed and synthesized. Their optical, electrochemical properties and photovoltaic performances were systematically investigated. The polymer solar cells (PSCs) with a device structure of ITO/PEDOT:PSS/polymer:PC71BM/Ca/Al were fabricated. The PBDF-C based device showed a power conversion efficiency (PCE) of 3.01% after adding 1 vol% 1,8-diodooctane (DIO) as the solvent additive, and PBDF-S gave an enhanced PCE of 3.48% without any post-treatments. The enhancements were from the higher open-circuit voltage (Voc) and fill factor (FF). The thermal- and solvent-treatment-free processing is more favourable for the large area roll-to-roll manufacturing or printing technology for PSCs.
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Liao, Mengchen, Yang Chen, and Michael A. Brook. "When Attempting Chain Extension, Even Without Solvent, It Is Not Possible to Avoid Chojnowski Metathesis Giving D3." Molecules 26, no. 1 (2021): 231. http://dx.doi.org/10.3390/molecules26010231.
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A simple, mild and efficient method to prepare HSi- or HOSi-telechelic, high-molecular-weight polydimethylsiloxane polymers (to 41,600 g·mol−1) using the one-shot hydrolysis of MHMH is reported; titration of the water allowed for higher molecular weights (to 153,900 g·mol−1). The “living” character of the chain extension processes was demonstrated by adding a small portion of MHMH and B(C6F5)3 (BCF) to a first formed polymer, which led to a ~2-fold, second growth in molecular weight. The heterogeneous reaction reached completion in less than 30 min, much less in some cases, regardless of whether it was performed neat or 50 wt% in dry toluene; homogeneous reactions in toluene were much slower. The process does not involve traditional redistribution, as judged by the low quantities (<3%) of D4 produced. However, it is not possible to avoid Chojnowski metathesis from MHDDMH giving D3, which occurs competitively with chain extension.
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Braungardt, Hannah, and Vineet K. Singh. "Impact of Deficiencies in Branched-Chain Fatty Acids and Staphyloxanthin inStaphylococcus aureus." BioMed Research International 2019 (January 22, 2019): 1–8. http://dx.doi.org/10.1155/2019/2603435.
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Staphylococcus aureusis a well-known human pathogen with the ability to cause mild superficial skin infections to serious deep-tissue infections, such as osteomyelitis, pneumonia, and infective endocarditis. A key toS. aureusinfections and its pathogenicity is its ability to survive in adverse environments, especially at lower temperatures, by regulation of its cell membrane. Branched-chain fatty acids (BCFAs) and staphyloxanthin have been shown to regulate membrane fluidity and staphylococcal virulence. This study was conducted with the hypothesis that the simultaneous lack of BCFAs and staphyloxanthin will have a far greater implication on environmental survival and virulence ofS. aureus. Lack of a functional branched-chainα-keto acid dehydrogenase (BKD) enzyme because of a mutation in thelpdAgene led to a decrease in the production of BCFAs, membrane fluidity, slower growth, and poorin vivosurvival ofS. aureus. A mutation in thecrtMgene eliminated the production of staphyloxanthin but it did not affect membrane BCFA levels, fluidity, growth, orin vivosurvival. AcrtM:lpdAdouble mutant showed much slower growth and attenuation compared to individual mutants. The results of this study suggest that simultaneous targeting of the BCFA and staphyloxanthin biosynthetic pathways can be a strategy to controlS. aureusinfections.
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Ward, Donald E., R. Paul Ross, Coen C. van der Weijden, Jacky L. Snoep та Al Claiborne. "Catabolism of Branched-Chain α-Keto Acids in Enterococcus faecalis: the bkd Gene Cluster, Enzymes, and Metabolic Route". Journal of Bacteriology 181, № 17 (1999): 5433–42. http://dx.doi.org/10.1128/jb.181.17.5433-5442.1999.
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ABSTRACT Genes encoding a branched-chain α-keto acid dehydrogenase fromEnterococcus faecalis 10C1, E1α (bkdA), E1β (bkdB), E2 (bkdC), and E3 (bkdD), were found to reside in the gene cluster ptb-buk-bkdDABC. The predicted products of ptb and buk exhibited significant homology to the phosphotransbutyrylase and butyrate kinase, respectively, from Clostridium acetobutylicum. Activity and redox properties of the purified recombinant enzyme encoded bybkdD indicate that E. faecalis has a lipoamide dehydrogenase that is distinct from the lipoamide dehydrogenase associated with the pyruvate dehydrogenase complex. Specific activity of the ptb gene product expressed in Escherichia coli was highest with the substrates valeryl-coenzyme A (CoA), isovaleryl-CoA, and isobutyryl-CoA. In cultures, a stoichiometric conversion of α-ketoisocaproate to isovalerate was observed, with a concomitant increase in biomass. We propose that α-ketoisocaproate is converted via the BKDH complex to isovaleryl-CoA and subsequently converted into isovalerate via the combined actions of theptb and buk gene products with the concomitant phosphorylation of ADP. In contrast, an E. faecalis bkdmutant constructed by disruption of the bkdA gene did not benefit from having α-ketoisocaproate in the growth medium, and conversion to isovalerate was less than 2% of the wild-type conversion. It is concluded that the bkd gene cluster encodes the enzymes that constitute a catabolic pathway for branched-chain α-keto acids that was previously unidentified inE. faecalis.
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Dykhuizen, Emily C., Leigh C. Carmody, Nicola Tolliday, Gerald R. Crabtree, and Michelle A. J. Palmer. "Screening for Inhibitors of an Essential Chromatin Remodeler in Mouse Embryonic Stem Cells by Monitoring Transcriptional Regulation." Journal of Biomolecular Screening 17, no. 9 (2012): 1221–30. http://dx.doi.org/10.1177/1087057112455060.
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The SWI/SNF-like adenosine triphosphate (ATP)–dependent chromatin remodeling complex, esBAF, is both necessary and, in some contexts, sufficient to induce the pluripotent state. Furthermore, mutations in various BAF subunits are associated with cancer. Little is known regarding the precise mechanism(s) by which this complex exerts its activities. Thus, it is unclear which protein interactions would be important to disrupt to isolate a relevant readout of mechanism. To address this, we developed a gene expression–based assay to identify inhibitors of the native esBAF complex. Specifically, a quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assay was developed in mouse embryonic stem (ES) cells to monitor expression of Bmi1, a developmentally important gene repressed by the esBAF complex. The assay was miniaturized to a 384-well format and used to screen a diverse collection of compounds, including novel products of diversity-oriented synthesis (DOS). Confirmed hits were validated using a knock-in ES cell reporter line in which luciferase is inserted into the Bmi1 locus. Several of the validated hits regulate a panel of target genes in a manner similar to the BAF chromatin-remodeling complex. Together these data indicate that expression-based screening using qRT-PCR is a successful approach to identify compounds targeting the regulation of key developmental genes in ES cells.
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Brinsmade, Shaun R., Roelco J. Kleijn, Uwe Sauer, and Abraham L. Sonenshein. "Regulation of CodY Activity through Modulation of Intracellular Branched-Chain Amino Acid Pools." Journal of Bacteriology 192, no. 24 (2010): 6357–68. http://dx.doi.org/10.1128/jb.00937-10.
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ABSTRACT In several Gram-positive bacterial species, the global transcriptional regulatory protein CodY adjusts the expression of many metabolic genes, apparently in response to changes in the pools of specific metabolites, i.e., the branched-chain amino acids (BCAAs) isoleucine, leucine, and valine (ILV) and the nucleoside triphosphate GTP. CodY not only responds to these metabolites as measured in vitro but also regulates the genes that direct their synthesis. We have constructed a set of strains lacking binding sites for the CodY protein in cis at loci coding for the ILV biosynthetic machinery, effectively overexpressing these genes in an attempt to modulate the ILV input signal to CodY. Metabolite analyses of strains derepressed for genes needed for ILV synthesis revealed more than a 6-fold increase in the valine pool and a 2-fold increase in the isoleucine and leucine pools. Accumulation of the branched-chain amino acids was accompanied by a 24-fold induction of the bkd operon (required for branched-chain fatty acid synthesis) and 6-fold hyperrepression of the CodY-regulated yhdG and yufN genes, demonstrating that CodY perceives intracellular fluctuations in at least one if its input signals. We conclude that changes in the rate of endogenous ILV synthesis serve as an important signal for CodY-mediated gene regulation.
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Puiu, Diana, Mariana Popescu, Marcela Niculescu, Luoana Florentina Pascu, Toma Galaon, and Carmen Postolache. "Mobility of Some High Persistent Organochlorine Compounds from Soil to Mentha Piperita." Revista de Chimie 70, no. 1 (2019): 278–82. http://dx.doi.org/10.37358/rc.19.1.6899.
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The fate of organochlorine compounds in soil ecosystem is shaped by their physical-chemical properties and by environmental conditions. The high persistence of polychlorobiphenyls (PCBs) in soil is given by a slow degradation which varies from months to years (the half-life of PCB 28 is 10.9 years, and PCB 52, 11.2 years). Due to high lipophilicity, these carcinogenic compounds can be easily uptaken by plants and transferred to the food chain. The widespread use of medicinal plant, Mentha Piperita, in pharmaceutical and food industry represents a risk of contamination and pollution. Through laboratory studies, we worked to identify the chemical behavior in soil and plants of some PCB congeners: 28, 52, 138, 153 and 180). The compounds mobility from soil to the roots and then through plant was monitored for 5 weeks. By optimizing the analytical method the contaminants were determined from soil and plant with good recoveries and with reduced limit of detection, below 0.01 mg/kg. It was reported that usually are uptaken into the plant high chlorinated PCBs like PCB 153 and PCB 180 but this study shows that after 5 weeks of PCB application, the concentration of PCB 28, a trichlorobiphenyl, is increasing. Fortunately, calculating the bioconcentration factor (BCF) of the selected PCBs in roots, it was shown that is similar to BCF of other plants like poplar and zucchini. The obtained value of 0.2 is assessed as being low.
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Zafrin, Mst Sadia, and Md Samsul Alam. "Microsatellite marker-based variation in the growth hormone genes of Nile tilapia (Oreochromis niloticus)." Bangladesh Journal of Fisheries 32, no. 1 (2020): 1–10. http://dx.doi.org/10.52168/bjf.2020.32.01.
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Polymorphisms in growth hormone genes have been found to cause variation in growth performance of fish. The objective of the study was to reveal variations in microsatellite loci located in the growth hormone genes of Nile tilapia (Oreochromis niloticus). Five microsatellite loci namely GH-MS01, IGFII, IGFII-MS01, IGFII-MS03, and STR were analyzed to assess the genetic variation in the growth hormone genes of four stocks of O. niloticus viz. FBG-Mini Hatchery, FM-Mini hatchery, Eon Aquaculture Ltd. and BFRI. The microsatellite markers were amplified by polymerase chain reaction, separated by polyacrylamide gel electrophoresis and visualized through ethidium bromide staining. All the five loci were found to be polymorphic. The average number of alleles of FM-Mini hatchery stock (3.8) was found to be highest and that of the FBG-Mini hatchery (2.8) and Eon Aquaculture stocks was found to be lowest. The average observed heterozygosity (Ho) value of the FM-Mini hatchery stock was the highest (0.140) and that of FBG-Mini hatchery stock was the lowest (0.040). On the other hand, the average expected heterozygosity (He) was highest in the BFRI stock (0.660) and lowest in the FM-Mini hatchery and FBG-Mini hatchery stock (0.432). The fixation index (1 - (Ho / He) values were positive in all the loci (except locus GH-MS01 in Eon Aquaculture stock), which means these stocks (O. niloticus) were deficient in heterozygosity. Deviation from Hardy-Weinberg expectation at STR locus in FBG-Mini hatchery and Eon Aquaculture stocks were not significant but in all other cases the deviations were found to be significant. The results provide evidence that genetic variation exists within the growth hormone genes in all four stocks of O. niloticus. The polymorphisms that have been detected in the present study can be used to study association with growth and thus selection of fast growing Nile tilapia in Bangladesh.
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Ram, Han, Yang, Ling, and Dong. "Effect of Hexavalent Chromium [Cr(VI)] on Phytoremediation Potential and Biochemical Response of Hybrid Napier Grass with and without EDTA Application." Plants 8, no. 11 (2019): 515. http://dx.doi.org/10.3390/plants8110515.
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Hexavalent chromium [Cr(VI)] contamination has become an emergent concern in China. Previous field investigations have found that hybrid Napier grass is widely distributed in Cr(VI) contaminated areas. This study investigated the phytoremediation potential and biochemical response of hybrid Napier grass (Pennisetum americanus L. × Pennisetum purpureum Schumach) grown in soil contaminated with Cr(VI) (0, 20, 40, and 60 mg kg−1) with and without Ethylene diamine tetra acetic acid (EDTA) (4 mM) application. The results indicated that root length, shoot height, dry weight, leaf area, chlorophyll, and photosystem II (PSII) parameters viz.; apparent electron transport rate (ETR), effective quantum yield of PSII (ΦPSⅡ), maximal PSII photochemical efficiency (Fv/Fm), potential activity of PSII (Fv/Fo), photochemical quenching (qP), and non-photochemical quenching (qN) decreased with the increasing Cr(VI) concentration. EDTA application further aggravated reduction of dry biomass and photosystem II. The concentration and the accumulation of Cr in shoot and root, and both the bioaccumulation factor (BAF) and transfer factor (TF) increased with increasing Cr(VI) concentrations and further enhanced with EDTA application. Though the Cr(VI) and Ethylene diamine tetra acetic acid (EDTA) stress reduced tolerance, but, even at highest Cr(VI) concentration, plant could exhibited strong resistance, as evidenced by increase in superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities. Hybrid Napier grass, due to its BAF > 1 and a TF < 1, would be applicable for Cr phytostabilization. Moreover, limiting metal transport to aerial parts of plant would prevent animal’s ingestion, restrict soil mobility, and consequently reduce transmission across the food chain.
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Weening, Eric H., Jared D. Barker, Marijke C. Laarakker, Andrea D. Humphries, Renée M. Tsolis, and Andreas J. Bäumler. "The Salmonella enterica Serotype Typhimurium lpf, bcf, stb, stc, std, and sth Fimbrial Operons Are Required for Intestinal Persistence in Mice." Infection and Immunity 73, no. 6 (2005): 3358–66. http://dx.doi.org/10.1128/iai.73.6.3358-3366.2005.
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ABSTRACT Salmonella enterica serotype Typhimurium causes human infections that can frequently be traced back through the food chain to healthy livestock whose intestine is colonized by the pathogen. Little is known about the genes important for intestinal carriage of S. enterica serotype Typhimurium in vertebrate animals. Here we characterized the role of 10 fimbrial operons, agf, fim, lpf, pef, bcf, stb, stc, std, stf, and sth, using competitive infection experiments performed in genetically susceptible (BALB/c) and resistant (CBA) mice. Deletion of agfAB, fimAICDHF, lpfABCDE, pefABCDI, bcfABCDEFG, stbABCD, stcABCD, stdAB, stfACDEFG, or sthABCDE did not reduce the ability of S. enterica serotype Typhimurium to colonize the spleen and cecum of BALB/c mice 5 days after infection. Similarly, deletion of agfAB, fimAICDHF, pefABCDI, and stfACDEFG did not result in reduced recovery of S. enterica serotype Typhimurium from fecal samples collected from infected CBA mice over a 30-day time period. However, S. enterica serotype Typhimurium strains carrying deletions in lpfABCDE, bcfABCDEFG, stbABCD, stcABCD, stdAB, or sthABCDE were recovered at significantly reduced numbers from the feces of CBA mice. There was a good correlation (R 2 = 0.9626) between competitive indices in the cecum and fecal samples of CBA mice at 30 days after infection, suggesting that the recovery of S. enterica serotype Typhimurium from fecal samples closely reflected its ability to colonize the cecum. Collectively, these data show that six fimbrial operons (lpf, bcf, stb, stc, std, and sth) contribute to long-term intestinal carriage of S. enterica serotype Typhimurium in genetically resistant mice.