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Esparza, M., B. Bowien, Eugenia Jedlicki, and David S. Holmes. "Gene Organization and CO2-Responsive Expression of Four cbb Operons in the Biomining Bacterium Acidithiobacillus Ferrooxidans." Advanced Materials Research 71-73 (May 2009): 207–10. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.207.
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Acidithiobacillus ferrooxidans is an obligately chemolithoautotrophic, -proteobacterium that fixes CO2 by the Calvin-Benson-Bassham (CBB) reductive pentose phosphate cycle. Our objective is to identify genes potentially involved in CO2 fixation and to advance our understanding of how they might be regulated in response to environmental signals. Bioinformatic analyses, based on the complete genome sequence of the type strain ATCC 23270, identified five cbb gene clusters four of which we show experimentally to be operons. These operons are predicted to encode: (i) the components of the carboxysome and one copy of form I RubisCO (cbb1 operon), (ii) a second copy of form I RubisCO (cbb2 operon), (iii) enzymes of central carbon metabolism (cbb3 operon), (iv) a phosphoribulokinase and enzymes of sulfur metabolism (cbb4 operon) and RubisCO form II (cbb5 gene cluster). In addition, the gene for a LysR-type transcriptional regulator CbbR was identified immediately upstream and in divergent orientation to the cbb1 operon and another associated with the cbb5 gene cluster. A. ferrooxidans was grown under different concentrations of CO2 (2.5 to 20% [v/v]), and levels of mRNA and protein were evaluated by qPCR and Western blotting, respectively. CbbR binding to predicted promoter regions of operons cbb1-4 was assayed by EMSA This information permitted the formulation of models explaining how these operons might be regulated by environmental CO2 concentrations. These models were evaluated in vivo in a heterologous host, using cloned A. ferrooxidans cbbR to complement a mutant of the facultative chemoautotroph Ralstonia eutropha H16 lacking a functional cbbR. Cloned copies of A. ferrooxidans promoter regions were also introduced into R. eutropha to evaluate their ability to drive reporter gene expression. This work lays the framework for further studies that should result in a more comprehensive picture of how CO2 fixation is regulated in A. ferrooxidans.
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Paoli, George C., Padungsri Vichivanives, and F. Robert Tabita. "Physiological Control and Regulation of the Rhodobacter capsulatus cbb Operons." Journal of Bacteriology 180, no. 16 (August 15, 1998): 4258–69. http://dx.doi.org/10.1128/jb.180.16.4258-4269.1998.
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ABSTRACT The genes encoding enzymes of the Calvin-Benson-Bassham (CBB) reductive pentose phosphate pathway in Rhodobacter capsulatus are organized in at least two operons, each preceded by a separate cbbR gene, encoding potential LysR-type transcriptional activators. As a prelude to studies ofcbb gene regulation in R. capsulatus, the nucleotide sequence of a 4,537-bp region, which includedcbbR II, was determined. This region contained the following open reading frames: a partial pgmgene (encoding phosphoglucomutase) and a complete qorgene (encoding NADPH:quinone oxidoreductase), followed by cbbR II, cbbF (encoding fructose 1,6-bisphosphatase), cbbP (encoding phosphoribulokinase), and part of cbbT (encoding transketolase). Physiological control of the CBB pathway and regulation of the R. capsulatus cbb genes were studied by using a combination of mutant strains and promoter fusion constructs. Characterization of mutant strains revealed that either form I or form II ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), encoded by the cbbLS andcbbM genes, respectively, could support photoheterotrophic and autotrophic growth. A strain with disruptions in both cbbL and cbbM could not grow autotrophically and grew photoheterotrophically only when dimethyl sulfoxide was added to the culture medium. Disruption ofcbbP resulted in a strain that did not synthesize form II RubisCO and had a phenotype similar to that observed in the RubisCO-minus strain, suggesting that there is only onecbbP gene in R. capsulatus and that this gene is cotranscribed with cbbM. Analysis of RubisCO activity and synthesis in strains with disruptions in eithercbbR I orcbbR II, and β-galactosidase determinations from wild-type and mutant strains containing cbb Ip- andcbb IIp-lacZ fusion constructs, indicated that the cbb I andcbb II operons of R. capsulatus are within separate CbbR regulons.
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Li, Xiangmin, Jiayu Tang, Jinjin Dai, and Ning Bo. "Dynamic Coalition Task Allocation of Heterogeneous Multiple Agents." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 5 (October 2020): 1094–104. http://dx.doi.org/10.1051/jnwpu/20203851094.
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The dynamic coalition task allocation of heterogeneous multiple UAV agents is researched, which is divided into two parts. Firstly, the consensus based coalition algorithm(CBCA) is presented via consensus based bundle algorithm(CBBA), considering complex constraints of specific equipment requirements and coupling the relationships between the subtasks and the time windows. Secondly, three dynamic planning strategies are proposed in cope with appearance of new tasks during the allocation process. Finally, the feasibility and applicability of the present algorithm and dynamic planning strategies are validated in the scenario of a search and attack mission executed by multiple unmanned search aerial vehicles(USAVs) and unmanned combat aerial vehicles (UCAVs).
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Joshi, Gauri S., Simona Romagnoli, Nathan C. VerBerkmoes, Robert L. Hettich, Dale Pelletier, and F. Robert Tabita. "Differential Accumulation of Form I RubisCO in Rhodopseudomonas palustris CGA010 under Photoheterotrophic Growth Conditions with Reduced Carbon Sources." Journal of Bacteriology 191, no. 13 (April 17, 2009): 4243–50. http://dx.doi.org/10.1128/jb.01795-08.
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ABSTRACT Rhodopseudomonas palustris is unique among characterized nonsulfur purple bacteria because of its capacity for anaerobic photoheterotrophic growth using aromatic acids. Like growth with other reduced electron donors, this growth typically requires the presence of bicarbonate/CO2 or some other added electron acceptor in the growth medium. Proteomic studies indicated that there was specific accumulation of form I ribulose 1, 5-bisphosphate carboxylase/oxygenase (RubisCO) subunit proteins (CbbL and CbbS), as well as the CbbX protein, in cells grown on benzoate without added bicarbonate; such cells used the small amounts of dissolved CO2 in the medium to support growth. These proteins were not observed in extracts from cells grown in the presence of high levels (10 mM) of added bicarbonate. To confirm the results of the proteomics studies, it was shown that the total RubisCO activity levels were significantly higher (five- to sevenfold higher) in wild-type (CGA010) cells grown on benzoate with a low level (0.5 mM) of added bicarbonate. Immunoblots indicated that the increase in RubisCO activity levels was due to a specific increase in the amount of form I RubisCO (CbbLS) and not in the amount of form II RubisCO (CbbM), which was constitutively expressed. Deletion of the main transcriptional regulator gene, cbbR, resulted in impaired growth on benzoate-containing low-bicarbonate media, and it was established that form I RubisCO synthesis was absolutely and specifically dependent on CbbR. To understand the regulatory role of the CbbRRS two-component system, strains with nonpolar deletions of the cbbRRS genes were grown on benzoate. Distinct from the results obtained with photoautotrophic growth conditions, the results of studies with various CbbRRS mutant strains indicated that this two-component system did not affect the observed enhanced synthesis of form I RubisCO under benzoate growth conditions. These studies indicate that diverse growth conditions differentially affect the ability of the CbbRRS two-component system to influence cbb transcription.
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Lee, Chang-Hun, Gun-Hee Moon, Dong-Wan Yoo, Min-Jea Tahk, and In-Seok Lee. "Distributed Task Assignment Algorithm for SEAD Mission of Heterogeneous UAVs Based on CBBA Algorithm." Journal of the Korean Society for Aeronautical & Space Sciences 40, no. 11 (November 1, 2012): 988–96. http://dx.doi.org/10.5139/jksas.2012.40.11.988.
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Wang, Qing Wei, Ting Feng Lu, Jia Guo, and Xiu Mei Li. "Synthesis and Crystal Structure of a Fe(II,III) Complex with 2-(4΄-Chlorine-benzoyl)-benzoic acid and 3-(2-Pyridyl)pyrazole." Advanced Materials Research 634-638 (January 2013): 2592–95. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.2592.
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A new metal-organic complex FeII2FeIII2(cbba)4(L)6 (Hcbba = 2-(4΄-chlorine-benzoyl) benzoic acid, L = 3-(2-pyridyl)pyrazole) 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses, TG and IR spectroscopy. The compound crystallizes in monoclinic, space group Cc with a = 17.729(5), b = 15.919(5), c = 33.650(5) Å, β = 92.058(5)°, V = 9491(4) Å3, C104H68Cl4Fe4N18O12, Mr = 2126.96, Dc = 1.489 g/cm3, μ(MoKα) = 0.786 mm1, F(000) = 4344, Z = 4, the final R = 0.0559 and wR = 0.1122 for 12093 observed reflections (I > 2(I)).
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Welling, Matthew T., Myrna A. Deseo, Antony Bacic, and Monika S. Doblin. "Untargeted Metabolomic Analyses Reveal Chemical Complexity of Dioecious Cannabis Flowers." Australian Journal of Chemistry 74, no. 6 (2021): 463. http://dx.doi.org/10.1071/ch21033.
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Cannabis is a mostly dioecious multi-use flowering plant genus. Sexual dimorphism is an important characteristic in Cannabis-based commercial production systems, which has consequences for fibre, seed, and the yield of secondary metabolites, such as phytocannabinoid and terpenes for therapeutic uses. Beyond the obvious morphological differences between male and female plants, metabolic variation among dioecious flowers is largely undefined. Here, we report a pilot metabolomic study comparing staminate (male) and pistillate (female) unisexual flowers. Enrichment of the α-linolenic acid pathway and consensus evaluation of the jasmonic acid (JA) related compound 12-oxo-phytodienoicacid (OPDA) among differentially abundant metabolites suggests that oxylipin signalling is associated with secondary metabolism and sex expression in female flowers. Several putative phytocannabinoid-like compounds were observed to be upregulated in female flowers, but full identification was not possible due to the limitation of available databases. Targeted analysis of 14 phytocannabinoids using certified reference standards (cannabidiolic acid (CBDA), cannabidiol (CBD), Δ9-tetrahydrocannabinolic acid A (Δ9-THCAA), Δ9-tetrahydrocannabinol (Δ9-THC), cannabichromenic acid (CBCA), cannabichromene (CBC), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabinolic acid (CBNA), cannabinol (CBN), cannabidivarinic acid (CBDVA), cannabidivarin (CBDV), tetrahydrocannabivarinic acid (THCVA), and tetrahydrocannabivarin (THCV)) showed a higher total phytocannabinoid content in female flowers compared with the male flowers, as expected. In summary, the development of a phytocannabinoid-specific accurate-mass MSn fragmentation spectral library and gene pool representative metabolome has the potential to improve small molecule compound annotation and accelerate understanding of metabolic variation underlying phenotypic diversity in Cannabis.
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Tourova, Tatjana P., Olga L. Kovaleva, Dimitry Yu Sorokin, and Gerard Muyzer. "Ribulose-1,5-bisphosphate carboxylase/oxygenase genes as a functional marker for chemolithoautotrophic halophilic sulfur-oxidizing bacteria in hypersaline habitats." Microbiology 156, no. 7 (July 1, 2010): 2016–25. http://dx.doi.org/10.1099/mic.0.034603-0.
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The presence and diversity of the cbb genes encoding the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) (a key enzyme of the Calvin–Benson cycle of autotrophic CO2 assimilation) were investigated in pure cultures of seven genera of halophilic chemolithoautotrophic sulfur-oxidizing bacteria (SOB) and in sediments from a hypersaline lake in which such bacteria have been recently discovered. All of the halophilic SOB strains (with the exception of Thiohalomonas nitratireducens) possessed the cbbL gene encoding RuBisCO form I, while the cbbM gene encoding RuBisCO form II was detected only in some of the pure cultures. The general topologies of the CbbL/CbbM trees and the 16S rRNA gene tree were different, but both markers showed that the halophilic SOB genera formed independent lineages in the Gammaproteobacteria. In some cases, such as with several strains of the genus Thiohalospira and with Thioalkalibacter halophilus, the cbbL clustering was incongruent with the positions of these strains on the ribosomal tree. In the cbbM tree, the clustering of Thiohalospira and Thiohalorhabdus strains was incongruent with their branching in both cbbL and 16S rRNA gene trees. cbbL and cbbM genes related to those found in the analysed halophilic SOB were also detected in a sediment from a hypersaline lake in Kulunda Steppe (Russia). Most of the cbbL and cbbM genes belonged to members of the genus Thiohalorhabdus. In the cbbL clone library, sequences related to those of Halothiobacillus and Thiohalospira were detected as minor components. Some of the environmental cbbM sequences belonged to as yet unknown phylotypes, representing deep lineages of halophilic autotrophs.
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Li, Xiu Mei, Zhi Tao Wang, and Qing Wei Wang. "Synthesis and Crystal Structure of a Cadmium(II) Complex with 2-(4΄-Chlorine-Benzoyl)-Benzoic Acid and 1,10-Phenanthroline." Advanced Materials Research 339 (September 2011): 313–16. http://dx.doi.org/10.4028/www.scientific.net/amr.339.313.
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A new metal-organic complex Cd2(cbba)4(phen)2 (Hcbba = 2-(4΄-chlorine-benzoyl)- benzoic acid, phen = 1,10-phenanthroline) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, fluorescence spectrum and single-crystal X-ray diffraction. The compound crystallizes in orthorhombic, space group Pbcn with a = 12.0976(4), b = 18.0925(6), c = 31.6829(10) Å, V = 6934.6(4) Å3, C80H48Cd2Cl4N4O12, Mr = 1623.82, Dc = 1.555 g/cm3, μ(MoKα) = 0.8365 mm1, F(000) = 3264, Z = 4, the final R = 0.0396 and wR = 0.0960 for 5372 observed reflections (I > 2(I)). It exhibits a 3D supramolecular network through π-π interactions and shows green luminescent property at room temperature.
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ZHOU, CHENGWEN, and RAMON F. DACHEUX. "Glycine- and GABA-activated inhibitory currents on axon terminals of rabbit cone bipolar cells." Visual Neuroscience 22, no. 6 (November 2005): 759–67. http://dx.doi.org/10.1017/s095252380522607x.
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Glycine- and GABA-activated currents were examined in the axon terminals of 12 types of rabbit cone bipolar cells. In the superfused retinal slice, a cell was voltage clamped at 0 mV in the presence of cobalt; then glycine or GABA was puffed onto the axon terminal. Types CBa1, CBa2, and a few CBa1-2 cells demonstrated larger glycine-activated currents than GABA-activated ones. However, some OFF cells (CBa2n, CBa1-2n, CBa1w), most CBa1-2, and most ON cells (CBb3, CBb3-4, CBb3n, and CBb4) displayed larger GABA-activated currents. The ON cell, CBb5, possessed only a GABA-activated current. The predominance of glycinergic currents in CBa1, CBa2, and a few CBa1-2 cells suggests a major input from the glycinergic AII amacrine cell and thus a key role for these cells in the rod bipolar pathway. Certain OFF cells (most CBa1-2) expressed larger GABA-activated currents. All types expressed both GABAA and GABAC currents about equally, although most OFF types (CBa1, CB a2n, CBa1-2, and CBa2n) displayed a slightly greater GABAA component.
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Sun, Xiaolei, Naiming Qi, and Weiran Yao. "Boolean Networks-Based Auction Algorithm for Task Assignment of Multiple UAVs." Mathematical Problems in Engineering 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/425356.
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This paper presents an application of Boolean networks-based auction algorithm (BNAA) for task assignment in unmanned aerial vehicles (UAVs) systems. Under reasonable assumptions, the assignment framework consists of mission control system, communication network, and ground control station. As the improved algorithm of consensus-based bundle algorithm (CBBA), the BNAA utilizes a cluster-based combinatorial auction policy to handle multiple tasks. Instead of empirical method based on look-up table about conditional variables, Boolean network is introduced into consensus routine of BNAA for solving the conflict of assignment across the fleet of UAVs. As a new mathematic theory, semitensor product provides the implementation and theoretical proof of Boolean networks. Numerical results demonstrate the effectiveness and efficiency of proposed BNAA method.
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Fu, Xiaowei, Peng Feng, Bin Li, and Xiaoguang Gao. "A Two-Layer Task Assignment Algorithm for UAV Swarm Based on Feature Weight Clustering." International Journal of Aerospace Engineering 2019 (November 26, 2019): 1–12. http://dx.doi.org/10.1155/2019/3504248.
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For the large-scale operations of unmanned aerial vehicle (UAV) swarm and the large number of UAVs, this paper proposes a two-layer task and resource assignment algorithm based on feature weight clustering. According to the numbers and types of task resources of each UAV and the distances between different UAVs, the UAV swarm is divided into multiple UAV clusters, and the large-scale allocation problem is transformed into several related small-scale problems. A two-layer task assignment algorithm based on the consensus-based bundle algorithm (CBBA) is proposed, and this algorithm uses different consensus rules between clusters and within clusters, which ensures that the UAV swarm gets a conflict-free task assignment solution in real time. The simulation results show that the algorithm can assign tasks effectively and efficiently when the number of UAVs and targets is large.
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Zhang, Yaozhong, Wencheng Feng, Guoqing Shi, Frank Jiang, Morshed Chowdhury, and Sai Ho Ling. "UAV Swarm Mission Planning in Dynamic Environment Using Consensus-Based Bundle Algorithm." Sensors 20, no. 8 (April 17, 2020): 2307. http://dx.doi.org/10.3390/s20082307.
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To solve the real-time complex mission-planning problem for Multiple heterogeneous Unmanned Aerial Vehicles (UAVs) in the dynamic environments, this paper addresses a new approach by effectively adapting the Consensus-Based Bundle Algorithms (CBBA) under the constraints of task timing, limited UAV resources, diverse types of tasks, dynamic addition of tasks, and real-time requirements. We introduce the dynamic task generation mechanism, which satisfied the task timing constraints. The tasks that require the cooperation of multiple UAVs are simplified into multiple sub-tasks to perform by a single UAV independently. We also introduce the asynchronous task allocation mechanism. This mechanism reduces the computational complexity of the algorithm and the communication time between UAVs. The partial task redistribution mechanism has been adopted for achieving the dynamic task allocation. The real-time performance of the algorithm is assured on the premise of optimal results. The feasibility and real-time performance of the algorithm are validated by conducting dynamic simulation experiments.
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Kopeikin, Andrew N., Sameera S. Ponda, Luke B. Johnson, and Jonathan P. How. "Dynamic Mission Planning for Communication Control in Multiple Unmanned Aircraft Teams." Unmanned Systems 01, no. 01 (June 20, 2013): 41–58. http://dx.doi.org/10.1142/s2301385013500039.
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A multi-UAV system relies on communications to operate. Failure to communicate remotely sensed mission data to the base may render the system ineffective, and the inability to exchange command and control messages can lead to system failures. This paper describes a unique method to control network communications through distributed task allocation to engage under-utilized UAVs to serve as communication relays and to ensure that the network supports mission tasks. This work builds upon a distributed algorithm previously developed by the authors, CBBA with Relays, which uses task assignment information, including task location and proposed execution time, to predict the network topology and plan support using relays. By explicitly coupling task assignment and relay creation processes, the team is able to optimize the use of agents to address the needs of dynamic complex missions. In this work, the algorithm is extended to explicitly consider realistic network communication dynamics, including path loss, stochastic fading, and information routing. Simulation and flight test results validate the proposed approach, demonstrating that the algorithm ensures both data-rate and interconnectivity bit-error-rate requirements during task execution.
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Romagnoli, Simona, and F. Robert Tabita. "A Novel Three-Protein Two-Component System Provides a Regulatory Twist on an Established Circuit To Modulate Expression of the cbbI Region of Rhodopseudomonas palustris CGA010." Journal of Bacteriology 188, no. 8 (April 15, 2006): 2780–91. http://dx.doi.org/10.1128/jb.188.8.2780-2791.2006.
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ABSTRACT A novel two-component system has been identified in the cbbI region of the nonsulfur purple photosynthetic bacterium Rhodopseudomonas palustris. Genes encoding this system, here designated cbbRRS, are juxtaposed between the divergently transcribed transcription activator gene, cbbR, and the form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) genes, cbbLS. The three genes of the cbbRRS system represent a variation of the well-known two-component signal transduction systems, as there are a transmembrane hybrid sensor kinase and two response regulators, with no apparent DNA binding domain associated with any of the three proteins encoded by these genes. In this study, we showed that the membrane-bound full-length kinase undergoes autophosphorylation and transfers phosphate to both response regulators. A soluble, truncated version of the kinase was subsequently prepared and found to catalyze phosphorylation of response regulator 1 but not response regulator 2, implying that conformational changes and/or sequence-specific regions of the kinase are important for discriminating between the two response regulators. Analyses indicated that a complex network of control of gene expression must occur, with CbbR required for the expression of the cbbLS genes but dispensable for the synthesis of form II RubisCO (encoded by cbbM). The CbbRRS proteins specifically affected the activity and accumulation of form I RubisCO (CbbLS), as revealed by analyses of nonpolar, unmarked gene deletions. A tentative model of regulation suggested that changes in the phosphotransfer activity of the sensor kinase, possibly in response to a redox metabolic signal, cause modulation of the activity and synthesis of form I RubisCO.
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Tsai, Yi-Chin Candace, Fuzhou Ye, Lynette Liew, Di Liu, Shashi Bhushan, Yong-Gui Gao, and Oliver Mueller-Cajar. "Insights into the mechanism and regulation of the CbbQO-type Rubisco activase, a MoxR AAA+ ATPase." Proceedings of the National Academy of Sciences 117, no. 1 (December 17, 2019): 381–87. http://dx.doi.org/10.1073/pnas.1911123117.
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The vast majority of biological carbon dioxide fixation relies on the function of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). In most cases the enzyme exhibits a tendency to become inhibited by its substrate RuBP and other sugar phosphates. The inhibition is counteracted by diverse molecular chaperones known as Rubisco activases (Rcas). In some chemoautotrophic bacteria, the CbbQO-type Rca Q2O2 repairs inhibited active sites of hexameric form II Rubisco. The 2.2-Å crystal structure of the MoxR AAA+ protein CbbQ2 fromAcidithiobacillus ferrooxidansreveals the helix 2 insert (H2I) that is critical for Rca function and forms the axial pore of the CbbQ hexamer. Negative-stain electron microscopy shows that the essential CbbO adaptor protein binds to the conserved, concave side of the CbbQ2 hexamer. Site-directed mutagenesis supports a model in which adenosine 5′-triphosphate (ATP)-powered movements of the H2I are transmitted to CbbO via the concave residue L85. The basal ATPase activity of Q2O2 Rca is repressed but strongly stimulated by inhibited Rubisco. The characterization of multiple variants where this repression is released indicates that binding of inhibited Rubisco to the C-terminal CbbO VWA domain initiates a signal toward the CbbQ active site that is propagated via elements that include the CbbQ α4-β4 loop, pore loop 1, and the presensor 1-β hairpin (PS1-βH). Detailed mechanistic insights into the enzyme repair chaperones of the highly diverse CO2fixation machinery of Proteobacteria will facilitate their successful implementation in synthetic biology ventures.
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Garfinkel, Andrea R., Matthew Otten, and Seth Crawford. "SNP in Potentially Defunct Tetrahydrocannabinolic Acid Synthase Is a Marker for Cannabigerolic Acid Dominance in Cannabis sativa L." Genes 12, no. 2 (February 4, 2021): 228. http://dx.doi.org/10.3390/genes12020228.
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The regulation of cannabinoid synthesis in Cannabis sativa is of increasing research interest as restrictions around the globe loosen to allow the plant’s legal cultivation. Of the major cannabinoids, the regulation of cannabigerolic acid (CBGA) production is the least understood. The purpose of this study was to elucidate the inheritance of CBGA dominance in C. sativa and describe a marker related to this chemotype. We produced two crossing populations, one between a CBGA dominant cultivar and a tetrahydrocannabinolic acid (THCA) dominant cultivar, and one between a CBGA dominant cultivar and a cannabidiolic acid (CBDA) cultivar. Chemical and genotyping analyses confirmed that CBGA dominance is inherited as a single recessive gene, potentially governed by a non-functioning allelic variant of the THCA synthase. The “null” THCAS synthase contains a single nucleotide polymorphism (SNP) that may render the synthase unable to convert CBGA to THCA leading to the accumulation of CBGA. This SNP can be reliably used as a molecular marker for CBGA dominance in the selection and breeding of C. sativa.
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DINCER, A., Y. GUNES, and N. KARAKAYA. "Coal-based bottom ash (CBBA) waste material as adsorbent for removal of textile dyestuffs from aqueous solution." Journal of Hazardous Materials 141, no. 3 (March 22, 2007): 529–35. http://dx.doi.org/10.1016/j.jhazmat.2006.07.064.
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Burgel, Lisa, Jens Hartung, Annegret Pflugfelder, and Simone Graeff-Hönninger. "Impact of Growth Stage and Biomass Fractions on Cannabinoid Content and Yield of Different Hemp (Cannabis sativa L.) Genotypes." Agronomy 10, no. 3 (March 8, 2020): 372. http://dx.doi.org/10.3390/agronomy10030372.
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The medicinal use of cannabinoids renewed the interest in industrial hemp (Cannabis sativa L.). The aim of this study was to evaluate the impact of growth stage and biomass fractions of seven industrial hemp genotypes. The study focused on biomass yield, content of cannabidiolic acid/cannabidiol (CBDA/CBD), cannabigerolic acid/cannabigerol (CBGA/CBG), and tetrahydrocannabinolic acid (THCA). The experiment was conducted in 2017 and 2018. The biomass samples were taken at the vegetative (S1), bud (S2), full-flowering (S3) and seed maturity stage (S4). Plants were fractionated into inflorescence, upper and lower leaves. The average inflorescence dry yield of genotypes Futura75, Fédora17, Félina32 and Ferimon ranged between 257.28 g m−2 to 442.00 g m−2, resulting in a maximum yield of CBDA at S4, with 4568.26 mg m−2, 6011.20 mg m−2, 4975.60 mg m−2 and 1929.60 mg m−2, respectively. CBGA was exclusively found in genotype Santhica27, with a maximum CBGA yield of 5721.77 mg m−2 in inflorescence at growth stage S4 and a dry weight yield of 408.99 g m−2. Although these industrial hemp genotypes are mainly cultivated for fibre and seed production, however, cannabinoids offer an additional value. For an optimized harvest result, yield of extractable material and overall yield of cannabinoids must be considered.
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Elsaied, Hosam, and Takeshi Naganuma. "Phylogenetic Diversity of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Large-Subunit Genes from Deep-Sea Microorganisms." Applied and Environmental Microbiology 67, no. 4 (April 1, 2001): 1751–65. http://dx.doi.org/10.1128/aem.67.4.1751-1765.2001.
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ABSTRACT The phylogenetic diversity of the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO, E.C. 4.1.1.39) large-subunit genes of deep-sea microorganisms was analyzed. Bulk genomic DNA was isolated from seven samples, including samples from the Mid-Atlantic Ridge and various deep-sea habitats around Japan. The kinds of samples were hydrothermal vent water and chimney fragment; reducing sediments from a bathyal seep, a hadal seep, and a presumed seep; and symbiont-bearing tissues of the vent mussel, Bathymodiolus sp., and the seep vestimentiferan tubeworm, Lamellibrachia sp. The RuBisCO genes that encode both form I and form II large subunits (cbbL and cbbM) were amplified by PCR from the seven deep-sea sample DNA populations, cloned, and sequenced. From each sample, 50 cbbL clones and 50 cbbM clones, if amplified, were recovered and sequenced to group them into operational taxonomic units (OTUs). A total of 29 OTUs were recorded from the 300 total cbbL clones, and a total of 24 OTUs were recorded from the 250 total cbbM clones. All the current OTUs have the characteristic RuBisCO amino acid motif sequences that exist in other RuBisCOs. The recorded OTUs were related to different RuBisCO groups of proteobacteria, cyanobacteria, and eukarya. The diversity of the RuBisCO genes may be correlated with certain characteristics of the microbial habitats. The RuBisCO sequences from the symbiont-bearing tissues showed a phylogenetic relationship with those from the ambient bacteria. Also, the RuBisCO sequences of known species of thiobacilli and those from widely distributed marine habitats were closely related to each other. This suggests that theThiobacillus-related RuBisCO may be distributed globally and contribute to the primary production in the deep sea.
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Thompson, Richard M., and Robert T. Downs. "Systematic generation of all nonequivalent closest-packed stacking sequences of length N using group theory. Erratum." Acta Crystallographica Section B Structural Science 58, no. 1 (January 24, 2001): 153. http://dx.doi.org/10.1107/s0108768102000927.
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In the paper by Thompson & Downs (2001) the last line in Table 1 is missing. The correct table is reprinted here.The two nonequivalent sequences for N = 4 and their symmetrical equivalentsABAB ABAC ACAC ABCB BABA ACAB BCBC ACBC CACA BABC CBCB BACA BCBA BCAC CACB CABA CBCA CBAB
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Tourova, Tatjana P., Elizaveta M. Spiridonova, Ivan A. Berg, Boris B. Kuznetsov, and Dimitry Yu Sorokin. "Occurrence, phylogeny and evolution of ribulose-1,5-bisphosphate carboxylase/oxygenase genes in obligately chemolithoautotrophic sulfur-oxidizing bacteria of the genera Thiomicrospira and Thioalkalimicrobium." Microbiology 152, no. 7 (July 1, 2006): 2159–69. http://dx.doi.org/10.1099/mic.0.28699-0.
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The occurrence of the different genes encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), the key enzyme of the Calvin–Benson–Bassham cycle of autotrophic CO2 fixation, was investigated in the members of the genus Thiomicrospira and the relative genus Thioalkalimicrobium, all obligately chemolithoautotrophic sulfur-oxidizing Gammaproteobacteria. The cbbL gene encoding the ‘green-like’ form I RubisCO large subunit was found in all analysed species, while the cbbM gene encoding form II RubisCO was present only in Thiomicrospira species. Furthermore, species belonging to the Thiomicrospira crunogena 16S rRNA-based phylogenetic cluster also possessed two genes of green-like form I RubisCO, cbbL-1 and cbbL-2. Both 16S-rRNA- and cbbL-based phylogenies of the Thiomicrospira–Thioalkalimicrobium–Hydrogenovibrio group were congruent, thus supporting its monophyletic origin. On the other hand, it also supports the necessity for taxonomy reorganization of this group into a new family with four genera.
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Baker, Stefanie H., Songmu Jin, Henry C. Aldrich, Gary T. Howard, and Jessup M. Shively. "Insertion Mutation of the Form I cbbL Gene Encoding Ribulose Bisphosphate Carboxylase/Oxygenase (RuBisCO) in Thiobacillus neapolitanus Results in Expression of Form II RuBisCO, Loss of Carboxysomes, and an Increased CO2 Requirement for Growth." Journal of Bacteriology 180, no. 16 (August 15, 1998): 4133–39. http://dx.doi.org/10.1128/jb.180.16.4133-4139.1998.
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ABSTRACT It has been previously established that Thiobacillus neapolitanus fixes CO2 by using a form I ribulose bisphosphate carboxylase/oxygenase (RuBisCO), that much of the enzyme is sequestered into carboxysomes, and that the genes for the enzyme, cbbL and cbbS, are part of a putative carboxysome operon. In the present study, cbbL andcbbS were cloned and sequenced. Analysis of RNA showed thatcbbL and cbbS are cotranscribed on a message approximately 2,000 nucleotides in size. The insertion of a kanamycin resistance cartridge into cbbL resulted in a premature termination of transcription; a polar mutant was generated. The mutant is able to fix CO2, but requires a CO2supplement for growth. Separation of cellular proteins from both the wild type and the mutant on sucrose gradients and subsequent analysis of the RuBisCO activity in the collected fractions showed that the mutant assimilates CO2 by using a form II RuBisCO. This was confirmed by immunoblot analysis using antibodies raised against form I and form II RuBisCOs. The mutant does not possess carboxysomes. Smaller, empty inclusions are present, but biochemical analysis indicates that if they are carboxysome related, they are not functional, i.e., do not contain RuBisCO. Northern analysis showed that some of the shell components of the carboxysome are produced, which may explain the presence of these inclusions in the mutant.
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Liu, J. F., S. M. Mbadinga, X. B. Sun, G. C. Yang, S. Z. Yang, J. D. Gu, and B. Z. Mu. "Microbial communities responsible for fixation of CO<sub>2</sub> revealed by using <i>mcrA</i>, <i>cbbM</i>, <i>cbbL</i>, <i>fthfs</i>, <i>fefe-hydrogenase</i> genes as molecular biomarkers in petroleum reservoirs of different temperatures." Biogeosciences Discussions 12, no. 2 (January 30, 2015): 1875–906. http://dx.doi.org/10.5194/bgd-12-1875-2015.
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Abstract. Sequestration of CO2 in oil reservoir is one of the feasible options for mitigating atmospheric CO2 building up. The in situ bioconversion of sequestrated CO2 to methane by microorganisms inhabiting oil reservoirs is feasible. To evaluate the potential of in situ microbial fixation and conversion of CO2 into CH4 in oil reservoirs, a comprehensive molecular survey was performed to reveal microbial communities inhabiting four oil reservoirs with different temperatures by analysis of functional genes involved in the biochemical pathways of CO2 fixation and CH4 synthesis (cbbM, cbbL, fthfs, [FeFe]-hydrogenase encoding gene, and mcrA). A rich diversity of these functional genes was found in all the samples with both high and low temperatures and they were affiliated to members of the Proteobacteria (cbbL and cbbM, fthfs), Firmicutes and Actinobacteria (fthfs), uncultured bacteria ([FeFe]-hydrogenase), and Methanomirobiales, Methanobacteriales and Methanosarcinales (mcrA). The predominant methanogens were all identified to be hydrogenotrophic CO2-reducing physiological types. These results showed that functional microbial communities capable of microbial fixation and bioconversion of CO2 into methane inhabit widely in oil reservoirs, which is helpful to microbial recycling of sequestrated CO2 to further new energy in oil reservoirs.
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SÖZER, Edin Güçlü. "CUSTOMER BASED BRAND TOLERANCE (CBBT): SCALE DEVELOPMENT AND VALIDATION." Business & Management Studies: An International Journal 7, no. 5 (December 25, 2019): 2610–35. http://dx.doi.org/10.15295/bmij.v7i5.1339.
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In today’s markets, which are characterized with the strong competitive environment, successful customer retention is the ultimate target for all brands to survive. A strong Customer Based Brad Equity (CBBE) is an important competitive enabler which helps brands to generate satısfactory returns on their marketing investment and get them closer to their customer retention targets. However, this does not assure the unconditional retention and loyalty of consumers since the relationship is subject to continuous interactions between the brand and consumers which may eventually result in satisfactory as well as unsatisfactory customer experiences. This study contributes to the marketing literature by conceptualizing the Customer Based Brand Tolerance (CBBT) construct and develop and validate a scale which measures the CBBT strength of brands in a retailing context. In line with this target, the scale was developed and validated by following a three step procedure borrowed by the existing literature. Results confirm the three sub-dimensions of CBBT scale as Performance, Price and Communication Tolerance.
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Krivovichev, S. V., V. N. Yakovenchuk, E. S. Zhitova, A. A. Zolotarev, Y. A. Pakhomovsky, and G. Yu Ivanyuk. "Crystal chemistry of natural layered double hydroxides. I. Quintinite-2H-3c from the Kovdor alkaline massif, Kola peninsula, Russia." Mineralogical Magazine 74, no. 5 (October 2010): 821–32. http://dx.doi.org/10.1180/minmag.2010.074.5.821.
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AbstractThe crystal structure of quintinite-2H-3c, [Mg4Al2(OH)12](CO3)(H2O)3, from the Kovdor alkaline massif, Kola peninsula, Russia, was solved by direct methods and refined to an agreement index (R1) of 0.055 for 484 unique reflections with |Fo| ≥ 4σF. The mineral is rhombohedral, R32, a = 5.2745(7), c = 45.36(1) Å. The diffraction pattern of the crystal has strong and sharp Bragg reflections having h–k = 3n and l = 3n and lines of weak superstructure reflections extended parallel to c* and centred at h–k ≠ 3n. The structure contains six layers within the unit cell with the layer stacking sequence of …AC=CA=AC=CA=AC=CA… The Mg and Al atoms are ordered in metal hydroxide layers to form a honeycomb superstructure. The full superstructure is formed by the combination of two-layer stacking sequence and Mg-Al ordering. This is the first time that a long-range superstructure in carbonate-bearing layered double hydroxide (LDH) has been observed. Taking into account Mg-Al ordering, the unique layer sequence can be written as …=Ab1C=Cb1A=Ab2C=Cb2A=Ab3C=Cb3A=… The use of an additional suffix is proposed in order to distinguish between LDH polytypes having the same general stacking sequence but with different c parameters compared with the ‘standard’ polytype. According to this notation, the quintinite studied here can be described as quintinite-2H-3c or quintinite-2H-3c[6R], indicating the real symmetry.
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Beller, Harry R., Tracy E. Letain, Anu Chakicherla, Staci R. Kane, Tina C. Legler, and Matthew A. Coleman. "Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans under Aerobic versus Denitrifying Conditions." Journal of Bacteriology 188, no. 19 (October 1, 2006): 7005–15. http://dx.doi.org/10.1128/jb.00568-06.
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ABSTRACT Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with key chemolithoautotrophic functions (such as sulfur compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately 10% of the genome) as differentially expressed using RMA (robust multiarray average) statistical analysis and a twofold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb 3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated, respectively, with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription-quantitative PCR analysis was used to validate these trends.
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Toyoda, Koichi, Yoichi Yoshizawa, Hiroyuki Arai, Masaharu Ishii, and Yasuo Igarashi. "The role of two CbbRs in the transcriptional regulation of three ribulose-1,5-bisphosphate carboxylase/oxygenase genes in Hydrogenovibrio marinus strain MH-110." Microbiology 151, no. 11 (November 1, 2005): 3615–25. http://dx.doi.org/10.1099/mic.0.28056-0.
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Hydrogenovibrio marinus MH-110 possesses three different sets of genes for ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO): two form I (cbbLS-1 and cbbLS-2) and one form II (cbbM). We have previously shown that the expression of these RubisCO genes is dependent on the ambient CO2 concentration. LysR-type transcriptional regulators, designated CbbR1 and CbbRm, are encoded upstream of the cbbLS-1 and cbbM genes, respectively. In this study, we revealed by gel shift assay that CbbR1 and CbbRm bind with higher affinity to the promoter regions of cbbLS-1 and cbbM, respectively, and with lower affinity to the other RubisCO gene promoters. The expression patterns of the three RubisCOs in the cbbR1 and the cbbRm gene mutants showed that CbbR1 and CbbRm were required to activate the expression of cbbLS-1 and cbbM, respectively, and that neither CbbR1 nor CbbRm was required for the expression of cbbLS-2. The expression of cbbLS-1 was significantly enhanced under high-CO2 conditions in the cbbRm mutant, in which the expression of cbbM was decreased. Although cbbLS-2 was not expressed under high-CO2 conditions in the wild-type strain or the single cbbR mutants, the expression of cbbLS-2 was observed in the cbbR1 cbbRm double mutant, in which the expression of both cbbLS-1 and cbbM was decreased. These results indicate that there is an interactive regulation among the three RubisCO genes.
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Yoshizawa, Yoichi, Koichi Toyoda, Hiroyuki Arai, Masaharu Ishii, and Yasuo Igarashi. "CO2-Responsive Expression and Gene Organization of Three Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Enzymes and Carboxysomes in Hydrogenovibrio marinus Strain MH-110." Journal of Bacteriology 186, no. 17 (September 1, 2004): 5685–91. http://dx.doi.org/10.1128/jb.186.17.5685-5691.2004.
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ABSTRACT Hydrogenovibrio marinus strain MH-110, an obligately lithoautotrophic hydrogen-oxidizing bacterium, fixes CO2 by the Calvin-Benson-Bassham cycle. Strain MH-110 possesses three different sets of genes for ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO): CbbLS-1 and CbbLS-2, which belong to form I (L8S8), and CbbM, which belongs to form II (Lx). In this paper, we report that the genes for CbbLS-1 (cbbLS-1) and CbbM (cbbM) are both followed by the cbbQO genes and preceded by the cbbR genes encoding LysR-type regulators. In contrast, the gene for CbbLS-2 (cbbLS-2) is followed by genes encoding carboxysome shell peptides. We also characterized the three RubisCOs in vivo by examining their expression profiles in environments with different CO2 availabilities. Immunoblot analyses revealed that when strain MH-110 was cultivated in 15% CO2, only the form II RubisCO, CbbM, was expressed. When strain MH-110 was cultivated in 2% CO2, CbbLS-1 was expressed in addition to CbbM. In the 0.15% CO2 culture, the expression of CbbM decreased and that of CbbLS-1 disappeared, and CbbLS-2 was expressed. In the atmospheric CO2 concentration of approximately 0.03%, all three RubisCOs were expressed. Transcriptional analyses of mRNA by reverse transcription-PCR showed that the regulation was at the transcriptional level. Electron microscopic observation of MH-110 cells revealed the formation of carboxysomes in the 0.15% CO2 concentration. The results obtained here indicate that strain MH-110 adapts well to various CO2 concentrations by using different types of RubisCO enzymes.
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Gul, Waseem, Shahbaz W. Gul, Mohamed M. Radwan, Amira S. Wanas, Zlatko Mehmedic, Ikhlas I. Khan, Maged H. M. Sharaf, and Mahmoud A. ElSohly. "Determination of 11 Cannabinoids in Biomass and Extracts of Different Varieties of Cannabis Using High-Performance Liquid Chromatography." Journal of AOAC INTERNATIONAL 98, no. 6 (November 1, 2015): 1523–28. http://dx.doi.org/10.5740/jaoacint.15-095.
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Abstract An HPLC single-laboratory validation was performed for the detection and quantification of the 11 major cannabinoids in most cannabis varieties, namely, cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabidiol (CBD), tetrahydrocannabivarin (THCV), cannabinol (CBN), Δ9-trans-tetrahydrocannabinol (Δ9-THC), Δ8- trans-tetrahydrocannabinol (Δ8-THC), cannabicyclol (CBL), cannabichromene (CBC), and Δ9-tetrahydrocannabinolic acid-A (THCAA). The analysis was carried out on the biomass and extracts of these varieties. Methanol–chloroform (9:1, v/v) was used for extraction, 4-androstene-3,17-dione was used as the internal standard, and separation was achieved in 22.2 min on a C18 column using a two- step gradient elution. The method was validated for the 11 cannabinoids. The concentration-response relationship of the method indicated a linear relationship between the concentration and peak area with r2 values of >0.99 for all 11 cannabinoids. Method accuracy was determined through a spike study, and recovery ranged from 89.7 to 105.5% with an RSD of 0.19 to 6.32% for CBDA, CBD, THCV, CBN, Δ9-THC, CBL, CBC, and THCAA; recovery was 84.7, 84.2, and 67.7% for the minor constituents, CBGA, CBG, and Δ8-THC, respectively, with an RSD of 2.58 to 4.96%. The validated method is simple, sensitive, and reproducible and is therefore suitable for the detection and quantification of these cannabinoids in different types of cannabis plant materials.
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Li, Yang, Zhaojun Wu, Xingchen Dong, Zifu Xu, Qixin Zhang, Haiyan Su, Zhongjun Jia, and Qingye Sun. "Pyrite oxidization accelerates bacterial carbon sequestration in copper mine tailings." Biogeosciences 16, no. 2 (February 1, 2019): 573–83. http://dx.doi.org/10.5194/bg-16-573-2019.
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Abstract. Polymetallic mine tailings have great potential as carbon sequestration tools to stabilize atmospheric CO2 concentrations. However, previous studies focused on carbonate mineral precipitation, whereas the role of autotrophic bacteria in mine tailing carbon sequestration has been neglected. In this study, carbon sequestration in two samples of mine tailings treated with FeS2 was evaluated using 13C isotope, pyrosequencing and DNA-based stable isotope probing (SIP) analyses to identify carbon fixers. Mine tailings treated with FeS2 exhibited a higher percentage of 13C atoms (1.76±0.06 % for Yangshanchong and 1.36±0.01 % for Shuimuchong) than did controls over a 14-day incubation, which emphasized the role of autotrophs in carbon sequestration with pyrite addition. Pyrite treatment also led to changes in the composition of bacterial communities, and several autotrophic bacteria increased, including Acidithiobacillus and Sulfobacillus. Furthermore, pyrite addition increased the relative abundance of the dominant genus Sulfobacillus by 8.86 % and 5.99 % in Yangshanchong and Shuimuchong samples, respectively. Furthermore, DNA SIP results indicated a 8.20–16.50 times greater gene copy number for cbbL than cbbM in 13C-labeled heavy fractions, and a Sulfobacillus-like cbbL gene sequence (cbbL-OTU1) accounted for 30.11 %–34.74 % of all cbbL gene sequences in 13C-labeled heavy fractions of mine tailings treated with FeS2. These findings highlight the importance of the cbbL gene in bacterial carbon sequestration and demonstrate the ability of chemoautotrophs to sequester carbon during sulfide mineral oxidation in mine tailings. This study is the first to investigate carbon sequestration by autotrophic bacteria in mine tailings through the use of isotope tracers and DNA SIP.
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Cannon, Gordon C., Sabine Heinhorst, Christopher E. Bradburne, and Jessup M. Shively. "Carboxysome genomics: a status report." Functional Plant Biology 29, no. 3 (2002): 175. http://dx.doi.org/10.1071/pp01200.
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Carboxysomes, microcompartments that enhance the fixation of carbon dioxide by Rubisco, are found in several chemoautotrophs and in all cyanobacteria thus far examined. The genes for Rubisco large (cbbL) and small (cbbS) subunits (cbb for Calvin-Benson-Bassham), along with the genes (csoS) for the carboxysome shell peptides, are organized in a putative operon in Halothiobacillus neapolitanus in the following order: cbbL,cbbS, csoS2, csoS3, orfA, orfB, csoS1C, csoS1A, and csoS1B. DNA sequencing has revealed essentially the same operon in three other thiobacilli, Acidithiobacillus ferrooxidans, Thiomonas intermedia, and Thiobacillus denitrificans. The carboxysome genes are also clustered inSynechococcus sp. and Synechocystis sp., although in some cases certain genes lie outside the cluster. The genes, labelled ccm for CO2 concentrating mechanism, exist in Synechococcus PCC7942 in the order ccmK, ccmL, ccmM, ccmN, and ccmO, and are located upstream of the Rubisco genes. ccmO is absent, and multiple copies of ccmK exist in some species. The ccmK/ccmO and ccmL genes are homologues of csoS1CAB andorfAB, respectively. The ccmM and ccmN genes have no apparent counterpart in the thiobacilli. More recently, the genome sequence of four additional cyanobacteria has become available. The carboxysome genes in Nostoc punctiforme are clustered like, and are similar to, the genes of the earlier mentioned cyanobacteria. However, the three marine organisms Prochlorococcus marinus MIT9313, P. marinus MED4, and Synechococcus WH8102, possess an operon nearly identical to that found in thiobacilli. Furthermore, the genes exhibit surprising sequence identity to the carboxysome genes of the thiobacilli.
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Gibson, Janet L., James M. Dubbs, and F. Robert Tabita. "Differential Expression of the CO2 Fixation Operons of Rhodobacter sphaeroides by the Prr/Reg Two-Component System during Chemoautotrophic Growth." Journal of Bacteriology 184, no. 23 (December 1, 2002): 6654–64. http://dx.doi.org/10.1128/jb.184.23.6654-6664.2002.
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ABSTRACT In Rhodobacter sphaeroides, the two cbb operons encoding duplicated Calvin-Benson Bassham (CBB) CO2 fixation reductive pentose phosphate cycle structural genes are differentially controlled. In attempts to define the molecular basis for the differential regulation, the effects of mutations in genes encoding a subunit of Cbb3 cytochrome oxidase, ccoP, and a global response regulator, prrA (regA), were characterized with respect to CO2 fixation (cbb) gene expression by using translational lac fusions to the R. sphaeroides cbb I and cbbII promoters. Inactivation of the ccoP gene resulted in derepression of both promoters during chemoheterotophic growth, where cbb expression is normally repressed; expression was also enhanced over normal levels during phototrophic growth. The prrA mutation effected reduced expression of cbbI and cbbII promoters during chemoheterotrophic growth, whereas intermediate levels of expression were observed in a double ccoP prrA mutant. PrrA and ccoP1 prrA strains cannot grow phototrophically, so it is impossible to examine cbb expression in these backgrounds under this growth mode. In this study, however, we found that PrrA mutants of R. sphaeroides were capable of chemoautotrophic growth, allowing, for the first time, an opportunity to directly examine the requirement of PrrA for cbb gene expression in vivo under growth conditions where the CBB cycle and CO2 fixation are required. Expression from the cbbII promoter was severely reduced in the PrrA mutants during chemoautotrophic growth, whereas cbbI expression was either unaffected or enhanced. Mutations in ccoQ had no effect on expression from either promoter. These observations suggest that the Prr signal transduction pathway is not always directly linked to Cbb3 cytochrome oxidase activity, at least with respect to cbb gene expression. In addition, lac fusions containing various lengths of the cbbI promoter demonstrated distinct sequences involved in positive regulation during photoautotrophic versus chemoautotrophic growth, suggesting that different regulatory proteins may be involved. In Rhodobacter capsulatus, ribulose 1,5-bisphosphate carboxylase-oxygenase (RubisCO) expression was not affected by cco mutations during photoheterotrophic growth, suggesting that differences exist in signal transduction pathways regulating cbb genes in the related organisms.
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SINGH, TARKESHWAR, and PUNYASLOKE BHADURY. "Description of a new marine planktonic cyanobacterial species Synechococcus moorigangaii (Order Chroococcales) from Sundarbans mangrove ecosystem." Phytotaxa 393, no. 3 (February 22, 2019): 263. http://dx.doi.org/10.11646/phytotaxa.393.3.3.
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The genus Synechococcus is widespread across marine environments globally including in coastal habitats. In this study, culture of a new isolate (CMS01) of Synechococcus has been established and described based on polyphasic taxonomy from the world’s largest mangrove ecosystem, Sundarbans. This planktonic photoautrotroph has been proposed as a new species Synechococcus moorigangaii sp. nov. belonging to the order Chroococcales. The cells representing this proposed new species are solitary and can also form chain comprising of 4–6 cells. The shape of cell is oval to cylindrical and length ranges from 1.2–3 µm while the width ranges from 0.8–2 µm. The distribution pattern of photosynthetic filaments was found to be from the periphery of cell. Based on robust phylogeny of 16S rRNA, in addition to functional genes such as psbA, ureC, rbcL, and cbbA (multi gene phylogeny), the proposed new species differed from closest described species of Synechococcus under order Chroococcales. The fatty acid analysis indicated the presence of C12 and C14 chain fatty acids exclusive to isolate CMS01. The new isolate can grow across a range of salinity and in presence of different nitrogen sources. It has the ability to fix atmospheric di-nitrogen into ammonium ion. This new isolate of Synechococcus spp. is the first marine planktonic cyanobacterium described from a mangrove ecosystem and characterized using polyphasic approaches. Based on 16S rRNA phylogeny, this proposed new species clustered with Synechococcus strains PCC 7117, PCC 73109, PCC 7002, PCC 7003, PCC 7376 and NKNG15041c belonging to the order Chroococcales. The new species Synechococcus moorigangaii sp. nov. can serve as a model organism to understand ecophysiology and adaptation of planktonic cyanobacterial communities in mangrove ecosystems.
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Giupponi, Luca, Valeria Leoni, Radmila Pavlovic, and Annamaria Giorgi. "Influence of Altitude on Phytochemical Composition of Hemp Inflorescence: A Metabolomic Approach." Molecules 25, no. 6 (March 18, 2020): 1381. http://dx.doi.org/10.3390/molecules25061381.
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The phytochemical profiling of hemp inflorescences of clonal plants growing in different conditions related to altitude was investigated. Four strains of industrial hemp (Cannabis sativa L., family Cannabaceae) of Kompolti variety were selected and cloned to provide genetically uniform material for analyses of secondary metabolites (terpenes, cannabinoids, and flavonoids) at two different elevations: mountain (Alagna Valsesia 1200 m ASL) and plains (Vercelli Province 130 m ASL). Environmental conditions influenced by elevation have proven to be important factors inducing variations in hemp inflorescences’ secondary metabolite composition. In fact, all plants grown at altitude exhibited a higher total amount of terpenes when compared with plains counterparts, with β-Myrcene, trans-Caryophyllene and α-Humulene as the main contributors. A metabolomic, un-targeted approach performed by HPLC-Q-Exactive-Orbitrap®-MS platform with subsequent data processing performed by Compound Discoverer™ software, was crucial for the appropriate recognition of many metabolites, clearly distinguishing mountain from plains specimens. Cannabidiolic acid CBDA was the most abundant phytocannabinoid, with significantly higher concentrations in the mountain samples. The metabolic pathway of CBGA (considered as the progenitor/precursor of all cannabinoids) was also activated towards the production of CBCA, which occurs in considerably 3 times higher quantities than in the clones grown at high altitude. Isoprenoid flavones (Cannaflavins A, B, and C) were correspondingly upregulated in mountain samples, while apigenin turned out to be more abundant in plains samples. The possibility to use hemp inflorescences in pharmaceutical/nutraceutical applications opens new challenges to understand how hemp crops respond in terms of secondary metabolite production in various environments. In this regard, our results with the applied analytical strategy may constitute an effective way of phytochemical profiling hemp inflorescences.
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Thomas, Fabian Johannes, and Oliver Kayser. "Minor Cannabinoids of Cannabis sativa L." Journal of Medical Science 88, no. 3 (October 1, 2019): 141–49. http://dx.doi.org/10.20883/jms.367.
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Cannabinoids from Cannabis sativa L. play an important role as natural products in clinics. The major cannabinoids compromise tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) and its decarboxylated analogs. In this review, we focus on often neglected minor cannabinoids and discuss biosynthetic and chemical degradation routes to other neglected cannabinoids in Cannabis sativa starting from THCA, CBDA and cannabichromenic acid (CBCA). Based on the literature, patents and scientific reports, essential routes for the chemical modification of cannabinoids are discussed to explain chemical diversity chemical conversion and degradation by UV light, as well as temperature and pH leading to the formation of structurally unusual cannabinoids in planta called as minor cannabinoids. Based on known bioorganic reaction schemes and organic chemistry, principles for minor cannabinoid formation like [2+2] cycloaddition, Markonov condensation, radical introduction, or aromatization are discussed. Finally, the non-aqueous environment in Cannabis sativa trichomes is analyzed to clarify their role of a miniaturized bioreactors the light-induced conversion in a non-aqueous enviroment. The overall objective is to bridge from metabolic profiling via cannabinomics to structural and chemical diversity that allows the definition of patterns with consequences also to pharmacology and plant breeding.
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Giri, Bruno J., Nasreen Bano, and James T. Hollibaugh. "Distribution of RuBisCO Genotypes along a Redox Gradient in Mono Lake, California." Applied and Environmental Microbiology 70, no. 6 (June 2004): 3443–48. http://dx.doi.org/10.1128/aem.70.6.3443-3448.2004.
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ABSTRACT Partial sequences of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) (EC 4.1.1.39) genes were retrieved from samples taken along a redox gradient in alkaline, hypersaline Mono Lake, Calif. The form I gene (cbbL) was found in all samples, whereas form II (cbbM) was not retrieved from any of the samples. None of the RuBisCO sequences we obtained were closely related (nucleotide similarity, <90%) to sequences in the database. Some could be attributed to organisms isolated from the lake (Cyanobium) or appearing in enrichment cultures. Most (52%) of the sequences fell into in one clade, containing sequences that were identical to sequences retrieved from an enrichment culture grown with nitrate and sulfide, and another clade contained sequences identical to those retrieved from an arsenate-reducing, sulfide-oxidizing enrichment.
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Summers, Ryan, Sridhar Gopishetty, Sujit Mohanty, and Mani Subramanian. "New genetic insights to consider coffee waste as feedstock for fuel, feed, and chemicals." Open Chemistry 12, no. 12 (December 1, 2014): 1271–79. http://dx.doi.org/10.2478/s11532-014-0550-2.
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AbstractCaffeine is a natural plant product found in many drinks, including coffee, tea, soft and energy drinks. Due to caffeine’s presence in the environment, microorganisms have evolved two different mechanisms to live on caffeine. The genetic maps of the caffeine N-demethylation pathway and C-8 oxidation pathway have been discovered in Pseudomonas putida CBB5 and Pseudomonas sp. CBB1, respectively. These genes are the only characterized bacterial caffeine-degrading genes, and may be of great value in producing fine chemicals, biofuels, and animal feed from coffee and tea waste. Here, we present preliminary results for production of theobromine and 7-methylxanthine from caffeine and theobromine, respectively, by two strains of metabolically engineered E. coli. We also demonstrate complete decaffeination of tea extract by an immobilized mixed culture of Klebsiella and Rhodococcus cells. These processes provide a first level demonstration of biotechnological utilization of coffee and tea waste.
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Aldrich, H. C., S. Elvington, HE Machines, R. Szabady, K. Feder, L. McDowell, and J. M. Shively. "Ultrastructural and Cytochemical Analyses of the Expression of the Thiobacillus Carboxysome Operon in Escherichia Coli." Microscopy and Microanalysis 7, S2 (August 2001): 740–41. http://dx.doi.org/10.1017/s1431927600029779.
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The cytoplasm of the bacterium Thiobacillus neapolitanus contains 117 nm diameter polyhedral inclusions, “carboxysomes” (Fig. 1) that contain ribulose-1,5- bisphosphate carboxylase/oxygenase (RuBisCO). Surrounding the polyhedron are nonmembranous proteinaceous plates devoid of lipid. The carboxysomes are composed of at least 8 major peptides, all coded within the same operon. Six (CsoSIA, CsoSIB, CsoSIC, CsoS2A, CsoS2B, and CsoS3) make up the shell, and two are the large (CbbL) and small subunits (CbbS) of RuBisCO. Using immunogold labeling on ultrathin sections, peptides CsoS2A, CsoS2B, and CsoS3 have been localized to the shell. Since the original characterization of the csoSl gene, we have also immunolocalized the CsoSl peptide to the shell.As part of our initial efforts to understand how these components are assembled into the symmetrical, functional entity, the carboxysome operon from T. neapolitanus was cloned into the pET-21a(+) plasmid, an expression vector that codes for resistance to ampicillin.
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Sorokin, Dimitry Yu, Tatjana P. Tourova, Tatjana V. Kolganova, Elizaveta M. Spiridonova, Ivan A. Berg, and Gerard Muyzer. "Thiomicrospira halophila sp. nov., a moderately halophilic, obligately chemolithoautotrophic, sulfur-oxidizing bacterium from hypersaline lakes." International Journal of Systematic and Evolutionary Microbiology 56, no. 10 (October 1, 2006): 2375–80. http://dx.doi.org/10.1099/ijs.0.64445-0.
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Enrichments at 2 M NaCl and pH 7.5–8, with thiosulfate or sulfide as electron donor, inoculated with sediments from hypersaline chloride–sulfate lakes of the Kulunda Steppe (Altai, Russia) resulted in the domination of two different groups of moderately halophilic, chemolithoautotrophic, sulfur-oxidizing bacteria. Under fully aerobic conditions with thiosulfate, bacteria belonging to the genus Halothiobacillus dominated while, under microaerophilic conditions, a highly motile, short vibrio-shaped phenotype outcompeted the halothiobacilli. Three genetically and phenotypically highly similar vibrio-shaped isolates were obtained in pure culture and one of them, strain HL 5T, was identified as a member of the Thiomicrospira crunogena cluster by 16S rRNA gene sequencing. The new isolates were able to grow with thiosulfate as electron donor within a broad salinity range from 0.5 to 3.5 M NaCl with an optimum at 1.5 M and within a pH range from 6.5 to 8.5 with an optimum at pH 7.5–7.8. Comparative analysis of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) gene sequences demonstrated that strain HL 5T possessed two genes, cbbL-1 and cbbL-2, of the form I RuBisCO and a cbbM gene of the form II RuBisCO, similar to the other members of the Thiomicrospira crunogena cluster. On the basis of phenotypic and genetic comparison, the new halophilic isolates are proposed to be placed into a novel species, Thiomicrospira halophila sp. nov. (type strain HL 5T=DSM 15072T=UNIQEM U 221T).
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Gruber, Steffen, Helmut Schwab, and Petra Heidinger. "CbbR and RegA regulate cbb operon transcription in Ralstonia eutropha H16." Journal of Biotechnology 257 (September 2017): 78–86. http://dx.doi.org/10.1016/j.jbiotec.2017.07.005.
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Selesi, Draženka, Michael Schmid, and Anton Hartmann. "Diversity of Green-Like and Red-Like Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Large-Subunit Genes (cbbL) in Differently Managed Agricultural Soils." Applied and Environmental Microbiology 71, no. 1 (January 2005): 175–84. http://dx.doi.org/10.1128/aem.71.1.175-184.2005.
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ABSTRACT A PCR-based approach was developed to detect ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) form I large-subunit genes (cbbL) as a functional marker of autotrophic bacteria that fix carbon dioxide via the Calvin-Benson-Bassham cycle. We constructed two different primer sets, targeting the green-like and red-like phylogenetic groups of cbbL genes. The diversity of these cbbL genes was analyzed by the use of three differently managed agricultural soils from a long-term field experiment. cbbL gene fragments were amplified from extracted soil DNAs, and PCR products were cloned and screened by restriction fragment length polymorphism analysis. Selected unique cbbL clones were sequenced and analyzed phylogenetically. The green-like cbbL sequences revealed a very low level of diversity, being closely related to the cbbL genes of Nitrobacter winogradskyi and Nitrobacter vulgaris. In contrast, the red-like cbbL gene libraries revealed a high level of diversity in the two fertilized soils and less diversity in unfertilized soil. The majority of environmental red-like cbbL genes were only distantly related to already known cbbL sequences and even formed separate clusters. In order to extend the database of available red-like cbbL sequences, we amplified cbbL sequences from bacterial type culture strains and from bacterial isolates obtained from the investigated soils. Bacterial isolates harboring the cbbL gene were analyzed phylogenetically on the basis of their 16S rRNA gene sequences. These analyses revealed that bacterial genera such as Bacillus, Streptomyces, and Arthrobacter harbor red-like cbbL genes which fall into the cbbL gene clusters retrieved from the investigated soils.
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Schmith, Anika, Marco Groth, Josephine Ratka, Sara Gatz, Thomas Spaller, Oliver Siol, Gernot Glöckner, and Thomas Winckler. "Conserved Gene Regulatory Function of the Carboxy-Terminal Domain of Dictyostelid C-Module-Binding Factor." Eukaryotic Cell 12, no. 3 (January 25, 2013): 460–68. http://dx.doi.org/10.1128/ec.00329-12.
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ABSTRACT C-module-binding factor A (CbfA) is a jumonji-type transcription regulator that is important for maintaining the expression and mobility of the retrotransposable element TRE5-A in the social amoeba Dictyostelium discoideum . CbfA-deficient cells have lost TRE5-A retrotransposition, are impaired in the ability to feed on bacteria, and do not enter multicellular development because of a block in cell aggregation. In this study, we performed Illumina RNA-seq of growing CbfA mutant cells to obtain a list of CbfA-regulated genes. We demonstrate that the carboxy-terminal domain of CbfA alone is sufficient to mediate most CbfA-dependent gene expression. The carboxy-terminal domain of CbfA from the distantly related social amoeba Polysphondylium pallidum restored the expression of CbfA-dependent genes in the D. discoideum CbfA mutant, indicating a deep conservation in the gene regulatory function of this domain in the dictyostelid clade. The CbfA-like protein CbfB displays ∼25% sequence identity with CbfA in the amino-terminal region, which contains a JmjC domain and two zinc finger regions and is thought to mediate chromatin-remodeling activity. In contrast to CbfA proteins, where the carboxy-terminal domains are strictly conserved in all dictyostelids, CbfB proteins have completely unrelated carboxy-terminal domains. Outside the dictyostelid clade, CbfA-like proteins with the CbfA-archetypical JmjC/zinc finger arrangement and individual carboxy-terminal domains are prominent in filamentous fungi but are not found in yeasts, plants, and metazoans. Our data suggest that two functional regions of the CbfA-like proteins evolved at different rates to allow the occurrence of species-specific adaptation processes during genome evolution.
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Kumar, Ravi Shekhar, Satyabhusan Dash, and Naresh K. Malhotra. "The impact of marketing activities on service brand equity." European Journal of Marketing 52, no. 3/4 (April 9, 2018): 596–618. http://dx.doi.org/10.1108/ejm-05-2016-0262.
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Purpose This study aims to propose and empirically test new improved customer-based brand equity (CBBE) creation framework, which advocates marketing activities create CBBE through customer experience (CE). The proposed framework is in contrast to extant literature suggesting marketing activities directly create CBBE. Design/methodology/approach Qualitative interviews with patients, followed by interaction with respondents using a structured questionnaire, were used to collect the data. Findings The results suggest that CE is the focal mediating variable for the relationship between marketing activities and CBBE. Out of 15 marketing activities, 8 positively impacted CBBE through CE and 2 negatively affected CBBE through CE. Among the remaining five, three had only a direct positive impact on CBBE and two neither directly nor indirectly impacted CBBE. Research limitations/implications The effects of only individual marketing activity, and not of the interaction among marketing activities, were assessed. Practical implications The study provides insights into the importance of CE in building CBBE for credence-dominant services (e.g. healthcare). This work will help managers in implementing experiential marketing by designing suitable activities for creating service CBBE. Originality/value The study outlines service CBBE creation through CE, offering specific insights for the healthcare market.
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van Keulen, Geertje, Anja N. J. A. Ridder, Lubbert Dijkhuizen, and Wim G. Meijer. "Analysis of DNA Binding and Transcriptional Activation by the LysR-Type Transcriptional Regulator CbbR of Xanthobacter flavus." Journal of Bacteriology 185, no. 4 (February 15, 2003): 1245–52. http://dx.doi.org/10.1128/jb.185.4.1245-1252.2003.
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ABSTRACT The LysR-type transcriptional regulator CbbR controls the expression of the cbb and gap-pgk operons in Xanthobacter flavus, which encode the majority of the enzymes of the Calvin cycle required for autotrophic CO2 fixation. The cbb operon promoter of this chemoautotrophic bacterium contains three potential CbbR binding sites, two of which partially overlap. Site-directed mutagenesis and subsequent analysis of DNA binding by CbbR and cbb promoter activity were used to show that the potential CbbR binding sequences are functional. Inverted repeat IR1 is a high-affinity CbbR binding site. The main function of this repeat is to recruit CbbR to the cbb operon promoter. In addition, it is required for negative autoregulation of cbbR expression. IR3 represents the main low-affinity binding site of CbbR. Binding to IR3 occurs in a cooperative manner, since mutations preventing the binding of CbbR to IR1 also prevent binding to the low-affinity site. Although mutations in IR3 have a negative effect on the binding of CbbR to this site, they result in an increased promoter activity. This is most likely due to steric hindrance of RNA polymerase by CbbR since IR3 partially overlaps with the −35 region of the cbb operon promoter. Mutations in IR2 do not affect the DNA binding of CbbR in vitro but have a severe negative effect on the activity of the cbb operon promoter. This IR2 binding site is therefore critical for transcriptional activation by CbbR.
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Chenoweth, Matthew R., and Sue Wickner. "Complex Regulation of the DnaJ Homolog CbpA by the Global Regulators σS and Lrp, by the Specific Inhibitor CbpM, and by the Proteolytic Degradation of CbpM." Journal of Bacteriology 190, no. 15 (May 23, 2008): 5153–61. http://dx.doi.org/10.1128/jb.00437-08.
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ABSTRACT CbpA is a DnaJ homolog that functions as a DnaK cochaperone. Several cellular processes, including growth at low and high temperatures and septum formation during cell division, require either CbpA or DnaJ. CbpA is encoded in an operon with the gene for CbpM, which is a specific in vivo and in vitro inhibitor of CbpA. Here, we have cooverexpressed CbpA with CbpM in a ΔcbpAM ΔdnaJ strain and examined the resulting phenotypes. Under these conditions, sufficient free CbpA activity was present to support growth at low temperatures, but not at high temperatures. Defects in cell division and in λ replication were also partially complemented by CbpA when cooverexpressed with CbpM. Utilizing reporter fusions, we demonstrated that the cbpAM operon was maximally transcribed at the transition from exponential growth to stationary phase. Transcription was controlled by the σS and Lrp global regulators, and both leucine availability and growth temperature influenced transcription. CbpA and CbpM accumulated to similar levels in stationary phase, ∼2,300 monomers per cell. When not bound to CbpA, CbpM was unstable and was degraded by the Lon and ClpAP proteases. These data demonstrate that CbpA activity is controlled at multiple levels.
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Esmay, Paula A., Stephen J. Billington, Malen A. Link, J. Glenn Songer, and B. Helen Jost. "The Arcanobacterium pyogenes Collagen-Binding Protein, CbpA, Promotes Adhesion to Host Cells." Infection and Immunity 71, no. 8 (August 2003): 4368–74. http://dx.doi.org/10.1128/iai.71.8.4368-4374.2003.
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ABSTRACT Arcanobacterium pyogenes is an opportunistic pathogen associated with suppurative diseases in economically important food animals such as cattle, pigs, and turkeys. A. pyogenes adheres to host epithelial cells, and adhesion is promoted by the action of neuraminidase, which is expressed by this organism. However, a neuraminidase-deficient mutant of A. pyogenes only had a reduced ability to adhere to host epithelial cells, indicating that other factors are involved in adhesion. Far Western blotting revealed the presence of an approximately 120-kDa A. pyogenes cell wall protein that binds collagen type I. The 3.5-kb gene that encodes the 124.7-kDa CbpA protein was cloned, and sequence analysis indicated that CbpA contains a typical MSCRAMM protein domain structure. Recombinant, six-His-tagged CbpA (HIS-CbpA) was capable of binding collagen types I, II, and IV but not fibronectin. In addition, CbpA was involved in the ability of A. pyogenes to adhere to HeLa and 3T6 cells, as a cbpA knockout strain had 38.2 and 57.0% of wild-type adhesion, respectively. This defect could be complemented by providing cbpA on a multicopy plasmid. Furthermore, HIS-CbpA blocked A. pyogenes adhesion to HeLa or 3T6 cells in a dose-dependent manner. cbpA was only present in 48% of the A. pyogenes strains tested (n = 75), and introduction of plasmid-encoded cbpA into a naturally cbpA-deficient strain increased the ability of this strain to bind to HeLa and 3T6 cells 2.9- and 5.7-fold, respectively. These data indicate that CbpA, a collagen-binding protein of A. pyogenes, plays a role in the adhesion of this organism to host cells.
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Guo, Chenxi, and Ping Lv. "Network position of independent director in cross-border mergers and acquisitions." International Journal of Emerging Markets 13, no. 1 (January 15, 2018): 118–35. http://dx.doi.org/10.1108/ijoem-01-2017-0027.
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Purpose The purpose of this paper is to consider the impact of network position of independent directors on the decision-making process of cross-border mergers and acquisitions (CBMAs). Design/methodology/approach With 912 CBMAs constructed by 431 Chinese-listed corporations from 2006 to 2015, the authors provide graph-theoretical methods to quantify directors’ networks and build logistics models of CBMA success and generalized linear model for transaction value. Findings The authors find that independent directors in central positions of board networks of CBMA significantly strengthen the possibility of success of CBMA and react more positively to large CBMA. The results reveal that state-owned enterprises reduce the importance of independent directors in central positions in assisting successful CBMA, but strengthen the importance in promoting large CBMA. Specifically, majority shareholders counteract the importance of independent directors in central positions in assisting successful CBMA, but improve the importance in promoting large CBMA. Originality/value The findings suggest that independent directors in central positions, which are embedded in sets of board relationships and interactions, lead to efficient external corporate governance as a mechanism to facilitate a Chinese-listed firm’s CBMA decision making.
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Hoonsiri, Chinnawat, Siriluk Chiarakorn, and Vasin Kiattikomol. "Using Combined Bus Rapid Transit and Buses in a Dedicated Bus Lane to Enhance Urban Transportation Sustainability." Sustainability 13, no. 6 (March 10, 2021): 3052. http://dx.doi.org/10.3390/su13063052.
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Combined bus rapid transit and buses in a dedicated bus lane (CBBD) is a measure that bus rapid transit (BRT) operators implement to reduce overlapping routes between BRT and fixed-route buses. The CBBD measure can combine the passengers of both systems on the same route, which helps increase passenger demand for the BRT, and reduce fuel consumption and emissions from utilizing the exclusive lanes for the combined route. However, the CBBD could affect some bus and BRT passengers in terms of either losing or gaining travel time-saving benefits depending on their travel pattern. This research proposed a methodology to determine the travel distance initiating disadvantage for BRT passengers (DDB) to justify the potential success of the CBBD operations. The number of passengers gaining a benefit from the CBBD was sensitive to the distance between the CBBD stops and the operational period of the CBBD. The CBBD reform would be beneficial to transit agencies to improve the travel time of passengers and be able to promote environmental sustainability for the public transportation system in urban cities.
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Shimizu, Masami, Tetsuya Kimura, Takayoshi Koyama, Katsuhisa Suzuki, Naoto Ogawa, Kiyotaka Miyashita, Kazuo Sakka, and Kunio Ohmiya. "Molecular Breeding of Transgenic Rice Plants Expressing a Bacterial Chlorocatechol Dioxygenase Gene." Applied and Environmental Microbiology 68, no. 8 (August 2002): 4061–66. http://dx.doi.org/10.1128/aem.68.8.4061-4066.2002.
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ABSTRACT The cbnA gene encoding the chlorocatechol dioxygenase gene from Ralstonia eutropha NH9 was introduced into rice plants. The cbnA gene was expressed in transgenic rice plants under the control of a modified cauliflower mosaic virus 35S promoter. Western blot analysis using anti-CbnA protein indicated that the cbnA gene was expressed in leaf tissue, roots, culms, and seeds. Transgenic rice calluses expressing the cbnA gene converted 3-chlorocatechol to 2-chloromucote efficiently. Growth and morphology of the transgenic rice plants expressing the cbnA gene were not distinguished from those of control rice plants harboring only a Ti binary vector. It is thus possible to breed transgenic plants that degrade chloroaromatic compounds in soil and surface water.