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Christopher W Jones, Judith P Armitage
Bacterial chemosensory proteins form large hexagonal arrays. Several key feature of chemotactic signalling depend on these large arrays, namely cooperativity between receptors, sensitivity, integration of different signals and adaptation. The best studied arrays are the membrane associated arrays found in most bacteria. Rhodobacter sphaeroides has two spatially distinct chemosensory arrays, one transmembrane and the other cytoplasmic. These two arrays work together to control a single flagellum. Deletion of one of the soluble chemoreceptors, TlpT, results in the loss of formation of the cytoplasmic array...
July 24, 2017: Journal of Bacteriology
Emrah Sagir, Ebru Ozgur, Ufuk Gunduz, Inci Eroglu, Meral Yucel
Biohydrogen production via fermentative routes offers considerable advantages in waste recycling and sustainable energy production. This can be realized by single-stage dark or photofermentative processes, or by a two-stage integrated process; the latter offering the higher production yields due to complete conversion of sugar substrates into H2 and CO2. However, problems arising from the integration of these two processes limit its scale-up and implementation. Hence, high efficiency one-step fermentative biohydrogen production processes from sugar-rich wastes are preferable...
July 20, 2017: Bioprocess and Biosystems Engineering
Kaitlyn M Faries, Nicholas P Dylla, Deborah K Hanson, Dewey Holten, Philip D Laible, Christine Kirmaier
Seemingly redundant parallel pathways for electron transfer (ET), composed of identical sets of cofactors, are a cornerstone feature of photosynthetic reaction centers (RCs) involved in light-energy conversion. In native bacterial RCs, both A and B branches house one bacteriochlorophyll (BChl) and one bacteriopheophytin (BPh), but the A branch is used exclusively. Described herein are the results obtained for two Rhodobacter capsulatus RCs with an unnaturally high degree of cofactor asymmetry, two BPh on the RC's B side and two BChl on the A side...
July 17, 2017: Journal of Physical Chemistry. B
Vilma Pérez, Martha Hengst, Lenka Kurte, Cristina Dorador, Wade H Jeffrey, Ruddy Wattiez, Veronica Molina, Sabine Matallana-Surget
Salar de Huasco, defined as a polyextreme environment, is a high altitude saline wetland in the Chilean Altiplano (3800 m.a.s.l.), permanently exposed to the highest solar radiation doses registered in the world. We present here the first comparative proteomics study of a photoheterotrophic bacterium, Rhodobacter sp., isolated from this remote and hostile habitat. We developed an innovative experimental approach using different sources of radiation (in situ sunlight and UVB lamps), cut-off filters (Mylar, Lee filters) and a high-throughput, label-free quantitative proteomics method to comprehensively analyze the effect of seven spectral bands on protein regulation...
2017: Frontiers in Microbiology
Daria Elkina, Lennart Weber, Marcus Lechner, Olga Burenina, Andrea Weisert, Elena Kubareva, Roland K Hartmann, Gabriele Klug
The function of 6S RNA, a global regulator of transcription, was studied in the photosynthetic α-proteobacterium Rhodobacter sphaeroides. The cellular levels of R. sphaeroides 6S RNA peak toward the transition to stationary phase and strongly decrease during extended stationary phase. The synthesis of so-called product RNA transcripts (mainly 12-16-mers) on 6S RNA as template by RNA polymerase was found to be highest in late exponential phase. Product RNA ≥ 13-mers are expected to trigger the dissociation of 6S RNA:RNA polymerase complexes...
July 10, 2017: RNA Biology
Parmeshwar B Katare, Pankaj K Bagul, Amit K Dinda, Sanjay K Banerjee
BACKGROUND: Inflammation remains a crucial factor for progression of cardiac diseases and cardiac hypertrophy remains an important cause of cardiac failure over all age groups. As a key regulator of inflammation, toll-like receptor 4 (TLR4) plays an important role in pathogenesis of cardiac diseases. Being an important regulator of innate immunity, the precise pathway of TLR4-mediated cardiac complications is yet to be established. Therefore, the primary objective of the present study was to find the role of TLR4 in cardiac hypertrophy and the molecular mechanism thereof...
2017: Frontiers in Immunology
Enchao Li, Rongchang Wang, Xuewen Jin, Shuguang Lu, Zhaofu Qiu, Xiang Zhang
Global water shortages have resulted in increasing interest in water reuse and recycling. Therefore, in the present study, a biological denitrifying process using a sequencing batch reactor (SBR) was employed to treat reverse osmosis (RO) concentrate with high conductivity produced from a coking wastewater plant. From the results, the average removal efficiencies for chemical oxygen demand, total nitrogen, and nitrate were 79.5%, 90.5%, and 93.1%, respectively. Different microbial communities were identified after sequencing the V1-V3 region of the 16S rRNA gene using the MiSeq platform, and the major bacterial phyla in the SBR system were Proteobacteria and Bacteroidetes...
July 6, 2017: Environmental Technology
Hyunmin Koo, Joseph A Hakim, Casey D Morrow, Peter G Eipers, Alfonso Davila, Dale T Andersen, Asim K Bej
In this study, using NextGen sequencing of the collective 16S rRNA genes obtained from two sets of samples collected from Lake Obersee, Antarctica, we compared and contrasted two bioinformatics tools, PICRUSt and Tax4Fun. We then developed an R script to assess the taxonomic and predictive functional profiles of the microbial communities within the samples. Taxa such as Pseudoxanthomonas, Planctomycetaceae, Cyanobacteria Subsection III, Nitrosomonadaceae, Leptothrix, and Rhodobacter were exclusively identified by Tax4Fun that uses SILVA database; whereas PICRUSt that uses Greengenes database uniquely identified Pirellulaceae, Gemmatimonadetes A1-B1, Pseudanabaena, Salinibacterium and Sinobacteraceae...
June 24, 2017: Journal of Microbiological Methods
Kai Tang, Dan Lin, Qiang Zheng, Keshao Liu, Yujie Yang, Yu Han, Nianzhi Jiao
BACKGROUND: Marine phages are spectacularly diverse in nature. Dozens of roseophages infecting members of Roseobacter clade bacteria were isolated and characterized, exhibiting a very high degree of genetic diversity. In the present study, the induction of two temperate bacteriophages, namely, vB_ThpS-P1 and vB_PeaS-P1, was performed in Roseobacter clade bacteria isolated from the deep-sea water, Thiobacimonas profunda JLT2016 and Pelagibaca abyssi JLT2014, respectively. Two novel phages in morphological, genomic and proteomic features were presented, and their phylogeny and evolutionary relationships were explored by bioinformatic analysis...
June 27, 2017: BMC Genomics
Martin Godány, Bhavin S Khatri, Richard A Goldstein
Although the "adaptive" strategy used by Escherichia coli has dominated our understanding of bacterial chemotaxis, the environmental conditions under which this strategy emerged is still poorly understood. In this work, we study the performance of various chemotactic strategies under a range of stochastic time- and space-varying attractant distributions in silico. We describe a novel "speculator" response in which the bacterium compare the current attractant concentration to the long-term average; if it is higher then they tumble persistently, while if it is lower than the average, bacteria swim away in search of more favorable conditions...
2017: PloS One
Sara Granafei, Ilario Losito, Massimo Trotta, Angela Agostiano, Francesco Palmisano, Tommaso R I Cataldi
Cardiolipins (CL) contained in the lipid extracts of the photosynthetic bacterium Rhodobacter sphaeroides (strain R26) were systematically characterized by reversed-phase liquid chromatography coupled to electrospray ionization mass spectrometry, performed in single (MS), tandem (MS/MS) and sequential (MS(3)) modes using a linear ion trap mass spectrometer. The total number of carbon atoms and C=C bonds of each CL and, subsequently, those related to each of the constituting phosphatidic acid (PA) units, along with the location of the latter on the central glycerol backbone, were inferred from MS and MS/MS data, respectively...
June 20, 2017: Analytical and Bioanalytical Chemistry
Andreia F Verisssimo, Bahia Khalfaoui-Hassani, Josephine Hwang, Stefan Steimle, Nur Selamoglu, Carsten Sanders, Camilo Khatchikian, Fevzi Daldal
In many Gram-negative bacteria, including Rhodobacter capsulatus, cytochrome c maturation (Ccm) is carried out by a membrane-integral machinery composed of nine proteins (CcmA to I). During this process, the periplasmic thiol-disulfide oxidoreductase DsbA is thought to catalyze the formation of a disulfide bond between the Cys residues at the apocytochrome c heme binding site (CXXCH). Subsequently, a Ccm-specific thioreductive pathway involving CcmG and CcmH reduces this disulfide bond to allow covalent heme ligation...
June 20, 2017: Journal of Biological Chemistry
Terukazu Sanui, Masaaki Takeshita, Takao Fukuda, Urara Tanaka, Rehab Alshargabi, Yoshitomi Aida, Fusanori Nishimura
Tripalmitoyl-S-glyceryl-l-Cys-Ser-(Lys)4 (Pam3CSK4) is a highly conserved molecular motif found in various classes of lipoproteins. The requirement for leukocyte to respond to synthetic Pam3CSK4 were studied. Pam3CSK4 primed neutrophils for a respiratory burst in a serum-dependent manner. Pam3CSK4 upregulated CD11b, CD14, and cytochrome b558, and downregulated Leu-8. Treatment of neutrophils with anti-CD14 antibodies and treatment of serum with anti-LPS binding protein (LBP) antibodies resulted in the inhibition of priming for respiratory burst by Pam3CSK4...
June 17, 2017: International Immunopharmacology
Xiaomin Li, Weihua Peng, Yingying Jia, Lin Lu, Wenhong Fan
Rhodobacter sphaeroides was used for bioremediation of wastewater polluted with cadmium (Cd) and zinc (Zn). The tolerance of the microorganism to selected heavy metals (HMs), as well as the effects of pH, temperature and inoculum size on the removal rate, was investigated. The remediation effects of R. sphaeroides were analysed at different initial concentrations of HMs. Bioremediation mechanisms were thoroughly discussed based on the results from the cell characterisation analysis. Cd and Zn could inhibit the growth of R...
June 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Cheng-Hua Wang, Chong Zhang, Xin-Hui Xing
The aim of this work was to demonstrate the first proof-of-concept for the use of ab initio-aided assembly strategy intensifying in vivo biosynthesis process to construct Escherichia coli cell factory overproducing highly active xanthine dehydrogenase (XDH). Three global regulator (IscS, TusA and NarJ) and four chaperone proteins (DsbA, DsbB, NifS and XdhC) were overexpressed to aid the formation and ordered assembly of three redox center cofactors of Rhodobacter capsulatus XDH in E. coli. The NifS, IscS and DsbB enhanced the specific activity of RcXDH by 30%, 94% and 49%, respectively...
May 31, 2017: Bioresource Technology
Sarthak Mandal, Anne-Marie Carey, Joshua Locsin, Bing-Rong Gao, JoAnn C Williams, James P Allen, Su Lin, Neal W Woodbury
In purple bacterial reaction centers, triplet excitation energy transfer occurs from the primary donor P, a bacteriochlorophyll dimer, to a neighboring carotenoid to prevent photodamage from the generation of reactive oxygen species. The BB bacteriochlorophyll molecule that lies between P and the carotenoid on the inactive electron transfer branch is involved in triplet energy transfer between P and the carotenoid. To expand the high-resolution spectral and kinetic information available for describing the mechanism, we investigated the triplet excited state formation and energy transfer pathways in the reaction center of Rhodobacter sphaeroides using pump-probe transient absorption spectroscopy over a broad spectral region on the nanosecond to microsecond time scale at both room temperature and at 77 K...
June 27, 2017: Journal of Physical Chemistry. B
R A Khatypov, A M Khristin, T Yu Fufina, V A Shuvalov
In the absorption spectrum of Rhodobacter sphaeroides reaction centers, a minor absorption band was found with a maximum at 1053 nm. The amplitude of this band is ~10,000 times less and its half-width is comparable to that of the long-wavelength absorption band of the primary electron donor P870. When the primary electron donor is excited by femtosecond light pulses at 870 nm, the absorption band at 1053 nm is increased manifold during the earliest stages of charge separation. The growth of this absorption band in difference absorption spectra precedes the appearance of stimulated emission at 935 nm and the appearance of the absorption band of anion-radical BA(-) at 1020 nm, reported earlier by several researchers...
June 2017: Biochemistry. Biokhimii︠a︡
E P Petushkova, A A Tsygankov
The purple non-sulfur bacterium Rhodobacter capsulatus B10 can grow on acetate as the sole carbon source under photoheterotrophic conditions. It is known that the bacterium can use the glyoxylate cycle and, in addition to it, or alternatively to it, an unknown pathway for acetate assimilation. We analyzed the genetic potential for functioning of additional metabolic pathways of oxaloacetic acid (OAA) pool replenishment in R. capsulatus. Using published microarray data of more than 4000 transcripts of genes for R...
May 2017: Biochemistry. Biokhimii︠a︡
Alexander B Westbye, J Thomas Beatty, Andrew S Lang
Gene transfer agents (GTAs) are bacteriophage-like particles produced by many prokaryotes. Several members of the Alphaproteobacteria produce a class of genetically-related GTAs that is best studied in Rhodobacter capsulatus. DNA transfer by the R. capsulatus GTA (RcGTA) combines aspects of both transduction and natural transformation, as recipient cells require a natural transformation-like system to incorporate donated DNA. The genes involved in RcGTA production and recipient capability are located at multiple loci in the bacterial genome; however, a conserved phosphorelay containing the response regulator CtrA and a quorum sensing system regulate both RcGTA production and recipient capability...
June 6, 2017: Current Opinion in Microbiology
Pu Qian, Elizabeth C Martin, Irene W Ng, C Neil Hunter
In bacterial photosynthesis reaction center-light-harvesting 1 (RC-LH1) complexes trap absorbed solar energy by generating a charge separated state. Subsequent electron and proton transfers form a quinol, destined to diffuse to the cytochrome bc1 complex. In bacteria such as Rhodobacter (Rba.) sphaeroides and Rba. capsulatus the PufX polypeptide creates a channel for quinone/quinol traffic across the LH1 complex that surrounds the RC, and it is therefore essential for photosynthetic growth. PufX also plays a key role in dimerization of the RC-LH1-PufX core complex, and the structure of the Rba...
June 3, 2017: Biochimica et Biophysica Acta
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