PMID(sorted ascending)
chemical synthesis and biological screening of 2-aminoimidazole-based bacterial and fungal antibiofilm agents.a collection of 2-aminoimidazole/triazole amides has been synthesized and screened for antibiofilm activity. this class of small molecules was found to modulate the biofilm activity of pseudomonas aeruginosa, a multidrug-resistant strain of acinetobacter baumannii (mdrab), a methicillin-resistant staphylococcus aureus strain (mrsa), escherichia coli, rhodospirillum salexigens, staphylococcus epidermidis, vibrio vulnificus, and vancomycin-resistant enterococcus faecium as well as the yeast candid ...201020049758
an evolutionally conserved lys122 is essential for function in rhodospirillum rubrum bona fide rubisco and bacillus subtilis rubisco-like protein.ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) and rubisco-like protein (rlp) catalyze similar enolase-type reactions. both enzymes have a conserved non-catalytic lys122 or arg122 on the beta-strand e lying in the interface between the n- and c-terminal domains. we used site-directed mutagenesis to analyze the function of lys122 in the form ii rhodospirillum rubrum rubisco (rrrubisco) and bacillus subtilis rlp (bsrlp). the k122r mutant of rrrubisco had a 40% decrease in k(cat) for car ...201020060808
regulation of the ppr histidine kinase by light-induced interactions between its photoactive yellow protein and bacteriophytochrome domains.ppr is a unique bacteriophytochrome that bleaches rather than forming a far-red-shifted pfr state upon red light activation. ppr is also unusual in that it has a blue light photoreceptor domain, pyp, which is n-terminally fused to the bacteriophytochrome domain (bph). when both photoreceptors are activated by light, the fast phase of bph recovery (1 min lifetime) corresponds to the formation of an intramolecular long-lived complex between the activated pyp domain and the bph domain (lifetime of ...201020095642
excitation energy pathways in the photosynthetic units of reaction center lm- and h-subunit deletion mutants of rhodospirillum rubrum.light-induced reaction dynamics of isolated photosynthetic membranes obtained from wild-type (wt) and reaction center (rc)-subunit deletion strains spuhk1 (an h-subunit deletion mutant) and sk delta lm (an (l+m) deletion mutant) of the purple non-sulphur bacterium rhodospirillum rubrum have been investigated by femtosecond transient absorption spectroscopy. upon excitation of the spirilloxanthin (spx) s(2) state at 546 nm, of the bacteriochlorophyll soret band at 388 nm and probing spectral regi ...201020099080
exploring electron spin-spin interactions of paramagnetic iron and radical cations of bacteriochlorophyll from oxidized lh1 in the presence of electron transfer in the frozen state.cation free radicals of bacteriochlorophyll (bchl(+)) are formed in the light harvesting complex 1 (lh1) of photosynthetic bacteria upon oxidation by potassium ferricyanide. unusually narrow epr line widths are observed for bchl(+) in the frozen state. these narrow line widths are consistent with a molecular-wire behavior where rapid electron/hole transfer occurs between the bchl constituents of the pigment array responsible for light harvesting in bacterial photosynthesis. however, in addition ...201020151665
udp xylose synthase 1 is required for morphogenesis and histogenesis of the craniofacial skeleton.udp-xylose synthase (uxs1) is strongly conserved from bacteria to humans, but because no mutation has been studied in any animal, we do not understand its roles in development. furthermore, no crystal structure has been published. uxs1 synthesizes udp-xylose, which initiates glycosaminoglycan attachment to a protein core during proteoglycan formation. crystal structure and biochemical analyses revealed that an r233h substitution mutation in zebrafish uxs1 alters an arginine buried in the dimer i ...201020226781
characterization of triclosan-resistant mutants reveals multiple antimicrobial resistance mechanisms in rhodospirillum rubrum s1h.antimicrobial resistance mechanisms were identified in 11 spontaneous high- and low-level triclosan resistance (tcs(r)) mutants of rhodospirillum rubrum s1h by genotyping complemented with transcriptional analyses, antibiotic resistance screening, and membrane permeability analyses. high-end tcs(r) (mic = 8 mg/liter) was the result of a fabi1(g98v) mutation. this point mutation led to an even higher level of tcs(r) (mic > or = 16 mg/liter) in combination with constitutive upregulation of mexb an ...201020305019
toxicogenomic response of rhodospirillum rubrum s1h to the micropollutant the framework of the micro-ecological life support system alternative (melissa) project, a pilot study was performed to identify the effects of triclosan on the melissa carbon-mineralizing microorganism rhodospirillum rubrum s1h. triclosan is a biocide that is commonly found in human excrement and is considered an emerging pollutant in wastewater and the environment. chronic exposure to melissa-relevant concentrations (> or =25 microg liter(-1)) of triclosan resulted in a significant extensio ...201020363786
mutagenesis and functional characterization of the four domains of glnd, a bifunctional nitrogen sensor protein.glnd is a bifunctional uridylyltransferase/uridylyl-removing enzyme (utase/ur) and is believed to be the primary sensor of nitrogen status in the cell by sensing the level of glutamine in enteric bacteria. it plays an important role in nitrogen assimilation and metabolism by reversibly regulating the modification of p(ii) protein; p(ii) in turn regulates a variety of other proteins. glnd appears to have four distinct domains: an n-terminal nucleotidyltransferase (nt) domain; a central hd domain, ...201020363937
[cloning and molecular organization of the polyhydroxyalkanoic acid synthase gene (phac) of ralstonia eutropha strain b5786].class i polyhydroxyalkanoic acid (pha) synthase gene (phac) of ralstonia eutropha strain b5786 was cloned and characterized. r. eutropha b5786 features the ability to synthesize multicomponent phas with short- and medium-chain-length monomers from simple carbohydrate substrate. a correlation was made between the molecular structure of pha synthase and substrate specificity and the ability of strain-producers to accumulate phas of this or that structure. a strong similarity of pha synthase of r. ...201020391757
eukaryotic behaviour of a prokaryotic energy-transducing membrane: fully detached vesicular organelles arise by budding from the rhodobacter sphaeroides intracytoplasmic photosynthetic membrane.a major feature that distinguishes prokaryotic organisms from eukaryotes is their less complex internal structure, in which all membrane-associated functions are thought to be present within a continuous lipid-protein bilayer, rather than with distinct organelles. contrary to this notion, as described by tucker and co-workers in this issue of molecular microbiology, the application of cryo-electron tomography to the purple bacterium rhodobacter sphaeroides has demonstrated a heretofore unrecogni ...201020412442
membrane invagination in rhodobacter sphaeroides is initiated at curved regions of the cytoplasmic membrane, then forms both budded and fully detached spherical vesicles.the purple phototrophic bacteria synthesize an extensive system of intracytoplasmic membranes (icm) in order to increase the surface area for absorbing and utilizing solar energy. rhodobacter sphaeroides cells contain curved membrane invaginations. in order to study the biogenesis of icm in this bacterium mature (icm) and precursor (upper pigmented band - upb) membranes were purified and compared at the single membrane level using electron, atomic force and fluorescence microscopy, revealing fun ...201020444085
light-harvesting mechanism of bacteria exploits a critical interplay between the dynamics of transport and trapping.light-harvesting bacteria rhodospirillum photometricum were recently found to adopt strikingly different architectures depending on illumination conditions. we present analytic and numerical calculations which explain this observation by quantifying a dynamical interplay between excitation transfer kinetics and reaction center cycling. high light-intensity membranes exploit dissipation as a photoprotective mechanism, thereby safeguarding a steady supply of chemical energy, while low light-intens ...201020482023
phaeovibrio sulfidiphilus gen. nov., sp. nov., phototrophic alphaproteobacteria isolated from brackish water.two strains (ja480(t) and ja481) of phototrophic alphaproteobacteria were isolated from sediment samples collected from brackish water near nagapattinam, india. they were gram-negative, vibrioid cells containing bacteriochlorophyll a and rhodopin as major photosynthetic pigments. most cells of both strains were non-flagellated; 1 % of cells showed two monopolar flagella. cells showed positive phototaxis. both strains showed chimeric intracellular photosynthetic membranes, where both lamellar sta ...201120495036
metabolic flexibility revealed in the genome of the cyst-forming alpha-1 proteobacterium rhodospirillum centenum.rhodospirillum centenum is a photosynthetic non-sulfur purple bacterium that favors growth in an anoxygenic, photosynthetic n2-fixing environment. it is emerging as a genetically amenable model organism for molecular genetic analysis of cyst formation, photosynthesis, phototaxis, and cellular development. here, we present an analysis of the genome of this bacterium.201020500872
effects of ethanol, formaldehyde, and gentle heat fixation in confocal resonance raman microscopy of purple nonsulfur bacteria.resonance raman microscopy is well suited to examine living bacterial samples without further preparation. therefore, comparatively little thought has been given to its compatibility with common fixation methods. however, fixation of cell samples is a very important tool in the microbiological sciences, allowing the preservation of samples in a specific condition for further examination, future measurements, transport, or later reference. we examined the effects of three common fixatives-ethanol ...201120544803
tobacco biomass hydrolysate enhances coenzyme q10 production using photosynthetic rhodospirillum rubrum.coenzyme q10 (coq10), a potent antioxidative dietary supplement, was produced using a photosynthetic bacteria rhodospirillum rubrum atcc 25852 by submerged fermentation supplemented with tobacco biomass hydrolysate (tbh) in comparison with media supplemented with hydrolysates prepared with alfalfa (abh) or spinach (sbh). growth medium supplemented with 20% (v/v) tbh was found favorable with regard to cell density and coq10 concentration. the stimulation effects on cell growth (shortened lag phas ...201020554198
diazotrophic growth of rhodospirillum rubrum with 2-oxoglutarate as sole carbon source affects regulation of nitrogen metabolism as well as the soluble proteome.2-oxoglutarate plays a central role as a signal in the regulation of nitrogen metabolism in the phototrophic diazotroph rhodospirillum rubrum. in order to further study the role of this metabolite, we have constructed an r. rubrum strain that has the capacity to grow on 2-oxoglutarate as sole carbon source, in contrast to wild-type r. rubrum. this strain has the same growth characteristics as wild-type with malate as carbon source, but showed clear metabolic differences when 2-oxoglutarate was u ...201020600859
chaperonin-catalyzed rescue of kinetically trapped states in protein folding.groel and groes form a chaperonin nano-cage for single protein molecules to fold in isolation. the folding properties that render a protein chaperonin dependent are not yet understood. here, we address this question using a double mutant of the maltose-binding protein dm-mbp as a substrate. upon spontaneous refolding, dm-mbp populates a kinetically trapped intermediate that is collapsed but structurally disordered. introducing two long-range disulfide bonds into dm-mbp reduces the entropic foldi ...201020603018
coupling of collective motions of the protein matrix to vibrations of the non-heme iron in bacterial photosynthetic reaction centers.non-heme iron is a conservative component of type ii photosynthetic reaction centers of unknown function. we found that in the reaction center from rba. sphaeroides it exists in two forms, high and low spin ferrous states, whereas in rsp. rubrum mostly in a low spin state, in line with our earlier finding of its low spin state in the algal photosystem ii reaction center (burda et al., 2003). the temperature dependence of the non-heme iron displacement studied by mössbauer spectroscopy shows that ...201020603098
dimerisation of the rhodobacter sphaeroides rc-lh1 photosynthetic complex is not facilitated by a gxxxg motif in the pufx purple photosynthetic bacteria the initial steps of light energy transduction take place in an rc-lh1 complex formed by the photochemical reaction centre (rc) and the lh1 light harvesting pigment-protein. in rhodobacter sphaeroides, the rc-lh1 complex assembles in a dimeric form in which two rcs are surrounded by an s-shaped lh1 antenna. there is currently debate over the detailed architecture of this dimeric rc-lh1 complex, with particular emphasis on the location and precise function of a m ...201020646993
elimination of rubisco alters the regulation of nitrogenase activity and increases hydrogen production in rhodospirillum rubrum.nitrogenase not only reduces atmospheric nitrogen to ammonia, but also reduces protons to hydrogen (h(2)). the nitrogenase system is the primary means of h(2) production under photosynthetic and nitrogen-limiting conditions in many photosynthetic bacteria, including rhodospirillum rubrum. the efficiency of this biological h(2) production largely depends on the nitrogenase enzyme and the availability of atp and electrons in the cell. previous studies showed that blockage of the co(2) fixation pat ...201020652089
excitation transfer connectivity in different purple bacteria: a theoretical and experimental study.photosynthetic membranes accommodate densely packed light-harvesting complexes which absorb light and convey excitation to the reaction center (rc). the relationship between the fluorescence yield (phi) and the fraction (x) of closed rcs is informative about the probability for an excitation reaching a closed rc to be redirected to another rc. in this work, we have examined in this respect membranes from various bacteria and searched for a correlation with the arrangement of the light-harvesting ...201020655292
the specificity of proton-translocating transhydrogenase for nicotinamide its forward direction, transhydrogenase couples the reduction of nadp(+) by nadh to the outward translocation of protons across the membrane of bacteria and animal mitochondria. the enzyme has three components: di and diii protrude from the membrane and dii spans the membrane. hydride transfer takes place between nucleotides bound to di and diii. studies on the kinetics of a lag phase at the onset of a "cyclic reaction" catalysed by complexes of the di and diii components of transhydrogenase ...201120732298
time-dependent atomistic view on the electronic relaxation in light-harvesting system ii.aiming at a better understanding of the molecular details in light absorption during photosynthesis, spatial and temporal correlation functions as well as spectral densities have been determined. at the focus of the present study are the light-harvesting ii complexes of the purple bacterium rhodospirillum molischianum. the calculations are based on a time-dependent combination of molecular dynamics simulations and quantum chemistry methods. using a 12 ps long trajectory, different quantum chemic ...201020809619
[recent studies on gas sensors, cooa, fixl, and dos].heme-containing proteins, the heme proteins, are known to have physiologic functions in humans, mammalians, fish, plants, and bacteria. for example, hemoglobin and myoglobin, which belong to the globin family, have been studied in terms of their structures and functions with spectroscopic and mutagenic methods. recently, a new class of heme proteins has been discovered, referred to as gas sensors. these are heme-based sensor proteins that play important roles in transcriptional activation, histi ...201020823675
aniline-induced tryptophan production and identification of indole derivatives from three purple bacteria.growth on aniline by three purple non-sulfur bacteria (rhodospirillum rubrum atcc 11170, rhodobacter sphaeroides dsm 158, and rubrivivax benzoatiliticus ja2) as nitrogen, or carbon source could not be demonstrated. however in its presence, production of indole derivatives was observed with all the strains tested. at least 14 chromatographically (hplc) distinct peaks were observed at the absorption maxima of 275-280 nm from aniline induced cultures. five major indoles were identified based on hpl ...201020852980
the photosensor protein ppr of rhodocista centenaria is linked to the chemotaxis signalling pathway.rhodocista centenaria is a phototrophic α-proteobacterium exhibiting a phototactic behaviour visible as colony movement on agar plates directed to red light. as many phototrophic purple bacteria r. centenaria possesses a soluble photoactive yellow protein (pyp). it exists as a long fusion protein, designated ppr, consisting of three domains, the pyp domain, a putative bilin binding domain (bbd) and a histidine kinase domain (pph). the ppr protein is involved in the regulation of polyketide synth ...201021062468
sustaining n2-dependent growth in the presence of co.low levels of carbon monoxide inhibit the n(2)-dependent growth of rhodospirillum rubrum unless the ∼100-residue cown protein is expressed. expression requires the co-responsive regulator rcom and is maximal in cells grown in the presence of co and a poor nitrogen source, consistent with the role of cown in n(2) fixation.201021115659
two putative histidine kinases are required for cyst formation in rhodospirillum centenum.the photosynthetic bacterium, rhodospirillum centenum, has a flexible life cycle that permits it to survive starvation as dormant cyst cells. previous studies have identified some of the key regulators for encystment and demonstrated that the control of development is intricate. this complexity may arise from the need to integrate several environmental signals to mediate a switch from one mode of energy metabolism to another and to ensure that a transition to dormancy is initiated only when nece ...201021184217
cyclic gmp controls rhodospirillum centenum cyst development.adenylyl cyclases are widely distributed across all kingdoms whereas guanylyl cyclases are generally thought to be restricted to eukaryotes. here we report that the α-proteobacterium rhodospirillum centenum secretes cgmp when developing cysts and that a guanylyl cyclase deletion strain fails to synthesize cgmp and is defective in cyst formation. the r. centenum cyclase was purified and shown to effectively synthesize cgmp from gtp in vitro, demonstrating that it is a functional guanylyl cyclase. ...201121214648
bacterial genome chimaerism and the origin of mitochondria.many studies have sought to determine the origin and evolution of mitochondria. although the alphaproteobacteria are thought to be the closest relatives of the mitochondrial progenitor, there is dispute as to what its particular sister group is. some have argued that mitochondria originated from ancestors of the order rickettsiales, or more specifically of the rickettsiaceae family, while others believe that ancestors of the family rhodospirillaceae are also equally likely the progenitors. to re ...201121217797
a ctra homolog affects swarming motility and encystment in rhodospirillum centenum.the a-proteobacterium, rhodospirillum centenum, has a complex life cycle that allows adaptation to different environments. transitions between vegetative swim cell and swarmer cell types depend on whether the organism is growing in liquid surroundings or on a solid substrate. moreover, starvation can induce vegetative cells to differentiate into quiescent cysts. this paper describes the results of our investigation into the role of a putative dna-binding response regulator that is homologous to ...201121243338
camp, c-di-gmp, c-di-amp and now cgmp: bacteria use them all! 201121255104
ultrafast energy-transfer pathway in a purple-bacterial photosynthetic core antenna, as revealed by femtosecond time-resolved spectroscopy. 201021268203
biochemical characterization of a new type of intracellular phb depolymerase from rhodospirillum rubrum with high hydrolytic activity on native phb granules.a rhodospirillum rubrum gene that is predicted to code for an extracellular poly(3-hydroxybutyrate) (phb) depolymerase by the recently published polyhydroxyalkanoates (pha) depolymerase engineering database was cloned. the gene product (phaz3( rru )) was expressed in recombinant e. coli, purified and biochemically characterized. phaz3( rru ) turned out, however, to share characteristics of intracellular phb depolymerases and revealed a combination of properties that have not yet been described f ...201121274528
a glutathione redox effect on photosynthetic membrane expression in rhodospirillum rubrum.the formation of intracytoplasmic photosynthetic membranes by facultative anoxygenic photosynthetic bacteria has become a prime example for exploring redox control of gene expression in response to oxygen and light. although a number of redox-responsive sensor proteins and transcription factors have been characterized in several species during the last several years in some detail, the overall understanding of the metabolic events that determine the cellular redox environment and initiate redox ...201121317329
thermostability of rhodopseudomonas viridis and rhodospirillum rubrum chromatophores reflecting physiological conditions.relationships between growth conditions and thermostability were examined for photosynthetic inner membranes (chromatophores) from rhodopseudomonas viridis and rhodospirillum rubrum of which morphology, lipid composition, and protein/lipid rate are rather mutually different. signals observed by differential scanning calorimetry of the chromatophores were correlated with thermal state transitions of the membrane components by reference to temperature dependencies of circular dichroism and absorpt ...201121354412
dark excited states of carotenoid regulated by bacteriochlorophyll in photosynthetic light photosynthesis, carotenoids play important roles in light harvesting (lh) and photoprotective functions, which have been described mainly in terms of two singlet excited states of carotenoids: s(1) and s(2). in addition to the "dark" s(1) state, another dark state, s*, was recently identified and its involvement in photosynthetic functions was determined. however, there is no consistent picture concerning its nature or the mechanism of its formation. one particularly anomalous behavior obtain ...201121388114
effect of pyruvate on the metabolic regulation of nitrogenase activity in rhodospirillum rubrum in darkness.rhodospirillum rubrum, a photosynthetic diazotroph, is able to regulate nitrogenase activity in response to environmental factors such as ammonium ions or darkness, the so-called switch-off effect. this is due to reversible modification of the fe-protein, one of the two components of nitrogenase. the signal transduction pathway(s) in this regulatory mechanism is not fully understood, especially not in response to darkness. we have previously shown that the switch-off response and metabolic state ...201121393366
ab inito study on triplet excitation energy transfer in photosynthetic light-harvesting complexes.we have studied the triplet energy transfer (tet) for photosynthetic light-harvesting complexes, the bacterial light-harvesting complex ii (lh2) of rhodospirillum molischianum and rhodopseudomonas acidophila, and the peridinin-chlorophyll a protein (pcp) from amphidinium carterae. the electronic coupling factor was calculated with the recently developed fragment spin difference scheme (you and hsu, j. chem. phys. 2010, 133, 074105), which is a general computational scheme that yields the overall ...201121410281
identification of chromatophore membrane protein complexes formed under different nitrogen availability conditions in rhodospirillum rubrum.the chromatophore membrane of the photosynthetic diazotroph rhodospirillum rubrum is of vital importance for a number of central processes, including nitrogen fixation. using a novel amphiphile, we have identified protein complexes present under different nitrogen availability conditions by the use of two-dimensional blue native/sds-page and nsi-lc-ltq-orbitrap mass spectrometry. we have identified several membrane protein complexes, including components of the atp synthase, reaction center, lig ...201121443180
the poor growth of rhodospirillum rubrum mutants lacking rubisco is due to the accumulation of ribulose-1, 5-bisphosphate.ribulose-1, 5-bisphosphate carboxylase/oxygenase (rubisco) catalyzes the first step of co(2) fixation in the calvin-benson-bassham (cbb) cycle. besides its function in fixing co(2) to support photoautotrophic growth, the cbb cycle is also important under photoheterotrophic growth conditions in purple nonsulfur photosynthetic bacteria. it has been assumed that the poor photoheterotrophic growth of rubisco-deficient strains was due to the accumulation of excess intracellular reductant, which impli ...201121531802
shedding light on selenium biomineralization: proteins associated with bionanominerals.selenium reducing microorganisms produce elemental selenium nanoparticles with particular physico-chemical properties being due to an associated organic fraction. this study identified high affinity proteins being associated with such bionanominerals and with non-biogenic elemental selenium. proteins with an anticipated functional role in selenium reduction, such as a metalloid reductase, were found associated with nanoparticles formed by one selenium respirer, sulfurospirillum barnesii.201121602371
in silico predictions of lh2 ring sizes from the crystal structure of a single subunit using molecular dynamics simulations.most of the currently known light-harvesting complexes 2 (lh2) rings are formed by 8 or 9 subunits. as of now, questions like "what factors govern the lh2 ring size?" and "are there other ring sizes possible?" remain largely unanswered. here, we investigate by means of molecular dynamics (md) simulations and stochastic modeling the possibility of predicting the size of an lh2 ring from the sole knowledge of the high resolution crystal structure of a single subunit. starting with single subunits ...201121604304
forces guiding assembly of light-harvesting complex 2 in native membranes.interaction forces of membrane protein subunits are of importance in their structure, assembly, membrane insertion, and function. in biological membranes, and in the photosynthetic apparatus as a paradigm, membrane proteins fulfill their function by ensemble actions integrating a tight assembly of several proteins. in the bacterial photosynthetic apparatus light-harvesting complexes 2 (lh2) transfer light energy to neighboring tightly associated core complexes, constituted of light-harvesting co ...201121606335
complete genome sequence of rhodospirillum rubrum type strain (s1).rhodospirillum rubrum (esmarch 1887) molisch 1907 is the type species of the genus rhodospirillum, which is the type genus of the family rhodospirillaceae in the class alphaproteobacteria. the species is of special interest because it is an anoxygenic phototroph that produces extracellular elemental sulfur (instead of oxygen) while harvesting light. it contains one of the most simple photosynthetic systems currently known, lacking light harvesting complex 2. strain s1(t) can grow on carbon monox ...201121886856
site-specific genome integration in alphaproteobacteria mediated by tg1 integrase.the serine-type phage integrase is an enzyme that catalyzes site-specific recombination between two attachment sites of phage and host bacterial genomes (attp and attb, respectively) having relatively short but distinct sequences without host auxiliary factor(s). previously, we have established in vivo and in vitro site-specific recombination systems based on the serine-type integrase produced by actinophage tg1 and determined the minimal sizes of attp ( tg1 ) and attb ( tg1 ) sites required for ...201121887508
Metabolic network modeling of redox balancing and biohydrogen production in purple nonsulfur bacteria.Purple nonsulfur bacteria (PNSB) are facultative photosynthetic bacteria and exhibit an extremely versatile metabolism. A central focus of research on PNSB dealt with the elucidation of mechanisms by which they manage to balance cellular redox under diverse conditions, in particular under photoheterotrophic growth.201121943387
evolution of vacuolar proton pyrophosphatase domains and volutin granules: clues into the early evolutionary origin of the acidocalcisome.volutin granules appear to be universally distributed and are morphologically and chemically identical to acidocalcisomes, which are electron-dense granular organelles rich in calcium and phosphate, whose functions include storage of phosphorus and various metal ions, metabolism of polyphosphate, maintenance of intracellular ph, osmoregulation and calcium homeostasis. prokaryotes are thought to differ from eukaryotes in that they lack membrane-bounded organelles. however, it has been demonstrate ...201121974828
Novel substrate (algal protein) for cultivation of Rhodospirillum rubrum.Rhodospirillum rubrum was grown under light anaerobic conditions with phycocyanin (C-pc) extracted from Spirulina platensis as the sole source of carbon and nitrogen. When grown under these conditions cellular components like lipids, carbohydrates, protein, carotenoids, bacteriochlorophyll were similar to the one grown with malic acid and ammonium chloride. Growth of R. rubrum increased with increase in concentration of C-pc (200 to 1000 mg/l). R. rubrum also utilized C-pc under dark anaerobic c ...201122013744
identification of a new gene required for the biosynthesis of rhodoquinone in rhodospirillum rubrum.rhodoquinone (rq) is a required cofactor for anaerobic respiration in rhodospirillum rubrum, and it is also found in several helminth parasites that utilize a fumarate reductase pathway. rq is an aminoquinone that is structurally similar to ubiquinone (q), a polyprenylated benzoquinone used in the aerobic respiratory chain. rq is not found in humans or other mammals, and therefore inhibition of its biosynthesis may provide a novel anti-parasitic drug target. to identify a gene specifically requi ...201122194448
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