Publications

TitleAbstractYear
Filter
PMID(sorted ascending)
Filter
squalene-hopene cyclases.hopanoids and sterols are members of a large group of cyclic triterpenoic compounds that have important functions in many prokaryotic and eukaryotic organisms. they are biochemically synthesized from linear precursors (squalene, 2,3-oxidosqualene) in only one enzymatic step that is catalyzed by squalene-hopene cyclase (shc) or oxidosqualene cyclase (osc). shcs and oscs are related in amino acid sequences and probably are derived from a common ancestor. the shc reaction requires the formation of ...201121531832
detection and isolation of chloromethane-degrading bacteria from the arabidopsis thaliana phyllosphere, and characterization of chloromethane utilization genes.chloromethane gas is produced naturally in the phyllosphere, the compartment defined as the aboveground parts of vegetation, which hosts a rich bacterial flora. chloromethane may serve as a growth substrate for specialized aerobic methylotrophic bacteria, which have been isolated from soil and water environments, and use cmu genes for chloromethane utilization. evidence for the presence of chloromethane-degrading bacteria on the leaf surfaces of arabidopsis thaliana was obtained by specific quan ...201121545604
direct measurement of oxygen consumption rates from attached and unattached cells in a reversibly sealed, diffusionally isolated sample chamber.oxygen consumption is a fundamental component of metabolic networks, mitochondrial function, and global carbon cycling. to date there is no method available that allows for replicate measurements on attached and unattached biological samples without compensation for extraneous oxygen leaking into the system. here we present the respiratory detection system, which is compatible with virtually any biological sample. the rds can be used to measure oxygen uptake in microliter-scale volumes with a re ...201021546993
genomic insights into the physiology and ecology of the marine filamentous cyanobacterium lyngbya majuscula.filamentous cyanobacteria of the genus lyngbya are important contributors to coral reef ecosystems, occasionally forming dominant cover and impacting the health of many other co-occurring organisms. moreover, they are extraordinarily rich sources of bioactive secondary metabolites, with 35% of all reported cyanobacterial natural products deriving from this single pantropical genus. however, the true natural product potential and life strategies of lyngbya strains are poorly understood because of ...201121555588
loss of allostery and coenzyme b(12) delivery by a pathogenic mutation in adenosyltransferase.atp-dependent cob(i)alamin adenosyltransferase (atr) is a bifunctional protein: an enzyme that catalyzes the adenosylation of cob(i)alamin and an escort that delivers the product, adenosylcobalamin (adocbl or coenzyme b(12)), to methylmalonyl-coa mutase (mcm), resulting in holoenzyme formation. failure to assemble holo-mcm leads to methylmalonic aciduria. we have previously demonstrated that only 2 equiv of adocbl bind per homotrimer of atr and that binding of atp to the vacant active site trigg ...201121604717
genomes of three methylotrophs from a single niche uncover genetic and metabolic divergence of methylophilaceae.the genomes of three representatives of the family methylophilaceae, methylotenera mobilis jlw8, methylotenera versatilis 301 and methylovorus glucosetrophus sip3-4, all isolated from a single study site, lake washington in seattle, were completely sequenced. these were compared to each other and to the previously published genomes of methylobacillus flagellatus kt and an unclassified methylophilales strain htcc2181. comparative analysis revealed that the core genome of methylophilaceae may be a ...201121622745
diminishing returns epistasis among beneficial mutations decelerates adaptation.epistasis has substantial impacts on evolution, in particular, the rate of adaptation. we generated combinations of beneficial mutations that arose in a lineage during rapid adaptation of a bacterium whose growth depended on a newly introduced metabolic pathway. the proportional selective benefit for three of the four loci consistently decreased when they were introduced onto more fit backgrounds. these three alleles all reduced morphological defects caused by expression of the foreign pathway. ...201121636771
introducing a new bioengineered bug: methylobacterium extorquens tuned as a microbial bioplastic factory.discussion on and use of methanol as chemical feedstock and as alternative fuel has gained momentum during the past years. consequently, microorganism and product design based on ''methylotrophism'' is in vogue as reflected by increasing research and development activities in methanol-related areas. a recent example of microorganism and product development is the use of recombinant methylobacterium extorquens atcc 55366 strains in the production of second generation biopolyesters. feeding n-alke ...201121636993
detection of dichloromethane with a bioluminescent (lux) bacterial bioreporter.the focus of this research effort was to develop an autonomous, inducible, lux-based bioluminescent bioreporter for the real-time detection of dichloromethane. dichloromethane (dcm), also known as methylene chloride, is a volatile organic compound and one of the most commonly used halogenated solvents in the u.s., with applications ranging from grease and paint stripping to aerosol propellants and pharmaceutical tablet coatings. predictably, it is released into the environment where it contamina ...201121688172
systems biology of the qa gene cluster in neurospora crassa.an ensemble of genetic networks that describe how the model fungal system, neurospora crassa, utilizes quinic acid (qa) as a sole carbon source has been identified previously. a genetic network for qa metabolism involves the genes, qa-1f and qa-1s, that encode a transcriptional activator and repressor, respectively and structural genes, qa-2, qa-3, qa-4, qa-x, and qa-y. by a series of 4 separate and independent, model-guided, microarray experiments a total of 50 genes are identified as qa-respon ...201121695121
Biochemical and Mutational Studies of the Bacillus cereus CECT 5050T Formamidase Support the Existence of a C-E-E-K Tetrad in Several Members of the Nitrilase Superfamily.Formamidases (EC 3.5.1.49) are poorly characterized proteins. In spite of this scarce knowledge, ammonia has been described as playing a central role in the pathogenesis of human pathogens such as Helicobacter pylori, for which formamidase has been shown to participate in the nitrogen metabolic pathway. Sequence analysis has revealed that at least two different groups of formamidases are classified as EC 3.5.1.49: on the one hand, the derivatives of the FmdA-AmdA superfamily, which are the best ...201121705545
type ivb secretion systems of legionella and other gram-negative bacteria.type iv secretion systems (t4sss) play a central role in the pathogenicity of many important pathogens, including agrobacterium tumefaciens, helicobacter pylori, and legionella pneumophila. the t4sss are related to bacterial conjugation systems, and are classified into two subgroups, type iva (t4ass) and type ivb (t4bss). the t4bss, which is closely related to conjugation systems of inci plasmids, was originally found in human pathogen l. pneumophila; pathogenesis by l. pneumophila infection req ...201121743810
effects of elevated atmospheric co(2) on rhizosphere soil microbial communities in a mojave desert ecosystem.the effects of elevated atmospheric carbon dioxide [co(2)] on microbial communities in arid rhizosphere soils beneath larrea tridentata were examined. roots of larrea were harvested from plots fumigated with elevated or ambient levels of [co(2)] using free-air co(2) enrichment (face) technology. twelve bacterial and fungal rrna gene libraries were constructed, sequenced and categorized into operational taxonomical units (otus). there was a significant decrease in otus within the firmicutes (bact ...201121779135
pole age affects cell size and the timing of cell division in methylobacterium extorquens am1.a number of recent experiments at the single-cell level have shown that genetically identical bacteria that live in homogeneous environments often show a substantial degree of phenotypic variation between cells. often, this variation is attributed to stochastic aspects of biology - the fact that many biological processes involve small numbers of molecules, and are thus inherently variable. however, not all variation between cells needs to be stochastic in nature; one deterministic process that c ...201121784923
genome and characterization of phages bcep22 and bcepil02, founders of a novel phage type in burkholderia cenocepacia.within the burkholderia cepacia complex (bcc), b. cenocepacia is the most common species associated with aggressive infections in the lungs of cystic fibrosis patients, causing disease that is often refractive to treatment by antibiotics. phage therapy may be a potential alternative form of treatment for these infections. here we describe the genome of the previously described therapeutic b. cenocepacia podophage bcepil02 and its close relative, bcep22. phage bcep22 was found to contain a circul ...201121804006
the mosaicism of plasmids revealed by atypical genes detection and analysis.from an evolutionary viewpoint, prokaryotic genomes are extremely plastic and dynamic, since large amounts of genetic material are continuously added and/or lost through promiscuous gene exchange. in this picture, plasmids play a key role, since they can be transferred between different cells and, through genetic rearrangement(s), undergo gene(s) load, leading, in turn, to the appearance of important metabolic innovations that might be relevant for cell life. despite their central position in ba ...201121824433
transport genes and chemotaxis in laribacter hongkongensis: a genome-wide analysis.abstract:201121849034
functional genomics of dichloromethane utilization in methylobacterium extorquens dm4.dichloromethane (ch(2)cl(2) , dcm) is a chlorinated solvent mainly produced by industry, and a common pollutant. some aerobic methylotrophic bacteria are able to grow with this chlorinated methane as their sole carbon and energy source, using a dcm dehalogenase/glutathione s-transferase encoded by dcma to transform dcm into two molecules of hcl and one molecule of formaldehyde, a toxic intermediate of methylotrophic metabolism. in methylobacterium extorquens dm4 of known genome sequence, dcma li ...201121854516
carbon metabolic pathways in phototrophic bacteria and their broader evolutionary implications.photosynthesis is the biological process that converts solar energy to biomass, bio-products, and biofuel. it is the only major natural solar energy storage mechanism on earth. to satisfy the increased demand for sustainable energy sources and identify the mechanism of photosynthetic carbon assimilation, which is one of the bottlenecks in photosynthesis, it is essential to understand the process of solar energy storage and associated carbon metabolism in photosynthetic organisms. researchers hav ...201121866228
complete genome sequence of the chloromethane-degrading hyphomicrobium sp. strain mc1.hyphomicrobium sp. strain mc1 is an aerobic methylotroph originally isolated from industrial sewage. this prosthecate bacterium was the first strain reported to grow with chloromethane as the sole carbon and energy source. its genome, consisting of a single 4.76-mb chromosome, is the first for a chloromethane-degrading bacterium to be formally reported.201121868803
XoxF is required for expression of methanol dehydrogenase in Methylobacterium extorquens AM1.In Gram-negative methylotrophic bacteria, the first step in methylotrophic growth is the oxidation of methanol to formaldehyde in the periplasm by methanol dehydrogenase. In most organisms studied to date, this enzyme consists of the MxaF and MxaI proteins, which make up the large and small subunits of this heterotetrameric enzyme. The Methylobacterium extorquens AM1 genome contains two homologs of MxaF, XoxF1 and XoxF2, which are ~50% identical to MxaF and ~90% identical to each other. It was p ...201121873495
one carbon metabolism in sar11 pelagic marine bacteria.the sar11 alphaproteobacteria are the most abundant heterotrophs in the oceans and are believed to play a major role in mineralizing marine dissolved organic carbon. their genomes are among the smallest known for free-living heterotrophic cells, raising questions about how they successfully utilize complex organic matter with a limited metabolic repertoire. here we show that conserved genes in sar11 subgroup ia (candidatus pelagibacter ubique) genomes encode pathways for the oxidation of a varie ...201121886845
mdor is a novel positive transcriptional regulator for the oxidation of methanol in mycobacterium sp. strain jc1.mycobacterium sp. strain jc1 is able to grow on methanol as a sole source of carbon and energy using methanol:n,n'-dimethyl-4-nitrosoaniline oxidoreductase (mdo) as a key enzyme for methanol oxidation. the second open reading frame (mdor) upstream of, and running divergently from, the mdo gene was identified as a gene for a tetr family transcriptional regulator. the n-terminal region of mdor contained a helix-turn-helix dna-binding motif. an electrophoretic mobility shift assay (emsa) indicated ...201121908665
role of sphingomonas sp. strain fr1 phyr-nepr-σecfg cascade in general stress response and identification of a negative regulator of phyr.the general stress response in alphaproteobacteria was recently described to depend on the alternative sigma factor σ(ecfg), whose activity is regulated by its anti-sigma factor nepr. the response regulator phyr, in turn, regulates nepr activity in a partner-switching mechanism according to which phosphorylation of phyr triggers sequestration of nepr by the sigma factor-like effector domain of phyr. although genes encoding predicted histidine kinases can often be found associated with phyr, litt ...201121949070
Isovaleryl-homoserine lactone, an unusual branched-chain quorum-sensing signal from the soybean symbiont Bradyrhizobium japonicum.Many species of Proteobacteria communicate by using LuxI-LuxR-type quorum-sensing systems that produce and detect acyl-homoserine lactone (acyl-HSL) signals. Most of the known signals are straight-chain fatty acyl-HSLs, and evidence indicates that LuxI homologs prefer fatty acid-acyl carrier protein (ACP) over fatty acyl-CoA as the acyl substrate for signal synthesis. Two related LuxI homologs, RpaI and BtaI from Rhodopseudomonas palustris and photosynthetic stem-nodulating bradyrhizobia, direct ...201121949379
sequence variability of rhizobiales orthologs and relationship with physico-chemical characteristics of proteins.chromosomal orthologs can reveal the shared ancestral gene set and their evolutionary trends. additionally, physico-chemical properties of encoded proteins could provide information about functional adaptation and ecological niche requirements.201121970442
the causes of epistasis.since bateson's discovery that genes can suppress the phenotypic effects of other genes, gene interactions-called epistasis-have been the topic of a vast research effort. systems and developmental biologists study epistasis to understand the genotype-phenotype map, whereas evolutionary biologists recognize the fundamental importance of epistasis for evolution. depending on its form, epistasis may lead to divergence and speciation, provide evolutionary benefits to sex and affect the robustness an ...201121976687
carboxylases in natural and synthetic microbial pathways.carboxylases are among the most important enzymes in the biosphere, because they catalyze a key reaction in the global carbon cycle: the fixation of inorganic carbon (co₂). this minireview discusses the physiological roles of carboxylases in different microbial pathways that range from autotrophy, carbon assimilation, and anaplerosis to biosynthetic and redox-balancing functions. in addition, the current and possible future uses of carboxylation reactions in synthetic biology are discussed. such ...201122003013
Microbial degradation of furanic compounds: biochemistry, genetics, and impact.Microbial metabolism of furanic compounds, especially furfural and 5-hydroxymethylfurfural (HMF), is rapidly gaining interest in the scientific community. This interest can largely be attributed to the occurrence of toxic furanic aldehydes in lignocellulosic hydrolysates. However, these compounds are also widespread in nature and in human processed foods, and are produced in industry. Although several microorganisms are known to degrade furanic compounds, the variety of species is limited mostly ...201122031465
genome-scale reconstruction and system level investigation of the metabolic network of methylobacterium extorquens am1.methylotrophic microorganisms are playing a key role in biogeochemical processes - especially the global carbon cycle - and have gained interest for biotechnological purposes. significant progress was made in the recent years in the biochemistry, genetics, genomics, and physiology of methylotrophic bacteria, showing that methylotrophy is much more widespread and versatile than initially assumed. despite such progress, system-level description of the methylotrophic metabolism is currently lacking ...201122074569
The Ethylmalonyl-CoA Pathway Is Used in Place of the Glyoxylate Cycle by Methylobacterium extorquens AM1 during Growth on Acetate.Acetyl-CoA assimilation was extensively studied in organisms harboring the glyoxylate cycle. In this study, we analyzed the metabolism of the facultative methylotroph Methylobacterium extorquens AM1, which lacks isocitrate lyase, the key enzyme in the glyoxylate cycle, during growth on acetate. MS/MS-based proteomic analysis revealed that the protein repertoire of M. extorquens AM1 grown on acetate is similar to that of cells grown on methanol and includes enzymes of the ethylmalonyl-CoA (EMC) p ...201222105076
Phylogenomics of Reichenowia parasitica, an Alphaproteobacterial Endosymbiont of the Freshwater Leech Placobdella parasitica.Although several commensal alphaproteobacteria form close relationships with plant hosts where they aid in (e.g.,) nitrogen fixation and nodulation, only a few inhabit animal hosts. Among these, Reichenowia picta, R. ornata and R. parasitica, are currently the only known mutualistic, alphaproteobacterial endosymbionts to inhabit leeches. These bacteria are harbored in the epithelial cells of the mycetomal structures of their freshwater leech hosts, Placobdella spp., and these structures have no ...201122132238
Diversity of Five Anaerobic Toluene Degrading Microbial Communities Investigated using Stable Isotope Probing (SIP).Time-series DNA-stable isotope probing (SIP) was used to identify the microbes assimilating carbon from (13)C-toluene under nitrate or sulfate amended conditions in a range of inoculum sources, including uncontaminated and contaminated soil and wastewater treatment samples. In all, five different phylotypes were found to be responsible for toluene degradation and these included previously identified toluene degraders as well as novel toluene degrading microorganisms. In microcosms inoculated fro ...201122156434
Genomes and Virulence Factors of Novel Bacterial Pathogens Causing Bleaching Disease in the Marine Red Alga Delisea pulchra.Nautella sp. R11, a member of the marine Roseobacter clade, causes a bleaching disease in the temperate-marine red macroalga, Delisea pulchra. To begin to elucidate the molecular mechanisms underpinning the ability of Nautella sp. R11 to colonize, invade and induce bleaching of D. pulchra, we sequenced and analyzed its genome. The genome encodes several factors such as adhesion mechanisms, systems for the transport of algal metabolites, enzymes that confer resistance to oxidative stress, cytolys ...201122162749
novel coenzyme b12-dependent interconversion of isovaleryl-coa and pivalyl-coa.5'-deoxyadenosylcobalamin (adocbl)-dependent isomerases catalyze carbon skeleton rearrangements using radical chemistry. we have recently characterized a fusion protein that comprises the two subunits of the adocbl-dependent isobutyryl-coa mutase flanking a g-protein chaperone and named it isobutyryl-coa mutase fused (icmf). icmf catalyzes the interconversion of isobutyryl-coa and n-butyryl-coa, whereas gtpase activity is associated with its g-protein domain. in this study, we report a novel act ...201122167181
novel coenzyme b12-dependent interconversion of isovaleryl-coa and pivalyl-coa.5'-deoxyadenosylcobalamin (adocbl)-dependent isomerases catalyze carbon skeleton rearrangements using radical chemistry. we have recently characterized a fusion protein that comprises the two subunits of the adocbl-dependent isobutyryl-coa mutase flanking a g-protein chaperone and named it isobutyryl-coa mutase fused (icmf). icmf catalyzes the interconversion of isobutyryl-coa and n-butyryl-coa, whereas gtpase activity is associated with its g-protein domain. in this study, we report a novel act ...201122167181
widespread genetic switches and toxicity resistance proteins for fluoride.most riboswitches are metabolite-binding rna structures located in bacterial messenger rnas where they control gene expression. we have discovered a riboswitch class in many bacterial and archaeal species whose members are selectively triggered by fluoride but reject other small anions, including chloride. these fluoride riboswitches activate expression of genes that encode putative fluoride transporters, enzymes that are known to be inhibited by fluoride, and additional proteins of unknown func ...201122194412
widespread genetic switches and toxicity resistance proteins for fluoride.most riboswitches are metabolite-binding rna structures located in bacterial messenger rnas where they control gene expression. we have discovered a riboswitch class in many bacterial and archaeal species whose members are selectively triggered by fluoride but reject other small anions, including chloride. these fluoride riboswitches activate expression of genes that encode putative fluoride transporters, enzymes that are known to be inhibited by fluoride, and additional proteins of unknown func ...201122194412
identification and characterization of rhodopseudomonas palustris tie-1 hopanoid biosynthesis mutants.hopanes preserved in both modern and ancient sediments are recognized as the molecular fossils of bacteriohopanepolyols, pentacyclic hopanoid lipids. based on the phylogenetic distribution of hopanoid production by extant bacteria, hopanes have been used as indicators of specific bacterial groups and/or their metabolisms. however, our ability to interpret them ultimately depends on understanding the physiological roles of hopanoids in modern bacteria. toward this end, we set out to identify gene ...201222221333
architectural design influences the diversity and structure of the built environment microbiome.buildings are complex ecosystems that house trillions of microorganisms interacting with each other, with humans and with their environment. understanding the ecological and evolutionary processes that determine the diversity and composition of the built environment microbiome--the community of microorganisms that live indoors--is important for understanding the relationship between building design, biodiversity and human health. in this study, we used high-throughput sequencing of the bacterial ...201222278670
distribution and properties of the genes encoding the biosynthesis of the bacterial cofactor, pyrroloquinoline quinone.pyrroloquinoline quinone (pqq) is a small, redox active molecule that serves as a cofactor for several bacterial dehydrogenases, introducing pathways for carbon utilization that confer a growth advantage. early studies had implicated a ribosomally translated peptide as the substrate for pqq production. this study presents a sequence- and structure-based analysis of the components of the pqq operon. we find the necessary components for pqq production are present in 126 prokaryotes, most of which ...201222324760
the abundance of pink-pigmented facultative methylotrophs in the root zone of plant species in invaded coastal sage scrub habitat.pink-pigmented facultative methylotrophic bacteria (ppfms) are associated with the roots, leaves and seeds of most terrestrial plants and utilize volatile c(1) compounds such as methanol generated by growing plants during cell division. ppfms have been well studied in agricultural systems due to their importance in crop seed germination, yield, pathogen resistance and drought stress tolerance. in contrast, little is known about the ppfm abundance and diversity in natural ecosystems, let alone th ...201222383990
working together for the common good: cell-cell communication in bacteria.the 4th asm conference on cell-cell communication in bacteria was held in miami, fl, from 6 to 9 november 2011. this review highlights three key themes that emerged from the many exciting talks and poster presentations in the area of quorum sensing: sociomicrobiology, signal transduction mechanisms, and interspecies communication.201222389476
[3' flanking region analysis of the dichloromethane dehalogenase gene of dcma methylobacterium dichloromethanicum dm4]. 201122393764
the lovk-lovr two-component system is a regulator of the general stress pathway in caulobacter crescentus.a conserved set of regulators control the general stress response in caulobacter crescentus, including σ(t), its anti-σ factor nepr, the anti-anti-σ factor phyr, and the transmembrane sensor kinase phyk. we report that the soluble histidine kinase lovk and the single-domain response regulator lovr also function within the c. crescentus general stress pathway. our genetic data support a model in which lovk-lovr functions upstream of σ(t) by controlling the phosphorylation state and thus anti-anti ...201222408156
ccrr, a tetr family transcriptional regulator, activates the transcription of a gene of the ethylmalonyl coenzyme a pathway in methylobacterium extorquens am1.the ethylmalonyl coenzyme a (ethylmalonyl-coa) pathway is one of the central methylotrophy pathways in methylobacterium extorquens involved in glyoxylate generation and acetyl-coa assimilation. previous studies have elucidated the operation of the ethylmalonyl-coa pathway in c(1) and c(2) assimilation, but the regulatory mechanisms for the ethylmalonyl-coa pathway have not been reported. in this study, a tetr-type activator, ccrr, was shown to regulate the expression of crotonyl-coa reductase/ca ...201222447902
the effect of nitrogen enrichment on c(1)-cycling microorganisms and methane flux in salt marsh sediments.methane (ch(4)) flux from ecosystems is driven by c(1)-cycling microorganisms - the methanogens and the methylotrophs. little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. using a nitrogen addition gradient experiment in three southern california salt marshes, we show that sediment ch(4) flux increased linearly with increasing nitrogen addition (1.23 μg ch(4) m(-2) day(-1) fo ...201222470369
practical application of methanol-mediated mutualistic symbiosis between methylobacterium species and a roof greening moss, racomitrium japonicum.bryophytes, or mosses, are considered the most maintenance-free materials for roof greening. racomitrium species are most often used due to their high tolerance to desiccation. because they grow slowly, a technology for forcing their growth is desired. we succeeded in the efficient production of r. japonicum in liquid culture. the structure of the microbial community is crucial to stabilize the culture. a culture-independent technique revealed that the cultures contain methylotrophic bacteria. u ...201222479445
analysis of 16s rrna and mxaf genes revealing insights into methylobacterium niche-specific plant association.the genus methylobacterium comprises pink-pigmented facultative methylotrophic (ppfm) bacteria, known to be an important plant-associated bacterial group. species of this group, described as plant-nodulating, have the dual capacity of producing cytokinin and enzymes, such as pectinase and cellulase, involved in systemic resistance induction and nitrogen fixation under specific plant environmental conditions. the aim hereby was to evaluate the phylogenetic distribution of methylobacterium spp. is ...201222481887
oxalyl-coenzyme a reduction to glyoxylate is the preferred route of oxalate assimilation in methylobacterium extorquens am1.oxalate catabolism is conducted by phylogenetically diverse organisms, including methylobacterium extorquens am1. here, we investigate the central metabolism of this alphaproteobacterium during growth on oxalate by using proteomics, mutant characterization, and (13)c-labeling experiments. our results confirm that energy conservation proceeds as previously described for m. extorquens am1 and other characterized oxalotrophic bacteria via oxalyl-coenzyme a (oxalyl-coa) decarboxylase and formyl-coa ...201222493020
gas chromatography-mass spectrometry with chemometric analysis for determining ¹²c and ¹³c labeled contributions in metabolomics and ¹³c flux analysis.a novel method for the analysis of nearly co-eluting ¹²c and ¹³c isotopically labeled metabolites has been developed and evaluated for gas chromatography coupled to mass spectrometry (gc-ms) data. the method utilizes parallel factor analysis (parafac) with two-dimensional gc-ms data when sample replicates are aligned and stacked in series to create a three-dimensional data cube for mathematical peak deconvolution and ¹²c and ¹³c contribution isolation, with the intent of increasing the accuracy ...201222503618
structural basis for sigma factor mimicry in the general stress response of alphaproteobacteria.reprogramming gene expression is an essential component of adaptation to changing environmental conditions. in bacteria, a widespread mechanism involves alternative sigma factors that redirect transcription toward specific regulons. the activity of sigma factors is often regulated through sequestration by cognate anti-sigma factors; however, for most systems, it is not known how the activity of the anti-sigma factor is controlled to release the sigma factor. recently, the general stress response ...201222550171
structural basis of a protein partner switch that regulates the general stress response of α-proteobacteria.α-proteobacteria uniquely integrate features of two-component signal transduction (tcs) and alternative sigma factor (σ) regulation to control transcription in response to general stress. the core of this regulatory system is the phyr protein, which contains a σ-like (sl) domain and a tcs receiver domain. aspartyl phosphorylation of the phyr receiver in response to stress signals promotes binding of the anti-σ factor, nepr, to phyr-sl. this mechanism, whereby nepr switches binding between its co ...201222550172
investigation of the role of arg301 identified in the x-ray structure of phosphite dehydrogenase.phosphite dehydrogenase (ptdh) from pseudomonas stutzeri catalyzes the nicotinamide adenine dinucleotide-dependent oxidation of phosphite to phosphate. the enzyme belongs to the family of d-hydroxy acid dehydrogenases (dhdhs). a search of the protein databases uncovered many additional putative phosphite dehydrogenases. the genes encoding four diverse candidates were cloned and expressed, and the enzymes were purified and characterized. all oxidized phosphite to phosphate and had similar kinetic ...201222564138
repeated, selection-driven genome reduction of accessory genes in experimental populations.genome reduction has been observed in many bacterial lineages that have adapted to specialized environments. the extreme genome degradation seen for obligate pathogens and symbionts appears to be dominated by genetic drift. in contrast, for free-living organisms with reduced genomes, the dominant force is proposed to be direct selection for smaller, streamlined genomes. most variation in gene content for these free-living species is of "accessory" genes, which are commonly gained as large chromo ...201222589730
genome sequence of thermotolerant bacillus methanolicus: features and regulation related to methylotrophy and production of l-lysine and l-glutamate from methanol.bacillus methanolicus can utilize methanol as its sole carbon and energy source, and the scientific interest in this thermotolerant bacterium has focused largely on exploring its potential as a biocatalyst for the conversion of methanol into l-lysine and l-glutamate. we present here the genome sequences of the important b. methanolicus model strain mga3 (atcc 53907) and the alternative wild-type strain pb1 (ncimb13113). the physiological diversity of these two strains was demonstrated by a compa ...201222610424
computational tools for metabolic engineering.a great variety of software applications are now employed in the metabolic engineering field. these applications have been created to support a wide range of experimental and analysis techniques. computational tools are utilized throughout the metabolic engineering workflow to extract and interpret relevant information from large data sets, to present complex models in a more manageable form, and to propose efficient network design strategies. in this review, we present a number of tools that ca ...201222629572
role of vitamin b12 on methylmalonyl-coa mutase activity.vitamin b(12) is an organometallic compound with important metabolic derivatives that act as cofactors of certain enzymes, which have been grouped into three subfamilies depending on their cofactors. among them, methylmalonyl-coa mutase (mcm) has been extensively studied. this enzyme catalyzes the reversible isomerization of l-methylmalonyl-coa to succinyl-coa using adenosylcobalamin (adocbl) as a cofactor participating in the generation of radicals that allow isomerization of the substrate. the ...201222661206
epimerase (msed_0639) and mutase (msed_0638 and msed_2055) convert (s)-methylmalonyl-coenzyme a (coa) to succinyl-coa in the metallosphaera sedula 3-hydroxypropionate/4-hydroxybutyrate cycle.crenarchaeotal genomes encode the 3-hydroxypropionate/4-hydroxybutyrate (3-hp/4-hb) cycle for carbon dioxide fixation. of the 13 enzymes putatively comprising the cycle, several of them, including methylmalonyl-coenzyme a (coa) epimerase (mce) and methylmalonyl-coa mutase (mcm), which convert (s)-methylmalonyl-coa to succinyl-coa, have not been confirmed and characterized biochemically. in the genome of metallosphaera sedula (optimal temperature [t(opt)], 73°c), the gene encoding mce (msed_0639) ...201222752162
recovering from a bad start: rapid adaptation and tradeoffs to growth below a threshold density.bacterial growth in well-mixed culture is often assumed to be an autonomous process only depending upon the external conditions under control of the investigator. however, increasingly there is awareness that interactions between cells in culture can lead to surprising phenomena such as density-dependence in the initiation of growth.201222762241
structure-guided expansion of the substrate range of methylmalonyl coenzyme a synthetase (matb) of rhodopseudomonas palustris.malonyl coenzyme a (malonyl-coa) and methylmalonyl-coa are two of the most commonly used extender units for polyketide biosynthesis and are utilized to synthesize a vast array of pharmaceutically relevant products with antibacterial, antiparasitic, anticholesterol, anticancer, antifungal, and immunosuppressive properties. heterologous hosts used for polyketide production such as escherichia coli often do not produce significant amounts of methylmalonyl-coa, however, requiring the introduction of ...201222773649
novel b(12)-dependent acyl-coa mutases and their biotechnological potential.the recent spate of discoveries of novel acyl-coa mutases has engendered a growing appreciation for the diversity of 5'-deoxyadenosylcobalamin-dependent rearrangement reactions. the prototype of the reaction catalyzed by these enzymes is the 1,2 interchange of a hydrogen atom with a thioester group leading to a change in the degree of carbon skeleton branching. these enzymes are predicted to share common architectural elements: a rossman fold and a triose phosphate isomerase (tim)-barrel domain ...201222803641
endophytic methylobacterium extorquens expresses a heterologous β-1,4-endoglucanase a (egla) in catharanthus roseus seedlings, a model host plant for xylella fastidiosa.based on the premise of symbiotic control, we genetically modified the citrus endophytic bacterium methylobacterium extorquens, strain ar1.6/2, and evaluated its capacity to colonize a model plant and its interaction with xylella fastidiosa, the causative agent of citrus variegated chlorosis (cvc). ar1.6/2 was genetically transformed to express heterologous gfp (green fluorescent protein) and an endoglucanase a (egla), generating the strains argfp and aregla, respectively. by fluorescence micros ...201122805929
identification of a novel calcium binding motif based on the detection of sequence insertions in the animal peroxidase domain of bacterial proteins.proteins of the animal heme peroxidase (anp) superfamily differ greatly in size since they have either one or two catalytic domains that match profile ps50292. the orf pp_2561 of pseudomonas putida kt2440 that we have called pepa encodes a two-domain anp. the alignment of these domains with those of pepa homologues revealed a variable number of insertions with the consensus g-x-d-g-x-x-[gn]-[tn]-x-d-d. this motif has also been detected in the structure of pseudopilin (pdb 3g20), where it was fou ...201222808235
structure and function of biotin-dependent carboxylases.biotin-dependent carboxylases include acetyl-coa carboxylase (acc), propionyl-coa carboxylase (pcc), 3-methylcrotonyl-coa carboxylase (mcc), geranyl-coa carboxylase, pyruvate carboxylase (pc), and urea carboxylase (uc). they contain biotin carboxylase (bc), carboxyltransferase (ct), and biotin-carboxyl carrier protein components. these enzymes are widely distributed in nature and have important functions in fatty acid metabolism, amino acid metabolism, carbohydrate metabolism, polyketide biosynt ...201222869039
structure and function of biotin-dependent carboxylases.biotin-dependent carboxylases include acetyl-coa carboxylase (acc), propionyl-coa carboxylase (pcc), 3-methylcrotonyl-coa carboxylase (mcc), geranyl-coa carboxylase, pyruvate carboxylase (pc), and urea carboxylase (uc). they contain biotin carboxylase (bc), carboxyltransferase (ct), and biotin-carboxyl carrier protein components. these enzymes are widely distributed in nature and have important functions in fatty acid metabolism, amino acid metabolism, carbohydrate metabolism, polyketide biosynt ...201222869039
revelation of the ability of burkholderia sp. usm (jcm 15050) pha synthase to polymerize 4-hydroxybutyrate monomer.the nutrition-versatility of burkholderia sp. strain usm (jcm 15050) has initiated the studies on the use of this bacterium for polyhydroxyalkanoate (pha) production. to date, the burkholderia sp. has been reported to synthesize 3-hydroxybutyrate, 3-hydroxyvalerate and 3-hydroxy-4-methylvalerate monomers. in this study, the pha biosynthetic genes of this strain were successfully cloned and characterized. the pha biosynthetic cluster of this strain consisted of a pha synthase (phac), β-ketothiola ...201222877240
recent advances in mapping environmental microbial metabolisms through 13c isotopic fingerprints.after feeding microbes with a defined (13)c substrate, unique isotopic patterns (isotopic fingerprints) can be formed in their metabolic products. such labelling information not only can provide novel insights into functional pathways but also can determine absolute carbon fluxes through the metabolic network via metabolic modelling approaches. this technique has been used for finding pathways that may have been mis-annotated in the past, elucidating new enzyme functions, and investigating cell ...201222896564
epistasis from functional dependence of fitness on underlying traits.epistasis between mutations in two genes is thought to reflect an interdependence of their functions. while sometimes epistasis is predictable using mechanistic models, its roots seem, in general, hidden in the complex architecture of biological networks. here, we ask how epistasis can be quantified based on the mathematical dependence of a system-level trait (e.g. fitness) on lower-level traits (e.g. molecular or cellular properties). we first focus on a model in which fitness is the difference ...201222896647
oasis: an automated program for global investigation of bacterial and archaeal insertion sequences.insertion sequences (iss) are simple transposable elements present in most bacterial and archaeal genomes and play an important role in genomic evolution. the recent expansion of sequenced genomes offers the opportunity to study iss comprehensively, but this requires efficient and accurate tools for is annotation. we have developed an open-source program called oasis, or optimized annotation system for insertion sequences, which automatically annotates iss within sequenced genomes. oasis annotat ...201222904081
promoter propagation in prokaryotes.transcriptional activation or 'rewiring' of silent genes is an important, yet poorly understood, phenomenon in prokaryotic genomes. anecdotal evidence coming from experimental evolution studies in bacterial systems has shown the promptness of adaptation upon appropriate selective pressure. in many cases, a partial or complete promoter is mobilized to silent genes from elsewhere in the genome. we term hereafter such recruited regulatory sequences as putative mobile promoters (pmps) and we hypothe ...201222933716
genome sequence of methylobacterium sp. strain gxf4, a xylem-associated bacterium isolated from vitis vinifera l. grapevine.methylobacterium sp. strain gxf4 is an isolate from grapevine. here we present the sequence, assembly, and annotation of its genome, which may shed light on its role as a grapevine xylem inhabitant. to our knowledge, this is the first genome announcement of a plant xylem-associated strain of the genus methylobacterium.201222933776
copper starvation-inducible protein for cytochrome oxidase biogenesis in bradyrhizobium japonicum.microarray analysis of bradyrhizobium japonicum grown under copper limitation uncovered five genes named pcuabcde, which are co-transcribed and co-regulated as an operon. the predicted gene products are periplasmic proteins (pcua, pcuc, and pcud), a tonb-dependent outer membrane receptor (pcub), and a cytoplasmic membrane-integral protein (pcue). homologs of pcuc and pcue had been discovered in other bacteria, namely pcu(a)c and ycnj, where they play a role in cytochrome oxidase biogenesis and c ...201223012364
bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. this may be potentially useful for bioaugmentation and microbial enhanced oil recovery (meor). however, it is not entirely clear if "endogenous" bacteria (e.g., spores) in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. to test this, we inoculated autoclaved crude oil medium with six exo ...201223028421
clarity: an open-source manager for laboratory automation.software to manage automated laboratories, when interfaced with hardware instruments, gives users a way to specify experimental protocols and schedule activities to avoid hardware conflicts. in addition to these basics, modern laboratories need software that can run multiple different protocols in parallel and that can be easily extended to interface with a constantly growing diversity of techniques and instruments. we present clarity, a laboratory automation manager that is hardware agnostic, p ...201223032169
clarity: an open-source manager for laboratory automation.software to manage automated laboratories, when interfaced with hardware instruments, gives users a way to specify experimental protocols and schedule activities to avoid hardware conflicts. in addition to these basics, modern laboratories need software that can run multiple different protocols in parallel and that can be easily extended to interface with a constantly growing diversity of techniques and instruments. we present clarity, a laboratory automation manager that is hardware agnostic, p ...201223032169
complete genome sequence and metabolic potential of the quinaldine-degrading bacterium arthrobacter sp. rue61a.bacteria of the genus arthrobacter are ubiquitous in soil environments and can be considered as true survivalists. arthrobacter sp. strain rue61a is an isolate from sewage sludge able to utilize quinaldine (2-methylquinoline) as sole carbon and energy source. the genome provides insight into the molecular basis of the versatility and robustness of this environmental arthrobacter strain.201223039946
methylobacterium-induced endophyte community changes correspond with protection of plants against pathogen attack.plant inoculation with endophytic bacteria that normally live inside the plant without harming the host is a highly promising approach for biological disease control. the mechanism of resistance induction by beneficial bacteria is poorly understood, because pathways are only partly known and systemic responses are typically not seen. the innate endophytic community structures change in response to external factors such as inoculation, and bacterial endophytes can exhibit direct or indirect antag ...201223056459
[functional analysis of the genome fragment involved in aerobic dichloromethane degradation by methylobacterium dichloromethanicum dm4].the hypothetical genes of methylobacterium dichloromethanicum dm4, metdi 2671 (biod2), and metdi 2680 located within the chromosomal fragment (126 kb) associated with dichloromethane (dcm) degradation have been studied. the reverse transcription polymerase chain reaction method (rt-pcr) showed the presence of transcripts of both genes in cells grown on dcm and methanol. the mobilized suicidal vector pk18mob was used to obtain knockout mutants in these genes. the bio mutant (with an insertion in ...201323101389
fim-1, a new acquired metallo-β-lactamase from a pseudomonas aeruginosa clinical isolate from italy.acquired metallo-β-lactamases (mbls) are resistance determinants of increasing clinical importance in gram-negative bacterial pathogens, which confer a broad-spectrum β-lactam resistance, including carbapenems. several such enzymes have been described since the 1990s. in the present study, a novel acquired mbl, named fim-1, was identified and characterized. the bla(fim-1) gene was cloned from a multidrug-resistant pseudomonas aeruginosa clinical isolate (fi-14/157) cultured from a patient with a ...201323114762
freq-seq: a rapid, cost-effective, sequencing-based method to determine allele frequencies directly from mixed populations.understanding evolutionary dynamics within microbial populations requires the ability to accurately follow allele frequencies through time. here we present a rapid, cost-effective method (freq-seq) that leverages illumina next-generation sequencing for localized, quantitative allele frequency detection. analogous to rna-seq, freq-seq relies upon counts from the >10(5) reads generated per locus per time-point to determine allele frequencies. loci of interest are directly amplified from a mixed po ...201223118913
co-consumption of methanol and succinate by methylobacterium extorquens am1.methylobacterium extorquens am1 is a facultative methylotrophic alphaproteobacterium and has been subject to intense study under pure methylotrophic as well as pure heterotrophic growth conditions in the past. here, we investigated the metabolism of m. extorquens am1 under mixed substrate conditions, i.e., in the presence of methanol plus succinate. we found that both substrates were co-consumed, and the carbon conversion was two-thirds from succinate and one-third from methanol relative to mol ...201223133625
adaptive evolution: evaluating empirical support for theoretical predictions.adaptive evolution is shaped by the interaction of population genetics, natural selection and underlying network and biochemical constraints. variation created by mutation, the raw material for evolutionary change, is translated into phenotypes by flux through metabolic pathways and by the topography and dynamics of molecular networks. finally, the retention of genetic variation and the efficacy of selection depend on population genetics and demographic history. emergent high-throughput experime ...201223154809
a catalytic role of xoxf1 as la3+-dependent methanol dehydrogenase in methylobacterium extorquens strain am1.in the methylotrophic bacterium methylobacterium extorquens strain am1, mxaf, a ca(2+)-dependent methanol dehydrogenase (mdh), is the main enzyme catalyzing methanol oxidation during growth on methanol. the genome of strain am1 contains another mdh gene homologue, xoxf1, whose function in methanol metabolism has remained unclear. in this work, we show that xoxf1 also functions as an mdh and is la(3+)-dependent. despite the absence of ca(2+) in the medium strain am1 was able to grow on methanol i ...201223209751
good codons, bad transcript: large reductions in gene expression and fitness arising from synonymous mutations in a key enzyme.biased codon usage in protein-coding genes is pervasive, whereby amino acids are largely encoded by a specific subset of possible codons. within individual genes, codon bias is stronger at evolutionarily conserved residues, favoring codons recognized by abundant trnas. although this observation suggests an overall pattern of selection for translation speed and/or accuracy, other work indicates that transcript structure or binding motifs drive codon usage. however, our understanding of codon bias ...201223223712
good codons, bad transcript: large reductions in gene expression and fitness arising from synonymous mutations in a key enzyme.biased codon usage in protein-coding genes is pervasive, whereby amino acids are largely encoded by a specific subset of possible codons. within individual genes, codon bias is stronger at evolutionarily conserved residues, favoring codons recognized by abundant trnas. although this observation suggests an overall pattern of selection for translation speed and/or accuracy, other work indicates that transcript structure or binding motifs drive codon usage. however, our understanding of codon bias ...201223223712
sinorhizobium meliloti sigma factors rpoe1 and rpoe4 are activated in stationary phase in response to sulfite.rhizobia are soil bacteria able to establish a nitrogen-fixing symbiosis with legume plants. both in soil and in planta, rhizobia spend non-growing periods resembling the stationary phase of in vitro-cultured bacteria. the primary objective of this work was to better characterize gene regulation in this biologically relevant growth stage in sinorhizobium meliloti. by a tap-tag/mass spectrometry approach, we identified five sigma factors co-purifying with the rna polymerase in stationary phase: t ...201223226379
methanol oxidation by temperate soils and environmental determinants of associated methylotrophs.the role of soil methylotrophs in methanol exchange with the atmosphere has been widely overlooked. methanol can be derived from plant polymers and be consumed by soil microbial communities. in the current study, methanol-utilizing methylotrophs of 14 aerated soils were examined to resolve their comparative diversities and capacities to utilize ambient concentrations of methanol. abundances of cultivable methylotrophs ranged from 10(6)-10(8) gsoildw(-1). methanol dissimilation was measured based ...201223254514
methanol oxidation by temperate soils and environmental determinants of associated methylotrophs.the role of soil methylotrophs in methanol exchange with the atmosphere has been widely overlooked. methanol can be derived from plant polymers and be consumed by soil microbial communities. in the current study, methanol-utilizing methylotrophs of 14 aerated soils were examined to resolve their comparative diversities and capacities to utilize ambient concentrations of methanol. abundances of cultivable methylotrophs ranged from 10(6)-10(8) gsoildw(-1). methanol dissimilation was measured based ...201223254514
metagenomic profiles of free-living archaea, bacteria and small eukaryotes in coastal areas of sichang island, thailand.tha wang and tham phang coasts, though situated at similar oceanographic positions on sichang island, chonburi province, thailand, are different in bay geography and amount of municipal disturbances. these affect the marine ecosystems. the study used metagenomics combined with 16s and 18s rdna pyrosequencing to identify types and distributions of archaea, bacteria, fungi and small eukaryotes of sizes ranges 0.45 and ~30 μm.201223282134
synchronous waves of failed soft sweeps in the laboratory: remarkably rampant clonal interference of alleles at a single locus.it has increasingly been recognized that adapting populations of microbes contain not one, but many lineages continually arising and competing at once. this process, termed "clonal interference," alters the rate and dynamics of adaptation and biases winning mutations toward those with the largest selective effect. here we uncovered a dramatic example of clonal interference between multiple similar mutations occurring at the same locus within replicate populations of methylobacterium extorquens a ...201323307898
distribution and origin of oxygen-dependent and oxygen-independent forms of mg-protoporphyrin monomethylester cyclase among phototrophic proteobacteria.magnesium-protoporphyrin ix monomethylester cyclase is one of the key enzymes of the bacteriochlorophyll biosynthesis pathway. there exist two fundamentally different forms of this enzyme. the oxygen-dependent form, encoded by the gene acsf, catalyzes the formation of the bacteriochlorophyll fifth ring using oxygen, whereas the oxygen-independent form encoded by the gene bche utilizes an oxygen atom extracted from water. the presence of acsf and bche genes was surveyed in various phototrophic pr ...201323396335
plant-bacterium interactions analyzed by proteomics.the evolution of the plant immune response has resulted in a highly effective defense system that is able to resist potential attack by microbial pathogens. the primary immune response is referred to as pathogen associated molecular pattern (pamp) triggered immunity and has evolved to recognize common features of microbial pathogens. in response to the delivery of pathogen effector proteins, plants acquired r proteins to fight against pathogen attack. r-dependent defense response is important in ...201323424014
the methanol dehydrogenase gene, mxaf, as a functional and phylogenetic marker for proteobacterial methanotrophs in natural environments.the mxaf gene, coding for the large (α) subunit of methanol dehydrogenase, is highly conserved among distantly related methylotrophic species in the alpha-, beta- and gammaproteobacteria. it is ubiquitous in methanotrophs, in contrast to other methanotroph-specific genes such as the pmoa and mmox genes, which are absent in some methanotrophic proteobacterial genera. this study examined the potential for using the mxaf gene as a functional and phylogenetic marker for methanotrophs. mxaf and 16s r ...201323451130
insights into denitrification in methylotenera mobilis from denitrification pathway and methanol metabolism mutants.we investigated phenotypes of mutants of methylotenera mobilis jlw8 with lesions in genes predicted to encode functions of the denitrification pathway, as well as mutants with mutations in methanol dehydrogenase-like structural genes xoxf1 and xoxf2, in order to obtain insights into denitrification and methanol metabolism by this bacterium. by monitoring the accumulation of nitrous oxide, we demonstrate that a periplasmic nitrate reductase, nad(p)-linked and copper-containing nitrite reductases, ...201323475964
lateral transfer and gc content of bacterial resistant genes. 201323487592
elucidation of the role of the methylene-tetrahydromethanopterin dehydrogenase mtda in the tetrahydromethanopterin-dependent oxidation pathway in methylobacterium extorquens am1.the methylotroph methylobacterium extorquens am1 oxidizes methanol and methylamine to formaldehyde and subsequently to formate, an intermediate that serves as the branch point between assimilation (formation of biomass) and dissimilation (oxidation to co₂). the oxidation of formaldehyde to formate is dephosphotetrahydromethanopterin (dh₄mpt) dependent, while the assimilation of carbon into biomass is tetrahydrofolate (h₄f) dependent. this bacterium contains two different enzymes, mtda and mtdb, ...201323504017
studying the microbiology of the indoor environment.the majority of people in the developed world spend more than 90% of their lives indoors. here, we examine our understanding of the bacteria that co-inhabit our artificial world and how they might influence human health.201323514020
the general stress response factor ecfg regulates expression of the c-2 hopanoid methylase hpnp in rhodopseudomonas palustris tie-1.lipid molecules preserved in sedimentary rocks facilitate the reconstruction of events that have shaped the evolution of the earth's biosphere. a key limitation for the interpretation of many of these molecular fossils is that their biological roles are still poorly understood. here, we use rhodopseudomonas palustris tie-1 to identify factors that induce biosynthesis of 2-methyl hopanoids (2-mebhps), progenitors of 2-methyl hopanes, one of the most abundant biomarkers in the rock record. this is ...201323524612
navigating the b(12) road: assimilation, delivery, and disorders of cobalamin.the reactivity of the cobalt-carbon bond in cobalamins is the key to their chemical versatility, supporting both methyl transfer and isomerization reactions. during evolution of higher eukaryotes that utilize vitamin b12, the high reactivity of the cofactor coupled with its low abundance pressured development of an efficient system for uptake, assimilation, and delivery of the cofactor to client b12-dependent enzymes. although most proteins suspected to be involved in b12 trafficking were discov ...201323539619
Refresh
firstprev
123456789
nextlast
Displaying items 501 - 600 of 819