Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| rhizobium ecuadorense sp. nov., an indigenous n2-fixing symbiont of the ecuadorian common bean (phaseolus vulgaris l.) genetic pool. | there are two major centres of genetic diversification of common bean (phaseolus vilgaris l.), the mesoamerican and the andean, and the legume is capable of establishing nitrogen-fixing symbioses with several rhizobia; rhizobium etli seems to be the dominant species in both centres. another genetic pool of common bean, in peru and ecuador, is receiving increasing attention, and studies of microsymbionts from the region can help to increase our knowledge about coevolution of this symbiosis. we ha ... | 2015 | 26297041 |
| quinol oxidase encoded by cyoabcd in rhizobium etli cfn42 is regulated by actsr and is crucial for growth at low ph or low iron conditions. | rhizobium etli aerobically respires with several terminal oxidases. the quinol oxidase (cyo) encoded by cyoabcd is needed for efficient adaptation to low oxygen conditions and cyo transcription is upregulated at low oxygen. this study sought to determine how transcription of the cyo operon is regulated. the 5' sequence upstream of cyo was analysed in silico and revealed putative binding sites for actr of the actsr two-component regulatory system. the expression of cyo was decreased in an actsr m ... | 2015 | 26297648 |
| a unique uracil-dna binding protein of the uracil dna glycosylase superfamily. | uracil dna glycosylases (udgs) are an important group of dna repair enzymes, which pioneer the base excision repair pathway by recognizing and excising uracil from dna. based on two short conserved sequences (motifs a and b), udgs have been classified into six families. here we report a novel udg, udgx, from mycobacterium smegmatis and other organisms. udgx specifically recognizes uracil in dna, forms a tight complex stable to sodium dodecyl sulphate, 2-mercaptoethanol, urea and heat treatment, ... | 2015 | 26304551 |
| a four-helix bundle stores copper for methane oxidation. | methane-oxidizing bacteria (methanotrophs) require large quantities of copper for the membrane-bound (particulate) methane monooxygenase. certain methanotrophs are also able to switch to using the iron-containing soluble methane monooxygenase to catalyse methane oxidation, with this switchover regulated by copper. methane monooxygenases are nature's primary biological mechanism for suppressing atmospheric levels of methane, a potent greenhouse gas. furthermore, methanotrophs and methane monooxyg ... | 2015 | 26308900 |
| phylogenetic co-occurrence of exor, exos, and chvi, components of the rsi bacterial invasion switch, suggests a key adaptive mechanism regulating the transition between free-living and host-invading phases in rhizobiales. | both bacterial symbionts and pathogens rely on their host-sensing mechanisms to activate the biosynthetic pathways necessary for their invasion into host cells. the gram-negative bacterium sinorhizobium meliloti relies on its rsi (exor-exos-chvi) invasion switch to turn on the production of succinoglycan, an exopolysaccharide required for its host invasion. recent whole-genome sequencing efforts have uncovered putative components of rsi-like invasion switches in many other symbiotic and pathogen ... | 2015 | 26309130 |
| sinorhizobium meliloti phage φm9 defines a new group of t4 superfamily phages with unusual genomic features but a common t=16 capsid. | relatively little is known about the phages that infect agriculturally important nitrogen-fixing rhizobial bacteria. here we report the genome and cryo-electron microscopy structure of the sinorhizobium meliloti-infecting t4 superfamily phage φm9. this phage and its close relative rhizobium phage vb_rlem_p10vf define a new group of t4 superfamily phages. these phages are distinctly different from the recently characterized cyanophage-like s. meliloti phages of the φm12 group. structurally, φm9 h ... | 2015 | 26311868 |
| enhancing flavonoid production by systematically tuning the central metabolic pathways based on a crispr interference system in escherichia coli. | the limited supply of intracellular malonyl-coa in escherichia coli impedes the biological synthesis of polyketides, flavonoids and biofuels. here, a clustered regularly interspaced short palindromic repeats (crispr) interference system was constructed for fine-tuning central metabolic pathways to efficiently channel carbon flux toward malonyl-coa. using synthetic sgrna to silence candidate genes, genes that could increase the intracellular malonyl-coa level by over 223% were used as target gene ... | 2015 | 26323217 |
| evolution of intra-specific regulatory networks in a multipartite bacterial genome. | reconstruction of the regulatory network is an important step in understanding how organisms control the expression of gene products and therefore phenotypes. recent studies have pointed out the importance of regulatory network plasticity in bacterial adaptation and evolution. the evolution of such networks within and outside the species boundary is however still obscure. sinorhizobium meliloti is an ideal species for such study, having three large replicons, many genomes available and a signifi ... | 2015 | 26340565 |
| mercury reduction and methyl mercury degradation by the soil bacterium xanthobacter autotrophicus py2. | two previously uncharacterized potential broad-spectrum mercury (hg) resistance operons (mer) are present on the chromosome of the soil alphaproteobacteria xanthobacter autotrophicus py2. these operons, mer1 and mer2, contain two features which are commonly found in mer operons in the genomes of soil and marine alphaproteobacteria, but are not present in previously characterized mer operons: a gene for the mercuric reductase (mera) that encodes an alkylmercury lyase domain typical of those found ... | 2015 | 26341208 |
| rapd-inferred genetic variability of some indigenous rhizobium leguminosarum isolates from red clover (trifolium pratense l.) nodules. | the application of commercial rhizobial inoculants to legume crops is proving to be an alternative to synthetic fertilizer use. the challenge for sustainable agriculture resides in the compatibility between crop, inoculants and environmental conditions. the evaluation of symbiotic efficiency and genetic diversity of indigenous rhizobial strains could lead to the development of better inoculants and increased crop production. the genetic variability of 32 wild indigenous rhizobial isolates was as ... | 2015 | 26344027 |
| molecular insights into cold active polygalacturonase enzyme for its potential application in food processing. | pectin is a complex structural heteropolysaccharide that require numerous pectinolytic enzymes for its complete degradation. polygalacturonase from mesophilic or thermophilic origin are being widely used in fruit and vegetable processing in the recent decades to degrade pectic substances. recently cold active pectinases are finding added advantages over meso and thermophilic counterparts, to use in industrial scale particularly in food processing industry. they facilitate in conservation of seve ... | 2014 | 26344963 |
| molecular insights into cold active polygalacturonase enzyme for its potential application in food processing. | pectin is a complex structural heteropolysaccharide that require numerous pectinolytic enzymes for its complete degradation. polygalacturonase from mesophilic or thermophilic origin are being widely used in fruit and vegetable processing in the recent decades to degrade pectic substances. recently cold active pectinases are finding added advantages over meso and thermophilic counterparts, to use in industrial scale particularly in food processing industry. they facilitate in conservation of seve ... | 2014 | 26344963 |
| free-air co2 enrichment (face) reduces the inhibitory effect of soil nitrate on n2 fixation of pisum sativum. | additional carbohydrate supply resulting from enhanced photosynthesis under predicted future elevated co2 is likely to increase symbiotic nitrogen (n) fixation in legumes. this study examined the interactive effects of atmospheric co2 and nitrate (no3(-)) concentration on the growth, nodulation and n fixation of field pea (pisum sativum) in a semi-arid cropping system. | 2015 | 26346721 |
| free-air co2 enrichment (face) reduces the inhibitory effect of soil nitrate on n2 fixation of pisum sativum. | additional carbohydrate supply resulting from enhanced photosynthesis under predicted future elevated co2 is likely to increase symbiotic nitrogen (n) fixation in legumes. this study examined the interactive effects of atmospheric co2 and nitrate (no3(-)) concentration on the growth, nodulation and n fixation of field pea (pisum sativum) in a semi-arid cropping system. | 2015 | 26346721 |
| metabolomics reveals differences of metal toxicity in cultures of pseudomonas pseudoalcaligenes kf707 grown on different carbon sources. | co-contamination of metals and organic pollutants is a global problem as metals interfere with the metabolism of complex organics by bacteria. based on a prior observation that metal tolerance was altered by the sole carbon source being used for growth, we sought to understand how metal toxicity specifically affects bacteria using an organic pollutant as their sole carbon source. to this end metabolomics was used to compare cultures of pseudomonas pseudoalcaligenes kf707 grown on either biphenyl ... | 2015 | 26347721 |
| adhesins involved in attachment to abiotic surfaces by gram-negative bacteria. | during the first step of biofilm formation, initial attachment is dictated by physicochemical and electrostatic interactions between the surface and the bacterial envelope. depending on the nature of these interactions, attachment can be transient or permanent. to achieve irreversible attachment, bacterial cells have developed a series of surface adhesins promoting specific or nonspecific adhesion under various environmental conditions. this article reviews the recent advances in our understandi ... | 2015 | 26350310 |
| knotted1-like homeobox 3: a new regulator of symbiotic nodule development. | knox transcription factors (tfs) regulate different aspects of plant development essentially through their effects on phytohormone metabolism. in particular, knox tf shootmeristemless activates the cytokinin biosynthesis isopentenyl transferase (ipt) genes in the shoot apical meristem. however, the role of knox tfs in symbiotic nodule development and their possible effects on phytohormone metabolism during nodulation have not been studied to date. cytokinin is a well-known regulator of nodule de ... | 2015 | 26351356 |
| the diversity of pea microsymbionts in various types of soils and their effects on plant host productivity. | the growth and yield of peas cultivated on eight different soils, as well as the diversity of pea microsymbionts derived from these soils were investigated in the present study. the experimental plot was composed of soils that were transferred from different parts of poland more than a century ago. the soils were located in direct vicinity of each other in the experimental plot. all soils examined contained pea microsymbionts, which were suggested to belong to rhizobium leguminosarum sv. viciae ... | 2015 | 26370165 |
| abundant toxin-related genes in the genomes of beneficial symbionts from deep-sea hydrothermal vent mussels. | bathymodiolus mussels live in symbiosis with intracellular sulfur-oxidizing (sox) bacteria that provide them with nutrition. we sequenced the sox symbiont genomes from two bathymodiolus species. comparison of these symbiont genomes with those of their closest relatives revealed that the symbionts have undergone genome rearrangements, and up to 35% of their genes may have been acquired by horizontal gene transfer. many of the genes specific to the symbionts were homologs of virulence genes. we di ... | 2015 | 26371554 |
| characterization of the temperate phage vb_rlem_ppf1 and its site-specific integration into the rhizobium leguminosarum f1 genome. | bacteriophages may play an important role in regulating population size and diversity of the root nodule symbiont rhizobium leguminosarum, as well as participating in horizontal gene transfer. although phages that infect this species have been isolated in the past, our knowledge of their molecular biology, and especially of genome composition, is extremely limited, and this lack of information impacts on the ability to assess phage population dynamics and limits potential agricultural applicatio ... | 2016 | 26377943 |
| gene expression of type vi secretion system associated with environmental survival in acidovorax avenae subsp. avenae by principle component analysis. | valine glycine repeat g (vgrg) proteins are regarded as one of two effectors of type vi secretion system (t6ss) which is a complex multi-component secretion system. in this study, potential biological roles of t6ss structural and vgrg genes in a rice bacterial pathogen, acidovorax avenae subsp. avenae (aaa) rs-1, were evaluated under seven stress conditions using principle component analysis of gene expression. the results showed that growth of the pathogen was reduced by h₂o₂ and paraquat-induc ... | 2015 | 26378528 |
| high-quality permanent draft genome sequence of rhizobium sullae strain wsm1592; a hedysarum coronarium microsymbiont from sassari, italy. | rhizobium sullae strain wsm1592 is an aerobic, gram-negative, non-spore-forming rod that was isolated from an effective nitrogen (n2) fixing root nodule formed on the short-lived perennial legume hedysarum coronarium (also known as sulla coronaria or sulla). wsm1592 was isolated from a nodule recovered from h. coronarium roots located in ottava, bordering sassari, sardinia in 1995. wsm1592 is highly effective at fixing nitrogen with h. coronarium, and is currently the commercial sulla inoculant ... | 2015 | 26380632 |
| genome sequence of rhizobium ecuadorense strain cnpso 671t, an indigenous n2-fixing symbiont of the ecuadorian common bean (phaseolus vulgaris l.) genetic pool. | rhizobium ecuadorense cnpso 671(t) was isolated from a common bean nodule in ecuador. the draft genome brings novelty about indigenous rhizobial species in centers of genetic diversity of the legume. | 2015 | 26383667 |
| iron response regulator protein irrb in magnetospirillum gryphiswaldense msr-1 helps control the iron/oxygen balance, oxidative stress tolerance, and magnetosome formation. | magnetotactic bacteria are capable of forming nanosized, membrane-enclosed magnetosomes under iron-rich and oxygen-limited conditions. the complete genomic sequence of magnetospirillum gryphiswaldense strain msr-1 has been analyzed and found to contain five fur homologue genes whose protein products are predicted to be involved in iron homeostasis and the response to oxidative stress. of these, only the mgmsrv2_3149 gene (irrb) was significantly downregulated under high-iron and low-oxygen condi ... | 2015 | 26386052 |
| single cells within the puerto rico trench suggest hadal adaptation of microbial lineages. | hadal ecosystems are found at a depth of 6,000 m below sea level and below, occupying less than 1% of the total area of the ocean. the microbial communities and metabolic potential in these ecosystems are largely uncharacterized. here, we present four single amplified genomes (sags) obtained from 8,219 m below the sea surface within the hadal ecosystem of the puerto rico trench (prt). these sags are derived from members of deep-sea clades, including the thaumarchaeota and sar11 clade, and two ar ... | 2015 | 26386059 |
| rhizobial diversity and nodulation characteristics of the extremely promiscuous legume sophora flavescens. | in present study, we report our extensive survey on the diversity and biogeography of rhizobia associated with sophora flavescens, a sophocarpidine (matrine)-containing medicinal legume. we additionally investigated the cross nodulation, infection pattern, light and electron microscopies of root nodule sections of s. flavescens infected by various rhizobia. seventeen genospecies of rhizobia belonging to five genera with seven types of symbiotic nodc genes were found to nodulate s. flavescens in ... | 2015 | 26389798 |
| loss of the nodule-specific cysteine rich peptide, ncr169, abolishes symbiotic nitrogen fixation in the medicago truncatula dnf7 mutant. | host compatible rhizobia induce the formation of legume root nodules, symbiotic organs within which intracellular bacteria are present in plant-derived membrane compartments termed symbiosomes. in medicago truncatula nodules, the sinorhizobium microsymbionts undergo an irreversible differentiation process leading to the development of elongated polyploid noncultivable nitrogen fixing bacteroids that convert atmospheric dinitrogen into ammonia. this terminal differentiation is directed by the hos ... | 2015 | 26401023 |
| site-specific distribution and competitive ability of indigenous bean-nodulating rhizobia isolated from organic fields in minnesota. | organic dry bean production systems have received increasing interest in many regions of the us, including minnesota. thus, improving biological n2 fixation would be highly beneficial for organic crop production. to date, only limited work has been done to select efficient n2-fixing rhizobia for organic dry bean production. in this study, soil samples from 25 organic fields in minnesota, with a previous cropping history of dry beans, soybeans or both, were collected during may to july 2012. gene ... | 2015 | 26403588 |
| symbiotic potential and survival of native rhizobia kept on different carriers. | native rhizobia are ideal for use as commercial legume inoculants. the characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. the objective of this study was to investigate the effects of peat (peat), perlite sugarcane bagasse (psb), carboxymethyl cellulose plus starch (cmcs), and yeast extract mannitol supplemented with mannitol (yemm) on the survival, nodulation potential and n2 fixation capacity of the native strains ... | 2015 | 26413054 |
| mini-tn7 vectors for stable expression of diguanylate cyclase pled* in gram-negative bacteria. | the cyclic diguanylate (c-di-gmp) is currently considered an ubiquitous second messenger in bacteria that influences a wide range of cellular processes. one of the methodological approaches to unravel c-di-gmp regulatory networks involves raising the c-di-gmp intracellular levels, e.g. by expressing a diguanylate cyclase (dgc), to provoke phenotypic changes. | 2015 | 26415513 |
| the sugar kinase that is necessary for the catabolism of rhamnose in rhizobium leguminosarum directly interacts with the abc transporter necessary for rhamnose transport. | rhamnose catabolism in rhizobium leguminosarum was found to be necessary for the ability of the organism to compete for nodule occupancy. characterization of the locus necessary for the catabolism of rhamnose showed that the transport of rhamnose was dependent upon a carbohydrate uptake transporter 2 (cut2) abc transporter encoded by rhastpq and on the presence of rhak, a protein known to have sugar kinase activity. a linker-scanning mutagenesis analysis of rhak showed that the kinase and transp ... | 2015 | 26416834 |
| mgte from rhizobium leguminosarum is a mg²⁺ channel essential for growth at low ph and n2 fixation on specific plants. | mgte is predicted to be a rhizobium leguminosarum channel and is essential for growth when both mg²⁺ is limiting and the ph is low. n₂was only fixed at 8% of the rate of wild type when the crop legume pisum sativum was inoculated with an mgte mutant of r. leguminosarum and, although bacteroids were present, they were few in number and not fully developed. r. leguminosarum mgte was also essential for n₂fixation on the native legume vicia hirsuta but not when in symbiosis with vicia faba. the impo ... | 2015 | 26422403 |
| the emergence of 2-oxoglutarate as a master regulator metabolite. | the metabolite 2-oxoglutarate (also known as α-ketoglutarate, 2-ketoglutaric acid, or oxoglutaric acid) lies at the intersection between the carbon and nitrogen metabolic pathways. this compound is a key intermediate of one of the most fundamental biochemical pathways in carbon metabolism, the tricarboxylic acid (tca) cycle. in addition, 2-oxoglutarate also acts as the major carbon skeleton for nitrogen-assimilatory reactions. experimental data support the conclusion that intracellular levels of ... | 2015 | 26424716 |
| biochemistry and genetics of acc deaminase: a weapon to "stress ethylene" produced in plants. | 1-aminocyclopropane-1-carboxylate deaminase (accd), a pyridoxal phosphate-dependent enzyme, is widespread in diverse bacterial and fungal species. owing to accd activity, certain plant associated bacteria help plant to grow under biotic and abiotic stresses by decreasing the level of "stress ethylene" which is inhibitory to plant growth. accd breaks down acc, an immediate precursor of ethylene, to ammonia and α-ketobutyrate, which can be further metabolized by bacteria for their growth. acc deam ... | 2015 | 26441873 |
| legume-rhizobia signal exchange: promiscuity and environmental effects. | although signal exchange between legumes and their rhizobia is among the best-known examples of this biological process, most of the more characterized data comes from just a few legume species and environmental stresses. although a relative wealth of information is available for some model legumes and some of the major pulses such as soybean, little is known about tropical legumes. this relative disparity in current knowledge is also apparent in the research on the effects of environmental stre ... | 2015 | 26441880 |
| rhizosphere ecology of lumichrome and riboflavin, two bacterial signal molecules eliciting developmental changes in plants. | lumichrome and riboflavin are novel molecules from rhizobial exudates that stimulate plant growth. reported studies have revealed major developmental changes elicited by lumichrome at very low nanomolar concentrations (5 nm) in plants, which include early initiation of trifoliate leaves, expansion of unifoliate and trifoliate leaves, increased stem elongation and leaf area, and consequently greater biomass accumulation in monocots and dicots. but higher lumichrome concentration (50 nm) depressed ... | 2015 | 26442016 |
| inter-organismal signaling and management of the phytomicrobiome. | the organisms of the phytomicrobiome use signal compounds to regulate aspects of each other's behavior. legumes use signals (flavonoids) to regulate rhizobial nod gene expression during establishment of the legume-rhizobia n2-fixation symbiosis. lipochitooligosaccharides (lcos) produced by rhizobia act as return signals to the host plant and are recognized by specific lysine motif receptor like kinases, which triggers a signal cascade leading to nodulation of legume roots. lcos also enhance plan ... | 2015 | 26442036 |
| mining the phytomicrobiome to understand how bacterial coinoculations enhance plant growth. | in previous work, we showed that coinoculating rhizobium leguminosarum bv. viciae 128c53 and bacillus simplex 30n-5 onto pisum sativum l. roots resulted in better nodulation and increased plant growth. we now expand this research to include another alpha-rhizobial species as well as a beta-rhizobium, burkholderia tuberum stm678. we first determined whether the rhizobia were compatible with b. simplex 30n-5 by cross-streaking experiments, and then medicago truncatula and melilotus alba were coino ... | 2015 | 26442090 |
| a jaz protein in astragalus sinicus interacts with a leghemoglobin through the tify domain and is involved in nodule development and nitrogen fixation. | leghemoglobins (lbs) play an important role in legumes-rhizobia symbiosis. lbs bind o2 and protect nitrogenase activity from damage by o2 in nodules, therefore, they are regarded as a marker of active nitrogen fixation in nodules. additionally, lbs are involved in the nitric oxide (no) signaling pathway, acting as a no scavenger during nodule development and nitrogen fixation. however, regulators responsible for lb expression and modulation of lb activity have not been characterized. in our prev ... | 2015 | 26460857 |
| isolation and characterization of a crude oil degrading bacteria from formation water: comparative genomic analysis of environmental ochrobactrum intermedium isolate versus clinical strains. | in this study, we isolated an environmental clone of ochrobactrum intermedium, strain 2745-2, from the formation water of changqing oilfield in shanxi, china, which can degrade crude oil. strain 2745-2 is aerobic and rod-shaped with optimum growth at 42 °c and ph 5.5. we sequenced the genome and found a single chromosome of 4 800 175 bp, with a g+c content of 57.63%. sixty rnas and 4737 protein-coding genes were identified: many of the genes are responsible for the degradation, emulsification, a ... | 2015 | 26465134 |
| global and targeted lipid analysis of gemmata obscuriglobus reveals the presence of lipopolysaccharide, a signature of the classical gram-negative outer membrane. | planctomycete bacteria possess many unusual cellular properties, contributing to a cell plan long considered to be unique among the bacteria. however, data from recent studies are more consistent with a modified gram-negative cell plan. a key feature of the gram-negative plan is the presence of an outer membrane (om), for which lipopolysaccharide (lps) is a signature molecule. despite genomic evidence for an om in planctomycetes, no biochemical verification has been reported. we attempted to det ... | 2016 | 26483522 |
| global and targeted lipid analysis of gemmata obscuriglobus reveals the presence of lipopolysaccharide, a signature of the classical gram-negative outer membrane. | planctomycete bacteria possess many unusual cellular properties, contributing to a cell plan long considered to be unique among the bacteria. however, data from recent studies are more consistent with a modified gram-negative cell plan. a key feature of the gram-negative plan is the presence of an outer membrane (om), for which lipopolysaccharide (lps) is a signature molecule. despite genomic evidence for an om in planctomycetes, no biochemical verification has been reported. we attempted to det ... | 2016 | 26483522 |
| genome-wide survey of two-component signal transduction systems in the plant growth-promoting bacterium azospirillum. | two-component systems (tcs) play critical roles in sensing and responding to environmental cues. azospirillum is a plant growth-promoting rhizobacterium living in the rhizosphere of many important crops. despite numerous studies about its plant beneficial properties, little is known about how the bacterium senses and responds to its rhizospheric environment. the availability of complete genome sequenced from four azospirillum strains (a. brasilense sp245 and cbg 497, a. lipoferum 4b and azospiri ... | 2015 | 26489830 |
| conjugative transfer of a derivative of the incp-1α plasmid rp4 and establishment of transconjugants in the indigenous bacterial community of poplar plants. | the persistence of traits introduced into the indigenous bacterial community of poplar plants was investigated using bioluminescence mediated by the luc gene. three endophytic bacterial strains provided with the incp-1α plasmid rp4-tn-luc were used to inoculate poplar cuttings at different phenological stages. screening of isolates by bioluminescence and real-time pcr detection of the luc gene revealed stable persistence for at least 10 weeks. although the inoculated strains became established w ... | 2015 | 26490946 |
| identification and classification of rhizobia by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. | mass spectrometry (ms) has been widely used for specific, sensitive and rapid analysis of proteins and has shown a high potential for bacterial identification and characterization. type strains of four species of rhizobia and escherichia coli dh5α were employed as reference bacteria to optimize various parameters for identification and classification of species of rhizobia by matrix-assisted laser desorption/ionization time-of-flight ms (maldi tof ms). the parameters optimized included culture m ... | 2015 | 26500417 |
| a structure-based classification of class a β-lactamases, a broadly diverse family of enzymes. | for medical biologists, sequencing has become a commonplace technique to support diagnosis. rapid changes in this field have led to the generation of large amounts of data, which are not always correctly listed in databases. this is particularly true for data concerning class a β-lactamases, a group of key antibiotic resistance enzymes produced by bacteria. many genomes have been reported to contain putative β-lactamase genes, which can be compared with representative types. we analyzed several ... | 2016 | 26511485 |
| a structure-based classification of class a β-lactamases, a broadly diverse family of enzymes. | for medical biologists, sequencing has become a commonplace technique to support diagnosis. rapid changes in this field have led to the generation of large amounts of data, which are not always correctly listed in databases. this is particularly true for data concerning class a β-lactamases, a group of key antibiotic resistance enzymes produced by bacteria. many genomes have been reported to contain putative β-lactamase genes, which can be compared with representative types. we analyzed several ... | 2016 | 26511485 |
| the yhs-domain of an adenylyl cyclase from mycobacterium phlei is a probable copper-sensor module. | yhs-domains are small protein modules which have been proposed to bind transition-metal ions like the related trash-domains. they are found in a variety of enzymes including copper-transporting atpases and adenylyl cyclases. here we investigate a class iiic adenylyl cyclase from mycobacterium phlei which contains a c-terminal yhs-domain linked to the catalytic domain by a peptide of 8 amino acids. we expressed the isolated catalytic domain and the full-length enzyme in e. coli. the catalytic dom ... | 2015 | 26512893 |
| rhizobium acidisoli sp. nov., isolated from root nodules of phaseolus vulgaris in acid soils. | two gram-negative, aerobic, non-motile, rod-shaped bacterial strains, fh13t and fh23, representing a novel group of rhizobium isolated from root nodules of phaseolus vulgaris in mexico, were studied by a polyphasic analysis. phylogeny of 16s rrna gene sequences revealed them to be members of the genus rhizobium related most closely to 'rhizobium anhuiense' ccbau 23252 (99.7 % similarity), rhizobium leguminosarum usda 2370t (98.6 %), and rhizobium sophorae ccbau 03386t and others ( ≤ 98.3 %). in ... | 2016 | 26530784 |
| plant growth-promoting bacteria as inoculants in agricultural soils. | plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. plant growth-promoting bacteria (pgpb) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. several important bacterial characteristics, such as biological nitrogen fixation ... | 2015 | 26537605 |
| ensifer-mediated transformation: an efficient non-agrobacterium protocol for the genetic modification of rice. | while agrobacterium-mediated transformation (amt) remains the most widely used technique for gene transfer in plants, interest exists for the use of non-agrobacterium gene delivery systems due to freedom-to-operate issues that remain with amt across several jurisdictions. in addition, the plant pathogenic mode of action of agrobacterium tumefaciens significantly increases the costs to passage engineered cultivars through the regulatory process. ensifer adhaerens (ov14) is a soil-related bacteriu ... | 2015 | 26543735 |
| inoculation of new rhizobial isolates improve nutrient uptake and growth of bean (phaseolus vulgaris) and arugula (eruca sativa). | in the current agricultural model, the massive use of chemical fertilizer causes environmental and economic losses. inoculation of plant-growth-promoting (pgp) nitrogen-fixing bacteria is an alternative to the use of nitrogen, phosphorus and potassium fertilizers. in this study, rhizobia strains isolated from common bean (phaseolus vulgaris) root nodules were evaluated in an effort to identify an efficient nitrogen-fixing rhizobia strain able to improve bean germination and growth. | 2016 | 26564333 |
| cyclic di-gmp regulates multiple cellular functions in the symbiotic alphaproteobacterium sinorhizobium meliloti. | sinorhizobium meliloti undergoes major lifestyle changes between planktonic states, biofilm formation, and symbiosis with leguminous plant hosts. in many bacteria, the second messenger 3',5'-cyclic di-gmp (c-di-gmp, or cdg) promotes a sessile lifestyle by regulating a plethora of processes involved in biofilm formation, including motility and biosynthesis of exopolysaccharides (eps). here, we systematically investigated the role of cdg in s. meliloti rm2011 encoding 22 proteins putatively associ ... | 2016 | 26574513 |
| analyzing the molecular mechanism of lipoprotein localization in brucella. | bacterial lipoproteins possess diverse structure and functionality, ranging from bacterial physiology to pathogenic processes. as such many lipoproteins, originating from brucella are exploited as potential vaccines to countermeasure brucellosis infection in the host. these membrane proteins are translocated from the cytoplasm to the cell membrane where they are anchored peripherally by a multifaceted targeting mechanism. although much research has focused on the identification and classificatio ... | 2015 | 26579096 |
| systemic colonization of clover (trifolium repens) by clostridium botulinum strain 2301. | in recent years, cases of botulism in cattle and other farm animals and also in farmers increased dramatically. it was proposed, that these cases could be affiliated with the spreading of compost or other organic manures contaminated with clostridium botulinum spores on farm land. thus, soils and fodder plants and finally farm animals could be contaminated. therefore, the colonization behavior and interaction of the botulinum neurotoxin (bont d) producing c. botulinum strain 2301 and the non-tox ... | 2015 | 26583010 |
| a bioinformatics insight to rhizobial globins: gene identification and mapping, polypeptide sequence and phenetic analysis, and protein modeling. | globins (glbs) are proteins widely distributed in organisms. three evolutionary families have been identified in glbs: the m, s and t glb families. the m glbs include flavohemoglobins (fhbs) and single-domain glbs (sdgbs); the s glbs include globin-coupled sensors (gcss), protoglobins and sensor single domain globins, and the t glbs include truncated glbs (thbs). structurally, the m and s glbs exhibit 3/3-folding whereas the t glbs exhibit 2/2-folding. glbs are widespread in bacteria, including ... | 2015 | 26594329 |
| establishing a role for bacterial cellulose in environmental interactions: lessons learned from diverse biofilm-producing proteobacteria. | bacterial cellulose (bc) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. biosynthesis of bc-containing biofilms occurs in a variety of proteobacteria that inhabit diverse ecological niches. the enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of bc are equally as diverse. though the magnitude and environmental consequences of bc production are species-specific, the common role of bc-containing biofilms is to ... | 2015 | 26635751 |
| [the effect of cadmium on the efficiency of development of legume-rhizobium symbiosis]. | screening of nodule bacteria (rhizobia) forming symbiotic relationships with legumes has been performed in order to isolate strains resistant to cadmium ions in a wide range of concentrations (6-132 mg/kg). the effect ofcadmium salts (6, 12, 24 mg/kg) on the legume-rhizobium symbiosis ofthe pea pisum sativum l. with rhizobium leguminosarum and of the fodder galega galega orientalis lam. with rhizobium galegae has been studied under experimental laboratory conditions. no statistically significant ... | 2016 | 26638242 |
| modification of the 1-phosphate group during biosynthesis of capnocytophaga canimorsus lipid a. | capnocytophaga canimorsus, a commensal bacterium of dog's mouth flora causing severe infections in humans after dog bites or scratches, has a lipopolysaccharide (lps) (endotoxin) with low-inflammatory lipid a. in particular, it contains a phosphoethanolamine (p-etn) instead of a free phosphate group at the c-1 position of the lipid a backbone, usually present in highly toxic enterobacterial gram-negative lipid a. here we show that the c. canimorsus genome comprises a single operon encoding a lip ... | 2016 | 26644381 |
| helicobacter pylori resists the antimicrobial activity of calprotectin via lipid a modification and associated biofilm formation. | helicobacter pylori is one of several pathogens that persist within the host despite a robust immune response. h. pylori elicits a proinflammatory response from host epithelia, resulting in the recruitment of immune cells which manifests as gastritis. relatively little is known about how h. pylori survives antimicrobials, including calprotectin (cp), which is present during the inflammatory response. the data presented here suggest that one way h. pylori survives the nutrient sequestration by cp ... | 2015 | 26646009 |
| genome sequence of the clover symbiont rhizobium leguminosarum bv. trifolii strain cc275e. | rhizobium leguminosarum bv. trifolii strain cc275e is a highly effective, n2-fixing microsymbiont of white clover (trifolium repens l.). the bacterium has been widely used in both australia and new zealand as a clover seed inoculant and, as such, has delivered the equivalent of millions of dollars of nitrogen into these pastoral systems. r. leguminosarum strain cc275e is a rod-shaped, motile, gram-negative, non-spore forming bacterium. the genome was sequenced on an illumina miseq instrument usi ... | 2015 | 26649149 |
| mixed planting with a leguminous plant outperforms bacteria in promoting growth of a metal remediating plant through histidine synthesis. | the effectiveness of plant growth promoting bacteria (pgpb) in improving metal phytoremediation is still limited by stunted plant growth under high soil metal concentrations. meanwhile, mixed planting with leguminous plants is known to improve yield in nutrient deficient soils but the use of a metal tolerant legume to enhance metal tolerance of a phytoremediator has not been explored. we compared the use of pseudomonas brassicacearum, rhizobium leguminosarum, and the metal tolerant leguminous pl ... | 2016 | 26682469 |
| genetic analysis reveals the essential role of nitrogen phosphotransferase system components in sinorhizobium fredii ccbau 45436 symbioses with soybean and pigeonpea plants. | the nitrogen phosphotransferase system (pts(ntr)) consists of ei(ntr), npr, and eiia(ntr). the active phosphate moiety derived from phosphoenolpyruvate is transferred through ei(ntr) and npr to eiia(ntr). sinorhizobium fredii can establish a nitrogen-fixing symbiosis with the legume crops soybean (as determinate nodules) and pigeonpea (as indeterminate nodules). in this study, s. fredii strains with mutations in ptsp and ptso (encoding ei(ntr) and npr, respectively) formed ineffective nodules on ... | 2016 | 26682851 |
| comparative analysis of prokaryotic communities associated with organic and conventional farming systems. | one of the most important challenges in agriculture is to determine the effectiveness and environmental impact of certain farming practices. the aim of present study was to determine and compare the taxonomic composition of the microbiomes established in soil following long-term exposure (14 years) to a conventional and organic farming systems (cfs and ofs accordingly). soil from unclared forest next to the fields was used as a control. the analysis was based on rt-pcr and pyrosequencing of 16s ... | 2015 | 26684619 |
| de novo assembly of the pea (pisum sativum l.) nodule transcriptome. | the large size and complexity of the garden pea (pisum sativum l.) genome hamper its sequencing and the discovery of pea gene resources. although transcriptome sequencing provides extensive information about expressed genes, some tissue-specific transcripts can only be identified from particular organs under appropriate conditions. in this study, we performed rna sequencing of polyadenylated transcripts from young pea nodules and root tips on an illumina gaiix system, followed by de novo transcr ... | 2015 | 26688806 |
| [antioxidative function of katg gene in rhizobium leguminosarum]. | catalase-peroxidase katg can protect bacteria from damage of reactive oxygen species. this study investigated the antioxidative function of catalase - peroxidase gene katg in rhizobium leguminosarum 3841. | 2015 | 26710603 |
| regulation of the rhaewrbma operon involved in l-rhamnose catabolism through two transcriptional factors, rhar and ccpa, in bacillus subtilis. | the bacillus subtilis rhaewrbma (formerly yuxg-yulbcde) operon consists of four genes encoding enzymes for l-rhamnose catabolism and the rhar gene encoding a deor-type transcriptional regulator. dnase i footprinting analysis showed that the rhar protein specifically binds to the regulatory region upstream of the rhaew gene, in which two imperfect direct repeats are included. gel retardation analysis revealed that the direct repeat farther upstream is essential for the high-affinity binding of rh ... | 2016 | 26712933 |
| discrete responses to limitation for iron and manganese in agrobacterium tumefaciens: influence on attachment and biofilm formation. | transition metals such as iron and manganese are crucial trace nutrients for the growth of most bacteria, functioning as catalytic cofactors for many essential enzymes. dedicated uptake and regulatory systems have evolved to ensure their acquisition for growth, while preventing toxicity. transcriptomic analysis of the iron- and manganese-responsive regulons of agrobacterium tumefaciens revealed that there are discrete regulatory networks that respond to changes in iron and manganese levels. comp ... | 2016 | 26712936 |
| transcriptome profiling of a rhizobium leguminosarum bv. trifolii rosr mutant reveals the role of the transcriptional regulator rosr in motility, synthesis of cell-surface components, and other cellular processes. | rhizobium leguminosarum bv. trifolii is a soil bacterium capable of establishing a symbiotic relationship with red clover (trifolium pratense). the presence of surface polysaccharides and other extracellular components as well as motility and competitiveness are essential traits for both adaptation of this bacterium to changing environmental conditions and successful infection of host plant roots. the r. leguminosarum bv. trifolii rosr gene encodes a protein belonging to the family of ros/mucr t ... | 2015 | 26715155 |
| ancient evolution and recent evolution converge for the biodegradation of cyanuric acid and related triazines. | cyanuric acid was likely present on prebiotic earth, may have been a component of early genetic materials, and is synthesized industrially today on a scale of more than one hundred million pounds per year in the united states. in light of this, it is not surprising that some bacteria and fungi have a metabolic pathway that sequentially hydrolyzes cyanuric acid and its metabolites to release the nitrogen atoms as ammonia to support growth. the initial reaction that opens the s-triazine ring is ca ... | 2016 | 26729715 |
| the effect of root exudate 7,4'-dihydroxyflavone and naringenin on soil bacterial community structure. | our goal was to investigate how root exudate flavonoids influence the soil bacterial community structure and to identify members of the community that change their relative abundance in response to flavonoid exudation. using a model system that approximates flavonoid exudation of medicago sativa roots, we treated a soil with 7,4'-dihydroxyflavone and naringenin in two separate experiments using three different rates: medium (equivalent to the exudation rate of 7,4'-dihydroxyflavone from m. sativ ... | 2016 | 26752410 |
| the receiver of the agrobacterium tumefaciens vira histidine kinase forms a stable interaction with virg to activate virulence gene expression. | the plant pathogen agrobacterium tumefaciens carries a virulence gene system that is required for the initiation of crown gall tumors on susceptible plants. expression of the vir genes is activated by the vira/virg two component regulatory system. vira is a histidine kinase which signals the presence of certain chemicals found at the site of a plant wound. the receiver domain located at its carboxyl terminus defines vira as a hybrid histidine kinase. here, we show that the vira receiver interact ... | 2015 | 26779177 |
| the receiver of the agrobacterium tumefaciens vira histidine kinase forms a stable interaction with virg to activate virulence gene expression. | the plant pathogen agrobacterium tumefaciens carries a virulence gene system that is required for the initiation of crown gall tumors on susceptible plants. expression of the vir genes is activated by the vira/virg two component regulatory system. vira is a histidine kinase which signals the presence of certain chemicals found at the site of a plant wound. the receiver domain located at its carboxyl terminus defines vira as a hybrid histidine kinase. here, we show that the vira receiver interact ... | 2015 | 26779177 |
| multiplicity of sulfate and molybdate transporters and their role in nitrogen fixation in rhizobium leguminosarum bv. viciae rlv3841. | rhizobium leguminosarum rlv3841 contains at least three sulfate transporters, i.e., sulabcd, sulp1 and sulp2, and a single molybdate transporter, modabc. sulabcd is a high-affinity transporter whose mutation prevented growth on a limiting sulfate concentration, while sulp1 and sulp2 appear to be low-affinity sulfate transporters. modabc is the sole high-affinity molybdate transport system and is essential for growth with no3(-) as a nitrogen source on limiting levels of molybdate (<0.25 μm). how ... | 2016 | 26812045 |
| a multi-substrate approach for functional metagenomics-based screening for (hemi)cellulases in two wheat straw-degrading microbial consortia unveils novel thermoalkaliphilic enzymes. | functional metagenomics is a promising strategy for the exploration of the biocatalytic potential of microbiomes in order to uncover novel enzymes for industrial processes (e.g. biorefining or bleaching pulp). most current methodologies used to screen for enzymes involved in plant biomass degradation are based on the use of single substrates. moreover, highly diverse environments are used as metagenomic sources. however, such methods suffer from low hit rates of positive clones and hence the dis ... | 2016 | 26822785 |
| plant pathogens affecting the establishment of plant-symbiont interaction. | 2016 | 26834779 | |
| adaptive remodeling of the bacterial proteome by specific ribosomal modification regulates pseudomonas infection and niche colonisation. | post-transcriptional control of protein abundance is a highly important, underexplored regulatory process by which organisms respond to their environments. here we describe an important and previously unidentified regulatory pathway involving the ribosomal modification protein rimk, its regulator proteins rima and rimb, and the widespread bacterial second messenger cyclic-di-gmp (cdg). disruption of rimk affects motility and surface attachment in pathogenic and commensal pseudomonas species, wit ... | 2016 | 26845436 |
| the lps o-antigen in photosynthetic bradyrhizobium strains is dispensable for the establishment of a successful symbiosis with aeschynomene legumes. | the photosynthetic bradyrhizobia are able to use a nod-factor independent process to induce nitrogen-fixing nodules on some semi-aquatic aeschynomene species. these bacteria display a unique lps o-antigen composed of a new sugar, the bradyrhizose that is regarded as a key symbiotic factor due to its non-immunogenic character. in this study, to check this hypothesis, we isolated mutants affected in the o-antigen synthesis by screening a transposon mutant library of the ors285 strain for clones al ... | 2016 | 26849805 |
| medicago truncatula gaertn. as a model for understanding the mechanism of growth promotion by bacteria from rhizosphere and nodules of alfalfa. | the present study showed all the 16 strains isolated and identified from the alfalfa rhizosphere and nodules, and registered in genbank, to be good candidates for targeted use in studies addressing the rather weak known mechanism of plant growth promotion, including that of medicago truncatula, a molecular crop model. based on physiological, biochemical and molecular analysis, the 16 isolates obtained were ascribed to the following five families: bacillaceae, rhizobiaceae, xantomonadaceae, enter ... | 2016 | 26861677 |
| temperature-dependent expression of nodc and community structure of soybean-nodulating bradyrhizobia. | in order to assess the physiological responses of bradyrhizobia and competition for the nodulation of soybean at different temperatures, we investigated the expression of the nodc gene at 20, 25, and 30°c and the abilities of bacteria to nodulate soybean in microcosms at day/night cultivation temperatures of 23/18°c, 28/23°c, and 33/28°c for 16/8 h. we tested five bradyrhizobium usda strains: b. diazoefficiens usda 110(t) and 122, b. japonicum usda 123, and b. elkanii usda 31 and 76(t). the expr ... | 2016 | 26877137 |
| contributions of sinorhizobium meliloti transcriptional regulator dksa to bacterial growth and efficient symbiosis with medicago sativa. | the stringent response, mediated by the (p)ppgpp synthetase rela and the rna polymerase-binding protein dksa, is triggered by limiting nutrient conditions. for some bacteria, it is involved in regulation of virulence. we investigated the role of two dksa-like proteins from the gram-negative nitrogen-fixing symbiont sinorhizobium meliloti in free-living culture and in interaction with its host plant medicago sativa the two paralogs, encoded by the genes smc00469 and smc00049, differ in the consti ... | 2016 | 26883825 |
| interactions between ethylene, gibberellins, and brassinosteroids in the development of rhizobial and mycorrhizal symbioses of pea. | the regulation of arbuscular mycorrhizal development and nodulation involves complex interactions between the plant and its microbial symbionts. in this study, we use the recently identified ethylene-insensitive ein2 mutant in pea (pisum sativum l.) to explore the role of ethylene in the development of these symbioses. we show that ethylene acts as a strong negative regulator of nodulation, confirming reports in other legumes. minor changes in gibberellin1 and indole-3-acetic acid levels in ein2 ... | 2016 | 26889005 |
| using synthetic biology to increase nitrogenase activity. | nitrogen fixation has been established in protokaryotic model escherichia coli by transferring a minimal nif gene cluster composed of 9 genes (nifb, nifh, nifd, nifk, nife, nifn, nifx, hesa and nifv) from paenibacillus sp. wly78. however, the nitrogenase activity in the recombinant e. coli 78-7 is only 10 % of that observed in wild-type paenibacillus. thus, it is necessary to increase nitrogenase activity through synthetic biology. | 2016 | 26897628 |
| microevolution analysis of bacillus coahuilensis unveils differences in phosphorus acquisition strategies and their regulation. | bacterial genomes undergo numerous events of gene losses and gains that generate genome variability among strains of the same species (microevolution). our aim was to compare the genomes and relevant phenotypes of three bacillus coahuilensis strains from two oligotrophic hydrological systems in the cuatro ciénegas basin (méxico), to unveil the environmental challenges that this species cope with, and the microevolutionary differences in these genotypes. since the strains were isolated from a low ... | 2016 | 26903955 |
| draft genome sequence of sphingomonas paucimobilis strain lct-sp1 isolated from the shenzhou x spacecraft of china. | sphingomonas paucimobilis strain lct-sp1 is a glucose-nonfermenting gram-negative, chemoheterotrophic, strictly aerobic bacterium. the major feature of strain lct-sp1, isolated from the chinese spacecraft shenzhou x, together with the genome draft and annotation are described in this paper. the total size of strain lct-sp1 is 4,302,226 bp with 3,864 protein-coding and 50 rna genes. the information gained from its sequence is potentially relevant to the elucidation of microbially mediated corrosi ... | 2016 | 26918090 |
| genetic diversity of rhizobia nodulating native vicia spp. in sweden. | despite the recognition that rhizobium leguminosarum sv. viciae is the most common symbiont of vicia species worldwide, there is no available information on rhizobia nodulating native vicia species in sweden. we have therefore studied the genetic diversity and phylogeny of root nodule bacteria isolated from v. cracca, v. hirsuta, v. sepium, v. tetrasperma and v. sylvatica growing in different locations in sweden as well as an isolate each from v. cracca in tromsø, norway, and v. multicaulis in s ... | 2016 | 26924220 |
| broomrape weeds. underground mechanisms of parasitism and associated strategies for their control: a review. | broomrapes are plant-parasitic weeds which constitute one of the most difficult-to-control of all biotic constraints that affect crops in mediterranean, central and eastern europe, and asia. due to their physical and metabolic overlap with the crop, their underground parasitism, their achlorophyllous nature, and hardly destructible seed bank, broomrape weeds are usually not controlled by management strategies designed for non-parasitic weeds. instead, broomrapes are in current state of intensifi ... | 2016 | 26925071 |
| detection of hydrogen cyanide from oral anaerobes by cavity ring down spectroscopy. | hydrogen cyanide (hcn) has been recognized as a potential biomarker for non-invasive diagnosis of pseudomonas aeruginosa infection in the lung. however, the oral cavity is a dominant production site for exhaled hcn and this contribution can mask the hcn generated in the lung. it is thus important to understand the sources of hcn production in the oral cavity. by screening of oral anaerobes for hcn production, we observed that the genus of porphyromonas, prevotella and fusobacterium generated low ... | 2016 | 26940198 |
| [role of bacterial adhesin rapa1 in formation of efficient symbiosis of rhizobium leguminosarum with bean plants]. | bacterial adhesins, the proteins responsible for attachment of plant growth-promoting rhizobacteria to plant roots, are involved in formation of stable associative symbioses. in the present work enhanced expression of the rapa1 adhesin gene in rhizobium leguminosarum pvu5 was shown to improve the efficiency of nodulation on bean roots inoculated with the modified strain. the rapa1 gene was cloned into the pjn105turbo plasmid, this construct was used for transformation of r. leguminosarum pvu5, b ... | 2016 | 26964360 |
| a brazilian marseillevirus is the founding member of a lineage in family marseilleviridae. | in 2003, acanthamoeba polyphaga mimivirus (apmv) was discovered as parasitizing acanthamoeba. it was revealed to exhibit remarkable features, especially odd genomic characteristics, and founded viral family mimiviridae. subsequently, a second family of giant amoebal viruses was described, marseilleviridae, whose prototype member is marseillevirus, discovered in 2009. currently, the genomes of seven different members of this family have been fully sequenced. previous phylogenetic analysis suggest ... | 2016 | 26978387 |
| phylogenetic distribution and evolutionary pattern of an α-proteobacterial small rna gene that controls polyhydroxybutyrate accumulation in sinorhizobium meliloti. | it has become clear that srnas play relevant regulatory functions in bacteria. however, a comprehensive understanding of their biological roles considering evolutionary aspects has not been achieved for most of them. thus, we have characterized the evolutionary and phylogenetic aspects of the sinorhizobium meliloti mmgr gene encoding the small rna mmgr, which has been recently reported to be involved in the regulation of polyhydroxybutyrate accumulation in this bacterium. we constructed a covari ... | 2016 | 27033949 |
| cyanobacteria and eukaryotic algae use different chemical variants of vitamin b12. | eukaryotic microalgae and prokaryotic cyanobacteria are the major components of the phytoplankton. determining factors that govern growth of these primary producers, and how they interact, is therefore essential to understanding aquatic ecosystem productivity. over half of microalgal species representing marine and freshwater habitats require for growth the corrinoid cofactor b12, which is synthesized de novo only by certain prokaryotes, including the majority of cyanobacteria. there are several ... | 2016 | 27040778 |
| azospirillum brasilense chemotaxis depends on two signaling pathways regulating distinct motility parameters. | the genomes of most motile bacteria encode two or more chemotaxis (che) systems, but their functions have been characterized in only a few model systems. azospirillum brasilense is a motile soil alphaproteobacterium able to colonize the rhizosphere of cereals. in response to an attractant, motile a. brasilense cells transiently increase swimming speed and suppress reversals. the che1 chemotaxis pathway was previously shown to regulate changes in the swimming speed, but it has a minor role in che ... | 2016 | 27068592 |
| phylogenetic diversity of ammopiptanthus rhizobia and distribution of rhizobia associated with ammopiptanthus mongolicus in diverse regions of northwest china. | aiming to investigate the diversity and distribution of rhizobia associated with ammopiptanthus, an endangered evergreen legume widely distributed in deserts, we characterized a total of 219 nodule isolates from nine sampling sites in northwest china with different soil characteristics based upon restriction fragment length polymorphism (rflp) analysis of 16s ribosomal rna (rrna) and symbiotic genes (nodc and nifh). ten isolates representing different 16s rrna-rflp types were selected for furthe ... | 2016 | 27079453 |
| symbiotic nitrogen fixation and the challenges to its extension to nonlegumes. | access to fixed or available forms of nitrogen limits the productivity of crop plants and thus food production. nitrogenous fertilizer production currently represents a significant expense for the efficient growth of various crops in the developed world. there are significant potential gains to be had from reducing dependence on nitrogenous fertilizers in agriculture in the developed world and in developing countries, and there is significant interest in research on biological nitrogen fixation ... | 2016 | 27084023 |
| decoupled genomic elements and the evolution of partner quality in nitrogen-fixing rhizobia. | understanding how mutualisms evolve in response to a changing environment will be critical for predicting the long-term impacts of global changes, such as increased n (nitrogen) deposition. bacterial mutualists in particular might evolve quickly, thanks to short generation times and the potential for independent evolution of plasmids through recombination and/or hgt (horizontal gene transfer). in a previous work using the legume/rhizobia mutualism, we demonstrated that long-term nitrogen fertili ... | 2016 | 27087920 |
| exploring the secretomes of microbes and microbial communities using filamentous phage display. | microbial surface and secreted proteins (the secretome) contain a large number of proteins that interact with other microbes, host and/or environment. these proteins are exported by the coordinated activities of the protein secretion machinery present in the cell. a group of bacteriophage, called filamentous phage, have the ability to hijack bacterial protein secretion machinery in order to amplify and assemble via a secretion-like process. this ability has been harnessed in the use of filamento ... | 2016 | 27092113 |
| characterization and mutagenesis of two novel iron-sulphur cluster pentonate dehydratases. | we describe here the identification and characterization of two novel enzymes belonging to the ilvd/edd protein family, the d-xylonate dehydratase from caulobacter crescentus, cc xydht, (ec 4.2.1.82), and the l-arabonate dehydratase from rhizobium leguminosarum bv. trifolii, rl ardht (ec 4.2.1.25), that produce the corresponding 2-keto-3-deoxy-sugar acids. there is only a very limited amount of characterization data available on pentonate dehydratases, even though the enzymes from these oxidativ ... | 2016 | 27102126 |
| quorum-sensing synchronization of synthetic toggle switches: a design based on monotone dynamical systems theory. | synthetic constructs in biotechnology, biocomputing, and modern gene therapy interventions are often based on plasmids or transfected circuits which implement some form of "on-off" switch. for example, the expression of a protein used for therapeutic purposes might be triggered by the recognition of a specific combination of inducers (e.g., antigens), and memory of this event should be maintained across a cell population until a specific stimulus commands a coordinated shut-off. the robustness o ... | 2016 | 27128344 |
| from plant infectivity to growth patterns: the role of blue-light sensing in the prokaryotic world. | flavin-based photoreceptor proteins of the lov (light, oxygen, and voltage) and bluf (blue light sensing using flavins) superfamilies are ubiquitous among the three life domains and are essential blue-light sensing systems, not only in plants and algae, but also in prokaryotes. here we review their biological roles in the prokaryotic world and their evolution pathways. an unexpected large number of bacterial species possess flavin-based photosensors, amongst which are important human and plant p ... | 2014 | 27135492 |