| rumen fermentation and metabolic profile in conventional and gnotobiotic lambs. | observations were carried out of actual acidity, volatile fatty acid (vfa) concentrations, enzyme activity in the rumen, total protein, urea, total lipid and glucose in the serum of conventional (cl) and gnotobiotic lambs (gl) in the period of milk nutrition. the inoculum of gnotobiotic lambs contained streptococcus bovis, prevoxella ruminicola, butyrivibrio fibrisolvens and selenomonas ruminantium at a concentration of 1.10(6) each. throughout the observation period the ph of the rumen contents ... | 1995 | 8585797 |
| genetic transfer of lactate-utilizing ability in the rumen bacterium selenomonas ruminantium. | matings between the lactate-utilizing, tetracycline-sensitive selenomonas ruminantium strains 5521c1 and 5934e and the lactate-non-utilizing, tetracycline-resistant strain fb322 resulted in putative recombinant strains capable of growth on lactate. analysis of total protein by sds-page and chromosomal dna by hybridization, indicated that the recombinants were derived from strain fb322. dna hybridization produced no evidence that plasmid transfer occurred, leaving chromosomal dna transfer as the ... | 1996 | 8588888 |
| effect of extracellular hydrogen on organic acid utilization by the ruminal bacterium selenomonas ruminantium. | the objective of this study was to evaluate the effect of extracellular h2 on organic acid utilization by two lactate-utilizing strains of selenomonas ruminantium (hd4, h18). both strains were able to grow (optical density at 600 nm > or = after 9 h) on either aspartate, fumarate, or malate in the presence of 1 atmosphere (atm) of h2. succinate was the major end product produced in these fermentations. when cells were incubated with lactate plus 1 atm h2, growth was minimal little lactate was fe ... | 1996 | 8640106 |
| ecology, metabolism, and genetics of ruminal selenomonads. | selenomonas ruminantium is one of the more prominent and functionally diverse bacteria present in the rumen and can survive under a wide range of nutritional fluctuations. selenomonas is not a degrader of complex polysaccharides associated with dietary plant cell wall components, but is important in the utilization of soluble carbohydrates released from initial hydrolysis of these polymers by other ruminal bacteria. selenomonads have multiple carbon flow routes for carbohydrate catabolism and at ... | 1996 | 8729959 |
| hexose phosphorylation by the ruminal bacterium selenomonas ruminantium. | three strains of selenomonas ruminantium (d, ga192, and h18) were surveyed for phosphorylation of d-glucose and 2-deoxyglucose by phosphoenolpyruvate and atp. cells of all three strains that had been treated with toluene had high rates of hexose phosphorylation with either phosphoryl donor; this activity was constitutive in strain d. glucose phosphorylation that was dependent on phosphoenolpyruvate was maximal at ph 7.2, remained fairly high at ph 6.5, but decreased (> or = 65%) at ph 5.0 for al ... | 1996 | 8744219 |
| influence of calcium concentration on the antimicrobial activity of lasalocid against selenomonas ruminantium. | the present study was designed to examine the interaction between the effects of lasalocid and ca2+ on the growth and structure of selenomonas ruminantium hd-4. lasalocid, at a dose of 10 microm, inhibited cell growth almost completely after 12 hr incubation in the presence of relatively high extracellular concentrations of ca2+ (from 5 to 50 mm), but only slightly reduced cell growth in the presence of 0.2 mm ca2+. with ca2+ alone, cell growth was also inhibited at 12 hr as a function of the co ... | 1996 | 8877974 |
| use of fura-2/am to measure intracellular free calcium in selenomonas ruminantium. | this paper describes a procedure for loading the acetoxymethyl ester of fura-2 (fura-2/am), and the subsequent measurement of the concentration of intracellular free ca2+ ([ca2+]i) in selenomonas ruminantium (s. ruminantium) using this technique. to ascertain the optimal loading conditions, the effect was examined on the loading of fura-2/am of ethylenediamine-tetraacetic acid (edta), lysozyme, pluronic f127 alone, or the simultaneous application of edta and pluronic f127. individual administrat ... | 1996 | 8944431 |
| growth and fermentation responses of selenomonas ruminantium to limiting and non-limiting concentrations of ammonium chloride. | the objective of this study was to assess fermentation product, growth rate and growth yield responses of selenomonas ruminantium hd4 to limiting and non-limiting ammonia concentrations. the ammonia half-inhibition constant for s. ruminantium in batch culture was 296 mm. cells were grown in continuous culture with a defined ascorbate-reduced basal medium containing either 0.5, 5, 25, 50, 100 or 200 mm nh4cl and dilution rates were 0.07, 0.14, 0.24 or 0.40 h-1. ammonia was the growth-limiting nut ... | 1996 | 8987647 |
| the role of ciliate protozoa in the lysis of methanogenic archaea in rumen fluid. | predation by ciliate protozoa can account for 90% of the eubacterial protein turnover in the rumen. however, little is known about the factors affecting the lysis of archaea in rumen fluid. bacterial lysis was followed from the release of acid-soluble 14c from 14c leucine-labelled bacteria. the rumen methanogen methanobrevibacter mf1 was broken down more rapidly than other non-ruminal archaea in rumen fluid withdrawn from sheep harbouring either a mixed protozoa population or monofaunated with p ... | 1996 | 8987902 |
| malate content of forage varieties commonly fed to cattle. | the objective of this study was to determine the concentration of malate in forage varieties at different stages of maturity. five alfalfa varieties (alfagraze, apollo supreme cimarron, crockett, and magnum iii) and three bermudagrass varieties (coastal, tifton-78, and tifton-85) were collected at different stages of maturity. samples were collected from replicate plots (n = 3) of each alfalfa variety at 9, 18, 28, 35, and 42 d of maturity; bermudagrass hay samples were composited from six bales ... | 1997 | 9276804 |
| effects of a saccharomyces cerevisiae culture on ruminal bacteria that utilize lactate and digest cellulose. | the objective of this study was to determine the effects of a yeast (saccharomyces cerevisiae) culture on lactate utilization and cellulose digestion by ruminal bacteria. growth of selenomonas ruminantium hd4 in medium that contained 5 g/l of dl-lactate, trypticase, and yeast extract was stimulated 7 and 15% by 1 and 5% (vol/vol) yeast culture filtrate respectively. the 1 and 5% yeast culture filtrate stimulated growth of selenomonas ruminantium h18 and megasphaera elsdenii b159 and t81 on 5 g/l ... | 1997 | 9313145 |
| factors affecting lactate and malate utilization by selenomonas ruminantium. | lactate utilization by selenomonas ruminantium is stimulated in the presence of malate. because little information is available describing lactate-plus-malate utilization by this organism, the objective of this study was to evaluate factors affecting utilization of these two organic acids by two strains of s. ruminantium. when s. ruminantium hd4 and h18 were grown in batch culture on dl-lactate and dl-malate, both strains coutilized both organic acids for the initial 20 to 24 h of incubation and ... | 1997 | 9471965 |
| xylooligosaccharide utilization by the ruminal anaerobic bacterium selenomonas ruminantium. | fermentation of xylooligosaccharides by 11 strains of selenomonas ruminantium was examined. xylooligosaccharides were prepared by the partial hydrolysis of oat spelt xylan in dilute phosphoric acid (50 mm, 121 degrees c, 15 min) and were added to a complex, yeast extract-trypticase-containing medium. strains of s. ruminantium varied considerably in their capacity to ferment xylooligosaccharides. strains ga192, ga31, h18, and d used arabinose, xylose, and the oligosaccharides xylobiose through xy ... | 1998 | 9504982 |
| large plasmids in ruminal strains of selenomonas ruminantium. | the plasmid content of six different isolates of selenomonas ruminantium from the rumen of sheep, cows or goats was examined by electron microscopy. in addition to small plasmids (< 12 kb) studied previously, all six strains contained at least one plasmid larger than 20 kb. plasmid sizes of 1.4, 2.1, 2.4, 5.0, 6.2, 20.4, 20.8, 22.7, 23.3, 29.3, 30.7, 34.4 and 42.6 kb were estimated from contour length measurements. dna-dna hybridization experiments revealed homology among the large plasmids from ... | 1998 | 9633087 |
| phytase activity of anaerobic ruminal bacteria. | phytase catalyses the release of phosphate from phytate (myo-inositol hexakisphosphate), the predominant form of phosphorus in cereal grains, oilseeds and legumes. the presence of phytase activity was investigated in 334 strains of 22 species of obligately anaerobic ruminal bacteria. measurable activities were demonstrated in strains of selenomonas ruminantium, megasphaera elsdenii, prevotella ruminicola, mitsuokella multiacidus and treponema spp. strains isolated from fermentations with cereal ... | 1998 | 9639927 |
| effect of aspergillus oryzae extract alone or in combination with antimicrobial compounds on ruminal bacteria. | the effect of an aspergillus oryzae fermentation extract on the growth rates of pure cultures of ruminal bacteria was determined. bacteria were grown in an anaerobic ruminal fluid and carbohydrate medium. a sterile filtrate made with 10% a. oryzae was added to the medium at 2 or 5% (vol/vol) to provide a final a. oryzae concentration of 2 or 5 mg/ml, respectively. the filtrate had no effect on the growth rates of 10 of the 19 ruminal bacteria tested; however, the filtrate increased the growth ra ... | 1998 | 9684165 |
| de novo synthesis of amino acids by the ruminal bacteria prevotella bryantii b14, selenomonas ruminantium hd4, and streptococcus bovis es1. | the influence of peptides and amino acids on ammonia assimilation and de novo synthesis of amino acids by three predominant noncellulolytic species of ruminal bacteria, prevotella bryantii b14, selenomonas ruminantium hd4, and streptococcus bovis es1, was determined by growing these bacteria in media containing 15nh4cl and various additions of pancreatic hydrolysates of casein (peptides) or amino acids. the proportion of cell n and amino acids formed de novo decreased as the concentration of pep ... | 1998 | 9687438 |
| strategies that ruminal bacteria use to handle excess carbohydrate. | when ruminal bacteria have insufficient nitrogen and other nutrients, excess carbohydrate can be toxic. pure cultures that are nitrogen-limited can convert only some of the excess carbohydrate to intracellular polysaccharide, but this pool can be quickly saturated. fibrobacter succinogenes cultures that have excess cellobiose secrete glucose and cellotriose into the culture medium, and prevotella ruminicola produces methylglyoxal, a highly toxic substance that causes a dramatic decrease in viabi ... | 1998 | 9690652 |
| lysogenic bacteriophage m1 from selenomonas ruminantium: isolation, characterization and dna sequence analysis of the integration site. | bacteriophage m1 from the ruminal bacterium selenomonas ruminantium strain ml12 comprises a 30 nm icosahedral capsid, a 25 nm tail and 48 kb of linear dsdna with cohesive ends. a restriction map of the phage genome has been constructed. the presence of bacteriophage m1 in the rumen has been demonstrated by pcr amplification and southern blot analysis of dna from rumen bacterial samples obtained from ten different sheep. lysogeny was demonstrated by hybridization of m1 dna to host chromosomal dna ... | 1998 | 9720041 |
| selenomonas lipolytica sp. nov., an obligately anaerobic bacterium possessing lipolytic activity. | a novel, oligately anaerobic bacterium capable of hydrolysing lipids was isolated from a tropical anaerobic lagoon receiving waste water from an edible oil mill. the isolate had many characteristics similar to those of members of the genus selenomonas. the isolate showed lipolytic activity on tributyrin, triolein and groundnut oil in qualitative plate clearance assays, which has not been reported for the type strain of the genus selenomonas. it did not require n-valerate supplementation for grow ... | 1998 | 9734032 |
| two restriction endonucleases in selenomonas ruminantium subsp. lactilytica. | crude protein extract from a recently isolated ruminal bacterium identified as selenomonas ruminantium subsp. lactilytica specifically cleaved dna. this ability was due to the presence of two site-specific restriction endonucleases. sr/i, a naei schizomer, recognizes the 5'-gccggc-3' sequence. sr/ii, a nsii schizomer, recognizes 5'-atgcat-3'. | 1998 | 9750328 |
| detection of n6-methyladenine in gatc sequences of selenomonas ruminantium. | the presence of n6-methyladenine in gatc sequences in dna of selenomonas ruminantium was investigated using sensitive methylation discriminating isochizomeric restriction enzymes analysis. methylated adenine was detected in 8 out of 18 tested strains belonging to the subsp. lactilytica of s. ruminantium. no corresponding restriction activity was detected in three tested strains. no gatc methylation was detected in 3 analysed s. ruminantium subsp. ruminantium strains. sustainable progress was ach ... | 1998 | 9791949 |
| effects of laidlomycin propionate and monensin on glucose utilization and nutrient transport by streptococcus bovis and selenomonas ruminantium. | the objective of this study was to compare the effects of laidlomycin propionate and monensin on cell growth, glucose fermentation, and glucose uptake in streptococcus bovis strain jb1 and selenomonas ruminantium strain hd4. experiments were also conducted to compare the effects of both ionophores on sodium-dependent serine transport and cell yield in s. bovis. batch cultures (500 ml) of each bacterium were grown on 3.6 g/l d-glucose in semidefined medium and treated with either 5 ppm monensin o ... | 1998 | 9814916 |
| sequence analysis of small cryptic plasmids isolated from selenomonas ruminantium s20. | two small cryptic plasmids designated pone429 and pone430 were isolated from a rumen bacterium, selenomonas ruminantium s20. the complete sequence of pone429 was 2100 bp and contained one open reading frame (orf) of 201 amino acids. the sequence of pone430 had 1527 bp and one orf of 171 amino acids with the similarity of replication protein (rep protein) of pom1, psn2, and pim13 isolated from butyrivibrio fibrisolvens, staphylococcus aureus, and bacillus subtilis, respectively. in these plasmids ... | 1999 | 9871109 |
| manipulation of ruminal fermentation with organic acids: a review. | the dicarboxylic acids aspartate, fumarate, and malate stimulate lactate utilization by the predominant ruminal bacterium, selenomonas ruminantium. malate stimulates lactate uptake by s. ruminantium more than does aspartate or fumarate, and it seems that malate and sodium are involved in stimulating lactate utilization by this bacterium. based on the ability of s. ruminantium to grow on malate in the presence of extracellular hydrogen and produce succinate, malate may be acting as an electron si ... | 1998 | 9928618 |
| gc-ms analysis of diaminopimelic acid stereoisomers and amino acid enantiomers in rumen bacteria. | the amounts and the configuration of the stereoisomers of 2,6-diaminopimelic acid (dap) and the enantiomeric content of other amino acids were determined in five individual species (fibrobacter succinogenes, streptococcus bovis, selenomonas ruminantium, prevotella ruminicola and anaerovibrio lipolytica) of rumen bacteria, and in samples of mixed rumen bacteria isolated from sheep. the separation and quantification of the dap stereoisomers was achieved by gas chromatography (gc) of trifluoroacety ... | 1999 | 10191943 |
| effect of the addition of fumarate on methane production by ruminal microorganisms in vitro. | the effect of fumarate used as a feed additive on the reduction of methanogenesis in the rumen was evaluated by in vitro experiments. the addition of fumarate to the culture of mixed ruminal microorganisms that were fermenting hay powder and concentrate reduced methane production. most fumarate was metabolized to propionate, and a slight increase was noted in other volatile fatty acids. fumarate was utilized by mixed bacteria but not by mixed protozoa. fibrobacter succinogenes, selenomonas rumin ... | 1999 | 10212465 |
| complete nucleotide sequence of a cryptic plasmid from the ruminal bacterium selenomonas ruminantium hd4 and identification of two predicted open reading frames. | a cryptic plasmid (psr1) isolated from selenomonas ruminantium hd4 was previously cloned into the hindiii site of pbr322 and a restriction map was constructed using hindiii, clai, bamhi, and pvuii (s. a. martin and r. g. dean, appl. environ. microbiol. 55(12), 3035-3038, 1989). analysis of the nucleotide sequence of psr1 revealed two major open reading frames (orfs) located in the minus strand at different frames. analysis of orf-1 revealed that it has 325 amino acids with a predicted mw of 36,5 ... | 1999 | 10413665 |
| novel characteristics of selenomonas ruminantium lysine decarboxylase capable of decarboxylating both l-lysine and l-ornithine. | lysine decarboxylase (ldc; ec 4.1.1.18) of selenomonas ruminantium is a constitutive enzyme and is involved in the synthesis of cadaverine, which is an essential constituent of the peptidoglycan for normal cell growth. we purified the s. ruminantium ldc by an improved method including hydrophobic chromatography and studied the fine characteristics of the enzyme. kinetic study of ldc showed that s. ruminantium ldc decarboxylated both l-lysine and l-ornithine with similar km and the decarboxylase ... | 1999 | 10427692 |
| phylogenetic characterization of centipeda periodontii, selenomonas sputigena and selenomonas species by 16s rrna gene sequence analysis. | the nearly complete 16s rrna gene sequences for oral gram-negative anaerobic motile bacteria, centipeda periodontii, selenomonas sputigena and selenomonas species (formerly s. sputigena type strain), were determined in order to unveil their relationship to other oral motile bacteria. to determine the phylogenetic characterization of these bacteria, their 16s rrna gene sequences were obtained and compared with those from the ribosomal sequence databases previously reported. the 16s rrna gene sequ ... | 1999 | 10464949 |
| the ability of "low g + c gram-positive" ruminal bacteria to resist monensin and counteract potassium depletion. | gram-negative ruminal bacteria with an outer membrane are generally more resistant to the feed additive, monensin, than gram-positive species, but some bacteria can adapt and increase their resistance. 16s rrna sequencing indicates that a variety of ruminal bacteria are found in the "low g + c gram-positive group," but some of these bacteria are monensin resistant and were previously described as gram-negative species (e.g., selenomonas ruminantium and megasphaera elsdenii). the activity of mone ... | 1999 | 10486059 |
| identification of the amino acid residues conferring substrate specificity upon selenomonas ruminantium lysine decarboxylase. | lysine decarboxylase (ldc, ec 4.1.1.18) from selenomonas ruminantium has decarboxylating activities towards both l-lysine and l-ornithine with similar k(m) and vmax. here, we identified four amino acid residues that confer substrate specificity upon s. ruminantium ldc and that are located in its catalytic domain. we have succeeded in converting s. ruminantium ldc to an enzyme with a preference in decarboxylating activity for l-ornithine when the four-residue of ldc were replaced by the correspon ... | 1999 | 10586514 |
| characterization of a major envelope protein from the rumen anaerobe selenomonas ruminantium ob268. | cell envelopes from the gram-negative staining but phylogenetically gram-positive rumen anaerobe selenomonas ruminantium ob268 contained a major 42 kda heat modifiable protein. a similarly sized protein was present in the envelopes of selenomonas ruminantium d1 and selenomonas infelix. sodium dodecyl sulfate polyacrylamide gel electrophoresis of triton x-100 extracted cell envelopes from s. ruminantium ob268 showed that they consisted primarily of the 42 kda protein. polyclonal antisera produced ... | 2000 | 10779865 |
| localization of phytase in selenomonas ruminantium and mitsuokella multiacidus by transmission electron microscopy. | the localization of phytase (myo-inositol-hexaphosphate phosphohydrolase) in the ruminal bacteria, selenomonas ruminantium jy35 and mitsuokella multiacidus 46/5(2), was determined with transmission electron microscopy. phosphate produced from the enzymatic dephosphorylation of the calcium salt of phytic acid is precipitated as calcium phosphate. the calcium is then replaced with lead to produce electron-dense lead phosphate. this deposition of lead phosphate localized phytase in s. ruminantium j ... | 2000 | 10779878 |
| effect of steroidal saponin from yucca schidigera extract on ruminal microbes. | the effects of steroidal saponins (sap) isolated from yucca schidigera extract on ruminal bacteria and fungi were investigated in pure culture studies. prevotella bryantii, ruminobacter amylophilus, selenomonas ruminantium and streptococcus bovis were cultured through ten 24-h transfers in ruminal fluid medium containing 0 or 25 microg sap ml-1 (measured as smilagenin equivalents). the four strains, each non-exposed or pre-exposed to sap, were then inoculated into medium containing 0 or 250 micr ... | 2000 | 10792550 |
| highly conserved dna sequence present in small plasmids from selenomonas ruminantium. | plasmid pjw1 from selenomonas ruminantium subsp. lactilytica strain jw13 has been cloned in escherichia coli vector pbluescriptsk(-) and completely sequenced. the plasmid is only 1410 bp with an overall gc content of 42.2%. computer analysis of sequence data revealed a single open reading frame (orf1, 146 amino acids, mw 16,525.5 da) encoding a putative replication protein which is similar to the rep protein of ruminobacter amylophilus plasmid prao1. orf1 is followed by a long at-rich (75%) regi ... | 2000 | 10873531 |
| deoxyribonuclease activity in selenomonas ruminantium, streptococcus bovis, and bacteroides ovatus. | six selenomonas ruminantium strains (132c, jw13, srk1, 179f, 5521c1, and 5934e), streptococcus bovis jb1, and bacteroides ovatus v975 were examined for nuclease activity as well as the ability to utilize nucleic acids, ribose, and 2-deoxyribose. nuclease activity was detected in sonicated cells and culture supernatants for all bacteria except s. ruminantium jw13 and 179f sonicated cells. s. ruminantium strains were able to utilize several deoxyribonucleosides, while s. bovis jb1 and b. ovatus v9 ... | 2000 | 10915204 |
| effects of thymol on ruminal microorganisms. | thymol (5-methyl-2-isopropylphenol) is a phenolic compound that is used to inhibit oral bacteria. because little is known regarding the effects of this compound on ruminal microorganisms, the objective of this study was to determine the effects of thymol on growth and lactate production by the ruminal bacteria streptococcus bovis jb1 and selenomonas ruminantium hd4. in addition, the effect of thymol on the in vitro fermentation of glucose by mixed ruminal microorganisms was investigated. neither ... | 2000 | 11014870 |
| gene cloning and molecular characterization of lysine decarboxylase from selenomonas ruminantium delineate its evolutionary relationship to ornithine decarboxylases from eukaryotes. | lysine decarboxylase (ldc; ec 4.1.1.18) from selenomonas ruminantium comprises two identical monomeric subunits of 43 kda and has decarboxylating activities toward both l-lysine and l-ornithine with similar k(m) and v(max) values (y. takatsuka, m. onoda, t. sugiyama, k. muramoto, t. tomita, and y. kamio, biosci. biotechnol. biochem. 62:1063-1069, 1999). here, the ldc-encoding gene (ldc) of this bacterium was cloned and characterized. dna sequencing analysis revealed that the amino acid sequence ... | 2000 | 11073919 |
| effect of sugars and malate on ruminal microorganisms. | the objective of this study was to examine the effects of a commercial feed supplement that contains sugars and malate on lactate fermentation by selenomonas ruminantium grown in batch culture. experiments also were conducted to examine the effects of this feed supplement on the mixed ruminal microorganism fermentation of ground corn and soluble starch in the presence and absence of 5 mg/kg of monensin. when s. ruminantium strains hd4 and h18 were incubated in basal medium that contained dl-lact ... | 2000 | 11104277 |
| competition among three predominant ruminal cellulolytic bacteria in the absence or presence of non-cellulolytic bacteria. | competition among three species of ruminal cellulolytic bacteria - fibrobacter succinogenes s85, ruminococcus flavefaciens fd-1 and ruminococcus albus 7 - was studied in the presence or absence of the non-cellulolytic ruminal bacteria selenomonas ruminantium or streptococcus bovis. co-cultures were grown under either batch or continuous conditions and populations were estimated using species-specific oligonucleotide probes to 16s rrna. the three cellulolytic species co-existed in cellobiose batc ... | 2001 | 11160797 |
| evidence for recent intergeneric transfer of a new tetracycline resistance gene, tet(w), isolated from butyrivibrio fibrisolvens, and the occurrence of tet(o) in ruminal bacteria. | we have previously reported high-frequency transfer of tetracycline resistance between strains of the rumen anaerobic bacterium butyrivibrio fibrisolvens. donor strains were postulated to carry two tcr genes, one of which is transferred on a novel chromosomal element. it is shown here that coding sequences within the non-transmissible gene in b. fibrisolvens 1.230 are identical to those of the streptococcus pneumoniae tet(o) gene. this provides the first evidence for genetic exchange between fac ... | 1999 | 11207718 |
| molecular characterization, enzyme properties and transcriptional regulation of phosphoenolpyruvate carboxykinase and pyruvate kinase in a ruminal bacterium, selenomonas ruminantium. | to elucidate the regulatory mechanism for propionate production in selenomonas ruminantium, the molecular properties and gene expression of phosphoenolpyruvate carboxykinase (pck) and pyruvate kinase (pyk) were investigated. the pck was deduced to consist of 538 aa with a molecular mass of 59.6 kda, and appeared to exist as a monomer. the pyk was revealed to consist of four identical subunits consisting of 469 aa with a molecular mass of 51.3 kda. both mg(2+) and mn(2+) were required for the max ... | 2001 | 11238975 |
| diet-dependent shifts in the bacterial population of the rumen revealed with real-time pcr. | a set of pcr primers was designed and validated for specific detection and quantification of prevotella ruminicola, prevotella albensis, prevotella bryantii, fibrobacter succinogenes, selenomonas ruminantium-mitsuokella multiacida, streptococcus bovis, ruminococcus flavefaciens, ruminobacter amylophilus, eubacterium ruminantium, treponema bryantii, succinivibrio dextrinosolvens, and anaerovibrio lipolytica. by using these primers and the real-time pcr technique, the corresponding species in the ... | 2001 | 11375193 |
| restriction and modification systems of ruminal bacteria. | a high frequency of type ii restriction endonuclease activities was detected in selenomonas ruminantium but not in other rumen bacteria tested. eight different restriction endonucleases were characterized in 17 strains coming from genetically homogeneous local population. chromosomal dna isolated from s. ruminantium strains was found to be refractory to cleavage by various restriction enzymes, implying the presence of methylase activities additional to those required for protection against the c ... | 2001 | 11501482 |
| identification of a broad-specificity xylosidase/arabinosidase important for xylooligosaccharide fermentation by the ruminal anaerobe selenomonas ruminantium ga192. | strains of selenomonas ruminantium vary considerably in their capacity to ferment xylooligosaccharides. this ability ranges from strain ga192, which completely utilized xylose through xylotetraose and was able to ferment considerable quantities of larger oligosaccharides, to strain hd4, which used only the simple sugars present in the hydrolysate. the ability of s. ruminantium ga192 to utilize xylooligosaccharides was correlated with the presence of xylosidase and arabinosidase activities. the p ... | 2001 | 11683366 |
| a gene, coba + hemd, from selenomonas ruminantium encodes a bifunctional enzyme involved in the synthesis of vitamin b12. | coenzymes derived from vitamin b12 (cyanocobalamin) are particularly important for core metabolism in ruminant animals. selenomonas ruminantium, a gram-positive obligate anaerobe isolated from cattle, is the main contributor of vitamin b12 to such ruminant animals. in nature, there are both aerobic and anaerobic pathways for b12 synthesis - the latter is only partly elucidated. until now, there has been no investigation of b12 synthesis in s. ruminantium, which must use an anaerobic pathway. thi ... | 2001 | 11750128 |
| cloning of the l-lactate dehydrogenase gene from the ruminal bacterium selenomonas ruminantium hd4. | a clone from a selenomonas ruminantium hd4 lambda zap ii genomic library was isolated by its ability to complement the anaerobic growth deficiency of an escherichia coli (pfl, ldh) double mutant. the 1.0-kb insert from the clone was sequenced and revealed a single open reading frame (orf, 957-bp) which was preceded by a putative shine-dalgarno (sd) sequence (aggggg). the potential sd sequence corresponded to 3' 16s rrna sequences of various selenomonas strains. the orf was predicted to encode a ... | 2002 | 11821921 |
| cloning of the o-acetylserine lyase gene from the ruminal bacterium selenomonas ruminantium hd4. | the gene coding for o-acetylserine lyase (oasl) was cloned from a selenomonas ruminantium hd4 lambda zap ii genomic library by degenerative probe hybridization and complementation. sequence analysis revealed a 933 bp orf with a g + c content of 53%. the orf had significant homology with enzymes involved in cysteine biosynthesis. a curablastn homology search showed that the orf shared 59% nucleotide identity with the cysk of bacillus subtilis. the deduced amino acid sequence exhibited high (>70%) ... | 2002 | 11821922 |
| plasmids of selenomonas ruminantium and development of host-vector system. | a high frequency of plasmids was detected in the rumen bacterium selenomonas ruminantium. plasmids 0.9-20 kb in size were detected in more than 50% tested strains. densitometric analysis indicated that plasmid dna could represents more than 25% of total cellular dna. up to six plasmids were detected in strain s. ruminantium 18. two smallest cryptic plasmids psrd181 and psrd182 from this strain were cloned into escherichia coli vector pbluescriptsk+ and partially characterized. the plasmid psrd18 ... | 2001 | 11830938 |
| a flavoprotein encoded in selenomonas ruminantium is characterized after expression in escherichia coli. | selenomonas ruminantium is an obligate anaerobe that is very important for the provision of vitamin b12 to ruminants, which are particularly dependent upon this cofactor. one important use for vitamin b12 in anaerobic bacteria is for the utilization of glycerol as carbon source. a new flavoprotein has been found expressed by escherichia coli from a plasmid created as part of a gene library of s. ruminantium. the 2.5-kb fragment of chromosomal dna responsible for protein expression contains parts ... | 2002 | 11922759 |
| identification of a 22-kda protein required for the degradation of selenomonas ruminantium lysine decarboxylase by atp-dependent protease. | in selenomonas ruminantium, a strictly anaerobic, gram-negative bacterium isolated from sheep rumen, a rapid degradation of lysine decarboxylase (ldc) occurred on entry into the stationary phase of cell growth. here, we identified a 22-kda protein as a stimulating factor for the degradation of ldc, which was catalyzed by atp-dependent protease(s) in s. ruminantium. the purified 22-kda protein preparation itself had no degradation activity towards ldc but it was required for the degradation of ld ... | 2002 | 12162576 |
| activity and properties of fumarate reductase in ruminal bacteria. | fumarate-reducing bacteria were sought from the main ruminal bacteria. fibrobacter succinogenes, selenomonas ruminantium subsp. ruminantium, selenomonas ruminantium subsp. lactilytica, and veillonella parvula reduced fumarate by using h(2) as an electron donor. ruminococcus albus, prevotella ruminicola, and anaerovibrio lipolytica consumed fumarate, although they did not oxidize h(2). of these bacteria, v. parvula, two strains of selenomonas, and f. succinogenes had a high capacity to reduce fum ... | 2000 | 12483585 |
| diet influences the ecology of lactic acid bacteria and escherichia coli along the digestive tract of cattle: neural networks and 16s rdna. | in this manuscript, the authors have sought to gain a better understanding of the interactions between escherichia coli and lactic acid bacteria (lab) isolated from rogossa mrs agar along the digestive tract of grain- and forage-fed cattle. e. coli from cattle receiving a high-grain diet were more numerous (p<0.05) than from the high-forage diet and the highest numbers were in the faeces. isolates on rogossa mrs agar were always greater in the high-grain diet (p<0.05) and contained a significant ... | 2003 | 12576580 |
| allisonella histaminiformans gen. nov., sp. nov. a novel bacterium that produces histamine, utilizes histidine as its sole energy source, and could play a role in bovine and equine laminitis. | when cattle and horses are fed large amounts of grain, histamine can accumulate in the gastrointestinal tract, and this accumulation can cause an acute inflammation of the hooves (laminitis). when ruminal fluid from dairy cattle fed grain supplements was serially diluted in anaerobic mrs medium containing histidine (50 mm), histamine was detected at dilutions as high as 10(-7). the histidine enrichments were then transferred successively in an anaerobic, carbonate-based medium (50 mm histidine) ... | 2002 | 12583709 |
| growth factors for selenomonas ruminantium. | | 1963 | 13954887 |
| isolation, enumeration, and characteristics of proteolytic ruminal bacteria. | fulghum, robert s. (virginia polytechnic institute, blacksburg) and w. e. c. moore. isolation, enumeration, and characteristics of proteolytic ruminal bacteria. j. bacteriol. 85:808-815. 1963.-colony counts of proteolytic ruminal bacteria in the order of 10(9) organisms per g of whole rumen contents, and total colony counts in the order of 2 to 3 x 10(9) organisms per g, were obtained from rumen contents of cattle fed a maintenance ration of hay and grain. the proteolytic counts averaged 38% of ... | 1963 | 14044947 |
| molecular dissection of the selenomonas ruminantium cell envelope and lysine decarboxylase involved in the biosynthesis of a polyamine covalently linked to the cell wall peptidoglycan layer. | the wild type of selenomonas ruminantium subsp. lactilytica, which is a strictly anaerobic, gram-negative bacterium isolated from sheep rumen, requires one of the normal saturated volatile fatty acids with 3 to 10 carbon atoms for its growth in a glucose medium; however, no such obligate requirement of fatty acid is observed when the cells are grown in a lactate medium. this bacterium is characterized by a unique structure of the cell envelope and a novel lysine decarboxylase and its regulatory ... | 2004 | 14745158 |
| cloning of the o-acetylhomoserine sulfhydrylase gene from the ruminal bacterium selenomonas ruminantium hd4. | the o-acetylhomoserine sulfhydrylase (oahs) gene was cloned from a selenomonas ruminantium hd4 lambda zap ii genomic library by degenerative probe hybridization and complementation. sequence analysis revealed an 869-bp orf with a g + c content of 53%. the orf had significant homology with enzymes involved in homocysteine biosynthesis. a curablastn homology search showed that the orf has 63% nucleotide identity with the oahs of bacillus stearothermophilus, corynebacterium glutamicum, and acremoni ... | 2004 | 15057458 |
| production of two highly active bacterial phytases with broad ph optima in germinated transgenic rice seeds. | phytate is the main storage form of phosphorus in many plant seeds, but phosphate bound in this form is not available to monogastric animals. phytase, an enzyme that hydrolyzes phosphate from phytate, has the potential to enhance phosphorus availability in animal diets when engineered in rice seeds as a feed additive. two genes, derived from a ruminal bacterium selenomonas ruminantium (srpf6) and escherichia coli (appa), encoding highly active phytases were expressed in germinated transgenic ric ... | 2004 | 15070073 |
| specific pcr assay for a tannin-tolerant selenomonas ruminantium isolate, derived from helicase coding sequences. | sequences from a tannin-tolerant selenomonas ruminantium isolate (eat2) that hydrolyzes gallic acid were identified. two exhibited identity to helicases with a wide phylogenetic distribution. pcr amplification by using primers from one helicase gene detected 2000 to 5000 eat2 genome equivalents but did not amplify total gastrointestinal microbial dna of nine other ungulate species. | 2004 | 15128588 |
| different restriction and modification phenotypes in ruminal lactate-utilizing bacteria. | analysis of restriction and modification activities in lactate-utilizing bacteria belonging to the megasphaera elsdenii and mitsuokella multiacida species revealed the presence of gatc-specific, mboi isospecific, restriction-modification (r-m) systems in all strains tested. while restriction endonucleases isolated from m. elsdenii strains were found to be sensitive to dam methylation, enzymes from m. multiacida cleaved dna irrespective of dam methylation. the comparison of type ii r-m systems sp ... | 2004 | 15212796 |
| molecular characterization and transcriptional regulation of nitrate reductase in a ruminal bacterium, selenomonas ruminantium. | nitrate reductase (nar) of a strain of selenomonas ruminantium was purified, and the gene encoding nar (nar) was sequenced. the 6.4 kbp nar gene consisted of narg, h, j, and i in this order. the deduced amino acid sequences of these subunits resembled those of membrane-bound nitrate reductase-a reported for escherichia coli. it was shown that narg, h, j, and i are transcribed as a single polycistronic message (nar operon). the level of intracellular nar-mrna was higher when s. ruminantium was gr ... | 2004 | 15248143 |
| protozoa involved in butyric rather than lactic fermentative pattern during latent acidosis in sheep. | we used six ruminally cannulated texel wethers to study the relative role of protozoa and lactate-metabolizing bacteria in ruminal fermentative patterns during an induced latent acidosis. the sheep were fed an alfalfa hay diet (h) and latent acidosis was induced, following a short transition period of one week, with a grain-rich acidotic diet (w, 60% wheat + 40% alfalfa hay). ruminal ph, ruminal volatile fatty acids (vfa), lactate and nh3 concentrations, protozoa and lactate-utilizing bacterial ... | 2004 | 15460159 |
| structures of selenomonas ruminantium phytase in complex with persulfated phytate: dsp phytase fold and mechanism for sequential substrate hydrolysis. | various inositide phosphatases participate in the regulation of inositol polyphosphate signaling molecules. plant phytases are phosphatases that hydrolyze phytate to less-phosphorylated myo-inositol derivatives and phosphate. the phytase from selenomonas ruminantium shares no sequence homology with other microbial phytases. its crystal structure revealed a phytase fold of the dual-specificity phosphatase type. the active site is located near a conserved cysteine-containing (cys241) p loop. we al ... | 2004 | 15530366 |
| psrd191, a new member of repl replicating plasmid family from selenomonas ruminantium. | a numerous plasmid population was detected in strain 19 of selenomonas ruminantium. the population was found to consist of six plasmids in size ranging from 1.4 to more than 20kb. the smallest 1.4kb cryptic plasmid psrd191 was further characterized. sequence analysis identified a single orf encoding the 177-residue putative replication protein (rep191) which shared significant homology with repl family of replication protein from firmicutes (staphylococci and bacilli). pcr analysis and southern ... | 2005 | 15907537 |
| underrepresentation of short palindromes in selenomonas ruminantium dna: evidence for horizontal gene transfer of restriction and modification systems? | molecular analysis of isolates of the rumen bacterium selenomonas ruminantium revealed a high variety and frequency of site-specific (restriction) endonucleases. while all known s. ruminantium restriction and modification systems recognize hexanucleotide sequences only, consistently low counts of both 6-bp and 4-bp palindromes were found in dna sequences of s. ruminantium. statistical analysis indicated that there is some correlation between the degree of underrepresentation of tetranucleotide w ... | 2005 | 15980893 |
| interaction of gut microflora with tannins in feeds. | tannins (hydrolyzable and condensed) are water-soluble polyphenolic compounds that exert antinutritional effects on ruminants by forming complexes with dietary proteins. they limit nitrogen supply to animals, besides inhibiting the growth and activity of ruminal microflora. however, some gastrointestinal microbes are able to break tannin-protein complexes while preferentially degrading hydrolyzable tannins (hts). streptococcus gallolyticus, lonepinella koalarum and selenomonas ruminantium are th ... | 2005 | 16193308 |
| nutritional requirements of selenomonas ruminantium for growth on lactate, glycerol, or glucose. | the nutritional requirements of selenomonas ruminantium hd4 for growth on glucose, glycerol, or lactate were investigated to clarify the results of previous studies and to relate the nutrition of the organism to its physiology. the organism required l-aspartate, co(2), p-aminobenzoic acid, and biotin for growth on a lactate-salts medium that contained small amounts of dithiothreitol. aspartate could be replaced by l-malate or fumarate but not by succinate or l-asparagine. requirements for growth ... | 1978 | 16345271 |
| comparison of substrate affinities among several rumen bacteria: a possible determinant of rumen bacterial competition. | five rumen bacteria, selenomonas ruminantium, bacteroides ruminicola, megasphaera elsdenii, streptococcus bovis, and butyrivibrio fibrisolvens were grown in continuous culture. estimates of substrate affinities were derived from lineweaver-burk plots of dilution rate versus substrate concentration. each bacterium was grown on at least four of the six substrates: glucose, maltose, sucrose, cellobiose, xylose, and lactate. wide variations in substrate affinities were seen among the substrates util ... | 1979 | 16345358 |
| comparison of maintenance energy expenditures and growth yields among several rumen bacteria grown on continuous culture. | maintenance energy expenditures were mesured for five rumen bacteria, selenomonas ruminantium, butyrivibrio fibrisolvens, bacteroides ruminicola, megasphaera elsdenii, and streptococcus bovis, by using a complex medium with glucose as the carbon source. large differences (as high as 8.5-fold) in maintenance energy expenditures were seen among these bacteria. the suggestion is made that maintenance requirements could be a significant determinant of bacterial competition in the rumen. theoretical ... | 1979 | 16345359 |
| effects of combinations of substrates on maximum growth rates of several rumen bacteria. | five rumen bacteria, selenomonas ruminantium, bacteroides ruminicola, megasphaera elsdenii, butyrivibrio fibrisolvens, and streptococcus bovis were grown in media containing nonlimiting concentrations of glucose, sucrose, maltose, cellobiose, xylose and/or lactate. each bacterium was grown with every substrate that it could ferment in every possible two-way combination. only once did a combination of substrates result in a higher maximum growth rate than that observed with either substrate alone ... | 1979 | 16345360 |
| effect of monensin and lasalocid-sodium on the growth of methanogenic and rumen saccharolytic bacteria. | it is thought that monensin increases the efficiency of feed utilization by cattle by altering the rumen fermentation. we studied the effect of monensin and the related ionophore antibiotic lasalocid-sodium (hoffman-laroche) on the growth of methanogenic and rumen saccharolytic bacteria in a complex medium containing rumen fluid. ruminococcus albus, ruminococcus flavefaciens, and butyrivibrio fibrisolvens were inhibited by 2.5 mug of monensin or lasalocid per ml. growth of bacteroides succinogen ... | 1979 | 16345418 |
| effects of long-chain fatty acids on growth of rumen bacteria. | the effects of low concentrations of long-chain fatty acids (palmitic, stearic, oleic, and vaccenic) on the growth of seven species (13 strains) of rumen bacteria were investigated. except for bacteroides ruminicola and several strains of butyrivibrio fibrisolvens, bacterial growth was not greatly affected by either palmitic or stearic acids. in contrast, growth of selenomonas ruminantium, b. ruminicola, and one strain of b. fibrisolvens was stimulated by oleic acid, whereas the cellulolytic spe ... | 1981 | 16345887 |
| changes in viability, cell composition, and enzyme levels during starvation of continuously cultured (ammonia-limited) selenomonas ruminantium. | under nitrogen (ammonia)-limited continuous culture conditions, the ruminal anaerobe selenomonas ruminantium was grown at various dilution rates (d). the proportion of the population that was viable increased with d, being 91% at d = 0.5 h. washed cell suspensions were subjected to long-term nutrient starvation at 39 degrees c. all populations exhibited logarithmic linear declines in viability that were related to the growth rate. cells grown at d = 0.05, 0.20, and 0.50 lost about 50% viability ... | 1982 | 16346116 |
| enrichment and isolation of rumen bacteria that reduce trans- aconitic acid to tricarballylic acid. | bacteria from the bovine rumen capable of reducing trans-aconitate to tricarballylate were enriched in an anaerobic chemostat containing rumen fluid medium and aconitate. after 9 days at a dilution rate of 0.07 h, the medium was diluted and plated in an anaerobic glove box. three types of isolates were obtained from the plates (a crescent-shaped organism, a pleomorphic rod, and a spiral-shaped organism), and all three produced tricarballylate in batch cultures that contained glucose and trans-ac ... | 1985 | 16346691 |
| adhesion of cellulolytic ruminal bacteria to barley straw. | adhesion of the cellulolytic ruminal bacteria ruminococcus flavefaciens and fibrobacter succinogenes to barley straw was measured by incubating bacterial suspensions with hammer-milled straw for 30 min, filtering the mixtures through sintered glass filters, and measuring the optical densities of the filtrates. maximum adhesion of both species occurred at ph 6.0 and during mid- to late-exponential phase. adhesion was saturable at 33 and 23 mg (dry weight) g of straw for r. flavefaciens and f. suc ... | 1990 | 16348278 |
| characterization of egg yolk antibodies for detection and quantification of selenomonas ruminantium by using an enzyme-linked immunosorbent assay. | the specificity of polyclonal antibodies prepared against strains of selenomonas ruminantium, the effect of assay conditions, and quantification of individual strains in mixed-cell suspensions of selenomonad strains were examined in this study. whole-cell suspensions were prepared with pure cultures of s. ruminantium pc18, hd(4), ga192, and d. each cell suspension was injected into a leghorn laying hen, and polyclonal antibodies were harvested from eggs laid in week 3 or 7 following initial immu ... | 1990 | 16348287 |
| effect of dicarboxylic acids and aspergillus oryzae fermentation extract on lactate uptake by the ruminal bacterium selenomonas ruminantium. | the objective of this study was to determine the effects of l-aspartate, fumarate, l-malate, and an aspergillus oryzae fermentation extract (amaferm) on growth on lactate as well as lactate uptake by selenomonas ruminantium hd4. growth of s. ruminantium in medium that contained 2 g of dl-lactate per liter was stimulated approximately twofold by 10 mm l-aspartate, fumarate, or l-malate after 24 h. both l-aspartate and fumarate increased lactate uptake over 4-fold, while l-malate stimulated uptake ... | 1990 | 16348354 |
| characterization of a counterpart to mammalian ornithine decarboxylase antizyme in prokaryotes. | the degradation of mammalian ornithine decarboxylase (odc) (ec 4.1.1.17) by 26 s proteasome, is accelerated by the odc antizyme (az), a trigger protein involved in the specific degradation of eukaryotic odc. in prokaryotes, az has not been found. previously, we found that in selenomonas ruminantium, a strictly anaerobic and gram-negative bacterium, a drastic degradation of lysine decarboxylase (ldc; ec 4.1.1.18), which has decarboxylase activities toward both l-lysine and l-ornithine with simila ... | 2006 | 16354653 |
| characterization of tannin acylhydrolase activity in the ruminal bacterium selenomonas ruminantium. | a strain of the anaerobe selenomonas ruminantium subsp. ruminantium that is capable of growing on tannic acid or condensed tannin as a sole energy source has been isolated from ruminal contents of feral goats browsing tannin-rich acacia sp. growth on tannic acid was accompanied by release of gallic acid into the culture medium but the bacterium was incapable of using gallic acid as a sole energy source. tannin acylhydrolase (ec 3.1.1.20) activity was measured in crude cell-free extracts of the b ... | 1995 | 16887543 |
| prevalence of ctgcag recognizing restriction and modification systems in ruminal selenomonades. | analysis of restriction and modification activities in natural population of selenomonas ruminantium have revealed the prevalence of ctgcag (pst i isoschizomers) recognizing restriction and/or modification systems in these bacteria. pst i isoschizomeric restriction endonucleases were detected in 4 out of 15 strains tested. in one strain, the pst i isoschizomeric restriction system was accompanied by another restriction and modification system recognizing gaattc sequence (eco ri isoschizomer). fo ... | 1999 | 16887660 |
| spreading and mutability of selenomonas ruminantium plasmids. | two small plasmids from selenomonas ruminantium strain 19d were cloned in escherichia coli and completely characterized. sequence comparison indicated that the plasmids are similar to those reported in genetically vaguely related s. ruminantium strain s20. small 1.4-kb plasmids psrd191 and pone430 are only distantly related (approximately 30 % for deduced rep protein amino acid sequence) but possess a short highly conserved region outside rep gene. larger plasmids psrd192 and pone429 possess lar ... | 2006 | 17007426 |
| dominance of prevotella and low abundance of classical ruminal bacterial species in the bovine rumen revealed by relative quantification real-time pcr. | relative quantification real-time pcr was used to quantify several bacterial species in ruminal samples from two lactating cows, each sampled 3 h after feeding on two successive days. abundance of each target taxon was calculated as a fraction of the total 16s rrna gene copies in the samples, using taxon-specific and eubacterial domain-level primers. bacterial populations showed a clear predominance of members of the genus prevotella, which comprised 42% to 60% of the bacterial rrna gene copies ... | 2007 | 17235560 |
| kinetic and structural analysis of a bacterial protein tyrosine phosphatase-like myo-inositol polyphosphatase. | phya from selenomonas ruminantium (phyasr), is a bacterial protein tyrosine phosphatase (ptp)-like inositol polyphosphate phosphatase (ippase) that is distantly related to known ptps. phyasr has a second substrate binding site referred to as a standby site and the p-loop (hcx5r) has been observed in both open (inactive) and closed (active) conformations. site-directed mutagenesis and kinetic and structural studies indicate phyasr follows a classical ptp mechanism of hydrolysis and has a broad sp ... | 2007 | 17567745 |
| inhibition of the two-subsite beta-d-xylosidase from selenomonas ruminantium by sugars: competitive, noncompetitive, double binding, and slow binding modes. | the active site of the gh43 beta-xylosidase from selenomonas ruminantium comprises two subsites and a single access route for ligands. steady-state kinetic experiments that included enzyme (e), inhibitory sugars (i and x) and substrate (s) establish examples of ei, eii, eix, and eis complexes. protonation states of catalytic base (d14, pk(a) 5) and catalytic acid (e186, pk(a) 7) govern formation of inhibitor complexes and strength of binding constants: e.g., eii, eix, and eis occur only with the ... | 2007 | 17588525 |
| structure-function relationships of a catalytically efficient beta-d-xylosidase. | beta-d-xylosidase from selenomonas ruminantium is revealed as the best catalyst known (kcat, kcat/km) for promoting hydrolysis of 1,4-beta-d-xylooligosaccharides. 1h nuclear magnetic resonance experiments indicate the family 43 glycoside hydrolase acts through an inversion mechanism on substrates 4-nitrophenyl- beta-d-xylopyranoside (4npx) and 1,4-beta-d-xylobiose (x2). progress curves of 4-nitrophenyl-beta-d-xylobioside, xylotetraose and xylohexaose reactions indicate that one residue from the ... | 2007 | 17625266 |
| variation in relative substrate specificity of bifunctional beta-d-xylosidase/alpha-l-arabinofuranosidase by single-site mutations: roles of substrate distortion and recognition. | to probe differential control of substrate specificities for 4-nitrophenyl-alpha-l-arabinofuranoside (4npa) and 4-nitrophenyl-beta-d-xylopyranoside (4npx), residues of the glycone binding pocket of gh43 beta-d-xylosidase/alpha-l-arabinofuranosidase from selenomonas ruminantium were individually mutated to alanine. although their individual substrate specificities (kcat/km)(4npx) and (kcat/km)(4npa) are lowered 330 to 280,000 fold, d14a, d127a, w73a, e186a, and h248a mutations maintain similar re ... | 2007 | 17689155 |
| two segments in bacterial antizyme p22 are essential for binding and enhance degradation of lysine/ornithine decarboxylase in selenomonas ruminantium. | in selenomonas ruminantium, a strictly anaerobic and gram-negative bacterium, the degradation of lysine/ornithine decarboxylase (ldc/odc) by atp-requiring protease(s) is accelerated by the binding of p22, which is a ribosomal protein of this strain. amino acid sequence alignment of s. ruminantium p22 with the l10 ribosomal proteins of gram-positive and -negative bacteria showed that p22 has a 5-residue k101nkld105 segment and an 11-residue g160virnavyvld170 segment, both of which are lacking in ... | 2008 | 17965150 |
| the characterization of lactic acid producing bacteria from the rumen of dairy cattle grazing on improved pasture supplemented with wheat and barley grain. | to identify and characterize the major lactic acid bacteria in the rumen of dairy cattle grazing improved pasture of rye grass and white clover and receiving a maize silage and grain supplement with and without virginiamycin. | 2008 | 18217928 |
| occurrence of agmatine pathway for putrescine synthesis in selenomonas ruminatium. | selenomonas ruminantium synthesizes cadaverine and putrescine from l-lysine and l-ornithine as the essential constituents of its peptidoglycan by a constitutive lysine/ornithine decarboxylase (ldc/odc). s. ruminantium grew normally in the presence of the specific inhibitor for ldc/odc, dl-alpha-difluoromethylornithine, when arginine was supplied in the medium. in this study, we discovered the presence of arginine decarboxylase (adc), the key enzyme in agmatine pathway for putrescine synthesis, i ... | 2008 | 18256468 |
| a protein tyrosine phosphatase-like inositol polyphosphatase from selenomonas ruminantium subsp. lactilytica has specificity for the 5-phosphate of myo-inositol hexakisphosphate. | although it is becoming well known that myo-inositol polyphosphates and the enzymes involved in their metabolism play a critical role in eukaryotic systems, little is understood of their significance in prokaryotic systems. a novel protein tyrosine phosphatase (ptp)-like inositol polyphosphatase (ippase) gene has been cloned from selenomonas ruminantium subsp. lactilytica (phyasrl). the deduced amino acid sequence of phyasrl is most similar to a ptp-like ippase from the anaerobic bacterium s. ru ... | 2008 | 18358762 |
| structure of the two-subsite beta-d-xylosidase from selenomonas ruminantium in complex with 1,3-bis[tris(hydroxymethyl)methylamino]propane. | the three-dimensional structure of the catalytically efficient beta-xylosidase from selenomonas ruminantium in complex with competitive inhibitor 1,3-bis[tris(hydroxymethyl)methylamino]propane (btp) was determined by using x-ray crystallography (1.3a resolution). most h bonds between inhibitor and protein occur within subsite -1, including one between the carboxyl group of e186 and an n group of btp. the other n of btp occupies subsite +1 near k99. e186 (pk(a) 7.2) serves as catalytic acid. the ... | 2008 | 18374656 |
| beta-d-xylosidase from selenomonas ruminantium: catalyzed reactions with natural and artificial substrates. | catalytically efficient beta-d-xylosidase from selenomonas ruminantium (sxa) exhibits pk (a)s 5 and 7 (assigned to catalytic base, d14, and catalytic acid, e186) for k (cat)/k (m) with substrates 1,4-beta-d-xylobiose (x2) and 1,4-beta-d-xylotriose (x3). catalytically inactive, dianionic sxa (d14(-)e186(-)) has threefold lower affinity than catalytically active, monoanionic sxa (d14(-)e186(h)) for x2 and x3, whereas d14(-)e186(-) has twofold higher affinity than d14(-)e186(h) for 4-nitrophenyl-be ... | 2008 | 18421594 |
| beta-d-xylosidase from selenomonas ruminantium of glycoside hydrolase family 43. | beta-d-xylosidase from the ruminal anaerobic bacterium, selenomonas ruminantium (sxa), catalyzes hydrolysis of beta-1,4-xylooligosacharides and has potential utility in saccharification processes. the enzyme, heterologously produced in escherichia coli and purified to homogeneity, has an isoelectric point of approx 4.4, an intact n terminus, and a stokes radius that defines a homotetramer. sxa denatures between ph 4.0 and 4.3 at 25 degrees c and between 50 and 60 degrees c at ph 5.3. following h ... | 2007 | 18478379 |
| effect of ionic strength and oxidation on the p-loop conformation of the protein tyrosine phosphatase-like phytase, phyasr. | the protein tyrosine phosphatase (ptp)-like phytase, phyasr, from selenomonas ruminantium is a novel member of the ptp superfamily, and the only described member that hydrolyzes myo-inositol-1,2,3,4,5,6-hexakisphosphate. in addition to the unique substrate specificity of phyasr, the phosphate-binding loop (p-loop) has been reported to undergo a conformational change from an open (inactive) to a closed (active) conformation upon ligand binding at low ionic strength. at high ionic strengths, the p ... | 2008 | 18573100 |
| necessary corrections to the approved lists of bacterial names according to rule 40d (formerly rule 46). opinion 86. | the judicial commission affirms that, according to rule 40d, formerly rule 46, of the bacteriological code, the authorship of a number of subspecies names included on the approved lists of bacterial names must be corrected. these names are acetobacter aceti subsp. aceti, acetobacter pasteurianus subsp. pasteurianus, bacteroides melaninogenicus subsp. melaninogenicus, campylobacter fetus subsp. fetus, mycobacterium chelonae subsp. chelonae, propionibacterium freudenreichii subsp. freudenreichii, ... | 2008 | 18676492 |
| genetic variability of rumen selenomonads. | molecular diversity of rumen bacteria belonging to the species selenomonas ruminantium was evaluated by biochemical and pcr analyses targeted at the 16s rrna operon and lactate dehydrogenase gene. while extremely variable in metabolic characteristics, two different risa (ribosomal intergenic spacer analysis), and five lactate dehydrogenase gene rflp profiles were observed among the twelve strains studied. the strains showed very limited variability ardra ( amplified ribosomal dna restriction ana ... | 2008 | 18837167 |
| biotransformation of 2,4,6-trinitrotoluene by pure culture ruminal bacteria. | twenty-one ruminal bacteria species were tested for their ability to degrade 2,4,6-trinitrotoluene (tnt) within 24 h. butyrivibrio fibrisolvens, fibrobacter succinogenes, lactobacillus vitulinus, selenomonas ruminantium, streptococcus caprinus, and succinivibrio dextrinosolvens were able to completely degrade 100 mg/l tnt, with <5% of the original tnt recovered as diaminonitrotoluene metabolites. eubacterium ruminantium, lactobacillus ruminis, ruminobacter amylophilus, streptococcus bovis, and w ... | 2009 | 18839246 |
| beta-d-xylosidase from selenomonas ruminantium: thermodynamics of enzyme-catalyzed and noncatalyzed reactions. | beta-d-xylosidase/alpha-l-arabinofuranosidase from selenomonas ruminantium is the most active enzyme known for catalyzing hydrolysis of 1,4-beta-d: -xylooligosaccharides to d-xylose. temperature dependence for hydrolysis of 4-nitrophenyl-beta-d-xylopyranoside (4npx), 4-nitrophenyl-alpha-l-arabinofuranoside (4npa), and 1,4-beta-d-xylobiose (x2) was determined on and off (k (non)) the enzyme at ph 5.3, which lies in the ph-independent region for k (cat) and k (non). rate enhancements (k (cat)/k (n ... | 2009 | 18953511 |