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1.
J Struct Biol ; 215(4): 108039, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37884067

RESUMEN

In this work, we investigated the lactate dehydrogenase (LDH) from Selenomonas ruminantium (S. rum), an enzyme that differs at key amino acid positions from canonical allosteric LDHs. The wild type (Wt) of this enzyme recognises pyuvate as all LDHs. However, introducing a single point mutation in the active site loop (I85R) allows S. Rum LDH to recognize the oxaloacetate substrate as a typical malate dehydrogenase (MalDH), whilst maintaining homotropic activation as an LDH. We report the tertiary structure of the Wt and I85RLDH mutant. The Wt S. rum enzyme structure binds NADH and malonate, whilst also resembling the typical compact R-active state of canonical LDHs. The structure of the mutant with I85R was solved in the Apo State (without ligand), and shows no large conformational reorganization such as that observed with canonical allosteric LDHs in Apo state. This is due to a local structural feature typical of S. rum LDH that prevents large-scale conformational reorganization. The S. rum LDH was also studied using Molecular Dynamics simulations, probing specific local deformations of the active site that allow the S. rum LDH to sample the T-inactive state. We propose that, with respect to the LDH/MalDH superfamily, the S. rum enzyme possesses a specificstructural and dynamical way to ensure homotropic activation.


Asunto(s)
L-Lactato Deshidrogenasa , Ácido Láctico , Regulación Alostérica , L-Lactato Deshidrogenasa/metabolismo , Selenomonas/genética , Selenomonas/metabolismo , Malato Deshidrogenasa/química
2.
J Appl Microbiol ; 132(4): 2661-2672, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35104035

RESUMEN

AIMS: To explore the impact of ambient pH on lactate catabolism by Megasphaera elsdenii BE2-2083 and Selenomonas ruminantium HD4 in both pure culture and in binary mixed culture. METHODS AND RESULTS: The growth rate, substrate consumption, product formation, enzymatic activity and gene expression of M. elsdenii and S. ruminantium at various pHs were examined. Furthermore, the metabolism of lactate catabolism pathways for M. elsdenii and S. ruminantium in the co-culture system was investigated by chasing the conversion of sodium L-[3-13 C]-lactate in nuclear magnetic resonance. In the pure culture systems, ambient pH had significant effects on the growth of M. elsdenii, whereas S. ruminantium was less sensitive to pH changes. In addition, lactate metabolic genes and activities of key enzymes were affected by ambient pH in M. elsdenii and S. ruminantium. In the co-culture system, low ambient pH reduced the contribution lactate catabolism by M. elsdenii. CONCLUSION: M. elsdenii BE2-2083 and S. ruminantium HD4 lactate degradation affected by ambient pH. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the regulatory mechanisms of lactate decomposing bacteria in lactate catabolism under the condition of subacute ruminal acidosis.


Asunto(s)
Acidosis , Selenomonas , Acidosis/veterinaria , Animales , Ácido Láctico/metabolismo , Megasphaera elsdenii/metabolismo , Rumen/microbiología , Selenomonas/genética , Selenomonas/metabolismo
3.
PLoS One ; 15(11): e0242158, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33170886

RESUMEN

Calcium salts of long-chain fatty acids (CSFA) from linseed oil have the potential to reduce methane (CH4) production from ruminants; however, there is little information on the effect of supplementary CSFA on rumen microbiome as well as CH4 production. The aim of the present study was to evaluate the effects of supplementary CSFA on ruminal fermentation, digestibility, CH4 production, and rumen microbiome in vitro. We compared five treatments: three CSFA concentrations-0% (CON), 2.25% (FAL) and 4.50% (FAH) on a dry matter (DM) basis-15 mM of fumarate (FUM), and 20 mg/kg DM of monensin (MON). The results showed that the proportions of propionate in FAL, FAH, FUM, and MON were increased, compared with CON (P < 0.05). Although DM and neutral detergent fiber expressed exclusive of residual ash (NDFom) digestibility decreased in FAL and FAH compared to those in CON (P < 0.05), DM digestibility-adjusted CH4 production in FAL and FAH was reduced by 38.2% and 63.0%, respectively, compared with that in CON (P < 0.05). The genera Ruminobacter, Succinivibrio, Succiniclasticum, Streptococcus, Selenomonas.1, and Megasphaera, which are related to propionate production, were increased (P < 0.05), while Methanobrevibacter and protozoa counts, which are associated with CH4 production, were decreased in FAH, compared with CON (P < 0.05). The results suggested that the inclusion of CSFA significantly changed the rumen microbiome, leading to the acceleration of propionate production and the reduction of CH4 production. In conclusion, although further in vivo study is needed to evaluate the reduction effect on rumen CH4 production, CSFA may be a promising candidate for reduction of CH4 emission from ruminants.


Asunto(s)
Calcio/química , Ácidos Grasos/química , Aceite de Linaza/química , Metano/química , Microbiota , Rumen/microbiología , Sales (Química)/química , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Peso Corporal , Análisis por Conglomerados , ADN Bacteriano/metabolismo , Detergentes , Digestión , Fermentación , Fumaratos/química , Gases , Técnicas In Vitro , Megasphaera/metabolismo , Monensina/química , ARN Ribosómico 16S/metabolismo , Selenomonas/metabolismo , Ovinos , Ensilaje/análisis , Streptococcus/metabolismo
4.
Arch Anim Nutr ; 74(4): 296-308, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32308036

RESUMEN

Grape pomace (GP) is an abundant by-product from wine production and is rich in phenolic compounds, unsaturated fatty acids, dietary fibre and beneficial bacteria. In this study, weaned piglets were fed a basic diet supplemented with 5% GP for 4 weeks. Compared with those in the control (CON) group, it was found that the proportion of Lactobacillus delbrueckii, Olsenella umbonata and Selenomonas bovis in the caecum and the villus height and villus height/crypt depth ratio (VCR) of the jejunum were both significantly increased in the GP group (p < 0.05). Meanwhile, at the mRNA expression level, several proinflammatory cytokines (IL-1ß, IL-8, IL-6 and TNF-α) were significantly downregulated (p < 0.05) in piglet caecal tissue, and the short-chain fatty acid receptors (GPR41 and GPR43) were not significantly upregulated. In contrast, the levels of IgG was significantly increased (p < 0.05) in the sera of weaned piglets in the GP group. However, no difference in growth performance between the two groups of piglets was detected. These results show that GP had no adverse effects on the growth performance of piglets, but GP can promote the content of some beneficial bacteria in the caecum; this effect is conducive to improving the disease resistance potential of piglets.


Asunto(s)
Bacterias/metabolismo , Microbioma Gastrointestinal/efectos de los fármacos , Sus scrofa/crecimiento & desarrollo , Sus scrofa/microbiología , Vitis/química , Actinobacteria/metabolismo , Alimentación Animal/análisis , Animales , Ciego/efectos de los fármacos , Ciego/microbiología , ADN Bacteriano/análisis , ADN Ribosómico/análisis , Dieta/veterinaria , Suplementos Dietéticos/análisis , Femenino , Frutas/química , Yeyuno/efectos de los fármacos , Yeyuno/fisiología , Lactobacillus delbrueckii/metabolismo , Masculino , Probióticos , Distribución Aleatoria , Selenomonas/metabolismo
5.
Mol Cell Proteomics ; 17(4): 721-736, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29339411

RESUMEN

Flagellated, Gram-negative, anaerobic, crescent-shaped Selenomonas species are colonizers of the digestive system, where they act at the interface between health and disease. Selenomonas sputigena is also considered a potential human periodontal pathogen, but information on its virulence factors and underlying pathogenicity mechanisms is scarce. Here we provide the first report of a Selenomonas glycoprotein, showing that S. sputigena produces a diversely and heavily O-glycosylated flagellin C9LY14 as a major cellular protein, which carries various hitherto undescribed rhamnose- and N-acetylglucosamine linked O-glycans in the range from mono- to hexasaccharides. A comprehensive glycomic and glycoproteomic assessment revealed extensive glycan macro- and microheterogeneity identified from 22 unique glycopeptide species. From the multiple sites of glycosylation, five were unambiguously identified on the 437-amino acid C9LY14 protein (Thr149, Ser182, Thr199, Thr259, and Ser334), the only flagellin protein identified. The O-glycans additionally showed modifications by methylation and putative acetylation. Some O-glycans carried hitherto undescribed residues/modifications as determined by their respective m/z values, reflecting the high diversity of native S. sputigena flagellin. We also found that monosaccharide rearrangement occurred during collision-induced dissociation (CID) of protonated glycopeptide ions. This effect resulted in pseudo Y1-glycopeptide fragment ions that indicated the presence of additional glycosylation sites on a single glycopeptide. CID oxonium ions and electron transfer dissociation, however, confirmed that just a single site was glycosylated, showing that glycan-to-peptide rearrangement can occur on glycopeptides and that this effect is influenced by the molecular nature of the glycan moiety. This effect was most pronounced with disaccharides. This study is the first report on O-linked flagellin glycosylation in a Selenomonas species, revealing that C9LY14 is one of the most heavily glycosylated flagellins described to date. This study contributes to our understanding of the largely under-investigated surface properties of oral bacteria. The data have been deposited to the ProteomeXchange with identifier PXD005859.


Asunto(s)
Flagelina/metabolismo , Selenomonas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Flagelina/genética , Glicopéptidos/metabolismo , Glicosilación , Periodontitis , Polisacáridos/metabolismo , Proteómica , Proteínas Recombinantes/metabolismo , Ramnosa/metabolismo , Selenomonas/genética
6.
Anim Sci J ; 89(2): 377-385, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29044947

RESUMEN

The fibrolytic rumen bacterium Ruminococcus flavefaciensOS14 was isolated from swamp buffalo and its phylogenetic, ecological and digestive properties were partially characterized. Isolates from rumen contents of four swamp buffalo were screened for fibrolytic bacteria; one of the 40 isolates showed a distinctive feature of solubilizing cellulose powder in liquid culture and was identified as R. flavefaciens based on its 16S ribosomal DNA sequence. This isolate, OS14, was employed for detection and digestion studies, for which a quantitative PCR assay was developed and defined cultures were tested with representative forages in Thailand. OS14 was phylogenetically distant from other isolated and uncultured R. flavefaciens and showed limited distribution among Thai ruminants but was absent in Japanese cattle. OS14 digested rice straw and other tropical forage to a greater extent than the type strain C94 of R. flavefaciens. OS14 produced more lactate than C94, and digested para grass to produce propionate more extensively in co-culture with lactate-utilizing Selenomonas ruminantium S137 than a co-culture of C94 with S137. These results indicate that phylogenetically distinct OS14 could digest Thai local forage more efficiently than the type strain, possibly forming a symbiotic cross-feeding relationship with lactate-utilizing bacteria. This strain might be useful for future animal and other industrial applications.


Asunto(s)
Búfalos/microbiología , Fibras de la Dieta/metabolismo , Filogenia , Rumen/microbiología , Ruminococcus/genética , Ruminococcus/fisiología , Animales , Celulosa/metabolismo , Técnicas de Cocultivo , ADN Bacteriano/genética , Lactatos/metabolismo , Oryza/metabolismo , Propionatos/metabolismo , ARN Ribosómico 16S/genética , Ruminococcus/aislamiento & purificación , Ruminococcus/metabolismo , Selenomonas/metabolismo , Selenomonas/fisiología
7.
Anaerobe ; 42: 6-16, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27451293

RESUMEN

Here, we examined diurnal changes in the ruminal microbial community and fermentation characteristics of dairy cows fed total mixed rations containing either corn silage (CS) or grass silage (GS) as forage. The rations, which consisted of 52% concentrate and 48% GS or CS, were offered for ad libitum intake over 20 days to three ruminal-fistulated lactating Jersey cows during three consecutive feeding periods. Feed intake, ruminal pH, concentrations of short chain fatty acids and ammonia in rumen liquid, as well as abundance change in the microbial populations in liquid and solid fractions, were monitored in 4-h intervals on days 18 and 20. The abundance of total bacteria and Fibrobacter succinogenes increased in solids in cows fed CS instead of GS, and that of protozoa increased in both solid and liquid fractions. Feeding GS favored numbers of F. succinogenes and Selenomonas ruminantium in the liquid fraction as well as the numbers of Ruminobacter amylophilus, Prevotella bryantii and ruminococci in both fractions. Minor effects of silage were detected on populations of methanogens. Despite quantitative changes in the composition of the microbial community, fermentation characteristics were less affected by forage source. These results suggest a functional adaptability of the ruminal microbiota to total mixed rations containing either GS or CS as the source of forage. Diurnal changes in microbial populations were primarily affected by feed intake and differed between species and fractions, with fewer temporal fluctuations evident in the solid than in the liquid fraction. Interactions between forage source and sampling time were of minor importance to most of the microbial species examined. Thus, diurnal changes of microbial populations and fermentative activity were less affected by the two silages.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Ritmo Circadiano/fisiología , Microbioma Gastrointestinal/fisiología , Rumen/microbiología , Ensilaje , Amoníaco/metabolismo , Alimentación Animal/análisis , Animales , Bovinos , Ácidos Grasos/metabolismo , Femenino , Fermentación , Fibrobacter/metabolismo , Fístula Gástrica , Concentración de Iones de Hidrógeno , Lactancia/fisiología , Poaceae/química , Poaceae/metabolismo , Prevotella/metabolismo , Ruminococcus/metabolismo , Selenomonas/metabolismo , Ensilaje/análisis , Zea mays/química , Zea mays/metabolismo
8.
J Nutr ; 146(9): 1714-21, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27511925

RESUMEN

BACKGROUND: Different carbohydrates ingested greatly influence rumen fermentation and microbiota and gaseous methane emissions. Dissolved hydrogen concentration is related to rumen fermentation and methane production. OBJECTIVES: We tested the hypothesis that carbohydrates ingested greatly alter the rumen environment in dairy cows, and that dissolved hydrogen concentration is associated with these changes in rumen fermentation and microbiota. METHODS: Twenty-eight lactating Chinese Holstein dairy cows [aged 4-5 y, body weight 480 ± 37 kg (mean ± SD)] were used in a randomized complete block design to investigate effects of 4 diets differing in forage content (45% compared with 35%) and source (rice straw compared with a mixture of rice straw and corn silage) on feed intake, rumen fermentation, and microbial populations. RESULTS: Feed intake (10.7-12.6 kg/d) and fiber degradation (0.584-0.692) greatly differed (P ≤ 0.05) between cows fed the 4 diets, leading to large differences (P ≤ 0.05) in gaseous methane yield (27.2-37.3 g/kg organic matter digested), dissolved hydrogen (0.258-1.64 µmol/L), rumen fermentation products, and microbiota. Ruminal dissolved hydrogen was negatively correlated (r < -0.40; P < 0.05) with molar proportion of acetate, numbers of fungi, abundance of Fibrobacter succinogenes, and methane yield, but positively correlated (r > 0.40; P < 0.05) with molar proportions of propionate and n-butyrate, numbers of methanogens, and abundance of Selenomonas ruminantium and Prevotella spp. Ruminal dissolved hydrogen was positively correlated (r = 0.93; P < 0.001) with Gibbs free energy changes of reactions producing greater acetate and hydrogen, but not correlated with those reactions producing more propionate without hydrogen. CONCLUSIONS: Changes in fermentation pathways from acetate toward propionate production and in microbiota from fibrolytic toward amylolytic species were closely associated with ruminal dissolved hydrogen in lactating dairy cows. An unresolved paradox was that greater dissolved hydrogen was associated with greater numbers of methanogens but with lower gaseous methane emissions.


Asunto(s)
Alimentación Animal/análisis , Dieta/veterinaria , Carbohidratos de la Dieta/administración & dosificación , Microbioma Gastrointestinal , Hidrógeno/metabolismo , Rumen/microbiología , Animales , Bovinos , Femenino , Fermentación , Fibrobacter/aislamiento & purificación , Fibrobacter/metabolismo , Lactancia , Metano/metabolismo , Modelos Teóricos , Prevotella/aislamiento & purificación , Prevotella/metabolismo , Selenomonas/aislamiento & purificación , Selenomonas/metabolismo
9.
Biosci Biotechnol Biochem ; 80(10): 1954-9, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27310312

RESUMEN

The major outer membrane protein Mep45 of Selenomonas ruminantium, an anaerobic Gram-negative bacterium, comprises two distinct domains: the N-terminal S-layer homologous (SLH) domain that protrudes into the periplasm and binds to peptidoglycan, and the remaining C-terminal transmembrane domain, whose function has been unknown. Here, we solubilized and purified Mep45 and characterized its function using proteoliposomes reconstituted with Mep45. We found that Mep45 forms a nonspecific diffusion channel via its C-terminal region. The channel was permeable to solutes smaller than a molecular weight of roughly 600, and the estimated pore radius was 0.58 nm. Truncation of the SLH domain did not affect the channel property. On the basis of the fact that Mep45 is the most abundant outer membrane protein in S. ruminantium, we conclude that Mep45 serves as a main pathway through which small solutes diffuse across the outer membrane of this bacterium.


Asunto(s)
Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Membrana Celular/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/metabolismo , Rumen/microbiología , Selenomonas/metabolismo , Anaerobiosis , Animales , Proteínas Bacterianas/aislamiento & purificación , Difusión , Proteínas de la Membrana/aislamiento & purificación , Dominios Proteicos , Estabilidad Proteica , Solubilidad
10.
J Dairy Sci ; 99(1): 245-57, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26601577

RESUMEN

Fructans are an important nonfiber carbohydrate in cool season grasses. Their fermentation by ruminal microbes is not well described, though such information is needed to understand their nutritional value to ruminants. Our objective was to compare kinetics and product formation of orchardgrass fructan (phlein; PHL) to other nonfiber carbohydrates when fermented in vitro with mixed or pure culture ruminal microbes. Studies were carried out as randomized complete block designs. All rates given are first-order rate constants. With mixed ruminal microbes, rate of substrate disappearance tended to be greater for glucose (GLC) than for PHL and chicory fructan (inulin; INU), which tended to differ from each other (0.74, 0.62, and 0.33 h(-1), respectively). Disappearance of GLC had almost no lag time (0.04 h), whereas the fructans had lags of 1.4h. The maximum microbial N accumulation, a proxy for cell growth, tended to be 20% greater for PHL and INU than for GLC. The N accumulation rate for GLC (1.31h(-1)) was greater than for PHL (0.75 h(-1)) and INU (0.26 h(-1)), which also differed. More microbial glycogen (+57%) was accumulated from GLC than from PHL, though accumulation rates did not differ (1.95 and 1.44 h(-1), respectively); little glycogen accumulated from INU. Rates of organic acid formation were 0.80, 0.28, and 0.80 h(-1) for GLC, INU, and PHL, respectively, with PHL tending to be greater than INU. Lactic acid production was more than 7-fold greater for GLC than for the fructans. The ratio of microbial cell carbon to organic acid carbon tended to be greater for PHL (0.90) and INU (0.86) than for GLC (0.69), indicating a greater yield of cell mass per amount of substrate fermented with fructans. Reduced microbial yield for GLC may relate to the greater glycogen production that requires ATP, and lactate production that yields less ATP; together, these processes could have reduced ATP available for cell growth. Acetate molar proportion was less for GLC than for fructans, and less for PHL than for INU. In studies with pure cultures, all microbes evaluated showed differences in specific growth rate constants (µ) for GLC, fructose, sucrose, maltose, and PHL. Selenomonas ruminantium and Streptococcus bovis showed the highest µ for PHL (0.55 and 0.67 h(-1), respectively), which were 50 to 60% of the µ achieved for GLC. The 10 other species tested had µ between 0.01 and 0.11h(-1) with PHL. Ruminal microbes use PHL differently than they do GLC or INU.


Asunto(s)
Dactylis/metabolismo , Fructanos/metabolismo , Inulina/metabolismo , Selenomonas/metabolismo , Streptococcus bovis/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Metabolismo de los Hidratos de Carbono , Carbono/metabolismo , Cichorium intybus/metabolismo , Dactylis/química , Fermentación , Fructosa/metabolismo , Glucosa/metabolismo , Glucógeno/metabolismo , Cinética , Ácido Láctico/metabolismo , Maltosa/metabolismo , Rumen/microbiología , Especificidad de la Especie , Sacarosa/metabolismo
11.
Br J Nutr ; 114(3): 358-67, 2015 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-26123320

RESUMEN

The ruminant provides a powerful model for understanding the temporal dynamics of gastrointestinal microbial communities. Diet-induced milk fat depression (MFD) in the dairy cow is caused by rumen-derived bioactive fatty acids, and is commonly attributed to the changes in the microbial population. The aim of the present study was to determine the changes occurring in nine ruminal bacterial taxa with well-characterised functions, and abundance of total fungi, ciliate protozoa and bacteria during the induction of and recovery from MFD. Interactions between treatment and time were observed for ten of the twelve populations. The total number of both fungi and ciliate protozoa decreased rapidly (days 4 and 8, respectively) by more than 90% during the induction period and increased during the recovery period. The abundance of Streptococcus bovis (amylolytic) peaked at 350% of control levels on day 4 of induction and rapidly decreased during the recovery period. The abundance of Prevotella bryantii (amylolytic) decreased by 66% from day 8 to 20 of the induction period and increased to the control levels on day 12 of the recovery period. The abundance of Megasphaera elsdenii and Selenomonas ruminantium (lactate-utilising bacteria) increased progressively until day 12 of induction (>170%) and decreased during the recovery period. The abundance of Fibrobacter succinogenes (fibrolytic) decreased by 97% on day 4 of induction and increased progressively to an equal extent during the recovery period, although smaller changes were observed for other fibrolytic bacteria. The abundance of the Butyrivibrio fibrisolvens/Pseudobutyrivibrio group decreased progressively during the induction period and increased during the recovery period, whereas the abundance of Butyrivibrio hungatei was not affected by treatment. Responsive taxa were modified rapidly, with the majority of changes occurring within 8 d and their time course was similar to the time course of the induction of MFD, demonstrating a strong correlation between changes in ruminal microbial populations and MFD.


Asunto(s)
Dieta/veterinaria , Grasas/análisis , Leche/química , Rumen/microbiología , Animales , Bacterias/clasificación , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Carga Bacteriana , Butyrivibrio/aislamiento & purificación , Butyrivibrio/metabolismo , Bovinos , Dieta/efectos adversos , Ácidos Grasos/biosíntesis , Ácidos Grasos/farmacología , Femenino , Fibrobacter/aislamiento & purificación , Fibrobacter/metabolismo , Lactancia , Lípidos , Megasphaera/aislamiento & purificación , Megasphaera/metabolismo , Microbiota/fisiología , Prevotella/aislamiento & purificación , Prevotella/metabolismo , Selenomonas/aislamiento & purificación , Selenomonas/metabolismo , Streptococcus bovis/aislamiento & purificación , Streptococcus bovis/metabolismo
12.
World J Microbiol Biotechnol ; 29(1): 87-102, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22932808

RESUMEN

Biosurfactant-producing bacteria, isolate CT2, was isolated from mangrove sediment in the south of Thailand. The sequence of the 16S rRNA gene from isolate CT2 showed 100 % similarity with Selenomonas ruminantium. The highest biosurfactant production (5.02 g/l) was obtained when the cells were grown on minimal salt medium containing 15 g/l molasses and 1 g/l commercial monosodium glutamate supplemented with 1 g/l NaCl, 0.1 g/l leucine, 5 % (v/v) inoculum size at 30 °C and 150 rpm after 54 h of cultivation. The biosurfactant obtained by extraction with ethyl acetate showed high surface tension reduction (25.5 mN/m), a small CMC value (8 mg/l), thermal and pH stability with respect to surface tension reduction and emulsification activity and a high level of salt tolerance. The biosurfactant obtained was confirmed as a lipopeptide by using a biochemical test, FT-IR, MNR and mass spectrometry. The crude biosurfactant showed a broad spectrum of antimicrobial activity and also had the ability to emulsify oil and enhance PAHs solubility.


Asunto(s)
Sedimentos Geológicos/microbiología , Selenomonas/aislamiento & purificación , Selenomonas/metabolismo , Tensoactivos/química , Aminoácidos/metabolismo , Medios de Cultivo/metabolismo , Emulsiones/química , Concentración de Iones de Hidrógeno , Micelas , Aceites , ARN Ribosómico 16S/genética , Selenomonas/genética , Cloruro de Sodio/metabolismo , Tensión Superficial , Temperatura , Tailandia
13.
J Nutr Sci Vitaminol (Tokyo) ; 58(3): 153-60, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22878384

RESUMEN

Polyamine is a small organic polycation composed of a hydrocarbon backbone with multiple amino groups which ubiquitously exists in all living organisms from bacteria to higher animals. The critical step of polyamine biosynthesis generally includes the amino acid-decarboxylating reaction to produce the primary diamines, such as a synthesis of putrescine (NH(3)(+)·(CH(2))(4)·NH(3)(+)) from ornithine, and cadaverine (NH(3)(+)·(CH(2))(5)·NH(3)(+)) from lysine, which are catalyzed by pyridoxal-5'-phosphate (PLP; vitamin B(6))-dependent decarboxylases. Synthesized polyamines are implicated in a wide variety of cytoplasmic reactions such as DNA replication and protein synthesis, and are essential for proper growth of the organisms. However, in Selenomonas ruminantium, a strictly anaerobic Gram-negative bacterium dominant in sheep rumen, cadaverine displays its function in a quite distinctive scheme compared to the general bacteria reported. It serves as an essential constituent of the peptidoglycan for the maintenance of envelope integrity through an interaction with the periplasm-exposed SLH domain of Mep45, the outer membrane protein of this bacterium. Furthermore, cytoplasmic biosynthesis of cadaverine occurs totally in a eukaryotic-like manner rather than in a conventional way of bacteria. Lysine/ornithine decarboxylase (LDC/ODC), a PLP-dependent enzyme responsible for cadaverine synthesis in this bacterium, displays significant homology to the eukaryotic ODC but not to the general bacterial LDC nor ODC, and its activity is tightly regulated by antizyme-mediated proteolysis, a regulatory process generally found in eukaryotes. These findings represent the biological diversity of this bacterium beyond the preexisting knowledge related to the polyamine-physiology, cell envelope-architecture, and the regulatory system for the enzyme. In this review we will describe (i) the cadaverine-containing peptidoglycan of S. ruminantium: its chemical structure, biosynthesis, and biological function, and (ii) cellular biosynthesis of cadaverine by LDC/ODC and its antizyme-mediated regulation. In addition, we will briefly refer to (iii) the phylogenetic position and characteristics of S. ruminantium and its unique cadaverine-physiology.


Asunto(s)
Cadaverina/metabolismo , Peptidoglicano/metabolismo , Selenomonas/metabolismo , Selenomonas/ultraestructura , Animales , Proteínas de la Membrana Bacteriana Externa/metabolismo , Cadaverina/biosíntesis , Carboxiliasas/metabolismo , Ornitina Descarboxilasa/metabolismo , Peptidoglicano/química , Filogenia , Rumen/microbiología , Selenomonas/clasificación , Ovinos/microbiología
14.
Animal ; 6(11): 1788-94, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22717128

RESUMEN

This study investigated the effects of disodium fumarate (DF) on methane emission, ruminal fermentation and microbial abundance in goats under different forage (F) : concentrate (C) ratios and fed according to maintenance requirements. Four ruminally fistulated, castrated male goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments and the main factors being the F : C ratios (41 : 59 or 58 : 42) and DF supplementation (0 or 10 g/day). DF reduced methane production (P < 0.05) on average by 11.9%, irrespective of the F : C ratio. The concentrations of total volatile fatty acids, acetate and propionate were greater in the rumen of goats supplemented with DF (P < 0.05), whereas the abundance of methanogens was lower (P < 0.05). In high-forage diets, the abundance of Selenomonas ruminantium, a fumarate-reducing bacterium, was greater in the rumen of goats supplemented with DF. The abundance of fungi, protozoa, Ruminococus flavefaciens and Fibrobacter succinogenes were not affected by the addition of DF. Variable F : C ratios affected the abundance of methanogens, fungi and R. flavefaciens (P < 0.05), but did not affect methane emission. The result implied that DF had a beneficial effect on the in vivo rumen fermentation of the goats fed diets with different F : C ratios and that this effect were not a direct action on anaerobic fungi, protozoa and fibrolytic bacteria, the generally recognized fiber-degrading and hydrogen-producing microorganisms, but due to the stimulation of fumarate-reducing bacteria and the depression of methanogens.


Asunto(s)
Fermentación/efectos de los fármacos , Fumaratos/farmacología , Cabras/metabolismo , Rumen/efectos de los fármacos , Acetatos/análisis , Animales , Dieta/veterinaria , Ácidos Grasos Volátiles/análisis , Fermentación/fisiología , Fibrobacter/efectos de los fármacos , Fibrobacter/metabolismo , Fumaratos/administración & dosificación , Contenido Digestivo/química , Contenido Digestivo/microbiología , Cabras/microbiología , Cabras/fisiología , Masculino , Propionatos/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Rumen/metabolismo , Rumen/microbiología , Rumen/fisiología , Ruminococcus/efectos de los fármacos , Ruminococcus/metabolismo , Selenomonas/efectos de los fármacos , Selenomonas/metabolismo
15.
Appl Environ Microbiol ; 78(7): 2386-92, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22267666

RESUMEN

The transition period is a severe challenge to dairy cows. Glucose supply cannot meet demand and body fat is mobilized, potentially leading to negative energy balance (NEB), ketosis, or fatty liver. Propionate produces glucose by gluconeogenesis, which depends heavily on the number and species of microbes. In the present study, we analyzed the rumen microbiome composition of cows in the transition period, cows with ketosis, and nonperinatal cows by terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes and quantitative PCR. TRFLP analysis indicated that the quantity of Veillonellaceae organisms was reduced and that of Streptococcaceae organisms was increased in rumen samples from the transition period and ketosis groups, with the number of Lactobacillaceae organisms increased after calving. Quantitative PCR data suggested that the numbers of the main propionate-producing microbes, Megasphaera elsdenii and Selenomonas ruminantium, were decreased, while numbers of the main lactate-producing bacterium, Streptococcus bovis, were increased in the rumen of cows from the transition period and ketosis groups, with the number of Lactobacillus sp. organisms increased after calving. Volatile fatty acid (VFA) and glucose concentrations were decreased, but the lactic acid concentration was increased, in rumen samples from the transition period and ketosis groups. Our results indicate that the VFA concentration is significantly related to the numbers of Selenomonas ruminantium and Megasphaera elsdenii organisms in the rumen.


Asunto(s)
Ácidos Grasos Volátiles/análisis , Cetosis , Lactancia/fisiología , Preñez/fisiología , Rumen/química , Rumen/microbiología , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Bacterias/clasificación , Bacterias/genética , Bacterias/crecimiento & desarrollo , Bovinos , Industria Lechera , Ecosistema , Ácidos Grasos Volátiles/metabolismo , Femenino , Genes de ARNr , Megasphaera/genética , Megasphaera/aislamiento & purificación , Megasphaera/metabolismo , Metagenoma , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Embarazo , ARN Ribosómico 16S/genética , Rumen/metabolismo , Selenomonas/genética , Selenomonas/aislamiento & purificación , Selenomonas/metabolismo
16.
FEMS Microbiol Lett ; 325(2): 170-9, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22092507

RESUMEN

Selenomonas ruminantium strains were isolated from sheep rumen, and their significance for fiber digestion was evaluated. Based on the phylogenetic classification, two clades of S. ruminantium (clades I and II) were proposed. Clade II is newly found, as it comprised only new isolates that were phylogenetically distant from the type strain, while all of the known isolates were grouped in the major clade I. More than half of clade I isolates displayed CMCase activity with no relation to the degree of bacterial adherence to fibers. Although none of the isolates digested fiber in monoculture, they stimulated fiber digestion when co-cultured with Fibrobacter succinogenes, and there was an enhancement of propionate production. The extent of such synergy depended on the clade, with higher digestion observed by co-culture of clade I isolates with F. succinogenes than by co-culture with clade II isolates. Quantitative PCR analysis showed that bacterial abundance in the rumen was higher for clade I than for clade II. These results suggest that S. ruminantium, in particular the major clade I, is involved in rumen fiber digestion by cooperating with F. succinogenes.


Asunto(s)
Fibras de la Dieta/metabolismo , Digestión/fisiología , Rumen/microbiología , Selenomonas/metabolismo , Análisis de Varianza , Animales , Adhesión Bacteriana , Celulosa/metabolismo , Técnicas de Cocultivo , ADN Bacteriano/genética , Fibrobacter/metabolismo , Filogenia , Propionatos/metabolismo , ARN Ribosómico 16S/genética , Rumen/metabolismo , Selenomonas/genética , Selenomonas/aislamiento & purificación , Ovinos/microbiología
17.
J Bacteriol ; 193(9): 2347-50, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21398553

RESUMEN

In Selenomonas ruminantium, a strictly anaerobic and gram-negative bacterium, cadaverine covalently linked to the peptidoglycan is required for the interaction between the peptidoglycan and the S-layer homologous (SLH) domain of the major outer membrane protein Mep45. Here, using a series of diamines with a general structure of NH(3)(+)(CH(2))(n)NH(3)(+) (n = 3 to 6), we found that cadaverine (n = 5) specifically serves as the most efficient constituent of the peptidoglycan in acquiring the high resistance of the cell to external damage agents and is required for effective interaction between the SLH domain of Mep45 and the peptidoglycan, facilitating the correct anchoring of the outer membrane to the peptidoglycan.


Asunto(s)
Cadaverina/química , Cadaverina/metabolismo , Peptidoglicano/química , Peptidoglicano/metabolismo , Selenomonas/citología , Selenomonas/metabolismo , Proteínas de la Membrana Bacteriana Externa , Membrana Celular/fisiología , Pared Celular , Regulación Bacteriana de la Expresión Génica , Unión Proteica , Selenomonas/genética
18.
Folia Microbiol (Praha) ; 55(4): 315-8, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20680561

RESUMEN

The inter- and intraspecies variability of lactate dehydrogenase (ldh) gene was determined among the predominant ruminal lactate utilizing bacteria. Nearly complete nucleotide sequences of ldh gene, encoding NAD-dependent lactate dehydrogenase of three Megasphaera elsdenii and six Selenomonas ruminantium strains, were obtained and compared. Phylogenetic analyses revealed a limited variability between the ldh sequences studied. The majority of differences observed were silent mutations at the 3rd position of codons. Surprisingly, the intraspecies diversity of the ldh gene among S. ruminantium isolates was higher than the interspecies level between S. ruminantium and M. elsdenii, which strongly suggests the possibility of acquisition of this gene by horizontal gene transfer.


Asunto(s)
Proteínas Bacterianas/genética , Variación Genética , L-Lactato Deshidrogenasa/genética , Ácido Láctico/metabolismo , Megasphaera/enzimología , Rumen/microbiología , Selenomonas/enzimología , Animales , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , Megasphaera/genética , Megasphaera/aislamiento & purificación , Megasphaera/metabolismo , Datos de Secuencia Molecular , Filogenia , Mutación Puntual , Selenomonas/genética , Selenomonas/aislamiento & purificación , Selenomonas/metabolismo , Análisis de Secuencia de ADN , Homología de Secuencia
19.
Waste Manag ; 30(12): 2622-30, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20727727

RESUMEN

Animal fleshing (ANFL) is the major proteinaceous solid waste generated during the manufacture of leather, which requires to be disposed of by environmentally sound manner. This study reports about the treatment of ANFL into an organic compost and its effects on physiological parameters of different crops in a laboratory study. The ANFL was hydrolysed using Selenomonas ruminantium HM000123 and then the hydrolysed ANFL was mixed with cow dung and leaf litter for producing composted organic fertilizer (COF). The COF was characterized for pH, electrical conductivity (EC), total Kjeldhal nitrogen (TKN), and total organic carbon (TOC). The composting resulted in a significant reduction in pH, TOC and C:N ratio and an increase in TKN after 49 days in a compost reactor. Scanning electron microscope and FT-IR were used to analyse the hydrolysis of intra structural ANFL matrix and changes in the functional groups, respectively, in initial and final day COF. Thermogravimetry (TG) analysis was carried out for the raw mixture and COF samples to identify the weight loss under the nitrogen environment. The relative seed germination was found to be 94% in tomato (Lycopersicon esculentum), 92% in green gram (Vigna radiata), 86% in bottle gourd (Lagenaria siceraria (Mol.) Standl.) and 84% in cucumber (Cucumis sativus L.) using the extracts of COF. The results indicate that the combination of both hydrolysis and bacterial composting reduced the overall time required for composting and producing a nutrient-enriched compost product.


Asunto(s)
Residuos Industriales , Selenomonas/metabolismo , Piel/metabolismo , Curtiembre , Administración de Residuos/métodos , Anaerobiosis , Biodegradación Ambiental , Metales Pesados/análisis , Selenomonas/clasificación , Suelo/química , Contaminantes del Suelo/análisis , Contaminantes del Suelo/química , Contaminantes del Suelo/toxicidad
20.
Biosci Biotechnol Biochem ; 72(2): 445-55, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18256468

RESUMEN

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, in S. ruminantium. We purified and characterized ADC and cloned its gene (adc) from S. ruminantium chromosomal DNA. ADC showed more than 60% identity with those of LDC/ODC/ADCs from Gram-positive bacteria, but no similarity to that from Gram-negative bacteria. In this study, we also cloned the aguA and aguB genes, encoding agmatine deiminase (AguA) and N-carbamoyl-putrescine amidohydrolase (AguB), both of which are involved in conversion from agmatine into putrescine. AguA and AguB were expressed in S. ruminantium. Hence, we concluded that S. ruminantium has both ornithine and agmatine pathways for the synthesis of putrescine.


Asunto(s)
Agmatina/metabolismo , Putrescina/biosíntesis , Selenomonas/metabolismo , Secuencia de Aminoácidos , Arginina/metabolismo , Secuencia de Bases , Carboxiliasas/metabolismo , Cartilla de ADN , Inhibidores Enzimáticos/farmacología , Estabilidad de Enzimas , Datos de Secuencia Molecular , Ornitina Descarboxilasa/metabolismo , Selenomonas/enzimología , Homología de Secuencia de Aminoácido , Especificidad por Sustrato
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