scholarly journals Effects of extracellular pH on the intracellular pH and membrane potential of cellulolytic ruminal bacteria, Ruminococcus albus, Ruminococcus flavefaciens, and Fibrobacter succinogenes.

1992 ◽  
Vol 38 (6) ◽  
pp. 567-573 ◽  
Author(s):  
KOHJI MIYAZAKI ◽  
TSUNEO HINO ◽  
AND HISAO ITABASHI
Keyword(s):  
Membrane Potential ◽  
Intracellular Ph ◽  
Extracellular Ph ◽  
Fibrobacter Succinogenes ◽  
Ruminococcus Albus ◽  
Ruminococcus Flavefaciens ◽  
Ruminal Bacteria

scholarly journals Incorporation of [15N]Ammonia by the Cellulolytic Ruminal Bacteria Fibrobacter succinogenesBL2, Ruminococcus albus SY3, and Ruminococcus flavefaciens 17

2001 ◽  
Vol 67 (6) ◽  
pp. 2819-2822 ◽  
Author(s):  
Cengiz Atasoglu ◽  
C. James Newbold ◽  
R. John Wallace
Keyword(s):  
Amino Acids ◽  
Growth Media ◽  
Fibrobacter Succinogenes ◽  
Cellulolytic Bacteria ◽  
Ruminococcus Albus ◽  
Ruminococcus Flavefaciens ◽  
Ruminal Bacteria ◽  
Amino Acid Nitrogen ◽  
N Enrichment ◽  
High Concentrations

ABSTRACT The origin of cell nitrogen and amino acid nitrogen during growth of ruminal cellulolytic bacteria in different growth media was investigated by using 15NH3. At high concentrations of peptides (Trypticase, 10 g/liter) and amino acids (15.5 g/liter), significant amounts of cell nitrogen ofFibrobacter succinogenes BL2 (51%), Ruminococcus flavefaciens 17 (43%), and Ruminococcus albusSY3 (46%) were derived from non-NH3-N. With peptides at 1 g/liter, a mean of 80% of cell nitrogen was from NH3. More cell nitrogen was formed from NH3 during growth on cellobiose compared with growth on cellulose in all media. Phenylalanine was essential for F. succinogenes, and its15N enrichment declined more than that of other amino acids in all species when amino acids were added to the medium.

Ammonia movement and distribution after exercise across white muscle cell membranes in rainbow trout

1996 ◽  
Vol 271 (3) ◽  
pp. R738-R750 ◽  
Author(s):  
Y. Wang ◽  
G. J. Heigenhauser ◽  
C. M. Wood
Keyword(s):  
Membrane Potential ◽  
Cell Membrane ◽  
Intracellular Ph ◽  
Muscle Cell ◽  
Cell Membranes ◽  
White Muscle ◽  
Extracellular Ph ◽  
Posterior Portion ◽  
Arterial Inflow ◽  
Muscle Cell Membrane

Manipulations of pH and electrical gradients in a perfused preparation were used to analyze the factors controlling ammonia distribution and flux in trout white muscle after exercise. Trout were exercised to exhaustion, and then an isolated-perfused white muscle preparation with discrete arterial inflow and venous outflow was made from the posterior portion of the tail. The tail-trunks were perfused with low (7.4)-, medium (7.9)-, and high (8.4)-pH saline, achieved by varying HCO3- concentration ([HCO3-]) at constant Pco2. Intracellular and extracellular pH, ammonia, CO2, K+, Na+, and Cl- were measured. Muscle intracellular pH was not affected by changes in extracellular pH. Increasing extracellular pH caused a decrease in the transmembrane NH3 partial pressure (PNH3) gradient and a decrease in ammonia efflux. When extracellular K+ concentration was increased from 3.5 to 15 mM in the medium-pH group, a depolarization of the muscle cell membrane potential from -92 to -60 mV and a 0.1-unit depression in intracellular pH occurred. Ammonia efflux increased despite a marked reduction in the PNH3 gradient. Amiloride (10(-4) M) had no effect, indicating that Na+/H(+)-NH4+ exchange does not participate in ammonia transport in this system. A comparison of observed intracellular-to-extracellular ammonia distribution ratios with those modeled according to either pH or Nernst potential distributions supports a model in which ammonia distribution across white muscle cell membranes is affected by both pH and electrical gradients, indicating that the membranes are permeable to both NH3 and NH4+. Membrane potential, acting to retain high levels of NH4+ in the intracellular compartment, appears to have the dominant influence during the postexercise period. However, at rest, the pH gradient may be more important, resulting in much lower intracellular ammonia levels and distribution ratios. We speculate that the muscle cell membrane NH3-to-NH4+ permeability ratio in trout may change between the rest and postexercise condition.

Extracellular acidification at the surface of depolarized voltage-clamped snail neurones detected with eccentric combination pH microelectrodes

1987 ◽  
Vol 65 (5) ◽  
pp. 1001-1005 ◽  
Author(s):  
R. C. Thomas
Keyword(s):  
Membrane Potential ◽  
Intracellular Ph ◽  
Extracellular Ph ◽  
Electrochemical Gradient ◽  
Extracellular Acidification ◽  
Surface Ph ◽  
Buffering Power ◽  
Snail Neurones ◽  
Series Of Experiments ◽  
Ph Microelectrodes

A new design of double micropipette was used to measure intracellular pH, membrane potential, and surface pH of superfused snail neurones. A third double micropipette was used to control the membrane potential via a CsCl-filled barrel and inject HCl iontophoretically. In one series of experiments the surface pH fell by up to one-third of a pH unit when the membrane potential was clamped to 20 mV, pHi was initially 6.7, and extracellular pH was about 7.4 in a medium buffered either with 2 mM HEPES or 2.7% CO2 and 20 mM bicarbonate. In a second series in which surface pH was observed during brief depolarizations to different potentials with different pHi, the potential at which the surface began to acidify varied with pHi with a slope of 32 mV per pH unit. The results confirm that H+ ions leave depolarized snail neurones if the electrochemical gradient is favourable and show that CO2–bicarbonate buffered solutions have a low effective extracellular buffering power for rapid additions of acid.

scholarly journals In Vivo Competitions between Fibrobacter succinogenes, Ruminococcus flavefaciens, and Ruminoccus albus in a Gnotobiotic Sheep Model Revealed by Multi-Omic Analyses

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Carl J. Yeoman ◽  
Christopher J. Fields ◽  
Pascale Lepercq ◽  
Philippe Ruiz ◽  
Evelyne Forano ◽  
...  
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Fibrobacter Succinogenes ◽  
Plant Cell Walls ◽  
Cellulolytic Bacteria ◽  
Ruminococcus Albus ◽  
Ruminococcus Flavefaciens ◽  
Content Type

ABSTRACT Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens are the three predominant cellulolytic bacterial species found in the rumen. In vitro studies have shown that these species compete for adherence to, and growth upon, cellulosic biomass. Yet their molecular interactions in vivo have not heretofore been examined. Gnotobiotically raised lambs harboring a 17-h-old immature microbiota devoid of culturable cellulolytic bacteria and methanogens were inoculated first with F. succinogenes S85 and Methanobrevibacter sp. strain 87.7, and 5 months later, the lambs were inoculated with R. albus 8 and R. flavefaciens FD-1. Longitudinal samples were collected and profiled for population dynamics, gene expression, fibrolytic enzyme activity, in sacco fibrolysis, and metabolite profiling. Quantitative PCR, metagenome and metatranscriptome data show that F. succinogenes establishes at high levels initially but is gradually outcompeted following the introduction of the ruminococci. This shift resulted in an increase in carboxymethyl cellulase (CMCase) and xylanase activities but not in greater fibrolysis, suggesting that F. succinogenes and ruminococci deploy different but equally effective means to degrade plant cell walls. Expression profiles showed that F. succinogenes relied upon outer membrane vesicles and a diverse repertoire of CAZymes, while R. albus and R. flavefaciens preferred type IV pili and either CBM37-harboring or cellulosomal carbohydrate-active enzymes (CAZymes), respectively. The changes in cellulolytics also affected the rumen metabolome, including an increase in acetate and butyrate at the expense of propionate. In conclusion, this study provides the first demonstration of in vivo competition between the three predominant cellulolytic bacteria and provides insight on the influence of these ecological interactions on rumen fibrolytic function and metabolomic response. IMPORTANCE Ruminant animals, including cattle and sheep, depend on their rumen microbiota to digest plant biomass and convert it into absorbable energy. Considering that the extent of meat and milk production depends on the efficiency of the microbiota to deconstruct plant cell walls, the functionality of predominant rumen cellulolytic bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens, has been extensively studied in vitro to obtain a better knowledge of how they operate to hydrolyze polysaccharides and ultimately find ways to enhance animal production. This study provides the first evidence of in vivo competitions between F. succinogenes and the two Ruminococcus species. It shows that a simple disequilibrium within the cellulolytic community has repercussions on the rumen metabolome and fermentation end products. This finding will have to be considered in the future when determining strategies aiming at directing rumen fermentations for animal production.

scholarly journals Aislamiento, Patrón de Fermentación de Carbohidratos y Caracterización Morfológica de Bacterias Celulolíticas del Rumen de Bovinos Alimentados con Heno de Raigrás en Colombia

1996 ◽  
Vol 1 (1) ◽  
pp. 23 ◽  
Author(s):  
Fernando Rodriguez V. ◽  
Tito Efraín Diaz M. ◽  
Giselle A. Mackenzie ◽  
Luz Estella Guativa ◽  
Germán Afanador
Keyword(s):  
Cell Structure ◽  
Morphological Characterization ◽  
Fibrobacter Succinogenes ◽  
Cellulolytic Activity ◽  
Cellulolytic Bacteria ◽  
Biochemical Tests ◽  
Ruminococcus Albus ◽  
Ruminococcus Flavefaciens ◽  
Ultrastructural Studies ◽  
Carbohydrate Fermentation

<p>En el Centro Nacional de Investigaciones “Tibaitatá” de Corpoica, localizado en un ecosistema trópical a una altura de 2550 m.s.n.m, se adelantó un estudio para caracterizar la población de bacterias celulolíticas ruminales de bovinos. Cinco cepas de bacterias anaerobias celulolíticas fueron aisladas a partir del contenido ruminal de bovinos alimentados con heno de raigrás (Lolium multijlorum). Las pruebas bioquímicas, el patrón de fermentación de carbohidratos y la caracterización morfológica, incluyendo los estudios de microscopía electrónica de transmisión de la membrana celular y el glicocáliz, permitieron clasificar las cepas aisladas como: Fibrobacter succinogenes succinogenes (F31 y F32), Fibrobacter succinogenes elongata(F33), Ruminococcus albus (R38) y Ruminococcus flavefaciens (R39). La cepa de R. albus fermentó un mayor número de fuentes de carbono que la cepa de R. flavefaciens, pero ambas, fermentaron celobiosa, pectina y xilano. Ninguna de las dos subespecies de Fibrobacter aisladas fermentó pentosas. Las cepas de Fibrobacter presentaron morfologías de colonia en roll-tube de agar celobiosa, no repor­ tadas en la literatura. La apariencia, tamaño y distribución del glicocáliz en las células de las cepas del género Ruminococcus hicieron posible la diferenciación de sus dos espe­ cies R. albus y R. flavefaciens y la confirmación del status taxonómico de las otras cepas celulolíticas. Las cepas aisladas constituyen las primeras entradas al banco de germoplasma microbial de referencia para bovinos en Colombia. Actualmente se adelantan los estudios de actividad enzimática celulolítica de estas cepas.</p><p> </p><p> </p><p><strong>Isolation, Carbohydrate Fermentation Pattern and Morphological Characterization of Rumen Cellulolytic Bacteria of Cattle Fed Raygrass Hay in Colombia</strong></p><p>A Characterization study of rumen cellulolytic bacteria of cattle was conducted at the National Research Center "Tibaitatá" of Corpoica, located in a highland (2550 m.a.s.l) tropical ecosystem of Colombia. Five anaerobic strains of cellulolytic bacteria (F31, F32, F33, R38 and R39) were isolated from the rumen contents of cattle fed on raygrass (Lolium multiflorum) hay. Classification of the isolated rumen bacteria strains was accomplished by biochemical tests, carbohydrate fermentation patterns and morphological characterization, including transmission electron microscopy (TEM) of cell membrane and glycocalix. The isolated strains were: Fibrobacter succinogenes succinogenes (F31y F32), Fibrobacter succi nogenes elongata (F33), Ruminococcus albus (R38) and Ruminococcus flavefaciens (R39).</p><p>Ruminococcus albus fermented more carbohydrate sources than Ruminococcus flavefaciens, however, both species fermented cellobiose, pectin and xilan Fibrobacter isolates did not ferment pentose sugar s. Six different types of morphology of the colony, sorne of them not reported previously, were observed in Fibrobacter isolates growing on agar-containing roll­ tubes. Ruminococcus species were identified as R. albus and R. fla vefaciens by differences in cell structure, size and distribution of the glycocalix. Ultrastructural studies confirmed the taxonomic status of isolated bacteria species. Isolated bacteria are the first entries to the reference rumen germplasm bank of cattle in Colombia. Enzymatic assays are being conducted to measure cellulolytic activity of the isolated strains. </p>

scholarly journals Cell wall degradation of Bouteloua repens in vitro by pure cultures of R. flavefaciens and F. succinogenes isolate from cattle grazing tropical lowland pastures in Colombia

2003 ◽  
Vol 4 (1) ◽  
pp. 29 ◽  
Author(s):  
Faisury Ossa ◽  
Martha Arcos ◽  
Tito E. Díaz ◽  
Wolfgang Pittroff
Keyword(s):  
Cell Wall ◽  
Bos Indicus ◽  
High Capacity ◽  
Industrial Applications ◽  
Fibrobacter Succinogenes ◽  
Ruminococcus Flavefaciens ◽  
Ruminal Bacteria ◽  
Tropical Conditions ◽  
Pure Cultures

<p>The capacity to degrade the cellular wall of Bouteloua repens of 12 isolates of Ruminococcus flavefaciens and 17 isolates of Fibrobacter succinogenes was determined. A procedure was developed to standardize both, the inoculum and the substrate concentration for in vitro incubations of pure culture isolates.The ruminal bacteria were isolated from either Bos indicus cattle from the Alto Magdalena region of Colombia, grazing Bouteloua repens, and Sanmartinero cows (a Colombian criollo breed) from the  eastern lowlands (Llanos Orientales) of Colombia, grazing Brachiara spp. The isolates identity was confirmed using molecular methods. All isolates of F. succinogenes showed a high capacity to degrade cell wall preparations of Bouteloua repens, than those of R. flavefaciens (P&lt;0.0001).The effect of individual isolated on cell wall digestibility was also highly significant (P&lt;0.0001). Native isolates surpassed considerably the reference strains of R. flavefaciens ATCC 19208 (12.83% vs. 6.83%) and F. succinogenes ATCC 19169 (13.77% vs. 7.94%) on their capacity to digest Bouteloua repens cellular wall.This difference was highly significant (p&lt;0.05) for all isolates. Findings suggest that in tropical conditions native ruminal bacteria has developed a high capacity to degrade lignocellulose. Further research about the potential usefulness of specific inocula or enzyme extracts developed from such isolates in improving the degradability of low quality forages by cattle or what industrial applications can be improved by the use of these products.</p><p><em><br /></em></p><p><strong>Degradación in vitro de </strong><strong><em>Bouteloua repens </em></strong><strong>por cultivos de </strong><strong><em>R. flavefaciens </em></strong><strong>y </strong><strong><em>F. succinogenes </em></strong><strong>aislados de ganado alimentado con pastos tropicales en Colombia</strong></p><p>Se determinó la capacidad de degradación de la pared celular de <em>Bouteloua repens </em>de 12 aislados de <em>Ruminococcus flavefaciens </em>y 17 de <em>Fibrobacter succinogenes</em>. Se desarrolló un procedimiento para estandarizar la concentración, tanto del inóculo como de los sustratos, de las incubaciones <em>in vitro </em>de cultivos puros de los aislados. Las bactérias fueron aisladas del ganado <em>Bos indicus</em>, procedente de la región del Alto Magdalena, que pastoreaban Teatino (<em>Bouteloua repens</em>) y del ganado Sanmartinero (una raza nativa) procedente de los Llanos Orientales de Colombia, que pastoreaban <em>Brachiaria spp</em>. La identificación del aislado fue confirmada usando métodos moleculares. Todos los aislados de <em>F. succinogenes </em>mostraron mayor capacidad de degradación de las preparaciones de pared celular de <em>Bouteloua repens </em>que los de <em>R. flavefaciens </em>(P&lt;0.0001). La capacidad de los aislados individuales para degradar la pared celular también difirió significativamente (P&lt;0.0001). Los aislados nativos sobrepasaron considerablemente la capacidad para digerir la pared celular de <em>Bouteloua repens </em>de las cepas de referencia de <em>R. flavefaciens</em>ATCC19208 (12.83% vs. 6.83%) y <em>F. succinogenes </em>ATCC19169 (13.77% vs. 7.94%), diferencia que fue altamente significativa (p&lt;0.05) para todos los aislados. Los resultados sugieren que, en condiciones tropicales, las bacterias ruminales nativas tienen una alta capacidad para degradar la lignocelulosa. Se requiere mayor investigación sobre la utilidad potencial del inóculo o de extractos enzimáticos desarrollados a partir de tales aislados, a fin de aumentar la degradabilidad por el ganado de forrajes de baja calidad o para definir las aplicaciones industriales pueden ser mejoradas por el uso de estos productos.</p><p> </p>

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