scholarly journals Phenylacetic and Phenylpropionic Acids Do Not Affect Xylan Degradation by Ruminococcus albus

2003 ◽  
Vol 69 (11) ◽  
pp. 6954-6958 ◽  
Author(s):  
Carine Reveneau ◽  
Sarah E. Adams ◽  
M. A. Cotta ◽  
M. Morrison
Keyword(s):  
Growth Medium ◽  
Cellulose Degradation ◽  
Xylanase Activity ◽  
Ruminococcus Albus ◽  
Carbohydrate Source ◽  
Ruminal Fluid ◽  
Xylan Degradation ◽  
Multiple Strains

ABSTRACT Since the addition of either ruminal fluid or a combination of phenylacetic and phenylpropionic acids (PAA/PPA) has previously been shown to dramatically improve cellulose degradation and growth of Ruminococcus albus, it was of interest to determine the effects of these additives on xylan-grown cultures. Although cell-bound xylanase activity increased when either PAA/PPA or ruminal fluid was added to the growth medium, total xylanase did not change, and neither of these supplements affected the growth or xylan-degrading capacity of R. albus 8. Similarly, neither PAA/PPA nor ruminal fluid affected xylan degradation by multiple strains of R. albus when xylan prepared from oat spelts was used as a carbohydrate source. These results show that the xylanolytic potential of R. albus is not conditional on the availability of PAA/PPA or other components of ruminal fluid.

Influence of carbohydrates on cell properties of Lactobacillus rhamnosus

2010 ◽  
Vol 5 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Jelena Begovic ◽  
Djordje Fira ◽  
Amarela Terzic-Vidojevic ◽  
Ljubisa Topisirovic
Keyword(s):  
Growth Medium ◽  
Lactobacillus Rhamnosus ◽  
Cell Surface Hydrophobicity ◽  
Protein Composition ◽  
Surface Hydrophobicity ◽  
Cellular Level ◽  
Medium Composition ◽  
Producer Strain ◽  
Carbohydrate Source ◽  
Complex Relationships

AbstractLactobacilli represent normal commensals of the human body, particularly in the gut and vagina where they protect these environments from incoming pathogens via a variety of mechanisms. The influence of the carbohydrate source present in reconstituted MRS growth medium on the different cell properties of two Lactobacillus rhamnosus strains were examined. Two human vaginal isolates, BGHV719 and exopolysaccharide producer strain BGHV954 were analyzed. The results demonstrated that unlike in reconstituted MRS with glucose as a carbon source, the presence of fructose, mannose, or rhamnose, significantly reduced cell surface hydrophobicity of both strains. In addition, differences in cell wall protein composition of L. rhamnosus BGHV719 and alterations in colony mucoidity of L. rhamnosus BGHV954 were also demonstrated. Light and SEM microscopy revealed differences on the cellular level when BGHV719 was cultivated in the presence of different sugars. The results of this study point out the importance of complex relationships between growth medium composition and the different aspects of bacterial behavior, and call for more detailed analyses of versatile bacterial responses to the changes in the environment, including vaginal ecosystem. This is especially important since lactobacilli are amongst the most widely used of probiotics.

scholarly journals Cellulose- and Xylan-Degrading Thermophilic Anaerobic Bacteria from Biocompost

2011 ◽  
Vol 77 (7) ◽  
pp. 2282-2291 ◽  
Author(s):  
M. V. Sizova ◽  
J. A. Izquierdo ◽  
N. S. Panikov ◽  
L. R. Lynd
Keyword(s):  
Enrichment Culture ◽  
Cellulose Degradation ◽  
Phylogenetic Analyses ◽  
Glycosyl Hydrolase ◽  
Anaerobic Bacteria ◽  
Xylanase Activity ◽  
Cellulase Activity ◽  
Lag Phase ◽  
Fermentation Products ◽  
Clostridium Clariflavum

ABSTRACTNine thermophilic cellulolytic clostridial isolates and four other noncellulolytic bacterial isolates were isolated from self-heated biocompost via preliminary enrichment culture on microcrystalline cellulose. All cellulolytic isolates grew vigorously on cellulose, with the formation of either ethanol and acetate or acetate and formate as principal fermentation products as well as lactate and glycerol as minor products. In addition, two out of nine cellulolytic strains were able to utilize xylan and pretreated wood with roughly the same efficiency as for cellulose. The major products of xylan fermentation were acetate and formate, with minor contributions of lactate and ethanol. Phylogenetic analyses of 16S rRNA and glycosyl hydrolase family 48 (GH48) gene sequences revealed that two xylan-utilizing isolates were related to aClostridium clariflavumstrain and represent a distinct novel branch within the GH48 family. Both isolates possessed high cellulase and xylanase activity induced independently by either cellulose or xylan. Enzymatic activity decayed after growth cessation, with more-rapid disappearance of cellulase activity than of xylanase activity. A mixture of xylan and cellulose was utilized simultaneously, with a significant synergistic effect observed as a reduction of lag phase in cellulose degradation.

scholarly journals Ruminococcus albus 8 Mutants Defective in Cellulose Degradation Are Deficient in Two Processive Endocellulases, Cel48A and Cel9B, Both of Which Possess a Novel Modular Architecture

2004 ◽  
Vol 186 (1) ◽  
pp. 136-145 ◽  
Author(s):  
Estelle Devillard ◽  
Dara B. Goodheart ◽  
Sanjay K. R. Karnati ◽  
Edward A. Bayer ◽  
Raphael Lamed ◽  
...  
Keyword(s):  
Glycoside Hydrolase ◽  
Sequence Data ◽  
Cellulose Degradation ◽  
Polyacrylamide Gel Electrophoresis ◽  
Glycoside Hydrolases ◽  
Cellulolytic Bacterium ◽  
Cellulolytic Bacteria ◽  
Modular Architecture ◽  
Ruminococcus Albus ◽  
Mutant Strains

ABSTRACT The cellulolytic bacterium Ruminococcus albus 8 adheres tightly to cellulose, but the molecular biology underpinning this process is not well characterized. Subtractive enrichment procedures were used to isolate mutants of R. albus 8 that are defective in adhesion to cellulose. Adhesion of the mutant strains was reduced 50% compared to that observed with the wild-type strain, and cellulose solubilization was also shown to be slower in these mutant strains, suggesting that bacterial adhesion and cellulose solubilization are inextricably linked. Two-dimensional polyacrylamide gel electrophoresis showed that all three mutants studied were impaired in the production of two high-molecular-mass, cell-bound polypeptides when they were cultured with either cellobiose or cellulose. The identities of these proteins were determined by a combination of mass spectrometry methods and genome sequence data for R. albus 8. One of the polypeptides is a family 9 glycoside hydrolase (Cel9B), and the other is a family 48 glycoside hydrolase (Cel48A). Both Cel9B and Cel48A possess a modular architecture, Cel9B possesses features characteristic of the B2 (or theme D) group of family 9 glycoside hydrolases, and Cel48A is structurally similar to the processive endocellulases CelF and CelS from Clostridium cellulolyticum and Clostridium thermocellum, respectively. Both Cel9B and Cel48A could be recovered by cellulose affinity procedures, but neither Cel9B nor Cel48A contains a dockerin, suggesting that these polypeptides are retained on the bacterial cell surface, and recovery by cellulose affinity procedures did not involve a clostridium-like cellulosome complex. Instead, both proteins possess a single copy of a novel X module with an unknown function at the C terminus. Such X modules are also present in several other R. albus glycoside hydrolases and are phylogentically distinct from the fibronectin III-like and X modules identified so far in other cellulolytic bacteria.

scholarly journals Cell Surface Enzyme Attachment Is Mediated by Family 37 Carbohydrate-Binding Modules, Unique to Ruminococcus albus

2008 ◽  
Vol 190 (24) ◽  
pp. 8220-8222 ◽  
Author(s):  
Anat Ezer ◽  
Erez Matalon ◽  
Sadanari Jindou ◽  
Ilya Borovok ◽  
Nof Atamna ◽  
...  
Keyword(s):  
Cell Surface ◽  
Bacterial Cell ◽  
Cellulose Degradation ◽  
Glycoside Hydrolases ◽  
Rumen Bacterium ◽  
Carbohydrate Binding ◽  
Ruminococcus Albus ◽  
System A ◽  
C Terminus ◽  
Carbohydrate Binding Modules

ABSTRACT The rumen bacterium Ruminococcus albus binds to and degrades crystalline cellulosic substrates via a unique cellulose degradation system. A unique family of carbohydrate-binding modules (CBM37), located at the C terminus of different glycoside hydrolases, appears to be responsible both for anchoring these enzymes to the bacterial cell surface and for substrate binding.

Rumen fermentation response to a direct-fed xylanase enzyme preparation from Thermomyces lanuginosus in sheep

2006 ◽  
Vol 54 (3) ◽  
pp. 333-342 ◽  
Author(s):  
V. Jurkovich ◽  
J. Kutasi ◽  
Hedvig Fébel ◽  
J. Reiczigel ◽  
E. Brydl ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Enzyme Preparation ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Xylanase Activity ◽  
Rumen Fermentation ◽  
Thermomyces Lanuginosus ◽  
Ruminal Fluid ◽  
Xylanase Enzyme ◽  
Fermentation Parameters

A study was conducted to obtain data on the effects of a fungal fibrolytic enzyme preparation (Rumino-zyme, with 250 FXU/g xylanase activities) from Thermomyces lanuginosus on some rumen fermentation parameters in sheep. Ruminal fluid samples were taken just before the morning feeding and then 2 h and 4 h after feeding. Xylanase activity, pH, concentration of ammonia and volatile fatty acids were measured. The enzyme supplementation did not affect the pH but increased the xylanase activity and the total VFA concentration of the rumen fluid. The molar proportion of acetate increased, propionate was not affected and butyrate decreased after enzyme administration. The concentration of ammonia also decreased after supplementation with the enzyme product. It can be concluded that the xylanase enzyme preparation from T. lanuginosus induced favourable changes in the major rumen fermentation parameters in sheep.

scholarly journals Carbohydrate and PepO control bimodality in competence development byStreptococcus mutans

2019 ◽  
Author(s):  
Simon A.M. Underhill ◽  
Robert C. Shields ◽  
Robert A. Burne ◽  
Stephen J. Hagen
Keyword(s):  
Growth Medium ◽  
Feedback Loop ◽  
Feedback System ◽  
Alternative Sigma Factor ◽  
Small Peptides ◽  
Carbohydrate Source ◽  
Genetic Competence ◽  
Mechanistic Insight ◽  
Defined Media ◽  
Insight Into

AbstractInStreptococcus mutans, the alternative sigma factor ComX controls entry into genetic competence. Competence signaling peptide (CSP) induces bimodal expression ofcomX, with only a fraction of cells in the population becoming transformable. Curiously, bimodalcomXactivation in response to CSP is affected by peptides in the growth medium and by carbohydrate source. CSP elicits bimodal expression ofcomXin media rich in small peptides, but in defined media lacking small peptides CSP induces no response incomX. In addition, growth on certain sugars other than glucose increases the proportion of the population that activatescomXin response to CSP, relative to growth on glucose. By investigating the connection between media and bimodalcomXexpression, we find evidence for two mechanisms that modulate transcriptional positive feedback in the ComRS system, which is the origin ofcomXbimodality. We find that the endopeptidase PepO suppresses the ComRS feedback loop, most likely by degrading the intracellular XIP/ComS signal. Deletion ofpepOeliminates bimodality incomX, leading to a unimodalcomXresponse to CSP in defined and complex media. We also find that CSP upregulatescomRin a carbohydrate source-dependent fashion, providing an additional stimulus to the ComRS feedback system. Our data provide mechanistic insight into how CSP regulates the bistable competence circuit and explain the puzzle of growth medium-dependence inS. mutanscompetence regulation.

Unraveling the xylanolytic potential of Acidobacteria bacterium AB60 from Cerrado soils

2020 ◽  
Vol 367 (18) ◽  
Author(s):  
Gisele Regina Rodrigues ◽  
Otávio Henrique Bezerra Pinto ◽  
Luís Felipe Schroeder ◽  
Gabriel da Rocha Fernandes ◽  
Ohana Yonara Assis Costa ◽  
...  
Keyword(s):  
Carboxymethyl Cellulose ◽  
Plant Cell Wall ◽  
Genomic Library ◽  
Cellulose Degradation ◽  
Open Reading Frames ◽  
Wall Material ◽  
Rrna Gene ◽  
Functional Screening ◽  
Glycosyl Hydrolases ◽  
Xylan Degradation

ABSTRACT The presence of genes for glycosyl hydrolases in many Acidobacteria genomes indicates an important role in the degradation of plant cell wall material. Acidobacteria bacterium AB60 was obtained from Cerrado oligotrophic soil in Brazil, where this phylum is abundant. The 16S rRNA gene analyses showed that AB60 was closely related to the genera Occallatibacter and Telmatobacter. However, AB60 grew on xylan as carbon source, which was not observed in Occallatibacter species; but growth was not detected on medium containing carboxymethyl cellulose, as observed in Telmatobacter. Nevertheless, the genome analysis of AB60 revealed genes for the enzymes involved in cellulose as well as xylan degradation. In addition to enzymes involved in xylan degradation, α-l-rhamnosidase was detected in the cultures of AB60. Functional screening of a small-insert genomic library did not identify any clones capable of carboxymethyl cellulose degradation, but open reading frames coding α-l-arabinofuranosidase and α-l-rhamnosidase were present in clones showing xylan degradation halos. Both enzymes act on the lateral chains of heteropolymers such as pectin and some hemicelluloses. These results indicate that the hydrolysis of α-linked sugars may offer a metabolic niche for slow-growing Acidobacteria, allowing them to co-exist with other plant-degrading microbes that hydrolyze β-linked sugars from cellulose or hemicellulose backbones.

scholarly journals Two Bifunctional β-Xylosidase /α-L-Arabinofuranosidases From GH43 With Different Structures in the xylan Degradation Strain of Paenibacillus Physcomitrellae XB Displayed the Similar xylo-oligosaccharides Degradation Ability

2021 ◽  
Author(s):  
Xiao Jie Zhang ◽  
Su Wang ◽  
Zhi Ling Chen ◽  
Yan Hong Li
Keyword(s):  
Metal Ions ◽  
Physcomitrella Patens ◽  
Beech Wood ◽  
Xylanase Activity ◽  
Genomic Analysis ◽  
Exchange Chromatography ◽  
Glycoside Hydrolase Family ◽  
Xylan Degradation ◽  
Degradation Ability ◽  
Xylosidase Activity

Abstract BackgroundThe strain Paenibacillus physcomitrellae XB isolated from moss of Physcomitrella patens was found have the xylan degradation ability, but its degradation characteristics and the related mechanism has not been revealed.ResultsIn this study, Paenibacillus physcomitrellae XB exhibited different xylan degradation ability under the different substrates of corncob xylan (CCX), oat spet xylan (OSX), wheat flour arabinoxylan (AX) and beech wood xylan (BWX). Genomic analysis showed that ~ 38 genes were related to xylan degradation, and quantitative real time RT-PCR showed that two glycoside hydrolase family 43 genes (Pph_0602 and Pph_2344) were up-regulated on 1% CCX and xylose. Substrate-specific experiments with purified proteins Ppxyl43A (Pph_0602) and Ppxyl43B (Pph_2344) revealed that both of them exhibited β-xylosidase activity toward chromogenic substrate p-nitrophenyl–D-xylopyranoside and α-L-arabinofuranosidase activity toward p-nitrophenyl-α-L-arabinofuranoside, indicating at least bifunctionality. Combined their degradation features on the natural substrates of different xylans with the hydrolytic products separated by thin-layer chromatography and high-performance anion exchange chromatography profiles, it was found that both Ppxyl43A and Ppxyl43B were with the similar degradation ability on xylo-oligosaccharides (like CCX, OSX, xylohexaose and xylobiose). Both of them even could hydrolyze xylohexaose and xylobiose completely to xylose, but could not hydrolyze BWX and AX to produce xylooligosaccharides or xylose, suggesting they have no endo-xylanase activity and mainly hydrolyze xylo-oligosaccharides by β-xylosidase activity. Moreover, the kinetic parameters of β-xylosidase and α-L-arabinofuranosidase of both two proteins indicated their affinity with all the detected natural substrate (CCX) and chromogenic substrates were nearly similar. In addition, despite having no signal peptides, both of them might export outside the cell by the nonconventional pathways. However, Ppxy143B exhibited wider temperature and pH ranges, higher pH and thermostability, and was less influenced by metal ions than Ppxyl43A. Given its enzymatic characteristics and predicted structure, it is likely that the C-terminus domain (GH43_C2) of Ppxyl43B enhances the stability of the two enzymes and also restricts the substrates’ or metal ions’ access to the active sites.ConclusionsPpxyl43A and Ppxyl43B were β-xylosidase/α-L-arabinofuranosidase bifunctional enzymes with different structures from Paenibacillus physcomitrellae XB and exhibited similar xylo-oligosaccharides hydrolyse ability, which would be useful in the further lignocellulosic biomass conversion.

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