scholarly journals Characterization of Four Outer Membrane Proteins Involved in Binding Starch to the Cell Surface ofBacteroides thetaiotaomicron

2000 ◽  
Vol 182 (19) ◽  
pp. 5365-5372 ◽  
Author(s):  
Joseph A. Shipman ◽  
James E. Berleman ◽  
Abigail A. Salyers
Keyword(s):  
Membrane Proteins ◽  
Cell Surface ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Binding Activity ◽  
Obligate Anaerobe ◽  
Binding Assays ◽  
Starch Utilization

ABSTRACT Bacteroides thetaiotaomicron, a gram-negative obligate anaerobe, utilizes polysaccharides by binding them to its cell surface and allowing cell-associated enzymes to hydrolyze them into digestible fragments. We use the starch utilization system as a model to analyze the initial steps involved in polysaccharide binding and breakdown. In a recent paper, we reported that one of the outer membrane proteins involved, SusG, had starch-degrading activity but was not sufficient for growth on starch. Moreover, SusG alone did not have detectable starch binding activity. Previous studies have shown that starch binding is essential for starch utilization. In this paper, we report that four other outer membrane proteins, SusC through SusF, are responsible for starch binding. Results of 14C-starch binding assays show that SusC and SusD both contribute a significant amount of starch binding. SusE also appears to contribute substantially to starch binding. Using affinity chromatography, we show in vitro that these Sus proteins interact to bind starch. Moreover, protease accessibility of either SusC or SusD greatly increased when one was expressed without the other. This finding supports the hypothesis that SusC and SusD interact in the outer membrane. Evidence from additional protease accessibility studies suggests that SusC, SusE, and SusF are exposed on the cell surface. Our results demonstrate that SusC and SusD act as the major starch binding proteins on the cell surface, with SusE enhancing binding. SusF's role in starch utilization has yet to be determined, although the fact that starch protected it from proteolytic attack suggests that it does bind starch.

scholarly journals Isolation and characterization of outer membrane proteins (OMPs) from Salmonella Gallinarum in chicken and antibiogram of the isolates

2016 ◽  
Vol 8 (4) ◽  
pp. 2292-2297
Author(s):  
Asma Ul Husna ◽  
Shabir Ahmad Mir ◽  
Rusheeba Manzoor ◽  
Farhat Pandit ◽  
Shakil Ahmad Wani ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Antimicrobial Agents ◽  
Outer Membrane Proteins ◽  
Specific Detection ◽  
Salmonella Gallinarum ◽  
Isolation And Characterization ◽  
Faecal Samples

Salmonella isolates should be distinguished as it may assist in tracing the source of an outbreak and monitoring trends in antimicrobial resistance associated with a particular type. The specific detection of these Salmonella serotypes is therefore extremely important in order to attribute an isolate to a previously known epidemic outbreak. The present investigation was to isolate and identify S. Gallinarum, to study variation in the profile of outer membrane proteins (OMPs) and to determine in vitro antibiogram of S. Gallinarum in poultry. A total of 228 faecal samples and 22 visceral samples suspected for Salmonellosis were collected, of these 15 samples (6.0%) were found positive for S. Gallinarum. In the present study, rfbS gene sequence was helpful in the serotype-specific detection of S. Gallinarum giving a 187 bp product. Salmonella Gallinarum crude protein extracts determined by SDSPAGE showed migration of OMPs as several bands at approximate moleculer weights of appx. 45 kDa, 55 kDa, 64 kDa, 65 kDa, 74 kDa, 110 kDa, 120 kDa, 135 kDa, 150 kDa,155 kDa, 200 kDa and above 200 kDa. The study indicated a definite variation in the profile of OMPs of various Salmonella Gallinarum strains with major OMPs in the range of appx 80-100 kDa which could be the target for vaccine production. All the isolates tested against 14 antimicrobial agents showed variable susceptibility pattern with highest resistance to nalidixic acid, ampicillin and sulphadiazine and sensitivity to chloramphenicol, gentamicin and enrofloxacin.

scholarly journals Proteins Released by Helicobacter pylori In Vitro

2002 ◽  
Vol 184 (22) ◽  
pp. 6155-6162 ◽  
Author(s):  
Nayoung Kim ◽  
David L. Weeks ◽  
Jai Moo Shin ◽  
David R. Scott ◽  
Mary K. Young ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Membrane Proteins ◽  
Dna Binding ◽  
Outer Membrane ◽  
Nalidixic Acid ◽  
Outer Membrane Proteins ◽  
Gastric Epithelium ◽  
Synthesis Inhibitor ◽  
Vitro Analysis

ABSTRACT Secretion of proteins by Helicobacter pylori may contribute to gastric inflammation and epithelial damage. An in vitro analysis was designed to identify proteins released by mechanisms other than nonspecific lysis. The radioactivity of proteins in the supernatant was compared with that of the intact organism by two-dimensional gel phosphorimaging following a 4-h pulse-chase. The ratio of the amount of UreB, a known cytoplasmic protein, in the supernatant to that in the pellet was found to be 0.25, and this was taken as an index of lysis during the experiments (n = 6). Ratios greater than that of UreB were used to distinguish proteins that were selectively released into the medium. Thus, proteins enriched more than 10-fold in the supernatant compared to UreB were identified by mass spectrometry. Sixteen such proteins were present in the supernatant: VacA; a conserved secreted protein (HP1286); putative peptidyl cis-trans isomerase (HP0175); six proteins encoded by HP0305, HP0231, HP0973, HP0721, HP0129, and HP0902; thioredoxin (HP1458); single-stranded-DNA-binding 12RNP2 precursor (HP0827); histone-like DNA-binding protein HU (HP0835); ribosomal protein L11 (HP1202); a putative outer membrane protein (HP1564); and outer membrane proteins Omp21 (HP0913) and Omp20 (HP0912). All except HP0902, thioredoxin, HP0827, HP0835, and HP1202 had a signal peptide. When nalidixic acid, a DNA synthesis inhibitor, was added to inhibit cell division but not protein synthesis, to decrease possible contamination due to outer membrane shedding, two outer membrane proteins (Omp21 and Omp20) disappeared from the supernatant, and the amount of VacA also decreased. Thus, 13 proteins were still enriched greater than 10-fold in the medium after nalidixic acid treatment, suggesting these were released specifically, possibly by secretion. These proteins may be implicated in H. pylori-induced effects on the gastric epithelium.

scholarly journals Localized adherence by enteropathogenic Escherichia coli is an inducible phenotype associated with the expression of new outer membrane proteins.

1991 ◽  
Vol 174 (5) ◽  
pp. 1167-1177 ◽  
Author(s):  
J Vuopio-Varkila ◽  
G K Schoolnik
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
De Novo ◽  
Outer Membrane Proteins ◽  
Temporal Correlation ◽  
Enteropathogenic Escherichia Coli ◽  
E Coli

Enteropathogenic Escherichia coli grow as discrete colonies on the mucous membranes of the small intestine. A similar pattern can be demonstrated in vitro; termed localized adherence (LA), it is characterized by the presence of circumscribed clusters of bacteria attached to the surfaces of cultured epithelial cells. The LA phenotype was studied using B171, an O111:NM enteropathogenic E. coli (EPEC) strain, and HEp-2 cell monolayers. LA could be detected 30-60 min after exposure of HEp-2 cells to B171. However, bacteria transferred from infected HEp-2 cells to fresh monolayers exhibited LA within 15 min, indicating that LA is an inducible phenotype. Induction of the LA phenotype was found to be associated with de novo protein synthesis and changes in the outer membrane proteins, including the production of a new 18.5-kD polypeptide. A partial NH2-terminal amino acid sequence of this polypeptide was obtained and showed it to be identical through residue 12 to the recently described bundle-forming pilus subunit of EPEC. Expression of the 18.5-kD polypeptide required the 57-megadalton enteropathogenic E. coli adherence plasmid previously shown to be required for the LA phenotype in vitro and full virulence in vivo. This observation, the correspondence of the 18.5-kD polypeptide to an EPEC-specific pilus protein, and the temporal correlation of its expression with the development of the LA phenotype suggest that it may contribute to the EPEC colonial mode of growth.

scholarly journals Catecholamine-Modulated Novel Surface-Exposed Adhesin LIC20035 ofLeptospiraspp. Binds Host Extracellular Matrix Components and Is Recognized by the Host during Infection

2017 ◽  
Vol 84 (6) ◽  
Author(s):  
Karukriti Kaushik Ghosh ◽  
Aman Prakash ◽  
Vinayagamurthy Balamurugan ◽  
Manish Kumar
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Membrane Surface ◽  
Outer Membrane Proteins ◽  
Extracellular Matrices ◽  
Content Type ◽  
Extracellular Matrix Components ◽  
Gene Transcripts ◽  
Host Tissues

ABSTRACTIn this study, the effect of the host stress hormone catecholamine onLeptospiragene transcripts encoding outer membrane proteins was investigated. There was no impact of catecholamine supplementation on thein vitrogrowth pattern ofLeptospira interrogans; however, 7 genes out of 41 were differentially transcribed, and the effect was reversed to the basal level in the presence of the antagonist propranolol. Comprehensive analysis of one of the differentially regulated proteins, LIC20035 (in serovar Copenhageni)/LB047 (in serovar Lai) (due to catecholamine supplementation), revealed immunogenicity and ability to adhere to host extracellular matrices. Protease accessibility assay and phase partition of integral membrane proteins ofLeptospirashowed LIC20035/LB047 to be an outer membrane surface-exposed protein. The recombinant LIC20035 protein can be serologically detected using human/bovine sera positive for leptospirosis. Moreover, the recombinant LIC20035 can bind to diverse host extracellular matrices, with a higher affinity toward collagen and chondroitin sulfate.IMPORTANCELeptospirosis is a neglected tropical disease of global importance. This study aimed to identify outer membrane proteins of pathogenicLeptospiraresponding to host chemical signals like catecholamines, with the potential to serve as virulence factors, new serodiagnostic antigens, and vaccine candidates. This study mimicked the plausible means by whichLeptospiraduring infection and hormonal stress intercepts host catecholamines to disseminate in host tissues.

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