scholarly journals MOLECULAR WEIGHT ANALYSIS OF PROTEIN UNITS IN THE VIBRIO CHOLERAE CELL ENVELOPE

1975 ◽  
Vol 21 (1) ◽  
pp. 61-63
Author(s):  
PRATIMA SUR ◽  
S. N. CHATTERJEE
Keyword(s):  
Molecular Weight ◽  
Vibrio Cholerae ◽  
Cell Envelope ◽  
Weight Analysis ◽  
Cholerae Cell

scholarly journals Temperate UV-Accelerated Weathering Cycle Combined with HT-GPC Analysis and Drop Point Testing for Determining the Environmental Instability of Polyethylene Films

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2373
Author(s):  
Celine Moreira ◽  
Richard Lloyd ◽  
Gavin Hill ◽  
Florence Huynh ◽  
Ana Trufasila ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Outdoor Exposure ◽  
Accelerated Weathering ◽  
Polyethylene Films ◽  
Parallel Testing ◽  
Mapping Analysis ◽  
Environmental Instability ◽  
Weight Analysis ◽  
Physical Changes ◽  
Ir Spectroscopic

Polyethylene films are one of the most frequently used packaging materials in our society, due to their combination of strength and flexibility. An unintended consequence of this high use has been the ever-increasing accumulation of polyethylene films in the natural environment. Previous attempts to understand their deterioration have either focused on their durability using polymer analysis; or they have focused on changes occurring during outdoor exposure. Herein, this study combines those strategies into one, by studying the chemical and physical changes in the polyethylene structure in a laboratory using molecular weight and IR spectroscopic mapping analysis, combined with temperate UV-accelerated weathering cycles. This approach has been correlated to real-world outdoor exposure timeframes by parallel testing of the sample polyethylene films in Florida and France. The formation of polyethylene microparticles or polyethylene waxes is elucidated through comparison of drop point testing and molecular weight analysis.

The outer membrane of Haemophilus influenzae type b: cell envelope associations of major proteins

1983 ◽  
Vol 29 (2) ◽  
pp. 280-287 ◽  
Author(s):  
J. W. Coulton ◽  
D. T. F. Wan
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Cell Envelope ◽  
Sodium Dodecyl ◽  
Haemophilus Influenzae Type ◽  
Major Protein ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Molecular Weights ◽  
Triton X

Membrane proteins fom the cell envelope of Haemophilus influenzae type b ATCC 9795 were examined by sodium dodecyl sulphate – polyacrylamide gel electrophoresis. When envelopes were extracted with a phosphate-based buffer containing 2% Triton X-100, a major protein of molecular weight 43 000 was detected in fractions containing cytoplasmic membrane proteins. The cell wall material which was Triton X-100 insoluble contained six major proteins of molecular weights 46 000, 40 000, 36 000, 30 000, 27 000, and 16 000. One of these proteins showed a shift in molecular weight from 27 000 to 36 000 when it was heated over a temperature range from 50 °C to 100 °C in buffer containing 2% sodium dodecyl sulphate, 5% 2-mercaptoethanol. This alteration in mobility could be demonstrated either by the membrane-bound form of the protein or by a detergent-soluble form of the protein. Enriched preparations of the 36 000 molecular weight form were obtained by a series of purification steps. Extraction of the Triton X-100 insoluble material with buffer containing 2% Triton X-100, 5.0 mM EDTA yielded chiefly one major protein molecular weight 30 000 and many minor protein species. Pretreatment of the Triton X-100 insoluble fraction with lysozyme followed by extraction with buffer containing 2% Triton X-100, 5.0 mM EDTA released two proteins of molecular weights 16 000 and 27 000 and few minor proteins. By these operational manipulations, the proteins of molecular weights 16 000 and 27 000 may be considered as peptidoglycan-associated proteins.

scholarly journals AVibrio choleraeBolA-Like Protein Is Required for Proper Cell Shape and Cell Envelope Integrity

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Aurore Fleurie ◽  
Abdelrahim Zoued ◽  
Laura Alvarez ◽  
Kelly M. Hines ◽  
Felipe Cava ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Cell Morphology ◽  
Cell Shape ◽  
Cell Envelope ◽  
Intestinal Colonization ◽  
Iron Sulfur Cluster ◽  
Content Type ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Morphological Defects

ABSTRACTBolA family proteins are conserved in Gram-negative bacteria and many eukaryotes. While diverse cellular phenotypes have been linked to this protein family, the molecular pathways through which these proteins mediate their effects are not well described. Here, we investigated the roles of BolA family proteins inVibrio cholerae, the cholera pathogen. LikeEscherichia coli,V. choleraeencodes two BolA proteins, BolA and IbaG. However, in marked contrast toE. coli, wherebolAis linked to cell shape andibaGis not, inV. cholerae,bolAmutants lack morphological defects, whereasibaGproved critical for the generation and/or maintenance of the pathogen’s morphology. Notably, the bizarre-shaped, multipolar, elongated, and wide cells that predominated in exponential-phase ΔibaGV. choleraecultures were not observed in stationary-phase cultures. TheV. choleraeΔibaGmutant exhibited increased sensitivity to cell envelope stressors, including cell wall-acting antibiotics and bile, and was defective in intestinal colonization. ΔibaGV. choleraehad reduced peptidoglycan and lipid II and altered outer membrane lipids, likely contributing to the mutant’s morphological defects and sensitivity to envelope stressors. Transposon insertion sequencing analysis ofibaG’s genetic interactions suggested thatibaGis involved in several processes involved in the generation and homeostasis of the cell envelope. Furthermore, copurification studies revealed that IbaG interacts with proteins containing iron-sulfur clusters or involved in their assembly. Collectively, our findings suggest thatV. choleraeIbaG controls cell morphology and cell envelope integrity through its role in biogenesis or trafficking of iron-sulfur cluster proteins.IMPORTANCEBolA-like proteins are conserved across prokaryotes and eukaryotes. These proteins have been linked to a variety of phenotypes, but the pathways and mechanisms through which they act have not been extensively characterized. Here, we unraveled the role of the BolA-like protein IbaG in the cholera pathogenVibrio cholerae. The absence of IbaG was associated with dramatic changes in cell morphology, sensitivity to envelope stressors, and intestinal colonization defects. IbaG was found to be required for biogenesis of several components of theV. choleraecell envelope and to interact with numerous iron-sulfur cluster-containing proteins and factors involved in their assembly. Thus, our findings suggest that IbaG governsV. choleraecell shape and cell envelope homeostasis through its effects on iron-sulfur proteins and associated pathways. The diversity of processes involving iron-sulfur-containing proteins is likely a factor underlying the range of phenotypes associated with BolA family proteins.

Accurate molecular weight analysis of histones using FFE and RP-HPLC on monolithic capillary columns

2009 ◽  
Vol 32 (15-16) ◽  
pp. 2691-2698 ◽  
Author(s):  
Evert-Jan Sneekes ◽  
Jun Han ◽  
Monica Elliot ◽  
Juan Ausio ◽  
Remco Swart ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Capillary Columns ◽  
Rp Hplc ◽  
Monolithic Capillary Columns ◽  
Weight Analysis

scholarly journals Reciprocal Regulation of Resistance-Nodulation-Division Efflux Systems and the Cpx Two-Component System in Vibrio cholerae

2014 ◽  
Vol 82 (7) ◽  
pp. 2980-2991 ◽  
Author(s):  
Dawn L. Taylor ◽  
X. Renee Bina ◽  
Leyla Slamti ◽  
Matthew K. Waldor ◽  
James E. Bina
Keyword(s):  
Antimicrobial Resistance ◽  
Vibrio Cholerae ◽  
Cell Envelope ◽  
Two Component System ◽  
Reciprocal Regulation ◽  
Component System ◽  
Content Type ◽  
Expression Of Genes ◽  
Two Component ◽  
Resistance Nodulation Division

ABSTRACTThe Cpx two-component regulatory system has been shown inEscherichia colito alleviate stress caused by misfolded cell envelope proteins. TheVibrio choleraeCpx system was previously found to respond to cues distinct from those in theE. colisystem, suggesting that this system fulfills a different physiological role in the cholera pathogen. Here, we used microarrays to identify genes that were regulated by theV. choleraeCpx system. Our observations suggest that the activation of theV. choleraeCpx system does not induce expression of genes involved in the mitigation of stress generated by misfolded cell envelope proteins but promotes expression of genes involved in antimicrobial resistance. In particular, activation of the Cpx system induced expression of the genes encoding the VexAB and VexGH resistance-nodulation-division (RND) efflux systems and their cognate outer membrane pore protein TolC. The promoters for these loci contained putative CpxR consensus binding sites, and ectopiccpxRexpression activated transcription from the promoters for the RND efflux systems. CpxR was not required for intrinsic antimicrobial resistance, but CpxR activation enhanced resistance to antimicrobial substrates of VexAB and VexGH. Mutations that inactivated VexAB or VexGH efflux activity resulted in the activation of the Cpx response, suggesting thatvexABandvexGHand thecpxP-cpxRAsystem are reciprocally regulated. We speculate that the reciprocal regulation of theV. choleraeRND efflux systems and the Cpx two-component system is mediated by the intracellular accumulation of an endogenously produced metabolic by-product that is normally extruded from the cell by the RND efflux systems.

scholarly journals Cell Envelope Perturbation Induces Oxidative Stress and Changes in Iron Homeostasis in Vibrio cholerae

2009 ◽  
Vol 191 (17) ◽  
pp. 5398-5408 ◽  
Author(s):  
Aleksandra E. Sikora ◽  
Sinem Beyhan ◽  
Michael Bagdasarian ◽  
Fitnat H. Yildiz ◽  
Maria Sandkvist
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Iron Homeostasis ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Genetic Alterations ◽  
Iron Storage ◽  
Study Gene Expression

ABSTRACT The Vibrio cholerae type II secretion (T2S) machinery is a multiprotein complex that spans the cell envelope. When the T2S system is inactivated, cholera toxin and other exoproteins accumulate in the periplasmic compartment. Additionally, loss of secretion via the T2S system leads to a reduced growth rate, compromised outer membrane integrity, and induction of the extracytoplasmic stress factor RpoE (A. E. Sikora, S. R. Lybarger, and M. Sandkvist, J. Bacteriol. 189:8484-8495, 2007). In this study, gene expression profiling reveals that inactivation of the T2S system alters the expression of genes encoding cell envelope components and proteins involved in central metabolism, chemotaxis, motility, oxidative stress, and iron storage and acquisition. Consistent with the gene expression data, molecular and biochemical analyses indicate that the T2S mutants suffer from internal oxidative stress and increased levels of intracellular ferrous iron. By using a tolA mutant of V. cholerae that shares a similar compromised membrane phenotype but maintains a functional T2S machinery, we show that the formation of radical oxygen species, induction of oxidative stress, and changes in iron physiology are likely general responses to cell envelope damage and are not unique to T2S mutants. Finally, we demonstrate that disruption of the V. cholerae cell envelope by chemical treatment with polymyxin B similarly results in induction of the RpoE-mediated stress response, increased sensitivity to oxidants, and a change in iron metabolism. We propose that many types of extracytoplasmic stresses, caused either by genetic alterations of outer membrane constituents or by chemical or physical damage to the cell envelope, induce common signaling pathways that ultimately lead to internal oxidative stress and misregulation of iron homeostasis.

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