scholarly journals Biosynthesis of 2-acetamido-2,6-dideoxy-l-hexoses in bacteria follows a pattern distinct from those of the pathways of 6-deoxy-l-hexoses

2003 ◽  
Vol 371 (3) ◽  
pp. 989-995 ◽  
Author(s):  
Bernd KNEIDINGER ◽  
Suzon LAROCQUE ◽  
Jean-Robert BRISSON ◽  
Nicolas CADOTTE ◽  
Joseph S. LAM
Keyword(s):  
Capillary Electrophoresis ◽  
General Feature ◽  
Specific Substrate ◽  
Gram Negative Bacteria ◽  
Reaction Products ◽  
Gram Negative ◽  
Common Precursor ◽  
The Common ◽  
Reaction Cascades ◽  
Stereospecific Reaction

6-Deoxy-l-hexoses have been shown to be synthesized from dTDP-d-glucose or GDP-d-mannose so that the gluco/galacto-configuration is converted into the manno/talo-configuration, and manno/talo is switched to gluco/galacto. Our laboratory has been investigating the biosynthesis of 2-acetamido-2,6-dideoxy-l-hexoses in both Gram-positive and Gram-negative bacteria, and in a recent paper we described the biosynthesis of the talo (pneumosamine) and galacto (fucosamine) derivatives from UDP-d-N-acetylglucosamine a 2-acetamido sugar [Kneidinger, O'Riordan, Li, Brisson, Lee and Lam (2003) J. Biol. Chem. 278, 3615–3627]. In the present study, we undertake the task to test the hypothesis that UDP-d-N-acetylglucosamine is the common precursor for the production of 2-acetamido-2,6-dideoxy-l-hexoses in the gluco-, galacto-, manno- and talo-configurations. We present data to reveal the steps for the biosynthesis of the gluco (quinovosamine)- and manno (rhamnosamine)-configured compounds. The corresponding enzymes WbvB, WbvR and WbvD from Vibrio cholerae serotype O37 have been overexpressed and purified to near homogeneity. The enzymic reactions have been analysed by capillary electrophoresis and NMR spectroscopy. Our data have revealed a general feature of reaction cascades due to the three enzymes. First, UDP-d-N-acetylglucosamine is catalysed by the multi-functional enzyme WbvB, whereby dehydration occurs at C-4, C-6 and epimerization at C-5, C-3 to produce UDP-2-acetamido-2,6-dideoxy-l-lyxo-4-hexulose. Secondly, this intermediate is converted by the C-4 reductase, WbvR, in a stereospecific reaction to yield UDP-2-acetamido-l-rhamnose. Thirdly, UDP-2-acetamido-l-rhamnose is epimerized at C-2 to UDP-2-acetamido-l-quinovose by WbvD. Interestingly, WbvD is also an orthologue of WbjD, but not vice versa. Incubation of purified WbvD with UDP-2-acetamido-2,6-dideoxy-l-talose and analysing the reaction products by capillary electrophoresis revealed the same product peak as when WbjD was used. This sugar nucleotide is a specific substrate for WbjD and is a C-4 epimer of UDP-2-acetamido-l-rhamnose.

Capillary electrophoresis for fast detection of heterogeneous population in colistin-resistant Gram-negative bacteria

2015 ◽  
Vol 36 (20) ◽  
pp. 2630-2633 ◽  
Author(s):  
Guillaume Sautrey ◽  
Raphaël E. Duval ◽  
Alicia Chevalley ◽  
Stéphane Fontanay ◽  
Igor Clarot
Keyword(s):  
Capillary Electrophoresis ◽  
Heterogeneous Population ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Fast Detection

Food-Grade Chemicals for Use in Designing Food Preservative Systems

1981 ◽  
Vol 44 (8) ◽  
pp. 633-647 ◽  
Author(s):  
JON J. KABARA
Keyword(s):  
Systems Approach ◽  
Sorbic Acid ◽  
Food Preservation ◽  
The Other ◽  
Gram Negative Bacteria ◽  
Biocidal Activity ◽  
Food Preservative ◽  
Gram Negative ◽  
Food Grade ◽  
The Common

Now that energy has become a world problem, cheap, effective chemical preservation is critical. This discussion forwards a new concept in food preservation. The concept is based on a ‘systems’ approach, using three common foodstuffs: monolaurin, food-grade phenolics and chelator, three multifunctional food materials, whose history as potential preservatives is reviewed. Although monolaurin (Lauricidin) is a Generally Recognized As Safe chemical, its use as part of a ‘preservative system’ is new. Comparisons of its germicidal activity by investigators have shown it to be more effective than proprionates, benzoates and even sorbic acid. The common antioxidants, tert-butylhydroxytoluene (BHT) or tert-butylhydroxyanisole (BHA) have been shown since 1967 to affect a number of different microorganisms, including viruses. The chelator ethylenediamineacetate (EDT A) has weak biocidal activity on its own but can potentiate the effect of the first two biocidal agents, particularly against gram-negative bacteria. The three common food chemicals therefore become part of a ‘preservative system’. The amount and ratio of one to the other is determined by the specific need for microbiological protection.

scholarly journals OBSERVATIONS ON THE GROWTH OF BACTERIA ON MEDIA CONTAINING VARIOUS ANILIN DYES

1914 ◽  
Vol 19 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Charles Krumwiede ◽  
Josephine S. Pratt
Keyword(s):  
Gentian Violet ◽  
The Other ◽  
Quantitative Character ◽  
Gram Negative Bacteria ◽  
Gram Stain ◽  
Specific Difference ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
The Common ◽  
Growth Of Bacteria

Gentian violet and allied anilin dyes have a similar influence on bacterial growth, dividing bacteria into two groups corresponding in general to their reaction to the Gram stain. Among Gram-negative bacteria a strain is occasionally encountered which will not grow on violet agar, differentiating it from other members of the same species or variety. The reaction is quantitative, although the quantitative character is more marked with some species than with others. The streptococcus-pneumococcus group differ from other Gram-positive bacteria in their ability to grow in the presence of amounts of dye sufficient to inhibit the other species. The dysentery bacillus group shows marked variation in the presence of dyes. In the case of fuchsin the variation approaches closely a specific difference between the dysentery and paradysentery groups. The variations of the latter groups with other dyes show no correlation with the common differential characteristics. A closer study might reveal variations in other characteristics which would parallel the different reactions to dyes. Decolorization with sodium sulphite robs the dyes of some of their inhibitive powers.

scholarly journals Isolation and Identification of Gram Positive and Negative Bacteria from Dairy Department Waste Lines at Baraton University

2020 ◽  
Author(s):  
Stella Wanyama
Keyword(s):  
Dairy Farm ◽  
Specific Substrate ◽  
Gram Negative Bacteria ◽  
Microbial Activities ◽  
Isolation And Identification ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Lactose Fermentation ◽  
Culture Characteristics

AbstractBaraton University dairy farm is an environment that attracts a microbiologist to inquire the composition of bacteria that exist there in. The knowledge of bacteria has in time and again amazed the life scientist community that have invested to acquire more information in this microbiology world.The study engages fundamental tests such as gram stain, endospore stain, and assays for specific microbial activities & enzymes, susceptibility on disinfectant and antibiotic, utilization of specific substrate and culture characteristics. The two organisms (gram negative and positive) tested positive for sucrose & lactose fermentation, Indole & Methly red, catalase & Oxidase, were both facultative and motile. On contrary, gram positive bacteria had spores and had a gamma haemolysis on Blood Agar, while gram negative bacteria haemolysed beta haemolysis. To draw a conclusion on the identity of the two organisms is that, the gram positive is a Bacillus ........ while gram negative is Escherichia coli.

scholarly journals Timber-colonizing gram-negative bacteria as potential causative agents of respiratory diseases in woodworkers

2022 ◽  
Author(s):  
Angelina Wójcik-Fatla ◽  
Barbara Mackiewicz ◽  
Anna Sawczyn-Domańska ◽  
Jacek Sroka ◽  
Jan Siwiec ◽  
...  
Keyword(s):  
Wood Dust ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Wood Processing ◽  
Causative Agents ◽  
Long Time ◽  
Speed Up ◽  
The Common ◽  
Organic Dust Toxic Syndrome ◽  
Radiographic Changes

Abstract Occurrence Gram-negative bacteria occur commonly in the inner tissues of stored coniferous and deciduous timber, showing a marked variation in numbers. The greatest maximal numbers are found in the sapwood of coniferous timber. The common constituents of the Gram-negative biota are potentially pathogenic species of Enterobacteriaceae family of the genera Rahnella, Pantoea, Enterobacter, and Klebsiella. The air of wood-processing facilities is polluted with the wood-borne Gram-negative bacteria and produced by them endotoxin, as demonstrated worldwide by numerous studies. Effects There are three potential pathways of the pathogenic impact of wood-borne Gram-negative bacteria on exposed woodworkers: allergic, immunotoxic, and infectious. Allergic impact has been underestimated for a long time with relation to Gram-negative bacteria. Hopefully, the recent demonstration of the first documented case of hypersensitivity pneumonitis (HP) in woodworkers caused by Pantoea agglomerans which developed in extremely large quantities in birch sapwood, would speed up finding of new wood-related cases of HP caused by Gram-negative bacteria. The second pathway is associated with endotoxin, exerting strong immunotoxic (excessively immunostimulative) action. It has been demonstrated that endotoxin is released into wood dust in the form of nano-sized microvesicles, by peeling off the outer membrane of bacteria. Endotoxin microvesicles are easily inhaled by humans together with dust because of small dimensions and aerodynamic shape. Afterwards, they cause a nonspecific activation of lung macrophages, which release numerous inflammatory mediators causing an inflammatory lung reaction, chest tightness, fever, gas exchange disorders, and bronchospasm, without radiographic changes. The resulting disease is known as “Organic Dust Toxic Syndrome” or “toxic pneumonitis.” The potential third pathway of pathogenic impact is infection. The suspected species is Klebsiella pneumoniae that may occur commonly in wood dust; however, until now this pathway has not been confirmed. Conclusion Summarizing, Gram-negative bacteria-inhabiting timber should be considered, besides filamentous fungi and actinobacteria, as important risk factors of occupational disease in woodworkers that could be either HP with allergenic background or toxic pneumonitis elicited by endotoxin.

Xeroxographic-assisted location of areas or structures on clinical slides for EM examination

1992 ◽  
Vol 50 (1) ◽  
pp. 770-771 ◽  
Author(s):  
Beverly L. Giammara ◽  
Jacob S. Hanker
Keyword(s):  
Light Microscopy ◽  
Basement Membranes ◽  
Type Iii Collagen ◽  
Gram Negative Bacteria ◽  
Reaction Products ◽  
Gram Negative ◽  
Type Iii ◽  
Immunocytochemical Reaction

Recent studies in our laboratories have resulted in the development of microwave-accelerated silver stains for the demonstration of basement membranes and fungi, gram-negative bacteria, type III collagen, endoneurium, perineurium, DNA, and DAB or PPD-PC cytochemical or immunocytochemical reaction products. We have also found that the very structure in a specimen that raised a question by light microscopy can be mapped with a Micro-Locator Slide and then located and examined by the SEI and BEI modes of SEM by the techniques collated in this summary.

Accumulation of incomplete metabolic side products of lipid A in Salmonella typhimurium during inhibition of 3-deoxy-D-manno-octulosonate incorporation by a new class of antibacterial agents

1989 ◽  
Vol 35 (6) ◽  
pp. 646-650 ◽  
Author(s):  
Sunil K. Kadam ◽  
Colette C. Doran ◽  
Robert C. Goldman
Keyword(s):  
Salmonella Typhimurium ◽  
Polar Lipid ◽  
Antibacterial Agents ◽  
Lipid A ◽  
Side Reaction ◽  
Gram Negative Bacteria ◽  
Reaction Products ◽  
Gram Negative ◽  
New Class ◽  
Rapid Accumulation

A new class of antibacterial agents for Gram-negative bacteria, rationally designed to inhibit the incorporation of 3-deoxy-D-manno-octulosonate into lipopolysaccharide (LPS), was recently reported. In Salmonella typhimurium, where the lipid A species are well characterised, it was previously demonstrated that the addition of a compound which inhibits the enzyme 3-deoxy-manno-octulosonate cytidylytransferase (CMP-KDO synthetase; EC 2.7.7.38) leads to rapid accumulation of lipid A derivatives. The major lipid A species, IVA (O-(2-amino-2-deoxy-β-D-glucopyranosyl)-(1-6)-2-amino-2-deoxy-α-D-glucose, acylated at positions 2, 3, 2′, 3′ with β-hydroxymyristoyl groups and bearing phosphates at positions 1 and 4′), was shown to be converted mainly to LPS by pulse-chase experiments in the absence of inhibitor. Labelled precursor (IVA) was also chased to other more polar lipid A derivatives. During chase in the presence of inhibitor, there was no conversion to LPS, while the major lipid A species was converted to the same polar lipid A derivatives as in chase without inhibitor. Our data indicate that despite the accumulation of several species of lipid A derivatives during inhibition of LPS synthesis, only IVA is destined for synthesis of mature LPS when LPS synthesis resumes. The more polar lipid A derivatives would thus represent aberrant side reaction products which occur when the pathway is inhibited.Key words: CMP-KDO synthetase, lipopolysaccharide synthesis, lipid A precursor, 3-deoxy-D-manno-octulosonate analogs.

scholarly journals Functional Expression of Enterobacterial O-Polysaccharide Biosynthesis Enzymes in Bacillus subtilis

2002 ◽  
Vol 68 (10) ◽  
pp. 4722-4730 ◽  
Author(s):  
Christina Schäffer ◽  
Thomas Wugeditsch ◽  
Paul Messner ◽  
Chris Whitfield
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Functional Expression ◽  
Gram Negative Bacteria ◽  
Reaction Products ◽  
Gram Negative ◽  
Polysaccharide Biosynthesis ◽  
Shuttle Vectors ◽  
E Coli

ABSTRACT The expression of heterologous bacterial glycosyltransferases is of interest for potential application in the emerging field of carbohydrate engineering in gram-positive organisms. To assess the feasibility of using enzymes from gram-negative bacteria, the functional expression of the genes wbaP (formerly rfbP), wecA (formerly rfe), and wbbO (formerly rfbF) from enterobacterial lipopolysaccharide O-polysaccharide biosynthesis pathways was examined in Bacillus subtilis. WbaP and WecA are initiation enzymes for O-polysaccharide formation, catalyzing the transfer of galactosyl 1-phosphate from UDP-galactose and N-acetylglucosaminyl 1-phosphate from UDP-N-acetylglucosamine, respectively, to undecaprenylphosphate. The WecA product (undecaprenylpyrophosphoryl GlcNAc) is used as an acceptor to which the bifunctional wbbO gene product sequentially adds a galactopyranose and a galactofuranose residue from the corresponding UDP sugars to form a lipid-linked trisaccharide. Genes were cloned into the shuttle vectors pRB374 and pAW10. In B. subtilis hosts, the genes were effectively transcribed under the vegII promoter control of pRB374, but the plasmids were susceptible to rearrangements and deletion. In contrast, pAW10-based constructs, in which genes were cloned downstream of the tet resistance cassette, were stable but yielded lower levels of enzyme activity. In vitro glycosyltransferase assays were performed in Escherichia coli and B. subtilis, using membrane preparations as sources of enzymes and endogenous undecaprenylphosphate as an acceptor. Incorporation of radioactivity from UDP-α-d-14C-sugar into reaction products verified the functionality of WbaP, WecA, and WbbO in either host. Enzyme activities in B. subtilis varied between 20 and 75% of those measured in E. coli.

Capillary-Electrophoresis Mass Spectrometry for the Detection of Carbapenemases in (Multi-)Drug-Resistant Gram-Negative Bacteria

2014 ◽  
Vol 86 (18) ◽  
pp. 9154-9161 ◽  
Author(s):  
Frank Fleurbaaij ◽  
Anthonius A. M. Heemskerk ◽  
Anne Russcher ◽  
Oleg I. Klychnikov ◽  
André M. Deelder ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Capillary Electrophoresis ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Gram Negative ◽  
Capillary Electrophoresis Mass Spectrometry

scholarly journals Phytochemical characterization, and antioxidant and antimicrobial activities of essential oil from leaves of the common sage Salvia officinalis L. from Abha, Saudi Arabia

2020 ◽  
Vol 14 (6) ◽  
pp. 261-270 ◽  
Author(s):  
Atef El Jery ◽  
Mudassir Hasan ◽  
Md Mamoon Rashid ◽  
Mohammed Khaloofah Al Mesfer ◽  
Mohd Danish ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Essential Oil ◽  
Radical Scavenging ◽  
Antibacterial Properties ◽  
Salvia Officinalis ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
The Common

AbstractBackgroundThe composition and activities of essential oil of common sage from Saudi Arabia have not yet been reported.ObjectivesTo analyze the composition and antibacterial and antioxidant activities of essential oil from leaves of the common sage Salvia officinalis L. from Abha, Saudi Arabia.MethodsEssential oil was extracted from the leaves of S. officinalis by hydrodistillation, and its composition was analyzed using gas chromatography and mass spectrometry. Phenolics and flavonoids were determined using gallic acid and quercetin standards. Antioxidant activity was determined using a 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. Activity against various gram-positive and gram-negative bacteria was determined by disk diffusion and microdilution.ResultsThe yield of essential oil was 3.24 ± 0.55% (w/dry weight). Major compounds identified were camphor (20.3%), 1,8-cineole (15.0%), α-thujone (14.9%), viridiflorol (9.9%), carvone (6.2%), and β-thujone (5.7%). Phenolic content was 134.3 ± 17.61 μg/mL and flavonoid content was 119.5 ± 18.75 μg/mL. Antioxidant IC50 was 970 ± 5.5 μg/mL. The highest gram-positive antibacterial activity was for Bacillus subtilis and the highest gram-negative activity was for Escherichia coli. Minimum inhibitory concentrations ranged from 62.2 ± 3.9 to 1398.1 ± 50.7 μg/mL for gram-positive bacteria and from 323.4 ± 69.5 to 968.4 ± 120.6 μg/mL for gram-negative bacteria. Minimum bactericidal concentrations ranged from 120.3 ± 7.6 to 1387.4 ± 161.8 μg/mL for gram-positive bacteria and from 386 ± 8.3 to 1225.2 ± 100.9 μg/mL for gram-negative bacteria.ConclusionsEssential oil of S. officinalis L. from Abha, Saudi Arabia, showed compositional, antioxidant, and antibacterial properties generally consistent with essential oil of S. officinalis L. from other locations as reported in the literature.

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