scholarly journals The molecular mechanism of N-acetylglucosamine side-chain attachment to the Lancefield group A Carbohydrate inStreptococcus pyogenes

2017 ◽  
Author(s):  
Jeffrey S. Rush ◽  
Rebecca J. Edgar ◽  
Pan Deng ◽  
Jing Chen ◽  
Haining Zhu ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Mass Spectrometry Analysis ◽  
Side Chain ◽  
Antigenic Determinants ◽  
Limited Attention ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Essential Components ◽  
Group A ◽  
Lancefield Group

AbstractIn many Lactobacillales species (i.e. lactic acid bacteria), peptidoglycan is decorated by polyrhamnose polysaccharides that are critical for cell envelope integrity and cell shape and also represent key antigenic determinants. Despite the biological importance of these polysaccharides, their biosynthetic pathways have received limited attention. The important human pathogen,Streptococcus pyogenes, synthesizes a key antigenic surface polymer—the Lancefield group A carbohydrate (GAC). GAC is covalently attached to peptidoglycan and consists of a polyrhamnose polymer, with N-acetylglucosamine (GlcNAc) side chains, which is an essential virulence determinant. The molecular details of the mechanism of polyrhamnose modification with GlcNAc are currently unknown. In this report, using molecular genetics, analytical chemistry and mass spectrometry analysis, we demonstrated that GAC biosynthesis requires two distinct undecaprenol-linked GlcNAc-lipid intermediates: GlcNAc-pyrophosphorylundecaprenol (GlcNAc-P-P-Und) produced by the GlcNAc-phosphate transferase GacO and GlcNAc-phosphate-undecaprenol (GlcNAc-P-Und) produced by the glycosyltransferase GacI. Further investigations revealed that the GAC polyrhamnose backbone is assembled on GlcNAc-P-P-Und. Our results also suggested that a GT-C glycosyltranferase, GacL, transfers GlcNAc from GlcNAc-P-Und to polyrhamnose. Moreover, GacJ, a small membrane-associated protein, formed a complex with GacI and significantly stimulated its catalytic activity. Of note, we observed that GacI homologs perform a similar function inStreptococcus agalactiaeandEnterococcus faecalis. In conclusion, the elucidation of GAC biosynthesis inS. pyogenesreported here enhances our understanding of how other Gram-positive bacteria produce essential components of their cell wall.

scholarly journals Determining the Different Mechanisms Used by Pseudomonas Species to Cope With Minimal Inhibitory Concentrations of Zinc via Comparative Transcriptomic Analyses

2020 ◽  
Vol 11 ◽  
Author(s):  
Lei Lei ◽  
Jiahui Chen ◽  
Weifang Liao ◽  
Pulin Liu
Keyword(s):  
Cell Envelope ◽  
Acid Synthesis ◽  
Cell Permeability ◽  
Mass Spectrometry Analysis ◽  
Transcriptional Level ◽  
Type Vi Secretion System ◽  
Amino Acid Synthesis ◽  
Minimal Inhibitory Concentrations ◽  
Spectrometry Analysis ◽  
High Zinc

Pseudomonas is one of the most diverse bacterial genera identified in the environment. Genome sequence analysis has indicated that this genus can be clustered into three lineages and ten groups. Each group can adopt different mechanisms to thrive under zinc-depleted or high-zinc conditions, two environments that are frequently encountered during their environmental propagation. The response of three prominent Pseudomonas strains (Pseudomonas aeruginosa PAO1, Pseudomonas putida KT2440, and Pseudomonas fluorescens ATCC 13525T) to minimal inhibitory concentrations of zinc were compared using RNA-seq and ultra-performance liquid chromatography–tandem mass spectrometry analysis. Results demonstrated that the three strains shared only minimal similarity at the transcriptional level. Only four genes responsible for zinc efflux were commonly upregulated. P. aeruginosa PAO1 specifically downregulated the operons involved in siderophore synthesis and the genes that encode ribosomal protein, while upregulated the genes associated with antibiotic efflux and cell envelope biosynthesis. The membrane transporters in P. putida KT2440 were globally downregulated, indicating changes in cell permeability. Compared with P. aeruginosa PAO1 and P. putida KT2440, the most remarkable transcriptional variation in P. fluorescens ATCC 13525T is the significant downregulation of the type VI secretion system. Metabolite quantitative analysis showed that low concentrations of the metabolites involved in central carbon metabolism and amino acid synthesis were detected in the three strains. In summary, the cellular responses of the three strains under high-zinc condition is quite divergent. Although similar metal efflux systems were upregulated, the three strains employed different pathways to reduce zinc intrusion. In addition, zinc treatment can increase the difficulties of scavenging P. aeruginosa from its colonization area, and reduce the competitiveness of P. fluorescens in microbiota.

scholarly journals Distribution and antimicrobial activity of lactic acid bacteria associated with lychee fruits

2020 ◽  
Vol 25 (6) ◽  
pp. 2079-2085
Author(s):  
LIN-HU NAN ◽  
◽  
YI-SHENG CHEN ◽  
HUI-CHUNG WU ◽  
YU-CHING SU ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
Novel Species ◽  
16S Rrna Gene Sequencing ◽  
Mass Spectrometry Analysis ◽  
Rrna Gene ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Rrna Gene Sequencing

Lychee is a popular fruit in China and southeastern Asia. Although it is very popular, the microbiota of lactic acid bacteria (LAB) associated with lychee remains poorly described. Lychee samples from seven different markets located in three cities in Taiwan were collected and a total of 104 LAB were isolated. Through RFLP analyses of 16S rDNA and rpoA genes for grouping and 16S rRNA gene sequencing, these isolates were finally divided into 6 groups (A to F). The most common genera of LAB in lychee samples were Weissella and Leuconostoc. Weissella confusa strain E was found to produce a bacteriocin active against Listeria monocytogenes and some other Gram-positive bacteria. Mass spectrometry analysis revealed the bacteriocin mass to be approximately 3426.77 Da, which is different to other known Weissella bacteriocins. In addition, strain MB7 included in the genus Leuconostoc was identified as potential novel species or subspecies on the basis of phylogenetic analysis of 16S rRNA, rpoA and pheS gene sequences. Thus, this is the first report describing the distribution and varieties of LAB associated with lychee fruits. In addition, one potential novel LAB species or subspecies and one potential novel bacteriocin were also reported in this study.

scholarly journals Phytochemistry, gas chromatography-mass spectrometry analysis and in vitro anti-bacterial activities of Desplatsia dewevrei (De Wild. & T. Durand)

2018 ◽  
Vol 5 (10) ◽  
pp. 373-404
Author(s):  
Oghale Ovuakporie-Uvo ◽  
MacDonald Idu ◽  
Anne O. Itemire
Keyword(s):  
Inhibitory Effect ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Useful Plants ◽  
Zone Of Inhibition ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Quantitative Analyses ◽  
Bacterial Effect

Phytochemicals have been reported to have direct and/or indirect influence on the antibacterial potentials of useful plants. The present study was aimed at determining the phyto-components by traditional methods and GC-MS analysis alongside testing the anti-bacterial activities of Desplatsia dewevrei leaves and fruits. The maceration of 500 g of Desplatsia dewevrei powder in methanol yielded 5.7 g of extract. Qualitatively coumarins were found to be richly present in the leaves while, quinones were most evidently present in the fruits of Desplatsia dewevrei. Quantitative analyses show that the phenolic and tannic acid contents of Desplatsia dewevrei may be the chief compounds responsible for the antibacterial activity of the plant. GC-MS results of Desplatsia dewevrei fruits and leaves respectively showed Gas Chromatograms having 33 and 63 peaks representing different phyto-compounds. Of the 33 and 63 phyto-compounds, Cyclohexanepropanol, alpha.,2,2,6-tetrame-thyl and Farnesyl bromide were recurrent at different retention time. Although Desplatsia dewevrei showed no zone of inhibition for gram negative bacteria, its inhibitory effect on gram positive bacteria is significant. In conclusion, D. dewevrei is a phytochemical rich plant. However, a further study on the anti-bacterial effect of Desplatsia dewevrei using solvent extracts other than methanol is recommended for future incorporation in drug development.

Protective effects ofMentha spicataagainst nicotine-induced toxicity in liver and erythrocytes of Wistar rats

2018 ◽  
Vol 43 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Anouar Ben Saad ◽  
Ilhem Rjeibi ◽  
Hichem Alimi ◽  
Sana Ncib ◽  
Talel Bouhamda ◽  
...  
Keyword(s):  
Wistar Rats ◽  
White Blood Cells ◽  
Treated Group ◽  
Mass Spectrometry Analysis ◽  
Control Group ◽  
Protective Effects ◽  
Bioactive Substances ◽  
Mentha Spicata ◽  
Spectrometry Analysis ◽  
Group A

The aim of this study was to investigate the protective effect of Mentha spicata supplementation against nicotine-induced oxidative damage in the liver and erythrocytes of Wistar rats. Bioactive substances were determined by liquid chromatography – electrospray ionization – tandem mass spectrometry analysis. Animals were divided into 4 groups of 6 rats each: a normal control group, a nicotine-treated group (1 mg/kg), a group receiving M. spicata extract (100 mg/kg), and a group receiving both M. spicata extract (100 mg/kg) and nicotine (1 mg/kg). Many phenolic acids were identified in the M. spicata aqueous extract. After 2 months of treatment, nicotine induced an increase in the level of white blood cells and a marked decrease in erythrocytes, hemoglobin, and haematocrit. Aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase activities were also found to be higher in nicotine-treated group than those of the control group. Furthermore, nicotine-treated rats exhibited oxidative stress, as evidenced by a decrease in antioxidant enzymes activities and an increase in lipid peroxidation level in liver and erythrocytes. Interestingly, the oral administration of M. spicata extract by nicotine-treated rats alleviated such disturbances. M. spicata contained bioactive compounds that possess important antioxidant potential and protected liver and erythrocytes against nicotine-induced damage.

Antimicrobial characterization and safety aspects of the bacteriocinogenicEnterococcus hiraeF420 isolated from Moroccan raw goat milk

2012 ◽  
Vol 58 (5) ◽  
pp. 596-604 ◽  
Author(s):  
F. Achemchem ◽  
R. Cebrián ◽  
J. Abrini ◽  
M. Martínez-Bueno ◽  
E. Valdivia ◽  
...  
Keyword(s):  
Structural Gene ◽  
Food Systems ◽  
Goat Milk ◽  
Mass Spectrometry Analysis ◽  
Decarboxylase Activity ◽  
Strong Activity ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Naturally Occurring ◽  
Resistance To Heat

The F420 strain, isolated from raw goat milk and identified as Enterococcus hirae , was selected because of its strong activity against Gram-positive bacteria, including Listeria monocytogenes . Interestingly, the F420 strain lacks the virulence genes and decarboxylase activity of histidine, lysine, and ornithine, and it is susceptible to 11 of 14 tested antibiotics, including vancomycin. The antimicrobial compounds produced by E. hirae F420 strain showed high resistance to heat treatment and to acidic and basic pHs. The MALDI-TOF mass spectrometry analysis coupled with the sequence of peptide and structural gene analysis of one of the purified enterocins showed 100% identity with enterocin P (EntP), previously described in E. faecium strains. The structural gene for EntP is located on a plasmid of 65 kb. Other enterocins with molecular mass higher than 7 kDa were also detected. This is the first report of the production of EntP by E. hirae species naturally occurring in foods. The biotechnological characteristics of the F420 strain and its enterocins indicate their potential for application in the control of L. monocytogenes and other undesirable bacteria in food systems.

scholarly journals Profiling and tandem mass spectrometry analysis of aminoacylated phospholipids in Bacillus subtilis 

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 121 ◽  
Author(s):  
Metin Atila ◽  
Yu Luo
Keyword(s):  
Bacillus Subtilis ◽  
Mass Spectroscopy ◽  
High Sensitivity ◽  
Abundant Species ◽  
Mass Spectrometry Analysis ◽  
Bacterial Cells ◽  
Gram Positive ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Modern Mass

Cationic modulation of the dominantly negative electrostatic structure of phospholipids plays an important role in bacterial response to changes in the environment. In addition to zwitterionic phosphatidylethanolamine, Gram-positive bacteria are also abundant in positively charged lysyl-phosphatidylglycerol. Increased amounts of both types of lipids render Gram-positive bacterial cells more resistant to cationic antibiotic peptides such as defensins.  Lysyl and alanyl-phosphatidylglycerol as well as alanyl-cardiolipin have also been studied by mass spectroscopy. Phospholipids modified by other amino acids have been discovered by chemical analysis of the lipid lysate but have yet to be studied by mass spectroscopy. We exploited the high sensitivity of modern mass spectroscopy in searching for substructures in complex mixtures to establish a sensitive and thorough screen for aminoacylated phospholipids. The search for deprotonated aminoacyl anions in lipid extracted fromBacillus subtilisstrain 168 yielded strong evidence as well as relative abundance of aminoacyl-phosphatidylglycerols, which serves as a crude measure of the specificity of aminoacyl-phosphatidylglycerol synthase MprF. No aminoacyl-cardiolipin was found. More importantly, the second most abundant species in this category is D-alanyl-phosphatidylglycerol, suggesting a possible role in the D-alanylation pathway of wall- and lipo-teichoic acids.

scholarly journals Determining the different mechanisms used by Pseudomonas strains to cope with minimal inhibitory concentrations of zinc via comparative transcriptomic and metabolic analyses

2020 ◽  
Author(s):  
Pulin Liu ◽  
Jiahui Chen ◽  
Weifang Liao ◽  
Lihong Miao
Keyword(s):  
Cell Envelope ◽  
Cell Permeability ◽  
Mass Spectrometry Analysis ◽  
Clinical Samples ◽  
Transcriptional Level ◽  
Type Vi Secretion System ◽  
Amino Acid Synthesis ◽  
Minimal Inhibitory Concentrations ◽  
Spectrometry Analysis ◽  
High Zinc

Abstract Background Pseudomonas is one of the most diverse bacterial genera identified in soil, water, plants and clinical samples. Genome sequence analysis has indicated that this genus can be clustered into three lineages and ten groups. Each group can adopt different mechanisms to thrive under zinc-depleted or high-zinc conditions, two environments that are frequently encountered during their environmental propagation. Results The response mechanisms of three prominent Pseudomonas strains (Pseudomonas aeruginosa PAO1, Pseudomonas putida KT2440, and Pseudomonas fluorescence ATCC13525T) under high-zinc condition were compared using RNA-seq and ultra-performance liquid chromatography–tandem mass spectrometry analysis. Results demonstrated that the three strains shared only minimal similarity at the transcriptional level. Only four genes responsible for zinc efflux were commonly upregulated. P. aeruginosa PAO1 specifically downregulated the operons involved in siderophore synthesis and the genes that encode ribosomal protein, while upregulated the genes associated with antibiotic efflux and cell envelope biosynthesis. The membrane transporters in P. putida KT2440 were globally downregulated, indicating changes in cell permeability. Compared with P. aeruginosa PAO1 and P. putida KT2440, the most remarkable transcriptional variation in P. fluorescence ATCC13525 is the significant downregulation of the type VI secretion system. Metabolite quantitative analysis showed that low concentrations of the metabolites involved in central carbon metabolism and amino acid synthesis were detected in the three strains. Dipeptides containing branched-chain amino acids seems played an important role in alleviating stress caused by zinc ions. Conclusion The exclusion of cytoplasmic ions and reducing the intrusion of excess zinc are equally important for P. aeruginosa, P. putida, and P. fluorescence to withstand external zinc stress. Although similar metal efflux systems were commonly upregulated, these three strains apparently used different pathways to reduce zinc entry. In addition, zinc treatment can increase the difficulties of scavenging P. aeruginosa from its colonisation area, and reduce the effectiveness of P. fluorescence as a biocontrol agent.

scholarly journals Profiling and tandem mass spectrometry analysis of aminoacylated phospholipids in Bacillus subtilis 

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 121 ◽  
Author(s):  
Metin Atila ◽  
Yu Luo
Keyword(s):  
Bacillus Subtilis ◽  
Mass Spectroscopy ◽  
High Sensitivity ◽  
Abundant Species ◽  
Mass Spectrometry Analysis ◽  
Bacterial Cells ◽  
Gram Positive ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Modern Mass

Cationic modulation of the dominantly negative electrostatic structure of phospholipids plays an important role in bacterial response to changes in the environment. In addition to zwitterionic phosphatidylethanolamine, Gram-positive bacteria are also abundant in positively charged lysyl-phosphatidylglycerol. Increased amounts of both types of lipids render Gram-positive bacterial cells more resistant to cationic antibiotic peptides such as defensins.  Lysyl and alanyl-phosphatidylglycerol as well as alanyl-cardiolipin have also been studied by mass spectroscopy. Phospholipids modified by other amino acids have been discovered by chemical analysis of the lipid lysate but have yet to be studied by mass spectroscopy. We exploited the high sensitivity of modern mass spectroscopy in searching for substructures in complex mixtures to establish a sensitive and thorough screen for aminoacylated phospholipids. The search for deprotonated aminoacyl anions in lipid extracted fromBacillus subtilisstrain 168 yielded strong evidence as well as relative abundance of aminoacyl-phosphatidylglycerols, which serves as a crude measure of the specificity of aminoacyl-phosphatidylglycerol synthase MprF. No aminoacyl-cardiolipin was found. More importantly, the second most abundant species in this category is D-alanyl-phosphatidylglycerol, suggesting a possible role in the D-alanylation pathway of wall- and lipo-teichoic acids.

scholarly journals Sampling interstitial fluid from human skin using a microneedle patch

2020 ◽  
Vol 12 (571) ◽  
pp. eaaw0285
Author(s):  
Pradnya P. Samant ◽  
Megan M. Niedzwiecki ◽  
Nicholas Raviele ◽  
Vilinh Tran ◽  
Juan Mena-Lapaix ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Human Skin ◽  
Interstitial Fluid ◽  
Mass Spectrometry Analysis ◽  
Limited Attention ◽  
Spectrometry Analysis ◽  
Tissue Interstitial Fluid ◽  
Exogenous Compounds ◽  
Continuous Glucose Monitors ◽  
Microneedle Patch

Tissue interstitial fluid (ISF) surrounds cells and is an underutilized source of biomarkers that complements conventional sources such as blood and urine. However, ISF has received limited attention due largely to lack of simple collection methods. Here, we developed a minimally invasive, microneedle-based method to sample ISF from human skin that was well tolerated by participants. Using a microneedle patch to create an array of micropores in skin coupled with mild suction, we sampled ISF from 21 human participants and identified clinically relevant and sometimes distinct biomarkers in ISF when compared to companion plasma samples based on mass spectrometry analysis. Many biomarkers used in research and current clinical practice were common to ISF and plasma. Because ISF does not clot, these biomarkers could be continuously monitored in ISF similar to current continuous glucose monitors but without requiring an indwelling subcutaneous sensor. Biomarkers distinct to ISF included molecules associated with systemic and dermatological physiology, as well as exogenous compounds from environmental exposures. We also determined that pharmacokinetics of caffeine in healthy adults and pharmacodynamics of glucose in children and young adults with diabetes were similar in ISF and plasma. Overall, these studies provide a minimally invasive method to sample dermal ISF using microneedles and demonstrate human ISF as a source of biomarkers that may enable research and translation for future clinical applications.

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