scholarly journals Isolation and characterisation of ΦcrAss002, a crAss-like phage from the human gut that infects Bacteroides xylanisolvens

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Emma Guerin ◽  
Andrey N. Shkoporov ◽  
Stephen R. Stockdale ◽  
Joan Colom Comas ◽  
Ekaterina V. Khokhlova ◽  
...  
Keyword(s):  
Pure Culture ◽  
Faecal Sample ◽  
Healthy Donor ◽  
Liquid Culture ◽  
Metagenomic Data ◽  
Human Gut ◽  
Gram Negative ◽  
Liquid Cultures ◽  
Very High

Abstract Background The gut phageome comprises a complex phage community of thousands of individual strains, with a few highly abundant bacteriophages. CrAss-like phages, which infect bacteria of the order Bacteroidales, are the most abundant bacteriophage family in the human gut and make an important contribution to an individual’s core virome. Based on metagenomic data, crAss-like phages form a family, with four sub-families and ten candidate genera. To date, only three representatives isolated in pure culture have been reported: ΦcrAss001 and two closely related phages DAC15 and DAC17; all are members of the less abundant candidate genus VI. The persistence at high levels of both crAss-like phage and their Bacteroidales hosts in the human gut has not been explained mechanistically, and this phage-host relationship can only be properly studied with isolated phage-host pairs from as many genera as possible. Results Faeces from a healthy donor with high levels of crAss-like phage was used to initiate a faecal fermentation in a chemostat, with selected antibiotics chosen to inhibit rapidly growing bacteria and selectively enrich for Gram-negative Bacteroidales. This had the objective of promoting the simultaneous expansion of crAss-like phages on their native hosts. The levels of seven different crAss-like phages expanded during the fermentation, indicating that their hosts were also present in the fermenter. The enriched supernatant was then tested against individual Bacteroidales strains isolated from the same faecal sample. This resulted in the isolation of a previously uncharacterised crAss-like phage of candidate genus IV of the proposed Alphacrassvirinae sub-family, ΦcrAss002, that infects the gut commensal Bacteroides xylanisolvens. ΦcrAss002 does not form plaques or spots on lawns of sensitive cells, nor does it lyse liquid cultures, even at high titres. In keeping with the co-abundance of phage and host in the human gut, ΦcrAss002 and Bacteroides xylanisolvens can also co-exist at high levels when co-cultured in laboratory media. Conclusions We report the isolation and characterisation of ΦcrAss002, the first representative of the proposed Alphacrassvirinae sub-family of crAss-like phages. ΦcrAss002 cannot form plaques or spots on bacterial lawns but can co-exist with its host, Bacteroides xylanisolvens, at very high levels in liquid culture without impacting on bacterial numbers.

scholarly journals Massiliamide, a cyclic tetrapeptide with potent tyrosinase inhibitory properties from the Gram-negative bacterium Massilia albidiflava DSM 17472T

2020 ◽  
Author(s):  
Andri Frediansyah ◽  
Jan Straetener ◽  
Heike Brötz-Oesterhelt ◽  
Harald Gross
Keyword(s):  
Absolute Configuration ◽  
Inhibitory Activity ◽  
Liquid Culture ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Negative Bacterium ◽  
Gram Negative ◽  
The Absolute ◽  
Potent Inhibitory Activity ◽  
Cyclic Tetrapeptide

AbstractA cyclic tetrapeptide, designated massiliamide, was isolated from the liquid culture of the Gram-negative bacterium Massilia albidiflava DSM 17472T. The structure was elucidated through extensive spectroscopic analysis, including HR-MS and 1D and 2D NMR experiments. The absolute configuration was determined using the Marfey´s method. Massiliamide showed potent inhibitory activity towards tyrosinase with an IC50 value of 1.15 µM and no cytotoxicity.

scholarly journals Epidemiology and outcome of sepsis in a tertiary-care hospital in a developing country

2005 ◽  
Vol 134 (2) ◽  
pp. 315-322 ◽  
Author(s):  
M. D. TANRIOVER ◽  
G. S. GUVEN ◽  
D. SEN ◽  
S. UNAL ◽  
O. UZUN
Keyword(s):  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Clinical Approach ◽  
Gram Negative Bacteria ◽  
Care Hospital ◽  
Gram Negative ◽  
Mortality And Morbidity ◽  
Underlying Diseases ◽  
Major Pathogens ◽  
Very High

Sepsis continues to have a substantial mortality and morbidity despite advances in the diagnosis and management of this condition. We retrospectively analysed hospital charts of patients diagnosed to have sepsis between January 2002 and June 2003. Demographic characteristics of patients, microbiological findings and predictors of survival were evaluated. Sixty-nine sepsis episodes that occurred in 63 patients were analysed. The most common underlying diseases were hypertension, malignancies and diabetes mellitus. Renal insufficiency, respiratory distress and disseminated intravascular coagulation developed in 52·2, 30·4 and 30·4% of the episodes respectively; 47·7% of the blood cultures yielded an organism. Gram-negative bacteria were the predominant microorganisms (65·9%). Fifty-five patients (87·3%) died. Mechanical ventilation and underlying renal disease were significant determinants of mortality. In conclusion, Gram-negative bacteria remain the major pathogens in sepsis. The mortality remains very high, and a change in the clinical approach to the septic patient should be employed to improve the outcome.

scholarly journals Diversified mcr-1 -Harbouring Plasmid Reservoirs Confer Resistance to Colistin in Human Gut Microbiota

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Huiyan Ye ◽  
Yihui Li ◽  
Zhencui Li ◽  
Rongsui Gao ◽  
Han Zhang ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Multidrug Resistant ◽  
Global Public Health ◽  
Colistin Resistance ◽  
Human Gut ◽  
Gram Negative ◽  
Sequence Mapping ◽  
Human Gut Microbiota ◽  
Functional Analyses ◽  
Conventional Idea

ABSTRACT Colistin is an ultimate line of refuge against multidrug-resistant Gram-negative pathogens. Very recently, the emergence of plasmid-mediated mcr-1 colistin resistance has become a great challenge to global public health, raising the possibility that dissemination of the mcr-1 gene is underestimated and diversified. Here, we report three cases of plasmid-carried MCR-1 colistin resistance in isolates from gut microbiota of diarrhea patients. Structural and functional analyses determined that the colistin resistance is conferred purely by the single mcr-1 gene. Genetic and sequence mapping revealed that mcr-1 -harbouring plasmid reservoirs are present in diversity. Together, the data represent the first evidence of diversity in mcr-1 -harbouring plasmid reservoirs of human gut microbiota. IMPORTANCE The plasmid-mediated mobile colistin resistance gene ( mcr-1 ) challenged greatly the conventional idea mentioned above that colistin is an ultimate line of refuge against lethal infections by multidrug-resistant Gram-negative pathogens. It is a possibility that diversified dissemination of the mcr-1 gene might be greatly underestimated. We report three cases of plasmid-carried MCR-1 colistin resistance in isolates from gut microbiota of diarrhea patients and functionally define the colistin resistance conferred purely by the single mcr-1 gene. Genetic and sequence mapping revealed unexpected diversity among the mcr-1 -harbouring plasmid reservoirs of human gut microbiota.

scholarly journals Eight Gram-negative bacteria are 10 000 times more sensitive to cationic detergents than to anionic detergents

2003 ◽  
Vol 49 (12) ◽  
pp. 775-779 ◽  
Author(s):  
Soumitra Rajagopal ◽  
Nicole Eis ◽  
Kenneth W Nickerson
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Cetyltrimethylammonium Bromide ◽  
Liquid Culture ◽  
Sodium Dodecyl ◽  
Homoserine Lactone ◽  
Luria Bertani ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Cationic Detergents ◽  
Dodecyl Sulfate

In liquid culture, eight typical Gram-negative bacteria were ca. 10 000-fold more sensitive to cationic detergents than to the anionic detergent sodium dodecyl sulfate. Cetyltrimethylammonium bromide (CTAB) was inhibitory at concentrations ranging from 0.0006% to 0.01%. Four pseudomonads able to form biofilms were ca. 1000-fold more resistant to CTAB on Luria–Bertani agar plates than they were in liquid culture. A lasI mutant of Pseudomonas aerugi nosa was only able to tolerate 0.1% CTAB on Luria–Bertani agar plates but could tolerate 5% CTAB when supplemented with homoserine lactone containing culture supernatants.Key words: sodium dodecyl sulfate, cetyltrimethylammonium bromide, bacterial detergent resistance, homoserine lactones, Pseudomonas biofilms.

scholarly journals Detection of endotoxins with the Limulus test in burned and unburned mice infected with different species of gramnegative bacteria

1975 ◽  
Vol 75 (1) ◽  
pp. 99-112 ◽  
Author(s):  
R. J. Jones ◽  
E. A. Roe ◽  
R. E. Dyster
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Low Concentrations ◽  
High Concentrations ◽  
Very High ◽  
Limulus Test

SUMMARYThe Limulus test detected endotoxins in the plasma of burned and unburned mice infected with different species of gram-negative bacteria. Individual strains of different species of gram-negative bacteria produced different amounts of endotoxin in the plasma of infected mice. Plasma from mice given lethal infections showed very high concentrations of endotoxin. Low concentrations of endotoxin in the plasma were tolerated by mice but high concentrations were invariably fatal. A polyvalent pseudomonas vaccine reduced endotoxin in the plasma of mice given lethal infections of Pseudomonas aeruginosa.

scholarly journals Metagenomic data-mining reveals contrasting microbial populations responsible for trimethylamine formation in human gut and marine ecosystems

2016 ◽  
Vol 2 (9) ◽  
Author(s):  
Eleanor Jameson ◽  
Andrew C. Doxey ◽  
Ruth Airs ◽  
Kevin J. Purdy ◽  
J. Colin Murrell ◽  
...  
Keyword(s):  
Data Mining ◽  
Marine Ecosystems ◽  
Metagenomic Data ◽  
Microbial Populations ◽  
Human Gut

Description of bacteria able to degrade isoquinoline in pure culture

1994 ◽  
Vol 40 (7) ◽  
pp. 555-560 ◽  
Author(s):  
J. Aislabie ◽  
N. K. Richards ◽  
T. C. Lyttle
Keyword(s):  
Heterocyclic Compound ◽  
Pure Culture ◽  
Sole Source ◽  
Broth Culture ◽  
Gram Negative ◽  
Carbon And Nitrogen ◽  
The Family ◽  
Nitrogen Heterocyclic

Isoquinoline is a nitrogen heterocyclic compound that is associated with coal- and oil-derived wastes. Four strains of bacteria able to degrade isoquinoline in pure culture were isolated from sites known to be contaminated with oil. Isoquinoline was used as the sole source of carbon and nitrogen by these isolates. Isoquinoline was initially transformed to 1-hydroxyisoquinoline, which accumulated in the broth culture, and then disappeared. The four strains isolated were Gram negative, aerobic, rod-shaped bacteria with polar flagella. The strains have been presumptively identified as members of the family Comamonadaceae.Key words: isoquinoline degradation, Comamonadaceae.not available

AN ANTIBIOTIC-PRODUCING BACTERIUM OF THE GENUS PSEUDOMONAS

1954 ◽  
Vol 1 (2) ◽  
pp. 118-124 ◽  
Author(s):  
S. H. F. Chinn
Keyword(s):  
Pure Culture ◽  
Fusarium Culmorum ◽  
Antibiotic Activity ◽  
In Vitro Studies ◽  
Gram Positive ◽  
Gram Negative ◽  
Helminthosporium Sativum ◽  
Pathogenic Organisms

A Gram-negative rod, conforming; to Pseudomonas viscosa (Frankland and Frankland) Migula, was isolated in practically pure culture from a sample of wheat that did not show the usual mixture of epiphytes. In vitro studies revealed an unusual antibiotic spectrum against a variety of Gram-positive and -negative bacteria as well as against Helminthosporium sativum and Fusarium culmorum. Comparative.studies of the organism and P. aeruginosa, P. fluorescens, and P. chlororaphis indicated that it possessed greater antibiotic activity than any of these three species of Pseudomonas. Application to the control of some plant pathogenic organisms is suggested.

scholarly journals Gut SymbiontBacteroides fragilisSecretes a Eukaryotic-Like Ubiquitin Protein That Mediates Intraspecies Antagonism

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Maria Chatzidaki-Livanis ◽  
Michael J. Coyne ◽  
Kevin G. Roelofs ◽  
Rahul R. Gentyala ◽  
Jarreth M. Caldwell ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Bacteroides Fragilis ◽  
Signal Peptidase ◽  
Metagenomic Data ◽  
Antimicrobial Protein ◽  
Secretion Systems ◽  
Human Gut ◽  
Gene Encoding ◽  
Toxic Activity ◽  
Signal Peptidase I

ABSTRACTHuman gutBacteroidesspecies produce different types of toxins that antagonize closely related members of the gut microbiota. Some are toxic effectors delivered by type VI secretion systems, and others are non-contact-dependent secreted antimicrobial proteins. Many strains ofBacteroides fragilissecrete antimicrobial molecules, but only one of these toxins has been described to date (Bacteroidalessecreted antimicrobial protein 1 [BSAP-1]). In this study, we describe a novel secreted protein produced byB. fragilisstrain 638R that mediated intraspecies antagonism. Using transposon mutagenesis and deletion mutation, we identified a gene encoding a eukaryotic-like ubiquitin protein (BfUbb) necessary for toxin activity against a subset ofB. fragilisstrains. The addition ofubbinto a heterologous background strain conferred toxic activity on that strain. We found this gene to be one of the most highly expressed in theB. fragilisgenome. The mature protein is 84% similar to human ubiquitin but has an N-terminal signal peptidase I (SpI) signal sequence and is secreted extracellularly. We found that the mature 76-amino-acid synthetic protein has very potent activity, confirming that BfUbb mediates the activity. Analyses of human gut metagenomic data sets revealed thatubbis present in 12% of the metagenomes that have evidence ofB. fragilis. As 638R produces both BSAP-1 and BfUbb, we performed a comprehensive analysis of the toxin activity of BSAP-1 and BfUbb against a set of 40B. fragilisstrains, revealing that 75% ofB. fragilisstrains are targeted by one or the other of these two secreted proteins of strain 638R.IMPORTANCEWe are just beginning to understand some of the important interactions that occur between microbes of the human gut microbiota that dictate the composition and abundance of its constituent members. The ability of one member to produce molecules that directly kill a coresident member has been shown among minor gut species and is just starting to be studied in the abundantBacteroidesspecies. Here, we show that some strains ofBacteroides fragilishave acquired a gene encoding a secreted eukaryotic-like ubiquitin protein with potent inhibitory activity against otherB. fragilisstains. This is the first bacterially encoded ubiquitin-like molecule shown to function like a bacterial toxin. This molecule is an example of a gut symbiont acquiring and adapting a eukaryotic molecule likely to increase its competitiveness in the mammalian gut. Understanding antagonistic factors produced by abundant gut symbionts is an important prerequisite to properly engineer strains to colonize the gut for health benefits.

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