Antigenic variation and increase in pathogenicity in Pseudomonas aeruginosa as a result of growth on glucose or N-hexadecane as sole carbon source

1978 ◽  
Vol 24 (6) ◽  
pp. 675-679 ◽  
Author(s):  
Robert S. Stinson ◽  
D. E. Talburt

When Pseudomonas aeruginosa is grown on glucose as opposed to n-hexadecane as the sole carbon source, the antigenicity, virulence, and protein composition of the outer membrane are altered. The hydrocarbon-grown cells demonstrate a 3-log increase in virulence over the glucose-grown cells (in mice). There also appears to be an additional protein present in the outer membrane of the n-hexadecane-grown cells. This protein may contribute to the observed antigenic differences between the two cell types.

2020 ◽  
Vol 367 (10) ◽  
Author(s):  
Rodolfo García-Contreras ◽  
Daniel Loarca ◽  
Caleb Pérez-González ◽  
J Guillermo Jiménez-Cortés ◽  
Abigail Gonzalez-Valdez ◽  
...  

ABSTRACT Pseudomonas aeruginosa is one of the main models to study social behaviors in bacteria since it synthesizes several exoproducts, including exoproteases and siderophores and release them to the environment. Exoproteases and siderophores are public goods that can be utilized by the individuals that produce them but also by non-producers, that are considered social cheaters. Molecularly exoprotease cheaters are mutants in regulatory genes such as lasR, and are commonly isolated from chronic infections and selected in the laboratory upon serial cultivation in media with protein as a sole carbon source. Despite that the production of exoproteases is exploitable, cooperators have also ways to restrict the growth and selection of social cheaters, for instance by producing toxic metabolites like pyocyanin. In this work, using bacterial competitions, serial cultivation and growth assays, we demonstrated that rhamnolipids which production is regulated by quorum sensing, selectively affect the growth of lasR mutants and are able to restrict social cheating, hence contributing to the maintenance of cooperation in Pseudomonas aeruginosa populations.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Walaa A. Eraqi ◽  
Aymen S. Yassin ◽  
Amal E. Ali ◽  
Magdy A. Amin

Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We have developed a process for the production of rhamnolipid biosurfactants using glycerol as the sole carbon source by a local Pseudomonas aeruginosa isolate that was obtained from an extensive screening program. A factorial design was applied with the goal of optimizing the rhamnolipid production. The highest production yield was obtained after 2 days when cells were grown in minimal salt media at pH 6, containing 1% (v/v) glycerol and 2% (w/v) sodium nitrate as nitrogen source, at 37°C and at 180 rpm, and reached 2.164 g/L after 54 hours (0.04 g/L h). Analysis of the produced rhamnolipids by TLC, HPLC, and FTIR confirmed the nature of the biosurfactant as monorhamnolipid. Glycerol can serve as a source for the production of rhamnolipid from microbial isolates providing a cheap and reliable substrate.


2003 ◽  
Vol 9 (1) ◽  
pp. 27-31
Author(s):  
I Made Sudiana

Detergent contained of Linear Alkyl Sulfonate (LAS) is toxic material to human, animal and microorganism. Strain S1 isolated from detergent contaminated soil was able to grow in media with LAS as a sole carbon source. LAS degradation took place under aerobic condition, with μmax of 0.31-h, Ks = 7.75 mg/L, Vmax = 1.04 mg/L.hour-1and Km = 8.119 mg/L. Analyses of 16s rDNA revealed that S1 is belonging to Pseudomonas aeruginosa.


1976 ◽  
Vol 4 (5) ◽  
pp. 443-449
Author(s):  
G W Ajello ◽  
A W Hoadley

One hundred and twenty-seven apyocyanogenic fluorescent Pseudomonas strains capable of growth at 41 degrees C, but differing from Pseudomonas aeruginosa, were typed serologically and tested for pyocin production, antibiotic susceptibility, selected biochemical reactions, and utilization of selected substrates. Results were compared with those from 40 apyocyanogenic and 14 pyocyanin-producing strains of P. aeruginosa. Unidentified fluorescent Pseudomonas (UFP) strains generally were not agglutinated by P. aeruginosa antisera and showed little or no pyocin activity. In contrast to P. aeruginosa strains, UFP strains usually failed to oxidize D-gluconate or reduce nitrate to nitrogen gas. They could not use D-gluconate or D-mannitol as sole carbon source and were susceptible to kanamycin. The cellular fatty acid compositions of major UFP groups resembled those of the alcaligenes-stutzeri groups.


1986 ◽  
Vol 32 (3) ◽  
pp. 248-253 ◽  
Author(s):  
Carlos B. Miguez ◽  
Terry J. Beveridge ◽  
Jordan M. Ingram

Pseudomonas aeruginosa ATCC 9027 grew on 0.5% (v/v) hexadecane as a sole carbon source in a chemically defined medium which required the addition of Fe3+ and Ca2+. There was a variable and extended lag period before an active growth rate was attained. Visible light microscopic evidence revealed that the bacteria did not adhere to hexadecane droplets suggesting the absence of a bioemulsifier. When compared with glucose-grown cells, hexadecane-grown cells produced 75% less lipopolysaccharide (on a total protein basis); this lipopolysaccharide contained 30–40% less carbohydrate, yet 50–75% more 2-keto-3-deoxyoctonate. These chemical changes made the cell surface appear more hydrophobic when tested in a biphasic hydrophobicity index system. Electron microscopy of thin sections and freeze etchings revealed hexadecane-grown cells contained granules which were judged to be polyphosphate by energy dispersive X-ray analysis. There was no apparent major morphological envelope alteration within the two cell types.


2014 ◽  
Vol 1073-1076 ◽  
pp. 666-671
Author(s):  
Guang Chun Li ◽  
Chun Xiang Piao ◽  
Katsuhiko Saido ◽  
Seon Yong Chung

Biodegradation of the styrene trimer was investigated, and its degrading bacteria were screened and isolated. Complex bacteria ST (strain ST1 and ST2) was isolated from contaminated soil by polystyrene and named by strain ST1 and ST2. ST1 and ST2 were identified by 16S rDNA and classified byOchrobactrum intermediumsp. andPseudomonas aeruginosasp., respectively. Biodegradation experiments were performed in batch and styrene trimer was used as a sole carbon source. Isolated two bacteria were used as degrading microorganisms. Initial liquid phase concentration of the styrene trimer was 50 mg/L. 95% of the styrene trimer was degraded in 17 days by the complex strain ST. The concentration was analyzed by using GC. Metabolites of bacteria were analyzed and three kinds of products that were identified by GC/MS.


Author(s):  
Vincent Chigor ◽  
Chidiebele Nwankwo ◽  
Uchenna Ogbodo ◽  
Joseph Ugwu

Background: Low Density Polyethylene (LDPE) are plastic materials extensively used in packaging, constituting recalcitrant environmental pollutants that defy natural degradation processes. Aim: This study isolated bacteria from a Nigerian environment and assessed their potential for LDPE biodegradation. Methods: Using standard procedures, Bacteria were isolated from polythene samples collected from farmlands and waste dump sites in Nsukka metropolis. Mineral salt medium (MSM) was prepared, with LPDE as sole carbon source, and used for isolation. Optical density (OD600 nm) was used to study bacterial growth on LDPE as sole carbon source as proof of biodegradation. Both organisms demonstrated steady growth on LDPE over time. Results: Pseudomonas aeruginosa and Micrococcus sp. were identified based on morphological and biochemical characteristics. Ability to grow on LDPE as a sole carbon source was studied as evidence of polyethylene biodegradation. Organisms were inoculated into MSM and incubated at 37°C and 50°C for 15 days. Maximum growth was recorded after 15 days of incubation for both organisms. P. aeruginosa and Micrococcus sp. showed steady growth at 37°C as well as 50 ⁰C. Micrococcus sp. recorded highest growth; 0.324 nm and 0.312 nm at 37°C and 50°C respectively, after 15 days. Similarly, P. aeruginosa recorded highest growth of 0.40 nm and 0.258 nm for 37°C and 50°C respectively. LDPE degradation increased with increase in time. Conclusion: This study demonstrates the enormous polyethylene-degrading potentials of P. aeruginosa and Micrococcus sp. isolated from Nsukka, Nigeria.


1969 ◽  
Vol 15 (6) ◽  
pp. 595-598 ◽  
Author(s):  
W. M. Ingledew ◽  
J. J. R. Campbell

A medium for the production of the phenazine pigment pyocyanine by Pseudomonas aeruginosa has been developed. The medium was deficient in phosphate and contained ammonium chloride, inorganic salts, and 2-ketogluconate as sole carbon source. Rapid initiation of pigment formation was observed with synthesis being completed at 24 h. Kinetics of growth, substrate concentration, pigment elaboration, and phosphate liberation have been examined. In the presence of excess nitrogen pigment concentration was proportional to the level of 2-ketogluconate used.


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