scholarly journals A new sex factor ofPseudomonas aeruginosa

1973 ◽  
Vol 21 (3) ◽  
pp. 263-272 ◽  
Author(s):  
J. M. Pemberton ◽  
B. W. Holloway
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Structural Gene ◽  
Suppressor Gene ◽  
Genetic Determinant ◽  
Sex Factors ◽  
Wild Type ◽  
Leucine Biosynthesis ◽  
Different Types ◽  
A Site ◽  
Type Strains

SUMMARYOf 150 wild-type strains ofPseudomonas aeruginosaexamined, 48 formed recombinants when mated toP. aeruginosastrain PAO FP−and hence presumably possess sex factors. Three different types of sex factor were distinguished by the pattern of transfer of particular markers in different regions of the chromosome and by the ability to confer resistance to mercury in strain PAO. One new sex factor, FP39, was studied in detail, and while similar to the previously studied FP2 in terms of transfer kinetics, natural stability and resistance to curing by acridines, it differed from FP2 in promoting chromosome transfer from a site 10 min to the left of the FP2 origin and in showing apparently aberrant entry kinetics for a leucine marker situated 48 min from the FP2 origin. This was due to FP39 having a genetic determinant either for a structural gene of leucine biosynthesis or a specific suppressor gene for this locus. PAO strains carrying both FP2 and FP39 were unstable for both sex factors, suggesting a relationship between them.

scholarly journals Genetic analysis of amidase mutants ofPseudomonas aeruginosa

1974 ◽  
Vol 23 (3) ◽  
pp. 335-359 ◽  
Author(s):  
Joan L. Betz ◽  
Jane E. Brown ◽  
Patricia H. Clarke ◽  
Martin Day
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Genetic Analysis ◽  
Structural Gene ◽  
Type Strain ◽  
Wild Type Strain ◽  
Relative Order ◽  
Regulator Gene ◽  
Wild Type ◽  
Growth Phenotype

SUMMARYMutants ofPseudomonas aeruginosa, which differed in amide growth phenotype from the wild-type strain, were subjected to genetic analysis using the generalized transducing phage F116. The map order of some mutational sites was determined by 3-factor crosses in which a mutation in the linked regulator geneamiRwas used as the outside marker to determine the relative order of mutations in the amidase structural geneamiE. Acetamide-positive transductants were recovered in crosses between amidase-negative strains and strains PhB3(PAC377), V2(PAC353) and V5(PAC356) producing mutant amidases which hydrolyse phenylacetamide and valeramide but not acetamide. Some recombinants carried the mutationamiE16 determining the properties of the mutant B amidase produced by strain B6(PAC351) from which both PhB and V class mutants were derived, while other recombinants produced A amidase determined by the wild-typeamiEgene.

scholarly journals Supplementation of Intracellular XylR Leads to Coutilization of Hemicellulose Sugars

2012 ◽  
Vol 78 (7) ◽  
pp. 2221-2229 ◽  
Author(s):  
Dan Groff ◽  
Peter I. Benke ◽  
Tanveer S. Batth ◽  
Gregory Bokinsky ◽  
Christopher J. Petzold ◽  
...  
Keyword(s):  
Wild Type ◽  
Content Type ◽  
E Coli ◽  
Gene Insertion ◽  
Starting Point ◽  
Different Types ◽  
Important Challenge ◽  
Biomass Sugars ◽  
Hemicellulosic Sugars ◽  
Type Strains

ABSTRACTEscherichia colihas the potential to be a powerful biocatalyst for the conversion of lignocellulosic biomass into useful materials such as biofuels and polymers. One important challenge in usingE. colifor the transformation of biomass sugars is diauxie, or sequential utilization of different types of sugars. We demonstrate that, by increasing the intracellular levels of the transcription factor XylR, the preferential consumption of arabinose before xylose can be eliminated. In addition, XylR augmentation must be finely tuned for robust coutilization of these two hemicellulosic sugars. Using a novel technique for scarless gene insertion, an additional copy ofxylRwas inserted into thearaBADoperon. The resulting strain was superior at cometabolizing mixtures of arabinose and xylose and was able to produce at least 36% more ethanol than wild-type strains. This strain is a useful starting point for the development of anE. colibiocatalyst that can simultaneously convert all biomass sugars.

Structure of a highly phosphorylated lipopolysaccharide core in the ΔalgC mutants derived from Pseudomonas aeruginosa wild-type strains PAO1 (serogroup O5) and PAC1R (serogroup O3)

2003 ◽  
Vol 338 (23) ◽  
pp. 2667-2677 ◽  
Author(s):  
Oliver Kooistra ◽  
Gilles Bedoux ◽  
Lothar Brecker ◽  
Buko Lindner ◽  
Patricia Sánchez Carballo ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Wild Type ◽  
Type Strains

scholarly journals Quantitative correlation between susceptibility and OprJ production in NfxB mutants of Pseudomonas aeruginosa.

1996 ◽  
Vol 40 (4) ◽  
pp. 909-913 ◽  
Author(s):  
N Masuda ◽  
N Gotoh ◽  
S Ohya ◽  
T Nishino
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Parent Strain ◽  
Type A ◽  
Immunoblot Analysis ◽  
Type B ◽  
Wild Type ◽  
Strain Pao1 ◽  
Pseudomonas Aeruginosa Pao1 ◽  
Quantitative Correlation ◽  
Different Types

Various Pseudomonas aeruginosa PAO1 NfxB mutants were isolated on agar plates containing cefpirome and ofloxacin. They were classified into type A and type B, based on the degrees of changes in their susceptibilities. Type A mutants were four to eight times more resistant to ofloxacin, erythromycin, and new zwitterionic cephems, i.e., cefpirome, cefclidin, cefozopran, and cefoselis, than was the parent strain, PAO1. In contrast, type B mutants were more resistant to tetracycline and chloramphenicol, as well as ofloxacin, erythromycin, and the new zwitterionic cephems, than was PAO1, and they were four to eight times more susceptible to carbenicillin, sulbenicillin, imipenem, panipenem, biapenem, moxalactam, aztreonam, gentamicin, and kanamycin that was PAO1. The changes in susceptibilities of type B mutants were greater than those of type A mutants. The susceptibilities of both type A and type B mutants were restored to the level of PAO1 by transformation with plasmid pNF111, which contained the wild-type nfxB gene, demonstrating that they are NfxB mutants. Immunoblot analysis with a monoclonal antibody to OprJ revealed that type B mutants produced larger amounts of outer membrane protein OprJ than did type A mutants and that PAO1 produced an undetectable amount of it. Moreover, transconjugants obtained with the different types of NfxB mutants as the donor strains showed almost the same phenotypes as the corresponding donor strains. These results suggest that there are at least two nfxB mutations that show different phenotypes and that production of OprJ is associated with changes in susceptibilities of NfxB mutants.

scholarly journals Altered Pseudomonas Strategies to Inhibit Surface Aspergillus Colonies

2021 ◽  
Vol 11 ◽  
Author(s):  
Gabriele Sass ◽  
Hasan Nazik ◽  
Paulami Chatterjee ◽  
Pallabi Shrestha ◽  
Marie-Christine Groleau ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antifungal Activity ◽  
Quorum Sensing ◽  
Ferric Iron ◽  
Immunocompromised Patients ◽  
Wild Type ◽  
Liquid Cultures ◽  
Antifungal Effects ◽  
Type Strains

Pseudomonas aeruginosa and Aspergillus fumigatus infections frequently co-localize in lungs of immunocompromised patients and individuals with cystic fibrosis (CF). The antifungal activity of P. aeruginosa has been described for its filtrates. Pyoverdine and pyocyanin are the principal antifungal P. aeruginosa molecules active against A. fumigatus biofilm metabolism present in iron-limited or iron-replete planktonic P. aeruginosa culture filtrates, respectively. Using various P. aeruginosa laboratory wild-type strains (PA14, PAO1, PAK), we found antifungal activity against Aspergillus colonies on agar. Comparing 36 PA14 and 7 PAO1 mutants, we found that mutants lacking both major siderophores, pyoverdine and pyochelin, display higher antifungal activity on agar than their wild types, while quorum sensing mutants lost antifungal activity. Addition of ferric iron, but not calcium or magnesium, reduced the antifungal effects of P. aeruginosa on agar, whereas iron-poor agar enhanced antifungal effects. Antifungal activity on agar was mediated by PQS and HHQ, via MvfR. Among the MvfR downstream factors, rhamnolipids and elastase were produced in larger quantities by pyoverdine–pyochelin double mutants and showed antifungal activity on agar. In summary, antifungal factors produced by P. aeruginosa on agar differ from those produced by bacteria grown in liquid cultures, are dependent on quorum sensing, and are downregulated by the availability of ferric iron. Rhamnolipids and elastase seem to be major mediators of Pseudomonas’ antifungal activity on a solid surface.

scholarly journals Ribosomal DNA is a site of chromosome breakage in aneuploid strains of Neurospora.

Genetics ◽  
1992 ◽  
Vol 131 (3) ◽  
pp. 581-592 ◽  
Author(s):  
D K Butler
Keyword(s):  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Chromosome Breakage ◽  
Terminal Segment ◽  
Nucleolus Organizer ◽  
Wild Type ◽  
Repeat Units ◽  
The Right ◽  
A Site ◽  
Type Strains

Abstract In wild-type strains of Neurospora crassa, the rDNA is located at a single site in the genome called the nucleolus organizer region (NOR), which forms a terminal segment on linkage group (LG) V. In the quasiterminal translocation strain T(I;V)AR190, most of the right arm of LG I moved to the distal tip of the NOR, and one or a few rDNA repeat units are moved to the truncated right arm of LG I. I report here that, in partial diploid strains derived from T(I;V)AR190, large terminal deletions result from chromosome breakage in the NOR. In most of these partial diploids, chromosome breakage is apparently frequent and the breakpoints occur in many parts of the NOR. The rDNA ends resulting from chromosome breakage are "healed" by the addition of new telomeres. Significantly, the presence of ectopic rDNA creates a new site of chromosome breakage in the genome of partial diploids. These results raise the possibility that, under certain conditions, rDNA is a region of fragility in eukaryotic chromosomes.

scholarly journals Functional expression of a yeast mitochondrial intron-encoded protein requires RNA processing at a conserved dodecamer sequence at the 3' end of the gene.

1989 ◽  
Vol 9 (4) ◽  
pp. 1507-1512 ◽  
Author(s):  
H Zhu ◽  
H Conrad-Webb ◽  
X S Liao ◽  
P S Perlman ◽  
R A Butow
Keyword(s):  
Genetic Analysis ◽  
Rna Processing ◽  
Fold Increase ◽  
Functional Expression ◽  
Rrna Gene ◽  
Yeast Mitochondria ◽  
Wild Type ◽  
Site Specific ◽  
Var1 Gene ◽  
A Site

All mRNAs of yeast mitochondria are processed at their 3' ends within a conserved dodecamer sequence, 5'-AAUAAUAUUCUU-3'. A dominant nuclear suppressor, SUV3-I, was previously isolated because it suppresses a dodecamer deletion at the 3' end of the var1 gene. We have tested the effects of SUV3-1 on a mutant containing two adjacent transversions within a dodecamer at the 3' end of fit1, a gene located within the 1,143-base-pair intron of the 21S rRNA gene, whose product is a site-specific endonuclease required in crosses for the quantitative transmission of that intron to 21S alleles that lack it. The fit1 dodecamer mutations blocked both intron transmission and dodecamer cleavage, neither of which was suppressed by SUV3-1 when present in heterozygous or homozygous configurations. Unexpectedly, we found that SUV3-1 completely blocked cleavage of the wild-type fit1 dodecamer and, in SUV3-1 homozygous crosses, intron conversion. In addition, SUV3-1 resulted in at least a 40-fold increase in the amount of excised intron accumulated. Genetic analysis showed that these phenotypes resulted from the same mutation. We conclude that cleavage of a wild-type dodecamer sequence at the 3' end of the fit1 gene is essential for fit1 expression.

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