scholarly journals Synergism of imipenem with fosfomycin associated with the active cell wall recycling and heteroresistance in Acinetobacter calcoaceticus-baumannii complex

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Uthaibhorn Singkham-in ◽  
Tanittha Chatsuwan
Keyword(s):  
Cell Wall ◽  
De Novo ◽  
Acinetobacter Calcoaceticus ◽  
Active Cell ◽  
Wild Type ◽  
Cell Wall Metabolism ◽  
Carbapenem Resistant ◽  
Type Form ◽  
Wild Type Form ◽  
Cell Wall Recycling

AbstractThe carbapenem-resistant Acinetobacter calcoaceticus-baumannii (ACB) complex has become an urgent threat worldwide. Here, we determined antibiotic combinations and the feasible synergistic mechanisms against three couples of ACB (A. baumannii (AB250 and A10), A. pittii (AP1 and AP23), and A. nosocomialis (AN4 and AN12)). Imipenem with fosfomycin, the most effective in the time-killing assay, exhibited synergism to all strains except AB250. MurA, a fosfomycin target encoding the first enzyme in the de novo cell wall synthesis, was observed with the wild-type form in all isolates. Fosfomycin did not upregulate murA, indicating the MurA-independent pathway (cell wall recycling) presenting in all strains. Fosfomycin more upregulated the recycling route in synergistic strain (A10) than non-synergistic strain (AB250). Imipenem in the combination dramatically downregulated the recycling route in A10 but not in AB250, demonstrating the additional effect of imipenem on the recycling route, possibly resulting in synergism by the agitation of cell wall metabolism. Moreover, heteroresistance to imipenem was observed in only AB250. Our results indicate that unexpected activity of imipenem on the active cell wall recycling concurrently with the presence of heteroresistance subpopulation to imipenem may lead to the synergism of imipenem and fosfomycin against the ACB isolates.

scholarly journals Inactivation of the selB Gene in Methanococcus maripaludis: Effect on Synthesis of Selenoproteins and Their Sulfur-Containing Homologs

2003 ◽  
Vol 185 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Michael Rother ◽  
Isabella Mathes ◽  
Friedrich Lottspeich ◽  
August Böck
Keyword(s):  
Gene Product ◽  
Formate Dehydrogenase ◽  
Selenium Supplementation ◽  
Wild Type ◽  
Methanococcus Maripaludis ◽  
Translation Factor ◽  
Type Form ◽  
And Function ◽  
Sulfur Containing ◽  
Wild Type Form

ABSTRACT The genome of Methanococcus maripaludis harbors genes for at least six selenocysteine-containing proteins and also for homologs that contain a cysteine codon in the position of the UGA selenocysteine codon. To investigate the synthesis and function of both the Se and the S forms, a mutant with an inactivated selB gene was constructed and analyzed. The mutant was unable to synthesize any of the selenoproteins, thus proving that the gene product is the archaeal translation factor (aSelB) specialized for selenocysteine insertion. The wild-type form of M. maripaludis repressed the synthesis of the S forms of selenoproteins, i.e., the selenium-independent alternative system, in selenium-enriched medium, but the mutant did not. We concluded that free selenium is not involved in regulation but rather a successional compound such as selenocysteyl-tRNA or some selenoprotein. Apart from the S forms, several enzymes from the general methanogenic route were affected by selenium supplementation of the wild type or by the selB mutation. Although the growth of M. maripaludis on H2/CO2 is only marginally affected by the selB lesion, the gene is indispensable for growth on formate because M. maripaludis possesses only a selenocysteine-containing formate dehydrogenase.

scholarly journals Seed Production and Germination of Eight Cultivars and the Wild Type of Ruellia tweediana: A Potentially Invasive Ornamental

2003 ◽  
Vol 21 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Sandra B. Wilson ◽  
Laurie K. Mecca
Keyword(s):  
Seed Production ◽  
Invasive Plant ◽  
Temperature Treatment ◽  
Native Plant ◽  
Wild Type ◽  
Type Form ◽  
Storage Studies ◽  
Exotic Pest ◽  
Exotic Pest Plant ◽  
Wild Type Form

Abstract Seed production and the influence of light and temperature on germination were determined for eight cultivars and the wild type form of Mexican petunia (Ruellia tweediana Griseb). The wild type form of R. tweediana has been ranked by the Florida Exotic Pest Plant Council as a Category I invasive plant, meaning it has invaded and is disrupting native plant communities in Florida. The cultivar ‘Purple Showers’ did not set any seed. Peak flowering and seed production for other cultivars generally occurred in August with ‘Morado Chi’, ‘Chi Chi’, and the wild type plants producing approximately three times the amount of seed produced by ‘Katie Pink’, ‘Katie Purple’, ‘Katie White’, and ‘Snow White’. For seed germination, significant cultivar x light interactions occurred for each temperature treatment. Some germination was observed at each temperature except for ‘Katie Purple’, ‘Katie Variegated’, and ‘Katie White’ at 33C (91.4F) without light. Regardless of cultivar or provision of light, 94-100% germination occurred at 30/20C (86/68F), with the exception of ‘Katie Purple’ (65%), ‘Katie Variegated’ (54%), and ‘Katie White’ (83%) without light. At 15, 24 or 33C (59, 75.2, and 91.4F), germination was generally greatest for ‘Chi Chi’ (with or without light) and ‘Morado Chi’ (with light). In parallel greenhouse studies, where seeds were germinated in pots containing a soilless medium, highest germination was achieved by ‘Chi Chi’, ‘Katie Pink’, ‘Katie Variegated’ and ‘Morado Chi’, while significantly lower germination was achieved by wild type plants (55%) by day 14. Storage studies demonstrated that germination of seed collected from the wild type and ‘Chi Chi’ plants began to decrease between 6 and 12 months when maintained at 24C (75.2F) but had equal (‘Chi Chi’) or higher (wild type) germination when maintained at 4C (39.2F) for 12 months.

scholarly journals Biofilm-Constructing Variants of Paraburkholderia phytofirmans PsJN Outcompete the Wild-Type Form in Free-Living and Static Conditions but Not In Planta

2019 ◽  
Vol 85 (11) ◽  
Author(s):  
Marine Rondeau ◽  
Qassim Esmaeel ◽  
Jérôme Crouzet ◽  
Pauline Blin ◽  
Isabelle Gosselin ◽  
...  
Keyword(s):  
Wild Type ◽  
In Planta ◽  
Free Living ◽  
Iron Sulfur Cluster ◽  
Content Type ◽  
Iron Sulfur ◽  
Type Form ◽  
Static Conditions ◽  
Wild Type Form

ABSTRACT Members of the genus Burkholderia colonize diverse ecological niches. Among the plant-associated strains, Paraburkholderia phytofirmans PsJN is an endophyte with a broad host range. In a spatially structured environment (unshaken broth cultures), biofilm-constructing specialists of P. phytofirmans PsJN colonizing the air-liquid interface arose at high frequency. In addition to forming a robust biofilm in vitro and in planta on Arabidopsis roots, those mucoid phenotypic variants display a reduced swimming ability and modulate the expression of several microbe-associated molecular patterns (MAMPs), including exopolysaccharides (EPS), flagellin, and GroEL. Interestingly, the variants induce low PR1 and PDF1.2 expression compared to that of the parental strain, suggesting a possible evasion of plant host immunity. We further demonstrated that switching from the planktonic to the sessile form did not involve quorum-sensing genes but arose from spontaneous mutations in two genes belonging to an iron-sulfur cluster: hscA (encoding a cochaperone protein) and iscS (encoding a cysteine desulfurase). A mutational approach validated the implication of these two genes in the appearance of variants. We showed for the first time that in a heterogeneous environment, P. phytofirmans strain PsJN is able to rapidly diversify and coexpress a variant that outcompete the wild-type form in free-living and static conditions but not in planta. IMPORTANCE Paraburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from the wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilm in vitro and in planta, and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneous mutations in an iron-sulfur cluster. Overall, the data provided here allow a better understanding of the adaptive mechanisms likely developed by P. phytofirmans PsJN in a heterogeneous environment.

scholarly journals Transgenic mice overexpressing the wild-type form of the HMGA1 gene develop mixed growth hormone/prolactin cell pituitary adenomas and natural killer cell lymphomas

Oncogene ◽  
2005 ◽  
Vol 24 (21) ◽  
pp. 3427-3435 ◽  
Author(s):  
Monica Fedele ◽  
Francesca Pentimalli ◽  
Gustavo Baldassarre ◽  
Sabrina Battista ◽  
Andres JP Klein-Szanto ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Natural Killer Cell ◽  
Transgenic Mice ◽  
Natural Killer ◽  
Pituitary Adenomas ◽  
Killer Cell ◽  
Wild Type ◽  
Prolactin Cell ◽  
Type Form ◽  
Wild Type Form

Discovery of a Potent and Selective EGFR Inhibitor (AZD9291) of Both Sensitizing and T790M Resistance Mutations That Spares the Wild Type Form of the Receptor

2014 ◽  
Vol 57 (20) ◽  
pp. 8249-8267 ◽  
Author(s):  
M. Raymond V. Finlay ◽  
Mark Anderton ◽  
Susan Ashton ◽  
Peter Ballard ◽  
Paul A. Bethel ◽  
...  
Keyword(s):  
Egfr Inhibitor ◽  
Wild Type ◽  
Resistance Mutations ◽  
Type Form ◽  
Wild Type Form

scholarly journals NONHOMOLOGOUS PAIRING IN MICE HETEROZYGOUS FOR A t HAPLOTYPE CAN PRODUCE RECOMBINANT CHROMOSOMES WITH DUPLICATIONS AND DELETIONS

Genetics ◽  
1986 ◽  
Vol 113 (3) ◽  
pp. 723-734
Author(s):  
Nora Sarvetnick ◽  
Howard S Fox ◽  
Elizabeth Mann ◽  
Paul E Mains ◽  
Rosemary W Elliott ◽  
...  
Keyword(s):  
Recombination Event ◽  
Genetic Material ◽  
Chromosome 17 ◽  
Structure And Properties ◽  
Wild Type ◽  
Molecular Studies ◽  
Type Form ◽  
Wild Type Form ◽  
T Locus ◽  
T Haplotype

ABSTRACT We have investigated the structure and properties of a chromosomal product recovered from a rare recombination event between a t haplotype and a wild-type form of mouse chromosome 17. Our embryological and molecular studies indicate that this chromosome (twLub  2) is characterized by both a deletion and duplication of adjacent genetic material. The deletion appears to be responsible for a dominant lethal maternal effect and a recessive embryonic lethality. The duplication provides an explanation for the twLub  2 suppression of the dominant T locus phenotype. A reanalysis of previously described results with another chromosome 17 variant called TtOrl indicates a structure for this chromosome that is reciprocal to that observed for twLub  2. We have postulated the existence of an inversion over the proximal portion of all complete t haplotypes in order to explain the generation of the partial t haplotypes twLub  2 and TtOrl. This proximal inversion and the previously described distal inversion are sufficient to account for all of the recombination properties that are characteristic of complete t haplotypes. The structures determined for twLub  2 and TtOrl indicate that rare recombination can occur between nonequivalent genomic sequences within the inverted proximal t region when wild-type and t chromosomes are paired in a linear, nonhomologous configuration.

scholarly journals Virulent Rough Filaments of Listeria monocytogenesfrom Clinical and Food Samples Secreting Wild-Type Levels of Cell-Free p60 Protein

2000 ◽  
Vol 38 (7) ◽  
pp. 2643-2648 ◽  
Author(s):  
Neil J. Rowan ◽  
Alan A. G. Candlish ◽  
Andreas Bubert ◽  
John G. Anderson ◽  
Karl Kramer ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Hela Cells ◽  
Morphological Characteristics ◽  
Food Samples ◽  
Food Environments ◽  
Wild Type ◽  
Type Form ◽  
Rough Cell ◽  
Multiple Cells ◽  
Wild Type Form

Atypical rough cell filaments of Listeria monocytogenes(designated FR variants), isolated from clinical and food samples, form long filaments up to 96 μm in length and demonstrated wild-type levels of adherence, invasion, and cytotoxicity to human epithelial HEp-2, Caco-2, and HeLa cells. Unlike previously described avirulent rough mutants of L. monocytogenes that secrete diminished levels of the major extracellular protein p60 and that form long chains that consist of multiple cells of similar size (designated MCR variants), FR variants secreted wild-type or greater levels of p60. This study shows that virulent filamentous forms of L. monocytogenes occur in clinical and food environments and have atypical morphological characteristics compared to those of the wild-type form.

Characterization of a mutant R11H αB-crystallin associated with human inherited cataract

2010 ◽  
Vol 391 (12) ◽  
Author(s):  
Qiang Chen ◽  
Ming Yan ◽  
Feiyan Xiang ◽  
Xin Zhou ◽  
Yuanyuan Liu ◽  
...  
Keyword(s):  
Novel Mutation ◽  
Surface Hydrophobicity ◽  
Mutant Protein ◽  
Wild Type ◽  
Type Form ◽  
Αb Crystallin ◽  
Cataract Development ◽  
Wild Type Form ◽  
Hydrophobic Exposure

Abstract αB-Crystallin plays an important part in cataract development. A novel mutation (R11H) was previously detected by our group. In the present study, we set out to investigate the possible molecular mechanism by which the R11H mutation causes cataract. We found that the mutant αB-crystallin exhibits folding defects, decreased surface hydrophobicity and enhanced chaperone-like activity compared with the wild-type αB-crystallin. The mutant protein shows nearly the same molecular mass and thermal stability as the wild-type form. Transfection studies revealed that the R11H mutant was remarkably similar to the wild-type protein in its subcellular distribution, but has an abnormal ability to induce cell apoptosis. These results suggest that the changes in hydrophobic exposure and the abnormal ability to induce programmed cell death of the mutant protein are likely to be responsible for the onset of cataract.

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