scholarly journals Functions of VPA1418 and VPA0305 Catalase Genes in Growth of Vibrio parahaemolyticus under Oxidative Stress

2016 ◽  
Vol 82 (6) ◽  
pp. 1859-1867 ◽  
Author(s):  
Ching-Lian Chen ◽  
Shin-yuan Fen ◽  
Chun-Hui Chung ◽  
Shu-Chuan Yu ◽  
Cheng-Lun Chien ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Culture Medium ◽  
Incubation Temperature ◽  
Content Type ◽  
Inhibition Of Growth ◽  
Homologous Genes ◽  
Mutant Strains ◽  
In The Wild ◽  
Incubation Temperatures ◽  
Logarithmic Growth

ABSTRACTThe marine foodborne enteropathogenVibrio parahaemolyticushas four putative catalase genes. The functions of twokatE-homologous genes,katE1(VPA1418) andkatE2(VPA0305), in the growth of this bacterium were examined using gene deletion mutants with or without complementary genes. The growth of the mutant strains in static or shaken cultures in a rich medium at 37°C or at low temperatures (12 and 4°C), with or without competition fromEscherichia coli, did not differ from that of the parent strain. When 175 μM extrinsic H2O2was added to the culture medium, bacterial growth of the ΔkatE1strain was delayed and growth of the ΔkatE1ΔkatE2and ΔkatE1ΔahpC1double mutant strains was completely inhibited at 37°C for 8 h. The sensitivity of the ΔkatE1strain to the inhibition of growth by H2O2was higher at low incubation temperatures (12 and 22°C) than at 37°C. The determined gene expression of these catalase andahpCgenes revealed thatkatE1was highly expressed in the wild-type strain at 22°C under H2O2stress, while thekatE2andahpCgenes may play an alternate or compensatory role in the ΔkatE1strain. This study demonstrated thatkatE1encodes the chief functional catalase for detoxifying extrinsic H2O2during logarithmic growth and that the function of these genes was influenced by incubation temperature.

scholarly journals Influence ofoxyRon Growth, Biofilm Formation, and Mobility of Vibrio parahaemolyticus

2015 ◽  
Vol 82 (3) ◽  
pp. 788-796 ◽  
Author(s):  
Chun-Hui Chung ◽  
Shin-yuan Fen ◽  
Shu-Chuan Yu ◽  
Hin-chung Wong
Keyword(s):  
Biofilm Formation ◽  
Vibrio Parahaemolyticus ◽  
Deletion Mutant ◽  
Cumene Hydroperoxide ◽  
Content Type ◽  
Antioxidative Function ◽  
Cell Mobility ◽  
Inhibition Of Growth ◽  
Dipotassium Hydrogen Phosphate ◽  
In The Wild

ABSTRACTVibrio parahaemolyticusis a common marine food-borne enteropathogen. In this study, we examined the antioxidative activity, growth, biofilm formation, and cell mobility of anoxyRdeletion mutant and its genetically complementary strain ofV. parahaemolyticus.oxyRis the regulator of catalase andahpCgenes. Protection against extrinsic H2O2and against the organic peroxides cumene hydroperoxide andtert-butyl hydroperoxide was weaker in the deletion mutant than in its parent strain. Expression of the major functional antioxidative genes,ahpC1and VPA1418, was markedly decreased in theoxyRmutant. Growth of this mutant on agar medium was significantly inhibited by autoclaved 0.25% glucose and by 0.25% dipotassium hydrogen phosphate, 0.5% monosaccharides (glucose, galactose, xylose, and arabinose), or 114.8 mM phosphates. The inhibition of the growth of thisoxyRmutant by extrinsic peroxides, autoclaved sugars, and phosphates was eliminated by the complementaryoxyRgene or by the addition of catalase to the autoclaved medium, while no inhibition of growth was observed when filter-sterilized sugars were used. The formation of biofilm and swimming mobility were significantly inhibited in theoxyRmutant relative to that in the wild-type strain. This investigation demonstrates the antioxidative function ofoxyRinV. parahaemolyticusand its possible roles in biofilm formation, cell mobility, and the protection of growth in heated rich medium.

scholarly journals Incubation under climate warming affects learning ability and survival in hatchling lizards

2017 ◽  
Vol 13 (3) ◽  
pp. 20170002 ◽  
Author(s):  
Buddhi Dayananda ◽  
Jonathan K. Webb
Keyword(s):  
Spatial Learning ◽  
Climate Warming ◽  
Cognitive Abilities ◽  
Incubation Temperature ◽  
Learning Ability ◽  
Lizard Species ◽  
Southeastern Australia ◽  
Temperature Regimes ◽  
In The Wild ◽  
Incubation Temperatures

Despite compelling evidence for substantial individual differences in cognitive performance, it is unclear whether cognitive ability influences fitness of wild animals. In many animals, environmental stressors experienced in utero can produce substantial variation in the cognitive abilities of offspring. In reptiles, incubation temperatures experienced by embryos can influence hatchling brain function and learning ability. Under climate warming, the eggs of some lizard species may experience higher temperatures, which could affect the cognitive abilities of hatchlings. Whether such changes in cognitive abilities influence the survival of hatchlings is unknown. To determine whether incubation-induced changes in spatial learning ability affect hatchling survival, we incubated velvet gecko, Amalosia lesueurii , eggs using two fluctuating temperature regimes to mimic current (cold) versus future (hot) nest temperatures. We measured the spatial learning ability of hatchlings from each treatment, and released individually marked animals at two field sites in southeastern Australia. Hatchlings from hot-incubated eggs were slower learners than hatchlings from cold-incubated eggs. Survival analyses revealed that hatchlings with higher learning scores had higher survival than hatchlings with poor learning scores. Our results show that incubation temperature affects spatial learning ability in hatchling lizards, and that such changes can influence the survival of hatchlings in the wild.

scholarly journals Effect of Incubation Temperature on the Detection of Thermophilic Campylobacter Species from Freshwater Beaches, Nearby Wastewater Effluents, and Bird Fecal Droppings

2013 ◽  
Vol 79 (24) ◽  
pp. 7639-7645 ◽  
Author(s):  
Izhar U. H. Khan ◽  
Stephen Hill ◽  
Eva Nowak ◽  
Thomas A. Edge
Keyword(s):  
Surface Water ◽  
Large Scale ◽  
Incubation Temperature ◽  
Its Region ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
C 32 ◽  
Species Specific ◽  
Incubation Temperatures

ABSTRACTThis large-scale study compared incubation temperatures (37°C versus 42°C) to study the detection of thermophilicCampylobacterspecies, includingCampylobacter jejuni,C. coli, andC. lari, in various surface water samples and bird fecal droppings around Hamilton Harbor, Lake Ontario. The putative culture isolates obtained from incubation temperatures of 37 and 42°C were confirmed byCampylobactergenus- and species-specific triplex PCR assays targeting the 16S rRNA gene and the 16S-23S rRNA gene internal transcribed spacer (ITS) region. A total of 759 water, wastewater, and bird fecal dropping samples were tested. Positive amplification reactions for the genusCampylobacterwere found for 454 (60%) samples incubated at 37°C, compared to 258 (34%) samples incubated at 42°C.C. jejuni(16%) andC. lari(12%) were detected significantly more frequently at the 42°C incubation temperature than at 37°C (8% and 5%, respectively). In contrast, significantly higher rates ofC. coli(14%) and otherCampylobacterspp. (36%) were detected at the 37°C incubation temperature than at 42°C (8% and 7%, respectively). These results were consistent across surface water, wastewater, and bird fecal dropping samples. At times,Campylobacterspp. were recovered and detected at 37°C (3% forC. jejuni, 10% forC. coli, and 3% forC. lari) when the same samples incubated at 42°C were negative. A significantly higher rate of otherCampylobacterspp. was detected only at 37°C (32%) than only at 42°C (3%). These results indicate that incubation temperature can significantly influence the culturability and detection of thermophilic and other fastidiousCampylobacterspp. and that a comprehensive characterization of theCampylobacterspp. in surface water, wastewaters, or bird fecal droppings will require incubation at both 37 and 42°C.

scholarly journals Involvement of Stress-Related GenespolBandPA14_46880in Biofilm Formation of Pseudomonas aeruginosa

2014 ◽  
Vol 82 (11) ◽  
pp. 4746-4757 ◽  
Author(s):  
Sahar A. Alshalchi ◽  
Gregory G. Anderson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Acute Infection ◽  
Regulatory Gene ◽  
Chronic Infections ◽  
Content Type ◽  
Abiotic Surfaces ◽  
Mutant Strains ◽  
In The Wild ◽  
Airway Cells

ABSTRACTChronic infections ofPseudomonas aeruginosaare generally established through production of biofilm. During biofilm formation, production of an extracellular matrix and establishment of a distinct bacterial phenotype make these infections difficult to eradicate. However, biofilm studies have been hampered by the fact that most assays utilize nonliving surfaces as biofilm attachment substrates. In an attempt to better understand the mechanisms behindP. aeruginosabiofilm formation, we performed a genetic screen to identify novel factors involved in biofilm formation on biotic and abiotic surfaces. We found that deletion of genespolBandPA14_46880reduced biofilm formation significantly compared to that in the wild-type strain PA14 in an abiotic biofilm system. In a biotic biofilm model, wherein biofilms form on cultured airway cells, the ΔpolBand ΔPA14_46880strains showed increased cytotoxic killing of the airway cells independent of the total number of bacteria bound. Notably, deletion mutant strains were more resistant to ciprofloxacin treatment. This phenotype was linked to decreased expression ofalgR, an alginate transcriptional regulatory gene, under ciprofloxacin pressure. Moreover, we found that pyocyanin production was increased in planktonic cells of mutant strains. These results indicate that inactivation ofpolBandPA14_46880may inhibit transition ofP. aeruginosafrom a more acute infection lifestyle to the biofilm phenotype. Future investigation of these genes may lead to a better understanding ofP. aeruginosabiofilm formation and chronic biofilm infections.

scholarly journals Biosynthesis and Functions of a Melanoid Pigment Produced by Species of the Sporothrix Complex in the Presence of l-Tyrosine

2012 ◽  
Vol 78 (24) ◽  
pp. 8623-8630 ◽  
Author(s):  
Rodrigo Almeida-Paes ◽  
Susana Frases ◽  
Glauber de Sousa Araújo ◽  
Manoel Marques Evangelista de Oliveira ◽  
Gary J. Gerfen ◽  
...  
Keyword(s):  
Culture Medium ◽  
Uv Light ◽  
Sporothrix Schenckii ◽  
Pigment Production ◽  
Yeast Cells ◽  
Fungal Cell ◽  
Content Type ◽  
Mutant Strains ◽  
Important Virulence Factor ◽  
Medical Interest

ABSTRACTSporothrix schenckiiis the etiological agent of sporotrichosis, the main subcutaneous mycosis in Latin America. Melanin is an important virulence factor ofS. schenckii, which produces dihydroxynaphthalene melanin (DHN-melanin) in conidia and yeast cells. Additionally,l-dihydroxyphenylalanine (l-DOPA) can be used to enhance melanin production on these structures as well as on hyphae. Some fungi are able to synthesize another type of melanoid pigment, called pyomelanin, as a result of tyrosine catabolism. Since there is no information about tyrosine catabolism inSporothrixspp., we cultured 73 strains, including representatives of newly describedSporothrixspecies of medical interest, such asS. brasiliensis,S. schenckii, andS. globosa, in minimal medium with tyrosine. All strains but one were able to produce a melanoid pigment with a negative charge in this culture medium after 9 days of incubation. AnS. schenckiiDHN-melanin mutant strain also produced pigment in the presence of tyrosine. Further analysis showed that pigment production occurs in both the filamentous and yeast phases, and pigment accumulates in supernatants during stationary-phase growth. Notably, sulcotrione inhibits pigment production. Melanin ghosts of wild-type and DHN mutant strains obtained when the fungus was cultured with tyrosine were similar to melanin ghosts yielded in the absence of the precursor, indicating that this melanin does not polymerize on the fungal cell wall. However, pyomelanin-producing fungal cells were more resistant to nitrogen-derived oxidants and to UV light. In conclusion, at least three species of theSporothrixcomplex are able to produce pyomelanin in the presence of tyrosine, and this pigment might be involved in virulence.

scholarly journals Isolation and mycelial growth of Diehliomyces microsporus: effect of culture medium and incubation temperature

2007 ◽  
Vol 50 (4) ◽  
pp. 587-595 ◽  
Author(s):  
José Soares do Nascimento ◽  
Augusto Ferreira da Eira
Keyword(s):  
Fruiting Body ◽  
Mycelial Growth ◽  
Culture Medium ◽  
Incubation Temperature ◽  
Culture Media ◽  
Growth Speed ◽  
Three Stages ◽  
False Truffle ◽  
Incubation Temperatures

The false truffle is one of the main problems in the production of the Agaricus brasiliensis in Brazil and the control of this fungal competitor has been rather difficult due to difficulties in the isolation and cultivation of this pathogen. This experiment was conducted in three stages, the first consisting of the isolation of Diehliomyces microsporus starting from portions of the fruiting body and through the ascospores suspension; second, D. microsporus cultivated in vitro at 15, 20, 25, 30 and 35ºC in six different culture media (CSDA, OCDA, PCDA, ODA, PDA, CDA); third, D. microsporus was inoculated on sterilized compost for formation of the fruiting body. The colony formation from tissue of D. microsporus starting from portions of fruiting body was more efficient than germination of the ascospores. Compost medium (CDA) allowed a larger diameter of the D. microsporus colony, followed by the medium made up of compost and potato mixture, favoring a denser composition. The largest mycelial growth speed of D. microsporus occurred when the culture was incubated at 28 and 30ºC. Incubation temperatures lower than 15ºC or above 35ºC inhibited the mycelial growth of D. microsporus completely. The fruiting bodies were obtained easily in sterilized compost and later inoculated along with mycelial competitor.

scholarly journals Deciphering the Role of Multiple Betaine-Carnitine-Choline Transporters in the Halophile Vibrio parahaemolyticus

2014 ◽  
Vol 81 (1) ◽  
pp. 351-363 ◽  
Author(s):  
Serge Y. Ongagna-Yhombi ◽  
Nathan D. McDonald ◽  
E. Fidelma Boyd
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Growth Analysis ◽  
Nacl Stress ◽  
Transport Systems ◽  
Content Type ◽  
Mutant Strains ◽  
Single Deletion ◽  
Quadruple Mutant ◽  
Response Expression

ABSTRACTVibrio parahaemolyticusis a halophile that is the predominant cause of bacterial seafood-related gastroenteritis worldwide. To survive in the marine environment,V. parahaemolyticusmust have adaptive strategies to cope with salinity changes. Six putative compatible solute (CS) transport systems were previously predicted from the genome sequence ofV. parahaemolyticusRIMD2210633. In this study, we determined the role of the four putative betaine-carnitine-choline transporter (BCCT) homologues VP1456, VP1723, VP1905, and VPA0356 in the NaCl stress response. Expression analysis of the four BCCTs subjected to NaCl upshock showed that VP1456, VP1905, and VPA0356, but not VP1723, were induced. We constructed in-frame single-deletion mutant strains for all four BCCTs, all of which behaved similarly to the wild-type strain, demonstrating a redundancy of the systems. Growth analysis of a quadruple mutant and four BCCT triple mutants demonstrated the requirement for at least one BCCT for efficient CS uptake. We complementedEscherichia coliMHK13, a CS synthesis- and transporter-negative strain, with each BCCT and examined CS uptake by growth analysis and1H nuclear magnetic resonance (NMR) spectroscopy analyses. These data demonstrated that VP1456 had the most diverse substrate transport ability, taking up glycine betaine (GB), proline, choline, and ectoine. VP1456 was the sole ectoine transporter. In addition, the data demonstrated that VP1723 can transport GB, proline, and choline, whereas VP1905 and VPA0356 transported only GB. Overall, the data showed that the BCCTs are functional and that there is redundancy among them.

scholarly journals Activities of Alkyl Hydroperoxide Reductase Subunits C1 and C2 of Vibrio parahaemolyticus against Different Peroxides

2014 ◽  
Vol 80 (23) ◽  
pp. 7398-7404 ◽  
Author(s):  
Chun-Hui Chung ◽  
Tsung-yong Ma ◽  
Shin-yuan Fen ◽  
Hin-chung Wong
Keyword(s):  
Liquid Medium ◽  
Vibrio Parahaemolyticus ◽  
Vibrio Vulnificus ◽  
Incubation Temperature ◽  
Cumene Hydroperoxide ◽  
Organic Peroxides ◽  
Homologous Proteins ◽  
Alkyl Hydroperoxide Reductase ◽  
Content Type ◽  
Alkyl Hydroperoxide

ABSTRACTAlkyl hydroperoxide reductase subunit C gene (ahpC) functions were characterized inVibrio parahaemolyticus, a commonly occurring marine food-borne enteropathogenic bacterium. TwoahpCgenes,ahpC1(VPA1683) andahpC2(VP0580), encoded putative two-cysteine peroxiredoxins, which are highly similar to the homologous proteins ofVibrio vulnificus. The responses of deletion mutants ofahpCgenes to various peroxides were compared with and without gene complementation and at different incubation temperatures. The growth of theahpC1mutant andahpC1 ahpC2double mutant in liquid medium was significantly inhibited by organic peroxides, cumene hydroperoxide andtert-butyl hydroperoxide. However, inhibition was higher at 12°C and 22°C than at 37°C. Inhibiting effects were prevented by the complementaryahpC1gene. Inconsistent detoxification of H2O2byahpCgenes was demonstrated in an agar medium but not in a liquid medium. Complementation with anahpC2gene partially restored the peroxidase effect in the doubleahpC1 ahpC2mutant at 22°C. This investigation reveals thatahpC1is the chief peroxidase gene that acts against organic peroxides inV. parahaemolyticusand that the function of theahpCgenes is influenced by incubation temperature.

scholarly journals Association of a d-Alanyl-d-Alanine Carboxypeptidase Gene with the Formation of Aberrantly Shaped Cells during the Induction of Viable but Nonculturable Vibrio parahaemolyticus

2013 ◽  
Vol 79 (23) ◽  
pp. 7305-7312 ◽  
Author(s):  
Wei-cheng Hung ◽  
Wann-Neng Jane ◽  
Hin-chung Wong
Keyword(s):  
Cell Wall ◽  
Vibrio Parahaemolyticus ◽  
Culture Medium ◽  
Culture Media ◽  
Cell Wall Synthesis ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
Content Type ◽  
Initial Stage ◽  
Enhanced Expression

ABSTRACTVibrio parahaemolyticusis a halophilic Gram-negative bacterium that causes human gastroenteritis. When the viable but nonculturable (VBNC) state of this bacterium was induced by incubation at 4°C in Morita minimal salt solution containing 0.5% NaCl, the rod-shaped cells became coccoid, and various aberrantly shaped intermediates were formed in the initial stage. This study examined the factors that influence the formation of these aberrantly shaped cells. The proportion of aberrantly shaped cells was not affected in a medium containingd-cycloserine (50 μg/ml) but was lower in a medium containing cephalosporin C (10 μg/ml) than in the control medium without antibiotics. The proportion of aberrantly shaped cells was higher in a culture medium that contained 0.5% NaCl than in culture media containing 1.0 or 1.5% NaCl. The expression of 15 of 17 selected genes associated with cell wall synthesis was enhanced, and the expression of VP2468 (dacB), which encodesd-alanyl-d-alanine carboxypeptidase, was enhanced the most. The proportion of aberrantly shaped cells was significantly lower in thedacBmutant strain than in the parent strain, but the proportion was restored in the presence of the complementarydacBgene. This study suggests that disturbance of the dynamics of cell wall synthesis by enhanced expression of the VP2468 gene is associated with the formation of aberrantly shaped cells in the initial stage of induction of VBNCV. parahaemolyticuscells under specific conditions.

Ligilactobacillus agilis BKN88 possesses thermo-/acid-stable heteropolymeric flagellar filaments

Microbiology ◽  
2021 ◽  
Author(s):  
Naoto Eguchi ◽  
Shunya Suzuki ◽  
Kenji Yokota ◽  
Shizunobu Igimi ◽  
Akinobu Kajikawa
Keyword(s):  
Type Species ◽  
Wild Type ◽  
Flagellin Gene ◽  
Specific Staining ◽  
Content Type ◽  
Link Type ◽  
Mutant Strains ◽  
In The Wild ◽  
Toll Like Receptor 5 ◽  
Acid Stable

Many flagellated bacteria possess multiple flagellins, but the roles and the compositions of each flagellin are diverse and poorly understood. In Ligilactobacillus agilis BKN88, there are two active flagellin gene paralogues but their function and composition in its flagellar filaments have not been described. The aim of this study is to find the function and composition of the flagellins by employing mutant strains each of which expresses a single flagellin or a modified flagellin. Two single flagellin-expressing strains were both flagellated while the number of flagella per cell in the single flagellin-expressing derivatives was lower than that in the wild type. Nonetheless, these derivative strains were apparently equally motile as the wild type. This indicates that either flagellin is sufficient for cell motility. The immunological activity via Toll-like receptor 5 of the single flagellin-expressing strains or purified single flagellins was readily detectable but mostly variably weaker than that of the wild type. The flagellar filaments of wild type L. agilis BKN88 were more acid-/thermo-stable than those of single flagellin-expressing derivatives. Using a combination of immunoprecipitation and flagellin-specific staining, wild type BKN88 appeared to possess heteropolymeric flagellar filaments consisting of both flagellins and each flagellin appeared to be equally distributed throughout the filaments. The results of this study suggest that the two flagellins together form a more robust filament than either alone and are thus functionally complementary.

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