Tracking of thermal microbial shock proteins and genomic variation of Bacillus cereus due to some abiotic stresses.

Bacillus cereus is considered the most potent bacterial strain in terms of the increment in induced proteins during thermal treatment at 52 °C for 90 min. Protein production in food-born microorganism (Bacillus cereus) recovered from contaminated food was investigated in response to heat shock treatment. Bacterial tolerance towards pH, salinity, and temperature at various levels was also investigated. Heat-shock proteins (HSPs) produced when exposed to 52 °C for up to 60 minutes led to significant differences (30%) above the untreated control (37 °C), and the maximum difference was recorded at 52°C at 90 minutes. ISSR detected a higher number of bands/primer than RAPD (13.7 vs. 12.7, respectively), and more polymorphic bands (10.7 vs. 8.4 bands/primer, respectively). The untreated bacterial strain did not grow at pH levels lower than 3, whereas the thermally treated strain grew significantly at pH two. A consistent increase in HSPs was observed, with a gradual increase in salinity of less than 16%. Surprisingly, the gradual increase in temperature did not induce tolerance against higher temperatures. However, a significant growth rate was noticed in response to heat-shocked treatments. The untreated Bacillus cereus demonstrated antibiotic resistance to gentamycin and clindamycin (1.54 and 1.65 cm, respectively), much lower than the corresponding inhibition areas with preheat-treated test pathogen which were recorded (2.37 and 2.49 cm, respectively).

Tracking of thermal microbial shock proteins and genomic variation of Bacillus cereus due to some abiotic stresses / Rastreamento de proteínas de choque microbiano térmico e variação genômica de Bacillus cereus devido a alguns estresses abióticos

Bacillus cereus is considered the most potent bacterial strain in terms of the increment in induced proteins during thermal treatment at 52 °C for 90 min. Protein production in food-born microorganism (Bacillus cereus) recovered from contaminated food was investigated in response to heat shock treatment. Bacterial tolerance towards pH, salinity, and temperature at various levels was also investigated. Heat-shock proteins (HSPs) produced when exposed to 52 °C for up to 60 minutes led to significant differences (30%) above the untreated control (37 °C), and the maximum difference was recorded at 52°C at 90 minutes. ISSR detected a higher number of bands/primer than RAPD (13.7 vs. 12.7, respectively), and more polymorphic bands (10.7 vs. 8.4 bands/primer, respectively). The untreated bacterial strain did not grow at pH levels lower than 3, whereas the thermally treated strain grew significantly at pH two. A consistent increase in HSPs was observed, with a gradual increase in salinity of less than 16%. Surprisingly, the gradual increase in temperature did not induce tolerance against higher temperatures. However, a significant growth rate was noticed in response to heat-shocked treatments. The untreated Bacillus cereus demonstrated antibiotic resistance to gentamycin and clindamycin (1.54 and 1.65 cm, respectively), much lower than the corresponding inhibition areas with preheat-treated test pathogen which were recorded (2.37 and 2.49 cm, respectively).

Bacillus cereus é considerada a cepa bacteriana mais potente em termos de incremento de proteínas induzidas durante o tratamento térmico a 52 °C por 90 min. A produção de proteínas em microorganismos de origem alimentar (Bacillus cereus) recuperados de alimentos contaminados foi investigada em resposta ao tratamento de choque térmico. A tolerância bacteriana ao pH, salinidade e temperatura em vários níveis também foram investigadas. Proteínas de choque térmico (HSPs) produzidas quando expostas a 52 °C por até 60 minutos levaram a diferenças significativas (30%) acima do controle não tratado (37 °C), e a diferença máxima foi registrada a 52 °C em 90 minutos . O ISSR detectou um maior número de bandas/iniciador do que o RAPD (13,7 vs. 12,7, respectivamente) e mais bandas polimórficas (10,7 vs. 8,4 bandas/iniciador, respectivamente). A cepa bacteriana não tratada não cresceu em níveis de pH abaixo de 3, enquanto a cepa tratada termicamente cresceu significativamente em pH dois. Observou-se aumento consistente de HSPs, com aumento gradual da salinidade inferior a 16%. Surpreendentemente, o aumento gradual da temperatura não induziu tolerância a temperaturas mais altas. No entanto, uma taxa de crescimento significativa foi observada em resposta aos tratamentos de choque térmico. O Bacillus cereus não tratado demonstrou resistência antibiótica à gentamicina e clindamicina (1,54 e 1,65 cm, respectivamente), muito menor do que as áreas de inibição correspondentes com patógeno de teste pré-tratado que foram registradas (2,37 e 2,49 cm, respectivamente).