Reactive oxygen species induced by shear stress mediate cell death in Bacillus subtilis.
Exposure of Bacillus subtilis to a shear rate of 1,482/s leads to a rapid loss of cell viability after 10 h of growth. Biochemical and molecular evidences provided below strongly suggest that cell death under high shear results from an apoptosis-like process similar to that described in eukaryotes, with activation of a caspase-3-like protease (C(3)LP) followed by DNA fragmentation. Shear stress leads to an increase in specific intracellular reactive oxygen species (siROS), possibly through activation of NADH oxidase (NOX). The formation of siROS precedes the activation of C(3)LP and DNA fragmentation, thus establishing siROS as the molecular link between shear stress and apoptosis-like cell death. A model is proposed in which NOX is viewed as being strategically placed on the plasma membrane of B. subtilis that senses and converts a mechanical force arising from shear stress into a chemical signal leading to activation of C(3)LP, DNA fragmentation, and thus, apoptosis-like cell death.
Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India.
Susmita
S
Sahoo
K Krishnamurthy
KK
Rao
G K
GK
Suraishkumar
D017209:Apoptosis; D001412:Bacillus subtilis / Q000201:enzymology / Q000254:growth & development / Q000502:physiology*; D019149:Bioreactors / Q000382:microbiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D013058:Mass Spectrometry; D008954:Models, Biological; D009097:Multienzyme Complexes / Q000032:analysis / Q000037:antagonists & inhibitors; D009247:NADH, NADPH Oxidoreductases / Q000032:analysis / Q000037:antagonists & inhibitors; D009861:Onium Compounds / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D033081:Shear Strength; D013314:Stress, Mechanical; D013997:Time Factors
D004791:Enzyme Inhibitors; D009097:Multienzyme Complexes; D009861:Onium Compounds; D017382:Reactive Oxygen Species; C007517:diphenyleneiodonium; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases