Molecular Mechanisms of Microbial Survival in Foods

Diez-Gonzalez, Francisco; Kuruc, Julie

doi:10.1128/9781555815479.ch8

Cited by 1 publication

(1 citation statement)

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“…These results indicate that salinity and temperature tolerance mechanisms may be coupled at the molecular level, consistent with the findings of previous studies demonstrating that pre-exposure to osmotic stress increased the tolerance to heat stress in V. vulnificus (Rosche et al, 2005). Such coupling may result from temperature and salinity responses using common molecular pathways such as the SOS response pathway, the heat-shock response pathway and the general stress response pathway (Hengge-Aronis, 2002;Diez-Gonzalez and Kuruc, 2009). However, Rosche et al (2005) have demonstrated that the cross-protection between osmolarity and heat in V. vulnificus is independent of rpoS, the master regulator of the general stress response mechanism, and were unable to elucidate the origin of this cross-protection.…”

Section: Discussionsupporting

confidence: 80%

Shape and evolution of the fundamental niche in marine Vibrio

et al. 2012

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Hutchinson’s fundamental niche, defined by the physical and biological environments in which an organism can thrive in the absence of inter-species interactions, is an important theoretical concept in ecology. However, little is known about the overlap between the fundamental niche and the set of conditions species inhabit in nature, and about natural variation in fundamental niche shape and its change as species adapt to their environment. Here, we develop a custom-made dual gradient apparatus to map a cross-section of the fundamental niche for several marine bacterial species within the genus Vibrio based on their temperature and salinity tolerance, and compare tolerance limits to the environment where these species commonly occur. We interpret these niche shapes in light of a conceptual model comprising five basic niche shapes. We find that the fundamental niche encompasses a much wider set of conditions than those strains typically inhabit, especially for salinity. Moreover, though the conditions that strains typically inhabit agree well with the strains’ temperature tolerance, they are negatively correlated with the strains’ salinity tolerance. Such relationships can arise when the physiological response to different stressors is coupled, and we present evidence for such a coupling between temperature and salinity tolerance. Finally, comparison with well-documented ecological range in V. vulnificus suggests that biotic interactions limit the occurrence of this species at low-temperature—high-salinity conditions. Our findings highlight the complex interplay between the ecological, physiological and evolutionary determinants of niche morphology, and caution against making inferences based on a single ecological factor.

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