Current Issues in Molecular Biology

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The Whole Shebang: The Gastrointestinal Tract, Escherichia coli Enterotoxins and Secretion

by J. Daniel Dubreuil

Curr. Issues Mol. Biol. 2012, 14(2), 71-82; https://doi.org/10.21775/cimb.014.071 - 26 Feb 2012

Cited by 2 | Viewed by 936

This review focuses on diarrhea caused by toxins released by enterotoxigenic Escherichia coli. These bacteria are known to produce toxins that have adverse effects on the intestinal tissue in Man and animals. E. coli is contracted through the ingestion of water or food contaminated by this bacterium. Generally, E. coli colonizes the intestinal mucosa where it multiplies and causes damage to the target cells or interferes with the homeostasis that prevails in the gastrointestinal tract. Enteropathogens such as E. coli are only able to exhibit their effects after colonization of the intestinal mucosa from where they release their toxins. These bacteria mainly affect chloride ions secretion through second messenger pathways resulting in secretory diarrhea. In this review, the association of bacteria with the gastrointestinal tract as pathogens and the resulting effects on the various systems of the intestine, including the nervous system and mediators leading to secretion and diarrhea are examined. Full article

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Global Regulatory Pathways and Cross-talk Control Pseudomonas aeruginosa Environmental Lifestyle and Virulence Phenotype

by Kimberly A. Coggan and Matthew C. Wolfgang

Curr. Issues Mol. Biol. 2012, 14(2), 47-70; https://doi.org/10.21775/cimb.014.047 - 22 Feb 2012

Cited by 11 | Viewed by 1515

Abstract

Pseudomonas aeruginosa is a metabolically versatile environmental bacterium and an opportunistic human pathogen that relies on numerous signaling pathways to sense, respond, and adapt to fluctuating environmental cues. Although the environmental signals sensed by these pathways are poorly understood, they are largely responsible for determining whether P. aeruginosa adopts a planktonic or sessile lifestyle. These environmental lifestyle extremes parallel the acute and chronic infection phenotypes observed in human disease. In this review, we focus on four major pathways (cAMP/Vfr and c-di-GMP signaling, quorum sensing, and the Gac/Rsm pathway) responsible for sensing and integrating external stimuli into coherent regulatory control at the transcriptional, translational, and post-translational level. A common theme among these pathways is the inverse control of factors involved in promoting motility and acute infection and those associated with biofilm formation and chronic infection. In many instances these regulatory pathways influence one another, forming a complex network allowing P. aeruginosa to assimilate numerous external signals into an integrated regulatory circuit that controls a lifestyle continuum. Full article

667 KiB

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A Perspective on the Mobilization, Localization and Delivery of Molecules in the Crowded Bacterial Cytoplasm

by J. T. Trevors

Curr. Issues Mol. Biol. 2012, 14(2), 39-46; https://doi.org/10.21775/cimb.014.039 - 16 Nov 2011

Cited by 1 | Viewed by 442

Abstract

It has been assumed that diffusion of molecules in the bacterial cytoplasm is the mechanism that moves molecules in the absence of cytoplasmic streaming. However, is there an undiscovered mechanism present that mobilizes cytoplasm and its molecular contents, and delivers tRNAs to specific ribosomes at specific bacterial cytoplasmic locations? Mobilization of specific tRNA (and also mRNA transcripts and ribosomes) and cell division proteins to specific intracellular locations may suggest that instructions and/or mechanism(s) are needed. The alternative is that molecular crowding in the cytoplasm is sufficient for gentle contact between mRNA, ribosomes and tRNA. Or is it plausible that the bacterial cytoplasm (and its contents) are mobilized with the outcome being more gentle collisions between molecules than by a diffusion only mechanism? One hypothesis is that cytoplasmic and molecule mobilization and spatial organization are possibly driven by the photons in thermal infrared (IR) radiation and generation of exclusion zone (EZ) water in the cytoplasm. Full article

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Curr. Issues Mol. Biol., Volume 14, Issue 2 (July 2012) – 3 articles

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