HYPOTHESIS

Sodium Cycle of Energy Coupling and Cholera

Brown and Sirenko

¹Mechnikov Odessa State University, Central Research Laboratory of the Biology of Cyanobacteria, ul. Petra Velikogo 2, Odessa, 270100 Ukraine; fax: (0482) 23-83-20; E-mail: ibrown@microalgae.odessa.ua

²To whom correspondence should be addressed.

³Institute of Hydrobiology, National Academy of Sciences of Ukraine, ul. Geroev Stalingrada 12, Kiev, 252655 Ukraine.

Submitted September 1, 1995; revision submitted July 26, 1996.

A hypothesis on the appearance and persistence of natural foci of cholera based on ecological and bioenergetic features of the process has been developed. The main causes of persistence and propagation of modern cholera are: 1) inability of various bacteria, including the genus Vibrio and many cyanobacterial species, to perform energy coupling, depending on external conditions, by means of two cycles (the proton and sodium cycles); induction of the sodium cycle of energy coupling increases the resistance of bacteria to various environmental factors, such as high concentrations of sodium, alkaline pH, and a high proton conductance of coupling membranes [1], and probably the virulence of the vibrios; 2) development of cyanobacteria in an aquatic environment enriched with Na⁺ accelerates alkalization of the medium and stimulates the development of the community of cyanobacteria with Vibrio cholerae, an autochthonous inhabitant of saline water bodies and marine shallow waters; 3) salinization of water bodies accelerates their blooming and enriches them with soluble organic matter, a substrate for vibrios inhabiting the biotope; 4) further propagation of cholera infection is related to eating heat-untreated hydrobionts from blooming water bodies [2].

KEY WORDS: cholera, sodium cycle, energy coupling.

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