[Salivary pH and culture determinations in HIV infected and non-HIV infected patients with oral candidosis].

The aim of the present study was to determine the salivary pH in HIV (Human Immunodeficiency Virus) positive(+) and negative(-) patients and in a control group, for assessing if variations or changes in pH are related to the development of oral candidosis and the species isolated. The sample comprised 120 patients from the Infectology Unit of the Mexico General Hospital, and from the School of Dentistry, UNAM. Three study groups were performed: with oral candidosis HIV+, with oral candidosis HIV-, and a control group.

A mutation in rpoS enhances biofilm formation in Escherichia coli during exponential phase of growth.

Biofilm formation in Escherichia coli is a process that involves slow growth and stress conditions where several molecular signals and growth phase regulated genes are involved. Here we show that rpoS mutant strains (defective in the stress regulator sigma(S)) exhibit an increased production of biofilm, especially in the exponential phase of growth. Our results indicate that rpoS mutants produce an extracellular factor that promotes the production of biofilm during the exponential phase of growth.

Biofilm formation in Escherichia coli is affected by 3-(N-morpholino)propane sulfonate (MOPS).

In most natural environments, association with a surface in a structure known as a biofilm is the prevailing microbial life-style. Escherichia coli has been a useful model for the study of biofilm formation. Here we analyzed the amounts of biofilm formed when E.