The Escherichia coli OmpR/EnvZ two-component regulatory system, which senses environmental osmolarity, also regulates biofilm formation. Up mutations in the ompR gene, such as the ompR234 mutation, stimulate laboratory strains of E. coli to grow as a biofilm community rather than in a planktonic state. In this report, we show that the OmpR234 protein promotes biofilm formation by binding the cs...

Hyper-osmotic stress strongly induces expression of the Escherichia coli proU operon encoding a high affinity uptake system for the osmoprotectants glycine betaine and proline betaine. Osmoregulation of proU takes place at the transcriptional level by upregulation of the promoter at high osmolarity and repression of transcription by the nucleoid-associated protein H-NS at low osmolarity. In the...

Many maternal disorders that modify the embryonic microenvironment, such as a change in osmolarity, can affect development, but how these changes influence the early embryo remains obscure. Neural tube defects, for example, are common congenital disorders found in fetus and neonates. In this study, we investigated the impact of anisotonic osmolarity (unequal osmotic pressures) on neural tube de...

Because extrafibrillar water content dictates extrafibrillar osmolarity, we aimed to determine the influence of intra- and extrafibrillar fluid exchange on intradiscal pressures and stresses. As experimental results showed that extrafibrillar osmolarity affects intervertebral disc cell gene expression and crack propagation, quantification of the effects of changes in intra- and extrafibrillar f...

BACKGROUND Serum osmolality is an accurate indicator of hydration status in older adults. Glucose, urea, and electrolyte concentrations are used to calculate serum osmolarity, which is an indirect estimate of serum osmolality, but which serum osmolarity equations best predict serum osmolality in the elderly is unclear. OBJECTIVE We assessed the agreement of measured serum osmolality with calc...

The study of the effects of osmolarity and growth phase on Salmonella typhi adherence to and invasion of Henle 407 epithelial cells provides the first evidence of a clear overlap between these two environmental stimuli. High-osmolarity conditions are required in the late-log phase for optimum induction of the adherent and invasive phenotypes.

Alkaline phosphatase, the phoA product, is synthesized constitutively in phoR mutants. This constitutive synthesis, which is independent of phosphate control, varies with changes in the osmolarity of the growth medium; phoA expression increases with increasing osmolarity. Maximum expression of the osmoregulated genes phoA, ompC, and ompF was achieved by osmotic manipulation of minimal medium; c...

OBJECTIVES Dry eye is an important problem in Parkinson's disease (PD) with a potential to affect life quality. Tear osmolarity, accepted as the gold standard in dry eye diagnosis, has not been studied in this subset of patients so far. Therefore, in this study we aimed to evaluate tear osmolarity, Schirmer's test scores and tear film break-up time (TBUT) in PD patients. MA­TE­RI­ALS AND MET­...