Scanning electron microscopy study of hair shaft changes related to hardness of water.

INTRODUCTION AND AIMS: Brittleness and breakage of hair is a common complaint in the geographical area of Saudi Arabia where we work. This area has a high level of hardness in normal tap water. We aimed to study and compare structural differences and relative deposition of calcium and magnesium salts on the hair shaft surface using scanning electron microscopy (SEM) between hair shaft samples from normal, healthy volunteers treated with hard and soft water. METHODS: Hair samples obtained from 20 healthy volunteers were divided into two groups. One group was treated with hard water for 3 weeks and the second with soft water for the same duration. SEM was used to assess hair shaft surface damages and relative deposition of calcium and magnesium on the surface of the hair. RESULTS: There was no statistically significant difference between the study and control group as far as surface changes under SEM were concerned. As far as the relative deposition of calcium and magnesium was concerned, there was no statistically significant difference in calcium deposition between the control and study samples (P = 0.28). On the other hand, magnesium deposition showed a significant difference between both groups (P = 0.001), with a higher level in samples washed with hard water. CONCLUSIONS: Hard water may be associated with increased deposits on the hair shaft surface, however, this does not necessarily translate into evident structural surface changes, as evidenced by SEM.

Creation of salt-insensitive 3'(2'),5'-bisphosphate nucleotidase by modeling and mutagenesis approach.

3'(2'),5'-Bisphosphate nucleotidase, (EC 3.1.3.7) (BPntase) is a ubiquitous enzyme. Recently, these enzymes have drawn considerable attention as in vivo targets of salt toxicity as well as therapeutic targets of lithium that is used for the treatment of manic-depressive disorders. They belong to the Mg2+-dependent Li+-sensitive phosphomonoesterase super-family and are highly sensitive to lithium and sodium ions. However, the molecular mechanism of inhibition of this group of enzymes by monovalent cations has not been completely understood. Previously we have identified a BPntase (Dhal2p) from a highly halotolerant yeast Debaryomyces hansenii. Molecular characterization revealed a number of unique features in Dhal2p, indicating this is an extraordinary member of the family. In this study, we have carried out the structure-function analysis of Dhal2p through the combination of molecular modeling and in vitro mutagenesis approach. We have not only provided the explanation for the role played by the functionally important elements that are conserved among the members of this family but also identified important, novel structural elements in this enzyme. Our study for the first time unraveled the role of a flap as well as a loop region in the functioning of this enzyme. Most importantly, mutations in the loop region resulted in the creation of a BPntase that was insensitive to salt.