A comparison of liquid-holding recovery and photoreactivation in halophilic and non-halophilic bacteria

The ability of the extreme halophile Halobacterium cutirubrum to recover from the effects of ultraviolet radiation during liquid holding in the dark in non-nutrient medium has been compared with that of (i) a moderately halophilic bacterium (NRC 41227) and (ii) Escherichia coli B. The photoreactivabilities of all three bacteria have also been studied. The extreme halophile was incapable of liquid-holding recovery in these conditions, in marked contrast to both E. coli B and the moderate halophile, and also failed to recover when held in nutrient medium in the dark. These results strongly support the hypothesis that H. cutirubrum lacks DNA excision repair. It was also found that ultraviolet-irradiated H. cutirubrum could be almost completely photoreactivated from any level of survival in the range 10(-4)-80%, provided exposure to visible light was not delayed, whereas the moderate halophile resembled E. coli B and had a comparatively limited capacity for photoreactivation.     

The effect of age on enolase turnover in the free-living nematode, Turbatrix aceti.

The rates of synthesis and degradation of enolase and total soluble proteins slow with age in the free-living nematode, Turbatrix aceti. The half-lives are 73 and 58 h for soluble protein and enolase, respectively, in young organisms (5 days old). The respective figures are 163 and 161 h for old organisms (22–30 days old). Similar slowing of protein turnover occurs when the organisms are aged by a repeated screening procedure which avoids the use of fluorodeoxyuridine, an inhibitor of DNA synthesis normally added to aging cultures to obtain synchrony. The results support the idea that slowed protein turnover may be responsible for the formation of altered enzymes in old organisms.     

Tissue distribution of high molecular weight calmodulin-binding protein

Polyclonal antibodies raised against bovine heart high molecular weight calmodulin-binding protein were used to study the distribution of this protein in diverse bovine tissues. The high molecular weight calmodulin-binding protein, in addition to bovine heart, is also present in lung and brain at much lower levels, but not in skeletal muscle, spleen, kidney or uterus.     

Heterogeneity in buffalo lutropin.

Lutropin (LH-1) from water buffaloes has been shown to exhibit microheterogeneity in the N-terminal amino-acid sequence of its alpha-subunit. The beta-subunit did not exhibit such microheterogeneity. Another protocol of purification yielded a preparation of buffalo LH (bu LH-2) different from the buffalo LH-1 in certain physico-chemical properties like ease of dissociation into subunits, sugar composition, isoelectric point, and elution profile on S-200. Data appear to indicate the presence of more than one form of buffalo lutropin.     

Changes in DTPA-iron and management of iron chlorosis in rice nurseries

Summary On a Typic Ustochrept soil incorporation of 10 tons/ha of a green manure plus submergence for 10 days followed by raising upland nursery checked iron chlorosis. In contrast, presubmergence with and without FYM and iron sulfate or pyrite were a failure. Nor weekly sprays with 3.0% iron sulfate were found very effective. The success of green manure plus submergence was associated with the mobilization of soil iron as a result of intense reduction and its subsequent retention in available form at a sufficient high level during the growth of upland nursery.     

Hepatic glycoprotein synthesis in streptozotocin diabetic rats

In vitro incorporation of 3H-mannose into dolichol phosphate mannose, dolichol pyrophosphate oligosaccharides, and secretory and membrane glycoproteins was investigated in liver slices from streptozotocin diabetic rats. In addition, 14C-leucine incorporation into glycoproteins was studied. 3H-mannose incorporation was significantly less in secretory glycoproteins from diabetic rat liver slices than from control tissues, but 14C-leucine incorporation in these proteins was similar in both groups. Dolichol-phosphate mannose and dolichol-phosphate oligosaccharide synthesis were significantly down-regulated in diabetes. When incubated with insulin, mannosylation of secretory proteins, dolichol-phosphate mannose and dolichol-phosphate oligosaccharides reached control levels in three hours. Dolichol-phosphate mannosyltransferase activity was significantly less in diabetes, while in the presence of insulin, the enzyme activity reached control levels in three hours. These results indicate that key intermediates in glycoprotein biosynthesis are regulated by insulin.     

Dolichol synthesis in liver slices of streptozotocin diabetic rats

The rate of dolichol synthesis in normal and diabetic liver slices in the presence or absence of insulin was investigated with radiolabeled acetate and mevalonate as substrates. Cholesterol and dolichol syntheses were found low in diabetic rat liver slices when incubated either with 1-14C-acetate or 2-3H-mevalonate. In the presence of insulin, cholesterol and dolichol synthesis in diabetic rat liver slices returned to normal in nine hours when incubated with 1-14C-acetate; however, with 2-3H-mevalonate, synthesis of cholesterol and dolichol normalized in about three hours. These studies show that dolichol synthesis in rat liver slices is dependent on insulin.