Cleavage of a Viral Envelope Precursor During the Morphogenesis of Sindbis Virus

In cells infected with a temperature-sensitive mutant of Sindbis virus, the cleavage of the precursor to one of the viral envelope proteins does not occur at the nonpermissive temperature. This precursor is found associated with the plasma membrane fraction obtained from the infected cell. Since this is the site at which the virus matures, this finding suggests that during Sindbis virus replication the precursor to the smaller proteins associates with the cell membrane and is then cleaved during the maturation of the virus.     

Phosphorylated Proteins of Sindbis Virus

The capsid and two membrane proteins of Sindbis virus, grown in chicken cells, contain 0.03 to 0.1 mol of phosphate per mol of protein.     

Proteolytic activity and nitrogen transfer in maize seeds during imbibition

Ethanol-soluble and insoluble nitrogen and protease activity in maize seeds during imbibition period of 6 to 60 h at 30 ± 2 °C were determined both in light and in the dark. In light, soluble and insoluble nitrogen in the embryo were similar to that in the dark. But the increase in soluble nitrogen in the endosperm up to 38 h was higher in light than in the dark. Decrease in insoluble nitrogen was correlated with increase in soluble nitrogen, the level always being higher in the dark. Light increased protease activity also in the endosperm. Among various light qualities, red light was most effective in inducing proteolysis, and loss of nitrogen from the endosperm. Further, the growth and organic nitrogen of primary leaves from seedlings raised from light pretreated seeds were better than those from dark pretreated ones.     

Improvements to solid phase phosphotriester synthesis of deoxyoligonucleotides.

A solution of benzenesulphonic acid (3%, w/v) in a dimethylformamide and dichloromethane mixture (9:1, v/v) is shown to be a very effective reagent for the detritylation of deoxyoligonucleotides attached to a solid support. The levels of depurination with this reagent were lower than those observed with other reagents such as trichloroacetic acid. Coupling reactions are described using above ambient temperatures with no detectable increase in side products. Both procedures have been successfully incorporated into an automated system, which can compete with the rate of synthesis by the phosphite approach.     

Regulation of the carotenoid content and chloroplast development by levulinic acid

Chloroplast development and chlorophyll biosynthesis are co-regulated. To understand the mechanism of regulation of chloroplast biogenesis by chlorophyll, development of the photosynthetic apparatus was monitored during greening of etiolated barley leaf discs in the presence of levulinic acid, an inhibitor of chlorophyll biosynthesis. Although not a direct inhibitor of carotenoid biosynthesis, treatment by levulinic acid resulted in a linear reduction in both chlorophyll and carotenoid contents. Chlorophyll biosynthesis appeared to control that of carotenes. In the presence of levulinic acid, photosystem II (PSII) activity decreased while photosystem I (PSI) activity increased when expressed on a chlorophyll basis. However, the activities of both photosystem I and II decreased when expressed on a per plastid basis. As expected, in the presence of low amounts of chlorophyll, the light-harvesting chlorophyll-protein complex II (LHCPII) was not visible in Coomassie-stained gels in 20 m M levulinic acidtreated tissues, but was detected as a faint band by immunoblotting. This small amount of the LHCPII induced significant amounts of grana stacking, which was monitored as an increase in the ratio of variable to maximum fluorescence. When levulinic acid was washed from the leaf discs and the latter allowed to green in its absence, the chlorophyll and carotenoid contents and the photosynthetic activities approached the control values. Levulinic acid could be used to arrest the light-induced chloroplast development at a desired phase of greening and removed by washing the leaves to restore the developmental process without any apparent toxic effect. Results demonstrate that biosynthesis of carotenes is regulated by that of chlorophylls and extremely low amounts of the LHCPII can induce grana stacking.     

Ethnic differences in regional adiposity between adult caucasian and migrant pakistani males which are unexplained by some common indicators of lifestyles

This paper examined the ethnic differences in regional adiposity, measured as circumferences and skinfolds, after controlling for the effects of some indicators of lifestyle patterns, namely, smoking, physical activity, family history of diabetes and diet, in 262 adult White and 100 migrant Pakistani (of Kashmiri origin) males in Peterborough, East Anglia, England. Amongst individuals regularly consuming various dietary products, Pakistani men had significantly lower mean chest, minimum waist and maximum hip circumferences compared with Caucasians; they also had significantly higher mean abdomen, subscapular and suprailiac skinfolds, but significantly lower mean forearm skinfold. Ethnicity was found to have significant associations with chest (p<0.01), waist (p<0.025), and hip (p<0.05) circumferences; and abdomen (p<0.005), subscapular (p<0.001), suprailiac (p<0.025), midaxillary (p<0.05) and forearm (p<0.005) skinfolds, after removing the combined effects of smoking, physical activity and various dietary products. Results also indicated that migrant Pakistanis had significantly higher mean abdomen (+4.6 mm), subscapular (+5.3 mm), suprailiac (+4.4 mm) and midaxillary skinfolds (+3.3 mm); but significantly lower mean forearm (−1.2 mm) and medial calf (−1.2 mm) skinfolds, and chest circumference (−1.8 cm), after removing the combined effects of age, age², smoking status, physical activity undertaken, diet and family history of diabetes. These significant ethnic differences existed even after removing the effect of body mass index (BMI). This investigation provides clear evidence that the significant ethnic difference in regional adiposity between adult Caucasians and migrant Pakistanis of Kashmiri origin was not due to the various lifestyle indicators but may be influenced by genetic determinants. Further studies are needed to determine the nature and extent of the genetic component of this ethnic heterogeneity in regional adiposity between Caucasians and migrant Pakistanis.     

Catabolite repression vs derepression, an approach to differentiation during sporulation in Bacillus subtilis.

Glutamine, like glucose, repressed sporulation and the synthesis of mycobacillin and dipicolinic acid by Bacillus subtilis, and these syntheses were depressed by dibutyryl cyclic GMP but not by dibutyryl cyclic AMP. Neither of these dibutyryl cyclic nucleotides affected sporulation or a number of spore-associated parameters in the strain under normal physiological conditions. Mutants insensitive to glutamine repression were indifferent to the addition of either of the dibutyryl cyclic nucleotides both in the presence and in the absence of glutamine. Sporulation resulted from the remission of repression obtained under the catabolically active state.     

Propulsion of a fin whale (Balaenoptera physalus): why the fin whale is a fast swimmer

Measurements of an immature fin whale (Balaenoptera physalus), which died as a result of entrapment in fishing gear near Frenchmans Cove, Newfoundland (47 degrees 9' N, 55 degrees 25' W), were made to obtain estimates of volume and surface area of the animal. Detailed measurements of the flukes, both planform and sections, were also obtained. A strip theory was developed to calculate the hydrodynamic performance of the whale's flukes as an oscillating propeller. This method is based on linear, two-dimensional, small-amplitude, unsteady hydrofoil theory with correction factors used to account for the effects of finite span and finite amplitude motion. These correction factors were developed from theoretical results of large-amplitude heaving motion and unsteady lifting-surface theory. A model that makes an estimate of the effects of viscous flow on propeller performance was superimposed on the potential-flow results. This model estimates the drag of the hydrofoil sections by assuming that the drag is similar to that of a hydrofoil section in steady flow. The performance characteristics of the flukes of the fin whale were estimated by using this method. The effects of the different correction factors, and of the frictional drag of the fluke sections, are emphasized. Frictional effects in particular were found to reduce the hydrodynamic efficiency of the flukes significantly. The results are discussed and compared with the known characteristics of fin-whale swimming.