Purification and sequence analysis of bioactive atrial peptides (atriopeptins)

Mammalian cardiac atria have several biologically active peptides that exert profound effects on sodium excretion, urine volume, and smooth muscle tone. In the present study two such peptides of low molecular weight were purified and separated from each other on the basis of differences in charge, hydrophobicity, and biological profile. The first peptide, designated atriopeptin I, exhibits natriuretic and diuretic activity and selectivity relaxes intestinal smooth muscle but not vascular smooth muscle strips. The second peptide, atriopeptin II, is a potent natriuretic and diuretic that relaxes both intestinal and vascular strips. Sequence analysis of atriopeptin I indicates that it is composed of 21 amino acids, of which serine and glycine residues predominate. The amino terminal sequence of atriopeptin II up to residue 21 is the same as that of atriopeptin I, with the addition of the Phe-Arg extension at the carboxyl terminus. Both peptides appear to be derived from a common high molecular weight precursor (designated atriopeptigen); their biological selectivity and potency may be determined by the site of carboxyl terminal cleavage.     

Expression, Glycosylation, and Secretion of an Aspergillus Glucoamylase by Saccharomyces cerevisiae

A strain of Saccharomyces cerevisiae capable of simultaneous hydrolysis and fermentation of highly polymerized starch oligosaccharides was constructed. The Aspergillus awamori glucoamylase enzyme, form GAI, was expressed in Saccharomyces cerevisiae by means of the promoter and termination regions from a yeast enolase gene. Yeast transformed with plasmids containing an intron-free recombinant glucoamylase gene efficiently secreted glucoamylase into the medium, permitting growth of the transformants on starch as the sole carbon source. The natural leader sequence of the precursor of glucoamylase (preglucoamylase) was processed correctly by yeast, and the secreted enzyme was glycosylated through both N- and O-linkages at levels comparable to the native Aspergillus enzyme. The data provide evidence for the utility of yeast as an organism for the production, glycosylation, and secretion of heterologous proteins.     

Preliminary meteorological results on Mars from the viking 1 lander

The results from the meteorology instruments on the Viking 1 lander are presented for the first 4 sols of operation. The instruments are working satisfactorily. Temperatures fluctuated from a low of 188 degrees K to an estimated maximum of 244 degrees K. The mean pressure is 7.65 millibars with a diurnal variation of amplitude 0.1 millibar. Wind speeds averaged over several minutes have ranged from essentially calm to 9 meters per second. Wind directions have exhibited a remarkable regularity which may be associated with nocturnal downslope winds and gravitational oscillations, or to tidal effects of the diurnal pressure wave, or to both.     

Somerset: A new chipping potato variety

The Somerset potato variety is a medium-maturing variety with attractive, round to oblong, white-skinned, white-fleshed tubers with shallow eyes. Its major use is expected to be as a chipping variety in areas where potatoes are stored for some length of time, since its sugar content is lower than most varieties during storage, and it can be chipped after six months in storage. Somerset does not show the net necrosis caused by potato leafroll virus, and is immune to race 0 of Phytophthora infestans (late blight). Somerset is also moderately resistant to infection by Alternaria solani (early blight), and is only moderately susceptible to Verticillium wilt. Somerset is more susceptible to both common and acid scab than Superior, but less susceptible than Kennebec and Katahdin. It also has shown susceptibility to skinning and shatter bruise, but does not have a strong blackspot bruise reaction.     

Crop loss prediction tables for potato late blight epidemics

American Journal of Potato Research - The yield loss prediction equation of MacKenzie and Petruzzo was used to determine expected yield losses resulting from over 1000 computer-generated late...     

Effects of an oil-based substrate (The Water Cleanser™) and bacterial additives on nitrogen and phosphorous dynamics in freshwater crayfish (Cherax cainii,Austin and Ryan 2002) aquaculture

Two experiments were conducted to evaluate the efficacy of an oil-based substrate, The Water Cleanser? (TWC). The first experiment studied the effects two substrates of different oil composition (TWC, TWC?+), and a commercial bacterial additive (Bio-Aid) on concentrations of nitrogen and phosphorous in indoor aquaria. The second experiment studied the effects of TWC, a bacterial additive, and a combination (TWC?+?B) on concentrations of nitrogen and phosphorous, phytoplankton abundance and diversity in outdoor freshwater crayfish (Cherax cainii, Austin and Ryan, Invertebr Syst 16:357–367, 2002) tanks. In the first experiment, the concentration of TAN decreased more rapidly with Bio-Aid, whilst the maximum concentrations of NO₂-N and NO₃-N were reduced with the substrates. The concentration of orthophosphate was reduced in aquaria with TWC?+?. In the second experiment, concentrations of TAN, NO₂-N, NO₃-N and total phosphate were not significantly affected by TWC. After addition of TWC?+?B, there was a significant decrease in the concentrations of nitrate and total phosphate, and a higher abundance of phytoplankton was maintained than with other treatments. Additionally, a population Bacillus sp. was found on the substrate surface. TWC had no adverse effects on phytoplankton abundance or diversity, or C. cainii physiology, weight gain or survival. TWC and TWC?+?were effective bioremediators of eutrophic water, whilst a combination of TWC?+?B was effective in short term bioremediation and in promoting phytoplankton abundance in C. cainii tank culture.