The multiple-minima problem in small peptides revisited. The Threshold Accepting approach.

A recently reported optimization method, known as Threshold Accepting, was tested for the purpose of locating the structure of several peptide molecules with the lowest conformational energy. A comparison with previous results obtained with the Simulated Annealing technique was made. Our study indicate Threshold Accepting as a better technique in locating such structures.     

Effect of chronic ingestion of iodide during pregnancy and lactation on rat pup brain enzymes

The developmental pattern of several key enzymes in brain of pups born to mothers receiving high levels of iodide (1.1 mg daily intake) during pregnancy and lactation were followed up to the weaning period. We found that in the initial states of postnatal development, glutamic dehydrogenase increased above control levels, whereas succinic dehydrogenase decreased. At late stages, we observed differences in phosphofructokinase and malic enzyme activities which were all increased at 30 days. There was no change in hexokinase. Animal weight did not vary with respect to controls and we only obtained discrete increases (not statistically different) in serum thyroxine values, which led us to assume that the enzymatic modifications might be a consequence of either a very mild hormonal alteration or to the direct effect of iodide.     

Suicide vector for transposon mutagenesis in Pseudomonas solanacearum.

A suicide vector was constructed by cloning the transfer genes of the wide-host-range (IncW group) plasmid R388 into the BamHI site of pBR325. This plasmid can deliver Tn5 into Pseudomonas solanacearum at frequencies ranging from 10(-6) to 10(-9) per recipient.     

A comparative study of salivary secretion by parotid and mandibular glands of anaesthetized Capra hircus: effect of pilocarpine

A study was made of basal secretion and the effect of the infusion of pilocarpine on the flow and composition of saliva in the parotid and mandibular glands of the anaesthetized lactating goat. In the parotid gland there was a basal flow (1.6 +/- 0.29 microliter/min) which was not present in the mandibular gland. There is a statistically significant dose-effect relationship between pilocarpine and salivary flow in both glands. Salival composition and its variation with respect to the flow of saliva did not conform to either of the two glands to an exclusive monogastric or ruminant model.     

Glycosyl acceptors in intact and permeabilized normal and cystic fibrosis fibroblasts

Using cell permeabilization, a technique which allows addition of exogenously supplied radiolabeled sugar nucleotides to serve as direct glycosyl donors, oligosaccharide biosynthesis was examined in fibroblasts obtained from normal and cystic fibrosis (CF) subjects. Incubation of logarithmically growing cells with either radiolabeled leucine or xylose has indicated that there was a difference in the synthetic rate between the cell types. Protein synthesis in normal cells made permeable with 50 m?g/ml lysolecithin (LL) was demonstrated to be absent, and could not be induced to take place by adding exogenous components, including energy sources and amino acids, normally required for protein synthesis. Thus radiolabeled sugars were being added to peptide acceptors which were already present at the time of LL addition. Both permeable and intact fibroblasts were exposed to labeled UDP-xylose, UDP-galactose, and UDP-glucuronic acid, all donors of mucopolysaccharide precursors. The uptake of xylose into protein was the same for both normal and CF cells, but permeable CF fibroblasts incorporated statistically greater amounts of sugar from UDP-galactose and UDP-glucuronic acid. Intact CF cells were also labeled using these two sugar nucleotides. Trypan blue exclusion indicated CF and normal fibroblasts were equally intact. This and the fact that preincubation of CF cells with the appropriate cold sugar nucleotide eliminated the differences in incorporation between the normal and CF cells suggested that CF fibroblasts had more cell surface acceptor than the normal cells.     

Succulence and CAM relationships in Aeonium genus

The CAM has been tested in six species of the Aeonium genus by studying the diurnal fluctuation of organic acids, pH and night fixation of CO₂. The existence of a mesophyll structure able to support this metabolism has been shown as well as a congruent periodicity in the pool of cell starch. We have calculated the S, ES and Sm indices in the six species. A series of regression equations of different grades and types were calculated and shown to have correlation coefficients statistically significant. This allows us to confirm the suitability of the Sm index as a rapid test to establish the CAM as postulated by former authors.