Social stimulation and the resumption of copulation in Rhesus (Macaca mulatto) and stumptail (Macaca arctoides) Macaques

Copulatory data derived from observations of social groups of rhesus and stumptail macaques were analyzed to test the hypothesis that pairs of animals would resume copulation significantly sooner if a second male copulated with the female shortly after the first male’s ejaculation. Data from both groups supported the hypothesis. These results, extending previous studies in Macaca nemestrina,suggest that the shortening of copulatory intervals by social stimuli occurs in several species, both in social groups and in experimentally created triads. These findings also are consistent with the hypothesis that socially mediated resumption of mating is related to intrasexual competition among males.     

Identification and characterisation of PmaCI an endonuclease of novel specificity from Pseudomonas maltophila.

We report the use of MonoQ FPLC (Fast Protein Liquid Chromatography) for the rapid purification of a novel Type II restriction endonuclease PmaCI, from Pseudomonas maltophila, which recognises the sequence 5'-CAC decreases GTG-3'. The resulting enzyme is free of other nucleases to a level suitable for its characterisation by multiple-substrate digestion and DNA sequencing techniques. This method appears to be widely applicable and we have used it for the isolation of restriction endonucleases of comparable purity from a range of other organisms. Also described is a rapid method for screening a library of small inserted regions in recombinant M13 molecules for the presence and subsequent screening of restriction sites of interest.     

Synthesis of two diastereoisomeric p-nitrophenyl phosphodiesters of 2'',3''-secouridine and their affinity for phosphodiesterases.

The synthesis of the p-nitrophenyl esters of the 5'- and 3'-phosphates of the nucleoside analogue 2',3'-secouridine are described. Unlike the corresponding diesters of thymidine, these two compounds are diastereoisomers. Their affinity for phosphodiesterases types I and II were investigated. Both analogues were hydrolysed very slowly by snake venom phosphodiesterase but their affinity for the enzyme was similar to that of the p-nitrophenyl ester of thymidine 5'-monophosphate of which they were both competitive inhibitors with Ki approximately Km. Neither compound was hydrolysed by spleen phosphodiesterase but both competitively inhibited the p-nitrophenyl ester of thymidine 3'-monophosphate, with Ki's slightly higher than the Km. Although for each enzyme the Ki of the correct analogue phosphodiester (i.e. the 5'-derivative for snake venom and the 3'-derivative for spleen) was the lower, the absolute specificity seen for the normal substrates had been lost.     

Plant tyrosine decarboxylase can be strongly inhibited by l-α-aminooxy-β-phenylpropionate

The effect of tunicamycin, an inhibitor of N-glycosylation of proteins, on growth and on synthesis of DNA and protein was studied in suspension cultures from Nicotiana tabacum and Catharanthus rosea. In the presence of 0.1–1 g · ml^-1 tunicamycin, cell division and DNA synthesis stopped in cells which had been proliferating logarithmically, but protein formation continued. Cytophotometric determination of the nuclear DNA content in Catharanthus cells showed that a cell-cycle arrest had occurred in G1 phase. Metabolic labelling of cells with the glycoprotein precursors glucosamine or mannose was inhibited, too. The results indicate that one or more glycoproteins are needed for the cell to pass through the G1 phase, as was recently postulated for animal and yeast cells.Abbreviations TCA trichloroacetic acid - TM tunicamycin     

Localization of a substance P-like material in the central and peripheral nervous system of the snail Helix aspersa

Summary A monoclonal antibody against substance P was used for immunocytochemical staining of the central ganglia of the snail Helix aspersa and several peripheral tissues including the gut, reproductive system, cardiovascular system, tentacle and other muscles.Within the central ganglia many neurones, and many fibres in the neuropile and the nerves entering the ganglia, were stained for the SP-like material. The largest numbers of reactive cell bodies were in the pleural ganglia and on the dorsal surfaces of the pedal ganglia. A group of cells was also found, surrounding the right pedal-cerebral connective, that did not fluoresce, but were enveloped by reactive processes terminating directly onto the neurone somata.Specific staining was observed in all peripheral tissues examined and always appeared to be concentrated in nerve terminals. Most particularly these occurred in the heart and aorta, the pharyngeal retractor muscle and the tentacle. Although mostly present in muscular tissues, some fluorescence was also observed in the nervous layer surrounding the retina. The tentacular ganglion also contained immunoreactive cell bodies.     

Identification of the glucose transporter in rat skeletal muscle

The glucose transporter in the plasma membrane of rat skeletal muscle has been identified by two approaches. In one, the transporter was detected as the polypeptide that was differentially labeled by photolysis with [³H]cytochalasin B in the presence of l- and d-glucose. [³H]Cytochalasin B is a high-affinity ligand for the transporter that is displaced by d-glucose. In the other, the transporter was detected by means of its reaction with rabbit antibodies against the purified glucose transporter from human erythrocytes. By both procedures, the transporter was found to be a polypeptide with a mobility corresponding to a molecular weight of 45,000–50,000 upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis.     

Mitogenic response to epidermal growth factor (EGF) modulated by platelet-derived growth factor in cultured fibroblasts

The mitotic effects of epidermal growth factor (EGF) were investigated in two cultured fibroblast lines, BALB/c-3T3 and C3H 10T1/2 cells. EGF (30 ng/ml) added to quiescent 3T3 cells in medium containing either platelet-poor plasma or 10(-5) M insulin caused only minimal increases in the percentage of cells stimulated to initiate DNA synthesis. In contrast, EGF acted synergistically with either insulin or plasma to stimulate DNA synthesis in quiescent cultures of 10T1/2 cells, although the maximum effects of EGF were measured at concentrations several-fold greater than those found in either serum or plasma. In either 3T3 or 10T1/2 cells a transient preexposure to platelet-derived growth factor (PDGF) caused over a 10-fold increase in the sensitivity to the mitogenic effects of EGF. It is therefore possible that a primary action of PDGF is to increase the sensitivity of fibroblasts to EGF, independent of whether EGF alone is found to be mitogenic.     

Observations on the separation of Theileria sporozoites from ticks

Hyalomma anatolicum anatolicum ticks infected with Theileria annulata were partially fed on rabbits and then ground up with tissue culture medium. The ground up ticks were treated by centrifugation at 100 g, filtration through membranes of 8 μm pore diameter and centrifugation on a discontinuous density gradient of Percoll. Counts of sporozoites and tick debris were made from Giemsa stained slides of samples at each stage of the separation. Debris was removed during light centrifugation and filtration at a greater rate than sporozoites. After filtration approximately 41% of the original sporozoites remained in the suspension. After density gradient centrifugation most sporozoites were found in a distinct zone, at approx. 1·08 g/cm³ density, separate from most dense debris and light debris and soluble contaminants. After this final centrifugation approximately 24% of the original sporozoites remained in the recovered suspension.