Effects of ethanol and naltrexone on aggressive display in the siamese fighting fish, Betta splendens

The present study used the aggressive display of Betta splendens in response to a mirror as an index of the effects of ethanol and the opiate antagonist, naltrexone. Naltrexone produces an opiate receptor blockade and thus provided a test of the hypothesis that ethanol effects on aggression are mediated by the opioid system. Eighty fish were randomly assigned to one of eight groups in a 4 X 2 factorial design with Ethanol (0, 0.25, 0.50, and 0.75 g%) and Naltrexone (0 and 5 mg/l) as the main factors. The 0.75 g% dose of ethanol reliably suppressed aggressive display as measured by number of gill show responses, but lower doses had no effect or tended to increase aggressive display. At the same time, all doses of ethanol increased arousal in the fish as measured by airgulping. Naltrexone alone did not have effects on aggression or arousal, and did not interact with ethanol on either measure. Thus the results did not support the ethanol-opioid common-link hypothesis.

Nucleotide sequence of the structural glycoprotein VP7 gene of Nebraska calf diarrhea virus rotavirus: comparison with homologous genes from four strains of human and animal rotaviruses

A full-size cloned cDNA copy of the rotavirus gene encoding the structural neutralization glycoprotein (VP7) of Nebraska calf diarrhea virus (NCDV), a strain recently shown to be effective as a vaccine in children, has been sequenced. Comparison of the deduced amino acid sequence of NCDV (serotype 6) VP7 with that of four other rotavirus strains (human WA serotype 1, human HU-5 serotype 2, simian SA-11 serotype 3, and bovine UK serotype 6) indicates that the degree of amino acid homology among VP7 neutralization proteins of these serotypes ranges from 75 to 86%. Four hydrophilic regions at amino acid residues 174-183, 248-256, 287-294, and 310-317 exhibit significant homology and hence may represent common antigenic determinants, while one hydrophilic area at amino acid residues 83-102 exhibits sufficient divergence to suggest it may be involved in serotype specificity.

Membrane sterols and the development of the preimplantation mouse embryo

The role of membrane sterols in the compaction and subsequent development of the preimplantation mouse embryo was studied by incubating embryos in 7-ketocholesterol and other oxygenated sterols. These sterols have been shown to inhibit sterol synthesis and deplete membranes of cholesterol in a variety of ther cell types. Compaction and subsequent blastocyst formation were normal when embryos were incubated in physiological sterols but were inhibited by oxygenated sterols to a degree which depended upon the concentration of sterol, duration of incubation and developmental age of the embryos. Precompaction 8-cell embryos were most susceptible to the action of these sterols and failed to compact (as assessed by cell flattening and increased intercellular adhesion) but continued to divide, whilst later stage embryos developed normally, 7-ketocholesterol had a specific effect on the ultrastructure of the smooth endoplasmic reticulum of treated embryos. The developmental and ultrastructural effects induced by the oxygenated sterols could be reversed or prevented by the use of products of the blocked reaction (i.e. mevalonate, desmosterol or cholesterol). These results substantiate the evidence that preimplantation mammalian embryos are capable of synthesizing membrane sterols from the 8-cell stage onwards and emphasize the importance of the sterol composition of membranes for normal cytokinesis and compaction of the mouse embryo.

Effects of excess vitamin A on the cranial neural crest in the chick embryo

Experiments on fertile hens' eggs have shown that an excess of vitamin A has a highly specific effect on the migration of cranial neural crest cells in the early stages of chick embryogenesis. Migration is disrupted and retarded. This is consistent with the causal mechanism proposed by Poswillo for the Treacher Collins syndrome.

Identification of the 5' end of Rous sarcoma virus RNA

The 5'-terminal triphosphate of the 35S RNA isolated from Rous sarcoma virus is blocked by 7-methylguanosine in 5' linkage with the penultimate nucleoside which is methylated in the 2'-O-ribose position, a type of endgroup found in all animal mRNAs investigated during the past year. The specific nuclease-resistant terminal fragment of RSV RNA has the structure 7mG5'ppp5'GmpCp-. This finding supports the belief that RNA of Rous sarcoma virus represents a (+) strand messenger which may be directly translated upon infection.

Characterization of the end groups of RNA of Rous sarcoma virus

The 3' terminus of the 30-35S RNA of Rous sarcoma virus is adenosine. Its amount indicates an average molecular weight for that RNA of about 3 x 10(6). The 5' terminus of 30-35S RNA of Rous sarcoma virus was not di- or triphosphorylated, whether isolated by the standard procedure or from virus collected within 3 min of its release from the cells.

Hyperthermia as a teratogenic agent

The common cotton-eared marmoset, a nonhuman primate with a narrow zone of thermoneutrality, was used in an experiment to assess the effects of hyperthermia as a teratogenic agent. Mild heat stress conditions were used. The results of this preliminary study justify further investigation of the effect of hyperthermia on the primate embryo during morphogenesis.