Ecological studies on streptocephalus dichotomus baird

Summary Streptocephalus dichotomus occurs in a wide variety of shallow andThe maximum period during which these animals occur was 18Studies on both seasonal and day time variations of the physicoThe rate of increase in the population is more or less identical inThe length frequency distribution in the different ponds showsSex ratio does not appear to follow any definite pattern at anyFemales start to bear eggs when 1.7 cm long and the maximumTwo genera, Branchinella kugenumaensis and S. dichotomus were seenThis work formed a part of the thesis submitted for the award of the Degree of     

Changes in Protein Content of Goldfish Optic Nerve During Degeneration and Regeneration Following Nerve Crush

Abstract: After the goldfish optic nerve was crushed, the total amount of protein in the nerve decreased by about 45% within 1 week as the axons degenerated, began to recover between 2 and 5 weeks as axonal regeneration occurred, and had returned to nearly normal by 12 weeks. Corresponding changes in the relative amounts of some individual proteins were investigated by separating the proteins by two-dimensional gel electrophoresis and performing a quantitative analysis of the Coomassie Brilliant Blue staining patterns of the gels. In addition, labelling patterns showing incorporation of [³H]proline into individual proteins were examined to differentiate between locally synthesized proteins (presumably produced mainly by the glial cells) and axonal proteins carried by fast or slow axonal transport. Some prominent nerve proteins, ON1 and ON2 (50–55 kD, pI ～6), decreased to almost undetectable levels and then reappeared with a time course corresponding to the changes in total protein content of the nerve. Similar changes were seen in a protein we have designated NF (～130 kD, pI ～5.2). These three proteins, which were labelled in association with slow axonal transport, may be neurofilament constituents. Large decreases following optic nerve crush were also seen in the relative amounts of α- and β-tubulin, which suggests that they are localized mainly in the optic axons rather than the glial cells. Another group of proteins, W2, W3, and W4 (35–45 kD, pI 6.5–7.0), which showed a somewhat slower time course of disappearance and were intensely labelled in the local synthesis pattern, may be associated with myelin. A small number of proteins increased in relative amount following nerve crush. These included some, P1 and P2 (35–40 kD, pIs 6.1–6.2) and NT (～50 kD, pI ～5.5), that appeared to be synthesized by the glial cells. Increases were also seen in one axonal protein, B (～45 kD, pI ～4.5), that is carried by fast axonal transport, as well as in two axonal proteins, HA1 and HA2 (～60 and 65 kD respectively, pIs 4.5–5.0), that are carried mainly by slow axonal transport. Other proteins, including actin, that showed no net changes in relative amount (but presumably changed in absolute amount in direct proportion to the changes in total protein content of the nerve), are apparently distributed in both the neuronal and nonneuronal compartments of the nerve.     

Microbodies (peroxisomes) in the toad,Bufo marinus

Summary Microbodies (peroxisomes), a group of cytoplasmic organelles enriched in catalase, are demonstrated in the toad, Bufo marinus, by light and electron microscopy by means of a cytochemical staining procedure that demonstrates the peroxidatic activity of catalase with diaminobenzidine (DAB). Amphibian microbodies are similar to those of other classes in their fine structure and localization in hepatocytes and kidney, where they are prominent in the proximal tubular cells. Nucleoids are present only in renal microbodies. In the proximal renal tubule an unusual group of large brown granules are identified as lysosomes by their acid phosphatase, -glucosaminidase and -glucuronidase activities.This work was supported by U.S. Public Health Service Grants Nos. NS-06856 and HD 00674. We wish to thank Dr. Richard M. Hays who generously supplied us with toads; Dr. Alex B. Novikoff for making available facilities for ultramicrotomy, Miss Betty De Prest for technical assistance; Miss Marianne Van Hooren for preparation of the photomicrographs.     

The effect of 4-isothiocyanatobenzene sulfonic acid on the oxygen affinity of human hemoglobin

Human hemoglobin reacts with 4-Isothiocyanatobenzene sulfonic acid at the four amino groups of the N-terminal valines. The modified protein shows a decreased oxygen affinity over a wide pH range, a reduced alkaline Bohr effect, decreased co-operativity, and a reduced effect of inositol hexasulfate on the oxygen affinity.     

Forebrain projections of the pigeon olfactory bulb

The olfactory system of the pigeon (Columba livia) was examined. Our electrophysiological and experimental neuroanatomical (Fink-Heimer technique) data showed that axons from the olfactory bulb terminated in both sides of the forebrain. The cortex prepiriformis (olfactory cortex), the hyperstriatum ventrale and the lobus parolfactorius comprised the uncrossed terminal field. The crossed field included the paleostriatum primitivum and the caudal portion of the lobus parolfactorius, areas which were reached through the anterior commissure. In this report the relationships between areas that receive olfactory information and the possible roles that olfaction plays in the birds' behavior are discussed.     

Genome‐wide association study identifies loci associated with liability to alcohol and drug dependence that is associated with variability in reward‐related ventral striatum activity in African‐ and European‐Americans

Genetic influences on alcohol and drug dependence partially overlap, however, specific loci underlying this overlap remain unclear. We conducted a genome‐wide association study (GWAS) of a phenotype representing alcohol or illicit drug dependence (ANYDEP) among 7291 European‐Americans (EA; 2927 cases) and 3132 African‐Americans (AA: 1315 cases) participating in the family‐based Collaborative Study on the Genetics of Alcoholism. ANYDEP was heritable (h ² in EA = 0.60, AA = 0.37). The AA GWAS identified three regions with genome‐wide significant (GWS; P < 5E‐08) single nucleotide polymorphisms (SNPs) on chromosomes 3 (rs34066662, rs58801820) and 13 (rs75168521, rs78886294), and an insertion‐deletion on chromosome 5 (chr5:141988181). No polymorphisms reached GWS in the EA. One GWS region (chromosome 1: rs1890881) emerged from a trans‐ancestral meta‐analysis (EA + AA) of ANYDEP, and was attributable to alcohol dependence in both samples. Four genes (AA: CRKL, DZIP3, SBK3; EA: P2RX6) and four sets of genes were significantly enriched within biological pathways for hemostasis and signal transduction. GWS signals did not replicate in two independent samples but there was weak evidence for association between rs1890881 and alcohol intake in the UK Biobank. Among 118 AA and 481 EA individuals from the Duke Neurogenetics Study, rs75168521 and rs1890881 genotypes were associated with variability in reward‐related ventral striatum activation. This study identified novel loci for substance dependence and provides preliminary evidence that these variants are also associated with individual differences in neural reward reactivity. Gene discovery efforts in non‐European samples with distinct patterns of substance use may lead to the identification of novel ancestry‐specific genetic markers of risk.