The effect of somatostatins (SRIF-14, 25 and 28), galanin and anti-SRIF on plasma growth hormone levels in Coho salmon (Oncorhynchus kisutch, Walbaum)

Porcine galanin, somatostatins (SRIF-25 and SRIF-28) and invariant SRIF-14, known to have inhibitory-stimulatory actions on growth hormone (GH) secretion in higher vertebrates, were tested for their ability to affect plasma GH levels in coho salmon. Peptides were administered by intraperitoneal injection of 10 or 100 ng g⁻¹ body weight. All three SRIFs decreased plasma GH concentrations, their activity following the order SRIF-14 > SRIF-28 > SRIF-25. Galanin and an anti-SRIF produced pronounced, although transient increases in plasma GH.     

beta-Oxidation and Glyoxylate Cycle Coupled to NADH: Cytochrome c and Ferricyanide Reductases in Glyoxysomes

Glyoxysomes isolated from castor bean (Ricinus communis L., var Hale) endosperm had NADH:ferricyanide reductase and NADH:cytochrome c reductase activities averaging 720 and 140 nanomole electrons/per minute per milligram glyoxysomal protein, respectively. These redox activities were greater than could be attributed to contamination of the glyoxysomal fractions in which 1.4% of the protein was mitochondrial and 5% endoplasmic reticulum. The NADH:ferricyanide reductase activity in the glyoxysomes was greater than the palmitoyl-coenzyme A (CoA) oxidation activity which generated NADH at a rate of 340 nanomole electrons per minute per milligram glyoxysomal protein. Palmitoyl-CoA oxidation could be coupled to ferricyanide or cytochrome c reduction. Complete oxidation of palmitoyl-CoA, yielding 14 nanomole electrons/per nanomole palmitoyl-CoA, was demonstrated with the acceptors, NAL, cytochrome c, and ferricyanide. Malate was also oxidized by glyoxysomes, if acetyl-CoA, ferricyanide, or cytochrome c was present. Glyoxysomal NADH:ferricyanide reductase activity has the capacity to support the combined rates of NADH generation by β-oxidation and the glyoxylate cycle.     

Orientation of electron transport activities in the membrane of intact glyoxysomes isolated from castor bean endosperm

Intact glyoxysomes were isolated from castor bean endosperm on isometric Percoll gradients. The matrix enzyme, malate dehydrogenase, was 80% latent in the intact glyoxysomes. NADH:ferricyanide and NADH:cytochrome c reductase activities were measured in intact and deliberately broken organelles. The latencies of these redox activities were found to be about half the malate dehydrogenase latency. Incubation of intact organelles with trypsin eliminated NADH:cytochrome c reductase activity, but did not affect NADH:ferricyanide reductase activity. NADH oxidase and transhydrogenase activities were negligible in isolated glyoxysomes. Mersalyl and Cibacron blue 3GA were potent inhibitors of NADH:cytochrome c reductase. Quinacrine, Ca²⁺ and Mg²⁺ stimulated NADH:cytochrome c reductase activity in intact glyoxysomes. The data suggest that some electron donor sites are on the matrix side and some electron acceptor sites are on the cytosolic side of the membrane.     

HIV and measures to control infection in general practice.

OBJECTIVE--To assess the impact of HIV on procedures to control infection in general practices. DESIGN--A postal questionnaire survey. SETTING--General practices throughout Britain. SUBJECTS--5359 General practitioners, 3429 (63.9%) of whom returned the questionnaire. MAIN OUTCOME MEASURE--Response to questionnaire on knowledge about HIV and policies for controlling infection. RESULTS--Most doctors (2018) had started to wear gloves when taking blood. Almost half (1510) had not resheathed needles previously but a further 776 had adopted this policy because of HIV. Over half of the doctors did not know or were unsure about the risk of infection from needlestick injuries, and 1759 had no practice policy for controlling infection. CONCLUSIONS--Many doctors are uncertain about measures to control infection in general practice. More information and advice are needed to help doctors develop policies to protect patients and staff.     

MTOCs in higher plant cells: an immunofluorescent study of microtubule assembly sites following depolymerization by APM

Summary A one hour exposure to 3 M amiprophos-methyl (APM) depolymerizes all MT arrays in cells from higher plant suspension cultures. On removal of APM, MT repolymerization sites are detected using immunofluorescent staining. During interphase, Mt arrays return uniformly dispersed across the cell cortex with transverse arrays in elongated cells and random arrays in isodiametric cells. During cell division, MT arrays return as follows: Prophase-MT arrays return in association with the nuclear envelope. Metaphase-MTs return associated with chromosomes. Teleophase-MTs return in apparent association with the reforming nuclear envelope and as aberrant phragmoplasts. MTOCs in higher plant cells may be membrane associated at many stages in the cell cycle. Isolated, condensed chromosomes are capable of nucleating MTs, which can attain small, spindle-like configurations.Abbreviations APM Amiprophos-methyl - MT Microtubule - MTOC Microtubule organizing center - NS Nucleating site     

FURTHER STUDIES ON ASIRACINAE (HOMOPTERA: DELPHACIDAE) IN AUSTRALIA AND NEW CALEDONIA

Abstract
Kiambrama hylonoma gen. n., sp. n., K. longirostrata sp. n. and Notuchus oresbios sp. n. from North Queensland and Notuchoides montanus gen. n., sp. n. from New Caledonia are described. Notuchus palmerstonensis Donaldson is synonymised with N. kurandae Donaldson. A key to genera of Asiracinae in Australia and New Caledonia, keys to species of Kiambrama and Notuchus and new locality records for Notuchus are given.     

Characterization of membrane-bound electron transport enzymes from castor bean glyoxysomes and endoplasmic reticulum

Membranes purified from castor bean endosperm glyoxysomes by washing with sodium carbonate exhibited integral NADH:ferricyanide and NADH:cytochrome c reductase activities. The enzyme activities could not be attributed to contamination by other endomembranes. Purified endoplasmic reticulum membranes also contained the redox activities; and marker enzyme analysis indicated minimum cross contamination between glyoxysomal and endoplasmic reticulum fractions. The glyoxysomal redox activities were optimally solubilized at detergent to protein ratios (weight to weight) of 10 (Triton X-100), 50 (3-[3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate), and 100 (octylglucoside). Detergent in excess of the solubilization optimum was stimulatory to NADH:ferricyanide reductase and inhibitory to NADH:cytochrome c reductase. Endoplasmic reticulum redox activity solubilization profiles were similar to those obtained for glyoxysomal enzymes using Triton X-100. Purification of the glyoxysomal and endoplasmic reticulum NADH:ferricyanide reductases was accomplished using dye-ligand affinity chromatography on Cibacron blue 3GA agarose. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of NADH:ferricyanide reductase preparations purified by rate-zonal density gradient centrifugation, affinity chromatography, and nondenaturing electrophoresis of detergent-solubilized glyoxysomal and endoplasmic reticulum membranes consistently displayed 32- and 33-kDa silver-stained polypeptide bands, respectively.     

Changes in reproductive parameters during the spawning migration of pink salmon, Oncorhynchus gorbuscha (Walbaum)

The hormones 17β-estradiol, 17α-hydroxy-20β-dihydroprogesterone(17α, 20β-P), 11-ketotestosterone, testosterone, gonadotropin and also vitellogenin, were determined during the spawning migration of wild pink salmon in the Fraser and Thompson Rivers in British Columbia. This stock of pink salmon takes approximately 2 weeks to migrate the 333 km upstream to the spawning grounds. Both sexes were at an advanced stage of sexual development when they entered fresh water. In females both the 17β-estradiol and vitellogenin levels fell precipitously during the migration, to be very low at spawning, whereas the 17α,20β-P level rose rapidly, to be highest at arrival on the spawning grounds. The gonadotropin level also rose rapidly during the migration, and was highest in spent fish. Testosterone was at a high level throughout, although this level decreased steadily during migration. In many respects similar endocrine changes were observed in the male. For example, in the case of androgen levels, both testosterone and 11-ketotestosterone fell steadily during migration but were still relatively high at spawning, whereas both gonadotropin and 17α, 20β-P levels rose markedly as migration progress. However, although the qualitative changes were often similar between the sexes, the levels of 17α, 20β-P, testosterone, and gonadotropin were considerably higher throughout in females than in males. It is concluded that this stock of pink salmon is at an advanced stage of sexual development when it enters fresh water. The endocrine changes observed during this study represent those controlling the final stages of reproduction, specifically final oocyte maturation and ovulation in females, and the final stages of spermatogenesis and spermiation in males.