The importance of Paracallisoma coecus and myctophid fishes to nesting fork-tailed and Leach's storm-petrels in the Queen Charlotte Islands, British Columbia

The diet of fork-tailed (Oceanodroma furcata) and Leach's storm-petrel(O.leucorhoa) was studied at Petrel Island, a small island northof Hippa Island in the Queen Charlotte Islands, British Columbiain 1983. The diet of the two storm-petrel species consistedmostly of the amphipod Paracallisoma coecus and fish. Most fisheswhich could be identified were myctophids, and may have beenacquired by storm-petrels at night. Fishes increased while P.coecusdeclined in importance as a food over the nestling season ofthe storm-petrels. The amount of oil also declined in the Leach'sstorm-petrel diet over the season. Since P.coecus contains muchoil, the seasonal decline of both P.coecus and oil was probablyassociated. Other less important foods were jellyfishes, copepods,isopods, euphausiids, shrimp, squid and octopus. Jellyfishes(Velella velella) only occurred in the diet of Leach's storm-petrels,which may relate to that storm-petrel feeding in open oceanwhere V. velella occurs most frequently. The most numerous copepodwas Neocalanus cristatus, which was only observed in the storm-petreldiet early on during the study period. An abyssal copepod, Bathycalanusbradyi, and the isopod Cirolana californiensis (tentativelyidentified, the latter only previously known from sea canyonsoff California) were surprising food items of storm-petrels.Most euphausiid prey consisted of Thysanoessa spinifera andEuphausia pacifica.     

Species-specific effects of bombesin on gastric emptying and neurohypophyseal secretion

Previous reports have demonstrated that systemic injection of cholecystokinin (CCK) in rats produces dose-related decreases in food intake, increases in neurohypophyseal secretion of oxytocin (OT), and decreases in gastric emptying. The present studies determined whether systemic injection of bombesin (BBS), another peptide that potently reduces food intake in rats, had similar effects on OT secretion and gastric emptying. Although BBS produces a dose-dependent inhibition of food intake, even very high doses did not significantly affect plasma OT levels and only slightly decreased rates of gastric emptying. Consequently, despite their similar inhibitory effects on food intake, BBS does not appear to activate the same network of central nervous system pathways as does CCK in rats. However, parallel studies in monkeys demonstrated that systemic injection of BBS was effective in stimulating neurohypophyseal secretion of vasopressin rather than OT, in a pattern both qualitatively and quantitatively analogous to the effects of CCK in this species. Together with previous findings that BBS more potently inhibits gastric emptying in primates than in rats, these results therefore also suggest the presence of significant species differences in the central mechanisms by which BBS acts to reduce food intake.     

Ac transposition in transgenic tomato plants

Summary As an initial step towards developing a transposon mutagenesis system in tomato, the maize transposable element Ac was transformed into tomato plants via Agrobacterium tumefaciens. Southern analysis of leaf tissue indicated that in nine out of eleven transgenic plants, Ac excised from the T-DNA and reintegrated into new chromosomal locations. The comparison of Ac banding pattern in different leaves of the same primary transformant provided evidnece for transposition during later stages of transgenic plant development. There was no evidence of Ds mobilization in tomato transformants.     

Immunocytochemical localization of aldolase in normal, denervated, and dystrophic chicken muscles

To investigate whether immunocytochemical localization of muscle-specific aldolase can be used for fiber phenotype determination, we produced specific antibodies against the enzyme and studied its distribution in adult chicken skeletal muscles by indirect immunofluorescence microscopy. Monoclonal antibodies against the myosin heavy chains of fast-twitch (MF-14) and slow-tonic (ALD-58) muscle fibers were also used to correlate aldolase levels with the fiber phenotype. The goat anti-aldolase antibody was found to be specific for the A form of aldolase, as evidenced by sodium dodecyl sulfate gel electrophoresis, immunotitration experiments, and immunoblot analysis. The antibody reacted strongly with the fast-twitch myofibers of normal pectoralis and posterior latissimus dorsi muscles; the phenotype of these muscle fibers was confirmed by a positive immunofluorescent reaction after incubation with MF-14 antibody. By contrast, the slow-tonic myofibers of normal anterior latissimus dorsi, which react positively with ALD-58 antibody, reacted weakly with anti-aldolase antibodies. In denervated chicken muscles, reaction to anti-aldolase antibodies was markedly reduced in fast-twitch fibers, although reaction to MF-14 was not diminished. By contrast, in dystrophic muscle, fast-twitch fibers showed reduced reactivity to anti-aldolase and marked to moderate reduction in MF-14 reactivity. Our results show that: (a) in normal muscles, reactivity to anti-aldolase matches the phenotype obtained by using anti-fast or anti-slow myosin heavy chain antibodies, and therefore can serve to identify mature fibers as fast or slow; and (b) in denervated or dystrophic muscles, the intracellular expressions of aldolase and fast-twitch myosin heavy chains are regulated independently.     

Salicyloylaspartate as an endogenous component in the leaves of Phaseolus vulgaris

An amide conjugate of o-methoxybenzoic acid and aspartic acid has been isolated from bean leaves. After extraction and methylation of plant material, this compound was isolated as two isomeric monoethyl monomethyl esters. The ethylation of the aspartyl carboxyl groups was shown to be a likely result of an extraction procedure utilising acidified ethanol, the methylation of the aromatic hydroxy of the methoxy group to be due to the derivatisation procedure. Studies with pentafluorobenzylation confirmed that the endogenous compound is o-hydroxybenzoylaspartate.     

Simultaneous degradation of the herbicides 2,4-dichlorophenoxyacetic acid and 2-(2-methyl-4-chlorophenoxy)propionic acid by mixed bacterial cultures

The simultaneous degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-(2-methyl-4-chlorophenoxy)propionic acid (mecoprop) was achieved by two mixed cultures in the absence of any additional carbon or energy substrates. Mecoprop was not completely degraded by either of the two cultures, nor did addition of 2,4-D affect the degradation of mecoprop. The cultures completely degraded 2,4-D, and the degradation was uninfluenced by the addition of mecoprop. Nearly complete dechlorination of the mixture of two herbicides was achieved by both cultures, on the basis of the total amount of the two herbicides degraded. During the course of the reaction, however, the expected values of chloride were not met. Cell growth continued after the degradation of the parent substrates ceased. Although the mecoprop degradation did not continue to completion, spectral and growth data indicated that the metabolites which had accumulated during the reaction were degraded upon further incubation.     

Myosin heavy chain expression during development and following denervation of fast fibers in the red strip of the chicken pectoralis

The myosin heavy chain composition of muscle fibers that comprise the red strip of the pectoralis major was determined at different stages of development and following adult denervation. Using a library of characterized monoclonal antibodies we found that slow fibers of the red strip do not react with antibodies to any of the fast myosin heavy chains of the superficial pectoralis. Immunocytochemical analysis of the fast fibers of the adult red strip revealed that they contain the embryonic fast myosin heavy chain rather than the adult pectoral isoform found throughout the adult white pectoralis. This was confirmed using immunoblot analysis of myosin heavy chain peptide maps. We show that during development of the red strip both neonatal and adult myosin heavy chains appear transiently, but then disappear during maturation. Furthermore, while the fibers of the superficial pectoralis reexpress the neonatal isoform as a result of denervation, the fibers of the red strip reexpress the adult isoform. Our data demonstrate a new developmental program of fast myosin heavy chain expression in the chicken and suggest that the heterogeneity of myosin heavy chain expression in adult fast fibers results from repression of specific isoforms by innervation.     

Haematological cell proliferation and differentiation responses to perturbations of polyamine biosynthesis

Combined administration of methylglyoxal-bis-guanylhydrazone (MGBG) (25 mg/kg) with difluoromethylornithine (DFMO), or MGBG alone at a higher dose (50 mg/kg), to mice resulted in a decreased white cell count (WBC) in the peripheral blood while DFMO or MGBG alone at a lower dose (25 mg/kg) had no effect. As expected, DFMO alone increased the number of colony forming units spleen (CFU-s), colony forming units diffusion chamber granulocyte (CFU-dg) and colony forming units culture (CFU-c) in the bone marrow. MGBG treatment led to an increase in CFU-dg alone. Combined treatment seemingly had no effect on marrow stem cells. Total tibial and differential counts were not affected by any of the treatments. Cell proliferation in diffusion chamber cultures, as judged by CFU-dg colony formation, was impaired by MGBG alone or in combination with DFMO, at dose levels which had no effect or increased the precursor cell number in the bone marrow. This effect was partially reversed with either putrescine or spermidine. Determination of intracellular polyamine concentrations, demonstrated decreased putrescine and spermidine levels after DFMO administration. As expected, MGBG treatment resulted in decreased spermidine and spermine levels, concomitant with an increase in putrescine. In mice which received both agents, rather than only MGBG, after 3 days higher intracellular polyamine concentrations were observed. After 11 days, however, there was no significant difference between the two groups.     

The equine protease inhibitory system (Pi): Abnormal expressions of PiF,PiL, and PiS

Three cases of abnormal expression of the equine protease inhibitory alleles, Pi F, L, and S₁, were observed following the examination of 30,000 plasma samples by one-dimensional acid (pH 4.6) polyacrylamide gel electrophoresis. Characterization of the abnormal proteins in terms of isoelectric point, molecular mass, inhibitory spectra, and sialic acid content was performed using one- and two-dimensional electrophoretic techniques. The Pi F and S₁ abnormalities were postulated to be the result of amino acid substitutions causing alterations in the processing of the carbohydrate side chains. No explanation could be offered for the Pi L abnormality other than a charge shift mutation. Abnormal types, F*, L*, and S*₁ behaved as alleles but the distribution of L* in offspring from one stallion (present in only 6 of 83 offspring) differed significantly from expectation.This work was supported by a grant from the Australian Stud Book, Alison Road, Randwick, N.S.W. 2031.     

Polyamine depletion following exposure to DL-alpha-difluoromethylornithine both in vivo and in vitro initiates morphological alterations and mitochondrial activation in a monomorphic strain of Trypanosoma brucei brucei

DL-alpha-difluoromethylornithine (DFMO), a specific irreversible inhibitor of ornithine decarboxylase (ODC), rapidly depletes cells of intracellular putrescine. When administered to animals and humans, DFMO cures acute infections of trypanosomiasis. In order to determine if the mechanism of drug action is related to initiation of transformation and biochemical alterations subsequent to polyamine depletion, trypanosome morphology and mitochondrial activation were studied in a monomorphic strain of Trypanosoma brucei brucei. Exposure of trypanosomes to DFMO in vivo in infected rodents or in vitro in culture resulted in a depletion of intracellular putrescine and a cessation of cell division without specific cytotoxicity. These events were followed by a transformation of the long slender bloodstream form to a short stumpy form via an intermediate morphology. Putrescine, the product of the ODC reaction, abrogates this effect. When introduced into SDM-79 medium, the intermediate form is capable of further transformation to an "insect" procyclic trypomastigote whereas the long slender form and short stumpy form are not. Short stumpy forms are incapable of binary fission and have lost their infectivity for the vertebrate host. In addition, the mitochondrial marker enzyme, NAD diaphorase, was found only in the short stumpy and intermediate forms. We hypothesize that the short stumpy phenotype may not be a viable stage in the natural transformation of the trypanosome from its mammalian host to the insect vector.