Green-backed herons (Butorides striatus) possibly using a lure and using apparent bait

Zusammenfassung In Burkina Faso ließ ein Mangrovereiher offensichtlich gezielt eine Asclepiadaceen-Blüte aus 20 cm Höhe auf die Wasseroberfläche fallen und verharrte danach einige Sekunden mit halb-gestrecktem Hals. Bei einer weiteren Beobachtung in Niger plazierte ein Mangrovereiher einen kleinen Gegenstand auf der Wasseroberfläche. Bevor der Gegenstand mit dem Wind außer Reichweite trieb, holte ihn der Reiher und legte ihn auf der Luvseite wieder auf der Wasseroberfläche ab. Der Vorgang wiederholte sich mehrere Male, dabei gelang es dem Reiher, einen Fisch zu erbeuten, der allerdings wieder entkam. Anderntags setzte an derselben Stelle ein Mangrovereiher in gleicher Weise offensichtlich einen Käfer ein. Ähnliche Beobachtungen werden kurz diskutiert.     

Ammonium uptake in Rhodopseudomonas capsulata

Investigations of the uptake of ammonium (NH ₄ ⁺ ) by Rhodopseudomonas capsulata B100 supported the presence of an NH ₄ ⁺ transport system. Experimentally NH ₄ ⁺ was determined by electrode or indophenol assay and saturation kinetics were observed with two apparent K _m's of 1.7 M and 11.1 M (pH 6.8, 30°) and a V _max at saturation of 50–60 nmol/min·mg protein. The optimum pH and temperature were 7.0 and 33° C, respectively. The Q₁₀ quotient was calculated to be 1.9 at 100 M NH ₄ ⁺ , indicating enzymatic involvement. In contrast to the wild type, B100, excretion of NH ₄ ⁺ , not uptake, was observed in a glutamine auxotroph, R. capsulata G29, which is derepressed for nitrogenase and lacks glutamine synthetase activity. G29R1, a revertant of G29, also took up NH ₄ ⁺ at the same rate as wild type and had fully restored glutamine synthetase activity. Partially restored derivatives, G29R5 and G29R6, grew more slowly than wild type on NH ₄ ⁺ as the nitrogen source, remained derepressed for nitrogenase in the presence of NH ₄ ⁺ , and displayed rates of NH ₄ ⁺ uptake in proportion to their glutamine synthetase activity. Ammonium uptake and glutamine synthetase activity were also restored in R. capsulata G29 exconjugants which had received the plasmid pPS25, containing the R. capsulata glutamine synthetase structural gene. These data suggest that NH ₄ ⁺ transport is tightly coupled to assimilation.Abbreviations used CHES cyclohexylaminoethanesulfonic acid - GS glutamine synthetase - SDS sodium dodecylsulfate     

Non-histone chromatin protein fractions associated with ‘active’ chromatin in embryonic chicken liver

Non-histone chromatin proteins synthesized during chicken embryonic liver development were labeled with [3H]tryptophan and [3H]methionine and characterized by electrophoresis. During embryonic development protein/DNA ratio in chromatin was low (1.30-1.62) but synthesis of non-histone protein was high. Especially one characteristic fraction K (MW 18 000), tightly bound with DNA was preferentially associated with DNAase II sensitive, active transcribed sequences. In 7-day old and adult chicken synthesis of all non-histone proteins was low, fraction K was absent or synthesized only in small amounts in association with non-active sequences, however protein/DNA ratio in chromatin was high (2.30-2.33).     

Exogenous glutathione induces sister chromatid exchanges,clastogenicity and endoreduplication in V79-E Chinese hamster cells

Glutathione (GSH) dissolved in Eagle's MEM and added to cultures o of V79-E cells in concentrations between 2.5 × 10^–4 and 10^–3 moles/l for 1 h induces a dose-dependent cell cycle delay, sister chromatid exchanges and clastogenic damage. 7–8% of the metaphases showed endoreduplication at a recovery phase of 25 and 30 h after treatment with 10^–3 molesll GSH. Higher concentrations were lethal. The highest tolerated dose corresponds to the intracellular GSH level in V79-E cells. In the same range of concentrations, glutathione disulfide was inactive. Endoreduplication induction by GSH is G2-phase specific and endoreduplication metaphases show a reduced occurrence of single SCEs when extrapolated to the diploid complement. The adverse effects of GSH are independent of the presence of serum in the culture fluid but completely abolished when the treatment is performed in Hank's solution instead of MEM. The mechanism of genotoxicity of exogenous GSH is discussed but, at present, no pertinent explanation can be given.Abbreviations BUdR 5-bromodeoxyuridine - GSH glutathione - GSSG glutathione disulfide - SCE sister chromatid exchange     

Extraction and Partial Characterization of Enkephalin-Like Peptides from Splanchnic Nerve

A method is described for the extraction of enkephalin-like peptides from peripheral nerve using chloroform and acidic methanol to facilitate a differential extraction of peptides and lipid. Porcine splanchnic nerve contains enkephalin-like peptides in low amounts compared to porcine adrenal medulla and striatum. Gel filtration chromatography reveals the presence of enkephalin-like peptides in both processed and cryptic forms. This is the first reported isolation and partial characterization of these peptides in splanchnic nerve. The presence of these peptides in this nerve provides support for the contention that the splanchnic nerve can modulate catecholamine release from the adrenal medulla through an effect on opiate receptors located on chromaffin cells.     

Dynamics of orange peel fermentation during ensilage

The dynamics of fermentation during ensilage were studied on orange peel (variety Shamouti) ensiled in 50 plastic containers, 10 kg in each, with an outlet for seepage. At predetermined intervals the containers were weighed and samples were taken from three of them for chemical and microbial analysis. Fermentation losses amounted to up to ca one-third of the fresh peel dry matter (DM) content. Most losses occurred within 10 d of commencement of fermentation, and were attributable to gas release. The major fermentation products were ethanol, lactic and acetic acids (16, 3 and 3% of DM, respectively). The dominant microbial populations were lactobacilli and yeasts. Tests are in progress to inhibit the yeasts and thereby reduce fermentation losses.     

Cytoplasmic suppression of malignancy

Summary Using both normal and transformed rat liver epithelial cells to prepare cytoplasmic hybrids (cybrids) we have found evidence to support the theory that the cytoplasm from a normal cell can suppress tumorigenicity. A unique aspect of this study is that all of the cells utilized, both normal and malignantly transformed, were derived from an original cloned cell. We found that fusing cytoplasts from normal cells to malignantly transformed whole cells resulted in cybrid clones which, when injected into newborn rat pups, isogenic with those from which the cell culture was initiated, yielted tumors in 51% of the animals injected compared to 92% of the animals injected with the tumorigenic parent. Those animals that did develop tumors from the cybrid cells survived longer than those injected with cells from the tumorigenic parent. Thus, the cybrid, formed of cytoplasm from both parents, was less tumorigenic than the malignantly transformed parent cell. When reconstituted cells were prepared by fusing cytoplasts from normal cells with karyoplasts from malignantly transformed cells, a situation in which essentially all of the cytoplasm of the reconstituted cell is derived from normal cells, the tumorigenic phenotype was extinguished. This work was supported in part by United States Public Health Service grant CA12056, and grant CA09100 from the National Cancer Institute, Bethesda, MD. This work is partial fulfillment for the degree of Doctor of Philosophy for B.A.I.     

The phytate and mineral content of some cereals,cereal products,legumes, legume products,snack bars,and nuts available in New Zealand

Analyses for phytate by an indirect precipitation method and for the minerals calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), and manganese (Mn) by atomic absorption spectrophotometry were carried out on 100 foods available in New Zealand. Foods with 1% phytate (dry weight basis) included untoasted muesli, rolled oats, wheat germ, wheat bran, soybean, and some soy products. Most breads contained between 0.35 and 0.60% phytate; legumes on average had 0.62% phytate, as did snack bars. There was a wide variation in Ca and Zn contents: There was a tenfold variation in Ca content among the legume products, whereas there was a seventyfold variation in Zn content among the cereals. The phytate: Zn molar ratio, which is presumed to indicate the biovailability of Zn, was above 20∶1 for two-thirds of the cereals and almost all of the snack bars; it was above 15∶1 for one-third of the breads, almost all of the legumes, and half of the legume products. These high phytate: Zn molar ratios, as well as some Ca: phytate molar ratios above 6∶1, indicate that there might be a reduced biovailability of Zn in many of the foods analyzed in this study.