Red-breasted goose colonies on the Taimyr Peninsula: Factors responsible for the proximity of goose nests to nests of peregrine falcons,rough-legged buzzards,and snowy owls

Red-breasted goose colonies have been studied near Medusa Bay (73°21′N, 80°32′E), on the northwestern Taimyr Peninsula, and along the Agapa River (70°11′N, 86°15′E) down to its mouth (71°26′N, 89° 13′E), in the central Taimyr Peninsula. Red-breasted geese nesting near peregrine falcons are protected by the falcons from arctic foxes; however, they are sometimes attacked by the falcons themselves. In the colonies near peregrine falcon nests, the vast majority of goose nests were situated no farther than 100 m from the falcon nest. When food is abundant, falcons protect a larger area around their nest. The distance between the falcon nest and the surrounding goose nests is inversely related to the falcon’s activity. In years of higher falcon activity, falcons prevent red-breasted geese from nesting as close to their nest as in years of lower falcon activity. Additional stimuli are required for red-breasted geese to form colonies near rough-legged buzzard nests. The distance between snowy owl nests and red-breasted goose nests was smaller when arctic foxes were abundant than when they were scarce.     

Habitat preference in the critically endangered yellow‐tailed woolly monkey (Lagothrix flavicauda) at La Esperanza,Peru

Habitat loss is one of the main threats to wildlife. Therefore, knowledge of habitat use and preference is essential for the design of conservation strategies and identification of priority sites for the protection of endangered species. The yellow‐tailed woolly monkey (Lagothrix flavicauda Humboldt, 1812), categorized as Critically Endangered on the IUCN Red List, is endemic to montane forests in northern Peru where its habitat is greatly threatened. We assessed how habitat use and preference in L. flavicauda are linked to forest structure and composition. The study took place near La Esperanza, in the Amazonas region, Peru. Our objective was to identify characteristics of habitat most utilized by L. flavicauda to provide information that will be useful for the selection of priority sites for conservation measures. Using presence records collected from May 2013 to February 2014 for one group of L. flavicauda, we classified the study site into three different use zones: low‐use, medium‐use, and high‐use. We assessed forest structure and composition for all use zones using 0.1 ha Gentry vegetation transects. Results show high levels of variation in plant species composition across the three use zones. Plants used as food resources had considerably greater density, dominance, and ecological importance in high‐use zones. High‐use zones presented similar structure to medium‐ and low‐use zones; thus it remains difficult to assess the influence of forest structure on habitat preference. We recommend focusing conservation efforts on areas with a similar floristic composition to the high‐use zones recorded in this study and suggest utilizing key alimentation species for reforestation efforts.     

Characterization of a transferrin-diphtheria toxin conjugate

We report here the synthesis and properties of a hybrid toxin prepared by covalently coupling diphtheria toxin to transferrin. The purified material contained two major hybrid protein species and was highly cytotoxic to mouse LMTK- cells in culture, reducing protein synthesis by 50% in 24 h at a concentration of 1 ng/ml. Cytotoxic activity was completely abolished in the presence of exogenous transferrin or anti-transferrin or anti-diphtheria toxin, thus demonstrating that the hybrid toxin was intoxicating cells via their transferrin receptors and that both the diphtheria toxin and transferrin components of the conjugate were necessary for activity. NH4Cl, a drug that elevates the pH within acidic intracellular vesicles, also blocked cytotoxic activity, suggesting that a low intravesicular pH was required for activity. The inhibitory effect of NH4Cl could be abolished by exposing toxin-treated cells to acidic culture medium, further implicating an acid-dependent step in the mechanism of the hybrid toxin action. Studies on the kinetics of intoxication also implied that endocytosis and exposure to a low pH within vesicles were necessary for cytotoxicity. Altogether, the results suggest that the transferrin-diphtheria toxin conjugate binds to transferrin receptors and is internalized into acidic endocytic vesicles. The enzymatic moiety of diphtheria toxin then apparently enters the cytosol in response to the low pH and subsequently arrests protein synthesis.     

Immunocytochemical detection of triphosphoinositide in vestibular hair cells

Triphosphoinositide (TPI), an aminoglycoside receptor and a possible regulator of cationic permeation through its ability to bind with Ca++, was localized by the protein-A gold technique in vestibular sensory epithelia using an antibody highly specific to TPI. TPI was detected on the stereocilia, kinocilia, and cuticular plate of hair cells, and in the reticular membrane of supporting cells. The cilia of hair cells are damaged by aminoglycosides at a relatively early stage of toxicity. Ca++-regulated bioactivity in this area is probably involved.     

Synthesis of new olean-18(19)-ene derivatives from allobetulin

New olean-18(19)-ene triterpenoids were effectively synthesized by the interaction of allobetulin or its acetate with phosphorous oxychloride in refluxing pyridine. The structures of the synthesized 17-chloromethyloleane-18(19)-enes were confirmed by NMR spectroscopy and X-ray analysis.     

Modulating effect of cerulein on benzodiazepine receptors

Subcutaneous administration of caerulein (100-500 micrograms/kg) significantly reduced the development of picrotoxin (8 mg/kg) seizures in male mice. The same doses of caerulein inhibited 3H-flunitrazepam binding in in vivo experiments. Proglumide, an antagonist of cholecystokinin receptors, in low dose (5 mg/kg) potentiated the effects of caerulein (100 micrograms/kg), whereas the administration of proglumide in high dose (25 mg/kg) reduced the action of caerulein on 3H-flunitrazepam binding and picrotoxin seizures. Caerulein (5-1000 nM) decreased 3H-flunitrazepam binding in in vitro experiments only after supplementation of the binding medium with 120 mM NaCl and 5mM KCl. The results suggest the possible interaction of caerulein with chloride ionophor. It seems probable that the direct interaction of caerulein with chloride ionophor in involved in the inhibitory effect of caerulein on picrotoxin seizures and 3H-flunitrazepam binding.     

Segregation Distortion of Marker Nuclear Genes in Alloplasmic and Isoplasmic Lines of Barley

Inheritance of barley nuclear genes responsible for various morphological marker traits was studied in hybrid populations F₂ and F_a. Nine marker genes showed deviation from Mendelian monogenic inheritance depending on the cross direction and maternal cytoplasm. Segregation biases to both recessive mutant and dominant normal phenotypes were observed. Mechanisms of the segregation bias related to cytoplasm substitution in iso- and alloplasmic lines are discussed.     

The phospholipid-bound fatty acids of fowl and turkey spermatozoa

The composition of the phospholipid-bound fatty acids in the spermatozoa of the turkey, Meleagris gallopavo, and fowl, Gallus domesticus, was studied. The types of fatty acids were similar in the two birds. The ratio of polyunsaturated : saturated fatty acids was generally low but slightly higher in the turkey than in the fowl. The significance of the findings in relation to the origin of the semen collected in these gallinaceous birds and the greater difficulty of freezing turkey spermatozoa was discussed.