37 research outputs found

    Terrestrische und semiterrestrische Ă–kosysteme

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    Spring food habits of Wolverine (Gulo gulo) in the Colville River watershed, Alaska

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    Wolverines (Gulo gulo) are relatively abundant on the North Slope of Alaska, an Arctic ecosystem dominated by tundra habitats that run north from the Brooks Range across a wide coastal plain to the Beaufort Sea. The region contains a range of potential Wolverine prey species, including ungulates (Caribou [Rangifer tarandus], Moose [Alces americanus]), Arctic Ground Squirrel (Urocitellus parryii), and both Soricidae and Cricetidae species. The seasonal composition of these, and other prey species, in the Wolverines’ diet is not well understood. We collected Wolverine scats during spring (March–May) on the North Slope while tracking animals from snowmobiles and with helicopters that visited areas identified as of interest during ground surveys or using global positioning system collared animals. We analyzed prey remains in 48 scat samples based on hair, bone, and other prey fragments. We then calculated frequency of occurrence, percentage of occurrence, and weighted percent volume for each major prey category detected. We confirmed species identity of scats as Wolverine by amplifying the control region of the mitochondrial DNA. We estimated spring diet diversity and richness based on nine major prey categories detected in scats. Ungulates and cricetids together constituted 69% of the Wolverines’ spring diet, with Snowshoe Hare (Lepus americanus) constituting 9%, fox (Vulpes spp.) 6%, Arctic Ground Squirrel 2%, birds 2%, American Beaver (Castor canadensis) less than 1%, and unknown 6%

    Urban-induced changes in tree leaf litter accelerate decomposition

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    GENETIC-ANALYSIS OF THE PHOSPHINOTHRICIN-TRIPEPTIDE BIOSYNTHETIC-PATHWAY OF STREPTOMYCES-VIRIDOCHROMOGENES TU494

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    ALIJAH R, DORENDORF J, TALAY S, PĂĽhler A, WOHLLEBEN W. GENETIC-ANALYSIS OF THE PHOSPHINOTHRICIN-TRIPEPTIDE BIOSYNTHETIC-PATHWAY OF STREPTOMYCES-VIRIDOCHROMOGENES TU494. APPLIED MICROBIOLOGY AND BIOTECHNOLOGY. 1991;34(6):749-755.Streptomyces viridochromogenes Tu494 produces the antibiotic phosphinothricyl-alanyl-alanine (Ptt). Ptt-non-producing mutants were isolated following N-methyl-N(t)-nitro-N-nitrosoguanidine (NTG) or UV light treatment of spore suspensions. In co-synthesis and bioconversion experiments the mutational blocks in the biosynthetic pathway were localized. The mutant NTG1 was analysed in detail. This mutant acts as a secretor for all other mutants. From bioconversion experiments with presumptive precursors circumstantial evidence was obtained that NTG1 is mutated in a gene involved in the alanylation of N-acetyl-demethyl-phosphinothricin. Using a cosmid gene library the DNA region complementing the defective gene of mutant NTG1 was isolated on a 4-kb BamHI fragment. Subcloning experiments showed that a 3-kb BglII/BamHI fragment is sufficient for complementation of mutant NTG1

    Zur Photochemie in Alkalihalogenidkristallen

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    Theory of Color Centers, II On the Nature of V 3

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