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  • 1
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    Marine Biological Laboratory (Woods Hole, Mass.) | Arizona Board of Regents
    In:  Viktor Hamburger collection, Box 1, Folder 47, Marine Biological Laboratory Archives
    Publication Date: 2023-01-12
    Description: Letter of recommendation
    Description: Correspondence
    Keywords: People
    Repository Name: Woods Hole Open Access Server
    Language: English
    Type: Text
    Format: image/tiff
    Format: application/pdf
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 8 (1988), S. 39-58 
    ISSN: 0739-4462
    Keywords: proteolytic processing ; yolk enzymes ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Various aspects of the processing of Blattella germanica vitellin (Vt) in the oocyte and egg have been investigated. Employing subunit specific antibodies, the precursor product relationships among the subunits of this Vt have been determined. After endocytosis of Vt by the oocyte, the Mr 160,000 subunit Vt is cleaved to products of Mr 95,000 and Mr 50,000. In association with an unprocessed Mr 102,000 peptide, these form the subunits of the Vt of freshly ovulated eggs. Between 4 and 5 days post ovulation (at 30°C), all three subunits of Vt are again processed proteolytically before use by the embryo. Although Vt's high mannose-type oligosaccharides are trimmed during embryogenesis, their modification occurs subsequent to the day 4-5 proteolysis, precluding the possibility that changes in oligosaccharide content or structure contribute to regulating this second proteolytic event. Although the predominant oligosaccharide of Vt is Man9GlCNAc2, the Mr 50,000 subunit of egg-borne Vt contains a much higher proportion of Man6GlCNAc2 than the other two subunits; therefore, this portion of the precursor vitellogenin must be more accessible to the processing mannosidases of the endoplasmic reticulum during its biosynthesis. A microtechnique for aspirating the yolk from individual eggs in an oothecapermits its isolation free of contamination by embryonic tissue. With this procedure, the specific activity profiles of exo-α-mannosidase, exp-β-N-acetylglucosaminidase, α-glucosidase and acid phosphatase were monitored during the first 6 days after ovulation, and some of their properties were also determined. Expression of the acid phosphatase and exo-β-N-acetyl-glucosaminidase activities coincide with the day 4-5 proteolysis, while α-mannosidase remains relatively constant throughout the first 6 days. Functions for these enzymes and the oligosaccharides of Vt during Vt storage and utilization are proposed.
    Additional Material: 8 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 9 (1988), S. 323-337 
    ISSN: 0739-4462
    Keywords: oocytes ; follicle cells ; vitellogenin ; receptors ; calcium ; calcium ionophore ; calcium chelator ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Two classes of vitellogenin binding sites with Kd-values of 7.3 nM and 290 nM were observed in follicle-membrane preparations of the cockroach Nauphoeta cinerea using a membrane-binding assay at pH 8. Separation of follicle cells and basal laminae from oocyte membranes prior to binding studies showed that the fraction consisting of follicle cells and basal laminae (FC/BL) contained high-affinity binding sites for vitellogenin (Kd=16.6 nM), whereas loweraffinity binding sites (Kd=200 nM) were found in the oocyte membrane fraction. The concentration of Ca2+ had a distinct effect on vitellogenin binding and uptake: maximal binding to the oocyte membrane fraction was observed at 0.3 mM Ca2+ and to the FC/BL fraction at 10 mM, whereas uptake of vitellogenin by oocytes in vitro was highest at 4 mM Ca2+. The calcium ionophore A23187 decreased vitellogenin uptake. This effect of A23187 could be counteracted by the calcium chelator Quin2. A hypothetical model for the uptake of vitellogenin into follicles of Nauphoeta cinerea is suggested.
    Additional Material: 6 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 9 (1988), S. 237-250 
    ISSN: 0739-4462
    Keywords: yolk phosphatase ; α-mannosidase ; Blattella germanica ; proteolytic processing ; vitellin ; embryo development ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Proteolytic processing of the vitellin in Blattella germanica eggs occurs 4 days postovulation and is correlated with both the onset of its utilization and the major portion of the embryo's growth. Yolk phosphatase is also expressed coincident with this event, and some aspects of its activation have been investigated. The enzyme is absent from the ooplasm (yolk) during the first 2 days following ovulation but increases approximately 20-fold in specific activity between days 3 and 4, when assayed at pH 3.9 or 4.8 and 9-fold at pH 6.5. No activation is observed for yolk-bound α-mannosidase, its specific activity remains elevated through the first 6 days following ovulation. This suggests that expression of the phosphatase is regulated independently of that of α-mannosidase in the yolk. Yolk with active phosphatase can dephosphorylate native vitellin, delipidated vitellin, and phosphocasein. Sucrose density gradient centrifugation of yolk obtained from eggs 4 days postovulation, revealed that phosphatase activity cosediments with material which reacts with antivitellin antibodies, while α-mannosidase and β-N-acetyl glucosaminidase are found near the top of the gradient. Oothecae derived from crossing certain translocational heterozygote males and wild-type females contain some eggs with severely depressed levels of yolk phosphatase in which embryos do not grow. Vitellin in these eggs fails to undergo proteolytic processing as late as day 5 postovulation and retains the subunit composition of freshly ovulated vitellin.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 13 (1990), S. 117-125 
    ISSN: 0739-4462
    Keywords: arylphorin ; Trichoplusia ni ; Chelonus ; parasitoid ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Arlyphorin (Ap) is the principal protein of the last larval instar hemolymph of Trichoplusia ni. It was shown to be homologous with the Aps of Manduca sexta and Lymantria dispar by Western blot and quantitative immunoelectrophoresis. Another hemolymph storage protein in T. ni of lesser titer was shown to be homologous with larval hemolymph protein (LSP) of M. sexta. Ap titer increased dramatically in the last larval instar of T. ni, as in other holometabolous insects studied. Parasitization by Chelonus sp. caused the Ap titer to rise prematurely in the penultimate larval instar of T. ni. This rise in Ap in the fourth instar is one of the earliest diagnostic signs of parasitization. Among the suite of behaviors of the Chelonus larva on exiting the host is depletion of the host cadaver of most remaining protein. The T. ni Ap titer in the alimentary tract of Chelonus peaks at that time and declines to zero in the first 24 h after parasitoid emergence, prior to its pupation. Aps are a source of phenolic storage compounds. Hence, premature induction of T. ni is advantageous for the parasitoid's own pupation and adult development.
    Additional Material: 4 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 9 (1988), S. 179-199 
    ISSN: 0739-4462
    Keywords: Blattella germanica ; in vivo endocytosis ; oligosaccharides ; proteolysis ; glycosidases ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The 18S and 33S vitellins (Vts) of Blattella germanica were subjected to periodate oxidation and digestions with α-mannosidase, endo-β-Nacetylglucosaminidase H (endo-H), and trypsin to study their effects on Vt structure and function. Periodate oxidation caused 33S Vt to dissociate to a form that cosedimented with 18S Vt upon glycerol gradient centrifugation but had no effect on the sedimentation of 18S Vt. This result implicates the oligosaccharides in stabilization of the 33S structure. Incubation of 18S and 33S Vts with α-mannosidase and endo-H revealed that the oligosaccharides of both Vts are largely shielded from attack by both glycosidases. However, the carbohydrate of 18S Vt was 3 to 5 times more susceptible to both enzymes, suggesting that the 18S to 33S transition results in decreased accessibility of the oligosaccharides to both glycosidases. Short-term exposure of 18S and 33S Vts to trypsin resulted in limited hydrolysis; the Mr 102,000 subunit of each form was cleaved with an Mr79,000 peptide as a major product. However, the sedimentation properties of the Vts and their relative susceptibilities to α-mannosidase were unchanged; therefore while the Mr102,000 subunit of the Vt is vulnerable to trypsin, it retains its higher-order structure after limited digestion. Endocytosis of radiolabelled 18S Vt by oocytes in vivo decreased about 15-fold after its modification by periodate and sixfold after treatment with α-mannosidase. Limited trypsin digestion also severely diminished its uptake. All injected radioactivity of unmodified 18S and 33S Vts could be recovered from either the hemolymph or ovaries of recipient females. However, modified Vts were taken up from the hemolymph primarily by cells of the pericardium and the fat body, suggesting that these organs participate in a clearance mechanism that recognizes “damaged” Vt molecules.
    Additional Material: 9 Ill.
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  • 7
    Publication Date: 2012-01-01
    Print ISSN: 1360-1385
    Electronic ISSN: 1878-4372
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Cell Press
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  • 8
    Publication Date: 1990-12-01
    Print ISSN: 0012-1606
    Electronic ISSN: 1095-564X
    Topics: Biology
    Published by Elsevier
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  • 9
    Publication Date: 1988-01-01
    Print ISSN: 0739-4462
    Electronic ISSN: 1520-6327
    Topics: Biology
    Published by Wiley
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  • 10
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