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  • 1
    ISSN: 1570-7458
    Keywords: Protein ; diet ; nutrition ; Blattellidae ; cockroach ; development ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nymphal development and adult female reproduction were examined in the German cockroach, Blattella germanica, using a defined artificial diet in which the type of protein was varied. Milk proteins, including casein, supported development poorly compared to meat and plant proteins. Soybean protein supported development better than all other highly purified proteins including vitamin-free casein which is commonly used in artificial diets. Last instar females fed the soybean-based diet eclosed earlier at higher eclosion weights, developed their oocytes at a faster rate and experienced higher fecundity than females fed a vitamin-free casein-based diet. Last instar females exhibited different dose-response patterns on diets containing soybean isolate or vitamin-free casein. However, at all concentrations soybean protein was superior to casein in supporting development. The results of a food utilization study during the last instar revealed that consumption rates varied between females fed the soybean and casein based diets. However, approximate digestibility, efficiency of conversion of digested food and the efficiency of conversion of ingested food did not vary significantly between the two dietary treatments. Differential development of females fed the two diets was attributed to differences in stage-specific consumption rates and the poorer quality of casein as a source of protein for development in this species.
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  • 2
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary 1. Six scientists and technicians were trained in lock-out diving from the submersible “Deep Diver”. 2. A planned program of saturation diving on predetermined sites in depths between 150 and 250 feet (46 and 76 m) was only partially successful because of extreme cold experienced by divers breathing heliox mixtures in 3.5° C water, and because of inadequacies in the submarine handling system. 3. An alternate system of bounce lock-out dives permitted completion of an abbreviated scientific program in depths down to 287 ft (87.5 m). 4. Divers took photographs, rock and sediment core samples, and made collections of common benthic species for subsequent analysis for environmental contaminants. 5. It was effectively proved that diver scientists can train rapidly for lock-out diving programs and perform effective scientific work.
    Notes: Extrait Dans le cadre d'un programme à long terme, subventionné par le “Manned Undersea Science and Technology Office” (MUS&T) de la NOAA en vue de développer les possibilités de travail sousmarin, six savants et techniciens de la biologie marine furent entraînés, à partir du submersible «Deep Diver», à des plongées humides utilisant des mélanges respiratoires d'air, hélium et oxygène. Un programme de plongée saturée à 45–76 mètres, utilisant comme habitacle des plongeurs une chambre de décompression maintenue à une pression correspondant à 45 mètres de hauteur d'eau, n'eut qu'un succès partiel, en raison du froid pénible auquel furent somis les plongeurs dans une eau à 3,5° C et de défectuosités apparues dans l'équipement sousmarin. Un programme alternatif utilisa la plongée rapide, humide et non saturée, la décompression commençant dans le sousmarin et s'achevant dans la chambre de décompression; il permit d'accomplir à peu près tout le programme scientifique prévu. Au cours de 18 plongées fut atteinte la profondeur maximum de 87,5 mètres. Les plongeurs prirent des photographies, récoltèrent des échantillons de roches et de sédiments en vue d'analyser les contaminations par des agents polluants. Il fut démontré qu'un submersible, couplé avec la chambre de décompression adaptée, constitue un équipement susceptible d'aboutir à des observations in situ du fond sousmarin et que des plongeurs de formation scientifique peuvent être rapidement entraînés à effecteur sans danger des plongées humides et à utiliser des techniques de plongée hautement spécialisées.
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  • 3
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The vertical distribution, floristic composition and habitat ecology of sublittoral, benthic algae are described for two deep water, offshore stations in the Gulf of Maine, based on in situ observations and collections to 47 m depth during SCUBA and submarine dives. Twenty species of macroscopic algae were collected between 29 and 45 m. These occurred in two benthic algal associations: a Ptilota serrata association of fleshy, almost exclusively red algae from 29 to 37 m; and a deeper Lithothamnium glaciale association dominated by encrusting corallines and extended from ca 38 m to the lowest limit of macroscopic vegetation at 44 to 45 m. Below 45 m only endozoic and epizoic diatoms associated with sponges were observed. Owing to the seasonal stability, homogeneous composition and clear extinction depths of the two associations, we propose that the extinction depth of benthic seaweeds may provide a useful bioassay for making temporal comparison of water conditions at a single geographic region and, where substrata are similar, spatially among different geographic regions. Data obtained during the Jeffreys Ledge study are discussed in relation to this hypothesis.
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  • 4
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Epidermal cells of normal fin web and of the epidermal papilloma of the flathead sole, Hippoglossoides elassodon, were compared by light and electron microscopy. The predominant cells of normal epidermis are squamous and are characterized by complex microvillous interdigitations between adjacent cells, numerous desmosome-like structures, terminal bars, prominent cytoplasmic filaments, and blunt, broad-based microvilli on the outer (free) surfaces of the superficial cells. The less numerous mucous cells of normal epidermis possess abundant ergastoplasm and mucus-filled vacuoles, but lack desmosome-like structures and cytoplasmic filaments. In contrast, in the epidermal papilloma, mucous cells are absent; and the tumor cells are without microvilli, desmosome-like structures, cytoplasmic filaments, and conspicuous ergastoplasm. The papilloma cells are in addition characterized by certain features not seen in normal epidermis, including prominent nuclear “pores”, very large nucleoli, nuclear dense bodies, vesicular mitochondria with few cristae and dense internal granules, and three types of distinctive cytoplasmic particles of possible viral nature.
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  • 5
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vaginal epithelium of castrate 8.5 week old mice undergoes spontaneous keratinization in the absence of estrogen when placed in hanging-drop organ cultures using chemically defined medium 199. The early stages of in vivo and in vitro keratinization have been shown to be similar and are characterized by marked increases in cytoplasmic ribosomes and filaments which correspond to known biochemical changes induced by estrogen in cells of the female genital tract. Similarly, there are early changes in nuclear chromatin and nucleoli in vitro indicative of active messenger-RNA and ribosomal-RNA synthesis. In the later stages of in vitro keratinization, however, there is, by electron microscopy, a failure of keratohyaline granule formation and incomplete filament aggregation. Thus, estrogen induced in vivo and spontaneous in vitro keratinization are not truly comparable. The changes occurring in the organ culture system used have, however, been shown to be reproducible and, at the light microscopic level, comparable to those previously described in other in vitro studies. The culture vessel used in the present study should offer certain advantages over other organ culture systems.
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  • 6
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 7
    ISSN: 1617-4623
    Keywords: Aromatic acid catabolism ; Escherichia coli C ; Cloned genes ; Pathway organization ; Sequencing hpcR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Homoprotocatechuate (HPC; 3,4-dihydroxyphenylacetate) is catabolized to Krebs cycle intermediates via extradiol (meta-) cleavage and the necessary enzymes are chromosomally encoded in a variety of bacteria. Based on an analysis of the cloned pathway genes, the Escherichia coli C hpc gene cluster was thought to be arranged in two gene blocks transcribed from a central, divergent, operator/promoter region, which was negatively regulated by the Hpc repressor. By a variety of techniques including expression of cloned hpc genes in pUC18/19 vectors, unidirectional deletion subcloning, hybridization studies and nucleotide sequencing it has now been shown that the hpc pathway structural genes are transcribed in one direction. These experiments have also indicated that a decarboxylase and an isomerase of the pathway are encoded by a single gene (hpcE) and have established the exact structural gene order as hpcRphpcECBDGH. The position of the putative regulatory gene, hpcR, is upstream of the first structural gene (hpcE) for the Hpc pathway enzymes. The deduced open reading frame for the Hpc repressor specifies a protein of 148 amino acids with a subunit molecular weight of 17 kDa. The region between hpcR and the first gene for the pathway enzymes has a sequence similar to that for catabolite activator protein (CAP) binding. This region is immediately upstream of a promoter for the pathway structural genes, which has been identified by transcript mapping.
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  • 8
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In 10-day-old Balb/cCrgl mice, the subcutaneous injection of 0.1 μg of estradiol in distilled water per animal per day resulted in the conversion, over a 4 day period, of the original 3 cell layered cuboidal epithelium to a stratified, multilayered, fully keratinized epithelium. By light microscopy, there was development of a prominent stratum germinativum and of a mucinified surface on the 1st day, followed by the sequential formation of a stratum spinosum, a stratum granulosum, and a stratum corneum. By electron microscopy, the principal early modifications consisted of a marked increase in ribosomes, desmosomes, and 70 Å cytoplasmic filaments, the latter being aggregated into approximately 700 Å fibrils. The subsequent establishment of a keratin layer was preceded by the appearance of keratohyaline granules and the disappearance of mitochondria and endoplasmic reticulum in cells immediately above the stratum spinosum and by the development of a transitional cell layer in which there was progressive aggregation of cytoplasmic filaments and disappearance of nuclei, keratohyaline granules, and free ribosomes. In the upper stratum granulosum, transitional cell layer, and stratum corneum there were distinctive modifications in desmosomal structure (composite and modified desmosomes). The morphological and physiological significance of these observations is discussed.
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  • 9
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 228 (1970), S. 153-154 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A useful summary of the history of geological endeavours in New Zealand is provided by Waterhouse2. In particular he pointed out that a Silurian age had, in the past, been wrongly assigned to several of the principal shelly faunas and rock groups of the South Island. For instance, the Haupiri Group ...
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  • 10
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] New stratigraphical and palaeontological data from the Early Palaeozoic Bowers Group of northern Victoria Land indicates that its depositional basin was probably closely linked with the Dundas Trough of western Tasmania. On the basis of these data, a revised reassembly of the Australo-Antarctic ...
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