ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 2037-2039 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Rapid thermal annealing (RTA) and furnace annealing of Ga-implanted Si were studied. Ga atoms implanted into Si are located on substitutional lattice sites in concentration above the solid solubility limit after short-time and low-temperature annealing. Low-resistivity shallow p+ junctions can be fabricated using this metastable layer. However, precipitation and redistribution of the Ga atoms were observed after high-temperature or longer time annealing. Shallow p+ junctions fabricated by Ga implantation and RTA are suitable for submicron complementary-metal-oxide-semiconductor devices.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 13 (1997), S. 0 
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In vitro fertilization of follicular oocytes harvested from ovaries and matured in vitro was attempted for 55 minke whales (Balaenoptera acutorostrata) captured for Japanese research purposes in the Antarctic Ocean during the period from November 1995 to March 1996. In Experiment 1, effects of culture duration (96 h or 120 h) on maturation of follicular oocytes and addition of caffeine (5 mM) and/or heparin (100 pg/ml) on sperm penetration and pro-nuclear formation were investigated. Spermatozoa recovered from the vasa deferentia of four mature males were diluted (5-fold) and frozen at - 80°C. The post-thawed and pooled spermatozoa were used for in vitro insemination. A higher (P 〈 0.05) proportion of the oocytes cultured for 120 h (34.2% of 260) progressed beyond the second metaphase stage than of the oocytes cultured for 96 h (26.0% of 262). For the matured oocytes, higher rates of penetration (P 〈 0.05) and pronuclear formation (P 〈 0.01) were obtained in the oocytes cultured for 120 h (55.1% and 40.4%) than in those cultured for 96 h (32.4 % and 20.6%). Addition of caffeine and heparin did not show a significant effect. In Experiment 2, follicular oocytes matured for 120 h and then inseminated were cultured to examine the subsequent development in two culture systems (with and without co-cultured cumulus cells). Of 448 inseminated oocytes, cleaved embryos (2–16 cells) were observed with (5.8%) and without (4.9%) co-cultured systems. No cleavage was observed in 54 ova without insemination. These results indicate that in vitro fertilization of minke whale in vitro matured follicular oocytes with cryopreserved spermatozoa is possible, yielding cleaved embryos.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Seasonal variation in reproductive activity in the male southern minke whales was investigated. The animals were killed and collected during the feeding season (December-March) in the Antarctic Ocean in the eastern part of Area III (35°E-70°E, south of 60°S) and Area IV (70°E-130°E, south of 60°S). Blood samples, testes, epididymides, and vasa deferentia were collected from 62 males, which had testes weighing over 400 g each. Changes in testicular morphology and plasma testosterone, estradiol-17β and LH concentrations measured by enzyme immunoassay were investigated. Reduction of testicular function associated with different capture periods was found in the summer season. From December to March, body length and body weight remained steady, but decreases in testicular weight, epididymal weight, and testicular volume were found in February. During the same period, plasma testosterone concentration also declined. A significant decrease in the number of germ cells continued during the period of feeding season. An increase in area of seminiferous tubule tended to proceed in a number of germ cells. These changes reflected the percentage of spermatozoa in the vasa deferentia; in particular, motile spermatozoa were observed in December. Based on morphological observation, spermatogenesis had also declined. These results indicate regulation of testicular function by testosterone, as in terrestrial mammals. A gradual decrease of testicular function occurred during December-January.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 21 (2005), S. 0 
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 45 (1998), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The reproductive form of a macronucleus-specific symbiont Holospora obtuse, when harbored by the macronucleus of the ciliate Paramecium caudatum, selectively synthesized a 63-kDa protein which is immunologically related to GroEL, or HSP60, of Escherichia coli. Heat shock treatment of isolated cells of the reproductive and infectious form of the bacterium also induced the synthesis of the GroEL homolog. Immunoblotting showed that the amount of this protein per cell, whether the reproductive or infectious form, is roughly constant. Cloning and sequencing of a gene coding for the GroEL homolog suggested that the protein is 55.2% identical to GroEL of E. coli at the amino acid sequence level, and that the gene is preceded by an open reading frame which encodes a protein 39.6% identical to GroES of E. coli. Northern blot hybridization showed that the GroEL homologous gene is highly expressed in the reproductive form, but only in a trace amount in the intermediate and infectious form. Immunoelectron microscopy revealed that the GroEL homolog is localized in the cytoplasm of the reproductive and infectious form.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Almost all aphid species (Homoptera, Insecta) have 60–80 huge cells called bacteriocytes, within which are round-shaped bacteria that are designated Buchnera. These bacteria are maternally transmitted to eggs and embryos through host generations, and the mutualism between the host ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 503 (1987), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 51 (2000), S. 265-277 
    ISSN: 1432-1432
    Keywords: Key words: Planthopper — Aphid — Fungus — Symbiosis —Symbiont — Uricase — Uric acid — Yeast-like — PTS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Aphids belonging to the three genera Tuberaphis, Glyphinaphis, and Cerataphis contain extracellular fungal symbionts that resemble endocellular yeast-like symbionts of planthoppers. Whereas the symbiont of planthoppers has a uricase (urate oxidase; EC 1.7.3.3) and recycles uric acid that the host stores, no uric acid was found in Tuberaphis styraci, and its fungal symbiont did not exhibit the uricase activity. However, the fungal symbionts of these aphids, including that of T. styraci, were shown to have putative uricase genes, or pseudogenes, for the uricase. Sequence analysis of these genes revealed that deleterious mutations occurred independently on each lineage of Glyphinaphis and Tuberaphis, while no such mutation was found in the lineage of Cerataphis. These genes were almost identical to those cloned from the symbionts of planthoppers, though the host aphids and planthoppers are phylogenetically distant. To estimate the phylogenetic relationship in detail between the fungal symbionts of aphids and those of planthoppers, a gene tree was constructed based on the sequences of the uricase genes including their flanking regions. As a result, the symbionts of planthoppers and Tuberaphis aphids formed a sister group against those of Glyphinaphis and Cerataphis aphids with high bootstrap confidence levels, which strongly suggests that symbionts have been horizontally transferred from the aphids' lineage to the planthoppers'.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-1432
    Keywords: Key words:Wolbachia—Rickettsiaceae— Bacteriophage WO — Virulence — Ankyrin repeat — Phage evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Wolbachia are obligatory intracellular and maternally inherited bacteria, known to infect many species of arthropod. In this study, we discovered a bacteriophage-like genetic element in Wolbachia, which was tentatively named bacteriophage WO. The phylogenetic tree based on phage WO genes of several Wolbachia strains was not congruent with that based on chromosomal genes of the same strains, suggesting that phage WO was active and horizontally transmitted among various Wolbachia strains. All the strains of Wolbachia used in this study were infected with phage WO. Although the phage genome contained genes of diverse origins, the average G+C content and codon usage of these genes were quite similar to those of a chromosomal gene of Wolbachia. These results raised the possibility that phage WO has been associated with Wolbachia for a very long time, conferring some benefit to its hosts. The evolution and possible roles of phage WO in various reproductive alterations of insects caused by Wolbachia are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 48 (1999), S. 717-722 
    ISSN: 1432-1432
    Keywords: Key words:Buchnera— Pea aphid — Symbiosis — Genomic copy number — Dot-blot analysis — Microscope photon-counting system — Polyploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Although Buchnera, the endosymbiotic bacteria of aphids, are close relatives of Escherichia coli, their genome size is only a seventh that of E. coli. In this study, we estimated the genomic copy number of Buchnera by dot-blot hybridization and fluorimetry using a video-intensified microscope photon-counting system and obtained convincing evidence that each cell of these bacteria contains an average of 120 genomic copies. Thus, the Buchnera symbiont, with many copies of a small-sized genome, is reminiscent of cell organelles such as mitochondria and chloroplasts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...