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
    ISSN: 1573-5176
    Keywords: PSP Toxins ; HPLC analysis ; Alexandrium spp. ; toxic dinoflagellates ; extraction method ; phycotoxins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The optimal conditions were established for extraction of paralytic shellfish toxins from a Danish clone of Alexandrium tamarense using extraction with acetic acid and HCl in the concentration range 0.01–1.0 N. Physical destruction of the cells was investigated microscopically to select the most efficient extraction procedure. The toxin content was quantitated by an automized isocratic reversed-phase high-performance liquid chromatography (HPLC) method. The best results as judged from the total amount of toxins and the toxin profile were obtained using 0.05–1.0 N acetic acid and 0.01–0.02 N HCl. Hydrochloric acid in the concentration range 0.03–1.0 N caused the amount of C1 and C2 toxins to decrease sharply and concomitant increase of gonyautoxins 2 and 3. The phytoplankton extracts with 0.1 to 0.5 N acetic acid or 0.01 N HCl were stable during 6 months at −20 °C, but the extracts with HCl 0.02 N underwent a change in toxin profile, although the total amount of toxins was constant.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1617-4623
    Keywords: Key words Membrane proteins ; Phosphatase regulation ; Pho88p ; Pi transporter ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Transcription of a regulatory gene, PHO81, in the phosphatase regulon of Saccharomyces cerevisiae is repressed by inorganic phosphate (Pi) in the medium via that same regulatory system. The activity of Pho81p, the product of PHO81, is also inhibited by a high concentration of Pi in the medium. Increased dosage of PHO86, a gene encoding a putative membrane protein associated with a Pi transporter complex, activates the Pi-inhibited Pho81p produced under the control of the GAL1 promoter. A new gene, PHO88/ YBR106w, has now been identified as a multicopy suppressor of the rAPase- phenotype of the cells caused by the P i inhibition of Pho81p. The pho86 disruptant expressed rAPase activity in high-Pi medium, while the pho88 disruptant did not. The Δpho86Δpho88 double disruption resulted in enhanced synthesis of rAPase under the high-Pi condition and conferred arsenate resistance on the cells than those in single disruptants of these genes. Its hydropathy profile and the results of an analysis of its cellular localization suggested that Pho88p is a membrane protein similar to Pho86p. Both disruption and high dosage of PHO88 or PHO86 resulted in reduced Pi uptake. These findings suggest that Pho88p is also involved in Pi transport and modulates Pho81p function together with Pho86p.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1617-4623
    Keywords: Membrane proteins ; Phosphatase regulation ; Pho88p ; Pi transporter ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcription of a regulatory gene,PHO81, in the phosphatase regulon ofSaccharomyces cerevisiae is repressed by inorganic phosphate (Pi) in the medium via that same regulatory system. The activity of Pho81p, the product ofPHO81, is also inhibited by a high concentration of Pi in the medium. Increased dosage ofPHO86, a gene encoding a putative membrane protein associated with a Pi transporter complex, activates the Pi-inhibited Pho81p produced under the control of theGAL1 promoter. A new gene,PHO88/YBR106w, has now been identified as a multicopy suppressor of the rAPase− phenotype of the cells caused by theP i inhibition of Pho81p. Thepho86 disruptant expressed rAPase activity in high-Pi medium, while thepho88 disruptant did not. The Δpho86 Δpho88 double disruption resulted in enhanced synthesis of rAPase under the high-Pi condition and conferred arsenate resistance on the cells than those in single disruptants of these genes. Its hydropathy profile and the results of an analysis of its cellular localization suggested that Pho88p is a membrane protein similar to Pho86p. Both disruption and high dosage ofPHO88 orPHO86 resulted in reduced Pi uptake. These findings suggest that Pho88p is also involved in Pi transport and modulates Pho81p function together with Pho86p.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-0972
    Keywords: Endomyces fibuliger ; genetic analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Detailed genetic analysis of Endomyces fibuliger, an amylolytic yeast which is homothallic and exists predominantly in the diploid state, has not been performed. From a naturally occurring strain, E. fibuliger 8014 met, a morphological mutant, 193 met, was obtained by u.v. mutagenesis. To obtain a haploid strain suitable for genetic analysis, an intergeneric hybrid between E. fibuliger 193 met and a strain of a closely related dimorphic heterothallic lipolytic yeast, Yarrowia lipolytica, A his1, was produced by mass mating. The intergeneric hybrid was highly unstable in vegetative culture on yeast extract/phosphate/soluble starch/agar media and produced numerous mitotic sectors. Most of the sectors were mitotically unstable. However, one mitotically stable sector, N14i60 met, was obtained which also differed from the strain 193 as gauged by the appearance of DNA bands on pulsed-field gel electrophoresis. The putative haploid strain, N14i60 met, had six bands whilst the mutant 193 met had seven. Ultra-violet treatment of cells of N14i60 met produced 19 auxotrophic mutants. Protoplast fusion between pairs of different mutants showed complementation and the fusants were unstable mitotically and gave unstable aneuploid and stable haploid sectors of parental and non-parental combinations of markers. It is postulated that complementary diploid fusants, which were obtained by protoplast fusion, produced sectors by mitotic non-disjunction. Such a mechanism provides a means to establish a genetic analysis system for E. fibuliger via the parasexual cycle.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1617-4623
    Keywords: Key words Homeodomain protein ; Mating-type control ; Matα2 ; Disulfide bond ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Matα2 homeodomain protein plays a pivotal role in the control of cell type in Saccharomyces cerevisiae. The homeodomain in the C-terminal region of Matα2 functions as a DNA-binding domain and the N-terminal region, containing two cysteine residues at positions 33 and 34, is thought to be involved in formation of Matα2 homodimers via disulfide bonds. matα2 mutants, isolated in a previous study, in which haploid-specific genes cannot be repressed by the Mata1-Matα2 heterodimer but a-specific genes can be repressed by the Matα2 homodimer, were found to produce mutant Matα2 with a substitution of tyrosine or phenylalanine for Cys33. To clarify the role of Cys33 and Cys34 in the Matα2 protein, we generated several matα2 mutants by site-directed mutagenesis which had serine residues in place of these Cys residues. Transforming MAT a cells with plasmids carrying these matα2 (MATα1 +) mutations rendered transformants unable to mate. Northern blot analysis revealed that transcription of the a-specific gene STE2 and the haploid-specific locus RME1 in these transformants is repressed to the same level as in wild-type MAT a/MATα cells. We concluded that neither Cys33 nor Cys34 is required for repression of a-specific genes by the Matα2 homodimer or of haploid-specific genes by the Mata1-Matα2 heterodimer, and therefore suggest that Matα2 homodimer formation in vivo is not mediated by disulfide linkage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1434-6079
    Keywords: 81.30.-t ; 61.14.-x ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Solid-liquid transition of fine tin particles having diameter of 2–10 nm is studied in-situ by high-resolution transmission electron microscopy under a ultra-high vacuum condition. Melting temperature is confirmed to decrease with the decrease of particle diameter. The particles less than the critical size, 2r c⋍5 nm, are found to have a specific phase between the solid and the liquid phase. The particle in this “pseudo-crystalline” phase contains crystalline embryos in it. Particles larger than the critical size have sharp liquid-solid transition, which completed within the time resolution of our microscope observation, 33 ms upon heating or cooling process. Large solid particles have Wulff's polyhedron, while particles around the critical diameter have rather spherical shape. Structural anomaly at the critical size occurs all over the outer most surface layer slightly below the melting temperature. Origin of the “pseudo-crystalline” phase and surface pre-melting phenomena are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two dominant uninducible mutant alleles in the gal80 locus were identified. The GAL80 s-1 and GAL80 s-2 mutants showed novel phenotypes in response to the newly isolated GAL81-1 mutant allele, a dominant constitutive mutation linked to the gal4 locus; the GAL80 s-1 GAL81-1 strain was inducible and the GAL80 s-2 GAL81-1 strain was uninducible. Many galactose positive revertants from the GAL80 s-2 GAL81-1 strain were isolated. It was proved that each revertant was due to a secondary mutation either in the gal80 or GAL81 locus, whereas revertants due to mutation at the supposed controlling site for the structural gene cluster of the galactose-pathway enzymes have not been isolated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-2048
    Keywords: Cellulose microfibril ; Chlorophyta ; Closterium ; Microtubule arrangement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The microtubule (MT) arrangement in Closterium acerosum cells was observed by indirect immunofluorescence microscopy both during and following cell division, and during cell expansion without cell division. (During the division period, some cells of this alga divide whereas other cells expand in their middle region without division.) Before septum formation, all cells had a ring-like MT bundle (MT ring) in their middle. Both septum formation and expansion without cell division occurred at the position of this ring. During the periods of division, short, hair-like MTs appeared around the nucleus in some of the cells, in addition to the MT ring. In dividing cells, spindle MTs appeared as the chromosomes were condensed. During the early stages of expansion of the semicells, after cell division, the spindle MTs assumed a radial arrangement, moved, and settled in a position between the daughter chloroplasts. These MTs disappeared about 1.5 h after septum formation. As the new semicells were growing, wall MTs appeared, arranged transversely along the expanding wall. These transverse MTs disappeared gradually 4–5 h after septum formation, and only an MT ring remained near the boundary between the new and old semicells. The MT ring was present until the next cell division or expansion without cell division. During the latter course of development, transverse wall MTs were present only at the band-like expanding region. At the earlier stage of expansion without cell division, the short, hair-like MTs remained around the nucleus, but as time passed, both the hair-like MTs and, somewhat later, the transverse ones disappeared and only the MT rings remained. The remaining MT ring was not always positioned at the boundary between the expanding and the old cell region. The temporal relationships between the changes in MT arrangement, and the orientation and localization of cellulose-microfibril deposition are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    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...