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  • 1
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Zoospore mother cells in Bulbochaete are shown to be surrounded by a structure interposed between the plasmalemma and the cell wall which is interpreted as the precursor of the vesicle which temporarily surrounds the zoospore on its release. 2. As this vesicle precursor matures it thickens apically to form a ring consisting of a core and two layers. These two layers envelope the young zoospore as its vesicle. Later a space, referred to as the sub-ring, develops within the middle layer of the ring. 3. Histochemical tests indicate that the vesicle precursor and ring are highly proteinaceous with a small carbohydrate component. 4. Dehiscence is apical and thought to be assisted by the apical ring. Upon release of the zoospore, its vesicle is essentially composed of the inner layer of its precursor.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 86 (1972), S. 265-280 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The ellipsoid to subspherical zoospore of Bulbochaete hiloensis (Nordst.) Tiffany consists of a green body surmounted by a dome-shaped colourless head, around the base of which is a ring of flagella. 2. The body cytoplasm is characterized by a reticulated chloroplast which contains stacked thylakoids; incipient, developing and mature pyrenoids; and microtubules. The remaining cytoplasm contains active ER-Golgi complexes, coated vesicles, dense bodies, cored bodies, a mitochondrial nest, large central nucleus and lipid-like bodies, adjacent to the large vacuoles. 3. The colourless head, packed with mitochondria, has an extensive ER-Golgi system and a mass of vesicles thought to contain mucopolysaccharides. 4. The flagellar apparatus contains approximately forty regularly-spaced basal bodies situated below a banded fibrous ring. Between the basal bodies are located striated ascending roots, microtubular descending roots and supporting structures. 5. Zoospores are positively phototactic and it is suggested that motility is directed either through differential flagellar activity or by an internal steering mechanism affected by reorientation of the flagellar apparatus.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 22 (1974), S. 229-232 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Es wird eine automatische Methode zur Analyse von Metaphase-chromosomen aus Hautfibroblasten und Amnionzellen nach direkter Kultur der Zellen auf Objektträgern mit Hilfe einer im Handel erhältlichen Färbeapparatur beschrieben. Der gleiche Apparat kann auch für die Färbung von Chromosomen anderer Herkunft und für die Färbung von X-Chromatin mit saurem Orcein aus Zellabstrichen benutzt werden. Kurz beschrieben wird eine Trypsinbandenmethode, deren Inkubationszeiten die Anwendung in einem automatischen Programm erlauben.
    Notes: Summary A method is described for the automatic processing of metaphase chromosomes in skin fibroblast and amniotic fluid epithelial cells growing directly on microscope slides using a commercially available staining machine. The same apparatus is used also for the staining of chromosome preparations from all sources and for smears to demonstrate X chromatin using acetic orcein. A brief description of a trypsin banding method with exposure times suitable for incorporation in an automatic programme is also included.
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  • 4
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Direct linear relation exists between the reduced vaporization energy change (ΔH v /RT B ) of benzene and its homologues, C6H5X (X=F, Cl, Br, I) and the X-sensitive dimensionless frequency (hcv/kT B ) at their respective normal boiling point (T B ) temperatures.
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  • 5
    ISSN: 1432-0568
    Keywords: Allantoic placenta ; Blastocyst ; Implantation ; Mesocricetus auratus ; Yolk sac placenta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The processes of attachment, implantation and placentation in the golden hamster (Mesocricetus auratus) have been re-examined. Blastocyst attachment occurs at 4.0 days P.C. and complete interstitial implantation is attained by 5.5 days P.C. At 6.15 days P.C. the trophoblast of the träger breaks into the uterine lumen which becomes filled with blood clot. The advancing träger uses this blood clot as a bridge to reach the decidua basalis, lying on the opposite side of the uterine cavity, at 8.5 days P.C. Thus the uterine lumen becomes obliterated opposite each conceptus by the formation of the allantoic placentas which are vascularised by 8.5 days P.C. Non-glandular extensions of the glandular interlocular lumina penetrate between the decidua capsularis and the muscularis of the antimesometrial wall of the uterus from the 8th day P.C. onwards. On the 14th day P.C. the parietal wall of the yolk sac and its thin covering layer of decidua capsularis disappear to form a completely inverted yolk sac placenta. This places the yolk sac cavity in continuity with the non-glandular extensions of the uterine lumen and re-establishes complete continuity of the uterine lumen.
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  • 6
    ISSN: 1432-0533
    Keywords: Myelin Sheath ; Oligodendroglioma ; Neurilemmoma ; Mucopolysaccharide, Acid ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sulphated acid mucopolysaccharide, probably mainly chondroitin sulphate, has been demonstrated in the cell walls of the tumours of myelin sheath cells. Its function in relation to insulation and impulse conduction is discussed.
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  • 7
    ISSN: 1432-0428
    Keywords: Diabetes in animals ; Chinese hamster ; cricetulus griseus ; inbred strains of mice ; KK mice ; inheritance of diabetes ; diabetes genetics ; polygenic inheritance of diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'hérédité de la glycosurie du hamster chinois est contrôlée par 4 gènes récessifs. Chez l'homozygote, n'importe quelle paire de ces gènes produit la glycosurie. De plus, il y a un certain nombre de gènes :modificateurs: qui contrôlent la sévérité, la durée et la fréquence de la glycosurie. — Chez 18 des 20 souches d'élevages étudiées, les conditions génétiques ont été choisies pour obtenir une manifestation optimale de la glycosurie, ce qui est confirmé par les résultats. Il existe moins d'uniformité dans les 2 autres souches, ce qui suggère que quelques :modificateurs: conservent des propriétés de ségrégation. On postule l'existence de différents génotypes qui devraient permettre de produire des portées d'animaux ayant une proportion de 0%, 50% ou 100% de glycosurie. La transmission de la glycosurie chez la souris KK s'explique par la présence d'un gène dominant ayant une penetrance de 25% et d'un modificateur récessif qui augmente la penetrance à 75%. La confirmation de la présence d'un modificateur récessif chez la souche C57 doit encore attendre la compilation de résultats antérieurs. La glycosurie est avant tout présente chez les animaux mâles et son expression est influencée par des facteurs d'environnement tels que l'élevage et l'agressivité.
    Abstract: Zusammenfassung Die Erblichkeit der Glykosurie des chinesischen Hamsters hängt von 4 rezessiven Genen ab, von denen nur je 2 in homozygoter Form vorzuliegen brauchen, um zu manifester Glucosurie zu führen. Zusätzliche Gene Schemen die Schwere, die Dauer und die Regelmäßigkeit der Glucosurie zu beeinflussen. In 18 von 20 Zuchtlinien wurde versucht, zugunsten optimaler Manifestation zu selektionieren. Die Resultate entsprechen denjenigen die auf Grund der eingangs erwähnten Hypothese erwartet wurden. In den restlichen 2 Zuchtlinien scheinen noch zusätzliche genetische Einflüsse eine Rolle zu spielen. Die Definition von Genotypen basiert auf den erhaltenen Ergebnissen, welche es ermöglichen sollten, Würfe mit 0%, 50% oder 100% glucosurischen Tieren zu erzeugen. — Bei der KK-Maus scheint die Glucosurie auf ein dominantes Gen zurückzuführen zu sein, dessen spontane Penetranz von 25% durch ein rezessives modifizierendes Gen auf 75% gesteigert wird. Die Bestätigung der Existenz des rezessiven Modifikators bedarf noch der endgültigen Auswertung aller Daten. Glucosurie ist hauptsächlich auf männliche Mäuse beschränkt und wird von Umweltsfaktoren wie Aggressivität und Haltung beeinflußt.
    Notes: Summary The inheritance of glucosuria in the chinese hamster is controlled by four recessive genes. Any pair of these genes, when homozygous, will produce glucosuria. In addition to these, there are a number of modifier genes which control the severity, duration, and constancy of the glucosuria. In 18 of the 20 breeding lines reported in this paper the genetic background has been selected for optimum manifestation of glucosuria and the results fit the expectations. In the other two lines there is less uniformity, indicating that some modifiers are still segregating. Genotypes are postulated and it should now be possible to produce litters with 0%, 50%, or 100% glucosurics. — The inheritance of glucosuria in the KK mouse is explained by a dominant gene with 25% penetrance and a recessive modifier which raised the penetrance to 75%. The confirmation of the presence of a recessive modifier in the C57 stock awaits the outcome of backcross data which are presently being compiled. Glucosuria is confined mainly to males, and its expression is affected by environmental factors such as fighting and breeding.
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  • 8
    ISSN: 1432-0827
    Keywords: Cementum ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract A method for the isolation of dental cementum is described. Amino acid analysis of the insoluble matrix of cementum, and chromatography of the CNBr peptides derived therefrom, strongly suggest that this material is mainly collagen with the chain composition α1[(I)]2α2.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 82 (1972), S. 283-299 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The general cytoplasmic features of Fischerella muscicola, Stigonema hormoides and cells of Stigonema mamillosum found as a phycobiont in the lichen Ephebe lanata are similar to those found in other cyanophyte cells. 2. In all instances the outer surface of the quadrilayered cell wall bears a series of ridges. The membrane-like outermost layer (L IV) also exhibits a number of evaginations thought to represent sites of extrusion of material from the cytoplasm through the wall into the enveloping fibrous mucilage. 3. Cross walls are formed by inward growth of the two inner layers of the lateral walls, the daughter cells subsequently moving apart through the inward intrusion of the two outer wall layers and a bulk of mucilage. 4. The daughter cells remain connected by a persistent central region of the original septum. This septum is penetrated by pores, although these do not pierce the underlying plasma membranes and no direct connection of the protoplasts is achieved. 5. An apical cell of S. hormoides was found to be capped by remnants of a cross wall, presumably by the disruption of a previously distal cell.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 90 (1973), S. 343-364 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Sexual reproduction in Bulbochaete hiloensis (Nordst.) Tiffany is mediated by the production of dwarf males and oogonia. 2. Mature dwarf males have a stipe cell and a variable number of antheridia, each divided by a septum separating two spermatozoids. 3. Each spermatozoid consists of a head and body surmounted by a flagellar apparatus with a ring of six to nine flagella. 4. The spermatozoid body is characterized by a large nucleus with chromatin but without an apparent nucleolus, and a highly reduced chloroplast with stroma starch but no pyrenoids. 5. Each spermatozoid is surrounded by a fibrous vesicle and an electron dense layer which are thought to be functional in the sequential release of the spermatozoids from the antheridium. 6. A vegetative photosynthetic cell undergoes division to eventually give rise to an oogonium and primary and secondary suffultory cells. 7. The suffultory cells have highly vacuolate, degenerate cytoplasm with no chloroplast. 8. Within the oogonium, the nucleus becomes located near an extracytoplasmic, fibrogranular mass of mucosubstances laid down in the vicinity of a partial wall discontinuity. These mucosubstances are possibly functional in splitting the wall to form the fertilization pore. 9. The plug progressively disperses as the oogonial cytoplasm rounds off, receding from the cell wall in the apical and basal regions. 10. Following fertilization the oogonial contents refill the enclosing cell wall. The nucleus returns to the centre of the cell and the cytoplasm becomes dominated by numerous closely-packed, lipid-like bodies. Stages in the development of the seven-layered oospore wall are described.
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