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
Filter
  • Cell & Developmental Biology  (21)
  • Life and Medical Sciences  (21)
  • ASTROPHYSICS
  • GEOPHYSICS
  • Humans
  • Lunar and Planetary Science and Exploration
  • 2015-2019
  • 1985-1989
  • 1930-1934  (21)
  • 1934  (12)
  • 1933  (9)
Collection
Keywords
Publisher
Years
  • 2015-2019
  • 1985-1989
  • 1930-1934  (21)
Year
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 54 (1933), S. 477-491 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mitochondria in the male germ cells of Sciara exhibit peculiarities as regards both morphological characteristics and distribution. In form. they show superficial similarity with those of some of the scorpions, while their distribution may be peculiar to the genus and depend on unusual meiotic divisions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1933), S. 207-251 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Goodeidae are a family of cyprinodonts containing about nine genera and twenty-six species. They are confined exclusively to the Mexican Plateau and to streams in the immediate vicinity. All are viviparous. Fertilization is internal. The eggs are extremely small and contain very little yolk. The embryos are retained in the ovarian follicles until the yolk is practically absorbed, in the meantime developing unique absorptive organs in the form of extensive ribbon-shaped proctodaeal processes. The embryos are evacuated into the intra-ovarian cavity where they are retained for several weeks, during which time the proctodaeal processes become extended. The ovary becomes a nutritive organ and produces secretions which are discharged into the intra-ovarian cavity and absorbed by the embryo through their unique processes. The processes differ in form, number, and histological structure, but are specific in their peculiarities for each species. These specific differences, together with marked differences in the ovary, will furnish a basis for a re-classification of the genera and species of the family. A comparison in made between this family and the other ovo-viviparous and viviparous cyprinodonts, on the basis of which it is concluded that the Goodeidae have arisen separately from an ovo-viviparous ancestor, which in turn was derived from an ovo-viviparous type. A comparison is also made between the peculiarities of reproduction in this family and those of other viviparous teleosts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 325-337 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The purpose of this study was to learn something of the nature of the bead-like bodies which occur in the head of the sperm of the fowl since it was found in a previous study that they are apparently affected in a characteristic manner by vitamin E deficiency.Staining tests indicate that these bodies are composed of fats and fatty acids since they respond to osmic acid and Nile blue sulphate. They are also impregnated with silver nitrate and hence may be associated with the so-called Golgi materials of the cell.The beads first appear as a complete single row but subsequently they undergo fragmentation and redistribution. The whole process is probably a final transitory step in sperm transformation.The presence of this fatty material may signify that the sperm of the fowl, in contrast to that of most other animals, carries a store of food material to support its activity after liberation. The sperm may also be the carrier of a definite amount of vitamin E. Furthermore, the presence of this material may offer an explanation of the high resistance of the testis of the fowl to vitamin E deficiency because, since this vitamin is fat soluble, the testis as a whole would probably receive a disproportionately large share of the vitamin E stores of the individual.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934), S. 577-609 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An investigation has been conducted to ascertain the relationship of certain structures in the embryo of the grasshopper known as Melanoplus differentialis with reproductive organs in the adult male.The order of development of these structures was traced through the entire life history.It was determined that they are the rudiments of certain reproductive organs and that the knowledge obtained serves as an aid in more accurately classifying insects.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histological studies of testes of both immature and mature individuals show that the peritoneal epithelium does not give up its proliferative capacities with the completion of testis differentiation. Certain regions of the antimesorchial surface retain their activity and continue to contribute cellular elements during testis growth. Stromal cells, germ cells, and sections of or entire seminiferous tubules originate from the peritoneum in the form of cord-like ingrowths. In this form, the proliferations of the germinal epithelium of the testes are similar to and homologous with the continuous proliferations of the germinal epithelium of the ovary.In Sternotherus, both testis and ovary differentiate out of a bisexual primordium in which the deeper parts of the germinal epithelium form an ovarian cortex. Since the germinal epithelium persists as an active part of both ovary and testis, it must be responsive to the same physiological factors of female or male differentiation respectively. It is indifferent sexually and once the direction of sex differentiation is established, the response of the germinal epithelium is in the determined direction. Its activity is then to produce either seminiferous tubules or ovarian follicles, and is directly dependent upon the processes of embryonic sex differentiation and determination.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 339-359 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of vitamin E deficiency in the fowl were observed in Rhode Island Red males over a period of approximately 2 years.Mating experiments showed that after 1 year on the E-free diet all of the males were capable of fertilizing ova, but that after 2 years some of the males were sterile.Sperm smears showed that shortly after the beginning of the experiment, many of the mature spermatozoa exhibited an abnormal condition of the nuclear material of the head, while others remained normal.In histological sections of the testes made at the end of the 2 years, conditions varied from almost normal to complete atrophy, the latter being a condition that has already been described in the male mammal. Moreover, the conditions in any given section were not uniform for even in an advanced stage of E deficiency there were small islands of apparently normal tissue. However, in this case, as in the mammal, the process of degeneration affects the mature sperm cells first and gradually works to the outside of the seminiferous tubule thus attacking the youngest maturation stages last.The results of the experiment point definitely to destruction of the testis under prolonged E-deficient conditions but it is also quite apparent that the testis of the fowl is extremely resistant to vitamin E deficiency.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 54 (1933), S. 521-547 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The sex cycles of a chimpanzee were studied for 18 months, during which the animal matured, menstruated four times, conceived, and delivered.Pronounced swelling of the ano-genital region appeared periodically prior to the first menstruation. During menstrual cycles the swelling endured during most of the period between flows. Genital swelling was always accompanied by estrus; copulation and insemination never occurred during its absence.The animal was alert and active when in estrus, demonstrated non-sexual affection for the male just prior to the flow, and appeared to be physically distressed during the first days of each flow.There were periodic weight changes coordinated with the animal's menstrual cycles.During pregnancy menstruation ceased, but genital swelling, with accompanying sexual receptivity, continued in irregular cycles.Cyclic changes in the desquamation of the vaginal epithelium occurred during menstrual cycles, were absent during pregnancy.The gestation period was approximately 246 days. At death from puerperal sepsis, 15 days after delivery, the ovaries were in a restin stage, one of them bearing a degenerating corpus luteum.The evidence given indicates that sex-skin swelling and estrus are similarly controlled, but may occur independently of menstruation, cornification of the vaginal epithelium, or ovulation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Basophiilic granule cells which occur in vast number in the connective tissue throughout all regions of the alimentary canal of sockeye salmon and speckled trout are interpreted as histogenous mast cells. Their occurrence in several other species is noted. None could be found in blood or in any other organs. Their development from mesenchymal cells is described (speckled trout). Their function or possible relationship to functional conditions of the tract could not be determined. Experiments showed the granules to be quickly destroyed by acids and bases but not by water in the fresh condition, but they were extremely stable structures after Helly fixation. In living cells, the granules are probably fluid, and consist of proteins. There was no indication of the granules being composed of mucin, or of the cells being degenerated forms. The granules are basophilic at all times.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 577-591 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nuclear band of the cells of the salivary glands of Chironomus larvae regularly consists of four segments or chromosomes. Each of these may be recognized by its characteristic distribution of chromatin discs of various sizes. When nucleolar elements are present they have a definite location in relation to the chromation discs of a certain chromosome. The diploid number of chromosomes is eight; therefore, the four segments in the cells of the salivary glands represent four pairs of homologous chromosomes in somatic synapsis which here is not a simple approximation but an accurate pairing part by part of the homologous chromosomes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 593-601 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The rate of maturation and of development during the first 4 days has been followed in Melanoplus differentialis eggs (from mated females) collected (1) just before they were laid, or (2) immediately after oviposition had been completed and (1) either fixed at once, or (2) after incubation at 25°C. for definite periods.
    Additional Material: 1 Ill.
    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...