49 resultados para OB fold
Resumo:
Zur Klaerung der Frage, ob der Begriff "Kinoplasma" fuer gewisse, von MERTON (1924,1926, 1930) beobachtete Bildungen an den reifenden Spermiden von pulmonaten Mollusken oder fuer Bestandteile des Cytoplasmas im Sinne von STRASBURGER und SCARTH zu verwenden ist, werden in der vorliegenden Mitteilung die Vorgaenge bei der Spermiohistogenese von Australorbis glabratus olivaceus untersucht. Es ergibt sich: 1. Das von MERTON bezeichnete "Kinoplasma" existiert nicht als solches, es handelt sich bei den von ihm dargestellten Protoplasmabildungen um kugelige, von den Spermiden abgeschnuerte Restkoerper nicht verwendeten Baumaterials, bestehend aus Protoplasma und einigen Mitochondrien. Sie werden von den Naehr- oder Bazalzellen phagozytiert. Der Ausdruck "Kinoplasma" kann nur fuer die submikroskopischen, geformten, faedigen Elemente des Cytoplasmas reserviert bleiben, die den geradlinigen Fall der uebrigen nicht geformten Komponenten bremst oder ablenkt; damit muss das Kinoplasma aber aus dem Begriff des Cytoplasmas herausgenommen werden, da es, wenn auch vermutlich reversibel, eine Differenzierung darstellt. 2. Der Spermienfaden wird von den Centriolen (Axialfilament) und den Mitochondrien (zwei peripher gelegene Spiralfilamente), sowie einem Plasmamantel gebildet. 3. Nach Beendigung des Auswachsens der Spermiengeissel, die zu diesem Zeitpunkt nur aus dem Achsenfaden und dem Protoplasmazylinder besteht, setzt sich eine Protoplasmamasse vom Kopf in Richtung zum Geisselende in Bewegung. Sie fuehrt den Golgi-Koerper und sehr viele Mitochondrien mit sich. Aus diesen entwickeln sich Fibrillen, die sich zu den beiden Spiralfilamenten zusammenfuegen. Diese Masse entspricht der von MERTON in seiner Theorie als Kinoplasma bezeichneten Komponente. 4. Die Bewegung dieses Protoplasmateils wird auf den Schub zurueckgefuehrt, den die sich bildenden Fibrillen auf die Mitochondrien ausueben. 5. Die Rueckwaertsbewegung dieses Protoplasmakoerpers beruht wahrscheinlich auf Elastizitaet und Kontraktilitaet des Plasmalemmas. 6. Das zum Kopf zurueckgekehrte Protoplasma wird mit restlichen Mitochondrien als Kugel ausgeschieden und von den Naehrzellen phagocytiert. 7. Der Golgi-Koerper wird vor Beendigung der Protoplasmawanderung bereits in der letzten Haelfte der Geissel eliminiert.
Resumo:
A new species of South American lymnaeid snail, Lymnaea rupestris, is described. So far it has been found only in its type-locality, Nova TeuTõnia, a village in the municipality of Seara (27° 07' S, 52° 17' W), state of Santa Catarina, Brazil. It is distinguishable, by characteristics of the shell and internal organs, from the other two lymnaeid species known to occur in the area, Lymnaea columella and L. viatrix. Its shell has 4 markedly shouldered whorls, deep suture, ovoid or rounded aperture occupying about half the length of the shell, and reaches about 6 mm in length in adults; in columella and viatrix the shell has 4-5 rounded whorls, shallow suture, and reaches over 10 mm in adults; the aperture is ovoid, occupying about half the length of the shell in viatrix, about two thirds in columella. Anatomically it is readily separated from L. columella by the shape of the ureter, straight in rupestris, with a double flexure in columella. Comparison with L. viatrix shows the following main differences: distalmost portion of the oviduct with a low, caplike lateral swelling in rupestris, with a well-developed pouch in viatrix; uterus bent abruptly caudalward in rupestris, only slightly curved rightward in viatrix; basal half of the spermathecal duct hidden by the prostate in rupestris, wholly visible or nearly so in viatrix; spermiduct sinuous and uniformly wide in rupestris, straight and gradually narrowing in viatrix; prostate more than half as long and nearly as wide as the nidamental gland, and with a slit-like lumen in cross-section in rupestris, less than half as long as and much narrower than the nidamental gland, and with an inward fold in cross-section in viatrix; penial sheath about as long and as wide as the prepuce in rupesris, shorter and narrower than the prepuce in viatrix. An important ecological characteristic of L. rupestris is its habitat on wet rocks most often outside bodies of water, although in close proximity to them. Specimens were deposited in the following malacological collections: Instituto OswaldoCruz, Rio de Janeiro; Academy of Natural Sciences, Philadelphia; Museum of Zoology, University of Michigan; and British Museum (Natural History).
Resumo:
A description of the species Lymnaea diaphana King, 1830 is presented, on the basis of material collected at its type-locality, San Gregorio, on the north coast of the Strait of Magellan, in the Chilean province of Magallanes. It may be identified by the following characters taken together: adult shell over 10 mm in length, whorls inflated, regularly convex, separated by a well-marked suture, aperture ovate occupying about half the shell length; renal organ forming an approximately right angle with the ureter; pouch of the oviduct well noticeable high on the right ventral surface and on the right side of the nidamental gland; uterus bent to the right into an approximately right angle; body of the spermatheca projected into the pulmonary cavity and adhered to the pericardium and to the roof of the pulmonary cavity; spermiduct highly sinuous, folding dorsalward between the left half of the oviduct and the left shoulder of the nidamental gland, and then winding on ventralward to reach the prostate on the middle line; prostate voluminous, convex on the left, pushed in on the right, with a deep dorsal furrow corresponding to a fold which projects into the prostatic lumen and is more developed at the fore half of the organ; apical end of the penial sheath with about six minute protuberances corresponding to inner chambers; prepuce from about as long about twice as long as the penial sheath, with some variation beyond those limits; lateral teeth of the radula basically tricuspid, with a usually simple ectocone which may show a bifid or trifid point. A diagnosis between lymnaea diaphana and three other lymnaeids which also occur in South America and were previously studied by the author - L. columella, L. viatrix and L. rupestris - is presented.
Resumo:
Graft rejection is the major cause of failure of HLA mismatched bone marrow transplantation because of residual host immunity. we have proposed to use a monoclonal murine antibody specific for the LFA-1 molecule (25-3) to prevent graft failure in HLA mismatched bone marrow transplantation (BMT). The rationale for this approach is three fold: LFA-1 deficient patients (3/3) do not reject HLA mismatched BMT; anti LFA-1 blocka in vitro the induction of T cell responses and T/ non T cytotoxic functions; LFA-1 is not expressed by other cells than leucocytes. We have accordingly treated twenty two patients with inherited diseases and 8 with leikemia. The bone marrow was T cells depled by E rosetting of Campath antibody. The antibody was given at days -3, -1, +1, +3, +5 at dose of .1 mg/kg/d for the first 9 and then .2mg/kg/d from day -3 to +6. Engraftment occured in 23/30 patients as shown by at least HLA typing. Hematological recovery was rapid, GVH was limited. Side effects of antibody infusion included fever and possibly an increased incidence of early bacteral infection (sepsis, 1 death). Immunological reconstitution occured slowly leading in six cases to EBV-induced B cell poliferation (1 death and in two others to transient auto immune hemolytic anemia. There has been only one secondary graft rejection. Sisteen patients are alive 3 to 26 months post transplant with functional grafts. Although the number of patients treated is still low the absence of late rejection so far, gives hope for long term maintenance of the graft using anti LFA-1. Since the antibody is an IgG 1 unable to bind human complement, and since it is known to inhibit phagocytosis, there is a good suggestion that 25-3 act through functional blocking of host T and non T luymphocytes at both induction and effector levels.