Ultrastructure of the oocyte follicles in the crustacean amphipod Orchestia gammarellus (Pallas)]

The follicle cells of the Crustacean Amphipoda Orchestia gammarellus produce syntheses at the level of the ergastoplasm and the Golgi body. No secretary cycle is observed. A complex but permeable network of intercellular spaces provides a path for possible transfollicular penetration for the exogenous fraction of the vitellus.     

Organization of the oocyte nucleus in silphid beetles (Silphidae,Coleoptera-Polyphaga)

Summary In all the Silphid species examined, the oocyte chromosomes were found to, contract to form the karyospheres. Despite this, as the oocytes grow the germinal vesicles increase also very considerably. Production of numerous RNA-containing nucleolus-like bodies was found to be characteristic of the Silphid oogenesis. Experiments with³H-uridine demonstrated that only the karyosphere actively synthesized RNA, while the nucleolus-like bodies remained inactive in this process.This investigation was supported in part under Contract DPKBN/52/76-II. 1.3.10. with the Polish Academy of Science.     

Ultrastructure and biochemistry of the pineal organ in deep-sea lanternfishes (Myctophidae)

Summary Pineal structural and biochemical adaptations in lanternfishes included: 1) few photoreceptor outer segment discs; 2) conventional synapses between photoreceptors and pineal neurons; and 3) low levels (0–60 pg/pineal) of serotonin compared to those (>1.0 ng/pineal) in the goldfish pineal organ. These findings suggest reduced photosensory and/or neuroendocrine functions in these deep-sea fishes.     

Ultrastructure of photoreceptor cells in a vitamin A-deficient moth (Manduca sexta)

Zusammenfassung Die LepidoptereManduca sexta wurde während mehr als 20 Generationen ohne Vitamin A aufgezogen. Feinstrukturelle Veränderungen traten auf: Die Photorezeptorzellen zeigten starke Zunahme und Desorientierung der Mikrovilli des Rhabdoms. Mitochondrien waren aus der Normallage nahe am Ursprung der Mikrovilli gegen die Peripherie der Retinulazelle verschoben. «Zwiebelkörper» (Sammlungen von konzentrisch angeordneten Mikrovillimembranen) und eine grosse Anzahl von Mikrotubuli wurden in den interretinulären Zellen gefunden. Mit Pflanzendiät aufgezogene Insekten hingegen zeigten keine der beschriebenen Ultrastrukturänderungen.     

Ultrastructure and biochemistry of the pineal organ in deep-sea lanternfishes (Myctophidae)

Pineal structural and biochemical adaptations in lanternfishes included: 1) few photoreceptor outer segment discs; 2) conventional synapses between photoreceptors and pineal neurons; and 3) low levels (0-60 pg/pineal) of serotonin compared to those (greater than 1.0 ng/pineal) in the goldfish pineal organ. These findings suggest reduced photosensory and/or neuroendocrine functions in these deep-sea fishes.     

Morphological differentiation of the growing oocyte ofCtenomys torquatus (Rodentia,Octodontidae)

Summary The ultrastructural changes observed during the growth phase of oocytes ofCtenomys torquatus (Rodentia, Octodontidae) are reported. Interest was particularly centered on the transformation and/or distribution of the components of the endoplasmic reticulum. According to the observations made it is suggested that the endoplasmic reticulum stores some kind of material which may support early stages of development.     

Morphological differentiation of the growing oocyte of Ctenomys torquatus (Rodentia, Octodontidae)

The ultrastructural changes observed during the growth phase of oocytes of Ctenomys torquatus (Rodentia, Octodontidae) are reported. Interest was particularly centered on the transformation and/or distribution of the components of the endoplasmic reticulum. According to the observations made it is suggested that the endoplasmic reticulum stores some kind of material which may support early stages of development.     

Ultrastructure of renal collecting tubules following ingestion of a bipyridinium herbicide (Morfamquat)

Zusammenfassung Ratten, denen eine Diät mit niedrigem Gehalt von Morfamquat gefüttert wurde, zeigten nach 6–24 Wochen eine erhöhte Anzahl von Lysosomen in den Epithelzellen der Nierensammelröhren. Im Lumen waren Zelltrümmer zu sehen, die auf eine Zellnekrose im proximalen Nephron schliessen liessen. Die Mitochondrien wiesen weder quantitative noch qualitative Veränderungen auf.

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Acknowledgment. The Morfamquat and recipe of the diet have been generously provided byD. M. Ferguson, Imperial Chemical Industries Ltd., Alderley Park, Nr. Macclesfield, Cheshire, England. The technical assistance of Ms. F. Cohen is gratefully acknowledged.     

Isoforms of soluble alpha-tubulin in oocytes and brain of the frog (genus Rana): changes during oocyte maturation

Rana oocytes have previously been shown to contain much more soluble tubulin than does the brain, suggesting different assembly and disassembly dynamics of frog oocyte tubulin compared to that in brain. By using centrifugation, SDS-PAGE, two-dimensional gel electrophoresis and Western blots, probed with anti-α-tubulin monoclonal antibodies, polymorphic α-tubulins (isoforms) were compared in brains and follicle-enclosed oocytes of northern (Rana pipiens) and southern (R. berlandieri) frogs. Oocyte tubulin in both species had isoforms with greater ranges of isoelectric point (pI) than those of brain tubulins; in particular, the oocyte tubulin pIs ranged further into the acidic region of the isoelectric-focusing gels than corresponding brain tubulin. This difference may, in part, be responsible for the previously reported assembly differences between oocyte tubulin (undetectable assembly) and brain tubulin (high assembly). Isoforms of α-tubulin with relat ively acidic pI were more abundant in northern frog brain and oocyte soluble extracts than in analogous extracts from southern frogs. Furthermore, additional acidic α-tubulin isoforms were found in progesterone-treated oocytes (i.e., eggs), indicating increased heterogeneity of acidic a-tubulin isoforms during oocyte meiotic maturation. Among northern frog oocyte soluble components fractionated on Superose-6b columns, tubulin complexes with apparent molecular mass of about 1800 kDa were found to contain acidic α-tubulin isoforms while the putative oligomeric tubulins with an apparent molecular mass of about 250 kDa contained an additional relatively basic α-tubulin isoform. The acidic α-tubulin isoforms, therefore, are proposed to be associated with cold-adaptable cells of brain and oocytes, and may also be involved in stabilization of large soluble tubulin complexes in oocytes of the northern frog. Received 1 October 2002; accepted 9 October 2002 RID="*" ID="*"Corresponding author.