Autoradiographic detection of the earliest stage of [3H]-uridine incorporation into the cow embryo

Cow embryos, obtained from superovulated heifers on days 3 and 4 after oestrus, were cultured for 20 min in Ménézo's complete culture medium (B2), enriched with 200 microCi/ml of 5-[3H]-uridine. Semi-thin Epon sections of this material were investigated by autoradiography for sites of RNA synthesis. It was found that 5-[3H]-uridine was incorporated into the nucleoplasm and nucleoli only at the end of the 8-cell stage. This suggested that synthesis of hnRNA and rRNA occurred from this stage onwards. Ultrastructural studies were performed on these embryos as well as on other non-incubated 4-cell embryos recovered on day 2. The transformation of dense fibrillar primary nucleoli into functional reticulated nucleoli appeared sooner in the development of cow embryos than in other mammalian species hitherto studied and took place generally during the 8-cell stage. An unusual step in this transformation was represented by the development of a single vacuole in nucleoli at the beginning of this stage (day 3 post-oestrus).     

Embryonic cholinesterase activity during morphogenesis of the mouse genital tract

Summary In the genital tract of male and female mouse embryos cholinesterase activity is described that is independent from innervation. The enzyme activity is localized in the mesenchyme at the junction of Wolffian and Müllerian ducts with the urogenital sinus. During male development prostate buds and vesicular glands grow out into the cholinesterase-active mesenchyme. During female development the active mesenchyme participates in the downgrowth of the vaginal anlage. Ultrastructurally the cholinesterase activity is localized in the perinuclear cisterna and in smooth endoplasmic reticulum of the mesenchymal cells. The enzyme activity disappears with definitive differentiation of the tissue. The embryonic cholinesterase is a component of a primitive muscarinic system. Its relation to the morphogenetic action of testosterone and its possible general functions are discussed.     

Proacrosin and the differentiation of the spermatozoa

Using the indirect immunofluorescence staining technique, the occurrence and localization of proacrosin, the zymogen form of acrosin, was studied during spermatogenesis in the bull, ram, boar and rabbit. Proacrosin staining was demonstrable for the first time in the early haploid spermatid and increased with the differentiation of the spermatid to spermatozoon. The spermatozoon is covered by a cap-like structure of uniform fluorescence corresponding to the acrosomal compartment of the male gamete. No fluorescence could be found in diploid spermatogenic cells, i.e., in spermatogonia and spermatocytes. An identical developmental pattern of proacrosin was observed with the indirect immunoperoxidase staining technique. However, with this staining technique a distinct distribution of proacrosin staining was observed in the acrosome of epididymal and ejaculated spermatozoa of the bull, ram, boar, rabbit and man. Proacrosin seems to be distributed in the acrosome in granules rather than in the homogeneous form, as was indicated by the results of indirect immunofluorescence staining.     

Pachypteria sinaitica n. sp. - eine aufgewachsene,austernähnliche muschel aus dem unterkarbon Ägyptens

A pseudomonotide pelecypod-Pachypteria sinaitica n. sp. - is described from Abu Durba Formation (Visé) of southwest Sinai. The new species forms a link with rather similar populations in the Lower Carboniferous of Marocco. Like the oysters, but byssate and cemented with its right valve,P. sinaitica n. sp. built up small limestone beds within a marginal marine environment of sedimentation. As regards the isotopie composition, the carbonates of the shell were secreted in a water of approximately 25° C.It follows, that the littoral waters of the southern Tethys were warmer during the Lower Carboniferous than those of present Red Sea.     

Imino proton assignments in the proton nuclear magnetic resonance spectrum of the lambda phage OR3 deoxyribonucleic acid fragment

The 17 base pair duplex d(TATCACCGCAAGGGATAp) . d(TATCCCTTGCGGTGATAp) corresponding to the OR3 operator site of lambda phage has been synthesized and studied by 1H nuclear magnetic resonance spectroscopy at 470 MHz. The 13 imino proton resonances observed at 20 degrees C have been assigned to specific base pairs at positions 3-15 on the basis of nuclear Overhauser effect measurements and studies of the temperature dependence of peak intensities. Resonances from the A-T base pairs at positions 1, 2, 16, and 17 are assumed to be absent from the spectrum because of terminal fraying. Resonance from many of the base pairs suggested by Ohlendorf et al. [Ohlendorf, D. H., Anderson, W. F., Fisher, R. G., Takeda, Y., & Matthews, B. W. (1982) Nature (London) 298, 718-723] to be involved in specific binding of the lambda phage cro repressor are well resolved.     

Chromosomen-Aktivität und biochemische Zelldifferenzierung in den Speicheldrüsen von Camptochironomus

Salivary glands of Camptochironomus tentans and C. pallidivittatus were used to study the question whether genes controlling the synthesis of characteristic cell proteins are located in chromomeres specifically puffed in this tissue. Salivary gland cells produce considerable amounts of secretory proteins. In G. tentans, this secretion was shown by gel electrophoresis to consist essentially of 5 protein subunits. In C. pallidivittatus, a component (no. 6) additional to these was found. Another constituent of the secretion (no. 7) is synthesized in C. pallidivittatus by only a small group of gland cells. — The inheritance of these species- and cellspecific proteins has been investigated by relating their presence in interspecific hybrids to the chromosome constitution. Fraction no. 6 was found to be correlated to a short distal region of chromosome IV in which a tissue-specific Balbiani ring is located. Secretion component no. 7 which is characteristic of the special gland lobe of C. pallidivittatus is also controlled by chromosome IV which in this lobe develops a cell-specific Balbiani ring.

---

---

Herrn Professor Dr. W. Beermann bin ich für die Anregung zu dieser Arbeit, sein stetes, förderndes Interesse und die Überlassung aller Arbeitsmöglichkeiten zu großem Dank verpflichtet. Ferner möchte ich Herrn E. Freiberg für das verständnisvolle Ausführen der Zeichnungen und Herrn Peinmechanikermeister H. Braun für seine vielfältige Hilfe herzlich danken.     

Callus cultures of tomato mutants: I. Nutritional requirements

Callus from hypocotyl, stem, and fruit tissue of tomato mutants was grown on a complex pea extract medium. The genotypes responded differently to the levels of nutrients and stimulators or inhibitors in the medium. Hypocotyl callus of yellow (r) tomato required K(2) SO(4) for quick establishment and continued steady growth for several months; callus of this mutant could also grow with 0.5 % dimethyl sulfoxide in the medium, although growth was less than the control. The red ghost (r(+) gh) mutant is sensitive to a toxic component in the pea extract, and makes its best growth with the standard minerals and vitamins, but in 1/2 concentration pea extract plus 5 % coconut water. Tangerine (t), red lutescent stem (r(+) l(2) ), and r(+) gh are mutants which respond differently to thiourea: t grows about the same at all concentrations, r(+) gh grows best at low thiourea, and r(+) l(2) grows best at the specific level of 20 mg/l thiourea. The recent active t or r(+) l(1) and r(+) l(2) isolates require supplementary auxin to which the older, slow-growing isolates do not respond. However, there is variation in growth response of different isolates of the same mutant. The several red (r(+) ) cultures are similar in their slow growth, but somewhat different in responses to specific nutrients. The recent (+) isolate is one of the most active cultures, in comparison to the slow growth of t callus isolated in 1964. It is therefore concluded that growth is affected both by the specific requirements of the mutant and by the age and vigor of isolates.