Selection of Revertants of Kirsten Sarcoma Virus Transformed Nonproducer BALB/3T3 Cells

Revertants of Kirsten sarcoma virus transformed nonproducer BALB/3T3 cells (KA31 cells) were isolated after exposing the transformed cells to 5-fluorodeoxyuridine at high cell density, or when suspended in methylcellulose. Revertants were also isolated by treating KA31 cells with the lectin, concanavalin A, which is manyfold more toxic to transformed cells than for normal cells. The revertants resemble BALB/3T3 cells in their morphology and growth characteristics in that they have a low saturation density, fail to grow in 1% calf serum or when suspended in methylcellulose, and cease to synthesize DNA after reaching their saturation density. Infection by murine leukemia virus rescues Kirsten sarcoma virus from only the concanavalin-A-selected variants, though all the revertants are susceptible to infection by leukemia virus. The concanavalin A revertants also become transformed after infection with murine leukemia virus. All the revertants can be transformed by Kirsten sarcoma virus but not by simian virus 40.     

New aspects of the intrafilamental vascular system in gills of a euryhaline teleost,Tilapia mossambica

Summary The non-respiratory vascular system of T. mossambica gill filaments was studied in serial longitudinal and cross sections. Comparatively few scattered vascular communications occur between the afferent filament artery and the central venous sinus (AVA_aff). The efferent filament artery, however, is connected by regularly arranged anastomoses (AVA_eff), directly, and sometimes indirectly via nutritive vessels, to the central sinus. These AVA_eff are about as numerous as lamellae counted on one side of each filament, although they diminish slightly in number towards the filament base. The relation AVA_eff to AVA_aff was 17.6:1 in the distal and 17.8:1 in the basal filamental region, while in the tip region of 7 filaments 126 AVA_eff but only 1 AVA_aff were encountered. No direct connection between the lamellar lacunae and the central sinus was detected. According to these results, non-respiratory intrafilamental blood shunting appears unlikely. AVA_eff are assumed to be the main route for blood entering the central venous sinus which would consequently flow into the branchial veins.The authors wish to express their sincere thanks to Miss Angelika Krauß for her valuable technical assistance and to Miss Erna Finger for making the photographs. Thanks are also due to Mr. W. Zeltmann for drawing Figs. 2, 5, and 8 and to Mr. K. Herzog for Fig. 7.     

Structural aberrations of the Y chromosome and the corresponding phenotype

Summary the literature dealing with structural aberrations of the Y chromosome and their phenotypic effects is reviewed. A new observation of a patient with Turner's syndrome and the karyotype 45,X/46,X,i(Yp) reported here allows some conclusions on the problem of the localization of sex-determining factors on the Y chromosome. The comparative analysis of all these cases leads to the assumption that the genes for the initiation of testicular development are located on the proximal part of the long arm of the Y chromosome, while the genes responsible for the maturation of the testis are localized on the short arm of the Y chromosome.

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Zusammenfassung Strukturelle Aberrationen des Y-Chromosoms und ihre phänotypischen Auswirkungen werden an Hand der einschlägigen Literatur zusammenfassend diskutiert. Eine eigene Beobachtung eines Turner-Syndroms mit dem Chromosomenbefund 45,X/46,X,i(Yp) erlaubt Aussagen über die Lokalisation von Genen auf dem Y-Chromosom. Auf Grund der Literatur und unseres Falles wird die Annahme gemacht, daß für die Testisanlage zuständige Gene auf dem proximalen Teil des langen Armes des Y-Chromosoms liegen und daß Gene auf dem kurzen Arm des Y-Chromosoms für die Ausreifung der Testes verantwortlich sind.

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Director: Prof. Dr. H.-G. Hillemanns     

The densitometric study of G bands on human metaphase chromosomes

Summary The method of densitometric measurement of G bands on human metaphase chromosomes is described, and some factors influencing the densitometric patterns are discussed. The densitometric patterns are reproducible and typical for a given chromosomal pair, although they display some degree of variability. Typical patterns of all human metaphase chromosomes are presented, with the patterns obtained from the measurement of some structurally abnormal chromosomes (t13q14q, t14q21q, Xp-).

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Zusammenfassung Wir beschreiben die Methode der photometrischen Darstellung von G-Banden an menschlichen Chromosomen und diskutieren über einigen Faktoren, die das Resultat beeinflussen. Die photometrischen Kurven sind reproduzierbar und für jedes Chromosomenpaar typisch. Selbstverständlich muß man mit geringen Abstufungen ihrer Variabilität rechnen. Wir zeigen unsere typischen Kurven aller menschlichen Chromosomen, die mit Hilfe der ASG-Technik gefärbt wurden. Gleichzeitig geben wir einige Kurven abnormaler Chromosomen wieder, die auch in unserem Labordargestellt wurden (t(13q14q), t(14q21q), Xp-).

     

The thermal springs of Bakreswar,India physico-chemical conditions,Flora and Fauna.

The physico-chemical characteristics as well as floristic and faunistic life of the seven thermal springs and one cold spring of Bakreswar, West Bengal form the basis of this paper. A compendium pertaining to the origin, geology and morphometry of these springs has been incorporated in brief.The temperature of the thermal springs remained almost constant over the past two decades and the location of the fissures of the springs is unchanged. On the basis of temperature these thermal springs are grouped into acrothermal and euthermal. The water of all the springs was alkaline with a pH between 7.4 and 9.2 No carbon dioxide was detected during the period of study. Absence of nitrite and traces of nitrate are characteristic features of these springs.The variation of colour of the water may be related to the presence of algal mats at the bottom of the springs. The quantity of plankton was maximal and minimal in thermal springs having highest and lowest temperature respectively. Oscillatoria sp., Navicula sp., Cyclotella sp. and Tetraëdron sp. were noted at temperatures between 26° C and 51° C. It is a new record from India that diatoms like Navicula sp. and Cyclotella sp. can survive in the temperature range of 43–51° C. The thermophilic nematode, Tobrilus sp., Cyclops sp., Nauplius larvae, and Lecane sp. were recorded from Swetganga with a maximum temperature of 44° C. The mechanism of thermophily of the organisms is discussed in brief.     

On the kinetics of erythroid cell differentiation in fetal mice. I. Microspectrophotometric determination of the hemoglobin content in erythroid cells during gestation

In a microspectrophotometric study, photographic emulsions and a computer are used for measuring the hemoglobin content of a large number (about 50,000) of erythroid cells in fetal mice. Histograms of the hemoglobin content in erythroid cells illustrate the kinetics of erythropoiesis in yolk sac derived nucleated cells in the fetal peripheral blood, in fetal liver, and in fetal spleen. After the occasional extrusion of their nucleus, yolk sac derived erythrocytes remain as “macrocytes” in fetal circulation two or three days longer than the nucleated yolk sac derived erythrocytes do. Erythrocytes in fetal liver have a constant hemoglobin content of 28 pg ² until day 17 of gestation. During further erythropoiesis in liver and then in the spleen, this amount is gradually adapted to the normal hemoglobin content in red blood cells of 16 pg.     

The genome sequence of <Emphasis Type="Italic">Enterococcus faecium</Emphasis> 8S3, lactic acid–producing bacterium from Slovak cheese – bryndza with biotechnological potential

New genetic data with biotechnological potential (citrate metabolism, proteases, bacteriocin production) provides the genome sequence of the lactic acid producing bacterium of Enterococcus faecium strain 8S3, isolated from traditional Slovak cheese - bryndza produced from unpasteurised ewe milk. The genome sequence consists of 2.8 Mbp, with a mean G?+?C content of 38.2% and show high similarity to other E. faecium genome sequences. A total of 2.833 coding sequences, including 62 structural RNAs (3 rRNA and 59 tRNA) were predicted. Comparative genomic data indicate that prophages and bacteriophage remnants are the main source of diversity among E. faecium genomes.