Alterations in plasma-membrane functions after poliovirus infection

After exposure of HeLa cells to poliovirus there is a rapid decline (within minutes) in fluorescence polarization of DPH (1,6-diphenyl-1,3,5-hexatriene). Within one hour after infection the (Na+/K+)ATPase activity of an isolated plasma-membrane-rich fraction is enhanced, the cell volume decreases, and the intracellular concentration of a potent low-molecular-weight inhibitor of host protein synthesis increases.     

Different repetition frequencies of a 120 base-pair DNA-element and its arrangement in Chironomus thummi thummi and Chironomus thummi piger

The repetition frequency of a highly repetitive DNA sequence has been measured in the genomes of Ch. thummi thummi and Ch. th. piger. This sequence is known to be involved in the evolutionary duplication of defined chromosomal segments leading to a significant increase in the genome size of Ch. th. thummi. Reassociation of this highly repetitive DNA sequence which has a repeat length of 120 base-pairs, with total Ch. th. thummi and Ch. th. piger DNA has shown that the repetition frequency in the Ch. th. thummi DNA is 5.5 fold higher than in Ch. th. piger. In both genomes a 120 base-pair sequence is present as tandemly repeated sequence as shown by Southern analysis.     

Zur sozialen Organisation des BienenfressersMerops apiaster

Zusammenfassung Beobachtungen zur sozialen Organisation wurden in einer Bienenfresserkolonie (16 Paare) in Nordost-Griechenland von April bis August 1979 vorgenommen:Die zeitliche Abstimmung der Brutaktivitäten wurde während der einzelnen Stadien des Brutzyklus ermittelt. Die Synchronisation verbesserte sich signifikant zwischen der Fertigstellung der Höhle und dem Beginn der Eiablage.Balzfütterungen und Kopulationen häufen sich wenige Tage vor der Eiablage, werden gegen Ende der Eiablage wieder seltener und treten danach nicht mehr auf.Jedes Paar verteidigt einen Abschnitt der Uferböschung, obwohl es darin nur die Höhle und wenige Sitzplätze benutzt. Territoriale Auseinandersetzungen treten vor allem zwischen angesiedelten Paaren und Neuankömmlingen auf. Obwohl die Angriffe um ein Mehrfaches häufiger von den Territoriumsbesitzern ausgehen, ziehen sich diese später aus einem Teil des Territoriums zurück, und ein neues Paar rückt nach. Diese Streitigkeiten halten nur wenige Tage an.

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On the social organization of the European Bee-eater(Merops apiaster)

Summary Several aspects of the social organization have been studied in a breeding colony (16 pairs) in North-eastern Greece from April until August 1979:Colony synchronization was measured at the beginning and at the end of nest-hole excavation, egg-laying and incubation. The degree of synchrony increased between the end of excavation and the onset of laying.The rates of courtship-feeding and copulation increased a few days before the first egg was layed and decreased again at the end of the laying period.Every pair defended a part of the river bank although it only used the burrow and one or some perches there. Territorial conflicts especially appeared between a settled and an intruding pair. Although the attacks were performed several times more frequently by the territory owners, that pair withdrew from a part of its territory and the other moved up. These territorial conflicts only lasted a few days.

     

Adaptation to different growth temperatures modifies some mammalian cell survival responses

Chinese hamster (HA-1) cells that have been grown at 37 °C since explant several years ago can adapt themselves to grow at temperatures ranging from 32 to 41 °C. This growth adaptation is accompanied by major phenotypic changes in, for exampie, the cellular responses to 43 and 45 °C heat challenges and to ethanol challenges (0–10% in concentration). Cells grown at 39.5 °C are seen to acquire substantial heat resistance when compared with cells grown at 37 °C; resistance is even more pronounced if the growth temperature is at 41 °C. On the other hand, cells grown at 32 °C become more sensitive to heat than controls. Our results also indicate an increased resistance to ethanol of the 41 °C grown cells. By contrast the cells' X-ray survival response is affected only minimally. The changes seen are phenotypic; upon being returned to 37 °C, HA-1 cells within 34 h regain their ‘normal’ heat responses.     

Radiation damage in tripalmitin layers studied by means of infrared spectroscopy and electron microscopy.

Structural deteriorations in biomembranes, as inevitably induced while structural information is gathered by electron optical methods, were evaluated by infrared spectroscopy. Tripalmitin model membranes were irradiated with 100 keV-electrons in an electron microscope. The intensity decay of group vibrations over the dose reveals the sequence of damage in the polar and nonpolar part of the molecule. The C-C backbone, being the most important structural feature, shows a significant latency effect up to 0.6 e-/A2 and is completely disordered by 3 e-/A2, corresponding to about three inelastic processes per molecule.     

Ovarian and adrenal function during the estrous cycle of the sow.

The concentrations of plasma estrogens, progesterone, and corticosteroids and of urinary pregnanediol, pregnanetriol, ketogenic steroids, and corticosteroids were determined as indicators of ovarian and adrenal function throughout a normal sow's estrous cycle. Two broad peaks of plasma estrogen, one lasting 11–12 days during estrus and another 6-day peak period during the early part of the luteal phase were detected. Plasma progesterone was elevated during the late follicular and luteal phase. Two broad peaks of plasma corticoids appeared, one following the decrease of plasma progesterone and the second 7–14 days later. Those elevations in plasma corticoids occurred when estrogen titres were elevated. Urinary determinations generally reflected plasma findings. Estrogen levels began to rise during the follicular phase while a reasonably high progesterone level was evident. Estrogen titres never decreased to non-detectable levels. An interrelationship between adrenal function and ovarian estrogen production is suggested.     

Sex-related differences in food and water intake and body weight changes with prolonged administration of adrenaline in the rat

Male and female rats were treated with different high doses of adrenaline for five days. Their food and water intakes and body weights were recorded. A considerable sex-difference was found on the 5th day in body weights and plasma glucose concentrations. Males had higher plasma glucose and lost more weight than females. Females ate and drank more than males throughout the experiment. The adrenaline-sensitivity of females decreased by the third day but it did not change in males. These data suggest that females are able to activate mechanisms that compensate the effects of high adrenaline levels while males are not, or their compensatory mechanisms are less efficient.