In vitro fertilization of mouse and hamster eggs after freezing and thawing

Summary Mouse eggs (12–14%) and hamster eggs (87–94%) appear normal upon thawing after having been stored for 30 min to 25 h at –70°C and –196°C. While 89–98% of the normal appearing hamster eggs are capable of fertilization in vitro, only 4–13% of the mouse eggs can be fertilized. The ability of fertilized eggs to develop in culture and their viability upon transfer to pseudopregnant recipients is under investigation.This work was supported by grants from the U.S. Public Health Service and the Ford Foundation. Sincere thanks are due to Prof.Y. Nishikawa of Kyoto University, Japan, for advice and to Mrs.Rose Bartke and Ms.D. M. Hunt for assistance.     

The viability of pollen grains of a lily (Lilium auratum) and the eggs of the brine-shrimp (Artemia salina) soaked in organic solvents for 10 years

Summary Pollen grains ofLilium auratum which had been stored in n-pentanol, n-butanol and n-propanol for 10 years at –10°C germinated, and the generative nucleus in the pollen tube divided into 2 sperm nuclei. The resting eggs ofArtemia salina soaked in these solvents for 10 years hatched at a high rate.     

Biological studies onPseudohypocera kerteszi (Phoridae,Diptera)

Summary 15 couples ofPseudohypocera kerteszi were introduced into individual tubes containing culture medium, maintained at 22–28°C and 45–55% relative humidity. The courtship and the behaviour of males and females before and after the copula are described for the first time; the number of eggs laid by each female during the oviposition period and the sexual rate in offspring were registered in each tube. The relative viability from egg to imago was determined in 8 of the 15 tubes.This study was made possible by a grant of the State of São Paulo Research Foundation (FAPESP).     

Enzymatic characterization of nine endoparasite species of small ermine moths (Yponomeutidae)

Summary Eight hymenopterous and 1 dipterous species, all endoparasitic in eggs, larvae, or pupae of small ermine moths (Yponomeuta) were investigated for their allozyme variation at 3–29 loci. The mean heterozygosity level of the hymenopterous species is one-third of that of the dipterous species. Zymogram patterns of the parasite larvae do not interfere with those of the host.     

Temperature-dependent activity of mosquito larvicidal factor(s) present inBacillus sphaericus 1593–4 and 1691

Summary The larvicidal factor(s) ofBacillus sphaericus 1593–4 and 1691 was more active at high temperature (33–35 °C) as compared to low temperature (23–25 °C) for the larvae ofCulex fatigans andAnopheles subpictus.     

Effects of the temperature of ice-seeding on survival of frozen-and-thawed mouse morulae

Summary Mouse morulae were frozen to –196°C in the presence of 1.2 M ethylene glycol or 1 M glycerol. After iceseeding in embryo samples at –10°C or below, the survival rates in vitro were lower than those obtained by ice-seeding between –4° and –8°C. The proportion morulae developing into live young in vivo after ice-seeding at –13°C and freezing was lower than that of embryos seeded at –4°C.     

The effect of chronic heat stress on cortisol levels in the antarctic fishPagothenia borchgrevinki

Radioimmunoassay was used to determine levels of the stress-inducible glucocorticoid, cortisol, circulating in the plasma of the extremely stenothermal Antarctic fishPagothenia borchgrevinki at rest and after heat stress. Fish sampled immediately after capture (–1.9°C) had low cortisol levels (10.4±1.4 ng ml^–1, mean±SEM) as did fish which were laboratory rested for 3 days. Sudden exposure to 5°C (48h) resulted in a peak cortisol value after 3 h (69.9±6.8 ng ml^–1) whereas exposure to 8°C (6h) resulted in a peak value after 1 h (73.5±8.0 ng ml^–1). At both temperatures levels remained significantly elevated (p<0.05) for the entire period of exposure. Increased temperature also resulted in a significant change in haemoglobin, haematocrit and mean cell haemoglobin concentration (MCHC) (p<0.05). Plasma lactate was significantly elevated only after exposure to 8°C (p<0.05). Plasma cortisol levels fromP. borchgrevinki are reported here for the first time and show this cryopelagic Antarctic species to have an unusual hormonal stress profile.     

Tip potentials in microelectrodes filled by boiling under reduced pressure

Zusammenfassung Glasmikroelektroden, mit 3M KCl-Lösung gefüllt durch Kochen in Wasserstrahlvakuum, zeigen einen Zentralwert für das Potential an der Elektrodenspitze (tip-potential) von –2,5 mV; 75% geben entsprechende Werte niedriger als –5 mV. Lagerung der Elektroden bei 6°C lässt das «tip-potential» mindestens 2 Wochen unverändert, während bei 22 °C sein Zentralwert nach 3–4 Tagen grösser als –5 mV wird.     

Temperature dependence of neurotransmitter release in the antarctic fishPagothenia borchgrevinki

Summary The quantal contents of endplate potentials from extraocular muscles of an antarctic fishPagothenia borchgrevinki were measured over a range of temperatures. Quantal release was maximal at about 5°C but showed little dependence on temperature between –2°C and 10°C. Above 10°C quantal content declined until release ceased about 18°C. In view of the fact that the ambient temperature at which these fish live is constant at –1.9°C, the results suggest thatPagothenia borchgrevinki is only partially adapted to its environment despite 25 million years acclimatization.The authors wish to thank the staff of New Zealand's Scott Base, Antarctica, without whose cooperation the work would have been impossible. Mr J. Quinn of the Auckland University Physiology Department gave invaluable assistance with computing and electronics and the Antarctic Division of the New Zealand Department of Scientific and Industrial Research provided transportation and logistic support. The project was financially supported by the New Zealand University Grants Committee and the Auckland University Research Committee. S.P. was a Senior Fellow of the N.Z. Medical Research Council.     

Sterilization of solanaceous hadda,Epilachna vigintioctopunctata F. by irradiating pupae using gamma radiation

Summary Sterility in males and females was observed in the resulting adults when 3–4-day-old pupae of solanaceous hadda,Epilachna vigintioctopunctata F. were exposed to gamma radiation doses of 2000 rad and 2500 rad. However, at 2500 rad longevity of treated insects was adversely affected.Acknowledgment. Financial help to one of us (J.K.G.) by C.S.I.R. in the form of J.R.F. is gratefully acknowledged. Authors are thankful to Prof. P.N. Srivastava and Dr A.R. Rao, School of Life Sciences, J.N.U. Delhi for providing radiation facility.     

Effects of low temperatures on survival of frozen-thawed mouse embryos

Summary Almost no damage to mouse morulae was observed between 0 and –40°C, and freezing damage to embryos in DMSO, glycerol or ethylene glycol occurred after exposure to –60, –50 or –50°C, respectively. Cooling embryos in DMSO or glycerol to temperatures below –50 to –60°C increased freezing damage. To the contrary, in the presence of ethylene, glycol, no more damage occurred after exposure to temperatures below –50°C.     

Rice blast,nyctotemperature, and nitrate reductase

Zusammenfassung Der imperfekte PilzPiricularia oryzae (Erreger von Blattflecken und anderen Schädigungen am Reis) befällt anfällige Sorten bei einer Nachttemperatur von 20°C, jedoch nicht bei einer solchen von 30°C. Die Nachttemperatur beeinflusst den Stickstoffhaushalt. Bei 20°C ist die Aktivität der Nitrat-Reduktase in den anfälligen Sorten (Figur, 1–3) wesentlich höher als bei 30°C; die resistenten Sorten (4–7) zeigen keine Unterschiede. Die Bedeutung der erhöhten Enzymaktivität für den Pilzbefall bleibt im einzelnen noch zu untersuchen.     

Resistance of cold-exposed rats to aflatoxin

Summary Male rats kept at a temperature of 4°–5°C were refractory to a lethal dose of aflatoxin compared to animals at 20°–21°C which exhibited a high mortality and marked liver damage. It is suggested that this decreased susceptibility is mediated through a stimulated microsomal drug-metabolizing system in cold environment.     

Die ungewöhnliche Wärmeperiode 1947 statistisch untersucht

Summary In Basle the temperature for the period from April to September, 1947, was 3.4°C above the mean of the years 1826–1946. (The greatest excess in 1826–1946 amounted only to 2.0°C). This number is 4.3 times the standard deviation, a value which, under the postulate of a normal Gaussian distribution, is reached or surpassed with a probability of only 0.0019%. An investigation of the variation of the distribution shows that, indeed, the separate monthly averages give a nearly normal distribution, but that over periods of several months a large negative asymmetry (S) and a positive excess (E) result. It is shown further that the statistical characteristics are fundamentally altered by the mere inclusion of the year 1947. It is proposed that the phenomenon of the hot period of 1947 be studied from all points of view.     

Lack of pituitary involvement in the cold-induced hyperglycemia of the killifish,Fundulus heteroclitus

Zusammenfassung Glukose-Steigerung im Serum vonFundulus heteroclitus nach Akklimatisation an –1,5°C wird nicht durch die Hypophyse verursacht. Hingegen ist die Hypophyse notwendig, um die Serumglukose bei 20°C bei normaler Konzentration zu halten. Hypophysektomie bei 20°C hat eine Abnahme der Serumglukose zur Folge.     

The significance of temperature and barometric pressure changes for the snow surface activity ofIsotoma hiemalis (Collembola)

Summary Temperature is limiting for the snow surface activity ofIsotoma hiemalis: values below a threshold of –2.5° to –3°C are avoided. Changing barometric pressure leads to increased surface activity, thus being responsible for mass appearances. These experiments provide the first evidence for sensitivity to and reaction to barometric pressure changes in insects.The financial support by the Swiss National Science Foundation is highly acknowledged. I thank W. Matthey for the unpublished data onGerris remigis.     

Mixed life cycles in the transitional zone between voltinisms in the fall webworm,Hyphantria cunea

The fall webworm,Hyphantria cunea Drury, was introduced from North America into Japan at half a century ago. At present, the populations north of 36° N are bivoltine and those south of 36° N are trivoltine. In the present study, the life cycle in the transitional zone between voltinisms was clarified in Tsukuba (36.1° N). When fourth instar larvae of the second generation were collected in the field and maintained in the laboratory, the incidence of pupal diapause increased when the sampling date was delayed from 16 August to 5 September. The fact that some developed without diapause inidcates the occurrence of a trivoltine life cycle in this locality, where a bivoltine life cycle is predominant. The critical photoperiod for diapause induction at 20 and 25°C was 14 h 13 min and 14 h 10 min, respectively. The photoperiodic response may explain the rapid increase in diapause incidence in late summer. In laboratory-reared diapause pupae, the time and period of chilling (5°C) greatly influenced the time required for adult emergence at the final incubation temperature of 25°C. However, diapause pupae chilled for a sufficiently long period developed to adulthood rapidly, irrespective of the conditions before chilling. Therefore, the difference in timing of entering diapause between pupae of the second and third generations would not result in their temporal reproductive isolation in the following spring. It is concluded that the mixed voltinism in Tsukuba is not a result of a mixture of genetically distinct bivoltine and trivoltine populations, but a result of the phenotypic plasticity in a genetically rather homogeneous population.     

The effects of temperature on ATPase activity and force generation in skinned muscle fibers from the Pacific blue marlin (Makaira nigricans)

Summary ATPase activity and force generation have been measured simultaneously in isolated, demembranated muscle fibers of the Pacific blue marlin (Makaira nigricans) between 0 and 30°C. Tension generation is relatively independent of temperature above 15°C and falls with a Q₁₀ of <1.5 on decreasing the temperature to 0°C. In contrast, the Q₁₀ for ATPase activity is 2.2 over the range 0–30°C. The results are interpreted in terms of the cross bridge theory of contraction.     

Phenylethanolamine-N-methyl transferase activity in the ground squirrel (Citellus citellus)

Résumé L'activité de la phényléthanolamine-N-méthyltransférase (PNMT) a été mesurée dans l'homogénat des surrénales chez le Spermophile, soit actif, exposé aux températures extérieures de 20–25 °C ou de 6–8 °C, soit réveillé pendant l'hibernation. Chez les animaux actifs, l'effet du PNMT a été le plus faible. Une augmentation significative de l'activité enzymatique a été constatée chez les animaux actifs maintenus à la température de 6–8°C (p<0.001). L'activité du PNMT diminue immédiatement chez les Spermophiles réveillés pendant leur hibernation et ceci par rapport aux animaux actifs maintenus à la même température extérieure (p<0.01).     

Abbau von Quarz mit Brenzkatechin

Summary Fine divided HF-etched quartz was dissolved in a 0.2M solution of pyrocatechol at pH 9.6. Between 17 and 40 °C the dissolution rate (v _s ) follows the equation: logv _s =0.0295 T-20.87 At 25 °Cv _s amounts to 0.8 · 10^–12 g cm^–2 sec^–1. With several phenols the dissolution rate of quartz decreases in the order: pyrocatechol > pyrogallol > 2, 3-dihydroxynaphthalene.