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 effects of time of equilibration with cryoprotectants at 0°C prior to freezing on the survival of mouse embryos frozen by the two-step method

Summary Mouse embryos were frozen by the two-step method after equilibration for 0.1–60 min with cryoprotectants at 0°C. No survival or a very low survival was obtained after equilibration for only 0.1 min. The morulae showed the highest survival rates when equilibration time was 5–30 min with 2 M DMSO, 20–30 min with 2 M glycerol, 5–10 min with 2 M ethylene glycol and 20–30 min with 2 M propylene glycol, respectively.     

The effects of time of equilibration with cryoprotectants at 0 degree C prior to freezing on the survival of mouse embryos frozen by the two-step method

Mouse embryos were frozen by the two-step method after equilibration for 0.1-60 min with cryoprotectants at 0 degree C. No survival or a very low survival was obtained after equilibration for only 0.1 min. The morulae showed the highest survival rates when equilibration time was 5-30 min with 2 M DMSO, 20-30 min with 2 M glycerol, 5-10 min with 2 M ethylene glycol and 20-30 min with 2 M propylene glycol, respectively.     

Survival of rabbit embryos after rapid freezing and thawing

Summary Frozen storage of rabbit embryos at the 16-cell stage in 2.0 M dimethylsulfoxide (DMSO) in phosphate-buffered saline (PBS) was achieved by a 2-step procedure. After storage for 10 days at–196°C they were revived by rapidly thawing at 500°C/min. On transfer of these embryos to pseudopregnant foster mothers, 50% survived to term. The difference in in vivo survival between frozen-thawed and frozen-thawed-cultured embryos was not significant.Acknowledgment. The authors thank the Director for the facilities. VHR is supported by Council of Scientific and Industrial Research (India).     

Freezing and transplantation of brain tissue in rats

Summary Neocortical tissue obtained from rat embryos was frozen and stored at –70°C for 6 h prior to transplantation into the cerebellum of neonatal rats. Growth, differentiation, and integration of this tissue within the host brain was comparable to that obtained from freshly dissected and transplanted tissue. It is suggested that freezing to low temperatures does not adversely effect the viability or transplantability of the neural tissue.Supported by N.I.H. research grants Nos NS-08817 and CA-14650.     

Antifreeze agents in the body fluid of winter active insects and spiders

Summary Insects and spiders which are active at subzero temperatures on snow in winter are found to be protected against internal freezing by antifreeze agents present in their body fluid. The body fluid has a melting point of about –1 °C, but the antifreeze agents prevent growth of ice crystals at temperatures down to –6 to –7 °C.Acknowledgment. We would like to thank Anne Lohrman for her kind help in collecting insects and spiders.     

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.     

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.     

Veränderungen der thermoelastischen Kontraktion von Haut und Nerv bei alternden Tieren

Summary The thermo-elastic contraction which has been found to increase with age in the tendons, has been studied in the skin. This shows a contraction between 64–66°C similar to that of tendon fibres. In 22 month old rats, it reaches 5–6 times greater values than in 3 month old animals. The skin also shows a second contraction between 67 and 70°C. After the ninth month, in a continuously increasing degree, a third and fourth step of contraction appear at higher temperatures (up to 82°C).The sciatic nerve also shows a thermo-elastic contraction after the fourth month at 76–80°C. This increases with age, and, as in the case with the skin, several more steps of contraction appear at higher temperatures, up to 92°C. It is improbable that these thermo-elastic contractions are related to «elastin». The changes with increasing age, however, show a similarity to the age changes of «elastin» in so far as the thermic contractility increases with age.     

Effect of water temperature on the motility ofPelagia noctiluca (Forksal)

Summary Laboratory tests have been performed, on the behavior of the jellyfishPelagia noctiluca as a function of the water temperature. It has been found that the usual contractions of the umbrella are almost completely missing at 6°C; they begin to appear at about 7–8°C and they reach frequencies of about 10 and 40 per min at 11 and 15°C respectively. An ambient temperature of about 11°C appears to be a threshold value below which this kind of medusa ceases to move actively and sinks, while at higher temperatures it gradually begins to shift, showing a positive thermotropism in the presence of temperature gradients greater than about 0.01 °C/cm.This work was supported by grant No. 80.00748.88 from the National Research Coucil of Italy (CNR).     

Induction of zygospores at high temperatures in the thermophilic,speciesMucor miehei with aspartic acid and phenylalanine

Summary The importance of amino acids in the induction of zygospores in mucors has been realized for the first time. It was found that in the thermophilic, speciesMucor miehei zygospores at high temperatures (40–50°C), can be induced by addition of phenylalanine and aspartic acid.     

Glycerin prevents the ‘heat-death’ of ehrlich ascites tumor cells

Summary When heated to 45°C for 20 min Ehrlich ascites tumor and NK-lymphoma cells are irreversibly damaged, so that they lose transplantability. The presence of 7–8% glycerol during heat treatment protects EAT cells completely and NK-lymphoma cells partly against this injury.     

The effects on thermoregulation of intracerebroventricular injections of L-aspartic acid in the sheep

Summary L-Aspartic acid was injected into a lateral cerebral ventricle of the sheep at ambient temperatures between 0° and 40°C. Doses of 100 or 500 nmoles·kg^–1 caused a rise in heat production and/or a decrease in heat loss; rectal temperature rose. Atropine sulphate attenuated or prevented these effects.     

Aufhebung der Thermothyrin-A-Sekretion der Schilddrüse durch Fütterung mit Methylthiouracil

Summary G. Mansfeld demonstrated that in the serum of overheated animals a substance (thermothyrine A) is present which, injected into normal animals, decreases O₂-consumption. Serum of thyroidectomized animals has no effect.Dogs and rabbits were treated daily with 0.10 g per kg methylthiouracil during 4 weeks, and were than subjected for 5 hours to a temperature of 34–35° C which raised their body temperature by 0.5–1.5° C. 2.5 cm³ of serum obtained at the end of the 5 hours period failed to reduce O₂-consumption of normal rats, while sera of untreated dogs and rabbits produced after similar exposure to high temperature a fall of O₂-consumption by 14–48%. It is therefore evident that methylthiouracil not only inhibits the formation of thyroxine but of thermothyrine A as well.The fact that thermothyrine A contains no iodine proves conclusively that the action of thiouracil compounds cannot be exclusively an inhibition of iodinization.     

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.     

Heat shock enhances thermotolerance of infective juvenile insect-parasitic nematodesHeterorhabditis bacteriophora (Rhabditida: Heterorhabditidae)

Insect-parasitic nematodes possess many of the attributes of ideal biological control agents, but intolerance to extreme temperatures can restrict their use. We examined whether heat-shock treatments could improve nematode survival and infectivity at temperatures that normally inhibit their activity (35 and 40°C). Nematodes exposed to a sub-lethal temperature (35°C) for 3 h with a latency period of 1–2 h at 25°C killed insects at 35 and 40°C. Correlative evidence was obtained between increased thermotolerance and the synthesis of 70-kDa heat-shock proteins (hsps). These results provide the first evidence of hsp synthesis in the development of thermotolerance and biological activity in the non-feeding, developmentally arrested, infective juvenile nematodes.     

Developmental patterns of supercooling capacity in a subantarctic wingless fly

Anatalanta aptera is a wingless fly which lives in subantarctic islands, particularly in sea bird colonies. Developmental patterns of supercooling capacity were studied in an experimental population reared at 5°C and fed ad libitum. Mean supercooling points of the eggs, second and third instar larvae, pupae, teneral and mature adults were –28.0°C, –10.8°C, –8.8°C, 17.6°C, –16.6°C and –8.2°C respectively. Low mean supercooling points were found for inactive stages (eggs, pupae) and, unexpectedly among Diptera, teneral adults. Mature adults had a combination of low supercooling ability, high lipid content and physogastry. The results are compared with those obtained in winged species from other families of Diptera.     

Kälte als Auslöser einer Glykogen-Speicherung während der Oogenese vonMusca domestica

Summary InMusca domestica reared under standard conditions (21 °C), glycogen is stored in the oocyte towards the end of egg development. By 1–3 days exposure to lower temperatures (4 °C), a glycogen deposition can be released already in young follicles. This premature glycogen synthesis is not restricted to the ooplasm. Carbohydrates are also found in the nurse cells and the follicle epithelium. Similar results were formerly obtained by inhibition of oogenetic protein synthesis.

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Herrn Prof. Dr. Dr. h.c.Bernhard Rensch zum 70. Geburtstag gewidmet.     

Der Typus der Polymerisation des flüssigen Vinylchlorids

Summary Pure liquid vinyl chloride cannot be made to polymerize through heating it up to 110°. In the presence of benzoylperoxide on the contrary polymeres with large molecules are formed by rapid reactions already at low temperatures (20°–50°). In this respect vinyl chloride distinguishes itself from the aromatically substituted ethylenes, which polymerize not only in the presence of peroxide but also in consequence of a purely thermal stimulus.     

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.