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.     

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.     

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.     

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.     

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.     

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.     

Role of calcium in the histamine release induced by D-galactosamine from rat mast cells

Summary Rat peritoneal mast cells were isolated and purified by differential centrifugation in Ficoll. Cells pooled from three to four rats were suspended at approximately 10⁶ cells/ml in a buffered salt solution and incubated for 1 h at 37°C in 300 l volumes in the absence or presence (9×10^–4 M) of calcium chloride. Addition of D-galactosamine hydrochloride (DGM; 2.8×10^–4 M) caused (in addition to basal release) a mean ±SEM percent histamine release of 15.7±5.2 in the presence of Ca⁺⁺ and 19±4.9 in the absence of Ca⁺⁺ (p>0.05). It is suggested that D-galactosamine does not require extracellular Ca⁺⁺ for the release of histamine from the rat mast cell.A preliminary analysis of these results was presented at the International Symposium on calcium entry blockers and tissue protection, Rome, 15–16 March 1984.     

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).     

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.     

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.     

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.     

Ion-solvent interaction from viscosity,apparent molar volume and conductivity data of bromates,iodates and sulphates of potassium and sodium in dioxane-water mixtures at different temperatures

Summary The viscosity, apparent molar volume and conductivity of KBrO₃, NaBrO₃, KIO₃, NaIO₃, K₂SO₄ and Na₂SO₄ at mass fraction of dioxane (10, 20 and 30%) — water mixtures at 30–45°C±0.01°C have been measured. The ions appear to interact and the ion-solvent interaction is of the order BrO ₃ ^– >IO ₃ ^– >SO ₄ ^2– .     

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.     

Ein Beitrag zur irreversiblen Temperaturinaktivierung der Gewebsatmung

Summary (1) Tissue slices of the liver and pieces of the skin of summer-frogs were incubated at 47.5°C for 30–150 min. Their respiration was measured during this incubation period and thereafter at a temperature of 37.5°C.(2) As a sign of an irreversible inactivation of the enzymes, the average respiration was inhibited. However, after certain periods of incubation at 47.5°C, over-shoot phenomena in the O₂-uptake at the temperature of 37.5°C were seen.     

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.     

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).     

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 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.     

(−)-Epigallocatechin gallate,a polyphenolic tea antioxidant,inhibits peroxynitritemediated formation of 8-oxodeoxyguanosine and 3-nitrotyrosine

Reaction with peroxynitrite at pH 7.4 and 37°C was found to increase the 8-oxodeoxyguanosine levels in calf thymus DNA 35-38-fold. This oxidation of deoxyguanosine, as well as the peroxynitrite-mediated nitration of tyrosine to 3-nitrotyrosine, was significantly inhibited by ascorbic acid, glutathione and (–)-epigallocatechin gallate, a polyphenolic antioxidant present in tea. For 50% inhibition of the oxidation of deoxyguanosine to 8-oxodeoxyguanosine, 1.1, 7.6 of 0.25 mM ascorbate, glutathione or (–)-epigallocatechin gallate, respectively, was required. For 50% inhibition of tyrosine nitration, the respective concentrations were 1.4, 4.6 or 0.11 mM. Thus, (–)-epigallocatechin gallate is a significantly better inhibitor of both reactions than either ascorbate or glutathione. Reaction of (–)-epigallocatechin gallate with peroxynitrite alone resulted in the formation of a number of products. Ultraviolet spectra of two of these suggest that the tea polyphenol and/or its oxidation products are nitrated by peroxynitrite.     

Modification of theophylline-induced lipolysis in human fat cells after trypsination

Summary Trypsin-treatment of human fat cells results in the potentiation of the lipolytic response and the cAMP accumulation induced by theophylline (5·10^–4 M) but not of those induced by theophylline (5·10^–3 M). The amount of cAMP formed after exposure to theophylline (5·10^–3 M) plus norepinephrine (5·10^–6 M) remains, however, 2.6fold higher in trypsin-treated human fat cells than in the control ones.Acknowledgments. The authors gratefully acknowledge the help of the surgical staff of the C. H. I. of Poissy. This work was supported by grants from the C. H. I. of Poissy and from the Université René Descartes.