Two types of heat tolerance in FHM-cells. Induction by heat-shock versus elevated culturing temperature

1. 1.Increased heat tolerance in FHM-cells from Pimephales promelas (Pisces) can be induced by culturing the cells at elevated temperatures (heat resistant acclimation) as well as by heat shock (heat hardening).

2. 2.After shift of culturing temperature (CT) from 16 to 32°C both effects are detectable with different temporal patterns.

3. 3.Cellular concentrations of heat-shock proteins correlate with the hardening effect but not with heat resistance acclimation.

4. 4.Several culturing temperature specific proteins were detected. The patterns of some enzymes are also altered by culturing temperature.

5. 5.Heat resistance acclimation is not caused by selection of a thermoresistant subpopulation of cells.

6. 6.Heat hardening and heat resistance acclimation must be distinguished as different phenomena in FHM-cells.

The selection and genetic analysis of esterase electromorphs in an organophosphate-resistant strain ofCulex pipiens from Italy

An Italian organophosphate-resistant strain ofCulex pipiens (Lucca) was found to be polymorphic for elevated and nonelevated esterases. Selection for high esterase activity produced a strain homozygous for elevated esterases A2 and B2. Selection for low activity produced a strain homozygous for nonelevated esterases, A4ⁱ and B1ⁱ. Crossing experiments showed that A2 and B2 are coded by separate but closely linked genes, as are A4ⁱ and B1ⁱ. Results indicate that elevated A2 and nonelevated A4ⁱ are alleles of a single gene (Est-3 locus), as are elevated B2 and nonelevated B1ⁱ (Est-2 locus). Selection for electromorph variants gave four elevated A variants and three elevated B variants. These esterases were not selected in the field. In Lucca, A2 and B2 replaced A1, suggesting a selective advantage to the former over the latter in the presence of chlorpyrifos. It is hypothesized that the degree of amplification is an important factor in the selection of a particular esterase electromorph as a resistance mechanism and that migrating individuals with amplified genes could have an advantage when invading a population under selection.     

淡色库蚊酯酶等位基因及其在自然种群中的频率分布

酯酶基因扩增所产生的酯酶活性升高是库蚊Culex pipiens对有机磷杀虫剂抗性的主要机理之一。采用分子杂交技术和限制性酶切片段长度多态性(RFLP)分析,已鉴定出多种酯酶等位基因类型。该文通过酯酶基因特异性片段的PCR扩增及扩增片段的酶切片段分析,对淡色库蚊Culex pipiens pallens四种有机磷抗性品系的酯酶等位基因进行分型,并测定分析自然种群中不同酶型的频率分布。研究结果表明：PCR分型方法具有快速、准确的特点。不同的有机磷杀虫剂对酯酶等位基因具有明显的选择作用。双硫磷品系为B₁型;毒死蜱和敌百虫品系为B₂型;马拉硫磷品系为B₁型和B₁/B₂杂合型。不同地区采集的种群表现出不同的酶型频率分布。该文就杀虫剂对酯酶等位基因选择作用及自然种群的酶型频率分布进行了讨论。     

The relation of changes in the individual levels of heat resistance of muscle tissue to their initial values during heat acclimation of Asellus aquaticus

1. 1.|In hog slater, Asellus aquaticus, five extremities were consecutively isolated in the course of heat acclimation to study the pattern of changes in the level of the heat resistance of muscle tissue of each single specimen.

2. 2.|The initial response of the population, during acclimation, is for the muscle resistance of different individuals to become less varied. Then a simultaneous increase in tissue resistance occurs in all ammals, which is complete by the 6th day of acclimation. Afterwards the heat resistance of muscles in the majority of animals shows little change and then, in spite of maintenance of acclimation, it starts to return to its initial level.

3. 3.|Thermal acclimation causes a temporary decrease in the variability of the heat resistance of the muscle tissue and also a temporary stabilization of this physiological characteristic to a new level. This phenomenon is a phenotypical masking of genotypic differences in a physiological characteristic in the population studied during changes in environmental temperature.

4. 4.|At all the stages of acclimation the relation of individual increases in cellular heat resistance to their initial levels follows a hyperbolic exponential equation. This implies that to a rise in environmental temperature a population responds as an integral functional system.

在无杀虫剂压力下淡色库蚊的抗性稳定性研究(英文)

本文对淡色库蚊（Ｃｕｌｅｘ ｐｉｐｉｅｎｓ ｐａｌｌｅｎｓ Ｃｏｑｕｉｌｌｅｔｔ）的毒死蜱抗性品系、抗一敏杂交品系及抗性酯酶Ｂ_２纯合品系在无杀虫剂压力选择下的抗性水平变化进行了研究。结果表明,在毒死蜱抗性品系中,抗性水平逐代下降,ＬＣ_（５０）从Ｆ_０代的０．２０９９ｍｇ／Ｌ快速降至Ｆ_８代的０．０２６２ｍｇ／Ｌ,然后继续缓慢地降至Ｆ_（１６）代的０．０２０７ｍｇ／Ｌ。从毒死蜱抗性品系中的这种抗性水平下降,可以推断该品系中并不是纯的高抗性酯酶基因扩增个体,在传代中抗性个体的比例由于其生物学方面的不适应性而逐步减少。本研究中的抗性品系与敏感品系的杂交群体的抗性变化趋势也证实了这种推理。在纯的抗性酯酶Ｂ_２基因扩增品系中,抗性水平则在后代中基本上保持稳定,并且所有的个体抗性水平和酯酶活力水平更趋集中。本文进一步对蚊虫抗性的演替进行了讨论。     

Relationship between the heat resistance of different muscles and frog viability during heat selection]

An attempt was made to elucidate the relation between the survival of mature frogs Rana temporaria during sudden (unforeseen) thermal selection and the heat resistance of several muscles: m. interfalangealis, m. ileofibularis, m. sartorius, m. gastrocnemius and m. rectus abdominis. It has been found that of greater selective value are the individuals with lower heat resistance not in all muscles, but in those having lesser heat resistance, such as m. ileofibularis and m. sartorius.     

Physiological polymorphism of a population of the common frog. II. The polymorphism of the type of muscle tissue heat resistance in stress]

A study was made of the dynamics in the heat resistance of m. interphalangealis of individual grass frogs under stress. The response of muscle tissue to injury can be differentiated into three types according to the initial heat resistance level: increase, decrease and phase change of the resistance. The pattern of response of muscle tissue of individual frogs to stress is one of manifestationss of physiological polymorphism of the population.     

Comparison of the heat resistance of ATP-hydrolyzing enzymes in 2 species of frogs

A comparison was made between the heat resistance levels of two enzymatic preparations: the actomyosinic and the transport ATPases of two species of frogs (grass and lake frogs) differing in their thermophilia. The interspecies differences in the heat resistance were found to be 6 degrees C for the actomyosinic and 3 degrees C for the transport ATPase in favour of the more thermophilic lake frog. In both species the myosinic ATPase is more sensitive to heat than the transport one. The high heat resistance of the transport ATPase is due to a higher threshold of its sensitivity to temperature.     

The effect of photoperiod on changes in plasma, glucose, cholesterol, and free fatty acids during cold acclimation in frogs

1. Many previous experiments on cold acclimation in frogs were carried out on animals maintained in total darkness. I tested the effect of photoperiod on changes in plasma FFA, glucose, and cholesterol during cold acclimation. 2. Hematocrit levels were lower whereas plasma FFA levels were higher in frogs kept in total darkness during cold acclimation. 3. Plasma glucose and plasma cholesterol levels were not affected by photoperiod during cold acclimation.     

STABILITY OF ORGANOPHOSPHATE RESISTANCE IN CULEX PIPIENS PALLENS COQUILLETT UNDER RELAXATION OF INSECITICDE SELECTION*

Abstract The stability of resistance in the organophosphate resistant strain of Culex pipiens pallens with amplification of single gene coding for esterase B₂ was determined under relaxation of insecticide selection. Insecticide resistance and amplification of esterase were both lost when strains were not homozygous for the presence of amplified gene, probably due to biological disadvantage of the esterase gene. LC₅₀ and LC₉₅ of chlorpyrifos for this strain were 0. 2099 mg/L and 0.9036 mg/L in the F₀ generation respectively, but 0. 0207 mg/L and 2. 8027 mg/L respectively in the F₁₆ generation. In the homozygous strain, insecticide resistance was still stable and amplification of esterase remained after 16 generations under relaxation of insecticide selection, which indicated that copy of esterase gene was not lost in the offspring of this strain. The evolution of insecticide resistance in mosquitoes is discussed.     

Effect of temperature on freezing and heat stress tolerance of cultured plant cells

The relationship between freezing and heat tolerance was investigated with suspension-cultured pear (Pear cammunis cv. Bartlett) cells. This culture showed considerable capacity for both cold and heat acclimation. Growth at 2 °C (Cold acclimation) and at 30 °C (heat acclimation) both increased the freezing tolerance [measured via triphenyltetrazolium chloride (TTC) reduction]of pear cells. However, heat acclimation induced by heat shock treatment did not significantly effect freezing tolerance. Although growth at 30 °C increased freezing tolerance (relative to 22 °C-grown controls), growth at 2 °C (cold acclimation) decreased heat tolerance substantially. Thus, the only similarity detected between cold and heat acclimation was that both processes conferred freezing resistance to TTC-reducing system(s) in pear cells. The pear suspension culture will be a useful tool to further investigate cold acclimation via comparisons between heat and freezing acclimation and injury.     

Soluble proteins and isoenzymes from seeds of diverse male steriles of sorghum, (Sorghum bicolor (L.) Moench)

Summary A comparison of soluble protein, esterase, GDH and ADH isoenzyme patterns in seeds of different steriles, maintainers and restorer lines exhibited similarities as well as differences. Soluble protein patterns from sterile and maintainer lines differed both qualitatively and quantitatively. Based on the esterase patterns, male steriles with different cytoplasms could be separated into three groups (i) Ck 60A and B; Nagpur A and B, (ii) M 35-1A and 1 B, M 31-2A and 2B, (iii) G1A and B, VZM2A and 2B. Each group could further be differentiated on the basis of minor differences in esterase isoenzyme patterns within each group. ADH and GDH patterns in general were similar in both sterile and maintainer lines.Abbreviations ADH Alcohol dehydrogenase - GDH Glutamate dehydrogenase - NAD Nicotinamide adenine dinucleotide     

Identification of a cocaine esterase in a strain of Pseudomonas maltophilia.

A strain of Pseudomonas maltophilia (termed MB11L) which was capable of using cocaine as its sole carbon and energy source was isolated by selective enrichment. An inducible esterase catalyzing the hydrolysis of cocaine to ecgonine methyl ester and benzoic acid was identified and purified 22-fold. In the presence of the solubilizing agent cholate, cocaine esterase had a native Mr of 110,000 and was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be a monomer. In the absence of cholate, cocaine esterase had a native Mr of 410,000 and probably existed as a tetramer. The pH optimum of the enzyme was 8.0, and the Km values for cocaine, ethyl benzoate, and ethyl 2-hydroxybenzoate were 0.36, 1.89, and 1.75 mM, respectively. Inhibition studies indicated that the enzyme was a serine esterase, possibly possessing a cation-binding site similar to those of mammalian acetylcholinesterase and the atropine esterase of Pseudomonas putida PMBL-1. The cocaine esterase of P. maltophilia MB11L showed no activity with atropine, despite the structural similarity of cocaine and atropine.     

Thyroid activity in common frogs and the heat resistance of their bodies and muscle tissue

Thyroid activity of single individuals of the grass frog has been studied during winter hybernation (2-5 degrees) and heat acclimation (15 degrees) in relation to the heat resistance of the organism and muscle tissue at 2-5 degrees. A positive correlation has been observed between thyroid activity and the organismal heat resistance. At 15 degrees thyroid activity increases. It is the highest in females with a low initial heat resistance of the organism. It is assumed that changes in the heat resistance of the organism and muscle tissue are controlled by the thyroid gland. However, no correlation has been found between the initial (winter) level of the heat resistance of muscle tissue and the activity of thyroid.     

白细胞酯酶同工酶对胃癌诊断价值的探讨

本文应用薄平板等电聚焦电泳法对15例未经手术治疗的胃癌患者进行了外周血白细胞酯酶同工酶的分离.结果:正常人外周血白细胞酯酶同工酶显示12条带,等电点(PI)为3.73～7.80.胃癌患者显示11条带,与正常相比第十二条带缺如,PI为3.80～7.90.同工酶各分带与正常相比,酶活性发生明显异常(P<0.01).提示;胃癌患者酯酶同工酶的改变可能是胃癌早期诊断的酶学指标.     

Thermal acclimation in Arabidopsis lyrata: genotypic costs and transcriptional changes

Frost and heat events can be challenging for sessile organisms that cannot escape thermal extremes. However, adverse effects of thermal stress on fitness may be reduced by pre‐exposure to cold or heat, a process known as acclimation. To understand the ecological and evolutionary implications of acclimation, we investigated (1) the reduction in performance due to stress pre‐exposure, (2) the magnitude of increased leaf resistance to subsequent stress, (3) the costs of acclimation and (4) the genes differing in expression due to stress pre‐exposure. Plants of Arabidopsis lyrata were raised under three treatments of pre‐exposure: bouts of frost, bouts of heat or constant temperature. Resistance of leaves to subsequent frost and heat stress was then measured by electrolyte leakage. RNA‐seq analysis was performed to examine the genes differentially expressed between stress‐pre‐exposed and control plants. Pre‐exposure to stress during growth decreased plant size and increased leaf resistance to subsequent stress independent of whether pre‐exposure was to frost or heat. But the highest increase in leaf resistance to frost was found after pre‐exposure to frost (as a trend) and in leaf resistance to heat after pre‐exposure to heat. No evidence for costs of acclimation was detected. RNA‐sequencing suggested that acclimation by frost and heat pre‐exposure was caused by distinct mechanisms: modification of the chloroplast membrane and modification of the cell wall and membrane, respectively. Our results suggest that thermal resistance is a labile complex of traits, strongly affected by the previously experienced stress environment, with undetermined costs.     

Elevated temperature as a treatment for Batrachochytrium dendrobatidis infection in captive frogs

The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian declines worldwide. In vitro laboratory studies and those done on wild populations indicate that Bd grows best at cool temperatures between 17 and 25 degrees C. In the present study, we tested whether moderately elevating the ambient temperature to 30 degrees C could be an effective treatment for frogs infected with Bd. We acquired 35 bullfrogs Rana catesbeiana from breeding facilities and 36 northern cricket frogs Acris crepitans from the wild and acclimated them to either 23 or 26 degrees C for 1 mo. Following the acclimation period, frogs were tested for the presence of Bd using qPCR TaqMan assays. The 12 R. catesbeiana and 16 A. crepitans that tested positive for Bd were subjected to 30 degrees C for 10 consecutive days before returning frogs to their starting temperatures. Post-treatment testing revealed that 27 of the 28 frogs that had tested positive were no longer infected with Bd; only a single A. crepitans remained infected following treatment. This result indicates that elevating ambient temperature to a moderate 30 degrees C can be effective as a treatment for Bd infection in captive amphibians, and suggests that heat may be a superior alternative to antifungal drugs.     

Effect of cold acclimatization of grass frogs on the heat resistance of their somatic muscles in summer]

During cold acclimation (+5 degrees C) of the grass frog Rana temporaria L. changes in heat resistance were observed for six of seven skeletal muscles examined. Changes in the resistance of different muscles were directed differently. Low-resistant muscles demonstrated an increased resistance, wheras high-resistant muscles showed a decrease resistance. Within 24 hours of acclimation, all the muscles demonstrated totally decreased heat resistance. By the end of acclimation (30 days), the resistance of muscles increased to approach the initial level. On the background of those situation changes, seasonal changes in resistance of muscles proceeded.     

Correlations between measures of heat resistance and acclimation in two species of Drosophila and their Hybrids

Associations between traits may differ at the interspecific and intraspecific levels, making it difficult to predict long term evolutionary constraints. In this study we used replicate hybrid lines generated from crosses between Drosophila serrata and D. birchii to investigate correlations between measures of heat resistance and acclimation responses. Within each species, knockdown heat resistance was uncorrelated with heat resistance as measured by mortality. In contrast, D. serrata was more resistant than D. birchii for both measures of heat resistance. Thus, inter- and intraspecific correlations between measures of heat resistance differ. In the hybrids, there was no evidence for a correlation between knockdown time and heat induced mortality. Hybrid data did suggest a trade-off between acclimation for knockdown heat resistance and heat resistance as measured by mortality. We argue that hybrids between species are a potentially useful tool for studying traits such as acclimation responses that show litde genetic variation within species.