Rapid cold-hardening in Zaprionus vittiger (Coquillett) (Diptera: Drosophilidae)

Low temperature injury can be significantly reduced by pre-treatment at sub-lethal low temperatures of only a few hours--a phenomenon termed 'rapid cold-hardening' (RCH). However, most studies to date have focused extensively on only a few key insect taxa, e.g. Drosophila melanogaster within the Drosophilidae family. Further studies on other closely-related species are required to better understand evolutionary and ecological variation in the magnitude of the RCH response in terrestrial arthropods. Here, we investigated RCH in a previously unstudied fruit fly, Zaprionus vittiger, following a range of high and low pretreatment temperatures. There was a significant improvement in Z. vittiger survival of lethal temperatures (2 h at -3 degrees C) following a 2 h pretreatment at 4, 7 and 10 degrees C as well as 30 degrees C for 2 h. Maximum survival (60-70%) during RCH was achieved following hardening at 7 degrees C and 10 degrees C but is lower than some Drosophila species under similar treatment conditions. Therefore, since RCH was detected in a confamilial species, we propose that RCH might be a widely conserved response to temperature variation in the family Drosophilidae, although some variation in the magnitude of the response can be detected.     

Cryopreservation of shoot tips of Picrorhiza kurroa Royle ex Benth,an indigenous endangered medicinal plant,through vitrification

The cryopreservation of shoot tips of Picrorhiza kurroa Royle ex Benth (IC 266698), an endangered medicinal plant of India was investigated. Shoot tips (about 1 mm in length) excised from four-week-old proliferating shoot cultures were precultured on MS medium supplemented with various osmotica before dehydrating with PVS2 solution at 0 degrees C. The dehydrated shoot tips were directly immersed in LN2. Following cryopreservation, and after rapid rewarming at 45 degrees C, shoot tips were quickly washed with 1.2 M sucrose solution and then plated on solidified shoot culture medium. Shoot tips were successfully cryopreserved by vitrification, when they were precultured on medium supplemented with 5% DMSO at 4 degrees C for two days before dehydrating in PVS2 for 10-20 minutes at 0 degrees C. Average survival in terms of normal shoot formation after 4 wks of plating was about 20% without callus formation. Cold hardening of shoot cultures for four weeks at 4 degrees C significantly improved the survival and shoot regeneration of cryopreserved shoot tips to 70% and 35%, respectively.     

Supercooling capacity and cold hardiness of the adults of the sycamore lace bug, corythucha ciliata (Hemiptera:Tingidae)

Supercooling point (SCP) of female adults of Corythucha ciliata was significantly lower than that of male adults, with an average being -11.49 degrees C and -9.54 degrees C, respectively. Low temperature survival of adults of different ages indicated that there were differences in cold survival ability among age groups of adults. Nonlinear regression analysis found that the response of C. ciliata adults to exposure time under different low temperature regimes (above -5 degrees C) was best fitted by a logistic equation. Both low temperature and exposure time had significant effects on mortality of adults. Temperatures above 5 degrees C did not prevent C. ciliata adults from surviving. C. ciliata was shown to be a freeze-intolerant but chill-tolerant insect. C. ciliata could tolerate subzero temperatures by supercooling. Temperature around -8 degres C is a critical point for successful overwintering of C. ciliata adults, which can establish in the whole areas where Platanus trees are planted in China.     

原子吸收光谱法测定与分析榛子抗寒性的研究

以榛子一年生枝条为试材,利用原子吸收光谱法和电导法分别测定与分析榛子3个种(6个无性系)不同低温处理后的K+渗出率和电解质渗出率,并建立了各无性系的低温-K+渗出率及低温–电解质渗出率回归模型。结果表明：利用2种方法综合评价各无性系抗寒能力结果一致,原子吸收光谱法测定K+渗出率指标可作为榛子无性系抗寒性的一种早期鉴定手段;6个无性系抗寒性大小排序为：C₇R₇＞Z-9-40＞C₆R₁＞CS₂R₁＞Z-9-22＞Z-9-30,3个种的抗寒性强弱顺序为：平榛＞平平欧杂交榛＞平欧杂交榛;各无性系半致死温度在-26～40 ℃之间。     

Cold resistance in the lesser mealworm Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae)

We have investigated cold resistance, measured by the supercooling point (SCP) temperature, in life stages of the lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae), collected in Brittany poultry houses. Mean SCP values drastically increased during the insect ontogeny: egg (-26.1 C), first instar larvae (-21.6 C), last instar larvae (-15.5 C), pupae (-11.6 C), teneral adults (-12.0 C) and mature adults (-13.1 C). Nymphal metamorphosis and adult maturation did not promote substantial decrease of freezing resistance. The SCP values reflect the physiological states of the developmental stages especially the absence of ice nucleating agents: (i) lower SCP values in egg and unfed newly-emerged larvae I (i.e. -25.1 C), (ii) higher SCP values in fed larvae (i.e. -14.7 C), pupae and adults most likely due to the presence of ice nucleation sites in the gut. A tropical species, A. diaperinus, seems not to use its potential cold hardiness even in winter to remain in this warm habitat in temperate regions.     

Thermal analysis of the plant encapsulation-dehydration cryopreservation protocol using silica gel as the desiccant

The encapsulation-dehydration cryopreservation protocol is critically dependent upon the evaporative desiccation step, which must optimise survival with the retention of glass stability on sample cooling and rewarming. Desiccation is usually achieved evaporatively by drying in a sterile airflow. However, chemical desiccation using silica gel has advantages for laboratories that do not have environmental control and/or which are exposed to high relative humidities and risks of microbial contamination. This study characterised thermal profiles of silica gel-desiccated encapsulated shoot-tips of two Ribes species using Differential Scanning Calorimetry. For both species silica gel-desiccation at 16 degrees C for 5 h decreased bead water content from ca. 75 to 28% fresh weight (3.8 to 0.4 g x g(-1) dry weight); further desiccation (for 6 and 7 h) reduced the bead water content to 21% (0.3 g x g(-1) dry weight). These changes in water status altered the thermal properties of beads for both species. After 7 h desiccation over silica gel stable glass transitions were observed on both cooling and rewarming of beads containing meristems. Tg mid-point temperatures ranged from -78 to -51 degrees C (cooling) and from -88 to -54 degrees C (warming) [at cooling and warming rates of 10 and 5 degrees C min(-1), respectively] after 5 to 7 h silica gel-desiccation. Post-cryopreservation viability of both species was ca. 63%. Thermal analysis studies revealed that an encapsulation/dehydration protocol using silica gel as a desiccant should comprise a minimum 5 h drying (at 16 degrees C). This reduces bead moisture content to a critical point (ca. 0.4 g x g(-1) dry weight) at which stable glasses are formed on cooling and rewarming. It is concluded that silica gel has advantages for use as a desiccant for alginate-encapsulated plant meristems by promoting stable vitrification and is useful in laboratories and/or geographical locations where environmental conditions are not under stringent control.     

温度对氨基苯甲酸在粗糙银表面上行为的影响

本文同时测定了当温度从－１９０℃上升到３０℃和从３０℃下降到－１９０℃对氨基苯甲酸（ｐ－Ａｍｉｎｏｂｅｎｚｏｉｃ Ａｃｉｄ，ＰＡＢＡ）和邻氨基苯甲酸（ｏ－Ａｍｉｎｄｂｅｎｚｏｉｎ Ａｃｉｄ，ＯＡＢＡ）在粗糙的银表面上的表面增强拉曼光谱的变化。结果表明，若吸附质表面拉曼光谱的增强主要表现为化学机理，且整个分子平躺在表面，则分子在表面上的取向不会随温度的变化而改变。而温度的变化会引起基于电磁场增强机理     

Novel approach to evaluate the interaction of pulsed ultrasound with embryonic development

An in vitro whole-embryo culture system was used which allowed ultrasound to interact directly with rat embryos, at 9.5 days of gestation, under conditions of controlled temperature. Neural plate damage, expressed during a critical period of forebrain development, was evaluated 48 h post-insonation. Ultrasound-induced effects were thus identified in the absence of significant temperature changes or complications from the influence of maternal physiology. Exposures to 3.2 microseconds pulses of 3.14 MHz ultrasound at a PRF of 2 kHz and 1.2 W cm-2 intensity (ISPTA) for durations of 5, 15 or 30 min produced no major morphological abnormalities at a temperature of 38.5 degrees C. Embryonic response to stress was evidenced by changes in protein synthesis, and delayed development was indicated by a reduction in somite number. These effects were enhanced when the insonation temperature was elevated by 1.5 degrees C.     

The study of heat stress in tomato fruits by NMR microimaging.

The ripening of the tomato fruit was delayed for several days (average 5 days) by a 1-day heat treatment at 42 degrees C. Ethylene production increased during the first 3 h, but, after 6 h inhibition was almost total in tomato fruit incubated at 42 degrees C. However, recovery of ethylene production was rapid if fruits were returned to a temperature of 25 degrees C after heating. In NMR microimaging, three imaging pulse sequences with different repetition and echo times at 42 degrees C were used to obtain the proton density (TR = 6000 ms, TE = 15 ms), the T1 weighted image (TR = 1000 ms, TE = 15 ms) and the T2-weighted image (TR = 6000 ms, TE = 120 ms). After 12 h heating, the water in locular tissues began to show shorter T1 and T2 values. Though the tomatos were returned to 25 degrees C and preserved one more day, the water having a shorter T2 value in locular tissues, did not change. These results show that tomato fruit do not fully recover from heating even after one day, although ethylene production is recovered almost immediately. For this reason, we suggest that some denaturation event inside the tomato, which goes on after the end of heating, is the cause of the delay in tomato ripening.     

High resolution electron microscopy of precipitates in high Co-Ni alloy steel

In the secondary hardening reaction in ultrahigh strength steel of high Co-Ni alloy, the needle-shaped precipitating carbide is the main strengthening phase. Particular attention has been paid to the nucleation, growth and coarsening of the precipitate and its interface with the ferrite matrix. High resolution transmission electron microscopy observations show that when tempered at a low temperature condition of 454 degrees C for 5h, the precipitating carbides begin to nucleate in the form of clusters; at peak hardening tempered at 482 degrees C, the growing carbides are fully coherent with the matrix, exhibit black-white contrast in bright-field images and have their own hexagonal crystalline structure as M(2)C. Coarsening carbides tempered at high temperature lost their coherence and exhibited Moiré fringes. Lattice images directly indicate the crystallographic relationship of M(2)C carbides and ferrite, [100](alpha)//[1101](beta), [100](alpha)//[1120](beta).     

Observation of anti-stokes fluorescence cooling in thulium-doped glass

We report the first observation of anti-Stokes fluorescence cooling in a thulium-doped solid with pump excitation at 1.82 &mgr;m相似文献   

热加工对花生过敏原Ara h 2抗原性及构象的影响

从花生种子中分离纯化花生过敏原Ara h 2,采用酶联免疫吸附试验(ELISA)、圆二色谱(CD)、ANS荧光探针及紫外可见(UV-Vis)光谱等方法,系统研究热加工对Ara h 2抗原性和结构的影响.结果表明:Ara h 2蛋白经55或70℃处理后其抗原性略有升高,经85,100或115℃处理后,其抗原性显著降低,且随着温度和时间的增加其抗原性均不断降低.CD色谱分析表明,Ara h 2经热处理后其二级结构发生变化;ANS荧光探针光谱显示,不同的热处理均导致Ara h 2表面疏水性增加.紫外光谱显示,不同温度对Ara h 2处理30 min后(除55℃外),其紫外吸收值均升高.Ara h 2经100℃处理不同时间后,其紫外吸收值均有增加.由此推断,花生过敏原Ara h 2的构象改变导致了其抗原性的降低.     

Vacancy–solute interactions during ageing of a cold-worked Mg–RE-based alloy

The vacancy–solute interactions during artificial ageing at 250^○C of cold worked samples of a commercial magnesium alloy WE54 (Mg–RE based) were studied by coincidence Doppler broadening of positron annihilation radiation and positron annihilation lifetime spectroscopy. The results show that, in the as-cold-worked state, the vacancies are associated with dislocations that are generated by the cold work and that, after artificial ageing at 250^○C, the vacancies are associated with solute elements and help the formation of precipitate precursors. This mechanism accelerates the formation of hardening precipitates without any apparent changes in the precipitation sequence and in the products of the decomposition of the supersaturated solid solution. The present study demonstrates that the stronger hardening response achieved in the cold-worked samples originates from the presence of a higher concentration of vacancies that is introduced by the cold work and is retained in the first few minutes of ageing.     

Rapid cold hardening: a gut feeling

This study examined the rate of cold hardening of a field population of Antarctic springtails and the effect of eating food with particular levels of ice nucleating activity on the animal's whole body freezing point. The SCPs of samples of c. 20, freshly collected, Cryptopygus antarcticus were measured hourly over a 32 hour collection period using differential scanning calorimetry and related to habitat temperature. The mean SCP of the springtails increased from -24 to -10 degree C during which time the habitat temperature warmed slowly from -2.5 to +2.5 degree C. In laboratory experiments, previously starved, cold tolerant springtails were fed on selected species of algae with measured SCP's but there was no clear correlation between the SCP of food and that of the animals after feeding. Microscopic examination of faecal pellets and guts from springtails showed that algal cells were completely destroyed during digestion.     

Purification and characterization of uridine phosphorylase from the ice-nucleating bacterium, Pantoea agglomerans NBRC12686

The ice-nucleating bacterium, Pantoea agglomerans NBRC12686 responds to a decrease in temperature with the induction of proteins, which are classified as cold-induced proteins. When the temperature of the strain NBRC12686 culture was lowered from 30 degree C to 12 degree C, the viability after freezing treatment significantly improved. By the use of SDS-polyacrylamide gel electrophoresis and high-performance liquid chromatography (HPLC), we analyzed the cold acclimation response in strain NBRC12686. After a shift from 30 degree C to 12 degree C, several proteins and saccharides were synthesized. After 48 h of cold acclimation, the induction level of proteins increased. In addition, ribose-1-phosphate was fractionated by HPLC using a TSK gel Sugar AXG column. Cell-free extracts were prepared from a cold acclimation culture (30 degree C to 12 degree C) and a non-cold acclimation culture (30 degree C), and then subjected to SDS-PAGE. A protein of approximately 29.7-kDa was present in the cold acclimation culture but was not present in the non-cold acclimation culture. The 29.7-kDa protein was purified by various chromatographies. We found that apparent molecular mass of the protein was approximately 119-kD constructed of 4 subunits of 29.7-kDa each. Based on the analysis of the N-terminal amino acid sequences of proteins, the 29.7-kDa protein had 83 percent identity with that of uridine phosphorylase (UPase) obtained from Escherichia coli K-12. We confirmed that the 29.7-kDa protein was novel, judged by molecular mass different from the already-known UPase or cryoprotectants. The cryoprotective activity of UPase of 29.7-kDa protein for LDH was approximately 30 percent at 5.0 microgram per ml of the protein. Furthermore, UPase had a high level of cryoprotective activity even after treating at 70 degree C for 30 min, but had no activity after treating at 100 degree C. We could elucidate that UPase from strain NBRC12686 had a cryoprotective activity as well as an enzyme activity, and it seems that UPase works in two different mechanisms for freezing tolerance.     

气相质谱法对小鼠体内甲苯二异氰酸酯代谢产物的鉴定分析

应用气相质谱测定小鼠体内甲苯二异氰酸酯(TDI)的代谢产物,并鉴别了其在机体中的代谢途径。TDI色谱条件为Supelco PTETM-5色谱柱(30 mm×0.25 mm×0.25 μm),起始柱温90 ℃保持30 min,以40 ℃·min-1升至280 ℃,保持5.25 min;汽化室温度250 ℃;载气为氦气,流速为1.0μL·min-1。TDI体内代谢产物色谱条件为30+2mX0.25+0.02mm 94%甲基、4%乙烯基键合相弹性石英毛细柱,起始温度30 ℃保持5 min,以8 ℃·min-1升至280 ℃,保持5 min。汽化室温度250 ℃;载气为氦气,流速1.0μL·min-1。质谱条件为电离方式EI,电离能量70eV,连接管温度280 ℃,扫描范围35～350μ;进样量1.0μL。结果表明2,4甲苯二异氰酸酯在血液、尿液、粪便中都被代谢成为2,4甲苯二胺。GC-MS法可有效分离并鉴定TDI体内代谢产物。     

Survival of freezing by free-living Antarctic soil nematodes

Free-living microbivorous nematodes become numerically dominant in Antarctic terrestrial faunas as environmental conditions become more severe, while also reaching very high levels of abundance in moist, vegetated habitats. Nematodes have little resistance to freezing via exogenous ice nucleation, such as would occur as their microhabitat freezes. We report the results of experiments testing the ability of seven maritime Antarctic nematode taxa to survive freezing in small water droplets at high sub-zero temperatures. Isolated individuals of these species possessed supercooling characteristics similar to those previously reported (supercooling points -6 to -25 degree C). When frozen in water at -3 to -6 degree C, most showed high (> 70%) survival both (i) after rapid cooling (1 degree C/min) to c. -60 degree C followed by immediate rewarming, and (ii) when held for 7-12 h at either -10 or -30 degree C, although the proportions surviving varied between species. We propose that the ability to survive freezing while fully hydrated at high sub-zero temperatures is one of the most important aspects of these species' survival tactics.     

Cryopreservation of basal stem buds of in vitro-grown mat rush (Juncus spp.) by vitrification

An optimal protocol for the cryopreservation of in vitro-grown mat rush (igusa) buds by vitrification has been successfully developed. Established multiple stemmed cultures, which were induced in liquid MS medium containing 8.9 microM BA by roller culture, were cut into small clumps, plated on solid MS medium and cultured for three weeks at 25 degree C. Clumps that grew many buds were cold-hardened at 5 degrees C, with an 8 h photoperiod, for more than 30 d. The basal stem bud (1 to 2 mm long) was dissected from the clumps and precultured at 5 degrees C for 2 d on solid MS medium containing 0.3 M sucrose. The precultured buds were placed in 2 ml plastic cryotubes and osmoprotected with 1 ml loading solution containing 2 M glycerol and 0.6 M sucrose for 30 min at 25 degree C. Then they were dehydrated in 1 ml PVS2 solution at 25 degree C for 30 min and immersed in liquid nitrogen. Using this protocol, the survival level of cryopreserved igusa 'NZ219' buds reached 87 percent. This protocol was successfully applied to 42 different lines from three Juncus species, which had relatively high survival levels ranging from 30 to 90 percent and an average of 63 percent.     

冷轧和退火对V-5Cr-5Ti合金组织结构和抗辐照硬化性能的影响

钒合金(V-5Cr-5Ti)是聚变堆第一壁以及包层的重要候选结构材料。不同加工工艺会对钒合金在聚变堆中的服役性能产生影响。本文利用兰州重离子研究装置(HIRFL)提供的337 MeV的高能Fe离子对不同程度冷轧(冷变形量分别为40%、60%和80%)以及冷轧后退火(1 273 K退火1 h)的V-5Cr-5Ti合金样品进行了辐照,研究了不同的冷轧和退火处理过程对材料抗辐照硬化性能的影响。电子背散射衍射技术(EBSD)测试结果显示,随着冷变形量的增加,样品中细小破碎晶粒比例增大,晶粒平均尺寸减小。退火处理后,细小破碎晶粒出现一定程度的长大,大晶粒几乎全部消失,晶粒尺寸分布更加均匀。维氏硬度结果表明随着冷变形量的增加,硬度随之增加,退火后硬度降低。辐照之后,材料硬度升高,出现了辐照硬化效应。在冷轧样品和退火样品中都观察到了辐照硬化效应随冷变形量的增加显著减弱的现象,这表明冷变形可以显著提高材料的抗辐照硬化能力。结合EBSD和硬度数据,对冷变形和退火处理引起钒合金抗辐照硬化性能变化的机理进行了讨论。讨论结果显示,冷轧使材料总的吸收尾闾增大,引起辐照硬化程度降低,退火处理使材料中晶界密度和位错密度降低,材料的总吸收尾闾降低,辐照硬化效应增加。     

微波消解顺序注射冷蒸汽原子荧光光谱法测定沉积物中的痕量汞

提出采用密闭微波消解结合顺序注射冷蒸汽原子荧光光谱法快速测定沉积物中痕量汞的新方法。利用10%HCl-50%HNO3-40%H2O和30%HCl-20%HNO3-50%H2O两种消解体系在140℃条件下消解5min,沉积物样品消解完全,且样品消解过程中痕量汞无损失。优化条件下,线性范围0.02～30ng.mL-1,检出限为0.5ng.g-1,RSD为3.7%(n=10)。标准参考物质GSD-2,GSD-9及GSD-10的测定值与推荐值吻合,实际样品加标回收率(91.2±4.3)%～(96.5±4.6)%。本法试剂用量少,快速准确,灵敏度高,线性范围宽,适合沉积物中的痕量汞的测定,有很好的实用价值。