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101.
102.
温带地区的高山多年生草本植物可在-30℃组织结冰状况下生存,然而人们并不了解其抗冻的生理机理。本研究目的拟通过测定自然生境下生长的4种高寒山区禾本科牧草(无芒雀麦(Bromus inermis Leyss.)、花雀麦(Bromus sinensis Keng.)、垂穗披碱草(Elymus nutans Griseb.)、草地早熟禾(Poa sphyondylodes Trin.)根中渗透调节物、膜脂过氧化产物、多胺含量季节变化,以了解他们与牧草抗冻的关系。结果表明,在晚秋(9月1~15日)牧草根中MDA含量增高,尔后下降,冬季保持恒定。总碳水化合物(TNC),可溶性糖、脯氨酸、可溶性蛋白质含量随晚秋气温下降而增加,在11月达到最高,尔后下降,且持续到翌年春季。随晚秋气温下降从9月到11月根中多胺含量迅速增加,4种牧草平均增加180%,其中亚精胺(Spd)占多胺含量的53%。在11月牧草根中多胺几乎完全消失。上述物质在晚秋入冬增加正好与牧草抗冻锻炼时间相吻合,因而是植物抗冻适应的重要生理响应和植物越冬的低温保护物质。他们在降低细胞冰点、防止细胞结冰引起的膜机械伤害,抑制膜脂过氧化保护膜稳定性方面具有重要作用。 相似文献
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106.
《Reproductive biology》2014,14(4):257-261
The aims of this study were to evaluate: (1) the effect of cryopreservation on DNA fragmentation of canine epididymal spermatozoa, and (2) the potential protective effect of melatonin on post-thaw sperm quality (motility, morphology, acrosomal and DNA integrity). Epididymal spermatozoa were collected after orchiectomy of ten dogs. Sperm samples were frozen in the presence or absence of melatonin (1 mM). DNA fragmentation index (percentage of spermatozoa with fragmented DNA) was similar in fresh samples (3.3 ± 3.6) and samples frozen with (4.2 ± 3.8) or without (3.6 ± 3.7) melatonin. Sperm motility was significantly (p < 0.0001) higher in fresh compared to frozen samples. The presence of melatonin in the freezing extender did not affect the sperm motility. Proportions of spermatozoa with normal morphology were similar in fresh and frozen samples, irrespective of the presence of melatonin in the extender. Acrosome integrity was significantly decreased (p < 0.01) by cryopreservation, and melatonin did not exert any beneficial effects. In conclusion, DNA fragmentation of canine epididymal spermatozoa was not affected by the freezing procedure, and the presence of melatonin did not preserve motility and acrosome integrity which were adversely affected by cryopreservation. The evaluation of DNA status of thawed gametes is particularly relevant for epididymal spermatozoa since these spermatozoa are usually stored and used in assisted reproductive techniques. 相似文献
107.
Chikako Kuwabara Donghui WangKeita Endoh Yukiharu FukushiKeita Arakawa Seizo Fujikawa 《Cryobiology》2013
Based on the discovery of novel supercooling-promoting hydrolyzable gallotannins from deep supercooling xylem parenchyma cells (XPCs) in Katsura tree (see Wang et al. (2012) [38]), supercooling capability of a wide variety of tannin-related polyphenols (TRPs) was examined in order to find more effective supercooling-promoting substances for their applications. The TRPs examined were single compounds including six kinds of hydrolyzable tannins, 11 kinds of catechin derivatives, two kinds of structural analogs of catechin and six kinds of phenolcarboxylic acid derivatives, 11 kinds of polyphenol mixtures and five kinds of crude plant tannin extracts. The effects of these TRPs on freezing were examined by droplet freezing assays using various solutions containing different kinds of identified ice nucleators such as the ice nucleation bacterium (INB) Erwinia ananas, the INB Xanthomonas campestris, silver iodide and phloroglucinol as well as a solution containing only unintentionally included unidentified airborne ice nucleators. Among the 41 kinds of TRPs examined, all of the hydrolyzable tannins, catechin derivatives, polyphenol mixtures and crude plant tannin extracts as well as a few structural analogs of catechin and phenolcarboxylic acid derivatives exhibited supercooling-promoting activity (SCA) with significant differences (p > 0.05) from at least one of the solutions containing different kinds of ice nucleators. It should be noted that there were no TRPs exhibiting ice nucleation-enhancing activity (INA) in all solutions containing identified ice nucleators, whereas there were many TRPs exhibiting INA with significant differences in solutions containing unidentified ice nucleators alone. An emulsion freezing assay confirmed that these TRPs did not essentially affect homogeneous ice nucleation temperatures. It is thought that not only SCA but also INA in the TRPs are produced by interactions with heterogeneous ice nucleators, not by direct interaction with water molecules. In the present study, several TRPs that might be useful for applications due to their high SCA in many solutions were identified. 相似文献
108.
Effect of low and high egg yolk concentrations in the semen extender for goat semen cryopreservation
C.A.S. Bispo G. Pugliesi P. Galvão M.T. Rodrigues P.G. Ker B. Filgueiras G.R. Carvalho 《Small Ruminant Research》2011,100(1):54-58
This research aimed to evaluate two concentrations of egg yolk inclusion rates (20 and 2.5%) in the semen extender of goat semen cryopreserved during two seasons of the year. The study was conducted during a light-induced breeding season (Experiment 1), and during the natural breeding season (Experiment 2), in the southern hemisphere. Four ejaculates from each buck (n = 2) were collected in each experiment. After collection, semen was divided, with each sample being diluted in the semen extender – according to the treatments (T1 – 20% egg yolk or T2 – 2.5% egg yolk, using a glucose–EDTA extender). For T1 treatment in Experiment 2, the semen was also washed before the semen cryopreservation process. The semen samples were frozen, and after thawing evaluated for seminal characteristics i.e. sperm motility, vigor, morphology and membrane integrity. The fertilising capacity of the frozen-thawed semen was evaluated following a single artificial insemination 12 h after the onset of estrus in 50 (Experiment 1) and 60 does (Experiment 2). In Experiments 1 and 2, the mean values for sperm motility and membrane integrity of the frozen-thawed semen did not differ between the T1 and T2 treatments. However, the mean sperm vigor and morphological normal sperm were greater (P < 0.05) in T2 than T1 treatment. The fertility rates recorded did not differ between T1 and T2 treatments in Experiment 1, however, it was greater (P < 0.05) in the T2 than in the T1 treatment, in Experiment 2. According to obtained results, it can be recommended to use a glucose–EDTA extender with a low egg yolk concentration (2.5%) inclusion, for superior fertility results in goats. 相似文献
109.
<Emphasis Type="Italic">Arabidopsis rd29A::DREB1A</Emphasis> enhances freezing tolerance in transgenic potato 总被引:2,自引:0,他引:2
Behnam B Kikuchi A Celebi-Toprak F Kasuga M Yamaguchi-Shinozaki K Watanabe KN 《Plant cell reports》2007,26(8):1275-1282
The freezing tolerance of 38 independent transgenic potato lines derived from the cultivar Desiree was tested in vitro using
plantlets. The lines were transgenic for the DREB1A gene under control of the rd29A promoter, both of which were derived from Arabidopsis thaliana. The level of damage caused by freezing varied significantly among the transgenic clones and a non-transgenic control (cv.
Desiree). Phenotypic evaluation indicated that the variable responses to freezing were attributable to genotypic variation,
but freezing tolerance was not dependent on the number of insertions. Northern blot analysis using a DREB1A cDNA probe revealed high levels of DREB1A expression among the transgenic clones during the initial cold exposure at 4°C (after 2 h) and in the early stages of freezing
(−20°C, 1–10 min). Furthermore, a linear correlation was detected between the level of expression and the phenotypic response
for all lines except D138. Thus, in the case of potato, a significant increase in freezing tolerance was observed in vitro
on a small scale following the introduction of rd29A::DREB1A. Additional testing will show whether this strategy can be used for tolerance breeding in potato and to increase the freezing
tolerance of other agriculturally important crops.
Babak Behnam and Akira Kikuchi equally contributed for this work. 相似文献
110.
Temperature response curves of chlorophyll a fluorescence parameters were used to assess minimum sub-zero temperature assuring functioning of photosynthetic photochemical
processes in photosystem II (PS II) of Antarctic lichens. Umbilicaria Antarctica and Xanthoria elegans were measured within the temperature range from −20 to +10°C by a fluorometric imaging system. For potential (F
V/F
M) and actual (Φ
II) quantum yields of photochemical processes the minimum temperature was found to be between −10 and −20°C. Non-photochemical
quenching (NPQ) of absorbed excitation energy increased with temperature drop reaching maximum NPQ at −15°C. Image analysis
revealed intrathalline heterogeneity of chlorophyll a fluorescence parameters with temperature drop. Temperature response of Φ
II exhibited an S-curve with pronounced intrathalline differences in X. elegans. The same relation was linear with only limited intrathalline difference in U. antarctica. The results showed that Antarctic lichen species were well adapted to sub-zero temperatures and capable of performing primary
photosynthesis at −15°C. 相似文献