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161.
黄山风景区空气真菌组成及其生态分布 总被引:1,自引:0,他引:1
用自然沉降法采集空气真菌,对黄山风景区14 个景点的空气真菌资源及其生态分布情况进行调查.共鉴定出空气真菌35 属,分隶于3 纲6 目10 科,其中以丛梗孢科占绝对优势, 有14 个属,占总属数的40.0 %;其次为暗梗孢科,有7 个属,占总属数的20.0 %.属的生态分布是:在7 个以上景点的空气中能够分离到的属有9 个, 其中芽枝霉属(Cladosporium)和无孢菌群(Mycelia Sterilia)在不同海拔的所有景点空气中普遍存在;海拔800 m 左右的空气中分离到的属较多,海拔高于1000m 的采样点分离到的属较少, 原因可能是随海拔降低, 气候变得温暖, 加上降雨量充沛,原生和次生常绿阔叶林发育良好, 大量枯落物归还土壤, 成为多种真菌丰富的营养来源, 故空气中分离到真菌的属较丰富, 数量也较多. 相似文献
162.
丙酮丁醇发酵菌的分子遗传改造 总被引:1,自引:0,他引:1
丙酮丁醇梭菌及拜氏梭菌是重要的ABE(丙酮、丁醇和乙醇)工业生产菌株,其发酵产物中的丙酮和丁醇均为重要的化工原料,汽车发动机试验证明丁醇还是一种性能优于乙醇的极具潜力的生物燃料和燃料添加剂。随着新生物技术的不断发展及工业生产的需求,遗传工程改造不断应用于丙酮丁醇生产菌株。在前人研究及工业实践的基础上,对丙酮丁醇生产菌株的遗传特性及其分子遗传改造取得的进展进行了详细概述。 相似文献
163.
可再生生物柴油副产物合成生物材料PHA研究现状 总被引:2,自引:0,他引:2
随着生物柴油产业的快速发展,大量的生物柴油副产物必将给生态环境及经济发展带来严重影响。如何利用新思路、新工艺、新技术加工处理副产物,将成为制约生物柴油产业发展的主要因素。聚羟基饱和脂肪酸酯(PHA)是当今生物材料领域最为活跃的研究热点,具有广泛的应用前景,但其生产成本高,选择便宜的合成原料一直是从事PHA研究的科学家们考虑的主要问题之一。将生物柴油副产物用于PHA生产研究,有助于解决副产物过度积累和PHA合成原料成本过高的问题,有利于生物柴油产业的稳定、可持续发展。本文综述了近年来生物柴油副产物用于PHA合成的最新进展。 相似文献
164.
165.
DA‐WEI ZHANG FEI XU ZHONG‐WEI ZHANG YANG‐ER CHEN JUN‐BO DU SHU‐DAN JIA SHU YUAN HONG‐HUI LIN 《Plant, cell & environment》2010,33(12):2121-2131
Mitochondrial alternative oxidase (AOX), the unique respiratory terminal oxidase in plants, catalyzes the energy wasteful cyanide (CN)‐resistant respiration and plays a role in optimizing photosynthesis. Although it has been demonstrated that leaf AOX is upregulated after illumination, the in vivo mechanism of AOX upregulation by light and its physiological significance are still unknown. In this report, red light and blue light‐induced AOX (especially AOX1a) expressions were characterized. Phytochromes, phototropins and cryptochromes, all these photoreceptors mediate the light‐response of AOX1a gene. When aox1a mutant seedlings were grown under a high‐light (HL) condition, photobleaching was more evident in the mutant than the wild‐type plants. More reactive oxygen species (ROS) accumulation and inefficient dissipation of chloroplast reducing‐equivalents in aox1a mutant may account for its worse adaptation to HL stress. When etiolated seedlings were exposed to illumination for 4 h, chlorophyll accumulation was largely delayed in aox1a plants. We first suggest that more reduction of the photosynthetic electron transport chain and more accumulation of reducing‐equivalents in the mutant during de‐etiolation might be the main reasons. 相似文献
166.
In flying insects, there is frequently a lack of congruence between empirical estimates of local demographic parameters and the prediction that differentiation between populations should decrease with increasing dispersal, a puzzling phenomenon known as Slatkin’s Paradox. Here, we generalize Slatkin’s Paradox to other taxa, drawing from available information on dispersal to predict the relative importance of pollen vs. seed migration in structuring broad‐scale patterns of genetic variation in Ficus hirta, a dioecious fig whose pollen is dispersed by minute, species‐specific fig wasps and whose seeds are disseminated by a variety of vagile vertebrates (especially bats and birds). Local‐scale observational and genetic studies of dioecious understory figs suggest comparable rates of pollen and seed migration. In contrast, we found unusually low nuclear differentiation (FST = 0.037, RST = 0.074) and high chloroplast differentiation (GST = 0.729, NST = 0.798) among populations separated by up to 2850 km, leading us to reject the hypothesis of equal pollen and seed migration rates and to obtain an equilibrium estimate of the ratio of pollen to seed migration of r = 16.2–36.3. We reconcile this example of Slatkin’s Paradox with previously published data for dioecious figs and relate it to the picture of exceptionally long‐distance wasp‐mediated pollen dispersal that is emerging for large monoecious fig trees. More generally, we argue that Slatkin’s Paradox is a general phenomenon and suggest it may be common in plants and animals. 相似文献
167.
DONG‐RU ZHANG MING‐YONG CHEN ROBERT W. MURPHY JING CHE JUN‐FENG PANG JIAN‐SHENG HU JING LUO SHAN‐JIN WU HUI YE YA‐PING ZHANG 《Molecular ecology》2010,19(16):3406-3420
Historical drainage patterns adjacent to the Qinghai‐Tibetan Plateau differed markedly from those of today. We examined the relationship between drainage history and geographic patterns of genetic variation in the Yunnan spiny frog, Nanorana yunnanensis, using approximately 981 base pairs of mitochondrial DNA partial sequences from protein‐coding genes ND1 and ND2, and intervening areas including complete tRNAIle, tRNAGln and tRNAMet. Two null hypotheses were tested: (i) that genetic patterns do not correspond to the development of drainage systems and (ii) that populations had been stable and not experienced population expansion, bottlenecking and selection. Genealogical analyses identified three, major, well‐supported maternal lineages, each of which had two sublineages. These divergent lineages were completely concordant with six geographical regions. Genetic structure and divergence were strongly congruent with historical rather than contemporary drainage patterns. Most lineages and sublineages were formed via population fragmentation during the rearrangement of paleodrainage basins in the Early Pliocene and Early Pleistocene. Sympatric lineages occurred only in localities at the boundaries of major drainages, likely reflecting secondary contact of previously allopatric populations. Extensive population expansion probably occurred early in the Middle Pleistocene accompanying dramatic climatic oscillations. 相似文献
168.
169.
小麦低分子量麦谷蛋白亚基分离条件优化 总被引:1,自引:0,他引:1
目的:优化一种有效分离小麦LMW-GS的实验条件。方法:以面包小麦L88-6作为材料,采用SDS-PAGE技术,通过对麦谷蛋白提取液、分离胶浓度、分离时间、电泳缓冲液等条件进行实验比较。结果与结论:含0.3mol/LNaI和1.4%4-VP的麦谷蛋白提取液能有效提取LMW-GS成分,分离胶浓度为T=14%C=3%、分离时间为40h、Tris-硼酸或Tris-甘氨酸电极缓冲液的分离条件分离效果好、重复性好、简单易行,为小麦低分子量麦谷蛋白亚基深入研究的第一个限速步骤提供了良好的解决方案。 相似文献
170.
以‘辽河4号'脱皮鲜食核桃果实为试材,经60Co γ射线辐照处理和聚乙烯(PE)保鲜袋包装后贮藏于(25±3)℃和(20±3)℃条件下,测定了相关生理指标的变化,探究60Co γ射线辐照对鲜食核桃萌芽生理的影响.结果表明,在(25±3)℃和(20±3)℃的贮藏条件下,对照组鲜食核桃分别在贮藏12和20 d 时开始发芽,处理组核桃在贮藏期间未出现发芽现象;在对照组鲜食核桃胚芽萌发期间,其呼吸强度、可溶性蛋白质和游离氨基酸含量及脂氧合酶(LOX)、过氧化氢酶(CAT)、过氧化物酶(POD)活性总体呈上升趋势,脂肪含量和脂肪酶(LPS)活性则降低; 而60Co γ射线辐照有效地减缓了鲜食核桃脂肪、可溶性蛋白质及游离氨基酸含量的下降速度及其呼吸代谢强度,提高了POD活性,却抑制了LOX、LPS、超氧化物歧化酶(SOD)和CAT的活性,从而阻碍了其胚芽的萌发,以达到延长其贮藏期的目的. 相似文献