两种色型黄粉虫酚氧化酶原的cDNA克隆、生物信息学分析及表达水平检测

酚氧化酶是黑色素合成和昆虫免疫的关键酶, 通常以无活性的酚氧化酶原形式存在。为给黄粉虫Tenebrio molitor遗传分化和免疫防御研究提供参考, 本研究采用PCR和RACE技术克隆了黄、 黑两种色型黄粉虫幼虫的酚氧化酶原基因Tm-ppo, 对其cDNA序列及其推导的氨基酸序列进行生物信息学分析, 采用实时荧光定量PCR检测其在两种色型黄粉虫不同发育阶段mRNA表达水平上的动态变化。结果表明： 从黄、 黑两种色型黄粉虫幼虫中克隆出的两个Tm-ppo cDNA序列全长均为2 199 bp, 碱基序列一致性为99%, 包含一个2 055 bp的开放阅读框, 编码684个氨基酸, 它们的编码蛋白有3个氨基酸差异： 第176位（P→A）、 256位（V→A）和648位（I→M）。这两个基因分别被命名为Tm-ppo-1和Tm-ppo-2 （GenBank登录号分别为JX987235和JX987234）。 Tm-ppo-1和Tm-ppo-2编码的酚氧化酶原异构体蛋白（分别为Tm-PPO-1和Tm-PPO-2）存在一个可能的酚氧化酶原水解活化位点（R50~F51残基之间）和一个双铜结合中心（第196~239位残基和第344~411位残基）; 同时含有一个类似巯基酯区域的序列（第579~588位残基）及一个C 末端保守基序（第634~645位残基）; 但它们无氨基端疏水信号肽序列, 也不存在跨膜区域。Tm-PPO-1和Tm-PPO-2的二级结构由大量的α 螺旋、 β-折叠和无规则卷曲组成; 三级结构分为前导域（第16~66位残基）、 不相邻的功能域Ⅰ（第3~15位残基和第67~181位残基）、 功能域Ⅱ（第182~419位残基）和功能域Ⅲ（第420~679位残基）4部分。此外, Tm-ppo-1和Tm-ppo-2在黄、 黑两种色型黄粉虫的各发育期均有表达, 并且不同发育阶段的mRNA表达水平呈现明显的变化规律： 幼虫期﹥成虫期﹥蛹期。同时, 环境温度对Tm-ppo-1和Tm-ppo-2的mRNA表达具有显著影响： 与常温对照组（25~30℃）相比, 42℃暴露24 h和48 h的两种色型黄粉虫幼虫、 蛹和成虫的mRNA表达量明显下调。相同试验条件下, 黑色型黄粉虫幼虫和成虫的Tm-ppo-2 mRNA表达量明显高于黄色型幼虫和成虫的Tm-ppo-1 mRNA表达量, 但两种色型黄粉虫蛹的Tm-ppo异构体表达量无显著差异。本研究为进一步探讨黄粉虫的遗传分化和免疫防御提供了有益参考。     

A New Variety of Spergularia (Caryophyllaceae) from Zhejiang,China

Spergularia marina var. cleistogama, a new variety of Caryophyllaceae from Zhejiang Province, China is described and illustrated. It is similar to S.marina var. marina, but differs by having triangular ovate stipules, unequally width of sepals, and 0-4 petals, a few of which may change into stamens. It is also characterized by its cleistogamous flowers, pistils with 0.2-0.3mm long gynophores, 5-7 stamens, capsules wrapped with persistent calyxes, and ovate, flat seeds.     

CO2浓度升高对不同品种水稻镉吸收和根形态的影响

为了探讨CO2浓度升高下不同水稻品种荣优398 (RY)和粤杂889(YZ)吸收重金属Cd差异性的原因,利用水培试验研究了不同浓度Cd处理下两种水稻吸收Cd的差异及根形态的变化特征.结果表明:低Cd处理(5、10、20 μmol·L-1)显著增加水稻生物量;当Cd浓度高于50 μmol·L-1时,Cd胁迫效果开始显现,水稻生物量减少.CO2浓度升高显著增加了水稻的生物量,增加了YZ茎Cd含量而降低了RY茎Cd含量.在5～200 μmol·L-1的Cd浓度下,CO2浓度升高增加了YZ活性根在总根长中的比例,降低了RY活性根的比例.CO2浓度升高下不同水稻品种根形态的变化是导致其对Cd吸收差异性的原因之一.     

三株海洋木霉的应用潜力

【目的】探索3株海洋生境木霉的应用潜力。【方法】经过筛选和诱变,获得高抑菌活性及产孢量的木霉突变株;通过优化培养基、温度、初始p H考察其产孢量及最适培养条件;综合抑菌谱、重寄生及抑菌相关基因考察其抑菌活性;采用特殊培养基法考察其产纤维素酶、植酸酶、铁载体以及降解磷钾的能力,高效液相色谱法测定其产吲哚乙酸能力。【结果】3株木霉菌的产孢量分别为3.45×108、3.10×108和2.55×108 CFU/cm2,与野生型相比分别提高了88.52%、63.16%和180.22%;且均可产生厚垣孢子,其中XG20-1厚垣孢子产量最高,达到3.56×108 CFU/m L。3株木霉菌具有较广抑菌谱及对番茄早疫病菌的重寄生作用,同时扩增得到Tex1、Nag1、Eg1基因,生物学测试显示其均具有产纤维素酶、几丁质酶以及铁载体的能力,证明其抑菌活性是多种机制共同作用的结果;菌株可以降解磷钾,且吲哚乙酸产量分别为2.61、1.57和1.92 mg/L,具有促进植物生长的潜力。【结论】本文中3株木霉菌在开发为生防菌与生物肥料方面展现出良好的应用潜力。     

辽西北风沙地区不同无性系桑树抗旱性

为选育适合辽西北风沙地区生长的优良桑树品种,以沈阳农业大学选育的"沈桑1号"(SS)、辽宁省阜新市彰武县优株(ZW)、吉林省通化市集安县桑树优株(JS)3种优质桑树无性系以及东北主栽品种"龙桑1号"(LS)为试验材料,通过测定不同无性系桑树在干旱胁迫下的叶片光合色素含量、光响应曲线、不同光强对气体交换参数的影响以及光系...     

Primary identifications and palynological observations of Perilla in China

Unresolved controversies concerning classification of the monotypic genus Perilla L. have hindered the complete understanding and subsequent sustainable use of these vital food, oil and medicinal plants to their full potential. We attempted to use scanning electron microscopy to obtain palynological evidence from Perilla plants of 21 samples from seven provinces in China as a potential extra attribute in classification. The findings showed that pollen grains from plants of 11 samples were oblate, while those of the other 10 were suboblate in shape, and there were no any type of prolate pollen grains being observed. Pollen grains of all the samples had diverse exine ornamentations. Based on whether having continuous tecta on the ornamentations, all of the pollen grains derived from the 21 samples were classified into two categories, fourteen of them with irregular reticulates, seven with continuous tecta with no perforations. None of the samples were bireticulates. The ornamentation pattern and size of pollen grains jointly provided evidence that it is appropriate to classify the genus Perilla into five varieties of one species. Furthermore, by comparison, it is concluded that shapes and exine ornamentations of Perilla are unique among those of the seven genera already investigated in the subfamily Lamioideae. Using these pollen features, Perilla could be easily distinguished from two other subtribes (Menthinae Briq. and Thyminae Briq.) in the same tribe, supporting the view that Perilla and other four related genera were divided into one subtribe (Perillinae).     

我国土壤动物与土壤环境要素相互关系研究进展

土壤动物与土壤生态系统的环境要素密切相关,探明土壤动物与环境要素之间的相互关系对深刻认识土壤生态系统的运行机制、评价土壤生态系统功能具有重要意义.影响土壤动物的环境要素可以分为土壤性质和土壤外部环境两方面,前者主要指土壤基本理化性质、土壤水分和土壤污染状况,后者包括植被、土地利用、地貌和气候等环境要素.本文从以上角度对我国土壤动物与土壤环境要素关系研究进行总结和归纳,认为当前我国相关研究中主要存在以下若干问题：与环境指示作用整合性研究较少,研究方法有待改进,对环境要素的综合性及其时空变异性认识不足.并提出了相应的建议：与实际研究需要相结合,借鉴国外先进方法经验,进行多要素综合研究以及开展大区域长期监测等.     

Mnl2, a novel component of the ER associated protein degradation pathway

In eukaryotes, membrane and soluble proteins of the secretory pathway enter the endoplasmic reticulum (ER) after synthesis in an unfolded state. Directly after entry, most proteins are modified with glycans at suitable glycosylation sites and start to fold. A protein that cannot fold properly will be degraded in a process called ER associated degradation (ERAD). Failures in ERAD, either by loss of function or by premature degradation of proteins, are a cause of severe diseases. Therefore, the search for novel ERAD components to gain better insight in this process is of high importance. Carbohydrate trimming is a relevant process in ER quality control. In this work a novel putative yeast mannosidase encoded by the open reading frame YLR057W was identified and named Mnl2. Deletion of MNL2 diminished the degradation efficiency of misfolded CPY^* in the absence of the cognate mannosidase Mnl1, indicating a specific role in ERAD.     

A double-flowered variety of lesser periwinkle (Vinca minor fl. pl.) that has persisted in the wild for more than 160 years

Background and Aims

Homeotic transitions are usually dismissed by population geneticists as credible modes of evolution due to their assumed negative impact on fitness. However, several lines of evidence suggest that such changes in organ identity have played an important role during the origin and subsequent evolution of the angiosperm flower. Better understanding of the performance of wild populations of floral homeotic varieties should help to clarify the evolutionary potential of homeotic mutants. Wild populations of plants with changes in floral symmetry, or with reproductive organs replacing perianth organs or sepals replacing petals have already been documented. However, although double-flowered varieties are quite popular as ornamental and garden plants, they are rarely found in the wild and, if they are, usually occur only as rare mutant individuals, probably because of their low fitness relative to the wild-type. We therefore investigated a double-flowered variety of lesser periwinkle, Vinca minor flore pleno (fl. pl.), that is reported to have existed in the wild for at least 160 years. To assess the merits of this plant as a new model system for investigations on the evolutionary potential of double-flowered varieties we explored the morphological details and distribution of the mutant phenotype.

Methods

The floral morphology of the double-flowered variety and of a nearby population of wild-type plants was investigated by means of visual inspection and light microscopy of flowers, the latter involving dissected or sectioned floral organs.

Key Results

The double-flowered variety was found in several patches covering dozens of square metres in a forest within the city limits of Jena (Germany). It appears to produce fewer flowers than the wild-type, and its flowers are purple rather than blue. Most sepals in the first floral whorl resemble those in the wild-type, although occasionally one sepal is broadened and twisted. The structure of second-whorl petals is very similar to that of the wild-type, but their number per flower is more variable. The double-flowered character is due to partial or complete transformation of stamens in the third whorl into petaloid organs. Occasionally, ‘flowers within flowers’ also develop on elongated pedicels in the double-flowered variety.

Conclusions

The flowers of V. minor fl. pl. show meristic as well as homeotic changes, and occasionally other developmental abnormalities such as mis-shaped sepals or loss of floral determinacy. V. minor fl. pl. thus adds to a growing list of natural floral homeotic varieties that have established persistent populations in the wild. Our case study documents that even mutant varieties that have reproductive organs partially transformed into perianth organs can persist in the wild for centuries. This finding makes it at least conceivable that even double-flowered varieties have the potential to establish new evolutionary lineages, and hence may contribute to macroevolutionary transitions and cladogenesis.     

黄河三角洲盐碱地条件下不同甘薯品种耐盐性

利用北方薯区当前生产上广泛种植的甘薯新品种,在黄河三角洲盐碱地上开展种植试验,以期选育耐盐甘薯品种。对每个测试品种的重要农艺性状及盐离子含量进行分析。结果表明不同甘薯品种的耐盐性存在差异。除叶片数、分枝数、分枝长度无显著性差异外,其他农艺性状如总鲜重、鲜薯产量、薯块干率、薯干产量、薯块数等都在不同品种中达到显著水平,建议耐盐性的评价指标应以鲜薯和薯干产量为主。对甘薯新生叶片、成熟叶片、须根、块根等不同器官进行Cl-、Ca2＋、Na＋和K＋的含量分析,结果表明不同品种其不同器官中各种盐离子含量差异显著,暗示不同基因型耐盐机制存在差异。基于对鲜薯和薯干产量的比较,筛选出耐盐碱的品种,主要有‘泰中9号’、‘苏薯7号’、‘龙薯1号’、‘徐薯18’等。同时,对甘薯种植前后的土壤总盐分和营养成分的分析显示：甘薯收获后,土壤中的含盐量显著降低。本研究为沿海滩涂培育和种植耐盐碱甘薯新品种进行了有益的尝试,同时也为盐碱地改良和生物质能原材料种植提供了思路。