早期人胚胎cDNA文库构建及目的基因筛选

收集受精后３、４和５周龄药物流产胚胎,用改良一步法提取总ＲＮＡ,ｏｌｉｇｏ（ｄＴ）纤维素柱纯化ｍＲＮＡ,逆转录合成一链ｃＤＮＡ,完成二链ｃＤＮＡ的合成后,经碱变性电泳检测,合成ｃＤＮＡ的大小为０．４～９．０ｋｂ之间,且主要集中在１．０～２．０ｋｂ。除去多余的接头,收集大于４００ｂｐ的ｃＤＮＡ片段,与载体ｐＳＰＯＲＴ１和和γＺｉｐＬｏｘ连接,分别得到３、４、５周龄人胚胎质粒文加和噬菌体文库。另外,采     

Genetic toolkits of the red alga Pyropia tenera against the three most common diseases in Pyropia farms

Disease outbreaks devastate Pyropia aquaculture farms every year. The three most common and serious diseases are Olpidiopsis‐blight and red‐rot disease caused by oomycete pathogens and green‐spot disease caused by the PyroV1 virus. We hypothesized that a basic genetic profile of molecular defenses will be revealed by comparing and analyzing the genetic response of Pyropia tenera against the above three pathogens. RNAs isolated from infected thalli were hybridized onto an oligochip containing 15,115 primers designed from P. tenera expressed sequence tags (EST)s. Microarray profiles of the three diseases were compared and interpreted together with histochemical observation. Massive amounts of reactive oxygen species accumulated in P. tenera cells exposed to oomycete pathogens. Heat shock genes and serine proteases were the most highly up‐regulated genes in all infection experiments. Genes involved in RNA metabolism, ribosomal proteins and antioxidant metabolism were also highly up‐regulated. Genetic profiles of P. tenera in response to pathogens were most similar between the two biotrophic pathogens, Olpidiopsis pyropiae and PyroV1 virus. A group of plant resistance genes were specifically regulated against each pathogen. Our results suggested that disease response in P. tenera consists of a general constitutive defense and a genetic toolkit against specific pathogens.     

Bacterial and fungal communities in bulk soil and rhizospheres of aluminum-tolerant and aluminum-sensitive maize (Zea mays L.) lines cultivated in unlimed and limed Cerrado soil

Liming of acidic soils can prevent aluminum toxicity and improve crop production. Some maize lines show aluminum (Al) tolerance, and exudation of organic acids by roots has been considered to represent an important mechanism involved in the tolerance. However, there is no information about the impact of liming on the structures of bacterial and fungal communities in Cerrado soil, nor if there are differences between the microbial communities from the rhizospheres of Al-tolerant and Al-sensitive maize lines. This study evaluated the effects of liming on the structure of bacterial and fungal communities in bulk soil and rhizospheres of Al-sensitive and Al-tolerant maize (Zea mays L.) lines cultivated in Cerrado soil by PCR-DGGE, 30 and 90 days after sowing. Bacterial fingerprints revealed that the bacterial communities from rhizospheres were more affected by aluminum stress in soil than by the maize line (Al-sensitive or Al-tolerant). Differences in bacterial communities were also observed over time (30 and 90 days after sowing), and these occurred mainly in the Actinobacteria. Conversely, fungal communities from the rhizosphere were weakly affected either by liming or by the rhizosphere, as observed from the DGGE profiles. Furthermore, only a few differences were observed in the DGGE profiles of the fungal populations during plant development when compared with bacterial communities. Cloning and sequencing of 16S rRNA gene fragments obtained from dominant DGGE bands detected in the bacterial profiles of the Cerrado bulk soil revealed that Actinomycetales and Rhizobiales were among the dominant ribotypes.     

Effects of an electric pulse on variation of bacterial community and metabolite production in kimchi-making culture

Three, six, nine, and twelve V of electric pulse (EP) was applied to a culture of Weissella cibaria SKkimchi1 in MRS medium and kimchi-making culture (KMC). Viable cell number of SKkimchi1 in MRS medium was decreased in proportion to pulse intensity but that of bacteria in KMC was not. Lactic acid and ethanol produced by SKkimchi1 tended to be decreased in proportion to EP intensity but acetic acid was proportionally increased to EP intensity. Lactic acid, ethanol, and propionic acid produced in KMC were proportionally decreased, but acetic acid was proportionally increased to the EP intensity. Bacterial community and diversity in KMC were analyzed based on culture time by a temperature gradient gel electrophoresis (TGGE) technique. Most bacterial communities grown in freshly prepared kimchi belonged to Bacillus genus. Lactic acid bacteria responsible for kimchi fermentation began to grow on day 4, and were completely substituted for Bacillus genus on day 8, but some Bacillus genus began to grow again on day 12. However, bacterial community diversities were not different based on varying EP intensity.     

Structural and ecophysiological adaptations to forest gaps

To survive new microclimatic conditions of a forest gap environment, plant species must physiologically and structurally adjust. A morpho-anatomical, ultrastructural and ecophysiological study was performed at three different times in a forest gap that was created by illegal selective logging. The study followed the early successional Actinostemon verticillatus and the late-successional Metrodorea brevifolia, to elucidate the adaptive strategies of acclimation to gaps. Additionally, Schinus terebinthifolius was included in the study in order to test the plasticity of a pioneer species that grows on forest edges, where this species had higher values of leaf thickness, leaf mass area and succulence. M. brevifolia had succulent leaves, high leaf area and a thin cuticle. A. verticillatus presented the densest leaves and was the only species to show leaf morpho-anatomical plasticity. Ultrastructural and physiological differences were observed only in A. verticillatus and M. brevifolia leaves from the gap: increase in the stroma volume, oil droplets, plastoglobuli, photochemical and non-photochemical quenching. Photosynthetic efficiency showed that the early stages of gap formation are the most critical. Acclimation strategies of A. verticillatus suggest this species invests in the efficiency of photosynthesis by increasing its leaf thickness, leaf mass area and in water content maintenance by increasing the density of its leaves, at the expense of gas exchange, was compensated by a high density of stomata. M. brevifolia compensates for the higher cost of leaves and lower leaf plasticity with ultrastructural changes that are used to adjust the photosynthetic process, which promotes a shorter leaf payback time.     

苹果叶片组培再生系统研究进展

几十年来 ,苹果叶片培养再生技术取得了较大的进展。叶片再生主要有器官发生和胚状体发生两种途径。影响叶片再生的主要因素有基因型、培养基、叶片发育阶段及生理年龄、暗培养等。就近年来国内、外学者在此方面的研究进展、存在问题及前景作简要概述。