The implications for aquaculture practice of epigenomic programming of components of the endocrine system of teleostean embryos: lessons learned from mammalian studies

Epigenetics is the study of changes in gene expression patterns that occur without any modification of the underlying nucleotide sequence of the DNA. Modifications of the so‐called epigenome include complex transient or permanent chemical changes of the DNA or histone proteins resulting in the suppression or enhancement of gene expression, together with an array of post‐translational events that modify the translational products. Epigenomic programming (EP) of the genome is an essential component of embryonic development in animals from the totipotent fertilized egg to the pluripotent stem cells, stem cell differentiation and final tissue and organ formation. Many of these EP processes are influenced transiently and some permanently by environmental influences. In eutherian mammals, environmentally related EP of embryos is linked to permanent changes in the phenotype of the progeny, some of which have been associated with adult onset metabolic disorders. Moreover, because some of the epigenetic remodelling occurs in both the soma and germ line, the resultant phenotypic characteristics (some of which are linked to disease states) may be heritable. Although far less is known about the effects of environmentally linked EP on the ontogeny of fishes, the available information suggests that the EP processes are similar amongst all vertebrates, and there are clear parallels between fish and mammals that are discussed in this paper. Our perspective takes the well‐established findings in mammals and uses them to proactively extrapolate to the as yet under‐recognized implications of EP for fish biology and for fish production in intensive aquaculture.     

巴西橡胶树花药体细胞胚形成中乳管分化的研究

培育数量多、质量好的体细胞胚是当前巴西橡胶树花药组织培养的主要研究目标,而对于体细胞胚发育过程中是否有乳管分化目前尚不清楚。以不同发育阶段的正常体细胞胚以及不同形态的畸形胚为材料,对它们的乳管分化情况进行了研究。结果表明,球形胚、心形胚和鱼雷胚中都没有乳管分化,最早出现可辨识的乳管是早期子叶胚,而不同形态的畸形胚都有乳管分化。本研究为深入研究乳管分化的机制提供了基础。     

落叶松体细胞胚胎发生过程中DNA甲基化模式变化分析

通过MSAP技术检测落叶松体细胞胚胎发生过程中的DNA甲基化模式变化发现,体细胞胚胎发生的14个时期中,5'-CCGG-3'序列的胞嘧啶上发生重新甲基化事件最多在ABA诱导后的0.5～6h,最少在5～7d的早期单胚阶段;而去甲基化事件发生最多的是5～7d的早期单胚阶段,最少在14～21d的中期单胚到晚期单胚阶段.与原胚...     

龙眼体细胞胚发生中期的蛋白质组学研究

 【目的】了解龙眼体细胞胚发生中期（球形胚至子叶形胚）蛋白质组的变化,为进一步阐明植物体细胞胚发生的机制提供依据。【方法】进行龙眼体细胞胚发生中期的同步化调控,采用双向电泳和质谱对龙眼体细胞胚发生中期的蛋白质组变化进行分析。【结果】龙眼体细胞胚发生中期表达蛋白的种类随着体细胞胚的发育逐渐减少,但在鱼雷形胚阶段其种类数量有所回升,且增加的蛋白分子质量小于66.0 kD,pI主要集中在5.00—7.00。成功鉴定了35个差异蛋白,发现了多个与体细胞胚发生密切相关的蛋白。1/2以上的蛋白与代谢途径有关,多个蛋白与氧化胁迫有关。RAN2 和 GTPase ObgE在龙眼体细胞胚发生中期发生了活跃的变化。【结论】随着体细胞胚的发育,细胞不断分化,体细胞胚中表达的蛋白种类减少。氧化胁迫相关蛋白、RAN2 和 GTPase ObgE与龙眼体细胞胚发生的调控有关。     

五加科植物体细胞胚发生研究进展

为了给五加科植物体细胞胚发生体系的建立提供理论依据,推动五加科植物体细胞胚研究的开展,本研究总结了五加科植物体细胞胚发生方式、体细胞胚发生的影响因素（包括外植体类型、培养基类型、植物生长调节剂种类、渗透胁迫）、体细胞胚发生的生理生化及次生代谢的研究现状。提出今后研究重点在以下几方面：（1）进一步对五加科植物体细胞胚发生的影响因素研究。（2）利用体细胞胚发生方式对一些重要的五加科植物进行次生代谢物的提取、代谢途径基因调控等的研究。（3）对五加科体细胞胚发生机制的分子基础需进一步研究。     

玉米和胡萝卜的体胚发生与蛋白质表达

[目的]研究玉米和胡萝卜体胚发生中的生理生化变化,从而为调控其体胚发生过程提供依据。[方法]研究单子叶植物代表玉米和双子叶植物代表胡萝卜体胚发生的适合培养基,并利用电泳技术对其体胚发生过程中的可溶性蛋白进行比较。[结果]培养基MS＋6-BA1.0mg/L＋2,4-D0.2mg/L＋CH500mg/L较适于玉米愈伤组织的发生;培养基B5＋2,4-D0.2mg/L＋6-BA0.2mg/L较适于胡萝卜愈伤组织的发生。玉米愈伤组织中存在活跃的蛋白表达;而胡萝卜愈伤组织中的蛋白表达水平则比下胚轴对照明显下降。二者蛋白质表达的差异可能与物种差异有关。[结论]发现了单子叶植物和双子叶植物体胚发生中蛋白质表达的规律。     

玉米受精胚囊的离体胚胎发生及植株再生研究

以授粉后1 d的玉米胚囊为外植体,通过改进胚囊分离方法、优化培养基激素成分,开展玉米受精胚囊的体外培养研究,建立玉米受精胚囊的离体胚胎发生及植株再生体系。结果表明,胚囊外植体获得形态正常胚的比例、胚再生为植株的比例均大大提高。经离体培养,约20%的玉米受精胚囊可以获得完整植株,建立了玉米受精胚囊的离体胚胎发生及植株再生体系。     

木薯体细胞胚发生过程中抗氧化酶活性变化

以木薯成熟体胚的子叶胚为外植物诱导的体细胞胚为材料,研究其体细胞胚发生过程中抗氧化酶活性(SOD,POD,CAT活性)和过氧化物酶同工酶酶谱的变化。结果表明,木薯体细胞胚发生过程中,SOD活性均在胚性细胞向球形胚转化时下降,鱼雷形胚和子叶形胚发育时升高;而POD和CAT活性呈相反趋势。初步认为,SOD酶活性降低可作为木薯胚性细胞初期分化和胚胎早期发育的一个判断指标。在木薯胚性细胞发生到分化和成熟过程中,过氧化物酶同工酶谱带由5条上升为9条,其中有5种过氧化物酶同工酶稳定出现,这可能是维持细胞基础代谢的一些基因表达的产物。     

Adverse effect of the chitinolytic enzyme PjCHI‐1 in transgenic tomato on egg mass production and embryonic development of Meloidogyne incognita

A novel chitinase gene (PjCHI‐1) isolated from Paecilomyces javanicus, a non‐nematophagous fungus, and driven by a CaMV35S promoter, was delivered into CLN2468D, a heat‐tolerant cultivar of tomato (Solanum lycopersicum). T₁ tomato plants exhibited high endochitinase activity and reduced numbers of eggs and egg masses when infected with the root‐knot nematode (RKN) Meloidogyne incognita. The eggs found in transgenic tomato had lower shell chitin contents than eggs collected from control plants. Egg masses from transgenic plants exhibited higher chitinase activity than those from control plants. Moreover, only 30% of eggs from transgenic plants were able to develop to the multi‐cell/J1 stage, compared with more than 96% from control plants. The present study demonstrated that the expression of the PjCHI‐1 chitinase gene can effectively reduce the production of egg masses and repress the embryonic development of M. incognita, presenting the possibility of a novel agro‐biotechnological strategy for preventing crop damage by RKN.     

A Review on Regeneration in Cowpea （Vigna unguiculata L. Walp）

Vigna unguiculata L. Walp is a recalcitrant plant in terms of in vitro cell, tissue and organ differentiation, which makes it difficult to apply tissue-culture dependant approaches for obtaining stable genetic transformation in cowpea. Despite this, sporadic efforts have been made to develop regeneration systems in cowpea during the past 40 years. This review presents the considerable progress on cowpea regeneration （organogenesis and embryogenesis） and especially focuses on the regeneration mode of organogenesis, including highlights of the effect of genotypes, explants, medium and plant hormones used in tissue culture. The existing problems and the future research directions were also discussed.