糖型与淀粉型木薯后代块根品质与发酵特性

为了研究糖型与淀粉型木薯后代块根品质与发酵特性,测定了28个木薯品系块根的干物质、淀粉、总糖、还原糖、粗蛋白和灰分等主要品质性状。结果表明,淀粉型木薯后代块根的淀粉(14.52%)、总糖(27.48%)、干物质(41.24%)、粗蛋白(1.67%)和灰分(0.25%)含量,总体上比糖型木薯后代块根高;糖型木薯后代块根还原糖含量(2.01%)显著高于淀粉型木薯后代块根(0.61%)(P<0.05),而其淀粉含量仅6.62%。相关分析表明,还原糖与淀粉、总糖、干物质和粗蛋白等性状均呈显著负相关(P<0.05)。通过杂交改良克服负相关,新品系SM03块根的乙醇转化率达到53.7 mL/100 g干质量,产酒精34.73 L/hm^2。SM03和SC16只糖化、不经过糊化预处理,酵母发酵分别产酒精31.13 L/hm2、27.80 L/hm^2,均是很有推广价值的能源木薯新品种。

铁基金属有机骨架材料制备工艺对其光催化性能的影响

以氯化铁和均苯三甲酸为原料,分别采用溶胶-凝胶法、恒温水浴法和水热法3种制备工艺合成了铁基金属有机骨架材料MIL-100(Fe)。通过X射线衍射(XRD)、红外光谱(FT-IR)、场发射扫描电镜(SEM)、固体紫外-可见吸收光谱(UV-Vis)、比表面积(BET)测试等方法对MIL-100(Fe)样品进行表征,讨论了3种制备工艺对MIL-100(Fe)样品晶相、形貌、结构的影响及其对罗丹明B光催化降解性能的影响。研究表明,高比表面积、强光吸收有利于MIL-100(Fe)吸附-催化性能的提高,水热法制备的MIL-100(Fe)较其他两种方法制备的样品具有更优异的净化性能。

Preliminarily study on the maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on gastropods

The present study preliminarily examined the differences in maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on four gastropods species( Bellamya aeruginosa, Radix auricularia, Parafossarulus sinensis and Alocinma longicornis) under laboratory conditions. In the maximum handling size trial, five fish from each age group(1-year-old and 2-year-old) and each genotype(transgenic and non-transgenic) of common carp were individually allowed to feed on B. aeruginosa with wide shell height range. The results showed that maximum handling size increased linearly with fish length, and there was no significant difference in maximum handling size between the two genotypes. In the size selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on three size groups of B. aeruginosa. The results show that the two genotypes of C. carpio favored the small-sized group over the large-sized group. In the species selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on thin-shelled B. aeruginosa and thick-shelled R. auricularia, and five pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on two gastropods species( P. sinensis and A. longicornis) with similar size and shell strength. The results showed that both genotypes preferred thin-shelled Radix auricularia rather than thick-shelled B. aeruginosa, but there were no significant difference in selectivity between the two genotypes when fed on P. sinensis and A. longicornis. The present study indicates that transgenic and non-transgenic C. carpio show similar selectivity of predation on the size-and species-limited gastropods. While this information may be useful for assessing the environmental risk of transgenic carp, it does not necessarily demonstrate that transgenic common carp might have lesser environmental impacts than non-transgenic carp.

我国科技期刊改革实践与思考——以《中国科学》系列和《科学通报》期刊为例

如何加快中国品牌的世界一流科技期刊建设,已经成为新时代科技期刊建设的重要研究课题。本文以《中国科学》系列和《科学通报》(以下简称为"两刊")为例,从优化期刊布局、推动学部平台办刊、发挥专家办刊作用、提升学术质量和核心竞争能力等方面介绍"两刊"的改革举措与发展实践,并从集群化、国际化、专业化和数字化4个方面对世界一流科技期刊建设提出思考与建议。

Molecular basis and genetic improvement of economically important traits in aquaculture animals

Aquaculture has been believed to be a major Chinese contribution to the world. In recent 20 years, genome and other genetic technologies have promoted significant advances in basic studies on molecular basis and genetic improvement of aquaculture animals, and complete genomes of some main aquaculture animals have been sequenced or announced to be sequenced since the beginning of this century. Here, we review some significant breakthrough progress of aquaculture genetic improvement technologies including genome technologies, somatic cell nuclear transfer and stem cell technologies, outline the molecular basis of several economically important traits including reproduction, sex, growth, disease resistance, cold tolerance and hypoxia tolerance, and present a series of candidate trait-related genes. Finally, some application cases of genetic improvement are introduced in aquaculture animals, especially in China, and several development trends are highlighted in the near future.

Progress in studies of fish reproductive development regulation

Mechanisms of the animal reproductive development are an important research field in life sciences.The study of the reproductive development and regulatory mechanisms in fishes is important for elucidating the mechanisms of animal reproduction.This paper summarizes recent advances in the mechanisms of fish sex determination and differentiation,of fish gonad development and maturation,and of fish germ cell development,as well as the according regulating strategies.Fishes comprise an evolutionary stage that links invertebrates and higher vertebrates.They include diversiform species,and almost all vertebrate types of reproduction have been found in fishes.All these will lead to important advances in the regulatory mechanisms of animal reproduction by using fishes as model organisms.It will also enable novel fish breeding techniques when new controllable on-off strategies of reproduction and/or sex in fishes have been developed.

Rapid growth and sterility of growth hormone gene transgenic triploid carp

Triploid carp(100%)with 150(3n=150)chromosomes were obtained by crossing the females of improved tetraploid hybrids(♀, 4n=200)of red crucian carp(♀)×common carp(♂)with the males of diploid yellow river carp(♂,2n=100).The crosses yielded transgenic triploid carp(positive triploid fish,44.2%of the progeny)and non-transgenic triploid carp(negative triploid fish). Histological examination of the gonads of 24-month-old positive triploid fish suggested they were sterile and the fish were not able to produce mature gametes during the breeding season.Morphologically,both the positive and negative triploid fish were similar.They had a spindle-shaped,laterally compressed,steel grey body with two pairs of barbells.Most of the quantifiable traits of the triploid carp were intermediate between those of the two parents.The positive and negative triploid fish were raised in the same pond for 2 years.The mean body weight of the positive triploid fish was 2.3 times higher than the negative triploid fish.The weight of the largest positive triploid fish was 2.91 times higher than that of the largest negative triploid fish.Thus,we produced fast-growing transgenic triploid carp that have a reduced ecological risk because of their inability to mate and produce progeny.

Rapid growth cost in “all-fish” growth hormone gene transgenic carp:Reduced critical swimming speed

Evidence has accumulated that there is a trade-off between benefits and costs associated with rapid growth. A trade-off between growth rates and critical swimming speed (Ucrit) had been also reported to be common in teleost fish. We hypothesize that growth acceleration in the F3 generation of "all-fish" growth hormone gene (GH) transgenic common carp (Cyprinus carpio L.) would reduce the swimming abilities. Growth and swimming performance between transgenic fish and non-transgenic controls were compared. The results showed that transgenic fish had a mean body weight 1.4―1.9-fold heavier,and a mean specific growth rate (SGR) value 6%―10% higher than the controls. Transgenic fish,however,had a mean absolute Ucrit (cm/s) value 22% or mean relative Ucrit (BL/s) value 24% lower than the controls. It suggested that fast-growing "all-fish" GH-transgenic carp were inferior swimmers. It is also supported that there was a trade-off between growth rates and swimming performance,i.e. faster-growing individuals had lower critical swimming speed.

Fish genome manipulation and directional breeding

Aquaculture is one of the fastest developing agricultural industries worldwide.One of the most important factors for sustainable aquaculture is the development of high performing culture strains.Genome manipulation offers a powerful method to achieve rapid and directional breeding in fish.We review the history of fish breeding methods based on classical genome manipulation,including polyploidy breeding and nuclear transfer.Then,we discuss the advances and applications of fish directional breeding based on transgenic technology and recently developed genome editing technologies.These methods offer increased efficiency,precision and predictability in genetic improvement over traditional methods.

Cloning and expression analysis in mature individuals of two chicken type-Ⅱ GnRH (cGnRH-Ⅱ) genes in common carp (Cyprinus carpio)

Gonadotropin-releasing hormone (GnRH) is a conservative neurodecapeptide fam-ily, which plays a crucial role in regulating the gonad development and in controlling the final sexual maturation in vertebrate. Two differing cGnRH-II cDNAs of common carp, namely cGnRH-II cDNA1 and cDNA2, were firstly cloned from the brain by rapid amplification of cDNA end (RACE) and reverse transcription- polymerase chain reaction (RT-PCR). The length of cGnRH-II cDNA1 and cDNA2 was 622 and 578 base pairs (bp), respectively. The cGnRH-II pre-cursors encoded by two cDNAs consisted of 86 amino acids, including a signal peptide, cGnRH-II decapeptide and a GnRH-associated peptide (GAP) linked by a Gly-Lys-Arg proteolytic site. The results of intron trapping and Southern blot showed that two differing cGnRH-II genes in common carp genome were further identified, and that two genes might exist as a single copy. The multi-gene coding of common carp cGnRH-II gene offered novel evidence for gene duplica-tion hypothesis. Using semi-quantitative RT-PCR, expression and relative expression levels of cGnRH-II genes were detected in five dissected brain regions, pituitary and gonad of common carp. With the exception of no mRNA2 in ovary, two cGnRH-II genes could be expressed in all the detected tissues. However, expression levels showed an apparent difference in different brain regions, pituitary and gonad. According to the expression characterization of cGnRH-II genes in brain areas, it was presumed that cGnRH-II might mainly work as the neurotransmitter and neuromodulator and also operate in the regulation for the GnRH releasing. Then, the ex-pression of cGnRH-II genes in pituitary and gonad suggested that cGnRH-II might act as the autocrine or paracrine regulator.

Acute and chronic un-ionized ammonia toxicity to ‘all-fish’ growth hormone transgenic common carp(Cyprinus carpio L.)

Ammonia is toxic to fish in natural and artificial waters.We evaluated the acute(96 h) and chronic(21 d) toxicity of un-ionized ammonia to GH transgenic common carp(Cyprinus carpio L.) and non-transgenic common carp using a static-renewal bioassay.The 24,48,72 and 96 h median lethal concentrations(LC50) of un-ionized ammonia were slightly lower in transgenic carp(2.64,2.44,2.28 and 2.16 mg N/L,respectively) than in non-transgenic carp(2.70,2.64,2.52 and 2.33 mg N/L,respectively).Similarly,the median lethal time(LT50) was significantly shorter for transgenic carp(1.41,7.91 and 117.42 h) than for non-transgenic common carp(2.53,14.06 and 150.44 h) following exposure to 3.86,3.29,or 2.09 mg N/L,respectively.Moreover,the mortality of transgenic carp was significantly higher than that of non-transgenic carp at all un-ionized ammonia concentrations((0.91 ± 0.12),(0.48 ± 0.06) and(0.12 ± 0.01) mg N/L) during the 21 d chronic toxicity test.Our results suggest that GH transgenic carp are less tolerant of unionized ammonia than non-transgenic carp.Our data are useful for evaluating potential environmental risk,optimizing stocking density in intensive aquaculture and establishing water quality criteria for ammonia in aquaculture.

Transgene for growth hormone in common carp(Cyprinus carpio L.)promotes thymus development

The transgenic carp were produced by micro-injection of CAgcGHc into the fertilized eggs. Observation of the thymus development between the transgenics and non- transgenic controls was carried out. The thymus of one-year- old transgenics F1 showed a great increase in both size and weight. The unilateral thymus of the transgenics weighed from 190 to 295 mg with average 218.6 mg, whereas the uni-lateral thymus of the controls weighed 20—81 mg with av-erage 42.5 mg; i.e. the thymus weight in the transgenics was 5.14 fold over that in the controls. The index of thymus/body weight in the transgenics was 2.97 fold over the controls. Light microscopy observation indicated that the thymus of the transgenics well developed with the thickened outer re-gion and compactly arranged thymocytes, while the thymus in the controls were degenerating with the thinned outer region, scattered thymocytes and groups of fatty cells. Fur-ther analysis with the electron microscopy revealed that pro-liferous cells in the transgenics were mainly small lympho-cytes and no pathological changes were found. The results confirmed that the 揂ll-fish?GH-transgene promotes thy-mus development and thymocyte proliferation, and retards thymus degeneration. The study has laid a foundation for further analysis of the immunobiological function in GH- transgenic carp.

Male non-coding RNA genes identified by comparative genomic analysis of the Drosophila genomes

这个问题由杨等出版了一篇研究文章。北京大学“在在果蝇的密切相关的种类之中的性相关的非编码的 RNA 表示模式的重要分叉”。在 D 的 genomic 分析。melanogaster 和它的近亲， D.simulans， D。yakuba 和另外的相关种类， D。pseudoobscura 和 D。virillis，杨 et al.identified 一打性腺 --( 主要睾丸 --) 表示非编码的 RNA (ncRNA ) 基因。这些 ncRNA 基因在这些显示出分叉的表示模式，这被揭示种类。在学习使用的简单方法能高效地从大量有机体在一组密切相关的种被用于 ncRNA 基因的察觉。这个评价不在这篇论文详细重申实验和解释。相反，我们将在生物学的理解和性复制的进化在相关结果的意义的讨论提出我们的强调。我们将在 ncRNA 基因的区域的开发和教育讨论这个工作的一般意义。

Enzyme-linked immunosorbent assay of changes in serum levels of growth hormone(cGH)in common carps(Cyprinus carpio)

The aim of the present study was to purify the common native carp growth hormone (ncGH), produce monoclonal antibodies (mAbs) to common native carp growth hormone (ncGH), and further enhance the sensitivity of enzyme-linked immunosorbent assays (ELISA) for ncGH. Additionally, we investigated changes in serum ncGH levels in carps raised in different environmental conditions. The recombinant grass carp (Ctenopharyngodon idella) growth hormone was purified and used as antigen to immunize the rabbit. The natural ncGH was isolated from the pituitaries of common carp. SDS-PAGE and Western blot utilizing the polyclonal anti-rgcGH antibody confirmed the purification of ncGH from pituitaries. Purified ncGH was then used as an immunogen in the B lymphocyte hybridoma technique. A total of 14 hybridoma cell lines (FMU-cGH 1-14) were established that were able to stably secrete mAbs against ncGH. Among them, eight clones (FMU-cGH1-6, 12 and 13) were successfully used for Western blot while nine clones (FMU-cGH 1-7, 9 and 10) were used in fluorescent staining and immunohistochemistry. Epitope mapping by competitive ELISA demonstrated that these mAbs recognized five different epitopes. A sensitive sandwich ELISA for detection of ncGH was developed using FMU-cGH12 as the coating mAb and FMU-cGH6 as the enzyme labeled mAb. This detection system was found to be highly stable and sensitive, with detection levels of 70 pg/mL. Additionally, we found that serum ncGH levels in restricted food group and in the net cage group increased 6.9-and 5.8-fold, respectively, when compared to controls, demonstrating differences in the GH stress response in common carp under different living conditions.

Celebrating 90 years of Peking University School of Life Sciences(1925–2015)

The Department of Biology at Peking University was established in 1925,with Mr.Tan Xi Hong as its inaugural department head.In 1993,the department was renamed the School of Life Sciences.During the past 90 years,a steady stream of students has enrolled in the department in order to explore the secrets of life and to dedicate themselves to the advancement of society.