园区网络的构建及安全管理

计算机网络的建设与安全在园区网络的构建过程中是相互紧密联系的两个方面,如何处理这两方面的关系,对网络的安全运行起着至关重要的作用。

银鲫ZP3的表达特征和卵壳ZP3蛋白的分离

克隆得到银鲫(Carassius auratus gibelio)ZP3基因全长cDNA,在体外表达出银鲫的ZP3融合蛋白,并制备出多抗血清;通过免疫印迹和RT-PCR分析,研究了银鲫ZP3在卵子发生过程中的表达特征和在早期发育胚胎中的状态变化。研究结果表明,银鲫ZP3的转录发生在卵黄发生以前,而ZP3蛋白的翻译起始于卵黄形成阶段,且随着卵母细胞进一步成熟,其含量不断增加。ZP3蛋白的存在状态在受精后和早期胚胎发育过程中发生了明显变化。在受精后5—30min期间,抽提液中原始的ZP3蛋白带迅速消失,取而代

城市湖泊地区的土地利用变化——以武汉东湖为例

利用1986、1993、1999年的LandsatTM卫星遥感影像和1981年地形图,借助GIS技术分析了城市湖泊地区—武汉东湖流域1987～1999间土地利用的时空变化及景观结构的变化。土地利用分为水体、针叶林、阔叶林、灌草、裸地、农业用地和城镇用地七种类型。各时期遥感影像分类精度都在85%以上。该流域土地利用变化以城镇大幅度扩展(从占全流域面积的9.1%到29.6%)、农业用地增加(从7.0%到13.9%)和由此引起的林地(从占全流域面积的33.6%到24.3%)、水体(从30.4%到23.8%)面积

车轮虫齿体特征的量化及其种内种间系统发育的研究

齿体特征是车轮虫物种鉴定的一个重要依据。本文首次提出一种齿体结构面积比例量化法 ,即通过对齿钩、齿锥、齿棘、齿体环各部分反口面观面积的测量 ,分别计算出前三者与所在齿体的面积比以及所有齿体总面积与齿体环的面积比 ,从而将齿体特征转换为量化指标。依据所测量化值 ,采用相似性聚类法 ,我们首先探讨了显著车轮虫 (TrichodinanobbillisChen ,196 3)的三个种群的亲缘关系 ,然后以劳牧小车轮虫 (TrichodinellalomiXu ,Song&Warren ,1999)为外类群 ,选

河鲈锚首吸虫及其宿主鳜鱼组织器官中铅含量的比较

利用原子吸收分光光度计分析了寄生鳜鱼（Sinipercachuatsi）鳃部的河鲈锚首吸虫（Ancyrocephalusmogurndae）及其宿主组织器官，包括肌肉、鳃、头肾和肝脏的铅含量.结果表明，来自三湖连江水库和牛山湖两个采样点的河鲈锚首吸虫的铅含量都显著地高于其宿主组织器官中的铅含量.在所检测的宿主组织器官中，肝脏的铅含量最高，在两个采样点分别为0.138和0.114μg/g（湿重）.河鲈锚首吸虫富集铅的机理及其较高水平铅含量的特点是否与其体外寄生的特性有关，尚有待于进一步研究.

蓝藻的一种人工转化系统研究

本研究用溶菌酶处理ＳｙｎｅｃｈｏｃｏｃｃｕｓＰＣＣ６３０１细胞诱导人工感受态，并用外源质粒ｐＢＲ３２５转化受体细胞表达氯霉素抗性，转化频率接近５×１０￣（－５）转化子／细胞。用转化子ＤＮＡ再进行次级转化，转化频率可达５×１０￣（－４）转化子／细胞。这比以前的研究者对同种藻株，用克隆的ＤＮＡ、通过生理感受态进行转化得到的转化频率要高。ＤＮＡ电泳、次级转化和斑点杂交证明外源质粒通过单交换已经整合到了受体细胞染色体上。这些结果表明，人工转化系统是有效的，并具有可重复性。对于影响转化的一些条件，如ＤＮＡ与细胞保温

异育银鲫对鱼粉等11种饲料中磷的利用率

于1988年,以三氧化二铬间接指示法,在水温22±2℃条件下,测定了平均体重为55±5g/尾的异育银鲫对鱼粉、肉骨粉、芝麻饼、虾粉、骨粉、菜籽饼、玉米粉、脱氟磷酸氢钙、磷酸二氢钙、磷酸氢钙、磷酸钙的表观消化吸收率。结果表明:异育银鲫对第一、第二、第三磷酸钙的消化吸收率是不同的,分别为81％,65％和32％,此顺序与其溶解性由大到小的顺序一致;在所测试的八种商品饲料中,对骨粉、虾粉和菜籽饼中磷的表观消化吸收率较高,分别为65％,68％和65％;对鱼粉、芝麻饼、肉骨粉三种原料中磷的表观消化吸收率较低,分别是1

丝藻目的一新属——骈丝藻属

<正> 1976年6月至8月,中国科学院青藏高原综合科学考察队藏北分队对冈底斯山,念青唐古拉山以北,昆仑山以南的广大藏北地区进行了多学科的综合考察。我所陈宜瑜同志参加了这次考察,对该地区各种水体的水生生物进行了广泛地采集,在采得的标本中,藻类是十分丰富的。我们在鉴定该区振泉湖藻类标本时,发现一特殊类型的藻类。通过对液浸标本和固定染色标本的研究,确定它是绿藻门丝藻目的一新属。

Investigations into the perplexing interrelationship of the Genus Takifugu Abe, 1949 (Tetraodontiformes, Tetraodontidae)

The phylogenetic relationships within the genus Takifugu Abe, 1949 (Tetraodontiformes, Tetraodontidae) remain unresolved. Because of the use of Takifugu as model organisms, the resolution of these relationships is crucial for the interpretation of evolutionary trends in biology. Pufferfishes of this genus are comprised of a comparatively small number of species and are mainly distributed along the coastal region of the western part of the Sea of Japan and the coastline of China. Mitochondrial gene sequences were employed to test the phylogenetic hypotheses within the genus. Seventeen species of the genus were examined. Molecular phylogenetic trees were constructed using the maximum parsimony, neighbor-joining, maximum likelihood and Bayesian methods. Our hypothesis of internal relationships within the genus differs from previous hypotheses. Our results indicate that (1) the genus Takifugu is a monophyletic assemblage; (2) the genus is divided into 6 subgroups based on the molecular data; and (3) there is low genetic diversity among the species within this genus. In addition, speciation within Takifugu appears to be driven by hybridization and isolation by distribution. Our results also suggested that the taxonomy in the genus should be clarified based on both molecular and morphological data.

Isolation and characterization of polymorphic microsatellites in a sex-reversal fish, rice field eel (Monopterus albus)

The rice field eel (Monopterus albus) is a fish of economic importance in China and some Asian countries. From a (GT)(n)-enriched genomic library, 30 microsatellites were developed by employing the fast isolation by AFLP of sequences containing repeats (FIASCO) protocol. Thirteen loci exhibited polymorphism with two to 13 alleles (mean 7.9 alleles/locus) in a test population and observed heterozygosity ranged from 0.3125 to 0.9688 (mean 0.7140). These loci should provide sufficient level of genetic variation to study the fine-scale population structure and reproductive ecology of the species.

Differential expression of vasa RNA and protein during spermatogenesis and oogenesis in the gibel carp (Carassius auratus gibelio), a bisexually and gynogenetically reproducing vertebrate

The RNA helicase Vasa is a germ cell marker in animals, and its homolog in vertebrates to date has been limited to bisexual reproduction. We cloned and characterized CagVasa, a Vasa homolog from the gibel carp, a fish that reproduces bisexually or gynogenetically. CagVasa possesses 14 RGG repeats and eight conserved motifs of Vasa proteins. In bisexually reproducing gibel carp, vasa is maternally supplied and its zygotic expression is restricted to gonads. By in situ hybridization on testicular sections, vasa is low in spermatogonia, high in primary spermatocytes, reduced in secondary spermatocytes, but disappears in spermatids and sperm. In contrast, vasa persists throughout oogenesis, displaying low-high-low levels from oogonia over vitellogenic oocytes to maturing oocytes. A rabbit anti-Vasa antibody (alpha Vasa) was raised against the N-terminal CagVasa for fluorescent immunohistochemistry. On testicular sections, Vasa is the highest in spermatogonia, reduced in spermatocytes, low in spermatids, and absent in sperm. In the ovary, Vasa is the highest in oogonia but persists throughout oogenesis. Subcellular localization of vasa and its protein changes dynamically during oogenesis. The aVasa stains putative primordial germ cells in gibel carp fry. It detects gonadal germ cells also in several other teleosts. Therefore, Cagvasa encodes a Vasa ortholog that is differentially expressed in the testis and ovary. Interestingly, the alpha Vasa in combination with a nuclear dye can differentiate critical stages of spermatogenesis and oogenesis in fish. The cross-reactivity and the ability to stain stage-specific germ cells make this antibody a useful tool to identify fish germ cell development and differentiation. (c) 2005 Wiley-Liss, Inc.

Distribution of the macroinvertebrate communities in the Xiangxi River system and relationships with environmental factors

Surveys of macroinvertebrates were carried out in the Xiangxi River system during July of 2001. Among the 121 taxa collected, Ephemeroptera, Trichoptera, and Diptera dominated (41.7, 26.0, and 24.5% of the total relative abundance, respectively). Two-way indictor species analysis and detrended correspondence analysis divided the 49 sites into four groups based on species composition and relative abundance. Canonical correspondence analysis indicated that elevation, SiO2, pH, conductivity, hardness, and NO2-N were significant environmental factors affecting the distribution of macroinvertebrates.

Molecular and expression characterization of three gonadotropin subunits common alpha, FSH beta and LH beta in groupers

A SMART cDNA plasmid library was constructed from protogyous greasy grouper (Epinephelus coioides) pituitary, and the full-length cDNAs of three gonadotropin (GTH) subunits common alpha, FSH beta and LH beta were cloned and sequenced from the library. The nucleotide sequences of common alpha, FSH beta and LH beta subunit cDNAs are 647, 594 and 574 bp in length, and encode for mature peptides of 94, 99 and 115 aa, respectively. High homology was observed by amino acid sequence alignment and identity comparison of the grouper mature peptides of common alpha, FSH beta and LH beta with that of other fishes. Phylogenetic tree analyses of the three GTH mature subunits revealed similar phylogeny relationships among the studied fish species. Three polyclonal antibodies were prepared from the in vitro expressed common alpha, FSH beta and LH beta mature proteins, respectively. Western blot analysis and immunofluoresence localization were performed on two typical stages of ovarian development stages in red-spotted grouper. Significant differences in protein expression levels of three gonadotropin subunits were revealed between the two ovarian development stages. In the individuals with resting ovary, common alpha was almost not detected in pituitaries, and FSH beta and LH beta expression levels were very low. While in the individuals with developing ovary, the expression of all three gonadotropin subunits reached to a high level. Immunofluoresence localization indicated that the grouper FSH beta cells mainly distributed in the middle area of PPD, while the LH beta cells distributed more widely, including in the area similar to the FSH beta cells and at the external periphery of pituitary near to the PI side. The common alpha might be expressed in both FSH beta and LH beta cells. Double immunofluoresence localization further demonstrated FSH beta and LH beta expression in distinct cells in the PPD area, although the FSH beta and LH beta cells were detected in the identical area of PPD. (c) 2005 Elsevier Ireland Ltd. All rights reserved.