异源三倍体鲫鲂的遗传组成和生殖特性观察

红鲫属鲤亚科,其染色体数目为2n=100;团头鲂属于鲌亚科,其染色体数目为2n=48。在红鲫(♀)×团头鲂(♂)的远缘杂交F1代中获得了异源三倍体鲫鲂和异源四倍体鲫鲂。本研究对异源三倍体鲫鲂进行了染色体核型分析、染色体FISH杂交检测和性腺结构观察,结果表明:1)异源三倍体鲫鲂的染色体数目为3n=124,染色体核型公式为31m+45sm+26st+22t,染色体组由2套红鲫染色体和1套团头鲂染色体组成;2)利用红鲫特有重复序列为探针进行FISH杂交,红鲫的100条染色体均被标记上荧光信号,而团头鲂的染色体均未标记上荧光信号,异源三倍体鲫鲂中有100条染色体被标记上荧光信号,说明异源三倍体鲫鲂含有2套红鲫来源的染色体组;3)异源三倍体鲫鲂的性腺发育异常,其卵巢型和精巢型性腺发育呈现出退化的特征。研究还讨论了异源三倍体鲫鲂的形成机制。实验结果为鱼类远缘杂交和多倍体鱼研究提供了实验数据,在鱼类遗传育种方面具有重要意义。     

甘蓝2号染色体的高分辨率5S rDNA荧光原位杂交

 【目的】羽衣甘蓝5S rDNA 的染色体定位和拷贝数分析,为进一步利用FISH进行2号染色体基因定位和细胞遗传图谱构建奠定基础。【方法】以羽衣甘蓝为材料,采用荧光原位杂交技术将DIG标记的5S rDNA探针定位于不同分辨率的绒毡层细胞中期染色体、粗线期染色体以及伸长DNA纤维上。【结果】在中期染色体和粗线期染色体上,都同时获得3个杂交信号位点（a、b、c）,且位于2号染色体的长臂近着丝粒区域,其信号强度为b＞a＞c;而在伸长DNA纤维上,出现了3种不同长度的念珠状长链（a、b、c）, 其物理大小分别为257、359和134 kb,这3种长链分别与3个信号位点形成一一对应关系。【结论】在羽衣甘蓝2号染色体上存在3个串联重复位点,粗略估算出3个5S rDNA位点的拷贝数分别为510、712和266。     

FISH mapping of 10 canine BAC clones harbouring genes and microsatellites in the arctic fox and the Chinese raccoon dog genomes

Cytogenetic mapping of the arctic fox and the Chinese raccoon dog were performed using a set of canine probes derived from the Bacterial Artificial Chromosome (BAC) library. Altogether, 10 BAC clones containing sequences of selected genes (PAX3, HBB, ATP2A2, TECTA, PIT1, ABCA4, ESR2, TPH1, HTR2A, MAOA) and microsatellites were mapped by fluorescence in situ hybridization (FISH) experiments to chromosomes of the canids studied. At present, the cytogenetic map on the arctic fox and Chinese raccoon dog consists of 45 loci each. Chromosomal localization of the BAC clones was in agreement with data obtained by earlier independent comparative chromosome painting. However, two events of telomere‐to‐centromere inversions were tentatively identified while compared with assignments in the dog karyotype.     

Fertile male tortoiseshell cat with true chimerism 38,XY/38,XY

The tortoiseshell coat colour is characteristic to female cats, and its occurrence in tomcats is very rare and associated with chromosome abnormalities (additional copy of X chromosome). The aim of this study was identification of the genetic basis of a case of tortoiseshell colour in a fertile Maine coon tomcat. Cytogenetic and molecular genetic studies were carried out with painting molecular probes (WCPP) specific to the X and Y sex chromosomes as well as a DNA microsatellite panel for the parentage verification of cats. Cytogenetic analysis revealed only a single set of sex chromosomes typical for male – 38,XY. The results of the microsatellite polymorphism obtained from DNA showed three alleles in locus FCA201 and four alleles in loci FCA149 and FCA441 in different tissues (blood, hair roots and testicles). Based on these results, the case was diagnosed as a true chimerism 38,XY/38,XY. To the best of our knowledge, this is the first case of a 38,XY/38,XY chimera diagnosed in cats, confirmed by genetic analysis.     

Analysis of bacterial communities in <Emphasis Type="Italic">Nannochloropsis</Emphasis> sp. cultures used for larval fish production

ABSTRACT:   Phytoplankton used in fish hatcheries is mass-cultured in the open air and usually contains large numbers of bacteria. In commercial fish production, the phytoplankton cultures are usually added into the larval rearing tanks; however, the numbers and types of bacteria introduced into the rearing tanks simultaneously are unknown. In this study, the bacterial community structures in Nannochloropsis sp. cultures were analyzed by using fluorescence in situ hybridization (FISH). A direct viable count (DVC)-FISH analysis was also performed as DVC is useful for the detection of actively growing cells. Total numbers of bacteria in Nannochloropsis sp. cultures ranged from 7.72 × 10⁵−2.39 × 10⁶ cells/mL. High proportions of the total bacteria (31.6–53.6%) in the Nannochloropsis sp. cultures showed growth potential. DVC-FISH analysis revealed that α-proteobacteria and the Cytophaga – Flavobacterium cluster were abundant in the bacterial community of actively growing cells. Thus, the high growth potentials of the distinct bacterial communities in Nannochloropsis sp. culture must influence the bacterial communities in larval rearing tanks.     

FISH 技术在芸薹属作物基因组研究中的应用进展

 FISH 技术是进行基因和重复DNA 序列在染色体上可视化作图的精确有效方法,已广泛应用于特异核苷酸序列的物理作图、基因组或染色体的识别、DNA 序列的定量分析以及着丝粒、染色质空间结构分析等方面。综述了FISH 技术在芸薹属作物基因组研究中的重要进展,并讨论了其应用前景。     

鲤鱼细菌性败血症的病原分离鉴定

本文报道了一种引起鲤鱼败血性传染病的致病菌，从发病鲤鱼的皮肤病灶和内脏器官均分离到该病的病原菌，用这种致病菌的纯培养物人工感染健康鲤鱼获得成功。根据其细菌形态，培养特性及生理生化性状，符合嗜水气单胞菌嗜水亚种（ＡｅｒｏｍｏｎａｓｈｙｄｒｏｐｈｉｌａＳｕｂｓｐ）。并对该菌的药物敏感性进行了试验，从１５种抗菌药物中选出了氯霉素、链霉素、四环素、卡那霉素、庆大霉素等几种该菌特别敏感的药物。文中还针对与嗜水气单胞菌特性比较相似的一些鱼类病原菌进行了鉴别诊断的讨论。     

污泥反硝化除磷-诱导磷结晶工艺中硝化池内的微生物特性

为了探究双污泥系统下反硝化除磷-诱导磷结晶工艺中硝化池内微生物特性,该文利用原位荧光杂交（fluorescence in situ hybridization,FISH）技术、电子显微镜扫描（scanning electron micrograph,SEM）方法和Image-Pro Plus（IPP）软件考察了该工艺中硝化细菌的种群结构、形态和硝化污泥微观三维结构图。结果表明：该工艺中硝化池内氨氧化细菌（ammonia-oxidizing bacteria,AOB）数量要多于亚硝酸盐氧化细菌（nitrite-oxidizing bacteria,NOB）,占总细菌的比例分别为46.2%,28.5%,且AOB处于污泥颗粒外层而NOB处于污泥颗粒内层,可能由于NOB利用AOB的代谢产物所致;工艺中硝化细菌多以球形或短杆菌为主,NOB生长时多以几个细胞形成小团聚体,而AOB生长时则形成大的团聚体;通过硝化污泥微观三维结构发现,污泥外层呈密实状而内层较疏松且有空洞存在,可能由于污泥外层和内层微生物的丰度差异、营养物质和溶解氧的浓度差异所致。此外,与传统的单污泥污水处理工艺相比,双污泥工艺明显地增强了硝化细菌的生长和富集能力。     

热休克蛋白70(HSP70)基因在中国对虾染色体上的定位

以热休克蛋白70(HSP70)基因为探针,利用荧光原位杂交(FISH)的方法,将其初步定位在中国对虾(Fenneropenaeus chinesis)染色体上。观察150组精巢细胞染色体,有111组染色体有3个杂交信号,占所观察的74％,由此得出,热休克蛋白70基因(HSP70)很可能存在于中国对虾减数分裂细胞3对染色体的3个位点上。本研究首次将功能基因定位在了对虾染色体上,为中国对虾的遗传物理图谱的构建提供了有效可行的方法。