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1.
Silver staining of nucleolar organizing regions (NOR) is common, but a standard protocol is lacking. A modification of a rapid silver nitrate staining technique for NORs is presented here. Advantages of the modified technique include reliability, speed, cost and the fact that it can be carried out in the light.  相似文献   

2.
We used silver nitrate staining, CMA3 and FISH to study the chromosomal localization of both the major ribosomal genes and the nucleolar organizer regions as well as that of the minor ribosomal genes (5S rDNA) in two species of Batoidea, Taeniura lymma (Dasyatidae) and Raja montagui (Rajidae). In both species, all the metaphases examined showed the presence of multiple NOR-bearing sites, while the gene for 5S rRNA proved to be localized on two chromosome pairs. Furthermore, one of the two 5S rDNA sites in T. lymma was shown to be co-localized with the major ribosomal cluster. The presence of multiple nucleolar organizer regions in the two species might be interpreted as being the result of intraspecific polymorphisms, or as a phenomenon of the amplified transposition of mobile elements of the genome. We also determined the nucleotide sequence of the 5S rRNA gene, consisting of 564 bp in R. montagui and 612 bp in T. lymma. We also found TATA-like and (TGC)n trinucleotides, (CA)n dinucleotides and (GTGA)n tetranucleotides, which probably influence gene regulation.  相似文献   

3.
介绍一种简单、经济的同工酶染色方法:用熔化的0.4%琼脂糖处理滤纸备用,染色前将滤纸浸于同工酶染色液中,染色时将滤纸盖在聚丙烯酸胺胶上,然后将胶放在有盖塑料盒中保温染色,染色时间要比普通方法略长。染色后将胶和滤纸移入固定液中用镊子除去滤纸.  相似文献   

4.
用大鳍Hu、粗唇Wei、瓦氏黄颡鱼等的胸鳍棘作为实验材料,用1%-5%的硝酸脱钙切片后,鉴定年龄。为适应大规模的年龄鉴定,对常规的组织切片步骤和时间进行了简化、缩短。与传统的锯片法及磨片法相比,该方法易于操作,有助于准确的年龄鉴定、年轮半径测量和生长推算,特别适用于中、小型无鳞鱼类的年龄鉴定。  相似文献   

5.
A method is described for staining lipid in fourth-stage dispersal juvenile nematodes fixed with formal-acetic fixative (FA4:1). Bursaphelenchus xylophilus fourth-stage dispersal juveniles were fixed with hot FA4:1 for 24 hours, excess fixative was removed, and a solution of saturated oil red O in 96% ethanol added and allowed to sit for 25 minutes at 60 C. Excess oil red O was removed, nematodes were washed twice with 70% ethanol, and were processed to pure glycerin. Lipid droplets within the nematodes were viewed by light microscopy and appeared as dark red spheres of various sizes. Computerized image analysis was used to quantify lipid droplet area.  相似文献   

6.
周密  李渝成 《遗传学报》1989,16(3):184-187
本文报道了一种显示鱼类染色体G-带的BrdU-BsG方法。采用肾细胞短期培养,收获前12小时加入BrdU,使终浓度为10μg/ml。制片经HCl、Ba(OH)_2处理,4×SSC温育。Giemsa染色,显示出白鲢的G-带。其带纹细致清晰,一个细胞的单倍染色体上显示带纹达200条以上,是目前已报道的鱼类多重带中带纹最多的,且反差明显,带纹有特征性,结果较稳定。根据实验结果初步建立了白鲢的G-带模式图。  相似文献   

7.
一、临猗县农业生产条件特点及存在问题临猗县位于山西西南部,是晋南盆地中的一个大县。全县面积1356km~2,耕地1.0×10~5ha,水浇地5.27×10~4ha,占耕地的52.7%,人均占有耕地0.227ha。地势平坦,土地肥沃,农业生产条件较好。年降水量为500mm 左右,最高年份曾达到849.8mm,其中5—10月份的降雨量为450mm 左右,同期≥10℃的活动积温在  相似文献   

8.
The 5S rRNA genes of maize are located in the long arm of chromosome 2 (88% of the distance from the centromere to the end) and organized in a 320-bp repeat. Genomic blots of maize DNA digested with the restriction enzymes BamHI and MspI reveal ladders of bands in multiples of 320 bp. Analysis of 5S rDNA from genomic clones reveals that the ladders are due to both modification and divergence of the 5s rDNA nucleotide sequence.  相似文献   

9.
To systematically estimate the gene duplication events in closely related species, we have to use comparative genomic approaches, either through genomic sequence comparison or comparative genomic hybridization (CGH). Given the scarcity of complete genomic sequences of plant species, in the present study we adopted an array based CGH to investigate gene duplications in the genus Arabidopsis. Fragment genomic DNA from four species, namely Arabidopsis thaliana, A. lyrata subsp. lyrata, A. lyrata subsp. petraea, and A. halleri, was hybridized to Affymetrix (Santa Clara, CA, USA) tiling arrays that are designed from the genomic sequences of A. thaliana. Pairwise comparisons of signal intensity were made to infer the potential duplicated candidates along each phylo-genetic branch. Ninety-four potential candidates of gene duplication along the genus were identified. Among them, the majority (69 of 94) were A. thaliana lineage specific. This result indicates that the array based CGH approach may be used to identify candidates of duplication in other plant genera containing closely related species, such as Oryza, particularly for the AA genome species. We compared the degree of gene duplication through retrotransposon between O. sativa and A. thaliana and found a strikingly higher number of chimera retroposed genes in rice. The higher rate of gene duplication through retroposition and other mechanisms may indicate that the grass species is able to adapt to more diverse environments.  相似文献   

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