排序方式: 共有16条查询结果,搜索用时 190 毫秒
11.
In order to analyze chromosomes for possible numerical and structural alterations in response to exposure to organotin(IV) compounds, gastropod Truncatella subcylindrica specimens were treated with dibutyltin(IV) and tributyltin(IV) chloride solutions with different exposure times. Experimental evidence suggests that tributyltin(IV) chloride is more toxic to this organism than dibutyltin(IV) dichloride at low concentrations. Furthermore, the toxicity responses to these organotin(IV) derivatives seem to be proportional to both concentration and exposure time. The following structural lesions have been identified by comparative analysis of spermatocyte chromosomes from untreated specimens and specimens treated with organotin(IV) compounds: (1) breakages; (2) bridging; (3) irregular outline; and (4) light areas after staining with acetic orcein. In this respect, dibutyltin(IV) and tributyltin(IV) chlorides seem to have an effect similar to that of colchicine. 相似文献
12.
I. F. Zhimulev E. S. Belyaeva V. F. Semeshin G. V. Pokholkova E. B. Kokoza T. Yu. Kozlova S. A. Demakov N. I. Mal'ceva O. V. Demakova M. L. Balasov D. E. Koryakov I. V. Makunin N. V. Belousova 《Russian Chemical Bulletin》1995,44(9):1553-1570
The results of the works carried out in the Laboratory of Molecular Cytogenetics (Institute of Cytology and Genetics of Siberian Branch of the RAS, Novosibirsk) devoted to the molecular genetic analysis of main units of polytene chromosomes, bands, interbands, and puffs, as well as intercalary and pericentric heterochromatin, are summarized. The results are discussed in terms of the dynamic model of organization of polytene chromosomes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1622–1638, September, 1995. 相似文献
13.
Menzerath‐Altmann law is a general law of human language stating, for instance, that the longer a word, the shorter its syllables. With the metaphor that genomes are words and chromosomes are syllables, we examine if genomes also obey the law. We find that longer genomes tend to be made of smaller chromosomes in organisms from three different kingdoms: fungi, plants, and animals. Our findings suggest that genomes self‐organize under principles similar to those of human language. © 2009 Wiley Periodicals, Inc. Complexity, 2010 相似文献
14.
用地戈辛标记的原位杂交技术研究黄鳝二价体上rRNA基因的多态性.共检测到:数目和位置多态;杂交信号形态多态;rRNA基因的联合现象;7号二价体上可移动的rRNA基因位点;rRNA基因的串联重复;rRNA基因杂交信号周围的微信号密集等6种多态现象.还对本研究结果进行了详细地讨论. 相似文献
15.
Fan Yihui Zhang Xiaohong Bai Jing Mao Renfang Lei Qingquan 《Applied Surface Science》2007,253(12):5281-5286
In this study, we used calyculin A to induce premature condensed chromosomes (PCC). S-phase PCC is as “pulverized” appearance when viewed by light microscopy. Then, we applied atomic force microscopy (AFM) to investigate the ultrastructual organization of S-phase PCC. S-phase PCC shows ridges and grooves as observed by AFM. After trypsin treatment, chromosome surface roughness is increased and chromosome thickness is decreased. At high magnification, the ridges are composed of densely packed 30 nm chromatin fibers which form chromosome axis. Around the ridges, many 30 nm chromatin fibers radiate from center. Some of the 30 nm chromatin fibers are free ends. The grooves are not real “gap”, but several 30 nm chromatin fibers which connect two ridges and form “grid” structure. There are four chromatin fibers detached from chromosome: two free straight 30 nm chromatin fibers, one loop chromatin fiber and one straight combining with loop chromatin fiber. These results suggested that the S-phase PCC was high-order organization of 30 nm chromatin fibers and the 30 nm chromatin fibers could exist as loops and free ends. 相似文献
16.
Caroline P. Shepard Raymond G. Emehiser Saswata Karmakar Patrick J. Hrdlicka 《Molecules (Basel, Switzerland)》2023,28(1)
The development of chemically modified oligonucleotides enabling robust, sequence-unrestricted recognition of complementary chromosomal DNA regions has been an aspirational goal for scientists for many decades. While several groove-binding or strand-invading probes have been developed towards this end, most enable recognition of DNA only under limited conditions (e.g., homopurine or short mixed-sequence targets, low ionic strength, fully modified probe strands). Invader probes, i.e., DNA duplexes modified with +1 interstrand zippers of intercalator-functionalized nucleotides, are predisposed to recognize DNA targets due to their labile nature and high affinity towards complementary DNA. Here, we set out to gain further insight into the design parameters that impact the thermal denaturation properties and binding affinities of Invader probes. Towards this end, ten Invader probes were designed, and their biophysical properties and binding to model DNA hairpins and chromosomal DNA targets were studied. A Spearman’s rank-order correlation analysis of various parameters was then performed. Densely modified Invader probes were found to result in efficient recognition of chromosomal DNA targets with excellent binding specificity in the context of denaturing or non-denaturing fluorescence in situ hybridization (FISH) experiments. The insight gained from the initial phase of this study informed subsequent probe optimization, which yielded constructs displaying improved recognition of chromosomal DNA targets. The findings from this study will facilitate the design of efficient Invader probes for applications in the life sciences. 相似文献