排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
Targeted disruption of the mouse topoisomerase I gene by camptothecin selection. 总被引:4,自引:0,他引:4 下载免费PDF全文
S G Morham K D Kluckman N Voulomanos O Smithies 《Molecular and cellular biology》1996,16(12):6804-6809
2.
3.
The 18S ribosomal RNAs of 21 tetrapods were sequenced and aligned with five
published tetrapod sequences. When the coelacanth was used as an outgroup,
Lissamphibia (living amphibians) and Amniota (amniotes) were found to be
statistically significant monophyletic groups. Although little resolution
was obtained among the lissamphibian taxa, the amniote sequences support a
sister-group relationship between birds and mammals. Portions of the 28S
ribosomal RNA (rRNA) molecule in 11 tetrapods also were sequenced, although
the phylogenetic results were inconclusive. In contrast to previous
studies, deletion or down- weighting of base-paired sites were found to
have little effect on phylogenetic relationships. Molecular evidence for
amniote relationships is reviewed, showing that three genes
(beta-hemoglobin, myoglobin, and 18S rRNA) unambiguously support a
bird-mammal relationship, compared with one gene (histone H2B) that favors
a bird- crocodilian clade. Separate analyses of four other genes (alpha-
crystallin A, alpha-hemoglobin, insulin, and 28S rRNA) and a combined
analysis of all sequence data are inconclusive, in that different groups
are defined in different analyses and none are strongly supported. It is
suggested that until sequences become available from a broader array of
taxa, the molecular evidence is best evaluated at the level of individual
genes, with emphasis placed on those studies with the greatest number of
taxa and sites. When this is done, a bird-mammal relationship is most
strongly supported. When regarded in combination with the morphological
evidence for this association, it must be considered at least as plausible
as a bird-crocodilian relationship.
相似文献
4.
Mitochondrial DNAs of six morphologically different Phytophthora species were digested with 15 restriction enzymes. The numbers of restriction fragments obtained differed considerably from those theoretically expected for random base distribution. Enzymes with relatively many G and C in their recognition sequences produced significantly larger numbers of fragments. Moreover, fragments generated by most of these enzymes were more often shared by two or more species than those from enzymes with more A and T in their recognition sequence. It is concluded that base distribution in mitochondrial DNA of Phytophthora is heterogeneous,AT-rich stretches occurring scattered over the mitochondrial genome and GC-rich regions present in conserved sequences, presumably genes. A practical consequence for taxonomic RFLP studies is that optimal enzymes can be selected, depending on the desired level of resolution. 相似文献
5.
6.
7.
Mitochondrial glycerol-3-phosphate acyltransferase-deficient mice have reduced weight and liver triacylglycerol content and altered glycerolipid fatty acid composition 总被引:6,自引:0,他引:6 下载免费PDF全文
Hammond LE Gallagher PA Wang S Hiller S Kluckman KD Posey-Marcos EL Maeda N Coleman RA 《Molecular and cellular biology》2002,22(23):8204-8214
Microsomal and mitochondrial isoforms of glycerol-3-phosphate acyltransferase (GPAT; E.C. 2.3.1.15) catalyze the committed step in glycerolipid synthesis. The mitochondrial isoform, mtGPAT, was believed to control the positioning of saturated fatty acids at the sn-1 position of phospholipids, and nutritional, hormonal, and overexpression studies suggested that mtGPAT activity is important for the synthesis of triacylglycerol. To determine whether these purported functions were true, we constructed mice deficient in mtGPAT. mtGPAT(-/-) mice weighed less than controls and had reduced gonadal fat pad weights and lower hepatic triacylglycerol content, plasma triacylglycerol, and very low density lipoprotein triacylglycerol secretion. As predicted, in mtGPAT(-/-) liver, the palmitate content was lower in triacylglycerol, phosphatidylcholine, and phosphatidylethanolamine. Positional analysis revealed that mtGPAT(-/-) liver phosphatidylethanolamine and phosphatidylcholine had about 21% less palmitate in the sn-1 position and 36 and 40%, respectively, more arachidonate in the sn-2 position. These data confirm the important role of mtGPAT in the synthesis of triacylglycerol, in the fatty acid content of triacylglycerol and cholesterol esters, and in the positioning of specific fatty acids, particularly palmitate and arachidonate, in phospholipids. The increase in arachidonate may be functionally significant in terms of eicosanoid production. 相似文献
8.
Moulinath Acharya Suddhasil Mookherjee Ashima Bhattacharjee Sanjay KD Thakur Arun K Bandyopadhyay Abhijit Sen Subhabrata Chakrabarti Kunal Ray 《BMC molecular biology》2007,8(1):21
Background
We investigated the molecular basis of primary open-angle glaucoma (POAG) using Opticin (OPTC) as a candidate gene on the basis of its expression in the trabecular meshwork cells involved in the disease pathogenesis. Two hundred POAG patients and 100 controls were enrolled in this study. The coding sequence of OPTC was amplified by PCR from genomic DNA of POAG patients, followed by SSCP, DHPLC and DNA sequencing. Subsequent bioinformatic analysis, site-directed mutagenesis, quantitative RT-PCR and western blot experiments were performed to address the functional significance of a 'silent' change in the OPTC coding region while screening for mutations in POAG patients. 相似文献9.
The effect of the administration of the mycotoxins OTA, ZEA and DON alone resp. in combination on animal health and the residue behavior of pigs from 50 – 60 kg living weight over 90 days was investigated in 4 separate studies. Due to its fast metabolisation the administration of 1000 µg DON resp. 250 µg ZEA per kg feed alone or in combination with other mycotoxins does not lead to detectable residues of these mycotoxins in organs and tissues. Therefore these mycotoxins should not be relevant to the consumer.There is an effect of the simultaneous administration of ZEA resp. DON on the metabolisation resp. secretion of OTA. OTA is of relevance from the point of view of residue toxicology. 相似文献
10.
An anchored restriction-mapping approach applied to the genetic analysis of the Anopheles gambiae malaria vector complex 1 总被引:1,自引:0,他引:1
We introduce here a simple approach for rapidly determining restriction
maps for a number of regions of a genome; this involves "anchoring" a map
with a rare restriction site (in this case the seldom-cutting EagI)
followed by partial digestion of a frequent-cutting enzyme (e.g., Sau 3A).
We applied this technology to five species of the Anopheles gambiae
complex. In a single Southern blot we obtained about a 15-kb restriction
map each for the mtDNA, rRNA gene, and a scnDNA region for each of five
species. Phylogenetic analyses of these regions yield trees at odds with
the more traditional chromosome inversion-based trees. The value of the
approach for systematic purposes is the ease with which several large,
independent regions of the genome can be quickly assayed for molecular
variation.
相似文献