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41.
Electrophoretic studies of the degree and pattern of polymorphism at two third-chromosome loci, esterase-6 (Est-6) and phosphoglucomutase (PGM), were carried out in three Drosophila melanogaster populations collected from different localities in Iraq: Mosul, Tuwaitha, and Basrah. The results show that only the Tuwaitha population was polymorphic for both loci; the other two populations were polymorphic for Est-6 and monomorphic for PGM. The allele frequency changes at both loci were followed for 20 generations in an experimental cage derived from the Tuwaitha population; it was found that there is a deviation from Hardy-Weinberg equilibrium at both loci toward the homozygote. 相似文献
42.
The fungusAspergillus flavipes was grown on a Czapeck sucrose medium; the biomass so obtained was treated with high concentration of sucrose to release intracellular metabolites. Sephadex G-75 chromatography of the latter yielded a pure protein having anti-trypsin activity in vitro. 相似文献
43.
Systematic Parasitology - Four previously established Raillietiella spp. are redescribed. Two of these, R. kochi and R. shipleyi from African monitor lizards, cannot be reliably separated, R.... 相似文献
44.
Definition of essential sequences and functional equivalence of elements downstream of the adenovirus E2A and the early simian virus 40 polyadenylation sites. 总被引:43,自引:21,他引:22
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In addition to the highly conserved AATAAA sequence, there is a requirement for specific sequences downstream of polyadenylic acid [poly(A)] cleavage sites to generate correct mRNA 3' termini. Previous experiments demonstrated that 35 nucleotides downstream of the E2A poly(A) site were sufficient but 20 nucleotides were not. The construction and assay of bidirectional deletion mutants in the adenovirus E2A poly(A) site indicates that there may be redundant multiple sequence elements that affect poly(A) site usage. Sequences between the poly(A) site and 31 nucleotides downstream were not essential for efficient cleavage. Further deletion downstream (3' to +31) abolished efficient cleavage in certain constructions but not all. Between +20 and +38 the sequence T(A/G)TTTTT was duplicated. Function was retained when one copy of the sequence was present, suggesting that this sequence represents an essential element. There may also be additional sequences distal to +43 that can function. To establish common features of poly(A) sites, we also analyzed the early simian virus 40 (SV40) poly(A) site for essential sequences. An SV40 poly(A) site deletion that retained 18 nucleotides downstream of the cleavage site was fully functional while one that retained 5 nucleotides downstream was not, thus defining sequences required for cleavage. Comparison of the SV40 sequences with those from E2A did not reveal significant homologies. Nevertheless, normal cleavage and polyadenylation could be restored at the early SV40 poly(A) site by the addition of downstream sequences from the adenovirus E2A poly(A) site to the SV40 +5 mutant. The same sequences that were required in the E2A site for efficient cleavage also restored activity to the SV40 poly(A) site. 相似文献
45.
The phylogeny of the hominoid primates: a statistical analysis of the DNA-DNA hybridization data 总被引:1,自引:0,他引:1
Sibley and Ahlquist compared the single-copy nuclear DNA sequences of the
hominoid primates using DNA-DNA hybridization. From this data set they
estimated a phylogeny that clusters man and chimpanzees using a distance
Wagner procedure. However, no assessment of statistical confidence in this
estimated phylogeny was made, despite the fact that their data set contains
internal inconsistencies concerning the correct branching order. This paper
presents a modification of Pielou's Q- statistic that allows one to make
nonparametric tests of phylogenetic relationship from distance data. The
results of this analysis indicate that the estimated phylogeny of Sibley
and Ahlquist is without statistical significance owing to the internal
inconsistencies of the data set. A survey and additional analyses of other
types of molecular data indicate that the phylogeny that clusters
chimpanzees and gorillas and has the human lineage splitting off earlier is
statistically consistent with all the molecular data (including the DNA-DNA
hybridization data), whereas the phylogeny estimated by Sibley and Ahlquist
can be rejected at the 5% level using the data on restriction- endonuclease
sites in the mitochondrial genome.
相似文献
46.
A I Mustafa B H Ali A M Satti 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1985,81(1):167-169
Furazolidone (FZ) was given to Nubian goats at the recommended therapeutic dose of 10 mg/kg body wt, for 5 days. The animals were slaughtered 24 hr after the last dose, and their livers, gluteal muscles, kidneys and hearts analysed for FZ residues by an HPLC method with a detection limit of 0.05 micrograms g-1. The drug was detected in the muscle and liver at concentrations of 0.256 +/- 0.009, 0.101 +/- 0.016 micrograms g-1 tissue, respectively. No detectable concentrations of the drug were found in the kidney and heart. 相似文献
47.
Immunoaffinity purified Sm/RNP antigens from buffalo and goat liver were studied to determine the role of RNA and proteins
towards the antigenicity of Sm and RNP antigens. A more direct approach using enzyme-linked immunosorbent assay on nylon beads
has been utilized to look into the problem. The effect of enzyme treatment and the role of RNA and protein fractions in influencing
antigenicity have been described. RNA seems to be involved in the maintenance of RNP specific polypeptides in suitable conformation
so as to keep them in solution. Removal of RNA leads to insolubilization of RNP specific polypeptides. Antibodies to Sm and
RNP antigens have been shown to cross react with poly A containing heterogeneous nuclear ribonucleoprotein with no cross reactivity
with thymus RNA or DNA. 相似文献
48.
Summary Our ultrastructural study of the retinal pigmented epithelium (RPE) of young, pigmented, and mature silver eels, (Anguilla anguilla), revealed the presence of retinomotor responses in the RPE of both growth stages. Furthermore, while the overall fine structure of the RPE is similar to that of other vertebrates, specific structures were also found. These include various forms of lipid droplets, intercellular membranous whorls, multitubular bodies, macrophages, melanolysosomes, and myeloid bodies (large and numerous in young eels). Structural variations in cellular organelles of the RPE according to different adaptive states (light, dark) and growth stages (young, mature) of the animal are discussed with respect to their significance in its complex life cycle. 相似文献
49.
Shahid Ali A. Sitaramayya K. Sree Kumar Padmanabhan S. Krishnan 《The Biochemical journal》1974,137(1):85-92
1. An inhibitor of cytoplasmic guanine deaminase of rat liver was isolated from liver ;heavy mitochondrial' fraction after freezing and thawing and treatment with Triton X-100. 2. Submitochondrial fractionation revealed that the inhibitor was localized in the outer-membrane fraction. 3. The method of purification of inhibitor, involving precipitation with (NH(4))(2)SO(4) and chromatography on DEAE-cellulose, its precipitability by trichloroacetic acid and the pattern of absorption in the u.v. indicated that the inhibitor was a protein. In confirmation, tryptic digestion of the isolated material resulted in destruction of the inhibitor activity. The inhibitor was stable to acid, but labile to heat. 4. The isolated inhibitor required phosphatidylcholine (lecithin) for activity. Phosphatidylcholine also partially protected the inhibitor against heat inactivation. 5. When detergent treatment was omitted, the inhibitor activity of frozen mitochondria was precipitated by (NH(4))(2)SO(4) in a fully active form without supplementation with phosphatidylcholine, indicating that Triton X-100 ruptured the linkage between inhibitor and lipid. 6. A reconstituted sample of inhibitor-phosphatidylcholine complex was precipitated in a fully active form by dialysis against 2-mercaptoethanol, but treatment of the precipitate with NaCl yielded an extract which was inactive unless supplemented with fresh phosphatidylcholine. 7. We interpret the results as evidence that the inhibitor was present in vivo as a lipoprotein and that once the complex was dissociated by the action of detergent and the protein precipitated, there was an absolute need for exogenous phosphatidylcholine for its activity. The manner in which inhibitor associated with the outer membrane of rat liver mitochondria might regulate the activity of the enzyme in the supernatant has been suggested. 相似文献
50.
Ali H. Qizilbash 《CMAJ》1974,110(2):185-186
A case of early bilateral serous papillary adenocarcinoma of the ovaries in an asymptomatic 58-year-old woman was diagnosed by the discovery of psammoma bodies in routine cervicovaginal and endometrial smears. Multiple small foci of carcinoma in-situ involving both fallopian tubes were also present. The significance of psammoma bodies in the cervicovaginal smear is discussed and the literature on the subject briefly reviewed. 相似文献