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321.
322.
Particle-bombardment-mediated co-transformation of elite Chinese rice cultivars with genes conferring resistance to bacterial blight and sap-sucking insect pests 总被引:16,自引:0,他引:16
323.
Hydroxocobalamin is present in fairly large proportions both in foods and in the human body and apparently plays an important biological role. Since cyanocobalamin seems to play hardly any significant biochemical role in healthy humans, several physicians prefer to administer hydroxocobalamin to vitamin B12 deficient patients. We find that hydroxocobalamin in solution isomerizes very readily at room and lower temperatures. Our observations raise the question whether "Mother Nature" has gone awry in using an easily convertible substance like hydroxocobalamin or that the new isomeric forms play some significant role. These observations may also have a bearing on the reported occurrence of unidentified corrinoids in animal tissues, human red cells, liver and brain. 相似文献
324.
We have extended our previous study on the suppression of frameshift mutants by Escherichia coli thyA mutants by assaying suppression of 15 rIIB frameshift mutants of bacteriophage T4 on one of our suppressing thyA mutant strains. The majority of insertion mutants were suppressible, whereas none of the deletion mutants tested was suppressible. Frameshift suppression could be inhibited by adding thymidine to the assay medium, but was not affected by the presence of a restrictive rpsL mutation in the host strain. We suggest that the frameshift suppression event occurs at a nonsense codon generated by the frameshift mutation. 相似文献
325.
W D Heyer P Thuriaux J Kohli P Ebert H Kersten C Gehrke K C Kuo P F Agris 《The Journal of biological chemistry》1984,259(5):2856-2862
The screening of antisuppressor mutants of the yeast Schizosaccharomyces pombe has been successfully accomplished with high resolution liquid chromatographic methods for the analysis of tRNA nucleosides. Antisuppressor mutations reduce or abolish the function of nonsense suppressor-tRNAs or other informational suppressors. Nonradioactive or 35S-labeled unfractionated tRNA from various strains was digested to nucleosides and analyzed by high performance liquid chromatography. The mutant sin3 has lost the nucleoside 5-(methoxycarbonylmethyl)-2-thiouridine from its tRNA in comparison to parental strains. In eukaryotes this nucleoside is found at the first position of the anticodon (wobble position) in several isoacceptor tRNAs that preferentially recognize codons ending with adenosine. The sin3 mutation reduces the efficiency of UGA and UAA suppressor tRNASer and suppressor tRNALeu. The genetic cosegregation of modification loss, antisuppressor phenotype, and a change in cell size is demonstrated. This indicates that a single mutation in the structural gene for a tRNA modification enzyme causes the three different phenotypes. 相似文献
326.
Isolation of a human anti-haemophilic factor IX cDNA clone using a unique 52-base synthetic oligonucleotide probe deduced from the amino acid sequence of bovine factor IX 总被引:36,自引:10,他引:26
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M Jaye H de la Salle F Schamber A Balland V Kohli A Findeli P Tolstoshev J P Lecocq 《Nucleic acids research》1983,11(8):2325-2335
A unique 52mer oligonucleotide deduced from the amino acid sequence of bovine Factor IX was synthesized and used as a probe to screen a human liver cDNA bank. The Factor IX clone isolated shows 5 differences in nucleotide and deduced amino acid sequence as compared to a previously isolated clone. In addition, precisely one codon has been deleted. 相似文献
327.
A study of the problem of structural variants of proteins and their relative contribution to the expressed immunological and
biological activity has been initiated using sheep and buffalo prolactins as models. The feasibility of obtaining immunologically
and biologically active prolactin in high yields from the discarded ’acid pellet’ of sheep and buffalo pituitaries has been
demonstrated. This permits use of the same batch of glands for purifying lutropin, follitropin and prolactin as side fractions.
The major component in preparations of buffalo prolactin has a molecular size of 24 kDa. The preparations were active in a
radioligand binding inhibition assay and in a rat liver based radioreceptor assay. Charge and size isomers of sheep prolactin
and buffalo prolactin have been observed. The reference sheep prolactin did not, in preliminary work, give any indication
of being glycosylated. However radioactive sulphate was found to be incorporated into prolactin-rich fractions of sheep and
buffalo pituitariesin vitro. By physico-chemical and immunochemical criteria the [35S]-labelled material was similar to standard reference prolactin. The structural implications of sulphation have been probed.
Presented at the 3rd National Symposium on Bioorganic Chemistry, 1987, Hyderabad. 相似文献
328.
329.
V K Sharma S Kaur I Kaur M Thakur C Vaishnavi M Kohli N K Ganguly 《Indian journal of experimental biology》1992,30(5):451-453
Thirty nine untreated patients of bacilliferous leprosy with a mean bacteriological index of 4.8 and morphological index of 1.3% formed the study group. Adenosine triphosphate assay was carried out by (i) enzyme treatment method in 18 patients and (ii) percoll buoyant density gradient method in 21 patients. ATP content obtained by percoll buoyant density gradient method was significantly higher than that obtained by enzyme treatment method. Percoll buoyant density centrifugation for purification and isolation of bacilli from human leproma is simplier, quicker and can serve as an alternate method of enzyme treatment. 相似文献
330.
R.K. Bhatnagar S. Ahmad K.K. Kohli K.G. Mukerji T.A. Venkitasubramanian 《Biochemical and biophysical research communications》1982,104(4):1287-1292
The presence of the components of polysubstrate monooxygenase (PSMO) activity, viz., cytochrome P-450 and NADPH cytochrome P-450 reductase has been established for the first time in the microsomes of . The microsomes were able to metabolize benzphetamine. NADPH cytochrome P-450 reductase, benzphetamine metabolism and aflatoxin production was increased by the presence of phenobarbitone (PB, 2mg/ml) in the medium. These results demonstrate that induction of PSMO activity could be a prerequisite for increased production of aflatoxins, since hydroxylation of intermediates is an obligatory step in aflatoxin biosynthesis. 相似文献