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In situ digestion of metaphase and polytene chromosomes and of interphase nuclei in different cell types ofDrosophila nasuta with restriction enzymes revealed that enzymes like AluI, EcoRI, HaeIII, Sau3a and SinI did not affect Giemsa-stainability
of heterochromatin while that of euchromatin was significantly reduced; TaqI and SalI digested both heterochromatin and euchromatin
in mitotic chromosomes. Digestion of genomic DNA with AluI, EcoRI, HaeIII, Sau3a and KpnI left a 23 kb DNA band undigested
in agarose gels while withTaqI, no such undigested band was seen. TheAluI resistant 23 kb DNA hybridized insitu specifically with the heterochromatic chromocentre. It appears that the digestibility of heterochromatin region in genome
ofDrosophila nasuta with the tested restriction enzymes is dependent on the availability of their recognition sites. 相似文献
3.
Early iron deficiency in rat does not affect the weight or the protein, DNA, and RNA content but results in a slight reduction in gamma-aminobutyric acid (GABA) (13%, p less than 0.01) and glutamic acid (20%, p less than 0.001) content of the brain. The activities of the two GABA shunt enzymes, glutamate dehydrogenase and GABA-transaminase, and of the NAD+-linked isocitrate dehydrogenase (ICDH) were inhibited whereas the glutamic acid decarboxylase, mitochondrial NADP+-linked ICDH, and succinic dehydrogenase activities remained unaltered in brain. On rehabilitation with the iron-supplemented diet for 1 week, these decreased enzyme activities in brain attained the corresponding control values. However, the hepatic nonheme iron content increased to about 80% of the control, after rehabilitation for 2 weeks. A prolonged iron deficiency resulting in decreased levels of glutamate and GABA may lead to endocrinological, neurological, and behavioral alterations. 相似文献
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Summary During an earlier investigation, microtubules were observed at the periphery of invasion processes in the developing syncytial tapetum ofTradescantia virginiana L. They were also associated with membranous sacs that accumulate adjacent to tetrads, with putative fusion sites where the tapetal plasmodium is initiated, and, in postmeiotic stages, with the perispore membrane that encloses the developing spore cells. Colchicine was administered to developing flower buds to investigate the roles of these microtubules. The results indicate that microtubules neither initiate nor guide the tapetal invasion of the loculus. The treatments, however, resulted in absence of cell coat from invasion processes and prevention of cell fusion. They also inhibited polarized migration of membrane sacs and removed the associated microtubules. The development of an organized secretory apparatus at the perispore membrane was disrupted, with subsequent disordered deposition of sporopollenin in the extracellular spaces of the partially-fused plasmodium. The results suggest that microtubules participate in the formation and internal spatial organization of the tapetal plasmodium, and establishment of a secretory surface that normally produces sporopollenin at the tapetum-microspore interface. 相似文献
6.
Hentriacontane, β-sitosterol and ursolic acid have been isolated from roots of Boerhaavia diffusa (Linn). 相似文献
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A pollen-morphology study of Amaranthus spinosus, A. dubius, and their hybrids has been carried out. Three pollen types have been observed, namely (1) Type A: micrograins; (2) Type B: grains with smaller pores; and (3) Type C: grains with larger pores. Type B is characteristic of A. spinosus, Type C of A. dubius, and the micrograins of the hybrids. Pollen size range, and frequency of the various morphotypes serve to throw light on the biosystematics of the plants studied. 相似文献
9.
Effects of localized low (2.5 Gy) and high (10 Gy) levels of gamma irradiation on the testis of albino rats were studied. A marked increase in the testicular total lipid, phospholipid and cholesterol content was observed at all post-treatment intervals except at 16 weeks where the contents decreased. A significant decrease in the activity of acid phosphatase/g of testis was seen at both the doses, the minimum value being at 4 weeks. The decrease in acid phosphatase activity is correlated with the state of germ cell population in seminiferous tubule which is found to be depleted at 4 week interval. The alkaline phosphatase activity/g testis however, showed a significant increase, the maximum being at 4 weeks post-treatment. Thereafter, the values of the enzyme activity showed a slight recovery at 16 weeks post-irradiation. ATPase activity increased initially followed by a significant decrease at all post-treatment intervals. 相似文献
10.
Calothrix sp. M103, enhanced by addition of iron and siderophore production was used as a biofertilizer. The strain was isolated from a colony on the surface root of a rice plant from a rice field in Bangladesh. It showed a marked and immediate increase in nitrogenase activity in response to the addition of iron and also a normal activity (compared with the control) under siderophore production. The addition of iron to iron-limited cultures resulted in a rapid increase in algal iron (11-fold) followed by a marked increase (9-fold) in nitrogenase activity, reaching about 11.8 kg N/ha/crop. This was more than twice the amount of nitrogen usually fixed by the alga during normal growth (controlled conditions), suggesting that pulsing algal inocula with iron would increase the efficiency of algae as a biofertilizer. Indeed, the use of an iron-pulsed inoculum of this strain as a biofertilizer resulted in an increase in the yield of sweetcorn by ca 143% over that produced by the control (no algal inoculation) and to ca a 73% increase over that produced by the normal inoculum (unpulsed with iron). The ability of this strain to produce siderophores has also led to both normal (compared with the control) nitrogenase activity as well as normal growth, which shows a marked contrast to other circumstances where the non-siderophore producing strains showed no growth at all. The significance of these observations on the enhancement of biofertilizer technology is discussed. 相似文献