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1.
2.
Anonymous nuclear DNA markers in the American oyster and their implications for the heterozygote deficiency phenomenon in marine bivalves 总被引:4,自引:0,他引:4
A puzzling population-genetic phenomenon widely reported in allozyme
surveys of marine bivalves is the occurrence of heterozygote deficits
relative to Hardy-Weinberg expectations. Possible explanations for this
pattern are categorized with respect to whether the effects should be
confined to protein-level assays or are genomically pervasive and expected
to be registered in both protein- and DNA-level assays. Anonymous nuclear
DNA markers from the American oyster were employed to reexamine the
phenomenon. In assays based on the polymerase chain reaction (PCR), two
DNA-level processes were encountered that can lead to artifactual genotypic
scorings: (a) differential amplification of alleles at a target locus and
(b) amplification from multiple paralogous loci. We describe symptoms of
these complications and prescribe methods that should generally help to
ameliorate them. When artifactual scorings at two anonymous DNA loci in the
American oyster were corrected, Hardy-Weinberg deviations registered in
preliminary population assays decreased to nonsignificant values.
Implications of these findings for the heterozygote-deficit phenomenon in
marine bivalves, and for the general development and use of PCR-based
assays, are discussed.
相似文献
3.
Oxidation of glucose to 2,5-diketogluconic acid by Erwinia herbicola was inhibited at 100% dissolved O2 tension (DOT) relative to air at 1 atm. Gluconic acid accumulation, however, increased under this condition. The negative influence of the high DOT is attributed to a 10-fold decrease in 2-ketogluconate dehydrogenase activity.The authors are with the Department of Biotechnology, Regional Research Laboratory, Canal Road, Jammu Tawi-180001, India 相似文献
4.
A simple and reproducible procedure for the recovery of plasmid DNA is described. The method was standardised for the purification of plasmids from Gluconobacter oxydans ATCC9937. The protocol is based on the use of glass microfibre filter paper for entrapment of DNA and its subsequent recovery by an elution buffer. The method precludes the use of phenol and butanol for the removal of proteins and ethidium bromide respectively, therefore, making the procedure inexpensive and gentle. 相似文献
5.
S. Koul V. Verma S. Johri G. N. Qazi 《World journal of microbiology & biotechnology》1995,11(2):234-235
Erwinia herbicola (ATCC 21998), a facultative anaerobe, has two plasmids: pVQ1 and pVQ2. Curing with mitomycin C indicated that pVQ2 was cryptic but pVQ1, a 7.4-kb plasmid, bears a 4.3SacI fragment which strongly hybridized to the C-terminal region of the glucose dehydrogenase gene ofAcinetobacter calcoaceticus. A restriction map of plasmid pVQ1 is presented.The authors are with the Department of Biotechnology, Regional Research Laboratory, Canal Road, Jammu Tawi-180 001, India; 相似文献
6.
Body weight, testicle size and peripheral testosterone concentrations were measured in 35 water buffalo bulls at 5, 15, 17, 21, 25 and 38 months of age. These parameters were studied in all animals during the same month (October), so the changes due to age were independent of changes in photoperiod and temperature. Body weight increased linearly with age. The testicular size measured in terms of scrotal circumference as related to age, showed a curvilinear increase; the average rate of testicular growth was maximum between 15 and 25 months. Plasma testosterone levels were low between 5 and 21 months. A significant rise in plasma concentration of testosterone was observed at 25 months reaching peak levels at 38 months. The mean age of sexually mature bulls at the time of first ejaculation of semen with motile sperm, was 24.9±0.9 months (n=9). It has been concluded that in the Nili-Ravi buffalo bulls the sexually quiescent period (prepubertal) extends up to 15 months of age and sexual maturation as indicated by the presence of motile sperm in the ejaculate is attained at about 25 months. 相似文献
7.
Basolateral plasma membrane localization of ouabain-sensitive sodium transport sites in the secretory epithelium of the avian salt gland
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The distribution of Na+ pump sites (Na+-K+-ATPase) in the secretory epithelium of the avian salt gland was demonstrated by freeze-dry autoradiographic analysis of [(3)H] ouabain binding sites. Kinetic studies indicated that near saturation of tissue binding sites occurred when slices of salt glands from salt-stressed ducks were exposed to 2.2 μM ouabain (containing 5 μCi/ml [(3)H]ouabain) for 90 min. Washing with label-free Ringer's solution for 90 min extracted only 10% of the inhibitor, an amount which corresponded to ouabain present in the tissue spaces labeled by [(14)C]insulin. Increasing the KCl concentration of the incubation medium reduced the rate of ouabain binding but not the maximal amount bound. In contrast to the low level of ouabain binding to salt glands of ducks maintained on a freshwater regimen, exposure to a salt water diet led to a more than threefold increase in binding within 9-11 days. This increase paralleled the similar increment in Na+-K+-ATPase activity described previously. [(3)H]ouabain binding sites were localized autoradiographically to the folded basolateral plasma membrane of the principal secretory cells. The luminal surfaces of these cells were unlabeled. Mitotically active peripheral cells were also unlabeled. The cell-specific pattern of [(3)H]ouabain binding to principal secretory cells and the membrane-specific localization of binding sites to the nonluminal surfaces of these cells were identical to the distribution of Na+-K+-ATPase as reflected by the cytochemical localization of ouabain-sensitive and K+-dependent nitrophenyl phosphatase activity. The relationship between the nonluminal localization of Na+-K+-ATPase and the possible role of the enzyme n NaCl secretion is considered in the light of physiological data on electrolyte transport in salt glands and other secretory epithelia. 相似文献
8.
Summary An infant exposed to high levels of lead in utero was found to have increased numbers of cells with chromosome breaks in blood samples obtained at 6 weeks and 3 months of life. Later samples did not show significant abnormality. Physical and neurological examinations of the patient up to 18 months of age gave results within normal limits. 相似文献
9.
Angiogenesis is the formation of new blood vessels from pre-existing vasculature. Pathologic angiogenesis in the eye can lead
to severe visual impairment. In our review, we discuss the roles of both pro-angiogenic and anti-angiogenic molecular players
in corneal angiogenesis, proliferative diabetic retinopathy, exudative macular degeneration and retinopathy of prematurity,
highlighting novel targets that have emerged over the past decade. 相似文献
10.
Abbu Zaid Firoz Mohammad Qazi Fariduddin 《Physiology and Molecular Biology of Plants》2020,26(1):25-39
Menthol mint (Mentha arvensis L.) cultivation is significantly affected by the heavy metals like cadmium (Cd) which also imposes severe health hazards. Two menthol mint cultivars namely Kosi and Kushal were evaluated under Cd stress conditions. Impact of plant growth regulators (PGRs) like salicylic acid (SA), gibberellic acid (GA3) and triacontanol (Tria) on Cd stress tolerance was assessed. Reduced growth, photosynthetic parameters, mineral nutrient concentration, and increased oxidative stress biomarkers like electrolyte leakage, malondialdehyde, and hydrogen peroxide contents were observed under Cd stress. Differential upregulation of proline content and antioxidant activities under Cd stress was observed in both the cultivars. Interestingly, low electrolyte leakage, lipid peroxidation, hydrogen peroxide and Cd concentration in leaves were observed in Kushal compared to Kosi. Among all the PGRs tested, SA proved to be the best in improving Cd-stress tolerance in both the cultivars but Kushal responded better than Kosi. 相似文献