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The cDNA cloning and molecular evolution of reptile and pigeon lactate dehydrogenase isozymes 总被引:1,自引:0,他引:1
The cDNAs encoding lactate dehydrogenase isozymes LDH-A (muscle) and LDH-B
(heart) from alligator and turtle and LDH-A, LDH-B, and LDH-C (testis) from
pigeon were cloned and sequenced. The evolutionary relationships among
vertebrate LDH isozymes were analyzed. Contrary to the traditional belief
that the turtle lineage branched off before the divergence between the
lizard/alligator and bird lineages, the turtle lineage was found to be
clustered with either the alligator lineage or the alligator-bird clade,
while the lizard lineage was found to have branched off before the
divergence between the alligator/turtle and bird lineages. The pigeon
testicular LDH-C isozyme was evidently duplicated from LDH-B (heart), so it
is not orthologous to the mammalian testicular LDH-C isozymes.
相似文献
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Cultures of 12 South African isolates of an undescribedFusarium species resembling but distinct fromF camptoceras were analysed for the presence of diacetoxyscirpenol (DAS), neosolaniol monoacetate (NMA), and T-2 toxin, by capillary gas chromatography utilizing electron capture detection. No DAS or T-2 toxin could be detected in any of the cultures of the isolates. NMA was, however, detected in 10 of the 12 isolates at levels ranging from 310 to 2060 ng/g. The method used, was primarily developed for the determination of DAS and T-2 toxin in fungal cultures and grain samples but was found to be suitable for the coextraction of NMA at an average recovery of 80.8%, with a detection limit in the order of 100 ng/g. Supportive evidence for the presence of the NMA was obtained by capillary gas chromatography / mass spectrometry. Regarded as a relatively rare trichothecene, NMA has never been reported to occur naturally and has previously been shown to be produced by only a fewFusarium strains. 相似文献
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Diel vertical migration (DVM) is a complex and dynamic behaviour against predation because the reaction of migrating organisms to light intensity plays a primary role, but is modified by other factors. In the relatively shallow but thermally stratified Lake Eymir, Daphnia pulex de Geers utilized vertical refugia afforded by the hypolimnion during both day and night. Differences in general vulnerability to fish predation determined the differences in their mean residence depths (MRDs) of different population categories such as most conspicuous and vulnerable individuals of adult with eggs inhabited the deepest depth, whereas juveniles stayed close the thermocline. In late spring, profoundly high amplitude of displacement within the hypolimnion, probably due to the hypolimnion being well-lit and relatively well-oxygenated for the fish and rather unsafe for the large-sized daphnids, was recorded. Therefore, the large-sized daphnids daytime refuge was close to the bottom whereas at night they moved upward to benefit from warmer water temperature along with food availability in the presence of fish predation but still remained below the thermocline. In summer, the insignificant amplitude of the hypolimnetic, which later became epilimnetic, displacements were probably due to the near-anoxic condition found below the thermocline. This might have deterred the fish, thus providing a safer refuge for daphnids in the below thermocline, which afterwards became the above thermocline. Low oxygen availability was regarded as the summer proximate factor. The abundant food and warmer water conditions found in the below/above thermocline also accounted for absence of DVM in summer. Consequently, this study suggests that DVM by Daphnia is an adaptation that is plastic to changing environmental conditions. 相似文献
90.
We describe here a new method for specific staining of mast cells using ferroin. Different hamster tissues were fixed in 4% formalin and processed for paraffin embedding. Sections were stained with hematoxylin followed by ferroin acidified with 2.5 N sulfuric acid to pH 4.0. Mast cells stained an intense orange color that contrasted markedly with bluish violet nuclei. High contrast was also observed when ferroin colored sections were counterstained with light green instead of hematoxylin. To evaluate the specificity of the stain, hamster cheek pouch sections were stained with toluidine blue, alcian blue-safranin O, and ferroin. Quantitative evaluation of mast cells stained with the three techniques showed no statistical difference. The simplicity and selectivity of this method is sufficient for image analysis of mast cells. 相似文献