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121.
Populations of the parthenogenetic moth Ectoedemia argyropeza (Lepidoptera, Nepticulidae) were studied for their clonal composition. Clones were characterized by 6 polymorphic enzyme loci. In a geographic survey 32 clones were observed among 812 individuals. Two clones were predominant, together they explained over 75% of the total variation. Relationships among clones hinted at a monophyletic origin of the species. Analysis of the life cycle and population structure indicated that E. argyropeza is a very sedentary species, with bottlenecks, drift, and passive migration as important population genetical factors moulding the variation.  相似文献   
122.
123.
Restriction fragments analysis of DNA from mouse-hamster somatic-cell hybrid clones revealed that a mouse gamma crystallin cDNA hybridized to genomic sequences located on mouse chromosome 1. Identification of restriction fragment length polymorphisms (RFLPs) in the gamma crystallin sequences of inbred strains of mice permitted the further localization of the gamma crystallin genes (Cryg) to the proximal region of chromosome 1 closely linked to the loci encoding isocitrate dehydrogenase (Idh-1), a low molecular weight (LM) crystallin protein polymorphism (Len-1), and fibronectin (Fn-1). A single recombinant was observed betweenLen-1 and an RFLP in the gamma crystallin gene family, consistent with the hypothesis thatLen-1 is one of the several structural loci encoding gamma crystallin genes.Len-1 is probably located on the centromeric end of theCryg gene family. Linkage ofIdh-1, Cryg, andFn-1 in mice extends the syntenic relationship of those loci to the human, bovine, and rodent genomes and may define a chromosomal region that is generally conserved among mammals. The map position ofCryg, near the eye lens obsolescence (Elo) locus, was confirmed by the discovery that the restriction fragment patterns of gamma crystallin sequences differed between strain C3H/HeJ and the congenic anophthalmic mutant strain, C3H.Elo. Therefore, the gamma crystallin genes were contransferred with the mutantElo gene in the derivation of C3H.Elo. The results establish that LEN-1 is a marker for the gamma crystallin gene family, position the gamma crystallin gene family relative to other markers on mouse chromosome 1, and provide additional evidence that theElo mutation is encoded at a locus closely linked to the gamma crystallin gene cluster. This study found no evidence of recombination hot spots within the gamma crystallin gene cluster.  相似文献   
124.
Recombinational and deletion mapping of electrophoretic variants of the glutamine synthetase I isozyme (GSI) in Drosophila melanogaster locates the gene in the 21B region on the second chromosome. We have conducted a genetic analysis of the region extending cytologically from 21A to 21B4-6. Recessive lethal mutations were generated by ethyl methanesulfonate (EMS) and ethyl nitrosourea (ENU) mutagenesis and by hybrid dysgenesis (HD). These lethals fall into seven functional groups, which were partially ordered by complementation with cytologically defined deficiencies of this region generated by hybrid dysgenesis. Two of the EMS- and two of the ENU-induced lethals fulfill biochemical criteria expected for null alleles of the GSI gene.  相似文献   
125.
The nervous systems of the turbellarians Microstomum lineare and Polycelis nigra and of the cestodes Diphyllobothrium dendriticum and Schistocephalus solidus were studied by means of the peroxidase-antiperoxidase (PAP) immunocytochemical method, with the use of antisera to the neuropeptides FMRF-amide, vasotocin, leu-enkephalin, met-enkephalin, neurotensin, somatostatin, and VIP, and to the bioamine serotonin. Anti-FMRF-amide positive perikarya and fibers occurred in all species, while the occurrence of the vertebrate brain-gut peptides and serotonin varied between the species. Anti-somatostatin and anti-VIP gave a negative result. Anti-FMRF-amide and anti-vasotocin positive immunoreactivity was found in the brain and gut of M. lineare, and in the CNS and the peripheral nerve net of the cestodes. We suggest that the brain-gut peptides of free-living flatworms act on the subtegumental region in the cestodes, which lack a gut but absorb their nutrients directly through the tegument.  相似文献   
126.
Siliceous remains from Miocene lacustrine sediments near Libros (Teruel, Spain) are studied. Most of them are sponge spicules and may be assigned to Ephydatia fluviatilis. Some chrysophycean cysts and several diatom genera (Melosira, Cyclotella, Fragilaria, Navicula, Pinnularia, and Cymbella) have also been found.  相似文献   
127.
The relationships between presynaptic acetylcholinesterase (AChE) and high-affinity choline uptake (HACU) were investigated using a monolayer of rat cortex synaptosomes in superfusion conditions. The following sets of experiments were performed: determination of [3H]choline ([3H]Ch) uptake during superfusion with [3H]Ch; determination of [3H]Ch uptake during superfusion with acetylcholine (ACh) tritiated in the Ch moiety; evaluation of ACh hydrolysis during superfusion with ACh labelled in the acetate moiety; and comparison of the uptake of [3H]Ch generated by hydrolysis of [3H]ACh with that occurring during superfusion with [3H]Ch. Intact ACh was not taken up by superfused synaptosomes. The uptake of [3H]Ch during superfusion with 1 or 0.1 microM [N-methyl-3H]ACh was two-thirds of that occurring during superfusion with the same concentrations of [3H]Ch. The amount of [3H]Ch produced by hydrolysis during 16 min of superfusion was 1/25 of the amount passing through the synaptosomal monolayer during 16 min of superfusion with [3H]Ch. The results indicate that presynaptic AChE and HACU are located in close proximity to each other on the cholinergic terminal membrane, an observation suggesting the possibility of a functional coupling between the two mechanisms.  相似文献   
128.
Summary Our field surveys conducted in 10 Hungarian grape producing areas have revealed that the nutrient contents of vine leaves of different grape varieties were closely correlated with the EUF-nutrient contents of different soil types with different contents of clay. Resulting from these relationships the following EUF-nutrient values are considered as required for optimal nutrition of the vine-stock to attain grape yields of 10–12 t/ha in the areas under investigation:  相似文献   
129.
A combined method is described for the determination of various metabolites from a single tissue sample of the brain. It comprises a quick inactivation of cerebral enzymes by microwave irradiation, easy separation of the desired brain regions, and perchloric acid extraction of tissue substances, which are assayed either by specific enzymatic techniques or by HPLC with electrochemical detection. The obtained values of most energy and neurotransmitter metabolites in the brain are in agreement with those reported using other methods. However, this technique, in contrast to the brain freezing in vitro or freeze-blowing, provides a more efficient procedure for rapid arrest of cerebral metabolism even in the deep brain structures and is therefore suitable for detection of early changes particularly those occurring in experimental pathological conditions such as ischemia.  相似文献   
130.
Blood glucose, insulin and prolactin concentrations were determined before and after sulpiride injection (50 mg i.m.) in 20 non-insulin-dependent diabetic patients (10 with retinopathy and 10 without evidence of retinal damage) and 10 subjects with normal glucose tolerance. Prolactin response to sulpiride was significantly higher in diabetics than in controls (at 20 min., p less than 0.01; at 30 and 60 min., p less than 0.005; at 90 min., p less than 0.01; at 120 min., p less than 0.05). The sulpiride induced hyperprolactinemia did not influence blood glucose and plasma insulin levels in controls as well as in diabetic patients. Prolactin response to sulpiride was the same in diabetics with and in those without retinal changes. We conclude that acute hyperprolactinemia seems to have no influence on glucose homeostasis in normal and non insulin-dependent diabetic subjects.  相似文献   
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