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21.
This paper reports a case of XY gonadal dysgenesis in two sisters. Both patients presented an eunochoid female phenotype with normal external genitalia. At laparotomy, the elder sister was found to have bilateral gonadoblastoma. Cytogenetic studies, which included G and C banding and in situ hybridization, showed that the patients had an apparently normal 46, XY karyotype. PCR analyses revealed absence of the conserved portion (HMG box) of the SRY gene and of the Y chromosome pseudoautosomal boundary region sequence in both patients. The presence of the ZFY sequence was detected by Southern hybridization in the two affected sisters. The patients' father (46, XY, no mosaicism detected in peripheral blood lymphocytes) was positive for SRY and ZFY sequences. The occurrence of gonadoblastoma is discussed in terms of the genetic factors that may lead to tumor development.  相似文献   
22.
Some behavioral and physical defenses of Lymantria dispar (L.) pupae are described. It was found that the layer of webbing surrounding pupae significantly reduced oviposition rates in the pupal parasitoid Brachymeria intermedia (Nees) (Hymenoptera, Chalcididae). The reasons for this reduction and consequent parasitoid responses were investigated. The role of these behaviors in this host parasitoid relationship are discussed.
Résumé Le comportement défensif des chrysalides de Lymantria dispar L. consiste en cambrage et en tournoiement. Les chrysalides encoconées étaient plus sensibles aux stimuli tactiles que celles qui ont été extraites des cocons. Brachymeria intermedia Nees avait moint de succès dans l'insertion complète de la tarière dans des chrysalides encoconées qu'extraites, car elles devenaient empêtrées dans le cocon quand la chrysalide se défendait. Il y avait différentes réponses du parasitoïde à l'empêtrement. Elles comprenaient l'abandon de l'attaque par un départ, la remise en selle sur l'hôte, la morsure à travers les fils du cocon, l'attaque d'un hôte voisin, le repos ou la toilette. Les taux d'insertion de la tarière pouvaient être augmentés par l'élimination artificielle de quelques fils. La durée des opérations était plus courte sur les chrysalides plus petites. La discussion a porté sur l'importance de ces comportements sur les relations de ces parasitoïdes avec leurs hôtes.
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23.
Two hundred subjects with insulin-dependent (type I) diabetes mellitus (IDDM) were typed for HLA-B, HLA-DR, and properdin factor B (Bf). HLA and Bf antigen and haplotype frequencies in subjects were compared with control frequencies derived from the 8th HLA Workshop. Frequencies of extended haplotypes (defined by B-Bf-DR alleles on a chromosome) were also contrasted with control frequencies. Significant positive associations between IDDM and HLA-B8, DR3, DR4, BfS, and BfF1 were confirmed, as were significant negative associations between IDDM and HLA-B7, DR2, DR5, DR7, and BfF. One haplotype (B7-BfS-DR2) exhibited significant negative association, while five haplotypes (B8-BfS-DR3, B8-BfS-DR4, B15-BfS-DR4, B18-BfF1-DR3, and B40-BfS-DR4) exhibited significant positive associations with IDDM. In this sample, 64% of all probands carried at least one of the high-risk haplotypes. In conclusion, the occurrence of five "high-risk" haplotypes associated with IDDM provides evidence for previously undocumented genetic heterogeneity and suggests that possibly more than two HLA-region genes may be involved in IDDM susceptibility.  相似文献   
24.
Summary Analysis of the geographic distribution of acheiropody suggests spread from São Paulo along the São Francisco valley at a rate consistent with current parent-offspring distribution and 20 generations of gene flow.PGL No. 233. This work was supported by Grants GM 17173 from the U.S. National Institutes of Health and Biologicas 79/0482 from São Paulo Research Foundation (FAPESP).  相似文献   
25.
Summary Under a general model the genetic heritability is 0.33 for IgA, 0.34 for IgG and 0.12 for IgM, in a Brazilian population with Chagas' disease. Cultural heritability is much smaller. The analyses suggest that, with respect to family resemblance for immunoglobulins, there is no discrepancy between this sample and those from healthy populations reanalyzed recently (Barbosa et al. 1981).This work was supported by Grants 79/0482 FAPESP (Brazil), 77/2222.1392 CNPq (Brazil) and GM 17173 (Hawaii) with collaboration of the Fundação Instituto Osvaldo Cruz (Bambui, MG). Partly supported by NIH Grants GM 24941 and GM 28719.  相似文献   
26.
The major soluble protein in the lenses of most birds and reptiles is delta-crystallin. In chickens and ducks the delta-crystallin gene has duplicated, and in the duck both genes contribute to the protein in the lens, while in the chicken lens there is a great preponderance of the delta 1 gene product. Purified delta-crystallin has previously been shown to possess the enzymatic activity of argininosuccinate lyase. In order to determine the enzymatic properties of the two duck delta-crystallins their corresponding cDNA molecules were placed in yeast and bacterial expression plasmids. In Saccharomyces cerevisiae, the activity of each crystallin was assessed by transformation of the expression plasmids into a strain deficient for argininosuccinate lyase activity. The ability of the resulting yeast to grow on arginine deficient medium was used as a measure of enzymatic activity. Yeast expressing the duck delta 2-crystallin protein grew rapidly, while those expressing delta 1-crystallin failed to grow. Enzyme activity measurements confirmed the presence of activity in the delta 2-crystallin-expressing yeast, and no detectable activity could be demonstrated in the delta 1-crystallin-expressing yeast. Northern blotting of RNA from the transformed yeast revealed equal levels of mRNA species from the two constructs. For further analysis, the delta 2-crystallin cDNA was placed in the bacterial expression plasmid, pET-3d. The delta 2-crystallin protein produced in Escherichia coli was purified to homogeneity and analyzed to determine the kinetic properties. A Km of 0.35 mM was determined for argininosuccinate and a Vm of 3.5 mumols/min/mg was determined. These data demonstrate that, following duplication of the primordial argininosuccinate lyase gene, one of the genes maintained its role as an enzyme (delta 2-crystallin) while also serving as a crystallin and the other has evolved to specialize as a structural protein in the lens (delta 1-crystallin), presumably losing most or all of its catalytic capacity.  相似文献   
27.
Process conditions for the acid hydrolysis of pine hemicellulose and cellulose have been described which provide a biocompatible sugar solution. By using an improved strain of recombinant Escherichia coli, strain KO11, hydrolysates supplemented with yeast extract and tryptone nutrients were converted to ethanol with an efficiency of 85% to over 100% on the basis of monomer sugar content (approximately 72 g/liter) and with the production of 35 g of ethanol per liter in 48 h. In the process described, approximately 347 liters of ethanol could be produced per dry metric ton of lignocellulose.  相似文献   
28.
Following cell fractionation in sucrose density gradients, plasma membrane Mg(2+)-ATPase from Pachysolen tannophilus was studied. The ATPase displayed an apparent Km for ATP of 1.42 mM and was inhibited by high concentrations of Mg2+. The inhibitory effects of ethanol, 1-propanol, 1-butanol, and benzyl alcohol on Mg(2+)-ATPase were evaluated, and the concentration of each alcohol that inhibited ATPase activity by 50% (IC50) was determined. The IC50 decreased as the chain length of the alcohol increased. Moreover, the IC50 for ATPase activity was similar to the IC50 for growth rate, suggesting an association between impaired growth and ATPase inhibition. Almost complete inhibition of ATPase activity occurred at temperatures approaching 60 degrees C, and the optimal temperature was around 44 degrees C for ATPase from both control and ethanol-treated cells. Inclusion of 50 mM MgCl2 or CaCl2 in the medium did not rescue cells from the deleterious effects of ethanol.  相似文献   
29.
Summary Paraganglion-like structures (PLS) containing chromaffin-positive cells have been reported to be present in the adult human heart. The present work was initiated in order to evaluate the densitity of these structures in the interatrial septum and to study the presence of immunoreactivity of their cells to NSE and PGP 9,5 antibodies, two neuroendocrine markers. Six hundred 6-m paraffin serial sections were obtained from the upper third of the interatrial septum from six adult human hearts. From 2 to 12 paraganglia were found in each case, and their principal cells stained positively with NSE and PGP 9,5 antibodies. Depending on how these PLS related to other cardiac structures, four different types were identified: Type I — True paraganglia (located adjacent to ganglia or nerve fibers); Type II — Free paraganglia (immersed in the interatrial adipose tissue, without evident connection to other structures); Type III — Intraganglionic paraganglia (located within the nervous ganglia); Type IV — Intramyocardic paraganglia (small nests of immunoreactive cells closely related to myocardiocyte bundles). These cardiac paraganglia, which probably belong to the visceral-autonomic group, may have a role in the regulation of the cardiac function and in the adaptive mechanisms of the heart. Its is also possible that they originate functioning and non-functioning tumours.Work supported by grants from FINEP and CNPq (Brazil)  相似文献   
30.
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