The Wolf-Hirschhorn syndrome (WHS) is caused by a partial deletion in the short arm of chromosome 4 band 16.3 (4p16.3). A unique-sequence human DNA probe (39 kb) localized within this region has been used to search for sequence homology in the apes' equivalent chromosome 3 by FISH-technique. The WHS loci are conserved in higher primates at the expected position. Nevertheless, a control probe, which detects alphoid sequences of the pericentromeric region of humans, is diverged in chimpanzee, gorilla, and orangutan. The conservation of WHS loci and divergence of DNA alphoid sequences have further added to the controversy concerning human descent. 相似文献
The Rb1 gene has been implicated with retinoblastoma and is located on human Chromosome (Chr) 13q14.2. A unique sequence human Rb1 cosmid DNA probe has been used to localize this region on apes' Chr 14 by the FISH technique. The conservation of the Rb1 gene in higher primates at the corresponding equivalent chromosome locus (14q14) of the human may serve as a phylogenetic
marker to further trace the evolutionary pathway of human descent.
Received: 2 February 1996 / Accepted: 9 April 1996 相似文献
The developing brine shrimp, Artemia salina, nauplius is explored as a new model for the study of the biogenesis of the cation transport enzyme, (Na+ + K+)-activated adenosine triphosphatase [(Na, K)-ATPase]. (Na, K)-ATPase activity develops from undetectable levels in preemergent cysts (embryos prior to 12 hr of development) to very high levels in the nauplius after 40 hr of incubation in sea water [Conte, F. P., Droukas, P. C., and Ewing, R. D. 1977). J. Exp. Zool.202, 339], then declines between 44 and 72 hr. Similar ontogenic patterns of enzyme activity development are observed for Mg-ATPase, 5′-nucleotidase, glucose-6-phosphatase, NADH oxidase (rotenone insensitive), and cytochrome oxidase. However, these enzymes show measurable activity in the early cyst stage, and the points at which the activity increases and then reaches a maximum are usually different from those of the (Na, K)-ATPase. These enzyme ontogeny studies demonstrate that membrane differentiation is extensive during the period in naupliar development when (Na, K)-ATPase activity appears, and that the appearance of specific enzymes is asynchronous during embryogenesis. Pulse-chase experiments with NaH14CO3 show an increase in the specific radioactivity of the partially purified (Na, K)-ATPase which is maximum when the label is administered at 12–18 hr after the initiation of development. At this time the specific radioactivity increases with purity of the enzyme, whereas in earlier pulse periods the specific radioactivity is higher in the more crude enzyme fractions, suggesting that preferential synthesis of the (Na, K)-ATPase occurs between 12 and 18 hr. Radioactivity is found in the subunits of the partially purified (Na, K)-ATPase isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and is maximum for the 12- to 18-hr pulse experiment. These pulse-chase experiments demonstrate that the large increase in (Na, K)-ATPase activity is due to de novo synthesis and establish that the brine shrimp is a workable new model for the study of the biogenesis of the (Na, K)-ATPase. 相似文献
Summary Some aspects of spermiogenesis have been studied in the testis of the teiid lizard Cnemidophorus lemniscatus lemniscatus by electron microscopy. Shortly after the acrosomal vesicle is lodged in a nuclear concavity of the spermatid, a dense granule differentiates in the center of the subacrosomal space. It is cone-shaped and shows a longitudinal striation. Its base applies to the acrosomal membrane and, through this, to the acrosomal granule. Its rounded vertex causes a depression of the nuclear membranes which, initially juxtaposed, separates at this point to form a vesicle. The granule develops and becomes a rod when spermiogenesis is advanced and the subacrosomal space has taken the form of a secondary cap. The rod is cylindrical, retains its original striation and has a convex acrosomal end. It encloses the vesicle formed by the nuclear envelope in its base and follows the apex of the nucleus. Meanwhile, the acrosomal granule loses its identity and the acrosomal cap is filled with a dense substance, in which a fringe of translucent material differentiates. This fringe lies in the dorsal and apical margins of the acrosome and is incompletely divided by longitudinal crests of the dense acrosomal substance. A projection of the Sertoli cell forms an accessory cap which envelops the acrosome and is in turn covered by the cytoplasm of the spermatid, constituting an intricate association. Two reflex membranes underlie the plasmalemma in the outer surface of the projection of the Sertoli cell. They are continuous with one another at their ends and with the cell membrane in the edge of pores. In the peripheral cytoplasm of the spermatid facing the accessory cap, numerous microtubules run longitudinally. By means of thin membranes some are interconnected or connected with the plasmalemma, from which they seem to originate.This research forms part of project N. 31.26.S1-0244 supported by the Consejo Nacional de Investigaciones Científicas y Tecnológicas 相似文献
Production of 2,3-butanediol (2,3-BD) by Pantoea agglomerans strain BL1 was investigated using soybean hull hydrolysate as substrate in batch reactors. The cultivation media consisted of a mixture of xylose, arabinose, and glucose, obtained from the hemicellulosic fraction of the soybean hull biomass. We evaluated the influence of oxygen supply, pH control, and media supplementation on the growth kinetics of the microorganism and on 2,3-BD production. P. agglomerans BL1 was able to simultaneously metabolize all three monosaccharides present in the broth, with average conversions of 75% after 48 h of cultivation. The influence of aeration conditions employed demonstrated the mixed acid pathway of 2,3-BD formation by enterobacteria. Under fully aerated conditions (2 vvm of air), up to 14.02 g L−1 of 2.3-BD in 12 h of cultivation were produced, corresponding to yields of 0.53 g g−1 and a productivity of 1.17 g L−1 h−1, the best results achieved. These results suggest the production potential of 2,3-BD by P. agglomerans BL1, which has been recently isolated from an environmental consortium. The present work proposes a solution for the usage of the hemicellulosic fraction of agroindustry biomasses, carbohydrates whose utilization are not commonly addressed in bioprocess.
Abstract Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeats (ISSR) markers were employed to examine samples from Quercus cerris, Q. suber and Q. crenata in order to test the hypothesis of the hybrid origin of Q. crenata from Q. cerris and Q. suber in a part of its distribution area where the two putative parents do not overlap at present. Leaves from 21 Q. crenata and 37 Q. cerris individual trees were collected at natural sites in northern Italy, where Q. suber is currently lacking; 21 Q. suber and six Q. crenata plants from central Italy were also analysed. Results from Unweighted Pair Group Method with Arithmetic mean (UPGMA) analysis and principal component analysis (PCA) implied that exchange of neutral markers has been considerable between the three species, while differences in morphological characters have remained comparatively stable. The Mantel test indicated low correlation between RAPD- and ISSR-based similarity matrices, showing that the two screening techniques reveal unrelated estimates of genetic relationships. Hybrid indices computed for both markers displayed an intermediate position of Q. crenata individuals between the two putative parents shifted toward Q. cerris. Results from the present study corroborate the hypothesis of a hybrid origin for Q. crenata occurring in northern Italy, and suggest asymmetrical backcrossing with Q. cerris acting as the recurrent parent. 相似文献
Medical centers worldwide report an increased frequency of Hashimoto''s thyroiditis (HT) and thyroid cancer (TC), two environmentally influenced diseases. In Sicily, data on HT are available for the province of Messina (1975–2005); data on TC are available for the whole island (2002–2004), with the volcanic province of Catania having the highest incidence.
Objective
To replicate in Catania, on comparable years, the HT data of Messina.
Design, Methods, Setting
Review of the clinical records of patients in years 1995–2005 to compare presentation and yearly changes of HT. During 1995–2005, records were computer stored in the Endocrine Divisions of the University Hospitals of Catania and Messina, two tertiary referral centers.
Results
Catania is outnumbered by Messina (742 vs. 3,409 HT patients). Similar were the linear increase in the yearly number of HT patients, rates of thyroid dysfunctions though with different proportions of subclinical and overt hypothyroidism, and rates of positiveness for TgAb or TPOAb. Different were age and its yearly trend; gender distribution and rates of the sonography variants, though yearly trends were similar.
Conclusion
The HT epidemics is smaller in Catania, with changes in presentation overlapping partially those in Messina. Whatever environmental factors might be involved, they (and/or their intensity) were not necessarily the same in these provinces. Intriguingly, the expected number of TC in HT patients with thyroid nodules in Catania is congruent with that of the general population of this province, but it is far less than in the Messina province. Thus, TC and HT incidences could be influenced by distinct environmental factors. 相似文献
The aim of the present study was to simultaneously assess several potential predictors of outcome (co-morbidity, previous and in-hospital treatment, radiologic Brixia score) in patients with COVID-19.This retrospective cohort study included 258 consecutive patients with confirmed COVID-19 admitted to a medical ward at Montichiari Hospital, Brescia, Italy from February 28th to April 30rd, 2020. Patients had SARS-CoV-2 related pneumonia with respiratory failure, and were treated with hydroxychloroquine and lopinavir plus ritonavir. In some patients, additional treatment with tocilizumab, dexamethasone and enoxaparin was adopted. Outcomes (death or recovery) were assessed at the end of the discharge period or at the end of the follow-up (August 2020).During hospitalization, 59 patients died, while 6 died after discharge. The following variables were demonstrated to be associated with a worse prognosis: Radiologic Brixia score higher than 8, presence at baseline of hypertension, diabetes, chronic obstructive pulmonary disease, heart disease, cancer, previous treatment with ACE-inhibitors or anti-platelet drugs. Anticoagulant treatment during hospital admission with enoxaparin at a dose higher than 4000 U once daily was associated with a better prognosis.In conclusion, our study demonstrates that some co-morbidities and cardiovascular risk factors may affect prognosis. The radiologic Brixia score may be a useful tool to stratify the risk of death at baseline. Anticoagulant treatment with enoxaparin might be associated to a clinical benefit in terms of survival in patients with COVID-19. 相似文献