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41.
Molecular cytogenetic analysis of a duplication Xp in a male: further delineation of a possible sex influencing region on the X chromosome 总被引:3,自引:0,他引:3
P. Nagesh Rao Kurt Klinepeter William Stewart Rosa Hayworth Robin Grubs Mark J. Pettenati 《Human genetics》1994,94(2):149-153
We describe a male infant with severe mental retardation and autism with a duplication of the short arm of the X chromosome. Chromosome painting confirmed the origin of this X duplication. Molecular cytogenetic analysis with fluorescence in situ hybridization (FISH) identified one copy of the zinc finger protein on the X chromosome (ZFX) and two copies of the steroid sulfatase gene (STS), further delineating the breakpoints. Based on cytogenetic and molecular comparisons of cases from the literature of sex-reversal in dup(X),Y patients and our patient, we suggest that a possible secondary sexinfluencing gene involved in the regulation of sex determination or testis morphogenesis is present at the distal Xp21.1 to p21.2 region. 相似文献
42.
Summary We used in vitro growth inhibition assays to demonstrate that synthetic cecropin protein has potent activity against a range of plant pathogenic bacteria. We then prepared transgenic tobacco plants which express cecropin mRNA and protein. We have used Pseudomonas syringae pv tabaci infection of these transgenic tobacco as a model system to evaluate whether the plants which express cecropin protein also have increased tolerance to infection. We found no dramatic difference in disease response between plants which are expressing cecropin protein and control plants which were derived from the transformation with a binary vector which did not carry the gene encoding cecropin protein. 相似文献
43.
The effect of age on the recognition thresholds of three sweeteners: sucrose,saccharin and aspartame
It iS believed that people's sensitivity to taste declines with age but the evidence is inconclusive. This study was designed to test the hypothesis that taste recognition thresholds (TRTs) for sweetness are higher in older than in younger individuals, using groups of 16 younger subjects (18–30) and 16 older subjects (60–85). Three test substances were used: sucrose, aspartame and saccharin. A questionnaire recorded variables which might have affected TRTs, but data failed to show any trend that might have biased the principle variate-age. There was a significant alteration with age of recognition thresholds, at least for sucrose and saccharin. The differences between the groups for the three sweeteners were due to the fact that all the very sensitive subjects were young. None of the older subjects had particularly poor discrimination: all but one had TRTs within the range of younger subjects. Although there are age-related taste changes, they are much less dramatic than commonly occurs with other senses, such as sight and hearing. The findings of this study have implications for institutional catering and the dietary management of older people using non-sugar sweeteners. 相似文献
44.
Robin J. Gouka Wim van Hartingsveldt Roel A. L. Bovenberg Cora M. J. van Zeijl Cees A. M. J. J. van den Hondel Robert F. M. van Gorcom 《Applied microbiology and biotechnology》1993,38(4):514-519
A new transformation system for the filamentous fungus Penicillium chrysogenum is described, based on the use of the homologous acetyl-coenzyme A synthetase (facA) gene as a selection marker. Acetate-non-utilizing (Fac–) strains of P. chrysogenum were obtained by positive selection for spontaneous resistance to fluoroacetate. Among these fac mutants putative facA strains were selected for a loss of acetyl-coenzyme A (CoA) synthetase activity. The facA gene, coding for the enzyme acetyl-CoA synthetase, was isolated from a P. chrysogenum genomic library using synthetic oligonucleotides derived from conserved regions from the corresponding genes of Aspergillus nidulans and Neurospora crassa. Vector pPC2-3, comprising a genomic 6.5 kb PstI fragment, was able to complement P. chrysogenum facA strains with frequencies up to 27 transformants·g–1 DNA. Direct selection of transformants was accomplished using acetate and low amounts (0.001%) of glucose as carbon sources. About 50% of the transformants arose by integration of pPC2-3 DNA at the homologous facA locus and 50% by integration elsewhere in the genome. Determination of the nucleotide sequence of part of the cloned fragment showed the presence of an open reading frame of 2007 nucleotides, interrupted by five putative introns. Comparison of the nucleotide and the amino acid sequence of the facA gene of P. chrysogenum with the facA gene of A. nidulans reveals similarities of 80% and 89%, respectively. The putative introns present in the P. chrysogenum facA gene appear at identical positions as those in the A. nidulans facA gene, but show no significant sequence similarity.
Correspondence to: R. F. M.van Gorcom 相似文献
45.
Structure of the intergenic spacer region from the ribosomal RNA gene family of white spruce (Picea glauca) 总被引:2,自引:0,他引:2
Five genomic clones containing ribosomal DNA repeats from the gymnosperm white spruce (Picea glauca) have been isolated and characterized by restriction enzyme analysis. No nucleotide variation or length variation was detected within the region encoding the ribosomal RNAs. Four clones which contained the intergenic spacer (IGS) region from different rDNA repeats were further characterized to reveal the sub-repeat structure within the IGS. The sub-repeats were unusually long, ranging from 540 to 990 bp but in all other respects the structure of the IGS was very similar to the organization of the IGS from wheat, Drosophila and Xenopus. 相似文献
46.
Robin W. Renaut 《Hydrobiologia》1993,267(1-3):75-98
Benthic microbial mats are common in the alkaline hydromagnesite-magnesite playa lakes of Interior British Columbia. Four main zones are recognized based on mat morphology that can be related to the type and duration of wetting. From the basin margin toward the playa centre they are: (i) vegetated hummocky ground; (ii) polygonal hummocky ground; (iii) low-domal and stratiform mats, and (iv) laterally continuous and pustular mats. Mats in peripheral mudflats are commonly mineralized by hydromagnesite, mostly precipitated by capillary evaporation of shallow groundwaters. Mats forming in the ephemeral lake tend to have lower carbonate content.Although widespread, the mats are poorly preserved in the Holocene sedimentary record. Underlying sediments are commonly weakly bedded, disturbed or massive. Desiccation, dehydration, wetting-drying cycles, and grazing by invertebrates cause fragmentation of mats at the surface, facilitating erosion. Cryogranulation, interstitial mineral precipitation, vesiculation, bioturbation, compaction, and volume changes associated with diagenesis, disrupt and destroy lamination in the upper few centimetres. Most surviving organic matter is lost by early microbial degradation. 相似文献
47.
Global change may have profound effects on soil nitrogen (N) cycling that can induce positive feedback to climate change through increased nitrous oxide (N2O) emissions mediated by nitrification and denitrification. We conducted a meta-analysis of the effects of elevated CO2 on nitrification and denitrification based on 879 observations from 58 publications and 46 independent elevated CO2 experiments in terrestrial ecosystems. We investigated the effects of elevated CO2 alone or combined with elevated temperature, increased precipitation, drought, and N addition. We assessed the response to elevated CO2 of gross and potential nitrification, potential denitrification, and abundances of related functional genes (archaeal amoA, bacterial amoA, nirK, nirS, and nosZ). Elevated CO2 increased potential nitrification (+28%) and the abundance of bacterial amoA functional gene (+62%) in cropland ecosystems. Elevated CO2 increased potential denitrification when combined with N addition and higher precipitation (+116%). Elevated CO2 also increased the abundance of nirK (+25%) and nirS (+27%) functional genes in terrestrial ecosystems and of nosZ (+32%) functional gene in cropland ecosystems. The increase in the abundance of nosZ under elevated CO2 was larger at elevated temperature and high N (+62%). Four out of 14 two-way interactions tested between elevated CO2 and elevated temperature, elevated CO2 and increased precipitation, and elevated CO2 and N addition were marginally significant and mostly synergistic. The effects of elevated CO2 on potential nitrification and abundances of bacterial amoA and nirS functional genes increased with mean annual temperature and mean annual precipitation. Our meta-analysis thus suggests that warming and increased precipitation in large areas of the world could reinforce positive responses of nitrification and denitrification to elevated CO2 and urges the need for more investigations in the tropical zone and on interactive effects among multiple global change factors, as we may largely underestimate the effects of global change on soil N2O emissions. 相似文献
48.
Variation in tooth crown morphology plays a crucial role in species diagnoses, phylogenetic inference, and the reconstruction of the evolutionary history of the primate clade. While a growing number of studies have identified developmental mechanisms linked to tooth size and cusp patterning in mammalian crown morphology, it is unclear (1) to what degree these are applicable across primates and (2) which additional developmental mechanisms should be recognized as playing important roles in odontogenesis. From detailed observations of lower molar enamel–dentine junction morphology from taxa representing the major primate clades, we outline multiple phylogenetic and developmental components responsible for crown patterning, and formulate a tooth crown morphology framework for the holistic interpretation of primate crown morphology. We suggest that adopting this framework is crucial for the characterization of tooth morphology in studies of dental development, discrete trait analysis, and systematics. 相似文献
49.
Zhi Jian Yu Changbae Jin Robin William Rockhold Beth Hoskins Ing Kang Ho 《Neurochemical research》1993,18(11):1203-1209
Wistar-Kyoto and spontaneously hypertensive rats received i.v. infusions of cocaine hydrochloride (60 mg/kg per day) for 3, 7, and 14 days, or saline for 7 days. Acute cocaine challenge (40 mg/kg, s.c.) was given to treated and control rats 24 hr after the termination of each infusion period. There were no strain differences in brain levels of cocaine during cocaine infusion, nor after cocaine challenges. There were no strain differences in resting levels of [3H]dopamine release. Release of [3H]dopamine decreased in nuclei accumbens of 7- and 14-day cocaine-infused animals. Release of [3H]dopamine was maximal in both brain regions 2 hr after acute cocaine challenge. After 14 days of cocaine infusion, cocaine challenge in both strains reduced [3H]dopamine release in the nucleus accumbens, but not in the striatum; the reduction being greater in Wistar-Kyoto rats. The behavioral tolerance which accompanies similar cocaine infusion regimens may be related to striatal tolerance to cocaine-induced dopamine release. 相似文献
50.
Paul L. Black Hamblin Phillips Henry R. Tribble Robin Pennington Mark schneider James E. Talmadge 《Cancer immunology, immunotherapy : CII》1993,37(5):299-306
The mechanism of therapeutic activity for recombinant murine interferon-(rMu IFN) in the treatment of metastatic disease was investigated by comparing effector cell augmentation with therapeutic activity in mice bearing experimental lung metastases (B16-BL6 melanoma). Effector cell functions in spleen, peripheral blood, and lung (the tumor-bearing organ) were tested after 1 week and 3 weeks of rMu IFN administration (i.v. three times per week). Natural killer (NK), lymphokine-activated killer (LAK), cytolytic T lymphocyte (CTL) activities against specific and nonspecific targets, and macrophage tumoristatic activity were measured. rMu IFN demonstrated immunomodulatory activity in most assays of immune function. The optimal therapeutic protocol of rMu IFN (2.5×106 U/kg, three times per week) prolonged survival and decreased the number of pulmonary metastatic foci. This therapeutic activity was correlated with specific CTL activity from pulmonary parenchymal mononuclear cells (PPMC), but not from spleen or blood. Macrophage tumoristatic activity in PPMC also correlated with therapeutic activity, but activity in alveolar macrophages did not. However, therapeutic activity did not correlate with NK or LAK activity at any site. These results demonstrate that the optimal therapeutic protocol is the same as the optimal immunomodulatory dose for pulmonary CTL and macrophage activities. Furthermore, while immunological monitoring may help to optimize treatment protocols, current monitoring procedures that use readily accessible sites, particularly peripheral blood, may not accurately predict the therapeutic efficacy of biological response modifiers in clinical trials.By acceptance of this article, the publisher or recipient acknowledges the right of the US. Government to retain a nonexclusive, royalty-free license in and to any copyright covering the articleThis research was sponsored by the DHHS, under contract N01-23910 with Program Resources Inc. The contents of this publication do not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government 相似文献