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91.
92.
The untranslated leader of nuclear COX4 gene of Saccharomyces cerevisiae contains an intron. 总被引:4,自引:1,他引:3
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The nuclear gene for subunit IV of cytochrome oxidase (COX4) in Saccharomyces cerevisiae contains a 342 bp intron which is contained entirely within the 5' leader of the message. Splicing of the intron results in removal of several small open reading frames; subsequently, the COX4 AUG becomes the 5' proximal initiation codon. A strain with an rna2- mutation fails to splice mRNA efficiently at restrictive temperature and was used to map the intron splice junctions by RNase protection. Two major mRNA initiation sites were mapped by primer extension of synthetic oligodeoxynucleotides. The splice junctions and internal TACTAAC box conform to consensus sequences previously determined from other yeast introns. One gene for subunit V of cytochrome oxidase (COX5b) has also been shown to contain an intron. The significance of introns in two nuclear genes encoding subunits of cytochrome oxidase is discussed. 相似文献
93.
Cost effectiveness of biofeedback and behavioral medicine treatments: a review of the literature 总被引:1,自引:0,他引:1
C J Schneider 《Biofeedback and self-regulation》1987,12(2):71-92
This paper reviews multicomponent behavioral medicine studies that contain cost-effectiveness and or cost-benefit data relevant to the field of biofeedback and relaxation training, primarily when assisted by biofeedback, with or without stress management, in the treatment of psychosomatic illness and pain. A model for evaluating biofeedback treatment is presented. Cost-effectiveness data concerning reduction in physician visits and/or medication use, decrease in medical care costs to patients, reduction in hospital stays and rehospitalization, reduction of mortality, and enhanced quality of life are reviewed. Evidence suggests that multicomponent behavioral medicine treatments are cost-effective on all dimensions reviewed. Cost/benefit ratios range between 1:2 and 1:5, with a median of 1:4. Evidence that could increase the cost effectiveness of biofeedback is reviewed. 相似文献
94.
We have studied the chromatin structure ofPenicillium chrysogenum. This fungus presents the typical nucleosomal repeat and the core DNA size characteristic of all the eukaryotes. The repeat length (about 180 base pairs) is in the range of those obtained for most fungi (160–180 base pairs) and shorter than in higher eukaryotes. Knowledge aboutP. chrysogenum chromatin structure opens the way to the study of the mechanisms of genetic regulation in this filamentous fungus. 相似文献
95.
Alberto Barros M. Carmo Tavares Sérgio Castedo M. Salomé Pereira M. Purificação Tavares M. Almeida e Costa 《Human genetics》1987,75(4):388-390
Summary A double balanced reciprocal translocation involving four chromosomes, t(1;19;6;14) (1p11; 19p11; 6q25; 14q21), was found in the phenotypically normal husband in a couple referred because of repeated abortions. Reciprocal translocations, t(6;14), had been transmitted by his mother, his father being apparently homozygous for a translocation comprising pairs 1 and 19-t(1;19)(1;19). The genetic consequences of this complex chromosomal rearrangement are analyzed. 相似文献
96.
Fragile sites,chromosome evolution,and human neoplasia 总被引:12,自引:0,他引:12
Rosa Miró Inmaculada Concepción Clemente Carmen Fuster José Egozcue 《Human genetics》1987,75(4):345-349
Summary In a study of the possible relationship between human fragile sites, chromosomal rearrangements related to neoplasia, and chromosome regions involved in evolutionary changes, we have found that 17 fragile sites related to cancer, 15 fragile sites not related to cancer, and 17 non-fragile regions also related to human malignancy correspond or are close to bands involved in rearrangements that have taken place during chromosomal evolution in primates. 相似文献
97.
The effect of different extraction methods on the composition of samples of soluble cuticular lipids (SCL) of Citrus aurantium L. was investigated. The variation of extraction yields, when whole leaves were immersed in solvent, was studied as a function of solvent type and duration of immersion. Cuticular waxes were also quantitatively extracted from isolated cuticular membranes of C. aurantium and their composition was compared to that of samples obtained by the immersion method. Significant differences were observed. Higher carbon number homologues of the aliphatic constituent classes were discriminated against when whole C. aurantium leaves were extracted by immersion. The alkyl ester fraction was almost entirely lacking in extracts from whole leaves. The dependence on carbon chain length of the saturation concentrations in chloroform of major aliphatic SCL constituents was determined. The results are discussed in terms of the major physico-chemical processes involved in the extraction of SCL. 相似文献
98.
Valérie Toulon Hervé Sentenac Jean-Baptiste Thibaud André Soler David Clarkson Claude Grignon 《Planta》1989,179(2):235-241
The effect of HCO
3
-
on ion absorption by young corn roots was studied in conditions allowing the independent control of both the pH of uptake solution and the CO2 partial pressure in air bubbled through the solution. The surface pH shift in the vicinity of the outer surface of the plasmalemma induced by active H+ excretion was estimated using the initial uptake rate of acetic acid as a pH probe (Sentenac and Grignon (1987) Plant Physiol. 84, 1367). Acetic acid and orthophosphate uptake rates and NO
3
-
accumulation were slowed down, while 86Rb+ uptake and K+ accumulation rates were increased by HCO
3
-
. These effects were similar to those induced by 4-(2-hydroxyethyl)-1-piperazineethane sulfonic acid/2-amino-2-(hydroxymethyl)-1,3-propanediol (Hepes-Tris). They were more pronounced when the H+ excretion was strong, were rapidly reversible and were not additive to those of Hepes-Tris. The hypothesis is advanced that the buffering system CO2/H2CO3/HCO
3
-
accelerated the diffusion of equivalent H+ inside the cell wall towards the medium. This attenuated the surface pH shift in the vicinity the plasma membrane and affected the coupling between the proton pump and cotransport systems.Abbreviations FW
fresh weight
- Hepes
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- Jaa
acetic acid influx
- JK
+
K+ influx
- JPi
orthophosphate influx
- Mes
2-(N-morpholino)ethanesulfonic acid
- pCO2
CO2 partial pressure
- Tris
2-amino-2-(hydroxymethyl)-1,3-propanediol 相似文献
99.
Regulation of intracellular pH by a neuronal homolog of the erythrocyte anion exchanger 总被引:23,自引:0,他引:23
We have isolated AE3, a novel gene expressed primarily in brain neurons and in heart. The predicted AE3 polypeptide shares a high degree of identity with the anion exchange and cytoskeletal binding domains of the erythrocyte band 3 protein. Expression of AE3 cDNA in COS cells leads to chronic cytoplasmic acidification and to chloride- and bicarbonate-dependent changes in intracellular pH, confirming that this gene product is an anion exchanger. Characterization of an AE3 mutant lacking the NH2-terminal 645 amino acids demonstrates that the COOH-terminal half of the polypeptide is both necessary and sufficient for correct insertion into the plasma membrane and for anion exchange activity. The NH2-terminal domain may play a role in regulating the activity of the exchanger and may be involved in the structural organization of the cytoskeleton in neurons. 相似文献
100.
Peter Kaastrup René J. M. Stet Albert J. Tigchelaar Egbert Egberts Willem B. van Muiswinkel 《Immunogenetics》1989,30(4):284-290
In this study, experiments are described that were designed to investigate whether fish have an immune regulatory systems
similar to the major histocompatibility complex (MHC) in higher vertebrate species. From combinations of gynogenetic carp
showing either slow of fast rejection of skin transplants, the latter were chosen for alloantiserum production by hyperimmunization
with peripheral blood leucocytes. The resulting alloantisera were analyzed for hemagglutinating reactivity with gynogenetic
siblings and proved to be operationally monoscpecific in absorption experiments. The serologically determined carp erythrocyte
specificites were shown to correspond to two codominantly expressed allelic products of a single locus and were designated
K1 and K2, respectively. Flow cytometer analysis revealed that the same products are also present on leucocytes from peripheral
blood, thymus, spleen, and pronephros.K1-andK2-homozygous second-generation gynogenetic siblings were used to study the histocompatibiligy nature of the K locus products.
Skin transplants between K-allogeneic gynogenetic siblings were rejected significantly faster than within K-syngeneic combinations.
Taken together, these data suggest that theK locus incorporates MHC class I-like characteristics. 相似文献