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1.
We compared 609 haplotypes carrying the idiopathic hemochromatosis allele with 475 control haplotypes. Four haplotypes were more frequent in hemochromatosis: A3, B7 (actually A3, CW., B7, Bfs, DR2); A3, B14 (actually A3, CW., B14, BfF, DRW6); A11, B35; and A11, B5. The linkage disequilibrium for A3, B7 and A3, B14 (and probably also for A11, B5) was undeniably stronger in hemochromatosis than in controls. Two haplotypes--A3, B12 and A3, B15--were more frequent in hemochromatosis, without linkage disequilibrium. Four haplotypes in linkage disequilibrium in hemochromatosis--i.e., A2, B12; A1, B8; A9, B7; and A29, B12--were also found to have the same frequency and strength of linkage in controls. The dual observation (1) that haplotypes carrying A3 without either B7 or B14 were highly significantly more frequent in hemochromatosis than in controls and (2) that haplotypes carrying B7 or B14 but not A3 had the same frequency in hemochromatosis and controls led to the formal conclusion that only A3 is an independent marker for the hemochromatosis allele, B7 and B14 being involved only owing to the haplotypic mode of marking; the hemochromatosis allele can thus be mapped closer to locus A than to locus B. Our findings fit well with the hypothesis that the hemochromatosis mutation was a rare if not unique event that produced an ancestral HLA marking that was subsequently modified by recombinations and geographical scattering due to migrations.  相似文献   

2.
Introduction – The obesity pandemic is multifactorial. Nutritional, pharmacologic and surgical interventions are limited in reach and efficacy, raising need for new therapeutics. Aims – Characterization of anorexigenic and cognitive effect and central mechanism of action of novel N-acylethanolamide derivatives. Methods – Sabra mice divided to similar experimental groups, injected IP with: oleyl-L-leucinolamide ( 1 A ), linoleyl-L-leucinolamide ( 4 A ), linoleyl-L-valinolamide ( 5 A ), oleyl-oxycarbonyl-L-valinolamide ( 1 B ), oleyl-oxycarbonyl-D-valinolamide ( 2 B ), oleylamine-carbonyl-L-valinolamide ( 3 B ), oleylamine-carbonyl-D-valinolamide ( 4 B ), and oleyl-L-hydroxyvalineamide ( 5 B ). Control group with vehicle. Body weight and food consumption followed for 39 days. Motor activity and cognitive function by open field test and eight-arm maze. Mice sacrificed and mechanism of action investigated by qPCR. The genes analyzed involved in energy balance and regulation of appetite. Catecholamines and serotonin evaluated. Results – Compounds 1 A , 5 A , 1 B – 4 B , caused significant weight loss of 4.2–5.6 % and 5 A , 1 B – 4 B , improved cognitive function following 8 i. p. injections of 1 mg/kg during 39 days, by different mechanisms. 5 A , 3 B and 4 B decreased food consumption, whereas 1 A , 5 A and 2 B increased motor activity. 1 A , 4 A , 1 B and 3 B elevated SIRT-1, associated with survival. POMC upregulated by 1 B and 2 B , CART by 1 B , 2 B and 1 A . NPY and CAMKK2 downregulated by 5 A . 4 B enhanced 5-HT levels. 4 A , 5 A , 1 B , 4 B , 5 B decreased FAAH, showing long lasting effect. Conclusions – These new compounds might be developed for the treatment of obesity and for improved cognitive function.  相似文献   

3.
Blood type A can be classified into subgroups A1, A2, and A1-A2 intermediate on the basis of serological criteria. An excess of A2B over A2, noted in some black populations and among the Japanese, though not in caucasoids, is inconsistent with the classical Mendelian mode of inheritance of the allelic A1 and A2 genes. Characterization of the enzymatic properties of the blood group A and B enzymes in the serum has shown that serological A2B blood of some blacks contains A1 enzyme and a superactive B* enzyme. An excess of A2B found in a study of over 15,000 residents of Hiroshima and Nagasaki prompted investigation of the characteristics of the A and B enzymes in 60 blood samples, 37 from individuals in 13 unrelated families and 23 from other unrelated individuals in the two cities. Among 27 unrelated individuals whose blood types were unequivocally classified serologically as A2B, 15 were confirmed as A2B enzymatically; eight contained A1 and B* enzymes, not A2 or B enzymes, thus being A1B*; two contained Aint and B* enzymes, thus being AintB; and results for the remaining two were ambiguous. Hiroshima differs from Nagasaki in the frequency of the A2B serological type and also in the occurrence of the B* enzyme, Nagasaki having a higher proportion of both. If one considers those cases in which family study was possible, the transmission of the B* enzyme appears to be compatible with the Mendelian mode of inheritance.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

4.
Processing of odor mixtures by neonates is weakly understood. Previous studies showed that a binary mixture of ethyl isobutyrate/ethyl maltol (odorants A/B) blends in newborn rabbits at the 30/70 ratio: Pups would perceive a configural odor in addition to the components' odors. Here, we investigated whether the emergence of this additional odor in AB is determined by specific ratio(s) of A and B. To that goal, we tested whether pups discriminated between AB mixtures with lower (A(-)B, 8/92 ratio) or higher (A(+)B, 68/32) proportion of A. In Experiment 1, pups conditioned to A (or B) responded to A(-)B and A(+)B but not to AB. In Experiment 2, pups responded to A(-)B after learning of A(-) (and to A(+)B after learning of A(+)) but not to AB. In Experiment 3, after conditioning to A(-)B pups responded to A(-) and B (and to A(+) and B after learning of A(+)B) but not or less to AB. In Experiment 4, pups responded to A(-)B and A(+)B after conditioning to AB. These results confirm the configural perception of certain odor mixtures by young organisms and reveal that the proportion of components is a key factor influencing their coding, recognition, and discrimination of complex stimuli.  相似文献   

5.
Using human anti-HLA-A1, A2, B8 and B12 sera the cross reactivity between HLA-antigens A1 and B8 or A2 and B12 respectively was investigated by means of the absorption test. A cross reactivity could be proved to exist between A2 and B12 antigens, but only with an anti-HLA-B12 serum which was adsorbed by A2 positive and B12 negative thrombocytes as well as by A2 negative and B12 positive ones. Thus, the conclusion may be drawn that this serum covers a determinant common to HLA-A2 and B12.  相似文献   

6.
Summary We report the sequence of A/B.L1, a tightly linked pair of genes from the A and B chorion families inBombyx mori. Comparison with the previously characterized A/B.L11 and A/B.L12 pairs from the same species reveals moderate sequence divergence, which is clearly nonuniform. Although the average divergence of A/B.L12 from the other two pairs is more than double that between A/B.L11 and A/B.L1, the ratio differs by more than 30-fold in different DNA regions. One domain of the A gene is highly divergent between A/B.L12 and A/B.L1 or A/B.L11, but essentially invariable in the latter two. In well-aligned DNA segments, nearly all mutated sites (111/112) show variants shared by two of the three sequences, in 42% of the cases between the more distantly related pairs (A/B.L12 and either A/B.L1 or A/B.L11). Eight of the variants shared by distantly related pairs are clustered within 51 bp, suggesting the possibility that they arose through sequence transfers between gene pairs, rather than being primitive or resulting from independent mutations. The short intergenic, putatively regulatory DNa of the developmentally middle A/B.L1 and A/B.L11 pairs resembles that of the late HcA/HcB pairs, particularly in patches that may correspond tocis-regulatory elements.  相似文献   

7.
The two closely related Stat5 (Stat5A and Stat5B) proteins are activated by a broad spectrum of cytokines. However, with the complication of the involvement of Stat5A/5B in stem cell function, the role of Stat5A/5B in the development and function of lymphocytes, especially B cells, is not fully understood. In this study, we demonstrated that Stat5A/5B(-/-) fetal liver cells had severe diminution of B cell progenitors but clearly had myeloid progenitors. Consistently, the mutant fetal liver cells could give rise to hemopoietic progenitors and myeloid cells but not B cells beyond pro-B cell progenitors in lethally irradiated wild-type or Jak3(-/-) mice. Deletion of Stat5A/5B in vitro directly impaired IL-7-mediated B cell expansion. Of note, reintroduction of Stat5A back into Stat5A/5B(-/-) fetal liver cells restored their abilities to develop B cells. Importantly, CD19-Cre-mediated deletion of Stat5A/5B in the B cell compartment specifically impaired early B cell development but not late B cell maturation. Moreover, the B cell-specific deletion of Stat5A/5B did not impair splenic B cell survival, proliferation, and Ig production. Taken together, these data demonstrate that Stat5A/5B directly control IL-7-mediated early B cell development but are not required for B cell maturation and Ig production.  相似文献   

8.
Pregnant mice congenic with C57BL/10 (B10.A, B10.BR, B10.D2, B10.A(2R), B10.A(5R), B10.A(15R), B10.A(1R), B10.A(18R), and B10.OL) were fed Purina Mouse Chow or the same diet plus 200 IU of vitamin A daily. The pregnant dams were sacrificed on the 18th day of gestation and the fetuses were sexed and examined for defects in eye development. It was found that the frequency of microphthalmia and anophthalmia in the female progeny of mice fed Mouse Chow was 7.4-9.2% in B10.A and B10.BR, 4.0-5.5% in B10.A(18R), B10, B10.A(5R), B10.A(1R), B10.A(15R), and B10.A(2R), and 0.8% and 1.4% in B10.D2 and B10.OL mice, respectively. On average, the frequency of these defects in the female progeny was 6.2 times greater than that in males (P less than 0.001). The right eye was 5.8 times more often affected than the left (P less than 0.001). The addition of vitamin A to the diet increased the frequency of these eye abnormalities in all strains, suggesting that this effect is not mediated by loci associated with H-2, as is the case with vitamin A-enhanced cleft palate. The addition of vitamin A to the diet did not affect the ratios of affected males to females, affected right to left eye, or microphthalmia to anophthalmia. The results suggest that there are two loci on chromosome 17, one centromeric to E beta and one telemeric to C4, that interact to determine to some degree the frequency of microphthalmia and anophthalmia.  相似文献   

9.
When Tetrahymena thermophila was incubated with taurolipid A isolated from T. pyriformis NT-1, the exogenously added taurolipid A was deacylated rapidly, and taurolipid B content in the cells was increased. The deacylated taurolipid A (lysotaurolipid A) content reached a maximum early on during incubation, and then declined. Taurolipid B and lysotaurolipid B contents in the cells were increased continuously during the incubation. These observations suggest that lysotaurolipid A was an intermediate for taurolipid B formation. When cells were incubated with lysotaurolipid A, newly formed lysotaurolipid B and taurolipid B were observed. Furthermore, when cells were incubated with lysotaurolipid B, only taurolipid B was newly formed. In contrast, newly formed lysotaurolipid B was observed when cells were incubated with exogenous taurolipid B. From the results, we have postulated the biosynthetic pathway of taurolipid B from exogenous taurolipid A in cells of Thermophila.  相似文献   

10.
The hybrid isozyme of phosphofructokinase, A2B2, was formed by incubation of rabbit muscle enzyme. A4, and rabbit liver enzyme, B4, in the presence of sodium citrate at neutral pH. The enzyme composition of the resulting mixture of A2B2 and the homoprotomeric forms was identical to that found in rabbit adipose tissue extracts. Hybrid formation, which apparently proceeds by way of dimers, can be blocked by fructose-1,6-P2, fructose-6-P, and high concentrations of MgATP. The A2B2 isozyme was separated from A4 and B4 by ion exchange chromatography. The kinetic regulatory properties of A2B2 were compared with those of A4, B4, and a 1:1 mixture of A4 and B4. ATP inhibition of A2B2 was intermediate between that observed with A4 and B4 and was clearly not identical to a simple summing of the effects of A and B subunits. Similar comparisons were made using other phosphofructokinase inhibitors, citrate, 2,3-P2-glycerate, and P-creatine. In each case the observed inhibition was intermediate between the observed with A4 and B4. The existence in a number of tissues of phosphofructokinase A2B2 provides added diversity to the regulatory mechanisms of glycolysis.  相似文献   

11.
Summary F1 plants, monosomic for chromosomes 1A to 7B, from crosses of three lines of Triticum durum var. Khapli with the Chinese series were investigated together with their backcrosses to normal Chinese Spring. The three Khapli lines were designated K1-A, K1-B, and K1-D. Five parameters were analyzed: awn development, glume color, degree of selfing, crossing ability, and seed abortion.Morphological examination of F1 monopentaploid plants revealed that, in the three lines, chromosomes 5A, 1B, 3B, 4B, 5B, and 6B had promotor genes and 2A, 6A, and 2B had inhibitor genes for awn development. Results on glume color suggested the presence of at least three inhibitor genes on 1B, 5B, and 7B, and three promotor genes on 3A, 6A, and 6B chromosomes of Chinese Spring.The first backcross of interspecific hybrids seemed to indicate that some chromosomes (1A, 1B, and 4B) originating from the Khapli lines possessed promotor genes, others (2B and 4A) carried inhibitor genes for seed setting. Similarily, the genetic factor (s) carried by chromosome 5A increased seed abortion whereas those on 2B and 6B reduced it.Self fertility in K1-D hybrids was probably the result of the inhibitor factor (s) on 7A and promotor genes on 3B, 4B, 5B, and 6B chromosomes coming from K1-D.  相似文献   

12.
从黑木耳Auricularia auricula沪3菌株的子实体收集、分离、鉴定得到157株单孢子萌发的单核菌丝体,以其中73株孢子单核体为材料进行交配实验,经过三轮交配反应,结果表明,木耳的交配型符合四极性交配系统的分布规律。根据四种交配反应情况把73株孢子单核体分为四组,并从四组中挑选出B17、B177、B101、B65作为四种交配型的标准菌株;与此同时,从沪3菌株的双核菌丝体制备的原生质体中获得53株原生质体单核体,对这些单核体进行交配,确定出两种亲本交配型,以Y150(A1B1)和Y121(A2B2)作为标准菌株,将两个亲本交配型标准菌株与四个孢子单核体标准菌株进行交配反应,初步确定出四种孢子单核体的交配型分别为: B17 (A2B2)、B177(A1B1)、B101(A2B1)和B65(A1B2)。  相似文献   

13.
A complex discrimination procedure was used to test class formation with multi-component figures in college students. First, selections of a red-+45 degrees -oriented rectangle (A1B1) instead of a red -45 degrees -oriented rectangle (A1B2) and of a green -45 degrees -oriented rectangle (A2B2) instead of a green-+45 degrees -oriented rectangle (A2B1), were reinforced. Second, selections of a +45 degrees -obtuse-angle-white hexagon (B1C1), instead of a +45 degrees -two-acute-angle hexagon (B1C2) and of a -45 degrees -two-acute-angle hexagon (B2C2), instead of a -45 degrees -obtuse-angle hexagon (B2C1), were reinforced. Subsequent tests with figures A1B1 and A2B1, A2B2 and A1B2, B1C1 and B2C1, and B2C2 and B1C2 demonstrated selection of the same figures as in training. Other tests with a novel figure compounded by color A1 and form C1 and a novel figure compounded by color A1 and form C2, or a novel figure compounded by A2 and C1 and a novel figure compounded by A2 and C2 demonstrated consistent selection of figures A1C1 and A2C2. A final test with figures A1C1 and A2C1, or with figures A2C2 and A1C2 also showed consistent selections of the same figures -A1C1 and A2C2. The resulting classification among selected and non-selected figures cannot be based on particular properties of the selected figures, or in a combination of a particular set of those properties, because both selected and non-selected figures were compounded by identical values. Instead, the participants selected the figures with two values of the same set (A1,B1, or C1, or A2,B2 or C2). Thus, these results demonstrated categorization based on the relations among the values of the figures. Therefore, these results have important implications for the study of concept formation.  相似文献   

14.
A problem frequently encountered when modeling the power frequency magnetic fields, B and A, produced by two sources is the necessity of estimating the root mean square (rms) magnitude of their sum, i.e., T = /B + A/, when the rms magnitudes, B and A, of the fields are specified by the model, but not necessarily their spatial directions, polarizations, and/or relative phase. The estimator Q = sqrt [B2+A2] was proposed many years ago for this purpose. The accuracy of this estimator is characterized in this paper. If it is known that B and A are approximately linearly polarized and in phase, the maximum bias (i.e., systematic) and random errors for Q used to estimate T are 6.1 and 35%, respectively, when B = A. These errors decrease as the difference between B and A increases. The bias and random errors are, respectively, 3.2 and 26% when B = 2A or A/2 and 0.2 and 5.8% when B = 10A or A/10. If the directions, relative phase, and polarizations of the two fields are unknown, Q has maximum bias and random errors of approximately 2.6 and approximately 23%, respectively, when B = A. These errors decrease to approximately 1.5 and approximately 18% when B =2 A or A/2 and approximately 0.08 and approximately 4.0% when B = 10A or A/10. If B and A are known to be linearly polarized and collinear, but with unknown phase between them, the maximum bias and random errors are 11 and 48%, respectively, when B = A. The errors are 5.1 and 32% when B = 2A or A/2 and 0.2 and 7.0% when B = 10A or A/10. Estimators for T with zero bias can be derived, but they are more complicated and increase overall accuracy very little.  相似文献   

15.
Protein phosphatase 2A (PP2A) is an abundant heterotrimeric serine/threonine phosphatase containing highly conserved structural (A) and catalytic (C) subunits. Its diverse functions in the cell are determined by its association with a highly variable regulatory and targeting B subunit. At least three distinct gene families encoding B subunits are known: B/B55/CDC55, B'/B56/RTS1 and B"/PR72/130. No homology has been identified among the B families, and little is known about how these B subunits interact with the PP2A A and C subunits. In vitro expression of a series of B56alpha fragments identified two distinct domains that bound independently to the A subunit. Sequence alignment of these A subunit binding domains (ASBD) identified conserved residues in B/B55 and PR72 family members. The alignment successfully predicted domains in B55 and PR72 subunits that similarly bound to the PP2A A subunit. These results suggest that these B subunits share a common core structure and mode of interaction with the PP2A holoenzyme.  相似文献   

16.
Overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, especially of B1 has been reported as a useful marker to detect cancers in early stage, although the biological reason is not clear. A2/B1 proteins were previously reported to bind telomeric DNA repeats. Alternative splicing of A2/B1 gene produces abundant A2, less abundant B1, and testis-specific minor isoforms B0a and B0b. In this study, B1 and B0b that have the N-terminal 12 amino acid insertion were suggested to have higher affinities to telomeric single-stranded DNA (ssDNA) than A2 and B0a. Kinetic analyses using purified B1 and B0b indicated that they interact dynamically with a single array of telomeric repeats. Furthermore, functional assays demonstrated that B1 and B0b bind with telomeric repeats in a tandem fashion and protect them from a nuclease and promote telomerase activity. A2/B1 proteins, especially B1 and B0b, may function as telomeric ssDNA-binding proteins in cancer and reproductive cells.  相似文献   

17.
In solution, S100B protein is a noncovalent homodimer composed of two subunits associated in an antiparallel manner. Upon calcium binding, the conformation of S100B changes dramatically, leading to the exposure of hydrophobic residues at the surface of S100B. The residues in the C-terminal domain of S100B encompassing Phe(87) and Phe(88) have been implicated in interaction with target proteins. In this study, we used two-hybrid technology to identify specific S100B target proteins. Using S100B as bait, we identify S100A6 and S100A11 as specific targets for S100B. S100A1, the closest homologue of S100B, is capable of interaction with S100B but does not interact with S100A6 or S100A11. S100B, S100A6, and S100A11 isoforms are co-regulated and co-localized in astrocytoma U373 cells. Furthermore, co-immunoprecipitation experiments demonstrated that Ca(2+)/Zn(2+) stabilizes S100B-S100A6 and S100B-S100A11 heterocomplexes. Deletion of the C-terminal domain or mutation of Phe(87) and Phe(88) residues has no effect on S100B homodimerization and heterodimerization with S100A1 but drastically decreases interaction between S100B and S100A6 or S100A11. Our data suggest that the interaction between S100B and S100A6 or S100A11 should not be viewed as a typical S100 heterodimerization but rather as a model of interaction between S100B and target proteins.  相似文献   

18.
B Falgout  M Pethel  Y M Zhang    C J Lai 《Journal of virology》1991,65(5):2467-2475
The cleavages at the junctions of the flavivirus nonstructural (NS) proteins NS2A/NS2B, NS2B/NS3, NS3/NS4A, and NS4B/NS5 share an amino acid sequence motif and are presumably catalyzed by a virus-encoded protease. We constructed recombinant vaccinia viruses expressing various portions of the NS region of the dengue virus type 4 polyprotein. By analyzing immune precipitates of 35S-labeled lysates of recombinant virus-infected cells, we could monitor the NS2A/NS2B, NS2B/NS3, and NS3/NS4A cleavages. A polyprotein composed of NS2A, NS2B, and the N-terminal 184 amino acids of NS3 was cleaved at the NS2A/NS2B and NS2B/NS3 junctions, whereas a similar polyprotein containing only the first 77 amino acids of NS3 was not cleaved. This finding is consistent with the proposal that the N-terminal 180 amino acids of NS3 constitute a protease domain. Polyproteins containing NS2A and NS3 with large in-frame deletions of NS2B were not cleaved at the NS2A/NS2B or NS2B/NS3 junctions. Coinfection with a recombinant expressing NS2B complemented these NS2B deletions for NS2B/NS3 cleavage and probably also for NS2A/NS2B cleavage. Thus, NS2B is also required for the NS2A/NS2B and NS2B/NS3 cleavages and can act in trans. Other experiments showed that NS2B was needed, apparently in cis, for NS3/NS4A cleavage and for a series of internal cleavages in NS3. Indirect evidence that NS3 can also act in trans was obtained. Models are discussed for a two-component protease activity requiring both NS2B and NS3.  相似文献   

19.
Search of possible immunogenetic markers of tendency to form aneuploid offspring was carried out. We have studied HLA-antigens distribution among families with Down syndrome and Turner syndrome children and among families with miscarriages. The disposition to reproduction of affected offspring is associated with following HLA-antigens: B40, B41 and B51. The most typical haplotypes among families with affected offspring were: A2B27, A2B40, A2B51, A9B51, A10B8, A10B40. The HLA-antigens distribution among families with miscarriages supports evidence, that certain haplotypes can contribute to aneuploidy in progeny.  相似文献   

20.
Eight patients (4 suffering from acute myeloid leukemia) exhibiting a loss of ABO red cell antigens, as seen by a mixed-field reaction pattern in agglutination tests, were selected and examined for the level of the A, -B, -H blood group glycosyltransferases within membranes prepared from erythrocyte subpopulations (A or B positive and A or B negative red cells). A or B enzyme activities were largely decreased in membranes which had lost A or B antigens (A or B negative subpopulations) but were within normal level in membrane from cells which had not lost A or B antigens (A or B positive subpopulations). The H enzyme level which was frequently low in the serum was within normal limits in the membrane preparations examined. Since A or B negative subpopulations were normally glycosylated in vitro into A or B reactive structures, the results demonstrate that loss of A or B antigens is related to some alteration of the blood group gene products rather than to significant abnormalities of the membrane precursors.  相似文献   

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