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1.
A survey of adult male immates of the major institutions for mental patients in Belgium was undertaken in 1965. Out of 10417 males examined 61 had positive sex chromatin (5.8%); 201 had bilateral small testis (1.9%), 4 hypogonad patients carried a D/D translocation. Out of 857 karyotyped children, 2.9% carried an autosomal or sex-chromosomal anomaly other than trisomy G. This prevalence of chromosomal anomalies in children with low I.Q. (less than 50) emphasizes the need for further studies.  相似文献   

2.
Indians or South Asians have been found to be particularly susceptible to coronary heart disease (CHD) in many countries. A novel risk factor for CHD may be coenzyme Q10 (CoQ10). In this study, plasma CoQ10 (including ubiquinol-10, CoQ10H2, and total CoQ10), various lipid parameters, and antioxidant levels were determined in a random sample of Indians and Chinese from the general population of Singapore. The reduced form of coenzyme Q10, CoQ10H2, and total Q10 concentrations in plasma were significantly lower in Indian males than Chinese males. Although no significant differences were found in plasma concentrations of total cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL) between the two ethnic groups, the ratios of ubiquinol and total CoQ10 to triglycerides, total cholesterol, and LDL were significantly lower in Indian males than Chinese males. There were no significant ethnic differences in other antioxidant levels, including trans-retinol, alpha-tocopherol, and ascorbic acid. The consistently lower values of coenzyme Q10, especially its reduced form, in Indian males may contribute to the higher susceptibility of this ethnic group to coronary heart disease.  相似文献   

3.
Fourteen families with X-linked mental retardation (XMR) have been studied clinically and cytogenetically. All affected males failed to show a fragile site (FS) on Xq of their peripheral lymphocytes. Five families may be considered examples of Renpenning syndrome while the remaining may be divided in two groups: one of seven (type I) and one of two (type II). The seven families of type I had some physical features of the Martin-Bell syndrome but with normal to large sized testes whence the name of X-linked MR with slight macroorchidism (XMR +/- MO). The two families of type II showed unremarkable facial appearance, mild to moderate degree of MR and a certain microorchidism whence the possible name of X-linked MR with different degree of microorchidism (XMR +/- MiO).  相似文献   

4.
通过比较抱对和非抱对普通东方小蛙(Crinia signifera) 的吻尾干骨长(体长) 和检测个体较大或状态较好的雄体是否为成功繁殖个体, 检测雌蛙体长与交配成功的雄蛙的体长和相对状态(体重/体长) 之间是否存在线形关系, 评估交配与个体大小之间的关系。在实验室内, 令未交配雌体选择随机选出的雄体, 观测雌体是否与最大的雄体交配; 将抱对的蛙暴露于其它雄蛙, 观测其它较大或较小的雄蛙是否取代已抱对的雄蛙。结果表明: 抱对雄蛙和雌蛙的个体大小无显著的关系, 成功交配的雄蛙并不比未交配的雄蛙大, 其它雄蛙不能取代已抱对的雄蛙。在这一C. signifera种群中, 繁殖盛期雄性个体的大小似乎不影响交配成功率, 在此期间即便存在配偶选择, 亦决定于与雄性个体大小无关的其它因素。在更长的繁殖期内, 雄性个体大小则与交配成功率有关, 这是该种的典型特征。  相似文献   

5.
Alternative reproductive tactics are often correlated with phenotype, density, environment, or social context. Male horseshoe crabs(Limulus polyphemus) have two mating tactics that are associatedwith phenotype. Males in good condition arrive at the nestingbeach and spawn while attached to females, whereas those inpoorer condition come ashore unattached and crowd around thenesting couples as satellites, fertilizing eggs through sperm competition. The correlation between mating tactic and phenotypemay be due to males choosing tactics based on condition, orit may be that males that have not found a female choose tocome ashore as satellites. To distinguish between these twopossibilities, I conducted an experiment on male horseshoe crabsin the field at Seahorse Key on the northern Gulf coast ofFlorida. I prevented males from attaching to females by placingsmall plastic bags over the claws they use to attach. The resultsshowed that males in poor condition came ashore as satellites,whereas males in good condition remained at sea. This meansthat mating tactics are cued by information about the male'scondition and not about whether he found a female. The evolutionof phenotype-correlated mating tactics can be represented bya model in which the fitness of each tactic changes with conditionand fitness curves cross. I hypothesize that male horseshoecrabs in good condition have higher fitness when attached and that males in poorer condition to better when unattached.  相似文献   

6.
The I-conotoxin superfamily (I-Ctx) is known to have four disulfide bonds with the cysteine arrangement C-C-CC-CC-C-C, and the members inhibit or modify ion channels of nerve cells. Recently, Olivera and co-workers (FEBS J. 2005; 272: 4178-4188) have suggested that the previously described I-Ctx should now be divided into two different gene superfamilies, namely, I1 and I2, in view of their having two different types of signal peptides and exhibiting distinct functions. We have revisited the 28 entries presently grouped as I-Ctx in UniProt Swiss-Prot knowledgebase, and on the basis of in silico analysis have divided them into I1 and I2 superfamilies. The sequence analysis has provided a framework for in silico annotation enabling us to carry out computer-based functional characterization of the UniProtKB/TrEMBL entry Q59AA4 from Conus miles and to predict it as a member of the I2 superfamily. Furthermore, we have predicted the mature toxin of this entry and have proposed that it may be an inhibitor of voltage-gated potassium channels.  相似文献   

7.
Six patients (4 females and 2 males) with terminal deletion of the short arm of chromosome 9 distal to band p22 are described. The disorder constitutes a clinically identifiable syndrome consisting of mental retardation, sociable personality, trigonocephaly, mongoloid eyes, wide flat nasal bridge, anteverted nostrils, long upper lip, short neck, long digits mostly secondary to long middle phalanges, and predominance of whorls on fingers. The findings suggest that the clinical features are antithetical to the trisomy 9p syndrome. The deleted chromosome segment is relatively small and could be easily overlooked. It is hoped that this delineation of clinical features seen in 9,p- patients may help in focusing attention on the small deletion.  相似文献   

8.
Laccases are industrially attractive enzymes and their applications have expanded to the field of bioremediation. The challenge of today's biotechnology in enzymatic studies is to design enzymes that not only have a higher activity but are also more stable and could fit well with the condition requirements. Laccases are known to oxidize non-natural substrates like polycyclic aromatic hydrocarbons (PAHs). We suppose by increasing the hydrophobicity of laccase, it would increase the chance of the enzyme to meet the hydrophobic substrates in a contamination site, therefore increasing the bioremediation efficacy of PAHs from environment. In this attempt, the applications of evolutionary trace (ET), molecular surface accessibility and hydrophobicity analysis on laccase sequences and laccase's crystal structure (1KYA) are described for optimal design of an enzyme with higher hydrophobicity. Our analysis revealed that Q23A, Q45I, N141A, Q237V, N262L, N301V, N331A, Q360L and Q482A could be promising exchanges to be tested in mutagenesis experiments.  相似文献   

9.
The plastocyanin binding domain of photosystem I.   总被引:2,自引:0,他引:2       下载免费PDF全文
The molecular recognition between plastocyanin and photosystem I was studied. Photosystem I and plastocyanin can be cross-linked to an active electron transfer complex. Immunoblots and mass spectrometric analysis of proteolytic peptides indicate that the two negative patches conserved in plant plastocyanins are cross-linked with lysine residues of a domain near the N-terminus of the PsaF subunit of photosystem I. Conversion of these negative to uncharged patches of plastocyanin by site-directed mutation D42N/E43Q/D44N/E45Q and E59Q/E60Q/D61N respectively, reveals the first patch to be essential for the electrostatic interaction in the electron transfer complex with photosystem I and the second one to lower the redox potential. The domain in PsaF, not found in cyanobacteria, is predicted to fold into two amphipathic alpha-helices. The interacting N-terminal helix lines up six lysines on one side which may guide a fast one-dimensional diffusion of plastocyanin and provide the electrostatic attraction at the attachment site, in addition to the hydrophobic interaction in the area where the electron is transferred to P700 in the reaction center of photosystem I. This two-step interaction is likely to increase the electron transfer rate by more than two orders of magnitude in plants as compared with cyanobacteria. Our data resolve the controversy about the function of PsaF.  相似文献   

10.
Allan-Herndon syndrome. I. Clinical studies.   总被引:5,自引:4,他引:1       下载免费PDF全文
A large family with X-linked mental retardation, originally reported in 1944 by Allan, Herndon, and Dudley, has been reinvestigated. Twenty-nine males have been affected in seven generations. Clinical features include severe mental retardation, dysarthria, ataxia, athetoid movements, muscle hypoplasia, and spastic paraplegia with hyperreflexia, clonus, and Babinski reflexes. The facies appear elongated with normal head circumference, bitemporal narrowing, and large, simple ears. Contractures develop at both small and large joint. Statural growth is normal and macroorchidism does not occur. Longevity is not impaired. High-resolution chromosomes, serum creatine kinase, and amino acids are normal. This condition, termed the Allan-Herndon syndrome, appears distinct from other X-linked disorders having mental retardation, muscle hypoplasia, and spastic paraplegia.  相似文献   

11.
A family is described in which three normal females transmitted to seven males X-linked mental retardation associated with macro-orchidism and a fragile site on the long arm of the X chromosome -- fra(X)(q27). The affected males also had minor clinical features in common: a large forehead, long face, large ears, a long upper lip and large extremities.  相似文献   

12.
Sexual and parental conflicts can arise because males benefit by inducing elevated reproductive effort in their mates. For females, the costs of such manipulation are often manifested later in life, and may therefore covary with female life expectancy. Here, I outline a simple female life‐history model where female life expectancy reflects extrinsic mortality rate, and elevated reproductive effort causes accelerated senescence. Using this model, I show that variation in extrinsic mortality rate can modulate the magnitude and sign of fitness effects that male manipulation has on females. This result has several interesting implications. First, it suggests that the fitness effects of sexual interactions can depend on ecological factors, such as predation, that influence life expectancy. Second, if mortality risk is condition‐dependent but reproductive effort is not fully optimized in relation to individual condition, then sexual conflict intensity may increase with individual condition, selecting for condition‐dependent reproductive strategies. Third, if males vary in manipulativeness, then the fitness effects of mating with a given male phenotype may depend on both female condition and extrinsic mortality rate. Fourth, life span extension in the laboratory can lead to overestimation of sexual and parental conflicts. Life expectancy may therefore be a key factor in sexual coevolution.  相似文献   

13.
During an ongoing study on X-linked mental retardation, we ascertained a large family in which mild mental retardation was cosegregating with a fragile site at Xq27-28. Clinical, psychometric, cytogenetic, and molecular studies were performed. Apart from mild mental retardation, affected males and females did not show a specific clinical phenotype. Psychometric assessment of four representative affected individuals revealed low academic achievements, with verbal and performance IQs of 61-75 and 70-82, respectively. Cytogenetically the fragile site was always present in affected males and was not always present in affected females. With FISH the fragile site was located within the FRAXE region. The expanded GCC repeat of FRAXE was seen in affected males and females either as a discrete band or as a broad smear. No expansion was seen in unaffected males, whereas three unaffected females did have an enlarged GCC repeat. Maternal transmission of FRAXE may lead to expansion or contraction of the GCC repeat length, whereas in all cases of paternal transmission contraction was seen. In striking contrast to the situation in fragile X syndrome, affected males may have affected daughters. In addition, there appears to be no premutation of the FRAXE GCC repeat, since in the family studied here all males lacking the normal allele were found to be affected.  相似文献   

14.
Q10 is a class I molecule previously proven to be secreted rather than membrane bound. To measure the amount of Q10 in various mouse sera, a quantitative Western blot assay was developed. Q10 was the only class I molecule detectable in mouse sera. It occurs as a high m.w. complex of 200,000 to 300,000. The amount of Q10 in serum varies among different mouse strains and is controlled by a region telomeric to H-2S. Mice of the f haplotype do not express Q10, but all other mice examined (20 strains) with inbred or wild-derived H-2 haplotypes do. The H-2 haplotypes rank according to their levels of Q10 as follows: z, s greater than k, b greater than d, q greater than f; and the actual values range from to 60 micrograms/ml to undetectable levels in serum. In some strains the levels are higher in males than in females. The levels increase with age and decrease during pregnancy but not during lactation. There is a dramatic decrease after the injection of irritants or syngeneic tumor transplantation, but allostimulation has no effect on Q10 levels. The possible significance of this soluble class I molecule is discussed in the light of our findings.  相似文献   

15.
The effect of thylakoid phosphorylation on noncyclic electron transport in spinach chloroplasts was investigated by measuring both the reduction of nicotinamide adenine dinucleotide phosphate (NADP) and the steady-state redox level of the primary electron acceptor quinone of photosystem II (Q) during electron flow to NADP. These data are compared with the theoretical predictions for an electron transport model which relates both the redox levels of Q and the photosystem II optical cross section to the overall velocity of noncyclic electron flow. It is demonstrated that transfer of 15-20% of the photosystem II antenna to photosystem I may stimulate electron flow to NADP only if Q is less than 60-70% oxidized (this condition exists with our thylakoids, even at extremely low absorption fluxes, when the illumination is not specifically enriched in photosystem I absorbed wavelengths); in phosphorylated thylakoids the steady-state redox level Q is substantially shifted to a more oxidized one (measurements of this parameter using light of different wavelengths quantitatively support the idea that thylakoid phosphorylation leads to increased photosystem I and decreased photosystem II cross sections); thylakoid phosphorylation leads to stimulated noncyclic electron flow to NADP only when the increased photosystem I antenna is able to bring about large increases in the steady-state level of oxidized Q.  相似文献   

16.
In 1954, Papillon-Léage and Psaume described a dominant, X-linked condition which they named oro-facio-digital (OFD). This condition was split into at least nine syndromes, the more common being OFD I. We report a girl with OFD I syndrome followed up for 23 years. Clinical examination showed cleft palate, median cleft lip, multiple oral frenulae, lobulated tongue and brachydactyly. There was no mental retardation. At 19 years of age, renal insufficiency appeared. A renal transplantation was performed. The parents were unaffected. An older brother had hydrocephaly, bilateral optic atrophy and mental retardation. A younger sister is unaffected. A mutation, an insertion of a G leading to a frameshift in the OFD 1 gene, was identified in this patient.  相似文献   

17.
After the deployment of several whale carcasses in Monterey Bay, California, a time-series analysis revealed the presence of a new species of Osedax, a genus of bone-eating siboglinid annelids. That species is described here as Osedax roseus n. sp. It is the fifth species described since the erection of this genus and, like its congeners, uses a ramifying network of "roots" to house symbiotic bacteria. In less than 2 months, Osedax roseus n. sp. colonized the exposed bones of a whale carcass deposited at 1018-m depth, and many of the females were fecund in about 3 months post-deployment. As with other Osedax spp., the females have dwarf males in their tube lumens. The males accrue over time until the sex ratio is markedly male-biased. This pattern of initial female settlement followed by gradual male accumulation is consistent with the hypothesis that male sex may be environmentally determined in Osedax. Of the previously described species in this genus, Osedax roseus n. sp. is most similar to O. rubiplumus, but it has several anatomical differences, as well as much smaller females, dwarf males, and eggs. Osedax roseus n. sp. is markedly divergent (minimally 16.6%) for mitochondrial cytochrome oxidase subunit I (mtCOI) sequences from any other Osedax species.  相似文献   

18.
The temperature-sensitive conjugational transfer-deficient mutant Escherichia coli JCFL39, carrying a traD(Ts) mutation, is herein described as also being temperature sensitive for group I RNA phages (MS2, f2, and R17) but not for Q beta. Temperature shift experiments showed that the growth of group I phage MS2 in the mutant could be inhibited by a post-penetration event at high temperature. A possible role for the traD cistron of sex factor F in the intracellular development of MS2 is suggested.  相似文献   

19.
Impatiens shimianensis Q. Luo (Balsaminaceae), a new species from Shimian county in southwestern Sichuan province, China, is reported and its morphological characteristics are described and illustrated. Pollen grain morphology and seeds under SEM are also described. The new species is somewhat similar to I. bahanensis, I. brachycentra, I. laxiflora, I. parviflora and I. racemosa, but differs mainly by having leaf blades with white short stiff adpressed hairs; basal lobes of lateral united petals triangular, distal lobes lanceolate; and lower sepal salver‐shaped. The distinguishing characters for these six Impatiens species are given in a table.  相似文献   

20.
Sexual motivation and sexual arousal are widely used concepts. While there seem to be considerable agreement as to the meaning of sexual motivation, there is certain confusion about the exact meaning of sexual arousal. Some use it as a synonym to sexual motivation and others make it equivalent to erection or vaginal lubrication. An unresolved question is the relationship between sexual arousal and general arousal as well as that between arousal and motivation. I present arguments for the view that arousal refers to the general state of alertness of the organism. Consequently, there is no such thing as a specific sexual arousal. I suggest that this term should be abandoned, or if that is not feasible, to make it a synonym to enhanced genital blood flow. The notion of a subjective sexual arousal, some kind of vaguely described mental state, seems to lack all explanatory value. I then show that general arousal is an important determinant of sexual motivation, and that the execution of copulatory acts leads to increased general arousal. This increase leads to enhanced sexual motivation, making the activation of sexual reflexes requiring high levels of motivation possible. Examples of such reflexes may be ejaculation in males of many species, and perhaps the psychic state of orgasm in women.  相似文献   

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