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161.
162.
A subcommittee of The Social Issues Committee of The American Society of Human Genetics (ASHG), aware of the growing interest in the implications of inheritance and adoption, in 1987 began surveying the 50 states' and Washington DC's public adoption agencies regarding this issue, and it completed the survey in 1988. In 1987, two surveys obtained data on each state's legal requirements for obtaining genetic information and on what each public adoption agency collected as genetic history. These results were presented in a poster at the 1987 ASHG annual meeting in San Diego. In 1988, a questionnaire was sent to the same agencies to elicit opinions as to whether adoption agencies should systematically collect genetic information to share with the adoptive family and adoptee, whether legislation should be mandated to collect such information, and whether genetic education programs should be developed and implemented for adoption-agency staff. On the basis of responses to the 1988 questionnaire, it was concluded that there is an interest in developing a uniform set of genetic information which should be part of a child's adoption record and that there is a need for genetic education programs for adoption workers. Responses to the desirability of mandating legislation for this purpose were less consistent.  相似文献   
163.
A semi-empirical model of methane emission from flooded rice paddy soils   总被引:13,自引:0,他引:13  
Reliable regional or global estimates of methane emissions from flooded rice paddy soils depend on an examination of methodologies by which the current high variability in the estimates might be reduced. One potential way to do this is the development of predictive models. With an understanding of the processes of methane production, oxidation and emission, a semi-empirical model, focused on the contributions of rice plants to the processes and also the influence of environmental factors, was developed to predict methane emission from flooded rice fields. A simplified version of the model was also derived to predict methane emission in a more practical manner. In this study, it was hypothesized that methanogenic substrates are primarily derived from rice plants and added organic matter. Rates of methane production in flooded rice soils are determined by the availability of methanogenic substrates and the influence of environmental factors. Rice growth and development control the fraction of methane emitted. The amount of methane transported from the soil to the atmosphere is determined by the rates of production and the emitted fraction. Model validation against observations from single rice growing seasons in Texas, USA demonstrated that the seasonal variation of methane emission is regulated by rice growth and development. A further validation of the model against measurements from irrigated rice paddy soils in various regions of the world, including Italy, China, Indonesia, Philippines and the United States, suggests that methane emission can be predicted from rice net productivity, cultivar character, soil texture and temperature, and organic matter amendments.  相似文献   
164.
Neurodevelopmental disorders are characterized by deficits in communication, cognition, attention, social behavior and/or motor control. Previous studies have pointed to the involvement of genes that regulate synaptic structure and function in the pathogenesis of these disorders. One such gene, GRM7, encodes the metabotropic glutamate receptor 7 (mGlu7), a G protein‐coupled receptor that regulates presynaptic neurotransmitter release. Mutations and polymorphisms in GRM7 have been associated with neurodevelopmental disorders in clinical populations; however, limited preclinical studies have evaluated mGlu7 in the context of this specific disease class. Here, we show that the absence of mGlu7 in mice is sufficient to alter phenotypes within the domains of social behavior, associative learning, motor function, epilepsy and sleep. Moreover, Grm7 knockout mice exhibit an attenuated response to amphetamine. These findings provide rationale for further investigation of mGlu7 as a potential therapeutic target for neurodevelopmental disorders such as idiopathic autism, attention deficit hyperactivity disorder and Rett syndrome.  相似文献   
165.
166.
1. The impact of environmental disturbance and habitat loss on associated species is expected to be dependent on a species' level of specialization. We examined habitat use and specialization of coral reef fish from the diverse and ecologically important family Pomacentridae, and determined which species are susceptible to declines in coral cover due to disturbance induced by crown-of-thorns seastar (COTS, Acanthaster planci L.). 2. A high proportion of pomacentrid species live in association with live coral as adults (40%) or juveniles (53%). Adults of many species had strong affiliations with branching corals, while juveniles favoured plating growth forms, reflecting the sizes of refuge provided by coral types. 3. Juveniles of species that associated with coral had narrower niche breadths than adult conspecifics, due to associations with specific coral types. The especially high coral association and narrower niche breadth of juveniles suggest that the presence of live coral is crucial for many species during early life history, and that disturbance-induced coral loss may have serious flow-on effects on adult abundance. 4. Microhabitat availability was a poor predictor of fish species abundance. Significant correlations between coverage of coral types and abundance of five adults and two juvenile species were detected; however, these relationships explained <35% and <10% of the variation in abundance of adult and juvenile species, respectively. 5. Niche breadth explained 74% of the variation in species' mean response to coral decline and it is clear that disturbance has a greater impact on resource specialists, suggesting that increasing frequency and intensity of coral loss will cause reef fish communities to become dominated by habitat generalists at the expense of coral-dwelling specialists.  相似文献   
167.
Between September 1990 and November 1991, 19 Sphenomorphus spp. skinks, including nine S. jobiense, three S. simus, and seven Solomon ground skinks, S. solomonis (Boulenger), were collected from Madang and Morobe Provinces, Papua New Guinea (PNG), and examined for coccidia. A single S. solomonis was found to be infected with a new species of Eimeria Schneider, 1875. Oöcysts of Eimeria perkinsae n. sp. are ellipsoidal with a smooth, colourless, bi-layered wall, measure 18.6 × 14.7 μm, and have a length/width (L/W) ratio of 1.3; both micropyle and oöcyst residuum are absent, but a fragmented polar granule is present. Sporocysts are ovoidal, 8.9 × 6.4 μm, L/W 1.4; neither Stieda, sub-Stieda or para-Stieda bodies are present; a sporocyst residuum consisted of a loose cluster of granules dispersed between sporozoites. Sporozoites are comma-shaped with spheroidal anterior and posterior refractile bodies. This represents the first report of coccidia from this skink genus.  相似文献   
168.
A series of heterocyclic 2-(3,5-dimethylphenyl)tryptamine derivatives was prepared and evaluated on a rat gonadotropin releasing hormone receptor assay. The carbon tether length and heterocyclic ring attached to the amino group of 2-(3,5-dimethylphenyl)tryptamine were varied. Several of these derivatives were potent GnRH antagonists with the most potent compound having an IC50 of 16 nM.  相似文献   
169.
The sulfur amino acids, methionine and cysteine play crucial roles in cells as a substrate for protein synthesis, as a methyl donor, and for the synthesis of sulfur-containing compounds, including the key intracellular tripeptide, glutathione. Homocysteine is an intermediary metabolite formed during the metabolism of methionine to cysteine. Dysregulation of homocysteine metabolism is implicated in adverse clinical outcomes such as increased risk of cardiovascular disease, stroke, Alzheimer's disease dementia and osteoporosis. While hyperhomocysteinemia is commonly observed in those conditions, the impact on other related metabolites is condition-specific. Therefore, there exists a need to establish precise and sensitive analytical techniques that allow for the simultaneous measurement of homocysteine and related metabolites in biological samples. The current review outlines the development and use of liquid chromatography electrospray tandem mass spectrometry (LC–MS/MS) to simultaneously measure metabolites involved in sulfur amino acid metabolism. Additionally, extensions of the technique in relation to the measurement of sulfur amino acid and one-carbon kinetics in vivo are discussed. The LC–MS/MS technique has the capacity for unambiguous analyte identification and confirmation, due to its high specificity and sensitivity. It has the greatest potential of being accepted and utilized as a dedicated homocysteine and its related metabolite Standard reference method (SRM).  相似文献   
170.
In the absence of a peptidylproline substrate, the oxidative decarboxylation of 2-oxoglutarate by prolyl 4-hydroxylase (prolyl-glycyl-peptide,2-oxoglutarate:oxygen oxidoreductase (4-hydroxylating), EC 1.14.11.2) is stoicheiometrically coupled to the oxidation of ascorbate. The Km and Kd for O2 in this partial reaction are 1.5 mM, this value being one order of magnitude higher than the Km and Kd for O2 in the complete reaction in the presence of (Pro-Pro-Gly)5, indicating that in this case O2 can become enzyme-bound predominantly after the interaction of the peptide substrate with the enzyme. The Km values for 2-oxoglutarate in the partial and the complete reactions are the same. In the absence of both a peptide substrate and ascorbate 2 mol CO2 per mol enzyme are produced in the first 1-1.5 min, during which the enzyme becomes inactivated and, as shown earlier (De Jong , L., Albracht , S.P.J. and Kemp, A. (1982) Biochim. Biophys. Acta 704, 326-332) enzyme-bound Fe2+ becomes oxidized to Fe3+. The results are consistent with a mechanism in which a Fe2+O complex is the O-transferring intermediate involved in peptidylproline hydroxylation.  相似文献   
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