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1.
Peak bone density is an important determining factor of future osteoporosis risk. We previously identified a quantitative trait locus (QTL) that contributes significantly to high bone density on mouse chromosome 1 from a cross between C57BL/6J (B6) and CAST/EiJ (CAST) mouse strains. We then generated a congenic strain, B6.CAST-1T, in which the chromosomal fragment containing this QTL had been transferred from CAST to the B6 background. The congenic mice have a significantly higher bone density than the B6 mice. In this study we performed cDNA microarray analysis to evaluate the gene expression profile that might yield insights into the mechanisms controlling the high bone density by this QTL. This study led to several interesting observations. First, approximately 60% of 8,734 gene accessions on GEM I chips were expressed in the femur of B6 mice. The expression and function of two-thirds of these expressed genes and ESTs have not been documented previously. Second, expression levels of genes related to bone formation were lower in congenic than in B6 mice. These data are consistent with a low bone formation in the congenic mice, a possibility that is confirmed by reduced skeletal alkaline phosphatase activity in serum compared with B6 mice. Third, expression levels of genes that might have negative regulatory action on bone resorption were higher in congenic than in B6 mice. Together these findings suggest that the congenic mice might have a lower bone turnover rate than B6 mice and raise the possibility that the high bone density in the congenic mice could be due to reduced bone resorption rather than increased bone formation. Electronic Publication  相似文献   

2.
The EGTA iontophoresis influence on activity of 63 neurons of the rat's sensomotor cortex has been investigated. Neurons with high and low sensitivity to calcium ions decreasing level in extracellular medium have been found. A possibility of partial reversible functional isolation of neuron from neuronal net by blocking the transmitter release by EGTA has been shown.  相似文献   

3.
Willow is shown to be able to accumulate high levels of heavy metal ions such as cadmium and zinc. The properties of willow to be used in phytoextraction therefore have been studied. In this article, results from different studies on heavy metals and willow have been used to demonstrate the capacity and possibility of using Salix in phytoextraction.  相似文献   

4.
Currently, single cell oils (SCO) attract much attention because of their bi-function as a supplier of functional oils and feedstock for biodiesel production. However, high fermentation costs prevent their further application, and the possibility and potential of their industrialization is suspected. Therefore, various low-cost, hydrophilic and hydrophobic substrates were utilized for SCO production. Of these substrates, lignocellulosic biomass, which is the most available and renewable source in nature, might be an ideal raw material for SCO production. Although many reviews on SCO have been published, few have focused on SCO production from low-cost substrates or evaluated the possibility and potential of its industrialization. Therefore, this review mainly presents information on SCO and its production using low-cost substrates and mostly focuses on lignocellulosic biomass. Finally, the possibility and potential of SCO industrialization is evaluated.  相似文献   

5.
The average protein (E+K)/(Q+H) ratio in organisms has already been demonstrated to have a strong correlation with their optimal growth temperature. Employing the Thermo-Search web tool, we used this ratio as a basis to look for thermostable proteins in a mesophile, Xylella fastidiosa. Nine proteins were chosen to have their three-dimensional structures modeled by homology, using mainly proteins from mesophiles as templates. Resulting models featured a high number of hydrophobic interactions, a property that has been previously associated with thermostability. These results demonstrate the interesting possibility of using the (E+K)/(Q+H) ratio to find individual thermostable proteins in mesophilic organisms.  相似文献   

6.
We tested effects of praziquantel, an antischistosomal compound, on clinical and immunological parameters of chronic schistosomiasis japonica. Two Japanese patients, who had high antibody titers to Schistosoma japonicum antigens but no fecal schistosome eggs or no or mild symptoms complained, were treated with praziquantel. Within two years after treatment, anti-schistosome antibodies in sera from the patients became negative in enzyme-linked immunosorbent assay. There was no significant alteration in cellular immunity to the parasite. Although S. japonicum infection is believed to have been eradicated in Japan, our present results seem to suggest the possibility that a few Japanese individuals, who have high anti-schistosome antibody, still harbor live parasites.  相似文献   

7.
Morphological and molecular studies on a tardigrade species have been carried out to verify the possibility of using a DNA barcoding approach for species identification in this phylum. Macrobiotus macrocalix Bertolani & Rebecchi, 1993 was chosen as the test species since it belongs to a group of species in which the taxonomy is quite problematic. Animals and eggs belonging to three Italian and one Swedish populations have been investigated. Both morphological and molecular analyses show that all the populations belong to the same species. The low genetic distances recorded among the studied populations (0.3-1.0%) and the high genetic distance (15.9-16.3%) between these populations and a closely related species confirm the possibility of identifying a specimen of this species by its cytochrome oxidase subunit I sequence. Data from other authors support our results indicating that DNA barcoding can be applied to tardigrades. With our protocols, we have obtained voucher specimens that enable us to show a correspondence between morphology and molecular data.  相似文献   

8.
The possibility that proteins reaching the abdominal ganglion of Aplysia by axonal transport from the circumesophageal ganglia might be subject to secretion in that structure was examined. Transported labeled protein was found to be released from the abdominal ganglion; such release was enhanced by exposure to a high K+ medium and by electrical stimulation of the transporting axons. Stimulation of release was inhibited by lowering the Ca2+/Mg2+ ratio of the medium. The released material is predominantly of 1--2000 daltons in molecular weight and appears to have been derived from a group of transported peptides of about the same size. The possibility is raised that these data may reflect the existence of a peptidergic second-order neurosecretory pathway in this nervous system.  相似文献   

9.
An improved method is presented for preparing optically active cyanohydrins in high yield and high enantioselectivity, using R-oxynitrilase from almonds as the catalyst in a biphasic water-organic solvent system. Reaction conditions for two representative substates have been studied with respect to conversion, optical purity and enzyme stability.

The suitability of the procedure for industrial use was substantiated by the possibility of reusing the enzyme-containing aqueous phase for the synthesis of R-mandelonitrile.  相似文献   

10.
PeterT.  White  IainR. F.  Brown 《Journal of Zoology》1978,185(4):491-503
Various haematological parameters have been measured in a sample of wild African elephants from two game parks in Uganda. The results are compared with those of other authors for the African and Indian elephant and other mammals. No intersex differences were found to occur but calves (1–5 years) differed from the population as a whole in several respects. Some values varied with season and this may be attributed to the effect of dehydration during the dry season. A number of elephants from one of the parks had abnormally high red cell numbers and the possibility is considered that this may reflect an incidence of habitat induced cardiovascular disease.  相似文献   

11.
Underground storage organs (USOs) have been proposed as critical fallback foods for early hominins in savanna, but there has been little discussion as to which habitats would have been important sources of USOs. USOs consumed by hominins could have included both underwater and underground storage organs, i.e., from both aquatic and terrestrial habitats. Shallow aquatic habitats tend to offer high plant growth rates, high USO densities, and relatively continuous USO availability throughout the year. Baboons in the Okavango delta use aquatic USOs as a fallback food, and aquatic or semiaquatic USOs support high-density human populations in various parts of the world. As expected given fossilization requisites, the African early- to mid-Pleistocene shows an association of Homo and Paranthropus fossils with shallow-water and flooded habitats where high densities of plant-bearing USOs are likely to have occurred. Given that early hominins in the tropics lived in relatively dry habitats, while others occupied temperate latitudes, ripe, fleshy fruits of the type preferred by African apes would not normally have been available year round. We therefore suggest that water-associated USOs were likely to have been key fallback foods, and that dry-season access to aquatic habitats would have been an important predictor of hominin home range quality. This study differs from traditional savanna chimpanzee models of hominin origins by proposing that access to aquatic habitats was a necessary condition for adaptation to savanna habitats. It also raises the possibility that harvesting efficiency in shallow water promoted adaptations for habitual bipedality in early hominins. Am J Phys Anthropol 140:630–642, 2009. © 2009 Wiley-Liss, Inc.  相似文献   

12.
An improved method is presented for preparing optically active cyanohydrins in high yield and high enantioselectivity, using R-oxynitrilase from almonds as the catalyst in a biphasic water-organic solvent system. Reaction conditions for two representative substates have been studied with respect to conversion, optical purity and enzyme stability.

The suitability of the procedure for industrial use was substantiated by the possibility of reusing the enzyme-containing aqueous phase for the synthesis of R-mandelonitrile.  相似文献   

13.
Trans-4-hydroxy-N-methylproline and N-methylproline have been isolated from several Angiosperm species, but the striking feature is the high content of these two proline derivatives, being in excess of 1% of the dry weight of Berchemia zeyheri, Critoniella vargasiana, Hovenia dulcis and Serjania communis and in excess of 0.8% of Berberis aggregata and Annona chirimola. These high contents suggest the possibility that these compounds have a function in abiotic stress resistance of these species.  相似文献   

14.
Metabolites excreted into culture medium by human skin fibroblasts have been studied by high resolution gas chromatography and mass spectrometry. Parameters for 29 metabolites have been obtained and 11 of them have been identified. Excreted metabolites reflect activity of certain metabolic processes in fibroblasts. Comparison of chromatographic and mass spectrometric parameters of cellular metabolites with the metabolites excreted with urine revealed that most metabolites excreted from fibroblasts differ from urine metabolites. The possibility for secondary transformation of cell metabolites in organism and specificity of metabolism in different tissues has been discussed.  相似文献   

15.
A novel amperometric biosensor highly selective to L-lactate has been developed using L-lactate-cytochrome c oxidoreductase (flavocytochrome b2) isolated for the first time from thermotolerant methylotrophic yeast Hansenula polymorpha as biorecognition element. Different immobilization methods and low-molecular free-diffusing redox mediators have been tested for optimising the electrochemical communication between the immobilized enzyme and the electrode surface. Moreover, the possibility of direct electron transfer from the reduced form of FCb2 to carbon electrodes has been evaluated. The bioanalytical properties of FCb2-based biosensors, such as signal rise time, dynamic range, dependence of the sensor output on the pH value, the temperature and the storage stability were investigated, and the proposed biosensor demonstrated a very fast response and a high sensitivity and selectivity for L-lactate determination.  相似文献   

16.
The possibility of transition of saprotrophic and enteropathohenic bacterial populations following the chain of naturally related habitats—fodder-animal gastrointestinal tract (GIT)-animals excrement-soil-plants and again animals with a cyclic formation—has been investigated quantitatively. All bacteria used in the experiments have been shown to successfully overcome all the mechanical, physical-chemical, and biological barriers in the food chain and to come out into the environment with a quite high number. It has been demonstrated that the same bacterial population can pass the whole cycle without additional introduction of similar populations from the outside.  相似文献   

17.
根据微生态平衡原理,应用三种微生物菌群(系从中国对虾成虾消化道中分离筛选出来的)制成生态制品作为饲料添加剂,对中国对虾出池仔虾进行投喂,实验结果表明:三种生态制品不汉都能显著地提高仔虾的成活率,而且对仔虾的生长也有一定的促进作用。本文对出池仔虾死亡率较高的原因,微生态制剂的促生长机理,以及直接利用出池仔虾进行养成或放流的可能性等问题进行了讨论。  相似文献   

18.
Biosorption of Zn(II) by Thiobacillus ferrooxidans   总被引:1,自引:0,他引:1  
There have been a number of studies considering the possibility of removing and recovering heavy metals from diluted solutions. These are due, principally, because of the commercial value of some metals as well as in the environmental impact caused by them. The traditional methods for removing have several disadvantages when metals are present in concentrations lower than 100 mg/l. Biosorption, which uses biological materials as adsorbents, has been considered as an alternative method. In this work, variables like pH and biomass chemical pretreatment have been studied for its effect on the capacity for zinc biosorption by Thiobacillus ferrooxidans. Also, studies to determinate the time for zinc adsorption were carried out. Results indicate that a capacity as high as 82.61 mg of Zn(II)/g of dry biomass can be obtained at a temperature of 25v°C and that the biosorption process occurs in a time of 30 min.  相似文献   

19.
Certain bacteriophages have been found in live virus vaccines, while a few others have been associated with disease states. Some of these phages have produced abnormal growth of eukaryotic tissue cultures. For this reason bacteriophages phiX-174, MS2, T2 and an isolate from live virus vaccines, phiV-1, were incubated with human cell cultures for examination of chromosomal effects, cell proliferation and viability. Mitogen-stimulated lymphocytes and human embryonic kidney tissue cultures showed no increase in chromosomal abnormalities for high doses of phage-infected versus control cultures. Tritiated-thymidine uptake, correlated with mitotic indices for phage-treated lymphocyte cultures, indicated a reduction in cell division, while 51-chromium release studies showed no cell death occurring in these cultures. This suggested that inhibition of DNA synthesis was occurring in some cells. The presence of phage in the supernate of cells that were exposed to phage suggested the possibility of phage attachment to the plasma membranes of lymphocytes, which may in turn affect the suppression of DNA synthesis.  相似文献   

20.
Fatty acid ethyl esters (FAEE), esterification products of fatty acids and ethanol, have been shown to be mediators of ethanol-induced cell injury and their presence in the blood and tissues is a marker of ethanol intake. Recently, it has been shown that FAEE are produced within seconds of infusion of ethanol into the heart, when using a protocol similar to that used for myocardial ablation. This raises the possibility that the mechanism for the death of myocytes in cardiac ablation involves the generation of toxic FAEE. It has also been recently demonstrated that chronic alcoholics have a high concentration of a specific FAEE species--ethyl oleate. The use of the serum ethyl oleate concentration may be helpful in differentiating binge drinkers from chronic alcoholics.  相似文献   

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