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Molecular evolution of the family Camelidae: a mitochondrial DNA study   总被引:1,自引:0,他引:1  
We report the first molecular evolutionary analysis of the family Camelidae by analysing the full DNA sequence of the mitochondrial cytochrome b gene. Estimates for the time of divergence of the Old World (Camelini) and New World (Lamini) tribes obtained from sequence data are in agreement with those derived from the fossil record. The DNA sequence data were also used to test current hypotheses concerning the ancestors of the domesticated llama and alpaca. The results show that hybridization has occurred in the ancestry of both domesticated camelids, obscuring the origin of the domestic species.  相似文献   
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Seven compounds were isolated from the seed of Nigella glandulifera. Their structures were identified as kaempferol-3-O-beta-D-galactopyranosyl (1-->3)-beta-D-glucopyranosyl(1-->3)-beta-D-glucopyranoside (N-I), 2-O-[alpha-D-galactopyranosyl (1-->4)-beta-D-glucopyranosyl]-beta-D-fructofuranoside (N-II), N, N-dimethyl-1, 2-dimethoxy-10, 11-dihydric aporphine quaternary ammonium chloride (N-III), 3-O-[beta-D-xylo-pyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinopyranosyl]- 28-O -[alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl (1-->6) beta-D-glucopyranosyl]-hederagenin (N-IV), sucrose(N-V), beta-sitosterol(N-VI) and cyclolandenol(N-VII). Compounds N-I and N-II are new compounds, named nigeglanoside and nigeglanose, respectively. Apart from ten fatty acids in its oil have also been analysed. It is the first time for the study on chemical constituents of the seed of Nigella glandulifera.  相似文献   
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The majority of equations used to predict values for basal metabolic rates (BMRs) are the result of indirect calorimetry measurements performed in the 1930s and 1950s. To assess the reliability of these equations in predicting the resting energy expenditure (REE) of the children in our community, indirect calorimetry was performed on 92 male and 107 female healthy children 2-3 h postprandial. Each individual was measured for a duration of 15-20 min. The data for analysis were obtained from 5-15 min steady-state periods. Subjects ranged in age from 5 to 16 years. The results were compared with BMRs calculated from the Harris-Benedict equation (Harris J, Benedict F. A biometric study of basal metabolism in man. Washington, DC: Carnegie Institute of Washington, publication no. 279, 1919.), the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) equations, and the equations proposed by Schofield for use by the 1985 FAO/WHO/UNU Nutrition Committee. The values predicted by the FAO/WHO/UNU and Schofield equations were consistent with the measured resting values for all the children in the study population. Ninety-two children weighed between 90-110% of their ideal body weight. When the measured REE and estimated BMR were compared by gender and age in these children, the Schofield equations provided the best estimates. Ninety-four of the study subjects weighed > 110% of their ideal body weight. The predicted estimates by all equations were consistent with the measured values in this subgroup of the population. We conclude that the FAO/WHO/UNU and Schofield equations are reliable estimates of metabolic rate in healthy children when measurement of REE is not possible.  相似文献   
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The effects of 3-aminopropylarsonate, an arsono analogue of GABA, was tested on the development of electrically-kindled amygdala and on the expression of generalized seizure activity in electrically and NMDA fully amygdala-kindled rats. Intra-amygdaloid microinjection of 3-aminopropylarsonate (10 nmol in 0.5 microl injection vehicle) inhibited electrical epileptogenesis by keeping the seizure score at or below stage 1 on the Racine scale, and the afterdischarge duration (ADD) at or below 19.70 +/- 4.59 s. The effect was reversible after withdrawal of the drug, since the animals developed a generalized seizure activity when kindling stimuli continued in the absence of drug. In fully electrically kindled animals with stage 5 amygdala-kindled seizures, the drug increased afterdischarge threshold (ADT) by 30-70%, without any effect on mean seizure score or ADD. The changes were reversible after 7 days. In fully NMDA-kindled rats, intra-amygdala administration of 3-aminopropylarsonate (10 nmol/0.5 microl) 20 min before injection of NMDA (4 nmol/0.5 microl) reduced the seizure score from 3.80 +/- 0.37(5) on the Racine scale to 0.83 +/- 0.40(6) (P < 0.01). The effect was partially reversible after washing with phosphate buffer. 2-Amino-4-arsonobutyrate, the analogue of glutamate, had no effect on seizure score following treatment with the same concentration of the drug and the same route of injection. The inhibitory effect of 3-aminopropylarsonate on NMDA kindled activity was dose-dependent, since higher doses of NMDA reduced the effect of the drug. The effect of 3-aminopropylarsonate was also selective to NMDA receptors since it had no effect on kainate-induced seizures. With both models of kindling, no gross behavioural abnormalities were observed 3-6 months after treatment with the drug. These findings show the potent antiepileptogenic and anti-convulsant activity of the arsonoanalogue of GABA which appears to be non-toxic and therefore potentially useful as the basis for developing a new family of clinically useful anticonvulsants for treating epilepsy.  相似文献   
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A new method is presented that permits a rapid and accurate in vivo evaluation of biofilm formation on surface-modified silicone rubber voice prostheses. The method is based on partial modification of a Groningen button voice prosthesis by exposing half of the prosthesis to an argon plasma. This results in one side of the prosthesis becoming hydrophilic while leaving the unmodified side hydrophobic as a control. Modified prostheses were placed in patients for an evaluation period of approximately 4 weeks. Despite making the silicone rubber surface hydrophilic, biofilm formation was stimulated when compared to unmodified, hydrophobic silicone rubber. Findings show that biofilm formation on voice prostheses is influenced by hydrophobicity of a silicone rubber surface. The method of partial surface modification used was seen to be suitable for demonstrating such influences regardless of nutrition and other variations in the patient's lifestyle. Microbiological analysis of the biofilms on both sides of the prosthesis valve did not show any changes in microbial composition, with Candida albicans, streptococci and staphylococci being the most commonly isolated strains.  相似文献   
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