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2.
The molecular evolution of mammalian Y-linked DNA sequences is of special
interest because of their unique mode of inheritance: most Y- linked
sequences are clonally inherited from father to son. Here we investigate
the use of Y-linked sequences for phylogenetic inference. We describe a
comparative analysis of a 515-bp region from the male sex- determining
locus, Sry, in 22 murine rodents (subfamily Murinae, family Muridae),
including representatives from nine species of Mus, and from two additional
murine genera--Mastomys and Hylomyscus. Percent sequence divergence was
< 0.01% for comparisons between populations within a species and was
0.19%-8.16% for comparisons between species. Our phylogenetic analysis of
12 murine taxa resulted in a single most- parsimonius tree that is highly
concordant with phylogenies based on mitochondrial DNA and allozymes. A
total evidence tree based on the combined data from Sry, mitochondrial DNA,
and allozymes supports (1) the monophyly of the subgenus Mus, (2) its
division into a Palearctic group (M. musculus, M. domesticus, M.
spicilegus, M. Macedonicus, and M. spretus) and an Oriental group (M.
cookii++, M. cervicolor, and M. caroli), and (3) sister-group relationships
between M. spicilegus and M. macedonicus and between M. cookii and M.
cervicolor. We argue that Y- chromosome DNA sequences represent a valuable
new source of characters for phylogenetic inference.
相似文献
3.
Active and passive cation transport and L antigen hertogeneity in low potassium sheep red cells
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Several lines of experimental evidence are presented suggesting that the L antigens in low potassium (LK) sheep red cells are associated with separate Na(+)K(+) pump flux is distinct from the action of anti-L(l) on K(+) leak flux, implying that K(+) leak transport sites may not be converted into active pumps by the L antiserum. Treatment of LK red cells with trypsin completely abolished both the stimulation of K(+) pump flux and the enhancement of the rate of ouabain binding brought about by anti- L. That this effect is due to a total destruction of the L(p) determinant associated with the LK pump was evident from the complete failure of anti-L(p) to bind to trypsinized LK red cells. The L(p) antigen can be effectively protected against the trypsin attack by prior incubation with anti-L, indicating that the sites for antibody binding and trypsin action may be closely adjacent at the structural level. Trypsin treatment, however, did not interfere with anti-L(l) reducing ouabain insensitive K(+) leak influx, nor did it prevent binding of anti-L(ly), the hemolytically active L antibody which is probably identical with anti-L(l). The functional independence of the L(p) and L(l) sites was documented by the observation that anti-L(l) still reduced K(+) leak influx in LK cells with experimentally induced high potassium concentrations, at which K(+) pump flux is fully suppressed, whether or not anti-L(p) was binding to the L(p) antigen associated with the LK pump. 相似文献
4.
MNK Clottey R Asmah PK Ofori-Danson MY Ameworwor AY Karikari 《African Journal of Aquatic Science》2016,41(4):473-480
The effects of cage fish farming on physico-chemical and bacteriological water quality in Lake Volta, Ghana, were investigated in 2013–2014. Farmed and unfarmed (control) areas of the lake were selected for monitoring. Nutrients, temperature, dissolved oxygen, conductivity, turbidity, pH, total coliforms, Pseudomonas and Vibrio spp. in the water were monitored monthly. Analyses of the water samples were carried out according to standard procedures. Physico-chemical quality of the water in both farm and control sites were within ranges typical of minimally impacted water and did not vary significantly between the two contrasting sites. The bacteriological analysis, however, revealed contamination of the lake water by fish farming. The bacterial counts at the farmed sites were significantly higher (p < 0.05) than those of the control sites, with figures at the farmed sites ranging from 132 to 1 708 cfu 100 ml?1 for total coliforms, 514 to 5 170 cfu 100 ml?1 Pseudomonas spp. and 14 to 516 cfu 100 ml?1 for Vibrio spp. The results suggested that cage fish farming has increased bacterial loads in the lake water, but has had minimal impact on its physico-chemical quality. 相似文献
5.
Aletaha D Nell VP Stamm T Uffmann M Pflugbeil S Machold K Smolen JS 《Arthritis research & therapy》2005,7(4):R796-R806
Introduction
Frequent assessments of rheumatoid arthritis (RA) disease activity allow timely adaptation of therapy, which is essential in preventing disease progression. However, values of acute phase reactants (APRs) are needed to calculate current composite activity indices, such as the Disease Activity Score (DAS)28, the DAS28-CRP (i.e. the DAS28 using C-reactive protein instead of erythrocyte sedimentation rate) and the Simplified Disease Activity Index (SDAI). We hypothesized that APRs make limited contribution to the SDAI, and that an SDAI-modification eliminating APRs – termed the Clinical Disease Activity Index (CDAI; i.e. the sum of tender and swollen joint counts [28 joints] and patient and physician global assessments [in cm]) – would have comparable validity in clinical cohorts. 相似文献6.
There is increasing evidence for beneficial effects of early DMARD (disease-modifying antirheumatic drug) therapy over delayed
treatment in patients who present with arthritis of recent onset. However, no universal consensus exists concerning the choice
of initial drug or whether single drugs or combinations should be given as initial treatments. Recent studies have focused
on the benefits of various strategies in which treatments were tailored to achieve low levels of disease activity, as assessed
using validated response criteria. These studies demonstrated superiority of 'aggressive' over 'conventional' approaches.
Whether the inclusion of tumour necrosis factor antagonists or other biologic targeted therapies in such strategies confers
additional benefits in terms of improved long-term outcomes must be clarified by further studies. Assessment of risks in the
individual patient, allowing individual 'tailoring' of the initial treatment, would be desirable. 相似文献
7.
The development of valid animal models of learning is especially important since learning is critical for nearly all aspects of human behavior and identifying appropriate surrogates provides additional opportunity to study various aspects of learning. Examining the factors that affect learning is often complicated by the need to administer the same task repeatedly across experimental conditions. Incremental repeated acquisition (IRA) tasks have been used extensively in animal research because they circumvent this problem by requiring a subject to learn different response chains repeatedly across sessions. The present study examined the association of age, sex of the participant, and IQ on the performance of an incremental repeated acquisition task in 837 children, aged 5-13 years. This task required children to learn to press four response levers in a specific sequence that was randomly chosen. Illumination of colored indicator lights signaled position in the required response chain. Initially, for the first link, only one of the four levers was correct: a response to it resulted in the delivery of a monetary reinforcer (5 cents). After mastery of the first link (i.e. three correct presses), the children were presented with a two-link response chain: a different lever had to be pressed before pressing the previously correct lever. After mastery of the two-link chain, the response chain length was once again increased, and so on until a response chain consisting of six links was completed or until the task timed out. Older children and children with higher IQs mastered longer response chain lengths and were more accurate in performance of this learning task than younger children. In addition, older children and children with higher IQs had higher effective response rates and lower ineffective response rates. No significant effects of the sex of the participant were demonstrated for any of the variables on this task, except overall response rate. The results indicate that this test is sensitive to developmental variables in children, with the degree of sensitivity of certain dependent variables being age-dependent. Characterization of performance of this task by humans facilitates comparisons with animal models employing the same task, thus enhancing its translational utility. 相似文献
8.
Vitamin D deficiency is a previously unreported complication of therapy with hypnotics, and we here report a case of osteomalacia associated with long-term glutethimide administration. There was evidence of pronounced hepatic enzyme induction, and the plasma half-time of 3H vitamin D3 was decreased by this drug. In addition, raised levels of serum gamma-glutamyl transpeptidase, 5-nucleotidase, and leucine aminopeptidase were observed and the patient excreted large amounts of xylulose. These changes were reversed by stopping the glutethimide. 相似文献
9.
10.
Louis Tong Jaime Chew Henry Yang Leonard PK Ang Donald TH Tan Roger W Beuerman 《BMC medical genomics》2009,2(1):1-21