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Background

All viruses in the family Bunyaviridae possess a tripartite genome, consisting of a small, a medium, and a large RNA segment. Bunyaviruses therefore possess considerable evolutionary potential, attributable to both intramolecular changes and to genome segment reassortment. Hantaviruses (family Bunyaviridae, genus Hantavirus) are known to cause human hemorrhagic fever with renal syndrome or hantavirus pulmonary syndrome. The primary reservoir host of Sin Nombre virus is the deer mouse (Peromyscus maniculatus), which is widely distributed in North America. We investigated the prevalence of intramolecular changes and of genomic reassortment among Sin Nombre viruses detected in deer mice in three western states.

Methods

Portions of the Sin Nombre virus small (S) and medium (M) RNA segments were amplified by RT-PCR from kidney, lung, liver and spleen of seropositive peromyscine rodents, principally deer mice, collected in Colorado, New Mexico and Montana from 1995 to 2007. Both a 142 nucleotide (nt) amplicon of the M segment, encoding a portion of the G2 transmembrane glycoprotein, and a 751 nt amplicon of the S segment, encoding part of the nucleocapsid protein, were cloned and sequenced from 19 deer mice and from one brush mouse (P. boylii), S RNA but not M RNA from one deer mouse, and M RNA but not S RNA from another deer mouse.

Results

Two of 20 viruses were found to be reassortants. Within virus sequences from different rodents, the average rate of synonymous substitutions among all pair-wise comparisons (πs) was 0.378 in the M segment and 0.312 in the S segment sequences. The replacement substitution rate (πa) was 7.0 × 10-4 in the M segment and 17.3 × 10-4 in the S segment sequences. The low πa relative to πs suggests strong purifying selection and this was confirmed by a Fu and Li analysis. The absolute rate of molecular evolution of the M segment was 6.76 × 10-3 substitutions/site/year. The absolute age of the M segment tree was estimated to be 37 years. In the S segment the rate of molecular evolution was 1.93 × 10-3 substitutions/site/year and the absolute age of the tree was 106 years. Assuming that mice were infected with a single Sin Nombre virus genotype, phylogenetic analyses revealed that 10% (2/20) of viruses were reassortants, similar to the 14% (6/43) found in a previous report.

Conclusion

Age estimates from both segments suggest that Sin Nombre virus has evolved within the past 37–106 years. The rates of evolutionary changes reported here suggest that Sin Nombre virus M and S segment reassortment occurs frequently in nature.  相似文献   
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Background  

Cerebellar granule cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of granule cell precursors to the overexpression of Hoxa2, which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment?  相似文献   
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Li Y  Zheng H  Witt CM  Roll S  Yu SG  Yan J  Sun GJ  Zhao L  Huang WJ  Chang XR  Zhang HX  Wang DJ  Lan L  Zou R  Liang FR 《CMAJ》2012,184(4):401-410

Background:

Acupuncture is commonly used to treat migraine. We assessed the efficacy of acupuncture at migraine-specific acupuncture points compared with other acupuncture points and sham acupuncture.

Methods:

We performed a multicentre, single-blind randomized controlled trial. In total, 480 patients with migraine were randomly assigned to one of four groups (Shaoyang-specific acupuncture, Shaoyang-nonspecific acupuncture, Yangming-specific acupuncture or sham acupuncture [control]). All groups received 20 treatments, which included electrical stimulation, over a period of four weeks. The primary outcome was the number of days with a migraine experienced during weeks 5–8 after randomization. Our secondary outcomes included the frequency of migraine attack, migraine intensity and migraine-specific quality of life.

Results:

Compared with patients in the control group, patients in the acupuncture groups reported fewer days with a migraine during weeks 5–8, however the differences between treatments were not significant (p > 0.05). There was a significant reduction in the number of days with a migraine during weeks 13–16 in all acupuncture groups compared with control (Shaoyang-specific acupuncture v. control: difference –1.06 [95% confidence interval (CI) –1.77 to –0.5], p = 0.003; Shaoyang-nonspecific acupuncture v. control: difference –1.22 [95% CI –1.92 to –0.52], p < 0.001; Yangming-specific acupuncture v. control: difference –0.91 [95% CI –1.61 to –0.21], p = 0.011). We found that there was a significant, but not clinically relevant, benefit for almost all secondary outcomes in the three acupuncture groups compared with the control group. We found no relevant differences between the three acupuncture groups.

Interpretation:

Acupuncture tested appeared to have a clinically minor effect on migraine prophylaxis compared with sham acupuncture.

Trial Registration:

Clinicaltrials.gov NCT00599586About 6%–8% of men and 16%–18% of women in the United States and England experience migraines, with or without an aura.1,2 A prevalence of 1% has been reported in mainland China,3 compared with 4.7% in Hong Kong and 9.1% in Taiwan.4,5 A recent Cochrane meta-analysis suggests that acupuncture as migraine prophylaxis is safe and effective and should be considered as a treatment option for willing patients.6Although the specific effects acupuncture are controversial, acupuncture, as it is currently practised, clearly differentiates between real acupuncture points and nonacupuncture points. The Chinese Government launched the National Basic Research Program to obtain more data about the specificity of acupuncture points.7Trials from Italy and Brazil8,9 showed that acupuncture was more effective than sham acupuncture in preventing migraines, but other trials have reported no differences.1013 There is no evidence that one acupuncture strategy is more effective than another for treating migraines. According to acupuncture theory, a headache on the lateral side is usually defined as a Shaoyang headache. In Jinkuiyi,14 migraines are said to affect the yang meridians (including the Taiyang, Yangming and Shaoyang meridians). In Lingshu,15 the Shaoyang meridians are said to go through the lateral side of the body, therefore the Shaoyang meridians are thought to be superior for treating migraines. Some points on the Shaoyang meridians are regarded as being more specific for migraines than other points.16Our aim was to investigate whether acupuncture at specific acupuncture points was more efficacious in preventing migraine than sham acupuncture at nonacupuncture points. We also investigated whether the efficacy varied when acupuncture points along different meridians or points along the same meridian were used.  相似文献   
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Synthesis of dechlorinase in Streptomyces sp. M7 was induced when the microorganism was grown in the presence of lindane (γ-hexachlorocyclohexane) as the only carbon source. Activity of cells grown with lindane was about four and half times higher compared to cells grown with glucose. Maximum dechlorinase activity was observed at 30°C in alkaline conditions pH (7.9) and the enzyme did not show cation dependency. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed one differential band with a molecular weight similar to serum albumin (M r 66,200), which corresponded to polynucleotide phosphorylase, an enzyme that plays an important role in the regulation system and could be involved in the regulation of the dechlorinase gene. Detected in cell-free extracts were γ-pentachlorocyclohexene and 1,3,4,6-tetrachloro-1,4-cyclohexadiene, both being products of the dechlorinase activity. This is the first time that the presence of an enzyme with dechlorinase activity has been demonstrated in an actinomycete strain isolated in Tucumán, Argentina. Characteristics of this enzyme revealed that Streptomyces sp. M7 could be useful in the future in bioremediation of soil or as a biosensor.  相似文献   
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alpha-1-Antitrypsin has been isolated and purified from the serum of an individual with the Pi S phenotype whose serum contains only 50--60% as much alpha-1-antitrypsin as normal M-type serum. The preparation was homogeneous by the criteria of sodium dodecyl sulfate polyacrylamide gel electrophoresis and sedimentation equilibrium ultracentrigufation. When analyzed in the ultracentrifuge, the S-type alpha-1-antitrypsin exhibited a molecular weight of 47,500 which was essentially the same as that of the M-type (47,300) and the Z-type (47,500) alpha-1-antitrypsin. The S-type alpha-1-antitrypsin contains 15.2% carbohydrate consisting of 16.4 residues/mol of N-acetylglucosamine, 7.8 residues/mol of mannose. 6.7 residues/mol of galactose and 7.1 residues/mol of sialic acid which is essentially the same as the carbohydrate composition of the M-type alpha-1-antitrypsin. In addition, M- and S-type alpha-1-antitrypsin have very similar amino acid compositions.  相似文献   
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Abstract: Two Swedish zinc sulfide ores, from Saxberget (S-ore) and Kristineberg (K-ore), respectively, were compared for bacterial leachability with respect to grain size, and additions of ammonia, iron and phosphate. 87 days of column leaching resulted in 2.4–3.2 g Zn/I in solution and 1.5–1.9 g Cu/I from the K-ore and 1.2–5.3 g Zn/l and 0–0.3 g Cu/l from the S-ore. The highest values were achieved for grain sizes between 16 and 64 mm. Ammonium showed a stimulating effect on bacterial leaching, increasing leached Zn in the K-ore from 27% to 35% and from 7% up to 70% Zn in the S-ore after 53 days of batch leaching. Phosphate additions showed negative effects. Iron additions had a positive effect for the K-ore, increasing the leaching from 48% to 78% Zn at an addition of 6 mg Fe2+.  相似文献   
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