流行性出血热病毒R22株cDNA克隆及其特异性鉴定

用家鼠型流行性出血热病毒R22株RNA,经polyA接尾,以Oligo-dT做引物,合成cDNA。用pUC18为载体转染E.coli Mc1061,建立cDNA克隆。再经菌落杂交,选择病毒特异性的5个阳性克隆制成缺口翻译探针,与病毒RNA3个片段进行反杂交,确定RNA片段的特异性。结果表明,3个克隆为中(M)片段的cDNA,另两个分别为大(L)和小(S)片段cDNA。核苷酸序列分析证明,克隆的DNA中含病毒特异的核苷酸序列。     

Thumb replantation after cardiac transplantation

Generally, severe medical illnesses, including chronic immunosuppression and heavy steroid use, have been deemed relative contraindications for replantation surgery. We report the successful replantation of an amputated thumb in a patient who had previously undergone heart transplantation and was on therapeutic immunosuppression. Despite extensive soft-tissue damage and joint involvement, thumb function and sensibility returned to acceptable levels. This case demonstrates that digital bony union, tendon repair healing, and nerve regeneration are not significantly altered by the standard immunosuppressive regimen following major organ transplant. The implications raised by this case for possible transplantation of allograft digits or limbs are discussed in detail.     

Repeated Evolution of Inactive Pseudonucleases in a Fungal Branch of the Dis3/RNase II Family of Nucleases

The RNase II family of 3′–5′ exoribonucleases is present in all domains of life, and eukaryotic family members Dis3 and Dis3L2 play essential roles in RNA degradation. Ascomycete yeasts contain both Dis3 and inactive RNase II-like “pseudonucleases.” The latter function as RNA-binding proteins that affect cell growth, cytokinesis, and fungal pathogenicity. However, the evolutionary origins of these pseudonucleases are unknown: What sequence of events led to their novel function, and when did these events occur? Here, we show how RNase II pseudonuclease homologs, including Saccharomyces cerevisiae Ssd1, are descended from active Dis3L2 enzymes. During fungal evolution, active site mutations in Dis3L2 homologs have arisen at least four times, in some cases following gene duplication. In contrast, N-terminal cold-shock domains and regulatory features are conserved across diverse dikarya and mucoromycota, suggesting that the nonnuclease function requires these regions. In the basidiomycete pathogenic yeast Cryptococcus neoformans, the single Ssd1/Dis3L2 homolog is required for cytokinesis from polyploid “titan” growth stages. This phenotype of C. neoformans Ssd1/Dis3L2 deletion is consistent with those of inactive fungal pseudonucleases, yet the protein retains an active site sequence signature. We propose that a nuclease-independent function for Dis3L2 arose in an ancestral hyphae-forming fungus. This second function has been conserved across hundreds of millions of years, whereas the RNase activity was lost repeatedly in independent lineages.     

Association of Weather and Anthropogenic Factors for Transmission of Japanese Encephalitis in an Endemic Area of India

Weather and anthropogenic factors are important determinants for Japanese encephalitis (JE) transmission. During 2008–2010, an increasing trend of JE was observed in Dibrugarh district of Northeast India. The JE cases were found to be clustered between June to October in each year. Monthly minimum temperature and rainfall were significantly associated with JE transmission at 1 and 2 months lagged. However, the relationship was more prominent at a lag of 1 month than that of two. Regression analysis suggested that rainfall, minimum and maximum temperature, and relative humidity at 6:00 h are significant predictors (P < 0.05) of quarterly occurrence of JE cases. Additional anthropogenic risk factors including the conditions such as pig sty/cattle shed around and lower part of the houses and proximity of rice field to the dwelling houses (P < 0.05) were also found to be predictors for JE occurrence. Meteorological and anthropogenic risk factors can be used to forecast JE outbreaks in Assam which in turn can help the local health authorities to protect communities in JE prone areas.     

Mycobacterium tuberculosis carbon and nitrogen metabolic fluxes

Mycobacterium tuberculosis (Mtb) is one of the most formidable pathogens causing tuberculosis (TB), a devastating infectious disease responsible for the highest human mortality and morbidity. The emergence of drug-resistant strains of the pathogen has increased the burden of TB tremendously and new therapeutics to overcome the problem of drug resistance are urgently needed. Metabolism of Mtb and its interactions with the host is important for its survival and virulence; this is an important topic of research where there is growing interest in developing new therapies and drugs that target these interactions and metabolism of the pathogen during infection. Mtb adapts its metabolism in its intracellular niche and acquires multiple nutrient sources from the host cell. Carbon metabolic pathways and fluxes of Mtb has been extensively researched for over a decade and is well-defined. Recently, there has been investigations and efforts to measure metabolism of nitrogen, which is another important nutrient for Mtb during infection. This review discusses our current understanding of the central carbon and nitrogen metabolism, and metabolic fluxes that are important for the survival of the TB pathogen.     

Growth-associated production of poly-3-hydroxybutyrate byBacillus mycoides

Bacillus mycoides strain RIJ B-017, a growth-associated poly-3-hydroxybutyrate (PHB) producer was grown on sucrose-containing media. PHB accumulated in cells up to 72% of dry cell mass. The overall maximum value of PHB yield (Y _p/s) and productivities (Q _p andq _p) 250 mg_p/g_s, 120 mg_p L⁻¹ h⁻¹ and 30 mg_p g_x ⁻¹ h⁻¹, respectively, were obtained at 15 g/L sucrose. Differential scanning calorimeter heating curve showed two peaks, one at 95.9 °C and another at 165.4°C with a shoulder around 154.6 °C. The viscosity-average molar mass in chloroform at 27°C was 505 kDa. The carbon content of PHB was 55.4% of the mass.     

Synthesis, absolute stereochemistry and molecular design of the new antifungal and antibacterial antibiotic produced by Streptomyces sp.201

The absolute stereochemistry of the new antifungal and antibacterial antibiotic produced by Streptomyces sp.201 has been established by achieving the total synthesis of the product. A series of analogues have also been synthesized by changing the side chain and their bioactivity assessed against different microbial strains. Among them, 1e (R = C8H17) was found to be the most potent with MIC of 8 microg/mL against Mycobacterium tuberculosis, 12 microg/mL against Escherichia coli and 16 microg/mL against Bacillus subtilis 6 microg/mL against Proteus vulgaris. This was followed by 1b (R = C5H11) with MIC of 10-20 microg/mL range and 1d (R = C7H15) with MIC of 14-24 g/mL, whereas 1a (R = C4H9) and 1f (R = C18H35) were found to be completely inactive. Besides, 1c (R = C6H13) showed certain extent of antibacterial activity in the range of 24-50 microg/mL. Mycobacterium tuberculosis was very sensitive to 1e (R = C8H17) with MIC of 8 microg/mL. Antifungal activity of analogues 1d (R = C7H15) and 1e, (R = C8H17) against Fusarium oxysporum and Rhizoctonia solani were found promising with MFCs in the 15-18 microg/mL range.