现代生物技术的发展与血友病甲的治疗

现代生物技术的发展,尤其是蛋白质纯化技术及基因分子生物学技术的发展大大地推动了血友病甲的预防、诊断和治疗。     

Assessing the utility of whole genome amplified DNA for next‐generation molecular ecology

DNA quantity can be a hindrance in ecological and evolutionary research programmes due to a range of factors including endangered status of target organisms, available tissue type, and the impact of field conditions on preservation methods. A potential solution to low‐quantity DNA lies in whole genome amplification (WGA) techniques that can substantially increase DNA yield. To date, few studies have rigorously examined sequence bias that might result from WGA and next‐generation sequencing of nonmodel taxa. To address this knowledge deficit, we use multiple displacement amplification (MDA) and double‐digest RAD sequencing on the grey mouse lemur (Microcebus murinus) to quantify bias in genome coverage and SNP calls when compared to raw genomic DNA (gDNA). We focus our efforts in providing baseline estimates of potential bias by following manufacturer's recommendations for starting DNA quantities (>100 ng). Our results are strongly suggestive that MDA enrichment does not introduce systematic bias to genome characterization. SNP calling between samples when genotyping both de‐novo and with a reference genome are highly congruent (>98%) when specifying a minimum threshold of 20X stack depth to call genotypes. Relative genome coverage is also similar between MDA and gDNA, and allelic dropout is not observed. SNP concordance varies based on coverage threshold, with 95% concordance reached at ~12X coverage genotyping de‐novo and ~7X coverage genotyping with the reference genome. These results suggest that MDA may be a suitable solution for next‐generation molecular ecological studies when DNA quantity would otherwise be a limiting factor.     

Mycorrhizal Limonium Sinuatum (l.) Mill. Enhances Accumulation of Lead and Cadmium

Heavy metals accumulation in soils poses a potential threat to ecosystems, which, in turn, threat human health through food chains. Therefore, remediating polluted sites is important to environment and humanity. In this investigation, statice (L. sinuatum) was exposed to Cd (0, 15, 30, 60 mg kg^?1 soil) or Pb (0, 100, 150, 300 mg kg^?1 soil) in a pot experiment to assess its tolerance to each metal and study its phytoaccumulation capability. The benefits of mycorrhization (mixture of Glomus mosseae and G. intraradices) were also studied simultaneously. Single exposure to Cd or Pb reduced the plant growth, but statice was still relatively tolerant to both metals. The plants accumulated both metals in their roots; little was translocated to the shoots. Total Pb and total Cd accumulated by the roots was approximately 2 and 3 times higher in mycorrhizal than non-mycorrhizal plants (49 versus 147 and 595 versus 956 μg plant^?1) respectively; however, mycorrhization alleviated metal phytotoxicity. The results suggest that statice is a potential candidate to be used as an ornamental plant in lead and cadmium polluted sites, mainly inoculated with arbuscular mycorrhizae. Besides that, it would be useful as a Pb or Cd controlling agent by means of phytostabilization.     

后基因组时代的工业生物技术

简述了工业生物技术的发展背景和意义,分析了基因组学和功能基因组学发展对工业生物技术的推动作用,重点介绍了本期专刊发表的代谢工程、发酵工程以及工业酶与生物催化领域的17篇论文。     

A decade of <Emphasis Type="Italic">Bt</Emphasis> cotton in Chinese fields: Assessing the direct effects and indirect externalities of Bt cotton adoption in China

The objective of this study is to examine whether or not the gains from reduced spraying for bollworms are being sustained more than one decade after the initial adoption in 2007. Based on farm-level data collected by the authors in 1999–2007 in 16 villages from 4 provinces, this study shows that insecticides applied for controlling bollworms have declined. This analysis supports Chinese policy makers’ decision to not require refuges of non-Bt cotton fields. It also suggests that past studies may have underestimated the benefits from adopting Bt technology.     

β-Galactosidase from Lactobacillus pentosus: Purification,characterization and formation of galacto-oligosaccharides

A novel heterodimeric β-galactosidase with a molecular mass of 105 kDa was purified from crude cell extracts of the soil isolate Lactobacillus pentosus KUB-ST10-1 using ammonium sulphate fractionation followed by hydrophobic interaction and affinity chromatography. The electrophoretically homogenous enzyme has a specific activity of 97 U_oNPG/mg protein. The K_m, k_cat and k_cat/K_m values for lactose and o-nitrophenyl-β-D-galactopyranoside (oNPG) were 38 mM, 20 s^-1, 530 M^-1·s^-1 and 1.67 mM, 540 s^-1, 325 000 M^-1·s^-1, respectively. The temperature optimum of β-galactosidase activity was 60–65°C for a 10-min assay, which is considerably higher than the values reported for other lactobacillal β-galactosidases. Mg²⁺ ions enhanced both activity and stability significantly. L. pentosus β-galactosidase was used for the production of prebiotic galacto-oligosaccharides (GOS) from lactose. A maximum yield of 31% GOS of total sugars was obtained at 78% lactose conversion. The enzyme showed a strong preference for the formation of β-(1→3) and β-(1→6) linkages, and the main transgalactosylation products identified were the disaccharides β-D-Galp-(1→6)-D -Glc, β-D-Galp-(1→3)-D -Glc, β-D -Galp-(1→6)-D -Gal, β-D -Galp-(1→3)-D -Gal, and the trisaccharides β-D -Galp-(1→3)-D -Lac, β-D -Galp-(1→6)-D -Lac.     

Daunomycin interaction with DNA: Microcalorimetric studies of the thermodynamics and binding mechanism

Nucleic acids are an important target for many therapeutics. Small molecules that bind to nucleic acids are important in many aspects of medicines, particularly in cancer chemotherapy. In recent years, many studies have utilized polynucleic acids with various sequences to demonstrate the binding mechanism of daunomycin, a potent anticancer drug. This study describes that isothermal titration calorimetry is a useful tool for studying the fundamental binding mechanism systemically. The results suggest that the binding free energy is more favorable when the temperature is increased. The binding entropy contributes to this effect. Furthermore, the amine group on daunomycin contributes electrostatic interaction that induces the binding process. In addition, enthalpy-entropy compensation is also exhibited in the daunomycin-DNA binding mechanism. This study used an easy, convenient method of performing a systemic study in a recognition system. The results from this study provide additional information about microscopic mechanisms for molecular design and molecular recognition.     

Is microbial community composition in boreal forest soils determined by pH,C-to-N ratio,the trees,or all three?

In Fennoscandian boreal forests, soil pH and N supply generally increase downhill as a result of water transport of base cations and N, respectively. Simultaneously, forest productivity increases, the understory changes from ericaceous dwarf shrubs to tall herbs; in the soil, fungi decrease whereas bacteria increase. The composition of the soil microbial community is mainly thought to be controlled by the pH and C-to-N ratio of the substrate. However, the latter also determines the N supply to plants, the plant community composition, and should also affect plant allocation of C below ground to roots and a major functional group of microbes, mycorrhizal fungi. We used phospholipid fatty acids (PLFAs) to analyze the potential importance of mycorrhizal fungi by comparing the microbial community composition in a tree-girdling experiment, where tree belowground C allocation was terminated, and in a long-term (34 years) N loading experiment, with the shifts across a natural pH and N supply gradient. Both tree girdling and N loading caused a decline of ca. 45% of the fungal biomarker PLFA 18:2ω6,9, suggesting a common mechanism, i.e., that N loading caused a decrease in the C supply to ectomycorrhizal fungi just as tree girdling did. The total abundance of bacterial PLFAs did not respond to tree girdling or to N loading, in which cases the pH (of the mor layer) did not change appreciably, but bacterial PLFAs increased considerably when pH increased across the natural gradient. Fungal biomass was high only in acid soil (pH < 4.1) with a high C-to-N ratio (>38). According to a principal component analysis, the soil C-to-N ratio was as good as predictor of microbial community structure as pH. Our study thus indicated the soil C-to-N ratio, and the response of trees to this ratio, as important factors that together with soil pH influence soil microbial community composition.     

白腐真菌生物技术降解氯酚污染物

生物降解是降解氯酚污染物的一条重要的转化途径,白腐真菌是一种高效的生物降解菌种,应用白腐真菌生物技术降解具有毒性和抗降解性的氯酚具有重要意义。本文阐述了白腐菌降解氯酚类污染物的途径,阐述了白腐真菌技术,主要包括酶技术、固定化技术、真菌强化技术、堆肥化和生物反应器等在氯酚污染环境治理中的应用,并概述了近几年白腐菌降解氯酚的研究热点和白腐真菌生物技术的应用趋势。