Comparing and combining distance-based and character-based approaches for barcoding turtles

Molecular barcoding can serve as a powerful tool in wildlife forensics and may prove to be a vital aid in conserving organisms that are threatened by illegal wildlife trade, such as turtles (Order Testudines). We produced cytochrome oxidase subunit one (COI) sequences (650 bp) for 174 turtle species and combined these with publicly available sequences for 50 species to produce a data set representative of the breadth of the order. Variability within the barcode region was assessed, and the utility of both distance-based and character-based methods for species identification was evaluated. For species in which genetic material from more than one individual was available (n = 69), intraspecific divergences were 1.3% on average, although divergences greater than the customary 2% barcode threshold occurred within 15 species. High intraspecific divergences could indicate species with a high degree of internal genetic structure or possibly even cryptic species, although introgression is also probable in some of these taxa. Divergences between species of the same genus were 6.4% on average; however, 49 species were <2% divergent from congeners. Low levels of interspecific divergence could be caused by recent evolutionary radiations coupled with the low rates of mtDNA evolution previously observed in turtles. Complementing distance-based barcoding with character-based methods for identifying diagnostic sets of nucleotides provided better resolution in several cases where distance-based methods failed to distinguish species. An online identification engine was created to provide character-based identifications. This study constitutes the first comprehensive barcoding effort for this seriously threatened order.     

siRNA, miRNA and HIV: promises and challenges

Small interfering RNA (siRNA) and microRNA (miRNA) are small RNAs of 18-25 nucleotides (nt) in length that play important roles in regulating gene expression. They are incorporated into an RNA-induced silencing complex (RISC) and serve as guides for silencing their corresponding target mRNAs based on complementary base-pairing. The promise of gene silencing has led many researchers to consider siRNA as an anti-viral tool. However, in long-term settings, many viruses appear to escape from this therapeutical strategy. An example of this may be seen in the case of human immunodeficiency virus type-1 (HIV-1) which is able to evade RNA silencing by either mutating the siRNA-targeted sequence or by encoding for a partial suppressor of RNAi (RNA interference). On the other hand, because miRNA targeting does not require absolute complementarity of base-pairing, mutational escape by viruses from miRNA-specified silencing may be more difficult to achieve. In this review, we discuss stratagems used by various viruses to avoid the cells' antiviral si/mi-RNA defenses and notions of how viruses might control and regulate host cell genes by encoding viral miRNAs (vmiRNAs).     

The case and opportunity for public-supported financial incentives to implement integrated pest management

Food, water, and worker protection regulations have driven availability, and loss, of pesticides for use in pest management programs. In response, public-supported research and extension projects have targeted investigation and demonstration of reduced-risk integrated pest management (IPM) techniques. But these new techniques often result in higher financial burden to the grower, which is counter to the IPM principle that economic competitiveness is critical to have IPM adopted. As authorized by the 2002 Farm Bill and administered by the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS), conservation programs exist for delivering public-supported financial incentives to growers to increase environmental stewardship on lands in production. NRCS conservation programs are described, and the case for providing financial incentives to growers for implementing IPM is presented. We also explored the opportunity and challenge to use one key program, the Environmental Quality Incentives Program (EQIP), to aid grower adoption of IPM. The EQIP fund distribution to growers from 1997 to 2002 during the last Farm Bill cycle totaled approximately 1.05 billion dollars with a portion of funds supporting an NRCS-designed pest management practice. The average percentage of allocation of EQIP funds to this pest management practice among states was 0.77 +/- 0.009% (mean +/- SD). Using Michigan as an example, vegetable and fruit grower recognition of the program's use to implement IPM was modest (25% of growers surveyed), and their recognition of its use in aiding implementation of IPM was improved after educational efforts (74%). Proposals designed to enhance program usefulness in implementing IPM were delivered through the NRCS advisory process in Michigan. Modifications for using the NRCS pest management practice to address resource concerns were adopted, incentive rates for pest management were adjusted, and an expanded incentive structure for IPM technique adoption was tabled for future consideration. The case is strong for using public-supported financial incentives offered by the EQIP to aid grower adoption of IPM as a means to address resource concerns, but current use of the EQIP for this purpose is modest to meager. With appropriate program adjustments and increased grower awareness, USDA NRCS conservation programs, and the EQIP in particular, may provide an important opportunity for growers to increase their use of IPM as a resource conservation and farm management tool.     

我国奶牛乳房炎致病性金黄色葡萄球菌血清型分布

本试验采用玻片凝集法对从临床型乳房炎病乳中分离获得的56株金黄色葡萄球菌进行血清型分型。结果表明336型占67.9%(38/56),5型占7.1%(4/56),8型占3.6%(2/56)。