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1.
Jonathan H. Clarke Judith I. Laurie Harry J. Gilbert Geoffrey P. Hazlewood 《FEMS microbiology letters》1991,83(3):305-309
Cellulomonas fimi genomic DNA encoding xylanase activity has been cloned and expressed in Escherichia coli. As judged by DNA hybridization and restriction analysis, twelve xylanase-positive clones carried a minimum of four different xylanase (xyn) genes. The encoded enzymes were devoid of cellulase activity but three of the four bound to Avicel. 相似文献
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Plant and Soil - Agricultural practices often have persistent effects on soil physicochemical properties and soil biota, which can feedback to influence plant performance. We investigated... 相似文献
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Andrew B. Stein Todd K. Fuller Laurie L. Marker 《Biodiversity and Conservation》2008,17(14):3579-3587
In northcentral Namibia, Waterberg Plateau Park (WPP) is a protected area that acts as a refuge for rare and endangered species,
while the farmlands surrounding the Park are managed for livestock production, but support populations of wildlife for game
farming, trophy hunting, and conservation. During June–October 2006, camera-traps were set within and surrounding WPP to assess
leopard (Panthera pardus) density (n = 19 camera stations and 946 camera-trap-nights). Fortuitously, photographic results (2,265 photos of identifiable mammal
(n = 37) and bird (n = 25) species) allowed us to assess aspects of species diversity and differences among the Park, the farmland areas along
the Waterberg Plateau escarpment, and the flatlands surrounding the escarpment. Species composition among the three areas
was markedly different, and made sense with respect to differences in habitat and management features. Camera-trapping efforts,
although intended for a narrow purpose, may also provide a rather robust record of differences in mammal and bird diversity
in adjacent habitats and can be incorporated into long-term monitoring programs. 相似文献
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Emily A. Sloan Mary F. Kearney Laurie R. Gray Kathryn Anastos Eric S. Daar Joseph Margolick Frank Maldarelli Marie-Louise Hammarskjold David Rekosh 《Journal of virology》2013,87(20):11173-11186
HIV-1 Rev and the Rev response element (RRE) enable a critical step in the viral replication cycle by facilitating the nuclear export of intron-containing mRNAs, yet their activities have rarely been analyzed in natural infections. This study characterized their genetic and functional variation in a small cohort of HIV-infected individuals. Multiple Rev and RRE sequences were obtained using single-genome sequencing (SGS) of plasma samples collected within 6 months after seroconversion and at a later time. This allowed the identification of cognate sequences that were linked in vivo in the same viral genome and acted together as a functional unit. Phylogenetic analyses of these sequences indicated that 4/5 infections were founded by a single transmission event. Rev and RRE variants from each time point were subjected to functional analysis as both cognate pairs and as individual components. While a range of Rev-RRE activities were seen, the activity of cognate pairs from a single time point clustered to a discrete level, which was termed the set point. In 3/5 patients, this set point changed significantly over the time period studied. In all patients, RRE activity was more sensitive to sequence variation than Rev activity and acted as the primary driver of the cognate set point. Selected patient RREs were also shown to have differences in Rev multimerization using gel shift binding assays. Thus, rather than acting as a simple on-off switch or maintaining a constant level of activity throughout infection, the Rev-RRE system can fluctuate, presumably to control replication. 相似文献