首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   30篇
  免费   2篇
  国内免费   1篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2016年   2篇
  2015年   4篇
  2013年   1篇
  2012年   3篇
  2011年   1篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   4篇
  2006年   1篇
  2005年   1篇
  2004年   3篇
  2002年   2篇
  1999年   1篇
  1988年   1篇
  1979年   1篇
排序方式: 共有33条查询结果,搜索用时 312 毫秒
1.
If we are to make meaningful and measurable progress in restoring New Zealand's biological heritage by 2050, a range of fundamental issues need to be addressed. These relate not just to restoration science but also to building ecosystem resilience in the wider socio‐economic and cultural context within which restoration occurs.  相似文献   
2.
3.
Continuous protein production with baculovirus expression vectors in insect-cell bioreactors is characterized by a dramatic drop in heterologous protein production within a few weeks. This is mainly due to the spontaneous deletion of the heterologous gene(s) from the baculovirus genome and/or to the rapid accumulation of defective interfering baculoviruses (DIs). Cell culture experiments with bacmid-derived baculoviruses showed that spontaneous deletions in the foreign bacterial artificial chromosome (BAC) sequences readily occurred. These deletions correlated with a low density of baculovirus homologous (repeat) regions (hrs), which are located dispersed throughout the baculovirus genome and are believed to act as origins of viral DNA replication (oris). To test the hypothesis that deletions are more likely to occur in regions with a low ori density, the properties of bacmid-derived baculoviruses with an additional hr in the unstable BAC sequences were compared to the standard bacmid-derived baculovirus in a continuous cascaded insect-cell bioreactor configuration. All viruses were equipped with a green fluorescent protein (GFP) gene and a gene encoding the classical swine fever virus E2 glycoprotein (CSFV-E2). The insertion of an extra hr in the BAC vector led to improved genetic stability of adjacent sequences, resulting in prolonged protein expression. The maintenance of the BAC sequences appeared to be dependent on the orientation of the inserted hr. The advantages of the utilization of hrs to improve the stability of baculovirus expression vectors for the large-scale protein production in insect-cell bioreactors are discussed.  相似文献   
4.
5.
A pluralist and cross‐cultural approach that accommodates differing values while encouraging the collaboration and social cohesion necessary for the complex task of ecological restoration is needed. We used qualitative and quantitative analyses to investigate value assigned to biocultural restoration of coastal forests in northern New Zealand by 26 interviewees from three groups (environmental managers, Māori community members, and community project leaders). Māori community members primarily emphasized the importance of Cultural Stewardship and Use in the restoration process, while placing less emphasis on Ecological Integrity. Otherwise, all participants shared common trends, culminating in three interrelated value sets: (1) Personal Engagement, (2) Connection, and (3) the generation and transfer of Knowledge & Wisdom. These values demonstrate that restoration's benefits to people and community are as significant as its reparations of ecological components. Despite differences, all stakeholders were united in a broadly common goal to restore socio‐ecological systems. Their knowledge and shared passion for conservation signal enormous promise for accelerated and effective restoration of coastal forests, if it is conducted using a pluralistic approach. Because some values expressed were intangible and complex, with cross‐cultural dimensions, current valuation tools used by ecological economists to guide management investment fail to adequately account for, in particular, Māori values of ecological restoration.  相似文献   
6.
Cultural tourism is often described as inciting visited populations to adapt elements of their culture to the visitors' tastes instead of displaying their real way of life or identity. Even when researchers adopt a constructivist approach to authenticity, they often assume that it is defined according to the criteria or expectations of the tourists. In this paper, I analyse three Māori cultural shows in New Zealand, and explore the way cultural authenticity is defined in tourist interactions. I review the arguments in favour of rejecting the opposition between ‘inauthentic’ staged culture and ‘authentic’ daily life. My study tends to indicate that if authenticity is better described as a social construction, the host society might be more active in this process than visitors.  相似文献   
7.
Song H  Niederweis M 《Gene》2007,399(2):112-119
Mycobacteria contain a large number of redundant genes whose functions are difficult to analyze in mutants because there are only two efficient antibiotic resistance genes available for allelic exchange experiments. Sequence-specific recombinbases such as the Flp recombinase can be used to excise resistance markers. Expression of the flp(e) gene from Saccharomyces cerevisiae is functional for this purpose in fast-growing Mycobacterium smegmatis but not in slow-growing mycobacteria such as M. bovis BCG or M. tuberculosis. We synthesized the flp(m) gene by adapting the codon usage to that preferred by M. tuberculosis. This increased the G+C content from 38% to 61%. Using the synthetic flp(m) gene, the frequency of removal of FRT-hyg-FRT cassette from the chromosome by the Flp recombinase was increased by more than 100-fold in M. smegmatis. In addition, 40% of all clones of M. bovis BCG had lost the hyg resistance cassette after transient expression of the flp(m) gene. Sequencing of the chromosomal DNA showed that excision of the FRT-hyg-FRT cassette by Flp was specific. These results show that the flp(m) encoded Flp recombinase is not only an improved genetic tool for M. smegmatis, but can also be used in slow growing mycobacteria such as M. tuberculosis for constructing unmarked mutations. Other more sophisticated applications in mycobacterial genetics would also profit from the improved Flp/FRT system.  相似文献   
8.
9.
10.
Magnoni F  Sala C  Forti F  Dehò G  Ghisotti D 《Plasmid》2006,56(3):216-222
The genetic element P4 propagates in its host Escherichia coli both as a satellite phage and as a plasmid. Two partially overlapping replicons coexist, namely replicon I and replicon II. The former is composed of two sites, ori1 and crr, and depends on P4 alpha gene product for replication. The P4 alpha protein has primase and helicase activities, and binds specifically to both ori1 and crr. Replicon II is composed of two sites, ori2 and crr, and its replication also depends on P4 alpha primase and helicase activities. In replicon II, the alpha protein binds only crr. Here we show that for replicon II the relative orientation of ori2 and crr is essential for replication to occur. Furthermore we delimit ori2 to a 22 bp region (6234-6255), internal to the alpha gene, sufficient for replicon II replication. We mutagenized this region and identified two mutants, which carry one and two base substitutions, respectively, that prevent replicon II replication. In electrophoretic mobility shift experiments of ori2, ori1, and crr DNA fragments with E. coli extracts, ori2 was not shifted, whereas both ori1 and crr were specifically bound, suggesting that other host protein(s), beside P4 alpha, are able to bind to these cis essential regions. Apparently, no binding to ori2 could be identified, thus suggesting that neither alpha nor other bacterial proteins specifically bind to this region.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号