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41.
In order to develop BiodiversityKnowledge, a Network of Knowledge working at the European science–policy interface for biodiversity and ecosystem services, we conducted three trial assessments. Their purpose was to test structure and processes of the knowledge synthesis function and to produce knowledge syntheses. The trial assessments covered conservation and management of kelp ecosystems, biological control of agricultural pests, and conservation and multifunctional management of floodplains. Following the BiodiversityKnowledge processes, we set up expert consultations, systematic reviews, and collaborative adaptive management procedures in collaboration with requesters, policy and decision-makers, stakeholders, and knowledge holders. Outputs included expert consultations, systematic review protocols, a group model and a policy brief. Important lessons learned were firstly that the scoping process, in which requesters and experts iteratively negotiate the scope, scale and synthesis methodology, is of paramount importance to maximize the scientific credibility and policy relevance of the output. Secondly, selection of a broad array of experts with diverse and complementary skills (including multidisciplinary background and a broad geographical coverage) and participation of all relevant stakeholders is crucial to ensure an adequate breath of expertise, better methodological choices, and maximal uptake of outcomes: Thirdly, as the most important challenge was expert and stakeholder engagement, a high visibility and reputation of BiodiversityKnowledge, supported by an incentive system for participation, will be crucial to ensure such engagement. We conclude that BiodiversityKnowledge has potential for a good performance in delivering assessments, but it requires adequate funding, trust-building among knowledge holders and stakeholders, and a proactive and robust interface with the policy and decision making community.  相似文献   
42.
The present study was designed (1) to determine whether a free jejunal transfer in a large animal model can develop collateral circulation that is adequate to maintain viability after division of the pedicle and (2) to determine the earliest time pedicle ligation is safe after transplantation. A 15-cm jejunal segment was transferred to the necks of 18 dogs weighing 25 to 35 kg. The bowel segment was inset longitudinally under the skin on one side of the neck, partially covered by the neck muscles, and the mesenteric vessels were anastomosed to recipient vessels in the neck. The proximal and distal bowel stomas were exteriorized through skin openings 12 cm apart and matured. The dogs were subjected to ligation of the vascular pedicle at different intervals: postoperative day 7 (group I, n = 3), day 14 (group II, n = 5), day 21 (group III, n = 5), and day 28 (group IV, n = 5). Blood perfusion was measured in the proximal and distal bowel stomas before pedicle division (control) and 24 hours later using hydrogen gas clearance and fluorescein dye. Bowel necrosis was analyzed using planimetry. The bowel was also stained with hematoxylin and eosin and factor VIII, and new blood vessels were counted. Mean values (+/- standard deviation) were compared with control values for each test and with normal values in the intact bowel using analysis of variance with Neumann-Keuls post-hoc test for multiple comparisons. No jejunal free flaps survived when the vascular pedicle was divided 1 week postoperatively. Bowel survival was 60 percent at 2 weeks, 83 percent at 3 weeks, and 100 percent at 4 weeks. Hydrogen gas clearance values (ml/min/100 g) were 49.6 +/- 8.7 in the mucosa of the intraabdominal jejunum and 37.9 +/- 9.4 in the jejunum that was transferred to the neck before division of the pedicle. Twenty-four hours after pedicle division, hydrogen gas clearance values were 2.8 +/- 6.4 in group I (p < 0.05), 22.4 +/- 12.4 in group II, 23.9 +/- 9.3 in group III, and 34.2 +/- 7.5 in group IV. FluoroScan readings in the transferred jejunum were 201 +/- 7.2 in the control group, 9.3 +/- 2.8 in group I (p < 0.05), 79.1 +/- 10.6 in group II, 66.2 +/- 7.3 in group III, and 164 +/- 11.9 in group IV. New vessel formation as identified by factor VIII staining correlated with increasing bowel perfusion and flap survival rate. Bowel neovascularization, perfusion, and survival increased progressively 1 week after transfer. Significant portions of the transferred bowel will neovascularize and survive as early as 2 weeks postoperatively. However, a minimum of 4 weeks before ligation of the pedicle is necessary to maximize flap perfusion and guarantee survival.  相似文献   
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Background  

Structural genomics (SG) projects aim to determine thousands of protein structures by the development of high-throughput techniques for all steps of the experimental structure determination pipeline. Crucial to the success of such endeavours is the careful tracking and archiving of experimental and external data on protein targets.  相似文献   
46.
Nucleic acid sequences of the second exons of HLA-DRB1, –DRB3/4/5, –DQB1, and –DQA1 genes were determined from 43 homozygous cell lines, representing each of the known class II haplotypes, and from 30 unrelated Caucasian subjects, comprising 60 haplotypes. This systematic sequence analysis was undertaken in order to a) determine the existence of sequence microheterogeneity among cell lines which type as identical by methods other than sequencing; b) determine whether direct sequencing of class II genes will identify the presence of more extensive sequence polymorphism at the population level than that identified with other typing methods; c) accurately determine the molecular composition of the known class II haplotypes; and d) study their evolutionary relatedness by maximum parsimony analysis. The identification of seven previously unidentified haplotypes carrying five new allelic amino acid sequences suggests that sequence microheterogeneity at the population level may be more frequent than previously thought. Maximum parsimony analysis of these haplotypes allowed their evolutionary classification and indicates that the higher mutation rate at DRB1 compared to DQB1 loci in most haplotypic groups is inversed in specific haplotype lineages. Furthermore, the extent and localization of gene conversions and point mutations at class II loci in the evolution of these haplotypes is significantly different at each locus. Identification of additional HLA class II molecular microheterogeneity suggests that direct sequence analysis of class II HLA genes can uncover new allelic sequences in the population and may represent a useful alternative to current typing methodologies to study the effects of sequence allelism in organ transplantation.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers M35890 through M35953.  相似文献   
47.
在人参(Panax ginseng C.A.Meyer)悬浮细胞质膜上测出了NAD(P)H氧化酶活性。这类NAD(P)H氧化酶活性可以被金瓜炭疽细胞壁激发子(Cle)诱导。Cle处理还能诱导人参悬浮细胞的氧进发、促进人参悬浮细胞的皂苷合成、提高苯丙氨酸解氨酶(PAL)的活力、以及诱导查尔式酮酶(CHS)的累积和细胞壁上抗性相关蛋白基因脯氨酸富裕蛋白基因hrgp(Hydroxyprolin-rich glycoproleins)的表达。当用哺乳动物白细胞质膜NADPH氧化酶的特异性抑制剂二亚苯基碘(Diphenylene iodonium,DPI)与奎吖因(quinacrine)预处理人参悬浮细胞30 min 后,Cle诱导的H2O2释放与Cle激活的质膜NAD(P)H氧化酶活性被抑制,同时Cle诱导的PAL活性及CHS的积累下降,皂苷合成与hrgp的表达被抑制。由此推测:人参细胞质膜NAD(P)H氧化酶与哺乳动物白细胞质膜NADPH氧化酶有很大的相似性。在Cle激发人参悬浮细胞产生氧进发的过程中,NAD(P)H氧化酶活性被诱导从而导致H2O2的产生,H2O2作为第二信使,激活苯丙氨酸途径,诱发人参皂苷的合成及hrgp防御基因的表达。这一过程中还涉及到Ca2+内流,胞内Ca2+浓度的升高,蛋白磷酸化与去磷酸化。人参细胞质膜NAD(P)H氧化酶在人参细胞对Cle的反应过程中起一种介导作用。因此可能存在由Cle刺激,NAD(P)H氧化酶被诱导,H2O2释放,到人  相似文献   
48.
L1 retroposons are represented in mice by subfamilies of interspersed sequences of varied abundance. Previous analyses have indicated that subfamilies are generated by duplicative transposition of a small number of members of the L1 family, the progeny of which then become a major component of the murine L1 population, and are not due to any active processes generating homology within preexisting groups of elements in a particular species. In mice, more than a third of the L1 elements belong to a clade that became active approximately 5 Mya and whose elements are > or = 95% identical. We have collected sequence information from 13 L1 elements isolated from two species of voles (Rodentia: Microtinae: Microtus and Arvicola) and have found that divergence within the vole L1 population is quite different from that in mice, in that there is no abundant subfamily of homologous elements. Individual L1 elements from voles are very divergent from one another and belong to a clade that began a period of elevated duplicative transposition approximately 13 Mya. Sequence analyses of portions of these divergent L1 elements (approximately 250 bp each) gave no evidence for concerted evolution having acted on the vole L1 elements since the split of the two vole lineages approximately 3.5 Mya; that is, the observed interspecific divergence (6.7%-24.7%) is not larger than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses showed no clustering into Arvicola and Microtus clades.   相似文献   
49.
Succession of bacterivorous protists on laboratory-made marine snow   总被引:1,自引:0,他引:1  
Colonization and succession over time by bacterivorous protistson laboratory-made marine snow were analysed in five assaysduring 1994. Marine snow was made hom natural seawater usingrolling tanks. In all experiments, the macroaggregates werestable in size and consistency after the fourth day, and thecolonization and succession processes were similar. Newly formedmacre aggregates became colonized by heterotrophic nanoflagellateson the fourth day, mmt of them kinete plastids (Bodo designisand Rhynchomonns nasuta) and bicosoecids (Pseudobodo tremulansand Bicosoeca sp.). Sarcodines and ciliates appeared 1 day later.Among the former, the most abundant genus was Vannella sp.,while scuticociliates (Uronema marinum) and hypotrichs (Euplotesvannus and Aspidisca steini) were the most abundant ciliates.Most of the species observed in the study were more common tobenthic habitats than to pelagic ones. The planktonic existenceof the genera Bodo, Rhynchomonas, Bicosoeca, Euplotes and Aspidiscadepends on the presence of surfaces because they are poor swimmersor immotile, and Pseudobodo and Vannella need attachment forfeeding. The only pelagic protist observed was Uronema, probablybecause its opportunistic behaviour leads it to exploit enrichedenvironments such as marine snow. Flagellate and ciliate abundancesin laboratory-made macroaggregates were much higher than insurrounding water, which indicates that marine snow representsan enhanced habitat for protist growth.  相似文献   
50.
Gypsy is an infectious endogenous retrovirus of Drosophila melanogaster. The gypsy proviruses replicate very efficiently in the genome of the progeny of females homozygous for permissive alleles of the flamenco gene. This replicative transposition is correlated with derepression of gypsy expression, specifically in the somatic cells of the ovaries of the permissive mothers. The determinism of this amplification was studied further by making chimeric mothers containing different permissive/restrictive and somatic/germinal lineages. We show here that the derepression of active proviruses in the permissive soma is necessary and sufficient to induce proviral insertions in the progeny, even if the F1 flies derive from restrictive germ cells devoid of active proviruses. Therefore, gypsy endogenous multiplication results from the transfer of some gypsy-encoded genetic material from the soma towards the germen of the mother and its subsequent insertion into the chromosomes of the progeny. This transfer, however, is not likely to result from retroviral infection of the germline. Indeed, we also show here that the insertion of a tagged gypsy element, mutant for the env gene, occurs at high frequency, independently of the production of gypsy Env proteins by any transcomplementing helper. The possible role of the env gene for horizontal transfer to new hosts is discussed.  相似文献   
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