排序方式: 共有48条查询结果,搜索用时 31 毫秒
1.
Yakuba M. Bah Jusufu Paye Mohamed S. Bah Abdulai Conteh Victoria Redwood-Sawyerr Mustapha Sonnie Amy Veinoglou Joseph B. Koroma Mary H. Hodges Yaobi Zhang 《PLoS neglected tropical diseases》2020,14(12)
BackgroundLymphatic filariasis (LF) is targeted for elimination in Sierra Leone. Epidemiological coverage of mass drug administration (MDA) with ivermectin and albendazole had been reported >65% in all 12 districts annually. Eight districts qualified to implement transmission assessment survey (TAS) in 2013 but were deferred until 2017 due to the Ebola outbreak (2014–2016). In 2017, four districts qualified for conducting a repeat pre-TAS after completing three more rounds of MDA and the final two districts were also eligible to implement a pre-TAS.Methodology/Principal findingsFor TAS, eight districts were surveyed as four evaluation units (EU). A school-based survey was conducted in children aged 6–7 years from 30 clusters per EU. For pre-TAS, one sentinel and one spot check site per district (with 2 spot check sites in Bombali) were selected and 300–350 persons aged 5 years and above were selected. For both surveys, finger prick blood samples were tested using the Filariasis Test Strips (FTS).For TAS, 7,143 children aged 6–7 years were surveyed across four EUs, and positives were found in three EUs, all below the critical cut-off value for each EU. For the repeat pre-TAS/pre-TAS, 3,994 persons over five years of age were surveyed. The Western Area Urban had FTS prevalence of 0.7% in two sites and qualified for TAS, while other five districts had sites with antigenemia prevalence >2%: 9.1–25.9% in Bombali, 7.5–19.4% in Koinadugu, 6.1–2.9% in Kailahun, 1.3–2.3% in Kenema and 1.7% - 3.7% in Western Area Rural.Conclusions/SignificanceEight districts in Sierra Leone have successfully passed TAS1 and stopped MDA, with one more district qualified for conducting TAS1, a significant progress towards LF elimination. However, great challenges exist in eliminating LF from the whole country with repeated failure of pre-TAS in border districts. Effort needs to be intensified to achieve LF elimination. 相似文献
2.
Olympe Chazara Chi-Sheng Chang Nicolas Bruneau Khalid Benabdeljelil Jean-Claude Fotsa Boniface B. Kayang N’Goran E. Loukou Richard Osei-Amponsah Valentine Yapi-Gnaore Issaka A. K. Youssao Chih-Feng Chen Marie-Hélène Pinard-van der Laan Michèle Tixier-Boichard Bertrand Bed’Hom 《Immunogenetics》2013,65(6):447-459
The chicken major histocompatibility complex (MHC) is located on the microchromosome 16 and is described as the most variable region in the genome. The genes of the MHC play a central role in the immune system. Particularly, genes encoding proteins involved in the antigen presentation to T cells. Therefore, describing the genetic polymorphism of this region is crucial in understanding host–pathogen interactions. The tandem repeat LEI0258 is located within the core area of the B region of the chicken MHC (MHC-B region) and its genotypes correlate with serology. This marker was used to provide a picture of the worldwide diversity of the chicken MHC-B region and to categorize chicken MHC haplotypes. More than 1,600 animals from 80 different populations or lines of chickens from Africa, Asia, and Europe, including wild fowl species, were genotyped at the LEI0258 locus. Fifty novel alleles were described after sequencing. The resulting 79 alleles were classified into 12 clusters, based on the SNPs and indels found within the sequences flanking the repeats. Furthermore, hypotheses were formulated on the evolutionary dynamics of the region. This study constitutes the largest variability report for the chicken MHC and establishes a framework for future diversity or association studies. 相似文献
3.
Vlahakis NE Young BA Atakilit A Hawkridge AE Issaka RB Boudreau N Sheppard D 《The Journal of biological chemistry》2007,282(20):15187-15196
Vascular endothelial growth factor A (VEGF-A) is a potent inducer of angiogenesis. We now show that VEGF-A-induced adhesion and migration of human endothelial cells are dependent on the integrin alpha9beta1 and that VEGF-A is a direct ligand for this integrin. Adhesion and migration of these cells on the 165 and 121 isoforms of VEGF-A depend on cooperative input from alpha9beta1 and the cognate receptor for VEGF-A, VEGF receptor 2 (VEGF-R2). Unlike alpha3beta1or alphavbeta3 integrins, alpha9beta1 was also found to bind the 121 isoform of VEGF-A. This interaction appears to be biologically significant, because alpha9beta1-blocking antibody dramatically and specifically inhibited angiogenesis induced by VEGF-A165 or -121. Together with our previous findings that alpha9beta1 directly binds to VEGF-C and -D and contributes to lymphangiogenesis, these results identify the integrin alpha9beta1 as a potential pharmacotherapeutic target for inhibition of pathogenic angiogenesis and lymphangiogenesis. 相似文献
4.
5.
Characterization of multiple multivesicular body sorting determinants within Sna3: a role for the ubiquitin ligase Rsp5
下载免费PDF全文
![点击此处可从《Molecular biology of the cell》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Oestreich AJ Aboian M Lee J Azmi I Payne J Issaka R Davies BA Katzmann DJ 《Molecular biology of the cell》2007,18(2):707-720
A subset of proteins that transit the endosomal system are directed into the intralumenal vesicles of multivesicular bodies (MVBs). MVB formation is critical for a variety of cellular functions including receptor down-regulation, viral budding, antigen presentation, and the generation of lysosome-related organelles. Entry of transmembrane proteins into the intralumenal vesicles of a MVB is a highly regulated process that is positively modulated by covalent modification of cargoes with ubiquitin. To identify additional MVB sorting signals, we examined the previously described ubiquitination-independent MVB cargo Sna3. Although Sna3 ubiquitination is not essential, Sna3 MVB sorting is positively modulated by its ubiquitination. Examination of MVB sorting determinants within a form of Sna3 lacking all lysine residues identified two critical regions: an amino-terminal tyrosine-containing region and a carboxyl-terminal PPAY motif. This PPAY motif interacts with the WW domains of the ubiquitin ligase Rsp5, and mutations in either the WW or, surprisingly, the HECT domains of Rsp5 negatively impacted MVB targeting of lysine-minus Sna3. These data indicate that Rsp5 function is required for MVB targeting of Sna3 in a capacity beyond cargo ubiquitination. These results uncover a series of determinants impacting Sna3 MVB sorting, including unexpected roles for Rsp5. 相似文献
6.
Fargette D Pinel A Rakotomalala M Sangu E Traoré O Sérémé D Sorho F Issaka S Hébrard E Séré Y Kanyeka Z Konaté G 《Journal of virology》2008,82(7):3584-3589
The rate of evolution of an RNA plant virus has never been estimated using temporally spaced sequence data, by contrast to the information available on an increasing range of animal viruses. Accordingly, the evolution rate of Rice yellow mottle virus (RYMV) was calculated from sequences of the coat protein gene of isolates collected from rice over a 40-year period in different parts of Africa. The evolution rate of RYMV was estimated by pairwise distance linear regression on five phylogeographically defined groups comprising a total of 135 isolates. It was further assessed from 253 isolates collected all over Africa by Bayesian coalescent methods under strict and relaxed molecular clock models and under constant size and skyline population genetic models. Consistent estimates of the evolution rate between 4 x 10(-4) and 8 x 10(-4) nucleotides (nt)/site/year were obtained whatever method and model were applied. The synonymous evolution rate was between 8 x 10(-4) and 11 x 10(-4) nt/site/year. The overall and synonymous evolution rates of RYMV were within the range of the rates of 50 RNA animal viruses, below the average but above the distribution median. Experimentally, in host change studies, substitutions accumulated at an even higher rate. The results show that an RNA plant virus such as RYMV evolves as rapidly as most RNA animal viruses. Knowledge of the molecular clock of plant viruses provides methods for testing a wide range of biological hypotheses. 相似文献
7.
Thera MA Doumbo OK Coulibaly D Diallo DA Kone AK Guindo AB Traore K Dicko A Sagara I Sissoko MS Baby M Sissoko M Diarra I Niangaly A Dolo A Daou M Diawara SI Heppner DG Stewart VA Angov E Bergmann-Leitner ES Lanar DE Dutta S Soisson L Diggs CL Leach A Owusu A Dubois MC Cohen J Nixon JN Gregson A Takala SL Lyke KE Plowe CV 《PloS one》2008,3(1):e1465
Background
The objective was to evaluate the safety, reactogenicity and immunogenicity of the AMA-1-based blood-stage malaria vaccine FMP2.1/AS02A in adults exposed to seasonal malaria.Methodology/Principal Findings
A phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02A is a recombinant protein (FMP2.1) based on apical membrane antigen-1 (AMA-1) from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert). Sixty healthy, malaria-experienced adults aged 18–55 y were recruited into 2 cohorts and randomized to receive either a half dose or full dose of the malaria vaccine (FMP2.1 25 µg/AS02A 0.25 mL or FMP2.1 50 µg/AS02A 0.5 mL) or rabies vaccine given in 3 doses at 0, 1 and 2 mo, and were followed for 1 y. Solicited symptoms were assessed for 7 d and unsolicited symptoms for 30 d after each vaccination. Serious adverse events were assessed throughout the study. Titers of anti-AMA-1 antibodies were measured by ELISA and P. falciparum growth inhibition assays were performed on sera collected at pre- and post-vaccination time points. Transient local pain and swelling were common and more frequent in both malaria vaccine dosage groups than in the comparator group. Anti-AMA-1 antibodies increased significantly in both malaria vaccine groups, peaking at nearly 5-fold and more than 6-fold higher than baseline in the half-dose and full-dose groups, respectively.Conclusion/Significance
The FMP2.1/AS02A vaccine had a good safety profile, was well-tolerated, and was highly immunogenic in malaria-exposed adults. This malaria vaccine is being evaluated in Phase 1 and 2 trials in children at this site.Trial Registration
ClinicalTrials.gov NCT00308061相似文献8.
Zeyaur R. Khan Charles A. O. Midega Lester J. Wadhams John A. Pickett & Abdulai Mumuni 《Entomologia Experimentalis et Applicata》2007,124(2):201-211
We evaluated eight Napier grass [Pennisetum purpureum Schumach (Poaceae)] varieties, used in various parts of eastern Africa as fodder, for their potential role as trap plants in the management of the African stemborer, Busseola fusca Füller (Lepidoptera: Noctuidae) through a push–pull strategy. Oviposition preference, larval orientation, settling, arrest and dispersal, feeding, mortality and survival, and development were determined for each of these varieties under laboratory and screen house conditions. Two‐choice tests showed that only two of the varieties tested (cv. Bana and cv. Uganda Hairless) were preferentially chosen by gravid female moths for oviposition over a susceptible maize variety, cv. Western Hybrid 502. Larval preference was, however, highly variable. Larval feeding by first instars on the maize leaves was more intense and significantly more than on leaves of all the Napier grass varieties evaluated. Food consumed and amounts assimilated by the third instars over a 24‐h period were not different among larvae fed on stems of maize and those fed on stems of the various Napier grass varieties. Larval survival was significantly lower on all the Napier grass varieties (below 3%) than on maize (about 44%). Similarly, larval development was about 2–3 weeks longer on majority of the Napier grass varieties. It was concluded that cv. Bana had potential for use as a trap plant in the management of B. fusca because it was more preferred by the moths for oviposition, equally preferred as maize by the larvae for orientation, settling, and arrest, and allowed minimal survival of the larvae. It can thus be used with such ‘push’ plants as Desmodium spp. (Fabaceae) in a ‘push–pull’ strategy, but the effectiveness of such a strategy would strictly depend on proper establishment and management of these companion plants. 相似文献
9.
Although funds for livestock conservation are limited there is little known about the optimal allocation of conservation funds. A new algorithm was used to allocate Mio US$ 1, 2, 3, 5 or unlimited funds, discounted over 50 years, on 23 African cattle breeds conserved with four different possible conservation programs. Additionally, Mio US$ 1 was preferably allocated to breeds with special traits. The conceptional in situ conservation programs strongly involve breeders and give them part of the responsibility for the conservation of the breed. Therefore, the pure in situ conservation was more efficient than cryoconservation or combined in situ and cryoconservation. The average annual discounted conservation cost for a breed can be as low as US$ 1000 to US$ 4400 depending on the design of the conservation program and the economic situation of the country of conservation. The choice of the breeds and the optimal conservation program and the amount of money allocated to each breed depend on many factors such as the amount of funds available, the conservation potential of each breed, the effects of the conservation program as well as its cost. With Mio US$ 1, 64% of the present diversity could be maintained over 50 years, which is 13% more than would be maintained if no conservation measures were implemented. Special traits could be conserved with a rather small amount of the total funds. Diversity can not be conserved completely, not even with unlimited funds. A maximum of 92% of the present diversity could be conserved with Mio US$ 10, leaving 8% of the diversity to unpredictable happenings. The suggested algorithm proved to be useful for optimal allocation of conservation funds. It allocated the funds optimally among breeds by identifying the most suited conservation program for each breed, also accounting for differences in currency exchange rates between the different countries. 相似文献
10.