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21.
Gene expression and metabolite profiling of Populus euphratica growing in the Negev desert 总被引:4,自引:0,他引:4 下载免费PDF全文
Brosché M Vinocur B Alatalo ER Lamminmäki A Teichmann T Ottow EA Djilianov D Afif D Bogeat-Triboulot MB Altman A Polle A Dreyer E Rudd S Paulin L Auvinen P Kangasjärvi J 《Genome biology》2005,6(12):R101-17
Background
Plants growing in their natural habitat represent a valuable resource for elucidating mechanisms of acclimation to environmental constraints. Populus euphratica is a salt-tolerant tree species growing in saline semi-arid areas. To identify genes involved in abiotic stress responses under natural conditions we constructed several normalized and subtracted cDNA libraries from control, stress-exposed and desert-grown P. euphratica trees. In addition, we identified several metabolites in desert-grown P. euphratica trees.Results
About 14,000 expressed sequence tag (EST) sequences were obtained with a good representation of genes putatively involved in resistance and tolerance to salt and other abiotic stresses. A P. euphratica DNA microarray with a uni-gene set of ESTs representing approximately 6,340 different genes was constructed. The microarray was used to study gene expression in adult P. euphratica trees growing in the desert canyon of Ein Avdat in Israel. In parallel, 22 selected metabolites were profiled in the same trees.Conclusion
Of the obtained ESTs, 98% were found in the sequenced P. trichocarpa genome and 74% in other Populus EST collections. This implies that the P. euphratica genome does not contain different genes per se, but that regulation of gene expression might be different and that P. euphratica expresses a different set of genes that contribute to adaptation to saline growth conditions. Also, all of the five measured amino acids show increased levels in trees growing in the more saline soil. 相似文献22.
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24.
We studied the composition and density of the algae of the littoral epilithon and the taxa turnover in nine lentic water bodies at Hope Bay, Antarctic Peninsula, during summer 2002. At each site we measured the main physical and chemical variables, and took epilithic samples for the algal analysis. Two composed samples (one for qualitative and one for quantitative analysis) were taken randomly about 1 m away from the shore-line of each sampling site. The morphology of the algal mats could be included in the ‘moat and pond type’ in which Cyanobacteria are well represented. A total of 69 algal taxa were recorded in the whole study area. Chlorophyceae showed the highest taxa richness (33%), followed by Cyanobacteria (29%), Bacillariophyceae (26%), Chrysophyceae (10%), and Tribophyceae (2%). As a result of the redundancy analysis performed, we found that the number, composition, and density of taxa in the water bodies at Hope Bay were strongly influenced by nitrate and suspended solids concentrations and by the distance from the sea. The geographical trend in taxa turnover within Hope Bay was explained by elements from the combination of the metapopulation dynamics and the continuum theories, which are related to dispersal limitation and environmental heterogeneity, respectively. 相似文献
25.
During austral summer 1995/1996, 26 ultraoligotrophic to hypereutrophic ponds and lakes on Potter Peninsula (King George
Island, Antarctica) were characterized on the basis of abiotic factors and the phytoplankton community. The influence of vegetation
and animal presence in the catchment, morphometric variables of the water bodies and their proximity to the sea on composition
and abundance of phytoplankton was also considered. Results of a Principal Component Analysis show that the characteristics
of each catchment strongly influenced the abiotic parameter accounting for the obtained lake and pond ordination. In particular,
five groups of water bodies were clearly defined primarily based on nutrients and suspended solid concentrations, and to a
lesser extent on pH and conductivity. These groups could be classified into two assemblages distributed along a phytoplankton
biomass gradient, which is regulated by the light availability in one case and by nutrient concentrations in the other. Among
140 algal taxa registered, 3 were new records for Antarctica and 18 taxa were new records for Potter Peninsula. Bacillariophyceae
was the dominant class in terms of species number and density. Chlorophyta and Cyanobacteria were subdominant. The tychoplanktonic
habit was the best represented in almost all lakes.
Accepted: 3 June 2000 相似文献
26.
da Silva AC Brass KE da Silva Loreto E Vinocur ME Pozzobon R da Silva Azevedo M 《Genetics and molecular biology》2011,34(3):456-458
The aim was to detect the presence of polymorphisms at exons 1, 2, 3 and 4 of the Spi2 gene, and evaluate a possible association between them and recurrent airway obstruction (RAO) or inflammatory airway disease (IAD) in thoroughbred horses, through single-strand conformational-polymorphism (SSCP) screening. Although polymorphism was not detected in exons 1, 2 and 3, three alleles and six genotypes were identified in exon 4. The frequencies of allele A (0.6388) and genotype AA (0.3888) were higher in horses affected by RAO, although no association was found between polymorphism and horses with either RAO or IAD. 相似文献
27.
This paper presents the results of the floristic inventory of the freshwater Cyanophyceae found in plankton samples from nine lakes and ponds at Hope Bay (Antarctic Peninsula). Forty taxa were recorded, among which nine are new records for Antarctica. All the taxa are illustrated, and their distribution in Antarctica as well as the ecological characteristics of the sampling sites are given. The main morphological features and the geographic distribution are also given for the new records. 相似文献
28.
Floyd S Molesworth A Dube A Banda E Jahn A Mwafulirwa C Ngwira B Branson K Crampin AC Zaba B Glynn JR French N 《PloS one》2010,5(10):e13499
Background
Four studies from sub-Saharan Africa have found a substantial population-level effect of ART provision on adult mortality. It is important to see if the impact changes with time since the start of treatment scale-up, and as treatment moves to smaller clinics.Methods and Findings
During 2002-4 a demographic surveillance site (DSS) was established in Karonga district, northern Malawi. Information on births and deaths is collected monthly, with verbal autopsies conducted for all deaths; migrations are updated annually. We analysed mortality trends by comparing three time periods: pre-ART roll-out in the district (August 2002–June 2005), ART period 1 (July 2005–September 2006) when ART was available only in a town 70 km away, and ART period 2 (October 2006–September 2008), when ART was available at a clinic within the DSS area. HIV prevalence and ART uptake were estimated from a sero-survey conducted in 2007/2008. The all-cause mortality rate among 15–59 year olds was 10.2 per 1000 person-years in the pre-ART period (288 deaths/28285 person-years). It fell by 16% in ART period 1 and by 32% in ART period 2 (95% CI 18%–43%), compared with the pre-ART period. The AIDS mortality rate fell from 6.4 to 4.6 to 2.7 per 1000 person-years in the pre-ART period, period 1 and period 2 respectively (rate ratio for period 2 = 0.43, 95% CI 0.33–0.56). There was little change in non-AIDS mortality. Treatment coverage among individuals eligible to start ART was around 70% in 2008.Conclusions
ART can have a dramatic effect on mortality in a resource-constrained setting in Africa, at least in the early years of treatment provision. Our findings support the decentralised delivery of ART from peripheral health centres with unsophisticated facilities. Continued funding to maintain and further scale-up treatment provision will bring large benefits in terms of saving lives. 相似文献29.
Chandramohan D Shibuya K Setel P Cairncross S Lopez AD Murray CJ Zaba B Snow RW Binka F 《PLoS medicine》2008,5(2):e57
BACKGROUND TO THE DEBATE: Demographic surveillance--the process of monitoring births, deaths, causes of deaths, and migration in a population over time--is one of the cornerstones of public health research, particularly in investigating and tackling health disparities. An international network of demographic surveillance systems (DSS) now operates, mostly in sub-Saharan Africa and Asia. Thirty-eight DSS sites are coordinated by the International Network for the Continuous Demographic Evaluation of Populations and Their Health (INDEPTH). In this debate, Daniel Chandramohan and colleagues argue that DSS data in the INDEPTH database should be made available to all researchers worldwide, not just to those within the INDEPTH Network. Basia Zaba and colleagues argue that the major obstacles to DSS sites sharing data are technical, managerial, and financial rather than proprietorial concerns about analysis and publication. This debate is further discussed in this month's Editorial. 相似文献
30.
Hunter SC Isingo R Boerma JT Urassa M Mwaluko GM Zaba B 《Journal of biosocial science》2003,35(2):189-199
Recent studies in sub-Saharan Africa have shown that fertility is reduced among HIV-infected women compared with uninfected women. The size and pattern of this fertility reduction has important implications for antenatal clinic-based surveillance of the epidemic and also for estimates and projections of the demographic impact of the epidemic. This paper examines the association between HIV and fertility in Kisesa, a rural area in Tanzania, where HIV prevalence among adults is about 6% and gradually increasing. The analysis is based on data obtained through a demographic surveillance system in Kisesa during 1994-98 and two large sero-surveys of all residents in 1994-95 and 1996-97. The HIV-associated fertility reduction among women was investigated by estimating fertility rates by HIV status and prevalence rates by fertility status. A substantial reduction (29%) was observed in fertility among HIV-infected women compared with HIV-uninfected women. The fertility reduction was most pronounced during the terminal stages of infection, but no clear association with duration of infection was observed. Use of modern contraception was higher among HIV-infected women. However, both among contracepting and non-contracepting women, a substantial reduction in fertility was seen among HIV-infected women. 相似文献