排序方式: 共有3条查询结果,搜索用时 0 毫秒
1
1.
Plant-mediated methane emission from an Indian mangrove 总被引:3,自引:0,他引:3
Ramachandran Purvaja Ramachandran Ramesh Peter Frenzel† 《Global Change Biology》2004,10(11):1825-1834
Mangroves have been considered for a long time to be a minor methane source, but recent reports have shown that polluted mangroves may emit substantial amounts of methane. In an unpolluted Indian mangrove, we measured annual methane emission rates of 10 g CH4 yr?1 from the stands of Avicennia marina. This rate is of the same order of magnitude as rates from Northern wetlands. Methane emission from a freshwater‐influenced area was higher, but was lower from a stunted mangrove growing on a hypersaline soil. Methane emission was mediated by the pneumatophores of Avicennia. This was consistent with the methane concentration in the aerenchyma, which decreased on average from 350 ppmv in the cable roots to 10 ppmv in the emergent part of the pneumatophores. However, the number of pneumatophores varied seasonally. The minimum number occurred during the monsoon season, which reduced methane emissions largely. Ebullition from unvegetated areas may also be important, at least during monsoon season when measured bubble fluxes were occasionally about five times as high as pneumatophore‐mediated emissions. 相似文献
2.
Gopi M. Joyson Joe Jeevamani J. Goutham S. Simon Nina Tabitha Deepak Samuel V. Abhilash K. R. Robin R. S. Hariharan G. Muruganandam R. Krishnan P. Purvaja R. Ramesh R. 《Wetlands Ecology and Management》2021,29(5):653-668
Wetlands Ecology and Management - Coral reefs of Lakshadweep perform a range of vital ecosystem functions and sustain the livelihoods of island communities. Coral reefs provide ecosystem services... 相似文献
3.
BS Chia F Lanzas D Rifat A Herrera EY Kim C Sailer E Torres-Chavolla P Narayanaswamy V Einarsson J Bravo JM Pascale TR Ioerger JC Sacchettini PC Karakousis 《PloS one》2012,7(7):e40456
The frequency of individual genetic mutations conferring drug resistance (DR) to Mycobacterium tuberculosis has not been studied previously in Central America, the place of origin of many immigrants to the United States. The current gold standard for detecting multidrug-resistant tuberculosis (MDR-TB) is phenotypic drug susceptibility testing (DST), which is resource-intensive and slow, leading to increased MDR-TB transmission in the community. We evaluated multiplex allele-specific polymerase chain reaction (MAS-PCR) as a rapid molecular tool to detect MDR-TB in Panama. Based on DST, 67 MDR-TB and 31 drug-sensitive clinical isolates were identified and cultured from an archived collection. Primers were designed to target five mutation hotspots that confer resistance to the first-line drugs isoniazid and rifampin, and MAS-PCR was performed. Whole-genome sequencing confirmed DR mutations identified by MAS-PCR, and provided frequencies of genetic mutations. DNA sequencing revealed 70.1% of MDR strains to have point mutations at codon 315 of the katG gene, 19.4% within mabA-inhA promoter, and 98.5% at three hotspots within rpoB. MAS-PCR detected each of these mutations, yielding 82.8% sensitivity and 100% specificity for isoniazid resistance, and 98.4% sensitivity and 100% specificity for rifampin resistance relative to DST. The frequency of individual DR mutations among MDR strains in Panama parallels that of other TB-endemic countries. The performance of MAS-PCR suggests that it may be a relatively inexpensive and technically feasible method for rapid detection of MDR-TB in developing countries. 相似文献
1