منابع مشابه
Understanding the glacial methane cycle
Atmospheric methane (CH4) varied with climate during the Quaternary, rising from a concentration of 375 p.p.b.v. during the last glacial maximum (LGM) 21,000 years ago, to 680 p.p.b.v. at the beginning of the industrial revolution. However, the causes of this increase remain unclear; proposed hypotheses rely on fluctuations in either the magnitude of CH4 sources or CH4 atmospheric lifetime, or ...
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The AMPK (AMP-activated protein kinase) cascade plays a key role in regulating energy metabolism. Conditions which cause a decrease in the ATP/AMP ratio lead to activation of AMPK. Once activated, AMPK initiates a series of responses that act to restore the energy balance of the cell. In skeletal muscle, activation of AMPK increases both glucose uptake and fatty acid oxidation, raising the poss...
متن کاملThe methane cycle in ferruginous Lake Matano.
In Lake Matano, Indonesia, the world's largest known ferruginous basin, more than 50% of authigenic organic matter is degraded through methanogenesis, despite high abundances of Fe (hydr)oxides in the lake sediments. Biogenic CH₄ accumulates to high concentrations (up to 1.4 mmol L⁻¹) in the anoxic bottom waters, which contain a total of 7.4 × 10⁵ tons of CH₄. Profiles of dissolved inorganic ca...
متن کاملThe Role of Natural Wetlands in the Global Methane Cycle
Methane (CH4) is the most important greenhouse gas after water vapor and carbon dioxide (CO2), and wetlands represent its largest natural source. But the high spatial and temporal variability of CH4 emissions from natural wetlands combined with patchy and incomplete information on global wetland distribution makes them especially difficult to quantify. CH4 from natural wetlands still has the la...
متن کاملTransient intermediates of the methane monooxygenase catalytic cycle.
Three new intermediates of the catalytic cycle of the soluble form of methane monooxygenase (MMO) isolated from Methylosinus trichosporium OB3b have been detected using transient kinetic techniques. MMO consists of hydroxylase (MMOH), reductase, and "B" (MMOB) components. MMOH contains an oxygen-bridged [Fe(III).Fe(III)] cluster that catalyzes O2 activation and insertion chemistry. At 4 degrees...
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ژورنال
عنوان ژورنال: Nature
سال: 2015
ISSN: 0028-0836,1476-4687
DOI: 10.1038/nature14633