Tropical wetlands: A missing link in the global carbon cycle?

Tropical wetlands are not included in Earth system models, despite being an important source of methane (CH) and contributing a large fraction of carbon dioxide (CO) emissions from land use, land use change, and forestry in the tropics. This review identifies a remarkable lack of data on the carbon balance and gas fluxes from undisturbed tropical wetlands, which limits the ability of global change models to make accurate predictions about future climate. We show that the available data on in situ carbon gas fluxes in undisturbed forested tropical wetlands indicate marked spatial and temporal variability in CO and CH emissions, with exceptionally large fluxes in Southeast Asia and the Neotropics.

Environmental controls of temporal and spatial variability in CO2 and CH4 fluxes in a neotropical peatland.

Tropical peatlands play an important role in the global storage and cycling of carbon (C) but information on carbon dioxide (CO2) and methane (CH4) fluxes from these systems is sparse, particularly in the Neotropics. We quantified short and long-term temporal and small scale spatial variation in CO2 and CH4 fluxes from three contrasting vegetation communities in a domed ombrotrophic peatland in Panama. There was significant variation in CO2 fluxes among vegetation communities in the order Campnosperma panamensis > Raphia taedigera > Cyperus.

Arabidopsis RecQsim, a plant-specific member of the RecQ helicase family, can suppress the MMS hypersensitivity of the yeast sgs1 mutant.

The Arabidopsis genome contains seven genes that belong to the RecQ family of ATP-dependent DNA helicases. RecQ members in Saccharomyces cerevisiae (SGS1) and man (WRN, BLM and RecQL4) are involved in DNA recombination, repair and genome stability maintenance, but little is known about the function of their plant counterparts. The Arabidopsis thaliana RecQsim gene is remarkably different from the other RecQ-like genes due to an insertion in its helicase domain.

Agrobacterium tumefaciens possesses a fourth flagelin gene located in a large gene cluster concerned with flagellar structure, assembly and motility.

The authors have identified a fourth flagellin gene in a 21850 bp region of the Agrobacterium tumefaciens C58C1 chromosome containing at least 20 genes concerned with flagellar structure, assembly and function. Three flagellin genes, flaA, flaB and flaC, orientated rightward, are positioned in a tandem array at the right end, with the fourth, substantially larger gene, flaD, in the opposite orientation, at the left end. Between these lie four apparent operons, two transcribed in each direction (motA, flhB leftward; flgF, flgB rightward) from a divergent position approx 7.