The tea bag method provides a replicable and standardized method to study the effect of environmental variables on the decomposition of standard litter, which enables comparison of organic matter decomposition rates on a large scale. However, it remains uncertain whether tea bag decomposition in response to wetness is representative of that of local litters. We performed incubation experiments to examine whether the effect of soil water on tea bag decomposition becomes inhibitory at higher water contents, as is the case in local leaf litters. In addition, we performed field studies in a mixed forest and cedar plantation in Japan to compare two litter bag mesh sizes: 0.25-mm mesh, the size previously used by a major manufacturer of tea bags (Lipton), and nonwoven bags with mesh sizes finer than 0.25 mm, which are currently produced by Lipton. Both green tea and rooibos tea exhibited higher decomposition rates at higher water contents, but decomposition was inhibited at the highest water content; this was in contrast to our hypothesis based on a field observation but consistent with conceptual models of local litters. The nonwoven tea bags did not show lower decomposition rates, despite the finer mesh size. Rather, the nonwoven rooibos tea bags exhibited slightly higher decomposition rates than the 0.25-mm mesh bags in the cedar plantation, possibly due to a greater abundance of microorganisms that decompose litters in the nonwoven bags, due to the decrease in predation by mesofauna. Our findings provide essential information for future studies of tea bag decomposition.

No abstract

KaiC protein is the pivotal component of the circadian clock in cyanobacteria. While KaiC family proteins are well-conserved throughout divergent phylogenetic lineages, studies of the physiological roles of KaiC proteins from other microorganisms have been limited. We examined the role of the KaiC proteins, KaiC1 and KaiC2, in the methanol-utilizing bacterium Methylobacterium extorquens AM1. Wild-type M. extorquens AM1 cells exhibited temperature-dependent UV resistance (TDR) under permissive growth temperatures (24 °C -32 °C). Both the phosphorylation of KaiC2 and the intracellular levels of KaiC1 were temperature-dependent, and the TDR phenotype was positively regulated by KaiC1 and negatively regulated by KaiC2. Taken together with biochemical and functional analogies to the KaiC protein of cyanobacteria, our present results suggest that KaiC family proteins function to integrate environmental cues, that is, temperature and UV light, and output appropriate cellular responses to allow cells to adapt to changing environmental conditions.© 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

The tea bag method was developed to provide uniform litter bags that enable comparison of organic matter decomposition rates on a large scale. However, it remains uncertain whether tea bag decomposition in response to wetness is representative of that of natural litters. We performed incubation experiments to examine whether the effect of soil water on tea bag decomposition becomes inhibitory at higher water contents, as was demonstrated in natural leaf litters. In addition, we performed field studies in a mixed forest and cedar plantation in Japan to compare two litter bag mesh sizes: 0.25-mm mesh, the size previously used by a major manufacturer of tea bags (Lipton), and nonwoven bags with mesh sizes finer than 0.25 mm, which are currently produced by Lipton. Both green tea and rooibos tea exhibited higher decomposition rates at higher water contents, but decomposition was inhibited at the highest water content, consistent with conceptual models of natural litters. The nonwoven tea bags did not show lower decomposition rates, despite the finer mesh size. Rather, the nonwoven rooibos tea bags exhibited slightly higher decomposition rates than the 0.25-mm mesh bags in the cedar plantation, possibly due to a greater abundance of microorganisms that decompose litters in the nonwoven bags, due to the decrease in predation by mesofauna. Our findings provide essential information for future studies of tea bag decomposition.