Pattern analysis of stem cell differentiation during <Emphasis Type="Italic">in vitro Arabidopsis</Emphasis> organogenesis

Plant somatic cells have the capability to switch their cell fates from differentiated to undifferentiated status under proper culture conditions, which is designated as totipotency. As a result, plant cells can easily regenerate new tissues or organs from a wide variety of explants. However, the mechanism by which plant cells have such remarkable regeneration ability is still largely unknown. In this study, we used a set of meristem-specific marker genes to analyze the patterns of stem cell differentiation in the processes of somatic embryogenesis as well as shoot or root organogenesis in vitro. Our studies furnish preliminary and important information on the patterns of the de novo stem cell differentiation during various types of in vitro organogenesis.     

Microplastics in soil-plant system: effects of nano/microplastics on plant photosynthesis,rhizosphere microbes and soil properties in soil with different residues

Plant and Soil - To investigate the effects of polystyrene microplastics (PS-beads) on the soil properties, photosynthesis of Flowering Chinese cabbage, the rhizosphere microbial community and...     

Revealing Invisible Water: Moisture Recycling as an Ecosystem Service

An ecosystem service is a benefit derived by humanity that can be traced back to an ecological process. Although ecosystem services related to surface water have been thoroughly described, the relationship between atmospheric water and ecosystem services has been mostly neglected, and perhaps misunderstood. Recent advances in land-atmosphere modeling have revealed the importance of terrestrial ecosystems for moisture recycling. In this paper, we analyze the extent to which vegetation sustains the supply of atmospheric moisture and precipitation for downwind beneficiaries, globally. We simulate land-surface evaporation with a global hydrology model and track changes to moisture recycling using an atmospheric moisture budget model, and we define vegetation-regulated moisture recycling as the difference in moisture recycling between current vegetation and a hypothetical desert world. Our results show that nearly a fifth of annual average precipitation falling on land is from vegetation-regulated moisture recycling, but the global variability is large, with many places receiving nearly half their precipitation from this ecosystem service. The largest potential impacts for changes to this ecosystem service are land-use changes across temperate regions in North America and Russia. Likewise, in semi-arid regions reliant on rainfed agricultural production, land-use change that even modestly reduces evaporation and subsequent precipitation, could significantly affect human well-being. We also present a regional case study in the Mato Grosso region of Brazil, where we identify the specific moisture recycling ecosystem services associated with the vegetation in Mato Grosso. We find that Mato Grosso vegetation regulates some internal precipitation, with a diffuse region of benefit downwind, primarily to the south and east, including the La Plata River basin and the megacities of Sao Paulo and Rio de Janeiro. We synthesize our global and regional results into a generalized framework for describing moisture recycling as an ecosystem service. We conclude that future work ought to disentangle whether and how this vegetation-regulated moisture recycling interacts with other ecosystem services, so that trade-offs can be assessed in a comprehensive and sustainable manner.     

Ammonium photo-production by heterocytous cyanobacteria: potentials and constraints

Over the last decades, production of microalgae and cyanobacteria has been developed for several applications, including novel foods, cosmetic ingredients and more recently biofuel. The sustainability of these promising developments can be hindered by some constraints, such as water and nutrient footprints. This review surveys data on N₂-fixing cyanobacteria for biomass production and ways to induce and improve the excretion of ammonium within cultures under aerobic conditions. The nitrogenase complex is oxygen sensitive. Nevertheless, nitrogen fixation occurs under oxic conditions due to cyanobacteria-specific characteristics. For instance, in some cyanobacteria, the vegetative cell differentiation in heterocyts provides a well-adapted anaerobic microenvironment for nitrogenase protection. Therefore, cell cultures of oxygenic cyanobacteria have been grown in laboratory and pilot photobioreactors (Dasgupta et al., 2010; Fontes et al., 1987; Moreno et al., 2003; Nayak & Das, 2013). Biomass production under diazotrophic conditions has been shown to be controlled by environmental factors such as light intensity, temperature, aeration rate, and inorganic carbon concentration, also, more specifically, by the concentration of dissolved oxygen in the culture medium. Currently, there is little information regarding the production of extracellular ammonium by heterocytous cyanobacteria. This review compares the available data on maximum ammonium concentrations and analyses the specific rate production in cultures grown as free or immobilized filamentous cyanobacteria. Extracellular production of ammonium could be coupled, as suggested by recent research on non-diazotrophic cyanobacteria, to that of other high value metabolites. There is little information available regarding the possibility for using diazotrophic cyanobacteria as cellular factories may be in regard of the constraints due to nitrogen fixation.     

P物质在家兔延髓腹侧面加压区的升压作用及其机制探讨

在乌拉坦麻醉，三碘季铵酚制动，人工呼吸的家兔上观察到，延髓腹侧面加压区给予Ｐ物质使血压呈剂量依赖性升高，但对心率无明显影响。ＶＳＭｐ给予ＳＰ受体阻断使ＢＰ明显降低并可阻断ＳＰ升压效应，ＶＳＭｐ给予酚妥拉明或哌唑嗪预处理使ＳＰ升压效应减弱或消失，而给予育亨宾或心得安对ＳＰ升压效应无明显影响。ＶＳＭｐ给予ＳＰ可使肾交感神经放电显著增加，并伴有ＢＰ显著升高；ＶＳＭｐ给予ＤＳＰ使ＲＳＮＤ和ＢＰ明显降低并可     

Conformationally altered aortic myosin light chains

Aorta smooth myosin contains two types of light chain, LC20 and LC17, which fold together with the N-terminal region of each heavy chain to form the globular head region of myosin. We demonstrate an altered conformation of LC20 after its separation from heavy chain by high concentrations of urea, on the basis of the following evidende: 1) A polyclonal antibody against LC20 was not able to recognize this conformationally altered form; 2) Myosin reconstituted from heavy chains and urea-dissociated light chains exhibited extremely low ATPase activity. Circular dichroism unfolding profiles showed that light chains dissociated from heavy chains by SDS appeared to be more stable than those generated by urea dissociation.