Low interannual precipitation has a greater negative effect than seedling herbivory on the population dynamics of a short‐lived shrub,Schiedea obovata

Climate projections forecast more extreme interannual climate variability over time, with an increase in the severity and duration of extreme drought and rainfall events. Based on bioclimatic envelope models, it is projected that changing precipitation patterns will drastically alter the spatial distributions and density of plants and be a primary driver of biodiversity loss. However, many other underlying mechanisms can impact plant vital rates (i.e., survival, growth, and reproduction) and population dynamics. In this study, we developed a size‐dependent integral projection model (IPM) to evaluate how interannual precipitation and mollusk herbivory influence the dynamics of a Hawaii endemic short‐lived shrub, Schiedea obovata (Caryophyllaceae). Assessing how wet season precipitation effects population dynamics it critical, as it is the timeframe when most of the foliar growth occurs, plants flower and fruit, and seedlings establish. Temporal variation in wet season precipitation had a greater effect than mollusk herbivory on S. obovata population growth rate , and the impact of interannual precipitation on vital rates shifted across plant ontogeny. Furthermore, wet season precipitation influenced multiple vital rates in contrasting ways and the effect of precipitation on the survival of larger vegetative and reproductively mature individuals contributed the most to variation in the population growth rate. Among all combination of wet season precipitation and herbivory intensities, the only scenario that led to a growing population was when high wet precipitation was associated with low herbivory. Our study highlights the importance of evaluating how abiotic factors and plant–consumer interactions influence an organism across its life cycle to fully understand the underpinning mechanisms that structure its spatial and temporal distribution and abundance. Our results also illustrate that for short‐lived species, like S. obovata, seedling herbivory can have less of an effect on the dynamics of plant populations than decreased interannual precipitation.     

MiR‐16, as a potential NF‐κB‐related miRNA,exerts anti‐inflammatory effects on LPS‐induced myocarditis via mediating CD40 expression: A preliminary study

The purpose of this study was to investigate the biological effect of miR‐16 on myocarditis and the underlying molecular mechanism. H9c2 cells were treated with 10 µg/mL lipopolysaccharide (LPS) for 12 hours to form a myocarditis injury model. We observed that LPS treatment distinctly decreased the level of miR‐16 in H9c2 cells. Upregulation of miR‐16 increased cell proliferation and reduced cell apoptosis. Then, CD40 was predicted and verified as a target gene of miR‐16 by TargetScan and luciferase reporter assay, respectively. Furthermore, the messenger RNA and protein expression of CD40 are negatively regulated by miR‐16. The relative expression of inflammatory factors was dramatically decreased by the miR‐16 mimic. Cells cotransfected with miR‐16 mimic and si‐CD40 could significantly abolish the injury of cardiomyocytes caused by myocarditis. Our study illustrated that the upregulation of miR‐16 has a protective effect on LPS‐damaged H9c2 cells, which may be achieved by regulating CD40 and the nuclear factor kappa B pathway.     

Kinetic studies of the effect of a 17‐nucleotide difference in the 0.3‐kb region containing the R‐U5‐5′ leader sequence of Friend murine leukemia virus on viral gene expression

In addition to the env gene, a 0.3‐kb fragment containing the R‐U5‐5′ leader sequence is essential for the induction of spongiform neurodegeneration by Friend murine leukemia virus (Fr‐MLV) clone A8 and it also influences expression of the Env protein. Kinetic studies were carried out using two recombinant viruses, R7f, carrying the A8 0.3‐kb fragment, and Rec5, carrying the 0.3‐kb fragment of the non‐neuropathogenic Fr‐MLV clone 57. These analyses suggested that the 0.3‐kb fragment influenced the expression level of the Env protein by regulating the amount of spliced env‐mRNA rather than the amount of total viral mRNA or viral production.