Substrate scent-induced disproportionate seed dispersal by rodents.

Conspecific adults impose strong negative density-dependent effects on seed survival nearby parent trees, however, the underlying mechanisms are diversified and remain unclear. In this study, we presented consistent evidence that parent-scented forest floor masked seed odor, reduced cache recovery rate by scatter-hoarding animals, and then increased seed dispersal far away from mother trees. Our results showed that seed odors of Korean pine Pinus koraiensis match well with the volatile profile of their forest floor. Moreover, scatter-hoarding animals selectively transported P. koraiensis seeds toward the areas where seed odor was more contrasting against the background substrate, possibly due to the fact that accumulation of conspecific volatile compounds in caches hindered seed detection by scatter-hoarding animals. Our study provides insight into the role of leaf litter in directing seed dispersal process, representing a novel mechanism by which P. koraiensis increases selection for seed dispersal far away from the parent tree.

miR-142-5P regulates triglyceride by targeting CTNNB1 in goat mammary epithelial cells.

MicroRNAs (miRNAs) regulate genes through post-transcriptional regulation by targeting the 3'-UTR of mRNA to downregulate gene expression. Several reports have indicated that miRNA regulation can affect many physiological processes, including immune function, apoptosis, cell proliferation and differentiation, and milk fat metabolism. In this study, miR-142-5P promoted milk fat metabolism, and inhibition of miR-142-5P suppressed milk fat metabolism both in vivo and in vitro. The luciferase and Western blot assays indicated that catenin beta-1 (CTNNB1) is a potential target for miR-142-5P. In addition, CTNNB1 inhibited milk fat metabolism. In summary, miR-142-5P may promote milk fat metabolism by inhibiting CTNNB1 expression.

Study on Zn relative concentration and state in sheep duodenum by XAFS.

Synchrotron-based X-ray absorption fine structure (XAFS) spectroscopy is not widely used in animal science. The objective of this study was to employ the XAFS technique to determine changes in zinc absorption and concentrations in the sheep interstinal sac using different zinc sources. Forty-eight sheep were slaughtered and their duodena were dissected. The duodena were randomly assigned to six zinc sources (ZnO, ZnSO(4), ZnMet, ZnLys, ZnSO(4) + methionine, ZnSO(4) + lysine). Ten centimeters of duodenal sac midpiece was incubated for 40 min in vitro using the everted intestinal sac technique in culture medium containing zinc from different sources. The amount of zinc present was normalized to 4 mg. XAFS was used to analyze the relative concentration and oxidation state of zinc, and atomic absorption spectrometry (AAS) was used to verify zinc concentration. The results showed that, for increasing zinc concentrations, organic zinc was a better source than inorganic zinc. In addition, the zinc concentration achieved using ZnMet was higher than that for ZnO and ZnSO(4) (P < 0.05) as measured by atomic absorption spectroscopy. The results using XAFS were consistent with that of AAS. The states of organic zinc and inorganic zinc were identical after being incubated for 40 min. As observed in these experiments, organic zinc was more easily absorbed than inorganic zinc. Our data demonstrate that organic zinc was dissociated into ions and then absorbed as inorganic zinc. In our experiments, we are the first investigators to use XAFS spectroscopy to determine zinc absorption in the sheep duodenal wall. We observed reduced absorption of inorganic zinc in the presence of methionine or lysine. Taken together, we postulate that the optimal molar ratio of inorganic zinc and ligand requires further study.