Grazing reduces plant sexual reproduction but increases asexual reproduction: A global meta-analysis.

Grazing affects grasslands worldwide. However, the global patterns and general mechanisms of how grazing affects plant reproductive traits are poorly understood, especially in the context of different climates and grazing duration. We conducted a meta-analysis of 114 independent grazing studies worldwide that measured plant reproductive traits in grasslands. The results showed that the number of tillers of plant increased under grazing. Grazing did not affect the number of reproductive branches of forbs, but significantly reduced the number of reproductive branches of grasses. Grazing increased the number of vegetative branches of all plants and reduced the proportion of reproductive branches. Grazing significantly reduced the number of flowers in forbs. Seed yield in the two plant functional groups was reduced compared with no-grazing. Under grazing, the sexual reproduction of grasses decreased much more substantially than that of forbs. This may be due to biomass allocation pattern of grasses under grazing (i.e., belowground versus aboveground). Under grazing, plants tended to adopt rapid, low-input asexual reproduction rather than long-term, high-risk sexual reproduction. This study represents the first large-scale evaluation of plant reproductive trait responses under grazing and demonstrates that grazing inhibits sexual reproduction and promotes asexual reproduction. The effect of grazing on plant sexual reproduction was influenced by grazing intensity, mean annual precipitation, and grazing duration. These results will assist in the development of sustainable grazing management strategies to improve the balance between human welfare and grassland ecosystem health.

Plant roots send metabolic signals to microbes in response to long-term overgrazing.

Overgrazing directly and indirectly affects soil microorganisms, which can have feedback effects on plant growth. Little is known about the root metabolites plants produce and whether they recruit beneficial microbes in response to overgrazing. Here, we used the dominant grassland species Leymus chinensis to explore correlations between root metabolites and the rhizosphere microbiome shaped by long-term overgrazing, which was determined by using LC-MS technology and high-throughput sequencing. In total, 839 metabolites were detected, with 41 significantly higher and 3 significantly lower in overgrazing versus grazing exclusion plots. The rhizosphere bacterial community was changed, but the fungal community was not altered. Moreover, 11 bacterial orders were found only in the overgrazed samples, and these showed close relationships to root metabolites and certain soil properties. Of these, Latescibacterales, B10-SB3A, and Nitrosococcales are known to be involved in growth promotion, C and N metabolism, respectively. In addition, root metabolites play an important role in mediating root-fungi interactions. The beneficial fungal orders Agaricales and Sordariales have a tread to be higher maybe due to root metabolites, mainly facilitate nutrient absorption and protect organic carbon in the soil, respectively. Our results indicate that grassland plants send metabolic signals to recruit key beneficial bacteria and stabilize fungal communities to alleviate grazing-induced stress in typical grassland ecosystems.

Generation and preliminary application of polyclonal antibodies against human Argonaute2 / 中国免疫学杂志

Objective:To generate rabbit polyclonal antibody against human Argonaute2 (Ago2) protein and to identify its functional characterization for determination of differential expression and cellular localization of Ago2 protein in various cell lines.Methods:DNAstar software was applied for searching the high antigenicity region of Ago2 gene sequence termed k-Ago2.Prokaryotic expressing plasmid was constructed and transformed to E.coli BL21 (DE3) to induce expression by IPTG.The fusion protein was injected into rabbits subcutaneously to produce polyclonal antibodies after purification by gel regaining.ELISA was operated to detect antibody titer.Western blot was used to identify the specificity and sensitivity of the antibodies and detect the differential expression of Ago2 protein in various cell lines.Meanwhile,immunofluorescence experiments were arranged to show cellular localization of Ago2 protein.Results:The prokaryotic expressing plasmid was constructed correctly.K-Ago2 protein was expressed and purified,and then rabbit polyclonal antibodies against Ago2 were generated after immunization with k-Ago2 protein.The titer detected by ELISA was 1∶19 000.Western blot results demonstrated the high specificity of the antibodies.Finally,we successfully observed the differential expression and cellular localization of Ago2 protein in various cell lines.Conclusion:The polyclonal antibody against Ago2 protein has been achieved successfully.It will be propitious for the intensive study of the RNAi mechanism and even profound clinical application.

Effects of inhibiting Kit signal pathway on proliferation and spontaneous rhythmic motility of interstitial cells in bladder of guinea pigs / 第三军医大学学报

Objective To investigate the role of Kit signal pathway in the proliferation and spontaneous rhythmic motility of interstitial cells(ICs)in the bladder of guinea pigs.Methods Fourteen Guinea pigs aged 45-60 days were administered with Imatinib intragastrically for 20 and 40 days.Three were fed on normal saline as control.The morph and number of ICs were observed by immunofluorescence,Kit protein expression was detected by Western blot and spontaneous rhythmic motility of bladder were investigated in in vitro organ bath.Results Quite a few ICs were observed in the bladder of controls.After administration of Imatinib,the amount of ICs and the expression of Kit protein decreased gradually,and the spontaneous rhythmic contraction weakened.Conclusion ICs might be the pacemaker of bladder in guinea pigs.Kit protein might play an important role in the survival and functional maintenance of ICs.