Evaluation of an ischemic model in ischemia prone and general Mongolian gerbils by neurological symptom, injury,and sex difference

Background: In the previous study, we established an ischemia-prone gerbil population(IG), which was selectively bred to increase the incidence of unilateral carotid arterial occlusion(UCO)-induced ischemia in Mongolian gerbils. However, if the characteristics of ischemia model in IG are the same as those in general gerbils(GG), and if the neurological symptoms are associated with the neurological insults in IG is still unclear.Methods: In the present study, we evaluated the UCO model in IG by analyzing neurological symptoms, neurological injury in the hippocampal CA1 region and compared with GG.Results: The data showed that the ratios of neurological symptom scores ≥ 2 in the IG and GG groups were 65.0% vs 30.0%, respectively, and were significantly different(P <.01).The neuronal damage following a UCO ischemic insult in the IG group was more severe compared to the GG group. There was a high correlation between the neurological insults' scale and the neurological symptom score in the IG and GG groups(r =.979 and.943 in the IG and GG groups, respectively). In animals with mild neurological symptom scores(2 and 3), the neuronal insults were significantly different between female and male gerbils in both IG and GG.Conclusion: Our findings suggest that IG population would likely be more advantageous to establish an ischemic model.

Plant phenolics mediated bottom-up effects of elevated CO2 on Acyrthosiphon pisum and its parasitoid Aphidius avenae

Elevated concentrations of atmospheric CO2 can alter plant secondary metabolites,which play important roles in the interactions among plants,herbivorous insects and natural enemies.However,few studies have examined the cascading effects of host plant secondary metabolites on tri-trophic interactions under elevated CO2(eCO2).In this study,we determined the effects of eCO2 on the growth and foliar phenolics of Medicago truncatula and the cascading effects on two color genotypes oiAcyrthosiphon pisum(pink vs.green)and their parasitoid Aphidius avenae in the field open-top chambers.Our results showed that eCO2 increased photosynthetic rate,nodule number,yield and the total phenolic content of M.truncatula.eCO2 had contrasting effects on two genotypes of A.pisum;the green genotype demonstrated increased population abundance,fecundity,growth and feeding efficiency,while the pink genotype showed decreased fitness and these were closely associated with the foliar genstein content.Furthermore,eCO2 decreased the parasitic rate of A.avenae independent of aphid genotypes.eCO2 prolonged the emergence time and reduced the emergence rate and percentage of females when associated with the green genotype,but little difference,except for increased percentage of females,was observed in A.avenae under eCO2 when associated with the pink genotype,indicating that parasitoids can perceive and discriminate the qualities of aphid hosts.We concluded that eCO2 altered plant phenolics and thus the performance of aphids and parasitoids.Our results indicate that plant phenolics vary by different abiotic and biotic stimuli and could potentially deliver the cascading effects of eCO2 to the higher trophic levels.Our results also suggest that the green genotype is expected to perform better in future eCO2 because of decreased plant resistance after its infestation and decreased parasitic rate.