Susceptibility and tissue specificity of Spodoptera frugiperda to Junonia coenia densovirus

The fall armyworm,Spodoptera frugiperda,which destroys many economic crops such as rice and maize,has recently invaded China.Insect viruses as biological control agents play important roles in killing pests.One potential viral insecticide is the environmentally highly infective and virulent densovirus.We successfully rescued Junonia coenia densovirus(JcDV)using its infectious clone in different insect cell lines and larvae of three insect species.Results showed that the lysate of cultured insect cells transfected by the JcDV infectious clone killed the 2 nd instar S.frugiperda.The LD50 of homogenate from JcDV-infected Spodoptera litura to the 2 nd instar S.frugiperda(1.76×10^(8)viral genome copies per larva during 10 d post infection)was higher than that of the 2 nd instar S.litura(7.39×10^(7)Jc DV genome copies)or Helicoverpa armigera larvae(9.71×10^(7)JcDV genome copies).The LT50 of the S.litura homogenate(2.60×10^(9)viral genome copies each larva)to the 2 nd instar S.frugiperda was 6.96 d,longer than that of the S.litura(6.18 d)or the 2 nd instar H.armigera(5.94 d).JcDV could infect the fat body of H.armigera,but not S.frugiperda or S.litura.Although JcDV can infect all three lepidopteran species,their susceptibility to the virus differs.JcDV has great potential as a biological control agent against pests such as S.frugiperda.

MiR-20 Regulates Myocardiac Ischemia by Targeting KATP Subunit Kir6.1

This study aimed to examine the functional role of micro RNA-20（miR-20） and its potential target, Kir6.1, in ischemic myocardiocytes. The expression of miR-20 was detected by real-time PCR. Myocardiocytes were stained with terminal deoxynucleotidyl transferase d UTP nick end labeling（TUNEL） reagent for apoptosis evaluation. Western blotting was used to detect the Kir6.1 protein in ischemic myocardiocytes transfected with miR-20 mimics or inhibitors. Luciferase reporter gene assay was performed to confirm the targeting effect of miR-20 on KCNJ8. The results showed that miR-20 was remarkably down-regulated, while the KATP subunit Kir6.1 was significantly up-regulated, during myocardial ischemia. The miR-20 overexpression promoted the apoptosis of ischemic myocardiocytes, but showed no such effect on normal cells. Under ischemic condition, myocardiocytes transfected with miR-20 mimics expressed less Kir6.1. On the contrary, inhibiting miR-20 increased the expression of Kir6.1 in the cells. Co-transfection of miR-20 mimics with the KCNJ8 3＇-UTR plasmid into HEK293 cells consistently produced less luciferase activity than transfection of the plasmid alone. It was concluded that miR-20 may regulate myocardiac ischemia by targeting KATP subunit Kir6.1 to accelerate the cell apoptosis. Therefore miR-20 may serve as a therapeutic target for myocardial ischemic disease.

Improvement and Application of Acute Blood Stasis Rat Model Aligned with the 3Rs (Reduction, Refinement and Replacement) of Humane Animal Experimentation

Objective:To establish a novel cardiocentesis method for withdrawing venous blood from the right atrium,and to improve an acute blood stasis rat model using an ice bath and epinephrine hydrochloride(Epi)while considering the 3Rs(reduction,refinement,and replacement)of humane animal experimentation.Methods:An acute blood stasis model was established in male Sprague-Dawley rats by subcutaneous injection(s.c.)Epi(1.2mg/kg)administration at 0h,followed by a 5-min exposure to an ice-bath at 2h and s.c.Epi administration at 4h.Control rats received physiological saline.Rats were fasted overnight and treated with Angelicae Sinensis Lateralis Radix(ASLR)and Pheretima the following day.Venous blood was collected using our novel cardiocentesis method and used to test whole blood viscosity(WBV),prothrombin time(PT),activated partial thromboplastin time(APTT),and fibrinogen(FIB)8ntent.Results:The rats survived the novel cardiocentesis technique;WBV value returned to normal while hematological parameters such as hemoglobin level and red blood cell count were restored to>94%of the corresponding values in normal rats following a 14-day recovery.Epi(1.2 mg/kg,s.c.)combined with a 5-min exposure to the ice bath replicated the acute blood stasis rat model and was associated with the highest WBV value.In rats showing acute blood stasis,ASLR treatment[4g/(kg-d)for 8 days]decreased WBV by 9.98%,11.09%,9.34%,9.00%,7.66%,and 7.03%(P<0.05),while Pheretima treatment[2.6g/(kg?d),for 8 days]decreased WBV by 25.49%,25.94%,16.28%,17.76%,11.07%,and 7.89%(P<0.01)at shear rates of 1,3,10,30,100,and 180 s'1,respectively.Furthermore,Pheretima treatment increased APTT significantly(P<0.01).Conclusions:We presented a stable,reproducible,and improved acute blood stasis rat model,which could be applied to screen drugs for promoting blood circulation and eliminating blood stasis.

MiR319-targeted OsTCP21 and OsGAmyb regulate tillering and grain yield in rice

Multiple genes and microRNAs(miRNAs)improve grain yield by promoting tillering.MiR319s are known to regulate several aspects of plant development;however,whether miR319s are essential for tillering regulation remains unclear.Here,we report that miR319 is highly expressed in the basal part of rice plant at different development stages.The miR319 knockdown line Short Tandem Target Mimic 319(STTM319)showed higher tiller bud length in seedlings under low nitrogen(N)condition and higher tiller bud number under high N condition compared with the miR319a-overexpression line.Through targets prediction,we identified OsTCP21 and OsGAmyb as downstream targets of miR319.Moreover,OsTCP21 and OsGAmyb overexpression lines and STTM319 had increased tiller bud length and biomass,whereas both were decreased in OsTCP21 and OsGAmyb knockout lines and OE319a.These data suggest that miR319 regulates rice tiller bud development and tillering through targeting OsTCP21 and OsGAmyb.Notably,the tiller number and grain yield increased in STTM319 and overexpression lines of OsTCP21 and OsGAmyb but decreased in OE319a and knockout lines of OsTCP21 and OsGAmyb.Taken together,our findings indicate that miR319s negatively affect tiller number and grain yield by targeting OsTCP21 and OsGAmyb,revealing a novel function for miR319 in rice.