Fundus photography,fundus fluorescein angiography,and optical coherence tomography of healthy cynomolgus monkey,New Zealand rabbit,Sprague Dawley rat,and BALB/c mouse retinas

Background:A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis.The choice of animal model is based on the measurability of specific parameters or structures,the applicability of clinical measurement technologies,and the similarity to human eye function.Studies of eye pathology usually compare optical parameters between a healthy and altered state,so accurate baseline assessments are critical,but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models.Methods:Three cynomolgus monkeys,six New Zealand rabbits,ten Sprague Dawley(SD)rats,and BALB/c mice were examined by fundus photography(FP),fundus fluorescein angiography(FFA),and optical coherence tomography(OCT).Results:Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP,FFA,and OCT.New Zealand rabbits have large eyeballs,but they have large optic disc and myelinated retinal nerve fibers in their retinas,and the growth pattern of retinal vessels were also different to the human retinas.Unlike monkeys and rabbits,the retinal vessels of SD rats and BALB/c mice were widely distributed and clear.The OCT performance of them were similar with human beings except the macular.Conclusions:Monkey is a good model to study changes in retinal structure associated with fundus disease,rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases,and rats and mice are good models for retinal vascular diseases.These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.

Brassinosteroids suppress ethylene-induced fruitlet abscission through LcBZR1/2-mediated transcriptional repression of LcACS1/4 and LcACO2/3 in litchi

Abscission in plants is tightly controlled by multiple phytohormones and the expression of various genes.However,whether the plant hormone brassinosteroids(BRs)are involved in this process is largely unknown.Here,we found that exogenous application of BRs reduced the ethylene-induced fruitlet abscission of litchi due to lower ethylene(ET)production and suppressed the expression of the ethylene biosynthetic genes LcACS1/4 and LcACO2/3 in the fruitlet abscission zone(FAZ).Two genes that encode the BR core signaling components brassinazole resistant(BZR)proteins,namely,LcBZR1 and LcBZR2,were characterized.LcBZR1/2 were localized to the nucleus and acted as transcription repressors.Interestingly,the LcBZR1/2 transcript levels were not changed during ET-induced fruitlet abscission,while their expression levels were significantly increased after BR application.Moreover,gel shift and transient expression assays indicated that LcBZR1/2 could suppress the transcription of LcACS1/4 and LcACO2/3 by specifically binding to their promoters.Importantly,ectopic expression of LcBZR1/2 in Arabidopsis significantly delayed floral organ abscission and suppressed ethylene biosynthesis.Collectively,our results suggest that BRs suppress ET-induced fruitlet abscission through LcBZR1/2-controlled expression of genes related to ethylene biosynthesis in litchi.In addition,similar results were observed in the Arabidopsis gain-of-function mutant bzr1-1D,which showed delayed floral organ abscission in parallel with lower expression of ACS/ACO genes and reduced ethylene production,suggesting that the mechanism of BZR-controlled organ abscission via regulation of ethylene biosynthesis might be conserved in Arabidopsis.

The transcriptional control of LcIDL1–LcHSL2 complex by LcARF5 integrates auxin and ethylene signaling for litchi fruitlet abscission

At the physiological level,the interplay between auxin and ethylene has long been recognized as crucial for the regulation of organ abscission in plants.However,the underlying molecular mechanisms remain unknown.Here,we identified transcription factors involved in indoleacetic acid(IAA)and ethylene(ET)signaling that directly regulate the expression of INFLORESCENCE DEFICIENT IN ABSCISSION(IDA)and its receptor HAESA(HAE),which are key components initiating abscission.Specifically,litchi IDAlike 1(LcIDL1)interacts with the receptor HAESA-like2(LcHSL2).Through in vitro and in vivo experiments,we determined that the auxin response factor LcARF5 directly binds and activates both LcIDL1 and LcHSL2.Furthermore,we found that the ETHYLENE INSENSITIVE 3-like transcription factor LcEIL3 directly binds and activates LcIDL1.The expression of IDA and HSL2 homologs was enhanced in Lc ARF5and Lc EIL3 transgenic Arabidopsis plants,but reduced in ein3 eil1 mutants.Consistently,the expressions of LcIDL1 and LcHSL2 were significantly decreased in Lc ARF5-and LcEIL3-silenced fruitlet abscission zones(FAZ),which correlated with a lower rate of fruitlet abscission.Depletion of auxin led to an increase in 1-aminocyclopropane-1-carboxylic acid(the precursor of ethylene)levels in the litchi FAZ,followed by abscission activation.Throughout this process,LcRF5 and LcEIL3 were induced in the FAZ.Collectively,our findings suggest that the molecular interactions between litchi AUXIN RESPONSE FACTOR 5(LcARF5)-LcIDL1/LcHSL2 and LcEIL3–LcIDL1 signaling modules play a role in regulating fruitlet abscission in litchi and provide a long-sought mechanistic explanation for how the interplay between auxin and ethylene is translated into the molecular events that initiate abscission.

PLSCR1 promotes apoptosis and clearance of retinal ganglion cells in glaucoma pathogenesis

Glaucoma is the leading cause of irreversible blindness worldwide.In the pathogen-esis of glaucoma,activated microglia can lead to retinal ganglion cells(RGCs)apoptosis and death,however,the molecular mechanisms remain largely unknown.We demonstrate that phospholipid scramblase 1(PLSCR1)is a key regulator promoting RGCs apoptosis and their clearance by microglia.As evidenced in retinal progenitor cells and RGCs of the acute ocular hypertension(AOH)mouse model,overexpressed PLSCR1 induced its translocation from the nucleus to the cytoplasm and cytomembrane,as well as elevated phosphatidylserine exposure and reactive oxygen species generation with subsequent RGCs apoptosis and death.These damages were effectively attenuated by PLSCR1 inhibition.In the AOH model,PLSCR1 led to an increase in M1 type microglia activation and retinal neuroinflammation.Upregulation of PLSCR1 resulted in strongly elevated phagocytosis of apoptotic RGCs by activated microglia.Taken together,our study provides important insights linking activated microglia to RGCs death in the glaucoma pathogenesis and other RGC-related neurodegenerative diseases.

Homogenous Sn-doped K(Ta,Nb)O_(3) single crystals and its high piezoelectric response

Perovskite K(Ta,Nb)O_(3)(KTN)single crystal has drawn great interests for its outstanding electro-optic performance and excellent piezoelectric response.However,growth of compositionally uniform KTN single crystals has always been a great challenge for the great segregation difference between Nb and Ta.In this work,we propose a thermal field optimization strategy to resolve this challenge.Homogenous Sn doped KTN(Sn:KTN)single crystal with significantly reduced composition gradient(0.003 mol/mm,1/4 e1/8 of other KTN system),minimal TC variation(13℃)and excellent piezoelectric and dielectric response(d_(33)=373 pC/N andε^(T)_(33)=5206)has been successfully achieved.We found that the functional properties of Sn:KTN were greatly affected by the near-room temperature tetragonal-cubic phase transition.From the intrinsic aspect,longitudinal lattice deformation becomes much easier,resulting in maximum piezoelectric(d^(*)_(33)),dielectric(ε^(T*)_(33)),elastic(s^(E*)_(33))and electromechanical coupling(k^(*)_(33))coefficients along polar direction[001]_(C).From the extrinsic aspect,both domain wall density and domain wall mobility are greatly improved for the reduced lattice distortion,which also contribute a lot to the functional properties.This work provides a simple and practical route for designing and growing high quality crystals,and more importantly,reveals the fundamental mechanism of the phase transitions/boundaries on the functional properties.

Enhanced electrical performance in CaBi_(4)Ti_(4)O_(15)ceramics through synergistic chemical doping and texture engineering

High-temperature piezoelectric materials with excellent piezoelectricity,low dielectric loss and large resistivity are highly desired for many industrial sectors such as aerospace,aircraft and nuclear power.Here a synergistic design strategy combining microstructural texture and chemical doping is employed to optimize CaBi 4Ti 4O15(CBT)ceramics with bismuth layer structure.High textured microstructure with an orientation factor of 80%e82%has been successfully achieved by the spark plasma sintering tech-nique.Furthermore,by doping MnO_(2),both advantages of hard doping and sintering aids are used to obtain the excellent electrical performance of d_(33)=27.3 pC/N,tandδ-0.1%,Q_(31)~2,307 and electrical re-sistivityρ~6.5×10^(10)Ω·cm.Up to 600℃,the 0.2%(in mass)Mn doped CBT ceramics still exhibit high performance of d_(33)=26.4 pC/N,r~1.5×10^(6)Ω·cm and tandδ~15.8%,keeping at an applicable level,thus the upper-temperature limit for practical application of the CBT ceramics is greatly increased.This work paves a new way for developing and fabricating excellent high-temperature piezoelectric materials.