Immp2l Mutation Induces Mitochondrial Membrane Depolarization and Complex Ⅲ Activity Suppression after Middle Cerebral Artery Occlusion in Mice

Objective We previously reported that mutations in inner mitochondrial membrane peptidase 2-like(Immp2l)increase infarct volume,enhance superoxide production,and suppress mitochondrial respiration after transient cerebral focal ischemia and reperfusion injury.The present study investigated the impact of heterozygous Immp2l mutation on mitochondria function after ischemia and reperfusion injury in mice.Methods Mice were subjected to middle cerebral artery occlusion for 1 h followed by 0,1,5,and 24 h of reperfusion.The effects of Immp2l^(+/−)on mitochondrial membrane potential,mitochondrial respiratory complex III activity,caspase-3,and apoptosis-inducing factor(AIF)translocation were examined.Results Immp2l^(+/−)increased ischemic brain damage and the number of TUNEL-positive cells compared with wild-type mice.Immp2l^(+/−)led to mitochondrial damage,mitochondrial membrane potential depolarization,mitochondrial respiratory complex III activity suppression,caspase-3 activation,and AIF nuclear translocation.Conclusion The adverse impact of Immp2l^(+/−)on the brain after ischemia and reperfusion might be related to mitochondrial damage that involves depolarization of the mitochondrial membrane potential,inhibition of the mitochondrial respiratory complex III,and activation of mitochondria-mediated cell death pathways.These results suggest that patients with stroke carrying Immp2l^(+/−)might have worse and more severe infarcts,followed by a worse prognosis than those without Immp2l mutations.

Detection performance improvement of photon counting chirped amplitude modulation lidar with response probability correction

Geiger mode avalanche photodiode detector （Gm-APD） possesses the ultra-high sensitivity. Photon counting chirped amplitude modulation （PCCAM） light detection and ranging （lidar） uses the counting results of the returned signal detected by Gm-APD to mix with the reference signal, which makes PCCAM lidar capable of realizing the ultra-high sensitivity, and this is very important for detecting the remote and weak signal. However, Gm-APD is a nonlinear device, different from traditional linear detectors. Due to the nonlinear response of Gm-APD, the counting results of the returned signal detected by Gm-APD are different from those of both the original modulation signal and the reference signal. This will affect the mixing effect and thus degrade the detection performance of PCCAM lidar. In this paper, we propose a response probability correction method. First, the response probability correction model is established on the basis of Gm-APD Poisson prob- ability response model. Then, the response probability correction model is used to adjust the original modulation signal that is used to drive laser, in order to make the counting results of the returned signal detected by Gm-APD better mix with the local reference signal in the same form. Through this method, the detection performance of PCCAM lidar is enhanced efficiently.

Super-sensitivity measurement of tiny Doppler frequency shifts based on parametric amplification and squeezed vacuum state

The precision measurement of Doppler frequency shifts is of great significance for improving the precision of speed measurement.This paper proposes a precision measurement scheme of tiny Doppler shifts by a parametric amplification process and squeezed vacuum state.This scheme takes a parametric amplification process and squeezed vacuum state into a detection system,so that the measurement precision of tiny Doppler shifts can exceed the Cram′er–Rao bound of coherent light.Simultaneously,a simulation study is carried out on the theoretical basis,and the following results are obtained:for the signal light of Gaussian mode,when the amplification factor g=1 and the squeezed factor r=0.5,the measurement error of Doppler frequency shifts is 14.4%of the Cramer–Rao bound of the coherent light in our system.At the same time,when the local light mode and squeezed vacuum state mode are optimized,the measurement precision of this scheme can be further improved by√(2n+1)/(n+1)times,where n is the mode-order of the signal light.

Diversity and functional analysis of Chinese bumblebee gut microbiota reveal the metabolic niche and antibiotic resistance variation of Gilliamella

Bumblebees play an important role in maintaining the balance of natural and agricultural ecosystems,and the characteristic gut microbiota of bumblebees exhibit significant mutualistic functions.China has the highest diversity of bumblebees;however,gut microbiota of Chinese bumblebees have mostly been investigated through cultureindependent studies.Here,we analyzed the gut communities of bumblebees from Sichuan,Yunnan,and Shaanxi provinces in China through 16S ribosomal RNA amplicon sequencing and bacterial isolation.It revealed that the bumblebees examined in this study harbored two gut enterotypes as previously reported:one is dominated by Gilliamella and Snodgrassella,and the other is distinguished by prevalent environmental species.The gut compositions obviously varied among different individual bees.We then isolated 325 bacterial strains and the comparative genomic analysis of Gillianiella strains revealed that galactose and pectin digestion pathways were conserved in strains from bumblebees,while genes for the utilization of arabinose,mannose,xylose,and rhamnose were mostly lost.Only two strains from the Chinese bumblebees possess the multidrug-resistant gene emrB,which is phylogenetically closely related to that from the symbionts of soil entomopathogenic nematode.In contrast,tetracycline-resistant genes were uniquely present in three strains from the USA.Our results illustrate the prevalence of strain-level variations in the metabolic potentials and the distributions of antibiotic-resistant genes in Chinese bumblebee gut bacteria.

Bumblebees with the socially transmitted microbiome:A novel model organism for gut microbiota research

Eusocial bumble and honey bees are important pollinators for global ecology and the agricultural economy.Although both the bumble and honey bees possess similar and host-restricted gut microbiota,they differ in aspects of morphology,autonomy,physiology,behavior,and life cycle.The social bee gut bacteria exhibit host specificity that is likely a result of long-term co-evolution.The unique life cycle of bumblebees is key for the acquisition and development of their gut microbiota,and affects the strain-level diversity of the core bacterial species.Studies on bumblebee gut bacteria show that they retain less functional capacity for carbohydrate metabolism compared with that of the honeybee.We discuss the potential roles of the bumblebee gut microbiota against pathogenic threats and the application of host-specific probiotics for bumblebees.Given the advantages of the bumblebee microbiome,including the simple structure and host specificity,and the ease of manipulating bumblebee colonies,we propose that bumblebees may provide a valuable system for understanding the general principles of host-microbe interactions,gut-brain axis,and vertical transmission.