Molecular characterization and expression of sensory neuron membrane proteins in the parasitoid Microplitis mediator (Hymenoptera: Braconidae)

Sensory neuron membrane proteins(SNMPs),homologs of the human fatty acid transport protein CD36 family,are observed to play a significant role in chemoreception,especially in detecting sex pheromone in Drosophila and some lepidopteran species.In the current study,two full‐length SNMP transcripts,MmedSNMP1 and MmedSNMP2,were identified in the parasitoid Microplitis mediator(Hymenoptera:Braconidae).Quantitative real‐time polymerase chain reaction analysis showed that the expression of MmedSNMP1 was significantly higher in antennae than in other tissues of both sexes.In addition,the MmedSNMP1 transcript was increased dramatically in newly emerged adults and there were no significant differences between adults with or without mating and parasitic experiences.However,compared with MmedSNMP1,the expression of MmedSNMP2 was widely found in various tissues,significantly increased at half‐pigmented pupae stage and remained at a relatively constant level during the following developmental stages.It was found that MmedSNMP1 contained eight exons and seven introns,which was highly conserved compared with other insect species.In situ hybridization assay demonstrated that MmedSNMP1 transcript was distributed widely in antennal flagella.Among selected chemosensory genes(odorant binding protein,odorant receptor,and ionotropic receptor genes),MmedSNMP1 only partially overlapped with MmedORco in olfactory sensory neurons of antennae.Subsequent immunolocalization results further indicated that MmedSNMP1 was mainly expressed in sensilla placodea of antennae and possibly involved in perceiving plant volatiles and sex pheromones.These findings lay a foundation for further investigating the roles of SNMPs in the chemosensation of parasitoids.

Molecular cloning and comparative analysis of transcripts encoding chemosensory proteins from two plant bugs, Lygus lineolaris and Lygus hesperus

Chemosensory proteins(CSPs)are soluble carrier proteins typically characterized by a six‐helix bundle structure joined by two disulfide bridges and a conserved Cys spacing pattern(C1‐X6‐8‐C2‐X16‐21‐C3‐X2‐C4).CSPs are functionally diverse with reported roles in chemosensation,immunity,development,and resistance.To expand our molecular understanding of CSP function in plant bugs,we used recently developed transcriptomic resources for Lygus lineolaris and Lygus hesperus to identify 17 and 14 CSP‐like sequences,respectively.The Lygus CSPs are orthologous and share significant sequence identity with previously annotated CSPs.Three of the CSPs are predicted to deviate from the typical CSP structure with either five or seven helical segments rather than six.The seven helix CSP is further differentiated by an atypical C3‐X3‐C4 Cys spacing motif.Reverse transcriptase PCR‐based profiling of CSP transcript abundance in adult L.lineolaris tissues revealed broad expression for most of the CSPs with antenna specific expression limited to a subset of the CSPs.Comparative sequence analyses and homology modeling suggest that variations in the amino acids that comprise the Lygus CSP binding pockets affect the size and nature of the ligands accommodated.

Olfactory receptor gene evolution is unusually rapid across Tetrapoda and outpaces chemosensory phenotypic change

Chemosensation is the most ubiquitous sense in animals,enacted by the products of complex gene families that detect environmental chemical cues and larger-scale sensory structures that process these cues.While there is a general conception that olfactory receptor(OR)genes evolve rapidly,the universality of this phenomenon across vertebrates,and its magnitude,are unclear.The supposed correlation between molecular rates of chemosensory evolution and phenotypic diversity of chemosensory systems is largely untested.We combine comparative genomics and sensory morphology to test whether OR genes and olfactory phenotypic traits evolve at faster rates than other genes or traits.Using published genomes,we identified ORs in 21 tetrapods,including amphibia ns,reptiles,birds,and mammals and compared their rates of evolution to those of orthologous non-OR protein-coding genes.We found that,for all clades investigated,most OR genes evolve nearly an order of magnitude faster than other protein-coding genes,with many OR genes showing signatures of diversifying selection across nearly all taxa in this study.This rapid rate of evolution suggests that chemoreceptor genes are in "evolutionary overdrive,"perhaps evolving in response to the ever-changing chemical space of the environment.To obtain complementary morphological data,we stained whole fixed specimens with iodine,μCT-scanned the specimens,and digitally segmented chemosensory and nonchemosensory brain regions.We then estimated phenotypic variation within traits and among tetrapods.While we found considerable variation in chemosensory structures,they were no more diverse than nonchemosensory regions.We suggest chemoreceptor genes evolve quickly in reflection of an ever-changing chemical space,whereas chemosensory phe no types and processing regions are more conserved because they use a standardized or constrained architecture to receive and process a range of chemical cues.

Recent progress in carbon-dots-based nanozymes for chemosensing and biomedical applications

Nanozymes are nanomaterials with enzyme-like activities that efficiently overcome the drawbacks of natural enzymes in biosensing,detection,and biomedical fields,and they are the most widely used artificial enzymes.Owing to their excellent catalytic characteristics,biocompatibility,and environmental favorability,carbondots-based(CDs) nanozymes have inspired a research upsurge.However,no review focusing on CDs nanozymes has been published,even though substantial advances have been achieved.Herein,the advances,catalytic activities,and applications of CDs nanozymes are highlighted and summarized.In addition,the critical issues and challenges of researching nanozymes are discussed.We hope that this review will broaden the horizons of nanozymes and CDs nanozymes,as well as promote their development.

An Efficient Way for the Recognition of Zinc Ion via the Fluorescence Enhancement

This study concentrates on the spectral and complexing properties of a tetraoxycalix[2]arene[2]triazine derivative bearing two bipyridines （Calix-BIPY2） in a mixture of acetonitrile ： chloroform （4 ： 1, V： V）. The results show that Calix-BIPY2 has a highly selectivity and sensitivity towards Zn2＋ over various competing eations （K＋, Cu2＋, Cd2＋, Co2＋, Fe2＋, Hg2＋, Ag＋, Al3＋ and pb2＋）. The complexation of Zn2＋ induces a remarkable fluorescence enhancement due to combination effects of the binding strength, electron spins state of metal ions, photoinduced charge transfer （PCT） and the rigidity of the complexing unit offered by calixarene-based hosts.