Functional evaluation of the insulin/insulin-like growth factor signaling pathway in determination of wing polyphenism in pea aphid

Wing polyphenism is a common phenomenon that plays key roles in environmental adaptation of insects.Insulin/insulin-like growth factor signaling(IIS)pathway is a highly conserved pathway in regulation of metabolism,development,and growth in metazoans.It has been reported that IS is required for switching of wing morph in brown planthopper via regulating the development of the wing pad.However,it remains elusive whether and how IIS pathway regulates transgenerational wing dimorphism in aphid.In this study,we found that pairing and solitary treatments can induce pea aphids to produce high and low percentage winged offspring,respectively.The expression level of ILP5(insulin-like peptide 5)in maternal head was significantly higher upon solitary treatment in comparison with pairing,while silencing of ILP5 caused no obvious change in the winged offspring ratio.RNA interference-mediated knockdown of FoxO(Forkhead transcription factor subgroup O)in stage 20 embryos significantly increased the winged offspring ratio.The results of pharmacological and quantitative polymerase chain reaction experiments showed that the embryonic insulin receptors may not be involved in wing polyphenism.Additionally,ILP4 and ILP11 exhibited higher expression levels in 1st wingless offspring than in winged offspring.We demonstrate that FoxO negatively regulates the wing morph development in embryos.ILPs may regulate aphid wing polyphenism in a developmental stage-specific manner.However,the regulation may be not mediated by the canonical IIS pathway.The findings advance our understanding of IIS pathway in insect transgenerational wing polyphenism.

Structural Variations in Wing Patterning of Seasonal Polyphenic Melanitis leda (Satyrinae)

Seasonal polyphenism is a common phenomenon observed among members of the Lepidopteran subfamily Satyrinae. Melanitis leda, being a member of that subfamily, exhibits seasonal variation in terms of wing patterning. In butterflies, wing patterning is due to the nanostructural architecture of the scales, which reflects and refracts incident light, with or without the combination of pigments. The current scanning electron, fluorescence and optical microscope study divulge fine structural and signal changes that occur with different season in the scales of M. leda and give rise to the different wing pattern in butterfly. The structural and consequent signal changes are likely to be correlated with behavioural processes such as mate selection and escape from predation.

Identification of structurally and functionally significant deleterious nsSNPs of GSS gene: in silico analysis

It is becoming more and more apparent that most genetic disorders are caused by biochemical abnormalities. Recent advances in human genome project and related research have showed us to detect and understand most of the inborn errors of metabolism. These are often caused by point mutations manifested as single-nucleotide-polymorphisms (SNPs). The GSS gene inquested in this work was analyzed for potential mutations with the help of computational tools like SIFT, PolyPhen and UTRscan. It was noted that 84.38% nsSNPs were found to be deleterious by the sequence homology based tool (SIFT), 78.13% by the structure homology based tool (PolyPhen) and 75% by both the SIFT and PolyPhen servers. Two major mutations occurred in the native protein (2HGS) coded by GSS gene at positions R125C and R236Q. Then a modeled structure for the mutant proteins (R125C and R236Q) was proposed and compared with that of the native protein. It was found that the total energy of the mutant (R125C and R236Q) proteins were -31893.846 and -31833.818 Kcal/mol respectively and that of the native protein was -31977.365 Kcal/mol. Also the RMSD values between the native and mutant (R125C and R236Q) type proteins were 1.80? and 1.54?. Hence, we conclude based on our study that the above mutations could be the major target mutations in causing the glutathione synthetase deficiency.

Body color plasticity of Diaphorina citri reflects a response to environmental stress

Body color polyphenism is common in Diaphorina citri.Previous studies compared physiological characteristics in D.citri,but the ecological and biological significance of its body color polyphenism remains poorly understood.We studied the ecological and molecular effects of stressors related to body color in D.citri.Crowding or low temperature induced a high proportion of gray morphs,which had smaller bodies,lower body weight,and greater susceptibility to the insecticide dinotefuran.We performed transcriptomic and metabolomics analysis of 2 color morphs in D.citri.Gene expression dynamics revealed that the differentially expressed genes were predominantly involved in energy metabolism,including fatty acid metabolism,amino acid metabolism,and carbohydrate metabolism.Among these genes,plexin,glycosidase,phospholipase,take out,trypsin,and triacylglycerol lipase were differentially expressed in 2 color morphs,and 6 hsps(3 hsp70,hsp83,hsp90,hsp68)were upregulated in gray morphs.The metabolome data showed that blue morphs exhibited a higher abundance of fatty acid and amino acid,whereas the content of carbohydrates was elevated in gray morphs.This study partly explains the body color polyphenism of D.citri and provides insights into the molecular changes of stress response of D.citri.

The structure of the compound eyes and phototaxis in two phenotypes of the bean pest Callosobruchus maculatus(Coleoptera:Bruchinae)

Callosobruchus maculatus(Fabricius,1775)(Coleoptera:Bruchinae)is a destructive agricultural pest that is harmful to beans worldwide and an important quarantine pest in China.It was divided into two phenotypes based on polyphenism:normal and flight forms.In this study,we first compared the morphological structures of the compound eyes of the two forms.According to the results of scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(micro-CT),and computer three-dimensional reconstruction,there are no differences in the structures of the compound eyes between the normal and flight forms except for the number of ommatidia.From the internal structure,the compound eyes have a biconvex cornea with open rhabdom and acone eye,crystalline cone directly connected with rhabdom,and no clear zone.It is a kind of apposition eye.Ommatidia facets range in shape from quadrilateral to hexagonal and some irregular shapes.On electroretinograms(ERGs),the normal and flight forms showed different spectral sensitivities:the normal form had the strongest response to ultraviolet light,whereas the flight form had the strongest response to white light.Behavioral assays revealed that the normal and flight forms showed completely opposite phototaxis behaviors;the flight form exhibited positive phototaxis,whereas the normal form exhibited negative phototaxis.This study not only enriches our knowledge on coleopteran compound eyes but also provides a foundation for in-depth research on the photoreceptor mechanisms of compound eyes,which may be useful in pest control management.

Molecular markers of phase transition in locusts

The changes accompanying the transition from the gregarious to the solitary phase state in locusts are so drastic that for a long time these phases were considered as distinct species. It was Boris Uvarov who introduced the concept of polyphenism. Decades of research revealed that phase transition implies changes in morphometry, the color of the cuticle, behavior and several aspects of physiology. In particular, in the recent decade, quite a number of molecular studies have been undertaken to uncover phase-related differences. They resulted in novel insights into the role of corazonin, neuroparsins, some protease inhibitors, phenylacetonitrile and so on. The advent of EST-databases of locusts （e.g. Kang et al., 2004） is a most encouraging novel development in physiological and behavioral locust research. Yet, the answer to the most intriguing question, namely whether or not there is a primordial molecular inducer of phase transition, is probably not within reach in the very near future.

人类Ⅱ相药物毒物代谢酶非同义单核苷酸多态性的表型预测：分子进化观

药物毒物代谢酶编码区的非同义单核苷酸多态性(nsSNPs)导致氨基酸改变,从而可能改变相应蛋白质的功能,使人体对有关药物毒物产生异常反应,亦与疾病易感性关联.在人类Ⅱ相代谢酶基因中已发现大量nsSNPs,但对这些酶nsSNPs基因型和表型间的关系了解甚少.本研究从Ensembl基因组数据库和NCBISNP数据库识别出104个人类Ⅱ相酶基因的923个经确认的nsSNPs.用PolyPhen,Panther和SNAP算法预测,发现44%～59%的nsSNPs影响到蛋白质功能.本研究的预测结果与已有实验研究证据基本吻合.68%的已知有害nsSNPs被正确预测为有害.本研究识别出多个尚未经实验研究的功能氨基酸.Panther和PolyPhen的预测结果吻合,SNAP非中性预测结果与PolyPhen预测分值亦吻合.进化上非中性的(去稳定化的)氨基酸替换可能是Ⅱ相酶活性改变,产生疾病易感性和药物/外源物毒性的致病基础.本研究还在有害nsSNPs预测的框架内阐明了Ⅱ相酶的分子进化模式.

Phenotype prediction of nonsynonymous single nucleotide polymorphisms in human phase II drug/xenobiotic metabolizing enzymes: perspectives on molecular evolution

Nonsynonymous single nucleotide polymorphisms (nsSNPs) in coding regions can lead to amino acid changes that might alter the protein’s function and account for susceptibility to disease and altered drug/xenobiotic response. Many nsSNPs have been found in genes encoding human phase II metabolizing enzymes; however, there is little known about the relationship between the genotype and phenotype of nsSNPs in these enzymes. We have identified 923 validated nsSNPs in 104 human phase II enzyme genes from the Ensembl genome database and the NCBI SNP database. Using PolyPhen, Panther, and SNAP algorithms, 44%?59% of nsSNPs in phase II enzyme genes were predicted to have functional impacts on protein function. Predictions largely agree with the available experimental annotations. 68% of deleterious nsSNPs were correctly predicted as damaging. This study also identified many amino acids that are likely to be functionally critical, but have not yet been studied experimentally. There was significant concordance between the predicted results of Panther and PolyPhen, and between SNAP non-neutral predictions and PolyPhen scores. Evolutionarily non-neutral (destabilizing) amino acid substitutions are thought to be the pathogenetic basis for the alteration of phase II enzyme activity and to be associated with disease susceptibility and drug/xenobiotic toxicity. Furthermore, the molecular evolutionary patterns of phase II enzymes were characterized with regards to the predicted deleterious nsSNPs.