The functional link between TCTP and Drsl1 in deltamethrin-stressed Drosophila Kc cells.

Translationally controlled tumor protein (TCTP) is a growth and development related protein found in almost all eukaryotes and can be involved in a variety of cellular life activities. Our previous studies found that TCTP is involved in the response of Drosophila Kc cells to deltamethrin (DM) stimulation, and it may be a candidate gene related to DM stress. Therefore, we would further investigate the functions of TCTP and its mechanism under DM stress. The qPCR results showed that the expression level of Drsl1 increasing first and then decreasing with the change of DM concentration and treatment duration. The optimal concentration was 20 ppm and the optimal time was 24 h. qPCR and WB results together showed that the expression levels of TCTP and Drsl1 were positively correlated. The flow cytometry showed the expression levels of TCTP and Drsl1 in deltamethrin-stressed cells are related to apoptosis. The apoptosis rate reached the highest level in the cells with simultaneous interference of both genes. Taken together, our data mainly suggest that TCTP interacts with Drsl1 in response to DM stress in Drosophila Kc cells, which helps to investigate the mechanisms of DM toxicity and the mechanisms by which insects develop resistance to it.

The exact status and synonyms of three Chinese Afronurus Lestage, 1924 established by Navs in 1936 (Ephemeroptera: Heptageniidae).

Navs named more than 20 mayfly species from China but most of them are not associated with currently known specimens. In 2021, we found three common species of Chinese Afronurus Lestage, 1924 (Heptageniidae), which genitalia and color patterns match three species described and illustrated by Navs in 1936. Therefore, three new synonyms are established: Afronurus pallescens (Navs, 1936) (=Cinygmina obliquistriata You et al., 1981, syn. nov.), Afronurus kiangsuensis (Puthz, 1971) (renamed from Ecdyonurus hyalinus Navs, 1936= Cinygmina rubromaculata You et al., 1981, syn. nov.), Afronurus costatus (Navs, 1936) (=Cinygmina yixingensis Wu You, 1986, syn. nov.). As the type specimens for Navas three species are supposed to be lost, neotypes are designated for them.

A Review of the Genus Cloeon from Chinese Mainland (Ephemeroptera: Baetidae).

The widely distributed and species diverse genus Cloeon Leach, 1815 has never been reviewed in China, although nine species names have been reported from this country. After checking types of two species (C. viridulum and C. apicatum) and newly collected materials from more than 50 sites, four species are recognized, compared, and photographed in this research. Among them, the species C. bicolor Kimmins, 1947 is first recorded in China, and its nymphs are described for the first time. The distribution in China of two other species (C. dipterum (Linnaeus, 1761) and C. harveyi (Kimmins, 1947)) are also confirmed. The two species established by Navás (C.apicatum Navás, 1933 = C. navasi Bruggen, 1957, C. pielinum Navás, 1933, syn. nov.) and the species C. micki named by Tong and Dudgeon in 2021 are synonymized with C. viridulum Navás, 1931-the fourth species in this study. Furthermore, the C. virens Klapálek, 1905 from the Chinese mainland, found by Ulmer in 1925, is also regarded as the last species. Among the four species, the C. dipterum and C. harveyi seem closer because of the similar female color patterns of their stigma and ventral abdomen, while the species C. viridulum and C. bicolor are more alike because they have neither pigmented stigma nor stripes on abdominal sterna.

Mitochondrial genomes of eight Scelimeninae species (Orthoptera) and their phylogenetic implications within Tetrigoidea.

Scelimeninae is a key member of the pygmy grasshopper community, and an important ecological indicator. No mitochondrial genomes of Scelimeninae have been reported to date, and the monophyly of Scelimeninae and its phylogenetic relationship within Tetrigidae is still unclear. We sequenced and analyzed eight nearly complete mitochondrial genomes representing eight genera of Scelimeninae. These mitogenomes ranged in size from 13,112 to 16,380 bp and the order of tRNA genes between COII and ATP8 was reversed compared with the ancestral order of insects. The protein-coding genes (PCGs) of tetrigid species mainly with the typical ATN codons and most terminated with complete (TAA or TAG) stop codons. Analyses of pairwise genetic distances showed that ATP8 was the least conserved gene within Tetrigidae, while COI was the most conserved. The longest intergenic spacer (IGS) region in the mitogenomes was always found between tRNASer(UCN) and ND1. Additionally, tandem repeat units were identified in the longest IGS of three mitogenomes. Maximum likelihood (ML) and Bayesian Inference (BI) analyses based on the two datasets supported the monophyly of Tetriginae. Scelimeninae was classified as a non-monophyletic subfamily.

Characterization of the complete mitochondrial genome of Ergatettix serrifemora (Orthoptera: Tetrigidae) from China and its phylogenetic analysis.

The mitochondrial genome (mitogenome) of the Ergatettix serrifemora (Orthoptera: Tetrigidae: Tetriginae) was sequenced and annotated. The assembled mitochondrial genome was 14,947 bp, containing 45.8% of A, 15.7% of C, 9.6% of G and 28.9% of T, respectively, which is the classical structure for insect mitogenome. The region that we failed to sequence was between rrnS and trnI, and generally contained a putative AT-rich region. Twelve PCGs started with typical ATN codon and eleven ended with complete stop codons (three with TAG, eight with TAA). The phylogenetic trees in the current study confirmed that E. serrifemora was clustered with other Tetriginae species, and this study would improve our understanding for the mitogenomes of Tetrigoidea.

Analysis of UB and L40, related to deltamethrin stress in the diamondback moth, Plutella xylostella (L.).

Pests have been subjected to heavy selection by insecticide pressure, producing greater and more serious resistance. It is extremely valuable to identify the resistance genes that are relevant for pest control. In our previous studies, we reported that UBL40 is the deltamethrin resistance-associated gene. UBL40 is cleaved by specific endopeptidases to release UB and L40. Therefore, further we compared the expression of UB and L40 in different tissues from larvae of the diamondback moth using a deltamethrin-resistant (DR) strain and a deltamethrin-sensitive (DS) strain. The results showed that both UB and L40 knockdown significantly reduced the level of resistance to deltamethrin and clearly decreased the survival rate in P. xylostella after 72 h. These results provide evidence that UB and L40 both play roles in the regulation of deltamethrin resistance, which could help elucidate the resistance mechanisms and identify new target genes associated with deltamethrin resistance in P. xylostella.

Analysis of translation control tumor protein related to deltamethrin stress in Drosophila kc cells.

The translation control tumor protein (TCTP) is a kind of conservative, common and important molecule, several functions (such as regulating cell cycle, apoptosis and calcium binding) have been reported. However, few academic researches for role of TCTP in insecticides stress were made so far. In this research, Drosophila kc cells treated with different doses of deltamethrin at different times, indicated that the expression of TCTP reached the highest level when the cells were treated with 20 ppm of deltamethrin at 24 h. The results showed that TCTP expression is associated with deltamethrin stress. To investigate the functional relationship between this gene and deltamethrin resistance, RNA interference (RNAi) and cell transfection were utilized. TCTP knockdown significantly reduced the level of resistance of RNAi-treated cells, and the overexpressions of TCTP in Drosophila kc cells conferred a degree of protection against deltamethrin. Flow cytometry data showed increased apoptosis rate of RNAi-treated cells and decreased apoptosis following cell transfection. These results represent the first evidence that TCTP plays an important role in the regulation of deltamethrin resistance. Therefore, this study could help us to elucidate the environmental toxicity of deltamethrin and new target genes associated with resistance.

Analysis of Ran related to pesticide resistance in Drosophila Kc cells.

Pesticides have been used extensively for pest control, resulting in serious pesticide resistance. It is extremely valuable to identify the resistance genes related to pest control. In our previous studies, we reported that Ran is the deltamethrin (DM) resistance-associated gene. To clarify whether Ran is also related to the resistance of other pesticides, we selected four kinds of pesticides, including parathion, DDT, carbaryl and pleocidin, for further study. The results showed that Ran could be up-regulated by all pesticides. We further verified the relationship between Ran and resistance to the 4 pesticides by Ran RNAi, Ran overexpression and cell apoptosis. We found that the dsRNA of Ran induced more cell apoptosis than the control. Ran overexpression can significantly improve cell tolerance to various pesticides. These results demonstrate that Ran is associated with the resistance to and tolerance of multiple pesticides. Our evidence suggests the Ran is a potential molecular target gene of resistance control.

Identification of proteasome subunit beta type 2 associated with deltamethrin detoxification in Drosophila Kc cells by cDNA microarray analysis and bioassay analyses.

Insecticide deltamethrin resistance has presented a difficult obstacle for pest control and the resistance development is complex and associated with many genes. To better understand the possible molecular mechanisms involved in DM stress, in this study, cDNA microarray analysis was employed. 448 differentially expressed genes with at least a 2-fold expression difference were identified in Drosophila cells after DM exposure. Moreover, some genes were confirmed with qPCR, which yielded results consistent with the microarray analysis. Three members of the ubiquitin-proteasome system were significantly elevated in DM-stressed cells, suggesting that the ubiquitin-proteasome pathway may play an important role in DM detoxification. The proteasome beta2 subunit (Prosbeta2) is a member of 20S proteasome subunit family, which forms the proteolytic core of 26S proteasome. Whether Prosbeta2 participates in DM detoxification requires further study. RNAi and heterologous expression were conducted to investigate the contribution of Prosbeta2 in DM detoxification. The results revealed Prosbeta2 knockdown significantly reduce the level of DM detoxification in RNAi-treated cells after 48 h. Overexpression of Prosbeta2 increased cellular viability. These detoxification results represent the first evidence that Prosbeta2 plays a role in the detoxification of DM, which may provide new idea and target for studying the molecular mechanisms of insect resistance.