Effects of Varroa destructor on temperature and humidity conditions and expression of energy metabolism genes in infested honeybee colonies

The regulation of dermal mesenchymal stem cells on keratinocytes apoptosis

Dermal mesenchymal stem cells (DMSCs) are progenitor cells with the capacity of self-renewal, multilineage differentiation, and immunomodulation, which were reported to induce the proliferation of keratinocytes, however the regulation on keratinocytes apoptosis was unknown. In this study, we isolated DMSCs from normal skin and co-cultured with keratinocytes, and then detected apoptosis of keratinocytes by flow cytometry and expression of apoptosis associated proteins by western blot. The mRNA expression profile of normal DMSCs was investigated by RNA sequencing. The results of our study presented that the DMSCs promoted HaCaT cells apoptosis both in early apoptotic state (13.8 vs. 2.9, p < 0.05) and late apoptotic state (4.2 vs. 0.7, p < 0.05). The expression of apoptosis associated proteins caspase-3 (3.51 vs. 1.99, p < 0.05) and lymphoid enhancer-binding factor 1 (3.10 vs. 0.83, p < 0.05) were upregulated. However, the cell cycle protein cyclin E1 was similar (9.38 vs. 9.05, p > 0.05). Moreover, 33 genes with the function of induced cell apoptosis were highly expressed in DMSCs, including insulin-like growth factor-binding protein 4 (2828.13), IGFBP7 (1805.69), cathepsin D (1694.34), cathepsin B (CTSB, 1641.40) and dickkopf WNT signaling pathway inhibitor 1 (DKK1, 384.79). This study suggested DMSCs induce the apoptosis of keratinocytes through non-G1/S phase blockade via highly expression of apoptosis inducer.

Genome-wide identification and expression analysis of the E2 gene family in potato

E2 (ubiquitin conjugating enzymes) is an important part of the ubiquitin-proteasome pathway. These enzymes have a significant role to play during plant growth and development, which can response to various stresses. To date, the E2 family has been reported in some high plants, but the genome-wide characterization of this gene family in potato remains unknown. In the present study, 57 putative StUBCs were identified, which were clustered into eight subgroups based on phylogeny. The introns varied in numbers 0 to 9. The highest numbers of introns were 5, which accounted for 31.57%. The analysis of gene duplication showed that 22 StUBC genes were involved in 13 segmental duplication events, while no tandem duplication was found in StUBC genes. According to gene ontology analysis (GO), StUBC family major function is protein binding and ion binding. The RNA sequencing data revealed that 15 StUBC genes were highly expressed in different organs and tubers. 27 StUBC genes were up-regulated under 50 µM ABA treatments. Moreover, the RNA-seq data and qRT-PCR analysis indicated that 17 StUBC genes responded to heat stress. 8 StUBC genes responded to salt stress according to qRT-PCR analysis, and StUBC2, StUBC12, StUBC30 and StUBC13 were predominant expression. The result of this research could provide valuable information to insight into potato E2 family and establish a foundation for further to elucidate function of E2 genes.

Sublethal effects of imidacloprid on targeting muscle and ribosomal protein related genes in the honey bee Apis mellifera L

A sublethal concentration of imidacloprid can cause chronic toxicity in bees and can impact the behavior of honey bees. The nectar- and water-collecting, and climbing abilities of bees are crucial to the survival of the bees and the execution of responsibilities in bee colonies. Besides behavioral impact, data on the molecular mechanisms underlying the toxicity of imidacloprid, especially by the way of RNA-seq at the transcriptomic level, are limited. We treated Apis mellifera L. with sublethal concentrations of imidacloprid (0.1, 1 and 10 ppb) and determined the effect on behaviors and the transcriptomic changes. The sublethal concentrations of imidacloprid had a limited impact on the survival and syrup consumption of bees, but caused a significant increase in water consumption. Moreover, the climbing ability was significantly impaired by 10 ppb imidacloprid at 8 d. In the RNA-seq analysis, gene ontology (GO) term enrichment indicated a significant down-regulation of muscle-related genes, which might contribute to the impairment in climbing ability of bees. The enriched GO terms were attributed to the up-regulated ribosomal protein genes. Considering the ribosomal and extra-ribosomal functions of the ribosomal proteins, we hypothesized that imidacloprid also causes cell dysfunction. Our findings further enhance the understanding of imidacloprid sublethal toxicity.

Virus and dsRNA-triggered transcriptional responses reveal key components of honey bee antiviral defense

Recent high annual losses of honey bee colonies are associated with many factors, including RNA virus infections. Honey bee antiviral responses include RNA interference and immune pathway activation, but their relative roles in antiviral defense are not well understood. To better characterize the mechanism(s) of honey bee antiviral defense, bees were infected with a model virus in the presence or absence of dsRNA, a virus associated molecular pattern. Regardless of sequence specificity, dsRNA reduced virus abundance. We utilized next generation sequencing to examine transcriptional responses triggered by virus and dsRNA at three time-points post-infection. Hundreds of genes exhibited differential expression in response to co-treatment of dsRNA and virus. Virus-infected bees had greater expression of genes involved in RNAi, Toll, Imd, and JAK-STAT pathways, but the majority of differentially expressed genes are not well characterized. To confirm the virus limiting role of two genes, including the well-characterized gene, dicer, and a probable uncharacterized cyclin dependent kinase in honey bees, we utilized RNAi to reduce their expression in vivo and determined that virus abundance increased, supporting their involvement in antiviral defense. Together, these results further our understanding of honey bee antiviral defense, particularly the role of a non-sequence specific dsRNA-mediated antiviral pathway.