Recent advances in next generation sequencing (NGS) (e.g. metagenomic and transcriptomic sequencing) have facilitated the discovery of a large number of new insect viruses, but the characterization of these viruses is still in its infancy. Here, we report the discovery, using RNA-seq, of three new partiti-like viruses from African armyworm, Spodoptera exempta (Lepidoptera: Noctuidae), which are all vertically-transmitted transovarially from mother to offspring with high efficiency. Experimental studies show that the viruses reduce their host's growth rate and reproduction, but enhance their resistance to a nucleopolyhedrovirus (NPV). Via microinjection, these partiti-like viruses were transinfected into a novel host, a newly-invasive crop pest in sub-Saharan Africa (SSA), the Fall armyworm, S. frugiperda. This revealed that in this new host, these viruses appear to be deleterious without any detectable benefit; reducing their new host's reproductive rate and increasing their susceptibility to NPV. Thus, the partiti-like viruses appear to be conditional mutualistic symbionts in their normal host, S. exempta, but parasitic in the novel host, S. frugiperda. Transcriptome analysis of S. exempta and S. frugiperda infected, or not, with the partiti-like viruses indicates that the viruses may regulate pathways related to immunity and reproduction. These findings suggest a possible pest management strategy via the artificial host-shift of novel viruses discovered by NGS.

Glucocorticoid (GC)-induced osteoporosis (GIO) is one of the most common secondary and iatrogenic forms of osteoporosis. GCs are widely used in clinical therapy and play a key role in the normal regulation of bone remodeling. However, the prolonged and high-dose administration of GCs results in the occurrence of osteoporosis, which is partially due to the dysfunction and apoptosis of osteoblasts and osteocytes. The aim of the present study was to investigate the effects of gastrodin, a natural bioactive compound isolated from the traditional Chinese herbal agent Gastrodia elata, on GC-treated MC3T3-E1 murine osteoblastic cells. MC3T3-E1 cells were exposed to dexamethasone (DEX), with or without gastrodin pretreatment, and cell viability was measured by the Cell Counting Kit-8 (CCK-8) assay. Quantitative polymerase chain reaction analysis was performed to evaluate osteogenic gene expression, and cellular alkaline phosphatase (ALP) activity was measured as well. Alizarin Red staining of calcium deposits was found to reflect the degree of osteoblast maturity. Western blotting was performed to determine the expression of osteogenic and adipogenic differentiation key proteins, as well as nuclear factor-like 2 (NRF2) pathway-related proteins. Annexin V-fluorescein isothiocyanate/propidium iodide flow cytometric analysis was performed to determine osteoblast apoptosis. JC-1 staining was used to detect the changes of the mitochondrial membrane potential in cells. The results revealed that gastrodin prevented the decrease in cell viability caused by DEX-induced MC3T3-E1 cell dysfunction, and that groups pretreated with gastrodin exhibited higher mRNA levels of osteogenic genes, such as Runx2, osterix, bone morphogenetic protein-2 and osteocalcin. Furthermore, treatment with both DEX and gastrodin was associated with increased ALP activity in MC3T3-E1 cells, as well as more calcium deposits, compared with cells treated with DEX alone. In addition, gastrodin increased osteogenic key marker protein Runx2 while activating NRF2 and downstream effector protein expression. Therefore, gastrodin may have the potential to reduce DEX-induced cell apoptosis and increase the mitochondrial membrane potential against DEX. These results demonstrated that gastrodin was able to prevent and/ or delay DEX-induced osteoporosis by improving osteoblast function, and these protective effects were verified in an animal model.

The comprehensive transcriptome analysis of rice female-sterile line and wild-type line ovule provides an important clue for exploring the regulatory network of the formation of rice fertile female gametophyte. Ovules are the female reproductive tissues of rice (Oryza sativa L.) and play a major role in sexual reproduction. To investigate the potential mechanism of rice female gametophyte fertility, we used RNA sequencing, combined with genetic subtraction, to compare the transcriptome of the ovules of a high-frequency female-sterile line (fsv1) and a rice wild-type line (Gui 99) during ovule development. Ovules were harvested at three developmental stages: ovule containing megaspore mother cell in meiosis process (stage 1), ovule containing functional megaspore in mitosis process (stage 2), and ovule containing mature female gametophyte (stage 3). Six cDNA libraries generated a total of 42.2 million high-quality clean reads that aligned with 30,204 genes. The comparison between the fsv1 and Gui 99 ovules identified a large number of differentially expressed genes (DEGs), i.e., 45, 495, and 932 DEGs at the three ovule developmental stages, respectively. From the comparison of the two rice lines, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and MapMan analyses indicated that a large number of DEGs associated with starch and sucrose metabolism, plant hormone signal transduction, protein modification and degradation, oxidative phosphorylation, and receptor kinase. These DEGs might play roles in ovule development and fertile female gametophyte formation. Many transcription factor genes and epigenetic-related genes also exhibit different expression patterns and significantly different expression levels in two rice lines during ovule development, which might provide important information regarding the abortive mechanism of the female gametophyte in rice.

MicroRNAs (miRNAs/miRs) are post-transcriptional regulators that serve important roles in osteoclastogenesis and bone metabolism; however, the roles of miRNAs have not been completely clarified. The present study aimed to investigate the effects of miR-100-5p on the mechanism of liver-bone endocrine metabolism. A miRNA microarray analysis was conducted to evaluate the miRNA expression profile during receptor activator of nuclear factor-κB ligand-stimulated osteoclastogenesis. Hematoxylin and eosin and tartrate-resistant acid phosphatase staining were performed to analyze the trabecular bone microstructure and osteoclast differentiation. The mRNA and protein expression levels were assessed by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The results revealed that in vitro osteoclast differentiation and in vivo bone resorption were suppressed by miR-100-5p overexpression. In vivo, a decrease in miR-100-5p and an increase in FGF21 were simultaneously observed in mice following ovariectomy (OVX). Bioinformatics analysis and experimental data confirmed that FGF21 was a direct target of miR-100-5p. Conversely, augmentation of miR-100-5p using a specific agomir in OVX-operated mice decreased the levels of FGF21 in the serum and liver, and prevented osteoclastogenesis and bone loss. The present study revealed that FGF21 may be a signal molecule associated with the mechanism of liver-bone endocrine metabolism and may be targeted by miR-100-5p. In addition, miR-100-5p may serve an important role in protecting against OVX-induced osteoporosis.