Mitochondria are crucial to the hypoxia response of aerobic organisms. However, mitochondrial mechanisms for hypoxia adaptation remain largely unknown. We conducted a comparative study on the mitochondrial hypoxia response and adaptation of the Tibetan Plateau and North China lowland populations of migratory locusts,Locusta migratoria.Compared with lowland locusts, Tibetan locusts presented significantly higher hypoxia tolerance and a better-maintained mitochondrial structure in flight muscles under oxygen partial pressure of 1.6 kPa. The hypoxic treatment inhibited the NADH-linked oxidative phosphorylation (OXPHOS) significantly in both locust populations, but to a less extent in Tibetan locusts. Among the critical components of OXPHOS, only cytochrome c oxidase (COX) exhibited significantly higher activity in Tibetan locusts under normoxia and hypoxia. Pharmacological interventions using NaN₃confirmed that COX activity inhibition reduced hypoxia tolerance by downregulating OXPHOS in both locust populations. The enhanced COX activity was caused not by protein content, but by elevated catalytic efficiency resulting from the increased ferrocytochrome c affinity of COX and the increased electron transport rate via catalytic redox centres. These findings reveal a novel mechanism that confers mitochondrial robustness against hypoxia by modulating the COX activity, which represents an adaptation to permanent hypoxia in the Tibetan Plateau.

Nattokinase is a serine protease in the subtilisin family which is produced by Bacillus subtilis subsp. natto and exhibits vigorous fibrinolytic activity that has been suggested to be able to prevent and treat thromboembolic diseases. In this study, WTC016, a spore-forming and rod-shaped bacterium with fibrinolytic activity was successfully isolated from soil, which was identified as Bacillus subtilis subsp. natto based on morphological and physiological tests, and phylogenetic analysis of 16S rRNA and gyrA. According to the growth curve of WTC016, the nattokinase production reached the highest amount in the stationary phase. To optimize the liquid fermentation condition for nattokinase yield of WTC016, further optimal tests of four factors, including the temperature, pH, inoculum size, and loading volume, followed by orthogonal test of all these factors, was performed. The optimal fermentation conditions were determined as 30 °C, 7.0 pH, 2% inoculum size, and 60 mL of loading volume in 250 mL conical flask, which indicates the highest nattokinase production of 3284 ± 58 IU/mL while fermented for 26 h. This work laid the foundation for producing nattokinase using Bacillus subtilis subsp. natto WTC016.

Panonychus citri is one of the most damaging pests of horticultural crops. Conventional control of this pest population through pesticides has led to the enhanced pest resistance. Management of P. citri population through RNAi, is still largely unknown. In oviparous organisms, fabrication and development of yolk protein play a vital role in the reproduction. Vitellin (Vn) is the source of eggs storage that helps in proper functioning of Vitellogenin (Vg) and Vitellogenin receptor (VgR). VgR is very compulsory protein for the development of Vg into oocytes. In the current study, Vg (PcVg) and VgR (PcVgR) genes were studied and their expressions at different developmental stages were quantified by RT-qPCR. Females treated with dsRNA of PcVg and PcVgR genes exhibited reduction in gene expression. Down regulation of target genes significantly effected oviposition and reduced the egg laying capacity up to 48% as compared to control (ds-egfp). Synergistic effect of target gene’s dsRNA was also accessed that reduced the egg laying up to 60.42%. Furthermore, combination of target dsRNA on deutonymph and protonymph also resulted in 67% and 70% reduction in eggs, respectively. Synergistic effect of dsRNA at 1000 ng/ul resulted in longer life span as compared to control treatments. This study suggests to develop a new strategy of P. citri population control by reducing its reproduction.

Fruit of Citrus wilsonii Tanaka called as “Xiang yuan” in Chinese, which means fragrant and round. It was widely used in the pharmaceutical and food industries. This fruit has well-known health benefits such as antioxidant, radical scavenging, and anti-inflammatory. Naringin, deacetylnomilin, citric acid, limonin, and nomilin were the characteristic components of Citrus wilsonii Tanaka. Although the fruit of Citrus wilsonii Tanaka possessed many applications, there was a lack of research on the growth period and drying process. In this study, plant metabolomics was used to analyze the biomarkers of the growth period, and appearance indicators and metabolites abundance were combined for the analysis of change regularities of the growth period. The representative differential metabolites of naringin, citric acid, and limonin were screened out, and the abundance of these components was relatively highest in the middle of the growth period. Therefore, the fruit of Citrus wilsonii Tanaka should be harvested before it turned yellow completely, which could effectively ensure the content of potential active ingredients. In the comparison of different drying methods, citric acid and naringin were considered to be representative differential components, but limonoids were relatively stable and not easily affected by drying methods. Naringin was an index component that could not only be reflected the maturity but also related to different drying methods. Considering its physical and chemical properties and its position, naringin had the potential to be a biomarker of Citrus wilsonii Tanaka.