摘要：
Squalene is an important triterpene with a wide range of applications. Given the growing market demand for squalene, the development of microbial cell factories capable of squalene production is considered a sustainable method. This study aimed to investigate the squalene production potential of Yarrowia lipolytica. First, HMG-CoA reductase from Saccharomyces cerevisiae and squalene synthase from Y. lipolytica was co-overexpressed in Y. lipolytica. Second, by enhancing the supply of NADPH in the squalene synthesis pathway, the production of squalene in Y. lipolytica was effectively increased. Furthermore, by constructing an isoprenol utilization pathway and overexpressing YlDGA1, the strain YLSQ9, capable of producing 868.1 mg/L squalene, was obtained. Finally, by optimizing the fermentation conditions, the highest squalene concentration of 1628.2 mg/L (81.0 mg/g DCW) in Y. lipolytica to date was achieved. This study demonstrated the potential for achieving high squalene production using Y. lipolytica.
作者机构：
[Huan Yu; Hong Chen; Ni Li; Hua-Yan Xiao; Gong Chen; Guo-Hua Huang] Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, China;Agriculture and Rural Bureau of Xinhuang Dong Autonomous County, Huaihua, Hunan, China;[Chang-Jin Yang] Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, China<&wdkj&>Agriculture and Rural Bureau of Xinhuang Dong Autonomous County, Huaihua, Hunan, China
通讯机构：
[Gong Chen; Guo-Hua Huang] H;Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, College of Plant Protection, Hunan Agricultural University, Changsha, Hunan, China
关键词：
Heliothis virescens ascovirus 3h (HvAV-3h);ascovirus;insect virus;pathogenicity;structural protein
摘要：
Different pathogenic processes of a virus in different hosts are related to the host individual differences, which makes the virus undergoes different survival pressures. Here, we found that the virions of an insect virus, Heliothis virescens ascovirus 3h (HvAV-3h), had different protein composition when they were purified from different host larval species. These "adaptive changes" of the virions were analyzed in detail in this study, which mainly included the differences of the protein composition of virions and the differences in affinity between virions and different host proteins. The results of this study revealed the flexible changes of viruses to help themselves adapt to different hosts. Also, these interesting findings can provide new insights to improve our understanding of virus adaptability and virulence differentiation caused by the adaptation process.
通讯机构：
[Liu, ZQ ] ;South China Agr Univ, Coll Agr, Guangdong Prov Key Lab Plant Mol Breeding, Guangzhou 510642, Guangdong, Peoples R China.;South China Agr Univ, State Key Lab Conservat & Utilizat Subtrop Agrobio, Guangzhou 510642, Guangdong, Peoples R China.
摘要：
Understanding the evolutionary forces in speciation is a central goal in evolutionary biology. Asian cultivated rice has two subspecies, indica and japonica, but the underlying mechanism of the partial reproductive isolation between them remains obscure. Here we show a presence-absence variation (PAV) at the Se locus functions as an indica-japonica reproductive barrier by causing hybrid sterility (HS) in indica-japonica crosses. The locus comprises two adjacent genes: ORF3 encodes a sporophytic pollen killer, whereas ORF4 protects pollen in a gametophytic manner. In F-1 of indica-japonica crosses, pollen with the japonica haplotype, which lacks the sequence containing the protective ORF4, is aborted due to the pollen-killing effect of ORF3 from indica. Evolutionary analysis suggests ORF3 is a gene associated with the Asian cultivated rice species complex, and the PAV has contributed to the reproductive isolation between the two subspecies of Asian cultivated rice. Our analyses provide perspectives on rice inter-subspecies post-zygotic isolation, and will promote efforts to overcome reproductive barriers in indica-japonica hybrid rice breeding. The mechanisms of the partial reproductive isolation between the two subspecies of rice remains obscure. Here, the authors show that the two adjacent genes form a killer-protector system to induce hybrid male sterility and reproductive isolation between indica and japonica.
关键词：
Township health center;exploratory spatiotemporal data analysis;healthcare service capacity;quantile regression;unexpected output superefficiency SBM
摘要：
INTRODUCTION: This study analyzes the efficiency, spatiotemporal evolution, and influencing factors of provincial township health centers' healthcare service capacity in China. METHOD: It utilizes an unexpected output super-efficiency slacks-based measure (SBM) model, exploratory spatiotemporal data analysis methods, and a quantile regression model. RESULTS: The results show that the healthcare service capacity of township health centers is better in provinces with a larger proportion of hierarchical diagnoses and treatments pilot projects in cities, and the regional efficiency trend is ordered central > eastern > western > northeastern. The healthcare service capacity of provincial township health centers mainly shows significant spatial correlation and a spatiotemporal distribution pattern of "high agglomeration, low differentiation." DISCUSSION: Rural population density and per capita GDP significantly improve the healthcare service capacity of township health centers, while local governments' healthcare and health expenditure increases the healthcare service capacity of township health centers in certain quantiles. The urbanization rate and per capita disposable income inhibit the improvement of the healthcare service capacity of township health centers in certain quantiles. The provinces should accelerate the promotion of hierarchical diagnoses and treatment pilot projects in cities and establish national cooperative development models to promote public health.
通讯机构：
[Mei Liu; Hong Chen] A;Authors to whom correspondence should be addressed.<&wdkj&>Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, No.3 Taicheng Road, Xianyang 712100, China<&wdkj&>Authors to whom correspondence should be addressed.<&wdkj&>College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
摘要：
Simultaneous anammox and denitrification (SAD) is an efficient approach to treat wastewater having a low C/N ratio; however, few studies have investigated a combination of SAD and partial nitritation (PN). In this study, a lab-scale up-flow blanket filter (UBF) and zeolite sequence batch reactor (ZSBR) were continuously operated to implement SAD and PN advantages, respectively. The UBF achieved a high total nitrogen (TN) removal efficiency of over 70% during the start-up stage (days 1-50), and reached a TN removal efficiency of 96% in the following 90 days (days 51-140) at COD/NH4+-N ratio of 2.5. The absolute abundance of anammox bateria increased to the highest value of 1.58 x 10(7) copies/mu L DNA; Comamon- adaceae was predominant in the UBF at the optimal ratio. Meanwhile, ZSBR was initiated on day 115 as fast nitritation process to satisfy the influent requirement for the UBF. The combined process was started on day 140 and then lasted for 30 d, during the combined process, between the two reactors, the UBF was the main contributor for TN (66.5% +/- 4.5%) and COD (71.8% +/- 4.9%) removal. These results demonstrated that strong SAD occurred in the UBF when following a ZSBR with in-situ NOB elimination. This research presents insights into a novel biological nitrogen removal process for low C/N ratio wastewater treatment. (C) 2022 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
