Phosphate-solubilizing bacteria improve the phytoremediation efficiency of Wedelia trilobata for Cu-contaminated soil

In a controlled experiment, we assessed the effect of phosphate-solubilizing bacterium (PSB) on the soil metal (Cu²⁺) phytoremediation by Wedelia trilobata and examined the effect of the interaction of Cu contamination and PSB on the growth of W. trilobata. We also explored the effect of the interaction of Cu contamination and PSB on the soil microflora. The results showed that the removal efficiency of Cu from soil by W. trilobata increased with an increase in the concentration of PSB, and the translocation factors of Cu (i.e., leaf:root and stem:root) were both significantly upregulated by PSB. The PSB significantly promoted the growth of W. trilobata; however, the effect of the Cu–PSB interaction on the leaf net photosynthetic rate (Pn) of W. trilobata was not significant, whereas copper contamination had a significant negative influence on the soil microflora, PSB had a significant positive influence on the soil microflora. Thus, PSB improved the phytoremediation efficiency of W. trilobata in Cu-contaminated soil because of the positive influence on the soil microflora, improving soil quality, which then increased the growth of W. trilobata in Cu-contaminated soil. The vigorous growth of W. trlobata led to higher of Cu absorption and translocation from soil as the ultimate result.     

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The importance of long non‐coding RNAs (lncRNAs) in plant development has been established, but a systematic analysis of lncRNAs expressed during pollen development and fertilization has been elusive. We performed a time series of RNA‐seq experiments at five developmental stages during pollen development and three different time points after pollination in Brassica rapa and identified 12 051 putative lncRNAs. A comprehensive view of dynamic lncRNA expression networks underpinning pollen development and fertilization was provided. B. rapa lncRNAs share many common characteristics of lncRNAs: relatively short length, low expression but specific in narrow time windows, and low evolutionary conservation. Gene modules and key lncRNAs regulating reproductive development such as exine formation were uncovered. Forty‐seven cis‐acting lncRNAs and 451 trans‐acting lncRNAs were revealed to be highly coexpressed with their target protein‐coding genes. Of particular importance are the discoveries of 14 lncRNAs that were highly coexpressed with 10 function‐known pollen‐associated coding genes. Fifteen lncRNAs were predicted as endogenous target mimics for 13 miRNAs, and two lncRNAs were proved to be functional target mimics for miR160 after experimental verification and shown to function in pollen development. Our study provides the systematic identification of lncRNAs during pollen development and fertilization in B. rapa and forms the foundation for future genetic, genomic, and evolutionary studies.     

Characterization of the Treg Response in the Hepatitis B Virus Hydrodynamic Injection Mouse Model

Regulatory T cells (Tregs) play an important role in counter-regulating effector T cell responses in many infectious diseases. However, they can also contribute to the development of T cell dysfunction and pathogen persistence in chronic infections. Tregs have been reported to suppress virus-specific T cell responses in hepatitis B virus (HBV) infection of human patients as well as in HBV animal models. However, the phenotype and expansion of Tregs has so far only been investigated in other infections, but not in HBV. We therefore performed hydrodynamic injections of HBV plasmids into mice and analyzed the Treg response in the spleen and liver. Absolute Treg numbers significantly increased in the liver but not the spleen after HBV injection. The cells were natural Tregs that surprisingly did not show any activation or proliferation in response to the infection. However, they were able to suppress effector T cell responses, as selective depletion of Tregs significantly increased HBV-specific CD8+ T cell responses and accelerated viral antigen clearance. The data implies that natural Tregs infiltrate the liver in HBV infection without further activation or expansion but are still able to interfere with T cell mediated viral clearance.     

Microbial transformation of propenylbenzenes for natural flavour production

Propenylbenzenes are common aromatic compounds that are often used as starting compounds for the production of various flavours. Recently, microbial transformation has emerged as an important approach for producing natural flavours in high quantities. Because the biotransformation processes are environmentally friendly and the products are considered 'natural', flavour production using this method is attracting more and more attention. This paper reviews recent advances in the application of microbial metabolism to propenylbenzenes and in subsequent flavour production. Vanillin, a valuable aromatic compound, is used as a model to show recent progress in high-value natural flavour production. Future research should focus on metabolic-mechanism characterisation and on optimisation of biotransformation to improve the yields of target products for scale-up and industrial use.     

引种期同质园翅荚木主要叶功能性状与种源地环境关系

从比叶面积(SLA)、叶片相对含水量(LRWC)、叶组织密度(LTD)、叶片干物质含量(LDMC)、叶片碳(C)氮(N)磷(P)含量及其化学计量比等方面对在引种期同质园的广西桂林市(GGL)、广西靖西市(GJX)、湖南江华县(HJH)、湖南通道市县(HTD)、广东英德市(GYD)等5翅荚木种源叶片主要功能性状进行差异分析及相关性分析,并研究翅荚木叶功能性状与种源地环境因子的关系。结果显示,(1)不同种源间叶片C、N含量及C/N差异显著,5种源间叶片C含量GYD最高、GGL最低,N含量GJX最高、GYD最低,C/N为GYD最高、GJX最低。(2)比叶面积与叶组织密度呈显著负相关;叶片N含量与C/N和C/P呈显著负相关,与N/P呈显著正相关;C/P与P含量呈显著负相关,与C/N呈显著正相关;C/N与N/P呈显著负相关。(3)翅荚木叶功能性状主要受七月均温、年均温和相对湿度等地理环境因子影响。七月均温与C/P、比叶面积呈正相关,与叶片N含量、叶片干物质含量、叶组织密度呈负相关;年均温与C/N呈正相关,与N/P呈负相关;相对湿度与叶片P含量、叶组织密度呈正相关,与C/P、比叶面积呈负相关。研究结果有助于理解翅荚木对引种区的环境适应特征及其在引种期的生长与生存策略,对探究翅荚木的养分利用策略、揭示其对环境变化的响应机制等具有重要意义,并为相关部门选择适宜的翅荚木引种栽培种源及开展其优良种源的遗传改良等提供理论指导与决策参考。     

Codon Optimization,Expression in Escherichia coli,and Immunogenicity of Recombinant Chinese Sacbrood Virus (CSBV) Structural Proteins VP1, VP2, and VP3

Chinese sacbrood virus (CSBV) is a small RNA virus family belonging to the genus Iflavirus that causes larval death, and even the collapse of entire bee colonies. The virus particle is spherical, non-enveloped, and its viral capsid is composed of four proteins, although the functions of the structural proteins are unclear. In this study, we used codon recoding to express the recombinant proteins VP1, VP2, and VP3 in Escherichia coli. SDS-PAGE analysis and Western blotting revealed that the target genes were expressed at high levels. Mice were then immunized with the purified, recombinant proteins, and antibody levels and lymphocyte proliferation were analyzed by ELISA and the MTT assay, respectively. The results show that the recombinant proteins induced high antibody levels and promoted lymphocyte proliferation. Polyclonal antibodies directed against these proteins will aid future studies of the molecular pathogenesis of CSBV.     

One-stage and two-stage anaerobic digestion of lipid-extracted algae

Waste-grown microalgae are a potentially important biomass for wastewater treatment. The lipid accumulated in microalgae could be utilized as feedstocks for biodiesel production. The algal residues, as major by-products derived from lipid extraction, mainly consist of carbohydrate and protein, making anaerobic digestion an efficient way to recover energy. The conversion of lipid-extracted algal residues into methane plays dual role in renewable energy production and sustainable development of microalgal biodiesel industry. Therefore, an anaerobic fermentation process for investigation of the methane production potential of algal residues was conducted in this paper. The effect of inoculum to substrate ratios (ISRs) on the methane production by anaerobic digestion of Chlorella sp. residue in a single stage was evaluated. The maximum methane yield of 195.6 ml CH₄/g volatile solid (VS) was obtained at an ISR of 1:1. The stability and progress of the reaction from algal residues to methane were monitored by measuring the pH, volatile fatty acids (VFAs), total ammoniacal nitrogen (TAN), and methane volume. Based on the results of one-stage experiments, two-stage technology was proposed and was found to be more suitable for high organic load. The optimum conditions for acidogenesis and methanogenesis are indicated in this paper.