Insight into the bovine milk peptide LPcin‐YK3 selection in the proteolytic system of Lactobacillus species

Antimicrobial peptides are class of small, positively charged peptides known for their broad‐spectrum antimicrobial activity. Antimicrobial activities for most antimicrobial peptides have largely remained elusive, particularly in the lactic acid bacteria. However, recently our investigation using LPcin‐YK3, an antimicrobial peptide from bovine milk, suggests that in vitro antimicrobial activity was reduced over 100‐fold compared with pathogenic bacteria. Additionally, for the structural study of how antimicrobial peptide undergoes its reaction at the proteolytic pathway of lactic acid bacteria based on degradation assay and propidium iodide staining, we performed molecular docking for interaction between oligopeptide‐binding protein A and LPcin‐YK3 peptide. Given that degradation related to the LPcin‐YK3 peptide in lactic acid bacteria proteolytic system, the inhibitory inactivity of LPcin‐YK3 against beneficial lactic acid bacteria strains may be one of the primary pharmacological properties of recombinant peptide discovered in bovine milk. These results provide structural and functional insights into the proteolytic mechanism and possibility as a putative substrate of oligopeptide‐binding protein A in respect of LPcin‐YK3 peptide.     

Climate change fingerprints in recent European plant phenology

A paper published in Global Change Biology in 2006 revealed that phenological responses in 1971–2000 matched the warming pattern in Europe, but a lack of chilling and adaptation in farming may have reversed these findings. Therefore, for 1951–2018 in a corresponding data set, we determined changes as linear trends and analysed their variation by plant traits/groups, across season and time as well as their attribution to warming following IPCC methodology. Although spring and summer phases in wild plants advanced less (maximum advances in 1978–2007), more (~90%) and more significant (~60%) negative trends were present, being stronger in early spring, at higher elevations, but smaller for nonwoody insect‐pollinated species. These trends were strongly attributable to winter and spring warming. Findings for crop spring phases were similar, but were less pronounced. There were clearer and attributable signs for a delayed senescence in response to winter and spring warming. These changes resulted in a longer growing season, but a constant generative period in wild plants and a shortened one in agricultural crops. Phenology determined by farmers’ decisions differed noticeably from the purely climatic driven phases with smaller percentages of advancing (~75%) trends, but farmers’ spring activities were the only group with reinforced advancement, suggesting adaptation. Trends in farmers’ spring and summer activities were very likely/likely associated with the warming pattern. In contrast, the advance in autumn farming phases was significantly associated with below average summer warming. Thus, under ongoing climate change with decreased chilling the advancing phenology in spring and summer is still attributable to warming; even the farmers’ activities in these seasons mirror, to a lesser extent, the warming. Our findings point to adaptation to climate change in agriculture and reveal diverse implications for terrestrial ecosystems; the strong attribution supports the necessary mediation of warming impacts to the general public.     

Transmission competence of a new mesonivirus,Yichang virus,in mosquitoes and its interference with representative flaviviruses

Advances in technology have greatly stimulated the understanding of insect-specific viruses (ISVs). Unfortunately, most of these findings are based on sequencing technology, and laboratory data are scarce on the transmission dynamics of ISVs in nature and the potential effects of these viruses on arboviruses. Mesonivirus is a class of ISVs with a wide geographical distribution. Recently, our laboratory reported the isolation of a novel strain of mesonivirus, Yichang virus (YCV), from Culex mosquitoes, China. In this study, the experimental infection of YCV by the oral route for adult and larvae mosquitoes, and the vertical transmission has been conducted, which suggests that YCV could adopt a mixed-mode transmission. Controlled experiments showed that the infectivity of YCV depends on the mosquito species, virus dose, and infection route. The proliferation curve and tissue distribution of YCV in Cx. quinquefasciatus and Ae. albopictus showed that YCV is more susceptible to Ae. albopictus and is located in the midgut. Furthermore, we also assessed the interference of YCV with flaviviruses both in vitro and in vivo. YCV significantly inhibited the proliferation of DENV-2 and ZIKV, in cell culture, and reduced transmission rate of DENV-2 in Ae. albopictus. Our work provides insights into the transmission of ISVs in different mosquito species during ontogeny and their potential ability to interact with mosquito-borne viruses.     

Trigonostemons G and H,dinorditerpenoid dimers with axially chiral biaryl linkage from Trigonostemon chinensis

Trigonostemons G and H, two novel dimeric dinorditerpenoids, were isolated from the stem barks of Trigonostemon chinensis. Their planar structures and relative configurations were established by extensive analysis of spectroscopic data. Trigonostemons G and H possess a homodimeric biaryl skeleton obtained from two rearranged chiral nonracemic abietane-type dinorditerpenes through an axially chiral biaryl 11,11′-linkage. Torsional scan and computation of the transition states were carried out to estimate the rotational energy barrier, and the axial chirality (aS) was determined by time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. The positive n-π* ECD transitions of the isolated carbonyl chromophore above 300 nm could be used to determine the central chirality of trigonostemon G independently by ECD calculations of the diastereomers.     

谷氨酸棒杆菌碱基编辑的条件优化

近年来,基于CRISPR/Cas9的碱基编辑技术因其具有不产生DNA双链断裂、无需外源DNA模板、不依赖宿主同源重组修复的优势,已经逐渐发展成为一种强大的基因组编辑工具,在动物、植物、酵母和细菌中得到了开发和应用。研究团队前期已在重要的工业模式菌株谷氨酸棒杆菌中开发了一种多元自动化的碱基编辑技术MACBETH,为进一步优化该方法,提高碱基编辑技术在谷氨酸棒杆菌中的应用效率,本研究首先在谷氨酸棒杆菌中构建了基于绿色荧光蛋白(GFP)的检测系统:将GFP基因的起始密码子ATG人工突变为ACG,GFP无法正常表达,当该密码子的C经编辑后恢复为T,即实现GFP蛋白的复活,结合流式细胞仪分析技术,可快速衡量编辑效率。然后,构建针对靶标位点的碱基编辑工具,经测试,该位点可成功被编辑,在初始编辑条件下碱基编辑效率为(13.11±0.21)%。在此基础上,通过对不同培养基类型、诱导初始OD600、诱导时间、诱导物浓度进行优化,确定最优编辑条件是:培养基为CGXII,初始OD600为0.05,诱导时间为20 h,IPTG浓度为0.01 mmol/L。经过优化,编辑效率达到(30.35±0.75)%,较初始条件提高了1.3倍。最后,选取原编辑条件下编辑效率较低的位点,进行了优化后编辑条件下的编辑效率评估,结果显示,不同的位点在最优编辑条件下的编辑效率提高了1.7–2.5倍,进一步证实该优化条件的有效性及通用性。研究结果为碱基编辑技术在谷氨酸棒杆菌中更好的应用提供了重要的参考价值。     

军曹鱼催乳素受体PRLR1基因的克隆及其在不同盐度条件下mRNA表达差异

催乳素受体通过结合催乳素,能调节鱼体渗透压。为研究催乳素受体1(PRLR1)在高盐水体和低盐水体中对军曹鱼(Rachycentron canadum)的渗透调节作用,利用cDNA末端快速扩增(RACE-PCR)技术,获得了军曹鱼PRLR1全长cDNA序列。该基因全长为2629 bp,包含1953 bp的开放阅读框ORF,可编码650个氨基酸。氨基酸序列包含了2个纤维连接蛋白3型结构域(FN3)、保守的WS区和box1。采用qRT-PCR技术,检测不同盐度(10‰、30‰和35‰)条件下鳃、肠、体肾中PRLR1基因mRNA表达情况。结果显示,PRLR1基因在军曹鱼的各个组织中均有表达,其中鳃表达量最高,其次是肌肉、体肾和肠,而在胃、脾、脑和心脏中则微量表达。低盐组、正常组和高盐组中,PRLR1基因的表达量均为鳃最高;肠次之;体肾最低。随着盐度提高,PRLR1基因的鳃、肠和体肾组织表达量变化规律均呈逐步下降趋势。以上结果反映了军曹鱼PRLR1在渗透压器官中的功能差异性,说明PRLR1在军曹鱼渗透压调节上具有重要作用。