The type VI protein secretion system contributes to biofilm formation and seed‐to‐seedling transmission of Acidovorax citrulli on melon

The type VI protein secretion system (T6SS) is essential for the virulence of several Gram‐negative bacteria. In this study, we identified a T6SS gene cluster in Acidovorax citrulli, a plant‐pathogenic bacterium that causes bacterial fruit blotch (BFB) of cucurbits. One T6SS cluster, of approximately 25 kb in length and comprising 17 genes, was found in the A. citrulli AAC00‐1 genome. Seventeen A. citrulli mutants were generated, each with a deletion of a single T6SS core gene. There were significant differences in BFB seed‐to‐seedling transmission between wild‐type A. citrulli strain, xjl12, and ΔvasD, ΔimpK, ΔimpJ and ΔimpF mutants (71.71%, 9.83%, 8.41%, 7.15% and 5.99% BFB disease index, respectively). In addition, we observed that these four mutants were reduced in melon seed colonization and biofilm formation; however, they were not affected in virulence when infiltrated into melon seedling tissues. There were no significant differences in BFB seed‐to‐seedling transmission, melon tissue colonization and biofilm formation between xjl12 and the other 13 T6SS mutants. Overall, our results indicate that T6SS plays a role in seed‐to‐seedling transmission of BFB on melon.     

The Limits of Authenticity in Vietnamese Consumer Markets

In this article, I address the saliency of the concept of "authenticity" in contexts of international law and anthropological inquiry. Using my research findings in Ho Chi Minh City (HCMC), Vietnam, I show that although Vietnamese shoppers distinguish between what they term real and fake goods, they do not share with foreign corporations and international trade organizations a preoccupation with product and brand authenticity. To make this point, I describe four types of goods—model goods, mimic goods, real goods, and fake goods—employed by shoppers in HCMC, and discuss why they have little in common with notions of "authenticity" and "ownership" inherent in international standards of intellectual property. I argue that these conceptual differences in the commercial sphere challenge claims about the universal applicability of intellectual property rights laws and also encourage anthropologists to ask whether authenticity is always a useful tool of cross-cultural understanding.     

以CRISPR/Cas9专利为例的知识产权教育

随着世界经济全球化步伐的加快, 知识产权的重要性凸显。高校是知识产权意识和能力教育的主战场。我国现有知识产权教育与专业的密切程度急需提高。文章结合全球首个CRISPR/Cas9专利权的授权公布和作者授课经历, 提出了一种新的知识产权普及教育模式, 将知识产权教育分为启蒙教育和深入研修两个阶段。第一阶段将知识产权教育与专业课课程无缝整合, 后一阶段主要针对有志于发展成为知识产权专业人才的学生。我们认为这种教学模式的推广将解决现有知识产权教育中教材的欠缺以及教师的不足, 有利于知识产权意识在生物医学等理工科学生的普及。遗传学在生物医学中具有特别重要的地位, 因此, 文章以遗传学最近的热点技术之一——基于CRISPR/Cas的基因组编辑新工具为例进行阐述。CRISPR/Cas从最初的微生物遗传学发现到成为基因组编辑的重要工具, 贯穿了基础研究转化为关键技术的全过程, 可以很好体现生物医学相关的知识产权教育的精髓。     

Dual regulation effect and mechanism of human myeloid-derived suppressor cells on anticolorectal cancer cells activity of Vγ9Vδ2 T cells

Myeloid-derived suppressor cells (MDSC) are a group of immature inhibitory cells of bone marrow origin. Human γδ T cells (mainly Vγ9Vδ2 T cells) have emerged as dominant candidates for cancer immunotherapy because of their unique recognition pattern and broad killing activity against tumor cells. Intestinal mucosal intraepithelial lymphocytes are almost exclusively γδ T cells, so it plays an important role in inhibiting the development of colorectal cancer. In this study, we investigated the effects and molecular mechanism of human MDSC on anticolorectal cancer cells activity of Vγ9Vδ2 T cells. Our results suggested that MDSC can reduce the NKG2D expression of Vγ9Vδ2 T cells through direct cell–cell contact, which is associated with membrane-type transforming growth factor-β. In contrast, MDSC can increase Vγ9Vδ2 T cells activation and production of IFN-γ, perforin, Granzyme B through direct cell–cell contact. This may be related to the upregulation of T-bet in Vγ9Vδ2 T cells by MDSC. However, MDSC had a dominant negative regulatory effect on the anticolorectal cancer cells activity of Vγ9Vδ2 T cells. Our study provides a theoretical basis for the immune regulatory function of human MDSC on γδ T cells. This will be conducive to the clinical development of a new antitumor therapy strategy.     

Role of the conserved threonine 309 in mechanism of oxidation by cytochrome P450 2D6

Based on sequence alignments and homology modeling, threonine 309 in cytochrome P450 2D6 (CYP2D6) is proposed to be the conserved I-helix threonine, which is supposed to be involved in dioxygen activation by CYPs. The T309V mutant of CYP2D6 displayed a strong shift from O-dealkylation to N-dealkylation reactions in oxidation of dextromethorphan and 3,4-methylenedioxymethylamphetamine. This may be explained by an elevated ratio of hydroperoxo-iron to oxenoid-iron of the oxygenating species. In consistence, using cumene hydroperoxide, which directly forms the oxenoid-iron, the T309V mutant again selectively catalyzed the O-dealkylation reactions. The changed ratio of oxygenating species can also explain the decreased activity and changed regioselectivity that were observed in 7-methoxy-4-(aminomethyl)-coumarin and bufuralol oxidation, respectively, by the T309V mutant. Interestingly, the T309V mutant always showed a significantly increased, up to 75-fold, higher activity compared to that of the wild-type when using cumene hydroperoxide. These results indicate that T309 in CYP2D6 is involved in maintaining the balance of multiple oxygenating species and thus influences substrate and regioselectivity.     

Ant-mediated expansion of an obligate seeder species during the first years after fire

Most obligate seeder species build up a soil seed bank that is associated with massive seed germination in the year immediately after a fire. These species are also shade‐intolerant and disappear when vegetation cover closes, creating unsuitable conditions for seedling recruitment. The only way for these plants to expand their populations is when habitats suitable for seedling recruitment arise (i.e. in years immediately after a fire). However, short primary seed dispersal of obligate seeders does not allow these plants to colonise the suitable habitats, and these habitats can only be colonised by secondary seed dispersion. We hypothesised that Fumana ericoides, an obligate‐seeding small shrub, not only establishes abundantly in the first year after fire, but also expands its local range in the following years due to secondary dispersal by ants while suitable habitats are still available. We tested this hypothesis using experimental studies and a simulation model of potential population expansion in a recently burned area. Results showed that F. ericoides not only established prolifically in the year immediately after fire, but was also able to recruit new individuals and expand its population in the years following the fire, despite a low germination rate and short primary seed dispersal. Ant‐mediated seed dispersal and availability of suitable habitats were key factors in this phenomenon: ants redistributed seeds in suitable habitats while they were available, which accelerated the expansion of F. ericoides because new plants established far away from the core population.     

葡萄属一新名和一新种

描述了自甘肃南部发现的葡萄属一新种,文县蘡薁Vitis wenxianensis W.T.Wang。此新种与特产浙江的三出蘡薁V.bryoniifolia Bunge var.ternata(W.T.Wang)C.L.Li有很近的亲缘关系,二者可能是由蘡薁V.bryoniifolia Bunge衍生而出的一对姊妹群。基于上述认识,将三出蘡薁由变种提升至种的等级,但由于存在一个于1871年发表的种名V.ternata Baker,因此,必须为三出蘡薁拟定一新名。