Discovery of a natural thiamine adenine nucleotide

Several important cofactors are adenine nucleotides with a vitamin as the catalytic moiety. Here, we report the discovery of the first adenine nucleotide containing vitamin B1: adenosine thiamine triphosphate (AThTP, 1), or thiaminylated ATP. We discovered AThTP in Escherichia coli and found that it accumulates specifically in response to carbon starvation, thereby acting as a signal rather than a cofactor. We detected smaller amounts in yeast and in plant and animal tissues.     

Retrovirus-polymer complexes: study of the factors affecting the dose response of transduction

We have previously shown that complexes of Polybrene (PB), chondroitin sulfate C (CSC), and retrovirus transduce cells more efficiently than uncomplexed virus because the complexes are large and sediment, reaching the cells more rapidly than by diffusion. Transduction reaches a peak at equal weight concentrations of CSC and PB and declines when the dose of PB is higher or lower than CSC. We hypothesized that the nonlinear dose response of transduction was a complex function of the molecular characteristics of the polymers, cell viability, and the number of viruses incorporated into the complexes. To test this hypothesis, we formed complexes using an amphotropic retrovirus and several pairs of oppositely charged polymers and used them to transduce murine fibroblasts. We examined the effect of the type and concentration of polymers used on cell viability, the size and charge of the complexes, the number of viruses incorporated into the complexes, and virus binding and transduction. Transduction was enhanced (2.5- to 5.5-fold) regardless of which polymers were used and was maximized when the number of positive charge groups was in slight excess (15-28%) of the number of negative charge groups. Higher doses of cationic polymer were cytotoxic, whereas complexes formed with lower doses were smaller, contained fewer viruses, and sedimented more slowly. These results show that the dose response of transduction by virus-polymer complexes is nonlinear because excess cationic polymer is cytotoxic, whereas excess anionic polymer reduces the number of active viruses that are delivered to the cells.     

Specificity and genetic polymorphism in the Vfm quorum sensing system of plant pathogenic bacteria of the genus Dickeya

The Vfm quorum sensing (QS) system is preponderant for the virulence of different species of the bacterial genus Dickeya. The vfm gene cluster encodes 26 genes involved in the production, sensing or transduction of the QS signal. To date, the Vfm QS signal has escaped detection by analytical chemistry methods. However, we report here a strain-specific polymorphism in the biosynthesis genes vfmO and vfmP, which is predicted to be related to the production of different analogues of the QS signal. Consequently, the Vfm communication could be impossible between strains possessing different variants of the genes vfmO/P. We constructed three Vfm QS biosensor strains possessing different vfmO/P variants and compared these biosensors for their responses to samples prepared from 34 Dickeya strains possessing different vfmO/P variants. A pattern of specificity was demonstrated, providing evidence that the polymorphism in the genes vfmO/P determines the biosynthesis of different analogues of the QS signal. Unexpectedly, this vfmO/P-dependent pattern of specificity is linked to a polymorphism in the ABC transporter gene vfmG, suggesting an adaptation of the putative permease VfmG to specifically bind different analogues of the QS signal. Accordingly, we discuss the possible involvement of VfmG as co-sensor of the Vfm two-component regulatory system.     

地市尺度气候调节服务评估——以福州市为例

生态系统服务是衔接生态系统功能和人类福利的桥梁,气候调节服务在生态系统服务中占有极其重要的地位。对气候调节服务发生的全过程进行评估,对科学开展生态系统服务评估具有重要意义。本研究以福州市为案例,开展地市尺度气候调节服务评估,分析气候调节服务在行政单元、地类尺度上的时空变化特征。结果表明: 2015、2018年,福州市气候调节服务总实物量分别为4.01×10¹² MJ(价值量6139.44亿元,GDP为5618.08亿元)和4.66×10¹² MJ(价值量7140.02亿元,GDP为7856.81亿元),气候调节服务价值大致与当年GDP相当。主要的土地利用/覆被类型是森林、耕地、水域,分别占福州市国土面积的57%、15%和9%;水域对福州市气候调节服务贡献最大,2018年贡献度超过60%,高于林地(12%)及耕地(13%)。建成区、东部农耕区域气候调节服务价值较低。2015、2018年,福州市土地利用/覆被变化面积为1805.5 km²,变化最大的用地类型是耕地、林地,主要的土地利用转移方向是耕地与林地、林地与园地、耕地与城镇村及工矿用地之间的转化;气候调节服务总实物量变化了6.74×10¹¹ MJ,相应的价值变化量为1035.8亿元;气候调节服务变化集中在闽侯、闽清、永泰等中西部地区,以及罗源、福清等西部山区;水域的气候调节服务变化最剧烈,水域类型转化会产生极为强烈的气候调节服务变化,远高于其他用地类型转换的效果。     

2020年邳州市草地贪夜蛾初迁虫源的迁入路径及气象背景

2020年江苏省邳州市于3月31日发现草地贪夜蛾Spodoptera frugiperda成虫,远早于该地区2019年草地贪夜蛾的始见期6月份。为明确该地区草地贪夜蛾种群性质,利用昆虫轨迹分析方法,模拟分析了2020年江苏省邳州市早期发现的草地贪夜蛾的迁飞路径及天气背景场。结果表明：邳州市2019年12月-2020年2月温度低,草地贪夜蛾无法在此地越冬存活,2020年3月31日所诱捕的草地贪夜蛾为外地迁入,其虫源来自广西和广东西部的周年繁殖区;虽然邳州市3月份常年盛行北风和西北风,西南风发生概率低导致草地贪夜蛾迁入邳州市概率较小,但2020年3月底850 hPa的强西南气流为草地贪夜蛾从我国华南地区迁入邳州市提供了条件。本研究结果阐明了在极端条件下草地贪夜蛾从华南地区迁入江苏省的可能性,丰富了江苏省草地贪夜蛾春季早期迁入的理论依据。     

A novel microRNA signature predicts vascular invasion in hepatocellular carcinoma

Vascular invasion (VI) in hepatocellular carcinoma (HCC) is an important clinical parameter to predict survival. In this study, we collected microRNA (miRNA) expression data from HCC patients using The Cancer Genome Atlas database and identified a novel miRNA signature associated with VI. First, we categorized HCC patients into groups with or without VI (VI+ and VI−). We identified three miRNAs (miRNA-210, miRNA-10b, and miRNA-9-1) that were associated with VI according to a Kaplan–Meier analysis. This three-miRNA signature exhibited good predictive ability for VI in patients with HCC according to a receiver operating characteristic curve analysis at 1, 3, and 5 years. Patients with HCC with a high risk score exhibited a trend toward worse outcomes as determined by multivariable Cox regression and stratified analyses. This three-miRNA signature provides an accurate prediction of VI and can be used as an independent prognostic indicator for predicting VI in HCC patients.     

A century of conservation: The ongoing recovery of Svalbard reindeer

Several caribou and reindeer (Rangifer tarandus) populations have experienced recent population declines, often attributed to anthropogenic stressors such as harvesting, landscape fragmentation, and climate change. Svalbard reindeer (R. t. platyrhynchus), the wild reindeer subspecies endemic to the high-Arctic Svalbard archipelago, was protected in 1925, after most subpopulations had been eradicated by harvest. Although direct pressure from harvest has ceased, indirect anthropogenic stressors from environmental changes have increased in this climate change hot spot. An assessment of the current distribution and abundance is therefore urgently needed. We combined distance sampling (300 km transects, n = 489 reindeer groups) and total counts (1,350 km², n = 1,349 groups) to estimate the Svalbard reindeer distribution and abundance across its entire range, which we compared with historical data from the literature and radiocarbon-dated bones. Reindeer have now recolonized nearly all non-glaciated land (i.e., areas occupied prior to human presence), and their spatial variation in abundance reflects vegetation productivity. Independent of vegetation productivity, however, recently recolonized areas have lower reindeer densities than areas not subject to past extirpation. This suggests that recovery from past overharvesting is still in progress. These incompletely recovered areas are potential targets for increased monitoring frequency and maintaining strict conservation to follow the Svalbard management goal (i.e., virtually untouched wilderness areas). Because of such ongoing recolonization, possibly combined with vegetation greening effects of recent warming, our status estimate of Svalbard reindeer abundance (22,435 [95% CI = 21,452–23,425]) is more than twice a previous estimate based on opportunistic counts. Thus, although our study demonstrates the successful outcome of strict harvesting control implemented a century ago, current and future population trajectories are likely shaped by climate change. © 2019 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Generation and characterization of a functional human adipose-derived multipotent mesenchymal stromal cell line

Multipotent mesenchymal stromal cells (MSC) and MSC-derived products have emerged as promising therapeutic tools. To fully exploit their potential, further mechanistic studies are still necessary and bioprocessing needs to be optimized, which requires an abundant supply of functional MSC for basic research. To address this need, here we used a novel technology to establish a human adipose-derived MSC line with functional characteristics representative of primary MSC. Primary MSC were isolated and subjected to lentiviral transduction with a library of expansion genes. Clonal cell lines were generated and evaluated on the basis of their morphology, immunophenotype, and proliferation potential. One clone (K5 iMSC) was then selected for further characterization. This clone had integrated a specific transgene combination including genes involved in stemness and maintenance of adult stem cells. Favorably, the K5 iMSC showed cell characteristics resembling juvenile MSC, as they displayed a shorter cell length and enhanced migration and proliferation compared with the non-immortalized original primary MSC (p < 0.05). Still, their immunophenotype and differentiation potential corresponded to the original primary MSC and the MSC definition criteria, and cytogenetic analyses revealed no clonal aberrations. We conclude that the technology used is applicable to generate functional MSC lines for basic research and possible future bioprocessing applications.