Evaluation of a remnant lake sturgeon population’s utility as a source for reintroductions in the Ohio River system

The selection of an appropriate source population may be crucial to the long-term success of reintroduction programs. Appropriate source populations often are those that originate from the same genetic lineage as native populations. However, source populations also should exhibit high levels of genetic diversity to maximize their capacity to adapt to variable environmental conditions. Finally, it is preferable if source populations are genetically representative of historical lineages with little or no contamination from non-native or domesticated stocks. Here, we use nuclear (microsatellite) and cytoplasmic (mitochondrial control region) markers to assess the genetic suitability of a potential source population inhabiting the White River in Indiana: the last extant lake sturgeon population in the Ohio River drainage. The White River population exhibited slightly lower levels of genetic diversity than other lake sturgeon populations. However, the population’s two private microsatellite alleles and three private haplotypes suggest a unique evolutionary trajectory. Population assignment tests revealed only two putative migrants in the White River, indicating the population has almost completely maintained its genetic integrity. Additionally, pairwise F _ST estimates indicated significant levels of genetic divergence between the White River and seven additional lake sturgeon populations, suggesting its genetic distinctiveness. These data indicate that the White River population may be the most suitable source population for future lake sturgeon reintroductions throughout the Ohio River drainage. Furthermore, the White River population appears to be a reservoir of unique genetic information and reintroduction may be a necessary strategy to ensure the persistence of this important genetic lineage.     

Community structure in ichneumonid parasitoids at different spatial scales

The processes underlying parasitoid community structure are little known. Stochastic niche-apportionment models provide one route to underlying assemblage rules in this and other groups. Previous work has applied this approach to parasitoids found on single host species in single populations. However, parasitoid communities are known to extend across multiple hosts and scales. The patterns of relative abundances generated by five niche-apportionment models were compared to those observed in assemblages of two sub-families of the Ichneumonidae, the Diplazontinae and Pimplinae, at landscape and patch scales, Yorkshire, UK. Three of the five models produced patterns that were significantly different to the observed pattern for all taxonomic levels at both spatial scales. The Diplazontinae fit the random fraction (RF) model at the landscape scale in broadleaved woods. This suggests that hierarchical structuring and biotic interactions may play a role in the structuring of Diplazontinae assemblages at this scale. In contrast the Pimplinae fit the RF model only at the patch scale and only at one site. However, the Pimplini tribe (all chiefly parasitoids of Lepidoptera) fit the random assortment (RA) model at both the landscape and the patch scales, whilst the Ephialtini tribe (wide range of hosts) fit no model at either scale. The ecological interpretation of the RA model suggests that the Pimplini tribe is an unsaturated assemblage, where some of the total available resources are unused. Our results show, through the fit of mechanistic niche-apportionment models, that the processes that may structure ichneumonid parasitoid assemblages are not consistent across taxa and spatial scales.     

On a genetic assessment of the adaptedness of forest reproductive material

Assessment of the adaptedness of forest tree populations and the reproductive material derived from them is largely based on historical records and observations on extant distributions of phenotypic traits. Genetic criteria are, if at all, usually considered only in the form of heuristic reasoning. A main reason for this situation lies in the lack of operational concepts that clearly distinguish between viability selection and adaptation. The present paper makes an attempt towards this aim by showing that the adaptational optimization of viability selection processes rests on three constituent features which allow minimization of the implied overall mortality at each relevant selection stage and across all of these stages. Indices are developed that measure the degree of adaptational optimization of viability selection. The concept and its indices are applied to an analysis of isozyme data obtained for an approved beech seed stand and reproductive material derived from this stand. An approved seed stand is required to be adapted, and this property is expected to be preserved in the derived reproductive material. Our observations revealed substantial degrees of overall reductions and suboptimal selection during the production process. Suboptimality is unevenly distributed over the stages of the production process, and stages of strongest suboptimality vary among gene loci. A preliminary explanation is given for a conspicuous effect on selective optimality that is consistently observable at the stage of seedling development across all loci. Received: 2 February 2001 / Accepted: 25 June 2001     

Topography, independent component analysis and dipole source analysis of movement related potentials

The objective of this study was to test, in single subjects, the hypothesis that the signs of voluntary movement-related neural activity would first appear in the prefrontal region, then move to both the medial frontal and posterior parietal regions, progress to the medial primary motor area, lateralize to the contralateral primary motor area and finally involve the cerebellum (where feedback-initiated error signals are computed). Six subjects performed voluntary finger movements while DC coupled EEG was recorded from 64 scalp electrodes. Event-related potentials (ERPs) averaged on the movements were analysed both before and after independent component analysis (ICA) combined with dipole source analysis (DSA) of the independent components. Both a simple topographic analysis of undecomposed ERPs and the ICA/DSA analysis suggested that the original hypothesis was inadequate. The major departure from its predictions was that, while activity over many brain regions did appear at the expected times, it also appeared at unexpected times. Overall, the results suggest that the neuroscientific ‘standard model’, in which neural activity occurs sequentially in a series of discrete local areas each specialized for a particular function, may reflect the true situation less well than models in which large areas of brain shift simultaneously into and out of common activity states. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Standardizing CAR-T therapy: Getting it scaled up

CAR-T therapy, grafting the specificity of a monoclonal antibody onto a T cell to target certain cancer cells, has been recognized as a promising therapeutic approach for cancer control as evidenced by the two CAR-T products proved by FDA in 2017. However, the unique heterogeneity of CAR-T therapy has restricted its production in a limited number of institutions and made it a boutique oncotherapy. By reviewing outstanding issues surrounding the commercial scale production of CAR-T therapy, we conclude that achieving mass production of CAR-T therapy without sacrificing its personalized nature is a worldwild challenge for making CAR-T a key element in the next generation of precision medicine, which can be achieved by standardizing 7 prominent factors that collectively determine the scale of CAR-T manufacturing.     

Particulate organic carbon in the estuarine turbidity maxima of the Gironde,Loire and Seine estuaries: origin and lability

A study of the particulate organic carbon (POC) in the estuarine turbidity maxima (ETMs) of the three major French macrotidal estuaries shows that the average contents are 1.5, 3.3 and 3.1% (expressed in % of dry suspended sediment) in the Gironde, Loire and Seine Estuaries, respectively. There is no seasonal variation of POC contents in the Gironde Estuary, whereas, they often increase in the Loire and the Seine Estuaries in spring and summer. The lability of the estuarine particulate organic matter was estimated by two analyses: 1/labile organic matter was measured as the organic carbon loss during incubation tests over one month; 2/ the hydrolysable organic fraction was determined after 6N HCl digestion. The organic fractions of the ETMs are mainly refractory. Any increase in the amount of POC as compared to the background levels (cited above) is always correlated to an increase of organic matter lability. The yearly average fluvial contributions by various particulate organic pools (soil and litter organic matter; organic matter of phytoplanktonic and human origin) that enter the three estuaries were quantified. In the Garonne River, soil and litter are the major (90%) POC sources. In the Loire system, due to the eutrophication of the river water, phytoplankton contributes up to 50% of the total POC load. In the Seine river, soil and litter contribute 70% of the total POC input; POC of human origin is also significant (10%), due to the impact of the City of Paris (10 million inhabitants). The lability of the different types of organic matter ranks as follows: phytoplankton ∼litter > human-origin organic matter >> soil. By combining the POC budgets and the lability of each type of organic fraction, it was possible to explain why the POC of the three ETMs is different and characterizes its refractory vs. labile nature.     

Molecular physiology of higher plant sucrose transporters

Sucrose is the primary product of photosynthetic CO(2) fixation that is used for the distribution of assimilated carbon within higher plants. Its partitioning from the site of synthesis to different sites of storage, conversion into other storage compounds or metabolic degradation involves various steps of cell-to-cell movement and transport. Many of these steps occur within symplastic domains, i.e. sucrose moves passively cell-to-cell through plasmodesmata. Some essential steps, however, occur between symplastically isolated cells or tissues. In these cases, sucrose is transiently released into the apoplast and its cell-to-cell transport depends on the activity of plasma membrane-localized, energy dependent, H(+)-symporting carrier proteins. This paper reviews the current knowledge of sucrose transporter physiology and molecular biology.     

基于生态系统服务视角的生态风险评估及生态修复空间辨识——以长江源区为例

辨识生态修复空间是进行生态恢复与重建的重要前提。在流域尺度,以长江源区为研究对象,构建了青藏高原生态修复空间辨识框架,以定量方法为主、定性方法为辅,依次开展了区域主导生态系统服务评估、生态风险评估、植被退化评价,识别了生态修复优先区,提出了系统保护与修复建议。结果表明：①2000年、2015年长江源区生态系统服务呈现从西北部向东南部增加的趋势,单位面积水源涵养量、土壤保持量分别下降18.06%、22.9%,单位面积防风固沙量增加8.84%,NPP未发生显著变化。②生态风险以1、2、3级中低风险为主,面积占比共计74.41%;4级区面积占比19.35%;5级区面积占比仅6.24%,集中分布于称多、玉树和唐古拉山。不同风险等级呈圈层递减的分布格局。③2000-2015年NDVI增长率为0.013%/a。绝大部分草地未发生退化,轻度退化草地面积占比0.82%;中重度退化草地面积占比1.09%;④严格施行划区轮牧和草畜平衡管理,坚持以自然修复为主、辅以人工修复,治理黑土滩、沙化土地、水土流失。对于昂日曲、麻多乡北、加巧曲等9个地块（393.75 km²）,严格封禁,针对性地实施沙化地修复、黑土滩修复、草原有害生物防控工程等人工干预和保护措施。研究结果能为青藏高原生态系统服务功能维护和提升、退化生态系统的修复治理提供理论依据和技术支撑。     

探讨笔石反射率对奥陶系、志留系烃源岩成熟度的指示作用

通过对塔里木盆地、鄂尔多斯、江苏等地区奥陶系,志留系笔石反射率的研究,以该地区有机地球化学等综合分析指标为中介,分析笔石反射率与等效镜质体反射率之比关系,建立笔石反射率对奥陶系,志留系烃源岩成熟度的评价标准。认为笔石最大反射率,随机反射率对奥陶率,志留系烃源岩成熟度有良好的指示作用。发现笔石有机质在热演化过程中,由于笔石纺锤层等生物结构的存在,使温度成为影响笔石热演化程度的主要因素。笔石的热演化有