Identification of rosmarinic acid and sulfated flavonoids as inhibitors of microfouling on the surface of eelgrass Zostera marina

A bioassay-guided approach was used to identify defense compounds that are present on the surface of Zostera marina and which inhibit settlement of microfoulers at natural concentrations. Moderately polar eelgrass surface extracts inhibited the settlement of seven marine bacteria and one yeast that originated from non-living substrata. In contrast, five other bacterial strains that had been directly isolated from eelgrass surfaces were all insensitive, which suggested a selective effect of surface metabolites on the microbial communities present on eelgrass. Bioassay-guided isolation of active compounds from the extracts in combination with UPLC-MS and ¹H-NMR spectroscopy resulted in the identification of rosmarinic acid, luteolin-7-sulfate and diosmetin-7-sulfate or its isomer chrysoeriol-7-sulfate. All three compounds are nontoxic repellents, as they did not inhibit bacterial growth, but prevented bacterial settlement in a dose-dependent manner. Between 15.6 and 106.8 μg ml^?1 of rosmarinic acid were present on the eelgrass surface, enough for half maximal settlement inhibition of bacteria.     

Knowing when (not) to attempt ecological restoration

Here we argue that there are two important steps in the decision process to restore ecological system that are often ignored. First, consideration of restoration is in response to observed change in a system, but ecological systems can fluctuate widely in their normal dynamic. Thus, there is an imperative to interpret ecological change; shifts in community structure that represent “typical” fluctuations in a properly functioning ecosystem do not warrant restoration, while change associated with phase shift in the system may well demand restoration action. Second, where restoration effort is warranted, it needs to be determined whether management responses are likely to be successful within resource constraints. Where ecological change involves pronounced hysteresis, even massive effort may have little chance in effecting recovery to a preferred ecosystem state. Theory and models indicate that consideration of the characteristic length scales (CLSs) of ecological systems provides an unambiguous interpretation of ecological change, enabling differentiation of “typical” fluctuations from phase shift, and here we show that CLSs can be calculated for real communities from their species' dynamics, and that their behavior is as predicted from theory. We also show that for ecological systems where local interactions and forcings are well understood, validated simulation models can provide a ready means to identify hysteresis and estimate its magnitude. We conclude that there are useful tools available for ecologists to address the key questions of (1) whether restoration attempts are warranted in the first place and, if they are, (2) whether it is practical to pursue them.     

Multiple stressors threaten the imperiled coastal foundation species eelgrass (Zostera marina) in Chesapeake Bay,USA

Interactions among global change stressors and their effects at large scales are often proposed, but seldom evaluated. This situation is primarily due to lack of comprehensive, sufficiently long‐term, and spatially extensive datasets. Seagrasses, which provide nursery habitat, improve water quality, and constitute a globally important carbon sink, are among the most vulnerable habitats on the planet. Here, we unite 31 years of high‐resolution aerial monitoring and water quality data to elucidate the patterns and drivers of eelgrass (Zostera marina) abundance in Chesapeake Bay, USA, one of the largest and most valuable estuaries in the world, with an unparalleled history of regulatory efforts. We show that eelgrass area has declined 29% in total since 1991, with wide‐ranging and severe ecological and economic consequences. We go on to identify an interaction between decreasing water clarity and warming temperatures as the primary drivers of this trend. Declining clarity has gradually reduced eelgrass cover the past two decades, primarily in deeper beds where light is already limiting. In shallow beds, however, reduced visibility exacerbates the physiological stress of acute warming, leading to recent instances of decline approaching 80%. While degraded water quality has long been known to influence underwater grasses worldwide, we demonstrate a clear and rapidly emerging interaction with climate change. We highlight the urgent need to integrate a broader perspective into local water quality management, in the Chesapeake Bay and in the many other coastal systems facing similar stressors.     

Spaceflight induced changes in the human proteome

Introduction: Spaceflight is one of the most extreme conditions encountered by humans: Individuals are exposed to radiation, microgravity, hypodynamia, and will experience isolation. A better understanding of the molecular processes induced by these factors may allow us to develop personalized countermeasures to minimize risks to astronauts.

Areas covered: This review is a summary of literature searches from PubMed, NASA, Roskosmos and the authors’ research experiences and opinions. The review covers the available proteomic data on the effects of spaceflight factors on the human body, including both real space missions and ground-based model experiments.

Expert commentary: Overall, the authors believe that the present background, methodology and equipment improvements will enhance spaceflight safety and support accumulation of new knowledge on how organisms adapt to extreme conditions.     

以单床工作效率为核心的医院床位效能评价模型研究

目的 探讨单床工作效率指标在评价医院床位利用效率的应用及可行性,建立床位效能评价模型,为科学、有效的床位利用与评估提供依据。方法 提出单床工作效率概念,建立新的床位效能评价模型,分析2015年某院床位利用情况。结果 单床工作效率在评价床位利用效能方面优于其他指标,新的医院床位效能评价模型评价更为客观、准确。结论 单床工作效率为核心的医院床位效能评价模型具有更好的可比性和操作性,可在医院精细化管理中推广使用。     

Intertidal seagrass in Ireland: Pressures,WFD status and an assessment of trace element contamination in intertidal habitats using Zostera noltei

Intertidal seagrass has been selected as a Biological Quality Element for the assessment of ecological status under the Water Framework Directive. In Ireland, two species of seagrass, Zostera marina and Z. noltei occur in intertidal habitats. This study presents the first comprehensive assessment of the distribution and Water Framework Directive status of intertidal seagrass in the Republic of Ireland and Northern Ireland. Most of the areas assessed, using the Water Framework Directive-compliant assessment tool, have a status of HIGH or GOOD. Only two areas were found to have a status less than GOOD and in both, the cause for the decline was smothering by opportunistic foliose green macroalgae. Linear regression showed a relationship between pressure index scores and Ecological Quality Ratio, showing the relevance of the index as a metric of anthropogenic pressure. Trace element concentrations were examined in Z. noltei tissues and Trace Element Pollution Index values were calculated. The relationship between Trace Element contamination and Water Framework Directive status was examined but the results showed little correlation. However, a relationship between the pressure index and trace element contamination was obtained. This assessment provides the most comprehensive overview of intertidal seagrass beds in Ireland and establishes a strong baseline for ongoing monitoring and assessment under the Water Framework Directive. The data provide key information on the pressures affecting these valuable habitats which will assist in the development of measures to improve and protect our transitional and coastal waters.     

微生物发酵床养猪技术研究进展

微生物发酵床养猪模式是一种新型的低能耗、环保健康养殖方式。本文从微生物发酵床养猪技术原理、垫料的组成与管理技术、垫料微生物群落结构、对病原微生物的抑制作用、挥发性物质以及用后垫料资源化利用技术等方面综述了国内微生物发酵床养猪技术进展,分析了该技术推广应用中存在的问题,并提出构建微生物发酵床垫料资源化利用体系作为今后重点研究与发展方向。     

Occurrence of sulfated galactans in marine angiosperms: evolutionary implications

We report for the first time that marine angiosperms (seagrasses) possess sulfated polysaccharides, which are absent in terrestrial and freshwater plants. The structure of the sulfated polysaccharide from the seagrass Ruppia maritima was determined. It is a sulfated D-galactan composed of the following regular tetrasaccharide repeating unit: [3-beta-D-Gal-2(OSO3)-1-->4-alpha-D-Gal-1-->4-alpha-D-Gal-1-->3-beta-D-Gal-4(OSO3)-1-->]. Sulfated galactans have been described previously in red algae and in marine invertebrates (ascidians and sea urchins). The sulfated galactan from the marine angiosperm has an intermediate structure when compared with the polysaccharides from these two other groups of organisms. Like marine invertebrate galactan, it expresses a regular repeating unit with a homogenous sulfation pattern. However, seagrass galactan contains the D-enantiomer of galactose instead of the L-isomer found in marine invertebrates. Like red algae, the marine angiosperm polysaccharide contains both alpha and beta units of D-galactose; however, these units are not distributed in an alternating order, as in algal galactan. Sulfated galactan is localized in the plant cell walls, mostly in rhizomes and roots, indicative of a relationship with the absorption of nutrients and of a possible structural function. The occurrence of sulfated galactans in marine organisms may be the result of physiological adaptations, which are not correlated with phylogenetic proximity. We suggest that convergent adaptation, due to environment pressure, may explain the occurrence of sulfated galactans in many marine organisms.     

A novel system for continuous protein refolding and on-line capture by expanded bed adsorption

A novel two-step protein refolding strategy has been developed, where continuous renaturation-bydilution is followed by direct capture on an expanded bed adsorption (EBA) column. The performance of the overall process was tested on a N-terminally tagged version of human beta2-microglobulin (HAT-hbeta2m) both at analytical, small, and preparative scale. In a single scalable operation, extracted and denatured inclusion body proteins from Escherichia coli were continuously diluted into refolding buffer, using a short pipe reactor, allowing for a defined retention and refolding time, and then fed directly to an EBA column, where the protein was captured, washed, and finally eluted as soluble folded protein. Not only was the eluted protein in a correctly folded state, the purity of the HAThbeta2m was increased from 34% to 94%, and the product was concentrated sevenfold. The yield of the overall process was 45%, and the product loss was primarily a consequence of the refolding reaction rather than the EBA step. Full biological activity of HAT-hbeta2m was demonstrated after removal of the HAT-tag. In contrast to batch refolding, a continuous refolding strategy allows the conditions to be controlled and maintained throughout the process, irrespective of the batch size; i.e., it is readily scalable. Furthermore, the procedure is fast and tolerant toward aggregate formation, a common complication of in vitro protein refolding. In conclusion, this system represents a novel approach to small and preparative scale protein refolding, which should be applicable to many other proteins.