Increasing picocyanobacteria success in shelf waters contributes to long‐term food web degradation

Continental margins are disproportionally important for global primary production, fisheries and CO₂ uptake. However, across the Northeast Atlantic shelves, there has been an ongoing summertime decline of key biota—large diatoms, dinoflagellates and copepods—that traditionally fuel higher tropic levels such as fish, sea birds and marine mammals. Here, we combine multiple time series with in situ process studies to link these declines to summer nutrient stress and increasing proportions of picophytoplankton that can comprise up to 90% of the combined pico‐ and nanophytoplankton biomass in coastal areas. Among the pico‐fraction, it is the cyanobacterium Synechococcus that flourishes when iron and nitrogen resupply to surface waters are diminished. Our field data show how traits beyond small size give Synechococcus a competitive edge over pico‐ and nanoeukaryotes. Key is their ability to grow at low irradiances near the nutricline, which is aided by their superior light‐harvesting system and high affinity to iron. However, minute size and lack of essential biomolecules (e.g. omega‐3 polyunsaturated fatty acids and sterols) render Synechococcus poor primary producers to sustain shelf sea food webs efficiently. The combination of earlier spring blooms and lower summer food quantity and quality creates an increasing period of suboptimal feeding conditions for zooplankton at a time of year when their metabolic demand is highest. We suggest that this nutrition‐related mismatch has contributed to the widespread, ~50% decline in summer copepod abundance we observe over the last 60 years. With Synechococcus clades being prominent from the tropics to the Arctic and their abundances increasing worldwide, our study informs projections of future food web dynamics in coastal and shelf areas where droughts and stratification lead to increasing nutrient starvation of surface waters.     

Residence time and kinetic efficiency analysis of extracellular signal-regulated kinase 2 inhibitors

The RAS/RAF/MEK/ERK signal transduction cascade plays an important role in the regulation of critical cellular processes such as cell proliferation, migration, and differentiation. The up-regulation of this pathway can negatively affect cell homeostasis and is responsible for the development of various forms of cancer and inflammation processes. Therefore, there is a strong interest in pursuing drug programs targeting some of the enzymes involved in this pathway. In addition to the determination of K_i, K_d, IC₅₀, and/or EC_50, a more thorough kinetic analysis can provide useful information for the selection of the best lead series during the early stage of the drug discovery process. This study describes a medium-throughput fluorescent probe displacement assay for the rapid determination of the k_off constant, residence time, and kinetic efficiency for ERK (extracellular signal-regulated kinase) inhibitors. Using this method, we have identified several inhibitors that we have subjected to further kinetic analysis by comparing k_off constants determined for these time-dependent inhibitors using either the active or inactive form of ERK2.     

Evaluation of radiotagging techniques and their application to survival analysis of Red‐legged Partridge Alectoris rufa chicks

A better knowledge of chick survival rates is required to enable understanding of the population dynamics of gamebirds and to develop management measures to conserve their populations. The Red‐legged Partridge Alectoris rufa is a highly valued game species in Spain but its populations have declined in recent decades. A lack of appropriate monitoring methods has been a limitation in gaining information on the mortality of Red‐legged Partridge chicks. We developed methods for the effective radiotagging of chicks in captivity and applied these methods in the field in northern Spain to estimate survival during the first 5 months of life. The most effective method for radiotagging captive chicks between 3 and 8 days old involved gluing small tags directly to the skin in the interscapular space using cyanoacrylate adhesive. Backpack harness tags attached with elastic bands were the most effective method of radiotagging 4‐week‐old chicks. Predation was the main cause of chick mortality identified during the field experiments. Survival between hatching and 5 months of age was estimated to be 16–21%. The lowest survival rates occurred during the first 7 days of life (62–70% cumulative survival) and this period seems to be a major determinant in the life history of the species.     

Towards the natural classification of tectarioid ferns: Confirming the phylogenetic relationships of Pleocnemia and Pteridrys (eupolypods I)

The phylogenetic relationships of the two derived fern genera Pleocnemia and Pteridrys were considered ambiguous even with molecular evidence from previous studies. In the present study we determined the phylogenetic position based on five plastid DNA regions, namely atpA, atpB, rbcL, the rps4 + rps4–trnS intergenic spacer, and the trnL-F region, and an expanded taxonomic coverage including several accessions of each of the two genera. Our results showed that the monophyletic genus Pleocnemia belonged to the Dryopteridaceae and was not related to the Tectariaceae, as it had been in the past. Pleocnemia was found to be closely related to the bolbitidoid and lastreopsioid ferns. The monophyletic genus Pteridrys was found to be sister to a clade comprising Triplophyllum and Tectarias.l. Thus, the placement of this genus into Tectariaceae was confirmed. The sinus teeth, the unique similarity shared by Pleocnemia and Pteridrys, evolved independently in the two genera. Both genera appeared to have diverged from their closest extant relatives at least since the Eocene, whereas the crown group ages indicated radiation events in the Late Miocene for both genera.     

Tempo and mode of evolutionary radiation in Diabroticina beetles (genera Acalymma,Cerotoma, and Diabrotica)

Adaptive radiation is an aspect of evolutionary biology encompassing microevolution and macroevolution, for explaining the principles of lineage divergence. There are intrinsic as well as extrinsic factors that can be postulated to explain that adaptive radiation has taken place in specific lineages. The Diabroticina beetles are a prominent example of differential diversity that could be examined in detail to explain the diverse paradigms of adaptive radiation. Macroevolutionary analyses must present the differential diversity patterns in a chronological framework. The current study reviews the processes that shaped the differential diversity of some Diabroticina lineages (i.e. genera Acalymma, Cerotoma, and Diabrotica). These diversity patterns and the putative processes that produced them are discussed within a statistically reliable estimate of time. This was achieved by performing phylogenetic and coalescent analyses for 44 species of chrysomelid beetles. The data set encompassed a total of 2,718 nucleotide positions from three mitochondrial and two nuclear loci. Pharmacophagy, host plant coevolution, competitive exclusion, and geomorphological complexity are discussed as putative factors that might have influenced the observed diversity patterns. The coalescent analysis concluded that the main radiation within Diabroticina beetles occurred between middle Oligocene and middle Miocene. Therefore, the radiation observed in these beetles is not recent (i.e. post-Panamanian uplift, 4 Mya). Only a few speciation events in the genus Diabrotica might be the result of the Pleistocene climatic oscillations.     

The age of the crown group of passerine birds and its evolutionary significance – molecular calibrations versus the fossil record

Based on calibrations of molecular phylogenies and biogeographic considerations, it has been argued that the basal divergences of crown group Passeriformes occurred in the late Cretaceous, following the break-up of eastern Gondwana. Some implications of this hypothesis have, however, not yet been adequately addressed. In particular, a Cretaceous divergence of crown group passerines would imply an unprecedented evolutionary stasis for more than 80 million years in one of the most species-rich group of endothermic vertebrates. The temporal distribution and phylogenetic affinities of northern hemispheric fossils further conflicts with current hypotheses on the historical biogeography of passerines, and is in better concordance with a Cenozoic divergence of crown group Passeriformes.     

Phase-synchronization of daily motor activities can reveal differential circadian patterns

The aim of the study was to determine any alteration of the 24 h motor activity pattern of a bipolar patient in different mood states. Actigraphic records were collected on an outpatient basis for a total of 387 days. The daily actograms were synchronized in phase to the time of morning awakening before averaging, which significantly enhanced the structure of the averaged traces. The actograms were divided into three groups based on total daily count. The daily motor activity patterns of the low- and high-activity days have a different circadian pattern. We propose it may have a relevance to the different mood states. The phase-synchronization of the 24 h actograms to the patient's sleep-wake cycle, specifically to the time of awaking from the nighttime sleep, may help reveal differences in the daily temporal patterns of motor activity.     

土壤中棉花黄萎病菌SYBR Green Ⅰ荧光RT-PCR定量检测技术研究

为实现田间土壤棉花黄萎病菌的早期检测,建立了土壤中棉花黄萎病菌的SYBR Green I荧光定量PCR检测方法。以含342bp PCR扩增产物的阳性质粒为参考,构建了标准曲线,并对该曲线的特异性、敏感性、可重复性进行了评价。结果表明,该方法具有快速、特异性强、敏感度高等特点。检测范围在3.8×103-3.8×108copies/μL之间有良好的线性关系,相关系数R2为0.996,扩增效率为101.5%,灵敏度比常规PCR方法高102倍。     

Influence of oceanic factors on Anguilla anguilla (L.) over the twentieth century in coastal habitats of the Skagerrak,southern Norway

The European eel (Anguilla anguilla L.) is distributed in coastal and inland habitats all over Europe, but spawns in the Sargasso Sea and is thus affected by both continental and oceanic factors. Since the 1980s a steady decline has been observed in the recruitment of glass eels to freshwater and in total eel landings. The eel is considered as critically endangered on the International Union for the Conservation of Nature and Natural Resources Red List of species. The Skagerrak beach seine survey from Norway constitutes the longest fishery-independent dataset on yellow/silver eels (starting in 1904). The Skagerrak coastal region receives larvae born in the Sargasso Sea spawning areas that have followed the Gulf Stream/North Atlantic Drift before they penetrate far into the North Sea. The Skagerrak coastal time series is therefore particularly valuable for exploring the impacts of oceanic factors on fluctuations in eel recruitment abundance. Analyses showed that Sargasso Sea surface temperature was negatively correlated with eel abundance, with a lag of 12 years revealing a cyclic and detrimental effect of high temperatures on the newly hatched larvae. The North Atlantic Oscillation index and inflow of North Atlantic water into the North Sea were negatively correlated with eel abundance, with a lag of 11 years. Increased currents towards the North Atlantic during high North Atlantic Oscillation years may send larvae into the subpolar gyre before they are ready to metamorphose and settle, resulting in low recruitment in the northern part of the distribution area for these years. The Skagerrak time series was compared with glass eel recruitment to freshwater in the Netherlands (Den Oever glass eel time series), and similar patterns were found revealing a cycle linked to changes in oceanic factors affecting glass eel recruitment. The recent decline of eels in the Skagerrak also coincided with previously documented shifts in environmental conditions of the North Sea ecosystem.