Meiobenthic distribution and nematode community structure in five European estuaries

Meiofauna from the intertidal zone of five European estuaries (Ems, Westerschelde, Somme, Gironde, Tagus) was investigated. Samples represented a cross section of various benthic habitats from near-freshwater to marine, from pure silts to fine-sandy bottoms. The meiobenthic community comprised everywhere a fauna strongly dominated by nematodes, with meiobenthic density increasing with increasing salinity. The Ems differed from the other estuaries due to the presence of a well developed community of Copepods, Gastrotrichs, large Ciliates and/or soft-shelled Foraminiferans in some sites. The Westerschelde stood out due to the near-absence of harpacticoid copepods and, as in the Tagus, the lower meiobenthic densities in the marine part of the estuary. For nematode community analysis, we also included data from the Tamar which were obtained from the literature (Warwick &; Gee, 1984). This resulted in the enumeration of 220 species, belonging to 102 genera, each with a characteristic distribution along the salinity, sedimentary and latitudinal gradients. Using the multivariate technique CANOCO, a zonation along these different physicochemical determinants was observed as well although salinity and sediment characteristic (scale of hundreds of meters to kilometers) proved to be more important in explaining community structure than latitudinal differences (scale of hundreds of kilometers). Nematode diversity was nearly entirely determined on the genus level and was positively related to salinity. Deviations from this general trend in the Gironde and the Tamar were attributed to sedimentary characteristics or to low macrobenthic predation. The presence of a typical opportunistic colonizing nematode species Pareurodiplogaster pararmatus in the low-salinity region of the Gironde could indicate (organic?) pollution or disturbance of the intertidal mud-flats.     

Mass spectral characterization of two onion constituents with prostaglandin E-like activity as lipoxygenase metabolites of linoleic acid

Onions ($\text{Allium cepa}$ have been used in folk medicine for the treatment of hypertension and gastrointestinal ulcers, which are cases where the administration of prostaglandins is considered. Using bioassay guided fractionation and gas chromatography/mass spectrometry (GC/MS) we have isolated two biologically active fractions with PGE-like properties and have characterized these products as lipoxygenase metabolites of linoleic acid.For the isolation of the active principles, onion bulbs were homogenized in phosphate buffer and the PGE-like products were isolated using Amberlite XAD-2 absorption, silicic acid column chromatography and silicagel thin layer chromatography. The PGE-like activity was estimated in a cascade superfusion system in which the isolated rabbit coeliac artery, the rabbit mesenteric artery and the rat fundus were used as assay organs.For the GC/MS characterization, various types of volatile derivatives were prepared in order to facilitate the structure elucidation. Derivatization included hydrogenation, methyl ester formation, n-butyl boronate formation and trimethylsilylation. The active fractions yielded identical electron-impact mass spectra, indicating that they are stereoisomeric, and each fraction was identified as a mixture of two positional isomers, i.e. of 9,12,13-trihydroxy-10-octadecenoic and of 9,10,13-trihydroxy-11-octadecenoic acid. With regard to the structure elucidation of the latter isomers, the mixed hydrogenated, n-butyl boronate, methyl ester, TMS-ether derivatives were shown to be of particular value for the determination of the vicinal diol function.The isomeric trihydroxylated octadecenoic acids have been described for the first time as metabolites of linoleic acid in wheat flour incubates. In this system, the trihydroxylated octadecenoic acids were shown to be formed through a sequence of three reactions, including an initial 9- or 13-lipoxygenation yielding hydroperoxy octadecadienoic acids, followed by rearrangement into unstable allylic epoxy hydroxy octadecenoic acids, which in turn are hydrolyzed to trihydroxy octadecenoic acids. Furthermore, structurally related trihydroxy octadecadienoic acids have also recently been isolated from a plant source, more specifically from the roots of $\text{Bryonia Alba}$, which are used for the same medicinal purposes as onion bulbs.     

The systematic relationships ofAegialitis (Plumbaginaceae) as revealed by pollen morphology

Light and first SEM observations on the pollen ofAegialitis indicate that the two species of the genus are clearly distinguishable from all other genera of the tribeStaticeae to whichAegialitis presently is relegated. Intraspecific exine or aperture dimorphism which appears frequently in this tribe, is not recorded in this genus.A. annulata andA. rotundifolia have distinct monomorphic pollen and show a great resemblance in exine features with the tribePlumbagineae, particularly species ofPlumbago. Considering these and other features, separate subtribal status forAegialitis within thePlumbagineae is proposed.     

Architecture of the T-system in helical paramyosin muscles of an annelid (Branchiobdella)

Tannic acid impregnation has revealed the existence of a T-system in the helical fibers of Branchiobdella pentodonta (Annelida, Clitellata). T-tubules are L-shaped inside the fiber, within the plane of the I-band: after a short horizontal tract they run longitudinally for a long tract keeping contact with many sarcoplasmic reticulum cisternae and forming dyads. The presence of a T-system in this annelid, the only one demonstrated up to now in annelids, is to be ascribed to the thickness of the contractile layer of those fibers.     

Nucleotide sequences of the trpG regions of Escherichia coli,Shigella dysenteriae,Salmonella typhimurium and Serratia marcescens

The nucleotide sequences of Serratia marcescens trpG and the corresponding regions of Escherichia coli, Shigella dysenteriae and Salmonella typhimurium trpD have been determined. Analysis of the nucleotide sequence divergence suggests the following evolutionary relationships: Serratia-[Salmonella, (Escherichia, Shigella)]. Partial reconstruction of ancestral nucleotide sequences and subsequent analysis of nucleotide substitutions show that the majority of nucleotide substitutions in the evolution of trp(G)D are transitions that result in a reduction of G + C content. Since most of the nucleotide substitutions are in the third position of codons, bias in synonymous codon usage also reflects G + C content. The trpE-trp(G)D junction in the four organisms is characterized by overlapping translation termination and initiation codons. The relative positions of trpE and trp(G)D thus became fixed in evolution before the fusion of trpG and trpD. Nucleotide sequences representing the fusion of trpG and trpD in Escherichia, Shigella and Salmonella are not more nor less divergent than other portions of the trp(G)D coding sequences.     

An improved breeding method for solitarious locusts

In order to unravel the physiological, endocrine, and behavioral differences between gregarious and solitarious forms of the desert locust, Schistocerca gregaria (Forsk.) (Orthoptera, Acrididae), a constant supply of rather large numbers of solitary individuals has to be guaranteed. This represents a bottleneck, mainly because of the intensity of the labor involved and limited laboratory accommodation. The method we describe here substantially reduces the space and manpower needed. The survival rate we obtained in the solitarised population was relatively high, reaching about 55%. The optimal rearing temperature proved to be 32–36 °C. Cabbage leaves and oat flakes sufficed for feeding all year round. Special racks have been designed that enable high density stacking and easy handling. The solitarisation process was monitored over ten consecutive generations. Changes in morphometrics, eye stripes, color, and behavior were recorded, of which only morphometrics, temperature related development, and mortality are discussed. A shift towards the solitarious phase was recorded, with clear differences between gregarious, 1^st generation and 7^th to 10^th generation solitarious locusts.     

A combined CaMKII inhibition and mineralocorticoid receptor antagonism via eplerenone inhibits functional deterioration in chronic pressure overloaded mice

In the diseased and remodelled heart, increased activity and expression of Ca^2+/calmodulin‐dependent protein kinase II (CaMKII), an excess of fibrosis, and a decreased electrical coupling and cellular excitability leads to disturbed calcium homeostasis and tissue integrity. This subsequently leads to increased arrhythmia vulnerability and contractile dysfunction. Here, we investigated the combination of CaMKII inhibition (using genetically modified mice expressing the autocamtide‐3‐related‐peptide (AC3I)) together with eplerenone treatment (AC3I‐Epler) to prevent electrophysiological remodelling, fibrosis and subsequent functional deterioration in a mouse model of chronic pressure overload. We compared AC3I‐Epler mice with mice only subjected to mineralocorticoid receptor (MR) antagonism (WT‐Epler) and mice with only CaMKII inhibition (AC3I‐No). Our data show that a combined CaMKII inhibition together with MR antagonism mitigates contractile deterioration as was manifested by a preservation of ejection fraction, fractional shortening, global longitudinal strain, peak strain and contractile synchronicity. Furthermore, patchy fibrosis formation was reduced, potentially via inhibition of pro‐fibrotic TGF‐β/SMAD3 signalling, which related to a better global contractile performance and a slightly depressed incidence of arrhythmias. Furthermore, the level of patchy fibrosis appeared significantly correlated to eplerenone dose. The addition of eplerenone to CaMKII inhibition potentiates the effects of CaMKII inhibition on pro‐fibrotic pathways. As a result of the applied strategy, limiting patchy fibrosis adheres to a higher synchronicity of contraction and an overall better contractile performance which fits with a tempered arrhythmogenesis.     

Innate immunity orchestrates the mobilization and homing of hematopoietic stem/progenitor cells by engaging purinergic signaling—an update

Purinergic Signalling - Bone marrow (BM) as an active hematopoietic organ is highly sensitive to changes in body microenvironments and responds to external physical stimuli from the surrounding...     

Soil amendment interacts with invasive grass and drought to uniquely influence aboveground versus belowground biomass in aridland restoration

Water‐holding soil amendments such as super‐absorbent polymer (SAP) may improve native species establishment in restoration but may also interact with precipitation or invasive species such as Bromus tectorum L. (cheatgrass or downy brome) to influence revegetation outcomes. We implemented an experiment at two sites in Colorado, U.S.A., in which we investigated the interactions of drought (66% reduction of ambient rainfall), B. tectorum seed addition (BRTE, 465 seeds/m²), and SAP soil amendment (25 g/m²) on initial plant establishment and 3‐year aboveground and belowground biomass and allocation. At one site, SAP resulted in higher native seeded species establishment but only with ambient precipitation. However, by the third year, we detected no SAP effects on native seeded species biomass. Treatments interacted to influence aboveground and belowground biomass and allocation differently. At one site, a SAP × precipitation interaction resulted in lower belowground biomass in plots with SAP and drought (61.7 ± 7.3 g/m²) than plots with drought alone (91.6 ± 18.1 g/m²). At the other site, a SAP × BRTE interaction resulted in higher belowground biomass in plots with SAP and BRTE (56.6 ± 11.2 g/m²) than BRTE alone (35.0 ± 3.7 g/m²). These patterns were not reflected in aboveground biomass. SAP should be used with caution in aridland restoration because initial positive effects may not translate to long‐term benefits, SAP may uniquely influence aboveground versus belowground biomass, and SAP can interact with environmental variables to impact developing plant communities in positive and negative ways.     

The phylogenetic range of bacterial and viral pathogens of vertebrates

Many major human pathogens are multihost pathogens, able to infect other vertebrate species. Describing the general patterns of host–pathogen associations across pathogen taxa is therefore important to understand risk factors for human disease emergence. However, there is a lack of comprehensive curated databases for this purpose, with most previous efforts focusing on viruses. Here, we report the largest manually compiled host–pathogen association database, covering 2,595 bacteria and viruses infecting 2,656 vertebrate hosts. We also build a tree for host species using nine mitochondrial genes, giving a quantitative measure of the phylogenetic similarity of hosts. We find that the majority of bacteria and viruses are specialists infecting only a single host species, with bacteria having a significantly higher proportion of specialists compared to viruses. Conversely, multihost viruses have a more restricted host range than multihost bacteria. We perform multiple analyses of factors associated with pathogen richness per host species and the pathogen traits associated with greater host range and zoonotic potential. We show that factors previously identified as important for zoonotic potential in viruses—such as phylogenetic range, research effort, and being vector‐borne—are also predictive in bacteria. We find that the fraction of pathogens shared between two hosts decreases with the phylogenetic distance between them. Our results suggest that host phylogenetic similarity is the primary factor for host‐switching in pathogens.