Xylem acoustic emissions and water relations of Calluna vulgaris L. at two climatological regions of Britain

The acoustic emission rate (as a result of xylem cavitation), stem water content, stomatal conductance, and leaf water potential of heather (Calluna vulgaris L. Hull) were compared over a period of 18 months at two contrasting sites in Britain. The sites were Thursely Common in south-east England, and Flanders Moss in central Scotland (average rainfall of 600 mm per year and 1500 mm per year, respectively). In the first year of study (1992) the natural difference between the sites was amplified by a severe drought affecting south-east England. The relative water content of the xylem (RWC) did not differ between the sites, and did not fluctuate seasonally, despite the drought at Thursely. Acoustic emissions were detected at both sites, but the incidence was low. The same range of foliage water potential and stomatal conductance was found at both sites. The leaf area to sapwood area ratio at the dry site was half that at the wet site, and it is suggested that this adjustment of the transpiring area relative to the water conducting area facilitates the close physiological state of the plants at the two sites. The possible occurrence of aerial refilling and freezing induced xylem cavitation is also discussed.     

Diversity and dynamics of the DNA and cDNA-derived bacterial compost communities throughout the <Emphasis Type="Italic">Agaricus bisporus</Emphasis> mushroom cropping process

The cultivation of Agaricus bisporus involves the conversion of agricultural materials via fermentation into utilisable simple sugars as a nutrient source for the fungal crop during mushroom cropping. However, little is currently known about the role of the bacterial community contributing to the fermentation process. In this investigation we characterised the composition and dynamics of the DNA and cDNA-derived bacterial populations throughout a commercial mushroom cropping process using MiSeq sequencing. Both methods indicated substantial changes in the bacterial community structure after the first flush of the mushroom crop. However, differences were observed between the composition of the bacterial community determined by each of the two methods. The cDNA-derived community indicated that thermotolerant genera with known sulphur-reducing characteristics were highly active up to the first flush. Activity of the phyla Actinobacteria and Firmicutes was observed to increase as fermentation progressed, indicating that the members of these phyla played prominent roles in the conversion of wheat straw into utilisable sugars. The cDNA-derived community comprised genera with roles in the nitrification process that became highly active at post flush 1. Subsequent chemical analysis of extractable nitrate indicated that substantial nitrification occurred up until the termination of the cropping process. This study has demonstrated that a highly dynamic bacterial community is present throughout the mushroom cropping process.     

The development of an intermediate‐duration tag to characterize the diving behavior of large whales

The development of high‐resolution archival tag technologies has revolutionized our understanding of diving behavior in marine taxa such as sharks, turtles, and seals during their wide‐ranging movements. However, similar applications for large whales have lagged behind due to the difficulty of keeping tags on the animals for extended periods of time. Here, we present a novel configuration of a transdermally attached biologging device called the Advanced Dive Behavior (ADB) tag. The ADB tag contains sensors that record hydrostatic pressure, three‐axis accelerometers, magnetometers, water temperature, and light level, all sampled at 1 Hz. The ADB tag also collects Fastloc GPS locations and can send dive summary data through Service Argos, while staying attached to a whale for typical periods of 3–7 weeks before releasing for recovery and subsequent data download. ADB tags were deployed on sperm whales (Physeter macrocephalus; N = 46), blue whales (Balaenoptera musculus; N = 8), and fin whales (B. physalus; N = 5) from 2007 to 2015, resulting in attachment durations from 0 to 49.6 days, and recording 31 to 2,539 GPS locations and 27 to 2,918 dives per deployment. Archived dive profiles matched well with published dive shapes of each species from short‐term records. For blue and fin whales, feeding lunges were detected using peaks in accelerometer data and matched corresponding vertical excursions in the depth record. In sperm whales, rapid orientation changes in the accelerometer data, often during the bottom phase of dives, were likely related to prey pursuit, representing a relative measure of foraging effort. Sperm whales were documented repeatedly diving to, and likely foraging along, the seafloor. Data from the temperature sensor described the vertical structure of the water column in all three species, extending from the surface to depths >1,600 m. In addition to providing information needed to construct multiweek time budgets, the ADB tag is well suited to studying the effects of anthropogenic sound on whales by allowing for pre‐ and post‐exposure monitoring of the whale's dive behavior. This tag begins to bridge the gap between existing long‐duration but low‐data throughput tags, and short‐duration, high‐resolution data loggers.     

Protein aggregation in the brain: the molecular basis for Alzheimer's and Parkinson's diseases

Developing effective treatments for neurodegenerative diseases is one of the greatest medical challenges of the 21st century. Although many of these clinical entities have been recognized for more than a hundred years, it is only during the past twenty years that the molecular events that precipitate disease have begun to be understood. Protein aggregation is a common feature of many neurodegenerative diseases, and it is assumed that the aggregation process plays a central role in pathogenesis. In this process, one molecule (monomer) of a soluble protein interacts with other monomers of the same protein to form dimers, oligomers, and polymers. Conformation changes in three-dimensional structure of the protein, especially the formation of beta-strands, often accompany the process. Eventually, as the size of the aggregates increases, they may precipitate as insoluble amyloid fibrils, in which the structure is stabilized by the beta-strands interacting within a beta-sheet. In this review, we discuss this theme as it relates to the two most common neurodegenerative conditions-Alzheimer's and Parkinson's diseases.     

RIG-I mediates the co-induction of tumor necrosis factor and type I interferon elicited by myxoma virus in primary human macrophages

The sensing of pathogen infection and subsequent triggering of innate immunity are key to controlling zoonotic infections. Myxoma virus (MV) is a cytoplasmic DNA poxvirus that in nature infects only rabbits. Our previous studies have shown that MV infection of primary mouse cells is restricted by virus-induced type I interferon (IFN). However, little is known about the innate sensor(s) involved in activating signaling pathways leading to cellular defense responses in primary human immune cells. Here, we show that the complete restriction of MV infection in the primary human fibroblasts requires both tumor necrosis factor (TNF) and type I IFN. We also demonstrate that MV infection of primary human macrophages (pHMs) activates the cytoplasmic RNA sensor called retinoic acid inducible gene I (RIG-I), which coordinately induces the production of both TNF and type I IFN. Of note, RIG-I sensing of MV infection in pHMs initiates a sustained TNF induction through the sequential involvement of the downstream IFN-regulatory factors 3 and 7 (IRF3 and IRF7). Thus, RIG-I-mediated co-induction of TNF and type I IFN by virus-infected pHMs represents a novel innate defense mechanism to restrict viral infection in human cells. These results also reveal a new regulatory mechanism for TNF induction following viral infection.     

PTP1B inhibitors: synthesis and evaluation of difluoro-methylenephosphonate bioisosteres on a sulfonamide scaffold

We have synthesized and evaluated a series of triaryl sulfonamide-based PTP1B inhibitors in which a difluoro-methylenephosphonate group of a potent lead has been replaced by potential bioisosteric replacements. Several mono- or di-charged compounds (8a, 8b, and 15a) were shown exhibit inhibitory activity in the low micromolar range, demonstrating the feasibility of using this approach in identifying non-phosphonate pTyr mimetics in a small molecular scaffold. These results also provide a useful indication of the relative effectiveness of these pTyr mimetics.     

Rhodanine derivatives as novel inhibitors of PDE4

The discovery, synthesis and in vitro activity of a novel series of rhodanine based phosphodiesterase-4 (PDE4) inhibitors is described. Structure-activity relationship studies directed toward improving potency led to the development of submicromolar inhibitors 2n and 3i (IC(50)=0.89 & 0.74 microM). The replacement of rhodanine with structurally related heterocycles was also investigated and led to the synthesis of pseudothiohydantoin 7 (IC(50)=0.31 microM).     

Assessment of eutrophication pressure on lakes using littoral invertebrates

Until the E.U. Water Framework Directive listed benthic invertebrates as a biotic element to be used for ecological classification of lakes, techniques for the assessment of the response of littoral invertebrates to anthropogenic pressures were extremely limited compared with those of rivers and lake profundal zones. We describe here the development of an ecological classification model based on changes of littoral invertebrate assemblages across a gradient of eutrophication, which is the most widespread anthropogenic pressure on lakes across Europe. The model comprises three derived parameters, two of which were developed from taxon-specific optima along a total phosphorus gradient calculated using canonical correspondence analysis, and the third based on invertebrate abundance. Combining the parameter metrics, we can estimate the ecological quality ratio (EQR), relative to those from paleolimnologically-confirmed reference lakes. The model was tested using independent samples collected from both hard and soft substrata and across two seasons from 45 lakes, comprising three alkalinity groups (n = 15 in each), and across gradients in water column total phosphorus concentrations. For hard substrata, EQRs were related consistently and highly significantly to water column concentrations of total phosphorus, accounting for the majority of the variance in every alkalinity group. For samples taken from soft substrata, a significant relationship was found only for high alkalinity lakes, accounting for a moderate proportion of the variability in water column total phosphorus concentrations. Our results compare highly favourably with those from other aquatic ecological assessment methods, irrespective of the faunal or floral group upon which they are based, demonstrating that littoral invertebrate assemblages can provide a statistically robust prediction of nutrient status when samples are collected from hard substrata. While the method was developed specifically to assess nutrient pressures on littoral invertebrates, many lakes are subject to multiple pressures. The development of classification models that incorporate multiple pressures presents a particularly significant challenge for the implementation of the Water Framework Directive, requiring both reliable identification of minimally-impacted reference states and incorporation of pressures that are unlikely to interact in predictable ways.