Dissecting TRPV1: lessons to be learned?

The transient receptor potential channel TRPV1 is a polymodal nociceptor. It is primarily expressed in dorsal root ganglia and peripheral sensory nerve endings, and to a much lesser extent, in the central nervous system. It has also been implicated in the functional properties of e.g. urinary and bronchial epithelia. TRPV1 has long been under intensive investigation by the pharmaceutical industry as a candidate drug target especially for pain conditions. This review summarizes the current knowledge of the molecular determinants of TRPV1 channel activation by heat, protons and capsaicin. Newly discovered heat and proton activation sites within the pore domain are discussed as well as potential consequences for drug discovery. Polymodal TRPV1 antagonists were found to cause hyperthermia in a species-dependent manner in-vivo, hence the discovery of euthermic compounds with an appropriate modality selectivity profile will be crucial for TRPV1's future as a drug target.     

Can thallus color of red algae be used as an environmental indicator in shallow waters?

Red algae sometimes turn yellow, but few studies have been conducted on the yellowing of subtidal bed-forming species and on the relationship between the color and environmental factors. We examined the seasonal changes in thallus color of macroscopic subtidal red algae and nutrient levels as in shallow waters at two sites: Hirasawa (0 to 3 m in depth) and Okinoshima Island (0 to 6 m in depth), central Pacific coast of Japan from April 2011 to March 2012. Yellowed red algae were found at all depths of the two sites. At Hirasawa, the ratio of yellowed species among the red algae (yellowing ratio, YR) calculated with data on a total of 23 species (3 to 14 species month^?1) was high in months in which nitrate nitrogen (NO₃-N) was low (1.73 to 2.19 μmol L^?1); in months with higher NO₃-N (5.91 to 6.01 μmol L^?1), YR was 0 but exceptionally high in April probably because of the duration of fine days. At Okinoshima Island, YR calculated with data on a total of 40 species (3 to 22 species month^?1) was high from March to July (except May), in which NO₃-N was low (0.93 to 2.16 μmol L^?1), but low from October to February among the months with higher NO₃-N (4.56 to 5.62 μmol L^?1). Totally, YR was negatively correlated with nitrate concentrations and NO₃-N, which supports the possibility to use the value of YR as an indicator of nitrogen level although attention should also be paid to light conditions.     

Littoral macrophyte–periphyton complexes in two Hungarian shallow waters

Periphyton developing on the surfaces of emergent and submerged aquatic plants has a significant influence on water quality. The periphyton types that form on various plant species can be characterized by their mass values, the proportion of the present organic and inorganic fractions, as well as their chlorophyll-a contents. Studies on periphyton complexes constituting integrated biomonitoring systems are useful to gain essential long-term information about the performance of shallow water bodies. The filtering and settling effect of Phragmites and other aquatic plants, as well as their periphyton was examined and clearly observable in the water areas and non-flooded aquatic habitats belonging to the second phase of Kis-Balaton Protection System, as it was indicated by the mass values and ash contents. The periphyton forming on the aquatic vegetation that annually develops in Kisköre Reservoir and yields a considerable biomass has a critical part in influencing water quality. The only difference (p<0.05) was found in the ash content of the periphyton, being lower in Kis-Balaton (48.64 ± 2.29 S.E., %) and higher in Kisköre Reservoir (57.42 ± 2.54 S.E., %). This paper presents the dry mass of the periphyton, as well as its ash and chlorophyll-a content, and the results obtained on the composition of the alga species of the periphyton.

     

Dissecting TRPV1: Lessons to be learned?

The transient receptor potential channel TRPV1 is a polymodal nociceptor. It is primarily expressed in dorsal root ganglia and peripheral sensory nerve endings, and to a much lesser extent, in the central nervous system. It has also been implicated in the functional properties of e.g. urinary and bronchial epithelia. TRPV1 has long been under intensive investigation by the pharmaceutical industry as a candidate drug target especially for pain conditions. This review summarizes the current knowledge of the molecular determinants of TRPV1 channel activation by heat, protons and capsaicin. Newly discovered heat and proton activation sites within the pore domain are discussed as well as potential consequences for drug discovery. Polymodal TRPV1 antagonists were found to cause hyperthermia in a species-dependent manner in-vivo, hence the discovery of euthermic compounds with an appropriate modality selectivity profile will be crucial for TRPV1's future as a drug target.     

Cell wall integrity maintenance in plants: Lessons to be learned from yeast?

The plant cell wall is involved in different biological processes like cell morphogenesis and response to biotic/abiotic stress. Functional integrity of the wall is apparently being maintained during these processes by changing structure/composition and coordinating cell wall with cellular metabolism. In S.cerevisiae a well-characterized mechanism exists that is maintaining functional integrity of yeast the cell wall during similar processes. During the last years it has become obvious that plants have evolved a mechanism to monitor and maintain functional integrity of their cell walls. However, our understanding of the mechanism is rather limited. The available evidence suggests that similar signaling cascades may be involved and particular protein activities may be conserved between plants and yeast. Here we review the available evidence briefly and highlight similarities between yeast and plants that could help us to understand the mode of action of the signaling cascades maintaining plant cell wall integrity.     

The metabolic response to excitotoxicity – lessons from single-cell imaging

Journal of Bioenergetics and Biomembranes - Excitotoxicity is a pathological process implicated in neuronal death during ischaemia, traumatic brain injuries and neurodegenerative diseases....     

Can biotic resistance be utilized to reduce establishment rates of non-indigenous species in constructed waters?

Understanding the mechanisms that facilitate establishment of non-indigenous species is imperative for devising techniques to reduce invasion rates. Passively dispersing non-indigenous organisms, including zooplankton, seemingly invade constructed waters (e.g., ornamental ponds, dams and reservoirs) at faster rates than natural lakes. A common attribute of these invaded water bodies is their relatively young age, leading to the assertion that low biotic resistance may lead to their higher vulnerability. Our aim was to determine if seeding of young water bodies with sediments containing diapausing stages of native zooplankton could accelerate community development, leading to greater biotic resistance to the establishment of new species. Twenty outdoor tanks were filled with water (1,400 L) and nutrients added to attain eutrophic conditions. Ten treatment tanks had sediments added, sourced from local water bodies. In the remaining ten, sediments were autoclaved, and received zooplankton via natural dispersal only. In an initial 12 month monitoring period, species richness increased at a greater rate in the treatment tanks (at 12 months average standing richness per tank = 3.8, accumulated richness = 8.2) than control tanks (2.6 and 5.0, P < 0.05). Treatment tanks developed assemblages with greater proportions of species adapted to pelagic conditions, such as planktonic cladocerans and copepods, while control tanks generally comprised of smaller, littoral dwelling, rotifers. Analysis of similarities indicated community composition differed between the control and treatment groups at 12 months (P < 0.01). Two copepod, four rotifer and one cladoceran species were intentionally added to tanks at 12 months. In the 3 month post-introduction period, five of these species established populations in the control tanks, while only two species established in the treatment tanks. The calanoid copepod Skistodiaptomus pallidus, for example, a non-indigenous species confined to constructed waters in New Zealand, established exclusively in tanks where native calanoid copepod species were absent (primarily control tanks). Our study suggests that biotic resistance could play an important role in reducing the establishment rate of non-indigenous zooplankton. It also provides evidence that seeding constructed water bodies with sediments containing diapausing eggs of native species may provide an effective management tool to reduce establishment rates of non-indigenous zooplankton.     

Spatial and temporal diversity of small shallow waters in river Lužnice floodplain

To propose a concept of their mutual diversity, twenty-nine permanent shallow floodplain pools and oxbows in the river Lužnice floodplain were analysed for area, depth, shape, flooding, and shading by terrestrial vegetation, and sampled in all seasons for their water chemistry, phytoplankton composition and biomass, and zooplankton composition. The sites are regularly flooded, eutrophic, and often shaded by surrounding vegetation. Cryptophyceae, Chrysophyceae and Euglenophyceae dominated the phytoplankton, while Cyanophytes were rare. Within the rich zooplankton assemblage (63 species), cladocerans and rotifers dominated. Correlation matrices and multivariate analyses indicated that shaded and relatively deeper sites had lower oxygen saturation and higher concentrations of PO₄–P and NH₄–N. Shade and relative depth correlated negatively with phytoplankton biomass and number of phytoplankton taxa, and positively with Cryptophytes and large cladocerans—thus indicating poor mixing, poor light availability and low fish pressure on herbivores. Decomposition of leaf litter increased oxygen consumption, while shade from terrestrial vegetation restricted photosynthesis and decreased oxygen production. Larger sites were more species-rich in phytoplankton and supported Euglenophyceae, green algae and rotifers.     

Periphyton in running waters – long-term studies of natural variation

The objective of this study in River Atna, Norway, was to analyse the spatial and temporal variation in species composition and diversity of the periphyton community in a pristine sub-alpine / boreal watercourse. The variations in the biotic parameters were related to selected environmental factors. We addressed epilithic algae and species living epiphytic on epilithic algae and submerged bryophytes. The sampling sites were located in the alpine, northern boreal, and mid boreal biomes. There was considerable spatial variation in species composition and diversity. This variation showed close correlation with natural gradients in water temperature and nutrient concentration. Three or four periphyton community categories could be distinguished in terms of species composition, diversity, and environmental variables. At high altitudes (1150–740 m a.s.l.) in cold water temperatures and extremely low nutrient contents, there was very low species diversity, only including algae known from ultra oligothrophic cold waters, e.g. Scytonematopsis starmachii (cyanobacteria) and Klebshormidium rivulare (green algae). The second category, at medium altitudes (701–522 m a.s.l.), was characterised by somewhat higher water temperatures and nutrient contents, and the species diversity was higher. This category included algae known from somewhat richer waters, e.g. Stigonema mamillosum (cyanobacteria) and Zygnema spp.(green algae). The third category was located at approx. 522 m a.s.l., had low water temperatures, relatively high alkalinity, and was characterised by Tolypothrix distorta (cyanobacteria) and Ulothrix zonata (green algae). A possible fourth category was found in the lower part of the river (350 m a.s.l.), where periphyton was distinguished by high diversity. At the individual sampling localities, species diversity showed strong seasonal variation, but otherwise high temporal stability. Over the 12 years of observations, there was only a weak temporal trend; towards species initially occurring only at low altitudes and high nutrient content. The combination of high temporal stability and high spatial variability, correlating closely with environmental gradients, is the main reason why periphyton observations have become an important constituent in water quality assessment.     

How to increase juvenile shrimps in mangrove waters?

The distribution, density and species composition of juvenile shrimps were studied in three mangrove zones of Pichavaram, situated on the southeast coast of India. Nine species of shrimps dominated with Metapenaeus monoceros, M. brevicornis and Penaeus indicus were recorded. This shrimp resource was higher in mangrove-lined waters than that in neritic waters. This field observation was experimentally proved using litter bags. The average catch around the litter bags was 0.80 individuals day^–1 for Rhizophora leaves, 1.6 ind. day^–1 for Avicennia leaves and 0.16 ind. day^–1 in control. In general, abundance of juvenile shrimps was the highest around the leaves that were decomposed for 40 days and colonized with high counts of nitrogen-fixing azotobacters. Finally, a vegetation trap technique using mangrove leaves has been proposed for efficient schooling of juvenile shrimps. There was about 3-fold increase in number of shrimp juveniles around the trap than at control waters.     

Bioleaching in brackish waters—effect of chloride ions on the acidophile population and proteomes of model species

High concentrations of chloride ions inhibit the growth of acidophilic microorganisms used in biomining, a problem particularly relevant to Western Australian and Chilean biomining operations. Despite this, little is known about the mechanisms acidophiles adopt in order to tolerate high chloride ion concentrations. This study aimed to investigate the impact of increasing concentrations of chloride ions on the population dynamics of a mixed culture during pyrite bioleaching and apply proteomics to elucidate how two species from this mixed culture alter their proteomes under chloride stress. A mixture consisting of well-known biomining microorganisms and an enrichment culture obtained from an acidic saline drain were tested for their ability to bioleach pyrite in the presence of 0, 3.5, 7, and 20 g L⁻¹ NaCl. Microorganisms from the enrichment culture were found to out-compete the known biomining microorganisms, independent of the chloride ion concentration. The proteomes of the Gram-positive acidophile Acidimicrobium ferrooxidans and the Gram-negative acidophile Acidithiobacillus caldus grown in the presence or absence of chloride ions were investigated. Analysis of differential expression showed that acidophilic microorganisms adopted several changes in their proteomes in the presence of chloride ions, suggesting the following strategies to combat the NaCl stress: adaptation of the cell membrane, the accumulation of amino acids possibly as a form of osmoprotectant, and the expression of a YceI family protein involved in acid and osmotic-related stress.     

Don't forget to be picky – selective autophagy of protein aggregates in neurodegenerative diseases

The homeostasis of cells depends on the selective degradation of damaged or superfluous cellular components. Autophagy is the major pathway that recognizes such components, sequesters them in de novo formed autophagosomes and delivers them to lysosomes for degradation. The recognition of specific cargo and the biogenesis of autophagosomes involve a dedicated machinery of autophagy related (ATG) proteins. Intense research over the past decades has revealed insights into the function of autophagy proteins and mechanisms that govern cargo recognition. Other aspects including the molecular mechanisms involved in the onset of human diseases are less well understood. However, autophagic dysfunctions, caused by age related decline in autophagy or mutations in ATG proteins, are directly related to a large number of human pathologies including neurodegenerative disorders. Here, we review most recent discoveries and breakthroughs in selective autophagy and its relationship to neurodegeneration.     

Correction to: Out‑of‑field effects: lessons learned from partial body exposure

Radiation and Environmental Biophysics -     

Recent trends in the abundance of plaice Pleuronectes platessa and cod Gadus morhua in shallow coastal waters of the Northeastern Atlantic continental shelf – a review

Shallow, near-shore water habitats on the continental shelf of the Northeast Atlantic have been productive fishing areas in the past. Here, we review the present knowledge about (i) recent trends in the abundance of plaice and cod in these habitats and (ii) hypotheses regarding the factors responsible for any trends. At present, only a few studies exist on the trends of abundance of plaice or cod, namely from the Bay of Biscay, the North Sea and the Skagerrak/Kattegat. They suggest a declining abundance in coastal, shallow areas and – at least for plaice – a latitudinal gradient with an erosion of the southern distribution boundary in the Bay of Biscay and deepening of stocks in the North Sea. In contrast, no trend in shallow water abundance of plaice similar to a decline in deep-water stocks during the 1970s and their slow recovery during the 2000s is apparent in the Skagerrak/Kattegat. Although shallow habitats fundamentally differ from deeper areas by the prevalence of juvenile stages, the declining trends coincide with decreasing abundance/landings and spatial stock relocations in the deeper areas. Whether this indicates a common trend pointing at connectivity between shallow and deep water remains open. Fundamental differences exist in the suggested causes of the trends in different geographical areas. High fishing pressure together with low local recruitment apparently prevents the recovery of overexploited plaice and cod stocks in the Skagerrak/Kattegat. In contrast, the responses of juveniles and adult fish to increasing seawater temperature are the main hypotheses for changes in distribution and abundance of both fish species in the North Sea/Bay of Biscay. However, temperature alone cannot explain the observed decline of fish in coastal areas, and the causes may be more complex, involving nutrient loading, primary productivity or food availability, although at present, knowledge of these factors is insufficient.     

Can the EU agri-environmental aid program be extended into the coastal zone to combat eutrophication?

Eutrophication of coastal waters is a serious environmental problem with high costs for society globally. This is a development which demands immediate environmental action along many coastal sites. Since the 1980s, mussel farming has been recognized by Swedish environmental authorities as a possible measure to improve coastal water quality. Concepts and management strategies on how to increase mussel farming and thus combat coastal marine eutrophication has recently been developed in Sweden. The main principle of this development has been the implementation of nutrient trading as a management tool. This imposes demands on those who emit the pollution through the establishment of emission quotas, which are traded and bought by the emitter. The seller is a nutrient harvesting enterprise, e.g., a mussel farmer. This principle is particularly straightforward when the nutrients are discharged from a point source. When examining the nutrient supply from all diffuse sources, the situation is more complex. However, since the major part of the nutrient supply to coastal waters in many areas of Europe has its origin in agricultural operations, we suggest that the EU agro-environmental aid program could be extended into the coastal zone in order to combat eutrophication. In practice, this should involve support paid to mussel farming enterprises through their harvest of mussels (and thus their harvest of nutrients) in the same way as support is paid to agricultural farmers for operations that reduce nutrient leakage from their farmland. This is a simple, cost-effective and straightforward way of improving coastal water quality at many coastal sites that will, at the same time, provide coastal jobs. However, this eutrophication combat method depends on the EU agro-environmental aid program being extended beyond the shoreline. Guest editors: J. H. Andersen & D. J. Conley Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark