ALBERT

Description: Currently, two pathogenic pathways describe the role of obesity in osteoarthritis (OA); one through biomechanical stress, and the other by the contribution of systemic inflammation. The aim of this study was t...

Description: In this study, a coating from electrospun silk fibroin was performed with the aim to modify the surface of breast implants. We evaluated the effect of fibroin on polymeric matrices of poly (ethylene oxide) (PEO) to enhance cell viability, adhesion, and proliferation of HaCaT human keratinocytes to enhance the healing process on breast prosthesis implantation. We electrospun six blends of fibroin and PEO at different concentrations. These scaffolds were characterized by scanning electron microscopy, contact angle measurements, ATR-FTIR spectroscopy, and X-ray diffraction. We obtained diverse network conformations at different combinations to examine the regulation of cell adhesion and proliferation by modifying the microstructure of the matrix to be applied as a potential scaffold for coating breast implants. The key contribution of this work is the solution it provides to enhance the healing process on prosthesis implantation considering that the use of these PEO–fibroin scaffolds reduced (p 〈 0.05) the amount of pyknotic nuclei. Therefore, viability of HaCaT human keratinocytes on PEO–fibroin matrices was significantly improved (p 〈 0.001). These findings provide a rational strategy to coat breast implants improving biocompatibility.

Description: RESEARCH Open Access An atlas of larval organogenesis in the European shore crab Carcinus maenas L. (Decapoda, Brachyura, Portunidae) Franziska Spitzner 1,2 , Rebecca Meth 1,2 , Christina Krüger 1 , Emanuel Nischik 1 , Stefan Eiler 1,3 , Andy Sombke 1 , Gabriela Torres 2 † and Steffen Harzsch 1* † Abstract Background: The life history stages of brachyuran crustaceans include pelagic larvae of the Zoea type which grow by a series of moults from one instar to the next. Zoeae actively feed and possess a wide range of organ systems necessary for autonomously developing in the plankton. They also display a rich behavioural repertoire that allows for responses to variations in environmental key factors such as light, hydrostatic pressure, tidal currents, and temperature. Brachyuran larvae have served as distinguished models in the field of Ecological Developmental Biology fostering our understanding of diverse ecophysiological aspects such as phenotypic plasticity, carry-over effects on life-history traits, and adaptive mechanisms that enhance tolerance to fluctuations in environmental abiotic factors. In order to link such studies to the level of tissues and organs, this report analyses the internal anatomy of laboratory-reared larvae of the European shore crab Carcinus maenas . This species has a native distribution extending across most European waters and has attracted attention because it has invaded five temperate geographic regions outside of its native range and therefore can serve as a model to analyse thermal tolerance of species affected by rising sea temperatures as an effect of climate change. Results: Here, we used X-ray micro-computed tomography combined with 3D reconstruction to describe organogenesis in brachyuran larvae. We provide a detailed atlas of the larval internal organization to complement existing descriptions of its external morphology. In a multimethodological approach, we also used cuticular autofluorescence and classical histology to analyse the anatomy of selected organ systems. Conclusions: Much of our fascination for the anatomy of brachyuran larvae stems from the opportunity to observe a complex organism on a single microscopic slide and the realization that the entire decapod crustacean bauplan unfolds from organ anlagen compressed into a miniature organism in the sub-millimetre range. The combination of imaging techniques used in the present study provides novel insights into the bewildering diversity of organ systems that brachyuran larvae possess. Our analysis may serve as a basis for future studies bridging the fields of evolutionary developmental biology and ecological developmental biology

Description: We discuss several forms of developmental plasticity exhibited by marine crabs, in the context of ecological developmental biology (EcoDevo), and seek to motivate research in EcoDevo by addressing some key questions of the field. We summarise the diversity of plastic developmental responses exhibited during crab development, identify gaps in knowledge and highlight the importance of EcoDevo research in the light of current climate change. Marine crabs show a suite of plastic responses including transgenerational plasticity (e.g., maternal effects), as well as developmental plasticity both within the larval phase and across the larval-juvenile life history transition (e.g., latent effects). Given the potential ecological and evolutionary consequences we think that there is much potential for research in the field of EcoDevo using brachyuran crabs as model organisms.

Description: Understanding organismal responses to environmental drivers is relevant to predict species capacities to respond to climate change. However, the scarce information available on intraspecific variation in the responses oversimplifies our view of the actual species capacities. We studied intraspecific variation in survival and larval development of a marine coastal invertebrate (shore crab Carcinus maenas) in response to two key environmental drivers (temperature and salinity) characterising coastal habitats. On average, survival of early larval stages (up to zoea IV) exhibited an antagonistic response by which negative effects of low salinity were mitigated at increased temperatures. Such response would be adaptive for species inhabiting coastal regions of freshwater influence under summer conditions and moderate warming. Average responses of developmental time were also antagonistic and may be categorised as a form of thermal mitigation of osmotic stress. The capacity for thermal mitigation of low-salinity stress varied among larvae produced by different females. For survival in particular, deviations did not only consist of variations in the magnitude of the mitigation effect; instead, the range of responses varied from strong effects to no effects of salinity across the thermal range tested. Quantifying intraspecific variation of such capacity is a critical step in understanding responses to climate change: it points towards either an important potential for selection or a critical role of environmental change, operating in the parental environment and leading to stress responses in larvae.

Description: One of the central issues in ecology is the identification of processes affecting the population structure and dynamics of species with complex life cycles. In such species, variation in both the number of larvae that enter a population and their phenotype are important drivers of survival and growth after metamorphosis. Larval experience can have strong effects on key post-metamorphic traits, but the temporal scale of such ‘trait-mediated effects’ may be short, and their magnitude may depend on the environment experienced after metamorphosis. We used an intertidal barnacle to study the long-term consequences of trait-mediated effects under different post-metamorphic conditions by manipulating larval food concentration and monitoring patterns of survival and growth in juveniles at 2 intertidal levels over a 5 mo period. In 2 replicated experiments, higher food levels resulted in increased body size, mass and reserves (measured from elemental composition) in the settling larval stage and increased body size of newly metamorphosed juveniles. In Expt 1, high food concentration reduced juvenile mortality at low intertidal levels, while on the upper intertidal, mortality was high for all larval food concentrations. By contrast, in Expt 2, low larval food concentration decreased juvenile survival at both shore levels. When present, effects were established early (Weeks 1 or 2) and persisted for over 10 wk in Expt 1 and 22 wk in Expt 2. Interactive effects of the larval and juvenile environments can have important implications for population size: trait-mediated effects may persist for long periods, helping to explain patterns of adult abundance.

Description: The effect of temperature and salinity on the larval development of the common spider crab Maja brachydactyla (Balss, 1922) were studied in the laboratory. Larvae were reared at different salinities (0–45) at constant temperature, and under six different combinations of temperature (18 and 21°C) and salinity (30, 35, and 40). The survival and developmental time from newly hatched zoeae to the megalopa stage and from megalopa to the first juvenile stage was quantified; the 24 h median lethal salinity (LS50) for first zoeal stage was calculated. Dry mass (DM), elemental body composition (Carbon, Hydrogen, Nitrogen) and carbon: nitrogen ratio (C:N) were determined in both starved and nourished zoeae. The lower and upper LS50 for M. brachydactyla first zoea in 24 h were 19.9 and 56.0, respectively; similar to other marine stenohaline brachyuran larvae. The megalopa stage was reached in a salinity range from 30 to 40. The highest survival rates to the first juvenile stage were observed at salinity: 35 and temperature: 21°C. Salinity was the key parameter for the survival to first juvenile, whereas the temperature had a higher effect over the duration of the larval development. The greatest loss of DM in starving and nourished zoeae was observed at low salinity (25). No differences were found in DM or C:N during the megalopa stage. The culture and ecological implications of the salinity tolerance of M. brachydactyla larvae are discussed.

Description: The brown crab is an important fishery resource in northern Europe. Understanding factors that affect fecundity in this species is complicated by the fact that ovigerous females enter traps infrequently. This study aimed to understand factors that affect brown crab fecundity and egg quality for crabs sampled from the waters around the Isle of Man. The size-fecundity relationship for the Isle of Man matched closely with those published for other geographical areas where a fishery exists for this species. Ovigerous crabs varied in size from 134 to 215 mm carapace width and each individual carried an estimated 0.4–3.0 million eggs. Fecundity was not affected by factors such as sampling season, location, loss of chelae, or black spot disease. Egg volume was independent of the number of eggs per batch or female body size. Egg volume was reduced significantly in crabs that had lost chelae. Egg dry weight, C and N composition did not vary with body size or any other explanatory factors such as chelal loss or the occurrence of black spot disease. Although the importance of the effect of claw loss on egg volume remains unclear, it may be an important consideration in fisheries in which the landing of claws is permitted.