High Degree Of Phenotypic Plasticity Research Articles

Phenotypic plasticity and carryover effects in an ecologically important bivalve in response to changing environments

Phenotypic plasticity can improve an organism’s fitness when exposed to novel environmental conditions or stress associated with climate change. Our study analyzed spatiotemporal differences in phenotypic plasticity and offspring performance in Olympia oysters Ostrea lurida. This species is an ecosystem engineer and is of great interest for commercial and restoration aquaculture. We used a multidisciplinary approach to examine acute and long-term physiological differences in O. lurida in response to in situ oceanographic conditions in a dynamic inland sea. We outplanted oysters to different areas in Puget Sound, Washington, affixing cages to anchor lines of oceanographic monitoring buoys. This allowed us to couple high-resolution oceanographic data with organism’s phenotypic response. To assess spatiotemporal differences in oyster physiological performance, we collected oysters after six-months and one year of acclimatization at four field sites. During each collection period we evaluated changes in shell properties, diet, metabolism, and reproduction. Adult growth, δ13C and δ15N isotopic signatures, and gametogenesis were affected by both seasonal and environmental conditions. In the winter, oysters from all sites had higher respiration rates when exposed to acute thermal stress, and lower respiration response to acute pH stress. Lipid content, sex ratio and shell strength were unchanged across locations. Offspring growth rates between sites at experimental temperature 20°C closely reflected parental growth rate patterns. Offspring survival was not correlated with growth rates suggesting different energetic trade-offs in oyster offspring. The metabolic response (respiration) of larvae reached its highest point at 20°C but sharply decreased at 25°C. This indicates that larvae are more sensitive to temperature stress, as adults did not exhibit a reduction in metabolic response at 25°C. By deploying genetically similar oysters into distinct environments and employing a wide range of physiological methodologies to examine performance and fitness, our results indicate that Olympia oysters exhibit a high degree of phenotypic plasticity and show evidence of parental carryover.

Inter-provenance variability and phenotypic plasticity of wood and leaf traits related to hydraulic safety and efficiency in seven European beech (Fagus sylvatica L.) provenances differing in yield

Abstract Key message Seven European beech provenances differing largely in growth performance were grown at two common garden sites in Germany and Slovakia. The intra-specific variability of most traits was explained more by phenotypic plasticity than inter-provenance variability, and efficiency-related traits showed a higher phenotypic plasticity than safety-related traits. Context To maintain climate-resilient future forests, replicated common-garden experiments are suited for developing assisted migration strategies for key tree species. Aims We analysed the magnitude of inter-provenance variability and phenotypic plasticity for 12 functional traits of European beech (Fagus sylvatica L.) and analysed whether the climate at the place of origin left an imprint. Moreover, we asked whether growth is unrelated to xylem safety and to what extent the foliar, xylem and growth-related traits are coordinated. Methods Terminal branches were collected from 19-year-old and 22-year-old trees of seven European beech provenances planted at two common garden sites in Germany and Slovakia, respectively. Three hydraulic, three wood anatomical and four foliar traits were measured and related to two growth-related variables. Results At the two sites, the same pair of provenances showed the highest and lowest growth. Nevertheless, a high degree of phenotypic plasticity was observed, as all traits differed significantly between sites after accounting for provenance effects, with hydraulic safety-related traits showing the lowest and efficiency-related traits the highest plasticity. There was no evidence for inter-provenance variability in xylem embolism resistance (P50) or the foliar carbon isotope signature (δ13C), a proxy for intrinsic water use efficiency (iWUE), and both were unrelated to growth. P50 was positively correlated with the lumen-to-sapwood area ratio and vessel density. Conclusions Because of the lacking trade-off between embolism resistance and growth, highly productive provenances can be selected without reducing the drought tolerance of the branch xylem. However, as xylem safety is only one element of a trees’ drought response, it may be beneficial to select provenances with other more conservative drought adaptations such as smaller vessel lumen areas for increasing xylem safety and small supported total leaf areas for reduction of total transpiration.

Increased Plasticity in Invasive Populations of a Globally Invasive Cactus.

Biological invasions pose global threats to biodiversity and ecosystem functions. Invasive species often display a high degree of phenotypic plasticity, enabling them to adapt to new environments. This study examines plasticity to water stress in native and invasive Opuntia ficus-indica populations, a prevalent invader in arid and semi-arid ecosystems. Through controlled greenhouse experiments, we evaluated three native and nine invasive populations. While all plants survived the dry treatment, natives exhibited lower plasticity to high water availability with only a 36% aboveground biomass increase compared to the invasives with a greater increase of 94%. In terms of belowground biomass, there was no significant response to increased water availability for native populations, but plants from the invasive populations showed a 75% increase from the dry to the wet treatment. Enhanced phenotypic plasticity observed in invasive populations of O. ficus-indica is likely a significant driver of their success and invasiveness across different regions, particularly with a clear environmental preference towards less arid conditions. Climate change is expected to amplify the invasion success due to the expansion of arid areas and desertification. Opuntia ficus-indica adapts to diverse environments, survives dry spells, and grows rapidly in times of high-water supply, making it a candidate for increased invasion potential with climate change.

Genetic drift versus natural selection affecting the evolution of spectral and functional traits of two key macrophytes: Phragmites australis and Nuphar lutea

Abstract Both genetic and phenotypic intraspecific diversity play a crucial role in the ecological and evolutionary dynamics of organisms. Several studies have compared phenotypic divergence (Pst) and differentiation of neutral loci (Fst) to infer the relative roles of genetic drift and natural selection in population differentiation (Pst–Fst comparison). For the first time, we have assessed and compared the genetic variation and differentiation at the leaf trait level in two key macrophytes, Phragmites australis and Nuphar lutea. To this aim, we quantified and described the genetic structure and phenotypic diversity of both species in five lake systems in north‐central Italy. We then investigated the relative roles of genetic drift and natural selection on leaf trait differentiation (Pst–Fst), assuming that Fst reflects divergence caused only by genetic drift while Pst also incorporates the effects of selective dynamics on the phenotype. In terms of genetic structure, the results for P. australis were in line with those observed for other Italian and European conspecific populations. Conversely, N. lutea showed a more complex genetic structure than expected at the site level, probably due to the combined effect of genetic isolation and its mixed mating system. Both species exhibited high variability in leaf functional traits within and among sites, highlighting a high degree of phenotypic plasticity. Pst–Fst comparisons showed a general tendency towards directional selection in P. australis and a more complex pattern in N. lutea. Indeed, the drivers of phenotypic differentiation in N. lutea showed a variable mix of stabilising and directional selection or neutral divergence at most sites. The prevalence of vegetative over generative reproduction leads P. australis populations to be dominated by a few clones that are well adapted to local conditions, including phenotypes that respond plastically to the environment. In contrast, in N. lutea, the interaction of a mixed mating system and geographical isolation among distant sites tends to reduce the effect of outbreeding depression and provides the genetic basis for adaptive capacity. The first joint analysis of the genetic structure of these two key macrophytes allowed a better understanding of the relative roles of genetic drift and natural selection in the diversification of phenotypic traits within habitats dominated by P. australis and N. lutea.

Functional ecology of planktonic ciliates: Measuring mortality rates in response to starvation.

Population dynamics of aquatic ciliates are controlled "bottom-up" via food supply and "top-down" by grazing and parasitism. While intrinsic growth rates of ciliates under saturating food conditions have been studied in some detail, mortality rates induced by starvation have received little attention thus far. To this end, we examined the response of three algivorous freshwater ciliate species to starvation using three different optical methods. Two of these methods, i.e. ciliate mortality rates (δ) estimated from (i) numerical response experiments and (ii) the rate of decline (ROD) in cell numbers, investigated the response of the ciliate population using conventional light microscopy. The third method, imaging cytometry using a FlowCAM instrument, monitored single cells during the starvation experiment. Like light microscopy, the FlowCAM approach estimated δ based on ROD in the experimental containers. However, imaging cytometry also measured the relative cellular chlorophyll a content in the ciliates' food vacuoles as a proxy for the nutritional status of the cells. The linear decline of the cellular chl. a yielded an independent estimate of δ that was similar to δ calculated from ROD. Additionally, the FlowCAM measurements revealed a high degree of phenotypic plasticity of the ciliates when exposed to starvation.

The Influence of Variety and Climatic Year on the Phenology of Blueberry Grown in the Banat Area, Romania

This paper’s aim was to investigate the influence of variety and the climatic year on vegetation phenophases in blueberries grown in southwest Romania, the Banat region. This study was carried out during the growing season of 2020–2022 in a blueberry plantation, for ‘Duke’, ‘Hannah’s Choice’ and ‘Elliott’ varieties. In the study, phenological traits were recorded using the BBCH phenological scale and the observation of phenotypic data was recorded as in Julian days. Thus, it is found that the duration of each phenophase characterized each variety. The calendar periods for the onset of vegetation and the duration of spring phenological development stages in varieties have differed from year to year and depended on weather conditions. In the case of the phenological stage, depending on variety, the maximum amplitude was recorded for BBCH 87 stage (75% blue fruits) of 51 days, and the minimum amplitude, of 25 days, for BBCH 51 stage (bud swell) and BBCH 59 (late pink bud). The coefficient of variation, depending on climatic year, for generative phenophases, had values between 6.5% (BBCH 67-petal fall) and 21.1% (BBCH 51-bud swell). It was found that the variety and the climatic year influence the development of vegetation phenophases. The results indicate that blueberry cultivars have demonstrated a high degree of phenotypic plasticity to respond to gradual changes in environmental conditions and are important for the evaluation of cultivar cultivation prospects in the studied area.

PHENOTYPIC PLASTICITY OF THE AMUR SLEEPER (<i>PERCCOTTUS GLENII</i>) INVASIVE POPULATIONS DURING THE COLONISATION OF WATER BODIES

The variability of the body shape in invasive fish species - Amur sleeper (Perccottus glenii) - from natural and anthropogenic water bodies of the Middle Urals with different completeness of the species composition was studied by the use of geometric morphometrics methods. We compared samples of the Amur sleeper from neighboring adjacent water bodies - Lake Shitovskoye and two peat quarries filled with water. Samples of different seasons and years of collection were taken in the lake, which allowed us to correlate the influence of climate and season on the morphogenesis of the Amur sleeper. According to the control catches, the fish community of the lake is represented by 10 species, i.e. it has a poly-species composition: 6 native species (roach, river perch, ruff, tench, crucian carp, and pike) and 4 alien species (bream, belica, Amur sleeper, carp). The share of the Amur sleeper in the control catches in the lake was no more than 3-5%. In the water bodies of peat quarries, oligoid communities of 2 species were formed (Amur sleeper and crucian carp). Discriminant analysis of the body shape of fish from the lake and peat pits allowed us to reveal the origin of 93-98% of individuals. Comparing the samples of the younger (2+-3+ years) and older (4+-7+ years) age groups of fish divided by sex and biotope, different directions of changes in the shape of the Amur sleeper body in ontogenesis were revealed between the biotopic groups. The range of age variability was almost 5 times lesser than the intergroup biotopic differences of fish from ecologically contrasting water bodies. Seasonal and inter-annual intra-population variability of body shape in the Amur sleeper in the lake is significantly lesser pronounced than the intergroup differences between samples from the lake and peat quarries. Sex differences accounted for only 6% of the intergroup variance (3 times lower than the level of age differences), and in the poly-species lake community, sex differences decrease with age, and in the water bodies of quarries, on the contrary, they increase. Within-group morphological disparity ( MNND ) is significantly higher in samples from peat quarries. The data obtained are of a key character, since they characterize a high degree of phenotypic plasticity of the Amur sleeper and a rapid adaptive restructuring of its morphogenesis to different conditions of natural and anthropogenic water bodies of the Middle Urals.

Phenotypic plasticity couples with transcriptomic flexibility in Leymus chinensis under diverse edaphic conditions

Phenotypic plasticity is widespread in all organisms. This biological property is particularly important for sessile organisms like plants to cope with the ever-changing environmental conditions. Leymus chinensis is a predominantly clonal grass that adapts to diverse stressful habitats including drought, cold and salinity-alkalinity. Previous studies suggest that the remarkable environmental adaption of L. chinensis is probably due to its high degree of phenotypic plasticity; however, the underlying molecular mechanism remains unexplored. In this study, we grew L. chinensis clonal plants in four soil types that differ in nutrient content, nitrate-nitrogen concentration and pH. We observed plasticity in several phenotypic traits in response to specific edaphic factors. By employing de novo RNA-sequencing assembly, we curated differentially expressed genes (DEGs) under each soil type. We found that DEGs under each edaphic condition were enriched for highly specific as well as common GO or KEGG terms known to be biologically relevant to the respective conditions. Moreover, gene activation or silencing was also highly condition-dependent. Together, our results suggest that the high phenotypic plasticity of L. chinensis is likely rooted in its evolved intrinsic property of expressing specific transcriptome profiles in response to diverse niche conditions. • Diverse soils lead to plastic phenotypes in L. chinensis with flexible and condition-specific gene expression.

Dissimilarity between Andropogon lateralis ecotypes under different defoliation frequencies and heights

ABSTRACT: Andropogon lateralis Nees is a native grass of southern Brazil and is one of the most frequent specie found in native grasslands. The species is widely distributed and has a high degree of phenotypic plasticity, which makes it highly adaptable to different edaphoclimatic conditions and management. This study aimed to evaluate the behavior of twelve ecotypes of A. lateralis, collected in different regions of the state of Rio Grande do Sul and cut to three different heights and subjected to two different defoliation frequencies. From September to February, the ecotypes were evaluated for total dry matter, leaf and stem yields. In addition, total, vegetative and reproductive tillers and plant height were measured. These characteristics are important for the selection of superior genotypes in terms of genetic variability and forage production. Total dry matter and leaf dry matter are characteristics with agronomic importance and they showed the highest correlation (r = 0.77), enabling an indirect selection for one of these characteristics. The natural selection of plants resulted in distinct structural, morphological and productive characteristics with heterogeneity that allows the selection and grouping according to the characteristics, ecotypes with superior agronomic characteristics can be included in breeding programs.

What is the expected human childhood? Insights from evolutionary anthropology.

In psychological research, there are often assumptions about the conditions that children expect to encounter during their development. These assumptions shape prevailing ideas about the experiences that children are capable of adjusting to, and whether their responses are viewed as impairments or adaptations. Specifically, the expected childhood is often depicted as nurturing and safe, and characterized by high levels of caregiver investment. Here, we synthesize evidence from history, anthropology, and primatology to challenge this view. We integrate the findings of systematic reviews, meta-analyses, and cross-cultural investigations on three forms of threat (infanticide, violent conflict, and predation) and three forms of deprivation (social, cognitive, and nutritional) that children have faced throughout human evolution. Our results show that mean levels of threat and deprivation were higher than is typical in industrialized societies, and that our species has experienced much variation in the levels of these adversities across space and time. These conditions likely favored a high degree of phenotypic plasticity, or the ability to tailor development to different conditions. This body of evidence has implications for recognizing developmental adaptations to adversity, for cultural variation in responses to adverse experiences, and for definitions of adversity and deprivation as deviation from the expected human childhood.

Gymnotus paraguensis, a Good Example of Phenotypic Plasticity in the Pantanal Biome, Brazil.

Gymnotus is the most studied genus of the order Gymnotiformes, but the morphological similarities of the different species make it difficult to identify taxa reliably. The present study is a continuation of the ongoing research into the taxonomic diversity of the stocks of Gymnotus sold as live bait in the Pantanal, Brazil. These studies have been based on cytogenetic analyses, DNA barcoding, and the analysis of coloration patterns. The results of the cytogenetic analysis confirmed the presence of three distinct strains, recognized as Gymnotus paraguensis, G. sylvius, and G. pantanal. However, the results revealed that the molecular operational taxonomic units identified as G. paraguensis actually include a relatively diverse set of fish, separated by considerable genetic distances. As the G. paraguensis specimens also presented considerable variation in coloration patterns, further genetic diversity analyses were conducted on these individuals, to test the hypothesis that more than one species is present in this cytotaxonomic unit. The haplotype network revealed a regional pattern in the distribution of this species. The results indicate that the observed variation in coloration patterns is associated with a high degree of phenotypic plasticity in G. paraguensis. These findings emphasize the importance of using an integrative approach for a more accurate diagnosis of Gymnotus, in particular, the species marketed as live bait for the fisheries of the upper Paraguay River basin in the Brazilian Pantanal.

Adaptive versus non-adaptive responses to drought in a non-native riparian tree / shrub, Tamarix spp

ABSTRACT Rapidly colonizing species often thrive in a wide-range of conditions due to a high degree of phenotypic plasticity that results in populations of “general purpose” genotypes. Alternatively, species with high genetic variation could rapidly respond to forces of selection such that a local population evolves traits that provide an advantage in its local environment. We tested this generalist versus local adaptation paradigm in a widely distributed, recently introduced riparian tree / shrub, Tamarix spp. Using an eighty-day, mid-summer common garden drought experiment, we tested three inter-related hypotheses: 1) stomatal sensitivity to soil water depletion is lower in genotypes from a low-elevation, ephemerally flowing river than genotypes from a low-elevation, perennially flowing river, indicative of local adaptation to hydrological conditions, 2) stomatal sensitivity to soil water depletion is lower in genotypes from high-elevations with regular freeze-thaw exposure than genotypes sourced from locations with no freeze-thaw exposure, indicative of local adaptation to temperature conditions, and 3) differences among genotypes in drought sensitivity are correlated with differences in fine root area to leaf area ratios (Ar:Al). For the most part, results did not support hypothesis 1, but largely supported hypotheses 2 and 3. Specifically, sap-flux scaled canopy transpiration (El) declined 14 days earlier in the low-elevation populations after drought initiation compared to El of the highest elevation population with the highest freeze-thaw exposure. Root area to leaf area ratios of the two low-elevation populations were also only 42% and 55% of Ar:Al in the highest elevation population. Results indicate that the high degree of reported Tamarix hybridization since its introduction to North America has largely produced a swarm of “generalist” genotypes in terms of drought sensitivity. Nevertheless, rapid changes in ecohydrologic conditions may result in some Tamarix populations becoming maladapted sooner to reductions in available water than others in the western US.

Leaf morphological plasticity in three dominant tree species in the Sundarbans mangrove forest of Bangladesh in different salinity zones

Mangrove tree species show plasticity in their leaf morphological traits in different salinity zones. However, leaf morphological plasticity and its causes in different salinity zones are incompletely understood. To understand the mechanism of plasticity, this study investigated the responses of three dominant tree species Sundri (Heritiera fomes), Gewa (Excoecaria agallocha) and Goran (Ceriops decandra) of the Sundarbans to the salinity gradients. A total of 17 leaf parameters were measured and quantified. All collected data were analyzed using univariate and multivariate statistical tools to investigate leaf morphological plasticity. A wide range of phenotypic plasticity was observed in all leaf parameters studied among the salinity zones of the Sundarbans. One-way ANOVA and Tukey’s posthoc test revealed significant differences (P < 0.05) in all leaf parameters among the salinity zones and confirming that there was a high degree of phenotypic plasticity among the salinity zones of the Sundarbans. Petiole length (PL), leaf area (LA) and leaf length/petiole length (LL/PL) showed high level of plasticity among the salinity zones of the Sundarbans for each species of Sundri, Gewa and Goran. Plasticity index (PI) was developed in this study for each species studied. High level of phenotypic plasticity in these leaf traits reflects fitness of these species to different saline environments. Our results provide clear evidence that all the leaf parameters measured for three tree species viz., Sundri, Gewa and Goran effectively utilizes a plastic strategy in different salinity zones in the Sundarbans. Morphological trait plasticity could serve as powerful biological indicators to predict the shift of leaf morphology in upcoming environmental change events like sea level rise and reduction of fresh water flow from upstream.

Metabolic Targeting of Cancer Stem Cells

Most human tumors possess a high heterogeneity resulting from both clonal evolution and cell differentiation program. The process of cell differentiation is initiated from a population of cancer stem cells (CSCs), which are enriched in tumor‐regenerating and tumor‐propagating activities and responsible for tumor maintenance and regrowth after treatment. Intrinsic resistance to conventional therapies, as well as a high degree of phenotypic plasticity, makes CSCs hard-to-target tumor cell population. Reprogramming of CSC metabolic pathways plays an essential role in tumor progression and metastatic spread. Many of these pathways confer cell adaptation to the microenvironmental stresses, including a shortage of nutrients and anti-cancer therapies. A better understanding of CSC metabolic dependences as well as metabolic communication between CSCs and the tumor microenvironment are of utmost importance for efficient cancer treatment. In this mini-review, we discuss the general characteristics of CSC metabolism and potential metabolic targeting of CSC populations as a potent strategy to enhance the efficacy of conventional treatment approaches.

Effects of auxin derivatives on phenotypic plasticity and stress tolerance in five species of the green algaDesmodesmus(Chlorophyceae, Chlorophyta)

Green microalgae of the genus Desmodesmus are characterized by a high degree of phenotypic plasticity (i.e. colony morphology), allowing them to be truly cosmopolitan and withstand environmental fluctuations. This flexibility enables Desmodesmus to produce a phenotype–environment match across a range of environments broader compared to algae with more fixed phenotypes. Indoles and their derivatives are a well-known crucial class of heterocyclic compounds and are widespread in different species of plants, animals, and microorganisms. Indole-3-acetic acid (IAA) is the most common, naturally occurring plant hormone of the auxin class. IAA may behave as a signaling molecule in microorganisms, and the physiological cues of IAA may also trigger phenotypic plasticity responses in Desmodesmus. In this study, we demonstrated that the changes in colonial morphs (cells per coenobium) of five species of the green alga Desmodesmus were specific to IAA but not to the chemically more stable synthetic auxins, naphthalene-1-acetic acid and 2,4-dichlorophenoxyacetic acid. Moreover, inhibitors of auxin biosynthesis and polar auxin transport inhibited cell division. Notably, different algal species (even different intraspecific strains) exhibited phenotypic plasticity different to that correlated to IAA. Thus, the plasticity involving individual-level heterogeneity in morphological characteristics may be crucial for microalgae to adapt to changing or novel conditions, and IAA treatment potentially increases the tolerance of Desmodesmus algae to several stress conditions. In summary, our results provide circumstantial evidence for the hypothesized role of IAA as a diffusible signal in the communication between the microalga and microorganisms. This information is crucial for elucidation of the role of plant hormones in plankton ecology.

Antagonistic relationship between the unfolded protein response and myocardin-driven transcription in smooth muscle.

Smooth muscle cells (SMCs) are characterized by a high degree of phenotypic plasticity. Contractile differentiation is governed by myocardin-related transcription factors (MRTFs), in particular myocardin (MYOCD), and when their drive is lost, the cells become proliferative and synthetic with an expanded endoplasmic reticulum (ER). ER is responsible for assembly and folding of secreted proteins. When the load on the ER surpasses its capacity, three stress sensors (activating transcription factor 6 [ATF6], inositol-requiring enzyme 1α [IRE1α]/X-box binding protein 1 [XBP1], and PERK/ATF4) are activated to expand the ER and increase its folding capacity. This is referred to as the unfolded protein response (UPR). Here, we hypothesized that there is a reciprocal relationship between SMC differentiation and the UPR. Tight negative correlations between SMC markers (MYH11, MYOCD, KCNMB1, SYNPO2) and UPR markers (SDF2L1, CALR, MANF, PDIA4) were seen in microarray data sets from carotid arterial injury, partial bladder outlet obstruction, and bladder denervation, respectively. The UPR activators dithiothreitol (DTT) and tunicamycin (TN) activated the UPR and reduced MYOCD along with SMC markers in vitro. The IRE1α inhibitor 4μ8C counteracted the effect of DTT and TN on SMC markers and MYOCD expression. Transfection of active XBP1s was sufficient to reduce both MYOCD and the SMC markers. MRTFs also antagonized the UPR as indicated by reduced TN and DTT-mediated induction of CRELD2, MANF, PDIA4, and SDF2L1 following overexpression of MRTFs. The latter effect did not involve the newly identified MYOCD/SRF target MSRB3, or reduced production of either XBP1s or cleaved ATF6. The UPR thus counteracts SMC differentiation via the IRE1α/XBP1 arm of the UPR and MYOCD repression.

A New Vent Limpet in the Genus Lepetodrilus (Gastropoda: Lepetodrilidae) From Southern Ocean Hydrothermal Vent Fields Showing High Phenotypic Plasticity

The recently discovered hydrothermal vent ecosystems in the Southern Ocean host a suite of vent-endemic species, including lepetodrilid limpets dominating in abundance. Limpets were collected from the chimneys, basalts and megafauna of the East Scotia Ridge segments E2 and E9 and the Kemp Caldera at the southern end of the South Sandwich Island arc. The limpets varied in size and shell morphology between vent fields and displayed a high degree of phenotypic plasticity. Size frequency analyses between vent fields suggests continuous reproduction in the limpet and irregular colonisation events. Phylogenetic reconstructions and comparisons of mitochondrial COI gene sequences revealed a level of genetic similarity between individuals from the three vent fields consistent with their belonging to a single molecular operational taxonomic unit. Here we describe Lepetodrilus concentricus n. sp., and evaluate its genetic distinctness and pylogenetic position with congeners based on the mitochondrial COI gene. Results indicate that L. concentricus n. sp. is a sister species towith the two species estimated to have diverged within the last ~5 million years.

3D type I collagen environment leads up to a reassessment of the classification of human macrophage polarizations

Macrophages have multiple roles in development, tissue homeostasis and repair and present a high degree of phenotypic plasticity embodied in the concept of polarization. One goal of macrophage biology field is to characterize these polarizations at the molecular level. To achieve this task, it is necessary to integrate how physical environment signals are interpreted by macrophages under immune stimulation. In this work, we study how a 3D scaffold obtained from polymerized fibrillar rat type I collagen modulates the polarizations of human macrophages and reveal that some traditionally used markers should be reassessed. We demonstrate that integrin β2 is a regulator of STAT1 phosphorylation in response to IFNγ/LPS as well as responsible for the inhibition of ALOX15 expression in response to IL-4/IL-13 in 3D. Meanwhile, we also find that the CCL19/CCL20 ratio is reverted in 3D under IFNγ/LPS stimulation. 3D also induces the priming of the NLRP3 inflammasome resulting in an increased IL-1β and IL-6 secretion. These results give the molecular basis for assessing collagen induced immunomodulation of human macrophages in various physiological and pathological contexts such as cancer.

Importance of Experimental Environmental Conditions in Estimating Risks and Associated Uncertainty of Transgenic Fish Prior to Entry into Nature

Salmonids show a high degree of phenotypic plasticity that can differ among genotypes, and this variation is one of the major factors contributing to uncertainty in extrapolating laboratory-based risk assessment data to nature. Many studies have examined the relative growth and survival of transgenic and non-transgenic salmonids, and the results have been highly variable due to genotype × environment interactions. The relative survival of fast- and slow-growing strains can reverse depending on the environment, but it is not clear which specific environmental characteristics are driving these responses. To address this question, two experiments were designed where environmental conditions were varied to investigate the contribution of rearing density, food amount, food type, habitat complexity, and risk of predation on relative growth and survival of fast-growing transgenic and slow-growing wild-type coho salmon. The first experiment altered density (high vs. low) and food amount (high vs. low). Density impacted the relative growth of the genotypes, where transgenic fish grew more than non-transgenic fish in low density streams, regardless of food level. Density also affected survival, with high density causing increased mortality for both genotypes, but the mortality of transgenic relative to non-transgenic fish was lower within the high-density streams, regardless of food level. The second experiment altered habitat complexity (simple vs. complex), food type (artificial vs. natural), amount of food (normal vs. satiation), and risk of predation (present vs. absent). Results from this experiment showed that genotype affected growth and survival, but genotype effects were modulated by one or more environmental factors. The effect of genotype on survival was influenced by all examined environmental factors, such that no predictable trend in relative survival of transgenic versus non-transgenic fry emerged. This was primarily due to variations in survival of non-transgenic fish under different environmental conditions (non-transgenic fry had highest survival in hatchery conditions, and lowest survival in complex conditions with natural food fed at a normal level with or without predators). Transgenic fry survival was only significantly influenced by predator presence. The effects of genotype on mass and length were significantly modulated by food type only. Transgenic fry were able to gain a large size advantage over non-transgenic fish when fed artificial food under all habitat types. These experiments support the observations of dynamic responses in growth and survival depending on the environment, and demonstrate the challenge of applying laboratory-based experiments to risk assessment in nature.

Evaluation of a long-established silvopastoral Brachiaria decumbens system: plant characteristics and feeding value for cattle

One of the main challenges of using a silvopastoral system (SPS) is maintaining pasture and animal productivity over time. Our objective was to compare the productive characteristics and nutritive value of signal grass (Brachiaria decumbens cv. Basilisk) and the liveweight gain of dairy heifers in a SPS and open pasture (OP, signal grass under full sunlight) during the rainy seasons of four experiments between 2003 and 2016, which characterised systems from their 6th to 19th years after establishment in south-eastern Brazil when analysed together. The experimental design was a randomised complete block in a 2 × 4 factorial scheme (two production systems (SPS and OP) and four experiments (2003–2004, 2004–2007, 2011–2014 and 2014–2016)). From the 7th year onwards, the progressive reduction of photosynthetically active radiation negatively impacted the productive characteristics of the SPS pasture. Total forage mass was reduced by 19% in SPS compared with the OP in 2004–2007, 38% in 2011–2014 and 31% in 2014–2016. Crude protein content was 23% and 30% higher in the SPS than in the OP in 2011–2014 and 2014–2016, respectively. However, during the study period (until the 19th year), the liveweight gain of heifers was similar between systems since the higher crude protein content available in SPS contributed to improved forage nutritional value. From the 17th to the 19th year, weight gain per area was lower in the SPS compared with the OP (169 vs 199 kg ha–1), although the difference between systems was small. Signal grass presents a high degree of phenotypic plasticity in response to changes in shade levels, which gives this species a high potential for use in SPS.