Common Environmental Conditions Research Articles

Domestic-wild hybridization to improve aquaculture performance in Chinook salmon

Salmon farming is one of Canada's fastest growing industries and contributes to Canada's economy as well as creating jobs in rural areas; however, the industry is challenged by the need to balance production economics against environmental impacts. While Atlantic salmon (Salmo salar) are the most commonly farmed species on the west coast of Canada, Chinook salmon (Oncorhynchus tshawytscha) are a valuable alternative, as they fill a niche market and generate reduced environmental concerns because they are a native species. However, Chinook salmon have not been systematically domesticated, and their performance remains highly variable. Here we report on the results of a research program designed to develop a performance-enhanced hybrid Chinook salmon stock. Growth and survival were estimated for seven domestic-wild hybrid Chinook salmon crosses at various freshwater stages and during 15 months of saltwater rearing at a British Columbia Chinook salmon farm and compared with domestic-domestic crosses (control). The project included 8640 individually (PIT) tagged offspring from the domestic stock and seven domestic-wild hybrid stocks originating from the Lower Fraser Valley, Lower Mainland Vancouver, and Vancouver Island, British Columbia, Canada. Within each stock, milt from 10 sires was used to fertilize eggs pooled from 15 highly inbred domestic females to produce 80 half-sib families. Our breeding design allows the partitioning of stock and sire effects, and minimises maternal genetic and maternal environment effects. Replicates of all families were reared under common environmental conditions in both fresh- and salt water and monitored for body size and survival. There was significant variation in survival, body size, and saltwater biomass among the Chinook salmon hybrid stocks. The performance of some of the hybrid crosses exceeded that of the fully domesticated stock, although the pattern of performance varied with rearing stage. Overall, two hybrid stocks consistently outperformed the domestic stock in terms of survival, growth, and biomass estimates. We systematically assess production performance across a wide range of wild-domestic hybrid crosses in a Pacific salmon species, and our results highlight opportunities to improve the production performance of Chinook salmon culture.

Comparative physiological and transcriptomic analyses reveal salt tolerance mechanisms of Zygosaccharomyces rouxii

Abstract Zygosaccharomyces rouxii is widely applied in the production of fermented foods, where salt stress is a common environmental condition encountered. In this study, salt stress response of Z. rouxii was investigated based on physiological and transcriptomic analyses, and the results showed that Z. rouxii evoked a global regulation to resist salt stress. Analysis of physiological data showed that salt stress led to accumulation of glycerol and trehalose, and increase of unsaturated fatty acids-proportions. Intracellular amino acid analysis showed that the content of 4 amino acids (threonine, tyrosine, lysine and proline) increased significantly and 2 amino acids (serine and lysine) decreased. In addition, scanning electron microscopy analyses showed that the cell surface of Z. rouxii became rough and cell wall ruptured accompanied by intracellular spillover after salt stress. Comparison of transcriptome data showed that the genes involved in cellular metabolism and ribosome biosynthesis exhibited differently expression, which is consistent with the results of physiological data. Results presented in this study may be helpful in understanding the salt tolerance mechanism of Z. rouxii, and provide theoretical support of its application during food fermentation.

Improvement of moisture damage resistance and permanent deformation performance of asphalt mixtures with marginal porous volcanic aggregates using crumb rubber modified bitumen

The main volumetric and engineering characteristics of hot mix asphalt with crumb rubber modified bitumen from used tyres and high-porosity volcanic aggregates are presented and compared to the same mixtures with conventional bitumen. In volcanic territories, these marginal aggregates are the most common lithotypes and environmental protection conditions require the reuse of both wastes. Two aspects were evaluated: a) characterization of volcanic aggregates and their classification for construction purposes; b) characterization of asphalt-rubber mixtures with highly-vesiculated basalt and different binder contents. It was found that most of the properties of these mixtures efficiently improved due to the utilization of asphalt-rubber, specially the rutting resistance, water damage resistance and stability, thus complying with the standard specifications for pavements and offering sufficient dynamic stiffness modulus. This technique may be applied to other volcanic territories where these local natural aggregates are found in abundance and so contribute to better development of these regions as well as ensuring longer durability of asphalt pavements.

No sex differences in the origins of covariation between social and physical aggression.

Prior work has indicated both theoretical and empirical overlap between social and physical aggression. The extent to which their covariance can be explained by the same underlying genetic or environmental factors, however, remains unclear. It is also uncertain whether or how the origins of their covariance might vary across sex. The current study sought to fill these gaps in the literature. We examined maternal and teacher reports of youth physical and social aggression in over 1000 6-10 years old (mean age = 8.02 years) twin pairs from the Michigan State University Twin Registry. We made use of the bivariate correlated factors model to clarify the origins of their association. We further tested both sex difference and no-sex difference versions of that model to determine whether there are sex differences in the association between social and physical aggression, as often assumed. The covariation between social and physical aggression was due to overlapping genetic factors and common environmental conditions. Specifically, 50-57% of the genetic factors, 74-100% of the shared environmental factors, and 28-40% of the unique environmental factors influencing physical aggression also influenced social aggression according to both mother and teacher reports. These shared etiological factors did not differ across sex. These findings argue against the common assumption that social aggression is the 'female version' of male physical aggression, and instead suggest that social aggression may be best conceptualized as a form of antisocial behavior that shares developmental pathways with other manifestations of externalizing pathology.

Hypoxia and the group VII ethylene response transcription factor HRE2 promote adventitious root elongation in Arabidopsis.

Soil water‐logging and flooding are common environmental stress conditions that can impair plant fitness. Roots are the first organs to be confronted with reduced oxygen tension as a result of flooding. While anatomical and morphological adaptations of roots are extensively studied, the root system architecture is only now becoming a focus of flooding research. Adventitious root (AR) formation shifts the root system higher up the plant, thereby facilitating supply with oxygen, and thus improving root and plant survival.We used Arabidopsis knockout mutants and overexpressors of ERFVII transcription factors to study their role in AR formation under hypoxic conditions and in response to ethylene.Results show that ethylene inhibits AR formation. Hypoxia mainly promotes AR elongation rather than formation mediated by ERFVII transcription factors, as indicated by reduced AR elongation in erfVII seedlings. Overexpression of HRE2 induces AR elongation to the same degree as hypoxia, while ethylene overrides HRE2‐induced AR elongation.The ERFVII transcription factors promote establishment of an AR system that is under negative control by ethylene. Inhibition of growth of the main root system and promotion of AR elongation under hypoxia strengthens the root system in upper soil layers where oxygen shortage may last for shorter time periods.

Cryptic genetic variation and adaptation to waterlogging in Caledonian Scots pine, Pinus sylvestris L.

Local adaptation occurs as the result of differential selection among populations. Observations made under common environmental conditions may reveal phenotypic differences between populations with an underlying genetic basis; however, exposure to a contrasting novel environment can trigger release of otherwise unobservable (cryptic) genetic variation. We conducted a waterlogging experiment on a common garden trial of Scots pine, Pinus sylvestris (L.), saplings originating from across a steep rainfall gradient in Scotland. A flood treatment was maintained for approximately 1 year; physiological responses were gauged periodically in terms of photochemical capacity as measured via chlorophyll fluorescence. During the treatment, flooded individuals experienced a reduction in photochemical capacity, F v /F m, this reduction being greater for material originating from drier, eastern sites. Phenotypic variance was increased under flooding, and this increase was notably smaller in saplings originating from western sites where precipitation is substantially greater and waterlogging is more common. We conclude that local adaptation has occurred with respect to waterlogging tolerance and that, under the flooding treatment, the greater increase in variability observed in populations originating from drier sites is likely to reflect a relative absence of past selection. In view of a changing climate, we note that comparatively maladapted populations may possess considerable adaptive potential, due to cryptic genetic variation, that should not be overlooked.

Role of ionic strength in the retention and initial attachment of Pseudomonas putida to quartz sand.

Biofilms in soil can offer solutions to many geotechnical problems. Controlling biofilm formation in soil requires a fundamental understanding of how bacterial cells interact with soil under relevant environmental conditions. Here, atomic force microscopy (AFM) was used to quantify the adhesion forces acting between a model soil microbe, Pseudomonas putida, and a model of quartz sand under a range of ionic strengths (ISs; 0.02M-0.52M) that bracket common environmental conditions present in soil. AFM forces were decoupled into specific and nonspecific components following the established Poisson statistical analysis method. The experimental nonspecific forces were compared to theoretical forces calculated using the soft-particle analysis of the Derjaguin, Landau, Verwie, and Overbeek theory of colloidal interactions. Their data indicated that both specific and nonspecific forces increased as the IS increased with specific forces being 37% higher on average than nonspecific forces. The AFM findings were validated by measuring the transport of P. putida in sand columns kinetically as a function of IS. Collected breakthrough curves were modeled using one-dimensional colloidal filtration theory. Their nanoscale AFM measurements of bacterial adhesion correlated positively with the bacterial macroscale sticking collision efficiencies with both increasing as the IS increased. Collectively, their results suggest that applying biofilms for bioclogging applications is suitable in sandy, hydrophobic environments with elevated ISs where specific forces such as hydrogen bonds or hydrophobic interactions may have a critical role in promoting bacterial adhesion.

A Comparison Between the Macroscopic Anatomy of the Cecum in Laboratory Rat and Guinea Pig

Controlled food and maintenance conditions cause both functional and anatomical adaptations of digestive system. The rat and guinea pig, used both as experimental models and as pets, shared common controlled environmental conditions. The two species were exposed during the generation to artificial conditions rather that natural ones. The effects of these conditions on the macroscopic anatomy of the cecum have been documented.

The genetic variance but not the genetic covariance of life-history traits changes towards the north in a time-constrained insect.

Seasonal time constraints are usually stronger at higher than lower latitudes and can exert strong selection on life-history traits and the correlations among these traits. To predict the response of life-history traits to environmental change along a latitudinal gradient, information must be obtained about genetic variance in traits and also genetic correlation between traits, that is the genetic variance-covariance matrix, G. Here, we estimated G for key life-history traits in an obligate univoltine damselfly that faces seasonal time constraints. We exposed populations to simulated native temperatures and photoperiods and common garden environmental conditions in a laboratory set-up. Despite differences in genetic variance in these traits between populations (lower variance at northern latitudes), there was no evidence for latitude-specific covariance of the life-history traits. At simulated native conditions, all populations showed strong genetic and phenotypic correlations between traits that shaped growth and development. The variance-covariance matrix changed considerably when populations were exposed to common garden conditions compared with the simulated natural conditions, showing the importance of environmentally induced changes in multivariate genetic structure. Our results highlight the importance of estimating variance-covariance matrixes in environments that mimic selection pressures and not only trait variances or mean trait values in common garden conditions for understanding the trait evolution across populations and environments.

Relationship between marine growth and sea survival of two anadromous salmonid fish species

This study found empirical evidence supporting the “growth–survival” paradigm in the marine phase of Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta). The paradigm postulates that larger or faster-growing individuals are more likely to survive than smaller or slower-growing conspecifics. The study employed long-term (25 year) capture data from a trap in the River Halselva in Norway during annual migration between marine and freshwater environments. Similar results were found for both species. Growth during the sea sojourn and return rates were positively correlated, linking increased survival with growth. Specific growth rate, survival, and duration of the sea sojourn of first-time migrants were correlated, suggesting that common environmental conditions at sea influence annual fish productivity. Freshwater and sea temperatures affected migration timing, whereas annual variation in marine growth and survival did not correlate with temperatures. This suggests that other factors such as variation in energy intake were the main source of annual growth variations. Moreover, the marine growth rate of the two species may signal annual overall fjord ecosystem production, especially related to their main prey.

Growth and physiological sapling responses of eleven Quercus ilex ecotypes under identical environmental conditions

Abstract Studies with holm oak indicate that genetic variation may result in substantial differences in drought tolerance among its ecotypes. However, few trials have studied this variation under common environmental conditions. This study aimed to assess physiological and morphological responses of holm oak saplings for 11 ecotypes that represent a longitudinal transect across south-central Spain (Andalusia). Drought resistance was assessed by measuring growth, xylem water potential, chlorophyll fluorescence, and photosynthesis. Possible relationships among morphological and physiological responses across ecotypes were determined using Pearson product-moment correlations and multiple linear regressions. The response variables were used in multivariate analyses including discriminant function analysis, principal component and cluster analyses. Last, we used sparse Partial Least Squares regression (sPLS) to analyse the relationships between the morpho-physiological responses and biophysical parameters of the parent locations. Our results indicate that Q. ilex ecotypes growing in a common garden setting exhibited substantial variation in morphological and physiological traits. At the end of the growth trial (65 months post-planting), basal diameter, leaf area, and midday water potential were higher in Q. ilex ecotypes from western sites compared to eastern sites across Andalusia. PCA and clustering revealed clear morphological and physiological differentiation in response to gradients of geographical and ecological variation in ecotype origin. Variables that were related to the water regime of the ecotypes, such as seasonal precipitation and evapotranspiration, showed stronger correlations with ecotype responses. Consequently, eastern ecotypes were more likely to spread in response to projected increases in temperatures and declines in summer precipitation; however, western ecotypes would likely decrease in response to hotter and drier summers.

Cyperus stroudii (CYPERACEAE), a new species from Ascension Island, South Atlantic Ocean

Material from the Cyperus appendiculatus group was collected from Ascension Island and compared using a common garden study and to herbarium specimens from throughout the geographical range. Cyperus stroudii is described as a new species, known only from Ascension Island in the South Atlantic Ocean, it closest relative is C. appendiculatus also native to Ascension Island and Brazil. Cyperus stroudii differs from C. appendiculatus in its dwarf habit and other morphological characteristics, and these characteristics are retained under common environmental conditions indicative of genomic differences.

Survival of aerosolized coronavirus in the ambient air

An inactivation of airborne pathogenic Middle East Respiratory Syndrome (MERS-CoV) virus was investigated under controlled laboratory conditions. Two sets of climatic conditions were used in the experiments; (1) representing common office environment (25°C and 79% RH) and (2) climatic conditions of the Middle Eastern region where the virus was originated from (38°C and 24% RH). At the lower temperature, the virus demonstrated high robustness and strong capability to survive with about 63.5% of microorganisms remaining infectious 60min after aerosolisation. Fortunately, virus decay was much stronger for hot and dry air scenario with only 4.7% survival over 60min procedure.

Concurrent Methane Production and Oxidation in Surface Sediment from Aarhus Bay, Denmark.

Marine surface sediments, which are replete with sulfate, are typically considered to be devoid of endogenous methanogenesis. Yet, methanogenic archaea are present in those sediments, suggesting a potential for methanogenesis. We used an isotope dilution method based on sediment bag incubation and spiking with 13C-CH4 to quantify CH4 turnover rates in sediment from Aarhus Bay, Denmark. In two independent experiments, highest CH4 production and oxidation rates (>200 pmol cm-3 d-1) were found in the top 0–2 cm, below which rates dropped below 100 pmol cm-3 d-1 in all other segments down to 16 cm. This drop in overall methane turnover with depth was accompanied by decreasing rates of organic matter mineralization with depth. Molecular analyses based on quantitative PCR and MiSeq sequencing of archaeal 16S rRNA genes showed that the abundance of methanogenic archaea also peaked in the top 0–2 cm segment. Based on the community profiling, hydrogenotrophic and methylotrophic methanogens dominated among the methanogenic archaea in general, suggesting that methanogenesis in surface sediment could be driven by both CO2 reduction and fermentation of methylated compounds. Our results show the existence of elevated methanogenic activity and a dynamic recycling of CH4 at low concentration in sulfate-rich marine surface sediment. Considering the common environmental conditions found in other coastal systems, we speculate that such a cryptic methane cycling can be ubiquitous.

A microclimate model to simulate neutral salt spray testing for corrosion inhibitor evaluation and functional coating development

A microclimate exposure model was developed to simulate the neutral salt spray test (NSS) environment which was used to estimate the pitting corrosion inside an artificial defect of a coating system, when it is exposed to a virtual microclimate. The model uses a dynamic process to simulate salt fog droplet formation, subsequent coalescence, and movement on a coated surface, to determine wet-dry cycles on realistic test samples. While the presented model is formulated to comply with standardised NSS tests, e.g. ASTM B117, the developed method can be tuned to simulate a variety of common cyclic environmental testing conditions, and has wide applicability for the virtual assessment of functional coatings. We will show that when validated against empirical data obtained from inhibitor and pitting studies, the developed model is able to predict the pit growth rate of an AA2024‐T3 aluminium alloy panel placed in a NSS test chamber. We will also explore the adaptation of the model to encompass the virtual assessment of functional coatings such as corrosion inhibiting coatings, and their impact on reducing pitting events and pit growth. This work demonstrates an effective approach for building models and establishing interrelationships with other corrosion models or empirical data to produce a predictive system that could ultimately lead to a rapid methodology for virtually screening new functional coatings and formulations, reducing labour costs and freeing up testing infrastructure for materials validation tasks.

Differential physiological response to sea lamprey parasitism between lake trout (Salvelinus namaycush) morphotypes from Lake Superior

Assessment of stress from varied sources is usually evaluated using individuals derived from a single population and is assumed to represent all populations of that species. However, recent research has identified intraspecies variations in the stress response, which may be mediated by life history. We examined how life history can influence the physiological responses to an acute stress event by evaluating sea lamprey (Petromyzon marinus) parasitism response in two lake trout (Salvelinus namaycush) morphotypes: the lean and the siscowet. The morphotypes differ in that the lean grows faster, is more fecund, and has a shorter life span. In contrast, the siscowet grows slower, is older at maturity, and lives longer. Our study compared long-term parasitism responses between wild leans and siscowets in Lake Superior and immediate responses in laboratory parasitism trials using lake trout reared under common environmental conditions. Leans, but not siscowets, showed changes in steroid-binding protein function and weak evidence of gigantism in response to parasitism. Both morphotypes showed indications of reproductive endocrine alterations in response to parasitism. Our results demonstrate intraspecies variation in physiological stressor response, which is mediated by life history differences that could potentially have differential population implications.

IL-33/ST2 signaling excites sensory neurons and mediates itch response in a mouse model of poison ivy contact allergy

Poison ivy-induced allergic contact dermatitis (ACD) is the most common environmental allergic condition in the United States. Case numbers of poison ivy ACD are increasing due to growing biomass and geographical expansion of poison ivy and increasing content of the allergen, urushiol, likely attributable to rising atmospheric CO2 Severe and treatment-resistant itch is the major complaint of affected patients. However, because of limited clinical data and poorly characterized models, the pruritic mechanisms in poison ivy ACD remain unknown. Here, we aim to identify the mechanisms of itch in a mouse model of poison ivy ACD by transcriptomics, neuronal imaging, and behavioral analysis. Using transcriptome microarray analysis, we identified IL-33 as a key cytokine up-regulated in the inflamed skin of urushiol-challenged mice. We further found that the IL-33 receptor, ST2, is expressed in small to medium-sized dorsal root ganglion (DRG) neurons, including neurons that innervate the skin. IL-33 induces Ca2+ influx into a subset of DRG neurons through neuronal ST2. Neutralizing antibodies against IL-33 or ST2 reduced scratching behavior and skin inflammation in urushiol-challenged mice. Injection of IL-33 into urushiol-challenged skin rapidly exacerbated itch-related scratching via ST2, in a histamine-independent manner. Targeted silencing of neuronal ST2 expression by intrathecal ST2 siRNA delivery significantly attenuated pruritic responses caused by urushiol-induced ACD. These results indicate that IL-33/ST2 signaling is functionally present in primary sensory neurons and contributes to pruritus in poison ivy ACD. Blocking IL-33/ST2 signaling may represent a therapeutic approach to ameliorate itch and skin inflammation related to poison ivy ACD.

Global meta-analysis of native and nonindigenous trophic traits in aquatic ecosystems.

Ecologists have recently devoted their attention to the study of species traits and their role in the establishment and spread of nonindigenous species (NIS). However, research efforts have mostly focused on studies of terrestrial taxa, with lesser attention being dedicated to aquatic species. Aquatic habitats comprise of interconnected waterways, as well as exclusive introduction vectors that allow unparalleled artificial transport of species and their propagules. Consequently, species traits that commonly facilitate biological invasions in terrestrial systems may not be as represented in aquatic environments. We provide a global meta-analysis of studies conducted in both marine and freshwater habitats. We selected studies that conducted experiments with native and NIS under common environmental conditions to allow detailed comparisons among species traits. In addition, we explored whether different factors such as species relatedness, functional feeding groups, latitude, climate, and experimental conditions could be linked to predictive traits. Our results show that species with traits that enhance consumption and growth have a substantially increased probability of establishing and spreading when entering novel ecosystems. Moreover, traits associated with predatory avoidance were more prevalent in NIS and therefore favour invasive species in aquatic habitats. When we analysed NIS interacting with taxonomically distinctive native taxa, we found that consumption and growth were particularly important traits. This suggests that particular attention should be paid to newly introduced species for which there are no close relatives in the local biota. Finally, we found a bias towards studies conducted in temperate regions, and thus, more studies in other climatic regions are needed. We conclude that studies aiming at predicting future range shifts should consider trophic traits of aquatic NIS as these traits are indicative of multiple interacting mechanisms involved in promoting species invasions.

Experimental Evaluation of Structural Steel Coating Systems

AbstractDepartments of transportation (DOTs) currently use the conventional three-coat system as the predominant choice for the corrosion protection of steel bridge structures. Eliminating one step in the coating process could potentially save time and cost associated with lane closures and traffic control costs. This research paper evaluates several two-coat systems based on the zinc-rich primer and polysiloxane topcoat technology. All samples were conditioned and coated in a state-of-the-art, climate-controlled paint booth, simulating common field ENvironmental CONditions (ENCON) (ENCON 1: 25 °C/50% RH, ENCON 2: 10 °C/40%RH, and ENCON 3: 32°C/80% RH). Accelerated weathering tests were performed on 435 coated samples (scribed and unscribed). Regardless of the ENCON considered, the performance of the two-coat system is very comparable to the three-coat system. This coating technology offers much improved performance with quicker set time and better adhesion pull-off strength. Considering its durability an...

Tolerant and Susceptible Sesame Genotypes Reveal Waterlogging Stress Response Patterns

Waterlogging is a common adverse environmental condition that limits plant growth. Sesame (Sesamum indicum) is considered a drought-tolerant oil crop but is typically susceptible to harmful effects from waterlogging. The present study used comparative analysis to explore the waterlogging stress response associated with two sesame genotypes. The RNA-seq dataset generated during a time course of 0, 3, 9 and 15 h of waterlogging as well as 20 h post-drainage indicated that stress gradually suppressed the expression of sesame genes, with 9 h as the critical time point for the response of sesame to waterlogging stress. Of the 19,316 genes expressed during waterlogging, 72.1% were affected significantly. Sesame of both tolerant and susceptible genotypes showed decreased numbers of upregulated differentially expressed genes (DEGs) but increased numbers of downregulated DEGs at the onset of waterlogging. However, the tolerant-genotype sesame exhibited 25.5% more upregulated DEGs and 29.7% fewer downregulated DEGs than those of the susceptible-genotype strain between 3 and 15 h. The results indicated that the tolerant sesame displayed a more positive gene response to waterlogging. A total of 1,379 genes were significantly induced and commonly expressed in sesame under waterlogging conditions from 3 to 15 h regardless of tolerance level; of these genes, 98 are known homologous stress responsive genes, while the remaining 1,281 are newly reported here. This gene set may represent the core genes that function in response to waterlogging, including those related mainly to energy metabolism and phenylpropanoid biosynthesis. Furthermore, a set of 3,016 genes functioning in energy supply and cell repair or formation was activated in sesame recovery from waterlogging stress. A comparative analysis between sesame of the tolerant and susceptible genotypes revealed 66 genes that may be candidates for improving sesame tolerance to waterlogging. This study provided a comprehensive picture of the sesame gene expression pattern in response to waterlogging stress. These results will help dissect the mechanism of the sesame response to waterlogging and identify candidate genes to improve its tolerance.