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"Controlled conditions"
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Lab-scale investigation of the ability of Polar Organic Chemical Integrative Sampler to catch short pesticide contamination peaks
In this lab-scale study, the POCIS capacity to integrate short contamination peaks of variable intensity and duration was evaluated. POCIS were immersed for 14 days in tanks filled with tap water and spiked at different concentrations with 12 pesticides of various polarities (log K
ow
= 1.1–4.7) and classes (herbicides, fungicides, and insecticides). Concentrations were kept relatively constant at 1 μg L
−1
and 5 μg L
−1
, respectively, in two “background” exposure tanks. Three contamination peaks of increasing intensity and decreasing duration were simulated (10 μg L
−1
for 24 h, 40 μg L
−1
for 6 h, and 60 μg L
−1
for 1 h). This lab-scale study demonstrated that ten moderately polar compounds (2 < log K
ow
< 4) showed a linear uptake, as observed in previous studies, while a non-linear model fits the data of the two most polar pesticides (log K
ow
< 2). Depending on chemical polarity, some compounds exhibited a “burst effect” or “lag effect” during the first 3 days of exposure. After 14 days of exposure, contamination peaks appeared integrated for seven compounds, showing the ability of POCIS to catch very short pollution events and to provide acceptable time-weighted average concentration estimates under laboratory-controlled conditions.
Journal Article
Physiological and Immunological Status of Adult Honeybees (Apis mellifera) Fed Sugar Syrup Supplemented with Pentadecapeptide BPC 157
Various factors contribute to a decline in diversity and number of bees. Here, an integrated approach in experimental BPC 157 therapy was implemented, combining laboratory-controlled and field study results. The aim of a study was to assess the effects of BPC 157 additional feeding of newly emerged worker honeybees on few biochemical and immunological parameters in hemolymph (glucose, trehalose, lipids, proteins, vitellogenin, glucose-oxidase (GOX)), and hypopharyngeal gland (HPG), in laboratory-controlled conditions. Additionally, to examine the physiological status of protein digestion, the enzymatic activity of leucine aminopeptidase (LAP) in the mid-guts of worker honeybees was analyzed. It was found that individual honeybees, in hoarding cages, following BPC 157 administration through carbohydrate food, showed positive physiological changes when compared to the control groups. Those results were complemented by strong and visible LAP activity, particularly noticeable in the apical parts of the epithelial cells in the mid-guts of young worker honeybees originated from treated hives, suggesting a link between alternative oral therapy with BPC 157 and honeybees’ immunity.
Journal Article
Correction: Differential seedling responses of chickpea varieties to hexavalent chromium (VI) stress under controlled conditions
[This corrects the article DOI: 10.1371/journal.pone.0341546.].
Journal Article
Analysis of the Corrosion Process with the Application of the Novel Type of Coupon Installation
The corrosion process leads to high power consumption, high maintenance costs and the loss of commercial income during downtime in various branches of industry. The proper methods to measure and forecast the corrosion process would help intervene in process production where corrosion is a common phenomenon. Therefore, the main aim of this experimental study is to improve the widely used corrosion monitoring methods with corrosion coupons. As part of this work, the installation for testing corrosion process under controlled conditions and with the application of mild steel coupons is proposed. The measurement concept is to install the coupons in a stream with the corrosion liquid (these conditions should be controlled). The numerical simulations of the fluid flow in the coupon installation were carried out, and the obtained results in the form of a velocity map allowed us to propose the placement of the coupons in the tested installation in such a way that the flowing liquid evenly washed the coupon surface. The developed coupon installation was tested for aggressive corrosive conditions, which were assessed using the water stability indices (Langelier Saturation Index and Ryznar stability index). Moreover, the inductively coupled plasma optical emission spectroscopy analysis characterised the liquid samples from the tested coupon installation. The corrosion process for the applied conditions was defined based on the corrosion rate of the tested coupons. This process was also confirmed by obtaining the Raman spectrum for the used corrosion coupons. The obtained investigation contributes significantly by developing the novel coupon installation and demonstrating the procedure for testing the corrosion process with the application of coupons. This setup and method might be successfully applied for accelerated laboratory tests.
Journal Article
QTL Mapping of Diffuse Reflectance Indices of Leaves in Hexaploid Bread Wheat (Triticum aestivum L.)
Quantitative trait loci (QTL) mapping of diffuse reflectance indices of laminas in bread wheat (
Triticum aestivum
L.) has been first performed under controlled conditions of a regulated agroecobiological testing ground in the presence or absence of nitrogen fertilizers. Indices chosen for the study determine a range of important characteristics, such as the content of chlorophylls and anthocyanins, carotenoid/chlorophyll ratio, photochemical activity of the photosynthetic apparatus, light scattering on a lamina, assimilating leaf surface area, and grain productivity. In total, 31 QTLs have been mapped. A significant correlation has been revealed between the introduction of a nitrogen fertilizer and the five of six optical characteristics of the photosynthetic apparatus activity in bread wheat. The only exception is the reflectance index for near-infrared radiation (800 nm), which depends on the structural features of leaf tissues. No statistically significant correlation has been revealed between the thousand-grain weight and spectral characteristics of the diffuse reflectance of the lamina measured at the booting stage. However, a significant correlation between the number of grains formed in the spike of the main stalk and the traits characterizing activity of the photosynthetic apparatus (reflectance indices, leaf area) has been observed. Results of the performed variance, correlation, and QTL analyses confirm each other indicating reliability of the revealed effect of nitrogen nutrition level on the manifestation of the studied reflectance indices in bread wheat under strictly controlled conditions of an agroecobiological testing ground. Application of noninvasive optical methods provides a high-throughput assessment of photosynthetic intensity in plants and, therefore, can be used for efficient selection of promising wheat genotypes with high grain productivity under both controlled and field conditions.
Journal Article
Sequencing error profiles of Illumina sequencing instruments
Sequencing technology has achieved great advances in the past decade. Studies have previously shown the quality of specific instruments in controlled conditions. Here, we developed a method able to retroactively determine the error rate of most public sequencing datasets. To do this, we utilized the overlaps between reads that are a feature of many sequencing libraries. With this method, we surveyed 1943 different datasets from seven different sequencing instruments produced by Illumina. We show that among public datasets, the more expensive platforms like HiSeq and NovaSeq have a lower error rate and less variation. But we also discovered that there is great variation within each platform, with the accuracy of a sequencing experiment depending greatly on the experimenter. We show the importance of sequence context, especially the phenomenon where preceding bases bias the following bases toward the same identity. We also show the difference in patterns of sequence bias between instruments. Contrary to expectations based on the underlying chemistry, HiSeq X Ten and NovaSeq 6000 share notable exceptions to the preceding-base bias. Our results demonstrate the importance of the specific circumstances of every sequencing experiment, and the importance of evaluating the quality of each one.
Journal Article
Soil microbiomes show consistent and predictable responses to extreme events
Increasing extreme climatic events threaten the functioning of terrestrial ecosystems
1
,
2
. Because soil microbes govern key biogeochemical processes, understanding their response to climate extremes is crucial in predicting the consequences for ecosystem functioning
3
,
4
. Here we subjected soils from 30 grasslands across Europe to four contrasting extreme climatic events under common controlled conditions (drought, flood, freezing and heat), and compared the response of soil microbial communities and their functioning with those of undisturbed soils. Soil microbiomes exhibited a small, but highly consistent and phylogenetically conserved, response under the imposed extreme events. Heat treatment most strongly impacted soil microbiomes, enhancing dormancy and sporulation genes and decreasing metabolic versatility. Microbiome response to heat in particular could be predicted by local climatic conditions and soil properties, with soils that do not normally experience the extreme conditions being imposed being most vulnerable. Our results suggest that soil microbiomes from different climates share unified responses to extreme climatic events, but that predicting the extent of community change may require knowledge of the local microbiome. These findings advance our understanding of soil microbial responses to extreme events, and provide a first step for making general predictions about the impact of extreme climatic events on soil functioning.
Soils from 30 grasslands across Europe were subjected to 4 contrasting extreme climatic events under drought, flood, freezing and heat conditions, with the results suggesting that soil microbiomes from different climates share unified responses to extreme climatic events.
Journal Article
Abiotic and biotic stress combinations
Environmental stress conditions such as drought, heat, salinity, cold, or pathogen infection can have a devastating impact on plant growth and yield under field conditions. Nevertheless, the effects of these stresses on plants are typically being studied under controlled growth conditions in the laboratory. The field environment is very different from the controlled conditions used in laboratory studies, and often involves the simultaneous exposure of plants to more than one abiotic and/or biotic stress condition, such as a combination of drought and heat, drought and cold, salinity and heat, or any of the major abiotic stresses combined with pathogen infection. Recent studies have revealed that the response of plants to combinations of two or more stress conditions is unique and cannot be directly extrapolated from the response of plants to each of the different stresses applied individually. Moreover, the simultaneous occurrence of different stresses results in a high degree of complexity in plant responses, as the responses to the combined stresses are largely controlled by different, and sometimes opposing, signaling pathways that may interact and inhibit each other. In this review, we will provide an update on recent studies focusing on the response of plants to a combination of different stresses. In particular, we will address how different stress responses are integrated and how they impact plant growth and physiological traits.
Journal Article