Multi-task bioassay pre-training for protein-ligand binding affinity prediction.

Protein-ligand binding affinity (PLBA) prediction is the fundamental task in drug discovery. Recently, various deep learning-based models predict binding affinity by incorporating the three-dimensional (3D) structure of protein-ligand complexes as input and achieving astounding progress. However, due to the scarcity of high-quality training data, the generalization ability of current models is still limited. Although there is a vast amount of affinity data available in large-scale databases such as ChEMBL, issues such as inconsistent affinity measurement labels (i.e. IC50, Ki, Kd), different experimental conditions, and the lack of available 3D binding structures complicate the development of high-precision affinity prediction models using these data. To address these issues, we (i) propose Multi-task Bioassay Pre-training (MBP), a pre-training framework for structure-based PLBA prediction; (ii) construct a pre-training dataset called ChEMBL-Dock with more than 300k experimentally measured affinity labels and about 2.8M docked 3D structures. By introducing multi-task pre-training to treat the prediction of different affinity labels as different tasks and classifying relative rankings between samples from the same bioassay, MBP learns robust and transferrable structural knowledge from our new ChEMBL-Dock dataset with varied and noisy labels. Experiments substantiate the capability of MBP on the structure-based PLBA prediction task. To the best of our knowledge, MBP is the first affinity pre-training model and shows great potential for future development. MBP web-server is now available for free at: https://huggingface.co/spaces/jiaxianustc/mbp.

Absence of lung tumor promotion with reduced tumor size in mice after inhalation of copper welding fumes.

Welding fumes are a Group 1 (carcinogenic to humans) carcinogen as classified by the International Agency for Research on Cancer. The process of welding creates inhalable fumes rich in iron (Fe) that may also contain known carcinogenic metals such as chromium (Cr) and nickel (Ni). Epidemiological evidence has shown that both mild steel (Fe-rich) and stainless steel (Fe-rich + Cr + Ni) welding fume exposure increases lung cancer risk, and experimental animal data support these findings. Copper-nickel (CuNi) welding processes have not been investigated in the context of lung cancer. Cu is intriguing, however, given the role of Cu in carcinogenesis and cancer therapeutics. This study examines the potential for a CuNi fume to induce mechanistic key characteristics of carcinogenesis in vitro and to promote lung tumorigenesis, using a two-stage mouse bioassay, in vivo. Male A/J mice, initiated with 3-methylcholanthrene (MCA; 10 µg/g), were exposed to CuNi fumes or air by whole-body inhalation for 9 weeks (low deposition-LD and high deposition-HD) and then sacrificed at 30 weeks. In BEAS-2B cells, the CuNi fume-induced micronuclei and caused DNA damage as measured by γ-H2AX. The fume exhibited high reactivity and a dose-response in cytotoxicity and oxidative stress. In vivo, MCA/CuNi HD and LD significantly decreased lung tumor size and adenomas. MCA/CuNi HD exposure significantly decreased gross-evaluated tumor number. In summary, the CuNi fume in vitro exhibited characteristics of a carcinogen, but in vivo, the exposure resulted in smaller tumors, fewer adenomas, less hyperplasia severity, and with HD exposure, less overall lung lesions/tumors.

Insights into the whole genome sequence of Bacillus thuringiensis NBAIR BtPl, a strain toxic to the melon fruit fly, Zeugodacus cucurbitae.

Bacillus thuringiensis is the most widely used biopesticide, targets a diversity of insect pests belonging to several orders. However, information regarding the B. thuringiensis strains and toxins targeting Zeugodacus cucurbitae is very limited. Therefore, in the present study, we isolated and identified five indigenous B. thuringiensisstrains toxic to larvae of Z. cucurbitae. However, of five strains NBAIR BtPl displayed the highest mortality (LC50 = 37.3 µg/mL) than reference strain B. thuringiensis var. israelensis (4Q1) (LC50 = 45.41 µg/mL). Therefore, the NBAIR BtPl was considered for whole genome sequencing to identify the cry genes present in it. Whole genome sequencing of our strain revealed genome size of 6.87 Mb with 34.95% GC content. Homology search through the BLAST algorithm revealed that NBAIR BtPl is 99.8% similar to B. thuringiensis serovar tolworthi, and gene prediction through Prokka revealed 7406 genes, 7168 proteins, 5 rRNAs, and 66 tRNAs. BtToxin_Digger analysis of NBAIR BtPl genome revealed four cry gene families: cry1, cry2, cry8Aa1, and cry70Aa1. When tested for the presence of these four cry genes in other indigenous strains, results showed that cry70Aa1 was absent. Thus, the study provided a basis for predicting cry70Aa1 be the possible reason for toxicity. In this study apart from novel genes, we also identified other virulent genes encoding zwittermicin, chitinase, fengycin, and bacillibactin. Thus, the current study aids in predicting potential toxin-encoding genes responsible for toxicity to Z. cucurbitae and thus paves the way for the development of B. thuringiensis-based formulations and transgenic crops for management of dipteran pests.

Host selection by thrips is affected by the floral volatile profile of sunflower.

Thrips, Frankliniella intonsa, is a highly polyphagous pest with a worldwide distribution. F. intonsa-infested sunflower seeds show marked visual damage. The study findings revealed that significantly more F. intonsa infested confection sunflower compared to oilseed sunflower, via olfactometer bioassay studies, we found that compared with the flower and pollen of oilseed sunflowers, those of confection sunflowers attract F. intonsa. Considering this discrepancy in the preference of F. intonsa on oilseed and confection sunflowers, the volatiles of the flower and pollens of two sunflowers were analysed by gas chromatography-mass spectroscopy. The behavioural responses of F. intonsa were assessed for these compounds using Y-tube bioassays. Geranyl bromide, a unique volatile component of oilseed sunflowers, induced an assertive approach-avoidance behaviour in F. intonsa, whereas the unique component ethyl isovalerate in confection sunflowers attracted F. intonsa. F. intonsa adults demonstrated significant attraction to the blends of confection sunflowers. Furthermore, field verification revealed that intercropping confection and oilseed sunflowers could effectively control F. intonsa. The study provided insights into the chemical cues used by F. intonsa in locating hosts. Therefore, oilseed sunflowers can be used as repellent plants to prevent F. intonsa invasion.

A practical guide to the discovery of biomolecules with biostimulant activity.

The growing demand for sustainable solutions in agriculture, which are critical for crop productivity and food quality in the face of climate change and the need to reduce agrochemical usage, has brought biostimulants into the spotlight as valuable tools for regenerative agriculture. With their diverse biological activities, biostimulants can contribute to crop growth, nutrient use efficiency, and abiotic stress resilience, as well as to the restoration of soil health. Biomolecules include humic substances, protein lysates, phenolics, and carbohydrates have undergone thorough investigation because of their demonstrated biostimulant activities. Here, we review the process of the discovery and development of extract-based biostimulants, and propose a practical step-by-step pipeline that starts with initial identification of biomolecules, followed by extraction and isolation, determination of bioactivity, identification of active compound(s), elucidation of mechanisms, formulation, and assessment of effectiveness. The different steps generate a roadmap that aims to expedite the transfer of interdisciplinary knowledge from laboratory-scale studies to pilot-scale production in practical scenarios that are aligned with the prevailing regulatory frameworks.

Discovery of novel CDK2 inhibitors using multistage virtual screening and in vitro melanoma cell lines.

Cyclin-dependent kinases 2 (CDK2) is a serine/threonine-protein kinase, which plays a key role in the regulation of cell cycle and is related to the occurrence and development of melanoma. In this study, we identified potent inhibitors for CDK2 by combining a multistage virtual screening strategy with bioassay validations. The biochemical activity of compounds was validated with ADP-Glo™ Kinase assay in vitro, and the results indicated that the biochemical activity of compound 1 (C1) was better than other selected compounds. Cell viability assay showed that the minimum inhibition concentration of C1 for CDK2 was lower than 4 µM. Further functional test results showed that C1 exerted significant antiproliferative, pro-apoptosis, and anti-migration activity in melanoma cell lines (A375 cells, WM35 cells, and A875 cells). Our findings suggested that the C1, virtually screened from compound libraries, as the novel inhibitor of CDK2, may be further developed as an effective therapeutic agent in the treatment of melanoma lines.

Pharmacokinetic Bioequivalence between Generic and Originator Orally Inhaled Drug Products: Validity of Administration of Doses above the Approved Single Maximum Dose.

Pharmacokinetic bioequivalence of orally inhaled drug products is a critical component of the US FDA's "weight of evidence" approach, and it can serve as the sole indicator of safety and effectiveness of follow-on inhalation products approved in Europe and some other geographic areas. The approved labels of the orally inhaled drug products recommend the maximum number of actuations that can be administered in a single dose on one occasion. This single maximum dose may consist of one or more inhalations depending upon the product. Bioequivalence studies for the inhalation drug product registrations in the US and EU have employed single and multiple actuation doses, in some cases over and above the approved single maximum labeled doses, thus, inconsistent with the approved labeling of the reference products. Pharmacokinetics of inhaled drug products after single and multiple doses may be different, with implications for bioequivalence determined at single and multiple doses. Scientific literature indicates that the relative bioavailability of the Test and Reference products may differ between administrations of doses in one and multiple inhalations. Multiple doses not only alter the pharmacokinetics but also may reduce the sensitivity of the bioassay to actual differences between the Test and Reference product performances. Ability of the pharmacokinetic bioassay to accurately determine the extent of difference between two products may also be substantially reduced at high doses. Therefore, in our opinion, pharmacokinetic bioequivalence to support regulatory approvals of inhalation products at doses above the recommended single maximum dose should be avoided. Furthermore, the bioequivalence of products (if any) established at doses exceeding the approved single maximum doses should be revisited to determine if the products maintain bioequivalence when evaluated at the clinically relevant single maximum doses.

Molecular phylogeny and secondary structure analysis of hop stunt viroid (HSVd) associated with Mulberry (Morus alba) in India.

Hop stunt viroid (HSVd), a small, single stranded, circular, non-coding infectious RNA known to cause infection in various economically important crop plants. In the present investigation, a study was conducted in the southern part of Karnataka districts of India to detect the possible association of HSVd infection in mulberry plants. A total of 41 mulberry plants showing typical viroid-like symptoms along with asymptomatic samples were collected and screened using conventional Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) using a specific set of HSVd-Fw/ HSVd-Re primers. Out of 41 samples, the study confirmed the presence of HSVd in six samples of mulberry collected from Ramanagara (1 sample), Chikkaballapur (3 samples) and Doddaballapura (2 samples) regions with an expected HSVd amplicon size of ∼ 290-300 nucleotides. The mechanical transmission of HSVd was also confirmed on cucumber (cv. Suyo) seedlings through bioassay, which was reconfirmed by RT-PCR. The amplicons were cloned, sequenced, and the representative nucleotide sequences were deposited in the NCBI GenBank. Subsequently, molecular phylogenetic analysis showed that HSVd mulberry isolates from this study were most closely related to grapevine isolates, indicating a common origin. On the other hand, it was shown to belong to a different group from mulberry isolates so far reported from Iran, Italy, Lebanon, and China. The secondary structure analysis of HSVd mulberry Indian isolates exhibited substitutions in the terminal left, pathogenicity, and variable regions compared to those of the Indian grapevine isolates. As far as this study is concerned, HSVd was detected exclusively in some mulberry plants with viral-like symptoms, but the pathogenesis and symptom expression needs to be further investigated to establish the relationship between HSVd and the disease symptoms in the mulberry plants.

Allelochemical root-growth inhibitors in low-molecular-weight cress-seed exudate.

BACKGROUND AND AIMS: Cress seeds release allelochemicals that over-stimulate the elongation of hypocotyls of neighbouring (potentially competing) seedlings and inhibit their root growth. The hypocotyl promoter is potassium, but the root inhibitor was unidentified; its nature is investigated here. METHODS: Low-molecular-weight cress-seed exudate (LCSE) from imbibed Lepidium sativum seeds was fractionated by phase partitioning, paper chromatography, high-voltage electrophoresis and gel-permeation chromatography (on Bio-Gel P-2). Fractions, compared with pure potassium salts, were bioassayed for effects on Amaranthus caudatus seedling growth in the dark for 4 days. KEY RESULTS: The LCSE robustly promoted amaranth hypocotyl elongation and inhibited root growth. The hypocotyl inhibitor was non-volatile, hot acid stable, hydrophilic and resistant to incineration, as expected for K+. The root inhibitor(s) had similar properties but were organic (activity lost on incineration). The root inhibitor(s) remained in the aqueous phase (at pH 2.0, 6.5 and 9.0) when partitioned against butan-1-ol or toluene, and were thus hydrophilic. Activity was diminished after electrophoresis, but the remaining root inhibitors were neutral. They became undetectable after paper chromatography; therefore, they probably comprised multiple compounds, which separated from each other, in part, during fractionation. On gel-permeation chromatography, the root inhibitor co-eluted with hexoses. CONCLUSIONS: Cress-seed allelochemicals inhibiting root growth are different from the agent (K+) that over-stimulates hypocotyl elongation and the former probably comprise a mixture of small, non-volatile, hydrophilic, organic substances. Abundant components identified chromatographically and by electrophoresis in cress-seed exudate fitting this description include glucose, fructose, sucrose and galacturonic acid. However, none of these sugars co-chromatographed and co-electrophoresed with the root-inhibitory principle of LCSE, and none of them (in pure form at naturally occurring concentrations) inhibited root growth. We conclude that the root-inhibiting allelochemicals of cress-seed exudate remain unidentified.

Compound isolation through bioassay-guided fractionation of Tectona grandis leaf extract against Vibrio pathogens in shrimp.

Tectona grandis Linn, commonly known as teak, is traditionally used to treat a range of diseases, including the common cold, headaches, bronchitis, scabies, diabetes, inflammation, and others. The present study was conducted with the purpose of isolating and identifying the active compounds in T. grandis leaf against a panel of Vibrio spp., which may induce vibriosis in shrimp, using bioassay-guided purification. The antimicrobial activity was assessed using the microdilution method, followed by the brine shrimp lethality assay to determine toxicity. Following an initial screening with a number of different solvents, it was established that the acetone extract was the most effective. The acetone extract was then exposed to silica gel chromatography followed by reversed-phase HPLC and further UHPLC-orbitrap-ion trap mass spectrometry to identify the active compounds. Three compounds called 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, deoxyanserinone B, and khatmiamycin were identified with substantial anti-microbial action against V. parahaemolyticus, V. alginolyticus, V. harveyi, V. anguillarum, and V. vulnificus. The IC50 values of the three compounds viz. 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, deoxyanserinone B, and khatmiamycin varied between 2 and 28, 7 and 38, and 7 and 56 µg/mL, respectively, which are as good as the standard antibiotics such as amoxicillin and others. The in vivo toxicity test revealed that the compounds were non-toxic to shrimp. The results of the study suggest that T. grandis leaf can be used as a source of bioactive compounds to treat Vibrio species in shrimp farming.

Combining Passive Sampling and Dosing to Unravel the Contribution of Hydrophobic Organic Contaminants to Sediment Ecotoxicity.

Contaminated sediments are ubiquitous repositories of pollutants and cause substantial environmental risks. Results of sediment bioassays remain difficult to interpret, however, as observed effects may be caused by a variety of (un)known stressors. This study aimed therefore to isolate the effects of hydrophobic organic contaminants from other (non)chemical stressors present in contaminated sediments, by employing a newly developed passive sampling-passive dosing (PSPD) test. The results showed that equilibrium partitioning between pesticides or polyaromatic hydrocarbons (PAHs) in contaminated sediments and a silicone rubber (SR) passive sampler was achieved after 1-3 days. Chlorpyrifos concentrations in pore water of spiked sediment matched very well with concentrations released from the SR into an aqueous test medium, showing that SR can serve as a passive dosing device. Subjecting the 96 h PSPD laboratory bioassay with nonbiting midge (Chironomus riparius) larvae to field-collected sediments showed that at two locations, concentrations of the hydrophobic organic contaminant mixtures were high enough to affect the test organisms. In conclusion, the developed PSPD test was able to isolate the effects of hydrophobic organic contaminants and provides a promising simplified building block for a suite of PSPD tests that after further validation could be used to unravel the contribution of hydrophobic organic chemicals to sediment ecotoxicity.

Towards non-target proactive food safety: identification of active compounds in convenience tomato products by ten-dimensional hyphenation with integrated simulated gastrointestinal digestion.

Current strategies for non-target food screening focus mainly on known hazardous chemicals (adulterants, residues, contaminants, packaging migrants, etc.) instead of bioactive constituents in general and exclude the biological effect detection. To widen the perspective, a more proactive non-target effect-directed strategy is introduced to complement food safety in order to detect not only known but also unknown bioactive compounds. The developed 10-dimensional hyphenation included on-surface digestion (1D), planar chromatographic separation (2D), visualization using white light (3D), UV light (4D), fluorescence light (5D), effect-directed assay analysis (6D), heart-cut zone elution to an orthogonal reversed phase column chromatography including online desalting (7D) with subsequent diode array detection (8D), high-resolution mass spectrometry (9D), and fragmentation (10D). Metabolism, i.e., intestinal digestion of each sample, was simulated and integrated on the same adsorbent surface to study any changes in the compound profiles. As proof of principle, nine convenience tomato products and a freshly prepared tomato soup were screened via five different planar assays in a non-targeted mode. Non-digested and digested samples were compared side by side. In their effect-directed profiles, 14 bioactive compounds from classes of lipids, plant hormones, spices, and pesticides were identified. In particular, bioactive compounds coming from the lipid class were increased by gastrointestinal digestion, while spices and pesticides remained unaffected. With regard to food safety, the determination of the two dinitrophenol herbicides dinoterb and dinoseb in highly processed tomato products should be given special attention. The hyphenation covered a broad analyte spectrum and showed robust and reliable results.

Niche construction and niche choice by aphids infesting wheat ears.

The niche of aphids is largely defined by their consumption of plant phloem sap and its composition, including nutrients and specialized metabolites. Niche construction is the change of the environment by organisms, which may influence the fitness of these organisms and their offspring. To better understand interactions between plants and aphids, it is necessary to investigate whether aphids modify the chemical composition of the phloem sap of their host plants and whether conspecifics are affected by previous infestation. In the current study, ears of wheat (Triticum aestivum) plants were infested with clonal lineages of the English grain aphid (Sitobion avenae) or were left uninfested. The metabolic composition of ear phloem sap exudates was analyzed through amino acid profiling and metabolic fingerprinting. Aphids of the clonal lineages were either put on previously aphid-infested or on uninfested ears and their colony sizes followed over time. Furthermore, it was investigated whether aphids choose one treatment group over another. Sitobion avenae infestation affected the relative concentrations of some metabolites in the phloem exudates of the ears. Compared to uninfested plants, the relative concentration of asparagine was higher after aphid infestation. Colonies grew significantly larger on previously aphid-infested ears, which the aphids also clearly chose in the choice experiment. The pronounced positive effect of previous infestation on aphid colonies indicates niche construction, while the choice of these constructed niches reveals niche choice by S. avenae on wheat. The interplay between these different niche realization processes highlights the complexity of interactions between aphids and their hosts.

Attractancy of a Sesquiterpene, ß-caryophyllene to Males of the Oriental Fruit Fly, Bactrocera dorsalis (Diptera: Tephritidae).

The recent discovery of a sesquiterpene, ß-caryophyllene (CP) as a male attractant of the guava fruit fly, Bactrocera correcta (Bezzi) (Diptera: Tephritidae) prompted investigations into the attractancy of CP to the Oriental fruit fly, B. dorsalis (Hendel). This is because males of both species of fruit flies are attracted to, and feed on a phenylpropanoid compound, methyl eugenol (ME). Although CP was a more potent attractant than ME for B. correcta, it is not known if males of B. dorsalis are also attracted to CP. The possible attraction of B. dorsalis to CP as a sesquiterpene may indicate its wide host range through its attraction to different groups of plant volatiles i.e., phenylpropanoids and sesquiterpenes. In this paper, we report that males of B. dorsalis were also attracted to, and feed on CP. Subsequently, we conducted a probit regression analysis to determine the quantal response of sexually mature male flies that were attracted to CP in cage bioassays. Therefore, as a measure of male B. dorsalis' sensitivity of CP, the median dose of CP required to elicit a positive response in 50% of the tested B. dorsalis population (ED50) was calculated as 3.7 mg. This value was over 10,000x higher than known ED50 of B. dorsalis' male attraction ME (between 171 and 268 ng). We propose that the attraction of male B. dorsalis flies to CP was much weaker than to ME. Further, we suggest that in any fruit fly surveillance and monitoring programme, application of lures must consider the specificity and potency of each compound to target fruit fly species. The probit regression analysis of male fly quantal response to lure offers such information.

Comparative Responses of Two Major Cucurbit Pests, Zeugodacus cucurbitae and Zeugodacus tau to Phenylbutanoid Male Lures.

Zeugodacus cucurbitae and Z. tau are two major fruit fly pests of cucurbitaceous plants in the tropical and subtropical regions. The former species has a broader host range and wider world distribution than the latter. With global climate change, Z. tau shows great potential for geographical expansion with several invasion records in recent years. Males of both species are attracted to cue lure (CL) (and raspberry ketone (RK), a deacetyl derivative of CL), a common male lure used in fruit fly population detection, monitoring and control programs. Males of both species are also known to respond to zingerone (ZN), which are produced by some rainforest orchids. Previous studies have shown that fruit fly-male lure interactions are unique to species and lure types, and significantly impact the success of a lure-based fruit fly control program. We seek to compare the attraction of Z. cucurbitae and Z. tau males to CL, RK and ZN via Probit behavioral assays. Our results showed that CL is more attractive to Z. cucurbitae and Z. tau males than RK, while ZN is a poor lure for both species. Attraction Z. tau to CL is slightly lower than Z. cucurbitae, but the former is at least 1.71 times less attractive to RK than the latter. Together with published information on species' sexual development, our current study indicates a lure-based control program via male annihilation technique for Z. tau will be more challenging than Z. cucurbitae and should incorporate other integrated pest management strategies for a desirable outcome.

Kairomonal Effect of Hexane Extracts of Corcyra cephalonica and Spodoptera frugiperda on the Parasitizing Activity of Trichogramma pretiosum.

Egg parasitoids, particularly Trichogrammatidae, play a crucial role in global biocontrol efforts. Their behavior is influenced by chemicals emitted by their hosts, such as kairomones. Among them, Trichogramma pretiosum (Riley) (Hym.; Trichogrammatidae) shows promise as a biocontrol agent on destructive Fall Armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lep.; Noctuidae). Given the invasiveness and widespread impact of FAW, early-stage prevention in the field is imperative. This study aimed to assess the potential of host insects viz.,Corcyra cephalonica (Stainton) (Lep.; Pyralidae) and S. frugiperda kairomones in optimizing the performance of T. pretiosum while parasitizing S. frugiperda. The top two hexane extracts from each host insect were also sent to JNU, AIRF in New Delhi for detailed GC-MS analysis. A four-armed olfactometer was developed to track the movements of T. pretiosum and validated with olfactory cues. Laboratory bioassays revealed that extracts from C. cephalonica and S. frugiperda eggs and moths effectively enhanced the performance of T. pretiosum. Optimal concentrations were determined through Petri dish bioassays, with C1 (10%) concentration of C. cephalonica eggs extract showing the highest Parasitoid Activity Index (PAI), percent parasitization, and adult emergence. Meanwhile, C2 (1%) concentration of S. frugiperda female extract exhibited the highest parasitization percentage and adult emergence. Further assessments in a polyhouse setting demonstrated that treated egg cards positioned 1 m from the release point achieved the highest mean percentage parasitization. Chemical composition analysis via GC-MS revealed that distinctive hydrocarbon and alcohol profiles in the extracts, suggesting their potential for manipulating parasitoid activity in biocontrol efforts. In the S. frugiperda female extract, 12 hydrocarbons and 3 alcohol groups were identified, with tetracontane as the predominant hydrocarbon compound followed by octane, heneicosane, and others. Meanwhile, the C. cephalonica egg extract displayed 9 hydrocarbons and 1 alcohol group, with dodecane leading in area percentage among the hydrocarbons followed by decane, nonane and others. The outputs of current study highlighted that T. pretiosum's utilization of kairomones from C. cephalonica and S. frugiperda, enhancing its search behavior for host eggs. The identification and synthesis of these kairomonal compounds have the potential to revolutionize pest management, emphasizing the role of kairomones in empowering natural predators and parasitoids for sustainable agriculture.

Effects of diluted effluent on aquatic macroinvertebrate communities at the McClean Lake uranium operation in northern Saskatchewan.

Diluted treated effluent from the McClean Lake uranium mill in northern Saskatchewan is released into Vulture Lake, which flows into the east basin of McClean Lake; this input could potentially cause a variety of disturbances to the aquatic systems. This study aimed to determine the potential effects of diluted effluent exposure (metals and major ions) on benthic macroinvertebrates in Vulture Lake and McClean Lake. Two monitoring locations located in Vulture Lake and eight in McClean Lake were used for collection water, sediment, and benthic macroinvertebrates. Complementary surface water bioassays were performed with larvae of the midge Chironomus dilutus using lake water from selected sites. Results indicated that total macroinvertebrate abundance and Margalef index (MI) did not follow the diluted effluent pattern. In addition, while the MI from artificial substrate samplers showed higher values in Vulture Lake and lower values at McClean Lake sites 4 and 5 (closer to effluent diffuser), the values recorded for sediment grab samples registered lower indices in Vulture Lake and higher values for sites 4 and 5. The final model from a Generalized Additive Modelling (GAM) approach suggested that electrical conductivity (EC), selenium (Se), and chloride (Cl) in water, and total organic carbon (TOC) and cadmium (Cd) in sediment are key variables that collectively may have influenced macroinvertebrate community composition at the study sites. Finally, across all test endpoints in the bioassays, exposure to lake water from Vulture Lake and McClean Lake had no statistically significant effects on C. dilutus.

Nonlinear Regression Modelling: A Primer with Applications and Caveats.

Use of nonlinear statistical methods and models are ubiquitous in scientific research. However, these methods may not be fully understood, and as demonstrated here, commonly-reported parameter p-values and confidence intervals may be inaccurate. The gentle introduction to nonlinear regression modelling and comprehensive illustrations given here provides applied researchers with the needed overview and tools to appreciate the nuances and breadth of these important methods. Since these methods build upon topics covered in first and second courses in applied statistics and predictive modelling, the target audience includes practitioners and students alike. To guide practitioners, we summarize, illustrate, develop, and extend nonlinear modelling methods, and underscore caveats of Wald statistics using basic illustrations and give key reasons for preferring likelihood methods. Parameter profiling in multiparameter models and exact or near-exact versus approximate likelihood methods are discussed and curvature measures are connected with the failure of the Wald approximations regularly used in statistical software. The discussion in the main paper has been kept at an introductory level and it can be covered on a first reading; additional details given in the Appendices can be worked through upon further study. The associated online Supplementary Information also provides the data and R computer code which can be easily adapted to aid researchers to fit nonlinear models to their data.

Single-atom nanozymes shines diagnostics of gastrointestinal diseases.

Various clinical symptoms of digestive system, such as infectious, inflammatory, and malignant disorders, have a profound impact on the quality of life and overall health of patients. Therefore, the chase for more potent medicines is both highly significant and urgent. Nanozymes, a novel class of nanomaterials, amalgamate the biological properties of nanomaterials with the catalytic activity of enzymes, and have been engineered for various biomedical applications, including complex gastrointestinal diseases (GI). Particularly, because of their distinctive metal coordination structure and ability to maximize atom use efficiency, single-atom nanozymes (SAzymes) with atomically scattered metal centers are becoming a more viable substitute for natural enzymes. Traditional nanozyme design strategies are no longer able to meet the current requirements for efficient and diverse SAzymes design due to the diversification and complexity of preparation processes. As a result, this review emphasizes the design concept and the synthesis strategy of SAzymes, and corresponding bioenzyme-like activities, such as superoxide dismutase (SOD), peroxidase (POD), oxidase (OXD), catalase (CAT), and glutathione peroxidase (GPx). Then the various application of SAzymes in GI illnesses are summarized, which should encourage further research into nanozymes to achieve better application characteristics.

Efficient discovery of active isolates from Dioscorea spongiosa by the combination of bioassay-guided macroporous resin column chromatography and high-speed counter-current chromatography.

In the present study, twelve compounds from Dioscorea spongiosa were successfully purified by an efficient technique combined bioassay-guided fractionation macroporous resin column chromatography (MRCC) pretreatment and high-speed counter-current chromatography (HSCCC) separation for the first time. Then, D101 MRCC was used to fractionate the crude extract into five parts, which further applied the bioassay-guided fractionation strategy to screen the active fractions of 2 and 4. As for the separation, 200 mg Fr.2 was purified by HSCCC using EtOAc/n-BuOH/H2 O (2:2:3, v/v), leading to annulatomarin (1), dioscoresides C (2), diosniponol C (3), methyl protodioscin (4), pseudoprotodioscin (5), protogracillin (6), as well as 200 mg Fr.4 yielding montroumarin (7), dioscorone A (8), diosniponol D (9), protodioscin (10), gracillin (11), and dioscin (12) using CH2 Cl2 /MeOH/H2 O (3:3:2, v/v) with the purities over 95.0%. Finally, the isolates were assayed for their anti-inflammatory, urico-lowering, and anti-diabetic activities in vitro, which indicated that the steroidal saponins of 5, 6, and 11 showed all these three activities.