Rapid Screening Method Research Articles

Novel helix loop-mediated isothermal amplification (HAMP) assay for colorimetric detection of Staphylococcus aureus in milk.

Staphylococcus aureus is an important and leading cause of foodborne diseases worldwide. Prompt detection and recall of contaminated foods are crucial to prevent untoward health consequences caused by S. aureus. Helix loop-mediated isothermal amplification (HAMP) is an exciting recent addition to the array of available isothermal-based nucleic acid amplification techniques. This study aimed to develop and evaluate a HAMP assay for detecting S. aureus in milk and milk products. The assay is completed in 75 minutes of isothermal temperature incubation (64 ˚C) and dye-based visual interpretation of results based on colour change. The specificity of the developed assay was ascertained using 27 S. aureus and 17 non S. aureus bacterial strains. The analytical sensitivity of the developed HAMP assay was 9.7fg/µL of pure S. aureus DNA. The detection limit of the HAMP assay in milk (86 CFU/mL) was 1000x greater than the routinely used endpoint PCR (86 × 103 CFU/mL). The practicality of applying the HAMP assay was also assessed by analysing milk and milk product samples (n = 95) obtained from different dairy farms and retail outlets. The developed test is a more rapid, sensitive, and user-friendly method for the high-throughput screening of S. aureus in food samples and may therefore be suitable for field laboratories. To our knowledge, this is the first study to develop and evaluate the HAMP platform for detecting S. aureus.

Human mRNA in saliva can correctly identify individuals harboring acute infection.

There are a variety of clinical and laboratory criteria available to clinicians in controlled healthcare settings to help them identify whether an infectious disease is present. However, in situations such as a new epidemic caused by an unknown infectious agent, in health screening contexts performed within communities and outside of healthcare facilities or in battlefield or potential biowarfare situations, this gets more difficult. Pathogen-agnostic methods for rapid screening and triage of large numbers of people for infection status are needed, in particular methods that might work on an easily accessible biospecimen like saliva. Here, we identify a small, core set of approximately 70 human genes whose transcripts serve as saliva-based biomarkers of infection in the human body, in a way that is agnostic to the specific pathogen causing infection.

A fine 3d transition metal regulation strategy toward high-entropy alloy mesoporous nanotubes as efficient electrocatalysts

High-entropy alloys (HEAs) are attracting considerable attention because of their interesting catalytic features, intrinsic thermodynamic stability and diversity of components. Nevertheless, the precise shaping low-dimensional architectures and fine-regulated catalytic performance are still challenging for HEAs. Herein, we propose a cost-effective general template-triggered method to prepare a class of quinary to septenary HEA mesoporous nanotubes (HEA mNTs). In particular, we explore the electron structure–activity relationship toward HEA mNTs with different 3d transition metal regulation by experiments and DFT calculations. As a proof of demonstration, Fe-regulated senary HEA mNTs (PtPdRuIrFeCu mNTs) with ∼1.5 nm wall experimentally unveil the excellent mass activity of 1.94 A/mgPt (1.22 A/mgnoble metals) @ 0.9 VRHE for ORR, which is 7.46- (5.30-) fold higher than commercial Pt/C in 0.1 M KOH. Density functional theory results further reveal that the differential oxygen adsorption energy (EO) of PtPdRuIrFeCu is closest to the theoretical optimal EO, corresponding to excellent ORR activity. Additionally, the linear relationship between the differential EO of HEA and the d band center of pure metals can provide a rapid screening method for HEA catalysts. HEA mNTs reported in this work are a class of prospective catalysts for the fuel cells and water splitting devices, and the would-be applications in sensors and energy storages look bright because of their charming characteristics.

Antitumor activity of urease-free l-asparaginase with low glutaminase coactivity produced by marine-derived Aspergillus flavus

l-asparaginase, which has a high therapeutic effect in various cancer diseases, hydrolyzes l-asparagine to aspartate and ammonia and is mainly used in treating Acute Lymphoblastic Leukaemia. This study aims to investigate the l-asparaginase production potential of marine filamentous fungi and the partial purification and characterization of the l-asparaginase. The rapid plate screening method was used to measure the l-asparaginase activity of 94 marine fungi. l-asparaginase producers were then screened for glutaminase and urease activity. The selected extracellular l-asparaginase producer, Aspergillus flavus MF10, showed 2.82 U/mL l-asparaginase activity in small-scale fermentation. l-asparaginase was concentrated by ultrafiltration followed by acetone precipitation. The specific activity of the enzyme, purified 4,8 fold by partial purification, was determined as 259 U/mg. There were no urease and glutaminase activities in the fermentation broth, but low glutaminase activity (1.27 U/mL) was detected in the concentrated fermentation broth. The optimum pH and temperature of the l-asparaginase were 8.0 and 40 °C, respectively. l-asparaginase was stable at pH 7.0–8.0 and can maintain its activity at 70% at 40 °C after 1 h. While the enzyme decreased the viability of SH-SY5Y (neuroblastoma) to 43% and LNCap (prostate cancer) to 61%, it did not show cytotoxic effects in healthy cell line L929 (fibroblast). It was also determined that l-asparaginase showed low cytotoxicity in HaCaT (keratinocyte) cells. In conclusion, it was shown that urease-free l-asparaginase with low glutaminase coactivity, produced from marine-derived A. flavus MF10, has the potential for medical use.

Screening COVID-19 by Swaasa AI platform using cough sounds: a cross-sectional study

The Advent of Artificial Intelligence (AI) has led to the use of auditory data for detecting various diseases, including COVID-19. SARS-CoV-2 infection has claimed more than six million lives to date and therefore, needs a robust screening technique to control the disease spread. In the present study we created and validated the Swaasa AI platform, which uses the signature cough sound and symptoms presented by patients to screen and prioritize COVID-19 patients. We collected cough data from 234 COVID-19 suspects to validate our Convolutional Neural Network (CNN) architecture and Feedforward Artificial Neural Network (FFANN) (tabular features) based algorithm. The final output from both models was combined to predict the likelihood of having the disease. During the clinical validation phase, our model showed a 75.54% accuracy rate in detecting the likely presence of COVID-19, with 95.45% sensitivity and 73.46% specificity. We conducted pilot testing on 183 presumptive COVID subjects, of which 58 were truly COVID-19 positive, resulting in a Positive Predictive Value of 70.73%. Due to the high cost and technical expertise required for currently available rapid screening methods, there is a need for a cost-effective and remote monitoring tool that can serve as a preliminary screening method for potential COVID-19 subjects. Therefore, Swaasa would be highly beneficial in detecting the disease and could have a significant impact in reducing its spread.

A rapid semi-quantitative screening method to assess chemicals present in heated e-liquids and e-cigarette aerosols

Abstract. ​​​​​​​Electronic cigarettes (e-cigarettes) lack regulatory status as therapeutic products in all jurisdictions worldwide. They are potentially unsafe consumer products, with significant evidence they pose a risk to human health. Therefore, developing rapid, economical test methods to assess the chemical composition of e-liquids in heated and unheated forms and the aerosols produced by e-cigarettes is crucial. Four different e-liquids were heated using two different methods: (1) “typical” vaping using an e-cigarette device, by cycling “on” for 3 s every minute for 2 h (e-liquid obtained from remainder in the tank and aerosol collected in an impinger), and (2) “accelerated” heating, using an e-cigarette coil submerged in e-liquid and heating in short 20 s bursts on then 20 s off for 2 min only (liquid traps aerosol produced). All e-liquids were then analysed to test for the presence and quantity of 13 chemicals by gas chromatography–mass spectrometry and compared to an unheated sample. E-liquids heated with the accelerated method showed a comparable trend to the typical heating method, i.e. increase or decrease in chemical compound quantity, for more than two-thirds of the detected compounds analysed over all e-liquids. Six chemicals were detected as aerosol from the impinger fluid with the typical heating method at negligible levels. We propose that this accelerated version of the typical vaping method could form the basis of a standardized screening tool to test heated e-liquids (and e-cigarette aerosols) for harmful or banned substances. This will ensure that only approved products reach the consumer and reduce potential e-cigarette harm.

A multi-objective bi-level task planning strategy for UUV target visitation in ocean environment

Unmanned underwater vehicle (UUV) is commonly utilized for ocean resource exploration. To effectively plan long-term tasks, it is crucial to consider energy usage and task quality. This paper proposes a multi-objective bi-level task planning strategy (MOBTPS) for solving an UUV dispatched to visit a set of targets. On the one hand, rapid initialization screening method based on task quality is adopted. On the other hand, to address the challenge of black-box optimization for UUV task time, a nested optimization approach is employed. The upper level of optimization focuses on determining the shortest access order for the tasks, while the lower level optimizes the route between the task points. The Simulated Annealing (SA) and Genetic Algorithm (GA) are selected for simultaneous optimization of task assignment and path planning. In order to adapt to varying ocean currents, an UUV control strategy is incorporated into the path planning process. The optimal solution is obtained by using the criteria importance through intercriteria correlation (CRITIC) method. The effectiveness of MOBTPS is demonstrated through extensive numerical simulations.

Obtaining New Candidate Peptides for Biological Anticancer Drugs from Enzymatic Hydrolysis of Human and Bovine Hemoglobin.

Enzymatic hydrolysis of bovine and human hemoglobin generates a diversity of bioactive peptides, mainly recognized for their antimicrobial properties. However, antimicrobial peptides stand out for their ability to specifically target cancer cells while preserving rapidly proliferating healthy cells. This study focuses on the production of bioactive peptides from hemoglobin and evaluates their anticancer potential using two distinct approaches. The first approach is based on the use of a rapid screening method aimed at blocking host cell protein synthesis to evaluate candidate anticancer peptides, using Lepidium sativum seed germination as an indicator. The results show that: (1) The degree of hydrolysis (DH) significantly influences the production of bioactive peptides. DH levels of 3 to 10% produce a considerably stronger inhibition of radicle growth than DH 0 (the native form of hemoglobin), with an intensity three to four times greater. (2) Certain peptide fractions of bovine hemoglobin have a higher activity than those of human hemoglobin. (3) The structural characteristics of peptides (random coil or alpha helix) play a crucial role in the biological effects observed. (4) The α137-141 peptide, the target of the study, was the most active of the fractions obtained from bovine hemoglobin (IC50 = 29 ± 1 µg/mL) and human hemoglobin (IC50 = 48 ± 2 µg/mL), proving to be 10 to 15 times more potent than the other hemoglobin fractions, attributed to its strong antimicrobial potential. The second approach to assessing anticancer activity is based on the preliminary in vitro analysis of hydrolysates and their peptide fractions, with a focus on the eL42 protein. This protein is of major interest due to its overexpression in all cancer cells, making it an attractive potential target for the development of anticancer molecules. With this in mind, astudy was undertaken using a method for labeling formylase (formyl-methionyl-tRNA transformylase (FMTS)) with oxidized tRNA. This approach was chosen because of the similarities in the interaction between formylase and the eL42 protein with oxidized tRNA. The results obtained not only confirmed the previous conclusions but also reinforced the hypothesis that the inhibition of protein synthesis plays a key role in the anticancer mechanism of these peptides. Indeed, the data suggest that samples containing α137-141 peptide (NKT) and total hydrolysates may have modulatory effects on the interaction between FMTS and oxidized tRNA. This observation highlights the possibility that the latter could influence molecular binding mechanisms, potentially resulting in a competitive situation where the ability of substrate tRNA to bind efficiently to ribosomal protein is compromised in their presence. Ultimately, these results suggest the feasibility of obtaining candidate peptides for biological anticancer drugs from both human and bovine hemoglobin sources. These scientific advances show new hope in the fight against cancer, which affects a large number of people around the world.

Fluorescence “turn-on” sensing for five PDE5 inhibitors in functional food based on bimetallic nanoclusters

Some phosphodiesterase type-5 (PDE5) inhibitors are active ingredients of prescription drugs that are widely used in the treatment of erectile dysfunction (ED). Recently, a large number of substances with this activity have been developed. Illegal addition of PDE5 inhibitors to foods could lead to cardiovascular diseases and even death, which poses a serious threat to food safety, therefore an on-site rapid screening method is urgently needed. Herein, a host functionalized bimetallic nanoclusters, CD/Au Ag NCs, were synthesized through self-assembly of 6-Aza-2-thiothymine gold nanoclusters (ATT-Au NCs), Arginine silver nanoclusters (Arg-Ag NCs) and carboxymethyl β-cyclodextrin (β-CMCD). The introduction of Rhodamine 6G (R6G) could quench the fluorescence of CD/Au Ag NCs based on the inner filter effect (IFE) and fluorescence resonance energy transfer effect (FRET). Importantly, it was discovered that several PDE5 inhibitors exhibited a higher binding affinity to β-CMCD and could displace R6G binding with CD cavity, which disrupted the fluorescence quenching effects and resulted in the fluorescence recovery of CD/Au Ag NCs. This fluorescence turn-on signal could be utilized for the detection of PDE5 inhibitors. At present, emerging PDE5 inhibitor analogues pose a great challenge to food safety due to their unknown efficacy and safety. The proposed method holds the advantages of high sensitivity, simple probe synthesis, easy operation, and simultaneous detection of multiple PDE5 inhibitors. Meanwhile, the successful application in functional food sample demonstrated its high application potential in multiple PDE5 inhibitors screening.

Research on a New Intelligent and Rapid Screening Method for Depression Risk in Young People Based on Eye Tracking Technology.

Depression is a prevalent mental disorder, with young people being particularly vulnerable to it. Therefore, we propose a new intelligent and rapid screening method for depression risk in young people based on eye tracking technology. We hypothesized that the "emotional perception of eye movement" could characterize defects in emotional perception, recognition, processing, and regulation in young people at high risk for depression. Based on this hypothesis, we designed the "eye movement emotional perception evaluation paradigm" and extracted digital biomarkers that could objectively and accurately evaluate "facial feature perception" and "facial emotional perception" characteristics of young people at high risk of depression. Using stepwise regression analysis, we identified seven digital biomarkers that could characterize emotional perception, recognition, processing, and regulation deficiencies in young people at high risk for depression. The combined effectiveness of an early warning can reach 0.974. Our proposed technique for rapid screening has significant advantages, including high speed, high early warning efficiency, low cost, and high intelligence. This new method provides a new approach to help effectively screen high-risk individuals for depression.

Simultaneously Determined Antioxidant and Pro-Oxidant Activity of Randomly Selected Plant Secondary Metabolites and Plant Extracts.

Oxidative stress is a well-known phenomenon arising from physiological and nonphysiological factors, defined by the balance between antioxidants and pro-oxidants. While the presence and uptake of antioxidants are crucial, the pro-oxidant effects have not received sufficient research attention. Several methods for assessing pro-oxidant activity, utilizing various mechanisms, have been published. In this paper, we introduce a methodology for the simultaneous determination of antioxidant and pro-oxidant activity on a single microplate in situ, assuming that the FRAP method can measure both antioxidant and pro-oxidant activity due to the generation of pro-oxidant Fe2+ ions in the Fenton reaction. Systematic research using this rapid screening method may help to distinguish between compounds with dominant antioxidant efficacy and those with dominant pro-oxidant effects. Our preliminary study has revealed a dominant pro-oxidant effect for compounds with a higher number of oxygen heteroatoms, especially sp2 hybridized compounds (such as those containing keto groups), such as flavonoids and plant extracts rich in these structural types. Conversely, catechins, carotenoids, and surprisingly, extracts from birch leaves and chestnut leaves have demonstrated dominant antioxidant activity over pro-oxidant. These initial findings have sparked significant interest in the systematic evaluation of a more extensive collection of compounds and plant extracts using the developed method.

Real-Time Detection of Dynamic Affinity between Biomolecules Using Surface Plasmon Resonance (SPR) Technology.

Surface plasmon resonance (SPR) technology is a sensitive precise method for detecting viruses, pathogenic molecular proteins, and receptors, determining blood types, and detecting food adulteration, among other biomolecular detections. This technology allows for the rapid identification of potential binding between biomolecules, facilitating fast and user-friendly, non-invasive screening of various indicators without the need for labeling. Additionally, SPR technology facilitates real-time detection for high-throughput drug screening. In this program, the application field and basic principles of SPR technology are briefly introduced. The operation process is outlined in detail, starting with instrument calibration and basic system operation, followed by ligand capture and multi-cycle analysis of the analyte. The real-time curve and experimental results of binding quercetin and calycosin to KCNJ2 protein were elaborated upon. Overall, SPR technology provides a highly specific, simple, sensitive, and rapid method for drug screening, real-time detection of related pharmacokinetics, virus detection, and environmental and food safety identification.

SEISMIC VULNERABILITY ASSESSMENT FOR BUILDINGS OF PORT BLAIR CITY USING RAPID VISUAL SCREENING AS A TOOL

Andaman and Nicobar Islands is one of the most earthquake experienced areas around the world subjected to frequent earthquakes which is being the area of study using rapid visual screening (RVS) method by google maps and field visit as well. Although the google maps and internet sources can be used to cover up 80 percent data required for assessing and quantifying the RVS score but a field visit was made for extracting more relevant data for a detailed study. Port Blair municipal area was narrowed down for the screening since it had the greatest number of buildings. It was found that the moment resisting frames have been used in most of the buildings. RC moment resisting frames, load bearing structures, steel structures and wooden structures were studied in the screening and score was awarded. Gleaned from the score it was derived that old buildings are more susceptible for higher damage in near future then the recently constructed building.

Determination of Anti-Thrombin Active Components in Polygonum Amplexicaule Radix by Affinity-Ultrafiltration (AUF) and High-Performance – Tandem Mass Spectrometry (HPLC-MS/MS)

Polygonum Amplexicaule Radix is a traditional Chinese medicine for promoting blood circulation and removing blood stasis, which is often used to treat thrombotic diseases. However, its potential anticoagulant active ingredients have been unexplored. In this study, a method for rapid screening of anticoagulant active ingredients from P. amplexicaule by affinity-ultrafiltration (AUF) and high-performance – tandem mass spectrometry (HPLC-MS/MS) was established, which using thrombin as an affinity receptor target. 5 potential anti-thrombin active components were screened: gallic acid, procyanidin B2-3''O-gallate, 11-O-galloylbergenin, (-)-epicatechin gallate and di-galloyl-O-bergenin by AUF and HPLC-MS/MS. The inhibitory ability of these active ingredients to thrombin was confirmed by in vitro activity experiments and molecular docking, hence justifying that P. amplexicaule is a traditional Chinese medicine with excellent anticoagulation effects. Meanwhile, it has been shown that AUF-MS could be a way rapid screening for active substances.

Rapid screening and risk assessment of various elements in ultrafine granular powder of Panax quinquefolius L.

IntroductionPanax quinquefolius L. is obtained from a man-shaped root of several species of the genus Panax of the family Araliceae indigenous, which is thought to increase memory, decrease aging, and possess both digestion regulating and liver-protective activity. The widely used in daily life, making its risk assessment a matter of great importance. This research investigates the application of inductively coupled plasma mass spectrometry (ICP-MS) for rapid, non-targeted screening and risk assessment of various heavy metals and toxic agents in Panax quinquefolius L.'s ultrafine granular powder. MethodsThe Panax quinquefolius L. was ground to ultrafine granular powder and subjected to microwave digestion for pre-treatment. ICP-MS was then employed to scan all elements within the full spectrum range, allowing identification of heavy metals and toxic elements using the non-targeted detection method. Subsequently, risk assessment was conducted for Pb, Cu, Ni, Mn, Al, Hg, As, and Cd present in the powder, following the basic steps of risk assessment. ResultsThe concentrations of Pb, Cd, As, Hg, and Cu in ultrafine granular Panax quinquefolius L. powder were found to be below the limits established by the current pharmacopeia. Notably, essential trace elements for the human body, namely Ca, Fe, Mn, Zn, and Mg, were relatively abundant in the powder, with concentrations ranging from 1441.30 to 4016.20, 51.16 to 577.04, 34.78 to 121.99, 17.85 to 83.49, and 1017.69 to 3194.16 mg/kg, respectively. The risk assessment indicated that, in terms of exposure to toxic elements, the order for a person consuming ultrafine granular Panax quinquefolius L. powder would be: Al > Mn > Cu > Ni > Pb > Cd > As > Hg. Importantly, the non-cancer risks associated with Ni, Pb, Al, Mn, Cd, As, Hg, and Cu in the ultrafine granular Panax quinquefolius L. powder were all within acceptable levels. ConclusionThis study successfully establishes a multi-element non-targeted rapid screening method combined with risk assessment techniques, enabling swift determination of harmful target element concentrations and risk profiles in ultrafine granular Panax quinquefolius L. powder. This approach serves as a technical reserve for effectively responding to incidents of toxicity potentially associated with traditional Chinese medicine.

Development and Analytical Evaluation of a Point-of-Care Electrochemical Biosensor for Rapid and Accurate SARS-CoV-2 Detection.

The COVID-19 pandemic has underscored the critical need for rapid and accurate screening and diagnostic methods for potential respiratory viruses. Existing COVID-19 diagnostic approaches face limitations either in terms of turnaround time or accuracy. In this study, we present an electrochemical biosensor that offers nearly instantaneous and precise SARS-CoV-2 detection, suitable for point-of-care and environmental monitoring applications. The biosensor employs a stapled hACE-2 N-terminal alpha helix peptide to functionalize an in situ grown polypyrrole conductive polymer on a nitrocellulose membrane backbone through a chemical process. We assessed the biosensor's analytical performance using heat-inactivated omicron and delta variants of the SARS-CoV-2 virus in artificial saliva (AS) and nasal swab (NS) samples diluted in a strong ionic solution, as well as clinical specimens with known Ct values. Virus identification was achieved through electrochemical impedance spectroscopy (EIS) and frequency analyses. The assay demonstrated a limit of detection (LoD) of 40 TCID50/mL, with 95% sensitivity and 100% specificity. Notably, the biosensor exhibited no cross-reactivity when tested against the influenza virus. The entire testing process using the biosensor takes less than a minute. In summary, our biosensor exhibits promising potential in the battle against pandemic respiratory viruses, offering a platform for the development of rapid, compact, portable, and point-of-care devices capable of multiplexing various viruses. The biosensor has the capacity to significantly bolster our readiness and response to future viral outbreaks.

Bridged bicyclic compounds: Comprehending a novel compound class as potential anti-seizure agents.

In the present study, we describe a novel class of small-molecule synthetic compounds that ameliorate seizure-like behavior, using an electroshock assay to examine seizure duration in Caenorhabditis elegans. We also examine the hypothesis that these compounds, which we have called resveramorphs (RVMs), act by an irreversible binding mechanism. Our electroshock assay examines seizure duration in C. elegans and can be used as a drug-screening platform for the identification of novel anti-seizure agents. The use of C. elegans allows for a rapid and efficient method of drug screening that may take years in other higher-order model organisms. A novel wash method, paired with our electroshock assay, allows us to discern differences in biological activity when the C. elegans are incubated in different drug solutions, to establish whether these compounds can be "washed" off. One of the RVMs (RVM-3), reported here for the first time, was found to be potent at picomolar concentrations. Insights also provided information on the potential mechanisms of action of this compound. Covalent binding is thought to provide a strong irreversible bond because of a change in structure between two of the novel RVMs described in this work. This was also discerned through the novel wash method paired with our electroshock assay. RVM-3 was evaluated using our assay and found to possess anti-seizure activity at picomolar concentrations. These insights also provide information on the potential mechanisms of action of these compounds, which may include covalent binding. This was also discerned through a novel wash method paired with our electroshock assay.

National prevalence and risk factors for tungiasis in Kenya

BackgroundTungiasis is a highly neglected tropical skin disease caused by the sand flea, Tunga penetrans, the female of which burrows into the skin, causing pain and itching. The disease occurs throughout South America and sub-Saharan Africa but there are few systematic data on national disease burdens. The tungiasis research community is keen to develop survey methods to fill this gap. Here we used a school-based, thorough examination method to determine the prevalence and risk factors for tungiasis in Kenya.MethodsWe conducted the first nationally representative survey of tungiasis, including nine counties covering the major ecological zones of Kenya. A stratified multistage random sampling was used to select 22 primary schools from each of the nine counties and to select up to 114 pupils aged 8 to 14 years in each school. Pupils were examined thoroughly for tungiasis. Two surveys were conducted, the first between May and July 2021 and the second between October 2021 and April 2023 when pupils were also interviewed for risk factors. Mixed effect logistic regression models were used to test associations of independent variables with tungiasis using the school as a random effect.ResultsThe overall prevalence of tungiasis in the first survey was 1.35% [95% confidence interval (CI): 1.15–1.59%], and 0.89% in the second survey. The prevalence ranged from 0.08% (95% CI: 0.01–0.59%) in Taita Taveta county to 3.24% (95% CI: 2.35–4.44%) in Kajiado county. Tungiasis infection was associated with county of residence, male sex [adjusted odds ratio (aOR) = 2.01, 95% CI: 1.52–2.67], and lower age (aOR = 0.81, 95% CI: 0.75–0.88). For the first time we demonstrate an association with attending public schools rather than private schools (aOR = 5.62, 95% CI: 1.20–26.22) and lower socioeconomic status (aOR = 0.10, 95% CI: 0.03–0.33). Using a rapid screening method of the top of feet only, would have missed 62.9% of all cases, 78.9% of mild cases and 20.0% of severe cases.ConclusionsTungiasis is widely but heterogeneously distributed across Kenya. School-based surveys offer an efficient strategy for mapping tungiasis distribution.Graphical

Synergistic/antagonistic toxicity characterization and source-apportionment of heavy metals and organophosphorus pesticides by the biospectroscopy-bioreporter-coupling approach

Many anthropogenic chemicals are manufactured and eventually enter the surrounding environment, threatening food security and human health. Considering the additive or synergistic effects of pollutant mixtures, there is an expanding need for rapid, cost-effective and field-portable screening methods in environmental monitoring. This study used a recently developed biospectroscopy-bioreporter-coupling (BBC) approach to investigate the binary toxicity of Ag(I), Cr(VI) and four organophosphorus pesticides (dichlorvos, parathion, omethoate and monocrotophos). Ag(I) and Cr(VI) altered the toxicity mechanisms of pesticides, explained by the synergistic or antagonistic effect of Ag/Cr-induced cytotoxicity and pesticide-induced genotoxicity. The discriminating Raman spectral peaks associated with organophosphorus pesticides were 1585 and 1682 cm−1, but 750, 1004, 1306 and 1131 cm−1 were found in heavy metal and pesticide mixtures. More spectral alterations were related to pesticides rather than Ag(I) or Cr(VI), hinting at the dominant toxicity mechanisms of pesticides in mixtures. Ag(I) supplement significantly increased the levels of reactive oxygen species induced by organophosphorus pesticides, attributing to the increased permeability of cell membrane and entrance of toxic substances into the cells by the oligodynamic actions. This study lends deeper insights into the interactions between microbes and pollutant mixtures, offering clues to assess the cocktail effects of multiple pollutants comprehensively.

Characterization and designing of an SAM riboswitch to establish a high-throughput screening platform for SAM overproduction in Saccharomyces cerevisiae.

S-adenosyl- l-methionine (SAM)is a high-value compound widely used in the treatment of various diseases. SAM can be produced through fermentation, but further enhancing the microbial production of SAM requires novel high-throughput screening methods for rapid detection and screening of mutant libraries. In this work, anSAM-OFF riboswitch capable of responding to the SAM concentration was obtained and a high-throughput platform for screening SAM overproducers was established. SAM synthase was engineered by semirational design and directed evolution, which resulted in the SAM2S203F,W164R,T251S,Y285F,S365R mutant with almost twice higher catalytic activity than the parental enzyme. The best mutant was then introduced into Saccharomyces cerevisiae BY4741, and the resulting strain BSM8 produced a sevenfold higher SAM titer in shake-flask fermentation, reaching 1.25 g L-1 . This work provides a reference for designing biosensors to dynamically detect metabolite concentrations for high-throughput screening and the construction of effective microbial cell factories.