Ultrasensitive detection of SARS-CoV-2 S protein with aptamers biosensor based on surface-enhanced Raman scattering.

A rapid and accurate diagnostic modality is essential to prevent the spread of SARS-CoV-2. In this study, we proposed a SARS-CoV-2 detection sensor based on surface-enhanced Raman scattering (SERS) to achieve rapid and ultrasensitive detection. The sensor utilized spike protein deoxyribonucleic acid aptamers with strong affinity as the recognition entity to achieve high specificity. The spherical cocktail aptamers-gold nanoparticles (SCAP) SERS substrate was used as the base and Au nanoparticles modified with the Raman reporter molecule that resonates with the excitation light and spike protein aptamers were used as the SERS nanoprobe. The SCAP substrate and SERS nanoprobes were used to target and capture the SARS-CoV-2 S protein to form a sandwich structure on the Au film substrate, which can generate ultra-strong "hot spots" to achieve ultrasensitive detection. Analysis of SARS-CoV-2 S protein was performed by monitoring changes in SERS peak intensity on a SCAP SERS substrate-based detection platform. This assay detects S protein with a LOD of less than 0.7 fg mL-1 and pseudovirus as low as 0.8 TU mL-1 in about 12 min. The results of the simulated oropharyngeal swab system in this study indicated the possibility of it being used for clinical detection, providing a potential option for rapid and accurate diagnosis and more effective control of SARS-CoV-2 transmission.

Rapid Point-of-Care Assay by SERS Detection of SARS-CoV-2 Virus and Its Variants.

Addressing the spread of coronavirus disease 2019 (COVID-19) has highlighted the need for rapid, accurate, and low-cost diagnostic methods that detect specific antigens for SARS-CoV-2 infection. Tests for COVID-19 are based on reverse transcription PCR (RT-PCR), which requires laboratory services and is time-consuming. Here, by targeting the SARS-CoV-2 spike protein, we present a point-of-care SERS detection platform that specifically detects SARS-CoV-2 antigen in one step by captureing substrates and detection probes based on aptamer-specific recognition. Using the pseudovirus, without any pretreatment, the SARS-CoV-2 virus and its variants were detected by a handheld Raman spectrometer within 5 min. The limit of detection (LoD) for the pseudovirus was 124 TU µL-1 (18 fM spike protein), with a linear range of 250-10,000 TU µL-1. Moreover, this assay can specifically recognize the SARS-CoV-2 antigen without cross reacting with specific antigens of other coronaviruses or influenza A. Therefore, the platform has great potential for application in rapid point-of-care diagnostic assays for SARS-CoV-2.

Characterization of microbiome and metabolite analyses in patients with metabolic associated fatty liver disease and type II diabetes mellitus.

BACKGROUND: State-of-the-art renewal has indicated the improvement of diagnostics of patients with metabolic associated fatty liver disease (MAFLD) and/or type II diabetes mellitus (T2DM) by dissecting the clinical characteristics as well as genomic analysis. However, the deficiency of the characterization of microbial and metabolite signatures largely impedes the symptomatic treatment. METHODS: For the purpose, we retrospectively analyzed the clinical data of 20 patients with MAFLD (short for "M"), 20 cases with MAFLD and T2DM (short for "MD"), together with 19 healthy donors (short for "Ctr"). Microbial and metabolite analyses were further conducted to explore the similarities and differences among the aforementioned populations based on feces and blood samples, respectively. RESULTS: Compared with those in the Ctr group, patients with M or MD revealed multifaceted similarities (e.g., Age, ALP, LDL, BUN) and distinctions in clinical indicators of liver (e.g., BMI, ALT, PCHE, CAP). With the aid of microbial and metabolite analyses as well as bioinformatic analyses, we found that the characteristics of gut microbiota (e.g., abundance, hierarchical clustering, cladogram, species) and lipid metabolism (e.g., metabolite, correlation coefficient and scatter plot) were distinct among the indicated groups. CONCLUSIONS: The patients with MD revealed multifaceted similarities and distinctions in characteristics of microbiome and metabolites with those in the M and HD groups, and in particular, the significantly expressed microbes (e.g., Elusimicrobiota, Berkelbacteria, Cyanobacteria, Peregrinibacteria) and lipid metabolites (e.g., Lipid-Q-P-0765, Lipid-Q-P-0216, Lipid-Q-P-0034, Lipid-Q-P-0800), which would collectively benefit the clinical diagnosis of MAFLD and T2DM.

Arbitrary superposition of plasmonic orbital angular momentum states with nanostructures.

A kind of plasmonic nanostructure is proposed that can generate the arbitrary superposition of orbital angular momentum (OAM) states in surface plasmons (SPs), which is achieved by combining the segmented spirals with nanoslit pairs. The structures can independently modulate both the phase and amplitude of SP waves, and thus enable the superposition of two OAM states with arbitrary topological charges (TCs) as well as free control of their relative amplitudes. Superposed states distributed over the entire Bloch sphere and hybrid superposed states with different TCs were constructed and experimentally demonstrated. This work will offer more opportunities for multifunctional plasmonic devices.

Catalytic divergent synthesis of imidazoles via reaction condition-dependent [3 + 2] cyclization of TosMIC.

A base-catalyzed divergent synthesis of multisubstituted imidazoles through TosMIC-based [3 + 2] cyclization reaction has been developed. In the presence of ketenimines and tBuONa, 1,4,5-trisubstituted imidazoles were obtained. Nonetheless, in the absence of ketenimines, 1,4-disubstituted imidazole was produced through cyclodimerization of TosMIC.

The prevalence of liver abnormalities in humans due to Schistosoma japonicum by ultrasonography in China: a meta-analysis.

BACKGROUND: Schistosoma japonicum was once one of the most severe parasitic diseases in China. After 70 years of national schistosomiasis control programmes, the prevalence and associated morbidity of the infection have been reduced to a much lower level. However, due to the low sensitivity of the current detection approaches, many minor infections in humans could not be identified and ultimately develop chronic injuries with liver abnormalities, a specific 'network' echogenic pattern under ultrasonography. Therefore, as more people take part in physical examinations, we performed this meta-analysis to estimate the overall prevalence of schistosomiasis-associated liver abnormalities in China. METHODS: The publications were searched systematically across five electronic databases. All eligible studies were assessed with quality evaluation forms. Heterogeneity of studies was determined using the I2 and Q tests. A random effects or fixed effects model was employed based on heterogeneity results. The pooled prevalence and its 95% confidence intervals were calculated with the Freeman-Tukey double arcsine transformation. All analyses were conducted using R with the "meta" package. The protocol registration number was CRD42021232982. RESULTS: A total of 19 relevant articles, including 21 studies, were included. The average score of study quality was 6.4 (total score 7), indicating high quality of all included studies. A total of 268, 247 persons were included, and 43, 917 persons were diagnosed with schistosomiasis liver abnormalities by ultrasonography. High degrees of heterogeneity existed among all studies or within subgroups. The overall pooled prevalence was 18.64% (95% CI: 11.88-26.50%). The estimate significantly increased over time and varied among provinces, with the highest in Shanghai and the lowest in Sichuan. The estimate in people aged 60 years or older was significantly higher than that in people of all ages. No significant difference was seen when based on study areas (urban or rural areas) or gender. CONCLUSION: The long-term burden of schistosomiasis in China remains large, as nearly one-fifth of the examined persons were diagnosed with schistosomiasis liver abnormalities. The pooled prevalence was associated with regions or age groups. Such may have a high reference value in the exact calculation of the disease burden and can be helpful for policy makers in prioritizing public health.

Genetic diversity and structure of Oncomelania hupensis hupensis in two eco-epidemiological settings as revealed by the mitochondrial COX1 gene sequences.

BACKGROUND: Oncomelania hupensis hupensis is the only intermediate host of Schistosoma japonicum, the causative agent of schistosomiasis in China and is therefore of significant medical and veterinary health importance. Although tremendous progress has been achieved, there remains an understudied area of approximately 2.06 billion m2 of potential snail habitats. This area could be further increased by annual flooding. Therefore, an understanding of population genetics of snails in these areas may be useful for future monitoring and control activities. METHODS AND RESULTS: We sampled snails from Hexian (HX), Zongyang (ZY) and Shitai (ST) in Anhui (schistosomiasis transmission control), and from Hengtang (HT), Taicang (TC), Dongsan (DS) and Xisan (XS) in Jiangsu (schistosomiasis transmission interrupted), downstream of Anhui. ST, DS and XS are classified as hilly and mountainous areas, and HX, ZY, TC and HT as lake and marshland areas. The mitochondrial cytochrome c oxidase subunit I gene were sequenced. Out of 115 snails analyzed, 29 haplotypes were identified. We observed 56 (8.72%) polymorphic sites consisting of 51 transitions, four transversions and one multiple mutational change. The overall haplotype and nucleotide diversity were 0.899 and 0.01569, respectively. Snail populations in Anhui had higher genetic diversity than in Jiangsu. 73.32% of total variation was distributed among sites and 26.68% within sites. Snails were significantly separated according to eco-epidemiological settings in both network and phylogenetic analyses. CONCLUSION: Our results could provide important guidance towards assessing coevolutionary interactions of snails with S. japonicum, as well as for future molluscan host monitoring and control activities.

Generation of vector beams of Bell-like states by manipulating vector vortex modes with plasmonic metasurfaces.

Metasurfaces with orthogonal nano-slit pairs arranged on spirals are proposed to generate vector beams (VBs) of Bell-like states and slanted polarizations. The design of the metasurfaces is based on the theoretically derived parameter condition for manipulation of the two vector vortex modes, which is satisfied by matching the three parameters of rotation order m, the spiral order n, and incident polarization helicity σ. The linear polarization states of the VBs are controlled by the initial orientation angle φ0 of slit pairs. VBs of satisfying quality are experimentally obtained, with the analytical and simulated results validated.

An optical detection module-based biosensor using fortified bacterial beads for soil toxicity assessment.

An optical biosensor module for soil contamination assessment is presented, employing bioluminescent bacterial bioreporters encapsulated in poly-dopamine (PD)-coated alginate microbeads. The PD-coated beads displayed improved mechanical strength and stability, but somewhat delayed responses to the inducing toxicant. Using toluene as a model soil contaminant, two bioluminescent reporter strains were employed for its detection in the ambient light-blocking, temperature-controlled biosensor module. Bioluminescence of strain TV1061 (harboring an inducible grpE::luxCDABE fusion) increased and that of strain GC2 (harboring a constitutive lac::luxCDABE fusion) decreased in the presence of increasing toluene concentrations. In the former case, a maximal effect was observed in the presence of 1% toluene. This simple optical detection biosensor module may potentially be utilized for monitoring soil contamination from areas suspected of chemical pollution such petrochemical industrial zones or petrol stations.

Quantitative analysis of pH value in soil using laser-induced breakdown spectroscopy coupled with a multivariate regression method.

The quantitative analyses of pH value in soil have been performed using laser-induced breakdown spectroscopy (LIBS) technology. The aim of this work was to obtain a reliable and accurate method for rapid detection of pH value in soil. Seventy-four samples were used as a calibration set, and 24 samples were used as a prediction set. To eliminate the matrix effect, the multivariate models of partial least-squares regression (PLSR) and least-squares support vector regression (LS-SVR) were used to construct the models. The intensities of nine emission lines of C, Ca, Na, O, H, Mg, Al, and Fe elements were used to fit the models. For the PLSR model, the correlation coefficient was 0.897 and 0.906 for the calibration and prediction set, respectively. Furthermore, the analysis accuracy was improved effectively by the LS-SVR method, and the correlation coefficients for calibration and prediction set were improved to 0.991 and 0.987. The prediction mean absolute error was pH 0.1 units, and the root mean square error of the prediction was only 0.079. The results indicated that the LIBS technique coupled with LS-SVR could be a reliable and accurate method for determining pH value in soil.

[Interpreting the Methods for Blending Decoctions to Treat 60 Ailments in Tianhui bamboo slip medical manuscripts].

Among the medical texts excavated in 2012-2013 from the Han Dynasty tomb at Tianhui township in Sichuan province, we found a collection on the treatment of 60 ailments. Under each ailment, we found one or more formulas, for a total of 106 formulas. The authors of this paper compiled and analyzed these texts based on the original bamboo slips and named this collection with the title Methods for Blending Decoctions to Treat 60 Ailments because the content was focused on blending and making medicinal formulas, and also due to the historical connections with the texts the Record of the Court Scribe, "Biography of Bian Que and Cang Gong". For these reasons, this title was determined, where "blending decoctions" mean "blending and harmonizing medicines optimally in preparation for decocting". The Tianhui texts preserve ancient forms of medicinal formulas, including some once believed to be lost, such as "grain decoctions", "fermented alcohol decoctions", and "fiery decoctions". Based on the historical evidence, we can now ascertain that this text is the "Blending Formulas and Making Decoctions" mentioned in the Record of the Court Scribe written by Cang Gong. Moreover, the medical texts, Canon Formulas in Decoction Form (from the book of Han Dynasty) and the Imperial Pharmacy Formulas to Benefit the People in Song Dynasty are both of this genre of medical literature. The Tianhui text is therefore a representative of this genre of literature in the Western and eastern Han, acting as a key link between early medical formula books and later formula books.

A novel reflectance-based aptasensor using gold nanoparticles for the detection of oxytetracycline.

We present a novel reflectance-based colorimetric aptasensor using gold nanoparticles for the detection of oxytetracycline for the first time. It was found that the reflectance-based measurement at two wavelengths (650 and 520 nm) can generate more stable and sensitive signals than absorbance-based sensors to determine the aggregation of AuNPs, even at high AuNP concentrations. One of the most common antibacterial agents, oxytetracycline (OTC), was detected at concentrations as low as 1 nM in both buffer solution and tap water, which was 25-fold more sensitive, compared to the previous absorbance-based colorimetric aptasensors. This reflectance-based colorimetric aptasensor using gold nanoparticles is considered to be a better platform for portable sensing of small molecules using aptamers.

[Chemical Constituents from Rhizome of Valeriana jatamansi].

OBJECTIVE: To study the chemical constituents from the rhizome of Valeriana jatamansi. METHODS: The chemical constituents were separated and purified by silica gel, medium pressure column chromatography, and preparative HPLC. Their structures were determined by physicochemical properties and spectral data. RESULTS: Six compounds were isolated from the dibromochloromethane extract in the rhizome of Valeriana jatamansi, and identified as decursidin (1), decursitin B (2), decursitin A (3), 3'(S)-acetoxy-4'(R)-angeloyloxy-3',4'-dihydroxanthyletin (4), 8-acetoxyl-pathchouli alcohol (5) and dibutyl phthalate (6). CONCLUSION: Compounds 1-4 are coumarins which are isolated from this genus for the first time,and compound 6 is isolated from this genus for the first time.

A dip-stick type biosensor using bioluminescent bacteria encapsulated in color-coded alginate microbeads for detection of water toxicity.

The use of genetically engineered bioluminescent bacteria, in which bioluminescence is induced by different modes of toxic action, represents an alternative to acute toxicity tests using living aquatic organisms (plants, vertebrates, or invertebrates) in an aqueous environment. A number of these bacterial strains have been developed, but there have been no attempts to develop a hand-held type of biosensor for monitoring or identification of toxicity. We report a facile dip-stick type biosensor using genetically engineered bioluminescent bacteria as a new platform for classification and identification of toxicity in water environments. This dip-stick type biosensor is composed of eight different optically color-coded functional alginate beads that each encapsulates a different bioluminescent bacterial strain and its corresponding fluorescent microbead. These color-coded microbeads exhibit easy identification of encapsulated microbeads, since each microbead has a different color code depending on the bioluminescent bacterial strain contained and improved cell-stability compared to liquid culture. This dip-stick type biosensor can discriminate different modes of toxic actions (i.e. DNA damage, oxidative damage, cell-membrane damage, or protein damage) of sample water tested by simply dipping the stick into the water samples. It was found that each color-coded microbead emitted distinct bioluminescence, and each dip-stick type biosensor showed different bioluminescence patterns within 2 hours, depending on the toxic chemicals contained in LB medium, tap water, or river water samples. This dip-stick type biosensor can, therefore, be widely and practically used in checking toxicity of water in the environment primarily in situ, possibly indicating the status of biodiversity.

Group selective aptamers: Broad-spectrum recognition of target groups in Cronobacter species and implementation of electrochemical biosensors as receptors.

Aptamers are a versatile class of receptors with a high affinity and selectivity for specific targets. Although their ability to recognize individual targets has been extensively studied, some scenarios require the development of receptors capable of identifying all target groups. This study investigated the use of aptamers to achieve the broad-spectrum recognition of groups instead of individual targets. Aptamers were screened for selectively distinct groups of Cronobacter species associated with foodborne diseases. Seven Cronobacter spp. were divided into Group A (C. sakazakii, C. malonaticus, C. turicensis, and C. muytjensii) and Group B (C. dublinensis, C. condimenti, and C. universalis). Aptamers with exclusive selectivity for each group were identified, allowing binding to the species within their designated group while excluding those from the other group. The screened aptamers demonstrated reliable affinity and specificity with dissociation constants ranging from 1.3 to 399.7 nM for Group A and 4.0-24.5 nM for Group B. These aptamers have also been successfully employed as receptors in an electrochemical biosensor platform, enabling the selective detection of each group based on the corresponding aptamer (limit of detection was 7.8 and 3.2 CFU for Group A and Group B, respectively). The electrochemical sensor effectively detected the extent of infection in each group in powdered infant formula samples. This study highlights the successful screening and application of group-selective aptamers as sensing receptors, emphasizing their potential for diverse applications in different fields such as food safety, environmental monitoring, and clinical diagnostics, where the selective biosensing of target groups is crucial.

An IoT-based aptasensor biochip for the diagnosis of periodontal disease.

Severe periodontitis affects nearly 1 billion individuals worldwide, highlighting the need for early diagnosis. Here, an integrated system consisting of a microfluidic chip and a portable point-of-care (POC) diagnostic device is developed using a polymethyl methacrylate (PMMA) chip fabrication and a three-dimensional printing technique, which is automatically controlled by a custom-designed smartphone application to routinely assess the presence of a specific periodontitis biomarker, odontogenic ameloblast-associated protein (ODAM). A sandwich-type fluorescence aptasensor is developed on a microfluidic chip, utilizing aptamer pair (MB@OD64 and OD35@FAM) selectively binding to target ODAM. Then this microfluidic chip is integrated into an automated Internet of Things (IoT)-based POC device, where fluorescence intensity, as a signal, from the secondary aptamer binding to ODAM in a sandwich-type binding reaction on the microfluidic chip is measured by a complementary metal oxide semiconductor (CMOS) camera with a 488 nm light-emitting diode (LED) excitation source. Obtained signals are processed by a microprocessor and visualized on a wirelessly connected smartphone application. This integrated biosensor system allows the rapid and accurate detection of ODAM within 30 min with a remarkable limit of detection (LOD) of 0.011 nM under buffer conditions. Clinical application is demonstrated by successfully distinguishing between low-risk and high-risk individuals with 100 % specificity. A strong potential in the translation of this fluorescence-based microfluidic aptasensor integrated with an IoT-based POC system is expected to be employed for non-invasive, on-site, rapid, and accurate ODAM detection, facilitating periodontitis diagnosis.

Depletion of proteasome subunit PSMD1 induces cancer cell death via protein ubiquitination and DNA damage, irrespective of p53 status.

Hepatocellular carcinoma (HCC) is characterized by high incidence and fatality rates worldwide. In our exploration of prognostic factors in HCC, the 26s proteasome subunit, non-ATPase 1 (PSMD1) protein emerged as a significant contributor, demonstrating its potential as a therapeutic target in this aggressive cancer. PSMD1 is a subunit of the 19S regulatory particle in the 26S proteasome complex; the 19S particle controls the deubiquitination of ubiquitinated proteins, which are then degraded by the proteolytic activity of the complex. Proteasome-targeting in cancer therapy has received significant attention because of its practical application as an established anticancer agent. We investigated whether PSMD1 plays a critical role in cancer owing to its prognostic significance. PSMD1 depletion induced cell cycle arrest in G2/M phase, DNA damage and apoptosis of cancer cells, irrespective of the p53 status. PSMD1 depletion-mediated cell death was accompanied by an increase in overall protein ubiquitination. These phenotypes occurred exclusively in cancer cells, with no effects observed in normal cells. These findings indicate that PSMD1 depletion-mediated ubiquitination of cellular proteins induces cell cycle arrest and eventual death in cancer cells, emphasizing PSMD1 as a potential therapeutic target in HCC.

Detection of VR-2332 strain of porcine reproductive and respiratory syndrome virus type II using an aptamer-based sandwich-type assay.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes porcine reproductive and respiratory syndrome disease (PRRS), a disease that has a significant and economic impact on the swine industry. In this study, single-stranded DNA (ssDNA) aptamers with high specificity and affinity against VR-2332 strain of PRRSV type II were successfully obtained. Of 19 candidates, the LB32 aptamer was found to be the most specific and sensitive to VR-2332 strain according to an aptamer-based surface plasmon resonance (SPR) analysis. The detection of VR-2332 of PRRSV type II was successfully accomplished using the enzyme-linked antibody-aptamer sandwich (ELAAS) method. The detection limit of ELAAS was 4.8 × 10(0) TCID(50)/mL that is comparable to some of the previous reports of the PCR-based detection but does not require any complicated equipment or extra costs. Moreover, this ELAAS-based PRRSV detection showed similar sensitivity for both the VR-2332 samples spiked in diluted swine serum and in buffer. Therefore, this VR-2332 strain-specific aptamer and its assay method with high specificity can be used as an alternative method for the fast and precise detection of PRRSV.

Conversion of carbon dioxide to oxaloacetate using integrated carbonic anhydrase and phosphoenolpyruvate carboxylase.

The development and implementation of strategies for CO2 mitigation are necessary to counteract the greenhouse gas effect of carbon dioxide emissions. To demonstrate the possibility of simultaneously capturing CO2 and utilizing four-carbon compounds, an integrated system using CA and PEPCase was developed, which mimics an in vivo carbon dioxide concentration mechanism. We first cloned the PEPCase 1 gene of the marine diatom Phaeodactylum tricornutum and produced a recombinant PtPEPCase 1. The affinity column purified PtPEPCase 1 exhibited specific enzymatic activity (5.89 U/mg). When the simultaneous and coordinated reactions of CA from Dunaliella sp. and the PtPEPCase 1 occurred, more OAA was produced than when only PEPCase was present. Therefore, this integrated CA-PEPCase system can be used not only to capture CO2 but also for a new technology to produce value-added four-carbon platform chemicals.

[Optimization of ultrasonic extraction conditions of safflower yellow from Carthamus tinctorius by response surface methodology].

OBJECTIVE: To investigate the optimization of extraction conditions of safflower yellow from Cartbamus tirwtorius by response surface methodology. METHODS: Experimental factors and levels were selected by one-factor test, and then according to the central composite experimental design principle, response surface'-methodology with three factors and three levels was used to establish a mathematical model to obtain the optimal extraction conditions with hydroxysafflower yellow A being the target and its extraction yield as response value. RESULTS: The optimal extraction conditions of safflower yellow were as follows: extraction temperature was 55 t, ratio of water to raw material was 16:1 and extraction time was 39 mm for three times. CONCLUSION: Under these conditions, the extraction yield of safflower yellow is 1.798%, and the relative error between the predicted value with actual value is 2.758%. The optimized method can provide reference for the efficient extraction of safflower yellow from Carthomos tinctorius