Optical lateral flow assays in early diagnosis of SARS-CoV-2 infection.

So far, the 2019 novel coronavirus (COVID-19) is spreading widely worldwide. The early diagnosis of infection by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is essential to provide timely treatment and prevent its further spread. Lateral flow assays (LFAs) have the advantages of rapid detection, simple operation, low cost, ease of mass production, and no need for special devices and professional operators, which make them suitable for self-testing at home. This review focuses on the early diagnosis of SARS-CoV-2 infection based on optical LFAs including colorimetric, fluorescent (FL), chemiluminescent (CL), and surface-enhanced Raman scattering (SERS) LFAs for the detection of SARS-CoV-2 antigens and nucleic acids. The types of recognition components, detection modes used for antigen detection, labels employed in different optical LFAs, and strategies to improve the detection sensitivity of LFAs were reviewed. Meanwhile, LFAs coupled with different nucleic acid amplification techniques and CRISPR-Cas systems for the detection of SARS-CoV-2 nucleic acids were summarized. We hope this review provides research mentalities for developing highly sensitive LFAs that can be used in home self-testing for the early diagnosis of SARS-CoV-2 infection.

Prolonged fasting induces significant germ cell loss in chickens after hatching.

Germ cell loss is a crucial biological event during germ cell development. The number of female germ cells determines the reproductive performance and egg production of hens. Various intrinsic and extrinsic factors affect germ cell loss, such as germ cell nest breakdown in early life and nutritional deficiencies during daily husbandry. Here, we examined the effect of fasting on the germ cell number of chicks. The results showed that 72 h fasting resulted in a higher germ cell loss than that by 24 h fasting in chicks. The RNA-seq analysis revealed that the genes of ribosome pathway were down-regulated and the biological processes of protein processing in endoplasmic reticulum were inhibited in starved chicks. Furthermore, in female chicks treated with 72 h fasting, the qPCR of ovaries showed down-regulation of ribosome-related genes, and transmission electron microscopy imaging of ovaries showed fewer ribosomes. The blood biochemical indices indicated that 72 h fasting reduced the liver functions and affected the glucose metabolism, lipid metabolites and ion metabolites. In summary, the present results concluded negative impacts on the germ cell pool by prolonged fasting in the early life of chicks and manifested that adequate management should be cared for fasted time for breeding.

Transcriptomic analysis reveals the formation mechanism of anemone-type flower in chrysanthemum.

BACKGROUND: The ray and disc florets on the chrysanthemum capitulum are morphologically diverse and have remarkably abundant variant types, resulting in a rich variety of flower types. An anemone shape with pigmented and elongated disk florets is an important trait in flower shape breeding of chrysanthemums. The regulatory mechanism of their anemone-type disc floret formation was not clear, thus limiting the directional breeding of chrysanthemum flower types. In this study, we used morphological observation, transcriptomic analysis, and gene expression to investigate the morphogenetic processes and regulatory mechanisms of anemone-type chrysanthemum. RESULT: Scanning electron microscopy (SEM) observation showed that morphological differences between non-anemone-type disc florets and anemone-type disc florets occurred mainly during the petal elongation period. The anemone-type disc florets elongated rapidly in the later stages of development. Longitudinal paraffin section analysis revealed that the anemone-type disc florets were formed by a great number of cells in the middle layer of the petals with vigorous division. We investigated the differentially expressed genes (DEGs) using ray and disc florets of two chrysanthemum cultivars, 082 and 068, for RNA-Seq and their expression patterns of non-anemone-type and anemone-type disc florets. The result suggested that the CYCLOIDEA2 (CYC2s), MADS-box genes, and phytohormone signal-related genes appeared significantly different in both types of disc florets and might have important effects on the formation of anemone-type disc florets. In addition, it is noteworthy that the auxin and jasmonate signaling pathways might play a vital role in developing anemone-type disc florets. CONCLUSIONS: Based on our findings, we propose a regulatory network for forming non-anemone-type and anemone-type disc florets. The results of this study lead the way to further clarify the mechanism of the anemone-type chrysanthemum formation and lay the foundation for the directive breeding of chrysanthemum petal types.

The osteoporosis risk variant rs9820407 at 3p22.1 acts as an allele-specific enhancer to regulate CTNNB1 expression by long-range chromatin loop formation.

Previous powerful genome-wide association studies (GWASs) and whole-genome sequencing have identified multiple single-nucleotide polymorphisms (SNPs) located over 69 kb upstream of CTNNB1 at 3p22.1 locus associated with osteoporosis. The CTNNB1 gene encodes ß-catenin that is an integral part of adherens junctions and the primary mediator of the canonical Wnt signaling pathway. The causal variants and underlying molecular mechanisms of the osteoporosis susceptibility locus 3p22.1 remains unknown. Through comprehensive computational analyses, including expression quantitative trait locus (eQTL), high-throughput chromatin interaction (Hi-C), epigenomic and functional annotation, four enhancer SNPs (rs9820407, rs9878224, rs454690 and rs9832204) were prioritized as potential causal SNPs at 3p22.1 for osteoporosis. Rs9820407 displayed the strongest enhancer activity in dual-luciferase assays. Specifically, the minor rs9820407-A can preferentially bind transcription factor FOXC1, elevate the enhancer activity and increase CTNNB1 expression. The architectural protein CTCF was presumably involved in long-range chromatin interaction between rs9820407 and CTNNB1. Our study provided a mechanistic insight into how noncoding enhancer SNP rs9820407 distally regulates CTNNB1 expression and modulates osteoporosis risk.

USF3 modulates osteoporosis risk by targeting WNT16, RANKL, RUNX2, and two GWAS lead SNPs rs2908007 and rs4531631.

Osteoporotic fractures cause major morbidity and mortality in the aging population. Genome-wide association studies (GWAS) have identified USF3 as the novel susceptibility gene of osteoporosis. However, the functional role in bone metabolism and the target gene of the basic helix-loop-helix transcription factor USF3 are unclear. Here, we show that USF3 enhances osteoblast differentiation and suppresses osteoclastogenesis in cultured human osteoblast-like U-2OS cells. Mechanistic studies revealed that transcription factor USF3 antagonistically interacts with anti-osteogenic TWIST1/TCF12 heterodimer in the WNT16 and RUNX2 promoter, and counteracts CREB1 and JUN/FOS in the RANKL promoter. Importantly, the osteoporosis GWAS variant g.1744A>G (rs2908007A>G) located in the WNT16 promoter confers G-allele-specific transcriptional modulation by USF3, TWIST1/TCF12 and TBX5/TBX15, and USF3 transactivates the osteoclastogenesis suppressor WNT16 promoter activity and antagonizes the repression of WNT16 by TWIST1 and TCF12. The risk G allele of osteoporosis GWAS variant g.3260A>G (rs4531631A>G) in the RANKL promoter facilitates the binding of CREB1 and JUN/FOS and enhances transactivation of the osteoclastogenesis contributor RANKL that is inhibited by USF3. Our findings uncovered the functional mechanisms of osteoporosis novel GWAS-associated gene USF3 and lead single nucleotide polymorphisms rs2908007 and rs4531631 in the regulation of bone formation and resorption.

Potential regulation of small RNAs on bacterial function activities in pig farm wastewater treatment plants.

Small RNAs (sRNAs) are key players in the regulation of bacterial gene expression. However, the distribution and regulatory functions of sRNA in pig farm wastewater treatment plants (WWTPs) remains unknown. In this study, the wastewaters in anoxic and oxic tanks of the WWTPs were collected. The profiles of the community structure, mRNA expression, and sRNA expression of bacteria in pig farm wastewater were investigated using transcriptome sequencing and qPCR. This study demonstrated that there was a higher abundance of sRNA in the pig farm WWTPs and 52 sRNAs were detected. The sRNAs were mainly present in Proteobacteria and Firmicutes, including the potential human pathogenic bacteria (HPB) (Escherichia, Shigella, Bordetella and Morganella), crop pathogen (Pectobacterium) and denitrifying bacteria (Zobellella). And the sRNAs were involved in the bacterial functional activities such as translation, transcription, drug resistance, membrane transport and amino acid metabolism. In addition, most sRNAs had a higher abundance in anoxic tanks which contained a higher abundance of the genes associated with infectious diseases and drug resistance than that in oxic tanks. The results presented here show that in pig farm WWTPs, sRNA played an important role in bacterial function activities, especially the infectious diseases, drug resistance and denitrification, which can provide a new point of penetration for improving the pig farm WWTPs.

LncRNA ZBTB40-IT1 modulated by osteoporosis GWAS risk SNPs suppresses osteogenesis.

Previous genome-wide linkage and association studies have identified an osteoporosis-associated locus at 1p36 that harbors SNPs rs34920465 and rs6426749. The 1p36 locus also comprises the WNT4 gene with known role in bone metabolism and functionally unknown ZBTB40/lncRNA ZBTB40-IT1 genes. How these might interact to contribute to osteoporosis susceptibility is not known. In this study, we show that lncRNA ZBTB40-IT1 is able to suppress osteogenesis and promote osteoclastogenesis by regulating the expression of WNT4, RUNX2, OSX, ALP, COL1A1, OPG and RANKL in U-2OS and hFOB1.19 cell lines, whereas ZBTB40 plays an opposite role in bone metabolism. Treatment with parathyroid hormone significantly downregulates the expression of ZBTB40-IT1 in U-2OS cell lines. ZBTB40 can suppress ZBTB40-IT1 expression but has no response to parathyroid hormone treatment. Dual-luciferase assay and biotin pull-down assay demonstrate that osteoporosis GWAS lead SNPs rs34920465-G and rs6426749-C alleles can respectively bind transcription factors JUN::FOS and CREB1, and upregulate ZBTB40 and ZBTB40-IT1 expression. Our study discovers the critical role of ZBTB40 and lncRNA ZBTB40-IT1 in bone metabolism, and provides a mechanistic basis for osteoporosis GWAS lead SNPs rs34920465 and rs6426749.

A dual-readout chemiluminescent-gold lateral flow test for multiplex and ultrasensitive detection of disease biomarkers in real samples.

Even though the gold lateral flow test (GLFT) is low-cost and allows for point-of-care testing (POCT), its intrinsic limitations including low sensitivity and incapability of quantification significantly hinder the clinical application of GLFT for assaying disease biomarkers. To improve the performance of the GLFT without sacrificing its simplicity, we develop a chemiluminescent-gold lateral flow test (C-mode GLFT) for quantitative and multiplex detection of disease biomarkers with an ultrahigh sensitivity at a picomolar level. Horseradish peroxidase (HRP) and antibody (Ab) are simultaneously labeled onto the surface of gold nanoparticles (AuNPs) to achieve a dual-readout (chemiluminescent and visual, C&V-mode GLFT). A red color appears at the test line caused by the accumulation of captured AuNPs in the presence of targets, while HRP on the surface of AuNPs catalyzes the chemiluminescence reaction of luminol to amplify the signal. C-mode GLFT is successfully used for detecting tumor biomarkers (alpha fetoprotein, AFP, and carcino embryonic antigen, CEA) and bacterial infection biomarkers (procalcitonin, PCT) in serum samples as well as whole blood. The excellent features of C-mode GLFT such as straightforward operation, ultrahigh sensitivity and quantitative detection, make it a promising platform for POCT of a variety of disease biomarkers in real samples.

One-step detection of pathogens and cancer biomarkers by the naked eye based on aggregation of immunomagnetic beads.

This report shows that immunomagnetic beads (IMBs) can act as the optical readout for assays, in addition to serving as the carrier for purification/separation. Under the influence of an external magnet, IMBs are attracted to coat one side of a test tube. IMBs specifically bound to targets can form a narrow brown stripe, whereas free IMBs will form a diffuse, yellow coating on the side of the test tube. Target analytes can aggregate initially dispersed IMBs in a sample concentration-dependent manner, yielding a color change from yellow to brown that can be seen with the naked eye. This assay combines the convenience of a lateral flow assay, allowing a one-step assay to finish within 15 min, with the sensitivity of an enzyme-linked immonosorbent assay.

Turn-on colorimetric sensor for ultrasensitive detection of thrombin using fibrinogen-gold nanoparticle conjugate.

A simple, colorimetric 'turn on' sensor for ultrasensitive detection of thrombin has been developed using fibrinogen-modified gold nanoparticles (Fib-Au NPs). The assay was based on the thrombin-fibrinogen interaction which is part of the physiological process of blood clotting. The fibrinogen was immobilized on the surface of 96-well plate offering reactive N-oxysuccinimide esters (referred to as NOS group) surface. Introducing thrombin and Fib-Au NPs into the fibrinogen-bound 96-well plate induced the immobilization of Fib-Au NPs on the surface of 96-well plate through the thrombin mediated conversion of soluble fibrinogen to insoluble cross-linked fibrin. Such process could be detected visually post HAuCl(4)-NH(2)OH redox reaction catalyzed by the Au NPs. The parameters governing the performance of the assay have been optimized. The detection limit was 3.2 fM, corresponding to 0.16 amol thrombin in 50 µL of sample. Other proteins, such as bovine serum albumin (BSA), pepsin, trypsin, hemoglobin, lysozyme, and cytochrome c did not show interference with the assay of thrombin. In addition, the work demonstrates the feasibility of thrombin detection in a complex matrix, showing potential for rapid medical diagnostics.

Transcriptome-wide survey and expression analysis of stress-responsive NAC genes in Chrysanthemum lavandulifolium.

The plant-specific NAC (NAM, ATAF, and CUC) transcription factor family plays a vital role in various plant growth and developmental processes as well as in stress resistance. Using RNA sequencing, we found that the ClNAC genes (ClNAC1-44) were the most strongly up-regulated transcription factor family in Chrysanthemum lavandulifolium leaves under salt treatment. We carried out reverse transcriptase polymerase chain reaction to monitor ClNAC genes response against multiple stresses and hormonal treatments including salt, drought, cold, heat, abscisic acid and salicylic acid treatments. The results showed that 35 ClNAC genes were differentially expressed in different organ, and 32 ClNAC genes could respond to at least 2 kinds of treatments. Quantitative real time polymerase chain reaction showed that 10 ClNAC genes belonging to 7 different subfamilies could respond to at least 5 kinds of treatments. Over 50-fold variation in transcriptional levels of ClNAC17 and ClNAC21 genes was observed under 6 different types of treatments. In the present study, high-level expression of ClNAC genes under abiotic stresses and hormonal treatments suggests that the NAC transcription factors play important roles in abiotic stress tolerance and adaptation.

Conformational switching immobilized hairpin DNA probes following subsequent expanding of gold nanoparticles enables visual detecting sequence-specific DNA.

A simple, rapid, and sensitive method for visual detection of sequence-specific DNA was developed using hairpin DNA as the recognition element and hydroxylamine-enlarged gold nanoparticles (Au-NPs) as the signal producing component. In the assay, we employed a hairpin DNA probe dually labeled with amine and biotin at the 5'- and 3'-end, respectively. The probe was coupled with reactive N-oxysuccinnimide in a DNA-bind 96-well plate. Without the target DNA, the immobilized hairpin probe was in a "closed" state, which kept the streptavidin-gold off the biotin. The hybridization between the loop sequence and the target broke the short stem duplex upon approaching the target DNA. Consequently, biotin was forced away from the 96-well plate surface and available for conjugation with the streptavidin-gold. The hybridization could be detected visually after the HAuCl(4)-NH(2)OH redox reaction catalyzed by the Au-NPs. Under the optimized conditions, the visual DNA sensor could detect as low as 100 amol of DNA targets with excellent differentiation ability and even a single-base mismatch.

Rhein, an inhibitor of adipocyte differentiation and adipogenesis.

Rhein (RH), a compound purified from Radix et Rhizoma Rhei, has been used to alleviate liver and kidney damage. It is found that RH inhibited the differentiation of 3T3-L1 preadipocytes induced by differentiation medium in a time- and dose-dependent manner. It was revealed that RH downregulated the expression of adipogenesis-specific transcription factors PPARγ and C/EBPα, as well as their upstream regulator, C/EBPß. Furthermore, the PPARγ target genes that are involved in adipocyte differentiation, such as CD36, aP2, acyl CoA oxidase, uncoupled protein 2, acetyl-CoA carboxylase, and fatty acid synthase, were reduced after to RH. In addition, high-fat diet-induced weight gain and adiposity were reversed by RH in C57BL/6 mice. Consistent with the cells' results, RH downregulated the mRNA levels of PPARγ and C/EBPα, and their downstream target genes in C57BL/6 mice. Taken together, adipocyte differentiation and adipogenesis were inhibited by RH in cultured cells and in rodent models of obesity. The evidence implied that RH was a potential candidate for preventing metabolic disorders.

Improvement on lipid metabolic disorder by 3'-deoxyadenosine in high-fat-diet-induced fatty mice.

This study explores the effects of 3'-deoxyadenosine, a compound from Cordyceps militaris, on lipid metabolic disorder induced by a high-fat-diet in C57BL/6 mice. These mice had an obese body, lipid metabolic disorder and insulin resistance and were treated orally with 100 mg/kg/day 3'-deoxyadenosine (DA), 15 mg/kg/day rosiglitazone and 150 mg/kg/day fenofibrate, respectively. Compared to the model mice, the body weight gain in DA-treated mice were decreased by 66.5%, serum triglyceride and total cholesterol levels were decreased by 20.7% and 16.7%, respectively, and the triglyceride content in the skeletal muscle was reduced by 41.2%. This treatment also had a significant effect on insulin resistance. In DA-treated mice, the serum insulin levels and homeostasis model assessment of the insulin resistance index were decreased by 30% and 46%, respectively, and the areas under the glucose-time curve were depressed by 18% in the insulin tolerance test and by 21.5% in the oral glucose tolerance test. Finally, the value of glucose infusion rates and insulin induced-glucose uptake into the skeletal muscle in the hyperinsulinemic-euglycemic clamp test were increased by 18% and 41%, respectively, compared to those in the model mice. This data suggests that the effects of DA on lipid metabolic disorder induced by a high-fat-diet may be linked to its improvement on insulin resistance, especially concerning the increase of insulin sensitivity in the skeletal muscle.