SARS-Cov-2 Spike-S1 Antigen Test Strip with High Sensitivity Endowed by High-Affinity Antibodies and Brightly Fluorescent QDs/Silica Nanospheres.

The extensive research into developing novel strategies for detecting respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in clinical specimens, especially the sensitive point-of-care testing method, is still urgently needed to reach rapid screening of viral infections. Herein, a new lateral flow immunoassay (LFIA) platform was reported for the detection of SARS-CoV-2 spike-S1 protein antigens, in which four sensitive and specific SARS-CoV-2 mouse monoclonal antibodies (MmAbs) were tailored by using quantum dot (QD)-loaded dendritic mesoporous silica nanoparticles modified further for achieving the -COOH group surface coating (named Q/S-COOH nanospheres). Importantly, compact QD adsorption was achieved in mesoporous channels of silica nanoparticles on account of highly accessible central-radial pores and electrostatic interactions, leading to significant signal amplification. As such, a limit of detection for SARS-CoV-2 spike-S1 testing was found to be 0.03 ng/mL, which is lower compared with those of AuNPs-LFIA (traditional colloidal gold nanoparticles, Au NPs) and enzyme-linked immunosorbent assay methods. These results show that optimizing the affinity of antibody and the intensity of fluorescent nanospheres simultaneously is of great significance to improve the sensitivity of LFIA.

AKG induces cell apoptosis by inducing reactive oxygen species-mediated endoplasmic reticulum stress and by suppressing PI3K/AKT/mTOR-mediated autophagy in renal cell carcinoma.

BACKGROUND: Alpha-ketoglutarate (AKG) or 2-oxoglutarate is a key substance in the tricarboxylic acid cycle (TCA) and has been known to play an important role in cancerogenesis and tumor progression. Renal cell carcinoma (RCC) is the most common type of kidney cancer, and it has a high mortality rate. Autophagy is a phenomenon of self-digestion, and its significance in tumor genesis and progression remains debatable. However, the mechanisms underlying how AKG regulates autophagy in RCC remain unknown. Thus, the purpose of this study was to assess the therapeutic efficacy of AKG and its molecular mechanisms. METHODS: RCC cell lines 786O and ACHN were treated with varying doses of AKG for 24 h. CCK-8, Transwell, and scratch wound healing assays were utilized to evaluate the role of AKG in RCC cells. Autophagy protein and PI3K/AKT/mTOR pathway protein levels were analyzed by Western blot. RESULTS: AKG inhibited the proliferation of RCC cells 786O and ACHN in a dose-dependent manner according to the CCK-8 assay. In addition, flow cytometry and Western blot analysis revealed that AKG dose-dependently triggered apoptosis and autophagy in RCC cells. By promoting cell apoptosis and autophagy, AKG dramatically suppressed tumor growth. Mechanistically, AKG induces autophagy by promoting ROS generation and inhibiting the PI3K/AKT/mTOR pathway. CONCLUSIONS: The anti-tumor effect of AKG promotes autophagy in renal cancer cells via mediating ROS-PI3K/Akt/mTOR, and may be used as a potential anticancer drug for kidney cancer.

Pyrocatechol Alleviates Cisplatin-Induced Acute Kidney Injury by Inhibiting ROS Production.

As one of the most common cancer chemotherapy drugs, cisplatin is widely used in cancer management. However, cisplatin-induced nephrotoxicity occurs in patients who receive this drug. This study is aimed at developing therapeutic agents that effectively alleviate the nephrotoxic effects during cisplatin treatment. We identified a compound named pyrocatechol (PCL) from a natural product library that significantly alleviated cisplatin-induced cytotoxicity in vitro. Pyrocatechol treatment substantially ameliorated cisplatin (20 mg · kg-1) treatment-induced neuropathological indexes, including inflammatory cell infiltration and apoptosis, in vivo. Mechanistically, pyrocatechol significantly prevented oxidative stress-induced apoptosis by activating glutathione peroxidase 4 (GPX4) to reduce reactive oxygen species (ROS) accumulation in cisplatin-treated cells. In addition, pyrocatechol significantly inhibited ROS-induced JNK/P38 activation. Thus, we found that pyrocatechol prevents ROS-mediated JNK/P38 MAPK activation, apoptosis, and cytotoxicity through GPX4. Our study demonstrated that pyrocatechol is a novel therapeutic agent against cisplatin-induced kidney injury.

Social network distribution of syphilis self-testing among men who have sex with men in China: study protocol for a cluster randomized control trial.

BACKGROUND: Syphilis is a common sexually transmitted infection (STI) among men who have sex with men (MSM). Increasing syphilis testing is important to syphilis control. However, in low- and middle-income countries like China, syphilis testing rates remain low among MSM. We describe a randomized controlled trial protocol to examine the effectiveness of social network distribution approaches of syphilis self-testing among MSM in China. METHODS: We will recruit index and alter MSM. Indexes will be eligible if they: are born biologically male; aged 18 years or above; ever had sex with another man; are willing to distribute syphilis testing packages or referral links to their alters; and willing to provide personal contact information for future follow-up. Three hundred MSM will be recruited and randomly assigned in a 1:1:1 ratio into three arms: standard of care (control arm); standard syphilis self-testing (SST) delivery arm; and referral link SST delivery arm. Indexes will distribute SST packages or referral links to encourage alters to receive syphilis testing. All indexes will complete a baseline survey and a 3-month follow-up survey. Syphilis self-test results will be determined by photo verification via a digital platform. The primary outcome is the mean number of alters who returned verified syphilis testing results per index in each arm. DISCUSSION: The trial findings will provide practical implications in strengthening syphilis self-testing distribution and increasing syphilis testing uptake among MSM in China. This study also empowers MSM community in expanding syphilis testing by using their own social network. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2000036988 . Registered 26 August 2020 - Retrospectively registered.

The PLETHORA Gene Regulatory Network Guides Growth and Cell Differentiation in Arabidopsis Roots.

Organ formation in animals and plants relies on precise control of cell state transitions to turn stem cell daughters into fully differentiated cells. In plants, cells cannot rearrange due to shared cell walls. Thus, differentiation progression and the accompanying cell expansion must be tightly coordinated across tissues. PLETHORA (PLT) transcription factor gradients are unique in their ability to guide the progression of cell differentiation at different positions in the growing Arabidopsis thaliana root, which contrasts with well-described transcription factor gradients in animals specifying distinct cell fates within an essentially static context. To understand the output of the PLT gradient, we studied the gene set transcriptionally controlled by PLTs. Our work reveals how the PLT gradient can regulate cell state by region-specific induction of cell proliferation genes and repression of differentiation. Moreover, PLT targets include major patterning genes and autoregulatory feedback components, enforcing their role as master regulators of organ development.

Interaction between STAT3 gene polymorphisms and smoking on Crohn's disease susceptibility: a case-control study in a Chinese Han population.

AIMS: The aim of this study was to investigate the impact of the signal transducer and activator of transcription 3 (STAT3) gene and additional STAT3 gene-smoking interaction on Crohn's disease (CD) risk based on a Chinese population. METHODS: A total of 1012 participants (491 men, 521 women), were selected, including 502 CD patients and 510 normal controls. The mean age of all participants was 42.3 ± 11.2 years. Logistic regression model was used to examine the association between single nucleotide polymorphism (SNP) of STAT3 and CD risk; the odds ratio (OR) and 95 % confident interval (95 % CI) were calculated. Generalized multifactor dimensionality reduction was employed to analyze the interaction among several SNPs. RESULTS: Logistic analysis showed the significant association between genotypes of variants in two SNP and decreased CD risk, after covariates adjustment. The carriers of homozygous mutant of two SNP polymorphism revealed decreased CD risk than those with wild-type homozygotes; OR (95 % CI) was 0.75 (0.59-0.93) and 0.68 (0.57-0.91), respectively. There was a significant two-locus model (p = 0.0107) involving rs744166 and smoking, indicating a potential gene-environment interaction between rs744166 and smoking. Overall, the cross-validation consistency was 10/10, and the testing accuracy was 62.17 %, and never smokers with TC or CC genotype have the lowest CD risk, compared to smokers with TT genotype; OR (95 % CI) was 0.52 (0.31-0.82), after covariate adjustment. CONCLUSIONS: Our results support an important association of rs744166 and rs4796793 with decreased CD risk, and additional interaction between rs744166 and smoking.

Characterization of Silver Nanoparticles Internalized by Arabidopsis Plants Using Single Particle ICP-MS Analysis.

Plants act as a crucial interface between humans and their environment. The wide use of nanoparticles (NPs) has raised great concerns about their potential impacts on crop health and food safety, leading to an emerging research theme about the interaction between plants and NPs. However, up to this day even the basic issues concerning the eventual fate and characteristics of NPs after internalization are not clearly delineated due to the lack of a well-established technique for the quantitative analysis of NPs in plant tissues. We endeavored to combine a quantitative approach for NP analysis in plant tissues with TEM to localize the NPs. After using an enzymatic digestion to release the NPs from plant matrices, single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) is employed to determine the size distribution of silver nanoparticles (Ag NPs) in tissues of the model plant Arabidopsis thaliana after exposure to 10 nm Ag NPs. Our results show that Macerozyme R-10 treatment can release Ag NPs from Arabidopsis plants without changing the size of Ag NPs. The characteristics of Ag NPs obtained by SP-ICP-MS in both roots and shoots are in agreement with our transmission electron micrographs, demonstrating that the combination of an enzymatic digestion procedure with SP-ICP-MS is a powerful technique for quantitative determination of NPs in plant tissues. Our data reveal that Ag NPs tend to accumulate predominantly in the apoplast of root tissues whereby a minor portion is transported to shoot tissues. Furthermore, the fact that the measured size distribution of Ag NPs in plant tissue is centered at around 20.70 nm, which is larger than the initial 12.84 nm NP diameter, strongly implies that many internalized Ag NPs do not exist as intact individual particles anymore but are aggregated and/or biotransformed in the plant instead.

Spatial coordination between stem cell activity and cell differentiation in the root meristem.

A critical issue in development is the coordination of the activity of stem cell niches with differentiation of their progeny to ensure coherent organ growth. In the plant root, these processes take place at opposite ends of the meristem and must be coordinated with each other at a distance. Here, we show that in Arabidopsis, the gene SCR presides over this spatial coordination. In the organizing center of the root stem cell niche, SCR directly represses the expression of the cytokinin-response transcription factor ARR1, which promotes cell differentiation, controlling auxin production via the ASB1 gene and sustaining stem cell activity. This allows SCR to regulate, via auxin, the level of ARR1 expression in the transition zone where the stem cell progeny leaves the meristem, thus controlling the rate of differentiation. In this way, SCR simultaneously controls stem cell division and differentiation, ensuring coherent root growth.

Shoot apical meristem function in Arabidopsis requires the combined activities of three BEL1-like homeodomain proteins.

In plants, most of the above-ground body is formed post-embryonically by the continuous organogenic potential of the shoot apical meristem (SAM). Proper function of the SAM requires maintenance of a delicate balance between the depletion of stem cell daughters into developing primordia and proliferation of the central stem cell population. Here we show that initiation and maintenance of the Arabidopsis SAM, including that of floral meristems, requires the combinatorial action of three members of the BELL-family of TALE homeodomain proteins, ARABIDOPSIS THALIANA HOMEOBOX 1 (ATH1), PENNYWISE (PNY) and POUND-FOOLISH (PNF). All three proteins interact with the KNOX TALE homeodomain protein STM, and combined lesions in ATH1, PNY and PNF result in a phenocopy of stm mutations. Therefore, we propose that ath1 pny pnf meristem defects result from loss of combinatorial BELL-STM control. Further, we demonstrate that heterodimerization-controlled cellular localization of BELL and KNOX proteins involves a CRM1/exportin-1-mediated nuclear exclusion mechanism that is probably generic to control the activity of BELL and KNOX combinations. We conclude that in animals and plants corresponding mechanisms regulate the activity of TALE homeodomain proteins through controlled nuclear-cytosolic distribution of these proteins.