CRISPR/Cas12a-triggered ordered concatemeric DNA probes signal-on/off multifunctional analytical sensing system for ultrasensitive detection of thalassemia.

Based on CRISPR/Cas12a triggered ordered concatemeric DNA probes, a "on/off" self-powered biosensor is developed to achieve highly sensitive detection of thalassemia gene CD142 through open-circuit potential-assisted visual signal output. The ingeniously constructed glucose oxidase (GOD)-functionalized ordered concatemeric DNA probe structure can significantly amplify signal output, while the coupled CRISPR/Cas12a system is served as a "signal switch" with excellent signal-transducing capabilities. When the ordered concatemeric DNA probe structure is anchored on electrode, the response signal of the sensing system is in the "signal on" mode. While, the presence of the target activates the non-specific cleavage activity of the CRISPR/Cas12a system, causing the sensing system to switch to the "signal off" mode. In the detection system, GOD catalyzes the oxidation of glucose to produce hydrogen peroxide, which further catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to form a color product, enabling visual signal of the target through naked-eye color contrast. By employing a multifunctional analytical mode combining electrochemical and visual signal outputs, accurate determination of the target is achieved, with linear ranges of 0.0001-100 pM, and detection limits of 48.1 aM (S/N = 3). This work provides a reference method for sensitive detection of thalassemia genes and holds great diagnostic potential in biomedical applications.

Identification and molecular docking of novel antioxidant peptides from Candida utilis.

The current trend is the promotion of antioxidants that are beneficial for both health and the environment. Candida utilis have garnered considerable attention due to their commendable attributes such as non-toxicity and the ability to thrive in waste. Therefore, Candida utilis was used as raw material to isolate and identify new antioxidant peptides by employing methods such as ultrafiltration, DEAE Sepharose Fast Flow, and liquid chromatography-tandem mass spectrometry. The antioxidant mechanism of peptides was investigated by molecular docking. The properties of antioxidant peptides were evaluated using a variety of computational tools. This study resulted in the identification of two novel antioxidant peptides. According to the molecular docking results, the antioxidant mechanism of Candida utilis peptides operates by obstructing the entry to the myeloperoxidase activity cavity. The (-) CDOCKER energy of antioxidant peptides was 6.2 and 6.1 kcal/mol, respectively. Additionally, computer predictions indicated that antioxidant peptides exhibited non-toxicity and poor solubility.

Differentiation of bone marrow mesenchymal stem cells into Leydig-like cells with testicular extract liquid in vitro.

Differentiation of Leydig cells plays a key role in male reproductive function. Bone marrow mesenchymal stem cells (BMSCs) have emerged as a potential cell source for generating Leydig-like cells due to their multipotent differentiation capacity and accessibility. This study aimed to investigate the morphological and genetic expression changes of BMSCs during differentiation into Leydig-like cells. Testicular extract liquid, which simulates the microenvironment in vivo, induced the third passage BMSCs differentiated into Leydig-like cells. Changes in cell morphology were observed by microscopy, the formation of lipid droplets of androgen precursor was identified by Oil Red Staining, and the expression of testicular specific genes 3ß-HSD and SF-1 in testicular stromal cells was detected by RT-qPCR. BMSCs isolated from the bone marrow of Sprague-Dawley (SD) rats were cultured for 3 generations and identified as qualified BMSCs in terms of morphology and cell surface markers. After 14 days of induction with testicular tissue lysate, lipid droplets appeared in the cytoplasm of P3 BMSCs by Oil Red O staining. RT-qPCR detection was performed on BMSCs on the 3rd, 7th, 14th, and 21st day after induction. Relative expression levels of 3ß-HSD mRNA significantly increased after 14 days of induction, while the relative expression of SF-1 mRNA increased after 14 days of induction but was not significant. BMSCs can differentiate into testicular interstitial cells with reserve androgen precursor lipid droplets after induction by testicular tissue lysate. The differentiation ability of BMSCs provides the potential to reconstruct the testicular microenvironment and is expected to fundamentally improve testicular function and provide new treatment options for abnormal spermatogenesis diseases.