Heat-shock transcription factor HsfA8a regulates heat stress response in Sorbus pohuashanensis.

MAIN CONCLUSION: The SpHsfA8a upregulated expression can induce the expression of multiple heat-tolerance genes, and increase the tolerance of Arabidopsis thaliana to high-temperature stress. Sorbus pohuashanensis is an ornamental tree used in courtyards. However, given its poor thermotolerance, the leaves experience sunburn owing to high temperatures in summer, severely affecting its ornamental value. Heat-shock transcription factors play a critical regulatory role in the plant response to heat stress. To explore the heat-tolerance-related genes of S. pohuashanensis to increase the tree's high-temperature tolerance, the SpHsfA8a gene was cloned from S. pohuashanensis, and its structure and expression patterns in different tissues and under abiotic stress were analyzed, as well as its function in heat tolerance, was determined via overexpression in Arabidopsis thaliana. The results showed that SpHsfA8a encodes 416 amino acids with a predicted molecular weight of 47.18 kDa and an isoelectric point of 4.63. SpHsfA8a is a hydrophilic protein without a signal peptide and multiple phosphorylation sites. It also contains a typical DNA-binding domain and is similar to MdHsfA8a in Malus domestica and PbHsfA8 in Pyrus bretschneideri. In S. pohuashanensis, SpHsfA8a is highly expressed in the roots and fruits and is strongly induced under high-temperature stress in leaves. The heterologous expression of SpHsfA8a in A. thaliana resulted in a considerably stronger growth status than that of the wild type after 6 h of treatment at 45 °C. Its proline content, catalase and peroxidase activities also significantly increased, indicating that the SpHsfA8a gene increased the tolerance of A. thaliana to high-temperature stress. SpHsfA8a could induce the expression of multiple heat-tolerance genes in A. thaliana, indicating that SpHsfA8a could strengthen the tolerance of A. thaliana to high-temperature stress through a complex regulatory network. The results of this study lay the foundation for further elucidation of the regulatory mechanism of SpHsfA8a in response of S. pohuashanensis to high-temperature stress.

Enhancing SN38 prodrug delivery using a self-immolative linker and endogenous albumin transport.

Enhancing the delivery and release efficiency of hydroxyl agents, constrained by high pKa values and issues of release rate or unstable linkage, is a critical challenge. To address this, a self-immolative linker, composed of a modifiable p-hydroxybenzyl ether and a fast cyclization adapter (N-(ortho-hydroxyphenyl)-N-methylcarbamate) was strategically designed, for the synthesis of prodrugs. The innovative linker not only provides a side chain modification but also facilitates the rapid release of the active payloads, thereby enabling precise drug delivery. Particularly, five prodrug model compounds (J1, J2, J3, J5 and J6) were synthesized to evaluate the release rates by using ß-glucuronic acid as trigger and five hydroxyl compounds as model payloads. Significantly, all prodrug model compounds could efficiently release the hydroxyl payloads under the action of ß-glucuronidase, validating the robustness of the linker. And then, to assess the drug delivery and release efficiency using endogenous albumin as a transport vehicle, J1148, a SN38 prodrug modified with maleimide side chain was synthesized. Results demonstrated that J1148 covalently bound to plasma albumin through in situ Michael addition, effectively targeting the tumor microenvironment. Activated by ß-glucuronidase, J1148 underwent a classical 1, 6-elimination, followed by rapid cyclization of the adapter, thereby releasing SN38. Impressively, J1148 showed excellent therapeutic efficacy against human colonic cancer xenograft model, leading to a significant reduction or even disappearance of tumors (3/6 of mice cured). These findings underscore the potential of the designed linker in the delivery system of hydroxyl agents, positioning it at the forefront of advancements in drug delivery technology.

Cumulative childhood trauma and cybervictimization among Chinese college students: Internet addiction as a mediator and roommate relationships as a moderator.

Existing studies have found that childhood trauma is a risk predictor of cybervictimization, but few studies have explored the relationship between cumulative childhood trauma and college students' cybervictimization. This study explored the relationship and the roles of Internet addiction and Internet victimization between them. A total of 854 college students (568 females, M age = 18.92 years, SD = 0.86) completed a survey including the Short Form of Childhood Trauma Questionnaire, the Cyberbullying Inventory, the Young's Internet Addiction Scale, and the revised Roommate Relationships Questionnaire. The results showed that: (1) cumulative childhood trauma was significantly positively associated with cybervictimization; (2) Internet addiction played a mediating role between cumulative childhood trauma and cybervictimization; and (3) roommate relationships played a moderating role between cumulative childhood trauma and cybervictimization, as well as Internet addiction and cybervictimization. The research findings provide a theoretical and practical basis for the prevention and intervention of college students' cybervictimization.

Creation of an Industrial Bacillus thuringiensis Strain With High Melanin Production and UV Tolerance by Gene Editing.

Bacillus thuringiensis produces insecticidal crystal proteins (ICPs) which exhibit strong insecticidal toxicity. But when used in the field, ICPs would be destroyed by ultraviolet (UV) radiation in sunlight, thus decreasing the insecticidal activity and shortening the persistence. To improve the duration of B. thuringiensis preparations, we endowed a highly toxic industrial B. thuringiensis HD-1 with UV tolerance by making it produce melanin, a pigment that absorbs UV radiation. In B. thuringiensis, melanin is derived from homogentisate (HGA), an intermediate in the tyrosine pathway. And the absence of homogentisate-1,2-dioxygenase (HmgA) will lead to the formation of melanin. In this study, we used the CRISPR/Cas9 system to knock out the hmgA gene and obtained a melanin-producing mutant HD-1-ΔhmgA from strain HD-1. The melanin yield by mutant HD-1-ΔhmgA reached 3.60 mg/mL. And the anti-UV test showed that melanin serves as a protection to both the organism and the ICPs. After UV irradiation for 3 h, mutant HD-1-ΔhmgA still had an 80% insecticidal activity against the cotton bollworm, Helicoverpa armigera, while the control line only had about 20%. This study creates a light-stable biopesticide prototype based on a classic industrial strain that can be applied directly and takes the melanin-producing strain as a concept to improve the preparation validity.

Physiological and transcriptomic analyses characterized high temperature stress response mechanisms in Sorbus pohuashanensis.

Sorbus pohuashanensis (Hance) Hedl. is a Chinese native alpine tree species, but the problem of introducing S. pohuashanensis to low altitude areas has not been solved. In this study, we aimed to explore the molecular regulatory network of S. pohuashanensis in response to high-temperature stress using RNA-Sequencing technology and physiological and biochemical determination. Based on transcriptomic data, we obtained 1221 genes (752 up-regulated and 469 down-regulated) that were differentially expressed during 8 h 43℃ treatment and candidate genes were related to calcium signaling pathway, plant hormone signal transduction, heat shock factors, chaperones, ubiquitin mediated proteolysis, cell wall modification, ROS scavenging enzymes, detoxification and energy metabolism. The analysis of high temperature response at the physiological level and biochemical level were performed. The chlorophyll fluorescence parameters of leaf cells decreased, the content of osmotic regulators increased, and the activity of ROS scavenging enzymes decreased. The molecular regulatory network of S. pohuashanensis in response to high-temperature stress was preliminarily revealed in this study, which provides fundamental information improving introducing methods and discovering heat-tolerant genes involved in high-temperature stress in this species and provides a reference for other plants of the genus Sorbus.

Randomized clinical trial comparing whitening strips, paint-on gel and negative control.

PURPOSE: To evaluate efficacy and safety of peroxide-containing whitening strips and a paint-on gel relative to a non-peroxide experimental control. METHODS: After informed consent, 52 healthy adults in Shanghai, China were randomized to one of three treatment groups: 6% hydrogen peroxide whitening strips (Crest Whitestrips), 5.9% hydrogen peroxide paint-on gel (Colgate Simply White), or water rinse which served as a negative experimental control. Strip use was twice daily over 7 days, while the paint-on gel and rinse were used twice daily over 14 days. Efficacy was measured from standard digital images of the maxillary anterior teeth, and safety was assessed from interview and intraoral examination. RESULTS: Whitening strips provided the greatest end-of-treatment reduction in yellowness (Deltab*), with adjusted means +/- standard errors of -1.72 +/- 0.18 for the strip group, -0.48 +/- 0.10 for the paint-on gel group, and 0.13 +/- 0.09 for the water rinse group. For DeltaL* (lightness), end-of-treatment adjusted means +/- standard errors were 1.88 +/- 0.21 for the strip group, 0.60 +/- 0.15 for the paint-on gel, and -0.10 +/- 0.18 for the negative control. Groups differed significantly (P< 0.007) with respect to Deltab* and DeltaL* at end-of-treatment, as well as other color parameters. All treatments were well-tolerated.