Khoa học & Công nghệ

This study developed a novel biocontrol strategy using an alginate-encapsulated thermostable mutant chitinase (I168L) combined with zinc oxide nanoparticles (ZnONPs) to enhance enzyme stability and antifungal efficacy against Colletotrichum spp. DH31.1. The primary objective was to improve the enzyme's activity and extend its storage life. The Alg-I168L-ZnONPs complex and free I168L enzyme were synthesized and characterized, then evaluated for stability and antifungal activity after one-month storage at 4 °C. Results showed that encapsulation significantly enhanced the enzyme's thermal and storage stability, maintaining over 89 % relative activity even after 30 days at room temperature and over 90 % after one month at 4 °C. Furthermore, the Alg-I168L-ZnONPs complex consistently exhibited higher chitinase activity in phosphate buffer compared to water. Crucially, in postharvest trials on dragon fruits, the Alg-I168L-ZnONPs complex demonstrated superior antifungal efficacy, effectively preventing and treating Colletotrichum spp. DH31.1 infection at both 28 °C and 35 °C, with disease lesions being almost negligible. These findings highlight the significant potential of this stable and highly effective enzyme nanocomplex as an environmentally friendly alternative for preventing postharvest fungal diseases.

Phan Rang sheep is a term used to collectively refer to the sheep raised in the central Vietnam provinces of Ninh Thuan and Binh Thuan. Given the extreme weather conditions of their habitat, Phan Rang sheep are assumed to be heat-resilient. With climate change’s mounting challenges, the sheep have become a focus of government-led breeding and conservation initiatives. However, there is a critical knowledge gap regarding the sheep’s genetic information, including their origins, diversity, population structure, and genetics, as well as the morphological basis of their adaptive traits. This gap has hindered the development of breeding programs and genetic resource conservation efforts. In an effort to contribute to filling this knowledge gap, we employed a two-fold approach to investigate Phan Rang sheep’s morphometrics and genetic lineages. First, we collected body conformational data to facilitate the quick identification of purebred individuals. Secondly, we collected and analyzed the mitochondrial DNA control region (D-loop) and the Y chromosome SRY and SRYM18 sequences to elucidate the maternal and paternal lineages of the sheep. Of the sheep analyzed for the D-loop, approximately one-third belonged to haplogroup A, while the remainder belonged to haplogroup B. For the paternal lineage, two main Y haplotypes, H5 and H6, were identified. Overall, the findings supported the hypothesis of dual origins for the Phan Rang sheep.

Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC11274324/

This study aimed to improve the thermal stability of 42 kDa chitinase from T. asperellum SH16 produced in N. benthamiana through site-directed mutagenesis for application in post-harvest fruit and vegetable preservation. In this work, thermostable mutants were predicted using bioinformatics tools, gene expression was analyzed by SDS-PAGE and Western blot, chitinase activity was determined spectrophotometrically, and the antifungal activity of chitinase was evaluated through inhibition of mycelial growth. The results showed that six selected mutants were successfully expressed in N. benthamiana and had in vitro antifungal activity against Colletotrichum siamense AD1.2. Among them, mutant I168L has a higher optimal temperature, thermal stability, and enzymatic activity than native chitinase and other mutants. Further analysis showed that, after 6 h of treatment at 40 °C, the relative activity of I168L remained about 50%, but that of native chitinase was only more than 15%. Besides, the I168L mutant could maintain a relative activity of about 78% and 50% after 30 min at 60ºC and 70ºC, while the native chitinase had only 38% and 12%, respectively. The Km and Vmax of the I168L mutant were both lower than those of native chitinase: 6.99 mg/mL and 254 units/mg vs. 11.24 mg/mL and 512 units/mg, respectively. Mutant I168L showed the ability to prevent and treat chili anthracnose disease caused by C. siamense CH26.1, which was many times stronger than the native chitinase at 35ºC. This finding suggests that the thermostable chitinase, I168L, has potential for applications in post-harvest fruit and vegetable preservation.

Link: https://link.springer.com/article/10.1007/s11240-024-02870-x