Sequencing the Genome of Indian Flying Fox, Natural Reservoir of Nipah Virus, Using Hybrid Assembly and Conservative Secondary Scaffolding

Optimizing Trilobatin Production via Screening and Modification of Glycosyltransferases

Trilobatin (TBL) is a key sweet compound from the traditional Chinese sweet tea plant (Rubus suavissimus S. Lee). Because of its intense sweetness, superior taste profile, and minimal caloric value, it serves as an exemplary natural dihydrochalcone sweetener. It also has various health benefits, including anti-inflammatory and glucose-lowering effects. It is primarily produced through botanical extraction, which impedes its scalability and cost-effectiveness. In a novel biotechnological approach, phloretin is used as a precursor that is transformed into TBL by the glycosyltransferase enzyme ph-4'-OGT. However, this enzyme's low catalytic efficiency and by-product formation limit the large-scale synthesis of TBL. In our study, the enzyme Mdph-4'-OGT was used to screen 17 sequences across species for TBL synthesis, of which seven exhibited catalytic activity. Notably, PT577 exhibited an unparalleled 97.3% conversion yield within 3 h. We then optimized the reaction conditions of PT577, attaining a peak TBL bioproduction of 163.3 mg/L. By employing virtual screening, we identified 25 mutation sites for PT577, thereby creating mutant strains that reduced by-products by up to 50%. This research enhances the enzymatic precision for TBL biosynthesis and offers a robust foundation for its industrial-scale production, with broader implications for the engineering and in silico analysis of glycosyltransferases.

Reprogrammed Pteropus Bat Stem Cells as A Model to Study Host-Pathogen Interaction during Henipavirus Infection

Bats are natural hosts for numerous zoonotic viruses, including henipaviruses, which are highly pathogenic for humans, livestock, and other mammals but do not induce clinical disease in bats. Pteropus bats are identified as a reservoir of henipaviruses and the source of transmission of the infection to humans over the past 20 years. A better understanding of the molecular and cellular mechanisms allowing bats to control viral infections requires the development of relevant, stable, and permissive cellular experimental models. By applying a somatic reprogramming protocol to Pteropus bat primary cells, using a combination of ESRRB (Estrogen Related Receptor Beta), CDX2 (Caudal type Homeobox 2), and c-MYC (MYC proto-oncogene) transcription factors, we generated bat reprogrammed cells. These cells exhibit stem cell-like characteristics and neural stem cell molecular signature. In contrast to primary fibroblastic cells, these reprogrammed stem cells are highly permissive to henipaviruses and exhibit specific transcriptomic profiles with the particular expression of certain susceptibility factors such as interferon-stimulated genes (ISG), which may be related to viral infection. These Pteropus bat reprogrammed stem cells should represent an important experimental tool to decipher interactions during henipaviruses infection in Pteropus bats, facilitate isolation and production of bat-borne viruses, and to better understand the bat biology.