Appl. Biosci., Volume 3, Issue 4 (December 2024) – 3 articles

Osteoarthritis is a joint disease that causes pain, stiffness, and reduced joint function because the protective cushioning inside the joints, called cartilage, gradually wears away. This condition is caused by various factors and complex processes in the joint’s environment, involving different types of cells producing factors that can either maintain the joint health or contribute to osteoarthritis. This study aimed to understand the factors influencing both healthy and diseased joints in DDD strategies for the in vitro preconditioning of MSCs. An electronic search in the PubMed, Scopus, and Web of Science databases was carried out using the terms (cartilage OR chondr*) AND (repair OR regeneration OR healing) AND (niche OR microenvironment)) AND (“growth factor” OR GF OR cytokine). Researchers used various methods, including macroscopic examinations, histology, immunohistochemistry, and microCT. Molecules associated with joint inflammation were identified, like macrophage markers, MMP-13, TNF, apoptotic markers, and interleukins. Chondrogenesis-related factors such as aggrecan GAG, collagen type II, and TGF beta family were also identified. This study suggests that balancing certain molecules and ensuring the survival of joint chondrocytes could be crucial in improving the condition of osteoarthritic joints, emphasizing the importance of chondrocyte survival and activity. Future preconditioning methods for MSC- and EV-based therapies can find suitable strategies in the described microenvironments to explore co-culture systems and soluble or extracellular matrix factors. Full article

Metallo-β-lactamases (MBLs) are members of the structurally conserved but functionally diverse MBL-fold superfamily of metallohydrolases. MBLs are a major concern for global health care as they efficiently inactivate β-lactam antibiotics, including the “last-resort” carbapenems, and no clinically suitable inhibitors are currently available. Increasingly, promiscuous β-lactamase activity is also observed in other members of the superfamily, including from viruses, which represents an underexplored reservoir for future pathways to antibiotic resistance. Here, two such MBL-fold enzymes from Bacillus phages, the cyclic mononucleotide-degrading proteins Apyc_Goe3 and Apyc_Grass, are shown to degrade β-lactam substrates efficiently in vitro. In particular, Apyc_Grass displays a distinct preference for carbapenem substrates with a catalytic efficiency that is within one order of magnitude of the clinically relevant MBL NDM-1. Mutagenesis experiments also demonstrate that the loss of a metal-bridging aspartate residue reduces nuclease activity up to 35-fold but improves carbapenemase activity. In addition, we hypothesise that the oligomeric state significantly influences β-lactamase activity by modifying access to the active site pocket. Together, these observations hint at a possible new avenue of resistance via the spread of phage-borne MBL-fold enzymes with β-lactamase activity. Full article

Papaya is a globally important crop, with production primarily based on hermaphrodite plants. Papaya has three sex types—male, female, and hermaphrodite—determined by flower morphology, but this is only distinguishable at the flowering stage. In this study, a recombinase polymerase amplification (RPA) assay was developed and optimized to identify the three sexes of papaya. Recombinant uvsX, uvsY, gp32, and Bsu DNA polymerase were used to study the effects of temperature, reaction time, and sensitivity conditions for RPA reaction efficiency. The optimal conditions were found to be 41 °C and a 30 min reaction time, allowing the detection of the target sex from specific DNA markers, even when using crude extract. This study shows that RPA could be used for sex determination in papaya, and the findings could contribute to developing a point-of-need strategy due to their sensitivity and specificity. Full article