cDNA cloning and functional characterisation of four antimicrobial peptides from Paa spinosa

Antioxidant peptides, the guardian of life from oxidative stress

Reactive oxygen species (ROS) are produced during oxidative metabolism in aerobic organisms. Under normal conditions, ROS production and elimination are in a relatively balanced state. However, under internal or external environmental stress, such as high glucose levels or UV radiation, ROS production can increase significantly, leading to oxidative stress. Excess ROS production not only damages biomolecules but is also closely associated with the pathogenesis of many diseases, such as skin photoaging, diabetes, and cancer. Antioxidant peptides (AOPs) are naturally occurring or artificially designed peptides that can reduce the levels of ROS and other pro-oxidants, thus showing great potential in the treatment of oxidative stress-related diseases. In this review, we discussed ROS production and its role in inducing oxidative stress-related diseases in humans. Additionally, we discussed the sources, mechanism of action, and evaluation methods of AOPs and provided directions for future studies on AOPs.

Gut microbiota differences during metamorphosis in sick and healthy giant spiny frogs (Paa spinosa) tadpoles

Gut microbiota plays important roles in host nutrition, immunity, development and health; therefore, disruption of the gut microbiota is closely associated with development of diseases in the host. In amphibians, metamorphosis is associated not only with extensive changes in the gut microbiota, but also with high mortality. Therefore, we hypothesized that unsuccessful restructuring of the gut microbiota during metamorphosis was an important factor that caused the fatalities. To test this hypothesis, we investigated the gut microbiota of apparently sick and healthy giant spiny frog tadpoles during metamorphosis, using high-throughput sequencing of the 16S rRNA gene. Our results showed that most dominant phyla differed significantly among developmental stages of sick and healthy Paa spinosa tadpoles. The differences in the dominant genera in sick and healthy tadpoles were the highest at the stage of degeneration of cloacal tube (TDCT). After the metamorphosis, the composition of the gut microbiota was more alike between healthy and sick tadpoles at the stage of forelimb emergence than at TDCT. These results imply that failed restructuring of the gut microbiota during metamorphosis caused the death of P. spinosa tadpoles. These results provided an important reference to prevent the high actual of P. spinosa tadpoles during metamorphosis. SIGNIFICANCE AND IMPACT OF THE STUDY: We investigated the gut microbiota of apparently sick and healthy giant spiny frog (Paa spinosa) tadpoles during metamorphosis, using high-throughput sequencing of the 16S rRNA gene. Our results showed that the differences in the dominant genera in sick and healthy tadpoles were the highest at the stage of degeneration of cloacal tube. After the metamorphosis, the composition of the gut microbiota was alike between healthy and sick tadpoles. These results imply that failed restructuring of the gut microbiota during metamorphosis caused the death of P. spinosa tadpoles.