Early Cretaceous vegetation and climate change at high latitude: Palynological evidence from Isachsen Formation, Arctic Canada

Quantitative palynology of the marginal marine and deltaic-fluvial Isachsen Formation of the Sverdrup Basin, Canadian Arctic, provides insight into high latitude climate during much of the Early Cretaceous (Valanginian to early Aptian). Detrended Correspondence Analysis of main pollen and spore taxa is used to derive three ecological groupings influenced by moisture and disturbance based on the botanical affinities of palynomorphs: 1) a mixed coniferous assemblage containing both lowland and upland components; 2) a conifer-filicopsid community that likely grew in dynamic lowland habitats; and, 3) a mature dry lowland community composed of Cheirolepidiaceans. Stratigraphic changes in the relative abundance of pollen and spore taxa reflect climate variability in this polar region during the ~20 Mya history of the Isachsen Formation. The late Valanginian was relatively cool and moist and promoted lowland conifer-filicopsid communities. Warming in the Hauterivian resulted in the expansion coniferous communities in well-drained or arid hinterlands. A return to relatively cool and moist conditions in the Barremian resulted in the expansion of mixed lowland communities. This work demonstrates the utility of a multivariate statistical approach to palynology to provide insight into the composition and dynamics of ecosystems and climate of high latitude regions during the Early Cretaceous

Phytochemical analysis and anti-biofilm activity of Carica papaya leaves against Serratia marcescens, Pseudomonas aeruginosa, Vibrio cholera, and Enterococcus faecalis.

Screening plant extracts for discovering new compounds effective in treating bacterial infections has been of great interest to scientists. Phytochemical plant extracts have shown direct antibacterial activity by affecting bacterial growth and metabolism. An EPS (extracellular polymeric substance) matrix protects a biofilm, a structural form of a microbial group. Biofilms are believed to be the major cause of infections and play an essential role in the development of drug resistance. In this study, we investigated the phytochemical composition and anti-biofilm properties of papaya (Carica papaya L.) leaf extract. The preliminary results of our studies indicate that papaya leaf extract contains a variety of bioactive compounds, including triterpenes, steroids, coumarins, quinones, and tannins. These extracts were able to prevent biofilm formation in Serratia marcescens, Pseudomonas aeruginosa, and Vibrio cholera. This study suggests that papaya leaf extracts can be used to develop anti-biofilm agents to control infections caused by these pathogens and prevent the formation of biofilms on medical devices