Isolation, morphological characterization and screening of antimicrobial activity of heterotropic bacteria from soil collected from Kay Reyna, Lian, Batangas

Eighty (80) bacterial isolates from soil samples collected from Kay Reyna, Lian Batangas were screened and tested for the presence of antimicrobial activities against Candida albicans, Escherichia coli, Psedumonas aeruginosa, Salmonella typhi and Staphylococcus aureus. Nine (9) isolates were found to have antimicrobial activities. Among the nine (9) isolates, two (2) inhibited the growth of both E. coli and S. aureus, whereas three (3) and four (4) isolates inhibited only the growth of S. aureus and E. coli respectively. Isolates which showed a positive inhibitory effect on the test organisms were characterized according to their colonial and microscopic morphologies, after they were subjected to Gram staining

Selective and cross-reactive SARS-CoV-2 T cell epitopes in unexposed humans.

Many unknowns exist about human immune responses to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. SARS-CoV-2-reactive CD4+ T cells have been reported in unexposed individuals, suggesting preexisting cross-reactive T cell memory in 20 to 50% of people. However, the source of those T cells has been speculative. Using human blood samples derived before the SARS-CoV-2 virus was discovered in 2019, we mapped 142 T cell epitopes across the SARS-CoV-2 genome to facilitate precise interrogation of the SARS-CoV-2-specific CD4+ T cell repertoire. We demonstrate a range of preexisting memory CD4+ T cells that are cross-reactive with comparable affinity to SARS-CoV-2 and the common cold coronaviruses human coronavirus (HCoV)-OC43, HCoV-229E, HCoV-NL63, and HCoV-HKU1. Thus, variegated T cell memory to coronaviruses that cause the common cold may underlie at least some of the extensive heterogeneity observed in coronavirus disease 2019 (COVID-19) disease