Germination and growth of Colletotrichum acutatum and Colletotrichum gloeosporioides isolates from coffee in Papua New Guinea and their pathogenicity to coffee berries

The biology and pathogenicity of Colletotrichum acutatum and C. gloeosporioides isolates from infected coffee berries with anthracnose in Papua New Guinea (PNG) was investigated in vitro and in vivo. Optimum germination in vitro occurred at concentrations of 1 x 10 conidia/mL, while germination was inhibited by 1 x 10 conidia/mL. Optimum germination of C. acutatum and C. gloeosporioides conidia occurred at temperatures between 21-29°C and 25-31°C respectively, after 18-24 h incubation periods, between pH5- pH7 and 100% RH. Maximum growth of C. acutatum occurred at 21°C and C. gloeosporioides at 25-31°C. Conidial germination increased in the presence of free water in both species. Colletotrichum acutatum produced abundant secondary conidia in culture. The process of infection of attached and detached coffee berries by conidia of C. gloeosporioides and C. acutatum was investigated and demonstrated to be equivalent for the two species. The optimum temperatures for conidia germination, appressoria formation and anthracnose development ranged between 25-31°C. Conidia germinated after 3-12 h, appressoria were formed after 6-48 h and anthracnose symptoms appeared 6 days after inoculation. Colletotrichum acutatum infected both non-wounded and wounded green and ripe red berries whereas C. gloeosporioides only infected ripe red non-wounded and wounded berries. This is the first report of C. acutatum as an etiological agent of coffee berry anthracnose

A lupane-triterpene isolated from Combretum leprosum Mart. fruit extracts that interferes with the intracellular development of Leishmania (L.) amazonensis in vitro

BACKGROUND: 3beta,6beta,16beta-trihydroxylup-20(29)-ene is a lupane triterpene isolated from Combretum leprosum fruit. The lupane group has been extensively used in studies on anticancer effects; however, its possible activity against protozoa parasites is yet poorly known. The high toxicity of the compounds currently used in leishmaniasis chemotherapy stimulates the investigation of new molecules and drug targets for antileishmanial therapy. METHODS: The activity of 3beta,6beta,16beta-trihydroxylup-20(29)-ene was evaluated against Leishmania (L.) amazonensis by determining the cytotoxicity of the compound on murine peritoneal macrophages, as well as its effects on parasite survival inside host cells. To evaluate the effect of this compound on intracellular amastigotes, cultures of infected macrophages were treated for 24, 48 and 96 h and the percentage of infected macrophages and the number of intracellular parasites was scored using light microscopy. RESULTS: Lupane showed significant activity against the intracellular amastigotes of L. (L.) amazonensis. The treatment with 109 μM for 96 h reduced in 80 % the survival index of parasites in BALB/c peritoneal macrophages. At this concentration, the triterpene caused no cytotoxic effects against mouse peritoneal macrophages. Ultrastructural analyses of L. (L.) amazonensis intracellular amastigotes showed that lupane induced some morphological changes in parasites, such as cytosolic vacuolization, lipid body formation and mitochondrial swelling. Bioinformatic analyses through molecular docking suggest that this lupane has high-affinity binding with DNA topoisomerase. CONCLUSION: Taken together, our results have showed that the lupane triterpene from C. leprosum interferes with L. (L.) amazonensis amastigote replication and survival inside vertebrate host cells and bioinformatics analyses strongly indicate that this molecule may be a potential inhibitor of topoisomerase IB. Moreover, this study opens major prospects for the development of novel chemotherapeutic agents with leishmanicidal activity