Isolation of farnesylhydroquinones from the basidiomycete Ganoderma pfeifferi

Two farnesylhydroquinones were isolated from the fruiting bodies of Ganoderma pfeifferi,farnesylhydroquinone(1)and the new compound ganomycin K(2),(5S)-3-[(E)-7,8-dihydroxy-4,8-dimethylnon-3-enyl]-5-(2,5-dihydroxyphenyl)-furan-2(5H)-one.The structures of 1 and 2 were determined on the basis of mass spectrometric and NMR spectroscopic evidence.The antibacterial activity of the isolated compounds was neglectable.

Laboratory assessment of the molluscicidal and cercariacidal activities of Balanites aegyptiaca

Objective:To assess the molluscicidal and cercariacidal activities of aqueous extracts of Balanites aegyptiaca(B.aegyptiaca)against EthiopianBiomphalaria pfeifferi(B.pfeifferi),Lymnaea natalensis(L.natalensis)and Schistosoma mansoni(S.mansoni)cercariae.Methods:Extracts of seeds,endocarp,mesocarp,and fruit of B.aegyptiacawere tested for their activities against adultB.pfeifferiandL.natalensis.The cercariacidal activity of the seeds of the plant was also evaluated againstS.mansoni.Bioassays were carried out following the methods recommended by WHO.Snail mortalities were compared between each plant part and snail species,and LC50and LC90values for the plant parts tested were computed.The cercariacidal activity of the plant was assessed by exposing the mice to the cercariae pre-exposed to aqueous extract of B.aegyptiacaseeds.Results:For the molluscicidal activities of seeds,endocarp,mesocarp and whole fruit,the LC50values againstB.pfeifferiwere 56.32,77.53,65.51 and 66.63 mg/L,respectively,while the respective LC90values were 77.70,120.04,89.50 and 97.55 mg/L.Similarly,the LC50values for the seeds,endocarp,mesocarp and whole fruit againstL.natalensiswere 80.33,92.61,83.52 and 87.84mg/L,respectively,while the respective LC90values were 102.30,138.21,115.42 and 127.69 mg/L.B.pfeifferiwere found to be more susceptible toB.aegyptiacathanL.natalensis.S.mansoni cercariae exposed to 15 mg/L of extract of seeds were incapable of infecting mice.The mean egg load of tissue was reduced in mice infected with the cercariae exposed to 5 and 10 mg/L of the extract.Conclusions:The aqueous extracts of different parts ofB.aegyptiacaexhibited reasonable molluscicidal activity againstB.pfeifferiandL.natalensis,as well as cercariacidal activity againstS.mansonicercariae.However,comprehensive laboratory evaluation is recommended prior to field tests of the plant parts since their impact on other aquatic biota is not known.

Environmental determinants of distribution of freshwater snails and trematode infection in the Omo Gibe River Basin,southwest Ethiopia

Background:Determination of infection rates of snail populations is one of the basic tools for epidemiological studies of snail borne diseases.In this study,we opted to determine the trematode infection of freshwater snails in the Omo-Gibe River Basin,southwest Ethiopia.Methods:We collected snail samples from 130 observation sites in lakes,wetlands,rivers,reservoirs and irrigation canals surveyed during the dry season(March to May)in 2016.The snail samples were examined for trematode infections by cercarial shedding immediately after collection.Habitat conditions,water quality,human water contact practices and other human activities were assessed at each survey site.A redundancy analysis(RDA)was used to examine the relationship between cercarial infection and environmental variables.The statistical significance of eigenvalues and cercariae-environment correlations generated by the RDA were tested using Monte Carlo permutations at 499 permutations.Results:A total of 3107 snails belonging to five species were collected.The most abundant species was Biomphalario pfeifferi,representing 66%of the total collection.Overall,109(3.6%)of the snails were found infected with trematodes(cercariae).Biompholario pfeifferi was found to be the most highly infected,accounting 85%of all infected snails.A total of eight morphologically different types of cercariae were recorded,which included:Echinostoma cercariae,brevifurcate apharyngeate distome cercariae,amphistome cercariae,brevifurcate apharyngeate monostome cercariae,xiphidiocercariae,longifurcate pharyngeate distome cercariae,strigea cercariae and unidentified cercariae.Brevifurcate apharyngeate distome cercariae,and Echinostoma cercariae were the most abundant cercariae,accounting for 36 and 34%of all infection,respectively.The mean concentration of water conductivity and 5 days biological oxygen demand were higher in irrigation canals and lake sampling points.Human activities such as open field defecation,urination,livestock grazing,farming,and swimming were highly correlated with trematode infection.Conclusions:The abundance,occurrence and infection rates of snail species were largely influenced by water physicochemical quality,sanitation and water contact behaviour of the inhabitants.Human activities,such as open field defecation and urination,livestock grazing,farming,and swimming were important predictors of the abundance of cercariae.Therefore,awareness creation should be implemented for proper containment of excreta(urine and faeces)and reducing human and animal contacts with surface waters to reduce snail-borne disease transmission.