The role in virulence of Actinobacillus pleuropneumoniae urease activity was investigated. A urease-negative mutant was isolated following transposon mutagenesis with a mini-Tn10 derivative. Both the parent strain and the urease-negative mutant exhibited identical LD50 values in a murine infection model. Pig challenge confirmed that the urease-negative mutant was fully virulent, since experimen...

Sitophilus oryzae (Linnaeus) is a major pest of stored grain across Southeast Asia and is of increasing concern in other regions due to the advent of strong resistance to phosphine, the fumigant used to protect stored grain from pest insects. We investigated the inheritance of genes controlling resistance to phosphine in a strongly resistant S. oryzae strain (NNSO7525) collected in Australia an...

The anesthetic effects of clove-oil-derived eugenol were studied in the zebrafish, Danio rerio (Hamilton). Acute lethality and the effects of exposures to various dosages of eugenol were measured. The estimated 96-h LC50 for eugenol was 21 ppm. Times to induction and recovery from anesthesia were measured and compared with MS-222 under similar conditions. Eugenol induced anesthesia faster and a...

Malaria and filariases are prevalent in Sudan and their control depends largely on preventive measures against mosquito vectors. The present work aimed to investigate the larvicidal, adults emergence inhibition and oviposition deterrent effects of aqueous extracts from leaves of Ricinus communis L. against the mosquitoes, Anopheles arabiensis and Culex quinquefasciatus as a biological control m...

The effects of pyriproxyfen were tested against a local population of Aedes aegypti (L.) in Iquitos, Perú. Bioassays showed that, when applied to late instars, pyriproxyfen prevented adult emergence at extremely low concentrations (LC50 = 0.012 ppb). There was no adult emergence from water sampled from storage tanks that had been seeded with the equivalent of 50-83 ppb (AI) pyriproxyfen. Five m...

Biosurfactants are microbial metabolites with possible applications in various industrial sectors that are considered ecofriendly molecules. In recent years, some studies identified these compounds as alternatives for the elimination of vectors of tropical diseases, such as Aedes aegypti. The major bottlenecks of biosurfactant industrial production have been the use of conventional raw material...

Two freshwater fishes, Rasbora sumatrana (Cyprinidae) and Poecilia reticulata (guppy) (Poeciliidae) were exposed for a four-day period in the laboratory condition to a range of copper (Cu) and cadmium (Cd) concentrations. Mortality was assessed and median lethal concentrations (LC50) were calculated. LC50 increased with decrease in mean exposure times for both metals. For R. sumatrana, LC50s fo...

The aim of the study was to investigate the influence of administration of chlorpyrifos and/or enrofloxacin on the activity of chosen antioxidative enzymes i.e.: superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in erythrocytes of rats. Chlorpyrifos was administered by stomach tube during 28 days at a dose of 3 mg/kg bw (0.02 LD50), and enrofloxacin was administered by...

Citrus Variegated Chlorosis (CVC) is an economically important, destructive disease in Brazil and is caused by Xylella fastidiosa and transmitted by sharpshooter insects. In this study, the efficacy of the fungus Metarhizium anisopliae in controlling the sharpshooter Oncometopia facialis was studied by bioassay conditions. In the bioassay, insects were sprayed with a suspension containing 5 X 1...

OBJECTIVE To evaluate acute toxic effect of ibogaine and noribogaine on the survival of mice and determine median lethal doses of the substances mentioned. MATERIAL AND METHODS White laboratory mice were used for the experiments. Ibogaine and noribogaine were administered intragastrically to mice via a stomach tube. Control animals received the same volume of saline. The median lethal dose wa...