Search results for " Lethal Dose"

Biological responses of Rhynchophorus ferrugineus (Coleoptera: Curculionidae) to Steinernema carpocapsae (Nematoda: Steinernematidae).

2013

Rhynchophorus ferrugineus (Olivier 1790) (Coleoptera: Curculionidae) is becoming a serious problem in Mediterranean areas where it is well-adapted, and now is present even in the United States (California). The infestations are primarily in urban areas where chemical control is not advisable and million of Euros are spent to control it. The effects of the entomopathogenic nematode Steinernema carpocapsae (Nematoda: Steinernematidae) on mortality, growth, as well as the immune activity of R. ferrugineus larvae, were investigated. R. ferrugineus mortality exhibited a positive trend with the dosage and duration of exposure to S. carpocapsae. The median lethal dose and median lethal time, impor…

Acute toxicity of several pesticides to rotifer (Brachionus calyciflorus).

1992

Biochemical and toxigenic properties of Vibrio furnissii isolated from a European eel farm

1995

Abstract The present study describes for the first time the isolation of Vibrio furnissii strains from a European eel culture system which are pathogenic for eels ( Anguilla anguilla ) (LD 50 dose, 10 6 cfu/fish). Biochemical characterization of the isolates was performed by API 20E system and by classical numerical taxonomy. Growth at 4 °C, and with 6–8% (w/v) NaCl in a broth medium were necessary to differentiate Vibrio furnissii from Aeromonas species when the API 20E system was used. Virulence for eels of V. furnissii isolates was demonstrated by intraperitoneal injection of living cells. The extracellular products (ECPs) produced by V. furnissii were lethal to elvers and induced some o…

CNS depressant effects, anti-inflammatory activity and anti-cholinergic actions ofSantolina chamaecyparissus extracts

1988

The pharmacological activity of several extracts together with the lyophilized infusion of S. chamaecyparissus ssp. squarrosa were investigated. The lethal dose 50% (LD50), effect on animal metabolism, mechanical and thermic analgesia and spontaneous, anti-inflammatory, and anti-ulcer activity have been determined. Studies on isolated organs (rat duodenum and rat uterus) were also carried out. The hexanic and chloroformic extracts were potent antagonists of the thermic analgesia test; the former extract was also active in the mechanical analgesia test. The chloroformic extract and, to a lesser extent, the ethyl acetate extract and lyophilized infusion demonstrated noteworthy activity as ant…

Photoinduced lethal and sublethal toxicity of retene, a polycyclic aromatic hydrocarbon derived from resin acid, to coregonid larvae

2004

A comparative investigation on the acute phototoxicity of retene to vendace (Coregonus albula) and whitefish (C. lavaretus), both having pelagial larvae in spring, was conducted. To test the concept of early warning of sublethal biomarkers in relation to lethality to posthatch stages, we examined the effects of ultraviolet-B (UV-B) and retene on the levels of cytochrome P4501A (CYP1A) and heat shock protein 70 (HSP70) by exposing the animals to elevated levels of these factors for 48 and 72 h, respectively. Whereas UV-B and retene on their own were not lethal, simultaneous retene and UV-B exposure caused very high mortality to both species. The median lethal concentration (LC50; i.e., the c…

Susceptibility of Spodoptera frugiperda and S. exigua to Bacillus thuringiensis Vip3Aa insecticidal protein

2011

The Vip3Aa protein is an insecticidal protein secreted by Bacillus thuringiensis during the vegetative stage of growth. The activity of this protein has been tested after different steps/protocols of purification using Spodoptera frugiperda as a control insect. The results showed that the Vip3Aa protoxin was stable and retained full toxicity after being subjected to common biochemical steps used in protein purification. Bioassays with the protoxin in S. frugiperda and S. exigua showed pronounced differences in LC(50) values when mortality was measured at 7 vs. 10d. At 7d most live larvae were arrested in their development. LC(50) values of "functional mortality" (dead larvae plus larvae rem…

Pathogenicity of intrathoracically administrated Bacillus thuringiensis spores in Blatta orientalis.

2006

Abstract The ability of Bacillus thuringiensis to produce septicaemia in Periplaneta americana and Blatta orientalis has been investigated. Spores and crystals from several wild-type strains as well as spores of a B. thuringiensis crystal-deficient mutant, were first orally administrated at high doses, and no significant mortality was recorded. Intrathoracic injection of spore suspensions in P. americana revealed that this species is not very susceptible to B. thuringiensis spores. B. orientalis , by contrast, was found to be very susceptible to B. thuringiensis , with a LD 50 of about 35,000 spores, that is similar to that reported on Lepidoptera challenged with parenterally injected B. th…

Lethal toxicity of Lindane on a teleost fish,Anguilla anguillafrom albufera lake (Spain): Hardness and temperature effects

1988

This paper reports the results of toxicity tests conducted using Anguilla anguilla under three different water temperature (15, 22 and 29 degrees C) and two hardness regimes (250 and greater than 600 ppm CaCO3). The 96-h LC50 increased in the experimental medium (p less than 0.05) by an order of magnitude from 0.32 to 0.45 mg/L between 15 and 29 degrees C. However in the natural medium it is similar (p greater than 0.05) (0.54 to 0.55 mg/L) for these same temperatures. The toxicity of Lindane on eels increased when the water hardness decreased. The 24, 48, 72 and 96-h LC50 for this fish in both media is less at 15 degrees C (96-h LC50 = 0.32 and 0.55 mg/L) than at 29 degrees C (96-h LC50 = …

La teneur hépatique en F4-Neuroprostanes : une variable prédictive majeure de la réduction de la plaque d’athérome

2012

Le fichier annexe contient le livre des résumés; Les propriétés athéroprotectrices des acides gras polyinsaturés de type n-3 à longue chaîne (AGPI n-3 LC), et en particulier de l’acide docosahexaénoique (DHA) ont été largement décrites. Néanmoins, les mécanismes d’action restent encore mal connus. Les recherches se sont récemment orientées vers l’identification des métabolites oxygénés issus des AGPI n-3 LC qui sont de plus en plus considérés comme des effecteurs majeurs de leurs effets athéroprotecteurs. Dans ce contexte, une étude dose-réponse de supplémentation en DHA a été réalisée chez un modèle animal d’athérosclérose (souris LDLR-/-) afin d’étudier les relations entre la progression …

A comparative biochemical, pharmacological and immunological study of Clostridium novyi alpha-toxin, C. difficile toxin B and C. sordellii lethal tox…

1991

The three clostridial cytotoxins, i.e. alpha-toxin of C. novyi (Tox alpha-nov), toxin B of C. difficile (ToxB-dif) and lethal toxin of C. sordellii (LT-sor) consist of single peptide chains of about 200,000 (Tox alpha-nov), 250,000 (LT-sor) and 275,000 (ToxB-dif) mol. wts. ToxB-dif and LT-sor but not Tox alpha-nov cross-reacted with rabbit polyclonal antibodies. Toxicity upon i.v. injection in mice was similar (LD50, 100 hr, 50-200 ng/kg) and was characterized by a slowly developing fluid loss into the interstitial space. When injected into the rat paw the toxins caused a delayed local edema lasting for days. In vitro the three toxins provoked a persistent retraction of endothelial cells cu…