Search results for "Lethal"

Research on Acute Toxicity and the Behavioral Effects of Methanolic Extract from Psilocybin Mushrooms and Psilocin in Mice

2015

The pharmacological activities and acute toxicity of the psilocin (PC) and dried residues of the crude extracts of psychotropic mushrooms were investigated in mice. The hallucinogenic substances were effectively isolated, by using methanol, from the species of Psilocybe semilanceata and Pholiotina cyanopus, that were collected in the north-east region of Poland. The chemical analysis of these extracts, which was performed by liquid chromatography with mass spectrometry detection (LC-MS), indicated the presence of psilocin and other hallucinogenic substances, including indolealkylamines and their phosphorylated analogues. When the pure psilocin or fungal extracts were used, slight difference…

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…

Presence of a capsule in Vibrio vulnificus biotype 2 and its relationship to virulence for eels

1993

Strains of Vibrio vulnificus biotype 2, isolated from internal organs of diseased European eels as pure cultures of opaque cells, together with some reference strains from Japanese eels, were used in this study. Spontaneous translucent-phase variants were obtained from the corresponding parent strains and compared for a variety of phenotypic traits related to virulence for eels. The rate of colony dissociation from opaque to translucent cells was higher (around 10(-2)) than that observed for translucent to opaque cells (10(-3) to 10(-4)). Electron microscopy with ruthenium red revealed the presence of a capsule of variable thickness on opaque cells, whereas translucent-type colonies had no …

Interaction of Bacillus thuringiensis Cry1 and Vip3A Proteins with Spodoptera frugiperda Midgut Binding Sites

2009

ABSTRACT Vip3Aa, Vip3Af, Cry1Ab, and Cry1Fa were tested for their toxicities and binding interactions. Vip3A proteins were more toxic than Cry1 proteins. Binding assays showed independent specific binding sites for Cry1 and Vip3A proteins. Cry1Ab and Cry1Fa competed for the same binding sites, whereas Vip3Aa competed for those of Vip3Af.

Role of iron, capsule, and toxins in the pathogenicity of Vibrio vulnificus biotype 2 for mice

1994

The virulence mechanisms of Vibrio vulnificus biotype 2 have been studied and compared with those of biotype 1 in mice as the experimental animals. Biotype 2 isolates from European eels were as virulent for mice as biotype 1 strains (50% lethal dose, about 10(5) CFU per mouse); a septicemic infection developed in less than 24 h. These strains had several properties in common with biotype 1 organisms including capsule expression, uptake of various iron sources, and production of exoproteins, whose role in mouse virulence has been demonstrated. We also discuss the implication of biotype 2 strains in human infections.

Hypoglycaemic effect of Spergularia purpurea in normal and streptozotocin-induced diabetic rats

2000

Single and repeated oral administration of the water extracts of Spergularia purpurea (SP) at a dose of 10 mg/kg were tested on hypoglycaemic activity in normal and streptozotocin-induced diabetic rats. In normal rats, the water extract of SP decreased significantly the plasma glucose levels 4 h after single oral administration (P0.01), and one week after repeated oral administration (P0.05). A significant decrease of plasma glucose levels was observed 6 h after a single oral administration of the water extract of S. purpurea in severe hyperglycaemic rats (n=6) from 22.78+/-0.60 to 11.21+/-0.49 mmol/l (P0.001). On other hand, water extract of S. purpurea normalised plasma glucose levels aft…

Changes in selected biochemical parameters in the brain of the fish, Anguilla anguilla (L.), exposed to lindane.

1991

Comparing the acute response to cadmium toxicity of nauplii from different populations ofArtemia

2002

The lethal responses to cadmium of instar II nauplii from eight populations of Artemia belonging to the species Artemia franciscana, Artemia salina, Artemia persimilis, and Artemia parthenogenetica have been compared. Generalized linear models were used to fit mortality. The model indicates that there is a relationship between species, type of population, and mortality rate. The two populations of A. franciscana were the most sensitive to cadmium toxicity (median lethal concentration, LC50, of 93.3-142 mg/L), while the population of A. persimilis was the most resistant (LC50 of 284 mg/L). Differences in the phenotypic variability in each population were assessed through the slope of the mor…

Targeting MYCN in Pediatric and Adult Cancers

2021

The deregulation of theMYCfamily of oncogenes, includingc-MYC,MYCNandMYCLoccurs in many types of cancers, and is frequently associated with a poor prognosis. The majority of functional studies have focused onc-MYCdue to its broad expression profile in human cancers. The existence of highly conserved functional domains betweenMYCNandc-MYCsuggests thatMYCNparticipates in similar activities.MYCencodes a basic helix-loop-helix-leucine zipper (bHLH-LZ) transcription factor (TF) whose central oncogenic role in many human cancers makes it a highly desirable therapeutic target. Historically, as a TF, MYC has been regarded as “undruggable”. Thus, recent efforts focus on investigating methods to indi…

Pharmacological targeting of the novel β-catenin chromatin-associated kinase p38α in colorectal cancer stem cell tumorspheres and organoids

2021

AbstractThe prognosis of locally advanced colorectal cancer (CRC) is currently unsatisfactory. This is mainly due to drug resistance, recurrence, and subsequent metastatic dissemination, which are sustained by the cancer stem cell (CSC) population. The main driver of the CSC gene expression program is Wnt signaling, and previous reports indicate that Wnt3a can activate p38 MAPK. Besides, p38 was shown to feed into the canonical Wnt/β-catenin pathway. Here we show that patient-derived locally advanced CRC stem cells (CRC-SCs) are characterized by increased expression of p38α and are “addicted” to its kinase activity. Of note, we found that stage III CRC patients with high p38α levels display…