Neuroprotective Effects of Lindleyin on Hydrogen Peroxide-Induced Cell Injury and MPTP-Induced Parkinson's Disease in C57BL/6 Mice.

Oxidative stress (OS) is a crucial factor influencing the development of Parkinson's disease (PD). Here we first reported that Lindleyin (Lin), one of the major components of rhubarb, possessed neuroprotective effects against H2O2-induced SH-SY5Y cell injury and MPTP-induced PD of C57BL/6 mice. The results showed that Lin can decrease cell death and apoptotic rate induced by H2O2 through inhibiting mitochondrial apoptotic pathway and increasing the activities of SOD, GSH-Px, and CAT as well as decreasing the level of MDA. In addition, in vivo studies showed that oral administration of Lin (5 or 20 mg/kg) showed significant change in motor function deficits, antioxidant enzyme activities, apoptotic pathway, and tyrosine hydroxylase expression. Our results reveal that Lin might be a promising anti-PD agent by reducing OS and apoptosis.

Campylobacter Prevalence and Quinolone Susceptibility in Feces of Preharvest Feedlot Cattle Exposed to Enrofloxacin for the Treatment of Bovine Respiratory Disease.

Campylobacter spp. can be pathogenic to humans and often harbor antimicrobial resistance genes. Data on resistance in relation to fluoroquinolone use in beef cattle are scarce. This cross-sectional study of preharvest cattle evaluated Campylobacter prevalence and susceptibility to nalidixic acid and ciprofloxacin in feedlots that previously administered a fluoroquinolone as primary treatment for bovine respiratory disease. Twenty fresh fecal samples were collected from each of 10 pens, in each of five feedlots, 1-2 weeks before harvest. Feces were cultured for Campylobacter using selective enrichment and isolation methods. Genus and species were confirmed via PCR. Minimum inhibitory concentrations (MICs) of ciprofloxacin and nalidixic acid were determined using a micro-broth dilution method and human breakpoints. Antimicrobial use within each pen was recorded. Data were analyzed using generalized linear mixed-models (prevalence) and survival analysis (MICs). Overall, sample-level prevalence of Campylobacter was 27.2% (272/1000) and differed significantly among feedlots (p < 0.01). Campylobacter coli was the most common species (55.1%; 150/272), followed by Campylobacter hyointestinalis (42.6%; 116/272). Within-pen prevalence was not significantly associated with the number of fluoroquinolone treatments, sex, body weight, or metaphylaxis use, but was associated with the number of days cattle were in the feedlot (p = 0.03). The MICs for the majority of Campylobacter isolates were above the breakpoints for nalidixic acid (68.4%; 175/256) and for ciprofloxacin (65.6%; 168/256). Distributions of MICs for nalidixic acid (p ≤ 0.01) and ciprofloxacin (p ≤ 0.05) were significantly different among feedlots, and by Campylobacter species. However, fluoroquinolone treatments, sex, body weight, days on feed, and metaphylaxis were not significantly associated with MIC distributions within pens. We found no evidence that the number of fluoroquinolone treatments within feedlot pens significantly affected the within-pen fecal prevalence or quinolone susceptibilies of Campylobacter in feedlots that used a fluoroquinolone as primary treatment for bovine respiratory disease.

[Toxic effects of high concentrations of ammonia on Euglena gracilis].

Ammonia is among the common contaminants in aquatic environments. The present study aimed at evaluation of the toxicity of ammonia at high concentration by detecting its effects on the growth, pigment contents, antioxidant enzyme activities, and DNA damage (comet assay) of a unicellular microalga, Euglena gracilis. Ammonia restrained the growth of E. gracilis, while at higher concentrations, ammonia showed notable inhibition effect, the growth at 2 000 mg x L(-1) was restrained to 55.7% compared with that of the control; The contents of photosynthetic pigments and protein went up with increasing ammonia dosage and decreased when the ammonia concentration was above 1000 mg x L(-1); In addition, there was an obvious increase in SOD and POD activities, at higher concentration (2 000 mg x L(-1)), activities of SOD and POD increased by 30.7% and 49.4% compared with those of the control, indicating that ammonia could promote activities of antioxidant enzymes in E. gracilis; The degree of DNA damage observed in the comet assay increased with increasing ammonia concentration, which suggested that high dose of ammonia may have potential mutagenicity on E. gracilis.

Occurrence of tcrB, a transferable copper resistance gene, in fecal enterococci of swine.

High concentration of copper, fed as copper sulfate, is often used to increase growth rates in swine. Bacteria exposed to copper may acquire resistance, and in Enterococcus faecium and Enterococcus faecalis, a plasmid-borne transferable copper resistance (tcrB) gene that confers copper resistance has been reported. Our objectives were to determine the occurrence of tcrB in fecal enterococci from weaned piglets fed diets with a normal supplemental level (16.5 ppm) or an elevated supplemental level (125 ppm) of copper and to determine the association of tcrB with copper, erythromycin, and vancomycin resistance. A total of 323 enterococcal isolates were examined and 15 (4.6%) isolates (14 E. faecium and 1 E. faecalis) were positive for tcrB. Fifteen tcrB-positive and 15 randomly chosen tcrB-negative isolates from piglets fed the normal supplemental level of copper were tested for erm(B), tet(M), vanA, and vanB genes and susceptibilities to copper, erythromycin, tetracyclines, and vancomycin. All tcrB-positive and -negative isolates contained erm(B) and tet(M), but not vanA and vanB. The mean minimum inhibitory concentration of copper for tcrB-positive (21.1 mM) was higher (p < 0.001) compared with tcrB-negative isolates (6.1 mM). All isolates were resistant to erythromycin and tetracyclines and susceptible to vancomycin. The transferability of the tcrB gene from tcrB-positive strains to tcrB-negative strains was demonstrated by conjugation. The potential link between tcrB and antibiotic resistance genes and the propensity of enterococci to transfer tcrB to other strains raises the possibility that copper supplementation may exert selection pressure for antibiotic-resistant enterococci. This study is the first report on the occurrence of the tcrB gene in enterococci isolated from swine in the United States.