Філософія популізму як варіант сучасної філософії

We have previously reported on the functional interaction of Lipid II with human alpha-defensins, a class of antimicrobial peptides. Lipid II is an essential precursor for bacterial cell wall biosynthesis and an ideal and validated target for natural antibiotic compounds. Using a combination of structural, functional and in silico analyses, we present here the molecular basis for defensin-Lipid II binding. Based on the complex of Lipid II with Human Neutrophil peptide-1, we could identify and characterize chemically diverse low-molecular weight compounds that mimic the interactions between HNP-1 and Lipid II. Lead compound BAS00127538 was further characterized structurally and functionally; it specifically interacts with the N-acetyl muramic acid moiety and isoprenyl tail of Lipid II, targets cell wall synthesis and was protective in an in vivo model for sepsis. For the first time, we have identified and characterized low molecular weight synthetic compounds that target Lipid II with high specificity and affinity. Optimization of these compounds may allow for their development as novel, next generation therapeutic agents for the treatment of Gram-positive pathogenic infections

Herbicide-Resistant Echinochloa oryzoides and E. phyllopogon in California Oryza sativa Fields

Echinochloa oryzoides and E. phyllopogon have become the most serious weeds in California Oryza sativa since continuous flooding was used to suppress E. crus-galli. Continuous use of a limited number of available graminicides and an increasing number of control failures led to the investigation of herbicide resistance in E. oryzoides and E. phyllopogon. Greenhouse dose-response studies with postemergence (POST) applications of molinate, thiobencarb, fenoxaprop-ethyl, and bispyribac-sodium estimating GR₅₀ (herbicide dose to inhibit growth by 50%) values suggested resistance to all herbicides in two E. phyllopogon accessions and to molinate and thiobencarb in one E. oryzoides accession when compared with susceptible E. phyllopogon and E. oryzoides controls, respectively. No resistance was detected in dose-response studies with propanil. Minimum and maximum ratios (R/S) of the GR₅₀ values of resistant to susceptible E. phyllopogon plants (in two experiments involving two resistant accessions) were 7.8 and \u3e 13.3 for thiobencarb, 2.2 and 4.3 for molinate, 16.5 and 428.7 for fenoxaprop-ethyl, and 2.0 and 12.0 for bispyribac-sodium. Minimum and maximum E. oryzoides R/S ratios (average of two experiments) were 21.9 and 4.6 for thiobencarb and molinate, respectively. A resistant E. phyllopogon (one accession tested) and the susceptible control were killed by POST applications of glyphosate, glufosinate, and clomazone, and by a preemergence application of pendimethalin. Thus, the repeated use of the few available grass herbicides in the predominantly monocultured O. sativa of California has selected for herbicide resistance in E. oryzoides and E. phyllopogon. The introduction of herbicides with new mechanisms of action will be useful to manage herbicide-resistant E. oryzoides and E. phyllopogon. However, cross- and multiple resistance emphasize the need to integrate herbicide use with nonchemical means of weed management

Mechanisms of Resistance to Bispyribac-Sodium in an Echinochloa phyllopogon Accession

Weeds are a major problem for rice production in California, and late watergrass (Echinochloa phyllopogon (Stapf) Koss) is one of the most serious weeds in water-seeded rice. Severe infestations can reduce yields by more than 50%. Flooding only partially controls this weed; thus, farmers rely heavily on herbicides. Resistance to several herbicides, including bispyribac-sodium, an acetolactate synthase (ALS) inhibitor not yet commercially used, has developed in late watergrass populations of California rice. Knowing the mechanisms of bispyribac resistance is relevant to designing herbicide management strategies for delaying resistance development to enhance the successful introduction of this new herbicide. We examined whether an insensitive ALS and cyt P-450-dependent detoxification were possible resistance mechanisms in a bispyribac-sodium-resistant (R) late watergrass population collected in California rice fields, which was previously determined to be resistant to molinate, thiobencarb, and fenoxaprop-ethyl. ALS activity was assayed on leaf extracts from young R and susceptible (S) plants for a range of bispyribac-sodium concentrations, and cross-resistance to another ALS inhibitor, bensulfuron-methyl, was evaluated using whole-plant bioassays. Resistance was not due to reduced ALS sensitivity to bispyribac-sodium in R plants, although the R accession was highly cross-resistant to bensulfuron-methyl. Although S and R plants had similar ALS activity (mg acetoin mg protein−1) without herbicide, more (P \u3c 0.05) leaf protein was extracted from R (5.35 mg g−1 leaf fresh weight) than from S (3.19 mg g−1) plants, and general ALS activity (mg acetoin g leaf fresh weight−1) for all herbicide concentrations was higher in R than in S plants. The cyt P-450 inhibitors piperonyl butoxide and malathion were used for detection of herbicide degradation by cyt P-450 monooxygenation. The addition of these inhibitors strongly enhanced herbicide phytotoxicity toward R plants, suggesting that metabolic degradation of bispyribac-sodium contributed significantly to the observed resistance

Toxicity, antimicrobial and anthelmintic activities of Vernonia guineensis Benth. (Asteraceae) crude extracts

ETHNOPHARMACOLOGICAL RELEVANCE: This study examined the antibacterial, antifungal, and anthelmintic properties of extracts obtained from the plant Vernonia guineensis, a plant commonly used in traditional Cameroonian medicine.MATERIALS AND METHODS: For in vitro studies, 10g of leaf and tuber powder from V. guineensis was extracted separately using dichloromethane, methanol and distilled water. The extracts were dried in vacuo and used for antimicrobial and anthelmintic activity studies. In the antimicrobial assay, extracts were tested against bacterial and fungal organisms including; Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii, Aspergillus fumigatus, Candida albicans and Trichophyton mentagrophytes. In the anthelmintic assay, larval and adult stages of the hookworm Ancylostoma ceylanicum and the mouse nematode Trichuris muris were used. For the acute toxicity test, male and female rats of 150-200g body weight were used in the experiment. The aqueous extract of V. guineensis tubers was administered in 4 doses of 500, 1000, 2000 and 4000mg/kg per group (n=6), respectively, and the control group received distilled water.RESULTS: The crude extracts exhibited weak antibacterial and antifungal activity except for the dichloromethane extract, which showed moderate activity against A. fumigatus (MIC=200?g/ml). In the anthelmintic assay, the organic extracts of the tubers had 100% killing efficacy against T. muris at 2mg/ml in 48h, while the aqueous extract showed no activity. The organic leaf extracts demonstrated potent activity killing 100% of the adult worms 1mg/ml in 24h. The aqueous leaf extract was active at 2mg/ml in 72h, killing 100% of the adult worms. In the acute toxicity test, V. guineensis did not produce any toxic signs or death at the maximum concentration of 4000mg/kg. CONCLUSION: Crude extracts from V. guineensis possess anthelmintic activity against T. muris with only weak antibiotic activity. Acute administration of aqueous extract from V. guineensis tubers did not produce toxic effects in rats. The absence of acute toxicity at the highest concentration tested indicates that the tea decoction from V. guineensis extract is safe at concentrations ?4000mg/kg