Pharmacological effects of monoterpene carveol on the neuromuscular system of nematodes and mammals

The control of parasitic nematode infections relies mostly on anthelmintics. The potential pharmacotherapeutic application of phytochemicals, in order to overcome parasite resistance and enhance the effect of existing drugs, is becoming increasingly important. The antinematodal effects of carveol was tested on the free-living nematode Caenorhabditis elegans and the neuromuscular preparation of the parasitic nematode Ascaris suum. Carveol caused spastic and geraniol atonic paralysis in C. elegans. In A. suum carveol potentiated contractions induced by acetylcholine (ACh) and this effect was confirmed with two-electrode voltage-clamp electrophysiology on the A. suum nicotinic acetylcholine receptor expressed in Xenopus oocytes. However, potentiating effect of carveol on ACh-induced contractions was partially sensitive to atropine, indicates a dominant nicotine effect but also the involvement of some muscarinic structures. The effects of carveol on the neuromuscular system of mammals are also specific. In micromolar concentrations, carveol acts as a non-competitive ACh antagonist on ileum contractions. Unlike atropine, it does not change the EC50 of ACh but reduces the amplitude of contractions. Carveol caused an increase in Electrical Field Stimulation-evoked contractions of the isolated rat diaphragm, but at higher concentrations it caused an inhibition. Also, carveol neutralized the mecamylamine-induced tetanic fade, indicating a possibly different pre-and post-synaptic action at the neuromuscular junction

Gelatinolytic matrix metalloproteinases activities in canine and feline effusions – A pilot study

Conference Abstract

Alkaline phosphatase activity and isoforms in canine and feline effusions –A pilot study

Background: Bone, liver and corticosteroid‐induced ALP isoforms are present in dog serum; liver isoform is present in cat serum. Neoplastic cells can produce atypical ALP isoforms. Objective: We hypothesized that ALP activity and isoforms in canine and feline effusions might reflect the dominant pathogenesis of fluid accumulation. Methods: Dog (n = 9) and cat (n = 7) peritoneal/pleural effusions were analyzed for ALP isoforms using zymography. Results of rou‐ tine effusion analysis were obtained from the laboratory (Vetlab, Belgrade) database. Results: Effusions were classified as modified transudate (MT) (n = 4), exudate (n = 3), neoplastic (n = 4), feline infectious peritonitis (n = 3), and chylous (n = 1). Two ALP isoforms were detected: type‐1 and type‐2. In dogs, median ALP activity was higher in MTs (118 U/L, range 61‐860 U/L) compared to exudates (22 U/L, 16‐116 U/L), and neoplastic effusions (14 U/L, 10‐22 U/L) (Kruskall‐Wallis, P = .067); 3 MTs had type‐1 isoform and one had both ALP isoforms. Neoplastic effusions had variable patterns: no detectable isoforms (n = 2), type‐1 isoform (n = 1), and both isoforms (n = 1). In cats, an exudate with both isoforms had the highest ALP activity, the chylous effusion had type‐2 isoform, and FIP effusions had undetectable ALP activity. Overall ALP activity was not correlated with effusion TP concentration or TNCC. Conclusions: Different patterns of ALP isoforms in effusions are observed in canine and feline effusions that might indicate under‐ lying pathogenesis. Future studies are needed to determine spe‐ cific ALP isoforms in effusions that result from known underlying diseases

Biofilm-forming ability and infection potential of Pseudomonas aeruginosa strains isolated from animals and humans

Pseudomonas aeruginosa has been amongst the top 10 'superbugs' worldwide and is causing infections with poor outcomes in both humans and animals. From 202 P. aeruginosa isolates (n = 121 animal and n = 81 human), 40 were selected on the basis of biofilm-forming ability and were comparatively characterized in terms of virulence determinants to the type strain P. aeruginosa PAO1. Biofilm formation, pyocyanin and hemolysin production, and bacterial motility patterns were compared with the ability to kill human cell line A549 in vitro. On average, there was no significant difference between levels of animal and human cytotoxicity, while human isolates produced higher amounts of pyocyanin, hemolysins and showed increased swimming ability. Non-parametric statistical analysis identified the highest positive correlation between hemolysis and the swarming ability. For the first time an ensemble machine learning approach used on the in vitro virulence data determined the highest relative predictive importance of the submerged biofilm formation for the cytotoxicity, as an indicator of the infection ability. The findings from the in vitro study were validated in vivo using zebrafish (Danio rerio) embryos. This study highlighted no major differences between P. aeruginosa species isolated from animal and human infections and the importance of pyocyanin production in cytotoxicity and infection ability. © FEMS 2018

Biofilm-forming ability and infection potential of Pseudomonas aeruginosa strains isolated from animals and humans

Pseudomonas aeruginosa has been amongst the top 10 'superbugs' worldwide and is causing infections with poor outcomes in both humans and animals. From 202 P. aeruginosa isolates (n = 121 animal and n = 81 human), 40 were selected on the basis of biofilm-forming ability and were comparatively characterized in terms of virulence determinants to the type strain P. aeruginosa PAO1. Biofilm formation, pyocyanin and hemolysin production, and bacterial motility patterns were compared with the ability to kill human cell line A549 in vitro. On average, there was no significant difference between levels of animal and human cytotoxicity, while human isolates produced higher amounts of pyocyanin, hemolysins and showed increased swimming ability. Non-parametric statistical analysis identified the highest positive correlation between hemolysis and the swarming ability. For the first time an ensemble machine learning approach used on the in vitro virulence data determined the highest relative predictive importance of the submerged biofilm formation for the cytotoxicity, as an indicator of the infection ability. The findings from the in vitro study were validated in vivo using zebrafish (Danio rerio) embryos. This study highlighted no major differences between P. aeruginosa species isolated from animal and human infections and the importance of pyocyanin production in cytotoxicity and infection ability

Silver(I) complexes with different pyridine-4,5-dicarboxylate ligands as efficient agents for the control of cow mastitis associated pathogens

Infections of the cow udder leading to mastitis and lower milk quality are one of the biggest problems in the dairy industry worldwide. Unfortunately, therapeutic options for the treatment of cow mastitis are limited as a consequence of the development of pathogens that are resistant to conventionally used antibiotics. In the search for agents that will be active against cow mastitis associated pathogens, in the present study, five new silver(I) complexes with different chelating pyridine-4,5-dicarboxylate types of ligands, [Ag(NO3)(py-2py)](n) (1), [Ag(NO3)(py-2metz)](n) (2), [Ag(CH3CN)(py-2py)]BF4 (3), [Ag(py-2tz)(2)]BF4 (4) and [Ag(py-2metz)(2)]BF4 (5), py-2py is dimethyl 2,2'-bipyridine-4,5-dicarboxylate, py-2metz is dimethyl 2-(4-methylthiazol-2-yl)pyridine-4,5-dicarboxylate and py-2tz is dimethyl 2-(thiazol-2-yl)pyridine-4,5-dicarboxylate, were synthesized, structurally characterized and assessed for in vitro antimicrobial activity using both standard bioassay and clinical isolates from a contaminated milk sample obtained from a cow with mastitis. These complexes showed remarkable activity against the standard panel of microorganisms and a selection of clinical isolates from the milk of the cow diagnosed with mastitis. With the aim of determining the therapeutic potential of silver(I) complexes, their toxicity in vivo against the model organism, Caenorhabditis elegans (C. elegans), was investigated. The complexes that had the best therapeutic profile, 2 and 5, induced bacterial membrane depolarization and the production of reactive oxygen species (ROS) in Candida albicans cells and inhibited the hyphae as well as the biofilm formation. Taken together, the presented data suggest that the silver(I) complexes with pyridine ligands could be considered for the treatment of microbial pathogens, which are causative agents of cow mastitis