Progress towards the colonization of Cnephia mutata (Diptera: Simuliidae).

Cnephia mutata was successfully induced to complete two entire generations in the laboratory. Owing to its triploid condition, this simuliid is parthenogenetic and mature eggs may be dissected from the ovaries, thus eliminating both mating and oviposition. C. mutata in Newfoundland is also autogenous, making blood-feeding unnecessary. Progress towards colonization of this species is reviewed.     

Modification of rat operant behavior by ozone exposure

Ozone exposure may induce extrapulmonary consequences, such as reductions in the spontaneous activity of rodents, or complaints in humans of lethargy, headache, chest discomfort, and other subjective symptoms. Further evidence of behavioral disruption was provided by this experiment. Twelve rats were trained to perform a bar-pressing response maintained by food reward. Food pellets were delivered according to a fixed interval 5-min reinforcement schedule. Exposures encompassed a range of concentrations from 0.1 to 2.0 ppm. A single exposure lasted 6 hr, and successive exposures were separated by at least 6 days. Compared to performance under control conditions (ambient air), response rates fell linearly from 0.1 to 1.4 ppm. During individual 6-hr exposures, the rates declined from the beginning to the end of the session. These results, given the sedentary nature of the task, reflect reduced inclination rather than impaired physiological capacity to respond.     

Comparative evaluation of DNA damage by genotoxicants in primary rat cells applying the comet assay

Various compounds known to cause DNA damage (hydrogen peroxide, visible light-excited methylene blue, N-nitrosomorpholine and benzo[a]pyrene) were tested with different primary rat cells (lymphocytes, testicular cells, type II pneumocytes and hepatocytes) to determine the range of induced DNA damage applying the comet assay. A dose-dependent increase of DNA breaks was observed after treatment with hydrogen peroxide in all cell types studied. The most prominent effect was observed in lymphocytes, whereas only a slight increase of DNA breaks was observed in hepatocytes. Visible light-excited methylene blue caused significant oxidative DNA damage, which did not significantly differ between the cell types used with the exception of hepatocytes, for which a lower level of DNA damage was observed. N-Nitrosomorpholine and benzo[a]pyrene induced a moderate but significant increase of DNA strand breaks in pneumocytes and hepatocytes while in lymphocytes no effect was observed. Our results clearly demonstrate that due to their differential function which is also expressed by the level of drug metabolizing and/or antioxidant enzymes, freshly isolated rat cells (lymphocytes, testicular cells, type II pneumocytes and hepatocytes) respond differently to the exposure to genotoxic agents as detected by comet assay.     

Activation of autophagy by inflammatory signals limits IL-1β production by targeting ubiquitinated inflammasomes for destruction

Autophagosomes delivers cytoplasmic constituents to lysosomes for degradation, whereas inflammasomes are molecular platforms activated by infection or stress that regulate the activity of caspase-1 and the maturation of interleukin 1β (IL-1β) and IL-18. Here we show that the induction of AIM2 or NLRP3 inflammasomes in macrophages triggered activation of the G protein RalB and autophagosome formation. The induction of autophagy did not depend on the adaptor ASC or capase-1 but was dependent on the presence of the inflammasome sensor. Blocking autophagy potentiated inflammasome activity, whereas stimulating autophagy limited it. Assembled inflammasomes underwent ubiquitination and recruited the autophagic adaptor p62, which assisted their delivery to autophagosomes. Our data indicate that autophagy accompanies inflammasome activation to temper inflammation by eliminating active inflammasomes.     

Allergic sensitization enhances anion current responsiveness of murine trachea to PAR-2 activation

Protease-activated receptor 2 (PAR-2) is a G protein-coupled receptor possibly involved in the pathogenesis of asthma. PAR-2 also modulates ion transport in cultured epithelial cells, but these effects in native airways are controversial. The influence of allergic inflammation on PAR-2-induced changes in ion transport has received little attention. Here, we studied immediate changes in transepithelial short circuit current (I _sc) induced by PAR-2 activation in the tracheas of naive and allergic mice. Activation of PAR-2 with an apically added activation peptide (AP) induced a small increase in I _sc, while a much larger increase was observed following basolateral AP addition. In ovalbumin-sensitized and -challenged animals used as a model of allergic airway inflammation, the effect of basolateral AP addition was enhanced. Responses to basolateral AP in both naive and allergic mice were not decreased by blocking sodium absorption with amiloride or CFTR function with CFTR_inh172 but were reduced by the cyclooxygenase inhibitor indomethacin and largely blocked (>80%) by niflumic acid, a calcium-activated chloride channels’ (CaCC) blocker. Allergic mice also showed an enhanced response to ATP and thapsigargin. There was no change in mRNA expression of Par-2 or of the chloride channels Ano1 (Tmem16a) and Bestrophin 2 in tracheas from allergic mice, while mRNA levels of Bestrophin 1 were increased. In conclusion, basolateral PAR-2 activation in the mouse airways led to increased anion secretion through apical CaCC, which was more pronounced in allergic animals. This could be a protective mechanism aimed at clearing allergens and defending against mucus plugging.     

Mortality of therapeutic fish Garra rufa caused by Aeromonas sobria

Objective

To investigate a case of mass mortality of Garra rufa (G. rufa) from a fish hatchery farm in Slovakia.

Methods

Causative bacterial agent was swabbing out of affected fish skin area and subsequently identified using commercial test system. Antibiotic susceptibility was determined by the disk diffusion method.

Results

Infected G. rufa was characterized by abnormal swimming behaviour, bleeding of skin lesions and local haemorrhages. Despite of using recommended aquatic antibiotic treatment no improvement was achieved and Aeromonas sobria (A. sobria) was identified as a causative agent of fish mortality. Due to massive fish mortality, antibiotic susceptibility of pure isolated culture of A. sobria was evaluated employing eight antibiotics against human infections. A. sobria was resistant only against one antibiotic, namely ampicilin.

Conclusions

These results indicate that A. sobria can act as a primary pathogen of G. rufa and may be a potential risk factor for immunodeficient or immunoincompetent patients during the ichthyotherapy.