Ostreolysin A (OlyA) and pleurotolysin B (PlyB), isolated from edible oyster mushrooms, form a cytolytic complex (OlyA/PlyB) in membrane cells that causes respiratory arrest. This study evaluated the mechanisms underlying cytotoxic OlyA/PlyB activity in neuroblastoma NG108-15 cells. Confocal microscopy with morphometric analysis revealed that OlyA/PlyB increased the 3-dimensional projected area of differentiated cells. Iso-osmotic replacement of NaCl by sucrose or Na-isethionate prevented the cellular swelling. This suggests that formation of cellular edema requires the presence of Na+ and/or Cl- in the extracellular space and may be related to an influx of Na+ and/or a shift in Cl-, which induce a marked influx of water that is ultimately responsible for cellular swelling. In addition, extracellular Ca2+ moderately contributed to the swelling because benzamil (10 µM), a 3Na+/Ca2+ exchange (NCX) inhibitor, and Ca2+-free medium partially prevented this response. Fluorometric measurements revealed that OlyA/PlyB, at approximately 15-fold higher concentrations, increased the intracellular Ca2+ activity [Ca2+]i. This increase was dependent on the presence of Na+ and Ca2+ in the external medium and was sensitive to benzamil. It is thus likely that a switch in the NCX mode, associated with the de novo formation of non-selective ion pores by OlyA/PlyB in cellular plasma membranes, plays an important role in this effect. Overall, OlyA/PlyB affects neuroblastoma cell morphology and Ca2+ homeostasis to influence the toxin-induced respiratory arrest.
COBISS.SI-ID: 3944570
The effects of Beauvericin (BEA) produced by the fungus Beauveria bassiana and Fusarium sp. on neuromuscular transmission and contractility were determined in an isolated neuromuscular mouse hemidiaphragm preparation. BEA (5 µM) significantly inhibits indirectly elicited twitch amplitude. At higher concentrations (7.5 and 10 µM), BEA produces a significant reduction of directly elicited, or complete block of indirectly evoked, muscle contraction. BEA also appears to be myotoxic, as indicated by a slowly developing muscle contracture. Development of neuromuscular blockade and contracture is concentration dependent. BEA acted by presynaptically depressing spontaneous acetylcholine release as indicated by the reduction in the frequency of spontaneous miniature endplate potentials (MEPPs), while the membrane potential of muscle fibers remained unchanged. At higher concentrations (7.5 and 10 µM), BEA progressively reduces or completely blocks MEPPs and EPPs amplitudes. Changes in MEPPs and EPPs are associated with substantial depolarization of muscle fibers when exposed to 7.5 and 10 µM of BEA. These results indicate that BEA has neurotoxic and myotoxic effects, which overlap in a narrow range of concentrations.
COBISS.SI-ID: 4093818
Kisspeptin, a regulator of reproductive function and puberty in mammals, is expressed in the rostral (anteroventral) periventricular nucleus (AVPV) and arcuate nucleus (Arc), and its expression is at least partially regulated by estradiol in rodents. The aim of the present study was to determine contributions of genetic factors and gonadal steroid hormones to the sexual differentiation of kisspeptin-immunoreactive (kisspeptin-ir) cell populations in the AVPV and Arc during postnatal development using agonadal steroidogenic factor 1 (SF-1) knockout (KO) mice. To examine the effects of gonadal hormones on pubertal development of kisspeptin neurons, SF-1 KO mice were treated with estradiol benzoate (EB) from postnatal day (P)25 to P36, and their brains were examined at P36. No sex differences were observed in the SF-1 KO mice during postnatal development and after treatment with EB – which failed to increase the number of kisspeptin-ir cells at P36 to the levels found in wild-type (WT) control females. This suggests that specific time periods of estradiol actions or other factors are needed for sexual differentiation of the pattern of immunoreactive kisspeptin in the AVPV. Kisspeptin immunoreactivity in the Arc was significantly higher in gonadally intact WT and SF-1 KO females than in male mice at P36 during puberty. Further, in WT and SF-1 KO females, but not in males, adult levels were reached at P36.
COBISS.SI-ID: 4009594
NNeurological examinations conducted over two weeks and quantitative histomorphometric and immunohistochemical analyses were used to evaluate the neurotoxic effect of 1.3 % liposomal bupivacaine after perineural and intraneural (extrafascicular) injection of the sciatic nerve in prospective randomized trial in pigs. Intraneural-extrafascicular injection of saline was used as a control. After harvesting the sciatic nerves, no changes in nerve fibre density or myelin width indicative of nerve injury were observed in any of the groups. Intraneural injections resulted in significantly longer sensory blockade than perineural without persistent motor or sensory deficit. Sciatic nerve block with liposomal bupivacaine in pigs did not result in histological evidence of nerve injury.
COBISS.SI-ID: 32164313
The aim of this study was to investigate the seasonal thermal effect on lipid metabolism, antioxidant activity and reproductive performance in dairy cows. Heat stressed dairy cows usually have reduced nutrient intake resulting in a higher degree of negative energy balance (NEB) contributing to lower fertility of dairy cows with a great economic impact in dairy industry.Healthy dairy heifers included in the study were divided in winter and summer group according to the ambient temperature at insemination. Metabolic parameters, PON1 activity and total antioxidative status (TAS) were monitored at the time of insemination (basal values) and from 1 week before until 8 weeks after calving. Number of services per conception and calving to conception (CC) interval were calculated from the farm recording data. Serum triglycerides, NEFA and BHB concentrations were significantly increased after calving in summer compared to winter indicating higher degree of NEB in cows during summer. PON1 activity was significantly decreased after calving in both summer and winter group. TAS concentration was significantly lower in summer than in winter; in winter TAS at calving significantly correlated with CC interval. A significantly higher number of services were needed for conception in summer compared to winter and CC interval was significantly longer in summer than in winter as well. Additionally, reproductive performance significantly correlated with the severity of NEB. The results indicated that heat stress has negative effect on energy metabolism, antioxidant status and reproductive performance in dairy cows.
COBISS.SI-ID: 3996794