TY - JOUR AU - Kiss, Tibor AU - Vehovszky, Ágnes AU - Hiripi, László AU - Kovács, Attila AU - Vörös, Lajos TI - Membrane effects of toxins isolated from a cyanobacterium, Cylindrospermopsis raciborskii, on identified molluscan neurones JF - COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY AND PHARMACOLOGY J2 - COMP BIOCHEM PHYS C VL - 131 PY - 2002 IS - 2 SP - 167 EP - 176 PG - 10 SN - 1532-0456 DO - 10.1016/S1532-0456(01)00290-3 UR - https://m2.mtmt.hu/api/publication/1167371 ID - 1167371 AB - The effect of anatoxin (ANTX), the crude extract (AlgTX) and purified fraction (FI) isolated from cyanobacterium C. raciborskii was studied on the neurones of two snail species. ANTX and AlgTX exerted excitatory, inhibitory and biphasic effects on the spontaneous activity of identified neurones. Both ANTX and AlgTX elicited an inward current. which could be decreased by curare or amiloride. On the contrary, F1 had no direct effect on the spontaneous activity; it was not able to induce conductance changes of the neuronal membrane, but it did antagonise the acetylcholine (ACh)induced inward current. We concluded that ANTX affects the neuronal membrane of neurones acting on ACh receptors. The AlgTX had similar effects, and therefore the extract of C. raciborskii may contain an ANUX-like component. The purified fraction prolonged and decreased the ACh-elicited response, but had no direct membrane effect. We suggest, therefore, that both AlgTX and the purified fraction 171 interact with the ACh receptor, but they have different binding sites on the neuronal ACh receptor-ion channel complex. The possible neurotoxic effects of the C raciborskii extract and 171 are demonstrated for the first time-, the molecular mechanism of their action, however, remains to be elucidated. LA - English DB - MTMT ER - TY - JOUR AU - Hiripi, László AU - Nagy, L AU - Kalmár, Tibor AU - Kovács, Attila AU - Vörös, Lajos TI - Insect (Locusta migratoria migratorioides) test monitoring the toxicity of Cyanobacteria JF - NEUROTOXICOLOGY J2 - NEUROTOXICOLOGY VL - 19 PY - 1998 IS - 4-5 SP - 605 EP - 608 PG - 4 SN - 0161-813X UR - https://m2.mtmt.hu/api/publication/1138620 ID - 1138620 AB - An insect test was developed to investigate the toxicity of cyanobacteria. The African locust, Locusta migratoria migratorioides R.F. was used as a test animal instead of mouse. The cyanobacteria tested were Aphanizomenon flos-aque, Anabaena aphanizomenoides, Cylindrospermopsis raciborskii, Microcystis aeruginosa. The toxicity of authentic microcystin-LR was also tested. Cyanobacteria producing toxins killed the animals when the homogenized cell suspension was injected into the animals. The locust test proved to be more sensitive than the mouse test. The LD50 values of the different cyanobacteria for locusts and for mice, respectively were the following: 90 mu g/animal (60 mg/kg) and 8000 mu g/animal (320 mg/kg), for Aphanizomenon flos-aquae; 255 mu g/animal (170.2 mg/kg) and 3750 mu g/animal (150 mg/kg), for Anabaena aphanizomenoides; 195 mu g/animal (131.4 mg/kg) and 5750 mu g/animal (230 m/kg) for Cylindrospermopsis raciborskii; 22.5 mu g/animal (15 mg/kg) and 6000 mu g/animal (240 mg/kg), for Microcystis aeruginosa.. In locusts the LD50 value for authentic microcystin-LR was 0.2 mu g/animal (130 mg/kg). Since the weight of the mice is 15 to 20 times larger than that of the locusts, hence less toxic cells are needed to kill the locusts. The locust test is cheaper than the mouse test, large number of animals can be used in the experiments and the LD50 values can be estimated more precisely. The toxicity of C. raciborskii was significantly lower when the lyophilized cells were extracted in methanol (LD50 = 767 mg/kg), instead of NaCl solution (LD50 = 131.4 mg/kg). LA - English DB - MTMT ER -