scholarly journals Toxin concentration in Nodularia spumigena is modulated by mesozooplankton grazers

2009 ◽  
Vol 31 (10) ◽  
pp. 1235-1247 ◽  
Author(s):  
E. Gorokhova ◽  
J. Engstrom-Ost
1979 ◽  
Author(s):  
T Harada ◽  
M Ohki ◽  
M Niwa ◽  
S Iwanaga

Limulus hemocyte lysate contains a proclotting enzyme, which is transformed to the active clotting enzyme in the presence of gram-negative bacterial endotoxins. The clotting enzyme coagulates a clottable protein, named coagulogen, contained also in the lysate. This gelation reaction of the lysate, named Limulus test, has been widely employed as a simple and very sensitive assay method for endotoxins. We developed a new fluorogenic substrate, Boc-Leu-Gly-Arg-4-methylcoumarin amide, for Limulus clotting enzyme and established an enzymatic assay method for endotoxins, using the substrate. Because the endotoxin mediates the activation of proclotting enzyme in the lysate, the measurement of amidase activity could be applicable for quantitation of the endotoxins. In fact, the amidase activity determined fluorometrically increased by increasing concentration of E. coli 0111: B4 endotoxin added to the lysate, and a linear relationship between the toxin concentration and the activity was observed in the range of 5X10-6to 5xl0-2 µg endotoxin. The method was a fifty times more sensitive than that of the Limulus test and was very reproducible. However, the method was not directly applicable for the assay of endotoxins in circulating blood, as the amidase activity was strongly inhibited by antithrombin III and α2-plasmin inhibitor. Thus, some pretreatment with heat or chloroform on plasma samples before the assay was required.


2003 ◽  
Author(s):  
Charles Thomas Parker ◽  
Dorothea Taylor ◽  
George M Garrity
Keyword(s):  

2003 ◽  
Author(s):  
Charles Thomas Parker ◽  
Dorothea Taylor ◽  
George M Garrity
Keyword(s):  

1996 ◽  
Vol 24 (4) ◽  
pp. 533-540 ◽  
Author(s):  
Paola Bonsi ◽  
Maura Palmery ◽  
Gabriella Augusti-Tocco

Aflatoxin B1 (AFB1), a metabolite produced by Aspergillus flavus and Aspergillus parasiticus, is mainly known for its strong hepatotoxic and hepatocarcinogenic actions. Acute and reversible effects due to exposure to aflatoxin and the presence of aflatoxins in various human tissues and organs have also been reported. In particular, aflatoxin M1 (a metabolite of AFB1) has been identified in human brain tissue, and a syndrome characterised by encephalopathy has been observed in humans poisoned by AFB1. As a first approach to the study of the neurotoxicity of AFB1, we used the human neuronal cell lines, SKNMC and SKNSH. The data reported show clearly that AFB1 is capable of interacting directly with neuronal cells and causing a decrease in cell number following the addition of toxin to the culture. Decrease in cell survival is dependent on the toxin concentration, on time of exposure, and on cell density. The cytotoxic response of these cells has been compared to the effects of AFB1 on hepatoma cells and spinal cord motor neurons. Postmitotic neurons are also susceptible to AFB1 toxicity, although to a lower extent than proliferating cells. A non-proliferating state thus appears to lower, but not destroy, neuron sensitivity to the toxin.


Marine Drugs ◽  
2012 ◽  
Vol 11 (12) ◽  
pp. 1-19 ◽  
Author(s):  
Hanna Mazur-Marzec ◽  
Monika Kaczkowska ◽  
Agata Blaszczyk ◽  
Reyhan Akcaalan ◽  
Lisa Spoof ◽  
...  

2014 ◽  
Vol 19 (1) ◽  
pp. 27
Author(s):  
Haryoto Kusnoputranto ◽  
Setyo S Moersidik ◽  
Djarot S Wisnubroto ◽  
Murdahayu Makmur

Ledakan mikroalga sering dilaporkan terjadi di Teluk Jakarta, dimana di lokasi tersebut juga terdapat kegiatan budidaya kerang hijau (Perna viridis). Terkait dengan hal tersebut maka dilakukan studi akumulasi dan depurasi toksin PSP (Paralytic Shellfish Poisoning) pada kerang hijau. Studi akumulasi dilakukan di bagan kerang hijau perairan Cilincing Jakarta Utara, dengan memisahkan kerang hijau yang berukuran sama dan ditempatkan kembali ke bagan. Sampling dilakukan setiap minggu selama 2 bulan dan diukur juga kelimpahan fitoplankton, pH, suhu dan salinitas perairan. Depurasi dilakukan di Unit Depurasi Kekerangan KKP Panimbang Banten, yang dilakukan selama 24 jam. Pencuplikan  sampel dilakukan setiap jam pada 4 jam pertama dan setiap 2 dan 3 jam pada waktu berikutnya. Penentuan konsentrasi toksin PSP dilakukan dengan menggunakan HPLC detektor fluoresensi. Prosedur preparasi, ekstraksi dan pengukuran konsentrasi toksin mengikuti Manual AOAC Official Method 2005.06 untuk toksin PSP dalam kekerangan. Akumulasi toksin PSP oleh kerang hijau di perairan Cilincing pada bulan Januari–Pebruari 2011 berkisar antara 4,11–11,96 µg STX eq. per 100 g dan tidak mempunyai korelasi dengan kelimpahan Dinoflagelata di perairan. Hal ini disebabkan uji akumulasi tidak dilakukan pada saat blooming mikroalga. Uji depurasi selama 24 jam mengeliminasi toksin PSP sebesar 60%, sehingga bisa diajukan sebagai sistem pemutus rantai toksin dari mikroalga ke manusia. Kata kunci: akumulasi, depurasi, PSP toksin, kerang hijau, Cilincing Microalgae blooms have been frequently reported in the Jakarta Bay, which is also the location of green mussel (Perna viridis) aquaculture. Accumulation and depuration of Paralytic Shellfish Poisoning (PSP) toxin in the green mussels were investigated in the field, where the toxin accumulation studies conducted in the mussel farming at Cilincing, North Jakarta. Accumulation test carried out by placing back the selected green mussel (equal size) into the mussel farming. Every week for 2 months, the green mussel were collected from mussel farming and transported to the laboratory. The fitoplankton abundance also was checked including pH, Suhue and salinitiy paramaters. Toxin depuration was conducted at Clams Sanitation Unit at Panimbang Banten. The depuration studies were conducted for 24 hours with sampling every hour in the first 4 hours and every 3 and 2 hours until the 24th hour. Preparation, extraction and toxin concentration measurements performed by following the Manual AOAC Official Method 2005.06 for PSP toxin in oyster. This research concluded that the accumulation of PSP toxin by green mussel, Perna viridis in the mussel farming at Cilincing, North Jakarta in ranged between 4,11–11,96 µg STX eq. per 100 g during January–February 2011. No correlation between PSP toxin concentration in the green mussel, Perna viridis with abundance of the PSP toxin sources phytoplankton, because the study wasnt done when microalgae blooming. The depuration processes was eliminate 60% the PSP toxins for 24 hours depuration processing. It can be proposes as a banded system the PSP toxin from algae to human being. Keywords: accumulation, depuration, PSP toxin, green mussel, Cilincing


1985 ◽  
Vol 86 (5) ◽  
pp. 739-762 ◽  
Author(s):  
G K Wang ◽  
G Strichartz

The effects of a neurotoxin, purified from the venom of the scorpion Leiurus quinquestriatus, on the ionic currents of toad single myelinated fibers were studied under voltage-clamp conditions. Unlike previous investigations using crude scorpion venom, purified Leiurus toxin II alpha at high concentrations (200-400 nM) did not affect the K currents, nor did it reduce the peak Na current in the early stages of treatment. The activation of the Na channel was unaffected by the toxin, the activation time course remained unchanged, and the peak Na current vs. voltage relationship was not altered. In contrast, Na channel inactivation was considerably slowed and became incomplete. As a result, a steady state Na current was maintained during prolonged depolarizations of several seconds. These steady state Na currents had a different voltage dependence from peak Na currents and appeared to result from the opening of previously inactivated Na channels. The opening kinetics of the steady state current were exponential and had rates approximately 100-fold slower than the normal activation processes described for transitions from the resting state to the open state. In addition, the dependence of the peak Na current on the potential of preceding conditioning pulses was also dramatically altered by toxin treatment; this parameter reached a minimal value near a membrane potential of -50 mV and then increased continuously to a "plateau" value at potentials greater than +50 mV. The amplitude of this plateau was dependent on toxin concentration, reaching a maximum value equal to approximately 50% of the peak current; voltage-dependent reversal of the toxin's action limits the amplitude of the plateauing effect. The measured plateau effect was half-maximum at a toxin concentration of 12 nM, a value quite similar to the concentration producing half of the maximum slowing of Na channel inactivation. The results of Hill plots for these actions suggest that one toxin molecule binds to one Na channel. Thus, the binding of a single toxin molecule probably both produces the steady state currents and slows the Na channel inactivation. We propose that Leiurus toxin inhibits the conversion of the open state to inactivated states in a voltage-dependent manner, and thereby permits a fraction of the total Na permeability to remain at membrane potentials where inactivation is normally complete.


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