Frozen mitochondria as rapid water quality bioassay

A rapid and relatively low cost bioassay, usable in routine screening water test has been developed modifying the beef heart mitochondria test. In our experiments, mitochondria (FM22) were frozen at 22 °C, instead of 80 °C (FM80), and their applicability and sensitivity was verified. The oxygen consumption was measured by a Clark elec- trode that was interfaced to a PC to collect test analysis data. Blank tests were carried out to verify the oxygen con- sumption linear fitting. Toxicity tests were performed using pure organic and inorganic compounds, such to verify the FM22 sensitivity. A piecewise regression, through an Excelâ Macro, identified the break-point in the oxygen con- sumption and calculated the toxicity. The IC50s of the tested compounds were calculated and ranged from 0.123 to 0.173 mg/l for heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) and from 0.572 to 10.545 mg/l for organics (benzene, DMSO, DDE, endrin, dichloromethane, chlorobenzene, 1,2-dichlorobenzene and 1,3-dichlorobenzene). Water effluent samples were then tested. The FM22 gave different toxic reactions to them. Water samples were characterised for heavy metals. The FM22 bioassay had a higher sensitivity than the FM80 and a high reproducibility in the toxicity test with pure compounds. The FM22 test was a good predictor of toxicity for water samples; the bioassay is easy, low cost and rapid, then usable for routine tests

A case history of low frequency air-borne sound produced by a weir in the river Reno

Marzabotto is a small village in the north of Italy, near the city of Bologna. The town lies at the bottom of a broad valley where the river Reno flows. In 1985 strange vibrations of glass windows and doors started to disturb the rest and sleep of the population. Local newspapers wrote about the awakening of the ghosts of ancient Etruscans, a population that lived in this area in olden times. In order to discover the source of such vibrations, the authorities of the village first called researchers of the National Institute of Geophysics who made measurements of vibration in different parts of the village and identified the waterfall of a weir, recently built to control the flow of the river Reno, as the source of the phenomena. The spectrum of the vibrations was characterized by a frequency of 8 Hz. The presence of such at distances of about 4 - respect to the valley floor, of the phenomena could be vibrations 5 Km and brought up by air as far in the well away from the weir, raised positions with idea that transmission as by ground. Local authorities decided to start new investigations and entrusted the work to the Institute of Technical Physics and the Institute of Hydraulics of the University of Bologna. It was decided to begin a campaign of systematic measurements of noise and vibration in order to understand the origin of the phenomena

Site-directed spin labeling of the mitochondrial membrane. Synthesis and utilization of the adenosine triphosphatase inhibitor (N-(2, 2, 6, 6-tetramethyl-piperidyl-1-oxyl)-N'-(cyclohexyl)-carbodiimide).

Abstract NCCD (N-(2,2,6,6-tetramethyl-piperidyl-1-oxyl)-N'-(cyclohexyl)carbodiimide) is a spin label inhibitor of ATPase of mitochondrial membrane fragments. Upon binding (∼0.5 nmole per mg of protein) its electron paramagnetic resonance spectrum becomes highly immobilized (τc = 2.10-8 s). The bound but not the free label is reduced by succinate, indicating that electrons can be transferred from the respiratory chain to the ATPase system. The Mn++ATP complex decreases the paramagnetic signal of NCCD bound to membrane fragments about 30%. Such an interaction can be the consequence of the vicinity of the binding sites of the two species

Trialkyllead compounds induce the opening of the MPT pore in rat liver mitochondria

The interactions of the tributyl, triethyl and trimethyllead compounds with energized mitochondria have been investigated in this paper. It has been shown that the (alkyl)3Pb–Cl compounds induce swelling in mitochondria suspended in a sucrose medium. The phe- nomenon is more marked the higher the lipophilicity and occurs in the following order: (Bu)3Pb > (Et)3Pb > (Me)3Pb. As swelling is inhibited by cyclosporine, this suggests that the swelling is due to the opening of a trans-membrane pore (MTP pore) in the mitochondria. As this pore can be responsible for the inhibition of the ATP synthesis, and, consequently for cell death, the opening of the pore could be one of the reasons for the toxicity of the (alkyl)3Pb–X compounds

Determination of Chlorinated organic compounds in aqueous matrices

Thirteen pure volatile, semi-volatile and non-volatile chlorinated organic compounds of molecular weights ranging from trichloroethylene (MW = 131.39 g mole -¹) to hexachlorobenzene (MW = 284.78 g mole-¹) were determined in aqueous matrices by GC-ECD. After 10% salt addition, different extraction tests were performed using fibres whose adsorbing phase was based on microsphere carbon particles characterized by a constant size. Five experimental parameters were optimized: extraction temperature and time, position of the fibre in the GC injector port, desorption temperature and time. The optimized analytical protocol was employed to determine the efficiency of a real activated carbon adsorption plant to remove organic chlorinated pollutants from an industrial wastewater at ng l-¹ levels

An in vitro study on the toxic effects of nonylphenols (NP) in mitochondria

This paper is focused on alkylphenols, compounds which are formed by the biodegradation of polyethoxilatedalkylphenols detergents. Our experiments show that alkylphenols act not only as detergents, butalsoasuncouplersoftheoxidativephosphorylation. Thiseff~ot,canbeobservedatverylowdoses,thus suggesting that the preferential target ofnonylphenols in living organisms are mitochondria

Methylmercury induces the opening of the permeability transition pore in rat liver mithocondria.

Interactions of methylmercury (CH3HgCl) with non-energized mitochondria from rat liver (non-respiring mitochondria) have been investigated in this paper. It has been shown that CH3HgCl induces swelling in mitochondria suspended in a sucrose medium. Swelling has also been induced by detergent compounds and by phenylarsine, a chemical compound which induces opening of the permeant transition pore (MTP). Opening of the MTP is inhibited by means of cyclosporine A. Results indicate that the swelling induced by CH3HgCl, as in the case of phenylarsine, is inhibited by cyclosporine A and Mg , while swelling induced by detergent compounds is not cyclosporine sensitive. This comparison suggests that CH3HgCl induces opening of a permeability transition pore (MTP). Since the opening of an MTP induces cell death, this interaction with MTP could be one of the causes of toxicity of CH3HgCl

Interactions of melatonin with mammalian mitochondria. Reducer of energy capacity and amplifier of permeability transition.

Melatonin, a metabolic product of the amino acid tryptophan, induces a dose-dependent energy drop correlated with a decrease in the oxidative phosphorylation process in isolated rat liver mitochondria. This effect involves a gradual decrease in the respiratory control index and significant alterations in the state 4/state 3 transition of membrane potential (ΔΨ). Melatonin, alone, does not affect the insulating properties of the inner membrane but, in the presence of supraphysiological Ca2+, induces a ΔΨ drop and colloid-osmotic mitochondrial swelling. These events are sensitive to cyclosporin A and the inhibitors of Ca2+ transport, indicative of the induction or amplification of the mitochondrial permeability transition. This phenomenon is triggered by oxidative stress induced by melatonin and Ca2+, with the generation of hydrogen peroxide and the consequent oxidation of sulfydryl groups, glutathione and pyridine nucleotides. In addition, melatonin, again in the presence of Ca2+, can also induce substantial release of cytochrome C and AIF (apoptosis-inducing factor), thus revealing its potential as a pro-apoptotic agent