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Biomedical subjects

M Blaghen

Publications and source records attributed to M Blaghen.

9 recordsLinked to original sources
PubMed2001

Volatilization of mercury by immobilized bacteria (Klebsiella pneumoniae) in different support by using fluidized bed bioreactor.

Klebsiella pneumoniae, a mercury-resistant bacterial strain able to reduce ionic mercury to metallic mercury, was isolated from wastewater of Casablanca. This strain exhibits high minimal inhibition concentrations for heavy metals such as mercury 2400 microM, lead 8000 microM, silver 2400 microM, and cadmium 1000 microM. This bacterium was immobilized in alginate, polyacrylamide, vermiculite, and cooper beech and was used for removing mercury from a synthetic water polluted by mercury by using a fluidized bead bioreactor. Immobilized bacterial cells of Klebsiella pneumoniae could effectively volatilize mercury and detoxify mercury compounds. Moreover, the efficiency of mercury volatilization was much greater than with the native cells. The highest cleanup and volatilization rates were obtained when Klebsiella pneumoniae was entrapped in alginate beads, with a cleanup rate of 100% and a volatilization rate of 89%. Immobilized cells in alginate continuously volatilized mercury even after 10 days without loss of activity.

Acrylic Resins↗
PubMed2001

Alkamides from Artemisia dracunculus.

From the aerial parts of Artemisia dracunculus, one known alkamide, pellitorine, two new alkamides neopellitorine A and neopellitorine B, and one known coumarin herniarine were isolated. Structures were elucidated by means of UV, IR, MS, 1H and 13C NMR. These compounds showed insecticidal activity against Sitophilus oryzae and Rhyzopertha dominica at 200 microg/ml concentrations.

Amides↗
PubMed2001

Study of paralytic shellfish poisoning toxin profile in shellfish from the Mediterranean shore of Morocco.

Since 1992, a monitoring program for bivalve molluscs contaminated by algal toxins was established at different stations along the Mediterranean Moroccan shores. The monitored stations were tested every 2 weeks. The presence of toxicity was determined using the mouse bioassay method. Toxin profile was carried out by HPLC/FD in selected contaminated tissues. According to the outcomes of this surveillance from 1994 to 1999, reliable information on toxicity of shellfish was obtained. They indicate that PSP is a recurrent toxicity in molluscs along the Mediterranean shore of Morocco. It has been noted a difference of PSP accumulation among individual shellfish. The cockle (Achanthocardia tuberculatum) presents toxicity throughout the year, while other specimens from the same area such as clam (Callista chione), warty venus (Venus gallina) and marine beans (Donax trunculus) accumulate it seasonally from January to April, after which they depurate the toxin. Moreover, the study of toxin profiles among individual shellfish was undertaken. It was found that shellfish presented a complex profile pointing to contamination by Gymnodinium catenatum.

Animals↗
PubMed2000

Waste water bacterial isolates resistant to heavy metals and antibiotics.

Sewage water of Casablanca, an industrial city in Morocco, was studied for microorganisms resistant to heavy metals. Isolates were purified and collected on agar slants to be screened for resistance to heavy metals, including mercury in vitro. The strains that showed high resistance to heavy metals were also studied for their resistance to antibiotics and aromatic hydrocarbons. Results indicated that the strains most resistant to all tested products belonged to Ps. fluorescens, Ps. aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus sp. These strains exhibit high minimal inhibitory concentrations for heavy metals such as cadmium (2 mm) or mercury (1.2 mm). Growth of Ps. fluorescens and Klebsiella pneumoniae in the presence of heavy metals was also determined, and the growth curves indicated that mercury, copper, and zinc present a slight inhibitory action, while cadmium and silver could have a potent inhibitory action on growth compared with the controls. These studies also investigated growth in media containing aromatic compounds as the sole source of carbon. The results demonstrate that these strains could be good candidates for remediation of some heavy metals and aromatic compounds in heavily polluted sites.

Anti-Bacterial Agents↗
PubMed1999

Complexation and ionophoric properties of taxol and colchicine: complex formation and transport of sodium, potassium, magnesium and calcium ions across a liquid membrane.

We report the activities of taxol (an anticancer drug) and colchicine, which are inhibitors of microtubule organization, on the complexation and transport of Na+, K+, Mg2+ and Ca2+ ions across a liquid membrane, using a spectrophotometric procedure. Taxol, a diterpenoid compound, that has been demonstrated to possess a potent antitumour activity, is shown to extract Na+, K+, Mg2+ and Ca2+ ions from the aqueous solution to the organic phase with preference for Ca2+ ions. A kinetic study of the transport and complexation of Na+, K+, Mg2+ and Ca2+ ions through a liquid membrane revealed that the K+ ion is more rapidly transported and the Ca2+ ion is more rapidly complexed than other ions. However, colchicine, another alkaloid compound, extracted and transported only the divalent ions tested, Mg2+ and Ca2+. In both complexation and transport, the flux of the ions increases with the concentration of taxol or colchicine. Complexation and ionophoric properties of taxol and colchicine sheds new lights on therapeutic properties of these drugs. The treatment of disease states by the administration of these drugs to alter membrane permeability will prove to be a valuable therapeutic concept.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Okadaic acid and its interaction with sodium, potassium, magnesium and calcium ions: complex formation and transport across a liquid membrane.

Okadaic acid, a macrocyclic polyether compound, was shown to mediate the transfer of Na+, K+, Mg2+ and Ca2+ ions from aqueous solution to an organic phase, with a preference for Na+ ions. A kinetic study of the transport of these ions across a liquid membrane showed that the Na+ ion was more rapidly transported than the other ions and that the Na+ ion flux was dependent on the okadaic acid concentration.

Biological Transport↗
PubMed1993

Purification and properties of mercuric reductase from Yersinia enterocolitica 138A14.

A mercuric ion-reducing flavoprotein was purified from Yersinia enterocolitica 138A14 using dye matrix affinity chromatography. The purified enzyme had a characteristic absorption spectrum similar to those of flavin compounds, and FAD was detected as a part of the purified enzyme by thin-layer chromatography. Freshly purified preparations of the enzyme showed a single band on SDS polyacrylamide gel electrophoresis with a molecular weight of 70,000. The isolated enzyme had a molecular weight of about 200,000 as determined by gel filtration and disc gel electrophoresis. These results suggest an apparently trimeric structure of the enzyme. Dithiothreitol treatment disrupted the trimer into a dimeric structure of 140,000. Along with ageing, as well as limited proteolytic digestion, the enzyme evolved to give a dimeric molecule of 105,000 composed of two identical subunits of 52,000. The combination of the purified enzyme with HgCl2, or unexpectedly with merthiolate, oxidised the NADPH, which was followed spectrophotometrically. The Km for HgCl2 was dependent on the concentration of exogenous thiol compounds. A comparison of physical properties as well as kinetic characteristics indicated that the enzyme from Y. enterocolitica 138A14 is similar to mercuric reductases isolated from other mercury-resistant bacteria.

Chromatography, Agarose↗
PubMed1992

Essential arginines in mercuric reductase isolated from Yersinia enterocolitica 138A14.

The mercuric reductase from Yersinia enterocolitica 138A14 was inactivated by the arginine modifying reagents 2,3-butanedione and phenylglyoxal. The inactivation by 2,3-butanedione exhibited second order kinetics with rate constant of 32 min-1 M-1. In the case of phenylglyoxal, biphasic kinetics were observed. The oxidized coenzyme (NADP+) prevented inactivation of the enzyme by the alpha-dicarbonyl reagents, whereas the reduced coenzyme (NADPH) enhanced the inactivation rate. The loss of enzyme activity was related to the incorporation of [2-14C] phenylglyoxal; when two arginines per subunit were modified the enzyme was completely inactivated.

Arginine↗