Engineering siderophore production in Pseudomonas to improve asbestos weathering.

Iron plays a key role in microbial metabolism and bacteria have developed multiple siderophore-driven mechanisms due to its poor bioavailability for organisms in the environment. Iron-bearing minerals generally serve as a nutrient source to sustain bacterial growth after bioweathering. Siderophores are high-affinity ferric iron chelators, of which the biosynthesis is tightly regulated by the presence of iron.

A Review of Asbestos Bioweathering by Siderophore-Producing : A Potential Strategy of Bioremediation.

Asbestos, silicate minerals present in soil and used for building constructions for many years, are highly toxic due primarily to the presence of high concentrations of the transition metal iron. Microbial weathering of asbestos occurs through various alteration mechanisms. Siderophores, complex agents specialized in metal chelation, are common mechanisms described in mineral alteration.

Biodeterioration of asbestos cement by siderophore-producing Pseudomonas.

Since the ban on the use of asbestos due to its carcinogenic properties, the removal of asbestos cement, representing the major asbestos-containing waste, has proven to be a challenge in most industrial countries. Asbestos-containing products are mainly disposed of in landfills and have remained untreated. Bioremediation involving bacteria previously reported the ability of Pseudomonas aeruginosa to release iron from flocking asbestos waste through a siderophore-driven mechanism.

Efficiency of pyoverdines in iron removal from flocking asbestos waste: An innovative bacterial bioremediation strategy.

The use of asbestos-containing products has been banned in many countries since the beginning of the 80's due to its carcinogenic properties. However, asbestos is widely present in private and public buildings, resulting in the need to process a vast amount of asbestos-containing waste. Among the current technologies for the destruction of asbestos fibers, biodegradation by fungi, lichens, and, more recently, bacteria has been described.

Flocking asbestos waste, an iron and magnesium source for Pseudomonas.

Iron and magnesium are essential nutrients for most microorganisms. In the environment, the availability of iron is low relative to that of magnesium. Microorganisms have developed various iron acquisition systems, which have been well studied, whereas few studies have examined magnesium acquisition.

Iron removal from raw asbestos by siderophores-producing Pseudomonas.

Asbestos, mineral present in soil, are highly toxic due to the presence of iron. Microbes-mineral interactions occur naturally through various processes leading to their alteration. We examined the effect of siderophore-producing Pseudomonas with a particular focus on the role of pyoverdine and pyochelin on raw asbestos fibers such as amosite, crocidolite and chrysotile.

Community structure and functional genes in radionuclide contaminated soils in Chernobyl and Fukushima.

Chernobyl and Fukushima were subjected to radionuclide (RN) contamination that has led to environmental problems. In order to explore the ability of microorganisms to survive in these environments, we used a combined 16S rRNA and metagenomic approach to describe the prokaryotic community structure and metabolic potential over a gradient of RN concentrations (137Cs 1680-0.4 and 90Sr 209.

[Solitary fibrous tumor of the meninges: report of three cases].

The authors expose the clinical, radiological and histological presentation of three cases of solitary fibrous tumors of the meninges, initially thought to be meningiomas. Actually, these three cases show typical anatomoclinical features. The authors also mention the differential diagnosis, and recall the essential contribution of immunohistochemistry.

Treatment of experimental spinal cord injury with 3β-methoxy-pregnenolone.

The synthetic derivative of pregnenolone MAP4343 (3β-methoxy-pregnenolone) binds in vitro to microtubule-associated-protein 2 (MAP2), stimulates the polymerization of tubulin, enhances the extension of neurites and protects neurons against neurotoxic agents. Its efficacy was assessed in vivo with the most commonly used thoracic spinal cord compression/contusion models in rats. In the three models used, the post-traumatic subcutaneous injection of MAP4343 significantly improved the recovery of locomotor function after spinal cord injury, as shown by an earlier and more complete recovery compared to vehicle-treated rats.

Microtubule target for new antileishmanial drugs based on ethyl 3-haloacetamidobenzoates.

A new family of antimicrotubule drugs named (3-haloacetamidobenzoyl) ureas and ethyl 3-haloacetamidobenzoates were found to be cytotoxic to the Leishmania parasite protozoa. While the benzoylureas were shown to strongly inhibit in vitro mammalian brain microtubule assembly, the ethyl ester derivatives were characterized as very poor inhibitors of this process. Ethyl 3-chloroacetamidobenzoate, MF29, was found to be the most efficient drug on the promastigote stage of three Leishmania species (IC50: 0.

Microtubule-associated protein 2 (MAP2) is a neurosteroid receptor.

The neurosteroid pregnenolone (PREG) and its chemically synthesized analog 3beta-methoxypregnenolone (MePREG) bind to microtubule-associated protein 2 (MAP2) and stimulate the polymerization of microtubules. PREG, MePREG, and progesterone (PROG; the physiological immediate metabolite of PREG) significantly enhance neurite outgrowth of nerve growth factor-pretreated PC12 cells. However, PROG, although it binds to MAP2, does not increase the immunostaining of MAP2, contrary to PREG and MePREG.

MAPREG: toward a novel approach of neuroprotection and treatment of Alzheimer's disease.

MAPREG (microtubule-associated protein/neurosteroidal pregnenolone) is a start-up company that was created in October 2000. Its acronym recalls the basic discovery (Murakami et al., 2000) from which drug(s) will hopefully be developed that are useful for neuroprotection and repair in conditions such as post-traumatic and postischemic lesions, as well as defects proper to normal aging and neurodegenerative diseases, that is, principally Alzheimer's disease.

Occurrence of nuclear beta(II)-tubulin in cultured cells.

Microtubules are cylindrical organelles that play critical roles in cell division. Their subunit protein, tubulin, is a target for various antitumor drugs. Tubulin exists as various forms, known as isotypes.