A Molecule of the Viridomycin Family Originating from a -Related Strain Has the Ability to Solubilize Rock Phosphate and to Inhibit Microbial Growth.

Some soil-borne microorganisms are known to have the ability to solubilize insoluble rock phosphate and this process often involves the excretion of organic acids. In this issue, we describe the characterization of a novel solubilizing mechanism used by a strain related to isolated from Moroccan phosphate mines. This process involves the excretion of a compound belonging to the viridomycin family that was shown to play a major role in the rock phosphate bio weathering process.

Petroleum sludge bioremediation and its toxicity removal by landfill in gunder semi-arid conditions.

In this investigation, petroleum sludge landfilling was carried out in order to assess the biodegradation degree and the final product quality. The microbial analysis showed a good microorganism proliferation which reinforces the biodegradation process. The total mesophilic and thermophilic microflora evaluated symmetrically as they increased at the intermediate stage and decreased at the final.

Early events induced by the toxin deoxynivalenol lead to programmed cell death in Nicotiana tabacum cells.

Deoxynivalenol (DON) is a mycotoxin affecting animals and plants. This toxin synthesized by Fusarium culmorum and Fusarium graminearum is currently believed to play a decisive role in the fungal phytopathogenesis as a virulence factor. Using cultured cells of Nicotiana tabacum BY2, we showed that DON-induced programmed cell death (PCD) could require transcription and translation processes, in contrast to what was observed in animal cells.

Enzymatic synthesis of dithiolopyrrolone antibiotics using cell-free extract of Saccharothrix algeriensis NRRL B-24137 and biochemical characterization of two pyrrothine N-acyltransferases in this extract.

Saccharothrix algeriensis NRRL B-24137 produces naturally different dithiolopyrrolone derivatives. The enzymatic activity of pyrrothine N-acyltransferase was determined to be responsible for the transfer of an acyl group from acyl-CoA to pyrrothine core. This activity was also reported to be responsible for the diversity of the dithiolopyrrolone derivatives.

Actinopolyspora righensis sp. nov., a novel halophilic actinomycete isolated from Saharan soil in Algeria.

A novel halophilic actinomycete strain, H23(T), was isolated from a Saharan soil sample collected in Djamâa (Oued Righ region), El-Oued province, South Algeria. Strain H23(T) was identified as a member of the genus Actinopolyspora by a polyphasic approach. Phylogenetic analysis showed that strain H23(T) had 16S rRNA gene sequence similarities ranging from 97.

Actinopolyspora mzabensis sp. nov., a halophilic actinomycete isolated from an Algerian Saharan soil.

A halophilic actinomycete strain, designated H55(T), was isolated from Saharan soil sampled in the Mzab region (Ghardaïa, southern Algeria) and was characterized in a taxonomic study using a polyphasic approach. The cell wall was determined to contain meso-diaminopimelic acid and the characteristic whole-cell sugars were arabinose and galactose. The predominant menaquinones were found to be MK-10(H4) and MK-9(H4).

Saccharothrix saharensis sp. nov., an actinomycete isolated from Algerian Saharan soil.

The taxonomic position of a novel actinomycete, strain SA152(T), isolated from a sample of Algerian Saharan soil, was determined using a polyphasic taxonomic approach. The strain produced abundant aerial mycelium and fragmented substrate mycelium on most media tested. Chemotaxonomically and phylogenetically, the strain was related to the members of the genus Saccharothrix.

Actinopolyspora saharensis sp. nov., a novel halophilic actinomycete isolated from a Saharan soil of Algeria.

A novel halophilic actinomycete, strain H32(T), was isolated from a Saharan soil sample collected in El-Oued province, south Algeria. The isolate was characterized by means of polyphasic taxonomy. Optimal growth was determined to occur at 28-32 °C, pH 6.

Season's variation impact on Citrus aurantium leaves essential oil: chemical composition and biological activities.

Citrus aurantium leaves' essential oils (EOs) were evaluated for chemical composition and antioxidant and antibacterial activities. The vegetable material, taken 5 times during the year, has undergone the hydrodistillation to prepare EO. Chemical characterization by gas chromatography/mass spectrometry and GC/flame ionization detection allowed the identification of 46 compounds, and a notable quantitative and qualitative differences between the different Petitgrain samples according to the harvest time.

Chemical composition and in vitro evaluation of the antioxidant and antimicrobial activities of Eucalyptus gillii essential oil and extracts.

In this study, essential oil and various extracts (hexane, petroleum ether, acetone, ethanol, methanol and water) of Eucalyptus gilii were screened for their chemical composition, antimicrobial and antioxidant activities. The essential oil chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID), respectively. Thirty four compounds were identified, corresponding to 99.

Actinopolyspora algeriensis sp. nov., a novel halophilic actinomycete isolated from a Saharan soil.

A halophilic actinomycete strain designated H19(T), was isolated from a Saharan soil in the Bamendil region (Ouargla province, South Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the strain were consistent with those of members of the genus Actinopolyspora, and 16S rRNA gene sequence analysis confirmed that strain H19(T) was a novel species of the genus Actinopolyspora. DNA-DNA hybridization value between strain H19(T) and the nearest Actinopolyspora species, A.

Saccharothrix sp. PAL54, a new chloramphenicol-producing strain isolated from a Saharan soil.

An actinomycete strain designated PAL54, producing an antibacterial substance, was isolated from a Saharan soil in Ghardaïa, Algeria. Morphological and chemical studies indicated that this strain belonged to the genus Saccharothrix. Analysis of the 16S rDNA sequence showed a similarity level ranging between 96.

Saccharothrix hoggarensis sp. nov., an actinomycete isolated from Saharan soil.

An actinomycete, designated SA181(T), was isolated from Saharan soil in the Hoggar region (south Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the isolate were consistent with the genus Saccharothrix, and 16S rRNA gene sequence analysis confirmed that strain SA181(T) was a novel member of the genus Saccharothrix. DNA-DNA hybridization values between strain SA181(T) and its closest phylogenetic neighbours, the type strains of Saccharothrix longispora, Saccharothrix texasensis and Saccharothrix xinjiangensis, were clearly below the 70 % threshold.

Differentiation between Aspergillus flavus and Aspergillus parasiticus from pure culture and aflatoxin-contaminated grapes using PCR-RFLP analysis of aflR-aflJ intergenic spacer.

Aflatoxins (AFs) represent the most important single mycotoxin-related food safety problem in developed and developing countries as they have adverse effects on human and animal health. They are produced mainly by Aspergillus flavus and A. parasiticus.

Quantification of Fusarium graminearum and Fusarium culmorum by real-time PCR system and zearalenone assessment in maize.

Zearalenone (ZEA) is a mycotoxin produced by some species of Fusarium, especially by Fusarium graminearum and F. culmorum. ZEA induces hyperoestrogenic responses in mammals and can result in reproductive disorders in farm animals.

Isolation, taxonomy, and antagonistic properties of halophilic actinomycetes in Saharan soils of Algeria.

The diversity of a population of 52 halophilic actinomycetes was evaluated by a polyphasic approach, which showed the presence of members of the Actinopolyspora, Nocardiopsis, Saccharomonospora, Streptomonospora, and Saccharopolyspora genera. One strain was considered to be a new member of the last genus, and several other strains seemed to be new species. Furthermore, 50% of strains were active against a broad range of indicators and contained genes encoding polyketide synthetases and nonribosomal peptide synthetases.

Taxonomic study and partial characterization of antimicrobial compounds from a moderately halophilic strain of the genus Actinoalloteichus.

A moderately halophilic actinomycete strain designated AH97 was isolated from a saline Saharan soil, and selected for its antimicrobial activities against bacteria and fungi. The AH97 strain was identified by morphological, chemotaxonomic and phylogenetic analyses to the genus Actinoalloteichus. Analysis of the 16S rDNA sequence of strain AH97 showed a similarity level ranging between 95.

Purification and structure elucidation of three naturally bioactive molecules from the new terrestrial Streptomyces sp. TN17 strain.

Thirty litres of fermentation broth was extracted from the newly isolated Streptomyces sp. strain TN17 and various separation and purification steps led to the isolation of three pure bioactive compounds (1-3). Compound 1: cyclo (L-Leu-L-Arg), a diketopiperazine 'DKP' derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; and 3: cyclo 1-[2-(cyclopentanecarbonyl-3-phenyl-propionyl]-pyrrolidine-2-carboxylic acid (1-carbamoyl-propyl)-amide, a cyclic tetrapeptide derivative.

Eucalyptus oleosa essential oils: chemical composition and antimicrobial and antioxidant activities of the oils from different plant parts (stems, leaves, flowers and fruits).

Essential oils obtained by hydrodistillation from the different parts (stems, adult leaves, immature flowers and fruits) of Eucalyptus oleosa were screened for their antioxidant and antimicrobial properties and their chemical composition. According to GC-FID and GC-MS, the principal compound of the stem, immature flowers and the fruit oils was 1,8-cineole, representing 31.5%, 47.

New dithiolopyrrolone antibiotics induced by adding sorbic acid to the culture medium of Saccharothrix algeriensis NRRL B-24137.

Dithiolopyrrolone antibiotics, produced by several microorganisms, are known for their strong antimicrobial activities. This class of antibiotics generated new interest after the discovery of their anticancer and antitumor properties. In this study, four new antibiotics were purified from the fermentation broth of Saccharothrix algeriensis NRRL B-24137 and characterized as dithiolopyrrolone derivatives.

Essential oil of Thymus capitatus Hoff. et Link. from Matmata, Tunisia: gas chromatography-mass spectrometry analysis and antimicrobial and antioxidant activities.

Thymus capitatus Hoff. et Link. essential oil was constituted by thymol (89.

Aspergillus section Flavi and aflatoxins in Algerian wheat and derived products.

Wheat and its derivatives are a very important staple food for North African populations. The aim of this study was to analyze populations of Aspergillus section Flavi from local wheat based on aflatoxins (AFs), cyclopiazonic acid (CPA) and sclerotia production, and also to evaluate AFs-contaminated wheat collected from two different climatic regions in Algeria. A total of 108 samples of wheat were collected during the following phases: pre-harvest, storage in silos and after processing.

Dithiolopyrrolone antibiotic formation induced by adding valeric acid to the culture broth of Saccharothrix algeriensis.

Three new antibiotics were isolated from the fermentation broth of Saccharothrix algeriensis NRRL B-24137 and characterized as the dithiolopyrrolone derivatives valerylpyrrothine (1), isovalerylpyrrothine (2), and formylpyrrothine (3) as well as the known antibiotic aureothricin. The production of the dithiolopyrrolone derivatives was induced by adding valeric acid to the culture medium. The compounds exhibited moderate antimicrobial activity in vitro.

Eucalyptus (gracilis, oleosa, salubris, and salmonophloia) essential oils: their chemical composition and antioxidant and antimicrobial activities.

Essential oils of four different Eucalyptus species (Eucalyptus salubris, Eucalyptus salmonophloia, Eucalyptus oleosa, and Eucalyptus gracilis) grown in southern Tunisia were screened for their antioxidant and antimicrobial properties as well as their chemical compositions. According to gas chromatography-flame ionization detection and gas chromatography-mass spectrometry analysis, chemical compositions of the Eucalyptus species E. salubris (27 compounds; 99.