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. The results revealed that among the Aspergillus species isolated, those belonging to section Flavi were predominant. Of the 150 strains of Aspergillus section Flavi isolated, 144 were identified as Aspergillus flavus and 6 as Aspergillus tamarii. We showed that 72% and 10% of the A. flavus strains produced AFs and CPA, respectively. Among the 150 strains tested, 60 produced amounts of AFB1 ranging from 12.1 to 234.6 lg/g of CYA medium. Also, we showed that most strains produced large sclerotia. AFB1was detected by HPLC in 56.6% of the wheat samples and derived products (flour, semolina and bran) with contamination levels ranging from 0.13 to 37.42 lg/kg

Occurrence of ochratoxin A in Algerian wheat and its milling derivatives

To determine the concentrations of ochratoxin A in wheat, and its derivatives, 81 samples, including durum wheat (n = 27), common wheat (n = 12), semolina (n = 29) and flour (n = 13) were collected from regions of Algeria. The results showed that 62 of the 81 samples (76.54%), were contaminated with quantities of ochratoxin A ranging from 0.84 to 34.75 µg/kg. The results showed that 69.23% of wheat grains were contaminated with ochratoxin A (0.21–27.31 µg/kg). Ochratoxin A were detected both in semolina and flour manufacturing process (0.16–34.75 µg/kg). Ochratoxin A level seem to be a serious public health problem in Algeria

Kinetic study of the growth of Saccharothrix algeriensis DSM 44581 in batch fermenter on a semi-synthetic medium in the presence of tiglic acid and methacrylic acid

This work aimed to investigate the effect of some nutriments (tiglic acid and methacrylic acid) on the growth of Saccharothrix algeriensis DSM 44581 on chemically defined medium (semi-synthetic medium) by using controlled batch fermenters. The controlled batch fermentations were conducted in the presence of tiglic and methacrylic acids. The growth rate of S. algeriensis in all fermentations was fast during the first 10 h of fermentation. The control culture showed a partially cell lysis in comparison to cultures with organic acids. This result showing that these organic acids could be used for biomass maintaining. The formation of biomass was influenced by the addition of organic acids. The experiment in the fermentor showed some differences with results obtained in Erlenmeyers

Polyphasic characterization of Aspergillus section Flavi isolated from animal feeds in Algeria

In Algeria, little information is available on the population structure of Aspergillus section Flavi in raw materials and resultant animal feeds. A total of 172 isolates belonging to Aspergillus section Flavi were recovered from 57 animal feeds and identified on the basis of macro and micro‐morphological characters, mycotoxin production and genetic relatedness. For the molecular analysis, sequencing of the calmodulin gene (CaM) and the internal transcribed spacer (ITS) regions were performed for representative isolates. Four distinct morphotypes were distinguished: Aspergillus flavus (78.5%), Aspergillus tamarii (19.2%), Aspergillus parasiticus (1.7%), and Aspergillus alliaceus (0.6%). All A. flavus isolates were of the L type and no correlation between sclerotia production and aflatoxigenicity was observed. Our results showed that 68% of the A. flavus strains produced aflatoxins B (AFB), and 72.7% were cyclopiazonic acid (CPA) producers. The three isolates of A. parasiticus were able to produce AFB and aflatoxins G but not CPA whereas, all the strains of A. tamarii produced only CPA. The obtained results revealed the presence of different species of Aspergillus section Flavi, among which were aflatoxin producers. This study provides evidence useful for considerations in aflatoxin control strategies

Isolation, Classification and Antagonistic Properties of Alkalitolerant Actinobacteria from Algerian Saharan Soils

The Sahara, one of the most extreme environments on Earth, constitutes an unexplored source of alkalitolerant actinobacteria. In this work, we studied the diversity of alkalitolerant actinobacteria in various soils collected from different regions of the Algerian Sahara. A total of 29 alkalitolerant actinobacterial strains were isolated by using a complex agar medium. The diversity of these actinobacteria was evaluated using a polyphasic approach, which included morphological, chemotaxonomic, physiological (numerical taxonomy) and 16S rRNA gene analyses. The isolates which were assigned to the genus Nocardiopsis, shared relatively low 16S rRNA gene sequences similarities compared to closely related species suggesting that they belonged to putatively new species. All of the strains were tested for antibiotic activity against a broad range of microorganisms and screened for genes encoding polyketide synthases and non-ribosomal peptide synthetases and found to have the potential to produce secondary metabolites. Consequently, the study supports the view that extreme environments contain many novel actinobacteria, which represent an unexplored source for the discovery of biologically active compounds

Biological activities of Streptomyces sp. Bts40 isolated from the rhizosphere of Artemisia herba-alba Asso

Actinobacteria isolated from the rhizosphere of plants are of interest as they produce a diverse range of molecules, such as antibiotics and enzymes. This study investigates the antibacterial activity, plant growth-promoting (PGP) abilities as well as the production of extracellular enzymes by the actinobacterial strain BTS40. This strain was isolated from the rhizospheric soil of the medicinal plant Artemisia herba-alba Asso that was naturally grown in a semi-arid environment. Morphological characteristics showed that the strain BTS40 belongs to the genus Streptomyces. Analysis of BTS40’s 16S rRNA gene sequence showed 99.45% similarity to Streptomyces alboniger NRRL B-1832T, in the EzTaxon database. This actinobacterium showed only antibacterial activity against Gram-positive bacteria. The strain also showed potential multiple traits for plant growth promotion and hydrolysis of enzymes. Hence, this study reveals that strain BTS40 has multiple PGP traits and produces many extracellular hydrolytic enzymes

Thermoactinomyces khenchelensis sp. nov., a filamentous bacterium isolated from soil sediment of a terrestrial hot spring

A novel thermophilic filamentous bacterium, designated strain T36T, was isolated from soil sediment sample from a hot spring source collected in Khenchela province, Algeria. Strain T36T was identified as a member of the genus Thermoactinomyces by a polyphasic approach. Strain T36T was observed to form white aerial mycelium and non-coloured to pale yellow substrate mycelium, both producing endospores, sessile or borne by short sporophores. The optimum growth temperature and pH were found to be 37–55 °C and 7.0–9.0, respectively and the optimum NaCl concentration for growth was found to be 0–7 % (w/v). The diagnostic diamino acid in the cell wall peptidoglycan was identified as meso-diaminopimelic acid. The predominant menaquinone of strain T36T was identified as MK-7 (H0). The major fatty acids were found to be iso-C15:0 and iso-C17:0. The phospholipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphoglycolipid. The chemotaxonomic properties of strain T36T are consistent with those shared by members of the genus Thermoactinomyces. 16S rRNA gene sequence analysis indicated that the sequence similarities between strain T36T and Thermoactinomyces species with validly published names were less than 98 %. Based on the combined genotypic and phenotypic evidence, it is proposed that strain T36T should be classified as representative of a novel species, for which the name Thermoactinomyces khenchelensis sp. nov. is proposed. The type strain is T36T (=DSM 45951T = CECT 8579T)

Incidence of mycobiota and aflatoxin B1 in Algerian feed

The presence of fungi and aflatoxin B1 (AFB1) in 101 animal feed samples randomly collected from different vendors and factories in Algeria was investigated. For fungi, the main genera isolated were Aspergillus, Penicillium and Fusarium. Furthermore, the 459 strains of Aspergillus section Flavi were screened for their ability to produce aflatoxins and cyclopiazonic acid. 49% of the strains produced AFB1. The highest incidence of aflatoxigenic strains was recorded in maize (61%) and ground poultry feed (60%). The presence of AFB1 in feed samples was evaluated using HPLC-FLD. The obtained data showed that 36.6% of samples were contaminated in the range of 0.34 to 171.06 μg/kg. Six samples exceeded the Algerian maximum limit of 20 µg/kg for AFB1. This study highlights the potential presence of aflatoxigenic strains belonging to section Flavi and AFB1 in animal feed at post-harvest in Algeria, strategic information for the Algerian policies makers

Struktura potencijalnih ditiolopirolonskih antibiotika detektirana iz DART-ToF-MS spektra ekstrakta kulture Saccharothrix algeriensis

Dithiolopyrrolone antibiotics, produced by the Saharan mycelial bacterium Saccharothrix algeriensis, are known for their potent biological activities. Biochemical profiling of S. algeriensis culture extract was done by direct analysis in real time and time-of-flight mass spectrometry (DART-ToF-MS). No other study on dithiolopyrrolones by this technique has been published. Eleven dithiolopyrrolone derivatives: thiolutin, butyryl-pyrrothine/iso-butyryl-pyrrothine, senecioyl-pyrrothine/tigloyl-pyrrothine, valeryl-pyrrothine/iso-valeryl-pyrrothine, 2-methyl-3-pentenyl-pyrrothine/2-hexonyl-pyrrothine, iso-hexanoyl-pyrrothine and benzoyl-pyrrothine were characterised by their exact mass measurement and the corresponding molecular formula of each compound. The obtained results confirmed that DART-ToF-MS is an appropriate confirmatory technique for powerful and rapid screening, as well as characterisation of bacterial secondary metabolites.Ditiolopirolonski antibiotici koje proizvodi saharska micelijska bakterije Saccharothrix algeriensis poznati su po svom snažnom biološkom djelovanju. Biokemijsko profiliranje ekstrakta kulture S. algeriensis učinjeno je direktnom analizom u realnom vremenu uz masenu spektrometriju vremena leta (DART-ToF-MS). Nije objavljena nijedna druga studija na ditiolopirolonima koja primjenjuje tu tehniku. Pronađeno je jedanaest derivata ditiolopirolona: tiolutin, butiril-pirotin/izo-butiril-pirotin, senecioil-pirotin/tigloil-pirotin, valeril-pirotin/izo-valeril-pirotin, 2-metil-3-pentenelin-pirotin/2-heksonil-pirotin, izo-heksanoil-pirotin i benzoil-pirotin. Dobiveni rezultati potvrdili su da je DART-ToF-MS prikladna tehnika za moćan i brzi “screening”, kao i za karakterizaciju sekundarnih metabolita bakterija

Exploration of actinobacteria communities in seawater and sediments of mediterranean basin from Algerian coast displays hight diversity with new taxa and antibacterial potential

The biodiversity of actinobacteria in the Mediterranean Sea habitat has drawn limited attention compared to that paid to terrestrial habitats. The work presented here focused on the biodiversity of culturable marine actinobacteria from sediments and seawater collected from the Algerian coast, and led to the identification of 114 actinobacterial isolates. The morphological study revealed higher actinobacterial diversity in sediment than in seawater. Fifty strains were selected for 16 S rRNAgene sequencing. The results revealed that the isolates belonged to ten different genera, Streptomyces (n = 17) and Micromonospora (n = 15) being the most dominant. The remaining actinobacterial isolates, identified as belonging to rare genera, included Nocardia (n = 5), Nocardiopsis (n = 3), Saccharothrix (n = 2), Rhodococcus (n = 2), Promicromonospora (n = 2), Nonomuraea (n = 2), Actinomadura (n = 1) and Saccharomonospora (n = 1). Interestingly, through 16 S rRNA sequence-based identification and phylogenetic analysis, two strains of the genus Streptomyces (MAT1 and MAS22) and a strain of the genus Nonomuraea (MAG8) both constituted a novel species. Screening of antibacterial activity of identified isolates against a panel of human pathogenic bacteria demonstrated that 36% of the isolates were active, particularly against Gram-positive bacteria. The ability to grow in the presence of NaCl and seawater revealed that 98% of the strains were halotolerant, with different levels of NaCl acceptance (from 3 to 13%) but no isolates required seawater to grow