Determination of ETM, Histamine and Mycotoxins in Garba, a Traditional Ivoirian Meal

The methods of preparation, conservation and sale of Garba, the traditional Ivorian street meal, abundantly consumed in Côte d’Ivoire, can be exposed to various infections resulting in the poisoning of consumers. The aim of this study was to evaluate the hygienic quality of Garba through the analysis and the determination of certain toxic chemicals. In three hundred (300) samples of Garba collected in four districts in Abidjan, toxic metals (cadmium, mercury, lead), biogenic amine (histamine) and mycotoxins (aflatoxins and ochratoxin A) were detected and quantified using official standardized methods. Different toxics analyzed were present at various levels in the Garba. The mercury, lead, cadmium and histamine levels in the Garba were respectively 0.19 mg/kg, 0.19 mg/kg, 0.03 mg/kg and 32.69 mg/kg. The detected mycotoxins included aflatoxins B1, B2, G1, G2 and ochratoxin A, with respective average proportions of 3.44 μg/kg, 1.90 μg/kg, 8.07 μg/kg, 0.56 μg/kg and 0.42 μg/kg. The mycotoxins levels in the Garba are higher than the recommended toxic levels, particularly the ones in aflatoxin B1 and G1. This suggests a sanitary risk associated with the consumption of this meal. Consequently, awareness campaigns and training of the Garba sellers in hygiene and a better regulation of this sector by the competent authorities are required.

Edible Ectomycorrhizal Mushrooms Russula spp. of Côte d’Ivoire: Total Phenolic Content, HPLC-Profiles of Phenolic Compounds and Organic Acids, Antioxidant Activities

The aim of this study was to investigate the phenolic compounds content, HPLC-profiles of phenolic compounds and organic acids, and also antioxidant activities via the ability to scavenge DPPH radical of three wild edible mushrooms belonging to Russula genus and being collected in center of Côte d’Ivoire. Total phenolic compounds, flavonoids and tannins contents of methanolic extracts were assessed by colorimetric assays. So, the obtained values of these chemical parameters ranged from 394.05 to 513.50 mg/100 g DW, 94.50 to 139.95 mg/100 g DW and from 124.20 to 165 ± 0.54 mg/100 g DW, respectively. Otherwise, HPLC-profiles of the methanolic extracts revealed that quercetin, salicylic acid and tannin ol were the main phenolic compounds in R. delica whereas R. lepida contained gallic acid, catechin and protocatechuic acid as main phenolic compounds. Besides, it showed that the phenolic compounds such as salicylic acid, tannin ol and catechin were observed in R. mustelina. As for HPLC-profiles of organic acid, the fumaric and malic acid were recorded as the main organic acids in the three species of wild edible mushrooms. However, citric acid content was found to be highest in R. lepida. The methanolic extracts of the three mushrooms exhibited high DPPH radical scavenging activities ranging from 74.92% to 58.92%. These wild edible mushrooms could be considered a potential supply source of adequate natural antioxidant for local population.

Sequencing the Genome of a Marine Bacterium Called Pseudoalteromonas ulvae TC14 and Molecular Characterization of Its Communication System (Quorum Sensing)

The communication system known as quorum sensing (QS) in gram-negative bacteria regulates biofilm formation and many other functions. The particularity of Pseudoalteromonas ulvae TC14 seems to be the absence of a LuxI inducer, and therefore the lack of production of small molecules of Acyl homoserine lactone (AHL). Previous studies had shown that it does not harbor the inducer of the regulatory molecule (AHL). Nevertheless, it is able to regulate these same functions (biofilm, violacein) via AHLs. This could mean the presence of specific receptors for these induction molecules, belonging to the LuxR family. The aim of this study was to test these hypotheses using molecular analysis. Genome sequencing of the P. ulvae TC14 strain was carried out by Molecular Research LP (MR DNA), using the Illumina Hiseq 2500 method. The results revealed the presence of 2,293,242 base pairs, i.e. 100% of the genomic volume. The number of coding gene sequences was 1983, and the Guanine + Cytosine (G+C) percentage of the base number was 41.55%, revealing stability in the sequenced genome. In order to verify the identity of the sequenced genome, a phylogenetic analysis based on RNA16S was carried out. This analysis resulted in 93% homology with the previously sequenced and characterized species Pseudoalteromonas tunicata, showing that it belongs to the genus Pseudoalteromonas. To these comparative results should be added those derived from genome analysis based on nucleotide percentage using the tools available at https://img.jgi.doe.gov/. The results showed that Pseudoalteromonas tunicata D2 has the highest percentage nucleotide identity (ANI) (75.7913%), followed by Pseudoalteromonas flavipulchra NCIMB2033 (72.2736%) and Pseudoalteromonas phenolica KCTC 12086 (71.6685%). Next, the search for the various genes involved in QS was carried out using sequence comparisons via the BLAST method. For LuxI, sequence templates from the genomes of Vibrio, Chromobacterium, Shewanella or even other Pseudoalteromonas species were screened against the TC14 genome. This yielded no conclusive results synonymous with the non-presence of LuxI in TC14 as assumed by previous research. The search for LuxR, on the other hand, gave rise to the presence of eight presumptive sequences. Molecular characterization of the presumptive LuxR sequences was carried out to assess their gene expression. This characterization showed expression of these LuxR homologous sequences in a range from o.11 to 5.33 picograms (pg). Even if these sequences were not analyzed in depth, the retro-transcription technique nevertheless showed a minimum of activity, which could enable us to distinguish them from inactive sequences. The next step was to compare the LuxRs found in TC14 with the so-called Solo LuxRs, which act autonomously. This study shows that P. ulvae TC14 is a bacterium with a particular LuxR-based communication system.