RESUMEN
The presence of microorganisms (bacteria, protozoa, viruses, etc.) in water is a crucial indicator of its quality and safety. The detection of these microorganisms by conventional and classical techniques is widely used in water quality control laboratories; nevertheless these methods have limitations in terms of rapidity and precision of results. The use of Molecular Biology has been a great evolution in the techniques of water analysis. However, the choice of the concentration protocol allowing for the best rate of microorganism recovery in a suspension remains a real challenge. The objective of this experimental study is to compare the recovery rate of three different protocols of water concentration (membrane filtration, filtration on gauze pad and centrifugation) for samples intended for analysis by polymerase chain reaction PCR. Which can then serve as a reference protocol for water quality control laboratories. The experimental results have shown that the membrane filtration protocol yields the best recovery rate and concentration of microorganisms followed by filtration on gauze pad, while the centrifugation protocol (8000g, 10 min, 22 °C) gives the lowest rate of recovery out of the three protocols. The experimental results obtained through this study allows us to contribute to the optimization and standardization of water samples concentration techniques intended for analysis by Molecular Biology.
RESUMEN
COVID-19 is an infectious disease caused by the newly discovered SARS-CoV-2 virus. This virus causes a respiratory tract infection, symptoms include dry cough, fever, tiredness and in more severe cases, breathing difficulty. SARS-CoV-2 is an extremely contagious virus that is spreading rapidly all over the world and the scientific community is working tirelessly to find an effective treatment. This paper aims to determine the origin of this virus by comparing its nucleic acid sequence with all members of the coronaviridae family. This study uses a new approach based on the combination of three powerful techniques which are: Ngrams (For text categorization), Principal Component Analysis (For dimensionality reduction) and Random Forest algorithm (For supervised classification). The experimental results have shown that a large set of SARS-CoV-2 genomes, collected from different locations around the world, present significant similarities to those found in pangolins. This finding confirms some previous results obtained by other methods, which also suggest that pangolins should be considered as possible hosts in the emergence of the new coronavirus.
RESUMEN
In the present study, the multi-occurrence of twenty (20) mycotoxins in pasta samples consumed in Morocco was assessed. For this, a modified Quick, Easy, Cheap Effective, Rugged, and Safe method was validated. The mycotoxins studied were identified and quantified by liquid chromatographyâ»tandem mass spectrometry (LCâ»MS/MS) and gas chromatographyâ»tandem mass spectrometry (GC-MS/MS). The validated method was applied to one hundred and six (n = 106) pasta samples purchased from several areas in the country. The analytical results showed that 99 out of 106 total samples (93.4%) were contaminated with at least one mycotoxin. Nine mycotoxins (Aflatoxin B1, Enniatin B, Enniatin B1, Enniatin A1, Zearalenone, Deoxynivalenol, 3-Acetyl-Deoxynivalenol, T-2, and HT-2 toxins) were present in the pasta samples. Enniatin B and Enniatin B1 were the predominant mycotoxins. The Zearalenone, Deoxynivalenol, HT-2, and T-2 toxins were present in 51.8%, 43.5%, 34.9%, and 16% of samples, respectively. Aflatoxin B1 was detected in only 2 samples. Risk exposure assessment concluded that mycotoxin levels found in pasta do not pose a significant human health risk for the Moroccan population. This is the first paper drafted on the multi-occurrence of mycotoxins in pasta from this country.