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The detection of coronavirus disease 2019 cases represents a significant challenge at the epidemiological level. Limitations exist in effectively detecting asymptomatic cases, achieving good follow-up in hospitals without the infrastructure for reverse transcription-quantitative PCR (RT-qPCR) or in difficult-to-access areas and developing methods with the need for less invasive sampling procedures. Therefore, the present study evaluated the performance of the direct reverse transcription loop-mediated isothermal amplification (RT-LAMP) test for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the saliva and nasal samples of asymptomatic individuals belonging to the university population. In addition, this test was also assessed for effectiveness in symptomatic individuals referred from a hospital with poor infrastructure in molecular biology and located outside the urban area. The RT-LAMP assay was compared with the results obtained from the RT-qPCR nasopharyngeal swab test, where the diagnosis was confirmed by lateral flow immunoassay test for rapid antigen detection. A total of 128 samples were analyzed, of which 43% were symptomatic positive individuals, 25% were asymptomatic positive individuals and 32% were SARS-CoV2-negative control individuals. Among positive individuals, no differences were found between the Cq values determined by RT-qPCR. A sensitivity of 96.5% and a specificity of 97.6% was reported for the detection of SARS-CoV-2 in symptomatic individuals by salivary and nasal RT-LAMP, as well as a sensitivity of 100% and a specificity of 97.6% for the detection of SARS-CoV-2 in asymptomatic individuals. These findings indicated that performance of the direct RT-LAMP test using saliva and nasal samples has high sensitivity and specificity, which in turn suggest that it is a viable and reliable alternative for use in epidemiological monitoring. [ABSTRACT FROM AUTHOR]

Background: Millenary fermented beverages are a source of industrially important microorganisms. Aguamiel and pulque are traditional Mexican beverages of pre-Hispanic origin, with a microbial diversity that contributes to the different fermentations (lactic, alcoholic and acetic). The aim of this research was to characterize the Bacillus mojavensis (BF2A1) strain isolated from aguamiel and determine its probiotic potential. The strain was identified through Mass Spectrometry (MS), molecular techniques, as well as morphological and biochemical profiling. The probiotic activity of the BF2A1 strain and its response during the gastric simulation was determined. Results: The strain BF2A1 is a Gram-positive, spore-forming bacillus, positive for catalase, gammahemolysis, citrate, ornithine, grows at 7.5% NaCl, and acetoin, but negative for motility, indole, and methyl red. Its taxonomic identity was determined as B. mojavensis both by MALDI-TOF MS and sequencing of 16S rDNA. Its probiotic potential was demonstrated as BF2A1 was tolerant to pH 2 (OD620nm 0.2 89 ± 0.012), 0.3% bile salts (OD620nm 0.103 ± 0.089), 8% NaCl (OD620nm 0.254 ± 0.096), and 1% lysozyme (OD620nm 1.342 ± 0.078) compared to the probiotic strain Lactobacillus leichmannii ATCC 7830TM (Laclei). The antagonistic effect of BF2A1 against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923), and Candida albicans (ATCC60193) showed 25.5%, 8% and, 65% inhibitory growing effect, respectively. BF2A1 in the gastric simulation showed only a reduction of 1-2 log CFU/mL and showed after the intestinal phase a survival rate of 84.4% as compared to the control strains. Conclusions: This study shows that BF2A1 isolated from aguamiel is a bacterium with probiotic properties that can be used in different areas of Biotechnology. [ABSTRACT FROM AUTHOR]

Background: Palmitoleic acid is a fatty acid that possesses nutritional, health, and industrial applications. However, it accumulates in the seed oil of few plant species that often lack agronomic value. A bioinformatics approach was developed as a complementary tool to effort- and time-consuming traditional methods to identify palmitoleic acid-accumulating plant species. The approach involved identifying acyl-ACP desaturases with a sequence variation linked to a switch in the substrate preference from stearic to palmitic acid. Results: A PHI-BLAST analysis identified Handroanthus impetiginosus as a candidate species with two acyl- ACP desaturases with the desired sequence variation. A substrate docking analysis showed that the presence of phenylalanine at the bottom of the active site plays a similar structural role to that of tryptophan present in the same position in the divergent desaturase of the palmitoleic acid accumulator Dolichandra unguis-cati. The analysis of the genome of H. impetiginosus allowed the identification of four putative ferredoxins, three of which are heterotrophic type and have been linked to an increase in the activity of unusual acyl-ACP desaturases. RT-PCR results showed that both studied H. impetiginosus desaturases are expressed in the pod but not in the seeds, while all 4 ferredoxins are expressed in both tissues. GC–MS analysis confirmed the presence of palmitoleic acid in seed oil. Conclusions: These results suggest that the proposed bioinformatic approach can be a valuable compliment to traditional methods for the identification of plant species that accumulate palmitoleic acid. However, further improvements are needed, such as predicting seed expression of desaturases. [ABSTRACT FROM AUTHOR]