Molecular Routes to Specific Identification of the Lactobacillus Casei Group at the Species, Subspecies and Strain Level

Abstract

The genus Lactobacillus includes, among others, Lactobacillus casei, Lactobacillus paracasei and Lactobacillus rhamnosus, species that are collectively referred to as the Lactobacillus casei group. Many studies have shown that strains belonging to this group may decrease lactose intolerance, the effects of inflammatory bowel disease, diarrhea, constipation, food allergies and even colon cancer. Moreover, evidences exists of positive effects of these bacteria on mucosal immunity and blood cholesterol level. Because of their beneficial influence on human health, many of them are used as food additives and probiotic pharmaceuticals. It should be stressed that health-promoting properties are not attributed at the species level, but to specific strains. Therefore, procedures are necessary to allow specific identification at each phylogenetic level—genus, species and strain. In this paper we present a practical overview of molecular methods for the identification and differentiation of L. casei bacteria. The research included 30 bacterial strains belonging to three species: L.casei, L. paracasei and L. rhamnosus. Among the tested procedures were genus- and species-specific PCR, multiplex-PCR, Real-Time HRM analysis, RFLP-PCR, rep-PCR, RAPD-PCR, AFLP-PCR, and proteomic methods such as MALDI-TOF MS typing and SDS-PAGE fingerprinting. The obtained results showed that multiplex-PCR and MALDI-TOF MS turned out to be the most useful methods to identify the tested bacteria at the species level. At the strain level, the AFLP-PCR method showed the highest discriminatory power. We hope that the presented results will allow for the easy selection of an appropriate procedure, depending on the experiment conducted and the equipment capabilities of any given laboratory.

Antimicrobial and Antioxidant Activities of Palm Kernel Oils Extracted from Varieties Dura and Tenera of Oil Palm (Elaeis guineensis Jacq.) and the Relationship to Their Chemical Composition

“…Among these saturated fatty acids, lauric acid was the predominant fatty acid with level of 50.69% ± 0.22 and 50.63% ± 0.19 respectively for oil D and oil T (Table 2). Similar results were obtained by Orsavova et al, (2015) with coconut oil. This lauric acid could decrease the ratio of total HDL cholesterol (Orsavova et al, 2015).…”

“…Similar results were obtained by Orsavova et al, (2015) with coconut oil. This lauric acid could decrease the ratio of total HDL cholesterol (Orsavova et al, 2015). Moreover, it has the greatest antimicrobial activity of all medium chain aliphatic fatty acids according to Ruzin and Novick (2000).…”

“…This lauric acid was the predominant fatty acid found in both oils analyzed. Similar results were obtained by Orsavova et al, (2015) with coconut oil. This lauric acid has another great activity.…”

“…This lauric acid has another great activity. Indeed, it could decrease the ratio of total HDL cholesterol (Orsavova et al, 2015). The undecylenic acid also has another great activity.…”

Comparison of Enzyme Secretion and Ferulic Acid Production by Escherichia coli Expressing Different Lactobacillus Feruloyl Esterases

“…Lactic acid bacteria are a group of Gram-positive bacteria that can ferment soluble carbohydrates to produce lactic acid. Many species of different genera belong to lactic acid bacteria, in which Lactobacillus is an important member ( Jarocki et al, 2020 ). Lactobacillus strains are widely distributed in human gut, dairy products, and fermented plant foods ( Duar et al, 2017 ).…”