Search results for "Bacillus"
showing 10 items of 774 documents
Beyond archaea: The table salt bacteriome
2021
Commercial table salt is a condiment with food preservative properties by decreasing water activity and increasing osmotic pressure. Salt is also a source of halophilic bacteria and archaea. In the present research, the diversity of halotolerant and halophilic microorganisms was studied in six commercial table salts by culture-dependent and culture-independent techniques. Three table salts were obtained from marine origins: Atlantic Ocean, Mediterranean (Ibiza Island), and Odiel marshes (supermarket marine salt). Other salts supplemented with mineral and nutritional ingredients were also used: Himalayan pink, Hawaiian black, and one with dried vegetables known as Viking salt. The results of…
Genomic Insights Into Five Strains of Lactobacillus plantarum With Biotechnological Potential Isolated From chicha, a Traditional Maize-Based Ferment…
2019
Lactic acid bacteria (LAB) are indigenous microorganisms that have been involved in food fermentations throughout history to preserve food and also to give special characteristics to them. The traditional fermented foods that are still being elaborated in indigenous populations around the world are a potential source of LAB with important biotechnological properties and/or beneficial to health. In a previous work, LAB biodiversity associated with chicha, a traditional maize-based fermented beverage from Northwestern Argentina, was studied, both by culture dependent and independent methods. From that study, 392 isolates were recovered, mostly members of Lactobacillus and Leuconostoc. Biotech…
Different Modes of Regulation of the Expression of Dextransucrase in Leuconostoc lactis AV1n and Lactobacillus sakei MN1
2019
Leuconostoc lactis AV1 strain isolated from a Tunisian avocado was characterized as a dextran producer. The promoter PdsrLL and the dsrLL gene encoding the DsrLL dextransucrase responsible for the dextran synthesis were transcriptionally fused to the mCherry coding gene generating the pRCR20 plasmid. Upon plasmid transfer, both AV1n and the dextran non-producing Leuconostoc mesenteroides CM70 became red due to expression of the mCherry from the PdsrLL-dsr-mrfp transcriptional fusion. Characterization of the polymers present in cultures supernatants revealed that the DsrLL encoded from pRCR20 in the recombinant bacteria was able to synthesize dextran. The production of dextran by the DsrLL i…
New Insights Into the Skin Microbial Communities and Skin Aging
2020
Although it is well-known that human skin aging is accompanied by an alteration in the skin microbiota, we know little about how the composition of these changes during the course of aging and the effects of age-related skin microbes on aging. Using 16S ribosomal DNA and internal transcribed spacer ribosomal DNA sequencing to profile the microbiomes of 160 skin samples from two anatomical sites, the cheek and the abdomen, on 80 individuals of varying ages, we developed age-related microbiota profiles for both intrinsic skin aging and photoaging to provide an improved understanding of the age-dependent variation in skin microbial composition. According to the landscape, the microbial composi…
Activity against Microorganisms Affecting Cellulosic Objects of the Volatile Constituents of Leonotis nepetaefolia from Nicaragua
2014
The chemical composition of the essential oil from aerial parts of L. nepetaefolia (L.) R. Br. collected in Nicaragua was evaluated by GC and GC-MS. The main components were ( Z)-phytol (22.8%), caryophyllene oxide (18.9%) and hexahydrofarnesylacetone (9.0%). The antibacterial activity against several Gram + and Gram - bacteria, including Bacillus cereus and B. subtilis, both infesting historical cellulosic material, was also determined. B. cereus, B. subtilis and Staphylococcus epidermis were the most affected by the action of the oil.
Bioaccumulation of selenium-by fruit origin lactic acid bacteria in tropical fermented fruit juices
2021
Abstract Adequate fruit consumption helps to prevent several chronic age-related diseases. Selenium (Se) is an elemental micronutrient with antioxidant capacity. In general, fruits and Se ingest by humans are below the recommended daily intake value. Fresh fruits are highly susceptible to deterioration during storage. Fermentation can improve the storage period, sensory profile, and bioactive compound content of foods; moreover, some lactic acid bacteria can accumulate organic Se intracellularly. In this work, microbial growth and Se accumulation by Levilactobacillus brevis CRL2051 and Fructobacillus tropaeoli CRL2034 in tropical fruit juices were evaluated. The strains could grow 1–2 log c…
Degradation of vanillic acid and production of guaiacol by microorganisms isolated from cork samples
2003
The presence of guaiacol in cork stoppers is responsible for some cases of cork taint causing unpleasant alterations to wine. We have performed a characterization of the cork-associated microbiota by isolating 55 different microorganisms: eight yeast, 14 filamentous fungi or molds, 13 actinomycetes and 20 non-filamentous bacteria. A screening for degradation of vanillic acid and guaiacol production showed that none of the filamentous fungi could achieve any of these processes. By contrast, five of the eight yeast strains isolated were able to degrade vanillic acid, although it was not converted to guaiacol. Guaiacol production was only detected in four bacterial strains: one isolate of Baci…
Molecular architecture and activation of the insecticidal protein Vip3Aa from Bacillus thuringiensis
2020
9 p.-5 fig.
Theoretical insights in enzyme catalysis
2004
In this tutorial review we show how the methods and techniques of computational chemistry have been applied to the understanding of the physical basis of the rate enhancement of chemical reactions by enzymes. This is to answer the question: Why is the activation free energy in enzyme catalysed reactions smaller than the activation free energy observed in solution? Two important points of view are presented: Transition State (TS) theories and Michaelis Complex (MC) theories. After reviewing some of the most popular computational methods employed, we analyse two particular enzymatic reactions: the conversion of chorismate to prephenate catalysed by Bacillus subtilis chorismate mutase, and a m…
Backbone dynamics of rusticyanin: the high hydrophobicity and rigidity of this blue copper protein is responsible for its thermodynamic properties.
2003
Local dynamics and solute-solvent exchange properties of rusticyanin (Rc) from Thiobacillus ferrooxidans have been studied by applying heteronuclear ((1)H, (15)N) NMR spectroscopy. (15)N relaxation parameters have been determined for the reduced protein, and a model-free analysis has been applied. The high average value of the generalized order parameter, S(2) (0.93), indicates that Rc is very rigid. The analysis of cross correlation rates recorded in both the reduced and the oxidized forms conclusively proves that Rc possesses the same dynamic features in both oxidation states. The accessibility of backbone amide protons to the solvent at different time scales has also been studied by appl…