Galacto-oligosaccharide production by ssp. whole cells and lysates.

β-Galactosidase is currently applied in foods for reduction of lactose but can also be used for its transgalactosylation activity to synthesize galacto-oligosaccharides (GOS) as prebiotics. The ability of GRAS-status strains to exhibit such activities would benefit consumers given their extensive history with dairy products. The objective of this study was to characterize the production of GOS in 6 strains for their ability to synthesize GOS in 50 m sodium phosphate (pH 6.

BlpU is a broad-spectrum bacteriocin in .

strain B59671 naturally produces thermophilin 110, a broad-spectrum bacteriocin encoded within the bacteriocin-like peptide () gene cluster, and thermophilin 13 from a separate chromosomal locus. Analysis of the gene cluster revealed two genes, and , as potentially encoding bacteriocins. Deletion of from the B59671 chromosome did not result in a loss of antimicrobial activity against either ST113 or F.

The quorum sensing peptide BlpC regulates the transcription of genes outside its associated gene cluster and impacts the growth of .

Bacteriocin production in is regulated by cell density-dependent signaling molecules, including BlpC, which regulates transcription from within the bacteriocin-like peptide () gene cluster. In some strains, such as ST106, this signaling system does not function properly, and BlpC must be supplied exogenously to induce bacteriocin production. In other strains, such as B59671, bacteriocin (thermophilin 110 in strain B59671) production occurs naturally.

Retrospective Evaluation of Drug-Drug Interactions With Erlotinib and Gefitinib Use in the Military Health System.

Background: Erlotinib and gefitinib are epidermal growth factor receptor-tyrosine kinase inhibitors approved for non-small cell lung cancer treatment by the US Food and Drug Administration. Drug-drug interactions (DDIs) with these agents are vague and poorly understood. Because DDIs can have an effect on clinical outcomes, we aimed to identify drugs that interact with erlotinib or gefitinib and describe their clinical manifestations.

Antimicrobial activity of thermophilin 110 against the opportunistic pathogen Cutibacterium acnes.

Objective: Thermophilin 110, a bacteriocin produced by Streptococcus thermophilus B59671, inhibited planktonic growth and biofilm formation of Cutibacterium acnes, a commensal skin bacterium associated with the inflammatory disease, acne vulgaris, and more invasive deep tissue infections.

Results: Thermophilin 110 prevented planktonic growth of C. acnes at a concentration ≥ 160 AU mL; while concentrations ≥ 640 AU mL resulted in a > 5 log reduction in viable planktonic cell counts and inhibited biofilm formation.

Differential behavior of Lactobacillus helveticus B1929 and ATCC 15009 on the hydrolysis and angiotensin-I-converting enzyme inhibition activity of fermented ultra-high-temperature milk and nonfat dried milk powder.

Consumers' growing interest in fermented dairy foods necessitates research on a wide array of lactic acid bacterial strains to be explored and used. This study aimed to investigate the differences in the proteolytic capacity of Lactobacillus helveticus strains B1929 and ATCC 15009 on the fermentation of commercial ultra-pasteurized (UHT) skim milk and reconstituted nonfat dried milk powder (at a comparable protein concentration, 4%). The antihypertensive properties of the fermented milk, measured by angiotensin-I-converting enzyme inhibitory (ACE-I) activity, were compared.

Stability for 6 months and accuracy of a specific enteral caffeine base preparation for a multisite clinical trial.

The 'Intermittent Hypoxia and Caffeine in Infants Born Preterm (ICAF)' study (NCT03321734) uses an extemporaneously compounded enteral caffeine base solution for its study drug. The primary aim of this report is to determine the stability of this specific enteral caffeine base preparation stored for up to 6 months and assess optimal storage temperature. To analyse stability, caffeine solutions were prepared and stored at 4°C and 25°C (room temperature).

Pre-clinical drug-drug interaction (DDI) of gefitinib or erlotinib with Cytochrome P450 (CYP) inhibiting drugs, fluoxetine and/or losartan.

Objective: To evaluate drug-drug interactions (DDIs) between gefitinib or erlotinib with fluoxetine, and/or losartan.

Methods: Human pooled microsomes, supersomes, and cryopreserved human hepatocytes were used to monitor DDIs . RED (Rapid Equilibrium Dialysis) protein binding was employed to investigate other pharmacokinetics.

Electricity from methane by reversing methanogenesis.

Given our vast methane reserves and the difficulty in transporting methane without substantial leaks, the conversion of methane directly into electricity would be beneficial. Microbial fuel cells harness electrical power from a wide variety of substrates through biological means; however, the greenhouse gas methane has not been used with much success previously as a substrate in microbial fuel cells to generate electrical current. Here we construct a synthetic consortium consisting of: (i) an engineered archaeal strain to produce methyl-coenzyme M reductase from unculturable anaerobic methanotrophs for capturing methane and secreting acetate; (ii) micro-organisms from methane-acclimated sludge (including Paracoccus denitrificans) to facilitate electron transfer by providing electron shuttles (confirmed by replacing the sludge with humic acids), and (iii) Geobacter sulfurreducens to produce electrons from acetate, to create a microbial fuel cell that converts methane directly into significant electrical current.

Metabolic engineering of Methanosarcina acetivorans for lactate production from methane.

We previously demonstrated anaerobic conversion of the greenhouse gas methane into acetate using an engineered archaeon that produces methyl-coenzyme M reductase (Mcr) from unculturable microorganisms from a microbial mat in the Black Sea to create the first culturable prokaryote that reverses methanogenesis and grows anaerobically on methane. In this work, we further engineered the same host with the goal of converting methane into butanol. Instead, we discovered a process for converting methane to a secreted valuable product, L-lactate, with sufficient optical purity for synthesizing the biodegradable plastic poly-lactic acid.

Toxin YafQ Reduces Escherichia coli Growth at Low Temperatures.

Toxin/antitoxin (TA) systems reduce metabolism under stress; for example, toxin YafQ of the YafQ/DinJ Escherichia coli TA system reduces growth by cleaving transcripts with in-frame 5'-AAA-G/A-3' sites, and antitoxin DinJ is a global regulator that represses its locus as well as controls levels of the stationary sigma factor RpoS. Here we investigated the influence on cell growth at various temperatures and found that deletion of the antitoxin gene, dinJ, resulted in both reduced metabolism and slower growth at 18°C but not at 37°C. The reduction in growth could be complemented by producing DinJ from a plasmid.

Reversing methanogenesis to capture methane for liquid biofuel precursors.

Background: Energy from remote methane reserves is transformative; however, unintended release of this potent greenhouse gas makes it imperative to convert methane efficiently into more readily transported biofuels. No pure microbial culture that grows on methane anaerobically has been isolated, despite that methane capture through anaerobic processes is more efficient than aerobic ones.

Results: Here we engineered the archaeal methanogen Methanosarcina acetivorans to grow anaerobically on methane as a pure culture and to convert methane into the biofuel precursor acetate.

YeeO from Escherichia coli exports flavins.

Multidrug and toxic compound extrusion (MATE) proteins help maintain cellular homeostasis by secreting metabolic wastes. Flavins may occur as cellular waste products, with their production and secretion providing potential benefit for industrial applications related to biofuel cells. Here we find that MATE protein YeeO from Escherichia coli exports both flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).

RalR (a DNase) and RalA (a small RNA) form a type I toxin-antitoxin system in Escherichia coli.

For toxin/antitoxin (TA) systems, no toxin has been identified that functions by cleaving DNA. Here, we demonstrate that RalR and RalA of the cryptic prophage rac form a type I TA pair in which the antitoxin RNA is a trans-encoded small RNA with 16 nucleotides of complementarity to the toxin mRNA. We suggest the newly discovered antitoxin gene be named ralA for RalR antitoxin.

Toxin GhoT of the GhoT/GhoS toxin/antitoxin system damages the cell membrane to reduce adenosine triphosphate and to reduce growth under stress.

Toxin/antitoxin (TA) systems perhaps enable cells to reduce their metabolism to weather environmental challenges although there is little evidence to support this hypothesis. Escherichia coli GhoT/GhoS is a TA system in which toxin GhoT expression is reduced by cleavage of its messenger RNA (mRNA) by antitoxin GhoS, and TA system MqsR/MqsA controls GhoT/GhoS through differential mRNA decay. However, the physiological role of GhoT has not been determined.

Genome-scale modeling using flux ratio constraints to enable metabolic engineering of clostridial metabolism in silico.

Background: Genome-scale metabolic networks and flux models are an effective platform for linking an organism genotype to its phenotype. However, few modeling approaches offer predictive capabilities to evaluate potential metabolic engineering strategies in silico.

Results: A new method called "flux balance analysis with flux ratios (FBrAtio)" was developed in this research and applied to a new genome-scale model of Clostridium acetobutylicum ATCC 824 (iCAC490) that contains 707 metabolites and 794 reactions.