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Lactic acid bacteria (LAB) cause the majority of beer spoilage incidents in the brewing industry. Previous studies revealed that the hop resistance genes, horA and horC, are applicable to the species-independent determination of beer spoilage ability of LAB. However, novel beer spoilage LAB species are occasionally emerging, and their insights should be shared in the industry to prevent spoilage incidents by these unknown species. In this study, Lactobacillus nagelii ABBC668 strain, isolated from spoiled pilsner-type beer, was investigated, as L. nagelii has been poorly characterized as a beer spoiler. The beer spoilage ability and hop resistance genes of L. nagelii ABBC668 were examined. Results showed that L. nagelii ABBC668 harbored hop resistance gene horA and exhibited beer spoilage ability. Also, it was considered that horA harbored by ABBC668 was acquired via horizontal gene transfer and had an unstable nature compared to that of Lactobacillus brevis. The unstable nature may account for the less frequent encounter of beer spoilage L. nagelii strains in the brewing industry. Furthermore, ABBC668 showed similar motility to other L. nagelii strains. To our knowledge, this is the first report of L. nagelii as a beer spoilage species. [ABSTRACT FROM AUTHOR]

Purpose: To determine the nutraceutical effect of mixtures containing Lactobacillus nagelii/betanin on the carbohydrate and lipid metabolism of mice. Methods: Lactobacillus nagelii and betanin were isolated from the raw materials. These components were subsequently assessed for their anti-hyperglycemic and hypolipidemic activities, and administered individually or combined in normoglycemic and diabetic mice. These animals were subjected to a standard OGTT and given an atherogenic diet. Results: The combination of L. nagelii (2.0 × 109 CFU/mL) and betanin (30 mg/kg body weight) exerted a significant (p < 0.01) and prolonged reduction of postprandial blood glucose (30 - 120 min). Interestingly, a mixture of L. nagelii (1 ×107 CFU/mouse/day) with betanin (10 mg/kg body weight) administered for 30 days, produced favourable effects (p < 0.01) in the lipid profile of mice previously treated with an atherogenic diet. These mixtures significantly ameliorated (p < 0.01) hypoinsulinemia, hyperleptinemia and increased the levels of adiponectin. Conclusion: The simultaneous administration of L. nagelii and betanin in mice produced a beneficial change in blood glucose and lipids in mice, indicating a synergistic nutraceutical effect. However, there is a need to develop this therapy further for potential application in humans [ABSTRACT FROM AUTHOR]

Water kefir is a slightly alcoholic and traditionally fermented beverage, which is prepared from sucrose, water, kefir grains, and dried or fresh fruits (e.g., figs). Lactobacillus (L.) nagelii, L. hordei, and Saccharomyces (S.) cerevisiae are predominant and stable lactic acid bacteria and yeasts, respectively, isolated from water kefir consortia. The growth of L. nagelii and L. hordei are improved in the presence of S. cerevisiae. In this work we demonstrate that quantitative comparative proteomics enables the investigation of interactions between LAB and yeast to predict real-time metabolic exchange in water kefir. It revealed 73 differentially expressed (DE) in L. nagelii TMW 1.1827 in the presence of S. cerevisiae. The presence of the yeast induced changes in the changes in the carbohydrate metabolism of L. nagelii and affected reactions involved in NAD+/NADH homeostasis. Furthermore, the DE enzymes involved in amino acid biosynthesis or catabolism predict that S. cerevisiae releases glutamine, histidine, methionine, and arginine, which are subsequently used by L. nagelii to ensure its survival in the water kefir consortium. In co-culture with S. cerevisiae, L. nagelii profits from riboflavin, most likely secreted by the yeast. The reaction of L. nagelii to the presence of S. cerevisiae differs from that one of the previously studied L. hordei, which displays 233 differentially expressed proteins, changes in citrate metabolism and an antidromic strategy for NAD+/NADH homeostasis. So far, aggregation promotion factors, i.e., formation of a specific glucan and bifunctional enzymes were only detected in L. hordei.

Water kefir is a slightly alcoholic and traditionally fermented beverage, which is prepared from sucrose, water, kefir grains, and dried or fresh fruits (e.g., figs). Lactobacillus (L.) nagelii, L. hordei , and Saccharomyces (S.) cerevisiae are predominant and stable lactic acid bacteria and yeasts, respectively, isolated from water kefir consortia. The growth of L. nagelii and L. hordei are improved in the presence of S. cerevisiae. In this work we demonstrate that quantitative comparative proteomics enables the investigation of interactions between LAB and yeast to predict real-time metabolic exchange in water kefir. It revealed 73 differentially expressed (DE) in L. nagelii TMW 1.1827 in the presence of S. cerevisiae. The presence of the yeast induced changes in the changes in the carbohydrate metabolism of L. nagelii and affected reactions involved in NAD+/NADH homeostasis. Furthermore, the DE enzymes involved in amino acid biosynthesis or catabolism predict that S. cerevisiae releases glutamine, histidine, methionine, and arginine, which are subsequently used by L. nagelii to ensure its survival in the water kefir consortium. In co-culture with S. cerevisiae, L. nagelii profits from riboflavin, most likely secreted by the yeast. The reaction of L. nagelii to the presence of S. cerevisiae differs from that one of the previously studied L. hordei , which displays 233 differentially expressed proteins, changes in citrate metabolism and an antidromic strategy for NAD+/NADH homeostasis. So far, aggregation promotion factors, i.e., formation of a specific glucan and bifunctional enzymes were only detected in L. hordei. [ABSTRACT FROM AUTHOR]

Dextransucrases are extracellular enzymes, which are exclusively expressed by lactic acid bacteria (LAB) and produce α-1→6 linked glucose polymers from sucrose. In this study, two dextransucrases derived from water kefir borne Lactobacillus hordei TMW 1.1822 and Lactobacillus nagelii TMW 1.1827 were identified and comparatively investigated. Differences between both proteins mainly arise from an additional C-terminal glucan-binding domain and the presence of a signal motif in the L. nagelii TMW 1.1827 dextransucrase. L. hordei TMW 1.1822 released the enzyme only in the presence of its substrate sucrose in contrast to L. nagelii TMW 1.1827, while both strains functionally expressed the dextransucrases independently of sucrose. Both enzymes could be recovered as crude protein extracts in culture supernatants, as they are not covalently bound to the cell surface. This enabled the formation of dextrans at equal reaction conditions as well as their subsequent structural analysis in terms of molecular structure and molecular weight. The volumetric transglycosylation and hydrolysis activities were distinctly different for both enzymes, which produced O3 -branched dextrans with a comparable degree of branching. Moreover, identical oligosaccharides were obtained for both dextrans upon endo -dextranase digestion, while some differences in the polysaccharide fine structures could be identified from the varying portions of certain oligosaccharides. Dextrans synthesized by the dextransucrase released by L. nagelii exhibited an averaged molecular weight ( M w ) of 7.9×10 7 Da, while those produced by the dextransucrase released by L. hordei exhibited an M w of 6.1×10 7 Da. Moreover, glycosylation of glucansucrases by LAB was identified for the first time for the released dextransucrase of L. nagelii TMW 1.1827. Our study therefore reveals new molecular insights into how dextransucrases released by water kefir borne L. hordei TMW 1.1822 and L. nagelii TMW 1.1827 contribute to the complex formation of the traditional beverage water kefir.

Sugarcane vinegar is produced in various countries of southern Asia. It is also a niche product of the Kagoshima and Okinawa Prefectures in Japan. Turbid compounds are sometimes found in sugarcane vinegar, thereby lowering the market value. In this study, the turbid compounds were precipitated with a 1:2 (v/v) volume of ethanol, and they were identified as α-1,6-glucan using enzymatic digestion tests and 13 C nuclear magnetic resonance analysis. Moreover, Lactobacillus nagelii was isolated from sugarcane juice, and it produced α-1,6-glucan when grown with sugar. The turbid compounds found in sugarcane vinegar were assumed to be α-1,6-glucan produced from sugar by lactic acid bacteria that exist in sugarcane juice., (2016 by The Japanese Society of Applied Glycoscience.)