Levilactobacillus brevis with High Production of Putrescine Isolated from Blue Cheese and Its Application.

Polyamine intake has been reported to help extend the lifespan of animals. Fermented foods contain high concentrations of polyamines, produced by fermenting bacteria. Therefore, the bacteria, isolated from fermented foods that produce large amounts of polyamines, are potentially used as a source of polyamines for humans. In this study, the strain Levilactobacillus brevis FB215, which has the ability to accumulate approximately 200 µM of putrescine in the culture supernatant, was isolated from fermented foods, specifically the Blue Stilton cheese. Furthermore, L. brevis FB215 synthesized putrescine from agmatine and ornithine, which are known polyamine precursors. When cultured in the extract of Sakekasu, a byproduct obtained during the brewing of Japanese rice wine containing high levels of both agmatine and ornithine, L. brevis FB215 grew to OD600 = 1.7 after 83 h of cultivation and accumulated high concentrations (~1 mM) of putrescine in the culture supernatant. The fermentation product also did not contain histamine or tyramine. The Sakekasu-derived ingredient fermented by the food-derived lactic acid bacteria developed in this study could contribute to increasing polyamine intake in humans.

Phylogenomic analysis in Latilactobacillus sakei by using polymorphisms detected by next-generation sequencing.

Latilactobacillus sakei is a lactic acid bacterium used to produce a wide range of fermented food products. To understand their characteristics and adaptability to various nutrient sources, we applied strain-specific, nucleotide-concatenated (SSC) sequences to the phylogenetic analysis of 32 L. sakei strains isolated from various locations and products. SSC sequences were developed by concatenating the polymorphisms detected by whole-genome sequencing. This enabled us to use sufficient polymorphisms and avoid the bias caused by selecting partial sequences, such as that in core genome and multi-locus sequence typing. SSC sequence-based analysis revealed that the phylogenetic relations for L. sakei are based on the different nutrition sources rather than geographical distance.

Research overview of L-DOPA production using a bacterial enzyme, tyrosine phenol-lyase.

L-DOPA is an amino acid that is used as a treatment for Parkinson's disease. A simple enzymatic synthesis method of L-DOPA had been developed using bacterial L-tyrosine phenol-lyase (Tpl). This review describes research on screening of bacterial strains, culture conditions, properties of the enzyme, reaction mechanism of the enzyme, and the reaction conditions for the production of L-DOPA. Furthermore, molecular bleeding of constitutively Tpl-overproducing strains is described, which were developed based on mutations in a DNA binding protein, TyrR, which controls the induction of tpl gene expression.

Isolation of the high polyamine-producing bacterium Staphylococcus epidermidis FB146 from fermented foods and identification of polyamine-related genes.

It has been reported that the intake of polyamines contributes to the extension of healthy life span in animals. Fermented foods contain high concentrations of polyamines thought to be derived from fermentation bacteria. This suggests that bacteria that produce high levels of polyamines could be isolated from fermented foods and utilized as a source of polyamines for human nutrition. In this study, Staphylococcus epidermidis FB146 was isolated from miso, a Japanese fermented bean paste, and found to have a high concentration of putrescine in its culture supernatant (452 µM). We analyzed the presence of polyamines in the culture supernatants and cells of the type strains of 21 representative Staphylococcus species in addition to S. epidermidis FB146, and only S. epidermidis FB146 showed high putrescine productivity. Furthermore, whole-genome sequencing of S. epidermidis FB146 was performed, and the ornithine decarboxylase gene (odc), which is involved in putrescine synthesis, and the putrescine:ornithine antiporter gene (potE), which is thought to contribute to the release of putrescine into the culture supernatant, were present on plasmid DNA harbored by S. epidermidis FB146.

Gut bacterial aromatic amine production: aromatic amino acid decarboxylase and its effects on peripheral serotonin production.

Colonic luminal aromatic amines have been historically considered to be derived from dietary source, especially fermented foods; however, recent studies indicate that the gut microbiota serves as an alternative source of these amines. Herein, we show that five prominent genera of Firmicutes (Blautia, Clostridium, Enterococcus, Ruminococcus, and Tyzzerella) have the ability to abundantly produce aromatic amines through the action of aromatic amino acid decarboxylase (AADC). In vitro cultivation of human fecal samples revealed that a significant positive correlation between aadc copy number of Ruminococcus gnavus and phenylethylamine (PEA) production. Furthermore, using genetically engineered Enterococcus faecalis-colonized BALB/cCrSlc mouse model, we showed that the gut bacterial aadc stimulates the production of colonic serotonin, which is reportedly involved in osteoporosis and irritable bowel syndrome. Finally, we showed that human AADC inhibitors carbidopa and benserazide inhibit PEA production in En. faecalis.

Putrescine Production by Latilactobacillus curvatus KP 3-4 Isolated from Fermented Foods.

Polyamines are aliphatic hydrocarbons with terminal amino groups and are essential for biological activities. It has been reported that polyamines have health-promoting effects in animals, such as the extension of lifespan by polyamine intake. The identification of a high polyamine-producing bacterium from foods could lead to the development of a novel probiotic candidate. We aimed to identify high polyamine-producing bacteria from food, and isolated and collected bacteria from vegetables and fermented foods produced in Japan. We successfully acquired Latilactobacillus curvatus KP 3-4 isolated from Kabura-zushi as a putrescine producing lactic acid bacteria. Comparing the polyamine synthesis capability of L. curvatus KP 3-4 with that of typical probiotic lactic acid bacteria and L. curvatus strains available from the Japan Collection of Microorganisms, it was found that only L. curvatus KP 3-4 was capable of exporting high levels of putrescine into the culture supernatant. The enhancement of putrescine production by the addition of ornithine, and whole-genome analysis of L. curvatus KP 3-4, suggest that putrescine is synthesized via ornithine decarboxylase. The administration of L. curvatus KP 3-4 to germ-free mice increased the concentration of putrescine in the feces.

Thermococcus sp. KS-1 PPIase as a fusion partner improving soluble production of aromatic amino acid decarboxylase.

Peptidyl-prolyl cis-trans isomerase (PPIase, EC 5.2.1.8) catalyzes the racemization reaction of proline residues on a polypeptide chain. This enzyme is also known to function as a molecular chaperon to stabilize protein conformation during the folding process. In this study, we noted FK506 binding protein (FKBP)-type PPIase from a hyperthemophilic archaeon Thermococcus sp. strain KS-1 (PPIase KS-1) to improve the solubility of Pseudomonas putida aromatic amino acid decarboxylase (AADC) that is an indispensable enzyme for fermentative production of plant isoquinoline alkaloids. AADC fused N-terminally with the PPIase KS-1 (PPIase KS-1-AADC), which was synthesized utilizing Escherichia coli host, showed improved solubility and, consequently, the cell-free extract from the recombinant strain exhibited 2.6- to 3.4-fold elevated AADC activity than that from the control strain that expressed the AADC gene without PPIase KS-1. On the other hand, its thermostability was slightly decreased by fusing PPIase KS-1. The recombinant E. coli cells expressing the PPIase KS-1-AADC gene produced dopamine and phenylethylamine from L-dopa and phenylalanine by two- and threefold faster, respectively, as compared with the control strain. We further demonstrated that the efficacy of PPIase KS-1-AADC in solubility and activity enhancement was a little but obviously higher than that of AADC fused N-terminally with NusA protein, which has been assumed to be the most effective protein solubilizer. These results suggest that PPIase KS-1 can be used as one of the best choices for producing heterologous proteins as active forms in E. coli.

Changes in Microbiota During Multiple Fermentation of Kefir in Different Sugar Solutions Revealed by High-Throughput Sequencing.

Kefir is a fermented beverage produced through the activity of its grains, which is constituted by lactic acid and acetic acid bacteria and yeasts. We studied the bacterial succession during multiple fermentation of Argentinian kefir in brown sugar, purified molasses or high-test molasses, using 16S high-throughput sequencing. Firmicutes was dominant (up to 98% of total population) in grains and beverages made from various sugar substrates, except in high-test molasses beverage, which was dominated by Proteobacteria (up to 78% of total population). Major bacterial species in Firmicutes were Liquorilactobacillus nagelii, Lentilactobacillus hilgardii/diolivorans and Lacticaseibacillus casei/paracasei, which are active in lactic acid fermentation. Proteobacteria comprised Acetobacter lovaniensis and Gluconobacter oxydans/roseus as major species, which are presumably responsible for the acetic acid formation in sugary kefir beverages. Bacteria differ in abundance depending on the sugar type, as revealed by the competitive dominances between L. nagelii and A. loveniensis. Purified molasses led to scarce acetic acid bacteria during fermentation, indicating that it is not a suitable substrate for their growth. Our results suggest that acetic acid (and/or ethanol) in sugary kefir modulates the succession and dominance of specific lactic acid bacteria. This study will provide valuable information for designing more sophisticated non-dairy fermented beverages with stable microbial properties.

Fecal Microflora from Dragonflies and Its Microorganisms Producing Carotenoids.

The intestines of insects are assumed to be the niche of various microbial groups, and a unique microflora could be formed under environmental conditions different from mammalian intestinal tracts. This chapter describes the bacterial flora formed in the intestines of two dragonfly species, "akatombo" (the red dragonfly; Sympetrum frequens) and "usubaki-tombo" (Pantala flavescens), which fly over a long distance, and carotenoid-producing microorganisms isolated from this flora. C30 carotenoids, which were produced by a bacterium Kurthia gibsonii isolated from S. frequens, were structurally determined.

Elucidation of the whole carotenoid biosynthetic pathway of aphids at the gene level and arthropodal food chain involving aphids and the red dragonfly.

BACKGROUND: Aphids can be positioned as robust pest insects in farming and as ones of the model organisms for arthropods in molecular biology. Carotenoids are pigments that protect organisms from photooxidative damage caused by excessive light. Aphids were shown to possess genes of fungal origin for carotenoid biosynthesis, whereas a little knowledge was available about the functions of the genes and the biosynthetic pathway. Even carotenoid species contained in aphids were not enough understood. Main purpose of this study is to clarify these insufficient findings. RESULTS: The whole carotenoid biosynthetic pathway of the pea aphid (Acyrthosiphon pisum) was elucidated at the gene level, through comprehensive functional analysis of its carotenogenic genes, using Escherichia coli that synthesized carotenoid substrates, along with structural and quantitative analysis of carotenoids from various aphid species. Four genes were needed to synthesize all carotenoids accumulated in aphids from geranylgeranyl diphosphate. The tor gene mediated desaturation reaction from phytoene to 3,4-didehydrolycopene. It was revealed that a gene designated ApCrtYB3, which was considered to have functionally evolved in aphids, can convert lycopene into uncommon carotenoids with the γ-ring such as (6'S)-ß,γ-carotene and γ,γ-carotene. We further demonstrated that the atypical carotenoids work as ecological indicators for estimating the food chain from aphids to predatory arthropods, and showed that aphids contributed with significant levels to the food chain from insect herbivores to several predatory arthropods, i.e., the red dragonfly (Sympetrum frequens; adults), seven-spotted ladybird (Coccinella septempunctata), and two spiders, Oxyopes sertatus and Nephila clavata. Gut microflora of the dragonfly (mature adults) was also found to include endosymbiotic bacteria such as Serratia symbiotica specific to the black bean aphid (Aphis fabae). CONCLUSIONS: We revealed the whole carotenoid biosynthetic pathway of aphids, including functional identification of the corresponding genes. Subsequently, we showed that arthropodal food chain can be estimated using the uncommon carotenoids of aphids as ecological indicators. This result indicated that aphids made significant contributions to the food chain of several predatory arthropods including the red-dragonfly adults. Aphids are likely to be positioned as an important "phytochemicals" source for some predatory insects and arachnids, which are often active under bright sunlight.

Chemical, Microbiological, and Functional Characterization of Kefir Produced from Cow's Milk and Soy Milk.

Kefir is a functional beverage that contains lactic and acetic acid bacteria (LAB, AAB) and yeasts. This work's aim was to study the chemical, microbial, and functional characteristics of kefir produced from cow's milk and soy milk. After fermentation, free amino acids were 20.92 mg 100 mL-1 and 36.20 mg 100 mL-1 for cow's milk and soy milk kefir, respectively. Glutamic acid was majority in both, suggesting that microbial proteolysis leads to an increase in free amino acids including glutamic acid. 108-109 CFU mL-1 LAB, 106-107 CFU mL-1 AAB, and 106-107 CFU mL-1 yeasts were counted in cow's milk kefir, whereas soy milk kefir contained greatly lower yeasts and AAB. Lactococcus lactis, Kazachstania unispora, and Saccharomyces cerevisiae were isolated as major microorganisms in both kefirs. Acetobacter orientalis only existed in cow's milk kefir. Cow's milk and soy milk showed ACE inhibitory activity, which significantly increased after fermentation. Both kefirs also exhibited antioxidant activity and bactericidal activity against Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus.

Development of a new chromogenic method for putrescine quantification using coupling reactions involving putrescine oxidase.

Quantification of polyamines, including putrescine, is generally performed using high-performance liquid chromatography (HPLC) or gas chromatography. However, these methods are time-consuming because of sample derivatization and analytical reagent preparation. In this study, we developed a simple and high-throughput putrescine quantification method on a 96-well microtiter plate using putrescine oxidase from Rhodococcus erythropolis NCIMB 11540, peroxidase, 4-aminoantipyrine, and N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt. The developed method (named as PuO-POD-4AA-TOPS method) was applicable to bacterial culture supernatants. Furthermore, putrescine concentrations determined by the developed method roughly corresponded to the concentrations determined by HPLC.

In vivo hepatic clearance of lipophilic drugs predicted by in vitro uptake data into cryopreserved hepatocytes suspended in sera of rats, guinea pigs, monkeys and humans.

Evaluation of uptake of lipophilic acid compounds into hepatocytes was an unresolved drug development issue because of their adsorption to cells and materials and low analytical sensitivity and accuracy in assessment of protein bindings. Uptake assays of compounds using hepatocytes suspended in serum were expected to solve these problems for prediction of in vivo hepatic clearance. Here, for compounds with high protein binding (>99%), diflunisal, montelukast, cerivastatin, telmisartan, fluvastatin and six new drug candidates, in vivo hepatic clearance predicted based on hepatic depletion and uptake (CLh, uptake, predicted) data using hepatocytes in the absence and presence of sera was investigated. In vitro hepatic uptake results with hepatocytes suspended in serum improved prediction of human hepatic clearance values for highly lipophilic montelukast and telmisartan. In vivo CLh, uptake, predicted values of six new highly lipophilic acid drug candidates (protein binding >99.97%) and diflunisal, montelukast and cerivastatin predicted based on hepatocytes suspended in serum were within threefold differences of their total clearance in vivo in rats, guinea pigs or monkeys, except for montelukast in monkeys (5.8-fold). These results suggest that the human hepatic uptake in hepatocytes suspended in serum is useful for prediction of CLh, uptake, predicted, especially for highly lipophilic/protein binding acid compounds.

Robust Domination of Lactobacillus sakei in Microbiota During Traditional Japanese Sake Starter Yamahai-Moto Fermentation and the Accompanying Changes in Metabolites.

The successful production of sake (Japanese rice wine) is brought about by drastic changes in microbial flora and chemical components during fermentation. In the traditional manufacturing process of sake starter (yamahai-moto), spontaneous growth of lactic acid bacteria suppresses inappropriate microorganisms and prepares the optimum environment for the alcohol fermentative yeast. In this study, we analyzed the changes in bacterial flora and chemical components of yamahai-moto. High-throughput next-generation sequencing (NGS) of the 16S ribosomal RNA gene V4 region revealed that various kinds of bacteria, including nitrate-reducing bacteria, existed in the early fermentation stage; however, Lactobacillus sakei then increased drastically to become dominant in the middle stage. Interestingly, this result was different from that obtained in the previous year at the same manufacturer; the early-stage major bacterium was Lactobacillus acidipiscis. Lactic acid, glucose, isomaltose, and total free amino acids increased throughout the fermentation process, which was attributable to the metabolism of L. sakei and the koji mold. It is noteworthy that significant ornithine accumulation and arginine consumption were observed from the middle to late stages. Thirty-eight percent of the L. sakei isolates from yamahai-moto exhibited significant ornithine production, indicating that the arginine deiminase pathway of L. sakei was working to survive the extremely low pH environment of the moto after the middle stage. This is the first report that includes concurrent analyses of the NGS-based bacterial flora and chemical components of yamahai-moto, providing further knowledge to help understand and improve the process of sake brewing.

Structural and functional analysis of the carotenoid biosynthesis genes of a Pseudomonas strain isolated from the excrement of Autumn Darter.

There are many reports about carotenoid-producing bacteria and carotenoid biosynthesis genes. In databases for Pseudomonas genome sequences, there are genes homologous to carotenoid biosynthesis genes, but the function of these genes in Pseudomonas has not been elucidated. In this study, we cloned the carotenoid biosynthesis genes from a Pseudomonas sp. strain, named Akiakane, which was isolated from the excrement of the Autumn Darter dragonfly. Using an Escherichia coli functional expression system, we confirmed that the idi, crtE, crtB, crtI, and crtY gene products of the Akiakane strain show predictable catalytic activities. A cluster of six genes was also found, which was comparable to other carotenoid-producing bacteria that belong to the α-Proteobacteria or γ-Proteobacteria class.

Characterization of two cryptic plasmids from Kocuria palustris IPUFS-1 and construction of novel Escherichia coli-Kocuria shuttle vector for biocatalysis.

Two cryptic plasmids, designated pKPAL1 and pKPAL2, were identified from the gram-positive bacterium Kocuria palustris IPUFS-1, which was isolated from a fish source. The 2251-bp and 2488-bp circular genomes of pKPAL1 and pKPAL2, respectively, were sequenced. Subsequent open reading frame (ORF) and homology search analyses suggested that pKPAL1 and pKPAL2 possess two and three ORFs, respectively, and encode the putative replication proteins, RepA and RepB, like the genomes of several plasmids in gram-positive bacteria. Thus, pKPAL1 and pKPAL2 were inferred to belong to the ColE2 plasmid family. We constructed novel Escherichia coli-Kocuria shuttle vectors pKITE101-103 based on pKPAL1. The constructed shuttle vector was stably maintained in Kocuria transformant cells, and vector copy number was estimated to be about 60 per cell. Leifsonia sp. S749 alcohol dehydrogenase (LSADH) was efficiently expressed in Kocuria rhizophila DC2201 using the pKITE103P vector under the control of the promoter of glyceraldehyde 3-phosphate dehydrogenase (gapdh). Herein, we demonstrate that the novel shuttle vector is a useful tool for developing biocatalysts based on organic solvent-tolerant Kocuria cells.

Laboratory-scale production of (S)-reticuline, an important intermediate of benzylisoquinoline alkaloids, using a bacterial-based method.

Benzylisoquinoline alkaloids (BIAs) are a group of plant secondary metabolites that have been identified as targets for drug discovery because of their diverse pharmaceutical activities. Well-known BIAs are relatively abundant in plants and have therefore been extensively studied. However, although unknown BIAs are also thought to have valuable activities, they are difficult to obtain because the raw materials are present at low abundance in nature. We have previously reported the fermentative production of an important intermediate (S)-reticuline from dopamine using Escherichia coli. However, the yield is typically limited. Here, we improved production efficiency by combining in vivo tetrahydropapaveroline production in E. coli with in vitro enzymatic synthesis of (S)-reticuline. Finally, 593 mg of pure (S)-reticuline was obtained from 1 L of the reaction mixture. Because this bacterial-based method is simple, it could be widely used for production of (S)-reticuline and related BIAs, thereby facilitating studies of BIAs for drug discovery.

Total biosynthesis of opiates by stepwise fermentation using engineered Escherichia coli.

Opiates such as morphine and codeine are mainly obtained by extraction from opium poppies. Fermentative opiate production in microbes has also been investigated, and complete biosynthesis of opiates from a simple carbon source has recently been accomplished in yeast. Here we demonstrate that Escherichia coli serves as an efficient, robust and flexible platform for total opiate synthesis. Thebaine, the most important raw material in opioid preparations, is produced by stepwise culture of four engineered strains at yields of 2.1 mg l(-1) from glycerol, corresponding to a 300-fold increase from recently developed yeast systems. This improvement is presumably due to strong activity of enzymes related to thebaine synthesis from (R)-reticuline in E. coli. Furthermore, by adding two genes to the thebaine production system, we demonstrate the biosynthesis of hydrocodone, a clinically important opioid. Improvements in opiate production in this E. coli system represent a major step towards the development of alternative opiate production systems.

Tracing microbiota changes in yamahai-moto, the traditional Japanese sake starter.

Sake is made from steamed rice, malted rice, and water. Sake production begins with the preparation of a small-scale starter (moto); the quality of moto significantly influences the flavor and richness of sake. In the traditional starter, yamahai-moto, the growth of naturally occurring lactic acid bacteria represses the putrefactive micro-organisms, whereas in the modern starter, sokujo-moto, this is achieved by adding lactic acid. In this study, the successive change in bacterial flora of yamahai-moto was analyzed by pyrosequencing 16S ribosomal RNA genes. Lactobacillus was dominant throughout the process (93-98%). Nitrate-reducing bacteria that have been generally assumed to be the first colonizers of yamahai-moto were scarcely found in the early stage, but Lactobacillus acidipiscis dominated. Lactobacillus sakei drastically increased in the middle stage. This is the first report, though one case study, to show how the early stage microbiota in Japanese yamahai-moto is varyingly controlled without nitrate-reducing bacteria using next-generation sequencing.

The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides.

Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi, narezushi, konkazuke, and ishiru. Various kinds of lactic acid bacteria (LAB) are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA) sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE) inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA) concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v) glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates), Lactobacillus brevis (6 isolates), and Weissella hellenica (2 isolates) had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates), L. buchneri (2 isolates), and W. hellenica (2 isolates) was stronger than that of all whey cultured with soy protein media, and these IC50 were < 1 mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.