Simultaneous removal of aliphatic and aromatic crude oil hydrocarbons by Pantoea agglomerans isolated from petroleum-contaminated soil in the west of Iran.

Hydrocarbons are considered as one of the most common and harmful environmental pollutants affecting human health and the environment. Bioremediation as an environmentally friendly, highly efficient, and cost-effective method in remediating oil-contaminated environments has been interesting in recent decades. In this study, hydrocarbon degrader bacterial strains were isolated from the highly petroleum-contaminated soils in the Dehloran oil field in the west of Iran. Out of 37 isolates, 15 can grow on M9 agar medium that contains 1.5 g L-1 of crude oil as the sole carbon source. The morphological, biochemical, and 16SrRNA sequencing analyses were performed for the isolates. The choosing of the isolates as the hydrocarbon degrader was examined by evaluating the efficacy of their crude oil removal at a concentration of 10 g L-1 in an aqueous medium. The results showed that five isolates belonging to Pseudomonas sp., Pseudomonas oryzihabitans, Roseomonas aestuarii, Pantoea agglomerans, and Arthrobacter sp. had a hyper hydrocarbon-degrading activity and they could remove more than 85% of the total petroleum hydrocarbon (TPH) after 96 h. The highest TPH removal of about 95.75% and biodegradation rate of 0.0997 g L-1 h-1 was observed for P. agglomerans. The gas chromatography-mass spectroscopy (GC-MS) analysis was performed during the biodegradation process by P. agglomerans to detect the degradation intermediates and final products. The results confirmed the presence of intermediates such as alcohols and fatty acids in the terminal oxidation pathway of alkanes in this biodegradation process. A promising P. agglomerans NB391 strain can remove aliphatic and aromatic hydrocarbons simultaneously.

Pantoea jilinensis D25 enhances tomato salt tolerance via altering antioxidant responses and soil microbial community structure.

As a major challenge to global food security, soil salinity is an important abiotic stress factor that seriously affects the crop growth and yield. In this study, the mechanism of salt resistance of Pantoea jilinensis D25 and its improving effect on salt tolerance of tomato were explored with salt resistance-related genes identified in strain D25 by genomic sequencing. The results showed that in comparison with the treatment of NaCl, strain D25 significantly increased the fresh weight, shoot length, root length, and chlorophyll content of tomato under salt stress by 46.7%, 20%, 42.4%, and 44.2%, respectively, with increased absorptions of various macronutrients and micronutrients and decreased accumulation of Na+. The activities of defense enzymes (peroxidase, catalase, superoxide dismutase, phenylalanine ammonia-lyase, and polyphenol oxidase) were enhanced, while the content of malondialdehyde was decreased. The results of quantitative real-time PCR analysis showed that the expressions of genes (SlSOS1, SlNHX1, SlHKT1.1, SlSOD1, SlAPX2, SlAOS, SlPin II, Solyc08g066270.1, Solyc03g083420.2 and SlGA20ox1) related to ion transporters, antioxidant machinery, key defense, serine/threonine protein kinase synthesis, and gibberellin (GA) signal protein were up-regulated and were the highest in the treatment of both NaCl and strain D25. The activities of enzymes (dehydrogenase, urease, invertase, and catalase activities) related to soil fertility were enhanced. The results of 16S rRNA sequencing showed that soil microbial diversity and the abundance of probiotics (e.g., Acidibacter, Limnobacter, and Romboutsia) were significantly increased. Our study provided strong experimental evidence to support the agricultural application of strain D25 in the promotion of growth in crops.

Beneficial impact of cathelicidin on hypersensitivity pneumonitis treatment-In vivo studies.

Cathelicidin (CRAMP) is a defence peptide with a wide range of biological responses including antimicrobial, immunomodulatory and wound healing. Due to its original properties the usefulness of CRAMP in the treatment of pulmonary fibrosis was assessed in a murine model of hypersensitivity pneumonitis (HP). The studies were conducted on mouse strain C57BL/6J exposed to a saline extract of Pantoea agglomerans cells (HP inducer). Cathelicidin was administered in the form of an aerosol during and after HP development. Changes in the composition of immune cell populations (NK cells, macrophages, lymphocytes: Tc, Th, Treg, B), were monitored in lung tissue by flow cytometry. Extracellular matrix deposition (collagens, hydroxyproline), the concentration of cytokines involved in inflammatory and the fibrosis process (IFNγ, TNFα, TGFß1, IL1ß, IL4, IL5, IL10, IL12α, IL13) were examined in lung homogenates by the ELISA method. Alterations in lung tissue morphology were examined in mouse lung sections stained with haematoxylin and eosin as well as Masson trichrome dyes. The performed studies revealed that cathelicidin did not cause any negative changes in lung morphology/structure, immune cell composition or cytokines production. At the same time, CRAMP attenuated the immune reaction induced by mice chronic exposure to P. agglomerans and inhibited hydroxyproline and collagen deposition in the lung tissue of mice treated with bacteria extract. The beneficial effect of CRAMP on HP treatment was associated with restoring the balance in quantity of immune cells, cytokines production and synthesis of extracellular matrix components. The presented study suggests the usefulness of cathelicidin in preventing lung fibrosis; however, cathelicidin was not able to reverse pathological changes completely.

Bioactive Levan-Type Exopolysaccharide Produced by Pantoea agglomerans ZMR7: Characterization and Optimization for Enhanced Production.

Levan is an industrially important, functional biopolymer with considerable applications in the food and pharmaceutical fields owing to its safety and biocompatibility. Here, levan-type exopolysaccharide produced by Pantoea agglomerans ZMR7 was purified by cold ethanol precipitation and characterized using TLC, FTIR, 1H, and 13C NMR spectroscopy. The maximum production of levan (28.4 g/l) was achieved when sucrose and ammonium chloride were used as carbon and nitrogen sources, respectively, at 35°C and an initial pH of 8.0. Some biomedical applications of levan like antitumor, antiparasitic, and antioxidant activities were investigated in vitro. The results revealed the ability of levan at different concentrations to decrease the viability of rhabdomyosarcoma and breast cancer cells compared with untreated cancer cells. Levan appeared also to have high antiparasitic activity against the promastigote of Leishmania tropica. Furthermore, levan had strong DPPH radical scavenging (antioxidant) activity. These findings suggest that levan produced by P. agglomerans ZMR7 can serve as a natural biopolymer candidate for the pharmaceutical and medical fields.

Isolation and characterization of bacteria from activated sludge capable of degrading 17α-ethinylestradiol, a contaminant of high environmental concern.

The compound 17α-ethinylestradiol (EE2) is a synthetic oestrogen which is classified as a group 1 carcinogen by the World Health Organization. Together with other endocrine disruptor compounds, EE2 has been included in the surface water Watch List by the European Commission, since it causes severe adverse effects in ecosystems. Thus, it became a high priority to find or improve processes such as biodegradation of EE2 to completely remove this drug from the wastewater treatment plants (WWTPs). The present study aimed at the isolation of bacteria capable of degrading EE2 using environmental samples, namely a sludge from the Faro Northwest WWTP. Four isolates with ability to grow in the presence of 50 mg l-1 EE2 were obtained. The analysis of 16SrRNA gene sequences identified the isolated bacteria as Acinetobacter bouvetii, Acinetobacter kookii, Pantoea agglomerans and Shinella zoogloeoides. The results of biodegradation assays showed that Acinetobacter bouvetii, Acinetobacter kookii, Pantoea agglomerans and Shinella zoogloeoides were able to degrade 47±4 %, 55±3 %, 64±4% and 35±4 %, respectively of 13 mg l-1 EE2 after 168 h at 28 °C. To the best of our knowledge, these bacterial isolates were identified as EE2 degraders for the first time. In a preliminary experiment on the identification of metabolic products resulting from EE2 degradation products such as estrone (E1), γ-lactone compounds, 2-pentanedioic acid and 2-butenedioic acid an intermediate metabolite of the TCA cycle, were detected.

A Phosphonate Natural Product Made by Pantoea ananatis is Necessary and Sufficient for the Hallmark Lesions of Onion Center Rot.

Pantoea ananatis is the primary cause of onion center rot. Genetic data suggest that a phosphonic acid natural product is required for pathogenesis; however, the nature of the molecule is unknown. Here, we show that P. ananatis produces at least three phosphonates, two of which were purified and structurally characterized. The first, designated pantaphos, was shown to be 2-(hydroxy[phosphono]methyl)maleate; the second, a probable biosynthetic precursor, was shown to be 2-(phosphonomethyl)maleate. Purified pantaphos is both necessary and sufficient for the hallmark lesions of onion center rot. Moreover, when tested against mustard seedlings, the phytotoxic activity of pantaphos was comparable to the widely used herbicides glyphosate and phosphinothricin. Pantaphos was also active against a variety of human cell lines but was significantly more toxic to glioblastoma cells. Pantaphos showed little activity when tested against a variety of bacteria and fungi.IMPORTANCEPantoea ananatis is a significant plant pathogen that targets a number of important crops, a problem that is compounded by the absence of effective treatments to prevent its spread. Our identification of pantaphos as the key virulence factor in onion center rot suggests a variety of approaches that could be employed to address this significant plant disease. Moreover, the general phytotoxicity of the molecule suggests that it could be developed into an effective herbicide to counter the alarming rise in herbicide-resistant weeds.

Secondary metabolites produced by endophytic Pantoea ananatis derived from roots of Baccharoides anthelmintica and their effect on melanin synthesis in murine B16 cells.

Five indole derivatives, 1H-indol-7-ol (1), tryptophol (2), 3-indolepropionic acid (3), tryptophan (4), 3,3-di(1H-indol-3-yl)propane-1,2-diol (5) and two diketopiperazines, cyclo(L-Pro-L-Tyr) (6), cyclo[L-(4-hydroxyprolinyl)-L-leucine (7) along with one dihydrocinnamic acid (8) were isolated from Pantoea ananatis VERA8, that endophytic bacteria derived from Baccharoides anthelmintica roots. This is a first report towards an isolation of endophytic strains (funji or bacteria) from the B. anthelmintica herb. The synergetic properties of the total extract compositions, as well as effects of the pure isolated secondary metabolites evaluated on their melanin synthesis in murine B16 cells towards for vitiligo treatment.

Effects of feeding a Lactobacillus plantarum JL01 diet on caecal bacteria and metabolites of weaned piglets.

Currently, knowledge is limited concerning the impact of a Lactobacillus plantarum JL01 diet for weaned piglets on caecal bacteria and metabolite profiles. In our experiments, 24 weaned piglets were randomly divided into two groups; each piglet in the treatment groups (Cec-Lac) was fed a basic diet and administered 10 ml of L. plantarum JL01 (1·0 × 109  CFU per ml) every day. The control group (Cec-Con) was fed a basic diet. After feeding for 28 days, we analysed the parameters of the caecal digesta of weaned piglets. We used 16S rDNA gene sequencing and mass spectrometry (MS)-based metabolomics techniques to investigate the effect of a L. plantarum JL01 diet on intestinal microbial composition and its metabolite profiles in the caecum contents of weaned piglets. The results showed that the richness estimators (ACE and Chao indices) in the caecal bacteria increased in the Cec-Lac group. Prevotella_2 and Desulfovibrio decreased significantly, while Pantoea and Rectale_group increased in the caecum of weaned piglets in the Cec-Lac group. Furthermore, Pearson's correlation analysis revealed that the genus Rectale_group was positively correlated with indole-3-acetic acid (P < 0·05), and the genus Pantoea had the same correlation with 1-palmitoyl lysophosphatidic acid. The metabolomics analysis revealed that the L. plantarum JL01 diet supplementation had significant effects on tryptophan metabolism and fat digestion and absorption. The results indicated that the L. plantarum JL01 dietary supplementation not only altered the microbial composition but also mediated tryptophan metabolism and fat digestion and absorption in the caecum, factors that may further affect the health of the host.

Enhanced Effect of Hyaluronan and Elastin Synthesis in Fibroblasts Through Lipopolysaccharide-activated Macrophages.

BACKGROUND/AIM: The functions of macrophages change in response to environmental factors such as lipopolysaccharide (LPS). LPS derived from Pantoea agglomerans (LPSp) is involved in macrophage activation and tissue repair when administered dermally. LPSp-activated macrophages may be useful for restoring and maintaining homeostasis of the skin. MATERIALS AND METHODS: Phorbol myristate acetate-treated human monocytes (THP-1 cells) were activated with LPSp. The medium of LPSp-activated THP-1 cells was added to normal human dermal fibroblasts (NHDF cells). After 24 h, the expression of hyaluronan (HA) synthase (HAS)2, hyaluronidase (HYAL)1, and tropoelastin in NHDF cells was analyzed using quantitative real-time PCR. RESULTS: The expression of HAS2 and tropoelastin was significantly increased, but that of HYAL1 was significantly decreased. It was demonstrated that the abilities of HA and elastin synthesis in NHDF cells increased through LPSp-activated THP-1 cells. CONCLUSION: LPSp-activated macrophages may be useful for enhancing the abilities of HA and elastin synthesis in fibroblasts, subsequently improving dysfunction and reducing various age-related disorders.

A broad-spectrum antibacterial natural product from the cystic fibrosis isolate, Pantoea agglomerans Tx10.

The prevalence of antibiotic-resistant Gram-positive and Gram-negative pathogens has prompted considerable efforts to identify new antibacterials. Here we show that Pantoea agglomerans Tx10-an isolate from the sputum sample of a cystic fibrosis patient-is a strong competitor that inhibits the growth of a wide range of Gram-positive and Gram-negative bacteria through the production of a secreted compound. A genetic screen to identify the genes involved in the production of this compound resulted in the delineation of a 6-gene biosynthetic cluster. We called this compound Pantoea Natural Product 2 (PNP-2). Assays with mutants deficient in PNP-2 production revealed they were still able to inhibit Erwinia amylovora, suggesting the production of a second antibiotic, which we identified as Pantocin A. We generated Pantocin A knockouts, and a PNP-2/Pantocin A double knockout and used these to evaluate the spectrum of activity of both natural products. We show that strains of Enterobacter, E. coli, Klebsiella, Kosakonia, Pseudocitrobacter, Salmonella, Staphylococcus, and Streptococcus as well as the majority of Pantoea strains assayed are susceptible to PNP-2, indicating a broad spectrum of activity, and potential for therapeutic development.

Identification and Characterization of pantocin wh-1, a Novel Cyclic Polypeptide Produced by Pantoea dispersa W18.

Pantoea dispersa W18, isolated from contaminated soil, was found to exert antimicrobial activity against Mycobacterium species, including Mycobacterium tuberculosis, an important human pathogen. Here, the anti-mycobacterial compound produced by Pantoea dispersa W18 was purified by a combination of hydrophobic interaction chromatography, cation exchange chromatography, and reverse phase HPLC. Active compounds from Pantoea dispersa W18 were identified as a natural peptide named pantocin wh-1 with a 1927 Da molecular weight. The primary structure of this compound was detected by N-terminal amino acid sequencing. The amino acid sequence of pantocin wh-1 consisted of 16 amino acid residues with a cyclic structure. The pantocin wh-1 could be inactivated by protease K, but was heat stable and unaffected by pH (2-12). However, the activity was not completely inactivated by trypsin and pepsin. This is the first report of a cyclic polypeptide purified from a strain of Pantoea dispersa.

An roGFP2-Based Bacterial Bioreporter for Redox Sensing of Plant Surfaces.

The reduction-oxidation (redox) environment of the phytobiome (i.e., the plant-microbe interface) can strongly influence the outcome of the interaction between microbial pathogens, commensals, and their host. We describe a noninvasive method using a bacterial bioreporter that responds to reactive oxygen species and redox-active chemicals to compare microenvironments perceived by microbes during their initial encounter of the plant surface. A redox-sensitive variant of green fluorescent protein (roGFP2), responsive to changes in intracellular levels of reduced and oxidized glutathione, was expressed under the constitutive SP6 and fruR promoters in the epiphytic bacterium Pantoea eucalypti 299R (Pe299R/roGFP2). Analyses of Pe299R/roGFP2 cells by ratiometric fluorometry showed concentration-dependent responses to several redox active chemicals, including hydrogen peroxide (H2O2), dithiothreitol (DTT), and menadione. Changes in intracellular redox were detected within 5 min of addition of the chemical to Pe299R/roGFP2 cells, with approximate detection limits of 25 and 6 µM for oxidation by H2O2 and menadione, respectively, and 10 µM for reduction by DTT. Caffeic acid, chlorogenic acid, and ascorbic acid mitigated the H2O2-induced oxidation of the roGFP2 bioreporter. Aqueous washes of peach and rose flower petals from young blossoms created a lower redox state in the roGFP2 bioreporter than washes from fully mature blossoms. The bioreporter also detected differences in surface washes from peach fruit at different stages of maturity and between wounded and nonwounded sites. The Pe299R/roGFP2 reporter rapidly assesses differences in redox microenvironments and provides a noninvasive tool that may complement traditional redox-sensitive chromophores and chemical analyses of cell extracts.

Bacteria-assisted biogreen synthesis of radical scavenging exopolysaccharide-iron complexes: an oral nano-sized nutritional supplement with high in vivo compatibility.

Microbial exopolysaccharides (EPSs) have recently served as an efficient substrate for the production of biocompatible metal nanoparticles (NPs) given their favorable stabilizing and reducing properties due to the presence of polyanionic functional groups in their structure. In the present work, Pantoea sp. BCCS 001 GH was used to produce EPS-stabilized biogenic Fe NPs as a complex through a novel biosynthesis reaction. Physicochemical characterization of the EPS-Fe complex was performed, indicating high thermal stability, desirable magnetic properties due to the uniform distribution of the Fe NPs with the average size of ∼10 nm and spherical shape within the EPS matrix. In addition, the in vivo toxicity of the EPS-stabilized Fe NPs was evaluated to investigate their potential for the treatment of iron deficiency anemia. Biological blood parameters and organ histology studies confirmed very high safety of the biosynthesized composite, making EPS-Fe a suitable candidate with an economical and environment friendly synthesis method for a wide spectrum of potential fields in medicine.

Two Pantoea agglomerans type III effectors can transform nonpathogenic and phytopathogenic bacteria into host-specific gall-forming pathogens.

Pantoea agglomerans (Pa), a widespread commensal bacterium, has evolved into a host-specific gall-forming pathogen on gypsophila and beet by acquiring a plasmid harbouring a type III secretion system (T3SS) and effectors (T3Es). Pantoea agglomerans pv. gypsophilae (Pag) elicits galls on gypsophila and a hypersensitive response on beet, whereas P. agglomerans pv. betae (Pab) elicits galls on beet and gypsophila. HsvG and HsvB are two paralogous T3Es present in both pathovars and act as host-specific transcription activators on gypsophila and beet, respectively. PthG and PseB are major T3Es that contribute to gall development of Pag and Pab, respectively. To establish the minimal combinations of T3Es that are sufficient to elicit gall symptoms, strains of the nonpathogenic bacteria Pseudomonas fluorescens 55, Pa 3-1, Pa 98 and Escherichia coli, transformed with pHIR11 harbouring a T3SS, and the phytopathogenic bacteria Erwinia amylovora, Dickeya solani and Xanthomonas campestris pv. campestris were transformed with the T3Es hsvG, hsvB, pthG and pseB, either individually or in pairs, and used to infect gypsophila and beet. Strikingly, all the tested nonpathogenic and phytopathogenic bacterial strains harbouring hsvG and pthG incited galls on gypsophila, whereas strains harbouring hsvB and pseB, with the exception of E. coli, incited galls on beet.

Pantocin A, a peptide-derived antibiotic involved in biological control by plant-associated Pantoea species.

The genus Pantoea contains a broad range of plant-associated bacteria, including some economically important plant pathogens as well as some beneficial members effective as biological control agents of plant pathogens. The most well-characterized representatives of biological control agents from this genus generally produce one or more antimicrobial compounds adding to biocontrol efficacy. Some Pantoea species evaluated as biocontrol agents for fire blight disease of apple and pear produce a histidine-reversible antibiotic. Three commonly studied histidine-reversible antibiotics produced by Pantoea spp. are herbicolin O, MccEh252, and pantocin A. Pantocin A is a novel ribosomally encoded and post-translationally modified peptide natural product. Here, we review the current knowledge on the chemistry, genetics, biosynthesis, and incidence and environmental relevance of pantocin A and related histidine-reversible antibiotics produced by Pantoea.

Priming with ACC-utilizing bacterium attenuated copper toxicity, improved oxidative stress tolerance, and increased phytoextraction capacity in wheat.

The major challenges for the plants growing in metal-contaminated soils are deficiency of nutrients, biomass reduction, and severe oxidative damages in the presence of heavy metals. In this regard, our aim was to overcome these challenges through the use of efficient microbial strains in metal-polluted soils and to assess its/their physiological and biochemical effects. In the current study, a copper (Cu)-resistant bacterium was isolated from the rhizospheric soil of 'Ziziphus nummularia' and evaluated for its ability to promote the wheat growth under the gradient stress of copper. Based on 16S rRNA gene sequencing, the isolate was identified as Pantoea sp. Among the plant growth promoting tests, the isolate showed the production of indole acetic acid, solubilization of inorganic phosphate, and ACC deaminase activity. Also, the isolate showed resistance to many heavy metals and antibiotics and increased the water-soluble copper in solution. The results of pot studies showed that bacterial application promoted various growth parameters of wheat plants and also enhanced the Cu uptake of wheat from the Cu-amended soil. The results showed that enhancement of Cu stress (100 to 300 mg kg-1) resulted in a decrease in various compatible solutes such as proline, total soluble sugars, and total protein content, and increase in the level of malondialdehyde (MDA), latter of which is the indicator of oxidative stress. Bacterial treatment markedly increased the proline, soluble sugar, total protein content, and decreased the MDA content under Cu stress. In addition, bacterial inoculation significantly alleviated the harmful effect of metal toxicity by decreasing the activation of ROS molecules including superoxide (O2-) and hydrogen peroxide (H2O2). The activation of various antioxidative enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) was noted following bacterial inoculation under Cu stress. Therefore, the present study demonstrates the potential of the isolate Pantoea sp. ZNP-5 to improve the growth and phytoextraction of metal from the metal-polluted soil through the polyphasic mechanism of action.

Center Rot of Onion (Allium cepa) Caused by Pantoea ananatis Requires pepM, a Predicted Phosphonate-Related Gene.

Pantoea ananatis, a cause of center rot of onion, is problematic in the United States and elsewhere. The bacterium lacks disease determinants common to most other bacterial pathogens of plants. A genomic island containing the gene pepM was detected within many onion-pathogenic strains of P. ananatis of diverse origins. The pepM gene of P. ananatis putatively encodes a protein that converts phosphoenolpyruvate to phosphonopyruvate, the first step in the biosynthesis of phosphonates and related molecules. This gene appears to be essential for center rot disease. Deletion of pepM rendered the mutant strain unable to cause lesions in leaves of growing onions and water-soaking of inoculated yellow onion bulbs. Furthermore, growth of the deletion mutant in onion leaves was significantly diminished compared with wild-type bacteria, and the mutant failed to cause cell death in tobacco. Complementation of the mutated strain with pepM restored the phenotype to wild-type capability. The pepM gene is the first pathogenicity factor identified that affects bacterial fitness as well as symptom development in both leaves and bulbs in a pathogen causing center rot of onion.

Oral administration of Pantoea agglomerans-derived lipopolysaccharide prevents development of atherosclerosis in high-fat diet-fed apoE-deficient mice via ameliorating hyperlipidemia, pro-inflammatory mediators and oxidative responses.

Pantoea agglomerans (P. agglomerans) is a Gram-negative bacterium that grows symbiotically with various edible plants, and the oral or sublingual administration of lipopolysaccharide derived from P. agglomerans (LPSp) have been suggested to contribute to prevention of immune-related diseases. Our previous study indicated that orally administered LPSp was shown to exhibit an LDL-lowering effect in hyperlipidemic volunteers; however, a preventive effect of LPSp on atherosclerosis is unclear. The present study attempted to evaluate the anti-atherosclerotic effect by LPSp in a mouse model of high-fat diet (HFD)-induced atherosclerosis. For 16 weeks, apoE-deficient mice were fed an HFD and received drinking water containing LPSp (0.3 or 1 mg/kg body weight/day). The results showed that the orally administered LPSp decreased body weight. A significant reduction in atherosclerotic plaque deposition was observed even with the lower dose of LPSp. The biochemical analyses showed that LPSp markedly improved glucose tolerance and reduced plasma LDL and oxidized LDL levels. In addition, LPSp significantly reduced the production of pro-inflammatory mediators including MCP-1 (in the plasma), TNF-α and IL-6 (in the colon), and decreased the oxidative burst activities in the peripheral blood sample. Taken together, these results suggest the possibility that oral administration of LPSp can effectively ameliorate HFD-induced hyperlipidemia and inflammatory/oxidative responses to prevent atherosclerosis and related metabolic disorders.

Lipopolysaccharides Derived from Pantoea agglomerans Can Promote the Phagocytic Activity of Amyloid ß in Mouse Microglial Cells.

BACKGROUND/AIM: Recent studies reported that lipopolysaccharide (LPS) exhibits beneficial effects on prevention of immune-related diseases by activating macrophages. We previously demonstrated that pre-treatment with LPS derived from Pantoea agglomerans (LPSp) activated amyloid ß (Aß) phagocytosis in mouse primary microglia. In the present study, we further examined the promotory effect on phagocytosis of phagocytic particles in the C8-B4 microglia cell line. MATERIALS AND METHODS: Phagocytic analysis of C8-B4 cells was evaluated using phagocytic particles (latex beads or HiLyte™ Fluor 488-conjugated Aß1-42). RESULTS: The phagocytic activity of latex beads was dependent on the concentration of beads and incubation time. LPSp, at as low as 100 pg/ml, significantly increased phagocytosis against the beads. In the experiment of Aß1-42 phagocytosis, LPSp significantly increased Aß phagocytic activity. CONCLUSION: LPSp treatment was confirmed to enhance Aß1-42 phagocytosis by mouse microglia. It is suggested that the use of LPSp may be a potential promising candidate for the prevention of Alzheimer's disease.

Fermentative Production of Cysteine by Pantoea ananatis.

Cysteine is a commercially important amino acid; however, it lacks an efficient fermentative production method. Due to its cytotoxicity, intracellular cysteine levels are stringently controlled via several regulatory modes. Managing its toxic effects as well as understanding and deregulating the complexities of regulation are crucial for establishing the fermentative production of cysteine. The regulatory modes include feedback inhibition of key metabolic enzymes, degradation, efflux pumps, and the transcriptional regulation of biosynthetic genes by a master cysteine regulator, CysB. These processes have been extensively studied using Escherichia coli for overproducing cysteine by fermentation. In this study, we genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to identify key factors required for cysteine production. According to this and our previous studies, we identified a major cysteine desulfhydrase gene, ccdA (formerly PAJ_0331), involved in cysteine degradation, and the cysteine efflux pump genes cefA and cefB (formerly PAJ_3026 and PAJ_p0018, respectively), which may be responsible for downregulating the intracellular cysteine level. Our findings revealed that ccdA deletion and cefA and cefB overexpression are crucial factors for establishing fermentative cysteine production in P. ananatis and for obtaining a higher cysteine yield when combined with genes in the cysteine biosynthetic pathway. To our knowledge, this is the first demonstration of cysteine production in P. ananatis, which has fundamental implications for establishing overproduction in this microbe.IMPORTANCE The efficient production of cysteine is a major challenge in the amino acid fermentation industry. In this study, we identified cysteine efflux pumps and degradation pathways as essential elements and genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to establish the fermentative production of cysteine. This study provides crucial insights into the design and construction of cysteine-producing strains, which may play central roles in realizing commercial basis production.