Journal of Microbiology

Volume 52(12); December 2014

Review

Minireivew] Protective Role of Gut Commensal Microbes against Intestinal Infections: My Young Yoon , Keehoon Lee , Sang Sun Yoon; J. Microbiol. 2014;52(12):983-989. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4655-2

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39 Citations

Abstract: The human gastrointestinal tract is colonized by multitudes of microorganisms that exert beneficial effects on human health. Mounting evidence suggests that intestinal microbiota contributes to host resistance against enteropathogenic bacterial infection. However, molecular details that account for such an important role has just begun to be understood. The commensal microbes in the intestine regulate gut homeostasis through activating the development of host innate immunity and producing molecules with antimicrobial activities that directly inhibit propagation of pathogenic bacteria. Understanding the protective roles of gut microbiota will provide a better insight into the molecular basis that underlies complicated interaction among host-pathogen-symbiont. In this review, we highlighted recent findings that help us broaden our knowledge of the intestinal ecosystem and thereby come up with a better strategy for combating enteropathogenic infection.

Journal Article

Nocardioides paucivorans sp. nov. Isolated from Soil: Jae-Hyung Ahn , Jun-Muk Lim , Soo-Jin Kim , Jaekyeong Song , Soon-Wo Kwon , Hang-Yeon Weon; J. Microbiol. 2014;52(12):990-994. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4587-x

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Abstract: One strain, designated KIS31-44T, was isolated from a soil sample collected from Dokdo Island, South Korea. The strain is Gram-stain-positive, aerobic, non-spore-forming and nonmotile. It grows optimally at 28–30°C, at pH 7.0 and 0% NaCl. 16S rRNA gene sequence analysis showed that strain KIS31-44T belonged to the genus Nocardioides and shared the highest sequence similarities with Nocardioides aestuarii JC2056T (95.5%) and Nocardioides terrae VA15T (95.0%). The major fatty acids of strain KIS31-44T were C17:1 ω6c, C18:1 ω9c, summed feature 3 (C16:1 ω6c and/or C16:1 ω7c), iso-C16:0, C18:0 10-methyl (TBSA), C16:0 2-OH, C17:0 10-methyl, and iso-C16:1 H. The major isoprenoid quinone was MK-8 (H4). The strain contained diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major polar lipids. The peptidoglycan structure was A3γ-type with LL-diaminopimelic acid. Based on these data, the isolate represents one novel species in the genus Nocardioides, for which the name Nocardioides paucivorans sp. nov. (type strain KIS31-44T =DSM 27142T =KACC 17309T) is proposed.

Research Support, Non-U.S. Gov'ts

Effect of Long-Term Different Fertilization on Bacterial Community Structures and Diversity in Citrus Orchard Soil of Volcanic Ash: Jae Ho Joa , Hang Yeon Weon , Hae Nam Hyun , Young Chull Jeun , Sang Wook Koh; J. Microbiol. 2014;52(12):995-1001. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4129-6

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32 Citations

Abstract: This study was conducted to assess bacterial species richness, diversity and community distribution according to different fertilization regimes for 16 years in citrus orchard soil of volcanic ash. Soil samples were collected and analyzed from Compost (cattle manure, 2,000 kg/10a), 1/2 NPK+compost (14-20-14+2,000 kg/10a), NPK+compost (28-40-28+2,000 kg/10a), NPK (28-40-28 kg/10a), 3 NPK (84-120-84 kg/10a), and Control (no fertilization) plot which have been managed in the same manners with compost and different amount of chemical fertilization. The range of pyrosequencing reads and OTUs were 4,687–7,330 and 1,790–3,695, respectively. Species richness estimates such as Ace, Chao1, and Shannon index were higher in 1/2 NPK+compost than other treatments, which were 15,202, 9,112, 7.7, respectively. Dominant bacterial groups at level of phylum were Proteobacteria, Acidobacteria, and Actinobacteria. Those were occupied at 70.9% in 1/2 NPK+compost. Dominant bacterial groups at level of genus were Pseudolabrys, Bradyrhizobium, and Acidobacteria. Those were distributed at 14.4% of a total of bacteria in Compost. Soil pH displayed significantly closely related to bacterial species richness estimates such as Ace, Chao1 (p<0.05) and Shannon index (p<0.01). However, it showed the negative correlation with exchangeable aluminum contents (p<0.05). In conclusion, diversity of bacterial community in citrus orchard soil was affected by fertilization management, soil pH changes and characteristics of volcanic ash.

Effect of Zinc on Growth Performance, Gut Morphometry, and Cecal Microbial Community in Broilers Challenged with Salmonella enterica serovar Typhimurium: Yuxin Shao , Zhao Lei , Jianmin Yuan , Ying Yang , Yuming Guo , Bingkun Zhang; J. Microbiol. 2014;52(12):1002-1011. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4347-y

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76 Citations

Abstract: To evaluate the effects of supplemental zinc on growth performance, gut morphometry, and the cecal microbial community in broilers challenged with Salmonella typhimurium, 180, 1-day-old male Cobb 500 broiler chicks were randomly assigned to 3 treatments with ten replicates for a 42 day experiment. The 3 treatments were: unchallenged, S. typhimurium- challenged, and S. typhimurium-challenged with 120 mg/kg of zinc supplementation in the diet. Salmonella infection caused a reduction in body-weight gain and feed intake, disrupted the intestinal structure by decreasing the villus-height/crypt-depth ratio of the ileum and increasing the apoptotic index of ileal epithelial cells. Moreover, the cecal microbial community was altered by Salmonella infection, as demonstrated by a reduced number of Lactobacillus and total bacteria. Dietary zinc supplementation improved growth performance by increasing the body-weight gain and feed intake in the challenged broilers. In addition, zinc repaired intestinal injury by reducing the apoptotic index of ileal epithelial cells, enhancing villus height and the villusheight/ crypt-depth ratio of the ileum, and the proliferation index of ileal epithelial cells. Finally, zinc regulated the cecal microbial community by increasing the number of total bacteria and beneficial Lactobacillus bacteria, and reducing the number of Salmonella. The results indicated that dietary zinc supplementation improved growth performance, intestinal morphology, and intestinal microbiota in S. typhimurium- challenged broilers.

Transformation of Inorganic P Fractions of Soil and Plant Growth Promotion by Phosphate-solubilizing Ability of Penicillium oxalicum I1: Mingbo Gong , Peng Du , Xue Liu , Changxiong Zhu; J. Microbiol. 2014;52(12):1012-1019. Published online November 3, 2014; DOI: https://doi.org/10.1007/s12275-014-4406-4

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18 Citations

Abstract: The solubilization of tricalcium phosphate is often considered as the standard for screening of most phosphate-solubilizing microorganisms (PSMs). However, usually the effect of large-scale application of PSM on the promotion of crop growth varies. This study presents an efficient method for screening and testing phosphate-solubilizing fungus that enhance plant growth. A fungus Penicillium oxalicum I1 (PI1) was isolated and identified that had high ability of phosphate- solubilization and could utilize maize root exudates as sources, and propagate well in vitro and in soil. P-I1 excreted oxalic acid and reached 593.9 μg/ml, and the pH value was decreased from 6.90 to 1.65 in 26 h. The amount of P-I1 increased by 48-fold in 28 d and was maintained for 49 d in soil. PSM showed selectivity on the transformation of the different forms of phosphorus, a wide range of insoluble phosphates, such as Ca8H2(PO4)6·5H2O, AlPO4, FePO4, and Ca10(PO4)6(OH)2, were converted to soluble CaHPO4 in soil, and CaHPO4 was also inhibited from being converted into insoluble phosphate by P-I1. The Ca2-P content reached 27.11 μg/g soil on day 28 at 20°C, which increased by 110.32%, and plant growth promotion was tested and verified, the
results
showed that maize yield increased remarkably than control after inoculated P-I1, maize yield increased maximum by 14.47%. The data presented that P-I1 appear attractive for exploring their plant growth-promoting activity and potential field application.

The Role of Wheat Germ Agglutinin in the Attachment of Pseudomonas sp. WS32 to Wheat Root: Jian Zhang , Liyuan Meng , Yuanyuan Cao , Huiping Chang , Zhongyou Ma , Leni Sun , Ming Zhang , Xinyun Tang; J. Microbiol. 2014;52(12):1020-1024. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4089-x

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Abstract: Wheat germ agglutinin (WGA), which is secreted on the surface of wheat root, has been defined as a protein that reversibly and non-enzymatically binds to specific carbohydrates. However, little attention has been paid to the function of WGA in the attachment of bacteria to their host plants. The aim of this study was to investigate the role of WGA in the attachment of Pseudomonas sp. WS32 to wheat roots. Wheat roots were initially treated with double-distilled water, WGA-H (WGA solution that was heated at 100°C for 15 min) and WGA, independently. Subsequently, the roots were coincubated with cell solutions (109 cells/ml). A dilution plate
method
using a solid nutrient medium was employed to determine the adsorption of WS32 to wheat roots. WGA was labeled with fluorescein isothiocyanate and detected using the fluorescent in situ hybridization (FISH) technique. The number of adsorptive WS32 cells on wheat roots was significantly increased when the wheat roots were pretreated with WGA, compared with the control treatment (p = 0.01). However, WGA-H failed to increase the amount of bacterial cells that attached to the wheat roots because of the loss of its physiological activity. The FISH assay also revealed that more cells adhered to WGA-treated wheat roots than to control or WGA-H-treated roots. The results indicated that WGA can mediate Pseudomonas strain WS32’s adherence to wheat seedling roots. The findings of this study provide a better understanding of the processes involved in plant-microbe interactions.

Mycoflora Dynamics Analysis of Korean Traditional Wheat-based Nuruk: Jyotiranjan Bal , Suk-Hyun Yun , Ha-Yeon Song , Soo-Hwan Yeo , Jae Hyun Kim , Jung-Mi Kim , Dae-Hyuk Kim; J. Microbiol. 2014;52(12):1025-1029. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4620-0

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30 Citations

Abstract: The growing popularity of traditional Korean alcoholic beverages has led to a demand for quality enhancement of the traditional starter culture nuruk, which consists primarily of wheat. Therefore, this study focused on mycoflora characterization and the temporal variations in traditional wheatbased nuruks fermented at two representative traditional temperature conditions for 30 days. Nuruk A was fermented at a constant temperature of 36°C for 30 days and nuruk B was fermented at a high initial temperature of 45°C for 10 days followed by 35°C for 20 days. The average mycoflora load in the two different nuruk conditions did not vary significantly between the 0 and 30 day cultures, and a maximum load of 8.39 log CFU/g was observed for nuruk A on culture day 3 and 7.87 log CFU/g for nuruk B on culture day 30. Within two samples, pH was negatively correlated with temporal changes in mycoflora load. The pH of nuruk A was significantly lower than that of nuruk B at all of the time points evaluated. Culture- dependent characterization led to the identification of 55 fungal isolates belonging to 9 genera and 15 species, with the most prominent genera comprising Lichtheimia, Penicillium, Trametes, Aspergillus, Rhizomucor, and Mucor. A total of 25 yeast isolates were characterized belonging to 6 genera and 7 species, the most prominent among which were Rhodotorula, Pichia, Debaryomyces, Saccharomycopsis, and Torulospora. Mycofloral community dynamics analysis revealed that both samples A and B varied considerably with respect to the fungal communities over a span of 30 days.

Proteomic and Functional Analyses of a Novel Porin-like Protein in Xanthomonas oryzae pv. oryzae: Hye-Jee Park , Sang-Won Lee , Sang-Wook Han; J. Microbiol. 2014;52(12):1030-1035. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4442-0

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13 Citations

Abstract: Proteomic analysis is a useful technique for postulating and elucidating protein functions. In the present work, a shotgun proteomic analysis was used to identify functions of the PXO_03968 gene (previously known as the ax21) from Xanthomonas oryzae pv. oryzae (Xoo), a causal agent for bacterial blight disease in rice. Structural prediction performed on the protein sequence encoded by PXO_03968 reveals that it encodes a putative porin-like protein, possessing a β-barrel domain with 10 β-strands and a signal peptide at the Nterminus. We renamed the gene as an omp1X (outer membrane protein 1 in Xoo), generated its knock out mutant (XooΔomp1X), and compared the protein expression level in the mutant to that in the wild type. A total of 106 proteins displayed more than 1.5-fold difference in expression between the mutant and the wild type strains. COG analysis revealed that these proteins are involved in cell motility as well as signal transduction. In addition, phenotypic analysis demonstrated that motility and biofilm formation in XooΔomp1X are lower than the wild type. These results provide new insights into the functions of outer membrane proteins in Gram-negative bacteria.

VvpM, an Extracellular Metalloprotease of Vibrio vulnificus, Induces Apoptotic Death of Human Cells: Mi-Ae Lee , Jeong-A Kim , Yu Jin Yang , Mee-Young Shin , Soon-Jung Park , Kyu-Ho Lee; J. Microbiol. 2014;52(12):1036-1043. Published online November 3, 2014; DOI: https://doi.org/10.1007/s12275-014-4531-0

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20 Citations

Abstract: A pathogenic bacterium, Vibrio vulnificus produces various extracellular proteases including the elastolytic metalloprotease, VvpE. In silico analysis of its genome revealed a VvpEhomologous protease, VvpM whose proteolytic activity was abolished by specific inhibitors against metalloproteases. To investigate whether this newly identified protease has pathogenic role in host interaction in addition to proteolytic role, human cell lines were incubated with recombinant VvpM (rVvpM). rVvpM-challenged cells showed typical morphological changes found in cells under apoptosis. Apoptotic cell death was further evidenced by estimating the Annexin V-stained cells, whose proportions were dependent upon the concentrations of rVvpM treated to human cells. To elucidate the signaling pathway for VvpM-induced apoptosis, three MAPKs were tested if their activation were mediated by rVvpM. ERK1/2 was phosphorylated by treatment of rVvpM and rVvpM-induced cell death was blocked by a specific inhibitor against ERK1/2. In rVvpM-treated cells, the cytosolic levels of cytochrome c were increased in a VvpM concentration- dependent manner, while the levels of cytochrome c in mitochondria were decreased. Cell deaths were accompanied by apparent cleavages of procaspases-9 and -3 to the active caspases-9 and -3, respectively. Therefore, this study demonstrates that an extracellular metalloprotease of V. vulnificus, VvpM induces apoptosis of human cells via a pathway consisting of ERK activation, cytochrome c release, and then activation of caspases-9 and -3.

Pseudomonas aeruginosa-induced IL-1β Production is Inhibited by Sophora flavescens via the NF-κB/inflammasome Pathways: Jung-Hoon Lee , Heesung Shin , Yong-Jae Kim , Se-Hwan Paek , Shouguang Jin , Un-Hwan Ha; J. Microbiol. 2014;52(12):1044-1049. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4512-3

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16 Citations

Abstract: The proinflammatory cytokine interleukin-1β plays an important role in protecting the host against airway infection; however, it can also trigger a massive influx of neutrophils into the airways, causing tissue damage. Anti-inflammatory treatments are particularly in demand for patients suffering from chronic inflammatory diseases. Sophora flavescens is a traditional herbal medicine used to reduce inflammation, but no study has examined its ability to block IL-1β production. Here, we show that S. flavescens reduced the Pseudomonas aeruginosa-induced expression of IL-1β by lung epithelial cells and macrophages. S. flavescens was also effective at reducing IL-1β production induced by either Staphylococcus aureus or phorbol 12-myristate 13-acetate, indicating that the effect is generalizable to diverse inflammatory stimuli. In addition, S. flavescens blocked the phosphorylation of IKKα/β, key upstream kinases involved in the degradation of IκBα, and the cleavage of caspase-1, a key component of the inflammasome. Thus, this study demonstrates that S. flavescens exerts its anti-inflammatory effects by blocking P. aeruginosa-mediated NF-κB/inflammasome activation and the subsequent production of IL-1β.

Note] Oceanobacillus gochujangensis sp. nov., Isolated from gochujang a Traditional Korean Fermented Food: Seo-Jung Jang , Yu-Jin Kim , Sul-Hee Lee , Young-Seo Park , Jung-Min Park , Dong-Hoon Bai; J. Microbiol. 2014;52(12):1050-1055. Published online July 30, 2014; DOI: https://doi.org/10.1007/s12275-014-4220-z

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Abstract: A Gram-stain-positive, polar flagella-containing, rod-shaped, obligate aerobic, endospore-forming bacterium, strain TK1655T, was isolated from the traditional Korean food gochujang. The 16S rRNA sequence of strain TK1655T was a member of the genus Oceanobacillus similar to that of the type strain of Oceanobacillus oncorhynchi subsp. incaldanensis DSM 16557T (97.2%), O. oncorhynchi subsp. oncorhynchi JCM 12661T (97.1%), O. locisalsi KCTC 13253T (97.0%), and O. sojae JCM 15792T (96.9%). Strain TK1655T was oxidase and catalase positive. Colonies were circular, smooth, low convex, cream in colour, and measured about 0.5–1.0 mm in diameter. The range for growth was 20–40°C (optimal, 30°C), pH 6.0– 10.0 (optimal, 7.0), and 2–16% (w/v) NaCl (optimal, 2%). Additionally, the cells contained meso-DAP, and the predominant isoprenoid quinone was MK-7. The complex polar lipids were consisted of diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylcholine (PC). The major cellular fatty acid components were iso-C15:0, anteiso-C15:0, iso-C16:0, and anteiso-C17:0, and the DNA G+C content was 40.5%. DNA-DNA relatedness of our novel strain and reference strain O. locisalsi KCTC 13253T, O. oncorhynchi subsp. incaldanensis DSM 16557T, O. oncorhynchi subsp. oncorhynchi JCM 12661T was 45.7, 43.8, and 41.9%. From the
results
of phenotypic, chemotaxonomic, and phylogenetic analyses of strain TK1655T, we propose the novel species Oceanobacillus gochujangensis sp. nov. The type strain is TK1655T (=KCCM 101304T =KCTC 33014T =CIP 110582T =NBRC 109637T).

Erratum] Deodorization of Pig Slurry and Characterization of Bacterial Diversity Using 16S rDNA Sequence Analysis: Ok-Hwa Hwang , Sebastian Raveendar , Young-Ju Kim , Ji-Hun Kim , Tae-Hun Kim , Dong-Yoon Choi , Che Ok Jeon , Sung-Back Cho , Kyung-Tai Lee; J. Microbiol. 2014;52(12):1056-1056.; DOI: https://doi.org/10.1007/s12275-014-0704-0

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Abstract: In the article by Hwang et al. published in Journal of Microbiology 2014; 52, 918-919. Jung-Woo Choi was omitted as the 5th author of this paper. The authors should be Ok-Hwa Hwang1†, Sebastian Raveendar1†, Young-Ju Kim1, Ji-Hun Kim1, Jung-Woo Choi1, Tae-Hun Kim1, Dong-Yoon Choi1, Che Ok Jeon2*, Sung-Back Cho1*, and Kyung-Tai Lee1*

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