Journal of Microbiology

Volume 54(6); June 2016

Review

MINIREVIEW] Advances in novel influenza vaccines: a patent review: Jae-Min Song; J. Microbiol. 2016;54(6):403-412. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6176-7

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Abstract: The threat of a major human influenza pandemic such as the avian H5N1 or the 2009 new H1N1 has emphasized the need for effective prevention strategies to combat these pathogens. Although egg based influenza vaccines have been well established for a long time, it remains an ongoing public health need to develop alternative production methods that ensures improved safety, efficacy, and ease of administration compared with conventional influenza vaccines. This article is intended to cover some of the recent advances and related patents on the development of influenza vaccines including live attenuated, cell based, genomic and synthetic peptide vaccines.

Journal Articles

Calculibacillus koreensis gen. nov., sp. nov., an anaerobic Fe(III)-reducing bacterium isolated from sediment of mine tailings: Ui-Gi Min , So-Jeong Kim , Heeji Hong , Song-Gun Kim , Joo-Han Gwak , Man-Young Jung , Jong-Geol Kim , Jeong-Geol Na , Sung-Keun Rhee; J. Microbiol. 2016;54(6):413-419. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6086-8

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Abstract: A strictly anaerobic bacterium, strain B5T, was isolated from sediment of an abandoned coal mine in Taebaek, Republic of Korea. Cells of strain B5T were non-spore-forming, straight, Gram-positive rods. The optimum pH and temperature for growth were pH 7.0 and 30°C, respectively, while the strain was able to grow within pH and temperature ranges of 5.5– 7.5 and 25–45°C, respectively. Growth of strain B5T was observed at NaCl concentrations of 0 to 6.0% (w/v) with an optimum at 3.0–4.0% (w/v). The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, an unknown phospholipid and three unknown polar lipids. Strain B5T grew anaerobically by reducing nitrate, nitrite, ferric-citrate, ferric-nitrilotriacetate, elemental sulfur, thiosulfate, and anthraquinone- 2-sulfonate in the presence of proteinaceous compounds, organic acids, and carbohydrates as electron donors. The isolate was not able to grow by fermentation. Strain B5T did not grow under aerobic or microaerobic conditions. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain B5T is most closely related to the genus Tepidibacillus (T. fermentans STGHT; 96.3%) and Vulcanibacillus (V. modesticaldus BRT; 94.6%). The genomic DNA G+C content (36.9 mol%) of strain B5T was higher than those of T. fermentans STGHT (34.8 mol%) and V. modesticaldus BRT (34.5 mol%). Based on its phenotypic, chemotaxonomic, and phylogenetic properties, we describe a new species of a novel genus Calculibacillus, represented by strain B5T (=KCTC 15397T =JCM 19989T), for which we propose the name Calculibacillus koreensis gen. nov., sp. nov.

Dankookia rubra gen. nov., sp. nov., an alphaproteobacterium isolated from sediment of a shallow stream: Wan-Hoe Kim , Do-hak Kim , Keunsoo Kang , Tae-Young Ahn; J. Microbiol. 2016;54(6):420-425. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6054-3

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Abstract: WS-10T–a Gram-negative, non-motile, and aerobic bacterial strain–was isolated from the sediment of a shallow stream in Korea. The optimum ranges of temperature and pH for growth were 20–40°C (optimum 28°C) and pH 6.0–8.0 (optimum pH 7.0), respectively. The DNA G+C content of strain WS-10T was 72.7 mol%. The major fatty acids (>5%) were summed feature 8 (C18:1 ω7c), summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:0, and C18:1 2-OH. The major polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, and unidentified aminolipids. Q-10 was the predominant respiratory quinone. The highest similarities in the 16S rRNA gene sequence were shown with Paracraurococcus ruber (95.3%), Belnapia soli (95.3%), B. moabensis (95.1%), and B. rosea (95.0%). A phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that strain WS-10T formed a distinct line within a clade containing the genera Paracraurococcus, Craurococcus, and Belnapia in the family Acetobacteraceae. On the basis of polyphasic evidence, strain WS-10T represents a novel species of a new genus in the family Acetobacteraceae, for which the name Dankookia rubra gen. nov., sp. nov. is proposed. The type strain of the type species is WS-10T (= KACC 18533T = JCM 30602T).

PprM is necessary for up-regulation of katE1, encoding the major catalase of Deinococcus radiodurans, under unstressed culture conditions: Sun-Wook Jeong , Ho Seong Seo , Min-Kyu Kim , Jong-Il Choi , Heon-Man Lim , Sangyong Lim; J. Microbiol. 2016;54(6):426-431. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6175-8

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Abstract: Deinococcus radiodurans is a poly-extremophilic organism, capable of tolerating a wide variety of different stresses, such as gamma/ultraviolet radiation, desiccation, and oxidative stress. PprM, a cold shock protein homolog, is involved in the radiation resistance of D. radiodurans, but its role in the oxidative stress response has not been investigated. In this study, we investigated the effect of pprM mutation on catalase gene expression. pprM disruption decreased the mRNA and protein levels of KatE1, which is the major catalase in D. radiodurans, under normal culture conditions. A pprM mutant strain (pprMMT) exhibited decreased catalase activity, and its resistance to hydrogen peroxide (H2O2) decreased accordingly compared with that of the wild-type strain. We confirmed that RecG helicase negatively regulates katE1 under normal culture conditions. Among katE1 transcriptional regulators, the positive regulator drRRA was not altered in pprM-, while the negative regulators perR, dtxR, and recG were activated more than 2.5-fold in pprMMT. These findings suggest that PprM is necessary for KatE1 production under normal culture conditions by down-regulation of katE1 negative regulators.

Identification of D-amino acid dehydrogenase as an upstream regulator of the autoinduction of a putative acyltransferase in Corynebacterium glutamicum: Jung-Hoon Lee , Yong-Jae Kim , Hee-Sung Shin , Heung-Shick Lee , Shouguang Jin , Un-Hwan Ha; J. Microbiol. 2016;54(6):432-439. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6046-3

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Abstract: Expression of a putative acyltransferase encoded by NCgl- 0350 of Corynebacterium glutamicum is induced by cell-free culture fluids obtained from stationary-phase growth of both C. glutamicum and Pseudomonas aeruginosa, providing evidence for interspecies communication. Here, we further confirmed that such communication occurs by showing that acyltransferase expression is induced by culture fluid obtained from diverse Gram-negative and -positive bacterial strains, including Escherichia coli, Salmonella Typhimurium, Bacillus subtilis, Staphylococcus aureus, Mycobacterium sp. strain JC1, and Mycobacterium smegmatis. A homologous acyltransferase encoded by PA5238 of P. aeruginosa was also induced by fluids obtained from P. aeruginosa as well as other bacterial strains, as observed for NCgl0350 of C. glutamicum. Because C. glutamicum is difficult to study using molecular approaches, the homologous gene PA5238 of P. aeruginosa was used to identify PA5309 as an upstream regulator of expression. A homologous D-amino acid dehydrogenase encoded by NCgl- 2909 of C. glutamicum was cloned based on amino acid similarity to PA5309, and its role in the regulation of NCgl0350 expression was confirmed. Moreover, NCgl2909 played positive roles in growth of C. glutamicum. Thus, we identified a D-amino acid dehydrogenase as an upstream regulator of the autoinduction of a putative acyltransferase in C. glutamicum.

Purification, crystallization, and preliminary X-ray crystallographic analysis of the Group III chaperonin from Carboxydothermus hydrogenoformans: Young Jun An , Sara E. Rowland , Frank T. Robb , Sun-Shin Cha; J. Microbiol. 2016;54(6):440-444. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6089-5

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Abstract: Chaperonins (CPNs) are megadalton sized ATP-dependent nanomachines that facilitate protein folding through complex cycles of complex allosteric articulation. They consist of two back-to-back stacked multisubunit rings. CPNs are usually classified into Group I and Group II. Here, we report the crystallization of both the AMPPNP (an ATP analogue) and ADP bound forms of a novel CPN, classified as belonging to a third Group, recently discovered in the extreme thermophile Carboxydothermus hydrogenoformans. Crystals of the two forms were grown by the vapor batch crystallization
method
at 295 K. Crystals of the Ch-CPN/AMPPNP complex diffracted to 3.0 Å resolution and belonged to the space group P422, with unit-cell parameters a = b = 186.166, c = 160.742 Å. Assuming the presence of four molecules in the asymmetric unit, the solvent content was estimated to be about 60.02%. Crystals of the Ch-CPN/ADP complex diffracted to 4.0 Å resolution and belonged to the space group P4212, with unit-cell parameters a = b = 209.780, c = 169.813Å. Assuming the presence of four molecules in the asymmetric unit, the solvent content was estimated to be about 70.19%.

Characteristics of the community-genotype sequence type 72 methicillin-resistant Staphylococcus aureus isolates that underlie their persistence in hospitals: Eun-Jeong Joo , Ji-Young Choi , Doo Ryeon Chung , Jae-Hoon Song , Kwan Soo Ko; J. Microbiol. 2016;54(6):445-450. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6157-x

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Abstract: Panton-Valentine leukocidin-negative methicillin-resistant Staphylococcus aureus (MRSA) clone ST72, known as a major community-associated MRSA in Korea, has emerged as an important pathogen in hospitals. To understand bacterial properties that underlie transformation of this clone into a nosocomial pathogen, we compared characteristics of the community-genotype ST72 MRSA isolates with those of ST5 and ST239 MRSA, which have been predominant nosocomial MRSA clones in Korea. Several genes associated with adhesion and virulence were absent or rarely found in ST72 isolates. Many ST72 isolates (70.1%) belonged to agr group I, but the agr group of other ST72 isolates could not be determined. As indicated by δ-hemolysin production, ST72 isolates expressed fully functional agr, whereas agr dysfunction was observed in ST5 and ST239 isolates. In the biofilm formation assay, no upregulation of biofilm-forming activity of ST72 MRSA was detected. However, ST72 isolates demonstrated persistence under hypotonic and desiccating conditions (survival rates 72.3% and 33.9%, respectively), which was similar to characteristics of ST5 or ST239 isolates. ST72- MRSA isolates showed low virulence, but properties of their functional agr system could facilitate their spread in hospitals. In conclusion, tolerance to stressful environments, e.g., hypotonic and dry conditions, may also contribute to survival of the community-associated MRSA clones in healthcare facilities.

Roles of human apolipoprotein E in the infectivity and replication of hepatitis C virus genotype 2a: Bo-Kyoung Jung , Hye-Ran Kim , Gyu-Nam Park , Guangxiang Luo , Kyung-Soo Chang; J. Microbiol. 2016;54(6):451-458. Published online May 27, 2016; DOI: https://doi.org/10.1007/s12275-016-6099-3

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Abstract: Hepatitis C virus (HCV) infection is associated with lipoproteins, and apolipoprotein E (apoE) plays an essential role in infectious HCV particles. Although the role of apoE in HCV infection is well known, its role in the replication of HCV remains unclear. The aims of this study were to determine the role of apoE in the RNA replication of major HCV genotypes 1b and 2a, and to determine whether this role is HCVgenotype- dependent using HCV genotype 1b replicon cells and HCV genotype 2a producing (HP) cells. HCV infection was blocked in Huh7.5 cells treated with low-density lipoproteins, very low-density lipoproteins, or apoE3. An apoE3- specific monoclonal antibody also efficiently neutralized HCV infectivity, and HCV infection was dramatically suppressed by the knockdown of apoE expression with an apoE-specific small interfering RNA, suggesting a requirement for apoE in infectious HCV particles. HCV RNA replication was not affected in HP cells treated with each apoE isoform or transfected with apoE-specific siRNAs. However, the knockdown of apoE expression suppressed RNA replication of HCV genotype 1b. The siRNA-mediated knockdown of apoE, apoA1, and apoB expression also suppressed the RNA replication of HCV genotype 1b, but not that of HCV genotype 2a. Taken together, these findings indicate that apoE plays an important role in HCV genotype 2a infection and in HCV genotype 1b RNA replication, but not in the replication of HCV genotype 2a. These results provide important information for the future development of HCV-genotypespecific anti-HCV agents.

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