Journal of Microbiology

Volume 51(5); October 2013

Review

MINIREVIEW] Bioactive Activities of Natural Products against Herpesvirus Infection: Myoungki Son , Minjung Lee , Gi-Ho Sung , Taeho Lee , Yu Su Shin , Hyosun Cho , Paul M. Lieberman , Hyojeung Kang; J. Microbiol. 2013;51(5):545-551. Published online October 31, 2013; DOI: https://doi.org/10.1007/s12275-013-3450-9

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34 Citations

Abstract: More than 90% of adults have been infected with at least one human herpesvirus, which establish long-term latent infection for the life of the host. While anti-viral drugs exist that limit herpesvirus replication, many of these are ineffective against latent infection. Moreover, drug-resistant strains of herpesvirus emerge following chemotherapeutic treatment. For example, resistance to acyclovir and related nucleoside analogues can occur when mutations arise in either HSV thymidine kinase or DNA polymerases. Thus, there exists an unmet medical need to develop new anti-herpesvirus agents with different mechanisms of action. In this Review, we discuss the promise of anti-herpetic substances derived from natural products including extracts and pure compounds from potential herbal medicines. One example is Glycyrrhizic acid isolated from licorice that shows promising antiviral activity towards human gammaherpesviruses. Secondly, we discuss anti-herpetic mechanisms utilized by several natural products in molecular level. While nucleoside analogues inhibit replicating herpesviruses in lytic replication, some natural products can disrupt the herpesvirus latent infection in the host cell. In addition, natural products can stimulate immune responses against herpesviral infection. These findings suggest that natural products could be one of the best choices for development of new treatments for latent herpesvirus infection, and may provide synergistic anti-viral activity when supplemented with nucleoside analogues. Therefore, it is important to identify which natural products are more efficacious anti-herpetic agents, and to understand the molecular mechanism in detail for further advance in the anti-viral therapies.

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

Morphological and Genetic Characteristics of Newly Crossbred Cauliflower Mushroom (Sparassis latifolia): Hong-Duck Sou , Rhim Ryoo , Sung-Ryul Ryu , Kang-Hyeon Ka , Hyun Park , Sung-Hyun Joo; J. Microbiol. 2013;51(5):552-557. Published online June 25, 2013; DOI: https://doi.org/10.1007/s12275-013-2666-z

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Abstract: Cauliflower mushroom (Sparassis latifolia or S. crispa) is popular for food and medicine. Importance of new varieties of Sparassis was raised and studied widely by protection system of UPOV. In this study, 10 crossbred strains of Sparassis latifolia that specifically expressed distinctive features during basidiocarp formation and mycelium growth were applied to sawdust medium inoculated with S. latifolia mycelia. The 10 crossbred strains were divided into 3 groups on the basis of morphological (size of marginal wave and basidiocarp color) and genetic characteristics. Each phenotype of the parent and crossbred strains represented 3 marginal wave-sizes (large, medium, and small) and 3 color notations (NN155D, 163C, and 8D). Our result suggests that morphological characteristics of cauliflower mushroom can be affected by various environmental and genetic stimuli under artificial conditions such as crossbreed. Also this research showed genetic differences among breeding isolates and their morphological characteristics were correlated with the molecular data within parent and crossed strain.

Bacterial Diversity and Composition of an Alkaline Uranium Mine Tailings-Water Interface: Nurul H. Khan , Viorica F. Bondici , Prabhakara G. Medihala , John R. Lawrence , Gideon M. Wolfaardt , Jeff Warner , Darren R. Korber; J. Microbiol. 2013;51(5):558-569. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-3075-z

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14 Citations

Abstract: The microbial diversity and biogeochemical potential associated with a northern Saskatchewan uranium mine watertailings interface was examined using culture-dependent and -independent techniques. Morphologically-distinct colonies from uranium mine water-tailings and a reference lake (MC) obtained using selective and non-selective media were selected for 16S rRNA gene sequencing and identification, revealing that culturable organisms from the uranium tailings interface were dominated by Firmicutes and Betaproteobacteria; whereas, MC organisms mainly consisted of Bacteroidetes and Gammaproteobacteria. Ion Torrent (IT) 16S rRNA metagenomic analysis carried out on extracted DNA from tailings and MC interfaces demonstrated the dominance of Firmicutes in both of the systems. Overall, the tailings-water interface environment harbored a distinct bacterial community relative to the MC, reflective of the ambient conditions (i.e., total dissolved solids, pH, salinity, conductivity, heavy metals) dominating the uranium tailings system. Significant correlations among the physicochemical data and the major bacterial groups present in the tailings and MC were also observed. Presence of sulfate reducing bacteria demonstrated by culture-dependent analyses and the dominance of Desulfosporosinus spp. indicated by Ion Torrent analyses within the tailings-water interface suggests the existence of anaerobic microenvironments along with the potential for reductive metabolic processes.

Analysis of Bacterial Diversity in Sponges Collected off Chujado, an Island in Korea, Using Barcoded 454 Pyrosequencing: Analysis of a Distinctive Sponge Group Containing Chloroflexi: In-Hye Jeong , Kyoung-Ho Kim , Jin-Sook Park; J. Microbiol. 2013;51(5):570-577. Published online October 31, 2013; DOI: https://doi.org/10.1007/s12275-013-3426-9

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14 Citations

Abstract: The bacterial diversity of 14 sponges belonging to 5 different orders that were collected around Chuja Island, Korea was investigated using barcoded 454 pyrosequencing. The sponges contained many unidentified bacterial groups (e.g. more than half of the taxa at the family level) that were known only in environmental sequences and obtained from culture-independent methods. Five of the sponges were clustered into one notable group (CF group), which was distinguished from the other sponges in accordance with bacterial composition (the other sponges may be separated into more groups but clustering is not clear). The CF group contained high amounts of Chloroflexi (25.0–47.7%) and moderate amounts of Gemmatimonadetes (2.3–7.0%), AncK6 (0.6–2.2%), PAUC34f (0.8–6.0%), Acidobacteria (3.7–9.6%), and SBR1093 (1.8–5.6%) exclusively or almost exclusively to this group. Sponges in the CF group also showed higher diversity (e.g. Shannon index) than the other sponges and contained group-specific taxonomic lineages (e.g. class or family level) from group-specific phyla and even from the Proteobacteria and Actinobacteria, which were detected in all sponges at the phylum level. The CF group may be one of the most distinctive groups in sponges in terms of bacterial diversity.

Research Support, U.S. Gov't, Non-P.H.S.

Combined Effect of Microbial and Chemical Control Agents on Subterranean Termites: Maureen S. Wright , Alan R. Lax; J. Microbiol. 2013;51(5):578-583. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-2628-5

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8 Citations

Abstract: Termite mortality was measured when fungi were combined with bacteria or a chemical termiticide to determine whether a synergistic effect occurred. The fungus Beauveria bassiana was combined with the non-repellant chemical termiticide imidacloprid. Of the three B. bassiana strains tested one, B. bassiana ATCC 90519, was sufficiently pathogenic on its own that the advantage of a supplementary chemical treatment was marginal. The mortality caused by another fungal strain, B. bassiana ATCC 26037, was improved in combination with imidacloprid at both of the tested chemical concentrations over the first 14 days. The remaining fungal strain, B. bassiana ATCC 90518, demonstrated an overall mortality rate in combination with imidacloprid of 82.5%, versus a rate of 65.0% for the fungus alone. The fungus Isaria fumosorosea (Ifr) was combined with the bacterium Bacillus thuringiensis (Bt). On day 5, Ifr, Bt, and the combined treatment at a 106 spores or cells/ml dosage caused 8.8%, 22.5%, and 15.0% mortality, respectively. The Bt and combined mortality rates are not significantly different. Control mortality on day 5 was 5.0%. On day 13 the combined 106 treatment mortality rate was 91.3%, which was significantly higher than all other treatments: control at 17.5%, Ifr at 36.3% and Bt at 35.0%. When Ifr and Bt were applied at a 109 spores or cells/ml dosage, Ifr alone caused a mortality rate of 97.5% as early as day 5. The combination with Bt could not significantly increase the effectiveness of this dosage. These data demonstrate the potential for synergistic effects of fungal and chemical treatment methods, thereby broadening the use of microbial control agents and reducing the quantity of chemical agents necessary to effect control.

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

Live/Dead State Is Not the Factor Influencing Adhesion Ability of Bifidobacterium animalis KLDS2.0603: Li-Qun Wang , Feng Zhao , Fei Liu , Xiang-Chen Meng; J. Microbiol. 2013;51(5):584-589. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-2632-9

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14 Citations

Abstract: Two essential requirements for probiotic bifidobacteria are that they be “live” and have “colonization” ability, following FAO/WHO guideline recommendations. The amount of research on the adhesion ability of bifidobacteria compares poorly with that of other probiotic bacteria, such as lactobacilli. The aim of the present study was to determine how gastrointestinal conditions affect the adhesion ability of bifidobacteria, and to investigate the relationship between the adhesion ability and the live/dead state of bifidobacteria. The adhesion ability of Bifidobacterium animalis KLDS2.0603 that had been subjected to the digestive enzymes, pepsin, trypsin, and proteinase K, was decreased significantly, but these treatments did not significantly change the strain’s survival rates, which were 98.78%, 97.60%, and 97.63% respectively. B. animalis KLDS2.0603 subjected to LiCl retained its adhesion ability but had a lower survival rate (59.28%) than the control group (P<0.01). B. animalis KLDS 2.0603 subjected to sodium metaperiodate exhibited higher adhesion ability than the control group (P<0.01), but the bacterial cells were killed totally. The results of transmission electron microscopy and laser scanning confocal microscopy showed that live/dead state of bifidobacteria was not one of the main factors that affected the adhesion ability of bifidobacteira, and that the substances affecting the adhesion ability of bifidobacteria were on the outer surface layer of the bifidobacterial cells. Our results also indicated that the substances related to the adhesion ability of bifidobacteria are proteinaceous. The above results will help us to understand the adhesion and colonization processes of bifidobacteria in the human gastrointestinal tract.

Alternative Mechanism for the Evaluation of Indole-3-Acetic Acid (IAA) Production by Azospirillum brasilense Strains and Its Effects on the Germination and Growth of Maize Seedlings: Oscar Masciarelli , Lucia Urbani , Herminda Reinoso , Virginia Luna; J. Microbiol. 2013;51(5):590-597. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-3136-3

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37 Citations

Abstract: We evaluated the production of indole-3-acetic acid (IAA) by Azospirillum brasilense strains in vitro (cell culture supernatants) and in vivo (stems and roots of maize seedlings) to clarify the role of this phytohormone as a signaling and effector molecule in the symbiotic interaction between maize and A. brasilense. The three strains all showed IAA production when cultured in NFb medium supplemented with 100 μg/ml L-tryptophan. The level of IAA production was 41.5 μg/ml for Yu62, 12.9 μg/ml for Az39, and 0.15 μg/ml for ipdC-. The release of IAA into culture medium by the bacteria appeared to be the main activator of the early growth promotion observed in the inoculated maize seedlings. The application of supernatants with different IAA contents caused significant differences in the seedling growth. This observation provides the basis for novel technological tools for effective quality control procedures on inoculants. The approach described can be incorporated into different inoculation methods, including line sowing, downspout, and foliar techniques, and increase the sustainability of symbiotic plant-bacteria systems.

Journal Article

Cyclooxygenase Inhibitors Reduce Biofilm Formation and Yeast-Hypha Conversion of Fluconazole Resistant Candida albicans: E. Abdelmegeed , Mona Ibrahim Shaaban; J. Microbiol. 2013;51(5):598-604. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-3052-6

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30 Citations

Abstract: The incidence of fluconazole-resistant Candida albicans has been increasing worldwide. Both biofilm and fungal morphogenesis are main virulence factors of C. albicans cells. Extracellular fungal prostaglandins are synthesized during biofilm adhesion and development and through yeast-hypha conversion. Hence, we targeted prostaglandin synthesis with various cyclooxygenase (COX) inhibitors (aspirin, diclofenac, ketoprofen, tenoxicam, and ketorolac) and assessed their effect on fungal adhesion, biofilm formation, and yeast-hypha conversion in clinical isolates of Fluconazole resistant C. albicans. Significant reduction in fungal adhesion and detachment of mature biofilm was attained down to 1 mM concentrations of anti-inflammatory agents. Microscopical examination of fungal cells in the presence of the tested drugs showed significant reduction of germ tube formation. Therefore, COX inhibitors have a significant effect on reduction of Candida adhesion and biofilm development in correlation with fungal morphogenesis. Moreover, inhibition of C. albicans by COX inhibitors gave synergistic activity with fluconazole suggesting that combination therapeutic strategies may be fruitful for management of infection of Fluconazole resistant C. albicans.

Research Support, Non-U.S. Gov't

Solid State Production of Polygalacturonase and Xylanase by Trichoderma Species Using Cantaloupe and Watermelon Rinds: Saleh A. Mohamed , Abdulrahman L. Al-Malki , Jalaluddin A. Khan , Saleh A. Kabli , Saleh M. Al-Garni; J. Microbiol. 2013;51(5):605-611. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-3016-x

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43 Citations

Abstract: Different solid state fermentation (SSF) sources were tested such as cantaloupe and watermelon rinds, orange and banana peels, for the production of polygalacturonase (PG) and xylanase (Xyl) by Trichoderma harzianum and Trichoderma virens. The maximum production of both PG and Xyl were obtained by T. harzianum and T. virnes grown on cantaloupe and watermelon rinds, respectively. Time course, moisture content, temperature, pH, supplementation with carbon and nitrogen sources were optimized to achieve the maximum production of both PG and Xyl of T. harzianum and T. virens using cantaloupe and watermelon rinds, respectively. The maximum production of PG and Xyl of T. harzianum and T. virens was recorded at 4–5 days of incubation, 50–66% moisture, temperature 28–35°C and pH 6–7. The influence of supplementary carbon and nitrogen sources was studied. For T. harzianum, lactose enhanced PG activity from 87 to 120 units/g solid, where starch and maltose enhanced Xyl activity from 40 to 55–60 units/g solid for T. virnes. Among the nitrogen sources, ammonium sulphate, ammonium nitrate, yeast extract and urea increased PG activity from 90 to 110–113 units/g solid for T. harzianum. Similarly, ammonium chloride, ammonium sulphate and yeast extract increased Xyl activity from 45 to 55–70 units/g solid for T. virens.

Journal Article

Comparative Proteomics Analysis of Sarcosine Insoluble Outer Membrane Proteins from Clarithromycin Resistant and Sensitive Strains of Helicobacter pylori: Rebecca Smiley , James Bailey , Mahadevan Sethuraman , Norberto Posecion , M. Showkat Ali; J. Microbiol. 2013;51(5):612-618. Published online October 31, 2013; DOI: https://doi.org/10.1007/s12275-013-3029-5

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27 Citations

Abstract: Helicobacter pylori causes disease manifestations in humans including chronic gastric and peptic ulcers, gastric cancer, and lymphoid tissue lymphoma. Increasing rates of H. pylori clarithromycin resistance has led to higher rates of disease development. Because antibiotic resistance involves modifications of outer membrane proteins (OMP) in other Gram-negative bacteria, this study focuses on identification of H. pylori OMP’s using comparative proteomic analyses of clarithromycin-susceptible and -resistant H. pylori strains. Comparative proteomics analyses of isolated sarcosine-insoluble OMP fractions from clarithromycin-susceptible and -resistant H. pylori strains were performed by 1) one dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis protein separation and 2) in-gel digestion of the isolated proteins and mass spectrometry analysis by Matrix Assisted Laser Desorption Ionization-tandem mass spectrometry. Iron-regulated membrane protein, UreaseB, EF-Tu, and putative OMP were down-regulated; HopT (BabB) transmembrane protein, HofC, and OMP31 were up-regulated in clarithromycin-resistant H. pylori. Western blotting and real time PCR, respectively, validated UreaseB subunit and EF-Tu changes at the protein level, and mRNA expression of HofC and HopT. This limited proteomic study provides evidence that alteration of the outer membrane proteins’ profile may be a novel mechanism involved in clarithromycin resistance in H. pylori.

Research Support, N.I.H., Extramural

Free Mycolic Acid Accumulation in the Cell Wall of the mce1 Operon Mutant Strain of Mycobacterium tuberculosis: Sally A. Cantrell , Michael D. Leavell , Olivera Marjanovic , Anthony T. Iavarone , Julie A. Leary , Lee W. Riley; J. Microbiol. 2013;51(5):619-626. Published online September 14, 2013; DOI: https://doi.org/10.1007/s12275-013-3092-y

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51 Citations

Abstract: The lipid-rich cell wall of Mycobacterium tuberculosis, the agent of tuberculosis, serves as an effective barrier against many chemotherapeutic agents and toxic host cell effector molecules, and it may contribute to the mechanism of persistence. Mycobacterium tuberculosis strains mutated in a 13-gene operon called mce1, which encodes a putative ABC lipid transporter, induce aberrant granulomatous response in mouse lungs. Because of the postulated role of the mce1 operon in lipid importation, we compared the cell wall lipid composition of wild type and mce1 operon mutant M. tuberculosis H37Rv strains. High resolution mass spectrometric analyses of the mce1 mutant lipid extracts showed unbound mycolic acids to accumulate in the cell wall. Quantitative analysis revealed a 10.7 fold greater amount of free mycolates in the mutant compared to that of the wild type strain. The free mycolates were comprised of alpha, methoxy and keto mycolates in the ratio 1:0.9:0.6, respectively. Since the mce1 operon is regulated in vivo, the free mycolates that accumulate during infection may serve as a barrier for M. tuberculosis against toxic products and contribute to the pathogen’s persistence.

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

Crystal Structure of XoLAP, a Leucine Aminopeptidase, from Xanthomonas oryzae pv. oryzae: Jin-Kwang Kim , Sampath Natarajan , Hanseul Park , Kim-Hung Huynh , Sang Hee Lee , Jeong-Gu Kim , Yeh-Jin Ahn , Lin-Woo Kang; J. Microbiol. 2013;51(5):627-632. Published online October 31, 2013; DOI: https://doi.org/10.1007/s12275-013-3234-2

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7 Citations

Abstract: Aminopeptidases are metalloproteinases that degrade N-terminal residues from protein and play important roles in cell growth and development by controlling cell homeostasis and protein maturation. We determined the crystal structure of XoLAP, a leucyl aminopeptidase, at 2.6 Å resolution from Xanthomonas oryzae pv. oryzae, causing the destructive rice disease of bacterial blight. It is the first crystal structure of aminopeptidase from phytopathogens as a drug target. XoLAP existed as a hexamer and the monomer structure consisted of an N-terminal cap domain and a C-terminal peptidase domain with two divalent zinc ions. XoLAP structure was compared with BlLAP and EcLAP (EcPepA) structures. Based on the structural comparison, the molecular model of XoLAP in complex with the natural aminopeptidase inhibitor of microginin FR1 was proposed. The model structure will be useful to develop a novel antibacterial drug against Xoo.

Safety Evaluation of Lactobacillus paracasei subsp. paracasei LC-01, Probiotic Bacterium: Hao Zhang , Yu Wang , Jing Sun , Zirui Guo , Huiyuan Guo , Fazheng Ren; J. Microbiol. 2013;51(5):633-638. Published online October 31, 2013; DOI: https://doi.org/10.1007/s12275-013-3336-x

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11 Citations

Abstract: The safety of Lactobacillus paracasei subsp. paracasei LC-01 was evaluated for its use as a potential probiotic. In our in vitro study, the antibiotic resistance and the ability to produce biogenic amine were determined. The results showed that the strain was sensitive to all tested antibiotics and did not produce biogenic amine except for tyramine. The oral toxicity of this strain was evaluated in Balb/C mice. One hundred mice were divided into 10 groups. Four groups were administered 0, 108, 109, or 1010 CFU/mouse per day dissolved in saline solution respectively, for 28 days. Three groups were injected intraperitoneally with 109 CFU/mouse dissolved in saline solution, and were killed 2, 5, and 10 days after injection. The last 3 groups were injected with the vehicle as controls respectively. The results showed that oral administration of the strain had no adverse effects on mouse body weight and that there was no treatment-associated bacterial translocation. Intraperitoneal administration caused a significant translocation to liver, spleen and kidney. However, this translocation did not cause illness or death throughout the experiment. The results suggest that L. paracasei subsp. paracasei LC-01 is likely to be safe for human consumption.

Experimental Phasing Using Zinc and Sulfur Anomalous Signals Measured at the Zinc Absorption Peak: Sangmin Lee , Min-Kyu Kim , Chang-Jun Ji , Jin-Won Lee , Sun-Shin Cha; J. Microbiol. 2013;51(5):639-643. Published online October 31, 2013; DOI: https://doi.org/10.1007/s12275-013-3412-2

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Abstract: Iron is an essential transition metal required for bacterial growth and survival. Excess free iron can lead to the generation of reactive oxygen species that can cause severe damage to cellular functions. Cells have developed iron-sensing regulators to maintain iron homeostasis at the transcription level. The ferric uptake regulator (Fur) is an iron-responsive regulator that controls the expression of genes involved in iron homeostasis, bacterial virulence, stress resistance, and redox metabolism. Here, we report the expression, purification, crystallization, and phasing of the apo-form of Bacillus subtilis Fur (BsFur) in the absence of regulatory metal ions. Crystals were obtained by microbatch crystallization method at 295 K and diffraction data at a resolution of 2.6 Å was collected at the zinc peak wavelength (λ=1.2823 Å). Experimental phasing identified the positions of one zinc atom and four sulfur atoms of cysteine residues coordinating the zinc atom, indicating that the data contained a meaningful anomalous scattering originating from the ordered zinc-coordinating sulfur atoms, in spite of the small anomalous signals of sulfur atoms at the examined wavelength.

Involvement of Phosphatidylinositol 3-Kinase/Akt Signaling Pathway in β1 Integrin-Mediated Internalization of Staphylococcus aureus by Alveolar Epithelial Cells: Jia-He Wang , Ke Zhang , Nan Wang , Xiao-Min Qiu , Yi-Bing Wang , Ping He; J. Microbiol. 2013;51(5):644-650. Published online June 25, 2013; DOI: https://doi.org/10.1007/s12275-013-3040-x

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20 Citations

Abstract: The invasion of Staphylococcus aureus into alveolar epithelial cells is regarded as the key step for S. aureus lung infection. However, the mechanism of internalization of S. aureus by alveolar epithelial cells is not clear, and was the aim of this investigation Human lung adenocarcinomic epithelial cells and A549 cells were used. Human β1 integrin and rat β1 integrin were detected by real-time reverse transcription (RT)-PCR. The expressions of β1 integrin, Akt and p-Akt were detected by Western blot analysis. To further investigate the role of β1 integrin in S. aureus internalization by alveolar epithelial cells, we next performed siRNA-mediated knockdown of β1 integrin expression. In this study, we found that S. aureus invades human alveolar epithelial cells and rat primary alveolar epithelial cells. The β1 integrin ligand competitive inhibitor, GRGDS-peptide, blocked the internalization of S. aureus by A549 cells. Knockdown of β1 integrin also inhibited the internalization of S. aureus. In addition, the PI3K/Akt signaling pathway in alveolar epithelial cells was activated by the infection with S. aureus. Furthermore, Akt phosphorylation was abolished by transient transfection with β1 integrin siRNA in A549 cells challenged with S. aureus. Our results suggest that the phosphatidylinositol 3-kinase/Akt signaling pathway plays an important role in β1 integrin-mediated internalization of S. aureus by alveolar epithelial cells.

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