Journal of Microbiology

Journal Articles

Tubulysin Production by the Dead Cells of Archangium gephyra KYC5002.: Seohui Park, Chaehyeon Park, Yujin Ka, Kyungyun Cho; J. Microbiol. 2024;62(6):463-471. Published online June 13, 2024; DOI: https://doi.org/10.1007/s12275-024-00130-3

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Abstract: Archangium gephyra KYC5002 produces tubulysins during the death phase. In this study, we aimed to determine whether dead cells produce tubulysins. Cells were cultured for three days until the verge of the death phase, disrupted via ultrasonication, incubated for 2 h, and examined for tubulysin production. Non-disrupted cells produced 0.14 mg/L of tubulysin A and 0.11 mg/L of tubulysin B. Notably, tubulysin A production was increased by 4.4-fold to 0.62 mg/L and that of tubulysin B was increased by 6.7-fold to 0.74 mg/L in the disrupted cells. The same increase in tubulysin production was observed when the cells were killed by adding hydrogen peroxide. However, when the enzymes were inactivated via heat treatment of the cultures at 65 °C for 30 min, no significant increase in tubulysin production due to cell death was observed. Reverse transcription-quantitative polymerase chain reaction analysis of tubB mRNA revealed that the expression levels of tubulysin biosynthetic enzyme genes increased during the death phase compared to those during the vegetative growth phase. Our findings suggest that A. gephyra produces biosynthetic enzymes and subsequently uses them for tubulysin production in the cell death phase or during cell lysis by predators.

In Silico Intensive Analysis for the E4 Gene Evolution of Human Adenovirus Species D.: Chanhee Lee, Anyeseu Park, Jeong Yoon Lee; J. Microbiol. 2024;62(5):409-418. Published online April 30, 2024; DOI: https://doi.org/10.1007/s12275-024-00132-1

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Abstract: Adenovirus (Ad) is a ubiquitous pathogen capable of infecting a wide range of animals and humans. Human Adenovirus (HAdV) can cause severe infection, particularly in individuals with compromised immune systems. To date, over 110 types of HAdV have been classified into seven species from A to G, with the majority belonging to the human adenovirus species D (HAdV-D). In the HAdV-D, the most significant factor for the creation of new adenovirus types is homologous recombination between viral genes involved in determining the virus tropism or evading immune system of host cells. The E4 gene, consisting of seven Open Reading Frames (ORFs), plays a role in both the regulation of host cell metabolism and the replication of viral genes. Despite long-term studies, the function of each ORF remains unclear. Based on our updated information, ORF2, ORF3, and ORF4 have been identified as regions with relatively high mutations compared to other ORFs in the E4 gene, through the use of in silico comparative analysis. Additionally, we managed to visualize high mutation sections, previously undetectable at the DNA level, through a powerful amino acid sequence analysis tool known as proteotyping. Our research has revealed the involvement of the E4 gene in the evolution of human adenovirus, and has established accurate sequence information of the E4 gene, laying the groundwork for further research.

Transcriptome‑based Mining of the Constitutive Promoters for Tuning Gene Expression in Aspergillus oryzae: Kobkul Laoteng , Jutamas Anantayanon , Chanikul Chutrakul , Sarocha Panchanawaporn , Sukanya Jeennor; J. Microbiol. 2023;61(2):199-210. Published online February 6, 2023; DOI: https://doi.org/10.1007/s12275-023-00020-0

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Abstract: Transcriptional regulation has been adopted for developing metabolic engineering tools. The regulatory promoter is a crucial genetic element for strain optimization. In this study, a gene set of Aspergillus oryzae with highly constitutive expression across different growth stages was identified through transcriptome data analysis. The candidate promoters were functionally characterized in A. oryzae by transcriptional control of β-glucuronidase (GUS) as a reporter. The results showed that the glyceraldehyde triphosphate dehydrogenase promoter (PgpdA1) of A. oryzae with a unique structure displayed the most robust strength in constitutively controlling the expression compared to the PgpdA2 and other putative promoters tested. In addition, the ubiquitin promoter (Pubi) of A. oryzae exhibited a moderate expression strength. The deletion analysis revealed that the 5' untranslated regions of gpdA1 and ubi with the length of 1028 and 811 nucleotides, counted from the putative translation start site (ATG), respectively, could efficiently drive the GUS expression. Interestingly, both promoters could function on various carbon sources for cell growth. Glucose was the best fermentable carbon source for allocating high constitutive expressions during cell growth, and the high concentrations (6–8% glucose, w/v) did not repress their functions. It was also demonstrated that the secondary metabolite gene coding for indigoidine could express under the control of PgpdA1 or Pubi promoter. These strong and moderate promoters of A. oryzae provided beneficial options in tuning the transcriptional expression for leveraging the metabolic control towards the targeted products.

Flavihumibacter fluminis sp. nov. and Flavihumibacter rivuli sp. nov., isolated from a freshwater stream: Miri S. Park , Hyeonuk Sa , Ilnam Kang , Jang-Cheon Cho; J. Microbiol. 2022;60(8):806-813. Published online July 29, 2022; DOI: https://doi.org/10.1007/s12275-022-2298-2

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Abstract: Two Gram-stain-positive, aerobic, chemoheterotrophic, nonmotile, rod-shaped, and yellow-pigmented bacterial strains, designated IMCC34837T and IMCC34838T, were isolated from a freshwater stream. Results of 16S rRNA gene-based phylogenetic analyses showed that strains IMCC34837T and IMCC- 34838T shared 96.3% sequence similarity and were most closely related to Flavihumibacter profundi Chu64-6-1T (99.6%) and Flavihumibacter cheonanensis WS16T (96.4%), respectively. Complete whole-genome sequences of strains IMCC- 34837T and IMCC34838T were 5.0 Mbp and 4.3 Mbp of genome size with 44.5% and 47.9% of DNA G + C contents, respectively. Average nucleotide identity (ANI) and digital DNA- DNA hybridization (dDDH) values between the two strains were 70.0% and 17.9%, repectively, revealing that they are independent species. The two strains showed ≤ 75.2% ANI and ≤ 19.3% dDDH values to each closely related species of the genus Flavihumibacter, indicating that the two strains represent each novel species. Major fatty acid constituents of strain IMCC34837T were iso-C15:0, iso-C15:1 G and anteiso-C15:0 and those of strain IMCC34838T were iso-C15:0 and iso-C15:1 G. The predominant isoprenoid quinone detected in both strains was menaquinone-7 (MK-7). Major polar lipids of both strains were phosphatidylethanolamine, aminolipids, and glycolipids. Based on the phylogenetic and phenotypic characterization, strains IMCC34837T and IMCC34838T were considered to represent two novel species within the genus Flavihumibacter, for which the names Flavihumibacter fluminis sp. nov. and Flavihumibacter rivuli sp. nov. are proposed with IMCC34837T (= KACC 21752T = NBRC 115292T) and IMCC34838T (= KACC 21753T = NBRC 115293T) as the type strains, respectively.

Regulatory role of cysteines in (2R, 3R)-butanediol dehydrogenase BdhA of Bacillus velezensis strain GH1-13: Yunhee Choi , Yong-Hak Kim; J. Microbiol. 2022;60(4):411-418. Published online March 14, 2022; DOI: https://doi.org/10.1007/s12275-022-2018-y

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Abstract: Bacillus velezensis strain GH1-13 contains a (2R,3R)-butanediol dehydrogenase (R-BDH) BdhA which converts acetoin to R-BD reversibly, however, little is known about its regulatory cysteine and biological significance. We performed sitedirected mutation of three cysteines in BdhA. The C37S mutant had no enzyme activity and the C34S and C177S mutants differed from each other and wild type (WT). After zinc affinity chromatography, 1 mM ZnCl2 treatment resulted in a 3-fold enhancement of the WT activity, but reduced activity of the C34S mutant by more than 2 folds compared to the untreated ones. However, ZnCl2 treatment did not affect the activity of the C177S mutant. Most of the double and triple mutant proteins (C34S/C37S, C34S/C177S, C37S/C177S, and C34S/C37S/C177S) were aggregated in zinc resins, likely due to the decreased protein stability. All of the purified WT and single mutant proteins increased multiple intermolecular disulfide bonds in the presence of H2O2 as the buffer pH decreased from 7.5 to 5.5, whereas an intramolecular disulfide bond of cysteine 177 and another cysteine in the CGIC motif region was likely formed at pH higher than pKa of 7.5. When pH varied, WT and its C34S or C177S mutants reduced acetoin to R-BD at the optimum pH 5.5 and oxidized R-BD to acetoin at the optimum pH 10. This study demonstrated that cysteine residues in BdhA play a regulatory role for the production of acetoin and R-BD depending on pH as well as metal binding and oxidative stress.

Activity of Lactobacillus crispatus isolated from vaginal microbiota against Mycobacterium tuberculosis: Youngkyoung Lee , Hoonhee Seo , Sukyung Kim Abdur Rahim , Youjin Yoon , Jehee Jung , Saebim Lee , Chang Beom Ryu , Ho-Yeon Song; J. Microbiol. 2021;59(11):1019-1030. Published online November 1, 2021; DOI: https://doi.org/10.1007/s12275-021-1332-0

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9 Citations

Abstract: Tuberculosis, an infectious disease, is caused by Mycobacterium tuberculosis. It remains a significant public health issue around the globe, causing about 1.8 million deaths every year. Drug-resistant M. tuberculosis, including multi-drug-resistant (MDR), extremely-drug-resistant (XDR), and totally drugresistant (TDR) M. tuberculosis, continues to be a threat to public health. In the case of antibiotic-resistant tuberculosis, the treatment effect of conventional antibiotics is low. Side effects caused by high doses over a long period are causing severe problems. To overcome these problems, there is an urgent need to develop a new anti-tuberculosis drug that is different from the existing compound-based antibiotics. Probiotics are defined as live microorganisms conferring health benefits. They can be potential therapeutic agents in this context as the effectiveness of probiotics against different infectious diseases has been well established. Here, we report that Lactobacillus crispatus PMC201 shows a promising effect on tuberculosis isolated from vaginal fluids of healthy Korean women. Lactobacillus crispatus PMC201 reduced M. tuberculosis H37Rv under co-culture conditions in broth and reduced M. tuberculosis H37Rv and XDR M. tuberculosis in macrophages. Lactobacillus crispatus PMC201 was not toxic to a guinea pig model and did not induce dysbiosis in a human intestinal microbial ecosystem simulator. Taken together, these
results
indicate that L. crispatus PMC201 can be a promising alternative drug candidate in the current tuberculosis drug regime. Further study is warranted to assess the in vivo efficacy and confirm the mode of action of L. crispatus PMC201.

Salmonella Typhimurium ST313 isolated in Brazil revealed to be more invasive and inflammatory in murine colon compared to ST19 strains: Amanda Aparecida Seribelli , Tamara R. Machado Ribeiro , Patrick da Silva† , Isabela Mancini Martins , Felipe Pinheiro Vilela , Marta I. Cazentini Medeiros , Kamila Chagas Peronni , Wilson Araújo da Silva Junior , Cristiano Gallina Moreira , Juliana Pfrimer Falcão; J. Microbiol. 2021;59(9):861-870. Published online August 12, 2021; DOI: https://doi.org/10.1007/s12275-021-1082-z

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Abstract: Salmonella Typhimurium (ST313) has caused an epidemic of invasive disease in sub-Saharan Africa and has been recently identified in Brazil. As the virulence of this ST is poorly understood, the present study aimed to (i) perform the RNAseq in vitro of S. Typhimurium STm30 (ST313) grown in Luria-Bertani medium at 37°C; (ii) compare it with the RNAseq of the S. Typhimurium SL1344 (ST19) and S. Typhimurium STm11 (ST19) strains under the same growing conditions; and (iii) examine the colonization capacity and expression of virulence genes and cytokines in murine colon. The STm30 (ST313) strain exhibited stronger virulence and was associated with a more inflammatory profile than the strains SL1344 (ST19) and STm11 (ST19), as demonstrated by transcriptome and in vivo assay. The expression levels of the hilA, sopD2, pipB, and ssaS virulence genes, other Salmonella pathogenicity islands SPI-1 and SPI-2 genes or effectors, and genes of the cytokines IL-1β, IFN-γ, TNF-α, IL-6, IL-17, IL-22, and IL-12 were increased during ST313 infection in C57BL/6J mice. In conclusion, S. Typhimurium STm30 (ST313) isolated from human feces in Brazil express higher levels of pathogenesis- related genes at 37°C and has stronger colonization and invasion capacity in murine colon due to its high expression levels of virulence genes, when compared with the S. Typhimurium SL1344 (ST19) and STm11 (ST19) strains. STm30 (ST313) also induces stronger expression of pro-inflammatory cytokines in this organ, suggesting that it causes more extensive tissue damage.

Zinc-binding domain mediates pleiotropic functions of Yvh1 in Cryptococcus neoformans: Jae-Hyung Jin , Myung Kyung Choi , Hyun-Soo Cho , Yong-Sun Bahn; J. Microbiol. 2021;59(7):658-665. Published online July 1, 2021; DOI: https://doi.org/10.1007/s12275-021-1287-1

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Abstract: Yvh1 is a dual-specificity phosphatase (DUSP) that is evolutionarily conserved in eukaryotes, including yeasts and humans. Yvh1 is involved in the vegetative growth, differentiation, and virulence of animal and plant fungal pathogens. All Yvh1 orthologs have a conserved DUSP catalytic domain at the N-terminus and a zinc-binding (ZB) domain with two zinc fingers (ZFs) at the C-terminus. Although the DUSP domain is implicated in the regulation of MAPK signaling in humans, only the ZB domain is essential for most cellular functions of Yvh1 in fungi. This study aimed to analyze the functions of the DUSP and ZB domains of Yvh1 in the human fungal pathogen Cryptococcus neoformans, whose Yvh1 (CnYvh1) contains a DUSP domain at the C-terminus and a ZB domain at the N-terminus. Notably, CnYvh1 has an extended internal domain between the two ZF motifs in the ZB domain. To elucidate the function of each domain, we constructed individual domain deletions and swapping strains by complementing the yvh1Δ mutant with wild-type (WT) or mutated YVH1 alleles and examined their Yvh1-dependent phenotypes, including growth under varying stress conditions, mating, and virulence factor production. Here, we found that the complementation of the yvh1Δ mutant with the mutated YVH1 alleles having two ZFs of the ZB domain, but not the DUSP and extended internal domains, restored the WT phenotypic traits in the yvh1Δ mutant. In conclusion, the ZB domain, but not the N-terminal DUSP domain, plays a pivotal role in the pathobiological functions of cryptococcal Yvh1.

Deep convolutional neural network: a novel approach for the detection of Aspergillus fungi via stereomicroscopy: Haozhong Ma , Jinshan Yang , Xiaolu Chen , Xinyu Jiang , Yimin Su , Shanlei Qiao , Guowei Zhong; J. Microbiol. 2021;59(6):563-572. Published online March 29, 2021; DOI: https://doi.org/10.1007/s12275-021-1013-z

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Abstract: Fungi of the genus Aspergillus are ubiquitously distributed in nature, and some cause invasive aspergillosis (IA) infections in immunosuppressed individuals and contamination in agricultural products. Because microscopic observation and molecular detection of Aspergillus species represent the most operator-dependent and time-intensive activities, automated and cost-effective approaches are needed. To address this challenge, a deep convolutional neural network (CNN) was used to investigate the ability to classify various Aspergillus species. Using a dissecting microscopy (DM)/stereomicroscopy platform, colonies on plates were scanned with a 35× objective, generating images of sufficient resolution for classification. A total of 8,995 original colony images from seven Aspergillus species cultured in enrichment medium were gathered and autocut to generate 17,142 image crops as training and test datasets containing the typical representative morphology of conidiophores or colonies of each strain. Encouragingly, the Xception model exhibited a classification accuracy of 99.8% on the training image set. After training, our CNN model achieved a classification accuracy of 99.7% on the test image set. Based on the Xception performance during training and testing, this classification algorithm was further applied to recognize and validate a new set of raw images of these strains, showing a detection accuracy of 98.2%. Thus, our study demonstrated a novel concept for an artificial-intelligence-based and cost-effective detection
method
ology for Aspergillus organisms, which also has the potential to improve the public’s understanding of the fungal kingdom.

Antarctic tundra soil metagenome as useful natural resources of cold-active lignocelluolytic enzymes: Han Na Oh , Doyoung Park , Hoon Je Seong , Dockyu Kim , Woo Jun Sul; J. Microbiol. 2019;57(10):865-873. Published online September 30, 2019; DOI: https://doi.org/10.1007/s12275-019-9217-1

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Abstract: Lignocellulose composed of complex carbohydrates and aromatic heteropolymers is one of the principal materials for the production of renewable biofuels. Lignocellulose-degrading genes from cold-adapted bacteria have a potential to increase the productivity of biological treatment of lignocellulose biomass by providing a broad range of treatment temperatures. Antarctic soil metagenomes allow to access novel genes encoding for the cold-active lignocellulose-degrading enzymes, for biotechnological and industrial applications. Here, we investigated the metagenome targeting cold-adapted microbes in Antarctic organic matter-rich soil (KS 2-1) to mine lignolytic and celluloytic enzymes by performing single molecule, real-time metagenomic (SMRT) sequencing. In the assembled Antarctic metagenomic contigs with relative long reads, we found that 162 (1.42%) of total 11,436 genes were annotated as carbohydrate-active enzymes (CAZy). Actinobacteria, the dominant phylum in this soil’s metagenome, possessed most of candidates of lignocellulose catabolic genes like glycoside hydrolase families (GH13, GH26, and GH5) and auxiliary activity families (AA7 and AA3). The predicted lignocellulose degradation pathways in Antarctic soil metagenome showed synergistic role of various CAZyme harboring bacterial genera including Streptomyces, Streptosporangium, and Amycolatopsis. From phylogenetic relationships with cellular and environmental enzymes, several genes having potential for participating in overall lignocellulose degradation were also found. The results indicated the presence of lignocellulose-degrading bacteria in Antarctic tundra soil and the potential benefits of the lignocelluolytic enzymes as candidates for cold-active enzymes which will be used for the future biofuel-production industry.

Alcohol dehydrogenase 1 participates in the Crabtree effect and connects fermentative and oxidative metabolism in the Zygomycete Mucor circinelloides: Rosa Angélica Rangel-Porras , Sharel P. Díaz-Pérez , Juan Manuel Mendoza-Hernández , Pamela Romo-Rodríguez , Viridiana Alejandre-Castañeda , Marco I Valle-Maldonado , Juan Carlos Torres-Guzmán , Gloria Angélica González-Hernández , Jesús Campos-Garcia , José Arnau , Víctor Meza-Carmen , J. Félix Gutiérrez-Corona; J. Microbiol. 2019;57(7):606-617. Published online June 27, 2019; DOI: https://doi.org/10.1007/s12275-019-8680-z

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Abstract: Mucor circinelloides is a dimorphic Zygomycete fungus that produces ethanol under aerobic conditions in the presence of glucose, which indicates that it is a Crabtree-positive fungus. To determine the physiological role of the alcohol dehydrogenase (ADH) activity elicited under these conditions, we obtained and characterized an allyl alcohol-resistant mutant that was defective in ADH activity, and examined the effect of adh mutation on physiological parameters related to carbon and energy metabolism. Compared to the Adh+ strain R7B, the ADH-defective (Adh-) strain M5 was unable to grow under anaerobic conditions, exhibited a considerable reduction in ethanol production in aerobic cultures when incubated with glucose, had markedly reduced growth capacity in the presence of oxygen when ethanol was the sole carbon source, and exhibited very low levels of NAD+-dependent alcohol dehydrogenase activity in the cytosolic fraction. Further characterization of the M5 strain showed that it contains a 10-bp deletion that interrupts the coding region of the adh1 gene. Complementation with the wild-type allele adh1+ by transformation of M5 remedied all the defects caused by the adh1 mutation. These findings indicate that in M. circinelloides, the product of the adh1 gene mediates the Crabtree effect, and can act as either a fermentative or an oxidative enzyme, depending on the nutritional conditions, thereby participating in the association between fermentative and oxidative metabolism. It was found that the spores of M. circinelloides possess low mRNA levels of the ethanol assimilation genes (adl2 and acs2), which could explain their inability to grow in the alcohol.

Oxygen-mediated growth enhancement of an obligate anaerobic archaeon Thermococcus onnurineus NA1: Seong Hyuk Lee , Hwan Youn , Sung Gyun Kang , Hyun Sook Lee; J. Microbiol. 2019;57(2):138-142. Published online January 31, 2019; DOI: https://doi.org/10.1007/s12275-019-8592-y

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Abstract: Thermococcus onnurineus NA1, an obligate anaerobic hyperthermophilic archaeon, showed variable oxygen (O2) sensitivity depending on the types of substrate employed as an energy source. Unexpectedly, the culture with yeast extract as a sole energy source showed enhanced growth by 2-fold in the presence of O2. Genome-wide transcriptome analysis revealed the upregulation of several antioxidant-related genes encoding thioredoxin peroxidase (TON_0862), rubrerythrin (TON_0864), rubrerythrin-related protein (TON_0873), NAD(P)H rubredoxin oxidoreductase (TON_0865), or thioredoxin reductase (TON_1603), which can couple the detoxification of reactive oxygen species with the regeneration of NAD(P)+ from NAD(P)H. We present a plausible mechanism by which O2 serves to maintain the intracellular redox balance. This study demonstrates an unusual strategy of an obligate anaerobe underlying O2-mediated growth enhancement despite not having heme-based or cytochrome-type proteins.

Temporal and spatial impact of Spartina alterniflora invasion on methanogens community in Chongming Island, China: Xue Ping Chen , Jing Sun , Yi Wang , Heng Yang Zhang , Chi Quan He , Xiao Yan Liu , Nai Shun Bu , Xi-En Long; J. Microbiol. 2018;56(7):507-515. Published online June 14, 2018; DOI: https://doi.org/10.1007/s12275-018-8062-y

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Abstract: Methane production by methanogens in wetland is recognized as a significant contributor to global warming. Spartina alterniflora (S. alterniflora), which is an invasion plant in China’s wetland, was reported to have enormous effects on methane production. But studies on shifts in the methanogen community in response to S. alterniflora invasion at temporal and spatial scales in the initial invasion years are rare. Sediments derived from the invasive species S. alterniflora and the native species Phragmites australis (P. australis) in pairwise sites and an invasion chronosequence patch (4 years) were analyzed to investigate the abundance and community structure of methanogens using quantitative real-time PCR (qPCR) and Denaturing gradient gel electrophoresis (DGGE) cloning of the methyl-coenzyme M reductase A (mcrA) gene. For the pairwise sites, the abundance of methanogens in S. alterniflora soils was lower than that of P. australis soils. For the chronosequence patch, the abundance and diversity of methanogens was highest in the soil subjected to two years invasion, in which we detected some rare groups including Methanocellales and Methanococcales. These results indicated a priming effect at the initial invasion stages of S. alterniflora for microorganisms in the soil, which was also supported by the diverse root exudates. The shifts of methanogen communities after S. alterniflora invasion were due to changes in pH, salinity and sulfate. The results indicate that root exudates from S. alterniflora have a priming effect on methanogens in the initial years after invasion, and the predominate methylotrophic groups (Methanosarcinales) may adapt to the availability of diverse substrates and reflects the potential for high methane production after invasion by S. alterniflora.

Photosynthetic and biochemical responses of the freshwater green algae Closterium ehrenbergii Meneghini (Conjugatophyceae) exposed to the metal coppers and its implication for toxicity testing: Hui Wang , Vinitha Ebenezer , Jang-Seu Ki; J. Microbiol. 2018;56(6):426-434. Published online June 1, 2018; DOI: https://doi.org/10.1007/s12275-018-8081-8

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26 Citations

Abstract: The freshwater green algae Closterium is sensitive to water quality, and hence has been suggested as ideal organisms for toxicity testing. In the present study, we evaluated the photosynthetic and biochemical responses of C. ehrenbergii to the common contaminants, coppers. The 72 h median effective concentrations (EC50) of CuSO4 and CuCl2 on the test organism were calculated to be 0.202 mg/L and 0.245 mg/L, respectively. Exposure to both coppers considerably decreased pigment levels and photosynthetic efficiency, while inducing the generation of reactive oxygen species (ROS) in cells with increased exposure time. Moreover, the coppers significantly increased the levels of lipid peroxidation and superoxide dismutase (SOD) activity, even at relatively lower concentrations. These suggest that copper contaminants may exert deleterious effects on the photosynthesis and cellular oxidative stress of C. ehrenbergii, representing its powerful potential in aquatic toxicity assessments.

Hydrogen sulfide inhibits the growth of Escherichia coli through oxidative damage: Liu-Hui Fu , Zeng-Zheng Wei , Kang-Di Hu , Lan-Ying Hu , Yan-Hong Li , Xiao-Yan Chen , Zhuo Han , Gai-Fang Yao , Hua Zhang; J. Microbiol. 2018;56(4):238-245. Published online February 28, 2018; DOI: https://doi.org/10.1007/s12275-018-7537-1

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59 Citations

Abstract: Many studies have shown that hydrogen sulfide (H2S) is both detrimental and beneficial to animals and plants, whereas its effect on bacteria is not fully understood. Here, we report that H2S, released by sodium hydrosulfide (NaHS), significantly inhibits the growth of Escherichia coli in a dose-dependent manner. Further studies have shown that H2S treatment stimulates the production of reactive oxygen species (ROS) and decreases glutathione (GSH) levels in E. coli, resulting in lipid peroxidation and DNA damage. H2S also inhibits the antioxidative enzyme activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) and induces the response of the SoxRS and OxyR regulons in E. coli. Moreover, pretreatment with the antioxidant ascorbic acid (AsA) could effectively prevent H2S-induced toxicity in E. coli. Taken together, our results indicate that H2S exhibits an antibacterial effect on E. coli through oxidative damage and suggest a possible application for H2S in water and food processing.

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