Journal of Microbiology

Journal Articles

Gut Lactobacillus and Probiotics Lactobacillus lactis/rhamnosis Ameliorate Liver Fibrosis in Prevention and Treatment: Sung Min Won , Na Young Lee , Ki&# , Haripriya Gupta , Satya Priya Sharma , Kyung Hwan Kim , Byoung Kook Kim , Hyun Chae Joung , Jin Ju Jeong , Raja Ganesan , Sang Hak Han , Sang Jun Yoon , Dong Joon Kim , Ki Tae Suk; J. Microbiol. 2023;61(2):245-257. Published online February 6, 2023; DOI: https://doi.org/10.1007/s12275-023-00014-y

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Abstract: The progression and exacerbation of liver fibrosis are closely related to the gut microbiome. It is hypothesized that some probiotics may slow the progression of liver fibrosis. In human stool analysis [healthy group (n = 44) and cirrhosis group (n = 18)], difference in Lactobacillus genus between healthy group and cirrhosis group was observed. Based on human data, preventive and therapeutic effect of probiotics Lactobacillus lactis and L. rhamnosus was evaluated by using four mice fibrosis models. L. lactis and L. rhamnosus were supplied to 3,5-diethoxycarbonyl-1,4-dihydrocollidine or carbon tetrachloride-induced liver fibrosis C57BL/6 mouse model. Serum biochemical measurements, tissue staining, and mRNA expression in the liver were evaluated. The microbiome was analyzed in mouse cecal contents. In the mouse model, the effects of Lactobacillus in preventing and treating liver fibrosis were different for each microbe species. In case of L. lactis, all models showed preventive and therapeutic effects against liver fibrosis. In microbiome analysis in mouse models administered Lactobacillus, migration and changes in the ratio and composition of the gut microbial community were confirmed. L. lactis and L. rhamnosus showed preventive and therapeutic effects on the progression of liver fibrosis, suggesting that Lactobacillus intake may be a useful strategy for prevention and treatment.

Pikeienuella piscinae gen. nov., sp. nov., a novel genus in the family Rhodobacteraceae: Jeeeun Park , Young-Sam Kim , Seong-Jin Kim , Sang-Eon Kim , Hyun-Kyoung Jung , Min-Ju Yu , Young Jae Jeon , Kyoung-Ho Kim; J. Microbiol. 2021;59(6):546-551. Published online April 20, 2021; DOI: https://doi.org/10.1007/s12275-021-0678-7

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Abstract: A novel bacterium, designated strain RR4-56T, was isolated from a biofilter of a seawater recirculating aquaculture system. The 16S rRNA gene sequence analysis showed that the isolate was closely related to Halovulum dunhuangense YYQ- 30T (92.6%), Albimonas donghaensis DS2T (91.3%), Pontivivens insulae GYSW-23T (91.3%), and Monaibacterium marinum C7T (90.9%), belonging to the family Rhodobacteraceae. The strain was aerobic, Gram-negative, rod-shaped, oxidasepositive, and catalase-negative. Its optimum temperature, pH, and salinity for growth were 25–30°C, pH 8.5, and 2–3% NaCl (w/v), respectively. Its growth occurred at 15–35°C, pH 5.0–9.5, and 0–7% NaCl (w/v). It contained ubiquinone-10 (Q-10), a respiratory quinone, and the major cellular fatty acids were 11-methyl C18:1 ω7c (31.9%), C18:1 ω6c (30.4%), and C19:0 cyclo ω8c (16.1%). The polar lipids present in the strain were phosphatidylglycerol, an unidentified phospholipid, and an unidentified aminolipid. The strain had one 4,373,045 bp circular chromosome with G + C contents of 65.9 mol% including 4,169 genes, 4,118 coding sequences (CDSs), 3 rRNAs, and 45 tRNAs. Genome annotation predicted some gene clusters related to the degradation of several types of organic matter such as protocatechuate, catechol, and phthalate. Based on the polyphasic characteristics, RR4-56T represents a novel genus and species in the family Rhodobacteraceae, for which the name Pikeienuella piscinae gen. nov., sp. nov. was proposed. The type strain is RR4-56T (= KCTC 52648T = DSM 107918T).

Paenibacillus psychroresistens sp. nov., isolated from the soil of an Arctic glacial retreat: In-Tae Cha , Eui-Sang Cho , Yoo Kyung Lee , Seong Woon Roh , Myung-Ji Seo; J. Microbiol. 2019;57(7):569-574. Published online June 27, 2019; DOI: https://doi.org/10.1007/s12275-019-8666-x

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Abstract: Strain ML311-T8T was isolated from a glacial retreat area in Svalbard, Norway, and was taxonomically characterized by a polyphasic approach. Upon phylogenetic analysis, strain ML311-T8T was clustered with Paenibacillus arcticus MME2_ R6T and P. contaminans CKOBP-6T with 98.3–98.6 and 93.5– 93.9% 16S rRNA gene sequence similarities, respectively. DNA-DNA hybridization values between strain ML311-T8T and P. arcticus MME2_R6T was 19.9%. The genomic DNA G+C content was 41.1 mol%. The isolated strain was Gramstain- positive, strictly aerobic and rod-shaped, and grew in 0–0.5% (w/v) NaCl, at 4–23°C and pH 6.0–10.0, with optimal growth in 0% (w/v) NaCl, at 20°C and pH 7.0–8.0. The predominant respiratory quinone of strain ML311-T8T was MK- 7 and the major fatty acids were anteiso-C15:0 and C16:0. The polar lipids of strain ML311-T8T were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, three unidentified amino lipids, and three unidentified lipids. On the basis of polyphasic taxonomic analysis, the strain ML311-T8T is proposed to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus psychroresistens sp. nov. is proposed. The type strain is ML311-T8T (= KCCM 43190T = JCM 31243T).

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

NOTE] A Simple and Reliable Method for Obtaining Entomosporium Monoconidial Isolates: Mi-Jeong Park , Quinn A. Holtslag , Hyeon-Dong Shin; J. Microbiol. 2011;49(2):324-326. Published online May 3, 2011; DOI: https://doi.org/10.1007/s12275-011-1117-y

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Abstract: Monoconidial isolates of Entomosporium mespili were successfully cultured using a simple isolation procedure. A detailed description of the steps required for isolating E. mespili is provided. The characteristic pattern of conidial germination and growth on potato dextrose agar is also described. The process that was successful in obtaining pure isolates involved collecting material in the morning, picking a glistening white mass of conidia under dissecting microscope magnification, depositing a mass of conidia onto a drop of water on a glass slide, streaking the conidial mass onto potato dextrose agar, incubating the plate for 48 h, and transferring the characteristic fan-shaped colonies to fresh medium.

Prevalence of Tetracycline Resistance Genes in Greek Seawater Habitats: Theodora L. Nikolakopoulou , Eleni P. Giannoutsou , Adamandia A. Karabatsou , Amalia D. Karagouni; J. Microbiol. 2008;46(6):633-640. Published online December 24, 2008; DOI: https://doi.org/10.1007/s12275-008-0080-8

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Abstract: The presence of selected tetracycline resistance (TcR) genes was studied in different Greek seawater habitats, originated from wastewater treatment facilities, fishfarm, and coastal environments. The methods employed included assessment of the presence of twelve gene clusters by PCR, followed by hybridization with specific probes, in habitat extracted DNA, TcR bacteria, and exogenous isolated plasmids conferring TcR. The direct DNA-based analysis showed that tet(Α) and tet(K) genes were detected in all habitats, whilst tet(C) and tet(E) were present in fishfarm and wastewater effluent samples and tet(M) was detected in fishfarm and coastal samples. Resistance genes tet(A), tet(C), tet(K), and tet(M) were detected in 60 of the 89 isolates screened. These isolates were identified by fatty acid methyl ester analysis (FAME) as Stenotrophomonas, Acinetobacter, Pseudomonas, Bacillus, and Staphylococcus strains. The presence of the TcR genes in 15% of the bacterial isolates coincided with the presence of IncP plasmids. A habitat-specific dissemination of IncP alpha plasmids in wastewater effluent isolates and of IncP beta plasmids in fishfarm isolates was observed. Exogenous isolation demonstrated the presence of plasmids harbouring TcR genes in all the habitats tested. Plasmids were shown to carry tet(A), tet(C), tet(E), and tet(K) genes. It is concluded that TcR genes are widespread in the seawater habitats studied and often occur on broad host range plasmids that seem to be well disseminated in the bacterial communities.

A Culture-Based Study of the Bacterial Communities within the Guts of Nine Longicorn Beetle Species and their Exo-enzyme Producing Properties for Degrading Xylan and Pectin: Doo-Sang Park , Hyun-Woo Oh , Won-Jin Jeong , Hyangmi Kim , Ho-Yong Park , Kyung Sook Bae; J. Microbiol. 2007;45(5):394-401.; DOI: https://doi.org/2598 [pii]

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Abstract: In this study, bacterial communities within the guts of several longicorn beetles were investigated by a culture-dependent method. A total of 142 bacterial strains were isolated from nine species of longicorn beetle, including adults and larvae. A comparison of their partial 16S rRNA gene sequences showed that most of the bacteria constituting the gut communities can typically be found in soil, plants and the intestines of animals, and approximately 10% were proposed as unreported. Phylogenetic analysis demonstrated that the bacterial species comprised 7 phyla, and approximately half were Gammaproteobacteria. Actinobacteria were the second most populous group (19%), followed by Firmicutes (13%) and Alphaproteobacteria (11%). Betaproteobacteria, Flavobacteria, and Acidobacteria were minor constituents. The taxonomic compositions of the isolates were variable according to the species of longicorn beetle. Particularly, an abundance of Actinobacteria existed in Moechotypa diphysis and Mesosa hirsute, which eat broadleaf trees; however, no Actinobacteria were isolated from Corymbia rubra and Monochamus alternatus, which are needle-leaf eaters. Considerable proportions of xylanase and pectinase producing bacteria in the guts of the longicorn beetles implied that the bacteria may play an important role in the digestion of woody diets. Actinobacteria and Gammaproteobacteria were the dominant xylanase producers in the guts of the beetles.

Isolation and characterization of a noval membrane-bound cytochrome C_553 from the strictly anaerobic phototroph, heliobacillus mobilis: Lee, Woo Yiel , Blankenship, Robert E. , Kim, Seung Ho; J. Microbiol. 1997;35(3):206-212.

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Abstract: Heliobacillus mobilis is a strictly anaerobic Gram-positive bacterium which contains a primitive Photosystem I-type reaction center. The membrane-bound cytochrome c_553 from the heliobacterium suggested to be the immediate electron donor to the photooxidized pigment (P798+) has been isolated and characterized. The heme protein was visualized as a major component with an apparent molecular size of 17kDa in TMBZ-staining analysis of the membrane preparation and showed characteristic α (552.5 nm), β (522nm), and Soret absorption (416 nm) peaks of a typical reduced c-type cytochrome in the partially purified sample. The internal 43 amino acid sequence of the electron donor was obtained by chemical agent and protease treatments followed by N-terminal sequencing of the resulting fragments. The internal sequence carries lots of lysine residues and a Cys-X-X-Cys-His sequence motif which are the characteristics of typical c-type cytochromes. The analysis of the sequence by FAST or FASTA program, however, did not show any significant similarity to other known heme proteins.

Morphological Diversity of Marine Microorganisms on Different Isolation Media: Shin Hye Park , Kae Kyoung Kwon , Deuk-Soo Lee , Hong Kum Lee; J. Microbiol. 2002;40(2):161-165.

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Abstract: Isolation frequency of microorganisms from marine sources was examined with different media and samples collected from the coastal area of Cheju Island. From sea water samples, about 1% of microorganisms from the total number of bacteria were recovered. Microorganisms were cultured at the much lower frequency of 10^-4 ?0^-6 from other marine sources, such as sediment, sponges and corals. The frequency of duplicated isolation was examined with 140 morphologically different colonies isolated on different media. Fourteen percent of them exhibited the same morphology on two different media. The duplication frequency of the isolates among three different media was 33%.

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