• Korean Journal of Microbiology
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• v.47 no.3
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• pp.268-274
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• 2011

Anabaena (Cyanobacteria, Nostocales) are important for water quality controls, because they are often responsible for freshwater green tides; moreover, some species are reported to produce hepatotoxin. In this study, we sequenced RNA polymerase beta subunit (rpoB) gene of Anabaena, and evaluated their sequences for the potential use of a molecular taxonomic marker in this taxon. Anabaena rpoB showed low DNA similarity and high genetic divergences when compared those of 16S rRNA, and the molecular differences were statistically significant (Student t-test, p<0.01). Parsimony analyses showed the rpoB gene evolves 4.8-fold faster than 16S rRNA. In addition, phylogeny of the rpoB gene separated each Anabaena strain more clearly compared with a 16S rRNA tree. These results suggest that the rpoB gene is a useful marker for the molecular phylogenetics and the species discrimination of Anabaena.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.78-86
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• 2006

We examined the genetic diversity in intra-populations of Korean shiner, Coreoleuciscus splendidus, in six major rivers (Bukhan, Namhan, Geum, Osipcheon, Nakdong and Seomjin river) of Korea based on two different mitochondrial genes, the mitochondrial cytochrome b and the 16S rRNA. Analysis of sequence variation in a 657-bp segment of the mitochondrial cytochrome b gene revealed deep divergence among populations (98.2~99.9%) and high genetic diversity from geographically isolated populations. Intra-specific variation in this 697-bp segment of the 16S rRNA gene sequences was very low and nearly identical. Six isolate populations of C. splendidus showed a high similarity (97.7%~99.7%). This result may be indicative of a complex history of connection and isolation of the rivers in the Korea peninsula.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1552-1559
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• 2011

Real time PCR was used in this study to determine the effect of triticale dried distillers grains with solubles (TDDGS) as a replacement for grain or barley silage in finishing diets on the presence of six classical ruminal bacterial species (Succinivibrio dextrinosolvens, Selenomonas ruminantium, Streptococcus bovis, Megasphaera elsdenii, Prevotella ruminicola and Fibrobacter succinogenes) within the rumen contents of feedlot cattle. This study was divided into a step-wise adaptation experiment (112 days) that examined the effects of adaptation to diets containing increasing levels of TDDGS up to 30% (n = 4), a short-term experiment comparing animals (n = 16) fed control, 20%, 25% or 30% TDDGS diets over 28 days, and a rapid transition experiment (56 days) where animals (n = 4) were rapidly switched from a diet containing 30% TDDGS to a barley-based diet with no TDDGS. It was found that feeding TDDGS as replacement for barley grain (control vs. 20% TDDGS) decreased 16S rRNA copy numbers of starch-fermenting S. ruminantium and S. bovis (p<0.001 and p = 0.04, respectively), but did not alter 16S rRNA copy numbers of the other rumen bacteria. Furthermore, feeding TDDGS as a replacement barley silage (20% vs. 25% and 30% TDDGS) increased 16S rRNA copy numbers of S. ruminantium, M. elsdenii and F. succinogenes (p<0.001; p = 0.03 and p<0.001, respectively), but decreased (p<0.001) the 16S rRNA copy number of P. ruminicola. Upon removal of 30% TDDGS and return to the control diet, 16S rRNA copy numbers of S. ruminantium, M. elsdenii and F. succinogenes decreased (p = 0.01; p = 0.03 and p = 0.01, respectively), but S. dextrinosolvens and S. bovis increased (p = 0.04 and p = 0.009, respectively). The results suggest that replacement of TDDGS for grain reduces 16S rRNA copy numbers of starch-fermenting bacteria, whereas substitution for barley silage increases 16S rRNA copy numbers of bacteria involved in fibre digestion and the metabolism of lactic acid. This outcome supports the contention that the fibre in TDDGS is highly fermentable.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.97-103
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• 2011

Two Gram positive bacterial strains, designated strain GC-1 and GC-4, were isolated from coastal seawater near Jeju Island in the Republic of Korea. The two strains were identified as members of the genus Bacillus, based on 16S rRNA gene sequencing and data for physiological characteristics analyses. A subtle difference in physiological and genotypical characteristics has led us to designate the strains GC-1 and GC-4. The strain GC-1 showed a 99.91% similarity in 16S rRNA gene sequencing with B. tequiliensis and B. subtilis subsp. inaquosorum and the strain GC-4 showed a 100% similarity in 16S rRNA gene sequencing with those of B. altitudinis, B. stratosphericus, and B. aerophilus. However, both strains exhibited different physiological and genotypical characteristics in many aspects from those of their phylogenetically closest neighbors listed above, which implies that genus Bacillus has diversified into various species during its evolutionary process.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.395-400
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• 2011

Phylogenetic analyses on the Phylum Mollusks has so far been conducted by many researchers in the world. However, there was no report on taxonomic analysis on Acila divaricata vigila which is belonging to Class Bivalvia, Subclass Protobranchia. In this study, we performed molecular phylogenetic analysis on Acila divaricata vigila using 16S rRNA sequence through maximum likelihood method. As a result, it is clearly divided into the legion of mollusk classification unit (when you zoom in order) and represented to support the current classification in the Phylum Mollusca belong to Class Bivalvia, Subclass Protobranchia, Subclass Pteriomorphia, Subclass Paleoheterodonta, Subclass Heterodonta and Subclass Anomalodesmacea. To our knowledge, this is the first report of molecular phylogenetic analysis on Acila divaricata vigila using 16S rRNA gene and these data suggests that 16S rRNA gene will be useful for analyzing the phylogenetic relationship of Subclass Protobranchia.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.347-351
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• 2007

Potato scab is prevalent in all potato-growing areas of Jeju Island and causes economically significant losses. Streptomyces species are known as pathogens of potato scab. In this study, we analyzed the 16S rRNA sequences of Streptomyces spp, which are isolated from potato scab lesions in Jeju Island, and constructed 16S rRNA phylogenetic tree. All isolates were clearly differentiated into the genus Streptomyces, and the tree also showed that new scab-causing Streptomyces spp or not yet named species of Streptomyces are existed in Jeju Island, Korea.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.506-511
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• 2004

Maintaining dissolved oxygen (DO) at sufficiently low concentration in the aeration tank at a wastewater treatment plant (WWTP) is essential for reduction of the costs of operation and maintenance. On the other hand, the low DO level may result in adverse effect on the integrity of the activated sludge, A typical and disastrous outcome frequently experienced is the outgrowth of filamentous microorganisms, which is called as filamentous bulking, In addition to the traditional methods such as sludge settleability and microscopic observation of the culture, molecular techniques including polymerase chain reaction (PCR) amplification followed by 16S rRNA sequencing were applied to identify filamentous bacteria present in bulking sludge under a condition of low DO concentration, Two morphologically distinct groups, presumably consisting of Sphaerofilus nafans, and Eikelboom Type 1701 or Type 1851, were identified through microscopic observation. They were further confirmed by subsequent 16S rRNA sequencing. Dominant filamentous bacteria identified by the molecular techniques were consisted of three major groups. Sequences of partial 16S rRNA cloned showed that the filamentous bulking organisms were closely related to Eikelboom Type 021N and Eikelboom Type 1701, and Sphaerotilus natans, respectively. Molecular methods were found to possess a strong potential of direct examination of the microbial community of an activated sludge system.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.398-406
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• 2015

Culture-dependent ARDRA and culture-independent DGGE were employed to investigate the bacterial community associated with the marine sponge Halichondria panicea collected from Jeju Island. A total of 120 bacterial strains associated with the sponge were cultivated using modified Zobell and Marine agar media. PCR amplicons of the 16S rRNA gene from the bacterial strains were digested with the restriction enzymes HaeIII and MspI, and then assigned into different groups according to their restriction patterns. The 16S rRNA gene sequences derived from ARDRA patterns showed more than 96% similarities compared with known bacterial species, and the isolates belonged to four classes, Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes, and Firmicutes, of which Alphaproteobacteria was dominant. DGGE fingerprinting of 16S rRNA genes amplified from the sponge-derived total gDNA showed 14 DGGE bands, and their sequences showed 100% similarities compared with the sequences available in GenBank. The sequences derived from DGGE bands revealed high similarity with the uncultured bacterial clones. DGGE revealed that bacterial community consisted of seven classes, including Alphaproteobacteria, Gammaproteobacteria, Acidobacteria, Actinobacteira, Bacteroidetes, Cyanobacteria, and Chloroflexi. According to both the ARDRA and DGGE methods, three classes, Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes, were commonly found in H. panicea. However, overall bacterial community in the sponge differed depending on the analysis methods. Sponge showed more various bacterial community structures in culture independent method than in culture-dependent method.

• Journal of Life Science
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• v.24 no.4
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• pp.361-369
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• 2014

Broad-range and specific 16S rRNA gene PCR is used for detection and identification of bacterial pathogens in clinical specimens from patients with a high suspicion for infection. We describe the development of a broad-range and specific PCR primer, based on bacterial 16S rRNA, for use in routine diagnostic clinical microbiology services. The primers were designed by using conservative regions of 16S rRNA sequences from 10 strains. Ninety-eight clinical strains were isolated from clinical patient specimens. A total of 98 strains of bacteria were identified by phenotypic methods; PCR with newly designed primers and universal primers. All purified PCR products were sequenced using both forward and reverse primers on an automated DNA analyzer. In this study, we evaluated the usefulness of the newly designed primers and the universal primers for the detection of bacteria, and both these techniques were compared with phenotypic methods for bacteria detection. When we also tested 98 strains of clinical isolates with newly designed primers, about 778 bp DNA fragments were amplified and identified from all strains. Of the 98 strains, 94 strains (95.9%) correspond in comparison with phenotypic methods. The newly designed primers showed that the identities of 98 (100%) strains were the same as those obtained by universal PCR primers. The overall agreement between the newly designed primers and universal primers was 100%. The primer set was designed for rapid, accurate, and cheap identification of bacterial pathogens. We think the newly designed primer set is useful for the identification of pathogenic bacteria.

• Journal of Korean society of Dental Hygiene
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• v.13 no.5
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• pp.889-900
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• 2013

Objectives : Molecular biology techniques were employed to assess diversity of bacterial in children's dental caries. Methods : DNA of germs was extracted and the diversity of the 16S rRNA clones was analyzed by amplified rDNA restriction analysis and sequencing. The experimental samples were pit and fissure caries (PC), deep dentinal caries (DC), smooth surface caries (SC), and supragingival plaque (PQ) from 50 children of age less than 12 years old. The control group was healthy teeth supragingival plaque (HT). Thirty clones from each 16S rRNA clone library of 5 samples were randomly selected, thus a total of 150 clones were analyzed. Results : Amplified rDNA restriction analysis uncovered 18, 20, 11, 17, and 22 phylotypes from healthy teeth, pit and fissure caries, deep dentinal caries, smooth surface caries, and supragingival plaque, respectively. Sequencing analysis found the dominance of Actinomycs naeslundii and Fusobacterium nucleatum in the healthy teeth; Leptotrichia sp. in the pit and fissure caries; Actinomyces sp., Streptococcus mutans, and Rahnella aquatilis in the deep dentinal caries; Streptococcus mutans and Actinomyces sp. in the smooth surface caries; Enterobacter hormaechei and Streptococcus sanguinis in the supragingival plaque. Conclusions : Clonal analysis identified 6 phyla, 20 genera, and 51 species.