Journal of Microbiology

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

Microflora Profiling of Infected Root Canal before and after Treatment Using Culture-Independent Methods: Yasuhiro Ito , Takuichi Sato , Keiko Yamaki , Gen Mayanagi , Kazuhiro Hashimoto , Hidetoshi Shimauchi , Nobuhiro Takahashi; J. Microbiol. 2012;50(1):58-62. Published online February 27, 2012; DOI: https://doi.org/10.1007/s12275-012-0459-4

Abstract: This study aimed to profile the microflora in infected root canals before and after root canal treatment using cultureindependent
methods
. Six infected root canals in singlerooted teeth with periapical lesions from five subjects were included. Quantification of total bacteria was performed by real-time PCR with primers targeting 16S rRNA genes. PCR products with universal 16S rRNA gene primers were cloned and partially sequenced, and bacterial identification at the species level was performed by comparative analysis with the GenBank database. The concentration of extracted DNA before treatment was higher than that after root canal treatment, although the difference was not statistically significant. Sequence analysis revealed that oral bacteria such as Fusobacterium, Streptococcus, Olsenella, and Pseudoramibacter detected in cases before root canal treatment disappeared after treatment. These results suggest that the root canal microflora are distinct before and after root canal treatment, and that treatment changes the microflora in both quantity and quality.

Partial Purification of Factors for Differential Transcription of the rrnD Promoters for Ribosomal RNA Synthesis in Streptomyces coelicolor: Mi-Young Hahn , Jung-Hye Roe; J. Microbiol. 2007;45(6):534-540.; DOI: https://doi.org/2612 [pii]

Abstract: The Streptomyces coelicolor A3(2) genome contains six operons (rrnA to F) for ribosomal RNA synthesis. Transcription from rrnD occurs from four promoters (p1 to p4). We found that transcripts from the p1 and p3 promoters were most abundant in vivo in the early exponential phase. However, at later phases of exponential and stationary growth, transcripts from the p1 promoter decreased drastically, with the p3 and p4 transcripts constituting the major forms. Partially purified RNA polymerase supported transcription from the p3 and p4 promoters, whereas pure reconstituted RNA polymerase with core enzyme (E) and the major vegetative sigma factor sigmaHrdB (E.sigmaHrdB) did not. In order to assess any potential requirement for additional factor(s) that allow transcription from the p3 and p4 promoters, we fractionated a partially purified RNA polymerase preparation by denaturing gel filtration chromatography. We found that transcription from the p3 and p4 promoters required factor(s) of about 30-35 kDa in addition to RNAP holoenzyme (E.sigmaHrdB). Therefore, transcription from the p3 and p4 promoters, which contain a consensus -10 region but no -35 for sigmaHrdB recognition, are likely to be regulated by transcription factor(s) that modulate RNA polymerase holoenzyme activity in S. coelicolor.

Nucleotide Sequence and Secondary Structure of 5S rRNA from Sphingobium chungbukense DJ77: Hae-Ryong Kwon , Young-Chang Kim; J. Microbiol. 2007;45(1):79-82.; DOI: https://doi.org/2486 [pii]

Abstract: The 5S rRNA gene from Sphingobium chungbukense DJ77 was identified. The secondary structure of the 199-base-long RNA was proposed. The two-base-long D loop was the shortest among all of the known 5S rRNAs. The U19-U64 non-canonical pair in the helix II region was uniquely found in strain DJ77 among all of the sphingomonads.

Nosema sp. isolated from Cabbage White Butterfly (Pieris rapae) Collected in Korea: Ji Young Choi , Jong Gill Kim , Young Cheol Choi , Tae Won Goo , Jin Hee Chang , Yeon Ho J e , Keun Young Kim; J. Microbiol. 2002;40(3):199-204.

Abstract: A microsporidium, from cabbage white butterflies, Pieris rapae, collected in Korea, was purified and characterized according to its gene structure, spore morphology and pathogenicity. From the observation of the isolate by SEM and TEM, the endospores, exospores and nuclei, about 12 polar filament coils of the polar tube and posterior vacuoles were all identified. The nucleotide sequence was determined for a portion of genomic DNA which spans the V4 variable region of the small subunit rRNA gene. Comparison with the GenBank database for 15 other microsporidia species suggests that this isolate is most closely related to Nosema species. The pathogenicity against cabbage white butterflies was quantified by inoculating variable doses of spores to the second instar larvae. Peroral inoculation at a dosage of 10^8 spores/ml resulted in the death of all larvae prior to adult eclosion, but at lower spore dosages of 10^4 ?0^5 spores/ml, many adults successfully emerged. The median lethal dose (LD_50 ) was determined to be 4.6 X 10^6 spores/ml and the isolate also transmitted transovarially to the progeny eggs at a frequency of 92%.

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