Journal of Microbiology

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

Transcriptional Regulation of fksA, a β-1,3-Glucan Synthase Gene, by the APSES Protein StuA during Aspergillus nidulans Development: Bum-Chan Park , Yun-Hee Park , Soohyun Yi , Yu Kyung Choi , Eun-Hye Kang , Hee-Moon Park; J. Microbiol. 2014;52(11):940-947. Published online October 31, 2014; DOI: https://doi.org/10.1007/s12275-014-4517-y

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Abstract: The temporal and spatial regulation of β-1,3-glucan synthesis plays an important role in morphogenesis during fungal growth and development. Northern blot analysis showed that the transcription of fksA, the gene encoding β-1,3-glucan synthase in Aspergillus nidulans, was cell-cycle-dependent and increased steadily over the duration of the vegetative period, but its overall expression during the asexual and sexual stages was fairly constant up until the time of transcription cessation. In an A. nidulans strain mutated in the eukaryotic bHLH-like APSES transcription factor stuA1, the transcriptional level of fksA, and consequently the content of alkali-insoluble cell wall β-glucan, significantly increased at the conidial chain formation and maturation stage. Electrophoretic mobility shift assays revealed that StuA was bound to StREs (StuA Response Elements) on the fksA promoter region. Promoter analysis with sGFP-fusion constructs also indicated the negative regulation of fksA expression by StuA, especially during asexual development. Taken together, these data suggest that StuA plays an important role in cell wall biogenesis during the development of A. nidulans, by controlling the transcription level of fksA.

Review

Bovine Viral Diarrhea Virus Infection Induces Autophagy in MDBK Cells: Qiang Fu , Huijun Shi , Yan Ren , Fei Guo , Wei Ni , Jun Qiao , Pengyan Wang , Hui Zhang , Chuangfu Chen; J. Microbiol. 2014;52(7):619-625. Published online June 28, 2014; DOI: https://doi.org/10.1007/s12275-014-3479-4

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27 Citations

Abstract: Bovine viral diarrhea virus (BVDV) is an enveloped, positive-sense, single-stranded RNA virus that belongs to the genus Pestivirus (Flaviviridae). The signaling pathways and levels of signaling molecules are altered in Madin-Darby Bovine Kidney (MDBK) cells infected with BVDV. Autophagy is a conservative biological degradation pathway that mainly eliminates and degrades damaged or superfluous organelles and macromolecular complexes for intracellular recycling in eukaryotic cells. Autophagy can also be induced as an effective response to maintain cellular homeostasis in response to different stresses, such as nutrient or growth factor deprivation, hypoxia, reactive oxygen species exposure and pathogen infection. However, the effects of BVDV infection on autophagy inMDBK cells remain unclear. Therefore, we performed an analysis of autophagic activity after BVDV NADL infection using real-time PCR, electron microscopy, laser confocal microscopy, and Western blotting analysis. The results demonstrated that BVDV NADL infection increased autophagic activity and significantly elevated the expression levels of the autophagy-related genes Beclin1 and ATG14 inMDBK cells. However, the knockdown of Beclin1 and ATG14 by RNA interference (RNAi) did not affect BVDV NADL infection-related autophagic activity. These findings provided a novel perspective to elaborate the effects of viral infection on the host cells.

Validation Study

Generation of Expression Vectors for High-Throughput Functional Analysis of Target Genes in Schizosaccharomyces pombe: Jiwon Ahn , Chung-Hae Choi , Chang-Mo Kang , Chun-Ho Kim , Hee-Moon Park , Kyung-Bin Song , Kwang-Lae Hoe , Misun Won , Kyung-Sook Chung; J. Microbiol. 2009;47(6):789-795. Published online February 4, 2010; DOI: https://doi.org/10.1007/s12275-009-0010-4

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Abstract: An immediate challenge in the post-genomic era is to assign a biological functions to proteins unraveled by genome analysis. This report is based on studies conducted using Schizosaccharomyces pombe, a simple model organism, and presents various vector systems as tools for high-throughput functional analysis of human genes. We constructed S. pombe expression vectors for efficient cloning of genes via the Gateway system. We modified the pREP and pSLF series vectors, which are widely used for gene expression in S. pombe. The vectors constructed have a uniform backbone of S. pombe autonomously replicating sequence (ARS) elements with different selective markers, namely, ura4+ and Saccharomyces cerevisiae LEU2 complementing leu1. These vectors contain 3 different strengths of the inducible promoter nmt1, which affect the expression levels of the cloned open reading frames (ORFs). Further, target proteins can be fused with an N-terminal or C-terminal tag such as triple hemagglutinin (3× HA), enhanced green fluorescent protein (EGFP), or Discosoma red fluorescent protein (DsRed). We tested the feasibility of the constructed vectors by using 3 human genes, namely, RAB18, SCC-112, and PTEN. Proper expression of tagged RAB18 was confirmed by western blot analysis. Further, localization of RAB18, SCC112, and PTEN was demonstrated. The constructed vectors can be utilized for high-throughput functional analysis of heterologous genes.

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

Expression of a Recombinant Cry1Ac Crystal Protein Fused with a Green Fluorescent Protein in Bacillus thuringiensis subsp. kurstaki Cry-B: Jong Yul Roh , In Hee Lee , Ming Shun Li , Jin Hee Chang , Jae Young Choi , Kyung Saeng Boo , Yeon Ho Je; J. Microbiol. 2004;42(4):340-345.; DOI: https://doi.org/2101 [pii]

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Abstract: To investigate the co-expression and crystallization of a fusion gene between the Bacillus thuringiensis crystal protein and a foreign protein in B. thuringiensis, the expression of the Cry1Ac fused with green fluorescent protein (GFP) genes in a B. thuringiensis Cry-B strain was examined. The cry1Ac gene was cloned in the B. thuringiensis-E. coli shuttle vector, pHT3101, under the control of the native cry1Ac gene promoter, while the GFP gene was inserted into the XhoI site upstream of the proteolytic cleavage site, in the middle region of the cry1Ac gene (pProAc-GFP). The B. thuringiensis Cry-B strain carrying pProAc-GFP (ProAc-GFP/CB) did not produce any inclusion bodies. However, the transformed strain expressed fusion protein forms although the expression level was relatively low. Furthermore, an immunoblot analysis using GFP and Cry1Ac antibodies showed that the fusion protein was not a single species, but rather multiple forms. In addition, the N-terminal fragment of Cry1Ac and a non-fused GFP were also found in the B. thuringiensis Cry-B strain after autolysis. The sporulated cells before autolysis and the spore-crystal mixture after autolysis of ProAc-GFP/CB exhibited insecticidal activities against Plutella xylostella larvae. Accordingly, the current results suggest that a fusion crystal protein produced by the transfomant, ProAc-GFP/CB, can be functionally expressed but easily degraded in B. thuringiensis.

Green Fluorescent Protein as a Marker for Monitoring a Pentachlorophenol Degrader Sphingomonas chlorophenolica ATCC39723: Eun-Taex Oh , Jae-Seong So , Byung-Hyuk Kim , Jong-Sul Kim , Sung-Cheol Koh; J. Microbiol. 2004;42(3):243-247.; DOI: https://doi.org/2081 [pii]

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Abstract: Sphingomonas chlorophenolica ATCC39723 was successfully labeled with the gfp (green fluorescent protein) gene inserted into the pcpB gene by homologous recombination. As the gfp recombinant was easily distinguished from other indigenous organisms, the population of gfp recombinant was monitored after being released into the soil microcosms. Their population density dropped from 108 to 106 (cfu/ml) in the non-sterilized soil microcosms during the first 6 days. Moreover, the gfp recombinant was not detected even at lower dilution rates after a certain time period. The recombinant, however, survived for at least 28 days in the sterilized soil microcosms. Although the gfp recombinant did not degrade pentachlorophenol (PCP), this experiment showed the possibility of using gfp as a monitoring reporter system for S. chlorophenolica ATCC39723 and potentially other species of Sphingomonas.

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