• Korean Journal of Environmental Agriculture
• /
• v.39 no.1
• /
• pp.65-74
• /
• 2020

BACKGROUND: Soil carbon sequestration has been investigated for a long time because of its potential to mitigate the greenhouse effect. No- or reduced tillage, crop rotations, or cover crops have been investigated and practiced to sequester carbon in soils but the roles of soil biota, particularly microorganisms, have been mostly ignored although they affect the amount and stability of soil organic matters. METHODS AND RESULTS: In this study we analyzed the organic matter and microbial community in organically cultivated corn field soils where no-tillage (NT) or conventional tillage (CT) had been practiced for about three years. The amounts of organic matter and recalcitrant carbon pool were 18.3 g/kg dry soil and 4.1 g C/kg dry soil, respectively in NT soils, while they were 12.4 and 2.5, respectively in CT soils. The amounts of RNA and DNA, and the copy numbers of bacterial 16S rRNA genes and fungal ITS sequences were higher in NT soils than in CT soils. No-tillage treatment increased the diversities of soil bacterial and fungal communities and clearly shifted the bacterial and fungal community structures. In NT soils the relative abundances of bacterial phyla known as copiotrophs, Betaproteobacteria and Bacteroidetes, increased while those known as oligotrophs, Acidobacteria and Verrucomicrobia, decreased compared to CT soils. The relative abundance of a fungal phylum, Glomeromycota, whose members are known as arbuscular mycorrhizal fungi, was about two time higher in NT soils than in CT soils, suggesting that the higher amount of organic matter in NT soils is related to its abundance. CONCLUSION: This study shows that no-tillage treatment greatly affects soil microbial abundance and community structure, which may affect the amount and stability of soil organic matter.

• The Korean Journal of Mycology
• /
• v.50 no.4
• /
• pp.263-274
• /
• 2022

Lentinula edodes is an important commercial mushroom and there have been several reports of viral infections in L. edodes. Two mycoviruses (LeV-HKB and LeNSRV1) were detected in Sanbaekhyang (NIFoS 2778) and Taehyanggo (NIFoS 4317), the sawdust-cultivated commercial strains. The vertical transmission rates of the viruses were investigated by detecting the viruses in 80 monokaryotic strains derived from basidiospores isolated from the fruiting bodies of each strain. Most of the monokaryotic strains were infected with the virus and the two viruses showed different levels of meiotic stability, with LeV-HKB showing higher meiotic stability than LeNSRV1. Therefore, it seems that the vertical transmission mechanism of mycoviruses is different depending on the virus species. We also examined the mycelial growth rate of the monokaryotic strains and compared the growth rate according to virus infection status. Although there was no statistically significant correlation between viral infection and mycelial growth rate, we found that the average growth rate was reduced by additional virus infection. We expect our data to contribute to a greater understanding of the mechanism of the vertical transmission of mycoviruses, and promoting breeding using virus-free monokaryotic strains.

• Korean Journal of Microbiology
• /
• v.43 no.4
• /
• pp.325-330
• /
• 2007

RNase E is an essential Escherichia coli endoribonuclease that plays a major role in the decay and processing of a large fraction of RNAs in the cell and expression of N-terminal domain consisted of 1-498 amino acids (N-Rne) is sufficient to support normal cellular growth. By utilizing these properties of RNase E, we developed a genetic system to screen for amino acid substitutions in the catalytic domain of the protein (N-Rne) that lead to various phenotypes. Using this system, we identified three kinds of mutants. A mutant N-Rne containing amino acid substitution in the S1 domain (I6T) of the protein was not able to support survival of E. coli cells, and another mutant N-Rne with amino acid substitution at the position 488 (R488C) in the small domain enabled N-Rne to have an elevated ribonucleolytic activity, while amino acid substitution in the DNase I domain (N305D) only enabled N-Rne to support survival of E. roli cells when the mutant N-Rne was over-expressed. Analysis of copy number of ColEl-type plasmid revealed that effects of amino acid substitution on the ability of N-Rne to support cellular growth stemmed from their differential effects on the ribonucleolytic activity of N-Rne in the cell. These results imply that the genetic system developed in this study can be used to isolate mutant RNase E with various phenotypes, which would help to unveil a functional role of each subdomain of the protein in the regulation of RNA stability in E. coli.

• Parasites, Hosts and Diseases
• /
• v.54 no.1
• /
• pp.39-46
• /
• 2016

Theileria annulata is a tick-borne intracellular protozoan parasite that causes tropical theileriosis, a fatal bovine lymphoproliferative disease. The parasite predominantly invades bovine B lymphocytes and macrophages and induces host cell transformation by a mechanism that is not fully comprehended. Analysis of signaling pathways by quantitative real-time PCR (qPCR) could be a highly efficient means to understand this transformation mechanism. However, accurate analysis of qPCR data relies on selection of appropriate reference genes for normalization, yet few papers on T. annulata contain evidence of reference gene validation. We therefore used the geNorm and NormFinder programs to evaluate the stability of 5 candidate reference genes; 18S rRNA, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ACTB (${\beta}-actin$), PRKG1 (protein kinase cGMP-dependent, type I) and TATA box binding protein (TBP). The results showed that 18S rRNA was the reference gene most stably expressed in bovine PBMCs transformed and non-transformed with T. annulata, followed by GAPDH and TBP. While 18S rRNA and GAPDH were the best combination, these 2 genes were chosen as references to study signaling pathways involved in the transformation mechanism of T. annulata.

• Korean Journal of Microbiology
• /
• v.52 no.4
• /
• pp.487-494
• /
• 2016

In Saccharomyces cerevisiae, Paf1 complex consists of five proteins, and they are structurally and functionally well conserved in yeast, fruit fly, plants, and human. With binding to RNA polymerase II from transcription start site to termination site, Paf1 complex functions as a platform for recruiting many types of transcription factors to RNA polymerase II. Paf1 complex contributes to H2B ubiquitination and indirectly influences on H3K4 di- and tri-methylation by histone crosstalk. But the individual effects of five components in Paf1 complex on these two histone modifications including H2B ubiquitination and H3K4 methylation largely remained to be identified. In this study, we constructed the single-gene knockout mutants of each Paf1 complex component and observed H3K4 mono-, di-, and trimethylation as well as H2B ubiquitination in these mutants. Interestingly, in each ${\Delta}paf1$, ${\Delta}rtf1$, and ${\Delta}ctr9$ strain, we observed the dramatic defect in H3K4 monomethylation, which is independent of H2B ubiquitination, as well as H3K4 di- and trimethylation. However, the protein level of Set1, which is methyltransferase for H3K4, was not changed in these mutants. This suggests that Paf1 complex may directly influence on H3K4 methylation by directly regulating the activity of Set1 or the stability of Set1 complex in an H2B ubiquitination independent manner.

• Journal of Aquaculture
• /
• v.21 no.3
• /
• pp.190-195
• /
• 2008

We investigated the changes in growth, digestive enzymes activities, nucleic acids contents and RNA/DNA ratio of flounder Paralichthys olivaceus larvae (C for Paracyclopina nana, A for Artemia, and M for Mix of C and A) for 14 to 28 DAH. Body length of flounder larvae showed the best in the C trial at 28 DAH. The change of nucleic acids contents showed faster in C and M trials than A trial. And RNA/DNA ratio showed the significantly faster changes in C trial than A trial. High metamorphosis rates were also observed in C and M trial. $\alpha$-amylase activities increased gradually up to 28 DAH in all trials. Total alkaline protease (TAP) activities of A trial showed the highest value to 9 mU/larvae at 26 DAH. But others trials showed lower to $5{\sim}6$ mU/larva than A trial. TAP:$\alpha$-amylase activity ratio did not significantly changed to $0.025{\sim}0.053$ in A trial during the experiments. But, C and M trials tended to gradually decrease from $0.078{\sim}0.083$ (initial) to $0.013{\sim}0.018$ (final). Therefore, it shown the ratio gradually decreased of TAP:$\alpha$-amylase activity, stability of TAP activity, and rapid change of nucleic acids in trials grown positively. Thus, because P. nana could continuously supply the optimal nutrients for flounder larvae, we suggested the supplement of the copepod to an efficient feed of the flounder larvae.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.4
• /
• pp.759-766
• /
• 2008

Among more than a hundred colonies of fungi isolated from soil samples, DY-52 has been screened as an extracellular chitin deacetylase (CDA) producer. The isolate was further identified as Mortierella sp., based on the morphological properties and the nucleotide sequence of its 18S rRNA gene. The fungus exhibited maximal growth in yeast peptone glucose (YPD) liquid medium containing 2% of glucose at pH 5.0 and $28^{\circ}C$ with 150 rpm. The CDA activity of DY-52 was maximal (20 U/mg) on the 3rd day of culture in the same medium. The CDA was inducible by addition of glucose and chitin. The enzyme contained two isoforms of molecular mass 50 kDa and 59 kDa. This enzyme showed a maximal activity at pH 5.5 and $60^{\circ}C$. In addition, it had a pH stability range of 4.5-8.0 and a temperature stability range of $4-40^{\circ}C$. The enzyme was enhanced in the presence of $Co^{2+}$ and $Ca^{2+}$. Among various substrates tested, WSCT-50 (water-soluble chitin, degree of deacetylation 50%), glycol chitin, and crab chitosan (DD 71-88%) were deacetylated. Moreover, the CDA can handle N-acetylglucosamine oligomers $(GlcNAc)_{2-7}$.

• Biomedical Science Letters
• /
• v.18 no.2
• /
• pp.165-168
• /
• 2012

Hox proteins containing DNA-binding homedomain act as transcription factors important for anteroposterior body patterning during vertebrate embryogenesis. However, the precise mechanisms by which signal pathways are transduced to regulate the Hox gene expression are not clear. In the course of an attempt to isolate an upstream regulatory factor(s) controlling Hox genes, protein kinase B alpha (Akt1) has been identified as a putative regulator of Hox genes through in silico analysis (GEO profile). In the Gene Expression Omnibus (GEO) dataset GDS1784 at the NCBI (National Center for Biotechnology Information) site, Hox genes were differentially expressed depending on the presence or absence of Akt1. Since it was not well known how Akt1 regulates the specific Hox genes, whose transcription was reported to be regulated by epigenetic modifications such as histone acetylation, methylation etc., the expression of Gcn5, a histone acetyltransferase (HAT), was analyzed in wild type (WT) as well as in $Akt1^{-/-}$ mouse embryonic fibroblast (MEF) cells. RT-PCR analysis revealed that the amount of Gcn5 mRNA was similar in both WT and $Akt1^{-/-}$ MEFs. However, the protein level of Gcn5 was significantly increased in $Akt1^{-/-}$ MEF cells. The half life of Gcn5 was 1 hour in wild type whereas 8 hours in $Akt1^{-/-}$ MEF. These data all together, indicate that Gcn5 is post-transcriptionally down-regulated and the protein stability is negatively regulated by Akt1 in MEF cells.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.10
• /
• pp.1488-1494
• /
• 2020

Rho guanine nucleotide dissociation inhibitor 1 (RhoGDI1) plays important roles in numerous cellular processes, including cell motility, adhesion, and proliferation, by regulating the activity of Rho GTPases. Its expression is altered in various human cancers and is associated with malignant progression. Here, we show that RhoGDI1 interacts with Cullin 3 (CUL3), a scaffold protein for E3 ubiquitin ligase complexes. Ectopic expression of CUL3 increases the ubiquitination of RhoGDI1. Furthermore, potassium channel tetramerization domain containing 5 (KCTD5) also binds to RhoGDI1 and increases its interaction with CUL3. Ectopic expression of KCTD5 increases the ubiquitination of RhoGDI1, whereas its knockdown by RNA interference has the opposite effect. Depletion of KCTD5 or expression of dominant-negative CUL3 (DN-CUL3) enhances the stability of RhoGDI1. Our findings reveal a previously unknown mechanism for controlling RhoGDI1 degradation that involves a CUL3/KCTD5 ubiquitin ligase complex.

• Food Science of Animal Resources
• /
• v.39 no.5
• /
• pp.804-819
• /
• 2019

Ezine cheese is a non-starter and long-ripened cheese produced in the Mount of Ida region of Canakkale, Turkey, with a protected designation of origin status. Non-starter lactic acid bacteria (NSLAB) have a substantial effect on the quality and final sensorial characteristics of long-ripened cheeses. The dominance of NSLAB can be attributed to their high tolerance to the hostile environment in cheese during ripening relative to many other microbial groups and to its ability to inhibit undesired microorganisms. These qualities promote the microbiological stability of long-ripened cheeses. In this study, 144 samples were collected from three dairies during the ripening period of Ezine cheese. Physicochemical composition and NSLAB identification analyses were performed using both conventional and molecular methods. According to the results of a 16S rRNA gene sequence analysis, 13 different species belonging to seven genera were identified. Enterococcus faecium (38.42%) and E. faecalis (18.94%) were dominant species during the cheese manufacturing process, surviving 12 months of ripening together with Lactobacillus paracasei (13.68%) and Lb. plantarum (11.05%). The results indicate that NSLAB contributes to the microbiological stability of Ezine cheese over 12 months of ripening. The isolation of NSLAB with antimicrobial activity, potential bacteriocin producers, yielded defined collections of natural NSLAB isolates from Ezine cheese that can be used to generate specific starter cultures for the production of Ezine cheese (PDO).