Jong-Guk Kim

This experiment was conducted to investigate the characteristics of pollen-crossing between bensulfuron-methyl resistant and susceptible Monochoria korsakowii as a factor of dispersal mechanism. The F₁ seedlings progenies harvested from crossing susceptible biotype (S)× S died after treatment with bensulfuron-methyl. Although the other progenies harvested from crossing between S and resistant biotype (R), or between both resistant biotypes were survived at the same treatment. Most of F₂ progenies from back-crossing between the surviving S× R progenies and susceptible biotype survived at recommended dose of bensulfuron-methyl and did not satisfy χ².

The optimal conditions for production of Monascus sp. KM100l cell mass on submerged culture and production of monacolin K on rice solid culture were investigated. An overproducing mutant of Monascus pigments, KM 1001 mutant, from Monascus purpureus KCCM60016 was selected by NTG treatment. The optimal medium for the production of KM100l mutant cell mass is instructed to be composed of 3% glucose, 2% yeast extract, 0.1% KH₂PO₄, 0.05% MgSO₄ ㆍ 7H₂O, 0.2% L-asparagine, pH 4.5, and the optimal inoculum size and shaking speed were 1.5× 10∨ 6 spores/50 m1 medium and 150 rpm, respectively.

An improvement on allelopathic potential in crop varieties will have a great impact on weed management systems. Biotechnology is revolutionizing pesticide industry in countries that have accepted transgenic crops. A transgenic herbicide resistant crops mostly using glyphosate have not led to significant reduction in the amount of herbicide used. Glyphosate is a very safe herbicide but it is not low use-rate herbicide. An improvement on crop allelopathy by transgenic technology can be an alternative to reduce herbicide use-rate. For this purpose, the target chemical and gene should above all be identified.

Heat-shock treatment to Kouketsumochi known as a high allelopathic rice high cultivar and Lemont known as a low allelopathic cultivar increased allelopathic effects on barnyardgrass growth. Root exudates of Kouketsumochi and Lemont after heat-shock treatment inhibited 44.4% and 23.8% of shoot growth, 38.8% and 15.2% of root growth, 54.7% and 29.6% of dry weight of barnyardgrass, respectively. Several compounds such as tetradecanoic acid, n-hexadecanoic acid and octadecanoic acid were detected in both Kouketsumochi and Lemont with of without heat-shock treatment by GC/MS.

Keeping in view the traditional uses of medicinal plants, this study was conducted to evaluate the antifungal activity of selected members of family Rosaceae for the first time. Activity of Rosa indica L. Prunus amygdalus L. and Prunus armeniaca L was evaluated against the Penicillium digitatum L. Antifungal activity of the aforementioned plant extracts were indicated by the measuring zone of inhibition on agar plate. Highest activity against the test strain of fungus was recorded in ethanol extracts of the selected plants. Antifungal activity of extracts from the selected plants was dependent on the concentration of the extracts with highest activity being recorded when its strength was 15%. Maximum zone of inhibition (19.6 mm) was formed against the test fungus exposed to 15% root extract of R. indica L. taken in ethanol. However, aqueous root extract of the same plant was less effective indicating that the bioactive compound (s) in the root were of relatively low polarity. Bioactive compounds of the other two plants were also of low polarity as their activity was relatively greater when extracted in ethanol than that in aqueous extract. Contrary to R. indica, Leave of P. armeniaca were seat of high amount of bioactive compounds. While flavonoids and tannin were recorded in all samples, alkaloids and carbohydrates were found only in R. indica L. Similarly, fixed oil and fats were present in P. amygdalus L. and P. armeniaca L only. According to antifungal activity the aforementioned plants can be arranged as R. indica L.> P. armeniaca L.> P. amygdalus L. It may be concluded that these plants may be of great medicinal value and may provide a source of …

The diversity and plant growth-promoting ability of fungal endophytes that are associated with five halophytic plant species (Phragmites australis, Suaeda australis, Limonium tetragonum, Suaeda glauca Bunge, and Suaeda maritima) growing in the Buan salt marsh on the west coast of South Korea have been explored. About 188 fungal strains were isolated from these plant samples’ roots and were then studied with the use of the internal transcribed spacer (ITS) region (ITS1-5.8 S-ITS2). The endophytic fungal strains belonged to 33 genera. Alternaria (18%) and Fusarium (12.8%), of the classes Dothideomycetes and Sordariomycetes, were most rampant in the coastal salt marsh plants. There was a higher diversity in fungal endophytes that are isolated from S. glauca Bunge than in isolates from other coastal salt marsh plants. Plant growth-promoting experiments with the use of Waito-C rice seedlings show that …

In a study of the fungal diversity on Ulleung Island in Korea, three novel strains of Penicillium were isolated. Different sites on Ulleung Island were selected for collecting endophytic fungi, and three endophytic fungal strains showed unique morphological characteristics. DNA sequence of the internal transcribed spacer, β-tubulin, calmodulin, and RNA polymerase II second largest subunit regions of the strains were analyzed and they showed unique taxonomic position from the other species of Penicillium section Sclerotiora. The new strains were named Penicillium ulleungdoense sp. nov. As the novel endophytic Penicillium taxa were discovered in a unique environment, the data could be meaningful for understanding the geographical distribution of Ascomycetes on Ulleung Island.

Ficus carica L.,(Moraceae), commonly found in tropical and subtropical areas, known for its ethno-medicinal uses. The current work aimed to study macro and microscopic features and screen the plant ethanol extract for its antioxidant and antimicrobial potential. 1, 1-diphenyl-2-picryl hydrazyl (DPPH) was used for antioxidant and Agar-well-diffusion method for screening antimicrobial activity. The results revealed that powdered drug possess unicellular, uniserrate covering trichomes, parenchymatous tissue containing spiral vascular strands, anomocytic stomata and calcium oxalate crystals. Phytochemically, the extract possesses reducing sugars, polysaccharides, oxalic acid, amino acid and proteins. The antioxidant activity of Ficus carica leaves ethanol extract, using various concentration (125, 250, 500, 750 and 1000 µg/ml) gave the results of 21.42±01, 29.65±03, 53.15±03, 57.00±01 and 62.99±05, respectively. The leaves ethanol extract used for antibacterial activity have concentrations of 200 and 500 mg/ml, both of which were found effective against the selected bacterial strains. K. pneumonia was inhibited (18 & 28mm), E. coli was found (20 & 26 mm) susceptible, Staphylococcus aureus was inhibited with (24 and 26mm) and Pseudomonas aeruginosa was inhibited by (22 and 28mm). It is concluded from the present study that leaf ethanol extract of Ficus carica has good antioxidant constituents and possess positive antimicrobial chemical metabolites. These metabolites can be used to treat various infectious and chronic diseases caused by microbes. This work is important in order to assess the significance of Ficus carica used locally …

Photorhabdus spp. has a high molecular weight Tc toxin with insecticidal activity. These toxins have been suggested as an alternative to BT toxin from Bacillus thuringiensis. Herein, we constructed a cosmid library with the genome of M1021 and screened the Escherichia coli clones showing insect toxicity by injecting each clone into Galleria mellonella larvae. In a total of 1020 clones, one clone with high insecticidal activity was selected and the nucleotide sequence of the cosmid of the clone was determined. In cosmid PtC28, a gene with 87% homology to the tccB gene of Photorhabdus temperata was found. Consequently, we have isolated the tccB gene cassette from the M1021 and expressed in E. coli expression vectors. The toxin was produced in the form of inclusion bodies but the denatured and refolded recombinant TccB showed strong mortality to the G. mellonella larvae.

Titanium dioxide is an important material with massive applications in multiple fields. This review focus on the synthesis strategies utilized for pure TiO2 nanofibers (TONF) and the role of fiber formation on the activity for different applications. Many of the studied properties have been reported to have higher magnitudes. Some of the activities like fading capacity diminished upon fiber formation, while the others, adsorption, and catalytic properties enhanced. For most of the activities, TiO2 used as supporting materials and all such activities increased due to increased surface area in the case of TONF. For biological activities, catalytic properties like water splitting and pollutant degradation, TONF have been proved to better than the TiO2 bulk and nanoparticles. These activities are associated with a lesser band gap of TONF.

Since industrialization, the production and utilization of various chemicals has contributed to improving the quality of our lives, but the subsequent discharge of massive waste is inevitable, and environmental pollution is becoming more serious every day. Exposure to chemicals as a result of environmental pollution is having a negative effect on human health and the ecosystem, and cleaning up the polluted environment that can affect our lives is a very important issue. Toxic aromatic compounds have been detected frequently in soil, groundwater, and wastewater because of the extensive use of oil products, and phenol, which is used to produce synthetic resins, textiles, and dyes, is one of the major pollutants, along with insecticides and preservatives. Phenol can cause dyspnea, headache, vomiting, mutation, and carcinogenesis. Phenol-degrading bacterium DWB-1-8 was isolated from the activated sludge of textile wastewater; this strain was identified as Comamonas testosteroni by 16S rRNA gene sequencing. The optimal culture conditions for the cell growth and degradation of phenol were 0.7% K 2 HPO 4, 0.6% NaH 2 PO 4, 0.1% NH 4 NO 3, 0.015% MgSO 4· 7H 2 O, 0.001% FeSO 4· 7H 2 O, an initial pH of 7, and a temperature of 30℃. The strain was also able to grow by using other toxic compounds, such as benzene, toluene, or xylene (BTX), as the sole source of carbon.

The study established out to find the anti-fungal and anti-bacterial action of Ipomoea quamoclit. We focus on the study to find fractions, which are active against bacterial and fungal species. The fractions aqueous, chloroform, n-hexane, methanolic extract and ethyl acetate was obtained and were tested against the selected four fungal and four bacterial species which are very common in different hospitals of Khyber Pakhtunkhwa. The n-hexane fractions inhibit the growth of bacterial strains (46-48%) which was the highest inhibition zone and the lowest activity shown by crude methanolic extracts (38-44%) against all the selected bacterial strains. However, in ant-fungal activity, the highest activity shown by crude methanolic extracts (35-65%) against the four selected fungal species and lowest activity displayed by the aqueous fractions. The other fractions also shown some moderate activity but were significant.

In this work we report detailed investigations of structural, ac transport and magnetotransport properties of composites of reduced graphene oxide (rGO) and magnetite nanoparticles measured in the frequency range 10 Hz–2 MHz and in static magnetic fields upto 500 mT. AC conductivity of composite samples was enhanced by a factor of ~3 over that of the pure rGO even though the conductivity of magnetite is five orders of magnitude lower than that of rGO. We attribute this to charge transfer effects between the magnetite nanoparticles and the rGO matrix. Evidence of this is also observed in detailed Raman analysis of all samples. Further, we find a giant magnetoconductivity in the ac transport behavior of the composite samples. The rGO sample showed a negative magnetoconductivity of ~−15% at room temperature, while all composite samples showed positive magnetoconductivity with weak frequency …

Rhododendron mucronulatum, native to Korea, Mongolia, Russia and parts of northern China, is known not only for its medicinal properties but also as a tourist attraction. One of the most famous tourist destinations with R. mucronulatum is in Biseul Mountain County Park, Daegu, Korea. To investigate the relationship between R. mucronulatum and microbiome communities in the surrounding soil, three sites within the park were chosen for sampling in February and August. The soil samples were then passed through a pyrosequencing process for analysis of the bacterial communities, and a total of 404,899 sequencing reads were obtained. Between 2,349 and 4,736 operational taxonomic units (OTUs) were observed across the three sampling zones and two seasons; samples from the park entrance showed a higher number of OTUs than the other two sites, and samples from August had more OTUs than those from February. The sample from the second observation site displayed the fewest OTUs, particularly in February. According to Chao1 and Shannon indices, samples from the park entrance in August demonstrated the highest degree of species richness and diversity. Studying the bacterial communities across the six samples identified the common population as comprising 287 genera, 45 of which are only present in Biseul Mountain County Park and are expected to participate in the colonization of R. mucronulatum.

We investigated the physio-molecular effects of separate and combined cadmium (Cd; 200 μM) and salinity (NaCl; 100 mM) stress on date palm during silicon (Si; 1.0 mM) applications. The results showed that exogenous Si led to significant improvements in plant growth, as well as physiology when compared with non-Si-treated seedling under stressed (Cd/NaCl) conditions. Interestingly, Si application led to lower metal (Cd) uptake and enhanced plant macronutrient uptake under combined stress, in turn, alleviating the combined salinity- and Cd-induced oxidative stress by lowering the lipid peroxidation rate, and peroxidase and catalase activities. Furthermore, ascorbate peroxidase level and the cytosolic Cu/Zn superoxide dismutase expression were significantly enhanced by Si application under combined stress. We further analyzed the effect of Si on modulation of stress-related hormonal crosstalk. Si …

Tricholoma matsutake is an ectomycorrhizal fungus, related with the host of Pinus densiflora. Most of studies on T. matsutake have focused on mycelial growth, genes and genomics, phylogenetics, symbiosis, and immune activity of this strain. T. matsutake is known for its unique fragrance in Eastern Asia. The most major component of its scent is (R)-(-)-1-octen-3-ol and is biosynthesized from the substrate linoleic acid by the sequential reaction of lipoxygenase and peroxide lyase. Here, we report for the first time the biosynthesis of (R)-(-)-1-octen-3-ol of T. matsutake using the yeast Saccharomyces cerevisiae as a host. In this study, cDNA genes correlated with these reactions were cloned from T. matsutake, and expression studies of theses genes were carried out in the yeast Saccharomyces cerevisiae. The product of these genes expression study was carried out with Western blotting. The biosynthesis of (R)-(-)-1 …

Background In the soil ecosystem, microbial diversity exists and these diverse organisms interact with plant roots and influence the physicochemical properties of plants. Some of these diverse microorganisms can cause diseases or can provide beneficial interactions with plants. Rhizobacteria are well-known beneficial microorganism that colonize the plant root zone (rhizosphere) and are referred to as plant growth-promoting rhizobacteria (PGPR) that contribute to the promotion of plant growth either directly or indirectly. PGPRs are also known for their biocontrol abilities. Sclerotinia sclerotiorum, an Ascomycetous soil inhabiting fungus, causes white rot disease in cucumbers. This disease results in the loss of millions of dollars annually. The current study was conducted to isolate naturally occurring soil inhabiting bacteria that may promote plant growth under diseased conditions and also …

Screening for genes or markers relevant to bladder cancer (BC) tumorigenesis and progression is of vital clinical significance. The present study used reverse‑transcription quantitative PCR reaction assays to examine the expression of mRNA encoding Rho GTPase‑activating protein 9 (ARHGAP9) in BC tissue samples and to determine whether ARHGAP9 is an independent prognostic biomarker for non‑muscle invasive BC (NMIBC) and muscle invasive BC (MIBC). The results revealed that the downregulation of ARHGAP9 expression in the tissue of patients with NMIBC or MIBC was significantly associated with a poor prognosis. In patients with NMIBC, a high expression of ARHGAP9 was significantly associated with prolonged recurrence‑free survival, whereas in MIBC patients, it was significantly associated with an increased progression‑free and cancer‑specific survival. The risk of cancer‑specific death was 2 …

Genome sequencing of Tricholoma matsutake revealed its unusually large size as 189.0 Mbp, which is a consequence of extraordinarily high transposable element (TE) content. We identified that 702 genes were surrounded by TEs, and 83.2% of these genes were not transcribed at any developmental stage. This observation indicated that the insertion of TEs alters the transcription of the genes neighboring these TEs. Repeat-induced point mutation, such as C to T hypermutation with a bias over “CpG” dinucleotides, was also recognized in this genome, representing a typical defense mechanism against TEs during evolution. Many transcription factor genes were activated in both the primordia and fruiting body stages, which indicates that many regulatory processes are shared during the developmental stages. Small secreted protein genes (<300 aa) were dominantly transcribed in the hyphae, where symbiotic interactions occur with the hosts. Comparative analysis with 37 Agaricomycetes genomes revealed that IstB-like domains (PF01695) were conserved across taxonomically diverse mycorrhizal genomes, where the T. matsutake genome contained four copies of this domain. Three of the IstB-like genes were overexpressed in the hyphae. Similar to other ectomycorrhizal genomes, the CAZyme gene set was reduced in T. matsutake, including losses in the glycoside hydrolase genes. The T. matsutake genome sequence provides insight into the causes and consequences of genome size inflation.

산업화 이후 다양한 화학물질의 생산과 이용은 우리 삶의 질을 높이는데 기여하였지만 그로 인한 대량의 폐기물 방출은 필연적이며 환경오염은 날이 갈수록 심각해지고 있다. 환경오염에 의한 화학물질의 노출은 인간의 건강과 생태계에 악영향을 주고 있다. 우리의 삶에 영향을 줄 수 있는 오염된 환경을 정화하는 것은 매우 중요한 문제이다. 광범위한 석유화학제품의 사용으로 인해 독성 난분해성 방향족화합물이 토양, 지하수, 폐수 등에서 빈번하게 검출되고 있다. 특히 합성수지, 합성섬유, 염료, 살충제, 방부제 등의 원료로 사용되는 페놀은 주요 오염물질이며, 호흡곤란, 두통, 구토, 돌연변이, 발암 등을 일으킬 수 있다. 본 연구에서는 페놀분해균주인 DWB-1-8을 섬유폐수에서 분리, 동정하였으며 16S rRNA유전자 염기서열분석결과 Comamonas testosteroni로 동정 되었다. 본 실험 균주의 최적 생장 및 최적페놀분해 배양 조건은 0.7% K₂HPO₄, 0.6% NaH₂PO₄, 0.1% NH₄NO₃, 0.015% MgSO₄‧7H₂O, 0.001% FeSO₄‧7H₂O, 초기 pH 7 …