NRPS (non-ribosomal pepetide synthetase) plays an important role in the biosynthesis of secondary metabolites, which includes economically important compounds such as antibiotics, antitumor agents, immune-suppressants, siderophores, toxins, etc. In most cases, however, their functions and biosynthesizing pathways have been still remained riddles because of their cryptic expression and recalcitrant genetics. In our previous genome analyses of Cordyceps bassiana C101, we predicted the sequences of secondary metabolite biosynthesizing gene clusters, which contain non-ribosomal pepetide synthetases whose functions are already known such as beauvericin, bassianolide, bassiatin, tenellin, beauverolides, and oosporein. The authors focused on nrps6 that has not been functionally studied. The single-gene deletion and overexpression mutants were established via Agrobacterium-mediated transformations. PCR, quantitative real-time PCR, and southern blot analyses were carried out to confirm the correct single-gene integrated homologous recombination. In further study, comparative metabolic profiling between wild-type and mutant strains will be followed by their detailed chemical structure analysis through NMR spectroscopy.
Sanghuangporus sanghuang (Hymenochaetaceae, Agaricomycetes) is a medicinal mushroom which has gained particular attention in Korea as a natural immune booster and a cancer suppressor. Recent molecular phylogenetic studies clarified the species concept of S. sanghuang extensively used in Asia including Korea, China, and Japan. In this study, we assembled its mitochondrial genome and identified the locations and functions of genes and coding regions using next-generation sequencing. Raw sequencing data was produced using PacBio approach, and assembled through hierarchical genome assembly process (HGAP). Determining the mitocondrial regions GeSeq and Artemis annotation tools were used. And the resulting gene map was visualized using OGDraw software. A total of 108 reads was aligned with a coverage of 11.87X. The entire mitochondrial genome was 111,734 bp in length, in which 24 proteins and 46 transfer RNAs were recognized. The overall base composition is 38.37% A, 38.42% T, 11.05% C and 12.14% G with an GC content of 23.2%. This mitochondrial genome data can be used to understand its phylogenetic relationship and taxonomic resolution and as a source of markers for population and species delimitation.
Isaria farinosa (Hypocreales, Ascomycota) is a cosmopolitan entomopathogenic fungus affecting a wide range of arthropod hosts. It has mainly been studied as a insecticidal agent to control the agricultural pests. To investigate the useful secondary metabolite(SM) genes in Isaria farinosa C1012 strain, de novo assembly and genome mining were carried out. A whole genome sequencing with PacBio RSII system generated NGS reads greater than 4Gb, which were assembled into 16 contigs using FALCON program. The total size of genome was 33.36Mb. The N50 and N90 were 6,686,213 and 1,912,865bp, respectively. The assembled genome data was analyzed with antiSMASH3 program with a default setting to localize the gene region responsible for synthesizing SMs, such as non-ribosomal peptide synthetases (NRPS) and polyketide synthase (PKS). In this study, we predicted 16 NRPS, 13 PKS, and 9 PKS-NRPS hybrid gene clusters in I. farinosa genome.
습식분쇄의 최적조건을 얻고자 부형제 종류, 농도, 습식분쇄시 rotor speed, bead size, feed rate, 분쇄회수를 달리하여 분쇄한 결과, 부형제로는 gum arabic을 사용하여 5%의 농도로 첨가할 때 가장 좋은 분쇄효과를 나타내었다. Rotor speed를 달리하여 습식분쇄한 결과, rotor speed가 증가할수록 좋은 결과를 나타내어 4,000 rpm에서 가장 우수한 것으로 나타났다. 원료와 직접 부딪혀 분쇄를 하게 되는 bead는 0.4 mm의 크기를 사용하였을 때 가장 작은 사이즈로 분쇄되는 것으로 나타났다. 분쇄가 이루어지는 chamber내에 원료를 공급하는 비율에 따른 결과에서는 40 L/h 의 속도로 공급했을 때 가장 작은 입도분포를 보였다. 분쇄회수에 따른 영향은 횟수에 따라서는 8회 이상으로 분쇄하였을때 0.6 μm이하의 입도분포가 90% 이상으로 나타나 10회를 분쇄하였을때 가장 좋은 효과를 나타내었다. 연속운전과 비연속운전의 비교에서는 연속운전이 더 효율적이었으며 부형제 종류에 따른 영향은 gum arabic을 첨가하여 분쇄하였을때 가장 우수한 결과를 나타내었다. 따라서 적절한 농도와 종류의 부형제 사용과 rotor speed, bead size, feed rate, 용매와의 혼합비의 최적공정을 수립한 습식분쇄기술로 초미세액상칼슘의 제조가 가능하였고, 습식분쇄기술을 식품가공기술로 활용할 수 있는 가능성을 확보하였다.