• Animal Bioscience
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• 제34권3_spc호
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• pp.371-384
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• 2021

Objective: Wheat bran (WB) was co-fermented with Aspergillus oryzae and phytase (Phy) to determine whether co-fermentation improve WB phosphorus and fiber utilization in Isa-brown layers. Methods: A total of 112 Isa brown layer were randomly divided into 7 treatments with 8 replicates per a treatment and 2 hens per a replicate. The treatments included basal diet (control), basal diet supplemented with 250 unit/kg Phy (control+Phy), diet with 10% WB (10% WB), diet with 5% WB and 250 unit/kg Phy (5% WB+Phy) diet with 10% WB and 250 unit/kg Phy (10% WB+Phy), diet with 5% fermented WB supplemented with molasses and phy (PCFWH) and 125 unit/kg Phy (5% PCFWH), and diet with 10% PCFWH (10% PCFWH). The intestinal microbial population, intestinal morphology, serum antioxidant enzyme activities, and excreta phosphorus content were assessed. Results: In PCFWH, spore counts, protease activity, xylanase activity, and ferulic acid were 8.50 log/g dry matter (DM), 190 unit/g DM, 120 unit/g DM, and 127 ㎍/g, respectively. Xylobiose and xylotriose were released in PCFWH, while they were not detectable in WB. Antioxidant capacity was also enhanced in PCFWH compared to WB. The 10% WB+Phy and 10% PCFWH groups produced higher egg mass, but hens fed 5% WB+Phy had the lowest amount of feed intake. Eggs from 10% PCFWH had better eggshell weight, eggshell strength, and eggshell thickness. Birds fed with 10% PCFWH also had higher serum superoxide dismutase and catalase activities. Compare to control, 10% PCFWH significantly reduced excreta phosphorus content. Conclusion: Diet inclusion of 10% PCFWH improved egg quality, antioxidant status, and excreta phosphorus content of laying hens.

• 식물분류학회지
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• 제39권1호
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• pp.12-23
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• 2009

거미꼬리고사리의 잡종성을 분석하기 위하여 모종으로 추정되는 꼬리고사리, 거미고사리와 함께 외부형태, 포자형태, 해부학적 형질 그리고 염색체에 관한 연구를 수행하였다. 거미꼬리고사리는 엽신이 선상 피침형으로 1회 우상분열을 하지만, 우편 기부가 중축에 넓게 붙어 거의 단엽에 가까운 형태를 띠어 거미고사리와 유사하거나 또는 도피침형이며 기부의 우편이 삼각상 피침형으로 2-3갈래져서 꼬리고사리와 유사한 특징을 동시에 가지고 있었다. 3 분류군의 포자의 표면무늬는 돌출된 날개를 형성하는 주름이 있고, 이들이 불규칙하거나 완전치 않은 망상을 형성하였다. 망상무늬의 분포양상은 꼬리고사리의 경우, 성긴 것부터 중간형까지, 거미고사리의 경우, 조밀한 것부터 중간형까지 나타난 반면, 거미꼬리고사리는 성긴 것부터 중간형 및 조밀한 것까지 모두 나타났다. 포자의 크기는 거미꼬리고사리가 평균 $54.63{\mu}m$로 $47.81{\mu}m$의 크기를 갖는 꼬리고사리와 $44.22{\mu}m$의 크기를 갖는 거미고사리보다는 큰 것으로 나타났다. 모든 분류군에서 잎의 표면세포는 파상형으로 나타났으나 꼬리고사리의 굴곡이 가장 얕았고, 거미고사리가 가장 깊었으며 거미꼬리고사리는 중간형으로 차이를 보였다. 또한 단위면적당($mm^2$) 기공의 수는 꼬리고사리가 67.00개로 가장 많았고, 거미고사리가 37.86개로 가장 적었으며, 거미꼬리고사리는 이들의 거의 중간인 45.91개로 나타나 차이를 보였다. 염색체의 수는 꼬리고사리와 거미고사리에서 2n = 72개로 나타난 반면, 거미꼬리고사리의 경우 마이산(전북)과 두륜산(전남)에서 채집된 개체에서 2n = 72개인 2배체와 불암산(서울)의 개체에서 2n = 144개인 4배체가 나타났다. 결과적으로 거미꼬리고사리는 잎의 형질, 포자의 표면무늬 및 크기, 잎의 표면세포의 형태와 기공 수 및 염색체의 변이등을 고려하였을 때 꼬리고사리와 거미고사리의 타가배수화과정을 거쳐 기원된 잡종으로 확인되었다.

• Mycobiology
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• 제39권4호
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• pp.317-320
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• 2011

Honey production from approximately 1.6 million colonies owned by about 199,000 Korean beekeepers was almost 23,000 metric tons in 2009. Nosema causes significant losses in honey production and the virus decreases population size. We initiated a survey of honey bee colonies on the blooming period of Acacia to determine the prevalence of Nosema and virus in 2011. Most Korean beekeepers have moved from the south to north of Korea to get Acacia nectar for 2 mon. This provided a valuable opportunity to sample bees originating from diverse areas in one location. Twenty hives owned by 18 beekeepers were sampled in this year. Nosema spore counts ranged from zero to 1,710,000 spores per bee. The average number of nosema spores per bee was 580,000. Approximately 95% of the colonies were infected with Nosema, based on the presence of spores in the flowering period of Acacia. This indicates that Nosema is the predominant species affecting honeybee colonies. Also, the seven most important honeybee viruses were investigated by reverse transcription-PCR. Among them, four different viruses were detected in samples. Black queen cell virus was present in all samples. Chronic bee paralysis virus was detected in 10% of samples. Deformed wing virus was present in only 5% of the samples. Prevalence of Sacbrood virus was 15%. However, Cloudy wing virus, Israel acute paralysis virus and kashmir bee virus were not detected in any of samples.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.11-11
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• 2014

Fungal pathogens have huge impact on health and economic wellbeing of human by causing life-threatening mycoses in immune-compromised patients or by destroying crop plants. A key determinant of fungal pathogenesis is their ability to undergo developmental change in response to host or environmental factors. Genetic pathways that regulate such morphological transitions and adaptation are therefore extensively studied during the last few decades. Given that epigenetic as well as genetic components play pivotal roles in development of plants and mammals, contribution of microbial epigenetic counterparts to this morphogenetic process is intriguing yet nearly unappreciated question to date. To bridge this gap in our knowledge, we set out to investigate histone modifications among epigenetic mechanisms that possibly regulate fungal adaptation and processes involved in pathogenesis of a model plant pathogenic fungus, Magnaporthe oryzae. M. oryzae is a causal agent of rice blast disease, which destroys 10 to 30% of the rice crop annually. Since the rice is the staple food for more than half of human population, the disease is a major threat to global food security. In addition to the socioeconomic impact of the disease it causes, the fungus is genetically tractable and can undergo well-defined morphological transitions including asexual spore production and appressorium (a specialized infection structure) formation in vitro, making it a model to study fungal development and pathogenicity. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Histone modifying enzymes were identified applying a search pipeline built upon profile hidden Markov model (HMM) to proteomes. The database incorporates 22,169 histone-modifying enzymes identified from 342 species including 214 fungal, 33 plants, and 77 metazoan species. The dbHiMo provides users with web-based personalized data browsing and analysis tools, supporting comparative and evolutionary genomics. Based on the database entries, functional analysis of genes encoding histone acetyltransferases and histone demethylases is under way. Here I provide examples of such analyses that show how histone acetylation and methylation is implicated in regulating important aspects of fungal pathogenesis. Current analysis of histone modifying enzymes will be followed by ChIP-Seq and RNA-seq experiments to pinpoint the genes that are controlled by particular histone modifications. We anticipate that our work will provide not only the significant advances in our understanding of epigenetic mechanisms operating in microbial eukaryotes but also basis to expand our perspective on regulation of development in fungal pathogens.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.15-15
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• 2014

Fusarium graminearum (teleomorph Gibberella zeae) is an important plant pathogen that causes head blight of major cereal crops such as wheat, barley, and rice, as well as causing ear and stalk rot on maize worldwide. Plant diseases caused by this fungus lead to severe yield losses and accumulation of harmful mycotoxins in infected cereals [1]. Fungi utilize spore production as a mean to rapidly avoid unfavorable environmental conditions and to amplify their population. Spores are produced sexually and asexually and their production is precisely controlled. Upstream developmental activators consist of fluffy genes have been known to orchestrate early induction of condiogenesis in a model filamentous fungus Aspergillus nidulans. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we characterized functions of the F. graminearum fluffy gene homologs [2]. We found that FlbD is conserved regulatory function for conidiogenesis in both A. nidulans and F. graminearum among five fluffy gene homologs. flbD deletion abolished conidia and perithecia production, suggesting that FlbD have global roles in hyphal differentiation processes in F. graminearum. We further identified and functionally characterized the ortholog of AbaA, which is involved in differentiation from vegetative hyphae to conidia and known to be absent in F. graminearum [3]. Deletion of abaA did not affect vegetative growth, sexual development, or virulence, but conidium production was completely abolished and thin hyphae grew from abnormally shaped phialides in abaA deletion mutants. Overexpression of abaA resulted in pleiotropic defects such as impaired sexual and asexual development, retarded conidium germination, and reduced trichothecene production. AbaA localized to the nuclei of phialides and terminal cells of mature conidia. Successful interspecies complementation using A. nidulans AbaA and the conserved AbaA-WetA pathway demonstrated that the molecular mechanisms responsible for AbaA activity are conserved in F. graminearum as they are in A. nidulans. F. graminearum ortholog of Aspergillus nidulans wetA has been shown to be involved in conidiogenesis and conidium maturation [4]. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidia dormancy by suppressing microcycle conidiation in F. graminearum. In A. nidulans, FlbB physically interacts with FlbD and FlbE, and the resulting FlbB/FlbE and FlbB/FlbD complexes induce the expression of flbD and brlA, respectively. BrlA is an activator of the AbaA-WetA pathway. AbaA and WetA are required for phialide formation and conidia maturation, respectively [5]. In F. graminearum, the AbaA-WetA pathway is similar to that of A. nidulans, except a brlA ortholog does not exist. Amongst the fluffy genes, only fgflbD has a conserved role for regulation of the AbaA-WetA pathway.

• 농약과학회지
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• 제18권3호
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• pp.161-167
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• 2014

Strobilurin계 살균제인 azoxystrobin에 대한 잿빛곰팡이병균 Botrytis cinerea의 저항성 발현 여부를 조사하였다. B. cinerea 균주는 $1.0{\mu}g\;mL^{-1}$의 azoxystrobin에 대한 반응을 기준으로 실험 균주 중에서 46.5%가 감수성 균주로, 53.5%가 저항성 균주로 판명되었다. 병원균을 분리한 지역별로 저항성 균주의 출현 비율은 경기, 경남, 부산에서 28.6, 41.9, 36.8%이었으며, 충남에서 81.1%로 다른 지역보다 높게 나타났다. 기주별로 저항성 균주는 딸기, 오이, 토마토에서 분리한 균주에서는 각각 68.0, 40.0, 50.0%, 고추에서는 9.1%만이 나타났다. Azoxystrobin에 대해서 감수성이었던 B. cinerea 11-20은 kresoxim-methyl과 trifloxystrobin에 대해서도 감수성 반응을 보였으며, 저항성 균주인 11-74는 3종의 살균제 모두에 대해서 교차 저항성이 있음을 보여 주었다. 본 실험의 결과 실험에 사용한 B. cinerea 균주의 53.5%가 저항성 반응을 보일 정도로 높은 저항성 출현율을 보였으며, 동일 계열의 살균제에 대한 교차 저항성 반응을 보이고 있기 때문에, 포장에서 strobilurin계 살균제에 대한 철저한 관리가 요구되어진다.

• 농약과학회지
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• 제14권2호
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• pp.148-156
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• 2010

마늘 저장병을 일으키는 푸른곰팡이병의 생물적 방제를 위하여 마늘 근면으로부터 부패억제효과가 우수한 Pantoea agglomerans S59-4(Pa59-4)를 선발하였다. 길항균 Pa59-4의 푸른곰팡이병에 대한 적정처리농도는 $10^7\sim10^8$ cfu/$m\ell$이었으며, Pa59-4의 처리효과는 병원균의 접종농도가 증가됨에 따라 감소되었다. 길항균 Pa59-4의 현탁액에 마늘을 침지 처리할 경우 저장 중 부패를 90%억제하였으며, 종구 분의 처리하여 파종하였을 때에도 무처리구 부패율이 86.7%인데 비해 Pa59-4 처리시 부패율이 23.1%로 부패를 현저히 감소시켰다. 마늘처리부위에서의 길항균의 밀도변동을 알아보기 위하여 항생제 마커로서 pimaricin과 vancomycin을 선발하였고 이들 항생제가 포함된 배지상에서 길항균 Pa59-4의 밀도변동을 저온조건과 상온조건으로 나누어 조사하였을 때 상처를 낸 마늘표면에서는 처리 후 30일까지도 밀도가 계속하여 증가하였으며, 저온 조건하에서는 처리 후 15일까지 증가하다가 그 이후에는 감소되는 것으로 나타났다. 길항균 Pa59-4의 산업화를 위하여 증량 제로 white carbon을 첨가하여 만든 미생물제제를 처리할 경우 저장 중 마늘부패를 40~50% 줄일 수 있었다. 이상의 결과로써 길항균 Pa59-4는 마늘저장 중 부패를 줄일 수 있는 유망한 길항균으로 판단되었다.