Paraconiothyrium Brasiliense Research Articles

Characterization and Pathogenicity of Fungal Species Associated with Dieback of Apple Trees in Northern Italy.

Severe dieback symptoms were recently observed on apple (Malus × domestica) trees in Northern Italy, representing a growing concern for producers. Surveys were conducted over a 3-year period (2019 to 2021), and five apple orchards, from 5 to 12 years old, were monitored. A total of 33 fungal isolates isolated from symptomatic plants was selected for characterization. The species identification was achieved through multilocus phylogenetic analyses performed on sequences of three genomic loci (ITS, tub2, and tef1). Morphological features were assessed, and the average growth rate at different temperatures was determined. Seven species were identified in association with dieback of apple trees: Botryosphaeria dothidea, Cadophora luteo-olivacea, Diaporthe rudis, Diplodia seriata, Eutypa lata, Kalmusia longispora, and Paraconiothyrium brasiliense. All the species were pathogenic when inoculated on healthy apple plants. B. dothidea resulted in the most aggressive infections. This study provides an insight into the fungal species diversity associated with apple dieback and provides basis for further investigations to assess the phytosanitary status of plant materials to recommend and implement effective management strategies.

Shedding light on Paraconiothyrium brasiliense: Secondary metabolites, biological activities, and computational studies

Fungi are renowned as a prolific source for the biosynthesis of therapeutically valuable metabolites. Paraconiothyrium genus (Leptosphaeriaceae) demonstrates remarkable potential for the biosynthesis of a wide array of metabolites, including macrolides, terpenoids, polyketides, phenolics, and furanones, which exhibit diverse bioactivities. The present review focused on the reported metabolites derived from Paraconiothyrium brasiliense, including their chemical structures and bioactive properties. Furthermore, it delves into the elucidation of the biosynthetic pathways for these metabolites. This review encompasses the description of over 92 compounds reported in the literature from 2010 to October 2023. In addition, in silico studies may explain the potential mechanisms underlying the neuroprotective properties of certain furanone derivatives against central nervous system disorders. Among the tested compounds against KEAP1 through Keap1/Nrf2 pathway-mediated neuroprotection, paraconfuranone I (48), paraconfuranone (50), and paraconfuranone L (51) displayed docking scores ranging from −6.158 to −6.612 kcal/mol, similar to the exciting reference compound which achieved the highest docking score of −6.633 kcal/mol. Moreover, new potential activities of some compounds as inhibitors against the LasR target of Pseudomonas aeruginosa were elucidated using molecular docking and absorption, distribution, metabolism, excretion, and toxicity prediction. Specifically, 1-(1’,2’-dideoxy-α-D-nucleopyranosyl)-β-carboline (73) had the highest docking score at −11.327 kcal/mol, followed by 1-acetyl-β-carboline (75) at −10.055 kcal/mol, in comparison to reference compound (docking score −10.023 kcal/ mol). In addition, ten other compounds displayed competitive docking scores ranging from −9.813 to −9.312 kcal/ mol. This suggested the potential of P. brasiliense as a promising lead for antibacterial and neuroprotective agents.

Synthesis and absolute configuration of paraconiothin I, a structurally unique sesquiterpene isolated from the endophytic fungus Paraconiothyrium brasiliense ECN258

The total synthesis and determination of the absolute configuration are described for paraconiothin I, an inhibitor against the nuclear receptor liver X receptor α, which is produced by the endophytic fungus Paraconiothyrium brasiliense ECN258. Our method for synthesizing paraconiothin I involved Evans asymmetric alkylation and Sharpless asymmetric dihydroxylation, which enabled us to develop an efficient synthetic approach for constructing the side-chain moiety of paraconiothin I. Through model synthesis, we discovered that the previously proposed relative configuration of the natural product was incorrect and determined the correct absolute configuration of the natural product by comparing the specific rotations of the synthetic and natural products.

Grapevine dieback caused by Botryosphaeriaceae species, Paraconiothyrium brasiliense, Seimatosporium vitis-viniferae and Truncatella angustata in Piedmont: characterization and pathogenicity

Grapevine Trunk Diseases (GTDs) are major threats in Mediterranean countries, causing economic losses due to reduced grape yields and long-term vine productivity, as well as death of grapevines. A survey was conducted in Piedmont (Northern Italy) during 2021-2022 to investigate the species diversity and distribution of GTD pathogens in this important Italian wine region. Morphological and multi-locus phylogenetic analyses (based on ITS, tef1, tub2, act and rpb2) identified species of Botryosphaeriaceae at high frequency, including Botryosphaeria dothidea, Diplodia mutila, Diplodia seriata and Neofusicoccum parvum. Other pathogens commonly associated with GTDs, including Eutypa lata, Fomitiporia mediterranea and Phaeomoniella chlamydospora, were also isolated. Less commonly isolated species included Neocucurbitaria juglandicola, Paraconiothyrium brasiliense, Seimatosporium vitis-viniferae and Truncatella angustata. Pathogenicity tests with two representative isolates of each species were carried out using one-year-old potted grapevine cuttings (‘Barbera’). All isolates (except N. juglandicola) caused brown wood necrotic vascular discolourations on inoculated plants and were successfully re-isolated. Effects of temperature on colony growth were also assessed. For all tested isolates there was no growth at 5°C, only four isolates (Botryosphaeriaceae) grew at 35°C, and optimum growth temperatures were between 20 and 25°C. This is the first record of Paraconiothyrium brasiliense and Neocucurbitaria juglandicola associated with symptomatic grapevines in Italy.

Whole-genome sequencing and functional annotation of pathogenic Paraconiothyrium brasiliense causing human cellulitis

BackgroundA pathogenic filamentous fungus causing eyelid cellulitis was isolated from the secretion from a patient's left eyelid, and a phylogenetic analysis based on the rDNA internal transcribed spacer region (ITS) and single-copy gene families identified the isolated strain as Paraconiothyrium brasiliense. The genus Paraconiothyrium contains the major plant pathogenic fungi, and in our study, P. brasiliense was identified for the first time as causing human infection. To comprehensively analyze the pathogenicity, and proteomics of the isolated strain from a genetic perspective, whole-genome sequencing was performed with the Illumina NovaSeq and Oxford Nanopore Technologies platforms, and a bioinformatics analysis was performed with BLAST against genome sequences in various publicly available databases.ResultsThe genome of P. brasiliense GGX 413 is 39.49 Mb in length, with a 51.2% GC content, and encodes 13,057 protein-coding genes and 181 noncoding RNAs. Functional annotation showed that 592 genes encode virulence factors that are involved in human disease, including 61 lethal virulence factors and 30 hypervirulence factors. Fifty-four of these 592 virulence genes are related to carbohydrate-active enzymes, including 46 genes encoding secretory CAZymes, and 119 associated with peptidases, including 70 genes encoding secretory peptidases, and 27 are involved in secondary metabolite synthesis, including four that are associated with terpenoid metabolism.ConclusionsThis study establishes the genomic resources of P. brasiliense and provides a theoretical basis for future studies of the pathogenic mechanism of its infection of humans, the treatment of the diseases caused, and related research.

New Fungal Strains from Peat Soil in Malaysia: Morphological and Molecular Characteristics

Fungi have unique properties and are used in many areas of agriculture and industry because they can produce different enzymes. This study aims to study the fungal diversity in peat soil from Pontian in Johor, Malaysia. The fungal isolates were described on different culture media and on a new culture medium called EVA medium and were identified using the phenotypical characteristics and molecular properties of the D1/D2 domain of the 28S large subunit ribosomal RNA (28S rRNA) and ITS (ITS1-ITS4) rDNA regions. The results revealed that 14 fungal species (15 isolates) were identified, among them, 6 were categorized as newly isolated strains and recorded in Malaysia; these include Aspergillus arenarioides EAN603, A. iizukae EAN605, Paraconiothyrium brasiliense EAN202, Parengyodontium album EAN602, Penicillium pedernalense EAN604, and Purpureocillium lilacinum EAN601. The cultural, morphological, microstructure, and molecular characteristics of these new strains have been described in this study. It was noted that the EVA medium exhibited a moderate support for fungal growth and sporulation compared to other culture media. Furthermore, the efficiency of the new medium as an enrichment medium to isolate fungi from peat soils with high ligninolytic content was discussed.

Brasilterpenes A-E, Bergamotane Sesquiterpenoid Derivatives with Hypoglycemic Activity from the Deep Sea-Derived Fungus Paraconiothyrium brasiliense HDN15-135.

Five bergamotane sesquiterpenoid derivatives, brasilterpenes A–E (1–5), bearing an unreported spiral 6/4/5 tricyclic ring system, were isolated from the deep sea-derived ascomycete fungus Paraconiothyrium brasiliense HDN15-135. Their structures, including absolute configurations, were established by extensive spectroscopic methods complemented by single-crystal X-ray diffraction analyses, electronic circular dichroism (ECD), and density-functional theory (DFT) calculations of nuclear magnetic resonance (NMR) data including DP4+ analysis. The hypoglycemic activity of these compounds was assessed using a diabetic zebrafish model. Brasilterpenes A (1) and C (3) significantly reduced free blood glucose in hyperglycemic zebrafish in vivo by improving insulin sensitivity and suppressing gluconeogenesis. Moreover, the hypoglycemic activity of compound 3 was comparable to the positive control, anti-diabetes drug rosiglitazone. These results suggested brasilterpene C (3) had promising anti-diabetes potential.

Combination of Paraconiothyrium brasiliense fabricated titanium dioxide nanoparticle and antibiotics enhanced antibacterial and antibiofilm properties: A toxicity evaluation

Antimicrobial resistance (AMR) causes global consequences through increased mortality and economic loss. Antimicrobial drugs including nanomaterials are an emerging environmental impact. Hence, this work aimed to synthesize and characterize the titanium dioxide nanoparticles (TiO2 NPs) using the aqueous extract of endophytic fungus Paraconiothyrium brasiliense (Pb) for enhancing the antibacterial efficiency of existing standard antibiotics at minimum concentration. The FTIR and XRD results confirmed the capping of functional molecules and the crystalline nature of Pb–TiO2 NPs. The spherical-shaped TiO2 NPs with the size of 57.39 ± 13.65 nm were found in TEM analysis. The average hydrodynamic size (68.43 ± 1.49 d. nm) and the zeta potential (−19.6 ± 1.49 mV) was confirmed the stability of Pb–TiO2 NPs. Antibacterial studies revealed that bare Pb–TiO2 NPs (20 μg/mL) did not exhibit significant antibacterial activity while combination of TCH + Pb–TiO2 NPs considerably increased the inhibition of E. coli biofilm evidenced by CLSM and SEM analysis. Further, Pb–TiO2 NPs (100 μg/mL) were found to be moderately toxic to cell line (NIH3T3), red blood cells (RBC), and egg embryos. Hence, this study concluded that <50 μg/mL of TiO2 NPs can be mixed with antibiotics for enhanced antibacterial application thereby minimizing the AMR and the environmental toxicity.

Fungi from Galleries of the Emerald Ash Borer Produce Cankers in Ash Trees

The emerald ash borer (EAB, Agrilus planipennis) is a devastating invasive pest that has killed millions of ash trees in the United States and Canada. EAB was discovered in the US in 2002 and first reported in Minnesota in 2009. It attacks ash trees that are native to the United States, including Fraxinus americana (white ash), F. nigra (black ash) and F. pennsylvanica (green ash). It also attacks Chionanthus virginicus (white fringe tree). Seven species of fungi isolated and identified only from EAB-infested trees in a previous study as having the potential to cause cankers were used to test their pathogenicity in F. americana (white ash). The fungi used were Cytospora pruinosa, Diplodia mutila, Diplodia seriata, Paraconiothyrium brasiliense, Phaeoacremonium minimum, Phaeoacremonium scolyti, and Thyronectria aurigera. Two field experiments that used F. americana used two inoculation methods: woodchip and agar plug inoculations. Results indicated that all of the fungi tested caused cankers in varying amounts, as compared to the controls. The largest cankers were caused by D. mutila (270 mm2), C. pruinosa (169 mm2), and D. seriata (69 mm2). All fungi except for T. aurigera were re-isolated and sequenced to confirm Kochs’ postulates. Canker-causing fungi found in association with EAB galleries have the potential to contribute to tree dieback and mortality.

Antibacterial activity of ethyl acetate extract of endophytic fungus (Paraconiothyrium brasiliense) through targeting dihydropteroate synthase (DHPS)

Endophytic fungi are innumerable sources of bioactive metabolites with various biomedical applications. Hence, this study was aimed to isolate and identify the endophytic fungus Paraconiothyrium brasiliense (PB) from the fruit of Capsicum annuum and evaluated their biochemical, antimicrobial, antioxidant, cell viability, and cytotoxicity behavior. Results showed that ethyl acetate extract (EAE) of PB contains flavonoid (31.53 ± 0.9 mg of QE/g of extract) and phenolic (2.59 ± 0.06 mg of GAE/g of extract). The PB-EAE showed significant antioxidant activity in terms of free radicals (DPPH, ABTS, and Fe3+) scavenging. The antioxidant potential of PB-EAE reflects in normal cell viability and anticancer activity against prostate cancer (PC3) cells. The bacterial inhibitory activity of PB-EAE was equal to commercial antibiotic tetracycline hydrochloride (TCH). Further, GC–MS analysis confirmed the presence of volatile molecules such as o-cymene (CH3C6H4CH(CH3)2), dipentene (C10H16), γ-terpinene (C10H16), 4-carvomenthenol (C10H18O), heneicosane (CH3(CH2)19CH3), and 2,5-piperazinedione (C4H6N2O2). Also, molecular docking analysis demonstrated the significant interactions between the compounds of PB-EAE with dihydropteroate synthase (Protein ID:5JQ9; DHPS). This study revealed that endophytic P. brasiliense could be a novel source for isolation of antimicrobials.

First Report of Didymosphaeria rubi-ulmifolii Brown Spot infection of Chinese quince fruit in South Korea.

Chinese quince (Pseudocydonia sinensis (Thouin) CK Schneid.), a deciduous tree in the family Rosaceae, is native to China, Japan, and South Korea; the fruit is known as mogwa in South Korea. The ripened yellow fruit has been used as a traditional therapeutic for respiratory ailments and as an additive in health products such as syrups, tea, and candies (Sawai et al. 2008). From May to August 2020, Chinese quince trees showing symptoms of brown spots were observed on the Kyungpook National University premises, Daegu, South Korea, with an incidence of 30%-40%. The disease first appeared as small, round, yellow specks on the fruits, which necrotized over time and gradually enlarged to 0.7-2.7 cm in diameter. To isolate the pathogen, symptomatic tissues obtained from disease fruit were surface sterilized for 1 min with 70% ethanol, rinsed in sterile distilled water, and plated onto potato dextrose agar (PDA). The inoculated plates were incubated at 25°C for 7 days. Successively, pure cultures were obtained by transferring hyphal tips to new PDA plates. Twenty isolates were obtained from 25 fruit. Colonies on PDA reached a diameter of 30-40 mm. After incubation for 7 days at 25°C, spreading with an even, colorless-to-buff glabrous margin, a submarginal ring of conidiomata developed from day 5 to 12 and was visible as scattered dots on either side of the plate. Conidiogenous cells were discrete (3.5-6 × 3.5-5 μm); conidia were ellipsoid to short-cylindrical [3-5 × 2.1-3.5 μm (n = 60)] and olivaceous in color. These conidial dimensions corresponded to those of Didymosphaeria rubi-ulmifolii Ariyaw., Camporesi & K.D. Hyde (basionym: Paraconiothyrium brasiliense), which has been found on Rubus ulmifolius in Italy (Ariyawansa et al. 2014). Sequence data for the rDNA internal transcribed spacer (ITS), large subunit ribosomal RNA (LSU), and partial translation elongation factor 1-α (TEF) (White et al. 1990, Rehner and Buckley 2005) were obtained for one of the pure culture isolate (BT1) with GenBank accession numbers MW020087, MW020060 and MW027220, respectively. The sequences of BT1 isolate using a BLASTn analysis showed 100% identity with the ex-type MFLUCC 14-0023 of D. rubi-ulmifolii in ITS, and LSU portions (accession nos. MT310602, and MT214555, respectively) and 99% identity in TEF portion (accession no. MT394734). The procedure for Koch's postulates was followed to confirm fungal pathogenicity using 3-day-old mycelial discs. Fifteen healthy fruit were divided into three groups of five fruit each, with each group receiving a different treatment. One group of fruit was wounded by puncturing with a sterile pin and inoculated using 5-mm agar discs with mycelium on the wounds. Mycelium covered agar discs were also placed on the surfaces of five unwounded fruits. The remaining five fruit were maintained as a control and inoculated with sterile PDA plugs. The pathogenicity test was replicated thrice. The wounded fruits showed symptoms similar to those observed in the field. The control group remained asymptomatic and the morphology of the fungus re-isolated from the inoculated fruit was the same as that of D. rubi-ulmifolii. The phylogeny, together with the morphological identification and inoculation results, confirmed the identity of the fungus as D. rubi-ulmifolii (Ariyawansa et al. 2014). To the best of our knowledge, this is the first report of D. rubi-ulmifolii causing brown spot in Chinese quince.

First Report of Didymosphaeria rubi-ulmifolii Causing Wood Rot of Peach (Prunus persica) in China

China is the largest producer of peaches (Prunus persica) in the world, with an annual yield accounting for over 50% of the world peach product. In January 2019, a severe wood rot disease of peach was observed in Hefei City, Anhui Province of China. Mean disease incidence was estimated as 10% in 5-ha orchards. Typical symptoms were characterized by wood internal vascular discoloration and canker on stems. Seven samples were collected from symptomatic stems of peach trees and cut to small pieces (4 × 4 mm) from the margin of the lesions, and they were surface disinfected in 75% ethanol for 20 s and 2% NaClO for 1 min, followed by rinsing three times with sterilized water, placed on potato dextrose agar (PDA), and incubated at 25°C. In total, six representative fungal colonies were isolated from infected stems on PDA medium and named as GF1 to GF6. Colonies on PDA showed brown at the early stages and turned to black after 5 days. Conidia were ellipsoid or short cylindrical, continuous, sometimes separate, olivaceous, and 3.4 to 4.6 × 2 to 2.3 μm. Total DNAs of the three isolates were extracted for PCR sequencing using primers for the rDNA internal transcribed spacer (ITS) (ITS1/ITS4, ITS1/ITS2, and ITS4/ITS5) and TUB2 (βT2a/βT2b) (Arredondo-Santoyo et al. 2018; Damm et al. 2008). ITS sequences (MN932144, MN947626, and MN944552) and TUB2 (BankIt2303021) were deposited in GenBank. BLAST searches showed ITS sequences had over 99.65% sequence similarity with Paraconiothyrium brasiliense strain KH1W (MK779925.1), STE-U 6300 (EU295651.1), and CBS 254.88 (JX496058.1), respectively. The sequences of TUB2 showed 97.98% similarity with P. brasiliense TUB2 sequences (LT796975.1). Based on the morphological and molecular analysis (Verkley et al. 2004), we confirmed the newly isolated strains belong to Didymosphaeria rubi-ulmifolii (basionym: P. brasiliense) (Ariyawansa et al. 2014). Pathogenicity trials were conducted on 5-year-old P. persica trees. Two-year-old healthy shoots were surface sterilized with 70% ethanol. Conidial suspension (50 μl, 5 × 10⁶ conidia/ml) was added into the wound (a hole of 2 to 2.5 mm deep). Control branches were treated with sterilized water. The inoculated plants were maintained at 25 ± 3°C with 95% humidity for 14 days. All those treated with isolates showed lesions of branches, but not the water-treated control plants. Reisolation was performed from symptomatic branches, and their identities were confirmed using the above-mentioned methods. All tests were performed three times, and pathogenicity tests employed five plants for each strain. To our knowledge, this is the first report of D. rubi-ulmifolii causing canker disease on peach species in China.

Paraconiothins A-J: Sesquiterpenoids from the Endophytic Fungus Paraconiothyrium brasiliense ECN258.

Paraconiothins A-J (1-10), 10 new sesquiterpenoids, as well as five known sesquiterpenoids, were isolated from the cultures of the endophytic fungus Paraconiothyrium brasiliense ECN-258. The structures of the sesquiterpenoids were elucidated by extensive spectroscopic analysis. Furthermore, the absolute structures of 7 and 8 were determined by comparing their experimental and computed electronic circular dichroism data. Paraconiothins A-G (1-7) were eremophilane sesquiterpenoids, while paraconiothins H-J (8-10) had new or rare carbon frameworks that are possibly biosynthesized by a pathway involving the rearrangement of eremophilane sesquiterpenoids. Paraconiothins C (3) and I (9) exhibited an inhibitory effect on the liver X receptor α at a concentration of 50 μM.

First report of leaf spot of Sarcococca saligna caused by Paraconiothyrium brasiliense in Pakistan

First report of leaf spot of Sarcococca saligna caused by Paraconiothyrium brasiliense in Pakistan

Elicitors derived from endophytic fungi Chaetomium globosum and Paraconiothyrium brasiliense enhance paclitaxel production in Corylus avellana cell suspension culture

Paclitaxel is an impressive chemotherapeutic agent that shows biological activity against a wide range of cancers. Cell suspension culture of Corylus avellana has been reported as an alternative source for production of the valuable secondary metabolite, paclitaxel. The fungal elicitors have been considered as the most impressive strategy for enhancement of secondary metabolites in plant cell culture. In this study, two endophytic fungal strains YEF20 and HEF114 were isolated from Taxus baccata and C. avellana, respectively. The isolates YEF20 and HEF114 were identified as Chaetomium globosum and Paraconiothyrium brasiliense, respectively by sequencing of ITS1-5.8S-ITS2 rDNA region. This is the first report of P. brasiliense on C. avellana tree. Also, this study presents the positive effect of fungal elicitors on paclitaxel production in C. avellana for the first time. The effect of fungal elicitors on paclitaxel production was dependent on fungal species, and also type, concentration and adding time of elicitors to cell culture. The highest total yield of paclitaxel in cell culture treated with cell extract (CE) of C. globosum (291.5 µg L−1) was obtained by using 10% (v/v) of this fungal elicitor on 17th day of cell culture cycle (late log-phase), which was about 4.1 times obtained in the control culture. The cell culture treated with C. globosum CE had an average growth rate of 0.491 g L−1 day−1, i.e. 12.3% lower than that in the control. Among the fungal elicitors, 10% (v/v) CE of C. globosum on 17th day of culture cycle showed the best results with respect to extracellular paclitaxel portion (44.0%). Paclitaxel secretion to culture medium is essential for large-scale steady production of paclitaxel.

Identification and characterization of the biotechnological potential of a wild strain of Paraconiothyrium sp.

The isolation and characterization of fungal strains from poorly described taxa allows undercover attributes of their basic biology useful for biotechnology. Here, a wild fungal strain (CMU-196) from recently described Paraconiothyrium genus was analyzed. CMU-196 was identified as Paraconiothyrium brasiliense by phylogenetic analysis of the rDNA internal transcribed spacer region (ITS). CMU-196 metabolized 57 out of 95 substrates of the Biolog FF microplates. Efficient assimilation of dextrins and glycogen indicates that CMU-196 is a good producer of amylolytic enzymes. It showed a remarkably assimilation of α-d-lactose, substrate described as inducer of cellulolytic activity but poorly assimilated by several fungi. Metabolically active mycelium of the strain decolorized broth supplemented with direct blue 71, Chicago sky blue and remazol brilliant blue R dyes. The former two dyes were also well removed from broth by mycelium inactivated by autoclaving. Both mycelia had low efficiency for removing fuchsin acid from broth and for decolorizing wastewater from the paper industry. CMU-196 strain showed extracellular laccase activity when potato dextrose broth was supplemented with Cu+2 , reaching a maximum activity of 46.8 (±0.33) U L-1 . Studied strain antagonized phytopathogenic Colletotrichum spp. fungi and Phytophthora spp. oomycetes in vitro, but is less effective towards Fusarium spp. fungi. CMU-196 antagonism includes overgrowing the mycelia of phytopathogens and growth inhibition, probably by hydrosoluble extracellular metabolites. The biotechnological potential of strain CMU-196 here described warrants further studies to have a more detailed knowledge of the mechanisms associated with its metabolic versatility, capacity for environmental detoxification, extracellular laccase production, and antagonism against phytopathogens. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:846-857, 2018.

Two New Polyketide Metabolites Isolated from Paraconiothyrium brasiliense

Two new polyketide metabolites, named ethyl 8-hydroxy-9-oxo-9H-xanthene-1-carboxylate (1) and 1,8-dihydroxy-2-(1-hydroxyethyl)anthracene-9,10-dione (2), along with six known compounds, were isolated from the fungus Paraconiothyrium brasiliense. The structures of the new compounds were elucidated on the basis of 1D and 2D NMR experiments.

Design and synthesis of natural product derivatives with selective and improved cytotoxicity based on a sesquiterpene scaffold

Brasilamide E (1) is a bisabolane sesquiterpenoid isolated from the solid-substrate fermentation cultures of a plant endophytic fungus Paraconiothyrium brasiliense. The compound specifically inhibited proliferation of the MCF-7 cells, but did not show cytotoxicity towards the negative controls HaCaT and NIH3T3 cells (IC50>50μM). To improve its potency while maintain selectivity, a total of 27 derivatives of 1 were designed, synthesized, and evaluated for in vitro cytotoxicity against six tumor cell lines and the negative control NIH3T3 cells. Among these compounds, compound 12b showed significantly improved potency against the MCF-7, HeLa, and HO8910 cells with IC50 values of 0.13–0.25μM compared to 1 (IC50 8.47–18.00μM), and remained nontoxic to the NIH3T3 cells.

First Record of Endophytic Paraconiothyrium brasiliense Isolated from Chinese Maple Leaves in Korea

The fungal endophyte EML-CM25 was isolated in Korea from surface sterilized Chinese maple leaf tissues. Internal transcribed spacer sequence analysis indicated that the isolate showed 99% sequence similarity with Paraconiothyrium brasiliense, a finding that was confirmed by morphological analyses. The fungal colonies did not express aerial hyphae. Conidiomata formation was observed in the fungus cultured on potato dextrose agar at 25 o C for 7 days. Visible scattered black dots consisting of pycnidia were present throughout the colony. This is the first record of P. brasiliense in Korea.

가든식물 수호초(Pachysandra terminalis)로부터 Paraconiothyrium brasiliense의 분리 및 동정

수호초로부터 분리된 DUCC5000 균주를 형태적, 분자생물학적 분류를 통해 Paraconiothyrium brasiliense로 동정하였다. 본 균은 기존에 알려진 P. brasiliense 균주의 ITS 염기서열과 100%의 상동성을 보였다. 계통유전학적 분석 결과 P. brasiliense 균주와 같은 clade를 형성하였다. 서로 다른 영양 배지와 pH 조건 하에서 균사생육 특성을 조사한 결과 oatmeal agar 배지와 pH 9에서 최적의 생장을 보였다. 배지 종류에 따라 그리고 pH 조건에 따라 균총 형태가 달라지는 특성을 지니고 있었다. Chroma 반응배지를 이용하여 7가지 세포외 효소의 분비 능력을 조사한 결과 <TEX>${\beta}$</TEX>-glucosidase 활성이 가장 활발하였고 CM-cellulase와 xylerase에서는 활성이 미약하였다. 인공 접종하였으나 수호초에 대한 병원성은 나타내지 않았다. 본 균은 수호초에서는 국제적으로 처음 보고되는 균이다. A fungal isolate DUCC5000 from a garden plant Pachysandra terminalis was identified as Paraconiothyrium brasiliense based on the results of morphological and molecular studies. The fungus formed brown to black conidiomata of (0.2-0.7)-2(-3.5) mm singly or as a group on PDA. Conidia measured <TEX>$2-5{\times}1.8-3{\mu}m$</TEX> in size, hyaline, ellipsoid to short-cylindrical, and rounded at both ends. The internal transcribed spacer (ITS) DNA of the isolate shared 100% nucleotide sequence homology with those of known P. brasiliense isolates. Phylogenetic tree inferred from the ITS sequence analysis showed that the DUCC5000 isolate formed a clade with known isolates of P. brasiliense. The fungal mycelia grew better on oatmeal agar than on MEA and PDA. On PDA media under various pH conditions, fungal mycelial growth was observed at pH 9. Colony morphology of the fungus tended to alter depending on the kinds of nutrient media and pH condition. On chromagenic media, the fungus demonstrated its ability to produce extracellular enzymes including amyalse, avicelase, <TEX>${\beta}$</TEX>-glucosidase, protease, and xylanase. However, in pathogenicity testing, no disease symptoms were observed on the leaves of P. terminalis. This strain is the first report on P. terminalis in Korea.