Dioxopiperazine Alkaloids Produced by the Marine Mangrove Derived Endophytic Fungus Eurotium rubrum

Cultivation of the fungal strain Eurotium rubrum, an endophytic fungus that was isolated from the inner tissue of stems of the mangrove plant Hibiscus tiliaceus, resulted in the isolation of two new dioxopiperazine derivatives, namely, dehydrovariecolorin L (1) and dehydroechinulin (2), together with eight known dioxopiperazine compounds including variecolorin L (3), echinulin (4), isoechinulin A (5), dihydroxyisoechinulin A (6), preechinulin (7), neoechinulin A (8), neoechinulin E (9), and cryptoechinuline D (10). The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature. Compounds 1, 2, 9, and 10 were investigated for their a,a-diphenyl-beta-picrylhydrazyl (DPPH) radical-scavenging activity. In addition, the new compounds, 1 and 2, were evaluated for their cytotoxic activity against the P-388, HL-60, and A549 cell lines.

两株海藻内生真菌次生代谢产物及其生物活性研究

海洋微生物拥有丰富多样的次生代谢途径，其中海洋生物内生真菌次生代谢产物研究日益受到天然产物化学界的重视。本论文以菌丝体生物量、发酵产物重量、抗菌与细胞毒活性、薄层色谱分析结果以及高效液相色谱分析结果等为评价依据对采自青岛沿海的13株海藻内生真菌在四种液体培养基上的静置发酵产物进行了综合评价，并从中选择了黑曲霉Aspergillus niger EN-13（分离自褐藻囊藻Colpomenia sinuosa）和杂色曲霉A. versicolor EN-7（分离自褐藻鼠尾藻Sargassum thunbergii）两株真菌进行了30升规模发酵（分别采用GPYM培养基和PDB培养）和化学成分的研究，对分离得到的大部分化合物进行了初步的生物活性筛选。 发酵提取物采用常规的硅胶柱层析、反相硅胶柱层析，凝胶Sephadex LH-20柱层析、制备薄层层析、半制备高效液相色谱以及重结晶等分离手段，得到单体化合物。利用各种现代波谱技术(IR、UV、EI-MS、FAB-MS、HR-ESI-MS、1H-NMR、13C-NMR、DEPT、1H-1H COSY、HSQC、HMBC等)并结合化学方法从两种菌株发酵提取物中鉴定了55个化合物的结构。其中从菌株A. niger EN-13分离鉴定了31个化合物，发现9个新化合物，包括2个鞘酯类化合物（AN-1~2）、3个萘并-γ-吡喃酮类化合物（AN-3~5）、3个苯乙基取代的α-吡喃酮类化合物（AN-17, AN-19~20）和1个甾体Diels-Alder加成产物（AN-21），另有1个新的天然环二肽（AN-27）被分离鉴定；从菌株A. versicolor EN-7分离鉴定了24个化合物，发现2个新化合物，为蒽醌AV-12与AV-17，另外，从前一菌株（A. niger EN-13）中鉴定的2个新鞘酯类化合物（AN-1~2）在A. versicolor EN-7中也被再次分离到。 对大部分单体化合物进行了抗菌活性、DPPH自由基清除活性和细胞毒活性测试。结果显示新化合物AN-1、AN-5和AN-20具有弱或中等强度的抑制白色念珠菌生长的活性，AN-4、AN-5、AN-21显示了弱或中等强度的抑制黑曲霉生长的活性，AV-12、AV-17显示了弱的抑制大肠杆菌生长的活性。在DPPH自由基清除活性筛选中，AN-5显示了中等强度的活性，其EC50为109.3 mM，与阳性对照BHT相近（EC50为81.8 mM）。其它部分已知化合物在抗菌和DPPH自由基清除活性的筛选中也显示了弱或中等强度的活性。在针对人肝癌细胞株SMMC-7721和人肺腺癌细胞株A549的体外细胞毒活性筛选中，所测样品均未显示显著活性。

Possible suppression of exogenous beta-1,3-glucanase gene gluc78 on rice transformation and growth

Three genes encoding for fungal cell wall degrading enzymes (CWDE), ech42, nag7O and gluc78 from the biocontrol fungus Trichoderma atroviride were transformed into rice mediated by Agrobacterium tumefaciens singly and in all possible combinations. A total of more than 1800 independently regenerated plantlets in seven different populations (for each of the three genes and each of the four gene combinations) were obtained. Our data indicated that gluc78 gene had negative effects on transformation frequency and plant growth. Some regenerated plants with gluc78 gene were stunted; spontaneously produced brown specks; could not tassel. The combination with either one of the two other genes (ech42, nag70) present in the same T-DNA region reduced the negative effect of gluc78 on plant growth. These results indicated that expression of several genes in one T-DNA region interfered with each other and expression of exogenous gene in recipient plant was a complex behavior. (c) 2007 Published by Elsevier Ireland Ltd.

Doenças de final de ciclo são favorecidas pelo clima.

2010

Thap maeo e Caipira: cultivares de bananeira resistentes a sigatoka negra, para o Estado do Amazonas.

Selecao das cultivares Thap maeo e Caipira para recomendacao aos produtores amazonenses, envolvendo: a) caracteristicas e recomendacoes para Thape maeo e Caipira; b) espacamento e densidade populacional; c) adubacao, para as condicoes edafoclimaticas e Manaus-AM (Brasil).

Mancha foliar do coqueiro causada por Bipolaris incurvata.

Descricao dos sintomas da mancha foliar do coqueiro, causada por Bipolaris incurvata. Como medida de controle, e recomendado efetuar a correcao do solo com calcario dolomitico e prover adubacoes adequadas, principalmente com materia organica e potassio, na cova de plantio, dentre outras medidas.

Epidemiologia da vassoura-de-bruxa (Crinipellis perniciosa) do cupuacuzeiro (Theobroma grandiflorum).

Determinacao dos periodos mais favoraveis a ocorrencia da vassoura-de-bruxa, envolvendo a fenologia do hospedeiro, na esporulacao do fungo e nas condicoes climaticas de Manaus, AM (Brasil).

Importancia da analise sanitaria de sementes para o manejo da esclerotinia no cerrado.

2001

Ferrugem e mancha-foliar em milheto (Pennisetum glaucum) no cerrado do Brasil Central.

2001

Repetibilidade de caracteres fenotípicos e distâncias genéticas em aveia em experimentos com e sem fungicida.

2006

Podridão vermelha da raiz (Fusarium solani) e mofo branco (Sclerotinia sclerotiorum) na cultura da soja.

2008

Ocorrência de Phoma multirostrata em baru (Dipteryx alata) no Cerrado.

2008

Bipolaris maydis causando manchas foliares em capim-elefante no Brasil Central.

2008

Epidemiologia da sigatoka negra da bananeira (Musa spp).

Estudo sobre o progresso da sigatoka negra em bananeiras, associado a variacoes e/ou efeitos de variaveis climaticas, que permitem prever as epocas de maior severidade e/ou surtos da doenca, de forma a estabelecer estrategias de controle mais viaveis do ponto de vista economico-ambiental no Estado do Amazonas (Brasil).

Eficiência de fungicidas multissítios e fertilizantes no controle da ferrugem asiática da soja, Phakopsora pachyrhizi, na safra 2014/15: resultados sumarizados dos ensaios cooperativos.

2015