Fungal–copper interactions in wood examined with large field of view synchrotron-based X-ray fluorescence microscopy

ABSTRACT

The goal of this study was to demonstrate how synchrotron-based X-ray fluorescence microscopy (XFM) can be used to better understand the mechanisms of copper tolerance in wood decay fungi. Copper is a major component in commercial wood preservatives as it is toxic to many wood decay fungi. However, certain fungi are copper tolerant and can attack preservative-treated wood, resulting in structural damage to treated wood members. Here we used large-field XFM to visualize six different elements (K, Ca, Mn, Fe, Cu, and Zn) in the mycelia and wood inoculated with four different species of brown rot wood decay fungi. Wood blocks were partially dipped into a solution of copper sulfate, exposed to fungi in malt extract agar petri dish assays for nine weeks, and then imaged and compared to blocks that were partially dipped in water. The blocks were imaged immediately adjacent to an end-matched control that was placed in malt extract agar petri dish assays for 9 weeks, but not exposed to the fungi so that the differences in the elemental distributions could be directly compared. The colonized wood and mycelia were rich in K, Ca, Mn, and Fe; however, the elements and the spatial distribution in the mycelia and wood differed across fungal species. The most interesting results were the maps showing the copper distribution. While three of the four fungi grew on the copper-rich region of the wood, only one species, Fibroporia radiculosa, dramatically reduced the copper concentration in the region of fungal growth.     

籼、粳超级稻光合物质生产与转运特征的差异研究

为阐明籼、粳超级稻干物质积累及光合生产特征的差异,以江苏地区大面积推广种植的5个超级杂交籼稻组合和5个常规粳型超级稻品种为试验材料,对稻麦两熟制条件下籼、粳超级稻干物质积累、分配、运转及叶面积、光合势、群体生长率、净同化率、秧苗素质、叶型等方面进行了系统的比较研究。结果表明,粳稻生育前期(移栽至拔节期)干物质积累量、光合势、群体生长率、净同化率及上三叶叶长、叶基角、叶开角、披垂度和叶面积衰减率、收获指数均小于籼稻,而生育中后期(拔节至成熟期)干物质积累量、光合势、群体生长率、净同化率及有效叶面积率、高效叶面积率、粒叶比(颖花/叶、实粒/叶、粒重/叶)、最大叶面积指数、总充实量、实收产量、生物产量、茎鞘最大输出量和表观输出量及比率均大于籼稻,差异显著或极显著。虽然粳稻主要生育期单茎干物重均不及籼稻,但群体数量优势保证粳稻具有较高的群体干物质积累量和叶面积,且随着生长发育的持续,群体光合物质生产优势不断加大,群体干物质积累量于抽穗后25 d前后超过籼稻。粳稻灌浆后期(乳熟至成熟期)仍保持强劲生长优势,而灌浆初期(抽穗至乳熟期)茎鞘贮存物质合理输出,有效保障了高效光合层的安全支撑及高积累产量库的流畅充实。高生物学产量的稳定形成和叶面积“稳升缓降”态势以及拔节至成熟期较强的高效光合物质生产,是粳稻光合系统高效持续产出、灌浆充实多及高产形成的重要特征和原因。     

Mechanism of AKT1 negatively regulating breast cancer cell migration

AIM: To investigate the molecular mechanism and downstream signaling pathway by which AKT1 inhibition regulates breast cancer cell migration. METHODS: RNA interference was used to knockdown the expression of AKT1. Western blot assay was performed to examine the expression of AKT1 total protein, β-catenin total protein and β-catenin nuclear protein. Immunofluorescence was used to examine the cellular localization of β-catenin. Transwell assay was used to investigate whether β-catenin nuclear accumulation as an alternative pathway was responsible for breast cancer metastasis induced by AKT1 inhibition. RESULTS: The total protein expression of AKT1 was decreased in MCF-7 and MDA-MB-231 cells treated with AKT1 siRNA. A significant increase in the protein expression of β-catenin was observed in MCF-7 cells and MDA-MB-231 cells treated with AKT1 siRNA. Immunofluorescence staining showed that MCF-7 cells and MDA-MB-231 cells displayed strong β-catenin staining in the cytoplasm and nucleus after knockdown of AKT1 expression. The ability of tumor cell migration increased dramatically after treated with AKT1 specific siRNA in the breast cancer MCF-7 cells and MDA-MB-231 cells in Transwell assay. XAV-939 reversed breast cancer cell migration induced by knockdown of AKT1 expression. CONCLUSION: β-catenin nuclear accumulation contributes to AKT1 inhibition-mediated breast cancer cell migration.     

一个普通小麦-大赖草易位系T01的选育与鉴定

将抗赤霉病的普通小麦-大赖草Lr.2染色体单体异附加系花粉经过60Co-γ射线处理, 然后给感赤霉病的普通小麦品种“扬麦5号”授粉, 杂交后代连续2年进行赤霉病抗性单株接种鉴定, 从中选育出一个普通小麦-大赖草异易位系。 经过染色体荧光原位杂交和Giemsa C-分带鉴定, 易位发生在普通小麦4B染色体长臂和大赖草第2条染色体(L     

铅在砂壤水稻土/水稻体系中污染效应及累积规律的研究

通过盆栽试验,研究了吉林省砂壤水稻土中铅地水稻的毒性效应及在土壤／２体系中的残留积累规律。结果表明：土壤中添加铅１８０～７２０ｍｇ／ｋｇ条件下,对水稻生长的毒害作用不大。可使水稻减产２％～１７％。水稻各器官铅累积量随土壤中铅浓度的增加而增加,其分布规律为：根〉〉茎叶〉糙米。以食品卫生标准为依据,计算出砂壤水稻土中铅的全量、提取量毒性临界值分别为２４１ｍｇ／ｋｇ和４９ｍｇ／ｋｇ。