Chronic exposure to increasing background ozone impairs stomatal functioning in grassland species

Two species found in temperate calcareous and mesotrophic grasslands (Dactylis glomerata and Leontodon hispidus) were exposed to eight ozone treatments spanning preindustrial to post‐2100 regimes, and late‐season effects on stomatal functioning were investigated. The plants were grown as a mixed community in 14 L containers and were exposed to ozone in ventilated solardomes (dome‐shaped greenhouses) for 20 weeks from early May to late September 2007. Ozone exposures were based on O₃ concentrations from a nearby upland area, and provided the following seasonal 24 h means: 21.4, 39.9 (simulated ambient), 50.2, 59.4, 74.9, 83.3, 101.3 and 102.5 ppb. In both species, stomatal conductance of undamaged inner canopy leaves developing since a midseason cutback increased linearly with increasing background ozone concentration. Imposition of severe water stress by leaf excision indicated that increasing background ozone concentration decreased the ability of leaves to limit water loss, implying impaired stomatal control. The threshold ozone concentrations for these effects were 15–40 ppb above current ambient in upland UK, and were within the range of ozone concentrations anticipated for much of Europe by the latter part of this century. The potential mechanism behind the impaired stomatal functioning was investigated using a transpiration assay. Unlike for lower ozone treatments, apparently healthy green leaves of L. hispidus that had developed in the 101.3 ppb treatment did not close their stomata in response to 1.5 μm abscisic acid (ABA); indeed stomatal opening initially occurred in this treatment. Thus, ozone appears to be disrupting the ABA‐induced signal transduction pathway for stomatal control thereby reducing the ability of plants to respond to drought. These results have potentially wide‐reaching implications for the functioning of communities under global warming where periods of soil drying and episodes of high vapour pressure deficit are likely to be more severe.     

NMR-based metabonomic analysis on effect of light on production of antioxidant phenolic compounds in submerged cultures of Inonotus obliquus

This study was designed to investigate the light effect on biosynthesis of antioxidant phenolic compounds by Inonotus obliquus grown in submerged cultures using ¹H NMR spectroscopy combining multivariate pattern recognition strategies. I. obliquus were exposed to a range of light conditions and resultant data were compared to those from field-grown sclerotia and the mycelia grown in daylight. Daylight illumination inhibited biosynthesis of davallialactone and phelligridins and other hispidin analogs. Continuous darkness enhanced the formation of phelligridins, davallialactone and inoscavins. Phelligridins and davallialactone also occurred in the mycelia grown in blue and red light with levels lower than those found in darkness. In addition, polyphenols synthesized under daylight conditions showed less potential antioxidant activity than those determined with other light regimes. These findings demonstrate that light regulates biosynthesis of polyphenols in I. obliquus and their subsequent antioxidant activities, and ¹H NMR-based metabolic profiling is a cost-effective approach for evaluating light effects on fungal metabolisms.     

粗毛纤孔菌子实体与菌丝体粗多糖改善小鼠急性酒精肝损伤的比较研究

粗毛纤孔菌是一种常见的药用真菌,具有医疗保健价值,多糖作为其主要活性成分之一,在生物活性中发挥着重要的作用。本文从粗毛纤孔菌子实体和菌丝体中提取了多糖成分,探讨了子实体多糖（IHFPS）和菌丝体多糖（IHMPS）对小鼠急性酒精肝损伤的保护作用。采用灌胃的方式给予C57BL-6小鼠多糖,连续灌胃3周,最后一次给药4h后,给予乙醇造成小鼠急性酒精肝损伤,通过记录小鼠醉酒、醒酒的时间,测定血清和肝脏相关生理生化指标以及病理切片来评价子实体和菌丝体多糖对急性酒精肝损伤小鼠的作用效果。结果表明,子实体与菌丝体多糖均能够显著延长小鼠的醉酒时间和缩短醒酒时间（P<0.05）,并降低了由酒精引起的肝指数、谷丙转氨酶（ALT）、谷草转氨酶（AST）和丙二醛（MDA）的升高,提高了乙醇脱氢酶（ADH）、过氧化氢酶（CAT）和超氧化物歧化酶（SOD）的活性,病理切片结果进一步证实了子实体多糖与菌丝体多糖可以减轻由酒精引起的细胞损伤,总体来说,子实体多糖比菌丝体多糖对急性酒精损伤小鼠的保护作用更强。该研究表明了粗毛纤孔菌子实体与菌丝体多糖对急性酒精肝损伤小鼠具有一定的保护作用,研究结果丰富了粗毛纤孔菌多糖的药理药效,为其功能食品的开发提供了新思路。     

桦褐孔菌提取物对胃癌MGC-803细胞株的抗增殖与诱导凋亡作用

探讨了桦褐孔菌提取物对胃癌MGC - 80 3细胞株的抗增殖、诱导凋亡作用及对凋亡相关基因表达的影响。MTT比色法结果显示 ,桦褐孔菌提取物在 0 .5～ 16 0 μg/mL范围内 (其IC50 为 4 μg/mL)对胃癌MGC- 80 3细胞株均有抑制作用 ,并表现出浓度依赖性关系 ;凋亡形态学观察结果 ,药物浓度 2 μg/mL ,作用时间 12～ 2 4h后 ,细胞核染色质固缩并凝结成块 ,聚集在核膜周边 ,凋亡小体形成 ;TUNEL法检测结果 ,不同浓度药物均诱导胃癌MGC - 80 3细胞株凋亡 ,细胞凋亡率随药物浓度增加而上升 ,显示明显的量效关系。Ki- 6 7抗原检测结果 ,不同浓度药物均抑制胃癌MGC - 80 3细胞株增殖 ,表现出浓度、时间依赖性关系 ;2μg/mL桦褐孔菌提取物作用胃癌MGC - 80 3细胞株 4 8h之后 ,明显下调Bcl - 2基因蛋白表达。因此 ,通过此项研究可得出 ,桦褐孔菌提取物对胃癌MGC - 80 3细胞株有抗增殖作用和诱导凋亡作用 ,其凋亡的分子生物学机制可能与下调凋亡抑制基因Bcl 2表达有一定关系。     

Inonotus obliquus protects against oxidative stress-induced apoptosis and premature senescence

In this study, we investigated the cytoprotective effects of Inonotus obliquus against oxidative stress-induced apoptosis and premature senescence. Pretreatment with I. obliquus scavenged intracellular ROS and prevented lipid peroxidation in hydrogen peroxide-treated human fibroblasts. As a result, I. obliquus exerted protective effects against hydrogen peroxide-induced apoptosis and premature senescence in human fibroblasts. In addition, I. obliquus suppressed UV-induced morphologic skin changes, such as skin thickening and wrinkle formation, in hairless mice in vivo and increased collagen synthesis through inhibition of MMP-1 and MMP-9 activities in hydrogen peroxide-treated human fibroblasts. Taken together, these results demonstrate that I. obliquus can prevent the aging process by attenuating oxidative stress in a model of stress-induced premature senescence.     

桑黄液体发酵工艺的研究

通过对桑黄液体发酵培养基、培养条件优化实验研究,以获得具有与桑黄子实体相似功效成分的桑黄菌丝体液体发酵工艺。以菌丝体收率为主要考察指标,采用单因子及L9(34)正交实验的方法,对桑黄液体发酵培养基及培养条件进行优化,确定桑黄液体发酵工艺条件。桑黄液体发酵最佳培养基及培养条件:玉米粉2%,葡萄糖3%,酵母膏0.5%,蛋白胨0.5%,KH2PO40.3%,Mg SO4·7H2O 0.15%,VB120μg/100 m L,p H5.5,接种量8%,培养温度28℃,摇床转数180 r/min,培养周期82 h。优化条件下所获得桑黄菌丝体粉为土黄色,菌丝体平均得率为1.67%,菌丝体黄酮含量(0.84%)与桑黄子实体(0.88%)相当,菌丝体多糖含量(5.15%)是子实体(1.71%)的3倍。可见,该桑黄液体发酵工艺具有较大的推广应用价值。     

桦褐孔菌活性物质的提取工艺及体外抗糖尿病活性

对桦褐孔菌活性物质的提取工艺及其体外抗糖尿病活性进行研究。桦褐孔菌子实体用乙醇浸提后,乙醇粗提物用不同有机溶剂萃取,醇提残渣再以热水浸提,用标准曲线法测定活性组分中活性成分的含量,并检测活性物质对羟基自由基(·OH)、超氧阴离子自由基(O2-·)的清除效果以及对关键糖代谢酶α-淀粉酶、α-葡萄糖苷酶的抑制作用。结果表明:4种活性组分(乙酸乙酯相、正丁醇相、水相和粗多糖)对羟基自由基(·OH)和超氧阴离子自由基(O2-·)都有较强的清除作用,其中乙酸乙酯组分的活性最高,乙醇粗提物萃取组分对α-淀粉酶有抑制活性,而粗多糖对α-葡萄糖苷酶有抑制作用;桦褐孔菌具有抗氧化和抗糖尿病活性,其活性与活性物质种类及其含量具有相关性。     

桦纤孔菌有性生殖相关特征及交配型位点分析

对桦纤孔菌菌株MDJCBS88的显微形态、菌丝及担孢子核相进行了观察。采用棉籽壳培养基对担孢子萌发形成的菌株进行栽培试验,筛选出不形成子实体或子实体发育不完整的菌株,将这些菌株在平板上进行了亲和试验,分析桦纤孔菌的有性生殖方式;并基于基因组序列进行交配型基因克隆验证,分析桦纤孔菌的交配型位点结构。显微观察发现,桦纤孔菌菌丝没有锁状联合结构,菌丝细胞无核到多核;子实层担孢子可含0-4个不等的细胞核,不同时期弹射的担孢子含有的细胞核数量不同。桦纤孔菌担孢子萌发率极低,能萌发的担孢子多为早期弹射的担孢子;培养基也影响担孢子的萌发率,与PDA培养基和CYM培养基相比,桦木屑培养基最适合桦纤孔菌担孢子萌发,萌发率为4.55%。从担孢子萌发的96个菌株中获得了2个不结实菌株和9个结实不产孢菌株,占11.5%,这些菌株间亲和试验出现不同的表现特征,包括形成产孢子实体,产生菌丝纽结,相互融合和相互拮抗等现象,认为桦纤孔菌的有性生殖以次级同宗结合为主,并受交配型基因控制。交配型位点克隆测序后分析发现,桦纤孔菌交配型A位点共14 034 bp,含有一个MIP基因和两组HD1和HD2基因;交配型B位点包含3个疑似信息素受体基因和1个信息素前体编码基因。     

桦褐孔菌膜二肽酶在巴斯德毕赤酵母中的分泌表达

本研究利用巴斯德毕赤酵母Pichia pastoris蛋白表达体系表达了药用担子菌桦褐孔菌的一个二肽酶基因。该二肽酶基因编码区全长1814bp,包含6个内含子,编码465个氨基酸。生物信息学分析发现,二肽酶基因编码的蛋白中不含信号肽序列,但在第55–77位氨基酸之间存在一个跨膜结构。将含跨膜结构和去跨膜结构蛋白的cDNA序列分别克隆到酵母分泌型表达载体pPICZαA上,电转化至巴斯德毕赤酵母X-33中,用1%(V/V)甲醇诱导重组菌株表达目标蛋白,采用SDS-PAGE和Western-blot检测表达蛋白。结果显示,巴斯德毕赤酵母可表达含跨膜结构的完整基因,但目标蛋白不能分泌到胞外,存在于破碎细胞的沉淀中,且没有催化活性;而去跨膜结构的蛋白则可分泌表达到胞外,并具有催化活性。Ni-NTA纯化去跨膜结构的桦褐孔菌二肽酶浓度可达0.12mg/mL,并发现其在pH 7.3、反应温度50℃、反应时间2h的条件下,以Gly-Gly为底物时,其比活为433U/mg。同时检测到其对Ile-Leu、Trp-Trp和Phe-Phe具有较高的水解活性。     

桦褐孔菌子实体多糖提取研究

目的:为了获得桦褐孔菌多糖最大量的多糖收率,研究了影响多糖提取的最佳条件.方法:对影响桦褐孔菌胞内水溶性多糖提取效果的6个因素进行了单一因素影响实验,并对多糖提取影响因子的3个因素进行正交试验,对多糖提取工艺参数进行了优化.结果:正交试验确定桦褐孔菌子实体多糖的最佳提取条件是:料水比为1∶40,温度80℃,提取1.5h,多糖收率达2.53％.结论:确立了桦褐孔菌子实体多糖提取工艺,建立了一套简便、高效的桦褐孔菌胞内多糖的提取方法.