Detection, characterisation and transmission by Macrosteles leafhoppers of watercress yellows phytoplasma in Hawaii

A new yellows disease of watercress (Nasturtium officinale) in Hawaii has symptoms of reduced leaf size, leaf yellowing and crinkling, and occasionally witches’ brooms. This disease is found on all watercress farms on Oahu but has not yet been found on other Hawaiian islands. Watercress plants were tested for phytoplasma infection by polymerase chain reaction assays using phytoplasma‐specific primers. Amplicons of the expected sizes were produced from all symptomatic plants but not from healthy plants raised from seed. Phylogenetic analysis of the 16S rRNA gene indicated that watercress yellows was caused by a phytoplasma in the aster yellows group, with sequence similarity to onion yellows from Japan. Six weed species collected from the vicinity of affected watercress farms, Amaranth sp., Eclipta prostrata, Emilia sonchifolia, Plantago major, Myriophyllum aquaticum and Sonchus oleraceus, were also determined to be hosts of this phytoplasma. Leafhoppers, identified as Macrosteles sp. (Hemiptera, Cicadellidae), collected from symptomatic watercress transmitted this phytoplasma to watercress, plantain and lettuce (Lactuca sativa) in greenhouse experiments.     

铁皮石斛愈伤组织诱导研究

研究不同培养基和光照条件对铁皮石斛愈伤组织诱导的影响。结果表明,外植体直接接种于培养基上,最适宜培养条件是MS 5.92 g·L^-1＋2,4-D 5 mg·L^-1＋IAA 1.5 mg·L^-1＋KT 0.62 mg·L^-1＋蔗糖37.5 g·L^-1＋琼脂0.8% (pH 5.9～6.0),暗培养15 d后再光培养;外植体捣碎后平铺于培养基上,最适宜培养条件是MS 4.74 g·L^-1＋2,4-D 1 mg·L^-1＋IAA 1.5 mg·L^-1＋KT 0.25 mg·L^-1＋蔗糖30 g·L^-1＋琼脂0.8% (pH 5.9～6.0),25 ℃持续光培养。     

Survival of dried eukaryotes (anhydrobiotes) after exposure to very high temperatures

Organisms that tolerate essentially complete dehydration are said to be in anhydrobiosis, and can be referred to as anhydrobiotes. Those organisms are of great ecological and medical importance, but also provide models for the study of a variety of biological phenomena. We examined the tolerance of selected eukaryotic anhydrobiotes to high temperatures using slow (∼4 °C min⁻¹) and rapid (∼100 °C min⁻¹) heating to 110, 120, 130, and 140 °C. Test organisms were then either returned to storage temperatures close to 22 °C (preheating), or held at those high temperatures for an additional 10 min. Some anhydrobiotes survived slow heating to 130 °C, whereas rapid heating led to a dramatic reduction in survival. None of these organisms encounter anywhere near these high temperatures in nature, so tolerance is not an obvious result of adaptation to current or recent conditions. We speculate that tolerance could have been achieved during the much earlier evolution of these organisms, and has been retained up to the present.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 15–22.     

杉科的细胞分类学和系统演化研究

根据杉科的核型资料,本文(1)提出“1B”可能是一个新的高等植物核型类型;(2)讨论了各属的有关分类学问题及相互亲缘关系,它们的进化顺序可能是柳杉属、水松属、落羽杉属、水杉属、巨杉属、红杉属、杉木属(密叶杉属与之近缘)、台湾杉属;(3)支持金松属分立成金松科,它可能比杉科各属原始;(4)红杉(AAAABB)的亲本可能是二个古代种水杉”和“巨杉”,它们的直接后裔或留下的近缘是水杉和巨杉;(5)杉科存在A和L两条进化路线,前者包括柳杉属、水松属、落羽杉属、台湾杉属,后者包括水杉属、巨杉属、红杉属、杉木属(密叶杉属);(6)提出一个杉科新系统(包括一个新亚科)：I．柳杉亚科(柳杉属),II．落羽杉亚科(水松属、落羽杉属),III．红杉亚科(冰杉属、巨杉属、红杉属),Ⅳ.杉木亚科(杉木属、密叶杉属),V．台湾杉亚科,新亚科(台湾杉属)。本文还对前人的杉科系统作了讨论。     

铁皮石斛多糖对高脂饮食小鼠肠黏膜结构及菌群的影响

为考察铁皮石斛多糖对高脂饮食小鼠肠黏膜屏障的影响,采用水提醇沉法提取铁皮石斛多糖,联合高脂饲料给予小鼠8周后观察肠黏膜结构及肠黏膜菌群的变化。结果显示高脂饮食显著破坏了肠黏膜结构,表现为肠黏膜萎缩,上皮细胞脱落并伴有炎性渗出,Corynebacterium_1及Staphylococcus等与感染及炎症相关的菌属大量增殖。铁皮石斛多糖对肠黏膜结构有较好的保护作用,并可减少Corynebacterium_1的丰度,同时提高肠黏膜共生菌Candidatus_Arthromitus的丰度,促进了Muribaculaceae、Bacteroides、Lachnospiraceae_NK4A136_group等碳水化合物代谢、短链脂肪酸产生相关菌的增殖。研究表明铁皮石斛多糖对肠黏膜屏障的保护作用或与其维持肠黏膜结构完整,调节肠黏膜菌群组成及促进碳水化合物代谢,生成短链脂肪酸有关。     

铁皮石斛无菌播种产业化繁育技术研究

以铁皮石斛的蒴果为外植体,采用种子→原球茎→完整植株→移栽的途径快速成苗进行工厂化生产,对各阶段培养基进行筛选,以及其他一些影响因子进行比较研究。结果表明:人工授粉后生长60～180d的铁皮石斛种子在离体条件下均能萌发,其中授粉150～180d种子的萌发效果最好,萌发率为87.2%～94.4%,适宜的萌发培养基为MS+6-BA 1.0mg/L+NAA 0.1mg/L+马铃薯汁200g/L+AC 1.0g/L;原球茎增殖的最佳培养基为MS+6-BA 1.5mg/L+NAA 0.1mg/L+香蕉汁100g/L+AC 1.0g/L,繁殖系数约为20倍/50d;原球茎在MS+6-BA 1.0mg/L+NAA 0.1mg/L+马铃薯汁200g/L+AC 1.0g/L培养基上进行分化培养,分化的同时还能进行一定的增殖;将已分化的芽苗转接到壮苗培养MS+6-BA 0.5mg/L+NAA 0.2mg/L+香蕉汁100g/L+AC 1.0g/L上培养1代后,转接到生根培养基1/2MS+NAA 0.8mg/L+无机盐A 0.2～0.5mg/L+香蕉汁100g/L+AC 1.0g/L上,培养50～70d后,生根率100%,无机盐A可以有效地控制愈伤或原球茎的形成,明显提高生根苗的数量和质量。在桂林地区,生根苗以3～5月和9～10为最佳移栽期,以通过高温处理并堆沤腐熟的松树皮为基质,移栽成活率可达90%。     

铁皮石斛内生真菌的分离及其挥发性成分分析

铁皮石斛(Dendrobium officinale)是我国重要的濒危中药材,其药用价值和经济价值很高。以铁皮石斛为研究对象,采用组织块法,从铁皮石斛根、茎和叶中分离获得22株内生真菌。采用固相微萃取固定吸附(SPME),结合气相质谱(GCMS)解吸附分析技术对其中具有产香特性的3株内生真菌KLBMPD001、KLBMPD004和LBMPD009的挥发性成分进行分析。结果显示,这3株内生真菌均含有较高比例的棕榈酸,分别为37.94%、24.15%和48.55%,其中菌株KLBMPD001和KLBMPD009含有一定比例的硬脂酸,分别为12.64%和37.37%,只有菌株KLBMPD004含有8.74%的酞酸二丁酯。     

超微铁皮石斛对脾虚便秘小鼠肠道乳酸杆菌多样性的影响

【目的】探讨超微铁皮石斛对脾虚便秘小鼠肠道乳酸杆菌多样性的影响,为疗效提供依据。【方法】制备小鼠脾虚便秘模型,灌胃铁皮石斛传统汤剂、超微50%量汤剂治疗,采集肠道内容物提取肠道微生物宏基因组DNA,用乳酸杆菌特异引物PCR后进行ARDRA分析。【结果】结果显示,正常组、铁皮石斛传统汤剂组和超微50%量汤剂组的OTUs、Shannon指数和Brillouin指数相同,且均大于模型组;铁皮石斛超微50%量汤剂组与正常组乳酸杆菌群落结构的相似性系数最大,为0.333 3,其次是模型组为0.181 8,传统汤剂组最小,为0.166 7;聚类分析和主成分分析结果显示,小鼠肠道乳酸杆菌多样性受脾虚便秘造模影响,发生改变,铁皮石斛两种汤剂通过不同的途径对其进行调控作用。【结论】铁皮石斛对脾虚便秘小鼠肠道乳酸杆菌多样性的调整作用明显,且超微50%量汤剂组小鼠肠道乳酸杆菌多样性更接近正常组,疗效更优。     

Selected cultural and environmental parameters influence disease severity of dandelion caused by the potential bioherbicidal fungi, Phoma herbarum and Phoma exigua

Selected cultural and environmental variables were investigated for their influence on the efficacy of Phoma herbarum and Phoma exigua to cause disease on dandelion (Taraxacum officinale) under growth room conditions. In both species, mycelial fragments caused significantly greater disease severity on dandelion than spore suspensions. Mycelial age was not an important factor in disease severity caused by P. herbarum, with all cultures causing high disease ratings. However, younger cultures of P. exigua caused the greatest disease severity on dandelion, but significantly less than that caused by P. herbarum. The initial pH of the growth medium (potato dextrose broth) did not affect disease severity caused by either Phoma species. Increasing concentrations of mycelia of P. herbarum were applied to dandelions that were then exposed to various leaf wetness durations. Disease severity increased with increasing leaf wetness duration. For dandelions exposed to no leaf wetness duration, the greater the mycelial concentration, the greater the disease rating. However, for dandelions exposed to all leaf wetness durations, all concentrations of mycelia caused similar disease ratings. As P. herbarum caused high disease ratings on dandelion, it therefore warrants further investigation as a potential bioherbicide for the control of this weed.