Echinacea alkylamides modulate induced immune responses in T-cells

The effects of Echinacea and several of its phytochemical components on NFkappaB expression by Jurkat cells (a human T-cell line) were investigated in vitro. In the absence of stimulation, Echinacea and its components exerted no significant effect on basal NFkappaB expression levels. In the presence of endotoxin (LPS), NFkappaB expression was decreased. However, this decrease was significantly reversed by treatment with cichoric acid, an Echinacea root extract (prepared from both Echinacea angustifolia and Echinacea purpurea) and the alkylamide fraction derived from this combination. For the phorbol myristate acetate stimulation of Jurkat cells, effects on NFkappaB expression were mixed. Depending on the concentration, cichoric acid and a 2,4-diene alkylamide significantly induced NFkappaB levels, whereas a 2-ene alkylamide caused a significant inhibition. In contrast, both the Echinacea and the mixed alkylamide fraction exerted no effect. The alkylamide results indicate that the two basic forms of these compounds present in Echinacea may have opposing effects. These opposing effects demonstrate the importance of a knowledge, not only of the phytochemical make-up of a herbal preparation, but also of the actions of each component and the consequences of differing relative amounts in the preparation being investigated.     

中国水稻白叶枯病菌系染色体DNA的RFLP谱型的初析

用２个ＤＮＡ探针ｐＪＥＬ１０１和ｐＢＡＳａｖｒＸａ１０对７８个水稻白叶枯病菌系进行ＲＦＬＰ分型，以分析其群体结构和遗传多样性。分别鉴定出１６种ＲＦＬＰ标记带的谱型。以彼此的带位相似率达８５％为界，可分为簇。参试菌系的群体遗传多样性为０．７７（用ｐＪＥＬ１０１），和０．８３ＲＦＬＰ谱型分析表明：我国多数病原型为杂合组群。白叶枯病菌系的分子表现型的变异，远远大于致病型，两个探针都能有效分析我国菌系的群     

水稻白叶枯病(Xanthom onas campestris pv.oryzae)抗性遗传研究 Ⅲ.两个成株抗性基因X_a-6与X_a-3的等位性分析

研究了两个品种早生爱国3号和辛尼斯对菲律宾水稻白叶枯病菌4个生理小种、日本小种1和我国菌株的成株抗性遗传和抗性基因的等位关系。这两个抗病品种与感病品种沈农1033杂交所得的 F_1、F_2和 B_1F_1群体的成株抗性反应,表明它们均携有一对显性基因。将早生爱国3号同辛尼斯杂交进行直接等位性测定,并将邳早15和蚌珠芒分别与辛     

9个水稻品种对水稻白叶枯病的抗性遗传研究

研究了８个灿稻抗病品种４号、川植５号、三黄占２号、二九丰、扬稻１号、７５－３４、８３００７、ＮＴ０２和１个粳稻抗病品种湘虎２５对水稻白叶枯菌系Ｐ１、ＨＢ８４－１７或Ｔ１的抗性遗传。这些抗病品种分别与感病品种沈农１０３３或金刚３０杂交，所得的Ｆ１、Ｆ２和Ｂ１Ｆ１群体的抗性反应，表明８个灿稻品种对Ｐ１和ＨＢ８４－１７的全生育期抗性均由一对不完全显性的基因控制，该抗性基因与Ｘａ－４是等位的；粳稻品种湘虎     

Gingerol content of diploid and tetraploid clones of ginger (Zingiber officinale Roscoe)

Ginger (Zingiber officinale Roscoe), a monocotyledonous, sterile cultigen, is widely used as a spice, flavoring agent, and herbal medicine. The pungency of fresh ginger is due to a series of homologous phenolic ketones of which [6]-gingerol is the major one. The gingerols are thermally unstable and can be converted to their corresponding shogaols, which are present in dried ginger. Fresh rhizomes of 17 clones of Australian ginger, including commercial cultivars and experimental tetraploid clones, were assayed by HPLC for gingerols and shogaols. [6]-Gingerol was identified as the major pungent phenolic compound in all samples, while [8]- and [10]-gingerol occurred in lower concentrations. One cultivar known as "Jamaican" contained the highest concentrations of all three gingerols and was the most pungent of the clones analyzed. Gingerols were stable in ethanolic solution over a 5-month period when stored at 4 degrees C. Shogaols were not identified in the extracts prepared from fresh rhizomes at ambient temperature, confirming that these compounds are not native constituents of fresh ginger. In contrast to previous findings, this study did not find significant differences in gingerol concentrations between the tetraploid clones and their parent diploid cultivar.     

Essential oil composition of diploid and tetraploid clones of ginger (Zingiber officinale Roscoe) grown in Australia

Ginger oil, obtained by steam distillation of the rhizome of Zingiber officinale Roscoe, is used in the beverage and fragrance industries. Ginger oil displays considerable compositional diversity, but is typically characterized by a high content of sesquiterpene hydrocarbons, including zingiberene, ar-curcumene, beta-bisabolene, and beta-sesquiphellandrene. Australian ginger oil has a reputation for possessing a particular "lemony" aroma, due to its high content of the isomers neral and geranial, often collectively referred to as citral. Fresh rhizomes of 17 clones of Australian ginger, including commercial cultivars and experimental tetraploid clones, were steam distilled 7 weeks post-harvest, and the resulting oils were analyzed by GC-MS. The essential oils of 16 of the 17 clones, including the tetraploid clones and their parent cultivar, were found to be of substantially similar composition. These oils were characterized by very high citral levels (51-71%) and relatively low levels of the sesquiterpene hydrocarbons typical of ginger oil. The citral levels of most of these oils exceeded those previously reported for ginger oils. The neral-to-geranial ratio was shown to be remarkably constant (0.61 +/- 0.01) across all 17 clones. One clone, the cultivar "Jamaican", yielded oil with a substantially different composition, lower citral content and higher levels of sesquiterpene hydrocarbons. Because this cultivar also contains significantly higher concentrations of pungent gingerols, it possesses unique aroma and flavor characteristics, which should be of commercial interest.     

水稻白叶枯病的抗性遗传

研究了水稻品种IR20、IR22和品系IR152g-680-3、IR1545—284、和RP291—7由Xanthomonas Oryzae(Uyeda and Ishiyama)Dowson引起的白叶枯病抗性基因的遗传方式和等位关系。对抗病亲本和感病品种TN1(台中本地1号)杂交种的F_1、F_2、F_3及正反交回交群体的研究,表明这些品种和选系的抗病性由单基因控制。IR20、IR22和IR1529-680-3的抗性是不完全显性,而IR1545—284和RP291—7是隐性,等位测定明显的指出IR20、IR22和IR1529-680-3有相同的显性抗病基因,这个基因定名为Xa4,IR1545—284和RP291—7有相同的隐性抗病基因,定名为Xa5,Xa4和Xa5相互独立。由Xanthomonas Oryzae(Uyeda and Ishiyama)Doxvson引起的白叶枯病是水稻(Oryzae sative L)最严重的病害之一,损害可能在苗期出现,此时称之为急性萎凋‘Kresck’,或在生长后期发病。损失是由于被侵染的分蘖完全凋萎或叶片的局部到全部枯萎和秕粒数增加。白叶枯病于十九世纪末已在日本报导。大多数种植水稻的亚洲热带和亚热带国家现也有了报导,最近由于农业集约措施,如大量施用N肥、密植高产、感光性不敏感、半矮生性的栽培种等而使这种病害得以增加。为了防治该病,曾试验了许多农药,包括几种抗生菌复合物,虽然有些已在日本应用,但在热带没有一种是高效而经济的。况且细菌对某些药剂能产生抗性。因此,采用抗病的品种似乎是最有效而经济的防治措施。日本早在十九世纪末已注意到栽培种对白叶枯病的抗病性差异,1946年该国推荐种植了第一个抗白叶枯病的品种农林27。1946年以来又培育了几个抗病品种并鉴定了他们的抗病品质。日本鉴别了Xanthomonas Oryzea的三个菌系,几位工作者研究了对这些菌系的抗性遗传。发现品种黄玉、农林27、Kele、和Chinsurah BoroⅡ(钦苏拉、保罗Ⅱ)的抗性来自一个显性基因,坂口报导两个抗病基因相连锁。金杂群品种带有抗病基因Xa1,它传递对白叶枯病菌系Ⅰ群的抗性。伦太艾玛斯(Rantaj.Emas)品种群带有Xa1,Xa2,Xa2传递对菌系Ⅱ群的抗性。Xal和Xa2密切连锁,并位于第11染色体上。另外一群品种是早生爱国群,对日本所有茵系都有抗性。根据乌山和铃木等认为,早生爱国3号群品种的抗性由一个显性基因Xa—W控制,该基因与Xal和Xa2无关,独立一类。但是Xa—W仅在成熟期具有抗性。国际水稻研究所在1963年开始系统研究热带白叶枯病并鉴定了几个抗病品种,这些品种已在国际水稻研究所和其它地方用于育种工作中,并已推荐了几个抗病品种,并已研究了少数品种的抗性遗传。本试验是确定热带育种工作中用做抗沅的品种及品系的抗性遗传方式和等位关系。     

我国水稻抗白叶枯病（Xanthomonas oryzae pv.oryzae）性状遗传研究…

１９９１～１９９４年，通过协作，探索了我国水稻抗白叶枯病性状遗传研究方法标准化的有关问题，内容是：（１）取材和方法，包括选择感病亲本和确定待测抗病材料的基本要求采用菌系的依据，接种鉴定的时间，调查标准等。（２）抗性遗传分析方法，包括配组方式及其群体样本容量，遗传分析内容，以及新基因的鉴定，定位及命名等方法和步骤。笔者在本文提出了一个初步的设想，拟与本领域的科学家们进行研讨，便于进一步完善，这将对我     

水稻白叶枯病抗性基因鉴定进展及其利用

 1982~1987年，日本热带农业研究中心（TARC）和国际水稻研究所（IRRI）合作采取统一研究方案，创建了国际水稻白叶枯病抗性鉴别系统。统一了命名，删去了重复（包括与Xa3相同的Xa4b、Xa6和xa9）。截至2005年6月，经国际注册确认和期刊报道的水稻白叶枯病抗性基因共30个，其中 Xa22(t)、Xa26(t)、xa26(t)、Xa27(t)、xa28(t)、Xa29(t)和3个Xa25(t)为暂定名基因，有待订正。在30个基因中，21个为显性基因（Xa），9个为隐性基因（xa）；13个表现全生育期抗性，15个为成株期抗性，Xa21和Xa25(t) (O. minuta)两个基因在分蘖后期表达抗性。已被定位的抗性基因有17个，即第11染色体上有7个，Xa3、Xa4、Xa10、Xa21、Xa22(t)、Xa23和Xa26；第4染色体上有4个，Xa1、Xa2、Xa12和Xa14;第5染色体上有2个，xa5和xa13；第6染色体上有Xa7和Xa27；第12染色上有Xa25(t)；第1染色体上有Xa29（t）。包括Xa1、xa5、Xa21、Xa26五个基因已被克隆。并讨论了合理利用抗性基因等问题。