A new model for chemotactic signal transduction in Dictyostelium discoideum

Dictyostelium discoideum amoebae were employed to study the refractoriness and adaptation of the rapid (5sec) accumulation of actin in their Triton-insoluble cytoskeletons following stimulation with specific chemoattractants. Amoebae became refractory within 10sec for this response but no adaptation occurred during this period. Amoebae desensitized for one attractant were not desensitized for another and responses to stimulation with a mixture of attractants were approximately additive. The characteristics of these processes are compared to published studies of adaptation in other chemoattractant-induced responses and a new model for the chemotactic signal transduction pathway is formulated. We conclude that intracellular cGMP accumulation may be on a separate branch of the pathway from the actin response.     

西藏细柄茅属（禾本科）一新种

大穗细柄茅PtilagrostismacrospiculaL.B.Cai,sp.nov.Fig.1.Typus:Xizang(西藏),YadongXian(亚东),NearChuntang(春塘),inpratisclivorum,at4200melevation,Sept.14,1974,Qinghai-XizangExped.(青藏队)74-2496(HNWP).HaecspeciesP.concinnae(Hook.f.)Roshev.proxima,aquadiffertligulis2.5～3.5mmlongis,spiculis8.0～12.5mmlongis(aristisexclusis),duabusglumisnonaequalibus,lemmatibus5.5～8.0mmlongis,paleislemmatibusevidenterbrev-ioribus,antheris1.8～2.5mmlongis.Herbaeperennes,radicibusfibrosistenuibus.Culmi…     

平菇与香菇属间原生质体融合的研究

通过分离和出菇试验,获得了纯化的平菇(Pleurotus sapidus)和香菇(Lentinus edodes)单孢系。用溶壁酶去细胞壁制备成原生质体。以PEG为融合诱导剂,诱导两者原生质体融合。1988年获得了可以出菇的融合子。这些融合子形成的子实体,从形态、生长习性和菌伞的颜色特征上都与双亲有明显的差异。大部分氨基酸含量介于双亲之间。同功酶分析也显示出融合子呈现与双亲不同的酶带。融合子出现的上述新性状,可能是平菇与香菇的原生质体基因重组的结果。     

Ferroelectricity in the arterial wall: A new physical component of atherosclerosis

The appearance of two electric potentials in the aorta is explained by the blood pulse and the remote steps of atherosclerosis are elucidated from the physical point of view. When the first C-C-2W is deposited in the intimamedia, the primary cause of their retention is the stress-induced polarization of the membrane. C-C-2W possesses a permanent dipole moment which may be reversed by the field produced by the radial expansion/contraction of the arteries.The initial C-C-2W increases the polarization of the aorta walls, favoring accumulation of more oriented material on top of the first. C-C-2W is also ferroelectric and constitutes a polar continuum with the membranes. By the time fatty streaks appear, the entire aorta wall is ferroelectric and energy has been stored in the walls under the form of residual polarization. This storage gradually destroys the wall, leading to aneurism. The biological significance of the new theory is summarized in Table 2.     

肉桂酸和邻苯二甲酸对沙芥属植物幼苗光合特性的影响

为探讨肉桂酸和邻苯二甲酸对沙芥属植物光合特性的影响,以沙芥和斧翅沙芥幼苗为试验材料,研究 0、0.01、0.1、1和10 mmol·L-1肉桂酸和邻苯二甲酸处理下其生长、叶绿素含量、叶绿素荧光参数和气体交换参数的变化。结果表明：（1）肉桂酸、邻苯二甲酸对沙芥幼苗生长均表现为低浓度促进高浓度抑制,而对斧翅沙芥生长则表现为抑制作用,肉桂酸、邻苯二甲酸浓度为10 mmol·L-1时对沙芥属植物的生长抑制作用最显著。（2）不同浓度肉桂酸和邻苯二甲酸处理后沙芥与斧翅沙芥的叶绿素a（Chl a）、叶绿素b（Chl b）、叶绿素总量(Chl.a+b)均出现不同程度的下降（3）沙芥和斧翅沙芥叶片净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）在肉桂酸和邻苯二甲酸浓度为10 mmol·L-1显著低于对照,胞间 CO2浓度（Ci）无显著变化,其光合速率降低的主要原因是由非气孔因素所致。（4）沙芥和斧翅沙芥的最大光化学效率（Fv/Fm）、实际光化学效率（ФPSII）和光化学猝灭系数（qP）均在肉桂酸和邻苯二甲酸浓度为10 mmol·L-1显著低于对照,而非光化学荧光猝灭系数( NPQ ) 则显著高于对照。研究表明,高浓度邻苯二甲酸和肉桂酸抑制沙芥和斧翅沙芥幼苗的光合作用,降低其光合速率,导致沙芥和斧翅沙芥叶片的PSII反应中心活性和开放程度受损,进而影响沙芥和斧翅沙芥的生长。另外肉桂酸和邻苯二甲酸对沙芥属植物光合特性的影响表现出差异,这可能是由于植物类型和胁迫类型不同而表现出不同的变化趋势。     

A Taxometric Analysis of Characters of Polygonum lapathifolium L.

Polygonum lapathifolium L. is a morphologically variable and taxonomically complicated group. The height of plants and the degree of nodal expansion greatly vary in different habitats. In this work field observation and mass collection in different habitats of this species were made. By means of biometric techniques, principal component analysis, discriminant analysis, scatter diagram and histogram, supplemented by transplantation experiment, it is revealed that the height of plants and the degree of nodal expansion of P. lapathifolium are evidently affected by environmental conditions, and these two variables are not correlated with, but independent from, each other. The results also show that the indumentum on the lower leaf surface is not constant. Therefore all the characters are not reliable diagnostic ones and any taxonomic treatment based on these characters is not reasonable. In this paper, P. nodosum Pers. is reduced as a synonym of P. lapathifolium L. and P.lapathifolium var. salicifolium Sibth. is also eliminated.     

中国东北地区地卷属地衣的研究

本文作者根据前人的文献资料,对中国科学院林业土壤研究所1950年以来在东北地区所采集的1200余号地卷属地衣植物标本进行整理、研究,共报道23个种,其中8个种为东北地区新分布。本文包括属的特征、分种检索表、种的文献考证、生境、产地以及国内外的地理分布。     

蜈蚣草耐铅、铜、锌毒性和修复能力的研究

重金属复合污染是主要土壤污染类型之一。为了探明蜈蚣草修复土壤重金属复合污染的能力,土培试验研究了分别添加不同浓度铅、铜、锌条件下蜈蚣草生物量变化,结果表明,不同浓度铅和较低浓度锌处理下蜈蚣草生物量呈显著性地增加,土壤Pb、Zn添加浓度分别为1750mg／kg和1350mg／kg,蜈蚣草生物量最大。说明蜈蚣草有极强的耐Pb、Zn毒性能力,能在较高有效态Pb或Zn污染土壤上正常生长。蜈蚣草具有一定的耐Cu毒性能力,在Cu耐性方面,蜈蚣草可能存在生态型的差异。以上结果说明,利用蜈蚣草修复萃取Pb—As,Zn—As,Cu-As等复合污染土壤上As有重要的意义。     

Sesquiterpenoids of fourteen Plagiochila species

The distribution of ent-2,3-secoaromadendrane-, ent-aromadendrane-, ent-bicyclogermacrane- and ent-maaliane-type sesquiterpenoids in fourteen Plagiochila species is described. These sesquiterpenes are the significant chemosystematic markers of Plagiochila. The intense pungent substance of some Plagiochila species is due to an ent-2,3-secoaromadendrane-type sesquiterpene hemiacetal, plagiochiline A.     

Evolutionary basis and ecological role of toxic microbial secondary metabolites

This presentation develops a theory of the evolutionary origin and ecological implications of toxic microbial secondary metabolites. The theory is based on a model system that outlines cause—effect associations between pertinent biotypes in the aflatoxin contamination of developing maize kernels. The model suggests that the aflatoxin-producing fungi are natural digestive tract inhabitants of a number of insect species that feed on developing kernels. During feeding, the insect larvae introduce fungal propagules and provide infection sites on damaged kernels. The fungal association with insects exhibits extraordinary variability, ranging from symbiotic to pathogenic. Elaboration of aflatoxin by the fungus facilitates the pathogenic process in host insects. The theory contends that genetic information for secondary microbial metabolites evolved during ecosystem disequilibria. During periods of ecological stability, mechanisms evolved for repression of toxic secondary metabolite biosynthesis. The theory broadly suggests that contemporary agricultural activities presents the requisite milieu for production or toxic microbial secondary metabolites.     

西洋参和人参的可溶蛋白电泳鉴别

西洋参 (ＰａｎａｘｑｕｉｎｑｕｅｌｉｕｍＬ .)又称花旗参、美国人参 ,原产美国和加拿大 ,在我国的保健品市场占有很大的销售份额 ,西洋参在我国虽已引种成功 ,但主要还靠国外进口 ,价格昂贵 ,因此很多保健品利用价格相对低廉的人参 (Ｐ .ｇｉｎｇｓｅｎｇＣ .Ａ .Ｍｅｙ)伪充西洋参。近年来国内有许多学者利用多种手段对西洋参和人参进行鉴别 ,但由于西洋参和人参的性状、成分极其相似 ,现有的方法难以将二者完全区分开来 ,因此 ,有必要寻求新的快速灵敏的鉴别方法。蛋白质电泳方法早已广泛应用于医学、农学和微生物学 ,目前也逐步运用于…     

青海黄精属一新种

发表了黄精属一新种,即青海黄精Polygonatum qinghaiense Z．L．Wu et Y．C．Yang。本种近似独花黄精P．hookeri Baker．但叶长圆形或狭椭圆形,花淡黄色或白色,裂片具3脉,与筒部几等长．雄蕊着生于花被近喉部等是其主要区别。     

拟盘多毛孢属真菌的新种*

报导拟盘多毛孢属真菌的8个新种。这8个新种是:近似状拟盘多毛孢Pestalotiopsis affinis、山姜拟盘多毛孢P. alpiniae、见血封喉拟盘多毛孢P. antiaris、五桠果拟盘多毛孢P. dilleniae、广西拟盘多毛孢P. kuwangsiensis、莲拟盘多毛孢P. nelumbinis、木荷拟盘多毛孢P. schimae、和神秘果拟盘多毛孢P. synsepali。新种的模式标本保存在广西大学植保系标本室。     

松属植物种子油脂肪酸的分布及化学分类探讨

用气相色谱-质谱(GC-MS)方法分析了6种双维管束松亚属树种:赤松(Pinus densiflora Sieb.etZucc.)、黑松(P.thambergii Parl.)、油松(P.tabulaeformis Carr.)、巴山松(P.henryi Mast.)、黄山松(P.taiwanensis Hayata)、马尾松(P.massoniana Lamb.)和2种单维管束松亚属树种:白皮松(P.bungeanaZucc.)及红松(P.koraiensis Sieb.et Zucc.)的种子油脂肪酸成分。结果表明这8种松属植物的种子油脂肪酸成分有相似的分布情况:最主要成分都是亚油酸C_(18:2(9,12));都同时含有3种Δ~5的不饱和脂肪酸:C_(18:2(5,9)),C_(18:3(5,9,12))和C_(20:3(5,11,14))。这两个特征可以作为松属(Pinus L.)的化学分类证据。结果还表明同一属内各种间的种子油脂肪酸成分无明显差别。     

Discrimination Amongst Leishmania by Polymerase Chain Reaction and Hybridization with Small Subunit Ribosomal DNA Derived Oligonucleotides

ABSTRACT. A method for discriminating among Leishmania is described, based upon small subunit ribosomal DNA sequence differences. The method was to amplify the entire 2.2 kb small subunit rDNA by polymerase chain reaction using conserved primers specific for the 5' and 3' termini of the small subunit ribosomal RNA, and then hybridize the product dotted onto nylon membranes with labeled oligonucleotides. The design of the hybridization probes was based upon complete small subunit rDNA sequences from L. amazonensis, L. major and L. guyanensis and partial sequences of L. mexicana, L. braziliensis, L. tropica and L. chagasi. A high degree of sequence similarity (> 99%) among species was found. However, sufficient sequence divergence occurred to permit the design of internal oligonucleotide probes specific for species complexes. This procedure successfully discriminated amongst a wide range of Leishmania isolates. The method detected as few as 10 cultured organisms and detected parasites in tissue samples from experimentally infected animals. Non-radioactive labeling showed the same specificity and sensitivity as radioactive probes.     

东北地区乳菇属的初步研究

本文报道了东北地区乳菇属(Lactarius)的29种,其中包括新种2个,长白乳菇(L.chanbainensis Y.Wang et Xie sp.nov.)温泉乳菇(L.wenquanensis Y.Wang et Xie sp.nov.);国内新记录种5个:茶绿乳菇[L.necator(Pers.ex Fr.)Farst.],条纹乳菇[L.oculatus(Peck)Burl.],变红乳菇[L.acris(Bolt.ex Fr.)Gray],复生乳菇(L.repraesentaneus Britz.)和点柄乳菇(L.maculatus Burl.)。新种有汉文和拉丁文描述以及形态、显微构造图;国内新记录种有汉文描述。