20株生孢囊放线菌形态及化学分类的研究

经形态、细胞壁化学组分、甲基萘醌组分及磷酸类脂等项分类指征的分析,对从云南地区分离到的20株在气生菌丝上可形成孢囊的放线菌进行了分类鉴定。结果表明,在形态及细胞壁、甲基萘醌组分三个方面均与链孢囊菌属(Streptosporangium)相一致,但在磷酸类脂组分上有4株菌与此属存在一定的差异。     

锥状施克里普藻孢囊的多种形态特征

休眠孢囊是某些甲藻生活史的重要阶段, 它被认为是甲藻赤潮爆发的种源。通过观察我国沿海海域采集的锥状施克里普藻(Scrippsiella trochoidea (Stein) Loebl ich)休眠孢囊的类型以及形态特征, 并将实验条件下形成的休眠孢囊与海区沉积物中休眠孢囊的形态特征进行比较, 结果表明, 锥状施克里普藻细胞在20°C、12小时光照/12小时黑暗、f/2培养基和f/2-N培养基中分别培养至第14天和第8天, 可以观察到休眠孢囊的产生。培养30天后, 培养液中有大量休眠孢囊, 将藻液避光保存90天后, 观察到培养基中有4种类型的休眠孢囊产生: (1)球形到椭球形(长25-39 μm), 钙质外壁, 稀疏或密被钙质附属物(长1-4 μm); (2)球形(直径为29-35 μm), 钙质外壁, 附属物非钙质(长0.5-1.5 μm); (3) 球形到椭球形(长29-35 μm), 钙质, 表面光滑, 无附属物; (4) 球形(直径24-35 μm ), 有机外壁, 无附属物。第1种类型的孢囊最为常见, 分别占到2种培养条件下所得全部孢囊的77.70%和95.18%。从沉积物中所得的孢囊多属于第1种类型。分析了实验条件下形成不同类型休眠孢囊的原因和比例, 同时探讨了海区沉积物中形成多种孢囊形态特征的原因, 为锥状施克里普藻孢囊的生态研究提供了依据。     

锥状施克里普藻孢囊的多种形态特征

休眠孢囊是某些甲藻生活史的重要阶段,它被认为是甲藻赤潮爆发的种源。通过观察我国沿海海域采集的锥状施克里普藻（Scrippsiella trochoidea（Stein）Loeblich）休眠孢囊的类型以及形态特征,并将实验条件下形成的休眠孢囊与海区沉积物中休眠孢囊的形态特征进行比较,结果表明,锥状施克里普藻细胞在20°C、12小时光照/12小时黑暗、f/2培养基和f/2-N培养基中分别培养至第14天和第8天,可以观察到休眠孢囊的产生。培养30天后,培养液中有大量休眠孢囊,将藻液避光保存90天后,观察到培养基中有4种类型的休眠孢囊产生：（1）球形到椭球形（长25-39μm）,钙质外壁,稀疏或密被钙质附属物（长1-4μm）;（2）球形（直径为29-35μm）,钙质外壁,附属物非钙质（长0.5-1.5μm）;（3）球形到椭球形（长29-35μm）,钙质,表面光滑,无附属物;（4）球形（直径24-35μm）,有机外壁,无附属物。第1种类型的孢囊最为常见,分别占到2种培养条件下所得全部孢囊的77.70%和95.18%。从沉积物中所得的孢囊多属于第1种类型。分析了实验条件下形成不同类型休眠孢囊的原因和比例,同时探讨了海区沉积物中形成多种孢囊形态特征的原因,为锥状施克里普藻孢囊的生态研究提供了依据。     

固氮菌的孢囊

在特定条件下,自生固氮菌（Ａｚｔ）ｔｏｂａｃｌｅｒｓｐ．）的营养细胞会转变成一卵圆形或球形的休眠体,称为抱囊（Ｃｙｓｔ）。‘ｌ抱羹的形态结构固氮菌的抱囊为球形或卵圆形,大小为１．ＳＸ２．ｏｐｍ［‘］,体积大约为营养细胞的一半,其结构在光学显微镜下至少可分为３部分：中心体（ｃｅｎｔａｌｂｏｄｙ）、内壁层（ｉｎｈｎｅ）和外壁层（ｅｘｉｎｅ）。Ｐｏｐｅ等ｌ’］用钉红染色可见外壁层外还有荚膜．抱囊的中心体是收缩的细胞质部,往往内含数个折射的颗粒,为聚卜羟基丁酸盐（ＰＨＢ）颗粒。紧绕着中心体的为细胞质膜,…     

日本仙人掌中仙人掌孢囊线虫形态和分子鉴定

【背景】近年来,种苗等植物通过邮寄包裹进入我国的数量越来越多,有害生物随之入侵的风险与日俱增。深圳口岸曾多次从入境包裹中截获孢囊线虫、根结线虫等。【方法】2015年10月12日,深圳口岸在对日本邮寄来的仙人掌进行检疫时,从其根部发现了一种孢囊线虫。对该线虫进行分离,结合形态学和28S r DNA序列扩增并测序的方法,对截获的线虫进行鉴定。【结果】分离到了一种孢囊线虫,其形态特征与仙人掌孢囊线虫基本吻合,28S r DNA序列与Gen Bank数据库中登录号为DQ328702的德国群体的同源性高达99%。因此,判定截获的线虫为仙人掌孢囊线虫。【结论与意义】入境包裹检疫需要引起口岸检疫部门的高度重视。采用形态学和分子生物学相结合的方法对植物寄生线虫进行鉴定,可以得到更加准确的结果。     

无定形孢囊菌属中的一个新种

从我国云南省的土壤中分离出一株放线菌(B133号菌株),该菌株无气丝,基丝侧枝顶端或孢囊梗上形成裂叶状、掌状或棒状的孢囊,细胞壁组扮Ⅱ型。根据这些特征,此菌株应属于游动放线菌科中的无定形孢囊菌属。它与该属的已知种比较均有显著差别,因此认为是一新种,定名为栗色无定形孢囊菌(Amorphosporangium castaneum n. sp.)。     

肉色链孢囊菌和桔橙指孢囊菌发酵液中化学成分的研究

采用硅胶柱色谱、凝胶柱色谱等分离手段,利用波谱分析方法,分别对放线菌肉色链孢囊菌(Streptospor-angium carneum)与桔橙指孢囊菌(Dactylosporangium aurantiacum)发酵液中的化合物进行分离鉴定。从肉色链孢囊菌发酵液中分离得到3个化合物,分别鉴定为腺嘌呤核苷(1),2′-脱氧腺苷(2),5,7,4′-三羟基异黄酮(3)。从桔橙指孢囊菌发酵液中也分离得到3个化合物,分别鉴定为腺嘌呤核苷(1),5,7,4′-三羟基异黄酮(3),2′-脱氧尿嘧啶核苷(4)。     

生孢囊放线菌及其它属菌的甲基萘醌

用高压液相层析对31个属90株生孢囊放线菌及其它属菌的甲基萘醌进行了测定。其结果表明：游动放线菌属．小瓶菌属和小单孢菌属的甲基萘醌为MK-9(H4)MK-10(H4),无定形孢囊菌属和游动单孢菌属的甲基萘醌为MK-9(H4),指孢囊菌属的甲基萘醌为MK-9(H8)MK-9(H4),链孢囊菌属的甲基萘醌为MK-9(H4)或MK-9(H6),螺孢菌属的甲基萘醌为MK-9(H6)MK-9(H4),游动双孢菌属的甲基萘醌为MK-9(H2)MK-9(H4)。不同放线菌属的甲基萘醌组份是较稳定的,可作为属的分类特征之一。建议用甲基萘醌与形态和细胞壁化学组份相结合区分放线菌中的不同属。     

氮磷限制对锥状斯氏藻孢囊形成的作用

在实验室研究了锥状斯氏藻(Scrippsiellatrochoidea)在N、P单因子营养限制(N:500μg.L-1,P:74～0.74μg.L-1和P:74μg.L-1,N:500～5μg.L-1)条件下的生长和孢囊形成。结果显示N、P限制不利于锥状斯氏藻的快速生长,其中低P对细胞生长的限制作用更显著。其孢囊形成率在15～99%之间,中度N限制能促进孢囊的形成,形成率几乎可达100%。孢囊一般在对数生长期结束、细胞数量达到最大值时开始形成。但由于接种后营养盐浓度的急剧降低,营养极度限制组孢囊可在接种后第1d就开始形成。结果显示稳定生长期孢囊的大量形成大大降低了锥状斯氏藻营养细胞数量,能在一定程度上促进其赤潮的消亡。     

2004年春季长江口海域甲藻孢囊的分布研究

于2004年4月初,采集长江口(E122°～123°30',N29°～32°)10个站点0～15cm底泥样品,研究甲藻孢囊在这10个站点的水平和垂直分布情况。在30个样品中共鉴定出6大类24种甲藻孢囊。孢囊组成以异养型原多甲藻类孢囊为主,有13种,平均密度为157cysts·g^-1DW,为调查海域的最优势种群。两种产麻痹性贝类毒素(Paralytic shellfish poisoning,PSP)的孢囊,塔玛亚历山大藻和链状裸甲藻,在海区分布广泛但数量较低。10个站点甲藻孢囊的种类数在11～18种之间,平均密度为189～846cysts·g^-1DW,在远离河口的D6站点有一个明显的最高峰,位于最北部的D1站点孢囊密度最低。与其它海湾相比,属于孢囊密度较低的海区。Shannon-Weaver生物多样性指数(H')变化范围在2.57～3.27之间。甲藻孢囊的密度分布与生物多样性相关系数r=-0.72。3个不同深度的甲藻孢囊密度分别为351cysts·g^-1DW、412cysts·g^-1DW、432cysts·g^-1DW;生物多样性指数分别为3.22、2.95、2.98。     

中国金藻新记录种——中型鱼鳞藻

该文报道了一株采自黑龙江省伊春市的鱼鳞藻,使用透射电子显微镜对其鳞片和刺毛等主要鉴定特征的亚显微结构进行观察,将分离纯化后的藻株提取DNA并扩增目的基因SSU rDNA及LSU rDNA,根据基因序列联合构建系统发育树,结合形态学特征与分子生物学方法,鉴定该鱼鳞藻为中型鱼鳞藻(Mallomonas intermedia),该种也是首次在中国和亚洲发现。同时讨论了该种与鱼鳞藻属同一系列其他组物种的系统关系以及该种在全球的分布与传播。该研究为中型鱼鳞藻的地理分布、金藻和其他微藻的传播扩散提供了新的资料。     

The phylogenetic placement of Ostropales within Lecanoromycetes (Ascomycota) revisited

Results of molecular studies regarding the phylogenetic placement of the order Ostropales and related taxa within Lecanoromycetes were thus far inconclusive. Some analyses placed the order as sister to the rest of Lecanoromycetes, while others inferred a position nested within Lecanoromycetes. We assembled a data set of 101 species including sequences from nuLSU rDNA, mtSSU rDNA, and the nuclear protein-coding RPB1 for each species to examine the cause of incongruencies in previously published phylogenies. MP, minimum evolution, and Bayesian analyses were performed using the combined three-region data set and the single-gene data sets. The position of Ostropales nested in Lecanoromycetes is confirmed in all single-gene and concatenated analyses, and a placement as sister to the rest of Lecanoromycetes is significantly rejected using two independent methods of alternative topology testing. Acarosporales and related taxa (Acarosporaceae group) are basal in Lecanoromycetes. However, if the these basal taxa are excluded from the analyses, Ostropales appear to be sister to the rest of Lecanoromycetes, suggesting different ingroup rooting as the cause for deviating topologies in previously published phylogenies.     

Genome Analysis inNeurospora crassa;Cloning of Four Lociarginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) and Associated Chromosome Walking

We have cloned fourNeurospora crassagenes by complementation analysis. Cloned genes include thearginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) loci. Chromosome walks were initiated in ordered cosmid libraries from the cloned loci. A total of about 700 kb of theNeurosporagenome is covered in these walks.     

The phylogenetic placement of the Leucogastrales, including Mycolevis siccigleba (Cribbeaceae), in the Albatrellaceae using morphological and molecular data

The morphology of many hypogeous fungi converges on a homogeneous reduced form, suggesting that disparate lineages are subject to a uniform selection pressure. The primary goal of this study was to evaluate the morphology and infer the phylogeny of the Leucogastrales with Mycolevis siccigleba using a Bayesian methodology. A comprehensive morphological assessment was used for an a priori phylogenetic inference to guide the sequencing effort. All structures except spore ornamentation pointed to the Albatrellaceae as the most likely sister taxon. Polyporoletus sublividus, a close relative of Albatrellus, produces ornamented basidiospores with a similar structure to M. siccigleba basidiospores. The ITS from 30 taxa was used for the molecular phylogenetic analysis. P. sublividus was found sister to Mycolevis. Leucophleps spinispora and L. magnata formed a group sister to the Polyporoletus/Mycolevis group, whereas Leucogaster was polyphyletic with respect to the core of the Leucogastrales and sister to A. caeruleoporus. This relationship was expected as previously undescribed chlamydospores produced by members of Albatrellus had a similar morphology to the basidiospores of L. rubescens.     

下延叉蕨和芽胞叉蕨配子体发育的研究

利用光学显微镜详细观察了叉蕨属(Tectaria)下延叉蕨(Tectaria decurrens)和芽胞叉蕨(T.fauriei)的配子体发育过程,记录了配子体各发育阶段的特征。结果表明:(1)下延叉蕨和芽胞叉蕨的孢子均为单裂缝,具周壁,由周壁形成纹饰,孢子极面观椭圆形,赤道面观豆形或肾形。(2)孢子萌发方式为向心型。(3)原叶体发育方式为三叉蕨型。(4)成熟原叶体心脏形,两翼向斜上方扩展。(5)均具单细胞和多细胞毛状体,在丝状体或片状体阶段出现。研究认为,从配子体发育角度看,叉蕨属是较进化的陆生真蕨类;毛状体的类型、位置和出现时间等特征在叉蕨属种间存在差异,可作为该属种间分类的特征。     

Evolutionary relationships among aquatic anamorphs and teleomorphs: Lemonniera, Margaritispora, and Goniopila

The hypothesis that similar conidial morphologies in aquatic hyphomycetes are a result of convergent evolution was tested using molecular sequence data. Cladistic analyses were performed on partial sequences of 28S rDNA of seven species of Lemonniera, one species of Margaritispora and one species of Goniopila. Lemonniera has tetraradiate conidia with long arms, whereas Margaritispora and Goniopila have typically globose (isodiametric) conidia, with short conical protuberances in a stellate or quadrangular arrangement. Lemonniera and Margaritispora have phialidic conidiogenesis and both produce dark, minute sclerotia in culture whereas Goniopila has holoblastic conidiogenesis and does not produce sclerotia in culture. Goniopila produces a microconidial phialidic synanamorph in culture. All three genera have schizolytic conidial secession. Molecular analyses demonstrate that Lemonniera species are placed in two distinct clades: one within Leotiomycetes; the other within Pleosporales, Dothideomycetes. Margaritispora is placed with Lemonniera species within Leotiomycetes. Goniopila and Lemonniera pseudofloscula are placed within Dothideomycetes. No morphological character was entirely congruent with the molecular derived phylogeny. This suggests that for the group of species studied, conidial shape is not a reliable indicator of phylogeny but more likely the result of convergent evolution in response to the aquatic environment.     

New species of Phaeoramularia, Pseudocercospora and Stenella from Western Ghats of India

Four new species of the hyphomycete genera Phaeoramularia viz. Ph. caesalpinae, Pseudocercospora viz., Ps. tiliacearum, Stenella, viz. S. argyreiae and S. grewiae occurring on Caesalpinia bonducella Fleming (Caesalpiniaceae), Grewia sp. (Tiliaceae), Argyrea sp. Lour (Convolvulaceae) and Grewia sp. L. (Tiliaceae), respectively are described and illustrated here. All these fungi were collected from Western Ghats of India.     

A polysaccharide from Lichina pygmaea and L. confinis supports the recognition of Lichinomycetes

The lichen-forming order Lichinales, generally characterized by prototunicate asci and the development of thalli with cyanobacteria, has recently been recognized as a separate class of ascomycetes, Lichinomycetes, as a result of molecular phylogenetic studies. As alkali and water-soluble (F1SS) polysaccharides reflect phylogeny in other ascomycetes, a polysaccharide from Lichina pygmaea and L. confinis was purified and characterized to investigate whether these F1SS compounds in the Lichinomycetes were distinctive. Nuclear magnetic resonance (NMR) spectroscopy and chemical analyses revealed this as a galactomannan comprising a repeating unit consisting of an α-(1→6)-mannan backbone, mainly substituted by single α-galactofuranose residues at the O-2- or the O-2,4- positions linked to a small mannan core. With the exception of the trisubstituted mannopyranose residues previously described in polysaccharides from other lichens belonging to orders now placed in Lecanoromycetes, the structure of this galactomannan most closely resembles those found in several members of the Onygenales in Eurotiomycetes. Our polysaccharide data support molecular studies showing that Lichina species are remote from Lecanoromycetes as the galactofuranose residues are in the α-configuration. That the Lichinomycetes were part of an ancestral lichenized group can not be established from the present data because the extracted polysaccharide does not have the galactofuranose residue in the β configuration; however, the data does suggest that an ancestor of the Lichinomycetes contained a mannan and was part of an early radiation in the ascomycetes.