9株鱼源鰤诺卡氏菌生物学特征和致病性比较

【背景】鰤诺卡氏菌(Nocardia seriolae)是一种革兰氏阳性好氧菌,易引起鲈形目鱼类结节病发生,近几年对大口黑鲈、杂交鳢等名优鱼类的危害越来越大。【目的】比较分析9株不同年份、不同地区患结节病的不同淡水鱼品种分离的鰤诺卡氏菌的种间同源关系、生长特性、致病性以及药物敏感性差异,为进一步研究制定相应的防控与治疗措施提供基础数据和科学依据。【方法】在9株试验菌生理生化实验鉴定结果基础上,采用16SrRNA基因序列比对、限制性片段长度多样性比较菌株间的同源性;扩增看家基因secA1基因序列进行不同来源菌株种内相似度比对;通过体外培养比较不同菌株的生长情况;人工注射感染分析9株试验菌对大口黑鲈的致病性差异;采用微量肉汤二倍稀释法测试9株试验菌对13种抗菌药物的最小抑菌浓度;运用PCR技术检测菌株携带毒力基因和耐药基因的情况。【结果】生理生化结果显示9株试验菌与鰤诺卡氏菌的基本理化特征相符;9株试验菌聚类分析聚为一类,种内相似度高,限制性片段长度多样性酶切图谱相同,生长特性无明显差异;9株试验菌对大口黑鲈致病性无显著差异,但毒力基因携带情况略有不同,其均携带mce1A、mig和pup基因,而dop和whiB3只在部分菌株检出;9株试验菌均对氟甲喹和氨苄西林耐药,除NS1外,都对磺胺间甲氧嘧啶耐药,对大部分抗菌药物敏感,主要携带blaTEM和sul1耐药基因。【结论】不同时间、不同地区及不同宿主分离的9株鰤诺卡氏菌在生物学特性、致病性和药物敏感性等方面无明显差异;同源性相近,提示华南地区感染淡水鱼的鰤诺卡氏菌可能为同一流行株型。研究结果为鰤诺卡氏菌的发病机制及防控技术的进一步研究奠定了基础。     

四株杂交鳢致病性舒伯特气单胞菌特性及致病性比较

【背景】舒伯特气单胞菌为革兰氏阴性短杆菌,是一种人-畜-鱼共患的条件性致病菌,它能引起不同程度的人类疾病,近年来更是在水产养殖中被频繁报道。【目的】比较分析4株杂交鳢源舒伯特气单胞菌(WL-4、ZL-1、ZL-13、D075)菌株间生理生化特性、致病性以及对常用药物的敏感性差异,为水产舒伯特气单胞菌病的防治提供参考依据。【方法】使用全自动细菌生化鉴定仪检测菌株的生理生化特性;运用PCR扩增和测序比对菌株的gyrB、16S rRNA基因序列;采用改良平板法检测毒力因子表达,PCR技术检测菌株毒力基因和耐药基因的携带情况;通过人工注射感染分析4株舒伯特气单胞菌对杂交鳢的致病性差异;并采用微量二倍稀释法测试15种抗菌药物对菌株的最小抑菌浓度。【结果】以ATCC43700 (人源舒伯特气单胞菌)作为参考,4株菌株理化特性基本相同,gyrB和16SrRNA基因一致性分别为99.57%和100%,聚类分析聚为一簇;不同的舒伯特气单胞菌(ATCC43700、WL-4、ZL-1、ZL-13、D075)均具有溶血性、蛋白酶活性和脂肪酶活性;但人源菌株(ATCC43700)与杂交鳢源舒伯特气单胞菌携带的毒力基因存在差异,其中人源菌株携带了hlyA、ela、lip、ahal、act,而杂交鳢源菌株(WL-4、ZL-1、ZL-13、D075)携带hlyA、ela、lip、ahal、aer;4株杂交鳢源舒伯特气单胞菌对杂交鳢致病性存在差异,1.2×10~5CFU/mL浓度腹腔注射感染健康杂交鳢,WL-4、ZL-1、ZL-13、D075对杂交鳢的感染致死率依次为30%、40%、70%和80%;不同菌株(ATCC43700、WL-4、ZL-1、ZL-13、D075)的药物敏感性以及携带的耐药基因也存在差异。【结论】4株杂交鳢源舒伯特气单胞菌在致病性、药物敏感性等方面存在差异,研究结果有助于进一步开展舒伯特气单胞菌病发病机制和防控技术研究。     

埃莎霉素Ⅰ组分高含量、高产量基因工程菌WSJ-IA及其原株的鉴定

【目的】利用调节基因acyB2激活异戊酰基转移酶(ist)基因表达的特点,将ist与调节基因acyB2在异戊酰螺旋霉素(埃莎霉素)Ⅰ产生菌菌株中共表达,获得埃莎霉素Ⅰ单组分的高含量及高产量菌株WSJ-IA。对其及原始螺旋霉素产生菌菌株Streptomyces spiramyceticus F21进行了初步鉴定。【方法】从形态学、培养和生理生化特征、细胞壁化学组成、16S rRNA基因序列、5个看家基因(atpD、gyrB、rpoB、recA和trpB)蛋白分析和系统发育树构建等方面对该菌株及其原株进行了鉴定。【结果】两株菌在形态培养特征、生理生化特征、细胞壁化学组成、16S rRNA基因序列和5个看家基因蛋白水平基本一致,在系统发育树分析中同处在一个分支中。而在16S rRNA基因序列和5个看家基因蛋白水平在系统发育上它们均与已知相近菌株处于不同的分支上,并且与不同基因的相近菌株各有不同,其中无一报道产生螺旋霉素。【结论】Streptomyces spira-myceticus F21可能是一个产生螺旋霉素的链霉菌新种,16S rRNA基因序列和5个看家基因蛋白序列分析可以作为埃莎霉素Ⅰ基因工程菌生产过程中进行鉴别的分子标志。     

埃莎霉素I组分高含量、高产量基因工程菌WSJ-IA及其原株的鉴定

【目的】利用调节基因acyB2激活异戊酰基转移酶(ist)基因表达的特点, 将ist与调节基因acyB2在异戊酰螺旋霉素(埃莎霉素)Ⅰ产生菌菌株中共表达, 获得埃莎霉素Ⅰ单组分的高含量及高产量菌株WSJ-IA。本研究对其及原始螺旋霉素产生菌菌株Streptomyces spiramyceticus F21进行了初步鉴定。【方法】从形态学、培养和生理生化特征、细胞壁化学组成、16S rRNA基因序列、5个看家基因(atpD、gyrB、rpoB、recA和trpB)蛋白分析和系统发育树构建等方面对该菌株及其原株进行了鉴定。【结果】两株菌在形态培养特征、生理生化特征、细胞壁化学组成、16S rRNA基因序列和5个看家基因蛋白水平基本一致, 在系统发育树分析中同处在一个分支中。而在16S rRNA基因序列和5个看家基因蛋白水平在系统发育上它们均与已知相近菌株处于不同的分支上, 并且与不同基因的相近菌株各有不同, 其中无一报道产生螺旋霉素。【结论】Streptomyces spiramyceticus F21可能是一个产生螺旋霉素的链霉菌新种, 16S rRNA基因序列和5个看家基因蛋白序列分析可以作为埃莎霉素I基因工程菌生产过程中进行鉴别的分子标志。     

鳜源致病性舒伯特气单胞菌的分离鉴定及药敏试验

【背景】舒伯特气单胞菌(Aeromonas schubertii)广泛分布于淡、海水水体和底泥中,致病株已在我国养殖鳢科鱼类中流行,也感染其他经济鱼类,导致暴发性死亡。【目的】对病鳜(Siniperca chuatsi)的病原进行鉴定,确定分离菌的致病性及药物敏感性,为该病临床治疗提供参考。【方法】采集病鳜脾肾组织进行PCR或RT-PCR扩增其常见病毒,采集病鳜肝脏和腹水分离培养细菌,PCR扩增代表菌株的gyrB、16S rRNA和毒力基因,鉴定其生理生化特征,并进行药物敏感性试验和人工感染试验。【结果】病鳜的传染性脾肾坏死病毒、鳜蛙病毒、鳜弹状病毒检测结果为阴性,肝脏和腹水均存在大量细菌;代表菌株Gui210820被鉴定为舒伯特气单胞菌,携带溶血素、气溶素、弹性蛋白酶和磷脂酶毒力基因,腹腔注射感染鳜的半数致死浓度(LD50)为3.16×105 CFU/mL;菌株Gui210820对四环素、卡那霉素、复方新诺明等6种抗菌药物耐药,对强力霉素中介,对恩诺沙星、新霉素、氟苯尼考等11种抗菌药物敏感。【结论】本试验从病鳜组织分离到致病性舒伯特气单胞菌,水产准许用药物恩诺沙星、新霉素、氟苯尼考...     

杜仲黑斑病菌(Pestalotiopsis trachicarpicola)拮抗细菌的分离和鉴定

【背景】杜仲黑斑病菌(Pestalotiopsis trachicarpicola)是引起杜仲黑斑病的新病原,当前尚未见生防菌对其产生拮抗作用的报道。【目的】从杜仲健康叶片上分离筛选出对P.trachicarpicola DZHBB-1拮抗效果最好的生防芽孢杆菌(Bacillussp.),利用16SrRNA基因结合蛋白质编码基因,实现对该菌株的快速准确鉴定。【方法】采用稀释分离法从健康杜仲叶片上分离菌株,通过平板对峙实验和生长速率法进行筛选,联合16SrRNA、gyrA、gyrB基因序列构建系统发育树分析,结合形态学特征及生理生化特性鉴定目标菌株,盆栽试验验证其对杜仲黑斑病的防治效果。【结果】总共分离得到62株芽孢杆菌,初筛出14株对病原菌有较好生防效果的菌株,复筛结果证明菌株J1拮抗效果最好且稳定,抑制率达到66.67%,16SrRNA、gyrA、gyrB基因序列系统发育树分析结果综合显示,菌株J1为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。盆栽试验结果显示,该菌能有效防治杜仲黑斑病的发生,防治效果均超过57%。【结论】该菌株具有防治P. trachicarpicola引起相关植物病害的生防潜力,16S rRNA、gyrA、gyrB基因联合鉴定芽孢杆菌,可为快速准确地鉴定芽孢杆菌及其近缘种提供借鉴方法。     

鲫源迟缓爱德华氏菌的分离鉴定及其毒力基因的检测

【目的】探明上海某养殖场的异育银鲫(Carassius auratus gibelio)发生死亡的病因,研究致病菌分类地位和毒力基因携带情况。【方法】通过病原菌的筛查和回感试验,确定发病原因,对16S rRNA基因、gyrB和rpoB管家基因测序,建立病原菌系统进化树,结合API-32E细菌鉴定系统对菌株的生理生化进行鉴定,综合判定致病菌的种类及其分类地位;根据已报道的7个毒力基因fimA、citC、gadB、mukF、katB、esrB和sodB序列,设计引物进行PCR扩增,研究病原菌毒力基因携带情况。【结果】致病菌GY15是导致异育银鲫发病的原因,GY15的16S rRNA、gyrB和rpoB基因与已报道的迟缓爱德华氏菌(Edwardsiella tarda)相似性在99%以上,构建系统进化树和API鉴定确定该菌株为E.tarda,腹腔注射回感可导致异育银鲫死亡,半致死浓度(LD_(50))为4.26×105 CFU/m L;已报道的7种毒力基因在该致病菌中均能被检测到;药敏试验结果显示,该菌对恩诺沙星、氟苯尼考和氧氟沙星等15种药物敏感,对新霉素、四环素和复方新诺明等18种药物表现为耐药。【结论】首次报道E.tarda可感染异育银鲫,它对异育银鲫的养殖造成威胁。     

河南省白龟山水库下游水体氨化细菌分离鉴定及其降解有机氮条件

【目的】从河南省白龟山水库下游水体中分离筛选氨化细菌,并研究其降解有机氮的条件。【方法】利用选择性培养基从微污染水源水中筛选氨化细菌,进一步比较了不同氨化细菌降解有机氮的效果;采用单因子法研究菌株N24降解有机氮的条件;通过形态、生理生化特征及16S rRNA基因序列分析对菌株N24进行鉴定。【结果】从微污染水源水中分离筛选到4株氨化细菌,其中菌株N24培养48 h后氨氮浓度较高,达到138.926 mg/L。菌株N24降解有机氮最适温度为30-35°C,最适初始pH值为6.0,500 mL摇瓶最适装液量75 mL。菌株N24被鉴定为弯曲芽孢杆菌(Bacillus flexus,GenBank登录号:JX291240.1),其16S rRNA基因序列与基因库中芽孢杆菌属菌株的16S rRNA基因序列有99%-100%的相似性,与弯曲芽孢杆菌(Bacillus flexus IFO15717T,GenBank登录号:NR024691.1)的遗传距离最近。【结论】菌株N24是一株高效降解有机氮的弯曲芽孢杆菌;本研究丰富了降解有机氮菌种资源,可为该菌在环境工程领域的实际应用提供理论基础。     

一株海洋低温葡萄糖氧化酶菌株的筛选、鉴定及部分酶学性质

【目的】从海洋样品中分离筛选出产葡萄糖氧化酶菌株。【方法】采用双层平板筛选法进行初筛、复筛确定一株酶活较好的菌株,命名为GOD2(Glucose oxidase)。通过形态学、生理生化特征及16S rRNA基因序列分析研究其分类地位,并对其产生的葡萄糖氧化酶进行分离纯化和部分酶学性质的研究。【结果】细菌GOD2为产葡萄糖氧化酶菌株且遗传稳定,初步鉴定该菌株为假单胞杆菌(Pseudomonas migulae),其所产酶最适反应温度为20°C,热稳定性较差,40°C剩余相对酶活80%;超过40°C酶活力迅速下降。【结论】GOD2是一株极具研究价值的产低温葡萄糖氧化酶菌株。目前没有关于利用该菌生产葡萄糖氧化酶的报道。     

一株高效DEHP降解菌的分离、鉴定及其降解特性

【目的】分离得到高效的邻苯二甲酸二乙基己基酯(DEHP)降解菌。【方法】采用富集培养法筛选分离菌株,并对菌株进行驯化;通过PCR扩增得到其16S rRNA和gyrB基因序列,进行同源序列分析及分子系统发育树的构建,同时结合形态学观察和生理生化实验对菌株进行初步鉴定;采用高效液相色谱(HPLC)分析菌株对DEHP的降解特性。【结果】分离得到一株能以DEHP为唯一碳源和能源生长的菌株,命名为HS-NH1,初步鉴定其为戈登氏菌(Gordoniasp.)。菌株HS-NH1最适的生长和降解条件为30°C、pH 7.0,在此条件下,该菌株60 h内能够将浓度为500 mg/L的DEHP降解90%以上。高效液相色谱(HPLC)分析表明,菌株HS-NH1在降解DEHP过程中产生了一种重要的中间代谢产物——邻苯二甲酸。底物广谱性试验证明,菌株HS-NH1能够有效地利用多种常见的邻苯二甲酸酯(PAEs)与芳香族衍生物。【结论】筛选得到了一株DEHP降解菌Gordonia sp.HS-NH1,该菌降解效率高,具有良好的底物广谱性,在邻苯二甲酸酯类化合物的污染治理中将会有一定的应用潜力。     

Phylogeny, biogeography, and species boundaries within the Alexandrium minutum group

The geographic range and bloom frequency of the toxic dinoflagellate Alexandrium minutum and other members of the A. minutum group have been increasing over the past few decades. Some of these species are responsible for paralytic shellfish poisoning (PSP) outbreaks throughout the world. The origins of new toxic populations found in previously unaffected areas are typically not known due to a lack of reliable plankton records with sound species identifications and to the lack of a global genetic database. This paper provides the first comprehensive study of minutum-group morphology and phylogeny on a global scale, including 45 isolates from northern Europe, the Mediterranean, Asia, Australia and New Zealand.Neither the morphospecies Alexandrium lusitanicum nor A. angustitabulatum was recoverable morphologically, due to large variation within and among all minutum-group clonal strains in characters previously used to distinguish these species: the length:width of the anterior sulcal plate, shape of the 1′ plate, connection between the 1′ plate and the apical pore complex, and the presence of a ventral pore. DNA sequence data from the D1 to D2 region of the LSU rDNA also fail to recognize these species. Therefore, we recommend that all isolates previously designated as A. lusitanicum or A. angustitabulatum be redesignated as A. minutum. A. tamutum, A. insuetum, and A. andersonii are clearly different from A. minutum on the basis of both genetic and morphological data.A. minutum strains from Europe and Australia are closely related to one another, which may indicate an introduction from Europe to Australia given the long history of PSP in Europe and its recent occurrence in Australia. A minutum from New Zealand and Taiwan form a separate phylogenetic group. Most strains of A. minutum fit into one of these two groups, although there are a few outlying strains that merit further study and may represent new species. The results of this paper have greatly improved our ability to track the spread of A. minutum species and to understand the evolutionary relationships within the A. minutum group by correcting inaccurate taxonomy and providing a global genetic database.     

Pleosporales in Japan (5): Pleomassaria, Asteromassaria, and Splanchnonema

Eight species in Pleomassariaceae are described and illustrated. They are Pleomassaria maxima, Pl. swidae, Pl. siparia “type A,” Prosthemium canba, Asteromassaria macroconidica, A. pulchra, Splanchnonema mori, and S. argus. Of these, Pl. swidae on twigs of Swida controversa, Pr. canba on Betula ermanii, and A. macroconidica on twigs of Prunus ×yedoensis and an unknown woody plant are new. Three species, Pl. siparia “type A,” A. pulchra, and S. argus, are reported from Japan for the first time. A new combination, S. mori (≡ Massaria mori), is proposed.     

The larval development of an Australian limnadiid clam shrimp (Crustacea, Branchiopoda, Spinicaudata), and a comparison with other Limnadiidae

The adult morphology of the Australian Limnadopsis shows some remarkable differences to that of other Limnadiidae. These differences are not reflected in its larval development. In Limnadopsis parvispinus, larval development comprises six stages. In stages I and II only the three naupliar appendages are present: the antennule as a small bud, the biramous antenna as the main swimming organ, and the mandible. The antennal protopod bears two endites, the proximal naupliar process and a more distal endite. In stage III a bifid naupliar process (in earlier stages not bifid) and the first signs of the carapace and trunk limb anlagen (undifferentiated rudiments) appear. In stage IV the carapace anlagen become more pronounced. The number of trunk limb anlagens increases to five, and differentiation has commenced. In stage V the first five pairs of trunk limbs are differentiated to varying degrees. The anterior-most four pairs of trunk limbs are subdivided into five endites, a small endopod, an exopod and an epipod. The bivalved carapace covers the anterior-most limbs. In larval stage VI the carapace is larger and the trunk limbs are further differentiated. A general pattern in the sequence of larval stages is the increasing number of sensilla on the antennules. From the last larval to the first postlarval stage, a significant change in morphology takes place. The trunk limbs are now used for swimming. Typical larval organs are much smaller than in the last larval stage. A comparison with other representatives of the Limnadiidae shows a high degree of correspondence, with most differences explained by the heterochronous appearance of characters during development. Five to seven stages are described for all studied Limnadiidae, including one particular stage in which four fully developed setae, a bifid naupliar process and the first signs of carapace anlagen are present. These characters are found in stage III in L. parvispinus, Limnadia stanleyana, Eulimnadia texana, and Imnadia yeyetta but in stage IV in E. braueriana and L. lenticularis. Based on a comparison of the larval stages of six limnadiid and one cyzicid species, we conclude that at least six naupliar stages belong to the limnadiid ground pattern.     

Carbon assimilation, nitrogen, and photochemical efficiency of different Himalayan tree species along an altitudinal gradient

In the area of Jumla region in Western Nepal, measurements of saturated leaf net photosynthetic rate (P_sat), nitrogen content, leaf fluorescence, carbon isotopic composition, and water status were performed on woody coniferous (Pinus wallichiana, Picea smithiana, Abies spectabilis, Juniperus wallichiana, Taxus baccata), evergreen (Quercus semecarpifolia, Rhododendron campanulatum), and deciduous broadleaved species (Betula utilis, Populus ciliata, Sorbus cuspidata) spreading from 2 400 m up to the treeline at 4 200 m a.s.l. With the exception of J. wallichiana, P_sat values were lower in coniferous than broadleaved species. Q. semecarpifolia, that in this area grows above the coniferous belt between 3 000 and 4 000 m, showed the highest P_sat at saturating irradiance and the highest leaf N content. This N content was higher and P_sat lower than those of evergreen oak species of tempe forests at middle and low altitudes. For all species, P_sat and N content were linearly correlated, but instantaneous nitrogen use efficiency was lower than values measured in lowland and temperate plant communities. The values of carbon isotopic composition, estimated by ₁₃C, showed the same range reported for temperate tree species. The ranking of ₁₃C values for the different tree types was conifers < evergreen broadleaved13C were found along the altitudinal gradient. Quantum yield of photochemistry at saturating irradiance, measured by leaf fluorescence (F/F_m), was highest in J. wallichiana and lowest in T. baccata. Overall, photochemical efficiency was more strongly related to species than to altitude. Interestingly, changes of .F/F_m along the altitudinal gradient correlated well with the reported altitudinal distribution of the species.This revised version was published online in March 2005 with corrections to the page numbers.     

A new fungal genus, Teracosphaeria, with a phialophora-like anamorph (Sordariomycetes, Ascomycota)

The new genus and species Teracosphaeria petroica is described for a perithecial ascomycete and its anamorph occurring on decayed wood collected in New Zealand. The fungus produces immersed, non-stromatic ceratosphaeria-like perithecia in nature, with hyaline, septate ascospores produced in unitunicate, non-amyloid asci. The anamorph produced in vitro is phialophora-like with lightly pigmented phialides terminating in flaring, deep collarettes that are often noticeably brown with conspicuous periclinal thickening. Phylogenetic analysis of LSU rDNA sequence data indicates that this fungus is distinct from morphologically similar fungi classified in the Chaetosphaeriales, the Trichosphaeriales or the Magnaporthaceae. It forms a monophyletic group with recently described, chaetosphaeria-like ascomycetes, such as the pyrenomycete genus Mirannulata, and shows affinity with the anamorphic species Dictyochaeta cylindrospora. The usefulness of describing anamorph genera for morphologically reduced anamorphs, when anamorph characteristics are actually part of the holomorph diagnosis, is discussed. An apparently contradictory example of the so-called Cordana and Pseudobotrytis anamorphs of Porosphaerella spp. is also discussed.     

Removal of wastewater pathogen indicators in a constructed wetland in Leon, Spain

This paper studies the seasonal presence and removal of the pathogenous micro-organisms Escherichia coli, total coliforms (TC), Clostridium perfringens (Cp), faecal streptococci (FS), Giardia cysts, Cryptosporidium oocysts and helminth eggs, in a constructed wetland treatment system. The removal efficiency of this system with respect to the indicator micro-organisms achieved maximum values in spring and autumn at 99.9% for E. coli and TC, respectively, in winter at 97.0% for FS, in summer at 100% for Clostridium and throughout the year, also at 100%, in the case of Giardia cysts, Cryptosporidium oocysts and helminth eggs. In general, very low protozoan and helminth egg counts were found, and the system demonstrated efficient reduction of the wastewater indicator pathogens.     

Endophytic fungi occurring in fennel, lettuce, chicory, and celery — commercial crops in southern Italy

The occurrence of endophytic fungi in fennel, lettuce, chicory, and celery crops was investigated in southern Italy. A total of 186 symptomless plants was randomly collected and sampled at the stage of commercial ripeness. Fungal species of Acremonium, Alternaria, Fusarium, and Plectosporium were detected in all four crops; Plectosporium tabacinum was the most common in all crop species and surveyed sites. The effect of eight endophytic isolates (five belonging to Plectosporium tabacinum and three to three species of Acremonium) inoculated on lettuce plants grown in gnotobiosis was assessed by recording plant height, root length and dry weight, collar diameter, root necrosis, and leaf yellowing. P. tabacinum and three species of Acremonium, inoculated on gnotobiotically grown lettuce plants, showed pathogenic activity that varied with the fungal isolate. Lettuce plants inoculated with the isolates Ak of Acremonium kiliense, Ac of Acremonium cucurbitacearum, and P35 of P. tabacinum showed an increased root growth, compared to the non-inoculated control. The high frequency of P. tabacinum isolation recorded in lettuce plants collected in Bari and Metaponto, and in fennel plants from Foggia agricultural districts, suggests a relationship not only between a crop species and P. tabacinum, but also between the occurrence of the endophyte and the crop rotation history of the soil.     

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.