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1.
Ya‐Fan Chan Kuo‐Ping Chiang Jeng Chang Øjvind Moestrup Chih‐Ching Chung 《The Journal of eukaryotic microbiology》2015,62(3):318-326
Two phagotrophic euglenid strains (Strains Pac and Tam) were isolated from coastal locations in Taiwan. Ultrastructural characteristics of the strains included five pellicle strips joined at the posterior end. The strips were formed by major grooves with bifurcated edges. At the cell anterior, the feeding structure formed a lip. Underneath the lip was a comb composed of layers of microtubules. Farther back, two supporting rods tapered toward the posterior end, and a number of vanes with attached microtubules were present between the rods. The morphological characteristics agree with Ploeotia costata Strain CCAP 1265/1. However, the 18S rDNA sequences of Strains Pac/Tam lacked a group I intron and possessed three extra insertions of 116, 67, and 53 bp. Phylogenetic analysis indicated low sequence similarity between Strains Pac/Tam and CCAP 1265/1 (92%). The morphospecies P. costata apparently includes a substantial level of DNA sequence divergence, and likely represents multiple molecular species units. 相似文献
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棉铃虫18S核糖体RNA基因的序列分析及其分子系统学 总被引：3，自引：1，他引：3
克隆并分析了鳞翅目棉铃虫Helicoverpa armigera (Hübner)18S核糖体RNA基因(18S rDNA)的全序列,将该序列与鞘翅目、膜翅目、同翅目、双翅目、捻翅目和弹尾目各一种昆虫的同源保守区进行了比较。序列分析结果显示：鳞翅目和双翅目昆虫在18S rDNA结构上彼此较为相似,捻翅目昆虫的18S rDNA分子结构表现出与其它目昆虫有较大的差异,但相对与弹尾目昆虫的18S rDNA较为接近。该结果支持了有关捻翅目属于一个独立的目级分类阶元的论点。 相似文献
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利用N酰基高丝氨酸内酯(N-acyl-homoserine lactone,简称AHL)为唯一碳源和能源,筛选得到一株能够降解AHL的菌株R1。常规鉴定和18S rDNA序列分析表明,菌株R1属于红冬孢酵母菌(Rhodosporidium toruloides),定名为R.toruloidesR1。结果显示R.toruloidesR1能利用所测试的3种AHL作为唯一碳源和能源生长,具有降解AHL的能力,其对AHL依赖型胡萝卜欧文氏软腐病菌(Erwinia carotovora subsp.carotovora)的致病有一定的抑制作用。 相似文献
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从南海海域白姑鱼消化道分离到1株海洋真菌ZH2.1,对其进行了系统鉴定和生物学研究。采用传统的形态学鉴定方法,并结合18S rDNA序列分析确定其归属。18S rDNA序列分析表明其与孔状短小茎点霉Phoma exigua var.exigua在进化位置上最为接近,其18S rDNA在GenBank的登录号为FJ450059。结合形态学观察结果,可认为菌株ZH2.1为茎点霉属真菌。对该菌株的部分生物学特性研究表明,ZH2.1为兼性海洋真菌,最适生长盐度为3%。此外,在微氧条件下也可生长。 相似文献
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KAZUNORI YOSHIZAWA CHARLES LIENHARD KEVIN P. JOHNSON 《Zoological Journal of the Linnean Society》2006,146(2):287-299
Phylogenetic relationships among extant families in the suborder Trogiomorpha (Insecta: Psocodea: 'Psocoptera') were inferred from partial sequences of the nuclear 18S rDNA and Histone 3 and mitochondrial 16S rDNA genes. Analyses of these data produced trees that largely supported the traditional classification; however, monophyly of the infraorder Psocathropetae (= Psyllipsocidae + Prionoglarididae) was not recovered. Instead, the family Psyllipsocidae was recovered as the sister taxon to the infraorder Atropetae (= Lepidopsocidae + Trogiidae + Psoquillidae), and the Prionoglarididae was recovered as sister to all other families in the suborder. Character states previously used to diagnose Psocathropetae are shown to be plesiomorphic. The sister group relationship between Psyllipsocidae and Atropetae was supported by two morphological apomorphies: the presence of a paraproctal anal spine and an anteriorly opened phallosome. Based on these sequence data and morphological observations, we propose a new classification scheme for the Trogiomorpha as follows: infraorder Prionoglaridetae (Prionoglarididae), infraorder Psyllipsocetae (Psyllipsocidae), infraorder Atropetae (Lepidopsocidae, Trogiidae, Psoquillidae). © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 146 , 287–299. 相似文献
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Nemerteans (phylum Nemertea) have been viewed by mostzoologists as descended from, or closely related to,the flatworms. This view is based mainly on theirsupposedly acoelomate body. Their ancestry, however,is a point of controversy and there is evidence for acoelomate, protostomous origin. Notwithstanding thesedifferent views, most zoologists consider nemerteansto be phylogenetically distant from the chordates.Four authors (Hubrecht, Macfarlane, Jensen, Willmer),however, have postulated that nemerteans instead areclosely related to the chordates and that they sharea most recent common ancestor with the vertebrates. We argue that this view is based on a flawed view ofhomology and of seeing evolution as a series ofprogressions, which has no support in modernevolutionary thinking. Since there are nomorphological synapomorphies supporting aChordata-Nemertea clade, these authors instead guesswhat characteristics in extant nemerteans gave rise tocharacters observed in recent chordates. For example,they propose that the nemertean proboscis sheath hasevolved into the notochord. This is mere speculation,lacking testable propositions and is hence void ofinformation, and thus becomes futile in our view. However, the idea of a nemertean-vertebrate sisterrelationship as such is a testable hypotheses, and wetest it by applying the parsimony criterion to a setof morphological characters, and a set of molecular(the 18S rRNA gene) characters. Both tests reject thehypothesis. 相似文献
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利用PCR技术克隆了产紫杉醇内生真菌EFY-21的18S rDNA序列,通过同源性分析,初步确定该菌与拟盘多毛孢属(Pestalotiopsis)有较高的同源性,相似性为99%。为了进一步了解EFY-21的有关生物学特性,分别选用PDA、PSA、查氏、玉米粉琼胶、牛肉膏蛋白胨5种培养基,按照常规方法培养,用十字法测量菌落直径;同时选用查氏培养基为基本培养基,分别观察不同碳源葡萄糖、甘露醇、麦芽糖、果糖、可溶性淀粉,不同氮源KNO3、Ca(N03)2、(NH4)2SO4、NH4N03、(NH4)2HPO4、蛋白胨、尿素,不同培养温度10,15,20,25,28,30,37℃,不同pH值4,5,6,7,8,9对内生真菌菌丝的影响。试验结果表明:EFY-21在PDA培养基上生长最快,生长状况最好;供试的碳氮源中,对EFY-21菌丝生长影响的大小顺序为葡萄糖甘露醇果糖麦芽糖可溶性淀粉;蛋白胨KNO3Ca(N03)2NH4N03(NH4)2HPO4(NH4)2SO4尿素;最适培养温度为25～30℃;最适pH为5～7。 相似文献
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Ji Hye Moon Ji Hye Kim Pablo Quintela‐Alonso Jae‐Ho Jung 《The Journal of eukaryotic microbiology》2020,67(1):54-65
The morphology and morphogenesis of a new ciliate species, Neobakuella aenigmatica n. sp., which was discovered in an estuary in Korea, were investigated, using live observation, protargol impregnation, and scanning electron microscopy. This new species is characterized by a large (185–300 × 55–105 μm in vivo), elongate‐ellipsoidal, flexible but not contractile body. It has ellipsoidal, yellowish cortical granules, 1.3 × 1.0 μm in size. The species has invariably 3 frontal and 2 frontoterminal cirri, about 5–10 buccal and 1–6 parabuccal cirri, 7 midventral rows, and 1 right and 2–4 left marginal rows. The outer left marginal row(s) consists of 1–7 short rows of cirri. The nuclear apparatus comprises 130 macronuclear nodules and 2 spherical micronuclei on average. The dorsal ciliature consists of 3 dorsal kineties. The leftmost left marginal row(s) likely develops from anlagen originating from both the rightmost and leftmost left marginal row(s). The molecular phylogenetic tree based on SSU rDNA suggests the nonmonophyly of the genus Neobakuella. 相似文献
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Relationships among the morphologically diverse members of Saxifragaceae sensu lato were inferred using 130 18S rDNA sequences. Phylogenetic analyses were conducted using representatives of all 17 subfamilies of Saxifragaceae sensu lato, as well as numerous additional taxa traditionally assigned to subclasses Magnoliidae, Caryophyllidae, Hamamelidae, Dilleniidae, Rosidae, and Asteridae. This analysis indicates that Saxifragaceae should be narrowly defined (Saxifragaceae sensu stricto) to consist of ~30 herbaceous genera. Furthermore, Saxifragaceae s. s. are part of a well-supported clade (referred to herein as Saxifragales) that also comprises lteoideae, Pterostemonoideae, Ribesioideae, Penthoroideae, and Tetracarpaeoideae, all traditional subfamilies of Saxifragaceae sensu lato, as well as Crassulaceae and Haloragaceae (both of subclass Rosidae). Paeoniaceae (Dilleniideae), and Hamamelidaceae, Cercidiphyllaceae, and Daphniphyllaceae (all of Hamamelidae). The remaining subfamilies of Saxifragaceae sensu lato fall outside this clade. Francoa (Francooideae) and Bauera (Baueroideae) are allied, respectively, with the rosid families Greyiaceae and Cunoniaceae. Brexia (Brexioideae), Parnassia (Parnassioideae), and Lepuropetolon (Lepuropetaloideae) appear in a clade with Celastraceae. Representatives of Phyllonomoideae, Eremosynoideae, Hydrangeoideae, Escallonioideae, Montinioideae, and Vahlioideae are related to taxa belonging to an expanded asterid clade (Asteridae sensu lato). The relationships suggested by analysis of 18S rDNA sequences are highly concordant with those suggested by analysis of rbcL sequences. Furthermore, these relationships are also supported in large part by other lines of evidence, including embryology. serology, and iridoid chemistry. 相似文献
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应用PCR-RFLP和测序分析对川西亚高山米亚罗林区不同土地利用类型的土壤真菌18S rDNA基因进行了多样性和系统发育研究,探讨了土地利用变化对土壤真菌群落结构的影响。在20a龄云杉(Picea likiandensis var balfourianan)人工林和菜地两种类型土壤中,共得到238个阳性克隆,限制性内切酶MspI和RsaI进行RFLP分析后得到56个不同的分类操作单元(OTUs),其中20a龄云杉人工林样地获得137个阳性克隆和37个OTUs,而菜地样地获得101个阳性克隆和19个OTUs。在两类样地中具有不同的优势种群,其中20a龄云杉人工林样地有1个明显优势种群,占总克隆数的20.4%;菜地样地有2个明显优势种群,分别占总克隆数的25.7%和21.8%。对14个克隆进行了序列测定,序列的相似性在86%~99%之间,与GenBank数据库中的序列进行比对,与已知序列的相似性在92%~100%之间。系统发育分析表明,所有的18SrDNA基因被分为3个主要的簇,其中20a龄云杉人工林样地的克隆都聚集在第一和第三簇中,而菜地样地的克隆都聚集在第二簇中。结果说明,两类土壤中具有较为丰富的真菌多样性,而土地利用变化引起了土壤真菌群落结构的明显变化。 相似文献
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18-26S rDNA在4种重楼属植物中的定位 总被引：4，自引：0，他引：4
为探讨rDNA在重楼属Paris L.中的分布规律,利用荧光原位杂交（FISH）对4种重楼属植物的18-26S rDNA进行了定位。所有植物均为二倍体,基因组由A、B、C、D和E5条染色体构成。（1）滇重楼P.polyphylla var.yunnanensis:2n=10=6m+4t,C和D染色体的短臂上各有1个18-26S rDNA位点;（2）长柱重楼P.forrestii:2n=10=6m+4t,B染色体的长臂、C和D染色体的短臂上各有1个位点;（3）五指莲P.axialis:2n=10=6m（2sat）+4t（2sat）+1-2B,C和D染色体的短臂上各有1个位点;在有1个B染色体的细胞中,B染色体没有信号点,而有2个B染色体的细胞中,只有1个B染色体上有信号点,表明B染色体上有基因存在且其分裂不均等;（4）大理重楼P.daliensis:2n=10=4m+2sm+2st+2t,C染色体的短臂上有1个位点。18-26S rDNA位点不仅出现在染色体的次缢痕上,也出现在非次缢痕位点。另外,4个种中C染色体短臂末端均有18-26S rDNA。 相似文献
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Anique Stecher Stefan Neuhaus Benjamin Lange Stephan Frickenhaus Bánk Beszteri Peter G. Kroth 《欧洲藻类学杂志》2016,51(1):31-46
Sea ice is a large and diverse ecosystem contributing significantly to primary production in ice-covered regions. In the Arctic Ocean, sea ice consists of mixed multi-year ice (MYI), often several metres thick, and thinner first-year ice (FYI). Current global warming is most severe in Arctic regions; as a consequence, summer sea ice cover is decreasing and MYI is disappearing at an alarming rate. Despite its apparent hostility, sea ice is inhabited by a diverse microbial community of bacteria and protists, many of which are photosynthetic. Here we present an assessment of eukaryotic biodiversity in MYI and FYI from the central Arctic Ocean using high-throughput 454 sequencing of 18S rRNA and rDNA amplicons. We compared the rDNA-based ‘total’ biodiversity with the ‘active’ biodiversity from rRNA amplicons and found differences between them including an over-representation of Ciliophora, Bicosoecida and Bacillariophyceae operational taxonomic units (OTUs) in the active part of the community. Differences between the two libraries are more pronounced at the lower taxonomic level: certain genera, such as Melosira, are more abundant in the rRNA library, indicating activity of these genera. Furthermore, we found that one FYI station showed a higher activity of potential grazers which was probably due to the advanced stage of melt evident by higher ice temperatures and highly porous ice compared with the other stations. 相似文献
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我国汉江下游在1992、1998、2000、2003年初春曾先后多次发生水华。水华发生期间,硅藻大量增殖,形成肉眼可见的褐色颗粒悬浮于江水中,使江水呈现黄褐色,在以往的研究中认为汉江硅藻水华优势种为小环藻^[1,2],但并未从分类上展开研究。传统上硅藻种类的鉴定主要是以硅藻壳的形态及壳表面上的花纹为依据。目前国内外学者利用18S rDNA基因分析对水华赤潮原因种的鉴定方面也作了许多相关的研究。陈丽芬等利用18SrDNA序列分析确定香港海域一株棕囊藻为球形棕囊藻^[3]。 相似文献
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Maxim Kulikovskiy Yevhen Maltsev Anton Glushchenko Irina Kuznetsova Dmitry Kapustin Evgeniy Gusev Horst Lange-Bertalot Sergei Genkal John Patrick Kociolek 《Journal of phycology》2020,56(6):1601-1613
A new diatom genus, Gogorevia, is described on the basis of an integrated molecular and morphological investigation. Two species are described from Vietnam: the generitype, G. rinatii sp. nov., and G. ovalis sp. nov. These species share many morphological features with Achnanthes exigua and allied taxa that were previously transferred to the genera Achnanthidium or Lemnicola. Our current molecular investigation shows that Gogorevia is distinct and phylogenetically removed from the above-mentioned genera. Morphologically, Gogorevia differs from Achnanthidium and Lemnicola by the shape of the valves, possessing uniseriate striae, raphe morphology, and the presence of an evident sternum. The recently described species Lemnicola uniseriata is transferred to Gogorevia on the basis that it possesses the same morphological features and phylogenetic position as other members of the genus. 相似文献
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A knowledge of fish diets can contribute to revealing the trophic role and ecological function of species in aquatic ecosystems. At present, however, there are no efficient or comprehensive methods for analyzing fish diets. In this study, we investigated the diets of juvenile Scatophagus argus collected near a wharf in Daya Bay, China, by dissection and high‐throughput sequencing (HTS) using the 18S rDNA V4 region. Microscopy disclosed large amounts of bryozoans and unrecognizable detritus. In contrast, HTS analysis indicated that the fish diets were considerably more diverse than visual inspection suggested. After eliminating fish sequences, approximately 17,000 sequences from taxa in nine phyla (Ciliophora, Bryozoa, Annelida, Bacillariophyta, Chlorophyta, Arthropoda, Dinoflagellata, Tunicata, and Phaeophyta) were identified from the analysis of stomach contents. Twenty‐one food categories were identified, most of which (95.2%) were benthic fouling organisms that could easily be collected around wharfs. These consisted of bryozoans (31.9%), ciliates (45.7%), polychaetes (14.6%), and green algae (3.0%). Therefore, to adapt to anthropogenic habitat modification, the fish had probably shifted from planktonic to benthic feeding. The prevalence of fouling organisms in the stomachs of juvenile S. argus indicates that the fish have responded to habitat changes by widening their food spectrum. This adaptation may have increased their chances of survival. The fouling organisms that inhabit highly perturbed coastal ecosystems could represent a food source for animals at higher trophic levels. Our results accordingly suggest that human activity might significantly influence fish feeding behavior and material transfer along the food chain. 相似文献
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Sebastiaan W. Rampen Stefan Schouten F. Elda Panoto Maaike Brink Robert A. Andersen Gerard Muyzer Ben Abbas Jaap S. Sinninghe Damsté 《Journal of phycology》2009,45(2):444-453
The phylogenetic position of diatoms belonging to the genus Attheya is presently under debate. Species belonging to this genus have been placed in the subclasses Chaetocerotophycidae and Biddulphiophycidae, but published phylogenetic trees based on 18S rDNA, morphology, and sexual reproduction indicate that this group of diatoms may be a sister group of the pennates. To clarify the position of Attheya, we studied the morphology, 18S rDNA, 16S rDNA of the chloroplasts, the rbcL large subunit (LSU) sequences of the chloroplasts, and the sterol composition of three different strains of Attheya septentrionalis (Østrup) R. M. Crawford and one strain of Attheya longicornis R. M. Crawford et C. Gardner. These data were compared with data from more than 100 other diatom species, covering the whole phylogenetic tree, with special emphasis on species belonging to the genera that have been suggested to be related to the genus Attheya. All data suggest that the investigated Attheya species form a separate group of diatoms, and there is no indication that they belong to either the Chaetocerotophycidae or the Biddulphiophycidae. Despite applying these various approaches, we were unable to determine the exact phylogenetic position of the investigated Attheya species within the diatoms. 相似文献
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Iiyama K Chieda Y Yasunaga-Aoki C Hayasaka S Shimizu S 《The Journal of eukaryotic microbiology》2004,51(6):598-604
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The phylogenetic position of the Tardigrada remains uncertain. This is due to the limited information available, and the uncertainty of whether some characters are homologous or analogous with other taxa. Based on some morphological characters, current discussion centres on whether the taxon branches from the annelid-arthropod lineage, or lies within the arthropod complex. The molecular data presented here from an analysis of the 18S rRNA gene sequences are used to test the validity of these two hypotheses. Phylogenetic inference by the maximum parsimony and distance (neighbour-joining) methods suggests that the Tardigrada is a sister group of the major protostome eucoelomate assemblage that emerged before the arthropods, annelids, molluscs, and sipunculids evolved. The tardigrade clade also appears as an independent lineage separate from the nematode clade, thus supporting the current idea that tardigrades do not have a close aschelminth relationship. The molecular data also imply that several morphological features, considered significant in determining the phylogenetic relationships of tardigrades, are not synapomorphic characters. 相似文献