bluuebunny/crossref_metadata_2025 huggingface dataset:
Irreversible UV Inactivation of Cryptosporidium spp. Despite the Presence of UV Repair Genes1
Authors: ROCHELLE PAUL A. , FALLAR DAFFODIL , MARSHALL MARILYN M. , MONTELONE BETH A. , UPTON STEVE J. , WOODS KEITH
Published: July 2005

Ultraviolet light is being considered as a disinfectant by the water industry because it appears to be very effective for inactivating pathogens, including Cryptosporidium parvum. However, many organisms have mechanisms for repairing ultraviolet light‐induced DNA damage, which may limit the utility of this disinfection technology. Inactivation of C. parvum was assessed by measuring infectivity in cells of the human ileocecal adenocarcinoma HCT‐8 cell line, with an assay targeting a heat shock protein gene and using a reverse transcriptase polymerase chain reaction to detect infections. Oocysts of five different isolates displayed similar sensitivity to ultraviolet light. An average dosage of 7.6 mj/cm2 resulted in 99.9% inactivation, providing the first evidence that multiple isolates of C. parvum are equally sensitive to ultraviolet disinfection. Irradiated oocysts were unable to regain pre‐irradiation levels of infectivity, following exposure to a broad array of potential repair conditions, such as prolonged incubation, pre‐infection excystation triggers, and post‐ultraviolet holding periods. A combination of data‐mining and sequencing was used to identify genes for all of the major components of a nucleotide excision repair complex in C. parvum and Cryptosporidium hominis. The average similarity between the two organisms for the various genes was 96.4% (range, 92–98%). Thus, while Cryptosporidum spp. may have the potential to repair ultraviolet light‐induced damage, oocyst reactivation will not occur under the standard conditions used for storage and distribution of treated drinking water.
Mixotrophy in the Phototrophic Harmful Alga Cochlodinium polykrikoides (Dinophycean): Prey Species, the Effects of Prey Concentration, and Grazing Impact
Authors: JEONG HAE JIN , YOO YEONG DU , KIM JAE SEONG , KIM TAB HOON , KIM JONG HYEOK , KANG NAM SEON , YIH WONHO
Published: July 2005

We first reported here that the harmful alga Cochlodinium polykrikoides, which had been previously known as an autotrophic dinoflagellate, was a mixotrophic species. We investigated the kinds of prey species and the effects of the prey concentration on the growth and ingestion rates of C. polykrikoides when feeding on an unidentified cryptophyte species (Equivalent Spherical Diameter, ESD = 5.6 μm). We also calculated grazing coefficients by combining field data on abundances of C. polykrikoides and co occurring cryptophytes with laboratory data on ingestion rates obtained in the present study. Cocholdinium polykrikoides fed on prey cells by engulfing the prey through the sulcus. Among the phytoplankton prey offered, C. polykrikoides ingested small phytoplankton species that had ESD's ≤ 11 μm (e.g. the prymnesiophyte Isochrysis galbana, an unidentified cryptophyte, the cryptophyte Rhodomonas salina, the raphidophyte Heterosigma akashiwo, and the dinoflagellate Amphidinium carterae). It did not feed on larger phytoplankton species that had ESD's ≥ 12 μm (e.g. the dinoflagellates Heterocapsa triquetra, Prorocentrum minimum, Scrippsiella sp., Alexandrium tamarense. Prorocentrum micans, Gymnodinium catenatum, Akashiwo sanguinea, and Lingulodinium polyedrum). Specific growth rates of C. polykrikoides on a cryptophyte increased with increasing mean prey concentration, with saturation at a mean prey concentration of approximately 270 ng C ml−1 (i.e. 15,900 cells ml−1)‐ The maximum specific growth rate (mixotrophic growth) of C. polykrikoides on a cryptophyte was 0.324 d∼’, under a 14:10 h light‐dark cycle of 50 μE m−2 s−1, while its growth rate (phototrophic growth) under the same light conditions without added prey was 0.166 d−. Maximum ingestion and clearance rates of C. polykrikoides on a cryptophyte were 0.16 ng C grazer−1d 1 (9.4 cells grazer 1d−1) and 0.33 μ1 grazer 1h−1, respectively. Calculated grazing coefficients by C. polykri koides on cryptophytes were 0.001–0.745 h−1 (i.e. 0.1–53% of cryptophyte populations were removed by a C. polykrikoides population in 1 h). The results of the present study suggest that C. polykrikoides sometimes has a considerable grazing impact on populations of cryptophytes.
Infection of Mouse Dermal Fibroblasts by the Monoxenous Trypanosomatid Protozoa Crithidia deanei and Herpetomonas roitmani
Authors: SANTOS DILVANI O. , BOURGUIGNON SAULO C. , CASTRO HELENA CARLA , SILVA JONATAN S. , FRANCO LEONARDO S. , HESPANHOL RENATA , SOARES MAURILIO J. , CORTE‐REAL SUZANA
Published: July 2005

Traditionally, monoxenous trypanosomatid protozoa are not believed to infect vertebrate cells. Using light and electron microscopy, we show that the monoxenous trypanosomatids Crithidia deanei and Herpetomonas roitmani are able to infect dermal mouse fibroblasts in vitro. We present experimental evidence of phagocytosis of these trypanosomatids, and demonstrate their survival in vertebrate cells. This paper raises the question about the role of C. deanei and H. roitmani, and perhaps other monoxenous trypanosomatid species, in opportunistic infections of immunocompromised individuals and cutaneos lesions in vertebrate hosts.Key Words. In vitro infection, monoxenous trypanosomatids, optical and electron microscopy.
Soil Ciliate Species Richness and Abundance Associated with the Rhizosphere of Different Subtropical Plant Species
Authors: ACOSTA‐MERCADO DIMARIS , LYNN DENIS H.
Published: July 2005

Soil protozoa, and ciliates in particular, represent a microbial group abundant in the rhizosphere with an influential role on nutrient cycling. Under laboratory conditions, ciliates regulate the size and the composition of bacterial communities, and appear to stimulate ammonification and nitrification. In spite of their important ecological role, our understanding about the factors that control their diversity and abundance in natural forest ecosystems is still rudimentary. Plant species‐specific interactions have been demonstrated between plants and soil bacteria and mycorrhizal fungi, due in part to the release of phytohormones and C‐ and N‐rich exudates. We tested the hypothesis that the rhizosphere environments of different plant species also influence the species richness and abundance of soil ciliates. Plant effect, soil pH, moisture content, microbial biomass C, and inorganic nitrogen were measured among five plant species to determine the best predictor variables for soil ciliate species richness and total abundance in a subtropical moist forest in Puerto Rico. Based on an analysis of variance, we rejected the hypothesis that there was a plant species‐specific effect on soil ciliates, unlike other microbial groups mentioned above. Using multiple regression analysis, we demonstrated that the flush of total inorganic nitrogen was the best predictor variable for both species richness and abundance of ciliates.
Current Progress in the Fatty Acid Metabolism in Cryptosporidium parvum1
Authors: ZHU GUAN
Published: July 2005

Cryptosporidium parvum is one of the apicomplexans that can cause severe diarrhea in humans and animals. The slow development of anti‐cryptosporidiosis chemotherapy is primarily due to the poor understanding on the basic metabolic pathways in this parasite. Many well‐defined or promising drug targets found in other apicomplexans are either absent or highly divergent in C. parvum. The recently discovered apicoplast and its associated Type n fatty acid synthetic enzymes in Plasmodium, Toxoplasma, and Eimeria apicomplexans are absent in C. parvum, suggesting this parasite is unable to synthesize fatty acids de novo. However, C. parvum possesses a giant Type I fatty acid synthase (CpFASl) that makes very long chain fatty acids using mediate or long chain fatty acids as precursors. Cryptosporidium also contains a Type I polyketide synthase (CpPKSl) that is probably involved in the production of unknown polyketide(s) from a fatty acid precursor. In addition to CpFASl and CpPKSl, a number of other enzymes involved in fatty acid metabolism have also been identified. These include a long chain fatty acyl elongase (LCE), a cytosolic acetyl‐CoA carboxylase (ACCase), three acyl‐CoA synthases (ACS), and an unusual “long‐type” acyl‐CoA binding protein (ACBP), which allows us to hypothetically reconstruct the highly streamlined fatty acid metabolism in this parasite. However, C. parvum lacks enzymes for the oxidation of fatty acids, indicating that fatty acids are not an energy source for this parasite. Since fatty acids are essential components of all biomembranes, molecular and functional studies on these critical enzymes would not only deepen our understanding on the basic metabolism in the parasites, but also point new directions for the drug discovery against C. parvum and other apicomplexan‐based diseases.
Trichonosema algonquinensis n. sp. (Phylum Microsporidia) in Pectinatella magnificd (Bryozoa: Phylactolaemata) from Algonquin Park, Ontario, Canada
Authors: DESSER SHERWIN S. , KOEHLER ANNE , BARTA JOHN R. , KAMYAB JUBIN , RINGUETTE MAURICE J.
Published: July 2005

A new species of microsporidian, Trichonosema algonquinensis, is described from a freshwater bryozoan, Pectinatella magnifica from Ontario, Canada. The parasite develops in epithelial cells and appears as white, spherical masses throughout the tissues. Trichonosema algonquinensis is diplokaryotic, diploblastic and undergoes development in direct contact with the cytoplasm of the host cell. Mature spores are ovoid, tapered at one end, and measure 8.5 ± 0.3 × 4.4 ± 0.1 μm. The polar filament is wound in 20 to 23 helical coils. Although the parasite resembles T. pectinatellae described from the same host in Michigan and Ohio, it differs in the length of the spore and number of coils of the polar filament. Analysis of 16S rDNA by maximum likelihood, parsimony and Baysian inference, complements the morphological data in supporting the placement of T. algonquinensis as a sister species of T. pectinatellae.
The Microtubule Analog Protein, FtsZ, in the Endosymbiont of Trypanosomatid Protozoa
Authors: MOTTA MARIA CRISTINA M. , PICCHI GISELE FERNANDA A. , PALMIÉ‐PEKOTO ISABELLA V. , ROCHA MARCIA R. , DE CARVALHO TÉCIA MARIA U. , MORGADO‐DIAZ JOSE , DE SOUZA WANDERLEY , GOLDENBERG SAMUEL , FRAGOSO STENIO P.
Published: July 2005

Blastocrithidia culicis and Crithidia deanei are trypanosomatids that harbor an endosymbiotic bacterium in their cytoplasm. In prokaryotes, numerous proteins are essential for cell division, such as FtsZ, which is encoded by filament‐forming temperaturesensitive (fts) genes. FtsZ is the prokaryotic homolog of eukaryotic tubulin and is present in bacteria and archaea, and has also been identified in mitochondria and chloroplasts. FtsZ plays a key role in the initiation of cytokinesis. It selfassembles into the Z ring, which establishes the division plane during septation. In this study, immunoblotting analysis using a FtsZ polyclonal antibody, revealed a 40‐kDa band characteristic of FtsZ in endosymbiont fractions and in whole trypanosomatid homogenates, but not in whole cell extracts of aposymbiotic strains. Confocal microscopy and ultrastructural analysis revealed a specific and dispersed labeling over the endosymbiont. Bars and ring‐like structures, which are suggestive of the presence of Z‐rings, were never observed, even during the division of the symbiont. This peculiar distribution of FtsZ may represent an arrangement of cytoskeleton protein intermediate between prokaryotic and eukaryotic cells. The endosymbiont ftsz gene was completely sequenced after amplification of DNA from symbiont‐bearing trypanosomatids or from pure endosymbiont fractions, using PCR and specific primers. The sequences obtained from the endosymbionts from C. deanei and B. culicis were very similar, and were most closely related to bacteria from the genus Pseudomonas.
Ribosomal RNA Phylogeny of Bodonid and Diplonemid Flagellates and the Evolution of Euglenozoa
Authors: VON DER HEYDEN SOPHIE , CHAO EMA E. , VICKERMAN KEITH , CAVALIER‐SMITH THOMAS
Published: July 2005

Euglenozoa is a major phylum of excavate protozoa (comprising euglenoids, kinetoplastids, and diplonemids) with highly unusual nuclear, mitochondrial, and chloroplast genomes. To improve understanding of euglenozoan evolution, we sequenced nuclear small‐subunit rRNA genes from 34 bodonids (Bodo, Neobodo, Parabodo, Dimastigella‐like, Rhynchobodo, Rhynchomonas, and unidentified strains), nine diplonemids (Diplonema, Rhynchopus), and a euglenoid (Entosiphon). Phylogenetic analysis reveals that diplonemids and bodonids are more diverse than previously recognised, but does not clearly establish the branching order of kinetoplastids, euglenoids, and diplonemids. Rhynchopus is holophyletic; parasitic species arose from within free‐living species. Kinetoplastea (bodonids and trypanosomatids) are robustly holophyletic and comprise a major clade including all trypanosomatids and most bodonids (‘core bodonids’) and a very divergent minor one including Ichthyobodo. The root of the major kinetoplastid clade is probably between trypanosomatids and core bodonids. Core bodonids have three distinct subclades. Clade 1 has two distinct Rhynchobodo‐like lineages; a lineage comprising Dimastigella and Rhynchomonas; and another including Cruzella and Neobodo. Clade 2 comprises Cryptobial Trypanoplasma, Procryptobia, and Parabodo. Clade 3 is an extensive Bodo saltans species complex. Neobodo designis is a vast genetically divergent species complex with mutually exclusive marine and freshwater subclades. Our analysis supports three phagotrophic euglenoid orders: Petalomonadida (holophyletic), Ploeotiida (probably holophyletic), Peranemida (paraphyletic).
Identification and Assignment of Function to the Genes of Aspergillus fumigatus Expressed at 37 °C
Authors: SHANKAR JATA , NIGAM SHAILLY , SAXENA SHWETA , MADAN TARUNA , SARMA P. USHA
Published: July 2005

Aspergillus fumigatus, a fungal pathogen, causes a spectrum of allergic and invasive disorders. In order to rapidly identify genes of this fungus relevant for pathogenesis and as potential antifungal drug targets, 125 expressed sequence tags (ESTs) were generated from 200 phage clones of a non‐normalized cDNA library. Out of a novel 68 ESTs, 45 were assigned putative functions based on the sequence similarity. The identities of some of these genes suggest that they may be involved in pathogenesis or autoimmune reactions. Additional genes were identified that are possible targets for the development of antifungal drugs or that may be of use in diagnosing fungal infections.
Molecular Phylogeny of Phyllopharyngean Ciliates and their Group I Introns
Authors: SNOEYENBOS‐WEST OONA L. O. , COLE JEFFREY , CAMPBELL ANNA , COATS D. WAYNE , KATZ LAURA A.
Published: July 2005

We analyzed small subunit ribosomal DNA (ssu‐rDNA) sequences to evaluate both the monophyly of the ciliate class Phyllopharyngea de Puytorac et al. (1974), and relationships among subclasses. Classifications based on morphology and ultrastructure divide the Phyllopharyngea into four subclasses, the Phyllopharyngia, Chonotrichia, Rhynchodia, and Suctoria. Our analyses of ssu‐rDNA genealogies derived from sequence data collected from diverse members representing three of the four subclasses of Phyllopharyngea (Suctoria: Ephelota spp., Prodiscophyra collini, Acineta sp.; Phyllopharyngia: Chlamydodon exocellatus, Chlamydodon triquetrus, Dysteria sp.; and Chonotrichia: Isochona sp.) provide strong support for the monophyly of the Phyllopharyngea, and show that the Chonotrichia emerge from within the Phyllopharyngia. Based on this initial sampling, suctorian budding types are monophyletic, and exogenous budding appears to be basal to evaginative and endogenous budding. Further, we report the discovery of a group I intron at position 891 in the Suctoria Acineta sp. and Tokophrya lemnarum, and a second group I intron at position 1506 in T. lemnarum. These introns represent only the second examples of group I introns in a ciliate ribosomal gene, since the discovery of ribozymes in the LSU rRNA gene of Tetrahymena thermophila. Phylogenetic analyses of Group I introns suggest a complex evolutionary history involving either multiple loses or gains of introns within endogenously budding Suctoria.
Strombidinopsis jeokjo n. sp. (Ciliophora: Choreotrichida) from the Coastal Waters off Western Korea: Morphology and Small Subunit Ribosomal DNA Gene Sequence
Authors: JEONG HAE JIN , KIM JAE SEONG , KIM SANGHEE , SONG JAE YOON , LEE ILHA , LEE GEON‐HYOUNG
Published: July 2005

The planktonic ciliate Strombidinopsis jeokjo n. sp. is described from Quantitative Protargol‐Stained (QPS) preparations, and the sequence of the small subunit rDNA (SSU rDNA) from cultured cells is reported. This species is ovoid and bluntly tapered towards the posterior. The ranges (and mean ± standard deviation, n = 31) of cell length, cell width, and oral diameter of the QPS‐stained specimens were 100–190 μm (149 ± 25), 60–105 μm (79 ± 13), and 55–80 μm (64 ± 5), respectively. Fifteen to seventeen external oral polykinetids had oral membranelle cilia 20–35 μm long. Twenty‐six to twenty‐eight somatic kineties were equally spaced around the cell body and extended from the oral to the posterior regions with 23–44 dikinetids per kinety. Both kinetosomes of each kinetid bore cilia 3–7 μm long. Strombidinopsis jeokjo had two ovoid macronuclei of 25–38 μm × 12–15 μm. When properly aligned, the sequence of the SSU rDNA of S. jeokjo (GenBank Accession No. AJ628250) was approximately 2% different from that of an unidentified Strombidinopsis species (GenBank Accession No. AF399132‐AF399135), the closest species in the SSU rDNA sequence.
Predicted Secondary Structure of the Foraminiferal SSU 3′ Major Domain Reveals a Molecular Synapomorphy for Granuloreticulosean Protists
Authors: HABURA ANDREA , ROSEN DANIEL R. , BOWSER SAMUEL S.
Published: July 2005

The small subunit ribosomal RNA genes of foraminiferal protists are the largest and most divergent of any eukaryote. We demonstrate that this foraminiferal sequence alteration represents a substantial modification to the small subunit ribosomal RNA structure, including a large (up to 350 nt) novel helix in a very well‐conserved portion of the head domain. This modification dates from the beginning of the foraminiferal radiation and, within modern orders, is partially conserved at the sequence level, suggesting that it is a functional part of the ribosome. The pattern of conservation makes it particularly useful for determining lower‐taxon relationships in morphologically ambiguous allogromiid foraminifera.
Differential Stimulation of Microglial Pro‐Inflammatory Cytokines by Acanthamoeba culbertsoni versus Acanthamoeba castellanii
Authors: MARCIANO‐CABRAL FRANCINE , LUDWICK CHRISTINA , PUFFENBARGER ROBYN A. , CABRAL GUY A.
Published: July 2005

Acanthamoeba spp. are opportunistic pathogens that cause granulomatous amebic encephalitis. We compared the highly pathogenic species A. culbertsoni to the relatively less pathogenic species A. castellanii for its capacity to elicit from neonatal rat microglia the gene expression of pro‐inflammatory cytokines. Acanthamoeba culbertsoni elicited a robust cytokine gene response by neonatal rat microglia in vitro as compared to A. castellanii. The preponderant cytokine elicited at the mRNA and protein levels was interleukin‐1β. In addition, transmission electron microscopy revealed that microglial cells were capable of phagocytozing A. castellanii. In contrast, A. culbertsoni destroyed microglia. Collectively, these results suggest that a combined action of pro‐inflammatory cytokines and destruction of host cells by amebae contribute to the pathology caused by the more pathogenic species.
Vertical Micro‐Distribution and Response to Nitrogen Deposition of Testate Amoebae in Sphagnum
Authors: MITCHELL EDWARD A. D. , GILBERT DANIEL
Published: July 2005

Previous studies have shown the existence of a vertical micro‐distribution of testate amoebae in the first centimeters of Sphagnum and their response to nutrient enrichment. In order to test the response of testate amoebae to depth and N addition in dry moss carpets recolonizing cutover peatlands, we sampled Sphagnum that had received 0, 1, 3, or 10g N m−2 yr1 for three years. The mosses were cut into three segments: 0–1cm, 1–3cm and 3–5cm and analyzed for testate amoebae. The overall diversity (22 taxa) was high considering the dryness of the site, but the species richness of individual samples was low (mean 6.6). The presence of several species characteristic of wetter conditions suggests that they have a broader tolerance than usually believed and/or have a high colonization potential. Species richness increased with depth. Assulina muscorum was most abundant in the top segment, while Phryganella acropodia, Heleopera rosea and Nebela militaris were most abundant in the deepest segment. Neither the metabolism type nor the shell characteristics significantly explained the vertical distribution of species. There was no overall response of testate amoebae to N, although one species, Bullinularia indica, was significantly more abundant in the fertilized than in the control plots.
Viral Control of Phytoplankton Populations—a Review1
Authors: BRUSSAARD CORINA P. D.
Published: July 2005

ABSTRACT. Phytoplankton population dynamics are the result of imbalances between reproduction and losses. Losses include grazing, sinking, and natural mortality. As the importance of microbes in aquatic ecology has been recognized, so has the potential significance of viruses as mortality agents for phytoplankton. The field of algal virus ecology is steadily changing and advancing as new viruses are isolated and new methods are developed for quantifying the impact of viruses on phytoplankton dynamics and diversity. With this development, evidence is accumulating that viruses can control phytoplankton dynamics through reduction of host populations, or by preventing algal host populations from reaching high levels. The identification of highly specific host ranges of viruses is changing our understanding of population dynamics. Viral‐mediated mortality may not only affect algal species succession, but may also affect intraspecies succession. Through cellular lysis, viruses indirectly affect the fluxes of energy, nutrients, and organic matter, especially during algal bloom events when biomass is high. Although the importance of viruses is presently recognized, it is apparent that many aspects of viral‐mediated mortality of phytoplankton are still poorly understood. It is imperative that future research addresses the mechanisms that regulate virus infectivity, host resistance, genotype richness, abundance, and the fate of viruses over time and space.
Algicidal Bacteria in the Sea and their Impact on Algal Blooms1
Authors: MAYALI XAVIER , AZAM FAROOQ
Published: July 2005

ABSTRACT. Over the past two decades, many reports have revealed the existence of bacteria capable of killing phytoplankton. These algicidal bacteria sometimes increase in abundance concurrently with the decline of algal blooms, suggesting that they may affect algal bloom dynamics. Here, we synthesize the existing knowledge on algicidal bacteria interactions with marine eukaryotic microalgae. We discuss the effectiveness of the current methods to characterize the algicidal phenotype in an ecosystem context. We briefly consider the literature on the phylogenetic identification of algicidal bacteria, their interaction with their algal prey, the characterization of algicidal molecules, and the enumeration of algicidal bacteria during algal blooms. We conclude that, due to limitations of current methods, the evidence for algicidal bacteria causing algal bloom decline is circumstantial. New methods and an ecosystem approach are needed to test hypotheses on the impact of algicidal bacteria in algal bloom dynamics. This will require enlarging the scope of inquiry from its current focus on the potential utility of algicidal bacteria in the control of harmful algal blooms. We suggest conceptualizing bacterial algicidy within the general problem of bacterial regulation of algal community structure in the ocean.
Interactions between Planktonic Microalgae and Protozoan Grazers1
Authors: TILLMANN URBAN
Published: July 2005

ABSTRACT. For an algal bloom to develop, the growth rate of the bloom‐forming species must exceed the sum of all loss processes. Among these loss processes, grazing is generally believed to be one of the more important factors. Based on numerous field studies, it is now recognized that microzooplankton are dominant consumers of phytoplankton in both open ocean and coastal waters. Heterotrophic protists, a major component of microzooplankton communities, constitute a vast complex of diverse feeding strategies and behavior which allow them access to even the larger phytoplankton species. A number of laboratory studies have shown the capability of different protistan species to feed and grow on bloom‐forming algal species. Because of short generation times, their ability for fast reaction to short‐term variation in food conditions enables phagotrophic protists to fulfill the function of a heterotrophic buffer, which might balance the flow of matter in case of phytoplankton blooms. The importance of grazing as a control of microalgae becomes most apparent by its failure; if community grazing controls initial stages of bloom development, there simply is no bloom. However, if a certain algal species is difficult to graze, e.g. due to specific defense mechanisms, reduced grazing pressure will certainly favor bloom development. The present contribution will provide a general overview on the interactions between planktonic microalgae and protozoan grazers with special emphasis on species‐specific interactions and algal defense strategies against protozoan grazers.
Controlling Harmful Algal Blooms Through Clay Flocculation1
Authors: SENGCO MARIO R. , ANDERSON DONALD M.
Published: July 2005

ABSTRACT. The potential use of clays to control harmful algal blooms (HABs) has been explored in East Asia, Australia, the United States, and Sweden. In Japan and South Korea, minerals such as montmorillonite, kaolinite, and yellow loess, have already been used in the field effectively, to protect fish mariculture from Cochlodinium spp. and other blooms. Cell removal occurs through the flocculation of algal and mineral particles, leading to the formation of larger aggregates (i.e. marine snow), which rapidly settle and further entrain cells during their descent. In the U.S., several clays and clay‐rich sediments have shown high removal abilities (e.g. > 80% cell removal efficiency) against Karenia brevis, Heterosigma akashiwo, Pfiesteria piscicida and Aureococcus anophagefferens. In some cases, the removal ability of certain clays was further enhanced with chemical fiocculants, such as polyalummum chloride (PAC), to increase their adhesiveness. However, cell removal was also affected by bloom concentration, salinity, and mixing. Cell mortality was observed after clay addition, and increased with increasing clay concentration, and prolonged exposure to clays in the settled layer. Mesocosm, field enclosure, and flume experiments were also conducted to address cell removal with increasing scale and flow, water‐column impacts, and the possible benthic effects from clay addition. Results from these studies will be presented, especially those in regards to water quality, seawater chemistry, bottom credibility and faunal impacts in the benthos. At this time, clay dispersal continues to be a promising method for controlling HABs and mitigating their impacts based on existing information and experimental data.
Unexpected Foraminiferal Diversity Revealed by Small‐subunit rDNA Analysis of Antarctic Sediment
Authors: HABURA ANDREA , PAWLOWSKI JAN , HANES STEVEN D. , BOWSER SAMUEL S.
Published: July 2005

ABSTRACT. Studies of benthic Foraminifera typically rely on the morphological identification of dried specimens. This approach can introduce sampling bias against small, delicate, or morphologically ambiguous forms. To overcome this limitation, we extracted total DNA from sediment followed by PCR using group‐ and species‐specific primers. Phylogenetic analyses revealed that approximately ninety percent of the PCR products represented previously undescribed sequence types that group with undersampled members of the allogromiid Foraminifera. We also used a modification of this technique to track individual species in sediment fractions too fine for normal morphological identification, and to confirm species placement of morphologically ambiguous foraminiferans. We were able to identify the DNA of several large foraminiferal species in fine fractions in a seasonally‐dependent manner, indicating that in some seasons the majority of the standing stock of these species exists as gametes/juveniles. The approach outlined here represents a powerful strategy for exploring the total diversity of benthic foraminiferal communities.
Phylogenetic Relationships of the Subclass Peritrichia (Oligohymenophorea, Ciliophora) Inferred from Small Subunit rRNA Gene Sequences1
Authors: MIAO WEI , FEN WEI‐SONG , YU YU‐HE , ZHANG XI‐YUAN , SHEN YUN‐FEN
Published: July 2005

ABSTRACT. The phylogenetic relationships among peritrichs remain unresolved. In this study, the complete small subunit rRNA (SSrRNA) gene sequences of seven species (Epistylis galea, Campanella umbellaria, Carchesium polypinum, Zoothamnium arbuscula, Vaginicola crystallina, Ophrydium versatile, and Opercularia microdiscum) were determined. Trees were constructed using distancematrix, maximum‐likelihood and maximum‐parsimony methods, all of which strongly supported the monophyly of the subclass Peritrichia. Within the peritrichs, 1) E. galea grouped with Opercularia microdiscum and Campanella umbellaria but not the other Epistylis species, which indicates that the genus Epistylis might not be monophyletic; 2) the topological position of Carchesium and Campanella suggested that Carchesium should be placed in the family Zoothamniidae, or be elevated to a higher taxonomic rank, and that Campanella should be independent of the family Epistylididae, and probably be given a new rank; and 3) Opisthonecta grouped strongly with Astylozoon, which suggested that Opisthonecta species were not the ancestors of the stalked peritrichs.
Comparative Effectiveness of Light‐Microscopic Techniques and PCR in Detecting Thelohania solenopsae (Microsporidia) Infections in Red Imported Fire Ants (Solenopsis invicta)
Authors: MILKS MAYNARD L. , SOKOLOVA YULIYA Y. , ISAKOVA IRINA A. , FUXA JAMES R. , MITCHELL FORREST , SNOWDEN KAREN F. , VINSON S. BRADLEIGH
Published: July 2005

ABSTRACT. The main goal of this study was to compare the effectiveness of three staining techniques (calcofluor white M2R, Giemsa and modified trichrome), and the polymerase chain reaction (PCR) in detecting the microsporidium Thelohania solenopsae in red imported fire ants (Solenopsis invicta). The effect of the number of ants in a sample on the sensitivity of the staining techniques and the PCR, and the effect of three DNA extraction protocols on the sensitivity of PCR were also examined. In the first protocol, the ants were macerated and the crude homogenate was used immediately in the PCR. In the second protocol, the homogenate was placed on a special membrane (FTA card) that traps DNA, which is subsequently used in the PCR. In the third protocol, the DNA was purified from the homogenate by traditional phenol‐chloroform extraction. Except for PCR using FTA cards, the sensitivity (number of samples positive for T. solenopsae) of all detection techniques increased with the number of ants in the sample. Overall, Giemsa was the least sensitive of all detection techniques. Calcofluor was more sensitive than modified trichrome with ants from one site and was equally as sensitive as PCR with crude DNA or a FTA card with ants from both sites. Trichrome staining was equally as sensitive as PCR with a FTA card at both sites, but it was less sensitive than PCR with crude DNA at one site. PCR on FTA cards was less sensitive than PCR with crude DNA for ants from one site but not the other. There was no difference whether crude or phenol‐chloroform purified DNA was used as template.

In summary, the results of this study show that PCR based on a crude DNA solution is equal to or more sensitive in detecting T. solenopsae than the other detection techniques investigated, and that it can be used as a reliable diagnostic tool for screening field samples of S. invicta for T. solenopsae. Nevertheless, ant smear stained with calcofluor or modified trichrome should be used to buttress findings from PCR.
Molecular and Physiological Evaluation of Subtropical Environmental Isolates of Acanthamoeba spp., Causal Agent of Acanthamoeba Keratitis
Authors: BOOTON GREGORY C. , ROGERSON ANDREW , BONILLA TONYA D. , SEAL DAVID V. , KELLY DARYL J. , BEATTIE TARA K. , TOMLINSON ALAN , LARES‐VILLA FERNANDO , FUERST PAUL A. , BYERS THOMAS J.
Published: July 2005

ABSTRACT. Previous molecular examination of Acanthamoeba spp. has resulted in the determination of distinct genotypes in this genus (designated T1‐T12, T14). Genotype T4 has been responsible for the majority of cases of Acanthamoeba keratitis. Here we examine the relative abundance of environmental T4 isolates on beaches and ask whether they have temperature and salinity tolerances that could enhance pathogenicity. Twenty‐four Acanthamoeba strains were isolated from beach sand (n = 20), soil (n = 3), and tap water (n = 1) in south Florida. Phylogenetic analysis identified 19 of 24 isolates as T4, the Acanthamoeba keratitis‐associated genotype. The remaining isolates were genotype T5 (4) and T11 (1). Nearly all beach isolates were genotype T4, whereas the tap water and soil isolates were mostly T5. All amoebae grew at 0, 1.0, and 2.0% salt and 19 of 20 beach isolates also grew at 3.2%. No soil or tap‐water acanthamoebae reproduced at 3.2%. All isolates grew at 37 °C and two (T5) at 42 °C. Little correlation existed between beach location, salt‐tolerance, and genetic relatedness. Overall, the large majority of environmental isolates obtained were genotype T4, suggesting it may be the most common genotype in this environment and could be a potential source of Acanthamoeba keratitis infections.
The Epiplasm Gene EPC1 Influences Cell Shape and Cortical Pattern in Tetrahymena thermophila1
Authors: WILLIAMS NORMAN E.
Published: July 2005

ABSTRACT. The cortical protein Epclp is the most abundant protein in the membrane skeleton, or epiplasm, of Tetrahymena thermophila. A partial sequence of the EPC1 gene was obtained and used to obtain a knockout construct that was successful in transforming Tetrahymena thermophila cells. The results support the conclusion that Epclp influences cell shape and the fidelity of cortical development. It was further observed that this protein is transferred from plus to minus cells during conjugation, and that the imported protein is assembled into the epiplasm of the recipient cell in a discreet series of steps.
Transfer of Nosema locustae (Microsporidia) to Antonospora locustae n. comb. Based on Molecular and Ultrastructural Data1
Authors: SLAMOVITS CLAUDIO H. , WILLIAMS BRYONY A. P. , KEELING PATRICK J.
Published: July 2005

ABSTRACT. Nosema locustae is a microsporidian parasite of grasshopper pesthd that is used as a biological control agent, and is one of the emerging model systems for microsporidia. Due largely to its diplokaryotic nuclei, N. locustae has been classified in the genus Nosema, a large genus with members that infect a wide variety of insects. However, some molecular studies have cast doubt on the validity of certain Nosema species, and on the taxonomic position of N. locustae. To clarify the affinities of this important insect parasite we sequenced part of the rRNA operon of N. locustae and conducted a phylogenetic analysis using the complete small subunit rRNA gene. Nosema locustae is only distantly related to the nominotypic N. bombycis, and is instead closely related to Antonospora scoticae, a recently described parasite of bees. We examined the ultrastructure of mature N. locustae spores, and found the spore wall to differ from true Nosema species in having a multi‐layered exospore resembling that of Antonospora (one of the distinguishing features of that genus). Based on both molecular and morphological evidence, therefore, we propose transferring N. locustae to the genus Antonospora, as Antonospora locustae n. comb.
Nematopsis gigas n. sp. (Apicomplexa), a Parasite of Nerita ascencionis (Gastropoda, Neritidae) from Brazil
Authors: AZEVEDO CARLOS , PADOVAN ISAÍRAS
Published: July 2005

ABSTRACT. A new species of Nematopsis (Apicomplexa, Porosporidae) is described from the mantle tissues of the seawater gastropod, Nerita ascencionis (Neritidae), collected in the Atlantic North off the coast of “Fernando de Noronha” Island (3° 47′ 57″ S, 32° 25′ 12″ W) situated about 350 km from the northeast coast of Brazil. Numerous oocysts, each contained in a parasitophorous vacuole, were found in the cytoplasm of phagocytes in the mantle tissue of the host. The phagocytes were surrounded by a thin wall composed of lucent material. The phagocyte cytoplasm contained a nucleus surrounded by numerous vesicles and some dense masses. The oocysts were 21.9 ± 0.5 μm long, and 11.5 ± 0.6 μm wide. The oocyst wall was 0.18–0.25 μm thick, and the apical zone contained a micropyle, 1.0–1.2 μm in diameter, covered by a canopy‐like operculum about 0.25 μm thick. Externally, the oocyst wall was surrounded by numerous anastomosing microfibrils attached to the wall and extending towards the periphery of the parasitophorous vacuole. Some microfibrils formed a dense complex network that surrounded the oocyst in the middle of the parasitophorous vacuole, which opened only at the apical zone near the external region of the opercular system.

On the basis of the data obtained by light and transmission electron microscopy and host specificity, the gregarine Nematopsis gigas is distinguished from the nearest species as a new species. The taxonomic affinities and morphological comparisons with other similar species of the same genus are discussed.
The Ultrastructure of the Cyst Wall of Giardia lamblia
Authors: CHÁVEZ‐MUNGUÍA BIBIANA , CEDILLO‐RIVERA ROBERTO , MARTÍNEZ‐PALOMO ADOLFO
Published: July 2005

ABSTRACT. Giardiasis is the most common human protozoal infection. In then: cystic phase, giardias are protected from the environment by a filamentous cyst wall made up of carbohydrates, proteins, and by two outer membranes separated from the plasma membrane of the parasite by a peripheral space. The present transmission electron microscope observations of G. lamblia cysts of human origin suggest that the extracellular peritrophic space originates from the growth, elongation, and fusion of large cytoplasmic vacuoles. As the large clear vacuoles grew in size, flattening against the inner face of the plasma membrane, they formed a single vacuole that surrounded the body of the parasite, eventually forming two outer membranes. In mature Giardia cysts, the original plasma membrane of the trophozoite becomes the outermost membrane of the cyst wall (CM1). The large vacuoles form a second membrane surrounding the cyst (CM2), and also form a third membrane (CM3), that becomes the new plasma membrane of the trophozoite. During excystation CM1 and CM2 attach to each other and fragment, leaving abundant membrane residues in the peritrophic space. Knowledge of the biochemical composition and functional properties of the complex outer membranous system of G. lamblia cysts here described will be of use to understand the survival of Giardia cysts in the environment, a major factor responsible for the high prevalence of giardiasis worldwide.
Highly Divergent Actins from Karyorelictean, Heterotrich, and Litostome Ciliates1
Authors: KIM OANH T. P. , YURA KEI , GO NOBUHIRO , HARUMOTO TERUE
Published: July 2005

ABSTRACT. We have cloned, sequenced, and characterized cDNA of actins from five ciliate species of three different classes of the phylum Ciliophora: Karyorelictea (Loxodes striatus), Heterotrichea (Blepharisma japonicum, Blepharisma musculus), and Litostomatea (Didinium nasutum, Dileptus margaritifer). Loxodes striatus uses UGA as the stop codon and has numerous in‐frame UAA and UAG, which are translated into glutamine. The other four species use UAA as the stop codon and have no in‐frame UAG nor UGA. The putative amino acid sequences of the newly determined actin genes were found to be highly divergent as expected from previous findings of other ciliate actins. These sequences were also highly divergent from other ciliate actins, indicating that actin genes are highly diverse even within the phylum Ciliophora. Phylogenetic analysis showed high evolutionary rate of ciliate actins. Our results suggest that the evolutionary rate was accelerated because of the differences in molecular interactions.
Identification of a Second rRNA Gene Unit in the Perkinsus andrewsi Genome
Authors: PECHER WOLF T. , ROBLEDO JOSÉ A. F. , VASTA GERARDO R.
Published: July 2005

ABSTRACT. Perkinsus species are parasitic protozoa of mollusks, currently classified within the Perkinsozoa, a recently established phylum that is basal to the Apicomplexa and Dinozoa. Ribosomal RNA (rRNA) genes and their intergenic spacers have been used to support the taxonomy of Perkinsus species, the description of new species, and to develop molecular probes for their detection and identification. We previously described ultrastructure, behavior in culture, and partial sequence of the rRNA locus of a Perkinsus species isolated from the baltic clam Macoma balthica. The rRNA genes and intergenic spacers of this Perkinsus isolate differed from those described in the currently accepted species to a degree that led to its designation as a new species, Perkinsus andrewsi. In this study, we identify an additional rRNA gene unit (rRNA‐B) in the P. andrewsi holotype, and report the complete sequences of both rRNA gene units. Except for the 5. 8S, all regions of the rRNA‐B gene unit exhibited sequence differences from that initially described (rRNA‐A). Each rRNA gene unit is arranged in a “head‐to‐tail” tandem repeat. This is the first report demonstrating two distinct rRNA units in a Perkinsus species.
Ellobiopsids of the Genus Thalassomyces are Alveolates
Authors: SILBERMAN JEFFREY D. , COLLINS ALLEN G. , GERSHWIN LISA‐ANN , JOHNSON PATRICIA J. , ROGER ANDREW J.
Published: July 2005

ABSTRACT. Ellobiopsids are multinucleate protist parasites of aquatic crustaceans that possess a nutrient absorbing ‘root’ inside the host and reproductive structures that protrude through the carapace. Ellobiopsids have variously been affiliated with fungi, ‘colorless algae’, and dinoflagellates, although no morphological character has been identified that definitively alh'es them with any particular eukaryotic lineage. The arrangement of the trailing and circumferential flagella of the rarely observed bi‐flagellated ‘zoospore’ is reminiscent of dinoflagellate flagellation, but a well‐organized ‘dinokaryotic nucleus’ has never been observed. Using small subunit ribosomal RNA gene sequences from two species of Thalassomyces, phylogenetic analyses robustly place these ellobiopsid species among the alveolates (ciliates, apicomplexans, dinoflagellates and relatives) though without a clear affiliation to any established alveolate lineage. Our trees demonstrate that Thalassomyces fall within a dinoflagellate + apicomplexa + Perkinsidae +“marine alveolate group 1” clade, clustering most closely with dinoflagellates. However, the poor statistical support for branches within this region indicates that additional data will be needed to resolve relationships among these taxa.
Localization by Indirect Immunofluorescence of Tetrin, Actin, and Centrin to the Oral Apparatus and Buccal Cavity of the Macrostomal Form of Tetrahymena vorax
Authors: McLAUGHLIN NEIL B. , BUHSE HOWARD E.
Published: July 2005

ABSTRACT. We have taken advantage of the size of the macrostomal oral apparatus of Tetrahymena vorax to investigate the immunofluorescent localization of three cytoskeletal proteins—tetrin, actin, and centrin. Tetrin and actin antibodies co‐localize to cross‐connectives that anchor the membranelles. These antibodies also recognize the coarse filamentous reticulum, a filament associated with the undulating membrane. Actin‐specific localization extends beyond the coarse filamentous reticulum‐undulating membrane complex into a region called the specialized cytoplasm. A centrin antibody localizes to the fine filamentous reticulum which, along with micro‐tubules of the oral ribs, circumscribes the cytostomal opening. Models of phagocytic contraction based on these data are presented.
Morphologic and Genetic Variability in the Marine Planktonic Ciliate Laboea strobila Lohmann, 1908 (Ciliophora, Oligotrichia), with Notes on its Ontogenesis
Authors: AGATHA SABINE , STRÜDER‐KYPKE MICHAELA C. , BERAN ALFRED
Published: July 2005

ABSTRACT. Laboea strobila
Lohmann, 1908 is a conspicuous oligotrich ciliate in the marine plankton. In order to compare different populations, the morphology of specimens from the Mediterranean Sea, North Sea, and Irish Sea was investigated using live observation, protargol impregnation, and scanning electron microscopy. Furthermore, the PCR‐amplified products of the SSrRNA gene from a monoclonal culture of L. strobila from the Mediterranean Sea were sequenced and aligned with sequences of other oligotrichs, including a population of L. strobila from the Atlantic coast of the USA. Finally, the data from the ecological literature were summarized and the cultivation methods were described. The SSrRNA gene sequences of the two distantly located L. strobila populations from the North Atlantic are identical. Likewise, the morphometrics of most populations so far investigated after protargol impregnation (i.e. from the North Atlantic) do not show obvious differences. In all computed phylogenetic trees, L. strobila groups with Strombidium species, forming a monophyletic taxon corresponding to the subclass Oligotrichia. These results are corroborated by the ontogenetic comparison. Since no type species was fixed for LaboeaLohmann, 1908, L. strobila was designated in the present paper.
Diversity of Insect Trypanosomatids Assessed from the Spliced Leader RNA and 5s rRNA Genes and Intergenic Regions1
Authors: PODLIPAEV SERGEI A. , STURM NANCY R. , FIALA IVAN , FERNANDES OCTAVIO , WESTENBERGER SCOTT J. , DOLLET MICHEL , CAMPBELL DAVID A. , LUKEŠ JULIUS
Published: July 2005

We have determined the sequences of 5S rRNA and spliced leader (SL) RNA genes, and adjacent intergenic regions for representatives of all known trypanosomatid genera parasitizing insects. The genetic loci have been analyzed separately as well as by a combined approach. Several isolates, assigned by morphology to different genera (Leptomonas spp., Blastocrithidia spp.), seem to belong to a single species with an unexpectedly wide host and geographical range. An unnamed trypanosomatid isolated from rats in Egypt was found to belong to the genus Herpetomonas, so far associated with insect hosts only. It is closely related to Herpetomonas ztiplika, a parasite of a blood‐sucking biting midge. Apparently several different trypanosomatid species can infect one insect species, as exemplified by Leptomonas sp. PL and Wallaceina sp. Wsd, which were isolated from different specimens of Salda littoralis on the same locality and day. However, since the same species of Leptomonas was obtained from insect hosts belonging to different genera, some insect trypanosomatids may have low host specificity. Our data revealed additional discrepancies between molecular phylogenetic data and cell morphology, rendering current trypanosomatid taxonomy unreliable.