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1

Phylum Tardigrada  

NSDL National Science Digital Library

This "Online Zoologists" web page features a technical description of the phylum Tardigrada. Written in an outline format, the page includes a definition of the phylum and discusses external features, internal features, reproduction, embryology, ecology and physiology, classification, phylogeny, and references.

Elsberry, Wesley R.

2009-07-01

2

Coccidia (Apicomplexa: Eimeriidae) in the Primates and the Scandentia  

Microsoft Academic Search

The coccidia (protistan phylum Apicomplexa Levine, 1970) comprise a large group of obligate intracellular parasites commonly found in all classes of vertebrate hosts and in some invertebrates. This review focuses on the largest family in this group, Eimeriidae Minchin, 1903, because its members are among the most prevalent and specious of all parasite groups. Nevertheless, there is a paucity of

Donald W. Duszynski; Wade D. Wilson; Steve J. Upton; Norman D. Levine

1999-01-01

3

Morphologic, immunohistochemical, and molecular characterization of a novel Lankesterella protozoan in two White's tree frogs (Litoria caerulea).  

PubMed

Two White's tree frogs (Litoria caerulea) housed at a zoological park died after a short period of lethargy, weight loss, and edema. Detailed postmortem examinations were performed on both frogs, including bacterial cultures and complete histologic examinations. Intracytoplasmatic as well as free protozoan parasites were identified in multiple organs from both frogs. The parasites were identified within erythrocytes, leukocytes, endothelial cells, and hepatocytes. Immunohistochemistry demonstrated a cross-reaction with Toxoplasma gondii antisera. Parasite ultrastructural analysis was performed by transmission electron microscopy. The parasites demonstrated an apical complex containing a conoid, rhoptries, and micronemes, demonstrating it was a member of the phylum Apicomplexa. In addition, the parasites had bipolar paranuclear bodies, organelles that are typical of coccidian sporozoites. The organisms were tentatively identified as members of the genus Lankesterella on the basis of histologic and ultrastructural morphology. A portion of the 18s ribosomal RNA (rRNA) gene was amplified via a polymerase chain reaction, sequenced, and used in a Basic Local Alignment Search Tool search of the GenBank database. The 18s rRNA gene sequence was found to be most similar to gene sequences isolated from Lankesterella organisms (88%). In aggregate, these data support the classification of these protozoa as a novel species of Lankesterella. A causal relationship between frog morbidity and protozoal parasitism was not determined. This is the first report of Lankesterella sp. in White's tree frogs. PMID:20597215

Gericota, Barbara; Garner, Michael M; Barr, Bradd; Nordhausen, Robert; Larsen, R Scott; Lowenstine, Linda J; Murphy, Brian G

2010-06-01

4

New Eukaryotic Systematics: A Phylogenetic Perspective of Developmental Gene Expression in the Apicomplexa  

PubMed Central

The phylum Apicomplexa consists of obligate intracellular protistan parasites, some of which are responsible for global disease causing serious morbidity and mortality in humans and animals. Understanding the mechanisms of gene expression that drive the cellular changes required to complete their life cycles will be critical in combating infection and disease. Plasmodium spp. and Toxoplasma gondii have served as good models for growth and development in the Apicomplexa. Elucidating developmental gene expression relies on comparisons to known mechanisms and their DNA, RNA and protein components. Transcriptional profiling across asexual development suggests a model where a cascade of gene expression results in a “just in time” production process that makes products only when needed. Some mechanisms that control transcription such as chromatin/histone modification are highly conserved in the phylum compared to the traditional model organisms, yeast, worms, flies and mammals. Studies exploiting this phenomenon show great potential for both investigating the effects of chromatin structure on developmental gene expression, and helping to identify genes that are expressed in stage-specific manner. Transcription factors and their cognate cis-acting binding sites have been difficult to identify. This may be because the DNA binding motifs that have evolved to act as transcription factors in the Apicomplexa, e.g. the AP2 family, may be more like plants than the traditional model organisms. A new eukaryotic phylogenetic model comprised of six supergroups divides the traditional model organisms, plants and the Apicomplexa into separate supergroups. This phylogenetic model helps explain why basic functions such as transcriptional regulation appear be a composite of mechanisms in the Apicomplexa compared to what is known from other eukaryotes.

Gissot, Mathieu; Kim, Kami; Schaap, Dick; Ajioka, James W.

2014-01-01

5

Phylum XVII. Acidobacteria phyl. nov  

Microsoft Academic Search

\\u000a The phylum currently contains two classes, three orders, three families, and six described genera. The phylum is identified\\u000a on the basis of phylogenetic analysis of 16S rRNA gene sequences (Figure 117).

J. Cameron Thrash; John D. Coates

6

First report of Calyptospora sp. (Apicomplexa, Calyptosporidae) in forage characid fish from the Três Marias Reservoir, São Francisco Basin, Brazil.  

PubMed

Coccidians are parasitic protozoans, and Calyptospora is an important genus of coccidia found in freshwater and marine fish of the Americas. This paper describes Calyptospora sp. that were found parasitizing the liver and intestine of Triportheus guentheri and the intestine of Tetragonopterus chalceus, two forage fish species from the Três Marias Reservoir, Upper São Francisco River, State of Minas Gerais, Brazil. Apicomplexa found in the São Francisco Basin are reported here for the first time. PMID:20163938

de Albuquerque, Marcia Cavalcanti; de Carvalho Brasil-Sato, Marilia

2010-05-01

7

Coloniality in the phylum Rotifera  

Microsoft Academic Search

Coloniality in the phylum Rotifera is defined and reviewed. Only two families of rotifers contain truly colonial forms: Flosculariidae and Conochilidae (order Gnesiotrocha, suborder Flosculariacea). Most species form intraspecific colonies ranging in size from a few to about 200 individuals, but species that produce enormous colonies (> 1000 individuals) are also known. All seven genera of the Flosculariidae contain species

Robert Lee Wallace

1987-01-01

8

TRAP Is Necessary for Gliding Motility and Infectivity of Plasmodium Sporozoites  

Microsoft Academic Search

Many protozoans of the phylum Apicomplexa are invasive parasites that exhibit a substrate-dependent gliding motility. Plasmodium (malaria) sporozoites, the stage of the parasite that invades the salivary glands of the mosquito vector and the liver of the vertebrate host, express a surface protein called thrombospondin-related anonymous protein (TRAP) that has homologs in other Apicomplexa. By gene targeting in a rodent

Ali A. Sultan; Vandana Thathy; Ute Frevert; Kathryn J. H. Robson; Andrea Crisanti; Victor Nussenzweig; Ruth S. Nussenzweig; Robert Ménard

1997-01-01

9

A transcriptomic analysis of the phylum Nematoda  

Microsoft Academic Search

The phylum Nematoda occupies a huge range of ecological niches, from free-living microbivores to human parasites. We analyzed the genomic biology of the phylum using 265,494 expressed-sequence tag sequences, corresponding to 93,645 putative genes, from 30 species, including 28 parasites. From 35% to 70% of each species' genes had significant similarity to proteins from the model nematode Caenorhabditis elegans. More

Makedonka Mitreva; Claire Whitton; Marian Thomson; Jennifer Daub; John Martin; Ralf Schmid; Neil Hall; Bart Barrell; Robert H Waterston; James P McCarter; Mark L Blaxter; John Parkinson

2004-01-01

10

Waterborne protozoan pathogens.  

PubMed Central

Protozoan parasites were the most frequently identified etiologic agents in waterborne disease outbreak from 1991 to 1994. The waterborne parasites Giardia lamblia, Naegleria fowleri, Acanthamoeba spp., Entamoeba histolytica, Cryptosporidium parvum, Cyclospora cayetanesis, Isospora belli, and the microsporidia are reviewed. For each parasite, the review includes history, life cycle, incidence, symptoms, and therapy. Clinical detection methods are compared, and emerging technologies are discussed. Information on the association of these parasites with waterborne outbreaks is reviewed. Current information on protozoan parasites identified as etiological agents in waterborne outbreaks is discussed. Water industry issues related to recent disease outbreaks are examined in the context of water quality testing regulations for G. lamblia and those proposed for C. parvum. The review identifies the limitations of the American Society of Testing and Materials water-testing method for these parasites. An overview of federal regulations affecting the water industry and laboratories that test for water quality is also provided. The article highlights the importance of the clinical laboratory as a frontline defense for the detection of infectious organisms. The review points to the need for clinical laboratories, physicians, and public health personnel to cooperatively plan and assess the challenge of meeting this potential public health threat.

Marshall, M M; Naumovitz, D; Ortega, Y; Sterling, C R

1997-01-01

11

Phylum Verrucomicrobia representatives share a compartmentalized cell plan with members of bacterial phylum Planctomycetes  

PubMed Central

Background The phylum Verrucomicrobia is a divergent phylum within domain Bacteria including members of the microbial communities of soil and fresh and marine waters; recently extremely acidophilic members from hot springs have been found to oxidize methane. At least one genus, Prosthecobacter, includes species with genes homologous to those encoding eukaryotic tubulins. A significant superphylum relationship of Verrucomicrobia with members of phylum Planctomycetes possessing a unique compartmentalized cell plan, and members of the phylum Chlamydiae including human pathogens with a complex intracellular life cycle, has been proposed. Based on the postulated superphylum relationship, we hypothesized that members of the two separate phyla Planctomycetes and Verrucomicrobia might share a similar ultrastructure plan differing from classical prokaryote organization. Results The ultrastructure of cells of four members of phylum Verrucomicrobia – Verrucomicrobium spinosum, Prosthecobacter dejongeii, Chthoniobacter flavus, and strain Ellin514 – was examined using electron microscopy incorporating high-pressure freezing and cryosubstitution. These four members of phylum Verrucomicrobia, representing 3 class-level subdivisions within the phylum, were found to possess a compartmentalized cell plan analogous to that found in phylum Planctomycetes. Like all planctomycetes investigated, they possess a major pirellulosome compartment containing a condensed nucleoid and ribosomes surrounded by an intracytoplasmic membrane (ICM), as well as a ribosome-free paryphoplasm compartment between the ICM and cytoplasmic membrane. Conclusion A unique compartmentalized cell plan so far found among Domain Bacteria only within phylum Planctomycetes, and challenging our concept of prokaryote cell plans, has now been found in a second phylum of the Domain Bacteria, in members of phylum Verrucomicrobia. The planctomycete cell plan thus occurs in at least two distinct phyla of the Bacteria, phyla which have been suggested from other evidence to be related phylogenetically in the proposed PVC (Planctomycetes-Verrucomicrobia-Chlamydiae) superphylum. This planctomycete cell plan is present in at least 3 of 6 subdivisions of Verrucomicrobia, suggesting that the common ancestor of the verrucomicrobial phylum was also compartmentalized and possessed such a plan. The presence of this compartmentalized cell plan in both phylum Planctomycetes and phylum Verrucomicrobia suggest that the last common ancestor of these phyla was also compartmentalized.

2009-01-01

12

Sterols of the phylum Zygomycota: Phylogenetic implications  

Microsoft Academic Search

The sterol composition of 42 fungal species representing six of the eight orders of the Zygomycota was determined using gas-liquid\\u000a chromatography-mass spectrometry to assess whether the distribution of major sterols in this phylum has taxonomic or phylogenetic\\u000a relevance. Ergosterol, 22-dihydroergosterol, 24-methyl cholesterol, cholesterol, and desmosterol were detected as the major\\u000a sterols among the species studied. Ergosterol was the major sterol

J. D. Weete; S. R. Gandhi

1997-01-01

13

Perkinsus sp. (Phylum Apicomplexa) in Mediterranean clam Ruditapes semidecussatus: ultrastructural observations of the cellular response of the host  

Microsoft Academic Search

An infection caused by a Perkinsus sp. was observed in Ruditapes semidecussatus collected on the western Mediterranean coast (Tarragona, Spain). The trophozoites were generally grouped and surrounded by amorphous material that constituted a nodule. These nodule reactions with trophozoites were located in connective tissue of the gut, hepatopancreas, kidney, gonads, mantle, and gill. Ultrastructural features of the host reaction due

E. Sagristá; M. Durfort; C. Azevedo

1995-01-01

14

Acidobacteria Phylum Sequences in Uranium-Contaminated Subsurface Sediments Greatly Expand the Known Diversity within the Phylum  

Microsoft Academic Search

The abundance and composition of bacteria of the phylum Acidobacteria were surveyed in subsurface sediments from uranium-contaminated sites using amplification of 16S rRNA genes followed by clone\\/sequence analysis. Analysis of sequences from this study and public databases produced a revised and greatly expanded phylogeny of the Acidobacteria phylum consisting of 26 subgroups. Bacteria in the Acidobacteria phylum have been detected

Susan M. Barns; Elizabeth C. Cain; Leslie Sommerville; Cheryl R. Kuske

2007-01-01

15

Phylogenetic relationships within phylum Rotifera: orders and genus Notholca  

Microsoft Academic Search

We investigated evolutionary relationships among orders in phylum Rotifera and among species in genus Notholca (Rotifera) by computing parsimonious cladograms. All of the most-parsimonious cladograms generated for the ordinal level confirm the view that class Monogononta, superclass Eurotatoria, and phylum Rotifera are monophyletic. Species within the genus Notholca were separated into six groups (clades), but some species have been defined

Robert Lee Wallace; Rebecca Arlene Colburn

1989-01-01

16

Photoacoustic spectroscopy of man infecting protozoans  

SciTech Connect

In this paper the fundamentals of photothermal spectroscopy are presented, special emphasis is done in the obtention of the optical absorption spectra. It is shown that this spectroscopy can be used successfully for the monitoring of protozoans that could infect the human. The usefulness of the technique is illustrated in the special case of Leishmania, where it is possible to find that the stage when the protozoan infect vertebrate cells show important differences in relation to the protozoans infecting insects.

Acosta-Avalos, D. [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, Barrio da Urca, CEP 22290-180, Rio de Janeiro (Brazil); Alvarado-Gil, J. J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Apartado Postal 73 Cordemex, Merida, Yucatan, 97310 (Mexico); Vargas, H. [Universidade Estadual do Norte Fluminense, CEP 28015-620, Rio de Janeiro (Brazil)

1998-08-28

17

Apoptotic markers in protozoan parasites.  

PubMed

The execution of the apoptotic death program in metazoans is characterized by a sequence of morphological and biochemical changes that include cell shrinkage, presentation of phosphatidylserine at the cell surface, mitochondrial alterations, chromatin condensation, nuclear fragmentation, membrane blebbing and the formation of apoptotic bodies. Methodologies for measuring apoptosis are based on these markers. Except for membrane blebbing and formation of apoptotic bodies, all other events have been observed in most protozoan parasites undergoing cell death. However, while techniques exist to detect these markers, they are often optimised for metazoan cells and therefore may not pick up subtle differences between the events occurring in unicellular organisms and multi-cellular organisms.In this review we discuss the markers most frequently used to analyze cell death in protozoan parasites, paying special attention to changes in cell morphology, mitochondrial activity, chromatin structure and plasma membrane structure/permeability. Regarding classical regulators/executors of apoptosis, we have reviewed the present knowledge of caspase-like and nuclease activities. PMID:21062457

Jiménez-Ruiz, Antonio; Alzate, Juan Fernando; Macleod, Ewan Thomas; Lüder, Carsten Günter Kurt; Fasel, Nicolas; Hurd, Hilary

2010-01-01

18

Apoptotic markers in protozoan parasites  

PubMed Central

The execution of the apoptotic death program in metazoans is characterized by a sequence of morphological and biochemical changes that include cell shrinkage, presentation of phosphatidylserine at the cell surface, mitochondrial alterations, chromatin condensation, nuclear fragmentation, membrane blebbing and the formation of apoptotic bodies. Methodologies for measuring apoptosis are based on these markers. Except for membrane blebbing and formation of apoptotic bodies, all other events have been observed in most protozoan parasites undergoing cell death. However, while techniques exist to detect these markers, they are often optimised for metazoan cells and therefore may not pick up subtle differences between the events occurring in unicellular organisms and multi-cellular organisms. In this review we discuss the markers most frequently used to analyze cell death in protozoan parasites, paying special attention to changes in cell morphology, mitochondrial activity, chromatin structure and plasma membrane structure/permeability. Regarding classical regulators/executors of apoptosis, we have reviewed the present knowledge of caspase-like and nuclease activities.

2010-01-01

19

Interferon effects on protozoan infections  

NASA Technical Reports Server (NTRS)

The effects of interferon (IFN) on mice infected with two different parasitic protozoans, Trypanosoma cruzi and Trypanosoma brucei rhodesiense, are investigated experimentally. The preparation of the cell cultures, IFN and assays, antibody, and the experimental procedures are described. It is observed that in cells treated with IFN-gamma there is an increased association of T. cruzi with murine macrophages and an increase in the killing of T. cruzi by IFN-gamma-treated murine macrophages. For spleen cells infected with T.b. rhodesiense in vitro, it is detected that live trypanosomes cannot induce IFN in cells from normal mice, but can in cells from immunized mice; and that trypanosome-lysates induce IFN in vitro in cells from normal mice. The data suggest that there is a two-step mechanism for mice against T. cruzi and T.b. rhodesiense.

Sonnenfeld, G.; Wirth, J.; Kierszenbaum, F.; Degee, A. L. W.; Mansfield, J. M.

1985-01-01

20

Detection of antibodies against Brucella abortus, Leptospira spp., and Apicomplexa protozoa in water buffaloes in the Northeast of Argentina.  

PubMed

Water buffalo industry has become a profitable activity worldwide, including the Northeast of Argentina (NEA). However, research on diseases affecting this species is scarce. The aim of the present study was to detect antibodies against Brucella abortus, Leptospira spp., Neospora caninum, Toxoplasma gondii, and Sarcocystis spp. in 500 water buffalo cows from five ranches (100 animals each) in the NEA. Serum samples were tested for B. abortus by fluorescence polarization assay, Leptospira spp. by microagglutination test, and N. caninum, T. gondii, and Sarcocystis spp. by indirect fluorescent antibody tests. Overall, the proportion of seropositive animals was 6.4, 22.2, 42.2, 25.4, and 50.8 % for brucellosis, leptospirosis, neosporosis, toxoplasmosis, and sarcocystosis, respectively. The proportion of seropositive animals for all diseases was statistically different among herds (p?Apicomplexa protozoans in water buffaloes in the NEA is reported in this study. PMID:23765549

Konrad, José L; Campero, Lucía M; Caspe, Gastón S; Brihuega, Bibiana; Draghi, Graciela; Moore, Dadin P; Crudeli, Gustavo A; Venturini, María C; Campero, Carlos M

2013-11-01

21

Nuclear-Encoded Proteins Target to the Plastid in Toxoplasma gondii and Plasmodium falciparum  

Microsoft Academic Search

A vestigial, nonphotosynthetic plastid has been identified recently in protozoan parasites of the phylum Apicomplexa. The apicomplexan plastid, or ``apicoplast,'' is indispensable, but the complete sequence of both the Plasmodium falciparum and Toxoplasma gondii apicoplast genomes has offered no clue as to what essential metabolic function(s) this organelle might perform in parasites. To investigate possible functions of the apicoplast, we

Ross F. Waller; Patrick J. Keeling; Robert G. K. Donald; Boris Striepen; Emanuela Handman; Naomi Lang-Unnasch; Alan F. Cowman; Gurdyal S. Besra; David S. Roos; Geoffrey I. McFadden

1998-01-01

22

Genome-scale protein expression and structural biology of Plasmodium falciparum and related Apicomplexan organisms  

Microsoft Academic Search

Parasites from the protozoan phylum Apicomplexa are responsible for diseases, such as malaria, toxoplasmosis and cryptosporidiosis, all of which have significantly higher rates of mortality and morbidity in economically underdeveloped regions of the world. Advances in vaccine development and drug discovery are urgently needed to control these diseases and can be facilitated by production of purified recombinant proteins from Apicomplexan

Masoud Vedadi; Jocelyne Lew; Jennifer Artz; Mehrnaz Amani; Yong Zhao; Aiping Dong; Gregory A. Wasney; Mian Gao; Tanya Hills; Stephen Brokx; Wei Qiu; Sujata Sharma; Angelina Diassiti; Zahoor Alam; Michelle Melone; Anne Mulichak; Amy Wernimont; James Bray; Peter Loppnau; Olga Plotnikova; Kate Newberry; Emayavaram Sundararajan; Simon Houston; John Walker; Wolfram Tempel; Alexey Bochkarev; Ivona Kozieradzki; Aled Edwards; Cheryl Arrowsmith; David Roos; Kevin Kain; Raymond Hui

2007-01-01

23

ESPÉCIES DO GÊNERO Eimeria (APICOMPLEXA: EIMERIIDAE) EM TAMANDUÁS-BANDEIRA (Myrmecophaga tridactyla LINNAEUS, 1758) EM CATIVEIRO  

Microsoft Academic Search

1 ABSTRACT:- FREITAS, F.L. DA C.; ALMEIDA, K. DE S.; ZANETTI, A.S.; NASCIMENTO, A.A. DO; MACHADO, C. R.; MACHADO, R.Z. (Species of the genus Eimeria (Apicomplexa: Eimeriidae) in giant anteaters (Myrmecophaga tridactyla Linnaeus, 1758) in captivity). Espécies do gênero Eimeria (Apicomplexa: Eimeriidae) em Tamanduás-bandeira (Myrmecophaga tridactyla Linnaeus, 1758) em cativeiro. Revista Brasileira de Parasitologia Veterinária, v. 15, n. 1, p.

FAGNER LUIZ DA C. FREITAS; ANDRÉ S. ZANETTI; CÉLIO R. MACHADO; ROSANGELA Z. MACHADO

24

Protozoan Vaccine Candidate Homologues in Tetrahymena thermophila  

Microsoft Academic Search

Tetrahymena thermophila is a member of the phylum Ciliophora (the ciliated protozoa) and is currently of great interest due to its unique qualities that make it useful as a model for research directed towards understanding how eukaryotic cells function. Recently, the T. thermophila genome was sequenced, and made available online. Since Tetrahymena is a member of the Alveolata, the major

Justin Schumacher

2009-01-01

25

Comparative Analysis of Apicomplexa and Genomic Diversity in Eukaryotes  

PubMed Central

The apicomplexans Plasmodium and Cryptosporidium have developed distinctive adaptations via lineage-specific gene loss and gene innovation in the process of diverging from a common parasitic ancestor. The two lineages have acquired distinct but overlapping sets of surface protein adhesion domains typical of animal proteins, but in no case do they share multidomain architectures identical to animals. Cryptosporidium, but not Plasmodium, possesses an animal-type O-linked glycosylation pathway, along with >30 predicted surface proteins having mucin-like segments. The two parasites have notable qualitative differences in conserved protein architectures associated with chromatin dynamics and transcription. Cryptosporidium shows considerable reduction in the number of introns and a concomitant loss of spliceosomal machinery components. We also describe additional molecular characteristics distinguishing Apicomplexa from other eukaryotes for which complete genome sequences are available.

Templeton, Thomas J.; Iyer, Lakshminarayan M.; Anantharaman, Vivek; Enomoto, Shinichiro; Abrahante, Juan E.; Subramanian, G.M.; Hoffman, Stephen L.; Abrahamsen, Mitchell S.; Aravind, L.

2004-01-01

26

INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)  

EPA Science Inventory

The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

27

Named species and hosts of Sarcocystis (Protozoa: Apicomplexa: Sarcocystidae)  

Microsoft Academic Search

Summary  A list is given of the present 93 species of the apicomplexan protozoan genus Sarcocystis together with their definitive and intermediate hosts (if known), synonyms, homonyms, lapsi calami, etc. The names of many species of this genus are poorly known, in doubt or controversial due to lack of access to some of the literature and to failure to accept the

Norman D. Levine; Wedad Tadros

1980-01-01

28

Culturing and Using Protozoans in the Laboratory.  

ERIC Educational Resources Information Center

Provides instructions for teachers and students to culture protozoans for use in science laboratories. Sections include setting up a culture area, basic culture media, amoeba culture technique, powdered milk-wheat-rice medium, alfalfa medium, and uses of the protozoa in the laboratory. (PR)

Hummer, Paul J., Jr.

1993-01-01

29

Protozoan Parasites and Pathological Findings in  

Microsoft Academic Search

Tissues from 23 Australian water rats (Hydromys chrysogaster) collected from five localities in central and northern Queens- land, Australia, between February 1992 and May 1993, were examined for protozoan para- sites and additional pathological changes. We found Kiossiella hydromyos in the kidneys, Toxoplasma gondii in the brain and skeletal miuuiscles and Sarcocystis sp. in the somatic mus- culatimre. Other pathological

Mount Pleasant Labo; Kings Meadows

1996-01-01

30

Validation and justification of the phylum name Cryptomycota phyl. nov.  

PubMed

The recently proposed new phylum name Cryptomycota phyl. nov. is validly published in order to facilitate its use in future discussions of the ecology, biology, and phylogenetic relationships of the constituent organisms. This name is preferred over the previously tentatively proposed "Rozellida" as new data suggest that the life-style and morphology of Rozella is not representative of the large radiation to which it and other Cryptomycota belong. Furthermore, taxa at higher ranks such as phylum are considered better not based on individual names of included genera, but rather on some special characteristics - in this case the cryptic nature of this group and that they were initially revealed by molecular methods rather than morphological discovery. If the group were later viewed as a member of a different kingdom, the name should be retained to indicate its fungal affinities, as is the practice for other fungal-like protist groups. PMID:22679602

Jones, Meredith D M; Richards, Thomas A; Hawksworth, David L; Bass, David

2011-12-01

31

An expanded genomic representation of the phylum cyanobacteria.  

PubMed

Molecular surveys of aphotic habitats have indicated the presence of major uncultured lineages phylogenetically classified as members of the Cyanobacteria. One of these lineages has recently been proposed as a nonphotosynthetic sister phylum to the Cyanobacteria, the Melainabacteria, based on recovery of population genomes from human gut and groundwater samples. Here, we expand the phylogenomic representation of the Melainabacteria through sequencing of six diverse population genomes from gut and bioreactor samples supporting the inference that this lineage is nonphotosynthetic, but not the assertion that they are strictly fermentative. We propose that the Melainabacteria is a class within the phylogenetically defined Cyanobacteria based on robust monophyly and shared ancestral traits with photosynthetic representatives. Our findings are consistent with theories that photosynthesis occurred late in the Cyanobacteria and involved extensive lateral gene transfer and extends the recognized functionality of members of this phylum. PMID:24709563

Soo, Rochelle M; Skennerton, Connor T; Sekiguchi, Yuji; Imelfort, Michael; Paech, Samuel J; Dennis, Paul G; Steen, Jason A; Parks, Donovan H; Tyson, Gene W; Hugenholtz, Philip

2014-05-01

32

An Expanded Genomic Representation of the Phylum Cyanobacteria  

PubMed Central

Molecular surveys of aphotic habitats have indicated the presence of major uncultured lineages phylogenetically classified as members of the Cyanobacteria. One of these lineages has recently been proposed as a nonphotosynthetic sister phylum to the Cyanobacteria, the Melainabacteria, based on recovery of population genomes from human gut and groundwater samples. Here, we expand the phylogenomic representation of the Melainabacteria through sequencing of six diverse population genomes from gut and bioreactor samples supporting the inference that this lineage is nonphotosynthetic, but not the assertion that they are strictly fermentative. We propose that the Melainabacteria is a class within the phylogenetically defined Cyanobacteria based on robust monophyly and shared ancestral traits with photosynthetic representatives. Our findings are consistent with theories that photosynthesis occurred late in the Cyanobacteria and involved extensive lateral gene transfer and extends the recognized functionality of members of this phylum.

Soo, Rochelle M.; Skennerton, Connor T.; Sekiguchi, Yuji; Imelfort, Michael; Paech, Samuel J.; Dennis, Paul G.; Steen, Jason A.; Parks, Donovan H.; Tyson, Gene W.; Hugenholtz, Philip

2014-01-01

33

Mobile genetic elements in the bacterial phylum Acidobacteria  

PubMed Central

Analysis of the genome of Candidatus Solibacter usitatus Ellin6076, a member of the phylum Acidobacteria, revealed a large number of genes associated with mobile genetic elements. These genes encoded transposases, insertion sequence elements and phage integrases. When the amino acid sequences of the mobile element-associated genes were compared, many of them had high (90–100%) amino acid sequence identities, suggesting that these genes may have recently duplicated and dispersed throughout the genome. Although phage integrase encoding genes were prevalent in the Can. S. usitatus Ellin6076 genome, no intact prophage regions were found. This suggests that the Can. S. usitatus Ellin6076 large genome arose by horizontal gene transfer via ancient bacteriophage and/or plasmid-mediated transduction, followed by widespread small-scale gene duplications, resulting in an increased number of paralogs encoding traits that could provide selective metabolic, defensive and regulatory advantages in the soil environment. Here we examine the mobile element repertoire of Can. S. usitatus Ellin6076 in comparison to other genomes from the Acidobacteria phylum, reviewing published studies and contributing some new analyses. We also discuss the presence and potential roles of mobile elements in members of this phylum that inhabit a variety of environments.

Challacombe, Jean; Kuske, Cheryl

2012-01-01

34

T Cell exhaustion in protozoan disease  

PubMed Central

Protozoan parasites cause severe morbidity and mortality in humans worldwide, especially in developing countries where access to chemotherapeutic agents is limited. Although parasites initially evoke a robust immune response, subsequent immunity fails to clear infection, ultimately leading to the chronic stage. This enigmatic situation was initially addressed in chronic viral models, where T cells lose their function, a phenomenon referred to as ’exhaustion‘. However, recent studies demonstrate that this paradigm can be extended to protozoan diseases as well, albeit with notable differences. These studies have revealed that T cell responses generated against Toxoplasma gondii, Plasmodium sp. and Leishmania sp. can become dysfunctional. This Review discusses T cell exhaustion in parasitic infection, mechanisms of development, and a possible role in disease outcome.

Gigley, Jason P.; Bhadra, Rajarshi; Moretto, Magali M.; Khan, Imtiaz A.

2012-01-01

35

Vertebrate Cells Express Protozoan Antigen after Hybridization  

NASA Astrophysics Data System (ADS)

Epimastigotes, the invertebrate host stage of Trypanosoma cruzi, the protozoan parasite causing Chagas' disease in man, were fused with vertebrate cells by using polyethylene glycol. Hybrid cells were selected on the basis of T. cruzi DNA complementation of biochemical deficiencies in the vertebrate cells. Some clones of the hybrid cells expressed T. cruzi-specific antigen. It might be possible to use selected antigens obtained from the hybrids as vaccines for immunodiagnosis or for elucidation of the pathogenesis of Chagas' disease.

Crane, Mark St. J.; Dvorak, James A.

1980-04-01

36

Self-Made Biological Materials of Protozoans  

Microsoft Academic Search

\\u000a The building of shells, tests, and loricae from bits of sand and other kind of mineral particles picked up from the environment\\u000a is a widely distributed survival strategy in marine environments. As examples of these self-made biological materials of protozoan\\u000a origin, numerous constructs from testate amoeba, gromiids, tintinnids, and xenophyophores are described and discussed here.

Hermann Ehrlich

37

Intestinal Protozoans in Adults with Diarrhea  

PubMed Central

Background: Diarrhea is one of the most common presenting complaints in human immunodeficiency virus-infected individuals. Aims: The study was designed to determine the magnitude of opportunistic and nonopportunistic intestinal parasitic infections among diarrheal patients and association between CD4+ T-cell counts and human immunodeficiency virus (HIV)-infected intestinal parasites. Materials and Methods: A cross-sectional study was conducted among 207 enrolled diarrheal patients attending HIV integrated counseling and testing center from January 2012 to December 2012. Stool samples were subjected to special modified Ziehl-Neelsen and chromotrope staining method for detection of opportunistic protozoans. Blood samples were also collected from all study subjects for HIV testing and CD4+ T-cell counts were estimated by only in HIV-infected patients. Results: Intestinal parasitic pathogens were detected in 46.1% HIV-infected patients and the major pathogens were opportunistic protozoans 32.2% (37/115), most common being Isospora belli 16.5% (19/115) followed by Cryptosporidium parvum 12.2% (14/115). In HIV noninfected diarrheal patients, major pathogens detected were Entamoeba histolytica/Entamoeba dispar 8.7% (8/92) and Ascaris lumbricoides 3.3% (3/92). Conclusions: The opportunistic intestinal protozoans especially I. belli and C. parvum were most commonly isolated in HIV-infected patients with diarrhea. Majority of the infections occurred in patients when a CD4+ T-cell counts were less than 200 cells/?l.

Dash, Muktikesh; Padhi, Sanghamitra; Panda, Pritilata; Parida, Banojini

2013-01-01

38

Lysine acetylation is widespread on proteins of diverse function and localization in the protozoan parasite Toxoplasma gondii.  

PubMed

While histone proteins are the founding members of lysine acetylation substrates, it is now clear that hundreds of other proteins can be acetylated in multiple compartments of the cell. Our knowledge of the scope of this modification throughout the kingdom of life is beginning to emerge, as proteome-wide lysine acetylation has been documented in prokaryotes, Arabidopsis thaliana, Drosophila melanogaster, and human cells. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify parasite peptides enriched by immunopurification with acetyl-lysine antibody, we produced the first proteome-wide analysis of acetylation for a protozoan organism, the opportunistic apicomplexan parasite Toxoplasma gondii. The results show that lysine acetylation is abundant in the actively proliferating tachyzoite form of the parasite, which causes acute toxoplasmosis. Our approach successfully identified known acetylation marks on Toxoplasma histones and ?-tubulin and detected over 400 novel acetylation sites on a wide variety of additional proteins, including those with roles in transcription, translation, metabolism, and stress responses. Importantly, an extensive set of parasite-specific proteins, including those found in organelles unique to Apicomplexa, is acetylated in the parasite. Our data provide a wealth of new information that improves our understanding of the evolution of this vital regulatory modification while potentially revealing novel therapeutic avenues. We conclude from this study that lysine acetylation was prevalent in the early stages of eukaryotic cell evolution and occurs on proteins involved in a remarkably diverse array of cellular functions, including those that are specific to parasites. PMID:22544907

Jeffers, Victoria; Sullivan, William J

2012-06-01

39

Lysine Acetylation Is Widespread on Proteins of Diverse Function and Localization in the Protozoan Parasite Toxoplasma gondii  

PubMed Central

While histone proteins are the founding members of lysine acetylation substrates, it is now clear that hundreds of other proteins can be acetylated in multiple compartments of the cell. Our knowledge of the scope of this modification throughout the kingdom of life is beginning to emerge, as proteome-wide lysine acetylation has been documented in prokaryotes, Arabidopsis thaliana, Drosophila melanogaster, and human cells. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify parasite peptides enriched by immunopurification with acetyl-lysine antibody, we produced the first proteome-wide analysis of acetylation for a protozoan organism, the opportunistic apicomplexan parasite Toxoplasma gondii. The results show that lysine acetylation is abundant in the actively proliferating tachyzoite form of the parasite, which causes acute toxoplasmosis. Our approach successfully identified known acetylation marks on Toxoplasma histones and ?-tubulin and detected over 400 novel acetylation sites on a wide variety of additional proteins, including those with roles in transcription, translation, metabolism, and stress responses. Importantly, an extensive set of parasite-specific proteins, including those found in organelles unique to Apicomplexa, is acetylated in the parasite. Our data provide a wealth of new information that improves our understanding of the evolution of this vital regulatory modification while potentially revealing novel therapeutic avenues. We conclude from this study that lysine acetylation was prevalent in the early stages of eukaryotic cell evolution and occurs on proteins involved in a remarkably diverse array of cellular functions, including those that are specific to parasites.

Jeffers, Victoria

2012-01-01

40

Neuroparasitic Infections: Cestodes, Trematodes, and Protozoans  

PubMed Central

Parasitic infection of the nervous system can produce a variety of symptoms and signs. Because symptoms of infection are often mild or nonspecific, diagnosis can be difficult. Familiarity with basic epidemiological characteristics and distinguishing radiographic findings can increase the likelihood of detection and proper treatment of parasitic infection of the nervous system. This article discusses the clinical presentation, diagnosis, and treatment for some of the more common infections of the nervous system caused by cestodes, trematodes and protozoans: Echinococcus spp., Spirometra spp. (sparganosis), Paragonimus spp., Schistosoma spp., Trypanosoma spp., Naegleria fowlerii, Acanthamoeba histolytica, and Balamuthia mandrillaris.

Walker, M.D.; Zunt, J.R.

2009-01-01

41

Ycf93 (Orf105), a Small Apicoplast-Encoded Membrane Protein in the Relict Plastid of the Malaria Parasite Plasmodium falciparum That Is Conserved in Apicomplexa  

PubMed Central

Malaria parasites retain a relict plastid (apicoplast) from a photosynthetic ancestor shared with dinoflagellate algae. The apicoplast is a useful drug target; blocking housekeeping pathways such as genome replication and translation in the organelle kills parasites and protects against malaria. The apicoplast of Plasmodium falciparum encodes 30 proteins and a suite of rRNAs and tRNAs that facilitate their expression. orf105 is a hypothetical apicoplast gene that would encode a small protein (PfOrf105) with a predicted C-terminal transmembrane domain. We produced antisera to a predicted peptide within PfOrf105. Western blot analysis confirmed expression of orf105 and immunofluorescence localised the gene product to the apicoplast. Pforf105 encodes a membrane protein that has an apparent mass of 17.5 kDa and undergoes substantial turnover during the 48-hour asexual life cycle of the parasite in blood stages. The effect of actinonin, an antimalarial with a putative impact on post-translational modification of apicoplast proteins like PfOrf105, was examined. Unlike other drugs perturbing apicoplast housekeeping that induce delayed death, actinonin kills parasites immediately and has an identical drug exposure phenotype to the isopentenyl diphosphate synthesis blocker fosmidomycin. Open reading frames of similar size to PfOrf105, which also have predicted C-terminal trans membrane domains, occur in syntenic positions in all sequenced apicoplast genomes from Phylum Apicomplexa. We therefore propose to name these genes ycf93 (hypothetical chloroplast reading frame 93) according to plastid gene nomenclature convention for conserved proteins of unknown function.

Goodman, Christopher D.; McFadden, Geoffrey I.

2014-01-01

42

Ycf93 (Orf105), a small apicoplast-encoded membrane protein in the relict plastid of the malaria parasite Plasmodium falciparum that is conserved in Apicomplexa.  

PubMed

Malaria parasites retain a relict plastid (apicoplast) from a photosynthetic ancestor shared with dinoflagellate algae. The apicoplast is a useful drug target; blocking housekeeping pathways such as genome replication and translation in the organelle kills parasites and protects against malaria. The apicoplast of Plasmodium falciparum encodes 30 proteins and a suite of rRNAs and tRNAs that facilitate their expression. orf105 is a hypothetical apicoplast gene that would encode a small protein (PfOrf105) with a predicted C-terminal transmembrane domain. We produced antisera to a predicted peptide within PfOrf105. Western blot analysis confirmed expression of orf105 and immunofluorescence localised the gene product to the apicoplast. Pforf105 encodes a membrane protein that has an apparent mass of 17.5 kDa and undergoes substantial turnover during the 48-hour asexual life cycle of the parasite in blood stages. The effect of actinonin, an antimalarial with a putative impact on post-translational modification of apicoplast proteins like PfOrf105, was examined. Unlike other drugs perturbing apicoplast housekeeping that induce delayed death, actinonin kills parasites immediately and has an identical drug exposure phenotype to the isopentenyl diphosphate synthesis blocker fosmidomycin. Open reading frames of similar size to PfOrf105, which also have predicted C-terminal trans membrane domains, occur in syntenic positions in all sequenced apicoplast genomes from Phylum Apicomplexa. We therefore propose to name these genes ycf93 (hypothetical chloroplast reading frame 93) according to plastid gene nomenclature convention for conserved proteins of unknown function. PMID:24705170

Goodman, Christopher D; McFadden, Geoffrey I

2014-01-01

43

Three Genomes from the Phylum Acidobacteria Provide Insight into the Lifestyles of These Microorganisms in Soils  

Microsoft Academic Search

The complete genomes of three strains from the phylum Acidobacteria were compared. Phylogenetic analysis placed them as a unique phylum. They share genomic traits with members of the Proteobacteria, the Cyanobac- teria, and the Fungi. The three strains appear to be versatile heterotrophs. Genomic and culture traits indicate the use of carbon sources that span simple sugars to more complex

Naomi L. Ward; Jean F. Challacombe; Peter H. Janssen; Bernard Henrissat; Pedro M. Coutinho; Martin Wu; Gary Xie; Daniel H. Haft; Michelle Sait; Jonathan Badger; Ravi D. Barabote; Brent Bradley; Thomas S. Brettin; Lauren M. Brinkac; David Bruce; Todd Creasy; Sean C. Daugherty; Tanja M. Davidsen; Robert T. DeBoy; J. Chris Detter; Robert J. Dodson; A. Scott Durkin; Anuradha Ganapathy; Michelle Gwinn-Giglio; Cliff S. Han; Hoda Khouri; Hajnalka Kiss; Sagar P. Kothari; Ramana Madupu; Karen E. Nelson; William C. Nelson; Ian Paulsen; Kevin Penn; Qinghu Ren; M. J. Rosovitz; Jeremy D. Selengut; Susmita Shrivastava; Steven A. Sullivan; Roxanne Tapia; L. Sue Thompson; Kisha L. Watkins; Qi Yang; Chunhui Yu; Nikhat Zafar; Liwei Zhou; Cheryl R. Kuske

2009-01-01

44

Drug repurposing and human parasitic protozoan diseases.  

PubMed

Parasitic diseases have an enormous health, social and economic impact and are a particular problem in tropical regions of the world. Diseases caused by protozoa and helminths, such as malaria and schistosomiasis, are the cause of most parasite related morbidity and mortality, with an estimated 1.1 million combined deaths annually. The global burden of these diseases is exacerbated by the lack of licensed vaccines, making safe and effective drugs vital to their prevention and treatment. Unfortunately, where drugs are available, their usefulness is being increasingly threatened by parasite drug resistance. The need for new drugs drives antiparasitic drug discovery research globally and requires a range of innovative strategies to ensure a sustainable pipeline of lead compounds. In this review we discuss one of these approaches, drug repurposing or repositioning, with a focus on major human parasitic protozoan diseases such as malaria, trypanosomiasis, toxoplasmosis, cryptosporidiosis and leishmaniasis. PMID:25057459

Andrews, Katherine T; Fisher, Gillian; Skinner-Adams, Tina S

2014-08-01

45

Drug repurposing and human parasitic protozoan diseases  

PubMed Central

Parasitic diseases have an enormous health, social and economic impact and are a particular problem in tropical regions of the world. Diseases caused by protozoa and helminths, such as malaria and schistosomiasis, are the cause of most parasite related morbidity and mortality, with an estimated 1.1 million combined deaths annually. The global burden of these diseases is exacerbated by the lack of licensed vaccines, making safe and effective drugs vital to their prevention and treatment. Unfortunately, where drugs are available, their usefulness is being increasingly threatened by parasite drug resistance. The need for new drugs drives antiparasitic drug discovery research globally and requires a range of innovative strategies to ensure a sustainable pipeline of lead compounds. In this review we discuss one of these approaches, drug repurposing or repositioning, with a focus on major human parasitic protozoan diseases such as malaria, trypanosomiasis, toxoplasmosis, cryptosporidiosis and leishmaniasis.

Andrews, Katherine T.; Fisher, Gillian; Skinner-Adams, Tina S.

2014-01-01

46

Kinetoplastids: related protozoan pathogens, different diseases  

PubMed Central

Kinetoplastids are a group of flagellated protozoans that include the species Trypanosoma and Leishmania, which are human pathogens with devastating health and economic effects. The sequencing of the genomes of some of these species has highlighted their genetic relatedness and underlined differences in the diseases that they cause. As we discuss in this Review, steady progress using a combination of molecular, genetic, immunologic, and clinical approaches has substantially increased understanding of these pathogens and important aspects of the diseases that they cause. Consequently, the paths for developing additional measures to control these “neglected diseases” are becoming increasingly clear, and we believe that the opportunities for developing the drugs, diagnostics, vaccines, and other tools necessary to expand the armamentarium to combat these diseases have never been better.

Stuart, Ken; Brun, Reto; Croft, Simon; Fairlamb, Alan; Gurtler, Ricardo E.; McKerrow, Jim; Reed, Steve; Tarleton, Rick

2008-01-01

47

Candidate phylum TM6 genome recovered from a hospital sink biofilm provides genomic insights into this uncultivated phylum  

PubMed Central

The “dark matter of life” describes microbes and even entire divisions of bacterial phyla that have evaded cultivation and have yet to be sequenced. We present a genome from the globally distributed but elusive candidate phylum TM6 and uncover its metabolic potential. TM6 was detected in a biofilm from a sink drain within a hospital restroom by analyzing cells using a highly automated single-cell genomics platform. We developed an approach for increasing throughput and effectively improving the likelihood of sampling rare events based on forming small random pools of single-flow–sorted cells, amplifying their DNA by multiple displacement amplification and sequencing all cells in the pool, creating a “mini-metagenome.” A recently developed single-cell assembler, SPAdes, in combination with contig binning methods, allowed the reconstruction of genomes from these mini-metagenomes. A total of 1.07 Mb was recovered in seven contigs for this member of TM6 (JCVI TM6SC1), estimated to represent 90% of its genome. High nucleotide identity between a total of three TM6 genome drafts generated from pools that were independently captured, amplified, and assembled provided strong confirmation of a correct genomic sequence. TM6 is likely a Gram-negative organism and possibly a symbiont of an unknown host (nonfree living) in part based on its small genome, low-GC content, and lack of biosynthesis pathways for most amino acids and vitamins. Phylogenomic analysis of conserved single-copy genes confirms that TM6SC1 is a deeply branching phylum.

McLean, Jeffrey S.; Lombardo, Mary-Jane; Badger, Jonathan H.; Edlund, Anna; Novotny, Mark; Yee-Greenbaum, Joyclyn; Vyahhi, Nikolay; Hall, Adam P.; Yang, Youngik; Dupont, Christopher L.; Ziegler, Michael G.; Chitsaz, Hamidreza; Allen, Andrew E.; Yooseph, Shibu; Tesler, Glenn; Pevzner, Pavel A.; Friedman, Robert M.; Nealson, Kenneth H.; Venter, J. Craig; Lasken, Roger S.

2013-01-01

48

Candidate phylum TM6 genome recovered from a hospital sink biofilm provides genomic insights into this uncultivated phylum.  

PubMed

The "dark matter of life" describes microbes and even entire divisions of bacterial phyla that have evaded cultivation and have yet to be sequenced. We present a genome from the globally distributed but elusive candidate phylum TM6 and uncover its metabolic potential. TM6 was detected in a biofilm from a sink drain within a hospital restroom by analyzing cells using a highly automated single-cell genomics platform. We developed an approach for increasing throughput and effectively improving the likelihood of sampling rare events based on forming small random pools of single-flow-sorted cells, amplifying their DNA by multiple displacement amplification and sequencing all cells in the pool, creating a "mini-metagenome." A recently developed single-cell assembler, SPAdes, in combination with contig binning methods, allowed the reconstruction of genomes from these mini-metagenomes. A total of 1.07 Mb was recovered in seven contigs for this member of TM6 (JCVI TM6SC1), estimated to represent 90% of its genome. High nucleotide identity between a total of three TM6 genome drafts generated from pools that were independently captured, amplified, and assembled provided strong confirmation of a correct genomic sequence. TM6 is likely a Gram-negative organism and possibly a symbiont of an unknown host (nonfree living) in part based on its small genome, low-GC content, and lack of biosynthesis pathways for most amino acids and vitamins. Phylogenomic analysis of conserved single-copy genes confirms that TM6SC1 is a deeply branching phylum. PMID:23754396

McLean, Jeffrey S; Lombardo, Mary-Jane; Badger, Jonathan H; Edlund, Anna; Novotny, Mark; Yee-Greenbaum, Joyclyn; Vyahhi, Nikolay; Hall, Adam P; Yang, Youngik; Dupont, Christopher L; Ziegler, Michael G; Chitsaz, Hamidreza; Allen, Andrew E; Yooseph, Shibu; Tesler, Glenn; Pevzner, Pavel A; Friedman, Robert M; Nealson, Kenneth H; Venter, J Craig; Lasken, Roger S

2013-06-25

49

Eimeria fragilis and E. wambaensis, Two New Species of Eimeria Schneider (Apicomplexa: Eimeriidae) from African Anurans  

Microsoft Academic Search

Summary. Two new species of coccidia (Apicomplexa: Eimeriidae) are described from Kenyan frogs. Eimeria fragilis sp. n., described from Chiromantis petersii, has ellipsoidal oocysts, 18.5 (17-19.5) × 15.2 (14.5-16) µm; lacking micropyle, oocyst residuum and polar granule. Sporocysts are dizoic, navicular, 10.6 (9.5-12) × 6.8 (6-7) µm. Oocysts of Eimeria wambaensis sp. n. found in Hyperolius viridiflavus are ellipsoidal to

Miloslav JIRK; David MODRÝ

50

Metagenomic analysis reveals unexpected subgenomic diversity of magnetotactic bacteria within the phylum Nitrospirae.  

PubMed

A targeted metagenomic approach was applied to investigate magnetotactic bacteria (MTB) within the phylum Nitrospirae in Lake Miyun near Beijing, China. Five fosmids containing rRNA operons were identified. Comparative sequence analysis of a total of 172 kb provided new insights into their genome organization and revealed unexpected subgenomic diversity of uncultivated MTB in the phylum Nitrospirae. In addition, affiliation of two novel MTB with the phylum Nitrospirae was verified by fluorescence in situ hybridization. One of them was morphologically similar to "Candidatus Magnetobacterium bavaricum," but the other differed substantially in cell shape and magnetosome organization from all previously described "Ca. Magnetobacterium bavaricum"-like bacteria. PMID:21057016

Lin, Wei; Jogler, Christian; Schüler, Dirk; Pan, Yongxin

2011-01-01

51

Metagenomic Analysis Reveals Unexpected Subgenomic Diversity of Magnetotactic Bacteria within the Phylum Nitrospirae ? †  

PubMed Central

A targeted metagenomic approach was applied to investigate magnetotactic bacteria (MTB) within the phylum Nitrospirae in Lake Miyun near Beijing, China. Five fosmids containing rRNA operons were identified. Comparative sequence analysis of a total of 172 kb provided new insights into their genome organization and revealed unexpected subgenomic diversity of uncultivated MTB in the phylum Nitrospirae. In addition, affiliation of two novel MTB with the phylum Nitrospirae was verified by fluorescence in situ hybridization. One of them was morphologically similar to “Candidatus Magnetobacterium bavaricum,” but the other differed substantially in cell shape and magnetosome organization from all previously described “Ca. Magnetobacterium bavaricum”-like bacteria.

Lin, Wei; Jogler, Christian; Schuler, Dirk; Pan, Yongxin

2011-01-01

52

Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida.  

PubMed

Deuterostomes comprise vertebrates, the related invertebrate chordates (tunicates and cephalochordates) and three other invertebrate taxa: hemichordates, echinoderms and Xenoturbella. The relationships between invertebrate and vertebrate deuterostomes are clearly important for understanding our own distant origins. Recent phylogenetic studies of chordate classes and a sea urchin have indicated that urochordates might be the closest invertebrate sister group of vertebrates, rather than cephalochordates, as traditionally believed. More remarkable is the suggestion that cephalochordates are closer to echinoderms than to vertebrates and urochordates, meaning that chordates are paraphyletic. To study the relationships among all deuterostome groups, we have assembled an alignment of more than 35,000 homologous amino acids, including new data from a hemichordate, starfish and Xenoturbella. We have also sequenced the mitochondrial genome of Xenoturbella. We support the clades Olfactores (urochordates and vertebrates) and Ambulacraria (hemichordates and echinoderms). Analyses using our new data, however, do not support a cephalochordate and echinoderm grouping and we conclude that chordates are monophyletic. Finally, nuclear and mitochondrial data place Xenoturbella as the sister group of the two ambulacrarian phyla. As such, Xenoturbella is shown to be an independent phylum, Xenoturbellida, bringing the number of living deuterostome phyla to four. PMID:17051155

Bourlat, Sarah J; Juliusdottir, Thorhildur; Lowe, Christopher J; Freeman, Robert; Aronowicz, Jochanan; Kirschner, Mark; Lander, Eric S; Thorndyke, Michael; Nakano, Hiroaki; Kohn, Andrea B; Heyland, Andreas; Moroz, Leonid L; Copley, Richard R; Telford, Maximilian J

2006-11-01

53

Discovery of multiple neuropeptide families in the phylum Platyhelminthes  

PubMed Central

Available evidence shows that short amidated neuropeptides are widespread and have important functions within the nervous systems of all flatworms (phylum Platyhelminthes) examined, and could therefore represent a starting point for new lead drug compounds with which to combat parasitic helminth infections. However, only a handful of these peptides have been characterised, the rigorous exploration of the flatworm peptide signalling repertoire having been hindered by the dearth of flatworm genomic data. Through searches of both expressed sequence tags and genomic resources using the basic local alignment search tool (BLAST), we describe 96 neuropeptides on 60 precursors from 10 flatworm species. Most of these (51 predicted peptides on 14 precursors) are novel and are apparently restricted to flatworms; the remainder comprise nine recognised peptide families including FMRFamide-like (FLPs), neuropeptide F (NPF)-like, myomodulin-like, buccalin-like and neuropeptide FF (NPFF)-like peptides; notably, the latter have only previously been reported in vertebrates. Selected peptides were localised immunocytochemically to the Schistosoma mansoni nervous system. We also describe several novel flatworm NPFs with structural features characteristic of the vertebrate neuropeptide Y (NPY) superfamily, previously unreported characteristics which support the common ancestry of flatworm NPFs with the NPY-superfamily. Our dataset provides a springboard for investigation of the functional biology and therapeutic potential of neuropeptides in flatworms, simultaneously launching flatworm neurobiology into the post-genomic era.

McVeigh, Paul; Mair, Gunnar R.; Atkinson, Louise; Ladurner, Peter; Zamanian, Mostafa; Novozhilova, Ekaterina; Marks, Nikki J.; Day, Tim A.; Maule, Aaron G.

2009-01-01

54

Protozoan infections of the gastrointestinal tract.  

PubMed

The review provides current views on human protozoan parasites of the gut. The recognition of the importance of cryptosporidium, cyclospora and microsporidia over the last three decades emphasises the possibility that more pathogenic intestinal protozoa are presently unrecognized. Each of these is a zoonotic infection and the potential for a zoonotic element to the transmission of giardiasis has been recognized. A common theme in increased understanding of the biology and pathological mechanisms involved in causing disease is the application of molecular techniques to the various stages of the parasite life cycle. Molecular methods are increasingly contributing to laboratory diagnosis of these conditions with increased yields of positive results though in the tropics it is likely that fecal microscopy will remain the standard for some time to come. The nitroimidazole compounds are the mainstay of treatment for giardia and amebiasis with no major advance in therapeutics since their role was appreciated. Nitazoxanide was shown to be effective for cryptosporidiosis in the 1990s. PMID:22632642

Wright, Stephen G

2012-06-01

55

Invasion and Intracellular Survival by Protozoan Parasites  

PubMed Central

Summary Intracellular parasitism has arisen only a few times during the long ancestry of protozoan parasites including in diverse groups such as microsporidians, kinetoplastids, and apicomplexans. Strategies used to gain entry differ widely from injection (e.g. microsporidians), active penetration of the host cell (e.g. Toxoplasma), recruitment of lysosomes to a plasma membrane wound (e.g. Trypanosoma cruzi), to host cell-mediated phagocytosis (e.g. Leishmania). The resulting range of intracellular niches is equally diverse ranging from cytosolic (e.g. T. cruzi) to residing within a nonfusigenic vacuole (e.g. Toxoplasma, Encephalitizoon) or a modified phagolysosome (e.g. Leishmania). These lifestyle choices influence access to nutrients, interaction with host cell signaling pathways, and detection by pathogen recognition systems. As such, intracellular life requires a repertoire of adaptations to assure entry-exit from the cell, as well as to thwart innate immune mechanisms and prevent clearance. Elucidating these pathways at the cellular and molecular level may identify key steps that can be targeted to reduce parasite survival or augment immunological responses and thereby prevent disease.

Sibley, L. David

2013-01-01

56

Role of Leukotrienes on Protozoan and Helminth Infections  

PubMed Central

Leukotrienes (LTs), formed by the 5-lipoxygenase-(5-LO-) catalyzed oxidation of arachidonic acid, are lipid mediators that have potent proinflammatory activities. Pharmacologic or genetic inhibition of 5-LO biosynthesis in animals is associated with increased mortality and impaired clearance of bacteria, fungi, and parasites. LTs play a role in the control of helminth and protozoan infections by modulating the immune system and/or through direct cytotoxicity to parasites; however, LTs may also be associated with pathogenesis, such as in cerebral malaria and schistosomal granuloma. Interestingly, some proteins from the saliva of insect vectors that transmit protozoans and secreted protein from helminth could bind LTs and may consequently modulate the course of infection or pathogenesis. In addition, the decreased production of LTs in immunocompromised individuals might modulate the pathophysiology of helminth and protozoan infections. Herein, in this paper, we showed the immunomodulatory and pathogenic roles of LTs during the helminth and protozoan infections.

Rogerio, Alexandre P.; Anibal, Fernanda F.

2012-01-01

57

Molecular and phylogenetic characterizations of an Eimeria krijgsmanni Yakimoff & Gouseff, 1938 (Apicomplexa: Eimeriidae) mouse intestinal protozoan parasite by partial 18S ribosomal RNA gene sequence analysis.  

PubMed

Previously, we characterized an undocumented strain of Eimeria krijgsmanni by morphological and biological features. Here, we present a detailed molecular phylogenetic analysis of this organism. Namely, 18S ribosomal RNA gene (rDNA) sequences of E. krijgsmanni were analyzed to incorporate this species into a comprehensive Eimeria phylogeny. As a result, partial 18S rDNA sequence from E. krijgsmanni was successfully determined, and two different types, Type A and Type B, that differed by 1 base pair were identified. E. krijgsmanni was originally isolated from a single oocyst, and thus the result show that the two types might have allelic sequence heterogeneity in the 18S rDNA. Based on phylogenetic analyses, the two types of E. krijgsmanni 18S rDNA formed one of two clades among murine Eimeria spp.; these Eimeria clades reflected morphological similarity among the Eimeria spp. This is the third molecular phylogenetic characterization of a murine Eimeria spp. in addition to E. falciformis and E. papillata. PMID:24780139

Takeo, Toshinori; Tanaka, Tetsuya; Matsubayashi, Makoto; Maeda, Hiroki; Kusakisako, Kodai; Matsui, Toshihiro; Mochizuki, Masami; Matsuo, Tomohide

2014-08-01

58

Isospora peromysci Davis, 1967 (Apicomplexa: Eimeriidae) in Peromyscus leucopus and P. maniculatus (Rodentia: Cricetidae) from Texas.  

PubMed

Oocysts of Isospora peromysci (Davis, 1967) (Apicomplexa: Eimeriidae) were recovered from the feces of 1/30 (3.3%) white-footed mice, Peromyscus leucopus, in Johnson County, Texas. This report represents a new host and geographic record for the parasite. The coccidium was also found in 1/20 (5.0%) deer mice, P. maniculatus, from the same locale. Morphological data are provided on the sporulated oocyst of I. peromysci and comparisons are made with previously published information on the species from other geographic localities. PMID:2724183

McAllister, C T; Upton, S J

1989-01-01

59

Molecular Phylogenetic Relatedness of Frenkelia spp. (Protozoa, Apicomplexa) to Sarcocystis falcatula Stiles 1893: Is the Genus Sarcocystis Paraphyletic?  

Microsoft Academic Search

The coccidians Frenkelia microti and F. glareoli (Apicomplexa: Sarcocystidae) form tissue cysts in the brain of small rodents (intermediate hosts) while oocysts are formed in the intestine of final hosts, buzzards of the genus Buteo. The inclusion of the small subunit ribosomal RNA gene sequences (SSU rRNA) of both Frenkelia species into the SSU rRNA trees of other, tissue cyst-

Jan Votypka; Vaclav Hypša; Milan Jirku; Jaroslav Flegr; Jiri Vavra; Julius Lukes

1998-01-01

60

Class-level relationships in the phylum Cnidaria: evidence from mitochondrial genome structure.  

PubMed Central

The phylogenetic relationships of the Recent cnidarian classes remain one of the classic problems in invertebrate zoology. We survey the structure of the mitochondrial genome in representatives of the four extant cnidarian classes and in the phylum Ctenophora. We find that all anthozoan species tested possess mtDNA in the form of circular molecules, whereas all scyphozoan, cubozoan, and hydrozoan species tested display mtDNA in the form of linear molecules. Because ctenophore and all other known metazoan mtDNA is circular, the shared occurrence of linear mtDNA in three of the four cnidarian classes suggests a basal position for the Anthozoa within the phylum. Images

Bridge, D; Cunningham, C W; Schierwater, B; DeSalle, R; Buss, L W

1992-01-01

61

Interaction between Ethanol and Opioids in a Protozoan Assay  

Microsoft Academic Search

Ethanol excess combined with opioids can be fatal due to their toxic interaction, yet the nature of the interaction is little documented. Since ethanol and some opioids have membrane stabilizing activity, the present study used a protozoan motility model to test the possibility that ethanol may interact with some opioids on this basis. The EC50 in motility reduction for ethanol,

Changhao Wu; J. A. Henry

1994-01-01

62

Recent Advances in Human Protozoan Parasites of Gastrointestinal Tract.  

National Technical Information Service (NTIS)

An attempt was made in this report to present an update on the recent development on intestinal protozoan infections in humans. Except for a few historical references, the review covers the period from 1980 to the time of writing, mid-1985. The emphasis w...

J. H. Cross

1987-01-01

63

Drug resistance in the sexually transmitted protozoan Trichomonas vaginalis  

Microsoft Academic Search

Trichomoniasis is the most common, sexually transmitted infection. It is caused by the flagellated protozoan parasite Trichomonas vaginalis. Symptoms include vaginitis and infections have been associated with preterm delivery, low birth weight and increased infant mortality, as well as predisposing to HIV\\/AIDS and cervical cancer. Trichomoniasis has the highest prevalence and incidence of any sexually transmitted infection. The 5-nitroimidazole drugs,

Rebecca L DUNNE; Linda A DUNN; Peter UPCROFT; Peter J O'DONOGHUE; Jacqueline A UPCROFT

2003-01-01

64

B-Cell Response during Protozoan Parasite Infections  

PubMed Central

In this review, we discuss how protozoan parasites alter immature and mature B cell compartment. B1 and marginal zone (MZ) B cells, considered innate like B cells, are activated during protozoan parasite infections, and they generate short lived plasma cells providing a prompt antibody source. In addition, protozoan infections induce massive B cell response with polyclonal activation that leads to hypergammaglobulnemia with serum antibodies specific for the parasites and self and/or non related antigens. To protect themselves, the parasites have evolved unique ways to evade B cell immune responses inducing apoptosis of MZ and conventional mature B cells. As a consequence of the parasite induced-apoptosis, the early IgM response and an already establish humoral immunity are affected during the protozoan parasite infection. Moreover, some trypanosomatides trigger bone marrow immature B cell apoptosis, influencing the generation of new mature B cells. Simultaneously with their ability to release antibodies, B cells produce cytokines/quemokines that influence the characteristic of cellular immune response and consequently the progression of parasite infections.

Amezcua Vesely, Maria C.; Bermejo, Daniela A.; Montes, Carolina L.; Acosta-Rodriguez, Eva V.; Gruppi, Adriana

2012-01-01

65

The importance of zooplankton-protozoan trophic couplings in Lake Michigan  

Microsoft Academic Search

Abstract The importance,of the zooplankton-protozoan,trophic coupling was determined,experimentally by measured,changes in protozoan,growth rates with increasing zooplankton,biomass. In five of six experiments conducted in Lake Michigan, a significant inverse relationship between protozoan growth and zooplankton biomass was observed (avg r2 = 70%), Zooplankton clearance rates on protozoan assemblages (range, 1.0-6.2 ml (pg dry wt)-I d ‘1 were comparable to those previously

HUNTER J. CARRICK; GARY L. FAHNENSTIEL; EUGENE F. STOERMER; ROBERT G. WETZEL

1991-01-01

66

Phylogenetic delineation of the novel phylum Armatimonadetes (former candidate division OP10) and definition of two novel candidate divisions.  

PubMed

Small-subunit (SSU) rRNA gene sequences associated with the phylum Armatimonadetes were analyzed using multiple phylogenetic methods, clarifying both the phylum boundary and the affiliation of previously ambiguous groupings. Here we define the Armatimonadetes as 10 class-level groups and reclassify two previously associated groups as candidate divisions WS1 and FBP. PMID:23377935

Lee, K C Y; Herbold, C W; Dunfield, P F; Morgan, X C; McDonald, I R; Stott, M B

2013-04-01

67

Newly isolated but uncultivated magnetotactic bacterium of the phylum Nitrospirae from Beijing, China.  

PubMed

Magnetotactic bacteria (MTB) in the phylum Nitrospirae synthesize up to hundreds of intracellular bullet-shaped magnetite magnetosomes. In the present study, a watermelon-shaped magnetotactic bacterium (designated MWB-1) from Lake Beihai in Beijing, China, was characterized. This uncultivated microbe was identified as a member of the phylum Nitrospirae and represents a novel phylogenetic lineage with ?6% 16S rRNA gene sequence divergence from all currently described MTB. MWB-1 contained 200 to 300 intracellular bullet-shaped magnetite magnetosomes and showed a helical swimming trajectory under homogeneous magnetic fields; its magnetotactic velocity decreased with increasing field strength, and vice versa. A robust phylogenetic framework for MWB-1 and all currently known MTB in the phylum Nitrospirae was constructed utilizing maximum-likelihood and Bayesian algorithms, which yielded strong evidence that the Nitrospirae MTB could be divided into four well-supported groups. Considering its population densities in sediment and its high numbers of magnetosomes, MWB-1 was estimated to account for more than 10% of the natural remanent magnetization of the surface sediment. Taken together, the results of this study suggest that MTB in the phylum Nitrospirae are more diverse than previously realized and can make important contributions to the sedimentary magnetization in particular environments. PMID:22113917

Lin, Wei; Li, Jinhua; Pan, Yongxin

2012-02-01

68

Complete Genome of Ignavibacterium album, a Metabolically Versatile, Flagellated, Facultative Anaerobe from the Phylum Chlorobi  

PubMed Central

Prior to the recent discovery of Ignavibacterium album (I. album), anaerobic photoautotrophic green sulfur bacteria (GSB) were the only members of the bacterial phylum Chlorobi that had been grown axenically. In contrast to GSB, sequence analysis of the 3.7-Mbp genome of I. album shows that this recently described member of the phylum Chlorobi is a chemoheterotroph with a versatile metabolism. I. album lacks genes for photosynthesis and sulfur oxidation but has a full set of genes for flagella and chemotaxis. The occurrence of genes for multiple electron transfer complexes suggests that I. album is capable of organoheterotrophy under both oxic and anoxic conditions. The occurrence of genes encoding enzymes for CO2 fixation as well as other enzymes of the reductive TCA cycle suggests that mixotrophy may be possible under certain growth conditions. However, known biosynthetic pathways for several amino acids are incomplete; this suggests that I. album is dependent upon on exogenous sources of these metabolites or employs novel biosynthetic pathways. Comparisons of I. album and other members of the phylum Chlorobi suggest that the physiology of the ancestors of this phylum might have been quite different from that of modern GSB.

Liu, Zhenfeng; Frigaard, Niels-Ulrik; Vogl, Kajetan; Iino, Takao; Ohkuma, Moriya; Overmann, Jorg; Bryant, Donald A.

2012-01-01

69

Draft Genome Sequence of the Endosymbiont "Candidatus Ruthia magnifica" UCD-CM (Phylum Proteobacteria)  

PubMed Central

Here, we present the draft genome of the endosymbiont “Candidatus Ruthia magnifica” UCD-CM, a member of the phylum Proteobacteria, found from the gills of a deep-sea giant clam, Calyptogena magnifica. The assembly consists of 1,160,249 bp contained in 18 contigs.

Lee, Ruth D.; Jospin, Guillaume; Coil, David A.

2014-01-01

70

Identifying Novel Cell Cycle Proteins in Apicomplexa Parasites through Co-Expression Decision Analysis  

PubMed Central

Hypothetical proteins comprise roughly half of the predicted gene complement of Toxoplasma gondii and Plasmodium falciparum and represent the largest class of uniquely functioning proteins in these parasites. Following the idea that functional relationships can be informed by the timing of gene expression, we devised a strategy to identify the core set of apicomplexan cell division cycling genes with important roles in parasite division, which includes many uncharacterized proteins. We assembled an expanded list of orthologs from the T. gondii and P. falciparum genome sequences (2781 putative orthologs), compared their mRNA profiles during synchronous replication, and sorted the resulting set of dual cell cycle regulated orthologs (744 total) into protein pairs conserved across many eukaryotic families versus those unique to the Apicomplexa. The analysis identified more than 100 ortholog gene pairs with unknown function in T. gondii and P. falciparum that displayed co-conserved mRNA abundance, dynamics of cyclical expression and similar peak timing that spanned the complete division cycle in each parasite. The unknown cyclical mRNAs encoded a diverse set of proteins with a wide range of mass and showed a remarkable conservation in the internal organization of ordered versus disordered structural domains. A representative sample of cyclical unknown genes (16 total) was epitope tagged in T. gondii tachyzoites yielding the discovery of new protein constituents of the parasite inner membrane complex, key mitotic structures and invasion organelles. These results demonstrate the utility of using gene expression timing and dynamic profile to identify proteins with unique roles in Apicomplexa biology.

Butler, Carrie L.; Lucas, Olivier; Wuchty, Stefan; Xue, Bin; Uversky, Vladimir N.; White, Michael

2014-01-01

71

Armatimonas rosea gen. nov., sp. nov., of a novel bacterial phylum, Armatimonadetes phyl. nov., formally called the candidate phylum OP10.  

PubMed

A novel aerobic, chemoheterotrophic bacterium, strain YO-36(T), isolated from the rhizoplane of an aquatic plant (a reed, Phragmites australis) inhabiting a freshwater lake in Japan, was morphologically, physiologically and phylogenetically characterized. Strain YO-36(T) was Gram-negative and ovoid to rod-shaped, and formed pinkish hard colonies on agar plates. Strain YO-36(T) grew at 20-40 °C with optimum growth at 30-35 °C, whilst no growth was observed at 15 °C or 45 °C. The pH range for growth was 5.5-8.5 with an optimum at pH 6.5. Strain YO-36(T) utilized a limited range of substrates, such as sucrose, gentiobiose, pectin, gellan gum and xanthan gum. The strain contained C(16 : 0), C(16 : 1), C(14 : 0) and C(15 : 0) as the major cellular fatty acids and menaquinone-12 as the respiratory quinone. The G+C content of the genomic DNA was 62.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YO-36(T) belonged to the candidate phylum OP10 comprised solely of environmental 16S rRNA gene clone sequences except for two strains, P488 and T49 isolated from geothermal soil in New Zealand; strain YO-36(T) showed less than 80 % sequence similarity to strains P488 and T47. Based on the phylogetic and phenotypic findings, a new genus and species, Armatimonas rosea gen. nov., sp. nov., is proposed for the isolate (type strain YO-36(T) ?=?NBRC 105658(T) ?=?DSM 23562(T)). In addition, a new bacterial phylum named Armatimonadetes phyl. nov. is proposed for the candidate phylum OP10 represented by A. rosea gen. nov., sp. nov. and Armatimonadaceae fam. nov., Armatimonadales ord. nov., and Armatimonadia classis nov. PMID:20622056

Tamaki, Hideyuki; Tanaka, Yasuhiro; Matsuzawa, Hiroaki; Muramatsu, Mizuho; Meng, Xian-Ying; Hanada, Satoshi; Mori, Kazuhiro; Kamagata, Yoichi

2011-06-01

72

Distinctive archaebacterial species associated with anaerobic rumen protozoan Entodinium caudatum  

Microsoft Academic Search

The diversity of archaebacteria associated with anaerobic rumen protozoan Entodinium caudatum in long term in vitro culture was investigated by denaturing gradient gel electrophoresis (DGGE) analysis of hypervariable V3 region of archaebacterial\\u000a 16S rRNA gene. PCR was accomplished directly from DNA extracted from a single protozoal cell and from total community genomic\\u000a DNA and the obtained fingerprints were compared. The

T. Tóthová; M. Piknová; S. Kišidayová; P. Javorský; P. Pristaš

2008-01-01

73

Gene Discovery by EST Sequencing in Toxoplasma gondii Reveals Sequences Restricted to the Apicomplexa  

Microsoft Academic Search

To accelerate gene discovery and facilitate genetic mapping in the protozoan parasite Toxoplasma gondii, we have generated >7000 new ESTs from the 58 ends of randomly selected tachyzoite cDNAs. Comparison of the ESTs with the existing gene databases identified possible functions for more than 500 new T. gondii genes by virtue of sequence motifs shared with conserved protein families, including

James W. Ajioka; John C. Boothroyd; Brian P. Brunk; Adrian Hehl; Ledeana Hillier; Ian D. Manger; Marco Marra; G. Christian Overton; David S. Roos; Kiew-Lian Wan; Robert Waterston; L. David Sibley

1998-01-01

74

The First Complete Genome Sequence of the Class Fimbriimonadia in the Phylum Armatimonadetes  

PubMed Central

In this study, we present the complete genome of Fimbriimonas ginsengisoli Gsoil 348T belonging to the class Fimbriimonadia of the phylum Armatimonadetes, formerly called as candidate phylum OP10. The complete genome contains a single circular chromosome of 5.23 Mb including a 45.5 kb prophage. Of the 4820 open reading frames (ORFs), 3,000 (62.2%) genes could be classified into Clusters of Orthologous Groups (COG) families. With the split of rRNA genes, strain Gsoil 348T had no typical 16S-23S-5S ribosomal RNA operon. In this genome, the GC skew inversion which was usually observed in archaea was found. The predicted gene functions suggest that the organism lacks the ability to synthesize histidine, and the TCA cycle is incomplete. Phylogenetic analyses based on ribosomal proteins indicated that strain Gsoil 348T represents a deeply branching lineage of sufficient divergence with other phyla, but also strongly involved in superphylum Terrabacteria.

Im, Wan-Taek; Wang, Sheng-Yue; Zhao, Guo-Ping; Zheng, Hua-Jun; Quan, Zhe-Xue

2014-01-01

75

Phylogenetic Framework and Molecular Signatures for the Main Clades of the Phylum Actinobacteria  

PubMed Central

Summary: The phylum Actinobacteria harbors many important human pathogens and also provides one of the richest sources of natural products, including numerous antibiotics and other compounds of biotechnological interest. Thus, a reliable phylogeny of this large phylum and the means to accurately identify its different constituent groups are of much interest. Detailed phylogenetic and comparative analyses of >150 actinobacterial genomes reported here form the basis for achieving these objectives. In phylogenetic trees based upon 35 conserved proteins, most of the main groups of Actinobacteria as well as a number of their superageneric clades are resolved. We also describe large numbers of molecular markers consisting of conserved signature indels in protein sequences and whole proteins that are specific for either all Actinobacteria or their different clades (viz., orders, families, genera, and subgenera) at various taxonomic levels. These signatures independently support the existence of different phylogenetic clades, and based upon them, it is now possible to delimit the phylum Actinobacteria (excluding Coriobacteriia) and most of its major groups in clear molecular terms. The species distribution patterns of these markers also provide important information regarding the interrelationships among different main orders of Actinobacteria. The identified molecular markers, in addition to enabling the development of a stable and reliable phylogenetic framework for this phylum, also provide novel and powerful means for the identification of different groups of Actinobacteria in diverse environments. Genetic and biochemical studies on these Actinobacteria-specific markers should lead to the discovery of novel biochemical and/or other properties that are unique to different groups of Actinobacteria.

Gao, Beile

2012-01-01

76

Distribution and culturability of the uncultivated ‘AGG58 cluster’ of the Bacteroidetes phylum in aquatic environments  

Microsoft Academic Search

Members of the Bacteroidetes phylum are abundant in aquatic habitats when assessed by fluorescent in situ hybridisation and in some 16S rRNA gene libraries. In this study 16S rRNA gene clone libraries were constructed with bacterial primers that amplify Bacteroidetes sequences well (27F, 1492R) from coastal seawater near Plymouth (UK) during a phytoplankton bloom. Most of the clones (66%, 106\\/160)

Louise A. O’Sullivan; Katherine E. Fuller; Ellen M. Thomas; Carol M. Turley; John C. Fry; Andrew J. Weightman

2004-01-01

77

A molecular phylogeny of the flagellated fungi (Chytridiomycota) and description of a new phylum (Blastocladiomycota)  

Microsoft Academic Search

Chytridiomycota (chytrids) is the only phylum of true Fungi that reproduces with motile spores (zoospores). Chytrids currently are classified into five orders based on habitat, zoospore characters and life cycles. In this paper we estimate the phylogeny of the chytrids with DNA sequences from the ribosomal RNA operon (18S+5.8S+28S subunits). To our surprise the morphologically reduced para- sites Olpidium and

Timothy Y. James; Peter M. Letcher; Joyce E. Longcore; Sharon E. Mozley-Standridge; David Porter; Martha J. Powell; Gareth W. Griffith; R. Vilgalys

2006-01-01

78

Unravelling the genetic diversity of ruminal bacteria belonging to the CFB phylum  

Microsoft Academic Search

Molecular biology approaches were employed to examine the genetic diversity of bacteria from the Cytophaga\\/Flexibacter\\/Bacteroides (CFB) phylum in the rumen of cattle. By this means we were able to identify cultured strains that represent some of the larger CFB clusters previously identified only by PCR amplification and sequencing. Complete 16S rDNA sequences were obtained for 16 previously isolated rumen strains,

Andreja Ramšak; Matjaž Peterka; Kiyoshi Tajima; Jenny C. Martin; Jacqueline Wood; Moira E. A. Johnston; Roustam I. Aminov; Harry J. Flint; Gorazd Avguštin

2000-01-01

79

Phylum-wide general protein O-glycosylation system of the Bacteroidetes  

PubMed Central

Summary The human gut symbiont Bacteroides fragilis has a general protein O-glycosylation system in which numerous extracytoplasmic proteins are glycosylated at a three amino acid motif. In B. fragilis, protein glycosylation is a fundamental and essential property as mutants with protein glycosylation defects have impaired growth and are unable to competitively colonize the mammalian intestine. In this study, we analyzed the phenotype of B. fragilis mutants with defective protein glycosylation and found that the glycan added to proteins is comprised of a core glycan and an outer glycan. The genetic region encoding proteins for the synthesis of the outer glycan is conserved within a Bacteroides species but divergent between species. Unlike the outer glycan, an antiserum raised to the core glycan reacted with all Bacteroidetes species tested, from all four classes of the phylum. We found that these diverse Bacteroidetes species synthesize numerous glycoproteins and glycosylate proteins at the same three amino acid motif. The wide-spread conservation of this protein glycosylation system within the phylum suggests that this system of post-translational protein modification evolved early, before the divergence of the four classes of Bacteroidetes, and has been maintained due to its physiologic importance to the diverse species of this phylum.

Coyne, Michael J.; Fletcher, C. Mark; Chatzidaki-Livanis, Maria; Posch, Gerald; Schaffer, Christina; Comstock, Laurie E.

2013-01-01

80

Gliding motility and Por secretion system genes are widespread among members of the phylum bacteroidetes.  

PubMed

The phylum Bacteroidetes is large and diverse, with rapid gliding motility and the ability to digest macromolecules associated with many genera and species. Recently, a novel protein secretion system, the Por secretion system (PorSS), was identified in two members of the phylum, the gliding bacterium Flavobacterium johnsoniae and the nonmotile oral pathogen Porphyromonas gingivalis. The components of the PorSS are not similar in sequence to those of other well-studied bacterial secretion systems. The F. johnsoniae PorSS genes are a subset of the gliding motility genes, suggesting a role for the secretion system in motility. The F. johnsoniae PorSS is needed for assembly of the gliding motility apparatus and for secretion of a chitinase, and the P. gingivalis PorSS is involved in secretion of gingipain protease virulence factors. Comparative analysis of 37 genomes of members of the phylum Bacteroidetes revealed the widespread occurrence of gliding motility genes and PorSS genes. Genes associated with other bacterial protein secretion systems were less common. The results suggest that gliding motility is more common than previously reported. Microscopic observations confirmed that organisms previously described as nonmotile, including Croceibacter atlanticus, "Gramella forsetii," Paludibacter propionicigenes, Riemerella anatipestifer, and Robiginitalea biformata, exhibit gliding motility. Three genes (gldA, gldF, and gldG) that encode an apparent ATP-binding cassette transporter required for F. johnsoniae gliding were absent from two related gliding bacteria, suggesting that the transporter may not be central to gliding motility. PMID:23123910

McBride, Mark J; Zhu, Yongtao

2013-01-01

81

Genome analysis of Elusimicrobium minutum, the first cultivated representative of the Elusimicrobia phylum (formerly Termite Group 1)  

Microsoft Academic Search

The candidate phylum Termite group 1 (TG1), is regularly 1 encountered in termite hindguts but is present also in many other habitats. Here we report the complete genome sequence (1.64 Mbp) of Elusimicrobium minutum strain Pei191{sup T}, the first cultured representative of the TG1 phylum. We reconstructed the metabolism of this strictly anaerobic bacterium isolated from a beetle larva gut

D. P. R. Herlemann; O. Geissinger; W. Ikeda-Ohtsubo; V. Kunin; H. Sun; A. Lapidus; P. Hugenholtz; A. Brune

2009-01-01

82

Constructed wetlands--Are they safe in reducing protozoan parasites?  

PubMed

Constructed wetlands have been promoted in recent literature for use in rural communities in developed as well as in developing countries as an appropriate technology to be handled with low operational maintenance costs. Within a joint project supported by BMBF (Project No O2WA0107 and No 02WA0108) research was done concerning the sanitation effect of constructed wetlands on wastewater effluents. This article will focus on the detection and the removal of cysts of Cryptosporidium parvum and Giarda lamblia, those being the most frequently identified pathogenic protozoan parasites worldwide with increasing medical and economical consequences. Two plants, one installed in 2000 as a pilot plant at Langenreichenbach near Leipzig (Saxony, Germany), the other one in routine operation since 1993 in a training center at the town of Belzig (Brandenburg, Germany) were tested for three years. Detection methods from the US EPA (ICR Protozoan Method for Detecting Giardia Cysts and Cryptosporidium Oocysts in Water by a Fluorescent Antibody Procedure (EPA/814-B-95-003;US EPA 1995) were employed in order to assess protozoal and bacterial reduction in the wastewater passing through different combinations of filter beds and fillings. Removal of cysts of Cryptosporidium and Giardia spp. turned out to be a 2 log reduction in all plants. The most effective structural element was a two-stage combination of filter beds leading to the highest removal efficiency both for the protozoan and the bacterial indicator organisms. Also, washed sand (0-2mm grain size) in the filter bed proved to be most effective filter material; the planted reed (phragmites spp.) or willow (salix spp.), however, turned out to be of minor importance for the filtering activity. PMID:20045664

Redder, Andreas; Dürr, Matthias; Daeschlein, Georg; Baeder-Bederski, Oliver; Koch, Christoph; Müller, Roland; Exner, Martin; Borneff-Lipp, Marianne

2010-01-01

83

RNA Interference in Protozoan Parasites: Achievements and Challenges ?  

PubMed Central

Protozoan parasites that profoundly affect mankind represent an exceptionally diverse group of organisms, including Plasmodium, Toxoplasma, Entamoeba, Giardia, trypanosomes, and Leishmania. Despite the overwhelming impact of these parasites, there remain many aspects to be discovered about mechanisms of pathogenesis and how these organisms survive in the host. Combined with the ever-increasing availability of sequenced genomes, RNA interference (RNAi), discovered a mere 13 years ago, has enormously facilitated the analysis of gene function, especially in organisms that are not amenable to classical genetic approaches. Here we review the current status of RNAi in studies of parasitic protozoa, with special emphasis on its use as a postgenomic tool.

Kolev, Nikolay G.; Tschudi, Christian; Ullu, Elisabetta

2011-01-01

84

Disseminated granulomas caused by an unidentified protozoan in sandhill cranes  

USGS Publications Warehouse

Oral granulomas were observed in 31 (33%) of 95 captive sandhill cranes (Grus canadensis) at the Patuxent Wildlife Research Center. Necropsy of six of the afflicted cranes revealed granulomatous nodules throughout many of their organ systems. Intracellular protozoan organisms morphologically resembling schizogonic stages were observed within the granulomas by light and electron microscopy. Sexual and asexual stages of coccidia were seen in sections of the intestines of 4 of 5 cranes examined microscopically, and Eimerian oocysts were seen in fecal flotation specimens from 3 of 4 birds.

Carpenter, J.W.; Spraker, T.R.; Gardiner, C.H.; Novilla, M.N.

1979-01-01

85

Vertebrate Cell Cycle Modulates Infection by Protozoan Parasites  

NASA Astrophysics Data System (ADS)

Synchronized HeLa cell populations were exposed to Trypanosoma cruzi or Toxoplasma gondii, obligate intracellular protozoan parasites that cause Chagas' disease and toxoplasmosis, respectively, in humans. The ability of the two parasites to infect HeLa cells increased as the HeLa cells proceeded from the G1 phase to the S phase of their growth cycle and decreased as the cells entered G2-M. Characterization of the S-phase cell surface components responsible for this phenomenon could be beneficial in the development of vaccines against these parasitic diseases.

Dvorak, James A.; Crane, Mark St. J.

1981-11-01

86

Parasite Mitogen-Activated Protein Kinases as Drug Discovery Targets to Treat Human Protozoan Pathogens  

PubMed Central

Protozoan pathogens are a highly diverse group of unicellular organisms, several of which are significant human pathogens. One group of protozoan pathogens includes obligate intracellular parasites such as agents of malaria, leishmaniasis, babesiosis, and toxoplasmosis. The other group includes extracellular pathogens such as agents of giardiasis and amebiasis. An unfortunate unifying theme for most human protozoan pathogens is that highly effective treatments for them are generally lacking. We will review targeting protozoan mitogen-activated protein kinases (MAPKs) as a novel drug discovery approach towards developing better therapies, focusing on Plasmodia, Leishmania, and Toxoplasma, about which the most is known.

Brumlik, Michael J.; Pandeswara, Srilakshmi; Ludwig, Sara M.; Murthy, Kruthi; Curiel, Tyler J.

2011-01-01

87

Chitinase Dependent Control of Protozoan Cyst Burden in the Brain  

PubMed Central

Chronic infections represent a continuous battle between the host's immune system and pathogen replication. Many protozoan parasites have evolved a cyst lifecycle stage that provides it with increased protection from environmental degradation as well as endogenous host mechanisms of attack. In the case of Toxoplasma gondii, these cysts are predominantly found in the immune protected brain making clearance of the parasite more difficult and resulting in a lifelong infection. Currently, little is known about the nature of the immune response stimulated by the presence of these cysts or how they are able to propagate. Here we establish a novel chitinase-dependent mechanism of cyst control in the infected brain. Despite a dominant Th1 immune response during Toxoplasma infection there exists a population of alternatively activated macrophages (AAMØ) in the infected CNS. These cells are capable of cyst lysis via the production of AMCase as revealed by live imaging, and this chitinase is necessary for protective immunity within the CNS. These data demonstrate chitinase activity in the brain in response to a protozoan pathogen and provide a novel mechanism to facilitate cyst clearance during chronic infections.

Nance, J. Philip; Vannella, Kevin M.; Worth, Danielle; David, Clement; Carter, David; Noor, Shahani; Hubeau, Cedric; Fitz, Lori; Lane, Thomas E.; Wynn, Thomas A.; Wilson, Emma H.

2012-01-01

88

Protozoan HSP90-Heterocomplex: Molecular Interaction Network and Biological Significance.  

PubMed

The HSP90 chaperone is a highly conserved protein from bacteria to higher eukaryotes. In eukaryotes, this chaperone participates in different large complexes, such as the HSP90 heterocomplex, which has important biological roles in cell homeostasis and differentiation. The HSP90-heterocomplex is also named the HSP90/HSP70 cycle because different co-chaperones (HIP, HSP40, HOP, p23, AHA1, immunophilins, PP5) participate in this complex by assembling sequentially, from the early to the mature complex. In this review, we analyze the conservation and relevance of HSP90 and the HSP90-heterocomplex in several protozoan parasites, with emphasis in Plasmodium spp., Toxoplasma spp., Leishmania spp. and Trypanosoma spp. In the last years, there has been an outburst of studies based on yeast two-hybrid methodology, co-immunoprecipitation-mass spectrometry and bioinformatics, which have generated a most comprehensive protein-protein interaction (PPI) network of HSP90 and its co-chaperones. This review analyzes the existing PPI networks of HSP90 and its co-chaperones of some protozoan parasites and discusses the usefulness of these powerful tools to analyze the biological role of the HSP90-heterocomplex in these parasites. The generation of a T. gondii HSP90 heterocomplex PPI network based on experimental data and a recent Plasmodium HSP90 heterocomplex PPI network are also included and discussed. As an example, the putative implication of nuclear transport and chromatin (histones and Sir2) as HSP90-heterocomplex interactors is here discussed. PMID:24694366

Figueras, Maria J; Echeverria, Pablo C; Angel, Sergio O

2014-05-01

89

The roles of intramembrane proteases in protozoan parasites.  

PubMed

Intramembrane proteolysis is widely conserved throughout different forms of life, with three major types of proteases being known for their ability to cleave peptide bonds directly within the transmembrane domains of their substrates. Although intramembrane proteases have been extensively studied in humans and model organisms, they have only more recently been investigated in protozoan parasites, where they turn out to play important and sometimes unexpected roles. Signal peptide peptidases are involved in endoplasmic reticulum (ER) quality control and signal peptide degradation from exported proteins. Recent studies suggest that repurposing inhibitors developed for blocking presenilins may be useful for inhibiting the growth of Plasmodium, and possibly other protozoan parasites, by blocking signal peptide peptidases. Rhomboid proteases, originally described in the fly, are also widespread in parasites, and are especially expanded in apicomplexans. Their study in parasites has revealed novel roles that expand our understanding of how these proteases function. Within this diverse group of parasites, rhomboid proteases contribute to processing of adhesins involved in attachment, invasion, intracellular replication, phagocytosis, and immune evasion, placing them at the vertex of host-parasite interactions. This article is part of a Special Issue entitled: Intramembrane Proteases. PMID:24099008

Sibley, L David

2013-12-01

90

Eimeria maxima phosphatidylinositol 4-phosphate 5-kinase: locus sequencing, characterization, and cross-phylum comparison  

Microsoft Academic Search

Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) may play an important role in host-cell invasion by the Eimeria species, protozoan parasites which can cause severe intestinal disease in livestock. Here, we report the structural organization\\u000a of the PIP5K gene in Eimeria maxima (Weybridge strain). Two E. maxima BAC clones carrying the E. maxima PIP5K (EmPIP5K) coding sequences were selected for shotgun sequencing, yielding

Mei-Yen Goh; Mei-Zhen Pan; Damer P. Blake; Kiew-Lian Wan; Beng-Kah Song

2011-01-01

91

Distribution and culturability of the uncultivated 'AGG58 cluster' of the Bacteroidetes phylum in aquatic environments.  

PubMed

Members of the Bacteroidetes phylum are abundant in aquatic habitats when assessed by fluorescent in situ hybridisation and in some 16S rRNA gene libraries. In this study 16S rRNA gene clone libraries were constructed with bacterial primers that amplify Bacteroidetes sequences well (27F, 1492R) from coastal seawater near Plymouth (UK) during a phytoplankton bloom. Most of the clones (66%, 106/160) affiliated with the Bacteroidetes phylum, and of these 62% (66/106; or 41% 66/160 of the entire library) clustered with marine bacterioplankton clones env.agg58, Arctic97A-17, CF17, CF96 and CF101. This phylogenetic branch of Bacteroidetes was designated the 'AGG58 cluster', and its presence in various aquatic environments was investigated. Two pairs of AGG58-specific 16S rRNA-gene-targeted polymerase chain reaction (PCR) primers were designed and successfully used to detect the cluster in DNA extracts from three UK coastal seawater sites, and from freshwater River Taff epilithon. In addition, 600 putative Bacteroidetes strains were isolated from these sites on relatively high-nutrient agar media. AGG58 cluster specific probes were used to screen the amplified 16S rRNA gene products from the isolates, but no members of the AGG58 cluster were discovered. The least specific probe hybridised with one River Taff water isolate (RW262 NCIMB 13979) which formed a monophyletic group with the genera Crocinitomix, Brumimicrobium and Cryomorpha of the family Cryomorphaceae in the Bacteroidetes phylum. RW262 probably represents the first isolate of a new genus within this family. This study provides new evidence that the uncultivated AGG58 group is abundant, globally distributed, and can be rapidly detected with the new PCR primers described. PMID:19712324

O'Sullivan, Louise A; Fuller, Katherine E; Thomas, Ellen M; Turley, Carol M; Fry, John C; Weightman, Andrew J

2004-03-01

92

Epibiont protozoan communities on Caridina lanceolata (Crustacea, Decapoda) from the Malili lakes of Sulawesi (Indonesia)  

Microsoft Academic Search

The epibiont protozoan communities living on the freshwater shrimp Caridina lanceolata Woltereck, 1937a from the three major lakes (Towuti, Matano and Mahalona) of the Malili lake system (Sulawesi, Indonesia) were studied. The number of epibionts varied between 2 and 971 per shrimp. Seven protozoan ciliate species were found: Acineta sulawesiensis n. sp., Cothurnia sp., Zoothamnium sp. (in all three lakes),

Gregorio Fernandez-Leborans; Kristina Zitzler; Regina Gabilondo

2006-01-01

93

Molecular Characterization of a Protozoan Parasite Target Antigen Recognized by Nonspecific Cytotoxic Cells  

Microsoft Academic Search

The target cell antigen(s) on tumor cells and on protozoan parasites recognized by NK and nonspecific cytotoxic cells (NCC) has not yet been specifically identified. NCC may be the teleost equivalent of NK cells and IL-2-activated NK cells. A ligand recognized by NCC has been identified. It is expressed on both protozoan parasites and mammalian tumor target cells. In the

Liliana Jaso-Friedmann; John H. Leary; Jaimie Warren; Royal A. McGraw; Donald L. Evans

1997-01-01

94

Influence of texture on habitable pore space and bacterial-protozoan populations in soil  

Microsoft Academic Search

Soil texture affects pore space, and bacterial and protozoan populations in soil. In the present study we tested the hypothesis that bacteria are more protected from protozoan predation in fine-textured soils than in coarse-textured soils because they have a larger volume of protected pore space available to them. The experiment consisted of three sterilized Orthic Black Chernozemic soils (silty clay,

P. M. Rutherford; N. G. Juma

1992-01-01

95

First Cultivation and Ecological Investigation of a Bacterium Affiliated with the Candidate Phylum OP5 from Hot Springs ?  

PubMed Central

The phylogenetic group termed OP5 was originally discovered in the Yellowstone National Park hot spring and proposed as an uncultured phylum; the group was afterwards analyzed by applying culture-independent approaches. Recently, a novel thermophilic chemoheterotrophic filamentous bacterium was obtained from a hot spring in Japan that was enriched through various isolation procedures. Phylogenetic analyses of the isolate have revealed that it is closely related to the OP5 phylum that has mainly been constructed with the environmental clones retrieved from thermophilic and mesophilic anaerobic environments. It appears that the lineage is independent at the phylum level in the domain Bacteria. Therefore, we designed a primer set for the 16S rRNA gene to specifically target the OP5 phylum and performed quantitative field analysis by using the real-time PCR method. Thus, the 16S rRNA gene of the OP5 phylum was detected in some hot-spring samples with the relative abundance ranging from 0.2% to 1.4% of the prokaryotic organisms detected. The physiology of the above-mentioned isolate and the related environmental clones indicated that they are scavengers contributing to the sulfur cycle in nature.

Mori, Koji; Sunamura, Michinari; Yanagawa, Katsunori; Ishibashi, Jun-ichiro; Miyoshi, Youko; Iino, Takao; Suzuki, Ken-ichiro; Urabe, Tetsuro

2008-01-01

96

Therapy of vector-borne protozoan infections in nonendemic settings.  

PubMed

Vector-borne protozoan infections are responsible for a wide variety of illnesses (mainly malaria, trypanosomiasis and leishmaniasis) affecting tropical and subtropical areas, but increasingly diagnosed in nonendemic settings. This article summarizes the therapeutic developments for these conditions during the past decade and focuses specifically on treatment recommendations for returning travelers and migrants. The treatment of malaria has known the most spectacular improvements. Progress in the management of leishmaniasis and trypanosomiasis has also been substantial and includes introduction of new drugs into clinical practice, combinations of existing drugs, or new laboratory tools for treatment monitoring as well as extension of treatment indications to new groups of patients. Serious gaps still exist in terms of effectiveness and tolerance. Since the research pipeline is very limited for the coming 5-10 years, optimized combinations of existing drugs need to be urgently explored. PMID:21609269

Bottieau, Emmanuel; Vekemans, Marc; Van Gompel, Alfons

2011-05-01

97

Protozoan parasites of bivalve molluscs: literature follows culture.  

PubMed

Bivalve molluscs are key components of the estuarine environments as contributors to the trophic chain, and as filter -feeders, for maintaining ecosystem integrity. Further, clams, oysters, and scallops are commercially exploited around the world both as traditional local shellfisheries, and as intensive or semi-intensive farming systems. During the past decades, populations of those species deemed of environmental or commercial interest have been subject to close monitoring given the realization that these can suffer significant decline, sometimes irreversible, due to overharvesting, environmental pollution, or disease. Protozoans of the genera Perkinsus, Haplosporidium, Marteilia, and Bonamia are currently recognized as major threats for natural and farmed bivalve populations. Since their identification, however, the variable publication rates of research studies addressing these parasitic diseases do not always appear to reflect their highly significant environmental and economic impact. Here we analyzed the peer- reviewed literature since the initial description of these parasites with the goal of identifying potential milestone discoveries or achievements that may have driven the intensity of the research in subsequent years, and significantly increased publication rates. Our analysis revealed that after initial description of the parasite as the etiological agent of a given disease, there is a time lag before a maximal number of yearly publications are reached. This has already taken place for most of them and has been followed by a decrease in publication rates over the last decade (20- to 30- year lifetime in the literature). Autocorrelation analyses, however, suggested that advances in parasite purification and culture methodologies positively drive publication rates, most likely because they usually lead to novel molecular tools and resources, promoting mechanistic studies. Understanding these trends should help researchers in prioritizing research efforts for these and other protozoan parasites, together with their development as model systems for further basic and translational research in parasitic diseases. PMID:24955977

Fernández Robledo, José A; Vasta, Gerardo R; Record, Nicholas R

2014-01-01

98

Protozoan Parasites of Bivalve Molluscs: Literature Follows Culture  

PubMed Central

Bivalve molluscs are key components of the estuarine environments as contributors to the trophic chain, and as filter –feeders, for maintaining ecosystem integrity. Further, clams, oysters, and scallops are commercially exploited around the world both as traditional local shellfisheries, and as intensive or semi–intensive farming systems. During the past decades, populations of those species deemed of environmental or commercial interest have been subject to close monitoring given the realization that these can suffer significant decline, sometimes irreversible, due to overharvesting, environmental pollution, or disease. Protozoans of the genera Perkinsus, Haplosporidium, Marteilia, and Bonamia are currently recognized as major threats for natural and farmed bivalve populations. Since their identification, however, the variable publication rates of research studies addressing these parasitic diseases do not always appear to reflect their highly significant environmental and economic impact. Here we analyzed the peer– reviewed literature since the initial description of these parasites with the goal of identifying potential milestone discoveries or achievements that may have driven the intensity of the research in subsequent years, and significantly increased publication rates. Our analysis revealed that after initial description of the parasite as the etiological agent of a given disease, there is a time lag before a maximal number of yearly publications are reached. This has already taken place for most of them and has been followed by a decrease in publication rates over the last decade (20– to 30– year lifetime in the literature). Autocorrelation analyses, however, suggested that advances in parasite purification and culture methodologies positively drive publication rates, most likely because they usually lead to novel molecular tools and resources, promoting mechanistic studies. Understanding these trends should help researchers in prioritizing research efforts for these and other protozoan parasites, together with their development as model systems for further basic and translational research in parasitic diseases.

Fernandez Robledo, Jose A.; Vasta, Gerardo R.; Record, Nicholas R.

2014-01-01

99

Functional type 2 photosynthetic reaction centers found in the rare bacterial phylum Gemmatimonadetes.  

PubMed

Photosynthetic bacteria emerged on Earth more than 3 Gyr ago. To date, despite a long evolutionary history, species containing (bacterio)chlorophyll-based reaction centers have been reported in only 6 out of more than 30 formally described bacterial phyla: Cyanobacteria, Proteobacteria, Chlorobi, Chloroflexi, Firmicutes, and Acidobacteria. Here we describe a bacteriochlorophyll a-producing isolate AP64 that belongs to the poorly characterized phylum Gemmatimonadetes. This red-pigmented semiaerobic strain was isolated from a freshwater lake in the western Gobi Desert. It contains fully functional type 2 (pheophytin-quinone) photosynthetic reaction centers but does not assimilate inorganic carbon, suggesting that it performs a photoheterotrophic lifestyle. Full genome sequencing revealed the presence of a 42.3-kb-long photosynthesis gene cluster (PGC) in its genome. The organization and phylogeny of its photosynthesis genes suggests an ancient acquisition of PGC via horizontal transfer from purple phototrophic bacteria. The data presented here document that Gemmatimonadetes is the seventh bacterial phylum containing (bacterio)chlorophyll-based phototrophic species. To our knowledge, these data provide the first evidence that (bacterio)chlorophyll-based phototrophy can be transferred between distant bacterial phyla, providing new insights into the evolution of bacterial photosynthesis. PMID:24821787

Zeng, Yonghui; Feng, Fuying; Medová, Hana; Dean, Jason; Koblížek, Michal

2014-05-27

100

FROM INCIPIENT TO SUBSTANTIAL: EVOLUTION OF PLACENTOTROPHY IN A PHYLUM OF AQUATIC COLONIAL INVERTEBRATES  

PubMed Central

Matrotrophy has long been known in invertebrates, but it is still poorly understood and has never been reviewed. A striking example of matrotrophy (namely, placentotrophy) is provided by the Bryozoa, a medium-sized phylum of the aquatic colonial filter feeders. Here I report on an extensive anatomical study of placental analogues in 21 species of the bryozoan order Cheilostomata, offering the first review on matrotrophy among aquatic invertebrates. The first anatomical description of incipient placentotrophy in invertebrates is presented together with the evidence for multiple independent origins of placental analogues in this order. The combinations of contrasting oocytic types (macrolecithal or microlecithal) and various degrees of placental development and embryonic enlargement during incubation, found in different bryozoan species, are suggestive of a transitional series from the incipient to the substantial placentotrophy accompanied by an inverse change in oogenesis, a situation reminiscent of some vertebrates. It seems that matrotrophy could trigger the evolution of sexual zooidal polymorphism in some clades. The results of this study show that this phylum, with its wide variety of reproductive patterns, incubation devices, and types of the simple placenta-like systems, offers a promising model for studying parallel evolution of placentotrophy in particular, and matrotrophy in general.

Ostrovsky, Andrew N; Fairbairn, D

2013-01-01

101

A molecular phylogeny of the flagellated fungi (Chytridiomycota) and description of a new phylum (Blastocladiomycota).  

PubMed

Chytridiomycota (chytrids) is the only phylum of true Fungi that reproduces with motile spores (zoospores). Chytrids currently are classified into five orders based on habitat, zoospore characters and life cycles. In this paper we estimate the phylogeny of the chytrids with DNA sequences from the ribosomal RNA operon (18S+5.8S+28S subunits). To our surprise the morphologically reduced parasites Olpidium and Rozella comprise two entirely new, and separate, lineages on the fungal tree. Olpidium brassicae groups among the Zygomycota, and Rozella spp. are the earliest branch to diverge in the fungal kingdom. The phylogeny also suggests that Chytridiomycota is not monophyletic and there are four major lineages of chytrids: Rozella spp., Olpidium brassicae, the Blastocladiales and a "core chytrid clade" containing the remaining orders and families and the majority of flagellated fungi. Within the core chytrid group 11 subclades can be identified, each of which correlates well with zoospore ultrastructure or morphology. We provide a synopsis of each clade and its morphological circumscription. The Blastocladiales appears to be the sister taxon of most nonflagellated fungi. Based on molecular phylogenetic and ultrastructural characters this order is elevated to a phylum, the Blastocladiomycota. PMID:17486963

James, Timothy Y; Letcher, Peter M; Longcore, Joyce E; Mozley-Standridge, Sharon E; Porter, David; Powell, Martha J; Griffith, Gareth W; Vilgalys, Rytas

2006-01-01

102

Adhesion molecules and other secreted host-interaction determinants in Apicomplexa: insights from comparative genomics.  

PubMed

Apicomplexa have developed distinctive adaptations for invading and surviving within animal cells. Here a synthetic overview of the diversity and evolutionary history of cell membrane-associated, -secreted, and -exported proteins related to apicomplexan parasitism is presented. A notable feature in this regard was the early acquisition of adhesion protein domains and glycosylation systems through lateral transfer from animals. These were utilized in multiple contexts, including invasion of host cells and parasite-specific developmental processes. Apicomplexans possess a specialized version of the ancestral alveolate extrusion machinery, the rhoptries and micronemes, which are deployed in invasion and delivery of proteins into host cells. Each apicomplexan lineage has evolved a unique spectrum of extruded proteins that modify host molecules in diverse ways. Hematozoans, in particular, appear to have evolved novel systems for export of proteins into the host organelles and cell membrane during intracellular development. These exported proteins are an important aspect of the pathogenesis of Plasmodium and Theileria, being involved in response to fever and in leukocyte proliferation respectively. The complement of apicomplexan surface proteins has primarily diversified via massive lineage-specific expansions of certain protein families, which are often coded by subtelomeric gene arrays. Many of these families have been found to be central to immune evasion. Domain shuffling and accretion have resulted in adhesins with new domain architectures. In terms of individual genes, constant selective pressures from the host immune response has resulted in extensive protein polymorphisms and gene losses. Apicomplexans have also evolved complex regulatory mechanisms controlling expression and maturation of surface proteins at the chromatin, transcriptional, posttranscriptional, and posttranslational levels. Evolutionary reconstruction suggests that the ancestral apicomplexan had thrombospondin and EGF domain adhesins, which were linked to the parasite cytoskeleton, and played a central role in invasion through formation of the moving junction. It also suggests that the ancestral parasite had O-linked glycosylation of surface proteins which was partially or entirely lost in hematozoan lineages. PMID:17631186

Anantharaman, Vivek; Iyer, Lakshminarayan M; Balaji, S; Aravind, L

2007-01-01

103

New species of Cryptosporidium Tyzzer, 1907 (Apicomplexa) from amphibian host: morphology, biology and phylogeny.  

PubMed

Cryptosporidium fragile sp. n. (Apicomplexa) is described from black-spined toads, Duttaphrynus melanostictus (Schneider) (Amphibia, Anura, Bufonidae) from the Malay Peninsula. The parasitized animals were directly imported from Malaysia and harboured C. fragile at the time of arrival. Oocysts were subspherical to elliptical with irregular contour in optical section, measuring 6.2 (5.5-7.0) x 5.5 (5.0-6.5) microm. Oocyst wall was smooth and colourless in light microscopy. The endogenous development of C. fragile in the stomach of black-spined toad was analysed in detail using light and electron microscopy. Cryptosporidian developmental stages were confined to the surface of gastric epithelial cells. In transmission experiments, C. fragile has not been infective for one fish species, four amphibian species, one species of reptile and SCID mice. Full length small subunit rRNA gene sequence was obtained. Phylogenetic reconstruction revealed distinct status of C. fragile within the clade of species with gastric localisation including Cryptosporidium muris Tyzzer, 1907, Cryptosporidium serpentis Levine, 1980 and Cryptosporidium andersoni Lindsay, Upton, Owens, Morgan, Mead et Blagburn, 2000. Described characteristics differentiate C. fragile from the currently recognized Cryptosporidium species. Our experience with the description of C. fragile has led us to revise the recommended criteria for an introduction of a new Cryptosporidium species name. C. fragile is the first species described and named from an amphibian host. Its prevalence of 83% (15/18) in black-spined toads within the 3 months after importation calls for strict quarantine measures and import regulation for lower vertebrates. PMID:18666410

Jirk?, Miloslav; Valigurová, Andrea; Koudela, Bretislav; Krízek, Jaroslav; Modrý, David; Slapeta, Jan

2008-06-01

104

Recent highlights in anti-protozoan drug development and resistance research  

PubMed Central

This article summarizes the highlights of research presented in January, 2012, at the Keystone Symposium on “Drug Discovery for Protozoan Parasites” held in Santa Fe, New Mexico. This symposium which convenes approximately every 2 years provides a forum for leading investigators around the world to present data covering basic sciences to clinical trials relating to anti-protozoan drug development and drug resistance. Many talks focused on malaria, but other protozoan diseases receiving attention included African sleeping sickness, Chagas disease, leishmaniasis, cryptosporidiosis, and amoebiasis. The new research, most of it unpublished, provided insights into the latest developments in the field.

Buckner, Frederick S.; Waters, Norman C.; Avery, Vicky M.

2012-01-01

105

Molecular diagnostics of Sarcocystis spp. infections.  

PubMed

Protozoa of the genus Sarcocystis (phylum Apicomplexa, family Sarcocystidae) is one of the most common parasites affecting animals. Interspecies diagnostic of Sarcocystis genus was based on electron microscopy for many years. Because of absence of visible differences between species with reachable magnifications, light microscopy is useless. In many cases serological diagnostic method have lack of sensitivity. A variety of molecular methods have been developed and used to detect and identify Sarcocystis spp. and to assess the genetic diversity among this protozoan from different population/hosts. Nowadays, molecular diagnostic is the common, time/cost effective method used all over the world to interspecies differentiation. PMID:23214385

Stojecki, K; Karamon, J; Sroka, J; Cencek, T

2012-01-01

106

Genome Sequence of Victivallis vadensis ATCC BAA-548, an Anaerobic Bacterium from the Phylum Lentisphaerae, Isolated from the Human Gastrointestinal Tract?  

PubMed Central

Victivallis vadensis ATCC BAA-548 represents the first cultured representative from the novel phylum Lentisphaerae, a deep-branching bacterial lineage. Few cultured bacteria from this phylum are known, and V. vadensis therefore represents an important organism for evolutionary studies. V. vadensis is a strictly anaerobic sugar-fermenting isolate from the human gastrointestinal tract.

van Passel, Mark W. J.; Kant, Ravi; Palva, Airi; Lucas, Susan; Copeland, Alex; Lapidus, Alla; Glavina del Rio, Tijana; Dalin, Eileen; Tice, Hope; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Davenport, Karen Walston; Sims, David; Brettin, Thomas S.; Detter, John C.; Han, Shunsheng; Larimer, Frank W.; Land, Miriam L.; Hauser, Loren; Kyrpides, Nikolaos; Ovchinnikova, Galina; Richardson, P. Paul; de Vos, Willem M.; Smidt, Hauke; Zoetendal, Erwin G.

2011-01-01

107

Genome sequence of Victivallis vadensis ATCC BAA-548, an anaerobic bacterium from the phylum Lentisphaerae, isolated from the human gastro-intestinal tract  

SciTech Connect

Victivallis vadensis ATCC BAA-548 represents the first cultured representative from the novel phylum Lentisphaerae, a deep-branching bacterial lineage. Few cultured bacteria from this phylum are known, and V. vadensis therefore represents an important organism for evolutionary studies. V. vadensis is a strictly anaerobic sugar-fermenting isolate from the human gastro-intestinal tract.

Van Passel, Mark W.J. [Wageningen University and Research Centre, The Netherlands; Kant, Ravi [University of Helsinki; Palva, Airi [University of Helsinki; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Glavina Del Rio, Tijana [U.S. Department of Energy, Joint Genome Institute; Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Davenport, Karen W. [Los Alamos National Laboratory (LANL); Sims, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Larimer, Frank W [ORNL; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Ovchinnikova, Galina [U.S. Department of Energy, Joint Genome Institute; Richardson, Paul [U.S. Department of Energy, Joint Genome Institute; De Vos, Willem M. [Wageningen University and Research Centre, The Netherlands; Smidt, Hauke [Wageningen University and Research Centre, The Netherlands; Zoetendal, Erwin G. [Wageningen University and Research Centre, The Netherlands

2011-01-01

108

Investigating the origins of triploblasty: `mesodermal' gene expression in a diploblastic animal, the sea anemone Nematostella vectensis (phylum, Cnidaria; class, Anthozoa)  

Microsoft Academic Search

Mesoderm played a crucial role in the radiation of the triploblastic Bilateria, permitting the evolution of larger and more complex body plans than in the diploblastic, non- bilaterian animals. The sea anemone Nematostella is a non- bilaterian animal, a member of the phylum Cnidaria. The phylum Cnidaria (sea anemones, corals, hydras and jellyfish) is the likely sister group of the

Mark Q. Martindale; Kevin Pang; John R. Finnerty

2004-01-01

109

From the Flavobacterium genus to the phylum Bacteroidetes: genomic analysis of dnd gene clusters.  

PubMed

Phosphorothioate modification of DNA and the corresponding DNA degradation (Dnd) phenotype that occurs during gel electrophoresis are caused by dnd genes. Although widely distributed among Bacteria and Archaea, dnd genes have been found in only very few, taxonomically unrelated, bacterial species so far. Here, we report the presence of dnd genes and their associated Dnd phenotype in two Flavobacterium species. Comparison with dnd gene clusters previously described led us to report a noncanonical genetic organization and to identify a gene likely encoding a hybrid DndE protein. Hence, we showed that dnd genes are also present in members of the family Flavobacteriaceae, a bacterial group occurring in a variety of habitats with an interesting diversity of lifestyle. Two main types of genomic organization of dnd loci were uncovered probably denoting their spreading in the phylum Bacteroidetes via distinct genetic transfer events. PMID:23965156

Barbier, Paul; Lunazzi, Aurélie; Fujiwara-Nagata, Erina; Avendaño-Herrera, Ruben; Bernardet, Jean-François; Touchon, Marie; Duchaud, Eric

2013-11-01

110

Genomic analysis of Chthonomonas calidirosea, the first sequenced isolate of the phylum Armatimonadetes.  

PubMed

Most of the lineages of bacteria have remained unknown beyond environmental surveys using molecular markers. Until the recent characterisation of several strains, the phylum Armatimonadetes (formerly known as 'candidate division OP10') was a dominant and globally-distributed lineage within this 'uncultured majority'. Here we report the first Armatimonadetes genome from the thermophile Chthonomonas calidirosea T49(T) and its role as a saccharide scavenger in a geothermal steam-affected soil environment. Phylogenomic analysis indicates T49(T) to be related closely to the phylum Chloroflexi. The predicted genes encoding for carbohydrate transporters (27 carbohydrate ATP-binding cassette transporter-related genes) and carbohydrate-metabolising enzymes (including at least 55 putative enzymes with glycosyl hydrolase domains) within the 3.43?Mb genome help explain its ability to utilise a wide range of carbohydrates as well as its inability to break down extracellular cellulose. The presence of only a single class of branched amino acid transporter appears to be the causative step for the requirement of isoleucine for growth. The genome lacks many commonly conserved operons (for example, lac and trp). Potential causes for this, such as dispersion of functionally related genes via horizontal gene transfer from distant taxa or recent genome recombination, were rejected. Evidence suggests T49(T) relies on the relatively abundant ?-factors, instead of operonic organisation, as the primary means of transcriptional regulation. Examination of the genome with physiological data and environmental dynamics (including interspecific interactions) reveals ecological factors behind the apparent elusiveness of T49(T) to cultivation and, by extension, the remaining 'uncultured majority' that have so far evaded conventional microbiological techniques. PMID:24477196

Lee, Kevin C-Y; Morgan, Xochitl C; Dunfield, Peter F; Tamas, Ivica; McDonald, Ian R; Stott, Matthew B

2014-07-01

111

"Endomicrobia": Cytoplasmic Symbionts of Termite Gut Protozoa Form a Separate Phylum of Prokaryotes  

PubMed Central

Lignocellulose digestion by wood-feeding termites depends on the mutualistic interaction of unusual, flagellate protists located in their hindgut. Most of the flagellates harbor numerous prokaryotic endosymbionts of so-far-unknown identity and function. Using a full-cycle molecular approach, we show here that the endosymbionts of the larger gut flagellates of Reticulitermes santonensis belong to the so-called termite group 1 (TG-1) bacteria, a group of clones previously obtained exclusively from gut homogenates of Reticulitermes speratus that are only distantly related to other bacteria and are considered a novel bacterial phylum based on their 16S rRNA gene sequences. Fluorescence in situ hybridization with specifically designed oligonucleotide probes confirmed that TG-1 bacteria are indeed located within the flagellate cells and demonstrated that Trichonympha agilis (Hypermastigida) and Pyrsonympha vertens (Oxymonadida) harbor phylogenetically distinct populations of symbionts (<95% sequence similarity). Transmission electron microscopy revealed that the symbionts are small, spindle-shaped cells (0.6 ?m in length and 0.3 ?m in diameter) surrounded by two membranes and located within the cytoplasm of their hosts. The symbionts of the two flagellates are described as candidate species in the candidate genus “Endomicrobium.” Moreover, we provide evidence that the members of the TG-1 phylum, for which we propose the candidate name “Endomicrobia,” are phylogenetically extremely diverse and are present in and also restricted to the guts of all lower termites and wood-feeding cockroaches of the genus Cryptocercus, the only insects that are in an exclusive, obligately mutualistic association with such unique cellulose-fermenting protists.

Stingl, Ulrich; Radek, Renate; Yang, Hong; Brune, Andreas

2005-01-01

112

ProtozoaDB: dynamic visualization and exploration of protozoan genomes  

PubMed Central

ProtozoaDB (http://www.biowebdb.org/protozoadb) is being developed to initially host both genomics and post-genomics data from Plasmodium falciparum, Entamoeba histolytica, Trypanosoma brucei, T. cruzi and Leishmania major, but will hopefully host other protozoan species as more genomes are sequenced. It is based on the Genomics Unified Schema and offers a modern Web-based interface for user-friendly data visualization and exploration. This database is not intended to duplicate other similar efforts such as GeneDB, PlasmoDB, TcruziDB or even TDRtargets, but to be complementary by providing further analyses with emphasis on distant similarities (HMM-based) and phylogeny-based annotations including orthology analysis. ProtozoaDB will be progressively linked to the above-mentioned databases, focusing in performing a multi-source dynamic combination of information through advanced interoperable Web tools such as Web services. Also, to provide Web services will allow third-party software to retrieve and use data from ProtozoaDB in automated pipelines (workflows) or other interoperable Web technologies, promoting better information reuse and integration. We also expect ProtozoaDB to catalyze the development of local and regional bioinformatics capabilities (research and training), and therefore promote/enhance scientific advancement in developing countries.

Davila, Alberto M. R.; Mendes, Pablo N.; Wagner, Glauber; Tschoeke, Diogo A.; Cuadrat, Rafael R. C.; Liberman, Felipe; Matos, Luciana; Satake, Thiago; Ocana, Kary A. C. S.; Triana, Omar; Cruz, Sergio M. S.; Juca, Henrique C. L.; Cury, Juliano C.; Silva, Fabricio N.; Geronimo, Guilherme A.; Ruiz, Margarita; Ruback, Eduardo; Silva, Floriano P.; Probst, Christian M.; Grisard, Edmundo C.; Krieger, Marco A.; Goldenberg, Samuel; Cavalcanti, Maria C. R.; Moraes, Milton O.; Campos, Maria L. M.; Mattoso, Marta

2008-01-01

113

Ciliary protein conservation during development in the ciliated protozoan, Oxytricha  

PubMed Central

The ciliated protozoan Oxytricha fallax possesses multiple highly localized clusters of basal bodies and cilia, all of which are broken down and rebuilt during prefission morphogenesis-with one major exception. The adoral zone of membranelles (AZM) of the ciliate oral apparatus contains approximately 1,500-2,000 basal bodies and cilia, and it is the only compound ciliary structure that is passed morphologically intact to one daughter cell at each cell division. By labeling all proteins in cells, and then picking the one daughter cell possessing the original labeled AZM, we could then evaluate whether or not the ciliary proteins of the AZM were diluted (i.e., either by degradation to constituent amino acids or by subunit exchange) during cell division. Autoradiographic analysis demonstrated that the label was highly conserved in the AZM (i.e., we saw no evidence of turnover), and electrophoretic data illustrate that at least one of the proteins of the AZM is tubulin. We, therefore, conclude that for at least some of the ciliary and basal body proteins of Oxytricha fallax, AZM morphological conservation is essentially equivalent to molecular conservation.

1987-01-01

114

Description of Fimbriimonas ginsengisoli gen. nov., sp. nov. within the Fimbriimonadia class nov., of the phylum Armatimonadetes.  

PubMed

Strain Gsoil 348(T) was isolated from a ginseng field soil sample by selecting micro-colonies from one-fifth strength modified R2A agar medium after a long incubation period. 16S rRNA gene sequence analysis indicated that the strain is related to members of the phylum Armatimonadetes (formerly called candidate phylum OP10). Strain Gsoil 348(T) is mesophilic, strictly aerobic, non-motile and rod-shaped. It only grows in low nutrient media. The major respiratory quinones are menaquinones MK-11 and MK-10, and the main fatty acids are iso-C(15:0), iso-C(17:0), C(16:0) and C(16:1) ?11c. The G+C content is 61.4 mol%. The 16S rRNA gene sequences in public databases belonging to the phylum Armatimonadetes were clustered here into 6 groups. Five of these groups constituted a coherent cluster distinct from the sequences of other phyla in phylogenetic trees that were constructed using multiple-outgroup sequences from 49 different phyla. On the basis of polyphasic taxonomic analyses, it is proposed that strain Gsoil 348(T) (= KACC 14959(T) = JCM 17079(T)) should be placed in Fimbriimonas ginsengisoli gen. nov., sp. nov., as the cultured representative of the Fimbriimonadia class. nov., corresponding with Group 4 of the phylum Armatimonadetes. PMID:22527625

Im, Wan-Taek; Hu, Zi-Ye; Kim, Kyoung-Ho; Rhee, Sung-Keun; Meng, Han; Lee, Sung-Taik; Quan, Zhe-Xue

2012-08-01

115

The role of extracellular vesicles in Plasmodium and other protozoan parasites.  

PubMed

Protozoan parasites and other microorganisms use various pathways to communicate within their own populations and to manipulate their outside environments, with the ultimate goal of balancing the rate of growth and transmission. In higher eukaryotes, including humans, circulating extracellular vesicles are increasingly recognized as key mediators of physiological and pathological processes. Recent evidence suggests that protozoan parasites, including those responsible for major human diseases such as malaria and Chagas disease, use similar machinery. Indeed, intracellular and extracellular protozoan parasites secrete extracellular vesicles to promote growth and induce transmission, to evade the host immune system, and to manipulate the microenvironment. In this review we will discuss the general pathways of extracellular vesicle biogenesis and their functions in protozoan infections. PMID:24406102

Mantel, Pierre-Yves; Marti, Matthias

2014-03-01

116

[Effect of reaction conditions on the removal of pathogenic protozoan from secondary effluent in flocculation process].  

PubMed

Cryptosporidium and Giardia in reclaimed water are endangering the health of human beings by direct and indirect ways. Compared with traditional disinfection measures, flocculation, clarification and filtration can remove the pathogenic protozoan from wastewater more effectively. The factors affecting the removal of pathogenic protozoan from secondary effluent in flocculation process, including type and dosage of flocculant, pH, temperature and other reaction conditions were studied. The experimental results showed that the effectiveness of pathogenic protozoan removal appeared to be good at pH 6 - 8 and bad at low temperature. The effectiveness increased with the increase of ferric chloride dosage. Aluminium sulphate and poly aluminium chloride gave better performance in removal of pathogenic protozoan at the dosage of 70 mg/L and 20 mg/L respectively. PMID:17926405

Zhang, Tong; Hu, Hong-Ying; Wu, Qian-Yuan; Zong, Zu-Sheng

2007-08-01

117

Blabericola rhyparobiae n. comb. (Apicomplexa: Eugregarinida: Blabericolidae), parasitizing the Madeira cockroach, Rhyparobia maderae (Dictyoptera: Blaberidae).  

PubMed

Blabericola rhyparobiae n. comb. (Apicomplexa: Eugregarinida: Blabericolidae) is redescribed from the Madeira cockroach, Rhyparobia maderae (Dictyoptera: Blaberidae: Oxyhaloinae: Nauphoetini). Oocysts within the genus are typically dolioform with nonprojecting polar plates. Those of B. rhyparobiae differ from all other species of Blabericola in being oblong rather than dolioform. Morphometrically, the oocysts of B. rhyparobiae are significantly narrower than those of any other known species in the genus; they are significantly longer than those of Blabericola haasi, Blabericola migrator, and Blabericola princisi, but they are significantly shorter than those of Blabericola cubensis (oocyst width 4.47 ?m vs. 4.74 ?m, 4.70 ?m, 5.06 ?m, 5.21 ?m, respectively; oocyst length 8.98 ?m vs. 7.94 ?m, 7.93 ?m, 8.85 ?m, 9.26 ?m, respectively). All 5 species are also distinguished by unique sporozoite-bearing cavity sizes and morphometric ratios. Gametocysts of Blabericola species are either orbicular (B. cubensis, B. princisi) or elliptoid (B. haasi , B. migrator, B. rhyparobiae). Among Blabericola species with elliptoid gametocysts, the gametocysts of B. rhyparobiae are intermediate in size relative to the much larger gametocysts of B. migrator and the much smaller gametocysts of B. haasi (gametocyst length 462.06 ?m vs. 728.11 ?m, 272.02 ?m; gametocyst width 297.12 ?m vs. 461.31 ?m, 178.36 ?m, respectively). No structurally unique feature of the gamont distinguishes among species of Blabericola, but gamonts of all 5 species differ morphometrically. Gamonts of B. rhyparobiae differ significantly from all other species in the genus in the primite's protomerite and deutomerite lengths, the satellite' deutomerite lengths, and the total length of both primite and satellite in association. The gamonts of B. rhyparobiae are significantly smaller than those of B. cubensis, B. migrator, and B. princisi but significantly larger than those of B. haasi and can be readily distinguished based on size alone (primite total length 460 ?m vs. 563 ?m, 800 ?m, 547 ?m, 316 ?m, respectively; satellite total length 419 ?m vs. 507 ?m, 695 ?m, 526 ?m, 298 ?m, respectively). PMID:23984856

Clopton, Richard E

2014-02-01

118

Parasites and malignancies, a review, with emphasis on digestive cancer induced by Cryptosporidium parvum (Alveolata: Apicomplexa)  

PubMed Central

The International Agency for Research on Cancer (IARC) identifies ten infectious agents (viruses, bacteria, parasites) able to induce cancer disease in humans. Among parasites, a carcinogenic role is currently recognized to the digenetic trematodes Schistosoma haematobium, leading to bladder cancer, and to Clonorchis sinensis or Opisthorchis viverrini, which cause cholangiocarcinoma. Furthermore, several reports suspected the potential association of other parasitic infections (due to Protozoan or Metazoan parasites) with the development of neoplastic changes in the host tissues. The present work shortly reviewed available data on the involvement of parasites in neoplastic processes in humans or animals, and especially focused on the carcinogenic power of Cryptosporidium parvum infection. On the whole, infection seems to play a crucial role in the etiology of cancer.

Benamrouz, S.; Conseil, V.; Creusy, C.; Calderon, E.; Dei-Cas, E.; Certad, G.

2012-01-01

119

Effects of bacterivorous ciliated protozoans on degradation efficiency of a petrochemical activated sludge process  

Microsoft Academic Search

The aim of this work was to adapt protozoans to a saline and crude-oil contaminated petrochemical sewage. Wild type protozoans were isolated from different marine locations and from a municipal-refinery mixed sewage treatment plant. In batch culture the micro-organisms were adapted by slowly increasing concentrations of sodium chloride and hydrocarbons. No wild type strain survived in the saline sewage. Using

Peter Holubar; Tanja Grudke; Andreas Moser; Birgit Strenn; Rudolf Braun

2000-01-01

120

Evolution of apoptosis-like programmed cell death in unicellular protozoan parasites  

Microsoft Academic Search

Apoptosis-like programmed cell death (PCD) has recently been described in multiple taxa of unicellular protists, including\\u000a the protozoan parasites Plasmodium, Trypanosoma and Leishmania. Apoptosis-like PCD in protozoan parasites shares a number of morphological features with programmed cell death in multicellular\\u000a organisms. However, both the evolutionary explanations and mechanisms involved in parasite PCD are poorly understood. Explaining\\u000a why unicellular organisms appear

Szymon Kaczanowski; Mohammed Sajid; Sarah E Reece

2011-01-01

121

Protozoan predation and the turnover of soil organic carbon and nitrogen in the presence of plants  

Microsoft Academic Search

The impact of protozoan grazing on the dynamics and mineralization of 14C- and 15N-labelled soil organic material was investigated in a microcosm experiment. Sterilized soil was planted with wheat and either inoculated with bacteria alone or with bacteria and protozoa or with bacteria and a 1:10 diluted protozoan inoculum. 14C-CO2 formation was continuously monitored. It served as an indicator of

P. J. Kuikman; A. G. Jansen; J. A. van Veen I; A. J. B. Zehnder

1990-01-01

122

Sequencing of the smallest Apicomplexan genome from the human pathogen Babesia microti.  

PubMed

We have sequenced the genome of the emerging human pathogen Babesia microti and compared it with that of other protozoa. B. microti has the smallest nuclear genome among all Apicomplexan parasites sequenced to date with three chromosomes encoding ?3500 polypeptides, several of which are species specific. Genome-wide phylogenetic analyses indicate that B. microti is significantly distant from all species of Babesidae and Theileridae and defines a new clade in the phylum Apicomplexa. Furthermore, unlike all other Apicomplexa, its mitochondrial genome is circular. Genome-scale reconstruction of functional networks revealed that B. microti has the minimal metabolic requirement for intraerythrocytic protozoan parasitism. B. microti multigene families differ from those of other protozoa in both the copy number and organization. Two lateral transfer events with significant metabolic implications occurred during the evolution of this parasite. The genomic sequencing of B. microti identified several targets suitable for the development of diagnostic assays and novel therapies for human babesiosis. PMID:22833609

Cornillot, Emmanuel; Hadj-Kaddour, Kamel; Dassouli, Amina; Noel, Benjamin; Ranwez, Vincent; Vacherie, Benoît; Augagneur, Yoann; Brès, Virginie; Duclos, Aurelie; Randazzo, Sylvie; Carcy, Bernard; Debierre-Grockiego, Françoise; Delbecq, Stéphane; Moubri-Ménage, Karina; Shams-Eldin, Hosam; Usmani-Brown, Sahar; Bringaud, Frédéric; Wincker, Patrick; Vivarès, Christian P; Schwarz, Ralph T; Schetters, Theo P; Krause, Peter J; Gorenflot, André; Berry, Vincent; Barbe, Valérie; Ben Mamoun, Choukri

2012-10-01

123

Isospora massardi sp. nov. (Apicomplexa: Eimeriidae) from the white-necked thrush Turdus albicollis (Passeriformes: Turdidae) from Brazil.  

PubMed

A new coccidian species (Protozoa: Apicomplexa: Eimeriidae) are reported from the white-necked thrush Turdus albicollis Vieillot, 1818, a very common species in South America. Isospora massardi sp. nov. oocysts are subspherical, 18.6 × 17.7 ?m, with smooth, bilayered wall, ?0.9 ?m. Micropyle, oocyst residuum are absent, but two polar granules are frequently present. Sporocysts are ovoidal, 14.8 × 9.3 ?m. Stieda body is knob-like to rounded and substieda body is rounded. Sporocyst residuum is composed of scattered spherules of different sizes. Sporozoites are vermiform with posterior and anterior refractile bodies and a nucleus. This is the sixth description of an isosporoid coccidium infecting a New World turdid bird. PMID:24827098

Lopes, Bruno do Bomfim; Berto, Bruno P; Luz, Hermes Ribeiro; Galvão, Gideão da Silva; Ferreira, Ildemar; Lopes, Carlos Wilson G

2014-06-01

124

Efficacy of some anticoccidial drugs for treating coccidial enteritis of the common carp caused by Goussia carpelli (Apicomplexa: Eimeriidae).  

PubMed

In this study, nine anticoccidial drugs commonly used in poultry were tested for efficacy for the prevention and treatment of Goussia carpelli (Apicomplexa) infection in common carp (Cyprinus carpio L.). To establish experimental infection with G. carpelli, paratenic host oligochaetes of the genera Tubifex and Limnodrilus were infected with oocysts, and laboratory-cultured parasite-free common carp fingerlings were infected by feeding to them oligochaetes containing sporozoites. The anticoccidial drugs (amprolium, narasin, maduramicin, salinomycin Na, lasalocid Na, diclazuril, robenidine HCl, monensin Na and toltrazuril), mixed in the food of the fish in a dose of 200 mg/kg, were fed for 12 days. Common carp fingerlings fed diclazuril, lasalocid, robenidine HCl or maduramicin and killed on day 14 after exposure were free from infection, while other groups treated with amprolium, toltrazuril, monensin Na, narasin or salinomycin Na harboured oocysts in the mucus and epithelium of the gut. PMID:17385557

Molnár, K; Ostoros, Györgyi

2007-03-01

125

Water-soluble ruthenium complexes bearing activity against protozoan parasites.  

PubMed

Parasitic illnesses are major causes of human disease and misery worldwide. Among them, both amebiasis and Chagas disease, caused by the protozoan parasites, Entamoeba histolytica and Trypanosoma cruzi, are responsible for thousands of annual deaths. The lack of safe and effective chemotherapy and/or the appearance of current drug resistance make the development of novel pharmacological tools for their treatment relevant. In this sense, within the framework of the medicinal inorganic chemistry, metal-based drugs appear to be a good alternative to find a pharmacological answer to parasitic diseases. In this work, novel ruthenium complexes [RuCl2(HL)(HPTA)2]Cl2 with HL = bioactive 5-nitrofuryl containing thiosemicarbazones and PTA?=?1,3,5-triaza-7-phosphaadamantane have been synthesized and fully characterized. PTA was included as co-ligand in order to modulate complexes aqueous solubility. In fact, obtained complexes were water soluble. Their activity against T. cruzi and E. histolytica was evaluated in vitro. [RuCl2(HL4)(HPTA)2]Cl2 complex, with HL4?=?N-phenyl-5-nitrofuryl-thiosemicarbazone, was the most active compound against both parasites. In particular, it showed an excellent activity against E. histolytica (half maximal inhibitory concentration (IC50)?=?5.2 ?M), even higher than that of the reference drug metronidazole. In addition, this complex turns out to be selective for E. histolytica (selectivity index (SI) >38). The potential mechanism of antiparasitic action of the obtained ruthenium complexes could involve oxidative stress for both parasites. Additionally, complexes could interact with DNA as second potential target by an intercalative-like mode. Obtained results could be considered a contribution in the search for metal compounds that could be active against multiple parasites. PMID:24740394

Sarniguet, Cynthia; Toloza, Jeannette; Cipriani, Micaella; Lapier, Michel; Vieites, Marisol; Toledano-Magaña, Yanis; García-Ramos, Juan Carlos; Ruiz-Azuara, Lena; Moreno, Virtudes; Maya, Juan Diego; Azar, Claudio Olea; Gambino, Dinorah; Otero, Lucía

2014-06-01

126

Gregarines on a Diet: The Effects of Host Starvation on Gregarina confusa Janovy et al., 2007 (Apicomplexa: Eugregarinida) in Tribolium destructor Uyttenboogaart, 1933 (Coleoptera: Tenebrionidae) Larvae  

Microsoft Academic Search

This study was designed to explore the nutritional relationship between Gregarina confusa (Apicomplexa: Eugregarinida) parasites and its coleopteran host, Tribolium destructor, by measuring the cytoplasmic density of gregarines in continuously fed larvae, starved larvae, and larvae refed after starvation. Cultures were maintained in a standard media (whole wheat flour:commercial wheat germ:yeast [30:10:1]). Larvae from control and experimental groups were dissected

Jodi Schreurs; Janovy John J. Jr

2008-01-01

127

Whole clam culture as a quantitative diagnostic procedure of Perkinsus atlanticus (Apicomplexa, Perkinsea) in clams Ruditapes decussatus  

Microsoft Academic Search

The protozoan parasite Perkinsus atlanticus (Azevedo, 1989) causes severe losses among cultured clams, Ruditapes decussatus. This parasite is routinely diagnosed by means of histology or incubation of gills in fluid thioglycollate medium. However, in order to develop models of experimental reproduction of the disease, a procedure for infection intensity evaluation was required. Thus, a diagnostic method has been developed, based

Manuela Almeida; Franck Berthe; Anne Thébault; Maria Teresa Dinis

1999-01-01

128

Antifilarial activity of Zoanthus species (Phylum Coelenterata, Class Anthzoa) against human lymphatic filaria, Brugia malayi.  

PubMed

The chloroform methanol (1:1) extract of an unidentified green zoanthus (Phylum Coelenterata, Class Anthozoa) showed promising in vitro adulticidal activity with a lethal concentration of 125 microg/ml on Brugia malayi. This extract brought about a 52.2% reduction in circulating microfilariae of B. malayi when administered to infected Mastomys coucha at 250 mg/kg, orally for 5 consecutive days. Further fractionation of the extract led to the recovery of four fractions, which were evaluated simultaneously in both in vitro and in vivo systems against B. malayi. The chloroform fraction at 250 mg/kg orally for 5 days exhibited the highest macrofilaricidal action (42.5%), closely followed by the insoluble n-butanol fraction (34.3%), the soluble hexane fraction (32.4%), and the soluble n-butanol fraction (20.4%). In addition, the hexane soluble fraction caused 44.3% sterilization of the surviving female parasites. Two compounds isolated were found devoid of antifilarial activity. PMID:15258853

Lakshmi, V; Saxena, A; Pandey, K; Bajpai, Preeti; Misra-Bhattacharya, Shailja

2004-07-01

129

Molecular phylogeny of echiuran worms (Phylum: Annelida) reveals evolutionary pattern of feeding mode and sexual dimorphism.  

PubMed

The Echiura, or spoon worms, are a group of marine worms, most of which live in burrows in soft sediments. This annelid-like animal group was once considered as a separate phylum because of the absence of segmentation, although recent molecular analyses have placed it within the annelids. In this study, we elucidate the interfamily relationships of echiuran worms and their evolutionary pattern of feeding mode and sexual dimorphism, by performing molecular phylogenetic analyses using four genes (18S, 28S, H3, and COI) of representatives of all extant echiuran families. Our results suggest that Echiura is monophyletic and comprises two unexpected groups: [Echiuridae+Urechidae+Thalassematidae] and [Bonelliidae+Ikedidae]. This grouping agrees with the presence/absence of marked sexual dimorphism involving dwarf males and the paired/non-paired configuration of the gonoducts (genital sacs). Furthermore, the data supports the sister group relationship of Echiuridae and Urechidae. These two families share the character of having anal chaetae rings around the posterior trunk as a synapomorphy. The analyses also suggest that deposit feeding is a basal feeding mode in echiurans and that filter feeding originated once in the common ancestor of Urechidae. Overall, our results contradict the currently accepted order-level classification, especially in that Echiuroinea is polyphyletic, and provide novel insights into the evolution of echiuran worms. PMID:23457618

Goto, Ryutaro; Okamoto, Tomoko; Ishikawa, Hiroshi; Hamamura, Yoichi; Kato, Makoto

2013-01-01

130

Phylogenetic reference data for systematics and phylotaxonomy of arbuscular mycorrhizal fungi from phylum to species level.  

PubMed

Although the molecular phylogeny, evolution and biodiversity of arbuscular mycorrhizal fungi (AMF) are becoming clearer, phylotaxonomically reliable sequence data are still limited. To fill this gap, a data set allowing resolution and environmental tracing across all taxonomic levels is provided. Two overlapping nuclear DNA regions, totalling c. 3 kb, were analysed: the small subunit (SSU) rRNA gene (up to 1800 bp) and a fragment spanning c. 250 bp of the SSU rDNA, the internal transcribed spacer (ITS) region (c. 475-520 bp) and c. 800 bp of the large subunit (LSU) rRNA gene. Both DNA regions together could be analysed for 35 described species, the SSU rDNA for c. 76 named and 18 as yet undefined species, and the ITS region or LSU rDNA, or a combination of both, for c. 91 named and 16 as yet undefined species. Present phylogenetic analyses, based on the three rDNA markers, provide reliable and robust resolution from phylum to species level. Altogether, 109 named species and 27 cultures representing as yet undefined species were analysed. This study provides a reference data set for molecular systematics and environmental community analyses of AMF, including analyses based on deep sequencing. PMID:22150759

Krüger, Manuela; Krüger, Claudia; Walker, Christopher; Stockinger, Herbert; Schüssler, Arthur

2012-03-01

131

Global Patterns of Abundance, Diversity and Community Structure of the Aminicenantes (Candidate Phylum OP8)  

PubMed Central

We investigated the global patterns of abundance, diversity, and community structure of members of the Aminicenantes (candidate phylum OP8). Our aim was to identify the putative ecological role(s) played by members of this poorly characterized bacterial lineages in various ecosystems. Analysis of near full-length 16S rRNA genes identified four classes and eight orders within the Aminicenantes. Within 3,134 datasets comprising ?1.8 billion high throughput-generated partial 16S rRNA genes, 47,351 Aminicenantes-affiliated sequences were identified in 913 datasets. The Aminicenantes exhibited the highest relative abundance in hydrocarbon-impacted environments, followed by marine habitats (especially hydrothermal vents and coral-associated microbiome samples), and aquatic, non-marine habitats (especially in terrestrial springs and groundwater samples). While the overall abundance of the Aminicenantes was higher in low oxygen tension as well as non-saline and low salinity habitats, it was encountered in a wide range of oxygen tension, salinities, and temperatures. Analysis of the community structure of the Aminicenantes showed distinct patterns across various datasets that appear to be, mostly, driven by habitat variations rather than prevalent environmental parameters. We argue that the detection of the Aminicenantes across environmental extremes and the observed distinct community structure patterns reflect a high level of intraphylum metabolic diversity and adaptive capabilities that enable its survival and growth in a wide range of habitats and environmental conditions.

Farag, Ibrahim F.; Davis, James P.; Youssef, Noha H.; Elshahed, Mostafa S.

2014-01-01

132

A Review of Recent Patents on the Protozoan Parasite HSP90 as a Drug Target  

PubMed Central

Diseases caused by protozoan parasites are still an important health problem. These parasites can cause a wide spectrum of diseases, some of which are severe and have high morbidity or mortality if untreated. Since they are still uncontrolled, it is important to find novel drug targets and develop new therapies to decrease their remarkable social and economic impact on human societies. In the past years, human HSP90 has become an interesting drug target that has led to a large number of investigations both at state organizations and pharmaceutical companies, followed by clinical trials. The finding that HSP90 has important biological roles in some protozoan parasites like Plasmodium spp, Toxoplasma gondii and trypanosomatids has allowed the expansion of the results obtained in human cancer to these infections. This review summarizes the latest important findings showing protozoan HSP90 as a drug target and presents three patents targeting T. gondii, P. falciparum and trypanosomatids HSP90.

Angel, Sergio O; Matrajt, Mariana; Echeverria, Pablo C

2013-01-01

133

Prevalence of intestinal protozoan infections among Orang Asli schoolchildren in Pos Senderut, Pahang, Malaysia.  

PubMed

The current study determined the prevalence of intestinal protozoan infections among the Orang Asli schoolchildren in Pos Senderut, Pahang, Malaysia. The overall intestinal protozoan infection rate was 85% (261 out of 307). The highest prevalence rates were due to Entamoeba coli (24.4%), Giardia lamblia (21.8%), Blastocystis hominis (21.2%) and Entamoeba histolytica (15.0%). The prevalence of Iodamoeba butschlii was only 2.9%. Among the positive samples, mixed infection with B. hominis and E. histolytica was 3.3%, B. hominis and G. lamblia was 2.9%, G. lamblia and E. histolytica was 2.0% and triple infections (B. hominis, G. lamblia and E. histolytica) was 1.0 %. The prevalence of the infection was high in all age groups (6-14 years old). Thus, we can conclude that intestinal protozoan infections are still representing a serious public health problem in aboriginal communities, especially among children. PMID:24640856

Al-Harazi, Talal; Ghani, Mohamed Kamel Abd; Othman, Hidayatulfathi

2013-12-01

134

A Population Survey of Members of the Phylum Bacteroidetes Isolated from Salt Marsh Sediments along the East Coast of the United States  

Microsoft Academic Search

The population diversity of cultured isolates of the phylum Bacteroidetes was investigated from salt-marsh sediments. A total of 44 isolates that belonged to this phylum were isolated either from high-dilution plates or from end-dilution most-probable-number (MPN) tubes. The majority of the isolates came from Virginia, with others isolated from salt marshes in Delaware and North Carolina. All the isolates were

C. Lydell; L. Dowell; M. Sikaroodi; P. Gillevet; D. Emerson

2004-01-01

135

Spring distribution of larger (>64 ?m) protozoans in the Atlantic sector of the Southern Ocean  

NASA Astrophysics Data System (ADS)

Distribution of larger protozoans (armoured dinoflagellates, tintinnids, heliozoans, radiolarians and foraminiferans >64 ?m) is presented for three major water masses of the Southern Ocean: the Polar Front region (PFr), the southern Antarctic Circumpolar Current (southern ACC) and the northern Weddell Gyre. Sampling took place during the SO-JGOFS cruise ANT X/6 of R/V Polarstern (October-November 1992) along a meridional transect at 6°W between 48°00'S and 59°30'S. Multinet samples (64 ?m mesh size) were taken at six stations from the surface down to 500 m depth at five different depth intervals. In the upper 100 m of the water column abundances of larger protozoans varied between 94 and 10,930 ind. m -3, with highest abundances in the PFr, where phytoplankton blooms occurred, and lowest values in the Antarctic Circumpolar Current-Weddell Gyre Boundary (AWB). Foraminiferans and polycystine and smaller (<300 ?m) phaeodarian radiolarians dominated larger protozoan assemblages in the PFr. In open water of the southern ACC, tintinnids, armoured dinoflagellates, foraminiferans and smaller (<300 ?m) phaeodarian radiolarians were equally important. The heliozoans Sticholonche spp. and nassellarian radiolarians dominated assemblages in the Weddell Gyre and AWB. Larger protozoan biomasses ranged between 2 and 674 ?g C m -3 and were always dominated by larger (>300 ?m) phaeodarians. Highest biomasses were found in the AWB between 200 and 500 m depth. Standing stocks of larger protozoans constituted a negligible fraction of zooplankton biomass in the upper 200 m of the water column. In deeper layers of the ice-covered Weddell Gyre and AWB their biomasses, dominated by larger (>300 ?m) phaeodarians, was significant contributing up to 45% to total larger protozoan and metazoan biomass. Analysis of correlation between distribution patterns and environmental conditions at the stations sampled indicate that spring distribution patterns of heterotrophic armoured dinoflagellates, polycystine radiolarians and foraminiferans follow productivity in the water column. Of the protozoan groups studied the smaller (<300 ?m) phaeodarian radiolarians also showed a significant correlation with productivity during spring, however, results from previous studies do not suggest a consistent pattern. Spring distribution patterns of other larger protozoans were not related to differences in productivity in the water column, and effects such as ice-cover, grazing or silica limitation might be determining. Dead radiolarian skeletons constituted on average 27, 8 and 11% of the population of nassellarians, spumellarians and smaller (<300 ?m) phaeodarians, respectively. The contribution of dead radiolarian skeletons to total radiolarian stocks varied with depth and water mass. Differences between live and skeleton assemblages composition were observed. These differences should be taken into consideration when interpreting the geological record.

Klaas, Christine

2001-07-01

136

Description of a riboflavin biosynthetic gene variant prevalent in the phylum Proteobacteria.  

PubMed

Riboflavin (vitamin B2) is the precursor of flavin mononucleotide and flavin adenine dinucleotide, which are cofactors essential for a host of intracellular redox reactions. Microorganisms synthesize flavins de novo to fulfill nutritional requirements, but it is becoming increasingly clear that flavins play a wider role in cellular physiology than was previously appreciated. Flavins mediate diverse processes beyond the cytoplasmic membrane, including iron acquisition, extracellular respiration, and interspecies interactions. While investigating the regulation of flavin electron shuttle biosynthesis in the Gram-negative gammaproteobacterium Shewanella oneidensis, we discovered that a riboflavin biosynthetic gene (ribBA) annotated as encoding a bifunctional 3,4-dihydroxy-2-butanone 4-phosphate (DHBP) synthase/GTP cyclohydrolase II does not possess both functions. The novel gene, renamed ribBX here, encodes an amino-terminal DHBP synthase domain. The carboxy-terminal end of RibBX not only lacks GTP cyclohydrolase II activity but also has evolved a different function altogether in S. oneidensis, regulating the activity of the DHBP synthase domain. Phylogenetic analysis revealed that the misannotation of ribBX as ribBA is rampant throughout the phylum Proteobacteria (40% of 2,173 annotated ribBA genes) and that ribBX emerged early in the evolution of this group of microorganisms. We examined the functionality of representative ribBX genes from Beta-, Gamma-, and Epsilonproteobacteria and found that, consistent with sequence-based predictions, the encoded GTP cyclohydrolase II domains lack catalytic activity. The persistence of ribBX in the genomes of so many phylogenetically divergent bacterial species lends weight to the argument that ribBX has evolved a function which lends a selective advantage to the host. PMID:24097946

Brutinel, Evan D; Dean, Antony M; Gralnick, Jeffrey A

2013-12-01

137

Nitrification expanded: discovery, physiology and genomics of a nitrite-oxidizing bacterium from the phylum Chloroflexi  

PubMed Central

Nitrite-oxidizing bacteria (NOB) catalyze the second step of nitrification, a major process of the biogeochemical nitrogen cycle, but the recognized diversity of this guild is surprisingly low and only two bacterial phyla contain known NOB. Here, we report on the discovery of a chemolithoautotrophic nitrite oxidizer that belongs to the widespread phylum Chloroflexi not previously known to contain any nitrifying organism. This organism, named Nitrolancetus hollandicus, was isolated from a nitrifying reactor. Its tolerance to a broad temperature range (25–63?°C) and low affinity for nitrite (Ks=1?m?), a complex layered cell envelope that stains Gram positive, and uncommon membrane lipids composed of 1,2-diols distinguish N. hollandicus from all other known nitrite oxidizers. N. hollandicus grows on nitrite and CO2, and is able to use formate as a source of energy and carbon. Genome sequencing and analysis of N. hollandicus revealed the presence of all genes required for CO2 fixation by the Calvin cycle and a nitrite oxidoreductase (NXR) similar to the NXR forms of the proteobacterial nitrite oxidizers, Nitrobacter and Nitrococcus. Comparative genomic analysis of the nxr loci unexpectedly indicated functionally important lateral gene transfer events between Nitrolancetus and other NOB carrying a cytoplasmic NXR, suggesting that horizontal transfer of the NXR module was a major driver for the spread of the capability to gain energy from nitrite oxidation during bacterial evolution. The surprising discovery of N. hollandicus significantly extends the known diversity of nitrifying organisms and likely will have implications for future research on nitrification in natural and engineered ecosystems.

Sorokin, Dimitry Y; Lucker, Sebastian; Vejmelkova, Dana; Kostrikina, Nadezhda A; Kleerebezem, Robbert; Rijpstra, W Irene C; Damste, Jaap S Sinninghe; Le Paslier, Denis; Muyzer, Gerard; Wagner, Michael; van Loosdrecht, Mark C M; Daims, Holger

2012-01-01

138

Complete genome of Candidatus Chloracidobacterium thermophilum, a chlorophyll-based photoheterotroph belonging to the phylum Acidobacteria.  

PubMed

Candidatus Chloracidobacterium thermophilum, which naturally inhabits microbial mats of alkaline siliceous hot springs in Yellowstone National Park, is the only known chlorophototroph in the phylum Acidobacteria. The Ca. C. thermophilum genome was composed of two chromosomes (2,683,362 bp and 1,012,010 bp), and both encoded essential genes. The genome included genes to produce chlorosomes, the Fenna-Matthews-Olson protein, bacteriochlorophylls a and c as principal pigments, and type-1, homodimeric reaction centres. Ca. C. thermophilum is an aerobic photoheterotroph that lacks the ability to synthesize several essential nutrients. Key genes of all known carbon fixation pathways were absent, as were genes for assimilatory nitrate and sulfate reduction and vitamin B(12) synthesis. Genes for the synthesis of branched-chain amino acids (valine, isoleucine and leucine) were also absent, but genes for catabolism of these compounds were present. This observation suggested that Ca. C. thermophilum may synthesize branched-chain amino acids from an intermediate(s) of the catabolic pathway by reversing these reactions. The genome encoded an aerobic respiratory electron transport chain that included NADH dehydrogenase, alternative complex III and cytochrome oxidase. The chromosomes of the laboratory isolate were compared with assembled, metagenomic scaffolds from the major Ca. C. thermophilum population in hot-spring mats. The larger chromosomes of the two populations were highly syntenous but significantly divergent (~13%) in sequence. In contrast, the smaller chromosomes have undergone numerous rearrangements, contained many transposases, and might be less constrained by purifying selection than the large chromosomes. Some transposases were homologous to those of mat community members from other phyla. PMID:21951563

Garcia Costas, Amaya M; Liu, Zhenfeng; Tomsho, Lynn P; Schuster, Stephan C; Ward, David M; Bryant, Donald A

2012-01-01

139

Siphonobacter aquaeclarae gen. nov., sp. nov., a novel member of the family 'Flexibacteraceae', phylum Bacteroidetes.  

PubMed

A Gram-negative bacterium, designated P2(T), was isolated from the biofilm developed on the inner surface of an ultrapure cooling water system in a Hungarian power plant and was characterized by a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain P2(T) was affiliated with the family 'Flexibacteraceae' in the phylum Bacteroidetes. Its closest relative was Flectobacillus lacus CL-GP79(T) (88.7?% 16S rRNA gene sequence similarity) followed by Arcicella rosea TW5(T) (86.5?%), Arcicella aquatica NO-502(T) (86.4?%), Flectobacillus roseus GFA-11(T) (86.3?%) and Flectobacillus major DSM 103(T) (85.4?%). Cells of strain P2(T) were facultatively anaerobic, non-motile rods. The major fatty acids were C(16?:?1)?5c (42.5?%), iso-C(15?:?0) 2-OH (17.2?%), iso-C(17?:?0) 3-OH (16.1?%) and iso-C(15?:?0) (8.5?%). The major menaquinone was MK-7 and the predominant polar lipid was phosphatidylethanolamine. The DNA G+C content was 54.5 mol%. Thus, the phenotypic and genotypic analyses clearly showed that strain P2(T) is considerably different from members of other genera in the family 'Flexibacteraceae'. Based on these results, it is concluded that strain P2(T) represents a novel species in a new genus, for which the name Siphonobacter aquaeclarae gen. nov., sp. nov. is proposed, with type strain P2(T) (=DSM 21668(T) =NCAIM B 02328(T)). PMID:20008110

Táncsics, András; Kéki, Zsuzsa; Márialigeti, Károly; Schumann, Peter; Tóth, Erika M

2010-11-01

140

Besnoitia neotomofelis n. sp. (Protozoa: Apicomplexa) from the southern plains woodrat ( Neotoma micropus).  

PubMed

Certain species of the protozoan genus Besnoitia cause clinical disease in livestock and wildlife. In the present paper a new species, Besnoitia neotomofelis is described from the southern planes woodrat (Neotoma micropus). The parasite was detected by bioassay of woodrat tissues in outbred Swiss Webster mice in an attempt to isolate Toxoplasma gondii. Initially, the organism was misdiagnosed as T. gondii because it was highly pathogenic for mice and its tachyzoites resembled T. gondii tachyzoites. Further studies revealed that it differed structurally and biologically from T. gondii. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells, and in vivo in mice. Non-dividing, uninucleate tachyzoites were approximately 1 x 5 ?m in size. Longitudinally-cut bradyzoites in tissue sections measured 1.5-1.6 x 7.7-9.3 ?m. Tissue cysts were microscopic, up to 210 ?m long, and were infective orally to mice. Cats fed tissue cysts shed unsporulated 13 x 14 ?m sized oocysts. All mice inoculated with B. neotomofelis died of acute besnoitiosis, irrespective of the dose, and Norwegian rats became infected but remained asymptomatic. Entero-epithelial stages (schizonts, gamonts) were found in cats fed tissue cysts. Large (up to 40 x 50 ?m) first-generation schizonts developed in the lamina propria of the small intestine of cats. A second generation of small sized (8 ?m) schizonts containing 4-8 merozoites was detected in enterocytes of the small intestine. Gamonts and oocysts were seen in goblet cells of the small intestinal epithelium. Tachyzoites were present in mesenteric lymph nodes of cats. Phylogenetic analysis indicated that B. neotomofelis was related to other Besnoitia species from rodents, rabbits, and opossums. Besnoitia neotomofelis is distinct from the 3 other species of Besnoitia, B. wallacei, B. darlingi and B. oryctofelisi that utilize cats as a definitive host. PMID:20561393

Dubey, J P; Yabsley, M J

2010-10-01

141

Evidence of Intraflagellar Transport and Apical Complex Formation in a Free-Living Relative of the Apicomplexa  

PubMed Central

Since its first description, Chromera velia has attracted keen interest as the closest free-living relative of parasitic Apicomplexa. The life cycle of this unicellular alga is complex and involves a motile biflagellate form. Flagella are thought to be formed in the cytoplasm, a rare phenomenon shared with Plasmodium in which the canonical mode of flagellar assembly, intraflagellar transport, is dispensed with. Here we demonstrate the expression of intraflagellar transport components in C. velia, answering the question of whether this organism has the potential to assemble flagella via the canonical route. We have developed and characterized a culturing protocol that favors the generation of flagellate forms. From this, we have determined a marked shift in the mode of daughter cell production from two to four daughter cells per division as a function of time after passage. We conduct an ultrastructural examination of the C. velia flagellate form by using serial TEM and show that flagellar biogenesis in C. velia occurs prior to cytokinesis. We demonstrate a close association of the flagellar apparatus with a complex system of apical structures, including a micropore, a conoid, and a complex endomembrane system reminiscent of the apical complex of parasitic apicomplexans. Recent work has begun to elucidate the possible flagellar origins of the apical complex, and we show that in C. velia these structures are contemporaneous within a single cell and share multiple connections. We propose that C. velia therefore represents a vital piece in the puzzle of the origins of the apical complex.

Portman, Neil; Foster, Christie; Walker, Giselle

2014-01-01

142

Mitochondrial translation in absence of local tRNA aminoacylation and methionyl tRNA Met formylation in Apicomplexa.  

PubMed

Apicomplexans possess three translationally active compartments: the cytosol, a single tubular mitochondrion, and a vestigial plastid organelle called apicoplast. Mitochondrion and apicoplast are of bacterial evolutionary origin and therefore depend on a bacterial-like translation machinery. The minimal mitochondrial genome contains only three ORFs, and in Toxoplasma gondii the absence of mitochondrial tRNA genes is compensated for by the import of cytosolic eukaryotic tRNAs. Although all compartments require a complete set of charged tRNAs, the apicomplexan nuclear genomes do not hold sufficient aminoacyl-tRNA synthetase (aaRSs) genes to be targeted individually to each compartment. This study reveals that aaRSs are either cytosolic, apicoplastic or shared between the two compartments by dual targeting but are absent from the mitochondrion. Consequently, tRNAs are very likely imported in their aminoacylated form. Furthermore, the unexpected absence of tRNA(Met) formyltransferase and peptide deformylase implies that the requirement for a specialized formylmethionyl-tRNA(Met) for translation initiation is bypassed in the mitochondrion of Apicomplexa. PMID:20374492

Pino, Paco; Aeby, Eric; Foth, Bernardo Javier; Sheiner, Lilach; Soldati, Thierry; Schneider, Andre; Soldati-Favre, Dominique

2010-05-01

143

Improvements in transfection efficiency and tests of RNA interference (RNAi) approaches in the protozoan parasite Leishmania  

Microsoft Academic Search

Approaches which eliminate mRNA expression directly are ideally suited for reverse genetics applications in eukaryotic microbes which are asexual diploids, such as the protozoan parasite Leishmania. RNA interference (RNAi) approaches have been successful in many species, including the related parasite Trypanosoma brucei. For RNAi tests in Leishmania, we developed improved protocols for transient and stable DNA transfection, attaining efficiencies of

Kelly A. Robinson; Stephen M. Beverley

2003-01-01

144

ANTIOXIDANT ENZYMES, POTENTIAL VIRULENT FACTORS, IN DIFFERENT STRAINS OF THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS  

EPA Science Inventory

The oyster protozoan parasite, Perkinsus marinus, is one of the two important parasites causing severe mortality in the eastern oysters (Crassostrea virginica) on the US east coast. Our recent study suggests that P. marinus cells and its extracellular products (ECP) could scaveng...

145

Soil respiration profiles and protozoan enumeration agree as microbial growth indicators  

Microsoft Academic Search

Carbon, nitrogen or phosphorus limitation of microbial growth in a forest and a field soil was evaluated from measurements of respiration and protozoan counts after nutrient addition. In both soils simultaneous addition of C (glucose) and N (NH4NO3) resulted in microbial growth as indicated by a gradual increase in respiration rate whereas a single addition of C did not induce

S. Christensen; R. Rønn; F. Ekelund; B. Andersen; J. Damgaard; U. Friberg-Jensen; L. Jensen; H. Kill; B. Larsen; J. Larsen; C. Riis; K. Thingsgaard; C. Thirup; A. Tom-Petersen; L. Vesterdal

1996-01-01

146

Metronidazole induces programmed cell death in the protozoan parasite Blastocystis hominis  

Microsoft Academic Search

Previous studies by the authors have shown that the protozoan parasite Blastocystis hominis succumbed to a cytotoxic monoclonal antibody with a number of cellular and biochemical features characteristic of apoptosis in higher eukaryotes. The present study reports that apoptosis-like features are also observed in growing cultures of axenic B. hominis upon exposure to metronidazole, a drug commonly used for the

A. M. A. Nasirudeen; Yap Eu Hian; Mulkit Singh; Kevin S. W. Tan

2004-01-01

147

Persistence of Free-Living Protozoan Communities across Rearing Cycles in Commercial Poultry Houses ?  

PubMed Central

The introduction and survival of zoonotic bacterial pathogens in poultry farming have been linked to bacterial association with free-living protozoa. To date, however, no information is available on the persistence of protozoan communities in these environments across consecutive rearing cycles and how it is affected by farm- and habitat-specific characteristics and management strategies. We therefore investigated the spatial and temporal dynamics of free-living protozoa in three habitats (pipeline, water, and miscellaneous samples) in three commercial poultry houses across three rearing cycles by using the molecular fingerprinting technique denaturing gradient gel electrophoresis (DGGE). Our study provides strong evidence for the long-term (ca. 6-month) persistence of protozoa in broiler houses across consecutive rearing cycles. Various free-living protozoa (flagellates, ciliates, and amoebae), including known vectors of bacterial pathogens, were observed during the down periods in between rearing cycles. In addition, multivariate analysis and variation partitioning showed that the protozoan community structure in the broiler houses showed almost no change across rearing cycles and remained highly habitat and farm specific. Unlike in natural environments, protozoan communities inside broiler houses are therefore not seasonal. Our results imply that currently used biosecurity measures (cleaning and disinfection) applied during the down periods are not effective against many protozoans and therefore cannot prevent potential cross-contamination of bacterial pathogens via free-living protozoa between rearing cycles.

Bare, Julie; Houf, Kurt; Verstraete, Tine; Vaerewijck, Mario; Sabbe, Koen

2011-01-01

148

Experimental studies of protozoan response to intense magnetic fields and forces  

Microsoft Academic Search

Intense static magnetic fields of up to 31 Tesla were used as a novel tool to manipulate the swimming mechanics of unicellular organisms. It is shown that homogenous magnetic fields alter the swimming trajectories of the single cell protozoan Paramecium caudatum, by aligning them parallel to the applied field. Immobile neutrally buoyant paramecia also oriented in magnetic fields with similar

Karine Guevorkian

2006-01-01

149

Movement of the protozoan pathogen Cryptosporidium parvum through three contrasting soil types  

Microsoft Academic Search

The potential for transfer of the protozoan pathogen Cryptosporidium parvum through soil to land drains and, subsequently, water courses following the application of livestock waste to land was monitored in the laboratory using simulated rainfall and intact soil cores. Following irrigation over a 21-day period, Cryptosporidium parvum oocysts applied to the surface of soil cores (initial inoculum concentration 1×108 oocysts

Jane L. Mawdsley; Alison E. Brooks; Roger J. Merry

1996-01-01

150

Biomonitoring of coastal pollution status using protozoan communities with a modified PFU method  

Microsoft Academic Search

Structural and functional parameters of protozoan communities were assessed as indicators of water quality in Korean coastal waters in the summer of 2000. A modified polyurethane foam unit (PFU) method, named the bottled PFU (BPFU) system, was used in order to carry out the bioassessment. Both parameters suggested that biomonitoring using the BPFU system was more effective than the conventional

Kuidong Xu; Joong Ki Choi; Eun Jin Yang; Kyu Chul Lee; Yanli Lei

2002-01-01

151

[Formation and diversity of parasitophorous vacuoles in parasitic protozoa. The Coccidia (Sporozoa, Apicomplexa)].  

PubMed

Data on parasitophorous vacuole (PV) formation in host cells (HC) harbouring different intracellular protozoan parasites have been reviewed and critically analysed, with special reference to the main representatives of the Coccidia. The vacuole membrane (PVM) is the interface between host and parasite, playing a role in nutrient acquisition by the parasite from the HC. The PV phenomenon is regarded as a generalized HC response to the introduction of alien bodies (microorganisms), which eventually reflects the evolutionary established host-parasite relationships at cellular, subcellular and molecular levels. Special attention has been paid to the existing morpho-functional diversity of the PVs within the same genera and species of parasites, and even at different stages of the parasite life cycle. The PVM is generally considered to derive from the HC plasmalemma, whose biochemical composition undergoes significant changes as the intravacuolar parasite grows. The original HC proteins are selectively excluded from the PVM, while those of the parasite are incorporated. As the result, the changed PVM becomes not fusigenic for HC lysosomes. For Toxoplasma gondii and other cyst-forming coccidia (Isospora, Sarcocystis), a definite correlation has been noticed between the extent of rhoptry and dense granule secrets released by a zoite during HC internalization, on the one hand, and the pattern of the PV that forms, on the other one. In T. gondii, tachyzoites, known to discharge abundant secrets, commonly force the development of PVs limited with a single unit membrane and equipped with a tubulovesicular network in the lumen. Unlike, bradyzoites known to be deficient in secretory materials trigger the formation of PVs with a three-membrane lining composed of the changed invaginated plasmalemma in addition to two membranes of endoplasmic reticulum. The two different types of PV harbour, respectively, exoenteric and enteric stages of T. gondii, the latter being confined to the cat intestine only. Unlike, all endogenous stages of the classic intestinal coccidia (Eimeria spp.) develop within PVs limited with a single membrane, with some invaginations extending into the PV lumen. Unusual PV patterns are characteristic of the extracytoplasmic eimerian coccidia (Cryptosporidium, Epieimeria) and adeleid haemogreagarines (Karyolysus). In cyst-forming coccidia, the PVM is actively involved in tissue cyst wall formation, thus protecting the encysted parasites from recognition by the host immune system. All this strongly suggests that the PV is far from being an indifferent membraneous vesicle containing a parasite, but represents a metabolically active compartment in infected cells. Since all the coccidia are obligate intracellular parasites, the mode of their intimate interaction with the HC, largely accomplished via the PV and its membrane, is vital for their survival as biological species. PMID:14520865

Be?er, T V; Svezhova, N V; Radchenko, A I; Sidorenko, N V

2003-01-01

152

Real-time PCR detection of bacteria belonging to the Firmicutes Phylum.  

PubMed

Members of the bacterial Phylum Firmicutes occupy a wide range of habitats and can be either beneficial or detrimental in diverse settings, including food- and beverage-related industries. Firmicutes are responsible for the vast majority of beer-spoilage incidents and, as such, they have a substantial financial impact in the brewing industry. Rapid detection and identification of a bacterium as a Firmicutes is difficult due to widespread genetic transfer and genome reduction resulting in phenotypic diversity in these bacteria. Here we describe a real-time multiplex PCR to detect and differentiate Firmicutes associated with beer-spoilage from non-Firmicutes bacteria that may be present as benign environmental contaminants. A region of the 16S rRNA gene was identified and predicted to be highly conserved amongst, and essentially specific for, Firmicutes. A real-time PCR assay using a hydrolysis probe targeting this region of the 16S rRNA gene was experimentally shown to detect ten genera of Firmicutes known to be beer spoilers, but does not cross-react with eleven of twelve non-Firmicutes genera which can periodically appear in beer. Only one non-Firmicutes species, Zymomonas mobilis, weakly reacted with the Firmicutes probe. This rPCR assay has a standard curve that is linear over six orders of magnitude of DNA, with a quantitation limit of DNA from <10 bacteria. When used to detect bacteria present in beer, the assay was able to detect 50-100 colony forming units (CFU) of Firmicutes directly from 2.5 cm membranes used to filter 100 ml of contaminated beer. Through incorporation of a 4.7 cm filter and an overnight pre-enrichment incubation, the sensitivity was increased to 2.5-10 CFU per package of beer (341 ml). When multiplexed with a second hydrolysis probe targeting a universal region of the 16S rRNA gene, the assay reliably differentiates between Firmicutes and non-Firmicutes bacteria found in breweries. PMID:18501458

Haakensen, M; Dobson, C M; Deneer, H; Ziola, B

2008-07-31

153

Mannosylglucosylglycerate biosynthesis in the deep-branching phylum Planctomycetes: characterization of the uncommon enzymes from Rhodopirellula baltica  

PubMed Central

The biosynthetic pathway for the rare compatible solute mannosylglucosylglycerate (MGG) accumulated by Rhodopirellula baltica, a marine member of the phylum Planctomycetes, has been elucidated. Like one of the pathways used in the thermophilic bacterium Petrotoga mobilis, it has genes coding for glucosyl-3-phosphoglycerate synthase (GpgS) and mannosylglucosyl-3-phosphoglycerate (MGPG) synthase (MggA). However, unlike Ptg. mobilis, the mesophilic R. baltica uses a novel and very specific MGPG phosphatase (MggB). It also lacks a key enzyme of the alternative pathway in Ptg. mobilis – the mannosylglucosylglycerate synthase (MggS) that catalyses the condensation of glucosylglycerate with GDP-mannose to produce MGG. The R. baltica enzymes GpgS, MggA, and MggB were expressed in E. coli and characterized in terms of kinetic parameters, substrate specificity, temperature and pH dependence. This is the first characterization of genes and enzymes for the synthesis of compatible solutes in the phylum Planctomycetes and for the synthesis of MGG in a mesophile.

Cunha, Sofia; d'Avo, Ana Filipa; Mingote, Ana; Lamosa, Pedro; da Costa, Milton S.; Costa, Joana

2013-01-01

154

Conservation of proteobacterial magnetosome genes and structures in an uncultivated member of the deep-branching Nitrospira phylum.  

PubMed

Magnetotactic bacteria (MTB) are a phylogenetically diverse group which uses intracellular membrane-enclosed magnetite crystals called magnetosomes for navigation in their aquatic habitats. Although synthesis of these prokaryotic organelles is of broad interdisciplinary interest, its genetic analysis has been restricted to a few closely related members of the Proteobacteria, in which essential functions required for magnetosome formation are encoded within a large genomic magnetosome island. However, because of the lack of cultivated representatives from other phyla, it is unknown whether the evolutionary origin of magnetotaxis is monophyletic, and it has been questioned whether homologous mechanisms and structures are present in unrelated MTB. Here, we present the analysis of the uncultivated "Candidatus Magnetobacterium bavaricum" from the deep branching Nitrospira phylum by combining micromanipulation and whole genome amplification (WGA) with metagenomics. Target-specific sequences obtained by WGA of cells, which were magnetically collected and individually sorted from sediment samples, were used for PCR screening of metagenomic libraries. This led to the identification of a genomic cluster containing several putative magnetosome genes with homology to those in Proteobacteria. A variety of advanced electron microscopic imaging tools revealed a complex cell envelope and an intricate magnetosome architecture. The presence of magnetosome membranes as well as cytoskeletal magnetosome filaments suggests a similar mechanism of magnetosome formation in "Cand. M. bavaricum" as in Proteobacteria. Altogether, our findings suggest a monophyletic origin of magnetotaxis, and relevant genes were likely transferred horizontally between Proteobacteria and representatives of the Nitrospira phylum. PMID:21191098

Jogler, Christian; Wanner, Gerhard; Kolinko, Sebastian; Niebler, Martina; Amann, Rudolf; Petersen, Nikolai; Kube, Michael; Reinhardt, Richard; Schüler, Dirk

2011-01-18

155

Conservation of proteobacterial magnetosome genes and structures in an uncultivated member of the deep-branching Nitrospira phylum  

PubMed Central

Magnetotactic bacteria (MTB) are a phylogenetically diverse group which uses intracellular membrane-enclosed magnetite crystals called magnetosomes for navigation in their aquatic habitats. Although synthesis of these prokaryotic organelles is of broad interdisciplinary interest, its genetic analysis has been restricted to a few closely related members of the Proteobacteria, in which essential functions required for magnetosome formation are encoded within a large genomic magnetosome island. However, because of the lack of cultivated representatives from other phyla, it is unknown whether the evolutionary origin of magnetotaxis is monophyletic, and it has been questioned whether homologous mechanisms and structures are present in unrelated MTB. Here, we present the analysis of the uncultivated “Candidatus Magnetobacterium bavaricum” from the deep branching Nitrospira phylum by combining micromanipulation and whole genome amplification (WGA) with metagenomics. Target-specific sequences obtained by WGA of cells, which were magnetically collected and individually sorted from sediment samples, were used for PCR screening of metagenomic libraries. This led to the identification of a genomic cluster containing several putative magnetosome genes with homology to those in Proteobacteria. A variety of advanced electron microscopic imaging tools revealed a complex cell envelope and an intricate magnetosome architecture. The presence of magnetosome membranes as well as cytoskeletal magnetosome filaments suggests a similar mechanism of magnetosome formation in “Cand. M. bavaricum” as in Proteobacteria. Altogether, our findings suggest a monophyletic origin of magnetotaxis, and relevant genes were likely transferred horizontally between Proteobacteria and representatives of the Nitrospira phylum.

Jogler, Christian; Wanner, Gerhard; Kolinko, Sebastian; Niebler, Martina; Amann, Rudolf; Petersen, Nikolai; Kube, Michael; Schuler, Dirk

2011-01-01

156

The Ultramicrobacterium "Elusimicrobium minutum" gen. nov., sp. nov., the First Cultivated Representative of the Termite Group 1 Phylum? †  

PubMed Central

Insect intestinal tracts harbor several novel, deep-rooting clades of as-yet-uncultivated bacteria whose biology is typically completely unknown. Here, we report the isolation of the first representative of the termite group 1 (TG1) phylum from sterile-filtered gut homogenates of a humivorous scarab beetle larva. Strain Pei191T is a mesophilic, obligately anaerobic ultramicrobacterium with a gram-negative cell envelope. Cells are typically rod shaped, but cultures are pleomorphic in all growth phases (0.3 to 2.5 ?m long and 0.17 to 0.3 ?m wide). The isolate grows heterotrophically on sugars and ferments d-galactose, d-glucose, d-fructose, d-glucosamine, and N-acetyl-d-glucosamine to acetate, ethanol, hydrogen, and alanine as major products but only if amino acids are present in the medium. PCR-based screening and comparative 16S rRNA gene sequence analysis revealed that strain Pei191T belongs to the “intestinal cluster,” a lineage of hitherto uncultivated bacteria present in arthropod and mammalian gut systems. It is only distantly related to the previously described so-called “endomicrobia” lineage, which comprises mainly uncultivated endosymbionts of termite gut flagellates. We propose the name “Elusimicrobium minutum” gen. nov., sp. nov. (type strain, Pei191T = ATCC BAA-1559T = JCM 14958T) for the first isolate of this deep-branching lineage and the name “Elusimicrobia” phyl. nov. for the former TG1 phylum.

Geissinger, Oliver; Herlemann, Daniel P. R.; Morschel, Erhard; Maier, Uwe G.; Brune, Andreas

2009-01-01

157

Symbiosis and insect diversification: an ancient symbiont of sap-feeding insects from the bacterial phylum Bacteroidetes.  

PubMed

Several insect groups have obligate, vertically transmitted bacterial symbionts that provision hosts with nutrients that are limiting in the diet. Some of these bacteria have been shown to descend from ancient infections. Here we show that the large group of related insects including cicadas, leafhoppers, treehoppers, spittlebugs, and planthoppers host a distinct clade of bacterial symbionts. This newly described symbiont lineage belongs to the phylum Bacteroidetes. Analyses of 16S rRNA genes indicate that the symbiont phylogeny is completely congruent with the phylogeny of insect hosts as currently known. These results support the ancient acquisition of a symbiont by a shared ancestor of these insects, dating the original infection to at least 260 million years ago. As visualized in a species of spittlebug (Cercopoidea) and in a species of sharpshooter (Cicadellinae), the symbionts have extraordinarily large cells with an elongate shape, often more than 30 mum in length; in situ hybridizations verify that these correspond to the phylum Bacteroidetes. "Candidatus Sulcia muelleri" is proposed as the name of the new symbiont. PMID:16332876

Moran, Nancy A; Tran, Phat; Gerardo, Nicole M

2005-12-01

158

Symbiosis and Insect Diversification: an Ancient Symbiont of Sap-Feeding Insects from the Bacterial Phylum Bacteroidetes  

PubMed Central

Several insect groups have obligate, vertically transmitted bacterial symbionts that provision hosts with nutrients that are limiting in the diet. Some of these bacteria have been shown to descend from ancient infections. Here we show that the large group of related insects including cicadas, leafhoppers, treehoppers, spittlebugs, and planthoppers host a distinct clade of bacterial symbionts. This newly described symbiont lineage belongs to the phylum Bacteroidetes. Analyses of 16S rRNA genes indicate that the symbiont phylogeny is completely congruent with the phylogeny of insect hosts as currently known. These results support the ancient acquisition of a symbiont by a shared ancestor of these insects, dating the original infection to at least 260 million years ago. As visualized in a species of spittlebug (Cercopoidea) and in a species of sharpshooter (Cicadellinae), the symbionts have extraordinarily large cells with an elongate shape, often more than 30 ?m in length; in situ hybridizations verify that these correspond to the phylum Bacteroidetes. “Candidatus Sulcia muelleri” is proposed as the name of the new symbiont.

Moran, Nancy A.; Tran, Phat; Gerardo, Nicole M.

2005-01-01

159

Protomagalhaensia richardsoni n. sp. (Apicomplexa: Eugregarinida: Blabericolidae): a new gregarine parasitizing the giant lobster cockroach, Henschoutedenia flexivitta (Dictyoptera: Blaberidae).  

PubMed

Protomagalhaensia richardsoni n. sp. (Apicomplexa: Eugregarinida: Blabericolidae) is described from the giant lobster cockroach, Henschoutedenia flexivitta (Dictyoptera: Blattaria: Blaberidae: Oxyhaloinae: Nauphoetini). Oocysts within the genus are dolioform with polar plates. Those of Protomagalhaensia granulosae, Protomagalhaensia wolfi, and Protomagalhaensia blaberae possess distinct apical spines and a sagittal depression that are absent or reduced in P. richardsoni and Protomagalhaensia cerastes. Oocysts of P. richardsoni are significantly longer with larger sporozoite-bearing cavities than those of P. blaberae, P. cerastes, P. granulosae, and P. wolfi (external oocyst length 8.07 ?m vs. 7.42 ?m, 7.50 ?m, 6.87 ?m, 7.56 ?m, respectively; internal oocyst length 6.94 ?m vs. 6.44 ?m, 6.77 ?m, 6.09 ?m, 6.72 ?m, respectively). All 5 species are also distinguished by unique oocyst length/width ratios. No unique morphological structure distinguishes among the gametocysts of Protomagalhaensia species, but gametocysts of P. richardsoni are significantly shorter than those of P. blaberae, P. cerastes, P. granulosae, and P. wolfi (gametocyst length 184.3 ?m vs. 325.15 ?m, 253.27 ?m, 273.63 ?m, 218.3 ?m, respectively). No structurally unique morphological gamont feature distinguishes among species of Protomagalhaensia. Rather, species distinctions are morphometric in nature. In general, gamonts of P. richardsoni are readily distinguished from those of P. cerastes and P. wolfi based on size alone: the latter species being roughly half the size of P. richardsoni. Gamonts of P. richardsoni are most similar to those of P. granulosae and P. blaberae but with relatively smaller primites and more slender satellites. PMID:23659501

Fauver, Joseph R; Clopton, Richard E; Clopton, Debra T

2013-10-01

160

Identification of a New Rhoptry Neck Complex RON9/RON10 in the Apicomplexa Parasite Toxoplasma gondii  

PubMed Central

Apicomplexan parasites secrete and inject into the host cell the content of specialized secretory organelles called rhoptries, which take part into critical processes such as host cell invasion and modulation of the host cell immune response. The rhoptries are structurally and functionally divided into two compartments. The apical duct contains rhoptry neck (RON) proteins that are conserved in Apicomplexa and are involved in formation of the moving junction (MJ) driving parasite invasion. The posterior bulb contains rhoptry proteins (ROPs) unique to an individual genus and, once injected in the host cell act as effector proteins to co-opt host processes and modulate parasite growth and virulence. We describe here two new RON proteins of Toxoplasma gondii, RON9 and RON10, which form a high molecular mass complex. In contrast to the other RONs described to date, this complex was not detected at the MJ during invasion and therefore was not associated to the MJ complex RON2/4/5/8. Disruptions of either RON9 or RON10 gene leads to the retention of the partner in the ER followed by subsequent degradation, suggesting that the RON9/RON10 complex formation is required for proper sorting to the rhoptries. Finally, we show that the absence of RON9/RON10 has no significant impact on the morphology of rhoptry, on the invasion and growth in fibroblasts in vitro or on virulence in vivo. The conservation of RON9 and RON10 in Coccidia and Cryptosporidia suggests a specific relation with development in intestinal epithelial cells.

Lamarque, Mauld H.; Papoin, Julien; Finizio, Anne-Laure; Lentini, Gaelle; Pfaff, Alexander W.; Candolfi, Ermanno; Dubremetz, Jean-Francois; Lebrun, Maryse

2012-01-01

161

Trichomonasvirus: a new genus of protozoan viruses in the family Totiviridae  

PubMed Central

The family Totiviridae includes a number of viruses with monosegmented dsRNA genomes and isometric virions that infect either fungi or a number of medically important protozoan parasites such as Leishmania and Giardia. A new genus, Trichomonasvirus, was recently proposed for this family. Its name is based on the genus of its host organism, Trichomonas vaginalis, a protozoan parasite that colonizes the human genitourinary mucosa and is the most common non-viral sexually transmitted infection in the world. The type species of this new genus is Trichomonas vaginalis virus 1. Distinguishing characteristics of the new genus include infection of a human sexually transmitted parasite, stable mixed infection with more than one distinct Trichomonasvirus species, and sequence-based phylogenetic divergence that distinguishes it from all other family members.

Goodman, Russell P.; Ghabrial, Said A.; Fichorova, Raina N.; Nibert, Max L.

2013-01-01

162

An unusually compact ribosomal DNA repeat in the protozoan Giardia lamblia.  

PubMed

The ribosomal RNA (rRNA) genes of the protozoan parasite Giardia lamblia have been analyzed with respect to size, composition and copy number. They are found to be remarkable in several respects. First, the rRNAs themselves are the smallest yet reported for any eukaryotic organism. Second, the genes encoding them are found as an exceptionally small tandemly repeated unit of only 5.4 kilobase-pairs. Third, the genes are extraordinarily G:C rich, even in regions which are highly conserved between all other eukaryotic rRNA genes. Finally, by analogy to other organisms, the 5.8S RNA appears to lack about 15 nucleotides from its 3'-end, a region previously thought to be essential for 5.8S RNA function. We also provide the first estimates of the genomic complexity and total G:C content of this important protozoan pathogen. PMID:3588284

Boothroyd, J C; Wang, A; Campbell, D A; Wang, C C

1987-05-26

163

DNA repair mechanisms in eukaryotes: Special focus in Entamoeba histolytica and related protozoan parasites.  

PubMed

Eukaryotic cell viability highly relies on genome stability and DNA integrity maintenance. The cellular response to DNA damage mainly consists of six biological conserved pathways known as homologous recombination repair (HRR), non-homologous end-joining (NHEJ), base excision repair (BER), mismatch repair (MMR), nucleotide excision repair (NER), and methyltransferase repair that operate in a concerted way to minimize genetic information loss due to a DNA lesion. Particularly, protozoan parasites survival depends on DNA repair mechanisms that constantly supervise chromosomes to correct damaged nucleotides generated by cytotoxic agents, host immune pressure or cellular processes. Here we reviewed the current knowledge about DNA repair mechanisms in the most relevant human protozoan pathogens. Additionally, we described the recent advances to understand DNA repair mechanisms in Entamoeba histolytica with special emphasis in the use of genomic approaches based on bioinformatic analysis of parasite genome sequence and microarrays technology. PMID:19591963

López-Camarillo, César; Lopez-Casamichana, Mavil; Weber, Christian; Guillen, Nancy; Orozco, Esther; Marchat, Laurence A

2009-12-01

164

Cellulase and Other Polymer-Hydrolyzing Activities of Trichomitopsis termopsidis, a Symbiotic Protozoan from Termites †  

PubMed Central

Crude extracts of the anaerobic, cellulolytic protozoan Trichomitopsis termopsidis possessed endo-?-1,4-glucanase and cellobiase activities, as evidenced by hydrolytic action on carboxymethyl cellulose and cellobiose, respectively. Cell extracts also hydrolyzed microcrystalline cellulose. Hydrolysis of microcrystalline cellulose displayed optima at pH 5 and at 30°C, and glucose was the sole product liberated. Cellulolytic activities of T. termopsidis appeared to be entirely cell associated. Hydrolytic activity was also detected against Douglas fir wood powder, xylan, starch, and protein, but not chitin. The importance of these enzymes in the nutrition of T. termopsidis is discussed in terms of the natural habitat of this protozoan (the hindgut of wood-eating termites).

Odelson, David A.; Breznak, John A.

1985-01-01

165

Impact of Protozoan Grazing on Bacterial Community Structure in Soil Microcosms  

PubMed Central

The influence of grazing by a mixed assemblage of soil protozoa (seven flagellates and one amoeba) on bacterial community structure was studied in soil microcosms amended with a particulate resource (sterile wheat roots) or a soluble resource (a solution of various organic compounds). Sterilized soil was reinoculated with mixed soil bacteria (obtained by filtering and dilution) or with bacteria and protozoa. Denaturing gradient gel electrophoresis (DGGE) of PCR amplifications of 16S rRNA gene fragments, as well as community level physiological profiling (Biolog plates), suggested that the mixed protozoan community had significant effects on the bacterial community structure. Excising and sequencing of bands from the DGGE gels indicated that high-G+C gram-positive bacteria closely related to Arthrobacter spp. were favored by grazing, whereas the excised bands that decreased in intensity were related to gram-negative bacteria. The percentages of intensity found in bands related to high G+C gram positives increased from 4.5 and 12.6% in the ungrazed microcosms amended with roots and nutrient solution, respectively, to 19.3 and 32.9% in the grazed microcosms. Protozoa reduced the average bacterial cell size in microcosms amended with nutrient solution but not in the treatment amended with roots. Hence, size-selective feeding may explain some but not all of the changes in bacterial community structure. Five different protozoan isolates (Acanthamoeba sp., two species of Cercomonas, Thaumatomonas sp., and Spumella sp.) had different effects on the bacterial communities. This suggests that the composition of protozoan communities is important for the effect of protozoan grazing on bacterial communities.

R?nn, Regin; McCaig, Allison E.; Griffiths, Bryan S.; Prosser, James I.

2002-01-01

166

Effect of protozoan predation on relative abundance of fast- and slow-growing bacteria  

SciTech Connect

Survival of six bacterial species with different growth rates was tested in raw sewage and sewage rendered free of protozoa. When the six species were inoculated at the same densities into sewage containing protozoa, the three slow-growing species were rapidly eliminated, and two of the three fast-growing species survived in detectable numbers. It is suggested that in environments with intense protozoan predation, protozoa may alter composition of bacterial communities by eliminating slow-growing bacteria.

Sinclair, J.L.; Alexander, M.

1989-01-01

167

Phytoplankton, bacterial production and protozoan bacterivory in stratified, brackish-water Lake Shira (Khakasia, Siberia)  

Microsoft Academic Search

Rates of oxygenic and anoxygenic photosynthesis, chemoautotrophic and heterotrophic bacterial production and protozoan bacterivory were measured in the pelagic zone of the stratified brackish-water lake with the purpose to determine the vertical distribution of these processes and to estimate their significance in the functioning of planktonic community of the lake. In midsummer, total daily primary productivity was about 1.3 g C m-2, of

Alexander I. Kopylov; Dmitriy B. Kosolapov; Nadezhda N. Degermendzhy; Tatiana A. Zotina; Anna V. Romanenko

2002-01-01

168

Iron-sulphur clusters, their biosynthesis, and biological functions in protozoan parasites.  

PubMed

Fe-S clusters are ensembles of sulphide-linked di-, tri-, and tetra-iron centres of a variety of metalloproteins that play important roles in reduction and oxidation of mitochondrial electron transport, energy metabolism, regulation of gene expression, cell survival, nitrogen fixation, and numerous other metabolic pathways. The Fe-S clusters are assembled by one of four distinct systems: NIF, SUF, ISC, and CIA machineries. The ISC machinery is a house-keeping system conserved widely from prokaryotes to higher eukaryotes, while the other systems are present in a limited range of organisms and play supplementary roles under certain conditions such as stress. Fe-S cluster-containing proteins and the components required for Fe-S cluster biosynthesis are modulated under stress conditions, drug resistance, and developmental stages. It is also known that a defect in Fe-S proteins and Fe-S cluster biogenesis leads to many genetic disorders in humans, which indicates the importance of the systems. In this review, we describe the biological and physiological significance of Fe-S cluster-containing proteins and their biosynthesis in parasitic protozoa including Plasmodium, Trypanosoma, Leishmania, Giardia, Trichomonas, Entamoeba, Cryptosporidium, Blastocystis, and microsporidia. We also discuss the roles of Fe-S cluster biosynthesis in proliferation, differentiation, and stress response in protozoan parasites. The heterogeneity of the systems and the compartmentalization of Fe-S cluster biogenesis in the protozoan parasites likely reflect divergent evolution under highly diverse environmental niches, and influence their parasitic lifestyle and pathogenesis. Finally, both Fe-S cluster-containing proteins and their biosynthetic machinery in protozoan parasites are remarkably different from those in their mammalian hosts. Thus, they represent a rational target for the development of novel chemotherapeutic and prophylactic agents against protozoan infections. PMID:23876871

Ali, Vahab; Nozaki, Tomoyoshi

2013-01-01

169

Larkinella insperata gen. nov., sp. nov., a bacterium of the phylum 'Bacteroidetes' isolated from water of a steam generator.  

PubMed

A Gram-negative bacterium, designated strain LMG 22510T, was isolated from water of a pharmaceutical company steam generator. The cells had a ring-like and horseshoe-shaped morphology and possessed gliding motility. Phylogenetic analysis of the 16S rRNA gene sequence showed that the strain was a member of the Flexibacter group within the phylum 'Bacteroidetes'; its nearest neighbour was Spirosoma linguale (88.8 % sequence similarity). DNA base content, fatty acid composition and biochemical characteristics were determined. Genotypic and phenotypic data indicated that strain LMG 22510T could not be assigned to any recognized genus; therefore, a novel genus and species is proposed, Larkinella insperata gen. nov., sp. nov., with LMG 22510T (= NCIMB 14103T) as the type strain. PMID:16403892

Vancanneyt, Marc; Nedashkovskaya, Olga I; Snauwaert, Cindy; Mortier, Stefanie; Vandemeulebroecke, Katrien; Hoste, Bart; Dawyndt, Peter; Frolova, Galina M; Janssens, Danielle; Swings, Jean

2006-01-01

170

The Deinococcus-Thermus phylum and the effect of rRNA composition on phylogenetic tree construction  

NASA Technical Reports Server (NTRS)

Through comparative analysis of 16S ribosomal RNA sequences, it can be shown that two seemingly dissimilar types of eubacteria Deinococcus and the ubiquitous hot spring organism Thermus are distantly but specifically related to one another. This confirms an earlier report based upon 16S rRNA oligonucleotide cataloging studies (Hensel et al., 1986). Their two lineages form a distinctive grouping within the eubacteria that deserved the taxonomic status of a phylum. The (partial) sequence of T. aquaticus rRNA appears relatively close to those of other thermophilic eubacteria. e.g. Thermotoga maritima and Thermomicrobium roseum. However, this closeness does not reflect a true evolutionary closeness; rather it is due to a "thermophilic convergence", the result of unusually high G+C composition in the rRNAs of thermophilic bacteria. Unless such compositional biases are taken into account, the branching order and root of phylogenetic trees can be incorrectly inferred.

Weisburg, W. G.; Giovannoni, S. J.; Woese, C. R.

1989-01-01

171

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae) from the snake Philodryas olfersii Lichtenstein (Colubridae) from a coastal habitat in Brazil.  

PubMed

A new coccidian species of the genus Caryospora Léger, 1904 (Protozoa, Apicomplexa, Eimeriidae) is reported from the colubrid snake host Philodryas olfersii Lichtenstein at a coastal area in the State of Rio de Janeiro, south-eastern Brazil. Oöcysts of Caryospora olfersii n. sp. are spherical to sub-spherical, 33.1 × 31.2 ?m, with smooth, colourless, three-layered wall, c.1.4; middle layer lightly striated. Micropyle, oöcyst residuum and polar granule are all absent. Sporocysts are ovoid, 22.9 × 17.4 ?m on average, with one extremity in the shape of a short neck. Stieda body present, 3.2 × 1.3 ?m, sub-Stieda body present, homogeneous, larger than Stieda body, 4.5 × 1.7 ?m. Sporozoites are inserted in a bulky sporocyst residuum. PMID:23673697

Viana, Lúcio A; Winck, Gisele R; Coelho, Cleide D; Flausino, Walter; Duarte Rocha, Carlos F

2013-06-01

172

Coccidia of New World psittaciform birds (Aves: Psittaciformes): Eimeria ararae n. sp. (Apicomplexa: Eimeriidae) from the blue-and-yellow macaw Ara ararauna (Linnaeus).  

PubMed

In the New World, the avian order Psittaciformes comprises 142 species, yet to date only 3 (2%) of the species have been examined for coccidia, and from these only four species of Eimeria Schneider, 1875 have been described. In this study, a new coccidian species (Protozoa: Apicomplexa: Eimeriidae) obtained from the blue-and-yellow macaw Ara ararauna (Linnaeus) is reported from Brazil. Oöcysts of Eimeria ararae n. sp. are ovoidal, measure 28.7 × 20.2 ?m and have a smooth, bi-layered wall c.1.1 ?m thick. Both micropyle and oöcyst residuum are absent, but polar granules are present. Sporocysts are ovoidal and measure 17.0 × 8.3 µm, with knob-like, prominent Stieda body and sporocyst residuum is composed of granules; sub-Stieda body is absent. Sporozoites are vermiform with one refractile body and a nucleus. This is the fifth description of an eimerid coccidian infecting a New World psittaciform bird. PMID:24832188

do Bomfim Lopes, Bruno; Berto, Bruno Pereira; de Carvalho Balthazar, Lianna Maria; Coelho, Cleide Domingues; Neves, Daniel Medeiros; Lopes, Carlos Wilson Gomes

2014-06-01

173

Developing vaccines to control protozoan parasites in ruminants: dead or alive?  

PubMed

Protozoan parasites are among some of the most successful organisms worldwide, being able to live and multiply within a very wide range of hosts. The diseases caused by these parasites cause significant production losses in the livestock sector involving reproductive failure, impaired weight gain, contaminated meat, reduced milk yields and in severe cases, loss of the animal. In addition, some protozoan parasites affecting livestock such as Toxoplasma gondii and Cryptosporidium parvum may also be transmitted to humans where they can cause serious disease. Data derived from experimental models of infection in ruminant species enables the study of the interactions between parasite and host. How the parasite initiates infection, becomes established and multiplies within the host and the critical pathways that may lead to a disease outcome are all important to enable the rational design of appropriate intervention strategies. Once the parasites invade the hosts they induce both innate and adaptive immune responses and the induction and function of these immune responses are critical in determining the outcome of the infection. Vaccines offer green solutions to control disease as they are sustainable, reducing reliance on pharmacological drugs and pesticides. The use of vaccines has multiple benefits such as improving animal health and welfare by controlling animal infections and infestations; improving public health by controlling zoonoses and food borne pathogens in animals; solving problems associated with resistance to acaricides, antibiotics and anthelmintics; keeping animals and the environment free of chemical residues and maintaining biodiversity. All of these attributes should lead to improved sustainability of animal production and economic benefit. Using different protozoan parasitic diseases as examples this paper will discuss various approaches used to develop vaccines to protect against disease in livestock and discuss the relative merits of using live versus killed vaccine preparations. A range of different vaccination targets and strategies will be discussed to help protect against: acute disease, congenital infection and abortion, persistence of zoonotic pathogens in tissues of food animals and passive transfer of immunity to neonates. PMID:21680094

Innes, Elisabeth A; Bartley, Paul M; Rocchi, Mara; Benavidas-Silvan, Julio; Burrells, Alison; Hotchkiss, Emily; Chianini, Francesca; Canton, German; Katzer, Frank

2011-08-01

174

Bioinformatic analysis of beta carbonic anhydrase sequences from protozoans and metazoans  

PubMed Central

Background Despite the high prevalence of parasitic infections, and their impact on global health and economy, the number of drugs available to treat them is extremely limited. As a result, the potential consequences of large-scale resistance to any existing drugs are a major concern. A number of recent investigations have focused on the effects of potential chemical inhibitors on bacterial and fungal carbonic anhydrases. Among the five classes of carbonic anhydrases (alpha, beta, gamma, delta and zeta), beta carbonic anhydrases have been reported in most species of bacteria, yeasts, algae, plants, and particular invertebrates (nematodes and insects). To date, there has been a lack of knowledge on the expression and molecular structure of beta carbonic anhydrases in metazoan (nematodes and arthropods) and protozoan species. Methods Here, the identification of novel beta carbonic anhydrases was based on the presence of the highly-conserved amino acid sequence patterns of the active site. A phylogenetic tree was constructed based on codon-aligned DNA sequences. Subcellular localization prediction for each identified invertebrate beta carbonic anhydrase was performed using the TargetP webserver. Results We verified a total of 75 beta carbonic anhydrase sequences in metazoan and protozoan species by proteome-wide searches and multiple sequence alignment. Of these, 52 were novel, and contained highly conserved amino acid residues, which are inferred to form the active site in beta carbonic anhydrases. Mitochondrial targeting peptide analysis revealed that 31 enzymes are predicted with mitochondrial localization; one was predicted to be a secretory enzyme, and the other 43 were predicted to have other undefined cellular localizations. Conclusions These investigations identified 75 beta carbonic anhydrases in metazoan and protozoan species, and among them there were 52 novel sequences that were not previously annotated as beta carbonic anhydrases. Our results will not only change the current information in proteomics and genomics databases, but will also suggest novel targets for drugs against parasites.

2014-01-01

175

Composition of benthic protozoan communities along a depth transect in the eastern Mediterranean Sea  

NASA Astrophysics Data System (ADS)

The benthic protozoans were investigated along a transect in the eastern Mediterranean Sea from the Ionian to the Levantine Sea. Sediment samples were taken during Meteor cruise 25/1 in May and June 1993 at water depths of between 156 and 4617 m with a box corer and a multiple corer. A semi-quantitative cultivation technique was applied by placing sediment in petri dishes and diluting with sterile biotope water. Microscopic analyses of the protozoan taxa were conducted immediately after sampling, and then daily after enrichment with organic substrate. A total of 134 protozoan morphospecies were recorded, including 87 flagellates, 12 naked amoebae and 35 ciliates. 58% of the species could be attributed to genera known from shallow waters, demonstrating the wide distribution of these taxa. The number of recorded species per location ranged from 0 to 35 and decreased with increasing water depth. At stations deeper 1300 m very low species numbers as well as low potential abundances were recorded. Qualitative changes in the taxonomic composition with increasing depth were recorded as a decrease in the proportion of amoebae and euglenid flagellates and as an increase in the proportion of dinoflagellates. Ciliates were found down to a depth of 4260 m. The number of species was also dependent on the chloroplastic pigment equivalent (CPE), indicating a dependency on sedimented phytodetritus. The observed species included picophagous species, which feed mostly on bacteria, as well as nano- and microphagous species, which generally feed on protists, suggesting the existence of several trophic levels within the deep sea microbial food web.

Hausmann, K.; Hülsmann, N.; Polianski, I.; Schade, S.; Weitere, M.

2002-11-01

176

The Cre/loxP system in Giardia lamblia: genetic manipulations in a binucleate tetraploid protozoan.  

PubMed

The bacteriophage-derived Cre/loxP system is a valuable tool that has revolutionised genetic and cell biological research in many organisms. We implemented this system in the intestinal parasite Giardia lamblia, an evolutionarily diverged protozoan whose binucleate and tetraploid genome organisation severely limits the application of reverse genetic approaches. We show that Cre-recombinase is functionally expressed in G. lamblia and demonstrate "recycling" of selectable markers. Providing the means for more complex and versatile genetic modifications, this technique massively increases the scope of functional investigations in G. lamblia and other protozoa with similar limitations with respect to genetic manipulation. PMID:24747534

Wampfler, Petra B; Faso, Carmen; Hehl, Adrian B

2014-07-01

177

Macrophage Migration Inhibitory Factor (MIF): A Key Player in Protozoan Infections  

PubMed Central

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine produced by the pituitary gland and multiple cell types, including macrophages (Mø), dendritic cells (DC) and T-cells. Upon releases MIF modulates the expression of several inflammatory molecules, such as TNF-?, nitric oxide and cyclooxygenase 2 (COX-2). These important MIF characteristics have prompted investigators to study its role in parasite infections. Several reports have demonstrated that MIF plays either a protective or deleterious role in the immune response to different pathogens. Here, we review the role of MIF in the host defense response to some important protozoan infections.

de Dios Rosado, Juan; Rodriguez-Sosa, Miriam

2011-01-01

178

Protozoans in two southeastern blackwater rivers and their importance to trophic transfer  

Microsoft Academic Search

Abstract Protozoan,population,densities,in the sixth-order Ogeechee,River and,fourth-order Black Creek ranged,from,6 x lo4 to 11 x 10” flagellates liter-l and,0 to 1.5 x,lo5 ciliates liter-’ over,a 12- month,period. These numbers,approximate,those,reported,for various,marine,and,freshwater habitats. A microcosm,study with,Ogeechee,River water,showed,a density,increase,from,4 x lo5 to 9 x lo6 flagellates liter -I and 7 x 10) to 4 x lo5 ciliates liter-’ in 2 d, representing an estimated

LESLIE A. CARLOUGH; JUDY L. MEYER

1989-01-01

179

Host-parasite interactions: Marine bivalve molluscs and protozoan parasites, Perkinsus species.  

PubMed

This review assesses and examines the work conducted to date concerning host and parasite interactions between marine bivalve molluscs and protozoan parasites, belonging to Perkinsus species. The review focuses on two well-studied host-parasite interaction models: the two clam species, Ruditapes philippinarum and R. decussatus, and the parasite Perkinsus olseni, and the eastern oyster, Crassostrea virginica, and the parasite Perkinsus marinus. Cellular and humoral defense responses of the host in combating parasitic infection, the mechanisms (e.g., antioxidant enzymes, extracellular products) employed by the parasite in evading host defenses as well as the role of environmental factors in modulating the host-parasite interactions are described. PMID:23871855

Soudant, Philippe; E Chu, Fu-Lin; Volety, Aswani

2013-10-01

180

Transfection and transient expression of chloramphenicol acetyltransferase gene in the protozoan parasite Entamoeba histolytica.  

PubMed Central

Hybrid plasmids were constructed and used for successful transfection and transient expression of the chloramphenicol acetyltransferase (CAT) gene in the protozoan parasite Entamoeba histolytica. Transfection was performed by electroporation of the amebae in a potassium phosphate-based buffer under conditions of 3000 V/cm and 25 microF, resulting in a time constant of 0.4 ms. Expression of CAT activity was achieved with constructs in which the CAT coding region was flanked by untranslated upstream and downstream sequences of E. histolytica genes. Highest activity was detected after culturing transfected cells for 48 hr. Activity was found to be proportional to the amount of DNA transfected. Images

Nickel, R; Tannich, E

1994-01-01

181

Thermoflavifilum aggregans gen. nov., sp. nov., a thermophilic and slightly halophilic filamentous bacterium from the phylum Bacteroidetes.  

PubMed

A strictly aerobic, thermophilic, moderately acidophilic, non-spore-forming bacterium, strain P373(T), was isolated from geothermally heated soil at Waikite, New Zealand. Cells were filamentous rods, 0.2-0.4 µm in diameter and grew in chains up to 80 µm in length. On the basis of 16S rRNA gene sequence similarity, strain P373(T) was shown to belong to the family Chitinophagaceae (class Sphingobacteriia) of the phylum Bacteroidetes, with the most closely related cultivated strain, Chitinophaga pinensis UQM 2034(T), having 87.6?% sequence similarity. Cells stained Gram-negative, and were catalase- and oxidase-positive. The major fatty acids were i-15?:?0 (10.8?%), i-17?:?0 (24.5?%) and i-17?:?0 3-OH (35.2?%). Primary lipids were phosphatidylethanolamine, two unidentified aminolipids and three other unidentified polar lipids. The presence of sulfonolipids (N-acyl-capnines) was observed in the total lipid extract by mass spectrometry. The G+C content of the genomic DNA was 47.3 mol% and the primary respiratory quinone was MK-7. Strain P373(T) grew at 35-63 °C with an optimum temperature of 60 °C, and at pH 5.5-8.7 with an optimum growth pH of 7.3-7.4. NaCl tolerance was up to 5?% (w/v) with an optimum of 0.1-0.25?% (w/v). Cell colonies were non-translucent and pigmented vivid yellow-orange. Cells displayed an oxidative chemoheterotrophic metabolism. The distinct phylogenetic position and the phenotypic characteristics separate strain P373(T) from all other members of the phylum Bacteroidetes and indicate that it represents a novel species in a new genus, for which the name Thermoflavifilum aggregans gen. nov., sp. nov. is proposed. The type strain of the type species is P373(T) (?=?ICMP 20041(T)?=?DSM 27268(T)). PMID:24425740

Anders, Heike; Dunfield, Peter F; Lagutin, Kirill; Houghton, Karen M; Power, Jean F; Mackenzie, Andrew D; Vyssotski, Mikhail; Ryan, Jason L J; Hanssen, Eric G; Moreau, John W; Stott, Matthew B

2014-04-01

182

Breast-Feeding Protects Infantile Diarrhea Caused by Intestinal Protozoan Infections  

PubMed Central

This study investigated the effect of breast-feeding in protection against protozoan infection in infants with persistent diarrhea. Infants were classified into 2 groups; 161 breast-fed infants and the same number of non-breast-fed infants. Microscopic examinations of stool were done for detection of parasites and measuring the intensity of infection. Moreover, serum levels of IgE and TNF-? were measured by ELISA. Cryptosporidium spp., Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Blastocystis sp. were demonstrated in infants with persistent diarrhea. The percentage of protozoan infections was significantly lower in breast-fed infants than that in the non-breast-fed infants. The levels of IgE and TNF-? were significantly lower in the breast-fed group than in the non-breast-fed group. There were significant positive associations between the serum levels of IgE and TNF-? and the intensity of parasite infection in the breast-fed group. It is suggested that breast-feeding has an attenuating effect on the rate and intensity of parasite infection.

Belal, Usama Salah; Abdellatif, Manal Zaki Mohamed; Naoi, Koji; Norose, Kazumi

2013-01-01

183

Protozoan predation as a mechanism for the removal of cryptosporidium oocysts from wastewaters in constructed wetlands.  

PubMed

The removal of the protozoan parasite, Cryptosporidium parvum, from wastewaters is becoming of increasing importance in the UK, especially since contamination of raw waters by sewage effluents has been implicated in major waterborne outbreaks of cryptosporidiosis in recent years. Compared to conventional wastewater-treatment processes, constructed wetlands have demonstrated favourable removal rates for Cryptosporidium oocysts. The removal mechanisms, however, remain unknown. Predation by free-living ciliated protozoa, which are commonly found in constructed wetlands, was investigated as a possible mechanism for oocyst removal. In laboratory feeding experiments, ciliates (Euplotes patella, Stylonychia mytilus, Paramecium caudatum and an unidentified wetland ciliate species), were exposed to doses ranging from 10 to 10(6) oocysts/ml for between 5 and 60 minutes. Ciliate predatory activities were assessed by enumerating fluorescently labelled ingested oocysts using epifluorescence microscopy. Oocysts were found to be ingested by all species investigated. Paramecium demonstrated the highest mean ingestion rates (up to 170 oocysts/hr) followed by Stylonychia (up to 60 oocysts/hour). Euplotes and the wetland ciliate had lower mean grazing rates (4 and 10 oocysts/hr respectively). These results indicate that protozoan predation may be an important factor in the removal of Cryptosporidium oocysts from wastewaters in constructed wetlands. PMID:11804094

Stott, R; May, E; Matsushita, E; Warren, A

2001-01-01

184

Effect of anaerobic digestion on oocysts of the protozoan Eimeria tenella.  

PubMed Central

The effect of anaerobic digestion of poultry waste on oocysts of the protozoan Eimeria tenella, a common enteric pathogen that causes coccidiosis in poultry, was investigated in this study. Thermophilic (50 degrees C) and mesophilic (35 degrees C) anaerobic digestors, with poultry manure as the substrate, were inoculated with the oocysts. The oocysts were damaged during anaerobic digestion, as determined by morphological change and loss of their ability to sporulate. The recovered oocysts were tested for their infectivity in young chicks, as measured by body weight gain, mortality, and cecal lesions. Oocysts lost all their infectivity during thermophilic digestion, while oocysts subjected to mesophilic digestion remained moderately infective in comparison with untreated oocysts, which produced severe coccidiosis, high mortality, and low body weight gain in chicks. Oocysts were inactivated at 50 degrees C when they were suspended in digestor fluid or saline. Inactivation at 35 degrees C was significantly stronger in the digestor fluid than in the saline, which implied that factors other than temperature were involved in the lethal effect of anaerobic digestion on protozoan oocysts. In this study we demonstrated that the treatment of animal waste by anaerobic digestion, especially at a thermophilic temperature, has the benefits of pathogen control and protection of human and animal health in a farm environment. Images

Lee, M R; Shih, J C

1988-01-01

185

Breast-feeding protects infantile diarrhea caused by intestinal protozoan infections.  

PubMed

This study investigated the effect of breast-feeding in protection against protozoan infection in infants with persistent diarrhea. Infants were classified into 2 groups; 161 breast-fed infants and the same number of non-breast-fed infants. Microscopic examinations of stool were done for detection of parasites and measuring the intensity of infection. Moreover, serum levels of IgE and TNF-? were measured by ELISA. Cryptosporidium spp., Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Blastocystis sp. were demonstrated in infants with persistent diarrhea. The percentage of protozoan infections was significantly lower in breast-fed infants than that in the non-breast-fed infants. The levels of IgE and TNF-? were significantly lower in the breast-fed group than in the non-breast-fed group. There were significant positive associations between the serum levels of IgE and TNF-? and the intensity of parasite infection in the breast-fed group. It is suggested that breast-feeding has an attenuating effect on the rate and intensity of parasite infection. PMID:24327776

Abdel-Hafeez, Ekhlas Hamed; Belal, Usama Salah; Abdellatif, Manal Zaki Mohamed; Naoi, Koji; Norose, Kazumi

2013-10-01

186

Crystal structures and proposed structural/functional classification of three protozoan proteins from the isochorismatase superfamily  

PubMed Central

We have determined the crystal structures of three homologous proteins from the pathogenic protozoans Leishmania donovani, Leishmania major, and Trypanosoma cruzi. We propose that these proteins represent a new subfamily within the isochorismatase superfamily (CDD classification cd004310). Their overall fold and key active site residues are structurally homologous both to the biochemically well-characterized N-carbamoylsarcosine-amidohydrolase, a cysteine hydrolase, and to the phenazine biosynthesis protein PHZD (isochorismase), an aspartyl hydrolase. All three proteins are annotated as mitochondrial-associated ribonuclease Mar1, based on a previous characterization of the homologous protein from L. tarentolae. This would constitute a new enzymatic activity for this structural superfamily, but this is not strongly supported by the observed structures. In these protozoan proteins, the extended active site is formed by inter-subunit association within a tetramer, which implies a distinct evolutionary history and substrate specificity from the previously characterized members of the isochorismatase superfamily. The characterization of the active site is supported crystallographically by the presence of an unidentified ligand bound at the active site cysteine of the T. cruzi structure.

Caruthers, Jonathan; Zucker, Frank; Worthey, Elizabeth; Myler, Peter J.; Buckner, Fred; Van Voorhuis, Wes; Mehlin, Chris; Boni, Erica; Feist, Tiffany; Luft, Joseph; Gulde, Stacey; Lauricella, Angela; Kaluzhniy, Oleksandr; Anderson, Lori; Le Trong, Isolde; Holmes, Margaret A.; Earnest, Thomas; Soltis, Michael; Hodgson, Keith O.; Hol, Wim G.J.; Merritt, Ethan A.

2005-01-01

187

Recurrent wheezing is associated with intestinal protozoan infections in Warao Amerindian children in Venezuela: a cross-sectional survey  

PubMed Central

Background While in developed countries the prevalence of allergic diseases is rising, inflammatory diseases are relatively uncommon in rural developing areas. High prevalence rates of helminth and protozoan infections are commonly found in children living in rural settings and several studies suggest an inverse association between helminth infections and allergies. No studies investigating the relationship between parasitic infections and atopic diseases in rural children of developing countries under the age of 2 years have been published so far. We performed a cross-sectional survey to investigate the association of helminth and protozoan infections and malnutrition with recurrent wheezing and atopic eczema in Warao Amerindian children in Venezuela. Methods From August to November 2012, 229 children aged 0 to 2 years residing in the Orinoco Delta in Venezuela were enrolled. Data were collected through standardized questionnaires and physical examination, including inspection of the skin and anthropometric measurements. A stool sample was requested from all participants and detection of different parasites was performed using microscopy and real time polymerase chain reaction (PCR). Results We observed high prevalence rates of atopic eczema and recurrent wheezing, respectively 19% and 23%. The prevalence of helminth infections was 26% and the prevalence of protozoan infections was 59%. Atopic eczema and recurrent wheezing were more frequently observed in stunted compared with non-stunted children in multivariable analysis (OR 4.3, 95% CI 1.3 – 13.6, p?=?0.015 and OR 4.5, 95% CI 0.97 – 21.2, p?=?0.055). Furthermore, recurrent wheezing was significantly more often observed in children with protozoan infections than in children without protozoan infections (OR 6.7, 95% CI 1.5 – 30.5). Conclusions High prevalence rates of atopic eczema and recurrent wheezing in Warao Amerindian children under 2 years of age were related to stunting and intestinal protozoan infections respectively. Helminth infections were not significantly associated with either atopic eczema or recurrent wheezing.

2014-01-01

188

[Morphology and diagnosis of the oral protozoans Trichomonas tenax and Entamoeba gingivalis using the Giemsa-Romanovsky stain].  

PubMed

In the microscopic diagnosis of Trichomonas tenax and Entamoeba gingivalis is the technically and time not demanding native preparation of a culture, in which both protozoans can be detected according to their typical motility, determining. In the permanent preparation of the culture stained according to Giemsa-Romanovsky, which has also documentary character, are all of the characteristic cell organelles stainable, enabling so their detection without their typical motility. Staining according to Giemsa-Romanovsky is technically simple and not time consuming, not very laborious, low cost and the coloration is permanent, that means optimal for the diagnostic of oral protozoans in permanent preparations. (Fig. 5, Ref. 4.) PMID:9919761

Vráblic, J; Vodrázka, J; Tomová, S; Staník, R; Catár, G

1998-11-01

189

Pyramidobacter piscolens gen. nov., sp. nov., a member of the phylum 'Synergistetes' isolated from the human oral cavity  

PubMed Central

Four strains of anaerobic, Gram-negative bacilli isolated from the human oral cavity were subjected to a comprehensive range of phenotypic and genotypic tests and were found to comprise a homogeneous group distinct from any species with validly published names. 16S rRNA and 23S rRNA gene sequence analyses and DNA–DNA reassociation data revealed that the strains constituted a novel group within the phylum ‘Synergistetes’ and were most closely related to Jonquetella anthropi. Two libraries of randomly cloned DNA were prepared from strain W5455T and were sequenced to provide a genome survey as a resource for metagenomic studies. A new genus and novel species, Pyramidobacter piscolens gen. nov., sp. nov., is proposed to accommodate these strains. The genus Pyramidobacter comprises strains that are anaerobic, non-motile, asaccharolytic bacilli that produce acetic and isovaleric acids and minor to trace amounts of propionic, isobutyric, succinic and phenylacetic acids as end products of metabolism. P. piscolens gen. nov., sp. nov. produced hydrogen sulphide but was otherwise largely biochemically unreactive. Growth was stimulated by the addition of glycine to broth media. The G+C content of the DNA of the type strain was 59?mol%. The type strain of Pyramidobacter piscolens sp. nov. is W5455T (=DSM 21147T=CCUG 55836T).

Downes, Julia; Vartoukian, Sonia R.; Dewhirst, Floyd E.; Izard, Jacques; Chen, Tsute; Yu, Wen-Han; Sutcliffe, Iain C.; Wade, William G.

2009-01-01

190

Sediminibacterium salmoneum gen. nov., sp. nov., a member of the phylum Bacteroidetes isolated from sediment of a eutrophic reservoir.  

PubMed

Strain NJ-44(T), isolated from sediment of the eutrophic Guanting Reservoir in Beijing (China), was subjected to a taxonomic study using a polyphasic approach. The strain was aerobic, with salmon-pink-pigmented colonies on R2A agar. Cells were single, Gram-negative rods, motile by gliding. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain NJ-44(T) belonged to the phylum Bacteroidetes, with Terrimonas ferruginea ATCC 13524(T) (90.8% similarity), Terrimonas lutea DY(T) (90.5%) and Niabella aurantiaca R2A15-11(T) (89.1%) as its closest relatives. Strain NJ-44(T) was clearly differentiated from members of the genera Terrimonas and Niabella in its DNA G+C content (40.6 mol%) and its major fatty acids, iso-C(15:1) G, iso-C(15:0), anteiso-C(15:0), iso-C(16:0) 3-OH, iso-C(17:0) 3-OH, anteiso-C(15:1) A and iso-C(15:0) 3-OH. It is proposed that strain NJ-44(T) represents a novel genus and species, named Sediminibacterium salmoneum gen. nov., sp. nov. The type strain of Sediminibacterium salmoneum is strain NJ-44(T) (=CGMCC 1.6845(T) =NBRC 103935(T)). PMID:18768628

Qu, Jian-Hang; Yuan, Hong-Li

2008-09-01

191

Characterization of a new marine nitrite oxidizing bacterium, Nitrospina watsonii sp. nov., a member of the newly proposed phylum "Nitrospinae".  

PubMed

Nitrite oxidizing bacteria are an integral part of the nitrogen cycle in marine waters, but the knowledge about their diversity is limited. Recently, a high abundance of Nitrospina-like 16S rRNA gene sequences has been detected in oceanic habitats with low oxygen content by molecular methods. Here, we describe a new strain of Nitrospina, which was sampled in 100m depth from the Black Sea. It coexisted with a not-yet cultivated chemoorganotrophic gammaproteobacterium and could be purified by classical isolation methods including Percoll density gradient centrifugation. The new Nitrospina-like bacterium grew lithoautotrophically at 28°C in diluted seawater supplemented with inorganic salts and nitrite. Gram-negative rods were characterized morphologically, physiologically and partly biochemically. The 16S rRNA gene of the new strain of Nitrospina is 97.9% similar to the described species N. gracilis and DNA/DNA hybridization experiments revealed a relatedness of 30.0%. The data from both Nitrospina species and environmental clones were used for an extensive 16S rRNA based phylogenetic study applying high quality filtering. Treeing analyses confirm the newly defined phylum status for "Nitrospinae" [18]. The results of phylogenetic and genotypic analyses support the proposal of a novel species Nitrospina watsonii sp. nov. (type strain 347(T), LMG 27401(T), NCIMB 14887(T)). PMID:24581679

Spieck, Eva; Keuter, Sabine; Wenzel, Thilo; Bock, Eberhard; Ludwig, Wolfgang

2014-05-01

192

Pontibacter xinjiangensis sp. nov., in the phylum 'Bacteroidetes', and reclassification of [Effluviibacter] roseus as Pontibacter roseus comb. nov.  

PubMed

A novel strain, designated 311-10(T), isolated from soil of Xinjiang, China, was characterized by using a polyphasic taxonomic approach. The isolate was Gram-negative, aerobic, rod-shaped, non-motile, oxidase-negative and catalase-positive. The predominant menaquinone of strain 311-10(T) was MK-7 and the genomic DNA G+C content was 47.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate formed a cluster with the genera Pontibacter and [Effluviibacter] in the phylum 'Bacteroidetes', with sequence similarities of 93.9-95.6 %. Phylogenetic evidence and the results of phenotypic, genotypic and chemotaxonomic analyses support the reclassification of [Effluviibacter] roseus as Pontibacter roseus comb. nov. (type strain, SRC-1(T)=MTCC 7260(T)=DSM 17521(T)) and the establishment of a novel species, Pontibacter xinjiangensis sp. nov., with strain 311-10(T) (=CCTCC AB 207200(T)=NRRL B-51335(T)) as the type strain. PMID:19648348

Wang, Yang; Zhang, Kundi; Cai, Feng; Zhang, Lei; Tang, Yali; Dai, Jun; Fang, Chengxiang

2010-01-01

193

Geoarchaeota: a new candidate phylum in the Archaea from high-temperature acidic iron mats in Yellowstone National Park  

SciTech Connect

Geothermal systems in Yellowstone National Park (YNP) provide an outstanding opportunity to understand the origin and evolution of metabolic processes necessary for life in extreme environments including low pH, high temperature, low oxygen and elevated concentrations of reduced iron. Previous phylogenetic studies of acidic ferric iron mats from YNP have revealed considerable diversity of uncultivated and undescribed archaea. The goal of this study was to obtain replicate de novo genome assemblies for a dominant archaeal population inhabiting acidic iron oxide mats in YNP. Detailed analysis of conserved ribosomal and informational processing genes indicate that the replicate assemblies represent a new phylum-level lineage referred to here as 'novel archaeal group 1 (NAG1)'. The NAG1 organisms contain pathways necessary for the catabolism of peptides and complex carbohydrates as well as a bacterial-like Form I CO dehydrogenase complex likely used for energy conservation. Moreover, this novel population contains genes involved in metabolism of oxygen including a Type A heme copper oxidase, a bd-type terminal oxidase and a putative oxygen sensing protoglobin. NAG1 has a variety of unique bacterial-like cofactor biosynthesis and transport genes and a Type3-like CRISPR system. Discovery of NAG1 is critical to our understanding of microbial community structure and function in extant thermophilic iron mats of YNP, and will provide insight regarding the evolution of Archaea in early Earth environments that may have important analogues active in YNP today.

Kozubal, Mark; Romine, Margaret F.; Jennings, Ryan; Jay, Z.; Tringe, Susannah G.; Rusch, Douglas B.; Beam, Jake; McCue, Lee Ann; Inskeep, William P.

2013-03-01

194

Platyhelminth Venom Allergen-Like (VAL) proteins: revealing structural diversity, class-specific features and biological associations across the phylum  

PubMed Central

SUMMARY During platyhelminth infection, a cocktail of proteins is released by the parasite to aid invasion, initiate feeding, facilitate adaptation and mediate modulation of the host immune response. Included amongst these proteins is the Venom Allergen-Like (VAL) family, part of the larger sperm coating protein/Tpx-1/Ag5/PR-1/Sc7 (SCP/TAPS) superfamily. To explore the significance of this protein family during Platyhelminthes development and host interactions, we systematically summarize all published proteomic, genomic and immunological investigations of the VAL protein family to date. By conducting new genomic and transcriptomic interrogations to identify over 200 VAL proteins (228) from species in all 4 traditional taxonomic classes (Trematoda, Cestoda, Monogenea and Turbellaria), we further expand our knowledge related to platyhelminth VAL diversity across the phylum. Subsequent phylogenetic and tertiary structural analyses reveal several class-specific VAL features, which likely indicate a range of roles mediated by this protein family. Our comprehensive analysis of platyhelminth VALs represents a unifying synopsis for understanding diversity within this protein family and a firm context in which to initiate future functional characterization of these enigmatic members.

CHALMERS, IAIN W.; HOFFMANN, KARL F.

2012-01-01

195

Group-specific PCR primers for the phylum Acidobacteria designed based on the comparative analysis of 16S rRNA gene sequences  

Microsoft Academic Search

We performed a comprehensive phylogenetic analysis of the phylum Acidobacteria and developed novel, group-specific PCR primers for Acidobacteria and its class-level subgroups. Acidobacterial 16S rRNA gene sequences deposited in the RDP database were used to construct a local database then subsequently analyzed. A total of 556 phylotypes were observed and the majority of the phylotypes belonged to five major subgroups

Sang-Hoon Lee; Jae-Chang Cho

2011-01-01

196

Effect of pH on Isolation and Distribution of Members of Subdivision 1 of the Phylum Acidobacteria Occurring in Soil  

Microsoft Academic Search

The pH strongly influenced the development of colonies by members of subdivision 1 of the phylum Acidobacteria on solid laboratory media. Significantly more colonies of this group formed at pH 5.5 than at pH 7.0. At pH 5.5, 7 to 8% of colonies that formed on plates that were incubated for 4 months were formed by subdivision 1 acidobacteria. These

Michelle Sait; Kathryn E. R. Davis; Peter H. Janssen

2006-01-01

197

The Ascomycota tree of life: a phylum-wide phylogeny clarifies the origin and evolution of fundamental reproductive and ecological traits  

Microsoft Academic Search

We present a 6-gene, 420-species maximum-likelihood phylogeny of Ascomycota, the largest phylum of Fungi. This analysis is the most taxonomically complete to date with species sampled from all 15 currently circumscribed classes. A number of superclass-level nodes that have previously evaded resolution and were unnamed in classifications of the Fungi are resolved for the first time. Based on the 6-gene

C. L. Schoch; G.-H. Sung; F. López-Giráldez; J. P. Townsend; J. Miadlikowska; V. Hofstetter; B. Robbertse; P. Brandon Matheny; F. Kauff; Z. Wang; C. Gueidan; R. M. Andrie; K. Trippe; L. M. Ciufetti; A. Wynns; E. Fraker; B. P. Hodkinson; G. Bonito; J. Z. Groenewald; M. Arzanlou; Hoog de G. S; P. W. Crous; D. Hewitt; D. H. Pfister; K. Peterson; M. Gryzenhout; M. J. Wingfield; A. Aptroot; S.-O. Suh; M. Blackwell; D. M. Hillis; G. W. Griffith; L. A. Castlebury; A. Y. Rossman; H. T. Lumbsch; R. Lücking; B. Büdel; A. Rauhut; P. Diederich; D. Ertz; D. M. Geiser; K. Hosaka; P. Inderbitzin; J. Kohlmeyer; B. Volkmann-Kohlmeyer; L. Mostert; K. O'Donnell; H. Sipman; J. D. Rogers; R. A. Shoemaker; J. Sugiyama; R. C. Summerbell; W. Untereiner; P. R. Johnston; S. Stenroos; A. Zuccaro; P. S. Dyer; P. D. Crittenden; M. S. Cole; K. Hansen; J. M. Trappe; R. Yahr; F. Lutzoni; J. W. Spatafora

2009-01-01

198

Novel PCR Primers for the Archaeal Phylum Thaumarchaeota Designed Based on the Comparative Analysis of 16S rRNA Gene Sequences  

PubMed Central

Based on comparative phylogenetic analysis of 16S rRNA gene sequences deposited in an RDP database, we constructed a local database of thaumarchaeotal 16S rRNA gene sequences and developed a novel PCR primer specific for the archaeal phylum Thaumarchaeota. Among 9,727 quality-filtered (chimeral-checked, size >1.2 kb) archaeal sequences downloaded from the RDP database, 1,549 thaumarchaeotal sequences were identified and included in our local database. In our study, Thaumarchaeota included archaeal groups MG-I, SAGMCG-I, SCG, FSCG, RC, and HWCG-III, forming a monophyletic group in the phylogenetic tree. Cluster analysis revealed 114 phylotypes for Thaumarchaeota. The majority of the phylotypes (66.7%) belonged to the MG-I and SCG, which together contained most (93.9%) of the thaumarchaeotal sequences in our local database. A phylum-directed primer was designed from a consensus sequence of the phylotype sequences, and the primer’s specificity was evaluated for coverage and tolerance both in silico and empirically. The phylum-directed primer, designated THAUM-494, showed >90% coverage for Thaumarchaeota and <1% tolerance to non-target taxa, indicating high specificity. To validate this result experimentally, PCRs were performed with THAUM-494 in combination with a universal archaeal primer (ARC917R or 1017FAR) and DNAs from five environmental samples to construct clone libraries. THAUM-494 showed a satisfactory specificity in empirical studies, as expected from the in silico results. Phylogenetic analysis of 859 cloned sequences obtained from 10 clone libraries revealed that >95% of the amplified sequences belonged to Thaumarchaeota. The most frequently sampled thaumarchaeotal subgroups in our samples were SCG, MG-I, and SAGMCG-I. To our knowledge, THAUM-494 is the first phylum-level primer for Thaumarchaeota. Furthermore, the high coverage and low tolerance of THAUM-494 will make it a potentially valuable tool in understanding the phylogenetic diversity and ecological niche of Thaumarchaeota.

Hong, Jin-Kyung; Kim, Hye-Jin; Cho, Jae-Chang

2014-01-01

199

Molecular and parasitological survey of Hepatozoon canis (Apicomplexa: Hepatozoidae) in dogs from rural area of Sao Paulo state, Brazil.  

PubMed

Hepatozoon canis is a protozoan that infects dogs and is transmitted by the ingestion of the brown dog tick, Rhipicephalus sanguineus. Two distinct species of Hepatozoon genus can infect dogs, H. canis and H. americanum. Routine tests to detect the disease are based on direct examination of gametocytes on Giemsa-stained blood smears. The objectives of this study were the investigation of infection prevalence in rural area dogs, the comparison of diagnostics by blood smear examination and polymerase chain reaction (PCR), and the association of infection with tick infestation. Blood smears, collected by puncture of the cephalic vein and ear margin capillary bed from 150 dogs, were examined. This technique detected 17 positive animals (11.3%), with 14 (9.3%) in peripheral blood and seven (4.7%) in cephalic vein blood. PCR tests detected 80 (53.3%) positive animals. R. sanguineus and Amblyomma spp. were found in 36 of the dogs (24%), in equal proportions. The identified species for Amblyomma genus were A. cajennense and A. ovale. Data analysis showed that PCR was much more sensitive when compared to blood smear examination. Hepatozoon species was previously identified as closely related to H. canis. PMID:18188597

Rubini, Adriano Stefani; dos Santos Paduan, Karina; Von Ah Lopes, Viviane; O'Dwyer, Lucia Helena

2008-04-01

200

Integration of tools and resources for display and analysis of genomic data for protozoan parasites.  

PubMed

Centralisation of tools for analysis of genomic data is paramount in ensuring that research is always carried out on the latest currently available data. As such, World Wide Web sites providing a range of online analyses and displays of data can play a crucial role in guaranteeing consistency of in silico work. In this respect, the protozoan parasite research community is served by several resources, either focussing on data and tools for one species or taking a broader view and providing tools for analysis of data from many species, thereby facilitating comparative studies. In this paper, we give a broad overview of the online resources available. We then focus on the GeneDB project, detailing the features and tools currently available through it. Finally, we discuss data curation and its importance in keeping genomic data 'relevant' to the research community. PMID:15826641

Aslett, Martin; Mooney, Paul; Adlem, Ellen; Berriman, Matthew; Berry, Andrew; Hertz-Fowler, Christiane; Ivens, Alasdair C; Kerhornou, Arnaud; Parkhill, Julian; Peacock, Chris S; Wood, Valerie; Rajandream, Marie-Adele; Barrell, Bart; Tivey, Adrian

2005-04-30

201

Common strategies for antigenic variation by bacterial, fungal and protozoan pathogens  

PubMed Central

The complex relationships between infectious organisms and their hosts often reflect the continuing struggle of the pathogen to proliferate and spread to new hosts, and the need of the infected individual to control and potentially eradicate the infecting population. In the case of mammals and the pathogens that infect them, a veritable “arms race” has ensued. A highly adapted immune system has evolved to control the proliferation of infectious organisms and the pathogens have developed correspondingly complex genetic systems to evade this immune response. Here, we review how bacterial, protozoan and fungal pathogens from distant evolutionary lineages have evolved surprisingly similar mechanisms of antigenic variation to avoid eradication by the host immune system and thus maintain persistent infections, thereby ensuring their transmission to new hosts.

Lukehart, Sheila A.; Stringer, James R.

2013-01-01

202

Role of extracellular nucleotides in the immune response against intracellular bacteria and protozoan parasites  

PubMed Central

Extracellular nucleotides are danger signals involved in recognition and control of intracellular pathogens. They are an important component of the innate immune response against intracellular pathogens, inducing the recruitment of inflammatory cells, stimulating secretion of cytokines, and producing inflammatory mediators such as reactive oxygen species (ROS) and nitric oxide (NO). In the case of extracellular ATP, some of the immune responses are mediated through activation of the NLRP3 inflammasome and secretion of the cytokine, interleukin-1? (IL-1?), through a mechanism dependent on ligation of the P2X7 receptor. Here we review the role of extracellular nucleotides as sensors of intracellular bacteria and protozoan parasites, and discuss how these pathogens manipulate purinergic signaling to diminish the immune response against infection.

Coutinho-Silva, Robson; Ojcius, David M.

2014-01-01

203

Phototherapies: photosensitized inactivation of viral and protozoan infectious agents and potential application in blood banking  

NASA Astrophysics Data System (ADS)

More than 10 million units of human blood components are processed annually in the United States. Although donor screening and testing have greatly lowered the risk of transmission of viral and protozoan infectious agents, additional sterilization procedures which also preserve blood component function would be of significant value. Use of UV-A and visible-light-range photosensitizers for sterilization of blood platelets and red blood cells, respectively, is currently being aggressively investigated in laboratory-scale optical-mechanical systems. With successful demonstration of the efficacy and safety of these sterilization techniques, implementation in the blood bank setting will require scale-up to optical-mechanical systems capable of handling approximately 25,000 units daily in 500 - 1,000 blood banks in the United States.

Judy, Millard M.; Matthews, James Lester; Sogandares-Bernal, Franklin M.; Newman, Joseph T.; Chanh, Tran C.; Marengo-Rowe, Alain J.

1992-06-01

204

Protozoan ciliate epibionts on the freshwater shrimp Caridina (Crustacea, Decapoda, Atyidae) from the Malili lake system on Sulawesi (Indonesia)  

Microsoft Academic Search

Protozoan ciliate epibionts on the freshwater shrimp Caridina (Decapoda, Atyidae), in particular from the ancient Malili lake system on Sulawesi (Indonesia), were studied. These ciliates belong to the following genera: the suctorian Acineta, and the peritrichs Thuricola, Cothurnia, Vorticella, Opercularia, and Zoothamnium. The ciliates were located on diverse areas of the surface and appendages of the shrimp. Morphological and taxonomical

Kristina Zitzler; Regina Gabilondo

2006-01-01

205

Cytotoxicity assessment of three therapeutic agents, cyclosporin-A, cisplatin and doxorubicin, with the ciliated protozoan Tetrahymena pyriformis  

Microsoft Academic Search

Cyclosporin-A, a drug possessing potent immunosuppressive properties, is used to prevent allograft rejection. Cisplatin and doxorubicin are two of the pharmaceutical drugs most widely used in cancer chemotherapy. In this study, the cytotoxicological impact of these three therapeutic agents was determined using bioassays performed with a unicellular eukaryote, the ciliated protozoan Tetrahymena pyriformis. For this purpose we used the population

Jean-Louis Bonnet; Martine Dusser; Jacques Bohatier; Josée Laffosse

2003-01-01

206

Macrophage and T-Cell Gene Expression in a Model of Early Infection with the Protozoan Leishmania chagasi  

Microsoft Academic Search

Visceral leishmaniasis is a potentially fatal infectious disease caused by the protozoan parasite Leishmania infantum\\/chagasi in the New World, or by L. donovani or L. infantum\\/chagasi in the Old World. Infection leads to a variety of outcomes ranging from asymptomatic infection to active disease, characterized by fevers, cachexia, hepatosplenomegaly and suppressed immune responses. We reasoned that events occurring during the

Nicholas A. Ettinger; Mary E. Wilson

2008-01-01

207

Characterization of cytosine methylated regions and 5-cytosine DNA methyltransferase (Ehmeth) in the protozoan parasite Entamoeba histolytica  

Microsoft Academic Search

The DNA methylation status of the protozoan para- site Entamoeba histolytica was heretofore unknown. In the present study, we developed a new technique, based on the affinity of methylated DNA to 5-methyl- cytosine antibodies, to identify methylated DNA in this parasite. Ribosomal DNA and ribosomal DNA circles were isolated by this method and we con- firmed the validity of our

Ohad Fisher; Rama Siman-Tov; Serge Ankri

2004-01-01

208

Tubulin Biosynthesis in the Developmental Cycle of a Parasitic Protozoan, Leishmania mexicana: Changes during Differentiation of Motile and Nonmotile Stages  

Microsoft Academic Search

Cytodifferentiation in the transmission cycle of the parasitic protozoan Leishmania mexicana amazonensis was studied in vitro. The flagellated motile promastigotes transform into the nonmotile amastigotes in 7 days at 35 degrees C intracellularly in the murine macrophage line J774G8. In medium 199 plus fetal bovine serum, the reverse transformation occurs extracellularly at 27 degrees C in 2 days. Slab gel

Dunne Fong; Kwang-Poo Chang

1981-01-01

209

Structure of a Protozoan Virus from the Human Genitourinary Parasite Trichomonas vaginalis  

PubMed Central

ABSTRACT The flagellated protozoan Trichomonas vaginalis is an obligate human genitourinary parasite and the most frequent cause of sexually transmitted disease worldwide. Most clinical isolates of T. vaginalis are persistently infected with one or more double-stranded RNA (dsRNA) viruses from the genus Trichomonasvirus, family Totiviridae, which appear to influence not only protozoan biology but also human disease. Here we describe the three-dimensional structure of Trichomonas vaginalis virus 1 (TVV1) virions, as determined by electron cryomicroscopy and icosahedral image reconstruction. The structure reveals a T = 1 capsid comprising 120 subunits, 60 in each of two nonequivalent positions, designated A and B, as previously observed for fungal Totiviridae family members. The putative protomer is identified as an asymmetric AB dimer consistent with either decamer or tetramer assembly intermediates. The capsid surface is notable for raised plateaus around the icosahedral 5-fold axes, with canyons connecting the 2- and 3-fold axes. Capsid-spanning channels at the 5-fold axes are unusually wide and may facilitate release of the viral genome, promoting dsRNA-dependent immunoinflammatory responses, as recently shown upon the exposure of human cervicovaginal epithelial cells to either TVV-infected T. vaginalis or purified TVV1 virions. Despite extensive sequence divergence, conservative features of the capsid reveal a helix-rich fold probably derived from an ancestor shared with fungal Totiviridae family members. Also notable are mass spectrometry results assessing the virion proteins as a complement to structure determination, which suggest that translation of the TVV1 RNA-dependent RNA polymerase in fusion with its capsid protein involves ?2, and not +1, ribosomal frameshifting, an uncommonly found mechanism to date.

Parent, Kristin N.; Takagi, Yuko; Cardone, Giovanni; Olson, Norman H.; Ericsson, Maria; Yang, May; Lee, Yujin; Asara, John M.; Fichorova, Raina N.; Baker, Timothy S.; Nibert, Max L.

2013-01-01

210

Protozoan predation, diversifying selection, and the evolution of antigenic diversity in Salmonella  

PubMed Central

Extensive population-level genetic variability at the Salmonella rfb locus, which encodes enzymes responsible for synthesis of the O-antigen polysaccharide, is thought to have arisen through frequency-dependent selection (FDS) by means of exposure of this pathogen to host immune systems. The FDS hypothesis works well for pathogens such as Haemophilus influenzae and Neisseria meningitis, which alter the composition of their O-antigens during the course of bloodborne infections. In contrast, Salmonella remains resident in epithelial cells or macrophages during infection and does not have phase variability in its O-antigen. More importantly, Salmonella shows host–serovar specificity, whereby strains bearing certain O-antigens cause disease primarily in specific hosts; this behavior is inconsistent with FDS providing selection for the origin or maintenance of extensive polymorphism at the rfb locus. Alternatively, selective pressure may originate from the host intestinal environment itself, wherein diversifying selection mediated by protozoan predation allows for the continued existence of Salmonella able to avoid consumption by host-specific protozoa. This selective pressure would result in high population-level diversity at the Salmonella rfb locus without phase variation. We show here that intestinal protozoa recognize antigenically diverse Salmonella with different efficiencies and demonstrate that differences solely in the O-antigen are sufficient to allow for prey discrimination. Combined with observations of the differential distributions of both serotypes of bacterial species and their protozoan predators among environments, our data provides a framework for the evolution of high genetic diversity at the rfb locus and host-specific pathogenicity in Salmonella.

Wildschutte, Hans; Wolfe, David M.; Tamewitz, Aletheia; Lawrence, Jeffrey G.

2004-01-01

211

Generation and analysis of expressed sequence tags from the ciliate protozoan parasite Ichthyophthirius multifiliis  

PubMed Central

Background The ciliate protozoan Ichthyophthirius multifiliis (Ich) is an important parasite of freshwater fish that causes 'white spot disease' leading to significant losses. A genomic resource for large-scale studies of this parasite has been lacking. To study gene expression involved in Ich pathogenesis and virulence, our goal was to generate expressed sequence tags (ESTs) for the development of a powerful microarray platform for the analysis of global gene expression in this species. Here, we initiated a project to sequence and analyze over 10,000 ESTs. Results We sequenced 10,368 EST clones using a normalized cDNA library made from pooled samples of the trophont, tomont, and theront life-cycle stages, and generated 9,769 sequences (94.2% success rate). Post-sequencing processing led to 8,432 high quality sequences. Clustering analysis of these ESTs allowed identification of 4,706 unique sequences containing 976 contigs and 3,730 singletons. These unique sequences represent over two million base pairs (~10% of Plasmodium falciparum genome, a phylogenetically related protozoan). BLASTX searches produced 2,518 significant (E-value < 10-5) hits and further Gene Ontology (GO) analysis annotated 1,008 of these genes. The ESTs were analyzed comparatively against the genomes of the related protozoa Tetrahymena thermophila and P. falciparum, allowing putative identification of additional genes. All the EST sequences were deposited by dbEST in GenBank (GenBank: EG957858–EG966289). Gene discovery and annotations are presented and discussed. Conclusion This set of ESTs represents a significant proportion of the Ich transcriptome, and provides a material basis for the development of microarrays useful for gene expression studies concerning Ich development, pathogenesis, and virulence.

Abernathy, Jason W; Xu, Peng; Li, Ping; Xu, De-Hai; Kucuktas, Huseyin; Klesius, Phillip; Arias, Covadonga; Liu, Zhanjiang

2007-01-01

212

Enrichment of specific protozoan populations during in situ bioremediation of uranium-contaminated groundwater  

PubMed Central

The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uranium-contaminated aquifer located in Rifle, CO, USA, acetate amendments initially promoted the growth of metal-reducing Geobacter species, followed by the growth of sulfate reducers, as observed previously. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater before the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the ameboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a prey–predator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies.

Holmes, Dawn E; Giloteaux, Ludovic; Williams, Kenneth H; Wrighton, Kelly C; Wilkins, Michael J; Thompson, Courtney A; Roper, Thomas J; Long, Philip E; Lovley, Derek R

2013-01-01

213

Pelagicoccus croceus sp. nov., a novel marine member of the family Puniceicoccaceae within the phylum 'Verrucomicrobia' isolated from seagrass.  

PubMed

An obligately aerobic, spherical, non-motile, pale-yellow pigmented bacterium was isolated from a piece of leaf of seagrass, Enhalus acoroides (L.f.) Royle, grown in Okinawa, Japan and was subjected to a polyphasic taxonomic study. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the novel isolate N5FB36-5(T) shared approximately 96-98 % sequence similarity with the species of the genus Pelagicoccus of the family Puniceicoccaceae within the phylum 'Verrucomicrobia'. The DNA-DNA relatedness values of strain N5FB36-5(T) with Pelagicoccus mobilis 02PA-Ca-133(T) and Pelagicoccus albus YM14-201(T) were below 70 %, which is accepted as the phylogenetic definition of a novel species. beta-Lactam antibiotic susceptibility test and amino acid analysis of the cell wall hydrolysates indicated the absence of muramic acid and diaminopimelic acid in the cell walls, which suggested that this strain lacks an ordinary Gram-negative type of peptidoglycan in the cell wall. The DNA G+C content of strain N5FB36-5(T) was 51.6 mol%; MK-7 was the major menaquinone; and the presence of C(16 : 0), C(16 : 1)omega7c and anteiso-C(15 : 0) as the major cellular fatty acids supported the identification of the novel isolate as a member of the genus Pelagicoccus. On the basis of polyphasic taxonomic data, it was concluded that this strain should be classified as a novel species of the genus Pelagicoccus, for which the name Pelagicoccus croceus sp. nov. is proposed. The type strain is N5FB36-5(T) (=MBIC08283(T)=KCTC [corrected] 12903(T)). PMID:18048742

Yoon, Jaewoo; Oku, Naoya; Matsuda, Satoru; Kasai, Hiroaki; Yokota, Akira

2007-12-01

214

Screening of antiangiogenic potential of twenty two marine invertebrate extracts of phylum Mollusca from South East Coast of India  

PubMed Central

Objective To evaluate the antiangiogenic potential of twenty two marine invertebrate species of Phylum Mollusca from south east coast of India. Methods Live specimens of molluscan species were collected and their methanolic extracts were evaluated for preliminary antiangiogenic activity using the in ovo chick chorio-allantoic membrane assay. The extracts were further evaluated for in vivo antiangiogenic activity using chemical cautery induced corneal neovascularization assay in rats and oxygen induced retinopathy assay in rat pups. Results In the chick chorio-allantoic membrane assay, four methanolic extracts of marine molluscan species viz. Meretrix meretrix, Meretrix casta, Telescopium telescopium and Bursa crumena methanolic extracts exhibited noticeable antiangiogenic activity at the tested concentration of 200 µg whereby they significantly inhibited the VEGF induced proliferation of new blood vessels. Among these four extracts, the methanolic extract of Meretrix casta exhibited relatively higher degree of antiangiogenic activity with an inhibitiory percentage (64.63%) of the VEGF induced neovascularization followed by the methanolic extracts of Telescopium telescopium (62.02%), Bursa crumena (60.48%) and Meretrix meretrix (47.01%). These four methanolic extracts were further evaluated for in vivo antiangiogenic activity whereby the methanolic extract of Telescopium telescopium exhibited most noticeable inhibition (42.58%) of the corneal neovascularization in rats in comparison to the sham treated group, and also exhibited most noticeable inhibition (31.31%) of the oxygen induced retinal neovascularization in rat pups in comparison to the hyperoxia group that was observed for considerable retinal neovascularization. Conclusions The significant antiangiogenic activity evinced by the extract of Telescopium telescopium merits further investigation for ocular neovascular diseases.

Gupta, Pankaj; Arumugam, Muthuvel; Azad, Raj Vardhan; Saxena, Rohit; Ghose, Supriyo; Biswas, Nihar Ranjan; Velpandian, Thirumurthy

2014-01-01

215

Molecular identification of Sarcocystis hominis in native cattle of central Iran: A case report.  

PubMed

Sarcocystis spp. are two-host protozoan parasites belonging to the phylum Apicomplexa. Among different known species of Sarcocystis in cattle, only Sarcocystis hominis is important from the public health viewpoint, because of its zoonotic characteristics. This study presents the first molecular identification of S. hominis in native cattle in central Iran. A sample of diaphragm muscle from a 6-year-old native cow slaughtered at Yazd Slaughterhouse, Yazd, central Iran, was collected in May 2013. DNA extraction was performed, using the salting-out method. DNA purification and precipitation were performed consecutively. The amplicon and digestion results were analyzed using agarose gel electrophoresis. A PCR product with 926 bp in length was obtained after amplification, and 376 bp and 550 bp in length after digestion that identified S. hominis. To the best of our knowledge, this study is the first of its kind to be reported from Iran. PMID:24862059

Hajimohammadi, B; Eslami, G; Oryan, A; Zohourtabar, A; Pourmirzaei Tafti, H; Moghaddam Ahmadi, M

2014-03-01

216

Cytoskeleton assembly in Toxoplasma gondii cell division  

PubMed Central

Cell division across members of the protozoan parasite phylum Apicomplexa displays a surprising diversity between different species as well as between different life stages of the same parasite. In most cases, infection of a host cell by a single parasite results in the formation of a polyploid cell from which individual daughters bud in a process dependent on a final round of mitosis. Unlike other apicomplexans, Toxoplasma gondii divides by a binary process consisting of internal budding that results in only two daughter cells per round of division. Since T. gondii is experimentally accessible and displays the simplest division mode, it has manifested itself as a model for apicomplexan daughter formation. Here we review newly emerging insights in the prominent role that assembly of the cortical cytoskeletal scaffold plays in the process of daughter parasite formation.

Anderson-White, Brooke; Beck, Josh R.; Chen, Chun-Ti; Meissner, Markus; Bradley, Peter J.; Gubbels, Marc-Jan

2014-01-01

217

Pyrinomonas methylaliphatogenes gen. nov., sp. nov., a novel group 4 thermophilic member of the phylum Acidobacteria from geothermal soils.  

PubMed

An aerobic, thermophilic, moderately acidophilic non-spore-forming bacterium, strain K22(T), was isolated from geothermally heated soil at Mount Ngauruhoe, New Zealand. On the basis of 16S rRNA gene sequence similarity, K22(T) was shown to belong to subdivision 4 of the phylum Acidobacteria and to be most closely related to 'Candidatus Chloracidobacterium thermophilum' (86?%) and Blastocatella fastidiosa (86?%). Cells stained Gram-negative and were catalase and oxidase-positive. The major fatty acids detected were iso-C15?:?0, iso-C17?:?0, iso-C19?:?0 and iso-C21?:?0 when standard lipid extraction protocols were employed. Analysis of the total cell lipid acid hydrolysate also detected membrane-spanning and ether lipids, which made up approximately 40?% of the total membrane composition. These lipids included dicarboxylic (iso-diabolic) acid and the glyceryl ether of alkyl analogues of iso-C15?:?0 and iso-diabolic acid. The G+C content of the genomic DNA was 59.6 mol% and the primary respiratory quinone was MK-8. Strain K22(T) grew at 50-69 °C with an optimum temperature of 65 °C and at pH 4.1-7.8 with an optimum growth pH of 6.5. NaCl tolerance was up to 1?% (w/v). Cells displayed a chemoheterotrophic and obligately aerobic metabolism. Cells grew on nutrient broth, alginate, arabinose, Casamino acids, glucose, lactate, formate, mannose, sodium alginate, peptone, sucrose, tryptone, xanthan, xylan, xylose and yeast extract. Nitrogen sources included nitrate, ammonium, urea, yeast extract and Casamino acids, but not dinitrogen gas. The distinct phylogenetic position and the phenotypic characteristics separate strain K22(T) from all other members of the class Acidobacteria and indicate that it represents a novel species and genus, for which the name Pyrinomonas methylaliphatogenes gen. nov., sp. nov. is proposed. The type strain of the type species is K22(T) (?=?DSM 25857(T)?=?ICMP 18710(T)). PMID:24048862

Crowe, M A; Power, J F; Morgan, X C; Dunfield, P F; Lagutin, K; Rijpstra, W I C; Rijpstra, I C; Vyssotski, G N S; Sinninghe Damste, J S; Houghton, K M; Ryan, J L J; Stott, M B

2014-01-01

218

The neogregarine protozoan Farinocystis sp. reduces longevity and fecundity in the West Indian sweet potato weevil, Euscepes postfasciatus (Fairmaire).  

PubMed

The number of West Indian sweet potato weevils, Euscepes postfasciatus, being mass-reared in a facility for use in sterile insect technique (SIT) eradication programs has undergone a drastic reduction. A neogregarine protozoan pathogen Farinocystis sp. (an undescribed species) was detected in vivo in the mass-reared E. postfasciatus. We investigated the effects of this disease on the longevity and fecundity of host weevils and the incubation time of the disease in the host body under mass-rearing conditions. Our results demonstrated that infection by this Farinocystis sp. decreased both longevity and fecundity in E. postfasciatus. In particular, the pathogen severely limited the production of progeny by infected females compared to healthy females. Therefore, we consider this protozoan infection to be the major cause of the decreased E. postfasciatus production in the mass-rearing facility. PMID:20736016

Kumano, Norikuni; Iwata, Noriko; Kuriwada, Takashi; Shiromoto, Keiko; Haraguchi, Dai; Yasunaga-Aoki, Chisa; Kohama, Tsuguo

2010-11-01

219

Virulence of a Legionella anisa strain associated with Pontiac fever: an evaluation using protozoan, cell culture, and guinea pig models.  

PubMed Central

Legionella anisa and the amoeba Hartmannella vermiformis were isolated from an indoor fountain implicated as the infectious reservoir in an outbreak of Pontiac fever. We evaluated the ability of this strain of L. anisa to multiply in cultures of an amoeba (H. vermiformis), a ciliated protozoan (Tetrahymena pyriformis), and human mononuclear cells and to infect guinea pigs. These bacteria multiplied in the culture of H. vermiformis but failed to infect guinea pigs or the cultures of T. pyriformis and human mononuclear cells. These findings suggest that some Legionella spp. may multiply only in specific protozoan hosts. The inability of this strain of L. anisa to multiply in human phagocytic cells may be related to the development of Pontiac fever rather than pneumonic legionellosis in exposed individuals. Further studies are necessary to determine whether the ability of legionellae to infect certain host cells can be correlated to differences in human disease.

Fields, B S; Barbaree, J M; Sanden, G N; Morrill, W E

1990-01-01

220

Identification and characterization of a type III Trichomonas vaginalis virus in the protozoan pathogen Trichomonas vaginalis.  

PubMed

A type III Trichomonas vaginalis virus, which may be involved in transcriptional regulation of the major surface protein gene P270 of the protozoan pathogen Trichomonas vaginalis, was purified and characterized in the present study. The complete 4844-base-pair complementary DNA sequence of the viral genome reveals overlapping cap and pol genes with a putative ribosomal frame-shifting signal within the overlap region. The type III virus is related more closely to the type II virus than to the type I virus in the sequence of its ribosomal frameshift signal and in its capsid protein. Phylogenetic analysis revealed that these viruses could be grouped in the same clade as a genus distantly related to other genera in the family Totiviridae. Virus-induced P270 gene expression was only evident in Trichomonas vaginalis cells infected with either a type II or type III virus, but not with a type I virus. These findings suggest that transcription of the P270 gene is likely regulated by viral factors common to type II and type III viruses and thus provides important information for future investigation of virus-host interactions. PMID:21110050

Bessarab, Irina N; Nakajima, Rui; Liu, Hsing-Wei; Tai, Jung-Hsiang

2011-02-01

221

The ability of the rumen ciliate protozoan Diploplastron affine to digest and ferment starch.  

PubMed

The ciliate Diploplastron affine is known as a common species of the rumen fauna in cattle and sheep. This protozoon is able to digest cellulose, whereas its amylolytic activity is not well known. The objective of the reported studies was to examine the ability of D. affine to digest starch and to use this polysaccharide to cover the requirement for energy. The enzymatic studies showed that the protozoal cell extract degraded starch to reducing products with the rate being equivalent to 2.4?±?0.47 ?mol/L glucose per mg protein per min. Maltose, maltotriose and a small quantity of glucose were the end products of starch degradation. The degradation rate of maltose was only 0.05 ?mol/L glucose per mg protein per min. Two peaks in ?-amylase and a single peak in maltase activity were found following molecular filtration of ciliate cell extract, whereas three starch-degrading enzymes were identified by a zymographic technique. Incubation of the bacteria-free ciliates with starch in the presence of antibiotics resulted in a release of volatile fatty acids with the net rate of 25 pmol per protozoan per h. Acetic acid followed by butyric acid was the main product of starch fermentation. The results confirmed the ability of D. affine to utilize starch in energy-yielding processes. PMID:22528316

Wereszka, K; Micha?owski, T

2012-07-01

222

The meaning of death: evolution and ecology of apoptosis in protozoan parasites.  

PubMed

The discovery that an apoptosis-like, programmed cell death (PCD) occurs in a broad range of protozoan parasites offers novel therapeutic tools to treat some of the most serious infectious diseases of humans, companion animals, wildlife, and livestock. Whilst apoptosis is an essential part of normal development, maintenance, and defence in multicellular organisms, its occurrence in unicellular parasites appears counter-intuitive and has proved highly controversial: according to the Darwinian notion of "survival of the fittest", parasites are expected to evolve strategies to maximise their proliferation, not death. The prevailing, and untested, opinion in the literature is that parasites employ apoptosis to "altruistically" self-regulate the intensity of infection in the host/vector. However, evolutionary theory tells us that at most, this can only be part of the explanation, and other non-mutually exclusive hypotheses must also be tested. Here, we explain the evolutionary concepts that can explain apoptosis in unicellular parasites, highlight the key questions, and outline the approaches required to resolve the controversy over whether parasites "commit suicide". We highlight the need for integration of proximate and functional approaches into an evolutionary framework to understand apoptosis in unicellular parasites. Understanding how, when, and why parasites employ apoptosis is central to targeting this process with interventions that are sustainable in the face of parasite evolution. PMID:22174671

Reece, Sarah E; Pollitt, Laura C; Colegrave, Nick; Gardner, Andy

2011-12-01

223

Parameters controlling the rate of gene targeting frequency in the protozoan parasite Leishmania.  

PubMed Central

In this study we investigated the role of several parameters governing the efficiency of gene targeting mediated by homologous recombination in the protozoan parasite Leishmania. We evaluated the relative targeting frequencies of different replacement vectors designed to target several sequences within the parasite genome. We found that a decrease in the length of homologous sequences <1 kb on one arm of the vector linearly influences the targeting frequency. No homologous recombination was detected, however, when the flanking homologous regions were <180 bp. A requirement for a very high degree of homology between donor and target sequences was found necessary for efficient gene targeting in Leishmania , as targeted recombination was strongly affected by base pair mismatches. Targeting frequency increased proportionally with copy number of the target only when the target was part of a linear amplicon, but remained unchanged when it was present on circles. Different chromosomal locations were found to be targeted with significantly variable levels of efficiency. Finally, different strains of the same species showed differences in gene targeting frequency. Overall, gene targeting mediated by homologous recombination in Leishmania shares similarities to both the yeast and the mammalian recombination systems.

Papadopoulou, B; Dumas, C

1997-01-01

224

Seroprevalence rates of antibodies against Leishmania infantum and other protozoan and rickettsial parasites in dogs.  

PubMed

Canine visceral leishmaniasis (CVL) is caused by the protozoan Leishmania infantum, which infects dogs and humans in many regions of Brazil. The present study involved an indirect fluorescent antibody test (IFAT) to analyze L. infantum, Ehrlichia spp., Babesia canis, Toxoplasma gondii and Neospora caninum infection rates in serum samples from 93 dogs in a rural settlement in Ilha Solteira, SP, Brazil. The seroprevalence rates of anti-L. infantum, anti-Ehrlichia, anti-B. canis, anti-T. gondii and anti-N. caninum antibodies were 37.6%, 75.3%, 72%, 47.3% and 6.4%, respectively. In addition to IFAT, direct microscopic examination of popliteal lymph node aspirates revealed 26.9% of CVL positive dogs. Serological tests revealed that 17.2% of the dogs were seropositive for a single parasite, 29% for two parasites, 33% for three, 16.1% for four, and 1.1% for five parasites, while 3.2% were seronegative for five parasites. The presence of antibodies against these parasites in serum samples from dogs confirmed their exposure to these parasites in this rural area. Because of the potential zoonotic risk of these diseases, mainly leishmaniasis, ehrlichiosis and toxoplasmosis, special attention should focus on programs for the improvement of diagnostic assays and control measures against these parasites. PMID:24252965

Paulan, Silvana de Cássia; Lins, Aline Gouveia de Souza; Tenório, Michely da Silva; Silva, Diogo Tiago da; Pena, Hilda Fátima de Jesus; Machado, Rosangela Zacarias; Gennari, Solange Maria; Buzetti, Wilma Aparecida Starke

2013-01-01

225

Molecular detection of protozoan parasites infecting Apis mellifera colonies in Japan.  

PubMed

The role of protozoan parasites in honey bee health and distribution in the world is not well understood. Therefore, we carried out a molecular survey for the presence of Crithidia mellificae and Apicystis bombi in the colonies of both non-native Apis mellifera and native Apis cerana japonica in Japan. We found that A.?mellifera, but not A.?c.?japonica, colonies are parasitized with C.?mellificae and A.?bombi. Their absence in A.?c.?japonica colonies indicates that A.?mellifera is their native host. Nevertheless, the prevalence in A.?mellifera colonies is low compared with other pathogens such as viruses and Nosema microsporidia. Japanese C.?mellificae isolates share well-conserved nuclear-encoded gene sequences with Swiss and US isolates. We have found two Japanese haplotypes (A and B) with two nucleotide differences in the kinetoplast-encoded cytochrome b sequence. The haplotype A is identical to Swiss isolate. These results demonstrate that C.?mellificae and A.?bombi distribute in Asia, Oceania, Europe, and South and North Americas. PMID:23757133

Morimoto, Tomomi; Kojima, Yuriko; Yoshiyama, Mikio; Kimura, Kiyoshi; Yang, Bu; Peng, Guangda; Kadowaki, Tatsuhiko

2013-02-01

226

Protozoan ALKBH8 Oxygenases Display both DNA Repair and tRNA Modification Activities  

PubMed Central

The ALKBH family of Fe(II) and 2-oxoglutarate dependent oxygenases comprises enzymes that display sequence homology to AlkB from E. coli, a DNA repair enzyme that uses an oxidative mechanism to dealkylate methyl and etheno adducts on the nucleobases. Humans have nine different ALKBH proteins, ALKBH1–8 and FTO. Mammalian and plant ALKBH8 are tRNA hydroxylases targeting 5-methoxycarbonylmethyl-modified uridine (mcm5U) at the wobble position of tRNAGly(UCC). In contrast, the genomes of some bacteria encode a protein with strong sequence homology to ALKBH8, and robust DNA repair activity was previously demonstrated for one such protein. To further explore this apparent functional duality of the ALKBH8 proteins, we have here enzymatically characterized a panel of such proteins, originating from bacteria, protozoa and mimivirus. All the enzymes showed DNA repair activity in vitro, but, interestingly, two protozoan ALKBH8s also catalyzed wobble uridine modification of tRNA, thus displaying a dual in vitro activity. Also, we found the modification status of tRNAGly(UCC) to be unaltered in an ALKBH8 deficient mutant of Agrobacterium tumefaciens, indicating that bacterial ALKBH8s have a function different from that of their eukaryotic counterparts. The present study provides new insights on the function and evolution of the ALKBH8 family of proteins.

Zdzalik, Daria; Vagb?, Cathrine B.; Kirpekar, Finn; Davydova, Erna; Puscian, Alicja; Maciejewska, Agnieszka M.; Krokan, Hans E.; Klungland, Arne; Tudek, Barbara; van den Born, Erwin; Falnes, Pal ?.

2014-01-01

227

Prevalence of protozoan infections in darkling beetles from poultry houses in North Carolina.  

PubMed

A study was conducted from November 1990 to February 1992 on the prevalence of protozoan infections in the darkling beetle, Alphitobius diaperinus (Coleoptera, Tenebrionidae), from turkey and broiler houses in the southeastern, northeastern, and central Piedmont regions of North Carolina. Darkling beetles were commonly infected with the eugregarine Gregarina alphitobii, an undescribed species of Gregarina (Eugregarinorida, Gregarinidae) and the neogregarine Farinocystis tribolii (Neogregarinorida, Lipotrophidae). Both eugregarine and neogregarine parasites were present throughout the sampling period. A decreasing trend in percentage infection by eugregarines in darkling beetles from broiler houses was observed through time while percentage infection in turkey houses showed a variable trend. Percentage neogregarine infection exhibited a variable trend with a significant difference in the overall rate of infection in the two types of production houses. Neogregarine infection was higher in the broiler houses than in the turkey houses. Both adult and larval stages of the beetle were infected with the gregarines with higher levels of infection observed in the larval stages. Mixed infections with both types of gregarines were highest in the smallest larvae. PMID:8021524

Apuya, L C; Stringham, S M; Arends, J J; Brooks, W M

1994-05-01

228

Genetic variation in resistance, but not tolerance, to a protozoan parasite in the monarch butterfly  

PubMed Central

Natural selection should strongly favour hosts that can protect themselves against parasites. Most studies on animals so far have focused on resistance, a series of mechanisms through which hosts prevent infection, reduce parasite growth or clear infection. However, animals may instead evolve tolerance, a defence mechanism by which hosts do not reduce parasite infection or growth, but instead alleviate the negative fitness consequences of such infection and growth. Here, we studied genetic variation in resistance and tolerance in the monarch butterfly (Danaus plexippus) to its naturally occurring protozoan parasite, Ophryocystis elektroscirrha. We exposed 560 monarch larvae of 19 different family lines to one of five different parasite inoculation doses (0, 1, 5, 10 and 100 infective spores) to create a range of parasite loads in infected butterflies. We then used two proxies of host fitness (adult lifespan and body mass) to quantify: (i) qualitative resistance (the ability to prevent infection; also known as avoidance or anti-infection resistance); (ii) quantitative resistance (the ability to limit parasite growth upon infection; also known as control or anti-growth resistance); and (iii) tolerance (the ability to maintain fitness with increasing parasite infection intensity). We found significant differences among host families in qualitative and quantitative resistance, indicating genetic variation in resistance. However, we found no genetic variation in tolerance. This may indicate that all butterflies in our studied population have evolved maximum tolerance, as predicted by some theoretical models.

Lefevre, Thierry; Williams, Amanda Jo; de Roode, Jacobus C.

2011-01-01

229

Development of an Aeromonas hydrophila? infection model using the protozoan Tetrahymena thermophila.  

PubMed

Aeromonas hydrophila is a motile bacterium present in numerous freshwater habitats worldwide and is frequently the cause of infections in fish and numerous terrestrial vertebrates including humans. Because A. hydrophila is also a component of the normal intestinal flora of healthy fish, virulence mechanisms are not well understood. Considering that fish models used for the examination of A. hydrophila genes associated with virulence have not been well defined, we established an infection model using the free-living, ciliate protozoa Tetrahymena thermophila. The expression of A. hydrophila virulence genes following infection of T. thermophila was assessed by reverse transcription-PCR and demonstrated that the aerolysin (aerA) and Ahe2 serine protease (ahe2) genes (not present in the avirulent A. hydrophila NJ-4 strain) in the virulent J-1 strain were upregulated 4-h postinfection. Furthermore, the presence of intact A. hydrophila J-1 within T. thermophila suggested that these bacteria could interfere with phagocytosis, resulting in the death of the infected protozoan 48-h postinfection. Conversely, A. hydrophila NJ-4-infected T. thermophila survived the infection. This study established a novel T. thermophila infection model that will provide a novel means of examining virulence mechanisms of A. hydrophila. PMID:21204941

Li, Jing; Zhang, Xiao-Lu; Liu, Yong-Jie; Lu, Cheng-Ping

2011-03-01

230

Bax function in the absence of mitochondria in the primitive protozoan Giardia lamblia.  

PubMed

Bax-induced permeabilization of the mitochondrial outer membrane and release of cytochrome c are key events in apoptosis. Although Bax can compromise mitochondria in primitive unicellular organisms that lack a classical apoptotic machinery, it is still unclear if Bax alone is sufficient for this, or whether additional mitochondrial components are required. The protozoan parasite Giardia lamblia is one of the earliest branching eukaryotes and harbors highly degenerated mitochondrial remnant organelles (mitosomes) that lack a genome. Here we tested whether human Bax expressed in Giardia can be used to ablate mitosomes. We demonstrate that these organelles are neither targeted, nor compromised, by Bax. However, specialized compartments of the regulated secretory pathway are completely ablated by Bax. As a consequence, maturing cyst wall proteins that are sorted into these organelles are released into the cytoplasm, causing a developmental arrest and cell death. Interestingly, this ectopic cargo release is dependent on the carboxy-terminal 22 amino acids of Bax, and can be prevented by the Bax-inhibiting peptide Ku70. A C-terminally truncated Bax variant still localizes to secretory organelles, but is unable to permeabilize these membranes, uncoupling membrane targeting and cargo release. Even though mitosomes are too diverged to be recognized by Bax, off-target membrane permeabilization appears to be conserved and leads to cell death completely independently of mitochondria. PMID:17534438

Hehl, Adrian B; Regos, Attila; Schraner, Elisabeth; Schneider, André

2007-01-01

231

The first suicides: a legacy inherited by parasitic protozoans from prokaryote ancestors.  

PubMed

It is more than 25 years since the first report that a protozoan parasite could die by a process resulting in a morphological phenotype akin to apoptosis. Since then these phenotypes have been observed in many unicellular parasites, including trypanosomatids and apicomplexans, and experimental evidence concerning the molecular pathways that are involved is growing. These observations support the view that this form of programmed cell death is an ancient one that predates the evolution of multicellularity. Here we review various hypotheses that attempt to explain the origin of apoptosis, and look for support for these hypotheses amongst the parasitic protists as, with the exception of yeast, most of the work on death mechanisms in unicellular organisms has focussed on them. We examine the role that addiction modules may have played in the original eukaryote cell and the part played by mitochondria in the execution of present day cells, looking for examples from Leishmania spp. Trypanosoma spp. and Plasmodium spp. In addition, the expanding knowledge of proteases, nucleases and other molecules acting in protist execution pathways has enabled comparisons to be made with extant Archaea and bacteria and with biochemical pathways that evolved in metazoans. These comparisons lend support to the original sin hypothesis but also suggest that present-day death pathways may have had multifaceted beginnings. PMID:23597031

Taylor-Brown, Emilie; Hurd, Hilary

2013-04-18

232

Inferring host range dynamics from comparative data: the protozoan parasites of new world monkeys.  

PubMed

Abstract Uncovering the ecological determinants of parasite host range is a central goal of comparative parasitology and infectious disease ecology. But while parasites are often distributed nonrandomly across the host phylogeny, such patterns are difficult to interpret without a genealogy for the parasite samples and without knowing what sorts of ecological dynamics might lead to what sorts of nonrandomness. We investigated inferences from comparative data, using presence/absence records from protozoan parasites of the New World monkeys. We first demonstrate several distinct types of phylogenetic signal in these data, showing, for example, that parasite species are clustered on the host tree and that closely related host species harbor similar numbers of parasite species. We then show that all of these patterns can be generated by a single, simple dynamical model, in which parasite host range changes more rapidly than host speciation/extinction and parasites preferentially colonize uninfected host species that are closely related to their existing hosts. Fitting this model to data, we then estimate its parameters. Finally, we caution that quite different ecological processes can lead to similar signatures but show how phylogenetic variation in host susceptibility can be distinguished from a tendency for parasites to colonize closely related hosts. Our new process-based analyses, which estimate meaningful parameters, should be useful for inferring the determinants of parasite host range and transmission success. PMID:24921601

Waxman, David; Weinert, Lucy A; Welch, John J

2014-07-01

233

Waterborne transmission of protozoan parasites: review of worldwide outbreaks - an update 2004-2010.  

PubMed

The present update gives a comprehensive review of worldwide waterborne parasitic protozoan outbreaks that occurred and were published globally between January 2004 and December 2010. At least one hundred and ninety-nine outbreaks of human diseases due to the waterborne transmission of parasitic protozoa occurred and were reported during the time period from 2004 to 2010. 46.7% of the documented outbreaks occurred on the Australian continent, 30.6% in North America and 16.5% in Europe. Cryptosporidium spp. was the etiological agent in 60.3% (120) of the outbreaks, Giardia lamblia in 35.2% (70) and other protozoa in 4.5% (9). Four outbreaks (2%) were caused by Toxoplasma gondii, three (1.5%) by Cyclospora cayetanensis. In two outbreaks (1%) Acanthamoeba spp. was identified as the causative agent. In one outbreak, G. lamblia (in 17.6% of stool samples) and Cryptosporidium parvum (in 2.7% of stool samples) as well as Entamoeba histolytica (in 9.4% of stool samples) and Blastocystis hominis (in 8.1% of stool samples) were detected. In those countries that are likely affected most a lack of surveillance systems is noticeable. However, countries that established surveillance systems did not establish an international standardization of reporting systems. PMID:22048017

Baldursson, Selma; Karanis, Panagiotis

2011-12-15

234

The first suicides: a legacy inherited by parasitic protozoans from prokaryote ancestors  

PubMed Central

It is more than 25 years since the first report that a protozoan parasite could die by a process resulting in a morphological phenotype akin to apoptosis. Since then these phenotypes have been observed in many unicellular parasites, including trypanosomatids and apicomplexans, and experimental evidence concerning the molecular pathways that are involved is growing. These observations support the view that this form of programmed cell death is an ancient one that predates the evolution of multicellularity. Here we review various hypotheses that attempt to explain the origin of apoptosis, and look for support for these hypotheses amongst the parasitic protists as, with the exception of yeast, most of the work on death mechanisms in unicellular organisms has focussed on them. We examine the role that addiction modules may have played in the original eukaryote cell and the part played by mitochondria in the execution of present day cells, looking for examples from Leishmania spp. Trypanosoma spp. and Plasmodium spp. In addition, the expanding knowledge of proteases, nucleases and other molecules acting in protist execution pathways has enabled comparisons to be made with extant Archaea and bacteria and with biochemical pathways that evolved in metazoans. These comparisons lend support to the original sin hypothesis but also suggest that present-day death pathways may have had multifaceted beginnings.

2013-01-01

235

Metazoan-protozoan parasite co-infections and host body weight in St Kilda Soay sheep.  

PubMed

For hundreds of years, the unmanaged Soay sheep population on St Kilda has survived despite enduring presumably deleterious co-infections of helminth, protozoan and arthropod parasites and intermittent periods of starvation. Important parasite taxa in young Soay sheep are strongyles (Trichostrongylus axei, Trichostrongylus vitrinus and Teladorsagia circumcincta), coccidia (11 Eimeria species) and keds (Melophagus ovinus) and in older animals, Teladorsagia circumcincta. In this research, associations between the intensity of different parasite taxa were investigated. Secondly, the intensities of different parasite taxa were tested for associations with variation in host weight, which is itself a determinant of over-winter survival in the host population. In lambs, the intensity of strongyle eggs was positively correlated with that of Nematodirus spp. eggs, while in yearlings and adults strongyle eggs and coccidia oocysts were positively correlated. In lambs and yearlings, of the parasite taxa tested, only strongyle eggs were significantly and negatively associated with host weight. However, in adult hosts, strongyles and coccidia were independently and negatively associated with host weight. These results are consistent with the idea that strongyles and coccidia are exerting independent selection on Soay sheep. PMID:18215336

Craig, B H; Tempest, L J; Pilkington, J G; Pemberton, J M

2008-04-01

236

Nitazoxanide in the treatment of patients with intestinal protozoan and helminthic infections: a report on 546 patients in egypt  

Microsoft Academic Search

Nitazoxanide, a new broad-spectrum antiprotozoal\\/anthelmintic drug, was tested in 546 patients with single or multiple intestinal protozoan and helminthic infections. After inclusion in the study, patients at least 12 years of age were instructed to take one nitazoxanide 500-mg table every 12 hours for 3 consecutive days. The guardians of the children aged 4 to 11 years were instructed to

Himly Abaza; Abdul Rahman El-Zayadi; Samir M. Kabil; Hassan Rizk

1998-01-01

237

In vitro analysis of the TAT protein transduction domain as a drug delivery vehicle in protozoan parasites  

Microsoft Academic Search

The present study was undertaken to analyse the capability of HIV-1 derived TAT protein transduction domain (PTD) fused with Green Fluorescent Protein (TAT-GFP) as a delivery vehicle into a range of protozoan parasites. Successful transduction of native purified TAT-GFP was observed by fluorescent microscopy in Cryptosporidium parvum, Giardia duodenalis, and Neospora caninum. The ability to transduce peptides and other cargo

Stephanie Hui Chin Lee; Ryan Jefferies; Paul Watt; Richard Hopkins; Frank Sotzik; Simon Reid; Anthony Armson; Annika Boxell; Una Ryan

2008-01-01

238

Detection and localization of a putative cyclic-GMP-activated channel protein in the protozoan ciliate Stentor coeruleus  

Microsoft Academic Search

Summary.  Immunoblotting and immunocytochemical assays were employed to identify and localize a channel protein activated by cyclic\\u000a GMP (cGMP) in the protozoan ciliate Stentor coeruleus. Analysis of whole-cell homogenate with antibodies raised against the ?-subunit of the cGMP-activated channel protein from\\u000a bovine rod outer segments and against cGMP revealed four major protein bands with molecular masses of 40 kDa, 63 kDa,

M. Walerczyk; H. Fabczak; S. Fabczak

2006-01-01

239

Lectin from the Manila Clam Ruditapes philippinarum Is Induced upon Infection with the Protozoan Parasite Perkinsus olseni  

Microsoft Academic Search

Glycan-binding proteins (lectins) are widely expressed in many invertebrates, although the biosynthesis and functions of the lectins are not well understood. Here we report that Manila clam (Ruditapes philippinarum) synthesizes a lectin termed Manila clam lectin (MCL) upon infection with the protozoan parasite Perkinsus olseni. MCL is synthesized in hemocytes as a 74-kDa precursor and secreted into hemolymph where it

Young Mee Kim; Kyung-Il Park; Kwang-Sik Choi; Richard A. Alvarez; Richard D. Cummings; Moonjae Cho

2006-01-01

240

The major surface-metalloprotease of the parasitic protozoan, Leishmania, protects against antimicrobial peptide-induced apoptotic killing  

Microsoft Academic Search

Summary Human infection by the vector-borne protozoan Leishmania is responsible for substantial worldwide morbidity and mortality. The surface-metalloprotease (leishmanolysin) of Leishmania is a virulence factor which contributes to a variety of functions including evasion of complement-mediated parasite-killing and host intramacrophage survival. We tested the hypoth- esis that leishmanolysin serves to protect parasites from the cytolytic effects of various antimicrobial peptides

Manjusha M. Kulkarni; W. Robert McMaster; Elzbieta Kamysz; Wojciech Kamysz; David M. Engman; Bradford S. McGwire

2006-01-01

241

[Occurrence of the flagellated protozoan, Cryptobia helicis Leidy, 1846 (Kinetoplasta: Bodonea: Cryptobiidae) in the garden snail, Helix aspersa].  

PubMed

In this survey, the prevalence and cytological features of the flagellated protozoan, Cryptobia helicis living in the bursa copulatrix of the garden snail, Helix aspersa Müller 1774 found in the vicinity of Izmir, Turkey was investigated. The prevalence of Cryptobia helicis in garden snails collected in the spring of 2005 was found to be 68.65%. This study is the first record of the occurrence of Cryptobia helicis in the garden snail Helix aspersa found in Turkey. PMID:18351561

Göçmen, Bayram; Gürelli, Gözde

2008-01-01

242

Occurrence, removal and accumulation in sludge of protozoan cysts and helminth eggs in a full-scale anaerobic pond in Burkina Faso.  

PubMed

The present paper investigates the occurrence, removal, and accumulation of protozoan cysts and helminth eggs in a large anaerobic pond treating municipal wastewater of Ouagadougou (Burkina Faso). With a hydraulic retention time of 6.5 days, the anaerobic pond achieved 100% removal of helminth eggs and protozoan cysts most of the time, except during the hot period. The average residual concentrations of helminth eggs and protozoan cysts in the effluent were respectively 0.45 eggs/L (minimum 0 and maximum 3), and 5.4 cysts/L (minimum 0 and maximum 26). Protozoan cysts accumulation in sludge averaged 1,613 cysts/g total solids. Ancylostoma duodenale, Ascaris lumbricoides and Hymenolepis nana were the main helminth species found in the sludge. After 7 years of operation, the sludge in the pond still contained a high level of viable helminth eggs evaluated at 42%. PMID:23128639

Konaté, Yacouba; Maiga, Amadou Hama; Basset, Didier; Picot, Bernadette; Casellas, Claude

2013-01-01

243

Genome analysis of Chitinivibrio alkaliphilus gen. nov., sp. nov., a novel extremely haloalkaliphilic anaerobic chitinolytic bacterium from the candidate phylum Termite Group 3.  

PubMed

Anaerobic enrichments from hypersaline soda lakes with chitin as substrate yielded five closely related anaerobic haloalkaliphilic isolates growing on insoluble chitin by fermentation at pH?10 and salinities up to 3.5?M. The chitinolytic activity was exclusively cell associated. To better understand the biology and evolutionary history of this novel bacterial lineage, the genome of the type strain ACht1 was sequenced. Analysis of the 2.6?Mb draft genome revealed enzymes of chitin-degradation pathways, including secreted cell-bound chitinases. The reconstructed central metabolism revealed pathways enabling the fermentation of polysaccharides, while it lacks the genes needed for aerobic or anaerobic respiration. The Rnf-type complex, oxaloacetate decarboxylase and sodium-transporting V-type adenosine triphosphatase were identified among putative membrane-bound ion pumps. According to 16S ribosomal RNA analysis, the isolates belong to the candidate phylum Termite Group 3, representing its first culturable members. Phylogenetic analysis using ribosomal proteins and taxonomic distribution analysis of the whole proteome supported a class-level classification of ACht1 most probably affiliated to the phylum Fibribacteres. Based on phylogenetic, phenotypic and genomic analyses, the novel bacteria are proposed to be classified as Chitinivibrio alkaliphilus gen. nov., sp. nov., within a novel class Chitinivibrione. PMID:24112708

Sorokin, Dimitry Y; Gumerov, Vadim M; Rakitin, Andrey L; Beletsky, Alexey V; Damsté, J S Sinninghe; Muyzer, Gerard; Mardanov, Andrey V; Ravin, Nikolai V

2014-06-01

244

DNA extraction from protozoan oocysts/cysts in feces for diagnostic PCR.  

PubMed

PCR detection of intestinal protozoa is often restrained by a poor DNA recovery or by inhibitors present in feces. The need for an extraction protocol that can overcome these obstacles is therefore clear. QIAamp® DNA Stool Mini Kit (Qiagen) was evaluated for its ability to recover DNA from oocysts/cysts directly from feces. Twenty-five Giardia-positive, 15 Cryptosporidium-positive, 15 Entamoeba histolytica-positive, and 45 protozoa-free samples were processed as control by microscopy and immunoassay tests. DNA extracts were amplified using 3 sets of published primers. Following the manufacturer's protocol, the kit showed sensitivity and specificity of 100% towards Giardia and Entamoeba. However, for Cryptosporidium, the sensitivity and specificity were 60% (9/15) and 100%, respectively. A series of optimization experiments involving various steps of the kit's protocol were conducted using Cryptosporidium-positive samples. The best DNA recoveries were gained by raising the lysis temperature to the boiling point for 10 min and the incubation time of the InhibitEX tablet to 5 min. Also, using a pre-cooled ethanol for nucleic acid precipitation and small elution volume (50-100 µl) were valuable. The sensitivity of the amended protocol to Cryptosporidium was raised to 100%. Cryptosporidium DNA was successfully amplified by either the first or the second primer set. When applied on parasite-free feces spiked with variable oocysts/cysts counts, ? 2 oocysts/cysts were theoretically enough for detection by PCR. To conclude, the Qiagen kit with the amended protocol was proved to be suitable for protozoan DNA extraction directly from feces and support PCR diagnosis. PMID:25031466

Hawash, Yousry

2014-06-01

245

DNA Extraction from Protozoan Oocysts/Cysts in Feces for Diagnostic PCR  

PubMed Central

PCR detection of intestinal protozoa is often restrained by a poor DNA recovery or by inhibitors present in feces. The need for an extraction protocol that can overcome these obstacles is therefore clear. QIAamp® DNA Stool Mini Kit (Qiagen) was evaluated for its ability to recover DNA from oocysts/cysts directly from feces. Twenty-five Giardia-positive, 15 Cryptosporidium-positive, 15 Entamoeba histolytica-positive, and 45 protozoa-free samples were processed as control by microscopy and immunoassay tests. DNA extracts were amplified using 3 sets of published primers. Following the manufacturer's protocol, the kit showed sensitivity and specificity of 100% towards Giardia and Entamoeba. However, for Cryptosporidium, the sensitivity and specificity were 60% (9/15) and 100%, respectively. A series of optimization experiments involving various steps of the kit's protocol were conducted using Cryptosporidium-positive samples. The best DNA recoveries were gained by raising the lysis temperature to the boiling point for 10 min and the incubation time of the InhibitEX tablet to 5 min. Also, using a pre-cooled ethanol for nucleic acid precipitation and small elution volume (50-100 µl) were valuable. The sensitivity of the amended protocol to Cryptosporidium was raised to 100%. Cryptosporidium DNA was successfully amplified by either the first or the second primer set. When applied on parasite-free feces spiked with variable oocysts/cysts counts, ? 2 oocysts/cysts were theoretically enough for detection by PCR. To conclude, the Qiagen kit with the amended protocol was proved to be suitable for protozoan DNA extraction directly from feces and support PCR diagnosis.

2014-01-01

246

Field Application of a Subunit Vaccine against an Enteric Protozoan Disease  

PubMed Central

Background Coccidiosis is a major global veterinary health problem in intensively reared chickens. It is caused by apicomplexan parasites of the genus Eimeria. Principal Findings A subunit vaccine composed of purified antigens from the gametocytes of Eimeria maxima was used to stimulate the production and transfer of maternal antibodies between breeding hens and their hatchlings. The vaccine was injected into hens twice before they began laying eggs. Immunization had no adverse affects on egg laying or health of the hens and resulted in high antibody levels throughout the life of the hens. Progeny of immunized hens excreted significantly less oocysts of various species of Eimeria in their faeces than chicks from unvaccinated hens. Furthermore, the offspring of vaccinated hens developed stronger natural immunity to Eimeria, so that they were resistant to challenge infection even at 8 weeks of age, well after all maternal antibodies had left their circulation. Field trials were conducted in South Africa, Brazil and Thailand, involving at least 1 million progeny of vaccinated hens and at least 1 million positive control birds (raised on feed containing anticoccidial drugs or immunized with a live vaccine) in each country. Additionally, trials were carried out in Israel involving 60 million progeny of vaccinated hens and 112 million positive control birds. There were no significant differences in growth rate, feed conversion ratios or mortality in the offspring of vaccinated hens compared with the positive control chickens in any of these countries regardless of different management practices, different breeds of chickens or climate. Conclusions These results demonstrate that a vaccine composed of antigens purified from the gametocytes of Eimeria can be used safely and effectively to prevent the deleterious effects of coccidiosis. It is the first subunit vaccine against any protozoan parasite to be successfully applied on a commercial scale.

Wallach, Michael G.; Ashash, Udi; Michael, Amnon; Smith, Nicholas C.

2008-01-01

247

Molecular evidence for bacterial and protozoan pathogens in hard ticks from Romania.  

PubMed

The aim of the present study was to provide a preliminary insight into the diversity of tick-borne pathogens circulating at the domestic host-tick interface in Romania. For this, feeding and questing ticks were analyzed by real-time polymerase chain reaction (PCR) for the presence of Anaplasma phagocytophilum, Anaplasma platys, Ehrlichia canis, Borrelia burgdorferi sensu latu, and by PCR and subsequent sequencing for Rickettsia spp., Babesia spp. and Theileria spp. A total of 382 ticks, encompassing 5 species from 4 genera, were collected in April-July 2010 from different areas of Romania; of them, 40 were questing ticks and the remainder was collected from naturally infested cattle, sheep, goats, horses or dogs. Tick species analyzed included Ixodes ricinus, Dermacentor marginatus, Hyalomma marginatum, Rhipicephalus bursa, and Rhipicephalus sanguineus. Four rickettsiae of the spotted fever group of zoonotic concern were identified for the first time in Romania: Rickettsia monacensis and Rickettsia helvetica in I. ricinus, and Rickettsia slovaca and Rickettsia raoultii in D. marginatus. Other zoonotic pathogens such as A. phagocytophilum, Borrelia afzelii, and Babesia microti were found in I. ricinus. Pathogens of veterinary importance were also identified, including Theileria equi in H. marginatum, Babesia occultans in D. marginatus and H. marginatum, Theileria orientalis/sergenti/buffeli-group in I. ricinus and in H. marginatum and E. canis in R. sanguineus. These findings show a wide distribution of very diverse bacterial and protozoan pathogens at the domestic host-tick interface in Romania, with the potential of causing both animal and human diseases. PMID:23428204

Ionita, Mariana; Mitrea, Ioan Liviu; Pfister, Kurt; Hamel, Dietmar; Silaghi, Cornelia

2013-09-01

248

Risk of intestinal helminth and protozoan infection in a refugee population.  

PubMed

With continuing emigration from endemic countries, screening for parasitic infections remains a priority in U.S. communities serving refugee and immigrant populations. We report the prevalence of helminths and protozoa as well as demographic risk factors associated with these infections among 533 refugees seen at the Santa Clara County, California, Refugee Clinic between October 2001 and January 2004. Stool parasites were identified from 14% of refugees, including 9% found to have one or more protozoa and 6% found to have at least one helminth. Most common protozoan infections were Giardia lamblia (6%) and Dientamoeba fragilis (3%), and for helminths, hookworm (2%). Protozoa were more frequent in refugees < 18 years of age (OR: 2.2 [1.2-4.2]), whereas helminths were more common in refugees from South Central Asia (OR: 8.0 [2.3-27.7]) and Africa (OR: 5.9 [1.6-21.6]) when compared with refugees from Eastern Europe and the Middle East. Among helminths, Ascaris lumbricoides and hookworm were concentrated among South Central Asians (6 of 7 and 10 of 11 cases, respectively), whereas Strongyloides stercoralis was predominantly found in Africans (5 of 7 cases). Although predeparture empirical treatment programs in Saharan Africa may have helped to reduce prevalence among arriving refugees from this region, parasitic infection is still common among refugees to the United States with helminth infections found in more specific populations. As refugees represent only a fraction of recent immigrants from endemic countries, current studies in nonrefugee groups are also needed. PMID:16103610

Garg, Parveen K; Perry, Sharon; Dorn, Martha; Hardcastle, Laura; Parsonnet, Julie

2005-08-01

249

The natural resistance-associated macrophage protein from the protozoan parasite Perkinsus marinus mediates iron uptake.  

PubMed

Microbial pathogens succeed in acquiring essential metals such as iron and manganese despite their limited availability because of the host's immune response. The eukaryotic natural resistance-associated macrophage proteins mediate uptake of divalent metals and, during infection, may compete directly for metal acquisition with the pathogens' transporters. In this study, we characterize the Nramp gene family of Perkinsus marinus, an intracellular parasite of the eastern oyster, and through yeast complementation, we demonstrate for the first time for a protozoan parasite that Nramp imports environmental Fe. Three PmNramp isogenes differ in their exon-intron structures and encode transcripts that display a trans splicing leader at the 5' end. The protein sequences share conserved properties predicted for the Nramp/Solute carrier 11 (Slc11) family, such as 12-transmembrane segment (TMS) topology (N- and C-termini cytoplasmic) and preferential conservation of four TMS predicted to form a pseudosymmetric proton/metal symport pathway. Yeast fet3fet4 mutant complementation assays showed iron transport activity for PmNramp1 and a fusion chimera of the PmNramp3 hydrophobic core and PmNramp1 N- and C-termini. PmNramp1 site-directed mutagenesis demonstrated that Slc11 invariant and predicted pseudosymmetric motifs (TMS1 Asp-Pro-Gly and TMS6 Met-Pro-His) are key for transport function. PmNramp1 TMS1 mutants D76E, G78A, and D76E/G78A prevented membrane protein expression, while TMS6 M250A, H252Y, and M250A/H252Y specifically abrogated Fe uptake; the TMS6 H252Y mutation also correlates with divergence from Nramp specificity for divalent metals. PMID:21661746

Lin, Zhuoer; Fernández-Robledo, José-Antonio; Cellier, Mathieu F M; Vasta, Gerardo R

2011-07-26

250

Surface membrane carbohydrate alterations of a flagellated protozoan mediated by bacterial endosymbiotes.  

PubMed Central

Crithidia oncopelti, a parasitic trypanosomatid protozoan of insects, normally contains intracellular symbiotic bacteria. As shown earlier, the protozoa can be rid of their endosymbiotes by chloramphenicol, producing a symbiote-free cell line. Here surface-membrane carbohydrate ligands of the symbiote-containing and symbiote-free strains were compared by lectin-mediated agglutination, lectin-ultrastructure localization. [3H] lectin-binding, and fluorescent lectin staining. Symbiote-free organisms consistently had 3-fold higher agglutination titers than symbiote-containing cells with concanavalin A. Conversely, symbiote-containing flagellates had 2- to 3-fold greater agglutination titers with a fucose-binding lectin than symbiote-free organisms. Ultrastructure results showed that more of concanavalin A-horseradish peroxidase-diaminobenzidine reaction product was present at the surface of symbiote-free than on symbiote-containing cells. Treatment with [3H]concanavalin A revealed that surface membrane sites available per cell for [3H]lectin-binding ranged from 6.2 to 7.4 x 10(4) and from 24 to 27 x 10(4) for symbiote-containing and symbiote-free organisms, respectively, i.e., the mean binding level of the latter for the lectin was 3.5 times greater than that of the former. Moreover, symbiote-free cells fluoresced more than symbiote-containing organisms after staining with fluorescein-labeled concanavalin A. Apparently, the prokaryotic endosymbiotes somehow alter the quantity of saccharide ligands in the C. oncopelti surface membrane. Images

Dwyer, D M; Chang, K P

1976-01-01

251

A Type III Protein Arginine Methyltransferase from the Protozoan Parasite Trypanosoma brucei*  

PubMed Central

Arginine methylation is a widespread post-translational modification of proteins catalyzed by a family of protein arginine methyltransferases (PRMTs). The ancient protozoan parasite, Trypanosoma brucei, possesses five putative PRMTs, a relatively large number for a single-celled eukaryote. Trypanosomatids lack gene regulation at the level of transcription, instead relying on post-transcriptional control mechanisms that act at the levels of RNA turnover, translation, and editing, all processes that likely involve multiple RNA-binding proteins, which are common targets of arginine methylation. Here, we report the characterization of a trypanosome PRMT, TbPRMT7, which is homologous to human PRMT7. Interestingly, trypanosomatids are the only single-celled eukaryotes known to harbor a PRMT7 homologue. TbPRMT7 differs dramatically from all known metazoan PRMT7 homologues in lacking the second AdoMet binding-like domain that is required for activity of the human enzyme. Nevertheless, bacterially expressed TbPRMT7 exhibits robust methyltransferase activity toward multiple targets in vitro. High resolution ion exchange chromatography analysis of methylated substrates reveals that TbPRMT7 is a type III PRMT, catalyzing the formation of only monomethylarginine, thereby representing the only exclusively type III PRMT identified to date. TbPRMT7 is expressed in both mammalian and insect stage T. brucei and is apparently dispensable for growth in both life cycle stages. The enzyme is cytoplasmically localized and is a component of several higher order complexes in vivo. Together, our studies indicate that TbPRMT7 is a Type III PRMT, and its robust activity and presence in numerous complexes suggest it plays multiple roles during the complex T. brucei life cycle.

Fisk, John C.; Sayegh, Joyce; Zurita-Lopez, Cecilia; Menon, Sarita; Presnyak, Vladimir; Clarke, Steven G.; Read, Laurie K.

2009-01-01

252

Functional Characterization of Peroxiredoxins from the Human Protozoan Parasite Giardia intestinalis  

PubMed Central

The microaerophilic protozoan parasite Giardia intestinalis, causative of one of the most common human intestinal diseases worldwide, infects the mucosa of the proximal small intestine, where it has to cope with O2 and nitric oxide (NO). Elucidating the antioxidant defense system of this pathogen lacking catalase and other conventional antioxidant enzymes is thus important to unveil novel potential drug targets. Enzymes metabolizing O2, NO and superoxide anion (O2?•) have been recently reported for Giardia, but it is yet unknown how the parasite copes with H2O2 and peroxynitrite (ONOO?). Giardia encodes two yet uncharacterized 2-cys peroxiredoxins (Prxs), GiPrx1a and GiPrx1b. Peroxiredoxins are peroxidases implicated in virulence and drug resistance in several parasitic protozoa, able to protect from nitroxidative stress and repair oxidatively damaged molecules. GiPrx1a and a truncated form of GiPrx1b (deltaGiPrx1b) were expressed in Escherichia coli, purified and functionally characterized. Both Prxs effectively metabolize H2O2 and alkyl-hydroperoxides (cumyl- and tert-butyl-hydroperoxide) in the presence of NADPH and E. coli thioredoxin reductase/thioredoxin as the reducing system. Stopped-flow experiments show that both proteins in the reduced state react with ONOO? rapidly (k?=?4×105 M?1 s?1 and 2×105 M?1 s?1 at 4°C, for GiPrx1a and deltaGiPrx1b, respectively). Consistent with a protective role against oxidative stress, expression of GiPrx1a (but not deltaGiPrx1b) is induced in parasitic cells exposed to air O2 for 24 h. Based on these results, GiPrx1a and deltaGiPrx1b are suggested to play an important role in the antioxidant defense of Giardia, possibly contributing to pathogenesis.

Testa, Fabrizio; Pucillo, Leopoldo Paolo; Teixeira, Miguel; Sarti, Paolo; Saraiva, Ligia M.; Giuffre, Alessandro

2014-01-01

253

Protozoans as indicators of sequential batch processes for phenol treatment; an autoecological approach.  

PubMed

The objective of this study was the investigation of the potential use of protistan species as quality indicators of the activated sludge performance in sequential batch processes receiving toxic compounds. Two laboratory scale sequential batch reactors (SBR) were used, a conventional one and a system with plastic biofilm carriers (SBBR), treating wastewater containing phenol at concentrations ranging from 1 up to 40 mg/L. Physicochemical analyses of the samples included the determination of MLSS, effluent suspended solids, BOD5, nitrogen-ammonia, nitrogen-nitrate and phenol. The activated sludge protistan community was identified and enumerated in each reactor. Statistical analyses included Canonical Correspondence Analysis and Indicator Species Analysis of the collected experimental data. Canonical Correspondence Analysis showed inversely proportional relationships between the protozoa and the physicochemical parameters of the effluent as well as protozoan species competition. Indicator species analysis revealed the presence and the prevalence of different species under various phenol influent concentrations. No indicator species were observed for the period of operation under 5 mg/L influent phenol in both reactors, while no indicator species were observed for 20 mg/L influent phenol in the SBR reactor. Carchesium and Epistylis sp. showed the higher values for 1 mg/L phenol in the SBR, while Holophrya sp. showed lower indicator values for the same period in the SBBR. Although several species showed a good correlation to the treatment efficiency of the reactors, Blepharisma sp., could be used as the primary indicator species in both reactors for the operation period under 40 mg/L phenol, as deduced by statistical analysis. PMID:24070776

Papadimitriou, C A; Petridis, D; Zouboulis, A I; Samaras, P; Yiangou, M; Sakellaropoulos, G P

2013-12-01

254

Transcriptome Analysis of the Model Protozoan, Tetrahymena thermophila, Using Deep RNA Sequencing  

PubMed Central

Background The ciliated protozoan Tetrahymena thermophila is a well-studied single-celled eukaryote model organism for cellular and molecular biology. However, the lack of extensive T. thermophila cDNA libraries or a large expressed sequence tag (EST) database limited the quality of the original genome annotation. Methodology/Principal Findings This RNA-seq study describes the first deep sequencing analysis of the T. thermophila transcriptome during the three major stages of the life cycle: growth, starvation and conjugation. Uniquely mapped reads covered more than 96% of the 24,725 predicted gene models in the somatic genome. More than 1,000 new transcribed regions were identified. The great dynamic range of RNA-seq allowed detection of a nearly six order-of-magnitude range of measurable gene expression orchestrated by this cell. RNA-seq also allowed the first prediction of transcript untranslated regions (UTRs) and an updated (larger) size estimate of the T. thermophila transcriptome: 57 Mb, or about 55% of the somatic genome. Our study identified nearly 1,500 alternative splicing (AS) events distributed over 5.2% of T. thermophila genes. This percentage represents a two order-of-magnitude increase over previous EST-based estimates in Tetrahymena. Evidence of stage-specific regulation of alternative splicing was also obtained. Finally, our study allowed us to completely confirm about 26.8% of the genes originally predicted by the gene finder, to correct coding sequence boundaries and intron-exon junctions for about a third, and to reassign microarray probes and correct earlier microarray data. Conclusions/Significance RNA-seq data significantly improve the genome annotation and provide a fully comprehensive view of the global transcriptome of T. thermophila. To our knowledge, 5.2% of T. thermophila genes with AS is the highest percentage of genes showing AS reported in a unicellular eukaryote. Tetrahymena thus becomes an excellent unicellular model eukaryote in which to investigate mechanisms of alternative splicing.

Xiong, Jie; Lu, Xingyi; Zhou, Zhemin; Chang, Yue; Yuan, Dongxia; Tian, Miao; Zhou, Zhigang; Wang, Lei; Fu, Chengjie; Orias, Eduardo; Miao, Wei

2012-01-01

255

Dramatic Increase in Glycerol Biosynthesis upon Oxidative Stress in the Anaerobic Protozoan Parasite Entamoeba histolytica  

PubMed Central

Entamoeba histolytica, a microaerophilic enteric protozoan parasite, causes amebic colitis and extra intestinal abscesses in millions of inhabitants of endemic areas. Trophozoites of E. histolytica are exposed to a variety of reactive oxygen and nitrogen species during infection. Since E. histolytica lacks key components of canonical eukaryotic anti-oxidative defense systems, such as catalase and glutathione system, alternative not-yet-identified anti-oxidative defense strategies have been postulated to be operating in E. histolytica. In the present study, we investigated global metabolic responses in E. histolytica in response to H2O2- and paraquat-mediated oxidative stress by measuring charged metabolites on capillary electrophoresis and time-of-flight mass spectrometry. We found that oxidative stress caused drastic modulation of metabolites involved in glycolysis, chitin biosynthesis, and nucleotide and amino acid metabolism. Oxidative stress resulted in the inhibition of glycolysis as a result of inactivation of several key enzymes, leading to the redirection of metabolic flux towards glycerol production, chitin biosynthesis, and the non-oxidative branch of the pentose phosphate pathway. As a result of the repression of glycolysis as evidenced by the accumulation of glycolytic intermediates upstream of pyruvate, and reduced ethanol production, the levels of nucleoside triphosphates were decreased. We also showed for the first time the presence of functional glycerol biosynthetic pathway in E. histolytica as demonstrated by the increased production of glycerol 3-phosphate and glycerol upon oxidative stress. We proposed the significance of the glycerol biosynthetic pathway as a metabolic anti-oxidative defense system in E. histolytica.

Husain, Afzal; Sato, Dan; Jeelani, Ghulam; Soga, Tomoyoshi; Nozaki, Tomoyoshi

2012-01-01

256

Strain Differences in Fitness of Escherichia coli O157:H7 to Resist Protozoan Predation and Survival in Soil  

PubMed Central

Escherichia coli O157:H7 (EcO157) associated with the 2006 spinach outbreak appears to have persisted as the organism was isolated, three months after the outbreak, from environmental samples in the produce production areas of the central coast of California. Survival in harsh environments may be linked to the inherent fitness characteristics of EcO157. This study evaluated the comparative fitness of outbreak-related clinical and environmental strains to resist protozoan predation and survive in soil from a spinach field in the general vicinity of isolation of strains genetically indistinguishable from the 2006 outbreak strains. Environmental strains from soil and feral pig feces survived longer (11 to 35 days for 90% decreases, D-value) with Vorticella microstoma and Colpoda aspera, isolated previously from dairy wastewater; these D-values correlated (P<0.05) negatively with protozoan growth. Similarly, strains from cow feces, feral pig feces, and bagged spinach survived significantly longer in soil compared to clinical isolates indistinguishable by 11-loci multi-locus variable-number tandem-repeat analysis. The curli-positive (C+) phenotype, a fitness trait linked with attachment in ruminant and human gut, decreased after exposure to protozoa, and in soils only C? cells remained after 7 days. The C+ phenotype correlated negatively with D-values of EcO157 exposed to soil (rs?=??0.683; P?=?0.036), Vorticella (rs?=??0.465; P?=?0.05) or Colpoda (rs?=??0.750; P?=?0.0001). In contrast, protozoan growth correlated positively with C+ phenotype (Vorticella, rs?=?0.730, P?=?0.0004; Colpoda, rs?=?0.625, P?=?0.006) suggesting a preference for consumption of C+ cells, although they grew on C? strains also. We speculate that the C? phenotype is a selective trait for survival and possibly transport of the pathogen in soil and water environments.

Ravva, Subbarao V.; Sarreal, Chester Z.; Mandrell, Robert E.

2014-01-01

257

The elimination of helminth ova, faecal coliforms, Salmonella and protozoan cysts by various physicochemical processes in wastewater and sludge.  

PubMed

The removal of helminth ova, faecal coliforms, Salmonella and protozoan cysts by the application of physicochemical treatment processes to municipal wastewater and sludge was studied. In the first case, the advanced primary treatment (APT) process was studied, as well as filtration of the APT effluent. The APT sludge was treated with either lime or acid. The initial values of helminth ova, faecal coliforms, Salmonella and protozoan cysts in the wastewater were 23-27 eggs/L, 7.8 x 10(7)-6.5 x 10(8) MPN/100 mL, 4.5 x 10(5)-2.4 x 10(6) MPN/100 mL, and 1,007-1,814 cysts/L respectively. After APT treatment, 96% of the helminth ova, 1 log of faecal coliforms and Salmonella, and 67% of the protozoan cysts were eliminated. To reduce the concentration of helminth ova from values > 1.2 ova/L to < 1 ova/L an additional filtration step was required. In the sludge, the initial values of helminth ova, faecal coliforms and Salmonella were 65-120 ova/g TS, 8.3 x 10(7)-1.4 x 10(11) MPN/g TS and 3.6 x 10(6)-2.4 x 10(10) MPN/g TS respectively. A 97% reduction of the helminth and an 8.5 log reduction of faecal coliforms and Salmonella was achieved by alkaline stabilisation, compared with a 98% and 4.5 log reduction by acid treatment. PMID:11464750

Jiménez-Cisneros, B E; Maya-Rendón, C; Salgado-Velázquez, G

2001-01-01

258

Crystal structures of three protozoan homologs of tryptophanyl-tRNA synthetase.  

PubMed

Tryptophanyl-tRNA synthetase (TrpRS) is an essential enzyme that is recognizably conserved across all forms of life. It is responsible for activating and attaching tryptophan to a cognate tRNA(Trp) molecule for use in protein synthesis. In some eukaryotes this original core function has been supplemented or modified through the addition of extra domains or the expression of variant TrpRS isoforms. The three TrpRS structures from pathogenic protozoa described here represent three illustrations of this malleability in eukaryotes. The Cryptosporidium parvum genome contains a single TrpRS gene, which codes for an N-terminal domain of uncertain function in addition to the conserved core TrpRS domains. Sequence analysis indicates that this extra domain, conserved among several apicomplexans, is related to the editing domain of some AlaRS and ThrRS. The C. parvum enzyme remains fully active in charging tRNA(Trp) after truncation of this extra domain. The crystal structure of the active, truncated enzyme is presented here at 2.4? resolution. The Trypanosoma brucei genome contains separate cytosolic and mitochondrial isoforms of TrpRS that have diverged in their respective tRNA recognition domains. The crystal structure of the T. brucei cytosolic isoform is presented here at 2.8? resolution. The Entamoeba histolytica genome contains three sequences that appear to be TrpRS homologs. However one of these, whose structure is presented here at 3.0? resolution, has lost the active site motifs characteristic of the Class I aminoacyl-tRNA synthetase catalytic domain while retaining the conserved features of a fully formed tRNA(Trp) recognition domain. The biological function of this variant E. histolytica TrpRS remains unknown, but, on the basis of a completely conserved tRNA recognition region and evidence for ATP but not tryptophan binding, it is tempting to speculate that it may perform an editing function. Together with a previously reported structure of an unusual TrpRS from Giardia, these protozoan structures broaden our perspective on the extent of structural variation found in eukaryotic TrpRS homologs. PMID:21255615

Merritt, Ethan A; Arakaki, Tracy L; Gillespie, Robert; Napuli, Alberto J; Kim, Jessica E; Buckner, Frederick S; Van Voorhis, Wesley C; Verlinde, Christophe L M J; Fan, Erkang; Zucker, Frank; Hol, Wim G J

2011-05-01

259

Crystal structures of three protozoan homologs of tryptophanyl-tRNA synthetase  

PubMed Central

Tryptophanyl-tRNA synthetase (TrpRS) is an essential enzyme that is recognizably conserved across all forms of life. It is responsible for activating and attaching tryptophan to a cognate tRNATrp molecule for use in protein synthesis. In some eukaryotes this original core function has been supplemented or modified through the addition of extra domains or the expression of variant TrpRS isoforms. The three TrpRS structures from pathogenic protozoa described here represent three illustrations of this malleability in eukaryotes. The Cryptosporidium parvum genome contains a single TrpRS gene, which codes for an N-terminal domain of uncertain function in addition to the conserved core TrpRS domains. Sequence analysis indicates that this extra domain, conserved among several apicomplexans, is related to the editing domain of some AlaRS and ThrRS. The C. parvum enzyme remains fully active in charging tRNATrp after truncation of this extra domain. The crystal structure of the active, truncated enzyme is presented here at 2.4 Å resolution. The Trypanosoma brucei genome contains separate cytosolic and mitochondrial isoforms of TrpRS that have diverged in their respective tRNA recognition domains. The crystal structure of the T. brucei cytosolic isoform is presented here at 2.8 Å resolution. The Entamoeba histolytica genome contains three sequences that appear to be TrpRS homologs. However one of these, whose structure is presented here at 3.0 Å resolution, has lost the active site motifs characteristic of the Class I aminoacyl-tRNA synthetase catalytic domain while retaining the conserved features of a fully formed tRNATrp recognition domain. The biological function of this variant E. histolytica TrpRS remains unknown, but, on the basis of a completely conserved tRNA recognition region and evidence for ATP but not tryptophan binding, it is tempting to speculate that it may perform an editing function. Together with a previously reported structure of an unusual TrpRS from Giardia, these protozoan structures broaden our perspective on the extent of structural variation found in eukaryotic TrpRS homologs.

Arakaki, Tracy L; Gillespie, Robert; Napuli, Alberto J; Kim, Jessica E; Buckner, Frederick S; Van Voorhis, Wesley C; Verlinde, Christophe L M J; Fan, Erkang; Zucker, Frank; Hol, Wim G J

2011-01-01

260

Differential expression of mRNAs for alpha- and beta-tubulin during differentiation of the parasitic protozoan Leishmania mexicana.  

PubMed Central

The parasitic protozoan Leishmania mexicana amazonensis has two developmental stages: a motile flagellated promastigote stage and a sessile intracellular amastigote stage. In our previous work, cells of the promastigote stage were found to synthesize more tubulin protein than those of the amastigote stage. Here, tubulin mRNAs in these leishmanias were analyzed. Based on dot blot hybridization between total leishmanial RNA and tubulin-specific cDNA probes derived from chicken brain, amastigotes and promastigotes were found to have approximately equal amounts of alpha- and beta-tubulin mRNAs. RNA blotting of leishmanial RNA, using chicken tubulin cDNA probes, showed that amastigotes and promastigotes both gave a single mRNA species of 2100 nucleotides for alpha-tubulin in roughly similar quantities. However, such analysis for beta-tubulin revealed mainly a single mRNA species of 3600 nucleotides for amastigotes and three species of 2800, 3600, and 4400 nucleotides for promastigotes, the smallest mRNA being the most predominant. Thus, regulation of gene expression appears to be different only for beta-tubulin between the two developmental stages of this protozoan. Images

Fong, D; Wallach, M; Keithly, J; Melera, P W; Chang, K P

1984-01-01

261

Phylloseptins: a novel class of anti-bacterial and anti-protozoan peptides from the Phyllomedusa genus.  

PubMed

Six novel peptides called phylloseptins (PS-1, -2, -3, -4, -5, and -6) showing anti-bacterial (PS-1) and anti-protozoan (PS-4 and -5) activities were isolated from the skin secretion of the Brazilian tree-frogs, Phyllomedusa hypochondrialis and Phyllomedusa oreades. Phylloseptins have a primary structure consisting of 19-21 amino acid residues (1.7-2.1 kDa). They have common structural features, such as a highly conserved N-terminal region and C-terminal amidation. Phylloseptin-1 (FLSLIPHAINAVSAIAKHN-NH2) demonstrated a strong effect against gram-positive and gram-negative bacteria (MICs ranging from 3 to 7.9 microM), without showing significant hemolytic activity (<0.6% at the MIC range) towards mammalian cells. Atomic force microscopy experiments indicated that the bacteriolytic properties of these peptides might be related to their disruptive action on the cell membrane, characterized by a number of bubble-like formations, preceding every cell lysis. PS-4 and PS-5 showed anti-protozoan activity with IC50 at about 5 microM for Trypanosoma cruzi. PMID:15752569

Leite, José Roberto S A; Silva, Luciano P; Rodrigues, Maria Izabel S; Prates, Maura V; Brand, Guilherme D; Lacava, Bruno M; Azevedo, Ricardo B; Bocca, Anamélia L; Albuquerque, Sergio; Bloch, Carlos

2005-04-01

262

Seasonal incidence of protozoan parasites of the black tiger shrimp (Penaeus monodon) of Sundarbans, West Bengal, India.  

PubMed

There is a delicate balance between the host, pathogen and environment. Aquatic organisms, including shellfish, respond directly to climatic changes in their biological environment as their metabolic processes are influenced by temperature, salinity, and oxygen levels. Certain environmental conditions are more conducive to diseases than others among which water temperature is significantly associated with disease outbreak. The present study showed that Peneaus monodon of Sundarbans serve as a host for many protozoan parasites and epibionts including ciliates, gregarines and microsporidia. The protozoan parasites also require a particular environmental condition for their maximum growth and survival. The intensity of infection significantly increases with rise in temperature (P < 0.05) following a definite trend but no significant relationship between infection rate of ciliates and pH of water. In case of gregarine parasites significance (P < 0.05) exists among infection rate and temperature as well as pH of the farm water. Microsporidian parasites do not follow any significant seasonal trend in infecting the host P. monodon. PMID:22654317

Chakraborti, Jayati; Bandyapadhyay, Probir K

2011-06-01

263

Effect of vanadium toxicity at its different oxidation states on selected bacterial and protozoan isolates in wastewater systems.  

PubMed

This study assesses and compares vanadium toxicity in its different oxidation states towards bacterial isolates (Pseudomonas putida and Bacillus licheniformis) and protozoan isolates (Peranema sp. and Trachelophyllum sp.). The isolates were exposed to various concentrations of V in mixed liquors and their tolerance to V was assessed at 30 degrees C at a pH of 4. The results revealed that the increase in V oxidation state increased its toxicity to bacterial isolates, whereas its toxicity decreased for protozoan isolates. Among the bacterial isolates, P putida was found to be more tolerant to V3+(24h-median lethal concentration (LC50): 390mg/l), V4+(24h-LC50: 230-250mg/l) and V5+(24h-LC50: 180-200mg/l), whereas for the protozoan isolates, Peranema sp. appeared to be more tolerant to V3+(24 h-LC50: 110-120 mg/l), V4+(24 h-LC50: 160-170 mg/l) and V5+(24 h-LC50: 160-200 mg/l). A comparison of both groups of organisms revealed Trachelophyllum sp. as the most sensitive organism to V at its various oxidation states. The visual and spectrophotometric methods used to assess V reduction revealed that P. putida was the only isolate able to reduce V5+, V4+ and V3+ to V2+ in mixed liquor media. Vanadium (+2) in concentrations of approximately 46.46 mg/l, 29.57 m mg/l and 38.01 mg/l found in the media was treated with V3+, V4+ and V5+, respectively, and inoculated with P. putida. This study revealed that the ability of V reduction, adopted with P putida, can be an effective strategy to remove V from polluted environments. This study also showed that the toxicity of V, in terms of its oxidation states, differs from one species to another and in kingdoms. PMID:24956802

Kamika, Ilunga; Momba, Maggy N B

2014-08-01

264

Protozoan and myxozoan infections in wild gilthead seabream (Sparus aurata L.) from North Lake of Tunis, Tunisia.  

PubMed

A total of 150 gilthead seabream Sparus aurata L., from North Lake of Tunis, Tunisia, were studied for protozoan and myxozoan parasites. The parasitological survey revealed the presence of ectoparasites (Amyloodinium ocellatum Brown, 1931, Trichodina lepsii Lom, 1962 on the gills) and endoparasites (Ceratomyxa sparusaurati Sitjà-Bobadilla, Palenzuela et Alvarez-Pellitero, 1995 infecting the gallbladder, and Eimeria sparis Sitjà-Bobadilla, Palenzuela et Alvarez-Pellitero, 1996 parasitizing the intestine). This is the first record of Amyloodinium ocellatum, Trichodina lepsii, Ceratomyxa sparusaurati, and Eimeria sparis in S. aurata from Tunisian waters. Data on prevalence and intensity of infection are provided. A comparison of the present species with previously described species in cultured gilthead seabream from other Mediterranean countries is also presented. In this study Trichodina lepsii is identified for the first time in Sparus aurata. A taxonomic description of this species based on silver nitrate method is provided. PMID:22807047

Bahri, Sihem

2012-06-01

265

Identification of Particle Size Classes Inhibiting Protozoan Recovery from Surface Water Samples via U.S. Environmental Protection Agency Method 1623?  

PubMed Central

Giardia species recovery by U.S. Environmental Protection Agency method 1623 appears significantly impacted by a wide size range (2 to 30 ?m) of particles in water and organic matter. Cryptosporidium species recovery seems negatively correlated only with smaller (2 to 10 ?m), presumably inorganic particles. Results suggest constituents and mechanisms interfering with method performance may differ by protozoan type.

Krometis, Leigh-Anne H.; Characklis, Gregory W.; Sobsey, Mark D.

2009-01-01

266

Analysis of the transcriptome of the protozoan Theileria parva using MPSS reveals that the majority of genes are transcriptionally active in the schizont stage  

Microsoft Academic Search

Massively parallel signature sequencing (MPSS) was used to analyze the transcriptome of the intracellular protozoan Theileria parva. In total 1 095 000, 20 bp sequences representing 4371 different signatures were generated from T.parva schizonts. Repro- ducible signatures were identified within 73% of potentially detectable predicted genes and 83% had signatures in at least one MPSS cycle. A predicted leader peptide

Richard Bishop; Trushar Shah; Roger Pelle; David Hoyle; Terry Pearson; Lee Haines; Andrew Brass; Helen Hulme; Simon P. Graham; Evans L. N. Taracha; Simon Kanga; Charles Lu; Brian Hass; Jennifer R. Wortman; Owen White; Malcolm J. Gardner; Vishvanath Nene; Etienne P. de Villiers

2005-01-01

267

Global analysis of gene expression in response to L-Cysteine deprivation in the anaerobic protozoan parasite Entamoeba histolytica  

PubMed Central

Background Entamoeba histolytica, an enteric protozoan parasite, causes amebic colitis and extra intestinal abscesses in millions of inhabitants of endemic areas. E. histolytica completely lacks glutathione metabolism but possesses L-cysteine as the principle low molecular weight thiol. L-Cysteine is essential for the structure, stability, and various protein functions, including catalysis, electron transfer, redox regulation, nitrogen fixation, and sensing for regulatory processes. Recently, we demonstrated that in E. histolytica, L-cysteine regulates various metabolic pathways including energy, amino acid, and phospholipid metabolism. Results In this study, employing custom-made Affymetrix microarrays, we performed time course (3, 6, 12, 24, and 48 h) gene expression analysis upon L-cysteine deprivation. We identified that out of 9,327 genes represented on the array, 290 genes encoding proteins with functions in metabolism, signalling, DNA/RNA regulation, electron transport, stress response, membrane transport, vesicular trafficking/secretion, and cytoskeleton were differentially expressed (?3 fold) at one or more time points upon L-cysteine deprivation. Approximately 60% of these modulated genes encoded proteins of no known function and annotated as hypothetical proteins. We also attempted further functional analysis of some of the most highly modulated genes by L-cysteine depletion. Conclusions To our surprise, L-cysteine depletion caused only limited changes in the expression of genes involved in sulfur-containing amino acid metabolism and oxidative stress defense. In contrast, we observed significant changes in the expression of several genes encoding iron sulfur flavoproteins, a major facilitator super-family transporter, regulator of nonsense transcripts, NADPH-dependent oxido-reductase, short chain dehydrogenase, acetyltransferases, and various other genes involved in diverse cellular functions. This study represents the first genome-wide analysis of transcriptional changes induced by L-cysteine deprivation in protozoan parasites, and in eukaryotic organisms where L-cysteine represents the major intracellular thiol.

2011-01-01

268

Diarrhoea and malabsorption in acquired immune deficiency syndrome: a study of four cases with special emphasis on opportunistic protozoan infestations.  

PubMed Central

Chronic diarrhoea is frequent in acquired immune deficiency syndrome (AIDS) but has been poorly investigated so far. We report four patients with AIDS in whom diarrhoea and malabsorption were outstanding features, and who underwent extensive digestive investigations. Diarrhoea was a presenting symptom in all subjects and was of secretory type in three of them. D-xylose and vitamin B12 were malabsorbed in all cases; steatorrhea was found in the two patients who could ingest significant amounts of fat. Faecal alpha 1-antitrypsin clearance was increased in all subjects. Search for digestive pathogens showed unusual protozoans in all patients: in case 1, optical and electron microscopy revealed the presence in the cytoplasm of villous enterocytes of Microsporidia protozoans still unreported in AIDS. Stool and jejunal fluid examination showed Isospora belli in case 2 and Cryptosporidium in cases 3 and 4. On histological and ultrastructural study the former was localised in the cytoplasm of a few enterocytes and the latter was scattered throughout the villus and crypt brush border. Otherwise small intestinal histology only showed minor non-specific changes and the enterocytes were ultrastructurally normal. In patient 3 the slow marker intestinal perfusion technique showed a profuse fluid secretion in the duodenum and proximal jejunum. All patients needed prolonged total parenteral nutrition. Cryptosporidium and Microsporidia could not be eradicated despite multiple drug trials. Isospora belli was transiently cured by pyrimethamine-sulphadiazine. Only patient 2 is presently at home, and patients 1, 3, and 4 died after two, six, and nine months of total parenteral nutrition, respectively. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7

Modigliani, R; Bories, C; Le Charpentier, Y; Salmeron, M; Messing, B; Galian, A; Rambaud, J C; Lavergne, A; Cochand-Priollet, B; Desportes, I

1985-01-01

269

Application of magnetically induced hyperthermia in the model protozoan Crithidia fasciculata as a potential therapy against parasitic infections  

PubMed Central

Background Magnetic hyperthermia is currently a clinical therapy approved in the European Union for treatment of tumor cells, and uses magnetic nanoparticles (MNPs) under time-varying magnetic fields (TVMFs). The same basic principle seems promising against trypanosomatids causing Chagas disease and sleeping sickness, given that the therapeutic drugs available have severe side effects and that there are drug-resistant strains. However, no applications of this strategy against protozoan-induced diseases have been reported so far. In the present study, Crithidia fasciculata, a widely used model for therapeutic strategies against pathogenic trypanosomatids, was targeted with Fe3O4 MNPs in order to provoke cell death remotely using TVMFs. Methods Iron oxide MNPs with average diameters of approximately 30 nm were synthesized by precipitation of FeSO4 in basic medium. The MNPs were added to C. fasciculata choanomastigotes in the exponential phase and incubated overnight, removing excess MNPs using a DEAE-cellulose resin column. The amount of MNPs uploaded per cell was determined by magnetic measurement. The cells bearing MNPs were submitted to TVMFs using a homemade AC field applicator (f = 249 kHz, H = 13 kA/m), and the temperature variation during the experiments was measured. Scanning electron microscopy was used to assess morphological changes after the TVMF experiments. Cell viability was analyzed using an MTT colorimetric assay and flow cytometry. Results MNPs were incorporated into the cells, with no noticeable cytotoxicity. When a TVMF was applied to cells bearing MNPs, massive cell death was induced via a nonapoptotic mechanism. No effects were observed by applying TVMF to control cells not loaded with MNPs. No macroscopic rise in temperature was observed in the extracellular medium during the experiments. Conclusion As a proof of principle, these data indicate that intracellular hyperthermia is a suitable technology to induce death of protozoan parasites bearing MNPs. These findings expand the possibilities for new therapeutic strategies combating parasitic infection.

Grazu, V; Silber, AM; Moros, M; Asin, L; Torres, TE; Marquina, C; Ibarra, MR; Goya, GF

2012-01-01

270

Identification of scaffold/Matrix Attachment (S/MAR) like DNA element from the gastrointestinal protozoan parasite Giardia lamblia  

PubMed Central

Background Chromatin in the nucleus of all eukaryotes is organized into a system of loops and domains. These loops remain fastened at their bases to the fundamental framework of the nucleus, the matrix or the scaffold. The DNA sequences which anchor the bases of the chromatin loops to the matrix are known as Scaffold/Matrix Attachment Regions or S/MARs. Though S/MARs have been studied in yeast and higher eukaryotes and they have been found to be associated with gene organization and regulation of gene expression, they have not been reported in protists like Giardia. Several tools have been discovered and formulated to predict S/MARs from a genome of a higher eukaryote which take into account a number of features. However, the lack of a definitive consensus sequence in S/MARs and the randomness of the protozoan genome in general, make it a challenge to predict and identify such sequences from protists. Results Here, we have analysed the Giardia genome for the probable S/MARs predicted by the available computational tools; and then shown these sequences to be physically associated with the nuclear matrix. Our study also reflects that while no single computational tool is competent to predict such complex elements from protist genomes, a combination of tools followed by experimental verification is the only way to confirm the presence of these elements from these organisms. Conclusion This is the first report of S/MAR elements from the protozoan parasite Giardia lamblia. This initial work is expected to lay a framework for future studies relating to genome organization as well as gene regulatory elements in this parasite.

2010-01-01

271

Nitrolancea hollandica gen. nov., sp. nov., a chemolithoautotrophic nitrite-oxidizing bacterium isolated from a bioreactor belonging to the phylum Chloroflexi.  

PubMed

A novel nitrite-oxidizing bacterium (NOB), strain Lb(T), was isolated from a nitrifying bioreactor with a high loading of ammonium bicarbonate in a mineral medium with nitrite as the energy source. The cells were oval (lancet-shaped) rods with pointed edges, non-motile, Gram-positive (by staining and from the cell wall structure) and non-spore-forming. Strain Lb(T) was an obligately aerobic, chemolitoautotrophic NOB, utilizing nitrite or formate as the energy source and CO2 as the carbon source. Ammonium served as the only source of assimilated nitrogen. Growth with nitrite was optimal at pH 6.8-7.5 and at 40 °C (maximum 46 °C). The membrane lipids consisted of C20 alkyl 1,2-diols with the dominant fatty acids being 10MeC18 and C18?:?1?9. The peptidoglycan lacked meso-DAP but contained ornithine and lysine. The dominant lipoquinone was MK-8. Phylogenetic analyses of the 16s rRNA gene sequence placed strain Lb(T) into the class Thermomicrobia of the phylum Chloroflexi with Sphaerobacter thermophilus as the closest relative. On the basis of physiological and phylogenetic data, it is proposed that strain Lb(T) represents a novel species of a new genus, with the suggested name Nitrolancea hollandica gen. nov., sp. nov. The type strain of the type species is Lb(T) (?=?DSM 23161(T)?=?UNIQEM U798(T)). PMID:24573161

Sorokin, Dimitry Y; Vejmelkova, Dana; Lücker, Sebastian; Streshinskaya, Galina M; Rijpstra, W Irene C; Sinninghe Damsté, Jaap S; Kleerbezem, Robbert; van Loosdrecht, Mark; Muyzer, Gerard; Daims, Holger

2014-06-01

272

The search for the missing link: a relic plastid in Perkinsus?  

PubMed

Perkinsus marinus (Phylum Perkinsozoa) is a protozoan parasite that has devastated natural and farmed oyster populations in the USA, significantly affecting the shellfish industry and the estuarine environment. The other two genera in the phylum, Parvilucifera and Rastrimonas, are parasites of microeukaryotes. The Perkinsozoa occupies a key position at the base of the dinoflagellate branch, close to its divergence from the Apicomplexa, a clade that includes parasitic protista, many harbouring a relic plastid. Thus, as a taxon that has also evolved toward parasitism, the Perkinsozoa has attracted the attention of biologists interested in the evolution of this organelle, both in its ultrastructure and the conservation, loss or transfer of its genes. A review of the recent literature reveals mounting evidence in support of the presence of a relic plastid in P. marinus, including the presence of multimembrane structures, characteristic metabolic pathways and proteins with a bipartite N-terminal extension. Further, these findings raise intriguing questions regarding the potential functions and unique adaptation of the putative plastid and/or plastid genes in the Perkinsozoa. In this review we analyse the above-mentioned evidence and evaluate the potential future directions and expected benefits of addressing such questions. Given the rapidly expanding molecular/genetic resources and methodological toolbox for Perkinsus spp., these organisms should complement the currently established models for investigating plastid evolution within the Chromalveolata. PMID:21889509

Fernández Robledo, José A; Caler, Elisabet; Matsuzaki, Motomichi; Keeling, Patrick J; Shanmugam, Dhanasekaran; Roos, David S; Vasta, Gerardo R

2011-10-01

273

Microbial community analysis in the roots of aquatic plants and isolation of novel microbes including an organism of the candidate phylum OP10.  

PubMed

A number of molecular ecological studies have revealed complex and unique microbial communities in various terrestrial plant roots; however, little is known about the microbial communities of aquatic plant roots in spite of their potential use for water quality improvement in aquatic environments (e.g. floating treatment wetland system). Here, we report the microbial communities inhabiting the roots of emerged plants, reed (Phragmites australis) and Japanese loosestrife (Lythrum anceps), collected from a floating treatment wetland in a pond by both culture-independent and culture-dependent approaches. Culture-independent analysis based on 16S rRNA gene sequences revealed that the microbial compositions between the two aquatic plant roots were clearly different (e.g. the predominant microbe was Betaproteobacteria for reed and Alphaproteobacteria for Japanese loosestrife). In comparisons of microbial communities between the plant roots and pond water taken from near the plants, the microbial diversity in the plant roots (e.g. 4.40-4.26 Shannon-Weiner index) were higher than that of pond water (e.g. 3.15 Shannon-Weiner index). Furthermore, the plant roots harbored 2.5-3.5 times more phylogenetically novel clone phylotypes than pond water. The culture-dependent approach also revealed differences in the microbial composition and diversity among the two plant roots and pond water. More importantly, compared to pond water, we succeeded in isolating approximately two times more novel isolate phylotypes, including a bacterium of candidate phylum OP10 (recently named Armatimonadetes) from the plant roots. These findings suggest that aquatic plants roots are significant sources for a variety of novel organisms. PMID:22791047

Tanaka, Yasuhiro; Tamaki, Hideyuki; Matsuzawa, Hiroaki; Nigaya, Masahiro; Mori, Kazuhiro; Kamagata, Yoichi

2012-01-01

274

Terrimicrobium sacchariphilum gen. nov., sp. nov., an anaerobic bacterium of the class 'Spartobacteria' in the phylum Verrucomicrobia, isolated from a rice paddy field.  

PubMed

A strictly anaerobic, mesophilic, carbohydrate-fermenting bacterium, designated NM-5(T), was isolated from a rice paddy field. Cells of strain NM-5(T) were Gram-stain-negative, non-motile, non-spore-forming, short rods (0.5-0.7 µm×0.6-1.2 µm). The strain grew optimally at 37 °C (growth range 20-40 °C) and pH 7.0 (pH 5.5-8.0). The strain could grow fermentatively on arabinose, xylose, fructose, galactose, glucose, ribose, mannose, cellobiose, lactose, maltose and sucrose. The main end-products of glucose fermentation were acetate and propionate. Organic acids, alcohols and amino acids were not utilized for growth. Yeast extract was not required but stimulated the growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite, and Fe (III) nitrilotriacetate were not used as terminal electron acceptors. The DNA G+C content was 46.3 mol%. The major cellular fatty acids were iso-C14?:?0, C18?:?0 and C16?:?0. 16S rRNA gene sequence analysis revealed that strain NM-5(T) belongs to the class 'Spartobacteria', subdivision 2 of the bacterial phylum Verrucomicrobia. Phylogenetically, the closest species was 'Chthoniobacter flavus' (89.6?% similarity in 16S rRNA gene sequence). A novel genus and species, Terrimicrobium sacchariphilum gen. nov., sp. nov., is proposed. The type strain of the type species is NM-5(T) (?=?JCM 17479(T)?=?CGMCC 1.5168(T)). PMID:24535138

Qiu, Yan-Ling; Kuang, Xiao-Zhu; Shi, Xiao-Shuang; Yuan, Xian-Zheng; Guo, Rong-Bo

2014-05-01

275

Microbial Community Analysis in the Roots of Aquatic Plants and Isolation of Novel Microbes Including an Organism of the Candidate Phylum OP10  

PubMed Central

A number of molecular ecological studies have revealed complex and unique microbial communities in various terrestrial plant roots; however, little is known about the microbial communities of aquatic plant roots in spite of their potential use for water quality improvement in aquatic environments (e.g. floating treatment wetland system). Here, we report the microbial communities inhabiting the roots of emerged plants, reed (Phragmites australis) and Japanese loosestrife (Lythrum anceps), collected from a floating treatment wetland in a pond by both culture-independent and culture-dependent approaches. Culture-independent analysis based on 16S rRNA gene sequences revealed that the microbial compositions between the two aquatic plant roots were clearly different (e.g. the predominant microbe was Betaproteobacteria for reed and Alphaproteobacteria for Japanese loosestrife). In comparisons of microbial communities between the plant roots and pond water taken from near the plants, the microbial diversity in the plant roots (e.g. 4.40–4.26 Shannon-Weiner index) were higher than that of pond water (e.g. 3.15 Shannon-Weiner index). Furthermore, the plant roots harbored 2.5–3.5 times more phylogenetically novel clone phylotypes than pond water. The culture-dependent approach also revealed differences in the microbial composition and diversity among the two plant roots and pond water. More importantly, compared to pond water, we succeeded in isolating approximately two times more novel isolate phylotypes, including a bacterium of candidate phylum OP10 (recently named Armatimonadetes) from the plant roots. These findings suggest that aquatic plants roots are significant sources for a variety of novel organisms.

Tanaka, Yasuhiro; Tamaki, Hideyuki; Matsuzawa, Hiroaki; Nigaya, Masahiro; Mori, Kazuhiro; Kamagata, Yoichi

2012-01-01

276

Synthesis, Solution Structure, and Phylum Selectivity of a Spider ?-Toxin That Slows Inactivation of Specific Voltage-gated Sodium Channel Subtypes*  

PubMed Central

Magi 4, now renamed ?-hexatoxin-Mg1a, is a 43-residue neurotoxic peptide from the venom of the hexathelid Japanese funnel-web spider (Macrothele gigas) with homology to ?-hexatoxins from Australian funnel-web spiders. It binds with high affinity to receptor site 3 on insect voltage-gated sodium (NaV) channels but, unlike ?-hexatoxins, does not compete for the related site 3 in rat brain despite being previously shown to be lethal by intracranial injection. To elucidate differences in NaV channel selectivity, we have undertaken the first characterization of a peptide toxin on a broad range of mammalian and insect NaV channel subtypes showing that ?-hexatoxin-Mg1a selectively slows channel inactivation of mammalian NaV1.1, NaV1.3, and NaV1.6 but more importantly shows higher affinity for insect NaV1 (para) channels. Consequently, ?-hexatoxin-Mg1a induces tonic repetitive firing of nerve impulses in insect neurons accompanied by plateau potentials. In addition, we have chemically synthesized and folded ?-hexatoxin-Mg1a, ascertained the bonding pattern of the four disulfides, and determined its three-dimensional solution structure using NMR spectroscopy. Despite modest sequence homology, we show that key residues important for the activity of scorpion ?-toxins and ?-hexatoxins are distributed in a topologically similar manner in ?-hexatoxin-Mg1a. However, subtle differences in the toxin surfaces are important for the novel selectivity of ?-hexatoxin-Mg1a for certain mammalian and insect NaV channel subtypes. As such, ?-hexatoxin-Mg1a provides us with a specific tool with which to study channel structure and function and determinants for phylum- and tissue-specific activity.

Yamaji, Nahoko; Little, Michelle J.; Nishio, Hideki; Billen, Bert; Villegas, Elba; Nishiuchi, Yuji; Tytgat, Jan; Nicholson, Graham M.; Corzo, Gerardo

2009-01-01

277

Chthoniobacter flavus gen. nov., sp. nov., the first pure-culture representative of subdivision two, spartobacteria classis nov., of the phylum verrucomicrobia  

SciTech Connect

The phylum Verrucomicrobia is increasingly recognized as an environmentally significant group of bacteria, particularly in soil habitats. At least six subdivisions of the Verrucomicrobia are resolved by comparative analysis of 16S rRNA genes, mostly obtained directly from environmental samples. To date, only two of these subdivisions (1 and 4) have characterized pure-culture representatives. We have isolated and characterized the first known pure-culture representative of subdivision 2. Strain Ellin428 is an aerobic heterotrophic bacterium that is able to grow with many of the saccharide components of plant biomass but does not grow with amino acids or organic acids other than pyruvate. Cells are yellow, rod-shaped, nonmotile, and gram-stain negative, and they contain peptidoglycan with direct cross-linkages of the A1{gamma} meso-Dpm type. The isolate grows well at 25 C on a variety of standard biological media, including some used in the routine cultivation of bacteria from soil. The pH range for growth is 4.0 to 7.0. Low levels of menaquinones MK-10 and MK-11 were detected. The major cellular fatty acids are C{sub 14:0}, a-C{sub 15:0}, C{sub 16:1{omega}7c}, and/or 2OH i-C{sub 15:0}, and C{sub 16:0}. The G+C content of the genomic DNA is 61 mol percent. We propose a new genus and species, Chthoniobacter flavus gen. nov., sp. nov., with isolate Ellin428 as the type strain, and a new class for the subdivision to which it belongs, Spartobacteria classis nov. Environmental sequences indicate that the class Spartobacteria is largely represented by globally distributed, abundant, and active soil bacteria.

Sangwan, Parveen; Chen, Xiaolei; Hugenholtz, Philip; Janssen, Peter H.

2004-03-15

278

Extrachromosomal DNA in the Apicomplexa.  

PubMed Central

Malaria and related apicomplexan parasites have two highly conserved organellar genomes: one is of plastid (pl) origin, and the other is mitochondrial (mt). The organization of both organellar DNA molecules from the human malaria parasite Plasmodium falciparum has been determined, and they have been shown to be tightly packed with genes. The 35-kb circular DNA is the smallest known vestigial plastid genome and is presumed to be functional. All but two of its recognized genes are involved with genetic expression: one of the two encodes a member of the clp family of molecular chaperones, and the other encodes a conserved protein of unknown function found both in algal plastids and in eubacterial genomes. The possible evolutionary source and intracellular location of the plDNA are discussed. The 6-kb tandemly repeated mt genome is the smallest known and codes for only three proteins (cytochrome b and two subunits of cytochrome oxidase) as well as two bizarrely fragmented rRNAs. The organization of the mt genome differs somewhat among genera. The mtDNA sequence provides information not otherwise available about the structure of apicomplexan cytochrome b as well as the unusually fragmented rRNAs. The malarial mtDNA has a phage-like replication mechanism and undergoes extensive recombination like the mtDNA of some other lower eukaryotes.

Wilson, R J; Williamson, D H

1997-01-01

279

Temporal population dynamics of dinoflagellate Prorocentrum minimum in a semi-enclosed mariculture pond and its relationship to environmental factors and protozoan grazers  

NASA Astrophysics Data System (ADS)

The ecological processes and interrelationships between protists, either autotrophic or heterotrophic, and environmental factors in mariculture ponds are largely unknown. This study investigated the temporal dynamics of potentially harmful dinoflagellate, Prorocentrum minimum (Pavillard) Schiller, and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao, Northern China. P. minimum occurred frequently in low numbers from June to August, followed by a sharp increase from the middle of August, reaching a single maximum peak value of 2.2×105 cells L-1 in October. Temporal variation in abundance was positively correlated with dissolved nitrogen, but showed a significant inverse relationship to abundance of the dominant ciliates, Tintinnopsis lohmanni and Askenasia stellaris. The results provide statistical evidence that the number of P. minimum increased with increasing nitrogen, and the suppression or shortening of algal bloom may be associated with protozoan grazers, such as Tintinnopsis lohmanni, in mariculture ponds.

Xu, Henglong; Min, Gi-Sik; Choi, Joong-Ki; Zhu, Mingzhuang; Jiang, Yong; Al-Rasheid, Khaled A. S.

2010-01-01

280

Molecular cloning and characterization of a novel glutathione S-transferase gene induced by light stimulation in the protozoan Blepharisma japonicum.  

PubMed

A cDNA clone that is inducible by light stimulation was cloned by a differential screening method from a cDNA library of the protozoan Blepharisma japonicum, and the light-dependent expression was checked by semi-quantitative reverse transcription polymerase chain reaction analysis. Sequence analysis showed that the cDNA encodes a glutathione S-transferase (GST) that has not been characterized in the protozoa. Multiple alignment of B. japonicum GST (BjGST1), known protozoan, and mammalian alpha-, micro-, pi-, sigma-, theta-, zeta-, kappa-, and omega-class GSTs suggested that the BjGST1 may be a novel class GST. Furthermore, highly conserved amino acid residues among the GSTs and the substrate specificity of recombinant BjGST1 showed that BjGST1 is related to alpha-, micro-, pi-, and sigma-class GSTs rather than the other class of GSTs. PMID:14987763

Takada, Yuichi; Uda, Kouji; Kawamura, Kazuo; Matsuoka, Tatsuomi

2004-02-16

281

Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common  

USGS Publications Warehouse

We explored associations between the common protozoan parasite Toxoplasma gondii and brain cancers in human populations. We predicted that T. gondii could increase the risk of brain cancer because it is a long-lived parasite that encysts in the brain, where it provokes inflammation and inhibits apoptosis. We used a medical geography approach based on the national incidence of brain cancers and seroprevalence of T. gondii. We corrected reports of incidence for national gross domestic product because wealth probably increases the ability to detect cancer. We also included gender, cell phone use and latitude as variables in our initial models. Prevalence of T. gondii explained 19 per cent of the residual variance in brain cancer incidence after controlling for the positive effects of gross domestic product and latitude among nations. Infection with T. gondii was associated with a 1.8-fold increase in the risk of brain cancers across the range of T. gondii prevalence in our dataset (4-67%). These results, though correlational, suggest that T. gondii should be investigated further as a possible oncogenic pathogen of humans. ?? 2011 The Royal Society.

Thomas, F.; Lafferty, K. D.; Brodeur, J.; Elguero, E.; Gauthier-Clerc, M.; Misse, D.

2012-01-01

282

Tubulin biosynthesis in the developmental cycle of a parasitic protozoan, Leishmania mexicana: changes during differentiation of motile and nonmotile stages.  

PubMed Central

Cytodifferentiation in the transition cycle of the parasitic protozoan Leishmania mexicana amazonensis was studied in vitro. The flagellated motile promastigotes transform into the nonmotile amastigotes in 7 days at 35 degrees C intracellularly in the murine macrophage line J774G8. In medium 199 plus fetal bovine serum, the reverse transformation occurs extracellularly at 27 degrees C in 2 days. Slab gel electrophoresis of leishmanias labeled with [35S]methionine during transformation revealed changes in protein banding patterns. The intensity of two protein species with apparent molecular weights of approximately equal to 55,000 increased in the amastigote-to-promastigote differentiation and decreased during the reverse transformation. These two protein species comigrated approximately with alpha- and beta-tubulin of Chlamydomonas flagella in two-dimensional gel electrophoresis. The lower band was further identified as beta-tubulin by immunoprecipitation using rabbit antiserum specific to the beta-tubulin of Chlamydomonas axonemes. The biosynthetic change of tubulin was found to correlate with the morphological change of microtubules is leishmanial flagella and cytoskeleton during transformation. Images

Fong, D; Chang, K P

1981-01-01

283

Protozoans bacterivory in a subtropical environment during a dry/cold and a rainy/warm season  

PubMed Central

In aquatic ecosystems, bacteria are controlled by several organisms in the food chain, such as protozoa, that use them as food source. This study aimed to quantify the ingestion and clearance rates of bacteria by ciliates and heterotrophic nanoflagellates (HNF) in a subtropical freshwater reservoir (Monjolinho reservoir - São Carlos - Brazil) during one year period, in order to verify their importance as consumers and controllers of bacteria in two seasons, a dry/cold and a rainy/warm one. For this purpose, in situ bacterivory experiments were carried out bimonthly using fluorescently labeled bacteria with 5-(4,6 diclorotriazin-2yl) aminofluorescein (DTAF). Although ciliates have shown the highest individual ingestion and clearance rates, bacterivory was dominated by HNF, who showed higher population ingestion rates (mean of 9,140 bacteria h?1 mL?1) when compared to ciliates (mean of 492 bacteria h?1 mL?1). The greater predation impact on bacterial communities was caused mainly by the small HNF (< 5 ?m) population, especially in the rainy season, probably due to the abundances of these organisms, the precipitation, trophic index state and water temperature that were higher in this period. Thus, the protozoan densities together with environmental variables were extremely relevant in determining the seasonal pattern of bacterivory in Monjolinho reservoir.

Hisatugo, Karina F.; Mansano, Adrislaine S.; Seleghim, Mirna H.R.

2014-01-01

284

Cryo-EM structure of the Plasmodium falciparum 80S ribosome bound to the anti-protozoan drug emetine  

PubMed Central

Malaria inflicts an enormous burden on global human health. The emergence of parasite resistance to front-line drugs has prompted a renewed focus on the repositioning of clinically approved drugs as potential anti-malarial therapies. Antibiotics that inhibit protein translation are promising candidates for repositioning. We have solved the cryo-EM structure of the cytoplasmic ribosome from the human malaria parasite, Plasmodium falciparum, in complex with emetine at 3.2 Å resolution. Emetine is an anti-protozoan drug used in the treatment of ameobiasis that also displays potent anti-malarial activity. Emetine interacts with the E-site of the ribosomal small subunit and shares a similar binding site with the antibiotic pactamycin, thereby delivering its therapeutic effect by blocking mRNA/tRNA translocation. As the first cryo-EM structure that visualizes an antibiotic bound to any ribosome at atomic resolution, this establishes cryo-EM as a powerful tool for screening and guiding the design of drugs that target parasite translation machinery. DOI: http://dx.doi.org/10.7554/eLife.03080.001

Wong, Wilson; Bai, Xiao-chen; Brown, Alan; Fernandez, Israel S; Hanssen, Eric; Condron, Melanie; Tan, Yan Hong; Baum, Jake; Scheres, Sjors HW

2014-01-01

285

Cysteine protease-binding protein family 6 mediates the trafficking of amylases to phagosomes in the enteric protozoan Entamoeba histolytica.  

PubMed

Phagocytosis plays a pivotal role in nutrient acquisition and evasion from the host defense systems in Entamoeba histolytica, the intestinal protozoan parasite that causes amoebiasis. We previously reported that E. histolytica possesses a unique class of a hydrolase receptor family, designated the cysteine protease-binding protein family (CPBF), that is involved in trafficking of hydrolases to lysosomes and phagosomes, and we have also reported that CPBF1 and CPBF8 bind to cysteine proteases or ?-hexosaminidase ?-subunit and lysozymes, respectively. In this study, we showed by immunoprecipitation that CPBF6, one of the most highly expressed CPBF proteins, specifically binds to ?-amylase and ?-amylase. We also found that CPBF6 is localized in lysosomes, based on immunofluorescence imaging. Immunoblot and proteome analyses of the isolated phagosomes showed that CPBF6 mediates transport of amylases to phagosomes. We also demonstrated that the carboxyl-terminal cytosolic region of CPBF6 is engaged in the regulation of the trafficking of CPBF6 to phagosomes. Our proteome analysis of phagosomes also revealed new potential phagosomal proteins. PMID:23509141

Furukawa, Atsushi; Nakada-Tsukui, Kumiko; Nozaki, Tomoyoshi

2013-05-01

286

Introduction of Caveolae Structural Proteins into the Protozoan Toxoplasma Results in the Formation of Heterologous Caveolae but Not Caveolar Endocytosis  

PubMed Central

Present on the plasma membrane of most metazoans, caveolae are specialized microdomains implicated in several endocytic and trafficking mechanisms. Caveolins and the more recently discovered cavins are the major protein components of caveolae. Previous studies reported that caveolar invaginations can be induced de novo on the surface of caveolae-negative mammalian cells upon heterologous expression of caveolin-1. However, it remains undocumented whether other components in the transfected cells participate in caveolae formation. To address this issue, we have exploited the protozoan Toxoplasma as a heterologous expression system to provide insights into the minimal requirements for caveogenesis and caveolar endocytosis. Upon expression of caveolin-1, Toxoplasma accumulates prototypical exocytic caveolae ‘precursors’ in the cytoplasm. Toxoplasma expressing caveolin-1 alone, or in conjunction with cavin-1, neither develops surface-located caveolae nor internalizes caveolar ligands. These data suggest that the formation of functional caveolae at the plasma membrane in Toxoplasma and, by inference in all non-mammalian cells, requires effectors other than caveolin-1 and cavin-1. Interestingly, Toxoplasma co-expressing caveolin-1 and cavin-1 displays an impressive spiraled network of membranes containing the two proteins, in the cytoplasm. This suggests a synergistic activity of caveolin-1 and cavin-1 in the morphogenesis and remodeling of membranes, as illustrated for Toxoplasma.

Lige, Bao; Sonda, Sabrina; Joiner, Keith A.; Coppens, Isabelle

2012-01-01

287

The water-born protein pheromones of the polar protozoan ciliate, Euplotes nobilii: Coding genes and molecular structures  

NASA Astrophysics Data System (ADS)

The protozoan ciliate Euplotes nobilii found in Antarctic and Arctic coastal waters relies on secretion of water-soluble cell type-specific signal proteins (pheromones) to regulate its vegetative growth and sexual mating. For three of these psychrophilic pheromones we previously determined the three-dimensional structures by nuclear magnetic resonance (NMR) spectroscopy with protein solutions purified from the natural sources, which led to evidence that their adaptation to cold is primarily achieved by increased flexibility through an extension of regions free of regular secondary structures, and by increased exposure of negative charges on the protein surface. Then we cloned the coding genes of these E. nobilii pheromones from the transcriptionally active cell somatic nucleus (macronucleus) and characterized the full-length sequences. These sequences all contain an open reading frame of 252-285 nucleotides, which is specific for a cytoplasmic pheromone precursor that requires two proteolytic cleavages to remove a signal peptide and a pro segment before release of the mature protein into the extracellular environment. The 5? and 3? non-coding regions are two- to three-fold longer than the coding region and appear to be tightly conserved, probably in relation to the inclusion of intron sequences destined to be alternatively removed to play key regulatory roles in the mechanism of the pheromone gene expression.

Vallesi, Adriana; Alimenti, Claudio; Di Giuseppe, Graziano; Dini, Fernando; Pedrini, Bill; Wüthrich, Kurt; Luporini, Pierangelo

2010-08-01

288

Identification of particle size classes inhibiting protozoan recovery from surface water samples via U.S. Environmental Protection Agency method 1623.  

PubMed

Giardia species recovery by U.S. Environmental Protection Agency method 1,623 appears significantly impacted by a wide size range (2 to 30 microm) of particles in water and organic matter. Cryptosporidium species recovery seems negatively correlated only with smaller (2 to 10 microm), presumably inorganic particles. Results suggest constituents and mechanisms interfering with method performance may differ by protozoan type. PMID:19684177

Krometis, Leigh-Anne H; Characklis, Gregory W; Sobsey, Mark D

2009-10-01

289

Prevalence and pathology of the nematode Heterakis gallinarum, the trematode Paratanaisia bragai, and the protozoan Histomonas meleagridis in the turkey, Meleagris gallopavo.  

PubMed

The prevalence of infection and associated pathology induced by two helminth and one protozoan species infecting Brazilian turkeys are reported. The intestinal nematode Heterakis gallinarum appeared with a prevalence of 70% in the infected birds, without gross lesions when not associated to the protozoan Histomonas meleagridis. Histological findings in the ceca were represented by the presence of H. gallinarum worms, intense chronic diffuse inflammatory processes with mononuclear and polymorphonuclear (heterophils) leucocyte infiltrations. The prevalence of the protozoan H. meleagridis associated to H. gallinarum was of 2.5% and microscopic examination revealed a severe inflammatory process in the liver and cecum with the presence of small clear areas with round eosinophilic parasites. Gross lesions were absent in turkeys infected with the renal digenetic trematode Paratanaisia bragai; the parasite was prevalent in 20% of the cases and cross-sections of the kidneys showed a remarkable distension of the collecting ducts with several worms in the lumen. The walls of the ducts presented a discrete heterophilic infiltrate among mononuclear cells. PMID:17072483

Brener, Beatriz; Tortelly, Rogério; Menezes, Rodrigo Caldas; Muniz-Pereira, Luís C; Pinto, Roberto Magalhães

2006-09-01

290

[Presence of intestinal parasites in vegetables sold in the metropolitan area of São Paulo-SP, Brazil. II--Research on intestinal protozoans].  

PubMed

Vegetables in nature, commercially traded in the metropolitan area of S. Paulo, Brazil, were analyzed by means of the appropriate methodology with a view to discovering and identifying protozoan cysts of medical interest. The vegetables under study consisted of 50 samples of each of the varieties listed below: lettuce (Lactuca sativa)-oily leaves and crisp-head varieties, endive (Chicorium sp) and watercress (Nasturtium officinale). Results showed high rates of contamination in all the varieties of vegetable analysed. However, the watercress was the one which presented the highest frequencies of enteroparasites. Both the oily leaves and crisp-head varieties of lettuce presented the lowest rates of contamination, whereas endive presented values ranking, in general, between those of the lettuce and those of the watercress. A great variety of those protozoans which occur frequently in the population resident in the metropolitan area of S. Paulo were observed in the samples, the most frequent being Entamoeba sp (with 4 and 8 nuclei) and Giardia sp. Cysts of Iodamoeba sp, Endolimax sp and Chilomastix sp were also recovered from the samples, thus corroborating the occurrence of high rates of fecal contamination. The significance of these kinds of food in the transmission of protozoans is discussed in the light of the results obtained. PMID:1342522

de Oliveira, C A; Germano, P M

1992-10-01

291

The Ciliated Protists: Phylum Ciliophora  

NSDL National Science Digital Library

BioMEDIA Associates has added two new image galleries -- ciliated protists and bacteria -- to its online collection of educational materials on the diversity of life. While many of the products created by BioMEDIA must be purchased, their image galleries may be viewed free of charge. The two new galleries each contain beautiful, colorful photos that are as much digital art as they are teaching tools for biology. Some of the images contain related roll-over text describing some aspect of the organism's biology. The ciliate gallery would be especially useful for students attempting to locate ciliate specimens under the microscope for the first time, providing them with a clear search image. The ciliate gallery also includes a free video clip about ciliate diversity, best viewed with a high-speed connection.

2002-01-01

292

Phylum: Tardigrada (water bears, tardigrades)  

NSDL National Science Digital Library

This web page describes water bears, minute animals that can remain dormant in a dry state for over 100 years. The page addresses what they are, where they are found, their general biology, cryptobiosis, their ability to resist environmental extremes, implications and further research regarding their cryptobiosis, where they fit in with other animals, and their existence in South Africa. It also describes how someone could collect and see them. The page is part of Biodiversity Explorer, a web site hosted by Iziko Museums of Cape Town that features the diversity of life in South Africa.

Middleton, Roger; Town, Iziko M.

293

Lactivibrio alcoholicus gen. nov., sp. nov., an anaerobic, mesophilic, lactate-, alcohol-, carbohydrate- and amino-acid-degrading bacterium in the phylum Synergistetes.  

PubMed

A mesophilic, obligately anaerobic, lactate-, alcohol-, carbohydrate- and amino-acid- degrading bacterium, designated strain 7WAY-8-7(T), was isolated from an upflow anaerobic sludge blanket reactor treating high-strength organic wastewater from isomerized sugar production processes. Cells of strain 7WAY-8-7(T) were motile, curved rods (0.7-1.0×5.0-8.0 µm). Spore formation was not observed. The strain grew optimally at 37 °C (range for growth was 25-40 °C) and pH 7.0 (pH 6.0-7.5), and could grow fermentatively on yeast extract, glucose, ribose, xylose, malate, tryptone, pyruvate, fumarate, Casamino acids, serine and cysteine. The main end-products of glucose fermentation were acetate and hydrogen. In co-culture with the hydrogenotrophic methanogen Methanospirillum hungatei DSM 864(T), strain 7WAY-8-7(T) could utilize lactate, glycerol, ethanol, 1-propanol, 1-butanol, l-glutamate, alanine, leucine, isoleucine, valine, histidine, asparagine, glutamine, arginine, lysine, threonine, 2-oxoglutarate, aspartate and methionine. A Stickland reaction was not observed with some pairs of amino acids. Yeast extract was required for growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite and Fe (III) were not used as terminal electron acceptors. The G+C content of the genomic DNA was 61.4 mol%. 16S rRNA gene sequence analysis revealed that the isolate belongs to the uncultured environmental clone clade (called 'PD-UASB-13' in the Greengenes database) in the bacterial phylum Synergistetes, showing less than 90?% sequence similarity with closely related described species such as Aminivibrio pyruvatiphilus and Aminobacterium colombiense (89.7?% and 88.7?%, respectively). The major cellular fatty acids were iso-C13?:?0, iso-C15?:?0, anteiso-C15?:?0, C18?:?1, C19?:?1, C20?:?1 and C21?:?1. A novel genus and species, Lactivibrio alcoholicus gen. nov., sp. nov. is proposed to accommodate strain 7WAY-8-7(T) (?=?JCM 17151(T)?=?DSM 24196(T)?=?CGMCC 1.5159(T)). PMID:24676730

Qiu, Yan-Ling; Hanada, Satoshi; Kamagata, Yoichi; Guo, Rong-Bo; Sekiguchi, Yuji

2014-06-01

294

Growth of the protozoan parasite Entamoeba histolytica in 5-azacytidine has limited effects on parasite gene expression  

PubMed Central

Background In higher eukaryotes DNA methylation regulates important biological functions including silencing of gene expression and protection from adverse effects of retrotransposons. In the protozoan parasite Entamoeba histolytica, a DNA methyltransferase has been identified and treatment with 5-azacytidine (5-AzaC), a potent inhibitor of DNA methyltransferase, has been reported to attenuate parasite virulence. However, the overall extent of DNA methylation and its subsequent effects on global gene expression in this parasite are currently unknown. Results In order to identify the genome-wide effects of DNA methylation in E. histolytica, we used a short oligonucleotide microarray representing 9,435 genes (~95% of all annotated amebic genes) and compared the expression profile of E. histolytica HM-1:IMSS parasites with those treated with 23 ?M 5-AzaC for up to one week. Overall, 2.1% of genes tested were transcriptionally modulated under these conditions. 68 genes were upregulated and 131 genes down regulated (2-fold change; p-value < 0.05). Sodium-bisulfite treatment and sequencing of genes indicated that there were at least two subsets of genes with genomic DNA methylation in E. histolytica: (i) genes that were endogenously silenced by genomic DNA methylation and for which 5-AzaC treatment induced transcriptional de-repression, and (ii) genes that have genomic DNA methylation, but which were not endogenously silenced by the methylation. We identified among the genes down regulated by 5-AzaC treatment a cysteine proteinase (2.m00545) and lysozyme (52.m00148) both of which have known roles in amebic pathogenesis. Decreased expression of these genes in the 5-AzaC treated E. histolytica may account in part for the parasites reduced cytolytic abilities. Conclusion This work represents the first genome-wide analysis of DNA-methylation in Entamoeba histolytica and indicates that DNA methylation has relatively limited effects on gene expression in this parasite.

Ali, Ibne Karim M; Ehrenkaufer, Gretchen M; Hackney, Jason A; Singh, Upinder

2007-01-01

295

Amplified fragment length polymorphism: an adept technique for genome mapping, genetic differentiation, and intraspecific variation in protozoan parasites.  

PubMed

With the advent of polymerase chain reaction (PCR), genetic markers are now accessible for all organisms, including parasites. Amplified fragment length polymorphism (AFLP) is a PCR-based marker for the rapid screening of genetic diversity and intraspecific variation. It is a potent fingerprinting technique for genomic DNAs of any origin or complexity and rapidly generates a number of highly replicable markers that allow high-resolution genotyping. AFLPs are convenient and reliable in comparison to other markers like random amplified polymorphic DNA, restriction fragment length polymorphism, and simple sequence repeat in terms of time and cost efficiency, reproducibility, and resolution as it does not require template DNA sequencing. In addition, AFLP essentially probes the entire genome at random, without prior sequence knowledge. So, AFLP markers have emerged as an advance type of genetic marker with broad application in genomic mapping, population genetics, and DNA fingerprinting and are ideally suited as screening tool for molecular markers linked with biological and clinical traits. This review describes the AFLP procedure and its applications and overview in the fingerprinting of a genome, which has been currently used in parasite genome research. We outline the AFLP procedure adapted for Leishmania genome study and discuss the benefits of AFLPs for assessing genetic variation and genome mapping over other existing molecular techniques. We highlight the possible use of AFLPs as genetic markers with its broad application in parasitological research because it allows random screening of the entire genome for linkage with genetic and clinical properties of the parasite. In this review, we have taken a pragmatic approach on the study of AFLP for genome mapping and polymorphism in protozoan parasites and conclude that AFLP is a very useful tool. PMID:23254590

Kumar, Awanish; Misra, Pragya; Dube, Anuradha

2013-02-01

296

Quantitative assessment of the proliferation of the protozoan parasite Perkinsus marinus using a bioluminescence assay for ATP content  

PubMed Central

Perkinsus marinus is a protozoan parasite that causes “Dermo” disease in the eastern oyster Crasssostrea virginica in coastal areas of the USA. Until now, intervention strategies against the parasite have found limited success, and Dermo still remains one of the main hurdles for the restoration of oyster populations. We adapted a commercial adenosine tri-phosphate (ATP) content-based assay to assess the in vitro proliferation of P. marinus in a 96-well plate format, and validated the method by measuring the effects of potential anti-proliferative compounds. The sensitivity (1.5–3.1 × 104 cells/well), linearity (R2 = 0.983), and signal stability (60 min) support the reliability of the assay for assessing cell proliferation. Validation of the assay by culturing P. marinus in the presence of increasing concentrations of triclosan showed a dose–response profile. The IC50 value obtained was higher than that reported earlier, possibly due to the use of different viability assay methods and a different P. marinus strain. The antibiotics G418 and tetracycline and the herbicide fluridone were active against P. marinus proliferation; the IC50 of chloramphenicol, ciprofloxacin, and atrazine was relatively high suggesting either off-target effects or inability to reach the targets. The validation of the ATP-based assay, together with significant advantages of the Perkinsus culture methodology (homogeneity, reproducibility, and high cell densities), underscores the value of this assay for developing high-throughput screens for the identification of novel leader compounds against Perkinsus species, and most importantly, for the closely-related apicomplexan parasites.

Shridhar, Surekha; Hassan, Kolaleh; Sullivan, David J.; Vasta, Gerardo R.; Fernandez Robledo, Jose A.

2013-01-01

297

The potential for marine bivalve shellfish to act as transmission vehicles for outbreaks of protozoan infections in humans: a review.  

PubMed

Most marine molluscan bivalve shellfish feed on suspended phytoplankton which are trapped from water pumped across the gills by ciliary action. Pathogenic microorganisms in the water may be filtered by the gills during feeding, and become concentrated in the digestive glands/tract. If these pathogens are not excreted or inactivated by the shellfish, or in subsequent preparatory processes, they may be ingested by consumers, the shellfish thereby acting as vehicles of infection. The protozoan parasites Cryptosporidium spp., Giardia duodenalis and Toxoplasma gondii have the potential to be transmitted in this way, and here we review the accumulating knowledge on the occurrence and survival of the transmission stages of these parasites in shellfish, whilst also emphasising the considerable gaps in our knowledge. Relevant information is particularly lacking for T. gondii, which, in comparison with Cryptosporidium spp. and G. duodenalis, has been relatively under-researched in this context. Although it seems evident that these shellfish can accumulate and concentrate all three of these parasites from the surrounding water, whether Giardia cysts remain viable and infectious is unknown, and some evidence suggests that they may be inactivated by the shellfish. Although both Toxoplasma and Cryptosporidium apparently retain their infectivity for prolonged periods in shellfish, the actual public health threat posed by these parasites via these shellfish is unclear, largely because there is minimal evidence of infection transmission. Reasons for this apparent lack of infection transmission are discussed and it is recommended that the potential for transmission via shellfish consumption is recognised by those concerned with investigating transmission of these infections. PMID:17928081

Robertson, L J

2007-12-15

298

Molecular and phylogenetic characterization of honey bee viruses, Nosema microsporidia, protozoan parasites, and parasitic mites in China.  

PubMed

China has the largest number of managed honey bee colonies, which produce the highest quantity of honey and royal jelly in the world; however, the presence of honey bee pathogens and parasites has never been rigorously identified in Chinese apiaries. We thus conducted a molecular survey of honey bee RNA viruses, Nosema microsporidia, protozoan parasites, and tracheal mites associated with nonnative Apis mellifera ligustica and native Apis cerana cerana colonies in China. We found the presence of black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV), but not that of acute bee paralysis virus (ABPV) or Kashmir bee virus (KBV). DWV was the most prevalent in the tested samples. Phylogenies of Chinese viral isolates demonstrated that genetically heterogeneous populations of BQCV, CBPV, DWV, and A. cerana-infecting SBV, and relatively homogenous populations of IAPV and A. meliifera-infecting new strain of SBV with single origins, are spread in Chinese apiaries. Similar to previous observations in many countries, Nosema ceranae, but not Nosema apis, was prevalent in the tested samples. Crithidia mellificae, but not Apicystis bombi was found in five samples, including one A. c. cerana colony, demonstrating that C. mellificae is capable of infecting multiple honey bee species. Based on kinetoplast-encoded cytochrome b sequences, the C. mellificae isolate from A. c. cerana represents a novel haplotype with 19 nucleotide differences from the Chinese and Japanese isolates from A. m. ligustica. This suggests that A. c. cerana is the native host for this specific haplotype. The tracheal mite, Acarapis woodi, was detected in one A. m. ligustica colony. Our results demonstrate that honey bee RNA viruses, N. ceranae, C. mellificae, and tracheal mites are present in Chinese apiaries, and some might be originated from native Asian honey bees. PMID:23467539

Yang, Bu; Peng, Guangda; Li, Tianbang; Kadowaki, Tatsuhiko

2013-02-01

299

IgG antibody responses in mice coinfected with Toxocara canis and other helminths or protozoan parasites.  

PubMed

The immune response expressed by IgG antibodies in BALB/c mice experimentally infected with Toxocara canis, was studied with the aim of verifying the possible in vivo cross-reactivity between antigens of T. canis and other parasites (Ascaris suum, Taenia crassiceps, Schistosoma mansoni, Strongyloides venezuelensis and Toxoplasma gondii). Experiments included three groups of mice: one infected only by T. canis, another with one of the other species of parasites and a third concomitantly infected with T. canis and the other species in question. Animals were bled by orbital plexus at 23, 38 and 70 days post infection (p.i.). Sera were analyzed for anti-Toxocara antibodies by ELISA and Immunoblotting, using excretion-secretion antigens (ES), obtained from culture of third-stage larvae of T. canis. For all experiments a control group comprised by ten non-infected mice was used. Only in the case of A. suum infection, in these experimental conditions, the occurrence of cross-reactivity with T. canis was observed. However, in the case of co-infection of T. canis - S. mansoni, T. canis - S. venezuelensis and T. canis - T. crassiceps the production of anti-Toxocara antibodies was found at levels significantly lower than those found in mice infected with T. canis only. Co-infection with S. mansoni or S. venezuelensis showed lower mortality rates compared to what occurred in the animals with single infections. Results obtained in mice infected with T. canis and T. gondii showed significant differences between the mean levels of the optical densities of animals infected with T. canis and concomitantly infected with the protozoan only in the 23rd day p.i. PMID:22634886

Lescano, Susana A Zevallos; Nakhle, Maria Cristina; Ribeiro, Manoel Carlos S A; Chieffi, Pedro Paulo

2012-01-01

300

Incidence and persistence of zoonotic bacterial and protozoan pathogens in a beef cattle feedlot runoff control vegetative treatment system.  

PubMed

Determining the survival of zoonotic pathogens in livestock manure and runoff is critical for understanding the environmental and public health risks associated with these wastes. The occurrence and persistence of the bacterial pathogens Escherichia coli O157:H7 and Campylobacter spp. in a passive beef cattle feedlot runoff control-vegetative treatment system were examined over a 26-mo period. Incidence of the protozoans Cryptosporidium spp. and Giardia spp. was also assessed. The control system utilizes a shallow basin to collect liquid runoff and accumulate eroded solids from the pen surfaces; when an adequate liquid volume is attained, the liquid is discharged from the basin onto a 4.5-ha vegetative treatment area (VTA) of bromegrass which is harvested as hay. Basin discharge transported E. coli O157, Campylobacter spp., and generic E. coli into the VTA soil, but without additional discharge from the basin, the pathogen prevalences decreased over time. Similarly, the VTA soil concentrations of generic E. coli initially decreased rapidly, but lower residual populations persisted. Isolation of Cryptosporidium oocysts and Giardia cysts from VTA samples was infrequent, indicating differences in sedimentation and/or transport in comparison to bacteria. Isolation of generic E. coli from freshly cut hay from VTA regions that received basin discharge (12 of 30 vs. 1 of 30 control samples) provided evidence for the risk of contamination; however, neither E. coli O157 or Campylobacter spp. were recovered from the hay following baling. This work indicates that the runoff control system is effective for reducing environmental risk by containing and removing pathogens from feedlot runoff. PMID:17965390

Berry, Elaine D; Woodbury, Bryan L; Nienaber, John A; Eigenberg, Roger A; Thurston, Jeanette A; Wells, James E

2007-01-01

301

A Genome-Wide Over-Expression Screen Identifies Genes Involved in Phagocytosis in the Human Protozoan Parasite, Entamoeba histolytica  

PubMed Central

Functional genomics and forward genetics seek to assign function to all known genes in a genome. Entamoeba histolytica is a protozoan parasite for which forward genetics approaches have not been extensively applied. It is the causative agent of amoebic dysentery and liver abscess, and infection is prevalent in developing countries that cannot prevent its fecal-oral spread. It is responsible for considerable global morbidity and mortality. Given that the E. histolytica genome has been sequenced, it should be possible to apply genomic approaches to discover gene function. We used a genome-wide over-expression screen to uncover genes regulating an important virulence function of E. histolytica, namely phagocytosis. We developed an episomal E. histolytica cDNA over-expression library, transfected the collection of plasmids into trophozoites, and applied a high-throughput screen to identify phagocytosis mutants in the population of over-expressing cells. The screen was based on the phagocytic uptake of human red blood cells loaded with the metabolic toxin, tubercidin. Expression plasmids were isolated from trophozoites that survived exposure to tubercidin-charged erythrocytes (phagocytosis mutants), and the cDNAs were sequenced. We isolated the gene encoding profilin, a well-characterized cytoskeleton-regulating protein with a known role in phagocytosis. This supports the validity of our approach. Furthermore, we assigned a phagocytic role to several genes not previously known to function in this manner. To our knowledge, this is the first genome-wide forward genetics screen to be applied to this pathogen. The study demonstrates the power of forward genetics in revealing genes regulating virulence in E. histolytica. In addition, the study validates an E. histolytica cDNA over-expression library as a valuable tool for functional genomics.

King, Ada V.; Welter, Brenda H.; Koushik, Amrita B.; Gordon, Lindsay N.; Temesvari, Lesly A.

2012-01-01

302

Novel Transmembrane Receptor Involved in Phagosome Transport of Lysozymes and ?-Hexosaminidase in the Enteric Protozoan Entamoeba histolytica  

PubMed Central

Lysozymes and hexosaminidases are ubiquitous hydrolases in bacteria and eukaryotes. In phagocytic lower eukaryotes and professional phagocytes from higher eukaryotes, they are involved in the degradation of ingested bacteria in phagosomes. In Entamoeba histolytica, which is the intestinal protozoan parasite that causes amoebiasis, phagocytosis plays a pivotal role in the nutrient acquisition and the evasion from the host defense systems. While the content of phagosomes and biochemical and physiological roles of the major phagosomal proteins have been established in E. histolytica, the mechanisms of trafficking of these phagosomal proteins, in general, remain largely unknown. In this study, we identified and characterized for the first time the putative receptor/carrier involved in the transport of the above-mentioned hydrolases to phagosomes. We have shown that the receptor, designated as cysteine protease binding protein family 8 (CPBF8), is localized in lysosomes and mediates transport of lysozymes and ?-hexosaminidase ?-subunit to phagosomes when the amoeba ingests mammalian cells or Gram-positive bacillus Clostridium perfringens. We have also shown that the binding of CPBF8 to the cargos is mediated by the serine-rich domain, more specifically three serine residues of the domain, which likely contains trifluoroacetic acid-sensitive O-phosphodiester-linked glycan modifications, of CPBF8. We further showed that the repression of CPBF8 by gene silencing reduced the lysozyme and ?-hexosaminidase activity in phagosomes and delayed the degradation of C. perfringens. Repression of CPBF8 also resulted in decrease in the cytopathy against the mammalian cells, suggesting that CPBF8 may also be involved in, besides the degradation of ingested bacteria, the pathogenesis against the mammalian hosts. This work represents the first case of the identification of a transport receptor of hydrolytic enzymes responsible for the degradation of microorganisms in phagosomes.

Furukawa, Atsushi; Nakada-Tsukui, Kumiko; Nozaki, Tomoyoshi

2012-01-01

303

Role of predation by zooplankton in transport and fate of protozoan (oo)cysts in granular activated carbon filtration.  

PubMed

The significance of zooplankton in the transport and fate of pathogenic organisms in drinking water is poorly understood, although many hints of the role of predation in the persistence of microorganisms through water treatment processes can be found in literature. The objective of this study was to assess the impact of predation by natural zooplankton on the transport and fate of protozoan (oo)cysts in granular activated carbon (GAC) filtration process. UV-irradiated unlabelled Cryptosporidium parvum and Giardia lamblia (oo)cysts were seeded into two pilot-scale GAC filtration columns operated under full-scale conditions. In a two-week period after seeding, a reduction of free (oo)cysts retained in the filter bed was observed. Zooplankton was isolated from the filter bed and effluent water on a 30 microm net before and during the two-week period after seeding; it was enumerated and identified. Rotifers, which are potential predators of (oo)cysts, accounted for the major part of the isolated zooplankton. Analytical methods were developed to detect (oo)cysts internalized in natural zooplankton isolated from the filter bed and effluent water. Sample sonication was optimized to disrupt zooplankton organisms and release internalized microorganisms. (Oo)cysts released from zooplankton after sonication were isolated by IMS and stained (EasyStain) for microscopic counting. Both Cryptosporidium and Giardia (oo)cysts were detected in association with zooplankton in the filter bed samples as well as in the effluent of GAC filters. The results of this study suggest that predation by zooplankton can play a role in the remobilization of persistent pathogens such as Cryptosporidium and Giardia (oo)cysts retained in GAC filter beds, and consequently in the transmission of these pathogens in drinking water. PMID:19853879

Bichai, Françoise; Barbeau, Benoit; Dullemont, Yolanda; Hijnen, Wim

2010-02-01

304

A Highly Organized Structure Mediating Nuclear Localization of a Myb2 Transcription Factor in the Protozoan Parasite Trichomonas vaginalis ? †  

PubMed Central

Nuclear proteins usually contain specific peptide sequences, referred to as nuclear localization signals (NLSs), for nuclear import. These signals remain unexplored in the protozoan pathogen, Trichomonas vaginalis. The nuclear import of a Myb2 transcription factor was studied here using immunodetection of a hemagglutinin-tagged Myb2 overexpressed in the parasite. The tagged Myb2 was localized to the nucleus as punctate signals. With mutations of its polybasic sequences, 48KKQK51 and 61KR62, Myb2 was localized to the nucleus, but the signal was diffusive. When fused to a C-terminal non-nuclear protein, the Myb2 sequence spanning amino acid (aa) residues 48 to 143, which is embedded within the R2R3 DNA-binding domain (aa 40 to 156), was essential and sufficient for efficient nuclear import of a bacterial tetracycline repressor (TetR), and yet the transport efficiency was reduced with an additional fusion of a firefly luciferase to TetR, while classical NLSs from the simian virus 40 T-antigen had no function in this assay system. Myb2 nuclear import and DNA-binding activity were substantially perturbed with mutation of a conserved isoleucine (I74) in helix 2 to proline that altered secondary structure and ternary folding of the R2R3 domain. Disruption of DNA-binding activity alone by point mutation of a lysine residue, K51, preceding the structural domain had little effect on Myb2 nuclear localization, suggesting that nuclear translocation of Myb2, which requires an ordered structural domain, is independent of its DNA binding activity. These findings provide useful information for testing whether myriad Mybs in the parasite use a common module to regulate nuclear import.

Chu, Chien-Hsin; Chang, Lung-Chun; Hsu, Hong-Ming; Wei, Shu-Yi; Liu, Hsing-Wei; Lee, Yu; Kuo, Chung-Chi; Indra, Dharmu; Chen, Chinpan; Ong, Shiou-Jeng; Tai, Jung-Hsiang

2011-01-01

305

A novel protein phosphatase 2A (PP2A) is involved in the transformation of human protozoan parasite Trypanosoma cruzi.  

PubMed Central

Here we provide evidence for a critical role of PP2As (protein phosphatase 2As) in the transformation of Trypanosoma cruzi. In axenic medium at pH 5.0, trypomastigotes rapidly transform into amastigotes, a process blocked by okadaic acid, a potent PP2A inhibitor, at concentrations as low as 0.1 microM. 1-Norokadaone, an inactive okadaic acid analogue, did not affect the transformation. Electron microscopy studies indicated that okadaic acid-treated trypomastigotes had not undergone ultrastructural modifications, reinforcing the idea that PP2A inhibits transformation. Using a microcystin-Sepharose affinity column we purified the native T. cruzi PP2A. The enzyme displayed activity against 32P-labelled phosphorylase a that was inhibited in a dose-dependent manner by okadaic acid. The protein was also submitted to MS and, from the peptides obtained, degenerate primers were used to clone a novel T. cruzi PP2A enzyme by PCR. The isolated gene encodes a protein of 303 amino acids, termed TcPP2A, which displayed a high degree of homology (86%) with the catalytic subunit of Trypanosoma brucei PP2A. Northern-blot analysis revealed the presence of a major 2.1-kb mRNA hybridizing in all T. cruzi developmental stages. Southern-blot analysis suggested that the TcPP2A gene is present in low copy number in the T. cruzi genome. These results are consistent with the mapping of PP2A genes in two chromosomal bands by pulsed-field gel electrophoresis and chromoblot hybridization. Our studies suggest that in T. cruzi PP2A is important for the complete transformation of trypomastigotes into amastigotes during the life cycle of this protozoan parasite.

Gonzalez, Jorge; Cornejo, Alberto; Santos, Marcia R M; Cordero, Esteban M; Gutierrez, Bessy; Porcile, Patricio; Mortara, Renato A; Sagua, Hernan; Da Silveira, Jose Franco; Araya, Jorge E

2003-01-01

306

Protein substrates of a novel secretion system are numerous in the Bacteroidetes phylum and have in common a cleavable C-terminal secretion signal, extensive post-translational modification, and cell-surface attachment.  

PubMed

The secretion of certain proteins in Porphyromonas gingivalis is dependent on a C-terminal domain (CTD). After secretion, the CTD is cleaved prior to extensive modification of the mature protein, probably with lipopolysaccharide, therefore enabling attachment to the cell surface. In this study, bioinformatic analyses of the CTD demonstrated the presence of three conserved sequence motifs. These motifs were used to construct Hidden Markov Models (HMMs) that predicted 663 CTD-containing proteins in 21 fully sequenced species of the Bacteroidetes phylum, while no CTD-containing proteins were predicted in species outside this phylum. Further HMM searching of Cytophaga hutchinsonii led to a total of 171 predicted CTD proteins in that organism alone. Proteomic analyses of membrane fractions and culture fluid derived from P. gingivalis and four other species containing predicted CTDs (Parabacteroides distasonis, Prevotella intermedia, Tannerella forsythia, and C. hutchinsonii) demonstrated that membrane localization, extensive post-translational modification, and CTD-cleavage were conserved features of the secretion system. The CTD cleavage site of 10 different proteins from 3 different species was determined and found to be similar to the cleavage site previously determined in P. gingivalis, suggesting that homologues of the C-terminal signal peptidase (PG0026) are responsible for the cleavage in these species. PMID:24007199

Veith, Paul D; Nor Muhammad, Nor A; Dashper, Stuart G; Liki?, Vladimir A; Gorasia, Dhana G; Chen, Dina; Byrne, Samantha J; Catmull, Deanne V; Reynolds, Eric C

2013-10-01

307

Modification of activities of the ruminal ecosystem and its bacterial and protozoan composition during repeated dietary changes in cows.  

PubMed

Dietary change alters the ruminal ecosystem and can be regarded as a disturbance. Studying the response to a disturbance can help us understand the behavior of the ecosystem. Our work is concerned with the response of the ruminal ecosystem (composition and activities) during the application of repeated dietary disturbances to 6 dry Holstein cows. For 2 mo, the cows received a hay-based diet [experimental period (EP) 0], followed by 3 EP of successive changes (EP 1, 2, and 3) comprised of 2 parts: the first (10 d) with a corn silage-based diet and the second (25 d) with a hay-based diet. The measurements and samplings were done on the last days of EP 0 and of each part of EP 1 through 3, with the results of EP 0 used as covariables in the statistical models. The physicochemical measurements (pH and redox potential) and the fermentation variables (VFA, ammonia) were determined hourly between the morning and evening meals (n = 8 measurements/d). Samples of ruminal contents were taken 3 h after the morning meal to determine enzymatic activity [amylase, carboxymethyl cellulase (CMCase), and xylanase], to count the main protozoan genera and to quantify the bacteria by quantitative PCR, and to determine its structure by the capillary electrophoresis single-strand conformation polymorphism process. The pH fell for the corn silage-based diet with the EP (P < 0.05) but not for the hay-based diet. The VFA concentration decreased for both diets with the EP (P < 0.001), with the primary changes in acetate and propionate. The ammonia concentration increased for the corn silage-based diet with the EP (P < 0.05), whereas for the hay-based diet the highest value was observed for EP 2 (P < 0.05). The total quantity of bacteria decreased between EP 1 and 3 (P < 0.05) for both diets. The structure of the bacterial community was not affected by the disturbances for the corn silage-based diet, whereas for the hay-based diet large differences were evident between EP 1 and 3 (P < 0.05) and 2 and 3 (P < 0.01). The number of protozoa increased over the EP, with a more marked effect for the corn silage-based diet (diet × EP interaction, P < 0.05). The specific amylase, CMCase, and xylanase activities decreased over the EP for both diets (P < 0.05). The dietary changes applied in our experiment involved strong modifications of the ruminal ecosystem and alterations of ruminal fermentation and enzymatic activities. These alterations were reinforced with the repetition of the dietary changes. PMID:22952372

Monteils, V; Rey, M; Silberberg, M; Cauquil, L; Combes, S

2012-12-01

308

High-resolution genotyping and mapping of recombination and gene conversion in the protozoan Theileria parva using whole genome sequencing  

PubMed Central

Background Theileria parva is a tick-borne protozoan parasite, which causes East Coast Fever, a disease of cattle in sub-Saharan Africa. Like Plasmodium falciparum, the parasite undergoes a transient diploid life-cycle stage in the gut of the arthropod vector, which involves an obligate sexual cycle. As assessed using low-resolution VNTR markers, the crossover (CO) rate in T. parva is relatively high and has been reported to vary across different regions of the genome; non-crossovers (NCOs) and CO-associated gene conversions have not yet been characterised due to the lack of informative markers. To examine all recombination events at high marker resolution, we sequenced the haploid genomes of two parental strains, and two recombinant clones derived from ticks fed on cattle that had been simultaneously co-infected with two different parasite isolates. Results By comparing the genome sequences, we were able to genotype over 64 thousand SNP markers with an average spacing of 127 bp in the two progeny clones. Previously unrecognized COs in sub-telomeric regions were detected. About 50% of CO breakpoints were accompanied by gene conversion events. Such a high fraction of COs accompanied by gene conversions demonstrated the contributions of meiotic recombination to the diversity and evolutionary success of T. parva, as the process not only redistributed existing genetic variations, but also altered allelic frequencies. Compared to COs, NCOs were more frequently observed and more uniformly distributed across the genome. In both progeny clones, genomic regions with more SNP markers had a reduced frequency of COs or NCOs, suggesting that the sequence divergence between the parental strains was high enough to adversely affect recombination frequencies. Intra-species polymorphism analysis identified 81 loci as likely to be under selection in the sequenced genomes. Conclusions Using whole genome sequencing of two recombinant clones and their parents, we generated maps of COs, NCOs, and CO-associated gene conversion events for T. parva. The data comprises one of the highest-resolution genome-wide analyses of the multiple outcomes of meiotic recombination for this pathogen. The study also demonstrates the usefulness of high throughput sequencing typing for detailed analysis of recombination in organisms in which conventional genetic analysis is technically difficult.

2012-01-01

309

Prevalence of a protozoan parasite Cristigera sp. (Ciliophora:Ciliatea) from edible oysters (Mollusca:Bivalvia) of Sundarbans, West Bengal, India.  

PubMed

The coastal region of West Bengal is bestowed with a wide range of natural forest and aquatic resources. The estuarine complex is a culmination of the interaction of land, sea and freshwater. It offers diverse specialised habitats such as mangroves, non vegetated mudflats, inter tidal zones and reclaimed areas. Such areas are home to a number of terrestrial, freshwater and marine communities. Edible oyster resources in these regions are Crassostrea gryphoides and Saccostrea cucullata, which are the keystone species found in the intertidal zone and can tolerate huge variation of salinity. These are used as food by local people and marketed to earn cash. The population of this species has been declined due to parasitic infection and pollution. There are many protozoan parasites which infect these oysters causing diseases. During survey period, a protozoan parasite of the genus Cristigera have been observed only from the edible oyster Crassostrea gryphoides collected from Kaikhali and Frasergunj among three selected sites namely Kaikhali, Frasergunj and Digha of West Bengal mainly during monsoon and post-monsoon season. Considering such rare and specific prevalence of Cristigera sp, it may be considered as potential bio-indicator. PMID:25035589

Biswas, Tanima; Bandyopadhyay, Probir Kumar

2014-09-01

310

Application of a qPCR assay with melting curve analysis for detection and differentiation of protozoan oocysts in human fecal samples from Dominican Republic.  

PubMed

A quantitative polymerase chain reaction assay with melt curve analysis (qPCR-MCA) was applied for the detection of protozoan oocysts in 501 human fecal samples collected in Dominican Republic. Samples were subjected to qPCR using universal coccidia primers targeting 18S rDNA to detect oocysts followed by MCA to identify oocyst species based on amplicon melting temperature. Putative positive samples were also tested by conventional PCR and microscopy. Cystoisospora belli (×3), Cryptosporidium parvum (×3), Cryptosporidium hominis (×5), Cryptosporidium meleagridis (×1), Cryptosporidium canis (×1), and Cyclospora cayetanensis (×9) were detected by qPCR-MCA and confirmed by sequencing. This assay consistently detected 10 copies of the cloned target fragment and can be considered more efficient and sensitive than microscopy flotation methods for detecting multiple species of oocysts in human feces. The qPCR-MCA is a reliable protozoan oocyst screening assay for use on clinical and environmental samples in public health, food safety and veterinary programs. PMID:24019437

Lalonde, Laura F; Reyes, Julissa; Gajadhar, Alvin A

2013-11-01

311

Effect of aeration on pollutants removal, biofilm activity and protozoan abundance in conventional and hybrid horizontal subsurface-flow constructed wetlands.  

PubMed

The large area demand of constructed wetlands (CWs) is documented as a weak point that can be potentially reduced by applying active aeration. The aim of this study was, therefore, to understand the effects of aeration on the treatment performance, the biofilm activity, the protozoan population size and potential CW footprint reduction of different horizontal flow (HF) CW configurations. Two experimental periods were considered: a first period with low organic loading rate (OLR) and a second period with high OLR. Three HF CW configurations were compared: a conventional (control), an aerated and a hybrid CW (aerated followed by a non-aerated CW). The results obtained reinforced the competence of aerated CW for organic matter removal (81-89% of chemical oxygen demand) while for nitrogen elimination the control (19-24%) and hybrid (8-41%) systems performed better than the aerated system (-6% to 33%). Biofilm activity and protozoa abundance were distinctly higher at the inlet zones when compared with the outlet zones of all CWs, as well as in the aerated systems when compared with the non-aerated CWs. The protozoan abundance increased with an increase in the OLR and ciliates were found to be the dominant group. Overall, the active aeration highlighted the efficiency and stability of the CWs for organic matter removal and thus can be used as a promising tool to enhance microbial activity and grazing by protozoa; eventually reducing solid accumulation in the bed media. These beneficial effects contribute to reduce the CWs' area requirements. PMID:24956803

Zapater-Pereyra, M; Gashugi, E; Rousseau, D P L; Alam, M R; Bayansan, T; Lens, P N L

2014-08-01

312

Pontibacter actiniarum gen. nov., sp. nov., a novel member of the phylum 'Bacteroidetes', and proposal of Reichenbachiella gen. nov. as a replacement for the illegitimate prokaryotic generic name Reichenbachia Nedashkovskaya et al. 2003.  

PubMed

The taxonomic position of a marine, gliding, pink-pigmented, aerobic, heterotrophic and Gram-negative bacterium was established using a polyphasic approach. 16S rRNA gene sequence analysis indicated that the strain was a member of the phylum 'Bacteroidetes' in which it occupied a separate lineage. The predominant cellular fatty acids were C15 : 0 iso, C17 : 0 iso 3-OH, summed feature 3 and summed feature 4. The DNA G+C content was 48.7 mol%. Phylogenetic evidence and the results of phenotypic, genotypic and chemotaxonomic analyses strongly support the assignment of the newly isolated bacterium as a member of a novel genus and species, for which the name Pontibacter actiniarum gen. nov., sp. nov. is proposed. The type strain is KMM 6156T (=KCTC 12367T=LMG 23027T). It is also proposed that the illegitimate names Reichenbachia and Reichenbachia agariperforans are replaced with Reichenbachiella and Reichenbachiella agariperforans, respectively. PMID:16280531

Nedashkovskaya, Olga I; Kim, Seung Bum; Suzuki, Makoto; Shevchenko, Lyudmila S; Lee, Myung Sook; Lee, Kang Hyun; Park, Myung Soo; Frolova, Galina M; Oh, Hyun Woo; Bae, Kyung Sook; Park, Ho-Yong; Mikhailov, Valery V

2005-11-01

313

Chthonomonas calidirosea gen. nov., sp. nov., an aerobic, pigmented, thermophilic micro-organism of a novel bacterial class, Chthonomonadetes classis nov., of the newly described phylum Armatimonadetes originally designated candidate division OP10.  

PubMed

An aerobic, saccharolytic, obligately thermophilic, motile, non-spore-forming bacterium, strain T49(T), was isolated from geothermally heated soil at Hell's Gate, Tikitere, New Zealand. On the basis of 16S rRNA gene sequence similarity, T49(T) is the first representative of a new class in the newly described phylum Armatimonadetes, formerly known as candidate division OP10. Cells of strain T49(T) stained Gram-negative and were catalase-positive and oxidase-negative. Cells possessed a highly corrugated outer membrane. The major fatty acids were 16?:?0, i17?:?0 and ai17?:?0. The G+C content of the genomic DNA was 54.6 mol%. Strain T49(T) grew at 50-73 °C with an optimum temperature of 68 °C, and at pH 4.7-5.8 with an optimum growth pH of 5.3. A growth rate of 0.012 h(-1) was observed under optimal temperature and pH conditions. The primary respiratory quinone was MK-8. Optimal growth was achieved in the absence of NaCl, although growth was observed at NaCl concentrations as high as 2?% (w/v). Strain T49(T) was able to utilize mono- and disaccharides such as cellobiose, lactose, mannose and glucose, as well as branched or amorphous polysaccharides such as starch, CM-cellulose, xylan and glycogen, but not highly linear polysaccharides such as crystalline cellulose or cotton. On the basis of its phylogenetic position and phenotypic characteristics, we propose that strain T49(T) represents a novel bacterial genus and species within the new class Chthonomonadetes classis nov. of the phylum Armatimonadetes. The type strain of Chthonomonas calidirosea gen. nov., sp. nov. is T49(T) (?=?DSM 23976(T)?=?ICMP 18418(T)). PMID:21097641

Lee, Kevin C-Y; Dunfield, Peter F; Morgan, Xochitl C; Crowe, Michelle A; Houghton, Karen M; Vyssotski, Mikhail; Ryan, Jason L J; Lagutin, Kirill; McDonald, Ian R; Stott, Matthew B

2011-10-01

314

Rubritalea spongiae sp. nov. and Rubritalea tangerina sp. nov., two carotenoid- and squalene-producing marine bacteria of the family Verrucomicrobiaceae within the phylum 'Verrucomicrobia', isolated from marine animals.  

PubMed

Two Gram-negative, non-motile, coccoid or rod-shaped, chemoheterotrophic bacteria designated strains YM21-132(T) and YM27-005(T) were isolated from marine animals, and were subjected to a polyphasic taxonomic examination. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the two isolates belong to the genus Rubritalea of the phylum 'Verrucomicrobia' (subdivision 1). The novel isolates shared approximately 97-98 % sequence similarity with each other and showed 93-97 % similarity with Rubritalea species of the family Verrucomicrobiaceae. The level of DNA-DNA relatedness between strains YM21-132(T) and YM27-005(T) was less than 70 %, which is accepted as the phylogenetic definition of a species. Both strains produced reddish carotenoid pigments and squalene. The cell wall peptidoglycan of both strains contained muramic acid and meso-diaminopimelic acid. The G+C contents of the genomic DNA were 48.0 mol% (strain YM21-132(T)) and 50.3 mol% (strain YM27-005(T)). The presence of MK-8 and MK-9 as the major isoprenoid quinones, and iso-C(14 : 0), iso-C(16 : 0) and C(16 : 1)omega7c as the major cellular fatty acids supported the identification of the two novel strains as members of the genus Rubritalea. On the basis of polyphasic taxonomic studies, it was concluded that these strains should be classified as representing two novel, separate species in the genus Rubritalea within the phylum 'Verrucomicrobia', for which the names Rubritalea spongiae sp. nov. (type strain YM21-132(T)=MBIC08281(T)=KCTC 12906(T)) and Rubritalea tangerina sp. nov. (type strain YM27-005(T)=MBIC08282(T)=KCTC 12907(T)) are proposed. PMID:17911307

Yoon, Jaewoo; Matsuo, Yoshihide; Matsuda, Satoru; Adachi, Kyoko; Kasai, Hiroaki; Yokota, Akira

2007-10-01

315

DNA from Protozoan Parasites Babesia bovis, Trypanosoma cruzi, and T. brucei Is Mitogenic for B Lymphocytes and Stimulates Macrophage Expression of Interleukin12, Tumor Necrosis Factor Alpha, and Nitric Oxide  

Microsoft Academic Search

The activation of innate immune responses by genomic DNA from bacteria and several nonvertebrate organisms represents a novel mechanism of pathogen recognition. We recently demonstrated the CpG- dependent mitogenic activity of DNA from the protozoan parasite Babesia bovis for bovine B lymphocytes (W. C. Brown, D. M. Estes, S. E. Chantler, K. A. Kegerreis, and C. E. Suarez, Infect. Immun.

LISL K. M. SHODA; KIMBERLY A. KEGERREIS; CARLOS E. SUAREZ; ISABEL RODITI; RICARDO S. CORRAL; GUSTAVO M. BERTOT; JUNZO NORIMINE; WENDY C. BROWN

2001-01-01

316

Re-circulation of lymphocytes mediated by sphingosine-1-phosphate receptor-1 contributes to resistance against experimental infection with the protozoan parasite Trypanosoma cruzi.  

PubMed

T-cell mediated immune responses are critical for acquired immunity against infection by the intracellular protozoan parasite Trypanosoma cruzi. Despite its importance, it is currently unknown where protective T cells are primed and whether they need to re-circulate in order to exert their anti-parasitic effector functions. Here, we show that after subcutaneous challenge, CD11c(+)-dependent specific CD8(+) T-cell immune response to immunodominant parasite epitopes arises almost simultaneously in the draining lymph node (LN) and the spleen. However, until day 10 after infection, we observed a clear upregulation of activation markers only on the surface of CD11C(+)PDCA1(+) cells present in the LN and not in the spleen. Therefore, we hypothesized that CD8(+) T cells re-circulated rapidly from the LN to the spleen. We investigated this phenomenon by administering FTY720 to T. cruzi-infected mice to prevent egress of T cells from the LN by interfering specifically with signalling through sphingosine-1-phosphate receptor-1. In T. cruzi-infected mice receiving FTY720, CD8 T-cell immune responses were higher in the draining LN and significantly reduced in their spleen. Most importantly, FTY720 increased susceptibility to infection, as indicated by elevated parasitemia and accelerated mortality. Similarly, administration of FTY720 to mice genetically vaccinated with an immunodominant parasite antigen significantly reduced their protective immunity, as observed by the parasitemia and survival of vaccinated mice. We concluded that re-circulation of lymphocytes mediated by sphingosine-1-phosphate receptor-1 greatly contributes to acquired and vaccine-induced protective immunity against experimental infection with a human protozoan parasite. PMID:22381075

Dominguez, Mariana R; Ersching, Jonatan; Lemos, Ramon; Machado, Alexandre V; Bruna-Romero, Oscar; Rodrigues, Mauricio M; de Vasconcelos, José Ronnie C

2012-04-16

317

Experimental infection of embryonated eggs of chicken with Besnoitia caprae.  

PubMed

Knowledge on parasites of the genus Besnoitia, especially Besnoitia caprae, is sparse. Besnoitia caprae, an obligate intracellular protozoan parasite belonging to the phylum Apicomplexa, is the causative agent of caprine besnoitiosis. This experiment was conducted to determine the infectivity of the bradyzoites and the resultant histopathological lesions after inoculation of B. caprae bradyzoites in the embryonated egg. Eight groups, each having six embryonated eggs, were assigned in this experiment. Seven groups were inoculated with different doses of B. caprae bradyzoite inoculums (1x10(3), 1x10(4), 1x10(5), 1x10(6), 5x10(6), 1x10(7) and 2x10(7)) via the allantoic cavity route. The 8th group was considered as control. The embryos inoculated with higher doses showed mortality between 14 and 21 days of incubation (5-12 days post-infection). Those embryos that received lower doses were hatched on day 21 of incubation; however, they presented loss of feathers and paralysis and showed hyperemia in the skin of the feet regions. Histopathological sections of the skin revealed the presence of hemorrhages, hyperemia and inflammatory responses. Some of the chickens were euthanized after 50 days postinfection (DPI) and histopathological examination of their tissues revealed haemorrhages and coagulative necrosis with the presence of mononuclear cells infiltration in the liver and heart with interstitial pneumonia. It seems that the embryonated eggs could be a useful model to study the parasite's biology. PMID:21399581

Namazi, F; Oryan, A; Namavari, M M; Rahimain, A

2010-12-01

318

Isolation of Besnoitia besnoiti from infected cattle in Portugal.  

PubMed

Besnoitia besnoiti, an obligate intracellular protozoan parasite belonging to the phylum apicomplexa, is the causative agent of bovine besnoitiosis. Besnoitiosis is responsible for significant losses in the cattle industry of Africa and Mediterranean countries due to the high morbidity rate, abortion and infertility in males. The acute stage of disease is associated with the proliferative forms (tachyzoites) and is characterized by fever, whimpery, general weakness and swelling of the superficial lymph nodes. During the following chronic stage, a huge number of cysts are formed mainly in the subcutaneous tissues. This process is non-reversible, and chronic besnoitiosis is characterized by hyper-sclerodermia, hyperkeratosis, alopecia and, in bulls, atrophy, sclerosis and focal necrosis that cause irreversible lesions in the testis. In this paper we report on the identification of large cysts in the skin of a cow and a bull in Portugal, which presented loss of hair and enlargement and pachydermis all over the body. The observation of a two-layered cyst wall within the host cell, the encapsulation of the host cell by a large outer cyst wall, and the subcutaneous localization of the cysts within the host, were characteristic for B. besnoiti. The parasites were isolated from the infected animals and successfully propagated in Vero cells without prior passages in laboratory animals. Morphological characterization of B. besnoiti tachyzoites and the amplification of the 149 bp segment from the internal transcribed spacer 1 (ITS1), aided with specific primers, confirmed the identification of B. besnoiti. PMID:16822614

Cortes, H C E; Reis, Y; Waap, H; Vidal, R; Soares, H; Marques, I; Pereira da Fonseca, I; Fazendeiro, I; Ferreira, M L; Caeiro, V; Shkap, V; Hemphill, A; Leitão, A

2006-11-01

319

Species concepts and malaria parasites: detecting a cryptic species of Plasmodium.  

PubMed Central

Species of malaria parasite (phylum Apicomplexa: genus Plasmodium) have traditionally been described using the similarity species concept (based primarily on differences in morphological or life-history characteristics). The biological species concept (reproductive isolation) and phylogenetic species concept (based on monophyly) have not been used before in defining species of Plasmodium. Plasmodium azurophilum, described from Anolis lizards in the eastern Caribbean, is actually a two-species cryptic complex. The parasites were studied from eight islands, from Puerto Rico in the north to Grenada in the south. Morphology of the two species is very similar (differences are indistinguishable to the eye), but one infects only erythrocytes and the other only white blood cells. Molecular data for the cytochrome b gene reveal that the two forms are reproductively isolated; distinct haplotypes are present on each island and are never shared between the erythrocyte-infecting and leucocyte-infecting species. Each forms a monophyletic lineage indicating that they diverged before becoming established in the anoles of the eastern Caribbean. This comparison of the similarity, biological and phylogenetic species concepts for malaria parasites reveals the limited value of using only similarity measures in defining protozoan species.

Perkins, S L

2000-01-01

320

The cell biology of secondary endosymbiosis--how parasites build, divide and segregate the apicoplast.  

PubMed

Protozoan parasites of the phylum Apicomplexa harbour a chloroplast-like organelle, the apicoplast. The biosynthetic pathways localized to this organelle are of cyanobacterial origin and therefore offer attractive targets for the development of new drugs for the treatment of malaria and toxoplasmosis. The apicoplast also provides a unique system to study the cell biology of endosymbiosis. This organelle is the product of secondary endosymbiosis, the marriage of an alga and an auxotrophic eukaryote. This origin has led to a fascinating set of novel cellular mechanisms that are clearly distinct from those employed by the plant chloroplast. Here we explore how the apicoplast interacts with its 'host' to secure building blocks for its biogenesis and how the organelle is divided and segregated during mitosis. Considerable advances in parasite genetics and genomics have transformed apicomplexans, long considered hard to study, into highly tractable model organisms. We discuss how these resources might be marshalled to develop a detailed mechanistic picture of apicoplast cell biology. PMID:16968220

Vaishnava, Shipra; Striepen, Boris

2006-09-01

321

Structure and Function of a G-actin Sequestering Protein with a Vital Role in Malaria Oocyst Development inside the Mosquito Vector*  

PubMed Central

Cyclase-associated proteins (CAPs) are evolutionary conserved G-actin-binding proteins that regulate microfilament turnover. CAPs have a modular structure consisting of an N-terminal adenylate cyclase binding domain, a central proline-rich segment, and a C-terminal actin binding domain. Protozoan parasites of the phylum Apicomplexa, such as Cryptosporidium and the malaria parasite Plasmodium, express small CAP orthologs with homology to the C-terminal actin binding domain (C-CAP). Here, we demonstrate by reverse genetics that C-CAP is dispensable for the pathogenic Plasmodium blood stages. However, c-cap(-) parasites display a complete defect in oocyst development in the insect vector. By trans-species complementation we show that the Cryptosporidium parvum ortholog complements the Plasmodium gene functions. Purified recombinant C. parvum C-CAP protein binds actin monomers and prevents actin polymerization. The crystal structure of C. parvum C-CAP shows two monomers with a right-handed ?-helical fold intercalated at their C termini to form the putative physiological dimer. Our results reveal a specific vital role for an apicomplexan G-actin-binding protein during sporogony, the parasite replication phase that precedes formation of malaria transmission stages. This study also exemplifies how Plasmodium reverse genetics combined with biochemical and structural analyses of orthologous proteins can offer a fast track toward systematic gene characterization in apicomplexan parasites.

Hliscs, Marion; Sattler, Julia M.; Tempel, Wolfram; Artz, Jennifer D.; Dong, Aiping; Hui, Raymond; Matuschewski, Kai; Schuler, Herwig

2010-01-01

322

Composite genome map and recombination parameters derived from three archetypal lineages of Toxoplasma gondii  

PubMed Central

Toxoplasma gondii is a highly successful protozoan parasite in the phylum Apicomplexa, which contains numerous animal and human pathogens. T.gondii is amenable to cellular, biochemical, molecular and genetic studies, making it a model for the biology of this important group of parasites. To facilitate forward genetic analysis, we have developed a high-resolution genetic linkage map for T.gondii. The genetic map was used to assemble the scaffolds from a 10X shotgun whole genome sequence, thus defining 14 chromosomes with markers spaced at ?300 kb intervals across the genome. Fourteen chromosomes were identified comprising a total genetic size of ?592 cM and an average map unit of ?104 kb/cM. Analysis of the genetic parameters in T.gondii revealed a high frequency of closely adjacent, apparent double crossover events that may represent gene conversions. In addition, we detected large regions of genetic homogeneity among the archetypal clonal lineages, reflecting the relatively few genetic outbreeding events that have occurred since their recent origin. Despite these unusual features, linkage analysis proved to be effective in mapping the loci determining several drug resistances. The resulting genome map provides a framework for analysis of complex traits such as virulence and transmission, and for comparative population genetic studies.

Khan, Asis; Taylor, Sonya; Su, Chunlei; Mackey, Aaron J.; Boyle, Jon; Cole, Robert; Glover, Darius; Tang, Keliang; Paulsen, Ian T.; Berriman, Matt; Boothroyd, John C.; Pfefferkorn, Elmer R.; Dubey, J. P.; Ajioka, James W.; Roos, David S.; Wootton, John C.; Sibley, L. David

2005-01-01

323

Structural Evidence for Actin-like Filaments in Toxoplasma gondii Using High-Resolution Low-Voltage Field Emission Scanning Electron Microscopy  

NASA Astrophysics Data System (ADS)

The protozoan parasite Toxoplasma gondii is representative of a large group of parasites within the phylum Apicomplexa, which share a highly unusual motility system that is crucial for locomotion and active host cell invasion. Despite the importance of motility in the pathology of these unicellular organisms, the motor mechanisms for locomotion remain uncertain, largely because only limited data exist about composition and organization of the cytoskeleton. By using cytoskeleton stabilizing protocols on membrane-extracted parasites and novel imaging with high-resolution low-voltage field emission scanning electron microscopy (LVFESEM), we were able to visualize for the first time a network of actin-sized filaments just below the cell membrane. A complex cytoskeletal network remained after removing the actin-sized fibers with cytochalasin D, revealing longitudinally arranged, subpellicular microtubules and intermediate-sized fibers of 10 nm, which, in stereo images, are seen both above and below the microtubules. These approaches open new possibilities to characterize more fully the largely unexplored and unconventional cytoskeletal motility complex in apicomplexan parasites.

Schatten, Heide; Sibley, L. David; Ris, Hans

2003-08-01

324

Evidence for the shikimate pathway in apicomplexan parasites  

Microsoft Academic Search

Parasites of the phylum Apicomplexa cause substantial morbidity, mortality and economic losses, and new medicines to treat them are needed urgently,. The shikimate pathway is an attractive target for herbicides and antimicrobial agents because it is essential in algae, higher plants, bacteria and fungi, but absent from mammals,. Here we present biochemical, genetic and chemotherapeutic evidence for the presence of

Fiona Roberts; Craig W. Roberts; Jennifer J. Johnson; Dennis E. Kyle; Tino Krell; John R. Coggins; Graham H. Coombs; Wilbur K. Milhous; Saul Tzipori; David J. P. Ferguson; Debopam Chakrabarti; Rima McLeod

1998-01-01

325

Epigenomic Modifications Predict Active Promoters and Gene Structure in Toxoplasma gondii  

Microsoft Academic Search

Mechanisms of gene regulation are poorly understood in Apicomplexa, a phylum that encompasses deadly human pathogens like Plasmodium and Toxoplasma. Initial studies suggest that epigenetic phenomena, including histone modifications and chromatin remodeling, have a profound effect upon gene expression and expression of virulence traits. Using the model organism Toxoplasma gondii, we characterized the epigenetic organization and transcription patterns of a

Mathieu Gissot; Krystyna A Kelly; James W Ajioka; John M Greally; Kami Kim

2007-01-01

326

Functional Characterization of a Redundant Plasmodium TRAP Family Invasin, TRAP-Like Protein, by Aldolase Binding and a Genetic Complementation Test  

Microsoft Academic Search

Efficient and specific host cell entry is of exquisite importance for intracellular pathogens. Parasites of the phylum Apicomplexa are highly motile and actively enter host cells. These functions are mediated by type I transmembrane invasins of the TRAP family that link an extracellular recognition event to the parasite actin-myosin motor machinery. We systematically tested potential parasite invasins for binding to

Kirsten Heiss; Hui Nie; Sumit Kumar; Thomas M. Daly; Lawrence W. Bergman; Kai Matuschewski

2008-01-01

327

Chemotherapy against babesiosis  

Microsoft Academic Search

Babesiosis is caused by a haemotropic protozoal parasite of the genus Babesia, member of the phylum Apicomplexa and transmitted by the bite of an infected tick. There are many Babesia species affecting livestock, dogs, horses and rodents which are of economic significance. Infections can occur without producing symptoms, but babesiosis may also be severe and sometimes fatal caused by the

Henri J. Vial; A. Gorenflot

2006-01-01

328

Zoonotic babesiosis: Overview of the disease and novel aspects of pathogen identity  

Microsoft Academic Search

Babesiosis is a zoonosis caused by tick-transmitted intraerythrocytic protozoa of the Phylum Apicomplexa. The disease mostly occurs in the USA, but cases have also been reported in several European countries, in Egypt, India, Japan, Korea, Taiwan, and South Africa. The main pathological event is lysis of erythrocytes resulting in haemolytic anaemia, which in severe cases may lead to organ failure

Jeremy Gray; Annetta Zintl; Anke Hildebrandt; Klaus-Peter Hunfeld; Louis Weiss

2010-01-01

329

Cytokine and chemokine responses to helminth and protozoan parasites and to fungus and mite allergens in neonates, children, adults, and the elderly  

PubMed Central

Background In rural sub-Saharan Africa, endemic populations are often infected concurrently with several intestinal and intravascular helminth and protozoan parasites. A specific, balanced and, to an extent, protective immunity will develop over time in response to repeated parasite encounters, with immune responses initially being poorly adapted and non-protective. The cellular production of pro-inflammatory and regulatory cytokines and chemokines in response to helminth, protozoan antigens and ubiquitous allergens were studied in neonates, children, adults and the elderly. Results In children schistosomiasis prevailed (33%) while hookworm and Entamoeba histolytica/E. dispar was found in up to half of adults and the elderly. Mansonella perstans filariasis was only present in adults (24%) and the elderly (25%). Two or more parasite infections were diagnosed in 41% of children, while such polyparasitism was present in 34% and 38% of adults and the elderly. Cytokine and chemokine production was distinctively inducible by parasite antigens; pro-inflammatory Th2-type cytokine IL-19 was activated by Entamoeba and Ascaris antigens, being low in neonates and children while IL-19 production enhanced “stepwise” in adults and elderly. In contrast, highest production of MIP-1delta/CCL15 was present in neonates and children and inducible by Entamoeba-specific antigens only. Adults and the elderly had enhanced regulatory IL-27 cytokine responses, with Th2-type chemokines (MCP-4/CCL13, Eotaxin-2/CCL24) and cytokines (IL-33) being notably inducible by helminth- and Entamoeba-specific antigens and fungus-derived allergens. The lower cellular responsiveness in neonates and children highlighted the development of a parasite-specific cellular response profile in response to repeated episodes of exposure and re-infection. Conclusions Following repeated exposure to parasites, and as a consequence of host inability to prevent or eliminate intestinal helminth or protozoa infections, a repertoire of immune responses will evolve with lessened pro-inflammatory and pronounced regulatory cytokines and chemokines; this is required for partial parasite control as well as for preventing inadequate and excessive host tissue and organ damage.

2013-01-01

330

Current Therapeutics, Their Problems, and Sulfur-Containing-Amino-Acid Metabolism as a Novel Target against Infections by "Amitochondriate" Protozoan Parasites  

PubMed Central

The “amitochondriate” protozoan parasites of humans Entamoeba histolytica, Giardia intestinalis, and Trichomonas vaginalis share many biochemical features, e.g., energy and amino acid metabolism, a spectrum of drugs for their treatment, and the occurrence of drug resistance. These parasites possess metabolic pathways that are divergent from those of their mammalian hosts and are often considered to be good targets for drug development. Sulfur-containing-amino-acid metabolism represents one such divergent metabolic pathway, namely, the cysteine biosynthetic pathway and methionine ?-lyase-mediated catabolism of sulfur-containing amino acids, which are present in T. vaginalis and E. histolytica but absent in G. intestinalis. These pathways are potentially exploitable for development of drugs against amoebiasis and trichomoniasis. For instance, l-trifluoromethionine, which is catalyzed by methionine ?-lyase and produces a toxic product, is effective against T. vaginalis and E. histolytica parasites in vitro and in vivo and may represent a good lead compound. In this review, we summarize the biology of these microaerophilic parasites, their clinical manifestation and epidemiology of disease, chemotherapeutics, the modes of action of representative drugs, and problems related to these drugs, including drug resistance. We further discuss our approach to exploit unique sulfur-containing-amino-acid metabolism, focusing on development of drugs against E. histolytica.

Ali, Vahab; Nozaki, Tomoyoshi

2007-01-01

331

An assessment of the use of drug and non-drug interventions in the treatment of Ichthyophthirius multifiliis Fouquet, 1876, a protozoan parasite of freshwater fish.  

PubMed

Infection by the ciliate protozoan Ichthyophthirius multifiliis Fouquet, 1876 causes significant economic losses in freshwater aquaculture worldwide. Following the ban on the use of malachite green for treating food fish, there has been extensive research aimed at identifying suitable replacements. In this paper we critically assess drug and non-drug interventions, which have been tested for use or have been employed against this parasite and evaluate possibilities for their application in farm systems. Current treatments include the administration of formaldehyde, sodium chloride (salt), copper sulphate and potassium permanganate. However, purportedly more environmentally friendly drugs such as humic acid, potassium ferrate (VI), bronopol and the peracetic acid-based products have recently been tested and represent promising alternatives. Further investigation, is required to optimize the treatments and to establish precise protocols in order to minimize the quantity of drug employed whilst ensuring the most efficacious performance. At the same time, there needs to be a greater emphasis placed on the non-drug aspects of management strategies, including the use of non-chemical interventions focusing on the removal of free-swimming stages and tomocysts of I. multifiliis from farm culture systems. Use of such strategies provides the hope of more environmentally friendly alternatives for the control of I. multifiliis infections. PMID:22078025

Picón-Camacho, S M; Marcos-Lopez, M; Bron, J E; Shinn, A P

2012-02-01

332

Patterns of host-parasite adaptation in three populations of monarch butterflies infected with a naturally occurring protozoan disease: virulence, resistance, and tolerance.  

PubMed

Many studies have used host-parasite systems to study local adaptation, but few of these studies have found unequivocal evidence for adaptation. One potential reason is that most studies have focused on limited measures of host and parasite fitness that are generally assumed to be under negative frequency-dependent selection. We have used reciprocal cross-infection experiments to test for local adaptation in Hawaiian, south Floridian, and eastern North American populations of monarch butterflies and their protozoan parasites. Sympatric host-parasite combinations did not result in greater host or parasite fitness, as would be expected under coevolutionary dynamics driven by negative frequency-dependent selection. Instead, we found that Hawaiian hosts were more resistant and carried more infective and virulent parasites, which is consistent with theoretical predictions for virulence evolution and coevolutionary arms race dynamics. We also found that Hawaiian hosts were more tolerant, particularly of Hawaiian parasites, indicating that increased resistance does not preclude increased tolerance within a population and that hosts may be more tolerant of local parasites. We did not find a similar pattern in the south Floridian or eastern populations, possibly because host-parasite adaptation occurs within the context of a greater ecological community. PMID:24231547

Sternberg, Eleanore D; Li, Hui; Wang, Rebecca; Gowler, Camden; de Roode, Jacobus C

2013-12-01

333

Two distinct populations of Bovine IL-17(+) T-cells can be induced and WC1(+)IL-17(+)?? T-cells are effective killers of protozoan parasites.  

PubMed

IL-17 has emerged as a key player in the immune system, exhibiting roles in protection from infectious diseases and promoting inflammation in autoimmunity. Initially thought to be CD4 T-cell-derived, the sources of IL-17 are now known to be varied and belong to both the innate and adaptive arms of the immune system. Mechanisms for inducing IL-17 production in lymphoid cells are thought to rely on appropriate antigenic stimulation in the context of TGF-?1, IL-6 and/or IL-1?. Using culture protocols adapted from human studies, we have effectively induced both bovine CD4(+) and WC1(+) ?? T-cells to produce IL-17 termed Th17 and ??17 cells, respectively. The negative regulatory effect of IFN-? on mouse and human IL-17 production can be extended to the bovine model, as addition of IFN-? decreases IL-17 production in both cell types. Furthermore we show that infection with the protozoan Neospora caninum will induce fibroblasts to secrete pro-IL-17 factors thereby inducing a ??17 phenotype that preferentially kills infected target cells. Our study identifies two T-cell sources of IL-17, and is the first to demonstrate a protective effect of IL-17(+) T-cells in ruminants. Our findings offer further opportunities for future adjuvants or vaccines which could benefit from inducing these responses. PMID:24961164

Peckham, R K; Brill, R; Foster, D S; Bowen, A L; Leigh, J A; Coffey, T J; Flynn, R J

2014-01-01

334

Defective spontaneous but normal antibody-dependent cytotoxicity for an extracellular protozoan parasite, Giardia lamblia, by C3H/HeJ mouse macrophages.  

PubMed

To understand murine host responses to extracellular protozoa, the capacity of peritoneal macrophages to exhibit cytotoxicity for [3H]thymidine-labeled Giardia lamblia trophozoites was investigated. Resident peritoneal macrophages from C3H/HeN mice expressed spontaneous cytotoxicity for G. lamblia in a manner that was dependent on both time and effector cell number; this cytotoxic activity was increased with cells elicited by an intraperitoneal injection of thio-glycollate. In contrast, spontaneous cytotoxicity for G. lamblia by resident and thioglycollate-elicited peritoneal macrophages from C3H/HeJ mice was markedly reduced. In the presence of anti-G. lamblia serum (ADCC), however, peritoneal macrophages from both C3H/HeN and C3H/HeJ mice exhibited striking augmentation of their cytotoxic activity for G. lamblia to equivalent levels. We conclude that macrophages from C3H/HeJ mice express defective spontaneous cytotoxicity but normal ADCC for the extracellular protozoan parasite, G. lamblia. The dissociation between the expression of these two effector cell functions suggests that macrophage spontaneous cytotoxicity and ADCC for extracellular protozoa are mediated by separate macrophage functions. PMID:6713541

Smith, P D; Keister, D B; Wahl, S M; Meltzer, M S

1984-04-15

335

Expression of a truncated hepatitis E virus capsid protein in the protozoan organism Leishmania tarentolae and its application in a serological assay.  

PubMed

Zoonotic infections with hepatitis E virus (HEV) genotype 3 are presumably transmitted via contaminated pig meat products, which raises the necessity for enhanced serological surveillance of pig herds. The aim of the study was to set up a novel protein expression system to overcome the well-known problems in (HEV-) protein expression using the standard Escherichia coli tools such as inclusion body formation and loss of protein conformation. A recombinant strain of the protozoan organism Leishmania tarentolae (L. tarentolae) was therefore established. A fragment of HEV ORF2 coding for a truncated capsid protein of a porcine HEV strain was cloned and parts of the plasmid DNA were introduced into the Leishmania genome, resulting in stably transformed cells. Via a C-terminal His-tag the recombinant HEV?ORF2 protein could be purified and concentrated directly from the medium, resulting in a total protein amount of approximately 1.4 mg/l Leishmania culture. The recombinant protein was coated on ELISA plates and was proven to be highly reactive and well-suited to be applied in a serological assay. By investigating 144 porcine sera, the in-house assay detected specific antibodies in 43.1% of the samples and demonstrated a higher sensitivity than a commercially available antibody test. Taken together, it was shown that L. tarentolae exhibits a remarkable alternative expression strategy for viral antigens with considerable advantages of a eukaryotic protein expression host. PMID:23747546

Baechlein, C; Meemken, D; Pezzoni, G; Engemann, C; Grummer, B

2013-10-01

336

Some corrections of coccidian (Apicomplexa: Protozoa) nomenclature.  

PubMed

The following nomenclatural corrections and changes are introduced for the coccidia. NEW SPECIES: Cryptosporidium rhesi from the rhesus monkey Macaca mulatta; Cryptosporidium serpentis from the snakes Elaphe guttata, Elapha subocularis, Crotalus horridus, and Sanzinia madagascarensis; Eimeria perazae from the lizard Cnemidophorus l. lemniscatus; and Eimeria tarichae from the salamander Taricha toirosa. NEW COMBINATIONS: Orcheobius carinii for Cariniella carinii from the frog Leptodactylus ocellatus; Schellackia iguanae for Lainsonia iguanae from the iguana Iguana iguana; Schellackia weinbergi for Haemogregarina weinbergi from the lizard Tupinambis nigropunctatus; Dorisa harpia for Dorisiella harpia from the bat Harpiocephalus harpia lasyurus; Barrouxia labbei for Echinospora labbei from the centipedes Lithobius mutabilis and L. pyrenaicus; and Barrouxia ventricosa for Echinospora ventricosa from the centipede Lithobius hexodus. The generic names Lainsonia and Gordonella are synonymized with Schellackia; Echinospora with Barrouxia; and Cariniella with Orcheobius. PMID:7463253

Levine, N D

1980-10-01

337

CALYPTOSPORA FUNDULI (APICOMPLEXA): LIFE CYCLE AND TAXONOMY  

EPA Science Inventory

The taxonomic status of the extraintestinal piscine coccidium Calyptospora funduli is based in part on its requirement of an intermediate host (the daggerblade grass shrimp, Palaemonetes pugio). Grass shrimp fed livers of Gulf killifish (Fundulus grandis) infected with sporulated...

338

Characterization of the Fine Specificity of Bovine CD8 T-Cell Responses to Defined Antigens from the Protozoan Parasite Theileria parva?  

PubMed Central

Immunity against the bovine intracellular protozoan parasite Theileria parva has been shown to be mediated by CD8 T cells. Six antigens targeted by CD8 T cells from T. parva-immune cattle of different major histocompatibility complex (MHC) genotypes have been identified, raising the prospect of developing a subunit vaccine. To facilitate further dissection of the specificity of protective CD8 T-cell responses and to assist in the assessment of responses to vaccination, we set out to identify the epitopes recognized in these T. parva antigens and their MHC restriction elements. Nine epitopes in six T. parva antigens, together with their respective MHC restriction elements, were successfully identified. Five of the cytotoxic-T-lymphocyte epitopes were found to be restricted by products of previously described alleles, and four were restricted by four novel restriction elements. Analyses of CD8 T-cell responses to five of the epitopes in groups of cattle carrying the defined restriction elements and immunized with live parasites demonstrated that, with one exception, the epitopes were consistently recognized by animals of the respective genotypes. The analysis of responses was extended to animals immunized with multiple antigens delivered in separate vaccine constructs. Specific CD8 T-cell responses were detected in 19 of 24 immunized cattle. All responder cattle mounted responses specific for antigens for which they carried an identified restriction element. By contrast, only 8 of 19 responder cattle displayed a response to antigens for which they did not carry an identified restriction element. These data demonstrate that the identified antigens are inherently dominant in animals with the corresponding MHC genotypes.

Graham, Simon P.; Pelle, Roger; Yamage, Mat; Mwangi, Duncan M.; Honda, Yoshikazu; Mwakubambanya, Ramadhan S.; de Villiers, Etienne P.; Abuya, Evelyne; Awino, Elias; Gachanja, James; Mbwika, Ferdinand; Muthiani, Anthony M.; Muriuki, Cecelia; Nyanjui, John K.; Onono, Fredrick O.; Osaso, Julius; Riitho, Victor; Saya, Rosemary M.; Ellis, Shirley A.; McKeever, Declan J.; MacHugh, Niall D.; Gilbert, Sarah C.; Audonnet, Jean-Christophe; Morrison, W. Ivan; van der Bruggen, Pierre; Taracha, Evans L. N.

2008-01-01

339

A novel strategy for the identification of antigens that are recognised by bovine MHC class I restricted cytotoxic T cells in a protozoan infection using reverse vaccinology  

PubMed Central

Background Immunity against the bovine protozoan parasite Theileria parva has previously been shown to be mediated through lysis of parasite-infected cells by MHC class I restricted CD8+ cytotoxic T lymphocytes. It is hypothesized that identification of CTL target schizont antigens will aid the development of a sub-unit vaccine. We exploited the availability of the complete genome sequence data and bioinformatics tools to identify genes encoding secreted or membrane anchored proteins that may be processed and presented by the MHC class I molecules of infected cells to CTL. Results Of the 986 predicted open reading frames (ORFs) encoded by chromosome 1 of the T. parva genome, 55 were selected based on the presence of a signal peptide and/or a transmembrane helix domain. Thirty six selected ORFs were successfully cloned into a eukaryotic expression vector, transiently transfected into immortalized bovine skin fibroblasts and screened in vitro using T. parva-specific CTL. Recognition of gene products by CTL was assessed using an IFN-? ELISpot assay. A 525 base pair ORF encoding a 174 amino acid protein, designated Tp2, was identified by T. parva-specific CTL from 4 animals. These CTL recognized and lysed Tp2 transfected skin fibroblasts and recognized 4 distinct epitopes. Significantly, Tp2 specific CD8+ T cell responses were observed during the protective immune response against sporozoite challenge. Conclusion The identification of an antigen containing multiple CTL epitopes and its apparent immunodominance during a protective anti-parasite response makes Tp2 an attractive candidate for evaluation of its vaccine potential.

Graham, Simon P; Honda, Yoshikazu; Pelle, Roger; Mwangi, Duncan M; Glew, E Jane; de Villiers, Etienne P; Shah, Trushar; Bishop, Richard; van der Bruggen, Pierre; Nene, Vishvanath; Taracha, Evans LN

2007-01-01

340

Metabolome Analysis Revealed Increase in S-Methylcysteine and Phosphatidylisopropanolamine Synthesis upon l-Cysteine Deprivation in the Anaerobic Protozoan Parasite Entamoeba histolytica*  

PubMed Central

l-Cysteine is ubiquitous in all living organisms and is involved in a variety of functions, including the synthesis of iron-sulfur clusters and glutathione and the regulation of the structure, stability, and catalysis of proteins. In the protozoan parasite Entamoeba histolytica, the causative agent of amebiasis, l-cysteine plays an essential role in proliferation, adherence, and defense against oxidative stress; however, the essentiality of this amino acid in the pathways it regulates is not well understood. In the present study, we applied capillary electrophoresis time-of-flight mass spectrometry to quantitate charged metabolites modulated in response to l-cysteine deprivation in E. histolytica, which was selected as a model for examining the biological roles of l-cysteine. l-Cysteine deprivation had profound effects on glycolysis, amino acid, and phospholipid metabolism, with sharp decreases in the levels of l-cysteine, l-cystine, and S-adenosylmethionine and a dramatic accumulation of O-acetylserine and S-methylcysteine. We further demonstrated that S-methylcysteine is synthesized from methanethiol and O-acetylserine by cysteine synthase, which was previously considered to be involved in sulfur-assimilatory l-cysteine biosynthesis. In addition, l-cysteine depletion repressed glycolysis and energy generation, as it reduced acetyl-CoA, ethanol, and the major nucleotide di- and triphosphates, and led to the accumulation of glycolytic intermediates. Interestingly, l-cysteine depletion increased the synthesis of isopropanolamine and phosphatidylisopropanolamine, and it was confirmed that their increment was not a result of oxidative stress but was a specific response to l-cysteine depletion. We also identified a pathway in which isopropanolamine is synthesized from methylglyoxal via aminoacetone. To date, this study represents the first case where l-cysteine deprivation leads to drastic changes in core metabolic pathways, including energy, amino acid, and phospholipid metabolism.

Husain, Afzal; Sato, Dan; Jeelani, Ghulam; Mi-ichi, Fumika; Ali, Vahab; Suematsu, Makoto; Soga, Tomoyoshi; Nozaki, Tomoyoshi

2010-01-01

341

Occurrence of Collagen in the Phylum Mollusca  

Microsoft Academic Search

CONSIDERABLE interest has recently been shown in the occurrence of a collagen type of protein among the various invertebrate groups. X-ray diffraction1,2 studies have explored a wide range of examples, and more recently chemical investigations have used various chromatographic techniques to determine the composition of certain preparations3-5. Most of this work has been performed on tissues from single species bearing

S. C. Melnick

1958-01-01

342

Bacterial Protein Structures Reveal Phylum Dependent Divergence  

PubMed Central

Protein sequence space is vast compared to protein fold space. This raises important questions about how structures adapt to evolutionary changes in protein sequences. A growing trend is to regard protein fold space as a continuum rather than a series of discrete structures. From this perspective, homologous protein structures within the same functional classification should reveal a constant rate of structural drift relative to sequence changes. The clusters of orthologous groups (COG) classification system was used to annotate homologous bacterial protein structures in the Protein Data Bank (PDB). The structures and sequences of proteins within each COG were compared against each other to establish their relatedness. As expected, the analysis demonstrates a sharp structural divergence between the bacterial phyla Firmicutes and Proteobacteria. Additionally, each COG had a distinct sequence/structure relationship, indicating that different evolutionary pressures affect the degree of structural divergence. However, our analysis also shows the relative drift rate between sequence identity and structure divergence remains constant.

Shortridge, Matthew D.; Triplet, Thomas; Revesz, Peter; Griep, Mark A.; Powers, Robert

2011-01-01

343

Sarcocystis cernae : A parasite increasing the risk of predation of its intermediate host, Microtus arvalis  

Microsoft Academic Search

1)The transmission dynamics of the protozoan parasite Sarcocystis carnae (Cerná and Loucková 1976) (Apicomplexa, Eimeroidea, Sarcocystidae) in natural populations were studied in the Lauwersmeerpolder in the northern Netherlands. This parasite needs two hosts to complete its life cycle; the common vole (Microtus arvalis) as its intermediate host and the kestrel (Falco tinnunculus) which preys on the vole, as its final

I. Hoogenboom; C. Dijkstra

1987-01-01

344

Reprofiled drug targets ancient protozoans  

PubMed Central

Recently, we developed a novel automated, high throughput screening (HTS) methodology for the anaerobic intestinal parasite Entamoeba histolytica. We validated this HTS platform by screening a chemical library containing US Food and Drug Administration (FDA)-approved drugs and bioactive compounds. We identified an FDA-approved drug, auranofin, as most active against E. histolytica both in vitro and in vivo. Our cell culture and animal studies indicated that thioredoxin reductase, an enzyme involved in reactive oxygen species detoxification, was the target for auranofin in E. histolytica. Here, we discuss the rationale for drug development for three parasites which are major causes of diarrhea worldwide, E. histolytica, Giardia lamblia and Cryptosporidium parvum and extend our current finding of antiparasitic activity of auranofin to Entamoeba cysts, G. lamblia and C. parvum. These studies support the use of HTS assays and reprofiling FDA-approved drugs for new therapy for neglected tropical diseases.

Debnath, Anjan; Ndao, Momar; Reed, Sharon L.

2013-01-01

345

RNA interference in protozoan parasites  

Microsoft Academic Search

Summary RNA interference or RNAi is defined as the mecha- nism through which gene-specific, double-stranded RNA (dsRNA) triggers degradation of homologous transcripts. Besides providing an invaluable tool to downregulate gene expression in a variety of organ- isms, it is now evident that RNAi extends its tentacles into both the nucleus and the cytoplasm and is involved in a variety of

Elisabetta Ullu; Christian Tschudi; Tirtha Chakraborty

2004-01-01

346

Apo and calcium-bound crystal structures of cytoskeletal protein alpha-14 giardin (annexin E1) from the intestinal protozoan parasite Giardia lamblia.  

PubMed

Alpha-14 giardin (annexin E1), a member of the alpha giardin family of annexins, has been shown to localize to the flagella of the intestinal protozoan parasite Giardia lamblia. Alpha giardins show a common ancestry with the annexins, a family of proteins most of which bind to phospholipids and cellular membranes in a Ca(2+)-dependent manner and are implicated in numerous membrane-related processes including cytoskeletal rearrangements and membrane organization. It has been proposed that alpha-14 giardin may play a significant role during the cytoskeletal rearrangement during differentiation of Giardia. To gain a better understanding of alpha-14 giardin's mode of action and its biological role, we have determined the three-dimensional structure of alpha-14 giardin and its phospholipid-binding properties. Here, we report the apo crystal structure of alpha-14 giardin determined in two different crystal forms as well as the Ca(2+)-bound crystal structure of alpha-14 giardin, refined to 1.9, 1.6 and 1.65 A, respectively. Although the overall fold of alpha-14 giardin is similar to that of alpha-11 giardin, multiwavelength anomalous dispersion phasing was required to solve the alpha-14 giardin structure, indicating significant structural differences between these two members of the alpha giardin family. Unlike most annexin structures, which typically possess N-terminal domains, alpha-14 giardin is composed of only a core domain, followed by a C-terminal extension that may serve as a ligand for binding to cytoskeletal protein partners in Giardia. In the Ca(2+)-bound structure we detected five bound calcium ions, one of which is a novel, highly coordinated calcium-binding site not previously observed in annexin structures. This novel high-affinity calcium-binding site is composed of seven protein donor groups, a feature rarely observed in crystal structures. In addition, phospholipid-binding assays suggest that alpha-14 giardin exhibits calcium-dependent binding to phospholipids that coordinate cytoskeletal disassembly/assembly during differentiation of the parasite. PMID:19046974

Pathuri, Puja; Nguyen, Emily Tam; Ozorowski, Gabriel; Svärd, Staffan G; Luecke, Hartmut

2009-01-30

347

Comparative Genomics of the Apicomplexan Parasites Toxoplasma gondii and Neospora caninum: Coccidia Differing in Host Range and Transmission Strategy  

PubMed Central

Toxoplasma gondii is a zoonotic protozoan parasite which infects nearly one third of the human population and is found in an extraordinary range of vertebrate hosts. Its epidemiology depends heavily on horizontal transmission, especially between rodents and its definitive host, the cat. Neospora caninum is a recently discovered close relative of Toxoplasma, whose definitive host is the dog. Both species are tissue-dwelling Coccidia and members of the phylum Apicomplexa; they share many common features, but Neospora neither infects humans nor shares the same wide host range as Toxoplasma, rather it shows a striking preference for highly efficient vertical transmission in cattle. These species therefore provide a remarkable opportunity to investigate mechanisms of host restriction, transmission strategies, virulence and zoonotic potential. We sequenced the genome of N. caninum and transcriptomes of the invasive stage of both species, undertaking an extensive comparative genomics and transcriptomics analysis. We estimate that these organisms diverged from their common ancestor around 28 million years ago and find that both genomes and gene expression are remarkably conserved. However, in N. caninum we identified an unexpected expansion of surface antigen gene families and the divergence of secreted virulence factors, including rhoptry kinases. Specifically we show that the rhoptry kinase ROP18 is pseudogenised in N. caninum and that, as a possible consequence, Neospora is unable to phosphorylate host immunity-related GTPases, as Toxoplasma does. This defense strategy is thought to be key to virulence in Toxoplasma. We conclude that the ecological niches occupied by these species are influenced by a relatively small number of gene products which operate at the host-parasite interface and that the dominance of vertical transmission in N. caninum may be associated with the evolution of reduced virulence in this species.

Reid, Adam James; Vermont, Sarah J.; Cotton, James A.; Harris, David; Hill-Cawthorne, Grant A.; Konen-Waisman, Stephanie; Latham, Sophia M.; Mourier, Tobias; Norton, Rebecca; Quail, Michael A.; Sanders, Mandy; Shanmugam, Dhanasekaran; Sohal, Amandeep; Wasmuth, James D.; Brunk, Brian; Grigg, Michael E.; Howard, Jonathan C.; Parkinson, John; Roos, David S.; Trees, Alexander J.; Berriman, Matthew; Pain, Arnab; Wastling, Jonathan M.

2012-01-01

348

The parasite specific substitution matrices improve the annotation of apicomplexan proteins  

PubMed Central

Background A number of apicomplexan genomes have been sequenced successfully in recent years and this would help in understanding the biology of apicomplexan parasites. The members of the phylum Apicomplexa are important protozoan parasites (Plasmodium, Toxoplasma and Cryptosporidium etc) that cause some of the deadly diseases in humans and animals. In our earlier studies, we have shown that the standard BLOSUM matrices are not suitable for compositionally biased apicomplexan proteins. So we developed a novel series (SMAT and PfFSmat60) of substitution matrices which performed better in comparison to standard BLOSUM matrices and developed ApicoAlign, a sequence search and alignment tool for apicomplexan proteins. In this study, we demonstrate the higher specificity of these matrices and make an attempt to improve the annotation of apicomplexan kinases and proteases. Results The ROC curves proved that SMAT80 performs best for apicomplexan proteins followed by compositionally adjusted BLOSUM62 (PSI-BLAST searches), BLOSUM90 and BLOSUM62 matrices in terms of detecting true positives. The poor E-values and/or bit scores given by SMAT80 matrix for the experimentally identified coccidia-specific oocyst wall proteins against hematozoan (non-coccidian) parasites further supported the higher specificity of the same. SMAT80 uniquely detected (missed by BLOSUM) orthologs for 1374 apicomplexan hypothetical proteins against SwissProt database and predicted 70 kinases and 17 proteases. Further analysis confirmed the conservation of functional residues of kinase domain in one of the SMAT80 detected kinases. Similarly, one of the SMAT80 detected proteases was predicted to be a rhomboid protease. Conclusions The parasite specific substitution matrices have higher specificity for apicomplexan proteins and are helpful in detecting the orthologs missed by BLOSUM matrices and thereby improve the annotation of apicomplexan proteins which are hypothetical or with unknown function.

2012-01-01

349

DNA topoisomerases in apicomplexan parasites: promising targets for drug discovery  

PubMed Central

The phylum Apicomplexa includes a large group of protozoan parasites responsible for a wide range of animal and human diseases. Destructive pathogens, such as Plasmodium falciparum and Plasmodium vivax, causative agents of human malaria, Cryptosporidium parvum, responsible of childhood diarrhoea, and Toxoplasma gondii, responsible for miscarriages and abortions in humans, are frequently associated with HIV immunosuppression in AIDS patients. The lack of effective vaccines, along with years of increasing pressure to eradicate outbreaks with the use of drugs, has favoured the formation of multi-drug resistant strains in endemic areas. Almost all apicomplexan of medical interest contain two endosymbiotic organelles that contain their own mitochondrial and apicoplast DNA. Apicoplast is an attractive target for drug testing because in addition to harbouring singular metabolic pathways absent in the host, it also has its own transcription and translation machinery of bacterial origin. Accordingly, apicomplexan protozoa contain an interesting mixture of enzymes to unwind DNA from eukaryotic and prokaryotic origins. On the one hand, the main mechanism of DNA unwinding includes the scission of one—type I—or both DNA strands—type II eukaryotic topoisomerases, establishing transient covalent bonds with the scissile end. These enzymes are targeted by camptothecin and etoposide, respectively, two natural drugs whose semisynthetic derivatives are currently used in cancer chemotherapy. On the other hand, DNA gyrase is a bacterial-borne type II DNA topoisomerase that operates within the apicoplast and is effectively targeted by bacterial antibiotics like fluoroquinolones and aminocoumarins. The present review is an update on the new findings concerning topoisomerases in apicomplexan parasites and the role of these enzymes as targets for therapeutic agents.

Garcia-Estrada, Carlos; Prada, Christopher Fernandez; Fernandez-Rubio, Celia; Rojo-Vazquez, Francisco; Balana-Fouce, Rafael

2010-01-01

350

A Complex Small RNA Repertoire Is Generated by a Plant\\/Fungal-Like Machinery and Effected by a Metazoan-Like Argonaute in the Single-Cell Human Parasite Toxoplasma gondii  

Microsoft Academic Search

In RNA silencing, small RNAs produced by the RNase-III Dicer guide Argonaute-like proteins as part of RNA-induced silencing complexes (RISC) to regulate gene expression transcriptionally or post-transcriptionally. Here, we have characterized the RNA silencing machinery and exhaustive small RNAome of Toxoplasma gondii, member of the Apicomplexa, a phylum of animal- and human-infecting parasites that cause extensive health and economic damages

Laurence Braun; Dominique Cannella; Philippe Ortet; Mohamed Barakat; Céline F. Sautel; Sylvie Kieffer; Jérôme Garin; Olivier Bastien; Olivier Voinnet; Mohamed-Ali Hakimi

2010-01-01

351

Targeting to rhoptry organelles of Toxoplasma gondii involves evolutionarily conserved mechanisms  

Microsoft Academic Search

Intracellular parasites of the phylum Apicomplexa contain specialized rhoptry secretory organelles that have a crucial function in host-cell invasion and establishment of the parasitophorous vacuole. Here we show that localization of the Toxoplasma gondii rhoptry protein ROP2 is dependent on a YEQL sequence in the cytoplasmic tail that binds to µ-chain subunits of T. gondii and mammalian adaptors, and conforms

Heinrich C. Hoppe; Huân M. Ngô; Mei Yang; Keith A. Joiner

2000-01-01

352

Coccidian oöcysts as type-specimens: long-term storage in aqueous potassium dichromate solution preserves DNA  

Microsoft Academic Search

Preservation of the exogenous oöcyst stage of coccidian parasites (phylum Apicomplexa N.D. Levine, 1970) as type-specimens\\u000a of newly described species has long been problematical. Conventional fixatives have proved unsatisfactory, and compromises\\u000a such as embedding oöcysts in resin or photographing them are not entirely appropriate for various reasons. As an alternative,\\u000a chilled potassium dichromate solution (normally used in the laboratory to

R. B. Williams; P. Thebo; R. N. Marshall; J. A. Marshall

2010-01-01

353

Haemogregarina bigemina (Protozoa: Apicomplexa: Adeleorina)--past, present and future.  

PubMed

This paper reviews past, current and likely future research on the fish haemogregarine, Haemogregarina bigemina Laveran et Mesnil, 1901. Recorded from 96 species of fishes, across 70 genera and 34 families, this broad distribution for H. bigemina is questioned. In its type hosts and other fishes, the parasite undergoes intraerythrocytic binary fission, finally forming mature paired gamonts. An intraleukocytic phase is also reported, but not from the type hosts. This paper asks whether stages from the white cell series are truly H. bigemina. A future aim should be to compare the molecular constitution of so-called H. bigemina from a number of locations to determine whether all represent the same species. The transmission of H. bigemina between fishes is also considered. Past studies show that young fish acquire the haemogregarine when close to metamorphosis, but vertical and faecal-oral transmission seem unlikely. Some fish haemogregarines are leech-transmitted, but where fish populations with H. bigemina have been studied, these annelids are largely absent. However, haematophagous larval gnathiid isopods occur on such fishes and may be readily eaten by them. Sequential squashes of gnathiids from fishes with H. bigemina have demonstrated development of the haemogregarine in these isopods. Examination of histological sections through gnathiids is now underway to determine the precise development sites of the haemogregarine, particularly whether merozoites finally invade the salivary glands. To assist in this procedure and to clarify the internal anatomy of gnathiids, 3D visualisation of stacked, serial histological sections is being undertaken. Biological transmission experiments should follow these processes. PMID:15357389

Davies, Angela J; Smit, Nico J; Hayes, Polly M; Seddon, Alan M; Wertheim, David

2004-06-01

354

Prevalence of Eimeria macusaniensis (Apicomplexa: Eimeriidae) in midwestern Lama spp.  

PubMed

To compare the prevalence of Eimeria macusaniensis among midwestern llamas (Lama glama), alpacas (Lama pacos), and guanacos (Lama guanicoe), feces were obtained from Lama spp. in 10 states between October 1989 and February 1996. Feces were examined by centrifugal flotation in sugar solution (specific gravity--1.28-1.30), and oocysts were quantified by a modified McMaster method. Data were compared by host species and age classifications. Typical oocysts occurred in samples from 28% of 76 herds and 10.4% of 443 animals including 12% of 301 llamas, 7% of 115 alpacas, and 7.4% of 27 guanacos. Prevalence was significantly greater (P = 0.009) in animals < 1 yr of age in comparison to older animals for llams (22.1 v.s. 8.5%) and for all Lama spp. combined (17.1 vs. 8.4%). Fecal oocyst abundance was significantly greater (P = 0.001) in llamas < 1 yr of age in comparison to older llamas (30 vs. 16 oocysts per g of feces). Fecal oocyst intensities did not differ significantly. Prevalence in both age groups of midwestern llamas was greater than previously reported for llamas in the western United States. Prevalence in midwestern alpacas < 1 yr of age was lower than reported for alpacas of similar age in South America, but oocyst intensities were similar. These results indicate that infection with E. macusaniensis is more common in Lama spp. in North America than previously recognized. PMID:10219324

Jarvinen, J A

1999-04-01

355

Experimental infection of elaphid snakes with Cryptosporidium serpentis (Apicomplexa: Cryptosporidiidae).  

PubMed

The shedding pattern of fecal Cryptosporidium serpentis oocysts, histopathologic changes in the gastric region, and the effect of spiramycin treatment were investigated in 6 experimentally infected, captive black rat (Elaphe obsoleta obsoleta), 4 yellow rat (Elaphe obsoleta quadrivittata), and 2 corn snakes (Elaphe guttata guttata). Feces were monitored for up to 2 years postinfection (PI). No significant (P > 0.07) differences were observed between expected and observed numbers of PI oocyst-positive feces. Two of 5 control animals acquired natural infections of C. serpentis over the period of study. No morphological differences were observed between oocysts from experimental and natural infections. Clinical signs included postprandial regurgitation in 5 of 13 (38%) snakes, not coinciding with the shedding of fecal oocysts. Midbody swelling and self-cure were not observed. Spiramycin treatment of 4 of 12 experimentally infected animals resulted in negative fecal examinations in 2 snakes and reduced the percentage of oocyst-positive feces in 2 other snakes from 75.5% to 24.5% and from 83.9% to 33.6%. Biopsies and necropsies revealed stages of Cryptosporidium in the gastric mucosa of all spiramycin-treated animals. The gastric mucosa was thickened and edematous, with focal necrosis, mucosal petechiae, and brush hemorrhages. Fibroplasia of lamina propria associated with chronic mucosal inflammation were common. Examination of direct fecal smears was found not to be a reliable technique for diagnosis of cryptosporidial infections in snakes. PMID:7931919

Cranfield, M R; Graczyk, T K

1994-10-01

356

Proteases as Regulators of Pathogenesis: Examples from the Apicomplexa  

PubMed Central

The diverse functional roles that proteases play in basic biological processes make them essential for virtually all organisms. Not surprisingly, proteolysis is also a critical process required for many aspects of pathogenesis. In particular, obligate intracellular parasites must precisely coordinate proteolytic events during their highly regulated life cycle inside multiple host cell environments. Advances in chemical, proteomic and genetic tools that can be applied to parasite biology have led to an increased understanding of the complex events centrally regulated by proteases. In this review, we outline recent advances in our knowledge of specific proteolytic enzymes in two medically relevant apicomplexan parasites: Plasmodium falciparum and Toxoplasma gondii. Efforts over the last decade have begun to provide a map of key proteotolyic events that are essential for both parasite survival and propagation inside host cells. These advances in our molecular understanding of proteolytic events involved in parasite pathogenesis provide a foundation for the validation of new networks and enzyme targets that could be exploited for therapeutic purposes.

Li, Hao; Child, Matthew A.; Bogyo, Matthew

2011-01-01

357

HOST SPECIFICITY OF CALYPTOSPORA FUNDULI (APICOMPLEXA: CALYPOTOSPORIDAE) IN ATHERINOFORM FISHES  

EPA Science Inventory

Calyptospora funduli has a broad host specificity, infecting at least 7 natural and 10 additional experimental definitive hosts, all atheriniform fishes within 5 families, but most in the genus Fundulus. arriers, apparently innate ones, prevent any development of C. funduli in pe...

358

Phylogenetic analysis of the genus Hepatozoon Miller, 1908 (Apicomplexa: Adeleorina)  

Microsoft Academic Search

A phylogenetic analysis of species of Hepatozoon Miller, 1908 was performed using 16 morphological, morphometric and developmental characters. An adeleorin parasite of gastropod molluscs, Klossia helicina Schneider, 1875 and four haemogregarines of other genera, Karyolysus lacertae (Danilewsky, 1886), Cyrilia lignieresi (Laveran, 1906), Desseria myoxocephali (Fantham, Porter & Richardson, 1942) and Haemogregarina balli Paterson & Desser, 1976 were used as the

Todd G. Smith; Sherwin S. Desser

1997-01-01

359

Macronuclear Duplication in the Ciliated Protozoan Euplotes  

Microsoft Academic Search

The ribbon-like macronucleus of Euplotes euryslomus pinches in half ami- totically at each cell division. Several hours before the actual division two lightly staining duplication bands (reorganization bands) appear at the ends of the nu- cleus and approach each other slowly, finally meeting near the middle. Distal to the bands, that is, in regions through which the bands have already

JOSEPH G. GALL

1959-01-01

360

Protozoans Prefer Large and Metabolically Active Bacteria  

Microsoft Academic Search

The aim of our studies was to verify the hypothesis that heterotrophic nanoflagellates (HNF) prefer large and metabolically active bacterial cells, and avoid small and inactive bacteria. Determined graz- ing rates on bacteria differing in sizes and metabolic activity and observed changes in bacterioplankton structure in samples with and without bacterial grazers indicated that HNF prefer large (but not too

M. Koton-Czarnecka; R. J. Chróst

2003-01-01

361

Chromosomal localisation of five genes in Perkinsus olseni (Phylum Perkinsozoa).  

PubMed

The molecular karyotype of Perkinsus olseni, a pathogenic protist that infects the clam Ruditapes decussatus, comprises nine chromosomes, ranging in size from 0.15 Mb to 6.5 Mb, representing a haploid genome of about 28 Mb. In order to establish chromosome specific markers, PCR-amplified DNA sequences belonging to five conserved genes (18S rRNA, actin type I, hsp90, ?-tubulin and calmodulin) were hybridised to chromosomal bands separated by pulsed-field gel electrophoresis. Three of those probes (actin type I, hsp90 and calmodulin) hybridised to only one chromosome and the remaining two (18S rRNA and ?-tubulin) hybridised to two chromosomes. In the first place, the hybridisation pattern obtained serves to dispel any doubt about the nuclear location of the smallest chromosome observed in the molecular karyotype of Perkinsus olseni. Additionally, it will be a reference for further analysis of karyotype polymorphisms in the genus Perkinsus. PMID:22342132

Marques, Américo; Tato-Costa, Joana; Conde, Carlos; Azevedo, Carlos; Teles-Grilo, M Leonor

2012-08-01

362

Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida  

Microsoft Academic Search

Deuterostomes comprise vertebrates, the related invertebrate chordates (tunicates and cephalochordates) and three other invertebrate taxa: hemichordates, echinoderms and Xenoturbella. The relationships between invertebrate and vertebrate deuterostomes are clearly important for understanding our own distant origins. Recent phylogenetic studies of chordate classes and a sea urchin have indicated that urochordates might be the closest invertebrate sister group of vertebrates, rather than

Sarah J. Bourlat; Thorhildur Juliusdottir; Christopher J. Lowe; Robert Freeman; Jochanan Aronowicz; Mark Kirschner; Eric S. Lander; Michael Thorndyke; Hiroaki Nakano; Andrea B. Kohn; Andreas Heyland; Leonid L. Moroz; Richard R. Copley; Maximilian J. Telford

2006-01-01

363

A novel multi-domain mucin-like glycoprotein of Cryptosporidium parvum mediates invasion 1 Note: Nucleotide sequence data reported in this paper are available in the EMBL, GenBank™ and DDJB databases under the accession number AF068065. 1 , 2 A portion of the amino acid sequence of GP900 was presented at the 47th annual meeting of the Society of Protozoologists and 3rd Workshop on opportunistic Protozoan Pathogens in Cleveland, Ohio, June 1994. 2  

Microsoft Academic Search

Cryptosporidium parvum is a protozoan parasite which produces self-limited disease in immunocompetent hosts and devastating, persistent diarrhea in immunocompromised individuals. There is no effective treatment for cryptosporidiosis and little is known about the basic biology of the organism. Cloning and sequence analysis of the gene encoding GP900, a previously identified >900 kDa glycoprotein, predicts a mucin-like glycoprotein composed of distal

Debra A Barnes; Alain Bonnin; Jin-Xing Huang; Laurent Gousset; Jie Wu; Jiri Gut; Patricia Doyle; Jean-Francois Dubremetz; Honorine Ward; Carolyn Petersen

1998-01-01

364

Phylogeny of the Haplosporidia (Eukaryota: Alveolata) based on small subunit ribosomal RNA gene sequence.  

PubMed

The phylogenetic position of the phylum Haplosporidia was investigated with the complete small subunit rRNA gene sequences from 5 species in the phylum: Haplosporidium nelsoni and Haplosporidium costale, parasites of the eastern oyster Crassostrea virginica; Haplosporidium louisiana, a parasite of the mudcrab Panopeus herbstii; Minchinia teredinis, a parasite of shipworms (Teredo spp.) and Urosporidium crescens, a hyperparasite found in metacercariae of the trematode Megalophallus sp. in the blue crab, Callinectes sapidus. Multiple alignments of small subunit rRNA gene sequences included the 5 haplosporidian taxa and 14 taxa in the alveolate phyla Ciliophora, Dinoflagellida, and Apicomplexa. Maximum parsimony analysis placed the phylum Haplosporidia as a monophyletic group within the alveolate clade, as a taxon of equal rank with the other 3 alveolate phyla, and as a sister taxon to the clade composed of the phyla Dinoflagellida and Apicomplexa. Transversionally weighted parsimony placed the haplosporidians as a sister taxon to the ciliates. A separate analysis focused on the relationships of species in the genus Haplosporidium. Analyses were conducted with the haplosporidians as a functional ingroup, using each of the alveolate phyla individually as functional outgroups. The results indicated that species in the genus Haplosporidium do not form a monophyletic assemblage. As such, the present morphological criteria for distinguishing the genera Haplosporidium and Minchinia are insufficient. PMID:8691370

Flores, B S; Siddall, M E; Burreson, E M

1996-08-01

365

Lysine acetyltransferase GCN5b interacts with AP2 factors and is required for Toxoplasma gondii proliferation.  

PubMed

Histone acetylation has been linked to developmental changes in gene expression and is a validated drug target of apicomplexan parasites, but little is known about the roles of individual histone modifying enzymes and how they are recruited to target genes. The protozoan parasite Toxoplasma gondii (phylum Apicomplexa) is unusual among invertebrates in possessing two GCN5-family lysine acetyltransferases (KATs). While GCN5a is required for gene expression in response to alkaline stress, this KAT is dispensable for parasite proliferation in normal culture conditions. In contrast, GCN5b cannot be disrupted, suggesting it is essential for Toxoplasma viability. To further explore the function of GCN5b, we generated clonal parasites expressing an inducible HA-tagged dominant-negative form of GCN5b containing a point mutation that ablates enzymatic activity (E703G). Stabilization of this dominant-negative GCN5b was mediated through ligand-binding to a destabilization domain (dd) fused to the protein. Induced accumulation of the ddHAGCN5b(E703G) protein led to a rapid arrest in parasite replication. Growth arrest was accompanied by a decrease in histone H3 acetylation at specific lysine residues as well as reduced expression of GCN5b target genes in GCN5b(E703G) parasites, which were identified using chromatin immunoprecipitation coupled with microarray hybridization (ChIP-chip). Proteomics studies revealed that GCN5b interacts with AP2-domain proteins, apicomplexan plant-like transcription factors, as well as a "core complex" that includes the co-activator ADA2-A, TFIID subunits, LEO1 polymerase-associated factor (Paf1) subunit, and RRM proteins. The dominant-negative phenotype of ddHAGCN5b(E703G) parasites, considered with the proteomics and ChIP-chip data, indicate that GCN5b plays a central role in transcriptional and chromatin remodeling complexes. We conclude that GCN5b has a non-redundant and indispensable role in regulating gene expression required during the Toxoplasma lytic cycle. PMID:24391497

Wang, Jiachen; Dixon, Stacy E; Ting, Li-Min; Liu, Ting-Kai; Jeffers, Victoria; Croken, Matthew M; Calloway, Myrasol; Cannella, Dominique; Hakimi, Mohamed Ali; Kim, Kami; Sullivan, William J

2014-01-01

366

Identification of T. gondii Myosin Light Chain-1 as a Direct Target of TachypleginA-2, a Small-Molecule Inhibitor of Parasite Motility and Invasion  

PubMed Central

Motility of the protozoan parasite Toxoplasma gondii plays an important role in the parasite’s life cycle and virulence within animal and human hosts. Motility is driven by a myosin motor complex that is highly conserved across the Phylum Apicomplexa. Two key components of this complex are the class XIV unconventional myosin, TgMyoA, and its associated light chain, TgMLC1. We previously showed that treatment of parasites with a small-molecule inhibitor of T. gondii invasion and motility, tachypleginA, induces an electrophoretic mobility shift of TgMLC1 that is associated with decreased myosin motor activity. However, the direct target(s) of tachypleginA and the molecular basis of the compound-induced TgMLC1 modification were unknown. We show here by “click” chemistry labelling that TgMLC1 is a direct and covalent target of an alkyne-derivatized analogue of tachypleginA. We also show that this analogue can covalently bind to model thiol substrates. The electrophoretic mobility shift induced by another structural analogue, tachypleginA-2, was associated with the formation of a 225.118 Da adduct on S57 and/or C58, and treatment with deuterated tachypleginA-2 confirmed that the adduct was derived from the compound itself. Recombinant TgMLC1 containing a C58S mutation (but not S57A) was refractory to click labelling and no longer exhibited a mobility shift in response to compound treatment, identifying C58 as the site of compound binding on TgMLC1. Finally, a knock-in parasite line expressing the C58S mutation showed decreased sensitivity to compound treatment in a quantitative 3D motility assay. These data strongly support a model in which tachypleginA and its analogues inhibit the motility of T. gondii by binding directly and covalently to C58 of TgMLC1, thereby causing a decrease in the activity of the parasite’s myosin motor.

Leung, Jacqueline M.; Tran, Fanny; Pathak, Ravindra B.; Poupart, Severine; Heaslip, Aoife T.; Ballif, Bryan A.; Westwood, Nicholas J.; Ward, Gary E.

2014-01-01

367

Cryptosporidium parvum appears to lack a plastid genome.  

PubMed

Surprisingly, unlike most Apicomplexa, Cryptosporidium parvum appears to lack a plastid genome. Primers based upon the highly conserved plastid small- or large-subunit rRNA (SSU/LSU rRNA) and the tufA-tRNAPhe genes of other members of the phylum Apicomplexa failed to amplify products from intracellular stages of C. parvum, whereas products were obtained from the plastid-containing apicomplexans Eimeria bovis and Toxoplasma gondii, as well as the plants Allium stellatum and Spinacia oleracea. Dot-blot hybridization of sporozoite genomic DNA (gDNA) supported these PCR results. A T. gondii plastid-specific set of probes containing SSU/LSU rRNA and tufA-tRNA(Phe) genes strongly hybridized to gDNA from a diverse group of plastid-containing organisms including three Apicomplexa, two plants, and Euglena gracilis, but not to those without this organelle including C. parvum, three kinetoplastids, the yeast Saccharomyces cerevisiae, mammals and the eubacterium Escherichia coli. Since the origin of the plastid in other apicomplexans is postulated to be the result of a secondary symbiogenesis of either a red or a green alga, the most parsimonious explanation for its absence in C. parvum is that it has been secondarily lost. If confirmed, this would indicate an alternative evolutionary fate for this organelle in one member of the Apicomplexa. It also suggests that unlike the situation with other diseases caused by members of the Apicomplexa, drug development against cryptosporidiosis targeting a plastid genome or metabolic pathways associated with it may not be useful. PMID:10708370

Zhu, G; Marchewka, M J; Keithly, J S

2000-02-01

368

[The taxonomic rank and place of Colpodellida in the system of the Protista].  

PubMed

The analysis of ultrastructure organisation and divergent processes in Colpodellida, Perkinsida, Gregarinea and Coccidea has confirmed the presence of unique basic structures in all of these organisms and the necessity to combine them into the single phylum Sporozoa. A taxonomic rank and place of Colpodellida in the system of living organisms is represented as follows: phylum Sporozoa Leuckart, 1879; em. Krylov, Mylnikov, 1986. (Syn.: Apicomplexa Levine, 1970). Predators or parasites. Common basic structure: pellicular membranes, subpellicular microtubules, micropores, conoid, rhoptries and micronemes, tubular mitochondrial cristae. Class Perkinsea Levine, 1978. Predators or parasites, vegetative stages with two heterodynamic flagella. Subclass 1. Colpodellia nom. nov. (Syn.: Spiromonadia Krylov, Mylnikov, 1986). Predators, two heterodynamic flagella with string-like mastigonemes (if present), division is exclusively within a cyst, with 2-4 daughter cells being produced, extrusomes are trichocyst-like. Subclass 2. Perkinsia Levine, 1978. Parasites, zoospores with two heterodynamic flagella, mastigonemes (if present) bristle-like or string-like. PMID:10750150

Myl'nikov, A P; Krylov, M V; Frolov, A O

2000-01-01

369

Characterization of a conserved extrachromosomal element isolated from the avian malarial parasite Plasmodium gallinaceum.  

PubMed Central

We have identified a conserved, repeated, and highly transcribed DNA element from the avian malarial parasite Plasmodium gallinaceum. The element produced multiple transcripts in both zygotes and asexual blood stages of this parasite. It was found to be highly conserved in all of five malarial species tested and hybridized at reduced stringency to other members of the phylum Apicomplexa, including the genera Babesia, Eimeria, Toxoplasma, and Theileria. The copy number of the element was about 15, and it had a circularly permuted restriction map with a repeat unit length of about 6.2 kilobases. It could be separated from the main genomic DNA by using sucrose gradients and agarose gels, and it migrated separately from the recognized Plasmodium chromosomes on pulse-field gels. In the accompanying paper (S. M. Aldritt, J. T. Joseph, and D. F. Wirth, Mol. Cell. Biol. 9:3614-3620, 1989), evidence is presented that element contains the mitochondrial genes for the protein cytochrome b and a fragment of the large rRNA. We postulate that this element is an episome in the mitochondria of the obligate parasites belonging to the phylum Apicomplexa. Images

Joseph, J T; Aldritt, S M; Unnasch, T; Puijalon, O; Wirth, D F

1989-01-01

370

Jumbled genomes: missing Apicomplexan synteny.  

PubMed

Whole-genome comparisons provide insight into genome evolution by informing on gene repertoires, gene gains/losses, and genome organization. Most of our knowledge about eukaryotic genome evolution is derived from studies of multicellular model organisms. The eukaryotic phylum Apicomplexa contains obligate intracellular protist parasites responsible for a wide range of human and veterinary diseases (e.g., malaria, toxoplasmosis, and theileriosis). We have developed an in silico protein-encoding gene based pipeline to investigate synteny across 12 apicomplexan species from six genera. Genome rearrangement between lineages is extensive. Syntenic regions (conserved gene content and order) are rare between lineages and appear to be totally absent across the phylum, with no group of three genes found on the same chromosome and in the same order within 25 kb up- and downstream of any orthologous genes. Conserved synteny between major lineages is limited to small regions in Plasmodium and Theileria/Babesia species, and within these conserved regions, there are a number of proteins putatively targeted to organelles. The observed overall lack of synteny is surprising considering the divergence times and the apparent absence of transposable elements (TEs) within any of the species examined. TEs are ubiquitous in all other groups of eukaryotes studied to date and have been shown to be involved in genomic rearrangements. It appears that there are different criteria governing genome evolution within the Apicomplexa relative to other well-studied unicellular and multicellular eukaryotes. PMID:21504890

DeBarry, Jeremy D; Kissinger, Jessica C

2011-10-01

371

Library of Apicomplexan Metabolic Pathways: a manually curated database for metabolic pathways of apicomplexan parasites  

PubMed Central

The Library of Apicomplexan Metabolic Pathways (LAMP, http://www.llamp.net) is a web database that provides near complete mapping from genes to the central metabolic functions for some of the prominent intracellular parasites of the phylum Apicomplexa. This phylum includes the causative agents of malaria, toxoplasmosis and theileriosis—diseases with a huge economic and social impact. A number of apicomplexan genomes have been sequenced, but the accurate annotation of gene function remains challenging. We have adopted an approach called metabolic reconstruction, in which genes are systematically assigned to functions within pathways/networks for Toxoplasma gondii, Neospora caninum, Cryptosporidium and Theileria species, and Babesia bovis. Several functions missing from pathways have been identified, where the corresponding gene for an essential process appears to be absent from the current genome annotation. For each species, LAMP contains interactive diagrams of each pathway, hyperlinked to external resources and annotated with detailed information, including the sources of evidence used. We have also developed a section to highlight the overall metabolic capabilities of each species, such as the ability to synthesize or the dependence on the host for a particular metabolite. We expect this new database will become a valuable resource for fundamental and applied research on the Apicomplexa.

Shanmugasundram, Achchuthan; Gonzalez-Galarza, Faviel F.; Wastling, Jonathan M.; Vasieva, Olga; Jones, Andrew R.

2013-01-01

372

Sirtuins of parasitic protozoa: In search of function(s)  

PubMed Central

The SIR2 family of NAD+-dependent protein deacetylases, collectively called sirtuins, has been of central interest due to their proposed roles in life-span regulation and ageing. Sirtuins are one group of environment sensors of a cell interpreting external information and orchestrating internal responses at the sub-cellular level, through participation in gene regulation mechanisms. Remarkably conserved across all kingdoms of life SIR2 proteins in several protozoan parasites appear to have both conserved and intriguing unique functions. This review summarises our current knowledge of the members of the sirtuin families in Apicomplexa, including Plasmodium, and other protozoan parasites such as Trypanosoma and Leishmania. The wide diversity of processes regulated by SIR2 proteins makes them targets worthy of exploitation in anti-parasitic therapies.

Religa, Agnieszka A.; Waters, Andrew P.

2012-01-01

373

Optimizing bioluminescence imaging to study protozoan parasite infections.  

PubMed

Bioluminescence imaging is a non-invasive technique which can be used to monitor infections in real-time. However, its utility is restricted by difficulties in detecting pathogens in deep tissue. 'Red-shifted' luciferases, which emit light of longer wavelength than standard bioluminescence-generating proteins, greatly enhance sensitivity, and have wide applicability for studying parasite infections. PMID:24485045

Taylor, Martin C; Kelly, John M

2014-04-01

374

Colonization of the uterus by the oral protozoan Entamoeba gingivalis.  

PubMed

Pap smears occasionally reveal protozoa of the genus Entamoeba in the uterus of intrauterine device (IUD) users, but definitive identification of the species involved has not been possible. Using riboprinting, a technique that compares ribosomal RNA gene sequences, we present evidence that the organism is Entamoeba gingivalis, an inhabitant of the mouth. Colonization most likely occurs via orogenital contact and requires the presence of an IUD and a concomitant bacterial infection. PMID:1539749

Clark, C G; Diamond, L S

1992-02-01

375

[Oral protozoans and diabetes: study in 117 patients].  

PubMed

A study on the presence of oral Entamoeba gingivalis and Trichomonas tenax has been carried out on calculus or dental plaque from 117 diabetic subjects. Statistical analysis of results shows no correlation between diabetes and protozoa. The same frequency was found between diabetic and normal subjects. Nevertheless, a significant relation has been found between the diabetes and the yeasts. PMID:372177

Cambon, M; Petavy, A F; Guillot, J; Glanddier, Y; Deguillaume, J; Coulet, M

1979-03-01

376

Early detection of protozoan grazers in algal biofuel cultures.  

PubMed

Future micro-algal biofuels will most likely be derived from open-pond production systems. These are by definition open to "invasion" by grazers, which could devastate micro-algal mass-cultures. There is an urgent requirement for methodologies capable of early detection and control of grazers in dense algal cultures. In this study a model system employing the marine alga Nannochloropsis oculata was challenged by grazers including ciliates, amoebae and a heterotrophic dinoflagellate. A FlowCAM flow-cytometer was used to detect all grazers investigated (size range <20->80 ?m in length) in the presence of algae. Detection limits were <10 cells ml(-1) for both "large" and "small" model grazers, Euplotes vannus (80 × 45 ?m) and an unidentified holotrichous ciliate (~18 × 8 ?m) respectively. Furthermore, the system can distinguish the presence of ciliates in N. oculata cultures with biotechnologically relevant cell densities; i.e. >1.4 × 10(8) cells ml(-1) (>0.5 g l(-1) dry wt.). PMID:22464416

Day, John G; Thomas, Naomi J; Achilles-Day, Undine E M; Leakey, Raymond J G

2012-06-01

377

Experimental infections with the protozoan parasite Histomonas meleagridis: a review.  

PubMed

In recent years, a number of studies about Histomonas meleagridis, and more specifically about experiments in vivo involving H. meleagridis to investigate the pathogenicity and efficacy of drugs or vaccines, have been published. Together with older publications, a considerable amount of information about experimental infections with H. meleagridis exist, which is helpful for planning future animal studies and can reduce the number of birds used in such studies toward better animal welfare. One hundred sixty-seven publications describing experimental infections with H. meleagridis were published in scientific journals between 1920 and 2012. One hundred forty-two of these publications describe infections of turkeys (Meleagris gallopavo) and 52 infections of chickens (Gallus gallus). In 18 studies, experiments involving other species were done. The most popular routes of infection were the intracloacal application of histomonal trophozoites from culture material, from lesions or from feces of infected birds, or using larvae of the cecal worm Heterakis gallinarum (83 studies) and the oral application of eggs or other stages of the cecal worm containing histomonal stages (83 studies). During the last 10 years, intracloacal application of trophozoites has become the most popular way to experimentally infect birds with H. meleagridis due to its high reproducibility and reliability. In most studies, infection doses of several 10,000 or 100,000 histomonal trophozoites were used for infection, and the resulting mortality in turkeys was more than 70 %. First mortality can occur as early as 6 days p.i.; peak mortality usually is 13-15 days p.i. Lower infection doses may delay mortality about 2 days. In chickens infected by the intracloacal route, mortality and clinical signs are rare, but infection rates are similar. Cecal lesions can be observed from 3 to 4 days p.i., lesions up to 3 weeks p.i.; liver lesions may be lacking completely or be present only in a small number of birds. In most studies infecting birds with Heterakis eggs containing histomonal stages, several 100 to 1,000 Heterakis eggs were used. However, lower doses might be sufficient, as infection with as few as 58 eggs per bird caused a mortality up to 90 % in turkeys. Clinical symptoms start 9 days p.i., and first mortality occurs after 12 days, while most of the infected birds die between 19 and 21 days p.i. The infectivity of Heterakis eggs containing histomonal stages for chickens is similar as for turkeys, but mortality and clinical signs are rare. Further infection was done by oral application of histomonal trophozoites either grown in culture or using lesions or feces of infected birds (26 studies). These yielded very mixed results, with infection rates between 0 and more than 80 % in turkeys and chickens. After successful oral infection of turkeys, mortality occurs at roughly the same time as after intracloacal infection. Further 18 studies employed seeder birds to infect in-contact birds. Other means of infection were exposure to contaminated soil or litter (22 studies), feeding contaminated earthworms (7 studies), intracecal inoculation (4 studies), or parenteral injection (4 studies). Main methods to assess the course of the infection were mortality, observation of clinical signs and pathological lesions, monitoring of the weight of the infected birds, and detection of the parasite by various methods. PMID:23160894

Hauck, Rüdiger; Hafez, Hafez M

2013-01-01

378

The Integration of Cellular and Humoral Responses to Protozoan Parasites.  

National Technical Information Service (NTIS)

Surviving splenocytes form cyclophosphamide-treated immune donors can confer immunity to challenge with virulent P. berghei. During progress of infection of young rats with P. berghei, splenic erythropoiesis predominates over formation of immune oriented ...

A. Zuckerman C. L. Greenblatt D. T. Spira

1974-01-01

379

The Integration of Cellular and Humoral Responses to Protozoan Parasites.  

National Technical Information Service (NTIS)

The immunological mechanisms acting against the infection of rats with Plasmodium berghei and of mice infected with Leishmania tropica have been studied. In addition a system of serotyping of leishmania strains, using their excreted factor (EF) and of gro...

A. Zuckerman C. L. Greenblatt D. T. Spira

1975-01-01

380

Integration of Cellular and Humoral Responses to Protozoan Parasites.  

National Technical Information Service (NTIS)

The immunological mechanisms against Plasmodium berghei and Leishmania tropica have been studied. The humoral component of anti-malarial immunity was investigated by neutralization of small infective inocula. The neutralizing antibody in hyperimmune rat s...

A. Zuckerman C. L. Greenblatt D. T. Spira

1973-01-01

381

Mineralization of nitrogen by protozoan activity in soil  

Microsoft Academic Search

In general, more than 95% of the nitrogen in soils is present in organic forms. This nitrogen is not directly available to plants unless microbial decomposition takes place with the release of mineral nitrogen. In modern agriculture, nitrogen is often applied to arable soils as a fertilizer to support high levels of crop production. Nitrogen is one of the essential

P. J. Kuikman

1990-01-01

382

Chemosensory responses of a protozoan are modified by antitubulins.  

PubMed Central

Modification of a behavioral response of a marine dinoflagellate to chemical cues is described. Negative response to choline was modified by the antitubulins vincristine, vinblastine, griseofulvin, and trifluralin, but not by colchicine. Positive responses to 3,4-dihydroxyphenylalanine were unaffected by these drugs.

Levandowsky, M; Hauser, D C; Glassgold, J M

1975-01-01

383

Importance of Nonenteric Protozoan Infections in Immunocompromised People  

PubMed Central

Summary: There are many neglected nonenteric protozoa able to cause serious morbidity and mortality in humans, particularly in the developing world. Diseases caused by certain protozoa are often more severe in the presence of HIV. While information regarding neglected tropical diseases caused by trypanosomatids and Plasmodium is abundant, these protozoa are often not a first consideration in Western countries where they are not endemic. As such, diagnostics may not be available in these regions. Due to global travel and immigration, this has become an increasing problem. Inversely, in certain parts of the world (particularly sub-Saharan Africa), the HIV problem is so severe that diseases like microsporidiosis and toxoplasmosis are common. In Western countries, due to the availability of highly active antiretroviral therapy (HAART), these diseases are infrequently encountered. While free-living amoebae are rarely encountered in a clinical setting, when infections do occur, they are often fatal. Rapid diagnosis and treatment are essential to the survival of patients infected with these organisms. This paper reviews information on the diagnosis and treatment of nonenteric protozoal diseases in immunocompromised people, with a focus on patients infected with HIV. The nonenteric microsporidia, some trypanosomatids, Toxoplasma spp., Neospora spp., some free-living amoebae, Plasmodium spp., and Babesia spp. are discussed.

Barratt, J. L. N.; Harkness, J.; Marriott, D.; Ellis, J. T.; Stark, D.

2010-01-01

384

MYST Family Histone Acetyltransferases in the Protozoan Parasite Toxoplasma gondii  

Microsoft Academic Search

Received 14 July 2005\\/Accepted 26 September 2005 The restructuring of chromatin precedes tightly regulated events such as DNA transcription, replication, and repair. One type of chromatin remodeling involves the covalent modification of nucleosomes by histone acetyltrans- ferase (HAT) complexes. The observation that apicidin exerts antiprotozoal activity by targeting a histone deacetyl- transferase has prompted our search for more components of

Aaron T. Smith; Samantha D. Tucker-Samaras; Alan H. Fairlamb

2005-01-01

385

Gene Survey of the Pathogenic Protozoan Trypanosoma cruzi  

Microsoft Academic Search

We have performed a survey of the active genes in the important human pathogen Trypanosoma cruzi by analyzing 5013 expressed sequence tags (ESTs) generated from a normalized epimastigote cDNA library. Clustering of all sequences resulted in 771 clusters, comprising 54% of the ESTs. In total, the ESTs corresponded to 3054 transcripts that might represent one-fourth of the total gene repertoire

Betina M. Porcel; Anh-Nhi Tran; Martti Tammi; Zoltan Nyarady; Maria Rydåker; Turan P. Urmenyi; Edson Rondinelli; Ulf Pettersson; Bjorn Andersson; Lena Åslund

2000-01-01

386

Cyclospora cayetanensis: this emerging protozoan pathogen in Mexico.  

PubMed

A Mexican airline pilot had clinical manifestations of illness after a five-day stay in Lima, Peru. Six months later in Mexico, he was given a diagnosis of infection with Cyclospora cayetanensis by using coproparasitoscopic serial tests. He was treated twice with nitazoxadine successfully. PMID:24379243

Sánchez-Vega, José T; Cabrera-Fuentes, Héctor A; Romero-Olmedo, Addi J; Ortiz-Frías, José L; Sokolina, Flura; Barreto, Guillermo

2014-02-01

387

Heat Shock Proteins in Protozoan Parasites – Leishmania spp  

Microsoft Academic Search

\\u000a In this review, we shall look into the heat shock proteins of kinetoplastid protozoa of the genus Leishmania. The leishmaniae possess a full complement of molecular chaperones, with peculiar additions. Heat shock proteins play crucial\\u000a roles in both parts of the biphasic life cycle, having an impact, both on the temperature-induced differentiation from the\\u000a insect stage to the mammalian stage,

Gabi Ommen; Joachim Clos

388

Has Sarcocystis neurona Dubey et al., 1991 (Sporozoa: Apicomplexa: Sarcocystidae) cospeciated with its intermediate hosts?  

PubMed

The question of how Sarcocystis neurona is able to overcome species barrier and adapt to new hosts is central to the understanding of both the evolutionary origin of S. neurona and the prediction of its field host range. Therefore, it is worth reviewing current knowledge on S. neurona host specificity. The available host range data for S. neurona are discussed in relation to a subject of evolutionary importance-specialist or generalist and its implications to understand the strategies of host adaptation. Current evidences demonstrate that a wide range of hosts exists for S. neurona. This parasite tends to be highly specific for its definitive host but much less so for its intermediate host (I.H.). The unique specificity of S. neurona for its definitive host may be mediated by a probable long coevolutionary relationship of the parasite and carnivores in a restricted ecological niche 'New World'. This might be taken as evidence that carnivores are the 'original' host group for S. neurona. Rather, the capacity of S. neurona to exploit an unusually large number of I.H. species probably indicates that S. neurona maintains non-specificity to its I.H. as an adaptive response to insure the survival of the parasite in areas in which the 'preferred' host is not available. This review concludes with the view that adaptation of S. neurona to a new host is a complex interplay that involves a large number of determinants. PMID:19375231

Elsheikha, Hany M

2009-08-26

389

Eimeria auratae n. sp. ( Apicomplexa: Eimeriidae) infecting the lizard Mabuya aurata in Saudi Arabia  

Microsoft Academic Search

Eimeria auratae n. sp. was described from the gall bladder of the lizard Mabuya aurata collected at Al-Hofuf village, eastern region, Saudi Arabia. Morphology of sporulated as well as non-sporulated oocysts were studied. Sporulated oocysts were ellipsoidal 22–31.5×13.5–21.8 (27.7×18.5) ?m with smooth brownish-yellow bilayered wall, 1.1 (0.9–1.3) ?m. Micropyle, polar granule and oocyst residuum were absent. Sporocysts were ellipsoidal 10.5–12.8×7.5–9

Mohamed S. Alyousif; Khaled A. S. AL-Rasheid

2001-01-01

390

Eimeria auratae n. sp. (Apicomplexa: Eimeriidae) infecting the lizard Mabuya aurata in Saudi Arabia.  

PubMed

Eimeria auratae n. sp. was described from the gall bladder of the lizard Mabuya aurata collected at Al-Hofuf village, eastern region, Saudi Arabia. Morphology of sporulated as well as non-sporulated oocysts were studied. Sporulated oocysts were ellipsoidal 22-31.5x13.5-21.8 (27.7x18.5) microm with smooth brownish-yellow bilayered wall, 1.1 (0.9-1.3) microm. Micropyle, polar granule and oocyst residuum were absent. Sporocysts were ellipsoidal 10.5-12.8x7.5-9 (11.8x8.5) microm. Sporocyst residuum was present but Stieda body was absent. Sporozoites were crescent-shaped, blunt at one end and slightly tapered at the other. Eimeria species from Scincidae were compared. PMID:11267929

Alyousif, M S; AL-Rasheid, K A

2001-03-01

391

Description of the oöcysts of theree new species of Eimeria (Apicomplexa: Eimeriidae) from geckoes (Auria: Gekkonidae)  

Microsoft Academic Search

Three new species ofEimeria are described from the faeces of geckoes. Oöcysts ofEimeria vittati n. sp. fromGekko vittatus are elongate-ellipsoid 34.3 × 16.9 (32.5–36.5 × 16.5–17.5) m; shape index (mean length\\/mean width) 2.03. Its sporocysts are ovoid 11.0 × 6.5 (10–12.5 × 5–7.5) ; shape index 1.7. Oöcysts ofE. simonkingi n. sp. were found inG. vitttus and two subspecies ofPhelsuma

S. J. Ball; P. Daszak

1995-01-01

392

Isospora troglodytes n. sp. (Apicomplexa: Eimeriidae), a new coccidian species from wrens of Costa Rica.  

PubMed

Nineteen (91%) of 21 rufous-and-white wrens (Thryothorus rufalbus) and five (71%) of seven plain wrens (Cantorchilus modestus) sampled from Costa Rica were positive for a new species of Isospora. Oocysts have a thin, smooth, double, colorless wall and measure 20.1 ± 1.4 × 23.4 ± 1.5 ?m (18-24 × 20-26 ?m) with an average length-width ratio of 1.2 ?m. Sporocysts are ovoid, measure 9.5 ± 0.9 × 15.5 ± 1.1 ?m (7-12 × 12-18 ?m) with an average length-width ratio of 1.6 ?m. A nipple-like steida body continuous with the sporocyst wall and a prominent oval-shaped substeida body are present. In addition to the four sporozoites, a single compact sporocyst residuum was present in each sporocyst. This is the first description of an Isospora species from the family Troglodytidae and the first report of Isospora from the rufous-and-white wren and plain wren. PMID:22006192

Keeler, Shamus P; Yabsley, Michael J; Fox, Julie M; McGraw, Sabrina N; Hernandez, Sonia M

2012-05-01

393

Effect of gregarines (Apicomplexa: Sporozoa) on survival and weight loss of Victorwithius similis (Arachnida: Pseudoscorpiones).  

PubMed

Gregarines are common intestinal parasites of numerous invertebrate groups. Their effects on host viability and development have been a matter of debate. Although they may not be lethal to the host, they can be harmless commensals, by affecting adaptive traits, or have a beneficial relationship with the host. This study focused on determining prevalence, intensity, and change in infection intensity over time by septate gregarines, and monitoring the effects on survival and weight loss in the pseudoscorpion Victorwithius similis. Individuals (n=24 females, n=55 males and n=41 tritonymphs) were captured in the field, transported to the vivarium and bred under laboratory conditions. A high prevalence of infection was found, with 77.27% of females, 62.50% of males and 73.53% of tritonymphs harboring intense infections. Of the infected pseudoscorpions, 62% of females, 58% of males and 71% of tritonymphs did not show changes in infection intensity over time. The group that maintained intense infections survived longer than those with less intense infections (?(2)=8.642; p=0.035). Most of the results obtained indicate that relationship studied between gregarines and the pseudoscorpion V. similis might be a case of commensalism. This would explain why the infection level and prevalence was very high, as well as the apparent lack of direct costs to highly infected individuals those with infections. PMID:24480672

Bollatti, Fedra; Ceballos, Alejandra

2014-03-01

394

New species of the genus Eimeria (Apicomplexa: Coccidia) from marine fish  

Microsoft Academic Search

Six new coccidian species are described from marine fish collected on the French Mediterranean coast near Banyuls-sur-Mer and on the coast of Newfoundland. All have sporocysts with well-developed Stieda bodies and are placed into the genusEimeria: E. catalana sp. nova from the intestine ofCrenilabrus mediterraneus, E. hexagona sp. nova from the digestive tract ofOnos tricirratus, E. ivanae sp. nova from

Ji?í Lom; Iva Dykovfi

1981-01-01

395

Three new species of coccidia (Apicomplexa: Eimeriidae) from skinks, Lipinia spp. (Sauria: Scincidae), from Oceania.  

PubMed

Between September 1991 and March 1993, 25 moth skinks (Lipinia noctua) were collected from various localities on the Cook Islands, Fiji, Papua New Guinea (PNG), and Vanuatu and examined for coccidians. In addition, a single Roux's lipinia skink (Lipinia rouxi) was collected from PNG and examined for coccidia. Sixteen (64%) L. noctua were found to harbor 2 new eimerians, and L. rouxi harbored another new Eimeria sp. Oocysts of Eimeria lipinia n. sp. from 9 (36%) L. noctua from the Cook Islands, Fiji, and PNG were subspherical with a bilayered wall and measured (L × W) 18.6 × 16.9 ?m, with a L/W ratio of 1.1. Both micropyle and oocyst residuum were absent, but a polar granule was present. Oocysts of Eimeria melanesia n. sp. from 6 (24%) L. noctua from Fiji and Vanuatu and a single L. rouxi from PNG were subspherical to ellipsoidal with a bilayered wall and measured 19.8 × 17.5 ?m, and L/W was 1.1. Both micropyle and oocyst residuum were absent, but a single or fragmented polar granule was present. Oocysts of Eimeria lessoni n. sp. from 1 (4%) L. noctua from PNG were cylindroidal with a bilayered wall and measured 28.1 × 15.7 ?m, and L/W was 1.8. Both micropyle and oocyst residuum were absent, but a single polar granule was present. These represent the third report of Eimeria spp. reported from any host on PNG and the only coccidians, to our knowledge, ever described from L. noctua and L. rouxi and from the Cook Islands and Vanuatu. PMID:23984908

McAllister, Chris T; Duszynski, Donald W; Austin, Christopher C; Fisher, Robert N

2013-12-01

396

Redescription of Eimeria zarudnyi Alyousif & Al-Shawa, 2003 as Choleoeimeria zarudnyi n. comb. (Apicomplexa: Eimeriidae).  

PubMed

Coprological examination of the worm lizard Diplometopon zarudnyi Nikolskii revealed the presence of oöcysts of Choleoeimeria zarudnyi (Alyousif & Al-Shawa, 2003) n. comb. in five (17%) of the 30 lizards examined. Sporulated oöcysts were found in the faeces and the gallbladder contents. These are tetrasporocystic, ellipsoidal, 25-32 × 18-25 (mean 27 × 22) ?m, with a smooth bi-layered wall. The dizoic sporocysts are ovoidal, 10-13 × 6-9 (mean 11 × 7) ?m, with a granulated sporocyst residuum. Sporozoites are banana-shaped with an average size of 13 × 3 ?m. Endogenous stages (meronts, gamonts and gametes) are confined to the gallbladder epithelium and the infected cells were hypertrophied. Based on the morphological features of the exogenous stages and the endogenous development of the present parasite, its generic affiliation is revised and Eimeria zarudnyi Alyousif & Al-Shawa, 2003 is transferred to the genus Choleoeimeria. PMID:23673696

Abdel-Baki, Abdel-Azeem S; Abdel-Haleem, Heba M; Al-Quraishy, Saleh

2013-06-01

397

CRYPTOSPORIDIUM HOMINIS N. SP (APICOMPLEXA : CRYPTOSPORIDIIDAE) FROM HOMO SAPIENS. (R826138)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

398

A novel isospora species (apicomplexa: eimeriidae) from warblers (passeriformes: parulidae) of costa rica.  

PubMed

Abstract :? Five of 16 (31%) rufous-capped warblers (Basileuterus rufifrons) and 2 of 5 (40%) ovenbirds ( Seiurus aurocapilla ) sampled from Costa Rica were positive for a novel species of Isospora. Oocysts have a thin, smooth, double-layered, colorless wall and measure 22.3 ?m ± 1.6 ?m × 24.3 ?m ± 1.5 ?m (19-25 ?m × 21-28 ?m) with an average length-width (L/W) ratio of 1.0 (1-1.3). Oocyst residuum and micropyle are absent, but 0-4 spherical to cigar-shaped polar granules (1-2.5 ?m) are present. Sporocysts are ovoid and measure 11.8 ?m ± 0.9 ?m × 16 ?m ± 1.7 ?m (10-14 ?m × 12-19 ?m) with an average L/W ratio of 1.6 (1.0-1.9). A knob-like Stieda body continuous with the sporocyst wall and a trapezoidal compartmentalized substieda body are present. Each sporocyst contained 4 sporozoites and a diffuse sporocyst residuum consisting of many variable-sized granules, some as large as 2 ?m. This is the second description of an Isospora species in New World warblers (Passeriformes: Parulidae) and the first report of Isospora from both the rufous-capped warbler and ovenbird. PMID:24456073

Keeler, Shamus P; Yabsley, Michael J; Adams, Henry C; Hernandez, Sonia M

2014-06-01

399

Reporter gene expression in cell culture stages and oocysts of Eimeria nieschulzi (Coccidia, Apicomplexa)  

Microsoft Academic Search

The rat parasite Eimeria nieschulzi is a suitable model for transfection studies and was used as an additional model organism for the genus Eimeria. We describe the transfection of this apicomplexan parasites and the cultivation of transformed stages in cell culture and\\u000a in vivo. The ?-galactosidase or yellow fluorescent protein was expressed in all parasitic stages up to the second

Michael Kurth; Rolf Entzeroth

2009-01-01

400

Coccidia (Apicomplexa: Eimeriidae) of the lowland European bison Bison bonasus bonasus (L.).  

PubMed

Coprological studies conducted between 2007 and 2011 in free-roaming and captive European bison Bison bonasus (Linnaeus, 1758) from Poland revealed 11 species of Eimeria infecting the host, i.e., Eimeria alabamensis, Eimeria auburnensis, Eimeria bovis, Eimeria brasiliensis, Eimeria bukidnonensis, Eimeria canadensis, Eimeria cylindrica, Eimeria ellipsoidalis, Eimeria pellita, Eimeria subspherica, and Eimeria zuernii. The typical host for all isolated species is cattle. The most prevalent species was E. bovis (29.7%), while E. brasiliensis was the rarest (0.5%). Five of the species (E. bovis, E. bukidnonensis, E. canadensis, E. ellipsoidalis, E. zuernii) have been observed previously in bison by other authors, 3 species were noticed by us in bison previously (E. alabamensis, E. cylindrica, E. pellita), while for 3 species (E. auburnensis, E. brasiliensis, and E. subspherica) these are new host and locality records. Oocysts of two species (E. brasiliensis, E. bukidnonensis) were noted only in the feces of bison kept in captivity. Moreover, the prevalence of positive samples was higher in the group of captive animals (55.4%) in comparison with the free-roaming herds (29.5%); although, oocysts per gram (OPG), counted with the conventional McMaster technique, was comparable in both groups, reaching maximally 6550 and 6400 in free-roaming and captive individuals, respectively. Overall, 142 fecal samples from 424 samples examined were positive for Eimeria (prevalence=33.5%). Age-related analysis revealed a higher percentage of Eimeria spp. positive samples and higher OPG values in bison under 1 year old as compared to older individuals (93.3% and 50-4050; 37.3% and 50-550, respectively). Additionally, greater eimerian species diversity was present among calves in comparison with older bison. In most cases single-species infections were observed (59.8%) with a predominance of E. bovis (85.9%). Multiple-species infections consisted of 2-7 species, usually including E. bovis. The observation was made that E. bovis infection appears conducive to the host acquiring more eimerian species. No symptoms of clinical coccidiosis occurred during the study. PMID:24702772

Pyziel, Anna M; Jó?wikowski, Micha?; Demiaszkiewicz, Aleksander W

2014-05-28