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1

Structural and evolutionary divergence of eukaryotic protein kinases in Apicomplexa  

PubMed Central

Background The Apicomplexa constitute an evolutionarily divergent phylum of protozoan pathogens responsible for widespread parasitic diseases such as malaria and toxoplasmosis. Many cellular functions in these medically important organisms are controlled by protein kinases, which have emerged as promising drug targets for parasitic diseases. However, an incomplete understanding of how apicomplexan kinases structurally and mechanistically differ from their host counterparts has hindered drug development efforts to target parasite kinases. Results We used the wealth of sequence data recently made available for 15 apicomplexan species to identify the kinome of each species and quantify the evolutionary constraints imposed on each family of apicomplexan kinases. Our analysis revealed lineage-specific adaptations in selected families, namely cyclin-dependent kinase (CDK), calcium-dependent protein kinase (CDPK) and CLK/LAMMER, which have been identified as important in the pathogenesis of these organisms. Bayesian analysis of selective constraints imposed on these families identified the sequence and structural features that most distinguish apicomplexan protein kinases from their homologs in model organisms and other eukaryotes. In particular, in a subfamily of CDKs orthologous to Plasmodium falciparum crk-5, the activation loop contains a novel PTxC motif which is absent from all CDKs outside Apicomplexa. Our analysis also suggests a convergent mode of regulation in a subset of apicomplexan CDPKs and mammalian MAPKs involving a commonly conserved arginine in the ?C helix. In all recognized apicomplexan CLKs, we find a set of co-conserved residues involved in substrate recognition and docking that are distinct from metazoan CLKs. Conclusions We pinpoint key conserved residues that can be predicted to mediate functional differences from eukaryotic homologs in three identified kinase families. We discuss the structural, functional and evolutionary implications of these lineage-specific variations and propose specific hypotheses for experimental investigation. The apicomplexan-specific kinase features reported in this study can be used in the design of selective kinase inhibitors. PMID:22047078

2011-01-01

2

GCN5-B is a Novel Nuclear Histone Acetyltransferase that is Crucial for Viability in the Protozoan Parasite Toxoplasma gondii.  

E-print Network

??Indiana University-Purdue University Indianapolis (IUPUI) Infection with the single-celled parasite Toxoplasma gondii (phylum Apicomplexa) is usually benign in normal healthy individuals, but can cause congenital… (more)

Dixon, Stacey E.

2011-01-01

3

Particularities of mitochondrial structure in parasitic protists (Apicomplexa and Kinetoplastida).  

PubMed

Without mitochondria, eukaryotic cells would depend entirely on anaerobic glycolysis for ATP generation. This also holds true for protists, both free-living and parasitic. Parasitic protists include agents of human and animal diseases that have a huge impact on world populations. In the phylum Apicomplexa, several species of Plasmodium cause malaria, whereas Toxoplasma gondii is a cosmopolite parasite found on all continents. Flagellates of the order Kinetoplastida include the genera Leishmania and Trypanosoma causative agents of human leishmaniasis and (depending on the species) African trypanosomiasis and Chagas disease. Although clearly distinct in many aspects, the members of these two groups bear a single and usually well developed mitochondrion. The single mitochondrion of Apicomplexa has a dense matrix and many cristae with a circular profile. The organelle is even more peculiar in the order Kinetoplastida, exhibiting a condensed network of DNA at a specific position, always close to the flagellar basal body. This arrangement is known as Kinetoplast and the name of the order derived from it. Kinetoplastids also bear glycosomes, peroxisomes that concentrate enzymes of the glycolytic cycle. Mitochondrial volume and activity is maximum when glycosomal is low and vice versa. In both Apicomplexa and trypanosomatids, mitochondria show particularities that are absent in other eukaryotic organisms. These peculiar features make them an attractive target for therapeutic drugs for the diseases they cause. PMID:19379828

de Souza, Wanderley; Attias, Márcia; Rodrigues, Juliany C F

2009-10-01

4

Efficacy of eleven antimicrobials against a gregarine parasite (Apicomplexa: Protozoa)  

PubMed Central

Background The Apicomplexa are a diverse group of obligate protozoan parasites infesting a wide range of invertebrate and vertebrate hosts including humans. These parasites are notoriously difficult to control and many species continue to evolve resistance to commercial antibiotics. In this study, we sought to find an effective chemotherapeutic treatment against arthropod gregarines (Apicomplexa), and to identify candidate compounds for testing against other groups of protozoan parasites. Methods We tested eleven commercial antibiotics against a gregarine parasite of Romalea microptera grasshoppers. Infected insects were fed daily, lettuce containing known amounts of specific antibiotics. On Days 15 or 20, we measured the number of gregarines remaining in the digestive tract of each grasshopper. Results Treatment with metronidazole and griseofulvin in host insects significantly reduced gregarine counts, whereas, gregarine counts of insects fed, albendazole, ampicillin, chloramphenicol, fumagillin, quinine, streptomycin, sulfadimethoxine, thiabendazole or tetracycline, were not significantly different from the controls. However, albendazole produced a strong, but non-significant reduction in gregarine count, and streptomycin exhibited a non-significant antagonistic trend. Conclusion Our results confirm that gregarine infections are difficult to control and suggest the possibility that streptomycin might aggravate gregarine infection. In addition, the insect system described here, provides a simple, inexpensive, and effective method for screening antibiotics. PMID:17997852

Johny, Shajahan; Merisko, Amber; Whitman, Douglas W

2007-01-01

5

Lateral Gene Transfer of Family A DNA Polymerases between Thermophilic Viruses, Aquificae, and Apicomplexa  

PubMed Central

Bioinformatics and functional screens identified a group of Family A-type DNA Polymerase (polA) genes encoded by viruses inhabiting circumneutral and alkaline hot springs in Yellowstone National Park and the US Great Basin. The proteins encoded by these viral polA genes (PolAs) shared no significant sequence similarity with any known viral proteins but were remarkably similar to PolAs encoded by two of three families of the bacterial phylum Aquificae and by several apicoplast-targeted PolA-like proteins found in the eukaryotic phylum Apicomplexa, which includes the obligate parasites Plasmodium, Babesia, and Toxoplasma. The viral gene products share signature elements previously associated only with Aquificae and Apicomplexa PolA-like proteins and were similar to proteins encoded by prophage elements of a variety of otherwise unrelated Bacteria, each of which additionally encoded a prototypical bacterial PolA. Unique among known viral DNA polymerases, the viral PolA proteins of this study share with the Apicomplexa proteins large amino-terminal domains with putative helicase/primase elements but low primary sequence similarity. The genomic context and distribution, phylogeny, and biochemistry of these PolA proteins suggest that thermophilic viruses transferred polA genes to the Apicomplexa, likely through secondary endosymbiosis of a virus-infected proto-apicoplast, and to the common ancestor of two of three Aquificae families, where they displaced the orthologous cellular polA gene. On the basis of biochemical activity, gene structure, and sequence similarity, we speculate that the xenologous viral-type polA genes may have functions associated with diversity-generating recombination in both Bacteria and Apicomplexa. PMID:23608703

Schoenfeld, Thomas W.; Murugapiran, Senthil K.; Dodsworth, Jeremy A.; Floyd, Sally; Lodes, Michael; Mead, David A.; Hedlund, Brian P.

2013-01-01

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

Biology of the Phylum Nematomorpha  

Microsoft Academic Search

Compared with most animal phyla, the Nematomorpha, also known as hair worms, is a relatively understudied metazoan phylum. Although nematomorphs make up only 1 of 3 animal phyla specializing solely on a parasitic life style, little attention has been focused on this enigmatic group scientifically. The phylum contains two main groups. The nectonematids are parasites of marine invertebrates such as

B. Hanelt; F. Thomas; A. Schmidt-Rhaesa

2005-01-01

8

Phylum Cnidaria Origin of Diversity  

E-print Network

found on the hermit crab shell. How has so much diversity been possible in the Phylum Cnidaria 3. Coral all polyps through stolons Hydractinia #12;3 Metamorphosis is triggered by unknown cues from bacteria

Cochran-Stafira, D. Liane

9

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. PMID:8993859

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

1997-01-01

10

Effects of Artemisia annua and Foeniculum vulgare on chickens highly infected with Eimeria tenella (Phylum Apicomplexa)  

PubMed Central

Background Intensive poultry production systems depend on chemoprophylaxis with anticoccidial drugs to combat infection. A floor-pen study was conducted to evaluate the anticoccidial effect of Artemisia annua and Foeniculum vulgare on Eimeria tenella infection. Five experimental groups were established: negative control (untreated, unchallenged); positive control (untreated, challenged); a group medicated with 125 ppm lasalocid and challenged; a group medicated with A. annua leaf powder at 1.5% in feed and challenged; and a group treated with the mixed oils of A. annua and Foeniculum vulgare in equal parts, 7.5% in water and challenged. The effects of A. annua and oil extract of A. annua + F. vulgare on E. tenella infection were assessed by clinical signs, mortality, fecal oocyst output, faeces, lesion score, weight gain, and feed conversion. Results Clinical signs were noticed only in three chickens from the lasalocid group, six from the A. annua group, and nine from the A. annua?+?F. vulgare group, but were present in 19 infected chickens from the positive control group. Bloody diarrhea was registered in only two chickens from A. annua group, but in 17 chickens from the positive control group. Mortality also occurred in the positive control group (7/20). Chickens treated with A. annua had a significant reduction in faecal oocysts (95.6%; P?=?0.027) and in lesion score (56.3%; P?=?0.005) when compared to the positive control. At the end of experiment, chickens treated with A. annua leaf powder had the highest body weight gain (68.2 g/day), after the negative control group, and the best feed conversion (1.85) among all experimental groups. Conclusions Our results suggest that A. annua leaf powder (Aa-p), at 1.5% of the daily diet post-infection, can be a valuable alternative for synthetic coccidiostats, such as lasalocid. PMID:24731599

2014-01-01

11

TWO NEW EIMERIANS (APICOMPLEXA) FROM INSECTIVOROUS MAMMALS IN MADAGASCAR  

E-print Network

TWO NEW EIMERIANS (APICOMPLEXA) FROM INSECTIVOROUS MAMMALS IN MADAGASCAR Lee Couch, Juha Laakkonen The Journal of #12;#12;TWO NEW EIMERIANS (APICOMPLEXA) FROM INSECTIVOROUS MAMMALS IN MADAGASCAR Lee Couch insectivorous mammals in Madagascar were collected between spring 1999 and fall 2001. In the Afrosoricida, 21

Jernvall, Jukka

12

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

13

A phylogenetic analysis of the phylum Fibrobacteres.  

PubMed

Members of the phylum Fibrobacteres are highly efficient cellulolytic bacteria, best known for their role in rumen function and as potential sources of novel enzymes for bioenergy applications. Despite being key members of ruminants and other digestive microbial communities, our knowledge of this phylum remains incomplete, as much of our understanding is focused on two recognized species, Fibrobacter succinogenes and F. intestinalis. As a result, we lack insights regarding the environmental niche, host range, and phylogenetic organization of this phylum. Here, we analyzed over 1000 16S rRNA Fibrobacteres sequences available from public databases to establish a phylogenetic framework for this phylum. We identify both species- and genus-level clades that are suggestive of previously unknown taxonomic relationships between Fibrobacteres in addition to their putative lifestyles as host-associated or free-living. Our results shed light on this poorly understood phylum and will be useful for elucidating the function, distribution, and diversity of these bacteria in their niches. PMID:23759599

Jewell, Kelsea A; Scott, Jarrod J; Adams, Sandra M; Suen, Garret

2013-09-01

14

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

15

Photoacoustic spectroscopy of man infecting protozoans  

NASA Astrophysics Data System (ADS)

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.; Alvarado-Gil, J. J.; Vargas, H.

1998-08-01

16

Large, rapidly evolving gene families are at the forefront of host-parasite interactions in Apicomplexa.  

PubMed

SUMMARY The Apicomplexa is a phylum of parasitic protozoa, which includes the malaria parasite Plasmodium, amongst other species that can devastate human and animal health. The past decade has seen the release of genome sequences for many of the most important apicomplexan species, providing an excellent basis for improving our understanding of their biology. One of the key features of each genome is a unique set of large, variant gene families. Although closely related species share the same families, even different types of malaria parasite have distinct families. In some species they tend to be found at the ends of chromosomes, which may facilitate aspects of gene expression regulation and generation of sequence diversity. In others they are scattered apparently randomly across chromosomes. For some families there is evidence they are involved in antigenic variation, immune regulation and immune evasion. For others there are no known functions. Even where function is unknown these families are most often predicted to be exposed to the host, contain much sequence diversity and evolve rapidly. Based on these properties it is clear that they are at the forefront of host-parasite interactions. In this review I compare and contrast the genomic context, gene structure, gene expression, protein localization and function of these families across different species. PMID:25257746

Reid, Adam J

2015-02-01

17

First identification of Sarcocystis tenella (Railliet, 1886) Moulé, 1886 (Protozoa: Apicomplexa) by PCR in naturally infected sheep from Brazil.  

PubMed

Sarcocystis tenella is a dog-sheep protozoan parasite, causing a widespread enzootic muscle parasitosis and neurological disease mainly in lambs. This parasite is pathogenic to sheep and important to the economical production of sheep. The present study was initially aimed to determine Toxoplasma gondii infection and the occurrence of co-infection with other Apicomplexa parasites in 602 Brazilian sheep. Twenty of these sheep were positive with antibodies to T. gondii by MAT and IFAT-IgG tests, positive with PCR-RFLP genotyping at multiple loci, and parasites were isolated from mice infected with sheep tissue samples. Two additional sheep born in Brazil, a 2-year-old female Polwarth (Ideal) sheep, a breed originated from Australia (#1), and a 1-year-old male Corriedale sheep, a breed originated from New Zealand and Australia (#2) were positive to T. gondii antibodies by serum tests, and PCR, but negative for bioassay in mice. In genotyping at 12 loci, sheep #1 sample and #2 presented positive results only for some markers. PCR-RFLP of 18S ribosomal RNA (18S rRNA) was performed in all 22 animals to identify the possibility of co-infection of T. gondii with other Apicomplexa parasites, such as S. tenella, Neospora caninum and Hammondia hammondi, resulting in a T. gondii profile for the first 20 animals and a unique genotyping profile for sheep #1 and #2, identical to S. tenella. The 18S rRNA PCR products (approximately 310 bp) were sequenced and blasted to GenBank database at NCBI. Both samples were identical to S. tenella 18S rRNA gene (GenBank accession number L24383-1). These results suggest the existence of co-infection of S. tenella with T. gondii in ewes from Brazil. PMID:19647370

da Silva, Rodrigo Costa; Su, Chunlei; Langoni, Helio

2009-11-12

18

Effects of Artemisia annua and Foeniculum vulgare on on chickens highly infected with Eimeria tenella (Phylum Apicomplexa)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background: Intensive poultry production systems depend on chemoprophylaxis with anticoccidial drugs to combat infection. A floor-pen study was conducted to evaluate the anticoccidial effect of Artemisia annua and Foeniculum vulgare on Eimeria tenella infection. Five experimental groups were establi...

19

The Life Cycle and Fitness of Gregarine (Apicomplexa)Parasites  

E-print Network

The Life Cycle and Fitness of Gregarine (Apicomplexa)Parasites David Logan & John Janovy, Jr characteristics of gregarine parasites and how they are shaped by their own life cycle stages inside and outside an insect host. The population model is a continuous time dynamics for the parasite stages, and we examine

Logan, David

20

Resolving phylogenetic relationships within the order Enoplida (Phylum Nematoda).  

E-print Network

??The Order Enoplida (Phylum Nematoda) has been proposed as a divergent nematode lineage—Enoplid nematodes are thought to exhibit morphological and developmental characteristics present in the… (more)

Bik, Holly Marie

2010-01-01

21

Phylum Arthropoda 1. Insecta, "Palaeoptera", pp. 184-186  

E-print Network

1 INSECTA Phylum Arthropoda 1. Insecta, "Palaeoptera", pp. 184-186 Also see indicated `Boxes' on other pages 2. Evolution of wings pp. 208-211 #12;2 Phylum Arthropoda Arthropod Polyphyly? Sidnie Manton & others have argued that the Arthropoda are polyphyletic - i.e. the common ancestor was not an arthropod

Wagner, Diane

22

Structural Evidence for Actin-like Filaments in Toxoplasma gondii Using High-Resolution Low-Voltage Field Emission Scanning Electron Microscopy  

Microsoft Academic Search

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

Heide Schatten; L. David Sibley; Hans Ris

2003-01-01

23

COMPOSITE GENOME MAP AND RECOMBINATION PARAMETERS DERIVED FROM THREE ARCHETYPAL LINEAGES OF TOXOPLASMA GONDII  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 facil...

24

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

25

Phylogeny of Fish-Infecting Calyptospora species (Apicomplexa: Eimeriorina)  

EPA Science Inventory

There are numerous species of apicomplexans that infect poikilothermic vertebrates such as fishes, and possess unique morphological features that provide insight into the evolution of this important phylum of parasites. Here the relationship of the fish-infecting Calyptospora spe...

26

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

27

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. PMID:16170739

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

2009-01-01

28

A photoactivatable green-fluorescent protein from the phylum Ctenophora  

Microsoft Academic Search

Genes for the family of green-fluorescent proteins (GFPs) have been found in more than 100 species of animals, with some species containing six or more copies producing a variety of colours. Thus far, how- ever, these species have all been within three phyla: Cnidaria, Arthropoda and Chordata. We have discovered GFP-type fluorescent proteins in the phylum Ctenophora, the comb jellies.

Steven H. D. Haddock; Nadia Mastroianni; Lynne M. Christianson

2009-01-01

29

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

30

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. PMID:25057459

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

2014-01-01

31

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. PMID:21349087

Sibley, L. David

2013-01-01

32

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. PMID:22577251

Rogerio, Alexandre P.; Anibal, Fernanda F.

2012-01-01

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. PMID:23087842

Challacombe, Jean; Kuske, Cheryl

2012-01-01

34

Invasion, and short- and long-term survival of Babesia divergens (Phylum Apicomplexa) cultures in non-bovine sera and erythrocytes.  

PubMed

In order to explore the feasibility of producing a Babesia divergens live vaccine free of bovine material contaminants the parasite's ability to grow in human, sheep and horse erythrocytes and serum and serum-free medium was investigated. B. divergens was successfully maintained in bovine erythrocytes overlaid with serum-free HL-1 medium. Supplementation of the culture medium with bovine or sheep serum improved parasite growth (monitored by measuring parasitaemia and uptake of tritiated hypoxanthine) whereas horse and human sera reduced parasite growth. As assessed by Giemsa's stained and FITC-labelled blood smears, the parasite invaded all erythrocyte types. Polyparasitism was less common in sheep and horse erythrocytes than in bovine and human erythrocytes. Accole stages were observed in bovine, human and sheep but not in horse erythrocytes. Proliferation following invasion was higher in human but lower in horse and sheep erythrocytes compared with bovine erythrocytes. Long-term cultures of B. divergens reached similar peak parasitaemias in human, sheep and bovine erythrocytes. Attempts to establish long-term cultures in horse erythrocytes failed. These results suggest that B. divergens is not host specific at the level of host cell attachment and invasion. Instead, parasite survival appears to be decided once the organism has gained access into the cell. PMID:12118713

Zintl, A; Westbrook, C; Mulcahy, G; Skerrett, H E; Gray, J S

2002-06-01

35

Nubenocephalus nebraskensis n. gen., n. sp. (Apicomplexa: Actinocephalidae) from Adults of Argia bipunctulata (Odonata: Zygoptera)  

Microsoft Academic Search

Nubenocephalus nebraskensis n. gen., n. sp. (Apicomplexa: Actinocephalidae) is described from trophozoites, sporonts, gamonts, and oocysts collected from adult Argia bipunctulata (Odonata: Zygoptera). The new genus is distinguished from existing acanthosporine genera by elongate dodecahedral oocysts, without equatorial faces, that are hexagonal in equatorial cross section with equatorial and terminal spines. The epimerite is very broadly ovoid and truncated posteriorly

Richard E. Clopton; Tamara J. Percival Cook; Janovy John J. Jr

1993-01-01

36

Lateral Gene Transfer of Family A DNA Polymerases between Thermophilic Viruses, Aquificae, and Apicomplexa  

E-print Network

Article Lateral Gene Transfer of Family A DNA Polymerases between Thermophilic Viruses, Aquificae Polymerase (polA) genes encoded by viruses inhabiting circumneutral and alkaline hot springs in YellowstoneA proteins suggest that thermophilic viruses transferred polA genes to the Apicomplexa, likely through

Ahmad, Sajjad

37

Deep phylogeny and evolution of sponges (phylum Porifera).  

PubMed

Sponges (phylum Porifera) are a diverse taxon of benthic aquatic animals of great ecological, commercial, and biopharmaceutical importance. They are arguably the earliest-branching metazoan taxon, and therefore, they have great significance in the reconstruction of early metazoan evolution. Yet, the phylogeny and systematics of sponges are to some extent still unresolved, and there is an on-going debate about the exact branching pattern of their main clades and their relationships to the other non-bilaterian animals. Here, we review the current state of the deep phylogeny of sponges. Several studies have suggested that sponges are paraphyletic. However, based on recent phylogenomic analyses, we suggest that the phylum Porifera could well be monophyletic, in accordance with cladistic analyses based on morphology. This finding has many implications for the evolutionary interpretation of early animal traits and sponge development. We further review the contribution that mitochondrial genes and genomes have made to sponge phylogenetics and explore the current state of the molecular phylogenies of the four main sponge lineages (Classes), that is, Demospongiae, Hexactinellida, Calcarea, and Homoscleromorpha, in detail. While classical systematic systems are largely congruent with molecular phylogenies in the class Hexactinellida and in certain parts of Demospongiae and Homoscleromorpha, the high degree of incongruence in the class Calcarea still represents a challenge. We highlight future areas of research to fill existing gaps in our knowledge. By reviewing sponge development in an evolutionary and phylogenetic context, we support previous suggestions that sponge larvae share traits and complexity with eumetazoans and that the simple sedentary adult lifestyle of sponges probably reflects some degree of secondary simplification. In summary, while deep sponge phylogenetics has made many advances in the past years, considerable efforts are still required to achieve a comprehensive understanding of the relationships among and within the main sponge lineages to fully appreciate the evolution of this extraordinary metazoan phylum. PMID:22560777

Wörheide, G; Dohrmann, M; Erpenbeck, D; Larroux, C; Maldonado, M; Voigt, O; Borchiellini, C; Lavrov, D V

2012-01-01

38

Chordate evolution and the three-phylum system  

PubMed Central

Traditional metazoan phylogeny classifies the Vertebrata as a subphylum of the phylum Chordata, together with two other subphyla, the Urochordata (Tunicata) and the Cephalochordata. The Chordata, together with the phyla Echinodermata and Hemichordata, comprise a major group, the Deuterostomia. Chordates invariably possess a notochord and a dorsal neural tube. Although the origin and evolution of chordates has been studied for more than a century, few authors have intimately discussed taxonomic ranking of the three chordate groups themselves. Accumulating evidence shows that echinoderms and hemichordates form a clade (the Ambulacraria), and that within the Chordata, cephalochordates diverged first, with tunicates and vertebrates forming a sister group. Chordates share tadpole-type larvae containing a notochord and hollow nerve cord, whereas ambulacrarians have dipleurula-type larvae containing a hydrocoel. We propose that an evolutionary occurrence of tadpole-type larvae is fundamental to understanding mechanisms of chordate origin. Protostomes have now been reclassified into two major taxa, the Ecdysozoa and Lophotrochozoa, whose developmental pathways are characterized by ecdysis and trochophore larvae, respectively. Consistent with this classification, the profound dipleurula versus tadpole larval differences merit a category higher than the phylum. Thus, it is recommended that the Ecdysozoa, Lophotrochozoa, Ambulacraria and Chordata be classified at the superphylum level, with the Chordata further subdivided into three phyla, on the basis of their distinctive characteristics. PMID:25232138

Satoh, Noriyuki; Rokhsar, Daniel; Nishikawa, Teruaki

2014-01-01

39

Chordate evolution and the three-phylum system.  

PubMed

Traditional metazoan phylogeny classifies the Vertebrata as a subphylum of the phylum Chordata, together with two other subphyla, the Urochordata (Tunicata) and the Cephalochordata. The Chordata, together with the phyla Echinodermata and Hemichordata, comprise a major group, the Deuterostomia. Chordates invariably possess a notochord and a dorsal neural tube. Although the origin and evolution of chordates has been studied for more than a century, few authors have intimately discussed taxonomic ranking of the three chordate groups themselves. Accumulating evidence shows that echinoderms and hemichordates form a clade (the Ambulacraria), and that within the Chordata, cephalochordates diverged first, with tunicates and vertebrates forming a sister group. Chordates share tadpole-type larvae containing a notochord and hollow nerve cord, whereas ambulacrarians have dipleurula-type larvae containing a hydrocoel. We propose that an evolutionary occurrence of tadpole-type larvae is fundamental to understanding mechanisms of chordate origin. Protostomes have now been reclassified into two major taxa, the Ecdysozoa and Lophotrochozoa, whose developmental pathways are characterized by ecdysis and trochophore larvae, respectively. Consistent with this classification, the profound dipleurula versus tadpole larval differences merit a category higher than the phylum. Thus, it is recommended that the Ecdysozoa, Lophotrochozoa, Ambulacraria and Chordata be classified at the superphylum level, with the Chordata further subdivided into three phyla, on the basis of their distinctive characteristics. PMID:25232138

Satoh, Noriyuki; Rokhsar, Daniel; Nishikawa, Teruaki

2014-11-01

40

The Fibrobacteres: an important phylum of cellulose-degrading bacteria.  

PubMed

The phylum Fibrobacteres currently comprises one formal genus, Fibrobacter, and two cultured species, Fibrobacter succinogenes and Fibrobacter intestinalis, that are recognised as major bacterial degraders of lignocellulosic material in the herbivore gut. Historically, members of the genus Fibrobacter were thought to only occupy mammalian intestinal tracts. However, recent 16S rRNA gene-targeted molecular approaches have demonstrated that novel centres of variation within the genus Fibrobacter are present in landfill sites and freshwater lakes, and their relative abundance suggests a potential role for fibrobacters in cellulose degradation beyond the herbivore gut. Furthermore, a novel subphylum within the Fibrobacteres has been detected in the gut of wood-feeding termites, and proteomic analyses have confirmed their involvement in cellulose hydrolysis. The genome sequence of F. succinogenes rumen strain S85 has recently suggested that within this group of organisms a "third" way of attacking the most abundant form of organic carbon in the biosphere, cellulose, has evolved. This observation not only has evolutionary significance, but the superior efficiency of anaerobic cellulose hydrolysis by Fibrobacter spp., in comparison to other cellulolytic rumen bacteria that typically utilise membrane-bound enzyme complexes (cellulosomes), may be explained by this novel cellulase system. There are few bacterial phyla with potential functional importance for which there is such a paucity of phenotypic and functional data. In this review, we highlight current knowledge of the Fibrobacteres phylum, its taxonomy, phylogeny, ecology and potential as a source of novel glycosyl hydrolases of biotechnological importance. PMID:22213055

Ransom-Jones, Emma; Jones, David L; McCarthy, Alan J; McDonald, James E

2012-02-01

41

Phylum Nematoda The Nematoda, or roundworms, are a major eukaryotic group and  

E-print Network

Phylum Nematoda The Nematoda, or roundworms, are a major eukaryotic group and display a startling, J. T. Vita and Kelley Thomas. A molecular framework for the phylum Nematoda. Nature, 392, 71­75. 1 which tend to have characteristic host preference, tissue sites and life cycles. Laboratory 7. Nematoda

Schluter, Dolph

42

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

43

Cross-phylum regulatory potential of the ascidian Otx gene in brain development in Drosophila melanogaster  

Microsoft Academic Search

The origin of molecular mechanisms of cephalic development is an intriguing question in evolutionary and developmental biology. Ascidians, positioned near the origin of the phylum Chordata, share a conserved set of anteroposterior patterning genes with vertebrates. Here we report the cross-phylum regulatory potential of the ascidian Otx gene in the development of the Drosophila brain and the head vertex structures.

Yoshitsugu Adachi; Tomoko Nagao; Hidetoshi Saiga; Katsuo Furukubo-Tokunaga

2001-01-01

44

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

E-print Network

A molecular phylogeny of the flagellated fungi (Chytridiomycota) and description of a new phylum (chytrids) is the only phylum of true Fungi that reproduces with motile spores (zoospores). Chytrids orders and families and the majority of flagellated fungi. Within the core chytrid group 11 subclades can

Griffith, Gareth

45

Comparative analysis of 35 basidiomycete genomes reveals diversity and uniqueness of the phylum  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fungi of the phylum Basidiomycota (basidiomycetes), make up some 37% of the described fungi, and are important in forestry, agriculture, medicine, and bioenergy. This diverse phylum includes symbionts, pathogens, and saprobes including wood decaying fungi. To better understand the diversity of this ...

46

Diversity and Habitat Niche Modeling of Candidate Archaeal Phylum Aigarchaeota  

NASA Astrophysics Data System (ADS)

';Aigarchaeota' (formerly known as pSL4 and Hot Water Crenarchaeotic Group I (HWCGI)) is a candidate phylum of Archaea known only by 16S rRNA gene fragments from cultivation-independent microbial surveys and a single composite genome from Candidatus ';Caldiarchaeum subterraneum', an inhabitant of a subterranean gold mine in Japan. Sequences reported in various publications are found exclusively in geothermal settings, but a comprehensive assessment has not yet been performed. We mined public databases for 16S rRNA gene sequences related to known ';Aigarchaeota' and used a combination of approaches to rigorously define the phylogenetic boundaries of the phylum. The analyses supported the proposed relationship between ';Aigarchaeota', Thaumarchaeota, Crenarchaeota, and Korarchaeota in the so-called 'TACK superphylum' and identified ~200 16S rRNA genes and gene fragments belonging to ';Aigarchaeota', including those recovered from terrestrial geothermal systems on several continents (North America, Asia, Africa, Europe, and Oceania) and marine geothermal and subsurface samples in both the Atlantic and Pacific. ';Aigarchaeota' belonged to at least three family- to order-level groups and at least seven genus-level groups. All genus-level groups were recovered from geographically distant locations, suggesting a global distribution within amenable habitats. ';Aigarchaeota'-specific primers for the polymerase chain reaction (PCR) amplification of 16S rRNA genes were designed using SP-Designer and reviewed using the Ribosomal Database Project Probe Match tool. The primers will be used to determine the presence and abundance of ';Aigarchaeota' in a wide variety of samples from terrestrial geothermal systems in the western U.S. and Asia. These phylogenetic data, along with a large geochemical database, will be analyzed using multivariate statistics to develop biogeographic and habitat niche models for ';Aigarchaeota'. This study offers the first coherent view of the distribution and diversity of the ';Aigarchaeota' and lays the groundwork for further inquiry into how environmental factors might control the presence and abundance of this candidate phylum in geothermal environments.

Alba, T. W.; Goertz, G.; Williams, A. J.; Cole, J. K.; Murugapiran, S. K.; Dodsworth, J. A.; Hedlund, B. P.

2013-12-01

47

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

48

A photoactivatable green-fluorescent protein from the phylum Ctenophora  

PubMed Central

Genes for the family of green-fluorescent proteins (GFPs) have been found in more than 100 species of animals, with some species containing six or more copies producing a variety of colours. Thus far, however, these species have all been within three phyla: Cnidaria, Arthropoda and Chordata. We have discovered GFP-type fluorescent proteins in the phylum Ctenophora, the comb jellies. The ctenophore proteins share the xYG chromophore motif of all other characterized GFP-type proteins. These proteins exhibit the uncommon property of reversible photoactivation, in which fluorescent emission becomes brighter upon exposure to light, then gradually decays to a non-fluorescent state. In addition to providing potentially useful optical probes with novel properties, finding a fluorescent protein in one of the earliest diverging metazoans adds further support to the possibility that these genes are likely to occur throughout animals. PMID:20018790

Haddock, Steven H. D.; Mastroianni, Nadia; Christianson, Lynne M.

2010-01-01

49

A photoactivatable green-fluorescent protein from the phylum Ctenophora.  

PubMed

Genes for the family of green-fluorescent proteins (GFPs) have been found in more than 100 species of animals, with some species containing six or more copies producing a variety of colours. Thus far, however, these species have all been within three phyla: Cnidaria, Arthropoda and Chordata. We have discovered GFP-type fluorescent proteins in the phylum Ctenophora, the comb jellies. The ctenophore proteins share the xYG chromophore motif of all other characterized GFP-type proteins. These proteins exhibit the uncommon property of reversible photoactivation, in which fluorescent emission becomes brighter upon exposure to light, then gradually decays to a non-fluorescent state. In addition to providing potentially useful optical probes with novel properties, finding a fluorescent protein in one of the earliest diverging metazoans adds further support to the possibility that these genes are likely to occur throughout animals. PMID:20018790

Haddock, Steven H D; Mastroianni, Nadia; Christianson, Lynne M

2010-04-22

50

Isospora mionectesi sp. nov. (Apicomplexa, Eimeriidae) from the grey-hooded flycatcher, Mionectes rufiventris in Brazil  

Microsoft Academic Search

A new isosporoid coccidian (Apicomplexa, Eimeriidae) species from the grey-hooded flycatcher, Mionectes rufiventris, from Brazil, is reported in the current study. Isospora mionectesi sp. nov. oocysts are ellipsoidal, 28.3 × 21.2 µm, with smooth, bilayered wall, ?1.3 µm. Micropyle and oocyst residuum are\\u000a absent, but one or two polar granules are present. Sporocysts are elongate ellipsoidal, 19.7 × 11.7 µm.

Bruno P. Berto; Walter Flausino; Hermes Ribeiro Luz; Ildemar Ferreira; Carlos Wilson G. Lopes

2009-01-01

51

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. 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.

2013-01-01

52

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

53

The Physiological Tolerance of Two Species of Protozoans  

NSDL National Science Digital Library

Protozoans are single-celled heterotrophic organisms that belong to several Phyla. They vary widely in their morphology and method of reproduction as well as in their ecological niches. The two species that you will study belong to different phyla and obviously have very different habitats. This inquiry examines the differences in pH tolerance between the two species and relates these differences to their respective niches.

BEGIN:VCARD VERSION:2.1 FN:Sergio A. Orminati N:A. Orminati;Sergio ORG:Ranney School REV:2005-04-13 END:VCARD

1995-06-03

54

Phylum Arthropoda Phylum Arthropoda  

E-print Network

of land & flight 2. Metamerism & limbs -allowed incredible limb modifications 3. Short life span & high communication catching prey conveying sperm (spiders) #12;3 Subphylum Chelicerata Pedipalps Subphylum Three classes ·Merostomata ­ relic, 4 species left ·Pycnogonida ­ marine "sea spiders", 1,000 spp

Wagner, Diane

55

Protozoan Acanthamoeba polyphaga as a Potential Reservoir for Campylobacter jejuni  

PubMed Central

We showed by a laboratory experiment that four different Campylobacter jejuni strains are able to infect the protozoan Acanthamoeba polyphaga. C. jejuni cells survived for longer periods when cocultured with amoebae than when grown in culture alone. The infecting C. jejuni cells aggregated in amoebic vacuoles, in which they were seen to be actively moving. Furthermore, a resuscitation of bacterial cultures that were previously negative in culturability tests was observed after reinoculation into fresh amoeba cultures. After spontaneous rupture of the amoebae, C. jejuni could be detected by microscopy and culturability tests. Our results indicate that amoebae may serve as a nonvertebrate reservoir for C. jejuni in the environment. PMID:15691957

Axelsson-Olsson, Diana; Waldenström, Jonas; Broman, Tina; Olsen, Björn; Holmberg, Martin

2005-01-01

56

Disseminated granulomas caused by an unidentified protozoan in sandhill cranes.  

PubMed

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. PMID:521379

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

1979-11-01

57

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

58

New Species of Odonaticola Sarkar et Haldar, 1981 (Apicomplexa: Conoidasida) from Dragonflies (Insecta: Odonata) in West Bengal, India  

Microsoft Academic Search

Summary. Descriptions of four new species of the genus Odonaticola Sarkar et Haldar, 1981 (Apicomplexa: Conoidasida) from dragonflies (Insecta: Odonata) in the family Libellulidae in West Bengal are presented. These include: Odonaticola bradinopyga sp. n. from Bradinopyga geminata; O. aspinosa sp. n. from Crocothemis servilia servilia; O. abhoypura sp. n. from Pantala flavescens and O. amojya sp. n. from C.

Suhritosh BISWAS; Monali CHATTERJEE; Durga P. HALDAR

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

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. PMID:21637385

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

2011-01-01

61

Comparative Genomic Analysis of Multi-Subunit Tethering Complexes Demonstrates an Ancient Pan-Eukaryotic Complement and Sculpting in Apicomplexa  

PubMed Central

Apicomplexa are obligate intracellular parasites that cause tremendous disease burden world-wide. They utilize a set of specialized secretory organelles in their invasive process that require delivery of components for their biogenesis and function, yet the precise mechanisms underpinning such processes remain unclear. One set of potentially important components is the multi-subunit tethering complexes (MTCs), factors increasingly implicated in all aspects of vesicle-target interactions. Prompted by the results of previous studies indicating a loss of membrane trafficking factors in Apicomplexa, we undertook a bioinformatic analysis of MTC conservation. Building on knowledge of the ancient presence of most MTC proteins, we demonstrate the near complete retention of MTCs in the newly available genomes for Guillardiatheta and Bigelowiellanatans. The latter is a key taxonomic sampling point as a basal sister taxa to the group including Apicomplexa. We also demonstrate an ancient origin of the CORVET complex subunits Vps8 and Vps3, as well as the TRAPPII subunit Tca17. Having established that the lineage leading to Apicomplexa did at one point possess the complete eukaryotic complement of MTC components, we undertook a deeper taxonomic investigation in twelve apicomplexan genomes. We observed excellent conservation of the VpsC core of the HOPS and CORVET complexes, as well as the core TRAPP subunits, but sparse conservation of TRAPPII, COG, Dsl1, and HOPS/CORVET-specific subunits. However, those subunits that we did identify appear to be expressed with similar patterns to the fully conserved MTC proteins, suggesting that they may function as minimal complexes or with analogous partners. Strikingly, we failed to identify any subunits of the exocyst complex in all twelve apicomplexan genomes, as well as the dinoflagellate Perkinsus marinus. Overall, we demonstrate reduction of MTCs in Apicomplexa and their ancestors, consistent with modification during, and possibly pre-dating, the move from free-living marine algae to deadly human parasites. PMID:24086721

Klinger, Christen M.; Klute, Mary J.; Dacks, Joel B.

2013-01-01

62

The roles of intramembrane proteases in protozoan parasites?  

PubMed Central

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

2013-01-01

63

Cyclospora: a newly identified protozoan pathogen of man.  

PubMed

A newly recognized protozoan human parasite, Cyclospora spp. has been incriminated as the cause of prolonged diarrhoea. It has been isolated from children, immunocompetent and immunocompromised adults. One hundred and thirty immunocompetent patients, 80 children and 50 adults; their illness was characterized by prolonged watery diarrhoea, were enrolled in this study. Stool sediments were examined as wet mounts and stained by both, modified Ziehl-Neelsen and aniline carbol methyl violet stains. The protozoan pathogen was identified as spherical bodies measuring 9-10 microns in diameter in about 9% and 10% in both children and adult groups respectively. The mean duration of illness was 28 +/- 8 and 37 +/- 12 days and the frequency of stool motions was > 5/day with normal mucosal pattern on colonoscopic studies for adults group. It is concluded from the present study that cyclosporiosis is quite similar to cryptosporidiosis and both oocysts have the affinty to acid fast stain so the present recommendations for all laboratories screening stool for cryptosporidia should measure the oocyst to distinguish between these different parasites and there is obviously a great deal more to learn about this emerging protozoon. PMID:9617058

Nassef, N E; el-Ahl, S A; el-Shafee, O K; Nawar, M

1998-04-01

64

MORN1 Has a Conserved Role in Asexual and Sexual Development across the Apicomplexa?  

PubMed Central

The gene encoding the membrane occupation and recognition nexus protein MORN1 is conserved across the Apicomplexa. In Toxoplasma gondii, MORN1 is associated with the spindle poles, the anterior and posterior rings of the inner membrane complex (IMC). The present study examines the localization of MORN1 during the coccidian development of T. gondii and three Eimeria species (in the definitive host) and erythrocytic schizogony of Plasmodium falciparum. During asexual proliferation, MORN1 is associated with the posterior ring of the IMCs of the multiple daughters forming during T. gondii endopolygeny and schizogony in Eimeria and P. falciparum. Furthermore, the expression of P. falciparum MORN1 protein peaked in late schizogony. These data fit a model with a conserved role for MORN1 during IMC assembly in all variations of asexual development. An important new observation is the reactivity of MORN1 antibody with certain sexual stages in T. gondii and Eimeria species. Here MORN1 is organized as a ring-like structure where the microgametes bud from the microgametocyte while in mature microgametes it is present near the flagellar basal bodies and mitochondrion. These observations suggest a conserved role for MORN1 in both asexual and sexual development across the Apicomplexa. PMID:18310354

Ferguson, David J. P.; Sahoo, Nivedita; Pinches, Robert A.; Bumstead, Janene M.; Tomley, Fiona M.; Gubbels, Marc-Jan

2008-01-01

65

The Meaning of Death: Evolution and Ecology of Apoptosis in Protozoan Parasites  

E-print Network

Review The Meaning of Death: Evolution and Ecology of Apoptosis in Protozoan Parasites Sarah E in a broad range of protozoan parasites offers novel therapeutic tools to treat some of the most serious in unicellular parasites appears counter- intuitive and has proved highly controversial: according

Gardner, Andy

66

Phospholipid biosynthesis in the oyster protozoan parasite, Perkinsus Eric D. Lund, Fu-Lin E. Chu *  

E-print Network

Phospholipid biosynthesis in the oyster protozoan parasite, Perkinsus marinus Eric D. Lund, Fu is a protozoan parasite that causes high mortality in its commercially and ecologically important host, the Eastern oyster Crassostrea virginica. In order to understand the hostÁ/parasite relationship in lipid

Hartley, Troy W.

67

Electing a candidate: a speculative history of the bacterial phylum OP10.  

PubMed

In 1998, a cultivation-independent survey of the microbial community in Obsidian Pool, Yellowstone National Park, detected 12 new phyla within the Domain Bacteria. These were dubbed 'candidate divisions' OP1 to OP12. Since that time the OP10 candidate division has been commonly detected in various environments, usually as part of the rare biosphere, but occasionally as a predominant community component. Based on 16S rRNA gene phylogeny, OP10 comprises at least 12 class-level subdivisions. However, despite this broad ecological and evolutionary diversity, all OP10 bacteria have eluded cultivation until recently. In 2011, two reference species of OP10 were taxonomically validated, removing the phylum from its 'candidate' status. Construction of a highly resolved phylogeny based on 29 universally conserved genes verifies its standing as a unique bacterial phylum. In the following paper we summarize what is known and what is suspected about the newest described bacterial phylum, the Armatimonadetes. PMID:22497633

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

2012-12-01

68

Evidence for the widespread distribution of CRISPR-Cas system in the Phylum Cyanobacteria.  

PubMed

Members of the phylum Cyanobacteria inhabit ecologically diverse environments. However, the CRISPR-Cas (clustered regularly interspaced short palindromic repeats, CRISPR associated genes), an extremely adaptable defense system, has not been surveyed in this phylum. We analyzed 126 cyanobacterial genomes and, surprisingly, found CRISPR-Cas in the majority except the marine subclade (Synechococcus and Prochlorococcus), in which cyanophages are a known force shaping their evolution. Multiple observations of CRISPR loci in the absence of cas1/cas2 genes may represent an early stage of losing a CRISPR-Cas locus. Our findings reveal the widespread distribution of their role in the phylum Cyanobacteria and provide a first step to systematically understanding CRISPR-Cas systems in cyanobacteria. PMID:23628889

Cai, Fei; Axen, Seth D; Kerfeld, Cheryl A

2013-05-01

69

Evidence for the widespread distribution of CRISPR-Cas system in the Phylum Cyanobacteria  

PubMed Central

Members of the phylum Cyanobacteria inhabit ecologically diverse environments. However, the CRISPR-Cas (clustered regularly interspaced short palindromic repeats, CRISPR associated genes), an extremely adaptable defense system, has not been surveyed in this phylum. We analyzed 126 cyanobacterial genomes and, surprisingly, found CRISPR-Cas in the majority except the marine subclade (Synechococcus and Prochlorococcus), in which cyanophages are a known force shaping their evolution. Multiple observations of CRISPR loci in the absence of cas1/cas2 genes may represent an early stage of losing a CRISPR-Cas locus. Our findings reveal the widespread distribution of their role in the phylum Cyanobacteria and provide a first step to systematically understanding CRISPR-Cas systems in cyanobacteria. PMID:23628889

Cai, Fei; Axen, Seth D.; Kerfeld, Cheryl A.

2013-01-01

70

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. PMID:24955977

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

2014-01-01

71

Complete genome sequence of the extremely acidophilic methanotroph isolate V4, Methylacidiphilum infernorum, a representative of the bacterial phylum Verrucomicrobia  

Microsoft Academic Search

BACKGROUND: The phylum Verrucomicrobia is a widespread but poorly characterized bacterial clade. Although cultivation-independent approaches detect representatives of this phylum in a wide range of environments, including soils, seawater, hot springs and human gastrointestinal tract, only few have been isolated in pure culture. We have recently reported cultivation and initial characterization of an extremely acidophilic methanotrophic member of the Verrucomicrobia,

Shaobin Hou; Kira S Makarova; Jimmy HW Saw; Pavel Senin; Benjamin V Ly; Zhemin Zhou; Yan Ren; Jianmei Wang; M. Y. Galperin; Marina V Omelchenko; Yuri I Wolf; Natalya Yutin; Eugene V Koonin; Matthew B Stott; Michelle A Crowe; Angela V Smirnova; Peter F Dunfield; Lu Feng; Lei Wang; Maqsudul Alam

2008-01-01

72

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. PMID:25035337

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

2014-01-01

73

Class-Level Relationships in the Phylum Cnidaria: Evidence from Mitochondrial Genome Structure  

Microsoft Academic Search

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

Diane Bridge; Clifford W. Cunningham; Bernd Schierwater; Rob Desalle; Leo W. Buss

1992-01-01

74

A Molecular Phylogenetic Framework for the Phylum Ctenophora Using 18S rRNA Genes  

Microsoft Academic Search

This paper presents the first molecular phylogenetic analysis of the phylum Ctenophora, by use of 18S ribosomal RNA sequences from most of the major taxa. The ctenophores form a distinct monophyletic group that, based on this gene phylogeny, is most closely related to the cnidarians. Our results suggest that the ancestral ctenophore was tentaculate and cydippid-like and that the presently

Mircea Podar; Steven H. D. Haddock; Mitchell L. Sogin; G. Richard Harbison

2001-01-01

75

Phylum Arthropods Study Material: Demodex folliculorum. 2 slides: section in situ, whole mount.  

E-print Network

, Demodex, Oribates and the like. Parasitiformes includes mesostigmatid mites, which are pri- marily are asymptomatic although in some cases mites cause a dermititis. Other species of Demodex spp. occur in wildlifePhylum Arthropods Study Material: Demodex folliculorum. 2 slides: section in situ, whole mount

Schluter, Dolph

76

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

PubMed

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. PMID:25035337

Lee, Ruth D; Jospin, Guillaume; Coil, David A; Eisen, Jonathan A

2014-01-01

77

Nitrification in activated sludge batch reactors is linked to protozoan grazing of the bacterial population.  

PubMed

Protozoa feed upon free-swimming bacteria and suspended particles inducing flocculation and increasing the turnover rate of nutrients in complex mixed communities. In this study, the effect of protozoan grazing on nitrification was examined in activated sludge in batch cultures maintained over a 14-day period. A reduction in the protozoan grazing pressure was accomplished by using either a dilution series or the protozoan inhibitor cycloheximide. As the dilutions increased, the nitrification rate showed a decline, suggesting that a reduction in protozoan or bacterial concentration may cause a decrease in nitrification potential. In the presence of cycloheximide, where the bacterial concentration was not altered, the rates of production of ammonia, nitrite, and nitrate all were significantly lower in the absence of active protozoans. These results suggest that a reduction in the number or activity of the protozoans reduces nitrification, possibly by limiting the availability of nutrients for slow-growing ammonia and nitrite oxidizers through excretion products. Furthermore, the ability of protozoans to groom the heterotrophic bacterial population in such systems may also play a role in reducing interspecies competition for nitrification substrates and thereby augment nitrification rates. PMID:16391659

Petropoulos, Penny; Gilbride, Kimberley A

2005-09-01

78

Animaux: structures et BIO2525 -Universit d'Ottawa  

E-print Network

'espèces Apicomplexa Sarcomastigophora Ciliophora Arthropoda Mollusca Chordata Playhelminthes Nematoda Annelida · Loup (Canis lupus) Phylum Chordata · �toile de mer Phylum Echinodermata · Moustique Phylum Arthropoda

Blouin-Demers, Gabriel

79

Pathogenesis of infection with Sarcocystis rauschorum (Apicomplexa) in experimentally infected varying lemmings (Dicrostonyx richardsoni).  

PubMed

This study describes the sequential formation of lesions associated with the endogenous development of Sarcocystis rauschorum (Apicomplexa: Sarcocystidae) in varying lemmings, Dicrostonyx richardsoni. Lethal doses of sporocysts (greater than 500) were orally administered to lemmings examined 1-6 days postinoculation (DPI) whereas sublethal doses were administered to lemmings examined subsequently. Transient necrosis and purulent inflammation, in association with precystic merogony, occurred in the liver by 4.5 DPI, peaked at 6 DPI and subsided beginning at 11 DPI with the liver returning to normal by 15 DPI. Cyst formation in skeletal and cardiac muscle was associated with purulent inflammation and sarcolemmal proliferation beginning at 9 DPI. These lesions persisted to 42 DPI. In addition, multifocal nonsuppurative meningoencephalitis was present in six of 11 infected lemmings examined between 11 and 15 DPI. PMID:3119871

Stackhouse, L L; Cawthorn, R J; Brooks, R J

1987-10-01

80

Attenuated reproduction of Strombus gigas by an Apicomplexa: Emeriidae-like parasite in the digestive gland.  

PubMed

An intense and generalized sporozoan infection was detected in every population of the queen conch, Strombus gigas through the Caribbean. In this contribution we establish the relationship between occurrences of an Apicomplexa: Emeriidae-like organism and reproductive activity at San Andres archipelago, Colombia. Occurrence of the parasites was estimated counting the feeding stage Merozoites and cysts Sporozoites at 40× magnification. Nonmetric multidimensional scaling analysis (NMDS) was made to correlate the parasites stages abundance with frequency of the reproductive stages. Gametogenesis and spawning were always low coinciding with high numbers of Merozoites, a positive correlation was established between parasite abundance with reabsorption and undifferentiated stages, and negative correlation was observed between parasite abundance with maturity and spawning stages. The nonmetric multidimensional scaling (NMDS) shows that gametogenesis, maturity and spawning increase as the number of parasites decrease, factor that could be threatening reproduction of S. gigas through the Caribbean. PMID:22484565

Baqueiro Cardenas, Erick; Montero, Jorge; Frenkiel, Liliane; Aldana Aranda, Dalila

2012-07-01

81

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. PMID:24533285

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

2012-01-01

82

Current Developments in the Therapy of Protozoan Infections  

PubMed Central

Protozoan parasites cause serious human and zoonotic infections, including life-threatening diseases such as malaria, African and American trypanosomiasis, and leishmaniasis. These diseases are no more common in the developed world, but together they still threaten about 40% of the world population (WHO estimates). Mortality and morbidity are high in developing countries, and the lack of vaccines makes chemotherapy the only suitable option. However, available antiparasitic drugs are hampered by more or less marked toxic side effects and by the emergence of drug resistance. As the main prevalence of parasitic diseases occurs in the poorest areas of the world, the interest of the pharmaceutical companies in the development of new drugs has been traditionally scarce. The establishment of public-private partnerships focused on tropical diseases is changing this situation, allowing the exploitation of the technological advances that took place during the past decade related to genomics, proteomics, and in silico drug discovery approaches. These techniques allowed the identification of new molecular targets that in some cases are shared by different parasites. In this review we outline the recent developments in the fields of protease and topoisomerase inhibitors, antimicrobial and cell-penetrating peptides, and RNA interference. We also report on the rapidly developing field of new vectors (micro and nano particles, mesoporous materials) that in some cases can cross host or parasite natural barriers and, by selectively delivering new or already in use drugs to the target site, minimize dosage and side effects. PMID:21629507

Zucca, Mario; Savoia, Dianella

2011-01-01

83

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. PMID:17981844

Dávila, Alberto M. R.; Mendes, Pablo N.; Wagner, Glauber; Tschoeke, Diogo A.; Cuadrat, Rafael R. C.; Liberman, Felipe; Matos, Luciana; Satake, Thiago; Ocaña, Kary A. C. S.; Triana, Omar; Cruz, Sérgio M. S.; Jucá, 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

84

Structure and mechanics of the spasmoneme, a biological spring within the protozoan Vorticella convallaria  

E-print Network

Molecular springs have recently emerged as the basis for the fastest and most powerful movements at the cellular level in biology. The spasmoneme of the protozoan, Vorticella convallaria, is a model molecular spring, relying ...

France, Danielle Cook

2007-01-01

85

Rapid methods for the detection of anti-protozoan drug residues.  

E-print Network

??This research describes the development of immunoassays for the detection of residues of three anti-protozoan drugs (coccidiostats), namely, halofuginone,toltrazuril and diclazuril, used in the treatment… (more)

Fitzgerald, Jenny

2012-01-01

86

Molecular & Biochemical Parasitology 133 (2004) 4551 Arachidonic acid synthetic pathways of the oyster protozoan parasite,  

E-print Network

of the oyster protozoan parasite, Perkinsus marinus: evidence for usage of a delta-8 pathway Fu-Lin E. Chua Received 24 June 2003; accepted 28 August 2003 Abstract The meront stage of the oyster protozoan parasite, the parasite first desaturated 18:1(n - 9)-d6 to 18:2(n - 6)-d6 by -12 desaturase, then to 20:2(n - 6)-d6

Hartley, Troy W.

87

Drug resistance in the sexually transmitted protozoan Trichomonas vaginalis.  

PubMed

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, of which metronidazole is the most prescribed, are the only approved, effective drugs to treat trichomoniasis. Resistance against metronidazole is frequently reported and cross-resistance among the family of 5-nitroimidazole drugs is common, leaving no alternative for treatment, with some cases remaining unresolved. The mechanism of metronidazole resistance in T. vaginalis from treatment failures is not well understood, unlike resistance which is developed in the laboratory under increasing metronidazole pressure. In the latter situation, hydrogenosomal function which is involved in activation of the prodrug, metronidazole, is down-regulated. Reversion to sensitivity is incomplete after removal of drug pressure in the highly resistant parasites while clinically resistant strains, so far analysed, maintain their resistance levels in the absence of drug pressure. Although anaerobic resistance has been regarded as a laboratory induced phenomenon, it clearly has been demonstrated in clinical isolates. Pursuit of both approaches will allow dissection of the underlying mechanisms. Many alternative drugs and treatments have been tested in vivo in cases of refractory trichomoniasis, as well as in vitro with some successes including the broad spectrum anti-parasitic drug nitazoxanide. Drug resistance incidence in T. vaginalis appears to be on the increase and improved surveillance of treatment failures is urged. PMID:12974614

Dunne, Rebecca L; Dunn, Linda A; Upcroft, Peter; O'Donoghue, Peter J; Upcroft, Jacqueline A

2003-08-01

88

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

89

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

90

Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes  

PubMed Central

Background The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. Results Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and ‘Turbellaria’) contain methylated cytosines within their genome compartments. Conclusions Collectively, these findings provide the first direct evidence for a functionally conserved and enzymatically active DNA methylation system throughout the Platyhelminthes. Defining how this epigenetic feature shapes phenotypic diversity and development within the phylum represents an exciting new area of metazoan biology. PMID:23837670

2013-01-01

91

Diaspore bank of bryophytes in tropical rain forests: the importance of breeding system, phylum and microhabitat  

Microsoft Academic Search

Diaspore banks are crucial for the maintenance and resilience of plant communities, but diaspore banks of bryophytes remain\\u000a poorly known, especially from tropical ecosystems. This is the first study to focus on the role of diaspore banks of bryophytes\\u000a in tropical rain forests. Our aim was to test whether microhabitat (substrate type) and species traits (breeding system, phylum)\\u000a are important

Adaíses S. Maciel-Silva; Ivany Ferraz Marques Válio; Håkan Rydin

92

Enrichment and Molecular Detection of Denitrifying Methanotrophic Bacteria of the NC10 Phylum?  

PubMed Central

Anaerobic methane oxidation coupled to denitrification was recently assigned to bacteria belonging to the uncultured phylum NC10. In this study, we incubated sediment from a eutrophic ditch harboring a diverse community of NC10 bacteria in a bioreactor with a constant supply of methane and nitrite. After 6 months, fluorescence in situ hybridization showed that NC10 bacteria dominated the resulting population. The enrichment culture oxidized methane and reduced nitrite to dinitrogen gas. We assessed NC10 phylum diversity in the inoculum and the enrichment culture, compiled the sequences currently available for this bacterial phylum, and showed that of the initial diversity, only members of one subgroup had been enriched. The growth of this subgroup was monitored by quantitative PCR and correlated to nitrite-reducing activity and the total biomass of the culture. Together, the results indicate that the enriched subgroup of NC10 bacteria is responsible for anaerobic methane oxidation coupled to nitrite reduction. Due to methodological limitations (a strong bias against NC10 bacteria in 16S rRNA gene clone libraries and inhibition by commonly used stopper material) the environmental distribution and importance of these bacteria could be largely underestimated at present. PMID:19329658

Ettwig, Katharina F.; van Alen, Theo; van de Pas-Schoonen, Katinka T.; Jetten, Mike S. M.; Strous, Marc

2009-01-01

93

Gliding Motility and Por Secretion System Genes Are Widespread among Members of the Phylum Bacteroidetes  

PubMed Central

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

Zhu, Yongtao

2013-01-01

94

Crystal growth of bullet-shaped magnetite in magnetotactic bacteria of the Nitrospirae phylum.  

PubMed

Magnetotactic bacteria (MTB) are known to produce single-domain magnetite or greigite crystals within intracellular membrane organelles and to navigate along the Earth's magnetic field lines. MTB have been suggested as being one of the most ancient biomineralizing metabolisms on the Earth and they represent a fundamental model of intracellular biomineralization. Moreover, the determination of their specific crystallographic signature (e.g. structure and morphology) is essential for palaeoenvironmental and ancient-life studies. Yet, the mechanisms of MTB biomineralization remain poorly understood, although this process has been extensively studied in several cultured MTB strains in the Proteobacteria phylum. Here, we show a comprehensive transmission electron microscopy (TEM) study of magnetic and structural properties down to atomic scales on bullet-shaped magnetites produced by the uncultured strain MYR-1 belonging to the Nitrospirae phylum, a deeply branching phylogenetic MTB group. We observed a multiple-step crystal growth of MYR-1 magnetite: initial isotropic growth forming cubo-octahedral particles (less than approx. 40 nm), subsequent anisotropic growth and a systematic final elongation along [001] direction. During the crystal growth, one major {111} face is well developed and preserved at the larger basal end of the crystal. The basal {111} face appears to be terminated by a tetrahedral-octahedral-mixed iron surface, suggesting dimensional advantages for binding protein(s), which may template the crystallization of magnetite. This study offers new insights for understanding magnetite biomineralization within the Nitrospirae phylum. PMID:25566884

Li, Jinhua; Menguy, Nicolas; Gatel, Christophe; Boureau, Victor; Snoeck, Etienne; Patriarche, Gilles; Leroy, Eric; Pan, Yongxin

2015-02-01

95

Use of Monodispersed, Fluorescently Labeled Bacteria to Estimate In Situ Protozoan Bacterivory †  

PubMed Central

We have developed a procedure for preparing monodispersed, fluorescently labeled bacteria (FLB), which may be used to measure virtually instantaneous rates of protozoan bacterivory in natural waters. FLB can be prepared both from natural bacterioplankton assemblages and from clonal isolates and can be stored in frozen suspension or freeze-dried without apparent loss of fluorescence intensity. They are not toxic to protozoa and can be metabolized to support bacterivorous protozoan growth rates equal to those on the same strain of unstained, viable bacteria. In experiments comparing uptake of FLB with uptake of fluorescent latex microspheres by protozoan assemblages in a salt marsh tidal creek, we found that both pelagic oligotrichous ciliates and phagotrophic flagellates ingested FLB with a frequency 4- to 10-fold greater than they ingested the microspheres. Consequently, it appears that the use of latex microspheres leads to underestimation of protozoan bacterivory and that the FLB technique is superior for estimating instantaneous rates of in situ protozoan grazing on bacterioplankton. Images PMID:16347355

Sherr, Barry F.; Sherr, Evelyn B.; Fallon, Robert D.

1987-01-01

96

Protozoan parasites in group-living primates: testing the biological island hypothesis.  

PubMed

A series of articles by W.J. Freeland published in the 1970s proposed that social organization and behavioral processes were heavily influenced by parasitic infections, which led to a number of intriguing hypotheses concerning how natural selection might act on social factors because of the benefits of avoiding parasite infections. For example, Freeland [1979] showed that all individuals within a given group harbored identical gastrointestinal protozoan faunas, which led him to postulate that social groups were akin to "biological islands" and suggest how this isolation could select specific types of ranging and dispersal patterns. Here, we reexamine the biological island hypothesis by quantifying the protozoan faunas of the same primate species examined by Freeland in the same location; our results do not support this hypothesis. In contrast, we quantified two general changes in protozoan parasite community of primates in the study area of Kibale National Park, Uganda, over the nearly 35 years between sample collections: (1) the colobines found free of parasites in the early 1970s are now infected with numerous intestinal protozoan parasites and (2) groups are no longer biological islands in terms of their protozoan parasites. Whatever the ultimate explanation for these changes, our findings have implications for studies proposing selective forces shaping primate behavior and social organization. PMID:21898515

Chapman, Colin A; Bowman, Dwight D; Ghai, Ria R; Gogarten, Jan F; Goldberg, Tony L; Rothman, Jessica M; Twinomugisha, Dennis; Walsh, Chesley

2012-06-01

97

Two new species of Caryospora Léger, 1904 (Apicomplexa, Eimeriidae) from accipitrid raptors.  

PubMed

Two new species of Coccidia (Apicomplexa: Eimeriidae) are described from European accipitrid raptors (Falconiformes: Accipitridae). Oöcysts of Carvospora aquilae n. sp. found in faeces of the gold eagle Aquila chrysaetos are subspherical to broad ellipsoidal and measure 43 (40-49) x 37.5 (34-39) microm. Polar granule, oöcyst residuum and micropyle are absent. Each oöcyst contains one spherical to subspherical slightly polygonal sporocyst measuring 23.8 (23-25) x 23.3 (22-25) microm. Stieda and substieda bodies are absent. The sporocyst residuum is composed of numerous small granules less than 0.5 microm in diameter dispersed randomly among the sporozoites. Sporulated oöcysts of Carvospora circi n. sp. from faeces of the marsh harrier Circus aeruginosus are widely oval, measuring 24.5 (23-25) x 21.8 (21-24) microm. A polar granule, oöcyst residuum and micropyle are absent. Each oöcyst contains one spherical to subspherical sporocyst measuring 16.2 (15-17) x 15.6 (15-17) microm. A compact granular, spherical to subspherical sporocyst residuum, 10.4 (10-11) x 8.5 (7-9), was present in 76% of measured sporocysts. In 24% of sporocysts the granules of sporocyst residuum were scattered among the sporozoites. PMID:10803432

Volf, J; Koudela, B; Modrý, D

2000-05-01

98

Occurrence of Apicomplexa-like structures in the digestive gland of Strombus gigas throughout the Caribbean.  

PubMed

The queen conch, Strombus gigas, is a marine resource of ecological and economical importance in the Caribbean region. Given its importance in this region, and the critical status of most populations, the reproductive biology of this species has been studied to support management decisions. It was from these studies that a generalized sporozoan infection was detected. This study describes the geographic distribution of a coccidian (Apicomplexa) parasite infecting the digestive gland of S. gigas throughout the Caribbean. The parasite was present in every location sampled. Based on histological analysis, the parasites from all locations are similar and appear to complete their life cycle within the digestive gland. The highest occurrence of the parasites was registered in samples from Puerto Rico (54 parasites per field) and Martinique (45 parasites per field). The lowest incidence was registered on the Mexican coast of Yucatan peninsula, at Alacranes and Chinchorro with 17 parasites per field. Data showed significant differences among sites (Kruskal Wallis H=106.957; p ? 0.05). The abundance of parasites found in the digestive ducts and in the faeces suggests the liberation of parasites to the environment. A gradual decrease in abundance was found from East to West of the Caribbean sea. PMID:20851703

Aranda, Dalila Aldana; Frenkiel, Liliane; Brulé, Thierry; Montero, Jorge; Cárdenas, Erick Baqueiro

2011-02-01

99

Full-parasites: database of full-length cDNAs of apicomplexa parasites, 2010 update.  

PubMed

Full-Parasites (http://fullmal.hgc.jp/) is a transcriptome database of apicomplexa parasites, which include Plasmodium and Toxoplasma species. The latest version of Full-Parasites contains a total of 105,786 EST sequences from 12 parasites, of which 5925 full-length cDNAs have been completely sequenced. Full-Parasites also contain more than 30 million transcription start sites (TSS) for Plasmodium falciparum (Pf) and Toxoplasma gondii (Tg), which were identified using our novel oligo-capping-based protocol. Various types of cDNA data resources were interconnected with our original database functionalities. Specifically, in this update, we have included two unique RNA-Seq data sets consisting of 730 million mapped RNA-Seq tags. One is a dataset of 16 time-lapse experiments of cultured bradyzoite differentiation for Tg. The other dataset includes 31 clinical samples of Pf. Parasite RNA was extracted together with host human RNA, and the extracted mixed RNA was used for RNA sequencing, with the expectation that gene expression information from the host and parasite would be simultaneously represented. By providing the largest unique full-length cDNA and dynamic transcriptome data, Full-Parasites is useful for understanding host-parasite interactions and will help to eventually elucidate how monophyletic organisms have evolved to become parasites by adopting complex life cycles. PMID:21051343

Tuda, Josef; Mongan, Arthur E; Tolba, Mohammed E M; Imada, Mihoko; Yamagishi, Junya; Xuan, Xuenan; Wakaguri, Hiroyuki; Sugano, Sumio; Sugimoto, Chihiro; Suzuki, Yutaka

2011-01-01

100

The red-tailed hawk, Buteo jamaicensis, a native definitive host of Frenkelia microti (Apicomplexa) in North America.  

PubMed

Oral inoculation of prairie voles, Microtus ochrogaster, with coccidian sporocysts isolated from the feces of a red-tailed hawk, Buteo jamaicensis, in Kansas, USA, resulted in formation of Frenkelia microti (Apicomplexa: Sarcocystidae) tissue cysts in the brains of the voles. Five additional isolates of morphologically similar sporocysts collected from red-tailed hawks or other Buteo spp. in Kansas failed to result in detectable infections in rodents. These results are the first to verify that red-tailed hawks are natural definitive host in North America for F. microti. PMID:1548806

Upton, S J; McKown, R D

1992-01-01

101

Eimeria Species (Apicomplexa: Eimeriidae) from Arctic Ground Squirrels (Spermophilus parryii ) and Red Squirrels (Tamiasciurus hudsonicus) in Alaska and in Siberia, Russia  

Microsoft Academic Search

Fecal samples from arctic ground squirrels (Spermophilus parryii) collected in Alaska (n = 90) and Russia (n = 46) and from red squirrels (Tamiasciurus hudsonicus) in Alaska (n = 35) were examined for the presence of Eimeria spp. (Apicomplexa: Eimeriidae). Four species were recovered from arctic ground squirrels, including Eimeria callospermophili (prevalence = 18%), Eimeria cynomysis (23.5%), Eimeria lateralis (19%),

Robert S. Seville; Clint E. Oliver; Andrew J. Lynch; Michelle C. Bryant; Donald W. Duszynski

2005-01-01

102

Distribution and diversity of members of the bacterial phylum Fibrobacteres in environments where cellulose degradation occurs.  

PubMed

The Fibrobacteres phylum contains two described species, Fibrobacter succinogenes and Fibrobacter intestinalis, both of which are prolific degraders of cellulosic plant biomass in the herbivore gut. However, recent 16S rRNA gene sequencing studies have identified novel Fibrobacteres in landfill sites, freshwater lakes and the termite hindgut, suggesting that members of the Fibrobacteres occupy a broader ecological range than previously appreciated. In this study, the ecology and diversity of Fibrobacteres was evaluated in 64 samples from contrasting environments where cellulose degradation occurred. Fibrobacters were detected in 23 of the 64 samples using Fibrobacter genus-specific 16S rRNA gene PCR, which provided their first targeted detection in marine and estuarine sediments, cryoconite from Arctic glaciers, as well as a broader range of environmental samples. To determine the phylogenetic diversity of the Fibrobacteres phylum, Fibrobacter-specific 16S rRNA gene clone libraries derived from 17 samples were sequenced (384 clones) and compared with all available Fibrobacteres sequences in the Ribosomal Database Project repository. Phylogenetic analysis revealed 63 lineages of Fibrobacteres (95% OTUs), with many representing as yet unclassified species. Of these, 24 OTUs were exclusively comprised of fibrobacters derived from environmental (non-gut) samples, 17 were exclusive to the mammalian gut, 15 to the termite hindgut, and 7 comprised both environmental and mammalian strains, thus establishing Fibrobacter spp. as indigenous members of microbial communities beyond the gut ecosystem. The data highlighted significant taxonomic and ecological diversity within the Fibrobacteres, a phylum circumscribed by potent cellulolytic activity, suggesting considerable functional importance in the conversion of lignocellulosic biomass in the biosphere. PMID:25154048

Ransom-Jones, Emma; Jones, David L; Edwards, Arwyn; McDonald, James E

2014-10-01

103

Humanized HLA-DR4 Mice Fed with the Protozoan Pathogen of Oysters Perkinsus Marinus (Dermo) Do Not Develop Noticeable Pathology but Elicit Systemic Immunity  

PubMed Central

Perkinsus marinus (Phylum Perkinsozoa) is a marine protozoan parasite responsible for “Dermo” disease in oysters, which has caused extensive damage to the shellfish industry and estuarine environment. The infection prevalence has been estimated in some areas to be as high as 100%, often causing death of infected oysters within 1–2 years post-infection. Human consumption of the parasites via infected oysters is thus likely to occur, but to our knowledge the effect of oral consumption of P. marinus has not been investigated in humans or other mammals. To address the question we used humanized mice expressing HLA-DR4 molecules and lacking expression of mouse MHC-class II molecules (DR4.EA0) in such a way that CD4 T cell responses are solely restricted by the human HLA-DR4 molecule. The DR4.EA0 mice did not develop diarrhea or any detectable pathology in the gastrointestinal tract or lungs following single or repeated feedings with live P. marinus parasites. Furthermore, lymphocyte populations in the gut associated lymphoid tissue and spleen were unaltered in the parasite-fed mice ruling out local or systemic inflammation. Notably, naïve DR4.EA0 mice had antibodies (IgM and IgG) reacting against P. marinus parasites whereas parasite specific T cell responses were undetectable. Feeding with P. marinus boosted the antibody responses and stimulated specific cellular (IFN?) immunity to the oyster parasite. Our data indicate the ability of P. marinus parasites to induce systemic immunity in DR4.EA0 mice without causing noticeable pathology, and support rationale grounds for using genetically engineered P. marinus as a new oral vaccine platform to induce systemic immunity against infectious agents. PMID:24498105

Kleschenko, Yuliya; Pow-Sang, Luis; Brumeanu, Teodor D.; Villasante, Eileen Franke; Vasta, Gerardo R.; Fernández-Robledo, José-Antonio; Casares, Sofia

2014-01-01

104

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

PubMed Central

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

2012-01-01

105

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

106

Nematopsis gigas n. sp. (Apicomplexa), a parasite of Nerita ascencionis (Gastropoda, Neritidae) from Brazil.  

PubMed

A new species of Nematopsis (Apicomplexa, Porosporidae) is described from the mantle tissues of the seawater gastropod, Nerita ascencionis (Neritidae), collected in the Atlantic North off the coast of "Fernando de Noronha" Island (3 degrees 47' 57'' S, 32 degrees 25' 12'' W) situated about 350 km from the northeast coast of Brazil. Numerous oocysts, each contained in a parasitophorous vacuole, were found in the cytoplasm of phagocytes in the mantle tissue of the host. The phagocytes were surrounded by a thin wall composed of lucent material. The phagocyte cytoplasm contained a nucleus surrounded by numerous vesicles and some dense masses. The oocysts were 21.9 +/- 0.5 microm long, and 11.5 +/- 0.6 microm wide. The oocyst wall was 0.18-0.25 microm thick, and the apical zone contained a micropyle, 1.0-1.2 microm in diameter, covered by a canopy-like operculum about 0.25 microm thick. Externally, the oocyst wall was surrounded by numerous anastomosing microfibrils attached to the wall and extending towards the periphery of the parasitophorous vacuole. Some microfibrils formed a dense complex network that surrounded the oocyst in the middle of the parasitophorous vacuole, which opened only at the apical zone near the external region of the opercular system. On the basis of the data obtained by light and transmission electron microscopy and host specificity, the gregarine Nematopsis gigas is distinguished from the nearest species as a new species. The taxonomic affinities and morphological comparisons with other similar species of the same genus are discussed. PMID:15134258

Azevedo, Carlos; Padovan, Isaíras

2004-01-01

107

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. PMID:24967843

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

2014-01-01

108

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. PMID:23617914

Ostrovsky, Andrew N; Fairbairn, D

2013-01-01

109

Associations between host migration and the prevalence of a protozoan parasite in natural  

E-print Network

Associations between host migration and the prevalence of a protozoan parasite in natural, this host±parasite system provides the opportunity to examine how variation in parasite prevalence relates to host movement patterns. 2. Parasite prevalence was evaluated using 14 790 adult monarchs captured

110

Evidence That Hyaluronidase Is Not Involved in Tissue Invasion of the Protozoan Parasite Entamoeba histolytica  

Microsoft Academic Search

Entamoeba histolytica is the causative agent of human amoe- biasis. Worldwide the protozoan parasite causes about 50 mil- lion cases of colitis or extraintestinal abscesses, and the disease results in at least 50,000 fatalities annually (33). The reproduc- tive forms, the trophozoites, inhabit the cavity of the lower intestine in humans. For unknown reasons, they invade the mucosa of the

ROSA NICKEL; ROBERT STERN; MATTHIAS LEIPPE

2000-01-01

111

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

Microsoft Academic Search

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

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

2011-01-01

112

Protective Immunity Against the Protozoan Leishmania chagasi Is Induced by Subclinical Cutaneous Infection with Virulent  

E-print Network

Protective Immunity Against the Protozoan Leishmania chagasi Is Induced by Subclinical Cutaneous Filho, Stephen M. Beverley,§ and Mary E. Wilson* Protective immunity against Leishmania major is provided by s.c. immunization with a low dose of L. major promastigotes or with dihydrofolate

Beverley, Stephen M.

113

In vitro effects of temperature and salinity on fatty acid synthesis in the oyster protozoan parasite  

E-print Network

In vitro effects of temperature and salinity on fatty acid synthesis in the oyster protozoan in revised form 15 January 2004; accepted 2 February 2004 Abstract The effects of temperature and salinity in vitro at 10, 18 and 28 jC in a salinity of 28 psu and 14, 20 and 28 psu at a temperature of 28 jC using

Hartley, Troy W.

114

Impact of protozoan cell death on parasite-host interactions and pathogenesis  

Microsoft Academic Search

PCD in protozoan parasites has emerged as a fascinating field of parasite biology. This not only relates to the underlying mechanisms and their evolutionary implications but also to the impact on the parasite-host interactions within mammalian hosts and arthropod vectors. During recent years, common functions of apoptosis and autophagy in protozoa and during parasitic infections have emerged. Here, we review

Carsten GK Lüder; Jenny Campos-Salinas; Elena Gonzalez-Rey; Ger van Zandbergen

2010-01-01

115

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...

116

Some protozoan parasites of wild birds from the vicinity of Onderstepoort.  

PubMed

The protozoan parasites of wild birds from the vicinity of Onderstepoort are recorded. New host records for the Republic of South Africa are: Haemoproteus in Threskiornis aethiopicus, Francolinus swainsonii, Columba guinea and Streptopelia senegalensis; Leucocytozoon in Anas erythrorhyncha, Netta Erythrophthalma, C. guinea and Passer domesticus and Plasmodium in Numida meleagris. PMID:810756

Thomas, S E; Dobson, L D

1975-03-01

117

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

118

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

119

Identification of a possible respiratory arsenate reductase in Denitrovibrio acetiphilus, a member of the phylum Deferribacteres.  

PubMed

Denitrovibrio acetiphilus N2460(T) is one of the few members of the phylum Deferribacteres with a sequenced genome. N2460(T) was capable of growing with dimethyl sulfoxide, selenate, or arsenate provided as a terminal electron acceptor, and we identified 15 genes that could possibly encode respiratory reductases for these compounds. The protein encoded by one of these genes, YP_003504839, clustered with respiratory arsenate reductases on a phylogenetic tree. Transcription of the gene for YP_003504839, Dacet_2121, was highly induced when arsenate was provided as a terminal electron acceptor. Dacet_2121 exists in a possible operon that is distinct from the previously characterized respiratory arsenate reductase operon in Shewanella sp. ANA-3. PMID:23955655

Denton, Kyle; Atkinson, Morgan M; Borenstein, Stacey P; Carlson, Alexis; Carroll, Thomas; Cullity, Kristen; Demarsico, Casey; Ellowitz, Daniel; Gialtouridis, Andrea; Gore, Rachel; Herleikson, April; Ling, Albee Yun; Martin, Rachael; McMahan, Katherine; Naksukpaiboon, Piangfan; Seiz, Audrey; Yearwood, Katrina; O'Neill, James; Wiatrowski, Heather

2013-09-01

120

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

121

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

122

Isospora celata n. sp. (Apicomplexa: Eimeriidae) from the orange-crowned warbler Oreothlypis celata (Say) (Passeriformes: Parulidae) in Mexico.  

PubMed

A new coccidian species (Protista: Apicomplexa: Eimeriidae) is described from the orange-crowned warbler Oreothlypis celata (Say) collected in the Nevado de Toluca National Park, Mexico at 3,000 metres above sea level. Isospora celata n. sp. has subspheroidal oöcysts, measuring 28.4 × 26.4 ?m, with smooth, bi-layered wall c.1.2 ?m thick. Micropyle and polar granule are absent, but oöcyst residuum is present as a compact mass. Sporocysts are ovoidal, 18.2 × 12.8 µm. Stieda body knob-like and sub-Stieda body irregular and barely discernible. Sporocyst residuum is composed of granules of different sizes. Sporozoites are vermiform with one refractile body and a nucleus. This is the third description of an isosporoid coccidian infecting a New World warbler. PMID:25301514

Berto, Bruno Pereira; Medina, Juan Pablo; Salgado-Miranda, Celene; García-Conejo, Michele; Janczur, Mariusz Krzysztof; Lopes, Carlos Wilson Gomes; Soriano-Vargas, Edgardo

2014-11-01

123

Cellulase and other polymer-hydrolyzing activities of Trichomitopsis termopsidis, a symbiotic protozoan from termites  

SciTech Connect

Crude extracts of the anaerobic, cellulolytic protozoan Trichomitopsis termopsidis possessed endo-..beta..-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 degrees 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 enyzmes in the nutrition of T. termopsidis is discussed in terms of the natural habitat of this protozoan (the hindgut of wood-eating termites). 31 references.

Odelson, D.A.; Breznak, J.A.

1985-03-01

124

Do you see what I see: Recognition of protozoan parasites by Toll-like receptors  

PubMed Central

Toll-like receptors (TLRs) are important for recognizing a variety of pathogens, including protozoan parasites, and initiating innate immune responses against them. TLRs are localized on the cell surface as well as in the endosome, and are implicated in innate sensing of these parasites. In this review, we will discuss recent findings on the identification of parasite-derived pathogen associated molecular patterns and the TLRs that bind them. The role of these TLRs in initiating the immune response against protozoan parasitic infections in vivo will be presented in the context of murine models of infection utilizing TLR-deficient mice. Additionally, we will explore evidence that TLRs and genetic variants of TLRs may impact the outcome of these parasitic infections in humans. PMID:25383072

Ghosh, Debopam; Stumhofer, Jason S.

2014-01-01

125

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. PMID:12450833

Rønn, Regin; McCaig, Allison E.; Griffiths, Bryan S.; Prosser, James I.

2002-01-01

126

Perkinsus marinus, a protozoan parasite of the Eastern oyster (Crassostrea virginica): effects of temperature on the uptake and  

E-print Network

unit (part per thousand), HPTLC, high performance thin layer chromatography; ECP, extracellular incorporation, lipid metabolism, Chromatography, Parasitic protozoan, Perkinsus marinus, Oyster, Crassostrea liquid chromatography; GLC, gas liquid chromatography; FAME, fatty acid methyl ester; psu, per salinity

Hartley, Troy W.

127

The importance of protozoan bacterivory in a subtropical environment (Lobo-Broa Reservoir, SP, Brazil).  

PubMed

This study evaluated the importance of heterotrophic nanoflagellates (HNF) and ciliates bacterivory in a mesotrophic subtropical environment (Lobo-Broa Reservoir, Brazil) by the quantification of their ingestion rates. The in situ experiments using fluorescently labelled bacteria (FLB) were carried out bimonthly over one year (three surveys in the dry season and three in the rainy one) at the sub-surface of two sampling points that have different trophic degrees. The ingestion rates for both ciliates and HNF were higher in the meso-eutrophic region (point 2) due to the higher water temperatures, which accelerate the metabolism of protozoans and the higher bacteria densities. Concerning total protozoan bacterivory, the HNF had the greatest grazing impact on bacterial community, especially the HNF <5 µm. The data showed that HNF grazing, in addition to regulating the bacteria abundance, also induced changes to the bacterial community structure, such as increasing size and numbers of bacterial filaments. The ciliates were also important to the system bacterivory, especially in point 2, where there were high densities and ingestion rates. The protozoan bottom-up control was more important in the dry season and the top-down control was more important in the rainy season, so, these two forces are equally important to the bacterial abundance regulation in this reservoir in an annual basis. PMID:25296204

Mansano, A S; Hisatugo, K F; Hayashi, L H; Regali-Seleghim, M H

2014-08-01

128

The Regulation of CD4+ T Cell Responses during Protozoan Infections  

PubMed Central

CD4+ T cells are critical for defense against protozoan parasites. Intracellular protozoan parasite infections generally require the development of a Th1 cell response, characterized by the production of IFN? and TNF that are critical for the generation of microbicidal molecules by phagocytes, as well as the expression of cytokines and cell surface molecules needed to generate cytolytic CD8+ T cells that can recognize and kill infected host cells. Over the past 25?years, much has been learnt about the molecular and cellular components necessary for the generation of Th1 cell responses, and it has become clear that these responses need to be tightly controlled to prevent disease. However, our understanding of the immunoregulatory mechanisms activated during infection is still not complete. Furthermore, it is apparent that although these mechanisms are critical to prevent inflammation, they can also promote parasite persistence and development of disease. Here, we review how CD4+ T cells are controlled during protozoan infections and how these regulatory mechanisms can influence parasite growth and disease outcome. PMID:25352846

Engwerda, Christian R.; Ng, Susanna S.; Bunn, Patrick T.

2014-01-01

129

Macrophage biology and their activation by protozoan-derived glycosylphosphatidylinositol anchors and hemozoin.  

PubMed

Abstract :? Despite recent advances in medical technology and a global effort to improve public health and hygiene, parasitic infections remain a major health and economic burden worldwide. The World Health Organization estimates that about 1/3 of the world's population is currently infected with a soil-transmitted helminth, and millions more suffer from diseases caused by protozoan parasites including Plasmodium, Trypanosoma, and Leishmania species. Due to the selective pressure applied by parasitic and other infections, animals have evolved an intricate immune system; however, the current worldwide prevalence of parasitic infections clearly indicates that these pathogens have adapted equally well. Thus, developing a better understanding of the host-parasite relationship, particularly by focusing on the host immune response and the mechanisms by which parasites evade this response, is a critical first step in mitigating the detrimental effects of parasitic diseases. Macrophages are critical contributors during the host response to protozoan parasites, and the success or failure of these cells often tips the balance in favor of the host or parasite. Herein, we briefly discuss macrophage biology and provide an update on our current understanding of how these cells recognize glycosylphosphatidylinositol anchors from protozoan parasites as well as malarial hemozoin. PMID:25265042

Aldridge, Jerry R; Vogel, Ian A

2014-12-01

130

Complete mitochondrial genome sequence of Urechis caupo, a representative of the phylum Echiura  

PubMed Central

Background Mitochondria contain small genomes that are physically separate from those of nuclei. Their comparison serves as a model system for understanding the processes of genome evolution. Although hundreds of these genome sequences have been reported, the taxonomic sampling is highly biased toward vertebrates and arthropods, with many whole phyla remaining unstudied. This is the first description of a complete mitochondrial genome sequence of a representative of the phylum Echiura, that of the fat innkeeper worm, Urechis caupo. Results This mtDNA is 15,113 nts in length and 62% A+T. It contains the 37 genes that are typical for animal mtDNAs in an arrangement somewhat similar to that of annelid worms. All genes are encoded by the same DNA strand which is rich in A and C relative to the opposite strand. Codons ending with the dinucleotide GG are more frequent than would be expected from apparent mutational biases. The largest non-coding region is only 282 nts long, is 71% A+T, and has potential for secondary structures. Conclusions Urechis caupo mtDNA shares many features with those of the few studied annelids, including the common usage of ATG start codons, unusual among animal mtDNAs, as well as gene arrangements, tRNA structures, and codon usage biases. PMID:15369601

Boore, Jeffrey L

2004-01-01

131

Distinction of cell types in Dicyema japonicum (phylum Dicyemida) by expression patterns of 16 genes.  

PubMed

Dicyemids (phylum Dicyemida) are endoparasites, or endosymbionts, typically found in the renal sac of benthic cephalopod molluscs. The body organization of dicyemids is very simple, consisting of only 9 to 41 somatic cells. Dicyemids appear to have no differentiated tissues. Although categorization of somatic cells, to some types, is based on differences in the pattern of cilia and their position in the body, whether or not these cells are functionally different remains to be revealed. To provide insight into the functional differentiation, we performed whole mount in situ hybridization (WISH) to detect expression patterns of 16 genes, i.e., aquaglyceroporin, F-actin capping protein, aspartate aminotransferase, cathepsin-L-like cysteine peptidase, Ets domain-containing protein, glucose transporter, glucose-6-phosphate 1-dehydrogenase, glycine transporter, Hsp 70, Hsp 90, isocitrate dehydrogenase subunit alpha, Rad18, serine hydroxymethyltransferase, succinate-CoA ligase, valosin-containing protein, and 14-3-3 protein. In certain genes, regional specific expression patterns were observed among somatic cells of vermiform stages and infusoriform larvae of dicyemids. The WISH analyses also revealed that the Ets domain-containing protein and Rad18 are molecular markers for agametes. PMID:21506842

Ogino, Kazutoyo; Tsuneki, Kazuhiko; Furuya, Hidetaka

2011-08-01

132

The expression of tubulin and tektin genes in dicyemid mesozoans (Phylum: Dicyemida).  

PubMed

Dicyemid mesozoans (Phylum Dicyemida) are endoparasites (or endosymbionts) that typically are found in the renal sac of benthic cephalopod mollusks such as octopuses and cuttlefishes. Adult dicyemids likely adhere to the renal appendage of hosts via cilia of calotte peripheral cells. These cilia seem to be continuously worn away in the interaction between the dicyemids and the epidermal cells of host renal appendages. We cloned 4 cDNAs and genes, alpha-tubulin, beta-tubulin, tektin B, and tektin C, which are thought to play a key role in ciliogenesis, from Dicyema japonicum, and studied expression patterns of these genes by whole-mount in situ hybridization. We detected coexpression of these genes in the calotte peripheral cells, but not in the trunk peripheral cells. This suggests that regeneration and turnover of cilia continuously occur in the calotte. In vermiform and infusoriform embryos, we also detected coexpression patterns of these genes, which might correlate with ciliogenesis during the embryogenesis. We also predicted the secondary structure and the coiled-coil regions of dicyemid tektins. PMID:17626353

Ogino, Kazutoyo; Tsuneki, Kazuhiko; Furuya, Hidetaka

2007-06-01

133

Global patterns of abundance, diversity and community structure of the Aminicenantes (candidate phylum OP8).  

PubMed

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. PMID:24637619

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

2014-01-01

134

First genomic insights into members of a candidate bacterial phylum responsible for wastewater bulking  

PubMed Central

Filamentous cells belonging to the candidate bacterial phylum KSB3 were previously identified as the causative agent of fatal filament overgrowth (bulking) in a high-rate industrial anaerobic wastewater treatment bioreactor. Here, we obtained near complete genomes from two KSB3 populations in the bioreactor, including the dominant bulking filament, using differential coverage binning of metagenomic data. Fluorescence in situ hybridization with 16S rRNA-targeted probes specific for the two populations confirmed that both are filamentous organisms. Genome-based metabolic reconstruction and microscopic observation of the KSB3 filaments in the presence of sugar gradients indicate that both filament types are Gram-negative, strictly anaerobic fermenters capable of non-flagellar based gliding motility, and have a strikingly large number of sensory and response regulator genes. We propose that the KSB3 filaments are highly sensitive to their surroundings and that cellular processes, including those causing bulking, are controlled by external stimuli. The obtained genomes lay the foundation for a more detailed understanding of environmental cues used by KSB3 filaments, which may lead to more robust treatment options to prevent bulking. PMID:25650158

Ohashi, Akiko; Parks, Donovan H.; Yamauchi, Toshihiro; Tyson, Gene W.

2015-01-01

135

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. PMID:24637619

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

2014-01-01

136

Bacteria of the Candidate Phylum TM7 are Prevalent in Acidophilic Nitrifying Sequencing-Batch Reactors.  

PubMed

Laboratory-scale acidophilic nitrifying sequencing-batch reactors (ANSBRs) were constructed by seeding with sewage-activated sludge and cultivating with ammonium-containing acidic mineral medium (pH 4.0) with or without a trace amount of yeast extract. In every batch cycle, the pH varied between 2.7 and 4.0, and ammonium was completely converted to nitrate. Attempts to detect nitrifying functional genes in the fully acclimated ANSBRs by PCR with previously designed primers mostly gave negative results. 16S rRNA gene-targeted PCR and a subsequent denaturating gradient gel electrophoresis analysis revealed that a marked change occurred in the bacterial community during the overall period of operation, in which members of the candidate phylum TM7 and the class Gammaproteobacteria became predominant at the fully acclimated stage. This result was fully supported by a 16S rRNA gene clone library analysis, as the major phylogenetic groups of clones detected (>5% of the total) were TM7 (33%), Gammaproteobacteria (37%), Actinobacteria (10%), and Alphaproteobacteria (8%). Fluorescence in situ hybridization with specific probes also demonstrated the prevalence of TM7 bacteria and Gammaproteobacteria. These results suggest that previously unknown nitrifying microorganisms may play a major role in ANSBRs; however, the ecophysiological significance of the TM7 bacteria predominating in this process remains unclear. PMID:25241805

Hanada, Akiko; Kurogi, Takashi; Minh Giang, Nguyen; Yamada, Takeshi; Kamimoto, Yuki; Kiso, Yoshiaki; Hiraishi, Akira

2014-09-20

137

Single-cell genomics reveals the lifestyle of Poribacteria, a candidate phylum symbiotically associated with marine sponges  

Microsoft Academic Search

In this study, we present a single-cell genomics approach for the functional characterization of the candidate phylum Poribacteria, members of which are nearly exclusively found in marine sponges. The microbial consortia of the Mediterranean sponge Aplysina aerophoba were singularized by fluorescence-activated cell sorting, and individual microbial cells were subjected to phi29 polymerase-mediated ‘whole-genome amplification’. Pyrosequencing of a single amplified genome

Alexander Siegl; Janine Kamke; Thomas Hochmuth; Jörn Piel; Michael Richter; Chunguang Liang; Thomas Dandekar; Ute Hentschel

2011-01-01

138

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

SciTech Connect

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 and discuss the findings in light of physiological data. E. minutum has all genes required for uptake and fermentation of sugars via the Embden-Meyerhof pathway, including several hydrogenases, and an unusual peptide degradation pathway comprising transamination reactions and leading to the formation of alanine, which is excreted in substantial amounts. The presence of genes encoding lipopolysaccharide biosynthesis and the presence of a pathway for peptidoglycan formation are consistent with ultrastructural evidence of a Gram-negative cell envelope. Even though electron micrographs showed no cell appendages, the genome encodes many genes putatively involved in pilus assembly. We assigned some to a type II secretion system, but the function of 60 pilE-like genes remains unknown. Numerous genes with hypothetical functions, e.g., polyketide synthesis, non-ribosomal peptide synthesis, antibiotic transport, and oxygen stress protection, indicate the presence of hitherto undiscovered physiological traits. Comparative analysis of 22 concatenated single-copy marker genes corroborated the status of Elusimicrobia (formerly TG1) as a separate phylum in the bacterial domain, which was so far based only on 16S rRNA sequence analysis.

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

2009-02-01

139

Protozoan Grazing, Bacterial Activity, and Mineralization in Two-Stage Continuous Cultures  

PubMed Central

In two-stage continuous cultures, at bacterial concentrations, biovolumes, and growth rates similar to values found in Lake Vechten, ingestion rates of heterotrophic nanoflagellates (HNAN) increased from 2.3 bacteria HNAN?1 · h?1 at a growth rate of 0.15 day?1 to 9.2 bacteria · HNAN?1 · h?1 at a growth rate of 0.65 day?1. On a yeast extract medium with a C/N/P ratio of 100:15:1.2 (Redfield ratio), a mixed bacterial population showed a yield of 18% (C/C) and a specific carbon content of 211 fg of C · ?m?3. The HNAN carbon content and yield were estimated at 127 fg of C · ?m?3 and 47% (C/C). Although P was not growth limiting, HNAN accelerated the mineralization of PO4-P from dissolved organic matter by 600%. The major mechanism of P remineralization appeared to be direct consumption of bacteria by HNAN. N mineralization was performed mainly (70%) by bacteria but was increased 30% by HNAN. HNAN did not enhance the decomposition of the relatively mineral-rich dissolved organic matter. An accelerated decomposition of organic carbon by protozoa may be restricted to mineral-poor substrates and may be explained mainly by protozoan nutrient regeneration. Growth and grazing in the cultures were compared with methods for in situ estimates. Thymidine incorporation by actively growing bacteria yielded an empirical conversion factor of 1.1 × 1018 bacteria per mol of thymidine incorporated into DNA. However, nongrowing bacteria also showed considerable incorporation. Protozoan grazing was found to be accurately measured by uptake of fluorescently labeled bacteria, whereas artificial fluorescent microspheres were not ingested, and selective prokaryotic inhibitors blocked not only bacterial growth but also protozoan grazing. PMID:16347801

Bloem, Jaap; Starink, Mathieu; Bär-Gilissen, Marie-José B.; Cappenberg, Thomas E.

1988-01-01

140

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. PMID:22110378

de Dios Rosado, Juan; Rodriguez-Sosa, Miriam

2011-01-01

141

Evidence of Gene Diminution During the Formation of the Macronucleus in the Protozoan, Stylonychia*  

PubMed Central

The course of events by which a macronucleus is formed from a micronucleus after conjugation in the ciliated protozoan, Stylonychia, suggests that genetic diminution may occur. This idea is supported by determinations of the density profiles and melting curves for micro- and macronuclear DNAs. Macronuclear DNA consists of a single density component and melts as if it were a single component. Micronuclear DNA consists of four or more density components and melts as if it were a mixture of several DNAs of different base compositions. These data indicate that at least 60% of the micronuclear DNA components are absent from the macronuclear DNA. Images PMID:4500545

Bostock, C. J.; Prescott, D. M.

1972-01-01

142

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. PMID:22763649

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

2012-01-01

143

Insights into the metabolism, lifestyle and putative evolutionary history of the novel archaeal phylum 'Diapherotrites'.  

PubMed

The archaeal phylum 'Diapherotrites' was recently proposed based on phylogenomic analysis of genomes recovered from an underground water seep in an abandoned gold mine (Homestake mine in Lead, SD, USA). Here we present a detailed analysis of the metabolic capabilities and genomic features of three single amplified genomes (SAGs) belonging to the 'Diapherotrites'. The most complete of the SAGs, Candidatus 'Iainarchaeum andersonii' (Cand. IA), had a small genome (?1.24?Mb), short average gene length (822?bp), one ribosomal RNA operon, high coding density (?90.4%), high percentage of overlapping genes (27.6%) and low incidence of gene duplication (2.16%). Cand. IA genome possesses limited catabolic capacities that, nevertheless, could theoretically support a free-living lifestyle by channeling a narrow range of substrates such as ribose, polyhydroxybutyrate and several amino acids to acetyl-coenzyme A. On the other hand, Cand. IA possesses relatively well-developed anabolic capabilities, although it remains auxotrophic for several amino acids and cofactors. Phylogenetic analysis suggests that the majority of Cand. IA anabolic genes were acquired from bacterial donors via horizontal gene transfer. We thus propose that members of the 'Diapherotrites' have evolved from an obligate symbiotic ancestor by acquiring anabolic genes from bacteria that enabled independent biosynthesis of biological molecules previously acquired from symbiotic hosts. 'Diapherotrites' 16S rRNA genes exhibit multiple mismatches with the majority of archaeal 16S rRNA primers, a fact that could be responsible for their observed rarity in amplicon-generated data sets. The limited substrate range, complex growth requirements and slow growth rate predicted could be responsible for its refraction to isolation. PMID:25083931

Youssef, Noha H; Rinke, Christian; Stepanauskas, Ramunas; Farag, Ibrahim; Woyke, Tanja; Elshahed, Mostafa S

2015-02-01

144

Influence of Plant Polymers on the Distribution and Cultivation of Bacteria in the Phylum Acidobacteria ? †  

PubMed Central

Members of the phylum Acidobacteria are among the most abundant bacteria in soil. Although they have been characterized as versatile heterotrophs, it is unclear if the types and availability of organic resources influence their distribution in soil. The potential for organic resources to select for different acidobacteria was assessed using molecular and cultivation-based approaches with agricultural and managed grassland soils in Michigan. The distribution of acidobacteria varied with the carbon content of soil: the proportion of subdivision 4 sequences was highest in agricultural soils (ca. 41%) that contained less carbon than grassland soils, where the proportions of subdivision 1, 3, 4, and 6 sequences were similar. Either readily oxidizable carbon or plant polymers were used as the sole carbon and energy source to isolate heterotrophic bacteria from these soils. Plant polymers increased the diversity of acidobacteria cultivated but decreased the total number of heterotrophs recovered compared to readily oxidizable carbon. Two phylogenetically novel Acidobacteria strains isolated on the plant polymer medium were characterized. Strains KBS 83 (subdivision 1) and KBS 96 (subdivision 3) are moderate acidophiles with pH optima of 5.0 and 6.0, respectively. Both strains grew slowly (? = 0.01 h?1) and harbored either 1 (strain KBS 83) or 2 (strain KBS 96) copies of the 16S rRNA encoding gene—a genomic characteristic typical of oligotrophs. Strain KBS 83 is a microaerophile, growing optimally at 8% oxygen. These metabolic characteristics help delineate the niches that acidobacteria occupy in soil and are consistent with their widespread distribution and abundance. PMID:21097594

Eichorst, Stephanie A.; Kuske, Cheryl R.; Schmidt, Thomas M.

2011-01-01

145

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. PMID:24327776

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

2013-01-01

146

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. PMID:16199669

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

147

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. PMID:24058169

Portman, Neil; Foster, Christie; Walker, Giselle

2014-01-01

148

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. PMID:24885094

2014-01-01

149

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae) from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) of Round Island, Mauritius: an endangered parasite?  

Microsoft Academic Search

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae), C. durelli n. sp., is described from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) from Round Island, Mauritius. Six of 11 hosts were infected. Oöcysts are spherical to\\u000a subspherical, 19.2 × 18.2 (17.5–21 × 16–21) ?m, n = 20, and have a shape index (mean length\\/mean width) of 1.05 (1.02–1.09).\\u000a The bi-layered wall is

Peter DaszakStanley; Stanley J. Ball; Daniel G. Streicker; Carl G. Jones; Keith R. Snow

2011-01-01

150

[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

151

Revision of Geneiorhynchus Schneider, 1875 (Apicomplexa: Eugregarinida: Actinocephalidae: Acanthosporinae) with Recognition of Four New Species of Geneiorhynchus and Description of Geneiorhynchus manifestus n. sp. Parasitizing Naiads of the Green Darner, Anax junius (Odonata: Aeshnidae) in the Texas Big Thicket  

Microsoft Academic Search

Geneiorhynchus manifestus n. sp. (Apicomplexa: Eugregarinida) is described from the naiads of Anax junius (Odonata: Aeshnidae) collected from the Big Sandy Creek Unit of the Big Thicket National Preserve, Polk County, Texas, U.S.A. The genus Geneiorhynchus is revised and its constituent species reviewed. Descriptions are provided for 2 previously named species, Geneiorhynchus monnieri from naiads of Libellula depressa (Odonata: Libellulidae)

Richard E. Clopton; Tamara J. Cook; Jerry L. Cook

2007-01-01

152

Proteasome activity is required for the stage-specific transformation of a protozoan parasite  

PubMed Central

A prominent feature of the life cycle of intracellular parasites is the profound morphological changes they undergo during development in the vertebrate and invertebrate hosts. In eukaryotic cells, most cytoplasmic proteins are degraded in proteasomes. Here, we show that the transformation in axenic medium of trypomastigotes of Trypanosoma cruzi into amastigote-like organisms, and the intracellular development of the parasite from amastigotes into trypomastigotes, are prevented by lactacystin, or by a peptide aldehyde that inhibits proteasome function. Clasto-lactacystin, an inactive analogue of lactacystin, and cell-permeant peptide aldehyde inhibitors of T. cruzi cysteine proteinases have no effect. We have also identified the 20S proteasomes from T. cruzi as a target of lactacystin in vivo. Our results document the essential role of proteasomes in the stage-specific transformation of a protozoan. PMID:8920878

1996-01-01

153

Changes in trophic structure of a freshwater protozoan community subjected to cadmium.  

PubMed

The development of protozoan communities in laboratory microecosystems has been studied in order to observe the effect of cadmium on the trophic structure and dynamics of these communities. The effect of cadmium was evident on the species richness, density, and biomass. The most sensitive parameters seem to be biomass and species richness. In the controls, the trophic structure of the community was defined for bacterivore-detritivore, photautotroph, algivore, and in low proportion for nonselective species. In the fractions with cadmium there was a decrease in diversity in each trophic group; the bacterivore-detritivore and photosynthetic species were the most affected. Also, there was an appearance of saprotroph species. Species belonging to the control and others exclusively pertaining to microecosystems with cadmium were observed. PMID:7691521

Fernández-Leborans, G; Novillo-Villajos, A

1993-06-01

154

[A checklist of protozoan and metazoan parasites of the burbot (Lota lota)].  

PubMed

The parasite fauna of the burbot (Lota lota) within its natural range is reviewed. The sent paper summarizes the data on parasites of the burbot from water bodies of Eurasia and North America, based on published monographs, reviewed journals, scientific reports, conference contributions, and PhD theses. The checklist includes all protozoan and metazoan parasites of the burbot. A total of 242 parasite species/taxa were recorded in the burbot (Ki-netoplastomonada--4, Parasitomonada--3, Coccidiomorpha--1. Microsporidea--3, Myxosporidia--35, Pleurostomata--1. Cyrtostomata--3, Peritricha--20. Protozoa incertae sedis--1. Monogenea--8, Cestoda--23, Digenea--50. Nematoda--36, Acanthocephala--28, Hirudinea--11. Bivalvia--5, Crustacea--10). Most parasites belong to digenean trematodes. Most of these species (183 species/taxa) were recorded on Eurasian and only 92--in North America fishes. Several parasite species recorded from the burbot are discussed in relation to host specificity and their geographical distribution. PMID:22586925

Zhokhov, A E; Pugacheva, M N

2012-01-01

155

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. PMID:22634346

Coutinho-Silva, Robson; Ojcius, David M.

2014-01-01

156

Germination, Growth, and Sporulation of Bacillus thuringiensis subsp. israelensis in Excreted Food Vacuoles of the Protozoan Tetrahymena pyriformis  

Microsoft Academic Search

Spores of Bacillus thuringiensis subsp. israelensis and their toxic crystals are bioencapsulated in the protozoan Tetrahymena pyriformis, in which the toxin remains stable. Each T. pyriformis cell concentrates the spores and crystals in its food vacuoles, thus delivering them to mosquito larvae, which rapidly die. Vacuoles containing undigested material are later excreted from the cells. The fate of spores and

ROBERT MANASHEROB; EITAN BEN-DOV; ARIEH ZARITSKY; EV BARAK

1998-01-01

157

Impact of protozoan grazing on nitrification and the ammonia- and nitrite-oxidizing bacterial communities in activated sludge.  

PubMed

In activated sludge, protozoa feed on free-swimming bacteria and suspended particles, inducing flocculation and increasing the turnover rate of nutrients. In this study, the effect of protozoan grazing on nitrification rates under various conditions in municipal activated sludge batch reactors was examined, as was the spatial distribution of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) within the activated sludge. The reactors were monitored for ammonia, nitrite, nitrate, and total nitrogen concentrations, and bacterial numbers in the presence and absence of cycloheximide (a protozoan inhibitor), allylthiourea (an inhibitor of ammonia oxidation), and EDTA (a deflocculating agent). The accumulations of nitrate, nitrite, and ammonia were lower in batches without than with protozoa grazing. Inhibition of ammonia oxidation also decreased the amount of nitrite and nitrate accumulation. Inhibiting protozoan grazing along with ammonia oxidation further decreased the amounts of nitrite and nitrate accumulated. Induction of deflocculation led to high nitrate accumulation, indicating high levels of nitrification; this effect was lessened in the absence of protozoan grazing. Using fluorescent in situ hybridization and confocal laser scanning microscopy, AOB and NOB were found clustered within the floc, and inhibiting the protozoa, inhibiting ammonia oxidation, or inducing flocculation did not appear to lower the number of AOB and NOB present or affect their position within the floc. These results suggest that the AOB and NOB are present but less active in the absence of protozoa. PMID:17668014

Pogue, Amy J; Gilbride, Kimberley A

2007-05-01

158

Toxoplasmosis Toxoplasma gondii is a protozoan parasite that can infect many animals, including humans. It belongs to  

E-print Network

or transplant therapy or individuals that are positive for HIV. Biology Toxoplasma gondii is a protozoan transfusion or organ transplantation . · transplacentally from mother to fetus . In the human host, the parasites form tissue cysts, most commonly in skeletal muscle, myocardium, brain, and eyes; these cysts may

Wood, Marcelo A.

159

Benthic bacterial production and protozoan predation in a silty freshwater environment.  

PubMed

The interrelation of heterotrophic bacteria with bacterivorous protists has been widely studied in pelagic environments, but data on benthic habitats, especially in freshwater systems, are still scarce. We present a seasonal study focusing on bacterivory by heterotrophic nanoflagellates (HNF) and ciliates in the silty sediment of a temperate macrophyte-dominated oxbow lake. From January 2001 to February 2002 we monitored the standing stock of bacteria and protozoa, bacterial secondary production (BSP, (3)H-thymidine, and (14)C-leucine incorporation), and grazing rates of HNF and ciliates on bacteria (FLB uptake) in the oxic sediment of the investigated system. BSP ranged from 470 to 4050 micro g C L(-1) wet sediment h(-1). The bacterial compartment turned out to be highly dynamic, indicated by population doubling times (0.6-10.0 d), which were comparable to those in the water column of the investigated system. Yet, the control mechanisms acting upon the bacterial population led to a relative constancy of bacterial standing stock during a year. Ingestion rates of protozoan grazers were 0-20.0 bacteria HNF(-1) h(-1) and 0-97.6 bacteria ciliate(-1) h(-1). HNF and ciliates together cropped 0-14 (mean 4)% of BSP, indicating that they did not significantly contribute to benthic bacterial mortality during any period of the year. The low impact of protozoan grazing was due to the low numbers of HNF and ciliates in relation to bacteria (1.8-3.5 x 10(4) bacteria HNF(-1), 0.9-3.1 x 10(6) bacteria ciliate(-1)). Thus, grazing by HNF and ciliates could be ruled out as a parameter regulating bacterial standing stock or production in the sediment of the investigated system, but the factors responsible for the limitation of benthic protistan densities and the fate of benthic BSP remained unclear. PMID:12739079

Wieltschnig, C; Fischer, U R; Kirschner, A K T; Velimirov, B

2003-07-01

160

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

SciTech Connect

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, acetate amendments initially promoted the growth of metal-reducing Geobacter species followed by the growth of sulfate-reducers, as previously observed. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater prior to the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the amoeboid 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; Giloteaux, L.; Williams, Kenneth H.; Wrighton, Kelly C.; Wilkins, Michael J.; Thompson, Courtney A.; Roper, Thomas J.; Long, Philip E.; Lovley, Derek

2013-07-28

161

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. PMID:23549915

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

162

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. PMID:15247413

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

2004-01-01

163

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. PMID:16332876

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

2005-01-01

164

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. PMID:23921581

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

2013-01-01

165

A Unique Pool of Compatible Solutes on Rhodopirellula baltica, Member of the Deep-Branching Phylum Planctomycetes  

PubMed Central

The intracellular accumulation of small organic solutes was described in the marine bacterium Rhodopirellula baltica, which belongs to the globally distributed phylum Planctomycetes whose members exhibit an intriguing lifestyle and cell morphology. Sucrose, ?-glutamate, trehalose and mannosylglucosylglycerate (MGG) are the main solutes involved in the osmoadaptation of R. baltica. The ratio and total intracellular organic solutes varied significantly in response to an increase in salinity, temperature and nitrogen content. R. baltica displayed an initial response to both osmotic and thermal stresses that includes ?-glutamate accumulation. This trend was followed by a rather unique and complex osmoadaptation mechanism characterized by a dual response to sub-optimal and supra-optimal salinities. A reduction in the salinity to sub-optimal conditions led primarily to the accumulation of trehalose. In contrast, R. baltica responded to salt stress mostly by increasing the intracellular levels of sucrose. The switch between the accumulation of trehalose and sucrose was by far the most significant effect caused by increasing the salt levels of the medium. Additionally, MGG accumulation was found to be salt- as well as nitrogen-dependent. MGG accumulation was regulated by nitrogen levels replacing ?-glutamate as a K+ counterion in nitrogen-poor environments. This is the first report of the accumulation of compatible solutes in the phylum Planctomycetes and of the MGG accumulation in a mesophilic organism. PMID:23826385

Mingote, Ana; Lamosa, Pedro; da Costa, Milton S.; Costa, Joana

2013-01-01

166

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

PubMed

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. PMID:23921581

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

2013-01-01

167

A Unique Pool of Compatible Solutes on Rhodopirellula baltica, Member of the Deep-Branching Phylum Planctomycetes.  

PubMed

The intracellular accumulation of small organic solutes was described in the marine bacterium Rhodopirellula baltica, which belongs to the globally distributed phylum Planctomycetes whose members exhibit an intriguing lifestyle and cell morphology. Sucrose, ?-glutamate, trehalose and mannosylglucosylglycerate (MGG) are the main solutes involved in the osmoadaptation of R. baltica. The ratio and total intracellular organic solutes varied significantly in response to an increase in salinity, temperature and nitrogen content. R. baltica displayed an initial response to both osmotic and thermal stresses that includes ?-glutamate accumulation. This trend was followed by a rather unique and complex osmoadaptation mechanism characterized by a dual response to sub-optimal and supra-optimal salinities. A reduction in the salinity to sub-optimal conditions led primarily to the accumulation of trehalose. In contrast, R. baltica responded to salt stress mostly by increasing the intracellular levels of sucrose. The switch between the accumulation of trehalose and sucrose was by far the most significant effect caused by increasing the salt levels of the medium. Additionally, MGG accumulation was found to be salt- as well as nitrogen-dependent. MGG accumulation was regulated by nitrogen levels replacing ?-glutamate as a K(+) counterion in nitrogen-poor environments. This is the first report of the accumulation of compatible solutes in the phylum Planctomycetes and of the MGG accumulation in a mesophilic organism. PMID:23826385

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

2013-01-01

168

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. PMID:19270135

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

2009-01-01

169

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. PMID:21191098

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

2011-01-01

170

The human gut and groundwater harbor non-photosynthetic bacteria belonging to a new candidate phylum sibling to Cyanobacteria  

PubMed Central

Cyanobacteria were responsible for the oxygenation of the ancient atmosphere; however, the evolution of this phylum is enigmatic, as relatives have not been characterized. Here we use whole genome reconstruction of human fecal and subsurface aquifer metagenomic samples to obtain complete genomes for members of a new candidate phylum sibling to Cyanobacteria, for which we propose the designation ‘Melainabacteria’. Metabolic analysis suggests that the ancestors to both lineages were non-photosynthetic, anaerobic, motile, and obligately fermentative. Cyanobacterial light sensing may have been facilitated by regulators present in the ancestor of these lineages. The subsurface organism has the capacity for nitrogen fixation using a nitrogenase distinct from that in Cyanobacteria, suggesting nitrogen fixation evolved separately in the two lineages. We hypothesize that Cyanobacteria split from Melainabacteria prior or due to the acquisition of oxygenic photosynthesis. Melainabacteria remained in anoxic zones and differentiated by niche adaptation, including for symbiosis in the mammalian gut. DOI: http://dx.doi.org/10.7554/eLife.01102.001 PMID:24137540

Di Rienzi, Sara C; Sharon, Itai; Wrighton, Kelly C; Koren, Omry; Hug, Laura A; Thomas, Brian C; Goodrich, Julia K; Bell, Jordana T; Spector, Timothy D; Banfield, Jillian F; Ley, Ruth E

2013-01-01

171

Protozoan Bacterivory and Escherichia coli Survival in Drinking Water Distribution Systems  

PubMed Central

The development of bacterial communities in drinking water distribution systems leads to a food chain which supports the growth of macroorganisms incompatible with water quality requirements and esthetics. Nevertheless, very few studies have examined the microbial communities in drinking water distribution systems and their trophic relationships. This study was done to quantify the microbial communities (especially bacteria and protozoa) and obtain direct and indirect proof of protozoan feeding on bacteria in two distribution networks, one of GAC water (i.e., water filtered on granular activated carbon) and the other of nanofiltered water. The nanofiltered water-supplied network contained no organisms larger than bacteria, either in the water phase (on average, 5 × 107 bacterial cells liter?1) or in the biofilm (on average, 7 × 106 bacterial cells cm?2). No protozoa were detected in the whole nanofiltered water-supplied network (water plus biofilm). In contrast, the GAC water-supplied network contained bacteria (on average, 3 × 108 cells liter?1 in water and 4 × 107 cells cm?2 in biofilm) and protozoa (on average, 105 cells liter?1 in water and 103 cells cm?2 in biofilm). The water contained mostly flagellates (93%), ciliates (1.8%), thecamoebae (1.6%), and naked amoebae (1.1%). The biofilm had only ciliates (52%) and thecamoebae (48%). Only the ciliates at the solid-liquid interface of the GAC water-supplied network had a measurable grazing activity in laboratory test (estimated at 2 bacteria per ciliate per h). Protozoan ingestion of bacteria was indirectly shown by adding Escherichia coli to the experimental distribution systems. Unexpectedly, E. coli was lost from the GAC water-supplied network more rapidly than from the nanofiltered water-supplied network, perhaps because of the grazing activity of protozoa in GAC water but not in nanofiltered water. Thus, the GAC water-supplied network contained a functional ecosystem with well-established and structured microbial communities, while the nanofiltered water-supplied system did not. The presence of protozoa in drinking water distribution systems must not be neglected because these populations may regulate the autochthonous and allochthonous bacterial populations. PMID:9435076

Sibille, I.; Sime-Ngando, T.; Mathieu, L.; Block, J. C.

1998-01-01

172

Phylogenetic relationships within the class Anthozoa (phylum Cnidaria) based on nuclear 18S rDNA sequences.  

PubMed

Taxonomic relationships within the corals and anemones (Phylum Cnidaria: Class Anthozoa) are based upon few morphological characters. The significance of any given character is debatable, and there is little fossil record available for deriving evolutionary relationships. We analyzed complete 18S ribosomal sequences to examine subclass-level and ordinal-level organization within the Anthozoa. We suggest that the Subclass Ceriantipatharia is not an evolutionarily relevant grouping. The Order Corallimorpharia appears paraphyletic and closely related to the Order Scleractinia. The 18S rRNA gene may be insufficient for establishing robust phylogenetic hypotheses concerning the specific relationships of the Corallimorpharia and the Ceriantharia and the branching sequence for the orders within the Hexacorallia. The 18S rRNA gene has sufficient phylogenetic signal, however, to distinguish among the major groupings within the Class Anthozoa, and we use this information to suggest relationships for the enigmatic taxa Dactylanthus and Dendrobrachia. PMID:10603268

Berntson, E A; France, S C; Mullineaux, L S

1999-11-01

173

Sunxiuqinia elliptica gen. nov., sp. nov., a member of the phylum Bacteroidetes isolated from sediment in a sea cucumber farm.  

PubMed

Three novel aerobic, elliptic bacteria, designated DQHS4(T), DQHS8 and DQHS15, were isolated from sediment of a seashore pond for sea cucumber culture in Jimo, Qingdao, on the east coast of China. Cells were Gram-, oxidase- and catalase-negative. All three strains grew at 15-42 °C, pH 5-9 and NaCl concentrations between 0.5 and 10%. DNA-DNA hybridization experiments revealed high (>85%) relatedness among the three novel isolates and suggested that the strains constitute a single species. Comparative 16S rRNA gene sequence analysis indicated that these bacteria had less than 90% similarity to all described species of the phylum Bacteroidetes; the closest relative of the three isolates was Prolixibacter bellariivorans F2(T), sharing only 89.6% sequence similarity. The major cellular fatty acids were iso-C(17:0) 3-OH (19.8-20.0%), iso-C(15:0) (16.9-17.3%), anteiso-C(17:1) B and/or iso-C(17:1) I (7.4-8.7%), C(17:0) 2-OH (8.4%), anteiso-C(15:0) (8.2-8.6%) and C(17:1)?6c (5.6-6.0%). The major respiratory quinone was menaquinone-7 (MK-7) and the DNA G+C content was 41.8-43.5 mol%. Based on the distinct phylogenetic position and the combination of genotypic, phenotypic and chemotaxonomic characteristics, these three strains were considered to represent a novel species of a new genus in the phylum Bacteroidetes, for which the name Sunxiuqinia elliptica gen. nov., sp. nov. is proposed. The type strain of Sunxiuqinia elliptica is DQHS4(T) (=CGMCC 1.9156(T) =NCCB 100301(T) =LMG 25367(T)). PMID:21257687

Qu, Lingyun; Zhu, Fengling; Hong, Xuguang; Gao, Wei; Chen, Junhui; Sun, Xiuqin

2011-12-01

174

The Meaning of Death: Evolution and Ecology of Apoptosis in Protozoan Parasites  

PubMed Central

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

2011-01-01

175

Global Distribution, Public Health and Clinical Impact of the Protozoan Pathogen Cryptosporidium  

PubMed Central

Cryptosporidium spp. are coccidians, oocysts-forming apicomplexan protozoa, which complete their life cycle both in humans and animals, through zoonotic and anthroponotic transmission, causing cryptosporidiosis. The global burden of this disease is still underascertained, due to a conundrum transmission modality, only partially unveiled, and on a plethora of detection systems still inadequate or only partially applied for worldwide surveillance. In children, cryptosporidiosis encumber is even less recorded and often misidentified due to physiological reasons such as early-age unpaired immunological response. Furthermore, malnutrition in underdeveloped countries or clinical underestimation of protozoan etiology in developed countries contribute to the underestimation of the worldwide burden. Principal key indicators of the parasite distribution were associated to environmental (e.g., geographic and temporal clusters, etc.) and host determinants of the infection (e.g., age, immunological status, travels, community behaviours). The distribution was geographically mapped to provide an updated picture of the global parasite ecosystems. The present paper aims to provide, by a critical analysis of existing literature, a link between observational epidemiological records and new insights on public health, and diagnostic and clinical impact of cryptosporidiosis. PMID:20706669

Putignani, Lorenza; Menichella, Donato

2010-01-01

176

Assembly-History Dynamics of a Pitcher-Plant Protozoan Community in Experimental Microcosms  

PubMed Central

Background History drives community assembly through differences both in density (density effects) and in the sequence in which species arrive (sequence effects). Density effects arise from predictable population dynamics, which are free of history, but sequence effects are due to a density-free mechanism, arising solely from the order and timing of immigration events. Few studies have determined how components of immigration history (timing, number of individuals, frequency) alter local dynamics to determine community assembly, beyond addressing when immigration history produces historically contingent assembly. Methods/Findings We varied density and sequence effects independently in a two-way factorial design to follow community assembly in a three-species aquatic protozoan community. A superior competitor, Colpoda steinii, mediated alternative community states; early arrival or high introduction density allowed this species to outcompete or suppress the other competitors (Poterioochromonas malhamensis and Eimeriidae gen. sp.). Multivariate analysis showed that density effects caused greater variation in community states, whereas sequence effects altered the mean community composition. Conclusions A significant interaction between density and sequence effects suggests that we should refine our understanding of priority effects. These results highlight a practical need to understand not only the “ingredients” (species) in ecological communities but their “recipes” as well. PMID:22880069

Kadowaki, Kohmei; Inouye, Brian D.; Miller, Thomas E.

2012-01-01

177

Photodynamic therapy in the cattle protozoan Tritrichomonas foetus cultivated on superhydrophilic carbon nanotube.  

PubMed

Superhydrophilic vertically aligned carbon nanotubes (VACNT-O2) were used for the first time as scaffolds for photodynamic therapy (PDT) to induce inhibition of cell division in eukaryotic cells. VACNT-O2 scaffolds were produced on Ti substrates using plasma enhanced chemical vapor deposition technique and functionalized by oxygen plasma. Scanning electron microscopy (SEM) analysis was performed to characterize the surface changes of the protozoan and interaction with VACNT-O2. Characterization of lipid and total protein expression was performed with protozoa that were or not treated with PDT. Quantification of protein was conducted using Qubit fluorometer and separated on a polyacrylamide gel. SEM analysis showed the release of lipid vesicles by protozoa after the PDT. These vesicles were characterized by the PKH26 fluorescent probe. The results demonstrated a greater amount of protein released after PDT than in the control. When analyzing the protein material in polyacrylamide gel, a significant protein expression of approximately 65 kDa was found. A model identified the programmed death of Tritrichomonas foetus after the PDT was also proposed. PMID:24433902

Machado, Susane Moreira; Pacheco-Soares, Cristina; Marciano, Fernanda Roberta; Lobo, Anderson Oliveira; da Silva, Newton Soares

2014-03-01

178

Incidence and Persistence of Zoonotic Bacterial and Protozoan Pathogens in a Beef Cattle Feedlot Runoff Control–Vegetative Treatment System  

Microsoft Academic Search

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. Th e 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

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

2007-01-01

179

Scyphidia Tholiformis, a Peritrichous Protozoan Found on the Gills and External Surfaces of Micropterus Dolomieu and Micropterus Salmoides  

Microsoft Academic Search

Scyphidia tholiformis is an urn-shaped peritrichous protozoan measuring about 59 microns in length and 35 microns in width. It possesses a double row of cilia about one-third of the distance from the anterior end of the body and has a large scopula which is variable in shape and provides a large surface for attachment. The macronucleus is long and band-like,

Eugene W. Surber

1943-01-01

180

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

181

4-Methylumbelliferyl-?-N-Acetylglucosaminide Hydrolysis by a High-Affinity Enzyme, a Putative Marker of Protozoan Bacterivory  

PubMed Central

Hydrolysis of an artificial fluorogenic substrate, 4-methylumbelliferyl-?-N-acetylglucosaminide, has been studied in a monoculture predator-prey system with either a flagellate (Bodo saltans) or a ciliate (Cyclidium sp.) fed upon pure bacterial culture (Aeromonas hydrophila or Alcaligenes xylosoxidans). Aeromonas hydrophila produced a low-affinity ?-N-acetylglucosaminidase-like enzyme (Km, ?100 ?mol liter-1) but Alcaligenes xylosoxidans did not. Inoculation of both bacterial strains with bacterivorous protozoa induced the occurrence of another, high-affinity, ?-N-acetylglucosaminidase-like enzyme (Km, <0.5 ?mol liter-1). The latter enzyme showed significant, close correlations with total grazing rates of both B. saltans (r2 = 0.96) and Cyclidium sp. (r2 = 0.89) estimated by using uptake of fluorescently labelled bacteria. Further significant correlations between several protozoan parameters and kinetic parameters of this enzyme suggest its likely protozoan origin. If both types of enzyme occurred together, they could be satisfactorily distinguished by using kinetic data analysis. Hence, measurements of ?-N-acetylglucosaminidase-like activities might be promising to use to improve estimations of protozoan bacterivory. PMID:16349049

Vrba, Jaroslav; Šimek, Karel; Nedoma, Ji?í; Hartman, Petr

1993-01-01

182

[Protozoans in superficial waters and faecal samples of individuals of rural populations of the Montes municipality, Sucre state, Venezuela].  

PubMed

In Sucre state, the Manzanares river is threatened by domestic, agricultural and industrial activities, becoming an environmental risk factor for its inhabitants. In this sense, the presence of protozoans in superficial waters of tributaries of the Manzanares river (Orinoco river, Quebrada Seca, San Juan river), Montes municipality, Sucre state, as well as the analysis of faecal samples from inhabitants of towns bordering these tributaries were evaluated. We collected faecal and water samples from may 2006 through april 2007. The superficial water samples were processed after centrifugation by the direct examination and floculation, using lugol, modified Kinyoun and trichromic colorations. Fecal samples where analyzed by direct examination with physiological saline solution and the modified Ritchie concentration method and using the other colorations techniques above mentioned. The most frequently observed protozoans in superficial waters in the three tributaries were: Amoebas, Blastocystis sp, Endolimax sp., Chilomastix sp. and Giardia sp. Whereas in faecal samples, Blastocystis hominis, Endolimax nana and Entaomeba coli had the greatest frequencies in the three communities. The inhabitants of Orinoco La Peña turned out to be most susceptible to these parasitic infections (77.60%), followed by San Juan River (46.63%) and Quebrada Seca (39.49%). The presence of pathogenic and nonpathogenic protozoans in superficial waters demonstrates the faecal contamination of the tributaries, representing a constant focus of infection for their inhabitants, inferred by the observation of the same species in both types of samples. PMID:21365874

Mora, Leonor; Martínez, Indira; Figuera, Lourdes; Segura, Merlyn; Del Valle, Guilarte

2010-12-01

183

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

184

Aggregata (Protozoa: Apicomplexa) infection in the common octopus Octopus vulgaris from the West Mediterranean Sea: The infection rates and possible effect of faunistic, environmental and ecological factors  

NASA Astrophysics Data System (ADS)

Prevalence and distribution of the coccidian parasite Aggregata octopiana (Protozoa: Apicomplexa) in common octopus (Octopus vulgaris) in the Mediterranean Spanish coasts were studied. A total of 114 octopuses were sampled from 30 geographic sectors by trawl fleet, and whitish macroscopic oocysts typical of A. octopiana infection were recorded in 96% of octopuses in the digestive tract and mainly in intestine and spiral caecum. The univariate analysis showed that lesion extension varied according to specific octopus, environmental and faunistic variables. A subsequent multivariable analysis indicated that the risk of macroscopic lesions in the caecum was greater in males compared to females, in octopuses living in deeper compared to shallower waters and in hauls where the crustacean Pagurus excavatus was present. The study provides further evidence of the abundance of A. octopiana in octopus ecosystems urging for further studies to evaluate its health impact. The combined abundance of infected octopuses and P. excavatus merits attention.

Mayo-Hernández, E.; Barcala, E.; Berriatua, E.; García-Ayala, A.; Muñoz, P.

2013-10-01

185

Eimeria species (Apicomplexa: Eimeriidae) from arctic ground squirrels (Spermophilus parryii) and red squirrels (Tamiasciurus hudsonicus) in Alaska and in Siberia, Russia.  

PubMed

Fecal samples from arctic ground squirrels (Spermophilus parryii) collected in Alaska (n = 90) and Russia (n = 46) and from red squirrels (Tamiasciurus hudsonicus) in Alaska (n = 35) were examined for the presence of Eimeria spp. (Apicomplexa: Eimeriidae). Four species were recovered from arctic ground squirrels, including Eimeria callospermophili (prevalence = 18%), Eimeria cynomysis (23.5%), Eimeria lateralis (19%), and Eimeria morainensis (77%). A single species, Eimeria tamiasciuri (91%), was recovered from red squirrels. Eimerians recovered from arctic ground squirrels represent new host records, and the single species from red squirrels is a new geographic record. Alaskan arctic ground squirrel prevalence was higher for E. callospermophili (Alaska = 22% vs. Russia = 9%), E. cynomysis (34% vs. 2%), and E. lateralis (27% vs. 4%), but not E. morainensis (78% vs. 76%). PMID:17089755

Seville, Robert S; Oliver, Clint E; Lynch, Andrew J; Bryant, Michelle C; Duszynski, Donald W

2005-08-01

186

Phylum Arthropoda -Lec. 4 Phylum Arthropoda  

E-print Network

Class Pycnogonida Class Arachnida Subphylum Mandibulata Class Crustacea Class Myriapoda Class Insecta of Snodgrass 1930-1950s Three classes ·Crustacea ­ shrimps, lobsters, etc. 45,000 spp. ·Myriapoda ­ centipedes. Not clear how the mandibulates are related No marine fossil record for Myriapoda & Insecta appear ~ 100

Wagner, Diane

187

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

188

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. PMID:23029590

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

2012-01-01

189

Protozoan predation is differentially affected by motility of enteric pathogens in water vs. sediments.  

PubMed

Survival of enteric bacteria in aquatic habitats varies depending upon species, strain, and environmental pressures, but the mechanisms governing their fate are poorly understood. Although predation by protozoa is a known, top-down control mechanism on bacterial populations, its influence on the survival of fecal-derived pathogens has not been systematically studied. We hypothesized that motility, a variable trait among pathogens, can influence predation rates and bacterial survival. We compared the survival of two motile pathogens of fecal origin by culturing Escherichia coli O157 and Salmonella enterica Typhimurium. Each species had a motile and non-motile counterpart and was cultured in outdoor microcosms with protozoan predators (Tetrahymena pyriformis) present or absent. Motility had a significant, positive effect on S. enterica levels in water and sediment in the presence or absence of predators. In contrast, motility had a significant negative effect on E. coli O157 levels in sediment, but did not affect water column levels. The presence/absence of protozoa consistently accounted for a greater proportion of the variability in bacterial levels (>95 %) than in bacterial motility (<4 %) in the water column. In sediments, however, motility was more important than predation for both bacteria. Calculations of total CFU/microcosm showed decreasing bacterial concentrations over time under all conditions except for S. enterica in the absence of predation, which increased ?0.5-1.0 log over 5 days. These findings underscore the complexity of predicting the survival of enteric microorganisms in aquatic habitats, which has implications for the accuracy of risk assessment and modeling of water quality. PMID:24952019

Wanjugi, Pauline; Harwood, Valerie J

2014-11-01

190

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. PMID:22347391

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

191

Toxoplasma gondii infection in humans in China  

PubMed Central

Toxoplasmosis is a zoonotic infection of humans and animals, caused by the opportunistic protozoan Toxoplasma gondii, a parasite belonging to the phylum Apicomplexa. Infection in pregnant women may lead to abortion, stillbirth or other serious consequences in newborns. Infection in immunocompromised patients can be fatal if not treated. On average, one third of people are chronically infected worldwide. Although very limited information from China has been published in the English journals, T. gondii infection is actually a significant human health problem in China. In the present article, we reviewed the clinical features, transmission, prevalence of T. gondii infection in humans in China, and summarized genetic characterizations of reported T. gondii isolates. Educating the public about the risks associated with unhealthy food and life style habits, tracking serological examinations to special populations, and measures to strengthen food and occupational safety are discussed. PMID:21864327

2011-01-01

192

Lytic Cycle of Toxoplasma gondii  

PubMed Central

Toxoplasma gondii is an obligate intracellular pathogen within the phylum Apicomplexa. This protozoan parasite is one of the most widespread, with a broad host range including many birds and mammals and a geographic range that is nearly worldwide. While infection of healthy adults is usually relatively mild, serious disease can result in utero or when the host is immunocompromised. This sophisticated eukaryote has many specialized features that make it well suited to its intracellular lifestyle. In this review, we describe the current knowledge of how the asexual tachyzoite stage of Toxoplasma attaches to, invades, replicates in, and exits the host cell. Since this process is closely analogous to the way in which viruses reproduce, we refer to it as the Toxoplasma “lytic cycle.” PMID:10974128

Black, Michael W.; Boothroyd, John C.

2000-01-01

193

Complete genome sequence of the extremely acidophilic methanotroph isolate V4, Methylacidiphilum infernorum, a representative of the bacterial phylum Verrucomicrobia  

PubMed Central

Background The phylum Verrucomicrobia is a widespread but poorly characterized bacterial clade. Although cultivation-independent approaches detect representatives of this phylum in a wide range of environments, including soils, seawater, hot springs and human gastrointestinal tract, only few have been isolated in pure culture. We have recently reported cultivation and initial characterization of an extremely acidophilic methanotrophic member of the Verrucomicrobia, strain V4, isolated from the Hell's Gate geothermal area in New Zealand. Similar organisms were independently isolated from geothermal systems in Italy and Russia. Results We report the complete genome sequence of strain V4, the first one from a representative of the Verrucomicrobia. Isolate V4, initially named "Methylokorus infernorum" (and recently renamed Methylacidiphilum infernorum) is an autotrophic bacterium with a streamlined genome of ~2.3 Mbp that encodes simple signal transduction pathways and has a limited potential for regulation of gene expression. Central metabolism of M. infernorum was reconstructed almost completely and revealed highly interconnected pathways of autotrophic central metabolism and modifications of C1-utilization pathways compared to other known methylotrophs. The M. infernorum genome does not encode tubulin, which was previously discovered in bacteria of the genus Prosthecobacter, or close homologs of any other signature eukaryotic proteins. Phylogenetic analysis of ribosomal proteins and RNA polymerase subunits unequivocally supports grouping Planctomycetes, Verrucomicrobia and Chlamydiae into a single clade, the PVC superphylum, despite dramatically different gene content in members of these three groups. Comparative-genomic analysis suggests that evolution of the M. infernorum lineage involved extensive horizontal gene exchange with a variety of bacteria. The genome of M. infernorum shows apparent adaptations for existence under extremely acidic conditions including a major upward shift in the isoelectric points of proteins. Conclusion The results of genome analysis of M. infernorum support the monophyly of the PVC superphylum. M. infernorum possesses a streamlined genome but seems to have acquired numerous genes including those for enzymes of methylotrophic pathways via horizontal gene transfer, in particular, from Proteobacteria. Reviewers This article was reviewed by John A. Fuerst, Ludmila Chistoserdova, and Radhey S. Gupta. PMID:18593465

Hou, Shaobin; Makarova, Kira S; Saw, Jimmy HW; Senin, Pavel; Ly, Benjamin V; Zhou, Zhemin; Ren, Yan; Wang, Jianmei; Galperin, Michael Y; Omelchenko, Marina V; Wolf, Yuri I; Yutin, Natalya; Koonin, Eugene V; Stott, Matthew B; Mountain, Bruce W; Crowe, Michelle A; Smirnova, Angela V; Dunfield, Peter F; Feng, Lu; Wang, Lei; Alam, Maqsudul

2008-01-01

194

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. PMID:25019377

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

2014-01-01

195

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

PubMed

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. PMID:22717097

Chalmers, Iain W; Hoffmann, Karl F

2012-09-01

196

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

197

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

PubMed

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 indicates that the replicate assemblies represent a new candidate phylum within the domain Archaea referred to here as 'Geoarchaeota' or '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 carbon monoxide dehydrogenase complex likely used for energy conservation. Moreover, this novel population contains genes involved in the 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-oxide mats of YNP, and will provide insight regarding the evolution of Archaea in early Earth environments that may have important analogs active in YNP today. PMID:23151644

Kozubal, Mark A; Romine, Margaret; Jennings, Ryan deM; Jay, Zack J; Tringe, Susannah G; Rusch, Doug B; Beam, Jacob P; McCue, Lee Ann; Inskeep, William P

2013-03-01

198

Seasonal dominance of CL500-11 bacterioplankton (phylum Chloroflexi) in the oxygenated hypolimnion of Lake Biwa, Japan.  

PubMed

Uncultured bacteria affiliated with the CL500-11 cluster (phylum Chloroflexi) were first reported from the oxygenated hypolimnion of Crater Lake (USA) as a predominant bacterioplankton, although this dominance has not been reported in other environments. In this study, we showed that CL500-11 is also dominant in the oxygenated hypolimnion of Lake Biwa (Japan) and followed its spatiotemporal succession using fluorescent in situ hybridization. CL500-11 cells were almost absent [< 1% of 4',6-diamidino-2-phenylindole (DAPI)-stained cells] at the beginning of the stratification period, dominated (> 10% of DAPI-stained cells; maximum = 16.5%) in the hypolimnion during the stratification period, and decreased to below the detection limit with the collapse of the thermocline. This pattern was observed over two annual cycles. A longitudinal assessment also showed that CL500-11 was the dominant bacterium in the hypolimnion over the whole lake, but was generally undetectable in the stratified epilimnion. These data suggest that CL500-11 is acclimated to the oxygenated hypolimnion and is a potentially important component of the pelagic biogeochemical cycling of the lake. A comparative analysis of 16S rRNA gene sequences revealed that almost all CL500-11 sequences previously deposited in the database were detected from hypolimnion or holomictic water in deep oxic freshwater lakes, suggesting that the bacteria may form one of the common lineages residing in an aerobic hypolimnetic niche. PMID:22809435

Okazaki, Yusuke; Hodoki, Yoshikuni; Nakano, Shin-ichi

2013-01-01

199

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

PubMed Central

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 indicates that the replicate assemblies represent a new candidate phylum within the domain Archaea referred to here as ‘Geoarchaeota' or ‘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 carbon monoxide dehydrogenase complex likely used for energy conservation. Moreover, this novel population contains genes involved in the 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-oxide mats of YNP, and will provide insight regarding the evolution of Archaea in early Earth environments that may have important analogs active in YNP today. PMID:23151644

Kozubal, Mark A; Romine, Margaret; Jennings, Ryan deM; Jay, Zack J; Tringe, Susannah G; Rusch, Doug B; Beam, Jacob P; McCue, Lee Ann; Inskeep, William P

2013-01-01

200

Rubritalea marina gen. nov., sp. nov., a marine representative of the phylum 'Verrucomicrobia', isolated from a sponge (Porifera).  

PubMed

A marine bacterium, strain Pol012(T), was isolated from the Mediterranean sponge Axinella polypoides and subsequently characterized as belonging to subphylum 1 of the phylum 'Verrucomicrobia'. Strain Pol012(T) was non-motile, Gram-negative, coccoid or rod-shaped and red in colour. The menaquinones MK-8 and MK-9 were detected. The G+C content of the genomic DNA was 50.9 mol%. Growth was possible at temperatures between 8 and 30 degrees C and at pH values between 6.8 and 8.2. The closest cultured relative of strain Pol012(T) was Akkermansia muciniphila (83 % sequence similarity), while the closest environmental 16S rRNA gene sequence was the marine clone Arctic96BD-2 (95 % sequence similarity). Strain Pol012(T) is the first marine pure-culture representative of 'Verrucomicrobia' subphylum 1 and represents a novel genus and species, for which the name Rubritalea marina gen. nov., sp. nov. is proposed. The type strain is Pol012(T) (=DSM 177716(T)=CIP 108984(T)). PMID:16957108

Scheuermayer, Matthias; Gulder, Tobias A M; Bringmann, Gerhard; Hentschel, Ute

2006-09-01

201

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. PMID:24805255

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

2014-01-01

202

Phylogenetic relationships within the class Oligohymenophorea, phylum Cilophora, inferred from the complete small subunit rRNA gene sequences of Colpidium campylum, Glaucoma chattoni , and Opisthonecta henneguyi  

Microsoft Academic Search

Summary Phylogenetic relationships within the class Oligohymenophorea, phylum Ciliophora, were investigated by determining the complete small subunit rRNA (SSrRNA) gene sequences for the hymenostomesColpidium campylum, Glaucoma chattoni, and the peritrichOpisthonecta henneguyi. The affiliations of the oligohymenophoreans were assessed using both distance matrix (DM) and maximum parsimony (MP) analyses. Variations do exist in the phylogenies created by the two methods. However,

Spencer J. Greenwood; Mitchell L. Sogin; Denis H. Lynn

1991-01-01

203

Prolixibacter bellariivorans gen. nov., sp. nov., a sugar-fermenting, psychrotolerant anaerobe of the phylum Bacteroidetes, isolated from a marine-sediment fuel cell.  

PubMed

A Gram-negative, non-motile, filamentous, rod-shaped, non-spore-forming bacterium (strain F2(T)) was isolated from the surface of an electricity-harvesting electrode incubated in marine sediments. Strain F2(T) does not contain c-type cytochromes, flexirubin or carotenoids. It is a facultative anaerobe that can ferment sugars by using a mixed acid fermentation pathway and it can grow over a wide range of temperatures (4-42 degrees C). The DNA G+C (44.9 mol%) content and chemotaxonomic characteristics (major fatty acids, a-15 : 0 and 15 : 0) were consistent with those of species within the phylum Bacteroidetes. Phylogenetic analysis of the 16S rRNA nucleotide and elongation factor G amino acid sequences indicated that strain F2(T) represents a unique phylogenetic cluster within the phylum Bacteroidetes. On the basis of 16S rRNA gene sequence phylogeny, the closest relative available in pure culture, Alkaliflexus imshenetskii, is only 87.5 % similar to strain F2(T). Results from physiological, biochemical and phylogenetic analyses showed that strain F2(T) should be classified as a novel genus and species within the phylum Bacteroidetes, for which the name Prolixibacter bellariivorans gen. nov., sp. nov. is proposed. The type strain is F2(T) (=ATCC BAA-1284(T)=JCM 13498(T)). PMID:17392190

Holmes, Dawn E; Nevin, Kelly P; Woodard, Trevor L; Peacock, Aaron D; Lovley, Derek R

2007-04-01

204

Supplemental Online Materials Cytoskeletal Organization  

E-print Network

bar = 5 microns. #12;Supplemental Online Materials 3 Cryptosporidium Movies depicting gliding motilitySupplemental Online Materials 1 Cytoskeletal Organization The phylum Apicomplexa (1, 2) is defined C Figure 1 #12;Supplemental Online Materials 2 Gliding Motility Apicomplexan parasites display

Sibley, David

205

ENTERIC COCCIDIOSIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Coccidia are obligate intracellular parasites normally found in the intestinal tract. They belong to phylum Apicomplexa, class Sporozoasida, order Eucoccidiorida, and, depending on the species, family Eimeriidae, Cryptosporidiidae, or Sarcocystidae. Coccidian genera that infect cats and dogs are Iso...

206

Colpodella spp.–like Parasite Infection in Woman, China  

PubMed Central

The phylum Apicomplexa comprises intracellular protozoa that include many human pathogens. Their nearest relatives are chromerids and colpodellids. We report a case of a Babesia spp.–like relapsing infection caused by a newly described microorganism related to the Apicomplexa. This case is highly suggestive of a previously undescribed type of colpodellid that infects vertebrates. PMID:22260904

Yuan, Cong L.; Keeling, Patrick J.; Krause, Peter J.; Horak, Ales; Bent, Stephen; Rollend, Lindsay

2012-01-01

207

Elongation Factor-1a is a novel protein associated with host cell invasion and a potential protective antigen of Cryptosporidium parvum*  

Technology Transfer Automated Retrieval System (TEKTRAN)

The phylum Apicomplexa comprises obligate intracellular parasites that infect vertebrates. All invasive forms of Apicomplexa possess a unique complex of organelles at the anterior end, referred to as the apical complex, which is involved in host cell invasion. Previously, we generated the chicken m...

208

Improvement on the visualization of cytoskeletal structures of protozoan parasites using high-resolution field emission scanning electron microscopy (FESEM).  

PubMed

The association of high resolution field emission scanning electron microscopy (FESEM), with a more efficient system of secondary electron (SE) collection and in-lens specimen position, provided a great improvement in the specimen's topographical contrast and in the generation of high-resolution images. In addition, images obtained with the use of the high-resolution backscattered electrons (BSE) detector provided a powerful tool for immunocytochemical analysis of biological material. In this work, we show the contribution of the FESEM to the detailed description of cytoskeletal structures of the protozoan parasites Herpetomonas megaseliae, Trypanosoma brucei and Giardia lamblia. High-resolution images of detergent extracted H. megaseliae and T. brucei showed the profile of the cortical microtubules, also known as sub-pellicular microtubules (SPMT), and protein bridges cross-linking them. Also, it was possible to visualize fine details of the filaments that form the lattice-like structure of the paraflagellar rod (PFR) and its connection with the axoneme. In G. lamblia, it was possible to observe the intricate structure of the adhesive disk, funis (a microtubular array) and other cytoskeletal structures poorly described previously. Since most of the stable cytoskeletal structures of this protozoan rely on tubulin, we used the BSE images to accurately map immunolabeled tubulin in its cytoskeleton. Our results suggest that the observation of detergent extracted parasites using FESEM associated to backscattered analysis of immunolabeled specimens represents a new approach for the study of parasite cytoskeletal elements and their protein associations. PMID:15995880

Sant'Anna, Celso; Campanati, Loraine; Gadelha, Catarina; Lourenço, Daniela; Labati-Terra, Letícia; Bittencourt-Silvestre, Joana; Benchimol, Marlene; Cunha-e-Silva, Narcisa Leal; De Souza, Wanderley

2005-07-01

209

Clathrin-dependent pathways and the cytoskeleton network are involved in ceramide endocytosis by a parasitic protozoan, Giardia lamblia  

PubMed Central

Although identified as an early-diverged protozoan, Giardia lamblia shares many similarities with higher eukaryotic cells, including an internal membrane system and cytoskeleton, as well as secretory pathways. However, unlike many other eukaryotes, Giardia does not synthesize lipids de novo, but rather depends on exogenous sources for both energy production and organelle or membrane biogenesis. It is not known how lipid molecules are taken up by this parasite and if endocytic pathways are involved in this process. In this investigation, we tested the hypothesis that highly regulated and selective lipid transport machinery is present in Giardia and necessary for the efficient internalization and intracellular targeting of ceramide molecules, the major sphingolipid precursor. Using metabolic and pathway inhibitors, we demonstrate that ceramide is internalized through endocytic pathways and is primarily targeted into perinuclear/endoplasmic reticulum membranes. Further investigations suggested that Giardia uses both clathrin-dependent pathways and the actin cytoskeleton for ceramide uptake, as well as microtubule filaments for intracellular localization and targeting. We speculate that this parasitic protozoan has evolved cytoskeletal and clathrin-dependent endocytic mechanisms for importing ceramide molecules from the cell exterior for the synthesis of membranes and vesicles during growth and differentiation. PMID:17087963

Hernandez, Yunuen; Castillo, Cynthia; Roychowdhury, Sukla; Hehl, Adrian; Aley, Stephen B.; Das, Siddhartha

2007-01-01

210

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 PMID:6592587

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

1984-01-01

211

Protozoan infections (Toxoplasma gondii, Neospora caninum and Sarcocystis spp.) in sheep and goats: recent advances.  

PubMed

The protozoan parasite Toxoplasma gondii is a serious cause of fetal mortality in sheep and goats. Oocysts, the parasite stage responsible for initiating infection, are produced following a primary infection in cats. A primary infection in pregnant sheep and goats can establish a placental and fetal infection which may result in fetal death and resorption, abortion or stillbirth. Diagnosis is aided by the clinical picture, the presence of characteristic small white necrotic foci in placental cotyledons, the possible presence of a mummified fetus and on fetal serology and histopathology. Development of the polymerase chain reaction (PCR) specific for T. gondii may also provide a valuable diagnostic tool. Measures to control abortion include improved management of farm cats, fodder and water. Vaccination of sheep with the live vaccine is an effective preventive measure and the use of decoquinate in feed may be useful in some situations. Neospora caninum is related to T. gondii and while its asexual life cycle is similar to that of the latter it is currently not known whether it has a similar sexual life cycle in a definitive host. Neospora is an important cause of fetal loss in cattle and parallels that of T. gondii infection in sheep and goats. While it does not appear to cause frequent losses in these latter animals, experimental infection is readily induced in them and if initiated during pregnancy provides a very good model of the bovine infection. Furthermore clinical signs and pathological lesions in sheep and goats are similar to those induced in them by T. gondii, although there are subtle histopathological differences. These changes will aid possible diagnosis as will specific serological tests such as the indirect immunofluorescent antibody test and the enzyme linked immunosorbent assay and the PCR. Sarcocystis, which exists as numerous species, undergoes a coccidian-like life cycle with each having a distinctive definitive (usually carnivore) host which excretes sporocysts into the environment. Clinical sarcocystiosis is much less commonly diagnosed than toxoplasmosis and neither is it normally associated with fetal infection or abortion in either sheep or goats. However, infection is extremely common throughout the world and follows ingestion of food or water contaminated with sporocysts. Clinical signs, when seen, include fever, anaemia, inappetance and weight loss or reduced weight gain. Central nervous signs (hind limb weakness, ataxia, paresis), acute myopathy and death may occur. Diagnosis is difficult as infection is so common and clinical signs absent, mild or non-specific. Serology may be useful in some situations and histopathology/immunohistochemistry is valuable for confirming the cause of death. Control relies on preventing contamination of pasture and water with faeces of dogs, foxes and cats or by controlling access of young susceptible stock to contaminated land. Relatively little is known of the immunity induced by infection with Sarcocystis spp. but research indicates that protective immunity does develop and that cell-mediated mechanisms are probably important. It is likely that sarcocystiosis is underdiagnosed as a problem and that better diagnostic methods are needed to show the true extent of the losses caused. Neosporosis on the other hand would appear not to be so common in sheep and goats. The value of experimental infections in these animals may be to provide a comparative model of the infection in cattle in the same way that our understanding of toxoplasmosis in sheep provides a superior model of human toxoplasmosis. PMID:9689743

Buxton, D

1998-01-01

212

Exploring the potential of small RNA subunit and ITS sequences for resolving phylogenetic relationships within the phylum Ctenophora.  

PubMed

Ctenophores are a phylum of non-bilaterian marine (mostly planktonic) animals, characterised by several unique synapomorphies (e.g., comb rows, apical organ). Relationships between and within the nine recognised ctenophore orders are far from understood, notably due to a paucity of phylogenetically informative anatomical characters. Previous attempts to address ctenophore phylogeny using molecular data (18S rRNA) led to poorly resolved trees but demonstrated the paraphyly of the order Cydippida. Here we compiled an updated 18S rRNA data set, notably including a few newly sequenced species representing previously unsampled families (Lampeidae, Euryhamphaeidae), and we constructed an additional more rapidly evolving ITS1 + 5.8S rRNA + ITS2 alignment. These data sets were analysed separately and in combination under a probabilistic framework, using different methods (maximum likelihood, Bayesian inference) and models (e.g., doublet model to accommodate secondary structure; data partitioning). An important lesson from our exploration of these datasets is that the fast-evolving internal transcribed spacer (ITS) regions are useful markers for reconstructing high-level relationships within ctenophores. Our results confirm the paraphyly of the order Cydippida (and thus a "cydippid-like" ctenophore common ancestor) and suggest that the family Mertensiidae could be the sister group of all other ctenophores. The family Lampeidae (also part of the former "Cydippida") is probably the sister group of the order Platyctenida (benthic ctenophores). The order Beroida might not be monophyletic, due to the position of Beroe abyssicola outside of a clade grouping the other Beroe species and members of the "Cydippida" family Haeckeliidae. Many relationships (e.g. between Pleurobrachiidae, Beroida, Cestida, Lobata, Thalassocalycida) remain unresolved. Future progress in understanding ctenophore phylogeny will come from the use of additional rapidly evolving markers and improvement of taxonomic sampling. PMID:25440713

Simion, Paul; Bekkouche, Nicolas; Jager, Muriel; Quéinnec, Eric; Manuel, Michaël

2014-09-01

213

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. PMID:25183067

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

2014-01-01

214

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae) from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) of Round Island, Mauritius: an endangered parasite?  

PubMed

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae), C. durelli n. sp., is described from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) from Round Island, Mauritius. Six of 11 hosts were infected. Oöcysts are spherical to subspherical, 19.2 × 18.2 (17.5-21 × 16-21) ?m, n = 20, and have a shape index (mean length/mean width) of 1.05 (1.02-1.09). The bi-layered wall is composed of an outer layer of c.0.6 ?m thick and an inner layer of c.0.4 ?m thick. A micropyle, oöcyst residuum and polar granule are absent. Sporocysts are ellipsoidal, 14.7 × 11.0 (13-16 × 9.5-11.5) ?m, n = 20, and have a shape index of 1.33. Both Stieda and substieda bodies are present. The sporocyst residuum measures c.12 × 4.5 ?m, is surrounded by sporozoites and composed of numerous granules. Refractile bodies are present but not clearly visible. This is the first coccidian parasite reported from the family Bolyeridae and the first species of Caryospora durrelli [corrected] reported from the Mascarenes. Conservation issues concerning parasites of endangered host species are discussed. PMID:21279561

Daszak, Peter; Ball, Stanley J; Streicker, Daniel G; Jones, Carl G; Snow, Keith R

2011-02-01

215

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

216

Control of malaria and other vector-borne protozoan diseases in the tropics: enduring challenges despite considerable progress and achievements  

PubMed Central

Vector-borne protozoan diseases represent a serious public health challenge, especially in the tropics where poverty together with vector-favorable climates are the aggravating factors. Each of the various strategies currently employed to face these scourges is seriously inadequate. Despite enormous efforts, vaccines—which represent the ideal weapon against these parasitic diseases—are yet to be sufficiently developed and implemented. Chemotherapy and vector control are therefore the sole effective attempts to minimize the disease burden. Nowadays, both strategies are also highly challenged by the phenomenon of drug and insecticide resistance, which affects virtually all interventions currently used. The recently growing support from international organizations and governments of some endemic countries is warmly welcome, and should be optimally exploited in the various approaches to drug and insecticide research and development to overcome the burden of these prevalent diseases, especially malaria, leishmaniasis, Human African Trypanosomiasis (HAT), and Chagas disease. PMID:24401663

2014-01-01

217

Studies on synergistic toxic effects of copper and dithiocarbamate pesticides with the ciliate protozoan Colpidium campylum (Stokes).  

PubMed

The toxicity of seven dithiocarbamates and interactions occurring with copper were studied with the ciliate protozoan Colpidium campylum. No product was toxic at 0.1 mg liter-1. Thiram and mancozeb are the most toxic products (lethal at 1 mg liter-1) and ziram and propineb the least toxic. Concerning interactions with copper, no or slight interactions were observed with propineb and mancozeb, although a strong synergistic toxic effect was observed in a previous work with two structurally related products, maneb and zineb. On the contrary, the responses observed with alkyl-related dithiocarbamates (ferbam and ziram) and ethylene bis-related dithiocarbamates (nabam, thiram, and metiram) are in correlation with the results known in the literature. The synergistic toxic effect of copper and dithiocarbamates thus seems to be related mainly to the alkyl- or the ethylene bis-dithiocarbamate structure, but is not constant for molecules associated with metals (propineb, mancozeb, maneb, and zineb). PMID:2114279

Bonnemain, H; Dive, D

1990-06-01

218

Control of malaria and other vector-borne protozoan diseases in the tropics: enduring challenges despite considerable progress and achievements.  

PubMed

Vector-borne protozoan diseases represent a serious public health challenge, especially in the tropics where poverty together with vector-favorable climates are the aggravating factors. Each of the various strategies currently employed to face these scourges is seriously inadequate. Despite enormous efforts, vaccines-which represent the ideal weapon against these parasitic diseases-are yet to be sufficiently developed and implemented. Chemotherapy and vector control are therefore the sole effective attempts to minimize the disease burden. Nowadays, both strategies are also highly challenged by the phenomenon of drug and insecticide resistance, which affects virtually all interventions currently used. The recently growing support from international organizations and governments of some endemic countries is warmly welcome, and should be optimally exploited in the various approaches to drug and insecticide research and development to overcome the burden of these prevalent diseases, especially malaria, leishmaniasis, Human African Trypanosomiasis (HAT), and Chagas disease. PMID:24401663

Zofou, Denis; Nyasa, Raymond B; Nsagha, Dickson S; Ntie-Kang, Fidele; Meriki, Henry D; Assob, Jules Clement N; Kuete, Victor

2014-01-01

219

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

220

Detection of Infectious Cryptosporidium in Drinking Water Waterborne transmission of the protozoan parasite Cryptosporidium remains a significant threat of disease with severe consequences  

E-print Network

Detection of Infectious Cryptosporidium in Drinking Water Waterborne transmission of the protozoan parasite Cryptosporidium remains a significant threat of disease with severe consequences for persons.S. for the presence of infectious Cryptospo- ridium using a cell culture-polymerase chain reaction (CC-PCR) technique

221

Expression profiling using random genomic DNA microarrays identifies differentially expressed genes associated with three major developmental stages of the protozoan parasite Leishmania major  

Microsoft Academic Search

To complete its life cycle, protozoan parasites of the genus Leishmaniaundergo at least three major developmental transitions. However, previous efforts to identify genes showing stage regulated changes in transcript abundance have yielded relatively few. Here we used expression profiling to assess changes in transcript abundance in three stages: replicating promastigotes and infective non-replicating metacyclics, which occur in the sand fly

Natalia S. Akopyants; Robin S. Matlib; Elena N. Bukanova; Matthew R. Smedsa; Bernard H. Brownstein; Gary D. Stormo; Stephen M. Beverley

2004-01-01

222

Protozoan Grazing and Bacterial Production in Stratified Lake Vechten Estimated with Fluorescently Labeled Bacteria and by Thymidine Incorporation  

PubMed Central

In stratified Lake Vechten, The Netherlands, protozoan grazing was estimated on the basis of uptake of fluorescently labeled bacteria and compared with bacterial production estimated on the basis of thymidine incorporation. By using a grazer-free mixed bacterial population from the lake in continuous culture, an empirical relationship between cell production and thymidine incorporation was established. Thymidine incorporation into total cold-trichloroacetic-acid-insoluble macromolecules yielded a relatively constant empirical conversion factor of ca. 1018 (range, 0.38 × 1018 to 1.42 × 1018) bacteria mol of thymidine?1 at specific growth rates (?) ranging from 0.007 to 0.116 h?1. Although thymidine incorporation has been assumed to measure DNA synthesis thymidine incorporation appeared to underestimate the independently measured bacterial DNA synthesis by at least 1.5- to 13-fold, even if all incorporated label was assumed to be in DNA. However, incorporation into DNA was found to be insignificant as measured by conventional acid-base hydrolysis. Methodological problems of the thymidine technique are discussed. Like the cultures, Lake Vechten bacteria showed considerable thymidine incorporation into total macromolecules, but no significant incorporation into DNA was found by acid-base hydrolysis. This applied not only to the low-oxygen hypo- and metalimnion but also to the aerobic epilimnion. Thus, the established empirical conversion factor for thymidine incorporation into total macromolecules was used to estimate bacterial production. Maximum production rates (141 × 106 bacteria liter?1 h?1; ?, 0.012 h?1) were found in the metalimnion and were 1 order of magnitude higher than in the epi- and hypolimnion. In all three strata, the estimated bacterial production was roughly balanced by the estimated protozoan grazing. Heterotrophic nanoflagellates were the major consumers of the bacterial production and showed maximum numbers (up to 40 × 106 heterotrophic nanoflagellates liter?1) in the microaerobic metalimnion. PMID:16347972

Bloem, Jaap; Ellenbroek, Frank M.; Bär-Gilissen, Marie-José B.; Cappenberg, Thomas E.

1989-01-01

223

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. PMID:23071396

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

2012-01-01

224

Development of Single-Nucleotide Polymorphism- Based Phylum-Specific PCR Amplification Technique: Application to the Community Analysis Using Ciliates as a Reference Organism  

PubMed Central

Despite recent advance in mass sequencing technologies such as pyrosequencing, assessment of culture-independent microbial eukaryote community structures using universal primers remains very difficult due to the tremendous richness and complexity of organisms in these communities. Use of a specific PCR marker targeting a particular group would provide enhanced sensitivity and more in-depth evaluation of microbial eukaryote communities compared to what can be achieved with universal primers. We discovered that many phylum- or group-specific single-nucleotide polymorphisms (SNPs) exist in small subunit ribosomal RNA (SSU rRNA) genes from diverse eukaryote groups. By applying this discovery to a known simple allele-discriminating (SAP) PCR method, we developed a technique that enables the identification of organisms belonging to a specific higher taxonomic group (or phylum) among diverse types of eukaryotes. We performed an assay using two complementary methods, pyrosequencing and clone library screening. In doing this, specificities for the group (ciliates) targeted in this study in bulked environmental samples were 94.6% for the clone library and 99.2% for pyrosequencing, respectively. In particular, our novel technique showed high selectivity for rare species, a feature that may be more important than the ability to identify quantitatively predominant species in community structure analyses. Additionally, our data revealed that a target-specific library (or ciliate-specific one for the present study) can better explain the ecological features of a sampling locality than a universal library. PMID:22965748

Jung, Jae-Ho; Kim, Sanghee; Ryu, Seongho; Kim, Min-Seok; Baek, Ye-Seul; Kim, Se-Joo; Choi, Joong- Ki; Park, Joong-Ki; Min, Gi-Sik

2012-01-01

225

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

226

The candidate phylum Poribacteria by single-cell genomics: new insights into phylogeny, cell-compartmentation, eukaryote-like repeat proteins, and other genomic features.  

PubMed

The candidate phylum Poribacteria is one of the most dominant and widespread members of the microbial communities residing within marine sponges. Cell compartmentalization had been postulated along with their discovery about a decade ago and their phylogenetic association to the Planctomycetes, Verrucomicrobia, Chlamydiae superphylum was proposed soon thereafter. In the present study we revised these features based on genomic data obtained from six poribacterial single cells. We propose that Poribacteria form a distinct monophyletic phylum contiguous to the PVC superphylum together with other candidate phyla. Our genomic analyses supported the possibility of cell compartmentalization in form of bacterial microcompartments. Further analyses of eukaryote-like protein domains stressed the importance of such proteins with features including tetratricopeptide repeats, leucin rich repeats as well as low density lipoproteins receptor repeats, the latter of which are reported here for the first time from a sponge symbiont. Finally, examining the most abundant protein domain family on poribacterial genomes revealed diverse phyH family proteins, some of which may be related to dissolved organic posphorus uptake. PMID:24498082

Kamke, Janine; Rinke, Christian; Schwientek, Patrick; Mavromatis, Kostas; Ivanova, Natalia; Sczyrba, Alexander; Woyke, Tanja; Hentschel, Ute

2014-01-01

227

Molecular assessment of hepatozoon (Apicomplexa: adeleorina) infections in wild canids and rodents from north Africa, with implications for transmission dynamics across taxonomic groups.  

PubMed

Parasites play a major role in ecosystems, and understanding of host-parasite interactions is important for predicting parasite transmission dynamics and epidemiology. However, there is still a lack of knowledge about the distribution, diversity, and impact of parasites in wildlife, especially from remote areas. Hepatozoon is a genus of apicomplexan parasites that is transmitted by ingestion of infected arthropod vectors. However, alternative modes of transmission have been identified such as trophic transmission. Using the 18S rRNA gene as a marker, we provide an assessment of Hepatozoon prevalence in six wild canid and two rodent species collected between 2003 and 2012 from remote areas in North Africa. By combining this with other predator-prey systems in a phylogenetic framework, we investigate Hepatozoon transmission dynamics in distinct host taxa. Prevalence was high overall among host species (African jerboa Jaculus jaculus [17/47, 36%], greater Egyptian jerboa Jaculus orientalis [5/7, 71%], side-striped jackal Canis adustus [1/2, 50%], golden jackal Canis aureus [6/32, 18%], pale fox Vulpes pallida [14/28, 50%], Rüppell's fox Vulpes rueppellii [6/11, 55%], red fox Vulpes vulpes [8/16, 50%], and fennec fox Vulpes zerda [7/11, 42%]). Phylogenetic analysis showed further evidence of occasional transmission of Hepatozoon lineages from prey to canid predators, which seems to occur less frequently than in other predator-prey systems such as between snakes and lizards. Due to the complex nature of the Hepatozoon lifecycle (heteroxenous and vector-borne), future studies on these wild host species need to clarify the dynamics of alternative modes of Hepatozoon transmission and identify reservoir and definitive hosts in natural populations. We also detected putative Babesia spp. (Apicomplexa: Piroplasmida) infections in two canid species from this region, V. pallida (1/28) and V. zerda (1/11). PMID:25050803

Maia, João P; Alvares, Francisco; Boraty?ski, Zbyszek; Brito, José C; Leite, João V; Harris, D James

2014-10-01

228

Species of coccidia (Apicomplexa: Eimeriidae) in shrews from Alaska, U.S.A., and northeastern Siberia, Russia, with description of two new species.  

PubMed

Fecal samples (n = 636) from 10 species of shrews collected in Alaska (n = 540) and northeastern Siberia (n = 96) were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Five distinct oocyst morphotypes were observed. Three types were consistent with oocysts of previously recognized coccidia species from other shrew hosts. These were Eimeria inyoni, E. vagrantis, and Isospora brevicauda, originally described from the inyo shrew (Sorex tenellus), dusky shrew (S. monticolus), and northern short-tailed shrew (Blarina brevicauda), respectively. We found 5 new host records for E. inyoni, 3 for E. vagrantis, and 3 for I. brevicauda. The 2 additional oocyst morphotypes, both from the tundra shrew (Sorex tundrensis), are putative new species. Sporulated oocysts of Eimeria beringiacea n. sp. are subspheroidal, 17.7 x 15.6 microm (14-24 x 13-20 microm) with a length (L)/width (W) ratio of 1.1 (1.0-1.4); these lack a micropyle (M), an oocyst residuum (OR), and a polar granule (PG). Sporocysts are ellipsoidal, 10.3 x 6.1 microm (7-14 x 4-8 microm), with a L/W ratio of 1.7 (1.3-2.3) and have a Stieda body (SB), Substieda body (SSB), and sporocyst residuum (SR). Oocysts of Eimeria tundraensis n. sp. are spheroidal to subspheroidal, 24.8 x 23.5 microm (23-26 x 22-25 microm), with a L/W ratio of 1.1 (1.0-1.2); these lack a M and OR, but a single PG is present. Sporocysts are elongate ellipsoidal, 15.4 x 8.3 microm (13-17 x 7-9 microm), with a L/W ratio of 1.9 (1.4-2.1) and have a SB, SSB, and SR. PMID:18576829

Lynch, A J; Duszynski, D W

2008-08-01

229

Toxoplasma gondii Actin Depolymerizing Factor Acts Primarily to Sequester G-actin*  

PubMed Central

Toxoplasma gondii is a protozoan parasite belonging to the phylum Apicomplexa. Parasites in this phylum utilize a unique process of motility termed gliding, which is dependent on parasite actin filaments. Surprisingly, 98% of parasite actin is maintained as G-actin, suggesting that filaments are rapidly assembled and turned over. Little is known about the regulated disassembly of filaments in the Apicomplexa. In higher eukaryotes, the related actin depolymerizing factor (ADF) and cofilin proteins are essential regulators of actin filament turnover. ADF is one of the few actin-binding proteins conserved in apicomplexan parasites. In this study we examined the mechanism by which T. gondii ADF (TgADF) regulates actin filament turnover. Unlike other members of the ADF/cofilin (AC) family, apicomplexan ADFs lack key F-actin binding sites. Surprisingly, this promotes their enhanced disassembly of actin filaments. Restoration of the C-terminal F-actin binding site to TgADF stabilized its interaction with filaments but reduced its net filament disassembly activity. Analysis of severing activity revealed that TgADF is a weak severing protein, requiring much higher concentrations than typical AC proteins. Investigation of TgADF interaction with T. gondii actin (TgACT) revealed that TgADF disassembled short TgACT oligomers. Kinetic and steady-state polymerization assays demonstrated that TgADF has strong monomer-sequestering activity, inhibiting TgACT polymerization at very low concentrations. Collectively these data indicate that TgADF promoted the efficient turnover of actin filaments via weak severing of filaments and strong sequestering of monomers. This suggests a dual role for TgADF in maintaining high G-actin concentrations and effecting rapid filament turnover. PMID:20042603

Mehta, Simren; Sibley, L. David

2010-01-01

230

2-acylamino-5-nitro-1,3-thiazoles: preparation and in vitro bioevaluation against four neglected protozoan parasites.  

PubMed

The 2-acylamino-5-nitro-1,3-thiazole derivatives (1-14) were prepared using a one step reaction. All compounds were tested in vitro against four neglected protozoan parasites (Giardia intestinalis, Trichomonas vaginalis, Leishmania amazonensis and Trypanosoma cruzi). Acetamide (9), valeroylamide (10), benzamide (12), methylcarbamate (13) and ethyloxamate (14) derivatives were the most active compounds against G. intestinalis and T. vaginalis, showing nanomolar inhibition. Compound 13 (IC50=10nM), was 536-times more active than metronidazole, and 121-fold more effective than nitazoxanide against G. intestinalis. Compound 14 was 29-times more active than metronidazole and 6.5-fold more potent than nitazoxanide against T. vaginalis. Ureic derivatives 2, 3 and 5 showed moderate activity against L. amazonensis. None of them were active against T. cruzi. Ligand efficiency indexes analysis revealed higher intrinsic quality of the most active 2-acylamino derivatives than nitazoxanide and metronidazole. In silico toxicity profile was also computed for the most active compounds. A very low in vitro mammalian cytotoxicity was obtained for 13 and 14, showing selectivity indexes (SI) of 246,300 and 141,500, respectively. Nitazoxanide showed an excellent leishmanicidal and trypanocidal effect, repurposing this drug as potential new antikinetoplastid parasite compound. PMID:24529307

Nava-Zuazo, Carlos; Chávez-Silva, Fabiola; Moo-Puc, Rosa; Chan-Bacab, Manuel Jesús; Ortega-Morales, Benjamín Otto; Moreno-Díaz, Hermenegilda; Díaz-Coutiño, Daniel; Hernández-Núñez, Emanuel; Navarrete-Vázquez, Gabriel

2014-03-01

231

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 PMID:24913268

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

232

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

PubMed

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. PMID:24948925

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

2014-01-01

233

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. PMID:24948925

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

2014-01-01

234

Association of RNA Polymerase Complexes of the Parasitic Protozoan Cryptosporidium parvum with Virus-Like Particles: Heterogeneous System†  

PubMed Central

RNA polymerase complexes were purified from Cryptosporidium parvum, a parasitic protozoan known to infect many species of mammals including humans. Western blot analysis revealed the association of the complexes with two different proteins, encoded by large and small segments of viral double-stranded RNAs. Each complex was found to contain only double-stranded RNA, both double- and single-stranded RNA, or only single-stranded RNA. Maximum RNA-dependent RNA polymerase activity was observed within the complexes containing both double- and single-stranded RNAs. These complexes possessed both transcriptase and replicase polymerase activities. Virus-like particles with a diameter of 31 nm were copurified with RNA polymerase complexes, and buoyant density and polymerase studies suggest that C. parvum harbors a putative double-stranded RNA virus which separately encapsidates the large and small RNA segments. The mechanism of replication and other characteristics of this virus are similar to those of the viruses of the family Partitiviridae, previously identified only in fungi and plants. PMID:10846057

Khramtsov, Nikolai V.; Upton, Steve J.

2000-01-01

235

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.

Thomas, Frédéric; Lafferty, Kevin D.; Brodeur, Jacques; Elguero, Eric; Gauthier-Clerc, Michel; Missé, Dorothée

2012-01-01

236

Anion inhibition studies of the ?-carbonic anhydrase from the protozoan pathogen Trypanosoma cruzi, the causative agent of Chagas disease.  

PubMed

The protozoan pathogen Trypanosoma cruzi, the causative agent of Chagas disease, encodes an ?-class carbonic anhydrase (CA, EC 4.2.1.1), TcCA, which was recently shown to be crucial for its life cycle. Thiols, a class of strong TcCA inhibitors, were also shown to block the growth of the pathogen in vitro. Here we report the inhibition of TcCA by inorganic and complex anions and other molecules interacting with zinc proteins, such as sulfamide, sulfamic acid, phenylboronic/arsonic acids. TcCA was inhibited in the low micromolar range by iodide, cyanate, thiocyanate, hydrogensulfide and trithiocarbonate (KIs in the range of 44-93 ?M), but the best inhibitor was diethyldithiocarbamate (KI=5 ?M). Sulfamide showed an inhibition constant of 120 ?M, but sulfamic acid was much less effective (KI of 10.6 mM). The discovery of diethyldithiocarbamate as a low micromolar TcCA inhibitor may be useful to detect leads for developing anti-Trypanosoma agents with a diverse mechanism of action compared to clinically used drugs (benznidazole, nifurtimox) for which significant resistance emerged. PMID:23790722

Pan, Peiwen; Vermelho, Alane Beatriz; Scozzafava, Andrea; Parkkila, Seppo; Capasso, Clemente; Supuran, Claudiu T

2013-08-01

237

The effect of tunicamycin on the glucose uptake, growth, and cellular adhesion in the protozoan parasite Crithidia fasciculata.  

PubMed

Crithidia fasciculata represents a very interesting model organism to study biochemical, cellular, and genetic processes unique to members of the family of the Trypanosomatidae. Thus, C. fasciculata parasitizes several species of insects and has been widely used to test new therapeutic strategies against parasitic infections. By using tunicamycin, a potent inhibitor of glycosylation in asparaginyl residues of glycoproteins (N-glycosylation), we demonstrate that N-glycosylation in C. fasciculata cells is involved in modulating glucose uptake, dramatically impacting growth, and cell adhesion. C. fasciculata treated with tunicamycin was severely affected in their ability to replicate and to adhere to polystyrene substrates and losing their ability to aggregate into small and large groups. Moreover, under tunicamycin treatment, the parasites were considerably shorter and rounder and displayed alterations in cytoplasmic vesicles formation. Furthermore, glucose uptake was significantly impaired in a tunicamycin dose-dependent manner; however, no cytotoxic effect was observed. Interestingly, this effect was reversible. Thus, when tunicamycin was removed from the culture media, the parasites recovered its growth rate, cell adhesion properties, and glucose uptake. Collectively, these results suggest that changes in the tunicamycin-dependent glycosylation levels can influence glucose uptake, cell growth, and adhesion in the protozoan parasite C. fasciculata. PMID:24894907

Rojas, Robert; Segovia, Christopher; Trombert, Annette Nicole; Santander, Javier; Manque, Patricio

2014-10-01

238

Structure and seasonal dynamics of the protozoan community (heterotrophic flagellates, ciliates, amoeboid protozoa) in the plankton of a large river (River Danube, Hungary).  

PubMed

Seasonal dynamics of all major protozoan groups were investigated in the plankton of the River Danube, upstream of Budapest (Hungary), by bi-weekly sampling over a 1-year long period. Sixty-one heterotrophic flagellate, 14 naked amoeba, 50 testate amoeba, 4 heliozoan and 83 ciliate morphospecies were identified. The estimated abundance ranges of major groups throughout the year were as follows: heterotrophic flagellates, 0.27-7.8 x 10(6)ind.l(-1); naked amoebae, max. 3300ind.l(-1); testaceans, max. 1600ind.l(-1); heliozoans, max. 8500ind.l(-1); ciliates, 132-34,000ind.l(-1). In terms of biovolume, heterotrophic flagellates dominated throughout the year (max. 0.58mm(3)l(-1)), and ciliates only exceeded their biovolume in summer (max. 0.76mm(3)l(-1)). Naked amoeba and heliozoan biovolume was about one, and testacean biovolume 1-3, orders of magnitude lower than that of ciliates. In winter, flagellates, mainly chrysomonads, had the highest biomass, whilst ciliates were dominated by peritrichs. In 2005 from April to July a long spring/summer peak occurred for all protozoan groups. Beside chrysomonads typical flagellates were choanoflagellates, bicosoecids and abundant microflagellates (large chrysomonads and Collodictyon). Most abundant ciliates were oligotrichs, while Phascolodon, Urotricha, Vorticella, haptorids, Suctoria, Climacostomum and Stokesia also contributed significantly to biovolume during rapid succession processes. In October and November a second high protozoan peak occurred, with flagellate dominance, and slightly different taxonomic composition. PMID:19285382

Kiss, Aron Keve; Acs, Eva; Kiss, Keve Tihamér; Török, Júlia Katalin

2009-05-01

239

Rapid Escape of the dot/icm Mutants of Legionella pneumophila into the Cytosol of Mammalian and Protozoan Cells? †  

PubMed Central

The Legionella pneumophila-containing phagosome evades endocytic fusion and intercepts endoplasmic reticulum (ER)-to-Golgi vesicle traffic, which is believed to be mediated by the Dot/Icm type IV secretion system. Although phagosomes harboring dot/icm mutants are thought to mature through the endosomal-lysosomal pathway, colocalization studies with lysosomal markers have reported contradictory results. In addition, phagosomes harboring the dot/icm mutants do not interact with endocytosed materials, which is inconsistent with maturation of the phagosomes in the endosomal-lysosomal pathway. Using multiple strategies, we show that the dot/icm mutants defective in the Dot/Icm structural apparatus are unable to maintain the integrity of their phagosomes and escape into the cytoplasm within minutes of entry into various mammalian and protozoan cells in a process independent of the type II secretion system. In contrast, mutants defective in cytoplasmic chaperones of Dot/Icm effectors and rpoS, letA/S, and letE regulatory mutants are all localized within intact phagosomes. Importantly, non-dot/icm L. pneumophila mutants whose phagosomes acquire late endosomal-lysosomal markers are all located within intact phagosomes. Using high-resolution electron microscopy, we show that phagosomes harboring the dot/icm transporter mutants do not fuse to lysosomes but are free in the cytoplasm. Inhibition of ER-to-Golgi vesicle traffic by brefeldin A does not affect the integrity of the phagosomes harboring the parental strain of L. pneumophila. We conclude that the Dot/Icm transporter is involved in maintaining the integrity of the L. pneumophila phagosome, independent of interception of ER-to-Golgi vesicle traffic, which is a novel function of type IV secretion systems. PMID:17438033

Molmeret, Maëlle; Santic’, Marina; Asare, Rexford; Carabeo, Reynold A.; Kwaik, Yousef Abu

2007-01-01

240

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. PMID:22905196

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

2012-01-01

241

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

PubMed Central

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

2013-01-01

242

A Genomewide Overexpression Screen Identifies Genes Involved in the Phosphatidylinositol 3-Kinase Pathway in the Human Protozoan Parasite Entamoeba histolytica  

PubMed Central

Entamoeba histolytica is a protozoan parasite that causes amoebic dysentery and liver abscess. E. histolytica relies on motility, phagocytosis, host cell adhesion, and proteolysis of extracellular matrix for virulence. In eukaryotic cells, these processes are mediated in part by phosphatidylinositol 3-kinase (PI3K) signaling. Thus, PI3K may be critical for virulence. We utilized a functional genomics approach to identify genes whose products may operate in the PI3K pathway in E. histolytica. We treated a population of trophozoites that were overexpressing genes from a cDNA library with a near-lethal dose of the PI3K inhibitor wortmannin. This screen was based on the rationale that survivors would be overexpressing gene products that directly or indirectly function in the PI3K pathway. We sequenced the overexpressed genes in survivors and identified a cDNA encoding a Rap GTPase, a protein previously shown to participate in the PI3K pathway. This supports the validity of our approach. Genes encoding a coactosin-like protein, EhCoactosin, and a serine-rich E. histolytica protein (SREHP) were also identified. Cells overexpressing EhCoactosin or SREHP were also less sensitive to a second PI3K inhibitor, LY294002. This corroborates the link between these proteins and PI3K. Finally, a mutant cell line with an increased level of phosphatidylinositol (3,4,5)-triphosphate, the product of PI3K activity, exhibited increased expression of SREHP and EhCoactosin. This further supports the functional connection between these proteins and PI3K in E. histolytica. To our knowledge, this is the first forward-genetics screen adapted to reveal genes participating in a signal transduction pathway in this pathogen. PMID:24442890

Koushik, Amrita B.; Welter, Brenda H.; Rock, Michelle L.

2014-01-01

243

Evidence for the induction of casein kinase II in bovine lymphocytes transformed by the intracellular protozoan parasite Theileria parva.  

PubMed Central

Theileria parva is an obligate, intracellular, parasitic protozoan that causes East Coast fever, an acute leukemia-like disease of cattle. T. parva and the related parasite, Theileria annulata, are unique among protozoa in that their intralymphocytic stages induce transformation of bovid lymphocytes. Comparison of in vitro protein kinase activities between uninfected IL-2-dependent T lymphoblasts and T. parva-infected lymphocytes revealed a 4.7- to 12-fold increase in total phosphorylation and the induction of a group of Theileria infection-specific phosphoproteins. The enzyme that phosphorylates these substrates is a serine/threonine kinase with substrate and effector specificities of casein kinase (CK) II. Northern blot analyses revealed a 3.9- to 6.0-fold increase in CKII alpha mRNA in the infected cells relative to the controls. Furthermore, a marked increase of CKII antigen was observed on Western blots of materials prepared from the infected cell lines. The antibovine CKII antibody used in these studies immunoprecipitated a protein kinase that phosphorylated casein in a reaction that was inhibited by low (nM) quantities of heparin. Our data show marked increases of bovine CKII at the transcriptional, translational and functional levels in T. parva-infected lymphocytes, relative to quiescent cells or IL-2-dependent parental lymphoblasts. Bovine CKII thus appears to be constitutively activated in these cells and we propose that this kinase may be an important element in the signal-transducing pathways activated by Theileria in bovid lymphocytes and perhaps in some leukemic cells. Images PMID:8467809

ole-MoiYoi, O K; Brown, W C; Iams, K P; Nayar, A; Tsukamoto, T; Macklin, M D

1993-01-01

244

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. PMID:24533297

Shridhar, Surekha; Hassan, Kolaleh; Sullivan, David J.; Vasta, Gerardo R.; Fernández Robledo, José A.

2013-01-01

245

Assessing the resistance and bioremediation ability of selected bacterial and protozoan species to heavy metals in metal-rich industrial wastewater  

PubMed Central

Background Heavy-metals exert considerable stress on the environment worldwide. This study assessed the resistance to and bioremediation of heavy-metals by selected protozoan and bacterial species in highly polluted industrial-wastewater. Specific variables (i.e. chemical oxygen demand, pH, dissolved oxygen) and the growth/die-off-rates of test organisms were measured using standard methods. Heavy-metal removals were determined in biomass and supernatant by the Inductively Couple Plasma Optical Emission Spectrometer. A parallel experiment was performed with dead microbial cells to assess the biosorption ability of test isolates. Results The results revealed that the industrial-wastewater samples were highly polluted with heavy-metal concentrations exceeding by far the maximum limits (in mg/l) of 0.05-Co, 0.2-Ni, 0.1-Mn, 0.1-V, 0.01-Pb, 0.01-Cu, 0.1-Zn and 0.005-Cd, prescribed by the UN-FAO. Industrial-wastewater had no major effects on Pseudomonas putida, Bacillus licheniformis and Peranema sp. (growth rates up to 1.81, 1.45 and 1.43 d-1, respectively) compared to other test isolates. This was also revealed with significant COD increases (p?protozoan isolates (up to 24% increase). Living Pseudomonas putida demonstrated the highest removal rates of heavy metals (Co-71%, Ni-51%, Mn-45%, V-83%, Pb-96%, Ti-100% and Cu-49%) followed by Bacillus licheniformis (Al-23% and Zn-53%) and Peranema sp. (Cd-42%). None of the dead cells were able to remove more than 25% of the heavy metals. Bacterial isolates contained the genes copC, chrB, cnrA3 and nccA encoding the resistance to Cu, Cr, Co-Ni and Cd-Ni-Co, respectively. Protozoan isolates contained only the genes encoding Cu and Cr resistance (copC and chrB genes). Peranema sp. was the only protozoan isolate which had an additional resistant gene cnrA3 encoding Co-Ni resistance. Conclusion Significant differences (p?

2013-01-01

246

A Novel Soluble Immune-Type Receptor (SITR) in Teleost Fish: Carp SITR Is Involved in the Nitric Oxide-Mediated Response to a Protozoan Parasite  

PubMed Central

Background The innate immune system relies upon a wide range of germ-line encoded receptors including a large number of immunoglobulin superfamily (IgSF) receptors. Different Ig-like immune receptor families have been reported in mammals, birds, amphibians and fish. Most innate immune receptors of the IgSF are type I transmembrane proteins containing one or more extracellular Ig-like domains and their regulation of effector functions is mediated intracellularly by distinct stimulatory or inhibitory pathways. Methodology/Principal Findings Carp SITR was found in a substracted cDNA repertoire from carp macrophages, enriched for genes up-regulated in response to the protozoan parasite Trypanoplasma borreli. Carp SITR is a type I protein with two extracellular Ig domains in a unique organisation of a N-proximal V/C2 (or I-) type and a C-proximal V-type Ig domain, devoid of a transmembrane domain or any intracytoplasmic signalling motif. The carp SITR C-proximal V-type Ig domain, in particular, has a close sequence similarity and conserved structural characteristics to the mammalian CD300 molecules. By generating an anti-SITR antibody we could show that SITR protein expression was restricted to cells of the myeloid lineage. Carp SITR is abundantly expressed in macrophages and is secreted upon in vitro stimulation with the protozoan parasite T. borreli. Secretion of SITR protein during in vivo T. borreli infection suggests a role for this IgSF receptor in the host response to this protozoan parasite. Overexpression of carp SITR in mouse macrophages and knock-down of SITR protein expression in carp macrophages, using morpholino antisense technology, provided evidence for the involvement of carp SITR in the parasite-induced NO production. Conclusion/Significance We report the structural and functional characterization of a novel soluble immune-type receptor (SITR) in a teleost fish and propose a role for carp SITR in the NO-mediated response to a protozoan parasite. PMID:21305002

Ribeiro, Carla M. S.; Bird, Steve; Raes, Geert; Ghassabeh, Gholamreza H.; Schijns, Virgil E. J. C.; Pontes, Maria J. S. L.; Savelkoul, Huub F. J.; Wiegertjes, Geert F.

2011-01-01

247

Reactive nitrogen and oxygen species, and iron sequestration contribute to macrophage-mediated control of Encephalitozoon cuniculi (Phylum Microsporidia) infection in vitro and in vivo.  

PubMed

Encephalitozoon cuniculi (Phylum Microsporidia) infects a wide range of mammals, and replicates within resting macrophages. Activated macrophages, conversely, inhibit replication and destroy intracellular organisms. These studies were performed to assess mechanisms of innate immune responses expressed by macrophages to control E. cuniculi infection. Addition of reactive oxygen and nitrogen species inhibitors to activated murine peritoneal macrophages statistically significantly, rescued E. cuniculi infection ex vivo. Mice deficient in reactive oxygen species, reactive nitrogen species, or both survived ip inoculation of E. cuniculi, but carried significantly higher peritoneal parasite burdens than wild-type mice at 1 and 2 weeks post inoculation. Infected peritoneal macrophages could still be identified 4 weeks post inoculation in mice deficient in reactive nitrogen species. L-tryptophan supplementation of activated murine peritoneal macrophage cultures ex vivo failed to rescue microsporidia infection. Addition of ferric citrate to supplement iron, however, did significantly rescue E. cuniculi infection in activated macrophages and further increased parasite replication in non-activated macrophages over non-treated resting control macrophages. These results demonstrate the contribution of reactive oxygen and nitrogen species, as well as iron sequestration, to innate immune responses expressed by macrophages to control E. cuniculi infection. PMID:20888426

Didier, Elizabeth S; Bowers, Lisa C; Martin, Aaron D; Kuroda, Marcelo J; Khan, Imtiaz A; Didier, Peter J

2010-12-01

248

Reactive nitrogen and oxygen species, and iron sequestration contribute to macrophage-mediated control of Encephalitozoon cuniculi (Phylum Microsporidia) infection in vitro and in vivo  

PubMed Central

Encephalitozoon cuniculi (Phylum Microsporidia) infects a wide range of mammals, and replicates within resting macrophages. Activated macrophages, conversely, inhibit replication and destroy intracellular organisms. These studies were performed to assess mechanisms of innate immune responses expressed by macrophages to control E. cuniculi infection. Addition of reactive oxygen and nitrogen species inhibitors to activated murine peritoneal macrophages statistically significantly, rescued E. cuniculi infection ex vivo. Mice deficient in reactive oxygen species, reactive nitrogen species, or both survived ip inoculation of E. cuniculi, but carried significantly higher peritoneal parasite burdens than wild-type mice at 1 and 2 weeks post inoculation. Infected peritoneal macrophages could still be identified 4 weeks post inoculation in mice deficient in reactive nitrogen species. L-tryptophan supplementation of activated murine peritoneal macrophage cultures ex vivo failed to rescue microsporidia infection. Addition of ferric citrate to supplement iron, however, did significantly rescue E. cuniculi infection in activated macrophages and further increased parasite replication in non-activated macrophages over non-treated resting control macrophages. These results demonstrate the contribution of reactive oxygen and nitrogen species, as well as iron sequestration, to innate immune responses expressed by macrophages to control E. cuniculi infection. PMID:20888426

Didier, Elizabeth S.; Bowers, Lisa C.; Martin, Aaron D.; Kuroda, Marcelo J.; Khan, Imtiaz A.; Didier, Peter J.

2010-01-01

249

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

250

What factors drive seasonal variation of phytoplankton, protozoans and metazoans on leaves of Posidonia oceanica and in the water column along the coast of the Kerkennah Islands, Tunisia?  

PubMed

A hierarchical sampling design was used during two seasons (spring (May) and summer (August) 2006). Using this design, three regions of the Kerkennah Islands (Tunisia) were analyzed for the distribution of microalgal, protozoan and metazoan assemblages in two different habitats: (1) the water column; and (2) on Posidonia oceanica (L.) Delile (P. oceanica) leaves in shallow meadows. A total of 85 species were obtained. In particular, the diatom family Naviculacea consistently dominated (both numerically and in their diversity) the micro-algae in all regions for the two seasons of the study and in both habitats. In the Chergui region, which is the closest area to a source of impact, fast growing centric diatoms (such as Thalassionema, Rhizosolenia, Striatella, and Skeletonema) were identified as indicators of high organic matter and nutrient enrichment in water bodies. Protozoan and metazoan species abundance in the different regions indicate a non-random spatial and temporal distribution of the epiphytic organisms on leaves of P. oceanica that correlated with phytoplankton. The results also indicate that (1) the abundance of micro- and macroorganisms in the three regions were higher on P. oceanica leaves than in the water column for the two seasons; (2) environmental factors such as currents and tide influenced assemblages; and (3) the highest abundance was due to direct exposure to the polluted coast of Sfax and the effect of tidal asymmetries generating nutrient-rich inputs from the city. PMID:23498657

Mounir, Ben Brahim; Asma, Hamza; Sana, Ben Ismail; Lotfi, Mabrouk; Abderrahmen, Bouain; Lotfi, Aleya

2013-06-15

251

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-5T, 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-5T 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-5T (=JCM 17479T=CGMCC 1.5168T). PMID:24535138

Qiu, Yan-Ling; Kuang, Xiao-zhu; Shi, Xiao-shuang; Yuan, Xian-zheng; Guo, Rong-bo

2014-05-01

252

Oligosphaera ethanolica gen. nov., sp. nov., an anaerobic, carbohydrate-fermenting bacterium isolated from methanogenic sludge, and description of Oligosphaeria classis nov. in the phylum Lentisphaerae.  

PubMed

A mesophilic, obligately anaerobic, carbohydrate-fermenting bacterium, designated 8KG-4(T), was isolated from an upflow anaerobic sludge blanket reactor treating high-strength organic wastewater from salted vegetable production processes. Cells of strain 8KG-4(T) were non-motile, spherical and 0.7-1.5 µm in diameter (mean, 1.0 µm). Spore formation was not observed under any culture conditions tested. The strain grew optimally at 37 °C (range for growth 25-40 °C) and pH 7.0 (range, pH 6.5-7.5), and could grow fermentatively on glucose, ribose, xylose, galactose and sucrose. The main end products of glucose fermentation were acetate, ethanol and hydrogen. Organic acids, alcohols and amino acids were not utilized for growth. Yeast extract was not required for growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite and Fe(III) nitrilotriacetate were not used as terminal electron acceptors. The G+C content of the genomic DNA was 61.1 mol%. 16S rRNA gene sequence analysis revealed that the isolate represented a previously uncultured lineage at the subphylum level within the phylum Lentisphaerae known as 'WWE2 subgroup I'. The major cellular fatty acids were anteiso-C(15?:?0), iso-C(16?:?0), C(16?:?0) and anteiso-C(17?:?0). Respiratory quinones were not detected. The most abundant polar lipid of strain 8KG-4(T) was phosphatidylethanolamine. A novel genus and species, Oligosphaera ethanolica gen. nov., sp. nov., is proposed to accommodate strain 8KG-4(T) (?=?JCM 17152(T)?=?DSM 24202(T) ?=?CGMCC 1.5160(T)). In addition, we formally propose Oligosphaeria classis nov. and the subordinate taxa Oligosphaerales order nov. and Oligosphaeraceae fam. nov. PMID:22523166

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

2013-02-01

253

Nitrososphaera viennensis gen. nov., sp. nov., an aerobic and mesophilic, ammonia-oxidizing archaeon from soil and a member of the archaeal phylum Thaumarchaeota  

PubMed Central

A mesophilic, neutrophilic and aerobic, ammonia-oxidizing archaeon, strain EN76T, was isolated from garden soil in Vienna (Austria). Cells were irregular cocci with a diameter of 0.6–0.9 µm and possessed archaella and archaeal pili as cell appendages. Electron microscopy also indicated clearly discernible areas of high and low electron density, as well as tubule-like structures. Strain EN76T had an S-layer with p3 symmetry, so far only reported for members of the Sulfolobales. Crenarchaeol was the major core lipid. The organism gained energy by oxidizing ammonia to nitrite aerobically, thereby fixing CO2, but growth depended on the addition of small amounts of organic acids. The optimal growth temperature was 42 °C and the optimal pH was 7.5, with ammonium and pyruvate concentrations of 2.6 and 1 mM, respectively. The genome of strain EN76T had a DNA G+C content of 52.7 mol%. Phylogenetic analyses of 16S rRNA genes showed that strain EN76T is affiliated with the recently proposed phylum Thaumarchaeota, sharing 85?% 16S rRNA gene sequence identity with the closest cultivated relative ‘Candidatus Nitrosopumilus maritimus’ SCM1, a marine ammonia-oxidizing archaeon, and a maximum of 81?% 16S rRNA gene sequence identity with members of the phyla Crenarchaeota and Euryarchaeota and any of the other recently proposed phyla (e.g. ‘Korarchaeota’ and ‘Aigarchaeota’). We propose the name Nitrososphaera viennensis gen. nov., sp. nov. to accommodate strain EN76T. The type strain of Nitrososphaera viennensis is strain EN76T (?=?DSM 26422T?=?JMC 19564T). Additionally, we propose the family Nitrososphaeraceae fam. nov., the order Nitrososphaerales ord. nov. and the class Nitrososphaeria classis nov. PMID:24907263

Stieglmeier, Michaela; Klingl, Andreas; Alves, Ricardo J. E.; Rittmann, Simon K.-M. R.; Melcher, Michael; Leisch, Nikolaus

2014-01-01

254

Aminobacterium thunnarium sp. nov., a mesophilic, amino acid-degrading bacterium isolated from an anaerobic sludge digester, pertaining to the phylum Synergistetes.  

PubMed

A new Gram-positive-staining, non-sporulating, mesophilic, amino acid-degrading anaerobic bacterium, designated strain OTA 102T (T = type strain), was isolated from an anaerobic sequencing batch reactor treating cooking tuna wastewater. The cells were curved rods (0.6-2.5 x 0.5 µm) and occurred singly or in pairs. The strain was motile by means of one lateral flagellum. Strain OTA 102T grew at temperatures between 30° and 45°C (optimum 40°C), pH between 6.0 and 8.4 (optimum 7.2), and NaCl between 1-5% (optimum 2%). Strain OTA 102T required yeast extract for growth. Serine, threonine, glycine, cysteine, citrate, fumarate, ?-ketoglutarate and pyruvate were fermented. When cocultured with Methanobacterium formicicum as the hydrogen scavenger, strain OTA 102T oxidized alanine, valine, leucine, isoleucine, aspartate, tyrosine, histidine, methionine, histidine and asparagine. The genomic DNA G+C content of strain OTA 102T was 41.7 mol %. The main fatty acid was iso-C15:0 (58 %). Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain OTA 102T was related to Aminobacterium colombiense and Aminobacterium mobile (95.5 % and 95.2 % of similarity, respectively), phylum Synergistetes. On the basis of phylogenetic, genetic, and physiological characteristics, strain OTA 102T is proposed to be assigned to a new species of the genus Aminobacterium, A. thunnarium sp. nov.. The type strain is OTA 102T (=DSM 27500T= JCM 19320T). PMID:25406236

Hamdi, Olfa; Ben Hania, Wajdi; Postec, Anne; Bouallagui, Hassib; Hamdi, Moktar; Bonin, Patricia; Ollivier, Bernard; Fardeau, Marie-Laure

2014-11-18

255

Picomonas judraskeda Gen. Et Sp. Nov.: The First Identified Member of the Picozoa Phylum Nov., a Widespread Group of Picoeukaryotes, Formerly Known as ‘Picobiliphytes’  

PubMed Central

In 2007, a novel, putatively photosynthetic picoeukaryotic lineage, the ‘picobiliphytes’, with no known close eukaryotic relatives, was reported from 18S environmental clone library sequences and fluorescence in situ hybridization. Although single cell genomics later showed these organisms to be heterotrophic rather than photosynthetic, until now this apparently widespread group of pico-(or nano-)eukaryotes has remained uncultured and the organisms could not be formally recognized. Here, we describe Picomonas judraskeda gen. et sp. nov., from marine coastal surface waters, which has a ‘picobiliphyte’ 18S rDNA signature. Using vital mitochondrial staining and cell sorting by flow cytometry, a single cell-derived culture was established. The cells are biflagellate, 2.5–3.8×2–2.5 µm in size, lack plastids and display a novel stereotypic cycle of cell motility (described as the “jump, drag, and skedaddle”-cycle). They consist of two hemispherical parts separated by a deep cleft, an anterior part that contains all major cell organelles including the flagellar apparatus, and a posterior part housing vacuoles/vesicles and the feeding apparatus, both parts separated by a large vacuolar cisterna. From serial section analyses of cells, fixed at putative stages of the feeding cycle, it is concluded that cells are not bacterivorous, but feed on small marine colloids of less than 150 nm diameter by fluid-phase, bulk flow endocytosis. Based on the novel features of cell motility, ultrastructure and feeding, and their isolated phylogenetic position, we establish a new phylum, Picozoa, for Picomonas judraskeda, representing an apparently widespread and ecologically important group of heterotrophic picoeukaryotes, formerly known as ‘picobiliphytes’. PMID:23555709

Seenivasan, Ramkumar; Sausen, Nicole; Medlin, Linda K.; Melkonian, Michael

2013-01-01

256

Analysis of genome content evolution in pvc bacterial super-phylum: assessment of candidate genes associated with cellular organization and lifestyle.  

PubMed

The Planctomycetes, Verrucomicrobia, Chlamydiae (PVC) super-phylum contains bacteria with either complex cellular organization or simple cell structure; it also includes organisms of different lifestyles (pathogens, mutualists, commensal, and free-living). Genome content evolution of this group has not been studied in a systematic fashion, which would reveal genes underlying the emergence of PVC-specific phenotypes. Here, we analyzed the evolutionary dynamics of 26 PVC genomes and several outgroup species. We inferred HGT, duplications, and losses by reconciliation of 27,123 gene trees with the species phylogeny. We showed that genome expansion and contraction have driven evolution within Planctomycetes and Chlamydiae, respectively, and balanced each other in Verrucomicrobia and Lentisphaerae. We also found that for a large number of genes in PVC genomes the most similar sequences are present in Acidobacteria, suggesting past and/or current ecological interaction between organisms from these groups. We also found evidence of shared ancestry between carbohydrate degradation genes in the mucin-degrading human intestinal commensal Akkermansia muciniphila and sequences from Acidobacteria and Bacteroidetes, suggesting that glycoside hydrolases are transferred laterally between gut microbes and that the process of carbohydrate degradation is crucial for microbial survival within the human digestive system. Further, we identified a highly conserved genetic module preferentially present in compartmentalized PVC species and possibly associated with the complex cell plan in these organisms. This conserved machinery is likely to be membrane targeted and involved in electron transport, although its exact function is unknown. These genes represent good candidates for future functional studies. PMID:23221607

Kamneva, Olga K; Knight, Stormy J; Liberles, David A; Ward, Naomi L

2012-01-01

257

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

PubMed

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 degrees 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(14:0), a-C(15:0), C(16:1 omega 7c), and/or 2OH i-C(15:0), and C(16:0). The G+C content of the genomic DNA is 61 mol%. 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. PMID:15466527

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

2004-10-01

258

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. PMID:9106361

Wilson, R J; Williamson, D H

1997-01-01

259

An Inside Job: Hacking into Janus Kinase/Signal Transducer and Activator of Transcription Signaling Cascades by the Intracellular Protozoan Toxoplasma gondii  

PubMed Central

The intracellular protozoan Toxoplasma gondii is well known for its skill at invading and living within host cells. New discoveries are now also revealing the astounding ability of the parasite to inject effector proteins into the cytoplasm to seize control of the host cell. This review summarizes recent advances in our understanding of one such secretory protein called ROP16. This molecule is released from rhoptries into the host cell during invasion. The ROP16 molecule acts as a kinase, directly activating both signal transducer and activator of transcription 3 (STAT3) and STAT6 signaling pathways. In macrophages, an important and preferential target cell of parasite infection, the injection of ROP16 has multiple consequences, including downregulation of proinflammatory cytokine signaling and macrophage deviation to an alternatively activated phenotype. PMID:22104110

Bzik, David J.; Fox, Barbara A.; Butcher, Barbara A.

2012-01-01

260

An inside job: hacking into Janus kinase/signal transducer and activator of transcription signaling cascades by the intracellular protozoan Toxoplasma gondii.  

PubMed

The intracellular protozoan Toxoplasma gondii is well known for its skill at invading and living within host cells. New discoveries are now also revealing the astounding ability of the parasite to inject effector proteins into the cytoplasm to seize control of the host cell. This review summarizes recent advances in our understanding of one such secretory protein called ROP16. This molecule is released from rhoptries into the host cell during invasion. The ROP16 molecule acts as a kinase, directly activating both signal transducer and activator of transcription 3 (STAT3) and STAT6 signaling pathways. In macrophages, an important and preferential target cell of parasite infection, the injection of ROP16 has multiple consequences, including downregulation of proinflammatory cytokine signaling and macrophage deviation to an alternatively activated phenotype. PMID:22104110

Denkers, Eric Y; Bzik, David J; Fox, Barbara A; Butcher, Barbara A

2012-02-01

261

Whole animal and gill tissue oxygen uptake in the Eastern oyster, Crassostrea virginica: Effects of hypoxia, hypercapnia, air exposure, and infection with the protozoan parasite Perkinsus marinus 1 1 Contribution 157 of the Grice Marine Laboratory  

Microsoft Academic Search

The Eastern oyster, Crassostrea virginica, lives in shallow coastal waters and experiences many different environmental extremes including hypoxia, hypercapnia and air exposure and many oysters are infected with the protozoan parasite Perkinsus marinus. The effects of these conditions on oyster metabolism, as measured by oxygen uptake, were investigated. Mild hypercapnia had no effect on the ability of oysters to regulate

Libby L Willson; Louis E Burnett

2000-01-01

262

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

263

TOMACULOCYSTIS CORPULENTA N. GEN., N. SP. (APICOMPLEXA: EUGREGARINORIDA) PARASITIZING THE LITTLE YELLOW COCKROACH, CARIBLATTA LUTEA (BLATTODEA: ECTOBIIDAE) IN ALABAMA AND FLORIDA WITH RECOGNITION OF TOMACULOCYSTIS CYLINDROSA N. COMB. AND TOMACULOCYSTIS MUKUNDAI N. COMB. PARASITIZING ECTOBIID COCKROACHES IN INDIA.  

PubMed

Abstract Tomaculocystis corpulenta n. gen., n. sp. (Apicomplexa: Eugregarinorida: Septatorina: Gregarinidae) is described from populations of the little yellow cockroach, Cariblatta lutea (Blattodea: Ectobiidae), established in laboratory culture from samples collected in Alabama and Florida. Tomaculocystis n. gen. are differentiated from other members of Gregarina by a markedly elliptoid gametocyst inside a persistent, lomentiform hyaline epicyst; developmental organization and growth of the spore tubes from gametocyst surface tumidi; and, dehiscence by extrusion of non-chain forming oocysts through spore tubes that barely extend beyond the epicyst wall. Gregarina cylindrosa, Gregarina discocephala and Gregarina mukundai are recognized as members of Tomaculocystis and G. cylindrosa is recognized as the senior synonym of G. discocephala. Thus, Tomaculocystis cylindrosa n. comb. and Tomaculocystis mukundai n. comb. are formed. Species of Tomaculocystis are distinguished based on gamont deutomerite and oocyst shape and size. The oocysts of T. corpulenta are broadly dolioform, lack 4 polar knobs, and possess distinct, unique polar plates. Oocysts of all other known species in the genus are more oblong in shape, possess 4 polar knobs, and lack the distinct polar plates observed in the oocysts of T. corpulenta. Host utilization and geographic distribution among gregarine genera parasitizing the cockroach family Ectobiidae reveal a pattern of host-parasite specificity linking gregarine genera with ectobiidid subfamilies. Overall patterns suggest a hypothesis of european endemicy for Gamocystis, but hypotheses for the origin and radiation of Tomaculocystis or species of Gregarina infecting cockroaches are confounded by the cosmopolitan spread of pest cockroach species with humans. PMID:25153145

Clopton, Richard E

2014-08-25

264

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-C(13?:?0), iso-C(15?:?0), anteiso-C(15?:?0), C(18?:?1), C(19?:?1), C(20?:?1) and C(21?:?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

265

Phylogenetic relationships of Cryptosporidium determined by ribosomal RNA sequence comparison.  

PubMed

Reverse transcription of total cellular RNA was used to obtain a partial sequence of the small subunit ribosomal RNA of Cryptosporidium, a protist currently placed in the phylum Apicomplexa. The semi-conserved regions were aligned with homologous sequences in a range of other eukaryotes, and the evolutionary relationships of Cryptosporidium were determined by two different methods of phylogenetic analysis. The prokaryotes Escherichia coli and Halobacterium cuti were included as outgroups. The results do not show an especially close relationship of Cryptosporidium to other members of the phylum Apicomplexa. PMID:2332273

Johnson, A M; Fielke, R; Lumb, R; Baverstock, P R

1990-04-01

266

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 Central

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

267

Characterization of a cDNA encoding a cysteine-rich cell surface protein located in the flagellar pocket of the protozoan Trypanosoma brucei.  

PubMed Central

We have characterized a cDNA encoding a cysteine-rich, acidic integral membrane protein (CRAM) of the parasitic protozoa Trypanosoma brucei and Trypanosoma equiperdum. Unlike other membrane proteins of T. brucei, which are distributed throughout the cell surface, CRAM is concentrated in the flagellar pocket, an invagination of the cell surface of the trypanosome where endocytosis has been documented. Accordingly, CRAM also locates to vesicles located underneath the pocket, providing evidence of its internalization. CRAM has a predicted molecular mass of 130 kilodaltons and has a signal peptide, a transmembrane domain, and a 41-amino-acid cytoplasmic extension. A characteristic feature of CRAM is a large extracellular domain with a roughly 66-fold acidic, cysteine-rich 12-amino-acid repeat. CRAM is conserved among different protozoan species, including Trypanosoma cruzi, and CRAM has structural similarities with eucaryotic cell surface receptors. The most striking homology of CRAM is to the human low-density-lipoprotein receptor. We propose that CRAM functions as a cell surface receptor of different trypanosome species. Images PMID:1697030

Lee, M G; Bihain, B E; Russell, D G; Deckelbaum, R J; Van der Ploeg, L H

1990-01-01

268

Inbreeding and parasite sex ratios.  

PubMed Central

The breeding system of parasitic protozoa affects the evolution of drug resistance and virulence, and is relevant to disease diagnosis and the development of chemo- and immunotherapy. A major group of protozoan parasites, the phylum Apicomplexa, that includes the aetiological agents of malaria, toxoplasmosis and coccidiosis, all have dimorphic sexual stages. The sex ratio (proportion of males produced by parasites) is predicted to depend upon the inbreeding rate, and it has been suggested that sex-ratio data offer a relatively cheap and easy method for indirectly estimating inbreeding rates. Here, we exploit a new theoretical machinery to show that there are generally valid relationships between f, Wright's coefficient of inbreeding, and sex ratio, z(*), the generality being with respect to population structure. To focus the discussion, we concentrate on malaria and show that the previously derived result, f = 1 - 2z(*), does not depend on the artificial assumptions about population structure that were previously made. Not only does this justify the use of sex ratio as an indirect measure of f, but also we argue that it may actually be preferable to measure f by measuring sex ratios, rather than by measuring departures from Hardy-Weinberg genotypic proportions both in malaria and parasites more generally. PMID:11934369

Nee, Sean; West, Stuart A; Read, Andrew F

2002-01-01

269

[Serological survey of animal toxoplasmosis in Senegal.  

PubMed

Toxoplasma gondii is an obligate, intracellular, parasitic protozoan within the phylum Apicomplexa that causes toxoplasmosis in mammalian hosts (including humans) and birds. We used modified direct agglutination test for the screening of the animals' sera collected in Senegal. In total, 419 animals' sera have been studied: 103 bovines, 43 sheep, 52 goats, 63 horses, 13 donkeys and 145 dogs. The collection of sera was performed in four different regions of Senegal: Dakar, Sine Saloum, Kedougou and Basse Casamance from 2011 to 2013. We have revealed antibodies in 13% of bovines, 16% of sheep, 15% of goats, 30% of horses, 23% of donkeys and 67% of dogs. Private dogs from villages were more often to have the anti-Toxoplasma antibodies compared to security society-owned dogs from Dakar. It may be explained by different meal consumed by dogs (factory-produced meal for dogs from Dakar vs. irregular sources for village dogs). Intense circulation of T. gondii in the studied zone may explain the unusually high seroprevalence among horses and donkeys. Tropical climate with high temperature and humidity is favorable for the conservation of oocysts of T. gondii. Results presented here may contribute to the evaluation of the risks of toxoplasmosis in humans in Senegal. PMID:25307881

Davoust, B; Mediannikov, O; Sambou, M; Roqueplo, C; Demoncheaux, J -P; Perret, C; Guillot, J; Blaga, R

2014-10-11

270

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

271

Prevalence of Sarcocystis spp. and Hammondia spp. microcysts in esophagus tissue of sheep and cattle, emphasized on their morphological differences.  

PubMed

Sarcocystis and Hammondia are two obligatory protozoan parasites. These genera belong to cyst-forming coccidia group of the phylum Apicomplexa. They both need two different hosts to complete their life cycles. Felids and canids can act as definitive hosts, while herbivores, such as sheep and cattle, are the most important intermediate hosts. Reports verify that no important disease has been caused by Hammondia spp.; on the other hand, Sarcocystis spp. can cause some severe infectious disease in livestock industry such as abortion. Economic losses are another concern due to carcass condemnation during meat inspection in abattoirs and decrease in the quality and quantity of milk and wool production. Due to the Sarcocystis and Hammondia tissue cysts being similar, the distinction between these different genera is so important. In this study, the prevalence of Sarcocystis and Hammondia in the esophagus tissue of sheep and cattle slaughtered in one of the industrial abattoir in Iran was reported and an easy and rapid method for accurate diagnosing of Sarcocystis and Hammondia bradyzoites was explained. PMID:25082016

Rassouli, Maryam; Ahmadpanahi, Javad; Alvandi, Ayda

2014-10-01

272

Unusual Kinetic and Structural Properties Control Rapid Assembly and Turnover of Actin in the Parasite Toxoplasma gondiiD?  

PubMed Central

Toxoplasma is a protozoan parasite in the phylum Apicomplexa, which contains a number of medically important parasites that rely on a highly unusual form of motility termed gliding to actively penetrate their host cells. Parasite actin filaments regulate gliding motility, yet paradoxically filamentous actin is rarely detected in these parasites. To investigate the kinetics of this unusual parasite actin, we expressed TgACT1 in baculovirus and purified it to homogeneity. Biochemical analysis showed that Toxoplasma actin (TgACT1) rapidly polymerized into filaments at a critical concentration that was 3-4-fold lower than conventional actins, yet it failed to copolymerize with mammalian actin. Electron microscopic analysis revealed that TgACT1 filaments were 10 times shorter and less stable than rabbit actin. Phylogenetic comparison of actins revealed a limited number of apicomplexan-specific residues that likely govern the unusual behavior of parasite actin. Molecular modeling identified several key alterations that affect interactions between monomers and that are predicted to destabilize filaments. Our findings suggest that conserved molecular differences in parasite actin favor rapid cycles of assembly and disassembly that govern the unusual form of gliding motility utilized by apicomplexans. PMID:16319175

Sahoo, Nivedita; Beatty, Wandy; Heuser, John; Sept, David; Sibley, L. David

2006-01-01

273

Unique apicomplexan IMC sub-compartment proteins are early markers for apical polarity in the malaria parasite  

PubMed Central

Summary The phylum Apicomplexa comprises over 5000 intracellular protozoan parasites, including Plasmodium and Toxoplasma, that are clinically important pathogens affecting humans and livestock. Malaria parasites belonging to the genus Plasmodium possess a pellicle comprised of a plasmalemma and inner membrane complex (IMC), which is implicated in parasite motility and invasion. Using live cell imaging and reverse genetics in the rodent malaria model P. berghei, we localise two unique IMC sub-compartment proteins (ISPs) and examine their role in defining apical polarity during zygote (ookinete) development. We show that these proteins localise to the anterior apical end of the parasite where IMC organisation is initiated, and are expressed at all developmental stages, especially those that are invasive. Both ISP proteins are N-myristoylated, phosphorylated and membrane-bound. Gene disruption studies suggest that ISP1 is likely essential for parasite development, whereas ISP3 is not. However, an absence of ISP3 alters the apical localisation of ISP1 in all invasive stages including ookinetes and sporozoites, suggesting a coordinated function for these proteins in the organisation of apical polarity in the parasite. PMID:24244852

Poulin, Benoit; Patzewitz, Eva-Maria; Brady, Declan; Silvie, Olivier; Wright, Megan H.; Ferguson, David J. P.; Wall, Richard J.; Whipple, Sarah; Guttery, David S.; Tate, Edward W.; Wickstead, Bill; Holder, Anthony A.; Tewari, Rita

2013-01-01

274

Mass Spectrometric Analysis of l-Cysteine Metabolism: Physiological Role and Fate of l-Cysteine in the Enteric Protozoan Parasite Entamoeba histolytica  

PubMed Central

ABSTRACT l-Cysteine is essential for virtually all living organisms, from bacteria to higher eukaryotes. Besides having a role in the synthesis of virtually all proteins and of taurine, cysteamine, glutathione, and other redox-regulating proteins, l-cysteine has important functions under anaerobic/microaerophilic conditions. In anaerobic or microaerophilic protozoan parasites, such as Entamoeba histolytica, l-cysteine has been implicated in growth, attachment, survival, and protection from oxidative stress. However, a specific role of this amino acid or related metabolic intermediates is not well understood. In this study, using stable-isotope-labeled l-cysteine and capillary electrophoresis-time of flight mass spectrometry, we investigated the metabolism of l-cysteine in E. histolytica. [U-13C3, 15N]l-cysteine was rapidly metabolized into three unknown metabolites, besides l-cystine and l-alanine. These metabolites were identified as thiazolidine-4-carboxylic acid (T4C), 2-methyl thiazolidine-4-carboxylic acid (MT4C), and 2-ethyl-thiazolidine-4-carboxylic acid (ET4C), the condensation products of l-cysteine with aldehydes. We demonstrated that these 2-(R)-thiazolidine-4-carboxylic acids serve for storage of l-cysteine. Liberation of l-cysteine occurred when T4C was incubated with amebic lysates, suggesting enzymatic degradation of these l-cysteine derivatives. Furthermore, T4C and MT4C significantly enhanced trophozoite growth and reduced intracellular reactive oxygen species (ROS) levels when it was added to cultures, suggesting that 2-(R)-thiazolidine-4-carboxylic acids are involved in the defense against oxidative stress. PMID:25370494

Jeelani, Ghulam; Sato, Dan; Soga, Tomoyoshi; Watanabe, Haruo

2014-01-01

275

Kinetic characterization of methionine gamma-lyases from the enteric protozoan parasite Entamoeba histolytica against physiological substrates and trifluoromethionine, a promising lead compound against amoebiasis.  

PubMed

Methionine gamma-lyase (MGL) (EC 4.4.1.11), which is present in certain lineages of bacteria, plants, and protozoa but missing in mammals, catalyzes the single-step degradation of sulfur-containing amino acids (SAAs) to alpha-keto acids, ammonia, and thiol compounds. In contrast to other organisms possessing MGL, anaerobic parasitic protists, namely Entamoeba histolytica and Trichomonas vaginalis, harbor a pair of MGL isozymes. The enteric protozoon En. histolytica shows various unique aspects in its metabolism, particularly degradation of SAAs. Trifluoromethionine (TFM), a halogenated analog of Met, has been exploited as a therapeutic agent against cancer as well as against infections by protozoan organisms and periodontal bacteria. However, its mechanism of action remains poorly understood. In addition, the physiological significance of the presence of two MGL isozymes in these protists remains unclear. In this study, we compared kinetic parameters of the wild-type and mutants, engineered by site-directed mutagenesis, of the two MGL isotypes from En. histolytica (EhMGL1 and EhMGL2) for various potential substrates and TFM. Intracellular concentrations of l-Met and l-Cys suggested that these SAAs are predominantly metabolized by EhMGL1, not by EhMGL2. It is unlikely that O-acetyl-l-serine is decomposed by EhMGLs, given the kinetic parameters of cysteine synthase reported previously. Comparison of the wild-type and mutants revealed that the contributions of several amino acids implicated in catalysis differ between the two isozymes, and that the degradation of TFM is less sensitive to alterations of these residues than is the degradation of physiological substrates. These results support the use of TFM to target MGL. PMID:18199285

Sato, Dan; Yamagata, Wataru; Harada, Shigeharu; Nozaki, Tomoyoshi

2008-02-01

276

Characterization and transcriptional analysis of the promoter region of the Duffy blood group, chemokine receptor ( DARC) gene in cattle  

Microsoft Academic Search

The Duffy antigen is the only receptor for Plasmodium vivax, a hemoparasite of the phylum Apicomplexa and the cause of vivax malaria in humans. Resistance to this parasite in the majority of black African individuals and their descendents is due to a mutation in the gene promoter region, which blocks its transcription on erythrocytes. Regarding bovine babesiosis, it is known

T. L. Carvalho; P. E. M. Ribolla; R. A. Curi; L. S. L. S. Mota

2009-01-01

277

4-Bromophenacyl Bromide Specifically Inhibits Rhoptry Secretion during Toxoplasma Invasion  

Microsoft Academic Search

Toxoplasma gondii is a eukaryotic parasite of the phylum Apicomplexa that is able to infect a wide variety of host cells. During its active invasion process it secretes proteins from discrete secretory organelles: the micronemes, rhoptries and dense granules. Although a number of rhoptry proteins have been shown to be involved in important interactions with the host cell, very little

Sandeep Ravindran; Melissa B. Lodoen; Steven H. L. Verhelst; Matthew Bogyo; John C. Boothroyd; Ben L. Kelly

2009-01-01

278

Time-Lapse Video Microscopy of Gliding Motility in Toxoplasma gondii Reveals a Novel, Biphasic Mechanism of Cell Locomotionh V  

Microsoft Academic Search

Toxoplasma gondii is a member of the phylum Apicomplexa, a diverse group of intracellular parasites that share a unique form of gliding motility. Gliding is substrate dependent and occurs without apparent changes in cell shape and in the absence of traditional locomotory organelles. Here, we demonstrate that gliding is characterized by three distinct forms of motility: circular gliding, upright twirling,

Sebastian Håkansson; Hiroshi Morisaki; John Heuser; L. David Sibley

279

Living with the enemy or uninvited guests: functional genomics approaches to investigating host resistance or tolerance traits to a protozoan parasite, Theileria annulata, in cattle.  

PubMed

Many breeds of cattle with long histories of living in areas of endemic disease have evolved mechanisms that enable them to co-exist with specific pathogens. Understanding the genes that control tolerance and resistance could provide new strategies to improve the health and welfare of livestock. Around one sixth of the world cattle population is estimated to be at risk from one of the most debilitating tick-borne diseases of cattle, caused by the protozoan parasite, Theileria annulata. The parasite mainly infects cells of the myeloid lineage which are also the main producers of inflammatory cytokines. If an infectious or inflammatory insult is sufficiently great, inflammatory cytokines produced by macrophages enter the circulation and induce an acute phase proteins (APP) response. The Bos taurus Holstein breed produces higher and more prolonged levels of inflammatory cytokine induced APP than the Bos indicus Sahiwal breed in response to experimental infection with T. annulata. The Sahiwal exhibits significantly less pathology and survives infection, unlike the Holstein breed. Therefore, we hypothesised that the causal genes were likely to be expressed in macrophages and control the production of inflammatory cytokines. A functional genomics approach revealed that the transcriptome profile of the B. taurus macrophages was more associated with an inflammatory programme than the B. indicus macrophages. In particular the most differentially expressed gene was a member of the signal regulatory protein (SIRP) family. These are mainly expressed on myeloid cell surfaces and control inflammatory responses. Other differentially expressed genes included bovine major histocompatibility complex (MHC) (BoLA) class II genes, particularly BoLA DQ, and transforming growth factor (TGF)B2. We are now exploring whether sequence and functional differences in the bovine SIRP family may underlie the resistance or tolerance to T. annulata between the breeds. Potentially, our research may also have more general implications for the control of inflammatory processes against other pathogens. Genes controlling the balance between pathology and protection may determine how livestock can survive in the face of infectious onslaught. Next generation sequencing and RNAi methodologies for livestock species will bring new opportunities to link diversity at the genome level to functional differences in health traits in livestock species. PMID:22482839

Glass, Elizabeth J; Crutchley, Sarah; Jensen, Kirsty

2012-07-15

280

Expansion of host range as a driving force in the evolution of Toxoplasma  

Microsoft Academic Search

Toxoplasma gondii is a protozoan parasite in the phy- lum Apicomplexa. As such, it is related to many well- known pathogens such as those causing chicken cocci- diosis (Eimeria) and malaria (Plasmodium). Like all of these organisms, Toxoplasma is exquisitely well adapted to a single definitive host, in this case felines, in which it undergoes its sexual cycle. Where Toxoplasma

John C Boothroyd

2009-01-01

281

Acanthopleuribacter pedis gen. nov., sp. nov., a marine bacterium isolated from a chiton, and description of Acanthopleuribacteraceae fam. nov., Acanthopleuribacterales ord. nov., Holophagaceae fam. nov., Holophagales ord. nov. and Holophagae classis nov. in the phylum 'Acidobacteria'.  

PubMed

Strain FYK2218(T) was isolated from a specimen of the chiton Acanthopleura japonica, which had been collected from a beach on the Boso peninsula in Japan. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the strain belonged to the phylum 'Acidobacteria'. The most closely related type strains to strain FYK2218(T) were Holophaga foetida TMBS4(T) (83.6 % 16S rRNA gene sequence similarity) and Geothrix fermentans H-5(T) (83.6 %) in subdivision 8 of the 'Acidobacteria'. Cells of FYK2218(T) were motile, rod-shaped, Gram-negative, mesophilic and strictly aerobic. The G+C content of the strain was 56.7 mol%. The strain had isoprenoid quinones MK-6 and MK-7 as major components. Major fatty acids of the strain were iso-C(15 : 0), iso-C(17 : 0), C(16 : 0) and C(20 : 5)omega3c (cis-5,8,11,14,17-eicosapentaenoic acid). From the taxonomic data obtained in this study, it is proposed that the new marine isolate be placed into a novel genus and species named Acanthopleuribacter pedis gen. nov., sp. nov. within the new family, order and class Acanthopleuribacteraceae fam. nov., Acanthopleuribacterales ord. nov. and Holophagae classis nov. The family Holophagaceae fam. nov. is also described. The type strain of Acanthopleuribacter pedis is FYK2218(T) (=NBRC 101209(T) =KCTC 12899(T)). PMID:18984699

Fukunaga, Yukiyo; Kurahashi, Midori; Yanagi, Kensuke; Yokota, Akira; Harayama, Shigeaki

2008-11-01

282

DNA from protozoan parasites Babesia bovis, Trypanosoma cruzi, and T. brucei is mitogenic for B lymphocytes and stimulates macrophage expression of interleukin-12, tumor necrosis factor alpha, and nitric oxide.  

PubMed

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. 66:5423-5432, 1998). However, activation of macrophages by DNA from protozoan parasites has not been demonstrated. The present study was therefore conducted to determine whether DNA from the protozan parasites B. bovis, Trypanosoma cruzi, and T. brucei activates macrophages to secrete inflammatory mediators associated with protective immunity. DNA from Escherichia coli and all three parasites stimulated B-lymphocyte proliferation and increased macrophage production of interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-alpha), and nitric oxide (NO). Regulation of IL-12 and NO production occurred at the level of transcription. The amounts of IL-12, TNF-alpha, and NO induced by E. coli and protozoal DNA were strongly correlated (r2 > 0.9) with the frequency of CG dinucleotides in the genome, and immunostimulation by DNA occurred in the order E. coli > or = T. cruzi > T. brucei > B. bovis. Induction of inflammatory mediators by E. coli, T. brucei, and B. bovis DNA was dependent on the presence of unmethylated CpG dinucleotides. However, at high concentrations, E. coli and T. cruzi DNA-mediated macrophage activation was not inhibited following methylation. The recognition of protozoal DNA by B lymphocytes and macrophages may provide an important innate defense mechanism to control parasite replication and promote persistent infection. PMID:11254571

Shoda, L K; Kegerreis, K A; Suarez, C E; Roditi, I; Corral, R S; Bertot, G M; Norimine, J; Brown, W C

2001-04-01

283

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...

284

LIFE CYCLE OF CALYPTOSPORA FUNDULI (APICOMPLEXA: CALYPTOSPORIDAE)  

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). In this study, grass shrimp fed livers of Gulf killifish (Fundulus grandis) infected ...

285

INTRODUCTION The phylum Platyhelminthes (flatworms) consists of  

E-print Network

significantly to fundamental biomedical research in the areas of tissue regeneration, stem cell maintenance possess large populations of undifferentiated mesenchymal stem cells, the study of which could contribute and degenerative disorders. In most free- living species these stem cells, which are often referred to as neoblasts

Alvarado, Alejandro Sánchez

286

Predation on Horsehair Worms (Phylum Nematomorpha)  

Microsoft Academic Search

Field observations revealed cases of predation on horsehair worms by brown trout (Salmo trutta) in Maryland and Minnesota, a rock bass (Ambloplites rupestris) in Kentucky, and a crayfish in Wisconsin. Some fish contained more than one worm and may have consumed reproductive aggregations. In laboratory feeding trials with Gordius robustus, most individuals of several fish species either ignored the horsehair

Philip A. Cochran; Andrew P. Kinziger; William J. Poly

1999-01-01

287

Arthropods: Developmental diversity within a (super) phylum  

PubMed Central

The expression patterns of developmental genes provide new markers that address the homology of body parts and provide clues as to how body plans have evolved. Such markers support the idea that insect wings evolved from limbs but refute the idea that insect and crustacean jaws are fundamentally different in structure. They also confirm that arthropod tagmosis reflects underlying patterns of Hox gene regulation but they do not yet resolve to what extent Hox expression domains may serve to define segment homologies. PMID:10781039

Akam, Michael

2000-01-01

288

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. PMID:23281791

2012-01-01

289

Complete Gene Map of the Plastid-like DNA of the Malaria Parasite Plasmodium falciparum  

Microsoft Academic Search

Malaria parasites, and other parasitic protists of the Phylum Apicomplexa, carry a plastid-like genome with greatly reduced sequence complexity. This 35 kb DNA circle resembles the plastid DNA of non-photosynthetic plants, encoding almost exclusively components involved in gene expression. The complete gene map described here includes genes for duplicated large and small subunit rRNAs, 25 species of tRNA, three subunits

Paul W. Denny; Peter R. Preiser; Kaveri Rangachari; Kate Roberts; Anjana Roy; Andrea Whyte; Malcolm Strath; Daphne J. Moore; Peter W. Moore; Donald H. Williamson

1996-01-01

290

A Dibasic Motif in the Tail of a Class XIV Apicomplexan Myosin Is an Essential Determinant of Plasma Membrane Localization  

Microsoft Academic Search

Obligate intracellular parasites of the phylum Apicomplexa exhibit gliding motility, a unique form of substrate-dependent locomotion essential for host cell invasion and shown to involve the parasite actin cytoskeleton and myosin motor(s). Toxoplasma gondii has been shown to express three class XIV myosins, TgM-A, -B, and -C. We identified an additional such myosin, TgM-D, and completed the sequences of a

Christine Hettmann; Angelika Herm; Ariane Geiter; Bernd Frank; Eva Schwarz; Thierry Soldati; Dominique Soldati

2000-01-01

291

Two atypical L-cysteine-regulated NADPH-dependent oxidoreductases involved in redox maintenance, L-cystine and iron reduction, and metronidazole activation in the enteric protozoan Entamoeba histolytica.  

PubMed

We discovered novel catalytic activities of two atypical NADPH-dependent oxidoreductases (EhNO1/2) from the enteric protozoan parasite Entamoeba histolytica. EhNO1/2 were previously annotated as the small subunit of glutamate synthase (glutamine:2-oxoglutarate amidotransferase) based on similarity to authentic bacterial homologs. As E. histolytica lacks the large subunit of glutamate synthase, EhNO1/2 were presumed to play an unknown role other than glutamine/glutamate conversion. Transcriptomic and quantitative reverse PCR analyses revealed that supplementation or deprivation of extracellular L-cysteine caused dramatic up- or down-regulation, respectively, of EhNO2, but not EhNO1 expression. Biochemical analysis showed that these FAD- and 2[4Fe-4S]-containing enzymes do not act as glutamate synthases, a conclusion which was supported by phylogenetic analyses. Rather, they catalyze the NADPH-dependent reduction of oxygen to hydrogen peroxide and L-cystine to L-cysteine and also function as ferric and ferredoxin-NADP(+) reductases. EhNO1/2 showed notable differences in substrate specificity and catalytic efficiency; EhNO1 had lower K(m) and higher k(cat)/K(m) values for ferric ion and ferredoxin than EhNO2, whereas EhNO2 preferred L-cystine as a substrate. In accordance with these properties, only EhNO1 was observed to physically interact with intrinsic ferredoxin. Interestingly, EhNO1/2 also reduced metronidazole, and E. histolytica transformants overexpressing either of these proteins were more sensitive to metronidazole, suggesting that EhNO1/2 are targets of this anti-amebic drug. To date, this is the first report to demonstrate that small subunit-like proteins of glutamate synthase could play an important role in redox maintenance, L-cysteine/L-cystine homeostasis, iron reduction, and the activation of metronidazole. PMID:20592025

Jeelani, Ghulam; Husain, Afzal; Sato, Dan; Ali, Vahab; Suematsu, Makoto; Soga, Tomoyoshi; Nozaki, Tomoyoshi

2010-08-27

292

Emerging Food- and Waterborne Protozoan Diseases  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cryptosporidium, Cyclospora and Toxoplasma are related apicomplexan parasites transmitted to humans worldwide through ingestion of contaminated food and drinking water. Of 15 species of Cryptosporidium- C parvum, C. hominis, C and C. meleagridis are the most prevalent infections in humans and the la...

293

Molecular Phylogeny of Centrohelid Heliozoa, a Novel Lineage of Bikont Eukaryotes That Arose by Ciliary Loss  

Microsoft Academic Search

  Abstract\\u000a \\u000a Recent molecular and cellular evidence indicates that eukaryotes comprise three major lineages: the probably ancestrally uniciliate\\u000a protozoan phylum Amoebozoa; the ancestrally posteriorly uniciliate opisthokont clade (animals, Choanozoa, and fungi); and\\u000a a very diverse ancestrally biciliate clade, the bikonts—plants, chromalveolates, and excavate and rhizarian Protozoa. As Heliozoa\\u000a are the only eukaryote phylum not yet placed on molecular sequence trees, we

Thomas Cavalier-Smith; Ema E.-Y. Chao

2003-01-01

294

Developmental biology of Cystoisospora (Apicomplexa: Sarcocystidae) monozoic tissue cysts  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tissue cyst stages are an intriguing aspect of the developmental cycle and transmission of members of the Family Sarcocystidae. Tissue cyst stages of the genera Toxoplasma, Hammondia, Neospora, Besnoitia, and Sarcocystis contain many infectious stages (bradyzoites).The tissue cyst stage of Cystoisos...

295

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...

296

Two new eimerians (Apicomplexa) from insectivorous mammals in Madagascar.  

PubMed

Fecal samples from 126 insectivorous mammals in Madagascar were collected between spring 1999 and fall 2001. In the Afrosoricida, 21 species in 5 genera were sampled, including 17 species of Microgale (31/96, 32% infected), Hemicentetes semispinosus (1/2, 50%), Oryzorictes hova (1/5, 20%), Setifer setosus (8/13, 61.5%), and Tenrec ecaudatus (5/8, 62.5%); in the Soricomorpha, only Suncus murinus was examined and 1/2 (50%) were infected. Two morphotypes of eimeriid oocysts, representing 2 presumptive new species, were found in 47 (37%) infected animals; only 2 afrosoricid hosts (2% of all hosts, 4% of infected hosts) had both oocyst morphotypes. Sporulated oocysts of the first morphotype, Eimeria tenrececaudata n. sp., are subspheroidal, 18.8 × 17.4 (17-22 × 15-20), with a length?width ratio (L/W) of 1.1 (1.0-1.2); they lack a micropyle but may contain 0-2 polar granules and a single, small round oocyst residuum, 3 × 2.3. Sporocysts are lemon-shaped, 9.9 × 6.6 (9-11 × 5-8), with a L/W of 1.5 (1.2-2.0); they have a prominent, slightly flattened Stieda body and a substieda body but lack a parastieda body. The sporocyst residuum consists of only a few granules between the sporozoites, which are sausage-shaped and have a large posterior refractile body. Oocysts of the second morphotype, Eimeria setifersetosa n. sp. are spheroidal to subspheroidal, 30.1 × 28.6 (27-34 × 25-34), with a L/W of 1.1 (1.0-1.2); they lack both micropyle and oocyst residuum, but 1-2 polar granules are usually present. Sporocysts are subspheroidal to broadly ellipsoidal, 9.6 × 7.3 (9-11 × 6-8), with a L/W of 1.3 (1.1-1.7); they have a broad Stieda body, lack sub- and parastieda bodies, and have a residuum of a few granules scattered throughout the sporocyst. Sporozoites were not clearly defined, but what seemed to be a single large refractile body is seen, presumably in each sporozoite. PMID:21506791

Couch, Lee; Laakkonen, Juha; Goodman, Steven; Duszynski, Donald W

2011-04-01

297

Cryptosporidium xiaoi n. sp. (Apicomplexa: Cryptosporidiidae) in sheep (Ovis aries)  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new species, Cryptosporidium xiaoi, is described from sheep. Oocysts of C. xiaoi, previously identified as the Cryptosporidium bovis-like genotype and as the ovine genotype from sheep in Australia and the United States are recorded as such in GenBank (AY587166, EU203216, DQ182597, AY741309, and DQ...

298

Besnoitia oryctofelisi n. sp. (Protozoa: Apicomplexa) from domestic rabbits.  

PubMed

A species of Besnoitia from naturally infected rabbits from Argentina was propagated experimentally in mice, gerbils, rabbits, cats, and cell cultures. Cats fed tissue cysts from rabbits shed oocysts with a prepatent period of nine to 13 days. Sporulated oocysts were infective to gerbils, rabbits, outbred Swiss Webster and interferon gamma gene knockout mice. Bradyzoites were infective orally to gerbils and cats. Tachyzoites were successfully cultivated and maintained in vitro in bovine monocytes and African green monkey kidney cells. Schizonts were seen in the lamina propria of the small intestine of cats fed tissue cysts; the largest ones measured 52 x 45 microm. Schizonts were also present in mesenteric lymph nodes, livers, and other extra-intestinal organs of cats fed tissue cysts. Oocysts were 10-14 x 10-13 microm in size. This rabbit-derived species of Besnoitia resembled B. darlingi of the North American opossum, Didelphis virginiana with an opossum-cat cycle, but it was not transmissible to D. virginiana, and B. darlingi of opossums was not transmissible to rabbits. Based on biological, serological, antigenic, and molecular differences between the rabbit and the opossum Besnoitia, a new name, B. oryctofelisi is proposed for the parasite from domestic rabbits from Argentina. PMID:12879849

Dubey, J P; Sreekumar, C; Lindsay, D S; Hill, D; Rosenthal, B M; Venturini, L; Venturini, M C; Greiner, E C

2003-06-01

299

Cryptosporidium erinacei n. sp. (Apicomplexa: Cryptosporidiidae) in hedgehogs.  

PubMed

The morphological, biological, and molecular characteristics of Cryptosporidium hedgehog genotype are described, and the species name Cryptosporidium erinacei n. sp. is proposed to reflect its specificity for hedgehogs under natural and experimental conditions. Oocysts of C. erinacei are morphologically indistinguishable from Cryptosporidium parvum, measuring 4.5-5.8 ?m (mean=4.9 ?m) × 4.0-4.8 ?m (mean=4.4 ?m) with a length to width ratio of 1.13 (1.02-1.35) (n=100). Oocysts of C. erinacei obtained from a naturally infected European hedgehog (Erinaceus europaeus) were infectious for naïve 8-week-old four-toed hedgehogs (Atelerix albiventris); the prepatent period was 4-5 days post infection (DPI) and the patent period was longer than 20 days. C. erinacei was not infectious for 8-week-old SCID and BALB/c mice (Mus musculus), Mongolian gerbils (Meriones unguiculatus), or golden hamsters (Mesocricetus auratus). Phylogenetic analyses based on small subunit rRNA, 60 kDa glycoprotein, actin, Cryptosporidium oocyst wall protein, thrombospondin-related adhesive protein of Cryptosporidium-1, and heat shock protein 70 gene sequences revealed that C. erinacei is genetically distinct from previously described Cryptosporidium species. PMID:24529828

Kvá?, Martin; Hofmannová, Lada; Hlásková, Lenka; Kv?to?ová, Dana; Vítovec, Ji?í; McEvoy, John; Sak, Bohumil

2014-03-17

300

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

301

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. PMID:24892871

Leung, Jacqueline M.; Tran, Fanny; Pathak, Ravindra B.; Poupart, Séverine; Heaslip, Aoife T.; Ballif, Bryan A.; Westwood, Nicholas J.; Ward, Gary E.

2014-01-01

302

Lysine Acetyltransferase GCN5b Interacts with AP2 Factors and Is Required for Toxoplasma gondii Proliferation  

PubMed Central

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; Ali Hakimi, Mohamed; Kim, Kami; Sullivan, William J.

2014-01-01

303

Phylum Porifera Ancient group of animals that dates  

E-print Network

on bacteria and protists · Mainly marine (~7000 species), but some in freshwater (~300 species). · ~27 is intracellular · Wastes are eliminated by diffusion · Gas exchange is by diffusion Defining Characteristic cells. Cells signal each other by DIFFUSION of chemical messages · Myocytes ("muscle cells") regulate

Cochran-Stafira, D. Liane

304

STATUS AND APPLICATIONS OF ECHINOID (PHYLUM ECHINODERMATA) TOXICITY TEST METHODS  

EPA Science Inventory

The use of echinoderms for toxicity testing has focused primarily on sea urchins and sand dollars (Strongylocentrolus purpuratus, Arbacia punctulata, Lytechinus pictus, and Dendraster excentricus, for example). he status and relative sensitivity of various test methods are descri...

305

A QUICK REVIEW OF SCHISTOSOMES They are flatworms (Phylum  

E-print Network

vehicles, Lake Victoria, Kisumu, Kenya Giving your younger brother a bath - Ukerewe Island, Lake Victoria? Near Rio de Janeiro, Brazil Near Belo Horizonte,Brazil A stream in Kenya Lake Victoria, Tanzania #12

Loker, Eric "Sam"

306

Periderm Ultrastructure of a Species of Monograptus (Phylum Hemichordata)  

Microsoft Academic Search

The longitudinal strengthening rods of the prosicular (larval) stage of the colony of Monograptus riccartonensis Lapworth are shown to be relatively high, sharp ridges, and are themselves supported by low-angled buttresses. The longitudinal rods are external to the main body of prosicular periderm which consists of a dense connecting network of short rods. The prosicular spiral line structure is probably

R. B. Rickards; P. J. W. Hyde; D. H. Krinsley

1971-01-01

307

Fine structure of eyespots in tornarian larvae (Phylum: Hemichordata)  

Microsoft Academic Search

The eyespots of tornariae of enteropneusts (Ptychodera flava from Hawaiian waters and an unknown species from southern California) were studied by electron microscopy. An ocellus is composed of two types of cells: sensory and supportive. The former is characterized by a bulbous cilium (with 9+2 axoneme) at its distal end, one or sometimes two arrays of microvilli from its sides

Jean L. Brandenburger; Robert M. Woollacott; Richard M. Eakin

1973-01-01

308

Status and applications of echinoid (phylum echinodermata) toxicity test methods  

SciTech Connect

The use of echinoderms for toxicity testing has focused primarily on sea urchins and sand dollars (Strongylocentrotus purpuratus, Arbacia punctulata, Lytechinus pictus, and Dendraster excentricus, for example). The status and relative sensitivity of various test methods are described. The most frequently used test methods consist of short-term exposures of sea urchin sperm or embryos; these tests can be easily conducted at all times of the year by using species with complementary spawning cycles or laboratory conditioned populations of a single species. Data from reference toxicant and effluent toxicity tests are summarized. Information on the precision and sensitivity of echinoid test methods are limited and preclude rigorous comparisons with other test methods. The available data indicate that the sensitivity and precision of these methods are comparable to short-term chronic methods for other marine invertebrates and fish. Recent application of the sperm test in toxicity identification evaluations (TIEs) and studies of effluent toxicity decay and sediment toxicity illustrate the versatility of this rapid (10 to 60 min exposure) test method. Embryo tests typically use a 48 to 96 h exposure period and measure the occurrence of embryo malformations. Most recent applications of the embryo test have been for the assessment of sediment elutriate toxicity. Adult echinoderms are not frequently used to assess effluent or receiving water toxicity. Recent studies have had success in using the adult life stage of urchins and sand dollars to assess the effects of contaminated sediment on growth, behavior, and bioaccumulation.

Bay, S.; Burgess, R.; Nacci, D.

1993-01-01

309

The apicoplast: a red alga in human parasites.  

PubMed

Surprisingly, some of the world's most dangerous parasites appear to have had a benign photosynthetic past in the ocean. The phylum Apicomplexa includes the causative agents of malaria and a number of additional human and animal diseases. These diseases threaten the life and health of hundreds of millions each year and pose a tremendous challenge to public health. Recent findings suggest that Apicomplexa share their ancestry with diatoms and kelps, and that a key event in their evolution was the acquisition of a red algal endosymbiont. A remnant of this endosymbiont is still present today, albeit reduced to a small chloroplast-like organelle, the apicoplast. In the present chapter, I introduce the remarkably complex biology of this organelle. The apicoplast is bounded by four membranes, and these membranes trace their ancestry to three different organisms. Intriguingly, this divergent ancestry is still reflected in their molecular makeup and function. We also pursue the raison d'être of the apicoplast. Why did Apicomplexa retain a chloroplast when they abandoned photosynthesis for a life as obligate parasites? The answer to this question appears to lie in the profound metabolic dependence of the parasite on its endosymbiont. This dependence may prove to be a liability to the parasite. As humans lack chloroplasts, the apicoplast has become one of the prime targets for the development of parasite-specific drugs. PMID:22023445

Striepen, Boris

2011-01-01

310

Evolutionary ecology of transmission strategies in protozoan parasites   

E-print Network

In recent years there has been growing interest in applying frameworks from evolutionary ecology to understand infectious disease. It is becoming increasingly apparent that the interactions between parasites within the ...

Pollitt, Laura C.

2011-11-24

311

Search for blood protozoans in the American woodcock  

USGS Publications Warehouse

Smears were prepared from heart blood of 55 woodcock collected in central Maine between spring and fall, 1972 and 1973. Peripheral blood taken from the wings of 41 of these birds also was examined. Examination of stained films revealed no infected blood cells. Samples of heart blood from 35 of the 41 woodcock were injected into young ducks, quail, and a gull. Plasmodia were not seen in inoculated birds.

Krohn, W.B.; Hynson, J.R.

1975-01-01

312

IMP Dehydrogenase from the Protozoan Parasite Toxoplasma gondii  

PubMed Central

The opportunistic apicomplexan parasite Toxoplasma gondii damages fetuses in utero and threatens immunocompromised individuals. The toxicity associated with standard antitoxoplasmal therapies, which target the folate pathway, underscores the importance of examining alternative pharmacological strategies. Parasitic protozoa cannot synthesize purines de novo; consequently, targeting purine salvage enzymes is a plausible pharmacological strategy. Several enzymes critical to purine metabolism have been studied in T. gondii, but IMP dehydrogenase (IMPDH), which catalyzes the conversion of IMP to XMP, has yet to be characterized. Thus, we have cloned the gene encoding this enzyme in T. gondii. Northern blot analysis shows that two IMPDH transcripts are present in T. gondii tachyzoites. The larger transcript contains an open reading frame of 1,656 nucleotides whose deduced protein sequence consists of 551 amino acids (TgIMPDH). The shorter transcript is an alternative splice product that generates a 371-amino-acid protein lacking the active-site flap (TgIMPDH-S). When TgIMPDH is expressed as a recombinant protein fused to a FLAG tag, the fusion protein localizes to the parasite cytoplasm. Immunoprecipitation with anti-FLAG was employed to purify recombinant TgIMPDH, which converts IMP to XMP as expected. Mycophenolic acid is an uncompetitive inhibitor relative to NAD+, with a intercept inhibition constant (Kii) of 0.03 ± 0.004 ?M. Tiazofurin and its seleno analog were not inhibitory to the purified enzyme, but adenine dinucleotide analogs such as TAD and the nonhydrolyzable ?-methylene derivatives of TAD or SAD were inhibitory, with Kii values 13- to 60-fold higher than that of mycophenolic acid. PMID:15917510

Sullivan, William J.; Dixon, Stacy E.; Li, Catherine; Striepen, Boris; Queener, Sherry F.

2005-01-01

313

IMP Dehydrogenase from the Protozoan Parasite Toxoplasma gondii  

Microsoft Academic Search

The opportunistic apicomplexan parasite Toxoplasma gondii damages fetuses in utero and threatens immu- nocompromised individuals. The toxicity associated with standard antitoxoplasmal therapies, which target the folate pathway, underscores the importance of examining alternative pharmacological strategies. Parasitic protozoa cannot synthesize purines de novo; consequently, targeting purine salvage enzymes is a plausible pharmacological strategy. Several enzymes critical to purine metabolism have been

Stacy E. Dixon; Catherine Li; Boris Striepen; Sherry F. Queener

2005-01-01

314

Temporal analysis of protozoan lysis in a microfluidic device.  

PubMed

A microfluidic device was fabricated and characterized for studying cell lysis of Arcella vulgaris, a nonpathogenic amoeba, over time. The device contains a series of chambers which capture cells allowing them to be subsequently exposed to a constant flow of biocidal agent. With this microfluidic system, individual cells are observed as they undergo lysis. This allows high-throughput measurements of individual lysis events, which are not possible with conventional techniques. Differences in lysis and decay times for Arcella were seen at different flow rates and concentrations of benzalkonium chloride, a biocidal detergent. The efficacy of benzalkonium chloride, chlorhexidine digluconate, phenol, sodium dodecyl sulfate, and Triton X-100 were compared, revealing information on their mechanisms of action. The presented device allows cell capture, controlled exposure to chemical biocides, and observation of lysis with single-cell resolution. Observations at the single cell level give insight into the mechanistic details of the lysis of individual Arcella cells vs. the population; decay times for individual Arcella cells were much shorter when compared to a population of 15 cells. PMID:19967116

Santillo, Michael F; Heien, Michael L; Ewing, Andrew G

2009-10-01

315

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. PMID:20930074

Barratt, J. L. N.; Harkness, J.; Marriott, D.; Ellis, J. T.; Stark, D.

2010-01-01

316

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

317

Haemogregarine specificity in two communities of Florida snakes, with descriptions of six new species of Hepatozoon (Apicomplexa: Hepatozoidae) and a possible species of Haemogregarina (Apicomplexa: Haemogregarinidae).  

PubMed

Five species of snakes in Florida, from Palm Beach County in the south and Alachua County 450 km to the north, occur in similar habitat but have distinctive Hepatozoon species characteristic of each host species. In Palm Beach County, Diadophis punctatus is host to Hepatozoon punctatus n. sp., Thamnophis sauritus sackenii to Hepatozoon sauritus n. sp., and Nerodia fasciata pictiventris to Hepatozoon pictiventris n. sp. In Alachua County, N. fasciata pictiventris is parasitized by Hepatozoon fasciatae n. sp., Seminatrix p. pygaea by Hepatozoon seminatrici n. sp., and Thamnophis s. sirtalis by Hepatozoon sirtalis n. sp. Each Hepatozoon sp. has distinctive gamonts and sporogonic characters and, in the 4 species where known, meronts. Nerodia floridana is host to Haemogregarina floridana n. sp. in both localities, with generic identification tentative, based upon presence of erythrocytic meronts. The presence of sporocysts in the proboscis of 31% of Aedes aegypti infected by H. pictiventris is the first report of infective stages of a reptilian Hepatozoon species within the mouthparts of a dipteran vector. This study suggests that in Florida, at least, the diversity of the Hepatozoon community not only equals but probably exceeds the diversity of the snake communities present, and that host specificity in nature may be much greater than that postulated from previous studies. PMID:11534655

Telford, S R; Wozniak, E J; Butler, J F

2001-08-01

318

Kingdoms Protozoa and Chromista and the eozoan root of the eukaryotic tree.  

PubMed

I discuss eukaryotic deep phylogeny and reclassify the basal eukaryotic kingdom Protozoa and derived kingdom Chromista in the light of multigene trees. I transfer the formerly protozoan Heliozoa and infrakingdoms Alveolata and Rhizaria into Chromista, which is sister to kingdom Plantae and arguably originated by synergistic double internal enslavement of green algal and red algal cells. I establish new subkingdoms (Harosa; Hacrobia) for the expanded Chromista. The protozoan phylum Euglenozoa differs immensely from other eukaryotes in its nuclear genome organization (trans-spliced multicistronic transcripts), mitochondrial DNA organization, cytochrome c-type biogenesis, cell structure and arguably primitive mitochondrial protein-import and nuclear DNA prereplication machineries. The bacteria-like absence of mitochondrial outer-membrane channel Tom40 and DNA replication origin-recognition complexes from trypanosomatid Euglenozoa roots the eukaryotic tree between Euglenozoa and all other eukaryotes (neokaryotes), or within Euglenozoa. Given their unique properties, I segregate Euglenozoa from infrakingdom Excavata (now comprising only phyla Percolozoa, Loukozoa, Metamonada), grouping infrakingdoms Euglenozoa and Excavata as the ancestral protozoan subkingdom Eozoa. I place phylum Apusozoa within the derived protozoan subkingdom Sarcomastigota. Clarifying early eukaryote evolution requires intensive study of properties distinguishing Euglenozoa from neokaryotes and Eozoa from neozoa (eukaryotes except Eozoa; ancestrally defined by haem lyase). PMID:20031978

Cavalier-Smith, Thomas

2010-06-23

319

CDPKs of Cryptosporidium parvum--stage-specific expression in vitro.  

PubMed

Cryptosporidium parvum is a zoonotic agent that bears a high risk for the health of particularly immunocompromised humans and animals. As currently available drugs and therapies against cryptosporidiosis do not turn out satisfactory, more intensive research on the control of this parasite is necessary. The genus Cryptosporidium is unique within the phylum Apicomplexa as its localisation is intracellular but extracytoplasmatic. Infection of host cells is initially a parasite-driven process, but the signalling events and their downstream actions within Cryptosporidium are poorly understood. Calcium-dependent protein kinases (CDPKs) are probably involved in the regulation of invasion and egress. Previously described in plants, algae and other Apicomplexa, CDPKs are not found in vertebrates. They are thus promising targets for pharmaceutical intervention. While CDPK1 is well characterised in Toxoplasma gondii (TgCDPK1) and Plasmodium falciparum (PfCDPK1), only little information exists about the expression and function of CDPK in C. parvum. Here, we describe results of the in silico analysis of seven CpCDPKs. Five CpCDPKs contain potential sites for N-myristoylation and N-palmitoylation. In a nested 3' rapid amplification of cDNA ends (RACE)-PCR, expression of six CpCDPKs resulted in distinct bands in infected cell cultures and extracts of freshly excysted sporozoites. The length of the 3' untranslated region (3' UTR) is described as well. Our results indicate CDPK expression to be stage specific on the mRNA level. PMID:24810092

Etzold, Manja; Lendner, Matthias; Daugschies, Arwid; Dyachenko, Viktor

2014-07-01

320

A new species of Sarcocystis (Apicomplexa: Sarcocystidae) from the black bear (Ursus americanus).  

PubMed

Infection with Sarcocystis species is common in herbivores but is rare in bears. Histological sections of 374 black bears (Ursus americanus) from Pennsylvania were examined for sarcocysts. In total, 3 sarcocysts were found in 3 bears, with 1 sarcocyst per section. Sarcocysts from 2 bears were considered a new species, Sarcocystis ursusi. Sarcocysts of S. ursusi n. sp. were microscopic and contained only bradyzoites. By light microscopy, the sarcocyst wall was thin (< 0.5 microm thick) and had minute serrations. Ultrastructurally, the serrations on the sarcocyst wall consisted of villar protrusions (Vp) that were mostly 0.5 microm long. The Vp had bundles of electron-dense microtubules that were as wide as long; these microtubules extended deep into the ground substance layer, a feature that distinguished this species from unnamed sarcocysts from black bear. Bradyzoites were 4.8-6.0 microm long. The sarcocyst from the third bear was structurally different from S. ursusi; its sarcocyst wall was approximately 2 microm thick and had finger-like villi on the cyst wall giving the sarcocyst wall a striated appearance. PMID:18564883

Dubey, J P; Humphreys, G; Fritz, D

2008-04-01

321

A description of Isospora amphiboluri (Apicomplexa: Eimeriidae) from the inland bearded dragon, Pogona vitticeps (Sauria: Agamidae).  

PubMed

Fecal samples from 50 captive inland bearded dragons, Pogona vitticeps (Ahl, 1926), bred in California, were examined for coccidian parasites. Sixteen (32%) of the lizards were found to be passing oocysts of Isospora amphiboluri Cannon, 1967, previously described from bearded dragons Pogona barbata (Cuvier, 1829) from Australia. Sporulated oocytes were spherical to subspherical, 25.3 x 25.1 (23-26 x 23-26) microns, with a shape index (length/width) of 1.0 (1.0-1.1). A micropyle, oocyst residuum, and polar granule were absent. Sporocyts were ovoidal, 17.0 x 11.4 (16-18 x 11-12) microns, with a shape index of 1.5 (1.4-1.7). A sporocyst residuum, Stieda, and substieda bodies were present, but parastieda bodies were absent. Sporozoites were elongated, 13.9 x 3.5 (12-15 x 3-4) microns in situ, containing spherical anterior and posterior refractile bodies. The occurrence of I. amphiboluri in P. vitticeps is a new host and geographic record for the parasite. Photomicrographs of the oocysts and endogenous life cycle stages of I. amphiboluri are presented for the first time. PMID:7707208

McAllister, C T; Upton, S J; Jacobson, E R; Kopit, W

1995-04-01

322

A REDESCRIPTION OF CRYPTOSPORIDIUM GALLI PAVLASEK 1999 (APICOMPLEXA: CRYPSTOPORIDIIDAE) FROM BIRDS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cryptosporidium galli Pavlasek, 1999 is described from the faeces of birds adding molecular and biological data. Oocysts are ellipsoidal, are passed fully sporulated, lack sporocysts, and measure 8.25 x 6.3 m (range 8.0 ¿ 8.5 X 6.2 ¿ 6.4 m) with a length to width ratio 1.30 (n=50). Oocysts are stru...

323

Ultrastructural development of the sarcocyst of Sarcocystis rauschorum (Apicomplexa: Sarcocystidae) in the varying lemming Dicrostonyx richardsoni.  

PubMed

The development of the sarcocyst of Sarcocystis rauschorum in its intermediate host was studied. Lemmings were orally administered sporocysts of S. rauschorum obtained from snowy owls (Nyctea scandiaca). Beginning at 9 days postinoculation (DPI) and at various intervals to 84 DPI, skeletal muscle tissue taken from the infected lemmings was examined by electron microscopy. At 9 DPI the sarcocysts contained few metrocytes and the cyst wall was flat. The metrocytes underwent endodyogeny, and within a few days the cyst wall of the rapidly growing sarcocyst developed numerous tubulovesicular invaginations into the electron-dense layer, and the wall had a few irregular infoldings. By 21 DPI, banana-shaped bradyzoites appeared, and by 84 DPI the mature cysts were filled with bradyzoites in groups subdivided by septa and by deep infoldings of the cyst wall. The fine structure of the wall remained simple throughout maturation, with no conspicuous invagination or protrusion. The sarcocyst produced in response to S. rauschorum is unlike those from many species of Sarcocystis, which have complex walls that change markedly as the sarcocysts mature; however, its simple appearance is similar to other species that have rodents as intermediate hosts and raptorial birds as definitive hosts. PMID:2498495

Friesen, D L; Cawthorn, R J; Speer, C A; Brooks, R J

1989-06-01

324

GOUSSIA GIRELLAE N. SP. (APICOMPLEXA: EIMERIORINA) IN THE OPALEYE, 'GIRELLA NIGRICANS' (JOURNAL VERSION)  

EPA Science Inventory

Goussia girellae n. sp. is described from the opaleye fish, Girella nigricans. Merogonic stages were observed in the apices of intestinal epithelial cells, in the lamina propria, and in extraintestinal sites including liver, gills, and spleen. Gamonts were observed in the intesti...

325

First report of Hepatozoon (Apicomplexa: Adeleorina) in caecilians, with description of a new species.  

PubMed

Hepatozoon spp. are identified for the first time in the amphibian order Gymnophiona, or caecilians, from the Seychelles island of Silhouette. Estimate of relationships derived from partial 18S rRNA gene sequences indicate these are not related to Hepatozoon spp. from frogs or to other Hepatozoon spp. from reptiles in the Seychelles. Assessment of mature gamonts from blood smears indicate that these can be recognized as a new species, Hepatozoon seychellensis n. sp. PMID:23971488

Harris, D James; Damas-Moreira, Isabel; Maia, João P M C; Perera, Ana

2014-02-01

326

A new eimeriid (Apicomplexa) species from endangered Attwater's prairie chickens (Tympanuchus cupido attwateri) in Texas.  

PubMed

The Attwater's prairie chicken (APC; Tympanuchus cupido attwateri Bendire, 1894) has been a federally listed endangered species since 1967. Several captive propagation programs consisting of small populations are being used to keep this species from extinction. Fecal samples were collected from APCs in April 2007 and again in August 2008 from 2 separate captive propagation facilities in Texas after clinical signs of coccidiosis were observed. One Eimeria species was observed (Eimeria attwateri), which we describe as a putative new species. Sporulated oocysts are ellipsoidal, 30.0 × 18.4 (27.4-31.3 × 16.0-22.4) µm. Oocysts have a smooth wall 0.7 µm thick and lack both a micropyle and oocyst residuum, but 1 ellipsoidal polar granule is present, 2.3 × 1.9 (2.1-2.4 × 1.7-2.0) µm. Sporocysts have a nipple-like Stieda body with a rounded opposite end and are 14.0 × 7.1 (10.2-16.8 × 6.0-9.2) µm. The sporocysts contain a sporocyst residuum usually consisting of 2-4 dispersed globules, and each sporozoite contains 2 large posterior spheroid refractile bodies 3.4 µm wide. Nucleotide sequence amplified from the 18S rDNA does not match any DNA sequence information for publicly available Eimeria species, and phylogenetic reconstructions place this species with other eimerians from Galliformes. The discovery of a potentially pathogenic species of Eimeria in captive APCs is of great importance, and managers should be aware of the potential devastating effect(s) this parasite could have on the APC conservation programs. PMID:21506827

Fritzler, Jason M; Craig, Thomas M; Elgayar, Amal; Plummer, Casey; Wilson, R Steve; Peterson, Markus J; Zhu, Guan

2011-08-01

327

Cryptosporidium scrofarum n. sp. (Apicomplexa: Cryptosporidiidae) in domestic pigs (Sus scrofa)  

PubMed Central

We describe the morphological, biological, and molecular characteristics of Cryptosporidium pig genotype II and propose the species name Cryptosporidium scrofarum n. sp. to reflect its prevalence in adult pigs worldwide. Oocysts of C. scrofarum are morphologically indistinguishable from C. parvum, measuring 4.81–5.96 µm (mean = 5.16) × 4.23–5.29 µm (mean = 4.83) with a length to width ratio of 1.07 ± 0.06 (n = 400). Oocysts of C. scrofarum obtained from a naturally infected pig were infectious for 8-week-old pigs but not 4-week-old pigs. The prepatent period in 8-week-old Cryptosporidium-naive pigs was 4–6 days and the patent period was longer than 30 days. The infection intensity of C. scrofarum in pigs was generally low, in the range 250-4000 oocysts per gram of faeces. Infected pigs showed no clinical signs of cryptosporidiosis and no pathology was detected. Cryptosporidium scrofarum was not infectious for adult SCID mice, adult BALB c mice, Mongolian gerbils (Meriones unguiculatus), southern multimammate mice (Mastomys coucha), yellow-necked mice (Apodemus flavicollis), or guinea pigs (Cavia porcellus). Phylogenetic analyses based on Small subunit rRNA, actin, and heat shock protein 70 gene sequences revealed that C. scrofarum is genetically distinct from all known Cryptosporidium species. PMID:23021264

Kvá?, Martin; Kest?ánová, Michaela; Pinková, Martina; Kv?to?ová, Dana; Kalinová, Jana; Wagnerová, Pavla; Kotková, Michaela; Vítovec, Ji?í; Ditrich, Oleg; McEvoy, John; Stenger, Brianna; Sak, Bohumil

2012-01-01

328

Life cycle of Cystoisospora felis (Coccidia: Apicomplexa) in cats and mice.  

PubMed

Cystoisospora felis is a ubiquitous apicomplexan protozoon of cats. The endogenous development of C. felis was studied in cats after feeding them infected mice. For this, five newborn cats were killed at 24, 48, 72, 96, and 120 h after having been fed mesenteric lymph nodes and spleens of mice that were inoculated with C. felis sporulated sporocysts. Asexual and sexual development occurred in enterocytes throughout the villi of the small intestine. The number of asexual generations was not determined with certainty, but there were different sized merozoites. At 24 h, merogony was seen only in the duodenum and the jejunum. Beginning at 48 h, the entire small intestine was parasitized. At 24 h, meronts contained 1-4 zoites, and at 48 h up to 12 zoites. Beginning with 72 h, the ileum was more heavily parasitized than the jejunum. At 96 and 120 h, meronts contained many zoites in various stages of development; some divided by endodyogeny. The multiplication was asynchronous, thus both immature multinucleated meronts and mature merozoites were seen in the same parasitophorous vacuole. Gametogony occurred between 96 and 120 h, and oocysts were present at 120 h. For the study of the development of C. felis in murine tissues, mice were killed from day 1 to 720 d after having been fed 10(5) sporocysts, and their tissues were examined for the parasites microscopically, and by bioassay in cats. The following conclusions were drawn. (1) Cystoisospora felis most frequently invaded the mesenteric lymph nodes of mice and remained there for at least 23 mo. (2) It also invaded the spleen, liver, brain, lung, and skeletal muscle of mice, but division was not seen based on microscopical examination. (3) This species could not be passed from mouse to mouse. PMID:25041145

Dubey, J P

2014-01-01

329

CALYPTOSPORA FUNDULI (APICOMPLEXA, CALYPTOSPORIDAE IN THE LIVER OF THE GULF TOADFISH, OPSANUS BETA  

EPA Science Inventory

Authors report the occurrence of what appears to be C. funduli nfecting the liver of a single specimen of gulf toadfish, opsanus eta, from a total of 54 toadfish livers examined histologically. oadfish were captured by trawling from aters of the Mississippi ound near ocean Spring...

330

Seasonality, prevalence and pathogenicity of the gregarine Ascogregarina taiwanensis (Apicomplexa: Lecudinidae) in mosquitoes from Florida.  

PubMed

Aedes albopictus larvae collected in Gainesville, FL, were infected with the gregarine Ascogregarina taiwanensis. Natural prevalence varied from 68 to 100%. Eight mosquito species were tested in the laboratory for susceptibility to A. taiwanensis isolated from field-collected Ae. albopictus. Aedes aegypti, Aedes albopictus, and Aedes taeniorhynchus became 100% infected in the larval stage, whereas Aedes triseriatus was less susceptible; Culex quinquefasciatus, Culex nigripalpus, Culex territans, and Anopheles quadrimaculatus were not susceptible. Viable A. taiwanensis oocysts from adults were recovered from Ae. taeniorhynchus (30%) and Ae. albopictus (100%); no oocysts were produced in the other exposed hosts. Mortality induced by A. taiwanensis infection was low in all mosquitoes except Ae. taeniorhynchus. We conclude that A. taiwanensis has little short-term impact on the mortality of the 3 most common container-inhabiting mosquito species in Florida; however, the long-term impact on overall host population regulation has yet to be determined. PMID:7807086

Garcia, J J; Fukuda, T; Becnel, J J

1994-09-01

331

Development of Eimeria nieschulzi (Coccidia, Apicomplexa) Gamonts and Oocysts in Primary Fetal Rat Cells  

PubMed Central

The in vitro production of gametocytes and oocysts of the apicomplexan parasite genus Eimeria is still a challenge in coccidiosis research. Until today, an in vitro development of gametocytes or oocysts had only been shown in some Eimeria species. For several mammalian Eimeria species, partial developments could be achieved in different cell types, but a development up to gametocytes or oocysts is still lacking. This study compares several permanent cell lines with primary fetal cells of the black rat (Rattus norvegicus) concerning the qualitative in vitro development of the rat parasite Eimeria nieschulzi. With the help of transgenic parasites, the developmental progress was documented. The selected Eimeria nieschulzi strain constitutively expresses the yellow fluorescent protein and a macrogamont specific upregulated red tandem dimer tomato. In the majority of all investigated host cells the development stopped at the second merozoite stage. In a mixed culture of cells derived from inner fetal organs the development of schizont generations I-IV, macrogamonts, and oocysts were observed in crypt-like organoid structures. Microgamonts and microgametes could not be observed and oocysts did not sporulate under air supply. By immunohistology, we could confirm that wild-type E. nieschulzi stages can be found in the crypts of the small intestine. The results of this study may be helpful for characterization of native host cells and for development of an in vitro cultivation system for Eimeria species. PMID:23862053

Wiedmer, Stefanie; Entzeroth, Rolf

2013-01-01

332

Sarcocystis cafferi, n. sp. (Protozoa: Apicomplexa) from the African buffalo (Syncerus caffer)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Four species of Sarcocystis are currently recognized in the Asian water buffalo (Bubalus bubalis): Sarcocystis fusiformis with macrocysts and cats as definitive hosts, S. buffalonis also with macrocysts and cats as definitive hosts, S. levinei with microcysts and dogs as definitive hosts, and S. dub...

333

Occurrence of Leucocytozoon and Haemoproteus (Apicomplexa, Haemosporina) in Falconiformes and Strigiformes of Italy.  

PubMed

Blood smears from Falconiformes (91 birds of 10 species) and Strigiformes (23 birds of 5 species) captured in Italy, were examined for haematozoa. Leucocytozoon were found in Falco tinnuculus, Buteo buteo, Circus cyaneus, Circus pygargus, Accipiter nisus from Falconiformes and in Strix aluco, from Strigiformes. Haemoproteus were found in Falco tinnuculus and Strix aluco; this latter species harbored mixed infections Leucocytozoon-Haemoproteus. Prevalences were 20.80% in Falconiformes and 21.74% in Strigiformes. PMID:6431891

Sacchi, L; Prigioni, C

1984-01-01

334

Life cycle of Cystoisospora felis (Coccidia: Apicomplexa) in cats and mice  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cystoisospora felis is a ubiquitous apicomplexan protozoon of cats. The endogenous development of C. felis was studied in cats after feeding them infected mice. For this, 5 newborn cats were killed at 24, 48, 72, 96, and 120 h after having been fed mesenteric lymph nodes and spleens of mice that wer...

335

Molecular phylogeny and surface morphology of marine aseptate gregarines (Apicomplexa): Selenidium spp. and Lecudina spp.  

PubMed

Many aseptate gregarines from marine invertebrate hosts are thought to have retained several plesiomorphic characteristics and are instrumental in understanding the early evolution of intracellular parasitism in apicomplexans and the phylogenetic position of cryptosporidians. We sequenced the small-subunit (SSU) ribosomal RNA genes from 2 archigregarines, Selenidium terebellae and Selenidium vivax, and 2 morphotypes of the marine eugregarine Lecudina polymorpha. We also used scanning electron microscopy to investigate the surface morphology of trophozoites from Lecudina tuzetae, Monocystis agilis, the 2 species of Selenidium, and the 2 morphotypes of L. polymorpha. The SSU ribosomal DNA sequences from S. vivax and L. polymorpha had long branch lengths characteristic of other gregarine sequences. However, the sequence from S. terebellae was not exceptionally divergent and consistently emerged as 1 of the earliest 'true' gregarines in phylogenetic analyses. Statistical support for the sister relationship between Cryptosporidium spp. and gregarines was significantly bolstered in analyses including the sequence from S. terebellae but excluding the longest branches in the alignment. Eugregarines formed a monophyletic group with the neogregarine Ophryocystis, suggesting that trophozoites with elaborate cortex folds and gliding motility evolved only once. The trophozoites from the 2 species of Selenidium shared novel transverse striations but differed from one another in overall cell morphologies and writhing behavior. PMID:14740910

Leander, B S; Harper, J T; Keeling, P J

2003-12-01

336

Eimeria sinaitae n. sp. (Apicomplexa: Eimeriidae) from the rock agama (Agama sinaita) in Saudi Arabia.  

PubMed

Eimeria sinaitae n. sp. is described from the gall bladder of Agama sinaita from Wasie, Saudi Arabia. Sporulated oocysts are elongate-ellipsoid 34.4 x 22.0 (29.0-40.0 x 17.4-24.5) micron. Oocyst wall is smooth, greenish yellow, 1.2 (1.0-1.4) micron thick, and two-layered. Micropyle, polar granule, and oocyst residuum are absent. Sporocysts are ellipsoid 11.4 x 7.6 (9.8-15.0 x 6.7-9.0) micron. Sporocyst residuum is present. The sporocysts lack a Stieda body. Sporozoites are crescent-shaped, blunt at one end and tapered at the other. Eimeria species from Agamidae are compared. PMID:3183998

Kasim, A A; al Shawa, Y R

1988-08-01

337

Caryospora biarmicusis sp.n. (Apicomplexa: Eimeriidae) infecting falcons from the genus Falco in Saudi Arabia.  

PubMed

The oocysts of Caryospora biarmicusis sp.n. is described from the feces of the lanner falcon, Falco biarmicus, from the falcon market in Riyadh City, Saudi Arabia. Sporulated oocysts are ovoid in shape, measuring 40.2 x 34.7 (37.5-42.4 x 32.9-35.7) microm; shape index (L/W) is 1.16 (1.08-1.31) microm. The oocyst wall is smooth and bi-layered. Micropyle and polar granule are absent, but an oocyst residuum is present. Sporocysts are spheroid, 20.1 (18.6-21.3) microm; with a smooth single-layered wall, lacking Stieda body. Sporocyst residuum is present as numerous small granules. Sporozoites are stout with a large single refractile body. PMID:21634236

Alyousif, M S; Alfaleh, F A; Al-Shawa, Y R

2011-04-01

338

Eimeria biarmicus sp.n. (Apicomplexa: Eimeriidae) infecting falcons from the genus Falco in Saudi Arabia.  

PubMed

The oocysts of Eimeria biarmicus sp. n. were described from the feces of the lanner falcon, Falco biarmicus, collected from the falcon market in Riyadh City, Saudi Arabia. The prevalence of infection was 5% (2/40). The majority of the oocysts examined had completed sporulation within 84 h at 24 ± 2°C. Sporulated oocysts are ovoid in shape, measuring 22.4 × 17.9 (20.5-24.7 × 15.8-18.5) ?m; shape index (L/W) is 1.25 (1.14-1.36) ?m. The oocyst wall is smooth and bi-layered. Micropyle and oocyst residuum are absent. A polar granule is present, consisting of 2-4 globules. Sporocysts are ovoid, 10.1 × 6.1 (9.4-11.2 × 5.4-6.8) ?m; with a smooth single-layered wall and a minute Stieda body, but there is no substieda body. The sporocyst residuum consists of numerous small granules. Sporozoites are comma shaped, each contains two refractile bodies. E. biarmicus sp. n. is the second eimerian species described from F. biarmicus. PMID:21997853

Alfaleh, F A; Alyousif, M S; Al-Quraishy, S; Al-Shawa, Y R

2012-05-01

339

Species of Eimeria (Apicomplexa: Eimeriidae) from bats (Chiroptera: Vespertilionidae) in central Wyoming.  

PubMed

Feces from 60 bats representing 5 species and 4 genera collected in central Wyoming in 2001 were examined for the presence of coccidia. Two species of Eimeria were identified in 4 bats representing 2 species of Myotis. All infected animals harbored a single species; there was no multispecies infection. Eimeria catronensis was recovered from 3 little brown bats (Myotis lucifugus), and Eimeria californicensis was identified from a single long-legged myotis (Myotis volans). Both represent new geographic records and the second a new host record. Eimeria catronensis-like oocysts were recovered from a single silver-haired bat (Lasionycteris noctivagans). Descriptions and taxonomic summaries for the eimerian species are presented in this study. PMID:15165058

Seville, Robert S; Gruver, Jeffrey

2004-04-01

340

Descriptions of six new species of Caryospora (Apicomplexa: Eimeriidae) from Guatemalan snakes (Serpentes: Colubridae and Viperidae).  

PubMed

One hundred and seventy snakes were collected in Guatemala and examined for coccidia. Of these, 8 individuals representing 6 host species were positive for Caryospora spp., 6 of which are described as new species. Sporulated oocysts of Caryospora bothriechis n. sp. from Bothriechis aurifer are spheroidal to subspheroidal, 12.7 x 12.5 (12-14 x 12-13) microm, with a length/width (L/W) ratio of 1.0; they lack a micropyle (M) or oocyst residuum (OR), but 1 large polar granule (PG) is usually present. Sporocysts are ovoidal, 9.0-7.5 (8-10 x 7-8) microm, and have a L/W ratio of 1.2, and a Stieda body (SB) and sporocyst residuum (SR). Oocysts of Caryospora coniophanis n. sp. from Coniophanes imperialis are spheroidal to subspheroidal, 18.8 x 18.1 (17-20.5 x 16-20) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 13.2 x 9.4 (12-15 x 8-10) microm with a L/W ratio of 1.4, and a SB, substieda body (SSB), and SR. Oocysts of Caryospora conophae n. sp. from Conophis lineatus are spheroid to subspheroidal, 20.4 x 19.5 (17-26 x 17-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 13.1 x 9.8 (11-15 x 8-11) microm with a L/W ratio of 1.3 and a SB, SSB, and SR. Oocysts of Caryospora guatemalensis n. sp. from Lampropeltis triangulum are spheroidal to subspheroidal, 23.9 x 23.2 (20-27 x 20-26) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 14.4 x 10.6 (13-18 x 9-13) microm, with a L/W ratio of 1.4 and a SB, SSB, and SR. Oocysts of Caryospora mayorum n. sp. from Conophis lineatus are spheroidal to subspheroidal, 25.6 x 24.4 (24-27 x 24-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 16.3 x 11.9 (16-18 x 11-13) microm, with a L/W ratio of 1.4 and a SB, SSB, and SR. Oocysts of Caryospora zacapensis n. sp. from Masticophis mentovarius are spheroidal to subspheroidal, 22.5 x 21.8 (19-25 x 18-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 14.6 x 11.4 (11-16 x 10-13) microm, with a L/W ratio of 1.3 and a SB, SSB, and SR. PMID:16539030

Seville, Robert S; Asmundsson, Ingrid M; Campbell, Jonathan A

2005-12-01

341

The development of Psychodiella sergenti (Apicomplexa: Eugregarinorida) in Phlebotomus sergenti (Diptera: Psychodidae)  

PubMed Central

SUMMARY Psychodiella sergenti is a recently described specific pathogen of the sand fly Phlebotomus sergenti, the main vector of Leishmania tropica. The aim of this study was to examine the life cycle of Ps. sergenti in various developmental stages of the sand fly host. The microscopical methods used include scanning electron microscopy, transmission electron microscopy and light microscopy of native preparations and histological sections stained with periodic acid-Schiff reaction. Psychodiella sergenti oocysts were observed on the chorion of sand fly eggs. In 1st instar larvae, sporozoites were located in the ectoperitrophic space of the intestine. No intracellular stages were found. In 4th instar larvae, Ps. sergenti was mostly located in the ectoperitrophic space of the intestine of the larvae before defecation and in the intestinal lumen of the larvae after defecation. In adults, the parasite was recorded in the body cavity, where the sexual development was triggered by a bloodmeal intake. Psychodiella sergenti has several unique features. It develops sexually exclusively in sand fly females that took a bloodmeal, and its sporozoites bear a distinctive conoid (about 700 nm long), which is more than 4 times longer than conoids of the mosquito gregarines. PMID:22313575

LANTOVA, LUCIE; VOLF, PETR

2012-01-01

342

Sarcocystis cafferi n. sp. (Protozoa: Apicomplexa) from the African Buffalo (Syncerus caffer).  

PubMed

Abstract :? Sarcocystis infections have been reported from the African buffalo ( Syncerus caffer ), but the species have not been named. Here we propose a new name Sarcocystis cafferi from the African buffalo. Histological examination of heart (92), skeletal muscle (36), and tongue (2) sections from 94 buffalos from the Greater Kruger National Park, South Africa, and a review of the literature revealed only 1 species of Sarcocystis in the African buffalo. Macrocysts were up to 12 mm long and 6 mm wide and were located in the neck muscles and overlying connective tissue. They were pale yellow; shaped like a lychee fruit stone or cashew nut; turgid or flaccid and oval to round (not fusiform). By light microscopy (LM) the sarcocyst wall was relatively thin. By scanning electron microscopy (SEM), the sarcocyst wall had a mesh-like structure with irregularly shaped villar protrusions (vp) that were of different sizes and folded over the sarcocyst wall. The entire surfaces of vp were covered with papillomatous structures. By transmission electron microscopy (TEM), the sarcocyst wall was up to 3.6 ?m thick and had highly branched villar protrusions that were up to 3 ?m long. The villar projections contained filamentous tubular structures, most of which were parallel to the long axis of the projections, but some tubules criss-crossed, especially at the base. Granules were absent from these tubules. Longitudinally cut bradyzoites were 12.1 × 2.7 ?m in size, had a long convoluted mitochondrion, and only 2 rhoptries. Phylogenetic analysis of 18S rRNA and cytochrome C oxidase subunit 1 (cox1) gene sequences indicated that this Sarcocystis species is very closely related to, but distinct from, Sarcocystis fusiformis and Sarcocystis hirsuta. Thus, morphological findings by LM, SEM, and TEM together with molecular phylogenetic data (from 18S rRNA and cox1) confirm that the Sarcocystis species in the African buffalo is distinct from S. fusiformis and has therefore been named Sarcocystis cafferi. PMID:25026178

Dubey, J P; Lane, Emily P; van Wilpe, Erna; Suleman, Essa; Reininghaus, Bjorn; Verma, S K; Rosenthal, B M; Mtshali, Moses S

2014-12-01

343

Caryospora uptoni n. sp. (Apicomplexa: Eimeriidae) from red-tailed hawks (Buteo jamaicensis borealis).  

PubMed

Oocysts of Caryospora uptoni n. sp. were described from the feces of red-tailed hawks, Buteo jamaicensis borealis. Sporulated oocysts were spherical or subspherical and measured 28.1 by 26.4 micron. The oocyst wall was composed of a yellowish outer layer and brownish inner layer and was about 1.5 micron thick. Neither micropyle, polar granules, nor oocyst residuum were present. A single, spherical sporocyst 18.2 by 17.9 micron was present; a Stieda body was absent. A spherical eccentrically located sporocyst residuum was present in many sporocysts, but it degenerated to form a dispersed granular residuum in other sporocysts. Eight randomly arranged sporozoites, 12.6 by 4.2 micron, were present in each sporocyst; they contained a centrally or slightly posteriorly located nucleus. PMID:3806324

Lindsay, D S; Blagburn, B L

1986-10-01

344

Haemogregarine parasites (Apicomplexa: Hepatozoidae) in Caiman crocodilus yacare (Crocodilia: Alligatoridae) from Pantanal, Corumbá, MS, Brazil.  

PubMed

Haemogregarines were recorded in caimans Caiman crocodilus yacare from Pantanal. This study was carried out in seasonal ponds at the Miranda- Abobral subregion of Pantanal, State of Mato Grosso do Sul, western Brazil, from 1998 to 1999. Smears from 28 caimans were examined and 20 (71.4%) presented infection by a haemogregarine. Infections were observed in 11 males and 9 females. Morphological and morphometric observations suggest that the parasite forms found in this work are Hepatozoon caimani. PMID:16445875

Viana, Lúcio A; Marques, Eliézer J

2005-01-01

345

Three new Hepatozoon species (Apicomplexa: Hepatozoidae) infecting the Florida kingsnake, Lampropeltis getula floridana.  

PubMed

The Florida kingsnake, Lampropeltis getula floridana, is host to 3 species of Hepatozoon at the type locality, Miramar, Broward County, Florida, and 2, possibly all 3, species at Cedar Key, Levy County, approximately 480 km to the northwest. Hepatozoon eurytopis, n. sp. was present also in Diadophis punctatus and Elaphe guttata in Jupiter Farms, Palm Beach County, and in Thamnophis sirtalis at Gainesville, Alachua County. Specific identity in D. punctatus was determined from gamont morphology and from sporogonic stages and gamont morphology in the infections obtained from E. guttata and T. sirtalis. Infection with all 3 species by ingestion of infected mosquitoes was easily obtained in E. guttata, but only H. eurytopis produced experimental infection in T. sirtalis and Storeria occipitomaculata. Hepatozoon eurytopis differed from the other 2 species, H. karyolysi n. sp. and H. rexi n. sp., by its short and broad, recurved gamonts with average dimensions 11.2-13.1 x 4.5-5.4 microm, length x maximum width (LW) 56-64 microm(2), and L/W ratios 2.13-2.80 in all host species, large round oocysts 95-303 x 91-285 microm, L/W ratios 1.03-1.05 with spherical to ovoid sporocysts 22-50 x 21-44 microm, L/W ratios 1.00-1.82 that contain 33.5-44.4 (16-76) sporozoites. The nucleus in immature gamonts is highly irregular, often fragmented in separate masses of chromatin, and commonly appears to form binucleate gamonts before maturity. Hepatozoon karyolysi has elongate, non-recurved gamonts, 15-20 x 4-7 microm, LW 64-143 microm(2), L/W ratios 2.3-4.5 that usually cause lysis or irregular margins of the nucleus in infected erythrocytes of the type host. Oocysts are spherical, 127-243 x 122-233 microm, L/W ratio 1.0-1.1 that contain spherical to usually ovoid sporocysts 17-30 x 17-24 microm, and produce 12-20 sporozoites. Gamonts of Hepatozoon rexi are non-recurved, 14-18 x 4-6 microm, LW 67-102 microm(2), and L/W ratio 2.8-4.1, and are usually surrounded by a prominent cyst wall within the host erythrocyte. Oocysts are nearly spherical, 103-178 x 103-172 microm, form usually elongate sporocysts, 30-39 x 20-25 microm L/W ratio 1.33-1.94 that contain 16-36 sporozoites. An oocyst of H. eurytopis was present in the salivary gland of an infected Aedes aegypti , which is the second report of sporogony by a Hepatozoon species occurring in this site. PMID:19685939

Telford, Sam R

2010-02-01

346

Novel type of linear mitochondrial genomes with dual flip-flop inversion system in apicomplexan parasites, Babesia microti and Babesia rodhaini  

PubMed Central

Background Mitochondrial (mt) genomes vary considerably in size, structure and gene content. The mt genomes of the phylum Apicomplexa, which includes important human pathogens such as the malaria parasite Plasmodium, also show marked diversity of structure. Plasmodium has a concatenated linear mt genome of the smallest size (6-kb); Babesia and Theileria have a linear monomeric mt genome (6.5-kb to 8.2-kb) with terminal inverted repeats; Eimeria, which is distantly related to Plasmodium and Babesia/Theileria, possesses a mt genome (6.2-kb) with a concatemeric form similar to that of Plasmodium; Cryptosporidium, the earliest branching lineage within the phylum Apicomplexa, has no mt genome. We are interested in the evolutionary origin of linear mt genomes of Babesia/Theileria, and have investigated mt genome structures in members of archaeopiroplasmid, a lineage branched off earlier from Babesia/Theileria. Results The complete mt genomes of archaeopiroplasmid parasites, Babesia microti and Babesia rodhaini, were sequenced. The mt genomes of B. microti (11.1-kb) and B. rodhaini (6.9-kb) possess two pairs of unique inverted repeats, IR-A and IR-B. Flip-flop inversions between two IR-As and between two IR-Bs appear to generate four distinct genome structures that are present at an equi-molar ratio. An individual parasite contained multiple mt genome structures, with 20 copies and 2 – 3 copies per haploid nuclear genome in B. microti and B. rodhaini, respectively. Conclusion We found a novel linear monomeric mt genome structure of B. microti and B. rhodhaini equipped with dual flip-flop inversion system, by which four distinct genome structures are readily generated. To our knowledge, this study is the first to report the presence of two pairs of distinct IR sequences within a monomeric linear mt genome. The present finding provides insight into further understanding of evolution of mt genome structure. PMID:23151128

2012-01-01

347

A Survey of Innovation through Duplication in the Reduced Genomes of Twelve Parasites  

PubMed Central

We characterize the prevalence, distribution, divergence, and putative functions of detectable two-copy paralogs and segmental duplications in the Apicomplexa, a phylum of parasitic protists. Apicomplexans are mostly obligate intracellular parasites responsible for human and animal diseases (e.g. malaria and toxoplasmosis). Gene loss is a major force in the phylum. Genomes are small and protein-encoding gene repertoires are reduced. Despite this genomic streamlining, duplications and gene family amplifications are present. The potential for innovation introduced by duplications is of particular interest. We compared genomes of twelve apicomplexans across four lineages and used orthology and genome cartography to map distributions of duplications against genome architectures. Segmental duplications appear limited to five species. Where present, they correspond to regions enriched for multi-copy and species-specific genes, pointing toward roles in adaptation and innovation. We found a phylum-wide association of duplications with dynamic chromosome regions and syntenic breakpoints. Trends in the distribution of duplicated genes indicate that recent, species-specific duplicates are often tandem while most others have been dispersed by genome rearrangements. These trends show a relationship between genome architecture and gene duplication. Functional analysis reveals: proteases, which are vital to a parasitic lifecycle, to be prominent in putative recent duplications; a pair of paralogous genes in Toxoplasma gondii previously shown to produce the rate-limiting step in dopamine synthesis in mammalian cells, a possible link to the modification of host behavior; and phylum-wide differences in expression and subcellular localization, indicative of modes of divergence. We have uncovered trends in multiple modes of duplicate divergence including sequence, intron content, expression, subcellular localization, and functions of putative recent duplicates that highlight the role of duplications in the continuum of forces that have shaped these genomes. PMID:24919110

DeBarry, Jeremy D.; Kissinger, Jessica C.

2014-01-01

348

A survey of innovation through duplication in the reduced genomes of twelve parasites.  

PubMed

We characterize the prevalence, distribution, divergence, and putative functions of detectable two-copy paralogs and segmental duplications in the Apicomplexa, a phylum of parasitic protists. Apicomplexans are mostly obligate intracellular parasites responsible for human and animal diseases (e.g. malaria and toxoplasmosis). Gene loss is a major force in the phylum. Genomes are small and protein-encoding gene repertoires are reduced. Despite this genomic streamlining, duplications and gene family amplifications are present. The potential for innovation introduced by duplications is of particular interest. We compared genomes of twelve apicomplexans across four lineages and used orthology and genome cartography to map distributions of duplications against genome architectures. Segmental duplications appear limited to five species. Where present, they correspond to regions enriched for multi-copy and species-specific genes, pointing toward roles in adaptation and innovation. We found a phylum-wide association of duplications with dynamic chromosome regions and syntenic breakpoints. Trends in the distribution of duplicated genes indicate that recent, species-specific duplicates are often tandem while most others have been dispersed by genome rearrangements. These trends show a relationship between genome architecture and gene duplication. Functional analysis reveals: proteases, which are vital to a parasitic lifecycle, to be prominent in putative recent duplications; a pair of paralogous genes in Toxoplasma gondii previously shown to produce the rate-limiting step in dopamine synthesis in mammalian cells, a possible link to the modification of host behavior; and phylum-wide differences in expression and subcellular localization, indicative of modes of divergence. We have uncovered trends in multiple modes of duplicate divergence including sequence, intron content, expression, subcellular localization, and functions of putative recent duplicates that highlight the role of duplications in the continuum of forces that have shaped these genomes. PMID:24919110

DeBarry, Jeremy D; Kissinger, Jessica C

2014-01-01

349

Phylogeny of Arenig to Caradoc crinoids (Phylum Echinodermata) and suprageneric classification of the Crinoidea  

E-print Network

features of the arms, calyx, and column. Thus, 21 characters were used for cladids and the flexible; 27 Aethocrinea Cladida ,tinerata Disparida Caryocystites Aethocrinus Perittocrinus Tetracionocrinus Brechmocrinus Elpasocrinus Palaeocrinus Archaetaxocrinus... (16 genera). The analysis included 18 characters (Appendix B, p. 34; basal concavity, arm number, and arm habit are constant) with a total of 54 character states. The 50-percent majority-rule tree is from 13 equally parsimonious trees of length 56...

Ausich, W. I.

1998-06-01

350

Cell number and cellular composition in infusoriform larvae of dicyemid mesozoans (Phylum Dicyemida).  

PubMed

Cell numbers and cellular composition were examined in infusoriform larvae of 44 species of dicyemid mesozoans belonging to 6 genera; Conocyema, Dicyema, Dicyemennea, Dicyemodeca, Microcyema, and Pseudicyema. In addition, literature on infusoriform larvae of another 20 species was reviewed. Infusoriform larvae consist of a constant cell number which is species-specific. Small interspecific variations are found in total cell numbers, 35, 37, 39, 41 and 42. The most frequent cell number encountered in infusoriform larvae studied is either 37 or 39. Infusoriform larvae with 35 cells are found in three genera. Infusoriform larvae with 37 cells are found in four genera. Infusoriform larvae with 39 cells are found in four genera. Most differences in total cell numbers are due to the absence or presence of particular ventral cells. In all infusoriform larvae, the lateral, dorsal and caudal areas are cell constant, whereas in the apical and ventral areas a distinct and variable configuration of cells are present. In cellular composition, a total of 29 cells (15 cell types) were recognized in all infusoriform larvae examined. Additional cell types are characteristic of a relatively few species. Even in infusoriform larvae with the same total cell numbers, cellular composition varies by species. Thus, there are 7 variations of cellular composition in infusoriform larvae with 37 cells. Differences in larval cell numbers and types do not warrant traditional generic separation of dicyemids. PMID:15334001

Furuya, Hidetaka; Hochberg, F G; Tsuneki, Kazuhiko

2004-08-01

351

Cloning of chitinase-like protein1 cDNA from dicyemid mesozoans (Phylum: Dicyemida).  

PubMed

Dicyemid mesozoans are endoparasites found in the renal sacs of benthic cephalopods. Adult dicyemids insert the distinct anterior region, termed a "calotte," into renal tubules of the host. We cloned cDNA encoding chitinase-like protein from the dicyemid Dicyema japonicum (Dicyema-clp 1), and also cloned the gene fragment corresponding to the cDNA. Dicyema-clp1 has the hydrophobic amino acid-rich region, but not the chitin-binding domains at the C terminus. Analyses using the SignalP prediction program suggest this hydrophobic amino acid-rich region is the anchor sequence to plasma membranes. The putative catalytic site in glyco18 domain exhibited 1 substitution from aspartic acid to asparagine. The gene fragment had short 9 introns (22-26 bp), and the coding sequence consisted of 10 exons (30-233 bp). Specific and strong expression of Dicyema-clpl was detected in the calotte of vermiform stages by whole mount in situ hybridization. N-acetyl-D-glucosamine was detected on the outer surface of both peripheral cells of dicyemids and epidermal cells of host renal appendages. Dicyema-clp appears to be associated with N-acetyl-D-glucosamine in the interface between dicyemid peripheral cells and epidermal cells of the host renal appendage, and possibly aids in adhering the calotte to host epidermal cells. PMID:18314687

Ogino, Kazutoyo; Tsuneki, Kazuhiko; Furuya, Hidetaka

2007-12-01

352

Peanut worms of the phylum Sipuncula from the Sea of Japan with a key to species  

NASA Astrophysics Data System (ADS)

Sipunculan worms from the Russian waters of the Sea of Japan are still poorly investigated while they are much better known from the Japanese coast. The aim of this paper is to describe sipunculans from the Russian coast and from the deepest part of the Sea of Japan near the Primorye Province collected by SoJaBio expedition, and to provide keys for identification of sipunculan species from the Sea of Japan. At the Russian coast of the Sea of Japan only 8 valid species of sipunculans were found and identified: Golfingia margaritacea, G. vulgaris, Nephasoma capilleforme, N. wodjanizkii, Phascolion strombus, Thysanocardia nigra, Themiste hexadactyla (=T. pyroides), Phascolosoma agassizii. Taking into account 4 other valid species noted for this area, Nephasoma eremite, Thysanocardia catharinae, Themiste blanda and Phascolosoma scolops, which were not found, the sipunculan fauna of the Russian waters of the Sea of Japan now comprises 12 valid species. Nephasoma capilleforme and Nephasoma wodjanizkii are the first records for the North-West Pacific and the Sea of Japan. Species accounts include the most important taxonomic characters and specific biotope data. Accordingly, a key up to species level is provided. Totally, the fauna of the Sea of Japan is now estimated as having 31 valid species of sipunculans.

Maiorova, Anastassya S.; Adrianov, Andrey V.

2013-02-01

353

First Sequenced Mitochondrial Genome from the Phylum Acanthocephala( Leptorhynchoides thecatus ) and Its Phylogenetic Position Within Metazoa  

Microsoft Academic Search

The complete sequence of the mitochondrial genome of Leptorhynchoides thecatus (Acanthocephala) was determined, and a phylogenetic analysis was carried out to determine its placement within Metazoa. The genome is circular, 13,888 bp, and contains at least 36 of the 37 genes typically found in animal mitochondrial genomes. The genes for the large and small ribosomal RNA subunits are shorter than

Michelle L. Steinauer; Brent B. Nickol; Richard Broughton; Guillermo Ortí

2005-01-01

354

Depth Distribution for the Order Cydippid (Phylum Ctenophora, Class Tentaculata) in the Monterey Submarine Canyon  

Microsoft Academic Search

This paper will discuss depth distribution analysis of cydippids in the Monterey Bay Submarine Canyon. Cydippids in the Monterey Canyon have been sighted at many different depths and areas. Since 1989, ten different cydippid species, including two new cydippids this year, were recorded on video using a remotely operated vehicle in ten sites within the Monterey Canyon. Because most of

Laura Dippold; Judith Connor; Nancy Jacobsen

355

Draft Genome Sequence of Enterobacter sp. Strain UCD-UG_FMILLET (Phylum Proteobacteria).  

PubMed

Here, we present the draft genome of Enterobacter sp. strain UCD-UG_FMILLET. This strain is an endophyte isolated from the roots of finger millet, an Afro-Indian cereal crop. The genome contains 4,801,411 bp in 53 scaffolds. PMID:25614569

Ettinger, Cassandra L; Mousa, Walaa M; Raizada, Manish N; Eisen, Jonathan A

2015-01-01

356

Correction: Phylogenetic placement of the enigmatic parasite, Polypodium hydriforme, within the Phylum Cnidaria  

E-print Network

of Sciences, St. Petersburg, Russia and 4National Systematics Laboratory of NOAA Fisheries Service, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA Email: Nathaniel M Evans - evansnat@ku.edu; Alberto Lindner...

Evans, Nathaniel M.; Lindner, Alberto; Raikova, Ekaterina V.; Collins, Allen G.; Cartwright, Paulyn

2009-07-15

357

Draft Genome Sequence of Curtobacterium flaccumfaciens Strain UCD-AKU (Phylum Actinobacteria).  

PubMed

Here we present the draft genome of an actinobacterium, Curtobacterium flaccumfaciens strain UCD-AKU, isolated from a residential carpet. The genome assembly contains 3,692,614 bp in 130 contigs. This is the first member of the Curtobacterium genus to be sequenced. PMID:23682147

Flanagan, Jennifer C; Lang, Jenna M; Darling, Aaron E; Eisen, Jonathan A; Coil, David A

2013-01-01

358

Draft Genome Sequence of Curtobacterium flaccumfaciens Strain UCD-AKU (Phylum Actinobacteria)  

PubMed Central

Here we present the draft genome of an actinobacterium, Curtobacterium flaccumfaciens strain UCD-AKU, isolated from a residential carpet. The genome assembly contains 3,692,614 bp in 130 contigs. This is the first member of the Curtobacterium genus to be sequenced. PMID:23682147

Flanagan, Jennifer C.; Lang, Jenna M.; Darling, Aaron E.; Coil, David A.

2013-01-01

359

Horsehair Worms (Phylum Nematomorpha) in Wisconsin, With Notes on Their Occurrence in the Great Lakes  

Microsoft Academic Search

Wisconsin records for Chordodes morgani, Gordius robustus, and Paragordius varius are summarized. The occurrence of horsehair worms in the Great Lakes Is reviewed. Sexual size differences are demonstrated In G. robustus, with females being significantly longer than males. Skewing of sex ratios in horsehair worm populations is discussed.

Dreux J. Watermolen; Ginny L. Haen

1994-01-01

360

Notes on the Distribution and Biology of the Horsehair Worm Paragordius varius (Phylum Nematomorpha) in Wisconsin  

Microsoft Academic Search

Female Paragordius varius were collected in a slough of the Mississippi River in Grant County and a small trout stream in Kewaunee County. The Kewaunee County specimen was laying eggs on July 25, later than reported for the species elsewhere in its range. Paragordius varius is much less common than Gordius robustus in Wisconsin, at least in small cold springs

Philip A. Cochran

1999-01-01

361

Description of seven candidate species affiliated with the phylum Actinobacteria, representing planktonic freshwater bacteria  

PubMed Central

Actinobacteria comprise a substantial fraction of the bacterioplankton in freshwater lakes and streams. Numerous cultivation-independent investigations have retrieved actinobacterial 16S rRNA gene sequences from such habitats. The taxa detected in freshwater habitats are usually absent from terrestrial and marine systems. So far, none of the indigenous freshwater lineages is represented by a taxon with a validly published name. The seven organisms for which Candidatus status is described here were isolated from freshwater lakes and ponds located in tropical, subtropical and temperate climatic zones. Phylogenetic analyses demonstrated that they are affiliated with one of the actinobacterial lineages indigenous to freshwater bacterioplankton. The seven novel taxa could only be cultivated to date as mixed cultures that also contain non-actinobacterial strains. Due to the lack of pure cultures, I propose to establish the candidate species ‘Candidatus Planktoluna difficilis’, ‘Candidatus Aquiluna rubra’, ‘Candidatus Flaviluna lacus’, ‘Candidatus Rhodoluna limnophila’, ‘Candidatus Rhodoluna planktonica’, ‘Candidatus Rhodoluna lacicola’ and ‘Candidatus Limnoluna rubra’ for these taxa. PMID:19126733

Hahn, Martin W.

2014-01-01

362

Intra-phylum and inter-phyla associations among gastrointestinal parasites in two wild mammal species.  

PubMed

A growing body of literature reveals that the interactions among the parasite community may be strong and significant for parasite dynamics. There may be inter-specific antagonistic interactions as a result of competition and cross-effective immune response, or synergistic interactions where infection by one parasite is facilitated by another one, either by an impoverishment of the host's defenses, parasite-induced selective immunosuppression, or trade-offs within the immune system. The nature of these interactions may depend on how related are the parasite species involved. Here we explored the presence of associations among gastrointestinal parasites (coccidia and helminths) in natural populations of two wild mammal species, the capybara (Hydrochoerus hydrochaeris) and the guanaco (Lama guanicoe). The associations explored were between the oocyst outputs of a selected Eimeria species and the other coccidia of that parasite community, and between Eimeria spp. and the predominant nematodes. The statistical analysis included adjustment for potential confounders or effect modifiers. In guanacos, the prevailing interactions were synergistic among the coccidia and between coccidia and nematodes (Nematodirus spp.). However, in capybaras, the interaction between nematodes (Viannaiidae) and Eimeria spp. depended on environmental and host factors. The relationship was positive in some circumstances (depending on season, year, sex, or animal size), but it appeared to become antagonistic under different scenarios. These antagonist interactions did not follow a particular seasonal pattern (they occurred in autumn, spring, and summer), but they were predominantly found in females (when they depended on sex) or in 2010 and 2011 (when they depended on the sampling year). These results suggest that the relationship between coccidia and nematodes in capybaras may be context dependent. We propose that the context-dependent immune investment documented in capybaras may be the cause of these varying interactions. PMID:23820605

Moreno, P G; Eberhardt, M A T; Lamattina, D; Previtali, M A; Beldomenico, P M

2013-09-01

363

Depth Distribution for the Order Cydippid (Phylum Ctenophora, Class Tentaculata) in the Monterey  

E-print Network

This paper will discuss depth distribution analysis of cydippids in the Monterey Bay Submarine Canyon. Cydippids in the Monterey Canyon have been sighted at many different depths and areas. Since 1989, ten different cydippid species, including two new cydippids this year, were recorded on video using a remotely operated vehicle in ten sites within the Monterey Canyon. Because most of the research conducted by the Monterey Bay Aquarium Research Institute has been concentrated in the middle of the bay, cydippids appeared to be most abundant from the Midwater Research Site in the center of the Monterey Canyon, to the Soquel Canyon in the north. For this project, depth was measured in meters. Distribution was divided into approximate depths ranging in 50 meter increments. Two named genera of cydippids, Hormiphora and Pleurobrachia, have similar distribution from 150 to 950 meters. Unknowns #3 and #4 have the same depth distribution, from the deepest depth distribution recorded, 350 to 1050 meters. The orange-cydippid has a depth distribution of

unknown authors

364

Testing the new animal phylogeny: a phylum level molecular analysis of the animal kingdom.  

PubMed

The new animal phylogeny inferred from ribosomal genes some years ago has prompted a number of radical rearrangements of the traditional, morphology based metazoan tree. The two main bilaterian clades, Deuterostomia and Protostomia, find strong support, but the protostomes consist of two sister groups, Ecdysozoa and Lophotrochozoa, not seen in morphology based trees. Although widely accepted, not all recent molecular phylogenetic analyses have supported the tripartite structure of the new animal phylogeny. Furthermore, even if the small ribosomal subunit (SSU) based phylogeny is correct, there is a frustrating lack of resolution of relationships between the phyla that make up the three clades of this tree. To address this issue, we have assembled a dataset including a large number of aligned sequence positions as well as a broad sampling of metazoan phyla. Our dataset consists of sequence data from ribosomal and mitochondrial genes combined with new data from protein coding genes (5139 amino acid and 3524 nucleotide positions in total) from 37 representative taxa sampled across the Metazoa. Our data show strong support for the basic structure of the new animal phylogeny as well as for the Mandibulata including Myriapoda. We also provide some resolution within the Lophotrochozoa, where we confirm support for a monophyletic clade of Echiura, Sipuncula and Annelida and surprising evidence of a close relationship between Brachiopoda and Nemertea. PMID:18692145

Bourlat, Sarah J; Nielsen, Claus; Economou, Andrew D; Telford, Maximilian J

2008-10-01

365

Chryseobacterium takakiae sp. nov., a member of the phylum Bacteroidetes isolated from Takakia lepidozioides.  

PubMed

A Gram-stain-negative, rod-shaped and non-endospore-forming bacterium, designated strain AG1-2(T), was isolated from Takakia lepidozioides collected from the Gawalong glacier in Tibet, China and characterized using a polyphasic taxonomic approach. The predominant fatty acids of strain AG1-2(T) were iso-C15?:?0 (36.0?%), iso-C17?:?0 3-OH (20.2?%), summed feature 9 (iso-C17?:?1?9c and/or C16?:?0 10-methyl, 16.4?%) and summed feature 3 (C16?:?1?7c and/or C16?:?1?6c, 11.1?%). The major polar lipids were phosphatidylethanolamine, three unidentified aminolipids and two unidentified lipids. Strain AG1-2(T) contained MK-6 as the dominant menaquinone, and the genomic DNA G+C content was 37.3 mol%. The phylogenetic analysis based on the 16S rRNA gene sequences showed that strain AG1-2(T) was affiliated to species of the genus Chryseobacterium, and its closest related species were Chryseobacterium taiwanense Soil-3-27(T), Chryseobacterium hispalense AG13(T), Chryseobacterium camelliae THG C4-1(T) and Chryseobacterium taeanense PHA3-4(T) with a sequence similarity of 98.0, 97.8, 97.3 and 97.1?%, respectively. However, the DNA-DNA relatedness values between these strains and strain AG1-2(T) were 29, 21, 21 and 45?%, respectively. Based on phylogenetic inference and phenotypic data, strain AG1-2(T) is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium takakiae sp. nov. is proposed. The type strain is AG1-2(T) (?=?CGMCC 1.12488(T)?=?DSM 26898(T)). PMID:25273512

Zhao, Ran; Chen, Xin Yao; Li, Xue Dong; Chen, Zhi Ling; Li, Yan Hong

2015-01-01

366

Isolation and characterization of a novel chytrid species (phylum Blastocladiomycota), parasitic on the green alga Haematococcus.  

PubMed

A parasite was found in cultures of the green microalga Haematococcus pluvialis that grew epibiotically on algal cells and caused epidemics resulting in damage to the host cultures. The parasite was isolated into axenic culture on solid and liquid media. It was demonstrated to be the sole causative agent of the epidemics. According to its life cycle and phylogenetic analysis based on 18S ribosomal DNA sequences, the pathogen appears to represent a novel chytrid fungus closely related to the vascular plant pathogen Physoderma (Blastocladiomycota), although it differs from all other known chytrids by its infective stage, a wall-less propagule endowed with amoeboid motion and lacking the group's typical flagellum. PMID:18222678

Hoffman, Yoram; Aflalo, Claude; Zarka, Aliza; Gutman, Jenia; James, Timothy Y; Boussiba, Sammy

2008-01-01

367

Form and feeding mechanism of a living Planctosphaera pelagica (phylum Hemichordata)  

Microsoft Academic Search

We describe aspects of the anatomy and suspension-feeding mechanism of a single Planctosphaera pelagica captured from the plankton in June 1992 off Bermuda in the western Atlantic. We also describe several unusual features of the larva, including its occurrence in surface waters, unusually large size, and limited swimming ability. Our account of the form and feeding behavior of P. pelagica

M. W. Hart; R. L. Miller; L. P. Madin

1994-01-01

368

SCO-spondin is evolutionarily conserved in the central nervous system of the chordate phylum  

Microsoft Academic Search

Bovine subcommissural organ-spondin was shown to be a brain-secreted glycoprotein specifically expressed in the subcommissural organ, an ependymal differentiation located in the roof of the Sylvian aqueduct. Also, subcommissural organ-spondin makes part of Reissner's fiber, a phylogenetically and ontogenetically conserved structure present in the central canal of the spinal cord of chordates. This secretion is a large multidomain protein probably

S Gobron; I Creveaux; R Meiniel; R Didier; B Dastugue; A Meiniel

1999-01-01

369

Extensive and evolutionarily persistent mitochondrial tRNA editing in Velvet Worms (phylum Onychophora).  

PubMed

Mitochondrial genomes of onychophorans (velvet worms) present an interesting problem: Some previous studies reported them lacking several transfer RNA (tRNA) genes, whereas others found that all their tRNA genes were present but severely reduced. To resolve this discrepancy, we determined complete mitochondrial DNA (mtDNA) sequences of the onychophorans Oroperipatus sp. and Peripatoides sympatrica as well as cDNA sequences from 14 and 10 of their tRNAs, respectively. We show that tRNA genes in these genomes are indeed highly reduced and encode truncated molecules, which are restored to more conventional structures by extensive tRNA editing. During this editing process, up to 34 nucleotides are added to the tRNA sequences encoded in Oroperipatus sp. mtDNA, rebuilding the aminoacyl acceptor stem, the T?C arm, and in some extreme cases, the variable arm and even a part of the anticodon stem. The editing is less extreme in P. sympatrica in which at least a part of the T?C arm is always encoded in mtDNA. When the entire T?C arm is added de novo in Oroperipatus sp., the sequence of this arm is either identical or similar among different tRNA species, yet the sequences show substantial variation for each tRNA. These observations suggest that the arm is rebuilt, at least in part, by a template-independent mechanism and argue against the alternative possibility that tRNA genes or their parts are imported from the nucleus. By contrast, the 3' end of the aminoacyl acceptor stem is likely restored by a template-dependent mechanism. The extreme tRNA editing reported here has been preserved for >140 My as it was found in both extant families of onychophorans. Furthermore, a similar type of tRNA editing may be present in several other groups of arthropods, which show a high degree of tRNA gene reduction in their mtDNA. PMID:21546355

Segovia, Romulo; Pett, Walker; Trewick, Steve; Lavrov, Dennis V

2011-10-01

370

The mitochondrial genome structure of Xenoturbella bocki (phylum Xenoturbellida) is ancestral within the deuterostomes  

PubMed Central

Background Mitochondrial genome comparisons contribute in multiple ways when inferring animal relationships. As well as primary sequence data, rare genomic changes such as gene order, shared gene boundaries and genetic code changes, which are unlikely to have arisen through convergent evolution, are useful tools in resolving deep phylogenies. Xenoturbella bocki is a morphologically simple benthic marine worm recently found to belong among the deuterostomes. Here we present analyses comparing the Xenoturbella bocki mitochondrial gene order, genetic code and control region to those of other metazoan groups. Results The complete mitochondrial genome sequence of Xenoturbella bocki was determined. The gene order is most similar to that of the chordates and the hemichordates, indicating that this conserved mitochondrial gene order might be ancestral to the deuterostome clade. Using data from all phyla of deuterostomes, we infer the ancestral mitochondrial gene order for this clade. Using inversion and breakpoint analyses of metazoan mitochondrial genomes, we test conflicting hypotheses for the phylogenetic placement of Xenoturbella and find a closer affinity to the hemichordates than to other metazoan groups. Comparative analyses of the control region reveal similarities in the transcription initiation and termination sites and origin of replication of Xenoturbella with those of the vertebrates. Phylogenetic analyses of the mitochondrial sequence indicate a weakly supported placement as a basal deuterostome, a result that may be the effect of compositional bias. Conclusion The mitochondrial genome of Xenoturbella bocki has a very conserved gene arrangement in the deuterostome group, strikingly similar to that of the hemichordates and the chordates, and thus to the ancestral deuterostome gene order. Similarity to the hemichordates in particular is suggested by inversion and breakpoint analysis. Finally, while phylogenetic analyses of the mitochondrial sequences support a basal deuterostome placement, support for this decreases with the use of more sophisticated models of sequence evolution. PMID:19450249

Bourlat, Sarah J; Rota-Stabelli, Omar; Lanfear, Robert; Telford, Maximilian J

2009-01-01

371

Phylum Platyhelminthes Most parasitic platyhelminths belong to one of three classes: Mono-  

E-print Network

are distinguished from sporocysts by the presence of a mouth and digestive system. They are usually motile and can and female reproductive hermaphrodite protogynous protandrous systems. Usually both systems develop simultaneously or the male system develops first (protandrous) but in Gyrodactylid monogenea, the female system

Schluter, Dolph

372

Secretory organelles of pathogenic protozoa.  

PubMed

Secretory processes play an important role on the biology and life cycles of parasitic protozoa. This review focus on basic aspects, from a cell biology perspective, of the secretion of (a) micronemes, rhoptries and dense granules in members of the Apicomplexa group, where these organelles are involved in the process of protozoan penetration into the host cell, survival within the parasitophorous vacuole and subsequent egress from the host cell, (b) the Maurer's cleft in Plasmodium, a structure involved in the secretion of proteins synthesized by the intravacuolar parasite and transported through vesicles to the erythrocyte surface, (c) the secretion of macromolecules into the flagellar pocket of trypanosomatids, and (d) the secretion of proteins which make the cyst wall of Giardia and Entamoeba, with the formation of encystation vesicles. PMID:16710566

Souza, Wanderley de

2006-06-01

373

Molecular survey of parasites in introduced Pelophylax perezi (Ranidae) water frogs in the Azores.  

PubMed

Water frogs, Pelophylax perezi, that are introduced in the Azores, were screened for parasites using PCR primers known to amplify Apicomplexa parasites, and using nematode-specific primers. With the former, three different organisms were detected: Hepatozoon, a trichodinid protozoan ciliate and a possible Stramenopile. Using the latter set of primers, a single unknown spirurid nematode was also detected. Phylogenetic analyses indicate that Hepatozoon detected within amphibian hosts appear to form a clade, although relationships of these parasites do not match the vertebrate intermediate host phylogeny. Regarding the possible Stramenopile, it is unclear whether this organism was actually present on the amphibian or in the water on the surface of the tissue sample. Our findings highlight that many different organisms can be detected with these primers and that they can be used to screen introduced host populations to detect parasites that have been brought with them. PMID:24338327

James Harris, D; Spigonardi, Maria Pia; Maia, João P M C; Cunha, Regina T

2013-12-01

374

The Ins and Outs of Nuclear Trafficking: Unusual Aspects in Apicomplexan Parasites  

PubMed Central

Apicomplexa is a phylum within the kingdom Protista that contains some of the most significant threats to public health. One of the members of this phylum, Toxoplasma gondii, is amenable to molecular genetic analyses allowing for the identification of factors critical for colonization and disease. A pathway found to be important for T. gondii pathogenesis is the Ran network of nuclear trafficking. Bioinformatics analysis of apicomplexan genomes shows that while Ran is well conserved, the key regulators of Ran—Regulator of Chromosome Condensation 1 and Ran GTPase activating protein—are either highly divergent or absent. Likewise, several import and export receptor molecules that are crucial for nuclear transport are either not present or have experienced genetic drift such that they are no longer recognizable by bioinformatics tools. In this minireview we describe the basics of nuclear trafficking and compare components within apicomplexans to defined systems in humans and yeast. A detailed analysis of the nuclear trafficking network in these eukaryotes is required to understand how this potentially unique cellular biological pathway contributes to host–parasite interactions. PMID:19348590

Frankel, Matthew B.

2009-01-01

375

Sex allocation and population structure in apicomplexan (protozoa) parasites.  

PubMed Central

Establishing the selfing, rate of parasites is important for studies in clinical and epidemiological medicine as well as evolutionary biology Sex allocation theory offers a relatively cheap and easy way to estimate selfing rates in natural parasite populations. Local mate competition (LMC) theory predicts that the optimal sex ratio (r*; defined as proportion males) is related to the selfing rate (s) by the equation r* = (1-s)/2. In this paper, we generalize the application of sex allocation theory across parasitic protozoa in the phylum Apicomplexa. This cosmopolitan phylum consists entirely of parasites, and includes a number of species of medical and veterinary importance. We suggest that LMC theory should apply to eimeriorin intestinal parasites. As predicted, data from 13 eimeriorin species showed a female-biased sex ratio, with the sex ratios suggesting high levels of selfing (0.8-1.0). Importantly, our estimate of the selfing rate in one of these species, Toxoplasma gondii, is in agreement with previous genetic analyses. In contrast, we predict that LMC theory will not apply to the groups in which syzygy occurs (adeleorins, gregarines and piroplasms). Syzygy occurs when a single male gametocyte and a single female gametocyte pair together physically or in close proximity, just prior to fertilization. As predicted, data from four adeleorin species showed sex ratios not significantly different from 0.5. PMID:10714880

West, S A; Smith, T G; Read, A F

2000-01-01

376

Endoplasmic reticulum continuity in the protozoan parasite Entamoeba histolytica: Evolutionary implications and a cautionary note.  

PubMed

Entamoeba histolytica has been described as an early branching eukaryotic parasite based on the lack of organelles such as mitochondria and peroxisomes, and on morphologic studies that concluded it possesses a vesicular endoplasmic reticulum (ER) and Golgi complex. However, a recent study from our laboratory showed that the E. histolytica ER is continuous by using an ER-targeted green fluorescent protein fusion protein and photobleaching experiments. We proposed that the vesicular ER seen earlier was likely an artifact of fixation. We now report data using an alternative fixation protocol that preserves the continuous ER morphology. These data confirm that the vesicular ER reported earlier was indeed a fixation artifact; furthermore, since we observed the same ER structure when staining for the native antigen HSP-70 in wild-type amebae, the data provide direct evidence that the continuous ER morphology we reported is correct. This work has important implications for cell biologists studying E. histolytica virulence, emphasizes the frequent need to reassess assumptions based on published data, and provides additional evidence that E. histolytica actually diverged relatively late in evolution and that many of its unusual features are likely due to loss of features during adaptation to its ecological niche. PMID:19704884

Vaithilingam, Archana; Teixeira, Jose E; Huston, Christopher D

2008-01-01

377

Rates of Benthic Protozoan Grazing on Free and Attached Sediment Bacteria Measured with Fluorescently Stained Sediment  

PubMed Central

In order to determine the importance of benthic protozoa as consumers of bacteria, grazing rates have been measured by using monodispersed fluorescently labeled bacteria (FLB). However, high percentages of nongrazing benthic protists are reported in the literature. These are related to serious problems of the monodispersed FLB method. We describe a new method using 5-(4,6-dichlorotriazin-2-yl)-aminofluorescein (DTAF)-stained sediment to measure in situ bacterivory by benthic protists. This method is compared with the monodispersed FLB technique. Our estimates of benthic bacterivory range from 61 to 73 bacteria protist-1 h-1 and are about twofold higher than the results of the monodispersed FLB method. The number of nongrazing protists after incubation for 15 min with DTAF-stained sediment is in agreement with theoretical expectation. We also tested the relative affinity for FLB of protists and discuss the results with respect to a grazing model. PMID:16349315

Starink, Mathieu; Krylova, Irina N.; Bär-Gilissen, Marie-José; Bak, Rolf P. M.; Cappenberg, Thomas E.

1994-01-01

378

Benthic Bacterial Production and Protozoan Predation in a Silty Freshwater Environment  

Microsoft Academic Search

The interrelation of heterotrophic bacteria with bacterivorous protists has been widely studied in pelagic environments, but data on benthic habitats, especially in freshwater systems, are still scarce. We present a seasonal study focusing on bacterivory by heterotrophic nanoflagellates (HNF) and ciliates in the silty sediment of a temperate macrophyte-dominated oxbow lake. From January 2001 to February 2002 we monitored the

C. Wieltschnig; U. R. Fischer; A. K. T. Kirschner; B. Velimirov

2003-01-01

379

Estimates of protozoan-and viral-mediated mortality of bacterioplankton in Lake Bourget (France)  

E-print Network

) STE´ PHAN JACQUET,* ISABELLE DOMAIZON, SE´ BASTIEN PERSONNIC,* ANGIA SRIRAM PRADEEP RAM, MIKAL HEDAL (Kepner, Wharton & Suttle, Correspondence: Ste´phan Jacquet, UMR CARRTEL, Equipe de Microbiologie Aquatique, Station INRA d'Hydrobiologie Lacustre, 74203 Thonon cedex, France. E-mail: jacquet

Jacquet, Stéphan

380

GAC adsorption filters as barriers for viruses, bacteria and protozoan (oo)cysts in water treatment.  

PubMed

Granular Activated Carbon (GAC) adsorption filtration is commonly used in drinking water treatment to remove NOM and micro-pollutants and on base of the process conditions a certain capacity to eliminate pathogenic micro-organisms was expected. The experiences with the mandatory quantitative microbial risk assessment of Dutch drinking water revealed a lack of knowledge on the elimination capacity of this process for pathogens. The objective of the current study was to determine the capacity of GAC filtration to remove MS2, Escherichia coli and spores of Clostridium bifermentans as process indicators for pathogens and more directly of (oo)cysts of Cryptosporidium parvum and Giardia lamblia. Challenge tests with fresh and loaded GAC were performed in pilot plant GAC filters supplied with pre-treated surface water at a contact time which was half of the contact time of the full-scale GAC filters. MS2 phages were not removed and the removal of E. coli and the anaerobic spores was limited ranging from < or =0.1-1.1 log. The (oo)cysts of C. parvum and G. lamblia, however, were removed significantly (1.3-2.7 log). On base of the results of the experiments and the filtration conditions the removal of the indicator bacteria and (oo)cysts was largely attributed to attachment. The model of the Colloid Filtration Theory was used to describe the removal of the dosed biocolloids in the GAC filters, but the results demonstrated that there is a lack of quantitative knowledge about the influence of collector characteristics on the two major CFT parameters, the single collector and the sticking efficiency. PMID:19892384

Hijnen, W A M; Suylen, G M H; Bahlman, J A; Brouwer-Hanzens, A; Medema, G J

2010-02-01

381

UPTAKE, DISTRIBUTION, AND BIOCONVERSION OF FLUORESCENT LIPID ANALOGS IN THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS  

EPA Science Inventory

It has been established that host lipids play a unique role for long term survival and life cycle completion in endogenous parasites. Parasites exploit fatty acids and lipids from the host, not only for membrane synthesis, but also for modification of their surface integrity to a...

382

Microfluidic Trap Arrays: Passive Sensors for Studying Aquatic Protozoan Ecology and Biogeography  

NASA Astrophysics Data System (ADS)

Microscopic organisms such as bacteria and protozoa are the engine that drives global biogeochemical processes: microbes fix carbon, produce oxygen, mediate nutrient cycling, and break down anthropogenic contaminants. In many habitats, the bacterial community structure and its net production is controlled in a top-down fashion by predation by protozoa. Despite their importance, many researchers have noted a significant gap in our understanding of their diversity, biogeography, and ecosystem function. We developed a microfluidic field sampling and analysis tool to study the biogeography and function of microbial eukaryotes. Microfluidic samplers were created to systematically target the morphology, function, and habitat of different microbial eukaryotes. Features such as channel dimensions, branching angles and radii of curvature were varied to allow organisms to be selected and captured based on cell size, shape, plasticity, and swimming or crawling modalities. We also developed genetic analysis protocols to extract and amplify DNA from a single trapped cell, allowing for molecular identification of trapped species. Results from freshwater sediment and water column deployments confirmed design efficiencies in trapping and concentrating protozoa based on biomass density, allowed for analysis of body plasticity and cell size, and also confirmed the viability of this technology for future real time monitoring of protozoa in aquatic ecosystems. This research offers a radical departure from existing approaches to study microbial eukaryotic communities in the field. Our novel methodology involving trapping, observation and recording of physical characteristics and genetic analysis of single cells allows comparison with bulk samples to place trapped microbes within a function- and habitat-specific context.

Chau, J. F.; Bouchillon, G.; Shor, L. M.

2012-12-01

383

EFFECT OF GROWTH RATE AND HYDROPHOBICITY ON BACTERIA SURVIVING PROTOZOAN GRAZING  

EPA Science Inventory

Measurements were made of the predation by Tetrahymena thermophila on several bacterial species in media containing heat-killed Escherichia cells to serve as an alternative prey. f grazing pressure was initially not intense on a mixture of bacterial species, the species that surv...

384

EFFECT OF PROTOZOAN PREDATION ON RELATIVE ABUNDANCE OF FAST- AND SLOW-GROWING BACTERIA  

EPA Science Inventory

Survival of six bacterial species with different growth rates was tested in raw sewage and sewage rendered free of protozoa. hen the six species were inoculated at the same densities into sewage containing protozoa, the three slow-growing species were rapidly eliminated, and two ...

385

Cellulase andOtherPolymer-Hydrolyzing Activities of Trichomitopsis termopsidis, a Symbiotic Protozoan fromTermitest  

Microsoft Academic Search

Phylogenetically lowertermites dependondenseand diverse populations ofhindgut protozoa andbacteria to thrive byxylophagy, andourcurrent understanding ofthis nutritional symbiosis hasbeenrecently reviewed (4-6, 19). Amongthis heterogeneous microbial community, itappears that anaerobic, flagellate protozoa arethemajor, ifnotsole, agents ofwoodcellulose hydrolysis. Theyarenotonly abundant inthehindgut, buttheyalsohavetheability to endocytose, andthereby sequester, woodparticles forintra- cellular degradation. Majorproducts ofcellulose fermenta- tionbymixedandaxenic suspensions oftheprotozoa include H2,C02,andacetate (12, 13,21,29,30), withthe latter compound serving

JOHNA. BREZNAK

1985-01-01

386

Metabolic Reprogramming during Purine Stress in the Protozoan Pathogen Leishmania donovani  

PubMed Central

The ability of Leishmania to survive in their insect or mammalian host is dependent upon an ability to sense and adapt to changes in the microenvironment. However, little is known about the molecular mechanisms underlying the parasite response to environmental changes, such as nutrient availability. To elucidate nutrient stress response pathways in Leishmania donovani, we have used purine starvation as the paradigm. The salvage of purines from the host milieu is obligatory for parasite replication; nevertheless, purine-starved parasites can persist in culture without supplementary purine for over three months, indicating that the response to purine starvation is robust and engenders parasite survival under conditions of extreme scarcity. To understand metabolic reprogramming during purine starvation we have employed global approaches. Whole proteome comparisons between purine-starved and purine-replete parasites over a 6–48 h span have revealed a temporal and coordinated response to purine starvation. Purine transporters and enzymes involved in acquisition at the cell surface are upregulated within a few hours of purine removal from the media, while other key purine salvage components are upregulated later in the time-course and more modestly. After 48 h, the proteome of purine-starved parasites is extensively remodeled and adaptations to purine stress appear tailored to deal with both purine deprivation and general stress. To probe the molecular mechanisms affecting proteome remodeling in response to purine starvation, comparative RNA-seq analyses, qRT-PCR, and luciferase reporter assays were performed on purine-starved versus purine-replete parasites. While the regulation of a minority of proteins tracked with changes at the mRNA level, for many regulated proteins it appears that proteome remodeling during purine stress occurs primarily via translational and/or post-translational mechanisms. PMID:24586154

Soysa, Radika; Alfaro, Joshua F.; Yang, Feng; Burnum-Johnson, Kristin E.; Petyuk, Vladislav A.; Weitz, Karl K.; Camp, David G.; Smith, Richard D.; Wilmarth, Phillip A.; David, Larry L.; Ramasamy, Gowthaman; Myler, Peter J.; Carter, Nicola S.

2014-01-01

387

CONCERNS RELATED TO PROTOZOAN AND HELMINTH PARASITES IN BIOSOLIDS AND ANIMAL WASTES  

Technology Transfer Automated Retrieval System (TEKTRAN)

This in-depth review of parasites found in municipal wastewater effluents, biosolids, or animal wastes and considered to be a concern to public health includes the protozoa Cryptosporidium, Cyclospora, Toxoplasma, Microsporidia, Balantidium, Giardia, and Entamoeba as well as the helminths Trichuris,...

388

OrthoSearch: a scientific workflow approach to detect distant homologies on protozoans  

Microsoft Academic Search

Managing bioinformatics experiments is challenging due to the orchestration and interoperation of tools with semantics. An effective approach for managing those experiments is through workflow management systems (WfMS). We present several WfMS features for supporting genome homology workflows and discuss relevant issues for typical genomic experiments. In our evaluation we used OrthoSearch, a real genomic pipeline originally defined as a

Sérgio Manuel Serra Da Cruz; Vanessa Batista; Alberto M. R. Dávila; Edno Silva; Frederico Tosta; Clarissa Vilela; Maria Luiza Machado Campos; Rafael R. C. Cuadrat; Diogo A. Tschoeke; Marta Mattoso

2008-01-01

389

RNA editing and mitochondrial genomic organization in the cryptobiid kinetoplastid protozoan Trypanoplasma borreli.  

PubMed Central

The bodonids and cryptobiids represent an early diverged sister group to the trypanosomatids among the kinetoplastid protozoa. The trypanosome type of uridine insertion-deletion RNA editing was found to occur in the cryptobiid fish parasite Trypanoplasma borreli. A pan-edited ribosomal protein, S12, and a novel 3'- and 5'-edited cytochrome b, in addition to an unedited cytochrome oxidase III gene and an apparently unedited 12S rRNA gene, were found in a 6-kb fragment of the 80- to 90-kb mitochondrial genome. The gene order differs from that in trypanosomatids, as does the organization of putative guide RNA genes; guide RNA-like molecules are transcribed from tandemly repeated 1-kb sequences organized in 200- and 170-kb molecules instead of minicircles. The presence of pan-editing in this lineage is consistent with an ancient evolutionary origin of this process. Images PMID:7969154

Maslov, D A; Simpson, L

1994-01-01

390

Novel features of a PIWI-like protein homolog in the parasitic protozoan Leishmania.  

PubMed

In contrast to nearly all eukaryotes, the Old World Leishmania species L. infantum and L. major lack the bona fide RNAi machinery genes. Interestingly, both Leishmania genomes code for an atypical Argonaute-like protein that possesses a PIWI domain but lacks the PAZ domain found in Argonautes from RNAi proficient organisms. Using sub-cellular fractionation and confocal fluorescence microscopy, we show that unlike other eukaryotes, the PIWI-like protein is mainly localized in the single mitochondrion in Leishmania. To predict PIWI function, we generated a knockout mutant for the PIWI gene in both L. infantum (Lin) and L. major species by double-targeted gene replacement. Depletion of PIWI has no effect on the viability of insect promastigote forms but leads to an important growth defect of the mammalian amastigote lifestage in vitro and significantly delays disease pathology in mice, consistent with a higher expression of the PIWI transcript in amastigotes. Moreover, amastigotes lacking PIWI display a higher sensitivity to apoptosis inducing agents than wild type parasites, suggesting that PIWI may be a sensor for apoptotic stimuli. Furthermore, a whole-genome DNA microarray analysis revealed that loss of LinPIWI in Leishmania amastigotes affects mostly the expression of specific subsets of developmentally regulated genes. Several transcripts encoding surface and membrane-bound proteins were found downregulated in the LinPIWI((-/-)) mutant whereas all histone transcripts were upregulated in the null mutant, supporting the possibility that PIWI plays a direct or indirect role in the stability of these transcripts. Although our data suggest that PIWI is not involved in the biogenesis or the stability of small noncoding RNAs, additional studies are required to gain further insights into the role of this protein on RNA regulation and amastigote development in Leishmania. PMID:23285111

Padmanabhan, Prasad K; Dumas, Carole; Samant, Mukesh; Rochette, Annie; Simard, Martin J; Papadopoulou, Barbara

2012-01-01

391

Transport behavior of groundwater protozoa and protozoan-sized microspheres in sandy aquifer sediments  

USGS Publications Warehouse

Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ cell size, 2 to 3 ??m) flagellates, which are relatively abundant in the Cape Cod aquifer, were isolated from core samples, grown in a grass extract medium, labeled with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer sediments along with bromide, a conservative tracer. The 2-??m flagellates appeared to be near the optimal size for transport, judging from flowthrough column experiments involving a polydispersed (0.7 to 6.2 ??m in diameter) suspension of carboxylated microspheres. However, immobilization within the aquifer sediments accounted for a log unit reduction over the first meter of travel compared with a log unit reduction over the first 10 m of travel for indigenous, free-living groundwater bacteria in earlier tests. High rates of flagellate immobilization in the presence of aquifer sediments also was observed in the laboratory. However, immobilization rates for the laboratory-grown flagellates (initially 4 to 5 ??m) injected into the aquifer were not constant and decreased noticeably with increasing time and distance of travel. The decrease in propensity for grain surfaces was accompanied by a decrease in cell size, as the flagellates presumably readapted to aquifer conditions. Retardation and apparent dispersion were generally at least twofold greater than those observed earlier for indigenous groundwater bacteria but were much closer to those observed for highly surface active carboxylated latex microspheres. Field and laboratory results suggest that 2- ??m carboxylated microspheres may be useful as analogs in investigating several abiotic aspects of flagellate transport behavior in groundwater.

Harvey, R.W.; Kinner, N.E.; Bunn, A.; MacDonald, D.; Metge, D.

1995-01-01

392

Helminths and protozoans of aquatic organisms as bioindicators of chemical pollution  

Microsoft Academic Search

There is no doubt that the aquatic environments receive large quantities of chemicals as conse- quence of human activities and that those substances have a detrimental effect on human health. Despite the obvious need for effective disposal of these substances, we need to understand and prevent the out- come of harmful environmental exposures. Thus, we need biomarkers and bioindicators to

V. M. Vidal Martínez

2007-01-01

393

Lipid Synthesis in Protozoan Parasites: a Comparison Between Kinetoplastids and Apicomplexans  

PubMed Central

Lipid metabolism is of crucial importance for pathogens. Lipids serve as cellular building blocks, signalling molecules, energy stores, posttranslational modifiers, and pathogenesis factors. Parasites rely on a complex system of uptake and synthesis mechanisms to satisfy their lipid needs. The parameters of this system change dramatically as the parasite transits through the various stages of its life cycle. Here we discuss the tremendous recent advances that have been made in the understanding of the synthesis and uptake pathways for fatty acids and phospholipids in apicomplexan and kinetoplastid parasites, including Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania. Lipid synthesis differs in significant ways between parasites from both phyla and the human host. Parasites have acquired novel pathways through endosymbiosis, as in the case of the apicoplast, have dramatically reshaped substrate and product profiles, and have evolved specialized lipids to interact with or manipulate the host. These differences potentially provide opportunities for drug development. We outline the lipid pathways for key species in detail as they progress through the developmental cycle and highlight those that are of particular importance to the biology of the pathogens and/or are the most promising targets for parasite-specific treatment. PMID:23827884

Ramakrishnan, Srinivasan; Serricchio, Mauro; Striepen, Boris; Bütikofer, Peter

2013-01-01

394

Artemisinin Induces Calcium-Dependent Protein Secretion in the Protozoan Parasite Toxoplasma gondii? †  

PubMed Central

Intracellular calcium controls several crucial cellular events in apicomplexan parasites, including protein secretion, motility, and invasion into and egress from host cells. The plant compound thapsigargin inhibits the sarcoplasmic-endoplasmic reticulum calcium ATPase (SERCA), resulting in elevated calcium and induction of protein secretion in Toxoplasma gondii. Artemisinins are natural products that show potent and selective activity against parasites, making them useful for the treatment of malaria. While the mechanism of action is uncertain, previous studies have suggested that artemisinin may inhibit SERCA, thus disrupting calcium homeostasis. We cloned the single-copy gene encoding SERCA in T. gondii (TgSERCA) and demonstrate that the protein localizes to the endoplasmic reticulum in the parasite. In extracellular parasites, TgSERCA partially relocalized to the apical pole, a highly active site for regulated secretion of micronemes. TgSERCA complemented a calcium ATPase-defective yeast mutant, and this activity was inhibited by either thapsigargin or artemisinin. Treatment of T. gondii with artemisinin triggered calcium-dependent secretion of microneme proteins, similar to the SERCA inhibitor thapsigargin. Artemisinin treatment also altered intracellular calcium in parasites by increasing the periodicity of calcium oscillations and inducing recurrent, strong calcium spikes, as imaged using Fluo-4 labeling. Collectively, these results demonstrate that artemisinin perturbs calcium homeostasis in T. gondii, supporting the idea that Ca2+-ATPases are potential drug targets in parasites. PMID:17766463

Nagamune, Kisaburo; Beatty, Wandy L.; Sibley, L. David

2007-01-01

395

Transport Behavior of Groundwater Protozoa and Protozoan-Sized Microspheres in Sandy Aquifer Sediments  

PubMed Central

Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ cell size, 2 to 3 (mu)m) flagellates, which are relatively abundant in the Cape Cod aquifer, were isolated from core samples, grown in a grass extract medium, labeled with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer sediments along with bromide, a conservative tracer. The 2-(mu)m flagellates appeared to be near the optimal size for transport, judging from flowthrough column experiments involving a polydispersed (0.7 to 6.2 (mu)m in diameter) suspension of carboxylated microspheres. However, immobilization within the aquifer sediments accounted for a log unit reduction over the first meter of travel compared with a log unit reduction over the first 10 m of travel for indigenous, free-living groundwater bacteria in earlier tests. High rates of flagellate immobilization in the presence of aquifer sediments also was observed in the laboratory. However, immobilization rates for the laboratory-grown flagellates (initially 4 to 5 (mu)m) injected into the aquifer were not constant and decreased noticeably with increasing time and distance of travel. The decrease in propensity for grain surfaces was accompanied by a decrease in cell size, as the flagellates presumably readapted to aquifer conditions. Retardation and apparent dispersion were generally at least twofold greater than those observed earlier for indigenous groundwater bacteria but were much closer to those observed for highly surface active carboxylated latex microspheres. Field and laboratory results suggest that 2-(mu)m carboxylated microspheres may be useful as analogs in investigating several abiotic aspects of flagellate transport behavior in groundwater. PMID:16534904

Harvey, R. W.; Kinner, N. E.; Bunn, A.; MacDonald, D.; Metge, D.

1995-01-01

396

Metabolic Profiling of the Protozoan Parasite Entamoeba invadens Revealed Activation of Unpredicted Pathway during Encystation  

PubMed Central

Encystation, which is cellular differentiation from the motile, proliferative, labile trophozoite form to the dormant, resistant cyst form, is a crucial process found in parasitic and free-living protozoa such as Entamoeba, Giardia, Acanthamoeba, and Balamuthia. Since encystation is an essential process to deal with the adverse external environmental changes during the life cycle, and often integral to the transmission of the diseases, biochemical understanding of the process potentially provides useful measures against the infections caused by this group of protozoa. In this study, we investigated metabolic and transcriptomic changes that occur during encystation in Entamoeba invadens, the reptilian sibling of mammal-infecting E. histolytica, using capillary electrophoresis-tandem mass spectrometry-based metabolite profiling and DNA microarray-based expression profiling. As the encystation progressed, the levels of majority of metabolites involved in glycolysis and nucleotides drastically decreased, indicating energy generation is ceased. Furthermore, the flux of glycolysis was redirected toward chitin wall biosynthesis. We found remarkable temporal increases in biogenic amines such as isoamylamine, isobutylamine, and cadaverine, during the early period of encystation, when the trophozoites form large multicellular aggregates (precyst). We also found remarkable induction of ?-aminobutyric acid (GABA) during encystation. This study has unveiled for the first time the dynamics of the transcriptional and metabolic regulatory networks during encystation, and should help in better understanding of the process in pathogenic eukaryotes, and further development of measures controlling infections they cause. PMID:22662204

Jeelani, Ghulam; Sato, Dan; Husain, Afzal; Escueta-de Cadiz, Aleyla; Sugimoto, Masahiro; Soga, Tomoyoshi; Suematsu, Makoto; Nozaki, Tomoyoshi

2012-01-01

397

Structure-function analysis of antimicrotubule dinitroanilines against promastigotes of the parasitic protozoan Leishmania mexicana.  

PubMed Central

Although leishmaniasis is a major tropical disease, the currently available drugs are toxic and inadequate. We show that the antimicrotubule herbicide trifluralin has antileishmania activity. The present study aimed at deducing the relationship between the structure of the molecule and its antiprotozoan activity. Nine dinitroanilines, all of which were analogs of trifluralin, were compared. We found that pendimethalin was 2.5-fold more potent than trifluralin, and the higher efficacy may be correlated with molecular structural features that increase the accessibility to one nitro group. This association was further supported by molecular modeling. Moreover, trifluralin samples from two sources differed in their activities by more than threefold, and gas column chromatography showed that impurities were present in the more potent sample. PMID:7818612

Chan, M M; Tzeng, J; Emge, T J; Ho, C T; Fong, D

1993-01-01

398

The major surface-metalloprotease of the parasitic protozoan, Leishmania, protects against antimicrobial  

E-print Network

peptide degradation by wild-type parasites. Pexiganan-treatment of knock out mutants induced disruption antimicrobial peptide-induced apoptotic killing Manjusha M. Kulkarni,1 W. Robert McMaster,2 Elzbieta Kamysz,3 of mitochondrial membrane potential, exposure of surface phosphatidyl serine as well as induction of caspase 3

Engman, David M.

399

Elongation Factor-1? Is a Novel Protein Associated with Host Cell Invasion and a Potential Protective Antigen of Cryptosporidium parvum *  

PubMed Central

The phylum Apicomplexa comprises obligate intracellular parasites that infect vertebrates. All invasive forms of Apicomplexa possess an apical complex, a unique assembly of organelles localized to the anterior end of the cell and involved in host cell invasion. Previously, we generated a chicken monoclonal antibody (mAb), 6D-12-G10, with specificity for an antigen located in the apical cytoskeleton of Eimeria acervulina sporozoites. This antigen was highly conserved among Apicomplexan parasites, including other Eimeria spp., Toxoplasma, Neospora, and Cryptosporidium. In the present study, we identified the apical cytoskeletal antigen of Cryptosporidium parvum (C. parvum) and further characterized this antigen in C. parvum to assess its potential as a target molecule against cryptosporidiosis. Indirect immunofluorescence demonstrated that the reactivity of 6D-12-G10 with C. parvum sporozoites was similar to those of anti-?- and anti-?-tubulins antibodies. Immunoelectron microscopy with the 6D-12-G10 mAb detected the antigen both on the sporozoite surface and underneath the inner membrane at the apical region of zoites. The 6D-12-G10 mAb significantly inhibited in vitro host cell invasion by C. parvum. MALDI-TOF/MS and LC-MS/MS analysis of tryptic peptides revealed that the mAb 6D-12-G10 target antigen was elongation factor-1? (EF-1?). These results indicate that C. parvum EF-1? plays an essential role in mediating host cell entry by the parasite and, as such, could be a candidate vaccine antigen against cryptosporidiosis. PMID:24085304

Matsubayashi, Makoto; Teramoto-Kimata, Isao; Uni, Shigehiko; Lillehoj, Hyun S.; Matsuda, Haruo; Furuya, Masaru; Tani, Hiroyuki; Sasai, Kazumi

2013-01-01

400

A new species of Eimeria (Apicomplexa: Eimeriidae) from the northern myotis, Myotis septentrionalis (Chiroptera: Vespertilionidae), in Oklahoma.  

PubMed

During September 2004, 4 adult northern myotis, Myotis septentrionalis, were collected from LeFlore County, Oklahoma (n ?=? 2), and Logan (n ?=? 1) and Yell (n ?=? 1) counties, Arkansas, and their feces examined for coccidian parasites. Three of 4 bats (75%) were passing oocysts of Eimeria spp. Oocysts of Eimeria tumlisoni n. sp. were subspherical, 17.6 × 16.8 (16-19 × 14-18) µm with a shape index of 1.0 (1.0-1.1). A micropyle and oocyst residuum were absent, although 1-2 bilobed polar granules were often present. Sporocysts were ovoidal, 10.5 × 5.9 (9-12 × 5-7) µm with a shape index of 1.8 (1.6-2.0). A Stieda body was present, but substieda and parastieda bodies were absent. A sporocyst residuum was present consisting of compact to dispersed granules between the sporozoites. The sporozoites were elongate, with subspherical anterior refractile body and spherical posterior refractile body; a nucleus was not discernable. This is the second coccidian reported from this host and the first instance of a bat coccidian reported from Oklahoma. We also document a new geographic record for Eimeria catronensis in Oklahoma and provide an emended description. PMID:22509940

McAllister, Chris T; Seville, R Scott; Roehrs, Zachary P

2012-10-01

401

Isospora plectrophenaxia n. sp (Apicomplexa: Eimeriidae), a new coccidian parasite found in Snow Bunting ( Plectrophenax nivalis ) nestlings on Spitsbergen  

Microsoft Academic Search

Faecal samples were collected from four 8 days old snow bunting nestlings from one nest in Ny-?lesund, Spitsbergen, in summer\\u000a 2006. After sporulation, samples were examined for coccidian parasites using flotation centrifuging. We found isosporan oocysts\\u000a in three birds, intensity of infection varied between individuals from 35 to 6,000 oocysts per defecation. All oocysts belonged\\u000a to one species, which is described

Olga V. Dolnik; Maarten J. J. E. Loonen

2007-01-01

402

Isospora plectrophenaxia n. sp (Apicomplexa: Eimeriidae), a new coccidian parasite found in Snow Bunting (Plectrophenax nivalis) nestlings on Spitsbergen.  

PubMed

Faecal samples were collected from four 8 days old snow bunting nestlings from one nest in Ny-Alesund, Spitsbergen, in summer 2006. After sporulation, samples were examined for coccidian parasites using flotation centrifuging. We found isosporan oocysts in three birds, intensity of infection varied between individuals from 35 to 6,000 oocysts per defecation. All oocysts belonged to one species, which is described here as a new species. The spherical or subspherical oocysts (Fig. 1) have a brownish, smooth, relatively thin (about 1.1 microm) bilayered wall. Average size of sporulated oocysts was 26.2 +/- 0.13 x 23.6 +/- 0.16 microm (24.1-28.4 x 21.5-26.9; n = 10) with a shape index (length/width) of 1.11 +/- 0.01 (1.01-1.29). The sporulated oocysts have no micropyle or residuum but enclose one large (3.3 x 2.8 microm) ring-formed polar granule. The sporocysts are ovoidal, slightly pointed at the end opposite the Stieda body, 18.2 +/- 0.06 x 9.9 +/- 0.03 microm (17.1-19.0 x 9.0-10.8; n = 14), shape index 1.85 +/- 0.008 (1.70-1.99). The Stieda body has a prominent knob-like cap and a well-visible round substieda body. Sporocysts contain compact sporocyst residuum composed of small, uniform granules and sporozoits with usually three large refractile bodies and a smaller nucleus. The prepatent period is less than 8 days. This is the first description of an avian isosporan parasite that succeeds transmission while in the High Arctic. PMID:17701217

Dolnik, Olga V; Loonen, Maarten J J E

2007-11-01

403

Red and problematic green phylogenetic signals among thousands of nuclear genes from the photosynthetic and apicomplexa-related Chromera velia.  

PubMed

The photosynthetic and basal apicomplexan Chromera velia was recently described, expanding the membership of this otherwise nonphotosynthetic group of parasite protists. Apicomplexans are alveolates with secondary plastids of red algal origin, but the evolutionary history of their nuclear genes is still actively discussed. Using deep sequencing of expressed genes, we investigated the phylogenetic affinities of a stringent filtered set of 3,151 expressed sequence tag-contigs by generating clusters with eukaryotic homologs and constructing phylogenetic trees and networks. The phylogenetic positioning of this alveolate alga was determined and sets of phyla-specific proteins extracted. Phylogenetic trees provided conflicting signals, with 444 trees grouping C. velia with the apicomplexans but 354 trees grouping C. velia with the alveolate oyster pathogen Perkinsus marinus, the latter signal being reinforced from the analysis of shared genes and overall sequence similarity. Among the 513 C. velia nuclear genes that reflect a photosynthetic ancestry and for which nuclear homologs were available both from red and green lineages, 263 indicated a red photosynthetic ancestry, whereas 250 indicated a green photosynthetic ancestry. The same 1:1 signal ratio was found among the putative 255 nuclear-encoded plastid proteins identified. This finding of red and green signals for the alveolate mirrors the result observed in the heterokont lineage and supports a common but not necessarily single origin for the plastid in heterokonts and alveolates. The inference of green endosymbiosis preceding red plastid acquisition in these lineages leads to worryingly complicated evolutionary scenarios, prompting the search for other explanations for the green phylogenetic signal and the amount of hosts involved. PMID:21965651

Woehle, Christian; Dagan, Tal; Martin, William F; Gould, Sven B

2011-01-01

404

DIFFERENTIAL IDENTIFICATION OF ASCOGREGARINA SPECIES (APICOMPLEXA: LECUDINIDAE) IN AEDES AEGYPTI AND AEDES ALBOPICTUS (DIPTERA: CULICIDAE) BY THE POLYMERASE CHAIN REACTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

We report two polymerase chain reaction (PCR)-based methods for distinguishing morphologically similar gregarine species based on amplification of variable regions of the internal transcribed spacer gene of ribosomal DNA. The gregarines we investigated were Ascogregarina barretti (Vavra), A. culici...

405

Comparison of the ITS1 and ITS2 rDNA in Emeria callospermophili (Apicomplexa: Eimeriidae) from Sciurid Rodents  

PubMed Central

The taxonomy of the coccidia has historically been morphologically based. The purpose of this study was to establish if conspecificity of isolates of Eimeria callospermophili from 4 ground-dwelling squirrel hosts (Rodentia: Sciuridae) is supported by comparison of rDNA sequence data and to examine how this species relates to eimerian species from other sciurid hosts. Eimeria callospermophili was isolated from 4 wild caught hosts, i.e., Urocitellus elegans, Cynomys leucurus, Marmota flaviventris, and Cynomys ludovicianus. The ITS1 and ITS2 genomic rDNA sequences were PCR generated, sequenced, and analyzed. The highest intraspecific pairwise distance values of 6.0% in ITS1 and 7.1% in ITS2 were observed in C. leucurus. Interspecific pairwise distance values greater than 5% do not support E. callospermophili conspecificity. Generated E. callospermophili sequences were compared to Eimeria lancasterensis from Sciuris niger and Sciurus niger cinereus, and Eimeria ontarioensis from S. niger. A single well-supported clade was formed by E. callospermophili amplicons in Neighbor Joining and Maximum Parsimony analyses. However, within the clade there was little evidence of host or geographic structuring of the species. PMID:21506777

Motriuk-Smith, Dagmara; Seville, R Scott; Quealy, Leah; Oliver, Clinton E.

2011-01-01

406

Two new species of Eimeria (Apicomplexa, Eimeriidae) from tree skinks, Prasinohaema spp. (Sauria: Scincidae), from Papua New Guinea  

USGS Publications Warehouse

Between September 1991 and June 1992, feces from 4 species of tree skinks, Prasinohaema spp. from Papua New Guinea, were collected and examined for coccidia. Two species, P. flavipes and P. prehensicauda were found to harbor eimerians which are described as new. Oocysts of Eimeria krausi sp. nov. from P. flavipes were ellipsoidal to subspheroidal with a smooth bilayered wall and measured (L × W) 19.2 × 16.9 ?m, with a length/width (L/W) ratio of 1.1. Micropyle and oocyst residuum were absent but a fragmented polar granule was present. Sporocysts were ellipsoidal, 9.7 × 6.7 ?m, L/W of 1.5. Stieda, subStieda and paraStieda bodies were absent. The sporocyst residuum was composed of many small granules in a compact mass between sporozoites. The sporozoites were sausage-shaped, 11.7 × 2.7 ?m, in situ, with an ellipsoidal posterior refractile body and a spheroidal anterior refractile body. Oocysts of Eimeria greeri sp. nov. from P. prehensicauda were ellipsoidal with a smooth bilayered wall, (L × W) 23.0 × 18.3 ?m, with a L/W of 1.3. Micropyle and oocyst residuum were absent but a fragmented polar granule was present. Sporocysts were ellipsoidal, 9.7 × 8.4 ?m, with a L/W of 1.2. Stieda, subStieda and paraStieda bodies were absent. The sporocyst residuum was composed of many large granules in a compact mass between sporozoites. The sporozoites were sausage-shaped, with an ellipsoidal posterior refractile body and a spheroidal anterior refractile body. We document here the first report of coccidia from skinks of the genus Prasinohaema.

McAllister, Chris T.; Duszynski, Donald W.; Fisher, Robert N.; Austin, Christopher C.

2014-01-01

407

Two new species of Isospora (Apicomplexa: Eimeriidae) from skinks Emoia spp. (Sauria: Scincidae), from Fiji and Papua New Guinea  

USGS Publications Warehouse

Between September and October 1991 and again during September 1992, skinks (Emoia spp.) were collected from various localities on Fiji and Papua New Guinea (PNG) and examined for coccidians. One of 4 (25%) De Vis' emo skinks (Emoia pallidiceps) from PNG harbored an undescribed species of Isospora in its feces. Oocysts of Isospora grinbikpelapalai n. sp. were ellipsoidal to subspheroidal, 18.1 × 14.9 (17–20 × 14–16) ?m, with a bilayered wall and a length/width index (L/W) of 1.2. Both micropyle and oocyst residuum were absent, but a prominent polar granule was present. Sporocysts were ovoidal, 10.7 × 7.6 (10–11 × 7–8) ?m, with a L/W index of 1.4. Stieda and sub-Stieda bodies were present, but para-Stieda bodies were absent. The sporocyst residuum consisted of large scattered globules dispersed between sporozoites. Sporozoites were elongate with spheroidal anterior and posterior refractile bodies. Isospora grinbikpelapalai was also found in 1 of 2 (50%) Pope's emo skinks (Emoia popei) from PNG. One of 13 (8%) white-bellied copper-striped skinks (Emoia cyanura), from Fiji, was passing another undescribed species of Isospora in its feces. Oocysts of Isospora casei n. sp. were elongate, 31.8 × 21.3 (28–35 × 18–24) ?m, with a bilayered wall and a L/W index of 1.5. Micropyle, oocyst residuum, and polar granule were all absent. Sporocysts were ovoidal, 15.3 × 10.6 (14–16 × 10–12) ?m, with a L/W index of 1.4. Stieda and sub-Stieda bodies were present, but para-Stieda bodies were absent. The sporocyst residuum consisted of scattered globules among sporozoites or as a cluster surrounding sporozoites. Sporozoites were elongate with spheroidal anterior and posterior refractile bodies. Isospora casei was also found in 1 of 2 (50%) Fiji slender treeskinks (Emoia concolor) from Fiji. This represents the first report of coccidia from Emoia spp. and, to our knowledge, the initial documentation of reptilian coccidia from herpetofauna from Papua New Guinea.

McAllister, Chris T.; Duszynski, Donald W.; Fisher, Robert N.

2013-01-01

408

Haemoproteus ilanpapernai n. sp. (Apicomplexa, Haemoproteidae) in Strix seloputo from Singapore: morphological description and reassignment of molecular data  

PubMed Central

Haemoproteus ilanpapernai Karadjian and Landau n. sp. from the Spotted Wood Owl, Strix seloputo, in Singapore is described from material from Ilan Paperna’s collection of slides. The species was previously identified as Haemoproteus syrnii (Mayer, 1910). However, comparisons between the material from Strix seloputo and our own material from Strix aluco, the type host of H. syrnii, revealed morphological and molecular differences. H. ilanpapernai n. sp. differs morphologically from H. syrnii by the much smaller size of the gametocytes, the different position of the mature gametocytes in the erythrocyte (apical, subapical, or lateral in H. ilanpapernai vs. always lateral in H. syrnii), the effect on the erythrocyte nucleus (frequently tilted in H. ilanpapernai but not displaced laterally vs. straight and displaced laterally in H. syrnii) and characters of the pigment (aggregated in the gametocytes of H. ilanpapernai vs. dispersed in H. syrnii). A molecular analysis showed that the two species differ by 2.9% at the cyt b and 3.1% at the COI genes. PMID:24759652

2014-01-01

409

A NEW SPECIES OF HEPATOZOON (APICOMPLEXA: ADELEORINA) FROM PYTHON REGIUS (SERPENTES: PYTHONIDAE) AND ITS EXPERIMENTAL TRANSMISSION BY A MOSQUITO VECTOR  

Microsoft Academic Search

Hepatozoon ayorgbor n. sp. is described from specimens of Python regius imported from Ghana. Gametocytes were found in the peripheral blood of 43 of 55 snakes examined. Localization of gametocytes was mainly inside the erythrocytes; free gametocytes were found in 15 (34.9%) positive specimens. Infections of laboratory-reared Culex quinquefasciatus feeding on infected snakes, as well as experimental infection of juvenile

Michal Sloboda; Martin Kamler; Jana Bulantová; Jan Votýpka; David Modrý

2007-01-01

410

Babesia microti (Apicomplexa: Piroplasmida): Electron microscope detection in salivary glands of the tick vector Ixodes ricinus (Ixodoidea: Ixodidae)  

Microsoft Academic Search

Ultrastructures of the rodent piroplasm Babesia microti Franga, 1912 have been studied in blood stages of the parasite in mammalian hosts (G6bel et al. 1978) and in the intestine of a susceptible tick species, Ixodes dammini (Rudzinska et al. 1979). Developmental stages of B. microti in the salivary glands of ticks have not been described so far. We have now

Giinter Weber; Gottfried Walter

1980-01-01

411

Microscopic and molecular characterization of Hepatozoon domerguei (Apicomplexa) and Foleyella furcata (Nematoda) in wild endemic reptiles from Madagascar  

PubMed Central

Madagascar is one of the world’s top twelve “megadiversity” hot spots hosting unique and threatened flora and fauna. Parasites are a major component of biodiversity but remain largely uncharacterized in wildlife. In this study we combine microscopic and molecular assessment of hemoparasites in endemic reptile species from Madagascar. We detected three distinct parasites: the apicomplexans Hepatozoon and Sarcocystis, and filarial nematodes. The prevalence and intensity of these apicomplexans were low overall, while microfilarial infections in chameleons were relatively high. We detected mixed infections of two Hepatozoon haplotypes in Madagascarophis colubrinus, and of Hepatozoon and microfilariae in a Furcifer sp. Phylogenetic analyses of Hepatozoon showed evidence of prey-predator transmission, with identical sequences found in the snakes M. colubrinus and Ithycyphus oursi, and their prey Furcifer sp. Based on previous studies regarding the life cycle of Hepatozoon domerguei Landau, Chabaud, Michel, and Brygoo, 1970 in these hosts and due to their morphological similarity, we propose that this Hepatozoon haplotype is Hepatozoon domerguei. Future studies, including the examination of invertebrate hosts, are needed to verify this preliminary taxonomic identification. A distinct hemogregarine haplotype was found in Oplurus sp., which displayed morphologically different gametocytes, some of which were apparently inside leukocytes. The Sarcocystis identified from Tracheloptychus petersi was identical to that reported in a North African snake, indicating that the same lineage is found in geographically distinct regions. By combining morphological and genetic information, Foleyella furcata (Linstow, 1899) filarial nematodes were identified in several Furcifer chameleons. This study provides insights into the distribution, diversity and host-parasite interactions of hemoparasites in wild reptile populations from Madagascar. PMID:25224723

Maia, João P.; Crottini, Angelica; Harris, David James

2014-01-01

412

A New Species of Eimeria (Apicomplexa: Eimeriidae) from the marbled salamander, Ambystoma opacum (Caudata: Ambystomatidae), from northern Louisiana.  

PubMed

Between December 2002 and June 2004, 10 marbled salamanders, Ambystoma opacum, were examined for coccidian parasites. Salamanders were collected in Bradley (n = 2), Little River (n = 1), Miller (n = 1), and Sevier (n = 1) Counties, Arkansas; Webster Parish, Louisiana (n = 2); and Bowie (n = 1) and Nacogdoches (n = 2) Counties, Texas. Two of 10 (20%) A. opacum from Louisiana harbored an undescribed species of Eimeria. Oocysts of Eimeria trauthi n. sp. were ellipsoidal, 36.6 x 33.1 (33-40 x 29-37) microm, with a thin, single-layered wall; shape index 1.1. Polar granule(s) and micropyle were absent. Oocyst residuum was composed of hundreds of loosely packed homogenous granules of various sizes enclosing a vacuole. Sporocysts were elongate-ellipsoidal, 20.8 x 8.1 (19-22 x 7-9) microm; shape index 2.6. Sporocyst residuum was spherical and composed of a cluster of granules often membrane-bound. This is the first time a coccidium has been reported from an amphibian species in Louisiana and the second time a coccidium has been described from this salamander host. In addition, the following 26 salamanders from various counties in Arkansas, Oklahoma, and Texas were surveyed during the study period and were negative for coccidia: Ambystomatidae, 4 spotted salamanders (Ambystoma maculatum) and 7 mole salamanders (Ambystoma talpoideum); Cryptobranchidae, 4 Ozark hellbenders (Cryptobranchus alleganiensis bishopi); Plethodontidae, 6 spotted dusky salamanders (Desmognathus conanti) and 3 many-ribbed salamanders (Eurycea multiplicata multiplicata); and Salamandridae, 2 central newts (Notophthalmus viridescens louisianensis). PMID:18605797

McAllister, Chris T; Upton, Steve J

2008-06-01

413

A revision of the taxonomy and nomenclature of the Eimeria spp. (Apicomplexa: Eimeriidae) from rodents in the Tribe Marmotini (Sciuridae)  

Microsoft Academic Search

All published papers on Eimeria spp. from rodents in the Marmotini Tribe are reviewed and each described species is evaluated in an historical context (i.e., beginning with the oldest description). Many of these species descriptions from marmotine rodents are invalid when considered within either the spirit or the letter of the International Code of Zoological Nomenclature. In addition, several previous

Patricia G. Wilber; D. W. Duszynski; S. J. Upton; R. S. Seville; J. O. Corliss

1998-01-01

414

A NEW SPECIES OF EIMERIA (APICOMPLEXA: EIMERIIDAE) FROM THE EASTERN PIPISTRELLE, PERIMYOTIS SUBFLAVUS (CHIROPTERA: VESPERTILIONIDAE), IN ARKANSAS  

PubMed Central

During November 2009 and March 2010, 20 adult eastern pipistrelles, Perimyotis (=Pipistrellus) subflavus were collected from Polk County, Arkansas, and their feces examined for coccidian parasites. Two (10%) of the bats were found to be passing oocysts of an undescribed species of Eimeria. Oocysts of Eimeria heidti n. sp. were ovoidal to ellipsoidal, 26.1 × 20.5 (23-31 × 18-23) ?m, with a bilayered wall, externally rough, internally smooth, and with a shape index of 1.3. Micropyle and oocyst residuum were absent, but a subspherical polar granule was often present. Sporocysts were ovoidal, 13.0 × 8.8 (11-15 × 7-13) ?m, the shape index was 1.6, a Stieda body was present and sub-Stieda and para-Stieda bodies were absent. A sporocyst residuum consisting of multiple globules dispersed along the perimeter of the sporocyst and between the sporozoites were present, sporozoites were elongate, with a subspherical anterior refractile body and elongate posterior refractile body; a nucleus not discernable. This is the second coccidian reported from this host and the fourth instance of a coccidian species reported from an Arkansas bat. PMID:21506799

McAllister, Chris T.; Burt, Scott; Seville, R. Scott; Robison, Henry W.

2011-01-01

415

New host and locality records of coccidia (Apicomplexa: Eimeriidae) from rodents in the southwestern and western United States.  

PubMed

One hundred forty-seven murid and heteromyid rodents were collected from various sites in the southwestern and western United States (Arizona, Colorado, New Mexico, Texas, and Utah) and Baja California Norte, Mexico, and their feces were examined for coccidial parasites. Of these, 53 (36%) were infected with at least 1 coccidian; 45 of 53 (85%) of the infected rodents harbored only 1 species of coccidian. Infected rodents included: 10 of 22 (45%) Neotoma albigula, 3 of 11 (27%) Neotoma floridana, 2 of 14 (14%) Neotoma lepida, 15 of 29 (52%) Neotoma micropus, 5 of 8 (63%) Peromyscus crinitis, 6 of 6 (100%) Peromyscus difficilis, 1 of 2 (50%) Peromyscus eremicus, 9 of 34 (26%) Sigmodon hispidis, and 2 of 3 (67%) Sigmodon ochrognathus; 4 Neotoma cinerea, 3 Neotoma devia, 3 Neotoma mexicana, 1 Peromyscus maniculatus, 1 Onychomys leucogaster, 1 Onychomys torridus, 3 Chaetodipus fallax, and 2 Chaetodipus penicillatus were negative. Although no new species was found, the following coccidians were identified from infected rodents: Eimeria albigulae from N. albigula, N. floridana, and N. micropus, Eimeria antonellii from N. albigula and N. micropus, Eimeria ladronensis from N. albigula, N. floridana, N. lepida, and N. micropus, Eimeria arizonensis and Eimeria lachrymalis from P. crinitis and P. difficilis, Eimeria lachrymalis from P. eremicus, Eimeria tuskeegensis from S. ochrognathus, and Eimeria roperi, Eimeria sigmodontis, Eimeria tuskeegensis, Eimeria webbae, and an unidentified species of Eimeria from S. hispidis. This report documents 12 new host and several distributional records for Eimeria species from murid rodents in Arizona, Texas, and Utah. PMID:1779282

McAllister, C T; Upton, S J; Planz, J V; DeWalt, T S

1991-12-01

416

A NEW SPECIES OF EIMERIA (APICOMPLEXA: EIMERIIDAE) FROM THE NORTHERN MYOTIS, MYOTIS SEPTENTRIONALIS (CHIROPTERA: VESPERTILIONIDAE), IN OKLAHOMA  

PubMed Central

During September 2004, 4 adult northern myotis, Myotis septentrionalis, were collected from LeFlore County, Oklahoma (n = 2), and Logan (n = 1) and Yell (n = 1) counties, Arkansas, and their feces examined for coccidian parasites. Three of 4 bats (75%) were passing oocysts of Eimeria spp. Oocysts of Eimeria tumlisoni n. sp. were ovoidal, 17.6 × 16.8 (16–19 × 14–18) ?m with a shape index of 1.0 (1.0–1.1). A micropyle and oocyst residuum were absent, although 1–2 bilobed polar granules were often present. Sporocysts were ovoidal, 10.5 × 5.9 (9–12 × 5–7) ?m with a shape index of 1.8 (1.6–2.0). A Stieda body was present, but sub–Stieda and para–Stieda bodies were absent. A sporocyst residuum was present consisting of compact to dispersed granules between the sporozoites. The sporozoites were elongate, with subspherical anterior refractile body and spherical posterior refractile body; a nucleus was not discernable. This is the second coccidian reported from this host and the first instance of a bat coccidian reported from Oklahoma. We also document a new geographic record for Eimeria catronensis in Oklahoma, and provide an emended description. PMID:22509940

McAllister, Chris T.; Seville, R. Scott; Roehrs, Zachary P.

2012-01-01

417

Isospora thibetana N. sp. (Apicomplexa, Eimeriidae), a parasite of the Tibetan siskin (Serinus thibetanus = Carduelis thibetanus) (Passeriformes, Fringillidae).  

PubMed

Tibetan siskins are birds native to the Himalayan region often imported into Italy for commercial purposes. Fecal examination of 45 imported subjects with clinical signs of diarrhoea revealed the presence of a large number of coccidian oocysts. After sporulation, accomplished by mixing feces with 2.5% (w/v) aqueous K2Cr2O7 at room temperature (22 degrees C +/- 1 degree C), exogenous stages of an Isospora species were revealed. The oocysts of this Isospora are spherical, have a bilayered colorless wall, and average 23.24 microm x 23.05 microm; oocyst residuum and micropyle are absent, while an oval polar granule is rarely present. The elliptical sporocysts average 18.44 microm x 10.97 microm and the Stieda body protrudes slightly from the end of the sporocyst. A spherical sporocyst residuum, is present though it sometimes consists of scattered granules. The spindle-shaped sporozoites average 11.53 microm x 2.86 microm, and have two refractile bodies. The taxonomic position of the tibetan siskin is controversial. Some authors include this species in the genus Serinus, while others include it in the genus Carduelis. The coccidian species isolated from these tibetan siskins was, for this reason, compared with the Isospora species previously described both in the genus Carduelis and in the genus Serinus. As a result of this comparison a new species, Isospora thibetana, was named. In the intestine of dead subjects, oocysts were found only in the ileum where the mucosa was greatly thickened and presented a heavy leucocytic infiltration consisting mainly of lympho-monocytic cells. A similar infiltration was observed in liver and lungs as well. PMID:9616037

Perrucci, S; Rossi, G; Macchioni, G

1998-01-01

418

Eimeria lancasterensis (Apicomplexa: Eimeriidae) from the eastern fox squirrel, Sciurus niger (Rodentia: Sciuridae), in north-central Texas.  

PubMed

Eimeria lancasterensis Joseph, 1969, is reported for the first time from the feces of 10 of 11 (91%) eastern fox squirrels, Sciurus niger ludovicianus, in Dallas and Johnson counties, Texas. Oocyst measurements were similar to those reported previously from the eastern gray squirrel, Sciurus carolinensis carolinensis, in Massachusetts. Except for our observation of a substieda body, oocyst morphology was identical to the original description of E. lancasterensis. PMID:2760777

McAllister, C T; Upton, S J

1989-08-01

419

Differential identification of Ascogregarina species (Apicomplexa: Lecudinidae) in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) by polymerase chain reaction.  

PubMed

We report 2 polymerase chain reaction (PCR)-based methods for distinguishing morphologically similar gregarine species based on amplification of variable regions of the internal transcribed spacer region of ribosomal DNA. The gregarines we investigated were Ascogregarina barretti (Vavra), A. culicis (Ross), and A. taiwanensis (Lien and Levine), parasites of the mosquitoes Ochlerotatus triseriatus (Say), Aedes aegypti (Linnaeus), and Ae. albopictus (Skuse), respectively. These 3 important vector mosquitoes often utilize the same container habitats, where larval development and infection by the parasite occurs, leaving ample opportunity for cross-species gregarine infection. Because previous studies have shown that the parasites A. culicis and A. taiwanensis variably affect fitness in both normal and abnormal mosquito hosts, distinguishing parasite infection and species is important. The task is complicated by the fact that these 2 parasite species are virtually identical in morphology, whereas A. barretti is morphologically distinct. Of the 2 PCR-based assays reported here, the first provides a rapid, sensitive, and straight-forward means of general ascogregarine detection based on a single PCR amplification. The second method provides a means of differentiation between A. culicis and A. taiwanensis based on a species-specific PCR assay. Together, these assays allow whole mosquitoes to be tested for the presence of Ascogregarina species as well as identification of both A. culicis and A. taiwanensis singly or in dual infections. PMID:16539016

Morales, Maria E; Ocampo, Clara B; Cadena, Horacio; Copeland, Claudia S; Termini, Michael; Wesson, Dawn M

2005-12-01

420

A new species of Monocystis stein, 1848 (Protista: Apicomplexa: Eugregarinida) from the Indian earthworm, Amynthas Hawayanus Rosa, 1891 (Annelida: Oligochaeta).  

PubMed

As a part of an ongoing biodiversity survey of aseptate gregarine fauna of oligochaete hosts of West Bengal, an expedition was carried out in the Darjeeling district of West Bengal and most of the earthworms collected were found to be infested with a species of Monocystis Stein, 1848. The monocystid species was collected from the seminal vesicles of the earthworm and was identified as a new species, Monocystis amynthae sp. nov. The gamont of the new species is characterized by having an elongated body with broad anterior end, separated from the narrow posterior end by a prominent constriction measuring 49.0-77.0 (66.0+/-1.3) microm x 32.0-41.0 (37.0+/-2.8) microm. The gametocysts are oval-shaped, measuring 40.0-65.0 (58.0+/-2.1) microm. The oocysts are navicular, measuring 8.0-12.0 (10.5+/-1.1) microm x 4.0-6.0 (5.5+/-1.1) microm. PMID:17124669

Bandyopadhyay, Probir K; Göçmen, Bayram; Bhowmik, Biplab; Mitra, Amlan Kumar

2006-01-01

421

Identification of a Divergent Environmental DNA Sequence Clade Using the Phylogeny of Gregarine Parasites (Apicomplexa) from Crustacean Hosts  

PubMed Central

Background Environmental SSU rDNA surveys have significantly improved our understanding of microeukaryotic diversity. Many of the sequences acquired using this approach are closely related to lineages previously characterized at both morphological and molecular levels, making interpretation of these data relatively straightforward. Some sequences, by contrast, appear to be phylogenetic orphans and are sometimes inferred to represent “novel lineages” of unknown cellular identity. Consequently, interpretation of environmental DNA surveys of cellular diversity rely on an adequately comprehensive database of DNA sequences derived from identified species. Several major taxa of microeukaryotes, however, are still very poorly represented in these databases, and this is especially true for diverse groups of single-celled parasites, such as gregarine apicomplexans. Methodology/Principal Findings This study attempts to address this paucity of DNA sequence data by characterizing four different gregarine species, isolated from the intestines of crustaceans, at both morphological and molecular levels: Thiriotia pugettiae sp. n. from the graceful kelp crab (Pugettia gracilis), Cephaloidophora cf. communis from two different species of barnacles (Balanus glandula and B. balanus), Heliospora cf. longissima from two different species of freshwater amphipods (Eulimnogammarus verrucosus and E. vittatus), and Heliospora caprellae comb. n. from a skeleton shrimp (Caprella alaskana). SSU rDNA sequences were acquired from isolates of these gregarine species and added to a global apicomplexan alignment containing all major groups of gregarines characterized so far. Molecular phylogenetic analyses of these data demonstrated that all of the gregarines collected from crustacean hosts formed a very strongly supported clade with 48 previously unidentified environmental DNA sequences. Conclusions/Significance This expanded molecular phylogenetic context enabled us to establish a major clade of intestinal gregarine parasites and infer the cellular identities of several previously unidentified environmental SSU rDNA sequences, including several sequences that have formerly been discussed broadly in the literature as a suspected “novel” lineage of eukaryotes. PMID:21483868

Rueckert, Sonja; Simdyanov, Timur G.; Aleoshin, Vladimir V.; Leander, Brian S.

2011-01-01