15 Papers found (0.01 seconds)

Fan PC et al. (1985) Southeast Asian J Trop Med Public Health "Experimental infection of subperiodic Brugia malayi in laboratory rats with emphasis on evaluation by four techniques."

Hsu YP, Huang CM, Wu CC, Ho CM, Fan PC

[

Southeast Asian J Trop Med Public Health,

1985]

Infective larvae of subperiodic B. malayi from South Kalimantan (Borneo), Indonesia collected from laboratory-raised Ae. togoi mosquitoes after feeding on infected mongolian gerbils (Meriones unguiculatus) were inoculated subcutaneously into the groin areas of 15 SD and 36 LE rats. Blood was examined weekly by membrane filtration and thick smears starting 10 weeks post-infection. Microfilariae were found in 3 SD and 4 LE rats, the mf infection rate of 20% and 11% respectively. The prepatent period was significantly shorter in the SD rats (99-112 days) than those in the LE rats (110-153 days). The patent period was longer in the LE rats (208-703 days) than in the SD rats (236-543 days), and the mf density was similar (17.5 mf/20 c.mm blood against 16 mf/20 c.mm blood). At necropsy, 6 (3 female and 3 male) adult worms were recovered from 3 of 6 SD rats and 12 (9 female and 3 male) adult worms from 4 of 20 LE rats; all worms were found in the testes. The results of xenodiagnostic, histochemical staining and measuring spicules and protuberances, demonstrated clearly the difference between both species of Brugia. All dissected Ar. subalbatus mosquitoes exposed to B. pahangi became infected (100%), but none of those to subperiodic B. malayi were infected (0%). The mf of both species of Brugia in thick films stained with naphthol-AS-TR-phosphate showed that the excretory and anal pores of subperiodic B. malayi mf exhibited acid phosphatase activity and only a little activity was seen in other parts; while B. pahangi mf showed heavy diffuse acid phosphatase activity along the entire length of the body.(ABSTRACT TRUNCATED AT 250 WORDS)

Nolan RA (1972) Mycologia "Asteromyces cruciatus from North America."

Nolan RA

[

Mycologia,

1972]

The hyphomycete Asteromyces cruciatus F. & Mme Moreau was described without a Latin diagnosis or a designated type. The taxon was validated by Hennebert. The known distribution of this monotypic genus has been limited. F. and Mme Moreau found the fungus in sand dunes at Point du Siege (under Psamma sp.) and between Franceville and Le Home (under Agropyrum sp.) on the Normandy coast of France. Brown found A. cruciatus in open sand in the intertidal zone at Studland, Dorset and Sandwich, Kent, England; and Nicot found it in sand dunes and beach samples at Malo-les-Bains on the North Sea coast of France.

Dougherty EC (1953) J Parasitol "The axenic cultivation of Rhabditis briggsae Dougherty and Nigon, 1949 (Nematoda: Rhabditidae). III. Liver preparations with various supplementation."

Dougherty EC

[

J Parasitol,

1953]

The axenic cultivation (i.e., growth in the absence of other living organisms) of the free-living soil nematode, Rhabditis briggsae, requires a complex medium including one or more heat-labile, protein-like substances which have been termed "factor Rb". It has been shown that factor Rb can be provided by preparations from liver or chick embryo juice or by human plasma or certain of its fractions. Moreover, it has recently been reported in abstract that a dialysed fraction of buffered aqueous liver extract will support excellent growth of R. briggsae when supplemented with known substances only. The present paper reports the results of recent studies on the nature and properties of factor Rb in liver protein and on various supplementations of certain unheated liver preparations as media for R. briggsae. Aqueous, unheated horse liver extract (hereinafter referred to as LE), prepared by centrifuging liver homogenate and taking supernatant, has been treated in various ways to provide information on the properties of factor Rb. Such preparations have been variously supplemented and tested as media for the axenic cultivation of R. briggsae. The principle supplementation used has been the supernatant (ALE) from autoclaved LE. Both partly and completely defined supplementations have also been employed. From these studies some advance has been made in the direction of a completely defined medium for R.

Franz CJ et al. (2012) J Virol "Complete genome sequence of Le Blanc virus, a third Caenorhabditis nematode-infecting virus."

Felix MA, Zhao G, Franz CJ, Wang D

[

J Virol,

2012]

Orsay virus and Santeuil virus, the first known viruses capable of naturally infecting the nematodes Caenorhabditis elegans and Caenorhabditis briggsae, respectively, were recently identified by high-throughput sequencing of wild Caenorhabditis strains. By similar analysis of another wild C. briggsae isolate, we have now discovered and sequenced the complete genome of a third novel virus, Le Blanc virus, that is distantly related to Orsay and Santeuil viruses. All three viruses are positive-sense RNA viruses with bipartite genomes that are most closely related to nodaviruses. Identification of a third virus capable of infecting Caenorhabditis nematodes enables comparative analysis of this clade of viruses and strengthens this model for investigating virus-host interactions.

Eberhardt AG et al. (2008) Vet Parasitol "The Strongyloides (Nematoda) of sheep and the predominant Strongyloides of cattle form at least two different, genetically isolated populations."

Mayer WE, Eberhardt AG, Streit A, Bonfoh B

[

Vet Parasitol,

2008]

Strongyloides sp. (Nematoda) are very wide spread small intestinal parasites of vertebrates that can form a facultative free-living generation. Most authors considered all Strongyloides of farm ruminants to belong to the same species, namely Strongyloides papillosus (Wedl, 1856). Here we show that, at least in southern Germany, the predominant Strongyloides found in cattle and the Strongyloides found in sheep belong to separate, genetically isolated populations. While we did find mixed infections in cattle, one form clearly dominated. This variety, in turn, was never found in sheep, indicating that the two forms have different host preferences. We also present molecular tools for distinguishing the two varieties, and an analysis of their phylogenetic relationship with the human parasite Strongyloides stercoralis and the major laboratory model species Strongyloides ratti. Based on our findings we propose that Strongyloides from sheep and the predominant Strongyloides from cattle should be considered separate species as it had already been proposed by [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l''evolution des Anguillules parasites (Strongyloides). Comptes rendu hebdomadaires des seances et memoires de la Societe de Biologie et de ses filiales 85, 149-152], but was largely ignored by later authors. For nomenclature, we follow [Brumpt, E., 1921. Recherches sur le determinisme des sexes et de l''evolution des Anguillules parasites (Strongyloides). Comptes rendu hebdomadaires des seances et memoires de la Societe de Biologie et de ses filiales 85, 149-152] and use the name S. papillosus for the Strongyloides of sheep and the name Strongyloides vituli for the predominant Strongyloides of cattle.

Frezal L et al. (2019) J Virol "Noda-like RNA viruses infecting Caenorhabditis nematodes: sympatry, diversity and reassortment."

Felix MA, Jung H, Frezal L, Tahan S, Wang D

[

J Virol,

2019]

Three RNA viruses related to nodaviruses were previously described to naturally infect the nematode Caenorhabditis elegans and its relative Caenorhabditis briggsae. Here we report on a collection of over 50 viral variants from wild-caught Caenorhabditis. We describe the discovery of a new related virus, the Mlnik virus, infecting C. briggsae, which similarly infects intestinal cells. In France, a frequent pattern of co-infection of C. briggsae by the Santeuil virus and Le Blanc virus was observed at the level of an individual nematode and even a single cell. We do not find evidence of reassortment between the RNA1 and RNA2 molecules of Santeuil and Le Blanc viruses. However, by studying patterns of evolution of each virus, reassortments of RNA1 and RNA2 among variants of each virus were identified. We develop assays to test the relative infectivity and competitive ability of the viral variants and detect an interaction between host genotype and Santeuil virus genotype, such that the result depends on the host strain.IMPORTANCE The roundworm Caenorhabditis elegans is a laboratory model organism in biology. We study natural populations of this small animal and its relative C. briggsae and the viruses that infect them. We previously discovered three RNA viruses related to nodaviruses and here describe a fourth one, called the Mlnik virus. These viruses have a genome composed of two RNA molecules. We find that two viruses may infect the same animal and the same cell. The two RNA molecules may be exchanged between variants of a given viral species. We study the diversity of each viral species and devise an assay of their infectivity and competitive ability. Using this assay, we show that the outcome of the competition also depends on the host.

Franz CJ et al. (2014) Virology "Orsay, Santeuil and Le Blanc viruses primarily infect intestinal cells in Caenorhabditis nematodes."

Felix MA, Frezal L, Renshaw H, Wang D, Jiang Y, Franz CJ

[

Virology,

2014]

The discoveries of Orsay, Santeuil and Le Blanc viruses, three viruses infecting either Caenorhabditis elegans or its relative Caenorhabditis briggsae, enable the study of virus-host interactions using natural pathogens of these two well-established model organisms. We characterized the tissue tropism of infection in Caenorhabditis nematodes by these viruses. Using immunofluorescence assays targeting proteins from each of the viruses, and in situ hybridization, we demonstrate viral proteins and RNAs localize to intestinal cells in larval stage Caenorhabditis nematodes. Viral proteins were detected in one to six of the 20 intestinal cells present in Caenorhabditis nematodes. In Orsay virus-infected C. elegans, viral proteins were detected as early as 6h post-infection. The RNA-dependent RNA polymerase and capsid proteins of Orsay virus exhibited different subcellular localization patterns. Collectively, these observations provide the first experimental insights into viral protein expression in any nematode host, and broaden our understanding of viral infection in Caenorhabditis nematodes.

Felix MA et al. (2019) Annu Rev Genet "Natural Viruses of Caenorhabditis Nematodes."

Felix MA, Wang D

[

Annu Rev Genet,

2019]

Caenorhabditis elegans has long been a laboratory model organism with no known natural pathogens. In the past ten years, however, natural viruses have been isolated from wild-caught C. elegans (Orsay virus) and its relative Caenorhabditis briggsae (Santeuil virus, Le Blanc virus, and Melnik virus). All are RNA positive-sense viruses related to Nodaviridae; they infect intestinal cells and are horizontally transmitted. The Orsay virus capsid structure has been determined and the virus can be reconstituted by transgenesis of the host. Recent use of the Orsay virus has enabled researchers to identify evolutionarily conserved proviral and antiviral genes that function in nematodes and mammals. These pathways include endocytosis through SID-3 and WASP; a uridylyltransferase that destabilizes viral RNAs by uridylation of their 3' end; ubiquitin protein modifications and turnover; and the RNA interference pathway, which recognizes and degrades viral RNA. Expected final online publication date for the Annual Review of Genetics, Volume 53 is November 23, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Larsen PL et al. (1995) Genetics "Genes that regulate both development and longevity in Caenorhabditis elegans."

Albert PS, Riddle DL, Larsen PL

[

Genetics,

1995]

The nematode Caenorhabditis elegans responds to conditions of overcrowding and limited food by arresting development as a dauer larva. Genetic analysis of mutations that alter dauer larva formation (daf mutations) is presented along with an updated genetic pathway for dauer vs. nondauer development. Mutations in the daf-2 and daf-23 genes double adult life span, whereas mutations in four other dauer-constitutive genes positioned in a separate branch of this pathway (daf-1, daf-4, daf-7 and daf-8) do not. The increased life spans are suppressed completely by a daf-16 mutation and partially in a daf-2; daf-18 double mutant. A genetic pathway for determination of adult life span is presented based on the same strains and growth conditions used to characterize Daf phenotypes. Both dauer larva formation and adult life span are affected in daf-2; daf-12 double mutants in an allele-specific manner. Mutations in daf-12 do not extend adult life span, but certain combinations of daf-2 and daf-le mutant alleles nearly quadruple it. This synergistic effect, which does not equivalently extend the fertile period, is the largest genetic extension of life span yet observed in a metazoan.

Guo YR et al. (2020) J Virol "Orsay CP- adopts a novel -bracelet structural fold and incorporates into virions as a head fiber."

Zhou Y, Holt MV, Fan Y, Wang D, Wang T, Guo YR, Zhong W, Tao YJ, Zhang JL, Jin M, Young NL, Jiang H

[

J Virol,

2020]

Fiber proteins are commonly found in eukaryotic and prokaryotic viruses where they play important roles in mediating viral attachment and host cell entry. They typically form trimeric structures and are incorporated into virions via non-covalent interactions. The small RNA virus Orsay, which specifically infects the laboratory model Caenorhabditis elegans, encodes a fibrous protein that can be expressed as a free protein and as a capsid protein- (CP-) fusion protein. Free has previously been demonstrated to facilitate viral exit following intracellular expression; however, the biological significance and prevalence of CP- remained relatively unknown. Here, we demonstrate that Orsay CP- is covalently incorporated into infectious particles, the first example of any attached viral fibers known to date. The crystal structure of (1-101) (i.e. a deletion mutant containing the first 101 amino acid (aa) residues of ) reveals a pentameric, 145-A long fiber with an N-terminal coiled coil followed by multiple -bracelet repeats. Electron micrographs of infectious virions depict particle-associated CP- fibers with dimensions similar to free . proteins from two other nematode viruses Le Blanc and Santeuil, which both specifically infect Caenorhabditis briggsae, were also found to form fibrous molecules. Recombinant Le Blanc was able to block Orsay virus infection in worm culture and vice versa, suggesting these two viruses likely compete for the same cell receptor(s). Thus, we propose that while CP- likely mediates host cell attachment for all three nematode viruses, additional downstream factor(s) ultimately determine the host specificity and range of each virus.IMPORTANCE Viruses often have extended fibers to mediate host cell recognition and entry, serving as promising targets for antiviral drug development. Unlike other known viral fibers, the proteins from the three recently discovered nematode viruses are incorporated into infectious particles as protruding fibers covalently linked to the capsid. Crystal structures of revealed novel pentameric folding repeats, which we term -bracelets, in the intermediate shaft region. Based on sequence analysis, the -bracelet motif of is conserved in all three nematode viruses and could account for 60% of the total length of the fiber. Our study indicated that plays important roles in cell attachment for this group of nematode viruses. In addition, the tightly knitted -bracelet fold, which presumably allows to survive harsh environments in the worm gut, could serve applicable to bioengineering applications given its potentially high stability.

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