Identificação molecular de Heterodera glycines, o nematóide de cistos da soja.

2008

Diagnóstico molecular para o nematóide Rotylenchulus reniformis.

2008

Identificação molecular de nematóides de galhas, Meloidogyne spp.

2008

Aspectos gerais sobre nematóides das lesões radiculares (gênero Pratylenchus).

2008

BRS 399RR: soja precoce e resistente a nematóides.

BRS 399RR: soja precoce e resistente a nematóides, grupo de maturidade relativa: 6.0 ; Precocidade; Sanidade; Regiões Edafoclimáticas de Adaptação (REC); Época de semeadura; Ciclo, Acamamento e Densidade de plantas; Características gerais; Reação a doenças.

WormSizer: high-throughput analysis of nematode size and shape.

The fundamental phenotypes of growth rate, size and morphology are the result of complex interactions between genotype and environment. We developed a high-throughput software application, WormSizer, which computes size and shape of nematodes from brightfield images. Existing methods for estimating volume either coarsely model the nematode as a cylinder or assume the worm shape or opacity is invariant. Our estimate is more robust to changes in morphology or optical density as it only assumes radial symmetry. This open source software is written as a plugin for the well-known image-processing framework Fiji/ImageJ. It may therefore be extended easily. We evaluated the technical performance of this framework, and we used it to analyze growth and shape of several canonical Caenorhabditis elegans mutants in a developmental time series. We confirm quantitatively that a Dumpy (Dpy) mutant is short and fat and that a Long (Lon) mutant is long and thin. We show that daf-2 insulin-like receptor mutants are larger than wild-type upon hatching but grow slow, and WormSizer can distinguish dauer larvae from normal larvae. We also show that a Small (Sma) mutant is actually smaller than wild-type at all stages of larval development. WormSizer works with Uncoordinated (Unc) and Roller (Rol) mutants as well, indicating that it can be used with mutants despite behavioral phenotypes. We used our complete data set to perform a power analysis, giving users a sense of how many images are needed to detect different effect sizes. Our analysis confirms and extends on existing phenotypic characterization of well-characterized mutants, demonstrating the utility and robustness of WormSizer.

Metazoan operons accelerate recovery from growth-arrested states.

Existing theories explain why operons are advantageous in prokaryotes, but their occurrence in metazoans is an enigma. Nematode operon genes, typically consisting of growth genes, are significantly upregulated during recovery from growth-arrested states. This expression pattern is anticorrelated to nonoperon genes, consistent with a competition for transcriptional resources. We find that transcriptional resources are initially limiting during recovery and that recovering animals are highly sensitive to any additional decrease in transcriptional resources. We provide evidence that operons become advantageous because, by clustering growth genes into operons, fewer promoters compete for the limited transcriptional machinery, effectively increasing the concentration of transcriptional resources and accelerating recovery. Mathematical modeling reveals how a moderate increase in transcriptional resources can substantially enhance transcription rate and recovery. This design principle occurs in different nematodes and the chordate C. intestinalis. As transition from arrest to rapid growth is shared by many metazoans, operons could have evolved to facilitate these processes.

To plasticity and back again.

Both the gain and the loss of flexibility in the development of phenotypes have led to an increased diversity of physical forms in nematode worms.

Nematode diversity in different microhabitats in a mangrove region

Mangroves are highly productive environments that play important ecological and socioeconomic roles; however, they have been impacted to different degrees in most countries worldwide. The knowledge of which organisms inhabit this environment and their ecological interactions is the first step towards its conservation. The natural variability of environmental factors in mangroves provides numerous niches available to different species. Meiofauna have patchy patterns of distribution that are related to the availability of resources. Hence, meiofauna are expected to present a high diversity of different taxa occupying the different microhabitats offered by mangroves. This work aims to test the hypothesis that the assemblage structure of Nematoda varies significantly among mangrove microhabitats and to contribute knowledge on the meiofauna diversity in mangrove environments. This work was carried out in a mangrove region at Pernambuco state, Northeastern Brazil. Qualitative samples were collected in nine microhabitats which show different characteristics mainly in terms of presence of vegetation or another organism and sediment grain size. Univariate and multivariate analysis were applied to Nematoda genera abundance data. Our results demonstrate the existence of significant differences among microhabitats regarding nematode assemblage structure corroborating the hypothesis. Different Nematoda assemblages are present in at least seven microhabitats. These assemblages are composed of nematode genera with different trophic and morphological features, demonstrating a strong relationship between morphological diversity and ecological plasticity. Furthermore, this study also demonstrates the importance of the conservation of this ecosystem and its attributes.

The FLP-side of nematodes.

The central role of FMRFamide-like peptides (FLPs) in nematode motor and sensory capabilities makes FLP signalling an appealing target for new parasiticides. Accumulating evidence has revealed an astounding level of FLP sequence conservation and diversity in the phylum Nematoda, and preliminary work has begun to identify the nematode FLP receptor complement in Caenorhabditis elegans, with a view to investigating their basic biology and therapeutic potential. However, much work is needed to clarify the functional aspects of FLP signalling and how these peptides exert their effects at the organismal level. Here, we summarize our current knowledge of nematode FLP signalling.

Parasitic peptides! The structure and function of neuropeptides in parasitic worms

Parasitic worms come from two very different phyla-Platyhelminthes (flatworms) and Nematoda (roundworms). Although both phyla possess nervous systems with highly developed peptidergic components. there are key differences in the structure and action of native neuropeptides in the two groups. For example, the most abundant neuropeptide known in platyhelminths is the pancreatic polypeptide-like neuropeptide F, whereas the most prevalent neuropeptides in nematodes an FMRFamide-related peptides (FaRPs), which are also present in platyhelminths. With respect to neuropeptide diversity, platyhelminth species possess only one or two distinct FaRPs, whereas nematodes have upwards of 50 unique FaRPs. FaRP bioactivity in platyhelminths appears to be restricted to myoexcitation, whereas both excitatory and inhibitory effects have been reported in nematodes. Recently interest has focused on the peptidergic signaling systems of both phyla because elucidation of these systems will do much to clarify the basic biology of the worms and because the peptidergic systems hold the promise of yielding novel targets for a new generation of antiparasitic drugs. (C) 1999 Elsevier Science Inc. All rights reserved.

PEPTIDES RELATED TO THE DIPLOPTERA-PUNCTATA ALLATOSTATINS IN NONARTHROPOD INVERTEBRATES - AN IMMUNOCYTOCHEMICAL SURVEY

The allatostatins are a family of peptides isolated originally from the cockroach, Diploptera punctata. Related peptides have been identified in Periplaneta americana and the blowfly, Calliphora vomitoria. These peptides have been shown to be potent inhibitors of juvenile hormone synthesis in these species. A peptide inhibitor of juvenile hormone biosynthesis has also been isolated from the moth, Manduca sexta; however, this peptide has no structural homology with the D. punctata-type allatostatins. Investigations of the phylogeny of the D. punctata allatostatin peptide family have been started by examining a number of nonarthropod invertebrates for the presence of allatostatin-like molecules using immunocytochemistry with antisera directed against the conserved C-terminal region of this family. Allatostatin-like immunoreactivity (ALIR) was demonstrated in the nervous systems of Hydra oligactis (Hydrozoa), Moniezia expansa (Cestoda), Schistosoma mansoni (Trematoda), Artioposthia triangulata (Turbellaria), Ascaris suum (Nematoda), Lumbricus terrestris (Oligochaeta), Limax pseudoflavus (Gastropoda), and Eledone cirrhosa (Cephalopoda). ALIR could not be demonstrated in Ciona intestinalis (Ascidiacea). These results suggest that molecules related to the allatostatins may play an important role in nervous system function in many invertebrates as well as in insects and that they also have an ancient evolutionary lineage. (C) 1994 Wiley-Liss, Inc.

New insights into sequence variation in the IGS region of 21 cyathostomin species and the implication for molecular identification

Cyathostomins comprise a group of 50 species of parasitic nematodes that infect equids. Ribosomal DNA sequences, in particular the intergenic spacer (IGS) region, have been utilized via several methodologies to identify pre-parasitic stages of the commonest species that affect horses. These methods rely on the availability of accurate sequence information for each species, as well as detailed knowledge of the levels of intra- and inter-specific variation. Here, the IGS DNA region was amplified and sequenced from 10 cyathostomin species for which sequence was not previously available. Also, additional IGS DNA sequences were generated from individual worms of 8 species already studied. Comparative analysis of these sequences revealed a greater range of intra-specific variation than previously reported (up to 23%); whilst the level of inter-specific variation (3-62%) was similar to that identified in earlier studies. The reverse line blot (RLB) method has been used to exploit the cyathostomin IGS DNA region for species identification. Here, we report validation of novel and existing DNA probes for identification of cyathostomins using this method and highlight their application in differentiating life-cycle stages such as third-stage larvae that cannot be identified to species by morphological means.

Parasite neuropeptide biology:Seeding rational drug target selection?

The rationale for identifying drug targets within helminth neuromuscular signalling systems is based on the premise that adequate nerve and muscle function is essential for many of the key behavioural determinants of helminth parasitism, including sensory perception/host location, invasion, locomotion/orientation, attachment, feeding and reproduction. This premise is validated by the tendency of current anthelmintics to act on classical neurotransmitter-gated ion channels present on helminth nerve and/or muscle, yielding therapeutic endpoints associated with paralysis and/or death. Supplementary to classical neurotransmitters, helminth nervous systems are peptide-rich and encompass associated biosynthetic and signal transduction components - putative drug targets that remain to be exploited by anthelmintic chemotherapy. At this time, no neuropeptide system-targeting lead compounds have been reported, and given that our basic knowledge of neuropeptide biology in parasitic helminths remains inadequate, the short-term prospects for such drugs remain poor. Here, we review current knowledge of neuropeptide signalling in Nematoda and Platyhelminthes, and highlight a suite of 19 protein families that yield deleterious phenotypes in helminth reverse genetics screens. We suggest that orthologues of some of these peptidergic signalling components represent appealing therapeutic targets in parasitic helminths.