Nematology 

About: Nematology is an academic journal published by Brill. The journal publishes majorly in the area(s): Population & Meloidogyne incognita. It has an ISSN identifier of 1388-5545. Over the lifetime, 2058 publications have been published receiving 33432 citations. The journal is also known as: Nematology (Boston) & Nematology (Köln).

First report of Bursaphelenchus xylophilus in Portugal and in Europe

Abstract: A survey of aphelenchid nematodes (Nematoda: Aphelenchida) associated with maritime pine, Pinus pinaster, was conducted in Portugal in 1996 and 1999. A Bursaphelenchus species has been identified for the first time in the Iberian Peninsula. B. xylophilus is reported for the first time in Europe. It was found in very high numbers - up to 38 000 per 10 g of pine wood - inside a few declining trees infested with curculionid, cerambycid and scolytid beetles. Morphological observations, including shape of spicules, bursa, vulva, female tail end and stylet as well as morphometrics, were in accordance with the species description. Species-specific DNA fragment patterns were obtained using ITS-RFLP analysis, with five different restriction enzymes. The importance and implications of this finding are discussed. Premiere signalisation de Bursaphelenchus xylophilus au Portugal, at en Europe - Une enquete sur les nematodes Aphelenchides (Nematoda: Aphelenchida) associes au pin maritime (Pinus pinaster) a ete realisee au Portugal de 1996 a 1999. Une espece de Bursaphelenchus a ete identifiee pour la premiere fois dans la Peninsule Iberique. B. xylophilus est signale pour la premiere fois en Europe. Il a ete trouve en tres grand nombre - jusqu'a 38 000 individus pour 10 g de bois de pin - dans des arbres deperissants infestes par des Coleopteres Curculionides, Cerambycides et Scolytides. Les observations concernant la morphologie - en particulier la forme des spicules, la bourse, la vulve, l'extremite de la queue de la femelle et le stylet - de meme que les donnees morphometriques correspondent a la description de l'espece. Des sequences de fragments d'ADN specifique de l'espece ont ete obtenus par analyse ITS-RFLP a l'aide de cinq enzymes de restriction. L'importance et les implications de cette decouverte sont discutees.

A phylogenetic tree of nematodes based on about 1200 full-length small subunit ribosomal DNA sequences.

Abstract: As a result of the scarcity of informative morphological and anatomical characters, nematode systematics have always been volatile. Differences in the appreciation of these characters have resulted in numerous classifications and this greatly confuses scientific communication. An advantage of the use of molecular data is that it allows for an enormous expansion of the number of characters. Here we present a phylogenetic tree based on 1215 small subunit ribosomal DNA sequences (ca 1700 bp each) covering a wide range of nematode taxa. Of the 19 nematode orders mentioned by De Ley et al. (2006) 15 are represented here. Compared with Holterman et al. (2006) the number of taxa analysed has been tripled. This did not result in major changes in the clade subdivision of the phylum, although a decrease in the number of well supported nodes was observed. Especially at the family level and below we observed a considerable congruence between morphology and ribosomal DNA-based nematode systematics and, in case of discrepancies, morphological or anatomical support could be found for the alternative grouping in most instances. The extensiveness of convergent evolution is one of the most striking phenomena observed in the phylogenetic tree presented here - it is hard to find a morphological, ecological or biological characteristic that has not arisen at least twice during nematode evolution. Convergent evolution appears to be an important additional explanation for the seemingly persistent volatility of nematode systematics.

Molecular and morphological characterisation of two reproductively isolated species with mirror-image anatomy ({Nematoda}: {Cephalobidae})

Abstract: Detailed descriptions are given of the amphimictic nematode strains PS1158, PS2052 and PS2160, which are unusual in that they only differ in predominant body handedness. Although these strains are morphologically identical in all other respects, published reproductive data and new DNA sequence data of the D2/D3 region of the large subunit rRNA gene show that they do represent two separate species. On the basis of comparison with type material, the left-handed strains PS1158 and PS2160 are identified as Acrobeloides bodenheimeri , and the right-handed strain PS2052 as A. camberenensis , which is re-instated as a valid species. A. bodenheimeri and its relatives exhibit various types of diagnostic and taxonomic problems at species level, and it is shown that D2/D3 sequence data provide an important new diagnostic tool for addressing these problems. Phylogenetic analysis shows that two right-handed parthenogenetic strains identified as A. maximus represent a third species which is more closely related to A. camberenensis than to A. bodenheimeri . Caracterisation morphologique et moleculaire de deux especes intersteriles de chiralite contraire (Nematoda: Cephalobidae) - Une description detaillee est donnee des souches amphimictiques de nematodes PS1158, PS2052 et PS2160, souches inhabituelles car differant par la chiralite du corps. Bien que ces souches soient morphologiquement identiques sous tout autre rapport, les resultats publies de tests de croisement et de nouvelles donnees concernant la sequence d'ADN de la region D2/D3 du gene de la grosse sous-unite d'ARN ribosomal montrent qu'elles representent en fait deux especes distinctes. Se fondant sur une comparaison avec le materiel type, les souches sinistres PS1158 et PS2160 sont identifiees comme Acrobeloides bodenheimeri et la souche dextre PS2052 comme A. camberenensis , ainsi retabli comme espece valide. A. bodenheimeri et les especes proches posent differents problemes diagnostiques et taxinomiques au niveau specifique, et nous montrons que les donnees de sequence D2/D3 fournissent un nouvel outil diagnostique important pour aborder ces problemes. L'analyse phylogenetique montre que deux souches parthenogenetiques dextres identifiees comme A. maximus representent en fait une troisieme espece, plus proche de A. camberenensis que de A. bodenheimeri .

Identification of Meloidogyne incognita, M. javanica and M. arenaria using sequence characterised amplified region (SCAR) based PCR assays

Abstract: Three randomly amplified polymorphic DNA (RAPD) markers, OPA-12 420 , OPB-06 1200 and OPA-01 700 , species specific to the root-knot nematode species Meloidogyne arenaria , M. incognita and M. javanica respectively, were identified. After sequencing these RAPD-PCR products, longer primers of 18 to 23 nucleotides were designed to complement the terminal DNA sequences of the DNA fragments. This resulted in three pairs of species specific primers that were used to amplify the sequence characterised amplified regions (SCARs). The developed sets of SCAR primers were successfully used in straightforward, fast and reliable PCR assays to identify M. incognita , M. javanica and M. arenaria . The length variant SCAR markers can be amplified from DNA from egg masses, second stage juveniles and females. This species identification technique is therefore independent of the nematode's life cycle stage. Moreover the SCAR-PCR assay was successfully applied using DNA extracts from infested plant material. The method has potential to be optimised for routine practical diagnostic tests facilitating the control of these economically important pest organisms. Identification de Meloigyne incognita, M. javanica et M. arenaria au moyen de l'amplification de regions de sequences caracteristiques (SCAR) par une technique PCR - Trois marqueurs d'ADN polymorphique amplifiee au hasard (RAPD) OPA-12 420 , OPB-O6 1200 et OPA-OI 700 , respectivement specifiques des especes de nematodes Meloidogyne arenaria , M. incognita et M. javanica , ont ete identifies. Apres le sequencage de ces produits RAPD-PCR, les amorces les plus longues de 18 a 23 nucleotides ont ete choisies pour completer les sequences terminales d'ADN des fragments d'ADN. Cela a conduit a trois paires d'amorces specifiques de l'espece, utilisees pour amplifier les regions des sequences caracteristiques (SCAR). Les lots d'amorces SCAR mis au point ont ete utilises avec succes lors d'essais directs, rapides et surs pour identifier M. incognita , M. javanica et M. arenia . Les marqueurs peuvent etre amplifies a partir de l'ADN des masses d'oeufs, des juveniles de deuxieme stade ou des femelles. Cette technique d'identification specifique est donc independante des differents etats de developpement du nematode. De plus la technique SCAR-PCR a ete appliquee avec succes a l'ADN extrait du materiel vegetal infeste. Cette methode presente des potentialites d'amelioration permettant d'envisager des tests pratiques d'identification de routine, facilitant ainsi le controle de ces parasites economiquement importants.

The embryonic cell lineage of the nematode Halicephalobus gingivalis (Nematoda: Cephalobina: Panagrolaimoidea)

Abstract: This paper describes the nearly complete embryonic cell lineage of the terrestrial nematode, Halicephalobus gingivalis, up to somatic muscle contraction, resulting in the formation of 536 cells, of which 24 undergo programmed cell death. Halicephalobus gingivalis has a 94% lineage homology with both Caenorhabditis elegans and Pellioditis marina, and a fate homology of only 86% and 78%, respectively. Although H. gingivalis belongs to a different superfamily than C. elegans and P. marina, its cell lineage is remarkably consistent with them. Variations in the fate distribution of cells among the different species were only observed at the end of the cell lineage. The data presented here show that the polyclonal cell specification is much more widespread in clades 9 and 10 and is not a highly derived trait that is specifically linked to the fast development of the model organism C. elegans.