Characterization and Sequence Variation in the rDNA Region of Six Nematode Species of the Genus Longidorus (Nematoda).

Total DNA was isolated from individual nematodes of the species Longidorus helveticus, L. macrosoma, L. arthensis, L. profundorum, L. elongatus, and L. raskii collected in Switzerland. The ITS region and D1-D2 expansion segments of the 26S rDNA were amplified and cloned. The sequences obtained were aligned in order to investigate sequence diversity and to infer the phylogenetic relationships among the six Longidorus species. D1-D2 sequences were more conserved than the ITS sequences that varied widely in primary structure and length, and no consensus was observed. Phylogenetic analyses using the neighbor-joining, maximum parsimony and maximum likelihood methods were performed with three different sequence data sets: ITS1-ITS2, 5.8S-D1-D2, and combining ITS1-ITS2+5.8S-D1-D2 sequences. All multiple alignments yielded similar basic trees supporting the existence of the six species established using morphological characters. These sequence data also provided evidence that the different regions of the rDNA are characterized by different evolution rates and by different factors associated with the generation of extreme size variation.

First Report of the Root-Knot Nematode Meloidogyne kralli in Switzerland.

The root-knot nematode Meloidogyne kralli Jepson was originally described from Carex acuta L. near the Elva River in Estonia (3). This species, which was rarely detected in Russia, Poland, and the UK, was observed on Cyperaceae hosts in very wet, sandy, peat, and silt soils (1). Although marked as a rare and unusual root-knot nematode, a wider European distribution was hypothesized, particularly for natural habitats where Cyperaceae are common (4). In October 2001, we finished the first root-knot nematode survey in Switzerland, which included a protected peat-moss area named Hüttensee near Wädenswil at 660 m altitude. Small smooth galls were observed on the roots of different Carex species. These galls contained several hatched second-stage juveniles, partly swollen juveniles, and a few swollen adult females with small egg masses. No protruding egg masses were observed outside the galls and no males were observed inside. Second-stage juveniles together with males also were isolated from adhering soil. The identification of these nematodes as M. kralli was based on female and second-stage juvenile morphology, and female malate dehydrogenase and esterase isozyme phenotypes (2,4). M. kralli is the only root-knot nematode known to parasitize Cyperaceae hosts, although this nematode has other monocotyledonous hosts, such as Hordeum vulgare L. (1). To our knowledge this is the first published report of M. kralli from the Alps. References: (1) M. W. Brzeski. Nematodes of Tylenchina in Poland and Temperate Europe. Page 242 in: Muzeum i Instytut Zoologii PAN, Warszawa, Poland, 1998. (2) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 17:6, 1985. (3) S. Jepson. Rev. Nematol. 6:239, 1983. (4) G. Karssen and T. van Hoenselaar. Nematologica 44:713, 1998.

Pressure from the lips on the teeth during speech.

Pressure on the teeth from the labial soft tissues during the articulation of a given sentence was measured in 24 children, 8 to 14 years old, with normal incisor relationships. The points of measurement were labial in the midlines between the maxillary and mandibular central incisors and between the right maxillary canine and first premolar (the modiolus point). A mouthpiece was attached to the teeth at these three positions and connected via a water-filled system to an extraoral pressure transducer. A microphone recorded the volume and speed of articulation while the activity of the lip muscles was surveyed by electromyography. The maximal pressure during pronunciation of the consonant /p/, the pressure at rest (RP), the speech posture pressure (SPP), the time pressure integral (TPI), and the mean speech pressure (MSP) during articulation were analyzed. Maximal pressure during pronunciation of /p/ and TPI were highest at the modiolus, second highest at the lower midline, and lowest at the upper midline. RP and SPP were highest at the lower midline. SPP was 2 to 3 times higher than RP, and MSP was 4 to 7 times higher than RP. The pressures during articulation recorded at the lower midline were closely correlated with those at the modiolus, with weaker correlations between the upper and lower midlines and between the upper midline and modiolus. There was a close correlation between RP and SPP. SPP, MSP, and TPI may, along with RP, contribute to the positions of the teeth.