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Volume 8, Part 2 (2000)

Zheng, J., Subbotin, S.A., Waeyenberge, L. and Moens, M.

Molecular characterisation of Chinese Heterodera glycines and H. avenae populations based on RFLPs and sequences of rDNA-ITS regions

Restriction profiles and sequences of the ITS region of Chinese populations of Heterodera glycines and H. avenae are given. In H. glycines, heterogeneity was detected after restriction of the PCR product with AvaI. This is the principal identification enzyme for this species, and usually yields four fragments of 552, 478, 367 and 112 bp. Restriction of the PCR product from the Chinese H. avenae population by HinfI and Tru9I produced RFLP profiles that differentiated it from other cereal cyst nematode populations. 

Key words: Heterodera glycines, H. avenae, heterogeneity, ITS region, rDNA.

Gäbler, C., Sturhan, D., Subbotin, S.A. and Rumpenhorst, H.J.

Heterodera pratensis sp. n., a new cyst nematode of the H. avenae complex (Nematoda: Heteroderidae)

A new cyst-forming nematode belonging to the Heterodera avenae complex and specialized on grass hosts is described as H. pratensis sp. n. The species is widely distributed in grassy habitats in northern Germany and also has been found in Russia and Estonia. Heterodera pratensis sp. n. is well distinguished from the other species in the H. avenae complex by protein isoelectric focusing and ribosomal DNA-RFLPs. In its morphological characters it most closely resembles H. avenae, H. aucklandica and H. arenaria in the absence of an underbridge in the cyst cone. It is distinguished from these species by the shape and colour of the cysts, the arrangement of the bullae, and lengths of juvenile body, tail and hyaline part of tail. Diagnostic rDNA-RFLP profiles for H. pratensis sp. n., H. avenae and H. aucklandica are given.

Key words: Estonia, Germany, Heterodera aucklandica, Heterodera avenae group, IEF, ITS-rDNA, Poaceae, Russia.

Ahmad, W. and Sturhan, D.

Sphaeroamphis gen. n. (Dorylaimida: Qudsianematidae, Thorniinae) from the Azores

The dorylaim genus Sphaeroamphis gen. n. with the single species S. azoricus sp. n. is described from coastal sites of the islands Pico and Săo Jorge, Azores. The new genus is distinctive in having a continuous lip region with amalgamated lips, almost spherical amphids with small aperture, cylindrical odontostyle with wide aperture, dorylaimoid pharynx, amphidelphic gonads, short hemispherical tail and males with slender spicules and only three ventromedian supplements. The new genus is related to the genera Thornia Meyl, 1954, Thorneella Andrássy, 1960 and especially Nygolaimoides Meyl in Andrássy, 1960 in the subfamily Thorniinae, but differs in its characteristic amphids.

Key words:  Nematoda, Portugal, Sphaeroamphis azoricus sp. n.

Schmidt-Rhaesa, A.

Scanning Electron Microscopy of the anterior end of Hystrichis tricolor (Nematoda: Dioctophymida)

The anterior end of the nematode Hystrichis tricolor Dujardin, 1845 is described from observations made using Scanning Electron Microscopy (SEM). Several points made during investigations of the species by Jägerskiöld (1909) and Karmanova (1986) were confirmed. The SEM-investigation revealed a difference in the position of the second ring of cephalic sensillae that is among the anteriormost spines. The nature of two structures tentatively interpreted as amphids remains doubtful. A regular arrangement of cuticular spines on the anterior end could be observed only partially, and this probably does not represent an overlying pattern. The anteriormost spines, for example, are not arranged in any order. Several spines are deformed, detached or broken off. Observation of the detached spines revealed that they consist of a hollow cuticular sheath that is filled by an extension of the epidermis.

Key words: amphids, anterior end, cephalic sense organs, Dioctophymida, Hystrichis, SEM

Boström, S., Holovachov, O. and Susulovsky, A.

Study of Teratocephalidae (Nematoda) from the Ukraine. Description of a population of Teratocephalus de Man, 1876 with a compendium on species from the "lirellus-group"

A population of Teratocephalus cf. lirellus Anderson, 1969 from the Ukraine is described on the basis of light and scanning electron microscopy. The specimens examined differ from the original description, and other populations described as T. lirellus, mainly by having shorter body length and structure of cuticular blocks. The identity of the population is discussed in relation to current knowledge of the taxonomy and the intraspecific variability of the genus. Some populations of Teratocephalus ("lirellus-group") with cuticle annules interrupted by longitudinal incisures forming cuticular blocks are compared.

Key words: morphology, scanning electron microscopy, taxonomy, Teratocephalus lirellus.

Chen, S., Hendrickx, G. and Moens, M.

The importance of organic matter when assaying Meloidogyne chitwoodi soil populations

Methods to detect Meloidogyne chitwoodi in soil samples were compared. It was found that the organic soil fraction can constitute a large infection reservoir. Preliminary root maceration had no effect on the yield of juveniles when a cotton wool filter extraction method was used. Conversely, extracting nematodes by centrifugation, root maceration positively influenced the recovery of nematodes. The largest M. chitwoodi recovery from the organic soil and mineral soil fractions, and from unfractionated soil, was obtained using zonal centrifugation. Increasing the density of the MgSO4 solution from 1.12 to 1.22 resulted in an increased recovery of old eggs. Small root-knot nematode densities were detected most efficiently with a bioassay and zonal centrifugal extraction.

Key words: conventional centrifugation, extraction method, Meloidogyne chitwoodi, soil fraction, root maceration, zonal centrifugation.

Pan, C., Zheng, J. Zhou, X., Neilson, R. and Brown, D.J.F.

Preliminary assessment of the occurrence of longidorid and trichodorid nematodes (Nematoda: Longidoridae and Trichodoridae) in Xiamen, Fujian Province, China

A preliminary assessment was made of the occurrence of longidorid and trichodorid nematodes in the environs of Xiamen, Fujian province, China. Longidorid nematodes were present in 16 of 24 soil samples examined, with trichodorids present in two samples. The species were identified as Longidorus litchii, Xiphinema elongatum, two putative members of the X. americanum-group, and X. hunaniense, and Trichodorus pakistanensis. The results obtained provide new information on hosts and geographical occurrence of several of the species.

Key words: distribution, Longidorus, morphometrics, new hosts, Trichodorus, Xiphinema. 

Nedelchev, S. and Peneva, V.

Description of three new species of the genus Mesodorylaimus Andrássy, 1959 (Nematoda: Dorylaimidae) from Livingston Island, Antarctica, with notes on M. imperator Loof, 1975

Three new species of the genus Mesodorylaimus Andrássy, 1959 are described from Livingston Island, South Shetland Islands, Antarctica. Mesodorylaimis chipevi sp. n. is characterised by having a long body (L=1.8-2.2 mm); tail tip cylindrical, rounded; deeply folded and thick cuticle in the vulval region; M. antarcticus sp. n. by its medium body size (L=1.3-1.6 mm), lip region off set by a shallow depression, odontostyle 13-15 µm, transverse vulva, pars refringens vaginae consisting of triangular sclerotizations, tail first conoid then more or less uniformly tapering to a spicate or narrowly rounded terminus; M. masleni sp. n by its medium body size (L=1.5-1.8 mm), lip region continuous with the body outline, odontostyle 15-17  µm, vulva transverse; presence of wrinkles and folds around vulva; pars refringens vaginae consisting of two well developed triangular arcuate sclerotizations, long tail (91-117  µm), ventrally straight, dorsally convex and subcylindroid. Some additional data on M. imperator are provided. A feature common to all Antarctic species of Mesodorylaimus is the presence of ventral papillae in the anterior and posterior parts of the body. A key to the species of the genus occurring in Antarctica is provided.

Key words: Antarctica, key, Mesodorylaimus, morphology, new species.


Tsalolikhin, S.J.

Ivan Nikolayevich Filipjev (a short biography)

Whilst much has been recorded of the life and, most importantly, the scientific contribution of N.A. Cobb, regarded as the founder of Nematology in the USA, only mainly speculation and anecdotal rumor is available of I.N. Filipjev, the founder of Nematology in Russia. The reason for the relative paucity of factual information of the life of Ivan Nikolayevich Filipjev stems mainly from the fact that in 1931 he was charged as being a subversive in communist Russia, but this charge was quickly rescinded. However, in 1933 he was again charged as a counter-revolutionary, and on this occasion was found guilty and exiled to Kazakhstan. In 1937, Filipjev was again arrested and found guilty as being an "enemy of the Soviet people", thus becoming a persona non grata in his own country. From this period all books and scientific works by Filipjev were removed from Russian institutions, and he remained a persona non-grata until in 1956 the original charges against him were cancelled posthumously. Unconfirmed information suggests that Ivan Filipjev met his death, probably at the hands of a firing squad, in a concentration camp during 1940. The following provides the first biography of one of the outstanding figures in Nematology in the twentieth century.