Molecular taxonomy and phylogeny of entomopathogenic nematode species (Rhabditida: Steinernematidae) by RFLP analysis of the ITS region of the ribosomal DNA repeat unit

1997 ◽  
Vol 37 (3) ◽  
pp. 187-193 ◽  
Author(s):  
Alexander P. Reid ◽  
William M. Hominick ◽  
Bernard R. Briscoe
Gene ◽  
1982 ◽  
Vol 20 (2) ◽  
pp. 135-137 ◽  
Author(s):  
Robin A. Lockington ◽  
Graham G. Taylor ◽  
Michael Winther ◽  
Claudio Scazzocchio ◽  
R.Wayne Davies

Zootaxa ◽  
2004 ◽  
Vol 460 (1) ◽  
pp. 1 ◽  
Author(s):  
ORESTE TRIGGIANI ◽  
ZDENEK MRÁ»EK ◽  
ALEX REID

Steinernema apuliae sp. n. has been found in soil samples collected along a saltpan border habitat in southern Italy characterized by a salted silt soil. This species belongs to the long-IJ nematode group represented by Steinernema glaseri (Steiner, 1929) and Steinernema arenarium (Artyukhovsky, 1967) among others. However, it differs from these taxa in some morphometric values such as V%, H%. Females possess asymmetrical, oblique slit vulva, slant vagina and small flap in the vulval opening. These characteristics are more distinct in second generation females which is different from most other steinernematids; the vulva position is behind the mid-body about 57% to 61% of the body length. First-generation females have a conical-like tip bearing 2 to 3 papilla-like protuberances. Male mucron is absent in both generations. Lightly brown spicules have bluntly pointed tip and elongated manubrium. Third-stage infective juveniles are on average over 1000 m long; the position of the excretory pore is posterior (D% 66) and the hyaline layer is less than half the tail length (H% 41 42). Lateral fields are formed by 8 equally distributed ridges. S. apuliae differs from S. glaseri and S. arenarium and is separated by PCR-RFLP analysis of the ITS region. There were no positive cross-breedings among these species.


1995 ◽  
Vol 90 (3-4) ◽  
pp. 477-486 ◽  
Author(s):  
S. N. Raina ◽  
Y. Ogihara

Parasitology ◽  
1993 ◽  
Vol 107 (5) ◽  
pp. 529-536 ◽  
Author(s):  
A. P. Reid ◽  
W. M. Hominick

SUMMARYThe entire ribosomal DNA repeat unit of a steinernematid species (Nashes isolate) was cloned as three separate EcoR I fragments in the plasmid pUC18. An equimolar cocktail of these three clones was used to identify Steinernema species on Southern blots as each species displays its own unique restriction fragment length polymorphisms. The clones also identified two new species isolated in a soil survey of coastal regions of Britain. One of the clones (pSn4.0) can detect length heterogeneities in the rDNA repeat unit of various isolates of some of the species, particularly the most common in the United Kingdom, S. feltiae. These differences in the rDNA repeat unit length remained constant over several years for one isolate of S. feltiae, but were different for each of the geographical isolates studied to date.


2013 ◽  
Vol 66 (3) ◽  
pp. 1089-1094 ◽  
Author(s):  
Yang Liu ◽  
Laura L. Forrest ◽  
Jillian D. Bainard ◽  
Jessica M. Budke ◽  
Bernard Goffinet

1992 ◽  
Vol 22 (2) ◽  
pp. 255-263 ◽  
Author(s):  
Michael S. Bobola ◽  
Robert T. Eckert ◽  
Anita S. Klein

The frequencies of polymorphic restriction fragments for the nuclear ribosomal DNA repeat were compared for 12 provenances of red spruce (Picearubens Sarg.) and 34 provenances of black spruce (Piceamariana (Mill.) B.S.P.). Within an individual as many as five distinct ribosomal DNA repeat unit types could be distinguished. Canonical correlation analysis revealed significant variation of restriction fragment frequencies with a geographic variate comprising latitude and longitude of provenances. Geographic origins accounted for 24.7% of the variation in polymorphic restriction fragments in black spruce and 31.8% of the variation in polymorphic restriction fragments in red spruce. Discriminant analysis, using the restriction fragment frequencies for the ribosomal DNA, was used to develop a classification model for the two species. Tenfold verification of the model produced an average correct classification of 99% for black spruce and 96% for red spruce. Plots of canonical scores for the first and second canonical variâtes clearly separated red spruce from black spruce. This study presents a novel combination of restriction fragment frequency data and multivariate analysis to distinguish species that may not always be differentiated using morphological traits.


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