The genus Pararotylenchus is synonymised with Rotylenchus and the species previously in the former are transferred to the latter. This transfer requires the change of specific epithet of R. brevicaudatus Colbran, 1962, which is preoccupied by R. brevicaudatus (Hopper, 1959) comb. n., for which R. colbrani nom. n. is proposed.
{"title":"Synonymisation of Rotylenchus Filipjev, 1936 and Pararotylenchus Baldwin & Bell, 1981 (Nematoda: Hoplolaimidae)","authors":"M. Brzeski, Y. Choi","doi":"10.1163/005225998X00055","DOIUrl":"https://doi.org/10.1163/005225998X00055","url":null,"abstract":"The genus Pararotylenchus is synonymised with Rotylenchus and the species previously in the former are transferred to the latter. This transfer requires the change of specific epithet of R. brevicaudatus Colbran, 1962, which is preoccupied by R. brevicaudatus (Hopper, 1959) comb. n., for which R. colbrani nom. n. is proposed.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74694550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Changes in chitinase activity were observed following infection of three potato clones (12380, P55/7 and Maris Piper) with four pathotypes of the potato cyst nematodes, Globodera rostochiensis and G. pallida. Following invasion, the intercellular fluid of the leaves of all the plants tested showed marked increases in exochitinase activity. In contrast, after removal of intercellular fluid the leaf homogenates showed only a limited increase in endochitinase activity. In roots, endochitinases were significantly increased in 12380 following invasion by G. pallida Pal and G. rostochiensis Ro1 and Ro5 but not by G. pallida Pa2/3. The largest increase in exochitinase activity in the roots of 12380 was observed after invasion by G. pallida Pa1. The possible role of these chitinases in potato-nematode interactions is discussed.
{"title":"Detection of Chitinases in Potato Plants Following Infection With the Potato Cyst Nematodes, Globodera Rostochiensis and G. Pallida","authors":"S. Rahimi, R. Perry, D. Wright","doi":"10.1163/005325998X00063","DOIUrl":"https://doi.org/10.1163/005325998X00063","url":null,"abstract":"Changes in chitinase activity were observed following infection of three potato clones (12380, P55/7 and Maris Piper) with four pathotypes of the potato cyst nematodes, Globodera rostochiensis and G. pallida. Following invasion, the intercellular fluid of the leaves of all the plants tested showed marked increases in exochitinase activity. In contrast, after removal of intercellular fluid the leaf homogenates showed only a limited increase in endochitinase activity. In roots, endochitinases were significantly increased in 12380 following invasion by G. pallida Pal and G. rostochiensis Ro1 and Ro5 but not by G. pallida Pa2/3. The largest increase in exochitinase activity in the roots of 12380 was observed after invasion by G. pallida Pa1. The possible role of these chitinases in potato-nematode interactions is discussed.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72694310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evidence for a sex pheromone in Steinemema carpocapsae","authors":"J. Neves, N. Simões, M. Mota","doi":"10.1163/005225998X00109","DOIUrl":"https://doi.org/10.1163/005225998X00109","url":null,"abstract":"","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80937563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The root-knot nematode, Meloidogyne maritima, a parasite of marram grass (Ammophila arenaria), is redescribed from the type locality, a coastal dune near Perranporth, UK. This species is characterized by second-stage juvenile 471 μm long, hemizonid posterior to excretory pore, tail 71.5 μm long, hyaline tail terminus indistinct; male head tapering, not set off, labial disc elevated, rounded and fused with crescent shaped medial lips, lateral lips present, stylet 20.5 μm long, with relatively small rounded knobs, slightly sloping backwardly, lateral field areolated; female stylet curved dorsally, 14.2 μm long, with rounded to transversely ovoid shaped knobs, slightly sloping backwardly, excretory pore located near level of stylet knobs, perineal pattern relatively small, rounded to ovoid and dorsal arch low with lateral field distinct. A malate dehydrogenase pattern, N1a type, and a VS1-S1type of esterase isozyme pattern were detected. Meloidogyne duytsi Karssen et al., 1998, was found on Elymus furctus in the foredunes of the type locality.
{"title":"Redescription of the root-knot nematode Meloidogyne maritima Jepson, 1987 (Nematoda: Heteroderidae), a parasite of Ammophila arenaria (L.) Link.","authors":"G. Karssen, A. V. Aelst, R. Cook","doi":"10.1163/005425998X00026","DOIUrl":"https://doi.org/10.1163/005425998X00026","url":null,"abstract":"The root-knot nematode, Meloidogyne maritima, a parasite of marram grass (Ammophila arenaria), is redescribed from the type locality, a coastal dune near Perranporth, UK. This species is characterized by second-stage juvenile 471 μm long, hemizonid posterior to excretory pore, tail 71.5 μm long, hyaline tail terminus indistinct; male head tapering, not set off, labial disc elevated, rounded and fused with crescent shaped medial lips, lateral lips present, stylet 20.5 μm long, with relatively small rounded knobs, slightly sloping backwardly, lateral field areolated; female stylet curved dorsally, 14.2 μm long, with rounded to transversely ovoid shaped knobs, slightly sloping backwardly, excretory pore located near level of stylet knobs, perineal pattern relatively small, rounded to ovoid and dorsal arch low with lateral field distinct. A malate dehydrogenase pattern, N1a type, and a VS1-S1type of esterase isozyme pattern were detected. Meloidogyne duytsi Karssen et al., 1998, was found on Elymus furctus in the foredunes of the type locality.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87504569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The spatial distributions of three nematode species (Longidorus elongatus, Longidorus goodeyi and Rotylenchus goodeyi) were intensively sampled in a permanent pasture field. Three regular sampling grids were employed covering scales ranging from 5 cm to 50 m. Geostatistical analyses were used to quantify any spatial dependencies found within and between nematode species. All three species were present in most samples and in general the raw counts were positively skewed. Semivariograms of transformed counts (log 10 (counts + 1)), showed similar, generally isotropic, trends for all three species with the variance increasing with separation distance. There was no evidence of a sill i.e. a levelling off of variance at larger scales. The only inter-species correlations detected were at scales up to about 20 cm between L. elongatus and L. goodeyi, species which share a similar environmental niche. A power model provided the best description of the semivariograms and is discussed in relation to "fractional Brownian motion", a scaling property present in many natural systems.
{"title":"A Comparison of the Spatial Distributions of Three Plant-Parasitic Nematode Species At Three Different Scales","authors":"B. Marshall, B. Boag, J. McNicol, R. Neilson","doi":"10.1163/005425998X00062","DOIUrl":"https://doi.org/10.1163/005425998X00062","url":null,"abstract":"The spatial distributions of three nematode species (Longidorus elongatus, Longidorus goodeyi and Rotylenchus goodeyi) were intensively sampled in a permanent pasture field. Three regular sampling grids were employed covering scales ranging from 5 cm to 50 m. Geostatistical analyses were used to quantify any spatial dependencies found within and between nematode species. All three species were present in most samples and in general the raw counts were positively skewed. Semivariograms of transformed counts (log 10 (counts + 1)), showed similar, generally isotropic, trends for all three species with the variance increasing with separation distance. There was no evidence of a sill i.e. a levelling off of variance at larger scales. The only inter-species correlations detected were at scales up to about 20 cm between L. elongatus and L. goodeyi, species which share a similar environmental niche. A power model provided the best description of the semivariograms and is discussed in relation to \"fractional Brownian motion\", a scaling property present in many natural systems.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85359769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
European populations of Globodera pallida (ten from the UK, two from Iceland, one from the Netherlands) and G. rostochiensis (nine from the UK, two from Italy and one each from Germany, Iceland and the Netherlands) and a Bolivian population of the latter species were reared on three commercial potato cultivars and five differential potato clones. Using Principal Component Analysis and the results of two Hierarchical Cluster Analyses, even populations from the same place (e.g. two from the same farm at Woburn and two from Feltwell) were shown to differ in virulence. Differences were also found between a population selected on potato clone Solanum vernei (VT n)2 62.33.3 and its unselected parent population (Cadishead). Cultivar Morag is partially resistant to G. rn.stochiensis but showed less resistance to G. pallida than reported previously. The virulence bioassay clearly distinguished the two PCN species but failed to classify populations into 'pathotypes'. The arbitrarily designated Pf/Pi value of 1.5 was not necessarily appropriate for distinguishing virulent from avirulent populations. Since virulence appears to be very much a quantitative biological trait (particularly with respect to G. pallida populations), and therefore impossible to classify in a scheme with the logical alternatives of false (does not reproduce) or true (reproduces), its value as a concept probably resides in the future design of decision making software for forecasting population development based on recorded Pf/Pi values.
{"title":"Virulence of Populations of Potato Cyst Nematodes (Globodera Spp.) From Europe and Bolivia Towards Differential Potato Clones Frequently Used for Pathotype Classification","authors":"I. F. Bendezu, M. Russell, K. Evans","doi":"10.1163/005725998X00078","DOIUrl":"https://doi.org/10.1163/005725998X00078","url":null,"abstract":"European populations of Globodera pallida (ten from the UK, two from Iceland, one from the Netherlands) and G. rostochiensis (nine from the UK, two from Italy and one each from Germany, Iceland and the Netherlands) and a Bolivian population of the latter species were reared on three commercial potato cultivars and five differential potato clones. Using Principal Component Analysis and the results of two Hierarchical Cluster Analyses, even populations from the same place (e.g. two from the same farm at Woburn and two from Feltwell) were shown to differ in virulence. Differences were also found between a population selected on potato clone Solanum vernei (VT n)2 62.33.3 and its unselected parent population (Cadishead). Cultivar Morag is partially resistant to G. rn.stochiensis but showed less resistance to G. pallida than reported previously. The virulence bioassay clearly distinguished the two PCN species but failed to classify populations into 'pathotypes'. The arbitrarily designated Pf/Pi value of 1.5 was not necessarily appropriate for distinguishing virulent from avirulent populations. Since virulence appears to be very much a quantitative biological trait (particularly with respect to G. pallida populations), and therefore impossible to classify in a scheme with the logical alternatives of false (does not reproduce) or true (reproduces), its value as a concept probably resides in the future design of decision making software for forecasting population development based on recorded Pf/Pi values.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90740154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A series of sub-populations was produced from a population of Globodera pallida by raising single cyst progenies on three susceptible potato cultivars. After completion of each generation, single cysts were taken to produce the next generation. Six generations were completed and then the resulting sub-populations were multiplied on the susceptible cultivar Ddsir6e. A sample of these sub-populations was then used to conduct a virulence test and to investigate the genetic variation among the sub-populations. The virulence test showed that the susceptible cultivar used in the generation of these sub-populations had a marked effect on the general reproductive capability of the sub-populations and that there was a range of variation in virulence on partially resistant clones. A RAPD study revealed that the range of genetic variation among these sub-populations was comparable to that shown between field populations in other studies and that there was a tendency for the sub-populations to be grouped in relation to the susceptible cultivar they were reared on. These results from an artificially fragmented population are discussed in relation to the introduction and spread of potato cyst nematodes in Europe.
{"title":"Studies On an Artificially Fragmented Population of Potato Cyst Nematode Globodera Pallida","authors":"M. Phillips, V. Blok, A. Ploeg, B. Harrower","doi":"10.1163/005725998X00069","DOIUrl":"https://doi.org/10.1163/005725998X00069","url":null,"abstract":"A series of sub-populations was produced from a population of Globodera pallida by raising single cyst progenies on three susceptible potato cultivars. After completion of each generation, single cysts were taken to produce the next generation. Six generations were completed and then the resulting sub-populations were multiplied on the susceptible cultivar Ddsir6e. A sample of these sub-populations was then used to conduct a virulence test and to investigate the genetic variation among the sub-populations. The virulence test showed that the susceptible cultivar used in the generation of these sub-populations had a marked effect on the general reproductive capability of the sub-populations and that there was a range of variation in virulence on partially resistant clones. A RAPD study revealed that the range of genetic variation among these sub-populations was comparable to that shown between field populations in other studies and that there was a tendency for the sub-populations to be grouped in relation to the susceptible cultivar they were reared on. These results from an artificially fragmented population are discussed in relation to the introduction and spread of potato cyst nematodes in Europe.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74043582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Up to 16 fatty acids were detected in total lipids from roots and leaves of two potato cultivars, Desiree and Maris Piper, and one tomato cultivar, Pixie. The fatty acid profiles from roots were similar for all three cultivars and were dominated by C18 : 2 (30-40%) and C 16 : 0 (about 22%). The fatty acid profiles from leaves were similar for all three cultivars and were dominated by C18 : 3 (about 52%). Both root and leaf lipids contained mainly C18 fatty acids. The lipid content found in dry cysts of Globodera rostochiensis rcared on different cultivars was 11.0%, 12.8% and 9.6% for potato cvs Desiree and Foremost and tomato cv. Pixie, respectively. The total lipid comprised 74-82% neutral lipid, 14-19% non-acidic phospholipid and 4-7% free fatty acid in the three samples. Hatched juveniles (J2) from cysts cultured on cvs Desiree and Foremost contained 26.1% and 24.3% lipid, respectively. The total lipid comprised 77% neutral lipid, 17-18% non-acidic phospholipid and 6-7% free fatty acid in the two samples. The fatty acid profiles of the main lipid classes of cysts of G. rostochiensis cultured on the three different cultivars were similar. The fatty acid composition of the main lipid classes of freshly hatched J2 from cysts of G. rostochiensis cultured on the two potato cultivars differed only in their free fatty acid fractions. A comparison of the fatty acid profiles of the total lipid of potato roots, cv. Desiree, and the total lipid of cysts of G. rostochiensis showed major differences. Root fatty acids and nematode fatty acids were 38% and 22% saturated, 10% and 44% monounsaturated and 52% and 35% polyunsaturated, respectively. The fatty acid profile of root lipids was dominated by C16: 0, C18: 2 and C18 : 3 but the nematode lipids consisted of mainly C18: 1, C20: 1 and C20: 4. The differences in the fatty acids of host and nematodes indicate that G. rostochiensis is capable of fatty acid chain elongation and/or desaturation.
{"title":"The Influence of the Host Plant On Lipid Reserves of Globodera Rostochiensis","authors":"R. A. Holz, D. Wright, R. Perry","doi":"10.1163/005325998X00045","DOIUrl":"https://doi.org/10.1163/005325998X00045","url":null,"abstract":"Up to 16 fatty acids were detected in total lipids from roots and leaves of two potato cultivars, Desiree and Maris Piper, and one tomato cultivar, Pixie. The fatty acid profiles from roots were similar for all three cultivars and were dominated by C18 : 2 (30-40%) and C 16 : 0 (about 22%). The fatty acid profiles from leaves were similar for all three cultivars and were dominated by C18 : 3 (about 52%). Both root and leaf lipids contained mainly C18 fatty acids. The lipid content found in dry cysts of Globodera rostochiensis rcared on different cultivars was 11.0%, 12.8% and 9.6% for potato cvs Desiree and Foremost and tomato cv. Pixie, respectively. The total lipid comprised 74-82% neutral lipid, 14-19% non-acidic phospholipid and 4-7% free fatty acid in the three samples. Hatched juveniles (J2) from cysts cultured on cvs Desiree and Foremost contained 26.1% and 24.3% lipid, respectively. The total lipid comprised 77% neutral lipid, 17-18% non-acidic phospholipid and 6-7% free fatty acid in the two samples. The fatty acid profiles of the main lipid classes of cysts of G. rostochiensis cultured on the three different cultivars were similar. The fatty acid composition of the main lipid classes of freshly hatched J2 from cysts of G. rostochiensis cultured on the two potato cultivars differed only in their free fatty acid fractions. A comparison of the fatty acid profiles of the total lipid of potato roots, cv. Desiree, and the total lipid of cysts of G. rostochiensis showed major differences. Root fatty acids and nematode fatty acids were 38% and 22% saturated, 10% and 44% monounsaturated and 52% and 35% polyunsaturated, respectively. The fatty acid profile of root lipids was dominated by C16: 0, C18: 2 and C18 : 3 but the nematode lipids consisted of mainly C18: 1, C20: 1 and C20: 4. The differences in the fatty acids of host and nematodes indicate that G. rostochiensis is capable of fatty acid chain elongation and/or desaturation.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84576869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Investigations on the occurrence of Bursaphelenchus nematodes were carried out in damaged coniferous forests in Germany during the summer and autumn, 1996. The survey was part of a joint research project supported by the Commission of the European Communities (FAIR programme) aiming at the evaluation of the importance of Bursaphelenchus nematodes in South East and Central Europe. During this survey a new species, Bursaphelenchus hofmanni, was found in spruce wood in Thuringia, Germany. The species is characterized by a relatively small body length, females and males averaging 578 and 530 μm, respectively, the a-value in females and males 28 (23-31) and 25 (22-31), respectively, with a stylet length of 12 (11-14) μm. The males have relatively small and slightly curved spicules (length 13 [11-17] μm) with a prominent rostrum and a small cucullus.The female tail is conoid and curved with a finely rounded terminus. The females have a small vulval flap.
{"title":"Bursaphelenchus hofmanni sp. n. (Nematoda, Aphelenchoididae) from spruce wood in Germany.","authors":"H. Braasch","doi":"10.1163/005725998X00023","DOIUrl":"https://doi.org/10.1163/005725998X00023","url":null,"abstract":"Investigations on the occurrence of Bursaphelenchus nematodes were carried out in damaged coniferous forests in Germany during the summer and autumn, 1996. The survey was part of a joint research project supported by the Commission of the European Communities (FAIR programme) aiming at the evaluation of the importance of Bursaphelenchus nematodes in South East and Central Europe. During this survey a new species, Bursaphelenchus hofmanni, was found in spruce wood in Thuringia, Germany. The species is characterized by a relatively small body length, females and males averaging 578 and 530 μm, respectively, the a-value in females and males 28 (23-31) and 25 (22-31), respectively, with a stylet length of 12 (11-14) μm. The males have relatively small and slightly curved spicules (length 13 [11-17] μm) with a prominent rostrum and a small cucullus.The female tail is conoid and curved with a finely rounded terminus. The females have a small vulval flap.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82011802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A method is described for the production of bacteria-free Heterorhabditis bacteriophora and H. indica dauer juveniles by culturing these nematodes on Photorhabdus luminescens symbionts isolated from H. megidis and from H. bacteriophora, respectively. The nematodes develop and reproduce, feeding on the bacterial cells, but the symbionts are not retained by the dauer juveniles. Through surface sterilisation of the resulting dauer juveniles, axenic dauer juveniles could be produced, which were used for compatibility tests. The tests showed that H. bacteriophora did not reproduce on the symbionts of H. indica and that H. indica did not reproduce on the symbiont isolated from an undescribed Heterorhabditis species (Q6). Dauer juveniles of Heterorhabditis species start development (recover) in response to food signals excreted into the culture by P. luminescens. The recovery inducing signal may be produced by strains on which the nematode cannot reproduce. In cultures of such incompatible bacterial strains, developing dauer juveniles take up the bacteria in the intestine but die after 3 days, probably because they lack the enzymes needed to digest the bacterial cells. Food signals produced by Xenorhabdus species, the symbionts of Steinernema species, do not induce recovery of H. bacteriophora. Currently, bacteria isolated from different Heterorhabditis species are all assigned to the species P. luminescens. The specificity of the nutritive function supports the subdivision of the taxon P. luminescens into several species.
{"title":"Cultivation of axenic Heterorhabditis spp. dauer juveniles and their response to non-specific Photorhabdus luminescens food signals","authors":"R. Ehlers, R. Han","doi":"10.1163/005525998X00089","DOIUrl":"https://doi.org/10.1163/005525998X00089","url":null,"abstract":"A method is described for the production of bacteria-free Heterorhabditis bacteriophora and H. indica dauer juveniles by culturing these nematodes on Photorhabdus luminescens symbionts isolated from H. megidis and from H. bacteriophora, respectively. The nematodes develop and reproduce, feeding on the bacterial cells, but the symbionts are not retained by the dauer juveniles. Through surface sterilisation of the resulting dauer juveniles, axenic dauer juveniles could be produced, which were used for compatibility tests. The tests showed that H. bacteriophora did not reproduce on the symbionts of H. indica and that H. indica did not reproduce on the symbiont isolated from an undescribed Heterorhabditis species (Q6). Dauer juveniles of Heterorhabditis species start development (recover) in response to food signals excreted into the culture by P. luminescens. The recovery inducing signal may be produced by strains on which the nematode cannot reproduce. In cultures of such incompatible bacterial strains, developing dauer juveniles take up the bacteria in the intestine but die after 3 days, probably because they lack the enzymes needed to digest the bacterial cells. Food signals produced by Xenorhabdus species, the symbionts of Steinernema species, do not induce recovery of H. bacteriophora. Currently, bacteria isolated from different Heterorhabditis species are all assigned to the species P. luminescens. The specificity of the nutritive function supports the subdivision of the taxon P. luminescens into several species.","PeriodicalId":18988,"journal":{"name":"Nematologica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81292468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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