Edward Platzer - Academia.edu (original) (raw)
Papers by Edward Platzer
Journal of Parasitology, 2001
Otostrongylus circumlitus (Railliet, 1899) from Pacific harbor seals (Phoca vitulina richardsi) a... more Otostrongylus circumlitus (Railliet, 1899) from Pacific harbor seals (Phoca vitulina richardsi) and northern elephant seals (Mirounga angustirostris) were examined using morphological and molecular methods to determine whether northern elephant seals along the central California coast are infected by the same species of Otostrongylus as are Pacific harbor seals in the same area. Fixed nematodes were examined and measured using light microscopy. The polymerase chain reaction (PCR) was used to amplify and sequence the second internal transcribed spacer (ITS-2) and D3 expansion (26S) regions of ribosomal DNA of O. circumlitus from Pacific harbor and northern elephant seals. The ITS-2 region was also amplified from Parafilaroides sp. from the Pacific harbor seal, northern elephant seal, and California sea lion (Zalophus californianus) and used for restriction fragment length polymorphism (RFLP) analysis. Morphologically, it was not possible to distinguish O. circumlitus from Pacific harbor and northern elephant seals, and over a consensus length of 443 base pairs (bp) for ITS-2 and 321 bp for D3 the sequences of O. circumlitus from both hosts were identical. With the PCR-RFLP assay, it was possible to distinguish O. circumlitus from Parafilaroides sp. The results suggest that O. circumlitus is the same species in Pacific harbor and northern elephant seals, and molecular methods make it possible to distinguish this nematode from related nematodes.
Nematology, 2007
Interactions of the mermithid nematode Romanomermis culicivorax with the immune system of mosquit... more Interactions of the mermithid nematode Romanomermis culicivorax with the immune system of mosquito larvae were examined by scanning electron microscopy. The host immune system rapidly recognised invading parasites, as granulocytes and discharged granules were observed attached to parasitic nematodes within 5 min. Melanin deposition was infrequently observed. As a counter measure, the parasites secreted and shed an extracellular surface coat which aided immune evasion. During the first 4 days of infection, when parasite growth was limited, the coat served as a disposable, renewable barrier between parasite and host that was intermittently shed to cleanse the nematode of adhering host immune products. In the later infection phase the parasite grew rapidly and was beyond the effect of the depleted host immune response. The broad host range of R. culcivorax within culicines may be partly a function of the nonspecific defence it mounts against the host immune system. In summary, shedding...
Biotechniques, Mar 1, 1991
J Invertebr Pathol, 1980
ABSTRACT
Comparative biochemistry and physiology. B, Comparative biochemistry, Jan 15, 1974
Dihydrofolate reductase, formyl tetrahydrofolate synthetase and methylene tetrahydrofolate dehydr... more Dihydrofolate reductase, formyl tetrahydrofolate synthetase and methylene tetrahydrofolate dehydrogenase were compared in Aphelenchus avenae and Nippostrongylus brasiliensis. 2. Dihydrofolate reductase activity was highest in N. brasiliensis. 3. Methylene THF dehydrogenase activity was similar in both species. 4. Formyl THF synthetase activity was highest in the infective larvae of N. brasiliensis. 5. Formyl THF synthetase was partially purified from A. avenae and N. brasiliensis. 6. The K~ for tetrahydrofolate was lower for formyl THF synthetase from A. avenae but the Km's for ATP and formate were similar for the enzyme in both nematodes.
Hua xi yi ke da xue xue bao = Journal of West China University of Medical Sciences = Huaxi yike daxue xuebao / [bian ji zhe, Hua xi yi ke da xue xue bao bian wei hui], 1992
A new species of Mermithidae was found parasitizing the larvae of Culex tritaeniorhynchus and Cul... more A new species of Mermithidae was found parasitizing the larvae of Culex tritaeniorhynchus and Culex fatigans in Henan, China and then named Romanomermis yunanensis. Thirty-one species of Mosquitoes involving six genera have been tested for susceptibility to R. yunanensis and Culicinae mosquito have consistently been highly susceptible. At a 1:5 ratio of mosquito larvae to nematode juveniles, the parasitisms of Aedes aegypti, Ae. albopictus, Culex fatigans, Culex tritaeniorhynchus, Anopheles sinensts, Psorophora columbiae and Culesta inornata were 98.2%, 98.5%, 98.6%, 97.1%, 0%, 98.8%, and 99.0% respectively. R. yunanensis presented a phenomenon of retarted development in Anopheles maculatus, which remained at the parasitic stage both in the larvae and pupa of An. maculatus. The parasitism of An. dirus was 89.7%, but most (88.8%) parasitizing mermithids underwent melanization and died. The comparative susceptibility of some North American mosquitoes to R. yunanesis and R. culicivorax...
Subcellular fractions of the bird malaria, Plasmodium lophurae , were prepared by differential ce... more Subcellular fractions of the bird malaria, Plasmodium lophurae , were prepared by differential centrifugation. Cytochrome oxidase activity was located in the mitochondrial fraction. A major portion of glutamate dehydrogenase activity was found in the mitochondrial fraction with the remainder in the ribosomal and cytosolic fractions. Malate dehydrogenase and serine hydroxymethyltranaferase activities were located primarily in the cytosolic fraction .
Background. The mermithid nematode Romanomermis iyengari is one of several natural control altern... more Background. The mermithid nematode Romanomermis iyengari is one of several natural control alternatives to synthetic pesticides for mosquito suppression. The commonly used mass rearing procedure of R. iyengari involves the use of coarse sand as a substrate for nematode maturation and oviposition. The coarse sand technique gives excellent nematode productivity in North America. However, under West African climatic conditions, this technique generates relatively lesser amounts of infectious worms. We evaluated coconut coir fibres as a replacement for coarse sand to improve yields in largescale production of R. iyengari in Benin, West Africa. Materials and Methods. Culex quinquefasciatus was the host for the nematodes, and mosquitoes were blood-fed on chickens. Four days after blood feeding, egg rafts were collected and transferred into trays, each containing 2 l of water. The mosquito larvae were fed with fish food. When the mosquito larvae reached the second instar, preparasites (J2) were added (3 J2/larva) to the incubation trays. Eight days after infection, post-parasitic juveniles were separated from the water containing dead mosquito larvae and other debris using sieves and needles; 2 g of them were deposited in containers with coarse sand or coconut coir fibres and water. Three hours later, the water was drained, the jars covered and stored for eight weeks, after which J2 abundance was determined, using a total of 320 containers for each substrate. The abundance of J2 preparasites was also assessed 3-5 months after storage to determine the impact of long-term storage on the J2 yield. Results. After 2 months storage, 2 g of post-parasites (~457 females and 583 males) yielded an average of 559,300±6094 J2 and 155,818±4427 J2 per container for coconut fibres and for coarse sand, respectively. During long-term storage, yields of J2 on coconut fibres substrate slowly decreased from 442,180±9322 J2 (3 months storage) to 163,632±12,416 J2 per container (5 months storage). On coarse sand substrate, the yield was relatively low and decreased from 49,812±1200 J2 at 3 months storage to 3046±229 J2 at 5 months storage. Conclusion. Under West African climatic conditions, coconut coir fibres gave significantly higher preparasitic nematode yields than the coarse sand technique.
Journal of Invertebrate Pathology, Aug 1, 1986
The energy status of Rorncrnorrzrr-/nis c,rt/ic,i,,o,.a.r-parasitized and control CltlcJ.tpipietl... more The energy status of Rorncrnorrzrr-/nis c,rt/ic,i,,o,.a.r-parasitized and control CltlcJ.tpipietls larvae was studied in vivo with jlP nuclear magnetic resonance (NMR) at 4-6°C. Peak assignments were made for inorganic phosphorus, phosphoarginine. AMP, ADP. and ATP. The mean ATPiADP ratios were 4.45 for control and 4.02 and 2.94 for parasitized mosquito larvae with I .3 and 2.3 parasites per host, respectively. The ATPiADP ratios for control mosquito larvae reared with a pH of 7 and 4.5 were not significantly different. R. ctrlici\wtrx parasitism had no significant effect on the ATP level in whole mosquito larvae. The mean ATP concentrations were 9.86 and I I .64 nmolimg dry weight mosquito for control and parasitized larvae. respectively. R. c~rrlici~wrcrx postparasites t IO days post-infection) were shown to have a very weak 31P NMR signal and it was concluded that the parasites contribute little to the NMR spectra of infected mosquito larvae. Enzymatic analysis of perchloric acid-extracted control mosquito larvae yielded 9.3 nmol ATPimg dry wt and 2.6 nmol ATPimg dry weight for R. ctrlicirwux postparasites at IO days post-infection. I 19x6 Academ>c PX\\. Inc.
Magnetic Resonance in Medicine, Nov 1, 1990
3'P NMR spectroscopy of a parasitic nematode, Sfeinernema caryocaysue, is described.
Comparative Biochemistry and Physiology a Comparative Physiology, Feb 1, 1984
l.
Proceedings of the National Academy of Sciences of the United States of America, Mar 4, 2003
Bacillus thuringiensis (Bt) crystal proteins are pore-forming toxins used as insecticides around ... more Bacillus thuringiensis (Bt) crystal proteins are pore-forming toxins used as insecticides around the world. Previously, the extent to which these proteins might also target the invertebrate phylum Nematoda has been mostly ignored. We have expressed seven different crystal toxin proteins from two largely unstudied Bt crystal protein subfamilies. By assaying their toxicity on diverse free-living nematode species, we demonstrate that four of these crystal proteins are active against multiple nematode species and that each nematode species tested is susceptible to at least one toxin. We also demonstrate that a rat intestinal nematode is susceptible to some of the nematicidal crystal proteins, indicating these may hold promise in controlling vertebrate-parasitic nematodes. Toxicity in nematodes correlates with damage to the intestine, consistent with the mechanism of crystal toxin action in insects. Structure-function analyses indicate that one novel nematicidal crystal protein can be engineered to a small 43-kDa active core. These data demonstrate that at least two Bt crystal protein subfamilies contain nematicidal toxins.
Cellular Immunology, Mar 31, 1989
To investigate whether the formation of IgE is linked in vivo to an IgG subclass, mice were infec... more To investigate whether the formation of IgE is linked in vivo to an IgG subclass, mice were infected with four helminth parasites, Nippostrongylus brasiliensis (Nbr), Mesocestoides corti, Taenia crassiceps and Trichinella spiralis, and the changes in the serum levels of the different Ig isotypes as well as the antibody response to M. corti and T. crassiceps antigen extracts were determined by radioimmunoassays. All four parasites induced a concomitant increase of the IgE and IgGl serum levels and usually a decrease of the IgG2a level. They also induced an increase of the IgM level but had little effect on the IgGZb, IgG3, and IgA serum levels. The specific antibodies to an M. corti antigen extract were mainly of the IgGl subclass, whereas it was of both IgGl and IgG2a subclasses to T. crassiceps. Injections of dead M. corti induced an increase of all IgG subclasses and similar levels of IgGl and IgG2a anti-parasite antibodies. Subcutaneous instead of intraperitoneal infection with T. crassiceps induced higher IgG2a than IgGl levels and lo-fold lower IgE levels than the natural ip infection; however, despite the greater IgG2a polyclonal response, anti-parasite antibodies were predominantly of the IgGl subclass. The data demonstrate that natural infection with four different helminth parasites induces a concomitant polyclonal IgGl and IgE response. These in vivo observations corroborate the recent in vitro findings demonstrating that interleukin-4 induces lipopolysaccharideactivated murine B cells to secrete both IgGl and IgB, suggesting that the regulation of these two isotypes is linked.
Journal of Nematology, Aug 1, 1985
Uhrastructural study of the body wall of preparasitic, parasitic, and postparasitic stages of Rom... more Uhrastructural study of the body wall of preparasitic, parasitic, and postparasitic stages of Romanomermis culicivorax showed that the cuticle of all three stages was permeable to lanthanum.
Comparative Biochemistry and Physiology, 1970
ABSTRACT
Insect Biochemistry, 1984
Tricarboxylic acid cycle intermediates in the haemolymph of healthy and infected larvae of Culex ... more Tricarboxylic acid cycle intermediates in the haemolymph of healthy and infected larvae of Culex pipiens, Aedes taeniorhynchus and Anopheles quadrimaculatus were determined by enzymatic analyses and gas-chromatographic procedures. Pyruvate increased by over 100~o in C. pipiens late fourth stage healthy larvae compared with early fourth stage larvae and a-ketoglutarate contents were reduced in the late fourth stage larvae of all three species. Malate was the predominant haemolymph acid with appreciable amounts of citrate and lactate. Haemolymph from larvae infected with Romanomermis culicivorax, compared with that from healthy larvae of C. pipiens and A. taeniorhynchus showed no change in succinate, but fumarate, malate and citrate concentrations were higher. Lactate and ~-ketoglutarate concentrations were elevated in A. taeniorhynchus but remained unchanged in the other two species. Oxaloacetate was reduced to undetectable levels in C. pipiens and A. taeniorhynchus infected larvae. Lactate, succinate, malate, oxaloacetate and fumarate remained unchanged between healthy and infected A. quadrimaculatus larvae, but citrate and pyruvate were reduced. Pyruvate concentration was also reduced in C. pipiens infected larvae, but remained constant in A. taeniorhynchus.
Insect Biochemistry, 1984
A method is described for the quantitative analysis of some components of the tricarboxylic acid ... more A method is described for the quantitative analysis of some components of the tricarboxylic acid cycle in microsamples (25/~1) of insect haemolymph. The method involves purification using ion-exchange chromatography, followed by gas chromatography of the acids as their trimethylsilyl derivatives. Particular attention has been paid to the treatment of ion-exchange resin before addition of sample and to methods of drying prior to derivatization to minimize losses. The effects of deproteinization on haemolymph acid content were studied using [~4C]citric acid and oleic acid. Results are presented for studies completed on the haemolymph of the fourth stage larvae of the mosquito Culex pipiens. Malic acid constituted the major component of the TCA cycle acid metabolites, with appreciable quantities of lactic and citric acids. Succinic and fumaric acids were also present.
International Journal For Parasitology, Sep 30, 1988
A method for surface sterilization of large numbers (> 5 000) of preparasites of Romanomermis cul... more A method for surface sterilization of large numbers (> 5 000) of preparasites of Romanomermis culicivorax is presented. Grace's insect tissue culture medium (GITC) was supplemented with fetal bovine serum and bovine albumin and used as a basal test medium (BB) for in vitro culture attempts with R. culicivorax preparasites. Experiments were run in 1 ml of test media in sealed glass tubes for 21 days at 27 f 1' at densities of about 146 parasitesltube. Various modifications of the test medium were evaluated. The mean growth of R. culicivorax was measured with the Bradford protein assay and compared to a growth equation attained in vivo. One of the best media rested was GITC medium with the Salt concentrations altered to that reported for the hemolymph of fourth instars of Culex pipiens, the amino acid concentrations based on hydrolyzed female R. culcivorax postparasites, and reduced glutathione (200 mg/l) was added (RCg). Average growth in this medium was 944.4 ng proteinlparasite which was equivalent to 4.2 days growth in vivo. A significant decrease in growth (P < 0.05) was noted when parasite densities per tube were
Journal of Parasitology, 2001
Otostrongylus circumlitus (Railliet, 1899) from Pacific harbor seals (Phoca vitulina richardsi) a... more Otostrongylus circumlitus (Railliet, 1899) from Pacific harbor seals (Phoca vitulina richardsi) and northern elephant seals (Mirounga angustirostris) were examined using morphological and molecular methods to determine whether northern elephant seals along the central California coast are infected by the same species of Otostrongylus as are Pacific harbor seals in the same area. Fixed nematodes were examined and measured using light microscopy. The polymerase chain reaction (PCR) was used to amplify and sequence the second internal transcribed spacer (ITS-2) and D3 expansion (26S) regions of ribosomal DNA of O. circumlitus from Pacific harbor and northern elephant seals. The ITS-2 region was also amplified from Parafilaroides sp. from the Pacific harbor seal, northern elephant seal, and California sea lion (Zalophus californianus) and used for restriction fragment length polymorphism (RFLP) analysis. Morphologically, it was not possible to distinguish O. circumlitus from Pacific harbor and northern elephant seals, and over a consensus length of 443 base pairs (bp) for ITS-2 and 321 bp for D3 the sequences of O. circumlitus from both hosts were identical. With the PCR-RFLP assay, it was possible to distinguish O. circumlitus from Parafilaroides sp. The results suggest that O. circumlitus is the same species in Pacific harbor and northern elephant seals, and molecular methods make it possible to distinguish this nematode from related nematodes.
Nematology, 2007
Interactions of the mermithid nematode Romanomermis culicivorax with the immune system of mosquit... more Interactions of the mermithid nematode Romanomermis culicivorax with the immune system of mosquito larvae were examined by scanning electron microscopy. The host immune system rapidly recognised invading parasites, as granulocytes and discharged granules were observed attached to parasitic nematodes within 5 min. Melanin deposition was infrequently observed. As a counter measure, the parasites secreted and shed an extracellular surface coat which aided immune evasion. During the first 4 days of infection, when parasite growth was limited, the coat served as a disposable, renewable barrier between parasite and host that was intermittently shed to cleanse the nematode of adhering host immune products. In the later infection phase the parasite grew rapidly and was beyond the effect of the depleted host immune response. The broad host range of R. culcivorax within culicines may be partly a function of the nonspecific defence it mounts against the host immune system. In summary, shedding...
Biotechniques, Mar 1, 1991
J Invertebr Pathol, 1980
ABSTRACT
Comparative biochemistry and physiology. B, Comparative biochemistry, Jan 15, 1974
Dihydrofolate reductase, formyl tetrahydrofolate synthetase and methylene tetrahydrofolate dehydr... more Dihydrofolate reductase, formyl tetrahydrofolate synthetase and methylene tetrahydrofolate dehydrogenase were compared in Aphelenchus avenae and Nippostrongylus brasiliensis. 2. Dihydrofolate reductase activity was highest in N. brasiliensis. 3. Methylene THF dehydrogenase activity was similar in both species. 4. Formyl THF synthetase activity was highest in the infective larvae of N. brasiliensis. 5. Formyl THF synthetase was partially purified from A. avenae and N. brasiliensis. 6. The K~ for tetrahydrofolate was lower for formyl THF synthetase from A. avenae but the Km's for ATP and formate were similar for the enzyme in both nematodes.
Hua xi yi ke da xue xue bao = Journal of West China University of Medical Sciences = Huaxi yike daxue xuebao / [bian ji zhe, Hua xi yi ke da xue xue bao bian wei hui], 1992
A new species of Mermithidae was found parasitizing the larvae of Culex tritaeniorhynchus and Cul... more A new species of Mermithidae was found parasitizing the larvae of Culex tritaeniorhynchus and Culex fatigans in Henan, China and then named Romanomermis yunanensis. Thirty-one species of Mosquitoes involving six genera have been tested for susceptibility to R. yunanensis and Culicinae mosquito have consistently been highly susceptible. At a 1:5 ratio of mosquito larvae to nematode juveniles, the parasitisms of Aedes aegypti, Ae. albopictus, Culex fatigans, Culex tritaeniorhynchus, Anopheles sinensts, Psorophora columbiae and Culesta inornata were 98.2%, 98.5%, 98.6%, 97.1%, 0%, 98.8%, and 99.0% respectively. R. yunanensis presented a phenomenon of retarted development in Anopheles maculatus, which remained at the parasitic stage both in the larvae and pupa of An. maculatus. The parasitism of An. dirus was 89.7%, but most (88.8%) parasitizing mermithids underwent melanization and died. The comparative susceptibility of some North American mosquitoes to R. yunanesis and R. culicivorax...
Subcellular fractions of the bird malaria, Plasmodium lophurae , were prepared by differential ce... more Subcellular fractions of the bird malaria, Plasmodium lophurae , were prepared by differential centrifugation. Cytochrome oxidase activity was located in the mitochondrial fraction. A major portion of glutamate dehydrogenase activity was found in the mitochondrial fraction with the remainder in the ribosomal and cytosolic fractions. Malate dehydrogenase and serine hydroxymethyltranaferase activities were located primarily in the cytosolic fraction .
Background. The mermithid nematode Romanomermis iyengari is one of several natural control altern... more Background. The mermithid nematode Romanomermis iyengari is one of several natural control alternatives to synthetic pesticides for mosquito suppression. The commonly used mass rearing procedure of R. iyengari involves the use of coarse sand as a substrate for nematode maturation and oviposition. The coarse sand technique gives excellent nematode productivity in North America. However, under West African climatic conditions, this technique generates relatively lesser amounts of infectious worms. We evaluated coconut coir fibres as a replacement for coarse sand to improve yields in largescale production of R. iyengari in Benin, West Africa. Materials and Methods. Culex quinquefasciatus was the host for the nematodes, and mosquitoes were blood-fed on chickens. Four days after blood feeding, egg rafts were collected and transferred into trays, each containing 2 l of water. The mosquito larvae were fed with fish food. When the mosquito larvae reached the second instar, preparasites (J2) were added (3 J2/larva) to the incubation trays. Eight days after infection, post-parasitic juveniles were separated from the water containing dead mosquito larvae and other debris using sieves and needles; 2 g of them were deposited in containers with coarse sand or coconut coir fibres and water. Three hours later, the water was drained, the jars covered and stored for eight weeks, after which J2 abundance was determined, using a total of 320 containers for each substrate. The abundance of J2 preparasites was also assessed 3-5 months after storage to determine the impact of long-term storage on the J2 yield. Results. After 2 months storage, 2 g of post-parasites (~457 females and 583 males) yielded an average of 559,300±6094 J2 and 155,818±4427 J2 per container for coconut fibres and for coarse sand, respectively. During long-term storage, yields of J2 on coconut fibres substrate slowly decreased from 442,180±9322 J2 (3 months storage) to 163,632±12,416 J2 per container (5 months storage). On coarse sand substrate, the yield was relatively low and decreased from 49,812±1200 J2 at 3 months storage to 3046±229 J2 at 5 months storage. Conclusion. Under West African climatic conditions, coconut coir fibres gave significantly higher preparasitic nematode yields than the coarse sand technique.
Journal of Invertebrate Pathology, Aug 1, 1986
The energy status of Rorncrnorrzrr-/nis c,rt/ic,i,,o,.a.r-parasitized and control CltlcJ.tpipietl... more The energy status of Rorncrnorrzrr-/nis c,rt/ic,i,,o,.a.r-parasitized and control CltlcJ.tpipietls larvae was studied in vivo with jlP nuclear magnetic resonance (NMR) at 4-6°C. Peak assignments were made for inorganic phosphorus, phosphoarginine. AMP, ADP. and ATP. The mean ATPiADP ratios were 4.45 for control and 4.02 and 2.94 for parasitized mosquito larvae with I .3 and 2.3 parasites per host, respectively. The ATPiADP ratios for control mosquito larvae reared with a pH of 7 and 4.5 were not significantly different. R. ctrlici\wtrx parasitism had no significant effect on the ATP level in whole mosquito larvae. The mean ATP concentrations were 9.86 and I I .64 nmolimg dry weight mosquito for control and parasitized larvae. respectively. R. c~rrlici~wrcrx postparasites t IO days post-infection) were shown to have a very weak 31P NMR signal and it was concluded that the parasites contribute little to the NMR spectra of infected mosquito larvae. Enzymatic analysis of perchloric acid-extracted control mosquito larvae yielded 9.3 nmol ATPimg dry wt and 2.6 nmol ATPimg dry weight for R. ctrlicirwux postparasites at IO days post-infection. I 19x6 Academ>c PX\\. Inc.
Magnetic Resonance in Medicine, Nov 1, 1990
3'P NMR spectroscopy of a parasitic nematode, Sfeinernema caryocaysue, is described.
Comparative Biochemistry and Physiology a Comparative Physiology, Feb 1, 1984
l.
Proceedings of the National Academy of Sciences of the United States of America, Mar 4, 2003
Bacillus thuringiensis (Bt) crystal proteins are pore-forming toxins used as insecticides around ... more Bacillus thuringiensis (Bt) crystal proteins are pore-forming toxins used as insecticides around the world. Previously, the extent to which these proteins might also target the invertebrate phylum Nematoda has been mostly ignored. We have expressed seven different crystal toxin proteins from two largely unstudied Bt crystal protein subfamilies. By assaying their toxicity on diverse free-living nematode species, we demonstrate that four of these crystal proteins are active against multiple nematode species and that each nematode species tested is susceptible to at least one toxin. We also demonstrate that a rat intestinal nematode is susceptible to some of the nematicidal crystal proteins, indicating these may hold promise in controlling vertebrate-parasitic nematodes. Toxicity in nematodes correlates with damage to the intestine, consistent with the mechanism of crystal toxin action in insects. Structure-function analyses indicate that one novel nematicidal crystal protein can be engineered to a small 43-kDa active core. These data demonstrate that at least two Bt crystal protein subfamilies contain nematicidal toxins.
Cellular Immunology, Mar 31, 1989
To investigate whether the formation of IgE is linked in vivo to an IgG subclass, mice were infec... more To investigate whether the formation of IgE is linked in vivo to an IgG subclass, mice were infected with four helminth parasites, Nippostrongylus brasiliensis (Nbr), Mesocestoides corti, Taenia crassiceps and Trichinella spiralis, and the changes in the serum levels of the different Ig isotypes as well as the antibody response to M. corti and T. crassiceps antigen extracts were determined by radioimmunoassays. All four parasites induced a concomitant increase of the IgE and IgGl serum levels and usually a decrease of the IgG2a level. They also induced an increase of the IgM level but had little effect on the IgGZb, IgG3, and IgA serum levels. The specific antibodies to an M. corti antigen extract were mainly of the IgGl subclass, whereas it was of both IgGl and IgG2a subclasses to T. crassiceps. Injections of dead M. corti induced an increase of all IgG subclasses and similar levels of IgGl and IgG2a anti-parasite antibodies. Subcutaneous instead of intraperitoneal infection with T. crassiceps induced higher IgG2a than IgGl levels and lo-fold lower IgE levels than the natural ip infection; however, despite the greater IgG2a polyclonal response, anti-parasite antibodies were predominantly of the IgGl subclass. The data demonstrate that natural infection with four different helminth parasites induces a concomitant polyclonal IgGl and IgE response. These in vivo observations corroborate the recent in vitro findings demonstrating that interleukin-4 induces lipopolysaccharideactivated murine B cells to secrete both IgGl and IgB, suggesting that the regulation of these two isotypes is linked.
Journal of Nematology, Aug 1, 1985
Uhrastructural study of the body wall of preparasitic, parasitic, and postparasitic stages of Rom... more Uhrastructural study of the body wall of preparasitic, parasitic, and postparasitic stages of Romanomermis culicivorax showed that the cuticle of all three stages was permeable to lanthanum.
Comparative Biochemistry and Physiology, 1970
ABSTRACT
Insect Biochemistry, 1984
Tricarboxylic acid cycle intermediates in the haemolymph of healthy and infected larvae of Culex ... more Tricarboxylic acid cycle intermediates in the haemolymph of healthy and infected larvae of Culex pipiens, Aedes taeniorhynchus and Anopheles quadrimaculatus were determined by enzymatic analyses and gas-chromatographic procedures. Pyruvate increased by over 100~o in C. pipiens late fourth stage healthy larvae compared with early fourth stage larvae and a-ketoglutarate contents were reduced in the late fourth stage larvae of all three species. Malate was the predominant haemolymph acid with appreciable amounts of citrate and lactate. Haemolymph from larvae infected with Romanomermis culicivorax, compared with that from healthy larvae of C. pipiens and A. taeniorhynchus showed no change in succinate, but fumarate, malate and citrate concentrations were higher. Lactate and ~-ketoglutarate concentrations were elevated in A. taeniorhynchus but remained unchanged in the other two species. Oxaloacetate was reduced to undetectable levels in C. pipiens and A. taeniorhynchus infected larvae. Lactate, succinate, malate, oxaloacetate and fumarate remained unchanged between healthy and infected A. quadrimaculatus larvae, but citrate and pyruvate were reduced. Pyruvate concentration was also reduced in C. pipiens infected larvae, but remained constant in A. taeniorhynchus.
Insect Biochemistry, 1984
A method is described for the quantitative analysis of some components of the tricarboxylic acid ... more A method is described for the quantitative analysis of some components of the tricarboxylic acid cycle in microsamples (25/~1) of insect haemolymph. The method involves purification using ion-exchange chromatography, followed by gas chromatography of the acids as their trimethylsilyl derivatives. Particular attention has been paid to the treatment of ion-exchange resin before addition of sample and to methods of drying prior to derivatization to minimize losses. The effects of deproteinization on haemolymph acid content were studied using [~4C]citric acid and oleic acid. Results are presented for studies completed on the haemolymph of the fourth stage larvae of the mosquito Culex pipiens. Malic acid constituted the major component of the TCA cycle acid metabolites, with appreciable quantities of lactic and citric acids. Succinic and fumaric acids were also present.
International Journal For Parasitology, Sep 30, 1988
A method for surface sterilization of large numbers (> 5 000) of preparasites of Romanomermis cul... more A method for surface sterilization of large numbers (> 5 000) of preparasites of Romanomermis culicivorax is presented. Grace's insect tissue culture medium (GITC) was supplemented with fetal bovine serum and bovine albumin and used as a basal test medium (BB) for in vitro culture attempts with R. culicivorax preparasites. Experiments were run in 1 ml of test media in sealed glass tubes for 21 days at 27 f 1' at densities of about 146 parasitesltube. Various modifications of the test medium were evaluated. The mean growth of R. culicivorax was measured with the Bradford protein assay and compared to a growth equation attained in vivo. One of the best media rested was GITC medium with the Salt concentrations altered to that reported for the hemolymph of fourth instars of Culex pipiens, the amino acid concentrations based on hydrolyzed female R. culcivorax postparasites, and reduced glutathione (200 mg/l) was added (RCg). Average growth in this medium was 944.4 ng proteinlparasite which was equivalent to 4.2 days growth in vivo. A significant decrease in growth (P < 0.05) was noted when parasite densities per tube were