Parasitic Juveniles Research Articles

Sphaerularia vespae sp. nov. (Nematoda, Tylenchomorpha, Sphaerularioidea), an Endoparasite of a Common Japanese Hornet, Vespa simillima Smith (Insecta, Hymenoptera, Vespidae)

Sphaerularia vespae sp. nov., an endoparasite of a common Japanese hornet, Vespa simillima is described from Hokkaido, Japan, and its molecular sequence profiles are given. This newly discovered nematode appears to belong to the genus Sphaerularia, judging from its characteristic parasitic form, the uterium, which looks like a sausage with many verrucae on its surface. Sphaerularia vespae sp. nov. is distinguished from S. bombi, the only other nominal species of the genus, by the morphology of the male bursa, female tail, and anterior end of parasitic juveniles. SSU, ITS, and D2D3 (LSU) DNA sequences were determined for S. vespae sp. nov. and compared with those from related nematodes obtained from the GenBank database. The sequences from S. vespae sp. nov. were close to those of S. bombi and several another tylenchid entomoparasitic nematodes. Sphaerularia vespae sp. nov. parasitizes overwintering gynes of the hornet and practically sterilizes them, as S. bombi does for bumblebee gynes.

A new class of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in plant parasitic cyst nematodes.

By performing cDNA AFLP on pre- and early parasitic juveniles, we identified genes encoding a novel type of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in the cyst nematode Heterodera schachtii. The proteins consist of three domains, a signal peptide for secretion, a mono-ubiquitin domain, and a short C-terminal positively charged domain. A gfp-fusion of this protein is targeted to the nucleolus in tobacco BY-2 cells. We hypothesize that the C-terminal peptide might have a regulatory function during syncytium formation in plant roots.

Development and application of an ELISA for a sex pheromone released by the male sea lamprey ( Petromyzon marinus L.)

An enzyme-linked immunosorbent assay (ELISA) has been developed for a conjugated bile acid, 7α,12α,24-trihydroxy-5α-cholan-3-one 24-sulfate (commonly referred to as 3-keto petromyzonol sulfate [3kPZS]), a pheromone released by reproductively mature male sea lampreys to attract sexually mature females. A polyclonal antiserum against the pheromone was raised by injecting 3-keto petromyzonol 24-hemisuccinate (3kPZ-HS) conjugated to bovine serum albumin into rabbits. The enzyme label was prepared by conjugating 3kPZ-HS to acetylcholinesterase. The standard curve had a working range of 20 pg–10 ng/well. Intra- and inter-assay variations were less than 5 and 12%, respectively. The antiserum had 100% cross-reaction with 3-keto petromyzonol and 3-keto allocholic acid but less than 0.2% cross-reaction with petromyzonol, allocholic acid, cholic acid, and taurolithocholic acid sulfate. The assay was applied to water which had been conditioned for 4 h by either larvae, parasitic juveniles, ovulating females, pre-spermiating males, or spermiating males. Immunoactive material (average 200 ng/ml, which is equivalent to 500 μg animal/h) was only found in water from the reproductively mature males and diluted parallel with the standard curve. Assay of water samples collected from male lampreys in bisected aquaria also established that 99.6% of the immunoactive material emanated from the front end of the fish. This assay has applications in both physiological and ecological aspects of sea lamprey reproduction.

Differences in the fatty acid composition of larvae and metamorphosing sea lampreys, Petromyzon marinus

This study was designed to evaluate biochemical changes in the fatty acid (FA) compositions of selected lipid depot (kidney and liver) and absorption (intestine) organs in larvae and metamorphosing sea lamprey, Petromyzon marinus. Palmitic or stearic acids were generally the predominant saturated fatty acids (SFA) before and during metamorphosis, but the greatest proportion of myristic acid occurred in renal triacylglycerol (TG). Monoenes, dienes, and polyenes consist mainly of 16:1, 18:1, and 20:1, 18:2 and 20:2ω6, and 18:4ω3, respectively. Alterations in these predominant fatty acids occurred during lamprey metamorphosis, but depended on tissue, lipid class, and developmental status. During metamorphosis, kidney TG and phospholipid (PL) classes tended to mobilize SFA and enhance the fatty acid unsaturation, as indicated by increased unsaturated/saturated ratio, unsaturation index (USI), and total mean chain length (MCL). There was a tendency to increase saturation in the fatty acids of liver TG and PL classes and intestine TG, FA and monoacylglycerol (MG) classes, but to increase unsaturation in the fatty acids of liver cholesteryl ester (CE), FA and MG classes and intestine PL and CE classes from larva or stage 3 to stage 7. Increased polyunsaturated fatty acids in kidney TG and PL from larvae to stage 5 transformers and intestine PL and CE from stage 3 to stage 7 transformers may reflect an osmoregulatory pre-adaptation. The presence of branched-chain SFA (BCSFA) and the odd number of fatty acids (ONFA) indicated a significant role of detritivores in the benthic larvae. Decreased abundance of BCSFA, ONFA, and 18:2 dienes occurred in the transformed intestine TG as non-trophic metamorphosis proceeded. These data suggest that sea lamprey metamorphosis may proceed in a habitat, dietary, osmoregulatory, energetic, and developmental pre-adaptation of fatty acid composition from benthic filter-feeding larvae to pelagic parasitic juveniles.

Emergence rates from the benthos of the parasitic juveniles of gnathiid isopods

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 207:123-127 (2000) - doi:10.3354/meps207123 Emergence rates from the benthos of the parasitic juveniles of gnathiid isopods Alexandra S. Grutter1,*, Robert J. G. Lester1, Jack Greenwood2 1Department of Microbiology and Parasitology and 2Department of Zoology and Entomology, The University of Queensland, Brisbane, Queensland 4072, Australia *E-mail: a.grutter@mailbox.uq.edu.au ABSTRACT: Variation in the rate at which parasitic gnathiid isopod juveniles emerged from the benthos at Lizard Island, Great Barrier Reef, Australia, was examined (1) every 4 or 8 h throughout the day and night over a 24 h period, (2) over a 12 h period during the day or night, and (3) during different lunar phases (weeks). The number of gnathiids sampled per 4 or 8 h was low, with only 30% of the traps containing gnathiids and the abundance ranging from 0 to 3 gnathiids m-2. The number of gnathiids that emerged over 12 h, in contrast, ranged from 0 to 36 m-2. During the third and fifth weeks sampled, more gnathiids emerged during the day than at night. This coincided with the full moon and new moon. Most gnathiids that emerged from the reef during the day (98%) had not fed, in contrast to those sampled at night (71%). Of the gnathiids with no engorged gut, most (97%) of those collected during the day were small (≤1 mm) compared to those collected at night (19%), the latter being mostly >1 mm. Of the gnathiids with an engorged gut, most were sampled at night (83%) and 97% were >1 mm in size. These percentages suggest differences in the emergence behaviour among life stages or species of gnathiids. This study, which shows that gnathiids do emerge during the day and supports other studies showing that gnathiids also attack fishes during the day, has important implications for understanding the role of cleaner fish and their main food source, gnathiids, as it shows there is a constant source of gnathiids emerging from the reef during the day and night in search of hosts. KEY WORDS: Crustacea · Gnathiidae · Isopoda · Ectoparasites · Great Barrier Reef · Demersal zooplankton · Emergence behaviour · Emergence traps · Lunar periodicity Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 207. Online publication date: November 22, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.

Infestation dynamics of gnathiid isopod juveniles parasitic on the coral-reef fish Hemigymnus melapterus (Labridae)

The dynamics of infestation by parasitic juveniles of gnathiid isopods were investigated at Lizard Island in the summer of 1997/1998 to determine when, and at what rate, they infest fishes. Variation in gnathiid abundance on wild-caught fish (Hemigymnus melapterus) between dawn and sunset was examined, and unparasitized H. melapterus in cages were exposed to gnathiids in the field for 4 h (8 h for fish sampled at 06:00 h) at five different times of the day and night (10:00, 14:00, 18:00, 22:00, 06:00 hrs) on three reefs. To control for any potential effect of the cleaner-fish Labroides dimidiatus, which consumes large numbers of gnathiids each day, sampling was carried out on reefs from which all cleaner-fish had been removed. Gnathiid abundance decreased during the day. Standardized abundance per wild-caught fish was 1.9 times higher at dawn than at sunset. Gnathiids successfully infested fish in cages. Sixty-one percent of the fish in cages were infested with greater than or equal to 1 gnathiids, with 51% of the fish having between 1 and 4 gnathiids after 4 h exposure. Gnathiids infested fish both day and night. The log(10) (abundance +1) of gnathiids per caged fish varied significantly between time periods, with higher gnathiid numbers on fish sampled at 18:00, 22:00, and 06:00 hrs than on fish sampled at 10:00 and 14:00 hrs. In contrast to gnathiid abundance on wild-caught fish, the number of gnathiids on caged fish sampled at sunset was as high as that at dawn. The estimated mean (SE) cumulative number of gnathiids per caged fish [mean size = 13.7 cm (+/-0.25)] per day was 7.8 (1.1); this is similar to the estimated mean number of 7.3 gnathiids on similar-sized wild-caught fish at 6:00 hrs. The high infestation rate of gnathiids on caged fish in the late afternoon contrasted with the low numbers on wild-caught fish at this time, suggesting that factors other than infestation behaviour may be responsible for the low numbers of gnathiids on wild-caught fish in the afternoon.

In plantamonitoring of the activity of two constitutive promoters, CaMV 35S and TR2′, in developing feeding cells induced byGlobodera rostochiensisusing green fluorescent protein in combination with confocal laser scanning microscopy

Under the control of either the constitutive CaMV 35S or the mannopine synthase TR2′ promoter, the green fluorescent protein (GFP) from the jellyfishAequorea victoriawas expressed in transgenic potato (Solanum tuberosum) plants. Confocal laser scanning microscopy (CLSM) was applied to observe GFPin plantaand, subsequently, to investigate promoter activity in developing feeding cells developed during potato cyst nematode (Globodera rostochiensis) infection. Both the CaMV 35S and the TR2′ promoter were strongly upregulated in young feeding cells in less than 4 days upon infection byG. rostochiensis,whereas the GFP level in the surrounding tissues remained low. Optical sectioning revealed intense green fluorescence in the dense cytoplasm of the entire syncytial cell, including the most distal cell. Furthermore, GFP was observed within the digestive system of the feeding nematode, showing that proteins with an apparent molecular weight of 32 kDa can be taken up by parasitic juveniles ofG. rostochiensis. Provided CLSM is used, GFP was shown to be a powerful tool that allowsin vivomonitoring of gene expression inside young developing feeding cells. Finally, the transcriptional regulation of the CaMV 35S and TR2′ promoter in plant–nematode interactions is discussed.

Parasitism of overwintering grasshoppers by mermithid nematodes

Advanced parasitic juveniles of the nematode Amphimermis acridiorum were recorded in mid‐spring in grasshopper species which overwintered in the southern tablelands of New South Wales. Hosts included adult Perala viridis and nymphal Urnisa sp. The observation confirms that parasitism by mermithid nematodes may occur prior to the hatching of summer grasshopper hosts. The implications for parasitism of summer hosts such as Phaulacridium vittatum are discussed.

Gastromermis cordobensis n. sp. (Nematoda: Mermithidae) parasitizing Simulium lahillei Patterson & Shannon (Diptera: Simuliidae) in Argentina

Gastromermis cordobensis n. sp (Nematoda: Mermithidae) a parasite of larvae of the blackfly Simulium lahillei Paterson & Shannon (Diptera: Simuliidae) in Argentina, is described. Diagnostic characters of this species include a mouth ventrlly shifted; six cephalic papillae; eigh hypodermal chords; small and pear shaped amphids; a long and S-shaped vagina; a singl spicule, which is long, has non-uniform walls, and a tip with sculpture; three rows of genital papillae, the middle one with 18 pre-anal and 10 post-anal papillae, the lateral rows have 36 papillae each; oval eggs; and post-parasitic juveniles with long thin tails. Pre-parasitic and parasitic juveniles are included in the description.

The Effect of Host Stage and Temperature On the Development of Hexamermis Sp. (Nematoda: Mermithidae) in the Australian Plague Locust Chor Toicetes Terminifera (Walker) (Orthoptera: Acrididae)

Female Chortoicetes terminifera were infected in the laboratory by a mermithid nematode, Hex- amermis sp., to determine the effect of host stage and temperature on development of the parasite. The rate of infection achieved in the laboratory was higher in instars one and two than in instars three, four, five and the adult. This was attributed to differences in the rate of phagocytosis of parasitic juveniles between these host stages. The duration of parasite development was independent of host stage with the mean duration for all host stages being 24.2 d at 25°C. There was a negative relationship between the duration of parasite development and temperature. The mean duration in third instar hosts was 54 d at 20°C, 23.4 d at 25°C, 16.2 d at 30°C and 14.5 d at 35°C. The mean body length of nematodes on emergence from the host was positively related with host stage. The body length of nematodes on emergence from the host was independent of temperature.

Ultrastructure of esophageal glands and their secretory granules in the root-knot nematodeMeloidogyne incognita

The dorsal and subventral esophageal glands and their secretory granules in the root-knot nematodeMeloidogyne incognita changed during parasitism of plants. The subventral esophageal glands shrank and the dorsal gland enlarged with the onset of parasitism. While secretory granules formed by both types of glands were spherical, membrane-bound, and Golgi derived, the granules differed in morphology and size between the two types of glands. Subventral gland extensions in preparasitic second-stage juveniles were packed with secretory granules which varied in diameter from 700–1,100 nm and had a finely granular matrix. Within the matrix of each subventral gland granule was an electron-transparent core that contained minute spherical vesicles. The size and position of the core varied within different granules. Few granules were present in the dorsal gland extension in preparasitic juveniles. The matrix of dorsal gland secretory granules formed during parasitism was homogeneous and more electron-dense than the matrix of subventral gland granules. Subventral gland secretory granules of parasitic juveniles and adult females appeared degenerate.

Brugia pahangi: Development in Aedes aegypti reared axenically on a defined synthetic diet

Adult Aedes aegypti axenically reared on a chemically defined dietary medium had low infectivity to Brugia pahangi, and harbored few third-stage parasitic juveniles. Some of these parasites appeared not to have completed the second molt at the end of 10 days of incubation. Mortality was high in mosquitoes from axenic larval rearings, especially during filarial infection. It appeared probable that adverse effects on the worm resulted from suboptimal host nutrition. Thus, manipulations of the chemically defined dietary medium used to rear A. aegypti may be used to study the influence of specific nutrients on filarial development.

Body wall of juvenile and adult Gastromermis boophthorae (Nematoda: Mermithidae): Ultrastructure and nutritional role

During the life cycle of the mermithid nematode Gastromermis boophthorae the main components of the body wall, namely the cuticle, hypodermis and somatic musculature, undergo radical changes in structure and relative proportions. In the non-feeding, free-living stages the cuticle is a well-defined, multilayered structure which lies upon a generally thin hypodermis; the somatic musculature has the extensive and highly organised appearance typical of motile nematodes. In parasitic juveniles the body wall has a completely different structure which is adapted for the suggested purpose of nutrient uptake from the host insect's haemocoelomic fluid; the cuticle is characteristically thin and rather diffuse, the underlying hypodermis becomes very extensive and metabolically active, and there is a corresponding reduction in the proportion of somatic musculature. The sub-cuticular surface of the enlarged hypodermis has a microvillous configuration and has associated alkaline phosphatase activity.

NEW RECORDS OF HEXAMERMIS (NEMATODA: MERMITHIDAE) PARASITIZING THREE SPECIES OF SLATEROCORIS (HEMIPTERA: MIRIDAE)

The parasitic juveniles of mermithid nematodes attack a variety of hosts from 15 insect orders (Welch 1963, 1965). Little is known of the extent to which they are parasites of Miridae. Menzel (1922) and Cobb et al. (1927) recorded parasitism of the bug Helopeltis theivora Waterh. by Mermis sp. and by Agamermis paradecauta Steiner, respectively. A related mirid, H. antonii Sign., was reported parasitized by Mermis sp. (Menzel 1922), and by A. paradecauta and Hexamermis microamphidis Steiner (Steiner 1925). Recently King (1969) found that the mirids Sahlbergella singularis (Hagl.) and Distantiella theobroma (Dist.) were hosts of the genus Mermis Dujardin.

New Species of Gastromermis, Isomermis, and Mesomermis (Nematoda: Mermithidae) from Black Fly Larvae1

Caistromermis viridis and Isomermis wisconsinensis are described from larvae of Simulium vittatum Zett. in Wisconsin, and Mesomermis flumenalis from larvae of Simutlium vennstum Say in Ontario. No species of Gastromermis or Isomermis have previously been known from North America. The free-living and parasitic juveniles of all three species, as well as the adults, are described and illustrated.