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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Certain tasks in the studies of Mermithoidea for biological control of moths].

The method of "flooding" with mermitids, which was successfully used against mosquitoes, is unreal for biological control of black flies because of difficulties and unprofitableness of their laboratory maintenance and reproduction. A more probable way of solving the problem is the untroduction of effective forms of parasites. In perspective the cultivation of the adipose tissue of the host and biochemical overcoming of its protective reactions are necessary.

Animals↗
PubMedDate not supplied

[A new family of Nematodes, parasites of marine invertebrates, the Benthiumermithidae (author's transl)].

Nematodes of a group related to the Mermithoidea and known only from a preliminary note by Hope (1977) have been found either as parasites of invertebrates (only female juveniles) or free-living (mature and juvenile females) in benthic sediments of the Atlantic Ocean, the Norway Sea, and the Indian Ocean. The characters in common in the group are given. Benthimermis hopei, n. g., n. sp., known from one mature and one juvenile females found free in benthic sediments of the Atlantic Ocean is described, as well as 8 juvenile females found free in benthic sediments of the Atlantic Ocean is described, as well as 8 juvenile females (Benthimermis sp., nos 1-8), of which 7 are parasites of invertebrates and one was found free in sediments. A new family is proposed for the group, the Benthimermithidae, characterized by a vestigial oesophagus, reduced to a strand containing granular material, an intestine modified into a trophosome, and a vestigial rectum and anus.

Animals↗
PubMed1978

[Parasitic influences on undifferentiated tissue (author's transl)].

The imaginal discs of chironomid larvae infected with mermithid nematodes provided a useful model for the study of parasitic effects upon undifferentiated tissue. Specific aberrations concerning mitotic rate, cell death, organogenesis, cell pattern differentiation and cell differentiation are described and discussed.

Animals↗
PubMed1994

Distribution of catecholamine(s) in the nervous system of a mermithid nematode, Romanomermis culicivorax.

The nervous system of the mermithid nematode Romanomermis culicivorax was investigated at different developmental stages for the distribution of catecholamine(s). The catecholaminergic nervous system increased in complexity during development. In the adult nematode, catecholamine(s) occurred in the nerve ring and associated ganglia, cephalic nerves, ventral and dorsal nerve cords and mid-body region ganglia. The distribution of catecholaminergic ganglia in the tail region was different for each sex. The tail region of males contained 16-20 catecholaminergic ganglia, whereas the tail of females contained only 2 ganglia. The catecholamine widely distributed throughout the nervous system of R. culicivorax is not dopamine, since immunoreactivity to dopamine was observed only in the amphids. The results suggest that the catecholamine(s) is widely distributed within the nervous system of R. culicivorax and might function as a neurohormone or neurotransmitter in controlling physiological and developmental processes.

Aedes↗
PubMed1994

Distribution of FMRF-amide-like peptide in the nervous system of a mermithid nematode, Romanomermis culicivorax.

The nervous system of the mermithid nematode Romanomermis culicivorax was investigated at different developmental stages for the distribution of the neuropeptide FMRF-amide. An FMRF-amide-like peptide was detected by an indirect immunofluorescence technique. The peptidergic nervous system increased in complexity during development. In adults, FMRF-amide-like peptide was present in the nerve ring, cephalic papillary ganglia, cephalic nerves, amphids, ganglia posterior to the nerve ring, longitudinal nerve cords and several mid-body region ganglia. The distribution of peptidergic ganglia in the tail region was different for each sex. Four clusters of ganglia were present in the tail of females, whereas such ganglia were absent in the tail of males. The results suggest that FMRF-amide-like peptide is widely distributed within the nervous system of R. culicivorax and might function as a neurohormone or neurotransmitter in controlling physiological and developmental processes.

Aedes↗
PubMed2001

Chromosomal polymorphism is associated with nematode parasitism in a natural population of a tropical midge.

A natural population of a tropical midge, Chironomus ramosus (Diptera: Chironomidae), was found to be polymorphic for a paracentric inversion (IV: 18C-19D). Based on the characteristic banding pattern of the fourth chromosome in the larval salivary gland polytene nuclei, individuals were classified as either structural homozygotes or heterozygotes. Isofemale lines were obtained and subsequently standard (S/S) and inversion (I/I) homozygotes were characterised by careful progeny testing in the laboratory. While exploring various biotic and abiotic factors that might be responsible for the maintenance of inversion polymorphism, we detected nematode (Family: Mermithidae) infections among the larval population. A detailed study indicated that the inversion polymorphism in the natural population of C. ramosus was apparently being maintained as a result of the selective pressure exerted by the nematode parasite. The corresponding pattern of increase and decrease in genotype frequencies and the relative fitness values indicated a selective advantage of inversion heterozygotes (S/I) over both homozygous types (S/S and I/I). Both empirical and experimental data suggest the strong heterotic nature of adaptation in this C. ramosus population towards nematode infection. This is the first report of its kind where inversion polymorphism has been shown to be associated with nematode parasitism.

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