[In vitro observation of the action of isolates of the fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on the eggs of Ascaris lumbricoides (Linnaeus, 1758)]. / Observação in vitro da ação dos isolados fúngicos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides (Lineu, 1758).

The in vitro action of the nematophagous fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on eggs of Ascaris lumbricoides was observed. After 7, 10 and 14 days of interaction, the fungus showing most promise for use in biologically control over Ascaris lumbricoides was Verticillium chlamydosporium (26-30%). The other fungi did not present satisfactory results.

Observação in vitro da ação dos isolados fúngicos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides (Lineu, 1758) / In vitro observation of the action of isolates of the fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on the eggs of Ascaris lumbricoides (Linnaeus, 1758)

Observou-se a ação in vitro dos fungos nematófagos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides. Após sete, dez e quatorze dias de interação, o fungo promissor a ser utilizado no controle biológico de Asaris lumbricoides foi o Verticillium chlamydosporium (26-30 por cento). Os outros fungos não foram satisfatórios.

The in vitro action of the nematophagous fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on eggs of Ascaris lumbricoides was observed. After 7, 10 and 14 days of interaction, the fungus showing most promise for use in biologically control over Ascaris lumbricoides was Verticillium chlamydosporium (26-30 percent). The other fungi did not present satisfactory results.

[The effect of biotic factors on the eggs of Ascaris spp]. / Wplyw czynników biotycznych na jaja Ascaris spp.

There are many organisms that influence development and survival of eggs of Ascaris sp. Fungi, Acari, Collembola and bacteria are the most important among them. They participate mainly in auto-dehelminthisation processes of environment.

Colonization of Ascaris lumbricoides eggs by the fungus Verticillium chlamydosporium Goddard.

The process of colonization of Ascaris lumbricoides eggs by the fungus Verticillium chlamydosporium was studied by scanning electron microscopy. The preparations were made by fractionation of egg suspension exposed to the fungus for four days and frozen in liquid nitrogen according to Sterba and Milácek (1986). Ovicidal fungus forms an abundant ramifying mycelial network in the area between the eggs. However, egg-shells are penetrated only by some hyphae without any penetration organs produced (simple hyphal penetration). In a liquid medium, after penetration, hyphae inside the eggs rapidly grow among inner structures of egg-shells and on the surface of developing larvae. In the next phase, hyphae colonize the developing larva. The eggs attacked by this fungus remain morphologically unchanged for a long time except the sites of penetration. Verticillium chlamydosporium is a fungus with unique ovicidal properties. It colonizes the eggs of Ascaris lumbricoides at all stages of embryo development and also attacks larvae inside the eggs.

Penetration of ovicidal fungus Verticillium chlamydosporium through the Ascaris lumbricoides egg-shells.

The course of penetration of the ovicidal fungus Verticillium chlamydosporium Goddard through the Ascaris lumbricoides egg-shells was studied in electron miorographs. The contact area between the egg and the fungus is smooth at the stage of the contact of the ovicidal fungus with the egg surface, as well as at the stage of adhesion. No special attaching organs are formed which indicates that no mechanical penetration of the fungal hypha through the egg-shells is involved. Traces of enzymatical activity of the fungus penetrating upright through the egg-shells can be observed during the penetration stage proper. At the consumption stage, the branching of the ovicidal fungus becomes more dense and some hyphae grow through the egg envelopes parallelly under the egg surface. The fungus grows through all parts of the infected egg, even through its contents.

Structure and genomic organization of proretrovirus-like elements partially eliminated from the somatic genome of Ascaris lumbricoides.

A clone containing a middle repetitive element next to satellite DNA has been isolated from a germ line genomic library of the chromatin eliminating nematode Ascaris lumbricoides var. suum. The structure of this element has been elucidated by comparison of several clones containing the element in different environments. It is flanked by 256-bp-long terminal repeats (LTRs) and has an internal region of approximately 7 kb. The nucleotide sequences of both the 5' and the 3' LTRs have been determined. The element has a strong structural similarity with retroviral proviruses and related mobile elements. It was therefore named 'Tas', for transposon-like element of Ascaris. Approximately 50 Tas copies are dispersed over approximately 20 different chromosomal sites. Their genomic distribution varies between individuals, indicating that Tas elements are mobile in the Ascaris genome. Two variant forms, Tas-1 and Tas-2, present in a ratio of approximately 2 to 1 in the germ line genome, have been characterized. They differ not only in their restriction pattern, but also in their elimination behaviour. While only about one-fourth of the Tas-1 elements are expelled from the somatic cell lineage, all Tas-2 copies are specifically eliminated and are thus confined to the germ line cells. We have demonstrated that a cloned representative of Tas-1 elements is expelled concomitantly with its flanking DNA sequences during the chromatin elimination process.

Ascaris lumbricoides as a vehicle of bacterial infections.

Investigations were conducted on microflora on the body surface and internal organs of adult Ascaris lumbricoides. The investigations involved examination of wet faecal preparations of over 100 pupils using light microscope. The body surface of the adult Ascaris worms was cultured on selective media. Adult worms were dissected and different parts of the worms' gut were cultured for isolation of micro-organisms. The results of the bacteriological examination of the body surface of A. lumbricoides yielded many genera of bacterial organisms. The results from internal organs of dissected adult Ascaris worm yielded varying percentages of organisms similar to those found on the surface of the worm. The possibility of linking Ascaris infection with this aetiology of pyrexia of unknown origins as commonly seen in tropical regions was discussed.

The bacterial flora of the intestine of Ascaris suum and 5-hydroxytryptamine production.

Representative facultative anaerobes of the bacterial flora from the intestine of female Ascaris suum were isolated and identified. The number of bacteria in the intestine was approximately 4 X 10(9) per g wet weight of intestine. Seventeen of 19 of the isolated colonies were found to secrete 5-hydroxytryptamine in culture. Holding A. suum in an antibiotic-containing medium did not affect the levels of 5-hydroxytryptamine in the worm, which were 231 +/- 14 ng/g in antibiotic-media as compared to 250 +/- 16 ng/g in control media. This implied that the bacteria may not be contributing to the level of 5-hydroxytryptamine in the tissues of A. suum.

Penetration of ovicidal fungi through altered egg-shells of Ascaris suum.

Ovicidal activity was studied in microscopic fungi penetrating into and destroying eggs of geohelminths surviving in the soil. The character of penetration was compared in eggs obtained mechanically with those obtained by means of a chemical process. A total of 13 strains of ovicidal fungi of 4 species were studied. The shells of eggs obtained by the chemical process were so altered that under the same conditions they were attacked and penetrated by the fungi much more than the eggs obtained by a mechanical way. The advantages and disadvantages of these two methods of eggs isolation are discussed.