Studies on parasitic castration: Occurrence of a gametogenesis-inhibiting factor in extract of Zoogonus lasius (Trematoda)

Pearson, E. J.; Cheng, Thomas C.

doi:10.1016/0022-2011(85)90064-3

Cited by 24 publications

(11 citation statements)

References 13 publications

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“…This is in contrast to the report of Junnikkala [19] a certain critical stage. Pearson and Cheng [20] suggested that some component of extracts from the parasite Zoogonus lasius acts as a chemical inhibitory factor in the case of certain Ilyanassa obsoleta spermatogonia in G1 phase and that molecule(s) of parasite origin may cause the lysis of immature and mature gametes, inhibit division and differentiation of immature gametes, and antagonize neurosecretions essential for gamete formation and development.…”

Section: Discussionmentioning

confidence: 99%

Reduction of testis growth of pseudaletia separata larvae after parasitization by cotesia kariyai

Tanaka

Tagashira

Sakurai

1994

Arch Insect Biochem Physiol

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The braconid endoparasitoid, Cotesia j=Apante/es) kariyai physiologically influences its host, Pseudaletia separata, through three factors: polydnavirus, venom, and teratocytes. Inhibiting testis development of the host seems to be one factor that is important for successful development of the parasitoid. CkPV (polydnavirus of Cotesia kariyai) plus venom depressed testis development. Testes from unparasitized day 0 last instar transplanted into isolated abdomens increased in volume after stimulation with 20-hydroxyecdysone (20HE). However, day 0 testis preincubated with CkPV plus venom for 6 h and then transplanted into an isolated abdomen did not respond to 20HE. Southern blot analysis indicated CkPV-DNA hybridized to testes-DNA from parasitized hosts, suggesting the possibility that CkPV is involved in suppression of testes growth. Binding assays using PNA indicated a 2-fold increase in ecdysteroid receptor binding activity during the late stage of parasitism. The increase in receptor activity might be related to the maintenance of a low ecdysteroid titer in parasitized hosts due to a feedback response. 0 1994 Wiley-Liss, Inc. Key words: braconid parasitoid, polydnavirus, venom, ecdysone receptor INTRODUCTIONEndoparasitoids often affect the physiological condition and behavior of their hosts [l]. Parasitism of Pseudaletia sepavata (Walker) by Cotesia (=Apanteles) kariyai (Watanabe) caused several physiological alterations, including inhibition of host pupation [2,31, changes in fat body metabolism [41, and disruption of the immune system [5,6]. Host behavior is also changed during parasitism.

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Section: Discussionmentioning

confidence: 99%

Reduction of testis growth of pseudaletia separata larvae after parasitization by cotesia kariyai

Tanaka

Tagashira

Sakurai

1994

Arch Insect Biochem Physiol

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“…In addition, various studies have found alterations in organs, morphology and physiology of the intermediate host, caused by the presence of trematode larvae in its digestive gland and ovotestis, and as a result its reproductive pattern was also affected 2,5,7,16 . Various phenomena are frequently observed, from a reduction in fecundity to partial or total suppression of the production of gametes, known as parasitic castration.…”

Section: Introductionmentioning

confidence: 99%

The effects of the experimental infection from a focus of transmission of Schistosoma mansoni in a population of Biomphalaria tenagophila (D'Orbigny, 1835) in the region of "Vale do Ribeira de Iguape", Brazil

Guimaraes¹,

Muniz²,

Takahashi³

et al. 2010

Rev. Inst. Med. trop. S. Paulo

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SUMMARYTo observe the effects of the parasitic infection on the biology of B. tenagophila, field and laboratory populations of this mollusk from Itariri, in Vale do Ribeira, Brazil, were experimentally infected. Each mollusk received 10 miracidia of Schistosoma mansoni (SJ lineage) and was observed throughout the parasite's development. The biological variables were compared according to the criteria "group" and "infectious phase". The main damage caused by the parasitic infection manifested itself in reproduction, longevity and lesions on the shell of the mollusks in the patent phase. An infection rate of 58.8% was observed. Microanatomical study of the mollusk's digestive gland and ovotestis revealed the presence of evolving larval forms and cercariae. It was concluded that the effects of the parasitic infection on both populations were moderate, despite the low survival rate of the infected mollusks, the damage did not prevent either reproduction or the elimination of cercariae, which continued for a long time.

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“…These strict associations have allowed specialised interactions to evolve, including parasite‐induced alterations in host behaviour, defence function, nutrition, metabolism and reproduction [2–4]. One common outcome of digenean infection in molluscs is castration [5–8], which can result in the incomplete or total disruption of host gamete production and presumably allow for the redeployment of metabolites to the parasite [9].…”

Section: Introductionmentioning

confidence: 99%

“…In infected abalone, the sporocyst and cercarial stages inhabit the haemocoel suggesting that parasitic castration is likely to be because of effects to the physiology of the host and not direct consumption of the gonad by the trematode. Infections of other host molluscs largely appear to follow similar patterns of castration [5–7]. In this study, we have quantitatively assessed the expression of 10 transcription factor genes, along with FMRFamide, prohormone convertase 2 (PC2), and tubulin genes in the cerebral and pleuropedal ganglia of H. asinina that are either: (i) actively reproducing; (ii) parasitized and castrated; and (iii) not reproducing.…”

Section: Introductionmentioning

confidence: 99%

Parasitic castration by the digenian trematode Allopodocotyle sp. alters gene expression in the brain of the host mollusc Haliotis asinina

et al. 2006

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Infection of molluscs by digenean trematode parasites typically results in the repression of reproduction -the so-called parasitic castration. This is known to occur by altering the expression of a range of host neuropeptide genes. Here we analyse the expression levels of 10 members of POU, Pax, Sox and Hox transcription factor gene families, along with genes encoding FMRFamide, prohormone convertase and b-tubulin, in the brain ganglia of actively reproducing (summer), non-reproducing (winter) and infected Haliotis asinina (a vetigastropod mollusc). A number of the regulatory genes are differentially expressed in parasitised H. asinina, but in only a few cases do expression patterns in infected animals match those occurring in animals where reproduction is normally repressed.

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Studies on parasitic castration: Occurrence of a gametogenesis-inhibiting factor in extract of Zoogonus lasius (Trematoda)

Cited by 24 publications

References 13 publications

Reduction of testis growth of pseudaletia separata larvae after parasitization by cotesia kariyai

Reduction of testis growth of pseudaletia separata larvae after parasitization by cotesia kariyai

The effects of the experimental infection from a focus of transmission of Schistosoma mansoni in a population of Biomphalaria tenagophila (D'Orbigny, 1835) in the region of "Vale do Ribeira de Iguape", Brazil

Parasitic castration by the digenian trematode Allopodocotyle sp. alters gene expression in the brain of the host mollusc Haliotis asinina

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