The Influence of Human Skin Lipids on the Cercarial Penetration Responses of Schistosoma haematobium and Schistosoma mansoni

Shiff, Clive; Cmelik, S; Ley, Helga; Kriel, Robert L.

doi:10.2307/3278192

Cited by 50 publications

(25 citation statements)

References 11 publications

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“…Biting by mosquitoes of humans is not random, and attractiveness may be related to sex, skin surface area (hence age), and other factors (25,(44)(45)(46)(47)(48). Susceptibility to schistosome infection varies with the nature of contacts (31,49), possibly with skin thickness and lipid content (50,51) and may be related to genetic factors (52). Risk of STD transmission is affected by the frequency and type of sexual acts and by cofactors (53,54).…”

Section: Discussionmentioning

confidence: 99%

Heterogeneities in the transmission of infectious agents: Implications for the design of control programs

Woolhouse

Dye²,

Etard³

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

1,042

1,017

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From an analysis of the distributions of measures of transmission rates among hosts, we identify an empirical relationship suggesting that, typically, 20% of the host population contributes at least 80% of the net transmission potential, as measured by the basic reproduction number, R 0 . This is an example of a statistical pattern known as the 20͞80 rule. The rule applies to a variety of disease systems, including vector-borne parasites and sexually transmitted pathogens. The rule implies that control programs targeted at the ''core'' 20% group are potentially highly effective and, conversely, that programs that fail to reach all of this group will be much less effective than expected in reducing levels of infection in the population as a whole.

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Section: Discussionmentioning

confidence: 99%

Heterogeneities in the transmission of infectious agents: Implications for the design of control programs

Woolhouse

Dye²,

Etard³

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

1,042

1,017

View full text Add to dashboard Cite

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“…In Schistosoma mansoni and S. haematobium, the emptying of penetration glands is induced by unsaturated fatty acids such as linoleic and linolenic acids (e.g. MacInnis 1969; Shiff et al 1972;Austin et al 1972Austin et al , 1974. In in vitro experiments, lipids from human skin surface fractions stimulated predominantly emptying of circumacetabular glands, whereas hydrophilic extracts stimulated mainly the secretion of postacetabular glands in S. mansoni.…”

Section: Introductionmentioning

confidence: 98%

In vitro stimulation of penetration gland emptying by Trichobilharzia szidati and T. regenti (Schistosomatidae) cercariae. Quantitative collection and partial characterization of the products

et al. 2005

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Induction of penetration gland emptying by cercariae of the bird schistosomes Trichobilharzia szidati and T. regenti employing linoleic acid, linolenic acid, praziquantel and calcium ionophore A23187 showed that both postacetabular and circumacetabular cells released their content at chosen stimulant concentrations. The gland secretions consisted of soluble and insoluble parts. The former one adhering to the ground seemed to have different saccharide composition from the glands of Schistosoma mansoni. It bound labelled saccharides, thus exhibiting lectin-like activity. Protein profiles of the latter one were identical after stimulation by all four stimulants in T. szidati. The soluble secretions contained several proteolytic enzymes; 31 kDa and 33 kDa cysteine proteases were identified in E/S products of T. szidati and T. regenti, respectively. The circumacetabular glands contained a significant amount of calcium. Immunohistochemistry revealed that the origin of E/S products after in vitro stimulation is in both penetration glands and tegumental structures. No crossreactivity was observed between the bird schistosomes and a serum raised against S. mansoni elastase.

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“…These cercarial secretions (CSs) contain proteases, the release of which is stimulated by fatty acids normally found on human skin (Shiff et al 1972). One of the predominant proteins in the CSs is cercarial elastase (CE).…”

Section: Introductionmentioning

confidence: 99%

Biochemical comparison of the serine protease (elastase) activities in cercarial secretions from Trichobilharzia ocellata and Schistosoma mansoni

Bahgat

Ruppel

2002

Parasitol Res

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We report on serine protease activity in cercarial secretions (CSs) from the bird parasite Trichobilharzia ocellata. Using a colorigenic substrate, the biochemical properties of this enzyme were studied and its activity was compared to the homologous one in CSs from the human parasite Schistosoma mansoni. The specific serine protease activity was always 2- to 3-fold higher in CSs from T. ocellatacompared to S. mansoni. The enzyme has its optimal activity at pH 10.5, is Ca2+-dependent (inhibition with EDTA) and has a trypsin-like (inhibition with anti-pain) serine proteinase activity (inhibition with PMSF and aprotinin). The K(m) value of the serine protease from T. ocellatawas higher than that of S. mansoni, and the K(i) values for several inhibitors were generally lower for the enzyme of T. ocellatathan that of S. mansoni except for EDTA. The enzyme activities from both parasites had a molecular weight of 30 kDa in gelatin-SDS-polyacrylamide gels. The intensity of the gelatin digestion bands was stronger with the T. ocellata than with the S. mansoni enzyme.

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The Influence of Human Skin Lipids on the Cercarial Penetration Responses of Schistosoma haematobium and Schistosoma mansoni

Cited by 50 publications

References 11 publications

Heterogeneities in the transmission of infectious agents: Implications for the design of control programs

Heterogeneities in the transmission of infectious agents: Implications for the design of control programs

In vitro stimulation of penetration gland emptying by Trichobilharzia szidati and T. regenti (Schistosomatidae) cercariae. Quantitative collection and partial characterization of the products

Biochemical comparison of the serine protease (elastase) activities in cercarial secretions from Trichobilharzia ocellata and Schistosoma mansoni

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