Vignette d'image

Guerin, Patrick

Nom
Guerin, Patrick
Affiliation principale
Fonction
Ancien.ne collaborateur.trice
Identifiants
https://libra.unine.ch/handle/123456789/310
_
0000-0002-2257-5097

Résultat de la recherche

Filtres

1
5
5
41
Réinitialiser les filtres

Paramètres

Voici les éléments 1 - 5 sur 5
  • Publication
    Accès libre
    Etude des facteurs déclenchant le comportement sexuel chez Ixodes ricinus L. et de la physiologie de ses sensilles gustatives
    (2002)
    Grenacher, Stoyan
    ;
    Guerin, Patrick 
    Abstract. Ticks are ectoparasites of vertebrates and utilize a variety of infochemicals for host finding and acceptance as well as for intraspecific aggregation and mating responses. Individual male and female Ixodes ricinus, the vector of Lyme disease in Europe, readily arrest on filter paper strips contaminated with their own faeces. I. ricinus also responds, but to a lesser degree, to faeces-contaminated papers enclosed in metal mesh envelopes, i.e. without directly contacting the faeces, suggesting a role for volatiles in the arrestment response. The faecal constituents guanine, xanthine, uric acid and 8-azaguanine (a bacterial breakdown product of guanine) also caused arrestment of individual I. ricinus males and females. However, mixtures of these products induced arrestment of I. ricinus at doses one hundred fold lower than the lowest active dose of any of them tested singly. Saline extracts of faeces activated receptor cells in terminal pore sensilla on the first leg tarsi of I. ricinus. One cell in these sensilla responded in a similar dose dependent manner to guanine and 8-azaguanine, whereas a second cell was more sensitive to lower doses of 8-azaguanine. The response threshold approached 100 fM for both cells. These findings suggest that faeces and faecal breakdown products are implicated in aggregation responses of I. ricinus. This may account for the clumped distribution of this ectoparasite on the ground and contribute to the high proportion of mated individuals recorded prior to host colonization.
  • Publication
    Accès libre
    Behavioural and chemoreceptor cell responses of the tick, Ixodes ricinus, to its own faeces and faecal constituents
    (Springer, 2001)
    Grenacher, Stoyan
    ;
    Kröber, Thomas
    ;
    Guerin, Patrick 
    ;
    Vlimant, Michèle 
    Ticks are ectoparasites of vertebrates and utilize a variety ofinfochemicals for host finding and acceptance as well as for intraspecific aggregation and mating responses. Individual male and female Ixodes ricinus, the vector of Lyme disease in Europe, readily arrest onfilter paper strips contaminated with their own faeces. I. ricinus also responds, but to a lesser degree, tofaeces-contaminated papers enclosed in metal mesh envelopes, i.e. without directly contacting the faeces, suggesting a role for volatiles in the arrestment response. The faecal constituents guanine, xanthine, uric acid and 8-azaguanine (a bacterial breakdown product of guanine) also caused arrestment of individual I.ricinus males and females. However, mixtures of these products induced arrestment of I. ricinus at doses one hundred fold lower than the lowest active dose of any of them tested singly. Saline extracts of faeces activated receptor cells in terminal pore sensilla on the first legtarsi of I. ricinus. One cell in these sensilla responded in a similar dose dependent manner to guanine and 8-azaguanine, whereas a second cell was more sensitive to lower doses of 8-azaguanine. The response threshold approached 100 fM for both cells. These findings suggest that faeces and faecal breakdown products are implicated in aggregation responses of I. ricinus. This may account for the clumped distribution of this ectoparasite on the ground and contribute to the high proportion of mated individuals recorded prior to host colonization.
  • Publication
    Accès libre
    Chemosensory and behavioural adaptations of ectoparasitic arthropods
    (2000)
    Guerin, Patrick 
    ;
    Kroeber, Thomas 
    ;
    McMahon, Conor
    ;
    Guerenstein, Pablo
    ;
    Grenacher, Stoyan
    ;
    Vlimant, Michèle 
    ;
    Diehl, Peter-Allan 
    ;
    Steullet, Pascal
    ;
    Syed, Zainulabeudin
  • Publication
    Accès libre
    Chemsensory and Behavioural Adaptations of Ectoparasitic Arthropods
    (2000)
    Guerin, Patrick 
    ;
    Kröber, Thomas
    ;
    McMahon, Conor
    ;
    Guerenstein, Pablo
    ;
    Grenacher, Stoyan
    ;
    Vlimant, Michèle 
    ;
    Diehl, Peter-Allan 
    ;
    Steullet, Pascal
    ;
    Syed, Zainulabeudin
  • Publication
    Accès libre
    Inadvertent introduction of squalene, cholesterol, and other skin products into a sample
    (1994)
    Grenacher, Stoyan
    ;
    Guerin, Patrick 
    Recent developments in analytical techniques permit the chemical ecologist to achieve identification of naturally occurring compounds with relatively small amounts of the products of interest. However, the microanalytical techniques employed frequently require the handling of sample vials and other transferral instruments such as syringes and micropipets, where the analyst's hands come into close contact with the sample. Here we show how inadvertent contamination of a sample with skin lipids can occur simply by catching a 1-ml sample vial by the neck rather than the base or by activating a syringe by holding the plunger extension between the fingers rather than taking it by the head. Squalene, cholesterol, and, to a lesser extent, hydrocarbons and fatty acids from fingers are easily introduced into the sample in this manner. These findings are particularly relevant for a parasitology laboratory such as ours, investigating the function of vertebrate-derived products in hematophagous arthropods.