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Guerin, Patrick

Nom
Guerin, Patrick
Affiliation principale
Site web
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Professeur associƩ
Email
patrick.guerin@unine.ch
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https://libra.unine.ch/handle/123456789/310

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  • Publication
    AccĆØs libre
    Ultrastructure and receptor cell responses of the antennal grooved peg sensilla of Triatoma infestans (Hemiptera : Reduviidae)
    (2003)
    Diehl, Peter-Allan 
    ;
    Vlimant, MichĆØle 
    ;
    Guerenstein, Pablo
    ;
    Guerin, Patrick 
    Ultrastructural examination of grooved-peg (GP) sensilla on the antenna of fifth instar Triatoma infestans nymphs by scanning electron microscopy and transmission electron microscopy reveal that they are 8-18 mum long with a diameter of about 2-2.8 mum at the non-articulated base. Some pegs have a terminal pore. These double-walled wall-pore (dw-wp) sensilla have an outer cuticular wall with 13-18 longitudinal grooves at the distal part of the peg. Groove channels are present at the bottom of the grooves from which radial spoke channels lead into the inner sensillum-lymph cavity. A dendrite sheath connects the tip of the thecogen cell to the inner cuticular wall thus forming separated outer and inner sensillum-lymph cavities. Four or five bipolar receptor cells are ensheathed successively within the GP sensilla by the thecogen cell, trichogen and tormogen cells. The inner dendritic segments of each sensory cell give rise at the ciliary constriction to an unbranched outer dendritic segment which can reach the tip of the sensillum. Electrophysiological recordings from the GP sensilla indicate that they house NH3, short-chain carboxylic acid and short-chain aliphatic amine receptor cells and can be divided into three functional sub-types (GP 1-3). All GP sensilla carry a receptor cell excited by aliphatic amines, such as isobutylamine, a compound associated with vertebrate odour. GP type 1 and 2 sensilla house, in addition, an NH3-excited cell whereas the type 2 sensilla also contains a short-chain carboxylic acid receptor. No cell particularly sensitive to either NH3 or carboxylic acids was found in the grooved-peg type 3 sensilla. GP types 1, 2 and 3 represent ca. 36, 10 and 43% of the GP sensilla, respectively, whereas the remaining 11% contain receptor cells that manifest normal spontaneous activity but do not respond to any of the afore mentioned stimuli. (C) 2003 Elsevier Science Ltd. All rights reserved.
  • Publication
    AccĆØs libre
    Ultrastructure and receptor cell responses of the antennal grooved peg sensilla of Triatoma infestans (Hemiptera: Reduviidae)
    (2003)
    Diehl, Peter-Allan 
    ;
    Vlimant, MichĆØle 
    ;
    Guerenstein, Pablo
    ;
    Guerin, Patrick 
    Ultrastructural examination of grooved-peg (GP) sensilla on the antenna of fifth instar Triatoma infestans nymphs by scanning electron microscopy and transmission electron microscopy reveal that they are 8ā€“18 Ī¼m long with a diameter of about 2ā€“2.8 Ī¼m at the non-articulated base. Some pegs have a terminal pore. These double-walled wall-pore (dw-wp) sensilla have an outer cuticular wall with 13ā€“18 longitudinal grooves at the distal part of the peg. Groove channels are present at the bottom of the grooves from which radial spoke channels lead into the inner sensillum-lymph cavity. A dendrite sheath connects the tip of the thecogen cell to the inner cuticular wall thus forming separated outer and inner sensillum-lymph cavities. Four or five bipolar receptor cells are ensheathed successively within the GP sensilla by the thecogen cell, trichogen and tormogen cells. The inner dendritic segments of each sensory cell give rise at the ciliary constriction to an unbranched outer dendritic segment which can reach the tip of the sensillum.

    Electrophysiological recordings from the GP sensilla indicate that they house NH3, short-chain carboxylic acid and short-chain aliphatic amine receptor cells and can be divided into three functional sub-types (GP 1ā€“3). All GP sensilla carry a receptor cell excited by aliphatic amines, such as isobutylamine, a compound associated with vertebrate odour. GP type 1 and 2 sensilla house, in addition, an NH3-excited cell whereas the type 2 sensilla also contains a short-chain carboxylic acid receptor. No cell particularly sensitive to either NH3 or carboxylic acids was found in the grooved-peg type 3 sensilla. GP types 1, 2 and 3 represent ca. 36, 10 and 43% of the GP sensilla, respectively, whereas the remaining 11% contain receptor cells that manifest normal spontaneous activity but do not respond to any of the afore mentioned stimuli.
  • Publication
    AccĆØs libre
    Darkness induces mobility, and saturation deficit limits questing duration, in the tick Ixodes ricinus
    (2003)
    Perret, Jean-Luc
    ;
    Guerin, Patrick 
    ;
    Diehl, Peter-Allan 
    ;
    Vlimant, MichĆØle 
    ;
    Gern, Lise 
    The behaviour of Ixodes ricinus nymphs was recorded in 10-day experiments using computer-assisted video-tracking, in the absence of any host stimuli. These ticks switch spontaneously from questing in a desiccating atmosphere to quiescence in a water-saturated atmosphere after dark. Quantification of both questing and quiescence duration demonstrates that questing duration is inversely related to saturation deficit whereas quiescence duration is not. Distance walked after quiescence increased with desiccating conditions, while the distance walked after questing remained unchanged. Almost all locomotor activities of I. ricinus occurred during darkness under either a 14 h:10 h L:D or a 8 h:4 h L:D cycle. We established that all life stages of I. ricinus are equipped to sense shifts in light intensity with bilaterally placed strings of photoreceptors. This permits I. ricinus to use onset of darkness to trigger mobility when desiccation risk is reduced in nature.
  • Publication
    AccĆØs libre
    Chemsensory and Behavioural Adaptations of Ectoparasitic Arthropods
    (2000)
    Guerin, Patrick 
    ;
    Krƶber, Thomas
    ;
    McMahon, Conor
    ;
    Guerenstein, Pablo
    ;
    Grenacher, Stoyan
    ;
    Vlimant, MichĆØle 
    ;
    Diehl, Peter-Allan 
    ;
    Steullet, Pascal
    ;
    Syed, Zainulabeudin
  • Publication
    AccĆØs libre
    Chemosensory and behavioural adaptations of ectoparasitic arthropods
    (2000)
    Guerin, Patrick 
    ;
    Kroeber, Thomas 
    ;
    McMahon, Conor
    ;
    Guerenstein, Pablo
    ;
    Grenacher, Stoyan
    ;
    Vlimant, MichĆØle 
    ;
    Diehl, Peter-Allan 
    ;
    Steullet, Pascal
    ;
    Syed, Zainulabeudin
  • Publication
    AccĆØs libre
    Biosynthesis, production site, and emission rates of aggregation-attachment pheromone in males of two Amblyomma ticks
    (1991)
    Diehl, Peter-Allan 
    ;
    Guerin, Patrick 
    ;
    Vlimant, MichĆØle 
    ;
    Steullet, Pascal
    The aggregation-attachment pheromone componentso-nitrophenol (ONP) and methyl salicylate (MS) in male Amblyomma variegatum ticks appeared after three days of feeding on the host and reached high values after about six days. Variable quantities of 1.3ā€“7.3 Ī¼g ONP and about 0.6 Ī¼g MS were present within ticks. ONP and MS were released at the high rates of 300ā€“1800 ng/hr and 20ā€“600 ng/hr per male tick, respectively. After a temporary decrease, males continued to emit at high rates after nearby attachment of females. In A. hebraeum, ONP showed a similar pattern, but with a delay of about a day. A male, which had fed during 14 days, contained about 2 Ī¼g and released 225ā€“280 ng/hr. Emission in forcibly detached males of both species dropped rapidly to low levels of less than 10 ng/hr per tick. Host skin and tick feces in the vicinity of feeding males were pheromoneimpregnated. The very high emission rates are consistent with the observations that the pheromone is an important component of the host-location mechanism of conspecifics. ONP and MS are produced in the dermal glands type 2 associated with the ventrolateral cuticle.