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Demar Taylor - One of the best experts on this subject based on the ideXlab platform.
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characterization of a vitellogenin gene reveals two phase regulation of vitellogenesis by engorgement and mating in the soft tick ornithodoros moubata acari argasidae
Insect Molecular Biology, 2010Co-Authors: T Shinoda, Mari Horigane, Hiroshi Honda, Demar TaylorAbstract:Synthesis of the precursor yolk protein vitellogenin (Vg) occurs after engorgement in haematophagous arthropods. We identified the Vg cDNA of the soft tick Ornithodoros moubata (OmVg) and compared its expression in mated and Virgin Females. Both mated and Virgin Females showed increases in OmVg expression after engorgement but expression was higher in mated Females than Virgin Females particularly as time advanced. Delayed mating in Virgin Females induced an increase in OmVg expression. OmVg expression was observed in the midgut and fat body by whole mount in situ hybridization, but enlarged fat body with high expression occurred in only mated Females during the late phase of vitellogenesis. Therefore, engorgement initially induces OmVg expression but mating is necessary for continued Vg expression to produce mature eggs.
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ecdysteroid hormone titer and its relationship to vitellogenesis in the soft tick ornithodoros moubata acari argasidae
General and Comparative Endocrinology, 2007Co-Authors: Kazumasa Ogihara, Yoshiro Nakajima, Mari Horigane, Atsuko Moribayashi, Demar TaylorAbstract:A blood meal is required for reproduction in most argasid female ticks. The blood meal appears to stimulate an organ in the posterior end to produce a fat body stimulating factor (FSF), which is thought to be an ecdysteroid, to induce vitellogenin (Vg) synthesis. In this study, the relationship of vitellogenesis and ecdysteroids was investigated by measuring Vg and ecdysteroid titers while observing oocyte development and oviposition in mated and Virgin Females. Oviposition occurred from day 10 after engorgement in mated Females and continued up to 40-50 days, whereas egg maturation and oviposition did not occur in Virgin Females. Vg titers in the hemolymph peaked on day 6 after engorgement and subsequently declined in mated Females. Interestingly, Vg synthesis occurred and ovarian development progressed to the development of early vitellogenic oocytes in Virgin Females but oocyte maturation and oviposition did not occur. Topical application of ecdysteroids induced oviposition in fed Virgin Females indicating that ecdysteroids may induce oviposition. Concentrations of ecdysteroids for 20 days after engorgement revealed several peaks in mated female whole body extracts, but no peaks in Virgin female extracts. In the hemolymph of only mated Females, ecdysteroid titers showed two peaks that followed the early peak of ecdysteroids in the whole body on day 4 and 6 after engorgement. In addition, ecdysteroids in the reproductive tissues increased with the development of the ovary in mated Females and this increase coincided with the latter peaks of the whole body. These observations indicate that physiological elevation of ecdysteroids accelerate Vg synthesis, and may induce egg maturation and stimulate oviposition in fed mated Ornithodoros moubata Females.
Mari Horigane - One of the best experts on this subject based on the ideXlab platform.
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characterization of a vitellogenin gene reveals two phase regulation of vitellogenesis by engorgement and mating in the soft tick ornithodoros moubata acari argasidae
Insect Molecular Biology, 2010Co-Authors: T Shinoda, Mari Horigane, Hiroshi Honda, Demar TaylorAbstract:Synthesis of the precursor yolk protein vitellogenin (Vg) occurs after engorgement in haematophagous arthropods. We identified the Vg cDNA of the soft tick Ornithodoros moubata (OmVg) and compared its expression in mated and Virgin Females. Both mated and Virgin Females showed increases in OmVg expression after engorgement but expression was higher in mated Females than Virgin Females particularly as time advanced. Delayed mating in Virgin Females induced an increase in OmVg expression. OmVg expression was observed in the midgut and fat body by whole mount in situ hybridization, but enlarged fat body with high expression occurred in only mated Females during the late phase of vitellogenesis. Therefore, engorgement initially induces OmVg expression but mating is necessary for continued Vg expression to produce mature eggs.
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ecdysteroid hormone titer and its relationship to vitellogenesis in the soft tick ornithodoros moubata acari argasidae
General and Comparative Endocrinology, 2007Co-Authors: Kazumasa Ogihara, Yoshiro Nakajima, Mari Horigane, Atsuko Moribayashi, Demar TaylorAbstract:A blood meal is required for reproduction in most argasid female ticks. The blood meal appears to stimulate an organ in the posterior end to produce a fat body stimulating factor (FSF), which is thought to be an ecdysteroid, to induce vitellogenin (Vg) synthesis. In this study, the relationship of vitellogenesis and ecdysteroids was investigated by measuring Vg and ecdysteroid titers while observing oocyte development and oviposition in mated and Virgin Females. Oviposition occurred from day 10 after engorgement in mated Females and continued up to 40-50 days, whereas egg maturation and oviposition did not occur in Virgin Females. Vg titers in the hemolymph peaked on day 6 after engorgement and subsequently declined in mated Females. Interestingly, Vg synthesis occurred and ovarian development progressed to the development of early vitellogenic oocytes in Virgin Females but oocyte maturation and oviposition did not occur. Topical application of ecdysteroids induced oviposition in fed Virgin Females indicating that ecdysteroids may induce oviposition. Concentrations of ecdysteroids for 20 days after engorgement revealed several peaks in mated female whole body extracts, but no peaks in Virgin female extracts. In the hemolymph of only mated Females, ecdysteroid titers showed two peaks that followed the early peak of ecdysteroids in the whole body on day 4 and 6 after engorgement. In addition, ecdysteroids in the reproductive tissues increased with the development of the ovary in mated Females and this increase coincided with the latter peaks of the whole body. These observations indicate that physiological elevation of ecdysteroids accelerate Vg synthesis, and may induce egg maturation and stimulate oviposition in fed mated Ornithodoros moubata Females.
Koji Tojo - One of the best experts on this subject based on the ideXlab platform.
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Potential for parthenogenesis of Virgin Females in a bisexual population of the geographically parthenogenetic mayfly Ephoron shigae (Insecta: Ephemeroptera, Polymitarcyidae)
Biological Journal of The Linnean Society, 2009Co-Authors: Kazuki Sekiné, Koji TojoAbstract:The burrowing polymitarcyid mayfly Ephoron shigae is a geographically parthenogenetic species. Interestingly, the distributions of the bisexual and unisexual populations overlap broadly in their respective geographic ranges. In this mayfly, obligatory diploid thelytoky appears within unisexual populations. In the present study, we examined the potential for parthenogenesis or the parthenogenetic ability of Females in a bisexual population aiming to understand the emergence of unisexual populations. The results obtained revealed that Females in the examined bisexual populations showed a potential for diploid thelytoky as also seen in the unisexual populations, although, in Females from bisexual populations, the development success rates of their unfertilized eggs were considerably lower than those of Virgin Females from unisexual populations. In the three bisexual reproducing species (Ephemera japonica, Ephemera strigata, and Ephemera orientalis) in the closely-related family Ephemeridae, diploid thelytoky (i.e. tychoparthenogenesis;
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potential for parthenogenesis of Virgin Females in a bisexual population of the geographically parthenogenetic mayfly ephoron shigae insecta ephemeroptera polymitarcyidae
Biological Journal of The Linnean Society, 2009Co-Authors: Kazuki Sekiné, Koji TojoAbstract:The burrowing polymitarcyid mayfly Ephoron shigae is a geographically parthenogenetic species. Interestingly, the distributions of the bisexual and unisexual populations overlap broadly in their respective geographic ranges. In this mayfly, obligatory diploid thelytoky appears within unisexual populations. In the present study, we examined the potential for parthenogenesis or the parthenogenetic ability of Females in a bisexual population aiming to understand the emergence of unisexual populations. The results obtained revealed that Females in the examined bisexual populations showed a potential for diploid thelytoky as also seen in the unisexual populations, although, in Females from bisexual populations, the development success rates of their unfertilized eggs were considerably lower than those of Virgin Females from unisexual populations. In the three bisexual reproducing species (Ephemera japonica, Ephemera strigata, and Ephemera orientalis) in the closely-related family Ephemeridae, diploid thelytoky (i.e. tychoparthenogenesis; < 3%) was also observed. However, in this case, the parthenogenetic development success rates of unfertilized eggs were significantly lower than those of Virgin Females in the bisexual (Hino-yosui Irrigation Canal) population of E. shigae. Accordingly, we suggest that parthenogenetic ability (i.e. tychoparthenogenesis or facultative parthenogenesis) in bisexual populations of E. shigae may facilitate the evolutionary transition to unisexual populations with fully obligatory parthenogenesis. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 326–334.
Angel Guerrero - One of the best experts on this subject based on the ideXlab platform.
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behavioral responses ofspodoptera littoralis males to sex pheromone components and Virgin Females in wind tunnel
Journal of Chemical Ecology, 1996Co-Authors: Carmen Quero, Philippe Lucas, Michel Renou, Angel GuerreroAbstract:The major component of the sex pheromone of Femalespodoptera littoralis, (Z,E)-9,11-tetradecadienyl acetate (1), elicited all steps of the male behavioral sequence, i.e., wing fanning and taking flight, oriented upwind flight and arrival to the middle of the tunnel, close approach and contact with the source. The activity was equivalent to that elicited by Virgin Females. In the range of doses tested, the dosage of1 had no significant effect on the number of source contacts. Male response was significantly affected by light intensity, being optimum at 3 lux. Activity of the minor components (Z)-9-tetradecenyl acetate (2), (E)-11-tetradecenyl acetate (3), tetradecyl acetate (4), (Z)-11-tetradecenyl acetate (5), and (Z,E)-9,12-tetradecadienyl acetate (6) was significantly lower than that of the major component when assayed individually. In multicomponent blends compound4 appeared to strongly decrease the number of males arrested at the source, the effect being particularly important when compound5 was present in the blend. Results of single sensillum experiments confirmed the existence of two main physiologically distinct sensillar types. The most common type of sensilla contained a neuron that responded specifically to compound1. A second type of sensilla, located laterally on the ventral sensory surface, contained two receptor neurons responding to compound6 and to (Z)-9-tetradecenol. Among short sensilla, one hair responded to compound4 and could represent a minor sensillar type. No sensory neuron was found to detect the other minor pheromone compounds2, 3, and5.
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Behavioral responses of Spodoptera littoralis males to sex pheromone components and Virgin Females in wind tunnel
Journal of Chemical Ecology, 1996Co-Authors: Carmen Quero, Philippe Lucas, Michel Renou, Angel GuerreroAbstract:The major component of the sex pheromone of female Spodoptera littoralis, (Z,E)-9,11-tetradecadienyl acetate (1), elicited all steps of the male behavioral sequence, i.e., wing fanning and taking flight, oriented upwind flight and arrival to the middle of the tunnel, close approach and contact with the source. The activity was equivalent to that elicited by Virgin Females. In the range of doses tested, the dosage of 1 had no significant effect on the number of source contacts. Male response was significantly affected by light intensity, being optimum at 3 lux. Activity of the minor components (Z)-9-tetradecenyl acetate (2), (E)-11-tetradecenyl acetate (3), tetradecyl acetate (4), (Z)-11-tetradecenyl acetate (5), and (Z,E)-9,12-tetradecadienyl acetate (6) was significantly lower than that of the major component when assayed individually. In multicomponent blends compound 4 appeared to strongly decrease the number of males arrested at the source, the effect being particularly important when compound 5 was present in the blend. Results of single sensillum experiments confirmed the existence of two main physiologically distinct sensillar types. The most common type of sensilla contained a neuron that responded specifically to compound1. A second type of sensilla, located laterally on the ventral sensory surface, contained two receptor neurons responding to compound 6 and to (Z)-9-tetradecenol. Among short sensilla, one hair responded to compound 4 and could represent a minor sensillar type. No sensory neuron was found to detect the other minor pheromone compounds 2, 3, and 5.
Kazumasa Ogihara - One of the best experts on this subject based on the ideXlab platform.
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ecdysteroid hormone titer and its relationship to vitellogenesis in the soft tick ornithodoros moubata acari argasidae
General and Comparative Endocrinology, 2007Co-Authors: Kazumasa Ogihara, Yoshiro Nakajima, Mari Horigane, Atsuko Moribayashi, Demar TaylorAbstract:A blood meal is required for reproduction in most argasid female ticks. The blood meal appears to stimulate an organ in the posterior end to produce a fat body stimulating factor (FSF), which is thought to be an ecdysteroid, to induce vitellogenin (Vg) synthesis. In this study, the relationship of vitellogenesis and ecdysteroids was investigated by measuring Vg and ecdysteroid titers while observing oocyte development and oviposition in mated and Virgin Females. Oviposition occurred from day 10 after engorgement in mated Females and continued up to 40-50 days, whereas egg maturation and oviposition did not occur in Virgin Females. Vg titers in the hemolymph peaked on day 6 after engorgement and subsequently declined in mated Females. Interestingly, Vg synthesis occurred and ovarian development progressed to the development of early vitellogenic oocytes in Virgin Females but oocyte maturation and oviposition did not occur. Topical application of ecdysteroids induced oviposition in fed Virgin Females indicating that ecdysteroids may induce oviposition. Concentrations of ecdysteroids for 20 days after engorgement revealed several peaks in mated female whole body extracts, but no peaks in Virgin female extracts. In the hemolymph of only mated Females, ecdysteroid titers showed two peaks that followed the early peak of ecdysteroids in the whole body on day 4 and 6 after engorgement. In addition, ecdysteroids in the reproductive tissues increased with the development of the ovary in mated Females and this increase coincided with the latter peaks of the whole body. These observations indicate that physiological elevation of ecdysteroids accelerate Vg synthesis, and may induce egg maturation and stimulate oviposition in fed mated Ornithodoros moubata Females.
