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1
Oehninger-Storvoll, Karen-Christine. "Stress influence of offshore wind farms on the reproduction of the viviparous eelpout (Zoarces viviparus)." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21415.
Full textAbstract:
Okende behov for fornybar energi har skapt en økning av installasjoner for fornybar marin energi. Disse installasjonene varierer fra bølge- og tidevannskraft til offshore vindkraft. Påvirkning av offshore vindkraft på fiskearten ålekvabbe (<i>Zoarces viviparus</i>) i Ostersjøen har blitt undersøkt i denne studien. I løpet av to feltsesonger (oktober 2011 og 2012) ble gravide hunnfisk fanget ved Lillgrund vindkraftpark (Breddegrad 55°, lengdegrad 12°.), samt ved en kontrollokaliten Bredgrund. Fiskens lengde (TL), totalvekt, gonade- og levervekt ble målt samt antall yngel, lengde på yngel, kjønnsfordeling og yngelens overlevelse ble registrert. Resultatene viser at hunner fra vindkraftparken er i bedre kondisjon og har fler samt større yngel enn i kontrollokaliteten. Denne studien viser også hvordan år kan påvirke alle disse trekkene og hvordan det gjør det viktig å ha data fra flere år samt lokaliteter i fremtidige studier når påvirkninger av vindkraft skal bedømmes.
2
Robert, Kylie. "Temperature-dependent sex determination in the viviparous lizard, Eulamprus tympanum." Connect to full text, 2003. http://hdl.handle.net/2123/557.
Full textAbstract:
Thesis (Ph. D.)--University of Sydney, 2004.Title from title screen (viewed 5 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Degree awarded 2004; thesis submitted 2003. Appendices contains published articles co-authored by Robert. Includes bibliographical references. Also available in print form.
3
Robert, Kylie Anne. "Temperature-dependent sex determination in the viviparous lizard Eulamprus tympanum." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/557.
Full textAbstract:
Abstract There are a remarkable variety of sex determination systems among different animal taxa. In most animals, sex is determined chromosomally. Although in an increasing number of animals sex determination has been found to be influenced primarily by the environment. Species with genotypic sex determination (GSD) have their sex determined at the time of fertilization, by genetic factors alone and those with environmental sex determination (ESD) have their sex determined by environmental factors that act after fertilization. Temperature-dependent Sex Determination (TSD), whereby the sex of the developing embryos depends on the temperature at which they develop is widespread in oviparous reptiles and occurs in all crocodilians, marine turtles and tuatara examined to date and is common in many freshwater turtles and lizards. SECTION ONE Temperature-dependent sex determination (TSD) was never expected to occur in viviparous reptiles, as thermoregulation by pregnant females would result in relatively stable gestation temperatures. Temperature-dependent sex determination and viviparity goes against all the basic assumptions that TSD occurs in oviparous reptiles where temperatures within a nest vary widely. However, skewed sex ratios as a result of incubation temperature indicated the possibility of TSD in the viviparous lizard Eulamprus tympanum. In my first experiments I show the first recorded case of a viviparous reptile with TSD. The developing embryos of the viviparous skink E. tympanum are subject to TSD, with gestation temperature having a highly significant effect on sex and warmer temperatures giving rise to male offspring (Chapter 1). Sex is fully determined at the time of birth and can be differentiated histologically into testes or ovaries (Chapter 2). The morphology and histological characteristics of the gonads of neonatal E. tympanum resulting from the treatment temperatures described in chapter 1 illustrate that sex in E. tympanum is easily distinguished at the time of birth and corresponds with the presence or absence of hemipenes. Males are histologically characterised by an elongated gonad consisting of seminiferous tubules with either no cortical epithelium or, if present at all, in a very thin band. If they are present, Mϋllerian ducts, showing signs of degeneration, are attached to the kidney by a shortened mesosalpinx. Females are histologically characterised by an irregularly shaped gonad consisting of a thick cortical epithelium that occasionally contains oocytes. The Mϋllerian ducts are obvious structures attached to the kidney by a fibrous mesosalpinx. The presence or absence of hemipenes is a reliable technique for determining sex in newborn E. tympanum. Sex determination is easiest to perform on neonates within the first few days of birth as hemipenes become increasingly difficult to evert as neonates age, however, with practice they are easily identified without full eversion. SECTION TWO The thermal biology of E. tympanum in the field is restricted by both the thermal properties of their habitat (Chapter 3) and behavioural modifications when faced with a predation threat (Chapter 4). The available temperatures in the field suggest that TSD is biologically relevant in the species and not just a laboratory artefact; E. tympanum can attain mean selected temperatures achieved in the laboratory but the proportion of time at the temperature is restricted. Females actively thermoregulate in the field, although they are restricted in their efficiency of thermoregulation by environmental constraints, for example, microhabitat structure, weather conditions, predator avoidance and social ranking. The highly territorial nature and high densities of E. tympanum present in Kanangra Boyd National Park potentially force less dominant individuals into less favourable habitats that are significantly cooler. An important point is that gravid females in more favourable habitats in the period encompassing the middle third of development (the assumed sex determining period) are selecting higher temperatures, with lower variance and have greater thermoregulatory efficiency than during the rest of pregnancy, therefore, thermoregulating more precisely during this thermosensitive period (Chapter 3). Chemosensory cues provide important information on the risk of predation. Hence, chemoreception is a common mechanism used by many species to detect the presence of, and subsequently respond to, a potential predator. The perceived risk of predation may force retreat to sub-optimal conditions, forcing a trade-off between the risk of predation and the ability to acquire resources. The basking regime maintained by gravid female E. tympanum, can directly alter sex ratios of offspring produced through temperature-dependent sex determination (Chapter 1). The avoidance of predator scents may restrict basking ability and in turn alter the sex of offspring produced. I measured responsiveness to chemical cues using tongue flicks as an indicator of chemical discrimination in females of different reproductive condition. I then measured activity and basking behaviour of gravid and non-gravid females in experimental enclosures in the presence of various chemical stimuli to determine if basking opportunity is compromised by the presence of a predator scent. Females respond differently depending upon reproductive condition, with gravid females responding most significantly to a predator scent. Activity, basking frequency, and time spent in the open (basking duration) are significantly reduced in gravid females in the presence of a predator stimulus. Under laboratory conditions, gravid females modify their behaviour and forego the opportunity to bask when there is a perceived predation risk (Chapter 4). SECTION THREE As female viviparous reptiles can regulate the temperature of the embryo by maternal temperature selection (Chapter 1), the occurrence of TSD in E. tympanum opens the possibility for females to select the sex of offspring. Reproducing females may benefit by facultatively adjusting their investment into sons over daughters or vice versa, in response to population wide shifts in adult sex ratios. Female E. tympanum, can manipulate the sex of their offspring in response to sex imbalances in the population using temperature-dependent sex determination (Chapter 5). When adult males are scarce, females produce male-biased litters and when adult males are common, females produce female-biased litters. The cues used by a female to assess the adult population are not known, but presumably depends upon the female's experience throughout the breeding season and is the subject of further investigation (Chapter 6). The maternal manipulation of offspring sex ratio in E. tympanum suggests a selective advantage of temperature-dependent sex determination. Any facultative sex ratio response needs to recognise the scarcity of one sex in order to overproduce that sex in the next generation; offspring sex ratio will vary inversely with adult sex ratio. Maternal sex allocation in E. tympanum is linked with population (or adult) sex ratio (Chapter 5), and one of the mechanisms by which females recognise an imbalance may be linked to visual recognition of males (Chapter 6). Females maintained throughout pregnancy without any male stimulus produce entirely male offspring (Chapter 5). In contrast females exposed to male stimulus produce both sexes (Chapter 5). Females respond differently to varying degrees of male stimulus and visual recognition of males in a population may be more important than chemoreception. In the absence of visual cues, females produce more male offspring, even when chemosensory cues are present (Chapter 6). The study system presented here offers many advantages over oviparous species with TSD, due to E. tympanum being relatively short lived and fast maturing. Thus, the fitness consequences over multiple generations as a result of gestation can be investigated. Viviparity allows maternal control of embryonic temperature during gestation and a means of maternal sex allocation. Until now the maternal side of TSD and sex allocation has been where the mother deposits her eggs and the allocation of sex steroid hormones at oviposition, both of which have been difficult to study. The work presented and the study system itself should inspire great interest in TSD and viviparous reptiles.
4
Robert, Kylie Anne. "Temperature-dependent sex determination in the viviparous lizard Eulamprus tympanum." University of Sydney. Biological Science, 2003. http://hdl.handle.net/2123/557.
Full textAbstract:
Abstract There are a remarkable variety of sex determination systems among different animal taxa. In most animals, sex is determined chromosomally. Although in an increasing number of animals sex determination has been found to be influenced primarily by the environment. Species with genotypic sex determination (GSD) have their sex determined at the time of fertilization, by genetic factors alone and those with environmental sex determination (ESD) have their sex determined by environmental factors that act after fertilization. Temperature-dependent Sex Determination (TSD), whereby the sex of the developing embryos depends on the temperature at which they develop is widespread in oviparous reptiles and occurs in all crocodilians, marine turtles and tuatara examined to date and is common in many freshwater turtles and lizards. SECTION ONE Temperature-dependent sex determination (TSD) was never expected to occur in viviparous reptiles, as thermoregulation by pregnant females would result in relatively stable gestation temperatures. Temperature-dependent sex determination and viviparity goes against all the basic assumptions that TSD occurs in oviparous reptiles where temperatures within a nest vary widely. However, skewed sex ratios as a result of incubation temperature indicated the possibility of TSD in the viviparous lizard Eulamprus tympanum. In my first experiments I show the first recorded case of a viviparous reptile with TSD. The developing embryos of the viviparous skink E. tympanum are subject to TSD, with gestation temperature having a highly significant effect on sex and warmer temperatures giving rise to male offspring (Chapter 1). Sex is fully determined at the time of birth and can be differentiated histologically into testes or ovaries (Chapter 2). The morphology and histological characteristics of the gonads of neonatal E. tympanum resulting from the treatment temperatures described in chapter 1 illustrate that sex in E. tympanum is easily distinguished at the time of birth and corresponds with the presence or absence of hemipenes. Males are histologically characterised by an elongated gonad consisting of seminiferous tubules with either no cortical epithelium or, if present at all, in a very thin band. If they are present, M�llerian ducts, showing signs of degeneration, are attached to the kidney by a shortened mesosalpinx. Females are histologically characterised by an irregularly shaped gonad consisting of a thick cortical epithelium that occasionally contains oocytes. The M�llerian ducts are obvious structures attached to the kidney by a fibrous mesosalpinx. The presence or absence of hemipenes is a reliable technique for determining sex in newborn E. tympanum. Sex determination is easiest to perform on neonates within the first few days of birth as hemipenes become increasingly difficult to evert as neonates age, however, with practice they are easily identified without full eversion. SECTION TWO The thermal biology of E. tympanum in the field is restricted by both the thermal properties of their habitat (Chapter 3) and behavioural modifications when faced with a predation threat (Chapter 4). The available temperatures in the field suggest that TSD is biologically relevant in the species and not just a laboratory artefact; E. tympanum can attain mean selected temperatures achieved in the laboratory but the proportion of time at the temperature is restricted. Females actively thermoregulate in the field, although they are restricted in their efficiency of thermoregulation by environmental constraints, for example, microhabitat structure, weather conditions, predator avoidance and social ranking. The highly territorial nature and high densities of E. tympanum present in Kanangra Boyd National Park potentially force less dominant individuals into less favourable habitats that are significantly cooler. An important point is that gravid females in more favourable habitats in the period encompassing the middle third of development (the assumed sex determining period) are selecting higher temperatures, with lower variance and have greater thermoregulatory efficiency than during the rest of pregnancy, therefore, thermoregulating more precisely during this thermosensitive period (Chapter 3). Chemosensory cues provide important information on the risk of predation. Hence, chemoreception is a common mechanism used by many species to detect the presence of, and subsequently respond to, a potential predator. The perceived risk of predation may force retreat to sub-optimal conditions, forcing a trade-off between the risk of predation and the ability to acquire resources. The basking regime maintained by gravid female E. tympanum, can directly alter sex ratios of offspring produced through temperature-dependent sex determination (Chapter 1). The avoidance of predator scents may restrict basking ability and in turn alter the sex of offspring produced. I measured responsiveness to chemical cues using tongue flicks as an indicator of chemical discrimination in females of different reproductive condition. I then measured activity and basking behaviour of gravid and non-gravid females in experimental enclosures in the presence of various chemical stimuli to determine if basking opportunity is compromised by the presence of a predator scent. Females respond differently depending upon reproductive condition, with gravid females responding most significantly to a predator scent. Activity, basking frequency, and time spent in the open (basking duration) are significantly reduced in gravid females in the presence of a predator stimulus. Under laboratory conditions, gravid females modify their behaviour and forego the opportunity to bask when there is a perceived predation risk (Chapter 4). SECTION THREE As female viviparous reptiles can regulate the temperature of the embryo by maternal temperature selection (Chapter 1), the occurrence of TSD in E. tympanum opens the possibility for females to select the sex of offspring. Reproducing females may benefit by facultatively adjusting their investment into sons over daughters or vice versa, in response to population wide shifts in adult sex ratios. Female E. tympanum, can manipulate the sex of their offspring in response to sex imbalances in the population using temperature-dependent sex determination (Chapter 5). When adult males are scarce, females produce male-biased litters and when adult males are common, females produce female-biased litters. The cues used by a female to assess the adult population are not known, but presumably depends upon the female�s experience throughout the breeding season and is the subject of further investigation (Chapter 6). The maternal manipulation of offspring sex ratio in E. tympanum suggests a selective advantage of temperature-dependent sex determination. Any facultative sex ratio response needs to recognise the scarcity of one sex in order to overproduce that sex in the next generation; offspring sex ratio will vary inversely with adult sex ratio. Maternal sex allocation in E. tympanum is linked with population (or adult) sex ratio (Chapter 5), and one of the mechanisms by which females recognise an imbalance may be linked to visual recognition of males (Chapter 6). Females maintained throughout pregnancy without any male stimulus produce entirely male offspring (Chapter 5). In contrast females exposed to male stimulus produce both sexes (Chapter 5). Females respond differently to varying degrees of male stimulus and visual recognition of males in a population may be more important than chemoreception. In the absence of visual cues, females produce more male offspring, even when chemosensory cues are present (Chapter 6). The study system presented here offers many advantages over oviparous species with TSD, due to E. tympanum being relatively short lived and fast maturing. Thus, the fitness consequences over multiple generations as a result of gestation can be investigated. Viviparity allows maternal control of embryonic temperature during gestation and a means of maternal sex allocation. Until now the maternal side of TSD and sex allocation has been where the mother deposits her eggs and the allocation of sex steroid hormones at oviposition, both of which have been difficult to study. The work presented and the study system itself should inspire great interest in TSD and viviparous reptiles.
5
Baker, Melia. "Skeletal Development in Oviparous and Viviparous Populations of Saiphos equalis." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/honors/129.
Full text
6
Macias, Garcia Constantino de Jesus. "Sexual behaviour and trade-offs in the viviparous fish Girardinichthys multiradiatus." Thesis, University of East Anglia, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279739.
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7
Härkönen, L. (Laura). "Seasonal variation in the life histories of a viviparous ectoparasite, the deer ked." Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789514298967.
Full textAbstract:
Abstract The life histories of ectoparasites are shaped by both host and off-host environment. A suitable host is primarily needed during reproduction, whereas juvenile stages outside the host are directly exposed to environmental variability. Viviparity, i.e. the development of an embryo inside the body of the mother resulting in large offspring size, increases offspring survival. The production of large offspring has its consequences in terms of high variation in offspring age and in the environment that each young individual will face. I used a viviparous ectoparasite, the deer ked (Lipoptena cervi), to investigate the consequences of long reproductive lifespan and varying offspring environment on offspring life-histories and seasonal adaptations. Offspring life-histories varied seasonally. I showed that the resources provided by the deer ked females determine offspring performance throughout its off-host period. Offspring size increased towards the spring and the end of the reproductive period, and simultaneously offspring survival and cold tolerance increased. Seasonal variation in offspring size did not reflect the resources that would guarantee offspring survival during the longest diapause or the highest cold tolerance during the harshest winter period. Diapause intensity varies with birth time according to the expected length of the winter ahead. However, the deer ked pupae, regardless of their age, overwinter at an opportunistic diapause, which may be terminated rapidly only by an exposure to high temperature. Contrary to general observations, photoperiod has no role in regulating the seasonal shifts of the deer ked. Neither is high cold tolerance associated only with diapause, but it remains high through four seasons, also in the active developmental and adult stages. I also evaluated the effects of life-history variation on the invasion potential of the deer ked. I conducted a large-scale transplant experiment to test the survival and pupal development at and beyond the current range. I found that the lower spring and summer temperatures and the shorter growth season in the north cause a deterioration in pupal performance and shorten the flight period. However, the colder climate may not totally prevent further spread. A more important factor that will affect deer ked invasion is host availability, and especially in Finland, the density of the moose population. Seasonal variation in offspring life histories in viviparous ectoparasites differs from the variation patterns reported in most invertebrates. This may be due to the extremely large offspring size and to the fact that maternally derived resources determine offspring performance through the entire off-host period. Variation in offspring performance is thus determined by maternal resources and seasonal variation in the condition of the mooseTiivistelmä Useimpien ulkoloisten elinkierto on riippuvainen isännästä ja isännän ulkopuolella kasvavien jälkeläisten kohtaamista ympäristöoloista. Viviparia eli jälkeläisen kehitys naaraan sisällä ja siitä usein seuraava suuri jälkeläiskoko parantavat jälkeläisten selviytymistä. Suurten jälkeläisten tuottaminen pitkällä aikavälillä johtaa siihen, että eri-ikäiset jälkeläiset kohtaavat vuodenajasta riippuen hyvin erilaiset olosuhteet. Väitöstyössäni tarkastelin Suomessa nopeasti yleistyneen hirvieläinten ulkoloisen, hirvikärpäsen (Lipoptena cervi), avulla, mitä seurauksia viviparialla, pitkällä lisääntymiskaudella ja ympäristön vuodenaikaisvaihtelulla on jälkeläisten elinkierto-ominaisuuksiin. Väitöskirjatyössäni havaitsin, että hirvikärpäsjälkeläisten elinkiertopiirteet vaihtelevat jälkeläisen syntymäajan mukaan. Osoitin myös, että hirvikärpäsnaaraan jälkeläisilleen tarjoamat ravintovarat määrittelevät jälkeläisten isännästä riippumattoman elinkierron aikaisen menestyksen. Jälkeläisten keskimääräinen koko kasvoi lisääntymiskauden edetessä talvesta kohti kevättä, jolloin myös selviytyminen ja kylmänsietokyky paranivat. Jälkeläiskoon vuodenaikaisvaihtelu ei näin ollen vastaa jälkeläisten tarvitsemia resursseja suhteessa talvehtimisen pituuteen eikä korreloi koville talvipakkasille altistumisen todennäköisyyden kanssa. Lepotilan keston määrittelevä diapaussin syvyys vaihteli syntymävuodenaikaa vastaavasti. Diapaussin havaitsin kuitenkin olevan ensisijaisesti opportunistinen, jolloin pelkästään korkea lämpötila voi nopeasti päättää lepotilan kaikenikäisillä yksilöillä. Vastoin yleisiä käsityksiä valorytmi ei vaikuta diapaussin säätelyyn. Vastoin ennakko-odotuksia kylmänsietokyky säilyy korkeana vuoden ympäri ja kaikissa tutkituissa elinkierron vaiheissa. Sovelsin tutkimieni elinkiertopiirteiden vaikutusta myös lajin invaasiokykyyn, ja tutkin istutuskokeen avulla koteloiden selviytymistä ja kehitystä nykyisellä esiintymisalueella ja sen pohjoispuolella. Alhaisemmat kevät- ja kesälämpötilat sekä lyhyempi kasvukausi vähentävät aikuiseksi selviytymistä ja lyhentävät lentoaikaa syksyllä. Ilmastotekijöiden suhteen hirvikärpänen voisi esiintyä nykyistä pohjoisempana. Tärkein tekijä hirvikärpäsen leviämistä tarkasteltaessa on kuitenkin sopivien isäntäeläimien saatavuus ja Suomen oloissa erityisesti hirven eli hirvikärpäsen pääisännän kannan tiheys. Tutkimukseni perusteella ulkoloisten vivipariasta seuraava jälkeläisten elinkiertopiirteiden ajallinen vaihtelu eroaa muiden selkärangattomien vastaavasta vaihtelusta. Yhtenä syynä eroihin lienee se, että hirvikärpäsnaaras tuottaa erityisen suuria jälkeläisiä ja että jälkeläiset puolestaan ovat täysin riippuvaisia emon antamista resursseista. Emon lisääntymisresurssit ja hirven kunnon vuodenaikaisvaihtelu vaikuttavat mahdollisesti siihen, minkälaisia jälkeläisiä hirvikärpänen milloinkin kykenee tuottamaan
8
Tedder, Amanda, Rebecca Pyles, and James R. Stewart. "Impact of viviparity on skeletal development in a reproductively bimodal squamate species." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/53.
Full textAbstract:
Among vertebrates, oviparous animals lay eggs with a calcified eggshell and eggs are laid in an external environment, while viviparous animals retain eggs in oviduct until they give birth to live young. Viviparity has evolved in the lineage of snakes and lizards (squamates) over 100 times, more than all other vertebrate groups. Embryos of oviparous squamates obtain calcium from both yolk and eggshell while their viviparous counterparts lack a calcified eggshell and must obtain their calcium solely from yolk, or from yolk plus placental transfer. During embryonic development, squamates rely on calcium to build the skeleton before hatching. The extent of skeletal ossification at hatching or birth varies considerably among vertebrates. This study aims to determine if skeletal development/ossification varies in association with reduced eggshell calcium in embryos of viviparous squamate species. We studied the amount of ossification and overall size of embryos and hatchlings from an oviparous and a viviparous population of the reproductively bimodal lizard Zootoca vivipara. Previous studies suggested that limb development is delayed, and that overall size is reduced in viviparous squamates. We tested the hypothesis that viviparous embryos and hatchlings are more skeletally immature and smaller in size than oviparous embryos and hatchlings in squamates. To achieve this, specimens from both populations, spanning multiple stages of embryonic development including hatchlings, were cleared & stained to reveal skeletal cartilage and bone. Lengths of total body, humerus, femur, skull and Meckel’s cartilage were measured from photographs of cleared & stained specimens taken with a Cannon EOS 70D camera on a Motic, Leica MZ9 Compound Microscope, with a measurement reference in each picture. Photos were calibrated to the measurement reference and total length measurements were obtained using iSolutionLite® software. In addition to total measurements, the lengths of ossified portions on the humerus and femur were also measured. Preliminary results revealed that total length of the skull and body are reduced in embryos and hatchlings of viviparous specimens. Total length of the limbs and of Meckel’s cartilage are not significantly different between populations. However, it appears that the amount of ossification in the limbs is reduced in oviparous specimens. These preliminary findings do not support our hypothesis and indicate that reduction in eggshell calcium in embryos of viviparous populations does not negatively impact ossification during development but does influence overall size.
9
Fregoso, Santiago. "Pattern and Mechanism of Calcium Mobilization During Embryonic Development in a Viviparous Snake, Virginia striatula." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etd/1712.
Full textAbstract:
Yolk supplies the majority of embryonic calcium in snakes. Oviparous and viviparous snakes also receive calcium late in development from the eggshell and placenta, respectively. The pattern and mechanism of calcium transport are partly understood for oviparous snakes. I studied a viviparous snake, Virginia striatula, to determine the pattern of embryonic calcium accumulation as well as the ontogenetic expression of calcium transporting proteins in extraembryonic tissues. The pattern of embryonic calcium uptake of V. striatula occurs late in development, during the phase of highest embryonic growth. Calbindin-D28k, Ca2+ ATPase, and carbonic anhydrase II are expressed in chorioallantoic membrane, while yolk sac only expresses calbindin-D28k, coincident with the timing of calcium transport in embryos of V. striatula. Thus, the pattern of embryonic calcium accumulation in V. striatula is similar to that of oviparous snakes. Although calbindin-D28k and Ca2+ ATPase are likely active in embryonic calcium transport, the role of carbonic anhydrase II remains less clear.
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Spindle, S. Tyler. "Confocal Microscopy Study of the Embryonic Development of the Viviparous Nemertean Prosorhochmus americanus Reveals Larval Features Supporting Indirect Development In Hoplonemerteans." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3186.
Full textAbstract:
Recent studies of hoplonenemertean planuliform larvae have clarified their development and provided insight into larval evolution within the phylum. However, an assessment of viviparous development using modern techniques is lacking. To help facilitate a comprehensive comparative evaluation of developmental diversity within hoplonemerteans, we have conducted a confocal laser scanning microscopy investigation of the development in Prosorhochmus americanus, one of the few viviparous hoplonemertean species. Phalloidin staining provides evidence of a modified transitory larval epidermis, and reveals that the foregut, midgut, proboscis, central nervous system, and body wall musculature form early in development, consistent with observations for planktonic and encapsulated hoplonemertean larvae. However, invaginations characteristic of these larvae were not observed. Acetylated tubulin labeling and light microscopy shows that embryos are uniformly ciliated, and some specimens possess a caudal ciliary cirrus and/or apical tuft which are characteristic of planktonic larvae. These are interpreted as vestigial structures in the non-swimming P. americanus embryos. The findings provide additional evidence that hoplonemerteans exhibit a form of metamorphosis in their life history and thus exhibit indirect development. However, a comparative assessment of larval features in P. americanus suggests an evolutionary trend towards direct development in this species.
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Seo, Joonbae. "Molecular genetics studies of bZIP transcription factor, TRAB1, and MYB transcription factor, ME97, on the Viviparous 1 promoter in Zea mays." [Ames, Iowa : Iowa State University], 2008.
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MALGIOGLIO, ANTONINO. "THE MAIZE VP*404 MUTANT IS IMPAIRED IN MOCO-S BIOSYNTHESIS." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/168723.
Full textAbstract:
part 1: DESICCATION TOLERANCE
In maize, desiccation tolerance is acquired by the embryo at a precise developmental stage, between 20 and 25 DAP (days after pollination) and is probably related to the maturation process characterized by the accumulation of storage products and LEA (late embryogenesis abundant) proteins, that have a protective role. In viviparous (vp) mutants, that are deficient in ABA synthesis or lack an active vp1 factor, embryos do not express the normal set of maturation phase proteins; it is also conceivable that these embryos do not acquire the desiccation tolerance. To verify this, we applied premature desiccation to developing vp embryos about 25 DAP, and compared their germination capacity to embryos not subjected to such treatment.
When cultured immediately after their excision, immature embryos of all mutants tested germinated with a high frequency (95-100%) similarly to their wild type counterparts. if they were cultured following a premature dehydration treatment, only vp1 and vp10 maintained a partial desiccation tolerance while the other mutants lost it. These results seem to suggest that acquisition of desiccation tolerance requires the completion of the steps between carotenoid production and the later stages of ABA biosynthesis, with a possible protective role of carotenoid against oxidative phenomena that take place even during desiccation, because the metabolism is still active.
part 2: THE MAIZE vp*404 MUTANT is IMPAIRED in Moco BIOSYNTHESIS
In maize the vp10 and vp15 genes have been isolated; they encode the orthologs of the Arabidopsis Cnx1, and Cnx7 respectively, which catalyse the last steps of Moco-O biosynthesis. Moco-O is required for the activity of both Nitrate Reductase and Sulfite Oxidase.
Maize mutants defective in Moco-S are instead unknown, but Moco-S
mutant plants have been described for Arabidopsis (ABA3), tomato (flacca) and tobacco (ABA1), which lack AO and XDH activities, but show normal NR enzymatic activity. These mutants show a wilty phenotype and are impaired in stress responses.
vp*404 is a viviparous mutant with light green seedlings, reduced content of chlorophyll, carotenoids and ABA.Complementation tests with all viviparous mutants with green seedlings reported in literature showed that vp*404 defines a new vp gene.
Moco enzyme activities analysis showed normal value for SO and an extremely reduced activity for both AO and XDH, suggesting that vp*404 is likely a Moco-Sulfurase defective mutant. In Arabidopsis the ABA3 gene encodes the Moco-Sulfurase.
Blast analysis performed with the ABA3 sequence , gave two sequences with high Identity on chromosome 6. The two sequences, which are 30kb distal, encode the Moco-S N-terminal and the Moco-S C terminal domain respectively. However,since in all Eukaryotes analysed the two protein domains are encoded by the same gene, we refer to the gene in Sorghum as a model, and we have reconstructed in silico the structure of a maize unique theoretical gene, in which the C terminal domain was correctly oriented and 30,000bp between the two domains were arranged.
Specific primers were designed on the basis of the theoretical gene and the corresponding cDNA sequence was analysed by means of a RT-PCR approach. Preliminary data seem to confirm the proposed gene model, however gene isolation and sequence analysis will be necessary to confirm our hypothesis.
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Josserand, Rémy. "Dégradation de l'habitat et réponse au stress : de la physiologie a la biologie de la conservation." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066711/document.
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L'anthropisation croissante et les changements globaux entrainent de nombreuses perturbations dans l'environnement conduisant à la dégradation, et même à la destruction d'habitat. Le modèle allostatique proposé par McEwen et Wingfield en 2003 permet de mieux appréhender les relations entre physiologie et réponses démographique dans le cadre de la physiologie de la conservation. A travers des approches expérimentales en milieux controlé et semi-naturel nous avons testé l'effet de d'un stress chronique sur les changements des traits d'histoires de vie et les paramétres physiologique chez le lézard vivipare (Zootoca vivipara). Nous discutons de la caractérisation de la charge allostatique et des effets à court terme et long terme d'un stress chronique et l'utilisation de la charge allostatique comme indicateur de la dégradation de l'habitat. Ce travail pourra être utilisé afin de mieux comprendre et prédire la dynamique des populations naturelles soumises aux changements globauxIncreasing anthropogenic and global changes are causing many disturbances in the environment leading to degradation and even destruction of habitat. The allostatic model proposed by McEwen and Wingfield in 2003 provides a better understanding of the relationships between physiology and demographic responses within the framework of conservation physiology. Experimental approaches in controlled and semi-natural environments have tested the effect of chronic stress on changes in life histories and physiological parameters in the viviparous lizard (Zootoca vivipara). We discuss the characterization of allostatic charge and the short-term and long-term effects of chronic stress and the use of allostatic charge as an indicator of habitat degradation. This work can be used to better understand and predict the dynamics of natural populations subjected to global changes
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Leão, Michelle Furquim. "Morfologia do fígado e das brânquias do guaru (Poecilia vivipara) expostos às concentrações agudas do herbicida Roundup original (glifosato(N-(fosfonometil) glicina))." Universidade Federal de Goiás, 2007. http://repositorio.bc.ufg.br/tede/handle/tede/5225.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The sharp toxicity of the herbicide original Roundup (Glifosato), one of the more acquaintances and maybe one of the more used dessecantes in direct planting in the farmings in the area Centro Oeste and in every country now, it was investigated through the effects detected in the fish Poecilia viviparous...
A toxicidade aguda do herbicida Roundup original (Glifosato), um dos mais conhecidos e talvez um dos mais utilizados dessecantes em plantio direto nas lavouras na região Centro Oeste e em todo país atualmente, foi investigada através dos efeitos detectados no peixe Poecilia vivípara...
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TAMBOURGI, Mirna Regina dos Santos. "Biologia reprodutiva do tubarão galha-branca oceânico, Carcharhinus longimanus, no Atlântico Sudoeste e Equatorial." Universidade Federal Rural de Pernambuco, 2010. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6425.
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In the period from December 2003 to December 2009, the reproductive tract were collected from 201 individuals of Carcharhinus longimanus, caught by of commercial tuna boats in the fleet, who were pelagic longline fisheries and hand line in the area located between latitudes 06 º 45'N and 23 ° 36'S and longitudes 018 ° 44'W and 053 º 13'W. Among the 201 individuals captured, 98 were females (74.5 – 227 cm TL) and 103 were males (72 – 242 cm TL) with a sexual proportion males to females of 1:1. Females were categorized as immature (N = 78; 74.5 – 170 cm TL), matures (N = 13; 165 – 223 cm TL), pré-ovulatory (N = 2; 181 – 187 cm CT) and pregnant (N = 5; 169 – 227 cm TL). The uterine fecundity ranged from 1 to 10 embryos. The cycle of pregnancy is annual with birth occurring at the end / beginning of the year. The size at first maturity of females was estimated at 170 cm TL. Of the 103 males captured, 75 were immature (72 to 160 cm TL), 8 maturing (170 - 196) and 20 were mature (160 - 242 cm TL). The size of sexual maturity was between 160 and 170 cm.
No período de dezembro de 2003 a dezembro de 2009, foram coletados os aparelhos reprodutores de 201 espécimes de Carcharhinus longimanus, capturados por meio de barcos da frota comercial atuneira, que realizaram pescarias com espinhel pelágico e linha de mão, na área localizada entre as latitudes 06º45’N e 23º36’S e as longitudes de 018º44’W e 053º13’W. Deste total, 98 eram fêmeas (74,5 a 170 cm CT), maduras (N= 13; 165 a 223 cm CT), pré-ovulatórias (N= 2; 181 e 187 cm CT) e prenhes (N= 5; 169 a 227 cm CT). A fecundidade ovariana variou de 1 a 10 folículos vitelogênicos e a uterina, de 1 a 10 embriões. O ciclo de gestação é anual com nascimento ocorrendo ao final/início do ano. O tamanho de primeira maturação das fêmeas desta espécie é de 170 cm CT. Dos 103 machos capturados, 75 eram imaturos (72 – 160 cm CT), 8 em maturação (170 - 196) e 20 eram maduros (160 – 242 cm CT). O tamanho de primeira maturação sexual entre 160 e 170 cm.
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Bates, Kimberly M. "The biology of dictyocaulus viviparus in Missouri /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841262.
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McKeand, Jacqueline B. "Aspects of the immumobiology of Dictyocaulus viviparus infection." Thesis, University of Glasgow, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314727.
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Rozen-Rechels, David. "Patrons et optimisation des comportements de thermo-hydrorégulation dans un paysage hétérogène Water restriction in viviparous lizards causes transgenerational effects on behavioral anxiety and immediate effects on exploration behavior When water interacts with temperature: Ecological and evolutionary implications of thermo‐hydroregulation in terrestrial ectotherms." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS345.
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Les changements climatiques actuels induisent des modifications du paysage thermique et hydrique dans lequel vivent les organismes. Il est attendu que les organismes ectothermes, qui régulent leur température corporelle via le comportement, aient la capacité de tamponner tout ou partie des effets négatifs de ces modifications sur la physiologie et les performances. Toutefois peu d’études se sont penchées sur les coûts que peuvent avoir les modifications de l’environnement hydrique sur les comportements de thermorégulation. L’objectif principal de cette thèse est de décrire des mécanismes comportementaux de régulation conjointe de la température corporelle et de la balance hydrique, définis alors comme comportements de thermo-hydrorégulation. Je me suis concentré sur l’étude du comportement d’un squamate de milieu tempéré, le lézard vivipare (Zootoca vivipara) à l'aide de protocoles expérimentaux et de suivis en milieu naturel. Mes résultats permettent de mettre en évidence des compromis et des synergies entre les patrons de comportements d’hydrorégulation et de thermorégulation selon les conditions environnementales. Ces ajustements comportementaux s'expliquent par une nécessité de limiter les pertes en eaux. Une diminution de la disponibilité hydrique dans l’environnement ainsi que la déshydratation de l’animal induisent aussi des modifications dans les stratégies de thermorégulation. Ces travaux suggèrent qu’une prise en compte conjointe des contraintes thermiques et hydriques dans l’environnement semble critique à l’étude des réponses des organismes aux changements globaux, et pourrait questionner notre compréhension des réponses individuelles à ces changementsActual climate changes drive modifications of the thermal and water landscapes where live organisms. Thermoregulation in ectotherm species mostly rely on behavioral adjustments. These adjustments buffer the negative effects of these environmental changes on the physiology and the performances of the individuals. However, too few studies focused on the costs of changes in the water environment on thermoregulation behaviors. The main objective of this thesis is to highlight behavioral patterns involved in the joint regulation of body temperature and water balance, hereafter called thermo-hydroregulation behaviors, which would be critical to understand the responses of organisms to global changes. I focused on studying space use behaviors (activity patterns, micro-habitat selection) of a temperate squamate species, the common lizard (Zootoca vivipara) through experimental set-ups in laboratory or outdoor conditions, as well as a comparative study of natural populations in the Massif Central, France. My results highlighted that behavioral regulation of the water balance can trade-off or act in synergy with thermoregulation behaviors according to environmental conditions. The observed behavioral adjustments could consist in a water conservation strategy. A decrease in water availability in the environment as well as a dehydration induced changes in thermoregulation strategies (body temperature, thermoregulation accuracy). These studies highlighted the importance of a joint consideration of the thermal and water constraints when studying the ectotherms responses to global change, and questioned our current understanding of individual and populational responses to these changes
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Hagberg, Malin. "Immune cell responses to the cattle lungworm, Dictyocaulus viviparus /." Uppsala : Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/200837.pdf.
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Bugler, Melanie Jane. "An investigation into use of the freshwater gastropod Viviparus as a recorder of past climatic change." Thesis, University of Plymouth, 2011. http://hdl.handle.net/10026.1/2573.
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Through isotopic analysis of Viviparus lentus (V. lentus) a high resolution record of stepwise changes in δ18O and δ13C across the Eocene / Oligocene transition and Oi-1 glacial maximum has been produced for the continental Solent Group strata, Isle of Wight (UK). Comparison of this V. lentus δ18Ocarb. record with high resolution marine δ18Ocarb. records shows that similar isotopic shifts exist in the near coastal continental and marine realms. In order to calculate palaeotemperatures from this new continental record an investigation into the biology of modern Viviparus and its effect on the isotopic composition of its shell carbonate was undertaken. Experimental measurements of the 18O/16O isotope fractionation between the biogenic aragonite of Viviparus and its host freshwater were undertaken on samples derived from the Somerset Levels in order to generate a genus specific thermometry equation. The results from using this new Viviparus equation on fossil V. lentus shell fragments suggests that aquatic and terrestrial biota were being affected by climate change associated with the Late Eocene Event. This conicides with a decrease in mammal species richness in the Osborne Member, reaching its climax at the end of the Osborne / Seagrove Bay Members. This event is followed by a brief warming in the Bembridge Limestone which was marked by a within-Europe mammal turnover involving dispersal from the south and an increase in species richness, concurrent with this is an increase in size of Harrisichara gyrogonites. An additional investigation into seasonal isotopic variability using whole well preserved V. lentus specimens has also revealed a shift from tropical /subtropical to temperate climatic zones occurring before the Eocene /Oligocene boundary and Oi-1 glacial maximum. Overall the evidence provided by these investigations would suggest that climatic change was already in progress prior to the build up of glacial ice on Antarctica.
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Strube, Christina [Verfasser]. "Charakterisierung der Vakzinekandidaten Major Sperm Protein und Paramyosin von Dictyocaulus viviparus / Christina Strube." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2010. http://d-nb.info/1009653520/34.
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Benstead, Rachael Samantha. "The effects of the natural vertebrate steroid 17β-oestradiol and the xeno-biotic vertebrate oestrogen receptor agonist bisphenol-A on reproduction in selected temperate freshwater gastropods : the potential for (neuro-) endocrine disruption." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4664.
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Evidence of feminising effects, including additional or enlarged female organs, have been reported in the (sub)-tropical freshwater prosobranch Marisa cornuarietis exposed to vertebrate estrogen receptor agonists. The primary symptom is an increase in the number of eggs laid, but this is only observed when exposure occurs at relatively low temperatures. This research project exposed temperate freshwater prosobranchs and a pulmonate to 17β-oestradiol (10-200 ngL-l, nominal) in an outdoor mesocosm subject to natural seasons to determine whether similar effects occur in European native temperate freshwater gastropods. Laboratory exposures to 17β-oestradiol (1-100 ngL-l, nominal) and Bisphenol-A (0.2-20 ngL-l, nominal) were also carried out over a range of different temperatures and photoperiods to simulate natural seasons. In the mesocosm exposures, significant increases in reproduction were measured in Viviparus viviparus, Bithynia tentaculata and, if the mortality rate was not significantly increased, Planorbarius corneus. It was observed that increases only occurred after the onset of autumn. In the laboratory, the oviposition rate in P. corneus was constant at 20oC with a 16h photoperiod, but declined significantly at 15oC with a 12h photoperiod, except at 100 ngL-l 17β-oestradiol, when the rate remained constant. There were no similar effects from Bisphenol-A exposure. Small increases in reproduction were observed in all the prosobranch exposures to both compounds, but the interpretation of the data was confounded by several factors (test chemical degradation, high mortality rates and parasitized organisms) and there were no significant differences. In conclusion, there were indications that all of the assessed species were capable of increased reproduction, and in P. corneus this appears to be a perpetuation of summer oviposition rates in autumnal conditions. The consequences of this effect in annual semelparous pulmonates may not be detrimental at the population level, but the long-term fitness of iteroparous prosobranchs that practice ‘restrained reproduction’ in early breeding seasons may be adversely affected.
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Su, Lixun. "The role of the Viviparous1 (Vp1) gene in anaerobic inhibition of maize embryo germination." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464392.
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Schunn, Anne-Marie [Verfasser]. "Seroepidemiologische Untersuchung zur Verbreitung von Dictyocaulus viviparus in Milchviehherden in Deutschland / Anne-Marie Schunn." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2012. http://d-nb.info/1030352305/34.
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Scott, Carolyn Anne. "The role of T cells in the immune response to Dictyocaulus viviparus in calves." Thesis, University of Glasgow, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321072.
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Joekel, Deborah Elisabeth [Verfasser]. "Rekombinante Antigene als Vakzinekandidaten gegen den Rinderlungenwurm Dictyocaulus viviparus – in vitro Untersuchungen und Immunisierungsversuche / Deborah Elisabeth Joekel." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2015. http://d-nb.info/1073881318/34.
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Gånheim, Charina. "Studies on the acute phase reaction during respiratory infections in calves /." Uppsala : Dept. of Clinical Sciences, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/v180.pdf.
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Pilorge, Thierry. "Dynamique comparée de populations de lézards vivipares : régulation et variabilité intra- et interpopulationnelle." Paris 6, 1988. http://www.theses.fr/1988PA066481.
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L'objectif de ce travail est de mettre en évidence les mécanismes régulateurs de populations de lézards vivipares du mont Lozère. Il met l'accent sur la grande variabilité démographique entre populations et entre années et sur le rôle prépondérant joue par la taille corporelle dans cette variabilité. Il souligne, en outre, l'importance primordiale de la densité dans la régulation de ces populations et met en évidence les relations de compétition asymétrique entre les différentes catégories démographiques considérées (males et femelles adultes, subadultes). Enfin, il propose les moyens a mettre en œuvre pour élucider les points restant obscurs
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LECOMTE, POPINEAU JANE. "Role du comportement dans l'organisation et la regulation des populations de lezards vivipares." Paris 11, 1993. http://www.theses.fr/1993PA112382.
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Ce travail vise a elucider comment la densite modifie les comportements des individus et comment ces comportements agissent en retour sur la dynamique de la population. Pour mieux cerner le role des comportements dans la regulation des populations de lezards vivipares, nous avons mene des experimentations en enclos semi-naturel ciblees sur des individus d'age, de sexe, de morphologie et d'histoire de vie connus. Nous avons defini les modalites comportementales individuelles et interactives puis mis en evidence la variabilite des modalites comportementales au sein des classes d'age et de sexe. Nous avons ensuite evalue les relations comportementales entre classes par le biais de confrontations, observe comment la densite influencait les comportements des differentes classes et experimente si la densite, comme indice du contexte social, poussait les individus a disperser. D'une maniere generale, les caracteristiques des individus, leur appartenance a un niveau de densite dans leur population d'origine et/ou leur statut de dispersant sont lies a des traits comportementaux particuliers. Les principaux resultats ont montre que: 1) certains traits de comportement paraissent avec un determinisme ontogenique chez cette espece; 2) il existe une competition intraspecifique entre individus de classes differentes; 3) le niveau de densite n'a pas la meme influence sur les comportements individuels selon l'age et le sexe; les comportements des males adultes sont les plus influences par la densite; 4) la densite d'origine affecte les interactions entre individus de maniere differente selon l'age et le sexe; 5) le pattern d'activite differe entre subadultes dispersants et philopatriques; 6) la dispersion juvenile parait conditionnee par le niveau de densite en femelles adultes. Tous ces resultats mettent en avant l'importance du contexte social dans l'evolution des populations. Le role du comportement et des interactions sociales est alors discute dans le cadre des connaissances sur la regulation des populations de lezards vivipares
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Pilorge, Thierry. "Dynamique comparée de populations de lézards vivipares régulation et variabilité intra-et interpopulationnelle /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37617551j.
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Osman, Abdel Malik Mohamed. "Studies on the effect of low level albendazole therapy in calves on 'Dictyocaulus viviparus' (Railliet and Henry 1907)." Thesis, Royal Veterinary College (University of London), 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517990.
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Cezaro, Marcela Cristina de. "Nematódeos gastrintestinais e pulmonares e parâmetros bioquímicos séricos em bezerros naturalmente infectados." Botucatu, 2016. http://hdl.handle.net/11449/143764.
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Orientador: Elizabeth Moreira dos Santos SchmidtResumo: Este trabalho encontra-se dividido em três capítulos. O capítulo 1 versa sobre uma revisão de literatura que teve como objetivo a realização de um levantamento retrospectivo sobre os endoparasitas em bovinos no Brasil, que também incluiu dados mundiais. No capítulo 2, objetivou-se investigar os nematódeos gastrintestinais (GI) e pulmonares que parasitam bovinos jovens. Para isso, foram utilizados 140 bezerros mestiços, de dois a 12 meses de idade, clinicamente saudáveis, de duas propriedades leiteiras nos municípios de Botucatu e Manduri, estado de São Paulo. Durante um ano, trimestralmente, amostras de fezes foram coletadas diretamente da ampola retal para a realização da contagem de OPG pela técnica de McMaster modificada e pesquisa de L1 de Dictyocaulus viviparus pela modificação da técnica de Baermann. Além disso, coproculturas foram realizadas em pool de amostras para a observação das larvas infectantes. Na propriedade de Manduri, houve um aumento significativo da contagem de OPG no inverno. Na propriedade de Botucatu, os animais com até três meses de idade apresentaram maiores contagens de OPG quando comparados aos animais mais velhos. Em geral, foram observados ovos de estrongilídeos, Strongyloides spp., Moniezia spp., Trichuris spp. e oocistos de Eimeria spp. Nas coproculturas, em ordem de prevalência, foram recuperadas larvas infectantes de Cooperia spp., Haemonchus spp., Oesophagostomum spp. e Trichostrongylus spp. As L1 de D. viviparus foram recuperadas somente na ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This work was divided into three chapters. The chapter 1 aimed to perform a review article based on a retrospective survey of epidemiological studies examining endoparasites that affect bovine in different regions of Brazil, which also included international data. The chapter 2 aimed to determine the gastrointestinal (GI) and pulmonary parasites that affect calves. For this, we used 140 clinically healthy crossbred calves, two to 12 months old, which belonged to two private farms in the municipalities of Botucatu and Manduri, São Paulo state. The animals were monitored for 12 months. Feces were collected directly from the rectum every three months. Fecal egg counts were determined using the modified McMaster technique with a sensitivity of 50 eggs per gram of feces (EPG). Coproculture was performed on pooled samples to identify Strongylida infective larvae. First-stage larvae of Dictyocaulus viviparus were identified by a modified Baermann method. The calves from Manduri farm showed a significant increase in the fecal egg counts in the winter when to compare to other seasons. The Botucatu farm calves differed significantly in the age groups in that younger calves (2 – 3 months old) showed a higher EPG than older calves (8 – 12 months old). Generally, we found Strongyle type-eggs, Strongyloides spp., Moniezia spp., and Trichuris spp. eggs and Eimeria spp. oocysts. The most prevalent genera in all coprocultures were: Cooperia spp., Haemonchus spp., Oesophagostomum spp., and Tri... (Complete abstract click electronic access below)
Mestre
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Costa, Gilzônia Veloso da. "Aclimatização de Epidendrum viviparum Lindl (ORCHIDACEAE) em substratos provenientes de subprodutos de palmáceas nativas." Universidade Federal de Roraima, 2014. http://www.bdtd.ufrr.br/tde_busca/arquivo.php?codArquivo=280.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA aclimatização é uma fase importante no desenvolvimento de mudas, e pode representar um fator limitante no processo de micropropagação. A escolha do substrato correto é importante para propiciar às mudas boas condições de desenvolvimento, e também podem influenciar na taxa de sobrevivência das mesmas. Esta pesquisa estudou a utilização de subprodutos de palmáceas regionais na aclimatização da orquídea Epidendrum viviparum. Essa espécie possui ocorrência no estado de Roraima e sua forma de vida é epífita. As plântulas foram inicialmente semeadas in vitro no Laboratório de Substâncias Bioativas do Programa de Pós-graduação em Recursos Naturais da Universidade Federal de Roraima e após 24 meses foram cultivadas na casa de vegetação do Núcleo de Recursos Naturais da Universidade Federal de Roraima, no município de Boa Vista, Roraima. O delineamento utilizado foi o inteiramente casualizado, com cinco tratamentos e vinte e cinco repetições, num total de 125 plântulas. Os tratamentos foram compostos por: T1 - fibra de coco; T2 - caroços de tucumã (Astrocaryum vulgare Mart), T3 - caroços de patauá (Oenocarpus bataua Mart.), T4 - caroços de açaí (Euterpe oleracea Mart.) e T5 - caroços de buriti (Mauritia flexuosa L.). Os dados foram submetidos à análise de variância e ao teste de Tukey a 5% de probabilidade. Os parâmetros biométricos avaliados aos 180 dias do cultivo ex vitro foram: altura da parte aérea, comprimento da maior raiz, número de raízes, número de folhas, massa fresca e o percentual de sobrevivência. Em relação aos substratos, foram analisados: matéria seca, teor de umidade, material mineral, matéria orgânica, fósforo dissolvido, nitrogênio e pH. O substrato composto por caroços de açaí proporcionou o maior comprimento da parte aérea e o maior peso fresco das plântulas. O substrato com caroços de tucumã induziu o maior número de folhas e de raízes, sendo os mais indicados no cultivo dessa orquidácea. Já o substrato constituído por caroços de buriti provocou o menor desenvolvimento das plântulas de E. viviparum, em relação aos outros substratos estudados.
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Maluf, Mirian Perez. "Estudo de um mutante de caratenoide e viviparo causado por transposon em zea mays." [s.n.], 1991. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317401.
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Orientador : William Jose da SilvaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-07-14T00:28:12Z (GMT). No. of bitstreams: 1 Maluf_MirianPerez_M.pdf: 3876462 bytes, checksum: 3b86e7a3fca8f97c106a5093910c2fff (MD5) Previous issue date: 1991
Mestrado
Genetica
Mestre em Ciências Biológicas
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Rascle, Pauline. "Biologie et écologie d'une population isolée : exemple d'Eryngium viviparum et perspectives pour sa conservation en France." Thesis, Brest, 2018. http://www.theses.fr/2018BRES0075/document.
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L'isolement géographique est une menace élevée pour le maintien des populations sur le long terme. Il est donc primordial de comprendre selon quel degré la viabilité des populations est affectée par leur isolement, notamment en vue de définir des priorités en terme de conservation. Eryngium viviparum J.Gay (Apiaceae) est une des espèces végétales les plus menacées d'Europe avec une distribution ibéro-armoricaine très fragmentée. En France, son statut de conservation est devenu particulièrement critique avec la disparition de la presque totalité de ses populations au cours des années 1980, à l'exception d'une seule, suite à la destruction de son habitat par les activités humaines. Cette unique population fait depuis plusieurs années l'objet d'une conservation et d'une gestion attentives au sein d'une réserve protégée. Malgré ces actions, l'isolement de cette population soulève des interrogations quant à sa viabilité sur le long terme. Dans ce cadre, et à travers une approche multidisciplinaire, la thèse propose un renforcement des connaissances sur les caractéristiques écologiques et biologiques d'E. viviparum, et plus particulièrement concernant sa dernière population française. Elle s'articule selon trois axes principaux : (1) L'étude de l'amplitude écologique de l'espèce, puis la caractérisation de ses préférences écologiques à fine échelle au sein de la dernière population française (2) L'évaluation de la viabilité de la population isolée d'après ses paramètres démographiques, son niveau de diversité génétique et son degré de différenciation avec d'autres populations. (3) L'expérimentation des modalités de réintroduction en France. Les résultats apportés par ce travail contribueront à définir les prochaines priorités en matière de gestion et de conservation pour assurer le maintien d'E. viviparum sur le long terme en France. Le cas d' E. viviparum fournit un bon modèle d'étude pour évaluer l'effet de l'isolement sur la dynamique d'une population isolée et pour appliquer une conservation adaptée à cette problématiqueThe geographical isolation is an important threat for the long term preservation of populations. It is crucial to understand how the viability of populations is affected in such context, in particular to define conservation priorities. Eryngium viviparum J.Gay (Apiaceae) is one of the most endangered plant in Europe, with a fragmented distribution between the NW of the Iberian peninsula and Brittany. ln France, the species is maintained only on a single locality, after the destruction of its habitat by human activities during 1980s. Despite a conservation program and an attentive management within a protected area, the strong isolation experimented by this population bring up questions about its long-term viability. In this context, through a multidisciplinary approach, this thesis aims to improve the biological and ecological knowledge of E. viviparum, and more particularly within its last French population. This thesis is organized according three main axes : (1) The study of large-scale E. viviparum ecological amplitude, and the characterization of its fine scale ecological preferences within the last french population. (2) The viability evaluation of the isolated population according to its demographic modalities, and to its genetic structure in comparison with Iberian populations. (3) The experiment of its reintroduction modalities in France.The results of this study will contribute to define the long-term conservation priorities of E. viviparum in France. Finally, the case of E. viviparum is a good model to study the effect of the isolation on an isolated population dynamic, and to apply adapted conservation for species in a similar context
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Lorioux, Sophie. "INFLUENCES ENVIRONNEMENTALES PRECOCES ET REGULATION MATERNELLE DU DEVELOPPEMENT : IMPLICATIONS ECOLOGIQUES ET EVOLUTIVES CHEZ DEUX ESPECES DE SQUAMATES." Phd thesis, Université de Poitiers, 2011. http://tel.archives-ouvertes.fr/tel-00691167.
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Les organismes sont soumis aux fluctuations de l'environnement et les stades précoces (vie embryonnaire) sont particulièrement sensibles aux perturbations qui peuvent modifier les trajectoires développementales. La sensibilité thermique des embryons est une caractéristique générale chez les vertébrés et aurait constitué une force sélective majeure dans l'évolution des soins parentaux (hypothèse de Farmer, 2000). Par ailleurs, le développement embryonnaire est un processus complexe et les influences environnementales peuvent avoir des effets très différents selon la période d'exposition. Pourtant cette variabilité est insuffisamment prise en compte en écologie évolutive et dans l'étude des soins parentaux. L'environnement maternel peut constituer une interface entre l'environnement extérieur et les embryons. La régulation des conditions thermique du développement est très répandue chez les vertébrés. Si les ectothermes produisent une chaleur métabolique négligeable, ils ont développé une diversité de stratégies comportementales et physiologiques pour protéger les embryons des variations thermiques. Les soins parentaux prénataux sont associés à un changement du comportement maternel avec une augmentation des activités de thermorégulation, ainsi qu'à de profondes modifications énergétiques et physiologiques. Nous avons examiné l'importance de la régulation maternelle des conditions prénatales chez deux espèces de serpents aux modes de reproduction contrastés, une ovipare (python de Children, A childreni) et une vivipare (la vipère aspic, V aspis). L'originalité de ce travail repose sur la prise en compte du caractère dynamique de la sensibilité embryonnaire et des contraintes maternelles. Nos résultats nous ont permis de démontrer l'existence d'une sensibilité thermique stade-dépendent, avec une plus forte sensibilité aux perturbations en début de développement, et l'importance de l'accès à la température préférée pendant cette étape. En parallèle, nous avons pu mettre en évidence un investissement maternel important (thermorégulation comportementale), et les contraintes associées (augmentation des prises de risque, pertes hydriques, coûts énergétiques). Ces données obtenues soutiennent la théorie de Farmer et l'importance de la prise en charge maternelle des stades précoces. Cette sensibilité thermique pourrait avoir constitué une force sélective majeure dans la complexification des soins parentaux (transition vers la viviparité, soins aux œufs).
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Lazari, Ovadia. "Secreted and neuromuscular acetylcholinesterase genes in Dictyocaulus viviparus and the role of the a7 nicotinic acetylcholine receptor subunit in the host response to the parasite." Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490375.
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May, Katharina [Verfasser]. "Genetische Analysen zur Endoparasitenresistenz und Einfluss von Infektionen mit Magen-Darm-Strongyliden, Fasciola hepatica und Dictyocaulus viviparus auf Milchproduktions- und Fruchtbarkeitsparameter bei Milchkühen / Katharina May." Hannover : Stiftung Tierärztliche Hochschule Hannover, 2019. http://d-nb.info/118965475X/34.
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Tessier, Louis. "Étude in vitro de la performance du gastéropode de faible longévité Viviparus georgianus (Lea) à titre de bioindicateur de la pollution par le cadmium et le mercure." Thèse, Université du Québec à Trois-Rivières, 1993. http://depot-e.uqtr.ca/5157/1/000603609.pdf.
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Laabs, Eva-Maria Wiebke [Verfasser]. "Transcriptome analysis of preadult hypobiotic and non-hypobiotic L5 stages as well as in vitro studies on the sexual maturation of preadult larvae of the bovine lungworm Dictyocaulus viviparus / Eva-Maria Wiebke Laabs." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2011. http://d-nb.info/1018968520/34.
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Karanikola, Sofia Nikolaou [Verfasser]. "Entwicklung einer innovativen diagnostischen Technik unter Verwendung der xMAP®Luminex®Technologie für die simultane Detektierung von Antikörper gegen Cooperia oncophora, Dictyocaulus viviparus und Fasciola hepatica in bovinen Serum und Milchproben / Sofia Nikolaou Karanikola." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1114735191/34.
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Atkins, N. "Parental effects in two species of viviparous lizards: Niveoscincus microlepidotus and N. ocellatus." Thesis, 2007. https://eprints.utas.edu.au/8098/1/01FrontAtkins.pdf.
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This thesis focuses on maternal contributions to offspring fitness in viviparous lizards. Although parental effects may include both pre- and postpartum components, the majority of squamate reptile species exhibit no parental care: parental effects on offspring fitness can, therefore, be imposed only until the time of oviposition or parturition.
In viviparous reptiles, offspring are retained in utero for the entire duration of embryogenesis, but in most species the majority of embryonic nutrition is supplied through the yolk with a small contribution by a simple placenta. In some reptilian species, viviparity has evolved further, resulting in a diverse range of placental arrangements and a complete spectrum of embryonic nutritional modes being displayed across a wide range of taxa. It has been suggested that facultative placentotrophy (the ability to supplement an adequate yolk supply) allows the introduction of flexibility into the timing of parturition by providing embryos with additional energy stores to utilise if parturition is delayed. My study species were two closely related viviparous lizards found in Tasmania, Australia. Previously, embryonic nutrition has been shown to be predominantly placentotrophic in Niveoscincus ocellatus; I have now determined that embryonic nutrition is predominantly lecithotrophic in N. microlepidotus, and that females may utilise facultative placentotrophy only in some years.
My thesis investigated the major hypothesis that deferral of parturition after completion of embryonic development is a key strategy employed by females of viviparous lizards to maximise offspring fitness. The three interlinked papers on this theme that I have included in my thesis support my hypothesis. In N. ocellatus, deferring parturition in response to cold conditions had no effect on offspring phenotype at birth, dispersal distance or survivorship of offspring after release; however, there was a significant negative effect on offspring growth measured after release, which has profound implications for age and size at maturity. I found that females from a high elevation population were less able to defer birth under “long” periods (three weeks) of cold conditions than females of a low elevation population. I attribute the reduced ability of females from the high elevation population to defer parturition to selection for preventing births too close to winter.
However, in the biennially reproducing N. microlepidotus, my results have identified that the naturally protracted deferral of parturition from autumn until spring represents a trade-off between offspring quality and offspring size. Finer scale variation in the timing of parturition also influences neonatal characteristics: I have shown that there is an effect of date of birth on several key offspring characteristics at birth in N. microlepidotus. Experimental manipulations of the maternal environment demonstrated that females are able to defer birth for an additional four weeks at the end of gestation, but with no significant effect on offspring characteristics.
How is the timing of parturition determined if fully developed embryos may be held in utero for significant periods of time? I discovered that in N. microlepidotus the uteri are equally responsive to hormonal stimulation (arginine vasotocin (AVT) and prostaglandin (PGF2a) in autumn and spring. In both N. microlepidotus and N. ocellatus, females are more responsive to AVT than to PGF2a, and the response to AVT is decreased, but not prevented, by B-adrenergic stimulation. In N. ocellatus, temperature modulates the response to AVT in vivo, with the time to parturition increasing as temperature decreases. In these viviparous species, then, the endocrine cascade leading to parturition is modulated by the B-adrenergic system.
The final component of the thesis investigated male reproductive success in a population of N. ocellatus. I determined the paternity of 65% of the offspring: the results demonstrate that the species has a high level (93%) of multiple paternity within litters, with females having access to many males. While female size is correlated with litter size, I was unable to identify any factors that determine male reproductive success. In addition, the size of the father within a litter had no effect on offspring characteristics at birth, and no measured parental characteristics were determinants of offspring survival.
This thesis has demonstrated that females of viviparous lizards exhibit a suite of characteristics that enable them to manipulate offspring characteristics through the control of the timing of parturition. This provides new evidence to support Shine’s “Maternal Manipulation Hypothesis”.
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Dinis, Marco André Ferreira. "Gene flow and environmental differentiation between viviparous and ovoviviparous populations of Salamandra algira tingitana." Master's thesis, 2016. https://repositorio-aberto.up.pt/handle/10216/90944.
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Parsley, LM. "Routes and mechanisms of embryonic hormone exposure and endocrine disruption in a viviparous lizard." Thesis, 2013. https://eprints.utas.edu.au/22582/1/Pasley_Whole_%20thesis.pdf.
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The mechanisms of embryonic exposure to hormones in viviparous reptiles are speculative, despite detailed understanding of exposure in oviparous species and eutherian mammals. The yolk of oviparous species and the placenta of eutherian mammals are key sources of steroid to developing embryos. Importantly, most viviparous reptiles utilise a yolk and a placenta to support embryogenesis. Maternally-derived testosterone and oestradiol have major impacts on development. The yolk and the placenta are therefore both potential sources of testosterone and oestradiol to embryonic viviparous lizards, but this remains to be tested.
Many endocrine disrupting chemicals (EDCs) impair gonadal development by affecting testosterone and oestradiol concentrations. Some EDCs disrupt the activity of aromatase which catalyses the conversion of testosterone to oestradiol. Embryonic development can be affected either by alterations in maternal hormone concentrations or by direct exposure to EDCs. Embryonic viviparous reptiles are at particular risk due to the multiple routes of potential exposure. However, no study has examined the routes of embryonic exposure to EDCs or examined EDC effects in viviparous reptiles. The major aims of this study on the viviparous lizard, Niveoscincus metallicus, were to confirm that the yolk is a source of testosterone and oestradiol to developing embryos; to demonstrate the placenta and embryonic tissues as sites of aromatase; and to examine the effects of gestational exposure to two EDCs (diethylstilbestrol and the herbicide atrazine) on gonadal development.
Yolks of N. metallicus were sampled from vitellogenesis through to the final stages of gestation. As in in oviparous reptiles, the yolk of N. metallicus contains testosterone and oestradiol, however, the stages at which the steroids decline are not comparable to oviparous species, as the placenta also provides steroid. Aromatase activity was measured in the placenta and embryonic tissues during three progressive stages of development. Placental aromatase activity was highest in the early stages of development, suggesting oestrogen synthesis in N. metallicus supersedes yolk reserves. The effects of oestrogenic EDCs on gonadal development were characterised by dosing gestating females with diethlystilbestrol at 100 or 10 μg/kg and examining the gonads of neonates. The effects of gestational exposure to a single dose of atrazine at 10 μg/kg on gonadal development were also characterised by examining the gonads of neonates. Diethlyslstilbestrol and atrazine disrupt gonadal development: by comparing the developmental effects observed from exposure to diethylstilbestrol and atrazine in males and females, I conclude that atrazine disrupts gonadal development in N. metallicus via increased aromatase activity. This thesis has expanded our understanding of the endocrine environment in which embryos of viviparous lizards develop, and has provided new evidence of the potential impacts of EDCs on viviparous vertebrates.
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Dinis, Marco André Ferreira. "Gene flow and environmental differentiation between viviparous and ovoviviparous populations of Salamandra algira tingitana." Dissertação, 2016. https://repositorio-aberto.up.pt/handle/10216/90944.
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Cunningham, GD. "Degrees of change : varying patterns of plasticity across warming climatic landscapes in a viviparous lizard." Thesis, 2018. https://eprints.utas.edu.au/30035/1/Cunningham_whole_thesis.pdf.
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As climates warm, populations of species will be faced with novel climatic environments, to which they may not be adapted. Due to local adaptation and biogeographic and demographic history, populations are likely to differ in their response to changed conditions in the short-term, and their capacity to evolve in response to changed conditions in the long-term. However, predictions of the effects of climate change often assume that short-term responses will be homogeneous both among populations, and among the individuals within them. Such assessments also often ignore the capacity for these responses to evolve in response to novel selective pressures, assuming that the relationship between environmental temperature and phenotype will be stable, both geographically and temporally. Because reptiles are ectotherms, environmental temperatures determine many aspects of their physiology, behaviour and ecology. As such, reptiles are thought to be at especially high risk from changing climates. Understanding the short-term effects of temperature, how patterns of responses have evolved, and the capacity of populations to adapt into the future has, therefore, never been more important in the light of ongoing climate change.
In this thesis I use the spotted snow skink, Niveoscincus ocellatus, as a model organism to investigate climatic drivers of intraspecific patterns of thermal developmental plasticity. Previous research has demonstrated that climatically distinct populations of N. ocellatus differ in a host of phenotypic characteristics, including morphology, physiology, behaviour and, intriguingly, sex determination system. I use a range of techniques incorporating a long-term field study, experiments, and simulation modelling to explore the short- and long-term effects of changing climates, focussing on two key traits: phenology and offspring sex.
I demonstrate that thermal reaction norms of phenology are consistent among populations, but that populations differ in the degree of variation at the phenotypic level between the individuals within them. I show that birth date has significant consequences for growth during the first year of life, but does not affect survival. These findings have important consequences for population persistence. As climates warm, birth dates will advance across the range of the N. ocellatus and may have positive affects on population persistence.
I also demonstrate intraspecific variation in sex determination systems among populations in N. ocellatus. I show that environmental temperatures do not affect offspring sex in a highland population. In a lowland population, however, I show that environmental temperature affects offspring sex, and that this effect is not altered by other variables. Using an individual-based evolutionary simulation model, parameterised with data from a long-term study of two populations, I then extend an explanatory conceptual framework, which explains the evolution of sex determination systems as arising from sex-specific benefits of date of birth, so that it applies across the range of the species’ present-day climatic landscape. Finally I use this model to predict how patterns of selection for sex determination systems and sex ratios will be altered throughout the species’ range.
My thesis has contributed significantly to our understanding of the climatic and ecological factors that have shaped patterns of variation among and within populations and how species, and the populations within them, will respond to changing climates.
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Chung, Chen-yo, and 鍾成侑. "Exploration of non-canonical expression of developmental genes in the asexual viviparous pea aphid using fluorescence approaches." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/39194265777581632775.
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博士國立臺灣大學
昆蟲學研究所
102
The pea aphid Acyrthosiphon pisum is a genomic model insect and a unique model for polyphenism due to its developmental plasticity in response to environmental cues. To uncover the relation of embryonic development and gene regulations, reliable expression protocols and functional tools are required. Whole-mount in situ hybridization (WISH) we previously reported can be used to monitor gene expressions during embryogenesis, however chromogenic signals are defective in double detection of genes and construction of three-dimensional image. I therefore developed a fluorescent in situ hybridization (FISH) protocol to overcome these defects. By means of different advantages of four FISH methods, I successfully detected gene expressions in somatic and extraembryonic tissues. The combination of FISH methods also allowed the double detection of genes in somatic cells, germ cells, or both in one preparation. This FISH protocol further aids me in revealing the expression of developmental genes. In our previous findings, mRNA expression of A. pisum hunchback (Aphb), a Drosophila homolog of hunchback, was found in the segments and central nervous system of mid/late stages apart from the anterior pole of early stages, implicating its conserved roles among arthropods and lower organisms. Here I discovered a novel expression pattern of Aphb in germ cells of the pea aphid. Germline expression of Aphb initiates while primordial germ cells formed, and maintains throughout developmental stages. In late embryos, Aphb is also expressed in maturing germaria as well as the protruding oocytes. These findings implicate that the homolog of hb in aphids replaces the role of bicoid in anterior determination and, moreover, has the roles in formation of germ cells. To reveal whether the complex of Nanos (Nos) and Pumilio (Pum) is required to repress the translation of anterior-localized Aphb in the posterior, I analyzed the structure of A. pisum Pum (ApPum) protein and the expression patterns of Appum mRNA. The highly conserved protein structure indicates the ApPum can repress the translation of Aphb, though the asymmetric expression of Appum mRNA, like Drosophila pum, was not found. Together with the known expression patterns of Aphb, Appum, and A. pisum Nos (ApNos), it appears that posterior determination of the pea aphid relies on the ApNos/ApPum complex and the anterior is determined by Aphb.
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Hsiao, Yi-min, and 蕭逸旻. "Axis formation and endosymbiotic regulation of germline development in the parthenogenetic and viviparous pea aphid Acyrthosiphon pisum." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2ugn33.
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博士國立臺灣大學
生物科技研究所
106
Introduction. Aphids are hemipteran sap-sucking insects that can vector plant viruses. They propagate rapidly via parthenogenetic (asexual) and viviparous reproduction from generation to generation yet they enrich genetic diversity, once every life cycle, through sexual oviparous reproduction. In both asexual and sexual morphs, the primary endosymbiotic bacteria (endosymbionts) are critical to the synthesis of essential amino acids. With such special reproductive and endosymbiotic features described above, the pea aphid Acyrthosiphon pisum became a rising model insect after its whole genome sequence was published in 2010. Here in my study, I aimed to study two developmental events during early embryogenesis of the parthenogenetic and viviparous pea aphid: (1) the formation of anteroposterior (AP) and dorsoventral (DV) axes; and (2) the regulation of germline development by endosymbiosis. Results (I) AP Axis Formation. Transcripts of Aphb, an ortholog of the Drosophila hunchback in the pea aphid, are known to be localized to the anterior poles of the oocytes and syncytia. This implies that anterior localization of Aphb mRNA may specify the anterior axis in the asexual viviparous pea aphid. In order to understand whether ApHb protein also participates in anterior formation via asymmetric localization as Aphb mRNA, dissected ovarioles were stained using an affinity-purified antibody against ApHb. I found that ApHb, unlike anteriorly-localized Aphb, was uniformly distributed in oocytes and syncytia. This suggests that ApHb is not involved in anterior formation. Both Aphb and ApHb, like their insect orthologs, were identified in the embryonic neuroblasts, indicating that the Aphb gene remained a conserved role in neurogenesis. Nevertheless, expression of Aphb and ApHb was unexpectedly detected in the germ cells throughout all developmental stages. Such germline expression pattern of hb has not been reported in other insect models, suggesting that Aphb may obtain a new role in germline development in asexual aphids. Transcripts of Apcad, an ortholog of the conserved posterior gene cad in the pea aphid, were not identified in the posterior region until blastoderm formation. The absence of posterior localization of Apcad mRNA in oocytes and syncytia suggests that Apcad, though remains conserved in posterior development, is not involved in posterior determination. Results (II) DV Axis Formation. For studying how the DV axis was established, I detected expressions of orthologous mRNAs known to participate in the establishment of the DV axis in Drosophila, assuming that asymmetric localization of the target mRNAs was also conserved in the specification of DV axis in the asexual pea aphid. Transcripts of the four decapentaplegic paralogs (Apdpp1–4), however, unlike dorsal expression of dpp mRNA in Drosophila, was not particularly restricted to any regions within the egg chambers. I did not make antibodies against ApDpp1–4 proteins to detect their distributions. Nonetheless, signals of the phosphorylated Mothers Against Dpp (pMad) protein—a conserved indicator of Dpp activity—and those of Apzen (aphid zerknüllt (zen) ortholog) mRNA—a conserved marker for the insect extraembryonic membrane that forms from the dorsal region—were asymmetrically localized to one side within the egg chambers. Coincidentally, localization of Apsog mRNA, an orthologous mRNA of the ventral gene short gastrulation (sog) in Drosophila, was identified at the opposite side of pMad and zen expressions. The asymmetric localization of pMad/zen and Apsog was not detected until cellularization of the blastoderm, suggesting that formation of the DV axis stars from blastulation or it occurs earlier in the syncytia but does not rely on these conserved DV determinants. Results (III) germline development and endosymbiosis. The primary endosymbiont Buchnera aphidicola invades into the egg chamber prior to gastrulation and ever since then it is associated with the embryonic germ cells throughout embryogenesis. Based upon the fact that the B. aphidicola and germ cells are closely associated, we aimed to understand whether B. aphidicola was essential to the development of germ cells. In the aposymbiotic pea aphids, where B. aphidicola was eliminated by antibiotics, the number of germ cells was largely reduced before katatrepsis (embryo flip), suggesting that B. aphidicola provides nutrients required for the proliferation of germ cells. Expression of Caspase-3 was identified in the germ cells of the aposymbiotic morphs, further suggesting that the reduction of germ cells is caused by apoptosis. The migratory path of germ cells, nevertheless, remained almost the same as that in aphids without the treatment of antibiotics. This implies that the delivery of the guiding signals for germline migration toward the gonads is independent from endosymbiosis. Conclusion. In this study, the aphid orthologs of the developmental toolkit genes for the axis formation and body patterning, including Aphb, Apcad, ApDl, Aphh, Apcact, Apdpp1–4, Apsog, mad, and Apzen, were analyzed that allows to reveal how asexual viviparous aphid established body plan. After the formation of axes, Buchnera cells invade into the embryos that were required for regulating host germ-cell survival. Taken together, these results may shed light on how parthenogenetically viviparous insects established their body axes and how obligate symbionts of insects may play a non-nutritional role for host embryogenesis and organogenesis.
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張紘嘉. "The Transcription Factor OsVP1 (Viviparous-1) Plays a Pivotal Role in Repression of α-Amylase Gene Expression in Rice." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/56365500939031772068.
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碩士國立嘉義大學
生物農業科技學系碩士班
101
Among cereal grains, only rice has peculiar characteristic of promoting coleoptiles elongation when grains are germinate under flooding with lack of oxygen. α-Amylase is produced in the germinating rice seeds submerged in water, whereas it is not in the flooding-intolerant cereals. The production ofα-amylase in rice grains control in energy provision may play a pivotal role in the tolerance to flooding during germination and coleoptiles elongation. Our previous results show that in order to save the energy, GA induction of α-amylase activity has significantly declined in the hypoxic aleurone layers surrounding the starchy endosperms. However, the underlying molecular mechanism for this effect has been elusive so far. Previous studies have demonstrated that VP1 inhibits induction of α-amylase genes in endosperm of developing cereal grains and thereby appears to be involved in preventing precocious germination. It suggests that hypoxia-inducible OsVP1 might be involved in hypoxia-dependent repression of α-amylase genes expression in endosperm of rice seeds. In the present study, we identified an OsVP1 activation tagged rice mutant line, and was designated as AcOsVP1, which confers late-heading and a low rate of viviparous germination phenotypes as compared with wild type. We found that AcOsVP1 leads to enhance sugar suppression ofα-amylase genes expression in rice embryos, but cannot affect GA-responsive α-amylase genes expression in germinated endosperms. We also found that under hypoxia, no significant different was observed between wild type and AcOsVP1 for sugar starvation induction of α-amylase genes in embryos, whereas AcOsVP1 significantly causes inhibition of GA-inducible α-amylase genes expression in hypoxic endosperms. Transient expression assay indicates that the αAmy3 activity is inhibited by OsVP1 but enhanced by OsVP1-RNAi under hypoxia. Taken together, our results suggest that OsVP1 may be involved in sugar-dependent repression in embryos, hypoxia-dependent repression in endosperms of α-amylase gene expression in rice.
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Kleinteich, Thomas [Verfasser]. "The evolution of intrauterine feeding in the Gymnophiona (Lissamphibia) : a comparative study on the morphology, function, and development of cranial muscles in oviparous and viviparous species / vorgelegt von Thomas Kleinteich." 2009. http://d-nb.info/997711833/34.
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