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Márcia Maria Gentile Bitondi - One of the best experts on this subject based on the ideXlab platform.
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Ovariole structure and stages characterization.
2016Co-Authors: Juliana Ramos Martins, Márcia Maria Gentile BitondiAbstract:The ovariole comprises the anterior terminal filament, germarium and developing follicles (vitellarium) as indicated at the right. The oocytes are marked in yellow. The Ovarioles are categorized according to the degree of development in stages S0, S1, S2, S3 and S4. Stage S0: presence of initial oocytes (cystocytes) and precursors of nurse and somatic cells in the germarium. Stage S1: an oocyte accompanied by differentiated nurse cells is positioned at the basal region of the ovariole. Stage S2: a slight constriction between the basal oocyte and accompanying nurse cells marks the beginning of oocyte chamber and nurse cell chamber separation; the basal oocyte is surrounded by follicle cells. Stage S3: a sequence of developing oocytes and nurse cell chambers is evident in the ovariole; the larger oocyte at the basal region is well-separated from the nurse cell chamber. Stage S4: presence of several developing oocytes and nurse cell chambers through the ovariole; a quasi-fully or a fully developed oocyte is evident at the most basal region. The classification of the maturing oocytes in stages 1 to 7 (stage 6 is not shown) was based in Wilson et al. [44].
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Immunolocalization of HEX 110 in RNase A-treated Ovarioles (stage S2) of queenright nurse workers.
2016Co-Authors: Juliana Ramos Martins, Márcia Maria Gentile BitondiAbstract:(A) Control ovariole non-incubated with RNase A. HEX 110 green foci (labeled with anti-HEX 110/Alexa-Fluor 488) are abundant in the nucleus (arrowheads) and cytoplasm (arrows) of nurse (Nc) and follicle (Fc) cells surrounding the oocyte (stage 2, see Fig 2). (B) Ovariole incubated with RNase A shows scarce HEX 110 foci (arrows). DAPI-staining (blue) in B highlights the small nuclei of follicle cells (Fc) that surround the oocyte (stage 1, see Fig 2) and are interspersed between the large nurse cell (Nc) nuclei. Quantification of pixels intensity in the selected areas (dashed rectangles) of the images obtained from RNase A-treated and untreated Ovarioles showed lower intensity in RNase A-treated (Mean: 17.29; Min/Max gray values: 0/255; IntDen: 575.51) than in untreated controls (Mean: 29.39; Min/Max: 0/255; IntDen: 978.45).
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Immunolocalization of HEX 110 in Ovarioles (stage S1) of nurse workers from a queenright colony.
2016Co-Authors: Juliana Ramos Martins, Márcia Maria Gentile BitondiAbstract:HEX 110 foci (green) were detected with anti-HEX 110/Alexa-Fluor 488. Propidium iodide (red) stains DNA and RNA and was used to highlight the nuclei. (A) Upper region of the germarium of two Ovarioles (separated by dashed lines) showing germ- and somatic cell precursors containing cytoplasmic (arrows) and nuclear (arrowheads) HEX 110 foci. (B) Lower region of the germarium showing initial oocytes (cystocytes) (Oc) and nurse- and follicle cell precursors, these still morphologically undistinguishable from each other. (C) The same germarium region showing cytoplasmic (arrows) and nuclear (arrowheads) HEX 110 foci. (D) A follicle at the basal region of the ovariole showing a developing oocyte (Oc, stage 1, see Fig 2), and nurse cells (Nc). Oocyte nucleus (N) and cytoplasm (c) are indicated. Small follicle cells (Fc) are seen around the oocyte and nurse cell chamber. (E) The same follicle shown in D. Arrows point to cytoplasmic HEX 110 foci. The arrowhead points to nuclear HEX 110 foci in a follicle cell within the nurse cell chamber.
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A Honey Bee Hexamerin, HEX 70a, Is Likely to Play an Intranuclear Role in Developing and Mature Ovarioles
2013Co-Authors: Juliana R. Martins, Lucas Anhezini, Zila Lp SimÕes, Rodrigo Pires Dallacqua, Márcia Maria Gentile BitondiAbstract:Insect hexamerins have long been known as storage proteins that are massively synthesized by the larval fat body and secreted into hemolymph. Following the larval-to-pupal molt, hexamerins are sequestered by the fat body via receptormediated endocytosis, broken up, and used as amino acid resources for metamorphosis. In the honey bee, the transcript and protein subunit of a hexamerin, HEX 70a, were also detected in ovaries and testes. Aiming to identify the subcellular localization of HEX 70a in the female and male gonads, we used a specific antibody in whole mount preparations of ovaries and testes for analysis by confocal laser-scanning microscopy. Intranuclear HEX 70a foci were evidenced in germ and somatic cells of Ovarioles and testioles of pharate-adult workers and drones, suggesting a regulatory or structural role. Following injection of the thymidine analog EdU we observed co-labeling with HEX 70a in ovariole cell nuclei, inferring possible HEX 70a involvement in cell proliferation. Further support to this hypothesis came from an injection of anti-HEX 70a into newly ecdysed queen pupae where it had a negative effect on ovariole thickening. HEX 70a foci were also detected in Ovarioles of egg laying queens, particularly in the nuclei of the highly polyploid nurse cells and in proliferating follicle cells. Additional roles for this storage protein are indicated by the detection of nuclear HEX 70a foci in post-meiotic spermatids and spermatozoa. Taken together, these results imply undescribed roles for HEX 70a in the developing gonad
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A Honey Bee Hexamerin, HEX 70a, Is Likely to Play an Intranuclear Role in Developing and Mature Ovarioles and Testioles
PloS one, 2011Co-Authors: Juliana Martins, Zilá Luz Paulino Simões, Lucas Anhezini, Rodrigo Pires Dallacqua, Márcia Maria Gentile BitondiAbstract:Insect hexamerins have long been known as storage proteins that are massively synthesized by the larval fat body and secreted into hemolymph. Following the larval-to-pupal molt, hexamerins are sequestered by the fat body via receptor-mediated endocytosis, broken up, and used as amino acid resources for metamorphosis. In the honey bee, the transcript and protein subunit of a hexamerin, HEX 70a, were also detected in ovaries and testes. Aiming to identify the subcellular localization of HEX 70a in the female and male gonads, we used a specific antibody in whole mount preparations of ovaries and testes for analysis by confocal laser-scanning microscopy. Intranuclear HEX 70a foci were evidenced in germ and somatic cells of Ovarioles and testioles of pharate-adult workers and drones, suggesting a regulatory or structural role. Following injection of the thymidine analog EdU we observed co-labeling with HEX 70a in ovariole cell nuclei, inferring possible HEX 70a involvement in cell proliferation. Further support to this hypothesis came from an injection of anti-HEX 70a into newly ecdysed queen pupae where it had a negative effect on ovariole thickening. HEX 70a foci were also detected in Ovarioles of egg laying queens, particularly in the nuclei of the highly polyploid nurse cells and in proliferating follicle cells. Additional roles for this storage protein are indicated by the detection of nuclear HEX 70a foci in post-meiotic spermatids and spermatozoa. Taken together, these results imply undescribed roles for HEX 70a in the developing gonads of the honey bee and raise the possibility that other hexamerins may also have tissue specific functions.
Teresa Szklarzewicz - One of the best experts on this subject based on the ideXlab platform.
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Symbiotic microorganisms in Puto superbus (Leonardi, 1907) (Insecta, Hemiptera, Coccomorpha: Putoidae).
Protoplasma, 2017Co-Authors: Teresa Szklarzewicz, Władysława Jankowska, Małgorzata Kalandyk-kołodziejczyk, Katarzyna Michalik, Anna MichalikAbstract:The scale insect Puto superbus (Putoidae) lives in mutualistic symbiotic association with bacteria. Molecular phylogenetic analyses have revealed that symbionts of P. superbus belong to the gammaproteobacterial genus Sodalis. In the adult females, symbionts occur both in the bacteriocytes constituting compact bacteriomes and in individual bacteriocytes, which are dispersed among Ovarioles. The bacteriocytes also house a few small, rod-shaped Wolbachia bacteria in addition to the numerous large, elongated Sodalis-allied bacteria. The symbiotic microorganisms are transovarially transmitted from generation to generation. In adult females which have choriogenic oocytes in the Ovarioles, the bacteriocytes gather around the basal part of the tropharium. Next, the entire bacteriocytes pass through the follicular epithelium surrounding the neck region of the ovariole and enter the space between oocyte and follicular epithelium (perivitelline space). In the perivitelline space, the bacteriocytes assemble extracellularly in the deep depression of the oolemma at the anterior pole of the oocyte, forming a “symbiont ball”.
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the ovaries of aphids hemiptera sternorrhyncha aphidoidea morphology and phylogenetic implications
Invertebrate Biology, 2013Co-Authors: Anna Michalik, Teresa Szklarzewicz, Piotr Wegierek, Karina WieczorekAbstract:The ovaries of aphids belonging to the families Eriosomatidae, Anoeciidae, Drepanosiphidae, Thelaxidae, Aphididae, and Lachnidae were examined at the ultrastructural level. The ovaries of these aphids are composed of several telotrophic Ovarioles. The individual ovariole is differentiated into a terminal filament, tropharium, vitellarium, and pedicel (ovariolar stalk). Terminal filaments of all Ovarioles join together into the suspensory ligament, which attaches the ovary to the lobe of the fat body. The tropharium houses individual trophocytes and early previtellogenic oocytes termed arrested oocytes. Trophocytes are connected with the central part of the tropharium, the trophic core, by means of broad cytoplasmic processes. One or more oocytes develop in the vitellarium. Oocytes are surrounded by a single layer of follicular cells, which do not diversify into distinct subpopulations. The general organization of the ovaries in oviparous females is similar to that of the ovaries in viviparous females, but there are significant differences in their functioning: (1) in viviparous females, all Ovarioles develop, whereas in oviparous females, some of them degenerate; (2) the number of germ cells per ovariole is usually greater in females of the oviparous generation than in females of viviparous generations; (3) in oviparous females, oocytes in the vitellarium develop through three stages (previtellogenesis, vitellogenesis, and choriogenesis), whereas in viviparous females, the development of oocytes stops after previtellogenesis; and (4) in the oocyte cytoplasm of oviparous females, lipid droplets and yolk granules accumulate, whereas in viviparous females, oocytes accrue only lipid droplets. Our results indicate that a large number of germ cells per ovariole represent the ancestral state within aphids. This trait may be helpful in inferring the phylogeny of Aphidoidea.
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Ovaries of Puto superbus and Ceroputo pilosellae (Hemiptera: Coccoidea): Morphology, ultrastructure, phylogenetic and taxonomic implications
European Journal of Entomology, 2013Co-Authors: Anna Michalik, Małgorzata Kalandyk-kołodziejczyk, Ewa Simon, Michał Kobiałka, Teresa SzklarzewiczAbstract:Ovaries of Puto superbus and Ceroputo pilosellae are composed of numerous short telotrophic Ovarioles that are arranged around the distal part of the lateral oviduct. An individual ovariole consists of a distal trophic chamber (= tropharium) and proximal vitellarium. The tropharia enclose individual trophocytes (= nurse cells) and early previtellogenic oocytes termed arrested oocytes. A single oocyte develops in each vitellarium. Analysis of serial sections has shown that Ovarioles of P. superbus contain from 16 to 51 germ cells (13-43 trophocytes, 2-7 arrested oocytes, 1 developing oocyte) while those of C. pilosellae from only 8 to 10 germ cells (5-7 trophocytes, 0-2 arrested oocytes, 1 developing oocyte). The classification and phylogeny of scale insects are discussed taking into consideration the results of this study.
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ovary structure and transovarial transmission of endosymbiotic microorganisms in marchalina hellenica insecta hemiptera coccomorpha marchalinidae
Acta Zoologica, 2013Co-Authors: Teresa Szklarzewicz, Malgorzata Kalandykkolodziejczyk, Marta Kot, Anna MichalikAbstract:Szklarzewicz, T., Kalandyk-Kolodziejczyk, M., Kot, M. and Michalik, A. 2011. Ovary structure and transovarial transmission of endosymbiotic microorganisms in Marchalina hellenica (Insecta, Hemiptera, Coccomorpha: Marchalinidae). —Acta Zoologica (Stockholm) 00:1–9. The paired ovaries of Marchalina hellenica are composed of about 200 Ovarioles of telotrophic type. In each ovariole, a trophic chamber, vitellarium and ovariolar stalk can be distinguished. The tropharia comprise trophocytes and early previtellogenic oocytes (termed arrested oocytes) or trophocytes only. The arrested oocytes are not capable of further development. In the vitellaria, single oocytes develop that are connected to the tropharium by means of broad nutritive cords. The number of germ cells (trophocytes and oocytes) constituting Ovarioles is not constant and may range between 25 and 32. Numerous endosymbiotic bacteria occur in the cytoplasm of trophocytes. The endosymbionts are transported via nutritive cords to the developing oocyte. The obtained results are discussed in a phylogenetic context.
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Ultrastructure, distribution, and transovarial transmission of symbiotic microorganisms in Nysius ericae and Nithecus jacobaeae (Heteroptera: Lygaeidae: Orsillinae).
Protoplasma, 2012Co-Authors: Malgorzata Swiatoniowska, Aniela Gołas, Antoni Ogorzalek, Teresa SzklarzewiczAbstract:The organization of the symbiotic system (i.e., distribution and ultrastructure of symbionts) and the mode of inheritance of symbionts in two species, Nysius ericae and Nithecus jacobaeae belonging to Heteroptera: Lygaeidae, are described. Like most hemipterans, Nysius ericae and Nithecus jacobaeae harbor obligate prokaryotic symbionts. The symbiotic bacteria are harbored in large, specialized cells termed bacteriocytes which are localized in the close vicinity of the ovaries as well as inside the ovaries. The ovaries are composed of seven Ovarioles of the telotrophic type. Bacteriocytes occur in each ovariole in the basal part of tropharium termed the infection zone. The bacteriocytes form a ring surrounding the early previtellogenic oocytes. The cytoplasm of the bacteriocytes is tightly packed with large elongated bacteria. In the bacteriocytes of Nysius ericae, small, rod-shaped bacteria also occur. Both types of bacteria are transovarially transmitted from one generation to the next.
Anna Michalik - One of the best experts on this subject based on the ideXlab platform.
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Symbiotic microorganisms in Puto superbus (Leonardi, 1907) (Insecta, Hemiptera, Coccomorpha: Putoidae).
Protoplasma, 2017Co-Authors: Teresa Szklarzewicz, Władysława Jankowska, Małgorzata Kalandyk-kołodziejczyk, Katarzyna Michalik, Anna MichalikAbstract:The scale insect Puto superbus (Putoidae) lives in mutualistic symbiotic association with bacteria. Molecular phylogenetic analyses have revealed that symbionts of P. superbus belong to the gammaproteobacterial genus Sodalis. In the adult females, symbionts occur both in the bacteriocytes constituting compact bacteriomes and in individual bacteriocytes, which are dispersed among Ovarioles. The bacteriocytes also house a few small, rod-shaped Wolbachia bacteria in addition to the numerous large, elongated Sodalis-allied bacteria. The symbiotic microorganisms are transovarially transmitted from generation to generation. In adult females which have choriogenic oocytes in the Ovarioles, the bacteriocytes gather around the basal part of the tropharium. Next, the entire bacteriocytes pass through the follicular epithelium surrounding the neck region of the ovariole and enter the space between oocyte and follicular epithelium (perivitelline space). In the perivitelline space, the bacteriocytes assemble extracellularly in the deep depression of the oolemma at the anterior pole of the oocyte, forming a “symbiont ball”.
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the ovaries of aphids hemiptera sternorrhyncha aphidoidea morphology and phylogenetic implications
Invertebrate Biology, 2013Co-Authors: Anna Michalik, Teresa Szklarzewicz, Piotr Wegierek, Karina WieczorekAbstract:The ovaries of aphids belonging to the families Eriosomatidae, Anoeciidae, Drepanosiphidae, Thelaxidae, Aphididae, and Lachnidae were examined at the ultrastructural level. The ovaries of these aphids are composed of several telotrophic Ovarioles. The individual ovariole is differentiated into a terminal filament, tropharium, vitellarium, and pedicel (ovariolar stalk). Terminal filaments of all Ovarioles join together into the suspensory ligament, which attaches the ovary to the lobe of the fat body. The tropharium houses individual trophocytes and early previtellogenic oocytes termed arrested oocytes. Trophocytes are connected with the central part of the tropharium, the trophic core, by means of broad cytoplasmic processes. One or more oocytes develop in the vitellarium. Oocytes are surrounded by a single layer of follicular cells, which do not diversify into distinct subpopulations. The general organization of the ovaries in oviparous females is similar to that of the ovaries in viviparous females, but there are significant differences in their functioning: (1) in viviparous females, all Ovarioles develop, whereas in oviparous females, some of them degenerate; (2) the number of germ cells per ovariole is usually greater in females of the oviparous generation than in females of viviparous generations; (3) in oviparous females, oocytes in the vitellarium develop through three stages (previtellogenesis, vitellogenesis, and choriogenesis), whereas in viviparous females, the development of oocytes stops after previtellogenesis; and (4) in the oocyte cytoplasm of oviparous females, lipid droplets and yolk granules accumulate, whereas in viviparous females, oocytes accrue only lipid droplets. Our results indicate that a large number of germ cells per ovariole represent the ancestral state within aphids. This trait may be helpful in inferring the phylogeny of Aphidoidea.
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Ovaries of Puto superbus and Ceroputo pilosellae (Hemiptera: Coccoidea): Morphology, ultrastructure, phylogenetic and taxonomic implications
European Journal of Entomology, 2013Co-Authors: Anna Michalik, Małgorzata Kalandyk-kołodziejczyk, Ewa Simon, Michał Kobiałka, Teresa SzklarzewiczAbstract:Ovaries of Puto superbus and Ceroputo pilosellae are composed of numerous short telotrophic Ovarioles that are arranged around the distal part of the lateral oviduct. An individual ovariole consists of a distal trophic chamber (= tropharium) and proximal vitellarium. The tropharia enclose individual trophocytes (= nurse cells) and early previtellogenic oocytes termed arrested oocytes. A single oocyte develops in each vitellarium. Analysis of serial sections has shown that Ovarioles of P. superbus contain from 16 to 51 germ cells (13-43 trophocytes, 2-7 arrested oocytes, 1 developing oocyte) while those of C. pilosellae from only 8 to 10 germ cells (5-7 trophocytes, 0-2 arrested oocytes, 1 developing oocyte). The classification and phylogeny of scale insects are discussed taking into consideration the results of this study.
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ovary structure and transovarial transmission of endosymbiotic microorganisms in marchalina hellenica insecta hemiptera coccomorpha marchalinidae
Acta Zoologica, 2013Co-Authors: Teresa Szklarzewicz, Malgorzata Kalandykkolodziejczyk, Marta Kot, Anna MichalikAbstract:Szklarzewicz, T., Kalandyk-Kolodziejczyk, M., Kot, M. and Michalik, A. 2011. Ovary structure and transovarial transmission of endosymbiotic microorganisms in Marchalina hellenica (Insecta, Hemiptera, Coccomorpha: Marchalinidae). —Acta Zoologica (Stockholm) 00:1–9. The paired ovaries of Marchalina hellenica are composed of about 200 Ovarioles of telotrophic type. In each ovariole, a trophic chamber, vitellarium and ovariolar stalk can be distinguished. The tropharia comprise trophocytes and early previtellogenic oocytes (termed arrested oocytes) or trophocytes only. The arrested oocytes are not capable of further development. In the vitellaria, single oocytes develop that are connected to the tropharium by means of broad nutritive cords. The number of germ cells (trophocytes and oocytes) constituting Ovarioles is not constant and may range between 25 and 32. Numerous endosymbiotic bacteria occur in the cytoplasm of trophocytes. The endosymbionts are transported via nutritive cords to the developing oocyte. The obtained results are discussed in a phylogenetic context.
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Germ cell cluster formation and ovariole structure in Puto albicans and Crypticerya morrilli (Hemiptera: Coccinea). Phylogenetic implications
European Journal of Entomology, 2010Co-Authors: Teresa Szklarzewicz, Anna Michalik, Anna Czaja, Sylwia SzydlowskaAbstract:The organization and development of ovaries in representatives of two families (Putoidae and Monophlebidae) of scale insects are described. Developing ovaries of Puto albicans McKenzie, 1967 and Crypticerya morrilli (Cockerell, 1914) consist of numerous clusters of cystocytes that are arranged in the form of rosettes. At the end of the last nymphal instar these clusters start to protrude from the interior of the ovary into the body cavity and the Ovarioles begin to be formed. The ovary of a young female is composed of about 200 spherical telotrophic Ovarioles devoid of terminal filaments. The Ovarioles of C. morrilli contain 8 germ cells (7 trophocytes and a single oocyte). From 25 to 45 germ cells (23-43 trophocytes and 2 or 3 oocytes) occur in the Ovarioles of P. albicans. An ovariole of an adult female is subdivided into a trophic chamber (tropharium), vitellarium and ovariolar stalk (pedicel). At each stage of development, the ovaries are accompanied by large cells (termed bacteriocytes) that contain endosymbiotic microorganisms. The organization of the ovary in P. albicans is more similar to that in archaeococcoid scale insects than in neococcoid taxa. In contrast, the number of germ cells per ovariole in C. morrilli is not typical of other archaeococcoids, but resembles the derived condition seen in other iceryine taxa. The classification and phylogeny of scale insects are discussed in the light of these results.
Klaus Hartfelder - One of the best experts on this subject based on the ideXlab platform.
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ovariole number a predictor of differential reproductive success among worker subfamilies in queenless honeybee apis mellifera l colonies
Behavioral Ecology and Sociobiology, 2006Co-Authors: Gustavo R Makert, Robert J Paxton, Klaus HartfelderAbstract:A honeybee queen normally mates with 10–20 drones, and reproductive conflicts may arise among a colony’s different worker patrilines, especially after a colony has lost its single queen and the workers commence egg laying. In this study, we employed microsatellite markers to study aspects of worker reproductive competition in two queenless Africanized honeybee colonies. First, we determined whether there was a bias among worker patrilines in their maternity of drones and, second, we asked whether this bias could be attributed to differences in the degree of ovary activation of workers. Third, we relate these behavioral and physiological factors to ontogenetic differences between workers with respect to ovariole number. Workers from each of three (colony A) and one (colony B) patrilineal genotypes represented less than 6% of the worker population, yet each produced at least 13% of the drones in a colony, and collectively they produced 73% of the drones. Workers representing these genotypes also had more developed follicles and a greater number of Ovarioles per ovary. Across all workers, ovariole development and number were closely correlated. This suggests a strong effect of worker genotype on the development of the ovary already in the postembryonic stages and sets a precedent to adult fertility, so that “workers are not born equal”. We hypothesize a frequency-dependent or “rare patriline” advantage to queenless workers over the parentage of males and discuss the maintenance of genetic variance in the reproductive capacity of workers.
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the initial stages of oogenesis and their relation to differential fertility in the honey bee apis mellifera castes
Arthropod Structure & Development, 2004Co-Authors: Erica D Tanaka, Klaus HartfelderAbstract:Abstract Neither the overall differences in ovariole number nor the caste-specifically modulated expression of vitellogenin can fully explain the striking caste differences in honey bee reproduction, in particular the mechanisms that block oogenesis in virgin queens and in workers kept in the presence of a queen. For this reason we investigated the initial stages of oogenesis in queens in relation to mating status and in workers exposed to different social conditions. A striking feature in Ovarioles of both castes was a considerably elongated terminal filament which consisted not only of normal terminal filament cells but also contained apparently undifferentiated cells that were tentatively considered as stem cells. BrdU incorporation was detected in the upper germarium, as well as in the terminal filament. Cytoskeleton analysis by TRITC-phalloidin labeling for F-actin, and immunofluorescence detection for β-tubulin did not reveal structural differences in the early oogenesis steps between queens and queenless workers. In contrast, queenright workers showed signs of a disorganized microtubule and microfilament system that could explain the histological evidence for progressive cell death observed in the germaria. In addition to cytoplasmic tubulin we also detected marked intranuclear foci indicating the presence of nuclear βII-tubulin.
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caste determination is a sequential process effect of larval age at grafting on ovariole number hind leg size and cephalic volatiles in the honey bee apis mellifera carnica
Journal of Apicultural Research, 1998Co-Authors: Selim Dedej, Klaus Hartfelder, Pia Aumeier, Peter Rosenkranz, Wolf EngelsAbstract:SUMMARYArtificial queen rearing with worker larvae grafted at different developmental stages resulted in gradual effects on ovary size (number of Ovarioles per ovary), as well as hind leg and wax gland structures in adults. A significant decrease in ovariole number was observed when third instar larvae were grafted. Basitarsus shape was affected when fourth instar larvae were grafted. Queen—worker intermediates developed when early-fifth instar worker larvae were transferred. As newly emerged adults, spectra of cephalic volatiles of queens and workers are still very similar, and do not yet exhibit the caste-specific elements of the mandibular glands. At one day after emergence, most of the dominant compounds in these spectra are represented at higher levels in workers.
Cassandra G. Extavour - One of the best experts on this subject based on the ideXlab platform.
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topology driven protein protein interaction network analysis detects genetic sub networks regulating reproductive capacity
bioRxiv, 2020Co-Authors: Tarun Kumar, Leo Blondel, Cassandra G. ExtavourAbstract:Understanding the genetic regulation of organ structure is a fundamental problem in developmental biology. Here, we use egg-producing structures of insect ovaries, called Ovarioles, to deduce systems-level gene regulatory relationships from quantitative functional genetic analysis. We previously showed that Hippo signalling, a conserved regulator of animal organ size, regulates ovariole number in Drosophila melanogaster. To comprehensively determine how Hippo signalling interacts with other pathways in this regulation, we screened all known signalling pathway genes, and identified Hpo-dependent and Hpo-independent signalling requirements. Network analysis of known protein-protein interactions among screen results identified independent gene regulatory sub-networks regulating one or both of ovariole number and egg laying. These modules predict involvement of previously uncharacterised genes with higher accuracy than the original candidate screen. This shows that network analysis combining functional genetic and large-scale interaction data can predict function of novel genes regulating development.
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repeated loss of variation in insect ovary morphology highlights the role of developmental constraint in life history evolution
bioRxiv, 2020Co-Authors: Samuel H Church, Bruno A S De Medeiros, Seth Donoughe, Nicole Marquez L Reyes, Cassandra G. ExtavourAbstract:Abstract The number of offspring an organism can produce is a key component of its evolutionary fitness and lifehistory. Here we perform a test of the hypothesized trade off between the number and size of offspring using thousands of descriptions of the number of egg-producing compartments in the insect ovary (Ovarioles), a common proxy for potential offspring number in insects. In contrast to prior claims, we find that ovariole number is not generally negatively correlated with the size of insect eggs, and we highlight several factors that may have contributed to this size-number trade off being strongly asserted in previous studies. We reconstruct the evolutionary history of the nurse cell arrangement within the ovariole, and show that the diversification of ovariole number and egg size have both been largely independent of nurse cell presence or position within the ovariole. Instead we show that ovariole number evolution has been shaped by a series of transitions between variable and invariant states, with multiple independent lineages evolving to have almost no variation in ovariole number. We highlight the implications of these invariant lineages on our understanding of the specification of ovariole number during development, as well as the importance of considering developmental processes in theories of life-history evolution.
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topology driven analysis of protein protein interaction networks detects functional genetic modules regulating reproductive capacity
bioRxiv, 2019Co-Authors: Tarun Kumar, Leo Blondel, Cassandra G. ExtavourAbstract:Understanding the genetic regulation of organ structure is a fundamental problem in developmental biology. Here, we use egg-producing structures of insect ovaries, called Ovarioles, to deduce systems-level gene regulatory relationships from quantitative functional genetic analysis. We previously showed that Hippo signalling, a conserved regulator of animal organ size, regulates ovariole number in Drosophila melanogaster. To comprehensively determine how Hippo signalling interacts with other pathways in this regulation, we screened all identified signalling pathway genes, and identified Hpo-dependent and Hpo-independent signalling requirements. Network analysis of known protein-protein interactions among screen results identified independent gene regulatory modules regulating one or both of ovariole number and egg laying. These modules predict involvement of previously uncharacterised genes with higher accuracy than the original candidate screen. This shows that network analysis combining functional genetic and large-scale interaction data can predict function of novel genes regulating development.
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reproductive capacity evolves in response to ecology through common changes in cell number in hawaiian drosophila
Current Biology, 2019Co-Authors: Didem P. Sarikaya, Samuel H Church, Laura P. Lagomarsino, Steven L. Montgomery, Karl N. Magnacca, Donald K. Price, Kenenth Y. Kaneshiro, Cassandra G. ExtavourAbstract:Summary Lifetime reproductive capacity is a critical fitness component. In insects, female reproductive capacity is largely determined by the number of Ovarioles, the egg-producing subunits of the ovary [e.g., 1 ]. Recent work has provided insights into ovariole number regulation in Drosophila melanogaster. However, whether mechanisms discovered under laboratory conditions explain evolutionary variation in natural populations is an outstanding question. We investigated potential effects of ecology on the developmental processes underlying ovariole number evolution among Hawaiian Drosophila, a large adaptive radiation wherein the highest and lowest ovariole numbers of the family have evolved within 25 million years. Previous studies proposed that ovariole number correlated with oviposition substrate [ 2 , 3 , 4 ] but sampled largely one clade of these flies and were limited by a provisional phylogeny and the available comparative methods. We test this hypothesis by applying phylogenetic modeling to an expanded sampling of ovariole numbers and substrate types and show support for these predictions across all major groups of Hawaiian Drosophila, wherein ovariole number variation is best explained by adaptation to specific substrates. Furthermore, we show that oviposition substrate evolution is linked to changes in the allometric relationship between body size and ovariole number. Finally, we provide evidence that the major changes in ovarian cell number that regulate D. melanogaster ovariole number also regulate ovariole number in Hawaiian drosophilids. Thus, we provide evidence that this remarkable adaptive radiation is linked to evolutionary changes in a key reproductive trait regulated at least partly by variation in the same developmental parameters that operate in the model species D. melanogaster.