Papers by Silvia Gigliotti
The gametes are responsible for passing all the genetic information from one generation to anothe... more The gametes are responsible for passing all the genetic information from one generation to another, giving rise to all the tissues in a developing animal, and ultimately guaranteeing the survival of species. The formation of germ-line stem cells occurs during early development in all animals. The differentiation of these pluripotent cells into mature gametes provides a continuous supply of sperms and eggs during adult life. Many aspects of germ-line development are conserved across species. For example, in most metazoans, female primordial germ cells (PGCs) migrate from an extragonadal site of origin to reach the somatic gonad and to produce oocytes. After a mitotic proliferative stage, the primary oocytes enter meiosis. In most animal species this process is arrested during prophase, and is completed only in response to intercellular signaling or fertilization, which trigger oocyte meiotic maturation. After the arrest, the oocyte synthesizes and stores a large amount of mRNAs that ...
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This dataset represents raw data and metadata underlying the findings (and the figures) reported ... more This dataset represents raw data and metadata underlying the findings (and the figures) reported in the manuscript "A salivary chitinase of Varroa destructor regulates mite-honey bee interactions". <strong>Fig 2A.</strong> Relative expression data of 3 selected candidates are presented as mean fold changes of 3-4 independent biological replicates. Each replicate consisted of a pool of 5-10 mites, from which the RNA was extracted from, salivary glands (SG), and from the rest of the whole body, deprived of salivary glands (Whole Body – SG). Values on Y-axis are reported in Log<sub>10</sub> scale. Error bars represent standard error of the mean. Statistically significant differences are denoted with an asterisk (P < 0.005). <strong>Fig 4.</strong> <strong>Survival of <em>V. destructor</em> as affected by RNAi-mediated silencing of the gene encoding VdCHIsal. </strong>(A) Relative expression of <em>Vd-CHIsal&...
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Insect Biochem Molec Biol, 2007
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Experientia, 2010
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The study of Polydnaviruses (PDV) and of their genomes has attracted considerable research effort... more The study of Polydnaviruses (PDV) and of their genomes has attracted considerable research efforts in the last decade, which have allowed the completion of quite a few genome projects. To date, the genomes of the bracoviruses associated with Cotesia plutellae, Cotesia congregata and Microplitis demolitor have been fully sequenced, and, more recently, we have completed the genome sequence of Toxoneuron nigriceps bracovirus (TnBV). We will present the major findings of this work and of an in silico analysis which aims at identifying the promoter elements in the available bracovirus genomes, using a Drosophila melanogaster-based tool for promoter prediction (neural network promoter prediction). The comparative analysis performed sheds light on the conservation of the promoter elements during PDV evolution and provides information on the regulatory effects of the predicted elements on the expression profile of specific genes.
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Biology, 2022
All organisms, from bacteria to mammals, sense and respond to foreign nucleic acids to fight infe... more All organisms, from bacteria to mammals, sense and respond to foreign nucleic acids to fight infections in order to survive and preserve genome integrity across generations. The innate immune system is an evolutionarily conserved defence strategy. Complex organisms have developed various cellular processes to respond to and recognise not only infections, i.e., pathogen-associated molecular patterns (PAMPs), but also to sense injury and tissue dysfunctions, i.e., damage-associated molecular patterns (DAMPs). Mis-localized self-DNA can be sensed as DAMP by specific DNA-sensing pathways, and self-DNA chronic exposure can be detrimental to the organisms. Here, we investigate the effects of dietary delivered self-DNA in the nematode Caenorhabditis elegans. The hermaphrodite worms were fed on Escherichia coli genomic libraries: a C. elegans library (self) and a legume (Medicago truncatula) library (non-self). We show that the self-library diet affects embryogenesis, larval development and...
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Invertebrate Survival Journal, 2004
Gonadal development requires complex differentiation programs leading to the production offunctio... more Gonadal development requires complex differentiation programs leading to the production offunctional female and male gametes. Upon fertilization, while the male germ cell contributes to thenewly formed zygote only its genetic material, the female germ cell also supplies its cytoplasmiccomponents, including fundamental molecular cues on which early embryonic development will rely.Unravelling the mechanisms employed by animal species for building up their eggs is therefore achallenging task in developmental biology. As demonstrated by the impressive body of data producedin recent years, Drosophila melanogaster is a useful model system for attempting a step by stepdissection of the whole oogenesis process. Remarkable opportunities for comparative analyses are inturn expected to be provided by these studies, since it is becoming evident that conserved themesunderlie oogenesis in all animal species. In this review, we focus on few key differentiation eventsoccurring during egg chamber de...
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THE early stages of adult Drosophila melanogaster gametogenesis have common features in the two s... more THE early stages of adult Drosophila melanogaster gametogenesis have common features in the two sexes (for reviews see Fuller, 1993; Spradling, 1993). Germ line stem cells are located at the anterior tip of both ovaries and testes. Each germ line stem cell divides asymmetrically producing a stem cell and a sister cell that becomes the mitotic “founder ” of a 16-cell syncytial cyst. Somatic cell differentiation is different in the two sexes. In testes, stem cell–type division of two somatic progenitor cells generate two cyst cells that surround each newly formed primary spermatogonial cell. Signaling from germ Address all correspondence to Silvia Gigliotti, Istituto Internazionale di
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Genetics
Drosophila nup154 encodes a predicted nucleoporin homologous to yeast Nup170p, Nup157p, and verte... more Drosophila nup154 encodes a predicted nucleoporin homologous to yeast Nup170p, Nup157p, and vertebrate Nup155, all of which are major components of the nuclear pore complex (NPC). Unlike its yeast homologs, nup154 is essential for viability. Animals with strong loss-of-function nup154 mutations caused by P-element insertion in the 5′-UTR of the gene died as larvae with small discs, brains, and testes. nup154 mRNA expression appeared developmentally regulated in tissues of wild-type embryos, larvae, and adults, suggesting that new nup154 synthesis is required when assembly of new NPCs is required, as in proliferating or growing tissues. Two additional nup154 alleles also associated with different P-element inserts in the 5′-UTR were viable but had strong loss-of-function sterile phenotypes, including failure to maintain spermatogenic stem cells and failure to progress into vitellogenic stages of oogenesis. Lethality vs. viability correlated with orientation of the P-element inserts i...
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PLOS Pathogens
Varroa destructor is an ectoparasite of honey bees and an active disease vector, which represents... more Varroa destructor is an ectoparasite of honey bees and an active disease vector, which represents one of the most severe threats for the beekeeping industry. This parasitic mite feeds on the host’s body fluids through a wound in the cuticle, which allows food uptake by the mother mite and its progeny, offering a potential route of entrance for infecting microorganisms. Mite feeding is associated with saliva injection, whose role is still largely unknown. Here we try to fill this gap by identifying putative host regulation factors present in the saliva of V. destructor and performing a functional analysis for one of them, a chitinase (Vd-CHIsal) phylogenetically related to chitinases present in parasitic and predatory arthropods, which shows a specific and very high level of expression in the mite’s salivary glands. Vd-CHIsal is essential for effective mite feeding and survival, since it is apparently involved both in maintaining the feeding wound open and in preventing host infectio...
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Proceedings of the National Academy of Sciences, 2016
Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, s... more Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced nodulation response, which was associated with a significant enhancement of host larvae mortality triggered by B. thuringiensis and a Cry toxin. This was determined by an uncontrolled proliferation of midgut bacteria, after entering the body cavity through toxin-induced epithelial lesions. Consequ...
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Genetics, 2007
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Gene, 2010
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The Italian Journal of Biochemistry, Jul 1, 2003
Drosophila oogenesis is a complex developmental process involving the coordinated differentiation... more Drosophila oogenesis is a complex developmental process involving the coordinated differentiation of germ line and somatic cells. Correct execution and timing of cell fate specification and patterning events is achieved during this process by the integration of different cell-cell signalling pathways, eventually leading to the generation of positional information inside the oocyte, that is instrumental for the establishment of embryonic polarity. The large body of data accumulated at both cellular and molecular levels in the last decade clearly demonstrated how Drosophila oogenesis is a genetically tractable system particularly suited for the investigation of key developmental biology questions. Our recent contribution to the field relies on the characterisation of three different mutants named tegamino (teg), hold hup (hup) and tulipano (tip), identifying novel gene functions required during oogenesis. Specifically, teg is implicated in the morphogenesis of the follicular epithelium surrounding the germ line cells in the egg chamber, hup is involved in the establishment of egg chamber polarity and tip in the regulation of the dynamic germ cell chromatin organisation.
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Genetics, 1999
Drosophila nup154 encodes a predicted nucleoporin homologous to yeast Nup170p, Nup157p, and verte... more Drosophila nup154 encodes a predicted nucleoporin homologous to yeast Nup170p, Nup157p, and vertebrate Nup155, all of which are major components of the nuclear pore complex (NPC). Unlike its yeast homologs, nup154 is essential for viability. Animals with strong loss-of-function nup154 mutations caused by P-element insertion in the 5'-UTR of the gene died as larvae with small discs, brains, and testes. nup154 mRNA expression appeared developmentally regulated in tissues of wild-type embryos, larvae, and adults, suggesting that new nup154 synthesis is required when assembly of new NPCs is required, as in proliferating or growing tissues. Two additional nup154 alleles also associated with different P-element inserts in the 5'-UTR were viable but had strong loss-of-function sterile phenotypes, including failure to maintain spermatogenic stem cells and failure to progress into vitellogenic stages of oogenesis. Lethality vs. viability correlated with orientation of the P-element i...
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Gonadal development requires complex differentiation programs leading to the production of functi... more Gonadal development requires complex differentiation programs leading to the production of functional female and male gametes. Upon fertilization, while the male germ cell contributes to the newly formed zygote only its genetic material, the female germ cell also supplies its cytoplasmic components, including fundamental molecular cues on which early embryonic development will rely. Unravelling the mechanisms employed by animal species
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Mechanisms of Development, 1991
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Papers by Silvia Gigliotti