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1.
Int J Cancer ; 153(1): 173-182, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-36444499

RESUMEN

Chronic inflammation, linked to the presence of bovine milk and meat factors (BMMFs) and specific subsets of macrophages, results in oxygen radical synthesis and induction of mutations in DNA of actively replicating cells and replicating single stranded DNA. Cancers arising from this process have been characterized as indirect carcinogenesis by infectious agents (without persistence of genes of the agent in premalignant or cancers cells). Here, we investigate structural properties of pleomorphic vesicles, regularly identified by staining peritumor tissues of colorectal, lung and pancreatic cancer for expression of BMMF Rep. The latter represents a subgroup of BMMF1 proteins involved in replication of small single-stranded circular plasmids of BMMF, but most likely also contributing to pleomorphic vesicular structures found in the periphery of colorectal, lung and pancreatic cancers. Structurally dense regions are demonstrated in preselected areas of colorectal cancer, after staining with monoclonal antibodies against BMMF1 Rep. Similar structures were observed in human embryonic cells (HEK293TT) overexpressing Rep. These data suggest that Rep or Rep isoforms contribute to the structural formation of vesicles.


Asunto(s)
Neoplasias Colorrectales , Neoplasias Pancreáticas , Humanos , Animales , Leche , Replicación del ADN , Plásmidos , Neoplasias Pancreáticas/genética , Pulmón , Carne , Neoplasias Colorrectales/genética
2.
J Biol Chem ; 298(7): 102086, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35636513

RESUMEN

FMRFamide (Phe-Met-Arg-Phe-amide, FMRFa) and similar neuropeptides are important physiological modulators in most invertebrates, but the molecular basis of FMRFa activity at its receptors is unknown. We therefore sought to identify the molecular determinants of FMRFa potency against one of its native targets, the excitatory FMRFa-gated sodium channel (FaNaC) from gastropod mollusks. Using molecular phylogenetics and electrophysiological measurement of neuropeptide activity, we identified a broad FaNaC family that includes mollusk and annelid channels gated by FMRFa, FVRIamides, and/or Wamides (or myoinhibitory peptides). A comparative analysis of this broader FaNaC family and other channels from the overarching degenerin (DEG)/epithelial sodium channel (ENaC) superfamily, incorporating mutagenesis and experimental dissection of channel function, identified a pocket of amino acid residues that determines activation of FaNaCs by neuropeptides. Although this pocket has diverged in distantly related DEG/ENaC channels that are activated by other ligands but enhanced by FMRFa, such as mammalian acid-sensing ion channels, we show that it nonetheless contains residues that determine enhancement of those channels by similar peptides. This study thus identifies amino acid residues that determine FMRFa neuropeptide activity at FaNaC receptor channels and illuminates the evolution of ligand recognition in one branch of the DEG/ENaC superfamily of ion channels.


Asunto(s)
Neuropéptidos , Canales Iónicos Sensibles al Ácido , Aminoácidos , Animales , FMRFamida/metabolismo , Ligandos , Mamíferos/metabolismo , Moluscos/metabolismo , Neuropéptidos/genética , Neuropéptidos/metabolismo , Péptidos/metabolismo
3.
Cancers (Basel) ; 13(21)2021 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-34771570

RESUMEN

Exemplified by infections with bovine meat and milk factors (BMMFs), this manuscript emphasizes the different mechanistic aspects of infectious agents contributing to human cancers by "direct" or "indirect" interactions. The epidemiology of cancers linked to direct carcinogens (e.g., response to immunosuppression) differs from those cancers linked with indirect infectious interactions. Cancers induced by direct infectious carcinogens commonly increase under immunosuppression, whereas the cancer risk by indirect carcinogens is reduced. This influences their responses to preventive and therapeutic interferences. In addition, we discuss their role in colon, breast and prostate cancers and type II diabetes mellitus. A brief discussion covers the potential role of BMMF infections in acute myeloid leukemia.

4.
BMC Ecol Evol ; 21(1): 215, 2021 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-34844573

RESUMEN

BACKGROUND: The process of photoreception in most animals depends on the light induced isomerization of the chromophore retinal, bound to rhodopsin. To re-use retinal, the all-trans-retinal form needs to be re-isomerized to 11-cis-retinal, which can be achieved in different ways. In vertebrates, this mostly includes a stepwise enzymatic process called the visual cycle. The best studied re-isomerization system in protostomes is the rhodopsin-retinochrome system of cephalopods, which consists of rhodopsin, the photoisomerase retinochrome and the protein RALBP functioning as shuttle for retinal. In this study we investigate the expression of the rhodopsin-retinochrome system and functional components of the vertebrate visual cycle in a polyplacophoran mollusk, Leptochiton asellus, and examine the phylogenetic distribution of the individual components in other protostome animals. RESULTS: Tree-based orthology assignments revealed that orthologs of the cephalopod retinochrome and RALBP are present in mollusks outside of cephalopods. By mining our dataset for vertebrate visual cycle components, we also found orthologs of the retinoid binding protein RLBP1, in polyplacophoran mollusks, cephalopods and a phoronid. In situ hybridization and antibody staining revealed that L. asellus retinochrome is co-expressed in the larval chiton photoreceptor cells (PRCs) with the visual rhodopsin, RALBP and RLBP1. In addition, multiple retinal dehydrogenases are expressed in the PRCs, which might also contribute to the rhodopsin-retinochrome system. CONCLUSIONS: We conclude that the rhodopsin-retinochrome system is a common feature of mollusk PRCs and predates the origin of cephalopod eyes. Our results show that this system has to be extended by adding further components, which surprisingly, are shared with vertebrates.


Asunto(s)
Evolución Biológica , Cefalópodos , Pigmentos Retinianos , Rodopsina , Animales , Decapodiformes , Isomerismo , Filogenia , Retina , Rodopsina/genética
5.
Proc Natl Acad Sci U S A ; 118(12)2021 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-33723077

RESUMEN

Consumption of Eurasian bovine meat and milk has been associated with cancer development, in particular with colorectal cancer (CRC). In addition, zoonotic infectious agents from bovine products were proposed to cause colon cancer (zur Hausen et al., 2009). Bovine meat and milk factors (BMMF) are small episomal DNA molecules frequently isolated from bovine sera and milk products, and recently, also from colon cancer (de Villiers et al., 2019). BMMF are bioactive in human cells and were proposed to induce chronic inflammation in precancerous tissue leading to increased radical formation: for example, reactive oxygen and reactive nitrogen species and elevated levels of DNA mutations in replicating cells, such as cancer progenitor cells (zur Hausen et al., 2018). Mouse monoclonal antibodies against the replication (Rep) protein of H1MSB.1 (BMMF1) were used to analyze BMMF presence in different cohorts of CRC peritumor and tumor tissues and cancer-free individuals by immunohistochemistry and Western blot. BMMF DNA was isolated by laser microdissection from immunohistochemistry-positive tissue regions. We found BMMF Rep protein present specifically in close vicinity of CD68+ macrophages in the interstitial lamina propria adjacent to CRC tissues, suggesting the presence of local chronic inflammation. BMMF1 (modified H1MSB.1) DNA was isolated from the same tissue regions. Rep and CD68+ detection increased significantly in peritumor cancer tissues when compared to tissues of cancer-free individuals. This strengthens previous postulations that BMMF function as indirect carcinogens by inducing chronic inflammation and DNA damage in replicating cells, which represent progress to progenitor cells for adenoma (polyps) formation and cancer.


Asunto(s)
Antígenos CD/genética , Antígenos de Diferenciación Mielomonocítica/genética , Ácidos Nucleicos Libres de Células/genética , Ácidos Nucleicos Libres de Células/inmunología , Colitis/genética , Colitis/metabolismo , Neoplasias del Colon/genética , Neoplasias del Colon/metabolismo , Macrófagos/metabolismo , Animales , Biomarcadores , Bovinos , Susceptibilidad a Enfermedades , Técnica del Anticuerpo Fluorescente , Expresión Génica , Humanos , Inmunohistoquímica , Macrófagos/inmunología
6.
BMC Evol Biol ; 20(1): 117, 2020 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-32928118

RESUMEN

BACKGROUND: Nervous system development is an interplay of many processes: the formation of individual neurons, which depends on whole-body and local patterning processes, and the coordinated growth of neurites and synapse formation. While knowledge of neural patterning in several animal groups is increasing, data on pioneer neurons that create the early axonal scaffold are scarce. Here we studied the first steps of nervous system development in the annelid Malacoceros fuliginosus. RESULTS: We performed a dense expression profiling of a broad set of neural genes. We found that SoxB expression begins at 4 h postfertilization, and shortly later, the neuronal progenitors can be identified at the anterior and the posterior pole by the transient and dynamic expression of proneural genes. At 9 hpf, the first neuronal cells start differentiating, and we provide a detailed description of axonal outgrowth of the pioneer neurons that create the primary neuronal scaffold. Tracing back the clonal origin of the ventral nerve cord pioneer neuron revealed that it is a descendant of the blastomere 2d (2d221), which after 7 cleavages starts expressing Neurogenin, Acheate-Scute and NeuroD. CONCLUSIONS: We propose that an anterior and posterior origin of the nervous system is ancestral in annelids. We suggest that closer examination of the first pioneer neurons will be valuable in better understanding of nervous system development in spirally cleaving animals, to determine the potential role of cell-intrinsic properties in neuronal specification and to resolve the evolution of nervous systems.


Asunto(s)
Neurogénesis , Neuronas/citología , Poliquetos/citología , Animales , Poliquetos/enzimología
7.
Elife ; 92020 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-32880369

RESUMEN

Photoreceptor cells in the eyes of Bilateria are often classified into microvillar cells with rhabdomeric opsin and ciliary cells with ciliary opsin, each type having specialized molecular components and physiology. First data on the recently discovered xenopsin point towards a more complex situation in protostomes. In this study, we provide clear evidence that xenopsin enters cilia in the eye of the larval bryozoan Tricellaria inopinata and triggers phototaxis. As reported from a mollusc, we find xenopsin coexpressed with rhabdomeric-opsin in eye photoreceptor cells bearing both microvilli and cilia in larva of the annelid Malacoceros fuliginosus. This is the first organism known to have both xenopsin and ciliary opsin, showing that these opsins are not necessarily mutually exclusive. Compiling existing data, we propose that xenopsin may play an important role in many protostome eyes and provides new insights into the function, evolution, and possible plasticity of animal eye photoreceptor cells.


Asunto(s)
Evolución Molecular , Ojo , Opsinas , Péptidos , Células Fotorreceptoras de Invertebrados , Proteínas de Xenopus , Animales , Briozoos/química , Briozoos/genética , Briozoos/metabolismo , Cilios/química , Cilios/genética , Cilios/metabolismo , Ojo/química , Ojo/metabolismo , Larva/química , Larva/genética , Larva/metabolismo , Opsinas/química , Opsinas/genética , Opsinas/metabolismo , Péptidos/química , Péptidos/genética , Péptidos/metabolismo , Células Fotorreceptoras de Invertebrados/química , Células Fotorreceptoras de Invertebrados/metabolismo , Poliquetos/química , Poliquetos/genética , Poliquetos/metabolismo , Proteínas de Xenopus/química , Proteínas de Xenopus/genética , Proteínas de Xenopus/metabolismo
8.
Annu Rev Virol ; 6(1): 1-28, 2019 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-31567062

RESUMEN

This review briefly covers periods of my early life; experiences during World War II; my school education; and my period as a medical student in Bonn, Hamburg, and Düsseldorf. Mainly emphasized is my scientific career after finishing my medical internship and periods as a postdoc at the Institute for Microbiology in Düsseldorf and the Virus Laboratories of the Children's Hospital of Philadelphia and as Senior Research Fellow at the Institute of Virology in Würzburg, Germany. Subsequent appointment as chairman of the newly established Institute of Virology, University of Erlangen-Nürnberg, in a similar position at the University of Freiburg, and then for 20 years as scientific director of the Deutsches Krebsforschungszentrum, Heidelberg, are discussed, covering the scientific developments during these periods. The emeritus period since 2003 was particularly exciting, leading to the discovery of autonomously replicating plasmids, derived from specific bacteria, and their link to common human cancers (colon, breast, and prostate).


Asunto(s)
Neoplasias , Virus , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Investigación
9.
Emerg Microbes Infect ; 8(1): 1205-1218, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31409221

RESUMEN

The in silico analyses of 109 replication-competent genomic DNA sequences isolated from cow milk and its products (97 in the bovine meat and milk factors 2 group - BMMF2, and additional 4 in BMMF1) seems to place these in a specific class of infectious agents spanning between bacterial plasmid and circular ssDNA viruses. Satellite-type small plasmids with partial homology to larger genomes, were also isolated in both groups. A member of the BMMF1 group H1MBS.1 was recovered in a distinctly modified form from colon tissue by laser microdissection. Although the evolutionary origin is unknown, it draws the attention to the existence of a hitherto unrecognized, broad spectrum of potential pathogens. Indirect hints to the origin and structure of our isolates, as well as to their replicative behaviour, result from parallels drawn to the Hepatitis deltavirus genome structure and replication.


Asunto(s)
Neoplasias del Colon/virología , Virus ADN/aislamiento & purificación , Productos Lácteos/virología , Leche/virología , Suero/virología , Virus no Clasificados/aislamiento & purificación , Animales , Bovinos , Virus ADN/genética , Humanos , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Virus no Clasificados/genética
10.
Acta Crystallogr D Struct Biol ; 75(Pt 5): 498-504, 2019 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-31063152

RESUMEN

Bovine meat and milk factors (BMMFs) are circular, single-stranded episomal DNAs that have been detected in bovine meat and milk products. BMMFs are thought to have roles in human malignant and degenerative diseases. BMMFs encode a replication initiator protein (Rep) that is actively transcribed and translated in human cells. In this study, a Rep WH1 domain encoded on a BMMF (MSBI1.176) isolated from a multiple sclerosis human brain sample was determined to 1.53 Šresolution using X-ray crystallography. The overall structure of the MSBI1.176 WH1 domain was remarkably similar to other Rep structures, despite having a low (28%) amino-acid sequence identity. The MSBI1.176 WH1 domain contained elements common to other Reps, including five α-helices, five ß-strands and a hydrophobic pocket. These new findings suggest that the MSBI1.176 Rep might have comparable roles and functions to other known Reps of different origins.


Asunto(s)
Encéfalo/metabolismo , ADN Helicasas/química , ADN Helicasas/metabolismo , Esclerosis Múltiple/metabolismo , Plásmidos/aislamiento & purificación , Plásmidos/metabolismo , Transactivadores/química , Transactivadores/metabolismo , Secuencia de Aminoácidos , Animales , Bovinos , Cristalografía por Rayos X , Humanos , Modelos Moleculares , Unión Proteica , Conformación Proteica , Dominios Proteicos , Homología de Secuencia
12.
Mol Oncol ; 12(11): 1829-1837, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30241109

RESUMEN

The European Academy of Cancer Sciences (EACS) is an independent advisory body of well-recognised medical specialists and researchers striving to create a compelling interactive continuum of cancer research, from innovative basic research to implementation of state-of-the-art evidence-based cancer care and prevention. Achieving the above will entail bridging high-quality basic and preclinical cancer research to research on prevention, early detection and therapeutics as well as improving coordination of translational research efforts across Europe. The latter is expected to be expedited through quality assuring translational cancer research in Comprehensive Cancer Centres - entities that link research with the healthcare system - and networks of cancer research centres. Achieving a critical mass of expertise, resources and patients is crucial. Improving late translational research, which involves clinical studies to assess effectiveness, and added value for the health care is also a high priority. Both high-quality Big Data collections and the intelligent use of these data will promote innovation in cancer research and support outcomes research to assess clinical utility, quality of cancer care and long-term follow-up of treated patients. The EACS supports the mission-oriented approach recently proposed by the European Commission in Horizon Europe to deal with major challenges and would like to persuade the EU and its member states to formally launch a mission in cancer to boost and streamline the cancer research continuum in Europe. Building a coherent translational cancer research continuum with a focus on patients and individuals at risk will require, however, foresight as well as the extensive and continuous provision of evidence-based advice to inform policy.


Asunto(s)
Academias e Institutos , Atención a la Salud , Neoplasias , Investigación Biomédica Traslacional , Europa (Continente) , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Neoplasias/terapia
13.
BMC Dev Biol ; 18(1): 4, 2018 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-29486709

RESUMEN

BACKGROUND: Germ cell formation has been investigated in sessile forms of tunicates. This process involves the release of a subset of maternal transcripts from the centrosome-attracting body (CAB) in the progenitor cells of the germ line. When germ-soma segregation is completed, CAB structures are missing from the newly formed primordial germ cells (PGCs). In free-swimming tunicates, knowledge about germ cell formation is lacking. In this investigation, comparative gene expression and electron microscopy studies were used to address germ cell formation in Oikopleura dioica (O. dioica). RESULTS: We found that the RNA localization pattern of pumilio (pum1) is similar to the pattern described for a subset of maternal transcripts marking the posterior end of ascidian embryos. Transcripts marking the posterior end are called postplasmic or posterior-end mark (PEM) transcripts. We found no localization of vasa (vas) transcripts to any sub-region within the germ-line precursor cells. Expression of vas4 was detected in the newly formed PGCs. Electron microscopy studies confirmed the presence of structures with similar morphology to CAB. In the same cytoplasmic compartment, we also identified pum1 transcripts and an epitope recognized by an antibody to histone H3 phosphorylated on serine 28. CONCLUSIONS: Our findings support that a CAB-like structure participates in the segregation of maternal pum1 transcripts during germ-soma separation in O. dioica.


Asunto(s)
Centrosoma/metabolismo , Embrión no Mamífero/metabolismo , Desarrollo Embrionario , Células Germinativas/metabolismo , Urocordados/embriología , Animales , Centrosoma/ultraestructura , Gastrulación/genética , Regulación del Desarrollo de la Expresión Génica , Células Germinativas/citología , Células Germinativas/ultraestructura , Mitosis/genética , Modelos Biológicos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcripción Genética , Urocordados/citología , Cigoto/metabolismo
15.
Elife ; 62017 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-28876222

RESUMEN

Ciliary and rhabdomeric opsins are employed by different kinds of photoreceptor cells, such as ciliary vertebrate rods and cones or protostome microvillar eye photoreceptors, that have specialized structures and molecular physiologies. We report unprecedented cellular co-expression of rhabdomeric opsin and a visual pigment of the recently described xenopsins in larval eyes of a mollusk. The photoreceptors bear both microvilli and cilia and express proteins that are orthologous to transporters in microvillar and ciliary opsin trafficking. Highly conserved but distinct gene structures suggest that xenopsins and ciliary opsins are of independent origin, irrespective of their mutually exclusive distribution in animals. Furthermore, we propose that frequent opsin gene loss had a large influence on the evolution, organization and function of brain and eye photoreceptor cells in bilaterian animals. The presence of xenopsin in eyes of even different design might be due to a common origin and initial employment of this protein in a highly plastic photoreceptor cell type of mixed microvillar/ciliary organization.


Asunto(s)
Ojo/citología , Moluscos/fisiología , Opsinas/metabolismo , Péptidos/metabolismo , Células Fotorreceptoras/metabolismo , Proteínas de Xenopus/metabolismo , Animales , Larva/fisiología , Redes y Vías Metabólicas
16.
Proc Biol Sci ; 284(1859)2017 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-28724733

RESUMEN

Bilaterians usually possess a central nervous system, composed of neurons and supportive cells called glial cells. Whereas neuronal cells are highly comparable in all these animals, glial cells apparently differ, and in deuterostomes, radial glial cells are found. These particular secretory glial cells may represent the archetype of all (macro) glial cells and have not been reported from protostomes so far. This has caused controversial discussions of whether glial cells represent a homologous bilaterian characteristic or whether they (and thus, centralized nervous systems) evolved convergently in the two main clades of bilaterians. By using histology, transmission electron microscopy, immunolabelling and whole-mount in situ hybridization, we show here that protostomes also possess radial glia-like cells, which are very likely to be homologous to those of deuterostomes. Moreover, our antibody staining indicates that the secretory character of radial glial cells is maintained throughout their various evolutionary adaptations. This implies an early evolution of radial glial cells in the last common ancestor of Protostomia and Deuterostomia. Furthermore, it suggests that an intraepidermal nervous system-composed of sensory cells, neurons and radial glial cells-was probably the plesiomorphic condition in the bilaterian ancestor.


Asunto(s)
Evolución Biológica , Sistema Nervioso Central/citología , Células Ependimogliales/citología , Neuroglía/citología , Animales , Neuronas
17.
Genome Announc ; 5(17)2017 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-28450523

RESUMEN

Epidemiological data indicate a potential relationship between milk and dairy product consumption and the incidence of breast cancer, as well as neurodegenerative diseases. We report the isolation of two novel circular DNA molecules isolated from commercially available milk.

18.
Curr Top Microbiol Immunol ; 407: 83-116, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28349283

RESUMEN

Red meat and dairy products have frequently been suggested to represent risk factors for certain cancers, chronic neurodegenerative diseases, and autoimmune and cardiovascular disorders. This review summarizes the evidence and investigates the possible involvement of infectious factors in these diseases. The isolation of small circular single-stranded DNA molecules from serum and dairy products of Eurasian Aurochs (Bos taurus)-derived cattle, obviously persisting as episomes in infected cells, provides the basis for further investigations. Gene expression of these agents in human cells has been demonstrated, and frequent infection of humans is implicated by the detection of antibodies in a high percentage of healthy individuals. Epidemiological observations suggest their relationship to the development multiple sclerosis, to heterophile antibodies, and to N-glycolylneuraminic acid (Neu5Gc) containing cell surface receptors.


Asunto(s)
Enfermedad Crónica , Leche/microbiología , Neoplasias/microbiología , Carne Roja/microbiología , Animales , Anticuerpos/sangre , Bovinos , ADN Circular/análisis , ADN Circular/sangre , Humanos , Esclerosis Múltiple/epidemiología , Esclerosis Múltiple/microbiología , Plásmidos/análisis , Plásmidos/sangre , Receptores de Superficie Celular/química , Receptores de Superficie Celular/metabolismo
19.
BMC Evol Biol ; 16(1): 129, 2016 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-27306767

RESUMEN

BACKGROUND: Comparative investigations on bilaterian neurogenesis shed light on conserved developmental mechanisms across taxa. With respect to annelids, most studies focus on taxa deeply nested within the annelid tree, while investigations on early branching groups are almost lacking. According to recent phylogenomic data on annelid evolution Oweniidae represent one of the basally branching annelid clades. Oweniids are thought to exhibit several plesiomorphic characters, but are scarcely studied - a fact that might be caused by the unique morphology and unusual metamorphosis of the mitraria larva, which seems to be hardly comparable to other annelid larva. In our study, we compare the development of oweniid neuroarchitecture with that of other annelids aimed to figure out whether oweniids may represent suitable study subjects to unravel ancestral patterns of annelid neural development. Our study provides the first data on nervous system development in basally branching annelids. RESULTS: Based on histology, electron microscopy and immunohistochemical investigations we show that development and metamorphosis of the mitraria larva has many parallels to other annelids irrespective of the drastic changes in body shape during metamorphosis. Such significant changes ensuing metamorphosis are mainly from diminution of a huge larval blastocoel and not from major restructuring of body organization. The larval nervous system features a prominent apical organ formed by flask-shaped perikarya and circumesophageal connectives that interconnect the apical and trunk nervous systems, in addition to serially arranged clusters of perikarya showing 5-HT-LIR in the ventral nerve cord, and lateral nerves. Both 5-HT-LIR and FMRFamide-LIR are present in a distinct nerve ring underlying the equatorial ciliary band. The connections arising from these cells innervate the circumesophageal connectives as well as the larval brain via dorsal and ventral neurites. Notably, no distinct somata with 5-HT -LIR in the apical organ are detectable in the larval stages of Owenia. Most of the larval neural elements including parts of the apical organ are preserved during metamorphosis and contribute to the juvenile nervous system. CONCLUSIONS: Our studies in Owenia fusiformis strongly support that early branching annelids are comparable to other annelids with regard to larval neuroanatomy and formation of the juvenile nervous system. Therefore, Owenia fusiformis turns out to be a valuable study subject for comparative investigations and unravelling ancestral processes in neural development in Annelida and Bilateria in general.


Asunto(s)
Anélidos/anatomía & histología , Neurogénesis , Animales , Evolución Biológica , Larva/crecimiento & desarrollo , Modelos Biológicos , Sistema Nervioso/anatomía & histología , Poliquetos/anatomía & histología
20.
Evodevo ; 6: 40, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26702352

RESUMEN

BACKGROUND: Development of cerebral eyes is generally based on fine-tuned networks and closely intertwined with the formation of brain and head. Consistently and best studied in insects and vertebrates, many signaling pathways relaying the activity of eye developmental factors to positional information in the head region are characterized. Though known from several organisms, photoreceptors developing outside the head region are much less studied and the course of their development, relation to cerebral eyes and evolutionary origin is in most cases unknown. To explore how position influences development of otherwise similar photoreceptors, we analyzed the molecular characteristics of photoreceptors we discovered at the very anterior, the posttrochal mid-body and posterior body region of larval Leptochiton asellus, a representative of the chiton subgroup of mollusks. RESULTS: Irrespective of their position, all found photoreceptors exhibit a molecular signature highly similar to cerebral eye photoreceptors of related animals. All photoreceptors employ the same subtype of visual pigments (r-opsin), and the same key elements for phototransduction such as GNAq, trpC and arrestin and intracellular r-opsin transport such as rip11 and myosinV as described from other protostome cerebral eyes. Several transcription factors commonly involved in cerebral eye and brain development such as six1/2, eya, dachshund, lhx2/9 and prox are also expressed by all found photoreceptor cells, only pax6 being restricted to the anterior most cells. Coexpression of pax6 and MITF in photoreceptor-associated shielding pigment cells present at the mid-body position matches the common situation in cerebral eye retinal pigment epithelium specification and differentiation. Notably, all photoreceptors, even the posterior ones, further express clear anterior markers such as foxq2, irx, otx, and six3/6 (only the latter absent in the most posterior photoreceptors), which play important roles in the early patterning of the anterior neurogenic area throughout the animal kingdom. CONCLUSIONS: Our data suggest that anterior eyes with brain-associated development can indeed be subject to heterotopic replication to developmentally distinct and even posterior body regions. Retention of the transcriptional activity of a broad set of eye developmental factors and common anterior markers suggests a mode of eye development induction, which is largely independent of body regionalization.

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