Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 102
Filtrar
1.
Ecol Evol ; 13(12): e10818, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38089893

RESUMEN

Mechanisms of carrion insect succession have been interpreted separately from interspecific interactions between early and later colonists or from changes in volatile organic compounds perceived by insects resulting from the progression of decomposition. To link these perspectives, we examined through laboratory and field experiments whether the modification of volatile organic compounds by early colonists could be a mechanism of succession. In the laboratory experiment, we used Necrophila japonica (Coleoptera, Staphylinidae) as an early colonist and examined its effects on the emissions of important volatile attractants for carrion insects, dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) from carcasses. We collected DMDS and DMTS, using the static headspace method, under the following conditions: (i) rat carcass, (ii) rat carcass with artificial damage to the abdomen, (iii) rat carcass fed on by 10 Ne. japonica individuals, and (iv) 10 Ne. japonica individuals, and analyzed the collected gases using a gas chromatograph-mass spectrometer. After 12 and 30 h, carcasses fed on by Ne. japonica emitted higher concentrations of DMDS and DMTS than in other conditions. In the field experiment, we examined the effects of DMDS and DMTS on the attraction of carrion insects using traps baited with a mixture of DMDS and DMTS, hexane (odors unrelated to carcasses), or an empty microtube. Traps baited with DMDS and DMTS attracted more necrophagous species and individuals than traps not baited with this combination. These results showed that accelerated emissions of DMDS and DMTS from carcasses caused by early colonists may contribute to community assembly during carrion insect succession.

2.
Parasitol Res ; 122(8): 1795-1800, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37264281

RESUMEN

Eimeria spp. are protozoan parasites that are commonly found in a broad range of vertebrate hosts. These parasites generally exhibit strict host specificity, but some Eimeria spp. can infect groups of closely related species such as species within a genus or family. Compared with Eimeria spp. that infect livestock, limited information is available about such infections in wild animals including data on host specificity, virulence, and prevalence. The Japanese rock ptarmigan, Lagopus muta japonica, is an endangered bird belonging to the family Phasianidae, order Galliformes, and inhabits only alpine areas of Japan. In conservation efforts for these birds, two Eimeria spp., E. uekii and E. raichoi, were frequently detected. Here, we examined cross-transmission of the parasites to other bird species to characterize their infectivity as well as the development of experimental bird models to contribute to conservation programs by the oocyst transfer. Consequently, among the examined eight bird species (chickens, Japanese pheasants, turkeys, chukar partridges, quails, helmeted guineafowls and ducks), only turkeys (family Phasianidae, order Galliformes) could be infected with E. raichoi. However, the number of oocysts per feces was relatively low, and few parasites in the intestinal mucosa could be found by histopathological analyses. These results might indicate that E. uekii and E. raichoi are highly adapted to Japanese rock ptarmigans that inhabit the alpine zone although further studies are anticipated.


Asunto(s)
Animales Salvajes , Coccidiosis , Eimeria , Especies en Peligro de Extinción , Galliformes , Especificidad del Huésped , Animales , Pollos/parasitología , Coccidiosis/veterinaria , Coccidiosis/parasitología , Galliformes/parasitología , Oocistos , Codorniz/parasitología , Japón , Heces/parasitología , Animales Salvajes/parasitología , Patos/parasitología
3.
Sci Rep ; 11(1): 19294, 2021 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-34588496

RESUMEN

The raccoon (Procyon lotor) is an invasive carnivore that invaded various areas of the world. Although controlling feral raccoon populations is important to reduce serious threats to local ecosystems, raccoons are not under rigid population control in Europe and Japan. We examined the D-loop and nuclear microsatellite regions to identify spatially explicit and feasible management units for effective population control and further range expansion retardation. Through the identification of five mitochondrial DNA haplotypes and three nuclear genetic groups, we identified at least three independent introductions, range expansion, and subsequent genetic admixture in the Boso Peninsula. The management unit considered that two were appropriate because two populations have already genetic exchange. Furthermore, when taking management, we think that it is important to monitor DNA at the same time as capture measures for feasible management. This makes it possible to determine whether there is a invasion that has a significant impact on population growth from out of the unit, and enables adaptive management.


Asunto(s)
Especies Introducidas , Mapaches/genética , Animales , ADN Mitocondrial , Seguimiento de Parámetros Ecológicos/métodos , Ecosistema , Femenino , Variación Genética , Genética de Población , Haplotipos , Japón , Masculino , Repeticiones de Microsatélite
4.
Int J Parasitol Parasites Wildl ; 15: 225-230, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34159052

RESUMEN

Japanese rock ptarmigans, Lagopus muta japonica, are classified as an endangered species in Japan and are found only in the Japanese Alps. The number of birds has decreased in the last half century and cage protection projects have been undertaken as in situ conservation strategies (one of the projects for the recovery plan of Japanese rock ptarmigan) in the mountains. During the period with cage protections, some chicks died and two Eimeria spp., E. uekii and E. raichoi, were identified in the chicks. Here, we examined the soil within the cages and in the surrounding environment to assess potential sources of infection between July to August 2020. We found high numbers of oocysts in the cages, especially at the back sides where the ptarmigan family frequently congregated, but soils in other areas outside the cages were less contaminated or not contaminated at all. The time required for more than 50% of the oocysts to sporulate at 15, 20 and 25 °C for E. uekii was 20, 11, and 5 h, respectively, and 72, 48 and 18 h, respectively, for E. raichoi. Our results cast some doubt that coprophagia by chicks is the source of infection because chicks consumed fresh cecal feces (approximately within 1 h) as far as we know, and instead, the protected chicks might be directly or indirectly infected by oocysts in soils or the environment.

5.
Ecol Lett ; 24(3): 533-542, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33404198

RESUMEN

In ectothermic predator-prey relationships, evasion of predation by prey depends on physiological and behavioural responses relating to the thermal biology of both predator and prey. On Japan's Izu Islands, we investigated a prey lizard's physiological and thermal responses to the presence of a snake predator over geologic time in addition to recent climatic warming. Foraging lizard body temperatures increased by 1.3 °C from 1981 to 2019 overall, yet were 2.9 °C warmer on snake islands relative to snake-free islands. We also detected snake predator-induced selection on hind leg length, which in turn is a major determinant for sprint speed only in lizard populations exposed to predation by snakes. Accordingly, we found that warmer prey body temperatures result in faster sprint speeds by the prey at temperatures suboptimal for the snake predator, and therefore contribute to escaping predation. Given recent climatic change, further warming could irrevocably alter this and other ectothermic predator-prey relationships.


Asunto(s)
Lagartos , Animales , Temperatura Corporal , Cambio Climático , Islas , Conducta Predatoria
6.
Ecol Appl ; 31(3): e02261, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33219543

RESUMEN

Optimization of spatial resource allocation is crucial for the successful control of invasive species under a limited budget but requires labor-intensive surveys to estimate population parameters. In this study, we devised a novel framework for the spatially explicit optimization of capture effort allocation using state-space population models from past capture records. We applied it to a control program for invasive snapping turtles to determine effort allocation strategies that minimize the population density over the whole area. We found that spatially heterogeneous density dependence and capture pressure limit the abundance of snapping turtles. Optimal effort allocation effectively improved the control effect, but the degree of improvement varied substantially depending on the total effort. The degree of improvement by the spatial optimization of allocation effort was only 3.21% when the total effort was maintained at the 2016 level. However, when the total effort was increased by two, four, and eight times, spatial optimization resulted in improvements of 4.65%, 8.33%, and 20.35%, respectively. To achieve the management goal for snapping turtles in our study area, increasing the current total effort by more than four times was necessary, in addition to optimizing the spatial effort. The snapping turtle population is expected to reach the target density one year after the optimal management strategy is implemented, and this rapid response can be explained by high population growth rate coupled with density-dependent feedback regulation. Our results demonstrated that combining a state-space model with optimization makes it possible to adaptively improve the management of invasive species and decision-making. The method used in this study, based on removal records from an invasive management program, can be easily applied to monitoring data for wildlife and pest control management using traps in a variety of ecosystems.


Asunto(s)
Especies Introducidas , Tortugas , Animales , Animales Salvajes , Ecosistema , Control de Plagas , Densidad de Población
7.
Cell Rep ; 33(12): 108542, 2020 12 22.
Artículo en Inglés | MEDLINE | ID: mdl-33357423

RESUMEN

The extracellular adenosine triphosphate (ATP) concentration is highly elevated in the tumor microenvironment (TME) and remains tightly regulated in normal tissues. Using phage display technology, we establish a method to identify an antibody that can bind to an antigen only in the presence of ATP. Crystallography analysis reveals that ATP bound in between the antibody-antigen interface serves as a switch for antigen binding. In a transgenic mouse model overexpressing the antigen systemically, the ATP switch antibody binds to the antigen in tumors with minimal binding in normal tissues and plasma and inhibits tumor growth. Thus, we demonstrate that elevated extracellular ATP concentration can be exploited to specifically target the TME, giving therapeutic antibodies the ability to overcome on-target off-tumor toxicity.


Asunto(s)
Adenosina Trifosfato/metabolismo , Anticuerpos/metabolismo , Espacio Extracelular/metabolismo , Animales , Humanos , Ratones , Microambiente Tumoral
8.
Int J Parasitol Parasites Wildl ; 12: 19-24, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32368488

RESUMEN

The population of Japanese rock ptarmigan (Lagopus muta japonica), an endangered species with a habitat above the timberline of the southern Japanese Alps, has declined. As one of the recent conservation strategies for this species, cage protection for broods (hens and chicks) has been introduced in their habitats. Two species of Eimeria have frequently been detected in these birds, but little is known about the parasitic circulation in the region, including among birds and in the environment. Here, we conducted histopathology examinations of dead chicks collected under cage protection in 2018, and examined the feces of the hens and chicks of three broods and environmental soils for parasites in 2019 in order to assess the potential sources of infection and pathogenicity. Developmental zoites were found in the epithelial mucosa and/or the submucosa from the duodenum to the colon of all dead chicks. Fecal examination revealed oocysts of E. uekii and/or E. raichoi in all hens and chicks. Oocysts of Eimeria spp. per gram of feces in chicks increased within 2 weeks after hatching and then gradually deceased. Following infection of the chicks, oocysts could accumulate within the cage areas, and oocyst density exceeded more than 1000 oocysts per gram of cage soils. Based on having sporulated morphologies, oocysts could be infective and therefore, be direct or indirect potential sources of infection. However, based on our findings that not all chicks were clinically affected by the infections, other factors such as microbial flora in the chicks established by coprophagy or from the habitat environment, including climate, might be associated with the pathogenicity of Eimeria spp., although further studies are needed to assess these correlations.

9.
Cancer Res ; 79(22): 5734-5745, 2019 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-31391186

RESUMEN

Targeting genetic alterations of oncogenes by molecular-targeted agents (MTA) is an effective approach for treating cancer. However, there are still no clinical MTA options for many cancers, including esophageal cancer. We used a short hairpin RNA library to screen for a new oncogene in the esophageal cancer cell line KYSE70 and identified YES proto-oncogene 1 (YES1) as having a significant impact on tumor growth. An analysis of clinical samples showed that YES1 gene amplification existed not only in esophageal cancer but also in lung, head and neck, bladder, and other cancers, indicating that YES1 would be an attractive target for a cancer drug. Because there is no effective YES1 inhibitor so far, we generated a YES1 kinase inhibitor, CH6953755. YES1 kinase inhibition by CH6953755 led to antitumor activity against YES1-amplified cancers in vitro and in vivo. Yes-associated protein 1 (YAP1) played a role downstream of YES1 and contributed to the growth of YES1-amplified cancers. YES1 regulated YAP1 transcription activity by controlling its nuclear translocation and serine phosphorylation. These findings indicate that the regulation of YAP1 by YES1 plays an important role in YES1-amplified cancers and that CH6953755 has therapeutic potential in such cancers. SIGNIFICANCE: These findings identify the SRC family kinase YES1 as a targetable oncogene in esophageal cancer and describe a new inhibitor for YES1 that has potential for clinical utility.See related commentary by Rai, p. 5702.


Asunto(s)
Amplificación de Genes , Oncogenes , Línea Celular Tumoral , Genes src , Proteínas Proto-Oncogénicas c-yes
10.
Mol Cancer Ther ; 17(12): 2519-2529, 2018 12.
Artículo en Inglés | MEDLINE | ID: mdl-30242093

RESUMEN

Members of the tropomyosin receptor kinase (TRK) family are expressed in their constitutively activated forms as a result of a gene fusion that occurs across a wide variety of cancer types. We have identified CH7057288 as a potent and selective TRK inhibitor that belongs to a novel chemical class. CH7057288 showed selective inhibitory activity against TRKA, TRKB, and TRKC in cell-free kinase assays and suppressed proliferation of TRK fusion-positive cell lines, but not that of TRK-negative cell lines. Strong in vivo tumor growth inhibition was observed in subcutaneously implanted xenograft tumor models of TRK fusion-positive cells. Furthermore, in an intracranial implantation model mimicking brain metastasis, CH7057288 significantly induced tumor regression and improved event-free survival. Recently, resistant mutations in the kinase domain of TRK have been reported in patients who show disease progression after treatment with the TRK inhibitors now under clinical development. Our compound maintained similar levels of in vitro and in vivo activity against one of these resistant mutants as it did to wild-type TRK. An X-ray crystal structure of the TRKA and CH7057288 complex supported the activity against the mutant. In addition, gene expression analysis revealed that CH7057288 suppressed MAPK and E2F pathways as downstream signaling of TRK fusion. Therefore, CH7057288 could be a promising therapeutic agent for TRK fusion-positive cancer.


Asunto(s)
Benzofuranos/farmacología , Neoplasias/patología , Proteínas de Fusión Oncogénica/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Animales , Línea Celular Tumoral , Resistencia a Antineoplásicos/efectos de los fármacos , Femenino , Humanos , Ratones Endogámicos BALB C , Ratones Desnudos , Mutación/genética , Proteínas Quinasas/química , Transducción de Señal/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto
11.
J Morphol ; 279(1): 27-36, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28922458

RESUMEN

The developmental mechanisms of color patterns formation and its evolution remain unclear in reptilian sauropsids. We, therefore, studied the pigment cell mechanisms of stripe pattern formation during embryonic development of the snake Elaphe quadrivirgata. We identified 10 post-ovipositional embryonic developmental stages based on external morphological characteristics. Examination for the temporal changes in differentiation, distribution, and density of pigment cells during embryonic development revealed that melanophores first appeared in myotome and body cavity but not in skin surface at Stage 5. Epidermal melanophores were first recognized at Stage 7, and dermal melanophores and iridophores appeared in Stage 9. Stripe pattern first appeared to establish at Stage 8 as a spatial density gradient of epidermal melanophores between the regions of future dark brown longitudinal stripes and light colored background. Our study, thus, provides a comprehensive pigment-cell-based understanding of stripe pattern formation during embryonic development. We briefly discuss the importance of the gene expression studies by considering the biologically relevant theoretical models with standard developmental staging for understanding reptilian color pattern evolution.


Asunto(s)
Colubridae/anatomía & histología , Colubridae/embriología , Animales , Embrión no Mamífero/anatomía & histología , Desarrollo Embrionario , Melanóforos/citología , Pigmentación
12.
Int J Ment Health Nurs ; 27(2): 765-773, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28646495

RESUMEN

The present study reports the findings of a qualitative, descriptive study that sought to clarify nursing philosophy for community mental health nurses (CMHN) working at independent psychiatric home-visit nursing agencies in Japan. We carried out participant observation and semistructured interviews with 13 CMHN in rural and urban areas. We identified eight subthemes and three higher-order themes based on these subthemes. CMHN embraced a nursing philosophy in which they: (i) have respect for consumers' ways of life and their self-realization; (ii) find harmony between view of life and work; and (iii) build communities where residents support each other beyond their roles. Together, these themes constitute a valuable nursing philosophy that supports the recovery of people with mental illness. The themes could also help educate professionals about principles and meanings relevant to recovery, which are regarded as key to changing the professional's care paradigm from a biomedical model to a recovery model.


Asunto(s)
Enfermería en Salud Comunitaria , Filosofía en Enfermería , Enfermería Psiquiátrica , Femenino , Humanos , Entrevistas como Asunto , Japón , Masculino , Relaciones Enfermero-Paciente , Valores Sociales
13.
Open Biol ; 7(10)2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-29070610

RESUMEN

Current ageing theories are far from satisfactory because of the many determinants involved in ageing. The well-known rate-of-living theory assumes that the product (lifetime energy expenditure, LEE) of maximum lifespan (MLS) and mass-specific basal metabolic rate (msBMR) is approximately constant. Although this theory provides a significant inverse correlation between msBMR and MLS as a whole for mammals, it remains problematic for two reasons. First, several interspecies studies within respective orders (typically within rodents) have shown no inverse relationships between msBMR and MLS. Second, LEE values widely vary in mammals and birds. Here, to solve these two problems, we introduced a new quantity designated as mitochondrial (mt) lifetime energy output, mtLEO = MLS × mtMR, in place of LEE, by using the mt metabolic rate (mtMR) per mitochondrion. Thereby, we found that mtLEO values were distributed more narrowly than LEE ones, and strongly correlated with the four amino-acid variables (AAVs) of Ser, Thr and Cys contents and hydrophobicity of mtDNA-encoded membrane proteins (these variables were related to the stability of these proteins). Consequently, only these two mt items, mtMR and the AAVs, solved the above-mentioned problems in the rate-of-living theory, and thus extensively improved the correlation with MLS compared with that given by LEE.


Asunto(s)
Longevidad , Mitocondrias/fisiología , Envejecimiento , Algoritmos , Aminoácidos/química , Aminoácidos/metabolismo , Animales , Metabolismo Energético , Regulación de la Expresión Génica , Mamíferos , Potencial de la Membrana Mitocondrial , Proteínas de la Membrana/química , Proteínas de la Membrana/metabolismo , Modelos Biológicos , Análisis de Regresión
14.
Zoology (Jena) ; 121: 83-90, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-27939816

RESUMEN

Brown and green are the most commonly imitated colors in prey animals because both colors occur in a range of habitats. Many researchers have evaluated survival with respect to background color matching, but the pigment cell mechanisms underlying such coloration are not known. Dorsal coloration of East Asian Takydromus lizards has shifted from green to brown or from brown to green on multiple occasions during the diversification of the genus, thus giving us an opportunity to examine the cellular mechanisms of background color matching. Brown and green skin were found to differ with respect to the morphological characteristics of iridophores, with different thicknesses of the reflecting platelets and the cytoplasmic spacing between platelets, despite a shared vertical arrangement of pigment cells, i.e., xanthophores in the upper layer, iridophores in the middle layer, and melanophores at the bottom of the dermal layer, among the different Takydromus lizards. Iridophores of brown skin reflected longer wavelengths of light than those of green skin, which may be attributed to the thicker platelets and longer distances between platelets in brown skin. We discuss the potential role of genetic and intracellular mechanisms explaining the thickness and orientation of the light-reflecting platelets of iridophores in Takydromus lizards.


Asunto(s)
Cromatóforos/fisiología , Lagartos/fisiología , Pigmentación de la Piel/fisiología , Animales , Color , Pigmentos Biológicos , Especificidad de la Especie
15.
Mol Phylogenet Evol ; 117: 141-149, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-27940328

RESUMEN

The phylogeny mandala, which is a circular phylogeny with photos or drawings of species, is a suitable way to show visually how the biodiversity has developed in the course of evolution as clarified by the molecular phylogenetics. In this article, in order to demonstrate the recent progress of avian molecular phylogenetics, six phylogeny mandalas of various taxonomic groups of birds are presented with the lithographs of John Gould's folio bird books; i.e., (1) whole Aves, (2) Passeriformes, (3) Paradisaeidae in Corvoidea (Passeriformes), (4) Meliphagoidea (Passeriformes), (5) Trochili in Apodiformes, and (6) Galliformes.


Asunto(s)
Biodiversidad , Aves/clasificación , Aves/genética , Libros Ilustrados , Filogenia , Animales , Femenino , Galliformes/genética , Masculino , Passeriformes/genética , Fotograbar
16.
Curr Biol ; 27(1): 68-77, 2017 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-27989673

RESUMEN

The Palaeognathae comprise the flightless ratites and the volant tinamous, and together with the Neognathae constitute the extant members of class Aves. It is commonly believed that Palaeognathae originated in Gondwana since most of the living species are found in the Southern Hemisphere [1-3]. However, this hypothesis has been questioned because the fossil paleognaths are mostly from the Northern Hemisphere in their earliest time (Paleocene) and possessed many putative ancestral characters [4]. Uncertainties regarding the origin and evolution of Palaeognathae stem from the difficulty in estimating their divergence times [1, 2] and their remarkable morphological convergence. Here, we recovered nuclear genome fragments from extinct elephant birds, which enabled us to reconstruct a reliable phylogenomic time tree for the Palaeognathae. Based on the tree, we identified homoplasies in morphological traits of paleognaths and reconstructed their morphology-based phylogeny including fossil species without molecular data. In contrast to the prevailing theories, the fossil paleognaths from the Northern Hemisphere were placed as the basal lineages. Combined with our stable divergence time estimates that enabled a valid argument regarding the correlation with geological events, we propose a new evolutionary scenario that contradicts the traditional view. The ancestral Palaeognathae were volant, as estimated from their molecular evolutionary rates, and originated during the Late Cretaceous in the Northern Hemisphere. They migrated to the Southern Hemisphere and speciated explosively around the Cretaceous-Paleogene boundary. They then extended their distribution to the Gondwana-derived landmasses, such as New Zealand and Madagascar, by overseas dispersal. Gigantism subsequently occurred independently on each landmass.


Asunto(s)
Evolución Molecular , Extinción Biológica , Fósiles , Paleognatos/genética , Filogenia , Animales , Núcleo Celular/genética , Genoma , Genómica , Modelos Genéticos , Análisis de Secuencia de ADN/métodos
17.
Mol Phylogenet Evol ; 117: 168-178, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-27816710

RESUMEN

A circular phylogeny with photos or drawings of species is named a phylogeny mandala. This is one of the ways for illustrating the Tree of Life, and is suitable to show visually how the biodiversity has developed in the course of evolution as clarified by the molecular phylogenetics. To demonstrate the recent progress of molecular phylogenetics, six phylogeny mandalas for various taxonomic groups of life were presented; i.e., (1) Eukaryota, (2) Metazoa, (3) Hexapoda, (4) Tetrapoda, (5) Eutheria, and (6) Primates.


Asunto(s)
Biodiversidad , Libros Ilustrados , Evolución Molecular , Filogenia , Animales , Eucariontes/genética , Primates/genética
18.
Evol Dev ; 19(1): 29-39, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27882652

RESUMEN

The combination of body stripes and vivid blue tail color has independently evolved in different lizard families. To understand how and when lizards developed this coloration, we microscopically compared the embryonic development of pigment cells in two island populations of Plestiodon latiscutatus that exhibit either striped and blue tailed or inconspicuously striped and blue tailed juveniles, based on the newly determined 12 normal developmental stages of embryos from shortly after egg laying to just before hatching. We focus on the role of the melanophores in the body stripe and the role of iridophore morphotypes in the extent of blue tail coloration. The melanophore density in the black background region was higher in lizards with vivid stripes than in lizards with drab stripes. Iridophores started to fill the dermal space that was not yet occupied by melanophores, which resulted in a higher iridophore density in stripes than in the inter-stripe regions. We also discovered that iridophores with thin platelets reflecting blue structural coloration appeared at a specific region in the tail at stage 11. The position of the tail where iridophores emerged coincided with the boundary area separating anterior brown and green colored tail from posterior blue colored tail after hatching.


Asunto(s)
Lagartos/anatomía & histología , Animales , Evolución Biológica , Embrión no Mamífero/metabolismo , Femenino , Lagartos/embriología , Lagartos/genética , Melanóforos/metabolismo , Pigmentación , Cola (estructura animal)/anatomía & histología
19.
Genes Genet Syst ; 91(4): 209-215, 2017 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-27557976

RESUMEN

The giant rhinoceros beetles (Dynastini, Scarabaeidae, Coleoptera) are distributed in tropical and temperate regions in Asia, America and Africa. Recent molecular phylogenetic studies have revealed that the giant rhinoceros beetles can be divided into three clades representing Asia, America and Africa. Although a correlation between their evolution and the continental drift during the Pangean breakup was suggested, there is no accurate divergence time estimation among the three clades based on molecular data. Moreover, there is a long chronological gap between the timing of the Pangean breakup (Cretaceous: 110-148 Ma) and the emergence of the oldest fossil record (Oligocene: 33 Ma). In this study, we estimated their divergence times based on molecular data, using several combinations of fossil calibration sets, and obtained robust estimates. The inter-continental divergence events among the clades were estimated to have occurred about 99 Ma (Asian clade and others) and 78 Ma (American clade and African clade), both of which are after the Pangean breakup. These estimates suggest their inter-continental divergences occurred by overseas sweepstakes dispersal, rather than by vicariances of the population caused by the Pangean breakup.


Asunto(s)
Escarabajos/genética , Fósiles/anatomía & histología , Proteínas de Insectos/genética , Animales , Escarabajos/anatomía & histología , Evolución Molecular , Filogenia , Filogeografía , Análisis de Secuencia de ADN
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA