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1.
Int. j. morphol ; 37(2): 568-575, June 2019. tab
Artigo em Inglês | LILACS | ID: biblio-1002260

RESUMO

The aim of this study was to compare body composition (BC) and morphological symmetry differences among elite athletes (n = 132) in six martial arts (judo, karate, fencing, wrestling, taekwondo, kickboxing). Multivariate analysis of variances (MANOVA) was used to compare the following variables: absolute (FFM) and relative (FFMrel) value of fat free mass, percentage of fat mass (FMp), bone mass, protein mass, basal metabolic rate, absolute (TBW) and percentual (TBWp) value of total body water, segmental proportion of muscle mass, phase angle, and percent-age differences between the upper and lower limbs. MANOVA revealed significant differences in BC among the groups (λ = 0.01, F104, 256 = 10.01, p< 0.01, ηp2 = 0.67). No significant differences were observed for FMp, FFMrel, and TBWp (p>0.05). In all other BC variables, significant differences were detected (p<0.05). The comparison of paired differences between limbs revealed significantly greater fluid volume in the preferred arm compared to the non-preferred arm in karate and fencing athletes. Significant differences (p<0.05) in favour of the preferred leg in all combat athletes were detected. This study revealed morphological differences among practitioners of different martial arts and between paired limbs.


El objetivo de este estudio fue comparar la composición corporal (CC) y las diferencias de simetría morfológica entre atletas de élite (n = 132) en seis artes marciales (judo, karate, esgrima, lucha, taekwondo, kickboxing). Se utilizó el análisis multivariado de varianzas (MANOVA) para comparar las siguientes variables: valor absoluto (FFM) y relativo (FFMrel) de la masa libre de grasa, porcentaje de masa grasa (FMp), masa ósea, masa proteica, tasa metabólica basal, absoluto (TBW) y el valor porcentual (TBWp) de líquido corporal total, la proporción segmentaria de la masa muscular, el ángulo de fase y las diferencias porcentuales entre los miembros superiores e inferiores. MANOVA reveló diferencias significativas en BC entre los grupos (λ = 0,01, F104, 256 = 10,01, p <0,01, ηp2 = 0,67). No se observaron diferencias significativas para FMp, FFMrel y TBWp (p>0,05). En todas las demás variables de BC, se detectaron diferencias significativas (p<0,05). La comparación de las diferencias pareadas entre los miembros reveló un volumen de líquido significativamente mayor en el brazo dominante en comparación con el brazo no dominante en karate y atletas de esgrima. Se detectaron diferencias significativas (p<0,05) a favor de la pierna dominante en todos los atletas de combate. Este estudio reveló diferencias morfológicas entre los practicantes de diferentes artes marciales y entre las miembros emparejadas.


Assuntos
Humanos , Masculino , Composição Corporal , Artes Marciais , Extremidades/anatomia & histologia , Antropometria , Tecido Adiposo , Análise Multivariada
2.
Naturwissenschaften ; 106(7-8): 38, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31209559

RESUMO

Xiphosurida-crown group horseshoe crabs-are a group of morphologically conservative marine chelicerates (at least since the Jurassic). They represent an idealised example of evolutionary stasis. Unfortunately, body fossils of horseshoe crabs seldom preserve appendages and their associated features; thus, an important aspect of their morphology is absent in explorations of their conservative Bauplan. As such, fossil horseshoe crab appendages are rarely considered within a comparative framework: previous comparisons have focussed almost exclusively on extant taxa to the exclusion of extinct taxa. Here, we examine eight specimens of the xiphosurid Tachypleus syriacus (Woodward, 1879) from the Cenomanian (ca 100 Ma) Konservat-Lagerstätten of Lebanon, five of which preserve the cephalothoracic and thoracetronic appendages in exceptional detail. Comparing these appendages of T. syriacus with other fossil xiphosurids highlights the conserved nature of appendage construction across Xiphosurida, including examples of Austrolimulidae, Paleolimulidae, and Limulidae. Conversely, Belinuridae have more elongate cephalothoracic appendages relative to body length. Differences in appendage sizes are likely related to the freshwater and possible subaerial life modes of belinurids, contrasting with the primarily marine habits of other families. The morphological similarity of T. syriacus to extant members of the genus indicates that the conserved nature of the generic lineage can be extended to ecological adaptations, notably burrowing, swimming, possible diet, and sexual dimorphism.


Assuntos
Evolução Biológica , Fósseis/anatomia & histologia , Caranguejos Ferradura/anatomia & histologia , Caranguejos Ferradura/classificação , Adaptação Fisiológica , Animais , Ecossistema , Extremidades/anatomia & histologia , Filogenia , Especificidade da Espécie
3.
Arthropod Struct Dev ; 48: 71-82, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30639185

RESUMO

Pterothoracic structures of the minute ptiliid Nephanes titan were examined and described in detail. Effects of miniaturization and the phylogenetic and functional background are discussed. Apomorphies shared with Hydraenidae are the large metascutal shield, the fringe of setae along the posterior edge of the wings, and the fusion of the mesoventrite with the mesanepisternum. Autapomorphies of Ptiliidae are the highly modified feather-like wings, the strongly elongated alacristae, the loss of the mesotrochantin, the enlarged metathoracic pleural wing joint, and the simplification of the direct flight musculature. Most phylogenetically relevant features are linked with miniaturization, especially the modifications of the wings and skeleton, for instance the reduced wing membrane or the simplified metanotum without distinct notal wing processes. Ptiliids show flight characteristics that distinctly differ from what is known in other insects, such as an unusually high amplitude of beats of the elytra, and a unique trajectory of wing return movements, as well as the presence of upper and lower claps. A comparison of cross-sections of ptiliid principal flight muscles with those of larger staphyliniform beetles suggests that muscles of the tiniest beetles are relatively smaller. This may reflect the higher aerodynamic efficiency of ptiliid feather wings compared to the common membranous wings found in other groups.


Assuntos
Besouros/anatomia & histologia , Asas de Animais/anatomia & histologia , Animais , Tamanho Corporal , Besouros/fisiologia , Extremidades/anatomia & histologia , Voo Animal
4.
J Strength Cond Res ; 33(3): 597-605, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30640305

RESUMO

Fahs, CA, Blumkaitis, JC, and Rossow, LM. Factors related to average concentric velocity of four barbell exercises at various loads. J Strength Cond Res 33(3): 597-605, 2019-The resistance exercise load is the primarily determinant of the average concentric velocity (ACV) during a repetition. It is unknown whether individual factors such as training experience or anthropometrics also influence the ACV. Previous research has shown the ACV during the 1 repetition maximum (1RM) varies between exercises, but it is not clear whether ACV is different between exercises at various percentages of the 1RM. This information could provide practical guidelines for trainees using ACV to select training loads. Therefore, the purpose of this study was to determine whether training age, current training frequency, limb length, height, and relative strength are related to ACV at loads between 35 and 100% of the 1RM for the squat, bench press, deadlift, and overhead press. A secondary purpose was to compare the ACV values between the 4 lifts at each relative load. Fifty-one (18 women and 33 men) completed 2 testing sessions in which the squat, bench press, deadlift, and overhead press ACV were measured during a modified 1RM protocol. Average concentric velocity values were significantly different among the 4 lifts (p < 0.05) at all relative loads between 35 and 100% 1RM except for 55% 1RM (p = 0.112). Generally, compared at the same relative loads, the overhead press exhibited the greatest ACV followed by the squat, bench press, and deadlift (in order). In addition, relative strength level was inversely related to ACV at maximal loads (≥95% 1RM) for the squat, bench press, and deadlift while height was positively related to ACV at moderate loads (55% 1RM) for all lifts (p < 0.05). These results suggest that the load-velocity profile is unique for each of these exercises, and that velocity ranges used for exercise prescription should be specific to the exercise. A trainee's relative strength and height may be a primary influence on the ACV.


Assuntos
Contração Muscular , Treinamento de Resistência/métodos , Levantamento de Peso/fisiologia , Adolescente , Adulto , Fatores Etários , Estatura , Extremidades/anatomia & histologia , Feminino , Humanos , Masculino , Força Muscular , Adulto Jovem
5.
BMC Evol Biol ; 19(1): 16, 2019 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-30630409

RESUMO

BACKGROUND: The evolution of elongated body forms in tetrapods has a strong influence on the musculoskeletal system, including the reduction of pelvic and pectoral girdles, as well as the limbs. However, despite extensive research in this area it still remains unknown how muscles within and around bony girdles are affected by these reductions. Here we investigate this issue using fossorial amphisbaenian reptiles, or worm lizards, as a model system, which show substantial variation in the degree of reductions of girdles and limbs. Using iodine-based contrast-enhanced computed tomography (diceCT), we analyze the composition of the shoulder muscles of the main clades of Amphisbaenia and their outgroups relative to the pectoral skeleton. RESULTS: All investigated amphisbaenian taxa retain the full set of 17 shoulder muscles, independent of the degree of limb and girdle reductions, whereas in some cases muscles are fused to complexes or changed in morphology relative to the ancestral condition. Bipes is the only taxon that retains forelimbs and an almost complete pectoral girdle. All other amphisbaenian families show more variation concerning the completeness of the pectoral girdle having reduced or absent girdle elements. Rhineura, which undergoes the most severe bone reductions, differs from all other taxa in possessing elongated muscle strands instead of discrete shoulder muscles. In all investigated amphisbaenians, the shoulder muscle agglomerate is shortened and shifted anteriorly relative to the ancestral position as seen in the outgroups. CONCLUSIONS: Our results show that pectoral muscle anatomy does not necessarily correspond to the loss or reduction of bones, indicating a decoupling of the musculoskeletal system. Muscle attachment sites change from bones to non-skeletal areas, such as surrounding muscles, skin or connective tissue, whereas muscle origins themselves remain in the same region where the pectoral bones were ancestrally located. Our findings indicate a high degree of developmental autonomy within the musculoskeletal system, we predict that the observed evolutionary rearrangements of amphisbaenian shoulder muscles were driven by functional demands rather than by developmental constraints. Nevertheless, worm lizards display a spatial offset of both pectoral bones and muscles relative to the ancestral position, indicating severe developmental modifications of the amphisbaenian body axis.


Assuntos
Evolução Biológica , Extremidades/anatomia & histologia , Lagartos/anatomia & histologia , Músculos/anatomia & histologia , Sistema Musculoesquelético/anatomia & histologia , Animais , Osso e Ossos/anatomia & histologia , Membro Anterior/anatomia & histologia , Filogenia , Crânio/anatomia & histologia
6.
BMC Evol Biol ; 19(1): 3, 2019 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-30611195

RESUMO

BACKGROUND: The lake deposits of the informal Ruby Paper Shale unit, part of the Renova Formation of Montana, have yielded abundant plant fossils that document Late Eocene - Early Oligocene global cooling in western North America. A nearly complete small bird with feather impressions was recovered from this unit in in 1959, but has only been informally mentioned. RESULTS: Here we describe this fossil and identify it as a new species of Zygodactylus, a stem lineage passerine with a zygodactyl foot. The new taxon shows morphological traits that are convergent on crown Passeriformes, including an elongate hallux, reduced body size, and a comparative shortening of proximal limb elements. The fossil documents the persistence of this lineage into the earliest Oligocene (~ 33 Ma) in North America. It is the latest occurring North American species of a group that persists in Europe until the Miocene. CONCLUSIONS: Eocene-Oligocene global cooling is known to have significantly remodeled both Palearctic and Nearctic mammal faunas but its impact on related avifaunas has remained poorly understood. The geographic and temporal range expansion provided by the new taxon together with avian other taxa with limited fossil records suggests a similar pattern of retraction in North America followed by Europe.


Assuntos
Passeriformes/classificação , Filogenia , Animais , Tamanho Corporal , Extremidades/anatomia & histologia , Plumas/anatomia & histologia , Fósseis , Geografia , América do Norte , Crânio/anatomia & histologia , Especificidade da Espécie , Coluna Vertebral/anatomia & histologia , Fatores de Tempo
8.
Actas dermo-sifiliogr. (Ed. impr.) ; 109(6): 485-507, jul.-ago. 2018. ilus, tab
Artigo em Espanhol | IBECS | ID: ibc-175611

RESUMO

La dermatitis de contacto alérgica (DCA) es una enfermedad frecuente en la práctica clínica diaria, con una prevalencia que ha aumentado en los últimos años. Clínicamente se caracteriza por grados variables de eritema, vesiculación, descamación y liquenificación, signos que también están presentes en otros procesos eccematosos. Las pruebas epicutáneas constituyen la principal herramienta diagnóstica para confirmar una DCA, sin embargo, su correcta interpretación requiere de una correcta correlación entre la anamnesis (historial de exposición) y el examen físico. En este artículo se describen de forma práctica y didáctica los patrones clínicos más frecuentes de DCA dependiendo de su localización. El conocimiento de estos patrones no solo ayudará al clínico en el diagnóstico diferencial, sino que también le permitirá sospechar el posible alérgeno y su forma de aplicación


Allergic contact dermatitis (ACD) is a common disease in daily clinical practice, and its prevalence has increased in recent years. It is characterized clinically by varying degrees of erythema, vesiculation, flaking, and lichenification, though these signs can also be present in other eczematous diseases. Patch testing is the main diagnostic tool to confirm ACD, but its accurate interpretation requires correct correlation with the medical history (details of exposure) and physical examination. We provide a practical and instructive description of the most common clinical patters of ACD depending on the area affected. Knowledge of these patterns will not only help the clinician reach the diagnosis but will suggest possible allergens and forms of contact


Assuntos
Humanos , Dermatite de Contato/diagnóstico , Dermatopatias/diagnóstico , Pele/anatomia & histologia , Alérgenos/efeitos adversos , Diagnóstico Diferencial , Couro Cabeludo/anatomia & histologia , Face/anatomia & histologia , Pálpebras/anatomia & histologia , Pescoço/anatomia & histologia , Mãos/anatomia & histologia , Extremidades/anatomia & histologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-30017077

RESUMO

Recent studies have reported the reliability of MALDI-TOF MS for arthropod identification, including fresh or alcohol-preserved ticks based on leg-derived mass spectra. The aim of this study was to evaluate the performance of MALDI-TOF MS for the identification of alcohol-preserved Algerian ticks collected from different domestic and wild hosts. Secondly, we conducted a molecular survey to detect the presence of bacterial DNA in all ticks that were previously subjected to MALDI-TOF MS. A total of 2635 ixodid and 1401 argasid ticks belonging to 9 distinct species were collected in nine different regions of northeastern Algeria. The legs of 230 specimens were subjected to MALDI-TOF MS assays. Spectral analysis revealed intra-species similarity and inter-species specificity for the MS spectra, which was consistent with the morphological identification. Blind tests against the in-lab database revealed that 93.48% of the tested specimens were correctly identified. The accuracy of the morphological and MALDI-TOF MS identifications was validated by sequencing the 12S ribosomal RNA gene (rRNA) for 33 specimens and all the ticks were correctly identified. The quantitative PCR screening showed that for 219 tested ticks, 15 were positive for Rickettsia spp., 8 for Borrelia spp. and 17 for Anaplasmataceae. The PCR tests were negative for Coxiella burnetii and Bartonella spp. This study supports MALDI-TOF MS being a reliable tool for the identification of arthropods and brings new data that sheds light on tick species diversity and tick-borne diseases in Algeria.


Assuntos
Anaplasmataceae/genética , Borrelia/genética , DNA Bacteriano/genética , Extremidades/anatomia & histologia , Rickettsia/genética , Carrapatos/classificação , Argélia/epidemiologia , Anaplasmataceae/classificação , Anaplasmataceae/isolamento & purificação , Animais , Animais Selvagens/parasitologia , Bartonella , Borrelia/classificação , Borrelia/isolamento & purificação , Coxiella burnetii , Filogenia , Reação em Cadeia da Polimerase/métodos , Rickettsia/classificação , Rickettsia/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Infestações por Carrapato/epidemiologia , Carrapatos/anatomia & histologia , Carrapatos/microbiologia
10.
BMC Evol Biol ; 18(1): 73, 2018 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-29783957

RESUMO

BACKGROUND: The morphological and functional evolution of appendages has played a key role in the diversification of arthropods. While the ancestral arthropod appendage is held to be polyramous, terrestriality is associated with the reduction or loss of appendage rami, which may obscure the homology of different appendage derivatives. Proxies for appendage homology have included surveys of cross-reactive antibodies for wing markers like Nubbin/PDM, which have suggested that the abdominal appendages of arachnids (e.g., book lungs, tracheal tubules) are derived from ancestral gills (epipods). RESULTS: Here, we discovered a rare case of inferred homeosis in a scorpion in which the bilobed genital opercula and the pectines are transformed to walking legs, and an abnormal sternite shows a book lung close to an everted structure comparable to the morphology of some Palaeozoic scorpion fossils. CONCLUSIONS: The observed morphology is consistent with abnormal expression of homeotic genes during embryonic development. The phenotype of this abnormal specimen suggests that the genital opercula, the pectines, and parts of the book lung may be derived from the telopodite of abdominal appendages rather than from epipods. This interpretation contradicts the "ancestral gill" hypothesis but reconciles features of the Palaeozoic scorpion fossil record with the embryology of modern scorpions.


Assuntos
Evolução Biológica , Genes Homeobox , Brânquias/anatomia & histologia , Escorpiões/anatomia & histologia , Escorpiões/genética , Animais , Extremidades/anatomia & histologia , Fósseis , Fenótipo , Escorpiões/embriologia
11.
Ann Anat ; 218: 205-212, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29730469

RESUMO

INTRODUCTION: Information on microscopic anatomy of equine skin is sparse. In horses, limb wounds often become chronic and/or non-healing whereas body wounds heal normally. These dissimilarities in healing patterns might be a product of different phenotypic characteristics of body and limb skin. The objective of this study was to investigate microscopic anatomy, epidermal thickness, keratinocyte proliferation and differentiation as well as the presence of mast cells in normal equine skin of body and limb. MATERIALS AND METHODS: The study involved body and limb skin biopsies from six horses. Histological characteristics of the epidermis were assessed and epithelial thickness measured. Immunohistochemistry was performed to investigate epidermal differentiation patterns of cytokeratin (CK) 10, CK14, CK16, loricrin, and peroxisome proliferator-activated receptor alpha (PPAR-α), epidermal proliferation (Ki-67 immunostaining), and mast cells distribution in the skin. RESULTS: The epidermis was significantly thicker in the limb skin compared to body skin (p<0.01). Epidermal proliferation and CK distribution did not show differences in the two anatomical areas. Loricrin presence was focally found in the spinous layer in four out of six limb skin samples but not in body skin samples. Tryptase positive mast cells were detected in the dermis and their density (cell/mm2) was not different between body and limb. DISCUSSION AND CONCLUSION: Here we report for the first time about the normal distribution of CK10, CK14, CK16, PPAR-α, and loricrin in equine limb and body skin as well as about epidermal proliferation rate and mast cell count. It will be relevant to investigate the distribution of the investigated epithelial differentiation markers and the role of mast cells during equine wound healing and/or other skin diseases.


Assuntos
Cavalos/anatomia & histologia , Pele/anatomia & histologia , Animais , Diferenciação Celular , Proliferação de Células , Derme/citologia , Células Epidérmicas , Epiderme/anatomia & histologia , Epiderme/ultraestrutura , Extremidades/anatomia & histologia , Imuno-Histoquímica , Queratinócitos/ultraestrutura , Queratinas/metabolismo , Masculino , Mastócitos/ultraestrutura , Proteínas de Membrana/metabolismo , Pele/citologia , Pele/ultraestrutura
12.
Semin Musculoskelet Radiol ; 22(3): 275-285, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29791956

RESUMO

Accessory muscles and variations are not uncommon at the upper and lower extremity. They are often overlooked because they are asymptomatic and present as incidental findings on imaging. However, they may present as a soft tissue swelling, thereby mimicking soft tissue tumors. Other symptoms are attributed to impingement on neurovascular structures and to exercise-related pain. Thorough knowledge of the anatomy, systematic imaging analysis, and the awareness of it are the clues to correct identification. On ultrasound, accessory muscles have a similar echotexture as other muscles, whereas the signal intensity on magnetic resonance imaging (MRI) is similar to muscle. Because of the intrinsic contrast with the adjacent intermuscular fat, accessory muscles are best depicted on MRI without fat suppression. This article provides a short overview of the anatomy of most prevalent accessory muscles of the upper and lower limb and its potential pathogenic nature.


Assuntos
Diagnóstico por Imagem , Extremidades/anatomia & histologia , Músculo Esquelético/anormalidades , Músculo Esquelético/anatomia & histologia , Variação Anatômica , Humanos
13.
Ticks Tick Borne Dis ; 9(4): 778-780, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29525551

RESUMO

Morphological anomalies have been reported in the blacklegged tick, Ixodes scapularis (Acari: Ixodidae), from the northeastern and upper Midwestern United States, complicating identification of this important vector of human pathogens. Here, we report a case of a local morphological anomaly in I. scapularis, parasitizing a human living in Connecticut. We used a dichotomous morphological key, high-resolution and scanning electron microscopy images, as well as DNA sequencing for identification. The specimen was identified as an adult female I. scapularis with the left leg II split at the trochanter, resulting in two complete legs from the femur to pretarsus giving the appearance of five legs on the left side versus four on the right side. Here we discuss recent reports of morphological anomalies in I. scapularis, and highlight the need for further studies of teratology in this important tick species and its potential implications.


Assuntos
Extremidades/anatomia & histologia , Ixodes/anatomia & histologia , Animais , Feminino , Ixodes/genética , Ixodes/ultraestrutura , Locomoção , Microscopia Eletrônica de Varredura , Meio-Oeste dos Estados Unidos/epidemiologia , New England/epidemiologia , Análise de Sequência de DNA , Infestações por Carrapato/epidemiologia
14.
PLoS One ; 13(2): e0191400, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29444161

RESUMO

Limulus polyphemus, an archetypal chelicerate taxon, has interested both biological and paleontological researchers due to its unique suite of anatomical features and as a useful modern analogue for fossil arthropod groups. To assist the study and documentation of this iconic taxon, we present a 3D atlas on the appendage musculature, with specific focus on the muscles of the cephalothoracic appendages. As L. polyphemus appendage musculature has been the focus of extensive study, depicting the muscles in 3D will facilitate a more complete understanding thereof for future researchers. A large museum specimen was CT scanned to illustrate the major exoskeletal features of L. polyphemus. Micro-CT scans of iodine-stained appendages from fresh, non-museum specimens were digitally dissected to interactively depict appendage sections and muscles. This study has revealed the presence of two new muscles: one within the pushing leg, located dorsally relative to all other patella muscles, and the other within the male pedipalp, located in the modified tibiotarsus. This atlas increases accessibility to important internal and external morphological features of L. polyphemus and reduces the need for destructive fresh tissue dissection of specimens. Scanning, digitally dissecting, and documenting taxa in 3D is a pivotal step towards creating permanent digital records of life on Earth.


Assuntos
Fósseis/diagnóstico por imagem , Caranguejos Ferradura/anatomia & histologia , Animais , Extremidades/anatomia & histologia , Fósseis/anatomia & histologia , Caranguejos Ferradura/fisiologia , Imagem Tridimensional , Músculos/anatomia & histologia , Músculos/diagnóstico por imagem , Paleontologia/métodos , Tomógrafos Computadorizados
15.
Nat Commun ; 9(1): 470, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29391458

RESUMO

Euarthropods owe their evolutionary and ecological success to the morphological plasticity of their appendages. Although this variability is partly expressed in the specialization of the protopodite for a feeding function in the post-deutocerebral limbs, the origin of the former structure among Cambrian representatives remains uncertain. Here, we describe Alacaris mirabilis gen. et sp. nov. from the early Cambrian Xiaoshiba Lagerstätte in China, which reveals the proximal organization of fuxianhuiid appendages in exceptional detail. Proximally, the post-deutocerebral limbs possess an antero-posteriorly compressed protopodite with robust spines. The protopodite is attached to an endopod with more than a dozen podomeres, and an oval flap-shaped exopod. The gnathal edges of the protopodites form an axial food groove along the ventral side of the body, indicating a predatory/scavenging autecology. A cladistic analysis indicates that the fuxianhuiid protopodite represents the phylogenetically earliest occurrence of substantial proximal differentiation within stem-group Euarthropoda illuminating the origin of gnathobasic feeding.


Assuntos
Artrópodes/anatomia & histologia , Evolução Biológica , Extremidades/anatomia & histologia , Animais , China , Fósseis , Filogenia
16.
Arthropod Struct Dev ; 47(1): 12-24, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29221679

RESUMO

Gnathobasic spines are located on the protopodal segments of the appendages of various euarthropod taxa, notably chelicerates. Although they are used to crush shells and masticate soft food items, the microstructure of these spines are relatively poorly known in both extant and extinct forms. Here we compare the gnathobasic spine microstructures of the Silurian eurypterid Eurypterus tetragonophthalmus from Estonia and the Cambrian artiopodan Sidneyiainexpectans from Canada with those of the Recent xiphosuran chelicerate Limulus polyphemus to infer potential variations in functional morphology through time. The thickened fibrous exocuticle in L. polyphemus spine tips enables effective prey mastication and shell crushing, while also reducing pressure on nerve endings that fill the spine cavities. The spine cuticle of E. tetragonophthalmus has a laminate structure and lacks the fibrous layers seen in L. polyphemus spines, suggesting that E. tetragonophthalmus may not have been capable of crushing thick shells, but a durophagous habit cannot be precluded. Conversely, the cuticle of S. inexpectans spines has a similar fibrous microstructure to L. polyphemus, suggesting that S. inexpectans was a competent shell crusher. This conclusion is consistent with specimens showing preserved gut contents containing various shelly fragments. The shape and arrangement of the gnathobasic spines is similar for both L. polyphemus and S. inexpectans, with stouter spines in the posterior cephalothoracic or trunk appendages, respectively. This differentiation indicates that crushing occurs posteriorly, while the gnathobases on anterior appendages continue mastication and push food towards and into the mouth. The results of recent phylogenetic analyses that considered both modern and fossil euarthropod clades show that xiphosurans and eurypterids are united as crown-group euchelicerates, with S. inexpectans placed within more basal artiopodan clades. These relationships suggest that gnathobases with thickened fibrous exocuticle, if not homoplasious, may be plesiomorphic for chelicerates and deeper relatives within Arachnomorpha. This study shows that the gnathobasic spine microstructure best adapted for durophagy has remained remarkably constant since the Cambrian.


Assuntos
Artrópodes/ultraestrutura , Evolução Biológica , Fósseis/ultraestrutura , Animais , Extremidades/anatomia & histologia , Caranguejos Ferradura/ultraestrutura , Microscopia Eletrônica de Varredura
17.
Zoology (Jena) ; 126: 1-10, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29157879

RESUMO

The dactyl plunger of Alpheus sp. was found to be a layered composite, with mineral-rich outer and inner layers and a chitin-rich middle layer of high porosity. The chitin-rich middle layer is itself composed of several porous chitin laminae. Modelling heat conduction through the plunger cross-section revealed that the chitin-rich layer is able to insulate heat and retard its progress through the material. Heat accumulates in the plunger after a series of successive snaps and as such, its thermally resistant design can be considered most useful under the conditions of successive snapping. The plunger has a concurrent mechanical damage-tolerant design with biogenic mineral layers, viscous (chitin-mineral) interfaces, energy-dissipating porous chitin, and sidewalls composed of ordered, layered aragonite. The snapping shrimp plunger has a design that may protect it and internal soft tissues from thermomechanical damage during plunger-socket compression prior to cavitation bubble release.


Assuntos
Decápodes (Crustáceos)/anatomia & histologia , Animais , Fenômenos Biomecânicos/fisiologia , Decápodes (Crustáceos)/genética , Decápodes (Crustáceos)/fisiologia , Decápodes (Crustáceos)/ultraestrutura , Extremidades/anatomia & histologia , Extremidades/fisiologia , Temperatura Alta , Microscopia Eletrônica de Varredura
18.
J Morphol ; 279(1): 109-131, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29044744

RESUMO

In arachnids, pedipalps are highly variable appendages that may be used in feeding, courtship, defense, and agonistic encounters. In cosmetid harvestmen, adults have pedipalps that feature flattened femora, spoon-shaped tibiae, and robust tarsal claws. In contrast, the pedipalps of nymphs are elongate with cylindrical podomeres and are adorned with delicate pretarsi. In this study, we used scanning electron microscopy to examine the distribution of cuticular structures (e.g., sensilla chaetica, pores) on the elements of the pedipalps of adults and nymphs of three species of cosmetid harvestmen. Our results indicate that there is considerable ontogenetic variation in the morphology of the trochanter, femur, patella, tibia, and tarsus. The pretarsus of the nymph has a ventral patch of setae that is absent from the adult tarsal claw. We observed this structure on all three cosmetid species as well as on the pedipalps of an additional seven morphospecies of nymphs collected in Belize and Costa Rica. This structure may represent a previously unrecognized autapomorphy for Cosmetidae. Examinations of the pedipalps of antepenultimate nymphs of additional gonyleptoidean harvestmen representing the families Ampycidae, Cranaidae, Manaosbiidae, and Stygnidae revealed the occurrence of unusual, plumose tarsal setae, but no setal patches on the tarsal claw.


Assuntos
Aracnídeos/anatomia & histologia , Órgãos dos Sentidos/anatomia & histologia , Animais , Aracnídeos/ultraestrutura , Belize , Osso e Ossos/anatomia & histologia , Osso e Ossos/ultraestrutura , Extremidades/anatomia & histologia , Feminino , Larva/anatomia & histologia , Larva/ultraestrutura , Masculino , Tamanho do Órgão , Patela/ultraestrutura , Órgãos dos Sentidos/ultraestrutura , Sensilas/anatomia & histologia , Sensilas/ultraestrutura , Caracteres Sexuais
19.
PLoS One ; 12(11): e0188752, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29176856

RESUMO

Prenatal sex hormones exert organizational effects. It has been suggested that prenatal sex hormones affect adult morphological parameters, such as the finger length. Especially the second-to-fourth finger length (2D:4D) ratio has been implicated to be modified when exposed to higher androgen levels in utero. Here we show in a mouse model that experimental manipulation of the prenatal androgen level, by blocking the androgen receptor with flutamide or activating the androgen receptor with dihydrotestosterone (DHT), leads to changes in the length of the fingers of all paws in males and females. In addition to that, also total paw length and the 2D:4D ratio was affected. In males treated with DHT, the 2D:4D ratio was increased, while flutamide-treatment in females led to a reduced 2D:4D ratio. We also measured other parameters, such as head size, body length and tail length and demonstrate that body morphology is affected by prenatal androgen exposure with more prominent effects in females. Another factor that is thought to be influenced by early androgens is handedness. We tested mice for handedness, but did not find a significant effect of the prenatal treatment. These findings demonstrate that prenatal androgen activity is involved in the development of body morphology and might be a useful marker for prenatal androgen exposure.


Assuntos
Extremidades/anatomia & histologia , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Receptores Androgênicos/metabolismo , Animais , Tamanho Corporal , Di-Hidrotestosterona/farmacologia , Feminino , Flutamida/farmacologia , Lateralidade Funcional/efeitos dos fármacos , Hormônios Esteroides Gonadais/metabolismo , Masculino , Camundongos , Gravidez
20.
Proc Natl Acad Sci U S A ; 114(47): 12378-12383, 2017 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-29109262

RESUMO

X-ray computed tomography (CT) is a powerful noninvasive technique for investigating the inner structure of objects and organisms. However, the resolution of laboratory CT systems is typically limited to the micrometer range. In this paper, we present a table-top nanoCT system in conjunction with standard processing tools that is able to routinely reach resolutions down to 100 nm without using X-ray optics. We demonstrate its potential for biological investigations by imaging a walking appendage of Euperipatoides rowelli, a representative of Onychophora-an invertebrate group pivotal for understanding animal evolution. Comparative analyses proved that the nanoCT can depict the external morphology of the limb with an image quality similar to scanning electron microscopy, while simultaneously visualizing internal muscular structures at higher resolutions than confocal laser scanning microscopy. The obtained nanoCT data revealed hitherto unknown aspects of the onychophoran limb musculature, enabling the 3D reconstruction of individual muscle fibers, which was previously impossible using any laboratory-based imaging technique.


Assuntos
Imagem Tridimensional/métodos , Invertebrados/anatomia & histologia , Músculos/anatomia & histologia , Nanotecnologia/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Extremidades/anatomia & histologia , Extremidades/diagnóstico por imagem , Imagem Tridimensional/instrumentação , Microscopia Confocal/métodos , Microscopia Eletrônica de Varredura/métodos , Músculos/diagnóstico por imagem , Nanotecnologia/instrumentação , Tomografia Computadorizada por Raios X/instrumentação
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