RESUMEN
The advent of scanning electron microscopy has facilitated our understanding of the biology in relation to surface microstructure of many invertebrates. In recent years, interest in biomimetics and bio-inspired materials has further propelled the search for novel microstructures from natural surfaces. As this search widens in diversity to nurture deeper understanding of form and function, the need often arises to examine rare specimens. Unfortunately, most methods for characterization of the microtopography of natural surfaces are sacrificial, and as such, place limiting constraints on research progress in situations where only a few rare specimens are known, such as the rich resources lodged in natural history museum collections. In this paper, we introduce the use of optical coherence tomography (OCT) as a noninvasive tool for bioimaging surface microtopography of crab shells. The technique enables the capture of microstructures down to micron level using low coherence near-infrared light source. OCT has allowed surface microtopography imaging on crab shells to be carried out rapidly and in a nondestructive manner, compared to the scanning electron microscope technique. The microtopography of four preserved crab specimens from Acanthodromia margarita, Ranina ranina, Conchoecetes intermedius and Dromia dormia imaged using OCT were similar to images obtained from scanning electron microscope, showing that OCT imaging retains the overall morphological form during the scanning process. By comparing the physical lengths of the spinal structures from images obtained from OCT and scanning electron microscope, the results showed that dimensional integrity of the images captured from OCT was also maintained.
Asunto(s)
Exoesqueleto/ultraestructura , Decápodos/ultraestructura , Tomografía de Coherencia Óptica/métodos , Animales , Tomografía con Microscopio Electrónico/métodos , Microscopía Electrónica de Rastreo/métodosRESUMEN
Over the past several decades molecular tools have shown an enormous potential to aid in the clarification of species boundaries in the marine realm, particularly in morphologically simple groups. In this paper we report a case of cryptic speciation in an allegedly cosmopolitan and ecologically important species-the excavating sponge Cliona celata (Clionaidae, Hadromerida). In the Northeast Atlantic and Mediterranean C. celata displays a discontinuous distribution of its putative growth stages (boring, encrusting, and massive) leading us to investigate its specific status. Phylogenetic reconstructions of mitochondrial (COI, Atp8) and nuclear (28S) gene fragments revealed levels of genetic diversity and divergence compatible with interspecific relationships. We therefore demonstrate C. celata as constituting a species complex comprised of at least four morphologically indistinct species, each showing a far more restricted distribution: two species on the Atlantic European coasts and two on the Mediterranean and adjacent Atlantic coasts (Macaronesian islands). Our results provide further confirmation that the different morphotypes do indeed constitute either growth stages or ecologically adapted phenotypes as boring and massive forms were found in two of the four uncovered species. We additionally provide an overview of the cases of cryptic speciation which have been reported to date within the Porifera, and highlight how taxonomic crypsis may confound scientific interpretation and hamper biotechnological advancement. Our work together with previous studies suggests that overconservative systematic traditions but also morphological stasis have led to genetic complexity going undetected and that a DNA-assisted taxonomy may play a key role in uncovering the hidden diversity in this taxonomic group.
Asunto(s)
Evolución Molecular , Especiación Genética , Filogenia , Poríferos/genética , Animales , Océano Atlántico , Núcleo Celular/genética , ADN Mitocondrial/genética , Variación Genética , Geografía , Mar Mediterráneo , Poríferos/clasificación , Análisis de Secuencia de ADNRESUMEN
Demosponge higher-level systematics is currently a subject of major changes due to the simplicity and paucity of complex morphological characters. Still, sponge classification is primarily based on morphological features. The systematics of the demosponge order Agelasida has been exceptionally problematic in the past. Here, we present the first molecular phylogenetic analysis based on three partially independent genes in demosponges in combination with a comprehensive search for biochemical synapomorphies to indicate their phylogenetic relationships. We show how sponges with fundamentally different skeletons can be in fact closely related and discuss examples of the misleading nature of morphological systematics in sponges.
Asunto(s)
Complejo IV de Transporte de Electrones/genética , Factor 1 de Elongación Peptídica/genética , Poríferos/anatomía & histología , Poríferos/clasificación , ARN Ribosómico 28S/genética , Animales , Biomarcadores/análisis , ADN Ribosómico/genética , Filogenia , Poríferos/genéticaRESUMEN
Three adult patients with leukemia and a patient with cutaneous melanoma were treated with a variety of therapeutic agents administered systemically. Three of these patients received either cytosine arabinoside or thio-TEPA, by intrathecal injection and radiotherapy to the cranium or spine. Three patients developed progressive motor and sensory deficits and the fourth became confused and disoriented. These symptoms were chronologically related to the time when chemotherapy was begun. Death occurred 11/2, 2, 5 and 7 months, respectively, after the beginning of neurologic deficit. The spinal white matter showed vacuolation, myelin disintegration, axonal swelling, fibrillary gliosis, and infiltration by macrophages. Vesicular disintegration of the myelin lamellae seems to be the earliest lesion affecting both central and peripheral myelin. Gliosis and macrophages were visible only in the two patients who survived at least five months from the time of the neurologic deficit.
Asunto(s)
Encéfalo/efectos de los fármacos , Citarabina/efectos adversos , Médula Espinal/efectos de los fármacos , Tiotepa/efectos adversos , Adulto , Anciano , Axones/patología , Axones/ultraestructura , Citarabina/administración & dosificación , Citoesqueleto/ultraestructura , Femenino , Humanos , Inyecciones Espinales , Leucemia/tratamiento farmacológico , Masculino , Melanoma/tratamiento farmacológico , Persona de Mediana Edad , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/ultraestructura , Neoplasias Cutáneas/tratamiento farmacológico , Médula Espinal/patologíaRESUMEN
Durante los primeros seis anos y medio de funcionamiento del Instituto Neurologico de Colombia, se atendieron un total de 404 pacientes con algun tipo de tumor cerebral. La frecuencia de estas lesiones fue mayor en la 5a. decada, con predominancia ligera en el sexo masculino. En un 6,4%, de los casos, la sintomatologia se inicio subitamente y la escanografia cerebral demostro ser el mejor examen paraclinico como metodo diagnostico.Los gliomas y meningiomas fueron los tumores mas frecuentes y en los ninos los infratentoriales alcanzaron la mayor incidencia. La mortalidad hospitalaria fue de 9,5% y la mayoria de los pacientes se han podido reintegrar a su actividad familiar o laboral
Asunto(s)
Neoplasias EncefálicasRESUMEN
Los autores presentan los detalles de la tecnica de la IFI para el diagnostico de la cisticercosis y las primeras experiencias alcanzadas en 15 examenes realizados en el Laboratorio del Instituto Neurologico de Colombia.De siete pacientes con cisticercosis seis mostraron reacciones positivas en diluciones mayores del 1.40. En un caso con calcificaciones la IFI fue considerada falso negativo.En siete pacientes con enfermedades neurologicas diversas la IFI fue negativa con diluciones menores de 1:20. Se considero falso positivo el caso de un hombre de 90 anos con VDRL reactivo al 1:2 y una IFI positiva al 1:80