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‣ Histological study of the dynamics in epidermis regeneration of the carp tail fin (Cyprinus carpio, Linnaeus, 1758)

Böckelmann, P. K.; Ochandio, B. S.; Bechara, I. J.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: 217-223
Português
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); As nadadeiras dos teleósteos, quando parcialmente amputadas, sofrem um processo de regeneração chamado de regeneração epimórfica, caracterizado pelas seguintes fases: cicatrização, a partir da formação de uma capa epidermal multiestratificada, formação de uma massa de células mesenquimais multipotentes chamada blastema, diferenciação dessas células, síntese e deposição de matriz extracelular, crescimento e restauração morfológica. A epiderme tem papel fundamental no processo regenerativo das nadadeiras dos peixes, uma vez que a velocidade de cicatrização dessa estrutura leva a um processo regenerativo mais rápido e, também, age como uma defesa contra o ambiente externo. Assim, devido à rápida regeneração que a epiderme apresenta, tivemos como objetivo, neste trabalho, estudar a histologia da dinâmica regenerativa da epiderme das nadadeiras caudais da carpa (Cyprinus carpio) ao microscópio de luz e eletrônico de transmissão. A regeneração da epiderme tem início já nas primeiras horas após a amputação das nadadeiras e continua durante todo o processo regenerativo. Após 24 horas, uma capa epidermal apical é estabelecida. Prolongamentos citoplasmáticos e junções intercelulares são observados e as células da camada basal da epiderme passam da forma cúbica para a cilíndrica...

‣ Modelo de pele humana (derme + epiderme) reconstruida in vitro; Model of human skin (dermis + epidermis) reconstructed in vitro

Luis Ricardo Martinhão Souto
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/02/2005 Português
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A obtenção de uma pele humana que apresente derme e epiderme, reconstruída a partir de células isoladas de pacientes, possibilita a realização de enxertos autólogos de pele reconstruída em laboratório (in vitro) em pacientes com áreas doadoras escassas além de permitir ensaios com substâncias químicas e drogas in vitro e não mais in vivo. A partir da cultura de fibroblastos humanos, é possível obter um número suficiente de células que podem ser injetadas em uma matriz de colágeno bovino tipo I que, mantida imersa em meio de cultura, específico para fibroblastos, permite a formação de uma derme humana reconstruída in vitro. Sobre essa derme, através de cultura de queratinócitos e melanócitos humanos, forma-se uma epiderme diferenciada levando à formação de uma pele humana reconstruída in vitro, constituída de derme e epiderme associadas. Essa pele humana formada é, histologicamente, semelhante à pele humana in vivo. Na derme, identifica-se o tecido colágeno, com suas células, e a matriz extracelular organizados paralelamente à epiderme. Esta se desenvolve em várias camadas. Não há distinção entre derme e epiderme no experimento controle, onde não foi utilizado o colágeno bovino tipo I; The technique to obtain human skin presenting dermis and epidermis reconstructed from cells isolated from patients allows the performance of autologous grafts of skin reconstructed in laboratory (in vitro) on patients with scarce donor sites...

‣ Morphometry of the epidermis of an invasive megascoelecid earthworm (Amynthas gracilis, Kinberg 1867) inhabiting actively volcanic soils in the Azores archipelago

Cunha, Luís; Campos, Itxaso; Montiel, Rafael; Rodrigues, Armindo; Morgan, Andrew
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /01/2011 Português
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Copyright (c) 2010 Elsevier Inc. All rights reserved.; For the first time, the structure, dimensions, and composition of the epidermis of an invasive earthworm species that has successfully colonized hostile conditions in actively volcanic soil on Sao Miguel (Azores) have been measured. Metal concentrations in actively volcanic (Furnas) and volcanically inactive(Fajã) soils were similar; however, Furnas soil was characterised by elevated temperature (10 1C differential), relative hypoxia, extremely high CO2 tension, and accompanying acidity. The epidermis of earthworm’s resident at Fajã was approximately twice the thickness of the epidermis of conspecifics resident in Furnas soil. Reference worms transferred to Furnas soil for 14 days experienced an epidermal thinning of approximately 51%. In comparison, when Furnas earthworms were transferred to mesocosms at the relatively benign Fajã site, their epidermal thickness increased by approximately 21%over 14 days. Earthworms resident in Furnas soil had higher goblet cell counts than the residents of volcanically inactive soil on a neighbouring island (S.Maria). Transferring worms from S.Maria to mesocosmsat Furnas induced a significant increase in goblet cell counts. Clearly, the active volcanic environment at Furnas poses a multifactorial stress challenge to the epigeic A. gracilis colonizer.

‣ Model of human epidermis reconstructed in vitro with keratinocytes and melanocytes on dead de-epidermized human dermis

Rehder,Jussara; Souto,Luís Ricardo Martinhão; Issa,Cláudia Maria Bernardino Magro; Puzzi,Maria Beatriz
Fonte: Associação Paulista de Medicina - APM Publicador: Associação Paulista de Medicina - APM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2004 Português
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CONTEXT: Recent progress in the field of epithelial culture techniques has allowed the development of culture systems in which the reconstructed epidermis presents characteristics of morphological differentiation similar to those seen in vivo. Human epidermis reconstructed in vitro may be used as the best alternative for the in vitro testing of the toxicology and efficiency of products for topical use, as well as in the treatment of skin burns and chronic skin ulcers. OBJECTIVE: To demonstrate a method for obtaining human epidermis reconstructed in vitro, using keratinocytes and melanocytes cultivated on dead de-epidermized human dermis. TYPE OF STUDY: Experimental/laboratory. SETTING: Skin Cell Culture Laboratory of the Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil. PROCEDURE: Human keratinocytes and melanocytes cultured in vitro were grown on a biological matrix (dead de-epidermized human dermis) and the system was kept at an air-liquid interface, in a suitable culturing medium, until a stratified human epidermis was formed, maintaining the histological characteristics of the epidermis in vivo. RESULTS: It was histologically demonstrated that it is possible to reproduce a differentiated epidermis through keratinocytes and melanocytes cultured on dead de-epidermized human dermis...

‣ Histological study of the dynamics in epidermis regeneration of the carp tail fin (Cyprinus carpio, Linnaeus, 1758)

Böckelmann,PK.; Ochandio,BS.; Bechara,IJ.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2010 Português
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Teleostean fins when partially amputated suffer a regenerative process called epimorphic regeneration, characterized by the following stages: healing, based on the formation of a multistratified epidermal layer, the formation of a mass of pluripotent cells known as blastema, the differentiation of these cells, the synthesis and disposition of the extracellular matrix, morphological growth and restoration. The epidermis has a fundamental role in the regenerative process of fish fins, as the healing time of this structure leads it to a faster regenerative process and it also works as a defense against the external environment. In this sense, due to the fast regeneration shown by the epidermis, the aim of this paper is to study the histology of the regenerative dynamics of the carp fin tail (Cyprinus carpio), under the light and transmission electron microscope. Epidermic regeneration begins right in the first hours after the fin amputation and it continues throughout the regenerative process. After 24 hours, an apical epidermal cap is established. Cytoplasmatic prolongations and intercellular junctions are observed and the cells of the basal layer of the epidermis change from the cubic form to the cylindrical, due to the development of the cytoplasmatic organelles responsible for the synthesis of the basal membrane...

‣ Increased concentrations of nonesterified arachidonic acid, 12L-hydroxy-5,8,10,14-eicosatetraenoic acid, prostaglandin E2, and prostaglandin F2alpha in epidermis of psoriasis.

Hammarström, S; Hamberg, M; Samuelsson, B; Duell, E A; Stawiski, M; Voorhees, J J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1975 Português
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Lesional epidermis of psoriasis has a probable reduction in the cyclic AMP/cyclic GMP ratio. This altered ratio may in part be responsible for the characteristic glycogen storage, rapid cell proliferation, and reduced differentiation in lesional epidermis. The concentrations of prostaglandins E2 and F2alpha, free arachidonic acid, and 12L-hydroxy-5,8,10,14-eicosatetrawnoic acid in specimens of uninvolved and involved epidermis of psoriasis were measured with deuterium-labeled carriers and multiple ion analysis. Snap frozen specimens contained: 1.4 +/- 0.4 mug/g (wet weight) of arachidonic acid in uninvolved in contrast to 36.3 +/- 16.7 mug/g in involved epidermis (P = 0.015); less than 0.05 +/- 0.01 mug/g of hydroxyeicosatetraenoic acid in uninvolved in contrast to 4.1 +/- 1.9 mug/g in involved epidermis (P = 0.015); 23.6 +/- 5.0 ng/g of prostaglandin E2 in uninvolved in contrast to 33.1 +/- 5.7 ng/g in involved epidermis (P less than 0.01); and 21.0 +/- 4.4 ng/g of prostaglandin F2alpha in uninvolved in contrast to 39.0 +/- 5.9 ng/g in involved epidermis (P less than 0.01). The arachidonic acid and hydroxyeicosatetraenoic acid levels in involved epidermis were strongly correlated (r = 0.97). The increased levels of arachidonic acid and 12L-hydroxy-5...

‣ Fine structure of the developing epidermis in the embryo of the American alligator (Alligator mississippiensis, Crocodilia, Reptilia)

ALIBARDI, LORENZO; THOMPSON, MICHAEL B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/2001 Português
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The morphological transition from the simple epidermis that contacts the amniotic fluid of embryonic crocodilians to the adult epidermis required in a terrestrial environment has never been described. We used light and electron microscopy to study the development, differentiation and keratinisation of the epidermis of the American alligator, Alligator mississippiensis, between early and late stages of embryonic skin formation. In early embryonic development, the epidermis consists of a flat bilayer. As it develops, the bilayered epidermis comes to lie beneath the peridermis. Glycogen is almost absent from the bilayered epidermis but increases in basal and suprabasal cells when scales form. Glycogen disappears from suprabasal cells that accumulate keratin. The peridermis and 1 or 2 subperidermal layers form an embryonic epidermis that is partially or totally lost before hatching. These cells accumulate coarse filaments and form reticulate bodies. Mucous and lamellate granules are produced in the Golgi apparatus and are partly secreted extracellularly. The embryonic cells darken with the formation of larger reticulate bodies that aggregate with intermediate filaments and other cell organelles, as their nuclear chromatin condenses. Thin β-cells resembling those of scutate scales of birds develop beneath the embryonic epidermis and form a stratified β-layer that varies in thickness in different body regions. The epidermis differentiates first in the back...

‣ Flow cytometric identification of proliferative subpopulations within normal human epidermis and the localization of the primary hyperproliferative population in psoriasis

Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 01/10/1993 Português
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In this study we define the proliferative compartments of in vivo human epidermis, using specific antibodies related to cell differentiation (beta 1 and beta 4 integrins and K1/K10 differentiation keratins) and cell cycle (proliferating cell nuclear antigen [PCNA]) in combination with flow cytometric quantitation of the DNA content and optical characteristics of the cells. The beta 1 integrin (CD29) marked both of the potentially proliferative subsets in normal epidermis. One subset of normal epidermis is CD29+ K1/K10-, which was predominantly basal, and found to be comprised of slow cycling, small cells with primitive cytoplasmic organization. The vast majority (95.5%) of these cells were in a quiescent state (G0/early G1) as indicated by their lack of the cyclin, PCNA. The other proliferative subset of normal epidermis was CD29+ K1/K10+, which was suprabasal and occasional basal, highly proliferative, larger in size, and which exhibited a more complex cytoplasmic structure. Because early differentiation (K1/K10 expression) has begun in the CD29+ K1/K10+ subset, it is highly likely that they represent the proliferative population which is capable of transiently amplifying itself before terminal differentiation. Within lesional psoriatic epidermis...

‣ Epidermal differentiation in embryos of the tuatara Sphenodon punctatus (Reptilia, Sphenodontidae) in comparison with the epidermis of other reptiles

Alibardi, L; Gill, B J
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /07/2007 Português
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Studying the epidermis in primitive reptiles can provide clues regarding evolution of the epidermis during land adaptation in vertebrates. With this aim, the development of the skin of the relatively primitive reptile Sphenodon punctatus in representative embryonic stages was studied by light and electron microscopy and compared with that of other reptiles previously studied. The dermis organizes into a superficial and deep portion when the epidermis starts to form the first layers. At embryonic stages comparable with those of lizards, only one layer of the inner periderm is formed beneath the outer periderm. This also occurs in lizards and snakes so far studied. The outer and inner periderm form the embryonic epidermis and accumulate thick, coarse filaments (25–30 nm thick) and sparse alpha-keratin filaments as in other reptiles. Beneath the embryonic epidermis an oberhautchen and beta-cells form small horny tips that represent overlapping borders along the margin of beta-cells that overlap other beta-cells (in a tile-like arrangement). The tips resemble those of agamine lizards but at a small scale, forming a lamellate-spinulated pattern as previously described in adult epidermis. The embryonic epidermis matures by the dispersion of coarse filaments among keratin at the end of embryonic development and is shed around hatching. The presence of these matrix organelles in the embryonic epidermis of this primitive reptile further indicates that amniote epidermis acquired interkeratin matrix proteins early for land adaptation. Unlike the condition in lizards and snakes...

‣ The lens-regenerating competence in the outer cornea and epidermis of larval Xenopus laevis is related to pax6 expression

Gargioli, Cesare; Giambra, Vincenzo; Santoni, Sara; Bernardini, Sergio; Frezza, Domenico; Filoni, Sergio; Cannata, Stefano M
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /05/2008 Português
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After lentectomy, larval Xenopus laevis can regenerate a new lens by transdifferentiation of the outer cornea and pericorneal epidermis (lentogenic area). This process is promoted by retinal factor(s) accumulated into the vitreous chamber. To understand the molecular basis of the lens-regenerating competence (i.e. the capacity to respond to the retinal factor forming a new lens) in the outer cornea and epidermis, we analysed the expression of otx2, pax6, sox3, pitx3, prox1, βB1-cry (genes all involved in lens development) by Real-time RT-PCR in the cornea and epidermis fragments dissected from donor larvae. The same fragments were also implanted into the vitreous chamber of host larvae to ascertain their lens-regenerating competence using specific anti-lens antibodies. The results demonstrate that there is a tight correlation between lens-regenerating competence and pax6 expression. In fact, (1) pax6 is the only one of the aforesaid genes to be expressed in the lentogenic area; (2) pax6 expression is absent in head epidermis outside the lentogenic area and in flank epidermis, both incapable of transdifferentiating into lens after implantation into the vitreous chamber; (3) in larvae that have undergone eye transplantation under the head or flank epidermis...

‣ Passive and iontophoretic transport enhancement of insulin through porcine epidermis by depilatories: Permeability and fourier transform infrared spectroscopy studies

Rastogi, Sumeet K.; Singh, Jagdish
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Publicado em 14/05/2003 Português
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The effect of thioglycolate-based depilatory lotions was studied on the in vitro passive and iontophoretic permeability of insulin through porcine epidermis and biophysical changes in the stratum corneum (SC) lipids and proteins. The porcine epidermis and Franz diffusion cells modified for iontophoresis were used for the in vitro transport studies. Cathodal iontophoresis was performed at 0.2 mA/cm2 current density. Resistance of the control- and depilatory-lotion-treated epidermis was determined according to Ohmslaw. Biophysical changes were studied on porcine SC before (control) and after treatment with the depilatory lotions using Fourier transform infrared (FT-IR) spectroscopy. Asymmetric (∼2915 cm−1) and symmetric (∼2848 cm−1) Carbon-Hydrogen (C-H) stretching absorbances were studied to estimate the extent of lipid extraction. Fourier self-deconvolution and second derivative procedures were applied to amide I band (1700–1600 cm−1) in order to estimate quantitatively the changes in the secondary structure of the SC protein. The passive permeability of insulin was significantly (P<.05) increased through depilatory-lotion-treated (ie, Better Off, Marzena, and Sally Hansen) epidermis in comparison to control. Iontophoresis significantly enhanced (P<.05) the permeability of insulin through depilatory-pretreated epidermis in comparison with the control epidermis. Further...

‣ FBN-1, a fibrillin-related protein, is required for resistance of the epidermis to mechanical deformation during C. elegans embryogenesis

Kelley, Melissa; Yochem, John; Krieg, Michael; Calixto, Andrea; Heiman, Maxwell G; Kuzmanov, Aleksandra; Meli, Vijaykumar; Chalfie, Martin; Goodman, Miriam B; Shaham, Shai; Frand, Alison; Fay, David S
Fonte: eLife Sciences Publications, Ltd Publicador: eLife Sciences Publications, Ltd
Tipo: Artigo de Revista Científica
Português
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During development, biomechanical forces contour the body and provide shape to internal organs. Using genetic and molecular approaches in combination with a FRET-based tension sensor, we characterized a pulling force exerted by the elongating pharynx (foregut) on the anterior epidermis during C. elegans embryogenesis. Resistance of the epidermis to this force and to actomyosin-based circumferential constricting forces is mediated by FBN-1, a ZP domain protein related to vertebrate fibrillins. fbn-1 was required specifically within the epidermis and FBN-1 was expressed in epidermal cells and secreted to the apical surface as a putative component of the embryonic sheath. Tiling array studies indicated that fbn-1 mRNA processing requires the conserved alternative splicing factor MEC-8/RBPMS. The conserved SYM-3/FAM102A and SYM-4/WDR44 proteins, which are linked to protein trafficking, function as additional components of this network. Our studies demonstrate the importance of the apical extracellular matrix in preventing mechanical deformation of the epidermis during development. DOI: http://dx.doi.org/10.7554/eLife.06565.001

‣ The Role of AldoKeto Reductase 1C3 in Human Epidermis, Atopic Dermatitis and Cutaneous Squamous Cell Carcinoma

Mantel, Alon ; Pentland, Alice P.
Fonte: Universidade de Rochester Publicador: Universidade de Rochester
Tipo: Tese de Doutorado
Português
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Thesis (Ph.D.)--University of Rochester. School of Medicine & Dentistry. Dept. of Pharmacology and Physiology, 2011.; Aldoketo reductase 1C3 (AKR1C3) has been shown to mediate the metabolism of sex hormones and prostaglandins (PGs), both of which play a role in epidermal function and pathology. AKR1C3 expression has been initially characterized in normal human epidermis by immunofluorescence, revealing a strong expression in the differentiated epidermal layers compared with the proliferative compartment. In addition, AKR1C3 expression was up regulated during calciuminduced differentiation of primary human keratinocytes (PHKs). This suggested a possible function of AKR1C3 in keratinocyte differentiation, a tightly choreographed process that is crucial for proper function of the epidermis. The current work demonstrated that impairment of AKR1C3 during PHK differentiation altered the expression of the differentiation markers keratin 10 and loricrin, suggesting a role in keratinocyte differentiation. Prostaglandin D2 (PGD2), a preferred substrate of AKR1C3, is a lipid mediator that has been shown to be upregulated and promote inflammation in atopic dermatitis (AD). The current data showed that AKR1C3 expression is markedly upregulated by PHKs in response to PGD2...

‣ Expression of acyl-CoA synthetase 5 in human epidermis

Gaisa, N.T.; Köster, J.; Reinartz, A.; Ertmer, K.; Ehling, J.; Raupach, K.; Perez-Bouza, A.; Knüchel, R.; Gassler, N.
Fonte: Murcia : F. Hernández Publicador: Murcia : F. Hernández
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
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The human epidermis is characterized by a constant renewal of keratinocytes embedded in a matrix enriched with lipids. Numerous proteins involved in lipid metabolism are found in human epidermis, especially in keratinocytes. Long-chain acyl-CoA derivatives, which are catalyzed by human ACSL5, are important metabolites in several biochemical pathways, including ceramide de novo synthesis. The aim of the present study was to investigate expression of acyl-CoA synthetase isoform 5 (ACSL5) in human epidermis by an in situ, as well as a molecular approach. We show that ACSL5 mRNA and protein are found in human epidermis, as well as in non-differentiated and differentiated HaCaT cells. Keratinocytes of stratum spinosum are the main source for ACSL5 expression in both meshed facial or abdominal skin and ridged skin of upper or lower extremities including TUNEL-positive cells in upper cellular layers. Single keratinocytes of chronic solar-exposed meshed facial epidermis occasionally display a stronger ACSL5 immunostaining. In conclusion, our study indicates that epidermal ACSL5 expression might be involved in differentiation and the stress response of keratinocytes.

‣ Deep sequencing as a probe of normal stem cell fate and preneoplasia in human epidermis

Simons, Benjamin D.
Fonte: PNAS Publicador: PNAS
Tipo: Article; accepted version
Português
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This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by PNAS.; Using deep sequencing technology, methods based on the sporadic acquisition of somatic DNA mutations in human tissues have been used to trace the clonal evolution of progenitor cells in diseased states. However, the potential of these approaches to explore cell fate behavior of normal tissues and the initiation of preneoplasia remain underexploited. Focusing on the results of a recent deep sequencing study of eyelid epidermis, we show that the quantitative analysis of mutant clone size provides a general method to resolve the pattern of normal stem cell fate, and to detect and characterize the mutational signature of rare field transformations in human tissues, with implications for the early detection of preneoplasia.; We are indebted to Peter Campbell, Phil Jones and Inigo Martincorena for sharing information on the sizes of the biopsies used in their study, and for making their sequencing data publically available. We are also grateful to Trevor Graham, Philip Greulich and Anna Philpott for valuable discussions, and we acknowledge the financial support of the Wellcome Trust (grant number 098357/Z/12/Z).

‣ Regulation of Asymmetric Cell Divisions in the Developing Epidermis

Poulson, Nicholas
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2012 Português
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During development, oriented cell divisions are crucial for correctly organizing and shaping a tissue. Mitotic spindle orientation can be coupled with cell fate decisions to provide cellular diversity through asymmetric cell divisions (ACDs), in which the division of a progenitor cell results in two daughters with different cell fates. Proper tissue morphogenesis relies on the coupling of these two phenomena being highly regulated. The development of the mouse epidermis provides a powerful system in which to study the many levels that regulate ACDs. Within the basal layer of the epidermis, both symmetric and asymmetric cell divisions occur. While symmetric divisions allow for an increase in surface area and progenitor cell number, asymmetric divisions drive the stratification of the epidermis, directly contributing additional cell layers (Lechler and Fuchs 2005; Poulson and Lechler 2010; Williams, Beronja et al. 2011).

Utilizing genetic lineage tracing to label individual basal cells I show that individual basal cells can undergo both symmetric and asymmetric divisions. Therefore, the balance of symmetric:asymmetric divisions is provided by the sum of individual cells' choices. In addition, I define two control points for determining a cell's mode of division. First is the expression of the mInscuteable gene...

‣ Epidermis foliar de tres especies de asteráceas nativas de Argentina con potencial ornamental

Gil,SP; Seisdedos,L; Reyna,ME; Cerana,MM
Fonte: Phyton (Buenos Aires) Publicador: Phyton (Buenos Aires)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2012 Português
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Los objetivos de este trabajo fueron profundizar el estudio de la epidermis foliar de Grindelia cabrerae var. cabrerae, Solidago chilensis y Wedelia buphthalmifora, asteráceas nativas de Argentina con potencial ornamental, y determinar las variables indicadoras de adaptabilidad a un ambiente xerofítico. Se analizaron 5 hojas adultas de 5 individuos de cada población. El material se conservó en FAA. La epidermis de ambas caras de hojas maceradas en agua e hipoclorito de sodio obtenidas por raspado, fueron teñidas con safranina y montadas en agua-glicerina (1:1). De cada preparado, se escogieron 5 campos, registrándose frecuencias de células epidérmicas fundamentales, de estomas (FE) y de tricomas, largo y ancho del complejo estomático e índice estomático (IE). Los resultados obtenidos se evaluaron por métodos estadísticos. La cutícula se analizó en transcortes de hojas. Desde el punto de vista ecológico, las 3 especies presentaron caracteres epidérmicos comunes relacionados con el xeromorfismo como cutículas engrosadas, pilosidad y elevado número de estomas. Grindelia mostró células epidérmicas fundamentales con paredes rectas y mayor frecuencia de tricomas glandulares secretores de resinas. Solidago se distinguió por el tamaño reducido de las células epidérmicas fundamentales y de los estomas; se encontró un tipo de tricoma uniseriado...

‣ Ultraestructura de la epidermis foliar de Zeugites (Poaceae: Panicoideae)

Soriano,Ana María; Terrazas,Teresa; Dávila,Patricia
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 Português
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El género Zeugites incluye once especies de pastos con distribución neotropical, en México, el Caribe, Centro y Sudamérica. En este trabajo se describe la epidermis foliar de las once especies, se utilizaron técnicas de microscopía electrónica de barrido y revisaron al menos tres especímenes de cada especie, algunas muestras proceden de ejemplares de herbario y otras fueron recolectadas por la primera autora. Se presenta una clave y descripciones para las especies del género, en las cuales se resaltan las características epidérmicas distintivas. Los caracteres que resultaron informativos, desde el punto de vista taxonómico fueron: la presencia o ausencia de aguijones y macropelos, la forma de las células cortas intercostales y la forma de los cuerpos de sílice. Con base en estas características, las especies de Zeugites se pueden separar en tres grupos: (1) especies que no presentan aguijones (Z. americana, Z. mexicana, Z. pringlei, Z. munroana y Z. sagittata) y que con excepción de Z. pringlei tampoco presentan macropelos; (2) especies que presentan sólo aguijones (Z. latifolia y Z. smilacifolia); y (3) especies que presentan aguijones y macropelos (Z. capillaris, Z. hackelii, Z pittieri y Z. sylvatica). Las características morfológicas de la epidermis foliar...

‣ Effect of the fluidized bed drying on the sturcture and biosorption capability of Pb+2 of agave epidermis

Hernández-Botello,M.T.; Chanona-Pérez,J.J.; Mendoza-Pérez,J.A.; Trejo-Valdez,M.; Calderón-Domínguez,G.; Barriada Pereira,J.L.; Sastre de Vicente,M.E.; Perea-Flores,M.J.; Terres-Rojas,E.
Fonte: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería Publicador: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
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A fluidized bed drying study of agave epidermis obtained from wastes of the "pulque" manufacture was made. Drying kinetics modeling and the influence of the operation conditions on the shrinkage, micro structure and biosorption capability of Pb+2 were studied. Drying kinetics was carried out at 50, 60, 70 and 80 °C. Six semi-empirical models were tested and diffusion approach model provided the best fits. Effective diffusivity varied from 3.73xl0-9 to 6.99x10-9 m²s-1, for untreated slabs (UT) and from 3.65x 10-9 to 7.74x10-9 m²s-1 for treated samples (T) with hydrochloric acid. Activation energy was found to be 21.22 and 23.89 kJ/mol for UT and T samples respectively. Shrinkage and the microstructure changes of T slabs were larger than UT samples. T samples dried at 70 and 80 °C showed a reduction in their Pb+2 biosorption capability, caused by a large shrinkage and severe microstructural changes. For UT samples their biosorption capability was increased in relation with increase of the shrinkage and drying temperature. T samples dried at 50 and 60 °C improved their biosorption capability of Pb+2, while UT samples dried at 70 and 80 °C showed a better biosorption capability. These results can be useful for preparation of biosorbents.

‣ Estudio de la epidermis foliar en algunas especies de Bursera Jacq. ex L. (Burseraceae) y sus implicaciones taxonómicas

Castro,Mercedes E.; Torrecilla,Pedro
Fonte: Instituto de Ecología A.C., Centro Regional del Bajío Publicador: Instituto de Ecología A.C., Centro Regional del Bajío
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2013 Português
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Se realizó el estudio de las características de la epidermis foliar de seis especies de Bursera. Las muestras fueron analizadas utilizando técnicas de microscopía óptica y electrónica de barrido (MEB). Todas presentaron hojas hipostomáticas, estomas anomocíticos y el mismo tipo de tricomas glandulares y tectores, con excepción de B. karsteniana que es glabra. La micromorfología de la epidermis foliar vista al MEB mostró que todas tienen paredes anticlinales rectas, sin embargo éstas presentan una combinación única de caracteres para cada especie. Los análisis fenéticos separan dos grupos, uno formado por los tres representantes del subgénero Bursera y otro por los tres pertenecientes al subgénero Elaphrium, lo cual apoya la mencionada subdivisión. Los caracteres de la epidermis foliar mostraron un alto valor taxonómico en Bursera.