scholarly journals Evidencia molecular revela hongos asociados dentro de la orquídea epifita Laelia speciosa (HBK) Schltr.

2014 ◽  
Vol 91 (4) ◽  
pp. 523 ◽  
Author(s):  
Irene Ávila-Díaz ◽  
Roberto Garibay-Orijel ◽  
Rosa Elia Magaña-Lemus
Keyword(s):  
Laelia Speciosa

Las relaciones de orquídeas-hongos han sido estudiadas principalmente en orquídeas terrestres. El trabajo aquí presentado trata sobre la diversidad y signifi cado biológico de los hongos asociados a la orquídea epifi ta endémica Laelia speciosa. Se registró la presencia fungal en semillas, protocormos y plántulas durante la germinación y primeros estadíos de desarrollo in vitro de L. speciosa mediante evidencia molecular. Las secuencias de ITS confi rmaron la presencia de hongos en raíces, cápsulas, semillas y también en plántulas cultivadas in vitro. Ninguno de los hongos encontrados formó pelotones característicos por lo que no se asume que sean hongos micorrízicos. Se identifi caron 18 taxa de hongos pertenecientes a ocho géneros (Alternaria, Curvularia, Cylindrocarpon, Fusarium, Myrmecridium, Neonectria, Penicillium y Tetracladium) y especies desconocidas de Atractiellales, Helotiales, Hypocreales, Lasiosphaeriaceae, Nectriaceae, Sordariomycetes y Tricholomataceae. De éstos, se infi rió la biología de nueve parásitos, cuatro saprobios y dos endófi tos. Uno de los hongos, perteneciente a una especie de Helotiales coloniza todos los tejidos de la orquídea, incluyendo semillas y plántulas cultivadas in vitro; por tanto, aun si todas las precauciones son tomadas, es difícil obtener “cultivos axénicos”de L. speciosa. Existe una considerable diversidad de hongos endófi tos dentro de los órganos de L. speciosa a través de todo su ciclo de vida.

scholarly journals Callus growth and plant regeneration in Laelia speciosa (Orchidaceae)

Lankesteriana ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Irene Avila-Díaz ◽  
Marcela Esmeralda Sarabia-Ochoa ◽  
Alonso Carlos-Gómez ◽  
Rafael Salgado-Garciglia
Keyword(s):  
Plant Regeneration ◽  
Callus Growth ◽  
Laelia Speciosa

Laelia speciosa es una orquídea epífita amenazada, endémica de México. Se considera que la reproducción asexual in vitro puede ser una de las acciones para contrarrestar la extracción masiva de individuos de sus poblaciones naturales, al ofrecer plantas de calidad en el mercado. El crecimiento y diferenciación de callo derivado de explantes de hojas de L. speciosa fueron investigados en el medio de Murashige y Skoog (MS) con 30 g l-1 de sacarosa y cinco concentraciones (0.0, 0.25, 0.5, 1.0, y 2.5 g l-1) de ácido naftalenacético (ANA) en combinación con benziladenina (BA, 0.0, 0.25, 0.5, 1.0, y 2.5 g l-1). Explantes de hojas de plántulas cultivadas in vitro fueron efectivos para la formación de callo en el medio MS suplementado con 2.5 mg l-1 BA, mientras que explantes de hojas maduras no respondieron. El diámetro del callo en promedio por explante de hoja fue de 1.25 cm después de ocho semanas de cultivo. El mejor desarrollo de PLBs se reportó en el medio MS suplementado con 2.5 mg l-1 ANA and 1 mg l-1 BA. La formación de plántulas se logró exitosamente en MS suplementado con 0.5 mg l-1 de ANA y 0.1 mg l-1 de GA3. Dichas plántulas fueron aclimatadas exitosamente en invernadero con una tasa de supervivencia de 70%. 

scholarly journals Hongos endófitos de la orquídea epífita Laelia speciosa

Lankesteriana ◽  
2011 ◽  
Vol 11 (3) ◽  
Author(s):  
Roberto Garibay-Orijel ◽  
Ken Omaya ◽  
Irene Ávila-Díaz
Keyword(s):  
Laelia Speciosa

Las orquídeas mantienen en la naturaleza estrechas relaciones con hongos. Durante el trabajo con la reproducción in vitro de Laelia speciosa observamos al microscopio que semillas y plántulas presentan infestación de hongos en diversos tejidos. También se analizaron plantas adultas colectadas en el campo. Para identificar a los hongos e inferir el papel de su presencia en la planta secuenciamos su ADN. Se extrajo ADN de tejidos esterilizados superficialmente como raíz, hoja, cápsula y semillas; luego se amplificó la región del ITS ribosomal con los primers ITS1F e ITS4. Posteriormente se clonaron los fragmentos con TOPO TA4 y se secuenciaron usando la química de Big Dye terminator en un ABI 3100. En total se secuenciaron más de 150 clones positivos, de éstos el 50% correspondieron a secuencias de L. speciosa, aunque los primers empleados en teoría son específicos para hongos. El resto de las secuencias agrupadas en 97% de similitud correspondieron a 19 especies de hongos de los géneros Alternaria, Cylindrocarpon, Curvularia, Fusarium, Myrmecridium, Neonectria, Penicillium, y Tetracladium, así como a especies desconocidas de los Helotiales, Lasiosphaeriaceae, Nectriaceae, Pucciniomycotina, Sordariomycetes, y Tricholomataceae. Muchos de estos taxa están presentes en las semillas, lo que sugiere que estos hongos llegan a éstas vía placenta. En algunos casos, hongos parásitos, causan la muerte de las semillas y en otros casos, hongos micorrízicos, facilitan su germinación. La diversidad de hongos endófitos en L. speciosa es considerable y la biología de los organismos involucrados es diversa y va desde los parásitos y saprobios hasta los micorrízicos. 

In vitro propagation of the endangered orchid Laelia speciosa

2009 ◽  
Vol 99 (3) ◽  
pp. 335-343 ◽  
Author(s):  
Irene Ávila-Díaz ◽  
Ken Oyama ◽  
Carlos Gómez-Alonso ◽  
Rafael Salgado-Garciglia
Keyword(s):  
In Vitro Propagation ◽  
Endangered Orchid ◽  
Laelia Speciosa

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids

1974 ◽  
Vol 32 ◽  
pp. 132-133
Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Nuclear Ring ◽  
Rough Er ◽  
Distal Direction ◽  
In Vitro Induction

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

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