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1.
Arch Gynecol Obstet ; 309(4): 1227-1236, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38078931

RESUMEN

PURPOSE: Ectopic pregnancies include cesarean scar (CSP), cornual and cervical pregnancies. Various treatment modalities have been- described, but no standardized procedure has been defined so far. The aim of our analysis was to evaluate the diagnostics and treatment at the Department of Obstetrics and Gynecology, LMU University Hospital, Munich. METHODS: In this retrospective, single-center analysis, 24 patients treated between 2015 and 2020 were analyzed. After verification of the diagnosis by imaging and HCG-analysis, the treatment was individually determined: therapy with methotrexate (MTX) locally with or without simultaneous systemic treatment, surgical treatment via curettage, excision with uterine reconstruction even hemi hysterectomy. RESULTS: Ten patients presented with CSP, six with cervical and eight with cornual pregnancies. Median age was 34.6 years. CSP was treated with local MTX in six cases; five required additional treatment with systemic MTX or curettage. Primary curettage or surgery was performed in four cases. In cervical pregnancies the primary therapy with local MTX injection and systemic treatment was performed in 50%. One patient was treated with MTX and insertion of a Bakri balloon. Trachelectomy was required in one case. 50% of cornual pregnancies were treated with MTX locally and intramuscularly and 50% received surgery. CONCLUSION: Treatment strategies were based on the patient's individual risk parameters. The results of this study show, that simultaneous treatment with local and systemic MTX had good outcomes and could avoid surgeries.


Asunto(s)
Abortivos no Esteroideos , Embarazo Cornual , Embarazo Ectópico , Embarazo , Femenino , Humanos , Adulto , Abortivos no Esteroideos/uso terapéutico , Embarazo Cornual/diagnóstico , Embarazo Cornual/cirugía , Estudios Retrospectivos , Cesárea/efectos adversos , Embarazo Ectópico/diagnóstico , Embarazo Ectópico/cirugía , Metotrexato/uso terapéutico , Cicatriz/etiología , Resultado del Tratamiento
2.
Eur J Pharm Sci ; 185: 106438, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37001569

RESUMEN

Histamine (His) in humans is physiologically involved in neurotransmission and increases vascular permeability during the development of inflammatory response and immunity. It could be used to enhance drug-loaded nanoparticles (NPs) distribution. However, it cannot be freely delivered due to the risk of His-dose-dependent deleterious effects. His can be attached to the polymeric backbone during polymerization to overcome this limitation. In this study, His was used as an initiator of lactide polymerization, and the obtained macromolecules were subsequently used to prepare doxorubicin (DOX)-loaded NPs by nanoprecipitation and microfluidics for examination of anti-cancer properties. Notably, the in vitro activity towards gastric cancer cells (AGS) of the NPs composed of histamine-functionalized polylactides (PLAs) was greatly enhanced compared to control NPs built from hydroxy­functionalized PLAs. Furthermore, Zonula occludens-1 (ZO-1) tight junction protein production was significantly diminished after treating cells with DOX-loaded NPs assembled with PLAs with histamine residues. These results demonstrate the synergistic effect in cytotoxicity towards gastric cancer cells of DOX and the histamine that are carried by NPs. It is believed that His-DOX NPs strategy may lead to effective, targeted, and low-toxic delivery of drugs into cancer cells.


Asunto(s)
Nanopartículas , Neoplasias Gástricas , Humanos , Histamina , Neoplasias Gástricas/tratamiento farmacológico , Doxorrubicina/química , Línea Celular Tumoral , Nanopartículas/química , Sistemas de Liberación de Medicamentos/métodos
3.
Colloids Surf B Biointerfaces ; 204: 111801, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33957491

RESUMEN

The designing of biocompatible nanocarriers for the efficient delivery of their cargos to the desired targets remains a challenge. In this regard, the most promising strategy relies on the construction of pH- or thermo-responsive nanoparticles (NPs). However, it is also important to preserve the balance between the responsiveness of the carrier and their stability in physiological conditions. Therefore, we described a new family of copolymers of lactide and allyl-glycidyl ether which were subsequently modified by thiol-ene reaction to functionalize the resulting copolymer with acetylcysteine (ACC) or thioglycolic acid (tGA) moieties. Subsequently, these copolymers were used to obtain blank and doxorubicin (DOX) loaded NPs with an average diameter of about 50-100 nm. Interestingly, the NPs were stable in different pH conditions, however, the presence of ACC or tGA units in the polymeric chain allows for the reduction of the undesired burst release due to the supramolecular interactions between polymeric pedant groups and DOX. The release tests of DOX from NPs showed that DOX release rate decrease depending on the pH values and the copolymer functionalization in order of non-modified NPs > ACC-modified NPs > tGA functionalized NPs. Most importantly, the MTT assay showed that all blank NPs are non-toxic against the normal L929 cell line. Subsequently, the antitumor efficiency of the obtained NPs was tested towards L929 (murine fibroblast cell line), HeLa (cervical cancer), and AGS (human gastric adenocarcinoma cancer) cells. The results demonstrated that DOX-loaded NPs efficiently induce the reduction in the viability of the HeLa and AGS cell, and this reduction in the viability was even below 20 % for the AGS cells. Together with their biocompatibility, the obtained NPs offer a novel route for the preparation of nanocarriers for the controlled and efficient delivery of anticancer drugs.


Asunto(s)
Antineoplásicos , Nanopartículas , Animales , Antineoplásicos/farmacología , Dioxanos , Doxorrubicina/farmacología , Portadores de Fármacos , Sistemas de Liberación de Medicamentos , Compuestos Epoxi , Humanos , Concentración de Iones de Hidrógeno , Ratones
4.
Colloids Surf B Biointerfaces ; 184: 110544, 2019 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-31655303

RESUMEN

Lung cancer is the leading cause of cancer death because of smoking and air pollution. Therefore, new ideas should be provided for lung cancer treatment in which the delivery of anticancer drugs to the local tumor site can be achieved. For this purpose, we propose the use of stereocomplexed spherical microspheres with sizes between 0.5 and 10 µm loaded with doxorubicin (DOX) to be administered through the nasal route. In order to gain control over the microsphere morphology, size, and drug loading capacity, we systematically studied the influence of the solvent used for preparation and the functionalization of their building blocks, namely poly-l-lactide (PLLA) and poly-d-lactide (PDLA) with blocked or unblocked l-proline moieties. We could demonstrate that DOX release is generally determined by the size of the microspheres. The antiproliferative activity of DOX released from the different microspheres was shown in vitro using the A549 lung cancer cell line as a model. Moreover, when in direct contact to the cancer cells, smaller microspheres were uptaken and could serve as a reservoir for local drug release. Our findings not only provide a novel strategy to prepare PLA microspheres with controllable morphology and release of anti-cancer drugs but also offer additional possibilities for the application of stereocomplexed particles in anticancer therapy, with suitable sizes for nasal administration.


Asunto(s)
Antibióticos Antineoplásicos/farmacología , Doxorrubicina/farmacología , Microesferas , Poliésteres/química , Células A549 , Antibióticos Antineoplásicos/química , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/química , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Estructura Molecular , Tamaño de la Partícula , Estereoisomerismo , Propiedades de Superficie
5.
Eur J Med Res ; 9(8): 371-7, 2004 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-15337626

RESUMEN

Nucleoside analogues can induce toxic effects on mitochondria by inhibiting the human DNA polymerase-gamma. The clinically observed toxicities can range from slightly increased serum lactate levels to potentially severe and fatal lactic acidosis. A growing interest exists for detection of changes in mitochondrial (mt) DNA content in patients receiving antiretroviral therapy (HAART). Most studies use peripheral blood mononuclear cell (PBMC) fractions to investigate mt DNA content via Real-Time PCR in patients, not accounting platelets falsifying the mitochondrial (mt)DNA:nuclear (n)DNA-ratio. In this study we suggest a procedure to eliminate disturbing platelets totally. 8 healthy controls (G1), 6 therapy-naive HIV-infected patients (G2) and 9 HIV-infected patients under HAART (G3) were examined for mtDNA:nDNA-ratio using Real-Time PCR technology. Different blood collection and/or PBMC isolation strategies were analysed for variances of outcome at examinations of the same blood donor. Using DNA prepared of whole blood specimens, mtDNA:nDNA-ratios showed no differences in all investigated groups (G1, G2, G3). Comparing mtDNA:nDNA-ratios of platelet-depleted PBMC fractions of G1 with G2 revealed a reduction of 22% (p = 0.128) and a steeper reduction of 40% (p = 0.0036) comparing specimens of G1 with G3. Scrutinising differently processed specimens within the groups themselves, in G2 whole blood versus platelet-containing PBMC specimens showed a difference in mtDNA:nDNA-ratios of 26% (p = 0.0406), whereas a comparison of whole blood versus platelet-free PBMC specimens led to a comparatively more distinct reduction of 35% (p = 0.0089). The same effect was seen in G3, where whole blood versus platelet-containing PBMC specimens revealed a reduction of 32% (p = 0.01) and whole blood versus platelet-free PBMC specimens showed a 42% (p = 0.0011) decrease. Furthermore analysing each single patient in relation to the different methods, a minor fluctuation margin could be found using platelet-free PBMC specimens for Real-Time PCR. Using platelet-free PBMCs for mt DNA content detection, a correlation of low mtDNA:nDNA-ratios to clinical signs, like elevated lactate levels or lipodystrophy, could be observed. Light-microscopic evaluation for platelets, comparing platelet-containing PBMC fractions versus platelet-depleted PBMC fractions reinforced the Real-Time PCR results. Our data demonstrate that the first step of the blood sample collection/preparation is critical for valid illustration of mt DNA content in HIV-infected patients using ultra-sensitive Real-Time PCR technology. The use of serum tubes for blood collection is an easy and low-cost alternative to expensive cell sorting for elimination of disturbing platelets. Using platelet-free PBMC fractions for measurement mt DNA content could be a surrogate marker for clinical signs mediated by HAART.


Asunto(s)
Plaquetas , ADN Mitocondrial/sangre , Reacción en Cadena de la Polimerasa/métodos , Proyectos de Investigación , Síndrome de Inmunodeficiencia Adquirida/sangre , Artefactos , Núcleo Celular/genética , Núcleo Celular/metabolismo , Separación Celular , Estudios Transversales , Ácido Edético , Femenino , Humanos , Masculino
6.
Toxicol Lett ; 128(1-3): 129-44, 2002 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-11869824

RESUMEN

Interactions of 27 steroids, among them 17 derivatives such as ethers, sulfates and amidosulfonates derived from 17 beta- and 17 alpha-estradiol, from testosterone and alpha- and beta-dihydrotesosterone and from dehydroepiandrosterone with rat liver microsomal cytochromes P450 (P450) were investigated in vitro by assessing binding to P450 and effects on P450 mediated monooxygenase functions as measured by different model reactions: ethoxyresorufin O-deethylation (EROD), ethoxycoumarin O-deethylation (ECOD) and ethylmorphine N-demethylation (EMND). With the exception of 17 alpha-estradiol-3-dimethylamidosulfonate, estrone, its -3-methylether and -3-amidosulfonate and testosterone, all other steroids displayed type I or reverse type I binding to P450. All steroids inhibited EROD activity in micromolar concentrations. An additional strong inhibition of ECOD and EMND activities was only demonstrated for the androgens and progestins. Estriol, estrone and mestranol displayed less inhibitory actions on the model reactions than estradiol. No major differences in comparison to the parent compounds were noted with the other derivatives. The only exceptions were 17 beta-(8,9-dehydro-14 alpha,15 alpha-methylene)estradiol, which displayed stronger effects than estradiol, and dehydroepiandrosterone-3-sulfate, which was less effective than dehydroepiandrosterone. Possible antioxidant properties of the steroids were examined by the stimulated lipid peroxidation (LPO), H2O2 production, and lucigenin (LC) and luminol (LM) amplified chemiluminescence (CL) using rat liver microsomes. Additionally, the influence on rat whole blood chemiluminescence (WB-CL) was assessed. All the estrogens, but not their methylethers and amidosulfonates inhibited LPO in micromolar concentrations. The effects on the other oxidase model reactions or on WB-CL were less distinct. Only ethinylestradiol and 17 beta-(8,9-dehydro-14 alpha,15 alpha-methylene)estradiol displayed a strong inhibitory action on all model reactions. With the exception of dehydroepiandrosterone-3-sulfate, which in general had only weak effects, the androgen and progestin derivatives, in contrast, strongly decreased H2O2 formation and LM- and LC-CL, but were mostly ineffective on LPO and WB-CL.


Asunto(s)
Androstenodiona/análogos & derivados , Sistema Enzimático del Citocromo P-450/metabolismo , Deshidroepiandrosterona/análogos & derivados , Estradiol/análogos & derivados , Microsomas Hepáticos/efectos de los fármacos , 7-Alcoxicumarina O-Dealquilasa/metabolismo , Androstenodiona/metabolismo , Androstenodiona/farmacología , Animales , Citocromo P-450 CYP1A1/metabolismo , Deshidroepiandrosterona/metabolismo , Deshidroepiandrosterona/farmacología , Estradiol/metabolismo , Estradiol/farmacología , Etilmorfina-N-Demetilasa/metabolismo , Hígado/metabolismo , Mediciones Luminiscentes , Masculino , Microsomas Hepáticos/enzimología , Microsomas Hepáticos/metabolismo , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , Testosterona/análogos & derivados , Testosterona/metabolismo , Testosterona/farmacología
7.
Plant J ; 28(2): 145-57, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11722758

RESUMEN

Different alpha-tubulin cDNA sequences fused in an antisense orientation to a CaMV 35S promoter were introduced into Arabidopsis thaliana plants. Several independent transgenic lines that showed a moderate but clear reduction of alpha-tubulin gene expression (TUA6/AS lines) were obtained and phenotypically characterized. Although no apparent abnormalities were detected in the aerial parts of TUA6/AS plants, root development was severely affected. Cells in TUA6/AS root tips were found to contain aberrant microtubular structures, to expand abnormally and to be unable to undergo regular cell division. These cellular defects caused a dramatic radial expansion of the root tip and inhibited root elongation. In addition, TUA6/AS roots displayed ectopic formation of root hairs, root hair branching and a reduced ability to respond to gravitropic challenges. Our results contribute to an improved understanding of the different roles microtubules play during root development and demonstrate that reverse genetics is a powerful tool to analyze cytoskeletal functions during plant organogenesis.


Asunto(s)
Arabidopsis/fisiología , Regulación de la Expresión Génica de las Plantas , Gravitropismo/fisiología , Raíces de Plantas/crecimiento & desarrollo , Tubulina (Proteína)/genética , Cinética , Meristema/fisiología , Raíces de Plantas/citología , Plantas Modificadas Genéticamente/fisiología
9.
Plant Cell ; 13(6): 1333-46, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11402164

RESUMEN

Based mostly on the results of in vitro experiments, ADF (actin-depolymerizing factor) proteins are thought to be key modulators of the dynamic organization of the actin cytoskeleton. The few studies concerned with the in vivo function of ADF proteins that have been reported to date were performed almost exclusively using single-cell systems and have failed to produce consistent results. To investigate ADF functions in vivo and during the development of multicellular organs, we generated transgenic Arabidopsis plants that express a cDNA encoding an ADF protein (AtADF1) in the sense or the antisense orientation under the control of a strong constitutively active promoter. Selected lines with significantly altered levels of AtADF protein expression were characterized phenotypically. Overexpression of AtADF1 resulted in the disappearance of thick actin cables in different cell types, caused irregular cellular and tissue morphogenesis, and reduced the growth of cells and organs. In contrast, reduced AtADF expression promoted the formation of actin cables, resulted in a delay in flowering, and stimulated cell expansion as well as organ growth. These results are consistent with the molecular functions of ADF as predicted by in vitro studies, support the global roles of ADF proteins during the development of a multicellular organism, and demonstrate that these proteins are key regulators of F-actin organization, flowering, and cell and organ expansion in Arabidopsis.


Asunto(s)
Actinas/metabolismo , Arabidopsis/fisiología , Proteínas de Microfilamentos/fisiología , Proteínas de Plantas/fisiología , Factores Despolimerizantes de la Actina , Actinas/química , Arabidopsis/crecimiento & desarrollo , División Celular , Destrina , Hipocótilo/citología , Hipocótilo/ultraestructura , Plantas Modificadas Genéticamente
10.
Plant Mol Biol ; 45(5): 517-27, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11414611

RESUMEN

Actin depolymerizing factor (ADF) is a key regulator of the organization of the actin cytoskeleton during various cellular activities. We found that ADF genes in Arabidopsis form a large family consisting of at least nine members, four of which were cloned and sequenced in this study. Comparison of genomic and cDNA sequences showed that the AtADF1, AtADF5, and AtADF6 genes all contain two introns at conserved positions. Analysis of transgenic Arabidopsis plants carrying promoter-GUS fusion constructs revealed that AtADF1 and AtADF6 are expressed in the vascular tissues of all organs, whereas expression of AtADF5 is restricted to the root tip meristem. GFP-AtADFI, GFP-AtADF5, and GFP-AtADF6 fusion proteins were found to bind to actin filaments in vivo, and to reorganize the actin cytoskeleton when transiently expressed in plant cells.


Asunto(s)
Actinas/metabolismo , Arabidopsis/genética , Proteínas del Citoesqueleto/genética , Proteínas de Microfilamentos/genética , Factores Despolimerizantes de la Actina , Secuencia de Aminoácidos , Arabidopsis/metabolismo , Northern Blotting , Clonación Molecular , Proteínas del Citoesqueleto/metabolismo , Destrina , Etiquetas de Secuencia Expresada , Glucuronidasa/genética , Glucuronidasa/metabolismo , Proteínas Fluorescentes Verdes , Intrones , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Proteínas de Microfilamentos/metabolismo , Microscopía Fluorescente , Datos de Secuencia Molecular , Estructuras de las Plantas/anatomía & histología , Estructuras de las Plantas/metabolismo , ARN Mensajero/análisis , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Alineación de Secuencia
11.
Plant Cell ; 12(7): 1137-52, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10899980

RESUMEN

The formation of the cell plate, a unique structure in dividing plant cells, is pivotal for cytokinesis. A mutation in the Arabidopsis KORRIGAN (KOR) gene causes the formation of aberrant cell plates, incomplete cell walls, and multinucleated cells, leading to severely abnormal seedling morphology. The mutant, designed kor1-2, was identified as a stronger allele than the previously identified kor1-1, which appears to be defective only in cell elongation. KOR1 encodes an endo-1,4-beta-d-glucanase with a transmembrane domain and two putative polarized targeting signals in the cytosolic tail. When expressed in tobacco BY2 cells, a KOR1-GFP (green fluorescence protein) fusion protein was localized to growing cell plates. Substitution mutations in the polarized targeting motifs of KOR1 caused the fusion proteins to localize to the plasma membrane as well. Expression of these mutant genes in kor1-2 plants complemented only the cell elongation defect but not the cytokinesis defect, indicating that polarized targeting of KOR1 to forming cell plates is essential for cytokinesis. Our results suggest that KOR1 plays a critical role during cytokinesis.


Asunto(s)
Arabidopsis/enzimología , Ciclo Celular/genética , Celulasa/metabolismo , Secuencia de Aminoácidos , Arabidopsis/citología , Secuencia de Bases , Celulasa/química , Celulasa/genética , Proteínas Fluorescentes Verdes , Proteínas Luminiscentes/genética , Datos de Secuencia Molecular , Mutación , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Homología de Secuencia de Aminoácido
12.
Plant Physiol ; 122(1): 35-48, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10631247

RESUMEN

In an attempt to elucidate the biological function of villin-like actin-binding proteins in plants we have cloned several genes encoding Arabidopsis proteins with high homology to animal villin. We found that Arabidopsis contains at least four villin-like genes (AtVLNs) encoding four different VLN isoforms. Two AtVLN isoforms are more closely related to mammalian villin in their primary structure and are also antigenically related, whereas the other two contain significant changes in the C-terminal headpiece domain. RNA and promoter/beta-glucuronidase expression studies demonstrated that AtVLN genes are expressed in all organs, with elevated expression levels in certain types of cells. These results suggest that AtVLNs have less-specialized functions than mammalian villin, which is found only in the microvilli of brush border cells. Immunoblot experiments using a monoclonal antibody against pig villin showed that AtVLNs are widely distributed in a variety of plant tissues. Green fluorescent protein fused to full-length AtVLN and individual AtVLN headpiece domains can bind to both animal and plant actin filaments in vivo.


Asunto(s)
Arabidopsis/metabolismo , Proteínas Portadoras/metabolismo , Proteínas de Microfilamentos/metabolismo , Proteínas de Plantas/metabolismo , Secuencia de Aminoácidos , Animales , Arabidopsis/genética , Proteínas Portadoras/genética , Chlorocebus aethiops , Proteínas de Microfilamentos/genética , Microscopía Confocal , Datos de Secuencia Molecular , Proteínas de Plantas/genética , Plantas Tóxicas , Homología de Secuencia de Aminoácido , Nicotiana/citología , Nicotiana/metabolismo , Células Vero
13.
Curr Opin Plant Biol ; 2(6): 462-70, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10607658

RESUMEN

The plant cytoskeleton has crucial functions in a number of cellular processes that are essential for cell morphogenesis, organogenesis and development. These functions have been intensively investigated using single cell model systems. With the recent characterization of plant mutants that show aberrant organogenesis resulting from primary defects in cytoskeletal organization, an integrated understanding of the importance of the cytoskeleton for plant development has begun to emerge. Newly established techniques that allow the non-destructive visualization of microtubules or actin filaments in living plant cells and organs will further advance this understanding.


Asunto(s)
Citoesqueleto/fisiología , Desarrollo de la Planta , Diferenciación Celular , División Celular , Citoesqueleto/genética , Células Vegetales , Plantas/genética
14.
Development ; 126(24): 5559-68, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10572033

RESUMEN

Arabidopsis thaliana trichomes provide an attractive model system to dissect molecular processes involved in the generation of shape and form in single cell morphogenesis in plants. We have used transgenic Arabidopsis plants carrying a GFP-talin chimeric gene to analyze the role of the actin cytoskeleton in trichome cell morphogenesis. We found that during trichome cell development the actin microfilaments assumed an increasing degree of complexity from fine filaments to thick, longitudinally stretched cables. Disruption of the F-actin cytoskeleton by actin antagonists produced distorted but branched trichomes which phenocopied trichomes of mutants belonging to the 'distorted' class. Subsequent analysis of the actin cytoskeleton in trichomes of the distorted mutants, alien, crooked, distorted1, gnarled, klunker and wurm uncovered actin organization defects in each case. Treatments of wild-type seedlings with microtubule-interacting drugs elicited a radically different trichome phenotype characterized by isotropic growth and a severe inhibition of branch formation; these trichomes did not show defects in actin cytoskeleton organization. A normal actin cytoskeleton was also observed in trichomes of the zwichel mutant which have reduced branching. ZWICHEL, which was previously shown to encode a kinesin-like protein is thought to be involved in microtubule-linked processes. Based on our results we propose that microtubules establish the spatial patterning of trichome branches whilst actin microfilaments elaborate and maintain the overall trichome pattern during development.


Asunto(s)
Actinas/fisiología , Arabidopsis/embriología , Depsipéptidos , Arabidopsis/genética , Compuestos Bicíclicos Heterocíclicos con Puentes , Citoesqueleto/fisiología , Microtúbulos , Morfogénesis , Mutagénesis , Péptidos Cíclicos , Faloidina , Fenotipo , Plantas Modificadas Genéticamente , Tiazoles , Tiazolidinas
15.
J Cell Biol ; 145(2): 317-30, 1999 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-10209027

RESUMEN

Pollen tube cells elongate based on actin- dependent targeted secretion at the tip. Rho family small GTPases have been implicated in the regulation of related processes in animal and yeast cells. We have functionally characterized Rac type Rho family proteins that are expressed in growing pollen tubes. Expression of dominant negative Rac inhibited pollen tube elongation, whereas expression of constitutive active Rac induced depolarized growth. Pollen tube Rac was found to accumulate at the tip plasma membrane and to physically associate with a phosphatidylinositol monophosphate kinase (PtdIns P-K) activity. Phosphatidylinositol 4, 5-bisphosphate (PtdIns 4, 5-P2), the product of PtdIns P-Ks, showed a similar intracellular localization as Rac. Expression of the pleckstrin homology (PH)-domain of phospholipase C (PLC)-delta1, which binds specifically to PtdIns 4, 5-P2, inhibited pollen tube elongation. These results indicate that Rac and PtdIns 4, 5-P2 act in a common pathway to control polar pollen tube growth and provide direct evidence for a function of PtdIns 4, 5-P2 compartmentalization in the regulation of this process.


Asunto(s)
Arabidopsis/fisiología , Proteínas de Unión al GTP/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Polen/fisiología , Secuencia de Aminoácidos , Arabidopsis/ultraestructura , Células Cultivadas , GTP Fosfohidrolasas/metabolismo , Proteínas de Unión al GTP/química , Proteínas de Unión al GTP/genética , Glicosilación , Isoenzimas/metabolismo , Datos de Secuencia Molecular , Fosfolipasa C delta , Proteínas de Plantas/metabolismo , Estructuras de las Plantas , Plantas Tóxicas , Polen/ultraestructura , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Nicotiana , Transfección , Fosfolipasas de Tipo C/metabolismo , Proteínas de Unión al GTP rac
16.
Plant J ; 16(3): 393-401, 1998 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9881160

RESUMEN

The C-terminus of mouse talin (amino acids 2345-2541) is responsible for all of the protein's f-actin binding capacity. Unlike full-length talin, the C-terminal f-actin binding domain is unable to nucleate actin polymerization. We have found that transient and stable expression of the talin actin-binding domain fused to the C-terminus of the green fluorescent protein (GFP-mTn) can visualize the actin cytoskeleton in different types of living plant cells without affecting cell morphology or function. Transiently expressed GFP-mTn co-localized with rhodamine-phalloidin in permeabilized tobacco BY-2 suspension cells, showing that the fusion protein can specifically label the plant actin cytoskeleton. Constitutive expression of GFP-mTn in transgenic Arabidopsis thaliana plants visualized actin filaments in all examined tissues with no apparent effects on plant morphology or development at any stage during the life cycle. This demonstrates that in a number of different cell types GFP-mTn can serve as a non-invasive marker for the actin cytoskeleton. Confocal imaging of GFP-mTn labeled actin filaments was employed to reveal novel information on the in vivo organization of the actin cytoskeleton in transiently transformed, normally elongating tobacco pollen tubes.


Asunto(s)
Actinas/metabolismo , Arabidopsis/metabolismo , Citoesqueleto/metabolismo , Talina/metabolismo , Animales , Arabidopsis/crecimiento & desarrollo , Línea Celular , Proteínas Fluorescentes Verdes , Proteínas Luminiscentes/metabolismo , Ratones , Plantas Modificadas Genéticamente , Plantas Tóxicas , Proteínas Recombinantes de Fusión/metabolismo , Nicotiana/metabolismo
17.
Plant Cell Rep ; 12(1): 50-4, 1992 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24201731

RESUMEN

We present protocols for the regeneration of fertile plants from immature zygotic embryos of Arabidopsis thaliana ecotype "Zürich" either directly by multiple shoot formation from the apical region or indirectly by shoot induction from embryo derived calli. The regeneration efficiency by "multiple shooting" depended on the developmental stage of the cultured embryos and ranged from 15% for early heart shaped to 90% for early torpedo shaped and further developed embryos. 85% callus induction was achieved from embryos in the early torpedo shaped or a later stage of development. The efficiency of shoot induction from embryo derived calli varied between 25% and 75% in different experiments.

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