Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 327
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Int Arch Occup Environ Health ; 93(3): 325-335, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31732795

RESUMEN

PURPOSE: Selenium (Se) is an essential trace element, which however, exhibits a narrow safe range of intake. Selenium also occurs at several workplaces, which results in an inhalative selenium exposure of the employees. Thus, an efficient exposure assessment strategy is demanded. The most established parameter, selenium in plasma, mostly consists of protein-bound selenium. This study aimed to investigate urinary total selenium (Se-U) as an additional biomarker of recent human occupational exposure to elemental and inorganic selenium. METHODS: Pre- and post-shift urine samples from employees with exposure to selenium-containing dust were analyzed to total selenium and compared with Se levels in urine samples from controls without occupational exposure to selenium as well as correlated with the recent ambient Se exposure by personal air monitoring. RESULTS: Se-U in post-shift samples was considerably increased compared to the levels in pre-shift samples as well as to the controls. However, Se-U in pre-shift urine was elevated compared to the Se-U in controls too. Se-U in post-shift urine and even better the shift increment in Se-U correlated with the air exposure of the present shift. A rough estimation by Se-U shift increment and external exposure accounted for an inhalative resorption rate of about 1%. CONCLUSION: Our data indicate that Se-U can display the exposure. Pre-shift Se-U levels may be based on previous exposure and indicate a slow urinary elimination kinetics. The results hint for a rather low resorption rate of selenium and inorganic selenium compounds via the lung.


Asunto(s)
Biomarcadores/orina , Exposición Profesional/análisis , Selenio/orina , Adulto , Monitoreo del Ambiente/métodos , Femenino , Humanos , Exposición por Inhalación/análisis , Masculino , Persona de Mediana Edad , Adulto Joven
2.
J Eur Acad Dermatol Venereol ; 34(2): 377-384, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31494974

RESUMEN

BACKGROUND: Chronic viral infections caused by highly contagious human papillomaviruses (HPVs) from the alpha genus are a substantial risk factor for tumour diseases. OBJECTIVES: The goal of this study was to compare the HPV infection pattern with histology in a patient group of immunocompromised HIV+ and non-immunocompromised patients with anal intraepithelial neoplasia. MATERIALS AND METHODS: Tissue samples (n = 210) from the anogenital area of 121 patients underwent retrospective histological and molecular examination for HPV DNA prevalence by chip analysis. The study was part of a cancer screening from the Dermatology Department of the LMU Munich, Germany. All data were collected and processed anonymously. RESULTS: HPV 6 or 11 are more abundant in tissue samples from histologically diagnosed condylomata acuminata (47.7%) compared to grade 1, 2, and 3 intraepithelial neoplasias (IN 1-3). Detection of high-risk (hr) alpha-HPV DNA was significantly higher in tissue samples from IN 3 (67.5%) compared to IN 1 and 2 (12.9%), and compared to condylomata acuminata (29.5%). No HPV types were detected in histologically unremarkable tissue samples. There was a significant association between the prevalence of HPV 16 and the classifications IN 1 to IN 3 (χ2 (2) = 13.62, P = 0.001). We identified a significant correlation between the prevalence of high-risk and low-risk (lr) HPV types and HIV, especially mixed infections of different HPV types correlated with high-grade IN. Based on the present data, we suggest the risk of carcinoma in HIV+/- patients (RICH) score and test it in the 121 patients. CONCLUSIONS: hr alpha-HPVs, mainly HPV 16, are associated with increased oncogenic potential of premalignant lesions (IN 1-3), especially in HIV+ patients. Based on the combination of HIV/HPV-testing and histological analysis, we identified correlations that could potentially forecast the risk of malignant transformation and summarized them in the form of RICH score.


Asunto(s)
Alphapapillomavirus/aislamiento & purificación , Neoplasias del Ano/virología , Infecciones por VIH/complicaciones , Infecciones por Papillomavirus/virología , Infecciones Tumorales por Virus/virología , Neoplasias del Cuello Uterino/virología , Adulto , Neoplasias del Ano/complicaciones , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infecciones por Papillomavirus/complicaciones , Estudios Retrospectivos , Infecciones Tumorales por Virus/complicaciones , Neoplasias del Cuello Uterino/complicaciones
3.
BMC Vet Res ; 13(1): 210, 2017 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-28673347

RESUMEN

BACKGROUND: There are no available studies describing the possible resistance of strongyles to ivermectin in horses in Poland. One hundred seventy three horses from nine stud farms from South-Western Poland were studied. The effectiveness of ivermectin was studied on the 14th day after ivermectin administration using the fecal egg count reduction test, and a long-term observation of the egg reappearance period was carried out. The fecal study was carried out using a modified McMaster method, which typically detects 20 eggs per gram of stool. The results were subjected to statistical analysis that enabled quantification of the eggs in the stool samples. RESULTS: The study revealed high efficacy of ivermectin on the 14th day after administration without a shortening of the egg reappearance period. CONCLUSION: The results indicate that strongyles resistance to ivermectin in Poland is not a serious problem.


Asunto(s)
Antihelmínticos/farmacología , Ivermectina/farmacología , Infecciones Equinas por Strongyloidea/tratamiento farmacológico , Animales , Antihelmínticos/uso terapéutico , Resistencia a Medicamentos , Heces/parasitología , Femenino , Enfermedades de los Caballos , Caballos , Ivermectina/uso terapéutico , Masculino , Recuento de Huevos de Parásitos/veterinaria , Polonia , Strongyloidea/aislamiento & purificación
4.
Health Promot J Austr ; 26(3): 241-245, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26411327

RESUMEN

Mature minor consent only became available in Australia in 2007. There is neither an explicitly defined protocol, nor a clear definition evident in the literature relating to use of the mature minor concept in health research. Due to difficulties in defining fixed age ranges to varying levels of maturity and vulnerability, there is a lack of clarity surrounding when it might be reasonable and ethical to apply for or grant a waiver for parental consent. This paper describes the challenges faced and solutions created when gaining approval for use of mature minor consent in a respondent-driven sampling (RDS) study to explore the social norms and alcohol consumption among 14-17-year-old adolescents (n = 1012) in the community. The University's Human Research Ethics Committee granted mature minor consent for this study, and the techniques applied enabled recruitment of adolescents from community-based settings through use of RDS to achieve the required sample. This paper has relevance for research that requires a waiver for parental consent; it presents a case study for assessing mature minors and makes recommendations on how ethical guidelines can be improved to assist human research ethics application processes.


Asunto(s)
Ética en Investigación , Consentimiento Paterno/ética , Selección de Paciente/ética , Sujetos de Investigación , Normas Sociales , Consumo de Alcohol en Menores/ética , Adolescente , Australia , Femenino , Humanos , Masculino
5.
Internist (Berl) ; 55(7): 847-50, 2014 Jul.
Artículo en Alemán | MEDLINE | ID: mdl-24736934

RESUMEN

The case of a 77-year-old woman who was admitted with resistant arterial hypertension is reported. In view of a history of pheochromocytoma 2 years ago, catecholamine levels were examined and found to be elevated; in addition, MIBG scintigraphy showed a positive area in the anterior mediastinum. Computer tomography showed a tumor in the sternum. Histology confirmed metastasis from the pheochromocytoma, and the corpus was removed surgically. Currently, the patient is without any evidence of relapse.


Asunto(s)
Hipertensión/etiología , Hipertensión/prevención & control , Feocromocitoma/secundario , Feocromocitoma/cirugía , Neoplasias Torácicas/secundario , Neoplasias Torácicas/cirugía , Anciano , Diagnóstico Diferencial , Femenino , Humanos , Hipertensión/diagnóstico , Feocromocitoma/complicaciones , Neoplasias Torácicas/complicaciones , Resultado del Tratamiento
6.
J Equine Vet Sci ; 133: 104988, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38157949

RESUMEN

The purpose of the study was to determine the histo-morphological effects on villous synovium after synovectomy using two different motorized synovial resectors and two different intensities ex-vivo. Thirty-three (n = 33) equine metacarpophalangeal/metatarsophalangeal joints were used. Synovectomy was performed along the dorsomedial/dorsolateral synovium (n = 66) using two motorized synovial resectors (aggressive full radius resector, AFRR, used at two intensities: single treatment, n = 24 vs. triple treatment, n = 21 vs. aggressive meniscus side cutter, AMSC, n = 21). Arthroscopic images were evaluated blindly for resector type and intensity. Histological images were evaluated descriptive for synovial morphology and the extent of tissue loss using a microscopic scale. Scanning electron microscopy described the synovial morphology. The synovectomized areas were specific for each resector used and distinguishable from arthroscopic images. The AFRR demonstrated a clear demarcation between treated and non-treated areas and removed the stratum synoviale completely including parts of the underlying stratum fibrosum. In contrast, the AMSC showed less clear demarcation, villous scaffolds and no involvement of the stratum fibrosum. Triple intense treated AFFR samples resulted in significantly deeper lesions compared to single treatments (p = 0.037) but could not be distinguished on arthroscopic images. The morphological effects on villous synovium differ according to the resector type used. The extent of synovial tissue loss cannot be estimated from arthroscopic images but histologically. The type and use of motorized synovial resector determines the morphological alterations of the treated synovium. Arthroscopic control is considered unsuitable to control synovectomy depth.


Asunto(s)
Artroscopía , Sinovectomía , Caballos , Animales , Sinovectomía/veterinaria , Artroscopía/métodos , Artroscopía/veterinaria , Membrana Sinovial/patología , Membrana Sinovial/ultraestructura
7.
Clin Genet ; 83(2): 145-54, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22369279

RESUMEN

Higher resolution whole-genome arrays facilitate the identification of smaller copy number variations (CNVs) and their integral genes contributing to autism and/or intellectual disability (ASD/ID). Our study describes the use of one of the highest resolution arrays, the Affymetrix(®) Cytogenetics 2.7M array, coupled with quantitative multiplex polymerase chain reaction (PCR) of short fluorescent fragments (QMPSF) for detection and validation of small CNVs. We studied 82 subjects with ASD and ID in total (30 in the validation and 52 in the application cohort) and detected putatively pathogenic CNVs in 6/52 cases from the application cohort. This included a 130-kb maternal duplication spanning exons 64-79 of the DMD gene which was found in a 3-year-old boy manifesting autism and mild neuromotor delays. Other pathogenic CNVs involved 4p14, 12q24.31, 14q32.31, 15q13.2-13.3, and 17p13.3. We established the optimal experimental conditions which, when applied to select small CNVs for QMPSF confirmation, reduced the false positive rate from 60% to 25%. Our work suggests that selection of small CNVs based on the function of integral genes, followed by review of array experimental parameters resulting in highest confirmation rate using multiplex PCR, may enhance the usefulness of higher resolution platforms for ASD and ID gene discovery.


Asunto(s)
Trastorno Autístico/genética , Análisis Citogenético/métodos , Variaciones en el Número de Copia de ADN , Discapacidad Intelectual/genética , Trastorno Autístico/diagnóstico , Estudios de Cohortes , Genoma Humano , Humanos , Discapacidad Intelectual/diagnóstico , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Reacción en Cadena de la Polimerasa/métodos
8.
Pol J Vet Sci ; 26(3): 401-407, 2023 09 20.
Artículo en Inglés | MEDLINE | ID: mdl-37727101

RESUMEN

Parasitosis in horses may be uncontrolled and expose breeders and owners to serious financial losses or, possibly, to the loss of animals. Therefore, the prevention and monitoring of the development of parasitic diseases should play an important role in the breeding process. The aim of this study was to confirm the influence of factors such as age, breed, herd size, deworming program, and type of anthelmintics, on the prevalence and intensity of parasites (helminths) in domestic horses in Lower Silesia. The study was carried out between August and November of 2020. The samples of horse feces were collected from 50 different stables in the area of Lower Silesia, Poland. A total of 286 individuals from various breeds were examined. Detailed analysis revealed that the mean age of infected horses was significantly lower than in uninfected horses. The mean time since the last deworming procedure was almost twice as low in uninfected horses than in infected ones. Additionally, the deworming agent affects the prevalence of infection. The analysis was also performed for the same factors in reference to quantitative data. The mean EPG was four-fold higher in juvenile horses than in adults and three-fold higher when the horses were dewormed with the use of fenbendazole instead of ivermectin or ivermectin with praziquantel combined.


Asunto(s)
Fenbendazol , Ivermectina , Caballos , Animales , Estudios Transversales , Polonia/epidemiología , Heces
9.
J Acoust Soc Am ; 132(3): EL169-75, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22979828

RESUMEN

Simultaneous long-term monitoring of underwater sound and ship traffic provided an opportunity to study how low-frequency noise correlated with ocean-based commercial shipping trends. Between 2007 and 2010 changes in regional shipping off southern California occurred as a consequence of economic and regulatory events. Underwater average noise levels measured before and during these events showed a net reduction of 12 dB. Statistical models revealed that a reduction of 1 ship transit per day resulted in 1 dB decrease in average noise. This synthesis of maritime traffic statistics with ocean noise monitoring provides an important step in understanding the magnitude and potential effects of chronic noise in marine habitats.


Asunto(s)
Recesión Económica , Ruido del Transporte/prevención & control , Navíos/economía , Recesión Económica/tendencias , Ecosistema , Monitoreo del Ambiente/métodos , Análisis de Fourier , Modelos Estadísticos , Movimiento (Física) , Ruido del Transporte/economía , Ruido del Transporte/estadística & datos numéricos , Océanos y Mares , Navíos/legislación & jurisprudencia , Navíos/estadística & datos numéricos , Sonido , Espectrografía del Sonido , Factores de Tiempo , Agua
10.
J Exp Biol ; 213(Pt 8): 1272-80, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20348339

RESUMEN

The primary olfactory centres of the sphinx moth Manduca sexta, the antennal lobes, contain a small number of sexually dimorphic glomeruli: the male-specific macroglomerular complex and the large female glomeruli. These glomeruli play important roles in sex-specific behaviours, such as the location of conspecific females and the selection of appropriate host plants for oviposition. The development of sexually dimorphic glomeruli depends strictly on the ingrowth of sex-specific olfactory receptor cell afferents. In the present study we tested the role of female-specific olfactory receptor cells (ORCs) in mediating female-specific host plant approach behaviour and in determining the response of downstream antennal lobe neurons. We generated male gynandromorphs by excising one imaginal disc from a male larva and replacing it with the antennal imaginal disc from a female donor. Most male gynandromorphs had an apparently normal female antenna and a feminised antennal lobe. These gynandromorphs were tested for flight responses in a wind tunnel towards tomato plants, a preferred host plant for oviposition in M. sexta. Male gynandromorphs landed on host plants as often as normal females, demonstrating that the presence of the induced female-specific glomeruli was necessary and sufficient to produce female-like, odour-oriented behaviour, i.e. orientation towards host plants. We also characterised the physiological and morphological properties of antennal lobe neurons of male gynandromorphs. We found that projection neurons with arborisations in the induced female-specific glomeruli showed physiological responses akin to those of female-specific projection neurons in normal females. These results therefore indicate that ORCs confer specific odour tuning to their glomerular targets and, furthermore, instruct odour-specific behaviour.


Asunto(s)
Manduca , Neuronas Receptoras Olfatorias/fisiología , Conducta Sexual Animal/fisiología , Trasplante de Tejidos , Animales , Encéfalo/anatomía & histología , Electrofisiología , Femenino , Masculino , Manduca/anatomía & histología , Manduca/fisiología , Odorantes , Caracteres Sexuales
11.
J Cell Biol ; 123(4): 993-1005, 1993 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8227154

RESUMEN

The integrin family of heterodimeric cell surface receptors play critical roles in multiple biological processes by mediating cellular adhesion to the extracellular matrix (ECM). Adhesion triggers intracellular signaling cascades, including tyrosine phosphorylation and elevation of [Ca2+]i. The Focal Adhesion Kinase (FAK or pp125FAK), a protein tyrosine kinase that colocalizes with integrins in cellular focal adhesions, is a prime candidate for a mediator of integrin signaling events. Here we report an analysis of the domain structure of FAK in which we have identified a contiguous stretch of 159 amino acids within the COOH terminus essential for correct subcellular localization. When placed in the context of an unrelated cytosolic protein, this Focal Adhesion Targeting (FAT) sequence functions to efficiently mediate the focal adhesion localization of this fusion protein. Furthermore, this analysis suggests that pp125FAK cannot be activated oncogenically by mutation. This result could be explained if pp125FK either exhibits a narrow substrate specificity or is diametrically opposed by cellular phosphatases or other cellular processes.


Asunto(s)
Moléculas de Adhesión Celular/metabolismo , Adhesión Celular , Proteínas Tirosina Quinasas/metabolismo , Receptor de Insulina/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular , Células Cultivadas , Embrión de Pollo , Matriz Extracelular/metabolismo , Técnica del Anticuerpo Fluorescente , Quinasa 1 de Adhesión Focal , Proteína-Tirosina Quinasas de Adhesión Focal , Datos de Secuencia Molecular , Fragmentos de Péptidos/metabolismo , Fosforilación , Transducción de Señal , Transfección
12.
J Cell Biol ; 130(5): 1181-7, 1995 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-7657702

RESUMEN

The integrins have recently been implicated in signal transduction. A likely mediator of integrin signaling is focal adhesion kinase (pp125FAK or FAK), a structurally distinct protein tyrosine kinase that becomes enzymatically activated upon engagement of integrins with their ligands. A second candidate signaling molecule is paxillin, a focal adhesion associated, cytoskeletal protein that coordinately becomes phosphorylated on tyrosine upon activation of pp125FAK. Paxillin physically complexes with two protein tyrosine kinases, pp60src and Csk (COOH-terminal src kinase), and the oncoprotein p47gag-crk, each of which could function as part of a paxillin signaling complex. Using an in vitro assay we have established that the cytoplasmic domain of the beta 1 integrin can bind to paxillin and pp125FAK from chicken embryo cell lysates. The NH2-terminal, noncatalytic domain of pp125FAK can bind directly to the cytoplasmic tail of beta 1 and recognizes integrin sequences distinct from those involved in binding to alpha-actinin. Paxillin binding is independent of pp125FAK binding despite the fact that both bind to the same region of beta 1. These results demonstrate that the cytoplasmic domain of the beta subunits of integrins contain binding sites for both signaling molecules and structural proteins suggesting that integrins can coordinate the generation of cytoplasmic signals in addition to their role in anchoring components of the cytoskeleton.


Asunto(s)
Moléculas de Adhesión Celular/metabolismo , Proteínas del Citoesqueleto/metabolismo , Integrinas/metabolismo , Fosfoproteínas/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Receptor de Insulina/metabolismo , Actinina/metabolismo , Secuencia de Aminoácidos , Sitios de Unión/fisiología , Citoplasma/metabolismo , Citoesqueleto/metabolismo , Quinasa 1 de Adhesión Focal , Proteína-Tirosina Quinasas de Adhesión Focal , Datos de Secuencia Molecular , Paxillin , Péptidos/metabolismo , Unión Proteica/fisiología , Transducción de Señal/fisiología
13.
Science ; 174(4008): 490-3, 1971 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-17745741

RESUMEN

The fluidity of a simple liquid is proportional to its degree of expansion over the volume, V(0), at which its molecules are so crowded as to inhibit self-diffusion and viscous (as distinguished from plastic) flow. The equation of proportionality is 1/eta = B[(V - V(0))/V(0)] where eta is the viscosity and V is the molal volume. Values of B are the same for normal paraffins from C(3)H(8) to C(7)H(16) and then decrease progressively as the paraffin lengths increase. Values for other liquids, C(6)H(6), CCl(4), P(4), CS(2), CHCl(3), and Hg, appear to vary with repulsive forces. liquids can be moderately fluid when expanded by less than 10 percent; this shows the unreality of some theoretical treatments of the liquid state. Diffusivity begins from the temperature at which V equals V(0) and can be correlated for temperature dependence, and for solute-solvent interrelations.

14.
Science ; 292(5517): 713-6, 2001 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-11326095

RESUMEN

Shear-wave splitting analysis of local events recorded on land and on the ocean floor in the Tonga arc and Lau backarc indicate a complex pattern of azimuthal anisotropy that cannot be explained by mantle flow coupled to the downgoing plate. These observations suggest that the direction of mantle flow rotates from convergence-parallel in the Fiji plateau to north-south beneath the Lau basin and arc-parallel beneath the Tonga arc. These results correlate with helium isotopes that map mantle flow of the Samoan plume into the Lau basin through an opening tear in the Pacific plate.

15.
J Med Genet ; 44(4): 269-76, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16963482

RESUMEN

BACKGROUND: During whole genome microarray-based comparative genomic hybridisation (array CGH) screening of subjects with idiopathic intellectual disability, we identified two unrelated individuals with a similar de novo interstitial microdeletion at 2p15-2p16.1. Both individuals share a similar clinical phenotype including moderate to severe intellectual disability, autism/autistic features, microcephaly, structural brain anomalies including cortical dysplasia/pachygyria, renal anomalies (multicystic kidney, hydronephrosis), digital camptodactyly, visual impairment, strabismus, neuromotor deficits, communication and attention impairments, and a distinctive pattern of craniofacial features. Dysmorphic craniofacial features include progressive microcephaly, flat occiput, widened inner canthal distance, small palpebral fissures, ptosis, long and straight eyelashes, broad and high nasal root extending to a widened, prominent nasal tip with elongated, smooth philtrum, rounding of the upper vermillion border and everted lower lips. METHODS: Clinical assessments, and cytogenetic, array CGH and fluorescence in situ hybridisation (FISH) analyses were performed. RESULTS: The microdeletions discovered in each individual measured 4.5 Mb and 5.7 Mb, spanning the chromosome 2p region from 57.2 to 61.7 Mb and from 56 to 61.7 Mb, respectively. Each deleted clone in this range demonstrated a dosage reduction from two to one copy in each proband except for clone RP11-79K21, which was present in three copies in each proband and in four copies in their respective parents (two per each chromosome 2 homologue). DISCUSSION: The common constellation of features found in the two affected subjects indicates that they have a newly recognised microdeletion syndrome involving haploinsufficiency of one or more genes deleted within at least a 4.5-Mb segment of the 2p15-16.1 region.


Asunto(s)
Anomalías Múltiples/genética , Trastorno Autístico/genética , Encéfalo/anomalías , Deleción Cromosómica , Trastornos de los Cromosomas/genética , Cromosomas Humanos Par 2/genética , Anomalías Craneofaciales/genética , Riñón/anomalías , Trastorno por Déficit de Atención con Hiperactividad/genética , Niño , Trastornos de los Cromosomas/patología , Cromosomas Humanos Par 2/ultraestructura , Femenino , Humanos , Hibridación Fluorescente in Situ , Recién Nacido , Masculino , Hibridación de Ácido Nucleico , Fenotipo , Síndrome
16.
Nat Neurosci ; 3(9): 927-31, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10966624

RESUMEN

We used neural ensemble recording to examine odor-evoked ensemble patterns in the moth antennal (olfactory) lobe. Different odors are thought to evoke unique spatiotemporal patterns of glomerular activity, but little is known about the population dynamics underlying formation of these patterns. Using a silicon multielectrode array, we observed dynamic network interactions within and between glomeruli. Whereas brief odor pulses repeatedly triggered activity in the same coding ensemble, the temporal pattern of synchronous activity superimposed on the ensemble was neither oscillatory nor odor specific. Rather, synchrony strongly depended on contextual variables such as odor intensity and intermittency. Also, because of emergent inhibitory circuit interactions, odor blends evoked temporal ensemble patterns that could not be predicted from the responses to the individual odorants. Thus even at this early stage of information processing, the timing of odor-evoked neural representations is modulated by key stimulus factors unrelated to the molecular identity of the odor.


Asunto(s)
Manduca/fisiología , Odorantes/análisis , Vías Olfatorias/fisiología , Neuronas Receptoras Olfatorias/fisiología , Receptores Odorantes/fisiología , Potenciales de Acción/fisiología , Animales , Electrofisiología , Manduca/citología , Microelectrodos , Vías Olfatorias/citología , Neuronas Receptoras Olfatorias/citología , Factores de Tiempo
17.
Arthropod Plant Interact ; 12(1): 21-29, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29430259

RESUMEN

Plants have evolved many defenses against insect herbivores, including numerous chemicals that can reduce herbivore growth, performance, and fitness. One group of chemicals, the tropane alkaloids, is commonly found in the nightshade family (Solanaceae) and has been thought to reduce performance and fitness in insects. We examined the effects of the tropane alkaloid scopolamine, the alkaloid constituent of Datura wrightii, which is the most frequent host plant for the abundant and widespread insect herbivore Manduca sexta in the southwestern United States. We exposed caterpillars of two different species to scopolamine: M. sexta, which has a shared evolutionary history with Datura and other solanceous plants, and Galleria mellonella, which does not. We showed that the addition of ecologically-realistic levels of scopolamine to both the diet and the hemolymph of these two caterpillar species (M. sexta and G. mellonella) had no effect on the growth of either species. We also showed that M. sexta has no behavioral preference for or against scopolamine incorporated into an artificial diet. These results are contrary to other work showing marked differences in performance for other insect species when exposed to scopolamine, and provide evidence that scopolamine might not provide the broad-spectrum herbivore resistance typically attributed to it. It also helps to clarify the coevolutionary relationship between M. sexta and one of its main host plants, as well as the physiological mechanism of resistance against scopolamine.

18.
Curr Biol ; 10(15): 877-85, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10959835

RESUMEN

BACKGROUND: The extracellular protein Reln controls neuronal migrations in parts of the cortex, hippocampus and cerebellum. In vivo, absence of Reln correlates with up-regulation of the docking protein Dab1 and decreased Dab1 tyrosine phosphorylation. Loss of the Reln receptor proteins, apolipoprotein receptor 2 and very low density lipoprotein receptor, results in a Reln-like phenotype accompanied by increased Dab1 protein expression. Complete loss of Dab1, however, recapitulates the Reln phenotype. RESULTS: To determine whether Dab1 tyrosine phosphorylation affects Dab1 protein expression and positioning of embryonic neurons, we have identified Dab1 tyrosine phosphorylation sites. We then generated mice in which the Dab1 protein had all the potential tyrosine phosphorylation sites mutated. This mutant protein is not tyrosine phosphorylated during brain development and is not upregulated to the extent observed in the Reln or the apoER2 and VLDLR receptor mutants. Animals expressing the non-phosphorylated Dab1 protein have a phenotype similar to the dab1-null mutant. CONCLUSIONS: Dab1 is downregulated by the Reln signal in neurons in the absence of tyrosine phosphorylation. Dab1 tyrosine phosphorylation sites and not downregulation of Dab1 protein are required for Reln signaling.


Asunto(s)
Encéfalo/crecimiento & desarrollo , Proteínas del Tejido Nervioso/genética , Transducción de Señal , Tirosina/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Encéfalo/anatomía & histología , Encéfalo/metabolismo , Moléculas de Adhesión Celular Neuronal/genética , Moléculas de Adhesión Celular Neuronal/metabolismo , Proteínas de la Matriz Extracelular/genética , Proteínas de la Matriz Extracelular/metabolismo , Regulación del Desarrollo de la Expresión Génica , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Mutantes Neurológicos , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/metabolismo , Fosforilación , Proteína Reelina , Serina Endopeptidasas
19.
Mol Cell Biol ; 16(6): 3169-78, 1996 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8649427

RESUMEN

The integrin family of cell surface receptors mediates cell adhesion to components of the extracellular matrix (ECM). Integrin engagement with the ECM initiates signaling cascades that regulate the organization of the actin-cytoskeleton and changes in gene expression. The Rho subfamily of Ras-related low-molecular-weight GTP-binding proteins and several protein tyrosine kinases have been implicated in mediating various aspects of integrin-dependent alterations in cell homeostasis. Focal adhesion kinase (FAK or pp125FAK) is one of the tyrosine kinases predicted to be a critical component of integrin signaling. To elucidate the mechanisms by which FAK participates in integrin-mediated signaling, we have used expression cloning to identify cDNAs that encode potential FAK-binding proteins. We report here the identification of a cDNA that encodes a new member of the GTPase-activating protein (GAP) family of GTPase regulators. This GAP, termed Graf (for GTPase regulator associated with FAK), binds to the C-terminal domain of FAK in an SH3 domain-dependent manner and preferentially stimulates the GTPase activity of the GTP-binding proteins RhoA and Cdc42. Subcellular localization studies using Graf-transfected chicken embryo cells indicates that Graf colocalizes with actin stress fibers, cortical actin structures, and focal adhesions. Graf mRNA is expressed in a variety of avian tissues and is particularly abundant in embryonic brain and liver. Graf represents the first example of a regulator of the Rho family of small GTP-binding proteins that exhibits binding to a protein tyrosine kinase. We suggest that Graf may function to mediate cross talk between the tyrosine kinases such as FAK and the Rho family GTPase that control steps in integrin-initiated signaling events.


Asunto(s)
Moléculas de Adhesión Celular/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Unión al GTP/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Proteínas/genética , Proteínas/metabolismo , Secuencia de Aminoácidos , Animales , Células Cultivadas , Embrión de Pollo , Clonación Molecular , Quinasa 1 de Adhesión Focal , Proteína-Tirosina Quinasas de Adhesión Focal , Proteínas Activadoras de GTPasa , Datos de Secuencia Molecular , ARN Mensajero/genética , ARN Mensajero/metabolismo , Homología de Secuencia de Aminoácido , Fracciones Subcelulares/metabolismo , Proteína de Unión al GTP cdc42 de Saccharomyces cerevisiae , Proteínas Activadoras de ras GTPasa , Proteína de Unión al GTP rhoA , Dominios Homologos src
20.
Mol Cell Biol ; 17(12): 6906-14, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9372922

RESUMEN

pp125FAK is a tyrosine kinase that appears to regulate the assembly of focal adhesions and thereby promotes cell spreading on the extracellular matrix. In some cells, the C terminus of pp125FAK is expressed as a separate protein, pp41/43FRNK. We have previously shown that overexpression of pp41/43FRNK inhibits tyrosine phosphorylation of pp125FAK and paxillin and, in addition, delays cell spreading and focal adhesion assembly. Thus, pp41/43FRNK functions as a negative inhibitor of adhesion signaling and provides a tool to dissect the mechanism by which pp125FAK promotes cell spreading. We report here that the inhibitory effects of pp41/43FRNK expression can be rescued by the co-overexpression of wild-type pp125FAK and partially rescued by catalytically inactive variants of pp125FAK. However, coexpression of an autophosphorylation site mutant of pp125FAK, which fails to bind the SH2 domain of pp60c-Src, or a mutant that fails to bind paxillin did not promote cell spreading. In contrast, expression of pp41/43FRNK and pp60c-Src reconstituted cell spreading and tyrosine phosphorylation of paxillin but did so without inducing tyrosine phosphorylation of pp125FAK. These data provide additional support for a model whereby pp125FAK acts as a "switchable adaptor" that recruits pp60c-Src to phosphorylate paxillin, promoting cell spreading. In addition, these data point to tyrosine phosphorylation of paxillin as being a critical step in focal adhesion assembly.


Asunto(s)
Moléculas de Adhesión Celular/fisiología , Adhesión Celular/fisiología , Movimiento Celular/fisiología , Proteínas del Citoesqueleto/metabolismo , Fosfoproteínas/metabolismo , Proteínas Tirosina Quinasas/fisiología , Animales , Sitios de Unión , Moléculas de Adhesión Celular/química , Moléculas de Adhesión Celular/genética , Células Cultivadas , Embrión de Pollo , Quinasa 1 de Adhesión Focal , Proteína-Tirosina Quinasas de Adhesión Focal , Expresión Génica , Modelos Biológicos , Mutación , Paxillin , Fosforilación , Proteínas Tirosina Quinasas/química , Proteínas Tirosina Quinasas/genética , Proteínas Proto-Oncogénicas pp60(c-src)/genética , Transducción de Señal , Tirosina/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA