RESUMEN
Colfax, Louisiana hosts a commercial hazardous waste thermal treatment (TT) facility, which treats fireworks, explosives, and military ordnances by open-burn/open-detonation one mile from the edge of the nearest community. Seventy-one percent of Colfax's residents are Black, and forty-six percent live below poverty, indicating the community's structural vulnerability. This community-based study originated at the behest of Colfax community members. We hypothesized that the close relationships among members of this enclave may have enhanced the community's ability to mobilize in opposition to the TT facility. We conducted semi-structured oral history interviews with nineteen community members and examined the social and interorganizational networks used by the Colfax community to claim its role in decision-making regarding the TT facility after years of exclusion from this process. Interview transcripts were analyzed through the lens of community capacity theory to gain insight into how interactions among community members about the environmental hazards led to social mobilization and improved participation in the decision-making process using codes for communication, organization, and outcome. Additionally, we reviewed Louisiana Department of Environmental Quality records for complaints about the facility to gauge public participation. One notable theme across several interviews was exclusion from the initial decision-making process related to the facility. However, interviewees noted a sustained effort was made among community members to educate themselves about the facility, organize a response through neighbor-to-neighbor contact, and take action by submitting formal complaints and participating in public hearings. Through the lens of environmental justice, this study illustrates an evolving condition of procedural justice.
RESUMEN
NPM1 is a multifunctional nucleolar protein implicated in several processes such as ribosome maturation and export, DNA damage response and apoptotic response to stress stimuli. The NPM1 gene is involved in human tumorigenesis and is found mutated in one third of acute myeloid leukemia patients, leading to the aberrant cytoplasmic localization of NPM1. Recent studies indicated that the N6L multivalent pseudopeptide, a synthetic ligand of cell-surface nucleolin, is also able to bind NPM1 with high affinity. N6L inhibits cell growth with different mechanisms and represents a good candidate as a novel anticancer drug for a number of malignancies of different histological origin. In this study we investigated whether N6L treatment could drive antitumor effect in acute myeloid leukemia cell lines. We found that N6L binds NPM1 at the N-terminal domain, co-localizes with cytoplasmic, mutated NPM1, and interferes with its protein-protein associations. N6L toxicity appears to be p53 dependent but interestingly, the leukemic cell line harbouring the mutated form of NPM1 is more resistant to treatment, suggesting that NPM1 cytoplasmic delocalization confers protection from p53 activation. Moreover, we show that N6L sensitizes AML cells to doxorubicin and cytarabine treatment. These studies suggest that N6L may be a promising option in combination therapies for acute myeloid leukemia treatment.
Asunto(s)
Leucemia Mieloide Aguda/tratamiento farmacológico , Proteínas Nucleares/fisiología , Péptidos/farmacología , Línea Celular Tumoral , Citarabina/farmacología , Doxorrubicina/farmacología , Humanos , Mutación , Proteínas Nucleares/análisis , Proteínas Nucleares/genética , Nucleofosmina , Proteína p53 Supresora de Tumor/fisiologíaRESUMEN
LIM kinase 1 (LIMK1) and LIM kinase 2 (LIMK2) regulate actin dynamics by phosphorylating cofilin. In this review, we outline studies that have shown an involvement of LIMKs in neuronal function and we detail some of the pathways and molecular mechanisms involving LIMKs in neurodevelopment and synaptic plasticity. We also review the involvement of LIMKs in neuronal diseases and emphasize the differences in the regulation of LIMKs expression and mode of action. We finally present the existence of a cofilin-independent pathway also involved in neuronal function. A better understanding of the differences between both LIMKs and of the precise molecular mechanisms involved in their mode of action and regulation is now required to improve our understanding of the physiopathology of the neuronal diseases associated with LIMKs.
Asunto(s)
Enfermedades del Sistema Nervioso Central/enzimología , Enfermedades del Sistema Nervioso Central/fisiopatología , Sistema Nervioso Central/enzimología , Sistema Nervioso Central/fisiología , Quinasas Lim/metabolismo , Animales , Sistema Nervioso Central/citología , Sistema Nervioso Central/fisiopatología , Enfermedades del Sistema Nervioso Central/patología , Humanos , Neuronas/enzimologíaRESUMEN
Extracellular matrix metalloproteinase inducer (EMMPRIN), known for its ability to induce matrix metalloproteinase (MMP) expression, was proposed to play a role in the adverse cardiac extracellular matrix remodeling. After observing an age-associated increase in cardiac EMMPRIN expression in both mice and rats, the role and mechanism of action of EMMPRIN was investigated in the myocardial age-associated changes using 3, 12 and 24 month old EMMPRIN knock-out (KO) vs. wild-type (WT) mice, by cardiac echocardiography, Western blots, immunohistochemistry, ELISA and histology. Adilated cardiomyopathy characterized by a decreased ejection fraction and an enlargement of left ventricular chamber (LV) associated with LV hypertrophy, occurred in KO mice as soon as 12 month old. The increase in interstitial collagen deposition during aging in WT mice could not be detected in KO mice. This may be related to the reduced activation (48% reduction; P < 0.05) and signaling (smad2/3 nuclear translocation) of TGF-ß in the 12 month old KO mice which paralleled with a greater reduction in the TGF-ß known activating enzymes such as MT1-MMP and MMP-1 (33% and 37% reduction respectively, between 3 and 12 month old in KO mice; P < 0.05) as well as uPA. These findings demonstrate that EMMPRIN gene silencing is associated with an aberrant extracellular matrix remodeling, characterized by the absence of a detected age-associated fibrosis and consequently to dilated cardiopathy, indicating that a fine regulation of EMMPRIN is essential for the coordinated ECM remodeling during aging.
Asunto(s)
Envejecimiento/fisiología , Basigina/metabolismo , Matriz Extracelular/metabolismo , Remodelación Ventricular/fisiología , Animales , Basigina/genética , Colágeno/metabolismo , Femenino , Masculino , Metaloproteinasas de la Matriz/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Miocardio/metabolismo , Ratas , Ratas WistarRESUMEN
OBJECTIVE: The natural history of pineal cysts still remains unclear. Incidental pineal cysts have become more common which raises the question of their management. Symptomatic pineal cysts may require a surgical solution but therapeutic indications have not yet been clearly established. METHOD: From 1986 to 2012, 26 patients with pineal cysts were identified. Their medical records were retrospectively assessed focusing on the initial symptoms, imaging characteristics of the cyst, management strategy, operative technique and their complications, as well as the latest follow-up. A systematic review of the literature is also presented. RESULTS: Twenty-six patients with pineal cysts were identified. The mean age was 23.5 years ranging from 7 to 49 years. Symptoms included intracranial hypertension with obstructive hydrocephalus in 18 cases and oculomotor anomalies in 12 cases. Two adult cases presented with non-specific headaches and did not require surgery. Twenty patients were operated via a suboccipital transtentorial approach with total removal of the cyst in 70% of the cases, while the remaining 4 cases were treated with an intraventricular endoscopic marsupialization associating a third ventriculostomy. Four patients required a preoperative ventriculo-peritoneal shunt due to life-threatening obstructive hydrocephalus. Overall, peri-operative mortality was nil. In the two non-operated patients, the cyst remained stable and no recurrences were observed in all operated patients with a mean follow-up of 144 months. CONCLUSION: In the majority of incidental pineal cysts, a clinical and imaging follow-up is sufficient but occasionally not required especially in adults as very rare cases of increase in size have been reported.
Asunto(s)
Neoplasias Encefálicas/cirugía , Quistes del Sistema Nervioso Central/cirugía , Hidrocefalia/cirugía , Recurrencia Local de Neoplasia/cirugía , Derivación Ventriculoperitoneal , Humanos , Derivación Ventriculoperitoneal/métodos , Ventriculostomía/métodosRESUMEN
INTRODUCTION: Pulmonary metastases from meningioma are rare and present with specific clinical and radiological features. The diagnostic and therapeutic management of metastatic meningioma illustrate the concept of orphan thoracic oncology. CASE REPORT: We report the case of a 58-year-old male, former smoker, with a previous history of atypical meningioma and resected lung adenocarcinoma. During oncologic surveillance, a computed-tomography scan disclosed multiple well-defined homogeneous nodules in the right lung. These nodules were hypermetabolic at positron-emission tomography with fluorodesoxyglucose. Pathological examination of metastasectomy specimens revealed metastatic malignant meningioma. CONCLUSIONS: Pulmonary metastases may occur in malignant meningioma. Twenty-one cases have been reported over the past 20 years. As for all rare tumours, multidisciplinary consensus is mandatory, in the absence of evidence-based recommendations based on prospective trials or observational studies.
Asunto(s)
Neoplasias Pulmonares/secundario , Neoplasias Meníngeas/patología , Meningioma/secundario , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/terapia , Masculino , Meningioma/diagnóstico , Meningioma/terapia , Persona de Mediana EdadRESUMEN
BACKGROUND: Wegener granulomatosis (WG) is an uncommon systemic necrotizing vasculitis that demonstrates renal and respiratory tropism. While the pathogenesis of WG remains controversial, autoimmune and inflammatory mechanisms are likely to be involved. The nervous system could be affected in up to 54% of cases. Although central nervous system involvement has been reported in 7-11% of cases, aneurysmal subarachnoid hemorrhage (SAH) occurrence is exceptional. METHODS: We describe the third reported case of WG-related aneurysmal SAH and then discuss the diagnosis and pathogenesis of WG along with the physiopathology of intracranial aneurysm in light of recent data reported in the literature. RESULTS: A 63-year-old woman with WG was referred to our neurosurgical department for aneurysmal SAH. The vasculitis diagnosis had been established 4 years earlier when she presented with chronic sinusitis, recurrent cystitis, and renal failure. The cerebral angiography revealed an anterior communicating artery dysplastic aneurysm. The neurosurgical management of the aneurysm was scheduled but delayed because the patient was experiencing a vasculitis flare-up. Immunosuppressive therapy and intravenous corticotherapy were given, with the patient's improvement, allowing neurosurgical clipping of the aneurysm. CONCLUSIONS: Wegener granulomatosis-related aneurysmal SAH is an exceptional condition in neurovascular pathology. As inflammatory mechanisms are involved in the pathogenesis of aneurysm, the vasculitis flare-up could account for this SAH. The management of WG could benefit from anti-inflammatory therapy, as could the vasculitis-related SAH. SAH occurrence in patients with systemic vasculitis could indicate a vasculitis flare-up.
Asunto(s)
Granulomatosis con Poliangitis/complicaciones , Hemorragia Subaracnoidea/complicaciones , Corticoesteroides/uso terapéutico , Antiinflamatorios/uso terapéutico , Encéfalo/patología , Angiografía Cerebral , Femenino , Granulomatosis con Poliangitis/tratamiento farmacológico , Granulomatosis con Poliangitis/patología , Humanos , Inmunosupresores/uso terapéutico , Angiografía por Resonancia Magnética , Persona de Mediana Edad , Diálisis Peritoneal , Hemorragia Subaracnoidea/patología , Hemorragia Subaracnoidea/cirugía , Tomografía Computarizada por Rayos X , Vasculitis/etiologíaRESUMEN
The process of visuo-spatial updating is crucial in guiding human behaviour. While the parietal cortex has long been considered a principal candidate for performing spatial transformations, the exact underlying mechanisms are still unclear. In this study, we investigated in a patient with a right occipito-parietal lesion the ability to update the visual space during vestibularly guided saccades. To quantify the possible deficits in visual and vestibular memory processes, we studied the subject's performance in two separate memory tasks, visual (VIS) and vestibular (VES). In the VIS task, a saccade was elicited from a central fixation point to the location of a visual memorized target and in the VEST task, the saccade was elicited after whole-body rotation to the starting position thus compensating for the rotation. Finally, in an updating task (UPD), the subject had to memorize the position of a visual target then after a whole-body rotation he had to produce a saccade to the remembered visual target location in space. Our main findings was a significant hypometria in the final eye position of both VEST and UPD saccades induced during rotation to the left (contralesional) hemispace as compared to saccades induced after right (ipsilesional) rotation. Moreover, these deficits in vestibularly guided saccades correlated with deficits in vestibulo-ocular time constant, reflecting disorders in the inertial vestibular integration path. We conclude that the occipito-parietal cortex in man can provide a first stage in visuo-spatial remapping by encoding inertial head position signals during gaze orientation.
Asunto(s)
Corteza Cerebral/fisiología , Percepción Espacial/fisiología , Vestíbulo del Laberinto/fisiología , Percepción Visual/fisiología , Adulto , Fijación Ocular/fisiología , Lateralidad Funcional/fisiología , Movimientos de la Cabeza/fisiología , Humanos , Malformaciones Arteriovenosas Intracraneales/complicaciones , Malformaciones Arteriovenosas Intracraneales/cirugía , Masculino , Memoria/fisiología , Lóbulo Occipital/lesiones , Lóbulo Parietal/patología , Estimulación Luminosa , Rotación , Movimientos Sacádicos/fisiología , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/psicología , Accidente Cerebrovascular/cirugíaRESUMEN
OBJECTIVES: To correlate changes of cranial vault measurements of an adult population during the aging process with brain size using the maximum width of the third ventricle in the axial AC-PC plane. MATERIALS AND METHODS: Prospective study of 126 adult subjects (range: 20 to 80 years) with normal brain MRI and without history of neuropsychiatric disorder. MEASUREMENTS INCLUDED: Cranial vault (Maximum length: Glabella-Opisthocranion, Maximum width: euryon-euryon, and maximum height: Basion-Vertex) measurements and maximum width of the third ventricle in the A C-PC plane. RESULTS: Vault measurements (length, width, high) were similar for every age group, irrespective of gender. The variability of cranial vault measurements between individuals was low (<1 cm). Cranial vault measurements were larger for men, but this was not significant when adjusted for body height Comparatively, a gradual widening of the third ventricle, with an exponential behavior, was observed with advancing age. CONCLUSION: Our results indicate that cranial vault measurements are stable over time (between 20-80 years) comparatively to brain atrophy with advancing age. The low variability of cranial vault measurements and their stability over time should be taken into account during segmentation and normalization of brain parenchymal structures.
Asunto(s)
Envejecimiento/fisiología , Encéfalo/anatomía & histología , Encéfalo/fisiología , Cráneo/anatomía & histología , Cráneo/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Cefalometría , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Valores de ReferenciaRESUMEN
The value of exotic germplasm in broadening the genetic base of most crops has been demonstrated many times. However, the difficulties involved in working with exotic germplasm have limited their utility in plant breeding. Unwanted linkages often thwart the successful incorporation of beneficial exotic genes into commercial lines. Thus, the use of exotics in traditional breeding makes the process of crop improvement a tedious, time-consuming and expensive endeavor. The availability of molecular markers makes it possible to isolate specific genomic regions and transfer them into commercial varieties with minimal linkage drag. We found a yield-enhancing quantitative trait locus (QTL) from Glycine soja (Siebold and Zucc.) by evaluating a population of 265 BC(2) individuals from a cross between HS-1 and PI 407305. The yield QTL was located on linkage group B2(U26) of the soybean [Glycine max (L.) Merrill] genetic linkage map. In a 2-year, multi-location study, individuals carrying the PI 407305 haplotype at the QTL locus demonstrated a 9.4% yield advantage over individuals that did not contain the exotic haplotype. When tested in a more uniform "HS-1-like" background in two locations, we observed an 8% yield advantage for lines that carry the PI 407305 haplotype. We further assessed the QTL effect in various elite soybean genetic backgrounds. The yield effect was consistently observed in only two of six genetic backgrounds. Individuals carrying the PI 407305 haplotype at the QTL locus had a 9% yield advantage in yield trials across locations. Despite the limited adaptability of this yield-QTL across genetic backgrounds, this study demonstrates the potential of exotic germplasm for yield enhancement in soybean.
Asunto(s)
Genes de Plantas , Glycine max/genética , Sitios de Carácter Cuantitativo , Alelos , Mapeo Cromosómico , Cruzamientos Genéticos , ADN/metabolismo , Ligamiento Genético , Marcadores Genéticos , Variación Genética , HaplotiposRESUMEN
Recently, it has been shown that mammalian PEBPs are implicated in several signalling pathways controlling the cellular cycle. In particular, during brain development, the N-terminal part of mammalian PEBP is specifically cleaved and the resulting 11 amino acid peptide stimulates the growth and activity of acetylcholinergic neurons. The crystallographic structure of bovine and human PEBPs has revealed that their N- and C-terminal parts are accessible and exposed to the solvent suggesting that they may be involved in specific interactions with cellular partners. We have chemically synthetized the two peptides corresponding to these terminal parts and studied their structure in solution by circular dichroism and NMR spectroscopies: both of them are well-structured. The N-terminal peptide is composed of a series of turns, leading to a hook conformation. The C-terminal peptide displays a globally helical conformation similar to that observed in the whole protein; it is characterized by an amphipatic feature with a hydrophobic cluster located on one side. These structural features enlighten previous fluorescence and monolayer experiments and give new insights on the roles of both PEBP termini.
Asunto(s)
Proteína de Unión a Andrógenos , Proteínas Portadoras/química , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Soluciones/química , Secuencia de Aminoácidos , Animales , Bovinos , Dicroismo Circular , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Datos de Secuencia Molecular , Proteínas de Unión a Fosfatidiletanolamina , Proteínas de Transferencia de Fosfolípidos , Mapeo de Interacción de Proteínas , Homología de SecuenciaRESUMEN
Lag1p and Lac1p are two homologous transmembrane proteins of the endoplasmic reticulum in Saccharomyces cerevisiae. Homologous genes have been found in a wide variety of eukaryotes. In yeast, both genes, LAC1 and LAG1, are required for efficient endoplasmic reticulum-to-Golgi transport of glycosylphosphatidylinositol-anchored proteins. In this study, we show that lag1 Delta lac1 Delta cells have reduced sphingolipid levels due to a block of the fumonisin B1-sensitive and acyl-CoA-dependent ceramide synthase reaction. The sphingolipid synthesis defect in lag1 Delta lac1 Delta cells can be partially corrected by overexpression of YPC1 or YDC1, encoding ceramidases that have been reported to have acyl-CoA-independent ceramide synthesis activity. Quadruple mutant cells (lag1 Delta lac1 Delta ypc1 Delta ydc1 Delta) do not make any sphingolipids, but are still viable probably because they produce novel lipids. Moreover, lag1 Delta lac1 Delta cells are resistant to aureobasidin A, an inhibitor of the inositolphosphorylceramide synthase, suggesting that aureobasidin A may be toxic because it leads to increased ceramide levels. Based on these data, LAG1 and LAC1 are the first genes to be identified that are required for the fumonisin B1-sensitive and acyl-CoA-dependent ceramide synthase reaction.
Asunto(s)
Acilcoenzima A/metabolismo , Fumonisinas , Proteínas Fúngicas/metabolismo , Proteínas de la Membrana/metabolismo , Oxidorreductasas/metabolismo , Proteínas de Saccharomyces cerevisiae , Esfingolípidos/metabolismo , Amidohidrolasas/genética , Amidohidrolasas/metabolismo , Ácidos Carboxílicos/farmacología , Ceramidasas , Ceramidas/biosíntesis , Inhibidores Enzimáticos/farmacología , Proteínas Fúngicas/genética , Proteínas de la Membrana/genética , Mutagénesis , Oxidorreductasas/antagonistas & inhibidores , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genéticaRESUMEN
The ability of phosphatidylethanolamine-binding protein (PEBP) to bind membranes was tested by using small and large unilamellar vesicles and monolayers composed of l-alpha-1,2-dimyristoylphosphatidylcholine, l-alpha-1,2-dimyristoylphosphatidylglycerol and l-alpha-1,2-dimyristoylphosphatidylethanolamine. PEBP only bound to model membranes containing l-alpha-1,2-dimyristoylphosphatidylglycerol; the interaction was primarily due to electrostatic forces between the basic protein and the acidic phospholipids. Further experiments indicated that the interaction was not dependent on the length and unsaturation of the phospholipid acyl chains and was not modified by the presence of cholesterol in the membrane. PEBP affinity for negatively charged membranes is puzzling considering the previous identification of the protein as a phosphatidylethanolamine-binding protein, and suggests that the association of PEBP with phospholipid membranes is driven by a mechanism other than its binding to solubilized phosphatidylethanolamine. An explanation was suggested by its three-dimensional structure: a small cavity at the protein surface has been reported to be the binding site of the polar head of phosphatidylethanolamine, while the N-terminal and C-terminal parts of PEBP, exposed at the protein surface, appear to be involved in the interaction with membranes. To test this hypothesis, we synthesized the two PEBP terminal regions and tested them with model membranes in parallel with the whole protein. Both peptides displayed the same behaviour as whole PEBP, indicating that they could participate in the binding of PEBP to membranes. Our results strongly suggest that PEBP directly interacts with negatively charged membrane microdomains in living cells.
Asunto(s)
Proteína de Unión a Andrógenos , Proteínas Portadoras/metabolismo , Membranas Artificiales , Secuencia de Aminoácidos , Animales , Proteínas Portadoras/química , Bovinos , Dicroismo Circular , Técnicas In Vitro , Modelos Moleculares , Datos de Secuencia Molecular , Proteínas de Transferencia de Fosfolípidos , Espectrometría de FluorescenciaRESUMEN
The isolation of thionein (T) from tissues has not been reported heretofore. T contains 20 cysteinyl residues that react with 7-fluorobenz-2-oxa-1,3-diazole-4-sulfonamide to form fluorescent adducts. In metallothionein (MT) the cysteinyl residues, which are bound to zinc, do not react. However, they do react in the presence of a chelating agent such as EDTA. The resultant difference in chemical reactivity provides a means to measure T in the absence of EDTA, (MT + T) in its presence, and, of course, MT by difference. The 7-fluorobenz-2-oxa-1,3-diazole-4-sulfonamide derivative of T can be isolated from tissue homogenates by HPLC and quantified fluorimetrically with a detection limit in the femtomolar range and a linear response over 3 orders of magnitude. Analysis of liver, kidney, and brain of rats reveals almost as much T as MT. Moreover, in contrast to earlier views, MT in tissue extracts appears to be less stable than T. The existence of T in tissues under normal physiological conditions has important implications for its function both in zinc metabolism and the redox balance of the cell.
Asunto(s)
Cisteína/química , Metalotioneína/metabolismo , Animales , Encéfalo/metabolismo , Cromatografía Líquida de Alta Presión , Colorantes Fluorescentes , Riñón/metabolismo , Hígado/metabolismo , Metalotioneína/química , RatasRESUMEN
Metallothionein (MT) localizes in the intermembrane space of liver mitochondria as well as in the cytosol and nucleus. Incubation of intact liver mitochondria with physiological, micromolar concentrations of MT leads to the import of MT into the mitochondria where it inhibits respiration. This activity is caused by the N-terminal beta-domain of MT; in this system, the isolated C-terminal alpha-domain is inactive. Free zinc inhibits respiration at concentrations commensurate with the zinc content of either MT or the isolated beta-domain, indicating that MT inhibition involves zinc delivery to mitochondria. Respiratory inhibition of uncoupled mitochondria identifies the electron transfer chain as the primary site of inhibition. The apoform of MT, thionein, is an endogenous chelating agent and activates zinc-inhibited respiration with a 1:1 stoichiometry ([zinc binding sites]/[zinc]). Carbamoylation of the lysines of MT significantly attenuates the inhibitory effect, suggesting that these residues are critical for the passage of MT through the outer mitochondrial membrane. Such an import pathway has been proposed for other proteins that also lack a mitochondrial targeting sequence, e.g., apocytochrome c, and possibly Cox17, a mitochondrial copper chaperone that is the only protein known so far to exhibit significant primary sequence homology to MT. The presence and respiratory inhibition of MT in liver, but not heart, mitochondria suggest a hitherto unknown biological modulating activity of MT in cellular respiration and energy metabolism in a tissue-specific manner.
Asunto(s)
Transporte de Electrón , Metalotioneína/metabolismo , Mitocondrias Cardíacas/metabolismo , Mitocondrias Cardíacas/fisiología , Mitocondrias Hepáticas/metabolismo , Mitocondrias Hepáticas/fisiología , Animales , Lisina/metabolismo , Masculino , Metalotioneína/antagonistas & inhibidores , Metalotioneína/química , Transporte de Proteínas , Ratas , Ratas WistarRESUMEN
A differential pancreatic behavior observed between male and female mice in diabetes and pancreatitis led us to study the gene and protein expressions of endocrine and exocrine pancreatic proteins in normal mice. We compared the levels of expression of six pancreatic genes and of four of the corresponding proteins in male and female mice OF1. Amylase gene expression was found to be significantly higher in females than in males, whereas trypsinogen and lipase gene expression were significantly lower. For chymotrypsinogen, reg, and insulin the differences were not significant. This sexual dimorphism did not exist in rat pancreas, where no gender difference was observed. After characterization of mice enzymes by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and antibodies directed to the closely related human pancreatic enzymes, we have compared the levels of these proteins in mice pancreatic homogenates. No significant difference was observed between males and females at the level of protein expression. These data suggest a hormonal sexual difference in the regulation of pancreatic protein synthesis at the pre- and posttranscriptional levels in normal mice, which may play a role in the development of mice pancreatic diseases.
Asunto(s)
Regulación de la Expresión Génica , Páncreas/metabolismo , Amilasas/genética , Animales , Quimotripsinógeno/genética , Femenino , Lipasa/genética , Masculino , Ratones , ARN Mensajero/análisis , Ratas , Caracteres Sexuales , Tripsinógeno/genéticaRESUMEN
The alpha- and beta-polypeptides of human metallothionein (isoform 2), obtained by chemical synthesis, were converted into their respective zinc/thiolate clusters, and each domain was investigated separately. Proton titration data for the N-terminal beta-domain fit a simple model with three ionizations of the same apparent pK(a) value of 4.9 and a collective binding constant for zinc of 5 x 10(-12) M at pH 7.0. The zinc cluster in the C-terminal alpha-domain is more stable than that in the beta-domain. Its pH titration is also more complex, indicating at least two classes of zinc sites with different affinities. The whole molecule is stabilized with regard to the individual domains. Chemical modification implicates lysine side chains in both the stabilization of the beta-domain cluster and the mutual stabilization of the domains in the whole molecule. The two zinc clusters also differ in the reactivity of their cysteine sulfurs and their potential to donate zinc to an acceptor molecule dependent on its type and characteristics. The isolated beta-domain cluster reacts faster with Ellman's reagent and is a better zinc donor toward zinc-depleted sorbitol dehydrogenase than is the isolated alpha-domain cluster, whereas the reverse is observed when a chelating agent is the zinc acceptor. Thus, although each cluster assembles independently of the other, the cumulative properties of the individual domains do not suffice to describe metallothionein either structurally or functionally. The two-domain structure of the whole molecule is important for its interaction with ligands and for control of its reactivity and overall conformation.