RESUMEN
Freshwater fish in several regions of New York State (NYS) are known to contain concentrations of mercury (Hg) associated with negative health effects in wildlife and humans. We collected blood and breast feathers from bald eagle (Haliaeetus leucocephalus) nestlings throughout NYS, with an emphasis on the Catskill region to determine their exposure to Hg. We assessed whether habitat type (lake or river), region (Delaware-Catskill region vs. rest of NY) or sample site elevation influenced Hg concentrations in bald eagle breast feathers using ANCOVA. The model was significant and accounted for 41% of the variability in log10 breast feather Hg concentrations. Mercury concentrations in nestling breast feathers were significantly greater in the Delaware-Catskill Region (geometric mean: 14.5 µg/g dw) than in the rest of NY (7.4 µg/g, dw), and greater at nests located at higher elevations. Habitat type (river vs. lake) did not have a significant influence on breast feather Hg concentrations. Geometric mean blood Hg concentrations were significantly greater in Catskill nestlings (0.78 µg/g ww) than in those from the rest of NY (0.32 µg/g). Mercury concentrations in nestling breast feathers and especially blood samples from the Delaware-Catskill region were generally greater than those reported for most populations sampled elsewhere, including areas associated with significant Hg pollution problems. Bald eagles can serve as valuable Hg bioindicators in aquatic ecosystems of NYS, particularly given their broad statewide distribution and their tendency to nest across all major watersheds and different habitat types.
Asunto(s)
Águilas , Monitoreo del Ambiente , Contaminantes Ambientales/análisis , Mercurio/análisis , Animales , Ecosistema , Plumas/química , New YorkRESUMEN
Mercury (Hg) pollution is an environmental problem that adversely affects human and ecosystem health at local, regional, and global scales-including within New York State. More than two-thirds of the Hg currently released to the environment originates, either directly or indirectly, from human activities. Since the early 1800s, global atmospheric Hg concentrations have increased by three- to eight-fold over natural levels. In the U.S., atmospheric emissions and point-source releases to waterways increased following industrialization into the mid-1980s. Since then, water discharges have largely been curtailed. As a result, Hg emissions, atmospheric concentrations, and deposition over the past few decades have declined across the eastern U.S. Despite these decreases, Hg pollution persists. To inform policy efforts and to advance public understanding, the New York State Energy Research and Development Authority (NYSERDA) sponsored a scientific synthesis of information on Hg in New York State. This effort includes 23 papers focused on Hg in atmospheric deposition, water, fish, and wildlife published in Ecotoxicology. New York State experiences Hg contamination largely due to atmospheric deposition. Some landscapes are inherently sensitive to Hg inputs driven by the transport of inorganic Hg to zones of methylation, the conversion of inorganic Hg to methylmercury, and the bioaccumulation and biomagnification along food webs. Mercury concentrations exceed human and ecological risk thresholds in many areas of New York State, particularly the Adirondacks, Catskills, and parts of Long Island. Mercury concentrations in some biota have declined in the Eastern Great Lakes Lowlands and the Northeastern Highlands over the last four decades, concurrent with decreases in water releases and air emissions from regional and U.S. sources. However, widespread changes have not occurred in other ecoregions of New York State. While the timing and magnitude of the response of Hg levels in biota varies, policies expected to further diminish Hg emissions should continue to decrease Hg concentrations in food webs, yielding benefits to the fish, wildlife, and people of New York State. Anticipated improvements in the Hg status of aquatic ecosystems are likely to be greatest for inland surface waters and should be roughly proportional to declines in atmospheric Hg deposition. Efforts that advance recovery from Hg pollution in recent years have yielded significant progress, but Hg remains a pollutant of concern. Indeed, due to this extensive compilation of Hg observations in biota, it appears that the extent and intensity of the contamination on the New York landscape and waterscape is greater than previously recognized. Understanding the extent of Hg contamination and recovery following decreases in atmospheric Hg deposition will require further study, underscoring the need to continue existing monitoring efforts.
Asunto(s)
Monitoreo del Ambiente , Contaminación Ambiental/estadística & datos numéricos , Mercurio/análisis , Contaminantes Ambientales/análisis , Humanos , Lagos , Compuestos de Metilmercurio , New YorkRESUMEN
The Natural Resource Damage Assessment and Restoration Trustees for the Deepwater Horizon oil spill assessed the external oiling of migratory bird species dependent on open water in the Gulf of Mexico following the aforementioned spill. The assessment was designed to evaluate birds that use open water during the winter within 40 km of the Gulf shoreline. We focused on the American white pelican (Pelecanus erythrorhynchos), common loon (Gavia immer), and northern gannet (Morus bassanus). Point counts (pelican, loon) or strip transects (gannet) were used and each target species was assessed for oiling (unoiled, trace, light, moderate, or heavy amounts) and photographed. Due to distance at sighting and/or poor visibility, not all visible birds were assessed. The percentage of birds oiled varied by species, with the common loon being the highest (23.6%), followed by American white pelican (16.9%), and northern gannet (6.9%). Most of the American white pelicans and common loons had trace (83% and 72%, respectively) or light levels (11% and 24%, respectively) of oiling. The northern gannet had just trace levels of oiling. Some pelicans (6%) and loons (4%) had moderate amounts of oiling. Based on expert derived-mortality estimates and our estimates of oil exposure, we used Monte Carlo simulations to predict expected decreases of 2.5%, 4%, and 11% in the observed population for the northern gannet, American white pelican, and common loon, respectively. While these values are underestimates of the true values given the long time lag (10-12 months) between the oil spill and the assessment, these data represent some of the few estimates of exposure for these species and describe minimum risk estimates to these species.
Asunto(s)
Aves , Contaminación por Petróleo , Contaminantes Químicos del Agua , Animales , Monitoreo del Ambiente , Golfo de México , Estaciones del Año , Contaminantes Químicos del Agua/toxicidadRESUMEN
Clonality assessment by the detection of immunoglobulin (IG) gene rearrangements is an important method to determine whether two concurrent or subsequent lymphoid malignancies in one patient are clonally related. Here, we report the detailed clonality analysis in a patient with a diagnosis of B-cell acute lymphoblastic leukemia (B-ALL) followed by a histiocytic sarcoma (HS), in which we were able to study clonal evolution by applying next generation sequencing (NGS) to identify IG rearrangements and gene mutations. Using the sequence information of the NGS-based IG clonality analysis, multiple related subclones could be distinguished in the PAX5 P80R-mutated B-ALL. Notably, only one of these subclones evolved into HS after acquiring a RAF1 mutation. This case demonstrates that NGS-based IG clonality assessment and mutation analysis provide clear added value for clonal comparison and thereby improves clinicobiological understanding.
Asunto(s)
Linfoma de Burkitt , Sarcoma Histiocítico , Leucemia-Linfoma Linfoblástico de Células Precursoras , Humanos , Sarcoma Histiocítico/genética , Sarcoma Histiocítico/patología , Inmunoglobulinas/genética , Reordenamiento Génico , Linfoma de Burkitt/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Factor de Transcripción PAX5/genéticaRESUMEN
Potato can suffer from several abiotic stresses such as cold temperature, high soil salinity, lack of water or heavy metal exposure, to name a few. They are known to affect plant growth as well as productivity, with differential regulations at several levels. Potato response to cold and salt exposure was investigated at both transcriptomic and proteomic levels in a growth chamber experiment. Cold exposure in potato resulted in a higher number of significantly differentially regulated genes compared to salt exposure, whereas there were nearly three times more differentially regulated proteins after salt exposure when compared to cold exposure. The allocation of up and down-regulated genes at the functional category level also differed between salt and cold exposure although common trends, previously described in various abiotic stresses, were observed. In both stresses, the majority of photosynthesis-related genes were down-regulated whereas cell rescue and transcription factor-related genes were mostly up-regulated. In the other functional categories no common trend was observed; salt exposure results displayed a strong down-regulation of genes implicated in primary metabolism, detoxication apparatus and signal transduction, whereas upon cold exposure, up and down-regulated genes were similar in number. At the proteomic level, the abundance of the majority of identified proteins was increased except for the photosynthesis-related proteins, which were mostly less abundant after both salt and cold exposure. Common responses between salt and cold stress and specific responses inherent to these abiotic stresses are described.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/metabolismo , Solanum tuberosum/fisiología , Estrés Fisiológico , Frío , Perfilación de la Expresión Génica , Genes de Plantas , Análisis de Secuencia por Matrices de Oligonucleótidos , Proteínas de Plantas/genética , Proteómica , Tolerancia a la Sal , Solanum tuberosum/genéticaRESUMEN
Due to its reproducibility and sensitivity, real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) has become the method of choice for quantifying gene expression. However, the accuracy of RT-qPCR is prone to bias if proper precautions are not taken, e.g. starting with intact, non-degraded RNA, considering the PCR efficiency and using the right reference gene(s) for normalization. It has been reported that some of the well-known reference genes are differentially regulated under certain experimental conditions suggesting that there is no gene that could be used as a universal reference. This paper aims at selecting the most suitable reference gene(s) out of six putative genes to be used as normalizer(s) for quantification of gene expression in the grapevine-downy mildew interaction as well as upon induced resistance with chemical elicitors. Moreover, the paper aims at determining the optimal number of reference genes to be used in normalization, since it has been emphasized in the literature that using multiple reference genes increases accuracy. Two different software tools, geNorm and Normfinder, were used to identify the most stable reference genes in grapevine under the aforementioned conditions. The importance of the choice of adequate reference genes is highlighted by studying chitinase expression.
Asunto(s)
Perfilación de la Expresión Génica/métodos , Genes de Plantas , Oomicetos/patogenicidad , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Vitis/genética , Vitis/microbiología , Quitinasas/genética , Genes Esenciales , Programas InformáticosRESUMEN
BACKGROUND: The incidence of ovarian metastases at the time of peritoneal carcinomatosis, and the influence of such metastases on survival after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), are unknown. METHODS: This retrospective analysis included 194 women subjected to CRS and HIPEC since 2001. The incidence of ovarian metastases, disease-free survival and disease-specific survival were analysed. RESULTS: The histological diagnosis was colorectal cancer carcinomatosis in 108 patients, peritoneal mucinous carcinomatosis (PMCA) in 23 and disseminated peritoneal adenomucinosis (DPAM) in 63. Ninety-nine patients underwent oophorectomy during the HIPEC procedure. Ovarian metastases were confirmed in at least 52 per cent of the patients. There was a significant difference in disease-free survival between women with or without ovarian metastases in both PMCA and DPAM groups (P = 0·044 and P = 0·010 respectively). No significant differences in survival were found in the group with colorectal cancer carcinomatosis. CONCLUSION: When peritoneal carcinomatosis of colorectal or appendiceal origin is confirmed, at least 52 per cent of ovaries will have synchronous metastases. Disease-free survival after a HIPEC procedure for PMCA or DPAM is significantly lower in women with ovarian metastases. Oophorectomy during CRS for peritoneal carcinomatosis should be strongly considered.
Asunto(s)
Adenocarcinoma Mucinoso/cirugía , Neoplasias del Apéndice , Neoplasias Colorrectales , Neoplasias Ováricas/cirugía , Ovariectomía/métodos , Neoplasias Peritoneales/cirugía , Adenocarcinoma Mucinoso/tratamiento farmacológico , Adenocarcinoma Mucinoso/metabolismo , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Quimioterapia del Cáncer por Perfusión Regional/métodos , Supervivencia sin Enfermedad , Femenino , Humanos , Inyecciones Intraperitoneales , Estimación de Kaplan-Meier , Persona de Mediana Edad , Recurrencia Local de Neoplasia/etiología , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/secundario , Neoplasias Peritoneales/secundario , Estudios Retrospectivos , Resultado del Tratamiento , Adulto JovenRESUMEN
The complement system is an important defense mechanism against pathogens; however, in certain pathologies, the system also attacks human cells, such as red blood cells (RBCs). In paroxysmal nocturnal hemoglobinuria (PNH), RBCs lack certain complement regulators which sensitize them to complement-mediated lysis, while in autoimmune hemolytic anemia (AIHA), antibodies against RBCs may initiate complement-mediated hemolysis. In recent years, complement inhibition has improved treatment prospects for these patients, with eculizumab now the standard of care for PNH patients. Current complement inhibitors are however not sufficient for all patients, and they come with high costs, patient burden, and increased infection risk. This review gives an overview of the underlying pathophysiology of complement-mediated hemolysis in PNH and AIHA, the role of therapeutic complement inhibition nowadays, and the high number of complement inhibitors currently under investigation, as for almost every complement protein, an inhibitor is being developed. The focus lies with novel therapeutics that inhibit complement activity specifically in the pathway that causes pathology or those that reduce costs or patient burden through novel administration routes.
Asunto(s)
Hemoglobinuria Paroxística , Inactivadores del Complemento/metabolismo , Inactivadores del Complemento/farmacología , Inactivadores del Complemento/uso terapéutico , Proteínas del Sistema Complemento/metabolismo , Eritrocitos/metabolismo , Eritrocitos/patología , Hemoglobinuria Paroxística/tratamiento farmacológico , Hemoglobinuria Paroxística/etiología , Hemólisis , HumanosRESUMEN
In the past decade, 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (18F-FDG PET-CT) scans have been increasingly implemented in the diagnostic process of several haemato-oncological conditions. Accurate assessment of bone marrow activity observed on 18F-FDG PET-CT is crucial for a correct diagnostic conclusion, subsequent treatment decision, and follow-up strategies. By systematically considering the arguments of the level of 18F-FDG uptake, distribution pattern, coinciding changes of the bone structure, and the clinical context, interpretation and validity may improve. This review aims to give a comprehensive overview of the different patterns of 18F-FDG uptake on PET/CT in common benign, clonal, and malignant haematological conditions, accompanied by illustrative cases.
Asunto(s)
Médula Ósea , Fluorodesoxiglucosa F18/farmacología , Enfermedades Hematológicas/diagnóstico , Neoplasias Hematológicas/diagnóstico , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Médula Ósea/diagnóstico por imagen , Médula Ósea/patología , Diagnóstico Diferencial , Humanos , Radiofármacos/farmacologíaRESUMEN
The Mediterranean Region has a long lasting legacy of mercury mining activities and a high density of sub-marine volcanoes that has strongly contributed to its mercury budget. In the last forty years, there have been recorded increases in mercury concentrations in biota that have spurred a growing number of research activities to assess the impact of mercury pollution on human health and environment. Field investigations that quantify mercury concentrations in marine biota have led to a large amount of experimental data scattered in many peer-reviewed publications making it difficult for modelling applications and regional environmental assessments. This paper reviews existing peer-reviewed literature and datasets on mercury concentration in marine flora and fauna (Animal, Plants and Chromista Kingdoms) in the Mediterranean basin. A total of 24,465 records have been retrieved from 539 sources and included in Mercury in Mediterranean Biota (M2B). Well-defined specimens account for 24,407 observations, while a few records include generic plankton and unidentified fish species. Among all considered species, we selected Diplodus sargus, Sardina pilchardus, Thunnus thynnus and Xiphias gladius to show trends of mercury concentration against WHO and EU limits. Few notes on how M2B is intended to support the implementation of the Minamata Convention on Mercury by a user-driven Knowledge Hub are finally reported.
Asunto(s)
Monitoreo del Ambiente , Peces , Mercurio/análisis , Contaminantes Químicos del Agua/análisis , Animales , Biota , Mar MediterráneoAsunto(s)
Volumen Sanguíneo , Citaféresis , Hemocromatosis , Modelos Biológicos , Flebotomía , Policitemia Vera , Policitemia , Femenino , Hematócrito , Hemocromatosis/fisiopatología , Hemocromatosis/terapia , Humanos , Masculino , Policitemia/fisiopatología , Policitemia/terapia , Policitemia Vera/fisiopatología , Policitemia Vera/terapiaRESUMEN
Mercury (Hg) exposure was evaluated in bald eagles (Haliaeetus leucocephalus) in the lower Penobscot River watershed (PRW) in Maine to assess whether Hg discharges from a chlor-alkali plant (HoltraChem) influenced Hg concentrations in nestling tissues. Mean Hg concentrations in nestling blood and breast feathers sampled in marine and estuarine areas potentially contaminated with Hg from HoltraChem (the potential Hg impact zone) were significantly greater than those from reference sites spanning the Maine coast. To place Hg exposure in the potential Hg impact zone into a broader context, Hg exposure in bald eagle nestlings from four habitat types in the PRW was assessed. Mercury concentrations varied significantly across habitat types within the PRW, generally following the pattern: marine=estuarineAsunto(s)
Águilas/metabolismo
, Monitoreo del Ambiente
, Contaminantes Ambientales/metabolismo
, Mercurio/metabolismo
, Animales
, Plumas
, Maine
RESUMEN
BACKGROUND: Although mental stress is commonly considered to be an important trigger factor for migraine, experimental evidence for this belief is yet lacking. OBJECTIVE: To study the temporal relationship between changes in stress-related parameters (both subjective and objective) and the onset of a migraine attack. METHODS: This was a prospective, ambulatory study in 17 migraine patients. We assessed changes in perceived stress and objective biological measures for stress (saliva cortisol, heart rate average [HRA], and heart rate variability [low-frequency power and high-frequency power]) over 4 days prior to the onset of spontaneous migraine attacks. Analyses were repeated for subgroups of patients according to whether or not they felt their migraine to be triggered by stress. RESULTS: There were no significant temporal changes over time for the whole group in perceived stress (p=0.50), morning cortisol (p=0.73), evening cortisol (p=0.55), HRA (p=0.83), low-frequency power (p=0.99) and high-frequency power (p=0.97) prior to or during an attack. Post hoc analysis of the subgroup of nine stress-sensitive patients who felt that >2/3 of their migraine attacks were triggered by psychosocial stress, revealed an increase for perceived stress (p=0.04) but no changes in objective stress response measures. At baseline, this group also showed higher scores on the Penn State Worry Questionnaire (p=0.003) and the Cohen Perceived Stress Scale (p=0.001) compared to non-stress-sensitive patients. CONCLUSIONS: Although stress-sensitive patients, in contrast to non-stress-sensitive patients, may perceive more stress in the days before an impending migraine attack, we failed to detect any objective evidence for a biological stress response before or during migraine attacks.
Asunto(s)
Hidrocortisona/metabolismo , Trastornos Migrañosos/etiología , Autoevaluación (Psicología) , Estrés Psicológico/complicaciones , Adulto , Ritmo Circadiano/fisiología , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Trastornos Migrañosos/metabolismo , Estudios Prospectivos , Saliva/metabolismo , Estrés Psicológico/metabolismoRESUMEN
A 66-year old woman was admitted with an acute symptomatic abdominal aortic aneurysm. After preoperative assessment, she was directly operated on via transperitoneal approach. Intraoperatively, a left-sided inferior vena cava was diagnosed. The preoperative study of the abdominal computed tomography had not revealed this venous malformation. Retroperitoneal venous anomalies are a major source of unexpected haemorrhage during aortic reconstruction. Thus, for optimal preoperative preparation, a systematic close examination of the preoperative contrast enhanced CT scan of the abdomen is advised.
Asunto(s)
Aneurisma de la Aorta Abdominal/complicaciones , Vena Cava Inferior/anomalías , Anciano , Aneurisma de la Aorta Abdominal/diagnóstico por imagen , Femenino , Humanos , Tomografía Computarizada por Rayos X , Vena Cava Inferior/diagnóstico por imagenRESUMEN
BACKGROUND: The success of radiofrequency (RF) ablation is limited by the inability to assess thermal tissue damage achieved during or immediately after the procedure. The goal of this proof-of-principle study was to investigate whether diffuse reflectance (DR) spectroscopy during and after RF ablation of liver tumours could aid in detecting complete tissue ablation. MATERIAL AND METHODS: DR spectra were acquired in vivo in eight patients undergoing RF ablation for unresectable colorectal liver metastases, using a disposable spectroscopy needle. Intraoperative ultrasound imaging was used for accurate positioning of the RF electrode and the spectroscopy needle. Spectral changes were quantified and correlated to tissue histopathology and follow-up CT imaging. RESULTS: For the lesions in which ablation was monitored by DR spectroscopy (N = 8), median tumour size was 1.6 cm (range 0.8-3.3 cm). We found an excellent correlation (97-99%) between thermal damage suggested by spectral changes and histology. DR spectroscopy allowed discrimination between non-ablated and ablated tissue, regardless whether the needle was placed in tumour tissue or in surrounding liver tissue. Additional measurements performed continuously during ablation confirmed that the magnitude of spectral change correlates with the histochemical degree of thermal damage. CONCLUSIONS: Diffuse reflectance spectroscopy allows accurate quantification of thermal tissue damage during and after RF ablation. Real-time feedback by DR spectroscopy could improve the accuracy and quality of the RF procedures by lowering incomplete ablation rates.
Asunto(s)
Ablación por Catéter , Neoplasias Colorrectales/patología , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/cirugía , Análisis Espectral/métodos , Anciano , Área Bajo la Curva , Femenino , Humanos , Neoplasias Hepáticas/secundario , Masculino , Persona de Mediana Edad , Curva ROC , Tomografía Computarizada por Rayos X , Carga TumoralRESUMEN
Previous studies indicated a reproducible pattern of altered glycosphingolipid biosynthesis accompanying late stages of liver tumorigenesis in the rat induced by the carcinogen 2-acetylaminofluorene. The sequence began with a dramatic elevation in CMP-sialic acid:lactosylceramide sialyltransferase and was followed by sequential elevations and eventual depressions in other enzymes catalyzing sugar transfers to glycolipid acceptors. The present study focused on the early events of glycolipid biosynthesis during the first 11 weeks of 2-acetylaminofluorene administration according to the same feeding schedule as used previously. Transient elevations in CMP-sialic acid synthetase and elevations in neutral glycosphingolipid precursors to gangliosides were found to precede the major elevations in CMP-sialic acid:lactosylceramide sialyltransferase (GM3 synthetase) noted earlier. Two cycles of response were observed prior to the initiation of the sustained enhancement of biosynthesis of precursor ganglioside, GM3, and/or a significant increase in total or lipid-soluble sialic acid. In vitro rates of sialyl transfer from CMP-sialic acid to endogenous protein acceptors were not altered. The results suggest that the previous observations of altered ganglioside biosynthesis following 2-acetylaminofluorene administration are not an isolated occurrence but may represent late events in a sequence or 'cascade' of biochemical change involving, as well, biosynthesis of ganglioside precursors, CMP-sialic acid and neutral glycosphingolipids.
Asunto(s)
2-Acetilaminofluoreno , Transformación Celular Neoplásica/metabolismo , Glucolípidos/biosíntesis , Neoplasias Hepáticas/metabolismo , Animales , Ácido N-Acetilneuramínico Citidina Monofosfato/metabolismo , Glicoesfingolípidos/metabolismo , Hígado/metabolismo , Neoplasias Hepáticas/inducido químicamente , Masculino , Ácido N-Acetilneuramínico , N-Acilneuraminato Citidililtransferasa/metabolismo , Ratas , Ratas Endogámicas F344 , Ácidos Siálicos/metabolismo , Sialiltransferasas/metabolismoRESUMEN
Fibronectin is a high molecular weight adhesive glycoprotein present both on the cell surface (cellular fibronectin) and circulating free in the plasma (plasma fibronectin). To investigate the cellular origins of plasma fibronectin, monoclonal antibodies prepared against purified plasma fibronectin of the rat were used in both in vivo and in vitro pulse-chase experiments comparing livers of animals of different ages. For in vitro analyses, slices were pulsed with 3H-leucine and purified fractions of endoplasmic reticulum, Golgi apparatus and plasma membrane were prepared at various times post-chase and characterized morphologically. The total protein was solubilized with NP-40, and incorporation into fibronectin was determined from PAGE analysis of immunoprecipitates. Incorporation was greatest in 5-day-old animals, representing greater than 0.3% of the total radioactivity and was least in adults animals. Label appeared in fibronectin associated with the plasma membrane within 60 min. At earlier times, labeled fibronectin appeared first in the endoplasmic reticulum (30 min) and then in the Golgi apparatus (45 min). The findings demonstrate synthesis of fibronectin by rat liver and evidence for participation of liver endomembranes in its secretion.
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Fibronectinas/metabolismo , Hígado/metabolismo , Animales , Anticuerpos Monoclonales , Fibronectinas/biosíntesis , Fibronectinas/sangre , Técnicas In Vitro , Cinética , Hígado/ultraestructura , Microscopía Electrónica , Ratas , Fracciones Subcelulares/metabolismoRESUMEN
The YPT1/RAB1 protein, a key regulator of the intracellular vesicle transport in eukaryotes, is highly conserved in function and amino acid sequence. Here we report that the most highly conserved nucleotide sequence of the Rab1a gene of amniote vertebrates corresponds to the 3'-untranslated region (3'-UTR) of the mRNA. Sequences of 27 species ranging from mammals to sauropsida are >91% identical in this region. Secondary structure prediction procedures applied to the 3'-UTR sequences between positions 750 and 984 and 1428 (mouse cDNA: Y00094), respectively, of the RAB1a mRNAs revealed families of alternative structures around nucleotide position 800 as recurrent features. The two hairpin loops are also predicted for marsupials, despite of their exceptional extension of the A-rich sequence in between. Yet, sequence conservation is much higher than required to conserve secondary structure. Implications for posttranscriptional regulation and protein binding are discussed.
Asunto(s)
Regiones no Traducidas 3'/genética , Secuencia Conservada/genética , Marsupiales/genética , Conformación de Ácido Nucleico , Secuencias Reguladoras de Ácidos Nucleicos/genética , Proteínas de Unión al GTP rab1/genética , Regiones no Traducidas 3'/química , Regiones no Traducidas 3'/fisiología , Animales , Secuencia de Bases , Sitios de Unión , Transporte Biológico , Regulación de la Expresión Génica/genética , Humanos , Modelos Biológicos , Datos de Secuencia Molecular , Unión Proteica , Estabilidad del ARN , Proteínas de Unión al ARN/metabolismo , Secuencias Reguladoras de Ácidos Nucleicos/fisiología , Alineación de SecuenciaRESUMEN
Two poly(ethylene glycol) (PEG)-peptides were synthesized and tested for their ability to bind to plasmid DNA and form soluble DNA condensates with reduced spontaneous gene expression. PEG-vinyl sulfone or PEG-orthopyridyl disulfide were reacted with the sulfhydryl of Cys-Trp-Lys(18) (CWK(18)) resulting in the formation of nonreducible (PEG-VS-CWK(18)) and reducible (PEG-SS-CWK(18)) PEG-peptides. Both PEG-peptides were prepared on a micromole scale, purified by RP-HPLC in >80% yield, and characterized by (1)H NMR and MALDI-TOF. PEG-peptides bound to plasmid DNA with an apparent affinity that was equivalent to alkylated (Alk)CWK(18), resulting in DNA condensates with a mean diameter of 80-90 nm and zeta (zeta) potential of +10 mV. The particle size of PEG-peptide DNA condensates was constant throughout the DNA concentration range of 0. 05-2 mg/mL, indicating these to be approximately 20-fold more soluble than AlkCWK(18) DNA condensates. The spontaneous gene transfer to HepG2 cells mediated by PEG-VS-CWK(18) DNA condensates was over two orders of magnitude lower than PEG-SS-CWK(18) DNA condensates and three orders of magnitude lower than AlkCWK(18) DNA condensates. PEG-VS-CWK(18) efficiently blocked in vitro gene transfer by reducing cell uptake. The results indicate that a high loading density of PEG on DNA is necessary to achieve highly soluble DNA condensates that reduce spontaneous in vitro gene transfer by blocking nonspecific uptake by HepG2 cells. These two properties are important for developing targeted gene delivery systems to be used in vivo.
Asunto(s)
ADN/química , Péptidos/química , Polietilenglicoles/química , Línea Celular , Cromatografía Líquida de Alta Presión , ADN/síntesis química , Técnicas de Transferencia de Gen , Humanos , Radioisótopos de Yodo , Hígado/citología , Hígado/metabolismo , Tamaño de la Partícula , Péptidos/síntesis química , Plásmidos , Polietilenglicoles/síntesis química , SolubilidadRESUMEN
In woody plants, chilling stress occurs during the early spring growth and can have important economic consequences. The aim of this study was to compare the reliability of two different experimental systems, 3-month-old softwood cuttings and in vitro-grown shoots, to study chilling effects in a poplar clone (Populus tremula×P. tremuloides cv. Muhs1). Different parameters were recorded: lignin content, sucrose concentration and protein and fresh weight variation, during a 2-week treatment at 10ââ°C. Two families of polypeptides of high molecular weight (110 and 116 kDa) were shown to accumulate in response to chilling in both cuttings and microshoots. For some of the parameters studied, i.e. appearance of some groups of polypeptides and reduction of fresh weight gain, both in vitro and ex vitro systems were suitable and produced similar results. In contrast, for some other observations, i.e. on sucrose concentration and lignin content, the systems led to different conclusions. While sucrose and lignin contents were shown to increase in cuttings submitted to chilling, no variation in lignin and only a small temporary peak of sucrose could be observed in microshoots kept under chilling. These parameters seem not to be suitable for studying the response of poplar in the in vitro system in such a short-term study.