423 research outputs found
Comparison of drought stress response and gene expression between a GM maize variety and a near-isogenic non-GM variety
Maize MON810, grown and commercialised worldwide, is the only cultivated GM event in the EU. Maize MON810, variety DKC6575, and the corresponding near-isogenic line Tietar were studied in different growth conditions, to compare their behaviour in response to drought. Main photosynthetic parameters were significantly affected by water stress in both GM and non –GM varieties to a similar extents. Though DKC6575 (GM) had a greater sensitivity in the early phase of stress response as compared with Tietar (non GM), after six days of stress they behaved similarly, and both varieties recovered from stress damage.
Profiling gene expression in water deficit regimes and in a generalised water stress condition showed an up-regulation of many stress- responsive genes, but a greater number of differentially expressed genes was observed in Tietar, with genes belonging to transcription factor families and genes encoding HSPs, LEAs and detoxification enzymes. Since induction of these genes have been indicated from the literature as typical of stress responses, their activation in Tietar rather than in DKC6575 may be reminiscent of a more efficient response to drought. DKC6575 was also analysed for the expression of the transgene CryIAb (encoding the delta-endotoxin insecticidal protein) in water deficit conditions. In all the experiments, the CryIAb transcript was not influenced by water stress, but was expressed at a constant level.. This suggests that though possessing a different pattern of sensitivity to stress, the GM variety maintains the same expression level for the transgene
An integrative dynamic model of Colombian population distribution, based on the maximum entropy principle and matter, energy, and information flow
Human society has increased its capacity to exploit natural resources thanks to new technologies, which are one of the results of information exchange in the knowledge society. Many approaches to understanding the interactions between human society and natural systems have been developed in the last decades, and some have included considerations about information. However, none of them has considered information as an active variable or flowing entity in the human–natural/social-ecological system, or, moreover, even as a driving force of their interactions. This paper explores these interactions in socio-ecological systems by briefly introducing a conceptual frame focused on the exchange of information, matter, and energy. The human population is presented as a convergence variable of these three physical entities, and a population distribution model for Colombia is developed based on the maximum entropy principle to integrate the balances of related variables as macro-state restrictions. The selected variables were electrical consumption, water demand, and higher education rates (energy, matter, and information). The final model includes statistical moments for previous population distributions. It is shown how population distribution can be predicted yearly by combining these variables, allowing future dynamics exploration. The implications of this model can contribute to bridging information sciences and sustainability studies
AGILE Roadmap: diagnóstico y evaluación de prácticas ágiles para ser implementadas en equipos de trabajo
[EN] The elaboration of a list of practices to suit the characteristics of a team is not an easy task due to the large variety of existing agile methods and practices and the absence of a tool that can facilitate the elaboration mainly at the stage of selection of best practices to implement in the team. This paper develops a web tool that meets the main criteria for the preparation of a list of practices adapted to the team or more specifically to a product or service.[ES] La elaboración de una lista de prácticas que se ajuste a las características de un equipo de trabajo no es una tarea fácil debido a la gran variedad de métodos y prácticas ágiles existentes y la falta de una herramienta que pueda facilitar su elaboración principalmente en la etapa de selección de las prácticas más adecuadas para implementar en el equipo de trabajo. En este trabajo se desarrolla una herramienta web que cumple con los criterios principales para la elaboración de un listado de prácticas adaptado al equipo de trabajo o más específicamente a un producto/servicio.Nelson Amancio, FI. (2013). AGILE Roadmap: diagnóstico y evaluación de prácticas ágiles para ser implementadas en equipos de trabajo. http://hdl.handle.net/10251/44469Archivo delegad
Liver Regeneration after Partial Hepatectomy Is Not Impaired in Mice with Double Deficiency of Myd88 and IFNAR Genes
Liver regeneration is known to occur in mice lacking one or more Toll-like receptors (TLRs) or the adaptor protein MyD88. Though MyD88 is required for signaling by many TLRs, others signal via MyD88-independent pathways, leading to the induction of type I interferons (IFNs). Here, we assessed liver regeneration after partial hepatectomy (PH) in mice lacking both MyD88 and the type I IFN receptor (Myd88-IFNAR double-KO). Approximately 28% of Myd88-IFNAR double-KO mice had gross liver lesions prior to surgery. In mice without lesions, Myd88-IFNAR deficiency abrogated the increase in circulating IL-6 after PH but did not impair hepatocyte BrdU incorporation, mitotic figure counts, or recovery of liver-to-body weight ratios. These results indicate that type I IFNs are not responsible for the preservation of liver regeneration in Myd88-deficient mice, and they also cast doubt on the idea of microbial products being essential triggers of liver regeneration in mice undergoing PH
Significância prognóstica das micrometástases ocultas em linfonodos no câncer gástrico: estudo histoquímico e imunoistoquímico baseado nas classificações UICC TNM de 1997 e JCGCA de 1998
BACKGROUND: Micrometastasis is a single or a cluster of malignant cells inside the lymph node that are not detected by routine histopathological sections. Micrometastasis is related to poorer prognosis in many gastric cancer studies the real significance of these cells is still controversial. AIM: To evaluate if lymph node micrometastasis is a significant independent prognostic factor and important risk factor for recurrence in gastric cancer. METHODS: A total of 1290 lymph nodes from 28 patients with gastric cancer, since 1998 until 2003, treated by radical resection (D2 and modified D3 lymphadenectomies) were studied. Three sections per lymph node were stained by Hematoxilin-Eosin, histochemical (AB-PAS) and immunohistochemical (AE1-AE3) techniques. Kaplan-Meier's survival curves and Log-rank/Cox tests were used in order to compares lymph node micrometastasis positivity, depth (pT) and location of tumor in gastric wall, histologic type, lymphatic, vascular and perineural invasion, lymph node status (pN) and stage. RESULTS: There were worse prognosis and recurrence in patients with positive lymph node micrometastasis related to vascular and perineural invasions, advanced lymph node status and advanced stages. CONCLUSION: Lymph node micrometastasis seems to be a significant independent prognostic factor and important risk factor for recurrence in gastric cancer, in a context of radical D2 lymphadenectomyRACIONAL: Micrometástases são um conjunto de células malignas dentro de linfonodo que não são detectadas pelos exames histopatológicos de rotina. Elas são relacionadas a prognóstico mais pobre em muitos estudos sobre câncer gástrico, mas a real significância dessas células permanece controversa. OBJETIVO: Avaliar se micrometástase linfonodal é um fator independente de prognóstico e importante para detectar a recurrência do câncer gástrico. MÉTODOS: Um total de 1290 lifonodos de 28 pacientes com câncer gástrico, de 1998 a 2003, tratados com operações radicais (D2 e D3 modificadas) foram revistos. Três secções por linfonodo foram corados por Hematoxilina-Eosina, histoquímica (AB-PAS) e imunoistoquímica (AE1-AE3). Curvas de sobrevida de Kaplan-Meyer e teste de Log-rank/Cox foram usados para comparar positividade das imcrometástases, profundidade (pT) e localização tumoral na parede gástrica, tipo histológico, invasão linfática, vascular e perineural, estado linfonodal (pN) e estádio onde se encontra a doença. RESULTADOS: Houve pior prognóstico e recurrência nos pacientes com linfonodos com micrometástases relacionadas às invasões vascular e perineural , avançado estado de invasão linfática e estadiamento mais elevado. CONCLUSÃO: Micrometástase parece ser importante e independente fator de risco para recurrência no câncer gástrico no contexto das linfadenectomias radicais D2
A estranha história da cobra narrada na “relaçam prodigioza da navegaçam da nao chamada S. Pedro, e S. Joam da Companhia de Macao” (Fascunh, 1743) – uma obra portuguesa sobre herpetologia
The Portuguese ship “São Pedro e São Paulo” left Macau, China, bound for Portugal, in January 1743. She arrived at the port of Lisbon on 12 September 1743. While unloading the ship, it was discovered that a snake had embarked in her, which was immediately killed and taken to the church of Nossa Senhora da Penha, together with a miniature of the ship, as a token of gratitude to the Virgin, for saving the crew from several dangers and because the snake had not killed any member of it. A wooden model of the snake was made afterwards, to accompany that of the “lagarto da Penha” already existing in that church. Out of curiosity, the Augustinian Father Francisco da Cunha, tried to identify the snake, publishing in that same year of 1743, under the pseudonym of “Ricardo Fineça Fascunh”, the booklet Relaçam da prodigiosa navegaçam da nao chamada S. Pedro, e S. Joam da Companhia de Macao. In this work, in a certain way a treatise of herpetology, Cunha discussed the creation of reptiles by God in the fifth day of the Creation, the etymologies of several snake names, the generation of these reptiles (both sexual and by spontaneous generation), their sympathies and antipathies in relation to other animals and plants, finally listing some 50 species of snakes, in a frustrated attempt to identify the snake which had come from Macau. His commentaries are abridged paraphrases, with some alterations and translation errors, of the works of Jonstonus (1653), precipuously, and Nieremberg (1635), secondarily; he also seems to have consulted the books of Gesner (1587) and Ray (1693), besides some other works. Through his short and insufficient description of the snake transported by the ship “São Pedro e São Paulo”, we can only conjecture that it was a specimen of Pelamis platura (Linnaeus, 1766) (Elapidae, Hydrophiidae)
Defective DNA Strand Break Repair Causes Chromosomal Instability and Accelerates Liver Carcinogenesis in Mice
Chromosomal instability is a characteristic feature of hepatocellular carcinoma (HCC) but its origin and role in liver carcinogenesis are undefined. We tested whether a defect in the nonhomologous end-joining (NHEJ) DNA repair gene Ku70 was associated with chromosomal abnormalities and enhanced liver carcinogenesis. Male Ku70 NHEJ-deficient (Ku70-/-), heterozygote (Ku70 +/-), and wild-type (WT) mice were injected with diethylnitrosamine (DEN), a liver carcinogen, at age 15 days. Animals were killed at 3, 6, and 9 months for assessment of tumorigenesis and hepatocellular proliferation. For karyotype analysis, primary liver tumor cell cultures were prepared from HCCs arising in Ku70 mice of all genotypes. Compared to WT littermates, Ku70-/- mice injected with DEN displayed accelerated HCC development. Ku70-/- HCCs harbored clonal increases in numerical and structural aberrations of chromosomes 4, 5, 7, 8, 10, 14, and 19, many of which recapitulated the spectrum of equivalent chromosomal abnormalities observed in human HCC. Ku70-/- HCCs showed high proliferative activity with increased cyclin D1 and proliferating cell nuclear antigen expression, Aurora A kinase activity, enhanced ataxia telangiectasia mutated kinase and ubiquitination, and loss of p53 via proteasomal degradation, features which closely resemble those of human HCC. Conclusion: These findings demonstrate that defects in the NHEJ DNA repair pathway may participate in the disruption of cell cycle checkpoints leading to chromosomal instability and accelerated development of HCC
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Effect of ethanol on innate antiviral pathways and HCV replication in human liver cells
Alcohol abuse reduces response rates to IFN therapy in patients with chronic hepatitis C. To model the molecular mechanisms behind this phenotype, we characterized the effects of ethanol on Jak-Stat and MAPK pathways in Huh7 human hepatoma cells, in HCV replicon cell lines, and in primary human hepatocytes. High physiological concentrations of acute ethanol activated the Jak-Stat and p38 MAPK pathways and inhibited HCV replication in several independent replicon cell lines. Moreover, acute ethanol induced Stat1 serine phosphorylation, which was partially mediated by the p38 MAPK pathway. In contrast, when combined with exogenously applied IFN-α, ethanol inhibited the antiviral actions of IFN against HCV replication, involving inhibition of IFN-induced Stat1 tyrosine phosphorylation. These effects of alcohol occurred independently of i) alcohol metabolism via ADH and CYP2E1, and ii) cytotoxic or cytostatic effects of ethanol. In this model system, ethanol directly perturbs the Jak-Stat pathway, and HCV replication.
Infection with Hepatitis C virus is a significant cause of morbidity and mortality throughout the world. With a propensity to progress to chronic infection, approximately 70% of patients with chronic viremia develop histological evidence of chronic liver diseases including chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The situation is even more dire for patients who abuse ethanol, where the risk of developing end stage liver disease is significantly higher as compared to HCV patients who do not drink [1, 2].
Recombinant interferon alpha (IFN-α) therapy produces sustained responses (ie clearance of viremia) in 8–12% of patients with chronic hepatitis C [3]. Significant improvements in response rates can be achieved with IFN plus ribavirin combination [4–6] and pegylated IFN plus ribavirin [7, 8] therapies. However, over 50% of chronically infected patients still do not clear viremia. Moreover, HCV-infected patients who abuse alcohol have extremely low response rates to IFN therapy [9], but the mechanisms involved have not been clarified.
MAPKs play essential roles in regulation of differentiation, cell growth, and responses to cytokines, chemokines and stress. The core element in MAPK signaling consists of a module of 3 kinases, named MKKK, MKK, and MAPK, which sequentially phosphorylate each other [10]. Currently, four MAPK modules have been characterized in mammalian cells: Extracellular Regulated Kinases (ERK1 and 2), Stress activated/c-Jun N terminal kinase (SAPK/JNK), p38 MAP kinases, and ERK5 [11]. Interestingly, ethanol modulates MAPKs [12]. However, information on how ethanol affects MAPKs in the context of innate antiviral pathways such as the Jak-Stat pathway in human cells is extremely limited.
When IFN-α binds its receptor, two receptor associated tyrosine kinases, Tyk2 and Jak1 become activated by phosphorylation, and phosphorylate Stat1 and Stat2 on conserved tyrosine residues [13]. Stat1 and Stat2 combine with the IRF-9 protein to form the transcription factor interferon stimulated gene factor 3 (ISGF-3), which binds to the interferon stimulated response element (ISRE), and induces transcription of IFN-α-induced genes (ISG). The ISGs mediate the antiviral effects of IFN. The transcriptional activities of Stats 1, 3, 4, 5a, and 5b are also regulated by serine phosphorylation [14]. Phosphorylation of Stat1 on a conserved serine amino acid at position 727 (S727), results in maximal transcriptional activity of the ISGF-3 transcription factor complex [15]. Although cross-talk between p38 MAPK and the Jak-Stat pathway is essential for IFN-induced ISRE transcription, p38 does not participate in IFN induction of Stat1 serine phosphorylation [14, 16–19]. However, cellular stress responses induced by stimuli such as ultraviolet light do induce p38 MAPK mediated Stat1 S727 phosphorylation [18].
In the current report, we postulated that alcohol and HCV proteins modulate MAPK and Jak-Stat pathways in human liver cells. To begin to address these issues, we characterized the interaction of acute ethanol on Jak-Stat and MAPK pathways in Huh7 cells, HCV replicon cells lines, and primary human hepatocytes
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