Photocatalytic Activity of Composites for Ethylene Degradation Under UV-A and Visible Light

Ethylene is a natural hormone responsible for many processes, including ripening. One way to extend the shelf life of several fruits and vegetables is to remove ethylene from the atmosphere of storage and transport, for which photocatalysis processes can be an efficient technology. In this study, we investigated the ethylene photodegradation of four different composites (Cu/C3N4, Cu/TiO2, Ni/C3N4, Ni/TiO2) under UV-A and visible illumination. The photocatalytic composites were characterized, and the photocatalytic assay was performed in a continuous system for 1 h (ethylene concentration at 1.0 % in synthetic air, 50 mL.min-1, and 400 mg of photocatalyst). The results indicated that the Cu/C3N4 sample did not produce carbon dioxide under visible light or UV-A illumination, so ethylene was not degraded. The Ni/TiO2 sample had the best performance for ethylene degradation under visible light and UV-A illumination, showing higher CO2 production with UV-A. After illumination for 1 h, the light was turned off, and 5 min later, the CO2 concentration at the outlet was equal to the initial. Thus, the composites Ni/C3N4, Cu/TiO2, and Ni/TiO2 proved to be efficient in ethylene degradation. Therefore, they can increase the shelf life of fruits and vegetables, using photocatalysis to remove ethylene from the atmosphere while storing and transporting these foods

Mantos eólicos en la costa septentrional de Menorca: naturaleza y distribución

[spa]Han sido analizados un total de 11 mantos eólicos de Menorca (Islas Baleares). Su principal característica es que todos ellos están ubicados en la costa norte de la isla. Pueden agruparse en tres tipos principales: los relacionados con los acantilados verticales, los relacionados con lechos de torrentes, y un tercer tipo intermedio con características de ambos grupos anteriores, que corresponde a torrentes colgados. La génesis y la evolución pueden estar relacionadas con la erosión mecánica y/o movimientos verticales asociados con el nivel del mar eustático en el Holoceno.[eng]Eleven aeolian sand sheets have been studied on the island of Menorca (Balearic Islands). Their principal feature is that they are all located on the north coast of the island. They can be grouped into three main types: those related to vertical cliffs, those related to stream channels, and a third intermediate type with characteristics of both previous groups, which corresponds to hanging channels in the mouths. The genesis and evolution can be related to mechanical erosion and/or vertical movements associated with eustatic sea levels in the Holocene

Epigenetic Mechanisms Regulate MHC and Antigen Processing Molecules in Human Embryonic and Induced Pluripotent Stem Cells

Background Human embryonic stem cells (hESCs) are an attractive resource for new therapeutic approaches that involve tissue regeneration. hESCs have exhibited low immunogenicity due to low levels of Mayor Histocompatibility Complex (MHC) class-I and absence of MHC class-II expression. Nevertheless, the mechanisms regulating MHC expression in hESCs had not been explored. Methodology/Principal Findings We analyzed the expression levels of classical and non-classical MHC class-I, MHC class-II molecules, antigen-processing machinery (APM) components and NKG2D ligands (NKG2D-L) in hESCs, induced pluripotent stem cells (iPSCs) and NTera2 (NT2) teratocarcinoma cell line. Epigenetic mechanisms involved in the regulation of these genes were investigated by bisulfite sequencing and chromatin immunoprecipitation (ChIP) assays. We showed that low levels of MHC class-I molecules were associated with absent or reduced expression of the transporter associated with antigen processing 1 (TAP-1) and tapasin (TPN) components in hESCs and iPSCs, which are involved in the transport and load of peptides. Furthermore, lack of β2-microglobulin (β2m) light chain in these cells limited the expression of MHC class I trimeric molecule on the cell surface. NKG2D ligands (MICA, MICB) were observed in all pluripotent stem cells lines. Epigenetic analysis showed that H3K9me3 repressed the TPN gene in undifferentiated cells whilst HLA-B and β2m acquired the H3K4me3 modification during the differentiation to embryoid bodies (EBs). Absence of HLA-DR and HLA-G expression was regulated by DNA methylation. Conclusions/Significance Our data provide fundamental evidence for the epigenetic control of MHC in hESCs and iPSCs. Reduced MHC class I and class II expression in hESCs and iPSCs can limit their recognition by the immune response against these cells. The knowledge of these mechanisms will further allow the development of strategies to induce tolerance and improve stem cell allograft acceptance

Genome-wide tracking of unmethylated DNA Alu repeats in normal and cancer cells

Methylation of the cytosine is the most frequent epigenetic modification of DNA in mammalian cells. In humans, most of the methylated cytosines are found in CpG-rich sequences within tandem and interspersed repeats that make up to 45% of the human genome, being Alu repeats the most common family. Demethylation of Alu elements occurs in aging and cancer processes and has been associated with gene reactivation and genomic instability. By targeting the unmethylated SmaI site within the Alu sequence as a surrogate marker, we have quantified and identified unmethylated Alu elements on the genomic scale. Normal colon epithelial cells contain in average 25 486 ± 10 157 unmethylated Alu's per haploid genome, while in tumor cells this figure is 41 995 ± 17 187 (P = 0.004). There is an inverse relationship in Alu families with respect to their age and methylation status: the youngest elements exhibit the highest prevalence of the SmaI site (AluY: 42%; AluS: 18%, AluJ: 5%) but the lower rates of unmethylation (AluY: 1.65%; AluS: 3.1%, AluJ: 12%). Data are consistent with a stronger silencing pressure on the youngest repetitive elements, which are closer to genes. Further insights into the functional implications of atypical unmethylation states in Alu elements will surely contribute to decipher genomic organization and gene regulation in complex organisms

A human genome editing-based MLL::AF4 B-cell ALL model recapitulates key cellular and molecular leukemogenic features

The cellular ontogeny and location of the MLL-breakpoint influence the capacity of MLL-edited CD34+ HSPCs to initiate pro-B-ALL, and recapitulate the molecular features of MLL-AF4+ infant B-ALL patients. We provide key insights into the cellular-molecular leukemogenic determinants of MLL-AF4+ infant B-ALL

Chronic lymphocytic leukemia cells in lymph nodes show frequent NOTCH1 activation

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the Western world. Pathogenic mechanisms involve multiple external events (such as microenvironmental and antigenic stimuli) and internal events (genetic and epigenetic alterations) that are associated with the transformation, progression and evolution of CLL. CLL is characterized by an accumulation of mature B cells in peripheral blood, bone marrow and lymphoid tissues. Extracellular stimuli play an important role in the development and maintenance of neoplastic cells. B-CLL cells proliferate and activate pathogenic signaling pathways in anatomical structures known as proliferation centers, which are usually more conspicuous in involved lymph nodes.1 Its clinical course is quite heterogeneous, whereby some patients progress rapidly and have short survival, whereas others have a more stable clinical course that may not need treatment for years.This work was supported by grants from the Ministerio de Economía y Competitividad (MINECO) (SAF2013-47416-R) Instituto de Salud Carlos III (ISCIII)- FEDER – MINECO- AES (CP11/00018, PI10/00621, RD012/0036/0060), and Asociación Española contra el Cancer (AECC). MS-B is supported by a Miguel Servet contract from ISCIII-FEDER (CP11/00018). Salary support to SG is provided by CP11/00018, from ISCIII-FEDER. JG-R is supported by a predoctoral grant from the Fundación Investigación Puerta de Hierro.S

The context and potential of epigenetics in oncology

Cancer has long been known to be a disease caused by alterations in the genetic blueprint of cells. In the past decade it has become evident that epigenetic processes have a function, at least equally important, in neoplasia. Epigenetics describes the mechanisms that result in heritable alterations in gene expression profiles without an accompanying change in DNA sequence. Genetics and epigenetics intricately interact in the pathogenesis of cancer (Esteller, 2007). In this review, we paint a broad picture of current understanding of epigenetic changes in cancer cells and reflect on the immense clinical potential of emerging knowledge of epigenetics in the diagnosis, prognostic assessment, treatment, and screening of cancer

Family History and Breast Cancer Hormone Receptor Status in a Spanish Cohort

Breast cancer is a heterogenous disease that impacts racial/ethnic groups differently. Differences in genetic composition, lifestyles, reproductive factors, or environmental exposures may contribute to the differential presentation of breast cancer among Hispanic women.A population-based study was conducted in the city of Santiago de Compostela, Spain. A total of 645 women diagnosed with operable invasive breast cancer between 1992 and 2005 participated in the study. Data on demographics, breast cancer risk factors, and clinico-pathological characteristics of the tumors were collected. Hormone receptor negative tumors were compared with hormone receptor postive tumors on their clinico-pathological characteristics as well as risk factor profiles.Among the 645 breast cancer patients, 78% were estrogen receptor-positive (ER+) or progesterone receptor-positive (PR+), and 22% were ER−&PR−. Women with a family history of breast cancer were more likely to have ER−&PR− tumors than women without a family history (Odds ratio, 1.43; 95% confidence interval, 0.91–2.26). This association was limited to cancers diagnosed before age 50 (Odds ratio, 2.79; 95% confidence interval, 1.34–5.81).An increased proportion of ER−&PR− breast cancer was observed among younger Spanish women with a family history of the disease

HIV-1 infected monozygotic twins: a tale of two outcomes

<p>Abstract</p> <p>Background</p> <p>Replicate experiments are often difficult to find in evolutionary biology, as this field is inherently an historical science. However, viruses, bacteria and phages provide opportunities to study evolution in both natural and experimental contexts, due to their accelerated rates of evolution and short generation times. Here we investigate HIV-1 evolution by using a natural model represented by monozygotic twins infected synchronically at birth with an HIV-1 population from a shared blood transfusion source. We explore the evolutionary processes and population dynamics that shape viral diversity of HIV in these monozygotic twins.</p> <p>Results</p> <p>Despite the identical host genetic backdrop of monozygotic twins and the identical source and timing of the HIV-1 inoculation, the resulting HIV populations differed in genetic diversity, growth rate, recombination rate, and selection pressure between the two infected twins.</p> <p>Conclusions</p> <p>Our study shows that the outcome of evolution is strikingly different between these two "replicates" of viral evolution. Given the identical starting points at infection, our results support the impact of random epigenetic selection in early infection dynamics. Our data also emphasize the need for a better understanding of the impact of host-virus interactions in viral evolution.</p