CONTRASTING GERMINATION AND SEEDLING GROWTH OF BETULA ALLEGHANIENSIS AND RHUS TYPHINA SUBJECTED TO VARIOUS AMOUNTS AND TYPES OF PLANT LITTER

Several characteristics of the environment, such as plant litter, may interact with species characteristics, such as seed size, to determine patterns of plant establishment and thereby influence abundance and spatial location of plants long after the factor has itself disappeared. To determine if litter might differentially affect seedling establishment of Betula alleghaniensis Britton and Rhus typhina L., two woody species with different sized seeds, we conducted two greenhouse experiments. We documented emergence, morphology, and growth patterns of seedlings covered by three amounts each of Fagus grandifolia Ehrh. leaves or Tsuga canadensis L. needles. All amounts of litter significantly reduced and delayed final Betula alleghaniensis seedling emergence, and the resultant seedlings had reduced root: shoot ratios, longer hypocotyls, and were less robust. Litter did not affect Rhus typhina emergence but did alter biomass allocation: stem, leaf, and root biomass of Rhus seedlings was reduced by greater amounts of litter, and by leaf litter relative to needle litter. We attribute the different responses of Betula and Rhus to differences in seed size (Betula mean seed size = 1.0 mg; Rhus mean seed size = 8.5 mg) and germination cues (Betula requires light, Rhus requires chemical or heat scarification), and suggest that differential response to litter may contribute to coexistence among these sympatric species.     

Haptoglobin and CCR2 receptor expression in ovarian cancer cells that were exposed to ascitic fluid: Exploring a new role of haptoglobin in the tumoral microenvironment

Haptoglobin (Hp) is an acute-phase protein that is produced by the liver to capture the iron that is present in the blood circulation, thus avoiding its accumulation in the blood. Moreover, Hp has been detected in a wide variety of tissues, in which it performs various functions. In addition, this protein is considered a potential biomarker in many diseases, such as cancer, including ovarian carcinoma; however, its participation in the cancerous processes has not yet been determined. The objective of this work was to demonstrate the expression of Hp and its receptor CCR2 in the ovarian cancer cells and its possible involvement in the process of cell migration through changes in the rearrangement of the actin cytoskeleton using western blot and wound-healing assays and confirming by confocal microscopy. Ovarian cancer cells express both Hp and its receptor CCR2 but only after exposure to ascitic fluid, inducing moderated cell migration. However, when the cells are exposed to exogenous Hp, the expression of CCR2 is induced together with drastic changes in the actin cytoskeleton rearrangement. At the same time, Hp induced cell migration in a much more efficient manner than did ascitic fluid. These effects were blocked when the CCR2 synthetic antagonist RS102895 was used to pretreat the cells. These results suggest that Hp-induced changes in the cell morphology, actin cytoskeleton structure, and migration ability of tumor cells, is possibly “preparing” these cells for the potential induction of the metastatic phenotype.     

Role of HLA DRB1*15 and HLA DRB1*16alleles in the genetic susceptibility to develop systemic lupus erythematosus (SLE) after Chikungunya and Zika viruses infection in México

Systemic lupus erythematosus (SLE) is a clinically and genetically heterogeneous disease particularly prevalent in Mexico. Althoughits etiology is unknown, genetic factors strongly influence its presenceas well as triggering factors, such as viral infections, including Cytomegalovirus and Epstein-Barr virus. Here,the study presents the appearance of de novoSLE (patients who did not present SLE before de virus infection, corroborated by serological analysis and negative for antinuclear antibodies) cases in Mexicans who live near the southern border of Mexico, who presented clinical symptoms of arthritic, hematological, mucocutaneous and renal SLE, after Zika and/ or Chikungunya virus infection. Low resolution class Ⅱ HLA typing was performed, which found a significantly increased frequency of HLA DRB1*02 (15 and 16)when compared to a group of 99 healthy individuals (P =0.001, OR=4.5, IC95% 1.8~11.0). All the patients were diagnosed with SLE 1 to 3 years after being confirmed with the Zika, and/or Chikungunya infection. At the point of acute viral infection, none of the patients presented clinical signs or symptoms of autoimmunity or were negative for antinuclear antibodies. In genetically susceptible individuals, Zika and Chikungunya viral infection can trigger SLE.     

Transition from exo- to endo- Cu absorption in CuSi(n) clusters: A Genetic Algorithms Density Functional Theory (DFT) Study

The characterization and prediction of the structures of metal silicon clusters is important for nanotechnology research because these clusters can be used as building blocks for nano devices, integrated circuits and solar cells. Several authors have postulated that there is a transition between exo to endo absorption of Cu in Si(n) clusters and showed that for n larger than 9 it is possible to find endohedral clusters. Unfortunately, no global searchers have confirmed this observation, which is based on local optimizations of plausible structures. Here we use parallel Genetic Algorithms (GA), as implemented in our MGAC software, directly coupled with DFT energy calculations to show that the global search of CuSi(n) cluster structures does not find endohedral clusters for n < 8 but finds them for n ≥ 10.     

An optimized microarray platform for assaying genomic variation in <Emphasis Type="Italic">Plasmodium falciparum</Emphasis> field populations

We present an optimized probe design for copy number variation (CNV) and SNP genotyping in the Plasmodium falciparum genome. We demonstrate that variable length and isothermal probes are superior to static length probes. We show that sample preparation and hybridization conditions mitigate the effects of host DNA contamination in field samples. The microarray and workflow presented can be used to identify CNVs and SNPs with 95% accuracy in a single hybridization, in field samples containing up to 92% human DNA contamination.