Virulence of infecting Helicobacter pyloristrains and intensity of mononuclear cell infiltration are associated with levels of DNA hypermethylation in gastric mucosae

DNA methylation changes are known to occur in gastric cancers and in premalignant lesions of the gastric mucosae. In order to examine variables associated with methylation levels, we quantitatively evaluated DNA methylation in tumors, non-tumor gastric mucosae, and in gastric biopsies at promoters of 5 genes with methylation alterations that discriminate gastric cancers from non-tumor epithelia (EN1, PCDH10, RSPO2, ZIC1, and ZNF610). Among Colombian subjects at high and low risk for gastric cancer, biopsies from subjects from the high-risk region had significantly higher levels of methylation at these 5 genes than samples from subjects in the low risk region (p ≤ 0.003). When results were stratified by Helicobacter pylori infection status, infection with a cagA positive, vacA s1m1 strain was significantly associated with highest methylation levels, compared with other strains (p = 0.024 to 0.001). More severe gastric inflammation and more advanced precancerous lesions were also associated with higher levels of DNA methylation (p ≤ 0.001). In a multivariate model, location of residence of the subject and the presence of cagA and vacA s1m1 in the H. pylori strain were independent variables associated with higher methylation in all 5 genes. High levels of mononuclear cell infiltration were significantly related to methylation in PCDH10, RSPO2, and ZIC1 genes. These results indicate that for these genes, levels of methylation in precancerous lesions are related to H. pylori virulence, geographic region and measures of chronic inflammation. These genes seem predisposed to sustain significant quantitative changes in DNA methylation at early stages of the gastric precancerous process.     

Endosymbiotic bacteria nodulating a new endemic lupine Lupinus mariae-josephi from alkaline soils in Eastern Spain represent a new lineage within the Bradyrhizobium genus

Lupinus mariae-josephi is a recently described endemic Lupinus species from a small area in Eastern Spain where it thrives in soils with active lime and high pH. The L. mariae-josephi root symbionts were shown to be very slow-growing bacteria with different phenotypic and symbiotic characteristics from those of Bradyrhizobium strains nodulating other Lupinus. Their phylogenetic status was examined by multilocus sequence analyses of four housekeeping genes (16S rRNA, glnII, recA, and atpD) and showed the existence of a distinct evolutionary lineage for L. mariae-josephi that also included Bradyrhizobium jicamae. Within this lineage, the tested isolates clustered in three different sub-groups that might correspond to novel sister Bradyrhizobium species. These core gene analyses consistently showed that all the endosymbiotic bacteria isolated from other Lupinus species of the Iberian Peninsula were related to strains of the B. canariense or B. japonicum lineages and were separate from the L. mariae-josephi isolates. Phylogenetic analysis based on nodC symbiotic gene sequences showed that L. mariae-josephi bacteria also constituted a new symbiotic lineage distant from those previously defined in the genus Bradyrhizobium. In contrast, the nodC genes of isolates from other Lupinus spp. from the Iberian Peninsula were again clearly related to the B. canariense and B. japonicum bv. genistearum lineages. Speciation of L. mariae-josephi bradyrhizobia may result from the colonization of a singular habitat by their unique legume host.     

Venezuelan Equine Encephalitis Viruses (VEEV) in Argentina: Serological Evidence of Human Infection

Venezuelan equine encephalitis viruses (VEEV) are responsible for human diseases in the Americas, producing severe or mild illness with symptoms indistinguishable from dengue and other arboviral diseases. For this reason, many cases remain without certain diagnosis. Seroprevalence studies for VEEV subtypes IAB, ID, IF (Mosso das Pedras virus; MDPV), IV (Pixuna virus; PIXV) and VI (Rio Negro virus; RNV) were conducted in persons from Northern provinces of Argentina: Salta, Chaco and Corrientes, using plaque reduction neutralization test (PRNT). RNV was detected in all studied provinces. Chaco presented the highest prevalence of this virus (14.1%). Antibodies against VEEV IAB and -for the first time- against MDPV and PIXV were also detected in Chaco province. In Corrientes, seroprevalence against RNV was 1.3% in the pediatric population, indicating recent infections. In Salta, this was the first investigation of VEEV members, and antibodies against RNV and PIXV were detected. These results provide evidence of circulation of many VEE viruses in Northern Argentina, showing that surveillance of these infectious agents should be intensified.     

A new case of rhinosporidiosis in Chile

BackgroundRhinosporidiosis is a chronic, granulomatous, and non-contagious infection, in which highly vascularized polyps (mainly present in the nasal cavity) appear. These polyps usually bleed easily.AimsTo present the case of a 14 year-old male suffering from an obstruction and injury of the right nostril due to a polypoid shaped-lesion with a raspberry-like appearance.MethodsA wide surgery resection of the base of the lesion was performed, as well as a standard histopathology procedure, including microscopic analysis with haematoxylin-eosin and Grocott staining.Results and conclusionsThe histopathology report indicated that the chronic inflammatory polyp was compatible with rhinosporidiosis.     

Poor geotaxis correlated with haematoporphyrin‐induced peroxidation of brain lipids as a predictor of medfly longevity reduction

Under illumination conditions, porphyrins generate cytotoxic radicals in cells. Our study evaluated the effects of haematoporphyrin IX (HP IX) in a laboratory population of male Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) during exposure to a low fluence rate (39 μE m^?2 s^?1) of light. We found that exposing flies to HP IX for at least 5 days was sufficient to cause irreversible damage that led to anticipated death, as also provoked by chronic exposure to the same concentration. To identify early indicators of the accelerated senescence, we analysed both in vitro and in vivo parameters. The thiobarbituric acid reactive substances content in the heads of treated flies revealed a significant increase in lipid hydroperoxides at day 10, whereas this occurred several days later in controls. In addition, a significant decrease in glycogen content was observed at 15 days of age, 5 days before the reduction observed in the control group. This decrease has been associated with a decline in locomotor activity. Differences in the distribution of flies in the rearing flasks were observed, reflecting an impairment of the motility and climbing capacity of HP IX‐treated flies. This finding was also corroborated by a geotactic response assay (a rapid iterative negative geotaxis or RING assay). The results presented here demonstrate that low‐lethal oxidative stress can anticipate the senescence of flies, which can be predicted using a simple and fast behavioural test, such as the RING assay.     

Morphological and sexual traits in Atlas and Iberian Pied Flycatchers Ficedula hypoleuca speculigera and F. h. iberiae: a comparison

Capsule: There are significant biometric differences between Pied Flycatchers from Iberian and north African populations which are consistent with proposals to classify the two forms into separate species.

Aims: To determine the similarities and differences in the main biometrical and plumage sex traits between populations of the Iberian Pied Flycatcher Ficedula hypoleuca iberiae and the Atlas Flycatcher Ficedula hypoleuca speculigera.

Methods: Biometric and plumage traits of 193 breeding individuals of Iberian Pied Flycatchers and 43 Atlas Flycatchers were measured in 2014 with standardized protocols.

Results: Both sexes of Atlas Flycatchers were larger than Iberian Pied Flycatchers in skeletal (tarsus) and wing size and also differed in bill morphology, which was wider but shallower in speculigera than iberiae, with females (but not males) having shorter bills than iberiae females. Males differed in mantle colour and forehead patch size, with speculigera males being darker and displaying larger forehead patches than iberiae males. As in populations of iberiae, some speculigera females also expressed a white forehead patch.

Conclusion: We demonstrate significant phenotypic differences between Iberian Pied Flycatchers and Atlas Flycatchers with respect to size and traits of ecological and evolutionary relevance, supporting the recently proposed scenarios on their independent evolution.     

Promotion of flowering in azaleas by manipulating photoperiod and temperature induces epigenetic alterations during floral transition

The ability to control the timing of flowering is a key strategy for planning production in ornamental species such as the azalea; however, this requires a thorough understanding of floral induction pathways. DNA methylation is one of the main mechanisms involved in controlling the functional state of chromatin and gene expression in response to environmental and developmental signals. This work investigated the promotion of flowering in azaleas by the manipulation of environmental factors, using DNA methylation levels as a marker of floral bud development. The results showed that the change of long-day (LD) to short-day (SD) photoperiod is the primary factor responsible for floral induction in azaleas, whereas the existence of the previous cold period as well as the physiological memory are factors which improve floral production. Furthermore, for blooming to take place, 1300 units of growing degree days under an LD were necessary. The promotion of flowering in azaleas by alterations of photoperiod and temperature induced DNA methylation changes. The demethylation observed after the change from LD to SD is linked to a change in cell fate which is necessary for floral transition to take place and seems to be associated with the floral signal.     

Cell-to-Cell Transmission Can Overcome Multiple Donor and Target Cell Barriers Imposed on Cell-Free HIV

Virus transmission can occur either by a cell-free mode through the extracellular space or by cell-to-cell transmission involving direct cell-to-cell contact. The factors that determine whether a virus spreads by either pathway are poorly understood. Here, we assessed the relative contribution of cell-free and cell-to-cell transmission to the spreading of the human immunodeficiency virus (HIV). We demonstrate that HIV can spread by a cell-free pathway if all the steps of the viral replication cycle are efficiently supported in highly permissive cells. However, when the cell-free path was systematically hindered at various steps, HIV transmission became contact-dependent. Cell-to-cell transmission overcame barriers introduced in the donor cell at the level of gene expression and surface retention by the restriction factor tetherin. Moreover, neutralizing antibodies that efficiently inhibit cell-free HIV were less effective against cell-to-cell transmitted virus. HIV cell-to-cell transmission also efficiently infected target T cells that were relatively poorly susceptible to cell-free HIV. Importantly, we demonstrate that the donor and target cell types influence critically the extent by which cell-to-cell transmission can overcome each barrier. Mechanistically, cell-to-cell transmission promoted HIV spread to more cells and infected target cells with a higher proviral content than observed for cell-free virus. Our data demonstrate that the frequently observed contact-dependent spread of HIV is the result of specific features in donor and target cell types, thus offering an explanation for conflicting reports on the extent of cell-to-cell transmission of HIV.     

P. falciparum: merozoite surface protein-8 peptides bind specifically to human erythrocytes

This work determined Plasmodium falciparum merozoite surface protein-8 (MSP-8) regions specifically binding to membrane surface receptors on human erythrocytes. Five high activity binding peptides (HABPs), whose binding to erythrocytes became saturable and sensitive on being treated with neuraminidase and chymotrypsin were identified from the MSP-8 protein. Those amino acids directly involved in interaction with erythrocytes were also determined for each one of the HABPs. Some of them specifically recognized 28, 46, and 73 kDa erythrocyte membrane proteins. Some HABPs inhibited in vitro P. falciparum merozoite invasion of erythrocytes by up to 98%, suggesting the MSP-8 protein's possible role in the invasion process.