Characterization of the gene encoding pisatin demethylase (FoPDA1) in Fusarium oxysporum

The pea pathogen Fusarium oxysporum f. sp. pisi is able to detoxify pisatin produced as a defense response by pea, and the gene encoding this detoxification mechanism, FoPDA1, was 82% identical to the cytochrome P450 pisatin demethylase PDA1 gene in Nectria haematococca. A survey of F. oxysporum f. sp. pisi isolates demonstrated that, as in N. haematococca, the PDA gene of F. oxysporum f. sp. pisi is generally located on a small chromosome. In N. haematococca, PDA1 is in a cluster of pea pathogenicity (PEP) genes. Homologs of these PEP genes also were found in the F. oxysporum f. sp. pisi isolates, and PEP1 and PEP5 were sometimes located on the same small chromosomes as the FoPDA1 homologs. Transforming FoPDA1 into a pda(?) F. oxysporum f. sp. lini isolate conferred pda activity and promoted pathogenicity on pea to some transformants. Different hybridization patterns of FoPDA1 were found in F. oxysporum f. sp. pisi but these did not correlate with the races of the fungus, suggesting that races within this forma specialis arose independently of FoPDA1. FoPDA1 also was present in the formae speciales lini, glycines, and dianthi of F. oxysporum but they had mutations resulting in nonfunctional proteins. However, an active FoPDA1 was present in F. oxysporum f. sp. phaseoli and it was virulent on pea. Despite their evolutionary distance, the amino acid sequences of FoPDA1 of F. oxysporum f. sp. pisi and F. oxysporum f. sp. phaseoli revealed only six amino acid differences, consistent with a horizontal gene transfer event accounting for the origin of these genes.     

Latitudinal Variation in Starvation Resistance is Explained by Lipid Content in Natural Populations of Drosophila melanogaster

One of the most common environmental stressors is a shortage or suboptimal quality of food, thus all animals deal with periods of starvation. In the present study we examine variation in starvation resistance, longevity and body lipid content and the correlations between traits along an environmental gradient using isofemale lines recently derived from natural populations of Drosophila melanogaster from South America. The use of isofemale lines and controlled rearing laboratory conditions allows us to investigate within and among population components of genetic variation and the potential associations among starvation resistance, longevity and body lipid content. All these traits were analyzed separately in females and males, improving our understanding of sexual dimorphism. Our results revealed significant differences among populations in starvation resistance and longevity. Actually, the opposing latitudinal cline detected for starvation resistance suggests that natural selection played an essential role in shaping the pattern of geographic variation in this trait. Moreover, we also detected a positive relationship between starvation resistance and body lipid content in both sexes, providing evidence for a physiological and/or evolutionary association between these traits. Conversely, starvation resistance was not correlated with longevity indicating that these traits might be enabled to evolve independently. Finally, our study reveals that there is abundant within population genetic variation for all traits that may be maintained by sex-specific effects.     

Assessing the effects of habitat characteristics and co-occurrence with closely related species on occupancy of resident ‘wood-warblers’ in a Neotropical working landscape

The simultaneous effects of habitat traits and interspecific interactions determine the occurrence and habitat use of wildlife populations. However, little research has been devoted to examining spatial co-occurrence among closely related species while considering the effect of habitat variation and imperfect detectability of species in the field. In this study, we focused on migratory and resident 'wood-warblers' that coexist during the winter in a Neotropical working landscape in southern Mexico to understand if habitat occupancy of resident wood-warblers is influenced by habitat characteristics and by the presence of other species of resident and migratory wood-warblers. For this purpose, we implemented two-species occupancy models, which account for the imperfect detectability of these birds in the field. Our results revealed that habitat occupancy of resident wood-warblers was positively influenced by the presence of other closely related species (both migratory and resident). These positive relationships may be explained by the fact that different species of wood-warblers frequently participate in mixed-species flocks. However, these patterns of species co-occurrence were more evident among resident species than between migratory and resident species, which may be explained by micro-habitat segregation and differences in behaviours between resident and migratory wood-warblers. We also found that some habitat characteristics may mediate the observed patterns of species co-occurrence. Specifically, sites with larger trees were associated with the co-occurrence of some species of resident wood-warblers. In addition, we discuss the possibility that species co-occurrence might be the result of shared preferences for environmental factors that we did not consider. Our study highlights the importance of the interplay between species co-occurrence and habitat traits in determining the presence and habitat use of resident birds in Neotropical working landscapes.     

Persistent Release of IL-1s from Skin Is Associated with Systemic Cardio-Vascular Disease,Emaciation and Systemic Amyloidosis: The Potential of Anti-IL-1 Therapy for Systemic Inflammatory Diseases

The skin is an immune organ that contains innate and acquired immune systems and thus is able to respond to exogenous stimuli producing large amount of proinflammatory cytokines including IL-1 and IL-1 family members. The role of the epidermal IL-1 is not limited to initiation of local inflammatory responses, but also to induction of systemic inflammation. However, association of persistent release of IL-1 family members from severe skin inflammatory diseases such as psoriasis, epidermolysis bullosa, atopic dermatitis, blistering diseases and desmoglein-1 deficiency syndrome with diseases in systemic organs have not been so far assessed. Here, we showed the occurrence of severe systemic cardiovascular diseases and metabolic abnormalities including aberrant vascular wall remodeling with aortic stenosis, cardiomegaly, impaired limb and tail circulation, fatty tissue loss and systemic amyloid deposition in multiple organs with liver and kidney dysfunction in mouse models with severe dermatitis caused by persistent release of IL-1s from the skin. These morbid conditions were ameliorated by simultaneous administration of anti-IL-1α and IL-1β antibodies. These findings may explain the morbid association of arteriosclerosis, heart involvement, amyloidosis and cachexia in severe systemic skin diseases and systemic autoinflammatory diseases, and support the value of anti-IL-1 therapy for systemic inflammatory diseases.     

Cytomegalovirus Vaccine Strain Towne-Derived Dense Bodies Induce Broad Cellular Immune Responses and Neutralizing Antibodies That Prevent Infection of Fibroblasts and Epithelial Cells

Human cytomegalovirus (HCMV), a betaherpesvirus, can cause severe disease in immunosuppressed patients and following congenital infection. A vaccine that induces both humoral and cellular immunity may be required to prevent congenital infection. Dense bodies (DBs) are complex, noninfectious particles produced by HCMV-infected cells and may represent a vaccine option. As knowledge of the antigenicity and immunogenicity of DB is incomplete, we explored characterization methods and defined DB production methods, followed by systematic evaluation of neutralization and cell-mediated immune responses to the DB material in BALB/c mice. DBs purified from Towne-infected cultures treated with the viral terminase inhibitor 2-bromo-5,6-dichloro-1-beta-d-ribofuranosyl benzimidazole riboside (BDCRB) were characterized by nanoparticle tracking analysis (NTA), two-dimensional fluorescence difference gel electrophoresis (2D-DIGE), immunoblotting, quantitative enzyme-linked immunosorbent assay, and other methods. The humoral and cellular immune responses to DBs were compared to the immunogenicity of glycoprotein B (gB) administered with the adjuvant AddaVax (gB/AddaVax). DBs induced neutralizing antibodies that prevented viral infection of cultured fibroblasts and epithelial cells and robust cell-mediated immune responses to multiple viral proteins, including pp65, gB, and UL48. In contrast, gB/AddaVax failed to induce neutralizing antibodies that prevented infection of epithelial cells, highlighting a critical difference in the humoral responses induced by these vaccine candidates. Our data advance the potential for the DB vaccine approach, demonstrate important immunogenicity properties, and strongly support the further evaluation of DBs as a CMV vaccine candidate.     

Categorization of humans in biomedical research: genes,race and disease

A debate has arisen regarding the validity of racial/ethnic categories for biomedical and genetic research. Some claim 'no biological basis for race' while others advocate a 'race-neutral' approach, using genetic clustering rather than self-identified ethnicity for human genetic categorization. We provide an epidemiologic perspective on the issue of human categorization in biomedical and genetic research that strongly supports the continued use of self-identified race and ethnicity.     

Effects of different stressor agents on gilthead seabream natural cytotoxic activity

Several common situations in gilthead seabream (Sparus aurata L.) farming, such as air exposure, crowding and the use of anaesthetics, have been demonstrated to be stressful. In the present study, these conditions were simulated in the laboratory, after which head-kidney natural cytotoxic cell (NCC) activity was evaluated. For this, several specimens were air exposed for 2 min, returned to the aquarium and sampled from 0 to 4 days after exposure. NCC activity was significantly lower on the day following air-exposure compared with the control (rested fish) but not at any other time studied. Other fish were crowded (100 kg biomass m(-3), 2 h), returned to an aquarium with the same density as the control group (9 kg m(-3)) and sampled from 0 to 4 days after treatment. Head-kidney NCC activity was statistically increased compared with the control (resting) fish, 1 day after crowding. Anaesthesis for 1 h with 60 or 200 microl 2-phenoxyethanol l(-1)had no significant effect on NCC activity, while the use of 50 mg MS222 l(-1)for 1 h reduced such activity (by about 40%) compared with the control. In other experiments, fish were consecutively treated with crowding and anaesthetics. When treated with the lowest 2-phenoxyethanol concentration after crowding, the NCC activity inhibition was abolished compared with the activity in fish treated either with crowding or anaesthetic alone, while the use of the highest concentration increased such inhibition. The use of MS222 after crowding did not produce any differential effect compared with the fish treated with only one of the factors. In conclusion, NCC activity is affected differently according to the stress factor applied (hypoxia, crowding and/or anaesthetics). Differences in the effects provoked by these stressors on other seabream innate immune parameters are discussed.     

The hairpin ribozyme substrate binding-domain: a highly constrained D-shaped conformation

The two domains of the hairpin ribozyme-substrate complex, usually depicted as straight structural elements, must interact with one another in order to form an active conformation. Little is known about the internal geometry of the individual domains in an active docked complex. Using various crosslinking and structural approaches in conjunction with molecular modeling (constraint-satisfaction program MC-SYM), we have investigated the conformation of the substrate-binding domain in the context of the active docked ribozyme-substrate complex. The model generated by MC-SYM showed that the domain is not straight but adopts a bent conformation (D-shaped) in the docked state of the ribozyme, indicating that the two helices bounding the internal loop are closer than was previously assumed. This arrangement rationalizes the observed ability of hairpin ribozymes with a circularized substrate-binding strand to cleave a circular substrate, and provides essential information concerning the organization of the substrate in the active conformation. The internal geometry of the substrate-binding strand places G8 of the substrate-binding strand near the cleavage site, which has allowed us to predict the crucial role played by this nucleotide in the reaction chemistry.     

Physical factors driving intertidal macroalgae distribution: physiological stress of a dominant fucoid at its southern limit

Climate change is driving species range shifts worldwide. However, physiological responses related to distributional changes are not fully understood. Oceanographers have reported an increase in ocean temperature in the northwest Iberian Peninsula that is potentially related to the decline in some cold-temperate intertidal macroalgae in the Cantabrian Sea, namely Fucus serratus. Low tide stress could also play a role in this decline. We performed one mensurative (in situ) and two manipulative (in culture) experiments designed to evaluate the interactive effects of some physical factors. The first experiment analysed field response to low tide stress in marginal (mid-Cantabrian Sea and northern Portugal) versus central (Galicia) populations of F. serratus. Then a second experiment was performed that utilized either harsh or mild summer conditions of atmospheric temperature, irradiance, humidity, and wind velocity to compare the responses of individuals from one marginal and one central population to low tide stress. Finally, the combined effect of sea temperature and the other factors was evaluated to detect interactive effects. Changes in frond growth, maximal photosynthetic quantum yield (F (v)/F (m)), temperature, and desiccation were found. Three additive factors (solar irradiation, ocean and air temperatures) were found to drive F. serratus distribution, except under mildly humid conditions that ameliorated atmospheric thermal stress (two additive factors). Mid-Cantabrian Sea temperatures have recently increased, reaching the inhibitory levels suggested in this study of F. serratus. We also expect an additive secondary contribution of low tide stress to this species decline. On the northern Portugal coast, ocean warming plus low tide stress has not reached this species' inhibition threshold. No significant differential responses attributed to the population of origin were found. Mechanistic approaches that are designed to analyse the interactive effects of physical stressors may improve the levels of confidence in predicted range shifts of species.