The Epidemiology of Mould Infections in Argentina: Review and Experience

During the last decades, there has been an increasing proportion of patients susceptible to invasive fungal disease (IFD). The epidemiology of IFD varies mainly due to geography, antifungal exposure, and nosocomial reservoirs. We reviewed the Argentinean epidemiology of invasive mold disease (IMD) by analyzing laboratory and clinical data. Invasive mold disease was the second most prevalent IFD following the yeasts, with a prevalence that ranged from 0.98 to 1.31/100,000 population. The majority (60?C85?%) of IMD was caused by hyalohyphomycetes followed by Mucorales (6?C21?%) and phaeohyphomycetes (7?C13?%). The most prevalent genera were Aspergillus (40?C67?% of IMD) followed by Fusarium (10?C14?%). The most prevalent species were A. fumigatus (38?C50?%) followed by A. flavus (27?C43?%). In immunocompromised patients in Argentina the most prevalent agents of IMD are Aspergillus, followed by Fusarium and Mucorales, while the most prevalent Aspergillus species are A. fumigatus followed by A. flavus.     

Satellite surface reflectance improves habitat distribution mapping: a case study on heath and shrub formations in the Cantabrian Mountains (NW Spain)

Aim We aim to map the distribution of four heath and shrub formations constituting habitats of high conservation priority in Europe, whose occurrence is strongly dependent on human activities. Specifically, we assess whether the use of LANDSAT data in habitat distribution modelling may account for land use management, allowing accurate mapping of real distribution patterns. In particular, we explore whether reflectance values may be a better alternative to other remote sensing data traditionally used in modelling approaches (i.e. spectral vegetation indices and classified land cover maps). Finally, we test whether modelling performance is affected by the ecological traits of the dominant species of the target formations. Location Cantabrian Mountains (NW Spain). Methods We generated maps for the four formations (two specialists vs. two generalists) using MaxEnt. First, we ran the models with environmental predictors only (topography, climate, lithology and human disturbances). Then, we compared the advantages of including, in turn, different data derived from LANDSAT imagery: reflectance values (corresponding to different wavelength channels of the multispectral image), a spectral index and a land cover map. We assessed changes in explanatory power and also in the formation’s predicted distribution patterns. Results Formations dominated by specialist species were accurately mapped on a base of environmental variables only, whereas those dominated by generalists were overpredicted. Average mean temperature, southness and distance to urban areas were the variables contributing most in predictions of environmental models. LANDSAT channels increased the accuracy of all models, but mainly those for formations dominated by generalist species. They showed advantages against other remote sensing data traditionally used in modelling approaches. Main conclusions Habitat distribution models allowed accurate mapping of heath and shrub formations. The use of reflectance values as predictors improved the accuracy of the models, particularly for formations dominated by generalist species, supplying environmental information that was otherwise unavailable.     

Phylogenetic analysis of four nuclear protein-encoding genes largely corroborates the traditional classification of Bivalvia (Mollusca)

Revived interest in molluscan phylogeny has resulted in a torrent of molecular sequence data from phylogenetic, mitogenomic, and phylogenomic studies. Despite recent progress, basal relationships of the class Bivalvia remain contentious, owing to conflicting morphological and molecular hypotheses. Marked incongruity of phylogenetic signal in datasets heavily represented by nuclear ribosomal genes versus mitochondrial genes has also impeded consensus on the type of molecular data best suited for investigating bivalve relationships. To arbitrate conflicting phylogenetic hypotheses, we evaluated the utility of four nuclear protein-encoding genes-ATP synthase β, elongation factor-1α, myosin heavy chain type II, and RNA polymerase II-for resolving the basal relationships of Bivalvia. We sampled all five major lineages of bivalves (Archiheterodonta, Euheterodonta [including Anomalodesmata], Palaeoheterodonta, Protobranchia, and Pteriomorphia) and inferred relationships using maximum likelihood and Bayesian approaches. To investigate the robustness of the phylogenetic signal embedded in the data, we implemented additional datasets wherein length variability and/or third codon positions were eliminated. Results obtained include (a) the clade (Nuculanida+Opponobranchia), i.e., the traditionally defined Protobranchia; (b) the monophyly of Pteriomorphia; (c) the clade (Archiheterodonta+Palaeoheterodonta); (d) the monophyly of the traditionally defined Euheterodonta (including Anomalodesmata); and (e) the monophyly of Heteroconchia, i.e., (Palaeoheterodonta+Archiheterodonta+Euheterodonta). The stability of the basal tree topology to dataset manipulation is indicative of signal robustness in these four genes. The inferred tree topology corresponds closely to those obtained by datasets dominated by nuclear ribosomal genes (18S rRNA and 28S rRNA), controverting recent taxonomic actions based solely upon mitochondrial gene phylogenies.     

Production of Fibronectin Binding Protein A at the Surface of Lactococcus lactis Increases Plasmid Transfer In Vitro and In Vivo

Lactococci are noninvasive lactic acid bacteria frequently used as protein delivery vectors and, more recently, as DNA delivery vehicles. We previously showed that Lactococcus lactis (LL) expressing the Fibronectin-Binding Protein A of Staphylococcus aureus (LL-FnBPA+) showed higher internalization rates in vitro in Caco-2 cells than the native (wt) lactococci and were able to deliver a eukaryotic Green Fluorescent Protein (GFP) expression plasmid in 1% of human Caco-2 cells. Here, using the bovine beta-lactoglobulin (BLG), one of the major cow''s milk allergen, and GFP we characterized the potential of LL-FnBPA+ as an in vivo DNA vaccine delivery vehicle. We first showed that the invasive strain LL-FnBPA+ carrying the plasmid pValac:BLG (LL-FnBPA+ BLG) was more invasive than LL-BLG and showed the same invasivity as LL-FnBPA+. Then we demonstrated that the Caco-2 cells, co-incubated with LL-FnBPA+ BLG produced up to 30 times more BLG than the Caco-2 cells co-incubated with the non invasive LL-BLG. Using two different gene reporters, BLG and GFP, and two different methods of detection, EIA and fluorescence microscopy, we showed in vivo that: i) in order to be effective, LL-FnBPA+ required a pre-coating with Fetal Calf Serum before oral administration; ii) plasmid transfer occurred in enterocytes without regard to the strains used (invasive or not); iii) the use of LL-FnBPA+ increased the number of mice producing BLG, but not the level of BLG produced. We thus confirmed the good potential of invasive recombinant lactic acid bacteria as DNA delivery vector in vivo.     

Salmon aquaculture and antimicrobial resistance in the marine environment

Antimicrobials used in salmon aquaculture pass into the marine environment. This could have negative impacts on marine environmental biodiversity, and on terrestrial animal and human health as a result of selection for bacteria containing antimicrobial resistance genes. We therefore measured the numbers of culturable bacteria and antimicrobial-resistant bacteria in marine sediments in the Calbuco Archipelago, Chile, over 12-month period at a salmon aquaculture site approximately 20 m from a salmon farm and at a control site 8 km distant without observable aquaculture activities. Three antimicrobials extensively used in Chilean salmon aquaculture (oxytetracycline, oxolinic acid, and florfenicol) were studied. Although none of these antimicrobials was detected in sediments from either site, traces of flumequine, a fluoroquinolone antimicrobial also widely used in Chile, were present in sediments from both sites during this period. There were significant increases in bacterial numbers and antimicrobial-resistant fractions to oxytetracycline, oxolinic acid, and florfenicol in sediments from the aquaculture site compared to those from the control site. Interestingly, there were similar numbers of presumably plasmid-mediated resistance genes for oxytetracycline, oxolinic acid and florfenicol in unselected marine bacteria isolated from both aquaculture and control sites. These preliminary findings in one location may suggest that the current use of large amounts of antimicrobials in Chilean aquaculture has the potential to select for antimicrobial-resistant bacteria in marine sediments.     

Flagella from Five Cronobacter Species Induce Pro-Inflammatory Cytokines in Macrophage Derivatives from Human Monocytes

Cronobacter spp. are opportunistic pathogens linked to lie-threatening infections in neonates and contaminated powdered infant formula that has been epidemiologically associated with these cases. Clinical symptoms of Cronobacter include necrotizing enterocolitis, bacteremia, and meningitis. Flagella from C. sakazakii are involved in biofilm formation and its adhesion to epithelial cells. We investigated the role of flagella from C. sakazakii ST1 and ST4, C. malonaticus, C. muytjensii, C. turicensis and C. dublinensis during the activation of cytokines (IL-8, TNF-α, and IL-10) in macrophage derivatives from human monocytes, which has not been extensively studied. The production and identity of flagella from the five Cronobacter species were visualized and recognized with anti-flagella antibodies by immunogold labeling through transmission electron microscopy. Purified flagella were dissociated into monomers in 12% SDS-PAGE Coomassie blue-stained gels showing a band of ∼28 kDa and, in addition, mass spectrometry revealed the presence of several peptides that correspond to flagellin. Flagella (100 ng) induced the release of IL-8 (3314–6025 pg/ml), TNF-α (39–359 pg/ml), and IL-10 (2–96 pg/ml), in macrophage isolates from human monocytes and similar results were obtained when flagella were dissociated into monomers. Inhibition assays using three dilutions of anti-flagella antibodies (1∶10, 1∶100, and 1∶200) suppressed the secretion of IL-8, TNF-α, and IL-10 between 95–100% using 100 ng of protein. A transfection assay using 293-hTLR5 cells showed IL-8 release of 197 pg/ml and suppression in the secretion of IL-8 when anti-hTLR5-IgA antibodies were used at different concentrations. These observations suggest that flagella and flagellin are involved in an inflammatory response dependent on TLR5 recognition, which could contribute to the pathogenesis of the bacteria.     

Lithocholic acid extends longevity of chronologically aging yeast only if added at certain critical periods of their lifespan

Our studies revealed that LCA (lithocholic bile acid) extends yeast chronological lifespan if added to growth medium at the time of cell inoculation. We also demonstrated that longevity in chronologically aging yeast is programmed by the level of metabolic capacity and organelle organization that they developed before entering a quiescent state and, thus, that chronological aging in yeast is likely to be the final step of a developmental program progressing through at least one checkpoint prior to entry into quiescence. Here, we investigate how LCA influences longevity and several longevity-defining cellular processes in chronologically aging yeast if added to growth medium at different periods of the lifespan. We found that LCA can extend longevity of yeast under CR (caloric restriction) conditions only if added at either of two lifespan periods. One of them includes logarithmic and diauxic growth phases, whereas the other period exists in early stationary phase. Our findings suggest a mechanism linking the ability of LCA to increase the lifespan of CR yeast only if added at either of the two periods to its differential effects on various longevity-defining processes. In this mechanism, LCA controls these processes at three checkpoints that exist in logarithmic/diauxic, post-diauxic and early stationary phases. We therefore hypothesize that a biomolecular longevity network progresses through a series of checkpoints, at each of which (1) genetic, dietary and pharmacological anti-aging interventions modulate a distinct set of longevity-defining processes comprising the network; and (2) checkpoint-specific master regulators monitor and govern the functional states of these processes.     

N-3 Long-Chain Polyunsaturated Fatty Acid Supplementation Significantly Reduces Liver Oxidative Stress in High Fat Induced Steatosis

Omega-3 (n-3) long-chain polyunsaturated fatty acids (n-3 LCPUFA) are associated with several physiological functions, suggesting that their administration may prevent non transmissible chronic diseases. Therefore, we investigate whether dietary n-3 LCPUFA supplementation triggers an antioxidant response preventing liver steatosis in mice fed a high fat diet (HFD) in relation to n-3 LCPUFA levels. Male C57BL/6J mice received (a) control diet (10% fat, 20% protein, 70% carbohydrate), (b) control diet plus n-3 LCPUFA (108 mg/kg/day eicosapentaenoic acid plus 92 mg/kg/day docosahexaenoic acid), (c) HFD (60% fat, 20% protein, 20% carbohydrate), or (d) HFD plus n-3 LCPUFA for 12 weeks. Parameters of liver steatosis, glutathione status, protein carbonylation, and fatty acid analysis were determined, concomitantly with insulin resistance and serum tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 levels. HFD significantly increased total fat and triacylglyceride contents with macrovesicular steatosis, concomitantly with higher fasting serum glucose and insulin levels, HOMA, and serum TNF-α, IL-1β, and IL-6. Reduced and total liver glutathione contents were diminished by HFD, with higher GSSG/GSH ratio and protein carbonylation, n-3 LCPUFA depletion and elevated n-6/n-3 ratio over control values. These changes were either reduced or normalized to control values in animals subjected to HFD and n-3 LCPUFA, with significant increased hepatic total n-3 LCPUFA content and reduced n-6/n-3 ratio being observed after n-3 LCPUFA supplementation alone. So, repletion of liver n-3 LCPUFA levels by n-3 LCPUFA dietary supplementation in HFD obese mice reduces hepatic lipid content, with concomitant antioxidant and anti-inflammatory responses favouring insulin sensitivity.