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81.
By shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms’ distribution patterns and understand their underlying drivers. Here we examine distributions of Pseudomonas in and around 15 human homes, focusing on the P. putida and P. fluorescens species groups. We describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. We collected a mean of 141 samples per visit, from sites in most rooms of the house, from the surrounding yards, and from human and pet occupants. We recovered Pseudomonas in 9.7% of samples, with the majority of isolates being from the P. putida and P. fluorescens species groups (approximately 62% and 23% of Pseudomonas samples recovered respectively). Although representatives of both groups were recovered from every season, every house, and every type of environment sampled, recovery was highly variable across houses and samplings. Whereas recovery of P. putida group was higher in summer and fall than in winter and spring, P. fluorescens group isolates were most often recovered in spring. P. putida group recovery from soils was substantially higher than its recovery from all other environment types, while higher P. fluorescens group recovery from soils than from other sites was much less pronounced. Both species groups were recovered from skin and upper respiratory tract samples from healthy humans and pets, although this occurred infrequently. This study indicates that even species that are able to survive under a broad range of conditions can be rare and variable in their distributions in space and in time. For such groups, determining patterns and causes of stochastic and seasonal variability may be more important for understanding the processes driving their biogeography than the identity of the types of environments in which they can be found. 相似文献
82.
Blanda Di Luccia Raffaella Crescenzo Arianna Mazzoli Luisa Cigliano Paola Venditti Jean-Claude Walser Alex Widmer Loredana Baccigalupi Ezio Ricca Susanna Iossa 《PloS one》2015,10(8)
A fructose-rich diet can induce metabolic syndrome, a combination of health disorders that increases the risk of diabetes and cardiovascular diseases. Diet is also known to alter the microbial composition of the gut, although it is not clear whether such alteration contributes to the development of metabolic syndrome. The aim of this work was to assess the possible link between the gut microbiota and the development of diet-induced metabolic syndrome in a rat model of obesity. Rats were fed either a standard or high-fructose diet. Groups of fructose-fed rats were treated with either antibiotics or faecal samples from control rats by oral gavage. Body composition, plasma metabolic parameters and markers of tissue oxidative stress were measured in all groups. A 16S DNA-sequencing approach was used to evaluate the bacterial composition of the gut of animals under different diets. The fructose-rich diet induced markers of metabolic syndrome, inflammation and oxidative stress, that were all significantly reduced when the animals were treated with antibiotic or faecal samples. The number of members of two bacterial genera, Coprococcus and Ruminococcus, was increased by the fructose-rich diet and reduced by both antibiotic and faecal treatments, pointing to a correlation between their abundance and the development of the metabolic syndrome. Our data indicate that in rats fed a fructose-rich diet the development of metabolic syndrome is directly correlated with variations of the gut content of specific bacterial taxa. 相似文献
83.
Siri T?htinen Saija Kaikkonen Maiju Merisalo-Soikkeli Susanna Gr?nberg-V?h?-Koskela Anna Kanerva Suvi Parviainen Markus V?h?-Koskela Akseli Hemminki 《PloS one》2015,10(6)
Unfavorable ratios between the number and activation status of effector and suppressor immune cells infiltrating the tumor contribute to resistance of solid tumors to T-cell based therapies. Here, we studied the capacity of FDA and EMA approved recombinant cytokines to manipulate this balance in favor of efficient anti-tumor responses in B16.OVA melanoma bearing C57BL/6 mice. Intratumoral administration of IFN-α2, IFN-γ, TNF-α, and IL-2 significantly enhanced the anti-tumor effect of ovalbumin-specific CD8+ T-cell (OT-I) therapy, whereas GM-CSF increased tumor growth in association with an increase in immunosuppressive cell populations. None of the cytokines augmented tumor trafficking of OT-I cells significantly, but injections of IFN-α2, IFN-γ and IL-2 increased intratumoral cytokine secretion and recruitment of endogenous immune cells capable of stimulating T-cells, such as natural killer and maturated CD11c+ antigen-presenting cells. Moreover, IFN-α2 and IL-2 increased the levels of activated tumor-infiltrating CD8+ T-cells concomitant with reduction in the CD8+ T-cell expression of anergy markers CTLA-4 and PD-1. In conclusion, intratumoral administration of IFN-α2, IFN-γ and IL-2 can lead to immune sensitization of the established tumor, whereas GM-CSF may contribute to tumor-associated immunosuppression. The results described here provide rationale for including local administration of immunostimulatory cytokines into T-cell therapy regimens. One appealing embodiment of this would be vectored delivery which could be advantageous over direct injection of recombinant molecules with regard to efficacy, cost, persistence and convenience. 相似文献
84.
Francesco Infarinato Anisur Rahman Claudio Del Percio Yves Lamberty Regis Bordet Jill C. Richardson Gianluigi Forloni Wilhelmus Drinkenburg Susanna Lopez Fabienne Aujard Claudio Babiloni Fabien Pifferi IMI project "PharmaCog" Consortium 《PloS one》2015,10(11)
The gray mouse lemur (Microcebus murinus) is considered a useful primate model for translational research. In the framework of IMI PharmaCog project (Grant Agreement n°115009, www.pharmacog.org), we tested the hypothesis that spectral electroencephalographic (EEG) markers of motor and locomotor activity in gray mouse lemurs reflect typical movement-related desynchronization of alpha rhythms (about 8–12 Hz) in humans. To this aim, EEG (bipolar electrodes in frontal cortex) and electromyographic (EMG; bipolar electrodes sutured in neck muscles) data were recorded in 13 male adult (about 3 years) lemurs. Artifact-free EEG segments during active state (gross movements, exploratory movements or locomotor activity) and awake passive state (no sleep) were selected on the basis of instrumental measures of animal behavior, and were used as an input for EEG power density analysis. Results showed a clear peak of EEG power density at alpha range (7–9 Hz) during passive state. During active state, there was a reduction in alpha power density (8–12 Hz) and an increase of power density at slow frequencies (1–4 Hz). Relative EMG activity was related to EEG power density at 2–4 Hz (positive correlation) and at 8–12 Hz (negative correlation). These results suggest for the first time that the primate gray mouse lemurs and humans may share basic neurophysiologic mechanisms of synchronization of frontal alpha rhythms in awake passive state and their desynchronization during motor and locomotor activity. These EEG markers may be an ideal experimental model for translational basic (motor science) and applied (pharmacological and non-pharmacological interventions) research in Neurophysiology. 相似文献
85.
Kemajittra Jenjaroen Suchintana Chumseng Manutsanun Sumonwiriya Pitchayanant Ariyaprasert Narisara Chantratita Piyanate Sunyakumthorn Maliwan Hongsuwan Vanaporn Wuthiekanun Helen A. Fletcher Prapit Teparrukkul Direk Limmathurotsakul Nicholas P. J. Day Susanna J. Dunachie 《PLoS neglected tropical diseases》2015,9(10)
Background
Melioidosis is an increasingly recognised cause of sepsis and death across South East Asia and Northern Australia, caused by the bacterium Burkholderia pseudomallei. Risk factors include diabetes, alcoholism and renal disease, and a vaccine targeting at-risk populations is urgently required. A better understanding of the protective immune response in naturally infected patients is essential for vaccine design.Methods
We conducted a longitudinal clinical and immunological study of 200 patients with melioidosis on admission, 12 weeks (n = 113) and 52 weeks (n = 65) later. Responses to whole killed B. pseudomallei were measured in peripheral blood mononuclear cells (PBMC) by interferon-gamma (IFN-γ) ELIspot assay and flow cytometry and compared to those of control subjects in the region with diabetes (n = 45) and without diabetes (n = 43).Results
We demonstrated strong CD4+ and CD8+ responses to B. pseudomallei during acute disease, 12 weeks and 52 weeks later. 28-day mortality was 26% for melioidosis patients, and B. pseudomallei-specific cellular responses in fatal cases (mean 98 IFN-γ cells per million PBMC) were significantly lower than those in the survivors (mean 142 IFN-γ cells per million PBMC) in a multivariable logistic regression model (P = 0.01). A J-shaped curve association between circulating neutrophil count and mortality was seen with an optimal count of 4000 to 8000 neutrophils/μl.Melioidosis patients with known diabetes had poor diabetic control (median glycated haemoglobin HbA1c 10.2%, interquartile range 9.2–13.1) and showed a stunted B. pseudomallei-specific cellular response during acute illness compared to those without diabetes.Conclusions
The results demonstrate the role of both CD4+ and CD8+ T-cells in protection against melioidosis, and an interaction between diabetes and cellular responses. This supports development of vaccine strategies that induce strong T-cell responses for the control of intracellular pathogens such as B. pseudomallei. 相似文献86.
Clara Braian Mattias Svensson Susanna Brighenti Maria Lerm Venkata R. Parasa 《Journal of visualized experiments : JoVE》2015,(104)
Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M. tuberculosis). The 3D tissue model consists of tissue-specific epithelial cells and fibroblasts, which are cultured in a matrix of collagen on top of a porous membrane. Upon air exposure, the epithelial cells stratify and secrete mucus at the apical side. By introducing human primary macrophages infected with M. tuberculosis to the tissue model, we have shown that immune cells migrate into the infected-tissue and form early stages of TB granuloma. These structures recapitulate the distinct feature of human TB, the granuloma, which is fundamentally different or not commonly observed in widely used experimental animal models. This organotypic culture method enables the 3D visualization and robust quantitative analysis that provides pivotal information on spatial and temporal features of host cell-pathogen interactions. Taken together, the lung tissue model provides a physiologically relevant tissue micro-environment for studies on TB. Thus, the lung tissue model has potential implications for both basic mechanistic and applied studies. Importantly, the model allows addition or manipulation of individual cell types, which thereby widens its use for modelling a variety of infectious diseases that affect the lungs. 相似文献
87.
88.
Seema Singh Susanna A. Braus-Stromeyer Christian Timpner Van Tuan Tran Gertrud Lohaus Michael Reusche Jessica Knüfer Thomas Teichmann Andreas von Tiedemann Gerhard H. Braus 《Applied microbiology and biotechnology》2010,85(6):1961-1976
The first leaky auxotrophic mutant for aromatic amino acids of the near-diploid fungal plant pathogen Verticillium longisporum (VL) has been generated. VL enters its host Brassica napus through the roots and colonizes the xylem vessels. The xylem contains little nutrients including low concentrations of amino
acids. We isolated the gene Vlaro2 encoding chorismate synthase by complementation of the corresponding yeast mutant strain. Chorismate synthase produces the
first branch point intermediate of aromatic amino acid biosynthesis. A novel RNA-mediated gene silencing method reduced gene
expression of both isogenes by 80% and resulted in a bradytrophic mutant, which is a leaky auxotroph due to impaired expression
of chorismate synthase. In contrast to the wild type, silencing resulted in increased expression of the cross-pathway regulatory
gene VlcpcA (similar to cpcA/GCN4) during saprotrophic life. The mutant fungus is still able to infect the host plant B. napus and the model Arabidopsis thaliana with reduced efficiency. VlcpcA expression is increased in planta in the mutant and the wild-type fungus. We assume that xylem colonization requires induction
of the cross-pathway control, presumably because the fungus has to overcome imbalanced amino acid supply in the xylem. 相似文献
89.
90.
Magda Gioia Giovanni Francesco Fasciglione Susanna Monaco Riccardo Iundusi Diego Sbardella Stefano Marini Umberto Tarantino Massimo Coletta 《Journal of biological inorganic chemistry》2010,15(8):1219-1232
The proteolytic processing of collagen I by three matrix metalloproteinases (MMPs), a collagenase (MMP-1), a gelatinase (MMP-2),
and the ectodomain of a membrane-type metalloproteinase (MMP-14), has been investigated at 37 °C between pH 6.0 and 9.2, a
pH range reflecting conditions found in different body compartments under various physiopathological processes. In the proteolytic
degradation the native collagen triple helix must be partially unwound to allow the binding of α chains to the protease’s
active-site cleft. We have found that MMP-1 interacts with the two types of collagen I α chains in a similar fashion, whereas
both MMP-2 and MMP-14 bind the two α chains in a different way. The overall enzymatic activity is higher on the α-2 chain
for both MMP-1 and MMP-2, whereas the MMP-14 ectodomain preferentially cleaves the α-1 chain. In MMP-2 a marked difference
for substrate affinity (higher for the α-1 chain) is overwhelmed by an even more marked propensity to cleave the α-2 chain.
As a whole, the three classes of MMPs investigated appear to process collagen I in a significantly different fashion, so various
MMPs play different roles in the collagen homeostasis in various compartments (such as bloodstream, synovial fluid, normal
and tumoral tissues), where different pH values are observed. 相似文献