cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.7492016.v1
title: O-specific polysaccharide confers lysozyme resistance to extraintestinal pathogenic <i>Escherichia coli</i>

description: Extraintestinal pathogenic <i>Escherichia coli</i> (ExPEC) is the leading cause of bloodstream and other extraintestinal infections in human and animals. The greatest challenge encountered by ExPEC during an infection is posed by the host defense mechanisms, including lysozyme. ExPEC have developed diverse strategies to overcome this challenge. The aim of this study was to characterize the molecular mechanism of ExPEC resistance to lysozyme. For this, 15,000 transposon mutants of a lysozyme-resistant ExPEC strain NMEC38 were screened; 20 genes were identified as involved in ExPEC resistance to lysozyme—of which five were located in the gene cluster between <i>galF</i> and <i>gnd</i>, and were further confirmed to be involved in O-specific polysaccharide biosynthesis. The O-specific polysaccharide was able to inhibit the hydrolytic activity of lysozyme; it was also required by the complete lipopolysaccharide (LPS)-mediated protection of ExPEC against the bactericidal activity of lysozyme. The O-specific polysaccharide was further shown to be able to directly interact with lysozyme. Furthermore, LPS from ExPEC strains of different O serotypes was also able to inhibit the hydrolytic activity of lysozyme. Because of their cell surface localization and wide distribution in Gram-negative bacteria, O-specific polysaccharides appear to play a long-overlooked role in protecting bacteria against exogenous lysozyme.
DOI: 10.6084/m9.figshare.7492016.v2
title: O-specific polysaccharide confers lysozyme resistance to extraintestinal pathogenic <i>Escherichia coli</i>

description: Extraintestinal pathogenic <i>Escherichia coli</i> (ExPEC) is the leading cause of bloodstream and other extraintestinal infections in human and animals. The greatest challenge encountered by ExPEC during an infection is posed by the host defense mechanisms, including lysozyme. ExPEC have developed diverse strategies to overcome this challenge. The aim of this study was to characterize the molecular mechanism of ExPEC resistance to lysozyme. For this, 15,000 transposon mutants of a lysozyme-resistant ExPEC strain NMEC38 were screened; 20 genes were identified as involved in ExPEC resistance to lysozyme—of which five were located in the gene cluster between <i>galF</i> and <i>gnd</i>, and were further confirmed to be involved in O-specific polysaccharide biosynthesis. The O-specific polysaccharide was able to inhibit the hydrolytic activity of lysozyme; it was also required by the complete lipopolysaccharide (LPS)-mediated protection of ExPEC against the bactericidal activity of lysozyme. The O-specific polysaccharide was further shown to be able to directly interact with lysozyme. Furthermore, LPS from ExPEC strains of different O serotypes was also able to inhibit the hydrolytic activity of lysozyme. Because of their cell surface localization and wide distribution in Gram-negative bacteria, O-specific polysaccharides appear to play a long-overlooked role in protecting bacteria against exogenous lysozyme.
DOI: 10.6084/m9.figshare.7492028.v2
title: <i>Helicobacter suis</i> binding to carbohydrates on human and porcine gastric mucins and glycolipids occurs via two modes

description: <i>Helicobacter suis</i> colonizes the stomach of most pigs and is the most prevalent non-<i>Helicobacter pylori</i> Helicobacter species found in the human stomach. In the human host, <i>H. suis</i> contributes to the development of chronic gastritis, peptic ulcer disease and MALT lymphoma, whereas in pigs it is associated with gastritis, decreased growth and ulcers. Here, we demonstrate that the level of <i>H. pylori</i> and <i>H. suis</i> binding to human and pig gastric mucins varies between individuals with species dependent specificity. The binding optimum of <i>H. pylori</i> is at neutral pH whereas that of <i>H. suis</i> has an acidic pH optimum, and the mucins that <i>H. pylori</i> bind to are different than those that <i>H. suis</i> bind to. Mass spectrometric analysis of mucin <i>O</i>-glycans from the porcine mucin showed that individual variation in binding is reflected by a difference in glycosylation; of 109 oligosaccharide structures identified, only 14 were present in all examined samples. <i>H. suis</i> binding to mucins correlated with glycans containing sulfate, sialic acid and terminal galactose. Among the glycolipids present in pig stomach, binding to lactotetraosylceramide (Galβ3GlcNAcβ3Galβ4Glcβ1Cer) was identified, and adhesion to Galβ3GlcNAcβ3Galβ4Glc at both acidic and neutral pH was confirmed using other glycoconjugates. Together with that <i>H. suis</i> bound to DNA (used as a proxy for acidic charge), we conclude that <i>H. suis</i> has two binding modes: one to glycans terminating with Galβ3GlcNAc, and one to negatively charged structures. Identification of the glycan structures <i>H. suis</i> interacts with can contribute to development of therapeutic strategies alternative to antibiotics.
DOI: 10.6084/m9.figshare.7491938
title: Pneumonia infection in mice reveals the involvement of the <i>feoA</i> gene in the pathogenesis of <i>Acinetobacter baumannii</i>

description: <i>Acinetobacter baumannii</i> has emerged in the last decade as an important nosocomial pathogen. To identify genes involved in the course of a pneumonia infection, gene expression profiles were obtained from <i>A. baumannii</i> ATCC 17978 grown in mouse infected lungs and in culture medium. Gene expression analysis allowed us to determine a gene, the A1S_0242 gene (<i>feoA</i>), over-expressed during the pneumonia infection. In the present work, we evaluate the role of this gene, involved in iron uptake. The inactivation of the A1S_0242 gene resulted in an increase susceptibility to oxidative stress and a decrease in biofilm formation, in adherence to A549 cells and in fitness. In addition, infection of <i>G. mellonella</i> and pneumonia in mice showed that the virulence of the Δ0242 mutant was significantly attenuated. Data presented in this work indicated that the A1S_0242 gene from <i>A. baumannii</i> ATCC 17978 strain plays a role in fitness, adhesion, biofilm formation, growth, and, definitively, in virulence. Taken together, these observations show the implication of the <i>feoA</i> gene plays in the pathogenesis of <i>A. baumannii</i> and highlight its value as a potential therapeutic target.
DOI: 10.6084/m9.figshare.7491938.v1
title: Pneumonia infection in mice reveals the involvement of the <i>feoA</i> gene in the pathogenesis of <i>Acinetobacter baumannii</i>

description: <i>Acinetobacter baumannii</i> has emerged in the last decade as an important nosocomial pathogen. To identify genes involved in the course of a pneumonia infection, gene expression profiles were obtained from <i>A. baumannii</i> ATCC 17978 grown in mouse infected lungs and in culture medium. Gene expression analysis allowed us to determine a gene, the A1S_0242 gene (<i>feoA</i>), over-expressed during the pneumonia infection. In the present work, we evaluate the role of this gene, involved in iron uptake. The inactivation of the A1S_0242 gene resulted in an increase susceptibility to oxidative stress and a decrease in biofilm formation, in adherence to A549 cells and in fitness. In addition, infection of <i>G. mellonella</i> and pneumonia in mice showed that the virulence of the Δ0242 mutant was significantly attenuated. Data presented in this work indicated that the A1S_0242 gene from <i>A. baumannii</i> ATCC 17978 strain plays a role in fitness, adhesion, biofilm formation, growth, and, definitively, in virulence. Taken together, these observations show the implication of the <i>feoA</i> gene plays in the pathogenesis of <i>A. baumannii</i> and highlight its value as a potential therapeutic target.
DOI: 10.6084/m9.figshare.7492028
title: <i>Helicobacter suis</i> binding to carbohydrates on human and porcine gastric mucins and glycolipids occurs via two modes

description: <i>Helicobacter suis</i> colonizes the stomach of most pigs and is the most prevalent non-<i>Helicobacter pylori</i> Helicobacter species found in the human stomach. In the human host, <i>H. suis</i> contributes to the development of chronic gastritis, peptic ulcer disease and MALT lymphoma, whereas in pigs it is associated with gastritis, decreased growth and ulcers. Here, we demonstrate that the level of <i>H. pylori</i> and <i>H. suis</i> binding to human and pig gastric mucins varies between individuals with species dependent specificity. The binding optimum of <i>H. pylori</i> is at neutral pH whereas that of <i>H. suis</i> has an acidic pH optimum, and the mucins that <i>H. pylori</i> bind to are different than those that <i>H. suis</i> bind to. Mass spectrometric analysis of mucin <i>O</i>-glycans from the porcine mucin showed that individual variation in binding is reflected by a difference in glycosylation; of 109 oligosaccharide structures identified, only 14 were present in all examined samples. <i>H. suis</i> binding to mucins correlated with glycans containing sulfate, sialic acid and terminal galactose. Among the glycolipids present in pig stomach, binding to lactotetraosylceramide (Galβ3GlcNAcβ3Galβ4Glcβ1Cer) was identified, and adhesion to Galβ3GlcNAcβ3Galβ4Glc at both acidic and neutral pH was confirmed using other glycoconjugates. Together with that <i>H. suis</i> bound to DNA (used as a proxy for acidic charge), we conclude that <i>H. suis</i> has two binding modes: one to glycans terminating with Galβ3GlcNAc, and one to negatively charged structures. Identification of the glycan structures <i>H. suis</i> interacts with can contribute to development of therapeutic strategies alternative to antibiotics.
DOI: 10.6084/m9.figshare.7492028.v1
title: <i>Helicobacter suis</i> binding to carbohydrates on human and porcine gastric mucins and glycolipids occurs via two modes

description: <i>Helicobacter suis</i> colonizes the stomach of most pigs and is the most prevalent non-<i>Helicobacter pylori</i> Helicobacter species found in the human stomach. In the human host, <i>H. suis</i> contributes to the development of chronic gastritis, peptic ulcer disease and MALT lymphoma, whereas in pigs it is associated with gastritis, decreased growth and ulcers. Here, we demonstrate that the level of <i>H. pylori</i> and <i>H. suis</i> binding to human and pig gastric mucins varies between individuals with species dependent specificity. The binding optimum of <i>H. pylori</i> is at neutral pH whereas that of <i>H. suis</i> has an acidic pH optimum, and the mucins that <i>H. pylori</i> bind to are different than those that <i>H. suis</i> bind to. Mass spectrometric analysis of mucin <i>O</i>-glycans from the porcine mucin showed that individual variation in binding is reflected by a difference in glycosylation; of 109 oligosaccharide structures identified, only 14 were present in all examined samples. <i>H. suis</i> binding to mucins correlated with glycans containing sulfate, sialic acid and terminal galactose. Among the glycolipids present in pig stomach, binding to lactotetraosylceramide (Galβ3GlcNAcβ3Galβ4Glcβ1Cer) was identified, and adhesion to Galβ3GlcNAcβ3Galβ4Glc at both acidic and neutral pH was confirmed using other glycoconjugates. Together with that <i>H. suis</i> bound to DNA (used as a proxy for acidic charge), we conclude that <i>H. suis</i> has two binding modes: one to glycans terminating with Galβ3GlcNAc, and one to negatively charged structures. Identification of the glycan structures <i>H. suis</i> interacts with can contribute to development of therapeutic strategies alternative to antibiotics.
DOI: 10.6084/m9.figshare.7491968
title: Extracellular vesicles and vesicle-free secretome of the protozoa <i>Acanthamoeba castellanii</i> under homeostasis and nutritional stress and their damaging potential to host cells

description: <i>Acanthamoeba castellanii</i> (<i>Ac</i>) are ubiquitously distributed in nature, and by contaminating medical devices such as heart valves and contact lenses, they cause a broad range of clinical presentations to humans. Although several molecules have been described to play a role in Ac pathogenesis, including parasite host-tissue invasion and escaping of host-defense, little information is available on their mechanisms of secretion. Herein, we describe the molecular components secreted by Ac, under different protein availability conditions to simulate host niches. <i>Ac</i> extracellular vesicles (EVs) were morphologically and biochemically characterized. Dynamic light scattering analysis of <i>Ac</i> EVs identified polydisperse populations, which correlated to electron microscopy measurements. High-performance thin liquid chromatography of <i>Ac</i> EVs identified phospholipids, steryl-esters, sterol and free-fatty acid, the last two also characterized by GC-MS. Secretome composition (EVs and EVs-free supernatants) was also determined and proteins biological functions classified. In peptone-yeast-glucose (PYG) medium, a total of 179 proteins were identified (21 common proteins, 89 exclusive of EVs and 69 in EVs-free supernatant). In glucose alone, 205 proteins were identified (134 in EVs, 14 common and 57 proteins in EVs-free supernatant). From those, stress response, oxidative and protein and amino acid metabolism proteins prevailed. Qualitative differences were observed on carbohydrate metabolism enzymes from Krebs cycle and pentose phosphate shunt. Serine proteases and metalloproteinases predominated. Analysis of the cytotoxicity of Ac EVs (upon uptake) and EVs-free supernatant to epithelial and glioblastoma cells revealed a dose-dependent effect. Therefore, the Ac secretome differs depending on nutrient conditions, and is also likely to vary during infection.
DOI: 10.6084/m9.figshare.7491968.v2
title: Extracellular vesicles and vesicle-free secretome of the protozoa <i>Acanthamoeba castellanii</i> under homeostasis and nutritional stress and their damaging potential to host cells

description: <i>Acanthamoeba castellanii</i> (<i>Ac</i>) are ubiquitously distributed in nature, and by contaminating medical devices such as heart valves and contact lenses, they cause a broad range of clinical presentations to humans. Although several molecules have been described to play a role in Ac pathogenesis, including parasite host-tissue invasion and escaping of host-defense, little information is available on their mechanisms of secretion. Herein, we describe the molecular components secreted by Ac, under different protein availability conditions to simulate host niches. <i>Ac</i> extracellular vesicles (EVs) were morphologically and biochemically characterized. Dynamic light scattering analysis of <i>Ac</i> EVs identified polydisperse populations, which correlated to electron microscopy measurements. High-performance thin liquid chromatography of <i>Ac</i> EVs identified phospholipids, steryl-esters, sterol and free-fatty acid, the last two also characterized by GC-MS. Secretome composition (EVs and EVs-free supernatants) was also determined and proteins biological functions classified. In peptone-yeast-glucose (PYG) medium, a total of 179 proteins were identified (21 common proteins, 89 exclusive of EVs and 69 in EVs-free supernatant). In glucose alone, 205 proteins were identified (134 in EVs, 14 common and 57 proteins in EVs-free supernatant). From those, stress response, oxidative and protein and amino acid metabolism proteins prevailed. Qualitative differences were observed on carbohydrate metabolism enzymes from Krebs cycle and pentose phosphate shunt. Serine proteases and metalloproteinases predominated. Analysis of the cytotoxicity of Ac EVs (upon uptake) and EVs-free supernatant to epithelial and glioblastoma cells revealed a dose-dependent effect. Therefore, the Ac secretome differs depending on nutrient conditions, and is also likely to vary during infection.
DOI: 10.6084/m9.figshare.7491968.v1
title: Extracellular vesicles and vesicle-free secretome of the protozoa <i>Acanthamoeba castellanii</i> under homeostasis and nutritional stress and their damaging potential to host cells

description: <i>Acanthamoeba castellanii</i> (<i>Ac</i>) are ubiquitously distributed in nature, and by contaminating medical devices such as heart valves and contact lenses, they cause a broad range of clinical presentations to humans. Although several molecules have been described to play a role in Ac pathogenesis, including parasite host-tissue invasion and escaping of host-defense, little information is available on their mechanisms of secretion. Herein, we describe the molecular components secreted by Ac, under different protein availability conditions to simulate host niches. <i>Ac</i> extracellular vesicles (EVs) were morphologically and biochemically characterized. Dynamic light scattering analysis of <i>Ac</i> EVs identified polydisperse populations, which correlated to electron microscopy measurements. High-performance thin liquid chromatography of <i>Ac</i> EVs identified phospholipids, steryl-esters, sterol and free-fatty acid, the last two also characterized by GC-MS. Secretome composition (EVs and EVs-free supernatants) was also determined and proteins biological functions classified. In peptone-yeast-glucose (PYG) medium, a total of 179 proteins were identified (21 common proteins, 89 exclusive of EVs and 69 in EVs-free supernatant). In glucose alone, 205 proteins were identified (134 in EVs, 14 common and 57 proteins in EVs-free supernatant). From those, stress response, oxidative and protein and amino acid metabolism proteins prevailed. Qualitative differences were observed on carbohydrate metabolism enzymes from Krebs cycle and pentose phosphate shunt. Serine proteases and metalloproteinases predominated. Analysis of the cytotoxicity of Ac EVs (upon uptake) and EVs-free supernatant to epithelial and glioblastoma cells revealed a dose-dependent effect. Therefore, the Ac secretome differs depending on nutrient conditions, and is also likely to vary during infection.
DOI: 10.6084/m9.figshare.21792245
title: Effects of vitamin D supplementation on carotid intima-media thickness in HIV-infected youth

description: Effects of vitamin D supplementation on carotid intima-media thickness in HIV-infected youth
DOI: 10.6084/m9.figshare.21792245.v1
title: Effects of vitamin D supplementation on carotid intima-media thickness in HIV-infected youth

description: Effects of vitamin D supplementation on carotid intima-media thickness in HIV-infected youth
DOI: 10.6084/m9.figshare.6887369
title: Autophagy enhances the replication of Peste des petits ruminants virus and inhibits caspase-dependent apoptosis in vitro

description: Peste des petits ruminants (PPR) is an acute and highly contagious disease in small ruminants that causes significant economic losses in developing countries. An increasing number of studies have demonstrated that both autophagy and apoptosis are important cellular mechanisms for maintaining homeostasis, and they participate in the host response to pathogens. However, the crosstalk between apoptosis and autophagy in host cells during PPRV infection has not been clarified. In this study, autophagy was induced upon virus infection in caprine endometrial epithelial cells (EECs), as determined by the appearance of double- and single-membrane autophagy-like vesicles, LC3-I/LC3-II conversion, and p62 degradation. We also found that PPRV infection triggered a complete autophagic response, most likely mediated by the non-structural protein C and nucleoprotein N. Moreover, our results suggest that autophagy not only promotes the replication of PPRV in EECs but also provides a potential mechanism for inhibiting PPRV-induced apoptosis. Inhibiting autophagosome formation by wortmannin and knocking down the essential autophagic proteins Beclin-1 and ATG7 induces caspase-dependent apoptosis in EECs in PPRV infection. However, inhibiting autophagosome and lysosome fusion by NH<sub>4</sub>Cl and chloroquine did not increase the number of apoptotic cells. Collectively, these data are the first to indicate that PPRV-induced autophagy inhibits caspase-dependent apoptosis and thus contributes to the enhancement of viral replication and maturity in host cells.
DOI: 10.6084/m9.figshare.6887369.v1
title: Autophagy enhances the replication of Peste des petits ruminants virus and inhibits caspase-dependent apoptosis in vitro

description: Peste des petits ruminants (PPR) is an acute and highly contagious disease in small ruminants that causes significant economic losses in developing countries. An increasing number of studies have demonstrated that both autophagy and apoptosis are important cellular mechanisms for maintaining homeostasis, and they participate in the host response to pathogens. However, the crosstalk between apoptosis and autophagy in host cells during PPRV infection has not been clarified. In this study, autophagy was induced upon virus infection in caprine endometrial epithelial cells (EECs), as determined by the appearance of double- and single-membrane autophagy-like vesicles, LC3-I/LC3-II conversion, and p62 degradation. We also found that PPRV infection triggered a complete autophagic response, most likely mediated by the non-structural protein C and nucleoprotein N. Moreover, our results suggest that autophagy not only promotes the replication of PPRV in EECs but also provides a potential mechanism for inhibiting PPRV-induced apoptosis. Inhibiting autophagosome formation by wortmannin and knocking down the essential autophagic proteins Beclin-1 and ATG7 induces caspase-dependent apoptosis in EECs in PPRV infection. However, inhibiting autophagosome and lysosome fusion by NH<sub>4</sub>Cl and chloroquine did not increase the number of apoptotic cells. Collectively, these data are the first to indicate that PPRV-induced autophagy inhibits caspase-dependent apoptosis and thus contributes to the enhancement of viral replication and maturity in host cells.
DOI: 10.6084/m9.figshare.6887057
title: <i>Galleria mellonella -</i> a novel infection model for the <i>Mycobacterium tuberculosis</i> complex

description: Animal models have long been used in tuberculosis research to understand disease pathogenesis and to evaluate novel vaccine candidates and anti-mycobacterial drugs. However, all have limitations and there is no single animal model which mimics all the aspects of mycobacterial pathogenesis seen in humans. Importantly mice, the most commonly used model, do not normally form granulomas, the hallmark of tuberculosis infection. Thus there is an urgent need for the development of new alternative <i>in vivo</i> models. The insect larvae, <i>Galleria mellonella</i> has been increasingly used as a successful, simple, widely available and cost-effective model to study microbial infections. Here we report for the first time that <i>G. mellonella</i> can be used as an infection model for members of the <i>Mycobacterium tuberculosis</i> complex. We demonstrate a dose-response for <i>G. mellonella</i> survival infected with different inocula of bioluminescent <i>Mycobacterium bovis</i> BCG <i>lux</i>, and demonstrate suppression of mycobacterial luminesence over 14 days. Histopathology staining and transmission electron microscopy of infected <i>G. mellonella</i> phagocytic haemocytes show internalization and aggregation of <i>M. bovis</i> BCG <i>lux</i> in granuloma-like structures, and increasing accumulation of lipid bodies within <i>M. bovis</i> BCG <i>lux</i> over time, characteristic of latent tuberculosis infection. Our results demonstrate <i>that G. mellonella</i> can act as a surrogate host to study the pathogenesis of mycobacterial infection and shed light on host-mycobacteria interactions, including latent tuberculosis infection.