Judith Behnsen's research while affiliated with University of Illinois at Chicago and other places

Publications (41)

Article
Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causes of food-borne illnesses worldwide. To colonize the gastrointestinal tract, S. Typhimurium produces multiple virulence factors that facilitate cellular invasion. Chitinases have been recently emerging as virulence factors for various pathogenic bacterial species, a...
Preprint
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The fungal gut microbiota (mycobiota) has been implicated in diseases that disturb gut homeostasis. However, little is known about functional relationships between bacteria and fungi in the gut during infectious colitis. We investigated the role of fungal metabolites during infection with the intestinal pathogen Salmonella enterica serovar Typhimur...
Preprint
Full-text available
Salmonella enterica serovar Typhimurium ( Salmonella ) is one of the leading causes of food-borne illnesses worldwide. To colonize the gastrointestinal tract, Salmonella produces multiple virulence factors that facilitate cellular invasion. Chitinases have been recently emerging as virulence factors for various pathogenic bacterial species and the...
Article
Full-text available
Zinc is an essential cofactor for bacterial metabolism, and many Enterobacteriaceae express the zinc transporters ZnuABC and ZupT to acquire this metal in the host. However, the probiotic bacterium Escherichia coli Nissle 1917 (or “Nissle”) exhibits appreciable growth in zinc-limited media even when these transporters are deleted. Here, we show tha...
Article
Full-text available
The study of bacterial competition systems has received significant attention in recent years. These systems are important in a multitude of polymicrobial environments and collectively shape the composition of complex ecosystems like the mammalian gut.
Preprint
Many bacterial species encode systems for interference competition with other microorganisms. Some systems are effective without contact (e.g. through secretion of toxins), while other systems (e.g. Type VI secretion system (T6SS)) require direct contact between cells. Here, we provide the initial characterization of a novel contact-dependent compe...
Article
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The term “microbiota” invokes images of mucosal surfaces densely populated with bacteria. These surfaces and the luminal compartments they form indeed predominantly harbor bacteria. However, research from this past decade has started to complete the picture by focusing on important but largely neglected constituents of the microbiota: fungi, viruse...
Preprint
Full-text available
Zinc is an essential cofactor for bacterial metabolism, and many Enterobacteriaceae express the zinc transporters ZnuABC and ZupT to acquire this metal in the host. Unexpectedly, the probiotic bacterium Escherichia coli Nissle 1917 exhibited appreciable growth in zinc-limited media even when these transporters were deleted. By utilizing in vitro an...
Article
Commensal bacteria are known to provide colonization resistance in the gut. But exactly which ones provide this function? In a recent paper in Science, Kim et al. (2017) revealed that Clostridia added to mouse infant gut microbiota are sufficient to limit colonization of pathogenic Enterobacteriaceae.
Article
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Background: Obesity and inflammatory bowel disease (IBD) represent chronic inflammatory conditions. Bariatric surgery improves some obesity-related co-morbidities, but the effects of bariatric surgery on IBD have not been well studied. Objectives: To examine if bariatric surgery may attenuate colitis in an obese murine model of IBD and study the...
Article
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Siderophores are small molecular iron chelators that are produced by microbes and whose most notable function is to sequester iron from the host and provide this essential metal nutrient to microbes. Recent studies have proposed additional, noncanonical roles for siderophores, including the acquisition of noniron metals and modulation of host funct...
Article
Sodium phenylbutyrate (PBA) is a derivative of the short-chain fatty acid butyrate, and is approved for treatment of urea cycle disorders and progressive familial intrahepatic cholestasis type 2. Previously known functions include histone deacetylase inhibitor, endoplasmic reticulum stress inhibitor, ammonia sink, and chemical chaperone. Here we sh...
Article
Neutrophils hinder bacterial growth by a variety of antimicrobial mechanisms, including the production of reactive oxygen species and the secretion of proteins that sequester nutrients essential to microbes. A major player in this process is calprotectin, a host protein that exerts antimicrobial activity by chelating zinc and manganese. Here we sho...
Article
The intestinal mucosa is a particularly dynamic environment in which the host constantly interacts with trillions of commensal microorganisms, known as the microbiota, and periodically interacts with pathogens of diverse nature. In this Review, we discuss how mucosal immunity is controlled in response to enteric bacterial pathogens, with a focus on...
Article
Full-text available
Pathogens have evolved clever strategies to evade and in some cases exploit the attacks of an activated immune system. Salmonella enterica is one such pathogen, exploiting multiple aspects of host defense to promote its replication in the host. Here we review recent findings on the mechanisms by which Salmonella establishes systemic and chronic inf...
Article
Interleukin-22 (IL-22) is highly induced in response to infections with a variety of pathogens, and its main functions are considered to be tissue repair and host defense at mucosal surfaces. Here we showed that IL-22 has a unique role during infection in that its expression suppressed the intestinal microbiota and enhanced the colonization of a pa...
Article
In this issue of Immunity, Zelante et al. (2013) and Qiu et al. (2013) provide mechanistic insights into functional interactions between commensal microbes and innate lymphoid cells via the aryl hydrocarbon receptor.
Article
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Probiotics are beneficial components of the microbiota that have been used for centuries because of the health benefits they confer to the host. Only recently, however, has the contribution of probiotics to modulation of immunological, respiratory, and gastrointestinal functions started to be fully appreciated and scientifically evaluated. Probioti...
Article
The saprophytic fungus Aspergillus fumigatus is a mold which is ubiquitously present in the environment. It produces large numbers of spores, called conidia that we constantly inhale with the breathing air. Healthy individuals normally do not suffer from true fungal infections with this pathogen. A normally robust resistance against Aspergillus is...
Article
Phagocytosis of conidia by macrophages and destruction of hyphae by neutrophils are key processes in the defense against infections caused by filamentous fungi. Impairment in phagocytic function leads to increased susceptibility for an infection with Aspergillus species. The fact that a Th1-based immune response to an infection with Aspergillus spe...
Article
Full-text available
The opportunistic human pathogenic fungus Aspergillus fumigatus is a major cause of fungal infections in immunocompromised patients. Innate immunity plays an important role in the defense against infections. The complement system represents an essential part of the innate immune system. This cascade system is activated on the surface of A. fumigatu...
Article
Full-text available
The opportunistic human pathogenic fungus Aspergillus fumigatus causes severe systemic infections and is a major cause of fungal infections in immunocompromised patients. A. fumigatus conidia activate the alternative pathway of the complement system. In order to assess the mechanisms by which A. fumigatus evades the activated complement system, we...
Article
Full-text available
Author Summary Aspergillus fumigatus and Candida albicans are the most common of all human pathogenic fungal germs. Normally, inhaled Aspergillus spores are destroyed by alveolar macrophages and polymorphonuclear neutrophils (PMNs), both of which are lung phagocytes, i.e., cells that kill inhaled microbes by ingestion. In contrast, C. albicans is...
Data
J774 Cells with Conidia in Liquid Media An active J774 macrophage is seen taking up at least three conidia in a cooperative manner. The J774 cells were treated with 5 ng/ml interferon-γ one night before filming with conidia. The observation was made over a period of 2.5 h every 30 s. (2.9 MB AVI)
Data
Competitive Phagocytosis Assay in Collagen A neutrophil can be seen here selectively taking up Candida yeasts despite several contacts with A. fumigatus conidia in a 3-D collagen matrix. Imaging time was 2 h with an interval of 30 s after every frame. (2.6 MB AVI)
Data
Dendritic Cells with Conidia in Collagen A single DC can be seen here efficiently taking up at least four conidia in its vicinity. (5.4 MB AVI)
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Polymorphonuclear Cells with Conidia in Liquid Media A rapidly moving neutrophil can be seen taking up several conidia over an imaging time of 2 h with one frame every 30 s. (2.5 MB AVI)
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PMNs with Conidia in Collagen A PMN can be seen here touching a conidium and even displacing it, but eventually moving on without further interaction. Imaging time was 3 h with one frame every 30 s. (671 KB AVI)
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Dendritic Cells Dragging Conidia in Collagen A well resolved dendritic cell drags a conidium through a distance of up to 9 μm. The conidium, however, is not phagocytosed by the cell. The observation was made over 3 h with one frame every 30 s. (14.0 MB AVI)
Data
Alveolar Macrophages with Conidia in Liquid Medium Two highly active alveolar macrophages can be seen ingesting conidia. Time lapse is 30 s per frame over 2.5 h. (4.1 MB AVI)
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PMNs Dragging Conidia in Media Several neutrophils can be seen dragging clusters of conidia without actually phagocytosing them. A majority of conidia are attached to PMNs at the end of the video leading to the formation of an aggregate. Imaging time was 3 h with a time lapse of one frame every 30 s. (3.1 MB AVI)
Data
PMNs with C. albicans Yeasts in Collagen Neutrophils are seen here interacting with C. albicans in collagen matrix. In contrast to A. fumigatus conidia, most of the PMNs carry Candida, and a phagocytosis event can be seen at 142.5 min. (6.9 MB AVI)
Data
Competitive Phagocytosis Assay in Media A neutrophil is seen here with a heavy load of A. fumigatus conidia, which are dragged along with the cell. The PMN seems to selectively pick up conidia despite several contacts with Candida yeasts. The video was made over 2 h with a time lapse of one frame every 30 s. (6.9 MB AVI)
Data
RAW Macrophages with Yeasts in Collagen A few RAW macrophages can be seen here carrying Candida yeasts. A large yeast is taken up by a cell at 30 min and is pulled up towards the cell. The observation was made over a period of 2 h with one frame every 30 s. (1.6 MB AVI)
Data
Conidia Can Be Attached to the PMN Surface or Truly Internalized A 3-D reconstruction of a z stack showing a fixed preparation of a PMN carrying five conidia intracellularly and one on the surface. The actin cytoskeleton of the PMN is seen here in green, while the conidia are seen in red. (10.5 MB AVI)
Data
PMNs with C. albicans Yeasts in Liquid Media Neutrophils are not able to take up C. albicans yeasts despite several contacts in liquid media, in contrast to A. fumigatus conidia. In addition, no dragging of yeasts is visible here. (2.0 MB AVI)
Data
Dendritic Cells with Conidia in Media A single DC can be seen here interacting with conidia in liquid media and taking up two of them. The observation was made over a period of 3 h with a time lapse of 30 s. (6.2 MB AVI)
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RAW Macrophages with Yeasts in Media Like neutrophils, RAW macrophages as seen here are unable to take up yeasts despite contacts. Imaging time was 3 h with an interval of 30 s after each frame. (2.9 MB AVI)

Citations

... Glycans are the first point of contact for microbes, and they must penetrate O-linked mucins in mucous and the glycocalyx oligosaccharides to allow successful pathogen binding and cell entry. For instance, S. Typhimurium secretes chitinases and sialidases that target N-linked GlcNAc-containing glycans and sialic acid, respectively [60][61][62][63]. Gut microbes frequently target O-glycans such as mucin to disrupt mucous viscosity or to use as an energy source [64]. ...
... A number of other metallophore classes have been reported, including chalkophores (Cu), zincophores (Zn), molybdophores (Mo), nickelophores (Ni), and lanthanophores (lanthanides) [1,6]. Although siderophores are the most well-studied metallophores by a large margin, other metallophores play equally crucial roles in diverse natural environments and the human host [1,7,8]. The chemistry and biology of a metallophore is often highly specific [1,4,9], and thus biotechnological applications require an understanding of natural metallophore systems [5]. ...
... In contrast, Juarez et al. (2020) showed that volatile compounds produced by P. mirabilis (including ammonia) negatively affected the growth and biofilm formation of Klebsiella pneumoniae. Moreover, recent work showed that interspecies interactions between P. mirabilis and other Enterobacteriaceae may involve TVISS-independent, as yet unknown contact-dependent mechanisms (Kiani et al., 2021). Importantly, the interactions between P. mirabilis and other bacteria may also result in the acquisition of novel antibiotic resistance mechanisms through horizontal gene transfer (Bonnin et al., 2020). ...
... The human gut also harbors a large number of fungi, known as the gut mycobiome. The gut fungi have been demonstrated to be causally implicated in microbiome assembly, ecology, and immune development [196,197]. In the study of Zuo et al., patients with COVID-19 also presented with alterations in the gut mycobiome, characterized by enrichment of Candida albicans and highly heterogeneous mycobiome configurations [176]. ...
... tuberculosis), it decreases the mortality of mice infected with STm [32][33][34]. Under zinc-limiting conditions, the growth of E. coli Nissle 1917 did not weaken due to the deletion of zinc transporter genes, and the bacteria utilize yersiniabactin to scavenge zinc to resist calprotectin-mediated zinc sequestration in the inflamed gut [35]. The newly discovered TonB-dependent outer membrane protein receptor ZnuD in Neisseria meningitidis regulates the absorption of zinc and haem and can induce antibodies combined with vesicles to infect guinea pigs and activate complement-mediated cytotoxicity to kill bacteria [36,37]. ...
... Then, the increased Enterobacteriaceae abundance could induce neutrophil transepithelial migration and the depletion of SCFA-producing bacteria (e.g., Bifidobacteriaceae and Clostridia genera). Moreover, the depletion of SCFA-producing bacteria may inhibit their ability to limit the colonization of Enterobacteriaceae via intestinal pH reduction (Behnsen, 2017;Yoo et al., 2020), which is shown in Figure 6. ...
... Out of the 59 studies, 36 studies applied a pre-post design (baseline measurements provided) (Group 1: n = 23 ; Group 2: n = 10 [60][61][62][63][64][65][66][67][68][69]; Group 3: n = 4 [70][71][72][73]). Sixteen studies used a crosssectional design (Group 1: n = 6 [74][75][76][77][78][79]; Group 2: n = 10 [80][81][82][83][84][85][86][87][88][89]), whereas four studies applied a longitudinal study design with multiple measurement points postoperatively but without baseline measurements (Group 2 [90][91][92][93]). ...
... Exemplary of this co-evolutionary arms race are high-affinity iron-binding molecules known as siderophores (eg. enterobactin), secreted predominantly by gram-negative bacterial species to scavenge iron from their host (Behnsen and Raffatellu, 2016;Kramer et al., 2020). In turn, several host cells, including the airway epithelium, produce the immune mediator lipocalin-2 (Neutrophil-gelatinase associated lipocalin, NGAL), which binds iron-loaded enterobactin, rendering it inaccessible for bacterial uptake. ...
... SCFA has also been linked with inducing antimicrobial functions in different innate cells and inducing protection against various enteric pathogens. Butyrate exerts protective in vivo effects against S. Typhimurium and C. rodentium by inducing colonic macrophage antimicrobial responses (42,46). Similarly, butyrate-treated macrophages exhibited increased autophagic flux and autophagosome degradation of S. Typhimurium together with increased ROS activity (42). ...
... Some antimicrobial effectors such as Elafin (PI3), a small cationic peptide secreted at mucosal surfaces [18], Calprotectin (S100A8 and S100A9), Lipocalin-2 (N-GAL), and Beta-Defensin-2 (DEFB4) were produced at higher levels in PMN-HIOs, compared to HIOs alone. However, since Salmonella has evolved mechanisms to overcome Calprotectin-mediated immunity and thrive under these conditions; upregulation of these specific antimicrobial effectors is likely insufficient to reduce Salmonella colonization in the PMN-HIOs [19,20]. Collectively, these data support that PMNs can migrate into the lumen of the infected PMN-HIO, but do not reduce overall bacterial burden, which largely reflects luminal bacteria. ...