Martin Schwarzer

Institute of Microbiology of the Czech Academy of Sciences, Novy Hradek, Czech Republic · Laboratory of Gnotobiology

Escherichia coli A0 34/86 (EcO83) is a probiotic strain used in newborns to prevent nosocomial infections and diarrhoea. This bacterium stimulates both pro‐ and anti‐inflammatory cytokine production and its intranasal administration reduces allergic airway inflammation in mice. Despite its benefits, there are concerns about the use of live probioti...

Allergies have become a growing problem and the number of cases is increasing yearly. Administration of postbiotics, well-defined bacterial molecules, is gaining attention as a novel and promising strategy to ameliorate the allergic burden. The BAP1 polysaccharide (PS) of Bifidobacterium adolescentis CCDM 368, was previously characterized by us reg...

The alarming prevalence of inflammatory bowel disease (IBD) in early childhood is associated with imbalances in the microbiome, the immune response, and environmental factors. Some pathogenic Escherichia coli (E. coli) strains have been found in IBD patients, where they may influence disease progression. Therefore, the discovery of new harmful bact...

Type 1 Diabetes (T1D) is a chronic disease caused by autoimmune destruction of insulin-producing pancreatic β-cells. The insulin B-chain 9-23 (insB:9-23) peptide is established as a critical epitope in triggering T1D. In our previous study, we showed that Parabacteroides distasonis , a human gut commensal, contains an insB:9-23 mimic in its hprt pr...

Intestinal epithelial cells have the capacity to upregulate MHCII molecules in response to certain epithelial-adhesive microbes, such as segmented filamentous bacteria (SFB). However, the mechanism regulating MHCII expression as well as the impact of epithelial MHCII–mediated antigen presentation on T cell responses targeting those microbes remains...

The currently observed high prevalence of allergic diseases has been associated with changes in microbial exposure in industrialized countries. Defined bacterial components represent a new strategy for modulating the allergic immune response. We show that intranasal administration of exopolysaccharide isolated from Lacticaseibacillus (L.) rhamnosus...

PRRSV is capable of evading the effective immune response, thus persisting in piglets and throughout the swine herd. We show here that PRRSV invades the thymus and causes depletion of T-cell precursors and alteration of the TCR repertoire. Developing thymocytes are affected during negative selection when they transit from the triple-negative to tri...

Bifidobacteria are among the most common bacteria used for their probiotic properties and their impact on the maturation and function of the immune system has been well-described. Recently, scientific interest is shifting from live bacteria to defined bacteria-derived biologically active molecules. Their greatest advantage over probiotics is the de...

The ability of hyaluronan as a dietary supplement to increase skin moisture and relieve knee pain has been demonstrated in several clinical studies. To understand the mechanism of action, determining hyaluronan's bioavailability and in vivo fate is crucial. Here, we used 13C-hyaluronan combined with LC–MS analysis to compare the absorption and meta...

The intestinal microbiota is known to influence postnatal growth. We previously found that a strain of Lactiplantibacillus plantarum (strain LpWJL) buffers the adverse effects of chronic undernutrition on the growth of juvenile germ-free mice. Here, we report that LpWJL sustains the postnatal growth of malnourished conventional animals and supports...

IL-17 protects epithelial barriers by inducing the secretion of antimicrobial peptides (AMPs). However, the effect of IL-17 on Paneth cells (PCs), the major producers of AMPs in the small intestine, is unclear. Here, we show that targeted ablation of the IL-17 receptor (IL-17R) in PCs disrupts their antimicrobial functions and decreases the frequen...

Background Animals form complex symbiotic associations with their gut microbes, whose evolution is determined by an intricate network of host and environmental factors. In many insects, such as Drosophila melanogaster , the microbiome is flexible, environmentally determined, and less diverse than in mammals. In contrast, mammals maintain complex mu...

Background: Nearly 45% of deaths among children under 5 years of age are related to undernutrition. Protein-energy malnutrition (PEM) is accompanied by underweight (low weight for age), stunting (low height for age), and wasting (low weight for height). Bacteriotherapy is considered as a promising complementary therapy to refeeding for ameliorating...

Mature T cells are selected for recognizing self-antigens with low to intermediate affinity in the thymus. Recently, the relative differences in self-reactivity among individual T-cell clones were appreciated as important factors regulating their fate and immune response, but the role of self-reactivity in T-cell biology is incompletely understood....

Bifidobacteria are gram-positive, anaerobic or microaerophilic bacteria, which also include strains with proven probiotic activity. The positive effect of probiotic bacteria on the host is well known. Probiotic strains of Bifidobacteria have the ability to modulate the immune system through components of the cell wall, such as peptidoglycan, polysa...

The expression of MHCII by intestinal epithelial cells (IEC) determines the severity of intestinal immunopathological reactions. However, the function of MHCII on IEC under homeostatic conditions remains elusive. Here we report that MHCII expression on IECs is a hallmark of an adaptive wave of homeostatic intestinal immune responses to commensal se...

INTRODUCTION Due to their health-promoting properties, bacteria of the Bifidobacterium genus are commonly used as probiotics. Not only do they impact the general well-being of the host, but they are also crucial for the maturation of the immune system and the creation of immune system responses. However, the use of the whole bacteria causes the bod...

An average human child stop breastfeeding after six months of birth. Children do not get a proper protein diet in underdeveloped and developing countries. To mirror this situation. We challenge mice with a PEM diet at early weaning age and test or prove the therapeutic potential of LpWJL. We fed mice orally with LpWJL, results demonstrated in this...

Bifidobacterium strains are well known for their health-promoting properties. However, the exact effect on the host results from the composition and metabolic activity of the studied bacteria. Moreover, the immunomodulatory properties of the Bifidobacterium molecules may differ between antigens. This is why thorough studies are needed to reveal a b...

Animals form complex symbiotic associations with their gut microbes, whose evolution is determined by an intricate network of host and environmental factors. In many insects, such as Drosophila melanogaster , the microbiome is flexible, environmentally determined and less diverse than in mammals. In contrast, mammals maintain complex multispecies c...

Mus musculus is the classic mammalian model for biomedical research. Despite global efforts to standardize breeding and experimental procedures, the undefined composition and interindividual diversity of the microbiota of laboratory mice remains a limitation. In an attempt to standardize the gut microbiome in preclinical mouse studies, here we repo...

The classical definition of probiotics states that bacteria must be alive to be beneficial for human organism. However, recent reports show that inactivated bacteria or their effector molecules can also possess such properties. In this study, we investigated the physical and immunomodulatory properties of four Bifidobacterium strains in the heat-tr...

A steady rise in the number of poly-sensitized patients has increased the demand for effective prophylactic strategies against multi-sensitivities. Probiotic bacteria have been successfully used in clinics and experimental models to prevent allergic mono-sensitization. In the present study, we have investigated whether probiotic bacteria could prev...

The use of probiotics is now widely practiced due to their beneficial effect on health and their relative safety status. Research shows that oral administration of probiotics such as Bifidobacterium to allergy sufferers can alleviate symptoms and prevent relapse in patients with allergic rhinitis (1). Recently, intranasal administration of probioti...

Numerous studies indicate the beneficial effect of the human gut microbiota on the health and proper functioning of the host (O'Callaghan A., van Sinderen D.; 2016). One of the main representatives of the gastrointestinal tract belongs to the gram-positive, anaerobic Bifidobacterium genus, whose immunomodulatory properties have already been confirm...

A variety of health benefits has been documented to be associated with the consumption of probiotic bacteria, namely bifidobacteria and lactobacilli. Thanks to the scientific advances in recent years we are beginning to understand the molecular mechanisms by which bacteria in general and probiotic bacteria in particular act as host physiology and i...

Chronic undernutrition leads to growth hormone resistance and poor growth in children, which has been shown to be modulated by microbiota. We studied whether Lactobacillus fermentum CECT5716 (Lf CECT5716), isolated from mother’s breast milk, could promote juvenile growth through the modulation of lipid absorption in a model of starvation. Germ-free...

The Oligo-Mouse-Microbiota (OMM¹²) is a recently developed synthetic bacterial community for functional microbiome research in mouse models (Brugiroux et al., 2016). To date, the OMM¹² model has been established in several germ-free mouse facilities world-wide and is employed to address a growing variety of research questions related to infection b...

Mus musculus is the classic mammalian model for biomedical research. Despite global efforts in standardizing breeding and experimental procedures, the undefined nature and inter-individual diversity of laboratory mouse microbiota remains a limitation. In an attempt to standardize preclinical studies, we have developed a simplified mouse microbiota...

Significant efforts are necessary to introduce new dietary protein sources to feed a growing world population while maintaining food supply chain sustainability. Such a sustainable protein transition includes the use of highly modified proteins from side streams or the introduction of new protein sources that may lead to increased clinically releva...

Background: Mucosal mast cells (MC) are key players in IgE-mediated food allergy (FA). The evidence on the interaction between gut microbiota, MC and susceptibility to FA is contradictory. Objective: We tested the hypothesis that commensal bacteria are essential for MC migration to the gut and their maturation impacting the susceptibility to FA. Me...

Background: Mucosal mast cells (MC) are key players in IgE-mediated food allergy (FA). The evidence on the interaction between gut microbiota, MC and susceptibility to FA is contradictory. Objective: We tested the hypothesis that commensal bacteria are essential for MC migration to the gut and their maturation impacting the susceptibility to FA. Me...

In most animal species, postnatal growth is controlled by conserved insulin/insulin-like growth factor (IGF) signaling. In mammals, juvenile growth is characterized by a longitudinal bone growth resulting from the ossification of the growth plate. This ossification is under IGF1 influence through endocrine and paracrine mechanisms. Moreover, the nu...

Good genes, good food, good friends. That is what parents hope will sustain and nurture the harmonious growth of their children. The impact of the genetic background and nutrition on postnatal growth has been in the spot light for long, but the good friends have come to the scene only recently. Among the good friends perhaps the most crucial ones a...

Background Chronic undernutrition, a condition currently affecting more than 17 millions of children under five years of age, has severe long-term consequences including stunting. Epidemiologic studies have emphasized that undernutrition cannot be ascribed to food insecurity alone and gut microbiota has been shown to play an active role in disease...

List of all the compounds detected in axenic poor yeast diet, and in poor yeast diet inoculated with L. plantarumWJL, after a 3-day incubation period. The list displays the relative levels of each compound in a diet inoculated with L. plantarumWJL compared with an axenic diet.

List of all the compounds detected in axenic niche (poor yeast diet + larva), and in niche inoculated with L. plantarumWJL, after a 3-day incubation period. The list displays the relative levels of each compound, in a niche inoculated with L. plantarumWJL compared with an axenic niche.

List of all the compounds detected in live and dead larvae excreta. The list displays the relative levels of each compound in excreta of live larvae compared with excreta of dead larvae.

Purpose of review: This review focuses on the recent discoveries about the impact of intestinal microbiota on mammalian host juvenile growth. Recent findings: Intestinal microbiota is a powerful modulator of many facets of multicellular host's physiology. Recent results from human field studies and animal research have clearly shown that not onl...

Facultative animal-bacteria symbioses, which are critical determinants of animal fitness, are largely assumed to be mutualistic. However, whether commensal bacteria benefit from the association has not been rigorously assessed. Using a simple and tractable gnotobiotic model- Drosophila mono-associated with one of its dominant commensals, Lactobacil...

The microbial environment influences animal physiology. However, the underlying molecular mechanisms of such functional interactions are largely undefined. Previously, we showed that during chronic undernutrition, strains of Lactobacillus plantarum, a major commensal partner of Drosophila, promote host juvenile growth and maturation partly through...

Nutrition is paramount in shaping all aspects of animal biology. In addition, the influence of the intestinal microbiota on physiology is now widely recognized. Given that diet also shapes the intestinal microbiota, this raises the question of how the nutritional environment and microbial assemblages together influence animal physiology. This resea...

Fig. S1. Foxp3 expression in the mesenteric lymph nodes and spleens of OVA‐treated mice.

Here, we compared the abilities of polysaccharides L900/2 and L900/3, which were previously isolated from Lactobacillus rhamnosus LOCK 0900, to modulate the immune response to bystander antigens in a mouse model of ovalbumin (OVA) sensitization. In vivo, both polysaccharides reduced the levels of OVA-specific IgE, IgE-dependent basophil degranulati...

The microbial environment influence animal physiology. However, the underlying molecular mechanisms of such functional interactions are largely undefined. Previously, we showed that upon chronic undernutrition, strains of Lactobacillus plantarum , a dominant commensal partner of Drosophila , promote host juvenile growth and maturation partly via en...

Germ-free animals have been used to define the vital role of commensal bacteria on the maturation of the host immune system. However, the role of bacterial residues in diet in this setting is poorly understood. Here we investigated the effect of bacterial contamination in sterile diet on the level of allergic sensitization in germ-free mice. Steril...

Composition of the feed mixture ST1. (DOCX)

Flow cytometry analyses of maturation of bone marrow-derived DC. Mouse bone marrow-derived DC (BM-DC) were prepared and stimulated as described in the manuscript. BM-DC were labelled with monoclonal antibodies for CD11c (FITC), MHC II (APC), CD40, CD80 or CD86 (PE) (eBioscience, USA). Appropriate isotype antibodies were used as controls to determin...

The Bifidobacteria show great diversity in the cell surface architecture which may influence the physicochemical properties of the bacterial cell and strain specific properties. The immunomodulatory role of bifidobacteria has been extensively studied, however studies on the immunoreactivity of their protein molecules are very limited. Here, we comp...

The Lactobacillus casei strain, LOCK 0919, is intended for the dietary management of food allergies and atopic dermatitis (LATOPIC® BIOMED). The use of a probiotic to modulate immune responses is an interesting strategy for solving imbalance problems of gut microflora that may lead to various disorders. However, the exact bacterial signaling mechan...

Increasing numbers of clinical trials and animal experiments have shown that probiotic bacteria are promising tools for allergy prevention. Here, we analyzed the immunomodulatory properties of three selected lactobacillus strains and the impact of their mixture on allergic sensitization to Bet v 1 using a gnotobiotic mouse model. We showed that Lac...

Microbiota and infant development Malnutrition in children is a persistent challenge that is not always remedied by improvements in nutrition. This is because a characteristic community of gut microbes seems to mediate some of the pathology. Human gut microbes can be transplanted effectively into germ-free mice to recapitulate their associated phen...

The genus Lactobacillus belongs to a large heterogeneous group of low G + C Gram-positive anaerobic bacteria, which are frequently used as probiotics. The health-beneficial effects, in particular the immunomodulation effect, of probiotics depend on the strain and dose used. Strain variations may be related to diversity of the cell surface architect...

Disturbances in the intestinal microbial community (i.e. dysbiosis) or presence of the microbes with deleterious effects on colonic mucosa has been linked to the pathogenesis of inflammatory bowel diseases. However the role of microbiota in induction and progression of ulcerative colitis (UC) has not yet been fully elucidated. Three lines of human...

Filamentous hemagglutinin (FHA) is an important adhesin of the whooping cough agent Bordetella pertussis and is contained in most acellular pertussis vaccines. Recently, FHA was proposed to exert an immunomodulatory activity through induction of tolerogenic IL-10 secretion from dendritic cells. We have re-evaluated the cytokine-inducing activity of...

Background: Reduced microbial diversity has been associated with inflammatory bowel disease (IBD) and probiotic bacteria have been proposed for its prevention and/or treatment. Nevertheless, comparative studies of strains of the same subspecies for specific health benefits are scarce. Here we compared two Bifidobacterium longum ssp. longum strains...

A decrease in the abundance and biodiversity of intestinal bacteria within the Firmicutes phylum has been associated with inflammatory bowel disease (IBD). In particular, the anti-inflammatory bacterium Faecalibacterium prausnitzii, member of the Firmicutes phylum and one of the most abundant species in healthy human colon, is underrepresented in t...

Background: Our previous studies on intranasal tolerance induction demonstrated reduction of allergic responses with different allergen constructs. The underlying mechanisms varied depending on their conformation or size. Objective: The aim of the present study was to compare the uptake of two structurally different allergen molecules within the...