Antiviral activity of bacterial TIR domains via immune signalling molecules

The Toll/interleukin-1 receptor (TIR) domain is a canonical component of animal and plant immune systems^1,2. In plants, intracellular pathogen sensing by immune receptors triggers their TIR domains to generate a molecule that is a variant of cyclic ADP-ribose^3,4. This molecule is hypothesized to mediate plant cell death through a pathway that has yet to be resolved⁵. TIR domains have also been shown to be involved in a bacterial anti-phage defence system called Thoeris⁶, but the mechanism of Thoeris defence remained unknown. Here we show that phage infection triggers Thoeris TIR-domain proteins to produce an isomer of cyclic ADP-ribose. This molecular signal activates a second protein, ThsA, which then depletes the cell of the essential molecule nicotinamide adenine dinucleotide (NAD) and leads to abortive infection and cell death. We also show that, similar to eukaryotic innate immune systems, bacterial TIR-domain proteins determine the immunological specificity to the invading pathogen. Our results describe an antiviral signalling pathway in bacteria, and suggest that the generation of intracellular signalling molecules is an ancient immunological function of TIR domains that is conserved in both plant and bacterial immunity.

Microbiota in Rosacea

Rosacea is a complex facial skin condition associated with abnormal inflammation and vascular dysfunction. Next to the known trigger factors, the role of microbiota in the development and aggravation of rosacea continues to raise interest. Demodex folliculorum mites, Helicobacter pylori, Staphylococcus epidermidis, Chlamydia pneumoniae, and the Demodex-associated bacterium, Bacillus oleronius are microbes that have been linked with rosacea. However, the results of studies which assessed their involvement in the disease have been inconsistent and inconclusive. Microbiological research in many different disciplines exploded in recent years as methods to analyze complex microbial communities at the taxonomic and phylogenetic levels became available. Here, we provide an update on the microorganisms implicated in rosacea and review the potential pathogenic role of microbes in the development of rosacea.

Effects of three host-associated Bacillus species on mucosal immunity and gut health of Nile tilapia, Oreochromis niloticus and its resistance against Aeromonas hydrophila infection

Skin and intestinal mucosa lymphoid tissues are known to be the fish's first line of defence since they serve as the first point of contact for pathogens. Only few studies have investigated the influence of host-associated Bacillus on mucosal immunity. In this study, the effects of three host-associated Bacillus species on mucosal immunity, intestinal morphology, intestinal digestive enzymes activity, intestinal microbiome and resistance of Nile tilapia against Aeromonas hydrophila infection was evaluated. The fish were divided into five treatment groups and fed with diets containing no bacteria denoted as Control, Bacillus velezensis TPS3N denoted as group V, Bacillus subtilis TPS4 denoted as group S, Bacillus amyloliquefaciens TPS17 denoted as group A and a 5^th group containing the three Bacillus species at a ratio 1:1:1 denoted as group CB. At the end of the feeding trial, significant enhancement of both skin mucus and intestinal immune titres were recorded in terms of nitric oxide (NO) (except in the mucus of V and S groups), immunoglobulin M (IgM) (except in the intestine of group V), lysozyme (LZM), and alkaline phosphatase (AKP) in all fish fed the Bacillus supplemented groups relative to the untreated group. Intestinal antioxidant enzymes (catalase (CAT) (except in the intestine of group S) and superoxide dismutase (SOD)) capacity of Nile tilapia were higher in the Bacillus groups. Intestinal lipase activity was elevated in the Bacillus supplemented groups. The intestinal morphological parameters (villus height, villus width, goblet cells count (except in group S and A), and intestinal muscle thickness) were significantly enhanced in the Bacillus supplemented groups relative to the Control group. Dietary probiotic supplementation also influenced the intestinal microflora composition of Nile tilapia. Proteobacteria recorded the highest abundance followed by Firmicutes, Fusobacteria, and Bacteroidetes at the phylum level in this study. At the genus level, the abundance of pathogenic bacteria viz Staphylococcus and Aeromonas were reduced in the Bacillus supplemented groups in comparison to the Control group. A challenge test with A. hydrophila resulted in lower mortalities (%) in the Bacillus treated groups thus 86.67%, 50.00%, 43.33%, 63.33%, and 30.00% for Nile tilapia fed Control, V, S, A, and CB diets respectively. In conclusion, the inclusion of B. velezensis TPS3N, B. subtilis TPS4, and B. amyloliquefaciens TPS17 in the diet of Nile tilapia singularly or in combination, could enhance the mucosal immunity, intestinal health, and resistance of Nile tilapia against A. hydrophila infection.

Bacillus velezensis CC09: A Potential 'Vaccine' for Controlling Wheat Diseases

Biocontrol bacteria that can act like a "vaccine", stimulating plant resistance to pathogenic diseases, are still not fully elucidated. In this study, an endophytic bacterium, Bacillus velezensis CC09, labeled with green fluorescent protein, was tested for its colonization, migration, and expression of genes encoding iturin A synthetase within wheat tissues and organs as well as for protective effects against wheat take-all and spot blotch diseases. The results showed that strain CC09 not only formed biofilm on the root surface but was also widely distributed in almost every tissue, including the epidermis, cortex, and xylem vessels, and even migrated to stems and leaves, resulting in 66.67% disease-control efficacy (DCE) of take-all and 21.64% DCE of spot blotch. Moreover, the gene cluster encoding iturin A synthase under the control of the p_itu promoter is expressed in B. velezensis CC09 in wheat tissues, which indicates that iturin A might contribute to the in-vivo antifungal activity and leads to the disease control. All these data suggested that strain CC09 can act like a 'vaccine' in the control of wheat diseases, with a single treatment inoculated on roots through multiple mechanisms.

Activation of Neutrophils via IP3 Pathway Following Exposure to Demodex-Associated Bacterial Proteins

Rosacea is a chronic inflammatory condition that predominantly affects the skin of the face. Sera from rosacea patients display elevated reactivity to proteins from a bacterium (Bacillus oleronius) originally isolated from a Demodex mite from a rosacea patient suggesting a possible role for bacteria in the induction and persistence of this condition. This work investigated the ability of B. oleronius proteins to activate neutrophils and demonstrated activation via the IP3 pathway. Activated neutrophils displayed increased levels of IP1 production, F-actin formation, chemotaxis, and production of the pro-inflammatory cytokines IL-1β and IL-6 following stimulation by pure and crude B. oleronius protein preparations (2 μg/ml), respectively. In addition, neutrophils exposed to pure and crude B. oleronius proteins (2 μg/ml) demonstrated increased release of internally stored calcium (Ca(2+)), a hallmark of the IP3 pathway of neutrophil activation. Neutrophils play a significant role in the inflammation associated with rosacea, and this work demonstrates how B. oleronius proteins can induce neutrophil recruitment and activation.

Effect of mixed-Bacillus spp isolated from pustulose ark Anadara tuberculosa on growth, survival, viral prevalence and immune-related gene expression in shrimp Litopenaeus vannamei

The widespread overuse of antibiotics in aquaculture has led to the emergence of antibiotic-resistance shrimp pathogens, the negative impact on shrimp gut microbiota, and the presence of antimicrobial residues in aquaculture products, with negative consequences on human health. Alternatively, probiotics have positive effects on immunological responses and productive performance of aquatic animals. In this study, three probiotic bacteria, (Bacillus licheniformis MAt32, B. subtilis MAt43 and B. subtilis subsp. subtilis GAtB1), isolated from the Anadara tuberculosa were included in diets for juvenile shrimp, Litopenaeus vannamei, to evaluate their effects on growth, survival, disease prevalence, and immune-related gene expression. Shrimp naturally infected with WSSV and IHHNV were fed with the basal diet (control, T1) and diets supplemented with four levels of bacilli probiotic mix (1:1:1) at final concentration of (T2) 1 × 10⁶, (T3) 2 × 10⁶, (T4) 4 × 10⁶, and (T5) 6 × 10⁶ CFU g^-1 of feed. The specific growth rate of shrimp was significantly higher in T2 than in T1 (control) treatment, and the final growth as well as the survival were similar among treated groups. The prevalence of WSSV and IHHNV infected shrimp was reduced in T2 and T4 treatments, respectively, compared with control. The mRNA expression of proPO gene was higher in treatment T4 than control. The LvToll1 gene was significantly up-regulated in treatments T4 and T5 compared to control. The SOD gene was up-regulated in treatment T5 compared to control. In contrast, the mRNA expression of the Hsp70 gene was down-regulated in treatments T4 and T5 respect to control, and the TGase gene remained unaffected by the level of bacillus probiotic mix. As conclusion, the bacilli probiotic mix (Bacillus spp.) enhanced immune-related gene expression in WSSV and IHHNV naturally infected shrimp. This is the first report of probiotic potential of bacteria isolated from A. tuberculosa on the immune response and viral prevalence in shrimp Litopenaeus vannamei.

Dietary supplementation of probiotic Bacillus PC465 isolated from the gut of Fenneropenaeus chinensis improves the health status and resistance of Litopenaeus vannamei against white spot syndrome virus

This study conducted a 30-day feeding trial and a subsequent 20-day anti-virus infection trial to determine the effects of probiotic Bacillus PC465 on the growth, health status, and disease resistance of Litopenaeus vannamei. Shrimp samples were fed with three practical diets prepared from shrimp feed containing varying probiotic doses [0 (control), 10(7), and 10(9) CFU g(-1)]. Probiotic supplementation significantly increased the weight gain and survival of L. vannamei (p < 0.05). The effect of 10(9) CFU g(-1) on the growth rate was higher than that of 10(7) CFU g(-1). Compared with those in the control group, the activities of digestive enzymes, such as amylase, protease, and lipase, in the shrimp mid-gut significantly increased in the probiotic-fed groups on days 15 and 30, except lipase on day 30. The influence of 10(9) CFU g(-1) on enzyme activities was also greater than that of 10(7) CFU g(-1). Scanning electron microscopy revealed folds and large ravines across the interior surface of the mid-gut, and the number of these folds and ravines increased significantly after the probiotic was administered. The probiotic treatment significantly (p < 0.05) enhanced the transcription of penaeidin 3a (Pen-3a), peroxinectin, C-type lectin 3 (Lec-3), and thioredoxin (Trx) in the hemocytes of L. vannamei. Likewise, probiotic treatment increased the transcription of hemocyanin in the hepatopancreas of L. vannamei. The probiotic treatment also significantly increased the transcription of prophenoloxidase (proPO) but decreased the transcription of crustin in hemocytes. By contrast, the same treatment failed to increase the transcription of Ras-related protein (Rab-6) in hemocytes. The number of species and biomass of Bacillus in the mid-gut were higher in the probiotic-fed group than in the control group. The total biomass of microbes was higher in the shrimp fed with 10(7) CFU g(-1) than in the shrimp fed with 10(9) CFU g(-1) and the control group on days 15 and 30 post-feeding. In two white spot syndrome virus (WSSV) infections, the weight gain, survival, and WSSV copies within the gills of the probiotic-treated shrimp significantly differed (p < 0.05) from those of the control group. Relatively efficient protection was associated with probiotic feeding. Results suggested that Bacillus PC465 feeding improves the growth performance, survival, digestion, and nutrient absorption of L. vannamei. Probiotic treatment also enhances the microbial structures in the gut, promotes the immune status of shrimp, and provides protection against viral infection. The supplementation with 10(9) CFU g(-1) can also improve the growth and survival of L. vannamei.

Isolation of potential probiotic Bacillus spp. and assessment of their subcellular components to induce immune responses in Labeo rohita against Aeromonas hydrophila

Bacillus species isolated from the gut of healthy Labeo rohita (Hamilton) were screened for antibacterial activity against selected fish pathogens. Among the isolates, KADR5 and KADR6 showed antibacterial activity, tolerated low pH and high bile concentrations and were susceptibility to various antibiotics. Based on morphological and biochemical tests and 16S rRNA gene analysis the probiotic strains KADR5 and KADR6 were identified as Bacillus licheniformis and Bacillus pumilus, respectively. The immune stimulatory effect of subcellular components of probiotic Bacillus licheniformis KADR5 and Bacillus pumilus KADR6 in L. rohita against Aeromonas hydrophila infection was studied. Fish were immunized intraperitoneally in case of subcellular components [cell wall proteins (CWPs), extracellular proteins (ECPs), whole cell proteins (WCPs)] and orally in case of live cells (10(8) CFU/g of feed). After 14th day of administration, fishes from each group were challenged intraperitoneally with 0.1 ml of A. hydrophila cell suspension in PBS (10(5) cells ml(-1)). Groups immunized with subcellular components and live cells had significantly lower mortalities of 20-40% and 23-33%, respectively in comparison to control (80% mortality). The non specific immune factors in the cellular components and viable cells of the probiotics increased the expression of lysozyme and respiratory burst. Use of WCPs and CWPs resulted in better protection against A. hydrophila in L. rohita. Our results clearly reflect the potential of cellular components of the probiotics Bacillus species for the protection of fish against A. hydrophila infection by enhancing the immune response.

[INTESTINE MICROBIOTA IN CHILDREN WITH OBESITY AND ALLERGIC DISEASES]

AIM

Study intestine microflora in children with obesity and evaluate its association with allergic diseases. MATERIALS AND METHODS. 66 children with various body weight aged 3 to 17 years were included into the study. Intestine microflora study in children was carried out according to the order of the Ministry of Health of Russian Federation No. 231 of 09.06.2003 "Regarding approval of sectoral standard "Patient management protocol. Intestine dysbacteriosis" (SST 91500.11.0004-2003).

RESULTS

In healthy children depending on body weight an increase of the number of Firmicutes type microorganisms and a decrease of the number of microbes, belonging to Bacteroidetes type, was detected. The presence of allergic pathology was accompanied by a decrease of the number of Bacteroidetes and the presence of Bacillus and Staphylococcus aureus regardless of the body weight. At the same time, in all the children an increase of the content of Clostridium with the increase of body mass was noted. CONCLUSION. The data obtained have revealed an association of changes in intestine microbiota with the development of obesity and allergopathology.

Characterizing Metal-Dependent Nucleases of CRISPR-Cas Prokaryotic Adaptive Immunity Systems

CRISPRs (clustered regularly interspaced short palindromic repeats), together with the nearby CRISPR-associated (cas) operon, constitute a prokaryotic RNA-based adaptive immune system against exogenous genetic elements. Here, we describe nuclease assays that are useful for characterizing the substrate-specific function of CRISPR-associated protein Cas2. We also provide methods for characterizing the stoichiometry and affinity between Cas2 and divalent metal ions using isothermal titration calorimetry (ITC).

Enhancement of the immune response and protection against Vibrio parahaemolyticus by indigenous probiotic Bacillus strains in mud crab (Scylla paramamosain)

In a previous study, bacterial communities of the intestine in three populations of crabs (wild crabs, pond-raised healthy crabs and diseased crabs) were probed by culture-independent methods. In this study, we examined the intestinal communities of the crabs by bacterial cultivation with a variety of media. A total of 135 bacterial strains were isolated from three populations of mud crabs. The strains were screened for antagonistic activity against Vibrio parahaemolyticus using an agar spot assay. Antagonistic strains were then identified by 16S rRNA gene sequence analysis. Three strains (Bacillus subtilis DCU, Bacillus pumilus BP, Bacillus cereus HL7) with the strongest antagonistic activity were further evaluated for their probiotic characteristics. The results showed that two (BP and DCU) of them were able to survive low pH and high bile concentrations, showed good adherence characteristics and a broad spectrum of antibiotic resistance. The probiotic effects were then tested by feeding juvenile mud crabs (Scylla paramamosain) with foods supplemented with 10(5) CFU/g of BP or DCU for 30 days before being subjected to an immersion challenge with V. parahaemolyticus for 48 h. The treated crabs showed significantly higher expression levels of immune related genes (CAT, proPO and SOD) and activities of respiratory burst than that in controlled groups. Crabs treated with BP and DCU supplemented diets exhibited survival rates of 76.67% and 78.33%, respectively, whereas survival rate was 54.88% in crabs not treated with the probiotics. The data showed that indigenous mud-associated microbiota, such as DCU and BP, have potential application in controlling pathogenic Vibriosis in mud crab aquaculture.

Calnexin functions in antibacterial immunity of Marsupenaeus japonicus

Calnexin (Cnx) is an endoplasmic reticulum membrane-bound lectin chaperone that comprises a dedicated maturation system with another lectin chaperone calreticulin (Crt). This maturation system is known as the Cnx/Crt cycle. The main functions of Cnx are Ca(2+) storage, glycoprotein folding, and quality control of synthesis. Recent studies have shown that Cnx is important in phagocytosis and in optimizing dendritic cell immunity. However, the functions of Cnx in invertebrate innate immunity remain unclear. In this research, we characterized Cnx in the kuruma shrimp Marsupenaeus japonicus (designated as MjCnx) and detected its function in shrimp immunity. The expression of MjCnx was upregulated in several tissues challenged with Vibrio anguillarum. Recombinant MjCnx could bind to bacteria by binding polysaccharides. MjCnx protein existed in the cytoplasm and on the membrane of hemocytes and was upregulated by bacterial challenge. The recombinant MjCnx enhanced the clearance of V. anguillarum in vivo, and the clearance effects were impaired after silencing MjCnx with RNA interference assay. Recombinant MjCnx promoted phagocytosis efficiency of hemocytes. These results suggest that MjCnx functions as one of the pattern recognition receptors and has crucial functions in shrimp antibacterial immunity.

Combined effects of dietary fructooligosaccharide and Bacillus licheniformis on innate immunity, antioxidant capability and disease resistance of triangular bream (Megalobrama terminalis)

This study was conducted to investigate the effects of fructooligosaccharide (FOS) and Bacillus licheniformis (B. licheniformis) and their interaction on innate immunity, antioxidant capability and disease resistance of triangular bream Megalobrama terminalis (average initial weight 30.5 ± 0.5 g). Nine experimental diets were formulated to contain three FOS levels (0, 0.3% and 0.6%) and three B. licheniformis levels (0, 1 × 10(7), 5 × 10(7) CFU g(-1)) according to a 3 × 3 factorial design. At the end of the 8-week feeding trial, fish were challenged by Aeromonas hydrophila (A. hydrophila) and survival rate was recorded for the next 7 days. The results showed that leucocyte counts, alternative complement activity as well as total serum protein and globulin contents all increased significantly (P < 0.05) as dietary B. licheniformis levels increased from 0 to 1 × 10(7) CFU g(-1), while little difference (P > 0.05) was observed in these parameters in terms of dietary FOS levels. Both plasma alkaline phosphatase and phenoloxidase activities were significantly (P < 0.05) affected only by dietary FOS levels with the highest values observed in fish fed 0.6 and 0.3% FOS, respectively. Both immunoglobulin M content and liver superoxide dismutase (SOD) activity were significantly affected (P > 0.05) by both FOS and B. licheniformis. Liver catalase, glutathione peroxidase as well as plasma SOD activities of fish fed 1 × 10(7) CFU g(-1)B. licheniformis were all significantly (P < 0.05) higher than that of the other groups, whereas the opposite was true for malondialdehyde content. After A. hydrophila challenge, survival rate was not affected (P > 0.05) by either FOS levels or B. licheniformis contents, whereas a significant (P < 0.05) interaction between these two substances was observed with the highest value observed in fish fed 0.3% FOS and 1 × 10(7) CFU g(-1)B. licheniformis. The results of this study indicated that dietary FOS and B. licheniformis could significantly enhance the innate immunity and antioxidant capability of triangular bream, as well as improve its disease resistance. The best combination of these two prebiotics and/or probiotics was 0.3% FOS and 1 × 10(7) CFU g(-1)B. licheniformis.

Environmental biodiversity, human microbiota, and allergy are interrelated

Rapidly declining biodiversity may be a contributing factor to another global megatrend--the rapidly increasing prevalence of allergies and other chronic inflammatory diseases among urban populations worldwide. According to the "biodiversity hypothesis," reduced contact of people with natural environmental features and biodiversity may adversely affect the human commensal microbiota and its immunomodulatory capacity. Analyzing atopic sensitization (i.e., allergic disposition) in a random sample of adolescents living in a heterogeneous region of 100 × 150 km, we show that environmental biodiversity in the surroundings of the study subjects' homes influenced the composition of the bacterial classes on their skin. Compared with healthy individuals, atopic individuals had lower environmental biodiversity in the surroundings of their homes and significantly lower generic diversity of gammaproteobacteria on their skin. The functional role of the gram-negative gammaproteobacteria is supported by in vitro measurements of expression of IL-10, a key anti-inflammatory cytokine in immunologic tolerance, in peripheral blood mononuclear cells. In healthy, but not in atopic, individuals, IL-10 expression was positively correlated with the abundance of the gammaproteobacterial genus Acinetobacter on the skin. These results raise fundamental questions about the consequences of biodiversity loss for both allergic conditions and public health in general.

Bombyx mori transcription factors: genome-wide identification, expression profiles and response to pathogens by microarray analysis

Transcription factors are present in all living organisms, and play vital roles in a wide range of biological processes. Studies of transcription factors will help reveal the complex regulation mechanism of organisms. So far, hundreds of domains have been identified that show transcription factor activity. Here, 281 reported transcription factor domains were used as seeds to search the transcription factors in genomes of Bombyx mori L. (Lepidoptera: Bombycidae) and four other model insects. Overall, 666 transcription factors including 36 basal factors and 630 other factors were identified in B. mori genome, which accounted for 4.56% of its genome. The silkworm transcription factors' expression profiles were investigated in relation to multiple tissues, developmental stages, sexual dimorphism, and responses to oral infection by pathogens and direct bacterial injection. These all provided rich clues for revealing the transcriptional regulation mechanism of silkworm organ differentiation, growth and development, sexual dimorphism, and response to pathogen infection.

The bacterial lipopeptide surfactin targets the lipid fraction of the plant plasma membrane to trigger immune-related defence responses

The lipopeptide surfactin secreted by plant-beneficial bacilli has crucial biological functions among which the ability to stimulate immune-related responses in host tissues. This phenomenon is important for biological control of plant diseases but its molecular basis is still poorly understood. In this work, we used various approaches to study the mechanism governing the perception of this biosurfactant at the plant cell surface. Combining data on oxidative burst induction in tobacco cells, structure/activity relationship, competitive inhibition, insertion kinetics within plant membranes and thermodynamic determination of binding parameters on model membranes globally indicates that surfactin perception relies on a lipid-driven process at the plasma membrane level. Such a sensor role of the lipid bilayer is quite uncommon considering that plant basal immunity is usually triggered upon recognition of microbial molecular patterns by high-affinity proteic receptors.

Properties of bacteria that trigger hemocytopenia in the Atlantic blue crab, Callinectes sapidus

In the blue crab Callinectes sapidus, injection with the bacterial pathogen Vibrio campbellii causes a decrease in oxygen consumption. Histological and physiological evidence suggests that the physical obstruction of hemolymph flow through the gill vasculature, caused by aggregations of bacteria and hemocytes, underlies the decrease in aerobic function associated with bacterial infection. We sought to elucidate the bacterial properties sufficient to induce a decrease in circulating hemocytes (hemocytopenia) as an indicator for the initiation of hemocyte aggregation and subsequent impairment of respiration. Lipopolysaccharide (LPS), the primary component of the gram-negative bacterial cell wall, is known to interact with crustacean hemocytes. Purified LPS was covalently bound to the surfaces of polystyrene beads resembling bacteria in size. Injection of these "LPS beads" caused a decrease in circulating hemocytes comparable to that seen with V. campbellii injection, while beads alone failed to do so. These data suggest that in general, gram-negative bacteria could stimulate hemocytopenia. To test this hypothesis, crabs were injected with different bacteria--seven gram-negative and one gram-positive species--and their effects on circulating hemocytes were assessed. With one exception, all gram-negative strains caused decreases in circulating hemocytes, suggesting an important role for LPS in the induction of this response. However, LPS is not necessary to provoke the immune response given that Bacillus coral, a gram-positive species that lacks LPS, caused a decrease in circulating hemocytes. These results suggest that a wide range of bacteria could impair metabolism in C. sapidus.

Immunostimulatory activities of Bacillus simplex DR-834 to carp (Cyprinus carpio)

A bacterial strain, designated DR-834 and producing immunostimulatory activities to carp (Cyprinus carpio), was isolated from Qinghai-Tibetan Plateau permafrost soil. Cultural characteristic studies suggested that this strain belongs to the genus Bacillus. The nucleotide sequence of the 16S rRNA gene of strain DR-834 exhibited close similarity (99%) with the 16S rRNA gene of Bacillus simplex. Two compounds showing potent activity were isolated from secondary metabolites of the strain through bioassay-guided isolation techniques and identified by spectral data (infrared, nuclear magnetic resonance and mass spectrometry) as: (1) 4-trans-hydroxy-l-proline and (2) cyclo-(l-Pro-Gly)(2). They were found to be significantly increased the selected innate immune function parameters, serum SOD activity, serum lysozyme activity, serum bactericidal activity, superoxide anion production and phagocytic activity by isolated blood leucocytes. The effects of two compounds on immune-related genes expression were further investigated. The outcomes of real-time quantitative polymerase chain reaction (RQ-PCR) proved that the transcribing level of interleukin 1beta (IL-1beta) and inducible nitric oxide synthase (iNOS) mRNA in the blood have been augmented by 4-trans-hydroxy-l-proline and cyclo-(l-Pro-Gly)(2). Compounds 1 and 2 administration the challenge with live Aeromonas hydrophila decreased the percentage mortality in the experimental groups with the consequence increase in relative percent survival (RPS) values. Compound 2 produced the highest protection with the RPS values of 87.50, 77.78, 55.56 and 55.56 after 1, 2, 3 and 4 weeks, respectively. The study indicates that the isolated compounds could be positively influence the immune response and protect the heath status of carp against A. hydrophila infection.

GanedenBC30 cell wall and metabolites: anti-inflammatory and immune modulating effects in vitro

BACKGROUND

This study was performed to evaluate anti-inflammatory and immune modulating properties of the probiotic, spore-forming bacterial strain: Bacillus coagulans: GBI-30, (PTA-6086, GanedenBC30TM). In addition, cell wall and metabolite fractions were assayed separately to address whether biological effects were due to cell wall components only, or whether secreted compounds from live bacteria had additional biological properties. The spores were heat-activated, and bacterial cultures were grown. The culture supernatant was harvested as a source of metabolites (MTB), and the bacteria were used to isolate cell wall fragments (CW). Both of these fractions were compared in a series of in vitro assays.

RESULTS

Both MTB and CW inhibited spontaneous and oxidative stress-induced ROS formation in human PMN cells and increased the phagocytic activity of PMN cells in response to bacteria-like carboxylated fluorospheres. Both fractions supported random PMN and f-MLP-directed PMN cell migration, indicating a support of immune surveillance and antibacterial defense mechanisms. In contrast, low doses of both fractions inhibited PMN cell migration towards the inflammatory mediators IL-8 and LTB4. The anti-inflammatory activity was strongest for CW, where the PMN migration towards IL-8 was inhibited down to dilutions of 1010.Both MTB and CW induced the expression of the CD69 activation marker on human CD3- CD56+ NK cells, and enhanced the expression of CD107a when exposed to K562 tumor cells in vitro.The fractions directly modulated cytokine production, inducing production of the Th2 cytokines IL-4, IL-6, and IL-10, and inhibiting production of IL-2.Both fractions further modulated mitogen-induced cytokine production in the following manner: Both fractions enhanced the PHA-induced production of IL-6 and reduced the PHA-induced production of TNF-alpha. Both fractions enhanced the PWM-induced production of TNF-alpha and IFN-gamma. In addition, MTB also enhanced both the PHA- and the PWM-induced expression of IL-10.

CONCLUSION

The data suggest that consumption of GanedenBC30TM may introduce both cell wall components and metabolites that modulate inflammatory processes in the gut. Both the cell wall and the supernatant possess strong immune modulating properties in vitro. The anti-inflammatory effects, combined with direct induction of IL-10, are of interest with respect to possible treatment of inflammatory bowel diseases as well as in support of a healthy immune system.

Molecular mechanism of plant growth promotion and induced systemic resistance to tobacco mosaic virus by Bacillus spp

Bacillus spp., as a type of plant growth-promoting rhizobacteria (PGPR), were studied with regards promoting plant growth and inducing plant systemic resistance. The results of greenhouse experiments with tobacco plants demonstrated that treatment with the Bacillus spp. significantly enhanced the plant height and fresh weight, while clearly lowering the disease severity rating of the tobacco mosaic virus (TMV) at 28 days post-inoculation (dpi). The TMV accumulation in the young non-inoculated leaves was remarkably lower for all the plants treated with the Bacillus spp. An RTPCR analysis of the signaling regulatory genes Coi1 and NPR1, and defense genes PR-1a and PR-1b, in the tobacco treated with the Bacillus spp. revealed an association with enhancing the systemic resistance of tobacco to TMV. A further analysis of two expansin genes that regulate plant cell growth, NtEXP2 and NtEXP6, also verified a concomitant growth promotion in the roots and leaves of the tobacco responding to Bacillus spp.

[Effect of the drug-resistant attenuated Bacillus proteus on CD80 and CD86 protein expression in peripheral blood dendritic cells of hepatitis B patients]

OBJECTIVE

To explore the effect of the drug-resistant attenuated Bacillus proteus on the protein expression of CD80 and CD86 in peripheral blood dendritic cells (DCs) of hepatitis B patients.

METHOD

Peripheral blood monocytes were isolated from HBV-infected patients and the DCs were separated and induced to differentiate in vitro. The expression of CD80 and CD86 proteins on cultured DCs were examined using flow cytometry.

RESULTS

The expression rate of CD80 and CD86 of chronic hepatitis B patients increased significantly (P=0.000), while the positive expression rate of CD80 and CD86 showed no obvious variation in healthy individuals (P=0.185 and P=0.118, respectively).

CONCLUSIONS

Bacillus proteus can significantly increase CD80- and CD86-positive cell percentage in peripheral blood DCs of HBV-infected patients, but has no such an effect in healthy individuals.

[Composition and immunochemical characteristics of exopolysaccharides from the rhizobacterium Paenibacillus polymyxa 1465]

Exopolysaccharides (EPS) synthesized by Paenibacillus polymyxa 1465 in the course of batch cultivation were proven to contain neutral and acidic fractions. EPS are heterogeneous polysaccharides, represented by a complex of macromolecules with molecular mass of 7 x 10(4) to 2 x 10(6) Da. The acidic component was shown to be predominant in EPS preparations isolated from bacteria cultivated on glucose, which corresponds to a higher viscosity of EPS water solutions. The exoglycans were shown to contain glucose, mannose, galactose, and uronic acids. Polyclonal rabbit antibodies against the isolated P. polymyxa 1465 EPS preparations were used in a comparative immunodiffusion analysis of a number of P. polymyxa strains.

Mite-related bacterial antigens stimulate inflammatory cells in rosacea

BACKGROUND

Patients with papulopustular rosacea have a higher density of Demodex folliculorum mites on their faces than normal subjects but the role, if any, of their mites in initiating inflammation is disputed. Selective antibiotics are effective in reducing the inflammatory changes of papulopustular rosacea, but their mode of action is unknown.

OBJECTIVES

To investigate whether a D. folliculorum-related bacterium was capable of expressing antigens that could stimulate an inflammatory immune response in patients with rosacea.

METHODS

A bacterium (Bacillus oleronius) was isolated from a D. folliculorum mite extracted from the face of a patient with papulopustular rosacea, and was investigated further.

RESULTS

This bacterium produced antigens capable of stimulating peripheral blood mononuclear cells proliferation in 16 of 22 (73%) patients with rosacea but only five of 17 (29%) control subjects (P = 0.0105). This antigenic preparation was fractionated into 70 subfractions and the proteins in each fraction were visualized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Western blot analysis revealed the presence of two antigenic proteins of size 62 and 83 kDa in fractions when probing with sera from patients with rosacea. No immunoreactivity to these proteins was recorded when probing with sera from control patients. Two-dimensional electrophoretic separation was used to isolate these proteins and matrix-assisted laser desorption/ionization time-of-flight analysis was employed to identify the relevant peptides. The 62-kDa immunoreactive protein shared amino acid sequence homology with an enzyme involved in carbohydrate metabolism and signal transduction while the 83-kDa protein was similar to bacterial heat shock proteins.

CONCLUSIONS

Antigenic proteins related to a bacterium (B. oleronius), isolated from a D. folliculorum mite, have the potential to stimulate an inflammatory response in patients with papulopustular rosacea.

Stabilization of Bacillus licheniformis alpha-amylase by specific antibody which recognizes the N-terminal fragment of the enzyme

Bacillus licheniformis alpha-amylase (BLA) is an industrially important extracellular enzyme with a number of applications. In the present work, an investigation was carried out on the tryptolytic digestion of BLA which produced two fragments, TF18K and TF38K, and no further fragments could be seen after 6h incubation of BLA with trypsin. The fragments were isolated by preparative gel electrophoresis and reverse phase HPLC. The N-terminal sequencing of fragments showed that trypsin attacks on Arg(127)-Val(128) peptide bond in BLA. Intrinsic and acrylamide quenching fluorescence experiments and Far-UV circular dichroism studies showed that substantial changes in the secondary and tertiary structures of the TF18K and TF38K have occurred. Subsequently, polyclonal antibody was raised against TF18K. After purification of the antibody by protein A Sepharose, thermal stability of BLA in the presence of this antibody was determined. Results showed that the presence of antiTF18K leads to significant stabilization of BLA. For example, after 30 min incubation at 90 degrees C, residual activity of the enzyme in the presence of antibody (40 microg/ml) was determined as 40% while the enzyme showed no activity in the absence of antibody after incubating in the same condition. In addition, it has been proved that calcium enhances the thermal stability of BLA and a synergistic stabilization of BLA has been seen with antiTF18K and calcium, simultaneously.

Rapid diagnostic thin section electron microscopy of bacterial endospores

Emerging infectious diseases such as SARS and the bioterror attacks with anthrax spores that occurred after September 11th, 2001 have highlighted the need to be better prepared for the detection and management of infectious pathogens that threaten public health. Negative staining electron microscopy is one method used to screen environmental and clinical samples for relevant infectious pathogens. Unfortunately, bacterial endospores, like those of Bacillus anthracis, are difficult to identify using this method because of their density that prevents imaging of structural details. Thin section electron microscopy would be an alternative method but this usually requires a few days for preparation and diagnosis. In the present paper we describe the development of a rapid thin section protocol, using mainly Bacillus subtilis spores as a model, which allows an unequivocal diagnosis of endospores within 2 h. The protocol involves chemical fixation assisted by heat or microwaves, rapid dehydration, embedding in the low-viscosity resin LR White and chemically enhanced polymerization. Structural preservation of spores is comparable to preservation after standard Epon embedding. Immunolabeling experiments using B. atrophaeus spores and a specific antibody suggest that the protocol preserves significant antigenicity for on-section immunocytochemistry and therefore offers the possibility for the strain typing of spores using specific antibodies. Further experiments with vegetative bacteria, viruses and cell cultures indicate that the rapid thin section protocol not only preserves spores but also other biological structures. Because of its universality and speed the described protocol complements negative staining electron microscopy as a front line method for the morphology-based diagnosis of pathogens in environmental and clinical samples.

Effects of Salmonella enterica serovar Typhimurium, or serovar Choleraesuis, Lactobacillus reuteri and Bacillus licheniformis on chemokine and cytokine expression in the swine jejunal epithelial cell line, IPEC-J2

Direct-fed microbials, including Lactobacillus and Bacillus spp., are potential replacements for low dose in-feed antibiotics for swine and other livestock. To understand the function of these microbes in the gut, the current study used pig jejunal epithelial cells (IPEC-J2) to evaluate how Lactobacillus reuteri (LR) and Bacillus licheniformis (BL) differed from Salmonella enterica serovars Typhimurium (ST) or Choleraesuis (SC) in their ability to regulate, stimulate, or modify the proinflammatory mediators, interleukin 8 (IL8), CC chemokine 20 (CCL20), and tumor necrosis factor-alpha (TNFalpha). To optimize the positive control to drive IL8 secretion by IPEC-J2 cells, cells were treated apically with various concentrations of ST (versus control (CTL)) for 1h, followed by a wash. Media containing gentamicin was added and collected at 6h post-treatment. Compared to CTL, 10(8) ST produced maximal IL8 secretion in both the apical and basolateral directions, with significant basolateral polarization (P<0.0001). We next evaluated the time course of IL8 secretion, and IL8, CCL20, and TNFalpha mRNA expression by IPEC-J2 cells treated apically with 10(8) ST, SC, LR, and BL versus CTL. Media and RNA were collected at 1.5, 3.0, and 6.0 h post treatment. Only ST stimulated an increase in IL8 secretion at any time point, with increases in IL8 mRNA at both 3 and 6h (P<0.05). However, BL increased IL8 mRNA at 1.5h (P<0.0001). Neither LR nor SC affected IL8 mRNA expression. CCL20 mRNA was strongly upregulated by ST (P<0.05) and BL (1.5 and 3.0 h; P<0.05), but not LR or SC. Only ST increased TNFalpha mRNA relative to CTL (P<0.05). Two experiments were conducted to determine if pre-exposure of IPEC-J2 cells to LR or BL modified ST induced IL8 secretion. Confluent cells were treated apically overnight with various levels of LR or BL (in separate experiments) followed by ST challenge. Media were collected at 4 (LR experiment) or 5h (BL experiment) post ST. In the LR study, IL8 secretion was increased by ST as compared to CTL (P<0.0001), reduced by LR (P<0.05), and LR+ST co-treatments failed to alter ST stimulated secretion. In the BL experiment, secretion of IL8 was increased by ST (P<0.0001), but blunted basolaterally in BL+ST co-treated wells. The data demonstrate that IPEC-J2 cells increase IL8 secretion in response to ST, and IL8 mRNA in response to ST and BL, but not LR. Furthermore, ST stimulated secretion of IL8 is inhibited basolaterally in the presence of BL.

Meso-Diaminopimelic Acid andMeso-Lanthionine, Amino Acids Specific to Bacterial Peptidoglycans, Activate Human Epithelial Cells through NOD1

Peptidoglycans (PGNs) are ubiquitous constituents of bacterial cell walls and exhibit various immunobiological activities. Two types of minimum essential PGN structures for immunobiological activities were chemically synthesized and designated as muramyldipeptide; N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) and gamma-D-glutamyl-meso-diaminopimelic acid (iE-DAP), which are common constituents of both Gram-positive and Gram-negative bacteria, as well as most Gram-negative and some Gram-positive bacteria, respectively. Recently, intracellular receptors for MDP and iE-DAP have been demonstrated to be nucleotide-binding oligomerization domain (NOD)1 and NOD2, respectively. In this study, we demonstrated that chemically synthesized meso-DAP itself activated human epithelial cells from various tissues, through NOD1 to generate antibacterial factors, PGN recognition proteins and beta-defensin 2, and cytokines in specified cases, although the activities of meso-DAP were generally weaker than those of known NOD agonists. However, stereoisomers of meso-DAP, LL-DAP, and DD-DAP were only slightly activated or remained inactive, respectively. Synthetic meso-lanthionine, which is another diamino-type amino acid specific to PGN of the specified Gram-negative bacteria, was also recognized by NOD1. In human monocytic cells, in the presence of cytochalasin D meso-DAP induced slightly but significantly increased production of cytokines, although the cells did not respond to meso-DAP in the absent of cytochalasin D. Our findings suggest that NOD1 is a special sentinel molecule, especially in the epithelial barrier, allowing the intracellular detection of bacteria through recognizing meso-DAP or comparable moiety of PGN from specified bacteria in cooperation with NOD2, thereby playing a key role in innate immunity.

Lyotropic liquid crystal as a real-time detector of microbial immune complexes

AIMS

To design a simple method for the detection of microbe-immune complexes exploiting the optical and elastic properties of a biocompatible liquid crystalline material.

METHODS AND RESULTS

Aqueous solution of disodium cromoglycate (DSCG), a lyotropic chromonic liquid crystal (LCLC), was aligned in a glass cell so as to be optically dark in polarized light. Immune complexes of at least three to four organisms altered the DSCG alignment such that polarized light was subsequently transmitted to reveal the presence of pathogens as optically bright regions around the immune complexes.

CONCLUSIONS

This work describes the first method to detect viable micro-organisms in real time using LCLC.

SIGNIFICANCE AND IMPACT OF THE STUDY

This technique provides a powerful tool for the detection of microbes in minutes, exploiting the optical and elastic properties of LC.

Tyzzer's disease in free-living cottontail rabbits (Sylvilagus floridanus) in Maryland

Complement-fixing (CF) antibody to Bacillus piliformis antigen was found in 9 of 14 (64%) serum samples obtained from cottontail rabbits (Sylvilagus floridanus) killed in the wild. CF antibody was not present in the serum of 8 cottontail rabbits trapped as juveniles in the same geographic areas and held in captivity for 4 years. Sero-negative cottontail rabbits died acutely with lesions typical of Tyzzer's disease following the intragastric administration of 10(3.8) ELD50 of B. piliformis spores. The possible influence of Tyzzer's disease upon the cyclic population pattern of cottontail rabbits in the wild is discussed. A hypothesis is presented that B. piliformis spores passed in the feces of diseased wild animals could contaminate pastures, hay and grain, and thereby serve as sources of infection to other animals.

Immunomodulatory effects ofBacillus firmus on mouse peritoneal cellsin Vitro

The effect of nonpathogenic G+ bacterium B. firmus (BF) on stimulation of mouse peritoneal cells in vitro was evaluated by testing nitric-oxide-synthesis induction and cytokine formation. The reactivity was compared of peritoneal cells from two inbred mouse strains, C57B1/6 and BALB/c, which differ in their immunological reactivity. Peritoneal macrophages from C57B1/6 produced more nitric oxide after a 1-d cultivation with inactivated BF than those of BALB/c mice. In both strains, production can be further increased by adding exogenous IFN-gamma to the culture. There were no significant differences between peritoneal cells of these two mouse strains in cytokine production after optimal in vitro stimulation with BF. BF effectively activated peritoneal cells for the production of TNF-alpha, IL-1beta and IL-10, delipidated bacterium (DBF) being more efficient than BF in induction of IL-10 and TNF-alpha. On the other hand, BF had only small effect on IFN-gamma production and no detectable effect on IL-12 production. Macrophage activation by BF/DBF can represent one of the mechanisms responsible for previously described immunomodulatory activity of BF.

Adjuvant effect ofBacillus firmus in intranasal immunization of guinea pigs with inactivated type B influenza virus

Intranasal immunization of guinea pigs with inactivated type B influenza virus plus inactivated Bacillus firmus as an adjuvant compared to the virus alone yields higher titers of serum hemagglutination-inhibiting antibodies and virus-neutralizing antibodies. This phenomenon could be useful in standard serology, especially in the preparation of immune sera against highly pathogenic strains for in vitro diagnosis.

Antiviral and immunoregulatory effect of a novel exopolysaccharide from a marine thermotolerant Bacillus licheniformis

EPS-1 is a novel extracellular polysaccharide produced by a strain of thermotolerant Bacillus licheniformis, isolated from a shallow marine hot spring of Vulcano Island (Italy). In this paper, antiviral and immunomodulatory effects of EPS-1 were evaluated. It was found that EPS-1 treatment impaired HSV-2 replication in human peripheral blood mononuclear cells (PBMC) but not in WISH cells. Since several cytokines modulate the immune response to viruses, Th1- and Th2-type cytokines were assayed in supernatants of PBMC in different experimental conditions. EPS-1 induced IL-12, IFN-gamma, IFN-alpha, TNF-alpha and IL-18, but not IL-4. Thus, the antiviral effect of EPS-1 on PBMC seems to be related to the pattern of cytokines induced.

Antiviral and immunoregulatory effect of a novel exopolysaccharide from a marine thermotolerant Bacillus licheniformis

EPS-1 is a novel extracellular polysaccharide produced by a strain of thermotolerant Bacillus licheniformis, isolated from a shallow marine hot spring of Vulcano Island (Italy). In this paper, antiviral and immunomodulatory effects of EPS-1 were evaluated. It was found that EPS-1 treatment impaired HSV-2 replication in human peripheral blood mononuclear cells (PBMC) but not in WISH cells. Since several cytokines modulate the immune response to viruses, Th1- and Th2-type cytokines were assayed in supernatants of PBMC in different experimental conditions. EPS-1 induced IL-12, IFN-gamma, IFN-alpha, TNF-alpha and IL-18, but not IL-4. Thus, the antiviral effect of EPS-1 on PBMC seems to be related to the pattern of cytokines induced.

Expression and secretion of the protective antigen of Bacillus anthracis in Bacillus brevis

We used the Bacillus brevis-pNU212 system to develop a mass production system for the protective antigen (PA) of Bacillus anthracis. A moderately efficient expression-secretion system for PA was constructed by fusing the PA gene from B. anthracis with the B. brevis cell-wall protein signal-peptide encoding region of pNU212, and by introducing the recombinant plasmid, pNU212-mPA, into B. brevis 47-5Q. The clone producing PA secreted about 300 microg of recombinant PA (rPA) per ml of 5PY-erythromycin medium after 4 days incubation at 30 degrees C. The rPA was fractionated from the culture supernatant of B. brevis 47-5Q carrying pNU212-mPA using ammonium sulfate at 70% saturation followed by anion exchange chromatography on a Hitrap Q, a Hiload 16/60 Superdex 200 gel filtration column and a phenyl sepharose hydrophobic interaction column, yielding 70 mg rPA per liter of culture. The N-terminal sequence of the purified rPA was identical to that of native PA from B. anthracis. The purified rPA exhibited cytotoxicity towards J774A.1 cells when combined with lethal factor. The rPA formulated in either Rehydragel HPA or MPL-TDM-CWS adjuvant (Ribi-Trimix) elicited the expression of a large amount of anti-PA and neutralizing antibodies in guinea pigs and completely protected them against a 100 LD50 challenge with fully virulent B. anthracis spores.

Intratracheal and intranasal immunization with ovalbumin conjugated withBacillus firmus as a carrier in mice

Inactivated Bacillus firmus (BF), G+ nonpathogenic bacterium of the external environment, was coupled to ovalbumin (OVA) and used in immunization experiments as antigen carrier. Balb/c mice were immunized thrice intra-tracheally and intra-nasally with conjugates of OVA and BF. Surprisingly, administration of OVA-BF conjugates inhibited anti-OVA IgG response in both sera and mucosal secretions if compared to an exposure to OVA alone. The suppression of antigen-specific antibody production was accompanied by promotion of TH1 phenotype.

Bacillus clausii exerts immuno-modulatory activity in allergic subjects: a pilot study

Bacillus clausii has been demonstrated to exert some immunomodulatory activities and to be safe. Allergic subjetcs show Th2 polarization and defect of T regulatory cells. Aim of the study was to investigate whether Bacillus clausii administration in allergic subjects might modulate cytokine pattern. Ten subjects (mean age 22.3 years) suffering from allergic rhinitis were enrolled. Bacillus clausii spores (Enterogermina: 2 billions spores/vial) were administered at the dosage schedule of 3 vials a day for 4 weeks. Nasal lavage was performed in all subjects before and after the treatment. A panel of cytokines, including IL4, IL10, IFNgamma, and TGFbeta, was measured by immunoassay in the fluid recovered from nasal lavage, before and after the treatment.

RESULTS

Bacillus clausii treatment showed a significant decrease of IL4 levels (p=0.004) and a significant increase of IFNgamma (p=0.038), TGFbeta (p=0.039), and IL10 (p=0.009) levels. In conclusion, this study shows that the Bacillus clausii may exert immuno-modulating activity by affecting cytokine pattern in allergic subjects and confirms previous study conducted in allergic children.

Bacillus alcalophilus peptidoglycan induces IFN-alpha-mediated inhibition of vaccinia virus replication

Bacterial products such as cell walls (CW) and peptidoglycan (PGN) are known to activate macrophages and NK cells during microbial infections. In this report, we demonstrated that whole CW and PGN of four Gram-positive bacteria are capable of enhancing the anti-poxviral activity of murine macrophage RAW 264.7 cells. Among the major Bacillus alcalophilus CW components, PGN contributes the most to antiviral activity and induces remarkably higher levels of IFN-alpha. Anti-IFN-alpha/beta antibody, but not anti-IFN-gamma, anti-IFN-gamma receptor, or anti-IL-12, reversed the PGN-induced inhibition of vaccinia virus replication and reduced nitric oxide (NO) production. Our data thus suggest that PGN induce antiviral activity through IFN-alpha and to a lesser extent, through NO production.

Bacillus globigii Bugbeads: A Model Simulant of a Bacterial Spore

Nonpathogenic microorganisms are often used as simulants of biological pathogens during the initial phase of detection method development. While these simulants approximate the size, shape, and cellular organization of the microorganism of interest, they do not resemble its surface protein content, a factor particularly important in methods based on immunorecognition. Here, we develop and detect an artificial bacterial spore--B. globigii (BG) Bugbead-a particle mimicking the antigenic surface of BG spores. Two methods of spore protein extraction were compared both quantitatively (by protein concentration assay) and qualitatively (by SDS-PAGE and Western blot): extraction by mechanical disruption and extraction by chemical decoating. The former method was more efficient in producing more protein and a greater number of antigens. BG Bugbeads were made by conjugating the extracted proteins to 0.8-microm carboxyl-coated polystyrene particles via carbodiimide coupling. BG Bugbeads were successfully detected by a bead-based enzyme-labeled immunoassay with fluorescence detection with a detection limit of 6.9 x 10(3) particles/mL. Formation of the Bugbead-capture bead complex was confirmed by ESEM. The concept of a harmless artificial spore can be applied to developing improved simulants for pathogenic spore-forming microorganisms such as B. anthracis, C. botulinum, and B. cereus, which can to be used for method validation, instrument calibration, and troubleshooting.

Chemical structure, conjugation, and cross-reactivity of Bacillus pumilus Sh18 cell wall polysaccharide

Bacillus pumilus strain Sh18 cell wall polysaccharide (CWP), cross-reactive with the capsular polysaccharide of Haemophilus influenzae type b, was purified and its chemical structure was elucidated using fast atom bombardment mass spectrometry, nuclear magnetic resonance techniques, and sugar-specific degradation procedures. Two major structures, 1,5-poly(ribitol phosphate) and 1,3-poly(glycerol phosphate), with the latter partially substituted by 2-acetamido-2-deoxy-alpha-galactopyranose (13%) and 2-acetamido-2-deoxy-alpha-glucopyranose (6%) on position O-2, were found. A minor component was established to be a polymer of -->3-O-(2-acetamido-2-deoxy-beta-glucopyranosyl)-1-->4-ribitol-1-OPO3-->. The ratios of the three components were 56, 34, and 10 mol%, respectively. The Sh18 CWP was covalently bound to carrier proteins, and the immunogenicity of the resulting conjugates was evaluated in mice. Two methods of conjugation were compared: (i) binding of 1-cyano-4-dimethylaminopyridinium tetrafluoroborate-activated hydroxyl groups of the CWP to adipic acid dihydrazide (ADH)-derivatized protein, and (ii) binding of the carbodiimide-activated terminal phosphate group of the CWP to ADH-derivatized protein. The conjugate-induced antibodies reacted in an enzyme-linked immunosorbent assay with the homologous polysaccharide and with a number of other bacterial polysaccharides containing ribitol and glycerol phosphates, including H. influenzae types a and b and strains of Staphylococcus aureus and Staphylococcus epidermidis.

Bacillus clausii probiotic strains: antimicrobial and immunomodulatory activities

The clinical benefits observed with probiotic use are mainly attributed to the antimicrobial substances produced by probiotic strains and to their immunomodulatory effects. Currently, the best-documented probiotic bacteria used in human therapy are lactic acid bacteria. In contrast, studies aiming to characterize the mechanisms responsible for the probiotic beneficial effects of Bacillus are rare. The current work seeks to contribute to such characterization by evaluating the antimicrobial and immunomodulatory activities of probiotic B. clausii strains. B. clausii strains release antimicrobial substances in the medium. Moreover, the release of these antimicrobial substances was observed during stationary growth phase and coincided with sporulation. These substances were active against Gram-positive bacteria, in particular against Staphylococcus aureus, Enterococcus faecium, and Clostridium difficile. The antimicrobial activity was resistant to subtilisin, proteinase K, and chymotrypsin treatment, whereas it was sensitive to pronase treatment. The evaluation of the immunomodulatory properties of probiotic B. clausii strains was performed in vitro on Swiss and C57 Bl/6j murine cells. The authors demonstrate that these strains, in their vegetative forms, are able to induce NOS II synthetase activity, IFN-gamma production, and CD4 T-cell proliferation.

Polyphasic characterization of Bacillus coagulans strains, illustrating heterogeneity within this species, and emended description of the species

Because of its food spoiling capacity on the one hand and its significant role in the production of industrially valuable products on the other, Bacillus coagulans is of economic concern. Several studies have revealed a great deal of diversity within the species and this has led to a number of taxonomic adjustments. The present study aims to clarify the diversity within Bacillus coagulans sensu stricto and determine the taxonomic status of the species. Therefore, a polyphasic study was performed on a set of B. coagulans strains from diverse habitats. Techniques as ARDRA, SDS-PAGE of whole cell proteins, FAME analysis, routine phenotypic tests and rep-PCR illustrate considerable intra-species heterogeneity, while 16S rDNA sequence comparison and DNA-DNA relatedness support the accommodation of these strains in one species. Although most techniques demonstrate appreciable heterogeneity among the Bacillus coagulans strains, the intraspecies groupings are not consistent throughout all the methods applied and are not supported by any economic, historic or practical traits. Therefore, a division in subspecies seems inappropriate. In attempt to achieve a better species delineation, an emended description of Bacillus coagulans is included.

Cytokines evaluation in nasal lavage of allergic children after Bacillus clausii administration: a pilot study

Respiratory infections are very frequent in children. Bacillus clausii has been demonstrated to exert some immunomodulatory activities and to be safe. We conducted a study to investigate whether B. clausii administration in allergic children with recurrent respiratory infections might modulate cytokine pattern. Ten children (mean age 4.4 yr) attending the nursery school were enrolled at the end of school year (i.e. in the summer). Bacillus clausii spores (Enterogermina): 2 billion spores per vial) were administered at the dosage schedule of two vials a day for 4 wk. A panel of cytokines, including interleukin (IL)-1, IL-3, IL-4, IL-6, IL-8, IL-10, IL-12, interferon (IFN)-gamma, transforming growth factor (TGF)-beta, and tumor necrosis factor (TNF)-alpha, was measured by immunoassay in the fluid recovered from nasal lavage, performed before and after the treatment. Bacillus clausii treatment induced a significant decrease of IL-4 levels (p < 0.01) and a significant increase of IFN-gamma (p < 0.05), IL-12 (p < 0.001), TGF-beta (p < 0.05), and IL-10 (p < 0.05) levels. Other cytokines were not significantly modified. In conclusion, this study shows that the B. clausii may exert immunomodulating activity by affecting cytokine pattern at nasal level in allergic children with recurrent respiratory infections.

Antiamylase-pullulanase enzyme monoclonals which specifically inhibit amylase or pullulanase activity

Monoclonal antibodies against amylase-pullulanase enzyme from Bacillus circulans F-2 have been produced to locate and characterize the catalytic sites of the enzyme. The antibodies have been examined for inhibition of both enzyme activities of amylase and pullulanase and then classified into four types: Type I which inhibited amylase activity, Type II which inhibited pullulanase activity, Type III which inhibited both enzyme activities, and Type IV which had no effect on either enzyme activity. Only two monoclonal antibodies (MAP-12 and MAP-17) as Type I and two antibodies (MAP-3 and MAP-5) as Type II were isolated. The inhibitory activities of the antibodies were characterized and compared. In Type II antibodies, the maximal demonstrated inhibition on the pullulanase activity was 88% for MAP-3 with 1 microg of antibody and 90% for MAP-5 with 2 microg of antibody, but did not inhibit the amylase activity. In Type I antibodies, in contrast, the maximal demonstrated inhibition on the amylase activity was 94% for MAP-12 and 97% for MAP-17 with 1 microg of antibody, respectively, but no inhibition of the pullulanase was noted. MAP-12 recognized sequential epitope, while MAP-17 recognized conformation-dependent epitope of amylase activity-related regions. However, both MAP-3 and MAP-5 recognized the conformation-dependent epitope of the pullulanase activity-related region. Furthermore, the antibodies of MAP-3, MAP-5, MAP-12, and MAP-17 did not compete with one another for binding to the enzyme, indicating that they have different target epitopes on the enzyme. Antibody binding of MAP-12 and MAP-17 to the enzyme was not specifically affected by any of the antiamylase compounds tested: (a) nojirimycin; and (b) 1-deoxynojirimycin. Kinetic analysis of their effects provides evidence that both antibodies of MAP-12 and MAP-17 decrease the catalytic rate of enzyme activity and have little or no effect on substrate binding.

Role of T cells in the adjuvant effect of Bacillus firmus on the immune system of mice: intranasal and intratracheal immunization study with ovalbumin

Functions of T cells were determined after intranasal and intratracheal immunization of mice with ovalbumin (Ova) and Bacillus firmus (Bf), a Gram-positive nonpathogenic bacterium of the external environment, or delipidated Bf (dBf) as adjuvants, with the aim to elucidate the mechanism of support of Ova-specific antibody production caused by Bf that had been observed in an identical experiment. Neither Bf nor dBf in a mixture with Ova stimulated Ova-specific T-cell response tested as antigen-specific blast transformation. By contrast, a mild polyclonal stimulation was observed in splenocytes from mice given dBf. In vitro incubation of splenocytes with 100 micrograms (but not 10 micrograms) of Bf or dBf led to a highly significant inhibition of proliferation below the control level in all groups of animals. Supernatants of splenocyte cultures were further tested for cytokine production. IL-10 and IFN-gamma were released after in vitro challenge with dBf and in some cases also with Bf. Analysis of sera demonstrated that administration of Ova + adjuvant brought about an increase in anti-Ova IgG1, IgG2a and IgG2b whereas treatment with Ova alone caused a rise in IgG1 only. The role of Bf or dBf in the enhancement of antigen-specific antibody production could be in influencing macrophages and inducing cytokine milieu composed of IL-10, IFN-gamma and other factors that leads to a bystander stimulation of specifically activated Ova-B cell receptor (Ova-BCR)-bearing cells.

Bacillus spores for vaccine delivery

Spores of the genus Bacillus have been used for a long time as probiotics for oral bacteriotherapy both in humans and in animals. Spores are also employed in a veterinary vaccine against anthrax. Despite this long lasting and extensive use, the specific contribution of spores to the beneficial effects of probiotics and to the immunogenicity of the vaccine is not completely elucidated. This review focuses on the different aspects of the use of spore preparations. In particular the use of recombinant spores as vaccine delivery vehicles is described and discussed.

Immunostimulatory effect of Bacillus firmus on mouse lymphocytes

Bacillus firmus (a Gram-positive nonpathogenic and harmless bacterium), was shown to be a strong polyclonal activator of mouse B lymphocytes as estimated by ELISA testing of Ig concentrations in culture supernatants after incubation of BALB/c mouse splenocytes with inactivated bacillus. Synthesis of all main Ig classes and all IgG subclasses was stimulated in vitro, the considerable effect on IgA formation being the most interesting feature. B cell stimulation was T cell dependent, as was demonstrated by the effect of B. firmus on all Ig isotypes and by comparison of lymphocyte response of nu/nu mice and heterozygous nu/+ mice. The effect of B. firmus on splenocyte proliferation was stimulatory or suppressive depending on the dose of the bacterium. Increased synthesis of IFN-gamma and IL-10 (detected by ELISA in splenocyte culture supernatants) showed probable stimulation of Th1 and Th2 subpopulations. Considering the stimulatory effect on IgA formation and macrophage stimulation, B. firmus seems to be a prospective mucosal adjuvant and/or probiotic.

A miniature biochip system for detection of aerosolized Bacillus globigii spores

The feasibility of using a novel detection scheme for the analysis of biological warfare agents is demonstrated using Bacillus globigii spores, a surrogate species for Bacillus anthracis. In this paper, a sensitive and selective enzyme-linked immunosorbent assay using a novel fluorogenic alkaline phosphatase substrate (dimethylacridinone phosphate) is combined with a compact biochip detection system, which includes a miniature diode laser for excitation. Detection of aerosolized spores was achieved by coupling the miniature system to a portable bioaerosol sampler, and the performance of the antibody-based recognition and enzyme amplification method was evaluated. The bioassay performance was found to be compatible with the air sampling device, and the enzymatic amplification was found to be an attractive amplification method for detection of low spore concentrations. The combined portable bioaerosol sampler and miniature biochip system detected 100 B. globigii spores, corresponding to 17 aerosolized spores/L of air. Moreover, the incorporation of the miniature diode laser with the self-contained biochip design allows for a compact system that is readily adaptable to field use. In addition, these studies have included investigations into the tradeoff between assay time and sensitivity.

Analysis of the heat-adaptive response of psychrotrophic Bacillus weihenstephanensis

The heat-adaptive response of the psychrotrophic spoilage bacterium Bacillus weihenstephanensis DSM11827 is described. It is demonstrated that vegetative cells of B. weihenstephanensis adapts to heat exposure at 47 degrees C by prior exposure to heat at the nonlethal temperature of 38 degrees C. For this adaptive response, protein synthesis is required and maximum adaptation was noted after 15 min to 2 h prior exposure at 38 degrees C. By using two-dimensional gel electrophoresis (2D-E), an overview of the heat-shock proteins (HSPs) of B. weihenstephanensis was obtained and it was shown that the production of 15 proteins increased upon exposure to 38 degrees C. In more detail, the use of specific antibodies revealed induction of the HSPs DnaK, DnaJ, GroEL, ClpC, ClpP and ClpX of B. weihenstephanensis. In addition, also pre-exposure to other stresses than heat, such as exposure to a high salt concentration, low pH, a high ethanol concentration or low temperature, resulted in development of increased heat tolerance of B. weihenstephanensis, and during these conditions, an increased production of some HSPs was noted. This phenomenon of cross-protection might be of substantial importance in relation to the design of safe minimal processing regimes.

Human antibodies against spores of the genus Bacillus: a model study for detection of and protection against anthrax and the bioterrorist threat

A naive, human single-chain Fv (scFv) phage-display library was used in bio-panning against live, native spores of Bacillus subtilis IFO 3336 suspended in solution. A direct in vitro panning and enzyme-linked immunosorbent assay-based selection afforded a panel of nine scFv-phage clones of which two, 5B and 7E, were chosen for further study. These two clones differed in their relative specificity and affinity for spores of B. subtilis IFO 3336 vs. a panel of spores from 11 other Bacillus species/strains. A variety of enzyme-linked immunosorbent assay protocols indicated these scFv-phage clones recognized different spore epitopes. Notably, some spore epitopes markedly changed between the free and microtiter-plate immobilized state as revealed by antibody-phage binding. An additional library selection procedure also was examined by constructing a Fab chain-shuffled sublibrary from the nine positive clones and by using a subtractive panning strategy to remove crossreactivity with B. licheniformis 5A24. The Fab-phage clone 52 was improved compared with 5B and was comparable to 7E in binding B. subtilis IFO 3336 vs. B. licheniformis 5A24, yet showed a distinctive crossreactivity pattern with other spores. We also developed a method to directly detect individual spores by using fluorescently labeled antibody-phage. Finally, a variety of "powders" that might be used in deploying spores of B. anthracis were examined for antibody-phage binding. The strategies described provide a foundation to discover human antibodies specific for native spores of B. anthracis that can be developed as diagnostic and therapeutic reagents.