Aguilera, M; Cerdà-Cuéllar, M; Martínez, V
Alterations in the composition of the commensal microbiota (dysbiosis) seem to be a pathogenic component of functional gastrointestinal disorders, mainly irritable bowel syndrome (IBS), and might participate in the secretomotor and sensory alterations observed in these patients.We determined if a state antibiotics-induced intestinal dysbiosis is able to modify colonic pain-related and motor responses and characterized the neuro-immune mechanisms implicated in mice. A 2-week antibiotics treatment induced a colonic dysbiosis (increments in Bacteroides spp, Clostridium coccoides and Lactobacillus spp and reduction in Bifidobacterium spp). Bacterial adherence was not affected. Dysbiosis was associated with increased levels of secretory-IgA, up-regulation of the antimicrobial lectin RegIIIγ, and toll-like receptors (TLR) 4 and 7 and down-regulation of the antimicrobial-peptide Resistin-Like Molecule-β and TLR5. Dysbiotic mice showed less goblet cells, without changes in the thickness of the mucus layer. Neither macroscopical nor microscopical signs of inflammation were observed. In dysbiotic mice, expression of the cannabinoid receptor 2 was up-regulated, while the cannabinoid 1 and the mu-opioid receptors were down-regulated. In antibiotic-treated mice, visceral pain-related responses elicited by intraperitoneal acetic acid or intracolonic capsaicin were significantly attenuated. Colonic contractility was enhanced during dysbiosis. Intestinal dysbiosis induce changes in the innate intestinal immune system and modulate the expression of pain-related sensory systems, an effect associated with a reduction in visceral pain-related responses. Commensal microbiota modulates gut neuro-immune sensory systems, leading to functional changes, at least as it relates to viscerosensitivity. Similar mechanisms might explain the beneficial effects of antibiotics or certain probiotics in the treatment of IBS. PMID:25531553
Siggers, Richard H; Siggers, Jayda; Boye, Mette; Thymann, Thomas; Mølbak, Lars; Leser, Thomas; Jensen, Bent B; Sangild, Per T
Following preterm birth, bacterial colonization and enteral formula feeding predispose neonates to gut dysfunction and necrotizing enterocolitis (NEC), a serious gastrointestinal inflammatory disease. We hypothesized that administration of probiotics would beneficially influence early bacterial colonization, thereby reducing the susceptibility to formula-induced gut atrophy, dysfunction, and NEC. Caesarean-delivered preterm pigs were provided total parenteral nutrition (1.5 d) followed by enteral feeding (2 d) with porcine colostrum (COLOS; n = 5), formula (FORM; n = 9), or formula with probiotics (FORM-P; Bifidobacterium animalis and Lactobacillus: L. acidophilus, L. casei, L. pentosus, L. plantarum; n = 13). Clinical NEC scores were reduced (P < 0.05) in FORM-P (2.0 +/- 0.2) and COLOS groups (1.7 +/- 0.5) compared with FORM pigs (3.4 +/- 0.6). Lower NEC scores were associated with elevated intestinal weight, mucosa proportion, villus height, RNA integrity, and brush border aminopeptidase A and N activities, and lower gastric organic acid concentration in the FORM-P and COLOS groups (P < 0.05). Diversity of the mucosa-associated bacteria in the distal small intestine was similar among formula-fed pigs, yet the abundance of specific bacterial groups differed between FORM-P and FORM pigs. FORM-P pigs had lower colonization density of a potential pathogen, Clostridium perfringens, and had commensal Lactobacillus bacteria more closely associated with enterocytes along the villus-crypt axis relative to FORM pigs. These results suggest that probiotic administration immediately after birth promotes the colonization of a beneficial commensal microbiota capable of limiting the formula-induced mucosal atrophy, dysfunction, and pathogen load in preterm neonates, thereby reducing the incidence and severity of NEC. PMID:18641188
Cilieborg, Malene S.; Boye, Mette; Mølbak, Lars;
Necrotizing enterocolitis (NEC) in preterm neonates is dependent on bacterial colonization, but it remains unclear whether a particular microbiota or specific pathogens are involved. We hypothesized that gut colonization differs between preterm and term neonates and that overgrowth of Clostridium...
Jefferson Lessa Soares de Macedo
Full Text Available A prospective study of fungal and bacterial flora of burn wounds was carried out from February 2004 to February 2005 at the Burns Unit of Hospital Regional da Asa Norte, Brasília, Brazil. During the period of the study, 203 patients were treated at the Burns Unit. Wound swab cultures were assessed at weekly intervals for four weeks. Three hundred and fifty four sampling procedures (surface swabs were performed from the burn wounds. The study revealed that bacterial colonization reached 86.6% within the first week. Although the gram-negative organisms, as a group, were more predominant, Staphylococcus aureus (28.4% was the most prevalent organism in the first week. It was however surpassed by Pseudomonas aeruginosa form third week onwards. For S. aureus and P. aeruginosa vancomycin and polymyxin were found to be the most effective drugs. Most of the isolates showed high level resistance to antimicrobial agents. Fungi were found to colonize the burn wound late during the second week postburn, with a peak incidence during the third and fourth weeks. Species identification of fungi revealed that Candida tropicalis was the most predominant, followed by Candida parapsilosis. It is crucial for every burn institution to determine the specific pattern of burn wound microbial colonization, the time-related changes in the dominant flora, and the antimicrobial sensitivity profiles. This would enable early treatment of imminent septic episodes with proper empirical systemic antibiotics, without waiting for culture results, thus improving the overall infection-related morbidity and mortality.
Siggers, Richard H.; Siggers, Jayda; Boye, Mette;
colonization, thereby reducing the susceptibility to formula-induced gut atrophy, dysfunction, and NEC. Caesarean-delivered preterm pigs were provided total parenteral nutrition (1.5 d) followed by enteral feeding (2d) with porcine colosstrum (COLOS; n= 5), formula (FORM; n = 9), or formula with probiotics...
Full Text Available Bacterial colonization was investigated retrospectively in patients with plaque psoriasis (n=98 inpatient treatments, n=73 patients. At least one pathogen was found in 46% of all cases. Staphylococcus aureus was the most frequent bacterium. Bacterial colonization of psoriasis plaques could be relevant in individual cases.
Full Text Available Microorganisms have been reported to be associated with the alteration of the glassy margin of seafloor pillow basalts (Thorseth et al., 2001, 2003; Lysnes et al., 2004. The amount of iron and other biological important elements present in basalts and the vast abundance of basaltic glass in the earth's crust, make glass alteration an important process in global element cycling. To gain further insight into microbial communities associated with glass alteration, five microcosm experiments mimicking seafloor conditions were inoculated with seafloor basalt and incubated for one year. Mineral precipitations, microbial attachment to the glass and glass alteration were visualized by scanning electron microscopy (SEM, and the bacterial community composition was fingerprinted by PCR and denaturing gradient gel electrophoresis (DGGE in combination with sequencing. SEM analysis revealed a microbial community with low morphological diversity of mainly biofilm associated and prosthecate microorganisms. Approximately 30 nm thick alteration rims developed on the glass in all microcosms after one year of incubation; this however was also seen in non inoculated controls. Calcium carbonate precipitates showed parallel, columnar and filamentous crystallization habits in the microcosms as well as in the sterile controls. DGGE analysis showed an alteration in bacterial community profiles in the five different microcosms, as a response to the different energy and redox regimes and time. In all microcosms a reduction in number of DGGE bands, in combination with an increase in cell abundance were recorded during the experiment. Sequence analysis showed that the microcosms were dominated by four groups of organisms with phylogenetic affiliation to four taxa: The Rhodospirillaceae, a family containing phototrophic marine organisms, in which some members are capable of heterotrophic growth in darkness and N2 fixation; the family Hyphomicrobiaceae, a group
Einen, J.; Kruber, C.; Øvreås, L.; Thorseth, I. H.; Torsvik, T.
Microorganisms have been reported to be associated with the alteration of the glassy margin of seafloor pillow basalts (Thorseth et al., 2001, 2003; Lysnes et al., 2004). The amount of iron and other biological important elements present in basalts and the vast abundance of basaltic glass in the earth's crust, make glass alteration an important process in global element cycling. To gain further insight into microbial communities associated with glass alteration, five microcosm experiments mimicking seafloor conditions were inoculated with seafloor basalt and incubated for one year. Mineral precipitations, microbial attachment to the glass and glass alteration were visualized by scanning electron microscopy (SEM), and the bacterial community composition was fingerprinted by PCR and denaturing gradient gel electrophoresis (DGGE) in combination with sequencing. SEM analysis revealed a microbial community with low morphological diversity of mainly biofilm associated and prosthecate microorganisms. Approximately 30 nm thick alteration rims developed on the glass in all microcosms after one year of incubation; this however was also seen in non inoculated controls. Calcium carbonate precipitates showed parallel, columnar and filamentous crystallization habits in the microcosms as well as in the sterile controls. DGGE analysis showed an alteration in bacterial community profiles in the five different microcosms, as a response to the different energy and redox regimes and time. In all microcosms a reduction in number of DGGE bands, in combination with an increase in cell abundance were recorded during the experiment. Sequence analysis showed that the microcosms were dominated by four groups of organisms with phylogenetic affiliation to four taxa: The Rhodospirillaceae, a family containing phototrophic marine organisms, in which some members are capable of heterotrophic growth in darkness and N2 fixation; the family Hyphomicrobiaceae, a group of prosthecate oligotrophic
Cilieborg, Malene S.; Boye, Mette; Sangild, Per Torp
Necrotizing enterocolitis (NEC) develops in 5–10% of preterm infants in association with enteral feeding and bacterial colonization. It remains unclear how diet and bacteria interact to protect or provoke the immature gastrointestinal tract. Understanding the factors that control bacterial...
Franzenburg, Sören; Fraune, Sebastian; Altrock, Philipp M; Künzel, Sven; Baines, John F; Traulsen, Arne; Bosch, Thomas C G
Animals are colonized by complex bacterial communities. The processes controlling community membership and influencing the establishment of the microbial ecosystem during development are poorly understood. Here we aimed to explore the assembly of bacterial communities in Hydra with the broader goal of elucidating the general rules that determine the temporal progression of bacterial colonization of animal epithelia. We profiled the microbial communities in polyps at various time points after hatching in four replicates. The composition and temporal patterns of the bacterial communities were strikingly similar in all replicates. Distinct features included high diversity of community profiles in the first week, a remarkable but transient adult-like profile 2 weeks after hatching, followed by progressive emergence of a stable adult-like pattern characterized by low species diversity and the preponderance of the Betaproteobacterium Curvibacter. Intriguingly, this process displayed important parallels to the assembly of human fecal communities after birth. In addition, a mathematical modeling approach was used to uncover the organizational principles of this colonization process, suggesting that both, local environmental or host-derived factor(s) modulating the colonization rate, as well as frequency-dependent interactions of individual bacterial community members are important aspects in the emergence of a stable bacterial community at the end of development. PMID:23344242
OBJECTIVE: To optimize total bacterial 16S rRNA quantification in microdissected colonic crypts in healthy controls and patients with ulcerative colitis (UC) and to characterize the findings with disease activity. BACKGROUND: Microscopic and molecular techniques have recently converged to allow bacterial enumeration in remote anatomic locations [eg, crypt-associated mucous gel (CAMG)]. The aims of this study were to combine laser capture microdissection (LCM) and 16S rRNA-based quantitative polymerase chain reaction (qPCR) to determine total bacterial copy number in CAMG both in health and in UC and to characterize the findings with disease activity. METHODS: LCM was used to microdissect CAMG from colonic mucosal biopsies from controls (n = 20) and patients with acute (n = 10) or subacute (n = 10) UC. Pan-bacterial 16S rRNA copy number per millimeter square in samples from 6 locations across the large bowel was obtained by qPCR using Desulfovibrio desulfuricans as a reference strain. Copy numbers were correlated with the UC disease activity index (UCDAI) and the simple clinical colitis activity index (SCCAI). RESULTS: Bacterial colonization of CAMG was detectable in all groups. Copy numbers were significantly reduced in acute UC. In subacute colitis, there was a positive correlation between copy number and UCDAI and SCCAI in the ascending, transverse and sigmoid colon. CONCLUSIONS: This study describes a sensitive method of quantitatively assessing bacterial colonization of the colonic CAMG. A positive correlation was found between CAMG bacterial load and subacute disease activity in UC, whereas detectable bacterial load was reduced in acute UC.
Kandel, Christopher E; Simor, Andrew E; Donald A Redelmeier
Background: Elevators are ubiquitous and active inside hospitals, potentially facilitating bacterial transmission. The objective of this study was to estimate the prevalence of bacterial colonization on elevator buttons in large urban teaching hospitals. Methods: A total of 120 elevator buttons and 96 toilet surfaces were swabbed over separate intervals at 3 tertiary care hospitals on weekdays and weekends in Toronto, Ontario. For the elevators, swabs were taken from 2 interior buttons (butto...
Cilieborg, Malene S; Boye, Mette; Sangild, Per T
Necrotizing enterocolitis (NEC) develops in 5-10% of preterm infants in association with enteral feeding and bacterial colonization. It remains unclear how diet and bacteria interact to protect or provoke the immature gastrointestinal tract. Understanding the factors that control bacterial colonization may provide the clue to prevent NEC, and studies in infants must be combined with animal models to understand the mechanisms of the microbiota-epithelium interactions. Analyses of infant fecal samples show that the density and distribution of bacterial species are highly variable with no consistent effects of gestational age, delivery mode, diet or probiotic administration, while low bacterial diversity and bacterial overgrowth are commonly associated with NEC. A series of recent studies in preterm pigs show that the mucosa-associated microbiota is affected by delivery method, prematurity and NEC progression and that diet has limited effects. Overgrowth of specific groups (e.g. Clostridia) appears to be a consequence of NEC, rather than the cause of NEC. Administration of probiotics either decreases or increases NEC sensitivity in preterm pigs, while in preterm infants probiotics have generally decreased NEC incidence and overall mortality. The optimal nature and amount of probiotic bacteria are unknown and host defense factors appear more important for NEC sensitivity than the nature of the gut microbiota. Host defense is improved by feeding the optimal amount of enteral diets, such as mother's colostrum or milk, that help the immature intestinal immune system to respond appropriately to the highly variable bacterial colonization. PMID:22284985
Pacheco, Alline R.; Curtis, Meredith M.; Ritchie, Jennifer M; Munera, Diana; Matthew K Waldor; Moreira, Cristiano G.; Sperandio, Vanessa
The mammalian gastrointestinal (GI) tract provides a complex and competitive environment for the microbiota 1 . Successful colonization by pathogens depends on scavenging nutrients, sensing chemical signals, competing with the resident bacteria, and precisely regulating expression of virulence genes 2 . The GI pathogen enterohemorrhagic E.coli (EHEC) relies on inter-kingdom chemical sensing systems to regulate virulence gene expression 3–4 . Here we show that these systems control the express...
Audebert, Christophe; Even, Gaël; Cian, Amandine; ,; Safadi, Dima El; Certad, Gabriela; Delhaes, Laurence; Pereira, Bruno; Nourrisson, Céline; Poirier, Philippe; Wawrzyniak, Ivan; Delbac, Frédéric; Morelle, Christelle; Bastien, Patrick; Lachaud, Laurence
Alterations in the composition of commensal bacterial populations, a phenomenon known as dysbiosis, are linked to multiple gastrointestinal disorders, such as inflammatory bowel disease and irritable bowel syndrome, or to infections by diverse enteric pathogens. Blastocystis is one of the most common single-celled eukaryotes detected in human faecal samples. However, the clinical significance of this widespread colonization remains unclear, and its pathogenic potential is controversial. To ad...
Audebert, Christophe; Even, Gaël; Cian, Amandine; Loywick, Alexandre; Merlin, Sophie; Viscogliosi, Eric; Chabé, Magali
Alterations in the composition of commensal bacterial populations, a phenomenon known as dysbiosis, are linked to multiple gastrointestinal disorders, such as inflammatory bowel disease and irritable bowel syndrome, or to infections by diverse enteric pathogens. Blastocystis is one of the most common single-celled eukaryotes detected in human faecal samples. However, the clinical significance of this widespread colonization remains unclear, and its pathogenic potential is controversial. To address the issue of Blastocystis pathogenicity, we investigated the impact of colonization by this protist on the composition of the human gut microbiota. For that purpose, we conducted a cross-sectional study including 48 Blastocystis-colonized patients and 48 Blastocystis-free subjects and performed an Ion Torrent 16S rDNA gene sequencing to decipher the Blastocystis-associated gut microbiota. Here, we report a higher bacterial diversity in faecal microbiota of Blastocystis colonized patients, a higher abundance of Clostridia as well as a lower abundance of Enterobacteriaceae. Our results contribute to suggesting that Blastocystis colonization is usually associated with a healthy gut microbiota, rather than with gut dysbiosis generally observed in metabolic or infectious inflammatory diseases of the lower gastrointestinal tract. PMID:27147260
Znachor, Petr; Šimek, Karel; Nedoma, Jiří
Roč. 66, č. 1 (2012), s. 87-94. ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA206/08/0015; GA ČR(CZ) GAP504/11/2177; GA ČR(CZ) GAP504/11/2182 Institutional research plan: CEZ:AV0Z60170517 Keywords : PDMPO * bacterial colonization * diatoms * Fragilaria crotonensis * flood * reservoir Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.037, year: 2012
Cilieborg, Malene S; Boye, Mette; Mølbak, Lars; Thymann, Thomas; Sangild, Per T
Necrotizing enterocolitis (NEC) in preterm neonates is dependent on bacterial colonization, but it remains unclear whether a particular microbiota or specific pathogens are involved. We hypothesized that gut colonization differs between preterm and term neonates and that overgrowth of Clostridium perfringens predisposes to NEC. By using terminal-RFLP and FISH, we characterized the gut microbiota of preterm, caesarean-delivered, formula-fed pigs (n = 44) with or without NEC and of formula- or colostrum-fed term, and vaginally born pigs (n = 13). A different microbiota with high C. perfringens abundance was observed in preterm pigs with NEC compared with healthy individuals. However, immunization against C. perfringens toxins did not prevent NEC, and C. perfringens inoculation (3.6 × 10 cfu/d) failed to induce NEC (n = 16), whereas prophylactic broad-spectrum antibiotics treatment prevented NEC (n = 24). Colonization in both groups of term pigs differed from preterm pigs and was dominated by Lactobacilli spp. In conclusion, gestational age (GA) and NEC influence neonatal gut colonization, whereas diet has minor effects. C. perfringens is more abundant in pigs with NEC but rather as a consequence than a cause of disease. The general bacterial load and underdeveloped gut immune responses in preterm neonates seem more important for NEC development than specific pathogens. PMID:20924317
Kramer, Andrew M; Lyons, M Maille; Dobbs, Fred C; Drake, John M
Organic aggregates provide a favorable habitat for aquatic microbes, are efficiently filtered by shellfish, and may play a major role in the dynamics of aquatic pathogens. Quantifying this role requires understanding how pathogen abundance in the water and aggregate size interact to determine the presence and abundance of pathogen cells on individual aggregates. We build upon current understanding of the dynamics of bacteria and bacterial grazers on aggregates to develop a model for the dynamics of a bacterial pathogen species. The model accounts for the importance of stochasticity and the balance between colonization and extinction. Simulation results suggest that while colonization increases linearly with background density and aggregate size, extinction rates are expected to be nonlinear on small aggregates in a low background density of the pathogen. Under these conditions, we predict lower probabilities of pathogen presence and reduced abundance on aggregates compared with predictions based solely on colonization. These results suggest that the importance of aggregates to the dynamics of aquatic bacterial pathogens may be dependent on the interaction between aggregate size and background pathogen density, and that these interactions are strongly influenced by ecological interactions and pathogen traits. The model provides testable predictions and can be a useful tool for exploring how species-specific differences in pathogen traits may alter the effect of aggregates on disease transmission. PMID:24340173
Newton C M Gomes
Full Text Available BACKGROUND: Mangrove forests are of global ecological and economic importance, but are also one of the world's most threatened ecosystems. Here we present a case study examining the influence of the rhizosphere on the structural composition and diversity of mangrove bacterial communities and the implications for mangrove reforestation approaches using nursery-raised plants. METHODOLOGY/PRINCIPAL FINDINGS: A barcoded pyrosequencing approach was used to assess bacterial diversity in the rhizosphere of plants in a nursery setting, nursery-raised transplants and native (non-transplanted plants in the same mangrove habitat. In addition to this, we also assessed bacterial composition in the bulk sediment in order to ascertain if the roots of mangrove plants affect sediment bacterial composition. We found that mangrove roots appear to influence bacterial abundance and composition in the rhizosphere. Due to the sheer abundance of roots in mangrove habitat, such an effect can have an important impact on the maintenance of bacterial guilds involved in nutrient cycling and other key ecosystem functions. Surprisingly, we also noted a marked impact of initial nursery conditions on the rhizosphere bacterial composition of replanted mangrove trees. This result is intriguing because mangroves are periodically inundated with seawater and represent a highly dynamic environment compared to the more controlled nursery environment. CONCLUSIONS/SIGNIFICANCE: In as far as microbial diversity and composition influences plant growth and health, this study indicates that nursery conditions and early microbial colonization patterns of the replants are key factors that should be considered during reforestation projects. In addition to this, our results provide information on the role of the mangrove rhizosphere as a habitat for bacteria from estuarine sediments.
Wirth, Stacy M; Bertuccio, Alex J; Cao, Feng; Lowry, Gregory V; Tilton, Robert D
Immobilization of antimicrobial silver nanoparticles (AgNPs) on surfaces has been proposed as a method to inhibit biofouling or as a possible route by which incidental releases of AgNPs may interfere with biofilms in the natural environment or in wastewater treatment. This study addresses the ability of planktonic Pseudomonas fluorescens bacteria to colonize surfaces with pre-adsorbed AgNPs. The ability of the AgNP-coated surfaces to inhibit colonization was controlled by the dissolved silver in the system, with a strong dependence on the initial planktonic cell concentration in the suspension, i.e., a strong inoculum effect. This dependence was attributed to a decrease in dissolved silver ion bioavailability and toxicity caused by its binding to cells and/or cell byproducts. Therefore, when the initial cell concentration was high (∼1×10(7)CFU/mL), an excess of silver binding capacity removed most of the free silver and allowed both planktonic growth and surface colonization directly on the AgNP-coated surface. When the initial cell concentration was low (∼1×10(5)CFU/mL), 100% killing of the planktonic cell inoculum occurred and prevented colonization. When an intermediate initial inoculum concentration (∼1×10(6)CFU/mL) was sufficiently large to prevent 100% killing of planktonic cells, even with 99.97% initial killing, the planktonic population recovered and bacteria colonized the AgNP-coated surface. In some conditions, colonization of AgNP-coated surfaces was enhanced relative to silver-free controls, and the bacteria demonstrated a preferential attachment to AgNP-coated, rather than bare, surface regions. The degree to which the bacterial concentration dictates whether or not surface-immobilized AgNPs can inhibit colonization has significant implications both for the design of antimicrobial surfaces and for the potential environmental impacts of AgNPs. PMID:26771749
Kiørboe, Thomas; Grossart, H.P.; Ploug, H.;
Quantifying the rate at which bacteria colonize aggregates is a key to understanding microbial turnover of aggregates. We used encounter models based on random walk and advection-diffusion considerations to predict colonization rates from the bacteria's motility patterns (swimming speed, tumbling...... (0 to 2 s(-1)). The rates at which these bacteria colonized artificial aggregates (stationary and sinking) largely agreed with model predictions. We report several findings. (i) Motile bacteria rapidly colonize aggregates, whereas nonmotile bacteria do not. 00 Flow enhances colonization rates. (iii...
Tursi, Antonio; Brandimarte, Giovanni; Giorgetti, Gian Marco; Elisei, Walter
AIM: Small intestinal bacterial overgrowth (SIBO) may contribute to the appearance of several gastrointestinal nonspecific symptoms. Acute diverticulitis is affected by some similar symptoms and bacterial colonic overgrowth. We assessed the prevalence of SIBO in acute uncomplicated diverticulitis and evaluated its influence on the clinical course of the disease.
Full Text Available We investigated whether Clostridium difficile toxin alters colonic tissue levels of vasoactive intestinal peptide (VIP at the expense of changes in colonic motility in the isolated perfused rabbit left colon. Colonic inflammation was induced by the intracolonic administration of 10−8 M C. difflcile toxin. Strain gauge transducers were sewn onto the serosal surface of the colon to evaluate colonic motility. C. difflcile administration produced histologic changes consistent with epithelial damage. This was associated with an increased production of prostaglandin E2 and thromboxane B2. Tissue levels of VIP but not substance P were significantly reduced. This was associated with an increased number of contractions per minute and an average force of each colonic contraction. These results suggest that tissue levels of VIP are suppressed by C. difflcile and may participate in colonic dysmotility during active inflammation.
Altenburger, Andreas; Ekelund, Flemming; Jacobsen, Carsten Suhr
We know little about the ability of protozoa to colonize soils, including their successional patterns. To elucidate this issue, we investigated in which order different protozoan morpho-types colonize sterile soil. We used sterilized soils with different carbon content, and exposed them...
Diergaarde, B.; Vrieling, A.; Kraats, van A.A.; Muijen, van G.N.P.; Kok, F.J.; Kampman, E.
Cigarette smoking has been inconsistently associated with colon cancer risk. To evaluate the hypothesis that smoking is primarily linked to a specific colon tumor subgroup(s), we assessed associations between smoking and the occurrence of mutations in the APC, K-ras and p53 genes, p53 overexpression
Chu, Xian-Ming; An, Yi; Li, Xue-Bin; Guo, Ji-Hong
Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs) is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases); the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%). Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases), and bacterial DNA was detected on the device in 29.5% of patients (23 cases). During follow-up (median 24.6 months), two patients (6.7%, 2/30) became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization. PMID:25530969
Full Text Available Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases; the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%. Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases, and bacterial DNA was detected on the device in 29.5% of patients (23 cases. During follow-up (median 24.6 months, two patients (6.7%, 2/30 became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization.
Irradiation increases susceptibility to bacterial infection. Exogenous proinflammatory cytokines can alter the response of mice to γradiation, but the role of endogenous inflammatory cytokines after bacterial infection in irradiated animals is not known. Gene expression of hematopoietic (GM-CSF) and proinflammatory (IL-1β, IL-6 and TNF-α) cytokines were examined in spleens of B6D2F1/J female mice after irradiation alone (1.0- and 7.0-Gy), and after irradiation followed by Klebsiella pneumoniae s.c. challenge 4 days postirradiation by using the reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot hybridization. At 4, 8, and 24 h after bacterial challenge in 7.0-Gy-irradiated mice, GM-CSF mRNA increased (p<0.05). TNF-α mRNA in irradiated mice were slightly decreased, whereas after bacterial challenge, TNF-α mRNA elevated at 30 h in 7.0-Gy-irradiated mice; at 4, and 8 h in 1.0-Gy-irradiated mice, and at 1 h in sham-irradiated mice (p<0.05). IL-6 mRNA displayed a biphasic response in 7.0-Gy-irradiated mice, and, after bacterial challenge, in both irradiated mice (1.0- and 7.0-Gy) and sham-irradiated mice. IL-1β mRNA remained at or below normal for 8 h and increased at 24 h after bacterial challenge on day 4 in 7.0-Gy-irradiated mice. These results indicate that sublethal gamma radiation alters the patterns of the hematopoietic and proinflammatory cytokine responses to bacterial challenge in vivo. Consequently, treatment protocols may need to take into account changes in cytokine gene responses to resolve infection after irradiation. (author)
Pantoea stewartii subsp. stewartii, the etiological agent of Stewart's wilt, is a bacterial pathogen of sweet corn which colonizes both the apoplast and xylem tissues. During the initial stages of the infection process, the pathogen forms water-soaked lesions through lysis of the plant cells, followed by colonization of the xylem tissue where it can grow to high cell densities and form biofilms. Biofilm formation within the xylem vessels can block water flow, causing the characteristic wiltin...
Mushtaq Ahmad Laway
Full Text Available Background: The aim of this study was to assess the pattern of periurethral bacterial flora in uncircumcised boys and to evaluate the effect of circumcision on alteration of periurethral uropathogenic bacterial flora. Materials and Methods: Pattern of periurethral bacterial flora before and after circumcision was studied prospectively in 124 boys. The results were analysed to compare change in bacterial colonisation before and after circumcision. Results: The age range was 6 weeks to 96 months. Most (94.3% of the boys had religious indication and 5.7% had medical indication for circumcision. E. coli, Proteus and Klebsiella were most common periurethral bacterial flora in uncircumcised subjects. Coagulase-negative staphylococcus and Staphylococcus aureus was most common periurethral bacterial flora in circumcised subjects. In 66.1% of circumcised subjects, no bacteria were grown from periurethral region. Conclusion: We conclude that presence of prepuce is associated with great quantity of periurethral bacteria, greater likelihood of the presence of high concentration of uropathogens and high incidence of urinary tract infection (UTI. This study provides circumstantial evidence supporting the idea that early circumcision may be beneficial for prevention of UTI.
Newton C.M. Gomes; Cleary, Daniel F. R.; Pinto, Fernando N.; Egas, Conceição; Almeida, Adelaide; Cunha, Angela; Mendonça-Hagler, Leda C. S.; Smalla, Kornelia
Background Mangrove forests are of global ecological and economic importance, but are also one of the world's most threatened ecosystems. Here we present a case study examining the influence of the rhizosphere on the structural composition and diversity of mangrove bacterial communities and the implications for mangrove reforestation approaches using nursery-raised plants. Methodology/Principal Findings A barcoded pyrosequencing approach was used to assess bacterial diversity in the rhizosphe...
Belyansky, L S; Sayenko, V F; Furmanov, J A; Churilova, T J
Failure of intestinal barrier function and subsequent translocation of microorganisms and their degradation products play a decisive role in development of systemic septic complications for many systemic and intra-abdominal pathologies, for example, following obstructive colonic ileus (OCI). This study was aimed at the evaluation of the intestinal barrier state in OCI. Sixty albino Wistar rats weighting 250 to 300 g (mean 265 g) were divided into four groups (15 animals in each). Acute colonic ileus (ACI) was modeled as follows except a control group (Group 1). Our objective was to examine changes in bacterial flora in the abdomen, mesenteric lymphatic nodes (MLN), liver, spleen, and lungs during the model of OCI after 72 hours following the beginning of experiment. The composition of parietal mucus in normal and in OCI 48 hours following the beginning of experiment examined. Interleukin (IL-VI) levels were determined in both portal and peripheral blood. The right-hand half of colon was ligated at the level of ileocaecal junction in animals of Group 2 (n = 15), whereas in animals of Group 3 (n = 15) it was ligated at the level of sigmoid colon. With the same purpose, a portion of the suspended caecal content was administered into lumen of the jejunum at a concentration of 10(6) colony-forming units (CFU) in animals of Group 4 (n = 15). Experimentally--induced OCI causes significant bacterial translocation (BT) in rats. The process of colonization of the proximal small intestine with colonic flora takes place under the conditions of ileus. The conditions favorable for the development of BT are generated with colonization of 10(6) CFU in volume. As a result, intestinal flora penetrates into the abdominal organs and lungs. Its highest concentrations are noted in the lymph nodes, lungs and liver. The modeling of the small intestine colonization with colonic flora (Group 4) demonstrates critical parameters of microbial semination. PMID:12051094
Full Text Available Introduction. Bacterial colonization of catheter tips is common in regional anesthesia and is a suspected risk factor for infectious complications. This is the first study evaluating the effect of CHG-impregnated dressings on bacterial colonization of regional anesthesia catheters in a routine clinical setting. Methods. In this prospective study, regional anesthesia catheter infection rates were examined in two groups of patients with epidural and peripheral regional catheters. In the first group, regional anesthesia was dressed with a conventional draping. The second group of patients underwent catheter dressing using a CHG-impregnated draping. Removed catheters and the insertion sites were both screened for bacterial colonization. Results. A total of 337 catheters from 308 patients were analysed. There was no significant reduction of local infections in either epidural or peripheral regional anesthesia catheters in both CHG and conventional groups. In the conventional group, 21% of the catheter tips and 41% of the insertion sites showed positive culture results. In the CHG-group, however, only 3% of the catheter tips and 8% of the insertion sites were colonised. Conclusion. CHG dressings significantly reduce bacterial colonization of the tip and the insertion site of epidural and peripheral regional catheters. However, no reductions in rates of local infections were seen.
Full Text Available Abstract Background Periodontitis is a chronic inflammatory disease caused by the microbiota of the periodontal pocket. We investigated the association between subgingival bacterial profiles and gene expression patterns in gingival tissues of patients with periodontitis. A total of 120 patients undergoing periodontal surgery contributed with a minimum of two interproximal gingival papillae (range 2-4 from a maxillary posterior region. Prior to tissue harvesting, subgingival plaque samples were collected from the mesial and distal aspects of each tissue sample. Gingival tissue RNA was extracted, reverse-transcribed, labeled, and hybridized with whole-genome microarrays (310 in total. Plaque samples were analyzed using checkerboard DNA-DNA hybridizations with respect to 11 bacterial species. Random effects linear regression models considered bacterial levels as exposure and expression profiles as outcome variables. Gene Ontology analyses summarized the expression patterns into biologically relevant categories. Results Wide inter-species variation was noted in the number of differentially expressed gingival tissue genes according to subgingival bacterial levels: Using a Bonferroni correction (p -7, 9,392 probe sets were differentially associated with levels of Tannerella forsythia, 8,537 with Porphyromonas gingivalis, 6,460 with Aggregatibacter actinomycetemcomitans, 506 with Eikenella corrodens and only 8 with Actinomyces naeslundii. Cluster analysis identified commonalities and differences among tissue gene expression patterns differentially regulated according to bacterial levels. Conclusion Our findings suggest that the microbial content of the periodontal pocket is a determinant of gene expression in the gingival tissues and provide new insights into the differential ability of periodontal species to elicit a local host response.
Full text: Radiotherapy (RTh) for prostatic cancer (CaP) frequently causes radiation proctitis with symptoms of diarrhoea, urgency and faecal incontinence. The contribution of altered colonic transit to these symptoms is not known. Colonic transit was therefore measured by scintigraphy following 4MBq oral 67Ga-citrate in 10 patients (56-81yr) undergoing RTh for CaP. Patients were studied 2 weeks before and at 1 and 12 months after RTh (dose 55-66Gy). Anterior and posterior abdominal scans were performed at 6, 24, 48 and 72 hours. Regions of interest and a composite image of the colon were derived and regional retention in the right and left colon and rectosigmoid region, colonic half clearance times and mean activity profiles determined using geometric mean data. Symptom severity was assessed using a validated questionnaire. There was an increase in stool frequency, faecal incontinence and urgency at 1 and 12 months post RTh (p<0.05). Although there was no difference in overall T1/2 there was reduced retention of tracer in the left colon (L) and rectosigmoid (R/S) region at 1 month with increased tracer retention in the right colon (R) at 1 and 12 months (p<0.05). Regional disturbances in colonic transit are seen in symptomatic patients post RTh for CaP that may contribute to acute symptoms with compensatory changes in the right colon. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc
Sessile bacteria adhere to engineered surfaces and host tissues and pose a substantial clinical and economical risk when growing into biofilms. Most engineered and biological interfaces are of chemically heterogeneous nature and provide adhesive islands for bacterial attachment and growth. To mimic either defects in a surface coating of biomedical implants or heterogeneities within mucosal layers (Peyer's patches), we embedded micrometre-sized adhesive islands in a poly(ethylene glycol) biopassive background. We show experimentally and computationally that filamentation of Escherichia coli can significantly accelerate the bacterial surface colonization under physiological flow conditions. Filamentation can thus provide an advantage to a bacterial population to bridge non-adhesive distances exceeding 5 μm. Bacterial filamentation, caused by blocking of bacterial division, is common among bacterial species and can be triggered by environmental conditions or antibiotic treatment. While great awareness exists that the build-up of antibiotic resistance serves as intrinsic survival strategy, we show here that antibiotic treatment can actually promote surface colonization by triggering filamentation, which in turn prevents daughter cells from being washed away. Our combined microfabrication and computational approaches provide quantitative insights into mechanisms that enable biofouling of biopassive surfaces with embedded adhesive spots, even for spot distances that are multiples of the bacterial length. (paper)
AIM: To investigate the prognostic value of chromosome 18q microsatellite alterations (MA) in stage Ⅱ colon cancer. METHODS: One hundred and six patients with sporadic stage Ⅱ colon cancer were enrolled in this study. DNA was extracted from formalin-fixed, paraffin-embedded tumor and adjacent normal mucosal tissue samples. MA, including loss of heterozygosity (LOH) and microsatellite instability (MSI), was analyzed by polymerase chain reaction, polyacrylamide gel-electrophoresis and DNA sequencing at 5 micr...
The primary anions of the colon are short-chain fatty acids (SCFA) produced by intestinal microorganisms from endogenous secretions and dietary fiber. The effects of the SCFA propionate on ion transport by the epithelium of rabbit distal colon were studied on tissues stripped of underlying musculature and mounted in Ussing chambers. When tissues were bathed with NaCl Ringer's solutions at 370C (5% CO2-21mM HCO3, pH 7.4) replacement of 33mM Cl- in both tissue baths by propionate reduced short-circuit current (Isc) from 86 to 35 μA/cm2 and increased transepithelial conductance (G/sub t/) from 3.6 to 5.6mS/cm2. Unidirectional 14C-propionate flux measurements revealed that this ion was secreted at a rate of 0.5μEq/cm2hr. Intracellular measurements with potential and pH sensitive microelectrodes showed that propionate reduced intracellular pH (PH/sub i/) from 6.84 to 6.68 (P 2, decreased G/sub t/ to 5.3mS/cm2, hyperpolarized phi/sub a/ by 5mV (P + secretion
Philip J Hill
Full Text Available BACKGROUND: Recent studies have shown that human ferritin can be used as a reporter of gene expression for magnetic resonance imaging (MRI. Bacteria also encode three classes of ferritin-type molecules with iron accumulation properties. METHODS AND FINDINGS: Here, we investigated whether these bacterial ferritins can also be used as MRI reporter genes and which of the bacterial ferritins is the most suitable reporter. Bacterial ferritins were overexpressed in probiotic E. coli Nissle 1917. Cultures of these bacteria were analyzed and those generating highest MRI contrast were further investigated in tumor bearing mice. Among members of three classes of bacterial ferritin tested, bacterioferritin showed the most promise as a reporter gene. Although all three proteins accumulated similar amounts of iron when overexpressed individually, bacterioferritin showed the highest contrast change. By site-directed mutagenesis we also show that the heme iron, a unique part of the bacterioferritin molecule, is not critical for MRI contrast change. Tumor-specific induction of bacterioferritin-expression in colonized tumors resulted in contrast changes within the bacteria-colonized tumors. CONCLUSIONS: Our data suggest that colonization and gene expression by live vectors expressing bacterioferritin can be monitored by MRI due to contrast changes.
Horvath, P.J.; Weiser, M.M.; Duffey, M.E.
The primary anions of the colon are short-chain fatty acids (SCFA) produced by intestinal microorganisms from endogenous secretions and dietary fiber. The effects of the SCFA propionate on ion transport by the epithelium of rabbit distal colon were studied on tissues stripped of underlying musculature and mounted in Ussing chambers. When tissues were bathed with NaCl Ringer's solutions at 37/sup 0/C (5% CO/sub 2/-21mM HCO/sub 3/, pH 7.4) replacement of 33mM Cl/sup -/ in both tissue baths by propionate reduced short-circuit current (Isc) from 86 to 35 ..mu..A/cm/sup 2/ and increased transepithelial conductance (G/sub t/) from 3.6 to 5.6mS/cm/sup 2/. Unidirectional /sup 14/C-propionate flux measurements revealed that this ion was secreted at a rate of 0.5..mu..Eq/cm/sup 2/hr. Intracellular measurements with potential and pH sensitive microelectrodes showed that propionate reduced intracellular pH (PH/sub i/) from 6.84 to 6.68 (P < 0.02), depolarized the apical membrane potential (phi/sub a/) by 4mV (P < 0.02) and decreased the membrane fractional resistance (f/sub R/) from .78 to .71 (P < 0.001). Addition of 0.1mM amiloride to the mucosal bath reversed Isc to -18..mu..A/cm/sup 2/, decreased G/sub t/ to 5.3mS/cm/sup 2/, hyperpolarized phi/sub a/ by 5mV (P < 0.05) and increased f/sub R/ to 0.85 (P < 0.001). Amiloride had no effect on pH/sub i/. These results show that propionate can be secreted by rabbit distal colon and that exposure to this SCFA causes cell acidification and electrophysiological changes consistent with H/sup +/ secretion.
Gilsdorf, J R; Wilson, K; Beals, T F
Four different intravenous catheter materials, brands Teflon, Silastic, Vialon, and Tecoflex, were evaluated in vitro for bacterial adherence after 2 and 24 hours' incubation in trypticase soy broth and after 2 hours' incubation in nutrient-free phosphate buffer (pH 7.2). The organisms used were Pseudomonas aeruginosa, Enterobacter aerogenes, Escherichia coli, and Staphylococcus epidermidis. The significant differences in in vitro adherence of the different bacterial species to the various catheters were then evaluated in vivo by intravenous injection of a single bolus of 1 X 10(5) organisms via tail vein of rats with previously placed catheters in their superior venae cavae. There was no association between the in vitro bacterial adherence and the tendency of the in vivo catheters to become colonized. Results of scanning electron microscopy of clean catheters and those removed from the rats showed obvious differences in surface characteristics and in clot adhesion between the catheters. These characteristics did not correlate with bacterial adherence in vitro or colonization in vivo. It is concluded that laboratory studies of bacterial adherence to, physical characteristics of, and thrombogenicity of intravenous catheters do not necessarily translate into resistance to clinical catheter sepsis. PMID:2500724
CHEN Yu-Qing; REN Guan-Ju; AN Shu-Qing; SUN Qing-Ye; LIU Chang-Hong; SHUANG Jing-Lei
Soil samples were collected from both bare and vegetated mine tailings to study the changes in bacterial communities and soil chemical properties of copper mine tailings due to reed (Phragmites communis) colonization. The structures of bacterial communities were investigated using culture-independent 16S rRNA gene sequencing method. The bacterial diversity in the bare mine tailing was lower than that of the vegetated mine tailing. The former was dominated by sulfur metabolizing bacteria, whereas the latter was by nitrogen fixing bacteria. The bare mine tailing was acidic (pH = 3.78), whereas the vegetated mine tailing was near neutral (pH = 7.28). The contents of organic matter, total nitrogen, and ammonium acetate-extractable otassium in vegetated mine tailings were significantly higher than those in the bare mine tailings (P < 0.01), whereas available phosphorus and electrical conductivity were significantly lower than those in the bare mine tailings (P < 0.01). The results demonstrated that 16S rRNA gene sequencing could be successfully used to study the bacterial diversity in mine tailings. The colonization of the mine tailings by reed significantly changed the bacterial community and the chemical properties of tailings. The complex interactions between bacteria and plants deserve further investigation.
Shelley, W B; Zolin, W D
A patient with acute lymphoblastic leukemia suddenly developed a disseminated monomorphic eruption of purpuric papules. The papules were initially thought to be lesions of vasculitis, leukemia cutis, or septic emboli. Histologic study, however, revealed large focal colonies of gram-positive cocci within the dermis. It is postulated that a bacteremia of antibiotic-resistant cocci led to dissemination of these organisms into a virtually defenseless skin. The patient's pancytopenia and consequent immune paralysis are viewed as accounting for this focal bacterial colonization and for the remarkable absence of clinical and histologic inflammatory response. Such hematogenous noninflammatory bacterial colonization of the skin must be added to the differential diagnosis of palpable purpura. PMID:6575017
Zhong, Yu; Anderl, Florian; Kruse, Tobias; Schindele, Franziska; Jagusztyn-Krynicka, Elżbieta Katarzyna; Fischer, Wolfgang; Gerhard, Markus
The Dsb protein family is responsible for introducing disulfide bonds into nascent proteins in prokaryotes, stabilizing the structure of many proteins. Helicobacter pylori HP0231 is a Dsb-like protein, shown to catalyze disulfide bond formation and to participate in redox homeostasis. Notably, many H. pylori virulence factors are stabilized by the formation of disulfide bonds. By employing H. pylori HP0231 deficient strains we analyzed the effect of lack of this bacterial protein on the functionality of virulence factors containing putative disulfide bonds. The lack of H. pylori HP0231 impaired CagA translocation into gastric epithelial cells and reduced VacA-induced cellular vacuolation. Moreover, H. pylori HP0231 deficient bacteria were not able to colonize the gastric mucosa of mice, probably due to compromised motility. Together, our data demonstrate an essential function for H. pylori HP0231 in gastric colonization and proper function of bacterial virulence factors related to gastric pathology. PMID:27138472
Vikram, Amit; Lipus, Daniel; Bibby, Kyle
Microbial activity during the holding and reuse of wastewater from hydraulic fracturing operations, termed produced water, may lead to issues with corrosion, sulfide release, and fouling. Biocides are applied to control biological activity, often with limited efficacy, which is typically attributed to chemical interactions with the produced water. However, it is unknown whether there is a biologically driven mechanism to biocide tolerance in produced water. Here, we demonstrate that produced water exposure results in an enhanced tolerance against the typically used biocide glutaraldehyde and increased susceptibility to the oxidative biocide hypochlorite in a native and a model bacteria and that this altered resistance is due to the salinity of the produced water. In addition, we elucidate the genetic response of the model organism Pseudomonas fluorescens to produced water exposure to provide a mechanistic interpretation of the altered biocide resistance. The RNA-seq data demonstrated the induction of genes involved in osmotic stress, energy production and conversion, membrane integrity, and protein transport following produced water exposure, which facilitates bacterial survival and alters biocide tolerance. Efforts to fundamentally understand biocide resistance mechanisms, which enable the optimization of biocide application, hold significant implications for greening of the fracturing process through encouraging produced water recycling. Specifically, these results suggest the necessity of optimizing biocide application at the level of individual shale plays, rather than historical experience, based upon produced water characteristics and salinity. PMID:25279933
Remus-Emsermann, Mitja N P; Tecon, Robin; Kowalchuk, George A.; Leveau, Johan H. J.
Using a phyllosphere model system, we demonstrated that the term ‘carrying capacity', as it is commonly used in microbial ecology, needs to be understood as the sum of many ‘local carrying capacities' in order to better explain and predict the course and outcome of bacterial colonization of an environment. Using a green fluorescent protein-based bioreporter system for the quantification of reproductive success (RS) in individual Erwinia herbicola cells, we were able to reconstruct the contrib...
Tese de doutoramento em Engenharia Química e Biológica (ramo de conhecimento em Tecnologia Microbiana) Biomedical devices are susceptible of microbial contamination. Adhering bacteria to contact lenses (CLs) may induce ocular infections, being microbial keratitis (MK) the most sight threatening. The present Thesis investigates the role of surface properties and conditioning film on microbial colonization, bacterial adhesion, detachment, viability and disinfection of silicone hy...
Chateauvert, Christopher Adam
Concentrations, distributions, and bacterial colonization of transparent exopolymer particles (TEP) were tracked from June through August 2006 among three lakes of varying flooding frequency, in the Mackenzie Delta. Microscopic image analysis showed spectrophotometric methods generally over-estimated TEP concentrations in this system. TEP concentrations were highest immediately after river flooding and declined through August. Contrary to expectation, TEP concentrations were highest in the hi...
Park, A J; Collins, J.; BLENNERHASSETT, P. A.; Ghia, J E; Verdu, E. F.; Bercik, P; COLLINS, S. M.
Background Depression often coexists with the irritable bowel syndrome (IBS) which is characterized by alterations in gut function. There is emerging evidence that the microbial composition (microbiota) of the gut is altered in IBS, but the basis for this is poorly understood. The aim of this study was to determine whether the induction of chronic depression results in changes in the colonic function and in its microbial community, and to explore underlying mechanisms. Methods Bilateral olfac...
Stacey D Gilk
Full Text Available Reports implicating important roles for cholesterol and cholesterol-rich lipid rafts in host-pathogen interactions have largely employed sterol sequestering agents and biosynthesis inhibitors. Because the pleiotropic effects of these compounds can complicate experimental interpretation, we developed a new model system to investigate cholesterol requirements in pathogen infection utilizing DHCR24(-/- mouse embryonic fibroblasts (MEFs. DHCR24(-/- MEFs lack the Δ24 sterol reductase required for the final enzymatic step in cholesterol biosynthesis, and consequently accumulate desmosterol into cellular membranes. Defective lipid raft function by DHCR24(-/- MEFs adapted to growth in cholesterol-free medium was confirmed by showing deficient uptake of cholera-toxin B and impaired signaling by epidermal growth factor. Infection in the absence of cholesterol was then investigated for three intracellular bacterial pathogens: Coxiella burnetii, Salmonella enterica serovar Typhimurium, and Chlamydia trachomatis. Invasion by S. Typhimurium and C. trachomatis was unaltered in DHCR24(-/- MEFs. In contrast, C. burnetii entry was significantly decreased in -cholesterol MEFs, and also in +cholesterol MEFs when lipid raft-associated α(Vβ(3 integrin was blocked, suggesting a role for lipid rafts in C. burnetii uptake. Once internalized, all three pathogens established their respective vacuolar niches and replicated normally. However, the C. burnetii-occupied vacuole within DHCR24(-/- MEFs lacked the CD63-positive material and multilamellar membranes typical of vacuoles formed in wild type cells, indicating cholesterol functions in trafficking of multivesicular bodies to the pathogen vacuole. These data demonstrate that cholesterol is not essential for invasion and intracellular replication by S. Typhimurium and C. trachomatis, but plays a role in C. burnetii-host cell interactions.
Remus-Emsermann, Mitja N P; Tecon, Robin; Kowalchuk, George A; Leveau, Johan H J
Using a phyllosphere model system, we demonstrated that the term 'carrying capacity', as it is commonly used in microbial ecology, needs to be understood as the sum of many 'local carrying capacities' in order to better explain and predict the course and outcome of bacterial colonization of an environment. Using a green fluorescent protein-based bioreporter system for the quantification of reproductive success (RS) in individual Erwinia herbicola cells, we were able to reconstruct the contribution of individual immigrants to bacterial population sizes on leaves. Our analysis revealed that plant foliage represents to bacteria an environment where individual fate is determined by the local carrying capacity of the site where an immigrant cell lands. With increasing inoculation densities, the RS of most immigrants declined, suggesting that local carrying capacity under the tested conditions was linked to local nutrient availability. Fitting the observed experimental data to an adapted model of phyllosphere colonization indicated that there might exist three types of sites on leaves, which differ in their frequency of occurrence and local carrying capacity. Specifically, our data were consistent with a leaf environment that is characterized by few sites where individual immigrants can produce high numbers of offspring, whereas the remainder of the leaf offered an equal number of sites with low and medium RS. Our findings contribute to a bottom-up understanding of bacterial colonization of leaf surfaces, which includes a quantifiable role of chance in the experience at the individual level and in the outcome at the population level. PMID:22258099
Cassir, N; Papazian, L; Fournier, P-E; Raoult, D; La Scola, B
Skin is a major reservoir of bacterial pathogens in intensive care unit (ICU) patients. The aim of this study was to assess the skin bacterial richness and diversity in ICU patients and the effect of CHG daily bathing on skin microbiota. Twenty ICU patients were included during an interventional period with CHG daily bathing (n = 10) and a control period (n = 10). At day seven of hospitalization, eight skin swab samples (nares, axillary vaults, inguinal creases, manubrium and back) were taken from each patient. The bacterial identification was performed by microbial culturomics. We used the Shannon index to compare the diversity. We obtained 5,000 colonies that yielded 61 bacterial species (9.15 ± 3.7 per patient), including 15 (24.5 %) that had never been cultured from non-pathological human skin before, and three (4.9 %) that had never been cultured from human samples before. Notably, Gram-negative bacteria were isolated from all sites. In the water-and-soap group, there was a higher risk of colonization with Gram-negative bacteria (OR = 6.05, 95 % CI [1.67-21.90]; P = 0.006). In the CHG group, we observed more patients colonized by sporulating bacteria (9/10 vs. 3/10; P = 0.019) with a reduced skin bacterial richness (P = 0.004) and lower diversity (0.37, 95 % CI [0.33; 0.42] vs. 0.50, 95 % CI [0.48; 0.52]). Gram-negative bacteria are frequent and disseminated components of the transient skin flora in ICU patients. CHG daily bathing is associated with a reduction in Gram-negative bacteria colonization together with substantial skin microbiota shifts. PMID:25604707
Schiffrin, E J; Carter, E A; Walker, W A; Frieberg, E; Benjamin, J; Israel, E J
The interactions between bacteria and the host's intestinal barrier appear to be important regulators of bacterial colonization. In this study we investigated the effect of prenatal corticosteroids, known to accelerate the intestinal maturation of newborn rats, on bacterial colonization in the rat pup. Pregnant rats were treated with either cortisone acetate or normal saline on days 18-21 of gestation and were allowed to deliver spontaneously. The pups, after normal delivery, were sacrificed at different times during the first 10 days of life. The entire small intestine was removed, and each lumen was flushed to exclude nonadherent, transient organisms and homogenized. Tenfold dilutions were plated on horse-blood agar (total bacteria) and MacConkey's medium (gram-negatives). Quantitation and bacterial typification was determined after 24 h of incubation at 37 degrees C. Total bacteria and gram-negatives found in association with the mucosa were significantly lower in pups prenatally treated with steroids. These changes were not related to any changes in motility or intraluminal digestion. This suggests that the developmental condition of the host's intestinal barrier may be an important regulator of the bacterial microenvironment of the newborn small intestinal mucosa. PMID:8271126
Satya Prakash; Aleksandra Malgorzata Urbanska
Satya Prakash, Aleksandra Malgorzata UrbanskaBiomedical Technology and Cell Therapy Research Laboratory, Departments of Biomedical Engineering and Physiology, Artificial Cells and Organs Research Center, Faculty of Medicine, McGill University, Montreal, Quebec, CanadaAbstract: There has been an ample interest in delivery of therapeutic molecules using live cells. Oral delivery has been stipulated as best way to deliver live cells to humans for therapy. Colon, in particular, is a part of gastr...
Portillo, M Carmen; Saiz-Jimenez, Cesareo; Gonzalez, Juan M
Caves with paleolithic paintings are influenced by bacterial development. Altamira Cave (Spain) contains some of the most famous paintings from the Paleolithic era. An assessment of the composition of bacterial communities that have colonized this cave represents a first step in understanding and potentially controlling their proliferation. In this study, areas showing colonization with uncolored microorganisms, referred to as "white colonizations", were analyzed. Microorganisms present in these colonizations were studied using DNA analysis, and those showing significant metabolic activity were detected in RNA-based RNA analysis. Bacterial community fingerprints were obtained both from DNA and RNA analyses, indicating differences between the microorganisms present and metabolically active in these white colonizations. Metabolically active microorganisms represented only a fraction of the total bacterial community present in the colonizations. 16S rRNA gene libraries were used to identify the major representative members of the studied communities. Proteobacteria constituted the most frequently found division both among metabolically active microorganisms (from RNA-based analysis) and those present in the community (from DNA analysis). Results suggest the existence of a huge variety of taxa in white colonizations of the Altamira Cave which represent a potential risk for the conservation of the cave and its paintings. PMID:18984039
Full Text Available Kristina Andelid,1 Sara Tengvall,1 Anders Andersson,1 Bettina Levänen,2 Karin Christenson,3 Pernilla Jirholt,3 Christina Åhrén,4 Ingemar Qvarfordt,1 Ann Ekberg-Jansson,1 Anders Lindén2 1Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; 2Unit of Lung and Airway Research, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; 3Department of Rheumatology and Inflammation Research, Institute of Medicine, 4Department of Infectious Diseases, Infection Control Unit, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden Abstract: We examined whether systemic cytokine signaling via interleukin (IL-17 and growth-related oncogene-α (GRO-α is impaired in smokers with obstructive pulmonary disease including chronic bronchitis (OPD-CB. We also examined how this systemic cytokine signaling relates to bacterial colonization in the airways of the smokers with OPD-CB. Currently smoking OPD-CB patients (n=60, corresponding to Global initiative for chronic Obstructive Lung Disease [GOLD] stage I–IV underwent recurrent blood and sputum sampling over 60 weeks, during stable conditions and at exacerbations. We characterized cytokine protein concentrations in blood and bacterial growth in sputum. Asymptomatic smokers (n=10 and never-smokers (n=10 were included as control groups. During stable clinical conditions, the protein concentrations of IL-17 and GRO-α were markedly lower among OPD-CB patients compared with never-smoker controls, whereas the asymptomatic smoker controls displayed intermediate concentrations. Notably, among OPD-CB patients, colonization by opportunistic pathogens was associated with markedly lower IL-17 and GRO-α, compared with colonization by common respiratory pathogens or oropharyngeal flora. During exacerbations in the OPD-CB patients, GRO-α and neutrophil
Christianson, Julie A; Bielefeldt, Klaus; Malin, Sacha A; Davis, Brian M
Inflammation or pain during neonatal development can result in long-term structural and functional alterations of nociceptive pathways, ultimately altering pain perception in adulthood. We have developed a mouse model of neonatal colon irritation (NCI) to investigate the plasticity of pain processing within the viscerosensory system. Mouse pups received an intracolonic administration of 2% mustard oil (MO) on postnatal days 8 and 10. Distal colons were processed at subsequent timepoints for myeloperoxidase (MPO) activity and growth factor expression. Adult mice were assessed for visceral hypersensitivity by measuring the visceromotor response during colorectal distension. Dorsal root ganglion (DRG) neurons from adult mice were retrogradely labeled from the distal colon and calcium imaging was used to measure transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) responses to acute application of capsaicin and MO, respectively. Despite the absence of inflammation (as indicated by MPO activity), neonatal exposure to intracolonic MO transiently maintained a higher expression level of growth factor messenger RNA (mRNA). Adult NCI mice displayed significant visceral hypersensitivity, as well as increased sensitivity to mechanical stimulation of the hindpaw, compared to control mice. The percentage of TRPA1-expressing colon afferents was significantly increased in NCI mice, however they displayed no increase in the percentage of TRPV1-immunopositive or capsaicin-sensitive colon DRG neurons. These results suggest that early neonatal colon injury results in a long-lasting visceral hypersensitivity, possibly driven by an early increase in growth factor expression and maintained by permanent changes in TRPA1 function. PMID:20850221
Halil Coskun; Suleyman Bozkurt
Intragastric balloon therapy, as a part of a multidisciplinary weight management program, is an effective short-term intervention for weight loss. Although the insertion procedure is easy and generally well tolerated by patients, a few complications can occur. We report here a heavy smoker with intragastric balloon insertion complicated by colonization with opportunistic organisms. The 27-year-old female, body mass index 35.5 kg/m2, had a BioEnterics. Intragastric Balloon inserted under conscious sedation without any perioperative complications. Six months later, when the standard removal time arrived, the balloon was seen to be covered with a necrotic white-gray material. Microbiological examination revealed Enterobacter cloacae and Candida species yeast colonies. We recommend that asymptomatic fungal and/or bacterial colonization should be considered among the complications of the intragastric balloon procedure, despite its rarity.
Full Text Available Bacterial colonization of biotic or abiotic surfaces results from two quite distinct physiological processes, namely bacterial adhesion and biofilm formation. Broadly speaking, a biofilm is defined as the sessile development of microbial cells. Biofilm formation arises following bacterial adhesion but not all single bacterial cells adhering reversibly or irreversibly engage inexorably into a sessile mode of growth. Among molecular determinants promoting bacterial colonization, surface proteins are the most functionally diverse active components. To be present on the bacterial cell surface, though, a protein must be secreted in the first place. Considering the close association of secreted proteins with their cognate secretion systems, the secretome (which refers both to the secretion systems and their protein substrates is a key concept to apprehend the protein secretion and related physiological functions. The protein secretion systems are here considered in light of the differences in the cell-envelope architecture between diderm-LPS (archetypal Gram-negative, monoderm (archetypal Gram-positive and diderm-mycolate (archetypal acid-fast bacteria. Besides, their cognate secreted proteins engaged in the bacterial colonization process are regarded from single protein to supramolecular protein structure as well as the non-classical protein secretion. This state-of-the-art on the complement of the secretome (the secretion systems and their cognate effectors involved in the surface colonization process in diderm-LPS and monoderm bacteria paves the way for future research directions in the field.
Addressing fouling and more particularly biofouling phenomena occurring notably on structures in marine environment, this research thesis first describes the fouling phenomenon (components, sequences of biofouling development, bio-film chemical composition). The author reports the study of the composition of the biological veil (microbiological methods, presentation of the different components), addresses the various types of lipids (bacterial markers and others). Then, after a presentation of the experimental equipment and methods (test cells, sample preparation, gas phase chromatography, hydrogenation and bromination, mass spectrometry), the author discusses the influence of different parameters such as the substrate type, speed, season, chlorination, and correlation with thermal transfer
Post-transcriptional regulation of gene expression by microRNA (miRNA) has recently attracted major interest in relation to its involvement in cancer development. miRNA is a member of small non-coding RNA, consists of 22-24 nucleotides and regulates expression of target mRNA species in a post-transcriptional manner by being incorporated with RNA-induced silencing complex (RISC). Staphylococcal nuclease homology domain containing 1 (SND1), a component of RISC, is frequently up-regulated in human colon cancers and also chemically induced colon cancers in animals. We here showed that SDN1 is involved in miRNA-mediated gene suppression and overexpression of SND1 in colon cancer cells causes down-regulation of APC without altering APC mRNA levels. As for the miRNA expression profile in human colon cancer, miR-34a was among the list of down-regulated miRNA. Expression of miR-34a is tightly regulated by p53, and ectopic expression of miR-34a in colon cancer cells causes remarkable reduction of cell proliferation and induces senescence-like phenotypes. MiR-34a also participates in the positive feedback loop of the p53 tumor suppressor network. This circuitry mechanism for p53 activation is of interest in understanding the tumor suppressive function of miR-34a in colon carcinogenesis. miRNA should also be considered as novel anti-cancer agents in tumor suppressive therapeutic applications.
Al-Ahmad, Ali; Follo, Marie; Selzer, Ann-Carina; Hellwig, Elmar; Hannig, Matthias; Hannig, Christian
Oral biofilms are one of the greatest challenges in dental research. The present study aimed to investigate initial bacterial colonization of enamel surfaces in situ using fluorescence in situ hybridization (FISH) over a 12 h period. For this purpose, bovine enamel slabs were fixed on buccal sites of individual splints worn by six subjects for 2, 6 and 12 h to allow biofilm formation. Specimens were processed for FISH and evaluated with confocal laser-scanning microscopy, using probes for eubacteria, Streptococcus species, Veillonella species, Fusobacterium nucleatum and Actinomyces naeslundii. The number of adherent bacteria increased with time and all tested bacterial species were detected in the biofilm formed in situ. The general percentage composition of the eubacteria did not change over the investigated period, but the number of streptococci, the most frequently detected species, increased significantly with time (2 h: 17.7+/-13.8 %; 6 h: 20.0+/-16.6 %; 12 h: 24.7+/-16.1 %). However, < or =1 % of the surface was covered with bacteria after 12 h of biofilm formation in situ. In conclusion, FISH is an appropriate method for quantifying initial biofilm formation in situ, and the proportion of streptococci increases during the first 12 h of bacterial adherence. PMID:19528150
Bergström Anders; Kristensen Matilde B; Bahl Martin I; Metzdorff Stine B; Fink Lisbeth N; Frøkiær Hanne; Licht Tine R
Abstract Background Postnatal regulation of the small intestinal mucus layer is potentially important in the development of adult gut functionality. We hypothesized that the nature of bacterial colonization affects mucus gene regulation in early life. We thus analyzed the influence of the presence of a conventional microbiota as well as two selected monocolonizing bacterial strains on the transcription of murine genes involved in mucus layer development during the first week of life. Mouse pu...
Mari, X.; Kiørboe, Thomas
The abundance, size distribution and bacterial colonization of transparent exopolymeric particles (TEP) were monitored in the Kattegat (Denmark) at weekly intervals throughout the spring (February-May) encompassing the spring diatom bloom. These recently discovered particles are believed to be...... formed from colloidal organic material exuded by phytoplankton and bacteria, and may have significant implications for pelagic flux processes. During this study, the number concentration of TEP (>1 mu m) ranged from 3 x 10(3) to 6 x 10(4) ml(-1) and the volume concentration between 0.3 and 9.0 p.......p.m.; they were most abundant in the surface waters subsequent to the spring phytoplankton bloom. The range of TEP (encased) volume concentration was similar to that of the phytoplankton, although at times TEP volume concentration exceeded that of the phytoplankton by two orders of magnitude. The TEP size...
Mahoney, Eric; Reichner, Jonathan; Robinson Bostom, Leslie; Mastrofrancesco, Balduino; Henry, William; Albina, Jorge
The expression of inducible nitric oxide synthase (iNOS) in two different murine wound models was investigated. Animals were subjected to either full-thickness linear skin incision with subcutaneous implantation of sterile polyvinyl alcohol sponges, or to 1.5 × 1.5-cm dorsal skin excision. Reverse transcriptase-polymerase chain reaction detected iNOS mRNA in all cell samples retrieved from the sponges. Immunoblotting of lysates of inflammatory cells harvested from the sponges failed to detect iNOS protein, and immunohistochemistry of the incisional wound was mildly positive. Inflammatory cells of excisional wounds stained strongly positive for iNOS. Cutaneous wounds were found to be colonized with Staphylococcus aureus. The detection of iNOS in cells from sponges inoculated in vivo with heat-killed bacteria and the reduction of immunohistochemical signal for iNOS in excisional wounds of animals treated with antibiotics support a role of bacteria in the induction of iNOS in wounds. The expression of iNOS in excisional wounds requires interferon-γ and functional lymphocytes because interferon-γ knockout and SCID-Beige mice exhibited attenuated iNOS staining in excisional wounds. The expression of iNOS in the inflammatory cells of murine wounds is a response to bacterial colonization and not part of the normal repair process elicited by sterile tissue injury. PMID:12466130
Ott, S.J.; Musfeldt, M; Wenderoth, D F; Hampe, J; Brant, O; Fölsch, U R; Timmis, K N; Schreiber, S
Background and aims: The intestinal bacterial microflora plays an important role in the aetiology of inflammatory bowel disease (IBD). As most of the colonic bacteria cannot be identified by culture techniques, genomic technology can be used for analysis of the composition of the microflora.
Belstrøm, D; Fiehn, N-E; Nielsen, C H;
salivarius) and three bacterial clusters (Streptococcus parasanguinis I and II and sp. clone BE024_ot057/411/721, Streptococcus parasanguinis I and II and sinensis_ot411/721/767, Streptococcus salivarius and sp. clone FO042_ot067/755) were present at significantly higher levels (adjusted p value ..., Megasphaera micronuciformis, Fusobacterium periodontium and Achromobacter xylosoxidans) and one bacterial cluster (Leptotrichia sp. clones C3MKM102 and GT018_ot417/462) were less frequently found in the caries group (adjusted p value Streptococcus...
Wang, Qichen; Uzunoglu, Emel; Wu, Yong; Libera, Matthew
We explored the use of self-assembled microgels to inhibit the bacterial colonization of synthetic surfaces both by modulating surface cell adhesiveness at length scales comparable to bacterial dimensions (∼1 μm) and by locally storing/releasing an antimicrobial. Poly(ethylene glycol) [PEG] and poly(ethylene glycol)-co-acrylic acid [PEG-AA] microgels were synthesized by suspension photopolymerization. Consistent with macroscopic gels, a pH dependence of both zeta potential and hydrodynamic diameter was observed in AA-containing microgels but not in pure PEG microgels. The microgels were electrostatically deposited onto poly(l-lysine) (PLL) primed silicon to form submonolayer surface coatings. The microgel surface density could be controlled via the deposition time and the microgel concentration in the parent suspension. In addition to their intrinsic antifouling properties, after deposition, the microgels could be loaded with a cationic antimicrobial peptide (L5) because of favorable electrostatic interactions. Loading was significantly higher in PEG-AA microgels than in pure PEG microgels. The modification of PLL-primed Si by unloaded PEG-AA microgels reduced the short-term (6 h) S. epidermidis surface colonization by a factor of 2, and the degree of inhibition increased when the average spacing between microgels was reduced. Postdeposition L5 peptide loading into microgels further reduced bacterial colonization to the extent that, after 10 h of S. epidermidis culture in tryptic soy broth, the colonization of L5-loaded PEG-AA microgel-modified Si was comparable to the very small level of colonization observed on macroscopic PEG gel controls. The fact that these microgels can be deposited by a nonline-of-sight self-assembly process and hinder bacterial colonization opens the possibility of modifying the surfaces of topographically complex biomedical devices and reduces the rate of biomaterial-associated infection. PMID:22519439
Strickman, R J S; Fulthorpe, R R; Coleman Wasik, J K; Engstrom, D R; Mitchell, C P J
As part of a long-term, peatland-scale sulfate addition experiment, the impact of varying sulfate deposition on bacterial community responses was assessed using 16S tag encoded pyrosequencing. In three separate areas of the peatland, sulfate manipulations included an eight year quadrupling of atmospheric sulfate deposition (experimental), a 3-year recovery to background deposition following 5years of elevated deposition (recovery), and a control area. Peat concentrations of methylmercury (MeHg), a bioaccumulative neurotoxin, were measured, the production of which is attributable to a growing list of microorganisms, including many sulfate-reducing Deltaproteobacteria. The total bacterial and Deltaproteobacterial community structures in the experimental treatment differed significantly from those in the control and recovery treatments that were either indistinguishable or very similar to one another. Notably, the relatively rapid return (within three years) of bacterial community structure in the recovery treatment to a state similar to the control, demonstrates significant resilience of the peatland bacterial community to changes in atmospheric sulfate deposition. Changes in MeHg accumulation between sulfate treatments correlated with changes in the Deltaproteobacterial community, suggesting that sulfate may affect MeHg production through changes in the community structure of this group. PMID:27267720
Rubio, Alejandro; Boyen, Filip; Tas, Olaf; Kitshoff, Adriaan; Polis, Ingeborgh; Van Goethem, Bart; de Rooster, Hilde
Septic peritonitis occurs relatively commonly in dogs. Secondary septic peritonitis is usually associated with perforation of intestines or infected viscera, such as the uterus in pyometra cases. The aim of this study was to evaluate the bacterial flora in the ovarian bursae of intact bitches as a potential source of contamination. One hundred forty dogs, clinically suspected of pyometra, were prospectively enrolled. The control group consisted of 26 dogs that underwent elective ovariohysterectomies and 18 dogs with mammary gland tumors that were neutered at the time of mastectomy. Bacteriology samples were taken aseptically at the time of surgery from the bursae and the uterus in all dogs. Twenty-two dogs that were clinically suspected of pyometra had sterile uterine content ("mucometra" cases); the remaining 118 had positive uterine cultures ("pyometra" cases) and septic peritoneal fluid was present in 10% of these cases. Of the 118 pyometra cases, 9 had unilateral and 15 had bilateral bacterial colonization of their ovarian bursae. However, the bacteria from the ovarian bursa were similar to those recovered from the uterine pus in only half of the cases. Furthermore, positive bursae were also seen in one mucometra dog (unilateral) and in four control dogs (two unilateral and two bilateral). The data illustrate that the canine ovarian bursa can harbor bacteria. The biological importance of these isolations remains unclear. PMID:25127745
Ximei Zhang; Xingguo Han
Nitrogen deposition has dramatically altered biodiversity and ecosystem functioning on the earth; however,its effects on soil bacterial community and the underlying mechanisms of these effects have not been thoroughly examined.Changes in ecosystems caused by nitrogen deposition have traditionally been attributed to increased nitrogen content.In fact,nitrogen deposition not only leads to increased soil total N content,but also changes in the NH4+-N content,NO3--N content and pH,as well as changes in the heterogeneity of the four indexes.The soil indexes for these four factors,their heterogeneity and even the plant community might be routes through which nitrogen deposition alters the bacterial community.Here,we describe a 6-year nitrogen addition experiment conducted in a typical steppe ecosystem to investigate the ecological mechanism by which nitrogen deposition alters bacterial abundance,diversity and composition.We found that various characteristics of the bacterial community were explained by different environmental factors.Nitrogen deposition decreased bacterial abundance that is positively related to soil pH value.In addition,nitrogen addition decreased bacterial diversity,which is negatively related to soil total N content and positively related to soil NO3--N heterogeneity.Finally,nitrogen.addition altered bacterial composition that is significantly related to soil NH4+-N content.Although nitrogen deposition significantly altered plant biomass,diversity and composition,these characteristics of plant community did not have a significant impact on processes of nitrogen deposition that led to alterations in bacterial abundance,diversity and composition.Therefore,more sensitive molecular technologies should be adopted to detect the subtle shifts of microbial community structure induced by the changes of plant community upon nitrogen deposition.
Hansen, Geir Høvik; Olafsen, Jan A.
Aquaculture has brought about increased interest in mass production of marine fish larvae. Problems such as poor egg quality and mass mortality of fish larvae have been prevalent. The intensive incubation techniques that often result in bacterial overgrowth on fish eggs could affect the commensal relationship between the indigenous microflora and opportunistic pathogens and subsequently hamper egg development, hatching, larval health, and ongrowth. Little information about the adherent microflora on fish eggs is available, and the present study was undertaken to describe the microbial ecology during egg development and hatching of two fish species of potential commercial importance in marine aquaculture. Attachment and development of the bacterial flora on cod (Gadus morhua L.) eggs from fertilization until hatching was studied by scanning electron microscopy. The adherent microflora on cod (G. morhua L.) and halibut (Hippoglossus hippoglossus) eggs during incubation was characterized and grouped by cluster analysis. Marked bacterial growth could be demonstrated 2 h after fertilization, and at hatching eggs were heavily overgrown. Members of the genera Pseudomonas, Alteromonas, Aeromonas, and Flavobacterium were found to dominate on the surface of both cod and halibut eggs. The filamentous bacterium Leucothrix mucor was found on eggs from both species. While growth of L. mucor on halibut eggs was sparse, cod eggs with a hairy appearance due to overgrowth by this bacterium close to hatching were frequently observed. Vibrio fischeri could be detected on cod eggs only, and pathogenic vibrios were not detected. Members of the genera Moraxella and Alcaligenes were found only on halibut eggs. Caulobacter and Seliberia spp. were observed attached to eggs dissected from cod ovaries under sterile conditions, indicating the presence of these bacteria in ovaries before spawning. Adherent strains did not demonstrate antibiotic resistance above a normal level. Attempts to
Roager, Henrik Munch; Hansen, Lea Benedicte Skov; Bahl, Martin Iain;
Little is known about how colonic transit time relates to human colonic metabolism and its importance for host health, although a firm stool consistency, a proxy for a long colonic transit time, has recently been positively associated with gut microbial richness. Here, we show that colonic transi...
Melinda A. Engevik
Full Text Available Background: The mechanisms bacteria use to proliferate and alter the normal bacterial composition remain unknown. The ability to link changes in the intestinal micro-environment, such as ion composition and pH, to bacterial proliferation is clinically advantageous for diseases that involve an altered gut microbiota, such as Inflammatory Bowel Disease, obesity and diabetes. In human and mouse intestine, the apical Na+/H+ exchangers NHE2 and NHE3 affect luminal Na+, water, and pH. Loss of NHE2 results in acidic luminal pH. Since acid resistance systems in gram-positive bacteria are well documented, we hypothesize that gram-positive bacteria would increase in representation in the acidic NHE2-/- intestine. Methods: Intestinal ion composition was measured by fame photometry and chloridometry and pH measured electrochemically. DNA extracted from intestinal flushes or from mucosal scrapings was analyzed by qRT-PCR to examine luminal and mucosa-associated bacterial populations. Epithelial mucus oligosaccharide patterns were examined by histology with FIT-C labeled lectins. Results: Although total luminal and mucosa-associated bacteria were unchanged in NHE2-/- intestine, gram-positive bacterial phyla were increased in the mucosa-associated bacterial population in a region-specific manner. The genera Clostridium and Lactobacillus were increased in the cecum and colon which corresponded to changes in NHE2-/- mucus oligosaccharide composition of mannose, N-acetyglucosamine, N-acetygalactosamine and galactose. Conclusions: Together these data indicate that changes in ion transport induce region-specific bacterial changes, which alter host mucus oligosaccharide patterns. These host-bacterial interactions provide a possible mechanism of niche-development and shed insight on how certain groups proliferate in changing environments and maintain their proliferation by altering the host.
Hage, Annina; Schneider, Katja; Schlösser, Karolin; Zimmermann, Ortrud; Hornecker, Else; Mausberg, Rainer F.; Frickmann, Hagen; Groß, Uwe; Ziebolz, Dirk
It is well known that dental caries and periodontitis are the consequence of bacterial colonization and biofilm formation on the enamel surface. The continuous presence of bacterial biofilms on the tooth surface results in demineralization of the tooth enamel and induces an inflammatory reaction of the surrounding gums (gingivitis). The retention and survival of microorganisms on toothbrushes pose a threat of recontamination especially for certain patients at risk for systemic infections originating from the oral cavity, e.g., after T-cell depleted bone marrow transplantation. Thus, the effects of different decolonization schemes on bacterial colonization of toothbrushes were analyzed, in order to demonstrate their applicability to reduce the likelihood of (auto-)reinfections. Toothbrushes were intentionally contaminated with standardized suspensions of Streptococcus mutans or Staphylococcus aureus. Afterwards, the toothbrushes were exposed to rinsing under distilled water, rinsing and drying for 24 h, 0.2% chlorhexidine-based decolonization, or ultraviolet (UV) radiation. The remaining colony forming units were compared with freshly contaminated positive controls. Each experiment was nine-fold repeated. Bi-factorial variance analysis was performed; significance was accepted at P < 0.05. All tested procedures led to a significant reduction of bacteral colonization irrespective of the toothbrush model, the brush head type, or the acitivity state. Chlorhexidine-based decolonization was shown to be superior to rinsing and slightly superior to rinsing and drying for 24 h, while UV radiation was similarly effective as chlorhexidine. UV radiation was slightly less prone to species-dependent limitations of its decolonizing effects by bristle thickness of toothbrushes than chlorhexidin. Reduction of bacterial colonization of toothbrushes might reduce the risk of maintaining bacterial infections of the upper respiratory tract. Accordingly, respective procedures are
The influence of the antitumor agent titanocene dichloride on the morphologic appearance of a heterotransplanted human colon adenocarcinoma was investigated. The first alterations in tumor cells manifested 12 h after administration of a single dose (40 mg/kg) and consisted of nuclear changes, such as chromatin condensation, enlargement of the nuclear envelope, structural changes of the nucleoli, and formation of segmented nuclei 12 h later; bundles of microfilaments, lipid droplets and inclusion bodies, often containing cellular debris, occurred in the cytoplasm. Intracytoplasmic virus particles of type A were detectable. They were obviously extruded into the extracellular space by a budding process and became extracellular virus particles of type C. Within 24 h after treatment, the mitotic index decreased from 2.5% to 0.3%. Whereas after administration of a single dose, recovery phenomena took place between 2 and 4 days, the severe destruction induced by 3-fold doses of titanocene dichloride (3 X 30 mg/kg), was apparently not reversible. These results confirm the tumor-inhibiting potency of titanocene dichloride against human colon adenocarcinoma and underline the discriminatory power of morphologic studies in the preclinical evaluation of cytostatic drugs against heterotransplanted human tumors. PMID:3384842
Monaco, Cynthia L; Gootenberg, David B; Zhao, Guoyan; Handley, Scott A; Ghebremichael, Musie S; Lim, Efrem S; Lankowski, Alex; Baldridge, Megan T; Wilen, Craig B; Flagg, Meaghan; Norman, Jason M; Keller, Brian C; Luévano, Jesús Mario; Wang, David; Boum, Yap; Martin, Jeffrey N; Hunt, Peter W; Bangsberg, David R; Siedner, Mark J; Kwon, Douglas S; Virgin, Herbert W
Human immunodeficiency virus (HIV) infection is associated with increased intestinal translocation of microbial products and enteropathy as well as alterations in gut bacterial communities. However, whether the enteric virome contributes to this infection and resulting immunodeficiency remains unknown. We characterized the enteric virome and bacterial microbiome in a cohort of Ugandan patients, including HIV-uninfected or HIV-infected subjects and those either treated with anti-retroviral therapy (ART) or untreated. Low peripheral CD4 T cell counts were associated with an expansion of enteric adenovirus sequences and this increase was independent of ART treatment. Additionally, the enteric bacterial microbiome of patients with lower CD4 T counts exhibited reduced phylogenetic diversity and richness with specific bacteria showing differential abundance, including increases in Enterobacteriaceae, which have been associated with inflammation. Thus, immunodeficiency in progressive HIV infection is associated with alterations in the enteric virome and bacterial microbiome, which may contribute to AIDS-associated enteropathy and disease progression. PMID:26962942
Cook, Laura; Barnes, Aaron; Dunny, Gary; Chatterjee, Anushree; Hu, Wei-Shou; Yarwood, Jeremy
Conjugation is an important mode of horizontal gene transfer in bacteria, enhancing the spread of antibiotic resistance. In clinical settings, biofilms are likely locations for antibiotic resistance transfer events involving nosocomial pathogens such as Enterococcus faecalis. Here we demonstrate that growth in biofilms alters the induction of conjugation by a sex pheromone in E. faecalis. Mathematical modeling suggested that a higher plasmid copy number in biofilm cells would enhance a switch...
MUHAMMAD Faisal; SHAHIDA Hasnain
The present study deals with colonization potential of plant growth promoting bacterial strains ( Ochrobactrum intermedium, Bacillus cereus and Brevibacterium sp. ) on Vigna radiata roots. The roots were heavily colonized with O. intermedium and B. cereus as compared to Brevibacterium sp. O. intermedium mainly colonized rhizoplane while B. cereus occurred both on the rhizoplane and near root zone. O. intermedium and B. cereus were found to be present both on the rhizoplane and near root zone, while Brevibacterium only in the rhizosphere in the form of groups. The cells of B. cereus were found more in the sites where root exudates were existed. From the above results it was observed that the number of O. intermedium cells were large at root exudate site. Fig 2, Tab 1, Ref 15
Cabotaje, L M; Shinnick, F L; Lopéz-Guisa, J M; Marlett, J A
The effect of psyllium on mucin secretion was determined by comparing water-soluble and -insoluble fractions of excreta from germfree rats fed a fiber-free (FF) diet or a diet containing psyllium seed husk (PS). Excreta from the same rats after colonization with a rat mixed cecal culture were separated into water-soluble, plant, and bacterial fractions to compare the remaining carbohydrate and the mass of bacteria. The sugar composition and water solubility of carbohydrate in excreta from ger...
Jun-Ho La; Tae-Wan Kim; Tae-Sik Sung; Jeoung-Woo Kang; Kyun-Ju Kim; Il-Suk Yang
AIM: Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel motility. There is increasing evidence suggesting the role of inflammation in the pathogenesis of IBS, which addresses the possibility that formerly established rat model of colitis could be used as an TBS model after the inflammation subsided.METHODS: Colitis was induced by intracolonic instillation of 4 % acetic acid in male Sprague-Dawley rats. The extent of inflammation was assessed by histological examination and myeloperoxidase (MPO) activity assay. After subsidence of colitis, the rats were subjected to rectal distension and restraint stress, then the abdominal withdrawal reflex and the number of stress-induced fecal output were measured,respectively.RESULTS: At 2 days post-induction of colitis, the colon showed characteristic inflammatory changes in histology and 8-fold increase in MPO activity. At 7 days post-induction of colitis, the histological features and MPO activity returned to normal. The rats at 7 days post-induction of colitis showed hypersensitive response to rectal distension without an accompaning change in rectal compliance, and defecated more stools than control animals when under stress.CONCLUSION: These results concur largely with the characteristic features of IBS, visceral hypersensitivity and altered defecation pattern in the absence of detectable disease, suggesting that this animal model is a methodologically convenient and useful model for studying a subset of IBS.
Thangaraju, Muthusamy; Cresci, Gail A.; Liu, Kebin; Ananth, Sudha; Gnanaprakasam, Jaya P.; Browning, Darren D.; Mellinger, John D.; Smith, Sylvia B.; Digby, Gregory J.; Lambert, Nevin A.; Prasad, Puttur D.; Ganapathy, Vadivel
Short-chain fatty acids, generated in colon by bacterial fermentation of dietary fiber, protect against colorectal cancer and inflammatory bowel disease. Among these bacterial metabolites, butyrate is biologically most relevant. GPR109A is a G-protein-coupled receptor for nicotinate, but recognizes butyrate with low affinity. Millimolar concentrations of butyrate are needed to activate the receptor. Although concentrations of butyrate in colonic lumen are sufficient to activate the receptor m...
Laverock, Bonnie; Smith, Cindy J; Tait, Karen; Osborn, A Mark; Widdicombe, Steve; Gilbert, Jack A
bacterial diversity in surface sediments and resulting in distinct bacterial communities even at depth within the burrow. In an area of high macrofaunal abundance, this could lead to alterations in the microbial transformations of important nutrients at the sediment-water interface. PMID:20596074
Reijnen, MMPJ; Holmdahl, L; Kooistra, T; Falk, P; Hendriks, T; van Goor, Harry
Background: This study assessed the peritoneal fibrinolytic response during the first week after colonic surgery in rats with and without bacterial peritonitis, and possible modulation of the response by two hyaluronan-based antiadhesive agents. Methods: A colonic anastomosis was constructed in 90 m
Reijnen, M.M.P.J.; Holmdahl, L.; Kooistra, T.; Falk, P.; Hendriks, T.; Goor, H. van
BACKGROUND: This study assessed the peritoneal fibrinolytic response during the first week after colonic surgery in rats with and without bacterial peritonitis, and possible modulation of the response by two hyaluronan-based antiadhesive agents. METHODS: A colonic anastomosis was constructed in 90 m
Adawi, Diya; Molin, Göran; Ahrné, Siv; Jeppsson, Bengt
Objective: To evaluate the effects of the administration of different bacterial strains on the extent of liver injury and bacterial translocation in an acute liver injury model. Design: Experimental study. Setting: University hospital, Sweden. Subjects: Sprague–Dawley rats. Interventions: Six different bacterial strains (Bacteroides fragilis ATCC 25285T, Enterococcus faecium No.1, Enterococcus faecium No.2, Escherichia coli F131, Lactobacillus plantarum DSM 6595, and Bifidobacterium lon...
Swidsinski, Alexander; Loening-Baucke, Vera; Schulz, Stefan; Manowsky, Julia; Verstraelen, Hans; Swidsinski, Sonja
Sections of fecal cylinders were analyzed using fluorescence in situ hybridization targeting 180 bacterial groups. Samples were collected from three groups of women (N=20 each) treated for bacterial vaginosis with ciprofloxacin+metronidazole. Group A only received the combined antibiotic regimen, whereas the A/Sb group received concomitant Saccharomyces boulardii CNCM I-745 treatment, and the A_Sb group received S. boulardii prophylaxis following the 14-day antibiotic course. The number of stool cylinders analyzed was 188 out of 228 in group A, 170 out of 228 in group A/Sb, and 172 out of 216 in group A_Sb. The colonic biomass was organized into a separate mucus layer with no bacteria, a 10-30μm broad unstirred transitional layer enriched with bacteria, and a patchy fermentative area that mixed digestive leftovers with bacteria. The antibiotics suppressed bacteria mainly in the fermentative area, whereas abundant bacterial clades retreated to the transitional mucus and survived. As a result, the total concentration of bacteria decreased only by one order. These effects were lasting, since the overall recovery of the microbial mass, bacterial diversity and concentrations were still below pre-antibiotic values 4 months after the end of antibiotic treatment. Sb-prophylaxis markedly reduced antibiotic effects and improved the recovery rates. Since the colon is a sophisticated bioreactor, the study indicated that the spatial anatomy of its biomass was crucial for its function. PMID:26723852
Abdoli, Leila; Suo, Xinkun; Li, Hua
Formation of biofilm is usually essential for the development of biofouling and crucially impacts the corrosion of marine structures. Here we report the attachment behaviors of Bacillus sp. bacteria and subsequent formation of bacterial biofilm on stainless steel and thermal sprayed aluminum coatings in artificial seawater. The colonized bacteria accelerate the corrosion of the steel plates, and markedly enhance the anti-corrosion performances of the Al coatings in early growth stage of the bacterial biofilm. After 7days incubation, the biofilm formed on the steel is heterogeneous while exhibits homogeneous feature on the Al coating. Atomic force microscopy examination discloses inception of formation of local pitting on steel plates associated with significantly roughened surface. Electrochemical testing suggests that the impact of the bacterial biofilm on the corrosion behaviors of marine structures is not decided by the biofilm alone, it is instead attributed to synergistic influence by both the biofilm and physicochemical characteristics of the substratum materials. PMID:27289310
Delgado-Aros, Silvia; Camilleri, Michael; Garcia, Montse Andreu; Burton, Duane; Busciglio, Irene
There is increased prevalence of abdominal pain and diarrhea and decreased gastric sensation with increased body mass index (BMI). Our hypothesis is that increased BMI is associated with increased colonic motility and sensation. The study aim was to assess effect of BMI on colonic sensory and motor functions and transit. We used a database of colonic tone, compliance, and perception of distensions measured by intracolonic, barostat-controlled balloon, and gastrointestinal transit was measured...
Ehrström, Sophia; Daroczy, Katalin; Rylander, Eva; Samuelsson, Carolina; Johannesson, Ulrika; Anzén, Bo; Påhlson, Carl
This randomized double-blind placebo controlled study assessed the vaginal colonization of lactic acid bacteria and clinical outcome. Vaginal capsules containing L gasseri LN40, Lactobacillus fermentum LN99, L. casei subsp. rhamnosus LN113 and P. acidilactici LN23, or placebos were administered for five days to 95 women after conventional treatment of bacterial vaginosis and/or vulvovaginal candidiasis. Vulvovaginal examinations and vaginal samplings were performed before and after administration, after the first and second menstruation, and after six months. Presence of LN strains was assessed using RAPD analysis. LN strains were present 2-3 days after administration in 89% of the women receiving LN strains (placebo: 0%, p vulvovaginal candidiasis lead to vaginal colonization, somewhat fewer recurrences and less malodorous discharge. PMID:20472091
Azoxymethane (AOM) or 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in rats shares many phenotypical similarities with human sporadic colon cancer and is a reliable model for identifying chemopreventive agents. Genetic mutations relevant to human colon cancer have been described in this model, but comprehensive gene expression and genomic analysis have not been reported so far. Therefore, we applied genome-wide technologies to study variations in gene expression and genomic alterations in DMH-induced colon cancer in F344 rats. For gene expression analysis, 9 tumours (TUM) and their paired normal mucosa (NM) were hybridized on 4 × 44K Whole rat arrays (Agilent) and selected genes were validated by semi-quantitative RT-PCR. Functional analysis on microarray data was performed by GenMAPP/MappFinder analysis. Array-comparative genomic hybridization (a-CGH) was performed on 10 paired TUM-NM samples hybridized on Rat genome arrays 2 × 105K (Agilent) and the results were analyzed by CGH Analytics (Agilent). Microarray gene expression analysis showed that Defcr4, Igfbp5, Mmp7, Nos2, S100A8 and S100A9 were among the most up-regulated genes in tumours (Fold Change (FC) compared with NM: 183, 48, 39, 38, 36 and 32, respectively), while Slc26a3, Mptx, Retlna and Muc2 were strongly down-regulated (FC: -500; -376, -167, -79, respectively). Functional analysis showed that pathways controlling cell cycle, protein synthesis, matrix metalloproteinases, TNFα/NFkB, and inflammatory responses were up-regulated in tumours, while Krebs cycle, the electron transport chain, and fatty acid beta oxidation were down-regulated. a-CGH analysis showed that four TUM out of ten had one or two chromosomal aberrations. Importantly, one sample showed a deletion on chromosome 18 including Apc. The results showed complex gene expression alterations in adenocarcinomas encompassing many altered pathways. While a-CGH analysis showed a low degree of genomic imbalance, it is interesting to
de Sousa, Natanael Teixeira Alves; Gomes, Rosana Caetano; Santos, Marcos Ferracioli; Brandino, Hugo Evangelista; Martinez, Roberto; de Jesus Guirro, Rinaldo Roberto
Low-level laser therapy (LLLT) is used in chronic wounds due to its healing effects. However, bacterial species may colonize these wounds and the optimal parameters for effective bacterial inhibition are not clear. The aim of this study was to analyze the effect of LLLT on bacterial growth in vitro. Bacterial strains including Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were suspended in saline solution at a concentration of 10(3) cells/ml and exposed to laser irradiation at wavelengths of 660, 830, and 904 nm at fluences of 0 (control), 3, 6, 12, 18, and 24 J/cm(2). An aliquot of the irradiated suspension was spread on the surface of petri plates and incubated at 37 °C for quantification of colony-forming unit after 24, 48, and 72 h. Laser irradiation inhibited the growth of S. aureus at all wavelengths and fluences higher than 12 J/cm(2), showing a strong correlation between increase in fluence and bacterial inhibition. However, for P. aeruginosa, LLLT inhibited growth at all wavelengths only at a fluence of 24 J/cm(2). E. coli had similar growth inhibition at a wavelength of 830 nm at fluences of 3, 6, 12, and 24 J/cm(2). At wavelengths of 660 and 904 nm, growth inhibition was only observed at fluences of 12 and 18 J/cm(2), respectively. LLLT inhibited bacterial growth at all wavelengths, for a maximum of 72 h after irradiation, indicating a correlation between bacterial species, fluence, and wavelength. PMID:26886585
Koutsoudis, Maria D.; Tsaltas, Dimitrios; Minogue, Timothy D.; von Bodman, Susanne B.
The phytopathogenic bacterium Pantoea stewartii subsp. stewartii synthesizes stewartan exo/capsular polysaccharide (EPS) in a cell density-dependent manner governed by the EsaI/EsaR quorum-sensing (QS) system. This study analyzes biofilm development and host colonization of the WT and QS regulatory mutant strains of P. stewartii. First, we show that the cell density-dependent synthesis of stewartan EPS, governed by the EsaI/EsaR QS system, is required for proper bacterial adhesion and develop...
May, Addison K; Gleason, Thomas G.; Sawyer, Robert G.; Pruett, Timothy L.
Alpha-hemolysin (Hly) is a common exotoxin produced by Escherichia coli that enhances virulence in a number of clinical infections. The addition of hemolysin production to laboratory bacterial strains is known to increase the lethality of E. coli peritonitis. However, the mechanisms involved have not been determined and the contribution of hemolysin to the alterations in the host intraperitoneal environment and the leukocyte response is not known. Utilizing a rat peritonitis model, we show th...
Marupakula, Srisailam; Mahmood, Shahid; Finlay, Roger D
Symbiotic ectomycorrhizal tree roots represent an important niche for interaction with bacteria since the fungi colonizing them have a large surface area and receive a direct supply of photosynthetically derived carbon. We examined individual root tips of Pinus sylvestris at defined time points between 5 days and 24 weeks, identified the dominant fungi colonizing each root tip using Sanger sequencing and the bacterial communities colonizing individual root tips by 454 pyrosequencing. Bacterial colonization was extremely dynamic with statistically significant variation in time and increasing species richness until week 16 (3477 operational taxonomic units). Bacterial community structure of roots colonized by Russula sp. 6 GJ-2013b, Piloderma spp., Meliniomyces variabilis and Paxillus involutus differed significantly at weeks 8 and 16 but diversity declined and significant differences were no longer apparent at week 24. The most common genera were Burkholderia, Sphingopyxsis, Dyella, Pseudomonas, Acinetobacter, Actinospica, Aquaspirillum, Acidobacter Gp1, Sphingomonas, Terriglobus, Enhydrobacter, Herbaspirillum and Bradyrhizobium. Many genera had high initial abundance at week 8, declining with time but Dyella and Terriglobus increased in abundance at later time points. In roots colonized by Piloderma spp. several other bacterial genera, such as Actinospica, Bradyrhizobium, Acidobacter Gp1 and Rhizomicrobium appeared to increase in abundance at later sampling points. PMID:26521936
Cabotaje, L M; Shinnick, F L; Lopéz-Guisa, J M; Marlett, J A
The effect of psyllium on mucin secretion was determined by comparing water-soluble and -insoluble fractions of excreta from germfree rats fed a fiber-free (FF) diet or a diet containing psyllium seed husk (PS). Excreta from the same rats after colonization with a rat mixed cecal culture were separated into water-soluble, plant, and bacterial fractions to compare the remaining carbohydrate and the mass of bacteria. The sugar composition and water solubility of carbohydrate in excreta from germfree rats fed FF diets indicated that a primary fermentable substrate was mucin. PS increased fecal excretion of mucin-derived sugars almost threefold in germfree rats. Fecal carbohydrate was reduced from 619 to 237 mumol/g of dry feces and mostly in the bacterial fraction when rats fed an FF diet were colonized. The total sugar content and the amount of muramic acid, but not bacterial counts and mass, indicated that PS increased fecal bacteria. Fractionation of excreta from PS-fed rats was complicated by a gel which, based on sugar composition, was PS. Sugar composition of the water-soluble fraction from excreta from PS-fed rats suggested that it contained some bacterial component, possibly exopolysaccharides and some of the PS, but not mucin. PS digestibility ranged from 60 to 80%, depending on what fecal fraction was used for output. Because of the presence of PS-derived sugars in the gel and soluble fraction, it was not possible to determine which, if any, of the PS digestibilities was correct. PMID:8017918
Nordgård, Lise; Nguyen, Thuy; Midtvedt, Tore; Benno, Yoshimi; Traavik, Terje; Nielsen, Kaare M
Biological risk assessment of food containing recombinant DNA has exposed knowledge gaps related to the general fate of DNA in the gastrointestinal tract (GIT). Here, a series of experiments is presented that were designed to determine if genetic transformation of the naturally competent bacterium Acinetobacter baylyi BD413 occurs in the GIT of mice and rats, with feed-introduced bacterial DNA containing a kanamycin resistance gene (nptII). Strain BD413 was found in various gut locations in germ-free mice at 10(3)-10(5) CFU per gram GIT content 24-48 h after administration. However, subsequent DNA exposure of the colonized mice did not result in detectable bacterial transformants, with a detection limit of 1 transformant per 10(3)-10(5) bacteria. Further attempts to increase the likelihood of detection by introducing weak positive selection with kanamycin of putative transformants arising in vivo during a 4-week-long feeding experiment (where the mice received DNA and the recipient cells regularly) did not yield transformants either. Moreover, the in vitro exposure of actively growing A. baylyi cells to gut contents from the stomach, small intestine, cecum or colon contents of rats (with a normal microbiota) fed either purified DNA (50 microg) or bacterial cell lysates did not produce bacterial transformants. The presence of gut content of germfree mice was also highly inhibitory to transformation of A. baylyi, indicating that microbially-produced nucleases are not responsible for the sharp 500- to 1,000,000-fold reduction of transformation frequencies seen. Finally, a range of isolates from the genera Enterococcus, Streptococcus and Bifidobacterium spp. was examined for competence expression in vitro, without yielding any transformants. In conclusion, model choice and methodological constraints severely limit the sample size and, hence, transfer frequencies that can be measured experimentally in the GIT. Our observations suggest the contents of the GIT shield or
Hill, Philip J.; Stritzker, Jochen; Scadeng, Miriam; Geissinger, Ulrike; Haddad, Daniel; Basse-Lüsebrink, Thomas C.; Gbureck, Uwe; Jakob, Peter; Szalay, Aladar A.
Background Recent studies have shown that human ferritin can be used as a reporter of gene expression for magnetic resonance imaging (MRI). Bacteria also encode three classes of ferritin-type molecules with iron accumulation properties. Methods and Findings Here, we investigated whether these bacterial ferritins can also be used as MRI reporter genes and which of the bacterial ferritins is the most suitable reporter. Bacterial ferritins were overexpressed in probiotic E. coli Nissle 1917. Cul...
Full Text Available Abstract Background Postnatal regulation of the small intestinal mucus layer is potentially important in the development of adult gut functionality. We hypothesized that the nature of bacterial colonization affects mucus gene regulation in early life. We thus analyzed the influence of the presence of a conventional microbiota as well as two selected monocolonizing bacterial strains on the transcription of murine genes involved in mucus layer development during the first week of life. Mouse pups (N = 8/group from differently colonized dams: Germ-free (GF, conventional specific pathogen free (SPF, monocolonized with either Lactobacillus acidophilus NCFM (Lb or Escherichia coli Nissle (Ec were analyzed by qPCR on isolated ileal tissue sections from postnatal days 1 and 6 (PND1, PND6 after birth with respect to: (i transcription of specific genes involved in mucus production (Muc1-4, Tff3 and (ii amounts of 16S rRNA of Lactobacillus and E. coli. Quantification of 16S rRNA genes was performed to obtain a measure for amounts of colonized bacteria. Results We found a microbiota-independent transcriptional increase of all five mucus genes from PND1 to PND6. Furthermore, the relative level of transcription of certain mucus genes on PND1 was increased by the presence of bacteria. This was observed for Tff3 in the SPF, Ec, and Lb groups; for Muc2 in SPF; and for Muc3 and Muc4 in Ec and Lb, respectively. Detection of bacterial 16S rRNA genes levels above the qPCR detection level occurred only on PND6 and only for some of the colonized animals. On PND6, we found significantly lower levels of Muc1, Muc2 and Muc4 gene transcription for Lb animals with detectable Lactobacillus levels as compared to animals with Lactobacillus levels below the detection limit. Conclusions In summary, our data show that development of the expression of genes encoding secreted (Muc2/Tff3 and membrane-bound (Muc1/Muc3/Muc4 mucus regulatory proteins, respectively, is distinct and
Christophersen, C. T.; Petersen, Anne; Licht, Tine Rask;
High dietary intakes of some protein sources, including soy protein, can increase colonic DNA damage in animals, whereas some carbohydrates attenuate this. We investigated whether inulin and xylo-oligosaccharides (XOS) could be protective against DNA strand breaks by adding them to a human colonic...... simulator consisting of a proximal vessel (PV) (pH 5.5) and a distal vessel (DV) (pH 6.8) inoculated with human faeces and media containing soy protein. Genotoxicity of the liquid phase and microbial population changes in the vessels were measured. Soy protein (3%) was fermented with 1% low amylose...... cornstarch for 10 day followed by soy protein with 1% XOS or 1% inulin for 10 day. Inulin did not alter genotoxicity but XOS significantly reduced PV genotoxicity and increased DV genotoxicity. Inulin and XOS significantly increased butyrate concentration in the DV but not PV. Numbers of the key butyrate...
Beman, J. Michael; Carolan, Molly T.
Oceanic oxygen minimum zones (OMZs) have a central role in biogeochemical cycles and are expanding as a consequence of climate change, yet how deoxygenation will affect the microbial communities that control these cycles is unclear. Here we sample across dissolved oxygen gradients in the oceans’ largest OMZ and show that bacterial richness displays a unimodal pattern with decreasing dissolved oxygen, reaching maximum values on the edge of the OMZ and decreasing within it. Rare groups on the OMZ margin are abundant at lower dissolved oxygen concentrations, including sulphur-cycling Chromatiales, for which 16S rRNA was amplified from extracted RNA. Microbial species distribution models accurately replicate community patterns based on multivariate environmental data, demonstrate likely changes in distributions and diversity in the eastern tropical North Pacific Ocean, and highlight the sensitivity of key bacterial groups to deoxygenation. Through these mechanisms, OMZ expansion may alter microbial composition, competition, diversity and function, all of which have implications for biogeochemical cycling in OMZs.
Najdi, Rani; Syed, Adeela; Arce, Laura; Theisen, Heidi; Ting, Ju-Hui T.; Atcha, Fawzia; Nguyen, Anthony V.; Martinez, Micaela; Randall F. Holcombe; Edwards, Robert A.; Marsh, J. Lawrence; Waterman, Marian L
Constitutive activation of the Wnt/β-catenin pathway has been implicated as the primary cause of colon cancer. However, the major transducers of Wnt signaling in the intestine, TCF-1 and TCF-4, have opposing functions. Knock-out of TCF-4 suppresses growth and maintenance of crypt stem cells, while knock-out of TCF-1 leads to adenomas. These phenotypes suggest that TCF-4 is Wnt-promoting while TCF-1 acts like a tumor suppressor. Our study of TCF expression in human colon crypts reveals a mecha...
Kielak, Anna; Cretoiu, Mariana; Semenov, Alexander; Sørensen, Søren Johannes; van Elsas, Jan
Chitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment...... in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S r......RNA and chiA genes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity of chiA gene types in soil is enormous and (i) that different chiA gene types are selected...
Koutsoudis, Maria D; Tsaltas, Dimitrios; Minogue, Timothy D; von Bodman, Susanne B
The phytopathogenic bacterium Pantoea stewartii subsp. stewartii synthesizes stewartan exo/capsular polysaccharide (EPS) in a cell density-dependent manner governed by the EsaI/EsaR quorum-sensing (QS) system. This study analyzes biofilm development and host colonization of the WT and QS regulatory mutant strains of P. stewartii. First, we show that the cell density-dependent synthesis of stewartan EPS, governed by the EsaI/EsaR QS system, is required for proper bacterial adhesion and development of spatially defined, 3D biofilms. Second, a nonvirulent mutant lacking the esaI gene adheres strongly to surfaces and develops densely packed, less structurally defined biofilms in vitro. This strain appears to be arrested in a low cell density developmental mode. Exposure of this strain to exogenous N-acyl-homoserine lactone counteracts this adhesion phenotype. Third, QS mutants lacking the EsaR repressor attach poorly to surfaces and form amorphous biofilms heavily enmeshed in excess EPS. Fourth, the WT strain disseminates efficiently within the xylem, primarily in a basipetal direction. In contrast, the two QS mutant strains remain largely localized at the site of infection. Fifth, and most significantly, epifluorescence microscopic imaging of infected leaf tissue and excised xylem vessels reveals that the bacteria colonize the xylem with unexpected specificity, particularly toward the annular rings and spiral secondary wall thickenings of protoxylem, as opposed to indiscriminate growth to fill the xylem lumen. These observations are significant to bacterial plant pathogenesis in general and may reveal targets for disease control. PMID:16585516
Yang, Zhiman; Guo, Rongbo; Shi, Xiaoshuang; He, Shuai; Wang, Lin; Dai, Meng; Qiu, Yanling; Dang, Xiaoxiao
Bioaugmentation can facilitate hydrogen production from complex organic substrates, but it still is unknown how indigenous microbial communities respond to the added bacteria. Here, using a Hydrogenispora ethanolica LX-B (named as LX-B) bioaugmentation experiments, the distribution of metabolites and the responses of indigenous bacterial communities were investigated via batch cultivation (BC) and repeated batch cultivation (RBC). In BC the LX-B/sludge ratio of 0.12 achieved substantial high hydrogen yield, which was over twice that of control. In RBC one-time bioaugmentation and repeated batch bioaugmentation of LX-B resulted in the hydrogen yield that was average 1.2-fold and 0.8-fold higher than that in control, respectively. This improved hydrogen production performance mainly benefited from a shift in composition of the indigenous bacterial community caused by LX-B bioaugmentation. The findings represented an important step in understanding the relationship between bioaugmentation, a shift in bacterial communities, and altered bioreactor performance. PMID:27023388
Jump, Robin L. P.; Polinkovsky, Alex; Hurless, Kelly; Sitzlar, Brett; Eckart, Kevin; Tomas, Myreen; Deshpande, Abhishek; Nerandzic, Michelle M.; Donskey, Curtis J.
Background The intestinal microbiota protect the host against enteric pathogens through a defense mechanism termed colonization resistance. Antibiotics excreted into the intestinal tract may disrupt colonization resistance and alter normal metabolic functions of the microbiota. We used a mouse model to test the hypothesis that alterations in levels of bacterial metabolites in fecal specimens could provide useful biomarkers indicating disrupted or intact colonization resistance after antibioti...
Full Text Available The outcome of an interaction between plant growth promoting rhizobacteria and plants may depend on the chemical composition of root exudates (REs. We report the colonization of tobacco, and not groundnut, roots by a non-rhizospheric Bacillus cereus (MTCC 430. There was a differential alteration in the cell wall components of B. cereus in response to the REs from tobacco and groundnut. Attenuated total reflectance infrared spectroscopy revealed a split in amide I region of B. cereus cells exposed to tobacco-root exudates (TRE, compared to those exposed to groundnut-root exudates (GRE. In addition, changes in exopolysaccharides and lipid-packing were observed in B. cereus grown in TRE-amended minimal media that were not detectable in GRE-amended media. Cell-wall proteome analyses revealed upregulation of oxidative stress-related alkyl hydroperoxide reductase, and DNA-protecting protein chain (Dlp-2, in response to GRE and TRE, respectively. Metabolism-related enzymes like 2-amino-3-ketobutyrate coenzyme A ligase and 2-methylcitrate dehydratase and a 60 kDa chaperonin were up-regulated in response to TRE and GRE. In response to B. cereus, the plant roots altered their exudate-chemodiversity with respect to carbohydrates, organic acids, alkanes, and polyols. TRE-induced changes in surface components of B. cereus may contribute to successful root colonization and subsequent plant growth promotion.
Lejeune, Manigandan; Moreau, France; Chadee, Kris
Prostaglandin E2 (PGE2) is a bioactive lipid mediator that exerts its biological function through interaction with four different subtypes of E-Prostanoid receptor namely EP1, EP2, EP3 and EP4. It has been known that EP2 receptor is differentially over-expressed in the epithelia of inflamed human colonic mucosa. However, the significance of the differential expression in altering epithelial barrier function is not known. In this study, we used Caco-2 cells expressing EP2 receptor, either high (EP2S) or low (EP2A), as a model epithelia and determined the barrier function of these cell monolayers by measuring the trans epithelial resistance (TER). Basal TER of EP2A (but not EP2S) monolayer was significantly lower suggesting a loss of colonic epithelial barrier integrity. In comparison, the TER of wild type Caco-2 was decreased in response to an EP2 receptor specific antagonist (AH-6809) indicating an important role for EP2 receptor in the maintenance of epithelial barrier function. The decrease TER in EP2A monolayer corresponded with a significant loss of the tight junction (TJ) protein claudin-4 without affecting other major TJ proteins. Similarly, EP2 receptor antagonism/siRNA based silencing significantly decreased claudin-4 expression in EP2S cells. Surprisingly, alteration in claudin-4 was not transcriptionally regulated in EP2A cells but rather undergoes increased proteosomal degradation. Moreover, among the TER compromising cytokines examined (IL-8, IL-1β, TNF-α, IFN-γ) only IFN-γ was significantly up regulated in EP2A cells. However, IFN-γ did not significantly decreased claudin-4 expression in Caco-2 cells indicating no role for IFN-γ in degrading claudin-4. We conclude that differential down-regulation of EP2 receptor play a major role in compromising colonic epithelial barrier function by selectively increasing proteosomal degradation of claudin-4. PMID:25396731
In this thesis, I describe experiments aimed at understanding bacterial population dynamics in ecosystems that are spatially structured at the micro-scale. We combine microfabrication and microfluidics to create synthetic ecosystems that have a complex yet well-defined geometry and chemical composit
Overbeek, van L.S.; Saikkonen, Kari
Research on different endophyte taxa and the related scientific disciplines have largely developed separately, and comprehensive community-level studies on bacterial and fungal interactions and their importance are lacking. Here, we discuss the transmission modes of bacteria and fungi and the nat
Rong Fan; Travis Emery; Yongguo Zhang; Yuxuan Xia; Jun Sun; Jiandi Wan
During cancer metastasis, circulating tumor cells constantly experience hemodynamic shear stress in the circulation. Cellular responses to shear stress including cell viability and proliferation thus play critical roles in cancer metastasis. Here, we developed a microfluidic approach to establish a circulatory microenvironment and studied circulating human colon cancer HCT116 cells in response to a variety of magnitude of shear stress and circulating time. Our results showed that cell viabili...
Hofmanová, Jiřina; Stixová, Lenka; Netíková, Jaromíra; Cigánek, M.; Slavík, J.; Machala, M.; Kozubík, Alois
Gothenburg, 2009. s. 75. [Frontier Lipidology: Lipidomics in Health and Disease. 10.05.2009-13.05.2009, Gothenburg] R&D Projects: GA ČR(CZ) GA524/07/1178; GA AV ČR(CZ) 1QS500040507 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : colon cancer * fatty acids * apoptosis Subject RIV: AQ - Safety, Health Protection, Human - Machine
Jardí Pujol, Ferran
We determined NGF involvement in MMCs and colonic motor alterations in an ovalbumin (OVA)-induced gut dysfunction model in rats. Animals received OVA (6 weeks), with/without simultaneous K252a (TrkA antagonist) treatment. MMCs, rat mast cell protease II (RMCPII) levels and colonic contractility in vitro were assessed. OVA increased MMC density and RMCPII concentration. Spontaneous contractility was similar in both groups and inhibited by K252a. Carbachol responses were increased by OVA in a K...
Zhong, Yu; Anderl, Florian; Kruse, Tobias; Schindele, Franziska; Jagusztyn-Krynicka, Elżbieta Katarzyna; Fischer, Wolfgang; Gerhard, Markus; Mejías-Luque, Raquel
The Dsb protein family is responsible for introducing disulfide bonds into nascent proteins in prokaryotes, stabilizing the structure of many proteins. Helicobacter pylori HP0231 is a Dsb-like protein, shown to catalyze disulfide bond formation and to participate in redox homeostasis. Notably, many H. pylori virulence factors are stabilized by the formation of disulfide bonds. By employing H. pylori HP0231 deficient strains we analyzed the effect of lack of this bacterial protein on the funct...
In this thesis, I describe experiments aimed at understanding bacterial population dynamics in ecosystems that are spatially structured at the micro-scale. We combine microfabrication and microfluidics to create synthetic ecosystems that have a complex yet well-defined geometry and chemical composition. Bacteria that inhabit such ecosystems can be observed at high spatiotemporal resolution using fluorescence microscopy. Using this experimental approach we have gained deeper insight into diver...
Nagy, Zsolt; Acs, Bence; Butz, Henriett; Feldman, Karolina; Marta, Alexa; Szabo, Peter M; Baghy, Kornelia; Pazmany, Tamas; Racz, Karoly; Liko, Istvan; Patocs, Attila
The glucocorticoid receptor (GR) plays a crucial role in inflammatory responses. GR has several isoforms, of which the most deeply studied are the GRα and GRß. Recently it has been suggested that in addition to its negative dominant effect on GRα, the GRß may have a GRα-independent transcriptional activity. The GRß isoform was found to be frequently overexpressed in various autoimmune diseases, including inflammatory bowel disease (IBD). In this study, we wished to test whether the gene expression profile found in a GRß overexpressing intestinal cell line (Caco-2GRß) might mimic the gene expression alterations found in patients with IBD. Whole genome microarray analysis was performed in both normal and GRß overexpressing Caco-2 cell lines with and without dexamethasone treatment. IBD-related genes were identified from a meta-analysis of 245 microarrays available in online microarray deposits performed on intestinal mucosa samples from patients with IBD and healthy individuals. The differentially expressed genes were further studied using in silico pathway analysis. Overexpression of GRß altered a large proportion of genes that were not regulated by dexamethasone suggesting that GRß may have a GRα-independent role in the regulation of gene expression. About 10% of genes differentially expressed in colonic mucosa samples from IBD patients compared to normal subjects were also detected in Caco-2 GRß intestinal cell line. Common genes are involved in cell adhesion and cell proliferation. Overexpression of GRß in intestinal cells may affect appropriate mucosal repair and intact barrier function. The proposed novel role of GRß in intestinal epithelium warrants further studies. PMID:26480216
Vissing, Nadja Hawwa
, the variation has been explained by environmental exposures such as day care attendance, breastfeeding, crowding, siblings, tobacco smoke exposure, low socioeconomic status, and male sex, but these risk factors only explain a minor proportion of the variation. Confidence in the results is hampered by...... association between neonatal airway colonization and risk of the LRI in a validated study cohort, and whether a possible association could be reflected in the early immune response to airway pathogens. In study I we aimed to ascertain the quality of information on child’s health, including asthma, allergy...... characterized by perturbed production of several cytokines, rather than production of one specific cytokine, and was independent of concurrent asthma. This suggests that children at risk of future LRI present a distinct systemic immune response upon exposure to common airway pathogens in early life, possibly...
Shtylla, Blerta; Keener, James P.
The generation of directed movement of cellular components frequently requires the rectification of Brownian motion. Molecular motor enzymes that use ATP to walk on filamentous tracks are typically involved in cell transport, however, a track-altering motor can arise when an enzyme interacts with and alters its track. In Caulobacter crescentus and other bacteria, an active DNA partitioning (Par) apparatus is employed to segregate replicated chromosome regions to specific locations in dividing cells. The Par apparatus is composed of two proteins: ParA, an ATPase that can form polymeric structures on the nucleoid, and ParB, a protein that can bind and destabilize ParA structures. It has been proposed that the ParB-mediated alteration of ParA structures could be responsible for generating the directed movement of DNA during bacterial division. How precisely these actions are coordinated and translated into directed movement is not clear. In this paper we consider the C. crescentus segregation apparatus as an example of a track altering motor that operates using a so-called burnt-bridge mechanism. We develop and analyze mathematical models that examine how diffusion and ATP-hydrolysis-mediated monomer removal (or cleaving) can be combined to generate directed movement. Using a mean first passage approach, we analytically calculate the effective ParA track-cleaving velocities, effective diffusion coefficient, and other higher moments for the movement a ParB protein cluster that breaks monomers away at random locations on a single ParA track. Our model results indicate that cleaving velocities and effective diffusion constants are sensitive to ParB-induced ATP hydrolysis rates. Our analytical results are in excellent agreement with stochastic simulation results.
David M Bulmer
Full Text Available Although there have been great advances in our understanding of the bacterial cytoskeleton, major gaps remain in our knowledge of its importance to virulence. In this study we have explored the contribution of the bacterial cytoskeleton to the ability of Salmonella to express and assemble virulence factors and cause disease. The bacterial actin-like protein MreB polymerises into helical filaments and interacts with other cytoskeletal elements including MreC to control cell-shape. As mreB appears to be an essential gene, we have constructed a viable ΔmreC depletion mutant in Salmonella. Using a broad range of independent biochemical, fluorescence and phenotypic screens we provide evidence that the Salmonella pathogenicity island-1 type three secretion system (SPI1-T3SS and flagella systems are down-regulated in the absence of MreC. In contrast the SPI-2 T3SS appears to remain functional. The phenotypes have been further validated using a chemical genetic approach to disrupt the functionality of MreB. Although the fitness of ΔmreC is reduced in vivo, we observed that this defect does not completely abrogate the ability of Salmonella to cause disease systemically. By forcing on expression of flagella and SPI-1 T3SS in trans with the master regulators FlhDC and HilA, it is clear that the cytoskeleton is dispensable for the assembly of these structures but essential for their expression. As two-component systems are involved in sensing and adapting to environmental and cell surface signals, we have constructed and screened a panel of such mutants and identified the sensor kinase RcsC as a key phenotypic regulator in ΔmreC. Further genetic analysis revealed the importance of the Rcs two-component system in modulating the expression of these virulence factors. Collectively, these results suggest that expression of virulence genes might be directly coordinated with cytoskeletal integrity, and this regulation is mediated by the two-component system
Lisa M Parsons
Full Text Available Caenorabditis elegans bus-4 glycosyltransferase mutants are resistant to infection by Microbacterium nematophilum, Yersinia pestis and Yersinia pseudotuberculosis and have altered susceptibility to two Leucobacter species Verde1 and Verde2. Our objective in this study was to define the glycosylation changes leading to this phenotype to better understand how these changes lead to pathogen resistance. We performed MALDI-TOF MS, tandem MS and GC/MS experiments to reveal fine structural detail for the bus-4 N- and O-glycan pools. We observed dramatic changes in O-glycans and moderate ones in N-glycan pools compared to the parent strain. Ce core-I glycans, the nematode's mucin glycan equivalent, were doubled in abundance, halved in charge and bore shifts in terminal substitutions. The fucosyl O-glycans, Ce core-II and neutral fucosyl forms, were also increased in abundance as were fucosyl N-glycans. Quantitative expression analysis revealed that two mucins, let-653 and osm-8, were upregulated nearly 40 fold and also revealed was a dramatic increase in GDP-Man 4,6 dehydratease expression. We performed detailed lectin binding studies that showed changes in glycoconjugates in the surface coat, cuticle surface and intestine. The combined changes in cell surface glycoconjugate distribution, increased abundance and altered properties of mucin provide an environment where likely the above pathogens are not exposed to normal glycoconjugate dependent cues leading to barriers to these bacterial infections.
Ward, Melissa J.; Selva, Laura; Guinane, Caitriona M.; González-Muñoz, Beatriz M.; Tristan, Anne; Foster, Simon J; Fitzgerald, J. Ross; Penadés, José R.
The capacity of microbial pathogens to alter their host-tropism leading to epidemics in distinct host-species populations is a global public and veterinary health concern. In order to investigate the molecular basis of a bacterial host-switching event in a tractable host-species, we traced the evolutionary trajectory of the common rabbit clone of Staphylococcus aureus. We report that it evolved through a likely human-to-rabbit host jump over 40 years ago, and that only a single natural nucleotide mutation was required and sufficient to convert a human-specific S. aureus strain into one which could infect rabbits. Related mutations were identified at the same locus in other rabbit strains of distinct clonal origin, consistent with convergent evolution. This first report of a single mutation that was sufficient to alter the host-tropism of a micro-organism during its evolution highlights the capacity of some pathogens to readily expand into novel host-species populations. PMID:25685890
Mari, X.; Kiørboe, Thomas
distribution followed a power law, with the abundance of particles scaling with particle diameter((B+1)). The seasonal average estimate of beta (2.3) was not significantly different from three, consistent with TEP being formed by shear coagulation from smaller particles. However, date-specific estimates of...... TEP size raised to an exponent of similar to 1.5. We argue that this is consistent with TEP being fractal. Between 0.5 and 20% of the total bacterial population were attached to TEP. Crude estimates of TEP carbon concentrations combined with considerations of turnover times suggest that TEP and their...... colloidal precursors may represent a hitherto understudied but potentially significant pathway for dissolved organic carbon in the ocean...
May, A K; Gleason, T G; Sawyer, R G; Pruett, T L
Alpha-hemolysin (Hly) is a common exotoxin produced by Escherichia coli that enhances virulence in a number of clinical infections. The addition of hemolysin production to laboratory bacterial strains is known to increase the lethality of E. coli peritonitis. However, the mechanisms involved have not been determined and the contribution of hemolysin to the alterations in the host intraperitoneal environment and the leukocyte response is not known. Utilizing a rat peritonitis model, we show that wild-type hemolytic E. coli strains have a significant competitive advantage over nonhemolytic strains within the peritoneum. To examine the specific contribution of Hly to E. coli-induced virulence and alterations within the peritoneum, a mixed peritonitis model of E. coli, Bacteroides fragilis, and sterile fecal adjuvant was used. Three transformed E. coli strains were utilized: one strongly secretes active hemolysin (WAF 270), a second secretes active hemolysin but a reduced amount (WAF 260), and the third does not produce hemolysin (WAF 108). After an equal inoculum of each of the three strains, WAF 270 produced a markedly increased lethality and an increased recovery of both E. coli and B. fragilis from the host relative to the other strains. Changes in the intraperitoneal pH, degree of erythrocyte lysis, and recruitment and viability of leukocytes within the peritoneum following the induction of peritonitis differed significantly between the strongly hemolytic and nonhemolytic strains. Induction of peritonitis with WAF 270 caused a pronounced decrease in intraperitoneal pH, lysis of most of the intraperitoneal erythrocytes, and a marked decrease in recoverable viable leukocytes compared to WAF 108. Thus, hemolysin production by E. coli within the peritoneum may alter not only the host's ability to control the hemolytic strain itself but also other organisms. PMID:10603385
Mara Jana Broadhurst
Full Text Available Idiopathic chronic diarrhea (ICD is a leading cause of morbidity amongst rhesus monkeys kept in captivity. Here, we show that exposure of affected animals to the whipworm Trichuris trichiura led to clinical improvement in fecal consistency, accompanied by weight gain, in four out of the five treated monkeys. By flow cytometry analysis of pinch biopsies collected during colonoscopies before and after treatment, we found an induction of a mucosal T(H2 response following helminth treatment that was associated with a decrease in activated CD4(+ Ki67+ cells. In parallel, expression profiling with oligonucleotide microarrays and real-time PCR analysis revealed reductions in T(H1-type inflammatory gene expression and increased expression of genes associated with IgE signaling, mast cell activation, eosinophil recruitment, alternative activation of macrophages, and worm expulsion. By quantifying bacterial 16S rRNA in pinch biopsies using real-time PCR analysis, we found reduced bacterial attachment to the intestinal mucosa post-treatment. Finally, deep sequencing of bacterial 16S rRNA revealed changes to the composition of microbial communities attached to the intestinal mucosa following helminth treatment. Thus, the genus Streptophyta of the phylum Cyanobacteria was vastly increased in abundance in three out of five ICD monkeys relative to healthy controls, but was reduced to control levels post-treatment; by contrast, the phylum Tenericutes was expanded post-treatment. These findings suggest that helminth treatment in primates can ameliorate colitis by restoring mucosal barrier functions and reducing overall bacterial attachment, and also by altering the communities of attached bacteria. These results also define ICD in monkeys as a tractable preclinical model for ulcerative colitis in which these effects can be further investigated.
McKenney, Erin A; Williamson, Lauren; Yoder, Anne D; Rawls, John F; Bilbo, Staci D; Parker, William
The microbiome is now widely recognized as being important in health and disease, and makes up a substantial subset of the biome within the ecosystem of the vertebrate body. At the same time, multicellular, eukaryotic organisms such as helminths are being recognized as an important component of the biome that shaped the evolution of our genes. The absence of these macroscopic organisms during the early development and life of humans in Western culture probably leads to a wide range of human immunological diseases. However, the interaction between the microbiome and macroscopic components of the biome remains poorly characterized. In this study, the microbiome of the cecum in rats colonized for 2 generations with the small intestinal helminth Hymenolepis diminuta was evaluated. The introduction of this benign helminth, which is of considerable therapeutic interest, led to several changes in the cecal microbiome. Most of the changes were within the Firmicutes phylum, involved about 20% of the total bacteria, and generally entailed a shift from Bacilli to Clostridia species in the presence of the helminth. The results point toward ecological relationships between various components of the biome, with the observed shifts in the microbiome suggesting potential mechanisms by which this helminth might exert therapeutic effects. PMID:25942385
Fan, Rong; Emery, Travis; Zhang, Yongguo; Xia, Yuxuan; Sun, Jun; Wan, Jiandi
During cancer metastasis, circulating tumor cells constantly experience hemodynamic shear stress in the circulation. Cellular responses to shear stress including cell viability and proliferation thus play critical roles in cancer metastasis. Here, we developed a microfluidic approach to establish a circulatory microenvironment and studied circulating human colon cancer HCT116 cells in response to a variety of magnitude of shear stress and circulating time. Our results showed that cell viability decreased with the increase of circulating time, but increased with the magnitude of wall shear stress. Proliferation of cells survived from circulation could be maintained when physiologically relevant wall shear stresses were applied. High wall shear stress (60.5 dyne/cm2), however, led to decreased cell proliferation at long circulating time (1 h). We further showed that the expression levels of β-catenin and c-myc, proliferation regulators, were significantly enhanced by increasing wall shear stress. The presented study provides a new insight to the roles of circulatory shear stress in cellular responses of circulating tumor cells in a physiologically relevant model, and thus will be of interest for the study of cancer cell mechanosensing and cancer metastasis.
Fan, Rong; Emery, Travis; Zhang, Yongguo; Xia, Yuxuan; Sun, Jun; Wan, Jiandi
During cancer metastasis, circulating tumor cells constantly experience hemodynamic shear stress in the circulation. Cellular responses to shear stress including cell viability and proliferation thus play critical roles in cancer metastasis. Here, we developed a microfluidic approach to establish a circulatory microenvironment and studied circulating human colon cancer HCT116 cells in response to a variety of magnitude of shear stress and circulating time. Our results showed that cell viability decreased with the increase of circulating time, but increased with the magnitude of wall shear stress. Proliferation of cells survived from circulation could be maintained when physiologically relevant wall shear stresses were applied. High wall shear stress (60.5 dyne/cm2), however, led to decreased cell proliferation at long circulating time (1 h). We further showed that the expression levels of β-catenin and c-myc, proliferation regulators, were significantly enhanced by increasing wall shear stress. The presented study provides a new insight to the roles of circulatory shear stress in cellular responses of circulating tumor cells in a physiologically relevant model, and thus will be of interest for the study of cancer cell mechanosensing and cancer metastasis. PMID:27255403
Draskovic, R.J.; Bozanic, M.; Bozanic, V.; Bohus, T. (Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia))
Distribution of some elements (Cr, Fe, Co, Sb, Sc and Zn) in normal and pathologically altered human colon mucosa tissues were investigated by INAA. The following tissues were analyzed: normal colon mucosa, colitis chronica, colitis ulcerosa, adenoma tubulare and adenocarcinoma (diagnoses were previously confirmed clinically and histopathologically). The values of contents of the elements in these tissues (Csub(x) in nkg/g) are treated by specific computer functional programs. Regression functions of these parameters were found for the altered tissues in comparison to the normal, as well as specific functional correlations of the Csub(x)/Csub(y) relations for pairs of investigated elements. The functions which characterize these relations for the investigated colon mucosa tissue were also determined.
Full Text Available BACKGROUND: Chronic low-grade inflammation is recognized as an important factor contributing to senescence and age-related diseases. In mammals, levels of polyamines (PAs decrease during the ageing process; PAs are known to decrease systemic inflammation by inhibiting inflammatory cytokine synthesis in macrophages. Reductions in intestinal luminal PAs levels have been associated with intestinal barrier dysfunction. The probiotic strain Bifidobacterium animalis subsp. lactis LKM512 is known to increase intestinal luminal PA concentrations. METHODOLOGY/PRINCIPAL FINDINGS: We supplemented the diet of 10-month-old Crj:CD-1 female mice with LKM512 for 11 months, while the controls received no supplementation. Survival rates were compared using Kaplan-Meier survival curves. LKM512-treated mice survived significantly longer than controls (P<0.001; moreover, skin ulcers and tumors were more common in the control mice. We then analyzed inflammatory and intestinal conditions by measuring several markers using HPLC, ELISA, reverse transcription-quantitative PCR, and histological slices. LKM512 mice showed altered 16S rRNA gene expression of several predominant intestinal bacterial groups. The fecal concentrations of PAs, but not of short-chain fatty acids, were significantly higher in LKM512-treated mice (P<0.05. Colonic mucosal function was also better in LKM512 mice, with increased mucus secretion and better maintenance of tight junctions. Changes in gene expression levels were evaluated using the NimbleGen mouse DNA microarray. LKM512 administration also downregulated the expression of ageing-associated and inflammation-associated genes and gene expression levels in 21-month-old LKM512-treated mice resembled those in 10-month-old untreated (younger mice. CONCLUSION/SIGNIFICANCE: Our study demonstrated increased longevity in mice following probiotic treatment with LKM512, possibly due to the suppression of chronic low-grade inflammation in the colon
Nelson, T.A.; Holmes, S.; Alekseyenko, A.V.; Shenoy, M.; DeSantis, T.; Wu, C.H.; Andersen, G.L.; Winston, J.; Sonnenburg, J.; Pasricha, P.J.; Spormann, A.
Irritable bowel syndrome (IBS) is a chronic, episodic gastrointestinal disorder that is prevalent in a significant fraction of western human populations; and changes in the microbiota of the large bowel have been implicated in the pathology of the disease. Using a novel comprehensive, high-density DNA microarray (PhyloChip) we performed a phylogenetic analysis of the microbial community of the large bowel in a rat model in which intracolonic acetic acid in neonates was used to induce long lasting colonic hypersensitivity and decreased stool water content and frequency, representing the equivalent of human constipation-predominant IBS. Our results revealed a significantly increased compositional difference in the microbial communities in rats with neonatal irritation as compared with controls. Even more striking was the dramatic change in the ratio of Firmicutes relative to Bacteroidetes, where neonatally irritated rats were enriched more with Bacteroidetes and also contained a different composition of species within this phylum. Our study also revealed differences at the level of bacterial families and species. The PhyloChip is a useful and convenient method to study enteric microflora. Further, this rat model system may be a useful experimental platform to study the causes and consequences of changes in microbial community composition associated with IBS.
Malik, Ashish A.; Chowdhury, Somak; Schlager, Veronika; Oliver, Anna; Puissant, Jeremy; Vazquez, Perla G. M.; Jehmlich, Nico; von Bergen, Martin; Griffiths, Robert I.; Gleixner, Gerd
Despite several lines of observational evidence, there is a lack of consensus on whether higher fungal:bacterial (F:B) ratios directly cause higher soil carbon (C) storage. We employed RNA sequencing, protein profiling and isotope tracer techniques to evaluate whether differing F:B ratios are associated with differences in C storage. A mesocosm 13C labeled foliar litter decomposition experiment was performed in two soils that were similar in their physico-chemical properties but differed in microbial community structure, specifically their F:B ratio (determined by PLFA analyses, RNA sequencing and protein profiling; all three corroborating each other). Following litter addition, we observed a consistent increase in abundance of fungal phyla; and greater increases in the fungal dominated soil; implicating the role of fungi in litter decomposition. Litter derived 13C in respired CO2 was consistently lower, and residual 13C in bulk SOM was higher in high F:B soil demonstrating greater C storage potential in the F:B dominated soil. We conclude that in this soil system, the increased abundance of fungi in both soils and the altered C cycling patterns in the F:B dominated soils highlight the significant role of fungi in litter decomposition and indicate that F:B ratios are linked to higher C storage potential. PMID:27555839
Moustafa A El-Nakeeb
Full Text Available Several antihistaminics possess antibacterial activity against a broad spectrum of bacteria. However, the exact mechanism of such activity was unclear. Hence, the aim of this study is to investigate their mechanism of antibacterial activity especially their effect upon the permeability of the bacterial cytoplasmic membrane. The effects of azelastine, cetirizine, cyproheptadine and diphenhydramine were studied using Gram-positive and Gram-negative multiresistant clinical isolates. Leakage of 260 and 280 nm UV-absorbing materials was detected upon treatment with the tested antihistaminics; indicative of membrane alteration. Using an artificial membrane model, cholesterol-free negatively-charged unilamellar liposomes, confirmed the effect of antihistaminics upon the membrane permeability both by showing an apparent membrane damage as observed microscopically and by detection of leakage of preloaded dye from the liposomes colorimatrically. Moreover, examination of the ultrastructure of cells treated with azelastine and cetirizine under the transmission electron microscope substantiated the detected abnormalities in the cell wall and membrane. Furthermore, the effect of pretreating certain isolates for both short and long periods with selected antihistaminics was followed by the viable count technique. Increased vulnerability towards further exposure to azelastine was observed in cells pretreated with azelastine for 2 days and those pretreated with azelastine or cetrizine for 30 days.
Edith Graciela DIAZ; Carmen RODRIGUEZ de CASTRO; María MONTALTO de MECCA; José Alberto CASTRO
AIM: To study the effects of benznidazole (Bz), a drug used in the chemotherapy of the acute and the intermediate phase of Chagas' disease, on the colon of rats. METHODS: Sprague Dawley male rats received Bz 100 mg/kg ig. After 24 h colons were examined by electron microscopy. Concentrations of Bz in colonic tissue were measured by HPLC. Bz nitroreduction was followed by the decrease in the drug concentration using spectrophotometry and HPLC or by covalent binding to proteins of reactive products formed under in vivo and in vitro conditions. RESULTS: Colon mucosa of Bz-treated rats showed intense ultraslrucmral alterations: abundant mucus secretion at the level of the Goblet cells and dilatation of the endoplasmic reticulum and the Golgi apparatus in epithelial cells. The concentration of Bz in tissue was (59 ±18) and (93±14) nmoL/g (protein) 1 and 3 h after oral administration to rats, respectively. Colonic microsomes anaerobically activated Bz in the presence of NADPH. This activating nitroreductive pathway only involved a minor part of the total Bz and could not be detected spectrophotometrically or by HPLC analysis of the Bz consumed. Reactive metabolites that bound covalently to microsomal proteins were formed in this process.The covalent binding was also observed in vivo 1, 3, 6, and 24 h after administration of the labeled drug to rots. CONCLUSION: Reactive Bz metabolites produced during nitroreductive bioactivation of the drug in the colonic mucosa could interact with proteins and other cellular constituents to cause injury.
Full Text Available Abstract Background Switchgrass is one of the most promising bioenergy crop candidates for the US. It gives relatively high biomass yield and can grow on marginal lands. However, its yields vary from year to year and from location to location. Thus it is imperative to develop a low input and sustainable switchgrass feedstock production system. One of the most feasible ways to increase biomass yields is to harness benefits of microbial endophytes. Results We demonstrate that one of the most studied plant growth promoting bacterial endophytes, Burkholderia phytofirmans strain PsJN, is able to colonize and significantly promote growth of switchgrass cv. Alamo under in vitro, growth chamber, and greenhouse conditions. In several in vitro experiments, the average fresh weight of PsJN-inoculated plants was approximately 50% higher than non-inoculated plants. When one-month-old seedlings were grown in a growth chamber for 30 days, the PsJN-inoculated Alamo plants had significantly higher shoot and root biomass compared to controls. Biomass yield (dry weight averaged from five experiments was 54.1% higher in the inoculated treatment compared to non-inoculated control. Similar results were obtained in greenhouse experiments with transplants grown in 4-gallon pots for two months. The inoculated plants exhibited more early tillers and persistent growth vigor with 48.6% higher biomass than controls. We also found that PsJN could significantly promote growth of switchgrass cv. Alamo under sub-optimal conditions. However, PsJN-mediated growth promotion in switchgrass is genotype specific. Conclusions Our results show B. phytofirmans strain PsJN significantly promotes growth of switchgrass cv. Alamo under different conditions, especially in the early growth stages leading to enhanced production of tillers. This phenomenon may benefit switchgrass establishment in the first year. Moreover, PsJN significantly stimulated growth of switchgrass cv. Alamo under sub
Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia
Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction. PMID:26909087
Full Text Available Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants.The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%, Zn (86% and Cu (39% in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.
Kamdar, Karishma; Khakpour, Samira; Chen, Jingyu; Leone, Vanessa; Brulc, Jennifer; Mangatu, Thomas; Antonopoulos, Dionysios A.; Chang, Eugene B; Kahn, Stacy A.; Kirschner, Barbara S; Young, Glenn; DePaolo, R. William
Chronic inflammatory disorders are thought to arise due to an interplay between predisposing host genetics and environmental factors. For example, the onset of inflammatory bowel disease is associated with enteric proteobacterial infection, yet the mechanistic basis for this association is unclear. We have shown previously that genetic defiency in TLR1 promotes acute enteric infection by the proteobacteria Yersinia enterocolitica. Examining that model further, we uncovered an altered cellular immune response that promotes the recruitment of neutrophils which in turn increases metabolism of the respiratory electron acceptor tetrathionate by Yersinia. These events drive permanent alterations in anti-commensal immunity, microbiota composition, and chronic inflammation, which persist long after Yersinia clearence. Deletion of the bacterial genes involved in tetrathionate respiration or treatment using targeted probiotics could prevent microbiota alterations and inflammation. Thus, acute infection can drive long term immune and microbiota alterations leading to chronic inflammatory disease in genetically predisposed individuals.
Yinglong Su; Xiong Zheng; Yinguang Chen; Mu Li; Kun Liu
The increasing production and utilization of copper oxide nanoparticles (CuO NPs) result in the releases into the environment. However, the influence of CuO NPs on bacterial denitrification, one of the most important pathways to transform nitrate to dinitrogen in environment, has seldom been studied. Here we reported that CuO NPs caused a significant alteration of key protein expressions of a model denitrifier, Paracoccus denitrificans, leading to severe inhibition to denitrification. Total n...
Cécile Clavaud; Roland Jourdain; Avner Bar-Hen; Magali Tichit; Christiane Bouchier; Florence Pouradier; Charles El Rawadi; Jacques Guillot; Florence Ménard-Szczebara; Lionel Breton; Jean-Paul Latgé; Isabelle Mouyna
The bacterial and fungal communities associated with dandruff were investigated using culture-independent methodologies in the French subjects. The major bacterial and fungal species inhabiting the scalp subject's were identified by cloning and sequencing of the conserved ribosomal unit regions (16S for bacterial and 28S-ITS for fungal) and were further quantified by quantitative PCR. The two main bacterial species found on the scalp surface were Propionibacterium acnes and Staphylococcus epi...
PENG Jun-sheng; LIU Zhong-hui; LI Chu-jun; WU Xiao-bin; DIAO De-chang; DU Yan-ping; CHEN Jun-rong; LI Yun; WANG Hua-she
Background Techniques for the fast and accurate detection of bacterial infection are critical for early diagnosis, prevention and treatment of bacterial translocation in clinical severe acute pancreatitis (SAP). In this study, the availability of a real-time PCR method in detection of bacterial colonization in SAP rat models was investigated.Methods Samples of blood, mesenteric lymph nodes (MLN), pancreas and liver from 24 specific pathogen-free rats (8 in a control group, 16 in a SAP group) were detected for bacterial infection rates both by agar plate culture and a real-time PCR method, and the results were made contrast.Results Bacterial infection rates of the blood, MLN, pancreas and liver in the SAP group and the control group by the two different methods were almost the same, which were 5/16, 12/16, 15/16, 12/16 in the SAP group compared with 0/8, 1/8, 0/8, 0/8 in the control group by agar plate culture, while 5/16, 10/16, 13/16, 12/16 and 0/8, 1/8, 0/8, 0/8 respectively by a real-time PCR method. Bacterial number was estimated by real-time PCR, which showed that in the same mass of tissues, the pancreas contained more bacteria than the other three kinds of organs in SAP rats (P <0.01), that may be due to the edema, necrosis and hemorrhage existing in the pancreas, making it easier for bacteria to invade and breed.Conclusion Fast and accurate detection of bacterial translocation in SAP rat models could be carried out by a real-time PCR procedure.
Mortazavi, Seyed Mohammad Javad; Darvish, Leili; Abounajmi, Mohammad; Zarei, Samira; Zare, Tahereh; Taheri, Mohammad; Nematollahi, Samaneh
Background Many pathogenic bacteria show different levels of antibiotic resistance. Furthermore, a lot of hospital-acquired infections are caused by highly resistant or multidrug-resistant Gram-negative bacteria. According to WHO, patients with drug-resistant infections have higher morbidity and mortality. Moreover, patients infected with bacteria that are resistant to antibiotics considerably consume more healthcare resources. Objectives In this study, we explored a physical method of converting drug-resistant bacteria to drug-sensitive ones. Materials and Methods This is an in vitro case-control study, performed at the Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences (SUMS), Shiraz, Iran in 2014. All experiments were carried out using Gram-negative bacteria Klebsiella pneumonia and E. coli and Gram-positive Staphylococcus aureus and Streptococcus group A, isolated from hospitalized patients. The bacterial strains were obtained from the Persian Type Culture Collection, IROST, Iran (Klebsiella pneumonia PTCC 1290) and Bacteriology Department of Shahid Faghihi Teaching Hospital, Shiraz, Iran (E. coli, Staphylococcus aureus, and Streptococcus group A). The bacteria in culture plates were exposed to diagnostic ultrasound using a MyLab70XVG sonography system for 5 minutes. Then, the bacteria were cultured on Mueller-Hinton agar and incubated at 35°C for 18 hours. Finally, antibiotic susceptibility test was performed and the inhibition zone in both control and exposed groups were measured. Three replicate agar plates were used for each test and the inhibition zones of the plates were recorded. Results Compared with the results obtained from unexposed bacteria, statistically significant variations of sensitivity to antibiotics were found in some strains after short-term exposure. In particular, we found major differences (making antibiotic-resistant bacteria susceptible or vice versa) in the diameters of
The soluble metals of the pollutant, residual oil fly ash (ROFA), have been shown to alter pulmonary bacterial clearance in rats. The goal of this study was to determine the potential effects on both the innate and adaptive lung immune responses after bacterial infection in rats pre-exposed to the soluble metals in ROFA. Sprague-Dawley rats were intratracheally dosed (i.t.) at day 0 with ROFA (R-Total) (1.0 mg/100 g body weight), the soluble fraction of ROFA (R-Soluble), the soluble sample subject to a chelator (R-Chelex), or phosphate-buffered saline (Saline). On day 3, rats were administered an i.t. dose of 5 x 104 Listeria monocytogenes. On days 6, 8, and 10, bacterial pulmonary clearance was monitored and bronchoalveolar lavage (BAL) was performed on days 3 (pre-infection), 6, 8, and 10. A concentrated first fraction of lavage fluid was retained for analysis of lactate dehydrogenase and albumin to assess lung injury. BAL cell number, phenotype, and production of reactive oxygen (ROS) and nitrogen species (RNS) were assessed, and a variety of cytokines were measured in the BAL fluid. Rats pre-treated with R-Soluble showed elevated lung injury/cytotoxicity and increased cellular influx into the lungs. R-Soluble-treatment also altered ROS, RNS, and cytokine levels, and caused a degree of macrophage and T cell inhibition. These effects of R-Soluble result in increased pulmonary bacterial burden after infection. The results suggest that soluble metals in ROFA increase lung injury and inflammation, and alter both innate and adaptive pulmonary immune responses
Guirro, Elaine Caldeira de Oliveira; Angelis, Dejanira de Franceschi de; Sousa, Natanael Teixeira Alves de; Guirro, Rinaldo Roberto de Jesus
Staphylococcus aureus and Escherichia coli are among the major bacterial species that colonize skin ulcers. Therapeutic ultrasound (TUS) produces biophysical effects that are relevant to wound healing; however, its application over a contaminated injury is not evidence-based. The objective of this research was to analyze the effect of TUS on in vitro-isolated S. aureus and E. coli, including the combination of ultrasound and antibiotics, in order to assess their antibiotic action on bacterial susceptibility. For the experiments, the bacterial strains were suspended in saline, then diluted (10(4)CFU/mL) for irradiation (at 1 and 3MHz, 0.5 and 0.8W/cm(2) for 0 and 15min) and the combination treatment of ultrasonication and antibiotics was administered by adding nalidixic acid (S. aureus) and tetracycline (E. coli) at concentrations equivalent to 50% of the minimum inhibitory concentration (MIC). The experiments were carried out in duplicate with six repetitions. The suspensions were inoculated on to Petri plates and incubated at 37°C and the colony forming units (CFUs) were counted after 24h. The results were subjected to the Shapiro-Wilk normality test, followed by parametric ANOVA and Tukey's post hoc test at a significance level of 1%. The results demonstrated that the action of TUS at 1MHz inhibited bacterial growth while at 3MHz, bacterial growth was observed in both species. However, the synergistic combination of ultrasound and antibiotics was able to inhibit the growth of both bacteria completely after 15min of ultrasonication. The results suggest that the action of ultrasound on S. aureus and E. coli are dependent on the oscillation frequency as well as the intensity and time of application. The combination of ultrasound with antibiotics was able to inhibit bacterial growth fully at all frequencies and doses in both species. PMID:27150772
Francisco Edilson Leite Pinto Júnior
Full Text Available PURPOSE: To investigate whether the alterations of the diverted colon segment mucosa, evidenced in fecal colitis, would be able to alter Bacterial Translocation (BT. METHODS: Sixty-two Wistar male rats ranging from 220 to 320 grams of weight, were divided in two groups: A (Colostomy and B (Control, with 31 animals each one. In group A, all animals underwent end colostomy, one stoma, in ascending colon; and in the 70th POD was injected in five rats, by rectal route diverted segment - 2ml of a 0.9% saline solution in animals (A1 subgroup; in eight it was inoculated, by rectal route, 2ml of a solution containing Escherichia coli ATCC 25922 (American Type Culture Collection, in a concentration of 10(8 Colony Forming Unit for milliliters (CFU/ml - A2 Subgroup; in ten animals the same solution of E. coli was inoculated, in a concentration of 10(11 CFU/ml (A3 Subgroup; and in eight it was collected part of the mucus found in the diverted distal colonic segment for neutral sugars and total proteins dosage (A4 subgroup. The animals from the group B underwent the same procedures of group A, but with differences in the colostomy confection. In rats from subgroups A1, A2, A3, B1, B2, and B3 2ml of blood were aspirated from the heart, and fragments from mesenteric lymphatic nodule, liver, spleen, lung and kidney taken for microbiological analysis, after their death. This analysis consisted of evidencing the presence of E. coli ATCC 25922 CFU. Mann-Whitney and ANOVA Tests were applied as analytic techniques for association of variables. RESULTS: The occurrence of BT was evidenced only in those animals in which inoculated concentration of E. coli ATCC 25922, reached levels of 10(11CFU/ml, i.e. in Subgroups A3 and B3, although, being significantly greater (80% in those animals without colostomy (subgroup B3 when compared to the ones with colostomy (20% from the subgroup A3 (P OBJETIVO: Investigar se as alterações do cólon desfuncionalizado, evidenciadas na
Carol L Fischer; Katherine S Walters; David R Drake; Deborah V Dawson; Derek R Blanchette; Kim A Brogden; Philip W Wertz
Oral mucosal and salivary lipids exhibit potent antimicrobial activity for a variety of Gram-positive and Gram-negative bacteria;however, little is known about their spectrum of antimicrobial activity or mechanisms of action against oral bacteria. In this study, we examine the activity of two fatty acids and three sphingoid bases against Porphyromonas gingivalis, an important colonizer of the oral cavity implicated in periodontitis. Minimal inhibitory concentrations, minimal bactericidal concentrations, and kill kinetics revealed variable, but potent, activity of oral mucosal and salivary lipids against P. gingivalis, indicating that lipid structure may be an important determinant in lipid mechanisms of activity against bacteria, although specific components of bacterial membranes are also likely important. Electron micrographs showed ultrastructural damage induced by sapienic acid and phytosphingosine and confirmed disruption of the bacterial plasma membrane. This information, coupled with the association of treatment lipids with P. gingivalis lipids revealed via thin layer chromatography, suggests that the plasma membrane is a likely target of lipid antibacterial activity. Utilizing a combination of two-dimensional in-gel electrophoresis and Western blot followed by mass spectroscopy and N-terminus degradation sequencing we also show that treatment with sapienic acid induces upregulation of a set of proteins comprising a unique P. gingivalis stress response, including proteins important in fatty acid biosynthesis, metabolism and energy production, protein processing, cell adhesion and virulence. Prophylactic or therapeutic lipid treatments may be beneficial for intervention of infection by supplementing the natural immune function of endogenous lipids on mucosal surfaces.
Andriamihaja, Mireille; Lan, Annaig; Beaumont, Martin; Audebert, Marc; Wong, Ximena; Yamada, Kana; Yin, Yulong; Tomé, Daniel; Carrasco Pozo, Catalina; Gotteland, Martin; Kong, Xiangfeng
p-Cresol that is produced by the intestinal microbiota horn the amino acid tyrosine is found at millimolar concentrations in the human feces. The effects of this metabolite On colonic epithelial cells were tested in this study. Using the human colonic epithelial HT-29 Glc(-/+) cell line, we found that 0.8 mM p-cresol inhibits cell proliferation, an effect concomitant with an accumulation of the cells in the 5 phase and with a slight increase of cell detachment without necrotic effect. At this...
Turlapati, Swathi A; Minocha, Rakesh; Bhiravarasa, Premsai S; Tisa, Louis S; Thomas, William K; Minocha, Subhash C
At the Harvard Forest, Petersham, MA, the impact of 20 years of annual ammonium nitrate application to the mixed hardwood stand on soil bacterial communities was studied using 16S rRNA genes pyrosequencing. Amplification of 16S rRNA genes was done using DNA extracted from 30 soil samples (three treatments × two horizons × five subplots) collected from untreated (control), low N-amended (50 kg ha(-1) year(-1)) and high N-amended (150 kg ha(-1) year(-1)) plots. A total of 1.3 million sequences were processed using qiime. Although Acidobacteria represented the most abundant phylum based on the number of sequences, Proteobacteria were the most diverse in terms of operational taxonomic units (OTUs). UniFrac analyses revealed that the bacterial communities differed significantly among soil horizons and treatments. Microsite variability among the five subplots was also evident. Nonmetric multidimensional scaling ordination of normalized OTU data followed by permutational manova further confirmed these observations. Richness indicators and indicator species analyses revealed higher bacterial diversity associated with N amendment. Differences in bacterial diversity and community composition associated with the N treatments were also observed at lower phylogenetic levels. Only 28-35% of the 6 936 total OTUs identified were common to three treatments, while the rest were specific to one treatment or common to two. PMID:22974374
Richter, Jan F; Pieper, Robert; Zakrzewski, Silke S; Günzel, Dorothee; Schulzke, Joerg D; Van Kessel, Andrew G
Protein fermentation end products may damage the colonic mucosa, which could be counteracted by dietary inclusion of fermentable carbohydrates (fCHO). Although fermentable crude protein (fCP) and fCHO are known to affect microbial ecology, their interactive effects on epithelial barrier function are unknown. In the present study, in a 2 × 2 factorial experiment, thirty-two weaned piglets were fed low-fCP/low-fCHO (14·5 % crude protein (CP)/14·5 % total dietary fibre (TDF)), low-fCP/high-fCHO (14·8 % CP/16·6 % TDF), high-fCP/low-fCHO (19·8 % CP/14·5 % TDF) and high-fCP/high-fCHO (20·1 % CP/18·0 % TDF) diets. After 21-23 d, samples of proximal and distal colonic mucosae were investigated in Ussing chambers with respect to the paracellular and transcytotic passages of macromolecules and epithelial ion transport. The high-fCHO diets were found to reduce the permeability of the distal colon to the transcytotic marker horseradish peroxidase (HRP, 44 kDa; P <0·05) and also reduce the paracellular permeation of N-hydroxysuccinimide-biotin into the submucosa (443 Da; P <0·05), whereas that of HRP was decreased by the high-fCP diets (P <0·01). Short-circuit current (active ion transport), transepithelial resistance (barrier function) and charge selectivity were largely unaffected in both the segments. However, the high-fCP diets were found to suppress the aldosterone-induced epithelial Na channel activity (P <0·01) irrespective of fCHO inclusion. The high-fCP diets generally reduced the expression of colonic claudin-1, claudin-2 and claudin-3 (P <0·01), while that of claudin-4 was increased by the high-fCHO diets (P <0·01). The high-fCHO diets also altered the ratio between occludin forms (P <0·05) and increased the expression of tricellulin in the proximal colon, which was not observed with high-fCP diets. In conclusion, dietary fCHO and fCP exerted few and largely independent effects on functional measurements, but altered tight junction
Stokholm, J.; Schjørring, S.; Eskildsen, Carl Emil Aae;
Antibiotics may induce alterations in the commensal microbiota of the birth canal in pregnant women. Therefore, we studied the effect of antibiotic administration during pregnancy on commensal vaginal bacterial colonization at gestational week 36. Six hundred and sixty-eight pregnant women from the...... significant changes in vaginal Streptococcus agalactiae (group B streptoccocus) or Staphylococcus aureus colonization following antibiotic treatment in pregnancy. Antibiotic administration during pregnancy leads to alterations in the vaginal microbiological ecology prior to birth, with potential morbidity......, and long-term effects on the early microbial colonization of the neonate....
Full Text Available The bacterial and fungal communities associated with dandruff were investigated using culture-independent methodologies in the French subjects. The major bacterial and fungal species inhabiting the scalp subject's were identified by cloning and sequencing of the conserved ribosomal unit regions (16S for bacterial and 28S-ITS for fungal and were further quantified by quantitative PCR. The two main bacterial species found on the scalp surface were Propionibacterium acnes and Staphylococcus epidermidis, while Malassezia restricta was the main fungal inhabitant. Dandruff was correlated with a higher incidence of M. restricta and S. epidermidis and a lower incidence of P. acnes compared to the control population (p<0.05. These results suggested for the first time using molecular methods, that dandruff is linked to the balance between bacteria and fungi of the host scalp surface.
Wang, Jichen; Xue, Chao; Song, Yang; Wang, Lei; Huang, Qiwei; Shen, Qirong
Maintaining soil fertility and the microbial communities that determine fertility is critical to sustainable agricultural strategies, and the use of different organic fertilizer (OF) regimes represents an important practice in attempts to preserve soil quality. However, little is known about the dynamic response of bacterial communities to fertilization regimes across crop growth stages. In this study, we examined microbial community structure and diversity across eight representative growth stages of wheat-rice rotation under four different fertilization treatments: no nitrogen fertilizer (NNF), chemical fertilizer (CF), organic–inorganic mixed fertilizer (OIMF), and OF. Quantitative PCR (QPCR) and high-throughput sequencing of bacterial 16S rRNA gene fragments revealed that growth stage as the best predictor of bacterial community abundance and structure. Additionally, bacterial community compositions differed between wheat and rice rotations. Relative to soils under wheat rotation, soils under rice rotation contained higher relative abundances (RA) of anaerobic and mesophilic microbes and lower RA of aerophilic microbes. With respect to fertilization regime, NNF plots had a higher abundance of nitrogen–fixing Cyanobacteria. OIMF had a lower abundance of ammonia-oxidizing Thaumarchaeota compared with CF. Application of chemical fertilizers (CF and OIMF treatments) significantly increased the abundance of some generally oligotrophic bacteria such those belonging to the Acidobacteria, while more copiotrophic of the phylum Proteobacteria increased with OF application. A high correlation coefficient was found when comparing RA of Acidobacteria based upon QPCR vs. sequence analysis, yet poor correlations were found for the α- and β- Proteobacteria, highlighting the caution required when interpreting these molecular data. In total, crop, fertilization scheme and plant developmental stage all influenced soil microbial community structure, but not total levels of
Guo-Dong Qin; Ming-Zhao Xiao; Yuan-Da Zhou; Jing Yang; Hai-Xia He; Yue He; Yang Zeng
The combination of levofloxacin and α1 adrenergic antagonist treatment is the current preferred choice for both bacterial and non-bacterial prostatitis.The aim of this study is to explore the influence of α1 adrenergic antagonists on the pharmacokinetics of levofloxacin using rat models with acute bacterial prostatitis (ABP) induced by direct injection with Escherichia coli(ATCC25922).A total of 96 model rats were randomly assigned into two groups:the experimental group (treated with both tamsulosin and levofloxacin,n=48) and the control group (treated with levofloxacin and solvents,n=48).Six rats from each group were euthanized to collect blood,liver,kidney and prostate samples at the time points of 0.125,0.25,0.5,1,2,4,8 and 12 h after drug administration.The levofloxacin concentrations were detected by high performance liquid chromatography (HPLC),and the pharmacokinetic parameters were calculated using the 3p97 software program.There were no obvious differences (P＞0.05) between the experimental and control groups in the major pharmacokinetic parameters of levofloxacin,including the halftime (t1/2),time to peak (tpeak),clearance rate (CL),maximum concentration (Cmax) and area under the curve (AUC0～12),in the plasma or in the hepatic and kidney tissues of the model rats.However,in the prostatic tissues,tamsulosin increased the Cmax,prolonged the t1/2 and decreased the CL of levofloxacin (P＜0.05).These results indicate that tamsulosin may enhance the effect of levofloxacin in the treatment of bacterial prostatitis without changing the drug concentration in the liver and kidney.
Producción endógena de alcohol en pacientes con cirrosis hepática, alteración motora y sobrecrecimiento bacteriano Endogenous ethanol production, alterations in gastrointestinal motility and bacterial overgrowth and cirrhosis
Ana María Madrid S; Carmen Hurtado H; Sara Gatica I; Inelia Chacón B; Ana Toyos D; Carlos Defilippi C
Background: Small intestinal bacterial overgrowth generates endogenous ethanol production both in experimental animals and humans. Patients with cirrhosis have small intestinal bacterial overgrowth, but endogenous ethanol production has not been studied in them. Aim: To investigate endogenou ethanol production in patients with cirrhosis, altered intestinal motility and small intestinal bacterial overgrowth. Patients and methods: Eight patients with cirrhosis of different etiologies and altere...
Podolsky, D K; Madara, J L; King, N; Sehgal, P; Moore, R; Winter, H S
Heterogeneity of colonic mucin glycoprotein was examined in rectal mucosal biopsy specimens from a variety of primate species (Saguinus oedipus, n = 18; Macaca mulatta, n = 2; Macaca fascicularis, n = 2; Aotus trivirgatus, n = 2; Saimiri sciureus, n = 2; and Callithrix jacchus, n = 2). After initial separation of radiolabeled mucin and nonmucin glycoproteins solubilized from mucosal biopsy specimens, at least five labeled mucin components were found in monkey rectal mucosa in contrast to the six mucin fractions observed in the human colon. Although primates consistently lacked the earliest eluting component present in human colonic mucin, other mucin components cochromatographed with comparable fractions previously identified in human colonic biopsy specimens. The relative proportions of each fraction were consistent throughout all species except the cotton-top tamarin (S. oedipus), an animal that develops a chronic colitis. The cotton-top tamarin was found to have a markedly reduced amount of one mucin component (IV) in a manner analogous to the reduction in a human mucin fraction previously noted in patients with ulcerative colitis. Sequential evaluation of mucin profiles in cotton-top tamarins (n = 12) treated with sulfasalazine (50 mg/kg X day) or placebo in a 10-wk double-blind crossover study demonstrated the persistence of the selective reduction in tamarin species IV unrelated to disease activity. In contrast, the relative amount of tamarin mucin III was greater in association with increased disease activity than that observed in association with reduced disease activity (46% +/- 11% total mucin vs. 19% +/- 7% total mucin posttreatment). PMID:3917260
Raghavan, Chellan Vijaya; Muthulingam, Chithambaram; Jenita, Joseph Amaladoss Josephine Leno; Ravi, Thengungal Kochupapy
The colon specific drug delivery systems based on polysaccharides; locust bean gum and chitosan in the ratio of 2 : 3, 3 : 2 and 4 : 1 were evaluated using in vitro and in vivo methods. The in vitro studies in pH 6.8 phosphate buffer containing 2% w/v rat caecal contents showed that the cumulative percentage release of mesalazine after 26 h were 31.25+/-0.56, 46.25+/-0.96, 97.5+/-0.26 (mean+/-S.D.), respectively. The in vivo studies conducted in nine healthy male human volunteers for the various formulations revealed that, the drug release was initiated only after 5 h (i.e.) transit time of small intestine and the bioavailability (AUC(0-->t*)) of the drug was found to be 85.24+/-0.10, 196.08+/-0.12, 498.62+/-0.10 microg x h/ml 26 (mean+/-S.D.), respectively. These studies on the polysaccharides demonstrated that the combination of locust bean gum and chitosan as a coating material proved capable of protecting the core tablet containing mesalazine during the condition mimicking mouth to colon transit. In particular, the formulation containing locust bean gum and chitosan in the ratio of 4 : 1 held a better dissolution profile, higher bioavailability and hence a potential carrier for drug targeting to colon. PMID:12130845
Full Text Available Crohn's disease (CD is notably characterized by the expansion of visceral fat with small adipocytes expressing a high proportion of anti-inflammatory genes. Conversely, visceral fat depots in ulcerative colitis (UC patients have never been characterized. Our study aims were a to compare adipocyte morphology and gene expression profile and bacterial translocation in omental (OM and mesenteric (MES adipose tissue of patients with UC and CD, and b to investigate the effect of bacterial infection on adipocyte proliferation in vitro. Specimens of OM and MES were collected from 11 UC and 11 CD patients, processed and examined by light microscopy. Gene expression profiles were evaluated in adipocytes isolated from visceral adipose tissue using microarray and RTqPCR validations. Bacteria within adipose tissue were immuno-detected by confocal scanning laser microscopy. Adipocytes were incubated with Enterococcus faecalis and cells counted after 24 h. Morphology and molecular profile of OM and MES revealed that UC adipose tissue is less inflamed than CD adipose tissue. Genes linked to inflammation, bacterial response, chemotaxis and angiogenesis were down-regulated in adipocytes from UC compared to CD, whereas genes related to metallothioneins, apoptosis pathways and growth factor binding were up-regulated. A dense perinuclear positivity for Enterococcus faecalis was detected in visceral adipocytes from CD, whereas positivity was weak in UC. In vitro bacterial infection was associated with a five-fold increase in the proliferation rate of OM preadipocytes. Compared to UC, visceral adipose tissue from CD is more inflamed and more colonized by intestinal bacteria, which increase adipocyte proliferation. The influence of bacteria stored within adipocytes on the clinical course of IBD warrants further investigations.
Joo, Hwang-Soo; Fu, Chih-Iung; Otto, Michael
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160595
Hofmanová, Jiřina; Ciganek, M.; Slavík, J.; Kozubík, Alois; Stixová, Lenka; Vaculová, Alena; Dušek, L.; Machala, M.
Roč. 23, č. 6 (2012), s. 539-548. ISSN 0955-2863 R&D Projects: GA ČR(CZ) GA524/07/1178; GA ČR(CZ) GAP301/11/1730 Institutional research plan: CEZ:AV0Z50040507 Institutional support: RVO:68081707 Keywords : Colon cancer * Polyunsaturated fatty acids * Butyrate Subject RIV: BO - Biophysics Impact factor: 4.552, year: 2012
Leser, Thomas D.; Lindecrona, Rikke Hvid; Jensen, Tim Kåre;
Bacterial communities in the large intestines of pigs were compared using terminal restriction fragment length polymorphism (T-RFLP) analysis targeting the 16S ribosomal DNA. The pigs were fed different experimental diets based on either modified standard feed or cooked rice supplemented with...
Leser, Thomas D.; Lindecrona, Rikke Hvid; Jensen, Tim Kåre; Jensen, Bent B.; Møller, Kristian
Bacterial communities in the large intestines of pigs were compared using terminal restriction fragment length polymorphism (T-RFLP) analysis targeting the 16S ribosomal DNA. The pigs were fed different experimental diets based on either modified standard feed or cooked rice supplemented with die...
Depan, D.; Misra, R.D.K., E-mail: email@example.com
Silicone-based biomedical devices are prone to microbial adhesion, which is the primary cause of concern in the functioning of the artificial device. Silicone exhibiting long-term and effective antibacterial ability is highly desirable to prevent implant related infections. In this regard, nanophase titania was incorporated in silicone as an integral part of the silicone network structure through cross-link mechanism, with the objective to reduce bacterial adhesion to a minimum. The bacterial adhesion was studied using crystal violet assay, while the mechanism of inhibition of biofilm formation was studied via electron microscopy. The incorporation of nanophase titania in silicone dramatically reduced the viability of Staphylococcus aureus (S. aureus) and the capability to adhere on the surface of hybrid silicone by ∼ 93% in relation to stand alone silicone. The conclusion of dramatic reduction in the viability of S. aureus is corroborated by different experimental approaches including biofilm inhibition assay, zone of inhibition, and through a novel experiment that involved incubation of biofilm with titania nanoparticles. It is proposed that the mechanism of disruption of bacterial film in the presence of titania involves puncturing of the bacterial cell membrane. - Highlights: • Network structure titania in silicone imparts antimicrobial activity. • Ability to microbial adhesion is significantly reduced. • Antimicrobial mechanism involves rupture of biofilm.
Silicone-based biomedical devices are prone to microbial adhesion, which is the primary cause of concern in the functioning of the artificial device. Silicone exhibiting long-term and effective antibacterial ability is highly desirable to prevent implant related infections. In this regard, nanophase titania was incorporated in silicone as an integral part of the silicone network structure through cross-link mechanism, with the objective to reduce bacterial adhesion to a minimum. The bacterial adhesion was studied using crystal violet assay, while the mechanism of inhibition of biofilm formation was studied via electron microscopy. The incorporation of nanophase titania in silicone dramatically reduced the viability of Staphylococcus aureus (S. aureus) and the capability to adhere on the surface of hybrid silicone by ∼ 93% in relation to stand alone silicone. The conclusion of dramatic reduction in the viability of S. aureus is corroborated by different experimental approaches including biofilm inhibition assay, zone of inhibition, and through a novel experiment that involved incubation of biofilm with titania nanoparticles. It is proposed that the mechanism of disruption of bacterial film in the presence of titania involves puncturing of the bacterial cell membrane. - Highlights: • Network structure titania in silicone imparts antimicrobial activity. • Ability to microbial adhesion is significantly reduced. • Antimicrobial mechanism involves rupture of biofilm
Wilson, J. W.; Ott, C. M.; zuBentrup, K. Honer; Ramamurthy R.; Quick, L.; Porwollik, S.; Cheng, P.; McClellan, M.; Tsaprailis, G.; Radabaugh, T.; Hunt, A.; Fernandez, D.; Richter, E.; Shah, M.; Kilcoyne, M.; Joshi, L.; Nelman-Gonzalez, M.; Hing, S.; Parra, M.; Dumaras, P.; Norwood, K.; Nickerson, C. A.; Bober, R.; Devich, J.; Ruggles, A.
A comprehensive analysis of both the molecular genetic and phenotypic responses of any organism to the spaceflight environment has never been accomplished due to significant technological and logistical hurdles. Moreover, the effects of spaceflight on microbial pathogenicity and associated infectious disease risks have not been studied. The bacterial pathogen Salmonella typhimurium was grown aboard Space Shuttle mission STS-115 and compared to identical ground control cultures. Global microarray and proteomic analyses revealed 167 transcripts and 73 proteins changed expression with the conserved RNA-binding protein Hfq identified as a likely global regulator involved in the response to this environment. Hfq involvement was confirmed with a ground based microgravity culture model. Spaceflight samples exhibited enhanced virulence in a murine infection model and extracellular matrix accumulation consistent with a biofilm. Strategies to target Hfq and related regulators could potentially decrease infectious disease risks during spaceflight missions and provide novel therapeutic options on Earth.
Full Text Available Abstract Background Staphylococcus aureus releases virulence factors (VF that may impair the innate protective functions of airway cells. The aim of this study was to determine whether a long-acting β2 adrenergic receptor agonist (salmeterol hydroxynaphthoate, Sal combined with a corticosteroid (fluticasone propionate, FP was able to regulate ion content and cytokine expression by airway glandular cells after exposure to S. aureus supernatant. Methods A human airway glandular cell line was incubated with S. aureus supernatant for 1 h and then treated with the combination Sal/FP for 4 h. The expression of actin and CFTR proteins was analyzed by immunofluorescence. Videomicroscopy was used to evaluate chloride secretion and X-ray microanalysis to measure the intracellular ion and water content. The pro-inflammatory cytokine expression was assessed by RT-PCR and ELISA. Results When the cells were incubated with S. aureus supernatant and then with Sal/FP, the cellular localisation of CFTR was apical compared to the cytoplasmic localisation in cells incubated with S. aureus supernatant alone. The incubation of airway epithelial cells with S. aureus supernatant reduced by 66% the chloride efflux that was fully restored by Sal/FP treatment. We also observed that Sal/FP treatment induced the restoration of ion (Cl and S and water content within the intracellular secretory granules of airway glandular cells and reduced the bacterial supernatant-dependent increase of pro-inflammatory cytokines IL8 and TNFα. Conclusions Our results demonstrate that treatment with the combination of a corticosteroid and a long-acting β2 adrenergic receptor agonist after bacterial infection restores the airway glandular cell function. Abnormal mucus induced by defective ion transport during pulmonary infection could benefit from treatment with a combination of β2 adrenergic receptor agonist and glucocorticoid.
Bakiah Shabamddin; K Wei Chan; Siti Suraiya Mohd Noor; Zunaina Embong
AIM:To determine the rate of bacterial colonization in hydrogel disposable contact lenses and solutions and to identify the contaminating organisms.METHODS:A cross sectional study with purposive sampling was carried out.One hundred hydrogel contact lenses were collected from wearers among undergraduate students of Health Campus,University Sains Malaysia.All lenses and storage solutions were sent for microbiological culture and gram staining.RESULTS:The majority of study participants were females(98%).The mean age was 21.36±1.63 years.Forty-one subject participants(82%)showed positive bacterial colonization of the lenses.From storage solutions 32% yielded positive colonization by bacteria.The most common organisms were coagulase negative staphyJococcus,Staph aureus and streptococci while Pseudomonas sp.and Serratia sp.were isolated more frequently from contact lenses.CONCLUSION:Contact lens wearing is potentially dangerous as a result of high rate of bacterial colonization of the lenses and its storage solutions.Extreme precaution and adherence to strict hygienic practice is recommended during lens handling and wearing.%目的:确定抛弃型水凝胶接触镜及其护理液细菌定植的比率,并确定污染的病原体.方法:按目的抽样进行横断面研究.从马来西亚Sains大学健康校园的本科学生接触镜配戴者中收集100片水凝胶接触镜.所有的镜片和护理液均送微生物培养和革兰氏染色.结果:大多数的研究参与者为女性(98%).平均年龄21.36±1.63岁.41片接触镜(82%)呈现阳性细菌定植,32%的护理液可见阳性细菌定植.最常见的病原体是凝固酶阴性葡萄球菌、金黄色葡萄球菌和链球菌,而在接触镜中能更频繁地分离出假单胞菌和沙雷氏菌.结论:配戴接触镜有导致镜片和护理液细菌定植的潜在危险.建议在镜片护理和配戴过程中采取最大程度的预防措施并严格遵守卫生做法.
Su, Yinglong; Zheng, Xiong; Chen, Yinguang; Li, Mu; Liu, Kun
The increasing production and utilization of copper oxide nanoparticles (CuO NPs) result in the releases into the environment. However, the influence of CuO NPs on bacterial denitrification, one of the most important pathways to transform nitrate to dinitrogen in environment, has seldom been studied. Here we reported that CuO NPs caused a significant alteration of key protein expressions of a model denitrifier, Paracoccus denitrificans, leading to severe inhibition to denitrification. Total nitrogen removal efficiency was decreased from 98.3% to 62.1% with the increase of CuO NPs from 0.05 to 0.25 mg/L. Cellular morphology and integrity studies indicated that nanoparticles entered the cells. The proteomic bioinformatics analysis showed that CuO NPs caused regulation of proteins involved in nitrogen metabolism, electron transfer and substance transport. The down-regulation of GtsB protein (responsible for glucose transport) decreased the production of NADH (electron donor for denitrification). Also, the expressions of key electron-transfer proteins (including NADH dehydrogenase and cytochrome) were suppressed by CuO NPs, which adversely affected electrons transfer for denitrification. Further investigation revealed that CuO NPs significantly inhibited the expressions and catalytic activities of nitrate reductase and nitrite reductase. These results provided a fundamental understanding of the negative influences of CuO NPs on bacterial denitrification.
Colorectal cancer; Cancer - colon; Rectal cancer; Cancer - rectum; Adenocarcinoma - colon; Colon - adenocarcinoma ... often lead to a complete cure. Almost all colon cancers start in the lining of the colon and ...
Esposito, Alfonso; Ciccazzo, Sonia; Borruso, Luigimaria; Zerbe, Stefan; Daffonchio, Daniele; Brusetti, Lorenzo
Alpha and beta diversities of the bacterial communities growing on rock surfaces, proto-soils, riparian sediments, lichen thalli, and water springs biofilms in a glacier foreland were studied. We used three molecular based techniques to allow a deeper investigation at different taxonomic resolutions: denaturing gradient gel electrophoresis, length heterogeneity-PCR, and automated ribosomal intergenic spacer analysis. Bacterial communities were mainly composed of Acidobacteria, Proteobacteria, and Cyanobacteria with distinct variations among sites. Proteobacteria were more represented in sediments, biofilms, and lichens; Acidobacteria were mostly found in proto-soils; and Cyanobacteria on rocks. Firmicutes and Bacteroidetes were mainly found in biofilms. UniFrac P values confirmed a significant difference among different matrices. Significant differences (P < 0.001) in beta diversity were observed among the different matrices at the genus-species level, except for lichens and rocks which shared a more similar community structure, while at deep taxonomic resolution two distinct bacterial communities between lichens and rocks were found. PMID:23712376
Mo, Charlie Y; Manning, Sara A; Roggiani, Manuela; Culyba, Matthew J; Samuels, Amanda N; Sniegowski, Paul D; Goulian, Mark; Kohli, Rahul M
The bacterial SOS response is a DNA damage repair network that is strongly implicated in both survival and acquired drug resistance under antimicrobial stress. The two SOS regulators, LexA and RecA, have therefore emerged as potential targets for adjuvant therapies aimed at combating resistance, although many open questions remain. For example, it is not well understood whether SOS hyperactivation is a viable therapeutic approach or whether LexA or RecA is a better target. Furthermore, it is important to determine which antimicrobials could serve as the best treatment partners with SOS-targeting adjuvants. Here we derived Escherichia coli strains that have mutations in either lexA or recA genes in order to cover the full spectrum of possible SOS activity levels. We then systematically analyzed a wide range of antimicrobials by comparing the mean inhibitory concentrations (MICs) and induced mutation rates for each drug-strain combination. We first show that significant changes in MICs are largely confined to DNA-damaging antibiotics, with strains containing a constitutively repressed SOS response impacted to a greater extent than hyperactivated strains. Second, antibiotic-induced mutation rates were suppressed when SOS activity was reduced, and this trend was observed across a wider spectrum of antibiotics. Finally, perturbing either LexA or RecA proved to be equally viable strategies for targeting the SOS response. Our work provides support for multiple adjuvant strategies, while also suggesting that the combination of an SOS inhibitor with a DNA-damaging antibiotic could offer the best potential for lowering MICs and decreasing acquired drug resistance. IMPORTANCE Our antibiotic arsenal is becoming depleted, in part, because bacteria have the ability to rapidly adapt and acquire resistance to our best agents. The SOS pathway, a widely conserved DNA damage stress response in bacteria, is activated by many antibiotics and has been shown to play central role in
Mo, Charlie Y.; Manning, Sara A.; Roggiani, Manuela; Culyba, Matthew J.; Samuels, Amanda N.; Sniegowski, Paul D.; Goulian, Mark
ABSTRACT The bacterial SOS response is a DNA damage repair network that is strongly implicated in both survival and acquired drug resistance under antimicrobial stress. The two SOS regulators, LexA and RecA, have therefore emerged as potential targets for adjuvant therapies aimed at combating resistance, although many open questions remain. For example, it is not well understood whether SOS hyperactivation is a viable therapeutic approach or whether LexA or RecA is a better target. Furthermore, it is important to determine which antimicrobials could serve as the best treatment partners with SOS-targeting adjuvants. Here we derived Escherichia coli strains that have mutations in either lexA or recA genes in order to cover the full spectrum of possible SOS activity levels. We then systematically analyzed a wide range of antimicrobials by comparing the mean inhibitory concentrations (MICs) and induced mutation rates for each drug-strain combination. We first show that significant changes in MICs are largely confined to DNA-damaging antibiotics, with strains containing a constitutively repressed SOS response impacted to a greater extent than hyperactivated strains. Second, antibiotic-induced mutation rates were suppressed when SOS activity was reduced, and this trend was observed across a wider spectrum of antibiotics. Finally, perturbing either LexA or RecA proved to be equally viable strategies for targeting the SOS response. Our work provides support for multiple adjuvant strategies, while also suggesting that the combination of an SOS inhibitor with a DNA-damaging antibiotic could offer the best potential for lowering MICs and decreasing acquired drug resistance. IMPORTANCE Our antibiotic arsenal is becoming depleted, in part, because bacteria have the ability to rapidly adapt and acquire resistance to our best agents. The SOS pathway, a widely conserved DNA damage stress response in bacteria, is activated by many antibiotics and has been shown to play central role
Ribeiro-Varandas, Edna; Pereira, H Sofia; Viegas, Wanda; Delgado, Margarida
Bisphenol A (BPA) is capable of mimicking endogenous hormones with potential consequences for human health and BPA exposure has been associated with several human diseases including neuropsychiatric disorders. Here, quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) results show that BPA at low concentrations (10 ng/mL and 1 μg/mL) induces differential transcript levels of four biomarker genes for Major Depressive Disorder (MDD) in HT29 human colon adenocarcinona cell line and Human Umbilical Vein Endothelial Cells (HUVEC). These results substantiate increasing concerns of BPA exposure in levels currently detected in humans. PMID:27010169
Brown, Eric L.; Xue, Qiong; Jiang, Zhi-Dong; Xu, Yi; DuPont, Herbert L.
Rifaximin is a poorly absorbed semisynthetic antibiotic derivative of rifampin licensed for use in the treatment of traveler's diarrhea. Rifaximin reduces the symptoms of enteric infection, often without pathogen eradication and with limited effects on intestinal flora. Epithelial cells (HEp-2 [laryngeal], HCT-8 [ileocecal], A549 [lung], and HeLa [cervical]) were pretreated with rifaximin (or control antibiotics) prior to the addition of enteroaggregative Escherichia coli (EAEC). EAEC adherence was significantly reduced following rifaximin pretreatment compared to pretreatment with rifampin or doxycycline for three of the four cell lines tested. The rifaximin-mediated changes to epithelial cells were explored further by testing the attachment and internalization of either Bacillus anthracis or Shigella sonnei into A549 or HeLa cells, respectively. The attachment and internalization of B. anthracis were significantly reduced following rifaximin pretreatment. In contrast, neither the attachment nor the internalization of S. sonnei was affected by rifaximin pretreatment of HeLa cells, suggesting that rifaximin-mediated modulation of host cell physiology affected bacteria utilizing distinct attachment/internalization mechanisms differently. In addition, rifaximin pretreatment of HEp-2 cells led to reduced concentrations of inflammatory cytokines from uninfected cells. The study provides evidence that rifaximin-mediated changes in epithelial cell physiology are associated with changes in bacterial attachment/internalization and reduced inflammatory cytokine release. PMID:19858255
Andriamihaja, Mireille; Lan, Annaïg; Beaumont, Martin; Audebert, Marc; Wong, Ximena; Yamada, Kana; Yin, Yulong; Tomé, Daniel; Carrasco-Pozo, Catalina; Gotteland, Martin; Kong, Xiangfeng; Blachier, François
p-Cresol that is produced by the intestinal microbiota from the amino acid tyrosine is found at millimolar concentrations in the human feces. The effects of this metabolite on colonic epithelial cells were tested in this study. Using the human colonic epithelial HT-29 Glc(-/+) cell line, we found that 0.8mM p-cresol inhibits cell proliferation, an effect concomitant with an accumulation of the cells in the S phase and with a slight increase of cell detachment without necrotic effect. At this concentration, p-cresol inhibited oxygen consumption in HT-29 Glc(-/+) cells. In rat normal colonocytes, p-cresol also inhibited respiration. Pretreatment of HT-29 Glc(-/+) cells with 0.8mM p-cresol for 1 day resulted in an increase of the state 3 oxygen consumption and of the cell maximal respiratory capacity with concomitant increased anion superoxide production. At higher concentrations (1.6 and 3.2mM), p-cresol showed similar effects but additionally increased after 1 day the proton leak through the inner mitochondrial membrane, decreasing the mitochondrial bioenergetic activity. At these concentrations, p-cresol was found to be genotoxic toward HT-29 Glc(-/+) and also LS-174T intestinal cells. Lastly, a decreased ATP intracellular content was observed after 3 days treatment. p-Cresol at 0.8mM concentration inhibits colonocyte respiration and proliferation. In response, cells can mobilize their "respiratory reserve." At higher concentrations, p-cresol pretreatment uncouples cell respiration and ATP synthesis, increases DNA damage, and finally decreases the ATP cell content. Thus, we have identified p-cresol as a metabolic troublemaker and as a genotoxic agent toward colonocytes. PMID:25881551
Erb Downward, John R.; Falkowski, Nicole R.; Mason, Katie L.; Ryan Muraglia; Huffnagle, Gary B.
The introduction of Candida albicans into cefoperazone-treated mice results in changes in bacterial community reassembly. Our objective was to use high-throughput sequencing to characterize at much greater depth the specific changes in the bacterial microbiome. The colonization of C. albicans significantly altered bacterial community reassembly that was evident at multiple taxonomic levels of resolution. There were marked changes in the levels of Bacteriodetes and Lactobacillaceae. Lachnospir...
Bhattarai, Yogesh; Fried, David; Gulbransen, Brian; Kadrofske, Mark; Fernandes, Roxanne; Xu, Hui; Galligan, James
We tested the hypothesis that colonic enteric neurotransmission and smooth muscle cell (SMC) function are altered in mice fed a high-fat diet (HFD). We used wild-type (WT) mice and mice lacking the β1-subunit of the BK channel (BKβ1 (-/-)). WT mice fed a HFD had increased myenteric plexus oxidative stress, a 28% decrease in nitrergic neurons, and a 20% decrease in basal nitric oxide (NO) levels. Circular muscle inhibitory junction potentials (IJPs) were reduced in HFD WT mice. The NO synthase inhibitor nitro-l-arginine (NLA) was less effective at inhibiting relaxations in HFD compared with control diet (CD) WT mice (11 vs. 37%, P < 0.05). SMCs from HFD WT mice had depolarized membrane potentials (-47 ± 2 mV) and continuous action potential firing compared with CD WT mice (-53 ± 2 mV, P < 0.05), which showed rhythmic firing. SMCs from HFD or CD fed BKβ1 (-/-) mice fired action potentials continuously. NLA depolarized membrane potential and caused continuous firing only in SMCs from CD WT mice. Sodium nitroprusside (NO donor) hyperpolarized membrane potential and changed continuous to rhythmic action potential firing in SMCs from HFD WT and BKβ1 (-/-) mice. Migrating motor complexes were disrupted in colons from BKβ1 (-/-) mice and HFD WT mice. BK channel α-subunit protein and β1-subunit mRNA expression were similar in CD and HFD WT mice. We conclude that HFD-induced obesity disrupts inhibitory neuromuscular transmission, SMC excitability, and colonic motility by promoting oxidative stress, loss of nitrergic neurons, and SMC BK channel dysfunction. PMID:27288421
Thu Thuy Nguyen
Full Text Available Fecal excretion of antibiotics and resistant bacteria in the environment are major public health threats associated with extensive farming and modern medical care. Innovative strategies that can reduce the intestinal antibiotic concentrations during treatments are in development. However, the effect of lower exposure on the amount of resistant enterobacteria excreted has not been quantified, making it difficult to anticipate the impact of these strategies. Here, we introduce a bacterial kinetic model to capture the complex relationships between drug exposure, loss of susceptible enterobacteria and growth of resistant strains in the feces of piglets receiving placebo, 1.5 or 15 mg/kg/day ciprofloxacin, a fluoroquinolone, for 5 days. The model could well describe the kinetics of drug susceptible and resistant enterobacteria observed during treatment, and up to 22 days after treatment cessation. Next, the model was used to predict the expected amount of resistant enterobacteria excreted over an average piglet's lifetime (150 days when varying drug exposure and treatment duration. For the clinically relevant dose of 15 mg/kg/day for 5 days, the total amount of resistant enterobacteria excreted was predicted to be reduced by 75% and 98% when reducing treatment duration to 3 and 1 day treatment, respectively. Alternatively, for a fixed 5-days treatment, the level of resistance excreted could be reduced by 18%, 33%, 57.5% and 97% if 3, 5, 10 and 30 times lower levels of colonic drug concentrations were achieved, respectively. This characterization on in vivo data of the dynamics of resistance to antibiotics in the colonic flora could provide new insights into the mechanism of dissemination of resistance and can be used to design strategies aiming to reduce it.
Jones, Robert T
Abstract Background Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. Results A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28°C) and human (37°C) temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS)-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR) binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. Conclusions We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect through mediation of
Joyce Susan A
Full Text Available Abstract Background Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. Results A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28°C and human (37°C temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. Conclusions We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect
Full Text Available Some plants can tolerate and even detoxify soils contaminated with heavy metals. This detoxification ability may depend on what chemical forms of metals are taken up by plants and how the plants distribute the toxins in their tissues. This, in turn, may have an important impact on phytoremediation. We investigated the impact of arbuscular mycorrhizal (AM fungus, Glomus intraradices, on the subcellular distribution and chemical forms of cadmium (Cd in alfalfa (Medicago sativa L. that were grown in Cd-added soils. The fungus significantly colonized alfalfa roots by day 25 after planting. Colonization of alfalfa by G. intraradices in soils contaminated with Cd ranged from 17% to 69% after 25-60 days and then decreased to 43%. The biomass of plant shoots with AM fungi showed significant 1.7-fold increases compared to no AM fungi addition under the treatment of 20 mg kg(-1 Cd. Concentrations of Cd in the shoots of alfalfa under 0.5, 5, and 20 mgkg(-1 Cd without AM fungal inoculation are 1.87, 2.92, and 2.38 times higher, respectively, than those of fungi-inoculated plants. Fungal inoculation increased Cd (37.2-80.5% in the cell walls of roots and shoots and decreased in membranes after 80 days of incubation compared to untreated plants. The proportion of the inactive forms of Cd in roots was higher in fungi-treated plants than in controls. Furthermore, although fungi-treated plants had less overall Cd in subcellular fragments in shoots, they had more inactive Cd in shoots than did control plants. These results provide a basis for further research on plant-microbe symbioses in soils contaminated with heavy metals, which may potentially help us develop management regimes for phytoremediation.
Nomura, Ryota; Ogaya, Yuko; Nakano, Kazuhiko
Streptococcus mutans is a major pathogen of dental caries. Collagen-binding proteins (CBPs) (approximately 120 kDa), termed Cnm and Cbm, are regarded as important cell surface antigens related to the adherence of S. mutans to collagenous tissue. Furthermore, CBP-positive S. mutans strains are associated with various systemic diseases involving bacteremia, such as infective endocarditis. Endodontic infection is considered to be an important cause of bacteremia, but little is known regarding the presence of S. mutans in dental pulp tissue. In the present study, the distribution and virulence of S. mutans in dental pulp tissues were investigated by focusing on CBPs. Adhesion and invasion properties of various S. mutans strains were analyzed using human dental pulp fibroblasts (HDPFs). CBP-positive strains had a significantly higher rate of adhesion to HDPFs compared with CBP-defective isogenic mutant strains (Pcanal specimens was then analyzed by PCR. We found that approximately 50% of the root canal specimens were positive for S. mutans. Approximately 20% of these strains were Cnm-positive, while no Cbm-positive strains were isolated. The Cnm-positive strains isolated from the specimens showed adhesion to HDPFs. Our results suggest that CBP-positive S. mutans strains exhibit high colonization in dental pulp. This could be a possible virulence factor for various systemic diseases. PMID:27442266
Chelius Marisa K.
Full Text Available Wind Cave (WICA in the Black Hills of South Dakota, like many mostly dry caves in temperate regions is an energy-starved system.The biotic communities that reside in these systems are low in diversity and simple in structure, and sensitive to changes in externalinputs of organic matter. Caves open to tourist traffic offer an opportunity to study the impacts of organic matter amendments in theform of human and rodent hair and dander, clothing lint, material from rodent activity (nesting materials and feces, and algal growthin and around artificial lighting. This study reports on the impacts of carbon amendments from humans and rodents on the bacterialand archaeal communities within the sediments of WICA from annual surveys and from a manipulative study that added lint (‘L’;cellulose plus rodent dander and rodent hair, rodent feces (‘F’, and a combination of both (‘LF’. The survey confirmed that bacterialbiomass was higher in regions of the cave with the highest rates of lint (hair and natural clothing fibers input. The manipulative studyfound that organic amendments in the forms of lint (L and rodent feces (F altered the WICA bacterial community structure in bothabundance and diversity, with the combined lint and feces (LF amendment having the most significant response. The high similarityof the LF and L communities suggests that the cave bacterial community is more carbon than nitrogen limited. The implication ofcave development to management practices is immediate and practical. Even small amounts of lint and organic matter foreign tocave bacteria significantly compromise the integrity of the endemic community resulting in the replacement of undescribed speciesby assemblages with at best, unknown impacts to natural cave features.
Natalia Pimentel Moreno
Full Text Available Purpose: To study the aerobic bacterial microbiota of the conjunctiva in diabetic patients with regard to the management of diabetes, assessed using glycated hemoglobin levels. Methods: A cross-sectional study was conducted using conjunctival smears of diabetic patients from both sexes and with different ages, residing in two different Brazilian cities (Sorocaba and Rio Branco. A control group of non-diabetic patients was also included. The diabetic patients were considered to have controlled diabetes when their glycated hemoglobin level was ≤7% and blood glucose level was ≤126 mg/dL. Patients with non-controlled diabetes were those with glycated hemoglobin levels >7% and blood glucose levels >126 mg/dL. The samples obtained were inoculated in Brain-Heart Infusion broth and in culture media for aerobic bacteria (blood and chocolate agars; bacterial growth was evaluated in a microbiology laboratory. Results: A total of 120 eyes of 120 patients were included in the present study. The percentage of cultures in which bacterial growth was observed was greater in diabetic patients, although the difference was not statistically significant (p=0.103. There was a greater trend toward bacterial growth in the conjunctiva of diabetic patients with altered fasting blood glucose. There was no difference in the frequency of bacterial growth on the conjunctiva between diabetic patients with normal or altered glycated hemoglobin levels. In Sorocaba, conjunctival bacterial growth was similar to that observed in Rio Branco. The microorganism most frequently detected in the present study was Staphylococcus epidermidis, followed by Staphylococcus aureus, Proteus mirabilis, and Escherichia coli. Conclusion: There was no difference between diabetic patients with normal or altered glycated hemoglobin levels. The microorganisms found were similar to those found in studies investigating the conjunctival bacterial flora of diabetic and non-diabetic patients.
Kaler, Pawan; Augenlicht, Leonard; Klampfer, Lidija
Background Tumor cells become addicted to both activated oncogenes and to proliferative and pro-survival signals provided by the abnormal tumor microenvironment. Although numerous soluble factors have been identified that shape the crosstalk between tumor cells and stroma, it has not been established how oncogenic mutations in the tumor cells alter their interaction with normal cells in the tumor microenvironment. Principal Findings We showed that the isogenic HCT116 and Hke-3 cells, which di...
Nimusiima, Jean; Köberl, Martina; Tumuhairwe, John Baptist; Kubiriba, Jerome; Staver, Charles; Berg, Gabriele
Africa is among the continents where the battle over genetically modified crops is currently being played out. The impact of GM in Africa could potentially be very positive. In Uganda, researchers have developed transgenic banana lines resistant to banana Xanthomonas wilt. The transgenic lines expressing hrap and pflp can provide a timely solution to the pandemic. However, the impact of the transgenes expression on non-target microorganisms has not yet been investigated. To study this effect, transgenic and control lines were grown under field conditions and their associated microbiome was investigated by 16S rRNA gene profiling combining amplicon sequencing and molecular fingerprinting. Three years after sucker planting, no statistically significant differences between transgenic lines and their non-modified predecessors were detected for their associated bacterial communities. The overall gammaproteobacterial rhizosphere microbiome was highly dominated by Xanthomonadales, while Pseudomonadales and Enterobacteriales were accumulated in the pseudostem. Shannon indices revealed much higher diversity in the rhizosphere than in the pseudostem endosphere. However, the expression of the transgenes did not result in changes in the diversity of Gammaproteobacteria, the closest relatives of the target pathogen. In this field experiment, the expression of the resistance genes appears to have no consequences for non-target rhizobacteria and endophytes. PMID:26657016
Franzenburg, Sören; Fraune, Sebastian; Künzel, Sven; Baines, John F.; Domazet-Lošo, Tomislav; Bosch, Thomas C. G.
Toll-like receptor (TLR) signaling is one of the most important signaling cascades of the innate immune system of vertebrates. Studies in invertebrates have focused on the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans, and there is little information regarding the evolutionary origin and ancestral function of TLR signaling. In Drosophila, members of the Toll-like receptor family are involved in both embryonic development and innate immunity. In C. elegans, a clear immune function of the TLR homolog TOL-1 is controversial and central components of vertebrate TLR signaling including the key adapter protein myeloid differentiation primary response gene 88 (MyD88) and the transcription factor NF-κB are not present. In basal metazoans such as the cnidarians Hydra magnipapillata and Nematostella vectensis, all components of the vertebrate TLR signaling cascade are present, but their role in immunity is unknown. Here, we use a MyD88 loss-of-function approach in Hydra to demonstrate that recognition of bacteria is an ancestral function of TLR signaling and that this process contributes to both host-mediated recolonization by commensal bacteria as well as to defense against bacterial pathogens. PMID:23112184
Maity, Chiranjit; Lahiri, Pallavi; Adak, Atanu; Ghosh, Kuntal; Pati, Bikas R; Mondal, Keshab C
Present study deals with the straight impact of hypobaric hypoxia on the quantity and composition of some predominant fecal microflora and its functional aspects. For that, isolated fecal contents of rat were exposed to two different simulated air pressures (70 kPa and 40 kPa) for different time durations (1, 3, and 5 h) and the bacterial community composition was compared with normobaric groups (101.3 kPa). It was found that the total anaerobes, Escherichia coli, Enterbacters spp., Bifidobacterium spp., Clostridium spp. were increased whereas total aerobes were decreased at both hypobaric treatments. The increased number of amplicon was detected in the pressure-treated groups than the control that clearly mentioned the disruption of microbiota structure at different simulated hypobaric-hypoxia. The amylase, protease, tannase, β-glucuronidase, and alkaline phosphatase activities were increased at these atmospheric pressures. Thus, the present investigation demonstrates that the hypobaric hypoxia is an important environmental factor which can strongly modulate the composition of intestinal flora as well as microflora-derived functional aspects. PMID:24215884
Bas ter Braak
Full Text Available Pea aphids have an obligate nutritional symbiosis with the bacteria Buchneraaphidicola and frequently also harbor one or more facultative symbionts. Aphids are also susceptible to bacterial pathogen infections, and it has been suggested that aphids have a limited immune response towards such pathogen infections compared to other, more well-studied insects. However, aphids do possess at least some of the genes known to be involved in bacterial immune responses in other insects, and immune-competent hemocytes. One possibility is that immune priming with microbial elicitors could stimulate immune protection against subsequent bacterial infections, as has been observed in several other insect systems. To address this hypothesis we challenged aphids with bacterial immune elicitors twenty-four hours prior to live bacterial pathogen infections and then compared their survival rates to aphids that were not pre-exposed to bacterial signals. Using two aphid genotypes, we found no evidence for immune protection conferred by immune priming during infections with either Serratia marcescens or with Escherichia coli. Immune priming was not altered by the presence of facultative, beneficial symbionts in the aphids. In the absence of inducible immune protection, aphids may allocate energy towards other defense traits, including production of offspring with wings that could escape deteriorating conditions. To test this, we monitored the ratio of winged to unwinged offspring produced by adult mothers of a single clone that had been exposed to bacterial immune elicitors, to live E. coli infections or to no challenge. We found no correlation between immune challenge and winged offspring production, suggesting that this mechanism of defense, which functions upon exposure to fungal pathogens, is not central to aphid responses to bacterial infections.
Kohler, Tyler J; Van Horn, David J; Darling, Joshua P; Takacs-Vesbach, Cristina D; McKnight, Diane M
Microbial mats are abundant in many alpine and polar aquatic ecosystems. With warmer temperatures, new hydrologic pathways are developing in these regions and increasing dissolved nutrient fluxes. In the McMurdo Dry Valleys, thermokarsting may release both nutrients and sediment, and has the potential to influence mats in glacial meltwater streams. To test the role of nutrient inputs on community structure, we created nutrient diffusing substrata (NDS) with agar enriched in N, P and N + P, with controls, and deployed them into two Dry Valley streams. We found N amendments (N and N + P) to have greater chlorophyll-a concentrations, total algal biovolume, more fine filamentous cyanobacteria and a higher proportion of live diatoms than other treatments. Furthermore, N treatments were substantially elevated in Bacteroidetes and the small diatom, Fistulifera pelliculosa. On the other hand, species richness was almost double in P and N + P treatments over others, and coccoid green algae and Proteobacteria were more abundant in both streams. Collectively, these data suggest that nutrients have the potential to stimulate growth and alter community structure in glacial meltwater stream microbial mats, and the recent erosion of permafrost and accelerated glacial melt will likely impact resident biota in polar lotic systems here and elsewhere. PMID:26940086
Shen, Ju-Pei; Chen, C. R.; Lewis, Tom
Effects of fire on biogeochemical cycling in terrestrial ecosystem are widely acknowledged, while few studies have focused on the bacterial community under the disturbance of long-term frequent prescribed fire. In this study, three treatments (burning every two years (B2), burning every four years (B4) and no burning (B0)) were applied for 38 years in an Australian wet sclerophyll forest. Results showed that bacterial alpha diversity (i.e. bacterial OTU) in the top soil (0-10 cm) was significantly higher in the B2 treatment compared with the B0 and B4 treatments. Non-metric multidimensional analysis (NMDS) of bacterial community showed clear separation of the soil bacterial community structure among different fire frequency regimes and between the depths. Different frequency fire did not have a substantial effect on bacterial composition at phylum level or bacterial 16S rRNA gene abundance. Soil pH and C:N ratio were the major drivers for bacterial community structure in the most frequent fire treatment (B2), while other factors (EC, DOC, DON, MBC, NH4+, TC and TN) were significant in the less frequent burning and no burning treatments (B4 and B0). This study suggested that burning had a dramatic impact on bacterial diversity but not abundance with more frequent fire.
Shen, Ju-pei; Chen, C R; Lewis, Tom
Effects of fire on biogeochemical cycling in terrestrial ecosystem are widely acknowledged, while few studies have focused on the bacterial community under the disturbance of long-term frequent prescribed fire. In this study, three treatments (burning every two years (B2), burning every four years (B4) and no burning (B0)) were applied for 38 years in an Australian wet sclerophyll forest. Results showed that bacterial alpha diversity (i.e. bacterial OTU) in the top soil (0-10 cm) was significantly higher in the B2 treatment compared with the B0 and B4 treatments. Non-metric multidimensional analysis (NMDS) of bacterial community showed clear separation of the soil bacterial community structure among different fire frequency regimes and between the depths. Different frequency fire did not have a substantial effect on bacterial composition at phylum level or bacterial 16S rRNA gene abundance. Soil pH and C:N ratio were the major drivers for bacterial community structure in the most frequent fire treatment (B2), while other factors (EC, DOC, DON, MBC, NH4(+), TC and TN) were significant in the less frequent burning and no burning treatments (B4 and B0). This study suggested that burning had a dramatic impact on bacterial diversity but not abundance with more frequent fire. PMID:26787458
Gelhaye, E.; Gehin, A; Petitdemange, H.
Cellulose colonization by Clostridium cellulolyticum was studied by using [methyl-3H]thymidine incorporation. The colonization process indicated that a part of the bacterial population was released from cellulose to the liquid phase before binding and colonizing another adhesion site of the cellulose. We postulate that cellulose colonization occurs according to the following process: adhesion, colonization, release, and readhesion.
Robin L P Jump
Full Text Available BACKGROUND: The intestinal microbiota protect the host against enteric pathogens through a defense mechanism termed colonization resistance. Antibiotics excreted into the intestinal tract may disrupt colonization resistance and alter normal metabolic functions of the microbiota. We used a mouse model to test the hypothesis that alterations in levels of bacterial metabolites in fecal specimens could provide useful biomarkers indicating disrupted or intact colonization resistance after antibiotic treatment. METHODS: To assess in vivo colonization resistance, mice were challenged with oral vancomycin-resistant Enterococcus or Clostridium difficile spores at varying time points after treatment with the lincosamide antibiotic clindamycin. For concurrent groups of antibiotic-treated mice, stool samples were analyzed using quantitative real-time polymerase chain reaction to assess changes in the microbiota and using non-targeted metabolic profiling. To assess whether the findings were applicable to another antibiotic class that suppresses intestinal anaerobes, similar experiments were conducted with piperacillin/tazobactam. RESULTS: Colonization resistance began to recover within 5 days and was intact by 12 days after clindamycin treatment, coinciding with the recovery bacteria from the families Lachnospiraceae and Ruminococcaceae, both part of the phylum Firmicutes. Clindamycin treatment caused marked changes in metabolites present in fecal specimens. Of 484 compounds analyzed, 146 (30% exhibited a significant increase or decrease in concentration during clindamycin treatment followed by recovery to baseline that coincided with restoration of in vivo colonization resistance. Identified as potential biomarkers of colonization resistance, these compounds included intermediates in carbohydrate or protein metabolism that increased (pentitols, gamma-glutamyl amino acids and inositol metabolites or decreased (pentoses, dipeptides with clindamycin treatment
Colorectal cancer; Cancer - colon; Rectal cancer; Cancer - rectum; Adenocarcinoma - colon; Colon - adenocarcinoma ... In the United States, colorectal cancer is one of the leading causes of deaths due to cancer. Early diagnosis can often lead to a complete cure. Almost ...
Shen, Ju-Pei; Chen, C. R.; Lewis, Tom
Effects of fire on biogeochemical cycling in terrestrial ecosystem are widely acknowledged, while few studies have focused on the bacterial community under the disturbance of long-term frequent prescribed fire. In this study, three treatments (burning every two years (B2), burning every four years (B4) and no burning (B0)) were applied for 38 years in an Australian wet sclerophyll forest. Results showed that bacterial alpha diversity (i.e. bacterial OTU) in the top soil (0–10 cm) was signific...
Thomas Raymond H
Full Text Available Abstract Gastrointestinal symptoms and altered blood phospholipid profiles have been reported in patients with autism spectrum disorders (ASD. Most of the phospholipid analyses have been conducted on the fatty acid composition of isolated phospholipid classes following hydrolysis. A paucity of information exists on how the intact phospholipid molecular species are altered in ASD. We applied ESI/MS to determine how brain and blood intact phospholipid species were altered during the induction of ASD-like behaviors in rats following intraventricular infusions with the enteric bacterial metabolite propionic acid. Animals were infused daily for 8 days, locomotor activity assessed, and animals killed during the induced behaviors. Propionic acid infusions increased locomotor activity. Lipid analysis revealed treatment altered 21 brain and 30 blood phospholipid molecular species. Notable alterations were observed in the composition of brain SM, diacyl mono and polyunsaturated PC, PI, PS, PE, and plasmalogen PC and PE molecular species. These alterations suggest that the propionic acid rat model is a useful tool to study aberrations in lipid metabolism known to affect membrane fluidity, peroxisomal function, gap junction coupling capacity, signaling, and neuroinflammation, all of which may be associated with the pathogenesis of ASD.
Lifelong consumption of soy protein isolate (SPI) reduces the incidence of azoxymethane (AOM)-induced colon tumors in adult male Sprague-Dawley rats. We determined if a maternal SPI diet during pregnancy could protect against colon cancer in progeny. Four groups of male rats were used: a lifetime ...
Maternal antibiotic-induced early changes in microbial colonization selectively modulate colonic permeability and inducible heat shock proteins, and digesta concentrations of alkaline phosphatase and TLR-stimulants in swine offspring.
Full Text Available Elevated intake of high energy diets is a risk factor for the development of metabolic diseases and obesity. High fat diets cause alterations in colonic microbiota composition and increase gut permeability to bacterial lipopolysaccharide, and subsequent low-grade chronic inflammation in mice. Chronic inflammatory bowel diseases are increasing worldwide and may involve alterations in microbiota-host dialog. Metabolic disorders appearing in later life are also suspected to reflect changes in early programming. However, how the latter affects the colon remains poorly studied. Here, we hypothesized that various components of colonic physiology, including permeability, ion exchange and protective inducible heat shock proteins (HSP are influenced in the short- and long-terms by early disturbances in microbial colonization. The hypothesis was tested in a swine model. Offspring were born to control mothers (n = 12 or mothers treated with the antibiotic (ATB amoxicillin around parturition (n = 11. Offspring were slaughtered between 14 and 42 days of age to study short-term effects. For long-term effects, young adult offspring from the same litters consumed a normal or a palm oil-enriched diet for 4 weeks between 140 and 169 days of age. ATB treatment transiently modified maternal fecal microbiota although the minor differences observed for offspring colonic microbiota were nonsignificant. In the short-term, consistently higher HSP27 and HSP70 levels and transiently increased horseradish peroxidase permeability in ATB offspring colon were observed. Importantly, long-term consequences included reduced colonic horseradish peroxidase permeability, and increased colonic digesta alkaline phosphatase (AP and TLR2- and TLR4-stimulant concentrations in rectal digesta in adult ATB offspring. Inducible HSP27 and HSP70 did not change. Interactions between early ATB treatment and later diet were noted for paracellular permeability and concentrations of colonic
Full Text Available Oceanic basalts host diverse microbial communities with various metabolisms involved in C, N, S and Fe biogeochemical cycles which may contribute to mineral and glass alteration processes at, and below the seafloor. In order to study the microbial colonization on basaltic glasses and their potential biotic/abiotic weathering products, two colonization modules called AISICS (Autonomous In Situ Instrumented Colonization System were deployed in hydrothermal deep-sea sediments at the Guaymas Basin for 8 days and 22 days. Each AISICS module contained 18 colonizers (including sterile controls filled with basaltic glasses of contrasting composition. Chemical analyses of ambient fluids sampled through the colonizers showed a greater contribution of hydrothermal fluids (maximum temperature 57.6°C for the module deployed during the longer time period. For each colonizer, the phylogenetic diversity and metabolic function of bacterial and archaeal communities were explored using a molecular approach by cloning and sequencing. Results showed large microbial diversity in all colonizers. The bacterial distribution is primarily linked to the deployment duration, as well as the depth for the short deployment time module. Some 16s rRNA sequences form a new cluster of Epsilonproteobacteria. Within the Archaea the retrieved diversity could not be linked to either duration, depth or substrata. However, mcrA gene sequences belonging to the ANME-1 mcrA-guaymas cluster were found sometimes associated with their putative sulfate-reducers syntrophs depending on the colonizers. Although no specific glass alteration texture was identified, nano-crystals of barite and pyrite were observed in close association with organic matter, suggesting a possible biological mediation. This study gives new insights into the colonization steps of volcanic rock substrates and the capability of microbial communities to exploit new environmental conditions.
Gelsomino, Giada; Corsetto, Paola A.; Campia, Ivana; Montorfano, Gigliola; Kopecka, Joanna; Castella, Barbara; Gazzano, Elena; Ghigo, Dario; Rizzo, Angela M; Riganti, Chiara
Background The activity of P-glycoprotein (Pgp) and multidrug resistance related protein 1 (MRP1), two membrane transporters involved in multidrug resistance of colon cancer, is increased by high amounts of cholesterol in plasma membrane and detergent resistant membranes (DRMs). It has never been investigated whether omega 3 polyunsatured fatty acids (PUFAs), which modulate cholesterol homeostasis in dyslipidemic syndromes and have chemopreventive effects in colon cancer, may affect the respo...
Full Text Available Purinergic P2X receptors contribute to neurotransmission in the gut. P2X receptors are ligand-gated cation channels that mediate synaptic excitation in subsets of enteric neurons. The present study evaluated colonic motility in vitro and in vivo in wild type (WT and P2X2 and P2X3 subunit knockout (KO mice. The muscarinic receptor agonist, bethanechol (0.3-3 micromolar, caused similar contractions of the longitudinal muscle in colon segments from WT, P2X2 and P2X3 subunit KO mice. Nicotine (1-300 micromolar, acting at neuronal nicotinic receptors, caused similar longitudinal muscle relaxations in colonic segments from WT and P2X2 and P2X3 subunit KO mice. Nicotine-induced relaxations were inhibited by nitro-L-arginine (NLA, 100 micromolar and apamin (0.1 micromolar which block inhibitory neuromuscular transmission. ATP (1-1000 micromolar caused contractions only in the presence of NLA and apamin. ATP-induced contractions were similar in colon segments from WT, P2X2 and P2X3 KO mice. The mouse colon generates spontaneous migrating motor complexes (MMCs in vitro. The MMC frequency was higher in P2X2 KO compared to WT tissues; other parameters of the MMC were similar in colon segments from WT, P2X2 and P2X3 KO mice. 5-Hydroxytryptophan-induced fecal output was similar in WT, P2X2 and P2X3 KO mice. These data indicate that nicotinic receptors are located predominately on inhibitory motor neurons supplying the longitudinal muscle in the mouse colon. P2X2 or P2X3 subunit containing receptors are not localized to motorneurons supplying the longitudinal muscle. Synaptic transmission mediated by P2X2 or P2X3 subunit containing receptors is not required for propulsive motility in the mouse colon.
Full Text Available Bacteria lose or gain genetic material and through selection, new variants become fixed in the population. Here we provide the first, genome-wide example of a single bacterial strain's evolution in different deliberately colonized patients and the surprising insight that hosts appear to personalize their microflora. By first obtaining the complete genome sequence of the prototype asymptomatic bacteriuria strain E. coli 83972 and then resequencing its descendants after therapeutic bladder colonization of different patients, we identified 34 mutations, which affected metabolic and virulence-related genes. Further transcriptome and proteome analysis proved that these genome changes altered bacterial gene expression resulting in unique adaptation patterns in each patient. Our results provide evidence that, in addition to stochastic events, adaptive bacterial evolution is driven by individual host environments. Ongoing loss of gene function supports the hypothesis that evolution towards commensalism rather than virulence is favored during asymptomatic bladder colonization.
Rademacher, Antje [Leibniz-Institut fuer Agrartechnik Potsdam-Bornim e.V. (ATB), Potsdam (Germany). Abt. Bioverfahrenstechnik; Technische Univ. Berlin (Germany). Inst. fuer Technischen Umweltschutz; Nolte, Christine; Schoenberg, Mandy; Klocke, Michael [Leibniz-Institut fuer Agrartechnik Potsdam-Bornim e.V. (ATB), Potsdam (Germany). Abt. Bioverfahrenstechnik
Agricultural biogas plants were operated in most cases below their optimal performance. An increase in the fermentation temperature and a spatial separation of hydrolysis/acetogenesis and methanogenesis are known strategies in improving and stabilizing biogas production. In this study, the dynamic variability of the bacterial and archaeal community was monitored within a two-phase leach bed biogas reactor supplied with rye silage and straw during a stepwise temperature increase from 55 to 75 C within the leach bed reactor (LBR), using TRFLP analyses. To identify the terminal restriction fragments that were obtained, bacterial and archaeal 16S rRNA gene libraries were constructed. Above 65 C, the bacterial community structure changed from being Clostridiales-dominated toward being dominated by members of the Bacteroidales, Clostridiales, and Thermotogales orders. Simultaneously, several changes occurred, including a decrease in the total cell count, degradation rate, and biogas yield along with alterations in the intermediate production. A bioaugmentation with compost at 70 C led to slight improvements in the reactor performance; these did not persist at 75 C. However, the archaeal community within the downstream anaerobic filter reactor (AF), operated constantly at 55 C, altered by the temperature increase in the LBR. At an LBR temperature of 55 C, members of the Methanobacteriales order were prevalent in the AF, whereas at higher LBR temperatures Methanosarcinales prevailed. Altogether, the best performance of this two-phase reactor was achieved at an LBR temperature of below 65 C, which indicates that this temperature range has a favorable effect on the microbial community responsible for the production of biogas. (orig.)
Full Text Available Introduction. Since the NF-κB pathway regulates both inflammation and host defense, it is uncertain whether interventions targeting NF-κB would be beneficial in sepsis. Based on the kinetics of the innate immune response, we postulated that selective NF-κB inhibition during a defined time period after the onset of sepsis would reduce acute lung injury without compromising bacterial host defense. Methods. Mice underwent cecal ligation and puncture (CLP. An NF-κB inhibitor, BMS-345541 (50 µg/g mice, was administered by peroral gavage beginning 2 hours after CLP and repeated at 6 hour intervals for 2 additional doses. Results. Mice treated with BMS-345541 after CLP showed reduced neutrophilic alveolitis and lower levels of KC in bronchoalveolar lavage fluid compared to mice treated with CLP+vehicle. In addition, mice treated with CLP+BMS had minimal histological evidence of lung injury and normal wet-dry ratios, indicating protection from acute lung injury. Treatment with the NF-κB inhibitor did not affect the ability of cultured macrophages to phagocytose bacteria and did not alter bacterial colony counts in blood, lung tissue, or peritoneal fluid at 24 hours after CLP. While BMS-345541 treatment did not alter mortality after CLP, our results showed a trend towards improved survival. Conclusion. Transiently blocking NF-κB activity after the onset of CLP-induced sepsis can effectively reduce acute lung injury in mice without compromising bacterial host defense or survival after CLP.
Romano-Keeler, Joann; Weitkamp, Jörn-Hendrik
While critical for normal development, the exact timing of establishment of the intestinal microbiome is unknown. For example, although preterm labor and birth have been associated with bacterial colonization of the amniotic cavity and fetal membranes for many years, the prevailing dogma of a sterile intrauterine environment during normal term pregnancies has been challenged more recently. While found to be a key contributor of evolution in the animal kingdom, maternal transmission of commensal bacteria may also constitute a critical process during healthy pregnancies in humans with yet unclear developmental importance. Metagenomic sequencing has elucidated a rich placental microbiome in normal term pregnancies likely providing important metabolic and immune contributions to the growing fetus. Conversely, an altered microbial composition during pregnancy may produce aberrant metabolites impairing fetal brain development and life-long neurological outcomes. Here we review the current understanding of microbial colonization at the feto-maternal interface and explain how normal gut colonization drives a balanced neonatal mucosal immune system, while dysbiosis contributes to aberrant immune function early in life and beyond. We discuss how maternal genetics, diet, medications, and probiotics inform the fetal microbiome in preparation for perinatal and postnatal bacterial colonization. PMID:25310759
Dillon, SM; Lee, EJ; Kotter, CV; Austin, GL; Gianella, S; Siewe, B; Smith, DM; Landay, AL; McManus, MC; Robertson, CE; Frank, DN; McCarter, MD; Wilson, CC
HIV-1-associated disruption of intestinal homeostasis is a major factor contributing to chronic immune activation and inflammation. Dendritic cells (DCs) are crucial in maintaining intestinal homeostasis, but the impact of HIV-1 infection on intestinal DC number and function has not been extensively studied. We compared the frequency and activation/maturation status of colonic myeloid DC (mDC) subsets (CD1c+ and CD1cneg) and plasmacytoid DCs in untreated HIV-1-infected subjects with uninfected controls. Colonic mDCs in HIV-1-infected subjects had increased CD40 but decreased CD83 expression, and CD40 expression on CD1c+ mDCs positively correlated with mucosal HIV-1 viral load, with mucosal and systemic cytokine production, and with frequencies of activated colon and blood T cells. Percent of CD83+CD1c+ mDCs negatively correlated with frequencies of IFN-γ-producing colon CD4+ and CD8+ T cells. CD40 expression on CD1c+ mDCs positively associated with abundance of high prevalence mucosal Prevotella copri and P. stercorea, but negatively associated with a number of low prevalence mucosal species including Rumminococcus bromii. CD1c+ mDC cytokine production was greater in response to in vitro stimulation with Prevotella species relative to R. bromii. These findings suggest that during HIV infection, colonic mDCs become activated upon exposure to mucosal pathobiont bacteria leading to mucosal and systemic immune activation. PMID:25921339
Dillon, S M; Lee, E J; Kotter, C V; Austin, G L; Gianella, S; Siewe, B; Smith, D M; Landay, A L; McManus, M C; Robertson, C E; Frank, D N; McCarter, M D; Wilson, C C
HIV-1-associated disruption of intestinal homeostasis is a major factor contributing to chronic immune activation and inflammation. Dendritic cells (DCs) are crucial in maintaining intestinal homeostasis, but the impact of HIV-1 infection on intestinal DC number and function has not been extensively studied. We compared the frequency and activation/maturation status of colonic myeloid DC (mDC) subsets (CD1c(+) and CD1c(neg)) and plasmacytoid DCs in untreated HIV-1-infected subjects with uninfected controls. Colonic mDCs in HIV-1-infected subjects had increased CD40 but decreased CD83 expression, and CD40 expression on CD1c(+) mDCs positively correlated with mucosal HIV-1 viral load, with mucosal and systemic cytokine production, and with frequencies of activated colon and blood T cells. Percentage of CD83(+)CD1c(+) mDCs negatively correlated with frequencies of interferon-γ-producing colon CD4(+) and CD8(+) T cells. CD40 expression on CD1c(+) mDCs positively associated with abundance of high prevalence mucosal Prevotella copri and Prevotella stercorea but negatively associated with a number of low prevalence mucosal species, including Rumminococcus bromii. CD1c(+) mDC cytokine production was greater in response to in vitro stimulation with Prevotella species relative to R. bromii. These findings suggest that, during HIV infection, colonic mDCs become activated upon exposure to mucosal pathobiont bacteria leading to mucosal and systemic immune activation. PMID:25921339
Zulian, Alessandra; Cancello, Raffaella; Ruocco, Chiara; Gentilini, Davide; Di Blasio, Anna Maria; Danelli, Piergiorgio; Micheletto, Giancarlo; Cesana, Elisabetta; Invitti, Cecilia
Crohn’s disease (CD) is notably characterized by the expansion of visceral fat with small adipocytes expressing a high proportion of anti-inflammatory genes. Conversely, visceral fat depots in ulcerative colitis (UC) patients have never been characterized. Our study aims were a) to compare adipocyte morphology and gene expression profile and bacterial translocation in omental (OM) and mesenteric (MES) adipose tissue of patients with UC and CD, and b) to investigate the effect of bacterial inf...
Alessandra Zulian; Raffaella Cancello; Chiara Ruocco; Davide Gentilini; Anna Maria Di Blasio; Piergiorgio Danelli; Giancarlo Micheletto; Elisabetta Cesana; Cecilia Invitti
Crohn's disease (CD) is notably characterized by the expansion of visceral fat with small adipocytes expressing a high proportion of anti-inflammatory genes. Conversely, visceral fat depots in ulcerative colitis (UC) patients have never been characterized. Our study aims were a) to compare adipocyte morphology and gene expression profile and bacterial translocation in omental (OM) and mesenteric (MES) adipose tissue of patients with UC and CD, and b) to investigate the effect of bacterial inf...
Yang, Hui; Hu, Jinxiang; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed
The interaction between roots and bacterial communities in halophytic species is poorly understood. Here, we used Jerusalem artichoke cultivar Nanyu 1 (NY-1) to characterise root distribution patterns and determine diversity and abundance of bacteria in the rhizosphere soil under variable salinity. Root growth was not inhibited within the salinity range 1.2 to 1.9 g salt/kg, but roots were mainly confined to 0-20 cm soil layer vertically and 0-30 cm horizontally from the plant centre. Root concentrations of K(+), Na(+), Mg(2+) and particularly Ca(2+) were relatively high under salinity stress. High salinity stress decreased soil invertase and catalase activity. Using a next-generation, Illumina-based sequencing approach, we determined higher diversity of bacteria in the rhizosphere soil at high than low salinity. More than 15,500 valid reads were obtained, and Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria predominated in all samples, accounting for >80% of the reads. On a genus level, 636 genera were common to the low and high salinity treatments at 0-5 cm and 5-10 cm depth. The abundance of Steroidobacter and Sphingomonas was significantly decreased by increasing salinity. Higher Shannon and Chao 1 indices with increasing severity of salt stress indicated that high salt stress increased diversity in the bacterial communities. PMID:26852800
Yang, Hui; Hu, Jinxiang; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed
The interaction between roots and bacterial communities in halophytic species is poorly understood. Here, we used Jerusalem artichoke cultivar Nanyu 1 (NY-1) to characterise root distribution patterns and determine diversity and abundance of bacteria in the rhizosphere soil under variable salinity. Root growth was not inhibited within the salinity range 1.2 to 1.9 g salt/kg, but roots were mainly confined to 0–20 cm soil layer vertically and 0–30 cm horizontally from the plant centre. Root concentrations of K+, Na+, Mg2+ and particularly Ca2+ were relatively high under salinity stress. High salinity stress decreased soil invertase and catalase activity. Using a next-generation, Illumina-based sequencing approach, we determined higher diversity of bacteria in the rhizosphere soil at high than low salinity. More than 15,500 valid reads were obtained, and Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria predominated in all samples, accounting for >80% of the reads. On a genus level, 636 genera were common to the low and high salinity treatments at 0–5 cm and 5–10 cm depth. The abundance of Steroidobacter and Sphingomonas was significantly decreased by increasing salinity. Higher Shannon and Chao 1 indices with increasing severity of salt stress indicated that high salt stress increased diversity in the bacterial communities. PMID:26852800
Franco Palla; Giovanna Barresi; Enza Di Carlo
The microscopic and molecular techniques described in this study are aimed at understanding the degradation processes of the anatomical structure of submerged archaeological wood, correlating it to the degradation induced by bacteria. The SEM micrographs showed alterations of the wooden structure due to bacterial colonization, as well as the presence of pyrite framboids. The difficulty of extracting bacterial DNA from wooden fragments belonging to submerged finds is well-known, due to the pre...
Full Text Available Abstract Background Feeding related peptides have been shown to be additionally involved in the central autonomic control of gastrointestinal functions. Recent studies have shown that ghrelin, a stomach-derived orexigenic peptide, is involved in the autonomic regulation of GI function besides feeding behavior. Pharmacological evidence indicates that ghrelin effects on food intake are mediated by neuropeptide Y in the central nervous system. Methods In the present study we examine the role of ghrelin in the central autonomic control of GI motility using intracerobroventricular and IP microinjections in a freely moving conscious rat model. Further the hypothesis that a functional relationship between NPY and ghrelin within the CNS exists was addressed. Results ICV injections of ghrelin (0.03 nmol, 0.3 nmol and 3.0 nmol/5 μl and saline controls decreased the colonic transit time up to 43%. IP injections of ghrelin (0.3 nmol – 3.0 nmol kg-1 BW and saline controls decreased colonic transit time dose related. Central administration of the NPY1 receptor antagonist, BIBP-3226, prior to centrally or peripherally administration of ghrelin antagonized the ghrelin induced stimulation of colonic transit. On the contrary ICV-pretreatment with the NPY2 receptor antagonist, BIIE-0246, failed to modulate the ghrelin induced stimulation of colonic motility. Conclusion The results suggest that ghrelin acts in the central nervous system to modulate gastrointestinal motor function utilizing NPY1 receptor dependent mechanisms.
Full Text Available Acquisition of the extracellular tetracycline (TC resistance plasmid pAST2 affected host gene expression and phenotype in the oil-degrading soil bacterium, Acinetobacter oleivorans DR1. Whole-transcriptome profiling of DR1 cells harboring pAST2 revealed that all the plasmid genes were highly expressed under TC conditions, and the expression levels of many host chromosomal genes were modulated by the presence of pAST2. The host energy burden imposed by replication of pAST2 led to (i lowered ATP concentrations, (ii downregulated expression of many genes involved in cellular growth, and (iii reduced growth rate. Interestingly, some phenotypes were restored by deleting the plasmid-encoded efflux pump gene tetH, suggesting that the membrane integrity changes resulting from the incorporation of efflux pump proteins also resulted in altered host response under the tested conditions. Alteration of membrane integrity by tetH deletion was shown by measuring permeability of fluorescent probe and membrane hydrophobicity. The presence of the plasmid conferred peroxide and superoxide resistance to cells, but only peroxide resistance was diminished by tetH gene deletion, suggesting that the plasmid-encoded membrane-bound efflux pump protein provided peroxide resistance. The downregulation of fimbriae-related genes presumably led to reduced swimming motility, but this phenotype was recovered by tetH gene deletion. Our data suggest that not only the plasmid replication burden, but also its encoded efflux pump protein altered host chromosomal gene expression and phenotype, which also alters the ecological fitness of the host in the environment.
Kosikowska, Urszula; Korona-Głowniak, Izabela; Niedzielski, Artur; Malm, Anna
Haemophili are pathogenic or opportunistic bacteria often colonizing the upper respiratory tract mucosa. The prevalence of Haemophilus influenzae (with serotypes distribution), and H. parainfluenzae in the nasopharynx and/or the adenoid core in children with recurrent pharyngotonsillitis undergoing adenoidectomy was assessed. Haemophili isolates were investigated for their ability to biofilm production.Nasopharyngeal swabs and the adenoid core were collected from 164 children who underwent adenoidectomy (2-5 years old). Bacteria were identified by the standard methods. Serotyping of H. influenzae was performed using polyclonal and monoclonal antisera. Biofilm formation was detected spectrophotometrically using 96-well microplates and 0.1% crystal violet.Ninety seven percent (159/164) children who underwent adenoidectomy were colonized by Haemophilus spp. The adenoid core was colonized in 99.4% (158/159) children, whereas the nasopharynx in 47.2% (75/159) children (P parainfluenzae and 14 isolates of other Haemophilus spp. were selected. In 20.1% (32/159) children 2 or 3 phenotypically different isolates of the same species (H. influenzae or H. parainfluenzae) or serotypes (H. influenzae) were identified in 1 child. 67.2% (129/192) isolates of H. influenzae, 56.3% (54/96) isolates of H. parainfluenzae and 85.7% (12/14) isolates of other Haemophilus spp. were positive for biofilm production. Statistically significant differences (P = 0.0029) among H. parainfluenzae biofilm producers and nonproducers in the adenoid core and the nasopharynx were detected.H. influenzae and H. parainfluenzae carriage rate was comparatively higher in the adenoid core than that in the nasopharynx in children undergoing adenoidectomy, suggesting that their involvement in chronic adenoiditis. The growth in the biofilm seems to be an important feature of haemophili colonizing the upper respiratory tract responsible for their persistence. PMID:25950686
Lokesh Kumar Booupathy
Full Text Available Colon cancer remains as a serious health problem around the world despite advances in diagnosis and treatment. Dietary fibers are considered to reduce the risk of colon cancer as they are converted to short chain fatty acids by the presence of anaerobic bacteria in the intestine, but imbalanced diet and high fat consumption may promote tumor formation at different sites, including the large bowel via increased bacterial enzymes activity. The present study was conducted to characterize the inhibitory action of myrtenal on bacterial enzymes and aberrant crypt foci (ACF. Experimental colon carcinogenesis induced by 1,2-dimethylhydrazine is histologically, morphologically, and anatomically similar to human colonic epithelial neoplasm. Discrete microscopic mucosal lesions such as ACF and malignant tumors function as important biomarkers in the diagnosis of colon cancer. Methylene blue staining was carried out to visualize the impact of 1,2-dimethylhydrazine and myrtenal. Myrtenal-treated animals showed decreased levels of bacterial enzymes such as β-glucuronidase, β-glucosidase, and mucinase. Characteristic changes in the colon were noticed by inhibiting ACF formation in the colon. In conclusion, treatment with myrtenal provided altered pathophysiological condition in colon cancer-bearing animals with evidence of decreased crypt multiplicity and tumor progression.
Robert D Kirkcaldy
Full Text Available Objectives. We investigated whether abnormal vaginal flora, including bacterial vaginosis (BV, are associated with detection of cervical HIV-1 RNA among HIV-infected women in Mozambique. Methods. We obtained clinical data and vaginal specimens from HIV-infected women registering for their first visit at one of two HIV care clinics in Mozambique. We compared women with detectable cervical HIV viral load (≥40 copies/ml with women with undetectable cervical HIV. Results. We enrolled 106 women. Women with abnormal vaginal flora (intermediate Nugent scores, 4 - 6 were more likely to have detectable cervical HIV RNA then women with normal vaginal flora (adjusted odds ratio 7.2 (95% confidence interval 1.8 - 29.1, adjusted for CD4 count. Women with BV had a non-significantly higher likelihood of detectable cervical HIV than women with normal flora. Conclusions. Abnormal vaginal flora were significantly associated with cervical HIV expression. Further research is needed to confirm this relationship.
Full Text Available Biofilms are microbial communities that adhere to biotic or abiotic surfaces and are enclosed in a protective matrix of extracellular compounds. An important advantage of the biofilm lifestyle for soil bacteria (rhizobacteria is protection against water deprivation (desiccation or osmotic effect. The rhizosphere is a crucial microhabitat for ecological, interactive, and agricultural production processes. The composition and functions of bacterial biofilms in soil microniches are poorly understood. We studied multibacterial communities established as biofilm-like structures in the rhizosphere of Medicago sativa (alfalfa exposed to 3 experimental conditions of water limitation. The whole biofilm-forming ability (WBFA for rhizospheric communities exposed to desiccation was higher than that of communities exposed to saline or nonstressful conditions. A culture-dependent ribotyping analysis indicated that communities exposed to desiccation or saline conditions were more diverse than those under the nonstressful condition. 16S rRNA gene sequencing of selected strains showed that the rhizospheric communities consisted primarily of members of the Actinobacteria and α- and γ-Proteobacteria, regardless of the water-limiting condition. Our findings contribute to improved understanding of the effects of environmental stress factors on plant-bacteria interaction processes and have potential application to agricultural management practices.
Full Text Available Qualitative and quantitative alterations in ileal flora during obstructive jaundice and the role of bile salts were evaluated in rats. Obstructive jaundice was associated with bacterial overgrowth in the ileum. This effect may be due to the reduced concentration of bile salts, since dietary supplementation reduced the small bowel aerobic bacterial flora.As alterações qualitativas e quantitativas da flora ileal na obstrução biliar e o papel dos sais biliares foram avaliados em ratos. Em animais com obstrução biliar houve aumento da população ileal. Esse efeito é provavelmente causado pela ausência de sais biliares no lúmen ileal, uma vez que em animais cuja dieta foi suplementada com sais biliares houve redução da flora ileal.
Nanoscale zerovalent iron (nZVI) has potential for the remediation of organochlorine-contaminated environments. Environmental safety concerns associated with in situ deployment of nZVI include potential negative impacts on indigenous microbes whose biodegradative functions could contribute to contaminant remediation. With respect to a two-step polychlorinated biphenyl remediation scenario comprising nZVI dechlorination followed by aerobic biodegradation, we examined the effect of polyacrylic acid (PAA)-coated nZVI (mean diameter = 12.5 nm) applied at 10 g nZVI kg−1 to Aroclor-1242 contaminated and uncontaminated soil over 28 days. nZVI had a limited effect on Aroclor congener profiles, but, either directly or indirectly via changes to soil physico-chemical conditions (pH, Eh), nZVI addition caused perturbation to soil bacterial community composition, and reduced the activity of chloroaromatic mineralizing microorganisms. We conclude that nZVI addition has the potential to inhibit microbial functions that could be important for PCB remediation strategies combining nZVI treatment and biodegradation. Highlights: ► Impact of nano-sized zerovalent iron on microbes was investigated in soil microcosms. ► Zerovalent iron had short-lived effects on redox potential and Aroclor dechlorination. ► Microbial populations also showed short-lived perturbations in their size. ► The activity of chloroaromatic degrading microbes did not recover within 28 days. ► Zerovalent iron application inhibits ensuing PCB bioremediative microbial functions. - nZVI inhibits microbial functions of potential importance for remediation strategies combining nZVI treatment and biodegradation.
Full Text Available Lipomas are benign soft tissue tumors derived from mature adipocytes. The colon is the most commonly involved organ in the entire gastrointestinal tract. Most gastrointestinal tract lipomas are asymptomatic and found incidentally during endoscopy, surgery or radiological examinations. In this video, we show the typical endoscopic findings of colonic lipomas.
Habib, Christophe; Houel, Armel; Lunazzi, Aurélie; Bernardet, Jean-François; Olsen, Anne Berit; Nilsen, Hanne; Toranzo, Alicia E.; Castro, Nuria; Nicolas, Pierre; Duchaud, Eric
The genus Tenacibaculum, a member of the family Flavobacteriaceae, is an abundant component of marine bacterial ecosystems that also hosts several fish pathogens, some of which are of serious concern for marine aquaculture. Here, we applied multilocus sequence analysis (MLSA) to 114 representatives of most known species in the genus and of the worldwide diversity of the major fish pathogen Tenacibaculum maritimum. Recombination hampers precise phylogenetic reconstruction, but the data indicat...
Thu Thuy Nguyen; Jeremie Guedj; Elisabeth Chachaty; Jean de Gunzburg; Antoine Andremont; France Mentré
Fecal excretion of antibiotics and resistant bacteria in the environment are major public health threats associated with extensive farming and modern medical care. Innovative strategies that can reduce the intestinal antibiotic concentrations during treatments are in development. However, the effect of lower exposure on the amount of resistant enterobacteria excreted has not been quantified, making it difficult to anticipate the impact of these strategies. Here, we introduce a bacterial kinet...
Nguyen, Thu Thuy; Guedj, Jeremie; Chachaty, Elisabeth; de Gunzburg, Jean; Andremont, Antoine; Mentré, France
Fecal excretion of antibiotics and resistant bacteria in the environment are major public health threats associated with extensive farming and modern medical care. Innovative strategies that can reduce the intestinal antibiotic concentrations during treatments are in development. However, the effect of lower exposure on the amount of resistant enterobacteria excreted has not been quantified, making it difficult to anticipate the impact of these strategies. Here, we introduce a bacterial kinet...
Adams, Aaron S.; Aylward, Frank O.; Adams, Sandye M; Erbilgin, Nadir; Aukema, Brian H.; Currie, Cameron R; Suen, Garret; Raffa, Kenneth F.
The mountain pine beetle, Dendroctonus ponderosae, is a subcortical herbivore native to western North America that can kill healthy conifers by overcoming host tree defenses, which consist largely of high terpene concentrations. The mechanisms by which these beetles contend with toxic compounds are not well understood. Here, we explore a component of the hypothesis that beetle-associated bacterial symbionts contribute to the ability of D. ponderosae to overcome tree defenses by assisting with...
Balbontín, Roberto; Vlamakis, Hera; Kolter, Roberto
Salmonella Typhimurium inhabits a variety of environments and is able to infect a broad range of hosts. Throughout its life cycle, some hosts can act as intermediates in the path to the infection of others. Aspergillus niger is a ubiquitous fungus that can often be found in soil or associated to plants and microbial consortia. Recently, S. Typhimurium was shown to establish biofilms on the hyphae of A. niger. In this work, we have found that this interaction is stable for weeks without a noticeable negative effect on either organism. Indeed, bacterial growth is promoted upon the establishment of the interaction. Moreover, bacterial biofilms protect the fungus from external insults such as the effects of the anti-fungal agent cycloheximide. Thus, the Salmonella-Aspergillus interaction can be defined as mutualistic. A tripartite gnotobiotic system involving the bacterium, the fungus and a plant revealed that co-colonization has a greater negative effect on plant growth than colonization by either organism in dividually. Strikingly, co-colonization also causes a reduction in plant invasion by S. Typhimurium. This work demonstrates that S. Typhimurium and A. niger establish a mutualistic interaction that alters bacterial colonization of plants and affects plant physiology. PMID:25351041
Adams, Aaron S; Aylward, Frank O; Adams, Sandye M; Erbilgin, Nadir; Aukema, Brian H; Currie, Cameron R; Suen, Garret; Raffa, Kenneth F
The mountain pine beetle, Dendroctonus ponderosae, is a subcortical herbivore native to western North America that can kill healthy conifers by overcoming host tree defenses, which consist largely of high terpene concentrations. The mechanisms by which these beetles contend with toxic compounds are not well understood. Here, we explore a component of the hypothesis that beetle-associated bacterial symbionts contribute to the ability of D. ponderosae to overcome tree defenses by assisting with terpene detoxification. Such symbionts may facilitate host tree transitions during range expansions currently being driven by climate change. For example, this insect has recently breached the historical geophysical barrier of the Canadian Rocky Mountains, providing access to näive tree hosts and unprecedented connectivity to eastern forests. We use culture-independent techniques to describe the bacterial community associated with D. ponderosae beetles and their galleries from their historical host, Pinus contorta, and their more recent host, hybrid P. contorta-Pinus banksiana. We show that these communities are enriched with genes involved in terpene degradation compared with other plant biomass-processing microbial communities. These pine beetle microbial communities are dominated by members of the genera Pseudomonas, Rahnella, Serratia, and Burkholderia, and the majority of genes involved in terpene degradation belong to these genera. Our work provides the first metagenome of bacterial communities associated with a bark beetle and is consistent with a potential microbial contribution to detoxification of tree defenses needed to survive the subcortical environment. PMID:23542624
Full Text Available The patina represents a superficial natural alteration of the constituting matter of the work of art. It emerges from the natural and usual stabilization process that the materials of the surface undergo because of the interaction with outdoor agents characterizing the surrounding environment. Besides, it is not linked to an obvious phenomenon of degradation that can be noticed through the change in the original colour of the matter. This is what we intend when we talk about biological patina usually generated by macro and/or micro-organic colonization (fungi, bacteria, alga which contributes to surface bio-deterioration and thus lead to the formation of orange, red or even brown and dark pigmented areas. The presence of chromatic alterations (rose-coloured areas, as a consequence of bacterial colonization, was most particularly pointed out in different sites, such as in the marble slabs on the facades of both the Cathedral of Siena (Duomo di Siena and the Certosa of Pavia. The present study shows an example of chromatic alteration of the surface of marble works due to bacterial colonization.
Ray, Debolina; Kidane, Dawit
Gut microbiota are required for host nutrition, energy balance, and regulating immune homeostasis, however, in some cases, this mutually beneficial relationship becomes twisted (dysbiosis), and the gut flora can incite pathological disorders including colon cancer. Microbial dysbiosis promotes the release of bacterial genotoxins, metabolites, and causes chronic inflammation, which promote oxidative DNA damage. Oxidized DNA base lesions are removed by base excision repair (BER), however, the role of this altered function of BER, as well as microbiota-mediated genomic instability and colon cancer development, is still poorly understood. In this review article, we will discuss how dysbiotic microbiota induce DNA damage, its impact on base excision repair capacity, the potential link of host BER gene polymorphism, and the risk of dysbiotic microbiota mediated genomic instability and colon cancer.
EGFR is frequently overexpressed in colon cancer. We characterized HT-29 and Caco-2, human colon cancer cell lines, untreated and treated with cetuximab or gefitinib alone and in combination with EGF. Cell growth was determined using a variation on the MTT assay. Cell-cycle analysis was conducted by flow cytometry. Immunohistochemistry was performed to evaluate EGFR expression and scanning electron microscopy (SEM) evidenced the ultrastructural morphology. Gene expression profiling was performed using hybridization of the microarray Ocimum Pan Human 40 K array A. Caco-2 and HT-29 were respectively 66.25 and 59.24 % in G0/G1. They maintained this level of cell cycle distribution after treatment, suggesting a predominantly differentiated state. Treatment of Caco-2 with EGF or the two EGFR inhibitors produced a significant reduction in their viability. SEM clearly showed morphological cellular transformations in the direction of cellular death in both cell lines treated with EGFR inhibitors. HT-29 and Caco-2 displayed an important reduction of the microvilli (which also lose their erect position in Caco-2), possibly invalidating microvilli absorption function. HT-29 treated with cetuximab lost their boundary contacts and showed filipodi; when treated with gefitinib, they showed some vesicles: generally membrane reshaping is evident. Both cell lines showed a similar behavior in terms of on/off switched genes upon treatment with cetuximab. The gefitinib global gene expression pattern was different for the 2 cell lines; gefitinib treatment induced more changes, but directly correlated with EGF treatment. In cetuximab or gefitinib plus EGF treatments there was possible summation of the morphological effects: cells seemed more weakly affected by the transformation towards apoptosis. The genes appeared to be less stimulated than for single drug cases. This is the first study to have systematically investigated the effect of cetuximab or gefitinib, alone and in combination
Polysaccharides extracted from the Phellinus linteus (PL) mushroom are known to possess anti-tumor effects. However, the molecular mechanisms responsible for the anti-tumor properties of PL remain to be explored. Experiments were carried out to unravel the anticancer effects of PL. The anti-cancer effects of PL were examined in SW480 colon cancer cells by evaluating cell proliferation, invasion and matrix metallo-proteinase (MMP) activity. The anti-angiogenic effects of PL were examined by assessing human umbilical vein endothelial cell (HUVEC) proliferation and capillary tube formation. The in vivo effect of PL was evaluated in an athymic nude mouse SW480 tumor engraft model. PL (125-1000 μg/mL) significantly inhibited cell proliferation and decreased β-catenin expression in SW480 cells. Expression of cyclin D1, one of the downstream-regulated genes of β-catenin, and T-cell factor/lymphocyte enhancer binding factor (TCF/LEF) transcription activity were also significantly reduced by PL treatment. PL inhibited in vitro invasion and motility as well as the activity of MMP-9. In addition, PL treatment inhibited HUVEC proliferation and capillary tube formation. Tumor growth of SW480 cells implanted into nude mice was significantly decreased as a consequence of PL treatment, and tumor tissues from treated animals showed an increase in the apoptotic index and a decrease in β-catenin expression. Moreover, the proliferation index and microvessel density were significantly decreased. These data suggest that PL suppresses tumor growth, invasion, and angiogenesis through the inhibition of Wnt/β-catenin signaling in certain colon cancer cells
Full Text Available Abstract Background Polysaccharides extracted from the Phellinus linteus (PL mushroom are known to possess anti-tumor effects. However, the molecular mechanisms responsible for the anti-tumor properties of PL remain to be explored. Experiments were carried out to unravel the anticancer effects of PL. Methods The anti-cancer effects of PL were examined in SW480 colon cancer cells by evaluating cell proliferation, invasion and matrix metallo-proteinase (MMP activity. The anti-angiogenic effects of PL were examined by assessing human umbilical vein endothelial cell (HUVEC proliferation and capillary tube formation. The in vivo effect of PL was evaluated in an athymic nude mouse SW480 tumor engraft model. Results PL (125-1000 μg/mL significantly inhibited cell proliferation and decreased β-catenin expression in SW480 cells. Expression of cyclin D1, one of the downstream-regulated genes of β-catenin, and T-cell factor/lymphocyte enhancer binding factor (TCF/LEF transcription activity were also significantly reduced by PL treatment. PL inhibited in vitro invasion and motility as well as the activity of MMP-9. In addition, PL treatment inhibited HUVEC proliferation and capillary tube formation. Tumor growth of SW480 cells implanted into nude mice was significantly decreased as a consequence of PL treatment, and tumor tissues from treated animals showed an increase in the apoptotic index and a decrease in β-catenin expression. Moreover, the proliferation index and microvessel density were significantly decreased. Conclusions These data suggest that PL suppresses tumor growth, invasion, and angiogenesis through the inhibition of Wnt/β-catenin signaling in certain colon cancer cells.
Tanaka, Yuriko; Ito, Sachiko; Isobe, Ken-Ichi
Inflammatory bowel disease confers an increased risk of developing colitis-associated colon cancer (CAC). During the active colitis or developing tumor stage, commensal bacteria show dynamic translocation. However, whether alteration of the bacterial composition in the gut causes CAC is still unclear. To clarify the effect of commensal bacteria on CAC development, we employed an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced murine CAC model treated with or without antibiotics. In addition, we analyzed the effects of antibiotics on infiltration of myeloid cells, colonic inflammatory responses, and colorectal cancer formation. We found that vancomycin treatment dramatically suppressed tumor development. In addition, AOM/DSS treatment greatly induced the infiltration of Gr-1(high)/CD11b(high) neutrophils to the colon, which led to the production of tumor necrosis factor α and inducible nitric oxide synthase. Vancomycin treatment suppressed the infiltration of neutrophils induced by AOM/DSS. Moreover, vancomycin treatment greatly reduced the colon injury and DNA damage caused by AOM/DSS-induced NO radicals. Our results indicate that vancomycin-sensitive bacteria induced colon inflammation and DNA damage by attracting neutrophils into damaged colon tissue, thus promoting tumor formation. PMID:27050089
He, Xuesong; McLean, Jeffrey S.; Guo, Lihong; Lux, Renate; Shi, Wenyuan
It is well established that host-associated microbial communities can interfere with the colonization and establishment of microbes of foreign origins, a phenomenon often referred to as bacterial interference or colonization resistance. However, due to the complexity of the indigenous microbiota, it has been extremely difficult to elucidate the community colonization resistance mechanisms and identify the bacterial species involved. In a recent study, we have established an in vitro mice oral...
Hadrontherapy is an advanced form of radiotherapy that uses beams of charged particles (such as protons and carbon ions). Compared with conventional radiotherapy, the main advantages of carbon ion therapy are the precise absorbed dose localization, along with an increased relative biological effectiveness (RBE). This high ballistic accuracy of particle beams deposits the maximal dose to the tumor, while damage to the surrounding healthy tissue is limited. Currently, hadrontherapy is being used for the treatment of specific types of cancer. Previous in vitro studies have shown that, under certain circumstances, exposure to charged particles may inhibit cell motility and migration. In the present study, we investigated the expression of four motility-related genes in prostate (PC3) and colon (Caco-2) cancer cell lines after exposure to different radiation types. Cells were irradiated with various absorbed doses (0, 0.5 and 2 Gy) of accelerated 13C-ions at the GANIL facility (Caen, France) or with X-rays. Clonogenic assays were performed to determine the RBE. RT-qPCR analysis showed dose- and time-dependent changes in the expression of CCDC88A, FN1, MYH9 and ROCK1 in both cell lines. However, whereas in PC3 cells the response to carbon ion irradiation was enhanced compared with X-irradiation, the effect was the opposite in Caco-2 cells, indicating cell-type–specific responses to the different radiation types. (author)
马艳; 张欢; 李芳
目的：对新生儿脐部感染细菌定植进行分析研究，以减少新生儿脐部感染率。方法选取2012年3月－2013年3月接收的225例新生儿作为研究对象，随机将其分为干预组114例和对照组111例；对照组采用常规的脐部护理，干预组则采用脐部干预措施，对比两组新生儿脐部细菌感染率及细菌定植率，并探讨新生儿脐部感染的相关因素。结果225例新生儿发生脐部感染45例，感染率为20．0％；观察组感染率为10．5％，对照组为29．7％，两组新生儿脐部感染率比较差异有统计学意义（ P＜0．05）；干预组和对照组的细菌定植率分别为95．6％和92．8％，两组比较差异无统计学意义；而两组新生儿病原菌的感染率只有大肠埃希菌的感染率差异有统计学意义（P＜0．05），其他病原菌的感染率差异无统计学意义；脐部感染的原因以脐端消毒不严所致的感染率最高，为55．0％；其次是脐带结扎位置及脐带修剪不净，感染率分别为22．6％和22．2％。结论新生儿脐部是细菌定植的好发部位，因此需要做好新生儿的脐部护理，减少脐部感染的发生。%OBJECTIVE To study the bacterial colonization in neonates with umbilical infections so as to reduce the incidence of umbilical infections in the neonates .METHODS A total of 225 neonates who were enrolled in the hos‐pital from Mar 2012 to Mar 2013 were recruited as the study objects and randomly divided into the intervention group with 114 cases and the control group with 111 cases .The control group was treated with conventional um‐bilical nursing ,while the intervention group was given the umbilical interventions .The incidence of umbilical infec‐tions and the rate of bacterial colonization in neonates were compared between the two groups ,and the related fac‐tors for the umbilical infections in the neonates were explored .RESULTS The umbilical infections
Habib, Christophe; Houel, Armel; Lunazzi, Aurélie; Bernardet, Jean-François; Olsen, Anne Berit; Nilsen, Hanne; Toranzo, Alicia E; Castro, Nuria; Nicolas, Pierre; Duchaud, Eric
The genus Tenacibaculum, a member of the family Flavobacteriaceae, is an abundant component of marine bacterial ecosystems that also hosts several fish pathogens, some of which are of serious concern for marine aquaculture. Here, we applied multilocus sequence analysis (MLSA) to 114 representatives of most known species in the genus and of the worldwide diversity of the major fish pathogen Tenacibaculum maritimum. Recombination hampers precise phylogenetic reconstruction, but the data indicate intertwined environmental and pathogenic lineages, which suggests that pathogenicity evolved independently in several species. At lower phylogenetic levels recombination is also important, and the species T. maritimum constitutes a cohesive group of isolates. Importantly, the data reveal no trace of long-distance dissemination that could be linked to international fish movements. Instead, the high number of distinct genotypes suggests an endemic distribution of strains. The MLSA scheme and the data described in this study will help in monitoring Tenacibaculum infections in marine aquaculture; we show, for instance, that isolates from tenacibaculosis outbreaks in Norwegian salmon farms are related to T. dicentrarchi, a recently described species. PMID:24973065
Holmes, Paul E.
The role of bacteria in the development of algae on low-density vinyl was investigated. Unidentified bacterial contaminants in unialgal stock cultures of Phormidium faveolarum and Pleurochloris pyrenoidosa enhanced, by 1 to 2 orders of magnitude, colonization of vinyl by these algae, as determined by epifluorescence microscopy counts and chlorophyll a in extracts of colonized vinyl. Colonization by bacteria always preceded that by algae. Scanning electron microscopy of the colonized Phormidiu...
Gueugnon, Fabien; Thibault, Virginie C; Kearley, Jennifer; Petit-Courty, Agnès; Vallet, Amandine; Guillon, Antoine; Si-Tahar, Mustapha; Humbles, Alison A; Courty, Yves
The CCN proteins are key signaling and regulatory molecules involved in many biological functions and contribute to malignant and non-malignant lung diseases. Despite the high morbidity and mortality of the lung respiratory infectious diseases, there is very little data related to the expression of the CCNs during infection. We investigated in mice the pulmonary mRNA expression levels of five CCNs (1 to 5) in response to influenza A virus (IAV) and bacterial agents (Nontypeable Haemophilus influenzae (NTHi), lipopolysaccharide (LPS) and lipoteichoic acid (LTA)). IAV, NTHi, LPS or LTA were instilled intranasally into mice. Mice were also exposed for 4days or 8weeks to cigarette smoke alone or prior infection to IAV in order to determine if CS modifies the CCN response to a viral infection. All challenges induced a robust inflammation. The mRNA expression of CCN1, CCN2 and CCN3 was decreased after short exposure to CS whereas prolonged exposure altered the expression of CCN1, CCN3 and CCN4. Influenza A virus infection increased CCN1, 2, 4 and 5 mRNA levels but expression of CCN3 was significantly decreased. Acute CS exposure prior infection had little effect on the expression of CCN genes but prolonged exposure abolished the IAV-dependent induction. Treatment with LPS or LTA and infection with NTHi revealed that both Gram-positive and Gram-negative bacteria rapidly modulate the expression of the CCN genes. Our findings reveal that several triggers of lung inflammation influence differently the CCN genes. CCN3 deserves special attention since its mRNA expression is decreased by all the triggers studied. PMID:27080955
Romero Herrero, Daniel; Andreu Domingo, Antonia
Bacterial vaginosis (BV) is the main cause of vaginal dysbacteriosis in the women during the reproductive age. It is an entity in which many studies have focused for years and which is still open for discussion topics. This is due to the diversity of microorganisms that cause it and therefore, its difficult treatment. Bacterial vaginosis is probably the result of vaginal colonization by complex bacterial communities, many of them non-cultivable and with interdependent metabolism where anaerobic populations most likely play an important role in its pathogenesis. The main symptoms are an increase of vaginal discharge and the unpleasant smell of it. It can lead to serious consequences for women, such as an increased risk of contracting sexually transmitted infections including human immunodeficiency virus and upper genital tract and pregnancy complications. Gram stain is the gold standard for microbiological diagnosis of BV, but can also be diagnosed using the Amsel clinical criteria. It should not be considered a sexually transmitted disease but it is highly related to sex. Recurrence is the main problem of medical treatment. Apart from BV, there are other dysbacteriosis less characterized like aerobic vaginitis of which further studies are coming slowly but are achieving more attention and consensus among specialists. PMID:27474242
Microflora of fruit surfaces has been the best source of antagonists against fungi causing postharvest decays of fruit. However, there is little information on microflora colonizing surfaces of fruits other than grapes, apples, and citrus fruit. We characterized bacterial microflora on nectarine f...
In this podcast, Dr. Tom Frieden, CDC Director, discusses colon cancer and the importance of early detection. Created: 11/5/2013 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP). Date Released: 3/6/2014.
Full Text Available ... cat scan that yields three-dimensional images. Your physician can examine the lining of the bowel directly ... altered colon cell DNA, in your stools. Your doctor will give you one of a variety of ...
Full Text Available ... Fecal occult blood test Fecal immunochemical test Stool DNA test Tests that prevent cancer: These tests examine ... of blood or cancerous material, altered colon cell DNA, in your stools. Your doctor will give you ...
Full Text Available ... These tests detect tiny amounts of blood or cells that are shed by large polyps or early ... traces of blood or cancerous material, altered colon cell DNA, in your stools. Your doctor will give ...
Averill, C.; Hawkes, C. V.; Waring, B. G.
Most biogeochemical models of soil carbon and nitrogen cycling include a simplified representation of the soil microbial community as a single pool, despite good evidence that shifts in the composition or relative abundance of microbial taxa can affect process rates. Incorporating a more realistic depiction of the microbial community in these models may increase their predictive accuracy, but this must be balanced against the feasibility of modeling the enormous diversity present in soil. We propose that explicitly including two major microbial functional groups with distinct physiologies, fungi and bacteria, will improve model predictions. To this end, we created the fungi and bacteria (FAB) model, building off previous enzyme-driven biogeochemical models that explicitly represent microbial physiology. We compared this model to a complementary biogeochemical model that does not include microbial community structure (';single-pool'). We also performed a cross-ecosystem meta-analysis of fungi-to-bacteria ratios to determine if model predictions of community structure matched empirical data. There were large differences in process rates and pool sizes between the single-pool and FAB models. In the FAB model, inorganic N pools were reduced by 5-95% depending on the soil C:N ratio due to bacterial immobilization of fungal mineralization products. This nitrogen subsidy also increased microbial biomass at some C:N ratios. Although there were changes in some components of respiration, particularly overflow respiration, there was no net effect of community structure on total respiration fluxes. The FAB model predicted a breakpoint in the relationship between the ratio of fungi to bacteria and soil C:N, after which the fungi-to-bacteria ratio should begin to increase. Break-point analysis of the meta-analysis data set revealed a consistent pattern and matched the slope of the change in F:B with soil C:N, but not the precise breakpoint. We argue that including microbial
Full Text Available OBJECTIVES: Ulcerative colitis (UC is a relapsing inflammatory disorder of unconfirmed aetiology, variable severity and clinical course, characterised by progressive histological inflammation and with elevation of eicosanoids which have a known pathophysiological role in inflammation. Therapeutic interventions targetting eicosanoids (5-aminosalicylates (ASA are effective first line and adjunctive treatments in mild-moderate UC for achieving and sustaining clinical remission. However, the variable clinical response to 5-ASA and frequent deterioration in response to cyclo-oxygenase (COX inhibitors, has prompted an in depth simultaneous evaluation of multiple lipid mediators (including eicosanoids within the inflammatory milieu in UC. We hypothesised that severity of inflammation is associated with alteration of lipid mediators, in relapsing UC. DESIGN: Study was case-control design. Mucosal lipid mediators were determined by LC-MS/MS lipidomics analysis on mucosal biopsies taken from patients attending outpatients with relapsing UC. Univariate and multivariate statistical analyses were used to investigate the association of mucosal lipid mediators, with the disease state and severity graded histologically. RESULTS: Levels of PGE2, PGD2, TXB2, 5-HETE, 11-HETE, 12-HETE and 15-HETE are significantly elevated in inflamed mucosa and correlate with severity of inflammation, determined using validated histological scoring systems. CONCLUSIONS: Our approach of capturing inflammatory mediator signature at different stages of UC by combining comprehensive lipidomics analysis and computational modelling could be used to classify and predict mild-moderate inflammation; however, predictive index is diminished in severe inflammation. This new technical approach could be developed to tailor drug treatments to patients with active UC, based on the mucosal lipid mediator profile.
Stokholm, J; Schjørring, S; Eskildsen, C E; Pedersen, L; Bischoff, A L; Følsgaard, N; Carson, C G; Chawes, B L K; Bønnelykke, K; Mølgaard, A; Jacobsson, B; Krogfelt, K A; Bisgaard, H
Antibiotics may induce alterations in the commensal microbiota of the birth canal in pregnant women. Therefore, we studied the effect of antibiotic administration during pregnancy on commensal vaginal bacterial colonization at gestational week 36. Six hundred and sixty-eight pregnant women from the novel unselected Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010 ) pregnancy cohort participated in this analysis. Detailed information on oral antibiotic prescriptions during pregnancy filled at the pharmacy was obtained and verified prospectively. Vaginal samples were obtained at pregnancy week 36 and cultured for bacteria. Women who received oral antibiotics during any pregnancy trimester had an increased rate of colonization by Staphylococcus species in the vaginal samples as compared with samples obtained from women without any antibiotic treatment during pregnancy (adjusted OR 1.63, 95% CI 1.06-2.52, p 0.028). Oral antibiotic administration in the third trimester were also associated with increased colonization by Staphylococcus species (adjusted OR 1.98, 95% CI 1.04-3.76, p 0.037). These bacteriological changes were associated with urinary tract infection antibiotics. Women treated in the third trimester of pregnancy were more often colonized by Escherichia coli than women without antibiotic treatment in the third trimester (adjusted OR 1.91, 95% CI 1.04-3.52, p 0.038). This change was associated with respiratory tract infection (RTI) antibiotics. We did not observe any significant changes in vaginal Streptococcus agalactiae (group B streptoccocus) or Staphylococcus aureus colonization following antibiotic treatment in pregnancy. Antibiotic administration during pregnancy leads to alterations in the vaginal microbiological ecology prior to birth, with potential morbidity, and long-term effects on the early microbial colonization of the neonate. PMID:24118384
Full Text Available Dissolved organic carbon (DOC concentrations – mainly of terrestrial origin – are increasing worldwide in inland waters. The biodegradability of the DOC varies depending on quantity and chemical quality. Heterotrophic bacteria are the main consumers of DOC and thus determine DOC temporal dynamics and availability for higher trophic levels. It is therefore crucial to understand the processes controlling the bacterial turnover of additional allochthonous and autochthonous DOC in aquatic systems. Our aim was to study bacterial carbon (C turnover with respect to DOC quantity and chemical quality using both allochthonous and autochthonous DOC sources. We incubated a natural bacterial community with allochthonous C (13C-labeled beech leachate and increased concentrations and pulses (intermittent occurrence of organic matter input of autochthonous C (algae lysate. We then determined bacterial carbon consumption, activities, and community composition together with the carbon flow through bacteria using stable C isotopes. The chemical analysis of single sources revealed differences in aromaticity and fractions of low and high molecular weight substances (LMWS and HMWS, respectively between allochthonous and autochthonous C sources. In parallel to these differences in chemical composition, we observed a higher availability of allochthonous C as evidenced by increased DOC consumption and bacterial growth efficiencies (BGE when solely allochthonous C was provided. In treatments with mixed sources, rising concentrations of added autochthonous DOC resulted in a further, significant increase in bacterial DOC consumption from 52 to 68% when nutrients were not limiting. This rise was accompanied by a decrease in the humic substances (HS fraction and an increase in bacterial biomass. Stable C isotope analyses of phospholipid fatty acids (PLFA and respired dissolved inorganic carbon (DIC supported a preferential assimilation of autochthonous C and respiration
Full Text Available New DNA sequencing technologies have emerged in the last decade enabling in-depth study of human gut microbiota. The bacterial communities inhabiting the gut influence our immune development and maturation with consequences for general health. However, the balance between host and bacterial community is affected by changes in lifestyle. Increasing rates of caesarean delivery, formula-feeding, antibiotic treatments, high fat diet, urbanization and hygiene have led to important changes in the colonization of the gut microbiota. Emergent diseases and conditions including asthma, allergies, autoimmunity, necrotizing enterocolitis (NEC, obesity and type I diabetes may be related to modifications in the microbiota. In this review we focus on studies related to early bacterial colonization of the gut, and how the evolution of gut microbiota during the first years of life may lead to new perspectives on the treatment of these diseases. Diet complementation with pre- or probiotics in formula or replacement of a disease associated-microbiota with a healthy one are currently the most studied approaches in the treatment of microbiota-related disorders. Bacteriophages may provide an alternative means for manipulating gut bacterial communities. However, the question is whether we can alter infant gut microbiota without any risk to health. High-throughput sequencing (HTS techniques give access to the composition of the gut microbiome, and its evolution over time or in response to different circumstances. This review discusses these techniques, evaluates the impact of microbiome composition on infant development and outlines possible improvements in health care based on this knowledge.