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Sample records for lactobacilli inhibit gonococci

  1. Lactobacilli Reduce Helicobacter pylori Attachment to Host Gastric Epithelial Cells by Inhibiting Adhesion Gene Expression

    PubMed Central

    de Klerk, Nele; Maudsdotter, Lisa; Gebreegziabher, Hanna; Saroj, Sunil D.; Eriksson, Beatrice; Eriksson, Olaspers Sara; Roos, Stefan; Lindén, Sara; Sjölinder, Hong

    2016-01-01

    The human gastrointestinal tract, including the harsh environment of the stomach, harbors a large variety of bacteria, of which Lactobacillus species are prominent members. The molecular mechanisms by which species of lactobacilli interfere with pathogen colonization are not fully characterized. In this study, we aimed to study the effect of lactobacillus strains upon the initial attachment of Helicobacter pylori to host cells. Here we report a novel mechanism by which lactobacilli inhibit adherence of the gastric pathogen H. pylori. In a screen with Lactobacillus isolates, we found that only a few could reduce adherence of H. pylori to gastric epithelial cells. Decreased attachment was not due to competition for space or to lactobacillus-mediated killing of the pathogen. Instead, we show that lactobacilli act on H. pylori directly by an effector molecule that is released into the medium. This effector molecule acts on H. pylori by inhibiting expression of the adhesin-encoding gene sabA. Finally, we verified that inhibitory lactobacilli reduced H. pylori colonization in an in vivo model. In conclusion, certain Lactobacillus strains affect pathogen adherence by inhibiting sabA expression and thereby reducing H. pylori binding capacity. PMID:26930708

  2. Lactobacilli Reduce Helicobacter pylori Attachment to Host Gastric Epithelial Cells by Inhibiting Adhesion Gene Expression.

    PubMed

    de Klerk, Nele; Maudsdotter, Lisa; Gebreegziabher, Hanna; Saroj, Sunil D; Eriksson, Beatrice; Eriksson, Olaspers Sara; Roos, Stefan; Lindén, Sara; Sjölinder, Hong; Jonsson, Ann-Beth

    2016-05-01

    The human gastrointestinal tract, including the harsh environment of the stomach, harbors a large variety of bacteria, of which Lactobacillus species are prominent members. The molecular mechanisms by which species of lactobacilli interfere with pathogen colonization are not fully characterized. In this study, we aimed to study the effect of lactobacillus strains upon the initial attachment of Helicobacter pylori to host cells. Here we report a novel mechanism by which lactobacilli inhibit adherence of the gastric pathogen H. pylori In a screen with Lactobacillus isolates, we found that only a few could reduce adherence of H. pylori to gastric epithelial cells. Decreased attachment was not due to competition for space or to lactobacillus-mediated killing of the pathogen. Instead, we show that lactobacilli act on H. pylori directly by an effector molecule that is released into the medium. This effector molecule acts on H. pylori by inhibiting expression of the adhesin-encoding gene sabA Finally, we verified that inhibitory lactobacilli reduced H. pylori colonization in an in vivo model. In conclusion, certain Lactobacillus strains affect pathogen adherence by inhibiting sabA expression and thereby reducing H. pylori binding capacity.

  3. Attachment and ingestion of gonococci human neutrophils.

    PubMed

    Dilworth, J A; Hendley, J O; Mandell, G L

    1975-03-01

    Previous studies have indirectly shown that type 1 gonococci are more resistant to phagocytosis by human neutrophils (PMN) than type 3 gonococci. Using phase contrast, fluorescent, and light microscopy, we directly quantitated PMN-gonococcal interaction, with emphasis on separating ingestion from attachment. PMN monolayers were incubated on slides with type 1 or type 3 gonococcal fluorescent antibody (FA). After methanol fixation, the FA-stained gonococci associated with PMN were cointed. Since the live PMN excludes FA, the FA-stained gonococci represent only extracellular gonococci. Methylene blue was then added to the smae slide to stain both ingested and surface attached gonococci. Using these methods, intracellular and extracellular cell-associated gonococci were quantitated under varying conditions. The numbers of methylene blue-stained cell-associated gonococci that were ingested were: with normal serum, 3.7 plus or minus 4.1 per cent for type 1 and 56.2 plus or minus 3.7 percent for type 3 (P smaller than 0.001); with heat-inactivated serum, 1.0 plus or minus 3.0 per cent for type 1 and 52.6 plus or minus 3.7 per cent for type 3 (P smaller than 0.001); with higher-titer anti-gonococcal antibody serum, 4.8 plus or minus 4.3 percent for type 1 and 64.0 plus or minus 1.6 per cent for type 3 (P smaller than 0.001). Thus, most type 3 organisms were ingested, but most type 1 gonococci were bound on the PMN surface.

  4. Attachment and ingestion of gonococci human neutrophils.

    PubMed Central

    Dilworth, J A; Hendley, J O; Mandell, G L

    1975-01-01

    Previous studies have indirectly shown that type 1 gonococci are more resistant to phagocytosis by human neutrophils (PMN) than type 3 gonococci. Using phase contrast, fluorescent, and light microscopy, we directly quantitated PMN-gonococcal interaction, with emphasis on separating ingestion from attachment. PMN monolayers were incubated on slides with type 1 or type 3 gonococcal fluorescent antibody (FA). After methanol fixation, the FA-stained gonococci associated with PMN were cointed. Since the live PMN excludes FA, the FA-stained gonococci represent only extracellular gonococci. Methylene blue was then added to the smae slide to stain both ingested and surface attached gonococci. Using these methods, intracellular and extracellular cell-associated gonococci were quantitated under varying conditions. The numbers of methylene blue-stained cell-associated gonococci that were ingested were: with normal serum, 3.7 plus or minus 4.1 per cent for type 1 and 56.2 plus or minus 3.7 percent for type 3 (P smaller than 0.001); with heat-inactivated serum, 1.0 plus or minus 3.0 per cent for type 1 and 52.6 plus or minus 3.7 per cent for type 3 (P smaller than 0.001); with higher-titer anti-gonococcal antibody serum, 4.8 plus or minus 4.3 percent for type 1 and 64.0 plus or minus 1.6 per cent for type 3 (P smaller than 0.001). Thus, most type 3 organisms were ingested, but most type 1 gonococci were bound on the PMN surface. Images PMID:46842

  5. Bacteriocins and other bioactive substances of probiotic lactobacilli as biological weapons against Neisseria gonorrhoeae.

    PubMed

    Ruíz, Francisco O; Pascual, Liliana; Giordano, Walter; Barberis, Lucila

    2015-04-01

    In the search of new antimicrobial agents against Neisseria gonorrhoeae, the bacteriocins-producing probiotic lactobacilli deserve special attention. The inhibitory effects of biosubstances such as organic acids, hydrogen peroxide and each bacteriocin-like inhibitory substance (BLIS) L23 and L60 on the growth of different gonococcal strains were investigated. Different non-treated and treated cell-free supernatants of two probiotic lactobacilli containing these metabolites were used. The aims of this work were (i) to evaluate the antimicrobial activity of the biosubstances produced by two probiotic lactobacilli, estimating the proportion in which each of them is responsible for the inhibitory effect, (ii) to define their minimum inhibitory concentrations (MICs) and, (iii) to determine the potential interactions between these biosubstances against N. gonorrhoeae. The main antimicrobial metabolites were the BLIS-es L23 and L60 in comparison with other biosubstances. Proportionally, their contributions to the inhibition on the gonococcal growth were 87.28% and 80.66%, respectively. The MIC values of bacteriocins were promising since these substances, when diluted, showed considerable inhibitory activity for all gonococci. In the interaction between bacteriocins, 100% of synergism was found on the gonococcal growth. In summary, this study indicates that both L23 and L60 could potentially serve to design new bioproducts against N. gonorrhoeae.

  6. [Lactobacilli and colon carcinoma--A review].

    PubMed

    Wang, Shumei; Zhang, Lanwei; Shan, Yujuan

    2015-06-04

    Epidemiological studies showed that incidence of colon carcinoma is increased in the world. There are many difficulties to inhibit colon carcinoma because the causes of inducing colon carcinoma were various and interactive each other. Previous evidence supported the balance of the colonic microflora was critical in inhibiting colon carcinoma and the protection by colonic microflora could be improved by ingesting lactobacilli. Therefore, the biological functions and anticancer effects of lactobacilli attract attention of researchers. In this review we discussed the causes of colon carcinoma; the anticancer mechanisms of lactobacilli on the basis of our own studies. Eventually, we summarized the effects of anticancer of different components and metabolic products extracted from lactobacilli.

  7. Probiotic lactobacilli inhibit early stages of Candida albicans biofilm development by reducing their growth, cell adhesion, and filamentation.

    PubMed

    Matsubara, Victor Haruo; Wang, Yi; Bandara, H M H N; Mayer, Marcia Pinto Alves; Samaranayake, Lakshman P

    2016-07-01

    We evaluated the inhibitory effects of the probiotic Lactobacillus species on different phases of Candida albicans biofilm development. Quantification of biofilm growth and ultrastructural analyses were performed on C. albicans biofilms treated with Lactobacillus rhamnosus, Lactobacillus casei, and Lactobacillus acidophilus planktonic cell suspensions as well as their supernatants. Planktonic lactobacilli induced a significant reduction (p < 0.05) in the number of biofilm cells (25.5-61.8 %) depending on the probiotic strain and the biofilm phase. L. rhamnosus supernatants had no significant effect on the mature biofilm (p > 0.05), but significantly reduced the early stages of Candida biofilm formation (p < 0.01). Microscopic analyses revealed that L. rhamnosus suspensions reduced Candida hyphal differentiation, leading to a predominance of budding growth. All lactobacilli negatively impacted C. albicans yeast-to-hyphae differentiation and biofilm formation. The inhibitory effects of the probiotic Lactobacillus on C. albicans entailed both cell-cell interactions and secretion of exometabolites that may impact on pathogenic attributes associated with C. albicans colonization on host surfaces and yeast filamentation. This study clarifies, for the first time, the mechanics of how Lactobacillus species may antagonize C. albicans host colonization. Our data elucidate the inhibitory mechanisms that define the probiotic candicidal activity of lactobacilli, thus supporting their utility as an adjunctive therapeutic mode against mucosal candidal infections.

  8. Fimbriae and lipopolysaccharides are necessary for co-aggregation between Lactobacilli and Escherichia coli.

    PubMed

    Mizuno, Kouhei; Furukawa, Soichi; Usui, Yumi; Ishiba, Madoka; Ogihara, Hirokazu; Morinaga, Yasushi

    2014-01-01

    Cells of Lactobacilli co-aggregated with Escherichia coli K-12 cells to form co-aggregates under mixed-culture conditions at 37 °C for 24 h. Co-aggregation was inhibited by sodium dodecyl sulfate but not by protease. E. coli deletion mutants of fimbriae formation and lipopolysaccharide (LPS) formation did not co-aggregate with Lactobacilli. These results showed that fimbriae and LPS are necessary for co-aggregation between Lactobacilli and E. coli.

  9. Lactobacilli as multifaceted probiotics with poorly disclosed molecular mechanisms.

    PubMed

    Turpin, Williams; Humblot, Christèle; Thomas, Muriel; Guyot, Jean-Pierre

    2010-10-15

    inhibited by probiotics. They can reinforce the intestinal barrier, simply occupying the ecological niche, or they can have an active role by synthesizing various metabolites inhibiting pathogen development. Lactobacilli have a long standing history with foods and humans but comparatively, their history as probiotics is recent. Their effects are investigated in in vitro and in vivo models leading sometimes to contradictory or controversial results that make necessary final demonstrations through clinical trials. Researches on molecular mechanisms involved in the beneficial effects reviewed here are necessary for a better understanding of these effects, but could also lead to the development of molecular tools to help the screening of the probiotic potential of lactobacilli that are common inhabitants of numerous fermented foods around the world.

  10. Oral Lactobacilli and Dental Caries

    PubMed Central

    Caufield, P.W.; Schön, C.N.; Saraithong, P.; Li, Y.; Argimón, S.

    2015-01-01

    Lactobacilli have been associated with dental caries for over a century. Here, we review the pertinent literature along with findings from our own study to formulate a working hypothesis about the natural history and role of lactobacilli. Unlike most indigenous microbes that stably colonize a host, lactobacilli appear to be planktonic, opportunistic settlers that can gather and multiply only in certain restrictive niches of the host, at least within the oral cavity. We postulate that the following essential requirements are necessary for sustained colonization of lactobacilli in humans: 1) a stagnant, retentive niche that is mostly anaerobic; 2) a low pH milieu; and 3) ready access to carbohydrates. Three sites on the human body meet these specifications: caries lesions, the stomach, and the vagina. Only a handful of Lactobacillus species is found in caries lesions, but they are largely absent in caries-free children. Lactobacilli present in caries lesions represent both a major contributor to caries progression and a major reservoir to the gastrointestinal (GI) tract. We extend the assertion from other investigators that lactobacilli found in the GI tract originate in the oral cavity by proposing that lactobacilli in the oral cavity arise from caries lesions. This, in turn, leads us to reflect on the health implications of the lactobacilli in the mouth and downstream GI and to ponder whether these or any of the Lactobacillus species are truly indigenous to the human GI tract or the oral cavity. PMID:25758458

  11. Genetic Resistance Determinants for Cefixime and Molecular Analysis of Gonococci Isolated in Italy.

    PubMed

    Carannante, Anna; Vacca, Paola; Ghisetti, Valeria; Latino, Maria Agnese; Cusini, Marco; Matteelli, Alberto; Vocale, Caterina; Prignano, Grazia; Leli, Christian; Ober, Patrizia; Antonetti, Raffaele; Poletti, Federica; Stefanelli, Paola

    2017-03-01

    A strictly defined subset of gonococci (n = 65) isolated in Italy from 2011 to 2014 was characterized by antimicrobial susceptibility for cefixime (CFM) and ceftriaxone (CRO) and by sequencing of resistance determinant genes (penA, mtrR, porB1b, ponA) for extended-spectrum cephalosporins and Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST). The penA mosaic alleles XXXIV and XXXV were found in all resistant (R) and decreased susceptibility (DS) gonococci to CFM, except for one. They were associated with an adenine deletion in the mtrR promoter plus amino acid substitutions, H105Y or G45D, in the coding region and ponA L421P. The penA mosaic allele XXXIV, and one variant, was found exclusively among genogroup (G) 1407 and its closely related sequence types (STs), as in CFM-DS as well as in CFM-R isolates. Single or combined mutation patterns in penA, mtrR, porB1b, and ponA genes were associated with different CFM susceptibility patterns and NG-MAST STs. Genotyping and antimicrobial resistance (AMR) determinant analyses can be valuable to enhance the gonococcal AMR surveillance.

  12. Lactobacilli Reduce Chemokine IL-8 Production in Response to TNF-α and Salmonella Challenge of Caco-2 Cells

    PubMed Central

    Ren, Da-Yong; Li, Chang; Qin, Yan-Qing; Yin, Rong-Lan; Du, Shou-Wen; Ye, Fei; Liu, Hong-Feng; Wang, Mao-Peng; Sun, Yang; Li, Xiao; Tian, Ming-Yao; Jin, Ning-Yi

    2013-01-01

    The probiotic properties of two selected lactobacilli strains were assessed. L. salivarius and L. plantarum displayed higher hydrophobicity (48% and 54%, resp.) and coaggregation ability with four pathogens (from 7.9% to 57.5%). L. salivarius and L. plantarum had good inhibitory effects on S. aureus (38.2% and 49.5%, resp.) attachment to Caco-2 cells. Live lactobacilli strains and their conditioned media effectively inhibited IL-8 production (<14.6 pg/mL) in TNF-α-induced Caco-2 cells. Antibiotic-treated and the sonicated lactobacilli also maintained inhibitory effects (IL-8 production from 5.0 to 36.3 pg/mL); however, the heat-treated lactobacilli lost their inhibitory effects (IL-8 production from 130.2 to 161.0 pg/mL). These results suggest that both the structural components and the soluble cellular content of lactobacilli have anti-inflammatory effects. We also found that pretreatment of Caco-2 cells with lactobacilli inhibited S. typhimurium-induced IL-8 production (<27.3 pg/mL). However, lactobacilli did not inhibit IL-8 production in Caco-2 cells pretreated with S. typhimurium. These results suggest that the tested lactobacilli strains are appropriate for preventing inflammatory diseases caused by enteric pathogens but not for therapy. In short, L. salivarius and L. plantarum are potential candidates for the development of microbial ecological agents and functional foods. PMID:24455739

  13. Gene conversion accounts for pilin structural changes and for reversible piliation "phase" changes in gonococci.

    PubMed

    Swanson, J; Bergstrom, S; Boslego, J; Koomey, M

    1987-01-01

    Pilus+ "wild-type" gonococci (Gc) frequently display gene conversion of their expressed complete pilin gene (CPG); a copy of DNA derived from one of the Gc genome's multiple silent partial pilin genes (PPG) is recombinationally-inserted into the CPG's central and 3' portions with formation of a new, chimeric CPG. Expression of that new CPG leads to either 1) retention of pilus+ phenotype but change in pilin primary structure/antigenicity, or 2) phase change to pilus- phenotype capable of reverting. This study utilizes pilus revertants of P-rp +/- Gc and P+ colony morphotype variants spawned by P++ Gc to examine pilin gene conversion in strain MS11mk Gc in greater detail. Each revertant's and variant's expressed pilin gene's sequence (as pilin mRNA) was defined to learn whether their differences are due to gene conversion by different PPGs, or by varying stretches from the same PPG, or both. Gene conversion by PPG pilS1 copy 2 has been documented in Gc recovered from a human volunteer's urethra previously inoculated with pilus Gc (strain MS11). The pilus+ Gc isolated expressed structurally/antigenically distinct pilins.

  14. Exogenous lactobacilli mitigate microbial changes associated with grain fermentation (corn, oats, and wheat) by equine fecal microflora ex vivo

    PubMed Central

    Harlow, Brittany E.; Lawrence, Laurie M.; Harris, Patricia A.; Aiken, Glen E.

    2017-01-01

    Cereal grains are often included in equine diets. When starch intake exceeds foregut digestion starch will reach the hindgut, impacting microbial ecology. Probiotics (e.g., lactobacilli) are reported to mitigate GI dysbioses in other species. This study was conducted to determine the effect of exogenous lactobacilli on pH and the growth of amylolytic and lactate-utilizing bacteria. Feces were collected from 3 mature geldings fed grass hay with access to pasture. Fecal microbes were harvested by differential centrifugation, washed, and re-suspended in anaerobic media containing ground corn, wheat, or oats at 1.6% (w/v) starch and one of five treatments: Control (substrate only), L. acidophilus, L. buchneri, L. reuteri, or an equal mixture of all three (107 cells/mL, final concentration). After 24 h of incubation (37°C, 160 rpm), samples were collected for pH and enumerations of total amylolytics, Group D Gram-positive cocci (GPC; Enterococci, Streptococci), lactobacilli, and lactate-utilizing bacteria. Enumeration data were log transformed prior to ANOVA (SAS, v. 9.3). Lactobacilli inhibited pH decline in corn and wheat fermentations (P < 0.0001). Specifically, addition of either L. reuteri or L. acidophilus was most effective at mitigating pH decline with both corn and wheat fermentation, in which the greatest acidification occurred (P < 0.05). Exogenous lactobacilli decreased amylolytics, while increasing lactate-utilizers in corn and wheat fermentations (P < 0.0001). In oat fermentations, L. acidophilus and L. reuteri inhibited pH decline and increased lactate-utilizers while decreasing amylolytics (P < 0.0001). For all substrates, L. reuteri additions (regardless of viability) had the lowest number of GPC and the highest number of lactobacilli and lactate-utilizers (P < 0.05). There were no additive effects when lactobacilli were mixed. Exogenous lactobacilli decreased the initial (first 8 h) rate of starch catalysis when wheat was the substrate, but did not

  15. Normal and tumour cervical cells respond differently to vaginal lactobacilli, independent of pH and lactate.

    PubMed

    Motevaseli, Elahe; Shirzad, Mahdieh; Akrami, Seyed Mohammad; Mousavi, Azam-Sadat; Mirsalehian, Akbar; Modarressi, Mohammad Hossein

    2013-07-01

    Cervical cancer is a human papilloma virus (HPV)-related cancer, but most HPV infections are transient or intermittent and resolve spontaneously. Thus, other factors, such as cervical microflora, which are dominated by lactobacilli, must be involved in invasive cervical carcinoma development after HPV infection. Previous studies have demonstrated that lactobacilli have antitumour effects, and it is possible that vaginal lactobacilli prevent cervical cancer. Here we examined the proliferative and apoptotic responses of normal and tumour cervical cells to common vaginal lactobacilli components by investigating human normal fibroblast-like cervical (normal cervical) and HeLa (cervical tumour) cell responses to Lactobacillus gasseri and Lactobacillus crispatus. The effects of different lactobacilli components, such as culture supernatants, cytoplasmic extracts, cell-wall extracts and live cells, were determined by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, trypan blue staining, lactate dehydrogenase assay and colorimetric caspase-3 activity assay. Changes in caspase-3 and human chorionic gonadotropin β (hCGβ) expression were analysed by quantitative RT-PCR. Tumour cell growth inhibition by culture supernatants was higher than that by pH- and lactate-adjusted controls. However, the effects of the supernatants on normal cells were similar to those of lactate-adjusted controls. Apoptosis was inhibited by supernatants, which was consistent with higher hCGβ expression since hCG inhibits apoptosis. Our study demonstrated that common vaginal lactobacilli exert cytotoxic effects on cervical tumour cells, but not on normal cells, and that this cytotoxicity is independent of pH and lactate. Our results encourage further studies on the interaction between lactobacilli and cervical cells, and administration of common vaginal lactobacilli as probiotics.

  16. Mechanisms and therapeutic effectiveness of lactobacilli

    PubMed Central

    Di Cerbo, Alessandro; Palmieri, Beniamino; Aponte, Maria; Morales-Medina, Julio Cesar; Iannitti, Tommaso

    2016-01-01

    The gut microbiome is not a silent ecosystem but exerts several physiological and immunological functions. For many decades, lactobacilli have been used as an effective therapy for treatment of several pathological conditions displaying an overall positive safety profile. This review summarises the mechanisms and clinical evidence supporting therapeutic efficacy of lactobacilli. We searched Pubmed/Medline using the keyword ‘Lactobacillus’. Selected papers from 1950 to 2015 were chosen on the basis of their content. Relevant clinical and experimental articles using lactobacilli as therapeutic agents have been included. Applications of lactobacilli include kidney support for renal insufficiency, pancreas health, management of metabolic imbalance, and cancer treatment and prevention. In vitro and in vivo investigations have shown that prolonged lactobacilli administration induces qualitative and quantitative modifications in the human gastrointestinal microbial ecosystem with encouraging perspectives in counteracting pathology-associated physiological and immunological changes. Few studies have highlighted the risk of translocation with subsequent sepsis and bacteraemia following probiotic administration but there is still a lack of investigations on the dose effect of these compounds. Great care is thus required in the choice of the proper Lactobacillus species, their genetic stability and the translocation risk, mainly related to inflammatory disease-induced gut mucosa enhanced permeability. Finally, we need to determine the adequate amount of bacteria to be delivered in order to achieve the best clinical efficacy decreasing the risk of side effects. PMID:26578541

  17. Estimation of vaginal probiotic lactobacilli growth parameters with the application of the Gompertz model.

    PubMed

    Juárez, TomásMaríaSilvina; de, LabandaElenaBru; de, RuizHolgadoAidaPesce; Nader-Macías, María Elena

    2002-01-01

    Lactobacilli are widely described as probiotic microorganisms used to restore the ecological balance of different animal or human tracts. For their use as probiotics, bacteria must show certain characteristics or properties related to the ability of adherence to mucosae or epithelia or show inhibition against pathogenic microorganisms. It is of primary interest to obtain the highest biomass and viability of the selected microorganisms. In this report, the growth of seven vaginal lactobacilli strains in four different growth media and at several inoculum percentages was compared, and the values of growth parameters (lag phase time, maximum growth rate, maximum optical density) were obtained by applying the Gompertz model to the experimental data. The application and estimation of this model is discussed, and the evaluation of the growth parameters is analyzed to compare the growth conditions of lactobacilli. Thus, these results in lab experiments provide a basis for testing different culture conditions to determine the best conditions in which to grow the probiotic lactobacilli for technological applications.

  18. Development of gemifloxacin in vitro susceptibility test methods for gonococci including quality control guidelines. The Quality Control Study Group.

    PubMed

    Jones, R N; Erwin, M E

    2000-07-01

    Gemifloxacin (formerly SB-265805 or LB20304a) is a new fluoronapthyridone with documented activity against Gram-positive and -negative organisms. The activity of gemifloxacin was tested against 150 Neisseria gonorrhoeae strains, using reference agar dilution, standardized disk diffusion, and Etest (AB BIODISK, Solna, Sweden) methods. Gemifloxacin was very potent against ciprofloxacin (CIPRO)-susceptible strains (MIC(90,) 0.008 microg/ml) but was significantly less active against the CIPRO-resistant gonococci (MIC(90,) 0.12 microg/ml). Etest and reference agar dilution MIC results showed excellent correlation (r = 0.96), and 98.7% MICs were within +/- one log(2) dilution. Agar dilution MICs were also compared to zone diameters obtained using gemifloxacin 5-microg disks; and complete intermethod categorical agreement (100%) was achieved applying breakpoints proposed as follows: < or =0.25 microg/ml (zone, > or =25 mm) for susceptible and > or =1 microg/ml (zone, < or =21 mm) for resistant. Gemifloxacin MIC and disk diffusion te quality control (QC) ranges were established for N. gonorrhoeae ATCC 49226. Data were collected from > or = seven laboratories, three GC agar medium lots for both agar MICs and disk methods, and two lots each of the 5- and 10-microg disks. The proposed MIC QC range was 0.002 to 0.016 microg/ml and the calculated mm zone ranges (median +/- 0.5x average mm range) for both disks were similar, but contained only 88.1 to 91.9% of participant results. To achieve the acceptable > or = 95% of all study results within range, a 43 to 54 mm limits (5-microg disks) were necessary. The excellent broad-spectrum activity and a low reported adverse effects profile of gemifloxacin shows a potential for treatment of fluoroquinolone-resistant gonorrhea.

  19. Catabolic flexibility of mammalian-associated lactobacilli

    PubMed Central

    2013-01-01

    Metabolic flexibility may be generally defined as “the capacity for the organism to adapt fuel oxidation to fuel availability”. The metabolic diversification strategies used by individual bacteria vary greatly from the use of novel or acquired enzymes to the use of plasmid-localised genes and transporters. In this review, we describe the ability of lactobacilli to utilise a variety of carbon sources from their current or new environments in order to grow and survive. The genus Lactobacillus now includes more than 150 species, many with adaptive capabilities, broad metabolic capacity and species/strain variance. They are therefore, an informative example of a cell factory capable of adapting to new niches with differing nutritional landscapes. Indeed, lactobacilli naturally colonise and grow in a wide variety of environmental niches which include the roots and foliage of plants, silage, various fermented foods and beverages, the human vagina and the mammalian gastrointestinal tract (GIT; including the mouth, stomach, small intestine and large intestine). Here we primarily describe the metabolic flexibility of some lactobacilli isolated from the mammalian gastrointestinal tract, and we also describe some of the food-associated species with a proven ability to adapt to the GIT. As examples this review concentrates on the following species - Lb. plantarum, Lb. acidophilus, Lb. ruminis, Lb. salivarius, Lb. reuteri and Lb. sakei, to highlight the diversity and inter-relationships between the catabolic nature of species within the genus. PMID:23680304

  20. Divergent signaling pathways regulate IL-12 production induced by different species of Lactobacilli in human dendritic cells.

    PubMed

    Amar, Yacine; Rizzello, Valeria; Cavaliere, Riccardo; Campana, Stefania; De Pasquale, Claudia; Barberi, Chiara; Oliveri, Daniela; Pezzino, Gaetana; Costa, Gregorio; Meddah, Aicha Tirtouil; Ferlazzo, Guido; Bonaccorsi, Irene

    2015-07-01

    Recent studies have indicated that different strains of Lactobacilli differ in their ability to regulate IL-12 production by dendritic cells (DCs), as some strains are stronger inducer of IL-12 while other are not and can even inhibit IL-12 production stimulated by IL-12-inducer Lactobacilli. In this report we demonstrate that Lactobacillus reuteri 5289, as previously described for other strains of L. reuteri, can inhibit DC production of IL-12 induced by Lactobacilllus acidophilus NCFM. Remarkably, L. reuteri 5289 was able to inhibit IL-12 production induced not only by Lactobacilli, as so far reported, but also by bacteria of different genera, including pathogens. We investigated in human DCs the signal transduction pathways involved in the inhibition of IL-12 production induced by L. reuteri 5289, showing that this potential anti-inflammatory activity, which is also accompanied by an elevated IL-10 production, is associated to a prolonged phosphorilation of ERK1/2 MAP kinase pathway. Improved understanding of the immune regulatory mechanisms exerted by Lactobacilli is crucial for a more precise employment of these commensal bacteria as probiotics in human immune-mediated pathologies, such as allergies or inflammatory bowel diseases.

  1. Prevention of Helicobacter pylori infection by lactobacilli in a gnotobiotic murine model.

    PubMed Central

    Kabir, A M; Aiba, Y; Takagi, A; Kamiya, S; Miwa, T; Koga, Y

    1997-01-01

    BACKGROUND: Helicobacter pylori is a bacterium which causes gastric inflammatory diseases. Oral inoculation of H pylori usually results in only a temporary colonisation without a successful infection in the stomach of conventional mice in which lactobacilli are the predominant indigenous bacteria. AIM: To determine whether lactobacilli exert an inhibitory effect on colonisation by H pylori in the stomach. METHODS: The effects of H pylori on attachment to murine and human gastric epithelial cells and the H pylori mediated release of interleukin-8 (IL-8) by these cells were examined in vitro. Lactobacillus salivarius infected gnotobiotic BALB/c mice and control germ free mice were inoculated orally with H pylori to examine whether L salivarius can inhibit colonisation by H pylori. RESULTS: L salivarius inhibited both the attachment and IL-8 release in vitro. H pylori could not colonise the stomach of L salivarius infected gnotobiotic BALB/c mice, but colonised in large numbers and subsequently caused active gastritis in germ free mice. In addition, L salivarius given after H pylori implantation could eliminate colonisation by H pylori. CONCLUSION: These findings suggest the possibility of lactobacilli being used as probiotic agents against H pylori. Images PMID:9274471

  2. Use of lactobacilli and their pheromone-based regulatory mechanism in gene expression and drug delivery.

    PubMed

    Diep, D B; Mathiesen, G; Eijsink, V G H; Nes, I F

    2009-01-01

    Lactobacilli are common microorganisms in diverse vegetables and meat products and several of these are also indigenous inhabitants in the gastro-intestinal (GI) tract of humans and animals where they are believed to have health promoting effects on the host. One of the highly appreciated probiotic effects is their ability to inhibit the growth of pathogens by producing antimicrobial peptides, so-called bacteriocins. Production of some bacteriocins has been shown to be strictly regulated through a quorum-sensing based mechanism mediated by a secreted peptide-pheromone (also called induction peptide; IP), a membrane-located sensor (histidine protein kinase; HPK) and a cytoplasmic response regulator (RR). The interaction between an IP and its sensor, which is highly specific, leads to activation of the cognate RR which in turn binds to regulated promoters and activates gene expression. The HPKs and RRs are built up by conserved modules, and the signalling between them within a network is efficient and directional, and can easily be activated by exogenously added synthetic IPs. Consequently, components from such regulatory networks have successfully been exploited in construction of a number of inducible gene expression systems. In this review, we discuss some well-characterised quorum sensing networks involved in bacteriocin production in lactobacilli, with special focus on the use of the regulatory components in gene expression and on lactobacilli as potential delivery vehicle for therapeutic and vaccine purposes.

  3. Cross-talk between probiotic lactobacilli and host immune system.

    PubMed

    Kemgang, T S; Kapila, S; Shanmugam, V P; Kapila, R

    2014-08-01

    The mechanism by which probiotic lactobacilli affect the immune system is strain specific. As the immune system is a multicompartmental system, each strain has its way to interact with it and induce a visible and quantifiable effect. This review summarizes the interplay existing between the host immune system and probiotic lactobacilli, that is, with emphasis on lactobacilli as a prototype probiotic genus. Several aspects including the bacterial-host cross-talk with the mucosal and systemic immune system are presented, as well as short sections on the competing effect towards pathogenic bacteria and their uses as delivery vehicle for antigens.

  4. Impact of lactobacilli on orally acquired listeriosis

    PubMed Central

    Archambaud, Cristel; Nahori, Marie-Anne; Soubigou, Guillaume; Bécavin, Christophe; Laval, Laure; Lechat, Pierre; Smokvina, Tamara; Langella, Philippe; Lecuit, Marc; Cossart, Pascale

    2012-01-01

    Listeria monocytogenes is a foodborne pathogen that crosses the intestinal barrier and disseminates within the host. Here, we report a unique comprehensive analysis of the impact of two Lactobacillus species, Lactobacillus paracasei CNCM I-3689 and Lactobacillus casei BL23, on L. monocytogenes and orally acquired listeriosis in a gnotobiotic humanized mouse model. We first assessed the effect of treatment with each Lactobacillus on L. monocytogenes counts in host tissues and showed that each decreases L. monocytogenes systemic dissemination in orally inoculated mice. A whole genome intestinal transcriptomic analysis revealed that each Lactobacillus changes expression of a specific subset of genes during infection, with IFN-stimulated genes (ISGs) being the most affected by both lactobacilli. We also examined microRNA (miR) expression and showed that three miRs (miR-192, miR-200b, and miR-215) are repressed during L. monocytogenes infection. Treatment with each Lactobacillus increased miR-192 expression, whereas only L. casei association increased miR-200b and miR-215 expression. Finally, we showed that treatment with each Lactobacillus significantly reshaped the L. monocytogenes transcriptome and up-regulated transcription of L. monocytogenes genes encoding enzymes allowing utilization of intestinal carbon and nitrogen sources in particular genes involved in propanediol and ethanolamine catabolism and cobalamin biosynthesis. Altogether, these data reveal that the modulation of L. monocytogenes infection by treatment with lactobacilli correlates with a decrease in host gene expression, in particular ISGs, miR regulation, and a dramatic reshaping of L. monocytogenes transcriptome. PMID:23012479

  5. The Role of Cell Surface Architecture of Lactobacilli in Host-Microbe Interactions in the Gastrointestinal Tract

    PubMed Central

    Altermann, Eric; Anderson, Rachel C.; McNabb, Warren C.; Moughan, Paul J.; Roy, Nicole C.

    2013-01-01

    Lactobacillus species can exert health promoting effects in the gastrointestinal tract (GIT) through many mechanisms, which include pathogen inhibition, maintenance of microbial balance, immunomodulation, and enhancement of the epithelial barrier function. Different species of the genus Lactobacillus can evoke different responses in the host, and not all strains of the same species can be considered beneficial. Strain variations may be related to diversity of the cell surface architecture of lactobacilli and the bacteria's ability to express certain surface components or secrete specific compounds in response to the host environment. Lactobacilli are known to modify their surface structures in response to stress factors such as bile and low pH, and these adaptations may help their survival in the face of harsh environmental conditions encountered in the GIT. In recent years, multiple cell surface-associated molecules have been implicated in the adherence of lactobacilli to the GIT lining, immunomodulation, and protective effects on intestinal epithelial barrier function. Identification of the relevant bacterial ligands and their host receptors is imperative for a better understanding of the mechanisms through which lactobacilli exert their beneficial effects on human health. PMID:23576850

  6. Lactobacilli Interfere with Streptococcus pyogenes Hemolytic Activity and Adherence to Host Epithelial Cells

    PubMed Central

    Saroj, Sunil D.; Maudsdotter, Lisa; Tavares, Raquel; Jonsson, Ann-Beth

    2016-01-01

    Streptococcus pyogenes [Group A streptococcus (GAS)], a frequent colonizer of the respiratory tract mucosal surface, causes a variety of human diseases, ranging from pharyngitis to the life-threatening streptococcal toxic shock-like syndrome. Lactobacilli have been demonstrated to colonize the respiratory tract. In this study, we investigated the interference of lactobacilli with the virulence phenotypes of GAS. The Lactobacillus strains L. rhamnosus Kx151A1 and L. reuteri PTA-5289, but not L. salivarius LMG9477, inhibited the hemolytic activity of S. pyogenes S165. The inhibition of hemolytic activity was attributed to a decrease in the production of streptolysin S (SLS). Conditioned medium (CM) from the growth of L. rhamnosus Kx151A1 and L. reuteri PTA-5289 was sufficient to down-regulate the expression of the sag operon, encoding SLS. The Lactobacillus strains L. rhamnosus Kx151A1, L. reuteri PTA-5289, and L. salivarius LMG9477 inhibited the initial adherence of GAS to host epithelial cells. Intriguingly, competition with a combination of Lactobacillus species reduced GAS adherence to host cells most efficiently. The data suggest that an effector molecule released from certain Lactobacillus strains attenuates the production of SLS at the transcriptional level and that combinations of Lactobacillus strains may protect the pharyngeal mucosa more efficiently from the initial colonization of GAS. The effector molecules released from Lactobacillus strains affecting the virulence phenotypes of pathogens hold potential in the development of a new generation of therapeutics. PMID:27524981

  7. Importance of lactobacilli in food and feed biotechnology.

    PubMed

    Giraffa, Giorgio; Chanishvili, Nina; Widyastuti, Yantyati

    2010-01-01

    The genus Lactobacillus is a heterogeneous group of lactic acid bacteria (LAB) with important implications in food fermentation. The ability to colonize a variety of habitats is a direct consequence of the wide metabolic versatility of this group of LAB. Consequently, lactobacilli have been used for decades in food preservation, as starters for dairy products, fermented vegetables, fish and sausages as well as silage inoculants. Lactobacilli have also been proposed as probiotics and microbial cell factories for the production of nutraceuticals. However, a wide range of applications of lactobacilli in food biotechnology remains potential, whereas a number of important strains still need to be discovered and characterized. This article provides an overview of the taxonomy of lactobacilli and describes four of the most significant case studies on the application of this group of LAB in food and feed biotechnology, including their use as probiotics, dairy starters, silage inoculants, and microbial cell factories. The importance of access to and exchange of biological material within and between different strain collections as a crucial step in expanding the range of different biotechnological applications of lactobacilli is also emphasized.

  8. Isolation and characterization of faecal bifidobacteria and lactobacilli isolated from dogs and primates.

    PubMed

    Strompfová, Viola; Lauková, Andrea

    2014-10-01

    Although bifidobacteria and lactobacilli have been suggested beneficial for the host and are components of many probiotics and competitive exclusion mixtures, the knowledge on abundance, metabolic and probiotic characteristics in isolates from dogs and monkeys is still limited. The present study was aimed to isolate Bifidobacterium and Lactobacillus strains (faeces of 22 dogs and of 5 primates: Cebus apella, Eulemur fulvus, Erythrocebus patas, Macaca fascicularis, Papio hamadryas) with the MALDI-TOF identification system Lactobacillus murinus, Bifidobacterium animalis and Pediococcus acidilactici were more frequently isolated species in dogs while Lactobacillus plantarum was isolated in several species of primates. Ten strains of 6 species were assayed for enzymatic activities (only Lactobacillus reuteri strains showed no undesirable enzymatic activity), antimicrobial susceptibility (detected higher minimum inhibitory concentration levels for tetracycline and gentamicin), and inhibitory activity against 15 indicator bacteria. All strains inhibited Gram-negative indicators while lactobacilli showed larger inhibition zones than bifidobacteria. L. reuteri II/3b/a (isolate from M. fascicularis) showed the best antimicrobial properties. Resistance to bile (0.3% w/v) was observed in all tested strains (no decrease of CFU/ml) whereas the decrease of 68.4-94.4% (after 90 min exposition) and 78.4-99.9% CFU/ml (after 180 min) depending on the strain was detected in the artificial gastric juice.

  9. Characterization of vaginal lactobacilli in women after kidney transplantation.

    PubMed

    Martirosian, G; Radosz-Komoniewska, H; Pietrzak, B; Ekiel, A; Kamiński, P; Aptekorz, M; Doleżych, H; Samulska, E; Jóźwiak, J

    2012-04-01

    Limited number of publications described vaginal microflora after kidney transplantation. Our PubMed search revealed only 18 publications including words "vaginal bacteria & kidney transplant" in the period of 1978-2011. The aim of this study was to characterize lactobacilli isolated from vaginal swabs of women after kidney transplantation, compared with healthy women. Eighteen renal transplant recipients (mean age 36.1) and 20 healthy women (mean age 36.0) were evaluated. Lactobacilli were cultured on MRS and Columbia blood agars. Biochemical identification with API 50 CHL (bioMerieux, Marcy L'Etoile, France) and multiplex PCR according to Song et al. was performed. Lactobacilli were tested for production of H(2)O(2). Minimal inhibitory concentrations (MICs) of selected antimicrobial agents were determined with E-tests (bioMerieux, Marcy L'Etoile, France) and interpreted with CLSI and EUCAST criteria. No bacterial vaginosis was found among studied women. Two strains of group I were identified as Lactobacillus delbrueckii; 18 strains as Lactobacillus gasseri and 15 strains as Lactobacillus crispatus. Only 3 strains from group II were not identified by species-specific mPCR. Group IV was represented with 2 unidentified strains. Vaginal lactobacilli isolated from healthy women represented more homogenous group compared with heterogenous renal transplant recipients. Biochemical identification of lactobacilli by API 50 CHL kits was concordant with mPCR results only in 7 cases (17.5%), all 7 strains were identified as L. crispatus. Majority (93%) of lactobacilli were H(2)O(2) producers. All isolated lactobacilli (100%) demonstrated high resistance to metronidazole (MIC > 256 μg/ml). Only 2 strains resistant to vancomycin (MICs: 32 and 256 μg/ml respectively), in the study and control group, and one to moxifloxacin (MIC = 32 μg/ml), were found. Resistance to metronidazole and vancomycin was concordant in CLSI and EUCAST (2010) criteria. Although significant

  10. Colonization by lactobacilli of piglet small intestinal mucus.

    PubMed

    Rojas, M; Conway, P L

    1996-11-01

    The colonization potential of lactobacilli was investigated using small intestinal mucus extracts from 35-d-old pigs. Mucus-secreting tissue from the small intestine of piglets was gently rinsed to remove contents and then shaken in buffer to release mucus from the surface. Numbers of lactobacilli in different portions of the small intestine of 35-d-old pigs were enumerated. Also, mucus isolated from the small intestine of pigs was investigated for its capacity to support the growth of lactobacilli. Results indicated that Lactobacillus spp. inhabit the mucus layer of the small intestine and can grow and adhere to ileal mucus. From adhesion studies of Lactobacillus fermentum 104R to mucus analysed by Scatchard plot, it is suggested that an associating system showing positive cooperativity is involved. Proteinaceous compounds(s) involved in the adhesion to mucus were detected in the spent culture fluid from the growth of strain 104R. Studies are continuing in order to identify and characterize the adhesion-promoting protein(s). From the data, it is proposed that lactobacilli colonize the mucus layer of the small intestine of pigs.

  11. Adhesive Properties and Acid-Forming Activity of Lactobacilli and Streptococci Under Inhibitory Substances, Such as Nitrates.

    PubMed

    Hakobyan, L; Harutyunyan, K; Harutyunyan, N; Melik-Andreasyan, G; Trchounian, A

    2016-06-01

    One of the main requirements for probiotics is their ability to survive during passage through gastrointestinal tract and to maintain their activity at different adverse conditions. The aim of the study was to look for the strains of lactobacilli and streptococci with high adhesive properties even affected by inhibitory substances, such as nitrates (NO3 (-)). To study the adhesion properties hemagglutination reaction of bacterial cells with red blood cells of different animals and humans was used. The acid formation ability of bacteria was determined by the method of titration after 7 days of incubation in the sterile milk. These properties were investigated at different concentrations of NO3 (-). The high concentration (mostly ≥2.0 %) NO3 (-) inhibited the growth of both lactobacilli and streptococci, but compared with streptococcal cultures lactobacilli, especially Lactobacillus acidophilus Ep 317/402, have shown more stability and higher adhesive properties. In addition, the concentrations of NO3 (-) of 0.5-2.0 % decreased the acid-forming activity of the strains, but even under these conditions they coagulated milk and, in comparison to control, formed low acidity in milk. Thus, the L. acidophilus Ep 317/402 with high adhesive properties has demonstrated a higher activity of NO3 (-) transformation.

  12. Influence of lactobacilli on the adhesion of Staphylococcus aureus and Candida albicans to fibers and epithelial cells.

    PubMed

    Reid, G; Tieszer, C; Lam, D

    1995-09-01

    The ability of organisms to adhere to and form biofilms on fibrous materials is believed to be an important initiating step in the induction of several diseases, such as toxic shock syndrome. Using an in vitro assay, a moderately hydrophobic strain of Staphylococcus aureus (water contact angle 35 degrees) and a hydrophilic Candida albicans (shown by a hexadecane test) were highly adherent to commercial diaper fibers. The lumen side of the diaper was porous and the fibers were very hydrophobic (> 140 degrees), but the internal section was very hydrophilic (0 degrees), presumably for lus strains was present. Surfaces precoated with lactobacilli inhibited staphylococcal adhesion by 26-97%, and candida by 0-67%. When the lactobacilli were used to challenge adherent pathogens, there was 99% displacement of the S. aureus and up to 91% displacement of C. albicans. Hydrophobic L. acidophilus 76 (54 degrees) and T-13 (80 degrees) were the most effective of five Lactobacillus isolates tested at interference by precoating. The moderately hydrophilic L. casei var rhamnosus GR-1 (33 degrees) was the most effective at displacing the yeast. Experiments with uroepithelial cells also showed that the lactobacilli could significantly interfere with the adhesion of both pathogens to the cells. The results demonstrate the rapidity with which two pathogens adhered to fibers and epithelial cells, and raised the possibility that members of the normal female urogenital flora might interfere with infections caused by these organisms.

  13. Acid production by oral strains of Candida albicans and lactobacilli.

    PubMed

    Klinke, T; Kneist, S; de Soet, J J; Kuhlisch, E; Mauersberger, S; Forster, A; Klimm, W

    2009-01-01

    Both Candida albicans and lactobacilli are common colonizers of carious lesions in children and adolescents. The purpose of this study is to compare the velocity of acid production between C. albicans and several Lactobacillus species at different pH levels and concentrations of glucose. Washed, pure resting-cell suspensions were obtained by culturing a total of 28 oral isolates comprising the species C. albicans, Lactobacillus rhamnosus, Lactobacillus paracasei paracasei, Lactobacillus paracasei tolerans and Lactobacillus delbrueckii lactis. Acid production from glucose was determined at a constant pH of 7.0, 5.5, 5.0 and 4.0 by repeated titrations with NaOH in an automated pH-stat system. Acid formation rates of yeast and lactobacilli proved to be similar at both neutral and low pH, while in a moderately acidic environment C. albicans produced less acid than the lactobacilli. Ion chromatographic analysis of the cell-free medium after titration revealed pyruvate to be the predominant organic acid anion secreted by C. albicans. The proportion of organic acids to overall acid production by the yeast was below 10% at neutral conditions, in contrast to 42-66% at pH 4.0. Compared to lactobacilli, yeast required a concentration of glucose that was about 50 times higher to allow acid production at half the maximum speed. Considering the clinical data in the literature about the frequency and proportions of microorganisms present in early childhood caries lesions, the contribution of oral lactobacilli as well as C. albicans to overall microbial acid formation appears to be important.

  14. Lactobacilli Differentially Modulate mTOR and Wnt/ β-Catenin Pathways in Different Cancer Cell Lines

    PubMed Central

    Taherian-Esfahani, Zahra; Abedin-Do, Atieh; Nouri, Zahra; Mirfakhraie, Reza; Ghafouri-Fard, Soudeh; Motevaseli, Elahe

    2016-01-01

    Background Lactobacilli are a group of beneficial bacteria whose anti cancer effects have been evaluated in different cancer cell lines as well as animal models and human subjects. Such anti cancer effects can be exerted via different mechanisms such as modulation of immune response as well as inhibition of pathogens colonization. In addition, lactobacilli have direct cytotoxic effects against cancer cells which may be exerted through modulation of expression cancer related pathways. Objectives The aim of this study is to find the mechanism of anti cancer effects of two lactobacilli strains, Lactobacillus. crispatus (LC) and Lactobacillus. rhamnosus (LR). Materials and Methods We analyzed expression of some mTOR and Wnt/ β-catenin pathways genes in three cancer cell lines (HeLa, MDA-MB-231 and HT-29) following treatment with LC and LR culture supernatants. Results Of note, the expression of CCND1 as a marker of cell proliferation, survival, and angiogenesis, has been decreased following LR treatment in all cell lines. In addition, the expression of SFRP2, an antagonist of Wnt pathway, has been increased in HT-29 following LR treatment and in HeLa cells following LR and LC treatments. Furthermore, we have demonstrated the downregulation of S6K1 expression, a marker of poor prognosis, following LR treatment in HT-29 and following LR and LC treatments in MDA-MB-231 cell line. Conclusions Consequently, lactobacilli can modulate expression of mTOR and Wnt/ β-catenin pathways genes in cancer cell lines in a strain specific as well as cell type specific manner. PMID:27703648

  15. Characterization and in vitro properties of oral lactobacilli in breastfed infants

    PubMed Central

    2013-01-01

    Background Lactobacillus species can contribute positively to general and oral health and are frequently acquired by breastfeeding in infancy. The present study aimed to identify oral lactobacilli in breast and formula-fed 4 month-old infants and to evaluate potential probiotic properties of the dominant Lactobacillus species detected. Saliva and oral swab samples were collected from 133 infants who were enrolled in a longitudinal study (n=240) examining the effect of a new infant formula on child growth and development. Saliva was cultured and Lactobacillus isolates were identified from 16S rRNA gene sequences. Five L. gasseri isolates that differed in 16S rRNA sequence were tested for their ability to inhibit growth of selected oral bacteria and for adhesion to oral tissues. Oral swab samples were analyzed by qPCR for Lactobacillus gasseri. Results 43 (32.3%) infants were breastfed and 90 (67.7%) were formula-fed with either a standard formula (43 out of 90) or formula supplemented with a milk fat globule membrane (MFGM) fraction (47 out of 90). Lactobacilli were cultured from saliva of 34.1% breastfed infants, but only in 4.7% of the standard and 9.3% of the MFGM supplemented formula-fed infants. L. gasseri was the most prevalent (88% of Lactobacillus positive infants) of six Lactobacillus species detected. L. gasseri isolates inhibited Streptococcus mutans binding to saliva-coated hydroxyapatite, and inhibited growth of S. mutans, Streptococcus sobrinus, Actinomyces naeslundii, Actinomyces oris, Candida albicans and Fusobacterium nucleatum in a concentration dependent fashion. L. gasseri isolates bound to parotid and submandibular saliva, salivary gp340 and MUC7, and purified MFGM, and adhered to epithelial cells. L. gasseri was detected by qPCR in 29.7% of the oral swabs. Breastfed infants had significantly higher mean DNA levels of L. gasseri (2.14 pg/uL) than infants fed the standard (0.363 pg/uL) or MFGM (0.697 pg/uL) formula. Conclusions Lactobacilli

  16. Development of Recombinant Vaccines in Lactobacilli for Elimination of Salmonella

    PubMed Central

    KAJIKAWA, Akinobu; IGIMI, Shizunobu

    2011-01-01

    Many Lactobacillus and Lactococcus strains are generally regarded as safe for consumption because they are utilized for food fermentation or inhabit the intestinal mucosa as commensals. Recently, vaccine delivery systems using lactic acid bacteria (LAB) have been under development. Our research group has been investigating the development of oral mucosal vaccines against Salmonella enterica serovar Enteritidis (SE) using Lactobacillus casei IGM393 as an antigen delivery vehicle. Recombinant lactobacilli expressing SE antigens, FliC, SipC, and OmpC, have been constructed and orally administered to mice. Antigen specific immune responses and protective immunity were elicited after the immunization. For adjuvant-delivery, IL-1β-secreting L. casei was also engineered and its effects evaluated in vitro and in vivo. This article reviews a novel approach to the elimination of Salmonella via the development of a vaccine in lactobacilli. PMID:25045314

  17. Molecular characterization of lactobacilli isolated from fermented idli batter

    PubMed Central

    Agaliya, Perumal Jayaprabha; Jeevaratnam, Kadirvelu

    2013-01-01

    Lactic acid bacteria are non pathogenic organism widely distributed in nature typically involved in a large number of spontaneous food fermentation. The purpose of this study was to characterize the bacteriocinogenic lactobacilli from fermented idli batter which can find application in biopreservation and biomedicine. Eight most promising lactobacilli were chosen from twenty two isolates based on their spectrum of activity against other lactic acid bacteria and pathogens. The eight lactobacilli were characterized based on the various classical phenotypic tests, physiological tests and biochemical tests including various carbohydrate utilization profiles. All isolates were homo fermentative, catalase, and gelatin negative. Molecular characterization was performed by RAPD, 16S rRNA analysis, 16S ARDRA, and Multiplex PCR for species identification. RAPD was carried out using the primer R2 and M13. Five different clusters were obtained based on RAPD indicating strain level variation. 16S rRNA analysis showed 99 to 100% homology towards Lactobacillus plantarum. The restriction digestion pattern was similar for all the isolates with the restriction enzyme AluI. The subspecies were identified by performing Multiplex PCR using species specific primer. Among the five clusters, three clusters were clearly identified as Lactobacillus plantarum subsp. plantarum, Lactobacillus pentosus, and Lactobacillus plantarum subsp. argentoratensis. PMID:24688512

  18. Enhanced growth of lactobacilli in soymilk upon immobilization on agrowastes.

    PubMed

    Teh, Sue-Siang; Ahmad, Rosma; Wan-Abdullah, Wan-Nadiah; Liong, Min-Tze

    2010-04-01

    Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. The objective of this study was to evaluate the effects of agrowastes from durian (Durio zibethinus), cempedak (Artocarpus champeden), and mangosteen (Garcinia mangostana) as immobilizers for lactobacilli grown in soymilk. Rinds from the agrowastes were separated from the skin, dried, and ground (150 microm) to form powders and used as immobilizers. Scanning electron microscopy revealed that lactobacilli cells were attached and bound to the surface of the immobilizers. Immobilized cells of Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and L. bulgaricus FTCC 0411 were inoculated into soymilk, stored at room temperature (25 degrees C) and growth properties were evaluated over 168 h. Soymilk inoculated with nonimmobilized cells was used as the control. Utilization of substrates, concentrations of lactic and acetic acids, and changes in pH were evaluated in soymilk over 186 h. Immobilized lactobacilli showed significantly better growth (P < 0.05) compared to the control, accompanied by higher production of lactic and acetic acids in soymilk. Soymilk containing immobilized cells showed greater reduction of soy sugars such as stachyose, raffinose, sucrose, fructose, and glucose compared to the control (P < 0.05).

  19. Molecular characterization of lactobacilli isolated from fermented idli batter.

    PubMed

    Agaliya, Perumal Jayaprabha; Jeevaratnam, Kadirvelu

    2013-12-01

    Lactic acid bacteria are non pathogenic organism widely distributed in nature typically involved in a large number of spontaneous food fermentation. The purpose of this study was to characterize the bacteriocinogenic lactobacilli from fermented idli batter which can find application in biopreservation and biomedicine. Eight most promising lactobacilli were chosen from twenty two isolates based on their spectrum of activity against other lactic acid bacteria and pathogens. The eight lactobacilli were characterized based on the various classical phenotypic tests, physiological tests and biochemical tests including various carbohydrate utilization profiles. All isolates were homo fermentative, catalase, and gelatin negative. Molecular characterization was performed by RAPD, 16S rRNA analysis, 16S ARDRA, and Multiplex PCR for species identification. RAPD was carried out using the primer R2 and M13. Five different clusters were obtained based on RAPD indicating strain level variation. 16S rRNA analysis showed 99 to 100% homology towards Lactobacillus plantarum. The restriction digestion pattern was similar for all the isolates with the restriction enzyme AluI. The subspecies were identified by performing Multiplex PCR using species specific primer. Among the five clusters, three clusters were clearly identified as Lactobacillus plantarum subsp. plantarum, Lactobacillus pentosus, and Lactobacillus plantarum subsp. argentoratensis.

  20. A Genomic View of Lactobacilli and Pediococci Demonstrates that Phylogeny Matches Ecology and Physiology.

    PubMed

    Zheng, Jinshui; Ruan, Lifang; Sun, Ming; Gänzle, Michael

    2015-10-01

    Lactobacilli are used widely in food, feed, and health applications. The taxonomy of the genus Lactobacillus, however, is confounded by the apparent lack of physiological markers for phylogenetic groups of lactobacilli and the unclear relationships between the diverse phylogenetic groups. This study used the core and pan-genomes of 174 type strains of Lactobacillus and Pediococcus to establish phylogenetic relationships and to identify metabolic properties differentiating phylogenetic groups. The core genome phylogenetic tree separated homofermentative lactobacilli and pediococci from heterofermentative lactobacilli. Aldolase and phosphofructokinase were generally present in homofermentative but not in heterofermentative lactobacilli; a two-domain alcohol dehydrogenase and mannitol dehydrogenase were present in most heterofermentative lactobacilli but absent in most homofermentative organisms. Other genes were predominantly present in homofermentative lactobacilli (pyruvate formate lyase) or heterofermentative lactobacilli (lactaldehyde dehydrogenase and glycerol dehydratase). Cluster analysis of the phylogenomic tree and the average nucleotide identity grouped the genus Lactobacillus sensu lato into 24 phylogenetic groups, including pediococci, with stable intra- and intergroup relationships. Individual groups may be differentiated by characteristic metabolic properties. The link between phylogeny and physiology that is proposed in this study facilitates future studies on the ecology, physiology, and industrial applications of lactobacilli.

  1. Properties of porcine and yogurt lactobacilli in relation to lactose intolerance.

    PubMed

    Burton, J P; Tannock, G W

    1997-10-01

    Lactobacilli that had been isolated from the stomach of piglets were tested for properties relevant to the production of fermented milk products for consumption by lactose-intolerant humans. The strains were characterized for beta-galactosidase activity, the ability to reduce the lactose concentration of milk, viability, and pH of the fermented milk over a 30-d period. Strains that had favorable attributes were studied further, and the optimal pH for beta-galactosidase activity, ability to grow in the presence of bile salts, and ability to deconjugate bile salts were determined. Commercial yogurts were also examined to determine whether products varied in characteristics that might affect tolerance of milk products by lactose-intolerant subjects. The Lactobacillus sp. isolated from pigs had lower beta-galactosidase activity than did Lactobacillus delbrueckii ssp. bulgaricus strains ATCC 11842 and NCDO 1489 and strains of lactobacilli isolated from yogurt. The beta-galactosidase activity of all strains decreased rapidly once the fermented milk was stored at 4 degrees C. Strain JB10, originating in the stomach contents of the piglets, had properties that were useful for the manufacture of fermented milk products for lactose-intolerant humans. Milk fermented by this strain had a lactose concentration of about 4.0% and contained 6.6 x 10(6) cfu/ml after storage at 4 degrees C for 20 d. Strain JB10 produced a beta-galactosidase that was active at pH 5.5 (35% of the activity at pH 7.0) and was not inhibited by the presence of bile acids in the culture medium. Beta-Galactosidase activity and lactose concentration varied among yogurts.

  2. Lactobacilli and dairy propionibacterium with potential as biopreservatives against food fungi and yeast contamination.

    PubMed

    Ho, P H; Luo, J B; Adams, M C

    2009-01-01

    Naturally fermented and raw foods contain a range of organisms that may have benefit as additives in some foods and food processing. In particular, potential anti-fungal properties of these organisms may be potentially utilised as natural alternatives to chemical additives used to delay and prevent spoilage by fungi and yeast. This study examined 12 novel bacteria previously isolated from food as possible biopreservatives. The bacteria from the lactobacilli and dairy propionibacterium groups were tested by agar overlay method for their ability to inhibit the growth of 10 fungi and one yeast commonly associated with food contamination. Eight among eleven tested lactic acid bacteria demonstrated broad spectrum of antifungal activity. Strong fungi inhibition was also demonstrated by the dairy propionibacterium, but efficacy was growth medium dependant. Only one fungi, Geotrichum candidum was highly resistant to the bacteria. Variation between the inhibition results for different bacteria identifies the importance of careful strain selection, and the benefits of strain combinations when selecting biopreservatives for foods.

  3. β-Glucuronidase and β-glucosidase activity and human fecal water genotoxicity in the presence of probiotic lactobacilli and the heterocyclic aromatic amine IQ in vitro.

    PubMed

    Nowak, Adriana; Śliżewska, Katarzyna

    2014-01-01

    The aim of the study was to assess the genotoxicity of fecal water (FW) and the activity of fecal enzymes (β-glucuronidase and β-glucosidase) after incubation with 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) and probiotic lactobacilli: Lb. casei 0900, Lb. casei 0908, and Lb. paracasei 0919. Our results show that the carcinogen IQ greatly increased FW genotoxicity (up to 16.92 ± 3.03 U/mg) and the activity of fecal enzymes (up to even 1.4 ± 0.16 U/mg) in 15 individuals (children, adults and elderly). After incubation with IQ, the activity of β-glucuronidase was reduced by Lactobacillus bacteria by 76.0% (Lb. paracasei 0908) in the FW of children, and by 82.0% (Lb. paracasei 0919) in the elderly; while that of β-glucosidase was reduced by 55.0% in children (Lb. casei 0908) and 90.0% (Lb. paracasei 0919) in elderly subjects. Lactobacilli decreased the genotoxicity of FW after incubation with IQ to the greatest extent in adults (by 64.5%). Probiotic lactobacilli, in the presence of IQ, efficiently inhibits activity of fecal enzymes to the level of control. Genotoxicity inhibition depends on the person's age, its individual microbiota and diet.

  4. Characterisation of probiotic properties in human vaginal lactobacilli strains

    PubMed Central

    Hütt, Pirje; Lapp, Eleri; Štšepetova, Jelena; Smidt, Imbi; Taelma, Heleri; Borovkova, Natalja; Oopkaup, Helen; Ahelik, Ave; Rööp, Tiiu; Hoidmets, Dagmar; Samuel, Külli; Salumets, Andres; Mändar, Reet

    2016-01-01

    Background Vaginal lactobacilli offer protection against recurrent urinary infections, bacterial vaginosis, and vaginal candidiasis. Objective To characterise the isolated vaginal lactobacilli strains for their probiotic properties and to compare their probiotic potential. Methods The Lactobacillus strains were isolated from vaginal samples by conventional culturing and identified by sequencing of the 16S rDNA fragment. Several functional properties were detected (production of hydrogen peroxide and lactic acid; antagonistic activity against Escherichia coli, Candida albicans, Candida glabrata, and Gardnerella vaginalis; auto-aggregation and adhesiveness) as well as safety (haemolytic activity, antibiotic susceptibility, presence of transferrable resistance genes). Results A total of 135 vaginal lactobacilli strains of three species, Lactobacillus crispatus (56%), Lactobacillus jensenii (26%), and Lactobacillus gasseri (18%) were characterised using several functional and safety tests. Most of L. crispatus (89%) and L. jensenii (86%) strains produced H2O2. The best lactic acid producers were L. gasseri (18.2±2.2 mg/ml) compared to L. crispatus (15.6±2.8 mg/ml) and L. jensenii (11.6±2.6 mg/ml) (p<0.0001; p<0.0001, respectively). L. crispatus strains showed significantly higher anti-E. coli activity compared to L. jensenii. L. gasseri strains expressed significantly lower anticandidal activity compared to L. crispatus and L. jensenii (p<0.0001). There was no significant difference between the species in antagonistic activity against G. vaginalis. Nearly a third of the strains were able to auto-aggregate while all the tested strains showed a good ability to adhere to HeLa cells. None of the tested lactobacilli caused haemolysis. Although phenotypical resistance was not found to ampicillin, chloramphenicol, erythromycin, gentamycin, tetracycline, and vancomycin, the erm(B), tet(M), and tet(K) were detected in some strains. All strains were resistant to metronidazole

  5. Glycerol Monolaurate Does Not Alter Rhesus Macaque (Macaca mulatta) Vaginal Lactobacilli and Is Safe for Chronic Use▿

    PubMed Central

    Schlievert, Patrick M.; Strandberg, Kristi L.; Brosnahan, Amanda J.; Peterson, Marnie L.; Pambuccian, Stefan E.; Nephew, Karla R.; Brunner, Kevin G.; Schultz-Darken, Nancy J.; Haase, Ashley T.

    2008-01-01

    Glycerol monolaurate (GML) is a fatty acid monoester that inhibits growth and exotoxin production of vaginal pathogens and cytokine production by vaginal epithelial cells. Because of these activities, and because of the importance of cytokine-mediated immune activation in human immunodeficiency virus type 1 (HIV-1) transmission to women, our laboratories are performing studies on the potential efficacy of GML as a topical microbicide to interfere with HIV-1 transmission in the simian immunodeficiency virus-rhesus macaque model. While GML is generally recognized as safe by the FDA for topical use, its safety for chronic use and effects on normal vaginal microflora in this animal model have not been evaluated. GML was therefore tested both in vitro for its effects on vaginal flora lactobacilli and in vivo as a 5% gel administered vaginally to monkeys. In vitro studies demonstrated that lactobacilli are not killed by GML; GML blocks the loss of their viability in stationary phase and does not interfere with lactic acid production. GML (5% gel) does not quantitatively alter monkey aerobic vaginal microflora compared to vehicle control gel. Lactobacilli and coagulase-negative staphylococci are the dominant vaginal aerobic microflora, with beta-hemolytic streptococci, Staphylococcus aureus, and yeasts sporadically present; gram-negative rods are not part of their vaginal flora. Colposcopy and biopsy studies indicate that GML does not alter normal mucosal integrity and does not induce inflammation; instead, GML reduces epithelial cell production of interleukin 8. The studies suggest that GML is safe for chronic use in monkeys when applied vaginally; it does not alter either mucosal microflora or integrity. PMID:18838587

  6. Glycerol monolaurate does not alter rhesus macaque (Macaca mulatta) vaginal lactobacilli and is safe for chronic use.

    PubMed

    Schlievert, Patrick M; Strandberg, Kristi L; Brosnahan, Amanda J; Peterson, Marnie L; Pambuccian, Stefan E; Nephew, Karla R; Brunner, Kevin G; Schultz-Darken, Nancy J; Haase, Ashley T

    2008-12-01

    Glycerol monolaurate (GML) is a fatty acid monoester that inhibits growth and exotoxin production of vaginal pathogens and cytokine production by vaginal epithelial cells. Because of these activities, and because of the importance of cytokine-mediated immune activation in human immunodeficiency virus type 1 (HIV-1) transmission to women, our laboratories are performing studies on the potential efficacy of GML as a topical microbicide to interfere with HIV-1 transmission in the simian immunodeficiency virus-rhesus macaque model. While GML is generally recognized as safe by the FDA for topical use, its safety for chronic use and effects on normal vaginal microflora in this animal model have not been evaluated. GML was therefore tested both in vitro for its effects on vaginal flora lactobacilli and in vivo as a 5% gel administered vaginally to monkeys. In vitro studies demonstrated that lactobacilli are not killed by GML; GML blocks the loss of their viability in stationary phase and does not interfere with lactic acid production. GML (5% gel) does not quantitatively alter monkey aerobic vaginal microflora compared to vehicle control gel. Lactobacilli and coagulase-negative staphylococci are the dominant vaginal aerobic microflora, with beta-hemolytic streptococci, Staphylococcus aureus, and yeasts sporadically present; gram-negative rods are not part of their vaginal flora. Colposcopy and biopsy studies indicate that GML does not alter normal mucosal integrity and does not induce inflammation; instead, GML reduces epithelial cell production of interleukin 8. The studies suggest that GML is safe for chronic use in monkeys when applied vaginally; it does not alter either mucosal microflora or integrity.

  7. Reduction of Campylobacter jejuni in a simulated chicken digestive tract by Lactobacilli cultures.

    PubMed

    Chang, M H; Chen, T C

    2000-11-01

    Studies were conducted to investigate the impact of a selected lactobacilli mixed culture on Campylobacter jejuni in simulated chicken digestive tract models. Veronal buffer solutions corresponding to the pH of successive segments of the chicken digestive tract were prepared. The lactobacilli mixtures were prepared by mixing four fresh lactobacilli cultures, including Lactobacillus acidophilus, Lactobacillus fermenentum, Lactobacillus crispatus, and Lactobacillus brevis. The C. jejuni and lactobacilli mixture were mixed with sterile poultry feed, and the previously prepared veronal buffer solutions were then added separately. The mixture was incubated at 41.1 degrees C for various lengths of time with periodic agitation. The feed passage time for five segments of the digestive tract were adopted: crop (pH 4.5), 30 min; proventriculus (pH 4.4), 15 min; gizzard (pH 2.6), 90 min; small intestine (pH 6.2), 90 min; and large intestine (pH 6.3), 15 min. The Campylobacter and lactobacilli were enumerated. An antagonistic effect on C. jejuni by the tested lactobacilli spp. was found in individual sections and the complete simulated digestive tract models. In the simulated complete chicken digestion system, no C. jejuni were found during the final incubation period when a lactobacilli mixture was present. The results of this in vitro study indicate the potential value of future in vivo studies.

  8. Impact of chymosin- and plasmin-mediated primary proteolysis on the growth and biochemical activities of lactobacilli in miniature Cheddar-type cheeses.

    PubMed

    Milesi, M M; McSweeney, P L H; Hynes, E R

    2008-09-01

    Strongly proteolytic starters seem to improve the growth of nonstarter lactobacilli during cheese ripening, but no information is available on the impact of the nonmicrobial proteases usually active in cheese on their development. In the current study, the influence of chymosin- and plasmin-mediated proteolysis on the growth and biochemical activities of lactobacilli during ripening of miniature Cheddar-type cheeses, manufactured under controlled microbiological conditions, was studied. Two experiments were performed; in the first, residual chymosin activity was inhibited by the addition of pepstatin, and in the second, plasmin activity was increased by adding more enzyme, obtained in vitro through the activation of plasminogen induced by urokinase. Cheeses with or without a Lactobacillus plantarum I91 adjunct culture and with or without added pepstatin or plasmin solution were manufactured and ripened for 60 d. The addition of the adjunct culture resulted in enhancement of secondary proteolysis, evidenced by an increase in the total content of free amino acids (FAA) and modifications of the individual FAA profiles. Reduction in residual chymosin activity caused a decrease in primary and secondary proteolysis, characterized by the absence of alpha(s1)-casein hydrolysis and reduced production of peptides and FAA, respectively. The increase in plasmin activity accelerated primary proteolysis but no enhancement of secondary proteolysis was observed. Chymosin- and plasmin-mediated proteolysis did not influence the growth and biochemical activities of adventitious or adjunct lactobacilli, indicating that it is not a limiting factor for the development and proteolytic-peptidolytic activities of lactobacilli in the cheese model studied.

  9. Determining the Genetic Diversity of Lactobacilli from the Oral Cavity

    PubMed Central

    Yang, R.; Argimon, S.; Li, Y.; Zhou, X.; Caufield, P. W.

    2010-01-01

    Summary Several methods for determining the diversity of Lactobacillus spp were evaluated with the purpose of developing a realistic approach for further studies. The patient population was comprised of young children with an oral disease called severe early childhood caries. The ultimate goal of these studies was to ascertain the role of lactobacilli in the caries process. To accomplish that goal, we evaluated several methods and approaches for determining diversity including AP-PCR, chromosomal DNA fingerprinting, denaturing gradient gel electrophoresis, and 16S rRNA gene sequencing. Central to these methods was the gathering and screening of isolates from cultivation medium. Using various estimates of diversity, we addressed the question as to how many isolates represent the overall diversity and how cultivation compares to non-cultivation techniques. Finally, we proposed a working approach for achieving the goals outlined framed by both practical constraints in terms of time, effort and efficacy while yielding a reliable outcome. PMID:20573585

  10. Expanding the biotechnology potential of lactobacilli through comparative genomics of 213 strains and associated genera.

    PubMed

    Sun, Zhihong; Harris, Hugh M B; McCann, Angela; Guo, Chenyi; Argimón, Silvia; Zhang, Wenyi; Yang, Xianwei; Jeffery, Ian B; Cooney, Jakki C; Kagawa, Todd F; Liu, Wenjun; Song, Yuqin; Salvetti, Elisa; Wrobel, Agnieszka; Rasinkangas, Pia; Parkhill, Julian; Rea, Mary C; O'Sullivan, Orla; Ritari, Jarmo; Douillard, François P; Paul Ross, R; Yang, Ruifu; Briner, Alexandra E; Felis, Giovanna E; de Vos, Willem M; Barrangou, Rodolphe; Klaenhammer, Todd R; Caufield, Page W; Cui, Yujun; Zhang, Heping; O'Toole, Paul W

    2015-09-29

    Lactobacilli are a diverse group of species that occupy diverse nutrient-rich niches associated with humans, animals, plants and food. They are used widely in biotechnology and food preservation, and are being explored as therapeutics. Exploiting lactobacilli has been complicated by metabolic diversity, unclear species identity and uncertain relationships between them and other commercially important lactic acid bacteria. The capacity for biotransformations catalysed by lactobacilli is an untapped biotechnology resource. Here we report the genome sequences of 213 Lactobacillus strains and associated genera, and their encoded genetic catalogue for modifying carbohydrates and proteins. In addition, we describe broad and diverse presence of novel CRISPR-Cas immune systems in lactobacilli that may be exploited for genome editing. We rationalize the phylogenomic distribution of host interaction factors and bacteriocins that affect their natural and industrial environments, and mechanisms to withstand stress during technological processes. We present a robust phylogenomic framework of existing species and for classifying new species.

  11. Expanding the biotechnology potential of lactobacilli through comparative genomics of 213 strains and associated genera

    PubMed Central

    Sun, Zhihong; Harris, Hugh M. B.; McCann, Angela; Guo, Chenyi; Argimón, Silvia; Zhang, Wenyi; Yang, Xianwei; Jeffery, Ian B; Cooney, Jakki C.; Kagawa, Todd F.; Liu, Wenjun; Song, Yuqin; Salvetti, Elisa; Wrobel, Agnieszka; Rasinkangas, Pia; Parkhill, Julian; Rea, Mary C.; O'Sullivan, Orla; Ritari, Jarmo; Douillard, François P.; Paul Ross, R.; Yang, Ruifu; Briner, Alexandra E.; Felis, Giovanna E.; de Vos, Willem M.; Barrangou, Rodolphe; Klaenhammer, Todd R.; Caufield, Page W.; Cui, Yujun; Zhang, Heping; O'Toole, Paul W.

    2015-01-01

    Lactobacilli are a diverse group of species that occupy diverse nutrient-rich niches associated with humans, animals, plants and food. They are used widely in biotechnology and food preservation, and are being explored as therapeutics. Exploiting lactobacilli has been complicated by metabolic diversity, unclear species identity and uncertain relationships between them and other commercially important lactic acid bacteria. The capacity for biotransformations catalysed by lactobacilli is an untapped biotechnology resource. Here we report the genome sequences of 213 Lactobacillus strains and associated genera, and their encoded genetic catalogue for modifying carbohydrates and proteins. In addition, we describe broad and diverse presence of novel CRISPR-Cas immune systems in lactobacilli that may be exploited for genome editing. We rationalize the phylogenomic distribution of host interaction factors and bacteriocins that affect their natural and industrial environments, and mechanisms to withstand stress during technological processes. We present a robust phylogenomic framework of existing species and for classifying new species. PMID:26415554

  12. In vitro inhibition of growth of Neisseria gonorrhoeae by Neisseria meningitidis isolated from the pharynx of homosexual men.

    PubMed

    Bisaillon, J G; Turgeon, P; Dubreuil, D; Beaudet, R; Sylvestre, M; Ashton, F E

    1984-01-01

    Despite the high prevalence of pharyngeal gonorrhea and of meningococcal carriage among homosexual men, Neisseria gonorrhoeae and Neisseria meningitidis are rarely co-isolated from the throat. Forty-seven meningococcal isolates from the pharynx of homosexual men were examined, by a lawn-spotting method, for their ability to inhibit N. gonorrhoeae in vitro. Eight (17%) of the meningococcal isolates were inhibitory when tested against gonococci from the same patient, while 31 (66%) were inhibitory when tested against N. gonorrhoeae strain 650 (T1). The colonial type T1 of a given strain was, in all cases tested, more sensitive to the inhibitory activities than the corresponding T4 type. Since the meningococci co-isolated from the throat with gonococci were at least as inhibitory in vitro as those isolated without gonococci, the natural resistance to gonococcal pharyngitis cannot be explained on the basis of the inhibitory activities produced by the meningococci in vitro. The inhibitory strains of N. meningitidis were identified in decreasing importance as: nonserogroupable, W135, C, B, 29E, and X. The addition of trypsin to the solid medium removed the inhibition produced by the meningococci, an observation suggesting the involvement of protein inhibitors.

  13. Effects of lactobacilli on yeast-catalyzed ethanol fermentations.

    PubMed Central

    Narendranath, N V; Hynes, S H; Thomas, K C; Ingledew, W M

    1997-01-01

    Normal-gravity (22 to 24 degrees Plato) wheat mashes were inoculated with five industrially important strains of lactobacilli at approximately 10(5), approximately 10(6), approximately 10(7), approximately 10(8), and approximately 10(9) CFU/ml in order to study the effects of the lactobacilli on yeast growth and ethanol productivity. Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus #3, Lactobacillus rhamnosus, and Lactobacillus fermentum were used. Controls with yeast cells but no bacterial inoculation and additional treatments with bacteria alone inoculated at approximately 10(7) CFU/ml of mash were included. Decreased ethanol yields were due to the diversion of carbohydrates for bacterial growth and the production of lactic acid. As higher numbers of the bacteria were produced (depending on the strain), 1 to 1.5% (wt/vol) lactic acid resulted in the case of homofermentative organisms. L. fermentum, a heterofermentative organism, produced only 0.5% (wt/vol) lactic acid. When L. plantarum, L. rhamnosus, and L. fermentum were inoculated at approximately 10(6) CFU/ml, an approximately 2% decrease in the final ethanol concentration was observed. Smaller initial numbers (only 10(5) CFU/ml) of L. paracasei or Lactobacillus #3 were sufficient to cause more than 2% decreases in the final ethanol concentrations measured compared to the control. Such effects after an inoculation of only 10(5) CFU/ml may have been due to the higher tolerance to ethanol of the latter two bacteria, to the more rapid adaptation (shorter lag phase) of these two industrial organisms to fermentation conditions, and/or to their more rapid growth and metabolism. When up to 10(9) CFU of bacteria/ml was present in mash, approximately 3.8 to 7.6% reductions in ethanol concentration occurred depending on the strain. Production of lactic acid and a suspected competition with yeast cells for essential growth factors in the fermenting medium were the major reasons for reductions in yeast

  14. Lack of correlation between in vitro antibiosis and in vivo protection against enteropathogenic bacteria by probiotic lactobacilli.

    PubMed

    Bujalance, Carmen; Jiménez-Valera, María; Moreno, Encarnación; Ruiz-López, María-Dolores; Lasserrot, Agustín; Ruiz-Bravo, Alfonso

    2014-01-01

    Increased resistance to infection is one of the beneficial effects attributed to probiotic microorganisms. This effect may be due to several mechanisms: production of inhibitory substances, blocking of adhesion sites on the intestinal surface, competition for nutrients and stimulation of mucosal and systemic immunity. The present study aimed to investigate the correlation between in vitro and in vivo antimicrobial activity of probiotic lactobacilli. The agar spot test was used to show that twenty Lactobacillus strains were able to inhibit the enteropathogenic bacterium Yersinia enterocolitica. This inhibition was mainly attributable to a decrease in pH resulting from dextrose fermentation by lactobacilli. The inhibition of Y. enterocolitica, Salmonella enterica serovar Typhimurium and Listeria monocytogenes by two probiotic strains, Lactobacillus casei C1 and Lactobacillus plantarum C4, was also associated with the pH decrease. However, both strains lacked protective effects in mouse experimental infection models, with the exception of long-lasting pre-treatment with L. plantarum C4, which exerted a partial protective effect against S. Typhimurium that was attributable to an immunostimulatory mechanism. Our results show that in vitro antibiosis tests do not provide useful information on the probiotic potential of Lactobacillus strains.

  15. Sugar-glycerol cofermentations in lactobacilli: the fate of lactate.

    PubMed

    Veiga da Cunha, M; Foster, M A

    1992-02-01

    The simultaneous fermentation of glycerol and sugar by lactobacillus brevis B22 and Lactobacillus buchneri B190 increases both the growth rate and total growth. The reduction of glycerol to 1,3-propanediol by the lactobacilli was found to influence the metabolism of the sugar cofermented by channelling some of the intermediate metabolites (e.g., pyruvate) towards NADH-producing (rather than NADH-consuming) reactions. Ultimately, the absolute requirement for NADH to prevent the accumulation of 3-hydroxypropionaldehyde leads to a novel lactate-glycerol cofermentation. As a result, additional ATP can be made not only by (i) converting pyruvate to acetate via acetyl phosphate rather than to the ethanol usually found and (ii) oxidizing part of the intermediate pyruvate to acetate instead of the usual reduction to lactate but also by (iii) reoxidation of accumulated lactate to acetate via pyruvate. The conversion of lactate to pyruvate is probably catalyzed by NAD-independent lactate dehydrogenases that are found only in the cultures oxidizing lactate and producing 1,3-propanediol, suggesting a correlation between the expression of these enzymes and a raised intracellular NAD/NADH ratio. The enzymes metabolizing glycerol (glycerol dehydratase and 1,3-propanediol dehydrogenase) were expressed in concert without necessary induction by added glycerol, although their expression may also be influenced by the intracellular NAD/NADH ratio set by the different carbohydrates fermented.

  16. Carbohydrate catabolic diversity of bifidobacteria and lactobacilli of human origin.

    PubMed

    McLaughlin, Heather P; Motherway, Mary O'Connell; Lakshminarayanan, Bhuvaneswari; Stanton, Catherine; Paul Ross, R; Brulc, Jennifer; Menon, Ravi; O'Toole, Paul W; van Sinderen, Douwe

    2015-06-16

    Because increased proportions of particular commensal bacteria such as bifidobacteria and lactobacilli have been linked to human health through a variety of mechanisms, there is corresponding interest in identifying carbohydrates that promote growth and metabolic activity of these bacteria. We evaluated the ability of 20 carbohydrates, including several commercially available carbohydrates that are sold as prebiotic ingredients, to support growth of 32 human-derived isolates belonging to the genera Bifidobacterium and Lactobacillus, including those isolated from healthy elderly subjects. In general, bifidobacterial strains were shown to display more diverse carbohydrate utilization profiles compared to the tested Lactobacillus species, with several bifidobacterial strains capable of metabolizing xylo-oligosaccharide (XOS), arabinoxylan, maltodextrin, galactan and carbohydrates containing fructo-oligosaccharide (FOS) components. In contrast, maltodextrin, galactan, arabinogalactan and galactomannan did not support robust growth (≥0.8 OD600 nm) of any of the Lactobacillus strains assessed. Carbohydrate fermentation was variable among strains tested of the same species for both genera. This study advances our knowledge of polysaccharide utilization by human gut commensals, and provides information for the rational design of selective prebiotic food ingredients.

  17. Impact of oral Lactobacillus acidophilus gavage on rooster seminal and cloacal Lactobacilli concentrations.

    PubMed

    Kiess, A S; Hirai, J H; Triplett, M D; Parker, H M; McDaniel, C D

    2016-08-01

    The use of antibiotics in poultry is being heavily scrutinized, therefore alternatives such as probiotics are being investigated. Lactobacilli spp. are a commonly used bacteria in formulating probiotics, and the addition of Lactobacilli to broiler diets has demonstrated increased growth rates, stimulated immune systems, and reduced pathogen loads in the gastro-intestinal tract ( GI: ) tract. However, previous research has shown that when rooster semen is directly exposed to Lactobacillus acidophilus (L. acidophilus) sperm quality is reduced. Therefore, the objective of the current study was to determine if oral administration of L. acidophilus increases the concentration of Lactobacilli in semen as well as the cloaca. A total of 30 roosters were used: 15 roosters were gavaged with 1X PBS (Control) and 15 roosters were gavaged with 10(7) cfu/mL of L. acidophilus (Treated). All roosters were gavaged for 14 consecutive days. Semen was collected on a 3 d interval, and cloacal swabs were collected on a 2 d interval, beginning on the first day prior to oral administration. Semen and cloacal swabs were serial diluted, and 100 μL of each dilution was then plated on Man, Rogosa, Sharpe ( MRS: ) agar plates. All plates were incubated for 48 h at 37°C under anaerobic conditions and counted. All Lactobacilli counts were first log transformed, then log transformed (day 0) pre-counts were subtracted from the log transformed day counts providing log differences for the analysis. Seminal Lactobacilli counts were not altered by treatments. However, the main effect of treatment (P = 0.026) for cloacal counts indicated that roosters gavaged with Lactobacilli yielded higher counts than the controls. Additionally, cloaca samples also demonstrated a treatment by day interaction trend (P = 0.082), where Lactobacilli was higher in the L. acidophilus gavaged roosters than the controls only on days 3, 5, 13, and 15. In conclusion, the addition of L. acidophilus to the male breeder diet

  18. Acid and bile tolerance and cholesterol removal ability of lactobacilli strains.

    PubMed

    Liong, M T; Shah, N P

    2005-01-01

    Eleven strains of lactobacilli were studied for their acid and bile tolerance. Possible mechanisms of cholesterol removal by strains of lactobacilli were examined. Cholesterol assimilation as determined by the difference in cholesterol content in the medium before and after the incubation period showed that all lactobacilli strains were able to assimilate cholesterol at varying levels ranging from 12.03 to 32.25 microg/mL. Cholesterol removal was associated with growth of cultures. Binding of cholesterol to lactobacilli cells was determined using growing, heat-killed, and resting cells in phosphate buffer. Cholesterol removed by dead and resting cells ranged from 0.79 to 3.82 mg/g of dry weight compared with growing cells, which ranged from 4.53 to 16.03 mg/g of dry weight. Fatty acid methyl esters, as quantified using gas chromatography, showed changes in lipid profiles in cells grown in the presence of cholesterol compared with those grown without cholesterol. Fatty acid profiles, especially of hexadecanoic, octadecanoic, total saturated, and unsaturated acids suggested that cholesterol from the medium was incorporated into the cellular membrane. These findings suggest that strains of lactobacilli could remove cholesterol via various mechanisms and may be promising candidates for use as a dietary adjunct to lower serum cholesterol in vivo.

  19. Ecology of Lactobacilli in the Oral Cavity: A Review of Literature

    PubMed Central

    Badet, C; Thebaud, N.B

    2008-01-01

    Lactobacilli appear in the oral cavity during the first years of a child’s life. Their presence depends on numerous factors such as the presence of ecological niches e.g. natural anfractuosities of the teeth. A strong correlation has been established between the saliva Lactobacillus count and dental caries, the higher the DMF index, the higher the number of children harbouring a high Lactobacillus count. Among children, the presence of lactobacilli in coronal caries is incontestable. Among adults, lactobacilli are found in root caries. Since 1999, taxonomical revisions make it difficult to interpret the results obtained in the numerous previous studies carried out on the identification of oral lactobacilli, but whatever the sampling method or the identification technique, the carious site or the age of sampled subjects, most species belong to the Lactobacillus casei group. This is important because if a specific correlation can be found between few species of lactobacilli and caries a better understanding of their properties could allow the development of new tools for prevention. PMID:19088910

  20. Stability of lactobacilli encapsulated in various microbial polymers.

    PubMed

    Jiménez-Pranteda, María Luján; Poncelet, Denis; Náder-Macías, María Elena; Arcos, Antonio; Aguilera, Margarita; Monteoliva-Sánchez, Mercedes; Ramos-Cormenzana, Alberto

    2012-02-01

    Various microbial polymers, namely xanthan gum, gellan gum, pullulan gum and jamilan, were tested as a suitable encapsulating material for Lactobacillus plantarum CRL 1815 and Lactobacillus rhamnosus ATCC 53103. Resulting capsules were also studied for their pH and simulated gastrointestinal conditions tolerance. The morphology of the microcapsules was studied using scanning electron microscopy. pH tolerance was tested at pH 2.0, 3.5, 5.0 and 6.5 over a 6h incubation period. Simulated gastrointestinal conditions were assayed with simulated gastric and pancreatic juices and simulated bile over a 24h incubation period. Suspensions of probiotic organisms were used as a control. The results from encapsulation with microbial polymers indicate that mixtures of 1% xanthan gum with 0.75% gellan gum and 1% jamilan with 1% gellan gum were the most suitable for microencapsulation. Results for the pH tolerance tests showed no improvement in the viability of cells in relation to the control, except for pH 2.0 where lactobacilli encapsulated in xanthan:gellan gum (1%:0.75%) prolonged their viability by 6h exposure. Xanthan:gellan gum (1%:0.75%) was the most effective of the encapsulating materials tested in protecting L. plantarum and L. rhamnosus against simulated bile, improving its viability in 1-2 logCFU when compared with control. The results of this study suggest that microbial polymers are an interesting source of encapsulating material that should be taken into account for prospective studies of probiotic encapsulation for oral delivery applications.

  1. Conversion of Methionine to Thiols by Lactococci, Lactobacilli, and Brevibacteria†

    PubMed Central

    Dias, Benjamin; Weimer, Bart

    1998-01-01

    Methanethiol has been strongly associated with desirable Cheddar cheese flavor and can be formed from the degradation of methionine (Met) via a number of microbial enzymes. Methionine γ-lyase is thought to play a major role in the catabolism of Met and generation of methanethiol in several species of bacteria. Other enzymes that have been reported to be capable of producing methanethiol from Met in lactic acid bacteria include cystathionine β-lyase and cystathionine γ-lyase. The objective of this study was to determine the production, stability, and activities of the enzymes involved in methanethiol generation in bacteria associated with cheese making. Lactococci and lactobacilli were observed to contain high levels of enzymes that acted primarily on cystathionine. Enzyme activity was dependent on the concentration of sulfur amino acids in the growth medium. Met aminotransferase activity was detected in all of the lactic acid bacteria tested and α-ketoglutarate was used as the amino group acceptor. In Lactococcus lactis subsp. cremoris S2, Met aminotransferase was repressed with increasing concentrations of Met in the growth medium. While no Met aminotransferase activity was detected in Brevibacterium linens BL2, it possessed high levels of l-methionine γ-lyase that was induced by addition of Met to the growth medium. Met demethiolation activity at pH 5.2 with 4% NaCl was not detected in cell extracts but was detected in whole cells. These data suggest that Met degradation in Cheddar cheese will depend on the organism used in production, the amount of enzyme released during aging, and the amount of Met in the matrix. PMID:9726877

  2. Short term effect of mechanical plaque control on salivary concentration of S. mutans and lactobacilli.

    PubMed

    Wikner, S

    1986-08-01

    All visible plaque was professionally removed from teeth of 40 children who were highly infected with S. mutans and lactobacilli. Shortly before and after the removal of plaque the concentrations of those bacteria were assessed in saliva stimulated by chewing. S. mutans and lactobacilli correlated well at baseline but not after plaque elimination, e.g. more than 80% of children who were heavily infected with S. mutans could be identified by a lactobacillus test at baseline. After the elimination of plaque, the mean concentration of S. mutans dropped by 64% but lactobacilli remained unchanged. The results indicate that oral hygiene measures taken by the patient prior to sampling of saliva may mask the true concentration of salivary S. mutans and complicate the identification of high caries risk patients.

  3. Lactobacilli Dominance and Vaginal pH: Why Is the Human Vaginal Microbiome Unique?

    PubMed Central

    Miller, Elizabeth A.; Beasley, DeAnna E.; Dunn, Robert R.; Archie, Elizabeth A.

    2016-01-01

    The human vaginal microbiome is dominated by bacteria from the genus Lactobacillus, which create an acidic environment thought to protect women against sexually transmitted pathogens and opportunistic infections. Strikingly, lactobacilli dominance appears to be unique to humans; while the relative abundance of lactobacilli in the human vagina is typically >70%, in other mammals lactobacilli rarely comprise more than 1% of vaginal microbiota. Several hypotheses have been proposed to explain humans' unique vaginal microbiota, including humans' distinct reproductive physiology, high risk of STDs, and high risk of microbial complications linked to pregnancy and birth. Here, we test these hypotheses using comparative data on vaginal pH and the relative abundance of lactobacilli in 26 mammalian species and 50 studies (N = 21 mammals for pH and 14 mammals for lactobacilli relative abundance). We found that non-human mammals, like humans, exhibit the lowest vaginal pH during the period of highest estrogen. However, the vaginal pH of non-human mammals is never as low as is typical for humans (median vaginal pH in humans = 4.5; range of pH across all 21 non-human mammals = 5.4–7.8). Contrary to disease and obstetric risk hypotheses, we found no significant relationship between vaginal pH or lactobacilli relative abundance and multiple metrics of STD or birth injury risk (P-values ranged from 0.13 to 0.99). Given the lack of evidence for these hypotheses, we discuss two alternative explanations: the common function hypothesis and a novel hypothesis related to the diet of agricultural humans. Specifically, with regard to diet we propose that high levels of starch in human diets have led to increased levels of glycogen in the vaginal tract, which, in turn, promotes the proliferation of lactobacilli. If true, human diet may have paved the way for a novel, protective microbiome in human vaginal tracts. Overall, our results highlight the need for continuing research on non

  4. Lactobacilli Dominance and Vaginal pH: Why Is the Human Vaginal Microbiome Unique?

    PubMed

    Miller, Elizabeth A; Beasley, DeAnna E; Dunn, Robert R; Archie, Elizabeth A

    2016-01-01

    The human vaginal microbiome is dominated by bacteria from the genus Lactobacillus, which create an acidic environment thought to protect women against sexually transmitted pathogens and opportunistic infections. Strikingly, lactobacilli dominance appears to be unique to humans; while the relative abundance of lactobacilli in the human vagina is typically >70%, in other mammals lactobacilli rarely comprise more than 1% of vaginal microbiota. Several hypotheses have been proposed to explain humans' unique vaginal microbiota, including humans' distinct reproductive physiology, high risk of STDs, and high risk of microbial complications linked to pregnancy and birth. Here, we test these hypotheses using comparative data on vaginal pH and the relative abundance of lactobacilli in 26 mammalian species and 50 studies (N = 21 mammals for pH and 14 mammals for lactobacilli relative abundance). We found that non-human mammals, like humans, exhibit the lowest vaginal pH during the period of highest estrogen. However, the vaginal pH of non-human mammals is never as low as is typical for humans (median vaginal pH in humans = 4.5; range of pH across all 21 non-human mammals = 5.4-7.8). Contrary to disease and obstetric risk hypotheses, we found no significant relationship between vaginal pH or lactobacilli relative abundance and multiple metrics of STD or birth injury risk (P-values ranged from 0.13 to 0.99). Given the lack of evidence for these hypotheses, we discuss two alternative explanations: the common function hypothesis and a novel hypothesis related to the diet of agricultural humans. Specifically, with regard to diet we propose that high levels of starch in human diets have led to increased levels of glycogen in the vaginal tract, which, in turn, promotes the proliferation of lactobacilli. If true, human diet may have paved the way for a novel, protective microbiome in human vaginal tracts. Overall, our results highlight the need for continuing research on non

  5. Homo- and heterofermentative lactobacilli differently affect sugarcane-based fuel ethanol fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antagonism between by yeast and lactobacilli is largely dependent on the initial population of each organism. While homo-fermentative lactobacillus present higher inhibitory effect upon yeast when in equal cell number, in industrial fuel ethanol conditions where high yeast cell densities prevail...

  6. Exogenous lactobacilli mitigate microbial changes associated with grain fermentation in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cereal grains are often included in equine diets. Sugars and starch in grains can be digested and absorbed in the small intestine, but a high proportion of grain in the diet can allow starch to reach the hindgut, disturbing the microbial ecology. Streptococci and lactobacilli both catabolize starch ...

  7. Isolation of Tannin-Degrading Lactobacilli from Humans and Fermented Foods

    PubMed Central

    Osawa, Ro; Kuroiso, Keiko; Goto, Satoshi; Shimizu, Akira

    2000-01-01

    Lactobacilli with tannase activity were isolated from human feces and fermented foods. A PCR-based taxonomic assay revealed that the isolates belong to Lactobacillus plantarum, L. paraplantarum, and L. pentosus. Additional studies on a range of Lactobacillus species from established culture collections confirmed that this enzymatic activity is a phenotypic property common to these three species. PMID:10877812

  8. Development of a Lactobacillus Specific T-RFLP Method to Determine Lactobacilli Diversity in Complex Samples

    PubMed Central

    Chen, Long; Teasdale, Matt T.; Kaczmarczyk, Melissa M.; Freund, Gregory G.; Miller, Michael J.

    2012-01-01

    Terminal restriction fragment length polymorphism (T-RFLP) analysis has been widely used for studying microbial communities. However, most T-RFLP assays use 16S rDNA as the target and are unable to accurately characterize a microbial subpopulation. In this study, we developed a novel T-RFLP protocol based on Lactobacillus hsp60 to rapidly characterize and compare lactobacilli composition. The theoretical terminal restriction fragment (TRF) profiles were calculated from 769 Lactobacillus hsp60 sequences from online databases. In silico digestion with restriction endonucleases AluI and TacI on hsp60 amplicons generated 83 distinct TRF patterns, of which, 70 were species specific. To validate the assay, five previously sequenced lactobacilli were cultured independently, mixed at known concentrations and subjected to analysis by T-RFLP. All five strains generated the predicted TRFs and a qualitative consistent relationship was revealed. We performed the T-RFLP protocol on fecal samples from mice fed 6 different diets (n=4). Principal component analysis and agglomerative hierarchical clustering revealed that the lactobacilli community was strongly connected to dietary supplementation. Our study demonstrates the potential for using Lactobacillus specific T-RFLP to characterize lactobacilli communities in complex samples. PMID:22981747

  9. Cervicovaginal fluid and semen block the microbicidal activity of hydrogen peroxide produced by vaginal lactobacilli

    PubMed Central

    2010-01-01

    Background H2O2 produced by vaginal lactobacilli is believed to protect against infection, and H2O2-producing lactobacilli inactivate pathogens in vitro in protein-free salt solution. However, cervicovaginal fluid (CVF) and semen have significant H2O2-blocking activity. Methods We measured the H2O2 concentration of CVF and the H2O2-blocking activity of CVF and semen using fluorescence and in vitro bacterial-exposure experiments. Results The mean H2O2 measured in fully aerobic CVF was 23 ± 5 μM; however, 50 μM H2O2 in salt solution showed no in vitro inactivation of HSV-2, Neisseria gonorrhoeae, Hemophilus ducreyii, or any of six BV-associated bacteria. CVF reduced 1 mM added H2O2 to an undetectable level, while semen reduced 10 mM added H2O2 to undetectable. Moreover, the addition of just 1% CVF supernatant abolished in vitro pathogen-inactivation by H2O2-producing lactobacilli. Conclusions Given the H2O2-blocking activity of CVF and semen, it is implausible that H2O2-production by vaginal lactobacilli is a significant mechanism of protection in vivo. PMID:20482854

  10. Sample handling factors affecting the enumeration of lactobacilli and cellulolytic bacteria in equine feces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives were to compare media types and evaluate the effects of fecal storage time and temperature on the enumeration of cellulolytic bacteria and lactobacilli from horses. Fecal samples were collected from horses (n = 3) and transported to the lab (CO2, 37 ºC, 0.5 h). The samples were assign...

  11. Two strains of nonstarter lactobacilli increased the production of flavor compounds in soft cheeses.

    PubMed

    Milesi, M M; Wolf, I V; Bergamini, C V; Hynes, E R

    2010-11-01

    The contribution to flavor generation and secondary proteolysis of 2 strains of mesophilic lactobacilli isolated from cheese was studied. Miniature soft cheeses (200 g) were produced with or without the inclusion of a culture of Lactobacillus plantarum I91 or Lactobacillus casei I90 in the starter composed of Streptococcus thermophilus. During ripening, cheeses containing the added lactobacilli showed an increased content of total free amino acids, but this increase was only significant in cheeses with Lb. plantarum I91. In addition, free amino acid profiles were modified by selective increases of some amino acids, such as Asp, Ser, Arg, Leu, and Phe. Cheeses inoculated with Lb. plantarum I91 or Lb. casei I90 were also characterized by a significantly higher concentration of diacetyl, a key flavor compound, and an increased content of acetoin. Results suggest an increase in the catabolism of either citrate or aspartate, with the production of the derived aroma compounds. Overall, aspartate content increased in both lactobacilli-added cheeses, whereas citrate was more or less constant, suggesting that aspartate could be the source of increased diacetyl and acetoin. A triangle aroma test showed that the addition of the lactobacilli strains significantly changed the sensory attributes of cheeses. At least 11 of 12 panelists commented that the aroma of cheeses with adjuncts was more buttery than that of control cheeses, which is desirable in most soft cheeses. Both Lb. plantarum I91 and Lb. casei I90 performed well as adjunct cultures by influencing cheese aroma development and cheese proteolysis.

  12. Presence of drug resistance in intestinal lactobacilli of dairy and human origin in Turkey.

    PubMed

    Cataloluk, Osman; Gogebakan, Bulent

    2004-07-01

    The prevalence of different resistance genes was investigated in lactobacilli of human and dairy origin by PCR. The presence of erm, van, tet, and cat-TC genes were determined in 16 raw milk, 15 cream, 10 yogurt, 50 hand-made cheese, and 20 industrially produced white-cheese samples of dairy origin and 16 mouth, 32 fecal, and 36 vaginal samples from different subjects of human origin. Lactobacilli of dairy and human origin were found to carry only erm(B) and tet(M) genes. The majority of the isolates, Lactobacillus crispatus (61), Lactobacillus gasseri (49), Lactobacillus plantarum (80) studied were found to harbor either erm(B) or tet(M) gene or both. No resistant lactobacilli was found in raw-milk and cream samples. All the human fecal samples and the majority of vaginal (29 of 36) and mouth (10 of 14) samples were found to carry the resistance genes. While a third of the hand-made cheeses carried resistant lactobacilli only one industrially produced cheese was found to carry resistant lactobacilli. Furthermore, the genes were found in the non-starter species, Lactobacillus acidophilus and Lb. plantarum, indicating that industrially produced cheeses in this respect could be considered more favorable. These results indicate that drug resistance seems to be very common in Turkey. Even though the number of dairy samples harboring the resistance genes (17 of 111) is smaller in regards to human samples, 10% of them were still found to carry the resistance genes as well. The presence of the resistance genes in majority of the samples of human origin and in minority of the samples of dairy origin indicates that drug resistance may be acquired in the intestinal tract during passage and spread to dairy products by the hands of workers during production.

  13. Nonstarter lactobacilli isolated from soft and semihard Argentinean cheeses: genetic characterization and resistance to biological barriers.

    PubMed

    Ugarte, Mariana Bude; Guglielmotti, Daniela; Giraffa, Giorgio; Reinheimer, Jorge; Hynes, Erica

    2006-12-01

    Nonstarter lactic acid bacteria isolated from Argentinean cheeses were identified and characterized by focusing on their resistance to biological barriers, along with other physiological features of potential interest, in the search for future probiotic organisms. Lactobacilli were enumerated and isolated from semihard and soft cheeses made with multistrain Streptococcus thermophilus starters. Lactobacilli counts in 1-week-old cheeses were between 10(5) and 10(7) CFU/g and then reached 10(7) CFU/ g in all 1-month samples, while streptococci were always above 10(9) CFU/g. A total number of 22 lactobacilli isolates were retained, identified, and characterized by in vitro tests. Species identity was determined by carbohydrate metabolism and species-specific PCR assays. Genetic diversity was explored by random amplified polymorphic DNA (RAPD) PCR analysis. The Lactobacillus strains were assigned to the species L. casei, L. plantarum, L. rhamnosus, L. curvatus, L. fermentum, and L. perolens. All the strains studied tolerated 25 ppm of lysozyme, and most of them showed resistance to 0.3% bile. After incubation in gastric solution (pH 2.0), counts decreased by several log units, ranging from 3.2 to 7.0. The strains were able to grow in the presence of bile salts, but only three isolates were capable of deconjugation. The nonstarter lactobacilli that were assayed fermented the prebiotic substrates (especially lactulose and inulin). Some strains showed high cell hydrophobicity and beta-galactosidase activity, as well as inhibitory activity against pathogenic bacteria. It was concluded that most of the lactobacilli isolated in this study demonstrated resistance to biological barriers and physiological characteristics compatible with probiotic properties, which make them suitable for further research in in vivo studies aimed at identifying new probiotic organisms.

  14. Determining Antioxidant Activities of Lactobacilli Cell-Free Supernatants by Cellular Antioxidant Assay: A Comparison with Traditional Methods

    PubMed Central

    Xing, Jiali; Wang, Gang; Zhang, Qiuxiang; Liu, Xiaoming; Gu, Zhennan; Zhang, Hao; Chen, Yong Q.; Chen, Wei

    2015-01-01

    Antioxidant activity of lactic acid bacteria is associated with multiple health-protective effects. Traditional indexes of chemical antioxidant activities poorly reflect the antioxidant effects of these bacteria in vivo. Cellular antioxidant activity (CAA) assay was used in this study to determine the antioxidant activity of cell-free supernatants (CFSs) of 10 Lactobacillus strains. The performance of the CAA assay was compared with that of four chemical antioxidant activity assays, namely, DPPH radical scavenging, hydroxyl radical scavenging (HRS), reducing power (RP), and inhibition of linoleic acid peroxidation (ILAP). Results of the CAA assay were associated with those of DPPH and ILAP assays, but not with those of RP and HRS assays. The inter- and intra-specific antioxidant activities of CFS were characterized by chemical and CAA assays. L. rhamnosus CCFM 1107 displayed a high antioxidative effect similar to positive control L. rhamnosus GG ATCC 53103 in all of the assays. The CAA assay is a potential method for the detection of antioxidant activities of lactobacilli CFSs. PMID:25789875

  15. Effects of a lactobacilli, oligosaccharide and organic germanium intake on the immune responses of mice.

    PubMed

    Nakamura, Takashi; Saito, Miki; Aso, Hisashi

    2012-01-01

    The organic germanium compound, Ge-132, has immune-modulating effects. We evaluated the symbiotic effects of Ge-132 with lactobacilli and oligosaccharide (LB/OS) on the immune responses of mice. The highest fecal IgA levels were observed in the mice receiving a low concentration of Ge-132 with LB/OS for 8 weeks. Our data suggest that LB/OS with a low concentration of Ge-132 stimulated the intestinal immunity.

  16. Lactobacilli and Bifidobacteria in Human Breast Milk: Influence of Antibiotherapy and Other Host and Clinical Factors

    PubMed Central

    Soto, Ana; Martín, Virginia; Jiménez, Esther; Mader, Isabelle; Rodríguez, Juan M.; Fernández, Leonides

    2014-01-01

    ABSTRACT Objective: The objective of this work was to study the lactobacilli and bifidobacteria population in human milk of healthy women, and to investigate the influence that several factors (including antibioteraphy during pregnancy and lactation, country and date of birth, delivery mode, or infant age) may exert on such population. Methods: A total of 160 women living in Germany or Austria provided the breast milk samples. Initially, 66 samples were randomly selected and cultured on MRS-Cys agar plates. Then, the presence of DNA from the genera Lactobacillus and Bifidobacterium, and from most of the Lactobacillus and Bifidobacterium species that were isolated, was assessed by qualitative polymerase chain reaction (PCR) using genus- and species-specific primers. Results: Lactobacilli and bifidobacteria could be isolated from the milk of 27 (40.91%) and 7 (10.61%), respectively, of the 66 cultured samples. On the contrary, Lactobacillus and Bifidobacterium sequences were detected by PCR in 108 (67.50%) and 41 (25.62%), respectively, of the 160 samples analyzed. The Lactobacillus species most frequently isolated and detected was L salivarius (35.00%), followed by L fermentum (25.00%) and L gasseri (21.88%), whereas B breve (13.75%) was the bifidobacterial species most commonly recovered and whose DNA was most regularly found. The number of lactobacilli- or bifidobacteria-positive samples was significantly lower in women who had received antibiotherapy during pregnancy or lactation. Conclusions: Our results suggest that either the presence of lactobacilli and/or bifidobacteria or their DNA may constitute good markers of a healthy human milk microbiota that has not been altered by the use of antibiotics. PMID:24590211

  17. Vaginal pH and Microbicidal Lactic Acid When Lactobacilli Dominate the Microbiota

    PubMed Central

    O’Hanlon, Deirdre E.; Moench, Thomas R.; Cone, Richard A.

    2013-01-01

    Lactic acid at sufficiently acidic pH is a potent microbicide, and lactic acid produced by vaginal lactobacilli may help protect against reproductive tract infections. However, previous observations likely underestimated healthy vaginal acidity and total lactate concentration since they failed to exclude women without a lactobacillus-dominated vaginal microbiota, and also did not account for the high carbon dioxide, low oxygen environment of the vagina. Fifty-six women with low (0-3) Nugent scores (indicating a lactobacillus-dominated vaginal microbiota) and no symptoms of reproductive tract disease or infection, provided a total of 64 cervicovaginal fluid samples using a collection method that avoided the need for sample dilution and rigorously minimized aerobic exposure. The pH of samples was measured by microelectrode immediately after collection and under a physiological vaginal concentration of CO2. Commercial enzymatic assays of total lactate and total acetate concentrations were validated for use in CVF, and compared to the more usual HPLC method. The average pH of the CVF samples was 3.5 ± 0.3 (mean ± SD), range 2.8-4.2, and the average total lactate was 1.0% ± 0.2% w/v; this is a five-fold higher average hydrogen ion concentration (lower pH) and a fivefold higher total lactate concentration than in the prior literature. The microbicidal form of lactic acid (protonated lactic acid) was therefore eleven-fold more concentrated, and a markedly more potent microbicide, than indicated by prior research. This suggests that when lactobacilli dominate the vaginal microbiota, women have significantly more lactic acid-mediated protection against infections than currently believed. Our results invite further evaluations of the prophylactic and therapeutic actions of vaginal lactic acid, whether provided in situ by endogenous lactobacilli, by probiotic lactobacilli, or by products that reinforce vaginal lactic acid. PMID:24223212

  18. Vaginal pH and microbicidal lactic acid when lactobacilli dominate the microbiota.

    PubMed

    O'Hanlon, Deirdre E; Moench, Thomas R; Cone, Richard A

    2013-01-01

    Lactic acid at sufficiently acidic pH is a potent microbicide, and lactic acid produced by vaginal lactobacilli may help protect against reproductive tract infections. However, previous observations likely underestimated healthy vaginal acidity and total lactate concentration since they failed to exclude women without a lactobacillus-dominated vaginal microbiota, and also did not account for the high carbon dioxide, low oxygen environment of the vagina. Fifty-six women with low (0-3) Nugent scores (indicating a lactobacillus-dominated vaginal microbiota) and no symptoms of reproductive tract disease or infection, provided a total of 64 cervicovaginal fluid samples using a collection method that avoided the need for sample dilution and rigorously minimized aerobic exposure. The pH of samples was measured by microelectrode immediately after collection and under a physiological vaginal concentration of CO2. Commercial enzymatic assays of total lactate and total acetate concentrations were validated for use in CVF, and compared to the more usual HPLC method. The average pH of the CVF samples was 3.5 ± 0.3 (mean ± SD), range 2.8-4.2, and the average total lactate was 1.0% ± 0.2% w/v; this is a five-fold higher average hydrogen ion concentration (lower pH) and a fivefold higher total lactate concentration than in the prior literature. The microbicidal form of lactic acid (protonated lactic acid) was therefore eleven-fold more concentrated, and a markedly more potent microbicide, than indicated by prior research. This suggests that when lactobacilli dominate the vaginal microbiota, women have significantly more lactic acid-mediated protection against infections than currently believed. Our results invite further evaluations of the prophylactic and therapeutic actions of vaginal lactic acid, whether provided in situ by endogenous lactobacilli, by probiotic lactobacilli, or by products that reinforce vaginal lactic acid.

  19. Lactobacilli Activate Human Dendritic Cells that Skew T Cells Toward T Helper 1 Polarization

    DTIC Science & Technology

    2005-01-06

    symbiotic bacteria to perform their critical functions in host nutrition, intestinal permeability, and protection against foreign, pathogenic microbes...memory T cells to Th1 responses, which are proinflammatory and lead to robust im- munity against infections and other diseases (27). Interestingly, IL-12...as safe when ad- ministered as probiotics . Because DCs can naturally or therapeu- tically encounter lactobacilli, we investigated the effects of

  20. Headspace flavour compounds produced by yeasts and lactobacilli during fermentation of preferments and bread doughs.

    PubMed

    Torner, M J; Martínez-Anaya, M A; Antuña, B; Benedito de Barber, C

    1992-01-01

    Production of volatile flavour compounds during fermentation with pure cultures of Saccharomyces cerevisiae and Candida guilliermondii, Lactobacillus brevis and Lactobacillus plantarum have been investigated, using wheat doughs and several preferements as substrates. For yeast, preferments consisted of 10% (w/v) glucose, maltose and sucrose solutions, whereas for lactobacilli they consisted of supplemented and unsupplemented (3% and 10% (w/v)) glucose solutions, and a 10% (w/v) wheat flour slurry. Seven volatile compounds (acetaldehyde, acetone, ethyl acetate, ethanol, hexanal+isobutyl alcohol, and propanol) were detected when using yeasts. All these compounds, except propanol, appeared for all the substrates assayed, with ethanol as the predominant component. Generally, S. cerevisiae produced higher amounts of the different components than C. guilliermondii. Both yeasts produced larger amounts of volatile flavour compounds during fermentation in glucose and sucrose solutions than in maltose or wheat dough. In general the yeasts examined produced more flavour components than the lactobacilli. For the lactobacilli the highest number of volatile flavour compounds were observed for substrates containing flour.

  1. Use of cheese whey for biomass production and spray drying of probiotic lactobacilli.

    PubMed

    Lavari, Luisina; Páez, Roxana; Cuatrin, Alejandra; Reinheimer, Jorge; Vinderola, Gabriel

    2014-08-01

    The double use of cheese whey (culture medium and thermoprotectant for spray drying of lactobacilli) was explored in this study for adding value to this wastewater. In-house formulated broth (similar to MRS) and dairy media (cheese and ricotta whey and whey permeate) were assessed for their capacity to produce biomass of Lactobacillus paracasei JP1, Lb. rhamnosus 64 and Lb. gasseri 37. Simultaneously, spray drying of cheese whey-starch solution (without lactobacilli cells) was optimised using surface response methodology. Cell suspensions of the lactobacilli, produced in in house-formulated broth, were spray-dried in cheese whey-starch solution and viability monitored throughout the storage of powders for 2 months. Lb. rhamnosus 64 was able to grow satisfactorily in at least two of the in-house formulated culture media and in the dairy media assessed. It also performed well in spray drying. The performance of the other strains was less satisfactory. The growth capacity, the resistance to spray drying in cheese whey-starch solution and the negligible lost in viability during the storage (2 months), makes Lb. rhamnosus 64 a promising candidate for further technological studies for developing a probiotic dehydrated culture for foods, utilising wastewaters of the dairy industry (as growth substrate and protectant) and spray drying (a low-cost widely-available technology).

  2. Not only osmoprotectant: betaine increased lactate dehydrogenase activity and L-lactate production in lactobacilli.

    PubMed

    Zou, Huibin; Wu, Zaiqiang; Xian, Mo; Liu, Hui; Cheng, Tao; Cao, Yujin

    2013-11-01

    Lactobacilli are commonly used for industrial production of polymer-grade L-lactic acid. The present study tested the Tween 80 alternative betaine in L-lactate production by several industrial lactobacilli. In flask fermentation of Lactobacillus casei, Lactobacillus buchneri, Lactobacillus lactis and Lactobacillus rhamnosus, the betaine addition (2g/l) had similar osmoprotectant effect with Tween 80 but had increased the lactate dehydrogenase activities and L-lactate production than Tween 80 control. In fed-batch fermentation of L. casei, betaine supplementation improved the L-lactic acid titer to 190 g/l, the yield to 95.5% (g L-lactic acid/g glucose), the productivity to 2.6g/lh, and the optical purity to 97.0%. The results demonstrated that supplementation of Tween 80 alternative - betaine in the fermentation medium is feasible for industrial l-lactic acid fermentation by lactobacilli, which will improve the lactate production but will not increase the process costs and modify any process conditions.

  3. Characterization of tetracycline resistance lactobacilli isolated from swine intestines at western area of Taiwan.

    PubMed

    Chang, Yi-Chih; Tsai, Chen-Yen; Lin, Chuen-Fu; Wang, Yu-Chih; Wang, I-Kuan; Chung, Tung-Ching

    2011-10-01

    To investigate the frequency of tetracycline resistance (Tet-R) lactobacilli in pig intestines, a total of 256 pig colons were analyzed and found to contain typical colonies of Tet-R lactic acid bacteria in every sample, ranging from 3.2 × 10(3) to 6.6 × 10(5) CFU/cm(2). From these samples, a total of 159 isolates of Tet-R lactobacilli were obtained and identified as belonging to 11 species, including Lactobacillus reuteri, Lactobacillus amylovorus, Lactobacillus salivarius, Lactobacillus plantarum, Lactobacillus ruminis, Lactobacillus kefiri, Lactobacillus fermentum, Lactobacillus sakei, Lactobacillus coryniformis, Lactobacillus parabuchneri and Lactobacillus letivazi. Based on the EFSA (2008) breakpoints, all isolates, after MIC analysis, were qualified as Tet-R, from which the significant high Tet-R MIC(50) and MIC(90) values indicated an ecological distribution of Tet-R lactobacilli mostly with high resistance potency in pig colons. PCR-detection identified 5 tet genes in these isolates, the most predominant one being tet (W), followed by tet (M), (L), (K), and (Q). Their detection rates were 82.0%, 22.5%, 14.4%, 8.1% and 0.9%, respectively. Noteworthily, isolates of the same species carrying identical tet gene(s) usually had a wide different MIC values. Furthermore, strain-subtyping of these isolates by REP-PCR demonstrated a notable genotypic biodiversity % (average = 62%).

  4. Isolation, molecular characterization and screening of indigenous lactobacilli for their abilities to produce bioactive conjugated linoleic acid (CLA).

    PubMed

    Dahiya, Dinesh Kumar; Puniya, Anil Kumar

    2017-03-01

    Ingestion of conjugated linoleic acid poised many health benefits; however, amount of CLA one can get through generalized diet in is inadequate in exerting the desired benefits. Therefore, presence of CLA producing lactobacilli in dairy fermented foods has a tremendous potential to increase the CLA content. Therefore, present study was focused to isolate and characterize CLA producing lactobacilli from different dairy products and human faeces. Arguably, 283 lactobacilli were isolated from various sources and tested for CLA production. Fifty-seven CLA producing (≥20 µg/ml) lactobacilli were selected from screening in de Man, Rogosa and Sharpe (MRS) broth and reconstituted with skim milk (SM), supplemented with 0.5 mg/ml of linoleic acid. Positive strains were classified into-L. plantarum (44%), L. gasseri (30%), L. fermentum (21%) and L. salivarius (5%) species. Nineteen most efficient strains (CLA ≥25 µg/ml) were further assessed in SM for CLA production. Total 08 strains produced significantly higher CLA in SM than MRS and also produced cis 9, trans 11, trans 10, cis 12 and trans 9, trans 11 isomers. Overall, L. plantarum HIF15 was reported as the best producer of CLA and other 08 lactobacilli may be utilized for the formulation of CLA-enriched functional foods to support these bacteria to synthesize CLA in the human gut.

  5. Enhanced growth of lactobacilli and bioconversion of isoflavones in biotin-supplemented soymilk upon ultrasound-treatment.

    PubMed

    Ewe, Joo-Ann; Wan Abdullah, Wan-Nadiah; Bhat, Rajeev; Karim, A A; Liong, Min-Tze

    2012-01-01

    This study aimed at utilizing ultrasound treatment to further enhance the growth of lactobacilli and their isoflavone bioconversion activities in biotin-supplemented soymilk. Strains of lactobacilli (Lactobacillus acidophilus BT 1088, L. fermentum BT 8219, L. acidophilus FTDC 8633, L. gasseri FTDC 8131) were treated with ultrasound (30 kHz, 100 W) at different amplitudes (20%, 60% and 100%) for 60, 120 and 180 s prior to inoculation and fermentation in biotin-soymilk. The treatment affected the fatty acids chain of the cellular membrane lipid bilayer, as shown by an increased lipid peroxidation (P<0.05). This led to increased membrane fluidity and subsequently, membrane permeability (P<0.05). The permeabilized cellular membranes had facilitated nutrient internalization and subsequent growth enhancement (P<0.05). Higher amplitudes and longer durations of the treatment promoted growth of lactobacilli in soymilk, with viable counts exceeding 9 log CFU/mL. The intracellular and extracellular β-glucosidase specific activities of lactobacilli were also enhanced (P<0.05) upon ultrasound treatment, leading to increased bioconversion of isoflavones in soymilk, particularly genistin and malonyl genistin to genistein. Results from this study show that ultrasound treatment on lactobacilli cells promotes (P<0.05) the β-glucosidase activity of cells for the benefit of enhanced (P<0.05) isoflavone glucosides bioconversion to bioactive aglycones in soymilk.

  6. pH gradient and distribution of streptococci, lactobacilli, prevotellae, and fusobacteria in carious dentine

    PubMed Central

    Nguyen, Ky-Anh T.; Browne, Gina V.; Simonian, Mary; Hunter, Neil

    2013-01-01

    Objectives Caries process comprises acidogenic and aciduric bacteria that are responsible for lowering the pH and subsequent destruction of hydroxyapatite matrix in enamel and dentine. The aim of this study was to identify the correlation between the pH gradient of a carious lesion and proportion and distribution of four bacterial genera; lactobacilli, streptococci, prevotellae, and fusobacteria with regard to total load of bacteria. Materials and methods A total of 25 teeth with extensive dentinal caries were sampled in sequential layers. Using quantitative real-time PCR of 16S rRNA gene, we quantified the total load of bacteria as well as the proportion of the abovementioned genera following pH measurement of each sample with a fine microelectrode. Results We demonstrated the presence of a pH gradient across the lesion with a strong association between the quantity of lactobacilli and the lowest pH range (pH 4.5–5.0; p = 0.003). Streptococci had a tendency to occupy the most superficial aspect of the carious lesion but showed no correlation to any pH value. Prevotellae showed clear preference for the pH range 5.5–6.0 (p = 0.042). The total representation of these four genera did not reach more than one quarter of the total bacterial load in most carious samples. Conclusion We revealed differential colonization behavior of bacteria with respect to pH gradient and a lower than expected abundance of lactobacilli and streptococci in established carious lesions. The data indicate the numerical importance of relatively unexplored taxa within the lesion of dentinal caries. Clinical relevance The gradient nature of pH in the lesion as well as colonization difference of examined bacterial taxa with reference to pH provides a new insight in regard to conservative caries management. PMID:23771212

  7. Characterizing Diversity of Lactobacilli Associated with Severe Early Childhood Caries: A Study Protocol

    PubMed Central

    Argimón, Silvia; Schön, Catherine N.; Saraithong, Prakaimuk; Caufield, Page W.

    2015-01-01

    Lactobacilli have been consistently associated with dental caries for decades; however, knowledge of this group of bacteria in the etiology of the disease is limited to quantitative elucidation. Nowadays, explicit identification of oral Lactobacillus species is possible, despite their taxonomic complexity. Here we describe a combined approach involving both cultivation and genetic methods to ascertain and characterize the diversity and abundance of the Lactobacillus population in the oral cavities of children with severe early childhood caries (S-ECC). Eighty 3- to 6-year-old children (40 S-ECC and 40 caries free) who were seeking dental care at the Pediatric Dental Clinic of Bellevue Hospital in New York City were invited to participate in this study. Clinical data on socio-demographic information and oral health behavior were obtained from the primary caregiver. The data included a detailed dental examination, children’s medical history, and a questionnaire survey. Combined non-stimulated saliva and supra-gingival plaque samples were collected from each child and cultivated on selective media for quantitative measures of lactobacilli levels. The procedure for Lactobacillus species screening will include the random selection of 50 colonies per plate, extraction of DNA from each colony, and genotyping by arbitrarily primed polymerase chain reaction (AP-PCR). Each unique Lactobacillus AP-PCR genotype will be selected for taxonomic assessment by 16S rRNA gene sequencing analysis. Lactobacillus species will be identified by comparing the 16S rRNA sequences with the Ribosomal Database and the Human Oral Microbiome Database. Meanwhile, the same set of clinical samples will be independently subjected to genomic DNA isolation, 16S rRNA amplification with Lactobacillus genus-specific primers, sequencing, and taxonomic identification, both at genus and species levels with a customized pipeline. The distribution and phylogenetic differences of these Lactobacillus species

  8. Determination of Antibacterial and Technological Properties of Vaginal Lactobacilli for Their Potential Application in Dairy Products

    PubMed Central

    Siroli, Lorenzo; Patrignani, Francesca; Serrazanetti, Diana I.; Parolin, Carola; Ñahui Palomino, Rogers A.; Vitali, Beatrice; Lanciotti, Rosalba

    2017-01-01

    Functional foods could differently affect human health in relation to the gender. Recent studies have highlighted the anti-Candida and anti-Chlamydia activities of some Lactobacillus strains isolated from the vagina of healthy women. Considering these important beneficial activities on women's health, the preparation of functional food containing active vaginal lactobacilli can represent a great scientific challenge for the female gender. In this context, the aim of this work was to study some functional and technological properties of 17 vaginal strains belonging to the species Lactobacillus crispatus, Lactobacillus gasseri, and Lactobacillus vaginalis in the perspective to include them in dairy products. The antagonistic activities against the pathogenic and spoilage species associated to food products and against the principal etiological agents of the genitourinary tract infections were evaluated. Moreover, the vaginal lactobacilli were characterized for their antibiotic resistance, and for their fermentation kinetics and viability during the refrigerated storage in milk. Finally, the volatile molecule profiles of the obtained fermented milks were determined. The results showed that several strains, mainly belonging to the species Lactobacillus crispatus, exhibited a significant antagonistic activity against spoilage and pathogenic microorganisms of food interest, as well as against urogenital pathogens. All the vaginal lactobacilli showed antimicrobial activity against strains belonging to the foodborne pathogenic species Listeria monocytogenes, Listeria innocua, Eenterococcus faecalis and Escherichia coli. In addition, most of the Lactobacillus strains were active toward the main pathogens responsible of vaginal and urinary tract infections including Staphylococcus aureus, Enterococcus faecium, Gardnerella vaginalis, and Proteus mirabilis. The antimicrobial activity can be attributed to the high production of organic acids. The fermentation kinetics in milk

  9. Lactobacilli, bifidobacteria and E. coli nissle induce pro- and anti-inflammatory cytokines in peripheral blood mononuclear cells

    PubMed Central

    Helwig, Ulf; Lammers, Karen M; Rizzello, Fernando; Brigidi, Patricia; Rohleder, Verena; Caramelli, Elisabetta; Gionchetti, Paolo; Schrezenmeir, Juergen; Foelsch, Ulrich R; Schreiber, Stefan; Campieri, Massimo

    2006-01-01

    AIM: To investigate whether the stimulation of peripheral blood mononuclear cells (PBMNC) with the cell debris and cell extraction of different probiotic strains is similar or species specific. METHODS: Three strains of bifidobacteria, 4 strains of lactobacilli, and E. coli nissle were sonicated and centrifuged in order to divide them into cell extract and cell debris. PBMNC were separated by density gradient and incubated for 36 h with either the cell debris or the cell extract of single strains of probiotic bacteria in doses from 102 to 108 CFU/mL. Cell supernatants were taken and interleukin (IL)-10, IL-1β, and tumor necosis factor (TNF)-α were determined by ELISA. RESULTS: Depending on the species super-family, the strains had different stimulation patterns. Except for both L. casei strains, the cell extract of bifidobacteria and lactobacilli had less stimulating capacity than cell debris, whereas the cell extract of E. coli nissle had similar stimulating properties to that of the cell debris of the strain and significantly more stimulating capacity than that of bifidobacteria and lactobacilli. The cell debris of bifidobacteria stimulated more cytokine release than the cell debris of lactobacilli. The cell debris of lactobacilli did not have a stimulating capacity when lower concentrations were used. Neither cell extraction nor cell debris had an inhibitory effect on the production of the tested cytokines by stimulated PBMNC. CONCLUSION: The incubation of probiotic strains, which have been used in clinical trials for inflammatory diseases, with immunocompetent cells leads to different species specific reactions. High IL-10 response to cell debris of bifidobacteria and E. coli nissle can be found. This corresponds to positive effects of bifidobacteria and E. coli nissle in clinical trials for inflammatory bowel disease compared to negative outcomes obtained with lactobacilli. PMID:17009396

  10. [Comparative study of effects of Escherichia coli M-17 exometabolites and fructooligosaccharides on the growth and antagonistic activity of Lactobacilli].

    PubMed

    Vakkhitov, T Ia; Dobrolezh, O V; Petrov, L N; Verbitskaia, N B; Zadaura, E Iu

    2001-01-01

    Facts concerning the evaluation of the influence of E. coli M17 exometabolites and fructooligosaccharides (FOS) on the growth and antagonistic activity of lactobacilli are presented. As revealed by these facts, preparation "Aktoflor" accelerates the growth of lactobacillary cultures, increases the final yield of biomass and antagonistic activity. E. coli M17 exometabolites contained in "Aktoflor" have been shown to be more active in comparison with FOS. The character of their influence on lactobacilli is discussed and the conclusion is made that the restoration and maintenance of eubiosis is greatly determined by the pool of metabolites excreted by the bacteria.

  11. Sequential fermentation of pearl millet by yeasts and lactobacilli--effect on the antinutrients and in vitro digestibility.

    PubMed

    Khetarpaul, N; Chauhan, B M

    1991-10-01

    Sequential culture fermentation by yeasts (S. diastaticus or S. cerevisiae) at 30 degrees C for 72 hr and then followed by lactobacilli fermentation (L. brevis or L. fermentum) at 30 degrees C for 72 h more resulted in a significant reduction in phytic acid and polyphenol content of pearl millet flour. Fermentation by S. diastaticus and L. brevis combination almost eliminated phytic acid from pearl millet flour. The combinations of S. diastaticus with both the lactobacilli reduced phytic acid more effectively than those of S. cerevisiae. The products fermented by S. cerevisiae and L. brevis and by S. diastaticus and L. brevis combinations had the highest protein and starch digestibility (in vitro).

  12. Characterization of the adherence properties of human Lactobacilli strains to be used as vaginal probiotics.

    PubMed

    Martín, Rebeca; Sánchez, Borja; Suárez, Juan Evaristo; Urdaci, María C

    2012-03-01

    In the present work, the adhesion of 43 human lactobacilli isolates to mucin has been studied. The most adherent strains were selected, and their capacities to adhere to three epithelial cell lines were studied. All intestinal strains and one vaginal isolate adhered to HT-29 cells. The latter was the most adherent to Caco-2 cells, although two of the intestinal isolates were also highly adherent. Moreover, five of the eight strains strongly adhered to HeLa cells. The binding of an Actinomyces neuii clinical isolate to HeLa cells was enhanced by two of the lactobacilli and by their secreted proteins, while those of another two strains almost abolished it. None of the strains were able to interfere with the adhesion of Candida albicans to HeLa cells. The components of the extracellular proteome of all strains were identified by MALDI-TOF/MS. Among them, a collagen-binding A precursor and aggregation-promoting factor-like proteins are suggested to participate on adhesion to Caco-2 and HeLa cells, respectively. In this way, several proteins with LysM domains might explain the ability of some bacterial supernatants to block A. neuii adhesion to HeLa cell cultures. Finally, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) could explain the good adhesion of some strains to mucin.

  13. Suppression of salivary Streptococcus mutans and lactobacilli by topical caries preventive agents.

    PubMed

    Juric, H; Dukic, W; Jankovic, B; Karlovic, Z; Pavelic, B

    2003-12-01

    Reduction of cariogenic bacteria, especially salivary Streptococcus mutans and lactobacilli is a valuable clinical procedure that in many ways alleviates implementation of targeted caries preventive procedures in the entire population. The aim of this study was to investigate the caries preventive values of certain preventive procedures in in vivo conditions. Four groups of subjects, each with 18 children aged from 4-5 and 10-12 years (n = 72) were treated with different caries preventive agent (aminfluoride solution, Proxyt paste, chewing gum containing xylitol and fluoride and chlorhexidine solution). During a period of two months five control measurements for number of salivary Streptococcus mutans (SM) and lactobacilli (LB) were performed. At the end of the study the best result in the reduction of the bacteria was achieved by the application of Proxyt paste and daily use of chewing gum (p < 0.001). In patients treated with this preventive procedure the number of SM was reduced by 1 class and LB to < 10(4) CFU/ml saliva after two months of study. The results obtained indicate that professional teeth cleaning and use of chewing gum with xylitol and fluorides on daily basis can be very effective protocol for cariogenic bacteria reduction and in the individual caries prevention.

  14. Levansucrase and sucrose phoshorylase contribute to raffinose, stachyose, and verbascose metabolism by lactobacilli.

    PubMed

    Teixeira, Januana S; McNeill, Victoria; Gänzle, Michael G

    2012-09-01

    Raffinose family oligosaccharides (RFOs) in food are considered anti-nutritional factors. This study elucidated the role of α-galactosidase (α-Gal), levansucrase, and sucrose phosphorylase for conversion of RFOs by lactobacilli. Quantification of gene expression by reverse-transcriptase quantitative PCR revealed that expression of levansucrase and sucrose phosphorylase by Lactobacillus reuteri is increased more than 100 fold when sucrose or raffinose are available. Fava bean (Vicia faba) or field pea (Pisum sativum) flours were fermented with α-Gal positive L. reuteri or α-Gal negative Lactobacillus sanfranciscensis. Isogenic strains lacking levansucrase activity, a L. reuteri ftfA mutant and a L. sanfranciscensis levS mutant, were used for comparison. During growth in pulse flours, L. sanfranciscensis accumulated melibiose and α-galactooligosaccharides (α-GOSs); the levansucrase-negative strain did not grow. L. reuteri metabolized raffinose, stachyose, and verbascose by levansucrase activity and accumulated α-GOSs as metabolic intermediates. Oligosaccharide metabolism in the levansucrase-negative mutant was slower, and accumulation of α-GOSs was not observed. The use of sorghum sourdough fermented with L. reuteri LTH5448 and bean flour in gluten-free baking converted RFOs to α-GOSs by levansucrase and invertase activities. In conclusion, the elucidation of the role levansucrase in RFO metabolism by lactobacilli allowed the conversion or hydrolysis of RFOs in food fermentations.

  15. Diversity and dynamics of lactobacilli populations during ripening of RDO Camembert cheese.

    PubMed

    Henri-Dubernet, Ségolène; Desmasures, Nathalie; Guéguen, Micheline

    2008-03-01

    The diversity and dynamics of Lactobacillus populations in traditional raw milk Camembert cheese were monitored throughout the manufacturing process in 3 dairies. Culture-dependent analysis was carried out on isolates grown on acidified de Man - Rogosa - Sharpe agar and Lactobacillus anaerobic de Man Rogosa Sharpe agar supplemented with vancomycin and bromocresol green media. The isolates were identified by polymerase chain reaction - temperature gradient gel electrophoresis (PCR-TGGE) and (or) species-specific PCR and (or) sequencing, and Lactobacillus paracasei and Lactobacillus plantarum isolates were characterized by pulsed field gel electrophoresis (PFGE). Milk and cheese were subjected to culture-independent analysis by PCR-TGGE. Presumed lactobacilli were detected by plate counts throughout the ripening process. However, molecular analysis of total DNA and DNA of isolates failed to detect Lactobacillus spp. in certain cases. The dominant species in the 3 dairies was L. paracasei. PFGE analysis revealed 21 different profiles among 39 L. paracasei isolates. Lactobacillus plantarum was the second most isolated species, but it occurred nearly exclusively in one dairy. The other species isolated were Lactobacillus parabuchneri, Lactobacillus fermentum, Lactobacillus acidophilus, Lactobacillus helveticus, a Lactobacillus psittaci/delbrueckii subsp. bulgaricus/gallinarum/crispatus group, Lactobacillus rhamnosus, Lactobacillus delbrueckii subsp. bulgaricus, L. delbrueckii subsp. lactis, Lactobacillus brevis, Lactobacillus kefiri, and Lactobacillus perolens. Lactobacilli diversity at the strain level was high. Dynamics varied among dairies, and each cheese exhibited a specific picture of species and strains.

  16. Utilisation of steviol glycosides from Stevia rebaudiana (Bertoni) by lactobacilli and bifidobacteria in in vitro conditions.

    PubMed

    Kunová, Gabriela; Rada, Vojtěch; Vidaillac, Adrien; Lisova, Ivana

    2014-05-01

    In the current study, eight strains of bifidobacteria and seven strains of lactobacilli were tested for their ability to grow in the presence of rebaudioside A and steviol glycosides from the sweetener Natusweet M001 originating from herb Stevia rebaudiana (Bertoni). Stevia is gaining popularity as a natural, non-caloric sugar substitute, and recently, it was allowed as a food additive by European Union too. Utilisation of steviol glycosides by intestinal microbiota suggests that they might have potential prebiotic effect. Based on the evaluation of bacterial density and pH values in our in vitro study, it was found that lactobacilli and bifidobacteria tested were able to utilise steviol glycosides as a carbon source only to a very limited extent. All strains tested showed significantly lower change in the absorbance A540 (P < 0.05) and pH decrease of the growth media as compared with the positive controls (medium containing glucose as a carbon source and de Man Rogosa Sharpe broth). We concluded that a suggested prebiotic effect was not confirmed either in the case of rebaudioside A or in the case of the sweetener Natusweet M001 containing a mixture of steviol glycosides.

  17. Ureaplasma urealyticum and Mycoplasma hominis sensitivity to bacteriocins produced by two Lactobacilli strains.

    PubMed

    Daniele, M; Ruiz, F; Pascual, L; Barberis, L

    2011-10-01

    The purpose of the present study was to determine the inhibitory activities of two bacteriocins, produced by lactobacilli, against genital mycoplasmas. In this study, infections produced by genital mycoplasmas were studied; of these, 1.3% were caused by Mycoplasma hominis, 10.7% by Ureaplasma urealyticum and 5.6% by U. urealyticum + M. hominis. U. urealyticum was isolated from 75 out of 123 patients with genital mycoplasmas, while M. hominis was isolated from 9 patients (7.3%) and both U. urealyticum and M. hominis from 39 patients (31.7%). Bacteriocins, L23 and L60, produced by Lactobacillus fermentum and L. rhamnosus, respectively, appear to be two novel inhibitors of bacterial infection with potential antibacterial activity. Both bacteriocins proved to be active against 100% of strains tested; MICs of bacteriocin L23 ranged between 320 and 160 UA ml(-1) for 78% of the M. hominis strains and between 320 and 80 UA ml(-1) for 95% of the U. urealyticum strains. In addition, bacteriocin L60 was still active at 160 UA ml(-1) for a high percentage (56%) of M. hominis strains, and at 80 UA ml(-1) for 53% of the U. urealyticum strains. Interestingly, these antimicrobial substances produced by lactobacilli showed an inhibitory activity against genital mycoplasmas even when diluted. Altogether, our study indicates that the bacteriocins, L23 and L60, are good candidates for the treatment or prevention of genital infections in women.

  18. Yeast fermentation affected by homo- and hetero-fermentative Lactobacilli isolated from fuel ethanol distilleries with sugarcane products as substrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antagonism between by yeast and lactobacilli is largely dependent on the initial population of each organism. While homo-fermentative lactobacillus present higher inhibitory effect upon yeast when in equal cell number, in industrial fuel ethanol conditions where high yeast cell densities prevail...

  19. Differential targeting of the E-Cadherin/β-Catenin complex by gram-positive probiotic lactobacilli improves epithelial barrier function.

    PubMed

    Hummel, Stephanie; Veltman, Katharina; Cichon, Christoph; Sonnenborn, Ulrich; Schmidt, M Alexander

    2012-02-01

    The intestinal ecosystem is balanced by dynamic interactions between resident and incoming microbes, the gastrointestinal barrier, and the mucosal immune system. However, in the context of inflammatory bowel diseases (IBD), where the integrity of the gastrointestinal barrier is compromised, resident microbes contribute to the development and perpetuation of inflammation and disease. Probiotic bacteria have been shown to exert beneficial effects, e.g., enhancing epithelial barrier integrity. However, the mechanisms underlying these beneficial effects are only poorly understood. Here, we comparatively investigated the effects of four probiotic lactobacilli, namely, Lactobacillus acidophilus, L. fermentum, L. gasseri, and L. rhamnosus, in a T84 cell epithelial barrier model. Results of DNA microarray experiments indicating that lactobacilli modulate the regulation of genes encoding in particular adherence junction proteins such as E-cadherin and β-catenin were confirmed by quantitative reverse transcription-PCR (qRT-PCR). Furthermore, we show that epithelial barrier function is modulated by Gram-positive probiotic lactobacilli via their effect on adherence junction protein expression and complex formation. In addition, incubation with lactobacilli differentially influences the phosphorylation of adherence junction proteins and the abundance of protein kinase C (PKC) isoforms such as PKCδ that thereby positively modulates epithelial barrier function. Further insight into the underlying molecular mechanisms triggered by these probiotics might also foster the development of novel strategies for the treatment of gastrointestinal diseases (e.g., IBD).

  20. Nutritionally enhanced fermented sausages as a vehicle for potential probiotic lactobacilli delivery.

    PubMed

    Rubio, Raquel; Jofré, Anna; Aymerich, Teresa; Guàrdia, Maria Dolors; Garriga, Margarita

    2014-02-01

    The suitability of three potential probiotic lactobacilli strains (Lactobacillus casei CTC1677, L. casei CTC1678 and Lactobacillus rhamnosus CTC1679), previously isolated from infants' faeces and characterized, and three commercial probiotic strains (Lactobacillus plantarum 299v, L. rhamnosus GG and L. casei Shirota) was assessed during the manufacture of low-acid fermented sausages (fuets) with reduced Na(+) and fat content. The inoculated strains were successfully monitored by RAPD-PCR during the process. L. rhamnosus CTC1679 was the only strain able to grow and dominate (levels ca. 10(8)CFU/g) the endogenous lactic acid bacteria population in two independent trials, throughout the ripening process. Thus, fuet containing L. rhamnosus CTC1679 as a starter culture could be a suitable vehicle for putative probiotic bacteria delivery. All the final products recorded a satisfactory overall sensory quality without any noticeable off-flavour, and with the characteristic sensory properties of low-acid fermented sausages.

  1. Detection, growth, and amine-producing capacity of lactobacilli in cheese.

    PubMed

    Joosten, H M; Northolt, M D

    1989-09-01

    A differential plating medium was developed to detect decarboxylating lactobacilli in cheese. With this medium, 15 cheeses made from raw milk were investigated for the presence of these bacteria. Five histidine-decarboxylating strains and one tyrosine-decarboxylating strain were isolated. The isolates were identified with the API 50L system. Accordingly, each of the five histidine-decarboxylating strains was identified as Lactobacillus buchneri, whereas the tyrosine-decarboxylating strain is a representative of Lactobacillus brevis. Cheesemaking experiments using a low inoculum concentration of the histidinedecarboxylating L. buchneri strain St2A (0.2 CFU/ml of milk) showed that, under conditions of accelerated proteolysis, histamine may accumulate rapidly; after 3 months of ripening, 410 mg/kg was found. An inoculum concentration of 5 CFU/ml gave rise to the formation of 1,060 mg/kg.

  2. Effect of Pomegranate Juice on Dental Plaque Microorganisms (Streptococci and Lactobacilli)

    PubMed Central

    Kote, Sowmya; Kote, Sunder; Nagesh, Lakshminarayan

    2011-01-01

    To study the effect of pomegranate juice on dental plaque microorganisms. A clinical trial was conducted on thirty healthy volunteers aged 25-30 years who visited Out Patient Department (OPD) of Bapuji Dental College and Hospital, Davangere during the month of October 2006. Before conducting the study, thorough oral prophylaxis was done and the subjects were asked to refrain from the oral hygiene procedures for 24 hrs. Dental plaque was collected from each subject, before and after rinsing 30ml of pomegranate juice without sugar. Plaque samples were cultured using Mitis Salivarius Agar and Rogosa SL Agar media. Wilcoxon's signed rank test was used for statistical analysis. Results showed that pomegranate rinse was effective against dental plaque microorganisms. There was a significant reduction in the number of colony forming units of streptococci (23%) and lactobacilli (46%). The ruby red seeds may be a possible alternative for the treatment of dental plaque bacteria. PMID:23284205

  3. Identification and evaluation of the probiotic potential of lactobacilli isolated from canine milk.

    PubMed

    Martín, Rocío; Olivares, Mónica; Pérez, Manuela; Xaus, Jordi; Torre, Celina; Fernández, Leonides; Rodríguez, Juan M

    2010-08-01

    Canine milk protects puppies against infectious diseases through a variety of mechanisms. In this study, the presence of potentially probiotic lactic acid bacteria grown on MRS-Cys agar plates from milk of nine bitches was investigated. The Gram positive catalase negative bacilli identified in this study belonged to four Lactobacillus species (Lactobacillus reuteri, Lactobacillus fermentum, Lactobacillus murinus, Lactobacillus animalis), as well as one isolate that was identified as Weissella viridescens. Random amplified polymorphic DNA profiling revealed 28 different genetic profiles among the lactobacilli isolates. Their probiotic potential was evaluated through different assays, including survival in conditions that resemble those existing in the gastrointestinal tract, production of antimicrobial compounds, adherence to intestinal mucin, degradation of mucin and pattern of antibiotic sensitivity. Some strains showed potential for future applications as canine probiotics.

  4. Probiotic lactobacilli: an innovative tool to correct the malabsorption syndrome of vegetarians?

    PubMed

    Famularo, Giuseppe; De Simone, Claudio; Pandey, Vandana; Sahu, Adita Ranjan; Minisola, Giovanni

    2005-01-01

    Vegetarians may have subtle nutritional deficiencies which have been related to the occurrence of an unrecognized malabsorption syndrome. The excess phytate content in cereals, nuts, legumes and oilseeds which represent the mainstay of their food intake, seems to play a central role in the pathogenesis of this malabsorption syndrome as an inverse relationship has been shown to link the phytate content of the diet with the intestinal absorption of trace minerals and proteins. We postulate that manipulating the endogenous digestive microflora of subjects on a vegetarian diet through administering probiotic lactic bacteria would represent an innovative tool to counteract the occurrence of the malabsorption syndrome dependent on the high phytate content of their diet. Even though there are no data about the composition of endogenous digestive microflora in subjects on a vegetarian diet, we expect that probiotic lactobacilli can interact with or affect distinct yet interrelated components within the intestinal milieu, such as epithelial cells, enteric flora, and/or mucosal immune cells. This would ultimately translate into the correction of the unregulated mechanisms implicated in the altered intestinal absorption of trace metals and proteins commonly seen in vegetarians. Clinical experience with probiotic therapy of patients with inflammatory bowel disease fully agrees with this view. One additional point of interest is that probiotic lactobacilli, and other species of the endogenous digestive microflora as well, are an important source of the enzyme phytase which catalyses the release of phosphate from phytate and hydrolyses the complexes formed by phytate and metal ions or other cations, rendering them more soluble ultimately improving and facilitating their intestinal absorption. The regular intake of probiotic preparation, may represent a cheap and safe tool in order to convert a diet with a low potential for bioavailability of trace minerals and proteins, such as

  5. Diarrhea-associated pathogens, lactobacilli and cellulolytic bacteria in equine feces: responses to antibiotic challenge.

    PubMed

    Harlow, Brittany E; Lawrence, Laurie M; Flythe, Michael D

    2013-09-27

    Antibiotics are important to equine medicine, but antibiotic-associated diarrhea (AAD) can lead to poor performance and even mortality. AAD is attributed to disruption of the hindgut microbiota, which permits proliferation of pathogenic microbes. The goal of this study was to evaluate the effects of common antibiotics on cellulolytic bacteria, lactobacilli, and AAD-associated pathogens in the feces of healthy horses. Fifteen horses were assigned to three treatment groups (blocked by age and sex): control (no antibiotics), trimethoprim-sulfadiazine (PO), or ceftiofur (IM). Fecal samples (n=8 per horse) were taken during dietary adaptation (3 weeks), antibiotic challenge (1 week), and withdrawal (1 week). Bacteria were enumerated by serial dilution and viable count. Cellulolytic bacteria decreased by >99% during administration of either antibiotic (P<0.0001) and were still less than controls at the end of the withdrawal period (P<0.0001). Fecal samples from horses challenged with ceftiofur had 75% fewer lactobacilli than those from control horses at the end of the antibiotic challenge period (P<0.05). Antibiotic challenged horses also shed more salmonella than control horses (P<0.05). Antibiotics had no effect on the number of Clostridium perfringens isolates. There was no detectable Clostridium difficile during adaptation or in any control horse. C. difficile increased (P<0.0001) to approximately 10(4)cfu/g when horses were challenged with antibiotics, and were still detectable 1 week after withdrawal. These results indicate that antibiotics can disrupt the normal gastrointestinal microbiota and allow proliferation of Salmonella spp. and C. difficile.

  6. Technological and probiotic role of adjunct cultures of non-starter lactobacilli in soft cheeses.

    PubMed

    Burns, Patricia; Cuffia, Facundo; Milesi, Mercedes; Vinderola, Gabriel; Meinardi, Carlos; Sabbag, Nora; Hynes, Erica

    2012-05-01

    The influence of two cheese-isolated Lactobacillus strains on cheese composition, acceptability and probiotic capacity was assessed. Soft cheeses with and without the addition of Lactobacillus plantarum I91 or Lactobacillus paracasei I90 were prepared. Gross composition was assessed and secondary proteolysis was described by soluble fractions and free amino acids profiles. Acceptability was determined by a panel of 98 non-trained consumers. Cheeses harboring added Lactobacillus strains were also studied in vivo to evaluate their probiotic capacity. Gross composition of the cheeses was similar for control and treated (Lactobacillus-added) cheeses. Peptidolysis increased in cheeses with added lactobacilli, which was evidenced by a higher free amino acid content. Overall, the acceptability of the cheeses was good: 65%-80% of the consumers said that they "liked very much" or "liked" the cheeses. Cheeses with L. plantarum I91 showed the highest changes in composition and proteolysis and were the most accepted ones. On the contrary, composition of cheeses with L. paracasei I90 was similar to that of the controls, but these samples were less accepted than cheeses without lactobacilli. The oral administration of cheese containing L. plantarum I91 or L. paracasei I90 proved to be safe and able to enhance the number of IgA + cells in the small intestine lamina propria of mice. The use of selected strains of NSLAB exerted a technological and probiotic role: it contributed to the standardization of cheese quality and induced benefic health effects at the gut mucosa in vivo.

  7. Hydrogen-peroxide producing lactobacilli are associated with lower levels of vaginal IL1β, independent of bacterial vaginosis

    PubMed Central

    Mitchell, Caroline; Fredricks, David; Agnew, Kathy; Hitti, Jane

    2015-01-01

    Background The presence of hydrogen peroxide (H2O2)-producing lactobacilli in the vagina is associated with decreased rates of preterm birth and HIV acquisition. We hypothesize that this is due to immunomodulatory effects of these species. Methods Concentrations of IL1β, IL6, IL8, secretory leukocyte protease inhibitor (SLPI) and human beta defensin 2 (HBD2) were quantified from vaginal swabs from 4 groups of women: women with and without bacterial vaginosis (BV) by Nugent score, further stratified by detection of H2O2-producing lactobacilli by semi-quantitative culture. Ten quantitative PCR assays characterized presence and quantity of select Lactobacillus and BV-associated species in each group. Levels of immune markers and bacteria were compared between the four groups using ANOVA, Kruskal-Wallis, Mann Whitney U or chi-square tests. Results Swabs from 110 women from four groups were included: 26 had a normal Nugent score (BV−), and no H2O2-producing lactobacilli detected(H2O2−), 47 were BV−, H2O2+, 27 BV+, H2O2− and 10 BV+, H2O2+. The groups were similar in age, marital status and reproductive history, but not ethnicity: the BV−, H2O2− group had more Caucasian participants(p = 0.02). In women with and without BV, IL1β was lower in the H2O2+ groups. HBD2 was lowest in BV+ H2O2− women and highest in BV−, H2O2−. SLPI was lower in women with BV, and did not differ by the presence of H2O2–producing lactobacilli. In regression analysis higher quantities of L. crispatus were associated with lower quantities of IL1β. Detection and quantity of BV-associated species by qPCR was significantly different between women with and without BV, but not between women with and without H2O2-producing lactobacilli within those groups. Conclusions The presence of H2O2-producing lactobacilli is associated with lower levels of some vaginal pro-inflammatory cytokines, even in women with BV. PMID:26222747

  8. Comparison of Microbiological and Probiotic Characteristics of Lactobacilli Isolates from Dairy Food Products and Animal Rumen Contents

    PubMed Central

    Jose, Neethu Maria; Bunt, Craig R.; Hussain, Malik Altaf

    2015-01-01

    Lactobacilli are employed in probiotic food preparations and as feed additives in poultry and livestock, due to health benefits associated with their consumption. The objective of this study was to evaluate and compare the probiotic potential of ten lactobacilli strains isolated from commercial dairy food products and animal rumen contents in New Zealand. Genetic identification of the isolates revealed that all belonged to the genus Lactobacillus, specifically the species L. reuteri, L. rhamnosus and L. plantarum. All isolates did not show any haemolytic behaviour. Isolates of dairy origin showed better tolerance to low pH stress. On the other hand, rumen isolates exhibited a higher tolerance to presence of bile salts. All isolates exhibited resistance to aminoglycoside antibiotics, however most were sensitive to ampicillin. Isolates of rumen origin demonstrated a higher inhibitory effect on Listeria monocytogenes, Enterobacter aerogenes and Salmonella menston. Bacterial adherence of all isolates increased with a decrease in pH. This screening study on lactobacilli isolates has assessed and identified potential probiotic candidates for further evaluation. PMID:27682086

  9. Comparison of Microbiological and Probiotic Characteristics of Lactobacilli Isolates from Dairy Food Products and Animal Rumen Contents.

    PubMed

    Jose, Neethu Maria; Bunt, Craig R; Hussain, Malik Altaf

    2015-04-15

    Lactobacilli are employed in probiotic food preparations and as feed additives in poultry and livestock, due to health benefits associated with their consumption. The objective of this study was to evaluate and compare the probiotic potential of ten lactobacilli strains isolated from commercial dairy food products and animal rumen contents in New Zealand. Genetic identification of the isolates revealed that all belonged to the genus Lactobacillus, specifically the species L. reuteri, L. rhamnosus and L. plantarum. All isolates did not show any haemolytic behaviour. Isolates of dairy origin showed better tolerance to low pH stress. On the other hand, rumen isolates exhibited a higher tolerance to presence of bile salts. All isolates exhibited resistance to aminoglycoside antibiotics, however most were sensitive to ampicillin. Isolates of rumen origin demonstrated a higher inhibitory effect on Listeria monocytogenes, Enterobacter aerogenes and Salmonella menston. Bacterial adherence of all isolates increased with a decrease in pH. This screening study on lactobacilli isolates has assessed and identified potential probiotic candidates for further evaluation.

  10. Effect of mesophilic lactobacilli and enterococci adjunct cultures on the final characteristics of a microfiltered milk Swiss-type cheese.

    PubMed

    Bouton, Yvette; Buchin, Solange; Duboz, Gabriel; Pochet, Sylvie; Beuvier, Eric

    2009-04-01

    The effect of four associations of adjunct cultures composed of mesophilic lactobacilli and enterococci, either solely or combined, on the microbiological, biochemical and sensory characteristics of Swiss-type cheese made using microfiltered cows' milk and supplemented with propionibacteria was studied. The global pattern of growth was similar to that generally observed in raw milk cheese and interactions between microflora were highlighted during ripening. Enterococci, which negatively affected the survival of streptococci starters, seemed to play a limited role in the formation of volatile compounds, probably due to their low levels throughout ripening. On the contrary, mesophilic lactobacilli, which affected the evolution of propionibacteria, enterococci and L. delbrueckii subsp. lactis starter counts, modified free amino acid content, production of volatile compounds and organoleptic properties of mature cheese. This population appeared to be of major importance in the formation of cheese flavor as it was positively related to numerous potential flavor compounds such as alcohols and their corresponding esters, acetaldehyde and 4-methyl-4-heptanone. The original mesophilic lactobacilli present in milk could play an important role in the sensorial diversity of raw milk Swiss-type cheeses such as Comte.

  11. Comparative Functional Genomics of Lactobacillus spp. Reveals Possible Mechanisms for Specialization of Vaginal Lactobacilli to Their Environment

    PubMed Central

    Suzuki, Haruo; Hickey, Roxana J.; Forney, Larry J.

    2014-01-01

    Lactobacilli are found in a wide variety of habitats. Four species, Lactobacillus crispatus, L. gasseri, L. iners, and L. jensenii, are common and abundant in the human vagina and absent from other habitats. These may be adapted to the vagina and possess characteristics enabling them to thrive in that environment. Furthermore, stable codominance of multiple Lactobacillus species in a single community is infrequently observed. Thus, it is possible that individual vaginal Lactobacillus species possess unique characteristics that confer to them host-specific competitive advantages. We performed comparative functional genomic analyses of representatives of 25 species of Lactobacillus, searching for habitat-specific traits in the genomes of the vaginal lactobacilli. We found that the genomes of the vaginal species were significantly smaller and had significantly lower GC content than those of the nonvaginal species. No protein families were found to be specific to the vaginal species analyzed, but some were either over- or underrepresented relative to nonvaginal species. We also found that within the vaginal species, each genome coded for species-specific protein families. Our results suggest that even though the vaginal species show no general signatures of adaptation to the vaginal environment, each species has specific and perhaps unique ways of interacting with its environment, be it the host or other microbes in the community. These findings will serve as a foundation for further exploring the role of lactobacilli in the ecological dynamics of vaginal microbial communities and their ultimate impact on host health. PMID:24488312

  12. Molecular Detection of Two Potential Probiotic Lactobacilli Strains and Evaluation of Their Performance as Starter Adjuncts in Yogurt Production

    PubMed Central

    Saxami, Georgia; Papadopoulou, Olga S.; Chorianopoulos, Nikos; Kourkoutas, Yiannis; Tassou, Chrysoula C.; Galanis, Alex

    2016-01-01

    A molecular method for efficient and accurate detection and identification of two potential probiotic lactobacilli strains isolated from fermented olives, namely Lactobacillus pentosus B281 and Lb. plantarum B282, was developed in the present study. Random Amplified Polymorphic DNA (RAPD) analysis was performed, and strain specific primers were designed and applied in a multiplex polymerase chain reaction (PCR) assay. The specificity of the assay was tested and successfully confirmed in 27 and 22 lactobacilli strains for Lb. pentosus B281 and Lb. plantarum B282, respectively. Moreover, the two strains were used as starter cultures in yogurt production. Cell enumeration followed by multiplex PCR analysis demonstrated that the two strains were present in yogurt samples at levels ≥6 log CFU/g even after 35 days of storage at 4 °C. Microbiological analysis showed that lactobacilli and streptococci were present within usual levels, whereas enterobacteriaceae and yeast/mold counts were not detected as expected. Although the pH values of the novel products were slightly lower than the control ones, the yogurt containing the probiotic cultures scored similar values compared to the control in a series of sensory tests. Overall, these results demonstrated the possible use of the two strains as starter adjuncts in the production of yogurt with potential probiotic properties. PMID:27153065

  13. Comparative functional genomics of Lactobacillus spp. reveals possible mechanisms for specialization of vaginal lactobacilli to their environment.

    PubMed

    Mendes-Soares, Helena; Suzuki, Haruo; Hickey, Roxana J; Forney, Larry J

    2014-04-01

    Lactobacilli are found in a wide variety of habitats. Four species, Lactobacillus crispatus, L. gasseri, L. iners, and L. jensenii, are common and abundant in the human vagina and absent from other habitats. These may be adapted to the vagina and possess characteristics enabling them to thrive in that environment. Furthermore, stable codominance of multiple Lactobacillus species in a single community is infrequently observed. Thus, it is possible that individual vaginal Lactobacillus species possess unique characteristics that confer to them host-specific competitive advantages. We performed comparative functional genomic analyses of representatives of 25 species of Lactobacillus, searching for habitat-specific traits in the genomes of the vaginal lactobacilli. We found that the genomes of the vaginal species were significantly smaller and had significantly lower GC content than those of the nonvaginal species. No protein families were found to be specific to the vaginal species analyzed, but some were either over- or underrepresented relative to nonvaginal species. We also found that within the vaginal species, each genome coded for species-specific protein families. Our results suggest that even though the vaginal species show no general signatures of adaptation to the vaginal environment, each species has specific and perhaps unique ways of interacting with its environment, be it the host or other microbes in the community. These findings will serve as a foundation for further exploring the role of lactobacilli in the ecological dynamics of vaginal microbial communities and their ultimate impact on host health.

  14. Molecular Detection of Two Potential Probiotic Lactobacilli Strains and Evaluation of Their Performance as Starter Adjuncts in Yogurt Production.

    PubMed

    Saxami, Georgia; Papadopoulou, Olga S; Chorianopoulos, Nikos; Kourkoutas, Yiannis; Tassou, Chrysoula C; Galanis, Alex

    2016-05-04

    A molecular method for efficient and accurate detection and identification of two potential probiotic lactobacilli strains isolated from fermented olives, namely Lactobacillus pentosus B281 and Lb. plantarum B282, was developed in the present study. Random Amplified Polymorphic DNA (RAPD) analysis was performed, and strain specific primers were designed and applied in a multiplex polymerase chain reaction (PCR) assay. The specificity of the assay was tested and successfully confirmed in 27 and 22 lactobacilli strains for Lb. pentosus B281 and Lb. plantarum B282, respectively. Moreover, the two strains were used as starter cultures in yogurt production. Cell enumeration followed by multiplex PCR analysis demonstrated that the two strains were present in yogurt samples at levels ≥6 log CFU/g even after 35 days of storage at 4 °C. Microbiological analysis showed that lactobacilli and streptococci were present within usual levels, whereas enterobacteriaceae and yeast/mold counts were not detected as expected. Although the pH values of the novel products were slightly lower than the control ones, the yogurt containing the probiotic cultures scored similar values compared to the control in a series of sensory tests. Overall, these results demonstrated the possible use of the two strains as starter adjuncts in the production of yogurt with potential probiotic properties.

  15. Antagonistic activity of probiotic lactobacilli against human enteropathogenic bacteria in homemade tvorog curd cheese from Azerbaijan

    PubMed Central

    Masoumikia, Reza; Ganbarov, Khudaverdi

    2015-01-01

    Introduction: Human health is deemed to be maintained by the crosstalk among the body and probiotic bacteria. Disruptions in this composition are associated with the pathogenesis of numerous diseases. Through modernization, traditional foods consumption has been abandoned and native food starters have been substituted with industrial products. Hence, we aimed to isolate and evaluate probiotic bacteria from traditional fermented foods which can be used as probiotics as well as starter cultures in food industry and in medicine against antibiotic resistant pathogenes. To this end, an intact village was recognized in the Republic of Azerbaijan with traditional dairy products, yielding a variety of potential probiotics. Methods: In this study, tvorog as a traditional dairy product from Dashkasan, Ismailli and khachmaz regions in Azerbaijan was characterized for the isolation of Lactobacilli with probiotic potentiality. The bacteria were tested for the resistance to the acid, bile, and the antagonistic effect of human pathogenic bacteria. The isolates were identified by 16s rDNA sequencing with a blast to the databank. Results: Three species with higher homology to the L. planetarium, L. rhamnosus, and L. casei with high probiotic potentiality and antibacterial effects were isolated. Conclusion: Homemade tvorog curd cheese in Azerbaijan harbor a variety of probiotics with industrial applications as well as potentiality to be preserved in a biobank for the future medicinal applications especially against antibiotic resistant pathogenes. PMID:26457253

  16. Heterologous Protein Secretion in Lactobacilli with Modified pSIP Vectors

    PubMed Central

    Karlskås, Ingrid Lea; Maudal, Kristina; Axelsson, Lars; Rud, Ida; Eijsink, Vincent G. H.; Mathiesen, Geir

    2014-01-01

    We describe new variants of the modular pSIP-vectors for inducible gene expression and protein secretion in lactobacilli. The basic functionality of the pSIP system was tested in Lactobacillus strains representing 14 species using pSIP411, which harbors the broad-host-range Lactococcus lactis SH71rep replicon and a β-glucuronidase encoding reporter gene. In 10 species, the inducible gene expression system was functional. Based on these results, three pSIP vectors with different signal peptides were modified by replacing their narrow-host-range L. plantarum 256rep replicon with SH71rep and transformed into strains of five different species of Lactobacillus. All recombinant strains secreted the target protein NucA, albeit with varying production levels and secretion efficiencies. The Lp_3050 derived signal peptide generally resulted in the highest levels of secreted NucA. These modified pSIP vectors are useful tools for engineering a wide variety of Lactobacillus species. PMID:24614815

  17. Sweet potatoes as a basic component in developing a medium for the cultivation of lactobacilli.

    PubMed

    Hayek, Saeed A; Shahbazi, Aboghasem; Awaisheh, Saddam S; Shah, Nagendra P; Ibrahim, Salam A

    2013-01-01

    A sweet potato medium (SPM) was formed with extract from baked sweet potatoes supplemented with 0, 4, or 8 g/L of each nitrogen source (beef extract, yeast extract, and proteose peptone #3) to form SPM1, SPM2, and SPM3 respectively. Lactobacilli MRS was used as control medium. Ten Lactobacillus strains containing an average of 2.34 ± 0.29 log CFU/mL were inoculated individually into batches of MRS, SPM1, SPM2, and SPM3. The growth patterns for the tested Lactobacillus strains growing in SPM2 and SPM3 were found to be similar to that in MRS. The average final population after 24 h of incubation in MRS, SPM2, and SPM3 reached 10.41 ± 0.35, 10.59 ± 0.27, and 10.72 ± 0.19 log CFU/mL respectively. SPM2 and SPM3 maintained higher pH values throughout the incubation period than MRS. These findings indicate that SPM2 can be a suitable medium for the growth of Lactobacillus and can provide an alternative at low-cost.

  18. Radiation resistance of lactobacilli isolated from radurized meat relative to growth and environment.

    PubMed Central

    Hastings, J W; Holzapfel, W H; Niemand, J G

    1986-01-01

    Of 113 lactobacilli isolated from radurized (5 kGy) minced meat, 7 Lactobacillus sake strains, 1 L. curvatus strain, and 1 L. farciminis strain were used for radiation resistance studies in a semisynthetic substrate (i.e., modified MRS broth). Five reference Lactobacillus spp., one Staphylococcus aureus strain, and one Salmonella typhimurium strain were used for comparative purposes. All L. sake isolates exhibited the phenomenon of being more resistant to gamma-irradiation in the exponential (log) phase than in the stationary phase of their growth cycles by a factor of 28%. Four references strains also exhibited this phenomenon, with L. sake (DSM 20017) showing a 68% increase in resistance in the log phase over the stationary phase. This phenomenon was not common to all bacteria tested and is not common to all strains with high radiation resistance. Four L. sake isolates and three reference strains were used in radiation sensitivity testing in a natural food system (i.e., meat). The bacteria were irradiated in minced meat and packaged under four different conditions (air, vacuum, CO2, and N2). Organisms exhibited the highest death rate (lowest D10 values [doses required to reduce the logarithm of the bacterial population by 1] ) under CO2 packaging conditions, but resistance to irradiation was increased under N2. The D10 values of the isolates were generally greater than those of the reference strains. The D10 values were also higher (approximately two times) in meat than in semisynthetic growth medium. PMID:3096207

  19. Effect of traditional leafy vegetables on the growth of lactobacilli and bifidobacteria.

    PubMed

    Kassim, Muhammad Arshad; Baijnath, Himansu; Odhav, Bharti

    2014-12-01

    Traditional leafy vegetables, apart from being a staple in the diet of most of sub-Saharan Africa, are an essential part of traditional medicine and are used daily by traditional healers in the region to treat a wide variety of ailments. In this study, a batch culture technique was used to investigate whether 25 infusions from 22 traditional leafy vegetables stimulated the growth of Lactobacillus bulgaricus, Lactobacillus lactis, Lactobacillus reuteri and Bifidobacterium longum in pure culture. High performance liquid chromatography was used to determine the inulin content of the infusions. Sonchus oleraceus stimulated all four strains and Taraxacum officinale stimulated three strains. In total, 18 plants stimulated at least one of the four probiotic strains. The inulin content of the infusions varied between 2.5% and 3.6%, with Asparagus sprengeri containing the highest percentage. These results indicate that traditional leafy vegetables do stimulate the growth of the selected lactobacilli and bifidobacteria in pure culture and contain inulin. These infusions can now be tested for prebiotic potential using mixed culture systems or human hosts.

  20. Comparison of innate immune activation after prolonged feeding of milk fermented with three species of Lactobacilli.

    PubMed

    Kapila, Rajeev; Sebastian, Renjith; Varma D, Vivek Phani; Sharma, Rohit; Kapasiya, Meena; Salingati, Vamshi; Kapila, Suman; Dang, Ajay K

    2013-11-01

    The present investigation aimed at identifying the abilities of three different species of probiotic lactobacilli to modulate cellular immune responses in mouse neutrophils and macrophages in vivo over a study period of 60 days. Neutrophil respiratory burst enzymes (cytochrome c reductase and MPO) showed remarkable increased activity (P ≤ 0.01) after consumption of milks fermented by different species of probiotics over 30 and 60 days of feeding trials. Enzyme activities (β-galactosidase and β-glucuronidase) and nitric oxide production also increased considerably (P ≤ 0.01) in macrophages, both in peritoneal fluid and in enriched cell cultures. The effects of enhanced enzyme activities were corroborated by simultaneous increases in the phagocytic activities of neutrophils and macrophages. The increases in cellular functions were invariably maximal during the first 30 days of study and were maintained, but did not increase, over the next 30 days. Further, Lactobacillus helveticus-fed groups were most effective at modulating neutrophil functions whereas Lactobacillus paracasei-fed groups were more potent at enhancing macrophage functions. Together, our results indicate that probiotics have strain specific effects on stimulating cellular functions while not causing excessive stimulation of the immune system over longer feeding periods, thereby resulting in maximum and stable health benefits.

  1. Evidence for the presence of heat-stable protein (HPr) and ATP-dependent HPr kinase in heterofermentative lactobacilli lacking phosphoenolpyruvate:glycose phosphotransferase activity.

    PubMed Central

    Reizer, J; Peterkofsky, A; Romano, A H

    1988-01-01

    An analysis of the biochemical basis for the lack of phosphoenolpyruvate:glycose phosphotransferase activity in heterofermentative lactobacilli was carried out. Extracts of Lactobacillus brevis and Lactobacillus buchneri failed to reconstitute phosphotransferase activity of extracts of Staphylococcus aureus mutants impaired in the phosphotransferase system due to the absence of enzyme I, enzyme IILac, or enzyme IIILac activity, suggesting that these lactobacilli lack those phosphotransferase system components. In contrast, complementation tests with an extract of a S. aureus mutant deficient in heat-stable protein (HPr) indicated the presence of HPr activity in heterofermentative lactobacilli. The HPr of L. brevis was purified and shown to have properties similar to those of a typical HPr. In addition, L. brevis possesses an ATP-dependent protein kinase that phosphorylates a serine residue of the endogenous HPr as well as other HPrs of Gram-positive origin. The kinase activity is markedly stimulated by phosphorylated compounds related to sugar metabolism and is negatively modulated by orthophosphate, pyrophosphate, or arsenate and by a low molecular weight endogenous factor. In keeping with the idea of a regulatory role for the phosphorylation of HPr in lactobacilli, a HPr[Ser(P)] phosphatase activity in L. brevis was also demonstrated. On the basis of the finding of HPr and a system for its reversible covalent modification in an organism devoid of a functional phosphotransferase system we propose that, in lactobacilli, HPr has a role in the regulation of pathways other than the phosphotransferase system. Images PMID:2832843

  2. DETECTION OF LACTOBACILLI IN MONTHLY MAIL-IN STOOL SAMPLES FROM 3-18 MONTHS OLD INFANTS AT GENETIC RISK FOR TYPE 1 DIABETES

    PubMed Central

    Salami, F; Abels, M; Hyöty, H; Vaziri-Sani, F; Aronsson, CA; Vehik, K; Delli, A; Hagopian, WA; Rewers, M; Ziegler, AG; Simell, O; Akolkar, B; Krischer, J; She, J; Lernmark, Å

    2014-01-01

    The feasibility to detect lactobacilli in mail-in infant stools collected monthly from 3-18 months old children was investigated. The aim was to determine total lactobacilli and Lactobacillus plantarum (L. plantarum) content (ng/g feces) in 50 infants each from Colorado (648 samples), Finland (624 samples) and Sweden (685 samples) who participated in the TEDDY (The Environmental Determinants of Diabetes in the Young) study. Total lactobacilli content varied markedly between 5 and 16,800 ng/g feces in the three clinical sites within and between individuals especially in infants. L.plantarum also varied markedly intra- and inter-individually from <0.5 - 736 ng/g feces. A higher variability of total lactobacilli was found before 10 months of age than after in the three different clinical sites. Sweden had the lowest total lactobacilli content compared to Colorado and Finland while the L.plantarum content was higher in Sweden. Mail-in stool samples from infants should prove useful in analyzing probiotics in childhood. PMID:25045339

  3. Characterization of Pro-Inflammatory Flagellin Proteins Produced by Lactobacillus ruminis and Related Motile Lactobacilli

    PubMed Central

    Neville, B. Anne; Forde, Brian M.; Claesson, Marcus J.; Darby, Trevor; Coghlan, Avril; Nally, Kenneth; Ross, R. Paul; O’Toole, Paul W.

    2012-01-01

    Lactobacillus ruminis is one of at least twelve motile but poorly characterized species found in the genus Lactobacillus. Of these, only L. ruminis has been isolated from mammals, and this species may be considered as an autochthonous member of the gastrointestinal microbiota of humans, pigs and cows. Nine L. ruminis strains were investigated here to elucidate the biochemistry and genetics of Lactobacillus motility. Six strains isolated from humans were non-motile while three bovine isolates were motile. A complete set of flagellum biogenesis genes was annotated in the sequenced genomes of two strains, ATCC25644 (human isolate) and ATCC27782 (bovine isolate), but only the latter strain produced flagella. Comparison of the L. ruminis and L. mali DSM20444T motility loci showed that their genetic content and gene-order were broadly similar, although the L. mali motility locus was interrupted by an 11.8 Kb region encoding rhamnose utilization genes that is absent from the L. ruminis motility locus. Phylogenetic analysis of 39 motile bacteria indicated that Lactobacillus motility genes were most closely related to those of motile carnobacteria and enterococci. Transcriptome analysis revealed that motility genes were transcribed at a significantly higher level in motile L. ruminis ATCC27782 than in non-motile ATCC25644. Flagellin proteins were isolated from L. ruminis ATCC27782 and from three other Lactobacillus species, while recombinant flagellin of aflagellate L. ruminis ATCC25644 was expressed and purified from E. coli. These native and recombinant Lactobacillus flagellins, and also flagellate L. ruminis cells, triggered interleukin-8 production in cultured human intestinal epithelial cells in a manner suppressed by short interfering RNA directed against Toll-Like Receptor 5. This study provides genetic, transcriptomic, phylogenetic and immunological insights into the trait of flagellum-mediated motility in the lactobacilli. PMID:22808200

  4. Growth kinetic models of five species of Lactobacilli and lactose consumption in batch submerged culture.

    PubMed

    Rezvani, Fazlollah; Ardestani, Fatemeh; Najafpour, Ghasem

    Kinetic behaviors of five Lactobacillus strains were investigated with Contois and Exponential models. Awareness of kinetic behavior of microorganisms is essential for their industrial process design and scale up. The consistency of experimental data was evaluated using Excel software. L. bulgaricus was introduced as the most efficient strain with the highest biomass and lactic acid yield of 0.119 and 0.602gg(-1) consumed lactose, respectively. The biomass and carbohydrate yield of L. fermentum and L. lactis were slightly less and close to L. bulgaricus. Biomass and lactic acid production yield of 0.117 and 0.358 for L. fermentum and 0.114 and 0.437gg(-1) for L.actobacillus lactis were obtained. L. casei and L. delbrueckii had the less biomass yield, nearly 11.8 and 22.7% less than L. bulgaricus, respectively. L. bulgaricus (R(2)=0.9500 and 0.9156) and L. casei (R(2)=0.9552 and 0.8401) showed acceptable consistency with both models. The investigation revealed that the above mentioned models are not suitable to describe the kinetic behavior of L. fermentum (R(2)=0.9367 and 0.6991), L. delbrueckii (R(2)=0.9493 and 0.7724) and L. lactis (R(2)=0.8730 and 0.6451). Contois rate equation is a suitable model to describe the kinetic of Lactobacilli. Specific cell growth rate for L. bulgaricus, L. casei, L. fermentum, L. delbrueckii and L. lactis with Contois model in order 3.2, 3.9, 67.6, 10.4 and 9.8-fold of Exponential model.

  5. Antimicrobial and antibiofilm potential of biosurfactants isolated from lactobacilli against multi-drug-resistant pathogens

    PubMed Central

    2014-01-01

    Background Biosurfactants (BS) are amphiphilic compounds produced by microbes, either on the cell surface or secreted extracellularly. BS exhibit strong antimicrobial and anti-adhesive properties, making them good candidates for applications used to combat infections. In this study, our goal was to assess the in vitro antimicrobial, anti-adhesive and anti-biofilm abilities of BS produced by Lactobacillus jensenii and Lactobacillus rhamnosus against clinical Multidrug Resistant (MDR) strains of Acinetobacter baumannii, Escherichia coli, and Staphylococcus aureus (MRSA). Cell-bound BS from both L. jensenii and L. rhamnosus were extracted and isolated. The surface activities of crude BS samples were evaluated using an oil spreading assay. The antimicrobial, anti-adhesive and anti-biofilm activities of both BS against the above mentioned MDR pathogens were determined. Results Surface activities for both BS ranged from 6.25 to 25 mg/ml with clear zones observed between 7 and 11 cm. BS of both L. jensenii and L. rhamnosus showed antimicrobial activities against A. baumannii, E. coli and S. aureus at 25-50 mg/ml. Anti-adhesive and anti-biofilm activities were also observed for the aforementioned pathogens between 25 and 50 mg/ml. Finally, analysis by electron microscope indicated that the BS caused membrane damage for A. baumannii and pronounced cell wall damage in S. aureus. Conclusion Our results indicate that BS isolated from two Lactobacilli strains has antibacterial properties against MDR strains of A. baumannii, E. coli and MRSA. Both BS also displayed anti-adhesive and anti-biofilm abilities against A. baumannii, E. coli and S. aureus. Together, these capabilities may open up possibilities for BS as an alternative therapeutic approach for the prevention and/or treatment of hospital-acquired infections. PMID:25124936

  6. Lactococci and lactobacilli as mucosal delivery vectors for therapeutic proteins and DNA vaccines

    PubMed Central

    2011-01-01

    Food-grade Lactic Acid Bacteria (LAB) have been safely consumed for centuries by humans in fermented foods. Thus, they are good candidates to develop novel oral vectors, constituting attractive alternatives to attenuated pathogens, for mucosal delivery strategies. Herein, this review summarizes our research, up until now, on the use of LAB as mucosal delivery vectors for therapeutic proteins and DNA vaccines. Most of our work has been based on the model LAB Lactococcus lactis, for which we have developed efficient genetic tools, including expression signals and host strains, for the heterologous expression of therapeutic proteins such as antigens, cytokines and enzymes. Resulting recombinant lactococci strains have been tested successfully for their prophylactic and therapeutic effects in different animal models: i) against human papillomavirus type 16 (HPV-16)-induced tumors in mice, ii) to partially prevent a bovine β-lactoglobulin (BLG)-allergic reaction in mice and iii) to regulate body weight and food consumption in obese mice. Strikingly, all of these tools have been successfully transposed to the Lactobacillus genus, in recent years, within our laboratory. Notably, anti-oxidative Lactobacillus casei strains were constructed and tested in two chemically-induced colitis models. In parallel, we also developed a strategy based on the use of L. lactis to deliver DNA at the mucosal level, and were able to show that L. lactis is able to modulate the host response through DNA delivery. Today, we consider that all of our consistent data, together with those obtained by other groups, demonstrate and reinforce the interest of using LAB, particularly lactococci and lactobacilli strains, to develop novel therapeutic protein mucosal delivery vectors which should be tested now in human clinical trials. PMID:21995317

  7. The effect of polydextrose and probiotic lactobacilli in a Clostridium difficile–infected human colonic model

    PubMed Central

    Forssten, Sofia D.; Röytiö, Henna; Hibberd, Ashley A.; Ouwehand, Arthur C.

    2015-01-01

    Background Clostridium difficile is a natural resident of the intestinal microbiota; however, it becomes harmful when the normal intestinal microbiota is disrupted, and overgrowth and toxin production occurs. The toxins can cause bloating and diarrhoea, which may cause severe disease and have the potential to cause outbreaks in hospitals and other healthcare settings. Normally, antibiotic agents are used for treatment, although for some of the patients, these treatments provide only a temporary relief with a recurrence of C. difficile–associated diarrhoea. Objective The effects of polydextrose (PDX), Lactobacillus acidophilus NCFM, and L. paracasei Lpc-37 on the growth of C. difficile were investigated in an in vitro model of infected human large intestine. Design The semi-continuous colonic model is composed of four connected vessels inoculated with human faecal microbes and spiked with pathogenic C. difficile (DSM 1296). PDX in two concentrations (2 and 4%), NCFM, and Lpc-37 were fed to the system during the 2-day simulation, and the growth of C. difficile and several other microbial groups were monitored using quantitative polymerase chain reaction (qPCR) and 16S rDNA sequencing. Results The microbial community structure of the simulation samples was closely grouped according to treatment, and the largest shifts in the microbial composition were seen with PDX. The microbial diversity decreased significantly with 4% PDX, and the OTU containing C. difficile was significantly (p<0.01) decreased when compared to control and lactobacilli treatments. The mean numbers of C. difficile also decreased as detected by qPCR, although the reduction did not reach statistical significance. Conclusions The treatments influenced the colonic microbiota, and a trend for reduced numbers of C. difficile as well as alterations of several microbial groups could be detected. This suggests that PDX may be able to modulate the composition and/or function of the colonic microbiota in

  8. Comparative mRNA Expression Profiles of Riboflavin Biosynthesis Genes in Lactobacilli Isolated from Human Feces and Fermented Bamboo Shoots

    PubMed Central

    Thakur, Kiran; Tomar, Sudhir K.; Wei, Zhao-Jun

    2017-01-01

    With the aim to bioprospect potent riboflavin producing lactobacilli, the present study was carried out to evaluate the relative mRNA expression of riboflavin biosynthesis genes namely Rib 1, Rib 2, Rib 3, and Rib 4 from potent riboflavin producers obtained from our previous studies. All the four genes were successfully cloned and sequenced for further analysis by in silico procedures. As studied by non-denaturing Polyacrylamide gel electrophoresis, no difference in size of all the four genes among those of various lactobacilli was observed. The relative fold increase in mRNA expression in Rib 1, Rib 2, Rib 3, and Rib 4 genes has been observed to be 10-, 1-, 0.7-, and 8.5-fold, respectively. Due to increase in relative mRNA expression for all the Rib genes as well as phenotypic production attribute, KTLF1 strain was used further for expression studies in milk and whey. The fold increase in mRNA expression for all the four Rib genes was higher at 12 and 18 h in milk and whey respectively. After exposure to roseoflavin, resistant variant of KTLF1 showed considerable increase in expression of all the targets genes. This is the first ever study to compare the mRNA expression of riboflavin biosynthesis pathway genes in lactobacilli and it also under lines the effect of media and harvesting time which significantly affect the expression of rib genes. The use of roseoflavin-resistant strains capable of synthesizing riboflavin in milk and whey paves a way for an exciting and economically viable biotechnological approach to develop novel riboflavin bio-enriched functional foods. PMID:28367143

  9. Regulation of acetic acid production by homo- and heterofermentative lactobacilli in whole-wheat sour-doughs.

    PubMed

    Martínez-Anaya, M A; Llin, M L; Pilar Macías, M; Collar, C

    1994-09-01

    The efficiency of sour-dough as a possible preservative agent of microbial spoilage of bread depends on its acetic acid content. As a secondary metabolite of sugar fermentation by lactic acid bacteria, acetic acid may be promoted in the presence of O2 or H+ acceptors. This paper studies the influence of O2 and high fructose content products (pure sugar, invert sugar, fructose syrup) addition on acetic acid production by hetero- (Lactobacillus brevis 25a, B-21, L-62; L. sanfrancisco L-99) and homofermentative (L. plantarum B-39) lactobacilli in whole-wheat sour-doughs [280 and 250 dough yield (DY)]. The pH and total titratable acidity (TTA) of sour-doughs after 44 h fermentation varied with DY and strain. As expected, the addition of O2 promoted greater increases in TTA with heterofermentative lactobacilli (15-42%) than with L. plantarum (15%). Fructose addition was only effective for heterofermentative strains, but the overall effects were smaller than those observed for oxygenation. The ability of lactobacilli to produce acetic acid in sour-doughs without treatment varied from 0.16 g/100 g flour at 44 h (B-39, 280, 350 DY) to 0.47-0.65% (L-62, 280, 350 DY). The production of acetic acid was positively promoted by all treatments. Oxygenation was again the most effective way of inducing acetic acid production; increases ranged from 54% (B-21) to 269% (L-99, 350 DY). The addition of H+ acceptors had variable effects.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. In Vitro Evaluation of the Probiotic Potential of Halotolerant Lactobacilli Isolated from a Ripened Tropical Mexican Cheese.

    PubMed

    Melgar-Lalanne, Guiomar; Rivera-Espinoza, Yadira; Reyes Méndez, Ana Itzel; Hernández-Sánchez, Humberto

    2013-12-01

    Three halotolerant lactobacilli (Lactobacillus plantarum, L. pentosus, and L. acidipiscis) isolated from a ripened Mexican tropical cheese (double cream Chiapas cheese) were evaluated as potential probiotics and compared with two commercial probiotic strains (L. casei Shirota and L. plantarum 299v) from human origin. All the strains survived the in vitro gastrointestinal simulation from the oral cavity to the ileum. During the stomach simulation, all the strains survived in satiety conditions (60 min, pH 3.0, 3 g/L pepsin, 150 rpm) and only L. pentosus could not survive under fasting conditions (60 min, pH 2.0, 3 g/L pepsin, 150 rpm). All the strains showed a strong hydrophilic character with low n-hexadecane and a variable chloroform affinity. L. plantarum showed a mucin adhesion rate similar to that of L. plantarum 299v and L. casei Shirota, while L. pentosus and L. acidipiscis had a lower mucin adhesion. The isolated halotolerant lactobacilli exhibited similar antimicrobial activity against some gram-positive and gram-negative pathogens in comparison with the two commercial strains. In addition, the proteinaceous character of the antimicrobial agents against the most pathogenic strains was demonstrated. The compounds showed a low molecular weight (less than 10 kDa). Besides, L. plantarum and L. acidipiscis were able to produce the enzyme β-galactosidase. Finally, L. pentosus was able to deconjugate taurocholic, taurodeoxycholic, glycocholic, and glycodeoxycholic acids better than the two commercial strains analyzed. All these results suggest that the halotolerant lactobacilli isolated from this ripened Mexican cheese could be potentially probiotic. This is the first time that halotolerant lactic acid bacteria have been shown to have probiotic properties.

  11. Highly Efficient Gluten Degradation by Lactobacilli and Fungal Proteases during Food Processing: New Perspectives for Celiac Disease▿

    PubMed Central

    Rizzello, Carlo G.; De Angelis, Maria; Di Cagno, Raffaella; Camarca, Alessandra; Silano, Marco; Losito, Ilario; De Vincenzi, Massimo; De Bari, Maria D.; Palmisano, Francesco; Maurano, Francesco; Gianfrani, Carmen; Gobbetti, Marco

    2007-01-01

    Presently, the only effective treatment for celiac disease is a life-long gluten-free diet. In this work, we used a new mixture of selected sourdough lactobacilli and fungal proteases to eliminate the toxicity of wheat flour during long-time fermentation. Immunological (R5 antibody-based sandwich and competitive enzyme-linked immunosorbent assay [ELISA] and R5 antibody-based Western blot), two-dimensional electrophoresis, and mass spectrometry (matrix-assisted laser desorption ionization-time of flight, strong-cation-exchange-liquid chromatography/capillary liquid chromatography-electrospray ionization-quadrupole-time of flight [SCX-LC/CapLC-ESI-Q-TOF], and high-pressure liquid chromatography-electrospray ionization-ion trap mass spectrometry) analyses were used to determine the gluten concentration. Assays based on the proliferation of peripheral blood mononuclear cells (PBMCs) and gamma interferon production by PBMCs and intestinal T-cell lines (iTCLs) from 12 celiac disease patients were used to determine the protein toxicity of the pepsin-trypsin digests from fermented wheat dough (sourdough). As determined by R5-based sandwich and competitive ELISAs, the residual concentration of gluten in sourdough was 12 ppm. Albumins, globulins, and gliadins were completely hydrolyzed, while ca. 20% of glutenins persisted. Low-molecular-weight epitopes were not detectable by SCX-LC/CapLC-ESI-Q-TOF mass spectrometry and R5-based Western blot analyses. The kinetics of the hydrolysis of the 33-mer by lactobacilli were highly efficient. All proteins extracted from sourdough activated PBMCs and induced gamma interferon production at levels comparable to the negative control. None of the iTCLs demonstrated immunoreactivity towards pepsin-trypsin digests. Bread making was standardized to show the suitability of the detoxified wheat flour. Food processing by selected sourdough lactobacilli and fungal proteases may be considered an efficient approach to eliminate gluten toxicity

  12. Advanced application of bovine intestinal epithelial cell line for evaluating regulatory effect of lactobacilli against heat-killed enterotoxigenic Escherichia coli-mediated inflammation

    PubMed Central

    2013-01-01

    Background Previously, a bovine intestinal epithelial cell line (BIE cells) was successfully established. This work hypothesized that BIE cells are useful in vitro model system for the study of interactions of microbial- or pathogen-associated molecular patterns (MAMPs or PAMPs) with bovine intestinal epithelial cells and for the selection of immunoregulatory lactic acid bacteria (LAB). Results All toll-like receptor (TLR) genes were expressed in BIE cells, being TLR4 one of the most strongly expressed. We demonstrated that heat-stable PAMPs of enterotoxigenic Escherichia coli (ETEC) significantly enhanced the production of IL-6, IL-8, IL-1α and MCP-1 in BIE cells by activating both NF-κB and MAPK pathways. We evaluated the capacity of several lactobacilli strains to modulate heat-stable ETEC PAMPs-mediated inflammatory response in BIE cells. Among these strains evaluated, Lactobacillus casei OLL2768 attenuated heat-stable ETEC PAMPs-induced pro-inflammatory response by inhibiting NF-κB and p38 signaling pathways in BIE cells. Moreover, L. casei OLL2768 negatively regulated TLR4 signaling in BIE cells by up-regulating Toll interacting protein (Tollip) and B-cell lymphoma 3-encoded protein (Bcl-3). Conclusions BIE cells are suitable for the selection of immunoregulatory LAB and for studying the mechanisms involved in the protective activity of immunobiotics against pathogen-induced inflammatory damage. In addition, we showed that L. casei OLL2768 functionally modulate the bovine intestinal epithelium by attenuating heat-stable ETEC PAMPs-induced inflammation. Therefore L. casei OLL2768 is a good candidate for in vivo studying the protective effect of LAB against intestinal inflammatory damage induced by ETEC infection or heat-stable ETEC PAMPs challenge in the bovine host. PMID:23497067

  13. Comparative evaluation of three Lactobacilli with strain-specific activities for rats when supplied in drinking water.

    PubMed

    Guo, Xiao-Hua; Zhao, Zhi-Dan; Nam, Hyang-Mi; Kim, Jae-Myung

    2012-11-01

    To test the in vivo benefits of three lactobacilli and to compare their different efficacies based on strain-specific activities by using rats as an experimental model, a growth-promotion and a challenge trial were conducted. The three strains, Lactobacillus salivarius G1-1, Lactobacillus reuteri G22-2, and Lactobacillus reuteri G8-5 shared antimicrobial, bile-salt-hydrolase and amylolytic activities in vitro, respectively. In the 17 day growth-promotion trial, 48 rats were allotted to four treatments with 12 replicates per treatment: a control group, which received saline, as well as three experimental groups, which received 10(8) cells/ml of one of the three lactobacilli in saline suspension. The results showed that compared with the control group, L. reuteri G8-5 significantly improved feed efficiency and decreased fecal pH values on days 8 and 17, concomitant with reduced faecal coliform counts on d 17 (p < 0.05). All treatments with lactobacilli caused an increase in the moisture content of the faeces and a decrease in the serum total cholesterol and blood urea nitrogen levels. High-density lipoprotein cholesterol was only elevated for rats which received L. reuteri G22-2. In the Salmonella-challenge trial, 40 rats were allotted to five treatments (8 replicates per treatment) which consisted of a positive control (infected, no Lactobacillus pretreatment), a negative control (uninfected, no Lactobacillus pretreatment) and three Lactobacillus-pretreated groups (10(9) cells/ml in saline). The results showed that rats in all Lactobacillus pretreated groups were protected from infection with significantly higher weight gain, feed intake and feed efficiency compared with positive control rats (p < 0.05). Rats treated with L. salivarius G1-1 and L. reuteri G22-2 tended to exhibit higher weight gains than those pretreated with L. reuteri G8-5. Significantly lower Salmonella shedding in faeces, Salmonella numbers in the spleen and the relative weight of the spleen

  14. Screening of Probiotic Activities of Lactobacilli Strains Isolated from Traditional Tibetan Qula, A Raw Yak Milk Cheese

    PubMed Central

    Zhang, Bei; Wang, Yanping; Tan, Zhongfang; Li, Zongwei; Jiao, Zhen; Huang, Qunce

    2016-01-01

    In this study, 69 lactobacilli isolated from Tibetan Qula, a raw yak milk cheese, were screened for their potential use as probiotics. The isolates were tested in terms of: Their ability to survive at pH 2.0, pH 3.0, and in the presence of 0.3% bile salts; tolerance of simulated gastric and intestinal juices; antimicrobial activity; sensitivity against 11 specific antibiotics; and their cell surface hydrophobicity. The results show that out of the 69 strains, 29 strains (42%) had survival rates above 90% after 2 h of incubation at pH values of 2.0 or 3.0. Of these 29 strains, 21 strains showed a tolerance for 0.3% bile salt. Incubation of these 21 isolates in simulated gastrointestinal fluid for 3 h revealed survival rates above 90%; the survival rate for 20 of these isolates remained above 90% after 4 h of incubation in simulated intestinal fluid. The viable counts of bacteria after incubation in simulated gastric fluid for 3 h and simulated intestinal fluid for 4 h were both significantly different compared with the counts at 0 h (p<0.001). Further screening performed on the above 20 isolates indicated that all 20 lactobacilli strains exhibited inhibitory activity against Micrococcus luteus ATCC 4698, Bacillus subtilis ATCC 6633, Listeria monocytogenes ATCC 19115, and Salmonella enterica ATCC 43971. Moreover, all of the strains were resistant to vancomycin and streptomycin. Of the 20 strains, three were resistant to all 11 elected antibiotics (ciprofloxacin, erythromycin, tetracycline, penicillin G, ampicillin, streptomycin, polymyxin B, vancomycin, chloramphenicol, rifampicin, and gentamicin) in this study, and five were sensitive to more than half of the antibiotics. Additionally, the cell surface hydrophobicity of seven of the 20 lactobacilli strains was above 70%, including strains Lactobacillus casei 1,133 (92%), Lactobacillus plantarum 1086-1 (82%), Lactobacillus casei 1089 (81%), Lactobacillus casei 1138 (79%), Lactobacillus buchneri 1059 (78

  15. Individual strains of Lactobacillus paracasei differentially inhibit human basophil and mouse mast cell activation

    PubMed Central

    Cassard, Lydie; Lalanne, Ana Inés; Garault, Peggy; Cotillard, Aurélie; Chervaux, Christian; Wels, Michiel; Smokvina, Tamara

    2016-01-01

    Abstract Introduction The microbiota controls a variety of biological functions, including immunity, and alterations of the microbiota in early life are associated with a higher risk of developing allergies later in life. Several probiotic bacteria, and particularly lactic acid bacteria, were described to reduce both the induction of allergic responses and allergic manifestations. Although specific probiotic strains were used in these studies, their protective effects on allergic responses also might be common for all lactobacilli. Methods To determine whether allergic effector cells inhibition is a common feature of lactobacilli or whether it varies among lactobacilli strains, we compared the ability of 40 strains of the same Lactobacillus paracasei species to inhibit IgE‐dependent mouse mast cell and human basophil activation. Results We uncovered a marked heterogeneity in the inhibitory properties of the 40 Lactobacillus strains tested. These segregated into three to four clusters depending on the intensity of inhibition. Some strains inhibited both mouse mast cell and human basophil activation, others strains inhibited only one cell type and another group induced no inhibition of activation for either cell type. Conclusions Individual Lactobacillus strains of the same species differentially inhibit IgE‐dependent activation of mouse mast cells and human basophils, two cell types that are critical in the onset of allergic manifestations. Although we failed to identify specific bacterial genes associated with inhibition by gene‐trait matching analysis, our findings demonstrate the complexity of the interactions between the microbiota and the host. These results suggest that some L. paracasei strains might be more beneficial in allergies than others strains and provide the bases for a rational screening of lactic acid bacteria strains as next‐generation probiotics in the field of allergy. PMID:27621812

  16. Utilization of physiological and taxonomic fluorescent probes to study Lactobacilli cells and response to pH challenge.

    PubMed

    Olszewska, Magdalena A; Kocot, Aleksandra M; Nynca, Anna; Łaniewska-Trokenheim, Łucja

    2016-11-01

    pH stress is recognized as an important feature for Lactobacillus in relation to lifestyle and commercial utility. Hence, this study aims to investigate the cell function of Lactobacilli cells subjected to pHs between 7.0 and 2.0. For this purpose, the Lactobacilli isolates of vegetable origin were first hybridized with fluorescent oligonucleotide rRNA probes for detecting Lactobacillus species. Then, cells were exposed to pH stress and labelled with fluorescent probes, carboxyfluorescein diacetate (CFDA) and propidium iodine (PI), which provided the insight into esterase activity and membrane integrity of cells. Among isolates, fluorescence in situ hybridization (FISH) enabled us to specifically detect L. plantarum and L. brevis. Interestingly, FCM analysis revealed that at pHs between 7.0 and 4.0 the cell membrane was intact, while after the exposure at pH 3.0, and 2.0 became perturbed or impaired. Finally, L. brevis and L. plantarum differed from each other in fluorescence labeling behaviour and culturability. However, the results showed that the same standard protocol for labeling enables discrimination of subpopulations of tested species. Depending on the species, the substantial culturability loss was observed at pH 3.0 and 2.0. These results suggest that the taxonomic and physiological fluorescent probes could be suitable for in situ detection of specific bacteria and rapid assessment of the physiological status of cells.

  17. Structural and immunomodulatory differences among lactobacilli exopolysaccharides isolated from intestines of mice with experimentally induced inflammatory bowel disease

    PubMed Central

    Górska, Sabina; Sandstrőm, Corine; Wojas-Turek, Justyna; Rossowska, Joanna; Pajtasz-Piasecka, Elżbieta; Brzozowska, Ewa; Gamian, Andrzej

    2016-01-01

    Characteristic changes in the microbiota biostructure and a decreased tolerance to intestinal bacteria have been associated with inflammatory bowel disease (IBD). However, few studies have examined the constituents of the intestinal microbiota, including the surface molecules of the bacteria, in healthy and IBD subsets. Here, we compare the chemical structures and immunomodulatory properties of the exopolysaccharides (EPS) of lactobacilli isolated from mice with induced IBD (IBD “+”) versus those of healthy mice (IBD “−”). Classical structural analyses were performed using nuclear magnetic resonance spectroscopy and mass spectrometry. Immunomodulatory properties were assessed by stimulation of dendritic cells derived from mouse bone marrow or human peripheral mononuclear blood cells. Our results revealed that EPS produced by IBD “+” species are structurally different from those isolated from IBD “−”. Moreover, the structurally different EPS generate different immune responses by dendritic cells. We speculate that resident strains could, upon gut inflammation, switch to producing EPS with specific motifs that are absent from lactobacilli IBD “−”, and/or that bacteria with a particular EPS structure might inhabit the inflamed intestinal mucosa. This study may shed light on the role of EPS in IBD and help the development of a specific probiotic therapy for this disease. PMID:27869188

  18. Use of MRSD medium and the hydrophobic grid membrane filter technique to differentiate between pediococci and lactobacilli in fermented meat and starter cultures.

    PubMed

    Holley, R A; Millard, G E

    1988-10-01

    Modifications of MRS medium were made by incorporation of 0.1 M L-arginine-HCl, 0.0025% phenol red, 100 IU polymyxin B sulfate, by deletion of meat extract, use of only 1.2% (w/v) glucose and increase of Mn2+ to 1000 ppm. In addition, adoption of the hydrophobic grid membrane filter (HGMF) system with 0.025% Fast Green FCF dye and adjustment of the agar medium to pH 5.5 gave MRSD (differential) medium. Incubation at 25 degrees C anaerobically under N2 or CO2 followed by a post-growth staining procedure involving use of 0.4% (w/v) bromocresol purple yielded conditions under which pediococci colonies were blue whereas homo- and heterofermentative lactobacilli were green in color. Under these conditions, 7 pediococci, 16 lactobacilli, and 18 commercial meat starter cultures were successfully analyzed by plate count to yield a differential assessment of the lactobacilli and pediococci present without interference from the 9 other genera tested. Streptococcus lactis and Leuconostoc spp. produced blue and green colonies, respectively, at 25 degrees C which might interference but these organisms are not present in significant numbers in fermented meats. Pediococcus parvulus and Streptococcus faecalis produced green and blue colonies, respectively, but their very poor growth at 25 degrees C prevented their interference. Use of the developed MRSD medium was described for enumeration of both pediococci and lactobacilli in starter cultures and in fermenting dry sausages to enable documentation of starter culture performance.

  19. Novel antimicrobial peptides that inhibit gram positive bacterial exotoxin synthesis.

    PubMed

    Merriman, Joseph A; Nemeth, Kimberly A; Schlievert, Patrick M

    2014-01-01

    Gram-positive bacteria, such as Staphylococcus aureus, cause serious human illnesses through combinations of surface virulence factors and secretion of exotoxins. Our prior studies using the protein synthesis inhibitor clindamycin and signal transduction inhibitors glycerol monolaurate and α-globin and β-globin chains of hemoglobin indicate that their abilities to inhibit exotoxin production by S. aureus are separable from abilities to inhibit growth of the organism. Additionally, our previous studies suggest that inhibition of exotoxin production, in absence of ability to kill S. aureus and normal flora lactobacilli, will prevent colonization by pathogenic S. aureus, while not interfering with lactobacilli colonization. These disparate activities may be important in development of novel anti-infective agents that do not alter normal flora. We initiated studies to explore the exotoxin-synthesis-inhibition activity of hemoglobin peptides further to develop potential agents to prevent S. aureus infections. We tested synthesized α-globin chain peptides, synthetic variants of α-globin chain peptides, and two human defensins for ability to inhibit exotoxin production without significantly inhibiting S. aureus growth. All of these peptides were weakly or not inhibitory to bacterial growth. However, the peptides were inhibitory to exotoxin production with increasing activity dependent on increasing numbers of positively-charged amino acids. Additionally, the peptides could be immobilized on agarose beads or have amino acid sequences scrambled and still retain exotoxin-synthesis-inhibition. The peptides are not toxic to human vaginal epithelial cells and do not inhibit growth of normal flora L. crispatus. These peptides may interfere with plasma membrane signal transduction in S. aureus due to their positive charges.

  20. Transcriptomic Analysis of the Innate Antiviral Immune Response in Porcine Intestinal Epithelial Cells: Influence of Immunobiotic Lactobacilli.

    PubMed

    Albarracin, Leonardo; Kobayashi, Hisakazu; Iida, Hikaru; Sato, Nana; Nochi, Tomonori; Aso, Hisashi; Salva, Susana; Alvarez, Susana; Kitazawa, Haruki; Villena, Julio

    2017-01-01

    Lactobacillus rhamnosus CRL1505 and Lactobacillus plantarum CRL1506 are immunobiotic strains able to increase protection against viral intestinal infections as demonstrated in animal models and humans. To gain insight into the host-immunobiotic interaction, the transcriptomic response of porcine intestinal epithelial (PIE) cells to the challenge with viral molecular associated pattern poly(I:C) and the changes in the transcriptomic profile induced by the immunobiotics strains CRL1505 and CRL1506 were investigated in this work. By using microarray technology and reverse transcription PCR, we obtained a global overview of the immune genes involved in the innate antiviral immune response in PIE cells. Stimulation of PIE cells with poly(I:C) significantly increased the expression of IFN-α and IFN-β, several interferon-stimulated genes, cytokines, chemokines, adhesion molecules, and genes involved in prostaglandin biosynthesis. It was also determined that lactobacilli differently modulated immune gene expression in poly(I:C)-challenged PIE cells. Most notable changes were found in antiviral factors (IFN-α, IFN-β, NPLR3, OAS1, OASL, MX2, and RNASEL) and cytokines/chemokines (IL-1β, IL-6, CCL4, CCL5, and CXCL10) that were significantly increased in lactobacilli-treated PIE cells. Immunobiotics reduced the expression of IL-15 and RAE1 genes that mediate poly(I:C) inflammatory damage. In addition, lactobacilli treatments increased the expression PLA2G4A, PTGES, and PTGS2 that are involved in prostaglandin E2 biosynthesis. L. rhamnosus CRL1505 and L. plantarum CRL1506 showed quantitative and qualitative differences in their capacities to modulate the innate antiviral immune response in PIE cells, which would explain the higher capacity of the CRL1505 strain when compared to CRL1506 to protect against viral infection and inflammatory damage in vivo. These results provided valuable information for the deeper understanding of the host-immunobiotic interaction and their

  1. Transcriptomic Analysis of the Innate Antiviral Immune Response in Porcine Intestinal Epithelial Cells: Influence of Immunobiotic Lactobacilli

    PubMed Central

    Albarracin, Leonardo; Kobayashi, Hisakazu; Iida, Hikaru; Sato, Nana; Nochi, Tomonori; Aso, Hisashi; Salva, Susana; Alvarez, Susana; Kitazawa, Haruki; Villena, Julio

    2017-01-01

    Lactobacillus rhamnosus CRL1505 and Lactobacillus plantarum CRL1506 are immunobiotic strains able to increase protection against viral intestinal infections as demonstrated in animal models and humans. To gain insight into the host–immunobiotic interaction, the transcriptomic response of porcine intestinal epithelial (PIE) cells to the challenge with viral molecular associated pattern poly(I:C) and the changes in the transcriptomic profile induced by the immunobiotics strains CRL1505 and CRL1506 were investigated in this work. By using microarray technology and reverse transcription PCR, we obtained a global overview of the immune genes involved in the innate antiviral immune response in PIE cells. Stimulation of PIE cells with poly(I:C) significantly increased the expression of IFN-α and IFN-β, several interferon-stimulated genes, cytokines, chemokines, adhesion molecules, and genes involved in prostaglandin biosynthesis. It was also determined that lactobacilli differently modulated immune gene expression in poly(I:C)-challenged PIE cells. Most notable changes were found in antiviral factors (IFN-α, IFN-β, NPLR3, OAS1, OASL, MX2, and RNASEL) and cytokines/chemokines (IL-1β, IL-6, CCL4, CCL5, and CXCL10) that were significantly increased in lactobacilli-treated PIE cells. Immunobiotics reduced the expression of IL-15 and RAE1 genes that mediate poly(I:C) inflammatory damage. In addition, lactobacilli treatments increased the expression PLA2G4A, PTGES, and PTGS2 that are involved in prostaglandin E2 biosynthesis. L. rhamnosus CRL1505 and L. plantarum CRL1506 showed quantitative and qualitative differences in their capacities to modulate the innate antiviral immune response in PIE cells, which would explain the higher capacity of the CRL1505 strain when compared to CRL1506 to protect against viral infection and inflammatory damage in vivo. These results provided valuable information for the deeper understanding of the host–immunobiotic interaction and their

  2. Phenotypic and genotypic screening of human-originated lactobacilli for vitamin B12 production potential: process validation by micro-assay and UFLC.

    PubMed

    Bhushan, Bharat; Tomar, S K; Mandal, Surajit

    2016-08-01

    Vitamin B12 (B12) production is a strain specific, rare and hidden functional attribute of lactobacilli and a cogent protocol for selection of such isolates from the herd of lactobacilli is required. The present study included isolation of lactobacilli from human samples (milk and fecal), screening them by a polyphasic (three-phase) methodology for probable B12 production potential and validating the screening protocol by exploring selected strains for in vitro vitamin production (two-phase fermentation) and quantification [micro-assay and ultra fast liquid chromatography (UFLC)]. Fifty-nine Lactobacillus strains were recovered from tested biological samples. Contrary to screening inapplicabilities of first [growth potential (GP) in B12-free medium] and second phases (GP in B12-free and cobalt chloride-supplemented conditions), third phase (cbiK gene detection on genomic DNA) alone was revealed as a validated strategy for selection of two probable B12-producing lactobacilli. Microbiological assay confirmed production and bioavailability of produced vitamin, while UFLC testing validated the results by precisely quantifying the cyanocobalamin (industrially produced bio-available form of B12) in cell extracts of both possible B12 producers [BHM10 (10.91 ± 1.55 μg/l) and BCF20 (23.90 ± 1.73 μg/l)] and positive standard [Lactobacillus reuteri DSM20016 (20.03 ± 4.17 μg/l)]. Moreover, this study generates a novel report for genomic detection, partial amplification and sequencing of cbiK gene in Lactobacillus plantarum species (both BHM10 and BCF20). In conclusion, contrary to first two phases, cbiK gene detection strategy successfully selects B12-producing strains from a group of human-originated lactobacilli and can be used in the future for similar screening studies.

  3. Effectiveness of vaginal tablets containing lactobacilli versus pH tablets on vaginal health and inflammatory cytokines: a randomized, double-blind study.

    PubMed

    Hemalatha, R; Mastromarino, P; Ramalaxmi, B A; Balakrishna, N V; Sesikeran, B

    2012-11-01

    The purpose of this study was to evaluate the effectiveness of lactobacilli on vaginal health and proinflammatory cytokines. Sixty-seven patients with bacterial vaginosis (BV), 50 with intermediate flora and 42 with normal vaginal flora were enrolled in this double-blind study. The subjects were randomized to receive probiotic lactobacilli vaginal tablets (L. brevis CD2, L. salivarius subsp. salicinius, L. plantarum) or the vaginal pH tablet (active comparator). Cervico-vaginal lavage was collected to measure the concentrations of IL-1β, TNFα and IL-6 by ELISA. Neutral sphingomyelinase activity was also quantified in both arms before and after treatment. The probiotic vaginal tablet was well tolerated and no side effects were reported. The study demonstrated a cure rate of nearly 80 %; i.e., 32 % of the women could restore normal vaginal flora and 47 % had improved Nugent score, whereas 20 % of the subjects did not clear BV in the first follow-up (after 8 days treatment). The pH tablet containing pH lowering compounds induced resolution of BV and restoration of normal vaginal flora in 74 % and 26 %, respectively. The lactobacilli tablet was found to be better than the pH tablet in preventing BV in healthy subjects. A significant reduction in IL-1β and IL-6 vaginal cytokines was observed after treatment with lactobacilli, while the active comparator did not have any effect on local proinflammatory cytokines. Vaginal neutral sphingomyelinase activity was not modified in either group. Vaginal tablets containing lactobacilli can cure BV and reduce vaginal inflammatory response.

  4. The effect of tongue scraper on mutans streptococci and lactobacilli in patients with caries and periodontal disease.

    PubMed

    Almas, Khalid; Al-Sanawi, Essam; Al-Shahrani, Bander

    2005-03-01

    Tongue cleaning is an ancient habit. Recent literature has shown that tongue cleaning leads to healthy oral environment. The aims of this study were to assess the effect of tongue scraper among male adult patients with caries and periodontal disease, on Mutans streptococci (MS) and Lactobacilli (Lb) bacteria and secondly to assess the effect on self perceived oral malodour. Sixty male patients completed the study. The age ranged from 20-55 years (32 +/- 9.53). Fifty percent of the subjects were with university education level. Mean DMFT score was 9.17 (+/-5.46), while 88% of the subjects were with early to moderate periodontitis assessed by CPITN. Thirty one percent of the subjects were smoker, while 86.7% had tea/coffee drinking habit and tooth brushing. Only 28% claimed of using miswak (chewing stick). All patients were advised to use a tongue scraper twice daily for at least 2 minutes per day for 7 days. No effort was made to change tooth brushing or dietary habits of patients. Self perceived oral malodour was reported by 41.7% at baseline and 30% after use of tongue scraper. Salivary count of Mutans Streptococci and Lactobacilli had significant decrease 3.37 (+/- 0.71) to 2.27 (+/- 0.80) and 3.22 (+/- 0.85) to 2.32 (+/- 0.87) respectively (P = 0.000). It was concluded that tongue scraping twice daily for 7 days had significant effect on MS and Lb bacteria and also decreased oral malodour

  5. Microbiological characterization of wet wheat distillers' grain, with focus on isolation of lactobacilli with potential as probiotics.

    PubMed

    Pedersen, C; Jonsson, H; Lindberg, J E; Roos, S

    2004-03-01

    Wet wheat distillers' grain (WWDG), a residue from ethanol fermentation, was examined from a microbiological perspective. After storage, WWDG was characterized by a high content of lactobacilli, nondetectable levels of other bacteria, occasional occurrence of yeasts, and a pH of about 3.6 and contained a mixture of lactic acid, acetic acid, and ethanol. The composition of lactobacilli in WWDG was simple, including primarily the species Lactobacillus amylolyticus, Lactobacillus panis, and Lactobacillus pontis, as determined by 16S rRNA gene sequencing. Since the use of WWDG as pig feed has indicated a health-promoting function, some relevant characteristics of three strains of each of these species were examined together with basal physiological parameters, such as carbohydrate utilization and growth temperature. Seven of the strains were isolated from WWDG, and two strains from pig feces were included for comparison. It was clear that all three species could grow at temperatures of 45 to 50 degrees C, with L. amylolyticus being able to grow at temperatures as high as 54 degrees C. This finding could be the explanation for the simple microflora of WWDG, where a low pH together with a high temperature during storage would select for these organisms. Some strains of L. panis and L. pontis showed prolonged survival at pH 2.5 in synthetic stomach juice and good growth in the presence of porcine bile salt. In addition, members of all three species were able to bind to immobilized mucus material in vitro. Especially the isolates from pig feces but, interestingly, some isolates from WWDG as well possessed properties that might be of importance for colonization of the gastrointestinal tracts of pigs.

  6. Urea Hydrogen Peroxide Reduces the Numbers of Lactobacilli, Nourishes Yeast, and Leaves No Residues in the Ethanol Fermentation

    PubMed Central

    Narendranath, N. V.; Thomas, K. C.; Ingledew, W. M.

    2000-01-01

    Urea hydrogen peroxide (UHP) at a concentration of 30 to 32 mmol/liter reduced the numbers of five Lactobacillus spp. (Lactobacillus plantarum, L. paracasei, Lactobacillus sp. strain 3, L. rhamnosus, and L. fermentum) from ∼107 to ∼102 CFU/ml in a 2-h preincubation at 30°C of normal-gravity wheat mash at ∼21 g of dissolved solids per ml containing normal levels of suspended grain particles. Fermentation was completed 36 h after inoculation of Saccharomyces cerevisiae in the presence of UHP, even when wheat mash was deliberately contaminated (infected) with L. paracasei at ∼107 CFU/ml. There were no significant differences in the maximum ethanol produced between treatments when urea hydrogen peroxide was used to kill the bacteria and controls (in which no bacteria were added). However, the presence of L. paracasei at ∼107 CFU/ml without added agent resulted in a 5.84% reduction in the maximum ethanol produced compared to the control. The bactericidal activity of UHP is greatly affected by the presence of particulate matter. In fact, only 2 mmol of urea hydrogen peroxide per liter was required for disinfection when mashes had little or no particulate matter present. No significant differences were observed in the decomposition of hydrogen peroxide in normal-gravity wheat mash at 30°C whether the bactericidal agent was added as H2O2 or as urea hydrogen peroxide. NADH peroxidase activity (involved in degrading H2O2) increased significantly (P = 0.05) in the presence of 0.75 mM hydrogen peroxide (sublethal level) in all five strains of lactobacilli tested but did not persist in cells regrown in the absence of H2O2. H2O2-resistant mutants were not expected or found when lethal levels of H2O2 or UHP were used. Contaminating lactobacilli can be effectively managed by UHP, a compound which when used at ca. 30 mmol/liter happens to provide near-optimum levels of assimilable nitrogen and oxygen that aid in vigorous fermentation performance by yeast. PMID:11010858

  7. Antifungal activity of lactobacilli and its relationship with 3-phenyllactic acid production.

    PubMed

    Cortés-Zavaleta, O; López-Malo, A; Hernández-Mendoza, A; García, H S

    2014-03-03

    In this study, 13 lactic acid bacteria (LAB) strains (including 5 Lactobacillus casei, 2 Lactobacillus rhamnosus, 2 Lactobacillus fermentum, 1 Lactobacillus acidophilus, 1 Lactobacillus plantarum, 1 Lactobacillus sakei, and 1 Lactobacillus reuteri species) were assessed for both their antifungal activity against four food spoilage molds (Colletotrichum gloeosporioides, Botrytis cinerea, Penicillium expansum, and Aspergillus flavus) and their capability to produce the novel antimicrobial compound 3-phenyllactic acid (PLA). Results demonstrated that all molds were sensitive to varying degrees to the cell-free supernatants (CFS) from LAB fermentations (p<0.05), with growth inhibitions ranging from 2.65% to 66.82%. The inhibition ability of CFS was not affected by a heating treatment (121°C, 20 min); however, it declined markedly when the pH of CFS was adjusted to 6.5. With the exception of L. plantarum NRRL B-4496 and L. acidophilus ATCC-4495, all other LAB strains produced PLA ranging from 0.021 to 0.275 mM. The high minimum inhibitory concentration for commercial PLA (3.01-36.10mM) suggests that it cannot be considered the only compound related with the antifungal potential of studied LAB and that synergistic effects may exist among other metabolism products.

  8. Quantitative detection and identification of tyramine-producing enterococci and lactobacilli in cheese by multiplex qPCR.

    PubMed

    Ladero, Victor; Fernández, María; Cuesta, Isabel; Alvarez, Miguel A

    2010-10-01

    Tyramine is the most abundant biogenic amine in fermented dairy products, in which it is produced through the microbial enzymatic decarboxylation of tyrosine. This activity has been detected in a variety of lactic acid bacteria mainly belonging to the genera Enterococcus and Lactobacillus. This paper describes a culture-independent qPCR method, based on the specific amplification of the tdc gene, for the detection, quantification and identification of bacteria with the ability to produce tyramine. This method was found to be specific and to show a wide dynamic range, thus allowing the quantification of these tdc+ bacterial groups among the complex microbiota of cheese. tdc qPCR was used to follow the development of tdc+ microbiota during the manufacture of a blue-veined cheese (Cabrales) made from raw milk. In this type of cheese, tdc+ enterococci seem to be responsible for the high concentrations of tyramine detected. The method was also used to identify and quantify tdc+ enterococci and lactobacilli in 18 commercially available cheeses. Different types and numbers of these microorganisms were found. Their relationships with the concentration of tyramine and technological factors are discussed.

  9. Roles of Probiotic Lactobacilli Inclusion in Helping Piglets Establish Healthy Intestinal Inter-environment for Pathogen Defense.

    PubMed

    Yang, Jiajun; Qian, Kun; Wang, Chonglong; Wu, Yijing

    2017-03-30

    The gastrointestinal tract of pigs is densely populated with microorganisms that closely interact with the host and with ingested feed. Gut microbiota benefits the host by providing nutrients from dietary substrates and modulating the development and function of the digestive and immune systems. An optimized gastrointestinal microbiome is crucial for pigs' health, and establishment of the microbiome in piglets is especially important for growth and disease resistance. However, the microbiome in the gastrointestinal tract of piglets is immature and easily influenced by the environment. Supplementing the microbiome of piglets with probiotic bacteria such as Lactobacillus could help create an optimized microbiome by improving the abundance and number of lactobacilli and other indigenous probiotic bacteria. Dominant indigenous probiotic bacteria could improve piglets' growth and immunity through certain cascade signal transduction pathways. The piglet body provides a permissive habitat and nutrients for bacterial colonization and growth. In return, probiotic bacteria produce prebiotics such as short-chain fatty acids and bacteriocins that benefit piglets by enhancing their growth and reducing their risk of enteric infection by pathogens. A comprehensive understanding of the interactions between piglets and members of their gut microbiota will help develop new dietary interventions that can enhance piglets' growth, protect piglets from enteric diseases caused by pathogenic bacteria, and maximize host feed utilization.

  10. Comparison of probiotic lactobacilli and bifidobacteria effects, immune responses and rotavirus vaccines and infection in different host species

    PubMed Central

    Vlasova, Anastasia N.; Kandasamy, Sukumar; Chattha, Kuldeep S.; Rajashekara, Gireesh; Saif, Linda J.

    2016-01-01

    Different probiotic strains of Lactobacillus and Bifidobacterium genera possess significant and widely acknowledged health-promoting and immunomodulatory properties. They also provide an affordable means for prevention and treatment of various infectious, allergic and inflammatory conditions as demonstrated in numerous human and animal studies. Despite the ample evidence of protective effects of these probiotics against rotavirus (RV) infection and disease, the precise immune mechanisms of this protection remain largely undefined, because of limited mechanistic research possible in humans and investigated in the majority of animal models. Additionally, while most human clinical probiotic trials are well-standardized using the same strains, uniform dosages, regimens of the probiotic treatments and similar host age, animal studies often lack standardization, have variable experimental designs, and non-uniform and sometime limited selection of experimental variables or observational parameters. This review presents selected data on different probiotic strains of lactobacilli and bifidobacteria and summarizes the knowledge of their immunomodulatory properties and the associated protection against RV disease in diverse host species including neonates. PMID:26809484

  11. Isolation and identification of new lactobacilli from goatling stomach and investigation of reuterin production in Lactobacillus reuteri strains.

    PubMed

    Kiňová Sepová, Hana; Bilková, Andrea

    2013-01-01

    Five new strains of lactobacilli isolated from goatling's stomach were identified by molecular-biological approaches. Profiles of fermentable saccharides, Gram staining, and cell morphology were also determined. They were identified as Lactobacillus reuteri (strains KO4b, KO4m, KO5) and as Lactobacillus plantarum (strains KG1z, KG4). In DNA samples of all newly isolated L. reuteri strains as well as in L. reuteri E (Lreu E; originated from lamb), the part of gldC gene, coding large subunit of glycerol dehydratase, that is necessary for 3-hydroxypropionaldehyde (3-HPA; reuterin) production, was amplified using two designed primer sets. However, the 3-HPA production was revealed only in the strain Lreu E. It produced five- or ten-fold lower amount of 3-HPA in comparison with probiotic L. reuteri ATCC 55730 in aerobic or anaerobic conditions, respectively. Moreover, Lreu E completely lost its production ability after ca. five passages in MRS medium. The co-incubation of Lreu E, but not other L. reuteri isolates, with Escherichia coli re-induced 3-HPA production. In the case of L. reuteri ATCC 55730, the 3-HPA production increased more than four times after co-incubation with E. coli.

  12. Immunomodulatory and antimicrobial efficacy of Lactobacilli against enteropathogenic infection of Salmonella typhi: In-vitro and in-vivo study.

    PubMed

    Mazaya, Basem; Hamzawy, Mohamed A; Khalil, Mahmoud A F; Tawkol, Wael M; Sabit, Hussein

    2015-12-01

    Salmonellosis-induced diarrhea, is one of the commonest cause of childhood mortality in developing countries. Using of probiotics is viewed as a promising means for reducing the pathogenic loads of bacterial infection. The current study aimed to evaluate the potential antimicrobial and immunomodulatory efficacy of isolated lactobacillus strains against the enteropathogenic effect of S. Typhi. Different Lactobacillus strains were isolated from 13 dairy products. Their antimicrobial activities were tested against different bacterial strains. Six groups of CD1 mice were treated for 8 days as follows: group (1) untreated control; group (2) was challenged with single inoculation S. typhi, and groups (3) and (4) were treated with Lactobacillus plantarum (LA5) or Lactobacillus paracsi (LA7) for 7 days, respectively. Groups (5) and (6) were challenged with S. typhi, and then treated with either LA5 or LA 7 for 7 days, respectively. Isolated Lactobacillus showed antimicrobial activity against wide range of bacterial strains. Salmonellosis showed high widal titer, induced significant disturbance of TNF and IL-1β, while sever changes of the histological patterns of the intestinal villi and hepatocytes have been illustrated. LA5 or LA7 succeeded to eradicate typhoid infection, restore the values of inflammatory cytokines to typical levels of control group, and improve histological pictures of intestinal and hepatic tissues. It can be concluded that lactobacilli are promising candidate in protection and eradication against bacterial infection induced by S. Typhi due to its antimicrobial, anti-inflammatory, and immunomodulatory activities.

  13. Exploring the relationship between exposure to technological and gastrointestinal stress and probiotic functional properties of lactobacilli and bifidobacteria.

    PubMed

    Amund, O D

    2016-09-01

    Strains of Lactobacillus and Bifidobacterium are considered probiotic because of their associated potential health benefits. Probiotics are commonly administered orally via incorporation into food products. Microorganisms for use as probiotics encounter stress conditions, which include acid, bile, osmotic, oxidative, heat and cold stresses. These can occur during processing and storage and during passage through the gastrointestinal tract, and can affect viability. Probiotic bacteria have to remain viable to confer any health benefits. Therefore, the ability to withstand technological and gastrointestinal stresses is crucial probiotic selection criteria. While the stress tolerance mechanisms of lactobacilli and bifidobacteria are largely understood, the impact of exposure to stressful conditions on the functional properties of surviving probiotic microorganisms is not clear. This review explores the potentially positive and negative relationships between exposure to stress conditions and probiotic functional properties, such as resistance to gastric acid and bile, adhesion and colonization potential, and tolerance to antibiotics. Protective strategies can be employed to combat negative effects of stress on functional properties. However, further research is needed to ascertain synergistic relationships between exposure to stress and probiotic properties.

  14. NOD Dendritic Cells Stimulated with Lactobacilli Preferentially Produce IL-10 versus IL-12 and Decrease Diabetes Incidence

    PubMed Central

    Manirarora, Jean N.; Parnell, Sarah A.; Hu, Yoon-Hyeon; Kosiewicz, Michele M.; Alard, Pascale

    2011-01-01

    Dendritic cells (DCs) from NOD mice produced high levels of IL-12 that induce IFNγ-producing T cells involved in diabetes development. We propose to utilize the microorganism ability to induce tolerogenic DCs to abrogate the proinflammatory process and prevent diabetes development. NOD DCs were stimulated with Lactobacilli (nonpathogenic bacteria targeting TLR2) or lipoteichoic acid (LTA) from Staphylococcus aureus (TLR2 agonist). LTA-treated DCs produced much more IL-12 than IL-10 and accelerated diabetes development when transferred into NOD mice. In contrast, stimulation of NOD DCs with L. casei favored the production of IL-10 over IL-12, and their transfer decreased disease incidence which anti-IL-10R antibodies restored. These data indicated that L. casei can induce NOD DCs to develop a more tolerogenic phenotype via production of the anti-inflammatory cytokine, IL-10. Evaluation of the relative production of IL-10 and IL-12 by DCs may be a very useful means of identifying agents that have therapeutic potential. PMID:21716731

  15. Evaluation of propidium monoazide real-time PCR for enumeration of probiotic lactobacilli microencapsulated in calcium alginate beads.

    PubMed

    Oketič, K; Matijašić, B Bogovič; Obermajer, T; Radulović, Z; Lević, S; Mirković, N; Nedović, V

    2015-01-01

    The aim of the study was to evaluate real-time PCR coupled with propidium monoazide (PMA) treatment for enumeration of microencapsulated probiotic lactobacilli microencapsulated in calcium alginate beads. Lactobacillus gasseri K7 (CCM 7710) and Lactobacillus delbrueckii subsp. bulgaricus (CCM 7712) were analysed by plate counting and PMA real-time PCR during storage at 4 °C for 90 days. PMA was effective in preventing PCR amplification of the target sequences of DNA released from heat-compromised bacteria. The values obtained by real-time PCR of non-treated samples were in general higher than those obtained by real-time PCR of PMA-treated samples or by plate counting, indicating the presence of sub-lethally injured cells. This study shows that plate count could not be completely replaced by culture independent method PMA real-time PCR for enumeration of probiotics, but may rather complement the well-established plate counting, providing useful information about the ratio of compromised bacteria in the samples.

  16. Comparison of probiotic lactobacilli and bifidobacteria effects, immune responses and rotavirus vaccines and infection in different host species.

    PubMed

    Vlasova, Anastasia N; Kandasamy, Sukumar; Chattha, Kuldeep S; Rajashekara, Gireesh; Saif, Linda J

    2016-04-01

    Different probiotic strains of Lactobacillus and Bifidobacterium genera possess significant and widely acknowledged health-promoting and immunomodulatory properties. They also provide an affordable means for prevention and treatment of various infectious, allergic and inflammatory conditions as demonstrated in numerous human and animal studies. Despite the ample evidence of protective effects of these probiotics against rotavirus (RV) infection and disease, the precise immune mechanisms of this protection remain largely undefined, because of limited mechanistic research possible in humans and investigated in the majority of animal models. Additionally, while most human clinical probiotic trials are well-standardized using the same strains, uniform dosages, regimens of the probiotic treatments and similar host age, animal studies often lack standardization, have variable experimental designs, and non-uniform and sometime limited selection of experimental variables or observational parameters. This review presents selected data on different probiotic strains of lactobacilli and bifidobacteria and summarizes the knowledge of their immunomodulatory properties and the associated protection against RV disease in diverse host species including neonates.

  17. Impact of adding Saccharomyces strains on fermentation, aerobic stability, nutritive value, and select lactobacilli populations in corn silage.

    PubMed

    Duniere, L; Jin, L; Smiley, B; Qi, M; Rutherford, W; Wang, Y; McAllister, T

    2015-05-01

    Bacterial inoculants can improve the conservation and nutritional quality of silages. Inclusion of the yeast Saccharomyces in the diet of dairy cattle has also been reported to be beneficial. The present study assessed the ability of silage to be used as a means of delivering Saccharomyces strains to ruminants. Two strains of Saccharomyces cerevisiae (strain 1 and 3)and 1 strain of Saccharomyces paradoxus (strain 2) were inoculated (10(3) cfu/g) individually onto corn forage that was ensiled in mini silos for 90 d. Fermentation characteristics, aerobic stability, and nutritive value of silages were determined and real-time quantitative PCR (RT-qPCR) was used to quantify S. cerevisiae, S.paradoxus, total Saccharomyces, fungal, and bacterial populations. Fermentation characteristics of silage inoculated with S1 were similar to control silage. Although strain 3 inoculation increased ash and decreased OM contents of silage (P = 0.017), no differences were observed in nutrient composition or fermentation profiles after 90 d of ensiling. Inoculation with Saccharomyces had no detrimental effect on the aerobic stability of silage. In vitro DM disappearance, gas production, and microbial protein synthesis were not affected by yeast inoculation.Saccharomyces strain 1 was quantified throughout ensiling, whereas strain 2 was detected only immediately after inoculation. Saccharomyces cerevisiae strain 3 was quantified until d 7 and detectable 90 d after ensiling. All inoculants were detected and quantified during aerobic exposure. Inoculation with Saccharomyces did not alter lactobacilli populations. Saccharomycetales were detected by RT-qPCR throughout ensiling in all silages. Both S. cerevisiae and S. paradoxus populations increased during aerobic exposure, demonstrating that the density of these yeast strains would increase between the time that silage was removed from storage and the time it was fed.

  18. Optimizing Production of Two Potential Probiotic Lactobacilli Strains Isolated from Piglet Feces as Feed Additives for Weaned Piglets

    PubMed Central

    Chiang, Ming-Lun; Chen, Hsi-Chia; Chen, Kun-Nan; Lin, Yu-Chun; Lin, Ya-Ting; Chen, Ming-Ju

    2015-01-01

    Two probiotic strains, Lactobacillus johnsonii x-1d-2 and Lactobacillus mucosae x-4w-1, originally isolated from piglet feces, have been demonstrated to possess antimicrobial activities, antibiotic resistances and interleukin-6 induction ability in RAW 267.4 macrophages in our previous study. These characteristics make L. johnsonii x-1d-2 and L. mucosae x-4w-1 good candidates for application in feed probiotics. In this study, soybeal meal, molasses and sodium acetate were selected to optimize the growth medium for cultivation of L. johnsonii x-1d-2 and L. mucosae x-4w-1. These two strains were then freeze-dried and mixed into the basal diet to feed the weaned piglets. The effects of L. johnsonii x-1d-2 and L. mucosae x-4w-1 on the growth performance and fecal microflora of weaned piglets were investigated. The results showed that the bacterial numbers of L. johnsonii x-1d-2 and L. mucosae x-4w-1 reached a maximum of 8.90 and 9.30 log CFU/mL, respectively, when growing in optimal medium consisting of 5.5% (wt/vol) soybean meal, 1.0% (wt/vol) molasses and 1.0% (wt/vol) sodium acetate. The medium cost was 96% lower than the commercial de Man, Rogosa and Sharpe medium. In a further feeding study, the weaned piglets fed basal diet supplemented with freeze-dried probiotic cultures exhibited higher (p<0.05) body weight gain, feed intake, and gain/feed ratio than weaned piglets fed basal diet. Probiotic feeding also increased the numbers of lactobacilli and decreased the numbers of E. coli in the feces of weaned piglets. This study demonstrates that L. johnsonii x-1d-2 and L. mucosae x-4w-1 have high potential to be used as feed additives in the pig industry. PMID:26104525

  19. Characterization of growth inhibition of oral bacteria by sophorolipid using a microplate-format assay.

    PubMed

    Solaiman, Daniel K Y; Ashby, Richard D; Uknalis, Joseph

    2017-05-01

    Sophorolipid (SL) is a class of glycolipid biosurfactant produced by yeast and has potent antimicrobial activity against many microorganisms. In this paper, a microplate-based method was developed to characterize the growth inhibition by SL on five representative species of caries-causing oral bacteria. Bacterial growth on microplate in the absence and presence of varying concentrations of SL was continuously monitored by recording the absorbance at 600nm of the cultures using a microplate reader. The results showed that SL completely inhibited the growth of the Lactobacilli at ≥1mg/ml and the Streptococci at much lower concentrations of ≥50μg/ml. More importantly, we further defined the mechanism of antimicrobial activity of SL by analyzing the pattern of the cell growth curves. SL at sublethal concentrations (<1mg/ml) is bactericidal towards the Lactobacilli; it lengthens the apparent cell-doubling time (Td) and decreases the final cell density (as indicated by A600nm) in a concentration-dependent manner. Against the oral Streptococci, on the other hand, SL at sublethal concentrations (<50μg/ml) is bacteriostatic; it delays the onset of cell growth in a concentration-dependent fashion, but once the cell growth is commenced there is no noticeable adverse effect on Td and the final A600nm. Scanning electron microscopic (SEM) study of L. acidophilus grown in sublethal concentration of SL reveals extensive structural damage to the cells. S. mutans grown in sublethal level of SL did not show morphological damage to the cells, but numerous protruding structures could be seen on the cell surface. At the respective lethal levels of SL, L. acidophilus cells were lysed (at 1mg/ml SL) and the cell surface structure of S. mutans (at 130μg/ml SL) was extensively deformed. In summary, this paper presents the first report on a detailed analysis of the effects of SL on Lactobacilli and Streptococci important to oral health and hygiene.

  20. Enumeration of lactobacilli in the fecal flora of infant using two different modified de-Man Rogosa Sharpe media under aerobic and anaerobic incubation.

    PubMed

    Mirlohi, M; Soleimanian-Zad, S; Sheikh-Zeiondin, M; Fazeli, Hossein

    2008-03-15

    Regarding the importance of the presence of intestinal lactobacilli and their population in infants, four different treatments were evaluated for Lactobacillus isolation efficiency via reduction in the growth of other groups of bacteria capable of growing on de-Man Rogosa Sharpe (MRS) medium from fecal samples of 11 Iranian infants. MRS-Vancomycin (1 mg L(-l)) was used as a base medium and application of lactic acid and aerobic incubation of inoculated plates were performed as selective factors. Each fecal sample was cultivated as duplicate on to the base medium with or without lactic acid to reduce the pH to 5.4 +/- 0.2. Half of the plates were incubated aerobically and the rest of them incubated under 10% CO2 concentration. Total count and Lactobacillus count of all samples were recorded according to the age differences of infants. The counts of false positive colonies were recorded with respect to their cell morphology and gram reaction in all treatments. Anaerobic incubation of lactic acid modified MRS-Vancomycin gave the most Lactobacillus percentage coverage, about 93% among the Lactobacillus positive samples. Using this treatment, the median Lactobacillus count yielded 8.29 log10 cfu g(-1) in the younger and 5.70 log10 cfu g(-1) in the elder group. It could be concluded that lactic acid might be a proper pH reducing agent when enumeration of lactobacilli from fecal samples is of interest.

  1. The effect of indigenous Neem Azadirachta indica [correction of (Adirachta indica)] mouth wash on Streptococcus mutans and lactobacilli growth.

    PubMed

    Vanka, A; Tandon, S; Rao, S R; Udupa, N; Ramkumar, P

    2001-01-01

    Neem is one of the most widely researched tropical tree, with almost all it's parts being put for a variety of uses. In the present study, the antibacterial effect of Neem mouthwash against salivary levels of streptococcus mutans and lactobacillus has been tested over a period of 2 months. Also it's effect in reversing incipient carious lesions was assessed. While streptococcus mutans was inhibited by Neem mouthwashes, with or without alcohol as well as chlorhexidine, lactobacillus growth was inhibited by chlorhexidine alone. The initial data appears to prove it's effect in inhibiting S. mutans and reversing incipient carious lesions, longer term clinical trials are essential.

  2. Specific vaginal lactobacilli suppress the inflammation induced by lipopolysaccharide stimulation through downregulation of toll-like receptor 4 expression in human embryonic intestinal epithelial cells

    PubMed Central

    TOBITA, Keisuke; WATANABE, Itsuki; SAITO, Masanori

    2016-01-01

    Vaginal lactobacilli (VLB) spread from the mother to the infant during vaginal delivery. However, the effects of VLB on infant intestinal function remain unclear. We investigated the probiotic function and immune effects of VLB on the human embryonic intestinal epithelial cell line INT-407. VLB survived artificial gastric juice and adhered to INT-407 cells. Exposure of INT-407 cells to VLB attenuated both the lipopolysaccharide (LPS)-induced stimulation of interleukin-8 and tumor necrosis factor alpha production and the LPS-stimulated upregulation of TLR4 expression. These results suggest that specific VLB suppresses the inflammation induced by LPS stimulation through downregulation of TLR4 expression in human embryonic intestinal epithelial cells. PMID:28243550

  3. The approximal bone height and intrabony defects in young adults, related to the salivary buffering capacity and counts of Streptococcus mutans and Lactobacilli.

    PubMed

    Wikner, S; Söder, P O; Frithiof, L; Wouters, F

    1990-01-01

    Using a computerized technique the bone height and prevalence of approximal periodontal intrabony defects were assessed on posterior bite-wing radiographs from 151 young adults. The results were related to the buffering capacity and counts of Streptococcus mutans and lactobacilli in whole stimulated saliva. The mean distance from the cement-enamel junction to the alveolar bone crest was greater in the high buffering group than in the low buffering group (p less than 0.05), and particularly in non-smokers (p less than 0.01). Intrabony defects were more common in the low buffering group (p less than 0.05) and in women (p less than 0.001).

  4. Influence of dietary supplementation with flaxseed and lactobacilli on the mucosal morphology and proliferative cell rate in the jejunal mucosa of piglets after weaning

    PubMed Central

    Jonecova, Zuzana; Toth, Stefan; Ciccocioppo, Rachele; Rodrigo, Luis; Kruzliak, Peter; Nemcova, Radomira

    2015-01-01

    The aim of the study was to investigate the influence of flaxseed and lactobacilli supplementation to the diet of piglets during the time period between 10 days before and 21 days after weaning. The morphometry of the jejunal mucosa and proliferative ratio of both epithelial and lamina propria cells were compared with those found in a group of piglets fed with the usual diet added with sunflower oil during the same time period. The addition of flaxseed oil to the diet significantly increased the crypt depth in comparison with both groups supplemented with sunflower (P < 0.05 and 0.001 respectively) on the weaning day. Moreover, the flaxseed addition caused a significant decrease in villus height (P < 0.01) and crypt depth (P < 0.01) 21 days postweaning in comparison with the sunflower group. The proliferative ratio of the epithelial cells in the sunflower group on the weaning day was significantly higher than in both flaxseed groups (P < 0.01). Paradoxically, significantly higher proliferative activity in the mucosal connective tissue in the group with flaxseed supplementation in comparison with the sunflower group was observed on the day of weaning, as well as 3 days later (P < 0.05 both). A combination of flaxseed with lactobacilli showed significantly lower proliferative activity in the connective tissue cells from weaning up to 7 days after weaning (P < 0.05 all) in comparison with the flaxseed group. PMID:25929724

  5. Influence of dietary supplementation with flaxseed and lactobacilli on the mucosal morphology and proliferative cell rate in the jejunal mucosa of piglets after weaning.

    PubMed

    Jonecova, Zuzana; Toth, Stefan; Ciccocioppo, Rachele; Rodrigo, Luis; Kruzliak, Peter; Nemcova, Radomira

    2015-06-01

    The aim of the study was to investigate the influence of flaxseed and lactobacilli supplementation to the diet of piglets during the time period between 10 days before and 21 days after weaning. The morphometry of the jejunal mucosa and proliferative ratio of both epithelial and lamina propria cells were compared with those found in a group of piglets fed with the usual diet added with sunflower oil during the same time period. The addition of flaxseed oil to the diet significantly increased the crypt depth in comparison with both groups supplemented with sunflower (P < 0.05 and 0.001 respectively) on the weaning day. Moreover, the flaxseed addition caused a significant decrease in villus height (P < 0.01) and crypt depth (P < 0.01) 21 days postweaning in comparison with the sunflower group. The proliferative ratio of the epithelial cells in the sunflower group on the weaning day was significantly higher than in both flaxseed groups (P < 0.01). Paradoxically, significantly higher proliferative activity in the mucosal connective tissue in the group with flaxseed supplementation in comparison with the sunflower group was observed on the day of weaning, as well as 3 days later (P < 0.05 both). A combination of flaxseed with lactobacilli showed significantly lower proliferative activity in the connective tissue cells from weaning up to 7 days after weaning (P < 0.05 all) in comparison with the flaxseed group.

  6. Lactate- and acetate-based cross-feeding interactions between selected strains of lactobacilli, bifidobacteria and colon bacteria in the presence of inulin-type fructans.

    PubMed

    Moens, Frédéric; Verce, Marko; De Vuyst, Luc

    2017-01-16

    Cross-feeding interactions were studied between selected strains of lactobacilli and/or bifidobacteria and butyrate-producing colon bacteria that consume lactate but are not able to degrade inulin-type fructans (ITF) in a medium for colon bacteria (supplemented with ITF as energy source and acetate when necessary). Degradation of oligofructose by Lactobacillus acidophilus IBB 801 and inulin by Lactobacillus paracasei 8700:2 and Bifidobacterium longum LMG 11047 resulted in the release of free fructose into the medium and the production of mainly lactate (lactobacilli) and acetate (B. longum LMG 11047). During bicultures of Lb. acidophilus IBB 801 and Anaerostipes caccae DSM 14662(T) on oligofructose, the latter strain converted lactate (produced by the former strain from oligofructose) into butyrate and gases, but only in the presence of acetate. During bicultures of Lb. paracasei 8700:2 and A. caccae DSM 14662(T) or Eubacterium hallii DSM 17630 on inulin, the butyrate-producing strains consumed low concentrations of lactate and acetate generated by inulin degradation by the Lactobacillus strain. As more acetate was produced during tricultures of Lb. paracasei 8700:2 and B. longum LMG 11047, which degraded inulin simultaneously, and A. caccae DSM 14662(T) or E. hallii DSM 17630, a complete conversion of lactate into butyrate and gases by these butyrate-producing strains occurred. Therefore, butyrate production by lactate-consuming, butyrate-producing colon bacterial strains incapable of ITF degradation, resulted from cross-feeding of monosaccharides and lactate by an ITF-degrading Lactobacillus strain and acetate produced by a Bifidobacterium strain.

  7. Anti-inflammatory and Intestinal Barrier-protective Activities of Commensal Lactobacilli and Bifidobacteria in Thoroughbreds: Role of Probiotics in Diarrhea Prevention in Neonatal Thoroughbreds.

    PubMed

    Tanabe, Soichi; Suzuki, Takuya; Wasano, Yuichiro; Nakajima, Fumihiko; Kawasaki, Hiroshi; Tsuda, Tomonori; Nagamine, Natsuko; Tsurumachi, Takashi; Sugaya, Kiyoshi; Akita, Hiroaki; Takagi, Misako; Takagi, Kunihiko; Inoue, Yoshinobu; Asai, Yo; Morita, Hidetoshi

    2014-01-01

    We previously isolated the commensal bacteria lactobacilli and bifidobacteria from the Thoroughbred intestine and prepared the horse probiotics LacFi(TM), consisting of Lactobacillus ruminis KK14, L. equi KK 15, L. reuteri KK18, L. johnsonii KK21, and Bifidobacterium boum HU. Here, we found that the five LacFi(TM) constituent strains remarkably suppressed pro-inflammatory interleukin-17 production in mouse splenocytes stimulated with interleukin-6 and transforming growth factor-β. The protective effects of the probiotic on impaired intestinal barrier function were evaluated in Caco-2 cells treated with tumor necrosis factor-α. Evaluation of transepithelial resistance showed that all the strains exhibited intestinal barrier protective activity, with significant suppression of barrier impairment by L. reuteri KK18. The LacFi(TM) constituent strains were detected in neonatal LacFi(TM)-administered Thoroughbred feces using polymerase chain reaction denaturing gradient gel electrophoresis and culture methods. These five strains were found to be the predominant lactobacilli and bifidobacteria in the intestinal microbiota of LacFi(TM)-administered Thoroughbreds. Administration of LacFi(TM) to neonatal Thoroughbreds decreased diarrhea incidence from 75.9% in the control group (n=29 neonatal Thoroughbreds) to 30.7% in the LacFi(TM)-administered group (n=101 neonatal Thoroughbreds) immediately after birth to 20 weeks after birth. LacFi(TM) treatment also prevented diarrhea especially at and around 4 weeks and from 10 to 16 weeks. The duration of diarrhea was also shorter in the probiotics-administered group (7.4 ± 0.8 days) than in the control group (14.0 ± 3.2 days). These results indicate that the LacFi(TM) probiotics regulates intestinal function and contributes to diarrhea prevention.

  8. Determination of the In Vitro and In Vivo Antimicrobial Activity on Salivary Streptococci and Lactobacilli and Chemical Characterisation of the Phenolic Content of a Plantago lanceolata Infusion

    PubMed Central

    Roberto, Lia; Ingenito, Aniello; Roscetto, Emanuela

    2015-01-01

    Introduction. Plant extracts may be suitable alternative treatments for caries. Aims. To investigate the in vitro and in vivo antimicrobial effects of Plantago lanceolata herbal tea (from flowers and leaves) on cariogenic bacteria and to identify the major constituents of P. lanceolata plant. Materials and Methods. The MIC and MBC against cariogenic bacteria were determined for P. lanceolata tea. Subsequently, a controlled random clinical study was conducted. Group A was instructed to rinse with a P. lanceolata mouth rinse, and Group B received a placebo mouth rinse for seven days. The salivary colonisation by streptococci and lactobacilli was investigated prior to treatment and on the fourth and seventh days. Finally, the P. lanceolata tea was analysed for its polyphenolic content, and major phenolics were identified. Results and Discussion. P. lanceolata teas demonstrate good in vitro antimicrobial activity. The in vivo test showed that Group A subjects presented a significant decrease in streptococci compared to Group B. The phytochemical analysis revealed that flavonoids, coumarins, lipids, cinnamic acids, lignans, and phenolic compounds are present in P. lanceolata infusions. Conclusions. P. lanceolata extract could represent a natural anticariogenic agent via an antimicrobial effect and might be useful as an ancillary measure to control the proliferation of cariogenic flora. PMID:25767805

  9. Probiotic Lactobacillus fermentum UCO-979C biofilm formation on AGS and Caco-2 cells and Helicobacter pylori inhibition.

    PubMed

    Salas-Jara, M J; Sanhueza, E A; Retamal-Díaz, A; González, C; Urrutia, H; García, A

    2016-11-01

    The ability of the human isolate Lactobacillus fermentum UCO-979C to form biofilm and synthesize exopolysaccharide on abiotic and biotic models is described. These properties were compared with the well-known Lactobacillus casei Shirota to better understand their anti-Helicobacter pylori probiotic activities. The two strains of lactobacilli synthesized exopolysaccharide as detected by the Dubois method and formed biofilm on abiotic and biotic surfaces visualized by crystal violet staining and scanning electron microscopy. Concomitantly, these strains inhibited H. pylori urease activity by up to 80.4% (strain UCO-979C) and 66.8% (strain Shirota) in gastric adenocarcinoma (AGS) cells, but the two species showed equal levels of inhibition (~84%) in colorectal adenocarcinoma (Caco-2) cells. The results suggest that L. fermentum UCO-979C has probiotic potential against H. pylori infections. However, further analyses are needed to explain the increased activity observed against the pathogen in AGS cells as compared to L. casei Shirota.

  10. Isolation and characterization of lactobacilli from human faeces and indigenous fermented foods for their potential application as probiotics.

    PubMed

    Mandal, Hemanti; Jariwala, Ruchi; Bagchi, Tamishraha

    2016-04-01

    This study was conducted to select Lactobacillus strains from various sources on the basis of their probiotic attributes, such as acid and bile tolerance, binding to intestinal cells, and antimicrobial activity. Twelve isolates were obtained from human and food sources and were evaluated against standard probiotic Lactobacillus rhamnosus GG (LGG). Isolates were also studied for their antibiotic susceptibility. Isolate Lactobacillus fermentum GPI-6 showed the best survival profile at 0.3% and 1% bile salt, as compared with LGG. Isolates Lactobacillus plantarum GRI-2 and Lactobacillus salivarius GPI-4 showed no reduction in survival rate at pH 2.5. As expected, isolates showed strain-specific differences when comparing various attributes. Isolates GPI-4, GPI-7, and FA-5 showed better adhesion to HT-29, while isolate GPI-4 adhered better to Caco-2 cells than did LGG. However, when studying their ability to compete with Escherichia coli O26:H11, isolates GPI-6 and GPI-7 significantly inhibited E. coli adhesion to both HT-29 and Caco-2 cells compared with LGG. In conclusion, isolates GPI-4, GPI-7, and FA-5 showed excellent binding ability and antagonistic activity and better tolerance to acidic pH (pH 2.5) and to different bile salt concentrations in comparison with LGG, and hence, they could be considered as potential probiotic candidates.

  11. A combination of a dairy product fermented by lactobacilli and galactooligosaccharides shows additive effects on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor.

    PubMed

    Takasugi, Satoshi; Ashida, Kinya; Maruyama, Suyaka; Matsukiyo, Yukari; Kaneko, Tetsuo; Yamaji, Taketo

    2013-06-01

    This study aimed to investigate the effects of a combination of a dairy product fermented by lactobacilli (DFL) and galactooligosaccharides (GOS) on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor (PPI). Three-week-old male rats were assigned to receive one of six diets: a control diet, control diets containing 1.6 or 5.0 % GOS, a DFL diet and DFL diets containing 1.6 or 5.0 % GOS for 9 days. From day 5 of the feeding period, half of the rats fed with control diets were subcutaneously administered with saline, whereas the remaining rats were administered with PPI for 5 days. Calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe) and zinc (Zn) balances were determined from days 6 to 9. PPI administration significantly decreased the apparent absorption of Ca and Fe and increased urinary P excretion, resulting in decreased Ca, Fe and P retention. GOS dose-dependently increased the apparent absorption of Ca, Mg and Fe and urinary Mg excretion and decreased urinary P excretion. DFL significantly increased the apparent absorption of Ca and Mg and urinary Mg excretion. The combination of DFL and GOS additively affected these parameters, resulting in increased Ca, P and Fe retention, and it further increased the apparent absorption and retention of Zn at 5.0 % GOS. In conclusion, the combination of DFL and GOS improves Ca, P and Fe retention in an additive manner and increases the Zn retention in growing rats with hypochlorhydria induced by PPI.

  12. Probiotic cheese containing Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus NCFM® modifies subpopulations of fecal lactobacilli and Clostridium difficile in the elderly.

    PubMed

    Lahtinen, Sampo J; Forssten, Sofia; Aakko, Juhani; Granlund, Linda; Rautonen, Nina; Salminen, Seppo; Viitanen, Matti; Ouwehand, Arthur C

    2012-02-01

    Aging is associated with alterations in the intestinal microbiota and with immunosenescence. Probiotics have the potential to modify a selected part of the intestinal microbiota as well as improve immune functions and may, therefore, be particularly beneficial to elderly consumers. In this randomized, controlled cross-over clinical trial, we assessed the effects of a probiotic cheese containing Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus NCFM on the intestinal microbiota and fecal immune markers of 31 elderly volunteers and compared these effects with the administration of the same cheese without probiotics. The probiotic cheese was found to increase the number of L. rhamnosus and L. acidophilus NCFM in the feces, suggesting the survival of the strains during the gastrointestinal transit. Importantly, probiotic cheese administration was associated with a trend towards lower counts of Clostridium difficile in the elderly, as compared with the run-in period with the plain cheese. The effect was statistically significant in the subpopulation of the elderly who harbored C. difficile at the start of the study. The probiotic cheese was not found to significantly alter the levels of the major microbial groups, suggesting that the microbial changes conferred by the probiotic cheese were limited to specific bacterial groups. Despite that the administration of the probiotic cheese to the study population has earlier been shown to significantly improve the innate immunity of the elders, we did not observe measurable changes in the fecal immune IgA concentrations. No increase in fecal calprotectin and β-defensin concentrations suggests that the probiotic treatment did not affect intestinal inflammatory markers. In conclusion, the administration of probiotic cheese containing L. rhamnosus HN001 and L. acidophilus NCFM, was associated with specific changes in the intestinal microbiota, mainly affecting specific subpopulations of intestinal lactobacilli and C

  13. Radiation resistance of lactobacilli isolated from radurized meat relative to growth and environment. [Lactobacillus sake; Lactobacillus curvatus; Lactobacillus farciminis; Staphylococcus aureus; Salmonella typimurium

    SciTech Connect

    Hastings, J.W.; Holzapfel, W.H.; Niemand, J.G.

    1986-10-01

    Of 113 lactobacilli isolated from radurized (5 kGy) minced meat, 7 Lactobacillus sake strains, 1 L. curvatus strain, and 1 L. farciminis strain were used for radiation resistance studies in a semisynthetic substrate (i.e., modified MRS broth). Five reference Lactobacillus spp. one Staphylococcus aureus strain, and one Salmonella typhimurium strain were used for comparative purposes. All L. sake isolates exhibited the phenomenon of being more resistant to gamma-irradiation in the exponential (log) phase than in the stationary phase of their growth cycles by a factor of 28%. Four reference strains also exhibited this phenomenon, with L. sake (DSM 20017) showing a 68% increase in resistance in the log phase over the stationary phase. This phenomenon was not common to all bacteria tested and is not common to all strains with high radiation resistance. Four L. sake isolates and three reference strains were used in radiation sensitivity testing in a natural food system (i.e., meat). The bacteria were irradiated in minced meat and packaged under four different conditions (air, vacuum, CO/sub 2/, and N/sub 2/). Organisms exhibited the highest death rate (lowest D/sub 10/ values (doses required to reduce the logarithm of the bacterial population by 1) under CO/sub 2/ packaging conditions, but resistance to irradiation was increased under N/sub 2/. The D/sup 10/ values of the isolates were generally greater than those of the reference strains. The D/sup 10/ values were also higher (approximately two times) in meat than in a semisynthetic growth medium.

  14. High dose and low dose Lactobacilli acidophilus exerted differential immune modulating effects on T cell immune responses induced by an oral human rotavirus vaccine in gnotobiotic pigs

    PubMed Central

    Wen, Ke; Li, Guohua; Bui, Tammy; Liu, Fangning; Li, Yanru; Kocher, Jacob; Lin, Lin; Yang, Xingdong; Yuan, Lijuan

    2011-01-01

    Background Strain-specific effects of probiotics in pro- or anti-inflammatory immune responses have been well recognized. Several proinflammatory Lactobacillus strains have been shown to act as adjuvants to enhance the immunogenicity of vaccines. However, dose effects of probiotics in modulating immune responses are not clearly understood. This study examined the dose effects of Lactobacillus acidophilus (LA) NCFM strain on T cell immune responses to rotavirus vaccination in a gnotobiotic (Gn) pig model. Methods Frequencies of IFN-γ producing CD4+ and CD8+ T cell and IL-10 and TGF-β producing CD4+CD25+ and CD4+CD25- regulatory T (Treg) cell responses were determined in the intestinal and systemic lymphoid tissues of Gn pigs vaccinated with an oral human rotavirus vaccine in conjunction with low dose (5 feedings; up to 106 colony forming units [CFU]/dose) or high dose (14 feedings; up to 109 CFU/dose) or without LA feeding. Results Low dose LA significantly promoted IFN-γ producing T cell responses and down-regulated Treg cell responses and their TGF-β and IL-10 productions in all the tissues compared to the high dose LA and control groups. To the contrary, high dose LA increased the frequencies of Treg cells in most of the tissues compared to the control groups. The dose effects of LA on IFN-γ producing T cell and CD4+CD25- Treg cell immune responses were similar in the intestinal and systemic lymphoid tissues and were independent from the vaccination. Conclusion Thus the same probiotic strain in different doses can either promote or suppress IFN-γ producing T cell or Treg cell immune responses. These findings have significant implications in the use of probiotic lactobacilli as immunostimulatory versus immunoregulatory agents. Probiotics can be ineffective or even detrimental if not used at the optimal dosage for the appropriate purposes. PMID:22178726

  15. Systemic Effects of Ingested Lactobacillus Rhamnosus: Inhibition of Mast Cell Membrane Potassium (IKCa) Current and Degranulation

    PubMed Central

    Forsythe, Paul; Wang, Binxiang; Khambati, Ibrahim; Kunze, Wolfgang A.

    2012-01-01

    Exposure of the intestine to certain strains lactobacillus can have systemic immune effects that include the attenuation of allergic responses. Despite the central role of mast cells in allergic disease little is known about the effect of lactobacilli on the function of these cells. To address this we assessed changes in rat mast cell activation following oral treatment with a strain of Lactobacillus known to attenuate allergic responses in animal models. Sprague Dawley rats were fed with L.rhamnosus JB-1 (1×109) or vehicle control for 9 days. Mediator release from peritoneal mast cells (RPMC) was determined in response to a range of stimuli. Passive cutaneous anaphylaxis (PCA) was used to assess mast cell responses in vivo. The Ca2+ activated K+ channel (KCa3.1) current, identified as critical to mast cell degranulation, was monitored by whole cell patch-clamp. L.rhamnosus JB-1 treatment lead to significant inhibition of mast cell mediator release in response to a range of stimuli including IgE mediated activation. Furthermore, the PCA response was significantly reduced in treated rats. Patch-clamp studies revealed that RPMC from treated animals were much less responsive to the KCa3.1 opener, DCEBIO. These studies demonstrate that Ingestion of L.rhamnosus JB-1 leads to mast cell stabilization in rats and identify KCa3.1 as an immunomodulatory target for certain lactobacilli. Thus the systemic effects of certain candidate probiotics may include mast cell stabilization and such actions could contribute to the beneficial effect of these organisms in allergic and other inflammatory disorders. PMID:22815978

  16. Sourdough lactobacilli and celiac disease.

    PubMed

    Gobbetti, Marco; Giuseppe Rizzello, Carlo; Di Cagno, Raffaella; De Angelis, Maria

    2007-04-01

    Celiac disease (CD) is one of the most common food intolerance. The only effective treatment for CD is a strict adherence to a gluten-free diet throughout the patient's lifetime. Gluten-free products are not widely available and are usually more expensive than their gluten-containing counterparts. There is, therefore, an urgent need to develop safe and effective therapeutic alternatives, to develop high-quality gluten-free products and to investigate the potential of the bread making biotechnology following ancient protocols which include long-time fermentation by selected sourdough lactic acid bacteria. This review describes the most relevant results related to biotechnologies that use selected sourdough lactic acid bacteria and probiotics as starters for sourdough fermentation to investigate their potential to decrease the risk of gluten contamination in gluten-free products. As shown by studies in vitro on celiac intestinal tissue and in vivo on CD patients, the bacterial proteolytic activity is rather promising not only as currently demonstrated for eliminating traces of contaminant gluten but probably also in perspective for the manufacture of tolerated baked goods.

  17. The Natural Antimicrobial Peptide Subtilosin Acts Synergistically with Glycerol Monolaurate, Lauric Arginate, and ε-Poly-l-Lysine against Bacterial Vaginosis-Associated Pathogens but Not Human Lactobacilli

    PubMed Central

    Sutyak Noll, Katia; Prichard, Mark N.; Khaykin, Arkady; Sinko, Patrick J.

    2012-01-01

    Subtilosin is a cyclical antimicrobial peptide produced by Bacillus amyloliquefaciens that has antimicrobial activity against the bacterial vaginosis-associated human pathogen Gardnerella vaginalis. The ability of subtilosin to inhibit G. vaginalis alone and in combination with the natural antimicrobial agents glycerol monolaurate (Lauricidin), lauric arginate, and ε-poly-l-lysine was tested using a checkerboard approach. Subtilosin was found to act synergistically with all of the chosen antimicrobials. These promising results indicate that lower concentrations of subtilosin in combination with other compounds could effectively be used to inhibit growth of the pathogen, thereby decreasing the risk of developed antimicrobial resistance. This is the first report on the effects of subtilosin combined with other natural antimicrobials against G. vaginalis. PMID:22252803

  18. The natural antimicrobial peptide subtilosin acts synergistically with glycerol monolaurate, lauric arginate, and ε-poly-L-lysine against bacterial vaginosis-associated pathogens but not human lactobacilli.

    PubMed

    Noll, Katia Sutyak; Prichard, Mark N; Khaykin, Arkady; Sinko, Patrick J; Chikindas, Michael L

    2012-04-01

    Subtilosin is a cyclical antimicrobial peptide produced by Bacillus amyloliquefaciens that has antimicrobial activity against the bacterial vaginosis-associated human pathogen Gardnerella vaginalis. The ability of subtilosin to inhibit G. vaginalis alone and in combination with the natural antimicrobial agents glycerol monolaurate (Lauricidin), lauric arginate, and ε-poly-L-lysine was tested using a checkerboard approach. Subtilosin was found to act synergistically with all of the chosen antimicrobials. These promising results indicate that lower concentrations of subtilosin in combination with other compounds could effectively be used to inhibit growth of the pathogen, thereby decreasing the risk of developed antimicrobial resistance. This is the first report on the effects of subtilosin combined with other natural antimicrobials against G. vaginalis.

  19. Saccadic Inhibition in Reading

    ERIC Educational Resources Information Center

    Reingold, Eyal M.; Stampe, Dave M.

    2004-01-01

    In 5 experiments, participants read text that was briefly replaced by a transient image for 33 ms at random intervals. A decrease in saccadic frequency, referred to as saccadic inhibition, occurred as early as 60-70 ms following the onset of abrupt changes in visual input. It was demonstrated that the saccadic inhibition was influenced by the…

  20. Lectin-Like Molecules of Lactobacillus rhamnosus GG Inhibit Pathogenic Escherichia coli and Salmonella Biofilm Formation

    PubMed Central

    Petrova, Mariya I.; Imholz, Nicole C. E.; Verhoeven, Tine L. A.; Balzarini, Jan; Van Damme, Els J. M.; Schols, Dominique; Vanderleyden, Jos; Lebeer, Sarah

    2016-01-01

    Objectives Increased antibiotic resistance has catalyzed the research on new antibacterial molecules and alternative strategies, such as the application of beneficial bacteria. Since lectin molecules have unique sugar-recognizing capacities, and pathogens are often decorated with sugars that affect their survival and infectivity, we explored whether lectins from the probiotic strain Lactobacillus rhamnosus GG have antipathogenic properties. Methods The genome sequence of L. rhamnosus GG was screened for the presence of lectin-like proteins. Two genes, LGG_RS02780 and LGG_RS02750, encoding for polypeptides with an N-terminal conserved L-type lectin domain were detected and designated Llp1 (lectin-like protein 1) and Llp2. The capacity of Llp1 and Llp2 to inhibit biofilm formation of various pathogens was investigated. Sugar specificity was determined by Sepharose beads assays and glycan array screening. Results The isolated lectin domains of Llp1 and Llp2 possess pronounced inhibitory activity against biofilm formation by various pathogens, including clinical Salmonella species and uropathogenic E. coli, with Llp2 being more active than Llp1. In addition, sugar binding assays with Llp1 and Llp2 indicate specificity for complex glycans. Both proteins are also involved in the adhesion capacity of L. rhamnosus GG to gastrointestinal and vaginal epithelial cells. Conclusions Lectins isolated from or expressed by beneficial lactobacilli could be considered promising bio-active ingredients for improved prophylaxis of urogenital and gastrointestinal infections. PMID:27537843

  1. Synbiotic Lactobacillus acidophilus NCFM and cellobiose does not affect human gut bacterial diversity but increases abundance of lactobacilli, bifidobacteria and branched-chain fatty acids: a randomized, double-blinded cross-over trial.

    PubMed

    van Zanten, Gabriella C; Krych, Lukasz; Röytiö, Henna; Forssten, Sofia; Lahtinen, Sampo J; Abu Al-Soud, Waleed; Sørensen, Søren; Svensson, Birte; Jespersen, Lene; Jakobsen, Mogens

    2014-10-01

    Probiotics, prebiotics, and combinations thereof, that is synbiotics, have been reported to modulate gut microbiota of humans. In this study, effects of a novel synbiotic on the composition and metabolic activity of human gut microbiota were investigated. Healthy volunteers (n = 18) were enrolled in a double-blinded, randomized, and placebo-controlled cross-over study and received synbiotic [Lactobacillus acidophilus NCFM (10(9) CFU) and cellobiose (5 g)] or placebo daily for 3 weeks. Fecal samples were collected and lactobacilli numbers were quantified by qPCR. Furthermore, 454 tag-encoded amplicon pyrosequencing was used to monitor the effect of synbiotic on the composition of the microbiota. The synbiotic increased levels of Lactobacillus spp. and relative abundances of the genera Bifidobacterium, Collinsella, and Eubacterium while the genus Dialister was decreased (P < 0.05). No other effects were found on microbiota composition. Remarkably, however, the synbiotic increased concentrations of branched-chain fatty acids, measured by gas chromatography, while short-chain fatty acids were not affected.

  2. Inhibition of selectin binding

    DOEpatents

    Nagy, Jon O.; Spevak, Wayne R.; Dasgupta, Falguni; Bertozzi, Carolyn

    1999-10-05

    This invention provides a system for inhibiting the binding between two cells, one expressing P- or L-selectin on the surface and the other expressing the corresponding ligand. A covalently crosslinked lipid composition is prepared having saccharides and acidic group on separate lipids. The composition is then interposed between the cells so as to inhibit binding. Inhibition can be achieved at an effective oligosaccharide concentration as low as 10.sup.6 fold below that of the free saccharide. Since selectins are involved in recruiting cells to sites of injury, this system can be used to palliate certain inflammatory and immunological conditions.

  3. Inhibition of selectin binding

    DOEpatents

    Nagy, Jon O.; Spevak, Wayne R.; Dasgupta, Falguni; Bertozzi, Caroline

    2001-10-09

    This invention provides compositions for inhibiting the binding between two cells, one expressing P- or L-selectin on the surface and the other expressing the corresponding ligand. A covalently crosslinked lipid composition is prepared having saccharides and acidic group on separate lipids. The composition is then interposed between the cells so as to inhibit binding. Inhibition can be achieved at an effective oligosaccharide concentration as low as 10.sup.6 fold below that of the free saccharide. Since selectins are involved in recruiting cells to sites of injury, these composition scan be used to palliate certain inflammatory and immunological conditions.

  4. Inhibition of selectin binding

    DOEpatents

    Nagy, Jon O.; Spevak, Wayne R.; Dasgupta, Falguni; Bertozzi, Caroline

    1999-01-01

    This invention provides compositions for inhibiting the binding between two cells, one expressing P- or L-selectin on the surface and the other expressing the corresponding ligand. A covalently crosslinked lipid composition is prepared having saccharides and acidic group on separate lipids. The composition is then interposed between the cells so as to inhibit binding. Inhibition can be achieved at an effective oligosaccharide concentration as low as 10.sup.6 fold below that of the free saccharide. Since selectins are involved in recruiting cells to sites of injury, these composition scan be used to palliate certain inflammatory and immunological conditions.

  5. Potentiation of latent inhibition.

    PubMed

    Rodriguez, Gabriel; Hall, Geoffrey

    2008-07-01

    Rats were given exposure either to an odor (almond) or a compound of odor plus taste (almond plus saline), prior to training in which the odor served as the conditioned stimulus. It was found, for both appetitive and aversive procedures, that conditioning was retarded by preexposure (a latent inhibition effect), and the extent of the retardation was greater in rats preexposed to the compound (i.e., latent inhibition to the odor was potentiated by the presence of the taste). In contrast, the presence of the taste during conditioning itself overshadowed learning about the odor. We argue that the presence of the salient taste in compound with the odor enhances the rate of associative learning, producing a rapid loss in the associability of the odor. This loss of associability will generate both overshadowing and the potentiation of latent inhibition that is observed after preexposure to the compound.

  6. Chitin deacetylase product inhibition.

    PubMed

    Jaworska, Malgorzata M

    2011-02-01

    Chitin deacetylase is the only known enzyme catalyzing the hydrolysis of the acetamino linkage in the N-acetylglucosamine units of chitin and chitosan. This reaction can play an important role in enzymatic production of chitosan from chitin, or in enzymatic modification of chitosan, which has applications in medicine, pharmacy or plant protection. It was previously shown that acetic acid, a product of the deacetylation process, may act as an inhibitor of chitin deacetylase. Here we show the mechanism of inhibition of chitin deacetylase isolated from Absidia orchidis vel coerulea by acetic acid released during the deacetylation process. The process follows competitive inhibition with respect to acetic acid with an inhibition constant of K(i) = 0.286 mmol/L. These results will help to find the optimal system to carry out the enzymatic deacetylation process for industrial applications.

  7. Novel approaches for the taxonomic and metabolic characterization of lactobacilli: Integration of 16S rRNA gene sequencing with MALDI-TOF MS and 1H-NMR

    PubMed Central

    Parolin, Carola; Giordani, Barbara; Compri, Monica; Cevenini, Roberto; Vitali, Beatrice

    2017-01-01

    Lactobacilli represent a wide range of bacterial species with several implications for the human host. They play a crucial role in maintaining the ecological equilibrium of different biological niches and are essential for fermented food production and probiotic formulation. Despite the consensus about the ‘health-promoting’ significance of Lactobacillus genus, its genotypic and phenotypic characterization still poses several difficulties. The aim of this study was to assess the integration of different approaches, genotypic (16S rRNA gene sequencing), proteomic (MALDI-TOF MS) and metabolomic (1H-NMR), for the taxonomic and metabolic characterization of Lactobacillus species. For this purpose we analyzed 40 strains of various origin (intestinal, vaginal, food, probiotics), belonging to different species. The high discriminatory power of MALDI-TOF for species identification was underlined by the excellent agreement with the genotypic analysis. Indeed, MALDI-TOF allowed to correctly identify 39 out of 40 Lactobacillus strains at the species level, with an overall concordance of 97.5%. In the perspective to simplify the MALDI TOF sample preparation, especially for routine practice, we demonstrated the perfect agreement of the colony-picking from agar plates with the protein extraction protocol. 1H-NMR analysis, applied to both culture supernatants and bacterial lysates, identified a panel of metabolites whose variations in concentration were associated with the taxonomy, but also revealed a high intra-species variability that did not allow a species-level identification. Therefore, despite not suitable for mere taxonomic purposes, metabolomics can be useful to correlate particular biological activities with taxonomy and to understand the mechanisms related to the antimicrobial effect shown by some Lactobacillus species. PMID:28207855

  8. Survival and in vivo adhesion of human isolates Lactobacillus gasseri LF221 and K7 in weaned piglets and their effects on coliforms, clostridia and lactobacilli viable counts in faeces and mucosa.

    PubMed

    Matijasic, Bojana Bogovic; Stojkovic, Sasa; Rogelj, Irena

    2006-11-01

    In in vivo study on 24 weaned piglets (8 per group), the survival rates of human isolates Lactobacillus gasseri K7 and LF221 were quantified by selective enumeration on MRS agar with rifampicin, and the presence of both strains in intestinal mucosa was examined. Faeces from individual animals were analysed for the number (cfu/g) of coliforms, lactobacilli, clostridia and both of the two probiotic strains during 2-weeks probiotic application period (5 x 10(10) cfu of individual strain/day) and 1 week after the probiotic treatment was ceased. Samples of duodenum, jejunum and ileum of sacrificed animals (5th or 20th day) were also examined microbiologically. A great variability in the microflora of faeces and mucosa was observed even between equally treated animals. The survival of both Lb. gasseri strains was established by their detection in the faeces (2.5 x 10(5) to 3.3 x 10(5) cfu of K7 strain/g faeces; 4.5 x 10(5) to 5 x 10(5) cfu of LF221 strain/g). In two animals, the LF221 or K7 viable cells were found in the faeces 6 d after ceasing probiotic application. In both animals from the group fed with Lb. gasseri K7 that were sacrificed 5 d after weaning, the presence of K7 strain was found either in the mucosa of duodenum (140 cfu/10 cm2) and jejunum (170 cfu/10 cm2) or in the ileum (1600 cfu/10 cm2). LF221 cells were detected in the ileal mucosa of one piglet (820 cfu/10 cm2). The results demonstrated the capability of both tested strains of in vivo adhesion to intestinal mucosa and of temporary colonisation of the piglets' intestine.

  9. [Non-viral sexually transmitted infections - Epidemiology, clinical manifestations, diagnostics and therapy : Part 1: Gonococci].

    PubMed

    Nenoff, P; Manos, A; Ehrhard, I; Krüger, C; Paasch, U; Helmbold, P; Handrick, W

    2017-01-01

    Approximately 1 million people are infected per day worldwide by one or more sexually transmitted infections (STI) as estimated by the World Health Organization (WHO). Gonorrhoea represents an almost exclusively sexually transmitted infection, which predominantly affects mucous membranes of the genitourinary tract. Extragenital localization of infections is also possible, e. g. in the anorectal region. Currently, only syphilis and human immunodeficiency virus (HIV) are notifiable diseases according to the Infection Protection Act in Germany. In Saxony, an extended registration ordinance according to the German Infection Protection Act is in force, which means that besides syphilis the laboratory detection of Neisseria gonorrhoeae, Chlamydia trachomatis and genital mycoplasms are also notifiable infections. In particular, beginning in 2009 in Saxony a spectacular increase of registered infections due to N. gonorrhoeae was observed and in 2015 altogether 824 infections due to N. gonorrhoeae were reported. Alarming is the increase in resistance of N. gonorrhoeae against penicillin, doxycycline, ciprofloxacin and recently also against azithromycin and third generation cephalosporins. The so-called superbug of N. gonorrhoeae, which originated in Japan with multidrug resistance against most of the currently available oral antibiotics, has now arrived in Europe. Intramuscular or intravenous injection of ceftriaxone plus oral azithromycin, each given as single dose is the standard therapy for gonorrhoea.

  10. Peptide bioregulators inhibit apoptosis.

    PubMed

    Khavinson, V K; Kvetnoii, I M

    2000-12-01

    The effects of peptide bioregulators epithalon and vilon on the dynamics of irradiation-induced apoptotic death of spleen lymphocytes in rats indicate that these agents inhibit physiologically programmed cell death. The antiapoptotic effect of vilon was more pronounced, which corroborates the concept on tissue-specific effect of peptide bioregulators.

  11. Serine proteases inhibiting cyanopeptides.

    PubMed

    Radau, G

    2000-08-01

    There are many compounds inhibiting serine proteases which play an important role in the human organism. This article reviews publications on the low-molecular weight, serine protease inhibitory cyanopeptides and reports on new developments in establishing structure-activity relationships.

  12. Reinforcement of inhibition

    PubMed Central

    Anger, Douglas

    1983-01-01

    A differential-reinforcement-of-other-behavior (DRO) schedule with trials and delayed reinforcement was investigated. Periodically a wheel was briefly available to rats, followed six seconds later by brief availability of a bar. Variable-ratio food reinforcement of wheel turns was adjusted to give 95% turns. After variable-ratio-five reinforcement of bar presses produced 100% pressing, then separate ratio schedules were used for presses following turns (turn presses) and presses following nonturns (nonturn presses). Increasing nonturn-press reinforcements decreased turns, even though total reinforcements increased. Reversal by decreasing nonturn-press reinforcements raised turns, though with hysteresis. Thus food reinforcement increased nonturns even though delayed six to ten seconds after nonturns, a delay that greatly reduces response reinforcement. Those and other results indicate that the turn decrease was not due to reinforcement of competing responses. Evidence against other alternatives, and the reduction of responding by increased reinforcement, indicate that the term inhibition is appropriate for the phenomenon reinforced. Response-specific inhibition appears appropriate for this particular kind, since its effects are more specific to particular responses than Pavlovian conditioned-inhibition. Response-specific inhibition seems best considered a behavioral output comparable to responses (e.g., both reinforcible) but with important properties different from responses (e.g., different reinforcement-delay gradients). PMID:16812315

  13. Semantic processing and response inhibition.

    PubMed

    Chiang, Hsueh-Sheng; Motes, Michael A; Mudar, Raksha A; Rao, Neena K; Mansinghani, Sethesh; Brier, Matthew R; Maguire, Mandy J; Kraut, Michael A; Hart, John

    2013-11-13

    The present study examined functional MRI (fMRI) BOLD signal changes in response to object categorization during response selection and inhibition. Young adults (N=16) completed a Go/NoGo task with varying object categorization requirements while fMRI data were recorded. Response inhibition elicited increased signal change in various brain regions, including medial frontal areas, compared with response selection. BOLD signal in an area within the right angular gyrus was increased when higher-order categorization was mandated. In addition, signal change during response inhibition varied with categorization requirements in the left inferior temporal gyrus (lIT). lIT-mediated response inhibition when inhibiting the response only required lower-order categorization, but lIT mediated both response selection and inhibition when selecting and inhibiting the response required higher-order categorization. The findings characterized mechanisms mediating response inhibition associated with semantic object categorization in the 'what' visual object memory system.

  14. Pharmacological inhibition of FTO.

    PubMed

    McMurray, Fiona; Demetriades, Marina; Aik, WeiShen; Merkestein, Myrte; Kramer, Holger; Andrew, Daniel S; Scudamore, Cheryl L; Hough, Tertius A; Wells, Sara; Ashcroft, Frances M; McDonough, Michael A; Schofield, Christopher J; Cox, Roger D

    2015-01-01

    In 2007, a genome wide association study identified a SNP in intron one of the gene encoding human FTO that was associated with increased body mass index. Homozygous risk allele carriers are on average three kg heavier than those homozygous for the protective allele. FTO is a DNA/RNA demethylase, however, how this function affects body weight, if at all, is unknown. Here we aimed to pharmacologically inhibit FTO to examine the effect of its demethylase function in vitro and in vivo as a first step in evaluating the therapeutic potential of FTO. We showed that IOX3, a known inhibitor of the HIF prolyl hydroxylases, decreased protein expression of FTO (in C2C12 cells) and reduced maximal respiration rate in vitro. However, FTO protein levels were not significantly altered by treatment of mice with IOX3 at 60 mg/kg every two days. This treatment did not affect body weight, or RER, but did significantly reduce bone mineral density and content and alter adipose tissue distribution. Future compounds designed to selectively inhibit FTO's demethylase activity could be therapeutically useful for the treatment of obesity.

  15. Pharmacological Inhibition of FTO

    PubMed Central

    McMurray, Fiona; Demetriades, Marina; Aik, WeiShen; Merkestein, Myrte; Kramer, Holger; Andrew, Daniel S.; Scudamore, Cheryl L.; Hough, Tertius A.; Wells, Sara; Ashcroft, Frances M.; McDonough, Michael A.; Schofield, Christopher J.; Cox, Roger D.

    2015-01-01

    In 2007, a genome wide association study identified a SNP in intron one of the gene encoding human FTO that was associated with increased body mass index. Homozygous risk allele carriers are on average three kg heavier than those homozygous for the protective allele. FTO is a DNA/RNA demethylase, however, how this function affects body weight, if at all, is unknown. Here we aimed to pharmacologically inhibit FTO to examine the effect of its demethylase function in vitro and in vivo as a first step in evaluating the therapeutic potential of FTO. We showed that IOX3, a known inhibitor of the HIF prolyl hydroxylases, decreased protein expression of FTO (in C2C12 cells) and reduced maximal respiration rate in vitro. However, FTO protein levels were not significantly altered by treatment of mice with IOX3 at 60 mg/kg every two days. This treatment did not affect body weight, or RER, but did significantly reduce bone mineral density and content and alter adipose tissue distribution. Future compounds designed to selectively inhibit FTO’s demethylase activity could be therapeutically useful for the treatment of obesity. PMID:25830347

  16. Biodiversity of spoilage lactobacilli: phenotypic characterisation.

    PubMed

    Sanders, J W; Oomes, S J C M; Membré, J-M; Wegkamp, A; Wels, M

    2015-02-01

    Preventing food spoilage is a challenge for the food industry, especially when applying mild preservation methods and when avoiding the use of preservatives. Therefore, it is essential to explore the boundaries of preservation by better understanding the causative microbes, their phenotypic behaviour and their genetic makeup. Traditionally in food microbiology, single strains or small sets of selected strains are studied. Here a collection of 120 strains of 6 different spoilage related Lactobacillus species and a multitude of sources was prepared and their growth characteristics determined in 384-well plates by optical density measurements (OD) over 20 days, for 20 carbon source-related phenotypic parameters and 25 preservation-related phenotypic parameters. Growth under all conditions was highly strain specific and there was no correlation of phenotypes at the species level. On average Lactobacillus brevis strains were amongst the most robust whereas Lactobacillus fructivorans strains had a much narrower growth range. The biodiversity data allowed the definition of preservation boundaries on the basis of the number of Lactobacillus strains that reached a threshold OD, which is different from current methods that are based on growth ability or growth rate of a few selected strains. Genetic information on these microbes and a correlation study will improve the mechanistic understanding of preservation resistance and this will support the future development of superior screening and preservation methods.

  17. Firefly luciferase inhibition.

    PubMed

    Leitão, João M M; Esteves da Silva, Joaquim C G

    2010-10-05

    Firefly luciferase (Luc) is the most studied of the luciferase enzymes and the mechanism and kinetics of the reactions catalyzed by this enzyme have been relatively well characterized. Luc catalyzes the bioluminescent reaction involving firefly luciferin (D-LH(2)), adenosine triphosphate (ATP), magnesium ion and molecular oxygen with the formation of an electronically excited species (oxyluciferin), inorganic pyrophosphate (PPi), carbon dioxide and adenosine monophosphate (AMP). Luc also catalyzes other non-luminescent reactions, which can interfere with the light production mechanism. Following electronic relaxation, the excited oxyluciferin emits radiation in the visible region of the electromagnetic spectrum (550-570 nm). Among the various possible compounds, several classes of inhibitory substances interfere with the activity of this enzyme: here, we consider substrate-related compounds, intermediates or products of the Luc catalyzed reactions, in addition to anesthetics and, fatty acids. This review summarizes the main inhibitors of Luc and the corresponding inhibition kinetic parameters.

  18. Anxiety and retrieval inhibition: support for an enhanced inhibition account.

    PubMed

    Nuñez, Mia; Gregory, Josh; Zinbarg, Richard E

    2017-02-01

    Retrieval inhibition of negative associations is important for exposure therapy for anxiety, but the relationship between memory inhibition and anxiety is not well understood-anxiety could either be associated with enhanced or deficient inhibition. The present study tested these two competing hypotheses by measuring retrieval inhibition of negative stimuli by related neutral stimuli. Non-clinically anxious undergraduates completed measures of trait and state anxiety and completed a retrieval induced forgetting task. Adaptive forgetting varied with state anxiety. Low levels of state anxiety were associated with no evidence for retrieval inhibition for either threatening or non-threatening categories. Participants in the middle tertile of state anxiety scores exhibited retrieval inhibition for non-threatening categories but not for threatening categories. Participants in the highest tertile of state anxiety, however, exhibited retrieval inhibition for both threatening and non-threatening categories with the magnitude of retrieval inhibition being greater for threatening than non-threatening categories. The data are in line with the avoidance aspect of the vigilance-avoidance theory of anxiety and inhibition. Implications for cognitive behavioural therapy practices are discussed.

  19. Inhibition of cellulases by phenols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The inhibition of enzymes by the end products that they make is a well-known phenomenon. Another form of inhibition is manifested by the decrease in hydrolysis of pretreated cellulosic material as the concentration of solid biomass material increases, even though the ratio of enzyme to cellulose is...

  20. Can Arousal Modulate Response Inhibition?

    ERIC Educational Resources Information Center

    Weinbach, Noam; Kalanthroff, Eyal; Avnit, Amir; Henik, Avishai

    2015-01-01

    The goal of the present study was to examine if and how arousal can modulate response inhibition. Two competing hypotheses can be drawn from previous literature. One holds that alerting cues that elevate arousal should result in an impulsive response and therefore impair response inhibition. The other suggests that alerting enhances processing of…

  1. Forcing contact inhibition of locomotion.

    PubMed

    Roycroft, Alice; Mayor, Roberto

    2015-07-01

    Contact inhibition of locomotion drives a variety of biological phenomenon, from cell dispersion to collective cell migration and cancer invasion. New imaging techniques have allowed contact inhibition of locomotion to be visualised in vivo for the first time, helping to elucidate some of the molecules and forces involved in this phenomenon.

  2. Balanced feedforward inhibition and dominant recurrent inhibition in olfactory cortex

    PubMed Central

    Large, Adam M.; Vogler, Nathan W.; Mielo, Samantha; Oswald, Anne-Marie M.

    2016-01-01

    Throughout the brain, the recruitment of feedforward and recurrent inhibition shapes neural responses. However, disentangling the relative contributions of these often-overlapping cortical circuits is challenging. The piriform cortex provides an ideal system to address this issue because the interneurons responsible for feedforward and recurrent inhibition are anatomically segregated in layer (L) 1 and L2/3 respectively. Here we use a combination of optical and electrical activation of interneurons to profile the inhibitory input received by three classes of principal excitatory neuron in the anterior piriform cortex. In all classes, we find that L1 interneurons provide weaker inhibition than L2/3 interneurons. Nonetheless, feedforward inhibitory strength covaries with the amount of afferent excitation received by each class of principal neuron. In contrast, intracortical stimulation of L2/3 evokes strong inhibition that dominates recurrent excitation in all classes. Finally, we find that the relative contributions of feedforward and recurrent pathways differ between principal neuron classes. Specifically, L2 neurons receive more reliable afferent drive and less overall inhibition than L3 neurons. Alternatively, L3 neurons receive substantially more intracortical inhibition. These three features—balanced afferent drive, dominant recurrent inhibition, and differential recruitment by afferent vs. intracortical circuits, dependent on cell class—suggest mechanisms for olfactory processing that may extend to other sensory cortices. PMID:26858458

  3. Biology of TACE inhibition

    PubMed Central

    Newton, R; Solomon, K; Covington, M; Decicco, C; Haley, P; Friedman, S; Vaddi, K

    2001-01-01

    Studies conducted over the past decade have demonstrated a central role for tumour necrosis factor α (TNFα) in inflammatory diseases. As a result of this work, a number of biological agents that neutralise the activity of this cytokine have entered the clinic. The recent clinical data obtained with etanercept and infliximab highlight the relevance of this strategy. TNFα converting enzyme (TACE) is the metalloproteinase that processes the 26 kDa membrane bound precursor of TNFα (proTNFα) to the 17 kDa soluble component. Although a number of proteases have been shown to process proTNFα, none do so with the efficiency of TACE. A series of orally bioavailable, selective, and potent TACE inhibitors are currently in clinical development. These inhibitors effectively block TACE mediated processing of proTNFα and can reduce TNF production by lipopolysaccharide stimulated whole blood by >95%. Through a series of studies it is shown here that >80% of the unprocessed proTNFα is degraded intracellularly. The remainder appears to be transiently expressed on the cell surface. Although, in vitro, TACE inhibition has also been implicated in shedding of p55 and p75 surface TNFα receptors, the in vivo data cast doubt on the consequences of this finding. In a mouse model of collagen-induced arthritis, the inhibitors are efficacious both prophylactically and therapeutically. The efficacy seen is equivalent to strategies that neutralise TNFα. In many studies greater efficacy is observed with the TACE inhibitors, presumably owing to greater penetration to the site of TNFα production.

 PMID:11890648

  4. Catalase is inhibited by flavonoids.

    PubMed

    Krych, Justyna; Gebicka, Lidia

    2013-07-01

    Catalases, heme enzymes, which catalyze decomposition of hydrogen peroxide to water and molecular oxygen, belong to the antioxidant defense system of the cell. In this work we have shown that catalase from bovine liver is inhibited by flavonoids. The inhibition is, at least partially, due to the formation of hydrogen bonds between catalase and flavonoids. In the presence of some flavonoids the formation of unreactive catalase compound II has been detected. The most potent catalase inhibitors among the tested flavonoids have appeared myricetin, epicatechin gallate and epigallocatechin gallate. The relationship between the degree of enzyme inhibition and molecular structure of flavonoids has been analyzed.

  5. A highly acid-resistant novel strain of Lactobacillus johnsonii No. 1088 has antibacterial activity, including that against Helicobacter pylori, and inhibits gastrin-mediated acid production in mice

    PubMed Central

    Aiba, Yuji; Nakano, Yasuhiro; Koga, Yasuhiro; Takahashi, Kenji; Komatsu, Yasuhiko

    2015-01-01

    A novel strain of Lactobacillus johnsonii No. 1088 was isolated from the gastric juice of a healthy Japanese male volunteer, and characterized for its effectiveness in the stomach environment. Lactobacillus johnsonii No. 1088 was found to have the strongest acid resistance among several lactobacilli examined (>10% of cells survived at pH 1.0 after 2 h), and such a high acid resistance property was a specific characteristic of this strain of L. johnsonii. When cultured with various virulent bacteria, L. johnsonii No. 1088 inhibited the growth of Helicobacter pylori,Escherichia coli O-157, Salmonella Typhimurium, and Clostridium difficile, in which case its effectiveness was more potent than that of a type strain of L. johnsonii,JCM2012. In addition to its effect in vitro, L. johnsonii No. 1088 inhibited the growth of H. pylori in human intestinal microbiota-associated mice in both its live and lyophilized forms. Moreover, L. johnsonii No. 1088 suppressed gastric acid secretion in mice via decreasing the number of gastrin-positive cells in the stomach. These results taken together suggest that L. johnsonii No. 1088 is a unique lactobacillus having properties beneficial for supporting H. pylori eradication by triple therapy including the use of a proton pump inhibitor (PPI) and also for prophylaxis of gastroesophageal reflux disease possibly caused after H. pylori eradication as a side effect of PPI. PMID:25771812

  6. Infrared inhibition of embryonic hearts

    NASA Astrophysics Data System (ADS)

    Wang, Yves T.; Rollins, Andrew M.; Jenkins, Michael W.

    2016-06-01

    Infrared control is a new technique that uses pulsed infrared lasers to thermally alter electrical activity. Originally developed for nerves, we have applied this technology to embryonic hearts using a quail model, previously demonstrating infrared stimulation and, here, infrared inhibition. Infrared inhibition enables repeatable and reversible block, stopping cardiac contractions for several seconds. Normal beating resumes after the laser is turned off. The block can be spatially specific, affecting propagation on the ventricle or initiation on the atrium. Optical mapping showed that the block affects action potentials and not just calcium or contraction. Increased resting intracellular calcium was observed after a 30-s exposure to the inhibition laser, which likely resulted in reduced mechanical function. Further optimization of the laser illumination should reduce potential damage. Stopping cardiac contractions by disrupting electrical activity with infrared inhibition has the potential to be a powerful tool for studying the developing heart.

  7. Phosphanilic Acid Inhibits Dihydropteroate Synthase

    DTIC Science & Technology

    1989-11-01

    dihydropteroate synthases of P. aeruginosa and E . coli were about equally susceptible to inhibition by PA. These results suggest that cells of P. aeruginosa...are more permeable to PA than cells of E . coli . Although a weak inhibitor, PA acted on dihydropteroate synthase in the same manner as the sulfonamides...with which PA is structurally related. Inhibition of E . coli by PA in a basal salts-glucose medium was prevented by p-aminobenzoic acid (pABA). However

  8. Inhibition of MMPs by alcohols

    PubMed Central

    Tezvergil-Mutluay, Arzu; Agee, Kelli A.; Hoshika, Tomohiro; Uchiyama, Toshikazu; Tjäderhane, Leo; Breschi, Lorenzo; Mazzoni, Annalisa; Thompson, Jeremy M.; McCracken, Courtney E.; Looney, Stephen W.; Tay, Franklin R.; Pashley, David H.

    2011-01-01

    Objectives While screening the activity of potential inhibitors of matrix metalloproteinases (MMPs), due to the limited water solubility of some of the compounds, they had to be solubilized in ethanol. When ethanol solvent controls were run, they were found to partially inhibit MMPs. Thus, the purpose of this study was to compare the MMP-inhibitory activity of a series of alcohols. Methods The possible inhibitory activity of a series of alcohols was measured against soluble rhMMP-9 and insoluble matrix-bound endogenous MMPs of dentin in completely demineralized dentin. Increasing concentrations (0.17, 0.86, 1.71 and 4.28 moles/L) of a homologous series of alcohols (i.e. methanol, ethanol, propanols, butanols, pentanols, hexanols, the ethanol ester of methacrylic acid, heptanols and octanol) were compared to ethanediol, and propanediol by regression analysis to calculate the molar concentration required to inhibit MMPs by 50% (i.e. the IC50). Results Using two different MMP models, alcohols were shown to inhibit rhMMP-9 and the endogenous proteases of dentin matrix in a dose-dependent manner. The degree of MMP inhibition by alcohols increased with chain length up to 4 methylene groups. Based on the molar concentration required to inhibit rhMMP-9 fifty percent, 2-hydroxyethylmethacrylate (HEMA), 3-hexanol, 3-heptanol and 1-octanol gave the strongest inhibition. Significance The results indicate that alcohols with 4 methylene groups inhibit MMPs more effectively than methanol or ethanol. MMP inhibition was inversely related to the Hoy's solubility parameter for hydrogen bonding forces of the alcohols (i.e. to their hydrophilicity). PMID:21676453

  9. Inhibition of Hageman factor activation

    PubMed Central

    Nossel, H. L.; Rubin, H.; Drillings, M.; Hsieh, R.

    1968-01-01

    A method for studying inhibitors of the contact stages of blood coagulation is described. A number of positively charged substances were shown to inhibit the contact stages. The inhibitory substances include spermine, cytochrome c, ribonuclease, and lysozyme. The inhibitory effect of these substances was neutralized by the addition of an activated plasma thromboplastin antecedent, factor XI, (PTA) fraction. Other positively charged substances including protamine, hexadimethrine, polylysine, polyornithine, methylene blue, and ortho-toluidine blue also inhibited the contact stages of coagulation, but the inhibitory effect on coagulation was not neutralized by the activated PTA fraction. Negatively charged substances such as heparin and insulin did not inhibit the contact stages of coagulation. Cytochrome c inhibited Celite adsorption of a partially purified Hageman factor fraction, and cytochrome, ribonuclease, spermine, and lysozome inhibited the adsorption of Hageman factor from PTA-deficient plasma. Very much smaller quantities of Celite completely adsorbed Hageman factor from the fraction rather than from whole plasma, which suggested the possibility that plasma contains an inhibitor or inhibitors of Hageman factor adsorption. Furthermore cytochrome c, spermine, ribonuclease, and lysozyme inhibited the coagulant activity of the following activators of the Hageman and PTA factors: Celite, kaolin, sodium stearate, ellagic acid, and skin. It is suggested that negatively charged sites on these activators are critical for adsorption and activation and that inhibition results from neutralization of the negatively charged sites by the adsorbed inhibtor. Tests with polylysine polymers indicate that inhibitory activity is directly related to molecular size over the molecular weight range of 4000 to 100,000. PMID:5645860

  10. Lateral Inhibition during Nociceptive Processing.

    PubMed

    Quevedo, Alexandre S; Mørch, Carsten Dahl; Andersen, Ole K; Coghill, Robert C

    2017-02-11

    Spatial summation of pain is the increase of perceived intensity that occurs as the stimulated area increases. Spatial summation of pain is sub-additive in that increasing the stimulus area produces a disproportionately small increase in the perceived intensity of pain. A possible explanation for sub-additive summation may be that convergent excitatory information is modulated by lateral inhibition. To test the hypothesis that lateral inhibition may limit spatial summation of pain, we delivered different patterns of noxious thermal stimuli to the abdomens of 15 subjects using a computer-controlled CO2-laser. Lines (5mm wide) of variable lengths (4cm, 8cm) were compared to two-point stimuli delivered at the same position/separation as the length of lines. When compared to one-point control stimuli, two-point stimulus patterns produced statistically significant spatial summation of pain, while no such summation was detected during line stimulus patterns. Direct comparison of pain intensity evoked by two-point pattern stimuli with line pattern stimuli revealed that two-point patterns were perceived as significantly more painful, despite the fact that the two-point pattern stimulated far smaller areas of skin. Thus, the stimulation of the skin region between the endpoints of the lines appears to produce inhibition. These findings indicate that lateral inhibition limits spatial summation of pain and is an intrinsic component of nociceptive information processing. Disruption of such lateral inhibition may contribute substantially to the radiation of some types of chronic pain.

  11. CD66-mediated phagocytosis of Opa52 Neisseria gonorrhoeae requires a Src-like tyrosine kinase- and Rac1-dependent signalling pathway.

    PubMed

    Hauck, C R; Meyer, T F; Lang, F; Gulbins, E

    1998-01-15

    The interaction of Neisseria gonorrhoeae with human phagocytes is a hallmark of gonococcal infections. Recently, CD66 molecules have been characterized as receptors for Opa52-expressing gonococci on human neutrophils. Here we show that Opa52-expressing gonococci or Escherichia coli or F(ab) fragments directed against CD66, respectively, activate a signalling cascade from CD66 via Src-like protein tyrosine kinases, Rac1 and PAK to Jun-N-terminal kinase. The induced signal is distinct from Fcgamma-receptor-mediated signalling and is specific for Opa52, since piliated Opa- gonococci, commensal Neisseria cinerea or E.coli do not stimulate this signalling pathway. Inhibition of Src-like kinases or Rac1 prevents the uptake of Opa52 bacteria, demonstrating the crucial role of this signalling cascade for the opsonin-independent, Opa52/CD66-mediated phagocytosis of pathogenic Neisseria.

  12. Remote inhibition of polymer degradation.

    SciTech Connect

    Clough, Roger Lee; Celina, Mathias Christopher

    2005-08-01

    Polymer degradation has been explored on the basis of synergistic infectious and inhibitive interaction between separate materials. A dual stage chemiluminescence detection system with individually controlled hot stages was applied to probe for interaction effects during polymer degradation in an oxidizing environment. Experimental confirmation was obtained that volatile antioxidants can be transferred over a relatively large distance. The thermal degradation of a polypropylene (PP) sample receiving traces of inhibitive antioxidants from a remote source is delayed. Similarly, volatiles from two stabilized elastomers were also capable of retarding a degradation process remotely. This observation demonstrates inhibitive cross-talk as a novel interactive phenomenon between different polymers and is consequential for understanding general polymer interactions, fundamental degradation processes and long-term aging effects of multiple materials in a single environment.

  13. Strigolactone inhibition of shoot branching.

    PubMed

    Gomez-Roldan, Victoria; Fermas, Soraya; Brewer, Philip B; Puech-Pagès, Virginie; Dun, Elizabeth A; Pillot, Jean-Paul; Letisse, Fabien; Matusova, Radoslava; Danoun, Saida; Portais, Jean-Charles; Bouwmeester, Harro; Bécard, Guillaume; Beveridge, Christine A; Rameau, Catherine; Rochange, Soizic F

    2008-09-11

    A carotenoid-derived hormonal signal that inhibits shoot branching in plants has long escaped identification. Strigolactones are compounds thought to be derived from carotenoids and are known to trigger the germination of parasitic plant seeds and stimulate symbiotic fungi. Here we present evidence that carotenoid cleavage dioxygenase 8 shoot branching mutants of pea are strigolactone deficient and that strigolactone application restores the wild-type branching phenotype to ccd8 mutants. Moreover, we show that other branching mutants previously characterized as lacking a response to the branching inhibition signal also lack strigolactone response, and are not deficient in strigolactones. These responses are conserved in Arabidopsis. In agreement with the expected properties of the hormonal signal, exogenous strigolactone can be transported in shoots and act at low concentrations. We suggest that endogenous strigolactones or related compounds inhibit shoot branching in plants. Furthermore, ccd8 mutants demonstrate the diverse effects of strigolactones in shoot branching, mycorrhizal symbiosis and parasitic weed interaction.

  14. Substrate inhibition competes with halide inhibition in polyphenol oxidase.

    PubMed

    Lim, Giselle Grace Fernando; Imura, Yuki; Yoshimura, Etsuro

    2012-10-01

    Polyphenol oxidase (PPO) is a ubiquitous enzyme important in the food industry. Although PPO activity followed Michaelis-Menten kinetics at catechol concentrations of up to 1 mM, it slowly decreased at catechol concentrations above 2 mM. This result indicated that in addition to the active site (site A), the enzyme possesses a second catechol-binding site (site B) that exerts an inhibitory effect on PPO activity. Halides inhibit PPO activity in such a way that substrate inhibition is lessened when halide concentration is increased. Furthermore, elevated concentrations of catechol diminished the degree of inhibition by halides. These findings suggest that halides also bind to site B to inhibit PPO activity. A steady-state kinetic analysis demonstrated that the dissociation constant between catechol and PPO depended on the binding of halides to site B. The dissociation constants were greatest when chloride bound to the site. Bromide and iodide yielded lower dissociation constants, in that order. These data indicate that the binding of halide to site B modulated the structure of site A, thereby exerting an inhibitory effect.

  15. Post-Stop-Signal Adjustments: Inhibition Improves Subsequent Inhibition

    ERIC Educational Resources Information Center

    Bissett, Patrick G.; Logan, Gordon D.

    2012-01-01

    Performance in the stop-signal paradigm involves a balance between going and stopping, and one way that this balance is struck is through shifting priority away from the go task, slowing responses after a stop signal, and improving the probability of inhibition. In 6 experiments, the authors tested whether there is a corresponding shift in…

  16. Action spectra for photosynthetic inhibition

    NASA Technical Reports Server (NTRS)

    Caldwell, M. M.; Flint, S.; Camp, L. B.

    1981-01-01

    The ultraviolet action spectrum for photosynthesis inhibition was determined to fall between that of the general DNA action spectrum and the generalized plant action spectrum. The characteristics of this action spectrum suggest that a combination of pronounced increase in effectiveness with decreasing wavelength, substantial specificity for the UV-B waveband, and very diminished response in the UV-A waveband result in large radiation amplification factors when the action spectra are used as weighting functions. Attempted determination of dose/response relationships for leaf disc inhibition provided inconclusive data from which to deconvolute an action spectrum.

  17. Homo economicus belief inhibits trust.

    PubMed

    Xin, Ziqiang; Liu, Guofang

    2013-01-01

    As a foundational concept in economics, the homo economicus assumption regards humans as rational and self-interested actors. In contrast, trust requires individuals to believe partners' benevolence and unselfishness. Thus, the homo economicus belief may inhibit trust. The present three experiments demonstrated that the direct exposure to homo economicus belief can weaken trust. And economic situations like profit calculation can also activate individuals' homo economicus belief and inhibit their trust. It seems that people's increasing homo economicus belief may serve as one cause of the worldwide decline of trust.

  18. Acute ethanol administration inhibits Toll-like receptor 4 signaling pathway in rat intestinal epithelia.

    PubMed

    Zhou, Chao; Zhao, Ji; Li, Jing; Wang, Haiying; Tang, Chengwei

    2013-05-01

    Excess alcohol intake, as in binge drinking, increases susceptibility to microbial pathogens. Alcohol impairs macrophage function by suppression of the Toll-like receptor 4 (TLR4) pathway. This study investigated the effects of acute ethanol intake on the TLR4 pathway in rat intestinal epithelia, which usually encounters luminal antigens at first and participates in the development of intestinal immunity. Twenty Wistar rats were randomly assigned to an ethanol group given ethanol as a 25% (v/v) solution in water at 7.5 g/kg, or a control group given saline, by oral gavage daily for 3 days. The epithelial histology and ultrastructure, the intestinal microflora, peripheral and portal venous plasma lipopolysaccharide (LPS) levels, and somatostatin (SST) levels in the peripheral plasma and small intestine were evaluated. Somatostatin receptor 2 (SSTR2), TLR4, TANK binding kinase-1 (TBK1), activated nuclear factor-κB (NF-κB), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) in the intestinal mucosa were assayed. LPS responsiveness with or without SST pretreatment was assayed in vitro by quantification of TLR4, TBK1, activated NF-κB, IFN-γ and TNF-α in isolated intestinal epithelia. Mucosal damage was observed in the ethanol group by light and electron microscopy. Escherichia coli cultures were unchanged in rat intestine of the ethanol group compared with controls, but lactobacilli cultures were reduced (p < 0.05). LPS levels increased in peripheral and portal venous plasma (p < 0.05), but mucosal TLR4, TBK1, nuclear NF-κB, IFN-γ and TNF-α were unchanged in the ethanol group. LPS treatment in vitro up-regulated the level of TLR4, TBK1 and nuclear NF-κB as well as the production of IFN-γ and TNF-α in isolated intestinal epithelia in the control (p < 0.05), but not the ethanol group. The stimulatory effects of LPS on intestinal epithelia isolated from the control group were significantly inhibited by SST pretreatment (p < 0.05). The

  19. Prostacyclin analogs inhibit fibroblast migration.

    PubMed

    Kohyama, Tadashi; Liu, Xiangde; Kim, Hui Jung; Kobayashi, Tetsu; Ertl, Ronald F; Wen, Fu-Qiang; Takizawa, Hajime; Rennard, Stephen I

    2002-08-01

    The controlled accumulation of fibroblasts to sites of inflammation is crucial to effective tissue repair after injury. Either inadequate or excessive accumulation of fibroblasts could result in abnormal tissue function. Prostacyclin (PGI(2)) is a potent mediator in the coagulation and inflammatory processes. The aim of this study was to investigate the effect of PGI(2) on chemotaxis of human fetal lung fibroblasts (HFL-1). Using the blind well chamber technique, we found that the PGI(2) analog carbaprostacyclin (10(-6) M) inhibited HFL-1 chemotaxis to human plasma fibronectin (20 microg/ml) 58.0 +/- 13.2% (P < 0.05) and to platelet-derived growth factor (PDGF)-BB (10 ng/ml) 48.7 +/- 4.6% (P < 0.05). Checkerboard analysis demonstrated that carbaprostacyclin inhibits both directed and undirected migration. The inhibitory effect of the carbaprostacyclin was concentration dependent and blocked by the cAMP-dependent protein kinase (PKA) inhibitor KT-5720, suggesting that a cAMP-PKA pathway may be involved in the process. Two other PGI(2) analogs, ciprostene and dehydro-15-cyclohexyl carbaprostacyclin (both 10(-6) M), significantly inhibited fibroblast migration to fibronectin. In summary, PGI(2) appears to inhibit fibroblast chemotaxis to fibronectin and PDGF-BB. Such an effect may contribute to the regulation of fibroblasts in wound healing and could contribute to the pathogenesis of diseases characterized by abnormal tissue repair remodeling.

  20. Neuronal Inhibition under the Spotlight.

    PubMed

    Mortensen, Martin; Smart, Trevor G

    2015-12-02

    In this issue of Neuron,Lin et al. (2015) report an optical method to precisely manipulate the activity of GABAA receptors by designing a mutant receptor that binds photosensitive compounds. This allows for studying GABAA receptors in situ and represents a valuable tool to investigate how inhibition affects brain physiology.

  1. Tagetitoxin inhibits chloroplast RNA synthesis

    SciTech Connect

    Mathews, D.E.; Durbin, R.D.

    1987-04-01

    Tagetitoxin is a non-host specific phytotoxin which inhibits chloroplast development. Chloroplast encoded gene products as well as their transcripts are conspicuously depleted in toxin-treated tissue. Intact chloroplasts from 8-9 day old peas were incubated for 60 min. in the presence of tagetitoxin. This treatment reduced RNA synthesis but did not affect protein synthesis as measured by the incorporation of radiolabeled uridine or methionine, respectively. Tagetitoxin also inhibited chloroplast RNA synthesis in vitro. Total UTP incorporation was reduced 50% by 0.5..mu..M tagetitoxin in transcriptionally active chloroplast extracts containing 5mg/ml protein. In vitro transcription with purified E. coli RNA polymerase was also inhibited by tagetitoxin, yet wheat germ RNA polymerase II and several bacteriophage RNA polymerase enzymes were unaffected. Recent evidence suggests that RNA polymerase from chloroplasts and prokaryotes may share extensive homology. In light of this evidence and the authors own data, they propose that tagetitoxin directly inhibits chloroplast RNA polymerase.

  2. Inhibition in Prolonged Work Tasks.

    ERIC Educational Resources Information Center

    van der Ven, A. H. G. S.; And Others

    1989-01-01

    A new model is presented that explains reaction time fluctuations in prolonged work tasks. The model extends the so-called Poisson-Erlang model and accounts for long-term trend effects in the reaction time curve. The model is consistent with Spearman's hypothesis that inhibition increases during work and decreases during rest. (TJH)

  3. Inhibition of carcinogenesis by tea.

    PubMed

    Yang, Chung S; Maliakal, Pius; Meng, Xiaofeng

    2002-01-01

    Tea has received a great deal of attention because tea polyphenols are strong antioxidants, and tea preparations have inhibitory activity against tumorigenesis. The bioavailability and biotransformation of tea polyphenols, however, are key factors limiting these activities in vivo. The inhibition of tumorigenesis by green or black tea preparations has been demonstrated in animal models on different organ sites such as skin, lung, oral cavity, esophagus, forestomach, stomach, small intestine, colon, pancreas, and mammary gland. Epidemiological studies, however, have not yielded clear conclusions concerning the protective effects of tea consumption against cancer formation in humans. The discrepancy between the results from humans and animal models could be due to 1) the much higher doses of tea used in animals in comparison to human consumption, 2) the differences in causative factors between the cancers in humans and animals, and 3) confounding factors limiting the power of epidemiological studies to detect an effect. It is possible that tea may be only effective against specific types of cancer caused by certain etiological factors. Many mechanisms have been proposed for the inhibition of carcinogenesis by tea, including the modulation of signal transduction pathways that leads to the inhibition of cell proliferation and transformation, induction of apoptosis of preneoplastic and neoplastic cells, as well as inhibition of tumor invasion and angiogenesis. These mechanisms need to be evaluated and verified in animal models or humans in order to gain more understanding on the effect of tea consumption on human cancer.

  4. Azide inhibition of urate oxidase.

    PubMed

    Gabison, Laure; Colloc'h, Nathalie; Prangé, Thierry

    2014-07-01

    The inhibition of urate oxidase (UOX) by azide was investigated by X-ray diffraction techniques and compared with cyanide inhibition. Two well characterized sites for reagents are present in the enzyme: the dioxygen site and the substrate-binding site. To examine the selectivity of these sites towards azide inhibition, several crystallization conditions were developed. UOX was co-crystallized with azide (N3) in the presence or absence of either uric acid (UA, the natural substrate) or 8-azaxanthine (8AZA, a competitive inhibitor). In a second set of experiments, previously grown orthorhombic crystals of the UOX-UA or UOX-8AZA complexes were soaked in sodium azide solutions. In a third set of experiments, orthorhombic crystals of UOX with the exchangeable ligand 8-nitroxanthine (8NXN) were soaked in a solution containing uric acid and azide simultaneously (competitive soaking). In all assays, the soaking periods were either short (a few hours) or long (one or two months). These different experimental conditions showed that one or other of the sites, or the two sites together, could be inhibited. This also demonstrated that azide not only competes with dioxygen as cyanide does but also competes with the substrate for its enzymatic site. A model in agreement with experimental data would be an azide in equilibrium between two sites, kinetically in favour of the dioxygen site and thermodynamically in favour of the substrate-binding site.

  5. Behavioral Inhibition: Type or Continuum?

    ERIC Educational Resources Information Center

    Scholmerich, Axel; And Others

    This study investigated whether behavioral inhibition is best conceptualized as a continuous variable or as a distinct typology with two or more subcategories. The following data were gathered on 58 infants at 5, 7, 10, and 13 months of age; physiological functioning (cardiovascular activity and salivary cortisol); emotional expressivity in…

  6. Azide inhibition of urate oxidase

    PubMed Central

    Gabison, Laure; Colloc’h, Nathalie; Prangé, Thierry

    2014-01-01

    The inhibition of urate oxidase (UOX) by azide was investigated by X-ray diffraction techniques and compared with cyanide inhibition. Two well characterized sites for reagents are present in the enzyme: the dioxygen site and the substrate-binding site. To examine the selectivity of these sites towards azide inhibition, several crystallization conditions were developed. UOX was co-crystallized with azide (N3) in the presence or absence of either uric acid (UA, the natural substrate) or 8-azaxanthine (8AZA, a competitive inhibitor). In a second set of experiments, previously grown orthorhombic crystals of the UOX–UA or UOX–8AZA complexes were soaked in sodium azide solutions. In a third set of experiments, orthorhombic crystals of UOX with the exchangeable ligand 8-nitroxanthine (8NXN) were soaked in a solution containing uric acid and azide simultaneously (competitive soaking). In all assays, the soaking periods were either short (a few hours) or long (one or two months). These different experimental conditions showed that one or other of the sites, or the two sites together, could be inhibited. This also demonstrated that azide not only competes with dioxygen as cyanide does but also competes with the substrate for its enzymatic site. A model in agreement with experimental data would be an azide in equilibrium between two sites, kinetically in favour of the dioxygen site and thermodynamically in favour of the substrate-binding site. PMID:25005084

  7. Infant Predictors of Behavioural Inhibition

    ERIC Educational Resources Information Center

    Moehler, Eva; Kagan, Jerome; Oelkers-Ax, Rieke; Brunner, Romuald; Poustka, Luise; Haffner, Johann; Resch, Franz

    2008-01-01

    Behavioural inhibition in the second year of life is a hypothesized predictor for shyness, social anxiety and depression in later childhood, adolescence and even adulthood. To search for the earliest indicators of this fundamental temperamental trait, this study examined whether behavioural characteristics in early infancy can predict behavioural…

  8. Inhibition of Retinoblastoma Protein Inactivation

    DTIC Science & Technology

    2015-09-01

    intracellular growth signals to the cell cycle machinery that drives cell division . Inactivation of Rb pathway function is found in most human cancers...Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The objective of this project is to discover and characterize molecules that inhibit breast cancer cell ...proliferation by maintaining activity of the retinoblastoma protein (Rb). Rb is inactivated to drive proliferation in normal and cancer cells by

  9. Conditioned inhibition and reinforcement rate.

    PubMed

    Harris, Justin A; Kwok, Dorothy W S; Andrew, Benjamin J

    2014-07-01

    We investigated conditioned inhibition in a magazine approach paradigm. Rats were trained on a feature negative discrimination between an auditory conditioned stimulus (CS) reinforced at one rate versus a compound of that CS and a visual stimulus (L) reinforced at a lower rate. This training established L as a conditioned inhibitor. We then tested the inhibitory strength of L by presenting it in compound with other auditory CSs. L reduced responding when tested with a CS that had been reinforced at a high rate, but had less or even no inhibitory effect when tested with a CS that had been reinforced at a low rate. The inhibitory strength of L was greater if it signaled a decrease in reinforcement from an already low rate than if it signaled an equivalent decrease in reinforcement from a high rate. We conclude that the strength of inhibition is not a linear function of the change in reinforcement that it signals. We discuss the implications of this finding for models of learning (e.g., Rescorla & Wagner, 1972) that identify inhibition with a difference (subtraction) rule.

  10. Serotonin, Inhibition, and Negative Mood

    PubMed Central

    Dayan, Peter; Huys, Quentin J. M

    2008-01-01

    Pavlovian predictions of future aversive outcomes lead to behavioral inhibition, suppression, and withdrawal. There is considerable evidence for the involvement of serotonin in both the learning of these predictions and the inhibitory consequences that ensue, although less for a causal relationship between the two. In the context of a highly simplified model of chains of affectively charged thoughts, we interpret the combined effects of serotonin in terms of pruning a tree of possible decisions, (i.e., eliminating those choices that have low or negative expected outcomes). We show how a drop in behavioral inhibition, putatively resulting from an experimentally or psychiatrically influenced drop in serotonin, could result in unexpectedly large negative prediction errors and a significant aversive shift in reinforcement statistics. We suggest an interpretation of this finding that helps dissolve the apparent contradiction between the fact that inhibition of serotonin reuptake is the first-line treatment of depression, although serotonin itself is most strongly linked with aversive rather than appetitive outcomes and predictions. PMID:18248087

  11. Complement inhibition in cancer therapy.

    PubMed

    Pio, Ruben; Ajona, Daniel; Lambris, John D

    2013-02-01

    For decades, complement has been recognized as an effector arm of the immune system that contributes to the destruction of tumor cells. In fact, many therapeutic strategies have been proposed that are based on the intensification of complement-mediated responses against tumors. However, recent studies have challenged this paradigm by demonstrating a tumor-promoting role for complement. Cancer cells seem to be able to establish a convenient balance between complement activation and inhibition, taking advantage of complement initiation without suffering its deleterious effects. Complement activation may support chronic inflammation, promote an immunosuppressive microenvironment, induce angiogenesis, and activate cancer-related signaling pathways. In this context, inhibition of complement activation would be a therapeutic option for treating cancer. This concept is relatively new and deserves closer attention. In this article, we summarize the mechanisms of complement activation on cancer cells, the cancer-promoting effect of complement initiation, and the rationale behind the use of complement inhibition as a therapeutic strategy against cancer.

  12. Genetic and biochemical analysis of gonococcal IgA1 protease: cloning in Escherichia coli and construction of mutants of gonococci that fail to produce the activity.

    PubMed Central

    Koomey, J M; Gill, R E; Falkow, S

    1982-01-01

    The biological significance of bacterial extracellular proteases that specifically cleave human IgA1 is unknown. We have prepared a gene bank of gonococcal chromosomal DNA in Escherichia coli K-12 using a cosmid cloning system. Among these clones, we have identified and characterized an E. coli strain that elaborates an extracellular endopeptidase that is indistinguishable from gonococcal IgA1 protease in its substrate specificity and action on human IgA1. Analysis of recombinant plasmids and examination of plasmid-specific peptides in minicells have shown that the IgA1 protease activity in E. coli is associated with expression of a Mr 140,000 peptide. We have isolated IgA1 protease-deficient mutants of Neisseria gonorrhoeae by reintroduction of physically defined deletions of the cloned gene into the gonococcal chromosome by transformation. Images PMID:6818556

  13. Self-regulation, ego depletion, and inhibition.

    PubMed

    Baumeister, Roy F

    2014-12-01

    Inhibition is a major form of self-regulation. As such, it depends on self-awareness and comparing oneself to standards and is also susceptible to fluctuations in willpower resources. Ego depletion is the state of reduced willpower caused by prior exertion of self-control. Ego depletion undermines inhibition both because restraints are weaker and because urges are felt more intensely than usual. Conscious inhibition of desires is a pervasive feature of everyday life and may be a requirement of life in civilized, cultural society, and in that sense it goes to the evolved core of human nature. Intentional inhibition not only restrains antisocial impulses but can also facilitate optimal performance, such as during test taking. Self-regulation and ego depletion- may also affect less intentional forms of inhibition, even chronic tendencies to inhibit. Broadly stated, inhibition is necessary for human social life and nearly all societies encourage and enforce it.

  14. Chrysin Inhibits Lymphangiogenesis in Vitro.

    PubMed

    Prangsaengtong, Orawin; Athikomkulchai, Sirivan; Xu, Jiuxiang; Koizumi, Keiichi; Inujima, Akiko; Shibahara, Naotoshi; Shimada, Yutaka; Tadtong, Sarin; Awale, Suresh

    2016-01-01

    The induction of lymphangiogenesis is an important process to promote cancer growth and cancer metastasis via the lymphatic system. Identifying the compounds that can prevent lymphangiogenesis for cancer therapy is urgently required. Chrysin, 5,7-dihydroxyflavone, a natural flavone extracted from Thai propolis, was used to investigate the effect on the lymphangiogenesis process of TR-LE, rat lymphatic endothelial cells. In this study, maximal nontoxic doses of chrysin on TR-LE cells were selected by performing a proliferation assay. The process of lymphangiogenesis in vitro was determined by cord formation assay, adhesion assay and migration assay. Chrysin at a nontoxic dose (25 μM) significantly inhibited cord formation, cell adhesion and migration of TR-LE cells when compared with the control group. We also found that chrysin significantly induced vascular endothelial growth factor C (VEGF-C) mRNA expression and nitric oxide (NO) production in TR-LE cells which was involved in decreasing the cord formation of TR-LE cells. In conclusion, we report for the first time that chrysin inhibited the process of lymphangiogenesis in an in vitro model. This finding may prove to be a natural compound for anti-lymphangiogenesis that could be developed for use in cancer therapy.

  15. Graphene: corrosion-inhibiting coating.

    PubMed

    Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

    2012-02-28

    We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating.

  16. Pharmacological inhibition of poly(ADP-ribose) polymerase inhibits angiogenesis

    SciTech Connect

    Rajesh, Mohanraj; Mukhopadhyay, Partha; Batkai, Sandor; Godlewski, Grzegorz; Hasko, Gyoergy; Liaudet, Lucas; Pacher, Pal . E-mail: pacher@mail.nih.gov

    2006-11-17

    Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme which plays an important role in regulating cell death and cellular responses to DNA repair. Pharmacological inhibitors of PARP are being considered as treatment for cancer both in monotherapy as well as in combination with chemotherapeutic agents and radiation, and were also reported to be protective against untoward effects exerted by certain anticancer drugs. Here we show that pharmacological inhibition of PARP with 3-aminobenzamide or PJ-34 dose-dependently reduces VEGF-induced proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro. These results suggest that treatment with PARP inhibitors may exert additional benefits in various cancers and retinopathies by decreasing angiogenesis.

  17. Behavioral Inhibition: Temperament or Prodrome?

    PubMed Central

    Pérez-Edgar, Koraly E.; Guyer, Amanda E.

    2014-01-01

    Individual differences in temperament emerge in the first months of life. Some infants display a heightened sensitivity to novelty and uncertainty in the world around them, leading a subset to fearfully withdraw from the social environment. Extreme forms of this temperament, Behavioral Inhibition (BI), are associated with increased risk for social anxiety disorder. Indeed, the link is so strong that some suggest that BI is not simply a risk factor for anxiety, but rather a milder form of the disorder. The current overview describes the literature linking BI and anxiety, highlighting the unique biobehavioral profiles evident in each construct. It then highlights specific evidence that may help distinguish the form and function of BI and anxiety. Finally, we briefly discuss unresolved issues that may help inform future work aimed at improving our understanding of individual development and shape therapeutic interventions directed at specific mechanisms of disorder. PMID:25101234

  18. Suramin inhibits EV71 infection.

    PubMed

    Wang, Yaxin; Qing, Jie; Sun, Yuna; Rao, Zihe

    2014-03-01

    Enterovirus-71 (EV71) is one of the major causative reagents for hand-foot-and-mouth disease. In particular, EV71 causes severe central nervous system infections and leads to numerous dead cases. Although several inactivated whole-virus vaccines have entered in clinical trials, no antiviral agent has been provided for clinical therapy. In the present work, we screened our compound library and identified that suramin, which has been clinically used to treat variable diseases, could inhibit EV71 proliferation with an IC50 value of 40 μM. We further revealed that suramin could block the attachment of EV71 to host cells to regulate the early stage of EV71 infection, as well as affected other steps of EV71 life cycle. Our results are helpful to understand the mechanism for EV71 life cycle and provide a potential for the usage of an approved drug, suramin, as the antiviral against EV71 infection.

  19. Well having inhibited microbial growth

    DOEpatents

    Lee, Brady D.; Dooley, Kirk J.

    2006-08-15

    The invention includes methods of inhibiting microbial growth in a well. A packing material containing a mixture of a first material and an antimicrobial agent is provided to at least partially fill a well bore. One or more access tubes are provided in an annular space around a casing within the well bore. The access tubes have a first terminal opening located at or above a ground surface and have a length that extends from the first terminal opening at least part of the depth of the well bore. The access tubes have a second terminal opening located within the well bore. An antimicrobial material is supplied into the well bore through the first terminal opening of the access tubes. The invention also includes well constructs.

  20. Regulating anxiety with extrasynaptic inhibition

    PubMed Central

    Botta, Paolo; Demmou, Lynda; Kasugai, Yu; Markovic, Milica; Xu, Chun; Fadok, Jonathan P.; Lu, Tingjia; Poe, Michael M.; Xu, Li; Cook, James M.; Rudolph, Uwe; Sah, Pankaj; Ferraguti, Francesco; Lüthi, Andreas

    2015-01-01

    Aversive experiences can lead to complex behavioral adaptations including increased levels of anxiety and fear generalization. The neuronal mechanisms underlying such maladaptive behavioral changes, however, are poorly understood. Here, using a combination of behavioral, physiological and optogenetic approaches in mouse, we identify a specific subpopulation of central amygdala neurons expressing protein kinase C δ (PKCδ) as key elements of the neuronal circuitry controlling anxiety. Moreover, we show that aversive experiences induce anxiety and fear generalization by regulating the activity of PKCδ+ neurons via extrasynaptic inhibition mediated by α5 subunit-containing GABAA receptors. Our findings reveal that the neuronal circuits that mediate fear and anxiety overlap at the level of defined subpopulations of central amygdala neurons and demonstrate that persistent changes in the excitability of a single cell type can orchestrate complex behavioral changes. PMID:26322928

  1. Notch Signaling Inhibits Axon Regeneration

    PubMed Central

    Bejjani, Rachid El; Hammarlund, Marc

    2013-01-01

    Summary Many neurons have limited capacity to regenerate their axons after injury. Neurons in the mammalian CNS do not regenerate, and even neurons in the PNS often fail to regenerate to their former targets. This failure is likely due in part to pathways that actively restrict regeneration; however, only a few factors that limit regeneration are known. Here, using single-neuron analysis of regeneration in vivo, we show that Notch/lin-12 signaling inhibits the regeneration of mature C. elegans neurons. Notch signaling suppresses regeneration by acting autonomously in the injured cell to prevent growth cone formation. The metalloprotease and gamma-secretase cleavage events that lead to Notch activation during development are also required for its activity in regeneration. Furthermore, blocking Notch activation immediately after injury improves regeneration. Our results define a novel, post-developmental role for the Notch pathway as a repressor of axon regeneration in vivo. PMID:22284182

  2. Latent inhibition in human adults without masking.

    PubMed

    Escobar, Martha; Arcediano, Francisco; Miller, Ralph R

    2003-09-01

    Latent inhibition refers to attenuated responding to Cue X observed when the X-outcome pairings are preceded by X-alone presentations. It has proven difficult to obtain in human adults unless the preexposure (X-alone) presentations are embedded within a masking (i.e., distracting) task. The authors hypothesized that the difficulty in obtaining latent inhibition with unmasked tasks is related to the usual training procedures, in which the preexposure and conditioning experiences are separated by a set of instructions. Experiment 1 reports latent inhibition without masking in a task in which preexposure and conditioning occur without interruption. Experiments 2 and 3 demonstrate that this attenuation in responding to target Cue X does not pass a summation test for conditioned inhibition and is context specific, thereby confirming that it is latent inhibition. Experiments 3 and 4 confirm that introducing instructions between preexposure and conditioning disrupts latent inhibition.

  3. Inhibition of the dorsal premotor cortex does not repair surround inhibition in writer's cramp patients.

    PubMed

    Veugen, Lidwien C; Hoffland, Britt S; Stegeman, Dick F; van de Warrenburg, Bart P

    2013-03-01

    Writer's cramp is a task-specific form of focal dystonia, characterized by abnormal movements and postures of the hand and arm during writing. Two consistent abnormalities in its pathophysiology are a loss of surround inhibition and overactivity of the dorsal premotor cortex (PMd). This study aimed to assess a possible link between these two phenomena by investigating whether PMd inhibition leads to an improvement of surround inhibition, in parallel with previously demonstrated writing improvement. Fifteen writer's cramp patients and ten controls performed a simple motor hand task during which surround inhibition was measured using transcranial magnetic stimulation. Motor cortical excitability was measured of the active and surround muscles at three phases of the task. Surround inhibition and writing performance were assessed before and after PMd inhibitory continuous theta burst stimulation. In contrast to healthy controls, patients did not show inhibition of the abductor digiti minimi muscle during movement initiation of the first dorsal interosseus muscle, confirming the loss of surround inhibition. PMd inhibition led to an improvement of writing speed in writer's cramp patients. However, in both groups, no changes in surround inhibition were observed. The results confirm a role for the PMd in the pathophysiology of writer's cramp. We show that PMd inhibition does not lead to restoration of the surround inhibition defect in writer's cramp, despite the improvement in writing. This questions the involvement of the PMd in the loss of surround inhibition, and perhaps also the direct link between surround inhibition and dystonia.

  4. The inhibition of acquired fear.

    PubMed

    Izquierdo, Iván; Cammarota, Martín; Vianna, Mónica M R; Bevilaqua, Lía R M

    2004-01-01

    A conditioned stimulus (CS) associated with a fearsome unconditioned stimulus (US) generates learned fear. Acquired fear is at the root of a variety of mental disorders, among which phobias, generalized anxiety, the posttraumatic stress disorder (PTSD) and some forms of depression. The simplest way to inhibit learned fear is to extinguish it, which is usually done by repeatedly presenting the CS alone, so that a new association, CS-"no US", will eventually overcome the previously acquired CS-US association. Extinction was first described by Pavlov as a form of "internal inhibition" and was recommended by Freud and Ferenczi in the 1920s (who called it "habituation") as the treatment of choice for phobic disorders. It is used with success till this day, often in association with anxiolytic drugs. Extinction has since then been applied, also successfully and also often in association with anxiolytics, to the treatment of panic, generalized anxiety disorders and, more recently, PTSD. Extinction of learned fear involves gene expression, protein synthesis, N-methyl-D-aspartate (NMDA) receptors and signaling pathways in the hippocampus and the amygdala at the time of the first CS-no US association. It can be enhanced by increasing the exposure to the "no US" component at the time of behavioral testing, to the point of causing the complete uninstallment of the original fear response. Some theorists have recently proposed that reiteration of the CS alone may induce a reconsolidation of the learned behavior instead of its extinction. Reconsolidation would preserve the original memory from the labilization induced by its retrieval. If true, this would of course be disastrous for the psychotherapy of fear-motivated disorders. Here we show that neither the CS nor retrieval cause anything remotely like reconsolidation, but just extinction. In fact, our findings indicate that the reconsolidation hypothesis is essentially incorrect, at least for the form of contextual fear most

  5. Evaluation of antibacterial activity of Calotropis gigentica against Streptococcus mutans and Lactobacillus acidophilus: An in vitro comparative study

    PubMed Central

    Sharma, Meenakshi; Tandon, Sandeep; Aggarwal, Vishal; Bhat, Kishore G; Kappadi, Damodhar; Chandrashekhar, Pavitra; Dorwal, Rakesh

    2015-01-01

    Background: This study was conducted to evaluate in vitro antibacterial potential of ethanolic extract of Calotropis gigentica. Materials and Methods: The inhibitory effect of the ethanolic extract was tested against Streptococcus mutans and Lactobacilli casei by using disc diffusion method. Results: Ethanolic extract of Calotropis gigentica showed 16 mm and 14 mm of minimum inhibition zone at 1.25% concentration for S. mutans and lactobacilli, respectively. Conclusion: Calotropis gigentica was found to effective against S. mutans and lactobacilli. PMID:26752839

  6. Dimethylphosphoryl-inhibited human cholinesterases: inhibition, reactivation, and aging kinetics.

    PubMed

    Worek, F; Diepold, C; Eyer, P

    1999-02-01

    Human poisoning by organophosphates bearing two methoxy groups, e.g. by malathion, paraoxon-methyl, dimethoate and oxydemeton-methyl, is generally considered to be rather resistant to oxime therapy. Since the oxime effectiveness is influenced not only by its reactivating potential but also by inhibition, aging and spontaneous reactivation kinetics, experiments were performed with human acetyl- (AChE) and butyrylcholinesterase (BChE) to determine the respective kinetic constants. The efficacy of obidoxime in reactivating dimethylphosphoryl-AChE was 40, 9 and 3 times higher than of HI 6, pralidoxime and HLö 7, respectively. Aging (t1/2 3.7 h) and spontaneous reactivation (t1/2 0.7 h) occurred concomitantly, with the portion of the aged enzyme being dependent on the presence of excess inhibitor. Calculation of steady-state AChE activity in the presence of inhibitor and oxime revealed that obidoxime was superior to pralidoxime. In addition, organophosphate concentrations up to 10(-6) M (paraoxon-methyl) and 10(-4) M (oxydemeton-methyl) could be counteracted at clinically relevant oxime concentrations (10 microM). These data indicate that oximes may effectively reactivate human dimethylphosphoryl-AChE. Failure of oximes may be attributed to megadose intoxications and to prolonged time intervals between poison uptake and oxime administration. The potency of the oximes to reactivate dimethylphosphoryl-BChE was much lower and the spontaneous reactivation slower (t1/2 9 h), while aging proceeded at a comparable rate. Thus, BChE activity determination for diagnosis and therapeutic monitoring may give no reliable information on AChE status.

  7. Shed syndecan-2 inhibits angiogenesis

    PubMed Central

    De Rossi, Giulia; Evans, Alun R.; Kay, Emma; Woodfin, Abigail; McKay, Tristan R.; Nourshargh, Sussan; Whiteford, James R.

    2014-01-01

    ABSTRACT Angiogenesis is essential for the development of a normal vasculature, tissue repair and reproduction, and also has roles in the progression of diseases such as cancer and rheumatoid arthritis. The heparan sulphate proteoglycan syndecan-2 is expressed on mesenchymal cells in the vasculature and, like the other members of its family, can be shed from the cell surface resulting in the release of its extracellular core protein. The purpose of this study was to establish whether shed syndecan-2 affects angiogenesis. We demonstrate that shed syndecan-2 regulates angiogenesis by inhibiting endothelial cell migration in human and rodent models and, as a result, reduces tumour growth. Furthermore, our findings show that these effects are mediated by the protein tyrosine phosphatase receptor CD148 (also known as PTPRJ) and this interaction corresponds with a decrease in active β1 integrin. Collectively, these data demonstrate an unexplored pathway for the regulation of new blood vessel formation and identify syndecan-2 as a therapeutic target in pathologies characterised by angiogenesis. PMID:25179601

  8. A Generalized Convective Inhibition Energy

    NASA Astrophysics Data System (ADS)

    Tailleux, R.

    2002-12-01

    The common view about preconvecting soundings is that they possess both CAPE (Convective Available Potential Energy) and CINE (Convective INhibition Energy), the latter preventing the former to be spontaneously released. The two concepts of CAPE and CINE are ambiguous, however, because they depend upon the parcel used to compute the work of buoyancy forces, as well as upon the thermodynamic transformation (adiabatic, pseudo-adiabatic) assumed in lifting the parcel. To remove the ambiguity intrinsically associated with CAPE, Randall and Wang (1992) introduced the concept of GCAPE (Generalized CAPE), defined as the minimum achievable energy difference between the total nonkinetic energy (NKE) of the column of air considered minus the total NKE of a reference soundings obtained by reorganizing the parcels along the vertical by conserving mass. Because the method focuses on how to achieve a global energy minimum without addressing the issue of whether it is achievable or how to achieve it, the concept of CINE is lost. The present work shows how to remedy to this problem, and how to define a Generalized CINE within the same framework serving to define the GCAPE.

  9. Cytokinin inhibition of leaf senescence

    PubMed Central

    Zwack, Paul J.; Rashotte, Aaron M.

    2013-01-01

    The senescence delaying effect of cytokinin is well known, however, the details behind how this process occurs remain unclear. Efforts to improve understanding of this phenomenon have led to the identification in Arabidopsis of specific cytokinin signaling components through which senescence signal responses are regulated. These include the cytokinin receptor (AHK3), the type-B response regulator (ARR2) and the recently identified cytokinin response factor (CRF6). At the mechanistic end of this process, it was found that increased cell-wall invertase activity which occurs in response to cytokinin is both necessary and sufficient for the inhibition of senescence. Yet, a direct link between the signaling and mechanistic steps of a cytokinin regulated senescence process has yet to be demonstrated. This may be in part because the relationship between senescence and primary metabolism implied by the key role of cell-wall invertase is the subject of two apparently opposing bodies of evidence. Here we briefly summarize and propose a model in which cytokinin mediated changes in sink/source relationships leads to delayed senescence which is consistent with existing evidence both for and against sugars as a trigger for developmental senescence. PMID:23656876

  10. [Inhibition of premature uterine contractions].

    PubMed

    Troszyński, M; Leibschang, J; Chazan, B; Adamowicz, R; Brankowska, J

    1979-01-01

    Various drugs used to stop premature uterine contractions are discussed in the paper. Particular attention is paid to beta-mimetic drugs. The results of ming Partusisten, one of beta-mimetic drugs, is presented on the material of 104 patients with threatening immature and premature labour. Partusisten was administered in the form of intravenous drip infusion or tablets. During treatment monitoring of the uterine contractility and of foetal heart rate took place. Inhibition of the uterine contraction activity was successful in 100 per cent of cases. In 60,9 per cent in the group of threatening immature labour and in 38,1 per cent in the group threatening premature labour, the delay of delivery was more then 28 days. The delay of delivery by 48 hours was 87 per cent and 84 per cent in both groups respectively. Tachycardia was one of the first side effects observed in 15,2 per cent of cases. There is also presented an example of pregnancy when delivery was delayed by 21 days in spite of premature outflow of amniotic fluid (at a high rupture of membrane). The authors are of the opinion that Partusisten is very effective and gives little side effects, preventing premature uterine contractions. Dosage should be individualized according to the case and labour advancement, and should be based on topographic evaluation of uterine contraction. Negative influence of the drug on foetuses was not observed.

  11. Allosteric Inhibition Through Core Disruption

    SciTech Connect

    Horn, James R.; Shoichet, Brian K.

    2010-03-05

    Although inhibitors typically bind pre-formed sites on proteins, it is theoretically possible to inhibit by disrupting the folded structure of a protein or, in the limit, to bind preferentially to the unfolded state. Equilibria defining how such molecules act are well understood, but structural models for such binding are unknown. Two novel inhibitors of {beta}-lactamase were found to destabilize the enzyme at high temperatures, but at lower temperatures showed no preference for destabilized mutant enzymes versus stabilized mutants. X-ray crystal structures showed that both inhibitors bound to a cryptic site in {beta}-lactamase, which the inhibitors themselves created by forcing apart helixes 11 and 12. This opened up a portion of the hydrophobic core of the protein, into which these two inhibitors bind. Although this binding site is 16 {angstrom} from the center of the active site, the conformational changes were transmitted through a sequence of linked motions to a key catalytic residue, Arg244, which in the complex adopts conformations very different from those in catalytically competent enzyme conformations. These structures offer a detailed view of what has heretofore been a theoretical construct, and suggest the possibility for further design against this novel site.

  12. Selenium inhibition of chemical carcinogenesis.

    PubMed

    Ip, C

    1985-06-01

    In this article I review the work of our laboratory concerning the relationship between dietary Se intake and susceptibility to mammary carcinogenesis induced by 7,12-dimethylbenz[a]anthracene in female rats. The effect of graded levels of Se in the diet was investigated, ranging from deficiency to excessive supplementation that produced marginal toxicity in the animals. In addition, the interdependence between Se status and fat intake was also explored. Further experiments were aimed at defining the role of Se in the initiation and promotion phases of chemical carcinogenesis. In view of the biochemical function of Se as an antioxidant, the chemopreventive efficacy of Se was compared to that of vitamin E in conjunction with their ability to inhibit lipid peroxidation. Results of this study indicated that the antitumorigenic activity of Se could not be accounted for by suppression of tissue peroxidation, although an environment with a lower oxidant stress might enhance the potency of Se in protecting against cancer. The possible mechanisms of action of Se based on the observations and characteristics of several tumor models are briefly discussed.

  13. Substrate inhibition kinetics of phenol biodegradation

    SciTech Connect

    Goudar, C.T.; Ganji, S.H.; Pujar, B.G.; Strevett, K.A.

    2000-02-01

    Phenol biodegradation was studied in batch experiments using an acclimated inoculum and initial phenol concentrations ranging from 0.1 to 1.3 g/L. Phenol depletion an associated microbial growth were monitored over time to provide information that was used to estimate the kinetics of phenol biodegradation. Phenol inhibited biodegradation at high concentrations, and a generalized substrate inhibition model based on statistical thermodynamics was used to describe the dynamics of microbial growth in phenol. For experimental data obtained in this study, the generalized substrate inhibition model reduced to a form that is analogous to the Andrews equation, and the biokinetic parameters {micro}{sub max}, maximum specific growth; K{sub s}, saturation constant; and K{sub i}, inhibition constant were estimated as 0.251 h{sup {minus}1}, 0.011 g/L, and 0.348 g/L, respectively, using a nonlinear least squares technique. Given the wide variability in substrate inhibition models used to describe phenol biodegradation, an attempt was made to justify selection of particular model based on theoretical considerations. Phenol biodegradation data from nine previously published studies were used in the generalized substrate inhibition model to determine the appropriate form of the substrate inhibition model. In all nine cases, the generalized substrate inhibition model reduced to a form analogous to the Andrews equation suggesting the suitability of the Andrews equation to describe phenol biodegradation data.

  14. A Qualitative Approach to Enzyme Inhibition

    ERIC Educational Resources Information Center

    Waldrop, Grover L.

    2009-01-01

    Most general biochemistry textbooks present enzyme inhibition by showing how the basic Michaelis-Menten parameters K[subscript m] and V[subscript max] are affected mathematically by a particular type of inhibitor. This approach, while mathematically rigorous, does not lend itself to understanding how inhibition patterns are used to determine the…

  15. Quorum sensing inhibition, relevance to periodontics.

    PubMed

    Yada, Sudheer; Kamalesh, B; Sonwane, Siddharth; Guptha, Indra; Swetha, R K

    2015-01-01

    Quorum sensing helps bacteria to communicate with each other and in coordinating their behavior. Many diseases of human beings, plants, and animals are mediated by quorum sensing. Various approaches are being tried to inhibit this communication to control the diseases caused by bacteria. Periodontal pathogens also communicate through quorum sensing and new approaches to treat periodontal disease using quorum sensing inhibition need to explored.

  16. Inhibition: Mental Control Process or Mental Resource?

    ERIC Educational Resources Information Center

    Im-Bolter, Nancie; Johnson, Janice; Ling, Daphne; Pascual-Leone, Juan

    2015-01-01

    The current study tested 2 models of inhibition in 45 children with language impairment and 45 children with normally developing language; children were aged 7 to 12 years. Of interest was whether a model of inhibition as a mental-control process (i.e., executive function) or as a mental resource would more accurately reflect the relations among…

  17. Optimal Decision Making in Neural Inhibition Models

    ERIC Educational Resources Information Center

    van Ravenzwaaij, Don; van der Maas, Han L. J.; Wagenmakers, Eric-Jan

    2012-01-01

    In their influential "Psychological Review" article, Bogacz, Brown, Moehlis, Holmes, and Cohen (2006) discussed optimal decision making as accomplished by the drift diffusion model (DDM). The authors showed that neural inhibition models, such as the leaky competing accumulator model (LCA) and the feedforward inhibition model (FFI), can mimic the…

  18. Hydroxyl radical scavengers inhibit lymphocyte mitogenesis.

    PubMed Central

    Novogrodsky, A; Ravid, A; Rubin, A L; Stenzel, K H

    1982-01-01

    Agents that are known to be scavengers of hydroxyl radicals inhibit lymphocyte mitogenesis induced by phorbol myristate acetate (PMA) to a greater extent than they inhibit mitogenesis induced by concanavalin A or phytohemagglutinin. These agents include dimethyl sulfoxide, benzoate, thiourea, dimethylurea, tetramethylurea, L-tryptophan, mannitol, and several other alcohols. Their inhibitory effect is not associated with cytotoxicity. The hydroxyl radical scavengers do not inhibit PMA-dependent amino acid transport in T cells or PMA-induced superoxide production by monocytes. Thus, they do not inhibit the primary interaction of PMA with responding cells. Treatment of peripheral blood mononuclear cells with PMA increased cellular guanylate cyclase in most experiments, and dimethyl sulfoxide tended to inhibit this increase. In addition to inhibition of PMA-induced mitogenesis, hydroxyl radical scavengers markedly inhibited the activity of lymphocyte activating factor (interleukin 1). The differential inhibition of lymphocyte mitogenesis induced by different mitogens appears to be related to the differential macrophage requirements of the mitogens. The data suggest that hydroxyl radicals may be involved in mediating the triggering signal for lymphocyte activation. Some of the hydroxyl radical scavengers are inducers of cellular differentiation,. nd it is possible that their differentiating activity is related to their ability to scavenge free radicals. PMID:6122209

  19. Amiodarone Inhibits Apamin-Sensitive Potassium Currents

    PubMed Central

    Turker, Isik; Yu, Chih-Chieh; Chang, Po-Cheng; Chen, Zhenhui; Sohma, Yoshiro; Lin, Shien-Fong; Chen, Peng-Sheng; Ai, Tomohiko

    2013-01-01

    Background Apamin sensitive potassium current (IKAS), carried by the type 2 small conductance Ca2+-activated potassium (SK2) channels, plays an important role in post-shock action potential duration (APD) shortening and recurrent spontaneous ventricular fibrillation (VF) in failing ventricles. Objective To test the hypothesis that amiodarone inhibits IKAS in human embryonic kidney 293 (HEK-293) cells. Methods We used the patch-clamp technique to study IKAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration. Results Amiodarone inhibited IKAS in a dose-dependent manner (IC50, 2.67±0.25 µM with 1 µM intrapipette Ca2+). Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6±3.1% of IKAS induced with 1 µM intrapipette Ca2+ (n = 3). IKAS inhibition by amiodarone was not voltage-dependent, but was Ca2+-dependent: 30 µM amiodarone inhibited 81.5±1.9% of IKAS induced with 1 µM Ca2+ (n = 4), and 16.4±4.9% with 250 nM Ca2+ (n = 5). Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca2+ dependent inhibition of IKAS. Conclusion Both amiodarone and desethylamiodarone inhibit IKAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca2+ concentration. SK2 current inhibition may in part underlie amiodarone's effects in preventing electrical storm in failing ventricles. PMID:23922993

  20. Hydrogen Sulfide Inhibits Amyloid Formation

    PubMed Central

    2015-01-01

    Amyloid fibrils are large aggregates of misfolded proteins, which are often associated with various neurodegenerative diseases such as Alzheimer’s, Parkinson’s, Huntington’s, and vascular dementia. The amount of hydrogen sulfide (H2S) is known to be significantly reduced in the brain tissue of people diagnosed with Alzheimer’s disease relative to that of healthy individuals. These findings prompted us to investigate the effects of H2S on the formation of amyloids in vitro using a model fibrillogenic protein hen egg white lysozyme (HEWL). HEWL forms typical β-sheet rich fibrils during the course of 70 min at low pH and high temperatures. The addition of H2S completely inhibits the formation of β-sheet and amyloid fibrils, as revealed by deep UV resonance Raman (DUVRR) spectroscopy and ThT fluorescence. Nonresonance Raman spectroscopy shows that disulfide bonds undergo significant rearrangements in the presence of H2S. Raman bands corresponding to disulfide (RSSR) vibrational modes in the 550–500 cm–1 spectral range decrease in intensity and are accompanied by the appearance of a new 490 cm–1 band assigned to the trisulfide group (RSSSR) based on the comparison with model compounds. The formation of RSSSR was proven further using a reaction with TCEP reduction agent and LC-MS analysis of the products. Intrinsic tryptophan fluorescence study shows a strong denaturation of HEWL containing trisulfide bonds. The presented evidence indicates that H2S causes the formation of trisulfide bridges, which destabilizes HEWL structure, preventing protein fibrillation. As a result, small spherical aggregates of unordered protein form, which exhibit no cytotoxicity by contrast with HEWL fibrils. PMID:25545790

  1. Lysophospholipase inhibition by organophosphorus toxicants.

    PubMed

    Quistad, Gary B; Casida, John E

    2004-05-01

    Lysophospholipases (LysoPLAs) are a large family of enzymes for removing lysophospholipids from cell membranes. Potent inhibitors are needed to define the importance of LysoPLAs as targets for toxicants and potential therapeutics. This study considers organophosphorus (OP) inhibitors with emphasis on mouse brain total LysoPLA activity relative to the mipafox-sensitive neuropathy target esterase (NTE)-LysoPLA recently established as 17% of the total activity and important in the action of OP delayed toxicants. The most potent inhibitors of total LysoPLA in mouse brain are isopropyl dodecylphosphonofluoridate (also for LysoPLA of Vibrio bacteria), ethyl octylphosphonofluoridate (EOPF), and two alkyl-benzodioxaphosphorin 2-oxides (BDPOs)[(S)-octyl and dodecyl] (IC50 2-8 nM). OP inhibitors acting in vitro and in vivo differentiate a more sensitive portion but not a distinct NTE-LysoPLA compared with total LysoPLA activity. For 10 active inhibitors, NTE-LysoPLA is 17-fold more sensitive than total LysoPLA, but structure-activity comparisons give a good correlation (r(2) = 0.94) of IC50 values, suggesting active site structural similarity or identity. In mice 4 h after intraperitoneal treatment with discriminating doses, EOPF, tribufos (a plant defoliant), and dodecanesulfonyl fluoride inhibit 41-57% of the total brain LysoPLA and 85-99% of the NTE-LysoPLA activity. Total LysoPLA as well as NTE-LysoPLA is decreased in activity in Nte(+/-)-haploinsufficient mice compared to their Nte(+/+) littermates. The lysolecithin level of spinal cord but not brain is elevated significantly following EOPF treatment (3 mg/kg), thereby focusing attention on localized rather than general alterations in lysophospholipid metabolism in OP-induced hyperactivity and toxicity.

  2. Cardiac remodelling and RAS inhibition

    PubMed Central

    Ferrario, Carlos M.

    2016-01-01

    Risk factors such as hypertension and diabetes are known to augment the activity and tissue expression of angiotensin II (Ang II), the major effector peptide of the renin–angiotensin system (RAS). Overstimulation of the RAS has been implicated in a chain of events that contribute to the pathogenesis of cardiovascular (CV) disease, including the development of cardiac remodelling. This chain of events has been termed the CV continuum. The concept of CV disease existing as a continuum was first proposed in 1991 and it is believed that intervention at any point within the continuum can modify disease progression. Treatment with antihypertensive agents may result in regression of left ventricular hypertrophy, with different drug classes exhibiting different degrees of efficacy. The greatest decrease in left ventricular mass is observed following treatment with angiotensin converting enzyme inhibitors (ACE-Is), which inhibit Ang II formation. Although ACE-Is and angiotensin receptor blockers (ARBs) provide significant benefits in terms of CV events and stroke, mortality remains high. This is partly due to a failure to completely suppress the RAS, and, as our knowledge has increased, an escape phenomenon has been proposed whereby the human sequence of the 12 amino acid substrate angiotensin-(1-12) is converted to Ang II by the mast cell protease, chymase. Angiotensin-(1-12) is abundant in a wide range of organs and has been shown to increase blood pressure in animal models, an effect abolished by the presence of ACE-Is or ARBs. This review explores the CV continuum, in addition to examining the influence of the RAS. We also consider novel pathways within the RAS and how new therapeutic approaches that target this are required to further reduce Ang II formation, and so provide patients with additional benefits from a more complete blockade of the RAS. PMID:27105891

  3. Habituation, latent inhibition, and extinction.

    PubMed

    Jordan, Wesley P; Todd, Travis P; Bucci, David J; Leaton, Robert N

    2015-06-01

    In two conditioned suppression experiments with a latent inhibition (LI) design, we measured the habituation of rats in preexposure, their LI during conditioning, and then extinction over days. In the first experiment, lick suppression, the preexposed group (PE) showed a significant initial unconditioned response (UR) to the target stimulus and significant long-term habituation (LTH) of that response over days. The significant difference between the PE and nonpreexposed (NPE) groups on the first conditioning trial was due solely to the difference in their URs to the conditioned stimulus (CS)-a habituated response (PE) and an unhabituated response (NPE). In the second experiment, bar-press suppression, little UR to the target stimulus was apparent during preexposure, and no detectable LTH. Thus, there was no difference between the PE and NPE groups on the first conditioning trial. Whether the UR to the CS confounds the interpretation of LI (Exp. 1) or not (Exp. 2) can only be known if the UR is measured. In both experiments, LI was observed in acquisition. Also in both experiments, rats that were preexposed and then conditioned to asymptote were significantly more resistant to extinction than were the rats not preexposed. This result contrasts with the consistently reported finding that preexposure either produces less resistance to extinction or has no effect on extinction. The effect of stimulus preexposure survived conditioning to asymptote and was reflected directly in extinction. These two experiments provide a cautionary procedural note for LI experiments and have shown an unexpected extinction effect that may provide new insights into the interpretation of LI.

  4. Praziquantel inhibits Schistosoma mansoni attachment in vitro.

    PubMed

    da-Silva, S P; Noel, F

    1990-01-01

    Male adult Schistosoma mansoni worms were placed in a glass dish containing Tyrode solution and observed for 15 min after addition of praziquantel (0.01 to 1 microM). Praziquantel promoted a concentration- and time-dependent inhibition of sucker-mediated attachment of the worm. Attachment inhibition was correlated with shortening of the parasite. We propose that the rapid and total inhibition of worm attachment observed in vitro with 1 microM praziquantel indicates that therapeutic concentrations of this drug should promote a rapid hepatic shift, in vivo, which may facilitate host tissue reaction.

  5. Lobelane inhibits methamphetamine-evoked dopamine release via inhibition of the vesicular monoamine transporter-2.

    PubMed

    Nickell, Justin R; Krishnamurthy, Sairam; Norrholm, Seth; Deaciuc, Gabriela; Siripurapu, Kiran B; Zheng, Guangrong; Crooks, Peter A; Dwoskin, Linda P

    2010-02-01

    Lobeline is currently being evaluated in clinical trials as a methamphetamine abuse treatment. Lobeline interacts with nicotinic receptor subtypes, dopamine transporters (DATs), and vesicular monoamine transporters (VMAT2s). Methamphetamine inhibits VMAT2 and promotes dopamine (DA) release from synaptic vesicles, resulting ultimately in increased extracellular DA. The present study generated structure-activity relationships by defunctionalizing the lobeline molecule and determining effects on [(3)H]dihydrotetrabenazine binding, inhibition of [(3)H]DA uptake into striatal synaptic vesicles and synaptosomes, the mechanism of VMAT2 inhibition, and inhibition of methamphetamine-evoked DA release. Compared with lobeline, the analogs exhibited greater potency inhibiting DA transporter (DAT) function. Saturated analogs, lobelane and nor-lobelane, exhibited high potency (K(i) = 45 nM) inhibiting vesicular [(3)H]DA uptake, and lobelane competitively inhibited VMAT2 function. Lobeline and lobelane exhibited 67- and 35-fold greater potency, respectively, in inhibiting VMAT2 function compared to DAT function. Lobelane potently decreased (IC(50) = 0.65 microM; I(max) = 73%) methamphetamine-evoked DA overflow, and with a greater maximal effect compared with lobeline (IC(50) = 0.42 microM, I(max) = 56.1%). These results provide support for VMAT2 as a target for inhibition of methamphetamine effects. Both trans-isomers and demethylated analogs of lobelane had reduced or unaltered potency inhibiting VMAT2 function and lower maximal inhibition of methamphetamine-evoked DA release compared with lobelane. Thus, defunctionalization, cis-stereochemistry of the side chains, and presence of the piperidino N-methyl are structural features that afford greatest inhibition of methamphetamine-evoked DA release and enhancement of selectivity for VMAT2. The current results reveal that lobelane, a selective VMAT2 inhibitor, inhibits methamphetamine-evoked DA release and is a promising lead for

  6. Glycerol inhibition of ruminal lipolysis in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of...

  7. TNF inhibition as therapy for rheumatoid arthritis.

    PubMed

    Wollheim, Frank A

    2002-07-01

    The introduction of TNF- alpha -inhibiting biologicals has been a major therapeutic breakthrough in rheumatoid arthritis therapy. Against a background of conventional disease-modifying antirheumatic drug experience, this review focuses on present experiences and possible future developments. TNF inhibition results in profound improvement in the majority of rheumatoid arthritis patients, but non-response and adverse effects need attention. Adalimumab is being filed for approval. Other monoclonal antibodies or receptor constructs are in late development. Small molecule inhibitors of TNF production or signalling are a hot topic. One emerging target is nuclear factor kappa B and selective inhibition has proved effective in animal models of arthritis. Synovial proliferation in rheumatoid arthritis is characterised by diminished apoptosis of fibroblasts, whereas bone marrow precursor cells undergo accelerated apoptosis in active rheumatoid arthritis. Both abnormalities are seemingly ameliorated by TNF inhibition. Anti-apoptotic strategies will soon go into development for control of unresponsive rheumatoid arthritis.

  8. Inhibition of urinary calculi -- a spectroscopic study

    NASA Astrophysics Data System (ADS)

    Manciu, Felicia; Govani, Jayesh; Durrer, William; Reza, Layra; Pinales, Luis

    2008-10-01

    Although a considerable number of investigations have already been undertaken and many causes such as life habits, metabolic disorders, and genetic factors have been noted as sources that accelerate calculi depositions and aggregations, there are still plenty of unanswered questions regarding efficient inhibition and treatment mechanisms. Thus, in an attempt to acquire more insights, we propose here a detailed scientific study of kidney stone formation and growth inhibition based on a traditional medicine approach with Rotula Aquatica Lour (RAL) herbal extracts. A simplified single diffusion gel growth technique was used for synthesizing the samples for the present study. The unexpected Zn presence in the sample with RAL inhibitor, as revealed by XPS measurements, explains the inhibition process and the dramatic reflectance of the incident light observed in the infrared transmission studies. Raman data demonstrate potential binding of the inhibitor with the oxygen of the kidney stone. Photoluminescence results corroborate to provide additional evidence of Zn-related inhibition.

  9. Toxicants inhibiting anaerobic digestion: a review.

    PubMed

    Chen, Jian Lin; Ortiz, Raphael; Steele, Terry W J; Stuckey, David C

    2014-12-01

    Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.

  10. Quorum Sensing Inhibition, Relevance to Periodontics

    PubMed Central

    Yada, Sudheer; Kamalesh, B; Sonwane, Siddharth; Guptha, Indra; Swetha, R K

    2015-01-01

    Quorum sensing helps bacteria to communicate with each other and in coordinating their behavior. Many diseases of human beings, plants, and animals are mediated by quorum sensing. Various approaches are being tried to inhibit this communication to control the diseases caused by bacteria. Periodontal pathogens also communicate through quorum sensing and new approaches to treat periodontal disease using quorum sensing inhibition need to explored. PMID:25709373

  11. Inhibited solid propellant composition containing beryllium hydride

    NASA Technical Reports Server (NTRS)

    Thompson, W. W. (Inventor)

    1978-01-01

    An object of this invention is to provide a composition of beryllium hydride and carboxy-terminated polybutadiene which is stable. Another object of this invention is to provide a method for inhibiting the reactivity of beryllium hydride toward carboxy-terminated polybutadiene. It was found that a small amount of lecithin inhibits the reaction of beryllium hydride with the acid groups in carboxy terminated polybutadiene.

  12. Inhibition of Heme Peroxidases by Melamine

    PubMed Central

    Vanachayangkul, Pattaraporn; Tolleson, William H.

    2012-01-01

    In 2008 melamine-contaminated infant formula and dairy products in China led to over 50,000 hospitalizations of children due to renal injuries. In North America during 2007 and in Asia during 2004, melamine-contaminated pet food products resulted in numerous pet deaths due to renal failure. Animal studies have confirmed the potent renal toxicity of melamine combined with cyanuric acid. We showed previously that the solubility of melamine cyanurate is low at physiologic pH and ionic strength, provoking us to speculate how toxic levels of these compounds could be transported through the circulation without crystallizing until passing into the renal filtrate. We hypothesized that melamine might be sequestered by heme proteins, which could interfere with heme enzyme activity. Four heme peroxidase enzymes were selected for study: horseradish peroxidase (HRP), lactoperoxidase (LPO), and cyclooxygenase-1 and -2 (COX-1 and -2). Melamine exhibited noncompetitive inhibition of HRP (Ki  9.5 ± 0.7 mM), and LPO showed a mixed model of inhibition (Ki  14.5 ± 4.7 mM). The inhibition of HRP and LPO was confirmed using a chemiluminescent peroxidase assay. Melamine also exhibited COX-1 inhibition, but inhibition of COX-2 was not detected. Thus, our results demonstrate that melamine inhibits the activity of three heme peroxidases. PMID:22852071

  13. Inhibition of chymotrypsin by heparin cofactor II.

    PubMed Central

    Church, F C; Noyes, C M; Griffith, M J

    1985-01-01

    Human heparin cofactor II is a plasma protein that is known to inhibit thrombin. The rate of thrombin inhibition by heparin cofactor II is accelerated (greater than or equal to 1000-fold) in the presence of the glycosaminoglycans, heparin and dermatan sulfate. We have found that chymotrypsin A alpha is also inhibited by heparin cofactor II with a second-order rate constant value of 1.8 X 10(6) M-1 X min-1 at pH 8.0 and 25 degrees C. However, there was no measurable effect of heparin or dermatan sulfate on the rate of chymotrypsin inhibition. Arginine-modified heparin cofactor II showed a comparable percentage loss of both antichymotrypsin and antithrombin activities. Heparin cofactor II and chymotrypsin formed a stable complex with a Mr value near 90,000 when analyzed by NaDodSO4/polyacrylamide gel electrophoresis; this suggests a 1:1 reaction stoichiometry. The chymotrypsin cleavage site in heparin cofactor II was the same as that for thrombin, and primary structure analysis of the inhibitor showed a P'1-P'8 sequence of Ser-Thr-Gln-Val-Arg-Phe-Thr-Val ... . The results indicate that, in contrast to alpha 1-antichymotrypsin, which does not inhibit trypsin-like enzymes, including thrombin, heparin cofactor II can effectively inhibit both thrombin and chymotrypsin. PMID:3863104

  14. Piperine, a dietary phytochemical, inhibits angiogenesis

    PubMed Central

    Doucette, Carolyn D.; Hilchie, Ashley L.; Liwski, Robert; Hoskin, David W.

    2012-01-01

    Angiogenesis plays an important role in tumor progression. Piperine, a major alkaloid constituent of black pepper, has diverse physiological actions including killing of cancer cells; however, the effect of piperine on angiogenesis is not known. Here we show that piperine inhibited the proliferation and G1/S transition of human umbilical vein endothelial cells (HUVECs) without causing cell death. Piperine also inhibited HUVEC migration and tubule formation in vitro, as well as collagen-induced angiogenic activity by rat aorta explants and breast cancer cell-induced angiogenesis in chick embryos. Although piperine binds to and activates the cation channel transient receptor potential vanilloid 1 (TRPV1), its effects on endothelial cells did not involve TRPV1 since the antiproliferative effect of piperine was not affected by TRPV1-selective antagonists, nor did HUVECs express detectable TRPV1 mRNA. Importantly, piperine inhibited phosphorylation of Ser 473 and Thr 308 residues of Akt (protein kinase B), which is a key regulator of endothelial cell function and angiogenesis. Consistent with Akt inhibition as the basis of piperine’s action on HUVECs, inhibition of the phosphoinositide-3 kinase/Akt signaling pathway with LY-294002 also inhibited HUVEC proliferation and collagen-induced angiogenesis. Taken together, these data support the further investigation of piperine as an angiogenesis inhibitor for use in cancer treatment. PMID:22902327

  15. Inhibition in the Human Auditory Cortex

    PubMed Central

    Inui, Koji; Nakagawa, Kei; Nishihara, Makoto; Motomura, Eishi; Kakigi, Ryusuke

    2016-01-01

    Despite their indispensable roles in sensory processing, little is known about inhibitory interneurons in humans. Inhibitory postsynaptic potentials cannot be recorded non-invasively, at least in a pure form, in humans. We herein sought to clarify whether prepulse inhibition (PPI) in the auditory cortex reflected inhibition via interneurons using magnetoencephalography. An abrupt increase in sound pressure by 10 dB in a continuous sound was used to evoke the test response, and PPI was observed by inserting a weak (5 dB increase for 1 ms) prepulse. The time course of the inhibition evaluated by prepulses presented at 10–800 ms before the test stimulus showed at least two temporally distinct inhibitions peaking at approximately 20–60 and 600 ms that presumably reflected IPSPs by fast spiking, parvalbumin-positive cells and somatostatin-positive, Martinotti cells, respectively. In another experiment, we confirmed that the degree of the inhibition depended on the strength of the prepulse, but not on the amplitude of the prepulse-evoked cortical response, indicating that the prepulse-evoked excitatory response and prepulse-evoked inhibition reflected activation in two different pathways. Although many diseases such as schizophrenia may involve deficits in the inhibitory system, we do not have appropriate methods to evaluate them; therefore, the easy and non-invasive method described herein may be clinically useful. PMID:27219470

  16. Relationships between inhibition constants, inhibitor concentrations for 50% inhibition and types of inhibition: new ways of analysing data.

    PubMed Central

    Cortés, A; Cascante, M; Cárdenas, M L; Cornish-Bowden, A

    2001-01-01

    The concentration of an inhibitor that decreases the rate of an enzyme-catalysed reaction by 50%, symbolized i(0.5), is often used in pharmacological studies to characterize inhibitors. It can be estimated from the common inhibition plots used in biochemistry by means of the fact that the extrapolated inhibitor concentration at which the rate becomes infinite is equal to -i(0.5). This method is, in principle, more accurate than comparing the rates at various different inhibitor concentrations, and inferring the value of i(0.5) by interpolation. Its reciprocal, 1/i(0.5), is linearly dependent on v(0)/V, the uninhibited rate divided by the limiting rate, and the extrapolated value of v(0)/V at which 1/i(0.5) is zero allows the type of inhibition to be characterized: this value is 1 if the inhibition is strictly competitive; greater than 1 if the inhibition is mixed with a predominantly competitive component; infinite (i.e. 1/i(0.5) does not vary with v(0)/V) if the inhibition is pure non-competitive (i.e. mixed with competitive and uncompetitive components equal); negative if the inhibition is mixed with a predominantly uncompetitive component; and zero if it is strictly uncompetitive. The type of analysis proposed has been tested experimentally by examining inhibition of lactate dehydrogenase by oxalate (an uncompetitive inhibitor with respect to pyruvate) and oxamate (a competitive inhibitor with respect to pyruvate), and of cytosolic malate dehydrogenase by hydroxymalonate (a mixed inhibitor with respect to oxaloacetate). In all cases there is excellent agreement between theory and experiment. PMID:11415458

  17. Iminosugars Inhibit Dengue Virus Production via Inhibition of ER Alpha-Glucosidases—Not Glycolipid Processing Enzymes

    PubMed Central

    Sayce, Andrew C.; Alonzi, Dominic S.; Killingbeck, Sarah S.; Tyrrell, Beatrice E.; Hill, Michelle L.; Caputo, Alessandro T.; Iwaki, Ren; Kinami, Kyoko; Ide, Daisuke; Kiappes, J. L.; Beatty, P. Robert; Kato, Atsushi; Harris, Eva; Dwek, Raymond A.; Miller, Joanna L.; Zitzmann, Nicole

    2016-01-01

    It has long been thought that iminosugar antiviral activity is a function of inhibition of endoplasmic reticulum-resident α-glucosidases, and on this basis, many iminosugars have been investigated as therapeutic agents for treatment of infection by a diverse spectrum of viruses, including dengue virus (DENV). However, iminosugars are glycomimetics possessing a nitrogen atom in place of the endocyclic oxygen atom, and the ubiquity of glycans in host metabolism suggests that multiple pathways can be targeted via iminosugar treatment. Successful treatment of patients with glycolipid processing defects using iminosugars highlights the clinical exploitation of iminosugar inhibition of enzymes other than ER α-glucosidases. Evidence correlating antiviral activity with successful inhibition of ER glucosidases together with the exclusion of alternative mechanisms of action of iminosugars in the context of DENV infection is limited. Celgosivir, a bicyclic iminosugar evaluated in phase Ib clinical trials as a therapeutic for the treatment of DENV infection, was confirmed to be antiviral in a lethal mouse model of antibody-enhanced DENV infection. In this study we provide the first evidence of the antiviral activity of celgosivir in primary human macrophages in vitro, in which it inhibits DENV secretion with an EC50 of 5 μM. We further demonstrate that monocyclic glucose-mimicking iminosugars inhibit isolated glycoprotein and glycolipid processing enzymes and that this inhibition also occurs in primary cells treated with these drugs. By comparison to bicyclic glucose-mimicking iminosugars which inhibit glycoprotein processing but do not inhibit glycolipid processing and galactose-mimicking iminosugars which do not inhibit glycoprotein processing but do inhibit glycolipid processing, we demonstrate that inhibition of endoplasmic reticulum-resident α-glucosidases, not glycolipid processing, is responsible for iminosugar antiviral activity against DENV. Our data suggest that

  18. Chemical inhibition of nitrification in activated sludge.

    PubMed

    Kelly, R T; Henriques, I D S; Love, N G

    2004-03-20

    Conventional aerobic nitrification was adversely affected by single pulse inputs of six different classes of industrially relevant chemical toxins: an electrophilic solvent (1-chloro-2,4-dinitrobenzene, CDNB), a heavy metal (cadmium), a hydrophobic chemical (1-octanol), an uncoupling agent (2,4-dinitrophenol, DNP), alkaline pH, and cyanide in its weak metal complexed form. The concentrations of each chemical source that caused 1 5, 25, and 50% respiratory inhibition of a nitrifying mixed liquor during a short-term assay were used to shock sequencing batch reactors containing nitrifying conventional activated sludge. The reactors were monitored for recovery over a period of 30 days or less. All shock conditions inhibited nitrification, but to different degrees. The nitrate generation rate (NGR) of the shocked reactors recovered overtime to control reactor levels and showed that it was a more sensitive indicator of nitrification inhibition than both initial respirometric tests conducted on unexposed biomass and effluent nitrogen species analyses. CDNB had the most severe impact on nitrification, followed by alkaline pH 11, cadmium, cyanide, octanol, and DNP. Based on effluent data, cadmium and octanol primarily inhibited ammonia-oxidizing bacteria (AOB) while CDNB, pH 11,and cyanide inhibited both AOB and nitrite-oxidizing bacteria (NOB). DNP initially inhibited nitrification but quickly increased the NGR relative to the control and stimulated nitrification after several days in a manner reflective of oxidative uncoupling. The shocked mixed liquor showed trends toward recovery from inhibition for all chemicals tested, but in some cases this reversion was slow. These results contribute to our broader effort to identify relationships between chemical sources and the process effects they induce in activated sludge treatment systems.

  19. [Induction of the NO synthesis in lactobacilli under stress conditions].

    PubMed

    Smolentseva, O A; Iarullina, D R; Il'inskaia, O N

    2012-01-01

    An increase in the nitric oxide (NO) biosynthesis in Lactobacillus plantarum 8P-A3 cells takes place under strong stress influence, which leads to a considerable decrease in the microbial cell viability: heating at 70 degrees C and 80 degrees C, prolonged cultivation, toxic effect of hexylresorcinol. The factors, which do not lead to cell death, such as heating at 60 degrees C, 50 microg/ml homoserine lactone, Bacillus intermedius 7P ribonuclease (binase) in concentrations up to 300 microg/ml, do not induce NO synthesis. The activation of the NO biosynthesis in response to stress treatment evidences to universality of key-mechanisms of stress response in cells differing in the level of their organization as well as to important role of nitric oxide in them.

  20. Characterization and selection of lactobacilli isolated from Spanish fermented sausages.

    PubMed

    Rovira, A; Nieto, J C; Rodríguez, A; Reguera, J I; González, Z

    1997-06-01

    The use of starter cultures to control and run the fermentative process is a usual way of manufacturing sausages in meat industries. The first stage in the starter culture designing process is to characterize the lactic acid bacteria isolated from these meat products, in order to select the best strains. The strains used for this study were isolated from different dry fermented sausages, obtained during the manufacturing process. The main tests used to identify the isolated bacteria were: microscopic-morphologic characteristics, catalase activity, production of gas, growth at 8, 15 and 45 degrees C, fermentation of carbohydrates and production of lactic acid isomers. A total of 194 strains were identified. Lactobacillus sake and Lactobacillus plantarum were the most frequent species. Other microbiological tests were also performed, and three strains of Lactobacillus sake were found which did not produce dextran from sucrose.

  1. Expression and secretion of cholera toxin B subunit in lactobacilli.

    PubMed

    Okuno, Takahiro; Kashige, Nobuhiro; Satho, Tomomitsu; Irie, Keiichi; Hiramatsu, Yukihiro; Sharmin, Tanjina; Fukumitsu, Yuki; Uyeda, Saori; Yamada, Seitaro; Harakuni, Tetsuya; Miyata, Takeshi; Arakawa, Takeshi; Imoto, Masumi; Toda, Akihisa; Nakashima, Yukihiko; Miake, Fumio

    2013-01-01

    Lactic acid bacteria (LAB) are used in various fields, including in food and medical supplies. There has been a great deal of research into vaccine development using LAB as carriers due to their "generally recognized as safe" status. Cholera is an infectious disease that causes diarrhea due to cholera toxin (CT) produced by Vibrio cholerae. The pentameric cholera toxin B (CTB) subunit has no toxicity, and is used as an antigen in cholera vaccines and as a delivery molecule in vaccines to various diseases. In this study, we generated recombinant LAB expressing and secreting CTB. Here, we first report that CTB expressed and secreted from LAB bound to GM1 ganglioside. The secreted CTB was purified, and its immunogenicity was determined by intranasal administration into mice. The results of the present study suggested that it may be useful as the basis of a new oral cholera vaccine combining LAB and CTB.

  2. Impact of Hydroxychloroquine-Loaded Polyurethane Intravaginal Rings on Lactobacilli

    PubMed Central

    Traore, Yannick Leandre; Chen, Yufei; Bernier, Anne-Marie

    2015-01-01

    The use of polymeric devices for controlled sustained delivery of drugs is a promising approach for the prevention of HIV-1 infection. Unfortunately, certain microbicides, when topically applied vaginally, may be cytotoxic to vaginal epithelial cells and the protective microflora present within the female genital tract. In this study, we evaluated the impact of hydroxychloroquine (HCQ)-loaded, reservoir-type, polyurethane intravaginal rings (IVRs) on the growth of Lactobacillus crispatus and Lactobacillus jensenii and on the viability of vaginal and ectocervical epithelial cells. The IVRs were fabricated using hot-melt injection molding and were capable of providing controlled release of HCQ for 24 days, with mean daily release rates of 17.01 ± 3.6 μg/ml in sodium acetate buffer (pH 4) and 29.45 ± 4.84 μg/ml in MRS broth (pH 6.2). Drug-free IVRs and the released HCQ had no significant effects on bacterial growth or the viability of vaginal or ectocervical epithelial cells. Furthermore, there was no significant impact on the integrity of vaginal epithelial cell monolayers, in comparison with controls, as measured by transepithelial electrical resistance. Overall, this is the first study to evaluate the effects of HCQ-loaded IVRs on the growth of vaginal flora and the integrity of vaginal epithelial cell monolayers. PMID:26416871

  3. Inhibition of pear fruit ripening by mannose.

    PubMed

    Watkins, C B; Frenkel, C

    1987-09-01

    Softening of the flesh and the rise in ethylene evolution and respiration associated with ripening in pear (Pyrus communis L.) fruit was delayed when mannose was vacuum infiltrated into intact fruit. The extent of delay could be modified by altering the concentration or the volume of mannose applied to the fruit. Inhibition of ripening was associated with phosphorylation of mannose to mannose 6-phosphate (M6P), and accumulation of M6P was associated with lowered levels of inorganic phosphate (Pi), glucose 6-phosphate (G6P), and ATP in the fruit tissue. Subsequently, however, as the M6P was metabolized, the levels of Pi, G6P, and ATP increased and ripening processes were concomitantly released from inhibition. Hence, the degree of inhibition by mannose or the release from inhibition was related to the level of M6P in the fruit and its rate of metabolism. The data provide correlative evidence to support a view that one inhibitory effect of mannose is depletion of Pi in the cell as a result of phosphorylation of mannose to M6P. Inhibition of ripening by mannose was not alleviated by co-application of glucose as a competitive substrate for the hexokinase(s), or by Pi, presumably the depleted metabolite. Also, incubation of tissue disks with M6P resulted in inhibition of ethylene production and respiration. The structural analogs of mannose, glucosamine, and 2-deoxyglucose, which have been shown to mimic mannose action in several plant tissues, did not cause inhibition of ripening of pear fruit comparable with that associated with mannose. Both analogs stimulated respiration, and glucosamine caused only a small inhibition of softening and ethylene evolution. Another mannose analog, alpha-methylmannoside, did inhibit fruit ripening though to a lesser extent than mannose. Its influence was also associated with accumulation of M6P and a decrease of Pi levels. We conclude that the mannose effect may, in part, be due to M6P toxicity, as well as by depletion of Pi.

  4. Calcium inhibits diacylglycerol uptake by serum albumin.

    PubMed

    Ahyayauch, Hasna; Arana, Gorka; Sot, Jesús; Alonso, Alicia; Goñi, Félix M

    2009-03-01

    Serum albumin is an abundant protein in blood plasma, that is well-known for its ability to transport hydrophobic biomolecules and drugs. Recent hypotheses propose that serum albumin plays a role in the regulation of lipid metabolism in addition to its lipid transport properties. The present work explores the capacity of bovine serum albumin (BSA) to extract diacylglycerols (DAG) from phospholipid bilayers, and the inhibition of such interaction by divalent cations. Quantitative measurements using radioactive DAG and morphological evidence derived from giant unilamellar vesicles examined by confocal microscopy provide concurrent results. BSA extracts DAG from vesicles consisting of phosphatidylinositol/DAG. Long, saturated DAG species are incorporated more readily than the shorter-chain or unsaturated ones. Divalent cations hinder DAG uptake by BSA. For Ca(2+), the concentration causing half-maximal inhibition is approximately 10 muM; 90% inhibition is caused by 100 muM Ca(2+). Sr(2+) requires concentrations one order of magnitude higher, while Mg(2+) has virtually no effect. As an example on how DAG uptake by BSA, and its inhibition by Ca(2+), could play a regulating role in lipid metabolism, a PI-specific phospholipase C has been assayed in the presence of BSA and/or Ca(2+). BSA activates the enzyme by removing the end-product DAG, but the activation is reverted by Ca(2+) that inhibits DAG uptake.

  5. Speech-induced modulation of interhemispheric inhibition.

    PubMed

    Kano, Tadashige; Kobayashi, Masahito; Ohira, Takayuki; Yoshida, Kazunari

    2012-12-07

    This study aimed to determine the effects of speech and mastication on interhemispheric inhibition between the right and left primary motor areas (M1s) by using transcranial magnetic stimulation (TMS). Motor-evoked potentials (MEPs) were recorded from the first dorsal interossei (FDIs) of each hand of 10 healthy right-handed subjects under 3 conditions: at rest (control), during mastication (non-verbal oral movement), and during speech (reading aloud). Test TMS was delivered following conditioning TMS of the contralateral M1 at various interstimulus intervals. Under all conditions, the MEPs in the left FDIs were significantly inhibited after conditioning of the left M1 (i.e. inhibition of the right M1 by TMS of the left hemisphere). In contrast, the left M1 was significantly inhibited by the right hemisphere only during the control and mastication tasks, but not speech task. These results suggest that speech may facilitate the activity of the dominant M1 via functional connectivity between the speech area and the left M1, or may modify the balance of interhemispheric interactions, by suppressing inhibition of the dominant hemisphere by the non-dominant hemisphere. Our findings show a novel aspect of interhemispheric dominance and may improve therapeutic strategies for recovery from stroke.

  6. Response inhibition in motor conversion disorder.

    PubMed

    Voon, Valerie; Ekanayake, Vindhya; Wiggs, Edythe; Kranick, Sarah; Ameli, Rezvan; Harrison, Neil A; Hallett, Mark

    2013-05-01

    Conversion disorders (CDs) are unexplained neurological symptoms presumed to be related to a psychological issue. Studies focusing on conversion paralysis have suggested potential impairments in motor initiation or execution. Here we studied CD patients with aberrant or excessive motor movements and focused on motor response inhibition. We also assessed cognitive measures in multiple domains. We compared 30 CD patients and 30 age-, sex-, and education-matched healthy volunteers on a motor response inhibition task (go/no go), along with verbal motor response inhibition (color-word interference) and measures of attention, sustained attention, processing speed, language, memory, visuospatial processing, and executive function including planning and verbal fluency. CD patients had greater impairments in commission errors on the go/no go task (P < .001) compared with healthy volunteers, which remained significant after Bonferroni correction for multiple comparisons and after controlling for attention, sustained attention, depression, and anxiety. There were no significant differences in other cognitive measures. We highlight a specific deficit in motor response inhibition that may play a role in impaired inhibition of unwanted movement such as the excessive and aberrant movements seen in motor conversion. Patients with nonepileptic seizures, a different form of conversion disorder, are commonly reported to have lower IQ and multiple cognitive deficits. Our results point toward potential differences between conversion disorder subgroups. © 2013 Movement Disorder Society.

  7. Response Inhibition in Motor Conversion Disorder

    PubMed Central

    Voon, Valerie; Ekanayake, Vindhya; Wiggs, Edythe; Kranick, Sarah; Ameli, Rezvan; Harrison, Neil A.; Hallett, Mark

    2014-01-01

    Conversion disorders (CDs) are unexplained neurological symptoms presumed to be related to a psychological issue. Studies focusing on conversion paralysis have suggested potential impairments in motor initiation or execution. Here we studied CD patients with aberrant or excessive motor movements and focused on motor response inhibition. We also assessed cognitive measures in multiple domains. We compared 30 CD patients and 30 age-, sex-, and education-matched healthy volunteers on a motor response inhibition task (go/no go), along with verbal motor response inhibition (color-word interference) and measures of attention, sustained attention, processing speed, language, memory, visuospatial processing, and executive function including planning and verbal fluency. CD patients had greater impairments in commission errors on the go/no go task (P <.001) compared with healthy volunteers, which remained significant after Bonferroni correction for multiple comparisons and after controlling for attention, sustained attention, depression, and anxiety. There were no significant differences in other cognitive measures. We highlight a specific deficit in motor response inhibition that may play a role in impaired inhibition of unwanted movement such as the excessive and aberrant movements seen in motor conversion. Patients with nonepileptic seizures, a different form of conversion disorder, are commonly reported to have lower IQ and multiple cognitive deficits. Our results point toward potential differences between conversion disorder subgroups. PMID:23554084

  8. Magnesium inhibition of calcite dissolution kinetics

    SciTech Connect

    Arvidson, Rolf S.; Collier, Martin; Davis, Kevin J.; Vinson, Michael D.; Amonette, James E.; Luttge, Andreas

    2006-02-01

    We present evidence of inhibition of calcite dissolution by dissolved magnesium through direct observations of the (104) surface using atomic force microscopy (AFM) and vertical scanning interferometry (VSI). Far from equilibrium, the pattern of magnesium inhibition is dependent on solution composition and specific to surface step geometry. In CO2-free solutions (pH 8.8), dissolved magnesium brings about little inhibition even at concentrations of 0.8 x 10-3 molal. At the same pH, magnesium concentrations of less than 0.05 x 10-3 molal in carbonate-buffered solutions generate significant inhibition, although no changes in surface and etch pit morphology are observed. As concentrations exceed magnesite saturation, the dissolution rate shows little additional decrease; however, selective pinning of step edges results in unique etch-pit profiles, seen in both AFM and VSI datasets. Despite the decreases in step velocity, magnesium addition in carbonated solutions also appears to activate the surface by increasing the nucleation rate of new defects. These relationships suggest that the modest depression of the bulk rate measured by VSI reflects a balance between competing reaction mechanisms that simultaneously depress the rate through selective inhibition of step movement, but also enhance reactivity on terraces by lowering the energy barrier to new etch-pit formation.

  9. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants

    PubMed Central

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-01

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity. PMID:26744061

  10. Inhibition of mTOR pathway attenuates migration and invasion of gallbladder cancer via EMT inhibition.

    PubMed

    Zong, Huajie; Yin, Baobing; Zhou, Huading; Cai, Duan; Ma, Baojin; Xiang, Yang

    2014-07-01

    Gallbladder cancer (GBC) is an aggressive disease in which epithelial-mesenchymal transition (EMT) plays a critical role. Whether inhibition of mTOR effects via EMT reversal in GBC remains unclear. Using genetic and pharmacologic inhibitions of mTOR, we investigated the changes of EMT levels in GBC cells. Expressions of EMT related genes were also studied. Migration and invasion assays were carried out and in vivo tumour metastasis mouse models were established. Circulating tumour DNA was quantified. We used EMT index (ratio of Vimentin/Ecadherin expression) to profile EMT levels. We found that inhibition of mTOR using shRNAs and rapamycin inhibited EMT in GBC-SD gallbladder cancer cells. Inhibition of mTOR inhibited EMT in GBC-SD cells in TGF-β-dependent manner, which was contributed majorly by mTORC2 inhibition. Rapamycin decreased invasiveness and migration of GBC-SD cells in vitro and in vivo. We have in the current study shown that rapamycin diminishes the ability of invasion and migration of GBC via inhibition of TGF-β-dependent EMT. Our findings contribute to the understanding of the carcinogenesis of GBC.

  11. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

    PubMed

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-08

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity.

  12. The role of (dis)inhibition in creativity: decreased inhibition improves idea generation.

    PubMed

    Radel, Rémi; Davranche, Karen; Fournier, Marion; Dietrich, Arne

    2015-01-01

    There is now a large body of evidence showing that many different conditions related to impaired fronto-executive functioning are associated with the enhancement of some types of creativity. In this paper, we pursue the possibility that the central mechanism associated with this effect might be a reduced capacity to exert inhibition. We tested this hypothesis by exhausting the inhibition efficiency through prolonged and intensive practice of either the Simon or the Eriksen Flanker task. Performance on another inhibition task indicated that only the cognitive resources for inhibition of participants facing high inhibition demands were impaired. Subsequent creativity tests revealed that exposure to high inhibition demands led to enhanced fluency in a divergent thinking task (Alternate Uses Task), but no such changes occurred in a convergent task (Remote Associate Task; studies 1a and 1b). The same manipulation also led to a hyper-priming effect for weakly related primes in a Lexical Decision Task (Study 2). Together, these findings suggest that inhibition selectively affects some types of creative processes and that, when resources for inhibition are lacking, the frequency and the originality of ideas was facilitated.

  13. Complete corrosion inhibition through graphene defect passivation.

    PubMed

    Hsieh, Ya-Ping; Hofmann, Mario; Chang, Kai-Wen; Jhu, Jian Gang; Li, Yuan-Yao; Chen, Kuang Yao; Yang, Chang Chung; Chang, Wen-Sheng; Chen, Li-Chyong

    2014-01-28

    Graphene is expected to enable superior corrosion protection due to its impermeability and chemical inertness. Previous reports, however, demonstrate limited corrosion inhibition and even corrosion enhancement of graphene on metal surfaces. To enable the reliable and complete passivation, the origin of the low inhibition efficiency of graphene was investigated. Combining electrochemical and morphological characterization techniques, nanometer-sized structural defects in chemical vapor deposition grown graphene were found to be the cause for the limited passivation effect. Extremely fast mass transport on the order of meters per second both across and parallel to graphene layers results in an inhibition efficiency of only ∼50% for Cu covered with up to three graphene layers. Through selective passivation of the defects by atomic layer deposition (ALD) an enhanced corrosion protection of more than 99% was achieved, which compares favorably with commercial corrosion protection methods.

  14. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation.

    PubMed

    Tang, Jun; Lobatto, Mark E; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M; Calcagno, Claudia; Braza, Mounia S; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L; Duivenvoorden, Raphaël; Sager, Hendrik; Astudillo, Yaritzy M; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P; Strijkers, Gustav J; Stroes, Erik S G; Swirski, Filip K; Nahrendorf, Matthias; Fisher, Edward A; Fayad, Zahi A; Mulder, Willem J M

    2015-04-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E deficient mice (Apoe(-/-) ) with advanced atherosclerotic plaques. This resulted in rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an eight-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis.

  15. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation

    PubMed Central

    Tang, Jun; Lobatto, Mark E.; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M.; Calcagno, Claudia; Braza, Mounia S.; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L.; Duivenvoorden, Raphaël; Sager, Hendrik B.; Astudillo, Yaritzy M.; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P.; Strijkers, Gustav J.; Stroes, Erik S. G.; Swirski, Filip K.; Nahrendorf, Matthias; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

    2015-01-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E–deficient mice (Apoe−/−) with advanced atherosclerotic plaques. This resulted in the rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an 8-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis. PMID:26295063

  16. Mesoporous silica nanoparticles inhibit cellular respiration.

    PubMed

    Tao, Zhimin; Morrow, Matthew P; Asefa, Tewodros; Sharma, Krishna K; Duncan, Cole; Anan, Abhishek; Penefsky, Harvey S; Goodisman, Jerry; Souid, Abdul-Kader

    2008-05-01

    We studied the effect of two types of mesoporous silica nanoparticles, MCM-41 and SBA-15, on mitochondrial O 2 consumption (respiration) in HL-60 (myeloid) cells, Jurkat (lymphoid) cells, and isolated mitochondria. SBA-15 inhibited cellular respiration at 25-500 microg/mL; the inhibition was concentration-dependent and time-dependent. The cellular ATP profile paralleled that of respiration. MCM-41 had no noticeable effect on respiration rate. In cells depleted of metabolic fuels, 50 microg/mL SBA-15 delayed the onset of glucose-supported respiration by 12 min and 200 microg/mL SBA-15 by 34 min; MCM-41 also delayed the onset of glucose-supported respiration. Neither SBA-15 nor MCM-41 affected cellular glutathione. Both nanoparticles inhibited respiration of isolated mitochondria and submitochondrial particles.

  17. Zerumbone, Sesquiterpene Photochemical from Ginger, Inhibits Angiogenesis

    PubMed Central

    Park, Ju-Hyung; Park, Geun Mook

    2015-01-01

    Here, we investigated the role of zerumbone, a natural cyclic sesquiterpene of Zingiber zerumbet Smith, on angiogenesis using human umbilical vein endothelial cells (HUVECs). Zerumbone inhibited HUVECs proliferation, migration and tubule formation, as well as angiogenic activity by rat aorta explants. In particular, zerumbone inhibited phosphorylation of vascular endothelial growth factor receptor-2 and fibroblast growth factor receptor-1, which are key regulators of endothelial cell function and angiogenesis. In vivo matrigel plug assay in mice demonstrated significant decrease in vascularization and hemoglobin content in the plugs from zerumbone-treated mice, compared with control mice. Overall, these results suggest that zerumbone inhibits various attributes of angiogenesis, which might contribute to its reported antitumor effects. PMID:26170737

  18. Inhibition of renal alkaline phosphatase by cimetidine.

    PubMed

    Minai-Tehrani, Dariush; Khodai, Somayeh; Aminnaseri, Somayeh; Minoui, Saeed; Sobhani-Damavadifar, Zahra; Alavi, Sana; Osmani, Raheleh; Ahmadi, Shiva

    2011-08-01

    Alkaline phosphatase (ALP) belongs to hydrolase group of enzymes. It is responsible for removing phosphate groups from many types of molecules, including nucleotides and proteins. Cimetidine (trade name Tagamet) is an antagonist of histamine H2-receptor that inhibits the production of gastric acid. Cimetidine is used for the treatment of gastrointestinal diseases. In this study the inhibitory effect of cimetidine on mouse renal ALP activity was investigated. Our results showed that cimetidine can inhibit ALP by uncompetitive inhibition. In the absence of inhibitor the V(max) and K(m) of the enzyme were found to be 13.7 mmol/mg prot.min and 0.25 mM, respectively. Both the Vmax and Km of the enzyme decreased with increasing cimetidine concentrations (0- 1.2 mM). The Ki and IC(50) of cimetidine were determined to be about 0.5 mM and 0.52 mM, respectively.

  19. Terbinafine inhibits gap junctional intercellular communication.

    PubMed

    Lee, Ju Yeun; Yoon, Sei Mee; Choi, Eun Ju; Lee, Jinu

    2016-09-15

    Terbinafine is an antifungal agent that selectively inhibits fungal sterol synthesis by blocking squalene epoxidase. We evaluated the effect of terbinafine on gap junctional intercellular communication (GJIC). Fluorescence recovery after photobleaching (FRAP) and I-YFP GJIC assays revealed that terbinafine inhibits GJIC in a reversible and dose-dependent manner in FRT-Cx43 and LN215 cells. Treatment with terbinafine did not affect Cx43 phosphorylation status or intracellular Ca(2+) concentration, well-known action mechanisms of various GJIC blockers. While a structurally related chemical, naftifine, attenuated GJIC, epigallocatechin gallate, another potent squalene epoxidase inhibitor with a different structure, did not. These results suggest that terbinafine inhibits GJIC with a so far unknown mechanism of action.

  20. Inhibition of Henipavirus infection by RNA interference.

    PubMed

    Mungall, Bruce A; Schopman, Nick C T; Lambeth, Luke S; Doran, Tim J

    2008-12-01

    Nipah virus (NiV) and Hendra virus (HeV) are recently emerged zoonotic paramyxoviruses exclusively grouped within a new genus, Henipavirus. These viruses cause fatal disease in a wide range of species, including humans. Both NiV and HeV have continued to re-emerge sporadically in Bangladesh and Australia, respectively. There are currently no therapeutics or vaccines available to treat Henipavirus infection and both are classified as BSL4 pathogens. RNA interference (RNAi) is a process by which double-stranded RNA directs sequence-specific degradation of messenger RNA in animal and plant cells. Small interfering RNAs (siRNAs) mediate RNAi by inhibiting gene expression of homologous mRNA and our preliminary studies suggest RNAi may be a useful approach to developing novel therapies for these highly lethal pathogens. Eight NiV siRNA molecules (four L and four N gene specific), two HeV N gene specific, and two non-specific control siRNA molecules were designed and tested for their ability to inhibit a henipavirus minigenome replication system (which does not require the use of live virus) in addition to live virus infections in vitro. In the minigenome assay three out of the four siRNAs that targeted the L gene of NiV effectively inhibited replication. In contrast, only NiV N gene siRNAs were effective in reducing live NiV replication, suggesting inhibition of early, abundantly expressed gene transcripts may be more effective than later, less abundant transcripts. Additionally, some of the siRNAs effective against NiV infection were only partially effective inhibitors of HeV infection. An inverse correlation between the number of nucleotide mismatches and the efficacy of siRNA inhibition was observed. The demonstration that RNAi effectively inhibits henipavirus replication in vitro, is a novel approach and may provide an effective therapy for these highly lethal, zoonotic pathogens.

  1. Pyrilamine inhibits nicotine-induced catecholamine secretion.

    PubMed

    Kim, Dong-Chan; Yun, So Jeong; Park, Yong-Soo; Jun, Dong-Jae; Kim, Dongjin; Jiten Singh, N; Kim, Sanguk; Kim, Kyong-Tai

    2014-07-01

    Function of nicotine, which induces activation of all parts of the body including our brain, has been receiving much attention for a long period of time and also been actively studied by researchers for its pharmacological actions in the central nervous system. The modulation of nicotine concentration and the inhibition of nicotine binding on target receptors in the brain are the key factors for smoking addiction therapy. In previous studies showed that influx of nicotine at the blood-brain barrier was through the pyrilamine-sensitive organic cation transporters. But the direct interacting mechanism of pyrilamine on the nicotine binding target receptors has not yet been clarified. The aim of the present study is to investigate the direct binding mechanisms of a pyrilamine on the nicotinic acetylcholine receptors (nAChRs). We found that pyrilamine shares the same ligand binding pocket of nicotine (NCT) on nAChRs but interacts with more amino acid residues than NCT does. The extended part of pyrilamine interacts with additional residues in the ligand binding pocket of nAChRs which are located nearby the entrance of the binding pocket. The catecholamine (CA) secretion induced by nAChR agonist (NCT') was significantly inhibited by the pyrilamine pretreatment. Real time carbon-fiber amperometry confirmed the inhibition of the NCT'-induced exocytosis by pyrilamine in a single cell level. We also found that pyrilamine inhibited the NCT'-induced [Ca(2+)]i. In contrast, pyrilamine did not affect the increase in calcium induced by high K(+). Overall, these data suggest that pyrilamine directly docks into the ligand binding site of nAChRs and specifically inhibits the nAChR-mediated effects thereby causing inhibition of CA secretion. Therefore, pyrilamine may play an important role to explore new treatments to aid smoking cessation.

  2. DNA-Targeted Inhibition of MGMT.

    PubMed

    Luedtke, Nathan William; Marsoner, Theodor; Schmidt, Olivia; Trimer, Therese

    2017-02-08

    The cationic porphyrin 5,10,15,20-tetrakis (diisopropyl-guanidine)-21H,23H-porphine "DIGPor" selectively binds to DNA containing O6-methylguanine (O6-MeG) and inhibits the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT). The O6-MeG selectivity and MGMT inhibitory activity of DIGPor was improved by incorporating ZnII into the porphyrin. The resulting metal complex "Zn-DIGPor" potentiated the activity of the DNA alkylating drug temozolomide in an MGMT-expressing cell line. To the best of our knowledge, these results provide the first examples of DNA-targeted MGMT inhibition.

  3. Inhibition of aflatoxin formation by some spices.

    PubMed

    Mabrouk, S S; El-Shayeb, N M

    1980-01-01

    The effects of black pepper, cinnamon, peppermint, cumin, ginger and clove on growth and aflatoxin formation of Aspergillus flavus were studied in rice powdercorn steep (RC) medium. The effects of the first five spices were judged to be inhibition of aflatoxin formation rather than of mycelial growth. Clove completely inhibited both mycelial growth and aflatoxin formation at a concentration above 0.1%. No aflatoxin was produced when cumin and mint levels of 5% and 10% were used. Black pepper and ginger levels of 10% decreased aflatoxin formation by 100%. Higher concentrations of cinnamon, mint, cumin and ginger stimulated mycelial growth.

  4. Bacterial contact-dependent growth inhibition (CDI)

    PubMed Central

    Ruhe, Zachary C.; Low, David A.; Hayes, Christopher S.

    2013-01-01

    Bacteria cooperate to form multicellular communities and compete against one another for environmental resources. Here, we review recent advances in our understanding of bacterial competition mediated by contact-dependent growth inhibition (CDI) systems. Different CDI+ bacteria deploy a variety of toxins to inhibit neighboring cells and protect themselves from autoinhibition by producing specific immunity proteins. The genes encoding CDI toxin–immunity pairs appear to be exchanged between cdi loci and are often associated with other toxin-delivery systems in diverse bacteria. CDI also appears to facilitate cooperative behavior between kin, suggesting that these systems may have other roles beyond competition. PMID:23473845

  5. Rust inhibiting additive compositions for oils

    SciTech Connect

    Haugen, H.

    1980-09-23

    Compositions which include mixtures of a calcium hydroxide overbased oil-soluble calcium sulfonate, hexylene glycol and a surfactant consisting of an ethoxylated aliphatic amine, particularly, diethoxylated cocoamine or diethoxylated soyamine, are useful as rust inhibiting additives for oils and the like. By incorporating these compositions in petroleum based oils such as petroleum based oils of lubricating oil quality which come into contact with metal surfaces under conditions such that the metal surfaces tend to rust or otherwise be subject to deterioration it is possible to inhibit rust formation on such metal surfaces.

  6. Porphyrin-based compounds exert antibacterial action against the sexually transmitted pathogens Neisseria gonorrhoeae and Haemophilus ducreyi.

    PubMed

    Bozja, J; Yi, K; Shafer, W M; Stojiljkovic, I

    2004-12-01

    A series of porphyrin based compounds without (nMP) or with (MP) metals were found to have potent bactericidal action in vitro against the sexually transmitted pathogens Neisseria gonorrhoeae and Haemophilus ducreyi. nMP and MP did not show bactericidal activity against five species of lactobacilli. An MP containing gallium had the capacity to block a gonococcal infection in a murine vaginal model, indicating that its development as a topical microbicide to block sexually transmitted bacterial infections is warranted. In contrast to other bacterial species, loss of the gonococcal haemoglobin uptake system encoded by hpuB or energy supplied through the TonB-ExbB-ExbD system did not significantly affect levels of MP-susceptibility in gonococci. In contrast, mutations in gonococci that inactivate the mtrCDE-encoded efflux pump were found to enhance gonococcal susceptibility to nMPs and MPs while over-production of this efflux pump decreased levels of gonococcal susceptibility to these compounds.

  7. A quick method for the determination of inhibition constants.

    PubMed Central

    Waley, S G

    1982-01-01

    The inhibition constant Ki in the common case of competitive inhibition can be obtained by simple comparison of progress curves in the presence and in the absence of inhibitor. The difference between the times taken for the concentration of substrate to fall to the same value is used to obtain Ki. The procedure to use when the product inhibits is described. When there is mixed inhibition, reactions at different substrate concentrations are used to obtain both inhibition constants. PMID:7150236

  8. Lipophilic chelator inhibition of electron transport in Escherichia coli.

    PubMed Central

    Crane, R T; Sun, I L; Crane, F L

    1975-01-01

    The lipophilic chelator bathophenanthroline inhibits electron transport in membranes from Escherichia coli. The less lipophilic 1,10-phenanthroline, bathophenanthroline sulfonate, and alpha,alpha-dipyridyl have little effect. Reduced nicotinamide adenine dinucleotide oxidase is more sensitive to bathophenanthroline inhibition than lactate oxidase activity. Evidence for two sites of inhibition comes from the fact that both reduced nicotinamide adenine dinucleotide menadione reductase and duroquinol oxidase activities are inhibited. Addition of uncouplers of phosphorylation before bathophenanthroline protects against inhibition. PMID:1092663

  9. Target Predictability, Sustained Attention, and Response Inhibition

    ERIC Educational Resources Information Center

    Carter, Leonie; Russell, Paul N.; Helton, William S.

    2013-01-01

    We examined whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed a number detection task for 37.3 min using either a Sustained Attention to Response Task (SART; high Go low No-Go) or a more traditionally formatted vigilance task (TFT; high No-Go low Go) response…

  10. Nickel inhibits mitochondrial fatty acid oxidation.

    PubMed

    Uppala, Radha; McKinney, Richard W; Brant, Kelly A; Fabisiak, James P; Goetzman, Eric S

    2015-08-07

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation-the pathway by which fatty acids are catabolized for energy-in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with l-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 h), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis.

  11. Aromatase Inhibition in a Transcriptional Network Context

    EPA Science Inventory

    A variety of chemicals in the environment have the potential to inhibit aromatase, an enzyme critical to estrogen synthesis. We examined the responses of female fathead minnow ovaries (FHM, Pimephales promelas) to a model aromatase inhibitor, fadrozole, using a transcriptional ne...

  12. Nitrite inhibition of denitrification by Pseudomonas fluorescens

    SciTech Connect

    Almeida, J.S.; Julio, S.M.; Reis, M.A.M. |

    1995-05-05

    Using a pure culture of Pseudomonas fluorescens as a model system nitrite inhibition of denitrification was studied. A mineral media with acetate and nitrate as sole electron donor and acceptor, respectively, was used. Results obtained in continuous stirred-tank reactors (CSTR) operated at pH values between 6.6 and 7.8 showed that growth inhibition depended only on the nitrite undissociated fraction concentration (nitrous acid). A mathematical model to describe this dependence is put forward. The maximum nitrous acid concentration compatible with cell growth and denitrification activity was found to be 66 {mu}g N/L. Denitrification activity was partially associated with growth, as described by the Luedeking-Piret equation. However, when the freshly inoculated reactor was operated discontinuously, nitrite accumulation caused growth uncoupling from denitrification activity. The authors suggest that these results can be interpreted considering that (a) nitrous acid acts as a proton uncoupler; and (b) cultures continuously exposed to nitrous acid prevent the uncoupling effect but not the growth inhibition. Examination of the growth dependence on nitrite concentration at pH 7.0 showed that adapted cultures (growth on CSTR) are less sensitive to nitrous acid inhibition than the ones cultivated in batch.

  13. Epoxygenated Fatty Acids Inhibit Retinal Vascular Inflammation

    PubMed Central

    Capozzi, Megan E.; Hammer, Sandra S.; McCollum, Gary W.; Penn, John S.

    2016-01-01

    The objective of the present study was to assess the effect of elevating epoxygenated fatty acids on retinal vascular inflammation. To stimulate inflammation we utilized TNFα, a potent pro-inflammatory mediator that is elevated in the serum and vitreous of diabetic patients. In TNFα-stimulated primary human retinal microvascular endothelial cells, total levels of epoxyeicosatrienoic acids (EETs), but not epoxydocosapentaenoic acids (EDPs), were significantly decreased. Exogenous addition of 11,12-EET or 19,20-EDP when combined with 12-(3-adamantane-1-yl-ureido)-dodecanoic acid (AUDA), an inhibitor of epoxide hydrolysis, inhibited VCAM-1 and ICAM-1 expression and protein levels; conversely the diol product of 19,20-EDP hydrolysis, 19,20-DHDP, induced VCAM1 and ICAM1 expression. 11,12-EET and 19,20-EDP also inhibited leukocyte adherence to human retinal microvascular endothelial cell monolayers and leukostasis in an acute mouse model of retinal inflammation. Our results indicate that this inhibition may be mediated through an indirect effect on NFκB activation. This is the first study demonstrating a direct comparison of EET and EDP on vascular inflammatory endpoints, and we have confirmed a comparable efficacy from each isomer, suggesting a similar mechanism of action. Taken together, these data establish that epoxygenated fatty acid elevation will inhibit early pathology related to TNFα-induced inflammation in retinal vascular diseases. PMID:27966642

  14. Inhibiting Intuitive Thinking in Mathematics Education

    ERIC Educational Resources Information Center

    Thomas, Michael O. J.

    2015-01-01

    The papers in this issue describe recent collaborative research into the role of inhibition of intuitive thinking in mathematics education. This commentary reflects on this research from a mathematics education perspective and draws attention to some of the challenges that arise in collaboration between research fields with different cultures,…

  15. Hemagglutinin inhibition assay with swine sera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hemagglutination is based on the ability of certain viruses to agglutinate red blood cells (RBC) of certain animal species by formation of cross-linking lattices between RBC. Antibodies that have the ability to inhibit the hemagglutination property of influenza A viruses are generally thought to pro...

  16. Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis

    SciTech Connect

    Szkudlarek-Mikho, Maria; Saunders, Rudel A.; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Salinomycin inhibits preadipocyte differentiation into adipocytes. Black-Right-Pointing-Pointer Salinomycin inhibits transcriptional regulation of adipogenesis. Black-Right-Pointing-Pointer Pharmacological effects of salinomycin suggest toxicity in cancer therapy. -- Abstract: The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor {gamma}. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy.

  17. Factors Inhibiting Hispanic Parents' School Involvement

    ERIC Educational Resources Information Center

    Smith, Jay; Stern, Kenneth; Shatrova, Zhanna

    2008-01-01

    Factors inhibiting Hispanic parental involvement in non-metropolitan area schools were studied. With the mandates of No Child Left Behind intensifying the need to improve the academic achievement of all at-risk groups of students in American schools, and with the relatively new phenomenon of large numbers of Hispanics settling in non-metropolitan…

  18. The Mechanism Underlying Inhibition of Saccadic Return

    ERIC Educational Resources Information Center

    Ludwig, Casimir J. H.; Farrell, Simon; Ellis, Lucy A.; Gilchrist, Iain D.

    2009-01-01

    Human observers take longer to re-direct gaze to a previously fixated location. Although there has been some exploration of the characteristics of inhibition of saccadic return (ISR), the exact mechanisms by which ISR operates are currently unknown. In the framework of accumulation models of response times, in which evidence is integrated over…

  19. Temporal Preparation, Response Inhibition and Impulsivity

    ERIC Educational Resources Information Center

    Correa, Angel; Trivino, Monica; Perez-Duenas, Carolina; Acosta, Alberto; Lupianez, Juan

    2010-01-01

    Temporal preparation and impulsivity involve overlapping neural structures (prefrontal cortex) and cognitive functions (response inhibition and time perception), however, their interrelations had not been investigated. We studied such interrelations by comparing the performance of groups with low vs. high non-clinical trait impulsivity during a…

  20. Motivational Influences on Response Inhibition Measures

    ERIC Educational Resources Information Center

    Leotti, Lauren A.; Wager, Tor D.

    2010-01-01

    Psychological research has placed great emphasis on inhibitory control due to its integral role in normal cognition and clinical disorders. The stop-signal task and associated measure--stop-signal reaction time (SSRT)--provides a well-established paradigm for measuring response inhibition. However, motivational influences on stop-signal…

  1. Resveratrol inhibits polyphosphoinositide metabolism in activated platelets.

    PubMed

    Olas, Beata; Wachowicz, Barbara; Holmsen, Holm; Fukami, Miriam H

    2005-08-15

    The effects of resveratrol (trans-3,4',5-trihydroxystilbene) on activation responses and the polyphosphoinositide metabolism in human blood platelets have been studied. Resveratrol partially inhibited secretory responses (liberation of dense granule nucleotides and lysosomal acid hydrolases), microparticle formation and protein phosphorylations induced by thrombin. The effects of resveratrol on phosphoinositide metabolites, phosphatidate (PtdOH), phosphatidylinositol (PtdIns), phosphatidylinositol-4-phosphate (PtdIns-4(5)-P), phosphatidylinositol 4,5-bisphosphate (PtdIns-4,5-P2), phosphatidylinositol-3,4-bisphosphate (PtdIns-3,4-P2) and phosphatidylinositol-3,4,5-trisphosphate (PtdIns-3,4,5-P3) were monitored in blood platelets prelabelled with [32P]Pi. Resveratrol not only inhibited the marked increase in levels of PtdOH in platelets activated by thrombin (0.1 U/ml) but it decreased the steady state levels of the other polyphosphoinositide metabolites. The distribution of 32P in phosphoinositides in activated platelets was consistent with inhibition of CDP-DAG inositol transferase and a weak inhibition of PtdIns-4(5)-P kinase. These observations show that resveratrol has a profound effect on phospholipids, particularly on polyphosphoinositide metabolism, and may decrease the amount of PtdIns-4,5-P2 available for signalling in these cells.

  2. Temporal preparation, response inhibition and impulsivity.

    PubMed

    Correa, Angel; Triviño, Mónica; Pérez-Dueñas, Carolina; Acosta, Alberto; Lupiáñez, Juan

    2010-08-01

    Temporal preparation and impulsivity involve overlapping neural structures (prefrontal cortex) and cognitive functions (response inhibition and time perception), however, their interrelations had not been investigated. We studied such interrelations by comparing the performance of groups with low vs. high non-clinical trait impulsivity during a temporal preparation go no-go task. This task measured, in less than 10 min, how response inhibition was influenced both by temporal orienting of attention (guided by predictive temporal cues) and by sequential effects (produced by repetition/alternation of the duration of preparatory intervals in consecutive trials). The results showed that sequential effects produced dissociable patterns of temporal preparation as a function of impulsivity. Sequential effects facilitated both response speed (reaction times - RTs - to the go condition) and response inhibition (false alarms to the no-go condition) selectively in the low impulsivity group. In the high impulsivity group, in contrast, sequential effects only improved RTs but not response inhibition. We concluded that both excitatory and inhibitory processing may be enhanced concurrently by sequential effects, which enables the temporal preparation of fast and controlled responses. Impulsivity could hence be related to less efficient temporal preparation of that inhibitory processing.

  3. Illustrating Enzyme Inhibition Using Gibbs Energy Profiles

    ERIC Educational Resources Information Center

    Bearne, Stephen L.

    2012-01-01

    Gibbs energy profiles have great utility as teaching and learning tools because they present students with a visual representation of the energy changes that occur during enzyme catalysis. Unfortunately, most textbooks divorce discussions of traditional kinetic topics, such as enzyme inhibition, from discussions of these same topics in terms of…

  4. Neprilysin inhibition in chronic kidney disease

    PubMed Central

    Judge, Parminder; Haynes, Richard; Landray, Martin J.; Baigent, Colin

    2015-01-01

    Despite current practice, patients with chronic kidney disease (CKD) are at increased risk of progression to end-stage renal disease and cardiovascular events. Neprilysin inhibition (NEPi) is a new therapeutic strategy with potential to improve outcomes for patients with CKD. NEPi enhances the activity of natriuretic peptide systems leading to natriuresis, diuresis and inhibition of the renin–angiotensin system (RAS), which could act as a potentially beneficial counter-regulatory system in states of RAS activation such as chronic heart failure (HF) and CKD. Early NEPi drugs were combined with angiotensin-converting enzyme inhibitors but were associated with unacceptable rates of angioedema and, therefore, withdrawn. However, one such agent (omapatrilat) showed promise of NEP/RAS inhibition in treating CKD in animal models, producing greater reductions in proteinuria, glomerulosclerosis and tubulointerstitial fibrosis compared with isolated RAS inhibition. A new class of drug called angiotensin receptor neprilysin inhibitor (ARNi) has been developed. One such drug, LCZ696, has shown substantial benefits in trials in hypertension and HF. In CKD, HF is common due to a range of mechanisms including hypertension and structural heart disease (including left ventricular hypertrophy), suggesting that ARNi could benefit patients with CKD by both retarding the progression of CKD (hence delaying the need for renal replacement therapy) and reducing the risk of cardiovascular disease. LCZ696 is now being studied in a CKD population. PMID:25140014

  5. Neprilysin inhibition in chronic kidney disease.

    PubMed

    Judge, Parminder; Haynes, Richard; Landray, Martin J; Baigent, Colin

    2015-05-01

    Despite current practice, patients with chronic kidney disease (CKD) are at increased risk of progression to end-stage renal disease and cardiovascular events. Neprilysin inhibition (NEPi) is a new therapeutic strategy with potential to improve outcomes for patients with CKD. NEPi enhances the activity of natriuretic peptide systems leading to natriuresis, diuresis and inhibition of the renin-angiotensin system (RAS), which could act as a potentially beneficial counter-regulatory system in states of RAS activation such as chronic heart failure (HF) and CKD. Early NEPi drugs were combined with angiotensin-converting enzyme inhibitors but were associated with unacceptable rates of angioedema and, therefore, withdrawn. However, one such agent (omapatrilat) showed promise of NEP/RAS inhibition in treating CKD in animal models, producing greater reductions in proteinuria, glomerulosclerosis and tubulointerstitial fibrosis compared with isolated RAS inhibition. A new class of drug called angiotensin receptor neprilysin inhibitor (ARNi) has been developed. One such drug, LCZ696, has shown substantial benefits in trials in hypertension and HF. In CKD, HF is common due to a range of mechanisms including hypertension and structural heart disease (including left ventricular hypertrophy), suggesting that ARNi could benefit patients with CKD by both retarding the progression of CKD (hence delaying the need for renal replacement therapy) and reducing the risk of cardiovascular disease. LCZ696 is now being studied in a CKD population.

  6. Cyclosporine inhibits macrophage-mediated antigen presentation

    SciTech Connect

    Ziegler, H.K.; Palay, D.; Wentworth, P.; Cluff, C.

    1986-03-01

    The influence of cyclosporine on antigen-specific, macrophage-dependent T cell activation was analyzed in vitro. Murine T cell activation by antigens derived from Listeria monocytogenes was monitored by the production of interleukin-2. Pretreatment (2 hrs., 37/sup 0/C) of macrophages with cyclosporine resulted in a population of macrophages with a markedly diminished capacity to support the activation of T lymphocytes. When cyclosporine-pretreated macrophages were added to cultures of antigen and untreated T cells, the dose of cyclosporine which produced 50% inhibition was 1.5 ..mu..g/ml. Appropriate control experiments indicated that cyclosporine was indeed inhibiting at the macrophage level. The addition of interleukin-1 or indomethacin to the cultures did not alter the inhibitory effect of cyclosporine. Under conditions which produced >90% inhibition of antigen presentation, macrophage surface Ia expression was not altered, and the uptake and catabolism of radiolabelled antigen was normal. Thus, cyclosporine inhibits antigen presentation by a mechanism which appears unrelated to changes in Il-1 elaboration, prostaglandin production, Ia expression, or antigen uptake and catabolism.

  7. [The inhibition of potato tubers wound reparation].

    PubMed

    Chalenko, G I; Vasiukova, N I; Gerasimova, N G; Ozeretskovskaia, O l

    2009-01-01

    The multiple washing of the wound surface of potato tubers by water adversely affected the protective properties of wound periderm. Immune inhibitor beta-1,3-beta-1,6 glucan had a property of local effect and inhibited the process of wound healing. The pentasaccharide of xyloglucan caused necrosis of potato tuber tissue and prevented the wound reparation process.

  8. Sphingolipids inhibit vimentin-dependent cell migration.

    PubMed

    Hyder, Claire L; Kemppainen, Kati; Isoniemi, Kimmo O; Imanishi, Susumu Y; Goto, Hidemasa; Inagaki, Masaki; Fazeli, Elnaz; Eriksson, John E; Törnquist, Kid

    2015-06-01

    The sphingolipids, sphingosine 1-phosphate (S1P) and sphingosylphosphorylcholine (SPC), can induce or inhibit cellular migration. The intermediate filament protein vimentin is an inducer of migration and a marker for epithelial-mesenchymal transition. Given that keratin intermediate filaments are regulated by SPC, with consequences for cell motility, we wanted to determine whether vimentin is also regulated by sphingolipid signalling and whether it is a determinant for sphingolipid-mediated functions. In cancer cells where S1P and SPC inhibited migration, we observed that S1P and SPC induced phosphorylation of vimentin on S71, leading to a corresponding reorganization of vimentin filaments. These effects were sphingolipid-signalling-dependent, because inhibition of either the S1P2 receptor (also known as S1PR2) or its downstream effector Rho-associated kinase (ROCK, for which there are two isoforms ROCK1 and ROCK2) nullified the sphingolipid-induced effects on vimentin organization and S71 phosphorylation. Furthermore, the anti-migratory effect of S1P and SPC could be prevented by expressing S71-phosphorylation-deficient vimentin. In addition, we demonstrated, by using wild-type and vimentin-knockout mouse embryonic fibroblasts, that the sphingolipid-mediated inhibition of migration is dependent on vimentin. These results imply that this newly discovered sphingolipid-vimentin signalling axis exerts brake-and-throttle functions in the regulation of cell migration.

  9. Serum amyloid P inhibits dermal wound healing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The repair of open wounds depends on granulation tissue formation and contraction, which is primarily mediated by myofibroblasts. A subset of myofibroblasts originates from bone-marrow-derived monocytes which differentiate into fibroblast-like cells called fibrocytes. Serum amyloid P (SAP) inhibits ...

  10. Search Asymmetry, Sustained Attention, and Response Inhibition

    ERIC Educational Resources Information Center

    Stevenson, Hugh; Russell, Paul N.; Helton, William S.

    2011-01-01

    In the present experiment, we used search asymmetry to test whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed feature present and feature absent target detection tasks using either a sustained attention to response task (SART; high Go low No-Go) or a…

  11. Nickel Inhibits Mitochondrial Fatty Acid Oxidation

    PubMed Central

    Uppala, Radha; McKinney, Richard W.; Brant, Kelly A.; Fabisiak, James P.; Goetzman, Eric S.

    2015-01-01

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation—the pathway by which fatty acids are catabolized for energy—in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with L-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 hr), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis. PMID:26051273

  12. Auditory and audiovisual inhibition of return.

    PubMed

    Spence, C; Driver, J

    1998-01-01

    Two experiments examined any inhibition-of-return (IOR) effects from auditory cues and from preceding auditory targets upon reaction times (RTs) for detecting subsequent auditory targets. Auditory RT was delayed if the preceding auditory cue was on the same side as the target, but was unaffected by the location of the auditory target from the preceding trial, suggesting that response inhibition for the cue may have produced its effects. By contrast, visual detection RT was inhibited by the ipsilateral presentation of a visual target on the preceding trial. In a third experiment, targets could be unpredictably auditory or visual, and no peripheral cues intervened. Both auditory and visual detection RTs were now delayed following an ipsilateral versus contralateral target in either modality on the preceding trial, even when eye position was monitored to ensure central fixation throughout. These data suggest that auditory target-target IOR arises only when target modality is unpredictable. They also provide the first unequivocal evidence for cross-modal IOR, since, unlike other recent studies (e.g., Reuter-Lorenz, Jha, & Rosenquist, 1996; Tassinari & Berlucchi, 1995; Tassinari & Campara, 1996), the present cross-modal effects cannot be explained in terms of response inhibition for the cue. The results are discussed in relation to neurophysiological studies and audiovisual links in saccade programming.

  13. BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL TROPHOBLAST DIFFERENTIATION

    EPA Science Inventory

    BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL
    TROPHOBLAST DIFFERENTIATION
    Jiangang Chen, Twanda L. Thirkill, Peter N. Lohstroh, Susan R. Bielmeier, Michael
    G. Narotsky, Deborah S. Best, Randy A. Harrison, Kala Natarajan, Rex A. Pegram,
    Bill L. Lasley, and Gordon C. Do...

  14. Inhibition of human aromatase by myosmine.

    PubMed

    Doering, Irene L; Richter, Elmar

    2009-04-01

    Myosmine, a minor tobacco alkaloid widely occurring in food products of plant and animal origin, inhibits the conversion of testosterone to estradiol by human aromatase (IC(50): 33+/-2 microM) sevenfold more potent than nicotine (IC(50): 223+/-10 microM) and may have implications for sexual hormone homoeostasis.

  15. Fullerene nanomaterials inhibit the allergic response.

    PubMed

    Ryan, John J; Bateman, Henry R; Stover, Alex; Gomez, Greg; Norton, Sarah K; Zhao, Wei; Schwartz, Lawrence B; Lenk, Robert; Kepley, Christopher L

    2007-07-01

    Fullerenes are a class of novel carbon allotropes that may have practical applications in biotechnology and medicine. Human mast cells (MC) and peripheral blood basophils are critical cells involved in the initiation and propagation of several inflammatory conditions, mainly type I hypersensitivity. We report an unanticipated role of fullerenes as a negative regulator of allergic mediator release that suppresses Ag-driven type I hypersensitivity. Human MC and peripheral blood basophils exhibited a significant inhibition of IgE dependent mediator release when preincubated with C(60) fullerenes. Protein microarray demonstrated that inhibition of mediator release involves profound reductions in the activation of signaling molecules involved in mediator release and oxidative stress. Follow-up studies demonstrated that the tyrosine phosphorylation of Syk was dramatically inhibited in Ag-challenged cells first incubated with fullerenes. In addition, fullerene preincubation significantly inhibited IgE-induced elevation in cytoplasmic reactive oxygen species levels. Furthermore, fullerenes prevented the in vivo release of histamine and drop in core body temperature in vivo using a MC-dependent model of anaphylaxis. These findings identify a new biological function for fullerenes and may represent a novel way to control MC-dependent diseases including asthma, inflammatory arthritis, heart disease, and multiple sclerosis.

  16. Behavioral Inhibition in Children with Learning Disabilities

    ERIC Educational Resources Information Center

    De Weerdt, Frauke; Desoete, Annemie; Roeyers, Herbert

    2013-01-01

    Children with reading disabilities (RD, n = 17), mathematical disabilities (MD, n = 22), combined reading and mathematical disabilities (RD + MD, n = 28) and control peers (n = 45) were tested on behavioral inhibition with a Go/no-go task in a picture, letter and digit-modality. In contrast to children without RD, children with RD made…

  17. Curcumin inhibition of angiogenesis and adipogenesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The growth of new blood vessels or angiogenesis is necessary for the growth of adipose tissue. Adipokines produced by fat cells stimulate this process. Some dietary polyphenols with antiangiogenic activity may suppress adipose tissue growth not only by inhibiting angiogenesis, but also by interferin...

  18. Aqueous rust-inhibiting and lubricating compositions

    SciTech Connect

    Brandolese, E.

    1983-06-14

    Rust-inhibiting compounds, especially for aqueous systems such as tool-lubricating emulsions for machine tools and which consist of amine salts of a number of monoaminoalkylene dicarboxylic acids are disclosed. These rust-inhibitors are used in combination with water and an alkanolamine. Examples and test results are given.

  19. Inhibited interferon production after space flight

    NASA Technical Reports Server (NTRS)

    Sonnenfeld, G.; Gould, C. L.; Williams, J.; Mandel, A. D.

    1988-01-01

    Several studies have been performed in our laboratories indicating that interferon production may be impaired in rodents after space flight. Using an antiorthostatic suspension model that simulates some of the effects of microgravity seen during space flight, we have shown that interferon-alpha/beta production was inhibited. The inhibition was not due solely to the stress of suspension. The inhibited interferon production was transient, as suspended animals returned to normal caging recovered the ability to produce interferon. Antiorthostatic suspension of mice also resulted in a loss of resistance to infection with the diabetogenic strain of encephalomyocarditis virus, which correlated with the drop in interferon production. In rats flown in US Space Shuttle mission SL-3, interferon-gamma production was inhibited severely when spleen cells were challenged with concanavalin-A upon return to earth. In contrast, interleukin-3 production by these cells was normal. These results suggest that immune responses may be altered after antiorthostatic modeling or space flight, and the resistance to viral infections may be especially affected.

  20. Inhibition of cellulase by fermentation products

    SciTech Connect

    Takagi, M.

    1984-12-01

    Cellulosic materials are important resources for the production of fuels and chemicals. One of the processes designed to utilize cellulosic materials is enzymatic hydrolysis followed by fermentation to final products. It was shown that simultaneous saccharification and fermentation (SSF) is effective in the production of ethanol from cellulose. The acceleration of the rate of cellulose degradation in SSF was caused by less inhibition of cellulase by ethanol than by glucose and/or cellobiose. In order to apply the SSF method effectively to the production of substances derived from glucose by fermentation, several conditions should be satisfied. One of them is the coincidence of conditions of enzymatic hydrolysis and fermentation of hydrolyzate, such as pH and temperature. The second condition is that the inhibition of cellulase by the final product is less than that by glucose and/or cellobiose. There has been a comprehensive review and some reports on inhibition of cellulase by saccharides such as glucose, cellobiose, xylose, lactose, maltose, metals, and some chemicals such as dyes, detergents, halogenated compounds, and phenolic compounds. In this communication, the inhibition of cellulase by several substances derived by fermentation of glucose is reported. 7 references.

  1. Gold Nanoparticles Inhibit Matrix Metalloproteases without Cytotoxicity.

    PubMed

    Hashimoto, M; Sasaki, J I; Yamaguchi, S; Kawai, K; Kawakami, H; Iwasaki, Y; Imazato, S

    2015-08-01

    Nanoparticles (NPs) are currently the focus of considerable attention for dental applications; however, their biological effects have not been fully elucidated. The long-term, slow release of matrix metalloproteases (MMPs) digests collagen fibrils within resin-dentin bonds. Therefore, MMP inhibitors can prolong the durability of resin-dentin bonds. However, there have been few reports evaluating the combined effect of MMP inhibition and the cytotoxic effects of NPs for dentin bonding. The aim of this study was to evaluate MMP inhibition and cytotoxic responses to gold (AuNPs) and platinum nanoparticles (PtNPs) stabilized by polyvinylpyrrolidone (PVP) in cultured murine macrophages (RAW264) by using MMP inhibition assays, measuring cell viability and inflammatory responses (quantitative reverse transcription polymerase chain reaction [RT-qPCR]), and conducting a micromorphological analysis by fluorescence and transmission electron microscopy. Cultured RAW264 cells were exposed to metal NPs at various concentrations (1, 10, 100, and 400 µg/mL). AuNPs and PtNPs markedly inhibited MMP-8 and MMP-9 activity. Although PtNPs were cytotoxic at high concentrations (100 and 400 µg/mL), no cytotoxic effects were observed for AuNPs at any concentration. Transmission electron microscopy images showed a significant nonrandom intercellular distribution for AuNPs and PtNPs, which were mostly observed to be localized in lysosomes but not in the nucleus. RT-qPCR analysis demonstrated inflammatory responses were not induced in RAW264 cells by AuNPs or PtNPs. The cytotoxicity of nanoparticles might depend on the core metal composition and arise from a "Trojan horse" effect; thus, MMP inhibition could be attributed to the surface charge of PVP, which forms the outer coating of NPs. The negative charge of the surface coating of PVP binds to Zn(2+) from the active center of MMPs by chelate binding and results in MMP inhibition. In summary, AuNPs are attractive NPs that effectively

  2. Inhibition of lung tumorigenesis by tea.

    PubMed

    Yang, Chung S; Liao, Jie; Yang, Guang-yu; Lu, Gary

    2005-01-01

    Tea and tea constituents have been shown by different investigators to inhibit lung tumorigenesis in different animal model systems. This includes lung tumorigenesis in A/J mice induced by 4-(methylnitrosamino)-1-(3pyridyl)-1-butanone (NNK), N-nitrosodiethylamine, benzo[a]pyrene, N-nitrosomethylurea, or cisplatin. Inhibition of lung tumorigenesis has also been demonstrated in C3H mice treated with N-nitrosodiethylamine. In most of these experiments, reduction in tumor number and tumor size has been observed in the tea-treated group, and in some experiments, decreased tumor incidence has also been observed. The green tea constituent, epigallocatechin-3-gallate (EGCG), and the black tea constituent, theaflavins, have also been shown to be effective. Black tea preparations have been shown to reduce the incidence and number of spontaneously generated lung adenocarcinomas and rhabdomyosarcoma in A/J mice, as well as inhibit the progression of lung adenoma to adenocarcinoma. The mechanisms for the inhibitory action have not been well elucidated. It may be related to the antiproliferative, proapoptotic, and antiangiogenic activities of tea constituents that have been demonstrated in some experiments. These activities may be a result of the inhibition of key protein kinases involved in signal transduction and cell cycle regulation. Tea catechins, such as EGCG, have been suggested to be the effective components. However, a study suggests that caffeine is the key effective constituent for the inhibitory activity of lung tumorigenesis in Fisher 344 rats by black tea. In many of the experiments, tea consumption resulted in the reduction of body fat and body weight; these factors may also contribute to the inhibition of tumorigenesis.

  3. Cisplatin inhibits MEK1/2

    PubMed Central

    Yamamoto, Tetsu; Tsigelny, Igor F.; Götz, Andreas W.; Howell, Stephen B.

    2015-01-01

    Cisplatin (cDDP) is known to bind to the CXXC motif of proteins containing a ferrodoxin-like fold but little is known about its ability to interact with other Cu-binding proteins. MEK1/2 has recently been identified as a Cu-dependent enzyme that does not contain a CXXC motif. We found that cDDP bound to and inhibited the activity of recombinant MEK1 with an IC50 of 0.28 μM and MEK1/2 in whole cells with an IC50 of 37.4 μM. The inhibition of MEK1/2 was relieved by both Cu+1 and Cu+2 in a concentration-dependent manner. cDDP did not inhibit the upstream pathways responsible for activating MEK1/2, and did not cause an acute depletion of cellular Cu that could account for the reduction in MEK1/2 activity. cDDP was found to bind MEK1/2 in whole cells and the extent of binding was augmented by supplementary Cu and reduced by Cu chelation. Molecular modeling predicts 3 Cu and cDDP binding sites and quantum chemistry calculations indicate that cDDP would be expected to displace Cu from each of these sites. We conclude that, at clinically relevant concentrations, cDDP binds to and inhibits MEK1/2 and that both the binding and inhibitory activity are related to its interaction with Cu bound to MEK1/2. This may provide the basis for useful interactions of cDDP with other drugs that inhibit MAPK pathway signaling. PMID:26155939

  4. Antiretrovirals inhibit arginase in human microglia.

    PubMed

    Lisi, Lucia; Laudati, Emilia; Miscioscia, Teresa F; Dello Russo, Cinzia; Topai, Alessandra; Navarra, Pierluigi

    2016-01-01

    Preliminary evidence in an animal model, that is, primary cultures of rat microglia cells, suggested that some antiretroviral drugs (ARVs), namely darunavir, atazanavir, efavirenz, and nevirapine, increase NO production through a mechanism involving the inhibition of arginase (ARG) activity. This study was conceived to investigate the effects of ARVs on ARG activity in a human experimental model. We compared CHME-5 human microglial immortalized cells under basal conditions with cells exposed to either IL-4, a mix of inflammatory cytokines, or both stimuli given together. We also tested the effects of ARVs on CHME-5 cell lysates after exposure to the above stimuli. Moreover, the interaction between the ARVs and ARG was investigated via computational chemistry. We found that ARVs consistently inhibit ARG activity both in intact and lysed cells. In docking studies, darunavir and atazanavir showed similar scores compared with both l-arginine and the ARG antagonist nor-NOHA. Efavirenz and nevirapine, which are less potent in inhibiting ARG in the biochemical assay, also had lower scores. In conclusion, the present findings in a human model support the notion that ARG pathway can present a new, additional molecular target for different ARVs in HIV treatments. We found that antiretroviral drugs (ARVs) consistently inhibit arginase (ARG)-I activity both in intact and lysed cells. In docking studies, darunavir (DRV) and atazanavir (ATV) showed similar scores compared to both l-arginine and the ARG antagonist, Nω-hydroxy-nor-arginine (nor-NOHA). Efavirenz (EFV) and nevirapine (NVP), which are less potent in inhibiting ARG in the biochemical assay, also had lower scores. In conclusion, the present findings in a human model support the notion that ARG pathway can be envisioned as an additional and new molecular target of different ARVs in HIV treatments.

  5. VISUALIZATION-BASED ANALYSIS FOR A MIXED-INHIBITION BINARY PBPK MODEL: DETERMINATION OF INHIBITION MECHANISM

    EPA Science Inventory

    A physiologically-based pharmacokinetic (PBPK) model incorporating mixed enzyme inhibition was used to determine mechanism of the metabolic interactions occurring during simultaneous inhalation exposures to the organic solvents chloroform and trichloroethylene (TCE).

    V...

  6. Purinergic inhibition of glucose transport in cardiomyocytes.

    PubMed

    Fischer, Y; Becker, C; Löken, C

    1999-01-08

    ATP is known to act as an extracellular signal in many organs. In the heart, extracellular ATP modulates ionic processes and contractile function. This study describes a novel, metabolic effect of exogenous ATP in isolated rat cardiomyocytes. In these quiescent (i.e. noncontracting) cells, micromolar concentrations of ATP depressed the rate of basal, catecholamine-stimulated, or insulin-stimulated glucose transport by up to 60% (IC50 for inhibition of insulin-dependent glucose transport, 4 microM). ATP decreased the amount of glucose transporters (GLUT1 and GLUT4) in the plasma membrane, with a concomitant increase in intracellular microsomal membranes. A similar glucose transport inhibition was produced by P2 purinergic agonists with the following rank of potencies: ATP approximately ATPgammaS approximately 2-methylthio-ATP (P2Y-selective) > ADP > alpha,betameATP (P2X-selective), whereas the P1 purinoceptor agonist adenosine was ineffective. The effect of ATP was suppressed by the poorly subtype-selective P2 antagonist pyridoxal-phosphate-6-azophenyl-2', 4'-disulfonic acid but, surprisingly, not by the nonselective antagonist suramin nor by the P2Y-specific Reactive Blue 2. Glucose transport inhibition by ATP was not affected by a drastic reduction of the extracellular concentrations of calcium (down to 10(-9) M) or sodium (down to 0 mM), and it was not mimicked by a potassium-induced depolarization, indicating that purinoceptors of the P2X family (which are nonselective cation channels whose activation leads to a depolarizing sodium and calcium influx) are not involved. Inhibition was specific for the transmembrane transport of glucose because ATP did not inhibit (i) the rate of glycolysis under conditions where the transport step is no longer rate-limiting nor (ii) the rate of [1-14C]pyruvate decarboxylation. In conclusion, extracellular ATP markedly inhibits glucose transport in rat cardiomyocytes by promoting a redistribution of glucose transporters from the

  7. Spatially Reciprocal Inhibition of Inhibition within a Stimulus Selection Network in the Avian Midbrain

    PubMed Central

    Goddard, C. Alex; Mysore, Shreesh P.; Bryant, Astra S.; Huguenard, John R.; Knudsen, Eric I.

    2014-01-01

    Reciprocal inhibition between inhibitory projection neurons has been proposed as the most efficient circuit motif to achieve the flexible selection of one stimulus among competing alternatives. However, whether such a motif exists in networks that mediate selection is unclear. Here, we study the connectivity within the nucleus isthmi pars magnocellularis (Imc), a GABAergic nucleus that mediates competitive selection in the midbrain stimulus selection network. Using laser photostimulation of caged glutamate, we find that feedback inhibitory connectivity is global within the Imc. Unlike typical lateral inhibition in other circuits, intra-Imc inhibition remains functionally powerful over long distances. Anatomically, we observed long-range axonal projections and retrograde somatic labeling from focal injections of bi-directional tracers in the Imc, consistent with spatial reciprocity of intra-Imc inhibition. Together, the data indicate that spatially reciprocal inhibition of inhibition occurs throughout the Imc. Thus, the midbrain selection circuit possesses the most efficient circuit motif possible for fast, reliable, and flexible selection. PMID:24465755

  8. Lithium inhibits tumor lymphangiogenesis and metastasis through the inhibition of TGFBIp expression in cancer cells.

    PubMed

    Maeng, Yong-Sun; Lee, Rina; Lee, Boram; Choi, Seung-Il; Kim, Eung Kweon

    2016-02-09

    Metastasis is the main cause of mortality in cancer patients. Although there are many anti-cancer drugs targeting tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression; in particular, lymphangiogenesis is pivotal for metastasis in cancer. Here we report that lithium inhibits colon cancer metastasis by blocking lymphangiogenesis. Lithium reduces the expression of transforming growth factor-β-induced protein (TGFBIp) in colon cancer cells by inhibiting Smad3 phosphorylation via GSK3β inactivation. Moreover, lithium inhibits lymphatic endothelial cell migration, which is increased upon TGFBIp expression in tumor cells. Lithium had no significant effect on SW620 tumor growth in vitro and in vivo; however, it inhibited lymphangiogenesis in tumors. In tumor xenografts model, lithium was found to prevent metastasis to the lungs, liver, and lymph nodes by inhibiting TGFBIp-induced tumor lymphangiogenesis. Collectively, our findings demonstrate a novel role of lithium in the inhibition of colon cancer metastasis by blocking TGFBIp expression, and thereby TGFBIp-induced lymphangiogenesis, in primary tumors.

  9. Wogonin inhibits osteoclast differentiation by inhibiting NFATc1 translocation into the nucleus

    PubMed Central

    GENG, XIAOLIN; YANG, LIBIN; ZHANG, CHAO; QIN, HUA; LIANG, QIUDONG

    2015-01-01

    The aim of the present study was to identify a natural product with the ability to inhibit nuclear factor of activated T cells c1 (NFATc1) translocation from the cytoplasm to the nucleus by high-throughput screening, and to investigate the effect of the natural product upon osteoclast differentiation and its underlying mechanism. An NFATc1 antagonist redistribution assay was performed in U2OS-NFATc1 cells against a natural product library, and Wogonin was found to have the ability to inhibit the NFATc1 translocation from the cytoplasm to the nucleus. The effect of Wogonin on NFATc1 transcription activation was further determined by luciferase assay. An osteoclast differentiation assay was executed to evaluate the effect of Wogonin on osteoclast differentiation. The effect of Wogonin upon the vital genes in osteoclast differentiation was investigated using fluorescent quantitative polymerase chain reaction analysis. The natural product Wogonin significantly inhibited the translocation of NFATc1 from the cytoplasm to the nucleus and its transcriptional activation activity. Wogonin also significantly inhibited osteoclast differentiation and decreased the transcription of osteoclast-associated immunoglobulin-like receptor, tartrate-resistant acid phosphatase and calcitonin receptor. In conclusion, the natural product Wogonin inhibited osteoclast differentiation through the inhibition of NFATc1 translocation from the cytoplasm to the nucleus, and thus the downregulation of genes associated with osteoclast differentiation, which marked Wogonin as a potential treatment for osteoporosis. PMID:26622440

  10. Amiloride inhibits the initiation of Coxsackievirus and poliovirus RNA replication by inhibiting VPg uridylylation.

    PubMed

    Ogram, Sushma A; Boone, Christopher D; McKenna, Robert; Flanegan, James B

    2014-09-01

    The mechanism of amiloride inhibition of Coxsackievirus B3 (CVB3) and poliovirus type 1 (PV1) RNA replication was investigated using membrane-associated RNA replication complexes. Amiloride was shown to inhibit viral RNA replication and VPgpUpU synthesis. However, the drug had no effect on polymerase elongation activity during either (-) strand or (+) strand synthesis. These findings indicated that amiloride inhibited the initiation of RNA synthesis by inhibiting VPg uridylylation. In addition, in silico binding studies showed that amiloride docks in the VPg binding site on the back of the viral RNA polymerase, 3D(pol). Since VPg binding at this site on PV1 3D(pol) was previously shown to be required for VPg uridylylation, our results suggest that amiloride inhibits VPg binding to 3D(pol). In summary, our findings are consistent with a model in which amiloride inhibits VPgpUpU synthesis and viral RNA replication by competing with VPg for binding to 3D(pol).

  11. AMPA receptor inhibition by synaptically released zinc

    PubMed Central

    Kalappa, Bopanna I.; Anderson, Charles T.; Lippard, Stephen J.; Tzounopoulos, Thanos

    2015-01-01

    The vast amount of fast excitatory neurotransmission in the mammalian central nervous system is mediated by AMPA-subtype glutamate receptors (AMPARs). As a result, AMPAR-mediated synaptic transmission is implicated in nearly all aspects of brain development, function, and plasticity. Despite the central role of AMPARs in neurobiology, the fine-tuning of synaptic AMPA responses by endogenous modulators remains poorly understood. Here we provide evidence that endogenous zinc, released by single presynaptic action potentials, inhibits synaptic AMPA currents in the dorsal cochlear nucleus (DCN) and hippocampus. Exposure to loud sound reduces presynaptic zinc levels in the DCN and abolishes zinc inhibition, implicating zinc in experience-dependent AMPAR synaptic plasticity. Our results establish zinc as an activity-dependent, endogenous modulator of AMPARs that tunes fast excitatory neurotransmission and plasticity in glutamatergic synapses. PMID:26647187

  12. Antibiotic inhibition of group I ribozyme function.

    PubMed

    von Ahsen, U; Davies, J; Schroeder, R

    1991-09-26

    The discovery of catalytically active RNA has provided the basis for the evolutionary concept of an RNA world. It has been proposed that during evolution the functions of ancient catalytic RNA were modulated by low molecular weight effectors, related to antibiotics, present in the primordial soup. Antibiotics and RNA may have coevolved in the formation of the modern ribosome. Here we report that a set of aminoglycoside antibiotics, which are known to interact with the decoding region of the 16S ribosomal RNA of Escherichia coli, inhibit the second step of splicing of the T4 phage-derived td intron. Thus catalytic RNA seems to interact not only with a mononucleotide and an amino acid, but also with another class of biomolecules, the sugars. Splicing of other group I introns but not group II introns was inhibited. The similarity in affinity and specificity of these antibiotics for group I introns and rRNAs may result from recognition of evolutionarily conserved structures.

  13. Inhibition of the hammerhead ribozyme by neomycin.

    PubMed Central

    Stage, T K; Hertel, K J; Uhlenbeck, O C

    1995-01-01

    A series of antibiotics was tested for stimulation or inhibition of the hammerhead ribozyme cleavage reaction. Neomycin was found to be a potent inhibitor of the reaction with a Kl of 13.5 microM. Two hammerheads with well-characterized kinetics were used to determine which steps in the reaction mechanism were inhibited by neomycin. The data suggest that neomycin interacts preferentially with the enzyme-substrate complex and that this interaction leads to a reduction in the cleavage rate by stabilizing the ground state of the complex and destabilizing the transition state of the cleavage step. A comparison of neomycin with other aminoglycosides and inhibitors of hammerhead cleavage implies that the ammonium ions of neomycin are important for the antibiotic-hammerhead interaction. PMID:7489494

  14. Allosteric Inhibition of the Neuropeptidase Neurolysin*

    PubMed Central

    Hines, Christina S.; Ray, Kallol; Schmidt, Jack J.; Xiong, Fei; Feenstra, Rolf W.; Pras-Raves, Mia; de Moes, Jan Peter; Lange, Jos H. M.; Melikishvili, Manana; Fried, Michael G.; Mortenson, Paul; Charlton, Michael; Patel, Yogendra; Courtney, Stephen M.; Kruse, Chris G.; Rodgers, David W.

    2014-01-01

    Neuropeptidases specialize in the hydrolysis of the small bioactive peptides that play a variety of signaling roles in the nervous and endocrine systems. One neuropeptidase, neurolysin, helps control the levels of the dopaminergic circuit modulator neurotensin and is a member of a fold group that includes the antihypertensive target angiotensin converting enzyme. We report the discovery of a potent inhibitor that, unexpectedly, binds away from the enzyme catalytic site. The location of the bound inhibitor suggests it disrupts activity by preventing a hinge-like motion associated with substrate binding and catalysis. In support of this model, the inhibition kinetics are mixed, with both noncompetitive and competitive components, and fluorescence polarization shows directly that the inhibitor reverses a substrate-associated conformational change. This new type of inhibition may have widespread utility in targeting neuropeptidases. PMID:25378390

  15. Allosteric inhibition of the neuropeptidase neurolysin.

    PubMed

    Hines, Christina S; Ray, Kallol; Schmidt, Jack J; Xiong, Fei; Feenstra, Rolf W; Pras-Raves, Mia; de Moes, Jan Peter; Lange, Jos H M; Melikishvili, Manana; Fried, Michael G; Mortenson, Paul; Charlton, Michael; Patel, Yogendra; Courtney, Stephen M; Kruse, Chris G; Rodgers, David W

    2014-12-19

    Neuropeptidases specialize in the hydrolysis of the small bioactive peptides that play a variety of signaling roles in the nervous and endocrine systems. One neuropeptidase, neurolysin, helps control the levels of the dopaminergic circuit modulator neurotensin and is a member of a fold group that includes the antihypertensive target angiotensin converting enzyme. We report the discovery of a potent inhibitor that, unexpectedly, binds away from the enzyme catalytic site. The location of the bound inhibitor suggests it disrupts activity by preventing a hinge-like motion associated with substrate binding and catalysis. In support of this model, the inhibition kinetics are mixed, with both noncompetitive and competitive components, and fluorescence polarization shows directly that the inhibitor reverses a substrate-associated conformational change. This new type of inhibition may have widespread utility in targeting neuropeptidases.

  16. Non-Classical Inhibition of Carbonic Anhydrase

    PubMed Central

    Lomelino, Carrie L.; Supuran, Claudiu T.; McKenna, Robert

    2016-01-01

    Specific isoforms from the carbonic anhydrase (CA) family of zinc metalloenzymes have been associated with a variety of diseases. Isoform-specific carbonic anhydrase inhibitors (CAIs) are therefore a major focus of attention for specific disease treatments. Classical CAIs, primarily sulfonamide-based compounds and their bioisosteres, are examined as antiglaucoma, antiepileptic, antiobesity, antineuropathic pain and anticancer compounds. However, many sulfonamide compounds inhibit all CA isoforms nonspecifically, diluting drug effectiveness and causing undesired side effects due to off-target inhibition. In addition, a small but significant percentage of the general population cannot be treated with sulfonamide-based compounds due to a sulfa allergy. Therefore, CAIs must be developed that are not only isoform specific, but also non-classical, i.e. not based on sulfonamides, sulfamates, or sulfamides. This review covers the classes of non-classical CAIs and the recent advances in the development of isoform-specific inhibitors based on phenols, polyamines, coumarins and their derivatives. PMID:27438828

  17. Inhibition Controls Asynchronous States of Neuronal Networks

    PubMed Central

    Treviño, Mario

    2016-01-01

    Computations in cortical circuits require action potentials from excitatory and inhibitory neurons. In this mini-review, I first provide a quick overview of findings that indicate that GABAergic neurons play a fundamental role in coordinating spikes and generating synchronized network activity. Next, I argue that these observations helped popularize the notion that network oscillations require a high degree of spike correlations among interneurons which, in turn, produce synchronous inhibition of the local microcircuit. The aim of this text is to discuss some recent experimental and computational findings that support a complementary view: one in which interneurons participate actively in producing asynchronous states in cortical networks. This requires a proper mixture of shared excitation and inhibition leading to asynchronous activity between neighboring cells. Such contribution from interneurons would be extremely important because it would tend to reduce the spike correlation between neighboring pyramidal cells, a drop in redundancy that could enhance the information-processing capacity of neural networks. PMID:27274721

  18. Dimethyl sulfoxide inhibits bioactivation of sulindac.

    PubMed

    Swanson, B N; Boppana, V K; Vlasses, P H; Rotmensch, H H; Ferguson, R K

    1983-07-01

    Sulindac, a nonsteroidal anti-inflammatory agent, is converted to a bioactive sulfide metabolite via reversible reduction of its sulfoxide moiety. To test whether DMSO can inhibit conversion of sulindac to its active form, eight healthy men received, in a randomized, crossover manner, 400 mg of sulindac, orally, either alone or 60 min after an oral dose of DMSO (30 ml, 70% solution). After the drug combination, mean plasma concentrations of the sulfide metabolite were significantly lower than in controls at 1.5, 2, 3, 4, and 8 hr after sulindac administration. The mean area under the plasma sulfide concentration-time curve for 0 to 12 hr was 30% (range 7% to 56%) lower after DMSO treatment. This study suggests that DMSO can inhibit metabolism of other sulfoxides in man and may antagonize the therapeutic efficacy of sulindac.

  19. Kinetics of ethanol inhibition in alcohol fermentation.

    PubMed

    Luong, J H

    1985-03-01

    The inhibitory effect of ethanol on yeast growth and fermentation has been studied for the strain Saccharomyces cerevisiae ATCC No. 4126 under anaerobic batch conditions. The results obtained reveal that there is no striking difference between the response of growth and ethanol fermentation. Two kinetic models are also proposed to describe the kinetic pattern of ethanol inhibition on the specific rates of growth and ethanol fermentation: microi/micro0 = 1 - (P/Pm)alpha (for growth) nui/nu0 = 1 - (P/P'm)beta (for ethanol production). The maximum allowable ethanol concentration above which cells do not grow was predicted to be 112 g/L. The ethanol-producing capability of the cells was completely inhibited at 115 g/L ethanol. The proposed models appear to accurately represent the experimental data obtained in this study and the literature data.

  20. Kinetics of ethanol inhibition in alcohol fermentation

    SciTech Connect

    Luong, J.H.T.

    1985-01-01

    The inhibitory effect of ethanol on yeast growth and fermentation has been studied for the strain Saccharo-myces cerevisiae ATCC No. 4126 under anaerobic batch conditions. The results obtained reveal that there is no striking difference between the response of growth and ethanol fermentation. Two kinetic models are also proposed to describe the kinetic pattern of ethanol inhibition on the specific rates of growth and ethanol fermentation. The maximum allowable ethanol concentration above which cells do not grow was predicted to be 112 g/L. The ethanol-producing capability of the cells was completely inhibited at 115 g/L ethanol. The proposed models appear to accurately represent the experimental data obtained in this study and the literature data.

  1. Blocking of potentiation of latent inhibition.

    PubMed

    Hall, Geoffrey; Rodriguez, Gabriel

    2011-01-01

    We present a theory of latent inhibition based on the Pearce-Hall (Pearce & Hall, 1980) model for classical conditioning. Its central features are (1) that the associability of a stimulus declines as it comes to predict its consequences and (2) that nonreinforced exposure to a stimulus engages an associative learning process that makes the stimulus an accurate predictor of its consequences (in this case, the occurrence of no event). A formalization of this theory is shown to accommodate the finding that preexposure in compound with another cue can potentiate latent inhibition to the target cue. It further predicts that preexposure to the added cue will eliminate the potentiation effect. An experiment using rats and the flavor-aversion procedure confirmed this prediction.

  2. AMPK inhibition in health and disease.

    PubMed

    Viollet, Benoit; Horman, Sandrine; Leclerc, Jocelyne; Lantier, Louise; Foretz, Marc; Billaud, Marc; Giri, Shailendra; Andreelli, Fabrizio

    2010-08-01

    All living organisms depend on dynamic mechanisms that repeatedly reassess the status of amassed energy, in order to adapt energy supply to demand. The AMP-activated protein kinase (AMPK) alphabetagamma heterotrimer has emerged as an important integrator of signals managing energy balance. Control of AMPK activity involves allosteric AMP and ATP regulation, auto-inhibitory features and phosphorylation of its catalytic (alpha) and regulatory (beta and gamma) subunits. AMPK has a prominent role not only as a peripheral sensor but also in the central nervous system as a multifunctional metabolic regulator. AMPK represents an ideal second messenger for reporting cellular energy state. For this reason, activated AMPK acts as a protective response to energy stress in numerous systems. However, AMPK inhibition also actively participates in the control of whole body energy homeostasis. In this review, we discuss recent findings that support the role and function of AMPK inhibition under physiological and pathological states.

  3. Methamphetamine inhibits antigen processing, presentation, and phagocytosis.

    PubMed

    Tallóczy, Zsolt; Martinez, Jose; Joset, Danielle; Ray, Yonaton; Gácser, Attila; Toussi, Sima; Mizushima, Noboru; Nosanchuk, Joshua D; Nosanchuk, Josh; Goldstein, Harris; Loike, John; Sulzer, David; Santambrogio, Laura

    2008-02-08

    Methamphetamine (Meth) is abused by over 35 million people worldwide. Chronic Meth abuse may be particularly devastating in individuals who engage in unprotected sex with multiple partners because it is associated with a 2-fold higher risk for obtaining HIV and associated secondary infections. We report the first specific evidence that Meth at pharmacological concentrations exerts a direct immunosuppressive effect on dendritic cells and macrophages. As a weak base, Meth collapses the pH gradient across acidic organelles, including lysosomes and associated autophagic organelles. This in turn inhibits receptor-mediated phagocytosis of antibody-coated particles, MHC class II antigen processing by the endosomal-lysosomal pathway, and antigen presentation to splenic T cells by dendritic cells. More importantly Meth facilitates intracellular replication and inhibits intracellular killing of Candida albicans and Cryptococcus neoformans, two major AIDS-related pathogens. Meth exerts previously unreported direct immunosuppressive effects that contribute to increased risk of infection and exacerbate AIDS pathology.

  4. Inhibition of Plasmodium Liver Infection by Ivermectin

    PubMed Central

    Mendes, António M.; Albuquerque, Inês S.; Machado, Marta; Pissarra, Joana; Meireles, Patrícia

    2016-01-01

    ABSTRACT Avermectins are powerful endectocides with an established potential to reduce the incidence of vector-borne diseases. Here, we show that several avermectins inhibit the hepatic stage of Plasmodium infection in vitro. Notably, ivermectin potently inhibits liver infection in vivo by impairing parasite development inside hepatocytes. This impairment has a clear impact on the ensuing blood stage parasitemia, reducing disease severity and enhancing host survival. Ivermectin has been proposed as a tool to control malaria transmission because of its effects on the mosquito vector. Our study extends the effect of ivermectin to the early stages of mammalian host infection and supports the inclusion of this multipurpose drug in malaria control strategies. PMID:27895022

  5. The inhibition of tyrosinase by pyridinones.

    PubMed Central

    Hider, R C; Lerch, K

    1989-01-01

    3-Hydroxypyridine-4-ones have potential as orally active chelators of iron(III) and therefore may find application in the treatment of thalassaemia. An undesirable feature of these molecules is that they inhibit tyrosinase. We have established that alkyl substitution at position 2 in the aromatic ring minimizes interaction with tyrosinase and does so without appreciably influencing the affinity for iron(III). PMID:2493243

  6. Henri Laborit and the inhibition of action.

    PubMed

    Kunz, Edward

    2014-03-01

    Henri Laborit was one of the founders of modern neuropsychopharmacology, having discovered, or participated in, the discovery of chlorpromazine, gamma-OH, clomethiazole, and minaprine. He also put forward a theory regarding the necessity of counteracting the negative consequences of defense mechanisms during anesthesia or behavioral inhibition. The scope of his work covers neurophysiology, pharmacology, psychiatry, and psychosomatics. His independence of spirit meant that most of his research was not done within university settings.

  7. Henri Laborit and the inhibition of action

    PubMed Central

    Kunz, Edward

    2014-01-01

    Henri Laborit was one of the founders of modern neuropsychopharmacology, having discovered, or participated in, the discovery of chlorpromazine, gamma-OH, clomethiazole, and minaprine. He also put forward a theory regarding the necessity of counteracting the negative consequences of defense mechanisms during anesthesia or behavioral inhibition. The scope of his work covers neurophysiology, pharmacology, psychiatry, and psychosomatics. His independence of spirit meant that most of his research was not done within university settings. PMID:24733976

  8. Obestatin acts in brain to inhibit thirst.

    PubMed

    Samson, Willis K; White, Meghan M; Price, Christopher; Ferguson, Alastair V

    2007-01-01

    Derived from the same prohormone, obestatin has been reported to exert effects on food intake that oppose those of ghrelin. The obestatin receptor GPR39 is present in brain and pituitary gland. Since the gene encoding those two peptides is expressed also in those tissues, we examined further the possible actions of obestatin in vivo and in vitro. Intracerebroventricular administration of obestatin inhibited water drinking in ad libitum-fed and -watered rats, and in food-and water-deprived animals. The effects on water drinking preceded and were more pronounced than any effect on food intake, and did not appear to be the result of altered locomotor/behavioral activity. In addition, obestatin inhibited ANG II-induced water drinking in animals provided free access to water and food. Current-clamp recordings from cultured, subfornical organ neurons revealed significant effects of the peptide on membrane potential, suggesting this as a potential site of action. In pituitary cell cultures, log molar concentrations of obestatin ranging from 1.0 pM to 100 nM failed to alter basal growth hormone (GH) secretion. In addition, 100 nM obestatin failed to interfere with the stimulation of GH secretion by GH-releasing hormone or ghrelin and did not alter the inhibition by somatostatin in vitro. We conclude that obestatin does not act in pituitary gland to regulate GH secretion but may act in brain to alter thirst mechanisms. Importantly, in rats the effects of obestatin on food intake may be secondary to an action of the peptide to inhibit water drinking.

  9. Inhibition of Alkaline Phosphatase by Several Diuretics

    DTIC Science & Technology

    1980-01-01

    August 20th, 1979) . . Summary , . Acetazolamide, furosemide, ethacrynic acid and chlorothiazide, diuretics of considerable structural diversity, inhibit...Ki is calculated to be 8.4, 7.0, 2.8 and 0.1 mmol/l for acetazolamide, furosemide, ethacrynic acid and chlorothiazide, respectively. Chlorothiazide...is a much more potent inhibitor of alkaline phos- phatase than the other three diuretics. The combination of ethacrynic acid and cysteine, itself an

  10. Inhibiting the Function of an Enzyme

    SciTech Connect

    2015-06-17

    In order to stop bacteria from reproducing and causing a disease like tuberculosis, researchers must first block its enzymes' ability to bind with certain molecules. A research team from Brandeis University worked with the Advanced Protein Characterization Facility at Argonne National Laboratory to define 13 different bacterial structures and uncover the mechanism by which their enzymes form and break bonds with molecules. This animation depicts how an enzyme may be inhibited using this knowledge.

  11. An Activation Threshold Model for Response Inhibition

    PubMed Central

    MacDonald, Hayley J.; McMorland, Angus J. C.; Stinear, Cathy M.; Coxon, James P.; Byblow, Winston D.

    2017-01-01

    Reactive response inhibition (RI) is the cancellation of a prepared response when it is no longer appropriate. Selectivity of RI can be examined by cueing the cancellation of one component of a prepared multi-component response. This substantially delays execution of other components. There is debate regarding whether this response delay is due to a selective neural mechanism. Here we propose a computational activation threshold model (ATM) and test it against a classical “horse-race” model using behavioural and neurophysiological data from partial RI experiments. The models comprise both facilitatory and inhibitory processes that compete upstream of motor output regions. Summary statistics (means and standard deviations) of predicted muscular and neurophysiological data were fit in both models to equivalent experimental measures by minimizing a Pearson Chi-square statistic. The ATM best captured behavioural and neurophysiological dynamics of partial RI. The ATM demonstrated that the observed modulation of corticomotor excitability during partial RI can be explained by nonselective inhibition of the prepared response. The inhibition raised the activation threshold to a level that could not be reached by the original response. This was necessarily followed by an additional phase of facilitation representing a secondary activation process in order to reach the new inhibition threshold and initiate the executed component of the response. The ATM offers a mechanistic description of the neural events underlying RI, in which partial movement cancellation results from a nonselective inhibitory event followed by subsequent initiation of a new response. The ATM provides a framework for considering and exploring the neuroanatomical constraints that underlie RI. PMID:28085907

  12. Inhibition of aromatase activity by flavonoids.

    PubMed

    Jeong, H J; Shin, Y G; Kim, I H; Pezzuto, J M

    1999-06-01

    In searching for potent cancer chemopreventive agents from synthetic or natural products, 28 randomly selected flavonoids were screened for inhibitory effects against partially purified aromatase prepared from human placenta. Over 50% of the flavonoids significantly inhibited aromatase activity, with greatest activity being demonstrated with apigenin (IC50: 0.9 microg/mL), chrysin (IC50: 1.1 microg/mL), and hesperetin (IC50: 1.0 microg/mL).

  13. Alpha-1-antitrypsin inhibits nitric oxide production.

    PubMed

    Chan, Edward D; Pott, Gregory B; Silkoff, Philip E; Ralston, Annemarie H; Bryan, Courtney L; Shapiro, Leland

    2012-12-01

    NO is an endogenously produced gas that regulates inflammation, vascular tone, neurotransmission, and immunity. NO production can be increased by exposing cells to several endogenous and exogenous proinflammatory mediators, including IFN-γ, TNF-α, IL-1β, and LPS. As AAT has been shown to inhibit cell activation and suppress cytokine production associated with proinflammatory stimulation, we examined AAT for NO-suppressive function. In RAW 264.7 murine macrophagic cells, physiological AAT concentrations significantly inhibited combined LPS- and IFN-γ-induced NO synthesis, and NO synthesis inhibition was associated with decreased expression of iNOS, suppressed NF-κB activation, and reduced translocation of extracellular AAT into the interior of RAW 264.7 cells. CE-2072, a synthetic inhibitor of serine proteases, also suppressed NO production, iNOS expression, and NF-κB activation. However, AAT did not alter activation of intracellular MAPKs. In subjects with genetic AAT deficiency, exhaled NO was increased significantly compared with exhaled NO in healthy controls. These in vitro and in vivo studies suggest that AAT is an endogenous inhibitor of NO production. Administering AAT or AAT-like molecules may have use as a treatment for diseases associated with excessive NO production.

  14. ROCK inhibition prevents early mouse embryo development.

    PubMed

    Duan, Xing; Chen, Kun-Lin; Zhang, Yu; Cui, Xiang-Shun; Kim, Nam-Hyung; Sun, Shao-Chen

    2014-08-01

    ROCK is a Rho-GTPase effector that is important for actin assembly and is involved in various cellular functions, including cell contraction, migration, motility, and tumor cell invasion. In this study, we investigated ROCK expression and function during early mouse embryo development. Inhibiting ROCK by Y-27632 treatment at the zygote stage resulted in first cleavage failure, and most embryos failed to develop to the 8-cell stage. When adding Y-27632 at the 8-cell stage, embryos failed to undergo compaction and could not develop into blastocysts. In addition, fluorescence staining intensity analysis indicated that actin expression at blastomere membranes was significantly reduced. After ROCK inhibition, two or more nuclei were observed in a cell, which indicated possible cytokinesis failure. Moreover, after ROCK inhibition with Y-27632, the phosphorylation levels of LIMK1/2, a downstream molecule of ROCK, were decreased at blastomere membranes. Thus, our results showed conserved roles for ROCK in this mammalian embryo model and indicated that a ROCK-LIMK1/2-actin pathway might regulate cleavage and blastocyst formation during early mouse embryo development.

  15. Motor cortex inhibition induced by acoustic stimulation.

    PubMed

    Kühn, Andrea A; Sharott, Andrew; Trottenberg, Thomas; Kupsch, Andreas; Brown, Peter

    2004-09-01

    The influence of the brainstem motor system on cerebral motor areas may play an important role in motor control in health and disease. A new approach to investigate this interaction in man is combining acoustic stimulation activating the startle system with transcranial magnetic stimulation (TMS) over the motor cortex. However, it is unclear whether the inhibition of TMS responses following acoustic stimulation occurs at the level of the motor cortex through reticulo-cortical projections or subcortically, perhaps through reticulo-spinal projections. We compared the influence of acoustic stimulation on motor effects elicited by TMS over motor cortical areas to those evoked with subcortical electrical stimulation (SES) through depth electrodes in five patients treated with deep brain stimulation for Parkinson's disease. SES bypasses the motor cortex, demonstrating any interaction with acoustic stimuli at the subcortical level. EMG was recorded from the contralateral biceps brachii muscle. Acoustic stimulation was delivered binaurally through headphones and used as a conditioning stimulus at an interstimulus interval of 50 ms. When TMS was used as the test stimulus, the area and amplitude of the conditioned motor response was significantly inhibited (area: 57.5+/-12.9%, amplitude: 47.9+/-7.4%, as percentage of unconditioned response) whereas facilitation occurred with SES (area: 110.1+/-4.3%, amplitude: 116.9+/-6.9%). We conclude that a startle-evoked activation of reticulo-cortical projections transiently inhibits the motor cortex.

  16. Pharmacological Inhibition of Feline Immunodeficiency Virus (FIV)

    PubMed Central

    Mohammadi, Hakimeh; Bienzle, Dorothee

    2012-01-01

    Feline immunodeficiency virus (FIV) is a member of the retroviridae family of viruses and causes an acquired immunodeficiency syndrome (AIDS) in domestic and non-domestic cats worldwide. Genome organization of FIV and clinical characteristics of the disease caused by the virus are similar to those of human immunodeficiency virus (HIV). Both viruses infect T lymphocytes, monocytes and macrophages, and their replication cycle in infected cells is analogous. Due to marked similarity in genomic organization, virus structure, virus replication and disease pathogenesis of FIV and HIV, infection of cats with FIV is a useful tool to study and develop novel drugs and vaccines for HIV. Anti-retroviral drugs studied extensively in HIV infection have targeted different steps of the virus replication cycle: (1) inhibition of virus entry into susceptible cells at the level of attachment to host cell surface receptors and co-receptors; (2) inhibition of fusion of the virus membrane with the cell membrane; (3) blockade of reverse transcription of viral genomic RNA; (4) interruption of nuclear translocation and viral DNA integration into host genomes; (5) prevention of viral transcript processing and nuclear export; and (6) inhibition of virion assembly and maturation. Despite much success of anti-retroviral therapy slowing disease progression in people, similar therapy has not been thoroughly investigated in cats. In this article we review current pharmacological approaches and novel targets for anti-lentiviral therapy, and critically assess potentially suitable applications against FIV infection in cats. PMID:22754645

  17. Inhibition of fibroblast proliferation by Actinobacillus actinomycetemcomitans.

    PubMed Central

    Shenker, B J; Kushner, M E; Tsai, C C

    1982-01-01

    We have examined soluble sonic extracts of Actinobacillus actinomycetemcomitans for their ability to alter human and murine fibroblast proliferation. We found that extracts of all A. actinomycetemcomitans strains examined (both leukotoxic and nonleukotoxic) caused a dose-dependent inhibition of both murine and human fibroblast proliferation as assessed by DNA synthesis ([3H]thymidine incorporation). Addition of sonic extract simultaneously with [3H]thymidine had no effect on incorporation, indicating that suppression was not due to the presence of excessive amounts of cold thymidine. Inhibition of DNA synthesis was also paralleled by decreased RNA synthesis ([3H]uridine incorporation) and by a decrease in cell growth as assessed by direct cell counts; there was no effect on cell viability. The suppressive factor(s) is heat labile; preliminary purification and characterization studies indicate that it is a distinct and separate moiety from other A. actinomycetemcomitans mediators previously reported, including leukotoxin, immune suppressive factor, and endotoxin. Although it is not clear how A. actinomycetemcomitans acts to cause disease, we propose that one aspect of the pathogenicity of this organism rests in its ability to inhibit fibroblast growth, which in turn could contribute to the collagen loss associated with certain forms of periodontal disease, in particular juvenile periodontitis. PMID:7152684

  18. Gabapentin inhibits central sensitization during migraine.

    PubMed

    Zhang, Yanbo; Shao, Guo; Zhang, Wei; Li, Sijie; Niu, Jingzhong; Hu, Dongmei; Yang, Mingfeng; Ji, Xunming

    2013-11-15

    Peripheral and central sensitizations are phenomena that occur during migraine. The role of pentin, a migraine preventive drug, on central sensitization remains unclear. In this study, a rat model of migraine was established by electrical stimulation of the trigeminal ganglion, and the an-imals were given intragastric gabapentin. Changes in amino acid content in the cerebrospinal fluid and protein kinase C membrane translocation in the spinal trigeminal nucleus were examined to clarify the mechanisms underlying the efficacy of gabapentin in the treatment of central sensitization during migraine. Electrophysiology, liquid chromatography-mass spectrometry and western blot analysis results revealed that gabapentin reduces neuronal excitability in the spinal nucleus in the trigeminal nerve, decreases excitatory amino acid content and inhibits the activation of protein ki-nase C. This provides evidence that excitatory amino acids and protein kinase C are involved in the formation and maintenance of central sensitization during migraine. Gabapentin inhibits migraine by reducing excitatory amino acid content in the cerebrospinal fluid and inhibiting protein kinase C ac-tivation.

  19. Menaquinone Analogs Inhibit Growth of Bacterial Pathogens

    PubMed Central

    Merriman, Joseph A.; Salgado-Pabón, Wilmara; Mueller, Elizabeth A.; Spaulding, Adam R.; Vu, Bao G.; Chuang-Smith, Olivia N.; Kohler, Petra L.; Kirby, John R.

    2013-01-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents. PMID:23959313

  20. Menaquinone analogs inhibit growth of bacterial pathogens.

    PubMed

    Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R

    2013-11-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.

  1. JAK INHIBITION AND PROGRESSIVE KIDNEY DISEASE

    PubMed Central

    Brosius, Frank C.; He, John Cijiang

    2015-01-01

    Purpose of review To review the role of JAK-STAT signaling in the progression of chronic kidney diseases. Recent findings The JAK-STAT pathway transmits signals from extracellular ligands, including many cytokines and chemokines. While these responses are best characterized in lymphoid cells, they also occur in kidney cells such as podocytes, mesangial cells, and tubular cells. JAK-STAT expression and signaling abnormalities occur in humans and animal models of different chronic kidney diseases. Enhanced expression and augmented activity of JAK1, JAK2 and STAT3 promote diabetic nephropathy and their inhibition appears to reduce disease. Activation of JAK-STAT signaling in autosomal dominant polycystic kidney disease may play an important role in cyst growth. Activation of JAK-STAT signaling promotes HIV-associated nephropathy and may also participate in the tubular responses to chronic obstructive uropathy. Based on data from experimental models, inhibition of JAK-STAT signaling, via increased expression of the suppressors of cytokine signaling proteins or pharmacologic inhibition of JAK and STAT proteins, could play a therapeutic role in multiple chronic kidney diseases. Summary Activation of the JAK-STAT pathway appears to play a role in the progression of some chronic kidney diseases. More work is needed to determine the specific role the pathway plays in individual diseases. PMID:25415616

  2. Inhibition of SIRT2 suppresses hepatic fibrosis.

    PubMed

    Arteaga, Maribel; Shang, Na; Ding, Xianzhong; Yong, Sherri; Cotler, Scott J; Denning, Mitchell F; Shimamura, Takashi; Breslin, Peter; Lüscher, Bernhard; Qiu, Wei

    2016-06-01

    Liver fibrosis can progress to cirrhosis and result in serious complications of liver disease. The pathogenesis of liver fibrosis involves the activation of hepatic stellate cells (HSCs), the underlying mechanisms of which are not fully known. Emerging evidence suggests that the classic histone deacetylases play a role in liver fibrosis, but the role of another subfamily of histone deacetylases, the sirtuins, in the development of hepatic fibrosis remains unknown. In this study, we found that blocking the activity of sirtuin 2 (SIRT2) by using inhibitors or shRNAs significantly suppressed fibrogenic gene expression in HSCs. We further demonstrated that inhibition of SIRT2 results in the degradation of c-MYC, which is important for HSC activation. In addition, we discovered that inhibition of SIRT2 suppresses the phosphorylation of ERK, which is critical for the stabilization of c-MYC. Moreover, we found that Sirt2 deficiency attenuates the hepatic fibrosis induced by carbon tetrachloride (CCl4) and thioacetamide (TAA). Furthermore, we showed that SIRT2, p-ERK, and c-MYC proteins are all overexpressed in human hepatic fibrotic tissues. These data suggest a critical role for the SIRT2/ERK/c-MYC axis in promoting hepatic fibrogenesis. Inhibition of the SIRT2/ERK/c-MYC axis represents a novel strategy to prevent and to potentially treat liver fibrosis and cirrhosis.

  3. Trace element inhibition of phytase activity.

    PubMed

    Santos, T; Connolly, C; Murphy, R

    2015-02-01

    Nowadays, 70 % of global monogastric feeds contains an exogenous phytase. Phytase supplementation has enabled a more efficient utilisation of phytate phosphorous (P) and reduction of P pollution. Trace minerals, such as iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) are essential for maintaining health and immunity as well as being involved in animal growth, production and reproduction. Exogenous sources of phytase and trace elements are regularly supplemented to monogastric diets and usually combined in a premix. However, the possibility for negative interaction between individual components within the premix is high and is often overlooked. Therefore, this initial study focused on assessing the potential in vitro interaction between inorganic and organic chelated sources of Fe, Zn, Cu and Mn with three commercially available phytase preparations. Additionally, this study has investigated if the degree of enzyme inhibition was dependent of the type of chelated sources. A highly significant relationship between phytase inhibition, trace mineral type as well as mineral source and concentration, p < 0.001 was verified. The proteinate sources of OTMs were consistently and significantly less inhibitory than the majority of the other sources, p < 0.05. This was verified for Escherichia coli and Peniophora lycii phytases for Fe and Zn, as well as for Cu with E. coli and Aspergillus niger phytases. Different chelate trace mineral sources demonstrated diversifying abilities to inhibit exogenous phytase activity.

  4. WR-2721 inhibits parathyroid adenylate cyclase

    SciTech Connect

    Weaver, M.E.; Morrissey, J.; McConkey, C. Jr.; Goldfarb, S.; Slatopolsky, E.; Martin, K.J.

    1987-02-01

    WR-2721 (S-2-(3-aminopropylamino)ethylphosphorothioic acid) is a chemoprotective and radioprotective agent that has been shown to lower serum calcium in dogs and in humans. This is secondary both to impaired release of CaS from bone and diminished secretion of parathyroid hormone (PTH) from parathyroid glands. Because cAMP plays a role in the regulation of PTH secretion and WR-2721 has been shown to lower cAMP levels in radiated mouse spleen, the authors investigated the effects of WR-2721 on cAMP production in dispersed bovine parathyroid cells. Additional, they studied the adenylate cyclase in plasma membranes from normal bovine parathyroid glands after exposure to WR-2721. With parathyroid cells incubated at 0.5 mM CaS , addition of Wr-2721 in concentrations ranging from 0.02 to 2.0 mM resulted in a progressive decrease in intracellular cAMP measured by radioimmunoassay. In plasma membranes of bovine parathyroid cells a dose-dependent decrease in adenylate cyclase activity was noted. Inhibition of the cyclase was seen over a wide range of MgS concentrations. WR-2721 inhibited both basal and NaF, Gpp(NH)(, forskolin, and pertussin toxin-stimulated adenylate cyclase. These data suggest that WR-2721 inhibits the activity of parathyroid adenylate cyclase.

  5. Hydrogen Sulfide Inhibits Plasma Renin Activity

    PubMed Central

    Lu, Ming; Liu, Yi-Hong; Goh, Hong Swen; Wang, Josh Jia Xing; Yong, Qian-Chen; Wang, Rui

    2010-01-01

    The development of renovascular hypertension depends on the release of renin from the juxtaglomerular (JG) cells, a process regulated by intracellular cAMP. Hydrogen sulfide (H2S) downregulates cAMP production in some cell types by inhibiting adenylyl cyclase, suggesting the possibility that it may modulate renin release. Here, we investigated the effect of H2S on plasma renin activity and BP in rat models of renovascular hypertension. In the two-kidney-one-clip (2K1C) model of renovascular hypertension, the H2S donor NaHS prevented and treated hypertension. Compared with vehicle, NaHS significantly attenuated the elevation in plasma renin activity and angiotensin II levels but did not affect plasma angiotensin-converting enzyme activity. Furthermore, NaHS inhibited the upregulation of renin mRNA and protein levels in the clipped kidneys of 2K1C rats. In primary cultures of renin-rich kidney cells, NaHS markedly suppressed forskolin-stimulated renin activity in the medium and the intracellular increase in cAMP. In contrast, NaHS did not affect BP or plasma renin activity in normal or one-kidney-one-clip (1K1C) rats, both of which had normal plasma renin activity. In conclusion, these results demonstrate that H2S may inhibit renin activity by decreasing the synthesis and release of renin, suggesting its potential therapeutic value for renovascular hypertension. PMID:20360313

  6. Wnt signaling inhibits CTL memory programming.

    PubMed

    Xiao, Zhengguo; Sun, Zhifeng; Smyth, Kendra; Li, Lei

    2013-12-01

    Induction of functional CTLs is one of the major goals for vaccine development and cancer therapy. Inflammatory cytokines are critical for memory CTL generation. Wnt signaling is important for CTL priming and memory formation, but its role in cytokine-driven memory CTL programming is unclear. We found that wnt signaling inhibited IL-12-driven CTL activation and memory programming. This impaired memory CTL programming was attributed to up-regulation of eomes and down-regulation of T-bet. Wnt signaling suppressed the mTOR pathway during CTL activation, which was different to its effects on other cell types. Interestingly, the impaired memory CTL programming by wnt was partially rescued by mTOR inhibitor rapamycin. In conclusion, we found that crosstalk between wnt and the IL-12 signaling inhibits T-bet and mTOR pathways and impairs memory programming which can be recovered in part by rapamycin. In addition, direct inhibition of wnt signaling during CTL activation does not affect CTL memory programming. Therefore, wnt signaling may serve as a new tool for CTL manipulation in autoimmune diseases and immune therapy for certain cancers.

  7. Phytic acid inhibits lipid peroxidation in vitro.

    PubMed

    Zajdel, Alicja; Wilczok, Adam; Węglarz, Ludmiła; Dzierżewicz, Zofia

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10-20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products.

  8. Inhibition of granulation tissue growth by histamine.

    PubMed

    Saeki, K; Yokoyama, J; Wake, K

    1975-06-01

    Granulomas were induced in rats by subcutaneous implantation of formalin-soaked filter-paper disks. Daily subcutaneous injection of histamine at doses of two times 0.05 mg/kg and above inhibited the growth of granulation tissue as measured by a marked decrease in the dry-defatted granuloma weight and of the hydroxyproline and hexosamine content. Histological observations of granulation tissue indicated that histamine inhibited the proliferation of fibroblasts and the formation of capillaries. Inhibitory effects were also observed with the histamine releaser, sinomenine, and the histaminase inhibitor, aminoguanidine. These histamine effects seem not to be mediated by glucocorticoid release, since an effective dose level of histamine produced no change in growth or thymus weight. Prednisolone was less potent than histamine in inhibiting Prednisolone was ineffective at the dose tested. Subcutaneous injection of the H2-receptor antagonist, burimamide, blocked these histamine effects and also of sinomeinine and aminoguanidine. The H1-receptor antagonist, mepyramine, did not block these histamine effects. Burimamide alone enhanced the growth of granuloma. These results indicate that granulation-tissue growth in inflammation is affected by the inhibitory effect of endogenous histamine acting through H2-receptors.

  9. Antipneumococcal activity of neuraminidase inhibiting artocarpin.

    PubMed

    Walther, E; Richter, M; Xu, Z; Kramer, C; von Grafenstein, S; Kirchmair, J; Grienke, U; Rollinger, J M; Liedl, K R; Slevogt, H; Sauerbrei, A; Saluz, H P; Pfister, W; Schmidtke, M

    2015-05-01

    Streptococcus (S.) pneumoniae is a major cause of secondary bacterial pneumonia during influenza epidemics. Neuraminidase (NA) is a virulence factor of both pneumococci and influenza viruses. Bacterial neuraminidases (NAs) are structurally related to viral NA and susceptible to oseltamivir, an inhibitor designed to target viral NA. This prompted us to evaluate the antipneumococcal potential of two NA inhibiting natural compounds, the diarylheptanoid katsumadain A and the isoprenylated flavone artocarpin. Chemiluminescence, fluorescence-, and hemagglutination-based enzyme assays were applied to determine the inhibitory efficiency (IC(50) value) of the tested compounds towards pneumococcal NAs. The mechanism of inhibition was studied via enzyme kinetics with recombinant NanA NA. Unlike oseltamivir, which competes with the natural substrate of NA, artocarpin exhibits a mixed-type inhibition with a Ki value of 9.70 μM. Remarkably, artocarpin was the only NA inhibitor (NAI) for which an inhibitory effect on pneumococcal growth (MIC: 0.99-5.75 μM) and biofilm formation (MBIC: 1.15-2.97 μM) was observable. In addition, we discovered that the bactericidal effect of artocarpin can reduce the viability of pneumococci by a factor of >1000, without obvious harm to lung epithelial cells. This renders artocarpin a promising natural product for further investigations.

  10. Phytic Acid Inhibits Lipid Peroxidation In Vitro

    PubMed Central

    Węglarz, Ludmiła; Dzierżewicz, Zofia

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10–20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products. PMID:24260736

  11. Inhibition of acetylcholinesterase by Tea Tree oil.

    PubMed

    Mills, Clive; Cleary, Brian J; Gilmer, John F; Walsh, John J

    2004-03-01

    Pediculosis is a widespread condition reported in schoolchildren. Treatment most commonly involves the physical removal of nits using fine-toothcombs and the chemical treatment of adult lice and eggs with topical preparations. The active constituents of these preparations frequently exert their effects through inhibition of acetylcholinesterase (AChE, EC 3.1.1.7). Increasing resistance to many preparations has led to the search for more effective treatments. Tea Tree oil, otherwise known as Melaleuca oil, has been added to several preparations as an alternative treatment of head lice infestations. In this study two major constituents of Tea Tree oil, 1,8-cineole and terpinen-4-ol, were shown to inhibit acetylcholinesterase at IC50 values (inhibitor concentrations required to give 50% inhibition) of 0.04 and 10.30 mM, respectively. Four samples of Tea Tree oil tested (Tisserand, Body Treats, Main Camp and Irish Health Culture Association Pure Undiluted) showed anticholinesterase activity at IC50 values of 0.05, 0.10, 0.08 and 0.11 microL mL(-1), respectively. The results supported the hypothesis that the insecticidal activity of Tea Tree oil was attributable, in part, to the anticholinesterase activity of Tea Tree oil.

  12. Thiomers: Inhibition of cytochrome P450 activity.

    PubMed

    Iqbal, Javed; Sakloetsakun, Duangkamon; Bernkop-Schnürch, Andreas

    2011-08-01

    The aim of the present study was to investigate the potential of different thiolated polymers (thiomers) on the catalytic activity of CYP450s on one hand and to explore new inhibitors for CYP activity on the other hand. Several thiolated polymers including poly(acrylic acid)-cysteine (PAA-cysteine), chitosan-thioglycolic acid (chitosan-TGA), and thiolated PEG-g-PEI copolymer along with brij 35, myrj 52 and the well-established CYPP450 inhibitor verapamil were screened for their CYP3A4 and CYP2A6 inhibitory activity, and their IC(50) values were determined. Both enzyme inhibition assays were performed in 96-well microtiter plates. 7-Benzyloxy-4-(trifluoromethyl)-coumarin (BFC) and 7-hydroxycoumarin (7-HC) were used as fluorescent substrates in order to determine CYP3A4 and CYP2A6 catalytic activity, respectively. All investigated compounds inhibited CYP3A4 as well as CYP2A6 activity. All tested (thiolated) polymers were found to be more potent inhibitors of CYP3A4 than of CYP2A6 catalytic activity. Apart from verapamil that is a known CYP3A4 inhibitor, brij 35 and myrj 52 were explored as potent inhibitors of CYP3A4 and CYP2A6 catalytic activity. Among the tested polymers, the rank order for CYP3A4 inhibition was PAA-cysteine (100 kDa)>brij 35>thiolated PEG-g-PEI copolymer (16 kDa)>myrj 52>PAA (100 kDa)>PAA-cysteine (450 kDa)>verapamil>PAA (450 kDa)>chitosan-TGA (150 kDa)>chitosan (150 kDa). On the other hand, the rank order of CYP2A6 inhibition was brij 35>PAA-cysteine (100kDa)>chitosan-TGA (150 kDa)>PAA (100 kDa)>thiolated PEG-g-PEI copolymer (16 kDa)>PAA-cysteine (450 kDa)>chitosan (150 kDa)>verapamil>PAA (450 kDa)>myrj 52. Thus, this study suggests that (thiolated) polymers display a promising potential to inhibit cytochrome P450s activity and might turn out to be potentially valuable tools for improving the oral bioavailability of actively secreted compounds by avoiding intestinal metabolism.

  13. Irreversible enzyme inhibition kinetics and drug-drug interactions.

    PubMed

    Mohutsky, Michael; Hall, Stephen D

    2014-01-01

    This chapter describes the types of irreversible inhibition of drug-metabolizing enzymes and the methods commonly employed to quantify the irreversible inhibition and subsequently predict the extent and time course of clinically important drug-drug interactions.

  14. Foxp3+ T cells inhibit antitumor immune memory modulated by mTOR inhibition.

    PubMed

    Wang, Yanping; Sparwasser, Tim; Figlin, Robert; Kim, Hyung L

    2014-04-15

    Inhibition of mTOR signaling enhances antitumor memory lymphocytes. However, pharmacologic mTOR inhibition also enhances regulatory T-cell (Treg) activity. To counter this effect, Treg control was added to mTOR inhibition in preclinical models. Tregs were controlled with CD4-depleting antibodies because CD4 depletion has high translational potential and already has a well-established safety profile in patients. The antitumor activity of the combination therapy was CD8 dependent and controlled growth of syngeneic tumors even when an adoptive immunotherapy was not used. Lymphocytes resulting from the combination therapy could be transferred into naïve mice to inhibit aggressive growth of lung metastases. The combination therapy enhanced CD8 memory formation as determined by memory markers and functional studies of immune recall. Removal of FoxP3-expressing T lymphocytes was the mechanism underlying immunologic memory formation following CD4 depletion. This was confirmed using transgenic DEREG (depletion of regulatory T cells) mice to specifically remove Foxp3(+) T cells. It was further confirmed with reciprocal studies where stimulation of immunologic memory because of CD4 depletion was completely neutralized by adoptively transferring tumor-specific Foxp3(+) T cells. Also contributing to tumor control, Tregs that eventually recovered following CD4 depletion were less immunosuppressive. These results provide a rationale for further study of mTOR inhibition and CD4 depletion in patients.

  15. Allosteric Partial Inhibition of Monomeric Proteases. Sulfated Coumarins Induce Regulation, not just Inhibition, of Thrombin

    PubMed Central

    Verespy III, Stephen; Mehta, Akul Y.; Afosah, Daniel; Al-Horani, Rami A.; Desai, Umesh R.

    2016-01-01

    Allosteric partial inhibition of soluble, monomeric proteases can offer major regulatory advantages, but remains a concept on paper to date; although it has been routinely documented for receptors and oligomeric proteins. Thrombin, a key protease of the coagulation cascade, displays significant conformational plasticity, which presents an attractive opportunity to discover small molecule probes that induce sub-maximal allosteric inhibition. We synthesized a focused library of some 36 sulfated coumarins to discover two agents that display sub-maximal efficacy (~50%), high potency (<500 nM) and high selectivity for thrombin (>150-fold). Michaelis-Menten, competitive inhibition, and site-directed mutagenesis studies identified exosite 2 as the site of binding for the most potent sulfated coumarin. Stern-Volmer quenching of active site-labeled fluorophore suggested that the allosteric regulators induce intermediate structural changes in the active site as compared to those that display ~80–100% efficacy. Antithrombin inactivation of thrombin was impaired in the presence of the sulfated coumarins suggesting that allosteric partial inhibition arises from catalytic dysfunction of the active site. Overall, sulfated coumarins represent first-in-class, sub-maximal inhibitors of thrombin. The probes establish the concept of allosteric partial inhibition of soluble, monomeric proteins. This concept may lead to a new class of anticoagulants that are completely devoid of bleeding. PMID:27053426

  16. GTPase regulation: getting aRnd Rock and Rho inhibition.

    PubMed

    Chardin, Pierre

    2003-09-16

    Rnd proteins are atypical members of the Rho small G protein family that inhibit the formation of actomyosin contractile fibers via activation of RhoGAPs and inhibition of a Rho effector, the Ser/Thr kinase Rock. These mechanisms might be used to fine-tune Rho GTPase inhibition locally at sites where particular actin structures need to be made.

  17. Cellobionic acid inhibition of cellobiohydrolase I and cellobiose dehydrogenase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    End-product inhibition by cellobiose and glucose is a rate-limiting factor in cellulose hydrolysis by cellulases. While cellobiose and glucose inhibition have been extensively investigated, cellobionate inhibition has been minimally studied despite the discovery that accessory proteins such as cello...

  18. SIRT1 controls cell proliferation by regulating contact inhibition.

    PubMed

    Cho, Elizabeth H; Dai, Yan

    2016-09-16

    Contact inhibition keeps cell proliferation in check and serves as a built-in protection against cancer development by arresting cell division upon cell-cell contact. Yet the complete mechanism behind this anti-cancer process remains largely unclear. Here we present SIRT1 as a novel regulator of contact inhibition. SIRT1 performs a wide variety of functions in biological processes, but its involvement in contact inhibition has not been explored to date. We used NIH3T3 cells, which are sensitive to contact inhibition, and H460 and DU145 cancer cells, which lack contact inhibition, to investigate the relationship between SIRT1 and contact inhibition. We show that SIRT1 overexpression in NIH3T3 cells overcomes contact inhibition while SIRT1 knockdown in cancer cells restores their lost contact inhibition. Moreover, we demonstrate that p27 protein expression is controlled by SIRT1 in contact inhibition. Overall, our findings underline the critical role of SIRT1 in contact inhibition and suggest SIRT1 inhibition as a potential strategy to suppress cancer cell growth by restoring contact inhibition.

  19. Eye Blink Startle Responses in Behaviorally Inhibited and Uninhibited Children

    ERIC Educational Resources Information Center

    van Brakel, Anna M. L.; Muris, Peter; Derks, Wendy

    2006-01-01

    The present study examined the startle reflex as a physiological marker of behavioral inhibition. Participants were 7 to 12-year-old children who had been previously identified as inhibited or uninhibited as part of an ongoing longitudinal study on the role of behavioral inhibition in the development of anxiety disorders. Analysis of their scores…

  20. Interferon-γ Inhibits Ebola Virus Infection

    PubMed Central

    Rhein, Bethany A.; Powers, Linda S.; Rogers, Kai; Anantpadma, Manu; Singh, Brajesh K.; Sakurai, Yasuteru; Bair, Thomas; Miller-Hunt, Catherine; Sinn, Patrick; Davey, Robert A.

    2015-01-01

    Ebola virus outbreaks, such as the 2014 Makona epidemic in West Africa, are episodic and deadly. Filovirus antivirals are currently not clinically available. Our findings suggest interferon gamma, an FDA-approved drug, may serve as a novel and effective prophylactic or treatment option. Using mouse-adapted Ebola virus, we found that murine interferon gamma administered 24 hours before or after infection robustly protects lethally-challenged mice and reduces morbidity and serum viral titers. Furthermore, we demonstrated that interferon gamma profoundly inhibits Ebola virus infection of macrophages, an early cellular target of infection. As early as six hours following in vitro infection, Ebola virus RNA levels in interferon gamma-treated macrophages were lower than in infected, untreated cells. Addition of the protein synthesis inhibitor, cycloheximide, to interferon gamma-treated macrophages did not further reduce viral RNA levels, suggesting that interferon gamma blocks life cycle events that require protein synthesis such as virus replication. Microarray studies with interferon gamma-treated human macrophages identified more than 160 interferon-stimulated genes. Ectopic expression of a select group of these genes inhibited Ebola virus infection. These studies provide new potential avenues for antiviral targeting as these genes that have not previously appreciated to inhibit negative strand RNA viruses and specifically Ebola virus infection. As treatment of interferon gamma robustly protects mice from lethal Ebola virus infection, we propose that interferon gamma should be further evaluated for its efficacy as a prophylactic and/or therapeutic strategy against filoviruses. Use of this FDA-approved drug could rapidly be deployed during future outbreaks. PMID:26562011

  1. Ventral hippocampal neurons inhibit postprandial energy intake.

    PubMed

    Hannapel, Reilly C; Henderson, Yoko H; Nalloor, Rebecca; Vazdarjanova, Almira; Parent, Marise B

    2017-03-01

    Evidence suggests that the memory of a recently ingested meal limits subsequent intake. Given that ventral hippocampal (vHC) neurons are involved in memory and energy intake, the present experiment tested the hypothesis that vHC neurons contribute to the formation of a memory of a meal and inhibit energy intake during the postprandial period. We tested (1) whether pharmacological inactivation of vHC neurons during the period following a sucrose meal, when the memory of the meal would be undergoing consolidation, accelerates the onset of the next sucrose meal and increases intake and (2) whether sucrose intake increases vHC expression of the synaptic plasticity marker activity-regulated cytoskeletal-associated protein (Arc). Adult male Sprague-Dawley rats were trained to consume a 32% sucrose solution daily at the same time and location. On the experimental day, the rats were given intra-vHC infusions of the GABAA receptor agonist muscimol or vehicle after they finished their first sucrose meal. Compared to vehicle infusions, postmeal intra-vHC muscimol infusions decreased the latency to the next sucrose meal, increased the amount of sucrose consumed during that meal, increased the total number of sucrose meals and the total amount of sucrose ingested. In addition, rats that consumed sucrose had higher levels of Arc expression in both vHC CA1 and CA3 subfields than cage control rats. Collectively, these findings are the first to show that vHC neurons inhibit energy intake during the postprandial period and support the hypothesis that vHC neurons form a memory of a meal and inhibit subsequent intake. © 2016 Wiley Periodicals, Inc.

  2. Reliability of Transcallosal Inhibition in Healthy Adults

    PubMed Central

    Fleming, Melanie K.; Newham, Di J.

    2017-01-01

    Transcallosal inhibition (TCI), assessed using transcranial magnetic stimulation, can provide insight into the neurophysiology of aging and of neurological disorders such as stroke. However, the reliability of TCI using the ipsilateral silent period (iSP) has not been formally assessed, despite its use in longitudinal studies. This study aimed to determine the reliability of iSP onset latency, duration and depth in healthy young and older adults. A sample of 18 younger (mean age 27.7 years, range: 19–42) and 13 older healthy adults (mean age 68.1 years, range: 58–79) attended four sessions whereby the iSP was measured from the first dorsal interosseous (FDI) muscle of each hand. 20 single pulse stimuli were delivered to each primary motor cortex at 80% maximum stimulator output while the participant maintained an isometric contraction of the ipsilateral FDI. The average onset latency, duration of the iSP, and depth of inhibition relative to baseline electromyography activity was calculated for each hand in each session. Intraclass correlation coefficients (ICCs) were calculated for all four sessions, or the first two sessions only. For iSP onset latency the reliability ranged from poor to good. For iSP duration there was moderate to good reliability (ICC > 0.6). Depth of inhibition demonstrated variation in reproducibility depending on which hand was assessed and whether two or four sessions were compared. Bland and Altman analyses showed wide limits of agreement between the first two sessions, particularly for iSP depth. However, there was no systematic pattern to the variability. These results indicate that although iSP duration is reliable in healthy adults, changes in longitudinal studies should be interpreted with caution, particularly for iSP depth. Future studies are needed to determine reliability in clinical populations. PMID:28119588

  3. Interferon-γ Inhibits Ebola Virus Infection.

    PubMed

    Rhein, Bethany A; Powers, Linda S; Rogers, Kai; Anantpadma, Manu; Singh, Brajesh K; Sakurai, Yasuteru; Bair, Thomas; Miller-Hunt, Catherine; Sinn, Patrick; Davey, Robert A; Monick, Martha M; Maury, Wendy

    2015-01-01

    Ebola virus outbreaks, such as the 2014 Makona epidemic in West Africa, are episodic and deadly. Filovirus antivirals are currently not clinically available. Our findings suggest interferon gamma, an FDA-approved drug, may serve as a novel and effective prophylactic or treatment option. Using mouse-adapted Ebola virus, we found that murine interferon gamma administered 24 hours before or after infection robustly protects lethally-challenged mice and reduces morbidity and serum viral titers. Furthermore, we demonstrated that interferon gamma profoundly inhibits Ebola virus infection of macrophages, an early cellular target of infection. As early as six hours following in vitro infection, Ebola virus RNA levels in interferon gamma-treated macrophages were lower than in infected, untreated cells. Addition of the protein synthesis inhibitor, cycloheximide, to interferon gamma-treated macrophages did not further reduce viral RNA levels, suggesting that interferon gamma blocks life cycle events that require protein synthesis such as virus replication. Microarray studies with interferon gamma-treated human macrophages identified more than 160 interferon-stimulated genes. Ectopic expression of a select group of these genes inhibited Ebola virus infection. These studies provide new potential avenues for antiviral targeting as these genes that have not previously appreciated to inhibit negative strand RNA viruses and specifically Ebola virus infection. As treatment of interferon gamma robustly protects mice from lethal Ebola virus infection, we propose that interferon gamma should be further evaluated for its efficacy as a prophylactic and/or therapeutic strategy against filoviruses. Use of this FDA-approved drug could rapidly be deployed during future outbreaks.

  4. Taste Coding after Selective Inhibition by Chlorhexidine

    PubMed Central

    Wang, Miao-Fen; Marks, Lawrence E.

    2009-01-01

    Coding of the complex tastes of ionic stimuli in humans was studied by combining taste confusion matrix (TCM) methodology and treatment with chlorhexidine gluconate. The TCM evaluates discrimination of multiple stimuli simultaneously. Chlorhexidine, a bis-biguanide antiseptic, reversibly inhibits salty taste and tastes of a subset of bitter stimuli, including quinine hydrochloride. Identifications of salty (NaCl, “salt”), bitter (quinine·HCl, “quinine”), sweet (sucrose, “sugar”), and sour (citric acid, “acid”) prototypes, alone and as components of binary mixtures, were measured under 4 conditions. One was a water-rinse control and the others had the salt and quinine tastes progressively reduced by treatment with 1 mM chlorhexidine, 3 mM chlorhexidine, and ultimately to zero by elimination of NaCl and quinine·HCl. Treatment with chlorhexidine perturbed identification of salt more than quinine; both were thereafter more often confused with “water” and unidentified when mixed with sucrose or citric acid. All pairwise discriminations that depended on the tastes of NaCl and quinine·HCl deteriorated, and although H2O was mistakenly identified as quinine after chlorhexidine, this may have been a decisional bias. Other confusions reflected “unprompted mixture analysis” and an obscuring of salt taste by a less-inhibited stronger quinine or sugar or acid tastes in mixtures. Partial inhibition of the tastes of NaCl and quinine·HCl by chlorhexidine was considered in the context of multiple receptors for the 2 compounds. Discrimination among prototypic stimuli with varying strengths was consistent with a gustatory system that evaluates a small number of independent tastes. PMID:19703921

  5. Center-Surround Inhibition in Working Memory.

    PubMed

    Kiyonaga, Anastasia; Egner, Tobias

    2016-01-11

    Directing visual attention toward a particular feature or location in the environment suppresses processing of nearby stimuli [1-4]. Echoing the center-surround organization of retinal ganglion cell receptive fields [5], and biasing of competitive local neuronal dynamics in favor of task-relevant stimuli [6], this "inhibitory surround" attention mechanism accentuates the demarcation between task-relevant and irrelevant items. Here, we show that internally maintaining a color stimulus in working memory (WM), rather than visually attending the stimulus in the external environment, produces an analogous pattern of inhibition for stimuli that are nearby in color space. Replicating a well-known effect of attentional capture by stimuli that match WM content [7], visual attention was biased toward (task-irrelevant) stimuli that exactly matched a WM item. This bias was curtailed, however, for stimuli that were very similar to the WM content (i.e., within the inhibitory zone surrounding the focus of WM) and recovered for less similar stimuli (i.e., beyond the bounds of the inhibitory surround). Moreover, the expression of this inhibition effect was positively associated with WM performance across observers. In a second experiment, inhibition also occurred between two similar items simultaneously held in WM. This suggests that maintenance in WM is characterized by an excitatory peak centered on the focus of (internal) attention, surrounded by an inhibitory zone to limit interference by irrelevant and confusable representations. Here, thus, we show for the first time that the same center-surround selection mechanism that focuses visual attention on sensory stimuli also selectively maintains internally activated representations in WM.

  6. Inhibition by Somatostatin Interneurons in Olfactory Cortex

    PubMed Central

    Large, Adam M.; Kunz, Nicholas A.; Mielo, Samantha L.; Oswald, Anne-Marie M.

    2016-01-01

    Inhibitory circuitry plays an integral role in cortical network activity. The development of transgenic mouse lines targeting unique interneuron classes has significantly advanced our understanding of the functional roles of specific inhibitory circuits in neocortical sensory processing. In contrast, considerably less is known about the circuitry and function of interneuron classes in piriform cortex, a paleocortex responsible for olfactory processing. In this study, we sought to utilize transgenic technology to investigate inhibition mediated by somatostatin (SST) interneurons onto pyramidal cells (PCs), parvalbumin (PV) interneurons, and other interneuron classes. As a first step, we characterized the anatomical distributions and intrinsic properties of SST and PV interneurons in four transgenic lines (SST-cre, GIN, PV-cre, and G42) that are commonly interbred to investigate inhibitory connectivity. Surprisingly, the distributions SST and PV cell subtypes targeted in the GIN and G42 lines were sparse in piriform cortex compared to neocortex. Moreover, two-thirds of interneurons recorded in the SST-cre line had electrophysiological properties similar to fast spiking (FS) interneurons rather than regular (RS) or low threshold spiking (LTS) phenotypes. Nonetheless, like neocortex, we find that SST-cells broadly inhibit a number of unidentified interneuron classes including putatively identified PV cells and surprisingly, other SST cells. We also confirm that SST-cells inhibit pyramidal cell dendrites and thus, influence dendritic integration of afferent and recurrent inputs to the piriform cortex. Altogether, our findings suggest that SST interneurons play an important role in regulating both excitation and the global inhibitory network during olfactory processing. PMID:27582691

  7. Cannabidiol inhibits angiogenesis by multiple mechanisms

    PubMed Central

    Solinas, M; Massi, P; Cantelmo, AR; Cattaneo, MG; Cammarota, R; Bartolini, D; Cinquina, V; Valenti, M; Vicentini, LM; Noonan, DM; Albini, A; Parolaro, D

    2012-01-01

    BACKGROUND AND PURPOSE Several studies have demonstrated anti-proliferative and pro-apoptotic actions of cannabinoids on various tumours, together with their anti-angiogenic properties. The non-psychoactive cannabinoid cannabidiol (CBD) effectively inhibits the growth of different types of tumours in vitro and in vivo and down-regulates some pro-angiogenic signals produced by glioma cells. As its anti-angiogenic properties have not been thoroughly investigated to date, and given its very favourable pharmacological and toxicological profile, here, we evaluated the ability of CBD to modulate tumour angiogenesis. EXPERIMENTAL APPROACH Firstly, we evaluated the effect of CBD on human umbilical vein endothelial cell (HUVEC) proliferation and viability – through [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and FACS analysis – and in vitro motility – both in a classical Boyden chamber test and in a wound-healing assay. We next investigated CBD effects on different angiogenesis-related proteins released by HUVECs, using an angiogenesis array kit and an ELISA directed at MMP2. Then we evaluated its effects on in vitro angiogenesis in treated HUVECs invading a Matrigel layer and in HUVEC spheroids embedded into collagen gels, and further characterized its effects in vivo using a Matrigel sponge model of angiogenesis in C57/BL6 mice. KEY RESULTS CBD induced HUVEC cytostasis without inducing apoptosis, inhibited HUVEC migration, invasion and sprouting in vitro, and angiogenesis in vivo in Matrigel sponges. These effects were associated with the down-modulation of several angiogenesis-related molecules. CONCLUSIONS AND IMPLICATIONS This study reveals that CBD inhibits angiogenesis by multiple mechanisms. Its dual effect on both tumour and endothelial cells supports the hypothesis that CBD has potential as an effective agent in cancer therapy. PMID:22624859

  8. Inhibiting bacterial toxins by channel blockage.

    PubMed

    Bezrukov, Sergey M; Nestorovich, Ekaterina M

    2016-03-01

    Emergent rational drug design techniques explore individual properties of target biomolecules, small and macromolecule drug candidates, and the physical forces governing their interactions. In this minireview, we focus on the single-molecule biophysical studies of channel-forming bacterial toxins that suggest new approaches for their inhibition. We discuss several examples of blockage of bacterial pore-forming and AB-type toxins by the tailor-made compounds. In the concluding remarks, the most effective rationally designed pore-blocking antitoxins are compared with the small-molecule inhibitors of ion-selective channels of neurophysiology.

  9. Tooth brushing inhibits oral bacteria in dogs.

    PubMed

    Watanabe, Kazuhiro; Hayashi, Kotaro; Kijima, Saku; Nonaka, Chie; Yamazoe, Kazuaki

    2015-10-01

    In this study, scaling, polishing and daily tooth brushing were performed in 20 beagle dogs, and the number of oral bacteria was determined using a bacterial counter. The dogs were randomized into the scaling (S), scaling + polishing (SP), scaling + tooth daily brushing (SB) and scaling + polishing + tooth daily brushing (SPB) groups. Samples were collected from the buccal surface of the maxillary fourth premolars of the dogs immediately after scaling and every week thereafter from weeks 1 to 8. Throughout the study, the number of bacteria was significantly lower in the SB and SPB groups compared with the S group. The findings suggest that daily tooth brushing inhibited oral bacterial growth in the dogs.

  10. Emergence of clustering: Role of inhibition

    NASA Astrophysics Data System (ADS)

    Dwivedi, Sanjiv K.; Jalan, Sarika

    2014-09-01

    Though biological and artificial complex systems having inhibitory connections exhibit a high degree of clustering in their interaction pattern, the evolutionary origin of clustering in such systems remains a challenging problem. Using genetic algorithm we demonstrate that inhibition is required in the evolution of clique structure from primary random architecture, in which the fitness function is assigned based on the largest eigenvalue. Further, the distribution of triads over nodes of the network evolved from mixed connections reveals a negative correlation with its degree providing insight into origin of this trend observed in real networks.

  11. Inhibiting bacterial toxins by channel blockage

    PubMed Central

    Bezrukov, Sergey M.; Nestorovich, Ekaterina M.

    2015-01-01

    Emergent rational drug design techniques explore individual properties of target biomolecules, small and macromolecule drug candidates, and the physical forces governing their interactions. In this minireview, we focus on the single-molecule biophysical studies of channel-forming bacterial toxins that suggest new approaches for their inhibition. We discuss several examples of blockage of bacterial pore-forming and AB-type toxins by the tailor-made compounds. In the concluding remarks, the most effective rationally designed pore-blocking antitoxins are compared with the small-molecule inhibitors of ion-selective channels of neurophysiology. PMID:26656888

  12. Saw palmetto ethanol extract inhibits adipocyte differentiation.

    PubMed

    Villaverde, Nicole; Galvis, Adriana; Marcano, Adriana; Priestap, Horacio A; Bennett, Bradley C; Barbieri, M Alejandro

    2013-07-01

    The fruits of saw palmetto have been used for the treatment of a variety of urinary and reproductive system problems. In this study we investigated whether the fruit extracts affect in vitro adipogenesis. Saw palmetto ethanol extract inhibited the lipid droplet accumulation by induction media in a dose-dependent manner, and it also attenuated the protein expressions of C-EBPα and PPARγ. Phosphorylation of Erk1/2 and Akt1 were also decreased by saw palmetto ethanol extract. This report suggests that saw palmetto extracts selectively affect the adipocyte differentiation through the modulation of several key factors that play a critical role during adipogenesis.

  13. Formation and inhibition of photochemical smog

    SciTech Connect

    Heicklen, J.

    1987-01-01

    Photochemical smog is caused by a free-radical chain mechanism which converts NO to NO/sub 2/. The NO/sub 2/ further reacts to produce ozone, nitric acid, and peracylnitrates. This chain mechanism can be inhibited by suitable free-radical scavengers. The chemistry and toxicology of one such free-radical scavenger, diethylhydroxylamine, has been studied in depth. It has been shown to be effective, safe, and practical for use in urban atmospheres to prevent photochemical smog formation. 42 references.

  14. Aminopeptidase from Brevibacterium linens: activation and inhibition.

    PubMed

    Foissy, H

    1978-04-18

    Activation and inhibition of a purified aminopeptidase from Brevibacterium linens was investigated using L-alpha-leucyl-4-nitroanilide and L-leucyl-L-leucine as substrates. The enzyme was activated by cobalt, provided that the enzyme was preincubated with the metal. Strong inhibitory effects were derived from heavy metals, metal-complexing compounds, reducing agents, the modification of aromatic amino acids, and the presence of hydrophobic substances or certain amino acids in the test mixtures. Supposing that this B. linens aminopeptidase plays a part during surface-ripening of cheeses, possible consequences of specific technological conditions for its activity are discussed.

  15. Multiple components of ipsilaterally evoked inhibition in the inferior colliculus.

    PubMed

    Klug, A; Bauer, E E; Pollak, G D

    1999-08-01

    The central nucleus of the inferior colliculus (ICc) receives a large number of convergent inputs that are both excitatory and inhibitory. Although excitatory inputs typically are evoked by stimulation of the contralateral ear, inhibitory inputs can be recruited by either ear. Here we evaluate ipsilaterally evoked inhibition in single ICc cells in awake Mexican free-tailed bats. The principal question we addressed concerns the degree to which ipsilateral inhibition at the ICc suppresses contralaterally evoked discharges and thus creates the excitatory-inhibitory (EI) properties of ICc neurons. To study ipsilaterally evoked inhibition, we iontophoretically applied excitatory neurotransmitters and visualized the ipsilateral inhibition as a gap in the carpet of background activity evoked by the transmitters. Ipsilateral inhibition was seen in 86% of ICc cells. The inhibition in most cells had both glycinergic and GABAergic components that could be blocked by the iontophoretic application of bicuculline and strychnine. In 80% of the cells that were inhibited, the ipsilateral inhibition and contralateral excitation were temporally coincident. In many of these cells, the ipsilateral inhibition suppressed contralateral discharges and thus generated the cell's EI property in the ICc. In other cells, the ipsilateral inhibition was coincident with the initial portion of the excitation, but the inhibition was only 2-4 ms in duration and suppressed only the first few contralaterally evoked discharges. The suppression was so slight that it often could not be detected as a decrease in the spike count generated by increasing ipsilateral intensities. Twenty percent of the cells that expressed inhibition, however, had inhibitory latencies that were longer than the excitatory latencies. In these neurons, the inhibition arrived too late to suppress most or any of the discharges. Finally, in the majority of cells, the ipsilateral inhibition persisted for tens of milliseconds beyond

  16. Optogenetic and chemogenetic strategies for sustained inhibition of pain

    PubMed Central

    Iyer, Shrivats M.; Vesuna, Sam; Ramakrishnan, Charu; Huynh, Karen; Young, Stephanie; Berndt, Andre; Lee, Soo Yeun; Gorini, Christopher J.; Deisseroth, Karl; Delp, Scott L.

    2016-01-01

    Spatially targeted, genetically-specific strategies for sustained inhibition of nociceptors may help transform pain science and clinical management. Previous optogenetic strategies to inhibit pain have required constant illumination, and chemogenetic approaches in the periphery have not been shown to inhibit pain. Here, we show that the step-function inhibitory channelrhodopsin, SwiChR, can be used to persistently inhibit pain for long periods of time through infrequent transdermally delivered light pulses, reducing required light exposure by >98% and resolving a long-standing limitation in optogenetic inhibition. We demonstrate that the viral expression of the hM4D receptor in small-diameter primary afferent nociceptor enables chemogenetic inhibition of mechanical and thermal nociception thresholds. Finally, we develop optoPAIN, an optogenetic platform to non-invasively assess changes in pain sensitivity, and use this technique to examine pharmacological and chemogenetic inhibition of pain. PMID:27484850

  17. A Comparator View of Pavlovian and Differential Inhibition

    PubMed Central

    Urcelay, Gonzalo P.; Miller, Ralph R.

    2007-01-01

    In 3 experiments using rats as subjects, the authors varied trial spacing to investigate the conditions under which Pavlovian and differential inhibition are observed. Experiment 1 compared Pavlovian and differential inhibition with spaced training trials. Spaced trials resulted in only the Pavlovian inhibitor passing both summation and retardation tests. Conversely, Experiment 2 compared these 2 types of inhibition with massed training trials. This training resulted in only the differential inhibitor passing both tests for conditioned inhibition. Finally, in Experiment 3 all subjects experienced Pavlovian inhibition training with massed trials. Although this training by itself did not result in behavior indicative of inhibition, subjects that also experienced posttraining extinction of the training context did pass both tests for inhibition. Overall, these results are anticipated by the extended comparator hypothesis (Denniston, Savastano, & Miller, 2001) but are problematic for most contemporary associative learning theories. PMID:16834494

  18. A comparator view of Pavlovian and differential inhibition.

    PubMed

    Urcelay, Gonzalo P; Miller, Ralph R

    2006-07-01

    In 3 experiments using rats as subjects, the authors varied trial spacing to investigate the conditions under which Pavlovian and differential inhibition are observed. Experiment 1 compared Pavlovian and differential inhibition with spaced training trials. Spaced trials resulted in only the Pavlovian inhibitor passing both summation and retardation tests. Conversely, Experiment 2 compared these 2 types of inhibition with massed training trials. This training resulted in only the differential inhibitor passing both tests for conditioned inhibition. Finally, in Experiment 3 all subjects experienced Pavlovian inhibition training with massed trials. Although this training by itself did not result in behavior indicative of inhibition, subjects that also experienced posttraining extinction of the training context did pass both tests for inhibition. Overall, these results are anticipated by the extended comparator hypothesis (Denniston, Savastano, & Miller, 2001) but are problematic for most contemporary associative learning theories.

  19. Metal ion substrate inhibition of ferrochelatase.

    PubMed

    Hunter, Gregory A; Sampson, Matthew P; Ferreira, Gloria C

    2008-08-29

    Ferrochelatase catalyzes the insertion of ferrous iron into protoporphyrin IX to form heme. Robust kinetic analyses of the reaction mechanism are complicated by the instability of ferrous iron in aqueous solution, particularly at alkaline pH values. At pH 7.00 the half-life for spontaneous oxidation of ferrous ion is approximately 2 min in the absence of metal complexing additives, which is sufficient for direct comparisons of alternative metal ion substrates with iron. These analyses reveal that purified recombinant ferrochelatase from both murine and yeast sources inserts not only ferrous iron but also divalent cobalt, zinc, nickel, and copper into protoporphyrin IX to form the corresponding metalloporphyrins but with considerable mechanistic variability. Ferrous iron is the preferred metal ion substrate in terms of apparent k(cat) and is also the only metal ion substrate not subject to severe substrate inhibition. Substrate inhibition occurs in the order Cu(2+) > Zn(2+) > Co(2+) > Ni(2+) and can be alleviated by the addition of metal complexing agents such as beta-mercaptoethanol or imidazole to the reaction buffer. These data indicate the presence of two catalytically significant metal ion binding sites that may coordinately regulate a selective processivity for the various potential metal ion substrates.

  20. Effects of renin inhibition in systemic hypertension.

    PubMed

    Anderson, P W; Do, Y S; Schambelan, M; Horton, R; Boger, R S; Luther, R R; Hsueh, W A

    1990-12-01

    The effect of the direct renin inhibitor enalkiren (Abbott Laboratories) was examined in 8 healthy patients with essential hypertension. With an unrestricted sodium diet, plasma renin concentration was inhibited within 10 minutes by intravenous enalkiren and remained essentially undetectable for greater than or equal to 6 hours (11.9 +/- 4 to 1.0 +/- 0.6 ng angiotensin I/ml/hour, p less than 0.05). Mean arterial blood pressure declined gradually (108 +/- 5 to 84 +/- 4 mm Hg, p = 0.02), as did plasma aldosterone concentration (14.4 +/- 3.8 to 4.4 +/- 0.8 ng/dl, p = 0.03), whereas plasma immunoreactive active renin concentration increased progressively (35 +/- 14 to 160 +/- 60 pg/ml, p greater than 0.05). Urinary excretion of the stable metabolite of prostacyclin (6-keto-prostaglandin F1 alpha) decreased slightly, but not significantly (42 +/- 10 to 33 +/- 11 ng/g creatinine, p = 0.13). The addition of a diuretic decreased baseline blood pressure and increased baseline plasma renin and aldosterone values. Blood pressure responses to enalkiren were slightly (though not significantly) greater than those observed before diuretic administration. We conclude that enalkiren is effective in decreasing blood pressure and in inhibiting the renin system, without significantly altering urinary prostacyclin excretion, in patients with essential hypertension. These results suggest that the renin system contributes to the maintenance of elevated blood pressure in some patients with essential hypertension.

  1. Understanding biocatalyst inhibition by carboxylic acids.

    PubMed

    Jarboe, Laura R; Royce, Liam A; Liu, Ping

    2013-09-03

    Carboxylic acids are an attractive biorenewable chemical in terms of their flexibility and usage as precursors for a variety of industrial chemicals. It has been demonstrated that such carboxylic acids can be fermentatively produced using engineered microbes, such as Escherichia coli and Saccharomyces cerevisiae. However, like many other attractive biorenewable fuels and chemicals, carboxylic acids become inhibitory to these microbes at concentrations below the desired yield and titer. In fact, their potency as microbial inhibitors is highlighted by the fact that many of these carboxylic acids are routinely used as food preservatives. This review highlights the current knowledge regarding the impact that saturated, straight-chain carboxylic acids, such as hexanoic, octanoic, decanoic, and lauric acids can have on E. coli and S. cerevisiae, with the goal of identifying metabolic engineering strategies to increase robustness. Key effects of these carboxylic acids include damage to the cell membrane and a decrease of the microbial internal pH. Certain changes in cell membrane properties, such as composition, fluidity, integrity, and hydrophobicity, and intracellular pH are often associated with increased tolerance. The availability of appropriate exporters, such as Pdr12, can also increase tolerance. The effect on metabolic processes, such as maintaining appropriate respiratory function, regulation of Lrp activity and inhibition of production of key metabolites such as methionine, are also considered. Understanding the mechanisms of biocatalyst inhibition by these desirable products can aid in the engineering of robust strains with improved industrial performance.

  2. Inhibition of saccades elicits attentional suppression.

    PubMed

    Dhawan, Saurabh; Deubel, Heiner; Jonikaitis, Donatas

    2013-05-17

    Visuospatial attention has been shown to have a central role in planning and generation of saccades but what role, if any, it plays in inhibition of saccades remains unclear. In this study, we used an oculomotor delayed match- or nonmatch-to-sample task in which a cued location has to be encoded and memorized for one of two very different goals-to plan a saccade to it or to avoid making a saccade to it. We measured the spatial allocation of attention during the delay and found that while marking a location as a future saccade target resulted in an attentional benefit at that location, marking it as forbidden to saccades led to an attentional cost. Additionally, saccade trajectories were found to deviate away more from the "don't look" location than from a saccade-irrelevant distractor confirming greater inhibition of an actively forbidden location in oculomotor programming. Our finding that attention is suppressed at locations forbidden to saccades confirms and complements the claim of a selective and obligatory coupling between saccades and attention-saccades at the memorized location could neither be planned nor suppressed independent of a corresponding effect on attentional performance.

  3. Response inhibition and attentional control in anxiety.

    PubMed

    Pacheco-Unguetti, Antonia Pilar; Acosta, Alberto; Lupiáñez, Juan; Román, Naiker; Derakshan, Nazanin

    2012-01-01

    Traditionally, anxiety has been associated with a selective attentional bias for threat and a decreased capacity in attentional control. In two different experiments, we investigated whether individuals with different levels of self-reported state anxiety (Experiment 1) and induced anxiety (Experiment 2) had impaired response inhibition processes (attentional control deficit) as characterized by a different response style in the presence of negative stimuli under low and high perceptual load conditions. A go/no-go paradigm with emotional distractors (angry, happy, and neutral faces) was used to provide measures of perceptual sensitivity, inhibition, and response style. Our findings showed that perceptual sensitivity, as assessed by the d' parameter of signal detection theory, was reduced in all participants for angry faces under low perceptual load, where enough perceptual resources were available to be attracted by distractors. Importantly, despite similar perceptual sensitivity, the beta parameter indicated that high state anxiety individuals in both experiments were less flexible at adjusting to task demands in the presence of angry face distractors by adopting a stricter criterion. Implications of findings are discussed within current models of attentional control in anxiety.

  4. Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis.

    PubMed

    Szkudlarek-Mikho, Maria; Saunders, Rudel A; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

    2012-11-30

    The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor γ. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy.

  5. Calcineurin/NFAT signalling inhibits myeloid haematopoiesis

    PubMed Central

    Fric, Jan; Lim, Clarice X F; Koh, Esther G L; Hofmann, Benjamin; Chen, Jinmiao; Tay, Hock Soon; Isa, Siti Aminah Bte Mohammad; Mortellaro, Alessandra; Ruedl, Christiane; Ricciardi-Castagnoli, Paola

    2012-01-01

    Nuclear factor of activated T cells (NFAT) comprises a family of transcription factors that regulate T cell development, activation and differentiation. NFAT signalling can also mediate granulocyte and dendritic cell (DC) activation, but it is unknown whether NFAT influences their development from progenitors. Here, we report a novel role for calcineurin/NFAT signalling as a negative regulator of myeloid haematopoiesis. Reconstituting lethally irradiated mice with haematopoietic stem cells expressing an NFAT-inhibitory peptide resulted in enhanced development of the myeloid compartment. Culturing bone marrow cells in media supplemented with Flt3-L in the presence of the calcineurin/NFAT inhibitor Cyclosporin A increased numbers of differentiated DC. Global gene expression analysis of untreated DC and NFAT-inhibited DC revealed differential expression of transcripts that regulate cell cycle and apoptosis. In conclusion, these results provide evidence that calcineurin/NFAT signalling negatively regulates myeloid lineage development. The finding that inhibition of NFAT enhances myeloid development provides a novel insight into understanding how the treatment with drugs targeting calcineurin/NFAT signalling influence the homeostasis of the innate immune system. PMID:22311511

  6. In search of lost presynaptic inhibition.

    PubMed

    Rudomin, Pablo

    2009-06-01

    This chapter presents an historical review on the development of some of the main findings on presynaptic inhibition. Particular attention is given to recent studies pertaining the differential GABAa control of the synaptic effectiveness of muscle, cutaneous and articular afferents, to some of the problems arising with the identification of the interneurons mediating the GABAergic depolarization of primary afferents (PAD) of muscle afferents, on the influence of the spontaneous activity of discrete sets of dorsal horn neurons on the pathways mediating PAD of muscle and cutaneous afferents, and to the unmasking of the cutaneous-evoked responses in the lumbosacral spinal cord and associated changes in tonic PAD that follow acute and chronic section of cutaneous nerves. The concluding remarks are addressed to several issues that need to be considered to have a better understanding of the functional role of presynaptic inhibition and PAD on motor performance and sensory processing and on their possible contribution to the shaping of a higher coherence between the cortically programmed and the executed movements.

  7. Tonic inhibition of chemotaxis in human plasma

    PubMed Central

    Malawista, Stephen E.; de Boisfleury Chevance, Anne; van Damme, Jo; Serhan, Charles N.

    2008-01-01

    We found exaggerated chemotaxis in plasma treated with EDTA and thought that the EDTA might itself be inhibiting a tonic inhibitor(s) of chemotaxis. Our plasma fractionations suggested that evidence should be sought for a lipid moiety carrying this activity, and on spectrometry (LC-MS-MS together with GC-MS analyses), the biologically active but not the inactive fraction contained oleic and arachidonic acids. Because fatty acids are largely protein bound, we flooded plasma preparations with delipidated albumin, reasoning that it would bind enough fatty acids, including inhibitory ones, to counter their tonic inhibition. Indeed, we observed dramatic increases in chemotaxis. Hence, adding delipidated albumin to plasma has a similar effect to that of adding EDTA—amplification of the chemotactic response. Oleic acid in physiologic concentrations diminishes the magnifying effects of both EDTA and of delipidated albumin, and in fact diminishes the chemotactic response even without the presence of the amplifiers of chemotaxis. In contrast, arachidonic acid amplifies further the effect of EDTA but not of delipidated albumin, and this augmentation appears to be caused by an EDTA-dependent enrichment of the chemotactic gradient with leukotriene B4 (LTB4). We conclude that oleic acid, the blood levels of which vary among individuals, is at least one tonic inhibitor of chemotaxis in plasma. PMID:18997012

  8. Inhibition Of Washed Sludge With Sodium Nitrite

    SciTech Connect

    Congdon, J. W.; Lozier, J. S.

    2012-09-25

    This report describes the results of electrochemical tests used to determine the relationship between the concentration of the aggressive anions in washed sludge and the minimum effective inhibitor concentration. Sodium nitrate was added as the inhibitor because of its compatibility with the DWPF process. A minimum of 0.05M nitrite is required to inhibit the washed sludge simulant solution used in this study. When the worst case compositions and safety margins are considered, it is expected that a minimum operating limit of nearly 0.1M nitrite will be specified. The validity of this limit is dependent on the accuracy of the concentrations and solubility splits previously reported. Sodium nitrite additions to obtain 0.1M nitrite concentrations in washed sludge will necessitate the additional washing of washed precipitate in order to decrease its sodium nitrite inhibitor requirements sufficiently to remain below the sodium limits in the feed to the DWPF. Nitrite will be the controlling anion in "fresh" washed sludge unless the soluble chloride concentration is about ten times higher than predicted by the solubility splits. Inhibition of "aged" washed sludge will not be a problem unless significant chloride dissolution occurs during storage. It will be very important tomonitor the composition of washed sludge during processing and storage.

  9. Oxidation inhibits iron-induced blood coagulation.

    PubMed

    Pretorius, Etheresia; Bester, Janette; Vermeulen, Natasha; Lipinski, Boguslaw

    2013-01-01

    Blood coagulation under physiological conditions is activated by thrombin, which converts soluble plasma fibrinogen (FBG) into an insoluble clot. The structure of the enzymatically-generated clot is very characteristic being composed of thick fibrin fibers susceptible to the fibrinolytic degradation. However, in chronic degenerative diseases, such as atherosclerosis, diabetes mellitus, cancer, and neurological disorders, fibrin clots are very different forming dense matted deposits (DMD) that are not effectively removed and thus create a condition known as thrombosis. We have recently shown that trivalent iron (ferric ions) generates hydroxyl radicals, which subsequently convert FBG into abnormal fibrin clots in the form of DMDs. A characteristic feature of DMDs is their remarkable and permanent resistance to the enzymatic degradation. Therefore, in order to prevent thrombotic incidences in the degenerative diseases it is essential to inhibit the iron-induced generation of hydroxyl radicals. This can be achieved by the pretreatment with a direct free radical scavenger (e.g. salicylate), and as shown in this paper by the treatment with oxidizing agents such as hydrogen peroxide, methylene blue, and sodium selenite. Although the actual mechanism of this phenomenon is not yet known, it is possible that hydroxyl radicals are neutralized by their conversion to the molecular oxygen and water, thus inhibiting the formation of dense matted fibrin deposits in human blood.

  10. Neuroprotective Mechanisms Mediated by CDK5 Inhibition

    PubMed Central

    Mushtaq, Gohar; Greig, Nigel H.; Anwar, Firoz; Al-Abbasi, Fahad A.; Zamzami, Mazin A.; Al-Talhi, Hasan A.; Kamal, Mohammad A.

    2016-01-01

    Cyclin-dependent kinase 5 (CDK5) is a proline-directed serine/threonine kinase belonging to the family of cyclin-dependent kinases. In addition to maintaining the neuronal architecture, CDK5 plays an important role in the regulation of synaptic plasticity, neurotransmitter release, neuron migration and neurite outgrowth. Although various reports have shown links between neurodegeneration and deregulation of cyclin-dependent kinases, the specific role of CDK5 inhibition in causing neuroprotection in cases of neuronal insult or in neurodegenerative diseases is not well-understood. This article discusses current evidence for the involvement of CDK5 deregulation in neurodegenerative disorders and neurodegeneration associated with stroke through various mechanisms. These include upregulation of cyclin D1 and overactivation of CDK5 mediated neuronal cell death pathways, aberrant hyperphosphorylation of human tau proteins and/or neurofilament proteins, formation of neurofibrillary lesions, excitotoxicity, cytoskeletal disruption, motor neuron death (due to abnormally high levels of CDK5/p25) and colchicine-induced apoptosis in cerebellar granule neurons. A better understanding of the role of CDK5 inhibition in neuroprotective mechanisms will help scientists and researchers to develop selective, safe and efficacious pharmacological inhibitors of CDK5 for therapeutic use against human neurodegenerative disorders, such as Alzheimer’s disease, amyotrophic lateral sclerosis and neuronal loss associated with stroke. PMID:26601962

  11. Inhibition of Aflatoxin Production by Surfactants

    PubMed Central

    Rodriguez, Susan B.; Mahoney, Noreen E.

    1994-01-01

    The effect of 12 surfactants on aflatoxin production, growth, and conidial germination by the fungus Aspergillus flavus is reported. Five nonionic surfactants, Triton X-100, Tergitol NP-7, Tergitol NP-10, polyoxyethylene (POE) 10 lauryl ether, and Latron AG-98, reduced aflatoxin production by 96 to 99% at 1% (wt/vol). Colony growth was restricted by the five nonionic surfactants at this concentration. Aflatoxin production was inhibited 31 to 53% by lower concentrations of Triton X-100 (0.001 to 0.0001%) at which colony growth was not affected. Triton X-301, a POE-derived anionic surfactant, had an effect on colony growth and aflatoxin production similar to that of the five POE-derived nonionic surfactants. Sodium dodecyl sulfate (SDS), an anionic surfactant, and dodecyltrimethylammonium bromide, a cationic surfactant, suppressed conidial germination at 1% (wt/vol). SDS had no effect on aflatoxin production or colony growth at 0.001%. The degree of aflatoxin inhibition by a surfactant appears to be a function of the length of the hydrophobic and hydrophilic chains of POE-derived surfactants. Images PMID:16349144

  12. Prostaglandin synthesis inhibition and postprandial intestinal hyperemia.

    PubMed

    Gallavan, R H; Chou, C C

    1982-02-01

    The effect of prostaglandin synthesis inhibition on the postprandial intestinal hyperemia was examined in the jejunum of anesthetized dogs. Both intravenous and intra-arterial infusion of the cyclooxygenase inhibitors indomethacin and mefenamic acid reduced resting jejunal blood flow and markedly enhanced the food-induced jejunal hyperemia. The jejunal vascular response to food did not change after either intravenous or intra-arterial infusion of the carrier solutions or intra-arterial infusion of angiotensin II. The enhancement of the jejunal hyperemia was associated with an increase in the food-induced increase in jejunal oxygen consumption. Infusion of the cyclooxygenase inhibitors increased the mean amplitude of the monophasic intestinal contractions; however, this did not appear to play a role in the enhancement of the food-induced hyperemia. The study indicates that inhibition of prostaglandin synthesis has a marked effect on the postprandial intestinal hyperemia and that this may be due to its enhancement of the jejunal metabolic response to food. The prostaglandins involved and their mechanism of action are unknown.

  13. Kaempferol inhibits thrombosis and platelet activation.

    PubMed

    Choi, Jun-Hui; Park, Se-Eun; Kim, Sung-Jun; Kim, Seung

    2015-08-01

    The objectives of the present study were to investigate whether kaempferol affects pro-coagulant proteinase activity, fibrin clot formation, blood clot and thrombin (or collagen/epinephrine)-stimulated platelet activation, thrombosis, and coagulation in ICR (Imprinting Control Region) mice and SD (Sprague-Dawley) rats. Kaempferol significantly inhibited the enzymatic activities of thrombin and FXa by 68 ± 1.6% and 52 ± 2.4%, respectively. Kaempferol also inhibited fibrin polymer formation in turbidity. Microscopic analysis was performed using a fluorescent conjugate. Kaempferol completely attenuated phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38, c-Jun N-terminal kinase (JNK) 1/2, and phosphoinositide 3-kinase (PI3K)/PKB (AKT) in thrombin-stimulated platelets and delayed aggregation time (clotting) by 34.6% in an assay of collagen/epinephrine-stimulated platelet activation. Moreover, kaempferol protected against thrombosis development in 3 animal models, including collagen/epinephrine- and thrombin-induced acute thromboembolism models and an FeCl3-induced carotid arterial thrombus model. The ex vivo anticoagulant effect of kaempferol was further confirmed in ICR mice. This study demonstrated that kaempferol may be clinically useful due to its ability to reduce or prevent thrombotic challenge.

  14. Dimethyl sulfoxide inhibits NLRP3 inflammasome activation.

    PubMed

    Ahn, Huijeong; Kim, Jeeyoung; Jeung, Eui-Bae; Lee, Geun-Shik

    2014-04-01

    Dimethyl sulfoxide (DMSO) is an amphipathic molecule that is commonly/widely used as a solvent for biological compounds. In addition, DMSO has been studied as a medication for the treatment of inflammation, cystitis, and arthritis. Based on the anti-inflammatory characteristics of DMSO, we elucidated the effects of DMSO on activation of inflammasomes, which are cytoplasmic multi-protein complexes that mediate the maturation of interleukin (IL)-1β by activating caspase-1 (Casp1). In the present study, we prove that DMSO attenuated IL-1β maturation, Casp1 activity, and ASC pyroptosome formation via NLRP3 inflammasome activators. Further, NLRC4 and AIM2 inflammasome activity were not affected, suggesting that DMSO is a selective inhibitor of the NLRP3 inflammasomes. The anti-inflammatory effect of DMSO was further confirmed in animal, LPS-endotoxin sepsis and inflammatory bowel disease models. In addition, DMSO inhibited LPS-mediating IL-1s transcription. Taken together, DMSO shows anti-inflammatory characteristics, attenuates NLRP3 inflammasome activation, and mediates inhibition of IL-1s transcription.

  15. Phenols displaying tyrosinase inhibition from Humulus lupulus.

    PubMed

    Kim, Dae Wook; Woo, Hyun Sim; Kim, Jeong Yoon; Ryuk, Jin Ah; Park, Ki Hun; Ko, Byoung Seob

    2016-10-01

    Tyrosinase is the rate-limiting enzyme for the production of melanin and other pigments via the oxidation of l-tyrosine. The methanol extract from Humulus lupulus showed potent inhibition against mushroom tyrosinase. The bioactivity-guided fractionation of this methanol extract resulted in the isolation of seven flavonoids (1-7), identified as xanthohumol (1), 4'-O-methylxanthohumol (2), xanthohumol C (3), flavokawain C (4), xanthoumol B (5), 6-prenylnaringenin (6) and isoxanthohumol (7). All isolated flavonoids (1-7) effectively inhibited the monophenolase (IC50s = 15.4-58.4 µM) and diphenolase (IC50s = 27.1-117.4 µM) activities of tyrosinase. Kinetic studies using Lineweaver-Burk and Dixon-plots revealed that chalcones (1-5) were competitive inhibitors, whereas flavanones (6 and 7) exhibited both mixed and non-competitive inhibitory characteristics. In conclusion, this study is the first to demonstrate that the phenolic phytochemicals of H. lupulus display potent inhibitory activities against tyrosinase.

  16. Infection of Human Fallopian Tube Epithelial Cells with Neisseria gonorrhoeae Protects Cells from Tumor Necrosis Factor Alpha-Induced Apoptosis

    PubMed Central

    Morales, Priscilla; Reyes, Paz; Vargas, Macarena; Rios, Miguel; Imarai, Mónica; Cardenas, Hugo; Croxatto, Horacio; Orihuela, Pedro; Vargas, Renato; Fuhrer, Juan; Heckels, John E.; Christodoulides, Myron; Velasquez, Luis

    2006-01-01

    Following infection with Neisseria gonorrhoeae, bacteria may ascend into the Fallopian tubes (FT) and induce salpingitis, a major cause of infertility. In the FT, interactions between mucosal epithelial cells and gonococci are pivotal events in the pathogen's infection cycle and the inflammatory response. In the current study, primary FT epithelial cells were infected in vitro with different multiplicities of infection (MOI) of Pil+ Opa+ gonococci. Bacteria showed a dose-dependent association with cells and induced the secretion of tumor necrosis factor alpha (TNF-α). A significant finding was that gonococcal infection (MOI = 1) induced apoptosis in approximately 30% of cells, whereas increasing numbers of bacteria (MOI = 10 to 100) did not induce apoptosis. Apoptosis was observed in only 11% of cells with associated bacteria, whereas >84% of cells with no adherent bacteria were apoptotic. TNF-α was a key contributor to apoptosis, since (i) culture supernatants from cells infected with gonococci (MOI = 1) induced apoptosis in naïve cultures, suggesting that a soluble factor was responsible; (ii) gonococcal infection-induced apoptosis was inhibited with anti-TNF-α antibodies; and (iii) the addition of exogenous TNF-α induced apoptosis, which was inhibited by the presence of increasing numbers of bacteria (MOI = 10 to 100). These data suggest that TNF-α-mediated apoptosis of FT epithelial cells is likely a primary host defense mechanism to prevent pathogen colonization. However, epithelial cell-associated gonococci have evolved a mechanism to protect the cells from undergoing TNF-α-mediated apoptosis, and this modulation of the host innate response may contribute to establishment of infection. Understanding the antiapoptotic mechanisms used by Neisseria gonorrhoeae will inform the pathogenesis of salpingitis and could suggest new intervention strategies for prevention and treatment of the disease. PMID:16714596

  17. 3-Bromopyruvate inhibits human gastric cancer tumor growth in nude mice via the inhibition of glycolysis.

    PubMed

    Xian, Shu-Lin; Cao, Wei; Zhang, Xiao-Dong; Lu, Yun-Fei

    2015-02-01

    Tumor cells primarily depend upon glycolysis in order to gain energy. Therefore, the inhibition of glycolysis may inhibit tumor growth. Our previous study demonstrated that 3-bromopyruvate (3-BrPA) inhibited gastric cancer cell proliferation in vitro. However, the ability of 3-BrPA to suppress tumor growth in vivo, and its underlying mechanism, have yet to be elucidated. The aim of the present study was to investigate the inhibitory effect of 3-BrPA in an animal model of gastric cancer. It was identified that 3-BrPA exhibited strong inhibitory effects upon xenograft tumor growth in nude mice. In addition, the antitumor function of 3-BrPA exhibited a dose-effect association, which was similar to that of the chemotherapeutic agent, 5-fluorouracil. Furthermore, 3-BrPA exhibited low toxicity in the blood, liver and kidneys of the nude mice. The present study hypothesized that the inhibitory effect of 3-BrPA is achieved through the inhibition of hexokinase activity, which leads to the downregulation of B-cell lymphoma 2 (Bcl-2) expression, the upregulation of Bcl-2-associated X protein expression and the subsequent activation of caspase-3. These data suggest that 3-BrPA may be a novel therapy for the treatment of gastric cancer.

  18. Distinct Neural Correlates for Two Types of Inhibition in Bilinguals: Response Inhibition versus Interference Suppression

    ERIC Educational Resources Information Center

    Luk, Gigi; Anderson, John A. E.; Craik, Fergus I. M.; Grady, Cheryl; Bialystok, Ellen

    2010-01-01

    To examine the effects of bilingualism on cognitive control, we studied monolingual and bilingual young adults performing a flanker task with functional MRI. The trial types of primary interest for this report were incongruent and no-go trials, representing interference suppression and response inhibition, respectively. Response times were similar…

  19. Glyphosate and AMPA inhibit cancer cell growth through inhibiting intracellular glycine synthesis.

    PubMed

    Li, Qingli; Lambrechts, Mark J; Zhang, Qiuyang; Liu, Sen; Ge, Dongxia; Yin, Rutie; Xi, Mingrong; You, Zongbing

    2013-01-01

    Glycine is a nonessential amino acid that is reversibly converted from serine intracellularly by serine hydroxymethyltransferase. Glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), are analogs to glycine, thus they may inhibit serine hydroxymethyltransferase to decrease intracellular glycine synthesis. In this study, we found that glyphosate and AMPA inhibited cell growth in eight human cancer cell lines but not in two immortalized human normal prostatic epithelial cell lines. AMPA arrested C4-2B and PC-3 cancer cells in the G1/G0 phase and inhibited entry into the S phase of the cell cycle. AMPA also promoted apoptosis in C4-2B and PC-3 cancer cell lines. AMPA upregulated p53 and p21 protein levels as well as procaspase 9 protein levels in C4-2B cells, whereas it downregulated cyclin D3 protein levels. AMPA also activated caspase 3 and induced cleavage of poly (adenosine diphosphate [ADP]-ribose) polymerase. This study provides the first evidence that glyphosate and AMPA can inhibit proliferation and promote apoptosis of cancer cells but not normal cells, suggesting that they have potentials to be developed into a new anticancer therapy.

  20. Triple ACE-ECE-NEP inhibition in heart failure: a comparison with ACE and dual ECE-NEP inhibition.

    PubMed

    Mellin, Virginie; Jeng, Arco Y; Monteil, Christelle; Renet, Sylvanie; Henry, Jean Paul; Thuillez, Christian; Mulder, Paul

    2005-09-01

    Mortality remains high in chronic heart failure (CHF) because under ACE inhibitor treatment other neurohumoral systems remain/become (de)activated, such as the endothelin and atrial natriuretic peptide pathways. Dual endothelin-converting enzyme-neutral endopeptidase (ECE-NEP) inhibition exerts beneficial effects in experimental CHF, but whether "triple" ACE-ECE-NEP inhibition is superior to ACE or ECE-NEP inhibition is unknown. We compared, in rats with CHF, ACE-ECE-NEP to ACE or ECE-NEP inhibition in terms of left ventricular (LV) hemodynamics and remodeling. Benazepril (2 mg/kg/d) or the ECE-NEP inhibitor CGS26303 (10 mg/kg/d) were administered alone or in combination (subcutaneously for 28 days starting 7 days after coronary ligation). ACE-ECE-NEP inhibition reduced blood pressure more markedly than ACE or ECE-NEP inhibition. All treatments increased cardiac output to the same extent, but ACE-ECE-NEP inhibition reduced LV diameter and LV end-diastolic pressure more markedly than ACE or ECE-NEP inhibition. The reduction of LV weight and collagen accumulation in the "viable" myocardium was most pronounced after ACE-ECE-NEP inhibition. These results, obtained in experimental CHF, illustrate a further improvement of LV hemodynamics and structure after ACE-ECE-NEP inhibition compared with either ACE or ECE-NEP inhibition, but whether this is associated with a further improvement of exercise tolerance and/or survival remains to be determined.

  1. Equol inhibits growth, induces atresia, and inhibits steroidogenesis of mouse antral follicles in vitro

    PubMed Central

    Mahalingam, Sharada; Gao, Liying; Gonnering, Marni; Helferich, William; Flaws, Jodi A.

    2016-01-01

    Equol is a non-steroidal estrogen metabolite produced by microbial conversion of daidzein, a major soy isoflavone, in the gut of some humans and many animal species. Isoflavones and their metabolites can affect endogenous estradiol production, action, and metabolism, potentially influencing ovarian follicle function. However, no studies have examined the effects of equol on intact ovarian antral follicles, which are responsible for sex steroid synthesis and further development into ovulatory follicles. Thus, the present study tested the hypothesis that equol inhibits antral follicle growth, increases follicle atresia, and inhibits steroidogenesis in the adult mouse ovary. To test this hypothesis, antral follicles isolated from adult CD-1 mice were cultured with vehicle control (dimethyl sulfoxide; DMSO) or equol (600 nM, 6 μM, 36 μM, 100 μM) for 48 and 96 h. Every 24 h, follicle diameters were measured to monitor growth. At 48 and 96 h, the culture medium was subjected to measurement of hormone levels, and the cultured follicles were subjected to gene expression analysis. Additionally, follicles were histologically evaluated for signs of atresia after 96 h of culture. The results indicate that equol (100 μM) inhibited follicle growth, altered the mRNA levels of bcl2-associated X protein and B cell leukemia/lymphoma 2, and induced follicle atresia. Further, equol decreased the levels of estradiol, testosterone, androstenedione, and progesterone, and it decreased mRNA levels of cholesterol side-chain cleavage, steroid 17-α-hydroxalase, and aromatase. Collectively, these data indicate that equol inhibits growth, increases atresia, and inhibits steroidogenesis of cultured mouse antral follicles. PMID:26876617

  2. Doxycycline inhibits leukemic cell migration via inhibition of matrix metalloproteinases and phosphorylation of focal adhesion kinase.

    PubMed

    Wang, Chunhuai; Xiang, Ru; Zhang, Xiangzhong; Chen, Yunxian

    2015-09-01

    Doxycycline, a tetracycline-based antibiotic, has been reported to attenuate melanoma cell migration through inhibiting the focal adhesion kinase (FAK) signaling pathway. However, it remains to be elucidated whether doxycycline exerts this effect on leukemia cell migration. The present study aimed to examine the role of doxycycline in leukemia cell migration. The invasion capacities of the human leukemia cell lines KG1a (acute myelogenous leukemia) and K562 (chronic myelogenous leukemia) were evaluated using Matrigel® matrix‑coated Transwell® chamber assays; leukemic cell lines treated with doxycycline (1 µg/ml) or anti‑β1‑integrin antibodies were added to the upper chamber, while untreated cells were included as controls. Reverse transcription quantitative polymerase chain reaction was performed in order to further understand the influence of doxycycline treatment on the expression of FAK and gelatinases in the KG1a and K562 leukemic cell lines. In addition, FAK protein expression and phosphorylation were determined using western blot analysis in order to investigate the mechanism by which doxycycline inhibited leukemic cell migration. The results revealed that doxycycline treatment significantly attenuated the migration of KG1a and K562 cells, which was demonstrated to be associated with inhibition of the expression and phosphorylation of FAK. In addition, doxycycline treatment inhibited matrix metalloproteinase (MMP)‑2 and MMP‑9 expression. Furthermore, incubation with blocking anti‑β1‑integrin antibodies had an analogous inhibitory effect on leukemic cell migration to that of doxycycline. In conclusion, the results of the present study suggested that doxycycline attenuated leukemic cell migration through inhibiting the FAK signaling pathway. Therefore, doxycycline may have potential for use as a novel strategy for the treatment of leukemia.

  3. Neural and behavioral mechanisms of proactive and reactive inhibition.

    PubMed

    Meyer, Heidi C; Bucci, David J

    2016-10-01

    Response inhibition is an important component of adaptive behavior. Substantial prior research has focused on reactive inhibition, which refers to the cessation of a motor response that is already in progress. More recently, a growing number of studies have begun to examine mechanisms underlying proactive inhibition, whereby preparatory processes result in a response being withheld before it is initiated. It has become apparent that proactive inhibition is an essential component of the overall ability to regulate behavior and has implications for the success of reactive inhibition. Moreover, successful inhibition relies on learning the meaning of specific environmental cues that signal when a behavioral response should be withheld. Proactive inhibitory control is mediated by stopping goals, which reflect the desired outcome of inhibition and include information about how and when inhibition should be implemented. However, little is known about the circuits and cellular processes that encode and represent features in the environment that indicate the necessity for proactive inhibition or how these representations are implemented in response inhibition. In this article, we will review the brain circuits and systems involved in implementing inhibitory control through both reactive and proactive mechanisms. We also comment on possible cellular mechanisms that may contribute to inhibitory control processes, noting that substantial further research is necessary in this regard. Furthermore, we will outline a number of ways in which the temporal dynamics underlying the generation of the proactive inhibitory signal may be particularly important for parsing out the neurobiological correlates that contribute to the learning processes underlying various aspects of inhibitory control.

  4. Comparison of Alcohol Impairment of Behavioral and Attentional Inhibition

    PubMed Central

    Weafer, Jessica; Fillmore, Mark T.

    2012-01-01

    Background Despite the wealth of studies demonstrating the impairing effects of alcohol on behavioral inhibition, less is known regarding effects of the drug on attentional inhibition (i.e., the ability to ignore distracting stimuli in the environment in order to focus attention on relevant information). The current study examined alcohol impairment of both behavioral and attentional inhibition, as well as potential associations between the two mechanisms of inhibitory control. Methods Men (n = 27) and women (n = 21) performed a measure of behavioral inhibition (cued go/no-go task) and a measure of attentional inhibition (delayed ocular return task) following three doses of alcohol: 0.65 g/kg, 0.45 g/kg, and 0.0 g/kg (placebo). Results Alcohol impaired both behavioral and attentional inhibition relative to placebo; however, correlational analyses revealed no associations between measures of behavioral and attentional inhibition following any dose. Additionally, men committed more inhibitory failures on the behavioral inhibition task, whereas women committed more inhibitory failures on the attentional inhibition task. Conclusions These findings suggest that behavioral and attentional inhibition are equally sensitive to the impairing effects of alcohol, yet represent distinct components of inhibitory control. Additionally, the observed gender differences in control of behavior and attention could have important implications regarding negative consequences associated with alcohol-induced disinhibition in men and women. PMID:22673197

  5. Auxin inhibition of ripening in bartlett pears.

    PubMed

    Frenkel, C; Dyck, R

    1973-01-01

    The effect of indoleacetic acid and 2,4-dichlorophenoxyacetic acid on the ripening of intact mature-green pears (Pyrus communis var. Bartlett) was investigated using a vacuum infiltration technique.The effects of indoleacetic acid and 2,4-dichlorophenoxyacetic acid at concentrations of 0.01, 0.1, and 1.0 mm each were studied on softening, degreening, and on ethylene and CO(2) evolution. Softening and degreening were inhibited increasingly in response to increased concentrations of indoleacetic acid. This inhibitory property was amplified by 2,4-dichlorophenoxyacetic acid at concentrations comparable to those of indoleacetic acid. Application of the auxins also prevented the climacteric rise in respiration, but stimulated ethylene synthesis. Despite the presence of elevated ethylene levels, the inhibitory auxin effect was predominant.It is proposed that endogenous auxins in fruit represent a resistance factor in ripening and must be inactivated before ripening can occur.

  6. ACAT inhibition and amyloid beta reduction.

    PubMed

    Bhattacharyya, Raja; Kovacs, Dora M

    2010-08-01

    Alzheimer's disease (AD) is a devastating neurodegenerative disorder. Accumulation and deposition of the beta-amyloid (Abeta) peptide generated from its larger amyloid precursor protein (APP) is one of the pathophysiological hallmarks of AD. Intracellular cholesterol was shown to regulate Abeta production. Recent genetic and biochemical studies indicate that not only the amount, but also the distribution of intracellular cholesterol is critical to regulate Abeta generation. Acyl-coenzyme A: cholesterol acyl-transferase (ACAT) is a family of enzymes that regulates the cellular distribution of cholesterol by converting membrane cholesterol into hydrophobic cholesteryl esters for cholesterol storage and transport. Using pharmacological inhibitors and transgenic animal models, we and others have identified ACAT1 as a potential therapeutic target to lower Abeta generation and accumulation. Here we discuss data focusing on ACAT inhibition as an effective strategy for the prevention and treatment of AD.

  7. Inhibition of cyclodextrins on α-galactosidase.

    PubMed

    Yao, Di; Zhu, Zhenzhou; Cai, Hongyan; Chen, Xuan; Sun, Wei; Barba, Francisco J; Li, Fang; Shen, Wangyang; Ding, Wenping

    2017-02-15

    This work successfully investigated the effects of different influential factors and hydrophobic cavities of cyclodextrins (CDs) on α-galactosidase (α-Gal) by detecting α-Gal activity. The highest inhibitory concentration of three kinds of CDs (α-, β-, and γ-CD) on α-Gal was 10mM. Moreover, the highest inhibition of α-Gal was obtained under the following conditions: reaction time of 90min, temperature of 30°C, and pH 6.0. Compared with other CDs, β-CD showed more ability to interact with α-Gal due to its appropriate cavity geometric dimensions. From circular dichroism and nuclear magnetic resonance it was observed that β-CD changed the secondary structure of α-Gal and formed a hydrogen bond with this enzyme.

  8. Inhibition of bleach-induced luminol chemiluminescence.

    PubMed

    Kent, Erina J M; Elliot, Douglas A; Miskelly, Gordon M

    2003-01-01

    The luminol chemiluminescence presumptive test for blood is based on the mild peroxidase activity of hemoglobin in basic peroxide solution. However, this test is subject to interference by strong oxidants, certain transition metal ions, and true peroxidases. This paper reports methods for reducing the interference caused by hypochlorite-containing bleaches. Amines such as 1,2-diaminoethane react rapidly with hypochlorite without interfering significantly with the hemoglobin-catalyzed oxidation. Thus, addition of 0.1 mol/L 1,2-diaminoethane to a standard luminol-peroxide spray lead to almost complete inhibition of hypochlorite-induced chemiluminescence while satisfactory chemiluminescence was still observed from bloodstains. If time allows, an alternative method for reducing interference from hypochlorite bleach is to wait several days until the bloodstains have dried thoroughly, by which time the hypochlorite will have decomposed.

  9. Tooth brushing inhibits oral bacteria in dogs

    PubMed Central

    WATANABE, Kazuhiro; HAYASHI, Kotaro; KIJIMA, Saku; NONAKA, Chie; YAMAZOE, Kazuaki

    2015-01-01

    In this study, scaling, polishing and daily tooth brushing were performed in 20 beagle dogs, and the number of oral bacteria was determined using a bacterial counter. The dogs were randomized into the scaling (S), scaling + polishing (SP), scaling + tooth daily brushing (SB) and scaling + polishing + tooth daily brushing (SPB) groups. Samples were collected from the buccal surface of the maxillary fourth premolars of the dogs immediately after scaling and every week thereafter from weeks 1 to 8. Throughout the study, the number of bacteria was significantly lower in the SB and SPB groups compared with the S group. The findings suggest that daily tooth brushing inhibited oral bacterial growth in the dogs. PMID:25994486

  10. Inhibition of return: Twenty years after.

    PubMed

    Lupianez, Juan; Klein, Raymond M; Bartolomeo, Paolo

    2006-10-01

    When responding to a suddenly appearing stimulus, we are slower and/or less accurate when the stimulus occurs at the same location of a previous event than when it appears in a new location. This phenomenon, often referred to as inhibition of return (IOR), has fostered a huge amount of research in the last 20 years. In this selective review, which introduces a Special Issue of Cognitive Neuropsychology dedicated to IOR, we discuss some of the methods used for eliciting IOR and its boundary conditions. We also address its debated relationships with orienting of attention, succinctly review findings of altered IOR in normal elderly and neuropsychiatric patients, and present results concerning its possible neural bases. We conclude with an outline of the papers collected in this issue, which offer a more in-depth treatment of behavioural, neural, and theoretical issues related to IOR.

  11. Identification of enteroviruses by hemagglutination-inhibition.

    PubMed

    Kern, J; Rosen, L

    1966-05-01

    Kern, Jerome (Pacific Research Section, Honolulu, Hawaii), and Leon Rosen. Identification of enteroviruses by hemagglutination-inhibition. J. Bacteriol. 91:1936-1942. 1966.-Approximately 40% of a group of 906 enterovirus isolates cytopathic for monkey cell cultures were found to possess hemagglutinins for human erythrocytes when tested at temperatures of 4 and 37 C and at pH 5.8 and 7.3. The hemagglutinating isolates could be classified by relatively simple techniques into 18 serotypes. Four of these serotypes, echovirus type 24 and coxsackievirus B types 1, 5, and 6, had not previously been known to include hemagglutinating strains. One serotype, Toluca-3, represented a previously unrecognized enterovirus, and two other serotypes may also represent previously unrecognized enteroviruses.

  12. Tailoring elastase inhibition with synthetic peptides.

    PubMed

    Vasconcelos, Andreia; Azoia, Nuno G; Carvalho, Ana C; Gomes, Andreia C; Güebitz, Georg; Cavaco-Paulo, Artur

    2011-09-01

    Chronic wounds are the result of excessive amounts of tissue destructive proteases such as human neutrophil elastase (HNE). The high levels of this enzyme found on those types of wounds inactivate the endogenous inhibitor barrier thus, the search for new HNE inhibitors is required. This work presents two new HNE inhibitor peptides, which were synthesized based on the reactive-site loop of the Bowman-Birk inhibitor protein. The results obtained indicated that these new peptides are competitive inhibitors for HNE and, the inhibitory activity can be modulated by modifications introduced at the N- and C-terminal of the peptides. Furthermore, these peptides were also able to inhibit elastase from a human wound exudate while showing no cytotoxicity against human skin fibroblasts in vitro, greatly supporting their potential application in chronic wound treatment.

  13. Selective Raf Inhibition in Cancer Therapy

    PubMed Central

    Khazak, Vladimir; Astsaturov, Igor; Serebriiskii, Ilya G; Golemis, Erica A

    2009-01-01

    Over the past 5 years, the Raf kinase family has emerged as a promising target for protein-directed cancer therapy development. The goal of this review is to first provide a concise summary of the data validating Raf proteins as high-interest therapeutic targets. We then outline the mode of action of Raf kinases, emphasizing how Raf activities and protein interactions suggest specific approaches to inhibiting Raf. We then summarize the set of drugs, antisense reagents, and antibodies available or in development for therapeutically targeting Raf or Raf-related proteins, as well as current strategies combining these and other therapeutic agents. Finally, we discuss recent results from systems biology analyses that have the potential to increasingly guide the intelligent selection of combination therapies involving Raf-targeting agents and other therapeutics. PMID:18020980

  14. Selective Raf inhibition in cancer therapy.

    PubMed

    Khazak, Vladimir; Astsaturov, Igor; Serebriiskii, Ilya G; Golemis, Erica A

    2007-12-01

    Over the past 5 years, the Raf kinase family has emerged as a promising target for protein-directed cancer therapy development. The goal of this review is to first provide a concise summary of the data validating Raf proteins as high-interest therapeutic targets. The authors then outline the mode of action of Raf kinases, emphasizing how Raf activities and protein interactions suggest specific approaches to inhibiting Raf. The authors then summarize the set of drugs, antisense reagents and antibodies available or in development for therapeutically targeting Raf or Raf-related proteins, as well as existing strategies combining these and other therapeutic agents. Finally, the authors discuss recent results from systems biology analyses that have the potential to increasingly guide the intelligent selection of combination therapies involving Raf-targeting agents and other therapeutics.

  15. Inhibition of human papillomavirus expression using DNAzymes.

    PubMed

    Benítez-Hess, María Luisa; Reyes-Gutiérrez, Pablo; Alvarez-Salas, Luis Marat

    2011-01-01

    Deoxyribozymes (DXZs) are catalytic oligodeoxynucleotides capable of performing diverse functions including the specific cleavage of a target RNA. These molecules represent a new type of therapeutic oligonucleotides combining the efficiency of ribozymes and the intracellular endurance and simplicity of modified antisense oligonucleotides. Commonly used DXZs include the 8-17 and 10-23 motifs, which have been engineered to destroy disease-associated genes with remarkable efficiency. Targeting DXZs to disease-associated transcripts requires extensive biochemical testing to establish target RNA accessibility, catalytic efficiency, and nuclease sensibility. The usage of modified nucleotides to render nuclease-resistance DXZs must be counterweighted against deleterious consequences on catalytic activity. Further intracellular testing is required to establish the effect of microenvironmental conditions on DXZ activity and off-target issues. Application of modified DXZs to cervical cancer results in specific growth inhibition, cell death, and apoptosis. Thus, DXZs represent a highly effective antisense moiety with minimal secondary effects.

  16. Allosteric inhibition of HIV-1 integrase activity

    PubMed Central

    Engelman, Alan; Kessl, Jacques J.; Kvaratskhelia, Mamuka

    2013-01-01

    HIV-1 integrase is an important therapeutic target in the fight against HIV/AIDS. Integrase strand transfer inhibitors (INSTIs), which target the enzyme active site, have witnessed clinical success over the past 5 years, but the generation of drug resistance poses challenges to INSTI-based therapies moving forward. Integrase is a dynamic protein, and its ordered multimerization is critical to enzyme activity. The integrase tetramer, bound to viral DNA, interacts with host LEDGF/p75 protein to tether integration to active genes. Allosteric integrase inhibitors (ALLINIs) that compete with LEDGF/p75 for binding to integrase disrupt integrase assembly with viral DNA and allosterically inhibit enzyme function. ALLINIs display steep dose response curves and synergize with INSTIs ex vivo, highlighting this novel inhibitor class for clinical development. PMID:23647983

  17. Novel Polyanions Inhibiting Replication of Influenza Viruses

    PubMed Central

    Ciejka, Justyna; Milewska, Aleksandra; Wytrwal, Magdalena; Wojarski, Jacek; Golda, Anna; Ochman, Marek; Nowakowska, Maria

    2016-01-01

    Novel sulfonated derivatives of poly(allylamine hydrochloride) (NSPAHs) and N-sulfonated chitosan (NSCH) have been synthesized, and their activity against influenza A and B viruses has been studied and compared with that of a series of carrageenans, marine polysaccharides of well-documented anti-influenza activity. NSPAHs were found to be nontoxic and very soluble in water, in contrast to gel-forming and thus generally poorly soluble carrageenans. In vitro and ex vivo studies using susceptible cells (Madin-Darby canine kidney epithelial cells and fully differentiated human airway epithelial cultures) demonstrated the antiviral effectiveness of NSPAHs. The activity of NSPAHs was proportional to the molecular mass of the chain and the degree of substitution of amino groups with sulfonate groups. Mechanistic studies showed that the NSPAHs and carrageenans inhibit influenza A and B virus assembly in the cell. PMID:26729490

  18. Selecting patients for KIT inhibition in melanoma.

    PubMed

    Carvajal, Richard D; Hamid, Omid; Antonescu, Cristina R

    2014-01-01

    For many years, melanoma has been regarded as a single disease in terms of therapeutic considerations. The more recent identification of multiple molecular mechanisms underlying the development, progression, and prognosis of melanoma has led to a new paradigm for the management of this disease, has created new therapeutic opportunities, and has led to improved clinical outcomes. Such advances, however, are dependent upon methods that can reproducibly identify key molecular alterations within an individual tumor, define clinically relevant genetic subgroups of disease, and permit improved patient selection for targeted therapies.Melanomas harboring genetic alterations of KIT have been demonstrated to constitute one such molecular subgroup of disease. In this chapter, we will discuss the biology of KIT in melanoma, review the rationale for and clinical data regarding KIT inhibition in melanomas harboring activating alterations of KIT, propose guidelines for the selection of patients for KIT inhibitor therapy, and, finally, present laboratory methods for KIT assessment in melanoma.

  19. Inhibition and Mechanism of HDAC8 Revisited

    PubMed Central

    2015-01-01

    Histone deacetylases (HDACs) have found intense interest as drug targets for a variety of diseases, but there is disagreement about basic aspects of the inhibition and mechanism of HDACs. QM/MM calculations of HDAC8 including a large QM region provide a model that is consistent with the available crystal structures and structure–activity relationships of different HDAC inhibitors. The calculations support a spontaneous proton transfer from a hydroxamic acid to an active site histidine upon binding to the zinc. The role of the H142/D176 catalytic dyad as the general base of the reaction is elucidated. The reasons for the disagreements between previous proposals are discussed. The results provide detailed insights into the unique mechanism of HDACs, including the role of the two catalytic dyads and function of the potassium near the active site. They also have important implications for the design of novel inhibitors for a number of HDACs such as the class IIa HDACs. PMID:25060069

  20. Structural basis of kynurenine 3-monooxygenase inhibition

    PubMed Central

    Amaral, Marta; Levy, Colin; Heyes, Derren J.; Lafite, Pierre; Outeiro, Tiago F.; Giorgini, Flaviano; Leys, David; Scrutton, Nigel S.

    2013-01-01

    Inhibition of kynurenine 3-monooxygenase (KMO), an enzyme in the eukaryotic tryptophan catabolic pathway (i.e. kynurenine pathway), leads to amelioration of Huntington’s disease-relevant phenotypes in yeast, fruit fly, and mouse models1–5, as well as a mouse model of Alzheimer’s disease3. KMO is a FAD-dependent monooxygenase, and is located in the outer mitochondrial membrane where it converts L-kynurenine to 3-hydroxykynurenine. Perturbations in the levels of kynurenine pathway metabolites have been linked to the pathogenesis of a spectrum of brain disorders6, as well as cancer7,8, and several peripheral inflammatory conditions9. Despite the importance of KMO as a target for neurodegenerative disease, the molecular basis of KMO inhibition by available lead compounds has remained hitherto unknown. Here we report the first crystal structure of KMO, in the free form and in complex with the tight-binding inhibitor UPF 648. UPF 648 binds close to the FAD cofactor and perturbs the local active site structure, preventing productive binding of the substrate kynurenine. Functional assays and targeted mutagenesis revealed that the active site architecture and UPF 648 binding are essentially identical in human KMO, validating the yeast KMO:UPF 648 structure as a template for structure-based drug design. This will inform the search for new KMO inhibitors that are able to cross the blood-brain barrier in targeted therapies against neurodegenerative diseases such as Huntington’s, Alzheimer’s, and Parkinson’s diseases. PMID:23575632

  1. Inhibition of morphine metabolism by ketamine.

    PubMed

    Qi, Xiaoxin; Evans, Allan M; Wang, Jiping; Miners, John O; Upton, Richard N; Milne, Robert W

    2010-05-01

    Clinical observation of a synergistic effect of ketamine on morphine analgesia remains controversial. Although a pharmacodynamic basis for an interaction has been explored in animal and clinical studies, the possibility of a pharmacokinetic mechanism has not been investigated. Whereas both morphine and morphine-6-glucuronide are effective analgesics, morphine-3-glucuronide (M3G) lacks activity. Thus, changes in the metabolism and disposition of morphine may result in an altered response. First, we investigated the interaction between morphine and ketamine in the isolated perfused rat liver preparation. The clearance of morphine was decreased from 16.8 +/- 4.6 ml/min in the control period to 7.7 +/- 2.8 ml/min in the ketamine-treatment period, with the formation clearance of M3G decreasing from 8.0 +/- 4.1 ml/min to 2.1 +/- 1.1 ml/min. Fractional conversion of morphine to M3G was significantly decreased from 0.46 +/- 0.17 in the control period to 0.28 +/- 0.14 upon the addition of ketamine. The possible mechanism of the interaction was further investigated in vitro with rat liver microsomes as the enzyme source. The formation of M3G followed single-enzyme Michaelis-Menten kinetics, with a mean apparent K(m) of 2.18 +/- 0.45 mM and V(max) of 8.67 +/- 0.59 nmol/min/mg. Ketamine inhibited morphine 3-glucuronidation noncompetitively, with a mean K(i) value of 33.3 +/- 7.9 microM. The results demonstrate that ketamine inhibits the glucuronidation of morphine in a rat model.

  2. Protein Fibrillation Lag Times During Kinetic Inhibition

    PubMed Central

    Pagano, Rodrigo S.; López Medus, Máximo; Gómez, Gabriela E.; Couto, Paula M.; Labanda, María S.; Landolfo, Lucas; D’Alessio, Cecilia; Caramelo, Julio J.

    2014-01-01

    Protein aggregation is linked to more than 30 human pathologies, including Alzheimer’s and Parkinson’s diseases. Since small oligomers that form at the beginning of the fibrillation process probably are the most toxic elements, therapeutic strategies involving fibril fragmentation could be detrimental. An alternative approach, named kinetic inhibition, aims to prevent fibril formation by using small ligands that stabilize the parent protein. The factors that govern fibrillation lag times during kinetic inhibition are largely unknown, notwithstanding their importance for designing effective long-term therapies. Inhibitor-bound species are not likely to be incorporated into the core of mature fibrils, although their presence could alter the kinetics of the fibrillation process. For instance, inhibitor-bound species may act as capping elements that impair the nucleation process and/or fibril growth. Here, we address this issue by studying the effect of two natural inhibitors on the fibrillation behavior of lysozyme at neutral pH. We analyzed a set of 79 fibrillation curves obtained in lysozyme alone and a set of 37 obtained in the presence of inhibitors. We calculated the concentrations of the relevant species at the beginning of the curves using the inhibitor-binding constants measured under the same experimental conditions. We found that inhibitor-bound protein species do not affect fibrillation onset times, which are mainly determined by the concentration of unbound protein species present in equilibrium. In this system, knowledge of the fibrillation kinetics and inhibitor affinities suffices to predict the effect of kinetic inhibitors on fibrillation lag times. In addition, we developed a new methodology to better estimate fibrillation lag times from experimental curves. PMID:25099810

  3. Inhibition of Quorum Sensing in Staphylococcus spp.

    PubMed

    Brackman, Gilles; Coenye, Tom

    2015-01-01

    The Gram-positive, facultative anaerobic coccus-shaped bacteria of the genus Staphylococcus are among the most important causative agents of acute and chronic bacterial infections in humans as well as in animals. Treatment of Staphylococcus infections has become increasingly challenging due to the growing problem of antibiotic resistance. For this reason innovative antimicrobials with novel targets and modes of action are needed. Since the discovery that QS is used by Staphylococcus spp. to coordinate the expression of several genes involved in virulence, biofilm formation and pathogenicity, QS inhibition has gained increasing attention as an alternative anti-pathogenic strategy. A major advantage compared with antibiotic therapy is that QSIs are used in concentrations that do not affect bacterial growth. For this reason, it is expected that these compounds would exert less pressure towards the development of resistance. However, some important points still need to be addressed. Although several inhibitors have proven to be active antipathogenic agents in vitro and in several in vivo models, it is still unknown whether these compounds will also be useful in humans. Furthermore, several fundamental mechanisms by which the different QS systems in Staphylococcus spp. exert their regulatory functions and how they are inhibited by QSIs are still poorly understood. In order to achieve real-life applications with QSIs, these challenges should be addressed and more research will be needed. In this article, we will discuss the different QS systems present in Staphylococcus spp., how they are used to control virulence and biofilm formation and how they can be blocked.

  4. Nitric oxide synthases: structure, function and inhibition.

    PubMed Central

    Alderton, W K; Cooper, C E; Knowles, R G

    2001-01-01

    This review concentrates on advances in nitric oxide synthase (NOS) structure, function and inhibition made in the last seven years, during which time substantial advances have been made in our understanding of this enzyme family. There is now information on the enzyme structure at all levels from primary (amino acid sequence) to quaternary (dimerization, association with other proteins) structure. The crystal structures of the oxygenase domains of inducible NOS (iNOS) and vascular endothelial NOS (eNOS) allow us to interpret other information in the context of this important part of the enzyme, with its binding sites for iron protoporphyrin IX (haem), biopterin, L-arginine, and the many inhibitors which interact with them. The exact nature of the NOS reaction, its mechanism and its products continue to be sources of controversy. The role of the biopterin cofactor is now becoming clearer, with emerging data implicating one-electron redox cycling as well as the multiple allosteric effects on enzyme activity. Regulation of the NOSs has been described at all levels from gene transcription to covalent modification and allosteric regulation of the enzyme itself. A wide range of NOS inhibitors have been discussed, interacting with the enzyme in diverse ways in terms of site and mechanism of inhibition, time-dependence and selectivity for individual isoforms, although there are many pitfalls and misunderstandings of these aspects. Highly selective inhibitors of iNOS versus eNOS and neuronal NOS have been identified and some of these have potential in the treatment of a range of inflammatory and other conditions in which iNOS has been implicated. PMID:11463332

  5. Milk inhibits the biological activity of ricin.

    PubMed

    Rasooly, Reuven; He, Xiaohua; Friedman, Mendel

    2012-08-10

    Ricin is a highly toxic protein produced by the castor plant Ricinus communis. The toxin is relatively easy to isolate and can be used as a biological weapon. There is great interest in identifying effective inhibitors for ricin. In this study, we demonstrated by three independent assays that a component of reconstituted powdered milk has a high binding affinity to ricin. We discovered that milk can competitively bind to and reduce the amount of toxin available to asialofetuin type II, which is used as a model to study the binding of ricin to galactose cell-surface receptors. Milk also removes ricin bound to the microtiter plate. In parallel experiments, we demonstrated by activity assay and by immuno-PCR that milk can bind competitively to 1 ng/ml ricin, reducing the amount of toxin uptake by the cells, and thus inhibit the biological activity of ricin. The inhibitory effect of milk on ricin activity in Vero cells was at the same level as by anti-ricin antibodies. We also found that (a) milk did not inhibit ricin at concentrations of 10 or 100 ng/ml; (b) autoclaving 10 and 100 ng/ml ricin in DMEM at 121 °C for 30 min completely abolished activity; and (c) milk did not affect the activity of another ribosome inactivating protein, Shiga toxin type 2 (Stx2), produced by pathogenic Escherichia coli O157:H7. Unlike ricin, which is internalized into the cells via a galactose-binding site, Stx2 is internalized through the cell surface receptor glycolipid globotriasylceramides Gb3 and Gb4. These observations suggest that ricin toxicity may possibly be reduced at room temperature by a widely consumed natural liquid food.

  6. Selective inhibition of human acetylcholinesterase by xanthine derivatives: in vitro inhibition and molecular modeling investigations.

    PubMed

    Mohamed, Tarek; Osman, Wesseem; Tin, Gary; Rao, Praveen P N

    2013-08-01

    The commonly used beverage and psychostimulant caffeine is known to inhibit human acetylcholinesterase enzyme. This pharmacological activity of caffeine is partly responsible for its cognition enhancing properties. However, the exact mechanisms of its binding to human cholinesterases (acetyl and butyrylcholinesterase; hAChE and hBuChE) are not well known. In this study, we investigated the cholinesterase inhibition by the xanthine derivatives caffeine, pentoxifylline, and propentofylline. Among them, propentofylline was the most potent AChE inhibitor (hAChE IC₅₀=6.40 μM). The hAChE inhibitory potency was of the order: caffeine (hAChE IC₅₀=7.25 μM)inhibition of hAChE with no inhibition of hBuChE (IC₅₀>50 μM) relative to the reference agent donepezil (hBuChE IC₅₀=13.60 μM). Molecular modeling investigations indicate that caffeine binds primarily in the catalytic site (Ser203, Glu334 and His447) region of hAChE whereas pentoxifylline and propentofylline are able to bind to both the catalytic site and peripheral anionic site due to their increased bulk/size, thereby exhibiting superior AChE inhibition relative to caffeine. In contrast, their lack of hBuChE inhibition is due to a larger binding site and lack of key aromatic amino acids. In summary, our study has important implications in the development of novel caffeine derivatives as selective AChE inhibitors with potential application as cognitive enhancers and to treat various forms of dementia.

  7. Task Inhibition and Response Inhibition in Older vs. Younger Adults: A Diffusion Model Analysis

    PubMed Central

    Schuch, Stefanie

    2016-01-01

    Differences in inhibitory ability between older (64–79 years, N = 24) and younger adults (18–26 years, N = 24) were investigated using a diffusion model analysis. Participants performed a task-switching paradigm that allows assessing n−2 task repetition costs, reflecting inhibitory control on the level of tasks, as well as n−1 response-repetition costs, reflecting inhibitory control on the level of responses. N−2 task repetition costs were of similar size in both age groups. Diffusion model analysis revealed that for both younger and older adults, drift rate parameters were smaller in the inhibition condition relative to the control condition, consistent with the idea that persisting task inhibition slows down response selection. Moreover, there was preliminary evidence for task inhibition effects in threshold separation and non-decision time in the older, but not the younger adults, suggesting that older adults might apply different strategies when dealing with persisting task inhibition. N−1 response-repetition costs in mean RT were larger in older than younger adults, but in mean error rates tended to be larger in younger than older adults. Diffusion-model analysis revealed longer non-decision times in response repetitions than response switches in both age groups, consistent with the idea that motor processes take longer in response repetitions than response switches due to persisting response inhibition of a previously executed response. The data also revealed age-related differences in overall performance: Older adults responded more slowly and more accurately than young adults, which was reflected by a higher threshold separation parameter in diffusion model analysis. Moreover, older adults showed larger non-decision times and higher variability in non-decision time than young adults, possibly reflecting slower and more variable motor processes. In contrast, overall drift rate did not differ between older and younger adults. Taken together

  8. Reconciling the role of serotonin in behavioral inhibition and aversion: acute tryptophan depletion abolishes punishment-induced inhibition in humans.

    PubMed

    Crockett, Molly J; Clark, Luke; Robbins, Trevor W

    2009-09-23

    The neuromodulator serotonin has been implicated in a large number of affective and executive functions, but its precise contribution to motivation remains unclear. One influential hypothesis has implicated serotonin in aversive processing; another has proposed a more general role for serotonin in behavioral inhibition. Because behavioral inhibition is a prepotent reaction to aversive outcomes, it has been a challenge to reconcile these two accounts. Here, we show that serotonin is critical for punishment-induced inhibition but not overall motor response inhibition or reporting aversive outcomes. We used acute tryptophan depletion to temporarily lower brain serotonin in healthy human volunteers as they completed a novel task designed to obtain separate measures of motor response inhibition, punishment-induced inhibition, and sensitivity to aversive outcomes. After a placebo treatment, participants were slower to respond under punishment conditions compared with reward conditions. Tryptophan depletion abolished this punishment-induced inhibition without affecting overall motor response inhibition or the ability to adjust response bias in line with punishment contingencies. The magnitude of reduction in punishment-induced inhibition depended on the degree to which tryptophan depletion reduced plasma tryptophan levels. These findings extend and clarify previous research on the role of serotonin in aversive processing and behavioral inhibition and fit with current theorizing on the involvement of serotonin in predicting aversive outcomes.

  9. Inhibition of MAO by fractions and constituents of hypericum extract.

    PubMed

    Bladt, S; Wagner, H

    1994-10-01

    The inhibition of monoamine oxidase (MAO) by six fractions from hypericum extract and three characteristic constituents (as pure substances) were analyzed in vitro and ex vivo to study the antidepressive mechanism of action. Rat brain homogenates were used as the in vitro model, while the ex vivo analysis was performed after intraperitoneal application of the test substances to albino rats. Massive inhibition of MAO-A could be shown with the total extract and all fractions only at the concentration of 10(-3) mol/L. At 10(-4) mol/L, one fraction rich in flavonoides showed an inhibition of 39%, and all other fractions demonstrated less than 25% inhibition. Using pure hypericin as well as in all ex vivo experiments, no relevant inhibiting effects could be shown. From the results it can be concluded that the clinically proven antidepressive effect of hypericum extract cannot be explained in terms of MAO inhibition.

  10. Molecular mechanisms of DNA repair inhibition by caffeine

    SciTech Connect

    Selby, C.P.; Sancar, A. )

    1990-05-01

    Caffeine potentiates the mutagenic and lethal effects of genotoxic agents. It is thought that this is due, at least in some organisms, to inhibition of DNA repair. However, direct evidence for inhibition of repair enzymes has been lacking. Using purified Escherichia coli DNA photolyase and (A)BC excinuclease, we show that the drug inhibits photoreactivation and nucleotide excision repair by two different mechanisms. Caffeine inhibits photoreactivation by interfering with the specific binding of photolyase to damaged DNA, and it inhibits nucleotide excision repair by promoting nonspecific binding of the damage-recognition subunit, UvrA, of (A)BC excinuclease. A number of other intercalators, including acriflavin and ethidium bromide, appear to inhibit the excinuclease by a similar mechanism--that is, by trapping the UvrA subunit in nonproductive complexes on undamaged DNA.

  11. Engineered kinesin motor proteins amenable to small-molecule inhibition

    PubMed Central

    Engelke, Martin F.; Winding, Michael; Yue, Yang; Shastry, Shankar; Teloni, Federico; Reddy, Sanjay; Blasius, T. Lynne; Soppina, Pushpanjali; Hancock, William O.; Gelfand, Vladimir I.; Verhey, Kristen J.

    2016-01-01

    The human genome encodes 45 kinesin motor proteins that drive cell division, cell motility, intracellular trafficking and ciliary function. Determining the cellular function of each kinesin would benefit from specific small-molecule inhibitors. However, screens have yielded only a few specific inhibitors. Here we present a novel chemical-genetic approach to engineer kinesin motors that can carry out the function of the wild-type motor yet can also be efficiently inhibited by small, cell-permeable molecules. Using kinesin-1 as a prototype, we develop two independent strategies to generate inhibitable motors, and characterize the resulting inhibition in single-molecule assays and in cells. We further apply these two strategies to create analogously inhibitable kinesin-3 motors. These inhibitable motors will be of great utility to study the functions of specific kinesins in a dynamic manner in cells and animals. Furthermore, these strategies can be used to generate inhibitable versions of any motor protein of interest. PMID:27045608

  12. Firing regulation of fast-spiking interneurons by autaptic inhibition

    NASA Astrophysics Data System (ADS)

    Guo, Daqing; Chen, Mingming; Perc, Matjaž; Wu, Shengdun; Xia, Chuan; Zhang, Yangsong; Xu, Peng; Xia, Yang; Yao, Dezhong

    2016-05-01

    Fast-spiking (FS) interneurons in the brain are self-innervated by powerful inhibitory GABAergic autaptic connections. By computational modelling, we investigate how autaptic inhibition regulates the firing response of such interneurons. Our results indicate that autaptic inhibition both boosts the current threshold for action potential generation and modulates the input-output gain of FS interneurons. The autaptic transmission delay is identified as a key parameter that controls the firing patterns and determines multistability regions of FS interneurons. Furthermore, we observe that neuronal noise influences the firing regulation of FS interneurons by autaptic inhibition and extends their dynamic range for encoding inputs. Importantly, autaptic inhibition modulates noise-induced irregular firing of FS interneurons, such that coherent firing appears at an optimal autaptic inhibition level. Our results reveal the functional roles of autaptic inhibition in taming the firing dynamics of FS interneurons.

  13. Inhibition of MAO and COMT by hypericum extracts and hypericin.

    PubMed

    Thiede, H M; Walper, A

    1994-10-01

    The influence of hypericin, hypericum total extract, and hypericum fractions on the activity of MAO and COMT, prepared in vitro from pork liver, were investigated in several concentration steps. An inhibition of MAO could be shown in the following concentrations (extract correlated to a mean molecular value of 500): hypericin to 10(-3) mol/L, hypericum total extract to 10(-4) mol/L, one extract fraction up to 10(-5). A COMT inhibition could not be shown for hypericin, with hypericum extract to 10(-4) mol/L and with two extract fractions also up to 10(-4) mol/L. The MAO inhibiting fraction contained hypericins as well as flavonols, the COMT-inhibition fraction being mainly flavonols and xanthones. The concentrations of inhibition shown might not be sufficient to explain the clinically proven antidepressive effect of hypericum particularly with regard to the inhibition of MAO activity.

  14. Acute inhibition of corticosteroidogenesis by inhibitors of calmodulin action.

    PubMed

    Carsia, R V; Moyle, W R; Wolff, D J; Malamed, S

    1982-11-01

    To identify the possible role of calmodulin in ACTH function, we tested the ability of chlorpromazine (CP) and other calmodulin antagonists to inhibit steroidogenesis of isolated adrenocortical cells of the rat. CP reversibly inhibited maximal ACTH-induced corticosterone (B) production. The presence of the drug did not alter the ED50 of ACTH stimulation (3.2 X 10(3) pg/ml), suggesting that it inhibited ACTH-induced steroidogenesis in a noncompetitive manner. The CP concentration required for half-maximal inhibition was 8.2 microM, a value close to the dissociation constant of the CP-calmodulin complex (5.3 microM). Concentrations greater than 40 microM resulted in complete inhibition. Similar concentrations of CP inhibited ACTH-induced cAMP accumulation in a dose-dependent manner, indicating an effect of the drug on early events in ACTH action. In addition, CP also apparently acted at a site distal to the point of cAMP formation, as shown by the finding that it inhibited cAMP-induced B production. CP inhibition of ACTH-induced B production was independent of the Ca2+ concentration, suggesting that the drug did not compete with Ca2+ directly. Concentrations of CP greater than 20 microM inhibited protein synthesis as measured by leucine incorporation into cellular proteins. Thus, although the inhibitory effect of high concentrations of CP on steroidogenesis might be explained by an effect on protein synthesis, the inhibition seen at 10 microM appeared to be independent of protein synthesis. Other antagonists of calmodulin action inhibited maximal ACTH-induced B production with the following relative potencies: trifluoperazine greater than CP greater than haloperidol greater than chlordiazepoxide. This order is similar to that reported for inhibition of calmodulin-activated phosphodiesterase and for binding to calmodulin. These findings suggest that calmodulin may modulate the effect of ACTH on steroidogenesis at multiple sites.

  15. Method for inhibiting oxidation of metal sulfide-containing material

    DOEpatents

    Elsetinow, Alicia; Borda, Michael J.; Schoonen, Martin A.; Strongin, Daniel R.

    2006-12-26

    The present invention provides means for inhibiting the oxidation of a metal sulfide-containing material, such as ore mine waste rock or metal sulfide taiulings, by coating the metal sulfide-containing material with an oxidation-inhibiting two-tail lipid coating (12) thereon, thereby inhibiting oxidation of the metal sulfide-containing material in acid mine drainage conditions. The lipids may be selected from phospholipids, sphingolipids, glycolipids and combinations thereof.

  16. High molecular weight polysaccharide that binds and inhibits virus

    DOEpatents

    Konowalchuk, Thomas W

    2014-01-14

    This invention provides a high molecular weight polysaccharide capable of binding to and inhibiting virus and related pharmaceutical formulations and methods on inhibiting viral infectivity and/or pathogenicity, as well as immunogenic compositions. The invention further methods of inhibiting the growth of cancer cells and of ameliorating a symptom of aging. Additionally, the invention provides methods of detecting and/or quantifying and/or isolating viruses.

  17. Activating Cell Death Ligand Signaling Through Proteasome Inhibition

    DTIC Science & Technology

    2009-05-01

    Activating Cell Death Ligand Signaling Through Proteasome Inhibition PRINCIPAL INVESTIGATOR: Steven R Schwarze...SUBTITLE Activating Cell Death Ligand Signaling Through 5a. CONTRACT NUMBER Proteasome Inhibition 5b. GRANT NUMBER W81XWH-08-1-0392 5c...proteasome inhibition can act as an anti-neoplastic agent in vivo by sensitizing cancer cells to cell death ligands in the tumor microenvironment

  18. Corrosion inhibiting media for pressurized water reactor steam generators

    SciTech Connect

    Panson, A.J.

    1988-08-16

    A method is described for inhibiting carbon steel corrosion in the secondary system of a nuclear steam generator comprising: providing a corrosion inhibiting quantity of boric acid in the secondary system water; and incorporating in the boric acid containing secondary system water, an activating amount of a polyhydric compound sufficient to increase the acid strength of the boric acid and improve the corrosion inhibiting characteristics thereof.

  19. PPARγ ligands inhibit primary tumor growth and metastasis by inhibiting angiogenesis

    PubMed Central

    Panigrahy, Dipak; Singer, Samuel; Shen, Lucy Q.; Butterfield, Catherine E.; Freedman, Deborah A.; Chen, Emy J.; Moses, Marsha A.; Kilroy, Susan; Duensing, Stefan; Fletcher, Christopher; Fletcher, Jonathan A.; Hlatky, Lynn; Hahnfeldt, Philip; Folkman, Judah; Kaipainen, Arja

    2002-01-01

    Several drugs approved for a variety of indications have been shown to exhibit antiangiogenic effects. Our study focuses on the PPARγ ligand rosiglitazone, a compound widely used in the treatment of type 2 diabetes. We demonstrate, for the first time to our knowledge, that PPARγ is highly expressed in tumor endothelium and is activated by rosiglitazone in cultured endothelial cells. Furthermore, we show that rosiglitazone suppresses primary tumor growth and metastasis by both direct and indirect antiangiogenic effects. Rosiglitazone inhibits bovine capillary endothelial cell but not tumor cell proliferation at low doses in vitro and decreases VEGF production by tumor cells. In our in vivo studies, rosiglitazone suppresses angiogenesis in the chick chorioallantoic membrane, in the avascular cornea, and in a variety of primary tumors. These results suggest that PPARγ ligands may be useful in treating angiogenic diseases such as cancer by inhibiting angiogenesis. PMID:12370270

  20. Selective Inhibition of Bacterial Topoisomerase I by alkynyl-bisbenzimidazoles†

    PubMed Central

    Ranjan, Nihar; Fulcrand, Geraldine; King, Ada; Brown, Joseph; Jiang, Xiuping; Leng, Fenfei; Arya, Dev P.

    2014-01-01

    Hoechst dyes are well known DNA binders that non-selectively inhibit the function of mammalian topoisomerase I and II. Herein, we show that Hoechst 33258 based bisbenzimidazoles (DPA 151–154), containing a terminal alkyne, are effective and selective inhibitors of E. coli. topoisomerase I. These bisbenzimidazoles displayed topoisomerase I inhibition much better than Hoechst 33342 or Hoechst 33258 with IC50 values in the range of 2.47–6.63 μM. Bisbenzimidazoles DPA 151-154 also display selective inhibition of E. coli. topoisomerase I over DNA gyrase and Human topoisomerases I and II, and effectively inhibit bacterial growth. PMID:25083189

  1. Selenotrisulfide inhibits initiation by RNA polymerase II but not elongation

    SciTech Connect

    Frenkel, G.D.; Falvey, D.

    1989-03-01

    We previously reported that RNA polymerase II (purified from wheat germ) is inhibited by selenotrisulfides, the products of the reaction of selenite with sulfhydryl compounds. We have now found that the initiation stage of the reaction is inhibited by selenotrisulfide but the elongation stage of the reaction is not. The actual start of the RNA chain is not inhibited by the selenotrisulfide, but rather the formation of the enzyme-DNA binary complex. Selenotrisulfide has a similar differential effect on initiation and elongation by RNA polymerase II from HeLa cells; in contrast, with E. coli RNA polymerase, it inhibits elongation as well.

  2. Cognitive inhibition in students with and without dyslexia and dyscalculia.

    PubMed

    Wang, Li-Chih; Tasi, Hung-Ju; Yang, Hsien-Ming

    2012-01-01

    The present study presents a comparison of the cognitive inhibition abilities of dyslexic, dyscalculic, and control students. The participants were 45 dyslexic students, 45 dyscalculic students, and 45 age-, gender-, and IQ-matched control students. The major evaluation tools included six cognitive inhibition tasks which were restructured during principal component analysis into three categories: graph inhibition, number inhibition, and word inhibition. Comparisons of the 3 groups of students revealed that in graph inhibition, dyscalculic students performed worst of the 3 groups, with dyslexic students also performing worse than control students in this category. For number inhibition, the control students' performances were equal to those of dyslexic students, with both groups performing better than dyscalculic students. For word inhibition, control students' performances were equal to those of dyscalculic students; both groups had shorter response times and lower incorrect rates than dyslexic students. These results suggest the complexity of the different cognitive inhibition abilities displayed by dyslexic, dyscalculic, and control students. However, some regular patterns occurred.

  3. Schedule of Punishment and Inhibition of Aggression in Children

    ERIC Educational Resources Information Center

    Parke, Ross D.; Deur, Jan L.

    1972-01-01

    Data showed that consistent punishment resulted in faster inhibition than inconsistent punishment; subjects who were punished showed less persistence than subjects placed on an extinction schedule. (Authors)

  4. Targeted inhibition of Src kinase signaling attenuates pancreatic tumorigenesis

    PubMed Central

    Nagaraj, Nagathihalli S.; Smith, J. Joshua; Revetta, Frank; Washington, M. Kay; Merchant, Nipun B.

    2012-01-01

    Elevated Src expression correlates with malignant potential and metastatic disease in many tumors including pancreas cancer. We sought to characterize the molecular effects of Src kinase inhibition with dasatinib (BMS-354825) a novel, multi-targeted kinase inhibitor that targets Src family kinases, in pancreas ductal adenocarcinoma (PDA). We identified sensitive and resistant PDA cell lines to dasatinib treatment and tested the molecular effects of Src inhibition in vitro and in vivo. We show for the first time that cellular localization of Src expression impacts survival in patients with PDA. Pancreas tumors with increased membranous expression of Src result in decreased survival compared with tumors that have increased cytoplasmic Src expression. Src kinase inhibition with dasatinib markedly inhibits cell proliferation, migration, invasion, cell cycle progression and anchorage independent growth and stimulates apoptosis. This is accompanied by decreased phosphorylation of Src, FAK, paxillin, AKT, STAT3, ERK, JNK and MAPK, as well as decreased cyclinD1 expression in a time and concentration-dependent manner. Furthermore, siRNA to Src results in significant decrease in cell proliferation, invasion and migration of pancreas cancer cells. Dasatinib treatment also inhibits in vivo pancreas tumor growth. Mechanisms of resistance to Src inhibition appear to be related to a lack of inhibition of STAT3 and MAPK signaling. These results establish a mechanistic rationale for Src inhibition with dasatinib as a therapeutic target in the treatment of pancreas cancer and identify potential biomarkers of resistance to Src inhibition. PMID:20682659

  5. Timing of growth inhibition following shoot inversion in Pharbitis nil

    NASA Technical Reports Server (NTRS)

    Abdel-Rahman, A. M.; Cline, M. G.

    1989-01-01

    Shoot inversion in Pharbitis nil results in the enhancement of ethylene production and in the inhibition of elongation in the growth zone of the inverted shoot. The initial increase in ethylene production previously was detected within 2 to 2.75 hours after inversion. In the present study, the initial inhibition of shoot elongation was detected within 1.5 to 4 hours with a weighted mean of 2.4 hours. Ethylene treatment of upright shoots inhibited elongation in 1.5 hours. A cause and effect relationship between shoot inversion-enhanced ethylene production and inhibition of elongation cannot be excluded.

  6. The inhibition capacities of children with mathematical disabilities.

    PubMed

    Censabella, Sandrine; Noël, Marie-Pascale

    2008-01-01

    Several authors have argued that mathematical disabilities might result from difficulties in inhibiting irrelevant information. The present study addresses this issue by assessing three inhibition functions in 40 ten-year-old children: suppression of irrelevant information from working memory, inhibition of prepotent responses, and interference control. We found no significant differences between children with math disabilities and typically achieving controls, or between children with arithmetic facts disabilities and children with above-average arithmetic facts skills. These findings, along with other empirical evidence and with theoretical considerations, cast doubt on the inhibition deficit hypothesis.

  7. Licochalcones extracted from Glycyrrhiza inflata inhibit platelet aggregation accompanied by inhibition of COX-1 activity

    PubMed Central

    Okuda-Tanino, Asa; Sugawara, Daiki; Tashiro, Takumi; Iwashita, Masaya; Obara, Yutaro; Moriya, Takahiro; Tsushima, Chisato; Saigusa, Daisuke; Tomioka, Yoshihisa; Ishii, Kuniaki; Nakahata, Norimichi

    2017-01-01

    Licochalcones extracted from Glycyrrhiza inflata are known to have a variety of biological properties such as anti-inflammatory, anti-bacterial, and anti-tumor activities, but their action on platelet aggregation has not yet been reported. Therefore, in this study we investigated the effects of licochalcones on platelet aggregation. Collagen and U46619, a thromboxane A2 receptor agonist, caused rabbit platelet aggregation, which was reversed by pretreatment with licochalcones A, C and D in concentration-dependent manners. Among these compounds, licochalcone A caused the most potent inhibitory effect on collagen-induced platelet aggregation. However, the licochalcones showed marginal inhibitory effects on thrombin or ADP-induced platelet aggregation. In addition to rabbit platelets, licochalcone A attenuated collagen-induced aggregation in human platelets. Because licochalcone A also inhibited arachidonic acid-induced platelet aggregation and production of thromboxane A2 induced by collagen in intact platelets, we further examined the direct interaction of licochalcone A with cyclooxygenase (COX)-1. As expected, licochalcone A caused an inhibitory effect on both COX-1 and COX-2 in vitro. Regarding the effect of licochalcone A on COX-1 enzyme reaction kinetics, although licochalcone A showed a stronger inhibition of prostaglandin E2 synthesis induced by lower concentrations of arachidonic acid, Vmax values in the presence or absence of licochalcone A were comparable, suggesting that it competes with arachidonic acid at the same binding site on COX-1. These results suggest that licochalcones inhibit collagen-induced platelet aggregation accompanied by inhibition of COX-1 activity. PMID:28282426

  8. Licochalcones extracted from Glycyrrhiza inflata inhibit platelet aggregation accompanied by inhibition of COX-1 activity.

    PubMed

    Okuda-Tanino, Asa; Sugawara, Daiki; Tashiro, Takumi; Iwashita, Masaya; Obara, Yutaro; Moriya, Takahiro; Tsushima, Chisato; Saigusa, Daisuke; Tomioka, Yoshihisa; Ishii, Kuniaki; Nakahata, Norimichi

    2017-01-01

    Licochalcones extracted from Glycyrrhiza inflata are known to have a variety of biological properties such as anti-inflammatory, anti-bacterial, and anti-tumor activities, but their action on platelet aggregation has not yet been reported. Therefore, in this study we investigated the effects of licochalcones on platelet aggregation. Collagen and U46619, a thromboxane A2 receptor agonist, caused rabbit platelet aggregation, which was reversed by pretreatment with licochalcones A, C and D in concentration-dependent manners. Among these compounds, licochalcone A caused the most potent inhibitory effect on collagen-induced platelet aggregation. However, the licochalcones showed marginal inhibitory effects on thrombin or ADP-induced platelet aggregation. In addition to rabbit platelets, licochalcone A attenuated collagen-induced aggregation in human platelets. Because licochalcone A also inhibited arachidonic acid-induced platelet aggregation and production of thromboxane A2 induced by collagen in intact platelets, we further examined the direct interaction of licochalcone A with cyclooxygenase (COX)-1. As expected, licochalcone A caused an inhibitory effect on both COX-1 and COX-2 in vitro. Regarding the effect of licochalcone A on COX-1 enzyme reaction kinetics, although licochalcone A showed a stronger inhibition of prostaglandin E2 synthesis induced by lower concentrations of arachidonic acid, Vmax values in the presence or absence of licochalcone A were comparable, suggesting that it competes with arachidonic acid at the same binding site on COX-1. These results suggest that licochalcones inhibit collagen-induced platelet aggregation accompanied by inhibition of COX-1 activity.

  9. Ischemia/reperfusion injury: effect of simultaneous inhibition of plasma cascade systems versus specific complement inhibition.

    PubMed

    Duehrkop, Claudia; Rieben, Robert

    2014-03-01

    Ischemia/reperfusion injury (IRI) may occur from ischemia due to thrombotic occlusion, trauma or surgical interventions, including transplantation, with subsequent reestablishment of circulation. Time-dependent molecular and structural changes result from the deprivation of blood and oxygen in the affected tissue during ischemia. Upon restoration of blood flow a multifaceted network of plasma cascades is activated, including the complement-, coagulation-, kinin-, and fibrinolytic system, which plays a major role in the reperfusion-triggered inflammatory process. The plasma cascade systems are therefore promising therapeutic targets for attenuation of IRI. Earlier studies showed beneficial effects through inhibition of the complement system using specific complement inhibitors. However, pivotal roles in IRI are also attributed to other cascades. This raises the question, whether drugs, such as C1 esterase inhibitor, which regulate more than one cascade at a time, have a higher therapeutic potential. The present review discusses different therapeutic approaches ranging from specific complement inhibition to simultaneous inhibition of plasma cascade systems for reduction of IRI, gives an overview of the plasma cascade systems in IRI as well as highlights recent findings in this field.

  10. Crizotinib inhibits NF2-associated schwannoma through inhibition of focal adhesion kinase 1

    PubMed Central

    Troutman, Scott; Moleirinho, Susana; Kota, Smitha; Nettles, Kendall; Fallahi, Mohammad; Johnson, Gary L.; Kissil, Joseph L.

    2016-01-01

    Neurofibromatosis type 2 (NF2) is a dominantly inherited autosomal disease characterized by schwannomas of the 8th cranial nerve. The NF2 tumor suppressor gene encodes for Merlin, a protein implicated as a suppressor of multiple cellular signaling pathways. To identify potential drug targets in NF2-associated malignancies we assessed the consequences of inhibiting the tyrosine kinase receptor MET. We identified crizotinib, a MET and ALK inhibitor, as a potent inhibitor of NF2-null Schwann cell proliferation in vitro and tumor growth in vivo. To identify the target/s of crizotnib we employed activity-based protein profiling (ABPP), leading to identification of FAK1 (PTK2) as the relevant target of crizotinib inhibition in NF2-null schwannoma cells. Subsequent studies confirm that inhibition of FAK1 is sufficient to suppress tumorigenesis in animal models of NF2 and that crizotinib-resistant forms of FAK1 can rescue the effects of treatment. These studies identify a FDA approved drug as a potential treatment for NF2 and delineate the mechanism of action in NF2-null Schwann cells. PMID:27363027

  11. Autophagy inhibition overcomes multiple mechanisms of resistance to BRAF inhibition in brain tumors

    PubMed Central

    Mulcahy Levy, Jean M; Zahedi, Shadi; Griesinger, Andrea M; Morin, Andrew; Davies, Kurtis D; Aisner, Dara L; Kleinschmidt-DeMasters, BK; Fitzwalter, Brent E; Goodall, Megan L; Thorburn, Jacqueline; Amani, Vladimir; Donson, Andrew M; Birks, Diane K; Mirsky, David M; Hankinson, Todd C; Handler, Michael H; Green, Adam L; Vibhakar, Rajeev; Foreman, Nicholas K; Thorburn, Andrew

    2017-01-01

    Kinase inhibitors are effective cancer therapies, but tumors frequently develop resistance. Current strategies to circumvent resistance target the same or parallel pathways. We report here that targeting a completely different process, autophagy, can overcome multiple BRAF inhibitor resistance mechanisms in brain tumors. BRAFV600Emutations occur in many pediatric brain tumors. We previously reported that these tumors are autophagy-dependent and a patient was successfully treated with the autophagy inhibitor chloroquine after failure of the BRAFV600E inhibitor vemurafenib, suggesting autophagy inhibition overcame the kinase inhibitor resistance. We tested this hypothesis in vemurafenib-resistant brain tumors. Genetic and pharmacological autophagy inhibition overcame molecularly distinct resistance mechanisms, inhibited tumor cell growth, and increased cell death. Patients with resistance had favorable clinical responses when chloroquine was added to vemurafenib. This provides a fundamentally different strategy to circumvent multiple mechanisms of kinase inhibitor resistance that could be rapidly tested in clinical trials in patients with BRAFV600E brain tumors. DOI: http://dx.doi.org/10.7554/eLife.19671.001 PMID:28094001

  12. Linalool inhibits cigarette smoke-induced lung inflammation by inhibiting NF-κB activation.

    PubMed

    Ma, Jianqun; Xu, Hai; Wu, Jun; Qu, Changfa; Sun, Fenglin; Xu, Shidong

    2015-12-01

    Linalool, a natural compound that exists in the essential oils of several aromatic plants species, has been reported to have anti-inflammatory effects. However, the effects of linalool on cigarette smoke (CS)-induced acute lung inflammation have not been reported. In the present study, we investigated the protective effects of linalool on CS-induced acute lung inflammation in mice. Linalool was given i.p. to mice 2h before CS exposure daily for five consecutive days. The numbers of macrophages and neutrophils in bronchoalveolar lavage fluid (BALF) were measured. The production of TNF-α, IL-6, IL-1β, IL-8 and MCP-1 were detected by ELISA. The expression of NF-κB was detected by Western blotting. Our results showed that treatment of linalool significantly attenuated CS-induced lung inflammation, coupled with inhibited the infiltration of inflammatory cells and TNF-α, IL-6, IL-1β, IL-8 and MCP-1 production. Meanwhile, treatment of linalool inhibited CS-induced lung MPO activity and pathological changes. Furthermore, linalool suppressed CS-induced NF-κB activation in a dose-dependent manner. In conclusion, our results demonstrated that linalool protected against CS-induced lung inflammation through inhibiting CS-induced NF-κB activation.

  13. Imeglimin prevents human endothelial cell death by inhibiting mitochondrial permeability transition without inhibiting mitochondrial respiration

    PubMed Central

    Detaille, D; Vial, G; Borel, A-L; Cottet-Rouselle, C; Hallakou-Bozec, S; Bolze, S; Fouqueray, P; Fontaine, E

    2016-01-01

    Imeglimin is the first in a new class of oral glucose-lowering agents, having recently completed its phase 2b trial. As Imeglimin did show a full prevention of β-cell apoptosis, and since angiopathy represents a major complication of diabetes, we studied Imeglimin protective effects on hyperglycemia-induced death of human endothelial cells (HMEC-1). These cells were incubated in several oxidative stress environments (exposure to high glucose and oxidizing agent tert-butylhydroperoxide) which led to mitochondrial permeability transition pore (PTP) opening, cytochrome c release and cell death. These events were fully prevented by Imeglimin treatment. This protective effect on cell death occurred without any effect on oxygen consumption rate, on lactate production and on cytosolic redox or phosphate potentials. Imeglimin also dramatically decreased reactive oxygen species production, inhibiting specifically reverse electron transfer through complex I. We conclude that Imeglimin prevents hyperglycemia-induced cell death in HMEC-1 through inhibition of PTP opening without inhibiting mitochondrial respiration nor affecting cellular energy status. Considering the high prevalence of macrovascular and microvascular complications in type 2 diabetic subjects, these results together suggest a potential benefit of Imeglimin in diabetic angiopathy. PMID:27551496

  14. Vitamin K3 (menadione) redox cycling inhibits cytochrome P450-mediated metabolism and inhibits parathion intoxication.

    PubMed

    Jan, Yi-Hua; Richardson, Jason R; Baker, Angela A; Mishin, Vladimir; Heck, Diane E; Laskin, Debra L; Laskin, Jeffrey D

    2015-10-01

    Parathion, a widely used organophosphate insecticide, is considered a high priority chemical threat. Parathion toxicity is dependent on its metabolism by the cytochrome P450 system to paraoxon (diethyl 4-nitrophenyl phosphate), a cytotoxic metabolite. As an effective inhibitor of cholinesterases, paraoxon causes the accumulation of acetylcholine in synapses and overstimulation of nicotinic and muscarinic cholinergic receptors, leading to characteristic signs of organophosphate poisoning. Inhibition of parathion metabolism to paraoxon represents a potential approach to counter parathion toxicity. Herein, we demonstrate that menadione (methyl-1,4-naphthoquinone, vitamin K3) is a potent inhibitor of cytochrome P450-mediated metabolism of parathion. Menadione is active in redox cycling, a reaction mediated by NADPH-cytochrome P450 reductase that preferentially uses electrons from NADPH at the expense of their supply to the P450s. Using human recombinant CYP 1A2, 2B6, 3A4 and human liver microsomes, menadione was found to inhibit the formation of paraoxon from parathion. Administration of menadione bisulfite (40mg/kg, ip) to rats also reduced parathion-induced inhibition of brain cholinesterase activity, as well as parathion-induced tremors and the progression of other signs and symptoms of parathion poisoning. These data suggest that redox cycling compounds, such as menadione, have the potential to effectively mitigate the toxicity of organophosphorus pesticides including parathion which require cytochrome P450-mediated activation.

  15. Inhibition of autophagy inhibits the conversion of cardiac fibroblasts to cardiac myofibroblasts

    PubMed Central

    Gupta, Shivika S.; Zeglinski, Matthew R.; Rattan, Sunil G.; Landry, Natalie M.; Ghavami, Saeid; Wigle, Jeffrey T.; Klonisch, Thomas; Halayko, Andrew J.; Dixon, Ian M.C.

    2016-01-01

    The incidence of heart failure with concomitant cardiac fibrosis is very high in developed countries. Fibroblast activation in heart is causal to cardiac fibrosis as they convert to hypersynthetic cardiac myofibroblasts. There is no known treatment for cardiac fibrosis. Myofibroblasts contribute to the inappropriate remodeling of the myocardial interstitium, which leads to reduced cardiac function and ultimately heart failure. Elevated levels of autophagy have been linked to stress-induced ventricular remodeling and other cardiac diseases. Previously, we had shown that TGF-β1 treatment of human atrial fibroblasts both induced autophagy and enhanced the fibrogenic response supporting a linkage between the myofibroblast phenotype and autophagy. We now demonstrate that with in vitro culture of primary rat cardiac fibroblasts, inhibition of autophagy represses fibroblast to myofibroblast phenoconversion. Culturing unpassaged cardiac fibroblasts for 72 hours on plastic tissue culture plates is associated with elevated α-smooth muscle actin (α-SMA) expression. This activation parallels increased microtubule-associated protein 1A/1B-light chain 3 (LC-3β II) protein expression. Inhibition of autophagy with bafilomycin-A1 (Baf-A1) and chloroquine (CQ) in cardiac fibroblasts significantly reduces α-SMA and extracellular domain A fibronectin (ED-A FN) protein vs untreated controls. Myofibroblast cell migration and contractility were significantly reduced following inhibition of autophagy. These data support the possibility of a causal link between cardiac fibroblast-to-myofibroblast phenoconversion and autophagy. PMID:27705938

  16. Quercetin inhibited cadmium-induced autophagy in the mouse kidney via inhibition of oxidative stress

    PubMed Central

    Yuan, Yuan; Ma, Shixun; Qi, Yongmei; Wei, Xue; Cai, Hui; Dong, Li; Lu, Yufeng; Zhang, Yupeng; Guo, Qingjin

    2016-01-01

    The objective of the current study was to explore the inhibitory effects of quercetin on cadmium-induced autophagy in mouse kidneys. Mice were intraperitoneally injected with cadmium and quercetin once daily for 3 days. The LC3-II/β-actin ratio was used as the autophagy marker, and autophagy was observed by transmission electron microscopy. Oxidative stress was investigated in terms of reactive oxygen species, total antioxidant capacity, and malondialdehyde. Cadmium significantly induced typical autophagosome formation, increased the LC3-II/β-actin ratio, reactive oxygen species level, and malondialdehyde content, and decreased total antioxidant capacity. Interestingly, quercetin markedly decreased the cadmium-induced LC3-II/β-actin ratio, reactive oxygen species levels, and malondialdehyde content, and simultaneously increased total antioxidant capacity. Cadmium can inhibit total antioxidant capacity, produce a large amount of reactive oxygen species, lead to oxidative stress, and promote lipid peroxidation, eventually inducing autophagy in mouse kidneys. Quercetin could inhibit cadmium-induced autophagy via inhibition of oxidative stress. This study may provide a theoretical basis for the treatment of cadmium injury. PMID:27821909

  17. The effect of age on inhibition of return is independent of non-ocular response inhibition.

    PubMed

    Poliakoff, Ellen; Coward, Rachel S; Lowe, Christine; O'Boyle, Donald J

    2007-01-28

    Inhibition of return (IOR) refers to the slowing of a response to a target stimulus presented in the same location as a previous stimulus. Increased IOR has been observed in older adults, despite a reduction in other 'inhibitory' processes. However, cue-target tasks have been used in all previous studies and because of this, IOR may have been overestimated due to non-ocular response inhibition associated with withholding a response from the cue. Could increased levels of response inhibition account for the observations of increased IOR in older adults? This confound can be circumvented by using a target-target paradigm, in which a response is made to all stimuli. We tested three groups of 24 subjects: young (mean 22.5 years), young-old (mean 61.9 years) and old-old (mean 74.8 years). Subjects completed both visual cue-target and target-target tasks with identical inter-stimulus intervals of 1400 and 1800ms. IOR magnitude increased with age in both the cue-target task and the target-target task. Furthermore, the magnitude of visual IOR was found to increase with age even when individual differences in baseline response speed were taken into account. Thus, there appears to be a genuine increase in IOR magnitude with age.

  18. Inhibiting the HSP90 chaperone destabilizes macrophage migration inhibitory factor and thereby inhibits breast tumor progression

    PubMed Central

    Schulz, Ramona; Marchenko, Natalia D.; Holembowski, Lena; Fingerle-Rowson, Günter; Pesic, Marina; Zender, Lars; Dobbelstein, Matthias

    2012-01-01

    Intracellular macrophage migration inhibitory factor (MIF) often becomes stabilized in human cancer cells. MIF can promote tumor cell survival, and elevated MIF protein correlates with tumor aggressiveness and poor prognosis. However, the molecular mechanism facilitating MIF stabilization in tumors is not understood. We show that the tumor-activated HSP90 chaperone complex protects MIF from degradation. Pharmacological inhibition of HSP90 activity, or siRNA-mediated knockdown of HSP90 or HDAC6, destabilizes MIF in a variety of human cancer cells. The HSP90-associated E3 ubiquitin ligase CHIP mediates the ensuing proteasome-dependent MIF degradation. Cancer cells contain constitutive endogenous MIF–HSP90 complexes. siRNA-mediated MIF knockdown inhibits proliferation and triggers apoptosis of cultured human cancer cells, whereas HSP90 inhibitor-induced apoptosis is overridden by ectopic MIF expression. In the ErbB2 transgenic model of human HER2-positive breast cancer, genetic ablation of MIF delays tumor progression and prolongs overall survival of mice. Systemic treatment with the HSP90 inhibitor 17AAG reduces MIF expression and blocks growth of MIF-expressing, but not MIF-deficient, tumors. Together, these findings identify MIF as a novel HSP90 client and suggest that HSP90 inhibitors inhibit ErbB2-driven breast tumor growth at least in part by destabilizing MIF. PMID:22271573

  19. Inhibition of CaMKK2 Stimulates Osteoblast Formation and Inhibits Osteoclast Differentiation

    PubMed Central

    Cary, Rachel L.; Waddell, Seid; Racioppi, Luigi; Long, Fanxin; Novack, Deborah V.; Voor, Michael J.; Sankar, Uma

    2013-01-01

    Bone remodeling, a physiological process characterized by bone formation by osteoblasts (OB) and resorption of pre-existing bone matrix by osteoclasts (OC), is vital for the maintenance of healthy bone tissue in adult humans. Imbalances in this vital process result in pathological conditions including osteoporosis. Owing to its initial asymptomatic nature, osteoporosis is often detected only after the patient has sustained significant bone loss or a fracture. Hence, anabolic therapeutics that stimulates bone accrual is in high clinical demand. Here we identify Ca2+/calmodulin (CaM)-dependent protein kinase kinase 2 (CaMKK2) as a potential target for such therapeutics, as its inhibition enhances OB differentiation and bone growth and suppresses OC differentiation. Mice null for CaMKK2 possess higher trabecular bone mass in their long bones, along with significantly more OBs and fewer multinuclear OCs. Whereas Camkk2−/− MSCs yield significantly higher numbers of OBs, bone marrow cells from Camkk2−/− mice produce fewer multinuclear OCs, in vitro. Acute inhibition of CaMKK2 by its selective, cell-permeable pharmacological inhibitor STO-609 also results in increased OB and diminished OC formation. Further, we find phospho-protein kinase A (PKA) and Ser133 phosphorylated form of cyclic adenosine monophosphate (cAMP) response element binding protein (pCREB) to be markedly elevated in OB progenitors deficient in CaMKK2. On the other hand, genetic ablation of CaMKK2 or its pharmacological inhibition in OC progenitors results in reduced pCREB as well as significantly reduced levels of its transcriptional target, nuclear factor of activated T cells c1 (NFATc1). Moreover, in vivo administration of STO-609 results in increased OBs and diminished OCs, conferring significant protection from ovariectomy (OVX)-induced osteoporosis in adult mice. Overall, our findings reveal a novel function for CaMKK2 in bone remodeling and highlight the potential for its therapeutic

  20. Optogenetic Visualization of Presynaptic Tonic Inhibition of Cerebellar Parallel Fibers

    PubMed Central

    Berglund, Ken; Wen, Lei; Dunbar, Robert L.; Feng, Guoping

    2016-01-01

    Tonic inhibition was imaged in cerebellar granule cells of transgenic mice expressing the optogenetic chloride indicator, Clomeleon. Blockade of GABAA receptors substantially reduced chloride concentration in granule cells due to block of tonic inhibition. This indicates that tonic inhibition is a significant contributor to the resting chloride concentration of these cells. Tonic inhibition was observed not only in granule cell bodies, but also in their axons, the parallel fibers (PFs). This presynaptic tonic inhibition could be observed in slices both at room and physiological temperatures, as well as in vivo, and has many of the same properties as tonic inhibition measured in granule cel