scholarly journals Assessment of the Effectiveness of Ectomycorrhizal Inocula to Promote Growth and Root Ectomycorrhizal Colonization inPinus patulaSeedlings Using the Most Probable Number Technique

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Manuel Restrepo-Llano ◽  
Nelson W. Osorio ◽  
Juan D. León
Keyword(s):  
Root Colonization ◽  
Most Probable Number ◽  
Pinus Patula ◽  
Forest Plantations ◽  
High Quality ◽  
Probable Number ◽  
Key Factor ◽  
Ectomycorrhizal Colonization ◽  
Forest Nurseries

The aim of this study was to evaluate the response ofPinus patulaseedlings to two inocula types: soil from aPinusplantation (ES) and anin vitroproduced inoculum (EM). The most probable number method (MPN) was used to quantify ectomycorrhizal propagule density (EPD) in both inocula in a 7-order dilution series ranging from 100(undiluted inoculum) to 10−6(the most diluted inoculum). The MPN method allowed establishing differences in the number of infective ectomycorrhizal propagules’ density (EPD) (ES=34per g;EM=156per g). The results suggest that the EPD of an inoculum may be a key factor that influences the successfulness of the inoculation. The low EPD of the ES inoculum suggests that soil extracted from forest plantations had very low effectiveness for promoting root colonization and plant growth. In contrast, the high EPD found in the formulated inoculum (EM) reinforced the idea that it is better to use proven high quality inocula for forest nurseries than using soil from a forestry plantation.

scholarly journals Fabrication and Characterization of Antimicrobial Magnetron Cosputtered TiO2/Ag/Cu Composite Coatings

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 473
Author(s):  
Dilyana Gospodonova ◽  
Iliana Ivanova ◽  
Todorka Vladkova
Keyword(s):  
Antimicrobial Activity ◽  
Composite Coatings ◽  
Surface Characteristics ◽  
Standard Test ◽  
Most Probable Number ◽  
Bacterial Strains ◽  
Probable Number ◽  
Fabrication And Characterization

The aim of this study was to prepare TiO2/Ag/Cu magnetron co-sputtered coatings with controlled characteristics and to correlate them with the antimicrobial activity of the coated glass samples. The elemental composition and distribution, surface morphology, wettability, surface energy and its component were estimated as the surface characteristics influencing the bioadhesion. Well expressed, specific, Ag/Cu concentration-dependent antimicrobial activity in vitro was demonstrated toward Gram-negative and Gram-positive standard test bacterial strains both by diffusion 21 assay and by Most Probable Number of surviving cells. Direct contact and eluted silver/coper nanoparticles killing were experimentally demonstrated as a mode of the antimicrobial action of the studied TiO2/Ag/Cu thin composite coatings. It is expected that they would ensure a broad spectrum bactericidal activity during the indwelling of the coated medical devices and for at least 12 h after that, with the supposition that the benefits will be over a longer time.

scholarly journals Difference in persistent tuberculosis bacteria between in vitro and sputum from patients: implications for translational predictions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Alan Faraj ◽  
Oskar Clewe ◽  
Robin J. Svensson ◽  
Galina V. Mukamolova ◽  
Michael R. Barer ◽  
...  
Keyword(s):  
Drug Response ◽  
Most Probable Number ◽  
Sputum Smear ◽  
Probable Number ◽  
Phenotypic Resistance ◽  
Phenotypic Differences ◽  
Model Based ◽  
Persistent Bacteria ◽  
The Difference

Abstract This study aimed to investigate the number of persistent bacteria in sputum from tuberculosis patients compared to in vitro and to suggest a model-based approach for accounting for the potential difference. Sputum smear positive patients (n = 25) provided sputum samples prior to onset of chemotherapy. The number of cells detected by conventional agar colony forming unit (CFU) and most probable number (MPN) with Rpf supplementation were quantified. Persistent bacteria was assumed to be the difference between MPNrpf and CFU. The difference in persistent bacteria between in vitro and human sputum prior to chemotherapy was quantified using different model-based approaches. The persistent bacteria in sputum was 17% of the in vitro levels, suggesting a difference in phenotypic resistance, whereas no difference was found for multiplying bacterial subpopulations. Clinical trial simulations showed that the predicted time to 2 log fall in MPNrpf in a Phase 2a setting using in vitro pre-clinical efficacy information, would be almost 3 days longer if drug response was predicted ignoring the difference in phenotypic resistance. The discovered phenotypic differences between in vitro and humans prior to chemotherapy could have implications on translational efforts but can be accounted for using a model-based approach for translating in vitro to human drug response.

scholarly journals Chlorine Dioxide Inactivation ofCryptosporidium parvum Oocysts and Bacterial Spore Indicators

2001 ◽  
Vol 67 (7) ◽  
pp. 2993-3001 ◽  
Author(s):  
Christian P. Chauret ◽  
Chris Z. Radziminski ◽  
Michael Lepuil ◽  
Robin Creason ◽  
Robert C. Andrews
Keyword(s):  
Chlorine Dioxide ◽  
Most Probable Number ◽  
Inactivation Kinetics ◽  
Clostridium Sporogenes ◽  
Probable Number ◽  
Waterborne Pathogen ◽  
Viability Assay ◽  
The Relationship ◽  
Different Sources

ABSTRACT Cryptosporidium parvum, which is resistant to chlorine concentrations typically used in water treatment, is recognized as a significant waterborne pathogen. Recent studies have demonstrated that chlorine dioxide is a more efficient disinfectant than free chlorine against Cryptosporidium oocysts. It is not known, however, if oocysts from different suppliers are equally sensitive to chlorine dioxide. This study used both a most-probable-number–cell culture infectivity assay and in vitro excystation to evaluate chlorine dioxide inactivation kinetics in laboratory water at pH 8 and 21�C. The two viability methods produced significantly different results (P < 0.05). Products of disinfectant concentration and contact time (Ct values) of 1,000 mg � min/liter were needed to inactivate approximately 0.5 log10 and 2.0 log10 units (99% inactivation) of C. parvumas measured by in vitro excystation and cell infectivity, respectively, suggesting that excystation is not an adequate viability assay. Purified oocysts originating from three different suppliers were evaluated and showed marked differences with respect to their resistance to inactivation when using chlorine dioxide.Ct values of 75, 550, and 1,000 mg � min/liter were required to achieve approximately 2.0 log10 units of inactivation with oocysts from different sources. Finally, the study compared the relationship between easily measured indicators, includingBacillus subtilis (aerobic) spores andClostridium sporogenes (anaerobic) spores, and C. parvum oocysts. The bacterial spores were found to be more sensitive to chlorine dioxide than C. parvum oocysts and therefore could not be used as direct indicators of C. parvum inactivation for this disinfectant. In conclusion, it is suggested that future studies address issues such as oocyst purification protocols and the genetic diversity of C. parvum, since these factors might affect oocyst disinfection sensitivity.

scholarly journals Mutants of Mycobacterium tuberculosis Lacking Three of the Five rpf-Like Genes Are Defective for Growth In Vivo and for Resuscitation In Vitro

2005 ◽  
Vol 73 (5) ◽  
pp. 3038-3043 ◽  
Author(s):  
Katrina J. Downing ◽  
Vladimir V. Mischenko ◽  
Margarita O. Shleeva ◽  
Danielle I. Young ◽  
Michael Young ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Micrococcus Luteus ◽  
Most Probable Number ◽  
Infection Model ◽  
Term Survival ◽  
Probable Number ◽  
Mouse Infection Model ◽  
Nonculturable State

ABSTRACT Mycobacterium tuberculosis contains five genes, rpfA through rpfE, that bear significant homology to the resuscitation-promoting factor (rpf) gene of Micrococcus luteus, whose product is required to resuscitate the growth of dormant cultures of M. luteus and is essential for the growth of this organism. Previous studies have shown that deletion of any one of the five rpf-like genes did not affect the growth or survival of M. tuberculosis in vitro. In conjunction with the results of whole-genome expression profiling, this finding was indicative of their functional redundancy. In this study, we demonstrate that the single deletion mutants are phenotypically similar to wild-type M. tuberculosis H37Rv in vivo. The deletion of individual rpf-like genes had no discernible effect on the growth or long-term survival of M. tuberculosis in liquid culture, and the ability to resuscitate spontaneously from a nonculturable state in a most probable number assay was also unaffected for the three strains tested (the ΔrpfB, ΔrpfD, and ΔrpfE strains). In contrast, two multiple strains, KDT8 (ΔrpfA-mutation ΔrpfC ΔrpfB) and KDT9 (ΔrpfA ΔrpfC ΔrpfD), which lack three of the five rpf-like genes, were significantly yet differentially attenuated in a mouse infection model. These mutants were also unable to resuscitate spontaneously in vitro, demonstrating the importance of the Rpf-like proteins of M. tuberculosis in resuscitation from the nonculturable state. These results strongly suggest that the biological functions of the five rpf-like genes of M. tuberculosis are not wholly redundant and underscore the potential utility of these proteins as targets for therapeutic intervention.

scholarly journals In vivo efficacy of carvacrol on Campylobacter jejuni prevalence in broiler chickens during an entire fattening period

2020 ◽  
Vol 10 (3) ◽  
pp. 131-138
Author(s):  
V. Szott ◽  
B. Reichelt ◽  
T. Alter ◽  
A. Friese ◽  
U. Roesler
Keyword(s):  
Essential Oils ◽  
Campylobacter Jejuni ◽  
Broiler Chickens ◽  
Most Probable Number ◽  
Resistant Bacteria ◽  
Probable Number ◽  
Plant Essential Oils ◽  
Fattening Period

AbstractCarvacrol, a primary constituent of plant essential oils (EOs), and its antimicrobial activity have been the subject of many in vitro studies. Due to an increasing demand for alternative antimicrobials and an emerging number of antibiotic resistant bacteria, the use of essential oils has played a major role in many recent approaches to reduce Campylobacter colonization in poultry before slaughter age. For that purpose, the reducing effect of carvacrol on Campylobacter jejuni prevalence in broilers was determined in vivo in an experimental broiler chicken model during an entire fattening period. Carvacrol was added to the feed in a concentration of 120 mg/kg feed four days post hatch until the end of the trial. In this study, we demonstrated a statistically significant decrease of C. jejuni counts by 1.17 decadic logarithm (log10) most probable number (MPN)/g in cloacal swabs during starter and grower periods (corresponding to a broilers age between 1 and 28 days). Similar results were observed for colon enumeration at the end of the trial where C. jejuni counts were significantly reduced by 1.25 log10 MPN/g. However, carvacrol did not successfully reduce Campylobacter cecal colonization in 33-day-old broilers.

Bactericidal Effect of Sodium Chlorate on Escherichia coli O157:H7 and Salmonella Typhimurium DT104 in Rumen Contents In Vitro

2000 ◽  
Vol 63 (8) ◽  
pp. 1038-1042 ◽  
Author(s):  
ROBIN C. ANDERSON ◽  
SANDRA A. BUCKLEY ◽  
LEON F. KUBENA ◽  
LARRY H. STANKER ◽  
ROGER B. HARVEY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Salmonella Typhimurium ◽  
Bactericidal Effect ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Respiratory Nitrate Reductase

Escherichia coli O157:H7 and Salmonella Typhimurium DT104 are important foodborne pathogens affecting the beef and dairy industries and strategies are sought to rid these organisms from cattle at slaughter. Both pathogens possess respiratory nitrate reductase that also reduces chlorate to the lethal chlorite ion. Because most anaerobes lack respiratory nitrate reductase, we hypothesized that chlorate may selectively kill E. coli O157:H7 and Salmonella Typhimurium DT104 but not potentially beneficial anaerobes. In support of this hypothesis, we found that concentrations of E. coli O157:H7 and Salmonella Typhimurium DT104 were reduced from approximately 1,000,000 colony forming units (CFU) to below our level of detection (≤10 CFU) following in vitro incubation (24 h) in buffered ruminal contents (pH 6.8) containing 5 mM added chlorate. In contrast, chlorate had little effect on the most probable number (mean ± SD) of total culturable anaerobes (ranging from 9.9 ± 0.72 to 10.7 ± 0.01 log10 cells/ml). Thus, chlorate was bactericidal to E. coli O157:H7 and Salmonella Typhimurium DT104 but not to potentially beneficial bacteria. The bactericidal effect of chlorate was concentration dependent (less at 1.25 mM) and markedly affected by pH (more bactericidal at pH 6.8 than pH 5.6).

scholarly journals Plant Growth Response ofPinus patulaandP. maximinoiSeedlings at Nursery to Three Types of Ectomycorrhizal Inocula

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Manuel F. Restrepo-Llano ◽  
Nelson W. Osorio-Vega ◽  
Juan D. León-Peláez
Keyword(s):  
Plant Growth ◽  
Ectomycorrhizal Fungi ◽  
Root Colonization ◽  
Interactive Effects ◽  
Suillus Luteus ◽  
Potato Dextrose Agar Medium ◽  
P Content ◽  
Promote Plant Growth ◽  
Ectomycorrhizal Colonization

The objective of this study was to assess the response in seedling growth, root colonization, and P content of seedlings ofPinus maximinoiandP. patulato the inoculation with three types of ectomycorrhizal inocula with three doses (17.5, 35, and 70 kg·m−3) in nursery. The first inoculum was soil from aPinusplantations that contained three ectomycorrhizal fungi (Amanita muscaria, Amanitasp.,andSuillus luteus); the second was a crude inoculum composed by root fragments ofPinusseedlings colonized byS. luteussuspended in a sterile matrix soil-sand; the third inoculum was a mixture of two ectomycorrhizal fungiA. muscariaandS. luteusproduced underin vitroconditions in the potato-dextrose-agar medium. The results showed that the inoculum producedin vitrowas most effective to promote plant growth and ectomycorrhizal colonization of roots in both plant species. Also, the effects on seedlings were significantly higher with the increase of the doses. InP. patulathere were not significant effects on foliar P content with type and dose of inocula, whereas inP. maximinoithere were interactive effects of both factors. In this case, better results were obtained with the inoculum produced underin vitroconditions and with the highest dose.

Inactivation of Cryptosporidium parvum Oocysts in Cider by Flash Pasteurization

2001 ◽  
Vol 64 (4) ◽  
pp. 523-527 ◽  
Author(s):  
MING QI DENG ◽  
DEAN O. CLIVER
Keyword(s):  
Cryptosporidium Parvum ◽  
Fluorescent Antibody ◽  
Most Probable Number ◽  
Probable Number ◽  
Log Reduction ◽  
Antibody Staining ◽  
Heat Treated ◽  
Infected Cells ◽  
Medical Importance

Cryptosporidium parvum is a well-recognized pathogen of significant medical importance, and cider (apple juice) has been associated with foodborne cryptosporidiosis. This study investigated the effect of flash pasteurization on the viability of contaminant C. parvum oocysts. Cider inoculated with oocysts was heated at 70 or 71.7°C for 5, 10, or 20 s, and oocyst viability was measured by a semiquantitative in vitro infectivity assay. By infecting multiple wells of confluent Madin-Darby bovine kidney cells with serial dilutions of heat-treated oocysts and examining infected cells by indirect fluorescent antibody staining, the most probable number technique was applied to quantify log reduction of oocyst viability. Heating for 10 or 20 s at either temperature caused oocyst killing of at least 4.9 log (or 99.999%), whereas oocyst inactivation after pasteurization for 5 s at 70 and 71.7°C was 3.0 log (99.9%) and 4.8 log (99.998%), respectively. Our results suggested that current practices of flash pasteurization in the juice industry are sufficient in inactivating contaminant oocysts.

Effect of Organic Acids and Hydrogen Peroxide on Cryptosporidium parvum Viability in Fruit Juices

2003 ◽  
Vol 66 (9) ◽  
pp. 1650-1657 ◽  
Author(s):  
KALMIA E. KNIEL ◽  
SUSAN S. SUMNER ◽  
DAVID S. LINDSAY ◽  
CAMERON R. HACKNEY ◽  
MERLE D. PIERSON ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Culture ◽  
Organic Acids ◽  
Cryptosporidium Parvum ◽  
Most Probable Number ◽  
Oocyst Wall ◽  
Probable Number ◽  
Apple Cider ◽  
Infectivity Assay

Cryptosporidium parvum has historically been associated with waterborne outbreaks of diarrheal illness. Foodborne cryptosporidiosis has been associated with unpasteurized apple cider. Infectious oocysts are shed in the feces of common ruminants like cattle and deer in and near orchards. In this study, the ability of organic acids and hydrogen peroxide (H2O2) added to fruit juice to inhibit the survival of C. parvum was analyzed. Oocyst viability was analyzed by a cell culture infectivity assay with the use of a human ileocecal cell line (HCT-8) whose infectivity pattern is similar to that for human oral infectivity. Cell monolayers were infected with 106 treated oocysts or a series of 10-fold dilutions. Parasitic life stages were visualized through immunohistochemistry with 100 microscope fields per monolayer being counted. In vitro excystation assays were also used to evaluate these treatments. Organic acids and H2O2 were added to apple cider, orange juice, and grape juices on a weight/volume basis. Malic, citric, and tartaric acids at concentrations of 1 to 5% inhibited C. parvum's infectivity of HCT-8 cells by up to 88%. Concentrations ranging from 0.025 to 3% H2O2 were evaluated. The addition of 0.025% H2O2 to each juice resulted in a &gt;5-log reduction of C. parvum infectivity as determined with a most-probable-number–based cell culture infectivity assay. As observed with differential interference contrast and scanning electron microscopy, reduced infectivity may be mediated through effects on the oocyst wall that are caused by the action of H2O2 or related oxygen radicals. The addition of low concentrations of H2O2 can represent a valuable alternative to pasteurization.

Analysis of Coliform and Colifecal Total Pollution Test on Various Types of Drinking Water Using the MPN (Most Probable Number) Method

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Wanda Aulya ◽  
Fadhliani Fadhliani ◽  
Vivi Mardina
Keyword(s):  
Drinking Water ◽  
Fecal Coliform ◽  
Pathogenic Bacteria ◽  
Microbiological Quality ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Inspection Method ◽  
Sample Number ◽  
Probable Number ◽  
Fecal Coliform Bacteria

Water is the main source for life and also the most severe substance caused by pollution. The mandatory parameters for determining microbiological quality of drinking water are total non-fecal Coliform bacteria and Coliform fecal (Escherichia coli). Coliform bacteria are a group of microorganisms commonly used as indicators, where these bacteria can be a signal to determine whether a water source has been contaminated by bacteria or not, while fecal Coliform bacteria are indicator bacteria polluting pathogenic bacteria originating from human feces and warm-blooded animals (mammals) . The water inspection method in this study uses the MPN (Most Probable Number) method which consists of 3 tests, namely, the presumption test, the affirmation test, and the reinforcement test. The results showed that of 15 drinking water samples 8 samples were tested positive for Coliform bacteria with the highest total bacterial value of sample number 1, 15 (210/100 ml), while 7 other samples were negative. From 8 positive Coliform samples only 1 sample was stated to be negative fecal Coliform bacteria and 7 other samples were positive for Coliform fecal bacteria with the highest total bacterial value of sample number 1 (210/100 ml).

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