scholarly journals Use of the aqueous extract of Eucalyptus microcorys for the treatment in microcosm, of water containing Enterococcus faecalis: hierarchisation of cells' inhibition factors

2018 ◽  
Vol 1 (1) ◽  
pp. 47-56
Author(s):  
Tamsa Arfao Antoine ◽  
Lontsi Djimeli Chretien ◽  
Noah Ewoti Olive Vivien ◽  
Moussa Djaouda ◽  
Yaouba Aoudou ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Aqueous Extract ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Extract Concentration ◽  
Light Intensities ◽  
Incubation Periods ◽  
Incubation Duration ◽  
Major Factors ◽  
Aquatic Microcosm

Abstract An experimental study in aquatic microcosm was carried out to determine the major factors involved in the inhibition of Enterococcus faecalis in the presence of aqueous extract of Eucalyptus microcorys. The planktonic bacterial cells remained in various concentrations of the aqueous solution at light intensities which fluctuated between 0 and 3,000 lx and incubation periods which ranged from 3 to 24 hours. A hierarchisation of studied factors revealed that the aqueous extract concentration, followed by experimental temperature, light intensity and incubation duration influence the inhibition of E. faecalis cells, respectively, with a rate of 86.82%, 7.03%, 5.25% and 0.90%. The cell abundances dropped significantly at 1.5% (λ = 0.491 and F = 5.518) and 2% (λ = 0.568 and F = 4.055) concentrations coupled with 1,000, 2,000 and 3,000 lx. The highest light intensities and extract concentration produce the highest log removal values. The disinfectant properties of E. microcorys were evaluated by the Chick–Watson model. This Chick–Watson model so obtained varied between log (N/No) = −0.09 Ct and log (N/No) = −0.17 Ct for extract concentrations of 1, 1.5 and 2%. Aqueous extract of E. microcorys could be used for water disinfection.

Water disinfection using photo-Fenton: Effect of temperature on Enterococcus faecalis survival

2012 ◽  
Vol 46 (18) ◽  
pp. 6154-6162 ◽  
Author(s):  
E. Ortega-Gómez ◽  
P. Fernández-Ibáñez ◽  
M.M. Ballesteros Martín ◽  
M.I. Polo-López ◽  
B. Esteban García ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Water Disinfection ◽  
Effect Of Temperature

scholarly journals Impact of two disinfectants on detachment of Enterococcus faecalis from polythene in aquatic microcosm

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
C. Lontsi Djimeli ◽  
A. Tamsa Arfao ◽  
V Rossi ◽  
N Nsulem ◽  
V Raspal ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Adhesion ◽  
Enterococcus Faecalis ◽  
Sodium Hypochlorite ◽  
Growth Phases ◽  
Planktonic Cells ◽  
Stationary Growth ◽  
Experimental Conditions ◽  
The Impact ◽  
Aquatic Microcosm

<p><strong>After cell adhesion processes in microcosm, the impact of sodium hypochlorite (NaOCl) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) on the detachment of <em>Enterococcus faecalis </em>from polythene fragments immersed in water under stationary and dynamic conditions was assessed. The abundance of planktonic cells was also evaluated. The density of <em>E. faecalis</em> adhered in absence of disinfectant fluctuated between 2 and 4 units (Log CFU/cm<sup>2</sup>). </strong><strong>After living in disinfected water, </strong><strong>the density of <em>E. faecalis</em> remained adhered to polythene sometimes reached 2 units (Log CFU/Cm<sup>2</sup>)</strong><strong>. </strong><strong>This highest abundance of cells remained adhered was recorded with cells coming from the lag, exponential and stationary growth phases in water treated with 0.5‰ NaOCl. In H<sub>2</sub>O<sub>2</sub> disinfected water, the highest value was recorded at all cells growth phases with 5‰ H<sub>2</sub>O<sub>2 </sub>concentration. Adhered <em>E. faecalis</em> cells have been sometimes completely or partially decimated respectively by NaOCl and H<sub>2</sub>O<sub>2</sub> treated water. Considering separately each experimental condition, it was noted that increasing the concentration of disinfectant caused a significant decrease (P≤0.01) in abundance of cells stay adhered after living in water disinfected by the two disinfectants. Changes in disinfectant concentrations in different experimental conditions had an impact on the detachment of <em>E. faecalis</em> cells from the substrates. </strong></p>

scholarly journals Water disinfection under the helium influence

2021 ◽  
Vol 4 (3(60)) ◽  
pp. 6-8
Author(s):  
Iryna Koval
Keyword(s):  
Natural Waters ◽  
Unit Volume ◽  
Aqueous Media ◽  
Reaction Medium ◽  
Research Process ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Treatment Technology ◽  
Running Water ◽  
Number Of Microorganisms

The object of research is the process of water disinfection at the influence of gas from bacteria of a particular genus with different amounts per unit volume of water. Due to the annual increase in the amount of pollutants in natural waters, new opportunities to improve microbiological indicators of water quality are being explored. There are many different ways to disinfect it, both physical and chemical. However, no single method has been found to purify aqueous media from microorganisms that would ensure their effective destruction. It is proposed to study the activity of specific microorganisms during the bubbling of inert gas through the aqueous medium. The microorganisms studied were rod-shaped sporogenic cells of Bacillus cereus bacteria type. The test gas was inert helium. The study used continuous gas bubbling throughout the process, which allowed to mix microbial water efficiently and prevent the formation of stagnant zones in the reaction medium. In particular, active gas mixing facilitates its access to each cell. The gas supply rate corresponded to 0.2 cm3/s, and its flow rate was 0.7 dm3 for one hour of bubbling through microbial water. The duration of the entire research process was 7200 s. The constant temperature of the microbial water (T=288±1 K) was maintained during the experiment by cooling the glass reactor with running water. An in-depth method of culturing bacterial cells was used. A decrease in the number of microorganisms was observed throughout the helium supply process, despite the different initial amounts in the water. The highest destruction degree of bacillus (77.06 %) was obtained at the lowest studied concentration in water (NM01=3.4·104 CFU/cm3). This is due to the fact that less microbial load provides better conditions for access of helium to the cell and their effective destruction. The proposed method of water purification allowed to achieve a sufficiently high degree of water disinfection from sporogenic rod-shaped bacteria after the action of helium alone. In particular, it has been experimentally proven that the efficiency of the water disinfection process depends on the concentration of microorganisms per unit volume of water. Due to the treatment of contaminated water with gas, it is possible to obtain high rates of its purification and the application of this method for practical purposes in water treatment technology.

scholarly journals Allelopathic bioactivity of fresh and infused aqueous extracts of Brazilian cherry (Eugenia uniflora L.) on lettuce and maize

2018 ◽  
Vol 40 (1) ◽  
pp. 40972
Author(s):  
Nayara Parisoto Boiago ◽  
Andréa Maria Teixeira Fortes ◽  
Daiane Maria Pilatti ◽  
Paulo Sérgio Siberti da Silva
Keyword(s):  
Experimental Design ◽  
Aqueous Extract ◽  
Root Length ◽  
Germination Rate ◽  
Control Treatment ◽  
Aqueous Extracts ◽  
Initial Development ◽  
Extract Concentration ◽  
Time Index ◽  
Germination Speed

 This study aimed to analyse the allelopathic bioactivity of fresh and infused aqueous extracts of Brazilian cherry leaves on the germination of lettuce and the initial development of maize. Brazilian cherry leaves were used to prepare a fresh aqueous extract (200 g L-1) and an infused extract (100 g L-1), which were diluted to concentrations of 0.4, 0.8, 1.2, 1.6 or 2.0% w/v. The variables evaluated in lettuce were the germination rate (GR), germination time index (GTI), germination speed index (GSI) and root length (RL). To determine the effect on the initial development of maize, we measured the shoot (SL) and root (RL) length. The experimental design included a factorial 2 × 5 design (two extracts and five concentrations), in addition to a control treatment (no extract). In general, the allelopathic bioactivity differed between the fresh and infused extracts. The fresh extract was more phytotoxic for the GR and RL of lettuce. Some beneficial results were observed for the infused extract, including an increase in the RL of lettuce and SL of maize. These effects were dependent on the extract concentration. Thus, there is evidence that Brazilian cherry extracts have allelopathic bioactivity. 

Study of Reed Aqueous Extract’s Allelopathy on Alligator Weed

2012 ◽  
Vol 518-523 ◽  
pp. 5363-5365
Author(s):  
Guo Fu He ◽  
Juan Li ◽  
Wei Liu ◽  
Jing Li Du
Keyword(s):  
Aqueous Extract ◽  
Photosynthetic Pigment ◽  
Root Activity ◽  
Biochemical Mechanism ◽  
Alligator Weed ◽  
Water Culture ◽  
Extract Concentration ◽  
Pigment Contents ◽  
Mda Content ◽  
Physiological And Biochemical

In order to ascertain the allelopathy of Reed on Alligator Weed, the water culture experiments were performed to investigate the effects of aqueous extract on the growth, physiological and biochemical mechanism in Alligator Weed. The results showed that aqueous extract of Reed inhibited the growth of Alligator Weed, and the inhibition became stronger as the concentration of the extract increased. Some results from physiological and biochemical mechanism of treated Alligator Weed indicated that with the increase of extract concentration, photosynthetic pigment contents, root activity and CAT activity decreased, while P and MDA contents increased; N content decreased first and then up to normal. The results showed that aqueous extract of Reed inhibited the photosynthesis, CAT activities of Alligator Weed but increased the MDA content of Alligator Weed.

Embryonic Development, Early Growth, and Meristic Variation in Rainbow Trout (Salmo gairdneri) Exposed to Combinations of Light Intensity and Temperature

1975 ◽  
Vol 32 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Wen-hwa Kwain
Keyword(s):  
Rainbow Trout ◽  
Embryonic Development ◽  
Mortality Rates ◽  
Early Growth ◽  
Development Rate ◽  
Salmo Gairdneri ◽  
Initial Weight ◽  
Light Intensities ◽  
Incubation Periods ◽  
Meristic Variation

Lowest mortality rates of rainbow trout (Salmo gairdneri) embryos were obtained at temperatures of 7 and 10 C and light intensities of 0.2 and 20 lx. Temperatures of 3 and 15 C and an intensity of 400 lx were near the thresholds for development. Eggs exposed to 0.2 lx required 111 days to reach 50% hatch at 3 C, but 26 days at 15 C; those exposed to 20 lx, 97 days at 3 C and 25 days at 15 C.Growth rates of rainbow trout 145 days after hatch were significantly different (P < 0.05) at 10 and 3 C, and 20, 2, and 0.2 lx. The fastest growth occurred at 10 C and 2 lx, and the lowest growth at 3 C and 0.2 lx. For increment of body weight it was about 23.8%/day of initial weight and 6.6% at 3 C. At light intensities of 20, 2, and 0.2 lx, the rate per day was 24.7, 17.2, and 11.2%, respectively. However, increases in length occurred at a much reduced rate.Variations in numbers of vertebrae, gill rakers, and fin rays were positively correlated with the embryonic development rate. Longer incubation periods were usually associated with more meristic elements, regardless of the environmental factors involved.

scholarly journals Extracellular Electron Transfer Powers Enterococcus faecalis Biofilm Metabolism

2017 ◽  
Author(s):  
Damien Keogh ◽  
Ling Ning Lam ◽  
Lucinda E. Doyle ◽  
Artur Matysik ◽  
Shruti Pavagadhi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Enterococcus Faecalis ◽  
Bacterial Biofilm ◽  
Extracellular Electron Transfer ◽  
Bacterial Cells ◽  
Free Living ◽  
Biofilm Growth ◽  
Metabolic Versatility ◽  
Tract Infections ◽  
Biofilm Matrix

AbstractEnterococci are important human commensals and significant opportunistic pathogens associated with endocarditis, urinary tract infections, wound and surgical site infections, and medical device associated infections. These infections often become chronic upon the formation of biofilm. The biofilm matrix establishes properties that distinguish this state from free-living bacterial cells and increase tolerance to antimicrobial interventions. The metabolic versatility of the Enterococci is reflected in the diversity and complexity of environments and communities in which they thrive. Understanding metabolic factors governing colonization and persistence in different host niches can reveal factors influencing the transition from commensal to opportunistic pathogen. Here, we report a new form of iron-dependent metabolism for Enterococcus faecalis where, in the absence of heme, respiration components can be utilised for extracellular electron transfer (EET). Iron augments E. faecalis biofilm growth and generates alterations in biofilm matrix, cell spatial distribution, and biofilm matrix properties. We identify the genes involved in iron-augmented biofilm growth and show that it occurs by promoting EET to iron within biofilm.SignificanceBacterial metabolic versatility is often key in dictating the outcome of host-pathogen interactions, yet determinants of metabolic shifts are difficult to resolve. The bacterial biofilm matrix provides the structural and functional support that distinguishes this state from free-living bacterial cells. Here, we show that the biofilm matrix provides access to resources necessary for metabolism and growth which are otherwise inaccessible in the planktonic state. Our data shows that in the absence of heme, components of Enterococcus faecalis respiration (l-lactate dehydrogenase and acetaldehyde dehydrogenase) may function as initiators of EET through the cytoplasmic membrane quinone pool and utilize matrix-associated iron to carry out EET. The presence of iron resources within the biofilm matrix leads to enhanced biofilm growth.

scholarly journals Distribution of aminoglycoside resistance genes in recent clinical isolates of Enterococcus faecalis, Enterococcus faecium and Enterococcus avium

2001 ◽  
Vol 126 (2) ◽  
pp. 197-204 ◽  
Author(s):  
N. KOBAYASHI ◽  
MD. MAHBUB ALAM ◽  
Y. NISHIMOTO ◽  
S. URASAWA ◽  
N. UEHARA ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Clinical Isolates ◽  
University Hospital ◽  
Aminoglycoside Resistance ◽  
Genes Encoding ◽  
Enterococcal Species ◽  
Aminoglycoside Resistance Genes ◽  
Major Factors ◽  
High Level

Aminoglycoside modifying enzymes (AMEs) are major factors which confer aminoglycoside resistance on bacteria. Distribution of genes encoding seven AMEs was investigated by multiplex PCR for 279 recent clinical isolates of enterococci derived from a university hospital in Japan. The aac(6′)-aph(2″), which is related to high level gentamicin resistance, was detected at higher frequency in Enterococcus faecalis (42·5 %) than in Enterococcus faecium (4·3 %). Almost half of E. faecalis and E. faecium isolates possessed ant(6)-Ia and aph(3′)-IIIa. The profile of AME gene(s) detected most frequently in individual strains of E. faecalis was aac(6′)-aph(2″)+ant(6)-Ia+aph(3′)-IIIa, and isolates with this profile showed high level resistance to both gentamicin and streptomycin. In contrast, AME gene profiles of aac(6′)-Ii+ant(6)-Ia+aph(3′)-IIIa, followed by aac(6′)-Ii alone, were predominant in E. faecium. Only one AME gene profile of ant(6)-Ia+aph(3′)-IIIa was found in Enterococcus avium. The ant(4′)-Ia and ant(9)-Ia, which have been known to be distributed mostly among Staphylococcus aureus strains, were detected in a few enterococcal strains. An AME gene aph(2″)-Ic was not detected in any isolates of the three enterococcal species. These findings indicated a variety of distribution profiles of AME genes among enterococci in our study site.

scholarly journals A Novel Class of Lipoprotein Lipase-Sensitive Molecules Mediates Toll-Like Receptor 2 Activation by Porphyromonas gingivalis

2013 ◽  
Vol 81 (4) ◽  
pp. 1277-1286 ◽  
Author(s):  
Sumita Jain ◽  
Stephen R. Coats ◽  
Ana M. Chang ◽  
Richard P. Darveau
Keyword(s):  
Lipoprotein Lipase ◽  
Porphyromonas Gingivalis ◽  
Lipid A ◽  
Bacterial Cells ◽  
Toll Like Receptor ◽  
Two Phase ◽  
Content Type ◽  
Tlr2 Ligand ◽  
Toll Like Receptor 2 ◽  
Major Factors

ABSTRACTInfection by the chronic periodontitis-associated pathogenPorphyromonas gingivalisactivates a Toll-like receptor 2 (TLR2) response that triggers inflammation in the host but also promotes bacterial persistence. Our aim was to define ligands on the surfaces of intactP. gingivaliscells that determine its ability to activate TLR2. Molecules previously reported as TLR2 agonists include lipopolysaccharide (LPS), fimbriae, the lipoprotein PG1828, and phosphoceramides. We demonstrate that these molecules do not comprise the major factors responsible for stimulating TLR2 by whole bacterial cells. First,P. gingivalismutants devoid of the reported protein agonists, PG1828 and fimbriae, activate TLR2 as strongly as the wild type. Second, two-phase extraction of whole bacteria resulted in a preponderance of TLR2 agonist activity partitioning to the hydrophilic phase, demonstrating that phosphoceramides are not a major TLR2 ligand. Third, analysis of LPS revealed that TLR2 activation is independent of lipid A structural variants. Instead, activation of TLR2 and TLR2/TLR1 by LPS is in large part due to copurifying molecules that are sensitive to the action of the enzyme lipoprotein lipase. Strikingly, intactP. gingivalisbacterial cells treated with lipoprotein lipase were attenuated in their ability to activate TLR2. We propose that a novel class of molecules comprised by lipoproteins constitutes the major determinants that confer toP. gingivalisthe ability to stimulate TLR2 signaling.

scholarly journals A pulsed light system for the disinfection of flow through water in the presence of inorganic contaminants

2014 ◽  
Vol 13 (2) ◽  
pp. 406-412 ◽  
Author(s):  
Mary Garvey ◽  
Neil Rowan
Keyword(s):  
Uv Light ◽  
Water Disinfection ◽  
Bacterial Cells ◽  
Limited Data ◽  
Inorganic Contaminants ◽  
Test Species ◽  
Bacterial Endospores ◽  
Effective Form ◽  
Pulsed Uv Light ◽  
Flow Through

The use of ultraviolet (UV) light for water disinfection has become increasingly popular due to on-going issues with drinking water and public health. Pulsed UV light has proved to be an effective form of inactivating a range of pathogens including parasite species. However, there are limited data available on the use of pulsed UV light for the disinfection of flowing water in the absence or presence of inorganic contaminants commonly found in water sources. Here, we report on the inactivation of test species including Bacillus endospores following pulsed UV treatment as a flow through system. Significant levels of inactivation were obtained for both retention times tested. The presence of inorganic contaminants iron and/or manganese did affect the rate of disinfection, predominantly resulting in an increase in the levels of inactivation at certain UV doses. The findings of this study suggest that pulsed UV light may provide a method of water disinfection as it successfully inactivated bacterial cells and bacterial endospores in the absence and presence of inorganic contaminants.

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