Sporicidal Action of Hydrogen Peroxide on Conidia From Toxigenic Strains of Aspergillus flavus and Aspergillus parasiticus

1977 ◽  
Vol 40 (9) ◽  
pp. 617-621 ◽  
Author(s):  
SHELLEY Y. BUCHEN ◽  
E. H. MARTH
Keyword(s):  
Hydrogen Peroxide ◽  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
The Other ◽  
Spore Concentration ◽  
Survival Curves ◽  
Toxigenic Strains ◽  
Time Required ◽  
Logarithmic Reduction

Effectiveness of hydrogen peroxide was evaluated as a sporicidal agent aginst conidia of Aspergillus parasiticus NRRL 2999 and 3315, and Aspergillus flavus NRRL 3353. Conidia were harvested from 7-, 10-, and 14-day-old mold cultures grown on modified Moyer's agar, treated with hydrogen peroxide, and then were recovered with mycological agar. An initial spore concentration of 5 × 105 to 1 × 106 per ml was treated with 2, 4, and 6% (wt/vol) peroxide at 40, 30, and 20 C. Survival curves were not straight logarithmic but tended to tail off at the end. Time required for 99.9% reduction of spores ranged from minutes to an hour, and on rare occasions it took hours to achieve the first logarithmic reduction. Conidia of NRRL 3353 consistently were most resistant among the three strains tested. Conidia of NRRL 2999 and 3315 were equally sensitive to peroxide in most instances, although time required for 99.9% destruction of the latter was occasionally greater. Conidia from 14-, and 10-day-old cultures of NRRL 3315 and 3353, respectively, were more resistant than conidia from the other mold cultures. Resistance of conidia from NRRL 2999 was not affected by age of the culture.

Sporicidal Action of Hydrogen Peroxide on Conidia From Toxigenic Strains of Aspergillus flavus and Aspergillus parasiticus

1977 ◽  
Vol 40 (10) ◽  
pp. 698-703 ◽  
Author(s):  
SHELLEY Y. BUCHEN ◽  
E. H. MARTH
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Chloride ◽  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Similar Response ◽  
Initial Value ◽  
Effects Of Ph ◽  
Spore Population ◽  
Toxigenic Strains ◽  
Strain Dependent

Effects of pH, sucrose, glucose, and sodium chloride on resistance of 14-day-old conidiospores of Aspergillus parasiticus NRRL 2999 and 3315, and Aspergillus flavus NRRL 3353 to a solution of 6% hydrogen peroxide at 20 C were determined. An increase in time necessary to attain 99.9% destruction of spores resulted when the pH of hydrogen peroxide was adjusted from an initial value of 3.79 to 6.40 and 8.30. However, the amount of the increase was strain-dependent and was directly related to resistance of spores to peroxide. Addition of 10 to 40% sucrose or 3 to 10% sodium chloride to the menstruum caused either an increase or decrease in the time needed to destroy 99.9% of the spore population, depending on the amount of additive that was used. Spores were more difficult to inactivate by peroxide in the presence rather than absence of sucrose or salt, but protection afforded by the additives diminished when their concentration was great. Addition of 10 to 30% glucose elicited a similar response only from spores produced by the most resistant of the three strains tested, whereas resistance of spores from the other strains was not markedly affected.

Effect of Butylated Hydroxyanisole on Conidial Germination of Toxigenic Species of Aspergillus flavus and Aspergillus parasiticus

1991 ◽  
Vol 54 (5) ◽  
pp. 375-377 ◽  
Author(s):  
D.P. THOMPSON
Keyword(s):  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Conidial Germination ◽  
Potato Dextrose Agar ◽  
The Other ◽  
Butylated Hydroxyanisole ◽  
Other Hand ◽  
Inhibition Zones ◽  
Toxigenic Strains ◽  
Fungitoxic Effect

The fungitoxic effect of butylated hydroxyanisole (BHA) on germination of conidia from seven toxigenic strains of Aspergillus was examined on potato dextrose agar (PDA). At concentrations of 200 μg/ml and above, BHA prevented germination of conidia in all of the test fungi after 24 and 48 h of incubation. On the other hand, at 100 μg/ml BHA reduced the rate of germination. When an impregnated disk assay was employed, distinct inhibition zones were observed at 200, 400, 800, and 1000 μg/disk of BHA after 24 h of incubation. After 48 h of incubation, distinct inhibition zones were still observed at 800 and 1000 μg/disk.

Proteolytic and Lipolytic Activities of some Toxigenic and Nontoxigenic Aspergilli and Penicillia

1980 ◽  
Vol 43 (5) ◽  
pp. 354-355 ◽  
Author(s):  
S. M. EL-GENDY ◽  
E. H. MARTH
Keyword(s):  
Proteolytic Activity ◽  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Lipolytic Activity ◽  
The Other ◽  
Aspergillus Ochraceus ◽  
Penicillium Roqueforti ◽  
Two Cultures ◽  
Penicillium Cyclopium ◽  
Penicillium Patulum

Eighteen strains of Aspergillus flavus or Aspergillus parasiticus, one of Aspergillus ochraceus and 12 strains or species of Penicillium, many of them isolated from cheese, were evaluated for their proteolytic and lipolytic activities. Strains of A. flavus exhibited considerable proteolytic and little lipolytic activity, whereas the reverse was true for strains of A. parasiticus. Of the Penicillium cultures tested, 10 exhibited considerable lipolytic activity, but only five had marked proteolytic activity. Two cultures, Penicillium patulum M59, and Penicillium cyclopium No. 8, were markedly lipolytic and proteolytic. Of the other cultures, greatest lipolytic activity was associated with Penicillium roqueforti 849, Penicillium puberulum No. 33, A. parasiticus NRRL 3145 and NRRL 465 and A. ochraceus NRRL 3174, whereas greatest proteolytic activity of all the cultures was associated with P. patulum M59, P. cyclopium No. 25 and A. flavus WB500, 4018, 4098 and NRRL 5565.

Aflatoxigenic fungi and aflatoxin B1 in commercial pet food in Brazil

2009 ◽  
Vol 2 (1) ◽  
pp. 85-90 ◽  
Author(s):  
S. Campos ◽  
L. Keller ◽  
L. Cavaglieri ◽  
C. Krüger ◽  
M. Fernández Juri ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Aspergillus Parasiticus ◽  
Storage Conditions ◽  
Pet Food ◽  
Dog Food ◽  
Aflatoxigenic Fungi ◽  
Toxigenic Strains ◽  
Aflatoxin B ◽  
Prevalent Species ◽  
Recommended Level

The aims of this study were to determine the aflatoxigenic mycoflora and the incidence of aflatoxin B1 in commercial samples of ready dog food. This in turn demonstrated the ability of the Aspergillus flavus and Aspergillus parasiticus strains to produce aflatoxin B1. 180 samples (standard, premium and super premium) were collected. Aspergillus was the prevalent genera followed by Penicillium and Fusarium. A. flavus and A. parasiticus were the prevalent species. All A. flavus and A. parasiticus strains from super premium samples were able to produce aflatoxin B1, whereas toxigenic strains isolated from standard and premium samples varied from 80 to 100%. A high percentage of ready pet food contaminated by toxigenic species from section Flavi was found and aflatoxin B1 levels were detected. The fungal counts from the three kinds of feed did not exceed the proposed value (1×104 cfu/g) and none of the samples exceeded the aflatoxin B1 recommended level (20 ng/g). The presence of A. flavus and A. parasiticus with aflatoxigenic ability could be a potential risk for production of AFB1 in feedstuffs when environmental storage conditions are not adequate.

Toxigenic and Nontoxigenic Strains of Aspergilli and Penicillia Grown in the Presence of Sodium Chloride Cause Enzyme-Catalyzed Hydrolysis of Protein, Fat and Hydrogen Peroxide

1986 ◽  
Vol 49 (1) ◽  
pp. 29-32 ◽  
Author(s):  
FATHY E. EL-GAZZAR ◽  
ELMER H. MARTH
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Chloride ◽  
Aspergillus Flavus ◽  
Peroxidase Activity ◽  
Aspergillus Parasiticus ◽  
Lipolytic Activity ◽  
Aspergillus Ochraceus ◽  
Hydrolysis Of ◽  
Penicillium Spp

Eight strains of Aspergillus flavus, three of Aspergillus parasiticus, one of Aspergillus ochraceus and ten of Penicillum spp. were evaluated for their ability to hydrolyze protein, fat and hydrogen peroxide when the molds were grown in the presence of different amounts (0–10%) of sodium chloride. Proteolytic and lipolytic activities of strains of A. flavus generally increased with an increase in the amount of sodium chloride in the medium. This was true for proteolytic and less so for lipolytic activity of A. parasiticus and A. ochraceus. Of the penicillia tested, five exhibited a marked increase and five a smaller increase in proteolytic and lipolytic activity at 2, 4 and 6% sodium chloride, but such activity either remained constant or decreased at 8 and 10% sodium chloride. Peroxidase activity in mycelia of all strains of aspergilli increased with an increase of sodium chloride in the medium. Most strains of Penicillium spp. exhibited maximum peroxidase activity at 2% sodium chloride, and some reduction in activity when the amount of sodium chloride in the medium exceeded 2%.

Intrafungal distribution of aflatoxins among conidia and sclerotia of Aspergillus flavus and Aspergillus parasiticus

1983 ◽  
Vol 29 (1) ◽  
pp. 1-5 ◽  
Author(s):  
D. T. Wicklow ◽  
O. L. Shotwell
Keyword(s):  
At Risk ◽  
Chemical Defense ◽  
Aspergillus Flavus ◽  
Evolutionary Theory ◽  
Aspergillus Parasiticus ◽  
Total Aflatoxin ◽  
Defense Systems ◽  
Large Numbers ◽  
Toxigenic Strains ◽  
Aflatoxin B

This research examines the distribution of aflatoxins among conidia and sclerotia of toxigenic strains of Aspergillus flavus Link and Aspergillus parasiticus Speare cultured on Czapek agar (21 days, 28 °C). Total aflatoxin levels in conidia and sclerotia varied considerably both within (intrafungal) and among strains. Aspergillus flavus NRRL 6554 accumulated the highest levels of aflatoxin (conidia: B1 84 000 ppb; G1; 566 000 ppb; sclerotia: B1, 135 000 ppb; G1, 968 000 ppb). Substantial aflatoxin levels in conidia could place at risk those agricultural workers exposed to dust containing large numbers of A. flavus conidia. Cellular ratios of aflatoxin B1 to aflatoxin G1 were nearly identical in conidia and sclerotia even though levels of total aflatoxins in these propagule types may have differed greatly. Aflatoxin G1 was detected in sclerotia of all A. flavus strains but in the conidia of only one strain. Each of the A. parasiticus strains examined accumulated aflatoxin G1 in both sclerotia and conidia. These results are examined in the context of current evolutionary theory predicting an increase in the chemical defense systems of fungal sclerotia, propagules critical to the survival of these organisms.

Understanding the risks and rewards of using 50% vs. 10% strength peroxide in pulp bleach plants

TAPPI Journal ◽  
2018 ◽  
Vol 17 (11) ◽  
pp. 601-607
Author(s):  
Alan Rudie ◽  
Peter Hart
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Rate ◽  
The Other ◽  
Mechanical Pulp ◽  
Engineering Controls ◽  
Point Of Use ◽  
Process Failure

The use of 50% concentration and 10% concentration hydrogen peroxide were evaluated for chemical and mechanical pulp bleach plants at storage and at point of use. Several dangerous occurrences have been documented when the supply of 50% peroxide going into the pulping process was not stopped during a process failure. Startup conditions and leaking block valves during maintenance outages have also contributed to explosions. Although hazardous events have occurred, 50% peroxide can be stored safely with proper precautions and engineering controls. For point of use in a chemical bleach plant, it is recommended to dilute the peroxide to 10% prior to application, because risk does not outweigh the benefit. For point of use in a mechanical bleach plant, it is recommended to use 50% peroxide going into a bleach liquor mixing system that includes the other chemicals used to maintain the brightening reaction rate. When 50% peroxide is used, it is critical that proper engineering controls are used to mitigate any risks.

Pengaruh Luka Iris Pada Tikus Dengan Paparan Hidrogen Peroxida 3% terhadap Epitelisasi dan Pembentukan Eksudat pada Permukaan Epitel Kulit.

2020 ◽  
Vol 17 (2) ◽  
pp. 172
Author(s):  
HARMAN AGUSAPUTRA ◽  
MARIA SUGENG ◽  
AYLY SOEKAMTO ◽  
ATIK WULANDARI
Keyword(s):  
Hydrogen Peroxide ◽  
Wound Healing ◽  
The Other ◽  
Delayed Wound Healing ◽  
Peroxide Group ◽  
Hemostatic Effect ◽  
Significant Difference ◽  
Negative Effect ◽  
Wound Healing Effect ◽  
Epithelial Growth

<p><strong>Abstract</strong></p><p><strong>Background:</strong> Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) as antiseptic has been used frequently to clean woundsin in hospitals and clinics. Hydrogen peroxide has the effectof strong oxidative that can kill pathogens. It can clean up debris and necrotic tissuesin wounds. Hydrogen peroxidealso has hemostatic effect that can help to stop bleeding. Besides antiseptic effects, hydrogen peroxide i s suspected of having negative effect in wound healing. Hydrogen peroxide presumably could cause delayed wound healing by exudate formation and delayed epithelial growth.</p><p><strong>Method</strong>: This study was conducted in the laboratory using 48 white mice that were divided into 2 groups. All the mice were purposely wounded. Afterwards in one group the wounds were clean up using hydrogen peroxide, while in the other group without hydrogen peroxide as control. The wounds of both groups were observed on day 1, day 3 and day 7. On day 1 and day 3, both groups did not show significant difference.</p><p><strong>R</strong><strong>esult</strong> : on day 7 showed that the wound healing in hydrogen peroxide group were delayed. Fifty percent of them had the formation of exudate and 62.5% of them showed delayed epithelial growth.</p><p><strong>Conclusion </strong>: This study could show hydrogen peroxide as wound antiseptic has delayed wound healing effect.</p><p><strong>Keyword</strong>: hydrogen peroxide, wound healing</p>

Antimicrobial Effect of 940 nm Diode Laser based on Photolysis of Hydrogen Peroxide in the Treatment of Periodontal Disease

2018 ◽  
Vol 69 (8) ◽  
pp. 2081-2088 ◽  
Author(s):  
Alin Alexandru Odor ◽  
Edwin Sever Bechir ◽  
Deborah Violant ◽  
Victoria Badea
Keyword(s):  
Hydrogen Peroxide ◽  
Laser Therapy ◽  
Diode Laser ◽  
Antimicrobial Effect ◽  
The Other ◽  
Control Group ◽  
Group 4 ◽  
Periodontal Bacteria ◽  
Severe Periodontitis ◽  
Before And After

Moderate and severe periodontitis represents a challenge in the non-surgical periodontal therapy. Due to the lack of evidence regarding the antimicrobial effectiveness of 940 nm diode laser in periodontal treatment, this study aimed to evaluate the antimicrobial effect of hydrogen peroxide (H2O2) photolysis performed with 940 nm diode laser in the treatment of moderate and severe periodontitis. Twenty-five patients with 100 teeth were selected for this pilot study. The test teeth were randomly assigned to one of the four treatment groups: Group 1: scaling and root planning (SRP) (control group); and the following experimental groups: Group 2: H2O2; Group 3: 940 nm diode laser therapy; Group 4: 940 nm diode laser therapy and H2O2. Clinical examinations, like probing depth (PD), clinical attachment level (CAL) and bleeding on probing (BOP) were performed before and after the treatment. The microbiological evaluation, effectuated before and after the treatment, included nine periodontal bacteria species and investigated by means of real-time PCR assay. The clinical and bacterial differences in the tested groups, was assessed between control group and the other three experimental groups, as well as between the experimental groups. The total bacteria load was reduced for all four studied groups. Group 4 (diode laser + H2O2) showed significant bacterial reduction of the major periodontal bacteria like Pg., Tf., Td., Pi., Pm., Fn (p[0.001) than the other 3 groups (p]0.001). Also the periodontal clinical parameters, like PD, CAL and BOP showed a significant reduction after the photolysis of H2O2 with the 940 nm diode laser (p[0.001). Differences between tested groups showed a significant beneficial results in regard to Group 4.It is suggested that the photoactivation of H2O2 with the 940 nm diode laser can be used successfully in adjunctive to the non-surgical periodontal treatment as a bactericidal tool.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

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