Disinfection of selected Aspergillus spp. using ultraviolet germicidal irradiation

2004 ◽  
Vol 50 (3) ◽  
pp. 221-224 ◽  
Author(s):  
Christopher F Green ◽  
Pasquale V Scarpino ◽  
Paul Jensen ◽  
Nancy J Jensen ◽  
Shawn G Gibbs

Aims: The efficacy of ultraviolet germicidal irradiation (UVGI) and the UVGI dose necessary to inactivate fungal spores on an agar surface for cultures of Aspergillus flavus and Aspergillus fumigatus were determined. Methods and results: A four-chambered UVGI testing unit with a 9-W, Phillips, low pressure, mercury UVGI lamp in each chamber was used in this study. An aperture was adjusted to provide 50, 100, 150, and 200 µW/cm2 of uniform flux to the surfaces of the Petri dish, resulting in a total UVGI dose to the surface of the Petri dishes ranging from 12 to 96 mJ/cm2. The UVGI dose necessary to inactivate 90% of the A. flavus and A. fumigatus was 35 and 54 mJ/cm2, respectively. Conclusions: UVGI can be used to inactivate culturable fungal spores. Aspergillus flavus was more susceptible than A. fumigatus to UVGI. Significance and impact of the study: These results may not be directly correlated to the effect of UVGI on airborne fungal spores, but they indicate that current technology may not be efficacious as a supplement to ventilation unless it can provide higher doses of UVGI to kill spores traveling through the irradiated zone.Key words: Aspergillus, ultraviolet germicidal irradiation, fungi.

2005 ◽  
Vol 51 (9) ◽  
pp. 801-804 ◽  
Author(s):  
Christopher F Green ◽  
Craig S Davidson ◽  
Pasquale V Scarpino ◽  
Shawn G Gibbs

The ultraviolet germicidal irradiation (UVGI) dose necessary to inactivate fungal spores on an agar surface and the efficacy of UVGI were determined for cultures of Stachybotrys chartarum (ATCC 208877). This study employed a UVGI testing unit consisting of four chambers with a 9-W, Phillips, low pressure, mercury UVGI lamp in each chamber. The testing unit's apertures were adjusted to provide 50, 100, 150, and 200 µW/cm2 of uniform flux to the Petri dish surfaces, resulting in a total UVGI surface dose ranging from 12 to 144 mJ/cm2. The UVGI dose necessary to inactivate 90% of the S. chartarum was greater than the maximum dose of 144 mJ/cm2 evaluated in this study. While UVGI has been used to inactivate several strains of culturable fungal spores, S. chartarum was not susceptible to an appropriate dose of UVGI. The results of this study may not correlate directly to the effect of UVGI on airborne fungal spores. However, they indicate that current technology may not be efficacious as a supplement to ventilation unless it can provide higher doses of UVGI to kill spores, such as S. chartarum, traveling through the irradiated zone.Key words: Stachybotrys chartarum (synonyms S. atra, S. alternana), ultraviolet germicidal irradiation, fungi.


1974 ◽  
Vol 4 (3) ◽  
pp. 301-307 ◽  
Author(s):  
H. H. Ünligil ◽  
M. S. H. Shih ◽  
J. K. Shields

Airborne fungal spores were trapped at three lumber storage locations in the lower Ottawa Valley by exposing petri dishes containing malt agar medium. The fungal colonies developing were counted and identified. Highest counts from morning exposures were obtained at Braeside in June, at Ottawa in July, and at Thurso in September. Afternoon exposures, made only in Ottawa, yielded generally higher counts than morning exposures. While dark colonies predominated at Ottawa and Braeside sites, where mainly softwood lumber was stored, hyaline and white colonies prevailed at the hardwood lumber yard at Thurso. The three most common fungi at the Ottawa and Braeside locations were Alternaria spp., Aureobasidiumpullulons, and Penicillium spp. At the Thurso site, Alternaria spp., Trichodermaviride, and Penicilliumspp. were most numerous. A Cladosporium sp., a Graphium sp., and an Alternaria sp., caused considerable staining on the surface of white birch blocks in laboratory tests.


1995 ◽  
Vol 20 (1) ◽  
pp. 329-329
Author(s):  
E. Guerrero-Rodriguez ◽  
S. Davalos-Luna ◽  
J. Corrales-Reynaga

Abstract Populations of MCR of commercial field corn from Arenal, Jalisco were exposed to nine insecticides of organophosphorous (OP), cabamate, organo chlorinated and pyrethroid groups. Larvae were collected from the roots of corn plants daily, and confined in polyethylene black bags of two kg capacity with humidity and germinated corn as food for larvae. Insects were taken to the laboratory of Sanidad Vegetal in Guadalajara, Jalisco. Dilutions of the insecticides tested were prepared using acetone from 500 to 5000 ppm (6 to 9 dosage/product). For this study 20 larvae of last instar were selected and 1 u, liter of the solution was placed topically on the thorax, after this, each larva was placed in a petri dish with a moistened paper towel and the petri dishes confined in a cardboard box to eliminate light. Mortality counts were carried out at 24 hours. Percent mortality was corrected by Abbott’s formula. The mortality data were analyzed by probit to obtain LC50 and LC,5 values for each insecticide.


Aerobiologia ◽  
2004 ◽  
Vol 20 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Padmanabhan S. Jothish ◽  
Themath Soman Nayar

1998 ◽  
Vol 23 (1) ◽  
pp. 372-372
Author(s):  
Nihat Demirel ◽  
Whitney Cranshaw

Abstract Trials were conducted with adult, field collected migratory grasshoppers to determine susceptibility to ingestion expo sure to Beauveria bassiana Strain GHA (BotaniGard WP), spinosad (Conserve SC) a garlic-derived insecticide/repellent (Garlic Barrier), neem oil (Tril ogy) and a neem extract (BioNeem). Field collected late instar grasshoppers were confined, 8 per petri dish (100 mm X 15 mm), with 6 petri dishes usetl per treatment. Treatments involved dipping alfalfa leaves into the insecticide solutions and allowing them to air dry before feeding these to the grasshop pers. After the originally treated foliage were consumed, untreated foliage was used to maintain grasshoppers in all treatments. Mortality was assessed a 24, 48, 96, and 192 h after exposure.


Author(s):  
سعاد محمد خليفة أبوالغيث ◽  
أحلام القمودي محمد زعيط

استهدفت هذه الدراسة عزل بعض أنواع الفطريات من التربة الملوثة بالهيدروكربون بمصفاة الزاوية لتكرير النفط، حيث تم عزل وتعريف بعض الفطريات مثل Rhizopus, Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, Aspergillus nidulans وأوضحت نتائج هذه الدراسة أن تواجد وتنوع فطر Aspergillus قد تفوق معنويا مقارنة بتواجد وتنوع فطرRhizopus. كما تم في هذه الدراسة اختبار قدرة وكفاءة الفطريات المعزولة على النمو واستغلال المركبات الهيدروكربونية المتمثلة في زيت الحمادة وزيت الشرارة بتركيز 1% و3%، حيث أوضحت النتائج بأن جنس Rhizopus سجل أعلى معدل للنمو على الوسط الغذائي Malt Extract Agar، وسجل كلا من فطر A. fumigatus وفطر A. flavus معدّل النمو القطري أعلى معنويا من النمو القطري لفطرA. niger  وفطر A. nidulans. هذه المعدّلات العالية تدل على إمكانية استخدام الفطريات المعزولة في المعالجة البيولوجية للتربة الملوّثة بالنفط.


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