The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
Gediminas Mainelis - One of the best experts on this subject based on the ideXlab platform.
-
development and calibration of real time pcr for quantification of Airborne Microorganisms in air samples
Atmospheric Environment, 2006Co-Authors: Hey Reoun An, Gediminas Mainelis, Lori A WhiteAbstract:Abstract This manuscript describes the coupling of bioaerosol collection and the use of real-time PCR (RT-PCR) to quantify the Airborne bacteria. The quantity of collected bacteria determined by RT-PCR is compared with conventional quantification techniques, such as culturing, microscopy and Airborne Microorganism counting by using optical particle counter (OPC). Our data show that an experimental approach used to develop standard curves for use with RT-PCR is critical for accurate sample quantification. Using universal primers we generated 12 different standard curves which were used to quantify model organism Escherichia coli (Migula) Catellani from air samples. Standard curves prepared using a traditional approach, where serially diluted genomic DNA extracted from pure cultured bacteria were used in PCR reaction as a template DNA yielded significant underestimation of sample quantities compared to Airborne Microorganism concentration as measured by an OPC. The underestimation was especially pronounced when standard curves were built using colony forming units (CFUs). In contrast, the estimate of cell concentration in an air sample by RT-PCR was more accurate (∼60% compared to the Airborne Microorganism concentration) when the standard curve was built using aerosolized E. coli. The accuracy improved even further (∼100%) when air samples used to build the standard curves were diluted first, then the DNA extracted from each dilution was amplified by the RT-PCR—to mimic the handling of air samples with unknown and possibly low concentration. Therefore, our data show that standard curves used for quantification by RT-PCR needs to be prepared using the same environmental matrix and procedures as handling of the environmental sample in question. Reliance on the standard curves generated with cultured bacterial suspension (a traditional approach) may lead to substantial underestimation of Microorganism quantities in environmental samples.
-
utilization of natural electrical charges on Airborne Microorganisms for their collection by electrostatic means
Journal of Aerosol Science, 2006Co-Authors: Gediminas MainelisAbstract:Abstract Bioaerosol exposure assessment requires effective Airborne Microorganism collection methods. This research investigates whether the natural electrical charges on Airborne Microorganisms can be utilized for their collection by electrostatic means. To test this hypothesis, a new sampling device (Electrosampler), which deposits Airborne Microorganisms onto agar collection medium by electrostatic means, was designed and built. Different from traditional electrostatic precipitators, this device features no charging of incoming particles. The performance of the new sampler when collecting culturable bacteria and fungi in indoor and outdoor environments was compared against a traditional microbial impactor operated in parallel. The testing was performed for three different collection flow rates (1.2, 5, and 10 L/min) at a fixed electrostatic field strength of 5 kV/cm inside the collection chamber. For all testing conditions, the Electrosampler recovered more Airborne Microorganisms than the impactor with a difference as large as 5–9 times under certain conditions. The obtained data indicate that utilization of natural Microorganism charge and electrostatic collection technique may provide a bioaerosol sampling method with higher recovery of culturable Airborne Microorganisms compared to inertia-based techniques.
-
utilization of natural electrical charges on Airborne Microorganisms for their collection by electrostatic means
Journal of Aerosol Science, 2006Co-Authors: Gediminas MainelisAbstract:Abstract Bioaerosol exposure assessment requires effective Airborne Microorganism collection methods. This research investigates whether the natural electrical charges on Airborne Microorganisms can be utilized for their collection by electrostatic means. To test this hypothesis, a new sampling device (Electrosampler), which deposits Airborne Microorganisms onto agar collection medium by electrostatic means, was designed and built. Different from traditional electrostatic precipitators, this device features no charging of incoming particles. The performance of the new sampler when collecting culturable bacteria and fungi in indoor and outdoor environments was compared against a traditional microbial impactor operated in parallel. The testing was performed for three different collection flow rates (1.2, 5, and 10 L/min) at a fixed electrostatic field strength of 5 kV/cm inside the collection chamber. For all testing conditions, the Electrosampler recovered more Airborne Microorganisms than the impactor with a difference as large as 5–9 times under certain conditions. The obtained data indicate that utilization of natural Microorganism charge and electrostatic collection technique may provide a bioaerosol sampling method with higher recovery of culturable Airborne Microorganisms compared to inertia-based techniques.
-
Development and calibration of real-time PCR for quantification of Airborne Microorganisms in air samples
Atmospheric Environment, 2006Co-Authors: Gediminas Mainelis, Lori A WhiteAbstract:This manuscript describes the coupling of bioaerosol collection and the use of real-time PCR (RT-PCR) to quantify the Airborne bacteria. The quantity of collected bacteria determined by RT-PCR is compared with conventional quantification techniques, such as culturing, microscopy and Airborne Microorganism counting by using optical particle counter (OPC). Our data show that an experimental approach used to develop standard curves for use with RT-PCR is critical for accurate sample quantification. Using universal primers we generated 12 different standard curves which were used to quantify model organism Escherichia coli (Migula) Catellani from air samples. Standard curves prepared using a traditional approach, where serially diluted genomic DNA extracted from pure cultured bacteria were used in PCR reaction as a template DNA yielded significant underestimation of sample quantities compared to Airborne Microorganism concentration as measured by an OPC. The underestimation was especially pronounced when standard curves were built using colony forming units (CFUs). In contrast, the estimate of cell concentration in an air sample by RT-PCR was more accurate (� 60% compared to the Airborne Microorganism concentration) when the standard curve was built using aerosolized E. coli. The accuracy improved even further (� 100%) when air samples used to build the standard curves were diluted first, then the DNA extracted from each dilution was amplified by the RT-PCR—to mimic the handling of air samples with unknown and possibly low concentration. Therefore, our data show that standard curves used for quantification by RT-PCR needs to be prepared using the same environmental matrix and procedures as handling of the environmental sample in question. Reliance on the standard curves generated with cultured bacterial suspension (a traditional approach) may lead to substantial underestimation of Microorganism quantities in environmental samples. r 2006 Elsevier Ltd. All rights reserved.
-
Airborne Microorganism collection by a new electrostatic precipitator
2002Co-Authors: Klaus Willeke, Gediminas Mainelis, S Lee, Atin Adhikari, Tiina Reponen, Sergey A Grinshpun, S H Cho, Mikhaylo TrunovAbstract:Many aerobiological measurements and the protection of governmental/military establishments from bioterrorism require the development of new bioaerosol collectors that can be operated efficiently at low power. We have developed and evaluated a new bioaerosol sampler in which the Microorganisms are collected by electrostatic means. An ionizer charges the incoming Microorganisms, if they carry insufficient charge for efficient collection in the device. The Microorganisms are collected on two square agar plates placed along the flow axis. Laboratory experiments have shown that bacterial cells and spores are generally collected more efficiently than inert particles. We attribute this difference to the natural negative charge contained in the cell membranes of Microorganisms. The results of field measurements parallel those obtained through laboratory experiments.
Lori A White - One of the best experts on this subject based on the ideXlab platform.
-
development and calibration of real time pcr for quantification of Airborne Microorganisms in air samples
Atmospheric Environment, 2006Co-Authors: Hey Reoun An, Gediminas Mainelis, Lori A WhiteAbstract:Abstract This manuscript describes the coupling of bioaerosol collection and the use of real-time PCR (RT-PCR) to quantify the Airborne bacteria. The quantity of collected bacteria determined by RT-PCR is compared with conventional quantification techniques, such as culturing, microscopy and Airborne Microorganism counting by using optical particle counter (OPC). Our data show that an experimental approach used to develop standard curves for use with RT-PCR is critical for accurate sample quantification. Using universal primers we generated 12 different standard curves which were used to quantify model organism Escherichia coli (Migula) Catellani from air samples. Standard curves prepared using a traditional approach, where serially diluted genomic DNA extracted from pure cultured bacteria were used in PCR reaction as a template DNA yielded significant underestimation of sample quantities compared to Airborne Microorganism concentration as measured by an OPC. The underestimation was especially pronounced when standard curves were built using colony forming units (CFUs). In contrast, the estimate of cell concentration in an air sample by RT-PCR was more accurate (∼60% compared to the Airborne Microorganism concentration) when the standard curve was built using aerosolized E. coli. The accuracy improved even further (∼100%) when air samples used to build the standard curves were diluted first, then the DNA extracted from each dilution was amplified by the RT-PCR—to mimic the handling of air samples with unknown and possibly low concentration. Therefore, our data show that standard curves used for quantification by RT-PCR needs to be prepared using the same environmental matrix and procedures as handling of the environmental sample in question. Reliance on the standard curves generated with cultured bacterial suspension (a traditional approach) may lead to substantial underestimation of Microorganism quantities in environmental samples.
-
Development and calibration of real-time PCR for quantification of Airborne Microorganisms in air samples
Atmospheric Environment, 2006Co-Authors: Gediminas Mainelis, Lori A WhiteAbstract:This manuscript describes the coupling of bioaerosol collection and the use of real-time PCR (RT-PCR) to quantify the Airborne bacteria. The quantity of collected bacteria determined by RT-PCR is compared with conventional quantification techniques, such as culturing, microscopy and Airborne Microorganism counting by using optical particle counter (OPC). Our data show that an experimental approach used to develop standard curves for use with RT-PCR is critical for accurate sample quantification. Using universal primers we generated 12 different standard curves which were used to quantify model organism Escherichia coli (Migula) Catellani from air samples. Standard curves prepared using a traditional approach, where serially diluted genomic DNA extracted from pure cultured bacteria were used in PCR reaction as a template DNA yielded significant underestimation of sample quantities compared to Airborne Microorganism concentration as measured by an OPC. The underestimation was especially pronounced when standard curves were built using colony forming units (CFUs). In contrast, the estimate of cell concentration in an air sample by RT-PCR was more accurate (� 60% compared to the Airborne Microorganism concentration) when the standard curve was built using aerosolized E. coli. The accuracy improved even further (� 100%) when air samples used to build the standard curves were diluted first, then the DNA extracted from each dilution was amplified by the RT-PCR—to mimic the handling of air samples with unknown and possibly low concentration. Therefore, our data show that standard curves used for quantification by RT-PCR needs to be prepared using the same environmental matrix and procedures as handling of the environmental sample in question. Reliance on the standard curves generated with cultured bacterial suspension (a traditional approach) may lead to substantial underestimation of Microorganism quantities in environmental samples. r 2006 Elsevier Ltd. All rights reserved.
Helene Niculitahirzel - One of the best experts on this subject based on the ideXlab platform.
-
assessment of Airborne Microorganisms by real time pcr optimistic findings and research challenges
Frontiers in Bioscience, 2011Co-Authors: Anne Oppliger, Frederic G Masclaux, Helene NiculitahirzelAbstract:: Most Airborne Microorganisms are natural components of our ecosystem. Soil, vegetation and animals, including humans, are sources for aerial release of these living or dead cells. In the past, assessment of Airborne Microorganisms was mainly restricted to occupational health concerns. Indeed, in several occupations, exposure to very high concentrations of non-infectious Airborne bacteria and fungi, result in allergenic, toxic or irritant reactions. Recently, the threat of bioterrorism and pandemics have highlighted the urgent need to increase knowledge of bioaerosol ecology. More fundamentally, Airborne bacterial and fungal communities begin to draw much more consideration from environmental microbiologists, who have neglected this area for a long time. This increased interest of scientists is to a great part due to the development and use of real-time PCR techniques to identify and quantify Airborne Microorganisms. Even if the advantages of the PCR technology are obvious, researchers are confronted with new problems. This review describes the methodological state of the art in bioaerosols field and emphasizes the future challenges and perspectives of the real-time PCR-based methods for Airborne Microorganism studies.
Claudia Cafarchia - One of the best experts on this subject based on the ideXlab platform.
-
cryptococcus neoformans in the respiratory tract of squirrels callosciurus finlaysonii rodentia sciuridae
Medical Mycology, 2015Co-Authors: Roberta Iatta, Davide Immediato, Maria Rita Puttilli, Patrizia Danesi, Giuseppe Passantino, Antonio Parisi, Egidio Mallia, Domenico Otranto, Claudia CafarchiaAbstract:Cryptococcosis is a fungal disease acquired from the environment, for which animals may serve as sentinels for human exposure. The occurrence of Cryptococcus spp. in the respiratory tract of 125 squirrels, Callosciurus finlaysonii, trapped in Southern Italy, was assessed. Upon examination of nasal swabs and lung tissue from each individual, a total of 13 (10.4%) animals scored positive for yeasts, 7 for Cryptococcus neoformans (C.n.) (5.6%) and 6 for other yeasts (4.8%). C.n. was isolated from the nostrils and lungs, with a high population size in nostrils. Two C.n. molecular types, VNI and VNIV, were identified, with C.n. var. grubii VNI the most prevalent. Phylogenetic analyses of ITS+ and URA5 sequences revealed that C.n. isolates were genetically similar to isolates from a range of geographical areas and hosts. Results suggest that C.n. can colonize or infect the respiratory tract of C. finlaysonii. The high occurrence and level of colonization of nasal cavities might be an indicator of environmental exposure to high levels of Airborne Microorganism. The close phylogenetic relationship of C.n. strains from squirrels with those from human and other animal hosts suggests a potential role for these animals as “sentinels” for human exposure.
Anne Oppliger - One of the best experts on this subject based on the ideXlab platform.
-
assessment of Airborne Microorganisms by real time pcr optimistic findings and research challenges
Frontiers in Bioscience, 2011Co-Authors: Anne Oppliger, Frederic G Masclaux, Helene NiculitahirzelAbstract:: Most Airborne Microorganisms are natural components of our ecosystem. Soil, vegetation and animals, including humans, are sources for aerial release of these living or dead cells. In the past, assessment of Airborne Microorganisms was mainly restricted to occupational health concerns. Indeed, in several occupations, exposure to very high concentrations of non-infectious Airborne bacteria and fungi, result in allergenic, toxic or irritant reactions. Recently, the threat of bioterrorism and pandemics have highlighted the urgent need to increase knowledge of bioaerosol ecology. More fundamentally, Airborne bacterial and fungal communities begin to draw much more consideration from environmental microbiologists, who have neglected this area for a long time. This increased interest of scientists is to a great part due to the development and use of real-time PCR techniques to identify and quantify Airborne Microorganisms. Even if the advantages of the PCR technology are obvious, researchers are confronted with new problems. This review describes the methodological state of the art in bioaerosols field and emphasizes the future challenges and perspectives of the real-time PCR-based methods for Airborne Microorganism studies.
