Concentration Of Biological Particles Research Articles

Characterization of culturable airborne microorganisms in the Yucatan Peninsula

The concentration of biological particles in the atmosphere is widely variable because it depends on several meteorological and geographical factors. Meteorological conditions in tropical coastal cities are unique due to both marine and terrestrial influences that can strongly modify the concentration and diversity of airborne microorganisms. Nevertheless, very few studies have been conducted in tropical coastal cities.This study presents the comparative results from four field campaigns carried out between 2017 and 2018 in two tropical cities located in the Yucatan Peninsula (Mexico): Sisal (a village right on the coast) and Merida (the State capital, 48 km from the coastline). The concentration of bacteria and fungal propagules, in colony-forming units or CFU per m3, sampled in Merida and Sisal are not comparable despite their proximity (i.e., 48 km away); however, both show similar seasonality and inter-annual trends. The results indicate that terrestrial microbiota dominates over that of marine origin, and show that fungal propagules are the dominant microorganism present at both sites. Also, these results indicate that meteorological conditions in the rainy season are more favorable for the growth of microorganisms than dry cold conditions.The predominant culturable bacterial phylum sampled during the four field campaigns carried out in 2017 and 2018 in the Yucatan Peninsula were Actinobacteria, Firmicutes, and Proteobacteria. The fraction of bacteria that reacted to a Gram positive stain was 62% and to Gram negative 38%. The fungal propagules genera relative concentration varied between both sampling sites, with Cladosporium and Penicillium being the most common at the coast in Sisal and Aspergillus in Merida.

Accurate measurement of airborne biological particle concentration based on laser-induced fluorescence technique

We develop a biological particle counter based on laser-induced fluorescence for accurate measurement of biological particle concentrations in the air. Pure water, NaCl particles, polystyrene latex spheres, and standard fluorescent particles are used as media to evaluate the performance of the counter. Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa are used as representative biological particles to evaluate the measurement accuracy of the counter. In experiments, the results measured by the counter are consistent with he results obtained with the culture method; For each bacterium, good linear agreement is observed between the two results, and the values of the coefficient R2 are all more than 0.97. Because of particle superposition errors, system error, etc., at low concentrations, the number measured by the counter divided by the number measured by the culture method, η = Ncounter/Nculture, is larger than that at high concentrations. For same type of test sample, although the distribution is different, the η values at same concentrations are similar. Finally, the repeatability of the two methods is tested. The results obtained using the counter are found to be more stable, with a relative standard deviation (RSD) of 8.14%; this is less than the RSD of 15% obtained using the culture method.

Impact of Gusty Northwesterly Winds on Biological Particles in Winter in Beijing

Biological aerosol particles play a crucial role in cloud formation and succession of ecosystems and have a large impact on human health. However, the variations in the concentration, composition, and viability of biological particles remain unclear. This study, conducted in January 2013 and January 2015 in Beijing, explores the influence of meteorological conditions on the variations in the concentration and composition of biological particles. Concentrations of biological particles were measured by an online optical detector, waveband integrated bioaerosol sensor (WIBS-4A). The composition of bacterial communities within biological particles was measured by 16S rDNA sequencing. The results showed that the number concentration of biological particles ranged from 2 L-1 to 150 L-1 during winter. The wind could largely influence the concentration and composition of biological particles. During gusty northwesterly winds, when wind speed was above 4 m·s-1 and wind direction was from the northwest (~30°), the concentration increased by one order of magnitude, and the composition of bacterial communities sharply changed. After the passage of gusty winds, the composition gradually changed back to its prior state.

A cantilever biosensor based on a gap method for detecting Escherichia coli in real time

Dynamic-mode cantilever biosensors are an attractive technology for measuring the presence or concentration of biological particles in a sample, but their performance is severely reduced in liquid due to damping. A few techniques have emerged to overcome damping, including the use of millimeter-sized cantilevers and suspended microchannel resonators. Here we present a newly discovered technique to overcome damping and obtain strong responses in liquid. E. coli cells are collected in a micron-sized gap at the free end of a cantilever using electrokinetic effects and they are measured in real time using the frequency shift of the fundamental resonant frequency of the cantilever. The effect of gap size, cantilever usage, and electrokinetic voltage are analyzed. Measurements are performed without surface functionalization, flow, or a frequency tracking circuit using samples with concentrations as low as 100cells/ml.

Microbial cell budgets of anArctic glacier surface quantified using flow cytometry

Uncertainty surrounds estimates of microbial cell and organic detritus fluxes from glacier surfaces. Here, we present the first enumeration of biological particles draining from a supraglacial catchment, on Midtre Lovénbreen (Svalbard) over 36 days. A stream cell flux of 1.08 × 10(7) cells m(-2) h(-1) was found, with strong inverse, non-linear associations between water discharge and biological particle concentrations. Over the study period, a significant decrease in cell-like particles exhibiting 530 nm autofluorescence was noted. The observed total fluvial export of ~7.5 × 10(14) cells equates to 15.1-72.7 g C, and a large proportion of these cells were small (< 0.5 μm in diameter). Differences between the observed fluvial export and inputs from ice-melt and aeolian deposition were marked: results indicate an apparent storage rate of 8.83 × 10(7) cells m(-2) h(-1). Analysis of surface ice cores revealed cell concentrations comparable to previous studies (6 × 10(4) cells ml(-1)) but, critically, showed no variation with depth in the uppermost 1 m. The physical retention and growth of particulates at glacier surfaces has two implications: to contribute to ice mass thinning through feedbacks altering surface albedo, and to potentially seed recently deglaciated terrain with cells, genes and labile organic matter. This highlights the merit of further study into glacier surface hydraulics and biological processes.

Size-selective assessment of airborne particles in swine confinement building with the UVAPS

The Ultraviolet Aerodynamic Particle Sizer (UVAPS) is a novel aerosol counter for realtime monitoring of viable bioaerosols. The previous validation studies on the UVAPS were either laboratory based or were conducted outdoor with the artificially generated aerosols. In this study, the spectrometer was applied to investigate particulate pollution inside a swine confinement building (SCB). Real-time capabilities of the instrument were used to investigate the effect of on-farm-activities, such as an effluent flushing with recycled water, on microbial load inside the SCB. In addition to the UVAPS, monitoring of viable bioaerosols (bacteria and fungi) was simultaneously conducted with the sixstage Andersen microbial impactor and the AGI-30 impingers. The UVAPS measurements showed that the concentrations of both total and biological particles inside the SCB were in order of 106 -107 particles/ m3. These concentrations were approximately seven times the outside concentrations for total particles and up to 12 times for biological particles. Approximately 95 % of both total and biological particles were respirable (< 7mm) and approximately 60 % of total and 50 % of biological particles accounted for the fine particle fraction (<2.5 mm). The concentration of biological particles measured with the UVAPS was at least one order of magnitude higher than the concentration of the viable microorganisms measured with the AGI-30 impingers. Nevertheless, the trends in the concentration changes of bioaerosols measured with the UVAPS followed the trends in the concentration changes of the airborne microorganisms quite adequately. Thus, it was concluded that the UVAPS is an appropriate method for investigating the dynamic of bioaerosols in the SCBs. The results obtained in this study assist in advancing an understanding of the UVAPS performance in the real-life agricultural settings. In addition, the data provide a new insight on the particles size distribution inside the SCB, depending on their nature.

The size distribution of primary biological aerosol particles in cloud water on the mountain Kleiner Feldberg/Taunus (FRG)

During the field campaign, FELDEX 95 cloud water samples were collected and the insoluble particles were analysed by single particle analysis in order to determine the content of primary biological aerosol particles (PBAP). It is found that 25% of the total insoluble particles are biological ones. During cloud events with increasing wind velocity, the concentration of biological particles also increases. Anthropogenic influence leads to a higher amount of both total and biological particles. Within the size distribution, the percentage of biological particles decreases with increasing radius.

Real-time warning of biological-agent attacks with the Canadian Integrated Biochemical Agent Detection System II (CIBADS II)

The Gulf War highlighted the growing threat of military use of chemical and biological (CB) weapons. Since that time revelations about the size and scope of the offensive CB agent programs in the former Soviet Union, Iraq, and other nations have confirmed this assessment. Further, terrorist threats and incidents throughout the world in recent years have shown that there is a growing potential for the civilian use of CB weapons. Many countries have undertaken programs to develop improved defenses against CB agent use, focusing on more effective detection systems as the key to providing advanced warning of an attack or mitigating the effectiveness of an attack. Requirements for detection systems include real-time detection to provide warning in time to avoid exposure, near-real-time identification to identify agents in time to treat casualties, and collection of samples for independent verification of use to validate any response. The Canadian Integrated Biochemical Agent Detection System (CIBADS II) is the first system to combine reliable real-time detection with low support requirements and automated operation to enhance ease of deployment. A key element of the CIBADS II is the fluorescence aerodynamic particle sizer (FLAPS), which can distinguish particles that contain live organisms from most other respirable particles in air. The follow-on version of CIBADS II, called 4WARN, enhances the advantages of CIBADS II through the development of more effective alarm algorithms while reducing the size, weight, and power requirements of the system. The present article will summarize the results of over 100 releases of simulants at four sets of field trials (Dugway Proving Ground, Utah, and the Defence Research Establishment Suffield, Canada) where CIBADS II has reliably detected concentrations of simulants below 10 agent-containing particles per liter of air (ACPLA), with low false-alarm rates. It is able to discriminate releases of biological aerosols from normal background aerosols with the use of an automated alarm algorithm with an average response time of 15 s, and can avoid false alarms from fluctuations in background aerosol concentrations due to natural occurrences such as forest fires and human activity such as trucks passing by on the test site. In addition, data from the FLAPS provide previously unobtainable environmental information on the live biological content and variability in background aerosols. Our studies suggest that the background concentrations of biological particles at the sites tested can vary by over an order of magnitude, but are relatively constant as a proportion of the total background particles. These scientific data will be discussed in detail, as will the potential for use of CIBADS II and its components in the study of airborne biological organisms. © 1999 John Wiley & Sons, Inc. Field Analyt Chem Technol 3: 260–273, 1999

High gradient magnetic separation of a biologically produced FeS adsorbent using sulphate reducing bacteria

A High Gradient Magnetic Separation (HGMS) technique has been used to selectively recover biologically produced iron sulphide (FeS) particles with adsorbed heavy metal ions, from a soil remediation effluent stream. The HGMS system has been optimised and its performance investigated as a function of the magnetic field, flow rate and concentration of biological particles, with time. Results have shown that an efficiency of over 95% can be obtained, proving that HGMS is a valuable method for the concentration of heavy metal contaminated soils, especially when the adsorbed heavy metals are toxic and difficult to handle by other means.

Evidence for long range transport of biological and anthropogenic aerosol particles in the atmosphere

Abstract A program aimed at making measurements principally of biological particles (pollen, spores, bacteria) at the ground and aloft over an extended grassland region, was performed in the neighborhood of Miles City, Montana, during the period of operation of Project CCOPE a large multiinstitutional field study of the characteristics of convective storms. Project CCOPE offered a large framework of measurements of atmospheric parameters useful for the interpretation of measured concentrations of biological particles and their behavior in height and time. The measurements carried out are being studied in relation to air trajectories, air mass changes, and the known distribution of sources of detected particles. Analysis of filter samples performed between ground level and 6000 m height revealed significant concentrations of biological particles at all heights, and some interesting observations of transport of non-biological particles emitted by a coal-fired power plant to at least 6000 m. Some meteorological explanations of the observations are offered.

Vertical profiles of biological particle concentrations under convective conditions

Measurements of vertical profiles of pollen concentration from local and remote sources have been made during convective conditions with balloon-mounted rotating impaction samplers.