PubMed · 7493577
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F Daschner. 1995-12-01. [Humidifiers].. https://pubmed.ncbi.nlm.nih.gov/7493577/
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Airborne dispersal enables plant pathogens to travel across fields, regions, and continents, fueling rapid epidemics and emerging disease threats. Biosurveillance, the systematic monitoring of airborne inoculum, offers the opportunity to detect pathogens before symptoms appear and informs timely, risk-based management. Recent advances in air sampling, molecular diagnostics, metagenomics, and imaging technologies have expanded the scale and resolution of pathogen monitoring, from single-species qPCR assays to community-level aerobiome surveys. Integration of biosurveillance data with decision-support systems, remote sensing, and artificial intelligence is transforming early-warning capabilities and providing novel insights into pathogen ecology, evolution, and fungicide resistance. Yet major challenges remain, including assay standardization, data interpretation, and translation into actionable tools for growers. This review synthesizes current approaches, highlights case studies in which biosurveillance has advanced disease management, and outlines future directions toward coordinated surveillance networks and precision agriculture applications.
A method is described for the quantitation of muramic acid, a marker of bacterial peptidoglycan, in organic dust. House dust samples were hydrolysed in hydrochloric acid and then extracted with hexane to remove hydrophobic compounds. The aqueous phase was evaporated, heated in a silylation reagent to form trimethylsilyl derivatives, and analysed by gas chromatography--mass spectrometry. The muramic acid derivative gave two peaks upon injection into the gas chromatograph--mass spectrometer. Injection of 10 pg of the derivative gave a signal-to-noise ratio of 17 for the dominating peak when using selected ion monitoring in the electron impact mode, and a linear calibration curve was achieved upon analysis of samples containing 5-1500 ng of muramic acid. In a house dust sample, 40 ng of muramic acid was found per mg of dust; the coefficient of variation was 8.2% (n = 6, 1.2 mg of dust analysed). The described method is rapid and simple to apply, and should therefore become widely used for measuring peptidoglycan in many types of environmental samples, including organic dust.
Paired air and water samples were collected at Resolute Bay (74 degrees N, 95 degrees W) in summer 1992 to estimate the direction of gas exchange of hexachlorocyclohexanes (HCHs) and investigate possible loss processes in the water column. Average concentrations of alpha-HCH and gamma-HCH in ocean surface water were 4.7 +/- 0.9 and 0.44 +/- 0.11 ng/l, respectively. These alpha- and gamma-HCH levels are approximately 66-104% and 54-72% of values reported for the central Arctic Ocean at the Canadian Ice Island in 1986. Mean atmospheric concentrations of alpha-HCH and gamma-HCH (114 +/- 16 and 9.8 +/- 1.3 pg/m3) were 2-3 times lower than summer Arctic levels in the 1980s. The ocean surface water (-1.4 degrees C) was approximately within Henry's Law equilibrium with respect to atmospheric gamma-HCH levels. Water/air fugacity ratios were 1.03 for gamma-HCH and 1.57 for alpha-HCH, indicating a slight potential for volatilization of alpha-HCH. The two alpha-HCH enantiomers in air and water were separated by chromatography on a gamma-cyclodextrin capillary column. The enantiomeric ratio (ER = ratio of (+)alpha-HCH/(-)alpha-HCH) in air was 1.00 +/- 0.04. This agrees excellently with ER = 1.00 +/- 0.01 found for a racemic alpha-HCH standard. The (+) enantiomer was depleted in seawater, resulting in ER = 0.93 +/- 0.06 in Resolute Bay. ERs of samples from Amituk Lake on Cornwallis Island ranged from 0.65 to 0.99, depending on location, date and relative contributions of fresh snowmelt and older lake water. These results suggest that microbial degradation of HCHs is taking place in Arctic lakes and near-shore marine waters.