Phytotechnologies have potential to reduce the amount or toxicity of deleterious chemicals and agents, and thereby, can reduce human exposures to hazardous substances. As such, phytotechnologies are tools for primary prevention in public health. Recent research demonstrates phytotechnologies can be uniquely tailored for effective exposure prevention in a variety of applications. In addition to exposure prevention, plants can be used as sensors to identify environmental contamination and potential exposures. In this paper, we have presented applications and research developments in a framework to illustrate how phytotechnologies can meet basic public health needs for access to clean water, air, and food. Because communities can often integrate plant-based technologies at minimal cost and with low infrastructure needs, the use of these technologies can be applied broadly to minimize potential contaminant exposure and improve environmental quality. These natural treatment systems also provide valuable ecosystem services to communities and society. In the future, integrating and coordinating phytotechnology activities with public health research will allow technology development focused on prevention of environmental exposures to toxic compounds. Hence, phytotechnologies may provide sustainable solutions to environmental exposure challenges, improving public health and potentially reducing the burden of disease.
Abstract:
A drop-collapse method has been refined for use as both a qualitative assay to screen for surfactant-producing microbes, and as a quantitative assay to determine surfactant concentration. The assay is rapid, easy to perform, reproducible and requires little specialized equipment. The assay is performed in a 96-microwell plate, where each well is thinly coated with oil. A 5 μL sample droplet is added to the center of a well and observed after 1 min. The droplet will either bead up, spread out slightly or collapse, depending on the amount of surfactant in the sample. The basis for this method is the type of oil used to coat each well. In the qualitative method, each well is coated with 1.8 μL of Pennzoil® and either the drop collapses, indicating the presence of surfactant (a positive result), or the drop remains beaded, indicating the absence of surfactant (a negative response). In the quantitative method, each well is coated with 2 μL of mineral oil, and a dissecting microscope is used to measure the diameter of the droplet at 1 min. Results with both a test biosurfactant (rhamnolipid) and a test synthetic surfactant (sodium dodecyl sulfate) indicate a direct linear correlation between droplet diameter and surfactant concentration. The drop-collapse method has several advantages over commonly used methods that measure surface tension, such as the du Nouy ring method; a smaller volume is required (5 μL vs. 20 mL), the effective range of measurement is greater and it does not require specialized equipment. Copyright (C) 1998 Elsevier Science B.V.
PMID: 1897987;Abstract:
The S-thiolated proteins phosphorylase b (Phb) and carbonic anhydrase III (CAIII) were prepared with [3H]glutathione in a reaction initiated with diamide. These substrates were used to measure the rate of reduction (dethiolation) of protein mixed-disulfides by enzymes with properties similar to those of thioredoxin and glutaredoxin. This enzyme activity is termed a dethiolase since the identities of the enzymes are still unknown. The dethiolation of either S-[3H]glutathiolated Phb or S-[3 H]glutathiolated CAIII was employed in tissue assays and for study of two partially purified dethiolases from cardiac tissue. NADPH-dependent dethiolase activity was most abundant except in rat liver and muscle. Total dethiolase activity was approximately 10-fold higher in neutrophils, 3T3-L1 cells, and Escherichia coli than in other sources. Rat skeletal muscle had 3- to 4-fold higher dethiolase activity than rat heart or liver. These data indicate that protein dethiolase activity is ubiquitous and that normal expression of the two dethiolase activities varies considerably. A partially purified cardiac NADPH-dependent dethiolase acted on Phb approximately 1.5 times faster than CAIII, and a glutathione (GSH)-dependent dethiolase acted on Phb 3 times faster than CAIII. The Km for glutathione for the GSH-dependent dethiolase was 15 μm with Phb as substrate and 10 μm with CAIII. Thus, the GSH-dependent dethiolase is probably not affected by normal changes in the cardiac glutathione content (normally approximately 3 mm). Partially purified cardiac NADPH-dependent dethiolase was inactivated by BCNU (N,N′-bis(2-chloroethyl)-N-nitrosourea) and the GSH-dependent dethiolase was unaffected under similar conditions. In a soluble extract from bovine heart, 200 μm BCNU inhibited NADPH-dependent dethiolase by more than 60% but did not affect GSH-dependent activity. These results demonstrate that BCNU is a selective inhibitor of the NADPH-dependent dethiolase. © 1991.
