Persistence of chlorpropham (CIPC) in the concrete flooring of potato stores

The loss of the sprout suppressant, chlorpropham (CIPC), to the fabric of potato stores is currently of concern due to the risk of potential cross contamination of other crops subsequently housed in these stores. HPLC UV/VIS and GCMS methods were successfully employed to detect CIPC in the concrete flooring of research and commercial potato stores with histories of between 1 and 26 years of use. The concentrations in identical research stores, with different numbers of applications, were in the range 0.58–5.7 and 3.4–112 μg g−1, suggesting the magnitude of contamination was influenced by the number of applications. Commercial store A, with a history of 18 seasons of applications (estimate of total CIPC applied 2040 kg), had concentrations varying between 6 and 48 μg g−1 in the top three centimetres, with more than 92% within the top centimetre. In contrast, commercial store B, with a history of less than five seasons of applications (estimate of total CIPC applied 319 kg), had concentrations varying between 0.58 and 304 μg g−1 in the top four centimetres, with less than 47% within the top centimetre. The difference in depth distributions between A and B may be due to the structural integrity of the concrete, which was much poorer in B. CIPC was persistent in all stores irrespective of the total quantities of CIPC applied and date of the final application

Determination of Chlorpropham (CIPC) residues, in the concrete flooring of potato stores, using quantitative (HPLC UV/VIS) and qualitative (GCMS) methods

Isopropyl-N-(3-chlorophenyl) carbamate (CIPC, common name Chlorpropham) is commonly used for post-harvest sprout inhibition in stored potatoes. It is applied as a thermal fog which results in loss to the fabric of the store and the atmosphere. Recently, there have been concerns in the United Kingdom because of cross contamination of other crop commodities that were stored in buildings with a history of CIPC usage. This cross contamination may have occurred because of retained residues in the fabric of the stores. The retention of CIPC in concrete is poorly understood; therefore the requirement for a robust analytical method for the detection and quantification of CIPC in concrete is a critical first step in tackling this problem. A method using High-Performance Liquid Chromatography with ultraviolet detection (HPLC UV/VIS) was validated. CIPC recoveries at three concentration levels (0.4, 4.0 and 40.0 µg g-1) were in the range of 90.7-97.0 % with relative standard deviations between 2.14-3.01 %. The limits of detection and quantification were 0.03 and 0.1 µg g-1 , respectively. This study confirmed that CIPC was persistent in concrete to a depth of 4 cm, with > 90 % within the top 1 cm of the flooring

The risk of chlorpropham cross-contamination of grain in potato stores

The contamination of food with pesticide residues is of significant concern to consumers and legislation has been implemented worldwide to ensure compliance with Maximum Residue Levels of chemicals in food. The occurrence of the potato sprout inhibitor, isopropyl N-(3-chlorophenyl) carbamate (chlorpropham or CIPC) residues on cereals, such as wheat, is of concern as this chemical is not authorised for use on cereals, and therefore the route of unintentional contamination warrants further investigation. This study reports on the risk of CIPC cross-contamination of grain that was stored in a commercial potato store and provides a method for low level quantification of CIPC in cereals. A High Performance Liquid Chromatography (HPLC UV/VIS) method for quantifying residues of CIPC in grains was successfully validated and the presence of CIPC was confirmed by Gas Chromatography Mass Spectrometry (GCMS). The magnitude of contamination in the grain was influenced by: (I) direct contact with the flooring of the store; (II) the headspace directly above the concrete surface and within the store itself and (III) contaminated dust/CIPC particles in the store atmosphere. Cross contamination is feasible irrespective of the CIPC concentrations in the concrete flooring and even with storage of grain at an elevated height above the concrete, suggesting that the route of cross contamination is a complex process involving physical and chemical (volatilization) factors. The results are significant for recommendations involving the storage of grain in buildings with a history of CIPC use and for remedial strategies for decontamination of these buildings

Importance of extra- and intracellular domains of TLR1 and TLR2 in NFkappa B signaling

Recognition of ligands by toll-like receptor (TLR) 2 requires interactions with other TLRs. TLRs form a combinatorial repertoire to discriminate between the diverse microbial ligands. Diversity results from extracellular and intracellular interactions of different TLRs. This paper demonstrates that TLR1 and TLR2 are required for ara-lipoarabinomannan- and tripalmitoyl cysteinyl lipopeptide-stimulated cytokine secretion from mononuclear cells. Confocal microscopy revealed that TLR1 and TLR2 cotranslationally form heterodimeric complexes on the cell surface and in the cytosol. Simultaneous cross-linking of both receptors resulted in ligand-independent signal transduction. Using chimeric TLRs, we found that expression of the extracellular domains along with simultaneous expression of the intracellular domains of both TLRs was necessary to achieve functional signaling. The domains from each receptor did not need to be contained within a single contiguous protein. Chimeric TLR analysis further defined the toll/IL-1R domains as the area of crucial intracellular TLR1-TLR2 interaction

Understanding the persistence, transformation and fate of CIPC (Chlorpropham) in commercial potato stores to help guard against cross-contamination.

The fate and distribution of the sprout suppressant chlorpropham (CIPC) in potato stores is uncertain. Detectable amounts of CIPC in any commodity exceeding the Maximum Residue Limit (MRL) renders it unfit for use in the EU. The MRL for CIPC on cereals is set at the limit of quantification (LOQ, 0.01 mg kg-1) because it is not permitted for use on these crops. Cross-contamination of cereals with CIPC is an emerging concern in the UK. Grain cross-contamination may have occurred during storage in buildings with a history of CIPC use, however, the retention of CIPC residues in the fabric of stores and the effect on grain cross-contamination is poorly understood. Unfortunately, even extensive cleaning of a store is not sufficient to remove CIPC residues from the infrastructure. Sensitive analytical methods are therefore required to detect CIPC in building materials to allow informed recommendations to be made to farmers about the re-use of stores for other crop commodities. Decontamination strategies are urgently required to allow valuable storage facilities to be used for the purpose they were intended. This project provides an understanding of the persistence, transformation and fate of CIPC in commercial potato stores to help guard against cross-contamination. An initial step in tackling the cross contamination was the development of sensitive analytical methods to detect CIPC and its degradation product 3 chloroaniline (3-CA) in the fabric of potato stores. Robust High- Performance Liquid Chromatography with Ultraviolet Detection (HPLC UV/VIS) and Gas Chromatography Mass Spectrometry (GCMS) methods were developed for quantifying and confirming the presence of CIPC and 3-CA in building material (concrete) and crop commodity (grains). The methods were successfully used in stores to determine: the degree of CIPC and 3-CA contamination in the concrete flooring; the degree and route of CIPC and 3-CA cross contamination of grains and the effectiveness of a sealant to prevent cross contamination. The distribution of CIPC and 3-CA in the concrete flooring of stores with histories between 1 and 25 years of application was determined. The degree of chemical penetration into the flooring was dependent on the physical composition of the concrete, with >90% in the top centimetre layer of less porous concrete. CIPC was persistent in all stores to a depth of at least 3 cm and this was irrespective of the date of the last CIPC application. The accumulation of residues in the flooring was also influenced by the quantities of applied CIPC, the point of CIPC entry into the store and the type of circulatory system used. The levels of contamination were more likely to be higher in areas closest to the point of entry into the stores. Of the stores studied, the magnitude of contamination was increased with the number of applications in research stores and vice versa in commercial stores. The degree of contamination in stores was influenced by air circulation causing heterogeneity of CIPC distribution. 3-CA was persistent in commercial stores with the distribution varying in the flooring. The methods developed in this project are invaluable for the detection of residues in stores and the knowledge gained on the magnitude of contamination is significant for risk assessment prior to the storage of non-potato crops in buildings with a history of CIPC use. In addition, this study provides invaluable information for decontamination strategies since it provides an indication on the depth of concrete that would require removal or treatment to allow stores to be re-used. The degree and route of cross contamination of grains was examined in commercial stores with histories of 16 and 25 years since the final application of CIPC. Cross contamination was feasible irrespective of the CIPC levels in the concrete flooring and provided evidence that the headspace in the general store, the headspace above the concrete flooring and dislodged contaminated dust particles in a store environment are all important routes of cross contamination. The duration of storage of grain influenced the magnitude of cross contamination, with an increase in magnitude for longer storage duration. The magnitude of cross contamination was increased in the vicinities of the points of CIPC entry into the stores because accumulation of residues in the concrete flooring and dust was higher in these areas. Therefore, the heterogeneity of CIPC distribution in the concrete flooring may influence the magnitude of cross contamination, with an increase in magnitude at higher levels of CIPC in the flooring. The storage of grains and other commodities with MRLs set at the LOQ for CIPC are at risk of cross contamination in contaminated buildings. Therefore, the reuse of potato stores for other commodities is not recommended. Decontamination strategies for removal of CIPC residues were explored. A xylene based sealant was ineffective in retaining residues and thus permitted cross contamination of grains in contact with the concrete flooring of the store. However, useful information with respect to the method of sealant application was gathered, with future benefits for other trials. Chemical degradation of CIPC with 3-decen-2-one was not observed, instead, a non-covalent complex involving a N-H…O hydrogen bond was formed. The reaction was reversible due to the type of bonding; suggesting decenone was not effective for the decontamination of CIPC on concrete. The complexes formed from the reaction, however, were unlikely to change the properties of CIPC present on building materials; preventing the formation of 3-CA. Therefore, decenone can be an alternative solvent for CIPC application in stores. Titanium dioxide incorporated in sealants or pillared clays and ozone are other promising decontamination strategies that require exploring

Neurosteroid Levels in the Orbital Frontal Cortex of Subjects With PTSD and Controls: A Preliminary Report

Background Neurosteroids mediate stress signaling and have been implicated in the pathogenesis of post-traumatic stress disorder (PTSD) in both preclinical and clinical studies. Compared to controls, subjects with PTSD exhibit altered neurosteroid levels in peripheral blood and cerebrospinal fluid as well as hypoactivity in the medial orbital frontal cortex (mOFC). Therefore, the aim of this study was to compare neurosteroid levels in the mOFC of subjects with PTSD ( n  = 18) and controls ( n  = 35). Methods Gray matter was dissected from fresh-frozen mOFC, and levels of the neurosteroids pregnenolone, allopregnanolone, pregnanolone, epiallopregnanolone, epipregnanolone, tetrahydrodeoxycorticosterone, and androsterone were determined by gas chromatography-tandem mass spectrometry. Results Analyses of unadjusted levels revealed that males with PTSD had significantly decreased levels of allopregnanolone ( p  = 0.03) compared to control males, and females with PTSD had significantly increased levels of pregnenolone ( p  = 0.03) relative to control females. After controlling for age, postmortem interval, and smoking status, results showed that males with PTSD had significantly decreased levels of androsterone ( t 46  = 2.37, p  = 0.02) compared to control males and females with PTSD had significantly increased levels of pregnanolone ( t 46  = −2.25, p  = 0.03) relative to control females. Conclusions To our knowledge, this is the first report of neurosteroid levels in postmortem brain tissue of subjects with PTSD. Although replication is required in other brain regions and a larger cohort of subjects, the results suggest a dysregulation of allopregnanolone and androsterone in males with PTSD and pregnanolone in females with PTSD in the mOFC