Effects of organochlorine pesticides on human and rat 17β-hydroxysteroid dehydrogenase 1 activity: Structure-activity relationship and in silico docking analysis

The objective of this study was to examine the effect of 11 organochlorine pesticides on human and rat 17β-Hydroxysteroid dehydrogenase 1 (17β-HSD1) in human placental and rat ovarian microsome and on estradiol production in BeWo cells. The results showed that the IC50 values for endosulfan, fenhexamid, chlordecone, and rhothane on human 17β-HSD1 were 21.37, 73.25, 92.80, and 117.69 μM. Kinetic analysis revealed that endosulfan acts as a competitive inhibitor, fenhexamid as a mixed/competitive inhibitor, chlordecone and rhothane as a mixed/uncompetitive inhibitor. In BeWo cells, all insecticides except endosulfan significantly decreased estradiol production at 100 μM. For rats, the IC50 values for dimethomorph, fenhexamid, and chlordecone were 11.98, 36.92, and 109.14 μM. Dimethomorph acts as a mixed inhibitor, while fenhexamid acts as a mixed/competitive inhibitor. Docking analysis revealed that endosulfan and fenhexamid bind to the steroid-binding site of human 17β-HSD1. On the other hand, chlordecone and rhothane binds to a different site other than the steroid and NADPH-binding site. Dimethomorph binds to the steroid/NADPH binding site, and fenhexamid binds to the steroid binding site of rat 17β-HSD1. Bivariate correlation analysis showed a positive correlation between IC50 values and LogP for human 17β-HSD1, while a slight negative correlation was observed between IC50 values and the number of HBA. ADMET analysis provided insights into the toxicokinetics and toxicity of organochlorine pesticides. In conclusion, this study identified the inhibitory effects of 3-4 organochlorine pesticides and binding mechanisms on human and rat 17β-HSD1, as well as their impact on hormone production.

Alterations of Systemic and Hepatic Metabolic Function Following Exposure to Trans-nonachlor in Low and High Fat Diet Fed Male Sprague Dawley Rats

The overall prevalence of metabolic diseases such as type 2 diabetes (T2D) and associated co-morbidities have increased at an alarming rate in the United States and worldwide. There is a growing body of epidemiological evidence implicating exposure to persistent organic pollutants (POPs), including legacy organochlorine (OC) pesticides and their bioaccumulative metabolites, in the pathogenesis of metabolic diseases. Therefore, the goal of the present study was to determine if exposure to trans-nonachlor, a bioaccumulative OC pesticide contaminant, in concert with high fat diet intake induced metabolic dysfunction. Briefly, male Sprague Dawley rats were exposed to trans-nonachlor (.5 or 5 ppm) in either a low fat (LFD) or high fat diet (HFD) for 16 weeks. At 8 weeks of intake, trans-nonachlor decreased serum triglyceride levels in LFD and HFD fed animals and at 16 weeks compared to LFD fed animals. Interestingly, serum glucose levels were decreased by trans-nonachlor (5 ppm) in LFD fed animals at 16 weeks. Serum free fatty acids were increased by trans-nonachlor exposure (5 ppm) in LFD fed animals at 16 weeks. HFD fed animals displayed signs of hepatic steatosis including elevated liver triglycerides, liver enzymes, and liver lipid peroxidation which were not significantly altered by trans-nonachlor exposure. However, there was a trans-nonachlor mediated increase in expression of fatty acid synthase in livers of LFD fed animals and not HFD fed animals. Thus, the present data indicate exposure to trans-nonachlor in conjunction with LFD or HFD intake produces both diet and exposure dependent effects on lipid and glucose metabolism.

A reassessment of the fungicidal efficacy of 1,3-dichloropropene, chloropicrin, and metam potassium against Macrophomina phaseolina in strawberry

BACKGROUND

The effectiveness of metam potassium, 1,3-dichloropropene, chloropicrin, and different ratios of 1,3-dichloropropene and chloropicrin on the reduction of natural and artificial inoculum of Macrophomina phaseolina were investigated in laboratory and field experiments. Additionally, a multivariate meta-analysis with data from six field trials conducted in Florida from 2012 to 2018 was performed.

RESULTS

In small-plot field experiments using drip stakes, the highest rate (468 L ha^-1 ) of metam potassium was most effective in controlling M. phaseolina in infected crowns buried at 15.2 cm from the point of fumigant injection, whereas none of the rates was able to reduce inoculum buried at 30.5 cm. In closed-container experiments, use of the highest rate of 1,3-dichloropropene (168 kg ha^-1 ) resulted in the highest level of pathogen control. Different rates of chloropicrin also reduced inoculum when compared to the non-treated control. 1,3-dichloropropene + chloropicrin at different ratios were also highly effective in controlling M. phaseolina. Results from the meta-analysis of open-field experiments indicated that metam potassium and 1,3-dichloropropene + chloropicrin (63:35, v:v) treatments were significantly more effective in reducing M. phaseolina than the 1,3-dichloropropene + chloropicrin (39:60, v:v) treatment; however, metam potassium was not as effective at the side of the beds.

CONCLUSION

1,3-dichloropropene alone and in mixture with chloropicrin were more effective in reducing inoculum of M. phaseolina than chloropicrin alone, indicating the fungicidal efficacy of 1,3-dichloropropene. Formulation with higher 1,3-dichloropropene concentration performed better than the formulation with higher chloropicrin concentration in field trials. Metam potassium was effective when applied at the highest rate, but with limited lateral movement perpendicular to the drip irrigation line. © 2022 Society of Chemical Industry.

Effects of chloropicrin fumigation combined with biochar on soil bacterial and fungal communities and Fusarium oxysporum

Chloropicrin (CP) can cause long-term damage to beneficial microbes which reduces soil health. Biochar (BC) can mitigate against the effects of CP by reducing the time for beneficial microbes to recover after CP fumigation. In this study, we used Real-Time Quantitative PCR to determine the effects of different rates of BC added to CP-fumigated soil on the speed of recovery of bacteria and fungi population and on changes to gene copy number of the target pathogen Fusarium oxysporum. And then we compared the structure and composition of the beneficial microbial community in the different treatments soil by using High throughput Illumina sequencing. As the results shown, adding 1 or 3% BC after CP fumigation accelerated the recovery of bacterial and fungal populations without increasing F. oxysporum abundance. BC also promoted the recovery of beneficial bacteria Rokubacteria and Latescibacteria damaged by CP. And these two bacteria may be related to the immunity of soil to F. oxysporum. In CP-fumigated soil, BC improved the disease resistance of the soil by increasing beneficial microbes, such as Steroidobacter, Sphingomonas, Purpureocillium and Mortierella. This combination of CP and BC is a new concept that could encourages the development of a healthy and sustainable soil ecosystems while controlling plant pathogens.

Chloropicrin alternated with dazomet improved the soil's physicochemical properties, changed microbial communities and increased strawberry yield

Chloropicrin (Pic) and dazomet (DZ) are effective soil fumigants that are often used to reduce soil-borne pathogens that would otherwise reduce crop yield. As Pic is scheduled to be banned, we investigated whether its consumption could be halved by alternating it with DZ. We observed that Pic alternated with DZ increased the soil NH₄⁺-N content by 28.74-47.07 times, increased available potassium content by 40.80%-46.81% and increased electrical conductivity by 39.23%-85.81%. It generally improved the soil's physicochemical properties. High-throughput DNA sequencing showed that Pic alternated with DZ changed the taxonomic diversity of bacteria and fungi by increasing the relative abundance of Bacillus and Firmicutes, and by decreasing Proteobacteria, Acidobacteria and Sphingomonas. Moreover, Pic alternated with DZ can inhibit key soil pathogens by more than 90% and significantly increased strawberry yield by 78.22%-116.12%. In terms of strawberry production, we recommend using DZ in the first year and Pic in the second year. Our results showed significant ecological benefit and yield benefit when Pic consumption was halved by alternating it with DZ.

Single molecule analysis indicates stimulation of MUTYH by UV-DDB through enzyme turnover

The oxidative base damage, 8-oxo-7,8-dihydroguanine (8-oxoG) is a highly mutagenic lesion because replicative DNA polymerases insert adenine (A) opposite 8-oxoG. In mammalian cells, the removal of A incorporated across from 8-oxoG is mediated by the glycosylase MUTYH during base excision repair (BER). After A excision, MUTYH binds avidly to the abasic site and is thus product inhibited. We have previously reported that UV-DDB plays a non-canonical role in BER during the removal of 8-oxoG by 8-oxoG glycosylase, OGG1 and presented preliminary data that UV-DDB can also increase MUTYH activity. In this present study we examine the mechanism of how UV-DDB stimulates MUTYH. Bulk kinetic assays show that UV-DDB can stimulate the turnover rate of MUTYH excision of A across from 8-oxoG by 4-5-fold. Electrophoretic mobility shift assays and atomic force microscopy suggest transient complex formation between MUTYH and UV-DDB, which displaces MUTYH from abasic sites. Using single molecule fluorescence analysis of MUTYH bound to abasic sites, we show that UV-DDB interacts directly with MUTYH and increases the mobility and dissociation rate of MUTYH. UV-DDB decreases MUTYH half-life on abasic sites in DNA from 8800 to 590 seconds. Together these data suggest that UV-DDB facilitates productive turnover of MUTYH at abasic sites during 8-oxoG:A repair.

Dictyostelium Differentiation-Inducing Factor-1 Promotes Glucose Uptake, at Least in Part, via an AMPK-Dependent Pathway in Mouse 3T3-L1 Cells

Differentiation-inducing factor-1 (DIF-1) is a chlorinated alkylphenone (a polyketide) found in the cellular slime mold Dictyostelium discoideum. DIF-1 and its derivative, DIF-1(3M) promote glucose consumption in vitro in mammalian cells and in vivo in diabetic rats; they are expected to be the leading antiobesity and antidiabetes compounds. In this study, we investigated the mechanisms underlying the actions of DIF-1 and DIF-1(3M). In isolated mouse liver mitochondria, these compounds at 2-20 μM promoted oxygen consumption in a dose-dependent manner, suggesting that they act as mitochondrial uncouplers, whereas CP-DIF-1 (another derivative of DIF-1) at 10-20 μM had no effect. In confluent mouse 3T3-L1 fibroblasts, DIF-1 and DIF-1(3M) but not CP-DIF-1 induced phosphorylation (and therefore activation) of AMP kinase (AMPK) and promoted glucose consumption and metabolism. The DIF-induced glucose consumption was reduced by compound C (an AMPK inhibitor) or AMPK knock down. These data suggest that DIF-1 and DIF-1(3M) promote glucose uptake, at least in part, via an AMPK-dependent pathway in 3T3-L1 cells, whereas cellular metabolome analysis revealed that DIF-1 and DIF-1(3M) may act differently at least in part.

HaloTag-Targeted Sirtuin-Rearranging Ligand (SirReal) for the Development of Proteolysis-Targeting Chimeras (PROTACs) against the Lysine Deacetylase Sirtuin 2 (Sirt2)*

We have discovered the sirtuin-rearranging ligands (SirReals) as a novel class of highly potent and selective inhibitors of the NAD+ -dependent lysine deacetylase sirtuin 2 (Sirt2). In previous studies, conjugation of a SirReal with a ligand for the E3 ubiquitin ligase cereblon to form a so-called proteolysis-targeting chimera (PROTAC) enabled small-molecule-induced degradation of Sirt2. Herein, we report the structure-based development of a chloroalkylated SirReal that induces the degradation of Sirt2 mediated by Halo-tagged E3 ubiquitin ligases. Using this orthogonal approach for Sirt2 degradation, we show that other E3 ligases than cereblon, such as the E3 ubiquitin ligase parkin, can also be harnessed for small-molecule-induced Sirt2 degradation, thereby emphasizing the great potential of parkin to be used as an E3 ligase for new PROTACs approaches. Thus, our study provides new insights into targeted protein degradation in general and Sirt2 degradation in particular.

Exposure to Low Doses of Dechlorane Plus Promotes Adipose Tissue Dysfunction and Glucose Intolerance in Male Mice

The prevalence of type 2 diabetes (T2D) continues to increase worldwide. It is well established that genetic susceptibility, obesity, overnutrition and a sedentary life style are risk factors for the development of T2D. However, more recently, studies have also proposed links between exposure to endocrine-disrupting chemicals (EDCs) and altered glucose metabolism. Human exposure to environmental pollutants that are suspected to have endocrine disruptor activity is ubiquitous. One such chemical is Dechlorane Plus (DP), a flame retardant, that is now detected in humans and the environment. Here we show that exposure of mice to low, environmentally relevant doses of DP promoted glucose intolerance in mice fed a high-fat diet independent of weight gain. Furthermore, DP had pronounced effects on the adipose tissue, where it induced the development of hypertrophied white adipose tissue (WAT), and increased serum levels of resistin, leptin, and plasminogen activator inhibitor-1. In addition, DP exposure induced "whitening" of brown adipose tissue (BAT), and reduced BAT uncoupling protein 1 expression. Importantly, some of these effects occurred even when the mice were fed a regular, low-fat, diet. Finally, WAT adipogenic markers were reduced with DP treatment in the WAT. We also show that DP directly inhibited insulin signaling in murine adipocytes and human primary subcutaneous adipocytes in vitro. Taken together, our results show that the exposure to low and environmentally relevant levels of DP may contribute to the development of T2D.

Theoretical study of fluorinated bioisosteres of organochlorine compounds as effective and eco-friendly pesticides

Chlordane is a worldwide banned organochlorine insecticide because of its hazard to animal and human health. It is also a persistent organic pollutant, which can affect either the soil or the aquatic life. The same applies to other chlorinated cyclodiene insecticides, such as dieldrin and aldrin. In turn, organofluorine compounds have a widespread use in agriculture. Therefore, density functional calculations and docking studies showed that the bioisosteric replacement of chlorines in the above-mentioned compounds by fluorines improves some physicochemical parameters used to estimate the toxicity and environmental risk of these compounds, as well as the ligand-enzyme (GABA_A receptor-chloride channel complex) interactions related to their insecticidal activity. This work is an effort to provide an improved new class of organofluorine pesticides.

Measurement of junctional tension in epithelial cells at the onset of primitive streak formation in the chick embryo via non-destructive optical manipulation

Directional cell intercalations of epithelial cells during gastrulation has, in several organisms, been shown to be associated with a planar cell polarity in the organisation of the actin-myosin cytoskeleton and is postulated to reflect directional tension that drives oriented cell intercalations. We have characterised and applied a recently introduced non-destructive optical manipulation technique to measure the tension in individual epithelial cell junctions of cells in various locations and orientations in the epiblast of chick embryos in the early stages of primitive streak formation. Junctional tension of mesendoderm precursors in the epiblast is higher in junctions oriented in the direction of intercalation than in junctions oriented perpendicular to the direction of intercalation and higher than in junctions of other cells in the epiblast. The kinetic data fit best with a simple viscoelastic Maxwell model, and we find that junctional tension, and to a lesser extent viscoelastic relaxation time, are dependent on myosin activity.

A Systematic Review on Organophosphate Pesticide and Type II Diabetes Mellitus

Organophosphate (OP) pesticides are extremely poisonous and they affect the glucose breakdown in numerous and mechanism. There are higher evidence of stimulating diabetes mellitus through OP pesticides especially the type II diabetes. The upsurge in the level of glucose (hyperglycemia), and insulin resistance along with their related outcomes are discussed in this review. The data related to investigational and clinical techniques endorse a connection amid such molecular mechanism and compounds of OPs. Numerous studies conducted till March 2018 have reported OP' exposures and diabetes-related outcomes. The acute and chronic exposure in case of these insecticides and diabetesrelated outcomes are defined in this study. Initially, it was declared that OPs prompt to hyperglycemia. Then, a high association of glucose in blood beside insulin was found out. The affirmation from some clinical as well as investigational studies supported a connection amid exposure to OP and diabetes, yet in maximum number of instances, non-specific diabetes occurs.

Adulticide Resistance Status of Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia: A Statewide Assessment

Resistance status of Aedes albopictus (Diptera: Culicidae) collected from Sabah, East Malaysia, was evaluated against four major classes of adulticides, namely pyrethroid, carbamate, organochlorine, and organophosphate. Adult bioassays conforming to WHO standard protocols were conducted to assess knockdown and mortality rates of Ae. albopictus. Among tested pyrethroid adulticides, only cyfluthrin, lambda-cyaholthrin, and deltamethrin were able to inflict total knockdown. The other adulticide classes mostly failed to cause any knockdown; the highest knockdown rate was only 18.33% for propoxur. With regards to mortality rate, Ae. albopictus was unanimously susceptible toward all pyrethroids, dieldrin, and malathion, but exhibited resistance toward bendiocarb, propoxur, dichlorodiphenyltrichloroethane, and fenitrothion. Additionally, correlation analysis demonstrated cross-resistance between bendiocarb and propoxur, and malathion and propoxur. In conclusion, this study has disclosed that pyrethroids are still generally effective for Aedes control in Sabah, Malaysia. The susceptibility status of Ae. albopictus against pyrethroids in descending order was cyfluthrin > lambda-cyhalothrin > deltamethrin > etofenprox > permethrin.

Synthetic approaches and pharmaceutical applications of chloro-containing molecules for drug discovery: A critical review

At present more than 250 FDA approved chlorine containing drugs were available in the market and many pharmaceutically important drug candidates in pre-clinical trials. Thus, it is quite obvious to expect that in coming decades there will be an even greater number of new chlorine-containing pharmaceuticals in market. Chlorinated compounds represent the family of compounds promising for use in medicinal chemistry. This review describes the recent advances in the synthesis of chlorine containing heterocyclic compounds as diverse biological agents and drugs in the pharmaceutical industries for the inspiration of the discovery and development of more potent and effective chlorinated drugs against numerous death-causing diseases.

The Efficacy of Semiselective Chemicals and Chloropicrin/1,3-Dichloropropene-Containing Fumigants in Managing Apple Replant Disease in South Africa

Apple replant disease (ARD) is a biological phenomenon that is encountered when old apple orchards are replanted, resulting in tree growth and yield reductions in young trees. Three ARD orchard trials were conducted, which showed that semiselective chemicals (fenamiphos, metalaxyl, imidacloprid, and phosphonates) used independently, two fumigant formulations (33.3% chloropicrin and 60.8% 1,3-dichloropropene [Pic33-1,3D] and 57.% chloropicrin and 38% 1,3 dichloropropene [Pic57-1,3D]), and semiselective chemicals combined with Pic33-1,3D or Pic57-1,3D all contributed to significant increases in tree growth (trunk diameter and shoot length) relative to the untreated control 3 to 4 years postplanting. The treatments did not differ significantly from each other in improving tree growth. Yield was more indicative of treatment efficacy, but this varied between the three orchards. The Pic33-1,3D fumigant in combination with semiselective chemistries was the most consistent in significantly increasing cumulative yields. The Pic57-1,3D treatment was superior in increasing yields relative to the Pic33-1,3D treatment, because (i) it significantly increased cumulative yields in comparison with the Pic33-1,3D treatment in one orchard and (ii) in another orchard, a significant increase in yield was obtained with Pic57-1,3D relative to the control treatment but not with the Pic33-1,3D treatment. The quantification of ARD causative agents 20 months postplant showed that Phytophthora cactorum contributed to disease development in all three orchards; significant negative correlations existed between the quantity of P. cactorum DNA detected in tree roots and tree growth and less often, yield. In two orchards, only some of the treatments that significantly reduced the quantity of P. cactorum DNA in tree roots relative to the control also resulted in a significant increase in tree growth. Some of the aforementioned trends were also evident for Pratylenchus spp. root densities in two of the orchards. There was a significant positive correlation between P. cactorum root DNA quantities and Pratylenchus spp. root densities. Pythium spp. and "Cylindrocarpon"-like DNA quantities detected in tree roots typically were not indicative of treatment efficacy. However, a significant positive correlation existed between these two pathogen groups, suggesting complex interactions not associated with pathogen quantities per se.

Sustainable alternatives to 1,3-dichloropropene for controlling root-knot nematodes and fungal pathogens in melon crops in Mediterranean soils: Efficacy and effects on soil quality

The control of agricultural pests is key to maintain economically viable crops. Increasing environmental awareness, however, is leading to more restrictive European policies regulating the use of certain pesticides due to their impact on human health and the soil system. Given this context, we evaluated the efficacy of three alternatives to the soil fumigant 1,3-dichloropropene (1,3-D), which is currently banned in Europe: two non-fumigant nematicides [oxamyl (OX) and fenamiphos (FEN)] and the soil fumigant dimethyl disulfide (DMDS). We analysed the efficiency of these pesticides against root-knot nematodes and soil fungal pathogens (determined by qPCR) as well as the soil biological quality after treatments application (estimated by enzyme activities). Among treatments, 1,3-D and DMDS significantly reduced nematode populations. FEN was more effective in sandy soil, while OX had no effect in any soil. OX and FEN had no effect on fungal pathogens, whereas DMDS reduced the abundance of Rhizoctonia solani and Fusarium solani at the root level in clay-loam soil. Soil quality decreased after treatment application but then recovered throughout the experiment, indicating the possible dissipation of the pesticides. Our findings support DMDS as a potential sustainable alternative for controlling root-knot nematodes and fungal pathogens due to its effectiveness in both studied soils, although its negative impact on soil biological quality in sandier soils must be taken into account. Main finding of the work. DMDS is a reliable alternative to 1,3-D for controlling agricultural pest but its inhibitory effect on soil enzyme activities varied according to the soil characteristics.

Response of microbial communities to different organochlorine pesticides (OCPs) contamination levels in contaminated soils

Understanding microbial community structure and diversity in contaminated soils helps optimize the bioremediation strategies and performance. This study investigated the roles of environmental variables and contamination levels of organochlorine pesticides (OCPs) in shaping microbial community structure at an abandoned aged insecticide plant site. In total, 28 bacterial phyla were identified across soils with different physiochemical properties and OCPs levels. Proteobacteria, Bacterioidetes and Firmicutes represented the dominant lineages, and accounted for 60.2%-69.2%, 5.6%-9.7% and 6.7%-9.4% of the total population, respectively. The overall microbial diversities, in terms of phylogenetic diversity and phylotype richness, were correlated with the contents of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in soils, as well as other soil properties including total nitrogen, dissolved organic carbon, pH and vegetation. The multivariate regression tree (MRT) analysis revealed that the soil microbial diversity was significantly impacted by vegetation, which explained 31.8% of the total variation, followed by OCPs level (28.3%), total nitrogen (12.4%), dissolved organic carbon (6.3%) and pH (2.4%). Our findings provide new insights and implications into the impacts on soil microbial community by OCPs contamination and other environmental variables, and offer potential strategic bioremediation for the management of OCPs contaminated sites.

Dictyostelium: An Important Source of Structural and Functional Diversity in Drug Discovery

The cellular slime mold Dictyostelium discoideum is an excellent model organism for the study of cell and developmental biology because of its simple life cycle and ease of use. Recent findings suggest that Dictyostelium and possibly other genera of cellular slime molds, are potential sources of novel lead compounds for pharmacological and medical research. In this review, we present supporting evidence that cellular slime molds are an untapped source of lead compounds by examining the discovery and functions of polyketide differentiation-inducing factor-1, a compound that was originally isolated as an inducer of stalk-cell differentiation in D. discoideum and, together with its derivatives, is now a promising lead compound for drug discovery in several areas. We also review other novel compounds, including secondary metabolites, that have been isolated from cellular slime molds.

Evidences of N2O Emissions in Chloropicrin-Fumigated Soil

The mechanism of N₂O production following chloropicrin (CP) fumigation was investigated in this study. Our results showed that CP fumigation increased N₂O production from 23 to 25 times in comparison with the control and significantly decreased the abundance of 16S rRNA and N-cycling functional genes. CP also decreased the soil bacterial diversity and caused a shift in the community composition. The N₂O emissions in fumigated soil were significantly correlated with soil environmental factors (NH₄⁺, dissolved amino acid, microbial biomass nitrogen, and NO₃^-) but were not correlated with the abundance of functional genes. Metatranscriptomes and dual-label ¹⁵N-¹⁸O isotope analysis revealed that CP fumigation inhibited the expression of gene families involved in N₂O production and sink processes and shifted the main pathway of N₂O production from nitrification to denitrification. These results provided useful information for environmental safety assessments of CP in China, to improve our understanding of the N-cycling pathways in fumigated soils.

Synthesis and Biological Evaluation of Tripartin, a Putative KDM4 Natural Product Inhibitor, and 1-Dichloromethylinden-1-ol Analogues

The natural product tripartin has been reported to inhibit the N-methyl-lysine histone demethylase KDM4A. A synthesis of tripartin starting from 3,5-dimethoxyphenylacrylic acid was developed, and the enantiomers were separated by chiral HPLC. We observed that both tripartin enantiomers manifested an apparent increase in H3K9me3 levels when dosed in cells, as measured by western blot analysis. Thus, there is no enantiomeric discrimination toward this natural product in terms of its effects on cellular histone methylation status. Interestingly, tripartin did not inhibit isolated KDM4A-E under our assay conditions (IC50 >100 μm). Tripartin analogues with a dichloromethylcarbinol group derived from the indanone scaffold were synthesized and found to be inactive against isolated recombinant KDM4 enzymes and in cell-based assays. Although the precise cellular mode of action of tripartin is unclear, our evidence suggests that it may affect histone methylation status via a mechanism other than direct inhibition of the KDM4 histone demethylases.

Enrichment and physiological responses of dechlorane plus on juvenile marine macroalgae (Ulva pertusa)

Dechlorane Plus (DP), a chlorinated flame retardant, is increasingly reported in aquatic ecosystems worldwide. But little information is available regarding the toxicity of DP in marine organisms, especially in macroalgae. The objective of this study was to investigate effects of DP exposure on photosynthesis, oxidative stress and its enrichment in juvenile marine macroalgae (Ulva pertusa). Following 21- day uptake and 21- day depuration (10^-8 mol/L), algae accumulated 1.18 times of DP compared to the initial concentration. Anti-DP was prone to accumulate in juvenile macroalgae. The enrichment of DP affected the physiological responses in algae. After 1, 7 and 14 days DP exposure (10^-8, 10^-7 and 10^-6 mol/L), antioxidant enzymes (SOD and CAT) activities and MDA content changed in a dose and time depended manner. Chlorophyll fluorescence parameters, including F_v/F_m, Φ_PSII and ETR decreased with the increasing DP concentration. It indicated that DP leads to a low rate of light energy utilization in algae which may ascribe to the oxidative damage induced by DP enrichment. Present study provides insight into the toxicological effects of DP on marine macroalgae, which is useful for risk assessment of DP in intertidal zone ecosystems.

A novel non-ATP competitive FGFR1 inhibitor with therapeutic potential on gastric cancer through inhibition of cell proliferation, survival and migration

Fibroblast growth factor receptor 1 (FGFR1), belonging to receptor tyrosine kinases (RTKs), possesses various biological functions. Over-expression of FGFR1 has been observed in multiple human malignancies. Hence, targeting FGFR1 is an attractive prospect for the advancement of cancer treatment options. Here, we present a novel small molecular FGFR1 inhibitor L16H50, which can inhibit FGFR1 kinase in an ATP-independent manner. It potently inhibits FGFR1-mediated signaling in a gastric cancer cell line, resulting in inhibition of cell growth, survival and migration. It also displays an outstanding anti-tumor activity in a gastric cancer xenograft tumor model by targeting FGFR1 signaling. These results show that L16H50 is a potent non-ATP-competitive FGFR1 inhibitor and may provide strong rationale for its evaluation in gastric cancer patients.

Lepistatins A-C, chlorinated sesquiterpenes from the cultured basidiomycete Lepista sordida

Three new chlorinated sesquiterpenes, named lepistatins A-C, were isolated from the culture broth of Basidiomycete Lepista sordida. The structures were determined by the analysis of spectroscopic data including HREIMS and 1D and 2D NMR. The absolute configuration of lepistatin B was determined by comparing the specific rotation and circular dichroism spectrum with those of known structurally related compounds bearing the same chiral carbon. The structures of lepistatins A-C feature the indanone core structure, but differ from other indanone-containing sesquiterpenes of fungal origin by the alkyl substitution pattern. This indicates that lepistatins A-C probably possess a new sesquiterpene scaffold derived from the common precursor, trans-humulyl cation, by an alternative cyclization.

Isolation, Synthesis, and Biological Activity of Chlorinated Alkylresorcinols from Dictyostelium Cellular Slime Molds

Eight chlorinated alkylresorcinols, monochasiol A-H (1-8), were isolated from the fruiting bodies of Dictyostelium monochasioides. Compounds 1-8 were synthesized to confirm their structures and to obtain sufficient material for performing biological tests. Monochasiol A (1) selectively inhibited the concanavalin A-induced interleukin-2 production in Jurkat cells, a human T lymphocyte cell line. Monochasiols were biogenetically synthesized by the combination of biosynthetic enzymes relating to the principal polyketides, MPBD and DIF-1, produced by Dictyostelium discoideum.

Myosin-1 inhibition by PClP affects membrane shape, cortical actin distribution and lipid droplet dynamics in early Zebrafish embryos

Myosin-1 (Myo1) represents a mechanical link between the membrane and actin-cytoskeleton in animal cells. We have studied the effect of Myo1 inhibitor PClP in 1-8 cell Zebrafish embryos. Our results indicate a unique involvement of Myo1 in early development of Zebrafish embryos. Inhibition of Myo1 (by PClP) and Myo2 (by Blebbistatin) lead to arrest in cell division. While Myo1 isoforms appears to be important for both the formation and the maintenance of cleavage furrows, Myo2 is required only for the formation of furrows. We found that the blastodisc of the embryo, which contains a thick actin cortex (~13 μm), is loaded with cortical Myo1. Myo1 appears to be crucial for maintaining the blastodisc morphology and the actin cortex thickness. In addition to cell division and furrow formation, inhibition of Myo1 has a drastic effect on the dynamics and distribution of lipid droplets (LDs) in the blastodisc near the cleavage furrow. All these results above are effects of Myo1 inhibition exclusively; Myo2 inhibition by blebbistatin does not show such phenotypes. Therefore, our results demonstrate a potential role for Myo1 in the maintenance and formation of furrow, blastodisc morphology, cell-division and LD organization within the blastodisc during early embryogenesis.

Dioxin-like activities, halogenated flame retardants, organophosphate esters and chlorinated paraffins in dust from Australia, the United Kingdom, Canada, Sweden and China

The concentrations of organic flame retardants (FRs) and dioxin-like activities in dust collected from five countries were investigated. The correlations between the concentrations of the different groups of FRs and dioxin-like activities were examined. Chlorinated paraffins (CPs, C₉ to C₃₁) were found in the highest concentration (median ∑CP 700 μg/g, range 280-4750 μg/g), followed by organophosphate esters (median ∑₁₃OPEs 56 μg/g, range 21-110 μg/g), halogenated flame retardants (median ∑₁₇HFRs 3.3 μg/g, range 0.87-14 μg/g) and polybrominated diphenyl ethers (median ∑₁₇PBDEs 2.8 μg/g, range 0.46-11 μg/g). There were no significant differences in concentrations of the FRs among the countries but differences in PBDE and CP congener profiles were found. BDE209 predominated in dust from Australia, the UK, Sweden and China, ranging from 50 to 70% of total PBDEs. The lowest percentage of BDE209 was found in the dust from Canada, representing only 20% of total PBDEs. For CPs in dust from Sweden, the long-chain CPs (especially C₁₈ congeners) predominated, while for other countries, medium-chain CPs (especially C₁₄ congeners) predominated. The dioxin-activities of the dusts ranged from 58 to 590 pg CALUX-TEQ/g, and had a median of 200 pg CALUX-TEQ/g. There were significant positive correlations between concentrations of PBDEs and CPs with dioxin-like activities. The dioxin-like activity may be due to the presence of polychlorinated or polybrominated dioxin/furans (PBDD/DFs) or polychlorinated naphthalenes (PCNs) in the dust. The PBDD/DFs are known impurities and degradation product of the penta-BDE mixture, and PCNs are known impurities of CPs which exhibit dioxin-like activities.

Dichlorodiphenyltrichloroethane (DDT) induced extracellular vesicle formation: a potential role in organochlorine increased risk of Parkinson's disease

A number of studies have demonstrated that rural living and exposure to pesticides such as dichlorodiphenyltrichloroethane (DDT) highly increase the chances of developing Parkinson's disease. In a previous work, we have found that DDT leads to the formation of vesicular buds that are released from the cells upon fusion of an intermediate endocytic compartment with the plasma membrane. Since extracellular vesicles like exosomes have been implicated in the development of neurodegenerative diseases through the propagation of neurotoxic misfolded proteins from neuron to neuron, in this minireview we propose that organochlorine pesticides could enhance the risk of neurodegenerative diseases by increasing the formation of exosomes.

Monochlorinated calocerins A-D and 9-oxostrobilurin derivatives from the basidiomycete Favolaschia calocera

Eight previously undescribed compounds were isolated and characterised from the supernatant and mycelium of a culture of the basidiomycete Favolaschia calocera originating from Kakamega equatorial rainforest in Kenya. These were: 9- oxostrobilurins A, G, K and I and the four monochlorinated calocerins A, B, C and D. The calocerins extend our knowledge of halogenated compounds obtained from natural sources. Four further known compounds were also identified: strobilurin G, favolon, pterulinic acid and 2,3 -dihydro-1-benzoxepin derivative. The four oxostrobilurins exhibited prominent antifungal and cytotoxic activities while the four calocerins only showed cytotoxic activity.

Transcriptional Induction of Metallothionein by Tris(pentafluorophenyl)stibane in Cultured Bovine Aortic Endothelial Cells

Vascular endothelial cells cover the luminal surface of blood vessels and contribute to the prevention of vascular disorders such as atherosclerosis. Metallothionein (MT) is a low molecular weight, cysteine-rich, metal-binding, inducible protein, which protects cells from the toxicity of heavy metals and active oxygen species. Endothelial MT is not induced by inorganic zinc. Adequate tools are required to investigate the mechanisms underlying endothelial MT induction. In the present study, we found that an organoantimony compound, tris(pentafluorophenyl)stibane, induces gene expression of MT-1A and MT-2A, which are subisoforms of MT in bovine aortic endothelial cells. The data reveal that MT-1A is induced by activation of both the MTF-1-MRE and Nrf2-ARE pathways, whereas MT-2A expression requires only activation of the MTF-1-MRE pathway. The present data suggest that the original role of MT-1 is to protect cells from heavy metal toxicity and oxidative stress in the biological defense system, while that of MT-2 is to regulate intracellular zinc metabolism.

Mechanisms for 1,3-Dichloropropene Dissipation in Biochar-Amended Soils

Biochar, which is organic material heated under a limited supply of oxygen, has the potential to reduce fumigant emissions when incorporated in the soil, but the mechanisms are not fully understood. The objective of this study was to determine the effects of biochar properties, amendment rate, soil microbe, moisture, temperature, and soil type on the fate of 1,3-dichloropropene (1,3-D) isomers in laboratory incubation experiments by assessing the 1,3-D degradation rate and adsorption capacity. 1,3-D dissipation rates were significantly reduced due to strong adsorption by biochar, which was also strongly affected by biochar type. Following a 1% biochar amendment, the half-lives of 1,3-D in soil were increased 2.5-35 times. The half-lives of 1,3-D in soil were strongly affected by soil moisture, temperature, and amendment rate. The effects of sterilization on 1,3-D degradation were much smaller in biochar-amended soils than in nonsterilized soils, which suggests the importance of abiotic pathways with biochar's presence. Dissipation of 1,3-D in biochar was divided into adsorption (49-93%) and chemical degradation pathways. Biochar properties, such as specific surface area (SSA), pH, water content, carbon content, and feedstock, all appeared to affect 1,3-D dissipation with potentially complex interactions. The biochar (air-dry) water content was highly correlated with 1,3-D adsorption capacity and thus can serve as an important predictor for fumigant mitigation use. The fate of the adsorbed fumigant onto biochar requires further examination on potential long-term environmental impacts before guidelines for biochar as a field practice to control fumigant emissions can be formulated.

The association of serum trans-nonachlor levels with atherosclerosis

Recent epidemiological studies suggest a strong association between exposure to environmental contaminants, including organochlorine (OC) insecticides or their metabolites, and development of pathologies, such as atherosclerosis, in which oxidative stress plays a significant etiological role. Biomarkers of systemic oxidative stress have the potential to link production of reactive oxygen species (ROS), which are formed as a result of exposure to xenobiotic toxicants, and underlying pathophysiological states. Measurement of F2-isoprostane concentrations in body fluids is the most accurate and sensitive method currently available for assessing in vivo steady-state oxidative stress levels. In the current study, urinary concentrations of F2-isoprostanes and serum levels of persistent OC compounds p,p'-dichlorodiphenyldichloroethene (DDE), trans-nonachlor (a component of the technical chlordane mixture), and oxychlordane (a chlordane metabolite) were quantified in a cross-sectional study sample and the association of these factors with a clinical diagnosis of atherosclerosis determined. Urinary isoprostane levels were not associated with atherosclerosis or serum concentrations of OC compounds in this study sample. However, occurrence of atherosclerosis was found to be associated with serum trans-nonachlor levels. DDE and oxychlordane were not associated with atherosclerosis. This finding supports current evidence that exposure to environmental factors is a risk factor for atherosclerosis, in addition to other known risk factors.

Fumigation efficacy and emission reduction using low-permeability film in orchard soil fumigation

BACKGROUND

Many orchards use fumigation to control soilborne pests prior to replanting. Controlling emissions is mandatory to reduce air pollution in California. This research evaluated the effects of plastic film type [polyethylene (PE) or totally impermeable film (TIF)], application rate of Telone C35 [full (610 kg ha(-1) ), 2/3 or 1/3 rates] and carbonation at 207 kPa on fumigant transport (emission and in soil) and efficacy.

RESULTS

While increasing fumigant concentrations under the tarp, TIF reduced emissions >95% (∼2% and <1% of total applied 1,3-dichloropropene and chloropicrin respectively) relative to bare soil, compared with ∼30% reduction by PE. All fumigation treatments, regardless of film type, provided good nematode control above 100 cm soil depth; however, nematode survival was high at deeper depths. Weed emergence was mostly affected by tarping and fumigant rate, with no effects from the carbonation.

CONCLUSION

TIF can effectively reduce fumigant emissions. Carbonation under the studied conditions did not improve fumigant dispersion and pest control. The 2/3 rate with TIF controlled nematodes as effectively as the full rate in bare soil or under the PE film to 100 cm soil depth. However, control of nematodes in deeper soil remains a challenge for perennial crops.

Anticonvulsant and Toxicological Evaluation of Parafluorinated/Chlorinated Derivatives of 3-Hydroxy-3-ethyl-3-phenylpropionamide

Although the anticonvulsant activity of 3-hydroxy-3-ethyl-3-phenylproionamide (HEPP) is well-known, its use is limited by the pharmacotoxicological profile. We herein tested its fluorinated and chlorinated derivatives (F-HEPP and Cl-HEPP) with two seizure models, maximal electroshock seizures (MES), and intraperitoneal pentylenetetrazole (PTZ) administration. Neurotoxicity was examined via the rotarod test. With in silico methods, binding was probed on possible protein targets-GABAA receptors and the sodium channel Nav1.2. The median effective doses (ED50) of HEPP, F-HEPP, and Cl-HEPP in the MES seizure model were 129.6, 87.1, and 62.0 mg/kg, respectively, and 66.4, 43.5, and in the PTZ seizure model 43.5 mg/kg. The HEPP-induced neurotoxic effect, which occurred at twice the ED50 against MES (p < 0.05), did not occur with F-HEPP or Cl-HEPP. Docking studies revealed that all tested ligands bound to GABAA receptors on a site near to the benzodiazepine binding site. However, on the sodium channel open pore Nav1.2, R-HEPP had interactions similar to those reported for phenytoin, while its enantiomer and the ligands F-HEPP and Cl-HEPP reached a site that could disrupt the passage of sodium. Our results show that, as anticonvulsant agents, parahalogen substituted compounds have an advantageous pharmacotoxicological profile compared to their precursor.

Identification of California Condor Estrogen Receptors 1 and 2 and Their Activation by Endocrine Disrupting Chemicals

Recently, California condors (Gymnogyps californianus) have been reintroduced to coastal regions of California where they feed on marine mammal carcasses. There is evidence that coastal-dwelling condors experience reproductive issues, such as eggshell thinning, likely resulting from exposure to endocrine-disrupting chemicals (EDCs). To address this problem, we have identified and cloned condor estrogen receptors (ESRs) 1 and 2 and characterized their activation by EDCs present in the coastal habitats where condors reside. Dichlorodiphenyltrichloroethane (DDT) and its metabolites all activated ESR1 and ESR2, although their relative potency differed between the receptors. Bisphenol A, dieldrin, trans-nonachlor, and polychlorinated biphenyl 52 (PCB52) moderately activated both ESRs, whereas PCB138 and PCB153 stimulated little to no activation. Overall, EDC activation of condor ESR2, which is the first ESR2 cloned from a raptor species, was greater than that of ESR1. Significant activation of both condor ESRs by EDCs occurred at high concentrations (≥1μM), which are within the range of plasma levels of certain EDCs (eg, dichlorodiphenyldichloroethylene [p'p-DDE]) in coastal-dwelling condors. Finally, phylogenetic analyses of ESRs of 41 avian species identified a single amino acid position in ESR2 under positive selection. Mutation of this amino acid affected receptor activation by EDCs, suggesting the identity of this amino acid may influence EDC sensitivity of avian species. Together, these findings broaden our understanding of EDC interactions with ESRs in avian species. For condors specifically, these data could be used to evaluate EDC exposure risk at future release sites to identify those least likely to compromise the continued recovery of this species.

Brassica seed meal soil amendments transform the rhizosphere microbiome and improve apple production through resistance to pathogen reinfestation

Brassicaceae seed meal (SM) formulations were compared with preplant 1,3-dichloropropene/chloropicrin (Telone-C17) soil fumigation for the ability to control apple replant disease and to suppress pathogen or parasite reinfestation of organic orchard soils at two sites in Washington State. Preplant soil fumigation and an SM formulation consisting of either Brassica juncea-Sinapis alba or B. juncea-B. napus each provided similar levels of disease control during the initial growing season. Although tree growth was similar in fumigated and SM-amended soil during the initial growing season, tree performance in terms of growth and yield was commonly superior in B. juncea-S. alba SM-amended soil relative to that in fumigated soil at the end of four growing seasons. SM-amended soils were resistant to reinfestation by Pratylenchus penetrans and Pythium spp. relative to fumigated soils and corresponded with enhanced tree performance. Phytotoxic symptoms were observed in response to SM amendment at one of two orchard sites, were dependent upon season of application, and occurred in an SM formulation-specific manner. After 2 years, the rhizosphere microbiome in fumigated soils had reverted to one that was indistinguishable from the no-treatment control. In contrast, rhizosphere soils from the SM treatment possessed unique bacterial and fungal profiles, including specific microbial elements previously associated with suppression of plant-pathogenic fungi, oomycetes, and nematodes. Overall diversity of the microbiome was reduced in the SM treatment rhizosphere, suggesting that enhanced "biodiversity" was not instrumental in achieving system resistance or pathogen suppression.

Laboratory Studies of Aedes aegypti Attraction to Ketones, Sulfides, and Primary Chloroalkanes Tested Alone and in Combination with L-Lactic Acid

The attraction of female Aedes aegypti to single compounds and binary compositions containing L-lactic acid and an additional saturated compound from a set of ketones, sulfides, and chloroalkanes was studied using a triple-cage dual-port olfactometer. These chemical classes were studied because of their structural relation to acetone, dimethyl disulfide, and dichloromethane, which have all been reported to synergize attraction to L-lactic acid. Human odors, carbon dioxide, and the binary mixture of L-lactic acid and CO₂served as controls for comparison of attraction responses produced by the binary mixtures. All tested mixtures that contained chloroalkanes attracted mosquitoes at synergistic levels, as did L-lactic acid and CO₂. Synergism was less frequent in mixtures of L-lactic acid with sulfides and ketones; in the case of ketones, synergistic attraction was observed only for L-lactic acid combined with acetone or butanone. Suppression or inhibition of attraction response was observed for combinations that contained ketones of C7-C12 molecular chain length (optimum in the C8-C10 range). This inhibition effect is similar to that observed previously for specific ranges of carboxylic acids, aldehydes, and alcohols.

Dioxins and dioxin-like compounds in composts and digestates from European countries as determined by the in vitro bioassay and chemical analysis

Aerobic composting and anaerobic digestion plays an important role in reduction of organic waste by transforming the waste into humus, which is an excellent soil conditioner. However, applications of chemical-contaminated composts on soils may have unwanted consequences such as accumulation of persistent compounds and their transfer into food chains. The present study investigated burden of composts and digestates collected in 16 European countries (88 samples) by the compounds causing dioxin-like effects as determined by use of an in vitro transactivation assay to quantify total concentrations of aryl hydrocarbon receptor-(AhR) mediated potency. Measured concentrations of 2,3,7,8-Tetrachlorodibeno-p-dioxin (2,3,7,8-TCDD) equivalents (TEQbio) were compared to concentrations of polycyclic aromatic hydrocarbons (PAHs) and selected chlorinated compounds, including polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), co-planar polychlorinated biphenyls (PCBs), indicator PCB congeners and organochlorine pesticides (OCPs). Median concentrations of TEQbio (dioxin-like compounds) determined by the in vitro assay in crude extracts of various types of composts ranged from 0.05 to 1.2 with a maximum 8.22μg (TEQbio)kg(-1) dry mass. Potencies were mostly associated with less persistent compounds such as PAHs because treatment with sulfuric acid removed bioactivity from most samples. The pan-European investigation of contamination by organic contaminants showed generally good quality of the composts, the majority of which were in compliance with conservative limits applied in some countries. Results demonstrate performance and added value of rapid, inexpensive, effect-based monitoring, and points out the need to derive corresponding effect-based trigger values for the risk assessment of complex contaminated matrices such as composts.

Chlorinated polyketide obtained from a Daldinia sp. treated with the epigenetic modifier suberoylanilide hydroxamic acid

A new chlorinated pentacyclic polyketide, daldinone E (1), was purified from a Daldinia sp. fungal isolate treated with the epigenetic modifier suberoylanilide hydroxamic acid (SAHA). A biosynthetically related epoxide-containing daldinone analogue, 2, was also purified from the same fungus. The structures of both compounds were established by spectroscopic methods, and the absolute configurations were assigned by analysis of their NMR data (coupling constants and ROESY correlations) and DFT calculations of specific rotations and ECD spectra. During the course of these studies it was determined that metabolite 2 and the previously reported daldinone B shared the same spectroscopic data, leading to a revision of the reported structure. Both compounds 1 and 2 also exhibited DPPH radical scavenging activities with potency comparable to the positive control ascorbic acid.

Socially responsive effects of brain oxidative metabolism on aggression

Despite ongoing high energetic demands, brains do not always use glucose and oxygen in a ratio that produces maximal ATP through oxidative phosphorylation. In some cases glucose consumption exceeds oxygen use despite adequate oxygen availability, a phenomenon known as aerobic glycolysis. Although metabolic plasticity seems essential for normal cognition, studying its functional significance has been challenging because few experimental systems link brain metabolic patterns to distinct behavioral states. Our recent transcriptomic analysis established a correlation between aggression and decreased whole-brain oxidative phosphorylation activity in the honey bee (Apis mellifera), suggesting that brain metabolic plasticity may modulate this naturally occurring behavior. Here we demonstrate that the relationship between brain metabolism and aggression is causal, conserved over evolutionary time, cell type-specific, and modulated by the social environment. Pharmacologically treating honey bees to inhibit complexes I or V in the oxidative phosphorylation pathway resulted in increased aggression. In addition, transgenic RNAi lines and genetic manipulation to knock down gene expression in complex I in fruit fly (Drosophila melanogaster) neurons resulted in increased aggression, but knockdown in glia had no effect. Finally, honey bee colony-level social manipulations that decrease individual aggression attenuated the effects of oxidative phosphorylation inhibition on aggression, demonstrating a specific effect of the social environment on brain function. Because decreased neuronal oxidative phosphorylation is usually associated with brain disease, these findings provide a powerful context for understanding brain metabolic plasticity and naturally occurring behavioral plasticity.

Spiromastixones A-O, antibacterial chlorodepsidones from a deep-sea-derived Spiromastix sp. fungus

Fifteen new depsidone-based analogues named spiromastixones A-O (1-15) were isolated from the fermentation broth of a deep-sea Spiromastix sp. fungus. Their structures were elucidated on the basis of extensive NMR and mass spectroscopic analysis in association with chemical conversion. Spiromastixones A-O are classified into two subtypes based on the orientation of ring C relative to ring A, while the n-propyl substituents on rings A and C are rarely seen in natural products. Most analogues are substituted by various numbers of chlorine atoms. All compounds exhibited significant inhibition against Gram-positive bacteria including Staphylococcus aureus, Bacillus thuringiensis, and Bacillus subtilis with MIC values ranging from 0.125 to 8.0 μg/mL. In addition, compounds 6-10 displayed potent inhibitory effects against methicillin-resistant bacterial strains of S. aureus (MRSA) and S. epidermidis (MRSE), while 10 also inhibited the growth of the vancomycin-resistant bacteria Enterococcus faecalis and E. faecium (VRE). The structure-activity relationships are discussed.

Evaluation of chloropicrin as a soil fumigant against Ralstonia solanacarum in ginger (Zingiber officinale Rosc.) production in China

BACKGROUND

Chloropicrin (Pic) offers a potential alternative to methyl bromide (MB) against Ralstonia solanacarum in ginger (Zingiber officinale Rosc.) production. MB is scheduled to be withdrawn from routine use by 2015 in developing countries.

METHODS

Pic treatments were evaluated in a laboratory study and in three commercial ginger fields.

RESULTS

Laboratory studies showed that the EC50 value and EC80 value of Pic were 2.7 and 3.7 mg a.i. kg-1 soil, respectively. Field trials in highly infested soil revealed that treatments of Pic at the dose of 50 g m-2 covered with totally impermeable film (TIF) or polyethylene film (PE) sharply reduced Ralstonia solanacarum and maintained high ginger yields. Both of the Pic treatments provided results similar to, or in some cases slightly lower than, MB with respect to Ralstonia solanacarum control, plant survival, plant growth and yield. All of the fumigant treatments were significantly better than the non-treated control.

CONCLUSIONS

The present study confirms that the Pic is a promising alternative with good efficacy against Ralstonia solanacarum for ginger production and could be used in integrated pest management programs in China.

Chlorinated coumarins from the polypore mushroom Fomitopsis officinalis and their activity against Mycobacterium tuberculosis

An EtOH extract of the polypore mushroom Fomitopsis officinalis afforded two new naturally occurring chlorinated coumarins, which were identified as the previously synthesized compounds 6-chloro-4-phenyl-2H-chromen-2-one (1) and ethyl 6-chloro-2-oxo-4-phenyl-2H-chromen-3-carboxylate (2). The structures of the two isolates were deduced by ab initio spectroscopic methods and confirmed by chemical synthesis. In addition, an analogue of each was synthesized as 7-chloro-4-phenyl-2H-chromen-2-one (3) and ethyl 7-chloro-2-oxo-4-phenyl-2H-chromen-3-carboxylate (4). All four compounds were characterized physicochemically, and their antimicrobial activity profiles revealed a narrow spectrum of activity with lowest MICs against the Mycobacterium tuberculosis complex.

Effect of films on 1,3-dichloropropene and chloropicrin emission, soil concentration, and root-knot nematode control in a raised bed

Soil fumigation is an important component of U.S. agriculture, but excessive emissions can be problematic. The objective of this study was to determine the effects of agricultural films (e.g., tarps) on soil fumigant atmospheric emissions and spatiotemporal distributions in soil, soil temperature, and plant pathogen control in the field using plastic films with various permeabilities and thermal properties. A reduced rate of 70% InLine (60.8% 1,3-dichloropropene (1,3-D) and 33.3% chloropicrin (CP)) was applied via drip line to raised soil beds covered with standard high-density polyethylene film (HDPE), thermic film (Thermic), or virtually impermeable film (VIF). 1,3-D and CP emission rates were determined using dynamic flux chambers, and the concentrations in soil were measured using a gas sampler. The pest control efficacy for the three treatments was determined using bioassay muslin bags containing soil infested with citrus nematodes (Tylenchulus semipenetrans). The results show that the Thermic treatment had the highest emission rates, followed by the HDPE and VIF treatments, and the soil concentrations followed the reverse order. In terms of pest control, covering the beds with thermic film led to sufficient and improved efficacy against citrus nematodes compared to standard HDPE film. Under HDPE, >20% of nematodes survived in the soil at 30 cm depth at day 12. The VIF treatment substantially reduced the emission loss from the bed (2% of the Thermic and 6% of the HDPE treatments) and eliminated plant parasitic nematodes because of its superior ability to entrap fumigant and heat within soils. The findings imply that not only the film permeability but also the synergistic ability to entrap heat should be considered in the development of new improved films for fumigation.

Ligerin, an antiproliferative chlorinated sesquiterpenoid from a marine-derived Penicillium strain

A new chlorinated sesquiterpenoid analogue of fumagillin, ligerin (1), was isolated from a marine-derived strain of Penicillium, belonging to the subgenus Penicillium, along with the known compounds penicillic acid (2), orcinol, and orsellinic acid. Chemical structures were established by an interpretation of spectroscopic data including IR, UV, and HRESIMS, together with analyses of 1D and 2D NMR spectra and X-ray analysis for the determination of the absolute configuration. Ligerin (1) displayed strong inhibitory activity against an osteosarcoma cell line. This is the first report of the isolation of a fumagillin analogue from a marine-derived Penicillium strain.

Halogenated anthraquinones from the marine-derived fungus Aspergillus sp. SCSIO F063

Metabolomic investigations focusing on the marine-derived fungus Aspergillus sp. SCSIO F063 have unveiled seven new chlorinated anthraquinones (1-7) related to averantin, together with five known analogues (11-15) when the fungus was fermented using sea salt-containing potato dextrose broth. Through the addition of sodium bromide to the broth, two new brominated anthraquinones (8, 9) and one new nonhalogenated anthraquinone (10) were obtained from the fungal mycelia. Their structures were elucidated by extensive spectroscopic analyses including MS and 1D and 2D NMR data. One metabolite, 6-O-methyl-7-chloroaveratin (2), displayed inhibition activity against three human tumor cell lines, SF-268, MCF-7, and NCI-H460, with IC(50) values of 7.11, 6.64, and 7.42 μM, respectively.

Organochlorine pesticide, endosulfan induced cellular and organismal response in Drosophila melanogaster

The effect of endosulfan (0.02-2.0μgmL(-1)) to Drosophila melanogaster (Oregon R(+)) at the cellular and organismal levels was examined. Third instar larvae of D. melanogaster and the strains transgenic for hsp70, hsp83 and hsp26 were exposed to endosulfan through food for 12-48h to examine the heat shock proteins (hsps), reactive oxygen species (ROS) generation, anti-oxidant stress markers and xenobiotic metabolism enzymes. We observed a concentration- and time-dependent significant induction of only small hsps (hsp23>hsp22) in the exposed organism in concurrence with a significant induction of ROS generation, oxidative stress and xenobiotic metabolism markers. Sub-organismal response was to be propagated towards organismal response, i.e., delay in the emergence of flies and decreased locomotor behaviour. Organisms with diminished locomotion also exhibited significantly lowered acetylcholinesterase activity. A significant positive correlation observed among ROS generation and different cellular endpoints (small hsps, oxidative stress markers, cytochrome P450 activities) in the exposed organism indicate a modulatory role of ROS in endosulfan-mediated cellular toxicity. The study thus suggests that the adverse effects of endosulfan in exposed Drosophila are manifested both at cellular and organismal levels and recommends Drosophila as an alternative animal model for screening the risk caused by environmental chemicals.

Chlorinated englerins with selective inhibition of renal cancer cell growth

The chlorinated englerins (3-9) were isolated from Phyllanthus engleri and shown to selectively inhibit the growth of renal cancer cells. The compounds were shown to be extraction artifacts produced by exposure to chloroform decomposition products during their isolation. The most active compound, 3, was synthesized from englerin A (1).

Differential inflammatory responses triggered by toxic small molecules

PURPOSE

The aim of this study is to determine whether exposure to hazardous chemicals alters chemokine or cytokine production in macrophages and link these events to changes in intracellular signaling pathways and activation of specific gene promoters.

METHODS

RAW 264.7 mouse macrophages were treated with selected toxic industrial chemicals (TICs) and examined for changes in immune function. Luminex multiplex technology was used to assess changes in cytokine/chemokine expression and activation of kinase signaling pathways. In addition, a panel of macrophage cell lines with promoter-specific luciferase reporter genes were generated and treated with the TICs, and transcriptional responses to these chemicals were detected by changes in luminescence.

RESULTS

Changes in expression of cytokines and chemokines were linked to changes in the activation state of intracellular signaling pathways. Overall, the findings reveal that sublytic levels of TICs can alter the profile of cytokines and chemokines expressed by macrophages, with a pattern that suggests immunosuppression. The data demonstrate that critical changes in immune function correlate with activation of kinase signaling pathways in macrophages.

CONCLUSIONS

These data provide insight into the effects of sublytic doses of selected TICs on macrophage function, with a particular emphasis on identifying changes in expression of cytokines and chemokines. These altered patterns in immune function were linked to changes in the activation state of intracellular signaling pathways. The data strongly suggest that small amounts of TICs can have subtle, yet very critical, effects on macrophages.

Physical and physicochemical factors effecting transport of chlorohydrocarbon gases from lung alveolar air to blood as measured by the causation of narcosis

This systematic investigation examines gas transport in the lung for two sets of chlorohydrocarbons (CHCs): the chloromethanes (C1) and chloroethanes (C2). The C1 series includes chloromethane, methylene chloride, chloroform, and carbon tetrachloride, and the C2 series includes chloroethane, 1,2-dichloroethane, 1, 1, 2-trichloroethane, and 1, 1, 2, 2-tetrachloroethane. Most CHC gases cause narcosis. The comprehensive narcosis work of Lehmann and colleagues on CHCs was used as a basis for the narcosis endpoint in the present examination. The sites for narcosis are located in the brain (midline cortex and posterior parietal area), the spine, and at many peripheral nerve sites. Central nervous system (CNS) exposure executes a multisite, neural transmission set of inhibitions that promotes rapid loss of consciousness, sensory feeling, and current and stored memory while providing temporary amnesia. Absorption into the system requires dissolution into many lipid membranes and binding to lipoproteins. Lipophilicity is a CHC property shared with many anesthetics according to the Meyer-Overton Rule. Many structurally different lipid chemicals produce the narcosis response when the lipid concentration exceeds -67 mM. This suggests narcotic or anesthetic dissolution into CNS membranes until the lipid organization is disrupted or perturbed. This perturbation includes loading of Na(+)- and K(+)-channel transmembrane lipoprotein complexes and disrupting their respective channel functional organizations. The channel functions become attenuated or abrogated until the CHC exposure ceases and CHC loading reverses. This investigation demonstrates how the CHC physical and chemical properties influence the absorption of these CHCs via the lung and the alveolar system on route to the blood. Narcosis in test animals was used here as an objective biological endpoint to study the effects of the physical factors Bp, Vp, Kd (oil: gas) partition, Henry's constant (HK), and water solubility (S%) on gas transport. Narcosis is immediate after gas exposure and requires no chemical activation only absorption into the blood and circulation to CNS narcotic sites. The three physical factors Bp, K(d) (oil: air), and S% vary directly with unitary narcosis (UN) whereas Vp and HK vary inversely with UN in linear log-log relationships for the C2 series but not for the C1 series. Physicochemical properties of C1 series gases indicate why they depart from what is usually assumed to be an Ideal Gas. An essential discriminating process in the distal lung is the limiting alveolar film layer (AFL) and the membrane layer of the alveolar acini. The AFL step influences gas uptake by physically limiting the absorption process. Interaction with and dissolution into aqueous solvent of the AFL is required for transport and narcotic activity. Narcotics or anesthetics must engage the aqueous AFL with sufficient strength to allow transport and absorption for downstream CNS binding. CHCs that do not engage well with the AFL are not narcotic. Lipophilicity and amphipathicity are also essential solvency properties driving narcotics' transport through the alveolar layer, delivery to the blood fats and lipoproteins, and into critical CNS lipids, lipoproteins, and receptor sites that actuate narcosis. AFL disruption is thought to be strongly related to a number of serious pulmonary diseases such acute respiratory distress syndrome, infant respiratory distress syndrome, emphysema, chronic obstructive pulmonary disease, asthma, chronic bronchitis, pneumonia, pulmonary infections, and idiopathic pulmonary fibrosis. The physical factors (Bp, Vp, Kd [oil: gas] partition, Henry's constant, and water solubility [S%]) combine to affect a specific transport through the AFL if lung C > C(0) (threshold concentration for narcosis). The degree of blood CHC absorption depends on dose, lipophilicity, and lung residence time. AFL passage can be manipulated by physical factors of increased pressure (kPa) or increased gas exposure (moles). Molecular lipophilicity facilitates narcosis but lipophilicity alone does not explain narcosis. Vapor pressure is also required for narcosis. Narcotic activity apparently requires stereospecific processing in the AFL and/or down-stream inhibition at stereospecific lipoproteins at CNS inhibitory sites. It is proposed that CHCs likely cannot proceed through the AFL without perturbation or disruption of the integrity of the AFL at the alveoli. CHC physicochemical properties are not expected to allow their transport through the AFL as physiological CO(2) and O(2) naturally do in respiration. This work considers CHC inspiration and systemic absorption into the blood with special emphasis on the CHC potential perturbation effects on the lipid, protein liquid layer supra to the alveolar membrane (AFL). A heuristic gas transport model for the CHCs is presented as guidance for this examination. The gas transport model can be used to study absorption for other gas delivery endpoints of environmental concern such as carcinogens.