Comprehensive Compilation of Congener Profiles to Support Health Assessment of Environmental Exposures to Polychlorinated Biphenyl Mixtures.

Exposure to polychlorinated biphenyls (PCBs) remains a potential human health risk due to their persistence in the environment, despite a global ban on their production. Understanding the composition of PCB mixtures is essential for the application of a mixtures-based approach to assessing health risks of PCB exposure. This work represents the most extensive effort to date to compile and make publicly available the PCB congener profiles for mixtures with toxicological data, providing a foundation for understanding toxicological potency of PCB mixtures in the environment. We identified published congener profiles across 29 commercial and simulated environmental PCB mixtures, including various Aroclors, Phenoclors, Clophens, and Kanechlors, among others. A total of 117 references containing 401 distinct complete or partial tabularized profiles were found. Aroclor 1254 had the most published profiles, with 79 unique datasets characterizing multiple mixture lots. In contrast, no congener-specific composition data were identified for Fenclors, Clophen C, or Pyralenes. Eighty-seven of the most complete and clearly reported profiles underwent a detailed extraction of the congener data, PCB mixture source, and analytical methods. Challenges encountered during data extraction included congener coelutions, incomplete methods reporting, and inconsistencies in PCB nomenclature. These factors complicate data visualization, comparisons across datasets, and use of the data in subsequent analyses. Where possible, we have converted profiles to the same units and congener numbering convention to allow for easier comparison. The extracted data are publicly available online as interactive visuals and as a downloadable Microsoft Excel® workbook. This dataset provides researchers with an overview of the current PCB mixture profile landscape that can serve as a tool to support efforts to minimize the health impacts of environmental PCB exposure, including the exploration of links between mixture composition and toxicity and the identification of the most efficient and effective remediation strategies at contaminated sites.

Changes in microcystin concentration in Lake Taihu, 13 years (2007-2020) after the 2007 drinking water crisis.

Since the 2007 water crisis occurred in Lake Taihu, substantial measures have been taken to restore the lake. This study evaluates the effectiveness of these restoration activities. We examined the physicochemical parameters and the distribution of microcystin and Microcystis in both the water column and sediment during the bloom period of May 2020 to October 2020. The mean value of extracellular and intracellular microcystin content was 0.12 µg L-1 and 16.26 µg L-1, respectively. The mean value of microcystin in sediment was 172.02 ng g-1 and peaked in August. The concentration in the water and sediment was significantly lower than the historical average concentration. The abundance of toxigenic Microcystis and total Microcystis in the water column ranged from 2.61 × 102 to 2.25 × 109 copies·L-1 and 8.28 × 105 to 2.76 × 109 copies·L-1, respectively. The proportion of toxic Microcystis in the sediment ranging from 31.2% to 19.12%. The highest and lowest region was Meiliang Bay and Grass-algae type zone, respectively. The copy number of the 16S rRNA gene was 1-4 orders of magnitude higher than that of mcyA gene in populations of Microcystis, indicating that non-toxic Microcystis was the dominant form in the majority of the lake. The abundance of toxic Microcystis in the water column was positively correlated with total phosphorus, PO43--P and pH, while the water temperature played distinct role to the distribution of toxic Microcystis in sediment. Our research indicated phosphorus remains a key factor influencing the toxic Microcystis and microcystins in the water column. pH played distinct roles in the distribution of microcystins in sediment and water column. The increasing water temperature is a threat. Explicit management actions and policies, which take into account nutrient concentrations, pH, and increasing temperatures, are necessary to understand and control the distribution of microcystin and Microcystis in Lake Taihu.

Spatial distributions, behaviors, and sources of PCDD/Fs in surface water and sediment from the Yangtze River Delta.

The Yangtze River Delta (YRD), one of the most economically developed and industrialized regions in China, is confronted with challenges arising from rapid urbanization, particularly environmental pollution. The collection of surface water and sediment samples from forty-nine sites in the YRD was conducted to analyze 2378-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) congeners. The detected concentrations of PCDD/Fs were 0-5.3 pg TEQ/L in water and 0.12-1493 pg TEQ/g dw in sediment. The PCDD/Fs contamination in the sediment was widespread in the YRD. There were variations in the congener characteristics of PCDD/Fs in surface water and sediment. The proportion of OCDD was significantly lower in surface water samples compared to sediment, while the less chlorine-substituted homologs were found in larger proportions. To understand the partitioning and behavior of dioxins within the water-sediment system, we calculated the organic carbon normalized partition coefficients and fugacity fraction (ff) of PCDD/F congeners. The results revealed that the PCDD/Fs had not attained a state of distributional equilibrium, and the non-specific hydrophobic effect seemed minimally influential on their partitioning between sediment and water. The average ff values, which varied between 0.06 and 0.63, indicated differing migration directions for the PCDD/F congeners. Source identification analysis provided evidence that the dioxins in the river water were primarily attributed to industrial thermal processes. Iron and steel smelting, along with pesticide production and use, were likely responsible for the sediment contamination. This comprehensive analysis underscores the complex nature of PCDD/Fs pollution in the YRD and highlights the necessity for targeted environmental management strategies.

Insights into Full-congener Profiles of Chlorinated Benzenes in Fly and Bottom Ash: Case Study in Vietnamese Industrial and Municipal Waste Incinerators.

Chlorinated benzenes (CBzs) are a group of organic pollutants, which have been industrially or unintentionally produced through various chemical and thermal processes. Studies on full congener profiles of CBzs in waste and environmental samples are relatively limited and not updated. In the present study, concentrations of 12 CBzs were determined in fly ash (FA) and bottom ash (BA) samples collected from one municipal waste incinerator (MWI) and one industrial waste incinerator (IWI) in northern Vietnam. Levels of Σ12CBzs were higher in bottom ash (median 25.3; range 1.59-45.7 ng/g) than in fly ash (median 7.30; range 1.04-30.0 ng/g). The CBz profiles were dominated by di- and tri-chlorinated congeners with the major congeners as 1,2,4-TCB, 1,2,3-TCB, 1,2-DCB, and 1,3-DCB. However, CBz profiles varied greatly between sample types and incinerators, implying differences in input materials, formation pathways, and pollutant behaviors. Incomplete combustion is possibly responsible for high levels of CBzs in industrial bottom ash. The emission factors of Σ12CBzs ranged from 21 to 600 µg/ton for fly ash and from 190 to 4570 µg/ton for bottom ash, resulting in annual emissions of about 6 and 3 g/year for the IWI and MWI, respectively. Our results suggest additional investigations on industrial emission and environmental occurrence of all 12 CBzs rather than solely focusing on regulated congeners like hexachlorobenzene and pentachlorobenzene.

Bioaccumulation, Trophic Transfer, and Biotransformation of Polychlorinated Diphenyl Ethers in a Simulated Aquatic Food Chain.

Polychlorinated diphenyl ethers (PCDEs) are detected in aquatic environments and demonstrate adverse effects in aquatic organisms. However, data regarding the environmental behavior of PCDEs in aquatic ecosystems are lacking. In the present study, a simulated aquatic food chain (Scenedesmus obliquus-Daphnia magna-Danio rerio) was constructed in a lab setting, and the bioaccumulation, trophic transfer, and biotransformation of 12 PCDE congeners were quantitatively investigated for the first time. The log-transformed bioaccumulation factors (BCFs) of PCDEs in S. obliquus, D. magna, and D. rerio were in the range of 2.94-3.77, 3.29-4.03, and 2.42-2.89 L/kg w.w., respectively, indicating the species-specific bioaccumulation of PCDE congeners. The BCF values increased significantly with the increasing number of substituted Cl atoms, with the exception of CDE 209. The number of Cl atoms at the para and meta positions were found to be the major positive contributing factors for BCFs in the case of the same number of substituted Cl. The lipid-normalized biomagnification factors (BMFs) of S. obliquus to D. magna, D. magna to D. rerio, and the whole food chain for the 12 PCDE congeners ranged at 1.08-2.27, 0.81-1.64, and 0.88-3.64, respectively, suggesting that some congeners had BMFs comparable to PBDEs and PCBs. Dechlorination was the only metabolic pathway observed for S. obliquus and D. magna. For D. rerio, dechlorination, methoxylation, and hydroxylation metabolic pathways were observed. 1H nuclear magnetic resonance (NMR) experiments and theoretical calculations confirmed that methoxylation and hydroxylation occurred at the ortho position of the benzene rings. In addition, reliable quantitative structure-property relationship (QSPR) models were constructed to qualitatively describe the relationships between molecular structure descriptors and BCFs for PCDEs. These findings provide insights into the movement and transformation of PCDEs in aquatic ecosystems.

Spatial and temporal trends in polychlorinated naphthalenes in sediment from Ulsan and Onsan Bays of Korea: Potential sources and ecotoxicological concerns.

Few studies have been conducted on spatial and temporal trends in polychlorinated naphthalenes (PCNs) in coastal environments. Here, we describe 18 PCN congeners found in surface and dated sediment samples collected from highly industrialized bays of Korea. Measurable levels of PCN congeners were detected in all sediment samples, suggesting concurrent and historical contamination. The highest PCN concentrations were observed in sediment from rivers, streams, and the inner portions of the bays, which are surrounded by industrial complexes and commercial harbors. CNs 73, 66/67, and 52 were dominant in surface and dated sediment samples. Congener patterns and diagnostic ratios revealed that PCN contamination is originated from combustion processes and the use of polychlorinated biphenyl (PCB) technical mixtures. PCN concentrations in dated sediment increased from the 1980s to the mid-2000s and then decreased to 2015. Although the toxic equivalent (TEQ) levels of PCNs in our study did not exceed sediment quality guidelines proposed by international authorities, the cumulative risks from the TEQ concentrations of polychlorinated dibenzo-p-dioxins, furans, PCBs, and PCNs can be expected for benthic organisms.

Degradation behaviors and accumulative effects of coexisting chlorobenzene congeners on the dechlorination of hexachlorobenzene in soil by nanoscale zero-valent iron.

It is well known that many chlorinated organic pollutants can be dechlorinated by nanoscale zero-valent iron. However, in the real chlorinated organic compounds contaminated soil, the congeners of high- and low-chlorinated isomer often coexist and their dechlorination behaviors are poorly known, such as hexachlorobenzene (HCB). In this work, the degradation behaviors of three coexisting chlorobenzene congeners pentachlorobenzene (PeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) and the influence of initial pH and reaction temperature on the dechlorination of HCB in HCB-contaminated soil by nanoscale zero-valent iron were studied. The amount and extent of accumulated coexisting chlorobenzenes was analyzed under different environmental conditions. The results indicate that nanoscale zero-valent iron can improve the degradation efficiency of highly toxic chlorinated benzenes and reduce the accumulative effects of highly toxic chlorinated benzenes on dechlorination of HCB. The accumulative effects of three coexisting chlorobenzene congeners on the dechlorination of HCB were ranked as follows: 1,2,4-TCB > 1,2,4,5-TeCB > PeCB.

Sensitive and Selective Voltammetric Sensor Based on Anionic Surfactant-Modified Screen-Printed Carbon for the Quantitative Analysis of an Anticancer Active Fused Azaisocytosine-Containing Congener.

3-(4-Nitrophenyl)-8-(2,3-dimethylphenyl)-7,8-dihydroimidazo[2,1-c][1,2,4]triazin-4(6H)-one (NDIT) is one of the most promising candidates for anticancer agents. Hence, a sensitive and selective sodium dodecyl sulfate-modified screen-printed carbon sensor (SPCE/SDS) was used for its quantitative analysis. The SPCE/SDS, in contrast to the SPCE, showed excellent behavior in the electrochemical reduction of NDIT by differential-pulse adsorptive stripping voltammetry (DPAdSV). Cyclic voltammetric (CV) studies reveal an irreversible, two-stage and not purely diffusion-controlled reduction process in 0.01 M HNO3. The sensor was characterized by CV and electrochemical impedance spectroscopy (EIS). Under the optimized conditions (t 45 s, ΔE 175 mV, ν 150 mV/s, and tm 5 ms), the DPAdSV procedure with the SPCE/SDS presented a very wide linear range from 1 to 2000 nM and a low detection limit of 0.29 nM. A 1000-fold excess concentration of potential interferents commonly present in biological samples did not significantly alter the peak current of NDIT. The practical application of the proposed DPAdSV procedure with the SPCE/SDS was successfully checked by analyzing spiked human serum samples.

Modeling Postmortem Ethanol Production/Insights into the Origin of Higher Alcohols.

The forensic toxicologist is challenged to provide scientific evidence to distinguish the source of ethanol (antemortem ingestion or microbial production) determined in the postmortem blood and to properly interpret the relevant blood alcohol concentration (BAC) results, in regard to ethanol levels at death and subsequent behavioral impairment of the person at the time of death. Higher alcohols (1-propanol, 1-butanol, isobutanol, 2-methyl-1-butanol (isoamyl-alcohol), and 3-methyl-2-butanol (amyl-alcohol)) are among the volatile compounds that are often detected in postmortem specimens and have been correlated with putrefaction and microbial activity. This brief review investigates the role of the higher alcohols as biomarkers of postmortem, microbial ethanol production, notably, regarding the modeling of postmortem ethanol production. Main conclusions of this contribution are, firstly, that the higher alcohols are qualitative and quantitative indicators of microbial ethanol production, and, secondly that the respective models of microbial ethanol production are tools offering additional data to interpret properly the origin of the ethanol concentrations measured in postmortem cases. More studies are needed to clarify current uncertainties about the origin of higher alcohols in postmortem specimens.

Pollution level, spatial distribution, and congener fractionation characteristics of low-brominated polybrominated diphenyl ethers (PBDEs) in sediments around Chaohu Lake, China.

As new persistent organic compounds, polybrominated diphenyl ethers (PBDEs) have aroused important concern because of their potential bioaccumulation and possible ecological and health risk. To examine the sources and temporal variation of PBDEs in Chaohu Lake in eastern China, the surface sediments from Nanfei River (NFR) and core sediments from four estuaries were measured. It showed that low-brominated congeners were dominant, from MonoBDEs to HeptaBDEs (referred to as Σ39PBDE). Concentrations of ∑39PBDE and the ratios of (BDE-47 + BDE-99 + BDE-100)/(BDE-153 + BDE-154) were much greater in surface sediments than in core sediments. The highest concentration was observed in a site close to the outfall of a municipal sewage treatment plant (MSTP), and the ratio was significantly correlated with ∑39PBDE. These results suggested that PentaBDE and OctaBDE commercial mixtures were widely used around Chaohu Lake and the effluent of municipal sewage was a dominant source of PBDEs to surface sediment. Compared to data from other freshwater systems around the world, the concentrations of BDE-47 and BDE-99 in this study were in the middle of the range of global data, but BDE-183 concentrations were at the high end of the range. Due to restrictions on the usage of PentanBDE and OctaBDE commercial mixtures, reductions of PBDE levels from subsurface to superficial layer were observed in all estuaries. Elevated contribution by MonoBDEs to ∑39PBDE in the estuary of the only outflow river suggests significant congener fractionation. TriBDEs, TetraBDEs, and HexaBDEs appeared to pose low risks in all surface sediments, but moderate to high risks may be expected for PentaBDEs. Overall, the results would contribute to a better understanding of the sources and environmental fate of PBDEs in the studied eutrophicated lake.

Genome mining of Streptomyces sp. CB00271 as a natural high-producer of ß-rubromycin and the resulting discovery of ß-rubromycin acid.

ß-rubromycin (ß-RUB) (1) is an efficient inhibitor of human telomerase possessing a unique spiroketal moiety as a potential pharmacophore and regarded as a promising anticancer drug lead. But the development of (ß-RUB) (1) has long been hampered by its low titer and very poor water solubility. By adopting a genome mining strategy, an FAD-dependent monooxygenase RubN involving with the formation of the spiro system was applied as the probe and Streptomyces sp. CB00271 was screened out from our strain collection as an alternative natural high producer of ß-RUB (1). After a series of fermentation optimizations, CB00271 could produce 124.8 ± 3.4 mg/L ß-RUB (1), which was the highest titer up to now. Moreover, the enhanced production of ß-RUB (1) in fermentation broth also led to the discovery of a new congener ß-RUB acid (7), which was structurally elucidated as the acid form of ß-RUB (1). Comparing to ß-RUB (1), the substituted carboxyl group endowed ß-RUB acid (7) much better solubility in serum and resulted in its higher activity towards tumor cells. Our work set up a solid base for the pilot-scale production of ß-RUB (1) and its congeners to facilitate their future development as promising anticancer drug leads, and also provide an alternative and practical strategy for the exploitation of other important microbial natural products.

Non-dioxin-like polychlorinated biphenyl neurotoxic equivalents found in environmental and human samples.

Non-dioxin like polychlorinated biphenyls (NDL PCB) are recognized neurotoxicants with implications on altered neurodevelopment and neurodegeneration in exposed organisms. NDL PCB neurotoxic relative potency schemes have been developed for a single mechanism, namely activity toward the ryanodine receptor (RyR), or combined mechanisms including, but not limited to, alterations of RyR and dopaminergic pathways. We compared the applicability of the two neurotoxic equivalency (NEQ) schemes and applied each scheme to PCB mixtures found in environmental and human serum samples. A multiple mechanistic NEQ predicts higher neurotoxic exposure concentrations as compared to a scheme based on the RyR alone. Predictions based on PCB ortho categorization, versus homologue categorization, lead to a higher prediction of neurotoxic exposure concentrations, especially for the mMOA. The application of the NEQ schemes to PCB concentration data suggests that PCBs found in fish from US lakes represent a considerable NEQ exposure to fish consuming individuals, that indoor air of schools contained high NEQ concentrations representing an exposure concern when inhaled by children, and that levels already detected in the serum of adults and children may contribute to neurotoxicity. With further validation and in vivo exposure data the NEQ scheme would help provide a more inclusive measure of risk presented by PCB mixtures.

Characterizing the emissions of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) from electric arc furnaces during steel-making.

The amount of steel produced using electric arc furnaces (EAFs) has been increasing in recent years. In this study, stack gases from EAFs in steelmaking plants were analyzed to determine if they are also dominant sources of polybrominated dibenzo-p-dioxin and dibenzofuran (PBDD/F) emissions in China. Isotope dilution high-resolution gas chromatography high-resolution mass spectrometry for qualitative and quantitative analysis of PBDD/F congeners revealed that the mean PBDD/F mass concentrations were 271.1-9467.8 pg Nm-3 for the preheating stages (PS) of three EAF plants and that the corresponding toxic equivalents (TEQs) were 10.8-971.2 pg TEQ Nm-3. The PBDD/F mass concentration from the smelting stage (SS) at plant E3 was 261.9 pg Nm-3 (4.5 pg TEQ Nm-3). The PBDD/F emission factors (EF) during the preheating stage for the three plants were 0.0356-1.51 µg TEQ t-1, and the EF was 0.0359 µg TEQ t-1 during the E3 smelting stage. PBDD/Fs were found to contribute 2.39-67.85% to the total mass and 2.84-57.68% to the total dioxin TEQ. These wide fluctuations were caused by differences in the composition of feeding materials and the working temperature of bag filters. Overall, the results indicate that PBDD/F emissions from EAF steelmaking should receive increased attention. The PBDD/F congener patterns among the three EAF plants were variable, possibly because of differences in raw materials. The results presented herein will facilitate assessment of the contribution of EAFs to total PBDD/F emissions in China and investigations of PBDD/F emissions at different stages of steelmaking processes using EAFs.

Software-Assisted Pattern Recognition of Persistent Organic Pollutants in Contaminated Human and Animal Food.

Persistent Organic Pollutants (POPs) are a serious food safety concern due to their persistence and toxic effects. To promote food safety and protect human health, it is important to understand the sources of POPs and how to minimize human exposure to these contaminants. The POPs Program within the U.S. Food and Drug Administration (FDA), manually evaluates congener patterns of POPs-contaminated samples and sometimes compares the finding to other previously analyzed samples with similar patterns. This manual comparison is time consuming and solely depends on human expertise. To improve the efficiency of this evaluation, we developed software to assist in identifying potential sources of POPs contamination by detecting similarities between the congener patterns of a contaminated sample and potential environmental source samples. Similarity scores were computed and used to rank potential source samples. The software has been tested on a diverse set of incurred samples by comparing results from the software with those from human experts. We demonstrated that the software provides results consistent with human expert observation. This software also provided the advantage of reliably evaluating an increased sample lot which increased overall efficiency.

Distributions of Polychlorinated Naphthalenes in Sediments of the Yangtze River, China.

The pollution status of polychlorinated naphthalenes (PCNs) in the sediment of the Yangtze River Basin, Asia's largest river basin, was estimated. The total concentrations of PCNs (mono- to octa-CNs) ranged from 0.103 to 1.631 ng/g. Mono-, di-, and tri-PCNs-consisting of CN-1, CN-5/7, and CN-24/14, respectively, as the main congeners-were the dominant homolog groups. Combustion indicators and principal component analysis showed that the emissions from halowax mixtures were the main contributor to PCNs in sediment, among most of the sampling sites. The mean total toxic equivalent (TEQ) was calculated to be 0.045 ± 0.077 pg TEQ/g, which indicates that the PCNs in sediments were of low toxicity to aquatic organisms. This work will expand the database on the distribution and characteristics of PCNs in the river sediment of China.

Development of effective anti-influenza drugs: congeners and conjugates - a review.

Influenza is a long-standing health problem. For treatment of seasonal flu and possible pandemic infections, there is a need to develop new anti-influenza drugs that have good bioavailability against a broad spectrum of influenza viruses, including the resistant strains. Relenza™ (zanamivir), Tamiflu™ (the phosphate salt of oseltamivir), Inavir™ (laninamivir octanoate) and Rapivab™ (peramivir) are four anti-influenza drugs targeting the viral neuraminidases (NAs). However, some problems of these drugs should be resolved, such as oral availability, drug resistance and the induced cytokine storm. Two possible strategies have been applied to tackle these problems by devising congeners and conjugates. In this review, congeners are the related compounds having comparable chemical structures and biological functions, whereas conjugate refers to a compound having two bioactive entities joined by a covalent bond. The rational design of NA inhibitors is based on the mechanism of the enzymatic hydrolysis of the sialic acid (Neu5Ac)-terminated glycoprotein. To improve binding affinity and lipophilicity of the existing NA inhibitors, several methods are utilized, including conversion of carboxylic acid to ester prodrug, conversion of guanidine to acylguanidine, substitution of carboxylic acid with bioisostere, and modification of glycerol side chain. Alternatively, conjugating NA inhibitors with other therapeutic entity provides a synergistic anti-influenza activity; for example, to kill the existing viruses and suppress the cytokines caused by cross-species infection.

A Nondestructive Method to Identify POP Contamination Sources in Omnivorous Seabirds.

Persistent organic pollutants (POPs) are present in almost all environments due to their high bioaccumulation potential. Especially species that adapted to human activities, like gulls, might be exposed to harmful concentrations of these chemicals. The nature and degree of the exposure to POPs greatly vary between individual gulls, due to their diverse foraging behavior and specialization in certain foraging tactics. Therefore, in order clarify the effect of POP-contaminated areas on gull populations, it is important to identify the sources of POP contamination in individual gulls. Conventional sampling methods applied when studying POP contamination are destructive and ethically undesired. The aim of this literature review was to evaluate the potential of using feathers as a nondestructive method to determine sources of POP contamination in individual gulls. The reviewed data showed that high concentrations of PCBs and PBDEs in feathers together with a large proportion of less bioaccumulative congeners may indicate that the contamination originates from landfills. Low PCB and PBDE concentrations in feathers and a large proportion of more bioaccumulative congeners could indicate that the contamination originates from marine prey. We propose a nondestructive approach to identify the source of contamination in individual gulls based on individual contamination levels and PCB and PBDE congener profiles in feathers. Despite some uncertainties that might be reduced by future research, we conclude that especially when integrated with other methods like GPS tracking and the analysis of stable isotopic signatures, identifying the source of POP contamination based on congener profiles in feathers could become a powerful nondestructive method.

Ecological Character Displacement in Non-Congeneric Frogs.

Character displacement is phenotypic divergence driven by competition (ecological character displacement) or reproductive interference (reproductive character displacement). Although previous studies have examined these phenomena separately, recent evidence suggests that reproductive interference can drive both reproductive and ecological character displacement, in that certain traits are related to both competition and reproduction. Thus, to evaluate the effect of competition, the effect of reproductive interference must be excluded. Here, we analysed ecological character displacement between non-congeneric frogs, which show little reproductive interference. Odorrana amamiensis inhabits the Amami and Tokunoshima Islands, Japan, whereas its non-congeneric competitor Babina subaspera inhabits the Amami Island. We tested three of the Schluter (2000) criteria for ecological character displacement: phenotypic changes in O. amamiensis between the two islands, phenotypic change related to prey preference, prey availability between the two islands. We demonstrated that the three criteria in Schluter (2000) were likely to be satisfied, indicating the occurrence of ecological character displacement in non-congeners without reproductive interference. Thus, we conclude that competition is potentially the main driver of this phenotypic divergence, and that non-congeners may be a suitable model for evaluating ecological character displacement in a variety of organisms, as the influence of reproductive interference can be excluded.

Male workers' exposure characteristics of ΣPCDD/F from a municipal solid waste incinerator in south China through hair analysis.

Human hair, flue gas and fly ash from a municipal solid waste incinerator (MSWI) in south China were collected and analyzed for polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF). The ΣPCDD/F level in hair from male workers were higher than those from residents. The Principal Component Analysis (PCA) suggested that ΣPCDD/F in flue gas is an external source of male workers' hair ΣPCDD/F. Results of daily intake of ΣPCDD/F by inhaling flue gas suggested that the inhalation exposure of ΣPCDD/F was at a slight health risk. For the male workers directly exposed to the MSWI power plant, ΣPCDD/F levels in their hair were significantly higher than those who were non-directly exposed. Moreover, a significantly positive relationship was obtained between ΣPCDD/F levels in male workers' hair and the working time. The result of correlation analysis suggested that 1,2,3,4,6,7,8-HpCDD and OCDD could be level indicator congeners to estimate ΣPCDD/F levels. In addition, 2,3,7,8-TCDD could be applied as TEQ indicator congener to characterize the hair of MSWI male workers.

Total Synthesis and Antimicrobial Evaluation of 23-Demethyleushearilide and Extensive Antimicrobial Evaluation of All Synthetic Stereoisomers of (16Z,20E)-Eushearilide and (16E,20E)-Eushearilide.

A novel stereoisomer of eushearilide, 23-demethyleushearilide, was synthesized, and the structure-activity relationships of this compound along with known eushearilide stereoisomers were investigated in order to design novel lead compounds for the treatment of fungal infections. It was discovered that all of these congeners, together with the natural product, exhibited a wide range of antimicrobial activity against not only fungi but also against bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE).