Homologue Patterns Research Articles

Polychlorinated biphenyls in two typical landforms of Southern Anhui province, China: Sources, air-soil exchange, and risk assessment

Polychlorinated biphenyls (PCBs) were detected in the atmosphere and soil of Southern Anhui, China. The average concentration of ∑26PCBs in the atmosphere along the Yangtze River (YR) was 32 pg m−3, and was higher than that in the HuangShan Mountain (HM) which was 17 pg m−3. The average soil concentrations of ∑26PCBs along the YR and in the HM were 1.6 and 1.3 ng g−1, respectively. The mean percentages of tri-CBs were less than 40% in both air and soil samples. The percentages of penta- and hexa-CBs in air and soil samples were relatively higher than those in Chinese commercial PCBs and unintentionally produced PCBs. These homologue patterns indicated that PCBs in the environmental matrices of Southern Anhui might originate from other distant sources. In southern Anhui, most highly chlorinated congeners presented net gaseous deposition from air to soil, while lower chlorinated congeners preferred net volatilization from soil to air. PCBs in the environmental matrices of the HM were diluted with increasing altitude, suggesting that PCBs in this region might origin from some external sources, and be transported to the HM by atmosphere. Half of the sampling sites along the YR and one site in the HM had the cancer risks for ∑26PCBs through the inhalation exposure higher than acceptable risk level of 10−6. Only one sampling site had the cancer risk for ∑26PCBs through the accidental soil ingestion >10−6.

Homologue distribution patterns of 2,3,7,8-chloro-substituted PCDD/F in Bavarian soils

BackgroundSoil-background values of PCDD/F concentrations are usually conveniently displayed as toxic equivalent (TEq), being a bulk parameter of all relevant 7 PCDD- and 10 PCDF-congeneres, chloro-subsidized at the 2nd, 3rd, 7th and 8th carbon atom. Data here are ample, not so survey on congenere/homologue patterns occurring in soils. The sufficient number of samples taken within this analysis allowed first a well-grounded evaluation.ResultsOCDD proved to be the dominant congenere in all samples (forest and agriculture), however, in considerably different concentrations. As expected, highest level was detected in forest organic layers, followed by forest top soils, cropland- and grassland top soils. Although highest in concentration, OCDD only contributes to 0.17% (both forest organic- and top soil layer), respectively, 0.4% (cropland) and 0.3% (grassland) to TEq. The influence of lower chlorinated homologues on TEq is strongest in forest top soils (72%) followed by 67% (forest organic layers), cropland top soil (63%) and grassland (61%). Although all homologue patterns (forest and agriculture) give a fairly similar picture, a test of significance (χ2) proved a different population of forest samples.ConclusionsThe resemblance of the homologue patterns throughout all utilization suggests that agent levels are explained mainly by diffuse atmospheric depositions rather than by specific land use input.

Karyotyping of Amoeba proteus

In this paper, the protocol which we have developed to get satisfactory spreads of Amoeba proteus mitotic chromosomes is presented, and the process of karyotyping this amoeba species is described. This protocol allows obtaining of extended chromosomic with repeatable chromomeres pattern in individual chromosomes. We have shown that metaphase in «B»-strain amoebae (one of the type strains of A. proteus in the Amoebae Strains Collection at the Institute of Cytology) contains 27 chromosome pairs with homologous chromomeric pattern. It is ascertained that chromomeric pattern is chromosome-specific feature. The bank of images of DAPI- and YoYo1-banded individual metaphase chromosomes of «B»-strain of A. proteus is presented.

Polychlorinated biphenyls in the surrounding of an e-waste recycling facility in North-Rhine Westphalia: Levels in plants and dusts, spatial distribution, homologue pattern and source identification using the combination of plants and wind direction data

During this study the occurrence of polychlorinated biphenyls (PCBs) in the surrounding of an e-waste recycling facility in North-Rhine Westphalia was analysed. PCB levels were analysed in curly kale, spruce needles, street dusts and dusts. Conspicuously high PCB concentrations in curly kale and spruce needles were found directly northwards of the industrial premises. Furthermore a concentration gradient originating from the industrial premises to the residential areas in direction southwest to northeast was evident. Homologue patterns of highly PCB contaminated dusts and street dusts were comparable to the homologue patterns of PCB in curly kale and spruce needles. This corroborates the suspicion that the activities at the e-waste recycling facility were responsible for the elevated PCB levels in curly kale and spruce needles. The utilization of multiple linear regression of wind direction data and analysed PCB concentrations in spruce needles proved that the e-waste recycling facility caused the PCB emissions to the surrounding. Additionally, this evaluation enabled the calculation of source specific accumulation constants for certain parts of the facility. Consequently the different facility parts contribute with different impacts to the PCB levels in bioindicators.

A novel approach for acid mine drainage pollution biomonitoring using rare earth elements bioaccumulated in the freshwater clam Corbicula fluminea

Lanthanide series have been used as a record of the water–rock interaction and work as a tool for identifying impacts of acid mine drainage (lixiviate residue derived from sulphide oxidation). The application of North-American Shale Composite-normalized rare earth elements patterns to these minority elements allows determining the origin of the contamination. In the current study, geochemical patterns were applied to rare earth elements bioaccumulated in the soft tissue of the freshwater clam Corbicula fluminea after exposure to different acid mine drainage contaminated environments.Results show significant bioaccumulation of rare earth elements in soft tissue of the clam after 14 days of exposure to acid mine drainage contaminated sediment (ΣREE=1.3–8μg/gdw). Furthermore, it was possible to biomonitor different degrees of contamination based on rare earth elements in tissue. The pattern of this type of contamination describes a particular curve characterized by an enrichment in the middle rare earth elements; a homologous pattern (EMREE=0.90) has also been observed when applied NASC normalization in clam tissues. Results of lanthanides found in clams were contrasted with the paucity of toxicity studies, determining risk caused by light rare earth elements in the Odiel River close to the Estuary. The current study purposes the use of clam as an innovative “bio-tool” for the biogeochemical monitoring of pollution inputs that determines the acid mine drainage networks affection.

A novel atmospheric pressure photoionization – Mass spectrometry (APPI-MS) method for the detection of polychlorinated dibenzo P- dioxins and dibenzofuran homologues in real environmental samples collected within the vicinity of industrial incinerators

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were monitored in air, soil and vegetation (biota) samples within the vicinity of a solid waste incineration facility located in central Spain. Measurements were made monthly for a one year period. The analyses were carried out using a novel, low flow atmospheric pressure photoionization – mass spectrometry (APPI-MS) method. This technique delivers unique advantages in terms of sensitivity, cost and throughput, with detection limits approaching 1 picogram and an analysis time of 2min. Memory effects were considerable on this first prototype, limiting a final throughput of 4 samples per hour. PCDD and PCDF homologue patterns were observed for each of the air, soil and vegetation samples, and the results obtained were consistent with other studies related to the analysis of incinerator emissions.

Long-term changes in distributions of dioxin-like and estrogenic compounds in sediments of Lake Sihwa, Korea: Revisited mass balance

In the late 1990s, severe pollution by persistent organic contaminants (POCs) was observed in Lake Sihwa by use of a combination of instrumental analyses and in vitro bioassays. To determine long-term changes (>15-year gaps) in distributions of POCs and their potential toxic potencies in the given region, sediment assessments were reconducted. Target chemicals include polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and recently reported emerging chemicals, styrene oligomers (SOs). We employed in vitro bioassays (such as H4IIE-luc and MVLN) to determine potential sediment toxicities. The reduction rates of mean concentrations of APs and SOs in sediments between the two sampling years (1998 vs. 2015) were estimated to be 99% and 67%, respectively. Although APs and SOs significantly declined over the 15-year period, concentrations of PAHs were consistent. Results of the bioassays were consistent with the instrumental data, with relatively great concentrations of all target compounds being detected, particularly in inland creeks. Compositions of all target compounds exhibited changes in homologue patterns over the 15 years considered. This result indicated varying and/or continuing sources in this region. In particular, PAHs were dominated by higher-molecular-weight PAHs (e.g., benzo[g,h,i]perylene and benzo[b]fluoranthene) in recent years. This result might indicate consumption of oil-related fuels. Quantitative potency balance analysis revealed that concentrations of instrumentally-derived equivalents accounted for as little as 18.5% of bioassay-derived equivalents, which indicated significant amounts of unknown and/or unmeasured compounds were present. The present study documented the continuing severe pollution by selected POCs in the Lake Sihwa region over the last 15 years, indicating a lack of management in the area studied.

Occurrence, homologue patterns and source apportionment of short- and medium-chain chlorinated paraffins in suburban soils of Shanghai, China

In order to systematically investigate the spatial distribution, homologue profiles, and sources of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in suburban soils in Shanghai, SCCPs and MCCPs in soils were analyzed using gas chromatography coupled with low resolution mass spectrometry in electron capture negative ion (ECNI) mode (GC-ECNI-MS). The CP concentrations in soils were between not detected (ND) – 697 ng g−1 with a median value of 3.52 ng g−1 for SCCPs, and ND – 666 ng g−1 with a median value of 15.3 ng g−1 for MCCPs, respectively. The concentrations of MCCPs in most soils were higher than that of SCCPs. The total CP concentrations (sum of SCCPs and MCCPs) in soils varied from ND to 964 ng g−1 with a median value of 20.5 ng g−1. The concentration of MCCPs was higher than that of SCCPs in most soils. The levels of SCCPs and MCCPs in suburban soils in Shanghai were at the medium level when compared to other areas around the world. No significant correlation was observed between soil CP concentrations and total organic carbon contents (p > 0.05). For different use type of soils, the median concentrations of CPs in soils were found higher in greenland than that in other areas probably due to busy traffic, sewage sludge application and/or wastewater irrigation. All soils were divided into two groups by hierarchical cluster analysis (HCA) both for SCCPs and MCCPs. Three discharge sources of CPs in suburban soil of Shanghai were identified by PMF model.

Concentration and distribution of polychlorinated biphenyls in rice paddy soils

To monitor and evaluate the risk of polychlorinated biphenyls (PCBs) contamination in Pohang, Korea, the concentration and distribution of 29 PCBs in paddy soils were determined using high-resolution gas chromatography/high-resolution mass spectrometry. The overall concentrations of Σ29 PCBs in the paddy soils of the areas close to the heavily industrial city of Pohang (268–1833 pg g−1 dw) were higher than those in the paddies from Anseong (106.6–222.6 pg g−1 dw) in Korea. In Pohang, the major contributors to the Σ29 PCBs were the non-dioxin-like PCBs, including the PCBs 28, 52, 70, 101, 118, 138, 153, and 180, which correspond to 48–62% of the total PCBs. The toxic equivalency (TEQ) values obtained from the 12 dioxin-like PCBs from Pohang (0.03–1.03 pg TEQ g−1 dw) showed that PCB 126 contributed the highest toxicity, possibly posing a risk to the living organisms. The results of both principal component and cluster analysis based on the PCB homologue patterns demonstrated that each sampling site showed a similar PCBs contamination pattern, and Aroclor 1254, which is likely used by small and big steel factories, was identified as a major source of PCB contamination in Pohang.

Insight into SNPs and epitopes of E protein of newly emerged genotype-I isolates of JEV from Midnapur, West Bengal, India

BackgroundJapanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes Japanese Encephalitis (JE) and Acute Encephalitis Syndrome (AES) in humans. Genotype-I (as co-circulating cases with Genotype-III) was isolated in 2010 (JEV28, JEV21) and then in 2011 (JEV45) from Midnapur district, West Bengal (WB) for the first time from clinical patients who were previously been vaccinated with live attenuated SA14-14-2 strain. We apply bioinformatics and immunoinformatics on sequence and structure of E protein for analysis of crucial substitutions that might cause the genotypic transition, affecting protein-function and altering specificity of epitopes.ResultsAlthough frequency of substitutions in E glycoprotein of JEV28, JEV21 and JEV45 isolates vary, its homologous patterns remain exactly similar as earlier Japan isolate (Ishikawa). Sequence and 3D model-structure based analyses of E protein show that only four of all substitutions are critical for genotype-I specific effect of which N103K is common among all isolates indicating its role in the transition of genotype-III to genotype-I. Predicted B-cell and T-cell epitopes are seen to harbor these critical substitutions that affect overall conformational stability of the protein. These epitopes were subjected to conservation analyses using a large set of the protein from Asian continent.ConclusionsThe study identifies crucial substitutions that contribute to the emergence of genotype-I. Predicted epitopes harboring these substitutions may alter specificity which might be the reason of reported failure of vaccine. Conservation analysis of these epitopes would be useful for design of genotype-I specific vaccine.

FoxP2 expression in an echolocating bat (Rhinolophus ferrumequinum): Functional implications

Disruption of FOXP2, a gene encoding a forkhead domain transcription factor, may cause a severe developmental disorder of verbal communication, especially vocalization. In insectivorous bats, accelerated evolution of FoxP2 supports a previously proposed hypothesis that this gene plays a role in sensorimotor coordination. In order to validate this hypothesis, it is necessary to examine the expression of FoxP2 in the relevant sensorimotor structures involved in echolocation behavior. Here, we present the detailed spatial expression pattern of FoxP2 in the mature brain of Rhinolophus ferrumequinum using immunohistochemistry. FoxP2 expression was found in many regions of the bat brain. The homologous pattern of FoxP2 expression in this bat argues for the role of the gene in motor-related circuits. In addition, FoxP2 was strongly expressed in many regions related to echolocation such as the inferior colliculus, superior colliculus, periaqueductal gray, paralemniscal nucleus, nuclei of the lateral lemniscus, parabrachial nucleus and ambiguous nucleus. Overall, our findings imply that FoxP2 plays an important role in echolocation.

Abstract P2-03-11: Genomic pattern of breast carcinomas carrying mutations of non-BRCA homologous recombination genes

Abstract Background BRCA1 and BRCA2 are involved in the homologous recombination (HR) double-strand DNA break repair and genomic patterns of breast tumors with defective BRCA are characterized by increased genomic instability. The pre-clinical and clinical studies show that tumors with defective BRCA or other HR genes can response to platinum and PARP inhibitors. However, the genomic pattern of tumors carrying mutations of non-BRCA HR genes are not investigated. Methods Genomic patterns of breast carcinomas were performed by comparative genomic hybridization (CGH) array containing 60000 probes covering the whole genome with an average spacing of 40kb. The frequency of gains and losses for each regions detected by probes was calculated by ratio thresholds of 0.25 and -0.25, respectively. Large-scale genomic structural aberration was defined as the region of gains and losses of at least 10Mb. We analyzed the difference of large-scale aberration, including numbers, length and specific regions, between tumors with BRCA mutation (mtBRCA), non-BRCA HR mutation (mtHR) and wild type. Results We examined 41 breast carcinomas, including 15 cases with BRCA mutations, 14 with non-BRCA HR gene mutations and 12 without mutations (control). The 14 non-BRCA HR gene were 1 ATM, 1 BRIP1, 1 BARD1, 1 FANCA, 2 FANCB, 1 FANCI, 1 PALB2, 2 RAD50, 2 RAD51C and 2 RAD51D. The number and length of large-scale genomic structural aberration of mtBRCA tumors were significantly higher than wild type tumors (number p=0.005; length p=0.005), indicating CGH can distinguish the mtBRCA from control tumors. We then checked the mtHR tumors, which also revealed significantly increased number and longer length of structural aberrations compared to wild type tumors (number p=0.035; length p=0.022), but were not different from mtBRCA tumors (number p=0.204; length p=0.425). Among the specific regions on chromosomes, mtBRCA and mtHR tumors contained similar genomic aberration regions but different from wild type tumors. The most frequent aberration regions of mtBRCA and mtHR tumors are chromosome 6p22.1-p25, 6q21-q27, 8q11.1-q24, 11p11.2-p14.1, 11q, 12p and 19p, which are less revealed in the wild type (all p value <0.05). Conclusions Our study demonstrated a direct evidence that increased genomic instability were the common characteristics of mtBRCA and non-BRCA mtHR tumors. In addition, we identify the specific genomic patterns of mtBRCA and mtHR tumors, which can be a biomarker indicating HR deficiency and response to platinum and PARP inhibitors. Citation Format: Lin P-H, Kuo W-H, Wang M-Y, Lo C, Lin C-H, Lu Y-S, Chiu C-F, Huang C-S. Genomic pattern of breast carcinomas carrying mutations of non-BRCA homologous recombination genes [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-03-11.

Gas-Particle Partitioning of Polychlorinated Dibenzo-p-dioxins, Dibenzofurans, and Biphenyls in Flue Gases from Municipal Solid Waste Incinerators

Gas-particle partitioning of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and biphenyls (PCBs) was evaluated in flue gases emitted from two municipal solid waste incinerators. Total PCDD/Fs and dl-PCBs in the flue gas were presented, in decreasing order, within gas phases, particulate phases, and aqueous phases. PCDD/F concentrations in the flue gas ranged from 0.75 to 15 ng m(-3), while in the particulate phase they ranged from 0.14 to 8.1 ng m(-3). Dioxin-like (dl-) PCBs had concentrations of 0.18-28 ng m(-3) in the flue gas, and 0.041-1.3 ng m(-3) in the particulate phase. PCDD/F and dl-PCB levels were associated with specific size ranges of particles, increasing as particle size decreased. More than 54% (81%) of PCDD/Fs and 49% (79%) of dl-PCBs were associated with fine particles of less than 2.5 (10) mu m-diameter. In addition, average levels of PCDD/Fs, PCBs, and dl-PCBs were 0.15 +/- 0.11 ng m(-3), 11 +/- 11 ng m(-3), and 0.21 +/- 0.20 ng m(-3), respectively. Levels of non-2,3,7,8-chlorinated PCDD/Fs were much higher than 2,3,7,8-chlorinated PCDD/Fs in PCDD/F homologue patterns. This suggests that more attention should be paid to non-2,3,7,8-chlorinated PCDD/Fs in the environment, given their potential to transform to more toxic species.

PCDD/F Formation in Milled Fly Ash: Metal Chloride Catalysis

ABSTRACTMechanochemical treatment reduces the particle size of fly ash and disperses catalytic metals, raising the potential reactivity of fly ash to form and destroy ‘dioxins’, i.e., polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD + PCDF or PCDD/F). To test this issue, model fly ash (MFA) samples were artificially composed by mixing silica, sodium chloride, and activated carbon, and doping this matrix with five selected catalytic metal chlorides administered as CuCl2•2H2O, CrCl3•6H2O, FeCl3 (anhydrous), ZnCl2 and anhydrous CaCl2. Without additives, these samples were first finely milled for 0 (blank), 1 and 8 h, and the effect on the formation of PCDD/F was investigated during de novo tests. These simulate the conditions prevailing in deposits in the heat-recovery zone of an incinerator, where dioxins are formed and destroyed, and the tests were conducted at the same temperature, reaction time and air flow rate. Metal chlorides produce specific and distinct homologue and isomer patterns. The isomer signatures of 2,3,7,8-PCDD/F, precursor route, and other congeners were recognised and are studied in some detail. Principal component analysis (PCA) was applied to the 2,3,7,8-PCDD/F-congeners, indicating CuCl2 as major contributor of WHO2005-TEQ values. Surprisingly, for CuCl2•2H2O the total yield of dioxins reduced drastically with milling. Since this study revealed various unexpected results, as well as experimental limitations, some suggestions for further ongoing work are formulated.

Characterization ofCYCLOIDEA-like genes in Proteaceae, a basal eudicot family with multiple shifts in floral symmetry

The basal eudicot family Proteaceae (approx. 1700 species) shows considerable variation in floral symmetry but has received little attention in studies of evolutionary development at the genetic level. A framework for understanding the shifts in floral symmetry in Proteaceae is provided by reconstructing ancestral states on an upated phylogeny of the family, and homologues of CYCLOIDEA (CYC), a key gene for the control of floral symmetry in both monocots and eudicots, are characterized. Perianth symmetry transitions were reconstructed on a new species-level tree using parsimony and maximum likelihood. CYC-like genes in 35 species (31 genera) of Proteaceae were sequenced and their phylogeny was reconstructed. Shifts in selection pressure following gene duplication were investigated using nested branch-site models of sequence evolution. Expression patterns of CYC homologues were characterized in three species of Grevillea with different types of floral symmetry. Zygomorphy has evolved 10-18 times independently in Proteaceae from actinomorphic ancestors, with at least four reversals to actinomorphy. A single duplication of CYC-like genes occurred prior to the diversification of Proteaceae, with putative loss or divergence of the ProtCYC1 paralogue in more than half of the species sampled. No shifts in selection pressure were detected in the branches subtending the two ProtCYC paralogues. However, the amino acid sequence preceding the TCP domain is strongly divergent in Grevillea ProtCYC1 compared with other species. ProtCYC genes were expressed in developing flowers of both actinomorphic and zygomorphic Grevillea species, with late asymmetric expression in the perianth of the latter. Proteaceae is a remarkable family in terms of the number of transitions in floral symmetry. Furthermore, although CYC-like genes in Grevillea have unusual sequence characteristics, they display patterns of expression that make them good candidates for playing a role in the establishment of floral symmetry.

Correlation of the Native Inaba Strain With the Dominant Isolated Strains Obtained From Outbreaks in 2013 in Iran

Objective: Cholera is endemic in Iran and each year we are facing with some outbreaks throughout the country. The objective of this study was to analyze the isolated cholera strains at outbreak 2013 for studying the their similarity and compare their homology in order to find out the route of infection either emerge from abroad or reemerge from inside native strains. Methods: All diagnosed V. cholerae isolates were entered to the study after re-identification at referral laboratory of Health Ministry based on standard procedures. These specimens were examined for specific serogroups by O1 polyvalent and Ogawa/Inaba monospecific antisera and tested by MIC Test Strip Method against Ciprofloxacin, Nalidixic Acid, Cefixime, Ampicillin, Tetracycline, Trimethoprim-Sulfamethaxazone, and Erythromycin. Results: A total of 257 clinical Vibrio cholerae was isolated in an outbreak of Iran at 2013. The dominant causative type was Inaba. Vibrio cholerae was reported and isolated from 12 provinces, while 81.71% of cases from two southeast provinces. The outbreaks started from August and lasted in November. In Antibiotic susceptibility test isolates were 100% resistant to Nalidixic acid, Tetracycline and SXT while all were sensitive to Ciprofloxacin, Cefixime and Ampicillin. However, 23% of strains were sensitive to Erythromycin and all were isolated at the first two weeks of outbreak either from Iranian citizen or foreign travelers. Homology of isolates was investigated through genotyping by PFGE method and their clonality was compared with previous isolated Iranian native strain. Overall 92% of analyzed strains showed a homolog pattern. These strains were located in 8 clusters. Although isolated strains at 2011 had 80 % homology with recent isolates, located in complete distinct cluster than all strains isolated at 2013. PFGE analysis revealed no dissimilarity between those stains resistant and sensitive to Erythromycin. Conclusion: This study confirmed that isolated Inaba strains at 2013 had different clonality pattern in PFGE than previously identified, suggested have foreign route from the neighboring countries

Short-chain chlorinated paraffins in soil, paddy seeds (Oryza sativa) and snails (Ampullariidae) in an e-waste dismantling area in China: Homologue group pattern, spatial distribution and risk assessment

Short-chain chlorinated paraffins (SCCPs) in multi-environmental matrices are studied in Taizhou, Zhejiang Province, China, which is a notorious e-waste dismantling area. The investigated matrices consist of paddy field soil, paddy seeds (Oryza sativa, separated into hulls and rice unpolished) and apple snails (Ampullariidae, inhabiting the paddy fields). The sampling area covered a 65-km radius around the contamination center. C10 and C11 are the two predominant homologue groups in the area, accounting for about 35.7% and 33.0% of total SCCPs, respectively. SCCPs in snails and hulls are generally higher than in soil samples (30.4–530 ng/g dw), and SCCPs in hulls are approximate five times higher than in corresponding rice samples (4.90–55.1 ng/g dw). Homologue pattern analysis indicates that paddy seeds (both hull and rice) tend to accumulate relatively high volatile SCCP homologues, especially the ones with shorter carbon chain length, while snails tend to accumulate relatively high lipophilic homologues, especially the ones with more substituted chlorines. SCCPs in both paddy seeds and snails are linearly related to those in the soil. The e-waste dismantling area, which covers a radius of approximate 20 km, shows higher pollution levels for SCCPs according to their spatial distribution in four matrices. The preliminary assessment indicates that SCCP levels in local soils pose no significant ecological risk for soil dwelling organisms, but higher risks from dietary exposure of SCCPs are suspected for people living in e-waste dismantling area.

Concentrations and patterns of polychlorinated biphenyls at different process stages of cement kilns co-processing waste incinerator fly ash

Cement kilns can be used to co-process fly ash from municipal solid waste incinerators. However, this might increase emission of organic pollutants like polychlorinated biphenyls (PCBs). Knowledge of PCB concentrations and homolog and congener patterns at different stages in this process could be used to assess the possibility of simultaneously controlling emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and “dioxin-like” compounds. To date, emissions from cement kilns co-processing fly ash from municipal solid waste incinerators have not been analyzed for PCBs. In this study, stack gas and particulate samples from two cement kilns co-processing waste incinerator fly ash were analyzed for PCBs. The average total tri- to deca-chlorinated biphenyl (∑3–10PCB) concentration in the stack gas samples was 10.15ngm−3. The ∑3–10PCB concentration ranges in particulate samples from different stages were 0.83–41.79ngg−1 for cement kiln 1and0.13–1.69ngg−1 for cement kiln 2. The ∑3–10PCB concentrations were much higher in particulate samples from the suspension pre-heater boiler, humidifier tower, and kiln back-end bag filters than in particulate samples from other stages. For these three stages, PCBs contributed to 15–18% of the total PCB, PCDD/F, and polychlorinated naphthalene toxic equivalents in stack gases and particulate matter. The PCB distributions were similar to those found in other studies for PCDD/Fs and polychlorinated naphthalenes, which suggest that it may be possible to simultaneously control emissions of multiple organic pollutants from cement kilns. Homolog patterns in the particulate samples were dominated by the pentachlorobiphenyls. CB-105, CB-118, and CB-123 were the dominant dioxin-like PCB congeners that formed at the back-end of the cement kiln. A mass balance of PCBs in the cement kilns indicated that the total mass of PCBs in the stack gases and clinker was about half the mass of PCBs in the raw materials.

Depositional time trends of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in a dated sediment core from the Northern Arabian Gulf

The historical record of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) deposition was reconstructed from the analysis of a dated sediment core collected from a remote area in the northwestern Arabian Gulf not influenced by any point sources of contamination. The sedimentary record showed that PCDD/F concentrations started to increase above pre-industrial background levels in the mid-1960s. This was followed by an exponential increase in concentrations attaining a maximum of 7.5pg/g (dry wt) in the early 1980s and stayed fairly constant thereafter. The homolog profiles in sediments remained fairly consistent throughout the core with PCDD contributing 75% of the ΣPCDD/F concentrations. The homolog profile was dominated by OCDD which contributed approximately 55% of the total dioxins throughout the core. The consistency in the homolog patterns throughout the core suggests that the source of dioxins have remained fairly unchanged throughout the sedimentary record represented by the core.

Membrane Proteins Are Dramatically Less Conserved than Water-Soluble Proteins across the Tree of Life.

Membrane proteins are crucial in transport, signaling, bioenergetics, catalysis, and as drug targets. Here, we show that membrane proteins have dramatically fewer detectable orthologs than water-soluble proteins, less than half in most species analyzed. This sparse distribution could reflect rapid divergence or gene loss. We find that both mechanisms operate. First, membrane proteins evolve faster than water-soluble proteins, particularly in their exterior-facing portions. Second, we demonstrate that predicted ancestral membrane proteins are preferentially lost compared with water-soluble proteins in closely related species of archaea and bacteria. These patterns are consistent across the whole tree of life, and in each of the three domains of archaea, bacteria, and eukaryotes. Our findings point to a fundamental evolutionary principle: membrane proteins evolve faster due to stronger adaptive selection in changing environments, whereas cytosolic proteins are under more stringent purifying selection in the homeostatic interior of the cell. This effect should be strongest in prokaryotes, weaker in unicellular eukaryotes (with intracellular membranes), and weakest in multicellular eukaryotes (with extracellular homeostasis). We demonstrate that this is indeed the case. Similarly, we show that extracellular water-soluble proteins exhibit an even stronger pattern of low homology than membrane proteins. These striking differences in conservation of membrane proteins versus water-soluble proteins have important implications for evolution and medicine.