Combinatorial metabolic engineering of Bacillus subtilis for de novo production of polymyxin B.

Polymyxin is a lipopeptide antibiotic that is effective against multidrug-resistant Gram-negative bacteria. However, its clinical development is limited due to low titer and the presence of homologs. To address this, the polymyxin gene cluster was integrated into Bacillus subtilis, and sfp from Paenibacillus polymyxa was expressed heterologously, enabling recombinant B. subtilis to synthesize polymyxin B. Regulating NRPS domain inhibited formation of polymyxin B2 and B3. The production of polymyxin B increased to 329.7 mg/L by replacing the native promoters of pmxA, pmxB, and pmxE with PfusA, C2up, and PfusA, respectively. Further enhancement in this production, up to 616.1 mg/L, was achieved by improving the synthesis ability of 6-methyloctanoic acid compared to the original strain expressing polymyxin heterologously. Additionally, incorporating an anikasin-derived domain into the hybrid nonribosomal peptide synthase of polymyxin increased the B1 ratio in polymyxin B from 57.5% to 62.2%. Through optimization of peptone supply in the fermentation medium and fermentation in a 5.0-L bioreactor, the final polymyxin B titer reached 962.1 mg/L, with a yield of 19.24 mg/g maltodextrin and a productivity of 10.02 mg/(L·h). This study demonstrates a successful approach for enhancing polymyxin B production and increasing the B1 ratio through combinatorial metabolic engineering.

Enhancement of polymyxin B1 production by an artificial microbial consortium of Paenibacillus polymyxa and recombinant Corynebacterium glutamicum producing precursor amino acids.

Polymyxin B, produced by Paenibacillus polymyxa, is used as the last line of defense clinically. In this study, exogenous mixture of precursor amino acids increased the level and proportion of polymyxin B1 in the total of polymyxin B analogs of P. polymyxa CJX518-AC (PPAC) from 0.15 g/L and 61.8 % to 0.33 g/L and 79.9 %, respectively. The co-culture of strain PPAC and recombinant Corynebacterium glutamicum-leu01, which produces high levels of threonine, leucine, and isoleucine, increased polymyxin B1 production to 0.64 g/L. When strains PPAC and C. glu-leu01 simultaneously inoculated into an optimized medium with 20 g/L peptone, polymyxin B1 production was increased to 0.97 g/L. Furthermore, the polymyxin B1 production in the co-culture of strains PPAC and C. glu-leu01 increased to 2.21 g/L after optimized inoculation ratios and fermentation medium with 60 g/L peptone. This study provides a new strategy to improve polymyxin B1 production.

Artificial microbial consortium producing oxidases enhanced the biotransformation efficiencies of multi-antibiotics.

Antibiotic mixtures in the environment result in the development of bacterial strains with resistance against multiple antibiotics. Oxidases are versatile that can bio-remove antibiotics. Various laccases (LACs), manganese peroxidases (MNPs), and versatile peroxidase (VP) were reconstructed in Pichia pastoris. For the single antibiotics, over 95.0% sulfamethoxazole within 48 h, tetracycline, oxytetracycline, and norfloxacin within 96 h were bio-removed by recombinant VP with α-signal peptide, respectively. In a mixture of the four antibiotics, 80.2% tetracycline and 95.6% oxytetracycline were bio-removed by recombinant MNP2 with native signal peptide (NSP) within 8 h, whereas < 80.0% sulfamethoxazole was bio-removed within 72 h, indicating that signal peptides significantly impacted removal efficiencies of antibiotic mixtures. Regarding mediators for LACs, 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) resulted in better removal efficiencies of multi-antibiotic mixtures than 1-hydroxybenzotriazole or syringaldehyde. Furthermore, artificial microbial consortia (AMC) producing LAC2 and MNP2 with NSP significantly improved bio-removal efficiency of sulfamethoxazole (95.5%) in four-antibiotic mixtures within 48 h. Tetracycline and oxytetracycline were completely bio-removed by AMC within 48 and 72 h, respectively, indicating that AMC accelerated sulfamethoxazole, tetracycline, and oxytetracycline bio-removals. Additionally, transformation pathways of each antibiotic by recombinant oxidases were proposed. Taken together, this work provides a new strategy to simultaneously remove antibiotic mixtures by AMC.

Effect of anesthesia on the outcome of high-grade glioma patients undergoing supratentorial resection: study protocol for a pragmatic randomized controlled trial.

BACKGROUND: High-grade glioma (HGG) is the most malignant brain tumor with poor outcomes. Whether anesthetic methods have an impact on the outcome of these patients is still unknown. Retrospective study has found no difference between intravenous and inhalation anesthesia on the overall survival (OS) of the HGG patients, however, intravenous anesthesia with propofol might be beneficial in a subgroup of patients with a Karnofsky Performance Status (KPS) Scale less than 80. Further prospective studies are needed to evaluate the results. METHODS: This is a single-centered, randomized controlled, parallel-group trial. Three hundred forty-four patients with primary HGG for tumor resection will be randomly assigned to receive either intravenous anesthesia with propofol or inhalation anesthesia with sevoflurane. The primary outcome is the OS of the patients within 18 months. Secondary outcomes include progression-free survival (PFS), the numerical rating scale (NRS) of pain intensity and sleep quality, the postoperative encephaloedema volume, complications, and the length of hospital stay of the patients. DISCUSSION: This is a randomized controlled trial to compare the effect of intravenous and inhalation anesthesia maintenance on the outcome of supratentorial HGG patients. The results will contribute to optimizing the anesthesia methods in these patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT02756312. Registered on 29 April 2016 and last updated on 9 Sep 2020.

Improved the lipopeptide production of Bacillus amyloliquefaciens HM618 under co-culture with the recombinant Corynebacterium glutamicum producing high-level proline.

The application of antibacterial lipopeptides is limited by high cost and low yield. Herein, the exogenous L-proline significantly improved lipopeptide production by Bacillus amyloliquefaciens HM618. A recombinant Corynebacterium glutamicum producing high levels of proline using genetically modifying proB and putA was used to establish consortium, to improve lipopeptide production of strain HM618. Compared to a pure culture, the levels of iturin A, fengycin, and surfactin in consortium reached 67.75, 39.32, and 37.25 mg L-1, respectively, an increase of 3.19-, 2.05-, and 1.63-fold over that produced by co-cultures of B. amyloliquefaciens and recombinant C. glutamicum with normal medium. Commercial amylase and recombinant Pichia pastoris with a heterologous amylase gene were used to hydrolyze kitchen waste. A three-strain consortium with recombinant P. pastoris and C. glutamicum increased the lipopeptide production of strain HM618 in medium containing KW. This work provides new strategies to improve lipopeptide production by B. amyloliquefaciens.

First report on hydroxylated and methoxylated polybrominated diphenyl ethers in terrestrial environment from the Arctic and Antarctica.

Terrestrial plants, which account for the world's largest biomass and constitute the basis of most food webs, take up, transform, and accumulate organic chemical contaminants from the ambient environment. In this study, we determined the concentrations and congener profiles of polybrominated diphenyl ethers (PBDEs) and hydroxylated and methoxylated polybrominated diphenyl ethers (OH-PBDEs and MeO-PBDEs) in surface soil and vegetation samples collected from the Arctic (Svalbard) and Antarctica (King George Island) during the Chinese Scientific Research Expeditions. The concentrations of total PBDEs (∑PBDEs) in soil and vegetation samples collected from the Arctic (5.6-270 pg/g dry weight) were higher than those from Antarctica (2.3-33 pg/g dw), whereas the concentrations of ∑MeO-PBDEs and ∑OH-PBDEs were lower in Arctic terrestrial samples (n.d.-0.75 and 0.0008-1.1 ng/g dw, respectively) than in samples from Antarctica (0.007-4.0 and 0.034-25 ng/g dw, respectively). Long-range atmospheric transport and human activities were potential sources of PBDEs in polar regions, whereas the dominance of ortho-substituted MeO-PBDE and OH-PBDE congeners in terrestrial matrices indicated the importance of natural sources. To the best of our knowledge, this study represents the first report on the levels and behaviors of MeO-PBDEs and OH-PBDEs in terrestrial environment of polar regions.

Distribution characteristics and source analysis of sulfate in the main rivers of Heze city, China.

Throughout the last few decades, sulfate concentrations in streamwater have received considerable attention due to their dominant role in anthropogenic acidification of surface waters. In order to determine the cycle of riverine sulfate, affected by natural weathering and anthropogenic activities, the Zhuzhaoxin River Basin and Dongyu River Basin in Heze City, China are selected. The conventional hydrochemical characteristics, distribution characteristics of sulfate concentration, and distribution characteristics of sulfur and oxygen isotopes are analyzed and texted. The results are as follows: the concentration of SO42- in the surface water of the study area increased gradually from upstream to downstream. In the study area, the δ34SSO4 and δ18OSO4 value in the surface water of Zhuzhaoxin River Basin ranges from +8.0‰ to +22.3‰ and +7.3‰ to +10.5‰, respectively, while the values of Dongyu River Basin are between +9.3‰ ∼ +9.5‰ and +4.2‰ ∼ +8.1‰. The main sources of SO42- in the Zhuzhaoxin River Basin are domestic sewage, industrial and mining wastewater and the evaporation of dissolved salt rock, and their average contribution rates are more than 50% and 30%, respectively; the main sources of SO42- in the Dongyu River Basin are agricultural activities and atmospheric precipitation, and their average contribution rates are more than 60% and 20%, respectively.

Identification and comparative expression analysis of odorant-binding proteins in the reproductive system and antennae of Athetis dissimilis.

Odorant-binding proteins (OBPs) are prevalent in the antennal transcriptomes of different orders of insects. Studies on OBPs have focused on their role in the insect chemosensory system, but knowledge of their functions in the insect testis is limited. We sequenced the transcriptomes of the Athetis dissimilis reproductive organs and analyzed the expression of AdisOBP genes in different tissues. We identified 23 OBPs in the testis and ovaries and 31 OBPs in antennal transcriptomes. The results of real-time quantitative PCR revealed that 23 of the 54 OBP genes were highly expressed in both female and male antennae, including three that exhibited male-biased expression and 15 that exhibited female-biased expression. A total of 24 OBPs were highly expressed in the testis of A. dissimilis, while expression of OBPs in the ovaries was very low. These findings highlight the functional diversity of OBPs in insects and can facilitate further studies on the OBPs in A. dissimilis and lepidopteran species.

Ecotoxicology of persistent organic pollutants in birds.

Considering the explosive growth of the list of persistent organic pollutants (POPs), the scientific community is combatting increasing challenges to protect humans and wildlife from the potentially negative consequences of POPs. Herein, we characterize the main aspects and progress in the ecotoxicology of POPs in avian species since 2000. The majority of previous efforts has revealed the global occurrence of high levels of various POPs in birds. Laboratory research and epidemiological studies imply that POPs exert a broad-spectrum of side-effects on birds by interfering with their endocrine, immune and neural system, reproduction, and development, and growth. However, inconsistent results suggest that the potential effects of POP exposure on the physiological parameters in birds are multifactorial, involving a multitude of biological processes, species-specific differences, gender, age and types of compounds. Great progress has been achieved in identifying the species-specific sensitivity to dioxin-like compounds, which is attributed to different amino acid residues in the ligand-binding domain of the aryl hydrocarbon receptor. Besides the conventional concentration additivity, several studies have suggested that different classes of POPs possibly act synergistically or antagonistically based on their concentration. However, ecotoxicology information is still recorded in a scattered and inadequate manner, including lack of enough avian species, limited number of POPs investigated, and insufficient geographical representation, and thus our understanding of the effects of POPs on birds remains rudimentary, although mechanistic understanding of their mode of action is progressing. Particularly, research on what happens to wild bird populations and their ecosystems under POP stress is still unavailable. Thus, our aim is to predict and trace the effects POPs at different biological organization levels, especially from the molecular, cellular and individual levels to the population, community and ecosystem levels because of the limited and scattered information, as mentioned above.

Bioaccumulation and Trophic Transfer of Polybrominated Diphenyl Ethers and Their Hydroxylated and Methoxylated Analogues in Polar Marine Food Webs.

Arctic and Antarctic marine ecosystems, which are important components of global biodiversity, have been severely threatened by environmental pollutants in recent decades. In this study, polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated analogues (OH-PBDEs and MeO-PBDEs) were analyzed in seawater, sediment, and marine organisms (algae, invertebrates, and fishes) collected surrounding the Arctic Yellow River Station (n = 83) and the Antarctic Great Wall Station (n = 72). PBDEs and the analogues were detectable in all polar marine matrices, except MeO-PBDEs in seawater. The concentrations of ∑PBDEs, ∑MeO-PBDEs, and ∑OH-PBDEs in the marine organisms were in the range of 0.33-16 ng/g lipid weight (lw), n.d.-2.6 ng/g lw, and 0.12-2.3 ng/g lw in the Arctic and 0.06-31 ng/g lw, n.d.-5.8 ng/g lw, and 0.17-35 ng/g lw in Antarctica, respectively. Biota-sediment bioaccumulation factor (BSAF, g TOC/g lipid) values of MeO-PBDEs (0.002-0.14) and OH-PBDEs (0.004-0.18) were lower than the BSAF values of PBDEs (0.85-12). Trophic magnification was found for ∑MeO-PBDEs, whereas trophic dilution was observed for ∑OH-PBDEs in both regions. This is one of very few investigations on trophic transfer of PBDE metabolites in the Antarctic and Arctic regions and will further strengthen concerns about the ecological risk of PBDE metabolites in remote areas.

Control of the polymyxin analog ratio by domain swapping in the nonribosomal peptide synthetase of Paenibacillus polymyxa.

Polymyxins are used as the last-line therapy against multidrug-resistant bacteria. However, their further clinical development needs to solve problems related to the presence of heterogeneous analogs, but there is still no platform or methods that can regulate the biosynthesis of polymyxin analogs. In this study, we present an approach to swap domains in the polymyxin gene cluster to regulate the production of different analogs. Following adenylation domain swapping, the proportion of polymyxin B1 increased from 41.36 to 52.90%, while that of B1-1 decreased from 18.25 to 3.09%. The ratio of polymyxin B1 and B3 following starter condensation domain swapping changed from 41.36 and 16.99 to 55.03 and 6.39%, respectively. The two domain-swapping strains produced 62.96% of polymyxin B1, 6.70% of B3 and 3.32% of B1-1. This study also revealed the presence of overflow fluxes between acetoin, 2,3-butanediol and polymyxin. To our best knowledge, this is the first report of engineering the polymyxin synthetase gene cluster in situ to regulate the relative proportions of polymyxin analogs. This research paves a way for regulating lipopeptide analogs and will facilitate the development of novel lipopeptide derivatives.

Effects of migration and reproduction on the variation in persistent organic pollutant levels in Kentish Plovers from Cangzhou Wetland, China.

Migratory Birds have been considered biovectors of persistent organic pollutants (POPs) from sources to remote areas. In the present study, Kentish Plovers (Charadrius alexandrines) were collected in different periods, including immigration, breeding and emigration, to investigate the effects of migration and reproduction on POP variations in this bird species. Significant differences were found for dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB) concentrations in muscles between the immigration and emigration periods (p < 0.01 and p < 0.001, respectively), which could be attributed to the higher pesticide residues in the wintering grounds of plovers. Female plovers could excrete about 20.8-42.7% of POP load into eggs. Nevertheless, the POP levels didn't exhibit great reduction during the breeding period compared with other seasons, which suggested that the breeding status had little impact on POP levels in female plovers. The estimated mean transport masses of POPs driven by plover migration were at the milligram level (range: 0.02-7.05 mg), suggesting that the migration of plovers had limited impacts on the redistributions of POPs along their migratory routes.

Multivariate Optimization of Tenax TA-Thermal Extraction for Determining Gaseous Phase Organophosphate Esters in Air Samples.

Suitable conditions for thermal extraction of semi-volatile organic compounds have largely been arrived at by univariate optimization or based on the recommendations provided by the manufacturers of the extraction equipment. Herein, we demonstrated the multivariate optimization of Tenax TA-thermal extraction for determining organophosphate esters in the gas phase fraction of air samples. Screening and refining experiments were performed using the eighth fraction factorial and Box-Behnken designs, respectively, and satisfactory models were obtained. Subsequently, the process was optimized by Derringer's desirability function and the global desirability was 0.7299. Following optimization, the analytes were desorbed at 290 °C for 10 minutes at a helium flow of 95 mL min-1, with the transfer line set at 290 °C. The analytes were then cryofocused at 20 °C and then cryodesorbed into the chromatographic column at 295 °C for 6 minutes. Method validation exhibited high linearity coefficients (>0.99), good precision (CV < 14%) and low detection limits (0.1-0.5 ng m-3). The method was tested by pumping 0.024 m3 of real indoor environment air through Tenax TA sorbent tubes. Furthermore, with multivariate optimization, analysis time and other resources were significantly reduced, and information about experimental factor interaction effects was investigated, as compared to the univariate optimization and other traditional methods.

Temporal variations of PM2.5-bound organophosphate flame retardants in different microenvironments in Beijing, China, and implications for human exposure.

In the present study, the temporal distribution of PM2.5-bound organophosphate flame retardants (OPFRs) was comprehensively investigated in various indoor environments as well as outdoor air in Beijing, China over a one-year period. The mean concentrations of Σ9OPFRs were 22.7 ng m-3 and 1.40 ng m-3 in paired indoor and outdoor PM2.5, respectively. The concentrations of tri-n-butyl phosphate (TNBP), tris (2-chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCIPP) in indoor PM2.5 were significantly correlated with those in outdoor PM2.5. For different indoor microenvironments, mean concentrations of Σ9OPFRs were in the order of office (29.0 ±â€¯11.7 ng m-3) > home (24.0 ±â€¯9.4 ng m-3) > dormitory (19.4 ±â€¯4.9 ng m-3) > activity room (14.4 ±â€¯3.1 ng m-3). TCIPP was the most abundant compound in the indoor PM2.5, followed by TCEP. Significantly higher concentrations of OPFRs were observed in indoor environments with more furnishing, electronics or other materials (p < 0.05). Moreover, lower levels of OPFRs in indoor air were observed at well-ventilated (with higher air exchange rate) indoor sampling sites. Concentrations of Σ9OPFRs in the activity room, dormitory, homes and outdoor sites generally increased in summer and heating seasons (November 2016 to February 2017). Significant correlations (p < 0.05) were observed between temperatures and mass concentrations of OPFRs with higher vapor pressures, i.e. TNBP, TCEP and TCIPP in all indoor and outdoor samples. Seasonal differences in human exposure were observed and the highest daily exposure dose occurred in summer. Toddlers may suffer the highest exposure risk of PM2.5-bound OPFRs via inhalation among all age groups. This is one of the very few studies that have revealed the seasonal variation and human exposure of PM2.5-bound OPFRs in different microenvironments, which shed light on emission sources and fate of OPFRs and potential human exposure pathway.

Spatial and temporal distribution of organophosphate esters in the atmosphere of the Beijing-Tianjin-Hebei region, China.

High volume air samples were collected from April 2016 to March 2017 at five locations across the Beijing-Tianjin-Hebei (BTH) region, to investigate the atmospheric occurrence of organophosphate esters (OPEs). The mean atmospheric concentrations of ∑8OPEs (gas and particle phases) varied from 531 ±â€¯393 pg/m3 to 2180 ±â€¯1490 pg/m3 with the highest level observed at the urban sampling site in Tianjin City. ∑8OPEs were predominated by the chlorinated OPEs (TCEP, TCPP, and TDCIPP), which accounted for 60% ±â€¯16% of the OPE concentrations across the BTH region. Generally, higher levels of gaseous OPEs were found in summer, while higher levels of particle-bound OPEs were observed in winter. The concentrations of gaseous OPEs were positively and significantly correlated with local temperatures (p < 0.05) and relative humidity (p < 0.01), while significantly positive correlations were found between concentrations of particle-bound OPEs and total suspended particulates (TSP) (p < 0.01). These findings confirmed that temperatures, relative humidity and levels of TSP are the main drivers for OPE distributions in different seasons and areas. Gas/particle partitioning of OPEs was also investigated based on the absorption-partitioning model (octanol-air partitioning coefficient (Koa) -based model) and Junge-Pankow adsorption-partitioning model (J-P model). Koa-based model generally showed a better performance in comparison with the measured results. The assessment of inhalation exposure risks indicated that relatively higher exposure risks were found in the urban areas, in particular, in Tianjin City (a median value of the estimated daily intake (EDI) of 106 pg/kg body weight/day), suggesting that more attention should be drawn to OPE distributions in the heavily industrialized megacities.

Altitudinal dependence of PCBs and PBDEs in soil along the two sides of Mt. Sygera, southeastern Tibetan Plateau.

Surface soil samples were collected from Mt. Sygera in the southeast of Tibetan Plateau to investigate the altitudinal distribution of PCBs and PBDEs along the two sides of the mountain. The average concentrations of PCBs and PBDEs were 177 pg g-1 dw and 15 pg g-1 dw, respectively. The relationships between the log-transformed TOC-normalized concentrations and the altitudes showed different trends on the two sides. On the windward side, there was a positive correlation for the heavier PCBs; while on the leeward side, the concentrations increased and then decreased for PCBs and PBDEs at the altitude of 4100-4200 m, corresponding to the change in vegetation. The observed discrepancy on the two sides of the mountain demonstrated different key factors associated with precipitation and the forest canopy. Additionally, values of windward-leeward Enrichment Factors (W/L EFs) for the heavier PCB congeners (PCB-138, 153, and -180) were an order of magnitude higher in sites above 4200 m, which also suggested that vegetation played an important role in the altitudinal accumulation of POPs in soil. This is one of the very few studies that have revealed the differences in altitudinal accumulation of POPs along the two sides of a mountain.

Identification and tissue distribution of chemosensory protein and odorant binding protein genes in Tropidothorax elegans Distant (Hemiptera: Lygaeidae).

Tropidothorax elegans Distant (Hemiptera: Lygaeidae) is an insect pest that inflicts damage to vegetables and flowering plants across China. The olfactory system regulates insect behavior, such as feeding, mating, oviposition and predator avoidance. Odorant-binding proteins (OBPs) and the chemosensory proteins (CSPs) are two groups of small soluble proteins that initiate olfactory signal transduction in insects. In this study, we generated antennal transcriptomes of male and female T. elegans, and identified 19 putative OBP (14 classic OBPs and five plus-C OBPs) and seven CSP genes. Through real-time quantitative PCR analysis, we found that 14 of the 19 OBP genes were highly expressed in the antennae of both adult females and males, and 3 OBP genes were expressed higher in the antennae of males than females. Some OBP genes were also highly expressed in the legs or wings. Three CSP genes were highly expressed in the antennae of both sexes, and TeleCSP7 showed higher expression in male antennae compare to females. Interestingly, one CSP gene, TeleCSP2, was expressed in all olfactory tissues. Our results provide molecular insights into further investigating of the olfactory system of an important plant pest, T. elegans.

Distribution, seasonal variation and inhalation risks of polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls and polybrominated diphenyl ethers in the atmosphere of Beijing, China.

Spatial distribution, seasonal variation and potential inhalation risks of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were investigated in the atmosphere of Beijing, using passive air samplers equipped with polyurethane foam disks. Concentrations of ΣPCDD/Fs, ΣPCBs and ΣPBDEs ranged from 8.4 to 179 fg WHO2005-TEQ/m3, 38.6-139 and 1.5-176 pg/m3, respectively. PCDFs showed higher air concentrations than those of PCDDs, indicating the influence of industrial activities and other combustion processes. The non-Aroclor congener, PCB-11, was detected in air (12.3-99.4 pg/m3) and dominated the PCB congener profiles (61.7-71.5% to ∑PCBs). The congener patterns of PBDEs showed signatures from both penta-BDE and octa-BDE products. Levels of PCDD/Fs, PCBs and PBDEs at the industrial and residential sites were higher than those at rural site, indicating human activities in urban area as potential sources. Higher air concentrations of PCDD/Fs, PCBs and PBDEs were observed in summer, which could be associated with atmospheric deposition process, re-volatilization from soil surface and volatilization from use of technical products, respectively. Results of inhalation exposure and cancer risk showed that atmospheric PCDD/Fs, dioxin-like PCBs and PBDEs did not cause high risks to the local residents of Beijing. This study provides further aid in evaluating emission sources, influencing factors and potential inhalation risks of the persistent organic pollutants to human health in mega-cities of China.

Tissue distribution and maternal transfer of persistent organic pollutants in Kentish Plovers (Charadrius alexandrines) from Cangzhou Wetland, Bohai Bay, China.

Several persistent organic pollutants, including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), were comprehensively investigated in the egg, muscle and liver samples of Kentish Plover (Charadrius alexandrines) collected from Cangzhou Wetland in western Bohai Bay, China. DDTs were the most abundant contaminants (35.4-9853ngg-1 lipid weight, lw), followed by HCHs, PCBs, PBDEs and HCB. PCDD/Fs exhibited the lowest concentrations in all tissues (8.74-4763pgg-1 lw). PCBs and PCDD/Fs were dominated by penta- and hexa-homologs, and PBDEs mostly consisted of the signature congeners of BDE formulations, such as BDE-209, -47, -153 and -99. Significant correlations were found between the lipid-normalized concentrations in muscle and liver (r: 0.37-0.90, p<0.05) and no significant differences (p<0.05), indicating the homogenous distribution of POPs in tissue lipids at steady state. The ratios of concentrations in muscle and liver (M/L) ranged from 0.20 to 1.51, and higher ratios of M/L were found for those compounds with log Kow in the range of 6.5-7.0, suggesting the preferential accumulation of mid-halogenated compounds in muscle. Significant correlations were generally observed between the concentrations in egg and the maternal tissue (p<0.05). The concentration ratios of egg to liver (E/L) were in the range of 0.10-1.24 except for p,p'-DDT (12.7), and compounds with log Kow of 6.5-7.0 exhibited higher E/L ratios, suggesting the selective maternal transfer of mid-halogenated compounds.

Cryptic Species Identification and Composition of Bemisia tabaci (Hemiptera: Aleyrodidae) Complex in Henan Province, China.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex, causing significant crop losses in China during the last decade. Although knowledge of cryptic species composition and dynamics within B. tabaci complex is critical for developing sustainable pest management strategies, limited information is available on this pest in the Henan province of China. A systematic survey of the cryptic species composition and distribution of B. tabaci complex in different locations of Henan province was conducted in 2012. The results of RAPD-PCR and the gene for the mitochondrial cytochrome oxidase subunit-1 (mtCOI) based phylogenetic relationships established using Bayesian method indicated there were four known cryptic species MEAM1, MED, Asia II 3, Asia II 9 and a new cryptic species named China 6 in Henan province. In the survey, the invasive cryptic species MED and MEAM1 were found to be predominant with wide spread distribution across the surveyed regions. On the contrary, the indigenous B. tabaci cryptic species including Asia II 3, Asia II 9 and China 6 remained with low prevalence in some surveyed regions. Cryptic species MEAM1 and MED have not completely displaced the native B. tabaci in Henan province. This current study for the first time unifies our knowledge of the diversity and distribution of B. tabaci across Henan province of China.