Complex population genetic and demographic history of the Salangid, Neosalanx taihuensis, based on cytochrome b sequences

<p>Abstract</p> <p>Background</p> <p>The Salangid icefish <it>Neosalanx taihuensis </it>(Salangidae) is an economically important fish, which is endemic to China, restricted to large freshwater systems (e.g. lakes, large rivers and estuaries) and typically exhibit low vagility. The continuous distribution ranges from the temperate region of the Huai and Yellow River basins to the subtropical region of the Pearl River basin. This wide ranging distribution makes the species an ideal model for the study of palaeoclimatic effects on population genetic structure and phylogeography. Here, we aim to analyze population genetic differentiation within and between river basins and demographic history in order to understand how this species responded to severe climatic oscillations, decline of the sea levels during the Pleistocene ice ages and tectonic activity.</p> <p>Results</p> <p>We obtained the complete mtDNA cytochrome <it>b </it>sequences (1141 bp) of 354 individuals from 13 populations in the Pearl River, the Yangze River and the Huai River basin. Thirty-six haplotypes were detected. Haplotype frequency distributions were strongly skewed, with most haplotypes (n = 24) represented only in single samples each and thus restricted to a single population. The most common haplotype (H36) was found in 49.15% of all individuals. Analysis of molecular variance (AMOVA) revealed a random pattern in the distribution of genetic diversity, which is inconsistent with contemporary hydrological structure. Significant levels of genetic subdivision were detected among populations within basins rather than between the three basins. Demographic analysis revealed that the population size in the Pearl River basin has remained relatively constant whereas the populations in the Yangze River and the Huai River basins expanded about 221 and 190 kyr ago, respectively, with the majority of mutations occurring after the last glacial maximum (LGM).</p> <p>Conclusion</p> <p>The observed complex genetic pattern of <it>N. taihuensis </it>is coherent with a scenario of multiple unrelated founding events by long-distance colonization and dispersal combined with contiguous population expansion and locally restricted gene flow. We also found that this species was likely severely impacted by past glaciations. More favourable climate and the formation of large suitable habitations together facilitated population expansion after the late Quaternary (especially the LGM). We proposed that all populations should be managed and conserved separately, especially for habitat protection.</p

Electromagnetic Transmit Array with Optical Control for Beamforming

This Proof-Of-Concept Paper Demonstrates the Feasibility of using a Slide Projector to Steer the Beam of a Transmit Array by Adding Solar Cells and Varactor Diodes to Each Unit Cell. by Irradiating Each Solar Cell with the Light of Different Intensities from a Slide Projector, the Measured Phase of the Wave Transmitted by the 4x4 Transmit Array Shifts within 92° at 4.26 GHz, While the Variation in Magnitude is Measured within 4 DB. Different Light Configurations Are Identified Via a Searching Algorithm to Achieve Peak/null Beamforming in a Particular Direction. the Beam of the Prototypical 4x4 Transmit Array Can Be Shifted by ±24° in Terms of the Peaks and -30° to 36° in Terms of the Nulls. the Concept of Adding Light Modulation to the Transmit Array with a Slide Projector Can Provide Update Rates of 10s of Milliseconds with Control of Brightness and Color Distributed over a Large Area of the Array

PCDD/F; PAH and heavy metals in the sewage sludge from six wastewater treatment plants in Beijing;China

In order to better understand land application of sewage sludge, the characterization of heavy metals, PCDD/F and PAHs in sewage sludge was investigated from six different wastewater treatment plants (WWTP) in Beijing City, China. It was found that the total concentrations of Zn in Wujiacun (WJC) sewage sludge, and Cd and Hg in sewage sludge generated from all of the six different places are higher than Chinese regulation limit of pollutants for sludge to be used for agriculture (GB 18918-2002). The levels of 16 PAHs that have been categorized as priority pollutants by US EPA in the sewage sludge samples varied from 2467 to 25923 mu g/kg (dry weight), the highest values of 25923 pg/kg being found in WJC WWTP. The concentrations of Benzo[a]pyrene were as high as 6.1 mg/kg dry weight in WJC sewage sludge, exceeding the maximum permitted content by GB 18918-2002. Individual PAH content varies considerably with sewage samples. The ratios of anthracene to anthracene plus phenanthrene (An/178), benz[a]anthracene to benz[a]anthracene plus chrysene (BaA/228), indene[1,2,3-cd]pyrene to indene[1,2,3-cd] pyrene plus benzo[g,h,i]perylene (In/In + BP), and fluoranthene to fluoranthene plus pyrene (Fl/Fl + Py) suggest that petroleum and combustion of fossil fuel were the dominant contributions for the PAHs in sewage sludge. The concentrations of total PCDD/F in the sewage sludge ranged from 330 to 4245 pg/g d.w. The toxicity equivalent concentrations is between 3.47-88.24 pg I-TEQ according to NATO/CCMS, which is below Chinese legislation limit value proposed for land application. The PCDD/F congener/homologue profiles found in the Beijing samples indicated that the high chlorinated PCDD/F contamination might originate mainly from PCP-related source and depositional sources while the low chlorinated PCDD/F homologues could be originating from incineration or coal combustion. The major source of PCDD/Fs in Beijing sludge is still unclear. (c) 2006 Elsevier Ltd. All rights reserved

Isolation and characterization of a Pseudomonas oleovorans degrading the chloroacetamide herbicide acetochlor. Biodegradation 2006;17:219–25

Abstract To date, no pure bacterial cultures that could degrade acetochlor have been described. In this study, one strain of microorganism capable of degrading acetochlor, designated as LCa2, was isolated from acetochlor-contaminated soil. The strain LCa2 is Pseudomonas oleovorans according to the criteria of BergeyÕs manual of determinative bacteriology and sequence analysis of the partial 16S rRNA gene. Optimum growth temperature and pH were 35°C and 8.0, respectively. The strain could degrade 98.03% of acetochlor treated at a concentration of 7.6 mg l )1 after 7 days of incubation and could tolerate 200 mg l )1 of acetochlor. When the acetochlor concentration became higher, the degradation cycle became longer. The acetochlor biodegradation products were identified by GC-MS based on mass spectral data and fragmentation patterns. The main plausible degradative pathways involved dechlorination, hydroxylation, N-dealkylation, C-dealkylation and dehydrogenation

ESTROGEN-LIKE PROPERTIES OF PERFLUOROOCTANOIC ACID AS REVEALED BY EXPRESSING HEPATIC ESTROGEN-RESPONSIVE GENES IN RARE MINNOWS (GOBIOCYPRIS RARUS)

Perfluorooctanoic acid (PFOA) is an important perfluorinated compound (PFC) with various applications and has been widely disseminated in the environment, wildlife, and humans. The present study investigated the effects of waterborne PFOA on the expression of hepatic estrogen-responsive genes, vitellogenin (VTG), and estrogen receptor P (ER beta) and on the gonadal development in a freshwater rare minnow (Gobiocypris rarus). The mRNA levels of VTG and ER beta were determined using reverse transcription polymerase chain reaction (RT-PCR) techniques, and VTG protein levels were identified using enzyme-linked immunosorbent assay. A significant increase of VTG expression in the livers of both mature males and females was observed after 14 and 28 d of exposure to 3, 10, and 30 mg/L PFOA, indicating that PFOA could induce VTG synthesis. The expression of ERP increased significantly in livers of both mature males and females after a 14-d exposure, although no difference was observed after a 28-d exposure. The development of oocytes in testes exposed to PFOA also provided evidence of estrogenic activity in males. The ovaries of PFOA-exposed females underwent degeneration, as reported in other fish species exposed to environmental estrogens. This preliminary study indicates that PFOA can disturb the activity of estrogen in mature male rare minnows by inducing hepatic estrogen-responsive genes, VTG and ER beta, and barrier female reproduction