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Resultados 531-540 de 1,301
Isolation, characterization of Rhodococcus sp. P14 capable of degrading high-molecular-weight polycyclic aromatic hydrocarbons and aliphatic hydrocarbons
2011
Song, Xiaohui | Xu, Yan | Li, Gangmin | Zhang, Ying | Huang, Tongwang | Hu, Zhong
Rhodococcus sp. P14 was isolated from crude oil-contaminated sediments. This strain was capable of utilizing three to five rings polycyclic aromatic hydrocarbons (PAHs) including phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP) as a sole carbon and energy source. After cultivated with 50mg/L of each PAH, strain P14 removed 43% Phe, 34% Pyr and 30% BaP in 30 d. Four different hydroxyphenanthrene products derived from Phe by strain P14 (1,2,3,4-hydroxyphenanthrene) were detected using SPME–GC–MS. Strain P14 also was capable of degrading mineral oil with n-alkanes of C17 to C21 carbon chain length. Compared with glucose-grown cells, PAHs-grown cells had decreased contents of shorter-chain length fatty acids (⩽C16:0), increased contents of C18:0, Me-C19:0 and disappeared odd-number carbon chain fatty acids. The contents of unsaturated C19:1, Me-C19:0 increased and C18:0 decreased in mineral oil-grown cells. At the same time, the strain P14 tended to float when cultivated in mineral oil-supplemented liquid medium. The degradation capability of P14 to alkane and PAHs and its floating characteristics will be very helpful for future’s application in oil-spill bioremediation.
Mostrar más [+] Menos [-]Richards Bay Harbour: Metal exposure monitoring over the last 34years
2011
Greenfield, R. | Wepener, V. | Degger, N. | Brink, K.
Richards Bay Harbour is South Africa’s premier bulk cargo port. It was constructed in the Mhlathuze estuary in 1976 and over the past 34years has become South Africa’s most modern and largest cargo handling port. Although no official monitoring programme is in progress various studies by different groups have provided relevant data with respect to changing metal levels in brown mussel tissue (Perna perna) over the last 34years. Eleven elements were analysed in brown mussels from the main channel in Richards Bay Harbour using ICP-MS. The results indicate that the metal concentrations in the mussel tissue remained relatively constant between 1974 and 2005. The mean metal concentrations increased significantly in 2005 possibly due to the construction of the new coal terminal and associated dredging activities. Mean metal concentrations in the 2008 sampling event were also elevated due to increased run off during an above average rainy season.
Mostrar más [+] Menos [-]Immune responses to combined effect of hypoxia and high temperature in the green-lipped mussel Perna viridis
2011
Wang, Youji | Hu, Menghong | Shin, Paul K.S. | Cheung, Siu Gin
Flow cytometry was used to examine immune responses in haemocytes of the green-lipped mussel Perna viridis under six combinations of oxygen level (1.5mg O₂l⁻¹, 6.0mg O₂l⁻¹) and temperature (20°C, 25°C and 30°C) at 24h, 48h, 96h and 168h. The mussels were then transferred to normoxic condition (6.0mg O₂l⁻¹) at 20°C for further 24h to study their recovery from the combined hypoxic and temperature stress. Esterase (Est), reactive oxygen species (ROS), lysosome content (Lyso) and phagocytosis (Pha) were reduced at high temperatures, whereas hypoxia resulted in higher haemocyte mortality (HM) and reduced phagocytosis. For HM and Pha, changes were observed after being exposed to the stresses for 96h, whereas only a 24h period was required for ROS and Lyso, and a 48h one for Est. Recovery from the stresses was observed for HM and Pha but not other immune responses.
Mostrar más [+] Menos [-]Expression of superoxide dismutase (SOD) genes from the copper-exposed polychaete, Neanthes succinea
2011
Rhee, Jae-Sung | Won, Eun-Ji | Kim, Ryeo-Ok | Lee, Jehee | Shin, Kyung-Hoon | Lee, Jae-seong
To evaluate the superoxide dismutase (SOD) genes as a potential indicator of environmental stress, we cloned and sequenced the full-length cDNA of a Cu/Zn-SOD and Mn-SOD genes from the marine polychaete, Neanthes succinea. Ns-Cu/Zn- and Mn-SOD expression was measured using quantitative real-time RT-PCR in response to the oxidative stress induced by copper in the form of CuCl₂. Ns-Cu/Zn-SOD expression increased in a dose dependent manner but the increase of Mn-SOD expression was evident only at a high concentration of copper. Particularly, Ns-Mn-SOD dramatically increased in the 72μg/L CuCl₂-exposed groups, indicating that both Ns-SOD genes were induced by copper exposure. These results suggest that Ns-Cu/Zn- and Ns-Mn-SOD would play important roles in the detoxification of cellular oxidative stresses in the polychaete, N. succinea. Furthermore, as part of field work, the marine polychaete, N. succineaCu/Zn-SOD mRNA collected from the polluted area was accordingly upregulated in expression but not for NS-Mn-SOD.
Mostrar más [+] Menos [-]In vitro profiling of endocrine disrupting potency of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) and related hydroxylated analogs (HO-PBDEs)
2011
Liu, Hongling | Hu, Wei | Sun, Hong | Shen, Ouxi | Wang, Xinru | Lam, Michael H.W. | Giesy, John P. | Zhang, Xiaowei | Yu, Hongxia
The potential of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) and its related hydroxylated analogs (2′-HO-BDE28, 6-HO-BDE47, 4′-HO-BDE17, and 4′-HO-BDE49) to modulate estrogen/thyroid/androgen receptor-(ER, TR, AR), mediated responses were investigated by use of reporter gene assays. Exposure to 1 or 10μM, 4′-HO-BDE17 significantly up-regulated expression of Luc, whereas other four chemicals did not induce Luc expression under control of the ER. Anti-estrogenic potency was observed for 4′-HO-BDE17 (IC50=1.14μM)>6-HO-BDE47 (IC50=2.65μM)>2′-HO-BDE28 (IC50=9.49μM)>BDE47 (IC50=21.11μM). No anti-estrogenic effect of 4′-HO-BDE49 was observed. Both 4′-HO-BDE17, 4′-HO-BDE49 resulted in greater responses of Luc expression induced by T3. BDE47, 2′-HO-BDE28, 6-HO-BDE47 did not show any effect on the expression of Luc induced by 5nM T3. 6-HO-BDE47 (IC50=0.34μM)>4′-HO-BDE17 (IC50=1.41μM)>BDE47 (IC50=3.83μM)>2′-HO-BDE28 (IC50=29.22μM) exhibited anti-androgenic potency, while 4′-HO-BDE49 did not show androgenic transcriptional activity.
Mostrar más [+] Menos [-]Differential concentration of Technetium-99 (⁹⁹Tc) in common intertidal molluscs with different food habits
2011
Sjøtun, K. | Heldal, H.E. | Brakstad, D.S.
Concentration of ⁹⁹Tc has been measured in fucoids and molluscs, sampled in a sheltered intertidal at the southwest coast of Norway from February to November 2006. The concentrations of ⁹⁹Tc in molluscs differed significantly between species. The filtering bivalve Mytilus edulis had the lowest concentrations with averages of 2.3–5.9Bqkg⁻¹d.w., while the herbivorous gastropods Littorinalittorina, Littorina obtusata and Patella vulgata had higher concentrations. P. vulgata and L. obtusata had the highest concentrations, 40–47 and 26–30Bqkg⁻¹d.w., respectively. L. obtusata has a specialized habit of living, and prefers to feed on fucoids. P. vulgata can graze extensively on the fucoid Ascophyllum nodosum when available. Fucoids are known to have very high uptake of ⁹⁹Tc, and this was also found in the present study. The high ⁹⁹Tc-concentrations of L. obtusata and P. vulgata are most likely due to their habit of feeding on fucoids.
Mostrar más [+] Menos [-]Bacterioplankton dynamics along the gradient from highly eutrophic Pearl River Estuary to oligotrophic northern South China Sea in wet season: Implication for anthropogenic inputs
2011
Zhou, Weihua | Long, Aimin | Jiang, Tao | Chen, Shaoyong | Huang, Liangmin | Huang, Hui | Cai, Chuanghua | Yan, Yan
Bacterioplankton abundance (BA) and biomass (BB) from the eutrophic Pearl River Estuary (PRE) to the oligotrophic northern South China Sea (NSCS) were studied in the wet season. BA was significantly higher (p<0.05) in PRE (12.51±3.52×10⁸cellsL⁻¹), than in the continental shelf neritic province (CSNP, 4.95±2.21×10⁸cellsL⁻¹) and in the deep oceanic province (OP, 3.16±1.56×10⁸cellsL⁻¹). Nutrient-replete PRE waters (DIN>100μM and PO₄>1μM) resulted in high chl a and BB, whereas nutrient-depleted offshore waters (DIN <5μM and PO₄<0.5μM) had low biomass. Temperature (>26°C) was not the controlling factor of BA. BB was significantly correlated with chl a biomass both in PRE and NSCS. The bacteria to phytoplankton biomass (BB/PB) ratio increased clearly along the gradient from near-shore PRE (0.15) to offshore CSNP (0.93) and deep OP (2.75), indicating the important role of small cells in the open ocean compared to estuarine and coastal zones.
Mostrar más [+] Menos [-]Organochlorine pesticides (OCPs) in soils and sediments, southeast China: A case study in Xinghua Bay
2011
Zhang, Jiaquan | Qi, Shihua | Xing, Xinli | Tan, Lingzhi | Gong, Xiangyi | Zhang, Yuan | Zhang, Junpeng
This study evaluated the contamination status and distribution of organochlorine pesticides (OCPs) between Xinghua Bay and adjacent watersheds in Putian region, southeast China. Twenty-five surface soil samples and two sediment cores were collected from two watersheds and the Xinghua Bay, respectively. Results showed that the concentrations of OCPs in samples of the Mulan River Watershed (MRW), the Qiulu River Watershed (QRW), the inner bay core (IBC) and the open bay core (OBC) were in the range of 4.96–38.20ng/g, 4.62–22.80ng/g, 1.84–80.46ng/g and 1.87–23.43ng/g, respectively. The mean concentration of OCPs was in an order: IBC>MRW>QRW>OBC. The higher concentration of OCPs in recent periods may suggest that a certain amount of OCPs were still input to this area.
Mostrar más [+] Menos [-]Dioxin-like compounds in sediments from the Daliao River Estuary of Bohai Sea: Distribution and their influencing factors
2011
Zhao, Xiaofeng. | Zhang, Haijun | Fan, Jingfeng | Guan, Daoming | Zhao, Huade | Ni, Yuwen | Li, Yun | Chen, Jiping
The concentrations, compositional profiles, and potential ecological risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in sediments of the Daliao River Estuary were investigated. Total concentrations of PCDD/Fs, PCBs, and PCNs were in the range of 11.3–133.2ng/kg dry weight (dw), 1 971–37 632ng/kg dw and 33.1–284.4ng/kg dw, respectively. The total TEQ values varied from 0.37 to 4.08ng/kg dw, with the dominant contributions by PCDD/Fs, then by PCBs and PCNs. The spatial distributions of PCDD/Fs, PCBs and PCNs in the river estuary were much related to hydrodynamic conditions. The risk of contamination to the deeper sea was increased in the flood seasons. Moreover, our data confirmed that both organic matter in sediments and molecular properties of dioxin-like compounds were the factors which strongly influenced the partition behavior of these dioxin-like compounds between sediments and water phase in the estuarine zone.
Mostrar más [+] Menos [-]Status of macrobenthic community of Manifa–Tanajib Bay System of Saudi Arabia based on a once-off sampling event
2011
Joydas, T.V. | Krishnakumar, P.K. | Qurban, Mohammad A. | Ali, Said M. | Al-Suwailem, Abdulaziz | Al-Abdulkader, Khaled
Shallow water bays located in the western Arabian Gulf experience harsh environmental conditions. Some of these bays, including Manifa–Tanajib Bay System (MTBS), were also exposed to the 1991 oil pollution event. This study investigates the status of the macrobenthos in MTBS during 2006. This bay system is characterized by very shallow inner bays with elevated salinity and temperature compared to the rest of the bay area. As a result mainly of the hyper salinity, the inner bay communities are distinct from the outer bay communities. Overall, fairly high species richness with several rare species was observed. High Shannon–Wiener diversity values and ABC plots indicated the healthy status of the polychaete communities, while BOPA index indicated slightly polluted status in 20% of the stations. The oil sensitive amphipods were not completely re-colonized in 20% of the stations, even after 15years of recovery from the 1991 oil spill.
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