This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Estrogens, a group of steroid hormones, are serious environmental pollutants due to their persist... more Estrogens, a group of steroid hormones, are serious environmental pollutants due to their persistence, ubiquity, and endocrine-disrupting toxicity. Natural and synthetic estrogens, such as 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), respectively, have been found in the influent of municipal wastewater treatment plants. The removal and biotransformation of mixed or single E2 and EE2 by six microalgal species, including three local isolates of Chlamydomonas sp. (WW), Chlorella sp. (2f5aia), and Chlorella sp. (1uoai) and three commercially available species, namely Scenedesmus quadricauda (= Desmodesmus communis) (SQ), Selenastrum capricornutum (SC), and Chlorella vulgaris (CV), were compared. The biological removal of estrogen was incubation time-and species-dependent. Among six species, SC had the highest removal ability for both E2 and EE2; their removal increased with incubation time and achieved 93.9 and 75.3 % removal, respectively, at the end of incubation. After 7-day incubation, the removal percentage of mixed EE2 by SC was significantly higher than that of single EE2 (P ≤ 0.05). Differences in the removal percentages of E2 and EE2 between commercial and local species were not significant, as reflected by the comparable removal efficiency among three Chlorella species, CV, 1uoai, and 2f5aia, with the highest removal of E2, either in mixed or in single treatment, at day 2. In all species, the percentages of E2 or EE2 taken up into cells were very low (0.2-9.6 %) when compared to the respective biological removal percentages. E2 was easily transformed into estrone (E1) and some unknown products by all microalgal species, while the products for EE2 transformation could not be identified due to the limited availability of the standards for metabolites.
The biosorption and biodegradation of tributyltin (TBT) by free cells of a resistant rnicroalgal ... more The biosorption and biodegradation of tributyltin (TBT) by free cells of a resistant rnicroalgal species, Chlorella sorokiniana at two different densities, 1x10~ cells ml" (low) and 1 x107 (high) were investigated. TBT in contaminated water was continuously removed by rnicroalgal cells and reached a 54% and 74% removal at the end of 14 days treatment in low and h g h density cultures, respectively. The pattern of TBT removal in both densities was similar: with the decreases of TBT in water, TBT uptake by algal cells increased, reached a peak and declined to low levels towards the end of the treatment period. In the high density culture, total amounts of TBT uptake, including the adsorption on cell surface and absorption inside the cells, increased from 109 to 159pg TBT' from days 1 to 7, then declined to 95pg TBT' at day 14. The proportions of TBT adsorbed on the cell surface decreased while that in the intracellular fraction increased with time, suggesting that the adsorbed TBT moved gradually into the cells for stepwise debutylation. The two degradation products, DBT (dibutyltin) and MBT (monbutyltin), started to appear in the intracellular fraction from day 3 and day 7onwards in high and low density cultures, respectively, with more MBT than that of DBT. These results indicate that C. sorokiniana was not only capable of removing TBT from contaminated water, TBT was absorbed and degraded into DBT which was then rapidly metabolized to MBT by intracellular enzymes.
Academic research on dinoflagellate, the primary causative agent of harmful algal blooms (HABs), ... more Academic research on dinoflagellate, the primary causative agent of harmful algal blooms (HABs), is often hindered by the coexistence with bacteria in laboratory cultures. The development of axenic dinoflagellate cultures is challenging and no universally accepted method suit for different algal species. In this study, we demonstrated a promising approach combined density gradient centrifugation, antibiotic treatment, and serial dilution to generate axenic cultures of Karenia mikimotoi (KMHK). Density gradient centrifugation and antibiotic treatments reduced the bacterial population from 5.79 ± 0.22 log10 CFU/mL to 1.13 ± 0.07 log10 CFU/mL. The treated KMHK cells were rendered axenic through serial dilution, and algal cells in different dilutions with the absence of unculturable bacteria were isolated. Axenicity was verified through bacterial (16S) and fungal internal transcribed spacer (ITS) sequencing and DAPI epifluorescence microscopy. Axenic KMHK culture regrew from 1000 to 940...
A growing concern for the high consumption of antibiotics in aquaculture has initiated a search f... more A growing concern for the high consumption of antibiotics in aquaculture has initiated a search for alternative methods of disease control. Improved resistance against infectious diseases can be achieved by the use of probiotics. Probiotics are live microorganisms supplemented in food or feed which give beneficial effects on the intestinal microbial balance. In the present study a dry feed containing lactic acid bacteria (Camobacterium diver gens) isolated from Atlantic cod (Gadus morhua) intestines was given to cod fry. After three weeks of feeding the fry was exposed to a virulent strain of Vibrio anguillarum. The death rate was recorded during further three weeks of feeding with lactic acid bacteria supplemented feed. A certain improvement of disease resistance was obtained, and at the end of the experiment lactic acid bacteria dominated the intestinal flora in surviving fish given feed supplemented with lactic acid bacteria. No obvious growth inhibition of V. anguillarum was observed in an in vitro mixed culture of this bacterium and the C. divergens isolated from cod intestines.
Aims Limited information is available on plant rhizosphere processes for removing antibiotics in ... more Aims Limited information is available on plant rhizosphere processes for removing antibiotics in antibioticcontaminated waters. This study identifies rhizosphere processes and evaluates their relative contributions for the macrolides (ML) removal in aquatic plant systems. Methods A flask-scale experiment (100 and 300 μg/L ML) incorporating Juncus effuses and Canna indica was used to identify the root adsorption, rhizobacterial influences, and plant uptake responsible for the ML (i.e., anhydroerythromycin A, roxithromycin, clarithromycin and tilmicosin) removal. Results Total ML removal rates due to rhizosphere processes were respectively 43.7-67.6% and 44.3-82.2% at 100 and 300 μg/L ML. J. effuses removed ML more effectively than C. indica (P < 0.05). The relative contribution of rhizospheric pathways to remove all ML followed the order: root sorption > rhizobacterial influence > plant uptake (P < 0.01). Sorption and rhizobacterial activity were important removal pathways in wetland plant microcosms, accounting for 36.5-72.8% and 20.5-54.2% of the total rhizosphere associated removal of ML, respectively. Conclusions Root sorption and rhizobacterial influence were the main rhizospheric pathways of ML removal in aquatic plant systems. Fe plaque on the root surface, rhizobacterial number and bacterial activity play significant roles in the removal of target pollutants.
This study examined the accumulation of As species, Se, Cu, Zn, Cd and Pb in the halophyte Juncus... more This study examined the accumulation of As species, Se, Cu, Zn, Cd and Pb in the halophyte Juncus acutus, collected from three anthropogenically impacted estuaries in NSW, Australia. As concentration ranged from 4 to 22 μg/g at Georges River, 2-16 μg/g at Lake Macquarie and 6 μg/g at Hunter Estuary. Inorganic As was accumulated mainly in roots with low translocation to culm with a greater abundance of AsV. However, AsIII (TF = 0.32) showed greater mobility from the roots to shoots than AsV (TF = 0.04), indicating a higher quantity of AsIII specific transporter assemblages in the plasmalemma of the endodermis or cytoplasmic reduction of AsV to AsIII in culms. Metal(loid)s, including As (90%), were predominantly in root tissues and very limited translocation to culm, indicating the species is a useful phytostabiliser. As and all other metal(loid)s in roots were correlated with sediment loads (p < 0.05, R2 = 0.10-0.52), indicating the species would be an accumulative bioindicator.
The toxic affect of tributyltin (TBT) on six species of two different genera of microalgae, namel... more The toxic affect of tributyltin (TBT) on six species of two different genera of microalgae, namely Chlorella sp. and Scenedesmus sp. was examined. The resistance of the commercially available species and isolates obtained from polluted water in Hong Kong and Wuhan, PRC to TBT were also compared. Chlorella vulgaris and S. dimorphus were commercial species while C. sorokiniana, S. quadricauda, C. miniata, and S. platydiscus were isolates. Among the tested species, C. vulgaris was most resistant to TBT, and the 7-d IC50 values measured in terms of cell number and chlorophyll content were 220 and 262 µg/l, respectively. The second most resistant species was C. sorokiniana (Wuhan isolate) and their IC50 value was around 100 µg/l. On the other hand, C. miniata (Hong Kong isolate) was the most sensitive species, their growth was strongly inhibited by TBT and the 7-d IC50 was 21 µg/l. For the three Scenedesmus species, S. dimorphus and S. platydiscus (both were isolates) had similar growth ...
应用GC－MG技术分析了深圳大亚湾大鹏澳及厦门岛南岸海域沿岸几个站位沉积物中可提取性磷脂酯结合态脂肪酸的含量和组成成份；同时采用丫啶橙荧光染色计数法测定了这些沉积物中细菌的丰度、生物量。结果表明... more 应用GC－MG技术分析了深圳大亚湾大鹏澳及厦门岛南岸海域沿岸几个站位沉积物中可提取性磷脂酯结合态脂肪酸的含量和组成成份；同时采用丫啶橙荧光染色计数法测定了这些沉积物中细菌的丰度、生物量。结果表明，在这些沉积物中细菌的生物量与磷脂酯结合态脂肪酸的组分的含量有着正相关关系。说明在环境生态研究中，可提取性磷脂作为海洋和河口沉积物中微生物生物量的生物标志物的可行性。国家自然科学基金（49676302号）及大亚湾海洋生物综合实验站（MBRS）基金（S9509号）资助
Laguncularia racemosa and Sonneratia apetala are fast-growing exotic mangrove species in Southern... more Laguncularia racemosa and Sonneratia apetala are fast-growing exotic mangrove species in Southern China and widely used for afforestation. However, the invasiveness of the two exotic species is still unclear. We compared structural and physiological traits and energy-use related traits between L. racemosa and S. apetala, and with two natives (Kandelia obovata and Aegiceras corniculatum) in northern Fujian. Results showed that leaf construction cost based on mass (CCM) and caloric values of L. racemosa were significantly lower than S. apetala, and the two natives had highest CCM. Because lower CCM, L. racemosa grew faster with a taller height (4.83 m) and wider ground diameter circumference (40.03 cm) than S. apetala (4.43 m tall and 35.63 cm wide) and the two natives (2.42 m tall and 26.78 cm wide). These findings indicated that L. racemosa could be more invasive than S. apetala in mangrove forests in northern Fujian, China where it still grew well, which deserves more attention.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Estrogens, a group of steroid hormones, are serious environmental pollutants due to their persist... more Estrogens, a group of steroid hormones, are serious environmental pollutants due to their persistence, ubiquity, and endocrine-disrupting toxicity. Natural and synthetic estrogens, such as 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), respectively, have been found in the influent of municipal wastewater treatment plants. The removal and biotransformation of mixed or single E2 and EE2 by six microalgal species, including three local isolates of Chlamydomonas sp. (WW), Chlorella sp. (2f5aia), and Chlorella sp. (1uoai) and three commercially available species, namely Scenedesmus quadricauda (= Desmodesmus communis) (SQ), Selenastrum capricornutum (SC), and Chlorella vulgaris (CV), were compared. The biological removal of estrogen was incubation time-and species-dependent. Among six species, SC had the highest removal ability for both E2 and EE2; their removal increased with incubation time and achieved 93.9 and 75.3 % removal, respectively, at the end of incubation. After 7-day incubation, the removal percentage of mixed EE2 by SC was significantly higher than that of single EE2 (P ≤ 0.05). Differences in the removal percentages of E2 and EE2 between commercial and local species were not significant, as reflected by the comparable removal efficiency among three Chlorella species, CV, 1uoai, and 2f5aia, with the highest removal of E2, either in mixed or in single treatment, at day 2. In all species, the percentages of E2 or EE2 taken up into cells were very low (0.2-9.6 %) when compared to the respective biological removal percentages. E2 was easily transformed into estrone (E1) and some unknown products by all microalgal species, while the products for EE2 transformation could not be identified due to the limited availability of the standards for metabolites.
The biosorption and biodegradation of tributyltin (TBT) by free cells of a resistant rnicroalgal ... more The biosorption and biodegradation of tributyltin (TBT) by free cells of a resistant rnicroalgal species, Chlorella sorokiniana at two different densities, 1x10~ cells ml" (low) and 1 x107 (high) were investigated. TBT in contaminated water was continuously removed by rnicroalgal cells and reached a 54% and 74% removal at the end of 14 days treatment in low and h g h density cultures, respectively. The pattern of TBT removal in both densities was similar: with the decreases of TBT in water, TBT uptake by algal cells increased, reached a peak and declined to low levels towards the end of the treatment period. In the high density culture, total amounts of TBT uptake, including the adsorption on cell surface and absorption inside the cells, increased from 109 to 159pg TBT' from days 1 to 7, then declined to 95pg TBT' at day 14. The proportions of TBT adsorbed on the cell surface decreased while that in the intracellular fraction increased with time, suggesting that the adsorbed TBT moved gradually into the cells for stepwise debutylation. The two degradation products, DBT (dibutyltin) and MBT (monbutyltin), started to appear in the intracellular fraction from day 3 and day 7onwards in high and low density cultures, respectively, with more MBT than that of DBT. These results indicate that C. sorokiniana was not only capable of removing TBT from contaminated water, TBT was absorbed and degraded into DBT which was then rapidly metabolized to MBT by intracellular enzymes.
Academic research on dinoflagellate, the primary causative agent of harmful algal blooms (HABs), ... more Academic research on dinoflagellate, the primary causative agent of harmful algal blooms (HABs), is often hindered by the coexistence with bacteria in laboratory cultures. The development of axenic dinoflagellate cultures is challenging and no universally accepted method suit for different algal species. In this study, we demonstrated a promising approach combined density gradient centrifugation, antibiotic treatment, and serial dilution to generate axenic cultures of Karenia mikimotoi (KMHK). Density gradient centrifugation and antibiotic treatments reduced the bacterial population from 5.79 ± 0.22 log10 CFU/mL to 1.13 ± 0.07 log10 CFU/mL. The treated KMHK cells were rendered axenic through serial dilution, and algal cells in different dilutions with the absence of unculturable bacteria were isolated. Axenicity was verified through bacterial (16S) and fungal internal transcribed spacer (ITS) sequencing and DAPI epifluorescence microscopy. Axenic KMHK culture regrew from 1000 to 940...
A growing concern for the high consumption of antibiotics in aquaculture has initiated a search f... more A growing concern for the high consumption of antibiotics in aquaculture has initiated a search for alternative methods of disease control. Improved resistance against infectious diseases can be achieved by the use of probiotics. Probiotics are live microorganisms supplemented in food or feed which give beneficial effects on the intestinal microbial balance. In the present study a dry feed containing lactic acid bacteria (Camobacterium diver gens) isolated from Atlantic cod (Gadus morhua) intestines was given to cod fry. After three weeks of feeding the fry was exposed to a virulent strain of Vibrio anguillarum. The death rate was recorded during further three weeks of feeding with lactic acid bacteria supplemented feed. A certain improvement of disease resistance was obtained, and at the end of the experiment lactic acid bacteria dominated the intestinal flora in surviving fish given feed supplemented with lactic acid bacteria. No obvious growth inhibition of V. anguillarum was observed in an in vitro mixed culture of this bacterium and the C. divergens isolated from cod intestines.
Aims Limited information is available on plant rhizosphere processes for removing antibiotics in ... more Aims Limited information is available on plant rhizosphere processes for removing antibiotics in antibioticcontaminated waters. This study identifies rhizosphere processes and evaluates their relative contributions for the macrolides (ML) removal in aquatic plant systems. Methods A flask-scale experiment (100 and 300 μg/L ML) incorporating Juncus effuses and Canna indica was used to identify the root adsorption, rhizobacterial influences, and plant uptake responsible for the ML (i.e., anhydroerythromycin A, roxithromycin, clarithromycin and tilmicosin) removal. Results Total ML removal rates due to rhizosphere processes were respectively 43.7-67.6% and 44.3-82.2% at 100 and 300 μg/L ML. J. effuses removed ML more effectively than C. indica (P < 0.05). The relative contribution of rhizospheric pathways to remove all ML followed the order: root sorption > rhizobacterial influence > plant uptake (P < 0.01). Sorption and rhizobacterial activity were important removal pathways in wetland plant microcosms, accounting for 36.5-72.8% and 20.5-54.2% of the total rhizosphere associated removal of ML, respectively. Conclusions Root sorption and rhizobacterial influence were the main rhizospheric pathways of ML removal in aquatic plant systems. Fe plaque on the root surface, rhizobacterial number and bacterial activity play significant roles in the removal of target pollutants.
This study examined the accumulation of As species, Se, Cu, Zn, Cd and Pb in the halophyte Juncus... more This study examined the accumulation of As species, Se, Cu, Zn, Cd and Pb in the halophyte Juncus acutus, collected from three anthropogenically impacted estuaries in NSW, Australia. As concentration ranged from 4 to 22 μg/g at Georges River, 2-16 μg/g at Lake Macquarie and 6 μg/g at Hunter Estuary. Inorganic As was accumulated mainly in roots with low translocation to culm with a greater abundance of AsV. However, AsIII (TF = 0.32) showed greater mobility from the roots to shoots than AsV (TF = 0.04), indicating a higher quantity of AsIII specific transporter assemblages in the plasmalemma of the endodermis or cytoplasmic reduction of AsV to AsIII in culms. Metal(loid)s, including As (90%), were predominantly in root tissues and very limited translocation to culm, indicating the species is a useful phytostabiliser. As and all other metal(loid)s in roots were correlated with sediment loads (p < 0.05, R2 = 0.10-0.52), indicating the species would be an accumulative bioindicator.
The toxic affect of tributyltin (TBT) on six species of two different genera of microalgae, namel... more The toxic affect of tributyltin (TBT) on six species of two different genera of microalgae, namely Chlorella sp. and Scenedesmus sp. was examined. The resistance of the commercially available species and isolates obtained from polluted water in Hong Kong and Wuhan, PRC to TBT were also compared. Chlorella vulgaris and S. dimorphus were commercial species while C. sorokiniana, S. quadricauda, C. miniata, and S. platydiscus were isolates. Among the tested species, C. vulgaris was most resistant to TBT, and the 7-d IC50 values measured in terms of cell number and chlorophyll content were 220 and 262 µg/l, respectively. The second most resistant species was C. sorokiniana (Wuhan isolate) and their IC50 value was around 100 µg/l. On the other hand, C. miniata (Hong Kong isolate) was the most sensitive species, their growth was strongly inhibited by TBT and the 7-d IC50 was 21 µg/l. For the three Scenedesmus species, S. dimorphus and S. platydiscus (both were isolates) had similar growth ...
应用GC－MG技术分析了深圳大亚湾大鹏澳及厦门岛南岸海域沿岸几个站位沉积物中可提取性磷脂酯结合态脂肪酸的含量和组成成份；同时采用丫啶橙荧光染色计数法测定了这些沉积物中细菌的丰度、生物量。结果表明... more 应用GC－MG技术分析了深圳大亚湾大鹏澳及厦门岛南岸海域沿岸几个站位沉积物中可提取性磷脂酯结合态脂肪酸的含量和组成成份；同时采用丫啶橙荧光染色计数法测定了这些沉积物中细菌的丰度、生物量。结果表明，在这些沉积物中细菌的生物量与磷脂酯结合态脂肪酸的组分的含量有着正相关关系。说明在环境生态研究中，可提取性磷脂作为海洋和河口沉积物中微生物生物量的生物标志物的可行性。国家自然科学基金（49676302号）及大亚湾海洋生物综合实验站（MBRS）基金（S9509号）资助
Laguncularia racemosa and Sonneratia apetala are fast-growing exotic mangrove species in Southern... more Laguncularia racemosa and Sonneratia apetala are fast-growing exotic mangrove species in Southern China and widely used for afforestation. However, the invasiveness of the two exotic species is still unclear. We compared structural and physiological traits and energy-use related traits between L. racemosa and S. apetala, and with two natives (Kandelia obovata and Aegiceras corniculatum) in northern Fujian. Results showed that leaf construction cost based on mass (CCM) and caloric values of L. racemosa were significantly lower than S. apetala, and the two natives had highest CCM. Because lower CCM, L. racemosa grew faster with a taller height (4.83 m) and wider ground diameter circumference (40.03 cm) than S. apetala (4.43 m tall and 35.63 cm wide) and the two natives (2.42 m tall and 26.78 cm wide). These findings indicated that L. racemosa could be more invasive than S. apetala in mangrove forests in northern Fujian, China where it still grew well, which deserves more attention.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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