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Tse YT, Lo HS, Tsang CW, Han J, Fang JKH, Chan SMN, Sze ETP. Quantitative analysis and risk assessment to full-size microplastics pollution in the coastal marine waters of Hong Kong. Science of The Total Environment 2023; 879:163006. [PMID: 36966838 DOI: 10.1016/j.scitotenv.2023.163006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/15/2023] [Accepted: 03/18/2023] [Indexed: 05/17/2023]
Abstract
Given the potential risk to the ecosystem, attention has increased in recent decades to the contamination of the aquatic environment by microplastics (MPs). Due to the limitations of conventional analysis methods of MPs, little is known about the size distribution and abundance of a full-size MPs from 1 μm to 5 mm. The present study quantified MPs with size ranges of 50 μm - 5 mm and 1-50 μm in the coastal marine waters from twelve locations in Hong Kong using fluorescence microscopy and flow cytometry respectively, during the end of wet (September 2021) and dry (March 2022) seasons. The average abundance of MPs with size ranges of 50 μm - 5 mm and 1-50 μm from twelve sampling locations marine surface waters were found ranging from 27 to 104 particles L-1 and 43,675-387,901 particles L-1 in the wet season respectively, and 13-36 particles L-1 and 23,178-338,604 particles L-1 in the dry season respectively. Significant temporal and spatial variations of small MPs abundance might be observed at the sampling locations, which were contributed by the influences of the estuary of Pearl River, sewage discharge points, land structure, and other anthropogenic activities. Based on the MPs abundance information, ecological risk assessment was conducted and revealed that the small MPs (< 10 μm) in coastal marine surface waters may pose potential health risks to aquatic organisms. Additional risk assessments are needed in order to determine whether or not the MPs exposure would cause health risks to the public.
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Affiliation(s)
- Yuet-Tung Tse
- School of Science and Technology, Hong Kong Metropolitan University, Homantin, Hong Kong
| | - Hoi-Shing Lo
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Chi-Wing Tsang
- Faculty of Science and Technology, Technological and Higher Education Institute of Hong Kong (THEi), Chai Wan, Hong Kong
| | - Jie Han
- School of Science and Technology, Hong Kong Metropolitan University, Homantin, Hong Kong
| | - James Kar-Hei Fang
- Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hung Hom, Hong Kong; State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Sidney Man-Ngai Chan
- School of Science and Technology, Hong Kong Metropolitan University, Homantin, Hong Kong
| | - Eric Tung-Po Sze
- School of Science and Technology, Hong Kong Metropolitan University, Homantin, Hong Kong.
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2
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Liu HM, Grist EPM, Xu XY, Lo HS, Wong ACY, Cheung SG. Microplastics pollution in the rivers of a metropolitan city and its estimated dependency on surrounding developed land. Sci Total Environ 2023; 880:163268. [PMID: 37031935 DOI: 10.1016/j.scitotenv.2023.163268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/29/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023]
Abstract
The spatial distribution and abundance of suspected microplastics (SMPs) in the surface water of a metropolitan city, as represented by four Hong Kong rivers, was studied during the dry season. Shing Mun River (SM), Lam Tsuen River (LT), and Tuen Mun River (TM) are located in urbanized areas, and SM and TM are tidal rivers. The fourth river, Silver River (SR) is situated in a rural area. TM had a significantly higher SMP abundance (53.80 ± 20.67 n/L) than the other rivers. The SMP abundance increased from upstream to downstream in non-tidal rivers (LT and SR), but not in tidal rivers (TM and SM), probably due to the tidal influence and a more homogeneous urban development along the tidal rivers. Inter-site differences in the SMP abundance were strongly correlated with the built area ratio (defined as the percentage of surrounding developed land area), human activities, and the nature of the river. About half (48.72 %) of the SMPs were <250 μm. Fibers and fragments were most abundant (>98 %), with most of them being transparent (58.54 %), black (14.68 %), or blue (12.12 %). Polyethylene terephthalate (26.96 %) and polyethylene (20.70 %) were the most common polymers. However, the MP abundance could be overestimated due to the presence of natural fibers. By contrast, an underestimation of the MP abundance could result from a smaller volume of water samples collected, due to a low filtration efficiency caused by high organic content and particle concentrations in the water. A more effective solid waste management strategy and upgrading of the sewage treatment facilities for removing microplastics are recommended to ameliorate the microplastic pollution in local rivers.
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Affiliation(s)
- H M Liu
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Eric P M Grist
- College of Engineering, Mathematics & Physical Sciences, University of Exeter, Exeter, United Kingdom
| | - X Y Xu
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China
| | - H S Lo
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - A C Y Wong
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - S G Cheung
- Department of Chemistry, City University of Hong Kong, Hong Kong, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
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3
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Po BHK, Lo HS, Cheung SG, Lai KP. Characterisation of an unexplored group of microplastics from the South China Sea: Can they be caused by macrofaunal fragmentation? Mar Pollut Bull 2020; 155:111151. [PMID: 32469771 DOI: 10.1016/j.marpolbul.2020.111151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 03/29/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Research on plastics fragmentation is important for the estimation of amount of microplastics but the biological causes for fragmentation have not been acknowledged. From microplastics collected in the beaches of Hong Kong, we revealed an abnormal type of fragment which has not been reported before. These fragments, composing about 6% of the microplastics (pellet, foam, bead, fragment) collected, were interestingly triangular in shape with at least two of the three sides being characteristically straight and resembling a cut made by compression. Objective observations have distinguished these "trimmed triangular fragments" to those triangular fragments that were fractured randomly. By comparing with additional evidence, we proposed that these trimmed fragments were the daughter pieces of macrofaunal biting. If this was so, there would be wide implications on fragmentation modeling studies for microplastics since active biting of large plastic debris has generally not been considered as a factor of plastics fragmentation.
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Affiliation(s)
- Beverly Hoi-Ki Po
- Department of Chemistry, City University of Hong Kong, Hong Kong, China; Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Hoi-Shing Lo
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Siu-Gin Cheung
- Department of Chemistry, City University of Hong Kong, Hong Kong, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China
| | - Keng-Po Lai
- Guangxi Key Laboratory of Tumor Immunology and Microenvironmental Regulation, Guilin Medical University, Guilin, PR China; Department of Chemistry, City University of Hong Kong, Hong Kong, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
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4
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Lo HS, Lee YK, Po BHK, Wong LC, Xu X, Wong CF, Wong CY, Tam NFY, Cheung SG. Impacts of Typhoon Mangkhut in 2018 on the deposition of marine debris and microplastics on beaches in Hong Kong. Sci Total Environ 2020; 716:137172. [PMID: 32059298 DOI: 10.1016/j.scitotenv.2020.137172] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/03/2020] [Accepted: 02/06/2020] [Indexed: 06/10/2023]
Abstract
Storm surge and waves associated with tropical cyclones carry significant amounts of pollutants into the marine environment. This study evaluated the effects of Typhoon Mangkhut (7-18 September 2018) on marine debris pollution including macro-debris (>2.5 cm) and microplastics (5 μm-5 mm) in Hong Kong. Sampling was repeated on four beaches, two each from protected and exposed coastal areas, spanning from the eastern to western waters before and after the cyclone. For macro-debris, an average density of 0.047 items m-2 and 0.54 items m-2 was obtained before and after the cyclone, respectively or an 11.4-fold increase, with plastic being the most dominant type (61.9-93.3% and 80.7-92.4% before and after the cyclone, respectively) among total beached debris in all four beaches. Likewise, higher mean microplastic abundances were found in the post-cyclone period (335 items kg-1 sediment) when compared with the pre-cyclone period (188 items kg-1 sediment). The depositional dynamics for both macro-debris and microplastic were site-specific due to factors such as wind direction and the associated storm surge, topography and orientation of the site, and proximity to urban areas. This study has demonstrated the role cyclone induced overwash plays on introducing plastic pollution to beach environments. Considering an increase in both the intensity and frequency of cyclone in the future due to global warming, and a tremendous increase in marine plastic debris, more research effort should be spent on this understudied problem.
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Affiliation(s)
- Hoi-Shing Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Yan-Kin Lee
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Beverly Hoi-Ki Po
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Leung-Chun Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Xiaoyu Xu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Cheuk-Fung Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Chun-Yuen Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Nora Fung-Yee Tam
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Siu-Gin Cheung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region.
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Xu X, Wong CY, Tam NFY, Lo HS, Cheung SG. Microplastics in invertebrates on soft shores in Hong Kong: Influence of habitat, taxa and feeding mode. Sci Total Environ 2020; 715:136999. [PMID: 32023520 DOI: 10.1016/j.scitotenv.2020.136999] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/09/2020] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
Microplastic (MP) pollution in the marine environment has gained much concern in recent years. This study investigated the occurrence of MPs in invertebrates collected on 18 mudflats and sandy beaches in Hong Kong and its relationships to biological taxon, feeding mode and habitat. In total 38 species of gastropods, bivalves and crabs were collected and the mean number of suspected microplastics ranged from 0 to 9.68 particles g-1 wet weight or 0 to 18.4 particles individual-1. Around 26% of the suspected microplastics were confirmed to be synthetic polymers, including CP (cellophane), PET (polyethylene terephthalate), and PA (polyamide). Microplastic fibres were the most abundant type of MPs, followed by pellets. Significantly higher abundance of suspected microplastics was found in gastropods. Since MP abundance might vary with taxon, it is recommended to include different taxonomic groups in any ecological assessment of the impact of MPs.
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Affiliation(s)
- Xiaoyu Xu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China
| | - C Y Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China
| | - Nora F Y Tam
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China
| | - Hoi-Shing Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China
| | - Siu-Gin Cheung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China.
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Li W, Lo HS, Wong HM, Zhou M, Wong CY, Tam NFY, Cheung SG. Heavy metals contamination of sedimentary microplastics in Hong Kong. Mar Pollut Bull 2020; 153:110977. [PMID: 32275534 DOI: 10.1016/j.marpolbul.2020.110977] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 02/10/2020] [Accepted: 02/10/2020] [Indexed: 06/11/2023]
Abstract
This is the first study of heavy metals (As, Zn, Cd, Ni, Fe, Mn, Cu) contamination of microplastics on sandy beaches in Hong Kong. Three study sites are located in the eastern waters (Pak Lap Wan, Stanley Bay, Tung Lung Chau) and the other three in the western waters (Tai Pai Tsui, Ha Pak Nai, Shui Hau Wan). The three most abundant types of microplastics were polyethylene (42.2%), polypropylene (23.3%) and polystyrene (19.5%). The median concentration of Fe (302 mg kg-1) was the highest and followed by Zn (19.6 mg kg-1) and Mn (18.6 mg kg-1). Very low concentrations of Cu (0.89 mg kg-1), Ni (0.15 mg kg-1), As (<LOD) and Cd (<LOD) were measured. The western sites have significantly higher concentrations of Ni, Fe, Mn and Cu than the eastern sites, indicating that Pearl River was likely to be a major source of heavy metals on microplastics. In view of a continual increase in the abundance of microplastics in the marine environment and its potential impacts on marine organisms, immediate actions should be taken in establishing long term monitoring programs for heavy metals associated with microplastics. In-depth research on the mechanisms of adsorption and desorption processes between metals and microplastics will help assess the associated risks to both human health and the environment.
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Affiliation(s)
- Wenjie Li
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Hoi-Shing Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Ho-Man Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Man Zhou
- Research Institute for Environmental Innovation (Suzhou), Tsinghua, RIET, Jinfeng Road, Suzhou, China
| | - Chun-Yuen Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Nora Fung-Yee Tam
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Siu-Gin Cheung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region.
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7
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Lo HS, Wong LC, Kwok SH, Lee YK, Po BHK, Wong CY, Tam NFY, Cheung SG. Field test of beach litter assessment by commercial aerial drone. Mar Pollut Bull 2020; 151:110823. [PMID: 32056615 DOI: 10.1016/j.marpolbul.2019.110823] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/25/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
The visual survey is the most common method to quantify and characterize beach litter. However, it is very labor intensive and difficult to carry out on beaches which are remote or difficult to access. We suggest an alternative approach for assessing beach litter using an unmanned aerial vehicle (UAV), or aerial drone, with automated image requisition and processing. Litter of different sizes, colours, and materials were placed randomly on two beaches. Images of beaches with different substrates were obtained by the drone at different operating heights and light conditions and litter on the beaches was identified from the photos by untrained personnel. The quantification of beach litter using the drone was three times faster than that by visual census. This study has demonstrated the potential of using the drone as a cost-effective and an efficient sampling method in routine beach litter monitoring programs.
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Affiliation(s)
- Hoi-Shing Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Leung-Chun Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Shu-Hin Kwok
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Yan-Kin Lee
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Beverly Hoi-Ki Po
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Chun-Yuen Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Nora Fung-Yee Tam
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Siu-Gin Cheung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region.
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8
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Lo HS, Wong CY, Tam NFY, Cheung SG. Spatial distribution and source identification of hydrophobic organic compounds (HOCs) on sedimentary microplastic in Hong Kong. Chemosphere 2019; 219:418-426. [PMID: 30551108 DOI: 10.1016/j.chemosphere.2018.12.032] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 11/27/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
The spatial distribution, composition and source of hydrophobic organic compounds (HOCs) including polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs) of the sedimentary microplastics (0.25-5 mm) in Hong Kong were investigated. The concentration of ΣPAHs ranged between 70.8 and 1509 ng g-1 with inter-site differences although the regional difference was insignificant, indicating localised pyrolytic and petrogenic input of PAHs. The concentration of ΣPCBs (13-1083 ng g-1) varied with both study sites and regions with higher concentrations obtained in the western waters, possibly due to the input from Pearl River. Significantly higher concentrations of OCPs on eastern shores highlighted fishing and aquaculture activities in South China Sea a potential major source of OCPs. DDT and its metabolites (DDX, ranged from 1.96 to 626 ng g-1) were the dominant forms of OCPs (45%-80%). Since most of the DDX existed as DDT, this suggested that there was a fresh input of DDT into the microplastics. As microplastics and HOCs cannot be removed effectively from the environment, reduction of potential ecotoxicological risks should rely on minimizing the use of plastics and HOCs.
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Affiliation(s)
- Hoi-Shing Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Chun-Yuen Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Nora Fung-Yee Tam
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Siu-Gin Cheung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region.
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Lo HS, Xu X, Wong CY, Cheung SG. Comparisons of microplastic pollution between mudflats and sandy beaches in Hong Kong. Environ Pollut 2018; 236:208-217. [PMID: 29414341 DOI: 10.1016/j.envpol.2018.01.031] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/12/2018] [Accepted: 01/12/2018] [Indexed: 06/08/2023]
Abstract
Most of the previous studies of microplastic pollution on coastal habitats focused on high energy beaches although low energy areas such as mudflats are supposed to retain more microplastics, not to mention that mudflats are biologically more diverse. We quantified and characterized microplastics from 10 mudflats and 10 sandy beaches in Hong Kong spanning from the eastern to western waters. Sediment samples were collected at 1.0 m and 1.5 m above chart datum (CD) and at the strandline. Abundance of microplastics ranged between 0.58 and 2116 items kg-1 sediment with that on mudflats being ten times more than on beaches. Polyethylene (46.9%) was the most abundant and followed by polypropylene (13.8%) and polyethylene terephthalate (13.5%). Expanded polystyrene was the most abundant in the strandline samples but not at 1.0 m and 1.5 m above CD. Although previous studies have concluded that the input from Pearl River is a major source of microplastics on Hong Kong shores, this study has demonstrated that the contribution of local pollution sources such as discharge from sewage treatment plants to microplastic pollution should not be neglected.
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Affiliation(s)
- Hoi-Shing Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, PR China
| | - Xiaoyu Xu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region
| | - Chun-Yuen Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region; Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, PR China
| | - Siu-Gin Cheung
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Hong Kong Special Administrative Region.
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Ng SW, Chung LH, Yeung CF, Lo HS, Shek HL, Kang TS, Leung CH, Ma DL, Wong CY. Frontispiece: Metalated Chromene and Chromone Complexes: pH Switchable Metal-Carbon Bonding Interaction, Photo-triggerable Chromone Delivery Application, and Antioxidative Activity. Chemistry 2018. [DOI: 10.1002/chem.201880864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sze-Wing Ng
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
| | - Lai-Hon Chung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Chi-Fung Yeung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hoi-Shing Lo
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hau-Lam Shek
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Dik-Lung Ma
- Department of Chemistry; Hong Kong Baptist University, Kowloon Tong; Hong Kong SAR P.R. China
| | - Chun-Yuen Wong
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
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Chung LH, Ng SW, Yeung CF, Shek HL, Tse SY, Lo HS, Chan SC, Tse MK, Yiu SM, Wong CY. Ruthenium–indolizinone complexes as a new class of metalated heterocyclic compounds: insight into unconventional alkyne activation pathways, revelation of unexpected electronic properties and exploration of medicinal application. Dalton Trans 2018; 47:12838-12842. [DOI: 10.1039/c8dt02408a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The first examples of metal–indolizinone complexes prepared by Ru-assisted activation of pyridine-tethered alkynes exhibit moderate cytotoxicity against several human cancer cell lines.
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Affiliation(s)
- Lai-Hon Chung
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
| | - Sze-Wing Ng
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
- State Key Laboratory of Millimeter Waves
| | - Chi-Fung Yeung
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
- State Key Laboratory of Millimeter Waves
| | - Hau-Lam Shek
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
| | - Sheung-Ying Tse
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
| | - Hoi-Shing Lo
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
- Shenzhen Research Institute
| | - Siu-Chung Chan
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
| | - Man-Kit Tse
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
| | - Shek-Man Yiu
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
| | - Chun-Yuen Wong
- Department of Chemistry
- City University of Hong Kong
- Kowloon
- Hong Kong SAR
- State Key Laboratory of Millimeter Waves
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12
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Ng SW, Chung LH, Yeung CF, Lo HS, Shek HL, Kang TS, Leung CH, Ma DL, Wong CY. Metalated Chromene and Chromone Complexes: pH Switchable Metal-Carbon Bonding Interaction, Photo-triggerable Chromone Delivery Application, and Antioxidative Activity. Chemistry 2017; 24:1779-1783. [DOI: 10.1002/chem.201705450] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Sze-Wing Ng
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
| | - Lai-Hon Chung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Chi-Fung Yeung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hoi-Shing Lo
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hau-Lam Shek
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Dik-Lung Ma
- Department of Chemistry; Hong Kong Baptist University, Kowloon Tong; Hong Kong SAR P.R. China
| | - Chun-Yuen Wong
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
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13
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Xu XY, Lee WT, Chan AKY, Lo HS, Shin PKS, Cheung SG. Microplastic ingestion reduces energy intake in the clam Atactodea striata. Mar Pollut Bull 2017; 124:798-802. [PMID: 28038767 DOI: 10.1016/j.marpolbul.2016.12.027] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 11/29/2016] [Accepted: 12/11/2016] [Indexed: 05/27/2023]
Abstract
The effects of microplastic concentrations (10itemsl-1 and 1000itemsl-1) on the physiological responses of Atactodea striata (clearance rate, absorption efficiency, respiration rate) were investigated. The fates of ingested microplastics and the efficiency of depuration in removing ingested microplastics were also studied. A. striata ingested microplastics and the clearance rate was reduced at high concentration of microplastics. Since the respiration rate and absorption efficiency remained unchanged in exposed A. striata, reduction in the clearance rate would reduce the energy intake. Ingestion and retention of microplastics in the body were further limited by the production of pseudofaeces and faeces, and depuration in clean water, resulting in a very small amount of microplastics stored in the body of the clam.
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Affiliation(s)
- X-Y Xu
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - W T Lee
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - A K Y Chan
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - H S Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - P K S Shin
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - S G Cheung
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
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14
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Lo HS, Lo KW, Yeung CF, Wong CY. Rapid visual and spectrophotometric nitrite detection by cyclometalated ruthenium complex. Anal Chim Acta 2017; 990:135-140. [DOI: 10.1016/j.aca.2017.07.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 06/15/2017] [Accepted: 07/09/2017] [Indexed: 12/25/2022]
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15
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Yeung CF, Chung LH, Lo HS, Chiu CH, Cai J, Wong CY. Isolation of Ruthenium–Indoline and −Indole Zwitterion Complexes: Insight into the Metal-Induced Cyclization of Aniline-Tethered Alkynes and Strategy to Lower the Activation Barrier of Metal−Vinylidene Formation. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00211] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chi-Fung Yeung
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Lai-Hon Chung
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Hoi-Shing Lo
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Chun-Hong Chiu
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Jialin Cai
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Chun-Yuen Wong
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
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Tsui WK, Chung LH, Tsang WH, Yeung CF, Chiu CH, Lo HS, Wong CY. Synthesis, Spectroscopic and Theoretical Studies of Ruthenafuran and Osmafuran Prepared by Activation of Ynone in Alcohol. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Wai-Kuen Tsui
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Lai-Hon Chung
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Wai-Him Tsang
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Chi-Fung Yeung
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Chun-Hong Chiu
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Hoi-Shing Lo
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
| | - Chun-Yuen Wong
- Department
of Biology and
Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China
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Abstract
AIMS To create a fast, sensitive and specific method for identifying Fusarium oxysporum f. sp. cucumerinum and F. o. luffae. METHODS AND RESULTS Specific DNA bands were selected as probes from RAPD profiles of 13 formae speciales of F. oxysporum. The forma specialis-specific probe OPC18300c and OPC18520f could be used to identify F. o. cucumerinum and F. o. luffae by RAPD-PCR followed dot blot hybridization, respectively. CONCLUSIONS A specific method for identifying F. o. cucumerinum and F. o. luffae was achieved. SIGNIFICANCE AND IMPACT OF THE STUDY F. oxysporum formae speciales identification with a DNA probe can be relatively rapid and provides a method to identify the pathogen without host inoculation tests.
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Affiliation(s)
- P H Wang
- Department of Microbiology, Soochow University, Taipei, Taiwan, R.O.C.
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Lo HS, Chen CH, Hogan EL, Kao KP, Wang V, Yan SH. Genetic polymorphism and Parkinson's disease in Taiwan: study of debrisoquine 4-hydroxylase (CYP2D6). J Neurol Sci 1998; 158:38-42. [PMID: 9667775 DOI: 10.1016/s0022-510x(98)00094-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Debrisoquine 4-hydroxylase (CYP2D6) is one of the cytochrome P450 enzyme families that catalyze the breakdown of a variety of exogenous and endogenous compounds. Previous reports have suggested that genetic polymorphisms of debrisoquine 4-hydroxylase are associated with susceptibility to Parkinson's disease (PD) in Caucasians. To determine if CYP2D6 also confers susceptibility to PD in Chinese patients, we carried out a study of genetic association using three polymorphic markers of the CYP2D6 gene, 188C/T, 1934G/A (mutant B), and 4268G/C. No differences of allele or genotype frequencies of these three polymorphisms were detected upon comparison of primary PD patients (n=53) with normal controls (n=94). The 1934A allele (mutant B), which accounts for the majority of poor metabolizers in Caucasians, is extremely rare in Chinese. Our data do not support the suggestion that the CYP2D6 gene is related to PD susceptibility in Chinese.
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Affiliation(s)
- H S Lo
- Department of Neuropsychiatry, Taiwan Adventist Hospital, Taipei
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Bender L, Lo HS, Lee H, Kokojan V, Peterson V, Bender A. Associations among PH and SH3 domain-containing proteins and Rho-type GTPases in Yeast. J Biophys Biochem Cytol 1996; 133:879-94. [PMID: 8666672 PMCID: PMC2120828 DOI: 10.1083/jcb.133.4.879] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The src homology region 3 (SH3) domain-bearing protein Bem1p and the Rho-type GTPase Cdc42p are important for bud emergence in Saccharomyces cervisiae. Here, we present evidence that through its second SH3 domain, Bem1p binds to the structurally and functionally similar proteins Boi1p and Boi2p, each of which contain an SH3 and pleckstrin homology (PH) domain. Deletion of BOI1 and BO12 together leads to impaired morphogenesis and poor ability. A PH domain-bearing segment of Boi1p that lacks the Bem1p-binding site is necessary and sufficient for function. This segment of Boi1p displays a two-hybrid interaction with Cdc42p, suggesting that Boi1p either binds directly to or is part of a larger complex that contains Cdc42p. Consistent with these possibilities, overexpression of Boi1p inhibits bud emergence, but this inhibition is counteracted by cooverexpression of Cdc42p. Increased expression of the Rho-type GTPase Rho3p, which is implicated in bud growth defects of boil boi2 mutants, suggesting that Boi1p and Boi2p may also play roles in the activation or function of Rho3p. These findings provide an example of a tight coupling in function between PH domain-bearing proteins and both Rho-type GTPases and SH3 domain-containing proteins, and they raise the possibility that Boi1p and Boi2 play a role in linking the actions of Cdc42p and Rho3p.
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Affiliation(s)
- L Bender
- Department of Biology, Indiana University, Bloomington 47405, USA
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Abstract
1. Pentatrichomonas hominis was found incapable of de novo synthesis of purines. 2. Pentatrichomonas hominis can salvage adenine, guanine, hypoxanthine, adenosine, guanosine and inosine, but not xanthine for the synthesis of nucleotides. 3. HPLC tracing of radiolabelled purines or purine nucleosides revealed that adenine, adenosine and hypoxanthine are incorporated into adenine nucleotides and IMP through a similar channel while guanine and guanosine are salvaged into guanine nucleotides via another route. There appears to be no direct interconversion between adenine and guanine nucleotides. Interconversion between AMP and IMP was observed. 4. Assays of purine salvage enzymes revealed that P. hominis possess adenosine kinase; adenosine, guanosine and inosine phosphotransferases; adenosine, guanosine and inosine phosphorylases and AMP deaminase.
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Affiliation(s)
- P Tang
- Department of Parasitology and Tropical Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China
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Yang TC, Wang SY, Lee RZ, Lo HS, Yueh FL. Cervical chlamydial infection in gynecologic outpatients. Zhonghua Yi Xue Za Zhi (Taipei) 1988; 41:63-6. [PMID: 3048603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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22
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Chen CC, Shou L, Hwang LL, Tang P, Tu WC, Lo HS. Persistence of hepatitis B viral antigens in Culex quinquefasciatus. Southeast Asian J Trop Med Public Health 1987; 18:44-51. [PMID: 3660067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Culex quinquefasciatus mosquitoes were fed on or inoculated with blood or serum positive for hepatitis B viral antigens and pools of mosquitoes were tested by radioimmunoassay daily for 3 weeks after exposure to detect the viral antigens. Hepatitis B surface antigen (HBsAg) was detectable up to 3 weeks, while hepatitis B e antigen (HBeAg) persisted only for 3 days in mosquitoes after feeding on hepatitis B viral antigens-positive blood. Mosquitoes inoculated with serum were HBsAg-positive for 3 weeks and HBeAg positive for 4 days after inoculation. These results suggest that biological multiplication of hepatitis B virus did not occur in these mosquitoes. The possibility of mechanical transmission of hepatitis B antigens by mosquitoes is discussed.
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Affiliation(s)
- C C Chen
- Department of Parasitology and Tropical Medicine, National Defense Medical Center, Taipei, Taiwan, R.O.C
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23
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Lo HS, Wang CC. Purine salvage in Entamoeba histolytica. J Parasitol 1985; 71:662-9. [PMID: 2865346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Pulse-labeling of the nucleotide pool in Entamoeba histolytica with radioactive precursors, and subsequent high performance liquid chromatographic (HPLC) analysis of the radiolabeled nucleotides, indicate that E. histolytica is incapable of de novo synthesis of purine nucleotides. Hypoxanthine, inosine and xanthine could not be converted to nucleotides in E. histolytica, which suggests the absence of interconversion between adenine nucleotides and guanine nucleotides through formation of IMP. Adenosine was actively incorporated into nucleotides at an initial rate of 130 pmoles per minute per 10(6) trophozoites. Adenine, guanosine and guanine were also incorporated at much lower rates. The rate of adenine incorporation was enhanced by the presence of guanosine; the rate of guanine incorporation was significantly increased by adenosine. These stimulatory effects suggest that the ribose moiety of adenosine or guanosine can be transferred to another purine base to form a new nucleoside, and that the purine nucleosides are the immediate precursors of E. histolytica nucleotides. HPLC results showed that the radiolabel in adenine was exclusively incorporated into adenine nucleotides and that guanine was found only among guanine nucleotides, whereas the radioactivity associated with the ribose moiety of adenosine or guanosine was distributed among both adenine and guanine nucleotides.
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Lo HS, Chang CJ. Purification and properties of NADP-linked, alcohol dehydrogenase from Entamoeba histolytica. J Parasitol 1982; 68:372-7. [PMID: 6284905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
An NADP-linked, alcohol dehydrogenase from Entamoeba histolytica was purified to apparent homogeneity by Blue Sepharose affinity chromatography. Molecular weights of 130,000 and 30,000 were estimated by gel filtration and by sodium dodecyl sulfate polyacrylamide gel electrophoresis, respectively, suggesting that the enzyme is a tetramer. The enzyme exhibited more than 20-fold selectivity for NADP(H) over NAD(H). Although the purified enzyme acts on both primary and secondary alcohols, higher activity was found with secondary alcohols.
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Lo HS. Glucose dissimilation in Entamoeba histolytica. Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi 1981; 14:173-178. [PMID: 6269810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The endproducts of glucose dissimilation in Entamoeba histolytica were found to be carbon dioxide, acetate and ethanol. This organism possesses the same Embden-Meyerhof intermediates as found in most investigated organisms. In its glucose-to-pyruvate pathway several unusual features were demonstrated. The pyruvate-to-acetate and pyruvate-to-ethanol pathways are also unique as compared with that of other organisms. The distinctive properties of the metabolic enzymes provide the basis for the development of new chemotherapeutic agents against this parasitic protozoa.
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Shaio MF, Lo HS, Huang SW. [Trichomonas hominis: isolation and axenic cultivation (author's transl)]. Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi 1981; 14:73-7. [PMID: 7030663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Recently we have isolated Trichomonas hominis from diarrheic stools of a patient and established it in an axenic culture medium. The procedures are as follows: Diarrheic stool containing numerous trophozoites was first inoculated into the TYM (Trypticase Yeast extract Maltose) medium of Diamond (1975) to establish a polyxenic culture. Antibiotics, containing penicillin (1000 U/ml), streptomycin (1000 micrograms/ml), and cephalosporin (20 micrograms/ml) were added to prevent overgrowth of bacteria and fungi. After several passages, a specially-designed culture-tube was employed to separate T. hominis from the contaminants. The isolated T. hominis was then introduced into the modified TYI-S-33 (Trypticase Yeast extract Iron-Serum-33) medium of Diamond (1978). The organism established itself readily to this axenic culture medium. Sterility tests employing fluid thioglycollate, nutrient broth, and blood agar plate gave negative results indicating the absence of contaminants. The axenic culture of T. hominis provides us with a source of pure flagellates for biological, biochemical, and immunological studies.
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Abstract
The serum concentration and composition of gangliosides were examined in 80 humans including 10 normal subjects. A significant increase was found in the total gangliosides of serum in 7 patients with cerebral astrocytomas. There was also an increased percentage of serum gangliosides with simpler structure, particularly GM3. The serum of patients with other intracranial tumors, including pituitary adenomas, ependymoma, teratoma, and metastases, did not show an increase in total ganglioside; however the pattern of simplification was found in these and in a few patients with extracranial tumors as well. The findings suggest that astrocytoma tumors shed sialoglycolipids into the circulation, and their assay may be useful in monitoring oncological therapy.
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Abstract
Riboflavin was found to be essential for the cultivation of axenic Entamoeba histolytica. This is the first demonstration of a flavin requirement by the organism. Panmede, the principal source of flavins in the axenic medium, was treated with activated carbon to remove flavins. Medium made with this flavin-deficient Panmede, and supplemented with ribonucleic acid failed to support the multiplication of amebae in serial subculture, but did so when riboflavin was added. The concentration of riboflavin required to achieve maximal growth was about 1.3 microgram per ml medium. Studies on riboflavin uptake revealed that amebae lack a high-affinity transport system for this vitamin. The rate of riboflavin uptake was equivalent to the rate of pinocytotic uptake of fluid as previously determined.
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Abstract
The pyruvate-to-ethanol pathway in Entamoeba histolytica is unusual when compared with most investigated organisms. Pyruvate decarboxylase (EC 4.1.1.1), a key enzyme for ethanol production, is not found. Pyruvate is converted into acetyl-CoA and CO2 by the enzyme pyruvate synthase (EC 1.2.7.1), which has been demonstrated previously in this parasitic amoeba. Acetyl-CoA is reduced to acetaldehyde and CoA by the enzyme aldehyde dehydrogenase (acylating) (EC 1.2.1.10) at an enzyme activity of 9 units per g of fresh cells with NADH as a reductant. Acetaldehyde is further reduced by either a previously identified NADP+-linked alcohol dehydrogenase or by a newly found NAD+-linked alcohol dehydrogenase at an enzyme activity of 136 units per g of fresh cells. Ethanol is identified as the product of soluble enzymes of amoeba acting on pyruvate or acetyl-CoA. This result is confirmed by radioactive isotopic, spectrophotometric and gas-chromatographic methods.
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Reeves RE, Warren LG, Susskind B, Lo HS. An energy-conserving pyruvate-to-acetate pathway in Entamoeba histolytica. Pyruvate synthase and a new acetate thiokinase. J Biol Chem 1977; 252:726-31. [PMID: 13076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Under anaerobic conditions, cells of Entamoeba histolytica grown with bacteria produce H2 and acetate while cells grown axenically produce neither. Aerobically, acetate is produced and O2 is consumed by amebae from either type of cells. Centrifuged extracts, 2.4 x 106 x g x min, from both types of cells contain pyruvate synthase (EC 1.2.7.1) and an acetate thiokinase which, together, form a system capable of converting pyruvate to acetate. Pyruvate synthase catalyzes the reaction: pyruvate + CoA leads to CO2 + acetyl-CoA + 2E. Electron acceptors which function with this enzyme are FAD, FMN, riboflavin, ferredoxin, and methyl viologen, but not NAD or NADP. The amebal acetate thiokinase catalyzes the reaction acetyl-CoA + ADP + Pi leads to acetate + ATP + CoA. For this apparently new enzyme we suggest the trivial name acetyl-CoA-synthetase (ADP-forming). Extracts from axenic amebae do not contain hydrogenase, but extracts from cells grown with bacteria do. It is postulated that in bacteria-grown amebae electrons generated at the pyruvate synthase step are utilized anaerobically to produce H2 via the hydrogenase and that the acetyl-CoA is converted to acetate in an energy-conserving step catalyzed by amebal acetyl-CoA synthetase. Aerobically, cells grown under either regimen may utilize the energy-conserving pyruvate-to-acetate pathway since O2 then serves as the ultimate electron acceptor.
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Reeves RE, Warren LG, Susskind B, Lo HS. An energy-conserving pyruvate-to-acetate pathway in Entamoeba histolytica. Pyruvate synthase and a new acetate thiokinase. J Biol Chem 1977. [DOI: 10.1016/s0021-9258(17)32778-3] [Citation(s) in RCA: 124] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
The classification and, therefore, identification of Chromobacterium violaceum has been based upon its ability to produce a violet pigment. Although the organism may yield non-pigmented variants when subcultured on artificial media, the isolation of non-pigmented strains from pathological tissues or from nature had not been reported. With a method established for the identification of C. violaceum regardless of violet pigmentation, non-pigmented strains were isolated from nature. The presence of non-pigmented strains of C. violaceum in nature is of significance to taxonomy and clinical bacteriology. Pigmentation cannot be held as an essential characteristic of the definition of the genus Chromobacterium and gives credence to the suspicion of Sneath (1960, 1966) that the genus is not a natural one. Non-pigmented strains may have been isolated from clinical material but wrongly identified as belonging to other genera of non-pigmented Gram-negative bacilli and regarded as not being pathogenic.
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Sivendra R, Lo HS, Lim KT. Letter: Carbohydrate fermentation, KIA, and TSI agar reactions of Chromobacterium violaceum. Am J Clin Pathol 1975; 64:421-2. [PMID: 1163494 DOI: 10.1093/ajcp/64.3.421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Fan PC, Wang YC, Lin JC, Lo HS, King ML. [Control of Bancroftian filariasis by common salt medicated with diethylcarbamazine on Little Kinmen (Quemoy) Island. 1. Epidemiological study]. Zhonghua Min Guo Wei Sheng Wu Xue Za Zhi 1975; 8:36-58. [PMID: 238801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Lo HS, Wilson CW. Letter: Anemia in the elderly. Br Med J 1973; 4:612. [PMID: 4758528 PMCID: PMC1587745 DOI: 10.1136/bmj.4.5892.612-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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38
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Omar AR, Lo HS, Teoh KC. Syncytia and inclusion bodies in acute Marek's disease. Aust Vet J 1973; 49:319-20. [PMID: 4722891 DOI: 10.1111/j.1751-0813.1973.tb06817.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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