The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium Toxicity
Production of exopolymers is one of heavy metal resistance mechanisms in bacteria. Ralstonia sp. TAK1, a cadmium-resistant bacterium, was isolated from a high cadmium (Cd) contaminated soil at the zinc mine, Tak province, Thailand. The bacterium was cultivated in LB broth and its growth was monitore...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Thai Society of Higher Eduction Institutes on Environment
2008-07-01
|
| Series: | EnvironmentAsia |
| Subjects: | |
| Online Access: | http://www.tshe.org/ea/pdf/vol1%20no2%20p37-42.pdf |
| _version_ | 1818991901811933184 |
|---|---|
| author | Anchulee Watcharamusik Benjaphorn Prapagdee |
| author_facet | Anchulee Watcharamusik Benjaphorn Prapagdee |
| author_sort | Anchulee Watcharamusik |
| collection | DOAJ |
| description | Production of exopolymers is one of heavy metal resistance mechanisms in bacteria. Ralstonia sp. TAK1, a cadmium-resistant bacterium, was isolated from a high cadmium (Cd) contaminated soil at the zinc mine, Tak province, Thailand. The bacterium was cultivated in LB broth and its growth was monitored. The yields of exopolymers were measured by the phenol-sulfuric method at different growth phases. The levels of Cd resistance were quantitatively determined by survival cell assay. The highest amount of exopolymers (0.69 mg glucose equivalent/ mg dry weight) was found at the stationary phase and sharply decreased at the late-stationary phase. In addition to high production of exopolymers at the stationary phase, Ralstonia sp. TAK1 was more resistant to Cd than that of exponential phase cells. These results suggested that the resistance to Cd toxicity in Ralstonia sp. TAK1 at the stationary phase is mediated by exopolymer production. Contradictorily, there was no correlation between Cd resistance level and exopolymer production of cells at exponential phase indicating that other mechanism(s) is responsible for Cd resistance of exponential phase cells. In addition, 0.4 mM CdCl2 was able to induce the increasing of exopolymers at the mid-exponential phases compared to uninduced cells. Exopolymer production of Cd-induced cells was constant from the mid-stationary to late-stationary phase. However, the highest exopolymers was found in uninduced cells at the stationary phase. |
| first_indexed | 2024-12-20T20:17:38Z |
| format | Article |
| id | doaj.art-5ce2ec4761b44d489b339c79fa08cfdf |
| institution | Directory Open Access Journal |
| issn | 1906-1714 |
| language | English |
| last_indexed | 2024-12-20T20:17:38Z |
| publishDate | 2008-07-01 |
| publisher | Thai Society of Higher Eduction Institutes on Environment |
| record_format | Article |
| series | EnvironmentAsia |
| spelling | doaj.art-5ce2ec4761b44d489b339c79fa08cfdf2022-12-21T19:27:40ZengThai Society of Higher Eduction Institutes on EnvironmentEnvironmentAsia1906-17142008-07-01123742The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium ToxicityAnchulee WatcharamusikBenjaphorn PrapagdeeProduction of exopolymers is one of heavy metal resistance mechanisms in bacteria. Ralstonia sp. TAK1, a cadmium-resistant bacterium, was isolated from a high cadmium (Cd) contaminated soil at the zinc mine, Tak province, Thailand. The bacterium was cultivated in LB broth and its growth was monitored. The yields of exopolymers were measured by the phenol-sulfuric method at different growth phases. The levels of Cd resistance were quantitatively determined by survival cell assay. The highest amount of exopolymers (0.69 mg glucose equivalent/ mg dry weight) was found at the stationary phase and sharply decreased at the late-stationary phase. In addition to high production of exopolymers at the stationary phase, Ralstonia sp. TAK1 was more resistant to Cd than that of exponential phase cells. These results suggested that the resistance to Cd toxicity in Ralstonia sp. TAK1 at the stationary phase is mediated by exopolymer production. Contradictorily, there was no correlation between Cd resistance level and exopolymer production of cells at exponential phase indicating that other mechanism(s) is responsible for Cd resistance of exponential phase cells. In addition, 0.4 mM CdCl2 was able to induce the increasing of exopolymers at the mid-exponential phases compared to uninduced cells. Exopolymer production of Cd-induced cells was constant from the mid-stationary to late-stationary phase. However, the highest exopolymers was found in uninduced cells at the stationary phase.http://www.tshe.org/ea/pdf/vol1%20no2%20p37-42.pdfcadmium-resistance mechanismexopolymersEalstonia sp. |
| spellingShingle | Anchulee Watcharamusik Benjaphorn Prapagdee The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium Toxicity EnvironmentAsia cadmium-resistance mechanism exopolymers Ealstonia sp. |
| title | The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium Toxicity |
| title_full | The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium Toxicity |
| title_fullStr | The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium Toxicity |
| title_full_unstemmed | The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium Toxicity |
| title_short | The Role of Exopolymers in Protection of Ralstonia sp., a Cadmium-resistant Bacterium, from Cadmium Toxicity |
| title_sort | role of exopolymers in protection of ralstonia sp a cadmium resistant bacterium from cadmium toxicity |
| topic | cadmium-resistance mechanism exopolymers Ealstonia sp. |
| url | http://www.tshe.org/ea/pdf/vol1%20no2%20p37-42.pdf |
| work_keys_str_mv | AT anchuleewatcharamusik theroleofexopolymersinprotectionofralstoniaspacadmiumresistantbacteriumfromcadmiumtoxicity AT benjaphornprapagdee theroleofexopolymersinprotectionofralstoniaspacadmiumresistantbacteriumfromcadmiumtoxicity AT anchuleewatcharamusik roleofexopolymersinprotectionofralstoniaspacadmiumresistantbacteriumfromcadmiumtoxicity AT benjaphornprapagdee roleofexopolymersinprotectionofralstoniaspacadmiumresistantbacteriumfromcadmiumtoxicity |