Arsenic effectively improves the degradation of fluorene by Rhodococcus sp. 2021 under the combined pollution of arsenic and fluorene.

The performance of bacterial strains in executing degradative functions under the coexistence of heavy metals/heavy metal-like elements and organic contaminants is understudied. In this study, we isolated a fluorene-degrading bacterium, highly arsenic-resistant, designated as strain 2021, from contaminated soil at the abandoned site of an old coking plant. It was identified as a member of the genus Rhodococcus sp. strain 2021 exhibited efficient fluorene-degrading ability under optimal conditions of 400 mg/L fluorene, 30 °C, pH 7.0, and 250 mg/L trivalent arsenic. It was noted that the addition of arsenic could promote the growth of strain 2021 and improve the degradation of fluorene - a phenomenon that has not been described yet. The results further indicated that strain 2021 can oxidize As3+ to As5+; here, approximately 13.1% of As3+ was converted to As5+ after aerobic cultivation for 8 days at 30 °C. The addition of arsenic could greatly up-regulate the expression of arsR/A/B/C/D and pcaG/H gene clusters involved in arsenic resistance and aromatic hydrocarbon degradation; it also aided in maintaining the continuously high expression of cstA that codes for carbon starvation protein and prmA/B that codes for monooxygenase. These results suggest that strain 2021 holds great potential for the bioremediation of environments contaminated by a combination of arsenic and polycyclic aromatic hydrocarbons. This study provides new insights into the interactions among microbes, as well as inorganic and organic pollutants.

[Analysis the clinic and cytogenetics of myelodysplastic syndrome].

OBJECTIVE: To analysis the relationship among cytogenetics, morphology and prognosis of the myelodysplastic syndrome (MDS) patients. METHODS: Cytogenetics analysis of bone marrow cells was performed by direct method and/or 24 h culture method. The karyotype was analysed by R banding technique. RESULTS: Out of the 50 MDS patients, 22 were found with abnormal karyotype: two of them were +8, four of them were -7, four of them were 5q-, nine of them were 7q-, two of them were 20q- and one of them was 6q-. There are six patients had complex changes in chromosome. CONCLUSION: 5q-, -7, 7q- are the most classic translocation in the MDS. The patients with 5q- have better prognosis and the patients with -7, 7q- have worse prognosis. Cytogenetics is very important in the MDS's diagnosis, progress and prognosis.