Role of divalent metals Cu2+ and Zn2+ in Microcystis aeruginosa proliferation and production of toxic microcystins.

Cu2+ and Zn2+, two ubiquitous metals in water environments, can widely trigger algae blooms at favourable environmental conditions. This paper elucidates the roles of Cu2+ and Zn2+ in the proliferation of Microcystis aeruginosa (M. aeruginosa) and synthesis of Microcystins (MCs). Findings indicate significant influences of increasing Cu2+ and Zn2+ concentrations on cell proliferation at limited available phosphorus concentrations of less than 0.1 mg/L. By contrast, Cu2+ and Zn2+ notably affected MCs production at all the inoculated phosphorus concentrations. The critical concentrations of 1 µg/L and 5 µg/L for Cu2+ and Zn2+, respectively, are determined to trigger rapid cell proliferation and MCs production. Furthermore, the impacts of Cu2+ and Zn2+ on nitrogen absorption and, subsequently, on amino acids (AAs) formation in cells, is likely key in MCs synthesis. The two AAs Alanine (Ala) and glutamic acid (Glu) demonstrate the most notable variations with the concentrations of Cu2+ & Zn2+.

On the risks from sediment and overlying water by replenishing urban landscape ponds with reclaimed wastewater.

The extensive use of reclaimed wastewater (RW) as a source of urban landscape pond replenishment, stimulated by the lack of surface water (SW) resources, has raised public concern. Greater attention should be paid to pond sediments, which act as 'sinks' and 'sources' of contaminants to the overlying pond water. Three ponds replenished with RW (RW ponds) in three Chinese cities were chosen to investigate 22 indices of sediment quality in four categories: eutrophication, heavy metal, ecotoxicity and pathogens risk. RW ponds were compared with other ponds of similar characteristics in the same cities that were replenished with SW (SW ponds). Our results show a strong impact of RW to the eutrophication and pathogenic risks, which are represented by organic matter, water content, total nitrogen, total phosphorus and phosphorus fractions, and pathogens. In particular, total phosphorus concentrations in the RW pond sediments were, on average, 50% higher than those of SW ponds. Moreover, the content of phosphorus, extracted by bicarbonate/dithionite (normally represented by BD-P) and NaOH (NaOH-P), were 2.0- and 2.83-times higher in RW ponds, respectively. For pathogens, the concentrations of norovirus and rotavirus in RW pond sediments were, on average, 0.52 and 0.30- log times those of SW ponds. The duration of RW replenishment was proved to have a marked impact on the eutrophication and pathogens risks from sediments. The continued use of RW for replenishment increases the eutrophication risk, and the pathogens risk, especially by viral pathogens, becomes greater.

Study on mRNA and protein expressions of organic anion transporting polypeptide (oatp2b1) in rats with high fat diet and overstrain induced Pi deficiency syndrome / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore roles of mRNA and protein expressions of organic anion transporting polypeptide (oatp2b1) of rats with high fat diet and overstrain induced Pi deficiency syndrome in the transporting of damp turbidity.</p><p><b>METHODS</b>Totally 24 SD rats were randomly divided into three groups, i.e., the normal group, the overstrain group, and the high fat diet group, 8 in each group. After successful modeling, one piece of tissues such as spleen, kidney, liver, lung, stomach, small intestine, and large intestine was taken from each rat. Rats of the overstrain group were bonded by specially made bondage cylinder, 3 h each time on odd days, and forced to swim in cold water (10 +/- 1) degrees C for 7 min on even days alternatively for twelve weeks. Rats in the model group and the normal group were fed with standard routine granular forage for 12 weeks. Rats in the high fat diet group were fed with high fat forage for twelve weeks. All rats drank and ate freely. The mRNA and protein expressions of oatp2b1 were detected in the seven tissues using RT-PCR and Western blot.</p><p><b>RESULTS</b>The mRNA expression of oatp2b1 in liver and kidney tissues of rats in the high fat diet group was higher when compared with that of the normal group and the overstrain group (P < 0.01, P < 0.05). The oatp2b1 mRNA expression in the normal group was sequenced from high to low as liver > lung > spleen > larger intestine > small intestine > kidney > stomach. The oatp2b1 mRNA expression in the overstrain group was sequenced from high to low as liver > lung > larger intestine > spleen > kidney > stomach > small intestine. The oatp2b1 mRNA expression in the high fat diet group was sequenced from high to low as liver > lung > spleen > small intestine > kidney > larger intestine > stomach. The oatp2b1 protein expression in the lung tissue was sequenced from high to low as the overstrain group > the normal group > the high fat diet group (P > 0.05). The oatp2b1 protein expression in the spleen tissue was sequenced from high to low as the high fat diet group > the normal group > the overstrain group (P > 0.05). The oatp2b1 protein expression in the kidney tissue was sequenced from high to low as the normal group > the overstrain group > the high fat diet group (P > 0.05). The oatp2b1 protein expression in the liver tissue was sequenced from high to low as the normal group > the high fat diet group > the overstrain group (P > 0.05). Of them, the oatp2b1 protein expressed extremely less in the stomach, large intestine, and small intestine. The oatp2b1 protein expression in the normal group was sequenced from high to low as lung >spleen > liver, kidney > stomach, larger intestine, and small intestine. The oatp2b1 protein expression in the overstrain group was sequenced from high to low as lung > spleen > kidney > liver > stomach, larger intestine, and small intestine. The oatp2b1 protein expression in the high fat diet group was sequenced from high to low as spleen > lung > kidney > liver > stomach, larger intestine, and small intestine. However, there was no statistical significance among the three groups by pair-wise comparison (P > 0.05).</p><p><b>CONCLUSIONS</b>Kidney and liver might play important roles in the transportation and transformation of damp under the state of Pi deficiency syndrome. Oatp2b1 may be one of the material bases involved in the transportation and transformation of damp turbidity. Pi's function of governing transportation and transformation of damp might not only include the functions of the gastrointestinal tract, but also include partial liver and kidney functions.</p>