A water extract of Artemisia capillaris Thunberg (Compositae) was investigated for protective effects against oxidative stress induced by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) in Sprague-Dawley male rats. Rats were orally administered A. capillaris water extract (ACWE; 7.5 g/kg) for 7 days before AAPH treatment (60 mg/kg). AAPH intoxication significantly elevated enzyme markers of liver injury (glutamic oxaloacetic transaminase and glutamic pyruvic transaminase). The pre-administration of ACWE significantly reduced the liver-damaging effects of AAPH as indicated by the low levels of these enzymes. Moreover, the ACWE administration significantly attenuated the accumulation of thiobarbituric acid-reactive substances in both plasma and liver tissues compared with those of rats administered AAPH alone. Furthermore, ACWE administration slightly improved the liver reduced glutathione levels and enhanced the production of antioxidant enzymes like catalase. A. capillaris contained 10.1 mg of catechin in 100 g of dried sample; the high-performance liquid chromatography results showed catechin composition in the ACWE to be 28% (-)-epigallocatechin gallate, 49% (-)- epigallocatechin, and 23% other catechins. These observations clearly indicate that ACWE contains antioxidant catechins capable of ameliorating the AAPH-induced hepatic injury by virtue of its antioxidant activity.
The steroid hormone 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) regulates cell proliferation and differentiation. Intracellular calcium (Cai) concentrations play a crucial role in these events. From our previous studies, we have demonstrated a calcium receptor (CaR) in keratinocytes which appears to regulate the initial release of Cai from intracellular stores in response to extracellular calcium (Cao) and so is likely to participate in the differentiation process. In this study, we determined whether the ability of 1,25(OH)2D3 to enhance Ca++ -induced differentiation was mediated at least in part through changes in the CaR. Keratinocytes were grown in keratinocyte growth medium (KGM) with 0.03 mM, 0.1 mM, or 1.2 mM Ca and treated with 10(-8) M 1,25(OH)2D3 till harvest after 5, 7, 14, and 21 days. CaR mRNA levels were quantitated by polymerase chain reaction. The results were compared to the ability of 1,25(OH)2D3 to enhance calcium-stimulated increases in Cai. In cells grown in 0.03 mM Ca, the CaR mRNA levels decreased with time. 1,25(OH)2D3 stimulated the levels at 5 days and prevented the falloff over the subsequent 16 days. On the other hand, in cells grown in 0.1 or 1.2 mM Ca, the message levels remained high, and 1,25(OH)2D3 had no further effect. To study the functional relationship, we harvested cells after 5 and 7 days in culture following a 24 h treatment with 1,25(OH)2D3 or vehicle to measure the Cai response to 2 mM Cao. The preconfluent cells grown in 0.03 mM Ca showed a nearly twofold increase in the Cai response to Cao when pretreated with 1,25(OH)2D3, whereas the confluent cells and those grown in 1.2 mM Ca showed no enhancement by 1,25(OH)2D3. Studies with 45Ca influx into keratinocytes revealed that 1,25(OH)2D3 enhanced the influx in preconfluent and confluent cells when grown in KGM containing 0.03 mM Ca but not in cells grown in 1.2 mM calcium. We conclude that 1,25(OH)2D3 maintains the CaR mRNA levels in cells grown in 0.03 mM Ca, thus maintaining their responsiveness to Cao and so ensuring their ability to differentiate in response to the calcium signal.
Nitrate contamination in ground and surface water is an increasingly serious environmental problem and only a few bacterial strains have been identified that have the ability to remove nitrogen pollutants from wastewater under thermophilic conditions. We therefore isolated thermophilic facultative bacterial strains from wood chips that had been composted with swine manure under aerated high temperature conditions so as to identify strains with denitrifying ability. Nine different colonies were screened and 3 long rod-shaped bacterial strains designated as SG-01, SG-02, and SG-03 were selected. The strain SG-01 could be differentiated from SG-02 and SG-03 on the basis of the method that it used for sugar utilization. The 16S rRNA genes of this strain also had high sequence similarity with Geobacillus thermodenitrificans 465T (99.6%). The optimal growth temperatures (55°C), pH values (pH 7.0), and NaCl concentrations (1%) required for the growth of strain SG-01 were established. This strain reduced 1.18 mM nitrate and 1.45 mM nitrite in LB broth after 48 h of incubation. These results suggest that the G. thermodenitrificans SG-01 strain may be useful in the removal of nitrates and nitrites from wastewater generated as a result of livestock farming.
Ca2+ regulates keratinocyte differentiation by increasing intracellular Ca2+ levels. Ca(2+)-ATPase in the Ca(2+)-induced differentiation of human keratinocytes was investigated by measuring Ca(2+)-ATPase mRNA, protein, and activity levels. Human keratinocytes were grown in Keratinocyte Growth Medium containing 0.03, 0.1, or 1.2 mM Ca2+ and assayed on days 2, 5, 7, 14, and 21. Ca(2+)-ATPase mRNA levels were found to be modestly increased in 5-, 7-, and 14-day cultured cells as compared with 2-day cultured cells, but levels fell below that of the 2-day cultured cells in the 21-day cultured cells. The Ca(2+)-ATPase mRNA levels were not affected by Ca2+ levels. A 135-kDa protein in human keratinocytes cross reacted with the monoclonal antibody against human erythrocyte Ca(2+)-ATPase. The level of this protein was decreased by Ca2+ and lost during differentiation, in parallel with the loss of enzymatic activity. Ca2+ influx of postconfluent 1.2 mM Ca(2+)-grown cells was higher than that of cells grown in lower Ca2+ concentrations. Ca2+ efflux from postconfluent cells grown in 0.03 mM Ca2+ was less than that from cells grown in stronger Ca2+ concentrations. These results suggest that the loss of the plasma membrane Ca(2+)-ATPase with time in culture contributes to the rise in intracellular Ca2+, thus promoting keratinocyte differentiation.
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