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Antibiotics and bile salts have been used to differentiate between heterotrophic activity of halophilic Archaea and Bacteria in saltern ponds. In NaCl-saturated brines of crystallizer ponds, most activity was attributed to Archaea. Following the recent isolation of Haloquadratum, the dominant archaeon in the salterns (reported to be sensitive to chloramphenicol and erythromycin), and the discovery of Salinibacter, a representative of the Bacteria, in the same ecosystem, reevaluation of the earlier data is required. The authors measured amino acid incorporation by Haloquadratum and Salinibacter suspended in crystallizer brine to investigate the suitability of antibiotics and bile salts to distinguish between archaeal and bacterial activities. The amino acid uptake rate per cell in Salinibacter was two orders of magnitude lower than that of Haloquadratum under the same conditions. Salinibacter was inhibited by chloramphenicol, erythromycin, and deoxycholate, but not by taurocholate. Erythromycin did not inhibit incorporation by Haloquadratum, but moderate inhibition was found by chloramphenicol at 10-50 microg mL(-1). Deoxycholate was highly inhibitory, but only partial inhibition was obtained in the presence of 25 microg mL(-1) taurocholate. Inhibition by chloramphenicol and taurocholate increased with increasing salt concentration. Erythromycin and taurocholate proved most valuable to differentiate between archaeal and bacterial activities in saltern brines.

A total of forty-five halophilous microorganisms were isolated from the sediment of saline lake in Qinghai Province, among which, filamentous fungus F16 showed the highest activity of anti-microorganism and anti-tumor. The ethyl acetate extract of F16 culture filtrate showed a strong cytotoxicity, and could inhibit the growth of four kinds of bacteria, especially Escherichia coli. When the concentration of the crude extract was 50 microg x ml(-1), the inhibition rate to liver cancer cell BEL7402 reached 76. 91%. The optimal temperature for F16 growth was 15 degrees C , and the increase of salt concentration in media would inhibit its growth. When the concentration of salt surpassed 15% , F16 could not survive. F16 grew well when the pH value ranged from 5 to 9.