Microcalorimetric bioassay for acute cellular toxicity is based on metabolicheat production from cultured cells. The biological response to toxicants is the inhibition of theheat production rate in cells, and toxicity...Microcalorimetric bioassay for acute cellular toxicity is based on metabolicheat production from cultured cells. The biological response to toxicants is the inhibition of theheat production rate in cells, and toxicity is expressed as the concentration of toxicant that is50% effective to this inhibition (IC_(50)). In this paper, the effect of Na_2SeO_3 on Bacillussubtilis growth was investigated at 37℃ by microcalorimetry. The relationship between growth rateconstants (k) and concentration of Na_2SeO_3(c) shows a logarithmic normal distribution, and IC_(50)is 20.3 μg/mL. All these thermokinetic information is readily obtained by an LKB 2277-204 heatconduction microcalorimeter. Microcalorimetry is a quantitative, inexpensive, and versatile methodfor toxicology research.展开更多
Removal of Pb^（2＋）and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb^（2＋）and organophosphorus still remains largely unexplored. Bacillus s...Removal of Pb^（2＋）and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb^（2＋）and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb^（2＋）and biodegradation of acephate. In the present study, both Pb^（2＋）and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions.Batch experiments were conducted to study the influence of p H, interaction time and Pb^（2＋）concentration on the process of removal of Pb2＋. At the temperature of 25°C, the maximum removal of Pb^（2＋）by B. subtilis FZUL-33 was 381.31 ± 11.46 mg/g under the conditions of p H 5.5, initial Pb^（2＋）concentration of 1300 mg/L, and contact time of 10 min. Batch experiments were conducted to study the influence of acephate on removal of Pb^（2＋）and the influence of Pb2＋on biodegradation of acephate by B. subtilis FZUL-33. In the mixed system of acephate–Pb2＋, the results show that biodegradation of acephate by B. subtilis FZUL-33 released PO43＋, which promotes mineralization of Pb2＋. The process of biodegradation of acephate was affected slightly when the concentration of Pb2＋was below 100 mg/L. Based on the results, it can be inferred that the B. subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination.展开更多
文摘为研制生物农药新剂型,利用喷雾干燥法制备浓缩枯草芽孢杆菌BSD-2菌粉。以集粉率和抑菌活性为指标,确定最佳喷雾干燥工艺条件。在发酵液中加入15%β-环糊精作为填料,最佳入口温度为170℃,料液温度为30℃,热风量为20 m3/h,入料流量为15 m L/min。此条件下喷雾集粉率达到25.4%,效价保留率为66%,BSD-2菌体存活率为75%。
文摘Microcalorimetric bioassay for acute cellular toxicity is based on metabolicheat production from cultured cells. The biological response to toxicants is the inhibition of theheat production rate in cells, and toxicity is expressed as the concentration of toxicant that is50% effective to this inhibition (IC_(50)). In this paper, the effect of Na_2SeO_3 on Bacillussubtilis growth was investigated at 37℃ by microcalorimetry. The relationship between growth rateconstants (k) and concentration of Na_2SeO_3(c) shows a logarithmic normal distribution, and IC_(50)is 20.3 μg/mL. All these thermokinetic information is readily obtained by an LKB 2277-204 heatconduction microcalorimeter. Microcalorimetry is a quantitative, inexpensive, and versatile methodfor toxicology research.
基金supported by the National Basic Research Program (973) of China (No. 2014CB846003)the National Natural Science Foundation of China (Nos. 41372346 21577018)
文摘Removal of Pb^（2＋）and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb^（2＋）and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb^（2＋）and biodegradation of acephate. In the present study, both Pb^（2＋）and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions.Batch experiments were conducted to study the influence of p H, interaction time and Pb^（2＋）concentration on the process of removal of Pb2＋. At the temperature of 25°C, the maximum removal of Pb^（2＋）by B. subtilis FZUL-33 was 381.31 ± 11.46 mg/g under the conditions of p H 5.5, initial Pb^（2＋）concentration of 1300 mg/L, and contact time of 10 min. Batch experiments were conducted to study the influence of acephate on removal of Pb^（2＋）and the influence of Pb2＋on biodegradation of acephate by B. subtilis FZUL-33. In the mixed system of acephate–Pb2＋, the results show that biodegradation of acephate by B. subtilis FZUL-33 released PO43＋, which promotes mineralization of Pb2＋. The process of biodegradation of acephate was affected slightly when the concentration of Pb2＋was below 100 mg/L. Based on the results, it can be inferred that the B. subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination.
