On the morning of May 22, Dr.Cong Huiquan, international project leader under the French Health Ministry’s Medical Service, led a delegation from Montpellier University Hospital on a visit to Chengdu. During the visi...On the morning of May 22, Dr.Cong Huiquan, international project leader under the French Health Ministry’s Medical Service, led a delegation from Montpellier University Hospital on a visit to Chengdu. During the visit, the cooperation MOU was renewed with the展开更多
Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2...Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)e- thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-,β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the eco- toxicological potential, and to distinguish previous and current inputs in agricultural soils from the Taihu Lake region. Gas chromatography equipped with a 63Ni electron-capture detector (GC-ECD) system was employed. Thirteen OCPs were detectable in all soil samples, with DDTs being the main residues, and HCHs had the second highest level of OCP residues. Although OCP residual levels were lower than those in 1990s, the residual levels for most of the DDTs and some of HCHs were still higher than the national environmental standards for agricultural soils. The ratios of DDT/DDE and γ-/α-HCH in twelve soils indicated that new inputs could be present in the soils. Thus, efforts should be made to completely ban the production of OCPs and their use in agriculture so as to reduce the threat of OCPs to food quality and human health.展开更多
Glycidyl methaerylate (GMA) is a recently recognized chemical mutagen. In order to explore the mutagenicity and mutagenic process of GMA, plasmid pBR322 was used for in vitro binding, mutant screening, and restriction...Glycidyl methaerylate (GMA) is a recently recognized chemical mutagen. In order to explore the mutagenicity and mutagenic process of GMA, plasmid pBR322 was used for in vitro binding, mutant screening, and restriction enzyme mapping. The binding between GMA and DNA in vitro has been verified by means of a spectrophotometric method. When pBR322 and GMAbound pBR322 were used to transform Eschenchia coli HB101, the following results were obtained: (1) The transformation efficiency of GMA-bound pBR322 was much lower than that of pBR322 alone. (2) GMA-bound pBR322 induced phenotype changes in competent cells (i.e., tetracycline-resistance inactivation or ampicillin-resistance inactivation). There were two mutants of pBR322, Ap~RTc~S and Ap~STc~R, in the transformants and a deductive mutant Ap~STc~S in the nontranstormants. (3) All of the selected mutants were stable and heritable. (4) When restriction enzyme maps were used to analyze the mutant Ap~RTc~S, four of seven maps were changed. some sites were shifted to other resistant gene regions, for example, sites of Bgll, EcoRl, Ilindlll. Hinclll, etc., and there was a new recognition site for Hindi (252). We did not observe any DNA fragment insertion or deletion on any maps. Our results suggest that when GMA is covalently linked to the plasmid DNA, it gives rise to a premutagenic lesion of DNA that is converted in vivo into a point mutation. (C)1990 Academic Press, Inc.展开更多
Rural finance is an issue concerned with rural people, improving rural financial management is important to close the relations of cadres and masses, maintain rural stability, and promote rural economic development. T...Rural finance is an issue concerned with rural people, improving rural financial management is important to close the relations of cadres and masses, maintain rural stability, and promote rural economic development. This article explained the main problems of village financial, the needs of introducing commission and agent system of ＂village-level accounting＂ for building a new socialist countryside, and the measures of improving commission and agent system of ＂village-level accounting＂.展开更多
文摘On the morning of May 22, Dr.Cong Huiquan, international project leader under the French Health Ministry’s Medical Service, led a delegation from Montpellier University Hospital on a visit to Chengdu. During the visit, the cooperation MOU was renewed with the
基金1Project supported by the National Key Basic Research Support Foundation (NKBRSF) of China (No. 2002CB410805)and the Outstanding Youth Fund of National Natural Science Foundation of China (No. 40325001).
文摘Selected persistent organochlorine pesticides (OCPs), including 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its principal metabolites 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis(p-chlorophenyl)e- thane (DDD), hexachlorocyclohexane (HCH) and its isomers (α-,β-, γ-, and δ-HCH), hexachlorobenzene (HCB), endo- sulfan, dieldrin, and endrin were quantified to determine current levels of organochlorine pesticides, to assess the eco- toxicological potential, and to distinguish previous and current inputs in agricultural soils from the Taihu Lake region. Gas chromatography equipped with a 63Ni electron-capture detector (GC-ECD) system was employed. Thirteen OCPs were detectable in all soil samples, with DDTs being the main residues, and HCHs had the second highest level of OCP residues. Although OCP residual levels were lower than those in 1990s, the residual levels for most of the DDTs and some of HCHs were still higher than the national environmental standards for agricultural soils. The ratios of DDT/DDE and γ-/α-HCH in twelve soils indicated that new inputs could be present in the soils. Thus, efforts should be made to completely ban the production of OCPs and their use in agriculture so as to reduce the threat of OCPs to food quality and human health.
文摘Glycidyl methaerylate (GMA) is a recently recognized chemical mutagen. In order to explore the mutagenicity and mutagenic process of GMA, plasmid pBR322 was used for in vitro binding, mutant screening, and restriction enzyme mapping. The binding between GMA and DNA in vitro has been verified by means of a spectrophotometric method. When pBR322 and GMAbound pBR322 were used to transform Eschenchia coli HB101, the following results were obtained: (1) The transformation efficiency of GMA-bound pBR322 was much lower than that of pBR322 alone. (2) GMA-bound pBR322 induced phenotype changes in competent cells (i.e., tetracycline-resistance inactivation or ampicillin-resistance inactivation). There were two mutants of pBR322, Ap~RTc~S and Ap~STc~R, in the transformants and a deductive mutant Ap~STc~S in the nontranstormants. (3) All of the selected mutants were stable and heritable. (4) When restriction enzyme maps were used to analyze the mutant Ap~RTc~S, four of seven maps were changed. some sites were shifted to other resistant gene regions, for example, sites of Bgll, EcoRl, Ilindlll. Hinclll, etc., and there was a new recognition site for Hindi (252). We did not observe any DNA fragment insertion or deletion on any maps. Our results suggest that when GMA is covalently linked to the plasmid DNA, it gives rise to a premutagenic lesion of DNA that is converted in vivo into a point mutation. (C)1990 Academic Press, Inc.
基金The Stage Achievement of the Item "Theory and Policy Research on Building A New Socialist Countryside"in Heilongjiang Philosophy and Social Service Research Base (Economic of Agricultural and Rural Area) (05zd001)
文摘Rural finance is an issue concerned with rural people, improving rural financial management is important to close the relations of cadres and masses, maintain rural stability, and promote rural economic development. This article explained the main problems of village financial, the needs of introducing commission and agent system of ＂village-level accounting＂ for building a new socialist countryside, and the measures of improving commission and agent system of ＂village-level accounting＂.
