This study aimed to explore the protective effect and potential mechanism of Nostoc commune Vauch.polysaccharide(NCVP)on lead(Pb)-poisoning mice.NCVP improved Pb-induced hepatorenal toxicity and inflammatory responses...This study aimed to explore the protective effect and potential mechanism of Nostoc commune Vauch.polysaccharide(NCVP)on lead(Pb)-poisoning mice.NCVP improved Pb-induced hepatorenal toxicity and inflammatory responses and modulated key indicators of antioxidant capacity.Moreover,the down-regulation of critical proteins of the Nrf2 pathway induced by Pb could be reversed after NCVP intervention.In addition,NCVP maintained the diversity of gut bacteriobiota and restored the relative abundance of f_Prevotellaceae,g_Alloprevotella,and f_Eubacterium_coprostanoligenes_group reduced by Pb.Also,NCVP regulated the diversity and abundance of gut mycobiota affected by Pb.Specifically,Pb decreased the proportion of pathogenic species(g_Fusarium,p_Basidiomycota,g_Alternaria,g_Aspergillus,and g_Candida)while NCVP increased the abundance of probiotics species(g_Kazachstania and p_Ascomycota).Furthermore,the metabolomic analysis found that NCVP significantly altered a range of microbial metabolites,including porphobilinogen,cromakalim,salidroside,and trichostatin A,which has significant associations with specific gut bacteriobiota or mycobiota.These altered metabolites are involved in primary bile acid biosynthesis,metabolism of xenobiotics by cytochrome P450,lysine degradation,and other metabolic pathways.Overall,our findings indicate that NCVP might be an excellent natural product for eliminating Pb-induced hepatorenal toxicity,possibly by regulating gut bacteriome,mycobiome and metabolome.展开更多
Nostoc flagelliforme Born. et Flah is highly adapted to drought stress, cold and light stresses, and suitable for growing in the unfavorable areas. This paper presents the results of the analysis of the membrane (ma...Nostoc flagelliforme Born. et Flah is highly adapted to drought stress, cold and light stresses, and suitable for growing in the unfavorable areas. This paper presents the results of the analysis of the membrane (mainly thylakoid membrane) lipids from N. flagelliforme in order to investigate the relationship between membrane lipid composition and stress resistance to this cyanobacteria. The membrane lipids are composed of monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), sulfoquinovosyl diacylglycerol (SQDG) and phosphatidylglycerol (PG). The major fatty acids in these lipids are palmitic (16∶0), palmitoleic (16∶1), stearic (18∶0), oleic (18∶1), linoleic (18∶2) and linolenic (18∶3) acids. In N. flagelliforme , polyunsaturated fatty acids account for 73% of the total fatty acids, much higher than that of the other cyanobacteria reported so far. Among which 16∶1 and 18∶3 are as high as 28.9% and 34.3% respectively. The high resistance of N. flagelliforme to abnormal conditions may be associated with the extent of unsaturation of fatty acids. In addition, the wild N. flagelliforme treated with water for 30 min and cultured for 24 h and the lipid and fatty acid composition were found to be not affected by water_absorption.展开更多
The ultrastructure of the vegetative cells of Nostoc flagelliforme Born. et Flah. was investigated with high pressure freezing and freeze substitution technique and compared with the results obtained by using conv...The ultrastructure of the vegetative cells of Nostoc flagelliforme Born. et Flah. was investigated with high pressure freezing and freeze substitution technique and compared with the results obtained by using conventional preparation methods. During the processes of chemical fixation, dehydration and embedding, the cell structures might be more artificially modified than that obtained from high pressure freezing and freeze substitution. With the present method, the sheath of N. flagelliforme could be well penetrated and no extra big space could exist between the cell and the sheath. The cell protoplasm rarely shrinked. Some fine structures of cell inclusions and unit membranes became visualized. Many bacteria were harbored in the sheath. In addition, the presence of big vacuoles in the cell of N. flagelliforme as well as the presence of bacteria in the sheath shown in the present preparation for cyanobacteria has not been described so far in the literature.展开更多
[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild an...[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.展开更多
The effects of La(NO3)(3) on the liquid culture and the contents of amino acids of Nostoc commune flagelliforme cells were studied. It is indicated from the experimental results that the growth of Nostoc commune flage...The effects of La(NO3)(3) on the liquid culture and the contents of amino acids of Nostoc commune flagelliforme cells were studied. It is indicated from the experimental results that the growth of Nostoc commune flagelliforme cells can be stimulated by La(NO3)(3) at the concentrations from 1 to 200 mg.L-1, and among them the treatment of 100 mg.L-1 La(NO3)(3) has the largest A(670) and dry weight which increased by 64.9% and 61.1%, respectively as compared with the control, and La(NO3)(3) can also influence the contents of some kinds of amino acids in Nostoc commune flagelliforme cells. The contents of aspartic acid and glutamic acid decreased by 59.9% and 57.9%, respectively, and that of proline increased by 24.5% with the treatment of 200 mg.L-1 La(NO3)(3).展开更多
Cyanobacteria attracted much attention recently because of their secondary metaboliteswith potent biological activities and unusual structures. This paper reviews some recent studies on the iso-lation, structural, elu...Cyanobacteria attracted much attention recently because of their secondary metaboliteswith potent biological activities and unusual structures. This paper reviews some recent studies on the iso-lation, structural, elucidation and biological activities of the bioactive compounds from cyanobacteriaNostoc species.展开更多
The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than...The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than that of colonies. It showed that the ratios of phycocyain （PC）, allophycocyain （APC） and phycoerythrocyanin （PEC） in hormogonia and colonies were different. The room temperature chlorophyll fluorescence, 77 K chlorophyll fluorescence, measurements of PSⅠand PS Ⅱ activities all showed that colony has higher photosynthetic competence than hormogonia. Hormogonia had a higher respiration rate than colony, while their maximum photosynthetic oxygen evolution rates were very close. The responses of hormogonia and colonies to high light illuminations also were different. Both of their oxygen evolution rates decreased quickly with the prolonged high light illumination, but hormogonia can keep relatively higher PSⅡ activity （Fv/Fm） than that of colonies. The results suggested that colony was photosynthetically more competent than hormogonia, while the ability of hormogonia to tolerate high light illumination was higher than that of colony.展开更多
Using Nostoc commune as experiment target,the effect of CO 2 with different concentrations in atmosphere and dosage of UV-B on photosynthetic pigment chlorophyll a （Chl a）,carotenoids,phycoerythrin,phycocyanin,allop...Using Nostoc commune as experiment target,the effect of CO 2 with different concentrations in atmosphere and dosage of UV-B on photosynthetic pigment chlorophyll a （Chl a）,carotenoids,phycoerythrin,phycocyanin,allophycocyanin and UV-B masking materials was studied.The results showed that high dosage of UV-B radiation inhibited the synthesis process of Chl a,phycoerythrin,phycocyanin and allophycocyanin,but promoted the synthesis of carotenoids,MAAs and scytonemin,thus the negative effect produced by UV-B radiation was reduced and the resistance of Nostoc commune against UV-B radiation was enhanced.展开更多
The detailed mechanisms that facilitate the heat tolerance of terrestrial cyanobacteria have not been completely elucidated, although several reports have revealed aspects of the heat tolerance mechanisms of several o...The detailed mechanisms that facilitate the heat tolerance of terrestrial cyanobacteria have not been completely elucidated, although several reports have revealed aspects of the heat tolerance mechanisms of several other organisms. The dormant cells, called akinetes, of the terrestrial cyanobacterium Nostoc sp. HK-01 can revive after dry heat exposure at 100℃ for more than 10 h. We investigated the compatible solutes that protect the biomolecules in Nostoc sp. HK-01 akinetes using colonies containing various proportions of akinetes. We extracted the intracellular substances from each colony with 80% ethanol, which we purified with a series of analytical columns and analyzed by high-performance liquid chromatography and liquid chromatography-electrospray ionization-mass spectrometry. The compatible solutes were screened for their ability to prevent protein aggregation upon heating using the model enzyme lactate dehydrogenase. We detected an accumulation of glucosylglycerol, betaine, and glycine in akinetes. In addition, we confirmed that betaine, glycine, sucrose, and trehalose contributed to the prevention of the protein aggregation. The levels of sucrose and glycine in the colonies were approximately 1000× higher than those of glucosylglycerol, betaine, or trehalose. Our results indicated that sucrose and glycine are the main compatible solutes in the hydrophilic fractions of the cell extracts of Nostoc sp. HK-01 akinetes.展开更多
Vitamin B12 contents in the edible cyanobacterium Nostoc flagelliforme, also known as hair vegetable, were assayed using a microbiological method. We detected high vitamin B12 contents in samples of naturally grown ce...Vitamin B12 contents in the edible cyanobacterium Nostoc flagelliforme, also known as hair vegetable, were assayed using a microbiological method. We detected high vitamin B12 contents in samples of naturally grown cells (109.2 ± 18.5 μg/100g dry weight) and cultured cells (120.2 ± 53.6 μg/100g dry weight). However, commercially available hair vegetable samples, which comprised fake substitutes and Nostoc, had variable contents (4.8 - 101.6 μg/100g dry weight) because concomitant fake items contain very low vitamin B12 contents. To evaluate whether natural and cultured N. flagelliforme samples contained vitamin B12 or pseudovitamin B12, corrinoid compounds were purified and identified as pseudovitamin B12 (approximately 72%) and vitamin B12 (approximately 28%) using silica gel 60 TLC bioautography and LC/MS. The results suggested that N. flagelliforme contains substantial amounts of pseudovitamin B12, which is inactive in humans.展开更多
The combined use of morphological identification and phylogenetic characterization employing primers that target the 16S rDNA region led to the identification of ten isolates belonging to eight cyanobacterial genera i...The combined use of morphological identification and phylogenetic characterization employing primers that target the 16S rDNA region led to the identification of ten isolates belonging to eight cyanobacterial genera in the Nile River. 16S-23S ITS region was amplified to confirm two isolates to be affiliated to genus Nostoc. Using MALDI-TOF/MS, we detected the production of the hepatotoxic demethylated MC-LR by one isolate that clustered together with the genus Nostoc. Protein phosphatase inhibition assay has confirmed toxicity. Our results add to the rising importance of Nostoc as a hepatotoxin-producing cyanobacterium. Furthermore, our results stress that water municipalities in the studied region need to assess the potential threat of toxic cyanobacteria that may pose to human health and economy.展开更多
Gexianmi moisturizing lotion was prepared from Gexianmi extract, carbomer, EDTA-Na2, citric acid, glycerin, butanediol, ceramide, cetearyl alcohol, hydrogenated polydecene, shea butter, etc., and skin moisture content...Gexianmi moisturizing lotion was prepared from Gexianmi extract, carbomer, EDTA-Na2, citric acid, glycerin, butanediol, ceramide, cetearyl alcohol, hydrogenated polydecene, shea butter, etc., and skin moisture contents of different treatments were measured. The data were analyzed by variance analysis and multiple comparisons. The results showed that: Gexianmi moisturizing lotion had a better moisturizing effect, which was better than that of anthocyanin moisturizing lotion. Therefore, Gexianmi moisturizing lotion can be used to effectively maintain the moisture of the human skin stratum corneum.展开更多
To study the promoter activities of genes cpcT 2 and cpcS 2,several upstream DNA fragments of these two genes with different lengths were selected.These fragments were fused with promoterless gfp（reporter gene） for ...To study the promoter activities of genes cpcT 2 and cpcS 2,several upstream DNA fragments of these two genes with different lengths were selected.These fragments were fused with promoterless gfp（reporter gene） for constructing five recombinant plasmids.Then,these recombinant plasmids were transferred into Nostoc PCC 7120 by conjugation.The promoter activities of genes cpcT 2 and cpcS 2 were determined by observing the fluorescence of green fluorescent protein（GFP） with a fluorescence microscope.The result showed that the 1 300 bp（-1 300 to 0 bp） and 2 600 bp（-2 600 to 0 bp） upstream fragments of cpcT 2 had strong promoter activity and the promoter activity of the 680 bp（-680 to 0 bp） fragment was weaker than that of two above fragments of cpcT 2.The 2 000 bp（-2 000 to 0 bp） upstream fragment of cpcS 2 revealed weak promoter activity.This showed that a strong promoter of cpcT 2 was located in the upstream fragment between-680 and-1 300 bp.展开更多
基金supported by the Program of the National Natural Science Foundation of China(31872519)General Project of Jilin Provincial Department of Science and Technology(20230101247JC)the Open Research Fund of Engineering Research Center of Bioreactor and Pharmaceutical Development,Ministry of Education.(KF202002).
文摘This study aimed to explore the protective effect and potential mechanism of Nostoc commune Vauch.polysaccharide(NCVP)on lead(Pb)-poisoning mice.NCVP improved Pb-induced hepatorenal toxicity and inflammatory responses and modulated key indicators of antioxidant capacity.Moreover,the down-regulation of critical proteins of the Nrf2 pathway induced by Pb could be reversed after NCVP intervention.In addition,NCVP maintained the diversity of gut bacteriobiota and restored the relative abundance of f_Prevotellaceae,g_Alloprevotella,and f_Eubacterium_coprostanoligenes_group reduced by Pb.Also,NCVP regulated the diversity and abundance of gut mycobiota affected by Pb.Specifically,Pb decreased the proportion of pathogenic species(g_Fusarium,p_Basidiomycota,g_Alternaria,g_Aspergillus,and g_Candida)while NCVP increased the abundance of probiotics species(g_Kazachstania and p_Ascomycota).Furthermore,the metabolomic analysis found that NCVP significantly altered a range of microbial metabolites,including porphobilinogen,cromakalim,salidroside,and trichostatin A,which has significant associations with specific gut bacteriobiota or mycobiota.These altered metabolites are involved in primary bile acid biosynthesis,metabolism of xenobiotics by cytochrome P450,lysine degradation,and other metabolic pathways.Overall,our findings indicate that NCVP might be an excellent natural product for eliminating Pb-induced hepatorenal toxicity,possibly by regulating gut bacteriome,mycobiome and metabolome.
文摘Nostoc flagelliforme Born. et Flah is highly adapted to drought stress, cold and light stresses, and suitable for growing in the unfavorable areas. This paper presents the results of the analysis of the membrane (mainly thylakoid membrane) lipids from N. flagelliforme in order to investigate the relationship between membrane lipid composition and stress resistance to this cyanobacteria. The membrane lipids are composed of monogalactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG), sulfoquinovosyl diacylglycerol (SQDG) and phosphatidylglycerol (PG). The major fatty acids in these lipids are palmitic (16∶0), palmitoleic (16∶1), stearic (18∶0), oleic (18∶1), linoleic (18∶2) and linolenic (18∶3) acids. In N. flagelliforme , polyunsaturated fatty acids account for 73% of the total fatty acids, much higher than that of the other cyanobacteria reported so far. Among which 16∶1 and 18∶3 are as high as 28.9% and 34.3% respectively. The high resistance of N. flagelliforme to abnormal conditions may be associated with the extent of unsaturation of fatty acids. In addition, the wild N. flagelliforme treated with water for 30 min and cultured for 24 h and the lipid and fatty acid composition were found to be not affected by water_absorption.
文摘The ultrastructure of the vegetative cells of Nostoc flagelliforme Born. et Flah. was investigated with high pressure freezing and freeze substitution technique and compared with the results obtained by using conventional preparation methods. During the processes of chemical fixation, dehydration and embedding, the cell structures might be more artificially modified than that obtained from high pressure freezing and freeze substitution. With the present method, the sheath of N. flagelliforme could be well penetrated and no extra big space could exist between the cell and the sheath. The cell protoplasm rarely shrinked. Some fine structures of cell inclusions and unit membranes became visualized. Many bacteria were harbored in the sheath. In addition, the presence of big vacuoles in the cell of N. flagelliforme as well as the presence of bacteria in the sheath shown in the present preparation for cyanobacteria has not been described so far in the literature.
文摘[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.
文摘The effects of La(NO3)(3) on the liquid culture and the contents of amino acids of Nostoc commune flagelliforme cells were studied. It is indicated from the experimental results that the growth of Nostoc commune flagelliforme cells can be stimulated by La(NO3)(3) at the concentrations from 1 to 200 mg.L-1, and among them the treatment of 100 mg.L-1 La(NO3)(3) has the largest A(670) and dry weight which increased by 64.9% and 61.1%, respectively as compared with the control, and La(NO3)(3) can also influence the contents of some kinds of amino acids in Nostoc commune flagelliforme cells. The contents of aspartic acid and glutamic acid decreased by 59.9% and 57.9%, respectively, and that of proline increased by 24.5% with the treatment of 200 mg.L-1 La(NO3)(3).
文摘Cyanobacteria attracted much attention recently because of their secondary metaboliteswith potent biological activities and unusual structures. This paper reviews some recent studies on the iso-lation, structural, elucidation and biological activities of the bioactive compounds from cyanobacteriaNostoc species.
文摘The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than that of colonies. It showed that the ratios of phycocyain （PC）, allophycocyain （APC） and phycoerythrocyanin （PEC） in hormogonia and colonies were different. The room temperature chlorophyll fluorescence, 77 K chlorophyll fluorescence, measurements of PSⅠand PS Ⅱ activities all showed that colony has higher photosynthetic competence than hormogonia. Hormogonia had a higher respiration rate than colony, while their maximum photosynthetic oxygen evolution rates were very close. The responses of hormogonia and colonies to high light illuminations also were different. Both of their oxygen evolution rates decreased quickly with the prolonged high light illumination, but hormogonia can keep relatively higher PSⅡ activity （Fv/Fm） than that of colonies. The results suggested that colony was photosynthetically more competent than hormogonia, while the ability of hormogonia to tolerate high light illumination was higher than that of colony.
基金Supported by the National Natural Science Foundation of China(30700084)
文摘Using Nostoc commune as experiment target,the effect of CO 2 with different concentrations in atmosphere and dosage of UV-B on photosynthetic pigment chlorophyll a （Chl a）,carotenoids,phycoerythrin,phycocyanin,allophycocyanin and UV-B masking materials was studied.The results showed that high dosage of UV-B radiation inhibited the synthesis process of Chl a,phycoerythrin,phycocyanin and allophycocyanin,but promoted the synthesis of carotenoids,MAAs and scytonemin,thus the negative effect produced by UV-B radiation was reduced and the resistance of Nostoc commune against UV-B radiation was enhanced.
文摘The detailed mechanisms that facilitate the heat tolerance of terrestrial cyanobacteria have not been completely elucidated, although several reports have revealed aspects of the heat tolerance mechanisms of several other organisms. The dormant cells, called akinetes, of the terrestrial cyanobacterium Nostoc sp. HK-01 can revive after dry heat exposure at 100℃ for more than 10 h. We investigated the compatible solutes that protect the biomolecules in Nostoc sp. HK-01 akinetes using colonies containing various proportions of akinetes. We extracted the intracellular substances from each colony with 80% ethanol, which we purified with a series of analytical columns and analyzed by high-performance liquid chromatography and liquid chromatography-electrospray ionization-mass spectrometry. The compatible solutes were screened for their ability to prevent protein aggregation upon heating using the model enzyme lactate dehydrogenase. We detected an accumulation of glucosylglycerol, betaine, and glycine in akinetes. In addition, we confirmed that betaine, glycine, sucrose, and trehalose contributed to the prevention of the protein aggregation. The levels of sucrose and glycine in the colonies were approximately 1000× higher than those of glucosylglycerol, betaine, or trehalose. Our results indicated that sucrose and glycine are the main compatible solutes in the hydrophilic fractions of the cell extracts of Nostoc sp. HK-01 akinetes.
文摘Vitamin B12 contents in the edible cyanobacterium Nostoc flagelliforme, also known as hair vegetable, were assayed using a microbiological method. We detected high vitamin B12 contents in samples of naturally grown cells (109.2 ± 18.5 μg/100g dry weight) and cultured cells (120.2 ± 53.6 μg/100g dry weight). However, commercially available hair vegetable samples, which comprised fake substitutes and Nostoc, had variable contents (4.8 - 101.6 μg/100g dry weight) because concomitant fake items contain very low vitamin B12 contents. To evaluate whether natural and cultured N. flagelliforme samples contained vitamin B12 or pseudovitamin B12, corrinoid compounds were purified and identified as pseudovitamin B12 (approximately 72%) and vitamin B12 (approximately 28%) using silica gel 60 TLC bioautography and LC/MS. The results suggested that N. flagelliforme contains substantial amounts of pseudovitamin B12, which is inactive in humans.
文摘The combined use of morphological identification and phylogenetic characterization employing primers that target the 16S rDNA region led to the identification of ten isolates belonging to eight cyanobacterial genera in the Nile River. 16S-23S ITS region was amplified to confirm two isolates to be affiliated to genus Nostoc. Using MALDI-TOF/MS, we detected the production of the hepatotoxic demethylated MC-LR by one isolate that clustered together with the genus Nostoc. Protein phosphatase inhibition assay has confirmed toxicity. Our results add to the rising importance of Nostoc as a hepatotoxin-producing cyanobacterium. Furthermore, our results stress that water municipalities in the studied region need to assess the potential threat of toxic cyanobacteria that may pose to human health and economy.
文摘Gexianmi moisturizing lotion was prepared from Gexianmi extract, carbomer, EDTA-Na2, citric acid, glycerin, butanediol, ceramide, cetearyl alcohol, hydrogenated polydecene, shea butter, etc., and skin moisture contents of different treatments were measured. The data were analyzed by variance analysis and multiple comparisons. The results showed that: Gexianmi moisturizing lotion had a better moisturizing effect, which was better than that of anthocyanin moisturizing lotion. Therefore, Gexianmi moisturizing lotion can be used to effectively maintain the moisture of the human skin stratum corneum.
基金Supported by the National Natural Science Foundation of China(30870541, 31070743)China Postdoctoral Science Foundation (20100471191)
文摘To study the promoter activities of genes cpcT 2 and cpcS 2,several upstream DNA fragments of these two genes with different lengths were selected.These fragments were fused with promoterless gfp（reporter gene） for constructing five recombinant plasmids.Then,these recombinant plasmids were transferred into Nostoc PCC 7120 by conjugation.The promoter activities of genes cpcT 2 and cpcS 2 were determined by observing the fluorescence of green fluorescent protein（GFP） with a fluorescence microscope.The result showed that the 1 300 bp（-1 300 to 0 bp） and 2 600 bp（-2 600 to 0 bp） upstream fragments of cpcT 2 had strong promoter activity and the promoter activity of the 680 bp（-680 to 0 bp） fragment was weaker than that of two above fragments of cpcT 2.The 2 000 bp（-2 000 to 0 bp） upstream fragment of cpcS 2 revealed weak promoter activity.This showed that a strong promoter of cpcT 2 was located in the upstream fragment between-680 and-1 300 bp.
