Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 16 de 16
Filter
1.
Int J Biol Macromol ; 209(Pt A): 299-314, 2022 Jun 01.
Article in English | MEDLINE | ID: mdl-35381282

ABSTRACT

Antibiotic-resistant bacteria (including MRSA) in the clinic pose a growing threat to public health, and antimicrobial peptides (AMPs) have great potential as efficient treatment alternatives. Houseflies have evolved over long periods in complex, dirty environments, developing a special immune system to overcome challenges in harmful environments. AMPs are key innate immune molecules. Herein, two differentially expressed AMPs, Phormicins A and B, were identified by screening transcriptomic changes in response to microbial stimulation. Structural mimic assays indicated that these AMPs exhibited functional divergence due to their C-terminal features. Expression analysis showed that they had different expression patterns. Phormicin B had higher constitutive expression than Phormicin A. However, Phormicin B was sharply downregulated, whereas Phormicin A was highly upregulated, after microbial stimulation. The MIC, MBC and time-growth curves showed the antibacterial spectrum of these peptides. Crystal violet staining and SEM showed that Phormicin D inhibited MRSA biofilm formation. TEM suggested that Phormicin D disrupted the MRSA cell membrane. Furthermore, Phormicin D inhibited biofilm formation by downregulating the expression of biofilm-related genes, including altE and embp. Therefore, housefly Phormicins were functionally characterized as having differential expression patterns and antibacterial & antibiofilm activities. This study provides a new potential peptide for clinical MRSA therapy.


Subject(s)
Houseflies , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antimicrobial Peptides , Biofilms , Houseflies/genetics , Microbial Sensitivity Tests
2.
Ecol Evol ; 10(21): 12395-12406, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33537120

ABSTRACT

The objective of this study was to investigate the effects of grazing on midday gerbil (Meriones meridianus) population characteristics and survival of animals of different genders. The experiment used a randomized complete block design and was conducted in Alxa Left Banner, Inner Mongolia, China, in 2002 (The agricultural reclamation plots set up in 1994). From April 2006 to October 2010, midday gerbils were live-trapped in 3 light grazing plots, 3 overgrazed plots, and 3 grazing exclusion plots. The quantity of vegetation was investigated in the two different grazing intensity areas and grazing exclusion area to determine the relationship between gerbils and plant food availability. The results suggested that there was higher gerbil density, individual body mass, and daily body mass growth rate in the grazing exclusion sites than the other sites across the whole year. Females had higher survival in grazing exclusion areas than in other treatments, but the males' survival showed the opposite pattern. Our results indicated that grazing negatively influenced the midday gerbil population by reducing food availability. Grazing influenced the survival rates of male midday gerbils positively, but had negative effects on females. The reason for gendered differences in survival rates of midday gerbils requires further investigation.

3.
Huan Jing Ke Xue ; 40(8): 3633-3641, 2019 Aug 08.
Article in Chinese | MEDLINE | ID: mdl-31854770

ABSTRACT

Focusing on the removal of ammonia nitrogen from polluted water, the absorption properties of five materials (zeolite, maifanite, diatomite, bentonite, and activated carbon) were tested. Results showed that the pseudo-second-order kinetic equation was suitable for data fitting for the five materials. The maximum theoretical adsorption capacities of the five materials were 2.0673 mg·g-1, 0.9982 mg·g-1, 0.7580 mg·g-1, 1.7486 mg·g-1, and 1.0160 mg·g-1, respectively, which were close to the experimental value. Chemical-based adsorption was the main mode of adsorption. Data for diatomite were fitted using the Langmuir isotherm equation, and belonged to the single-layer molecular adsorption group, while the other four materials were fitted using the Freundlich isotherm equation, belonging to the multi-layer molecular adsorption group. Moreover, the results showed that the removal rates of ammonia nitrogen by zeolite, diatomite, bentonite, and activated carbon increased with an increase in dosage, and the maximum removal rates were 100%, 10.46%, 49.25%, and 16.87%, respectively. A maifanite dosage of 0.4g achieved the maximum removal rate of 48.85%. At pH 4-10, the adsorption capacities of zeolite and maifanite first increased and then decreased, while that of diatomite, bentonite, and activated carbon slowly increased. The desorption capacity of the five tested materials increased with an increase in the initial concentration of ammonia nitrogen.

4.
Huan Jing Ke Xue ; 40(2): 582-589, 2019 Feb 08.
Article in Chinese | MEDLINE | ID: mdl-30628320

ABSTRACT

To examine the effects of seasonal changes and precipitation on the concentrations of various nitrogen and phosphorus forms in Dianchi Lake, the concentrations of various nitrogen and phosphorus forms of atmospheric deposition were determined by UV spectrophotometry. Additionally, the contributions of nitrogen and phosphorus to water pollution in Dianchi Lake were discussed. The results showed that the atmospheric depositional nitrogen concentration in Dianchi Lake is generally consistent with the characteristics of the low rainy season and high dry season. The nitrogen and phosphorus load of atmospheric deposition was positively correlated with rainfall. Seasonal changes were mainly characterized by low dry season and high rainy season. The atmospheric depositional nitrogen load was dominated by dissolved inorganic nitrogen, which accounted for 63.70% of the total nitrogen deposition load. The phosphorus load was mainly PP, which accounted for 45.54% of the total phosphorus precipitation load. Excessive fertilization and loss of nitrogen and phosphorus from fertilizers are the major sources of nitrogen and phosphorus in atmospheric wet deposition. Combined with data from rivers entering the lake, the settlements of TN and TP in the atmospheric deposition of Dianchi Lake were 6.14% and 12.76% of the river load, respectively. Therefore, the primary source of pollution in Dianchi Lake was still the load brought by the river into the lake. However, the nitrogen and phosphorus fluxes in the atmospheric deposition of Dianchi Lake were at intermediate levels compared with other regions, so this contribution requires further investigation.

5.
Huan Jing Ke Xue ; 39(4): 1616-1627, 2018 Apr 08.
Article in Chinese | MEDLINE | ID: mdl-29964986

ABSTRACT

A comprehensive survey of the pollution characteristics of persistent organic pollutants (POPs) in the surface water and surface sediment of Baiyangdian Lake was carried out. The survey showed that:① The concentrations of the polycyclic aromatic hydrocarbons(PAHs), organic chlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) in the surface water of Baiyangdian Lake were 71.32-228.27 ng·L-1, 2.62-6.13 ng·L-1, and 0-6.5 ng·L-1, respectively, and those in the surface sediment were 163.20-861.43 ng·g-1, 2.25-6.07 ng·g-1, and 230.96-1224.13 pg·g-1, respectively. On comparison with historical data, the concentrations of PAHs and OCPs in both the surface water and surface sediment were found to be decreasing, while compared with the domestic and foreign lakes, the concentration of PBDEs in the surface sediment was at a low level. ② The main source of PAHs, both in the surface water and surface sediment in Baiyangdian Lake, originated from fuel discharge and combustion sources. HCHs compose the main part of OCPs in both the surface water (93.76%) and surface sediment (63.10%). In the surface water body, HCHs mainly originated from the degradation of industrial HCHs; in some sites HCHs originated from atmospheric long-distance transmission and the usage of Lindane, while DDTs originated from historical residues. In surface sediment, HCHs mainly originated from the usage of new Lindane, with little industrial HCHs, and DDTs mainly originated from historical residues, while new DDTs may have been used in some sites. BDE-2 (65.80%) composed the main part of PBEDs in the surface water, and it mainly originated from atmospheric long-distance transmission and degradation of high brominated diphenyl ethers; BDE-209 (63.82%) constituted the main part of PBDEs in the surface sediment, and it mainly originated from the commercial Deca-BDEs.③ Ecological Risk Assessment show that there was no obvious ecological risks in Baiyangdian Lake, but in some sites POPs may cause ecological risks; these sites should be monitored more frequently.

6.
Huan Jing Ke Xue ; 39(5): 2048-2055, 2018 May 08.
Article in Chinese | MEDLINE | ID: mdl-29965504

ABSTRACT

In order to survey the present pollution from volatile organic compounds in Baiyangdian Lake, 15 water samples were collected in March 2016, and analyzed for 54 VOCs by purge and trap gas chromatography-mass spectrometry. The distribution characteristics and health risk assessments were investigated, and the pollution from the VOCs was evaluated by a comprehensive pollution index. The survey showed that:① a total of 14 VOCs were detected in Baiyangdian water, with a 100% detection rate for dichloromethane, benzene, toluene, ethylbenzene, xylene, and 1,3,5-trimethylbenzene; xylene had the highest concentration with an average concentration of 564.9 ng ·L-1; and trichloroethylene had the lowest concentration with an average concentration of 3.3 ng ·L-1 and a detection rate of only 13.3%; ② the total concentration of VOCs in Baiyangdian water was between 423.0 and 4207.8 ng ·L-1, and benzene was the main pollutant, with its main source coming from the effluent from the upstream sewage treatment plant, the industrial wastewater, and the exhaust emissions of motor vehicles in the city; and ③the health risk assessment showed that VOCs in Baiyangdian Lake did not produce carcinogenic and non-carcinogenic risks to humans, and the VOC comprehensive pollution index shows that the VOCs in the Baiyangdian Lake were at a clean level.


Subject(s)
Lakes/chemistry , Risk Assessment , Volatile Organic Compounds/analysis , Water Pollutants, Chemical/analysis , China , Cities , Environmental Monitoring , Humans
7.
Ecol Evol ; 8(24): 12773-12779, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30619581

ABSTRACT

The Transbaikal zokor (Myospalax psilurus) is a dominant rodent distributed in the meadow steppe of Inner Mongolia in northern China. Due to long history of evolution in subterranean environment, the zokor has an adaptive behavior: sealing burrow entrances. When a burrow is damaged, exposed entrances appear, and within a relatively short time, the zokor would be active in sealing the entrances to reduce risks to its survival. In general, it is thought that zokors avoid light and wind, which is consistent with their behavior of sealing burrow entrances. However, direct evidence from field experimental research has been lacking. This study set up 68 field sampling points in a meadow steppe in Inner Mongolia from August to September, 2014 and used a wind-light isolator to study the effects of wind and light factors on zokor burrow entrance sealing behavior. The results showed that there were no significant correlations between wind or light factors and the frequency of zokor burrow entrance sealing. Therefore, wind and light factors are not direct factors associated with zokors actively sealing burrow entrances.

8.
Arch Gerontol Geriatr ; 59(2): 372-81, 2014.
Article in English | MEDLINE | ID: mdl-24852667

ABSTRACT

This study was carried out to explore the relationship between the SES, mental health and the NLTC of the Japanese elderly, with the aim of providing useful information to lower the NLTC. A longitudinal survey was carried out in Tama City, Tokyo in 2001 and 2004. Data were collected from the urban-dwelling older adults, aged 65 years old and above, through self-reported questionnaires, which was participated by 7905 respondents (47.6% male and 52.4% female). Chi-square test, Kendall tau-b correlation analysis and structural equation modeling (SEM) were used to identify the association between SES, mental health and NLTC. The results of the SEM analysis indicated that mental health would exert a negative effect on NLTC for both the elderly men and the elderly women, while the effect was stronger for the elderly women; SES was significantly and negatively associated to NLTC, both for the elderly men and elderly women; a significant and positive relationship was observed between SES and mental health for both genders, but slightly stronger for the elderly men. These findings have implications for targeting the interventions that are aimed to delaying the NLTC and the financing of LTC system.


Subject(s)
Health Services Needs and Demand , Long-Term Care/statistics & numerical data , Mental Health , Social Class , Aged , Aged, 80 and over , Female , Humans , Longitudinal Studies , Male , Surveys and Questionnaires , Tokyo , Urban Population
9.
Huan Jing Ke Xue ; 33(6): 1852-7, 2012 Jun.
Article in Chinese | MEDLINE | ID: mdl-22946165

ABSTRACT

Tissue distribution and bioconcentration factors of tetrabromobisphenol A (TBBPA) in five economic fishes in Chaohu Lake were measured with SPE-HPLC. The results showed that, the average concentration of TBBPA was 4.70-11.20 ng x g(-1) (dry weight) in these fishes, in an order as White fish > Silver Carp > Bighead Carp > Common Carp > Longsnout Catfish. The highest concentration of TBBPA was found in the kidney, followed by liver and gill. The concentrations in fat and muscle were very low. Silver carp was really different from the other four fishes with the highest measured level in liver, followed by kidney and gills. In addition, the TBBPA concentration in tissues of the white fish showed positive correlation with the fish weight, especially in liver and kidney, but the trend is not significant in the back and belly tissues. The bioaccumulation factors of TBBPA for the 5 fishes were 9.56-22.64 based on the average concentration of TBBPA in water (0.52 microg x L(-1)) detected in this study, indicating insignificant bioconcentration effects of TBBPA on five fishes in Chaohu Lake.


Subject(s)
Fishes/metabolism , Flame Retardants/metabolism , Food Contamination/analysis , Polybrominated Biphenyls/metabolism , Water Pollution, Chemical/statistics & numerical data , Animals , China , Flame Retardants/analysis , Lakes , Polybrominated Biphenyls/analysis , Tissue Distribution
10.
Environ Pollut ; 169: 59-63, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22683481

ABSTRACT

Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant. It has been detected in the environment and has shown to high toxicity to aquatic organisms. To date no aquatic life criteria for TBBPA have been proposed. This work compiled all literature toxicity data of TBBPA on Chinese aquatic species. Eight resident Chinese aquatic organisms were used in toxicity tests to supplement the existing toxicity data for TBBPA. Ten genera mean acute values and three genera mean chronic values to freshwater aquatic animals, as well as two genera toxicity values to aquatic plants were collected. A criterion maximum concentration of 0.1475 mg/L and a criterion continuous concentration of 0.0126 mg/L were derived based on these data, according to the U.S. Environmental Protection Agency guidelines. These criteria may be useful in risk assessment of TBBPA in the ambient water environment.


Subject(s)
Aquatic Organisms/drug effects , Environmental Monitoring/standards , Flame Retardants/analysis , Fresh Water/analysis , Polybrominated Biphenyls/analysis , Water Pollutants, Chemical/analysis , Animals , Aquatic Organisms/growth & development , China , Ecosystem , Flame Retardants/toxicity , Polybrominated Biphenyls/toxicity , United States , United States Environmental Protection Agency/standards , Water Pollutants, Chemical/toxicity
11.
Am J Chin Med ; 39(1): 121-34, 2011.
Article in English | MEDLINE | ID: mdl-21213403

ABSTRACT

Pancreatic cancer is a devastating disease characterized by low sensitivity to conventional chemotherapeutic treatment that has a poor prognosis. Therefore, novel effective chemotherapeutic regimens need to be developed. In this study, we analyzed the combined cytotoxic effect of triptolide and hydroxycamptothecin (HCPT) on pancreatic cancer cell line PANC-1 by using 3-(4.5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) and fluorescence- activated cell sorting (FACS) assays. Our results showed that the sensitivity of a combined therapy using triptolide and HCPT was higher than that of triptolide or HCPT alone and that activation of caspase-9/caspase-3 and inhibition of nuclear factor-kappaB (NF-κB) signaling pathway may contribute to the synergistic cytotoxic effect of this combination therapy. Therefore, our observations provided evidence supporting the clinical applications of the combination chemotherapy using triptolide and HCPT for treating pancreatic cancer.


Subject(s)
Antineoplastic Agents, Phytogenic/therapeutic use , Camptothecin/therapeutic use , Diterpenes/therapeutic use , Pancreatic Neoplasms/drug therapy , Phenanthrenes/therapeutic use , Phytotherapy , Plant Extracts/therapeutic use , Tripterygium/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Antineoplastic Combined Chemotherapy Protocols , Camptothecin/pharmacology , Caspase 3/metabolism , Caspase 9/metabolism , Cell Line, Tumor , Diterpenes/pharmacology , Drug Synergism , Epoxy Compounds/pharmacology , Epoxy Compounds/therapeutic use , Humans , NF-kappa B/metabolism , Pancreatic Neoplasms/metabolism , Phenanthrenes/pharmacology , Plant Extracts/pharmacology , Signal Transduction/drug effects
12.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 39(1): 71-8, 2010 01.
Article in Chinese | MEDLINE | ID: mdl-20175239

ABSTRACT

OBJECTIVE: To construct a recombinant adenovirus vector containing bone morphogenic protein-7 (BMP-7) gene and to identify its biological activities in proximal tubule epithelial cells (PTECs). METHODS: Forty-six fragments of BMP-7 gene were obtained by PCR method and then were ligated to the full-length gene. The full length sequence of BMP-7 was subcloned into pBluescript II(+) vectors, and confirmed by sequencing. Double digested with Not I and Hind III, BMP-7 gene was inserted into pShuttle-CMV. EcoR I pre-linearized pShuttle plasmid was transformed into competence bacterium BJ5183 to obtain the recombinant adenovirus-BMP-7 by efficient homologous recombination. Then the AdBMP-7 was obtained by packaging Pac I linearized in 293 cells. Adenoviral titer was determined by adenovirus fluorescent detection kit. The protein expression of BMP-7 in PTECs was respectively detected by ELISA and Western blot. RT-PCR method was used for analyzing the alpha-smooth muscle action (alpha-SMA) expression in PTECs, which was treated consecutively with TGF-beta and AdBMP-7. RESULTS: The recombinant plasmid AdBMP-7 was successfully generated, which increased BMP-7 protein expression levels in PTECs, and down-regulated TGF-beta-induced alpha-SMA expression. CONCLUSION: The bioactive recombinant adenovirus AdBMP-7 has been successfully constructed, which may be effective in inhibition of chronic renal fibrosis.


Subject(s)
Adenoviridae/metabolism , Bone Morphogenetic Protein 7/biosynthesis , Epithelial Cells/metabolism , Genetic Vectors/genetics , Kidney Tubules, Proximal/metabolism , Adenoviridae/genetics , Animals , Base Sequence , Bone Morphogenetic Protein 7/genetics , Cells, Cultured , Kidney Tubules, Proximal/cytology , Molecular Sequence Data , Rats , Recombinant Proteins/biosynthesis , Recombinant Proteins/genetics
13.
J Zhejiang Univ Sci B ; 11(2): 136-43, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20104648

ABSTRACT

OBJECTIVE: To understand the function of nicotinamide N-methyltransferase (NNMT) protein as tumor biomarker in renal carcinoma. METHODS: Recombinant NNMT protein was used to prepare monoclonal antibodies by hybridoma technique. The diagnostic and prognostic function of NNMT protein in renal carcinoma was evaluated by analyzing 74 renal cancer tissues through immunohistochemical staining for NNMT by using the prepared antibodies. RESULTS: Two hybridomas named 2F8 and 1E7 stably secreting the monoclonal antibodies were isolated successfully, and characters such as isotypes and specificity were determined. NNMT protein was significantly up-regulated in renal cancer and significantly associated with tumor histology and ages. The univariate survival analysis demonstrated that the pT-status, high levels of NNMT, and distant metastasis were significant prognosticators. CONCLUSION: NNMT is over-expressed in a large proportion in renal cell cancers. High NNMT expression is significantly associated with unfavorable prognosis. However, the prognostic value of NNMT needs further verification in larger sample sizes.


Subject(s)
Carcinoma, Renal Cell/enzymology , Kidney Neoplasms/enzymology , Nicotinamide N-Methyltransferase/metabolism , Adult , Aged , Animals , Antibodies, Monoclonal , Biomarkers, Tumor/immunology , Biomarkers, Tumor/metabolism , Carcinoma, Renal Cell/diagnosis , China , Female , Humans , Immunohistochemistry , Kidney Neoplasms/diagnosis , Male , Mice , Middle Aged , Nicotinamide N-Methyltransferase/immunology , Prognosis
14.
Huan Jing Ke Xue ; 31(11): 2666-72, 2010 Nov.
Article in Chinese | MEDLINE | ID: mdl-21250449

ABSTRACT

The changes of the different phosphorus (P) forms in sediments, overlying water and the diversity of dry weight and root forms of Myriophyllum spicatum were studied using different type sediments under simulating condition. The characteristic of transformation of P forms and growth of submerged plant Myriophyllum spicatum were illustrated. The results indicated that the P release was promoted by adding the silver sand in sediment, and their P concentrations in the overlying water were increased. The chemical characteristic of the sediments were changed by adding NH4 Cl, which restrained the P release from their sediments and decreased the P concentration in their overlying water. About 49%, 107% of their plant, root dry weight and 19% root length of Myriophyllum spicatum from different treatments were raised by adding silver sand in sediments. The root growths of the Myriophyllum spicatum from different treatments were restrained and their agings were promoted by adding NH4 Cl in sediments. The P release from sediments were accelerated by the growth of Myriophyllum spicatum, and the early decay of Myriophyllum spicatum can increase the P accumulation in sediment. The changing trend of different P forms in the sediments decreased firstly, and then increased with the Myriophyllum spicatum growthing, their contents of Fe/Al-P form in sediments varied greatly (41%-57%). The P release and adsorption in sediments were mainly affected by their root length index of Myriophyllum spicatum from different treatments. The P release in sediment was accelerated through their changing penetrate capacity by root diameter increasing.


Subject(s)
Geologic Sediments/chemistry , Magnoliopsida/growth & development , Phosphorus/chemistry , Water Pollutants, Chemical/chemistry , Biodegradation, Environmental , China , Eutrophication , Fresh Water/analysis , Magnoliopsida/drug effects , Phosphorus/metabolism , Water Pollutants, Chemical/metabolism
15.
Zhongguo Zhong Yao Za Zhi ; 31(14): 1188-91, 2006 Jul.
Article in Chinese | MEDLINE | ID: mdl-17048592

ABSTRACT

OBJECTIVE: To investigate the effect of Rongshi granule on osteopontin(OPN) expression. METHOD: The urlisthiasis rats were induced by ethylene glycol (EG) and ammonium chloride, the control group rats were non-treated, and the Rongshi granule groups (low-dose group, middle-dose group and high-dose group) were administered Rongshi granule in addition to EG and ammonium chloride in 21 days. Pooled 24 h urine samples from each group were collected weekly with the use of metabolic cages, the concentration of uric calcium and oxalic acid were respectively measured by EDTA and photoelectric colorimetric method. Eight animals from each group were killed at 0, 7, 14, and 21 days, kidneys were histologic examinaed and immunohistochemical staining. RESULT: The expression of kidney osteopontin in model group was obviously higher than that of control group (P <0.01), and was up to the highest at 21 days with 1.4 times (0.281 3/0.201 8) of the control group. The expression of kidney osteopontin in all of the Rongshi granule groups were lower than those of model group (P < 0.05), with an obvious dose-dependent manner. The degree of the kidney calcium oxalate crystal of the rats in all the Rongshi granule groups was much lower than that of model group, and the uric calcium and oxalic acid were much lower than those of model group (P < 0.01). CONCLUSION: The Rongshi granule could inhibit the expression of osteopontin in rat urolithiasis model.


Subject(s)
Drugs, Chinese Herbal/pharmacology , Kidney Calculi/metabolism , Kidney/metabolism , Osteopontin/metabolism , Plants, Medicinal , Ammonium Chloride , Animals , Calcium/urine , Calcium Oxalate/metabolism , Dose-Response Relationship, Drug , Drug Combinations , Drugs, Chinese Herbal/administration & dosage , Drugs, Chinese Herbal/isolation & purification , Ethylene Glycol , Female , Kidney Calculi/chemically induced , Male , Oxalic Acid/urine , Plants, Medicinal/chemistry , Random Allocation , Rats , Rats, Sprague-Dawley
16.
Huan Jing Ke Xue ; 26(2): 152-6, 2005 Mar.
Article in Chinese | MEDLINE | ID: mdl-16004319

ABSTRACT

The effects of nitrogen and phosphorus on the growth of Microcystis aeruginosa were investigated by using the Monod equation. The semi-saturation constants of Microcystis aeruginosa to TP (KsP) and TN (KsN) were calculated. The results show that KsN is higher than KsP. This indicates that the effect of TP on the growth of Microcystis aeruginos is further more significant than that of TN. Further analysis finds that extant quantity (X) and special growth rate (micro) of Microcystis aeruginosa increase with TP or TN, and there exists a point of inflection. When the concentrations of TP and TN ranged from 0.005mg/L to 0.2mg/L and from 0.01mg/L to 2mg/L respectively with TP or TN as the single limiting substrate, the growth rate of Microcystis aeruginosa increased rapidly. Because Microcystis aeruginosa exhibits different affinity with TP and TN (according to the semi-saturation constants), the effect of N/P ratio on the growth of Microcystis aeruginosa does not demonstrate at a constant value. No constant ratio can be used to determine the limiting nutrient elements on the growth of Microcystis aeruginosa in any aquatic environment. The effect of N/P ratio on the growth of Microcystis aeruginosa depends on both the N and P concentrations and the N/P ratio.


Subject(s)
Eutrophication , Microcystis/drug effects , Phosphorus/pharmacology , Water Pollutants/analysis , Water Purification/methods , Fresh Water/analysis , Microcystis/cytology , Nitrogen/pharmacology , Phytoplankton/cytology
SELECTION OF CITATIONS
SEARCH DETAIL
...