Ganoderic acids alleviate atherosclerosis by inhibiting macrophage M1 polarization via TLR4/MyD88/NF-κB signaling pathway.

BACKGROUND AND AIMS: Atherosclerosis (AS) is a chronic inflammatory disease characterized by lipid infiltration and plaque formation in blood vessel walls. Ganoderic acids (GA), a class of major bioactive compounds isolated from the Chinese traditional medicine Ganoderma lucidum, have multiple pharmacological activities. This study aimed to determine the anti-atherosclerotic effect of GA and reveal the pharmacological mechanism. METHODS: ApoE-/- mice were fed a high-cholesterol diet and treated with GA for 16 weeks to induce AS and identify the effect of GA. Network pharmacological analysis was performed to predict the anti-atherosclerotic mechanisms. An invitro cell model was used to explore the effect of GA on macrophage polarization and the possible mechanism involved in bone marrow dereived macrophages (BMDMs) and RAW264.7 cells stimulated with lipopolysaccharide or oxidized low-density lipoprotein. RESULTS: It was found that GA at 5 and 25 mg/kg/d significantly inhibited the development of AS and increased plaque stability, as evidenced by decreased plaque in the aorta, reduced necrotic core size and increased collagen/lipid ratio in lesions. GA reduced the proportion of M1 macrophages in plaques, but had no effect on M2 macrophages. In vitro experiments showed that GA (1, 5, 25 µg/mL) significantly decreased the proportion of CD86+ macrophages and the mRNA levels of IL-6, IL-1ß, and MCP-1 in macrophages. Experimental results showed that GA inhibited M1 macrophage polarization by regulating TLR4/MyD88/NF-κB signaling pathway. CONCLUSIONS: This study demonstrated that GA play an important role in plaque stability and macrophage polarization. GA exert the anti-atherosclerotic effect partly by regulating TLR4/MyD88/NF-κB signaling pathways to inhibit M1 polarization of macrophages. Our study provides theoretical basis and experimental data for the pharmacological activity and mechanisms of GA against AS.

Bioactive pterocarpans from the root of Astragalus membranaceus var. mongholicus.

Eleven undescribed and three known pterocarpans were isolated and identified from the traditional Chinese medicine "Huang-qi", Astragali Radix (the root of Astragalus membranaceus var. mongholicus (Bunge) P.K.Hsiao). The structures of these pterocarpans were determined using spectroscopic, X-ray crystallographic, quantum chemical calculation, and chemical methods. Pterocarpans, almost exclusively distributed in the family of Leguminosae, are the second largest subgroup of isoflavanoids. However, pterocarpan glycoside number is limited, most of which are glucosides, and only one pterocarpan apioside was isolated from nature. Notably, nine rare apiosyl-containing pterocarpan glycosides were isolated and identified. The hypoglycemic activities of all these compounds were evaluated using α-glucosidase and DPP-IV inhibitory assays respectively, and some isolates displayed the α-glucosidase inhibitory function. The antioxidant activities of all compounds were evaluated using the ORAC and DPPH radical scavenging assays, respectively. All compounds exhibited varying degrees of oxygen radical absorbance capacity, and some compounds displayed DPPH radical scavenging ability.

Ganoderic acid alleviates chemotherapy-induced fatigue in mice bearing colon tumor.

Chemotherapy-related fatigue (CRF) is increasingly being recognized as one of the severe symptoms in patients undergoing chemotherapy, which not only largely reduces the quality of life in patients, but also diminishes their physical and social function. At present, there is no effective drug for preventing and treating CRF. Ganoderic acid (GA), isolated from traditional Chinese medicine Ganoderma lucidum, has shown a variety of pharmacological activities such as anti-tumor, anti-inflammation, immunoregulation, etc. In this study, we investigated whether GA possessed anti-fatigue activity against CRF. CT26 tumor-bearing mice were treated with 5-fluorouracil (5-FU, 30 mg/kg) and GA (50 mg/kg) alone or in combination for 18 days. Peripheral and central fatigue-related behaviors, energy metabolism and inflammatory factors were assessed. We demonstrated that co-administration of GA ameliorated 5-FU-induced peripheral muscle fatigue-like behavior via improving muscle quality and mitochondria function, increasing glycogen content and ATP production, reducing lactic acid content and LDH activity, and inhibiting p-AMPK, IL-6 and TNF-α expression in skeletal muscle. Co-administration of GA also retarded the 5-FU-induced central fatigue-like behavior accompanied by down-regulating the expression of IL-6, iNOS and COX2 in the hippocampus through inhibiting TLR4/Myd88/NF-κB pathway. These results suggest that GA could attenuate 5-FU-induced peripheral and central fatigue in tumor-bearing mice, which provides evidence for GA as a potential drug for treatment of CRF in clinic.

Relationship between consumption of raw garlic and handgrip strength in a large-scale adult population.

BACKGROUND: Garlic-derived organosulfur compounds have numerous potential benefits (e.g. antioxidant and anti-inflammatory effects) on human health. Although these functions might be related to the onset and progression of muscle strength decline, no studies have explored the relationship between garlic consumption and muscle strength in the general population. The aim of this study was to investigate whether raw garlic consumption is related to handgrip strength in a large-scale adult population. METHODS: A cross-sectional study (n = 28,958) was performed in Tianjin, China. Frequency of raw garlic consumption was assessed using a valid self-administered food frequency questionnaire. Handgrip strength was measured using a handheld digital dynamometer. Analysis of covariance and multiple logistic regression were used to evaluate the relationship between raw garlic consumption and handgrip strength. RESULTS: In males, after adjusted potential confounding factors, the least square means (95% confidence intervals) of handgrip strength across raw garlic consumption categories were 42.5 (40.2-44.9) for almost never; 43.0 (40.7-45.5) for <1 time/week; 43.4 (41.0-45.8) for 1 time/week; and 43.8 (41.5-46.3) for ≥2-3 times/week (P for trend <0.0001). The adjusted odds ratios (95% confidence intervals) of low handgrip strength (<20th percentile of handgrip strength) across the categories of raw garlic consumption in males were 1.00, 0.86 (0.76, 0.98), 0.76 (0.67, 0.87), and 0.66 (0.58, 0.74) (P for trend <0.0001). Similar results were also observed in females. CONCLUSIONS: The study firstly revealed a positive correlation between raw garlic consumption and handgrip strength in both males and females. Further studies are needed to explore the casual relationship.

Raw garlic consumption is inversely associated with prehypertension in a large-scale adult population.

Previous studies have shown that allicin can lower blood pressure (BP) by reducing oxidative stress and inflammation. However, the association between habitual raw garlic intake (as allicin source) and prehypertension are unclear. The aim of this study was to investigate how raw garlic consumption is associated with prehypertension in an adult population. A cross-sectional study was conducted with 22,812 adults (mean [standard deviation] age: 39.4 [10.7] years; males, 47.7%) in Tianjin, China. Raw garlic consumption was assessed using a validated food frequency questionnaire. BP was measured at least twice by trained nurses using an automatic device. Prehypertension was defined as systolic BP of 120-139 mmHg and/or diastolic BP of 80-89 mmHg without taking antihypertensive medication. Multiple logistic regression models were used to assess the association between raw garlic consumption and prehypertension. The prevalence of prehypertension was 49.9%. After fully adjusting for potential confounders, the ORs (95% confidence intervals) of having prehypertension by increasing frequency of raw garlic consumption were 1.00 (reference) for ≤3 times/week, 0.96 (0.87, 1.06) for 4 times/week to 1 time/day, and 0.69 (0.52, 0.90) for ≥2 times/day (p for trend = 0.06). In contrast, no associations were observed between other kinds of allium vegetables consumption and prehypertension. In conclusion, our results suggested that a more frequent consumption of raw garlic was inversely associated with prehypertension. This is the first large-scale study on the association between raw garlic consumption and prehypertension in the general population.

Daily tea drinking is not associated with newly diagnosed non-alcoholic fatty liver disease in Chinese adults: the Tianjin chronic low-grade systemic inflammation and health cohort study.

BACKGROUND: Previous studies have reported that tea extract supplementation has potential benefits on the risk factors of non-alcoholic fatty liver disease (NAFLD); however, no study has investigated the direct effect of daily tea consumption on the prevalence of NAFLD in the general population. This cross-sectional study aimed to evaluate the associations between tea consumption and the prevalence of newly diagnosed NAFLD among Chinese adults. METHODS: The present cross-sectional study was based on the Tianjin Chronic Low-grade Systemic Inflammation and Health Cohort Study. In total, 19,350 participants were enrolled in the analyses. Tea consumption was assessed via a self-administered food frequency questionnaire. NAFLD was diagnosed via liver ultrasonography and no history of heavy alcohol intake. Logistic regression analysis was used to estimate the associations between tea consumption and the prevalence of NAFLD. RESULTS: Consumption of green tea, oolong tea, and black tea were positively associated with the prevalence of newly diagnosed NAFLD before adjustments. Compared with the participants who never drink tea, the odds ratios (95% confidence interval) of newly diagnosed NAFLD in the highest categories (≥ 1 cup/day) of green tea, oolong tea, black tea, and jasmine tea were 1.48 (1.33, 1.65), 1.50 (1.33, 1.68), and 1.28 (1.13, 1.46), and 1.36 (1.20, 1.54) before adjustments, respectively. However, no significant association was found between tea consumption and the prevalence of NAFLD after adjusting for socio-demographic, behavioural, anthropometric, dietary, and clinical confounding factors. CONCLUSION: There is no significant association between daily tea drinking and newly-diagnosed NAFLD in general Chinese adults.

Association between dietary raw garlic intake and newly diagnosed nonalcoholic fatty liver disease: a population-based study.

BACKGROUND AND AIMS: The protective effect of garlic against nonalcoholic fatty liver disease (NAFLD) has been reported in animal studies. However, in humans, the association between garlic consumption and NAFLD is unclear. The study sought to explore the association between habitual raw garlic intake and newly diagnosed NAFLD among Chinese adults. METHODS: We performed a study of 11,326 men and 12,780 women aged 20-90 years. Habitual food intake was assessed using a validated and standardized 100-item food frequency questionnaire. Diagnosis of NAFLD was based on the liver ultrasonography and self-reported alcohol intake. Multiple logistic regression was used to evaluate the association of raw garlic intake with newly diagnosed NAFLD. RESULTS: The prevalence of newly diagnosed NAFLD was 28.9% in men and 10.1% in women, respectively. In men, the fully adjusted odds ratios (95% confidence interval) of having NAFLD across increasing frequency of raw garlic intake were 1.00 (reference) for <1 time/week, 0.81 (0.73, 0.90) for 1-3 times/week, 0.66 (0.54, 0.80) for 4-6 times/week, and 0.71 (0.55, 0.90) for ≥7 times/week (P for trend <0.0001). The odds ratio for NAFLD associated with each 1 g of raw garlic/1000 kcal was 0.93 (0.90, 0.97) in men. In women, no significant association between raw garlic intake and NAFLD was identified. These associations between raw garlic intake and NAFLD were consistent in several sensitivity analyses. CONCLUSIONS: Frequent consumption of raw garlic is inversely associated with NAFLD in Chinese men. Further investigations are needed to confirm this finding.

Dietary myricetin intake is inversely associated with the prevalence of type 2 diabetes mellitus in a Chinese population.

Myricetin is a natural plant-derived inhibitor for α-glucosidase and α-amylase and possesses strong antioxidant activity. Myricetin is reported to be effective in treating many symptoms that are associated with type 2 diabetes mellitus (T2DM), therefore, we hypothesized that myricetin plays a preventive role in the development of T2DM. To test this hypothesis, we designed a cross-sectional population study, which included 24 138 subjects, with 1357 of them diagnosed with T2DM. A validated 100-item food frequency questionnaire was used to collect dietary information. Daily intakes of myricetin and nutrients were calculated, based on the Chinese food composition tables. Multiple logistic regression analysis models were used to analyze the relationship between the quartiles of myricetin intake and the prevalence of T2DM. We found that, in this Chinese population, the daily intake of myricetin was 120.5 ±â€¯95.7 mg, with apple, peach, orange, pineapple, and sweet potato being the main food sources. Significant inverse trends were observed between intakes of myricetin and prevalence of T2DM in multivariable models (all p-trend <0.0001). The odds ratios (95% CI) for T2DM across the ascending quartiles of myricetin intake were: 1.00 (reference), 0.73 (0.61, 0.87), 0.61 (0.50, 0.75), and 0.51 (0.40, 0.64). This study showed that myricetin intake was inversely related to the prevalence of T2DM in this Chinese population, suggesting a protective effect of myricetin in the development of T2DM.

Electromyographic bridge for promoting the recovery of hand movements in subacute stroke patients: A randomized controlled trial.

OBJECTIVE: The electromyographic bridge (EMGB) detects surface electromyographic signals from a non-paretic limb. It then generates electric pulse trains according to the electromyographic time domain features, which can be used to stimulate a paralysed or paretic limb in real time. This strategy can be used for the contralateral control of neuromuscular electrical stimulation (NMES) to improve motor function after stroke. The aim of this study was to compare the treat-ment effects of EMGB vs cyclic NMES on wrist and finger impairments in subacute stroke patients. METHODS: A total of 42 hemiplegic patients within 6 months of their cerebrovascular accidents were randomly assigned to 4-week treatments with EMGB or cyclic NMES. Each group underwent a standard rehabilitation programme and 10 sessions per week of hand training with EMGB or cyclic NMES. Outcome measures were: Brunnstrom stage, upper extremity components of the Fugl-Meyer Assessment, Motor Status Scale, voluntary surface electromyographic ratio and active range of motion of the wrist and finger joints. RESULTS: The EMGB group showed significantly greater improvements than the cyclic NMES group on the following measures: Brunnstrom stages for the hand, upper extremity - Fugl-Meyer Assessment, Motor Status Scale, and the voluntary surface electromyographic ratio of wrist and finger extensors. Eleven and 4 participants of the EMGB group who had no active wrist and finger movements, respectively, at the start of the treatment could perform measurable wrist and finger extensions after EMGB training. The corresponding numbers in the cyclic NMES group were only 4 and 1. CONCLUSION: In the present group of subacute stroke patients, the results favour EMGB over cyclic NMES for augmenting the recovery of volitional wrist and finger motion.

A microbial model of mammalian metabolism: biotransformation of 4,5-dimethoxyl-canthin-6-one using Cunninghamella blakesleeana CGMCC 3.970.

1. A filamentous fungus, Cunninghamella blakesleeana CGMCC 3.970, was applied as a microbial system to mimic mammalian metabolism of 4,5-dimethoxyl-canthin-6-one (1). Compound 1 belongs to canthin-6-one type alkaloids, which is a major bioactive constituent of a traditional Chinese medicine (the stems of Picrasma quassioides). 2. After 72 h of incubation in potato dextrose broth, 1 was metabolized to seven metabolites as follows: 4-methoxyl-5-hydroxyl-canthin-6-one (M1), 4-hydroxyl-5-methoxyl-canthin-6-one (M2), canthin-6-one (M3), canthin-6-one N-oxide (M4), 10-hydroxyl-4,5-dimethoxyl-canthin-6-one (M5), 1-methoxycarbonl-ß-carboline (M6), and 4-methoxyl-5-O-ß-D-glucopyranosyl-canthin-6-one (M7). 3. The structures of metabolites were determined using spectroscopic analyses, chemical methods, and comparison of NMR data with those of known compounds. Among them, M7 was a new compound. 4. The metabolic pathways of 1 were proposed, and the metabolic processes involved phase I (O-demethylation, dehydroxylation, demethoxylation, N-oxidation, hydroxylation, and oxidative ring cleavage) and phase II (glycosylation) reactions. 5. This was the first research on microbial transformation of canthin-6-one alkaloid, which could be a useful microbial model for producing the mammalian phase I and phase II metabolites of canthin-6-one alkaloids. 6. 1, M1-M5, and M7 are canthin-6-one alkaloids, whereas M6 belongs to ß-carboline type alkaloids. The strain of Cunninghamella blakesleeana can supply an approach to transform canthin-6-one type alkaloids into ß-carboline type alkaloids.

[C:N:P stoichiometry characteristics of litter and soil of forests in Great Xing'an Mountains with different fire years.] / å¤§å ´å®‰å²­ä¸åŒç«çƒ§å¹´é™æ£®æž—å‡‹è½ç‰©å’ŒåœŸå£¤C、N、P化学计量特征.

We investigated the fire impacts on nutrients in litter and soil, and their C:N:P stoichio-metry in forests of Great Xing'an Mountains. The studied sites differed in their burning year (post-fire 4, 14, 40, 70 years and unburned within 120 years) and had different topographic locations (sloped land and flat land). The results showed that there were significant differences in stoichio-metry characteristics of C, N, P for both litter and soil with different burning years. No significant fluctuation was observed for the litter C content, while the contents of litter N and P increased with the increasing post-fire recovery years. In specific, we found the contents of litter N and P decreased at post-fire 4 and 14 years and nearly recovered to the control level at 40 years after fire. Additionally, C:N and C:P ratios of litter decreased, but N:P ratio of litter increased following post-fire recovery time. The contents of C, N, P and their ratios (C:N, C:P and N:P) in soil decreased with soil depth. Soil C content exhibited an increasing trend following post-fire recovery time and was significantly higher than the control at post-fire 70 years in sloped land, but no significant difference in the flat land. Significant interactive effects between fire history and slope were observed in soil P content and C:P ratio. Soil P content was higher than the control at post-fire 4 years in sloped land, but was higher than the control at post-fire 40 years in flat land. The C:P ratio recovered to the control level at post-fire 14 years in sloped land, and there was no significant diffe-rence in flat land. Redundancy analysis showed that slope effect played a more vital role than fire history effect in soil organic layer, while fire history effect was the most important factor for the varia-tion of soil nutrients in soil mineral layer. In our study, nutrients of litter and soil were lower than the control level at post-fire 4 and 14 years. The quality of litter and soil was improved with accele-rated plant growth and litter decomposition following post-fire recovery time and recovered to the pre-fire level at post-fire 40 years, reaching a steady status.

A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features.

OBJECTIVE: Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. APPROACH: We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. MAIN RESULTS: The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. SIGNIFICANCE: Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle force reproduction and muscle fatigue reduction.

[Studies of effective part group of piperine to regulating lipid].

The effects of effective part group on hyperlipidemia in animal were studied. The SD rats, hamsters and Kunming mouse were divided into blank group, model group. The positive control group and test group were fed with normal diet, blank and other groups were fed with high fat diet (mouse only a single intraperitoneal injection of egg yolk ). The corresponding concentration of solvent, simvastatin, effective part group of emulsion were given gavage once daily. The animal serum total cholesterol (TC) , triglyceride (TG) , low density lipoprotein (LDL) , high density lipoprotein (HDL) and liver TC, TG contents were determined to observe the effects of the effective fractions on blood lipid regulating function. Comparing with control group, the animial hyperlipidemia models of the SD rat (TC increase), mouse (TC, TG, LDL increase), hamsters ( TC, TG, LDL increase, HDL decrease) (P <0. 05, P < 0. 001) were successfully established. Piper longum effective part group could decrease the serum TC, TG, LDL (P <0.05, P < 0. 001) and liver TC, TG content, and elevate serum HDL levels (P <0.05, P <0.001). The golden hamster is ideal for hyperlipidemia model.

[Clinical study on the treatment of knee osteoarthritis by acupuncture plus manipulative regulation of knee muscle].

OBJECTIVE: To investigate and research the appraisal scores of the symptoms and physical signs index for the evaluation of the clinical efficacy of acupuncture and manipulative regulation of knee muscle balance for the treatment of knee osteoarthritis, and provide clinical basis for the treatment. METHODS: From January 2008 to December 2009, 121 patients with knee osteoarthritis were randomly divided into two groups. In the treatment group there were 63 cases of 83 knees including 16 males and 47 females, with an average age of (59.88 +/- 7.97) years; in the control group there were 58 cases of 73 knees including 13 males and 45 females, with an average age of (57.95 +/- 10.37) years. The patients in the treatment group were treated with acupuncture plus manipulative regulation of knee muscle balance, and the patients in the control group were treated with Diclofenac Sodium Sustained Release Tablets. The appraisal scores of the symptoms and physical signs index, numerical rating scale of pain, joint function, joint swelling were evaluated before and after the treatment, as well as 3 months after the treatment. All data were statistical analyzed by package SPSS 10.0. RESULTS: 1) In the treatment group, before and after treatment the appraisal scores of the symptoms and physical signs index were (39.81 +/- 3.92) and (9.69 +/- 8.08); numerical rating scale of pain were (7.61 +/- 0.97) and (2.17 +/- 2.09); joint function were (1.47 +/- 0.50) and (0.61 +/- 0.58); joint swelling were (1.23 +/- 0.79) and (0.42 +/- 0.52). As well in the control group, above data were (39.89 +/- 3.78), (13.62 +/- 7.83), (7.55 +/- 0.71), (3.34 +/- 2.32), (1.33 +/- 0.47), (0.93 +/- 0.67), an (0.97 +/- 0.88), (0.58 +/- 0.52) respectively. Both group had obvious differences in the appraisal scores of the symptoms and physical signs index, numerical rating scale of pain, joint function, joint swelling between after and before treatment. The comparison between the two groups suggested that after the treatments the treatment group had better therapy effect than those of the control group in the appraisal scores of the symptoms and physical signs index, numerical rating scale of pain, joint function, but both group had no differences in the appraisal scores of joint swelling. 2) After the treatment, 12 patients in the treatment group were clinically cured, 48 had remarkable effects,19 good, and 4 ineffective. As well in the control group, above data were 5, 31, 34 and 3 respectively. Three months after the treatment, above data were 8, 42, 27 and 6 respectively in the treatment group. In the control group, above data were 5, 21, 37 and 10 respectively. The treatment group was superior to the control group after the treatments and 3 months after the treatment. CONCLUSION: Acupuncture plus manipulative regulation of knee muscle balance can effectively improve the clinical symptoms and knee joint's motor function of patients with knee osteoarthritis, and can avoid the further development of disease. It is a proved effective method for knee osteoarthritis.

Andrograpanin, isolated from Andrographis paniculata, exhibits anti-inflammatory property in lipopolysaccharide-induced macrophage cells through down-regulating the p38 MAPKs signaling pathways.

Andrographis paniculata Nees is an official herbal medicine for treatment of infection and inflammation in China. Andrograpanin, the one of diterpene lactones in A. paniculata, is a hydrolysate from neoandrographolide in vivo and in vitro. The goal of the present study was to investigate andrograpanin which effects on over production of nitric oxide (NO) and pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-12p70) and the key signaling pathways involved in lipopolysaccharide (LPS)-activated macrophage cells. The results showed that NO and all three pro-inflammatory cytokines were inhibited by andrograpanin (15-90 microM) in a dose-dependent manner. The RT-PCR and western blotting assays showed that andrograpanin inhibited productions of NO and pro-inflammatory cytokines through down-regulating iNOS and pro-inflammatory cytokines gene expression levels. Further studies suggested that down-regulation of p38 mitogen-activated protein kinase (MAPKs) signaling pathways were involved in the anti-inflammatory activities of andrograpanin. This study provided evidences that andrograpanin might be useful as a potential anti-inflammatory leading compound for inflammatory drug development.

Effects of iron and phosphorus on Microcystis physiological reactions.

OBJECTIVE: To observe the effects of iron and phosphorus on Microcystis physiological reactions. METHODS: The experimental conditions were chosen as the light dark cycles of 16 h 8 h, 12 h 12 h, and 8 h 16 h. The cell change of morphology and life history, cell number, cell color, and cell area of Microcystis were analyzed quantitatively. According to the resource competition and Monod equation, Microcystis kinetics of phosphorus and iron were also examined. RESULTS: The longer light time caused more special cell division, slower growth rate, and easier change of bigger cell area. The color of alga was changed from green to brown. Ks and micromax of phosphorus absorption were 0.0352 mircomol x L(-l) and 0.493 d(-1), respectively. Those of iron absorption were 0.00323 micromol x L(-1) and 0.483 d(-1). CONCLUSION: Microcystis bloom is more dominant than other algae.

Effects of iron and phosphorus on Microcystis physiological reactions / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To observe the effects of iron and phosphorus on Microcystis physiological reactions.</p><p><b>METHODS</b>The experimental conditions were chosen as the light dark cycles of 16 h 8 h, 12 h 12 h, and 8 h 16 h. The cell change of morphology and life history, cell number, cell color, and cell area of Microcystis were analyzed quantitatively. According to the resource competition and Monod equation, Microcystis kinetics of phosphorus and iron were also examined.</p><p><b>RESULTS</b>The longer light time caused more special cell division, slower growth rate, and easier change of bigger cell area. The color of alga was changed from green to brown. Ks and micromax of phosphorus absorption were 0.0352 mircomol x L(-l) and 0.493 d(-1), respectively. Those of iron absorption were 0.00323 micromol x L(-1) and 0.483 d(-1).</p><p><b>CONCLUSION</b>Microcystis bloom is more dominant than other algae.</p>

Effects of nutrients on Microcystis growth more easily forming bloom.

Different nutrient media experimentally were N, P and Fe-limited conditions and a serial of diluted BG11 media. The cell change of morphology and life history, cell number, cell color and cell area of Microcystis were analyzed quantitatively. First, the effects of nitrogen, phosphorus and iron depletion were distinctively different. Phosphorus and iron depletion caused more special division cells, slowly growth increasing, the easier change of bigger cell area. Second, the nitrogen and iron depletion could make the color of alga from green to brown. Finally, according to the resource competition and Monod equation, Microcystis kinetics of phosphorus and iron were also examined. K(s) and micro(max) of phosphorus absorption were 0.0352 micromol/L, 0.493 d(-1) respectively; iron absorption: 0.00323 micromol/L, 0.483 d(-1). In a word, some evidences of the Microcystis bloom dominance in certain nutrient conditions were indicated in the experiments. The dominances were determined as the reviving under the adverse circumstances through the special division, the various nitrogen resources, and the lower kinetics of phosphorus and iron than that of most of other algae. The conclusions provided the scientific basis for preventing and managing Microcystis bloom in freshwater.