Robotic Actuation-Mediated Quantitative Mechanogenetics for Noninvasive and On-Demand Cancer Therapy.

Cell mechanotransduction signals are important targets for physical therapy. However, current physiotherapy heavily relies on ultrasound, which is generated by high-power equipment or amplified by auxiliary drugs, potentially causing undesired side effects. To address current limitations, a robotic actuation-mediated therapy is developed that utilizes gentle mechanical loads to activate mechanosensitive ion channels. The resulting calcium influx precisely regulated the expression of recombinant tumor suppressor protein and death-associated protein kinase, leading to programmed apoptosis of cancer cell line through caspase-dependent pathway. In stark contrast to traditional gene therapy, the complete elimination of early- and middle-stage tumors (volume ≤ 100 mm3) and significant growth inhibition of late-stage tumor (500 mm3) are realized in tumor-bearing mice by transfecting mechanogenetic circuits and treating daily with quantitative robotic actuation in a form of 5 min treatment over the course of 14 days. Thus, this massage-derived therapy represents a quantitative strategy for cancer treatment.

[Circadian rhythm and health: dialogue between traditional Chinese medicine and modern medicine].

Circadian rhythm refers to the daily rhythmic variations in an organism. The irregular lifestyles of modern humans have led to a high incidence of chronic diseases, highlighting an inseparable relationship between disrupted circadian rhythm and disease development. TCM has long discussed rhythmic variations, with records dating back to the Yellow Emperor's Inner Canon(Huang Di Nei Jing), which laid a rich theoretical foundation for the research on circadian rhythm. Modern medical research has provided a more comprehensive explanation of its molecular mechanisms. This article integrated the current understanding of circadian rhythm in both Chinese and western medicine, emphasizing the crucial relationship between rhythm regulation and disease treatment. By highlighting the interdisciplinary nature of the two fields, it offers new directions for exploring the field of chronomedicine.

Effects of different content of EGCG or caffeic acid addition on the structure, cooking, antioxidant characteristics and in vitro starch digestibility of extruded buckwheat noodles.

The effects of different types and content of polyphenol addition on the structure, cooking, antioxidant characteristics and in vitro starch digestibility of extruded buckwheat noodles were investigated in this study. The result showed epigallocatechin-3-gallate (EGCG) was more easily combined with starch to form complex than caffeic acid, and amylose tended to be combined with polyphenols to form more complex. Amylose had a protective effect on polyphenols during extrusion process, which led to a significant increase of polyphenol content and antioxidant activity of extruded noodles. The addition of polyphenol and high amylose corn starch (HACS) improved the cooking quality of extruded buckwheat noodles. The extruded buckwheat noodles with 20 % HACS and 1 % EGCG had the lowest cooking loss of 6.08 %. The addition of EGCG and HACS increased the content of resistant starch and reduced predicted glycemic index (pGI). The noodles with 20 % HACS and 3 % EGCG had the lowest pGI (63.38) and the highest resistant starch (RS) content (61.60 %). This study provides a theoretical basis for the development of low pGI extruded buckwheat noodles.

Comparison of Coated and Uncoated Trace Minerals on Growth Performance, Tissue Mineral Deposition, and Intestinal Microbiota in Ducks.

Abnormally low or high levels of trace elements in poultry diets may elicit health problems associated with deficiency and toxicity, and impact poultry growth. The optimal supplement pattern of trace mineral also impacts the digestion and absorption in the body. For ducks, the limited knowledge of trace element requirements puzzled duck production. Thus, the objective of this study was to investigate the influence of dietary inclusions of coated and uncoated trace minerals on duck growth performance, tissue mineral deposition, serum antioxidant status, and intestinal microbiota profile. A total of 1,080 14-day-old Cherry Valley male ducks were randomly divided into six dietary treatment groups in a 2 (uncoated or coated trace minerals) × 3 (300, 500, or 1,000 mg/kg supplementation levels) factorial design. Each treatment was replicated 12 times (15 birds per replicate). Coated trace minerals significantly improved average daily gain (p < 0.05), increased Zn, Se, and Fe content of serum, liver, and muscle, increased serum antioxidant enzyme (p < 0.05) and decreased the excreta Fe, Zn, and Cu concentrations. Inclusions of 500 mg/kg of coated trace minerals had a similar effect on serum trace minerals and tissue metal ion deposition as the 1,000 mg/kg inorganic trace minerals. Higher concentrations of Lactobacillus, Sphaerochatea, Butyricimonas, and Enterococcus were found in birds fed with coated trace minerals. In conclusion, diets supplemented with coated trace minerals could reduce the risk of environmental contamination from excreted minerals without affecting performance. Furthermore, coated trace minerals may improve the bioavailability of metal ions and the colonization of probiotic microbiota to protect microbial barriers and maintain gut health.

Disrupting Circadian Rhythm via the PER1-HK2 Axis Reverses Trastuzumab Resistance in Gastric Cancer.

Trastuzumab is the only approved targeted drug for first-line treatment of HER2-positive advanced gastric cancer, but the high rate of primary resistance and rapid emergence of secondary resistance limit its clinical benefits. We found that trastuzumab-resistant (TR) gastric cancer cells exhibited high glycolytic activity, which was controlled by hexokinase 2 (HK2)-dependent glycolysis with a circadian pattern [higher at zeitgeber time (ZT) 6, lower at ZT18]. Mechanistically, HK2 circadian oscillation was regulated by a transcriptional complex composed of PPARγ and the core clock gene PER1. In vivo and in vitro experiments demonstrated that silencing PER1 disrupted the circadian rhythm of PER1-HK2 and reversed trastuzumab resistance. Moreover, metformin, which inhibits glycolysis and PER1, combined with trastuzumab at ZT6, significantly improved trastuzumab efficacy in gastric cancer. Collectively, these data introduce the circadian clock into trastuzumab therapy and propose a potentially effective chronotherapy strategy to reverse trastuzumab resistance in gastric cancer. SIGNIFICANCE: In trastuzumab-resistant HER2-positive gastric cancer, glycolysis fluctuates with a circadian oscillation regulated by the BMAL1-CLOCK-PER1-HK2 axis, which can be disrupted with a metformin-based chronotherapy to overcome trastuzumab resistance.

Enhanced Reactive Blue 4 Biodegradation Performance of Newly Isolated white rot fungus Antrodia P5 by the Synergistic Effect of Herbal Extraction Residue.

In this study, a white rot fungus Antrodia was newly isolated and named P5. Then its dye biodegradation ability was investigated. Our results showed that P5 could effectively degrade 1,000 mg/L Reactive Blue 4 (RB4) in 24 h with 95% decolorization under shaking conditions. It could tolerate a high dye concentration of 2,500 mg/L as well as 10% salt concentration and a wide range of pH values (4-9). Herbal extraction residues (HER) were screened as additional medium elements for P5 biodegradation. Following the addition of Fructus Gardeniae (FG) extraction residue, the biodegradation performance of P5 was significantly enhanced, achieving 92% decolorization in 12 h. Transcriptome analysis showed that the expression of multiple peroxidase genes was simultaneously increased: Lignin Peroxidase, Manganese Peroxidase, Laccase, and Dye Decolorization Peroxidase. The maximum increase in Lignin Peroxidase reached 10.22-fold in the presence of FG. The results of UV scanning and LC-HRMS showed that with the synergistic effect of FG, P5 could remarkably accelerate the biodegradation process of RB4 intermediates. Moreover, the fungal treatment with FG also promoted the abatement of RB4 toxicity. In sum, white rot fungus and herbal extraction residue were combined and used in the treatment of anthraquinone dye. This could be applied in practical contexts to realize an efficient and eco-friendly strategy for industrial dye wastewater treatment.

Effect of ultrahigh pressure on structural and physicochemical properties of rice and corn starch in complexes with apple polyphenols.

BACKGROUND: Ultrahigh-pressure (UHP) treatment, a non-thermal processing technology, exerts a bactericidal effect and affects food texture. How UHP treatments influence starch-polyphenol complexes has not yet been reported. Here, we studied the effects of UHP treatment on the structure of common rice starch (CRS)-apple polyphenol (AP) and common corn starch (CCS)-AP mixtures. RESULTS: Overall, UHP treatment decreased the particle size of the CRS-AP and CCS-AP composites. Furthermore, the ΔH values of the CRS-AP and CCS-AP mixtures decreased, and the heating stability was improved after UHP treatment. X-ray diffraction indicated that the relative crystallinity of the mixtures was unaffected by UHP treatment. Fourier-transform infrared spectroscopy proved that no new absorption peaks were observed in the infrared spectra, and the order of starch-AP was decreased after UHP treatment. These results indicated that UHP treatment inhibited the retrogradation of the starch-AP mixture. Our analyses of the microstructures of CRS-AP and CCS-AP mixtures showed increased folding and more pronounced network structures under high-pressure. CONCLUSIONS: These results provide a theoretical basis for further exploring the properties of starch-AP mixtures following UHP treatment and provide insights regarding the use of UHP treatments for food production. © 2020 Society of Chemical Industry.

Quality Control of Psoralea corylifolia L. Based on High-Speed Countercurrent Chromatographic Fingerprinting.

Traditional Chinese medicine (TCM)has played an important role in promoting the health of Chinese people. The TCM Psoralea corylifolia L. has been used in the treatment of various kinds of diseases including enuresis, vitiligo, and calvities. However, therapeutic effects of P. corylifolia L. have often influenced by the quality of plants. So, it is very important to control the quality of P. corylifolia L. In this study, analytical high-speed countercurrent chromatography (HSCCC) was successfully used to fingerprint P. corylifolia L. Samples of P. corylifolia L. were extracted by ultrasonic extraction. n-hexane-ethyl acetate-methanol-water at a ratio of 5:5.5:6.5:5 (v/v) was selected as a two-phase solvent system and the condition of HSCCC were optimized in order to good separation. And the method of HSCCC was verified (reproducibility, precision, and stability). HSCCC chromatograms exhibited six common peaks, which were selected as indicator compounds for the quality control of P. corylifolia L. Within 20 types of medicinal materials, chemical components are similar, but the levels of components are quite different in HSCCC fingerprint. The present results demonstrate that the HSCCC method provides a reliable basis for the quality control of P. corylifolia L. and can also be applied to confirm the authenticity of plant materials.

Fingerprint Analysis of Cnidium monnieri (L.) Cusson by High-Speed Counter-Current Chromatography.

Cnidium monnieri (L.) Cusson is a popular Traditional Chinese Medicine (TCM) with a variety of bioactivities. However, there are some problems that have affected the development of Cnidium monnieri (L.) Cusson. At present, many methods have been reported for the analysis of coumarins in Cnidium monnieri (L.) Cusson. However, the quality control of coumarins in Cnidium monnieri (L.) Cusson by high-speed counter-current chromatography (HSCCC) has not been reported. In this study, analytical high-speed counter-current chromatography (HSCCC) was successfully used for fingerprint of Cnidium monnieri (L.) Cusson with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at 4:6:6.5:3.5 (v/v). The UV wavelength was set at 254 nm. Six coumarin compounds with high biological activity were selected as indicator compounds for the quality control. The HSCCC fingerprint of the Cnidium monnieri (L.) Cusson was successfully established and there were some differences according to the results of the fingerprint analysis. The present results demonstrate that HSCCC is an established and efficient technique for the fingerprint analysis of Cnidium monnieri (L.) Cusson and can be used to control the quality of Cnidium monnieri (L.) Cusson. In brief, HSCCC is a useful technology for the fingerprint analytical method for TCM.

Steroidal Saponins from Vernonia amygdalina Del. and Their Biological Activity.

In the present study, four new steroidal saponins, namely vernoniamyoside A-D (1-4), together with the two known steroidal saponins vernoamyoside D (5) and vernonioside B2 (6) were isolated from the ethanol extract of leaves of the African medicinal plant Vernonia amygdalina Del. (Asteraceae). Their structures were demonstrated by spectral analyses along with 1D and 2D nuclear magnetic resonance (NMR) techniques and mass spectrometry (MS). The cytotoxicity of the compounds was also tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method on the cell lines Hela, MCF-7, BT-549 and MDA-MB-231. Vernoniamyoside A, vernoniamyoside B, and vernonioside B2 showed cytotoxicity towards BT-549 cell lines. Vernoniamyoside C, vernoniamyoside D and vernoamyoside D showed different levels of cytotoxic activities.

Tea consumption is associated with cognitive impairment in older Chinese adults.

OBJECTIVE: To explore the association between tea consumption and cognitive impairment (CoI). METHODS: 4579 adults (≥60 years) from the Weitang Geratric Diseases Study were assessed for characteristics of tea consumption and cognitive function by administering questionnaires and the Abbreviated Mental Test (AMT), respectively. We divided the subjects into normal cognitive function group (AMT score ≥8) and CoI group (AMT score ≤7).   The association between tea consumption and risk of CoI was determined by logistic regression models. RESULTS: The least-squared means of the AMT scores for the subjects who seldom consumed tea were less favorable than those who habitually consumed tea. An inverse association was found between tea consumption (of any type) and prevalence of CoI (odds ratio = 0.74, 95% confidence interval = 0.57-0.98, P = 0.032). Interestingly, the protective correlation of tea was more obvious in never smokers (odds ratio = 0.63), but vanished in current/former smokers (odds ratio = 1.10). In never smokers, frequency of tea consumption was significantly associated with CoI (P for trend = 0.010). CONCLUSION: Habitual tea consumption is suggested to be associated with a decreased risk of CoI among elders in Suzhou, and a higher frequency of tea consumption was associated with a lower prevalence of CoI among never smokers.

Pharmacy students' use of and beliefs about traditional healthcare.

Health professional students come from many different cultural backgrounds, and may be users of traditional healthcare (also known as ethnomedicine or folk medicine). This study aimed to explore New Zealand pharmacy students' knowledge and beliefs about traditional healthcare, and to examine whether these changed during the course. A questionnaire was administered to students in 2011 and again in 2013. Students were from a wide range of ethnic groups. Their reported use of traditional healthcare increased (from 48% in 2011 to 61% in 2013) and was usually for minor illness or prevention. Non New Zealand European students were more likely to use traditional healthcare. Use of traditional healthcare was relatively common, and after exposure to a biomedical curriculum students seemed to be more, rather than less likely to report using traditional healthcare. Education about traditional healthcare should not be based on the assumption that all healthcare students are unfamiliar with, or non-users of, traditional healthcare.

OB-RL silencing inhibits the thermoregulatory ability of Great Roundleaf Bats (Hipposideros armiger).

Previous studies have shown that the hormone Leptin has an important role in mammalian heterothermy by regulating metabolism and food intake via lipolysis, as well as adaptive evolution of Leptin in heterothermic bats driven by selected pressure. However, the mechanism of Leptin in heterothermic regulation in mammals is unknown. By combining previous results, we speculated that the Leptin signaling pathway mediated by OB-RL (Leptin receptor long form) in the hypothalamus is important. OB-RL is one of the products of db gene and mainly distributed in the hypothalamus. In this study, we used OB-RL as a molecular marker, combining with the RNA interference technology and physiological/molecular analyses with Hipposideros armiger (a hibernating bat species) as an animal model, to explore the mechanism of Leptin in heterothermic regulation. Our data showed that all of four anti-OB-RL shRNA lentivirus significantly inhibited OB-RL expression (>90%), and the interference efficiency of PSC1742 lentivirus reached the highest value. In situ hybridization proved that PSC1742 lentivirus significantly decreased the OB-RL expression in the hypothalamus, especially in the ventromedial hypothalamic nucleus (VHM, 86.6%). Physiological analysis demonstrated that the thermoregulatory ability of bats (e.g., reducing core body temperature and heart rate) was significantly depressed after OB-RL silencing in the hypothalamus, and animals could not enter torpor state. Our study for the first time proved that the knock-down of OB-RL expression in hypothalamus inhibits heterothermic regulation of bats, and also provided the clues for further analyzing the mechanism of Leptin in the heterothermic regulation of mammals.

Homocysteine homeostasis and betaine-homocysteine S-methyltransferase expression in the brain of hibernating bats.

Elevated homocysteine is an important risk factor that increases cerebrovascular and neurodegenerative disease morbidity. In mammals, B vitamin supplementation can reduce homocysteine levels. Whether, and how, hibernating mammals, that essentially stop ingesting B vitamins, maintain homocysteine metabolism and avoid cerebrovascular impacts and neurodegeneration remain unclear. Here, we compare homocysteine levels in the brains of torpid bats, active bats and rats to identify the molecules involved in homocysteine homeostasis. We found that homocysteine does not elevate in torpid brains, despite declining vitamin B levels. At low levels of vitamin B6 and B12, we found no change in total expression level of the two main enzymes involved in homocysteine metabolism (methionine synthase and cystathionine ß-synthase), but a 1.85-fold increase in the expression of the coenzyme-independent betaine-homocysteine S-methyltransferase (BHMT). BHMT expression was observed in the amygdala of basal ganglia and the cerebral cortex where BHMT levels were clearly elevated during torpor. This is the first report of BHMT protein expression in the brain and suggests that BHMT modulates homocysteine in the brains of hibernating bats. BHMT may have a neuroprotective role in the brains of hibernating mammals and further research on this system could expand our biomedical understanding of certain cerebrovascular and neurodegenerative disease processes.

[Effect of electroacupuncture on lipid metabolism in male and female obesity rats].

OBJECTIVE: To investigate the influence of electroacupuncture (EA) on lipid metabolism in both sexes of obesity model rats. METHODS: A total of 30 male and 30 female SD rats were randomized into normal control, model and EA groups respectively, with 10 rats in each group. EA (2 Hz, 1-2 mA) was applied to the ipsilateral "Zusanli" (ST 36)-"Sanyin-jiao"(SP 6) and bilateral "Fenglong" (ST 40) for 30 min, once daily for 28 days. In addition,"Quchi" (LI 11),"Zhongwan" (CV 12) and "Guanyuan" (CV 4) were punctured with filiform needles and stimulated by manipulating the needle for 1 min, separately. Obesity model was duplicated by subcutaneous injection of 15% glutamic sodium (0.2 mL/10 g) once daily for 5 days and by feeding the animal with high fat forage for 36 days. Lee's index was calculated, and plasma triglyeride (TG) concentration detected by glycerol-phosphoric acid oxidase-peroxydase method, total cholesterol (TC) detected by cholesterol oxidase method, and plasma low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) contents were assayed by one-step method, respectively. RESULTS: In both male and female rats, compared to their own normal groups, the Lee's index, plasma TG, TC and LDL-C contents were increased significantly and plasma HDL-C contents decreased obviously in the model groups (P<0.01), while compared to their own model groups, the Lee's index, plasma TG, TC and LDL-C levels in the EA groups were down-regulated considerably and plasma HDL-C contents up-regulated remarkably after the treatment (P<0.01, P<0.05). The efficacies of the EA intervention were obviously better in reducing Lee's index for male rats, and in down-regulating plasma TG and TC contents in female rats (P<0.05). No significant differences were found between male and female rats in EA intervention for plasma LDL-C and HDL-C levels. CONCLUSION: EA intervention can effectively regulate obesity rats' Lee's index and plasma TG, TC, LDL-C and HDL-C levels. The effects are different in male and female rats.

Differential changes of regional cerebral blood flow in two bat species during induced hypothermia measured by perfusion-weighted magnetic resonance imaging.

Cerebral blood flow (CBF) of a vespertilionid bat, Miniopterus fuliginosus (M. f.), and a pteropodid bat, Rousettus leschenaultii (R. l.) was measured non-invasively during induced hypothermia (37-10°C for M. f. and 37-24°C for R. l.) with perfusion-weighted magnetic resonance imaging. In both species, the average CBF was found to decrease with rectal temperature. The patterns of hypothermia-induced regional CBF changes, however, were different between the two species. In the pteropodid bat, the extent of CBF decrease at lower rectal temperature was similar in the cortex and thalamus, resulting in an unchanged thalamus/cortex CBF ratio. In contrast, the thalamus/cortex CBF ratio in the vespertilionid species increased progressively with decreasing rectal temperature (1.52 ± 0.14 at 37 ± 1°C vs. 2.28 ± 0.29 at 10 ± 1°C). These results suggest that the manner in which the two bat species cope with low body temperature may be reflected by a differential CBF regulation between thalamus and cortex.

Molecular cloning and evolutionary analysis of the GJA1 (connexin43) gene from bats (Chiroptera).

Gap junction protein connexin43 (Cx43), encoded by the GJA1 gene, is the most abundant connexin in the cardiovascular system and was reported as a crucial factor maintaining cardiac electrical conduction, as well as having a very important function in facilitating the recycling of potassium ions from hair cells in the cochlea back into the cochlear endolymph during auditory transduction processes. In mammals, bats are the only taxon possessing powered flight, placing exceptional demand on many organismal processes. To meet the demands of flying, the hearts of bats show many specialties. Moreover, ultrasonic echolocation allows bat species to orientate and often detect and locate food in darkness. In this study, we cloned the full-length coding region of GJA1 gene from 12 different species of bats and obtained orthologous sequences from other mammals. We used the maximum likelihood method to analyse the evolution of GJA1 gene in mammals and the lineage of bats. Our results showed this gene is much conserved in mammals, as well as in bats' lineage. Compared with other mammals, we found one private amino acid substitution shared by bats, which is located on the inner loop domain, as well as some species-specific amino acid substitutions. The evolution rate analyses showed the signature of purifying selection on not only different classification level lineages but also the different domains and amino acid residue sites of this gene. Also, we suggested that GJA1 gene could be used as a good molecular marker to do the phylogenetic reconstruction.

Up-regulation of a non-kinase activity isoform of Ca(2+)/calmodulin-dependent protein kinase kinase beta1 (CaMKKbeta1) in hibernating bat brain.

Hibernation is an adaptive strategy that is utilized by some animals to survive the harsh environments of low temperature and food scarce. Hibernators, however, can survive in frequent and dramatic fluctuation of body temperature and blood flow causing by periodic arousals during hibernation without brain insult, and this indicates that it must have some unique adaptive aspects of hibernation physiology. To find out the up-regulated genes of bat brain during hibernation and explore the brain function adaptive mechanism of bat, the suppression subtractive hybridization (SSH) library was constructed from the brain tissue of greater horseshoe bats. Dot blot screening was carried out and the up-regulated genes in hibernating state were obtained. Then RT-PCR and RQ-PCR were performed to test the expression patterns of selected cDNAs. Here we first show that the functional and non-functional isoforms of bat CaMKKbeta1 display distinct expression patterns between hibernating and active states. The up-regulation of non-functional form of CaMKKbeta1 may represent a new neuroprotective strategy adopted by bats or even other hibernators to avoid the CNS damage during hibernation. Our results showed that bat CaMKKbeta1 gene has four transcript isoforms and these transcript variants differ primarily in exons b and d, which are 129 bp and 43 bp respectively. Statistical analyses indicated that these isoforms display distinct expression patterns at different states, in which only isoform 3, the non-functional form, increased 300% at hibernating state. These results suggest that distinct expression patterns of transcript isoforms of a gene, which have different activity, may represent a new potential adaptive mechanism in hibernation, except for the simple up-regulation of selected genes/proteins and the reversible protein phosphorylation.

TCM treatment for 63 cases of senile dyssomnia.

In order to study the therapeutic effects of the TCM drugs on senile dyssomnia, 121 such patients were randomly divided into a treatment group of 63 cases (given the TCM drugs) and a control group of 58 cases (given estazolam). The changes shown in the SDRS and HAMA scores and the other indexes were observed in both of the two groups to evaluate the therapeutic effects. The results showed that the effective rate was 76.3% in the treatment group, and it was 69.1% in the control group; and that the TCM drugs had better effects in improving such symptoms as lethargy, dry mouth, and rebound of insomnia. Therefore, it can be concluded that the effect of the TCM drugs isbetter for senile dyssomnia than that of the Western drug estazolam.

Evolution of nutrient structure and phytoplankton composition in the Jiaozhou Bay ecosystem.

The inventories of nutrients in the surface water and large phytoplankton( > 69 microm) were analyzed from the data set of JERS ecological database about a typical coastal waters, the Jiaozhou Bay, China, from 1960s for N, P and from 1980s for Si. By examining long-term changes of nutrient concentration, calculating stoichiometric balance, and comparing diatom composition, Si limitation of diatom production was found to be more possible. The possibility of Si limitation was from 37% in 1980s to 50% in 1990s. Jiaozhou Bay ecosystem is becoming serious eutrophication, with notable increase of NO2-N, NO3-N and NH4-N from 0.1417 micromol/L, 0.5414 micromol/L, 1.7222 micromol/L in 1960s to 0.9551 micromol/L, 3.001 micromol/L, 8.0359 micromol/L in late 1990s respectively and prominent decrease of Si from 4.2614 micromol/L in 1980s to 1.5861 micromol/L in late 1990s; the nutrient structure is controlled by nitrogen; the main limiting nutrient is probably silicon; because of the Si limitation the phytoplankton community structure has changed drastically.