Controllable liquid manipulation is of paramount scientific and technological importance in various fields,such as the chemical industry,biomedicine,and agricultural production.Magnetic actuation,characterized by rapi...Controllable liquid manipulation is of paramount scientific and technological importance in various fields,such as the chemical industry,biomedicine,and agricultural production.Magnetic actuation,characterized by rapid,contactless,and environmentally benign operation,has emerged as a promising approach for precise liquid control.However,conventional magnetic strategies typically govern droplet movement on open surfaces,facing limitations such as restricted liquid volumes,uncertain flow paths,and inevitable evaporation,thereby constraining their broader practical applications.Recently,a variety of magneticdriven strategies have been developed to dynamically regulate liquids within enclosed spaces,especially through physicochemical mechanisms.These approaches provide efficient control over liquid behavior by leveraging magnetically induced chemical changes,structural deformations,and dragging motions,opening new opportunities for flexible and versatile fluid management.This review explores the design and mechanisms of magneto-responsive confined interfaces for the manipulation of nonmagnetic liquids,highlighting key advancements and potential applications including liquid valves,liquid mixing,liquid flow regulation,and liquid pumping.Finally,the existing challenges and future prospects in this field are presented.展开更多
AIM: To investigate the role of TR3 in induction of apoptosis in gastric cancer cells. METHODS: Human gastric cancer cell line, MGC80-3, was used. Expression of TR3 mRNA and its protein was detected by Northern blot a...AIM: To investigate the role of TR3 in induction of apoptosis in gastric cancer cells. METHODS: Human gastric cancer cell line, MGC80-3, was used. Expression of TR3 mRNA and its protein was detected by Northern blot and Western blot. Localization of TR3 protein was showed by immunofluorescence analysis under laser-scanning confocal microscope. Apoptotic morphology was observed by DAPI fluorescence staining, and apoptotic index was counted among 1000 cells randomly. Stable transfection assay was carried out by Lipofectamine. RESULTS: Treatment of MGC80-3 cells with TPA and VP-16 resulted in apoptosis, accompanied by the repression of Bcl-2 protein in a time-dependent manner. At the same time, TPA and VP-16 also up-regulated expression level of TR3 mRNA in MGC80-3 cells that expressed TR3 mRNA. When antisense-TR3 expression vector was transfected into the cells, expression of TR3 protein was repressed. In this case, TPA and VP-16 did not induce apoptosis. In addition, TPA and VP-16-induced apoptosis involved in translocation of TR3. In MGC80-3 cells, TR3 localized concentrative in nucleus, after treatment of cells with TPA and VP-16, TR3 translocated from nucleus to cytosol obviously. However, when this nuclear translocation was blocked by LMB, apoptosis was not occurred in MGC80-3 cells even in the presence of TPA and VP-16. CONCLUSION: Induction of apoptosis by TPA and VP-16 is through induction of TR3 expression and translocation of TR3 from nucleus to cytosol, which may be a novel signal pathway for TR3, and represent the new biological function of TR3 to exert its effect on apoptosis in gastric cancer cells.展开更多
AIM: To investigate the expression of recombinant HBsAg (rHBsAg) in transgenic cherry tomatillo in order to explore the feasibility of producing HBV oral vaccine with cherry tomatillo by animal immune tests.METHODS: T...AIM: To investigate the expression of recombinant HBsAg (rHBsAg) in transgenic cherry tomatillo in order to explore the feasibility of producing HBV oral vaccine with cherry tomatillo by animal immune tests.METHODS: The recombinant plant expression vector containing HBsAg gene was constructed. Mediated with Agrobacterium tumefaciens, HBsAg gene was transferred into cotyledons of cherry tomatillo. Transformed cherry tomatillos were obtained through hygromycin delay-selection. Integrated DNA in transgenic cherry tomatillo was confirmed by hygromycin resistance selection, Gus detection, polymerase chain reaction (PCR) and dot blotting analysis. Antigenicity of rHBsAg was examined by ELISA and the immunogenicity of rHBsAg derived from transgenic cherry tomatillo tissues was confirmed by oral feed of transformed tissues to BALB/c mice primed with commercial HBV vaccines. Specific antibody titers in mice's serum were examined by ELISA every week.RESULTS: By far, 10 positive lines of transgenic cherry tomatillos containing HBsAg gene were obtained. Among different organs of the same transgenic cherry tomatillo,level of rHBsAg expressed in leaves was the highest with the yield up to 300ng/g fresh weight. And the rHBsAg expression level in fruits was about 10 ng/g fresh weight.In animal immune tests, oral delivery with transgenic tissues to mice primed with commercial vaccine instead of naive mice resulted in significant immune response.CONCLUSION: The result of this animal immune test indicated the rHBsAg derived from transgenic cherry tomatillo possessed normal immunogenicity. This work demonstrated the feasibility to generate oral immunogenic rHBsAg in transgenic cherry tomatillo, and would provide some experimental approach for the production of low-cost oral vaccines using transgenic cherry tomatillo in large scale.展开更多
AIM: To investigate the effects of tachyplesin on the cell cycle regulation in human hepatcarcinoma cells.METHODS: Effects of tachyplesin on the cell cycle in human hepatocarcinoma SMMC-7721 cells were assayed with fl...AIM: To investigate the effects of tachyplesin on the cell cycle regulation in human hepatcarcinoma cells.METHODS: Effects of tachyplesin on the cell cycle in human hepatocarcinoma SMMC-7721 cells were assayed with flow cytometry. The protein levels of p53, p16, cyclin D1 and CDK4 were assayed by immunocytochemistry. The mRNA levels of p21WAF1/CIP1 and c-myc genes were examined with in situ hybridization assay.RESULTS: After tachyplesin treatment, the cell cycle arrested at G0/G1 phase, the protein levels of mutant p53, cyclin D1 and CDK4 and the mRNA level of c-myc gene were decreased, whereas the levels of p16 protein and p21wWF1/CIP1 mRNA increased.CONCLUSION: Tachyplesin might arrest the cell at G0/G1 phase by upregulating the levels of p16 protein and p21WAF1/CIP1 mRNA and downregulating the levels of mutant p53, cyclin D1 and CDK4 proteins and c-myc mRNA, and induce the differentiation of human hepatocacinoma cells.展开更多
Influence of waterlogging time on the growth of Kandelia candel(L.) Druce seedlings grown for 70 d in the artificial- tidal tanks' simulated semidiurnal tide under greenhouse is studied. Sand and soil act as the s...Influence of waterlogging time on the growth of Kandelia candel(L.) Druce seedlings grown for 70 d in the artificial- tidal tanks' simulated semidiurnal tide under greenhouse is studied. Sand and soil act as the substrate and artificial seawater with salinity of 15 is used in cultivation. Shorter waterlogging time(inundated for about 2 ~ 4 h) promotes the growth of K. candel seedlings, while longer time(inundated more than 8 h) or no waterlogging(0 h) inhibits their growth. The number and length of aerating roots increase with the increase of waterlogging time. Under existing conditions, the optimal waterlogging time for the growth of K. candel seedlings is about 2 ~ 4 h in every tide cycle. Compared with other treatments, the 2 h sanded treatments obtain the highest biomass of seedlings, have the lowest mass loss of hypocotyl and broaden the photosynthetic area by increasing the area per leaf after 70-d cultivation. And the soil treatments have the similar tendency. However, waterlogging for 8 h in every tide cycle is critical for normal development of seedlings.K. candel seedlings are highly tolerant to waterlogging and a proper waterlogging is beneficial to the growth of K. candel seedlings.展开更多
Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtrop...Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtropical forests only were little known. The goal of this study is to measure the concentrations and monthly dynamics of DOC and DON in precipitation, throughfall and stemflow for two planta- tions of Schima superba (SS) and Chinese fir (Cunninghamia lanceolata, CF) in Jianou, Fujian, China. Samples of precipitation, throughfall and stemflow were collected on a rain event base from January 2002 to December 2002. Upon collection, all water samples were analyzed for DOC, NO3 -N, NH4 -N and total dissolved N (TDN). DON was calculated by subtracting NO3 -N and NH4 -N from TDN. The results - + - + showed that the precipitation had a mean DOC concentration of 1.7 mg·L-1 and DON concentration of 0.13 mg·L-1. The mean DOC and DON concentrations in throughfall were 11.2 and 0.24 mg·L-1 in the SS and 10.3 and 0.19 mg·L-1 in the CF respectively. Stemflow DOC and DON concentrations in the CF (19.1 and 0.66 mg·L-1 respectively) were significantly higher than those in the SS (17.6 and 0.48 mg·L-1 respectively). No clear monthly variation in precipitation DOC concentration was found in our study, while DON concentration in precipita- tion tended to be higher in summer or autumn. The monthly variations of DON concentrations were very similar in throughfall and stemflow at both forests, showing an increase at the beginning of the rainy season in March. In contrast, monthly changes of the DOC concentrations in throughfall of the SS and CF were different to those in stemflow. Throughfall DOC concentrations were higher from February to April, while relatively higher DOC concentrations in stemflow were found during September-November period.展开更多
Tumor growth without size restriction depends on vascular supply.The ability of tumor to induce new blood-vessel formation has been a major focus of cancer research over the past decade.It is now known that members of...Tumor growth without size restriction depends on vascular supply.The ability of tumor to induce new blood-vessel formation has been a major focus of cancer research over the past decade.It is now known that members of the vascular endothelial growth factor and angiopoietin families,mainly secreted by tumor cells, induce tumor angiogenesis,whereas other endogenous angiogenic inhibitors, including thrombospondin-1 and angiostatin, keep tumor in dormancy.Experimental and clinical evidence has suggested that the process of tumor metastasis depends on angiogenesis or lymphangiogenesis. This article summarizes the recent research progress for some basic pro- or anti-angiogenic factors in tumor angiogenesis.展开更多
A case study on the cyclonic eddy generated by the tropical cyclone looping over the northern South China Sea (NSCS) is presented, using TOPEX/POSEIDON altimeter data and AVHRR sea surface temperature (SST) data. Thre...A case study on the cyclonic eddy generated by the tropical cyclone looping over the northern South China Sea (NSCS) is presented, using TOPEX/POSEIDON altimeter data and AVHRR sea surface temperature (SST) data. Three cases relating to the tropical cyclone events (Typhoon Kai-Tak in July 2000, Tropical Storm Russ in June 1994 and Tropical Storm Maria in August-September 2000) over the NSCS have been analyzed. For each looping tropical cyclone case, the cyclonic eddy with an obvious sea level depression appears in the sea area where the tropical cyclone takes a loop form, and lasts for about 2 weeks with a slight variation in location. The cold core with the SST difference greater than 2℃against its surrounding areas is also observed by the satellite-derived SST data.展开更多
The genetic diversity and differentiation of 6 mud crab Scylla serrata populations from southeastern China are investigated using allozyme electrophoresis. The mean number of alleles per locus population is 1.3 ±...The genetic diversity and differentiation of 6 mud crab Scylla serrata populations from southeastern China are investigated using allozyme electrophoresis. The mean number of alleles per locus population is 1.3 ± 0.1; the percentage of polymorphic loci per population is 27.3; the observed heterozygosity ranges from (0.195±0.083) to ( 0.241±0.090) and the expected heterozygosity ranges from ( 0.105±0.043 ) to ( 0.131±0.047 ). The coefficient of gene differentiation among populations is low (Fst =0.032), indicating that only 3.2 % of the total genetic diversity comes from inter-population, while the remaining 96.8 % comes from intra-population differences. The genetic distance among populations is 0.000-0.008 (the average is 0.002). Gene flow among the populations is large (Nm = 7.56).Genetic structure is very similar among 6 Scylla serrata populations.展开更多
AIM: To transfer hepatitis E virus (HEV) ORF2 partial gene to tomato plants, to investigate its expression in transformants and the immunoactivity of expression products, and to explore the feasibility of developing a...AIM: To transfer hepatitis E virus (HEV) ORF2 partial gene to tomato plants, to investigate its expression in transformants and the immunoactivity of expression products, and to explore the feasibility of developing a new type of plantderived HEV oral vaccine.METHODS: Plant binary expression vector p1301E2,carrying a fragment of HEV open reading frame-2 (named HEV-E2), was constructed by linking the fragment to a constitutive CaMV35s promoter and nos terminator, then directly introduced into Agrobacterium tumefaciens EHA105. With leaf-disc method, tomato plants medicated by EHA105 were transformed and hygromycin-resistant plantlets were obtained in selective medium containing hygromycin. The presence and integration of foreign DNA in transgenic tomato genome were confirmed by Gus gene expression, PCR amplification and Southern dot blotting.The immunoactivity of recombinant protein extracted from transformed plants was examined by enzyme-linked immunosorbant assay (ELISA) using a monoclonal antibody specifically against HEV. ELISA was also used to estimate the recombinant protein content in leaves and fruits of the transformants.RESULTS: Seven positive lines of HEV-E2-transgenic tomato plants confirmed by PCR and Southern blotting were obtained and the immunoactivity of recombinant protein could be detected in extracts of transformants. The expression levels of recombinant protein were 61.22 ng/g fresh weight in fruits and 6.37-47.9 ng/g fresh weight in leaves of the transformants.CONCLUSION: HEV-E2 gene was correctly expressed in transgenic tomatoes and the recombinant antigen derived from them has normal immunoactivity. Transgenic tomatoes may hold a good promise for producing a new type of lowcost oral vaccine for hepatitis E virus.展开更多
The biomass, species composition and diversity of benthic diatom assemblages in mud-flat soils in Kandelia candel (L.) Druce communities with and without vegetation were studied seasonally at the Houyu Bay in Fuding C...The biomass, species composition and diversity of benthic diatom assemblages in mud-flat soils in Kandelia candel (L.) Druce communities with and without vegetation were studied seasonally at the Houyu Bay in Fuding City, Fujian Province, China. A total of 103 taxa were identified (including varieties). Eighty-four taxa were found in the mud-flat with vegetation and 74 taxa in the mud-flat without vegetation, while the biomass was large in January and April and decreased from July to October. The most abundant species in the mud-flat with vegetation are Nitzschia cocconeiformis, Gyrosigma scalproides and N. fasciculata, compared with G. scalproides and N. obtusa var. scalpelliformis in the mud-flat without vegetation. High H' values at 2 sites during all seasons suggest that diatom assemblages in the sediments of the Houyu Bay represent an original environment. Multi-dimensional scaling of diatom assemblages from mud-flats with and without vegetation shows that a slight seasonal change and only a single association occur in the mangroves.展开更多
The polycyclic aromatic hydrocarbons(PAHs) concentrations were determined in the root of three mangrove species(Kandelia candel, Avicennia marina and Bruguiera gymnorrhiza) and their growing environment(sediment) in m...The polycyclic aromatic hydrocarbons(PAHs) concentrations were determined in the root of three mangrove species(Kandelia candel, Avicennia marina and Bruguiera gymnorrhiza) and their growing environment(sediment) in mangrove wetlands of Jiulong River Estuary, Fujian, China. The total PAHs(16 parent PAHs) in mangrove sediments ranged from 193.44 to 270.53 ng/g dw, with a mean value of 231.76±31.78 ng/g dw. Compared with other mangrove and coastal marine sediments, the PAHs concentrations of all the sampling areas in this study were at relatively lower level. The total PAHs(13 parent PAHs) values varied from 30.83 to 62.73 ng/g dw in mangrove roots. Benzo[a]pyrene(five-ring), fluoranthene(four-ring) and pyrene(four-ring) dominated in mangrove sediments. Based on ratios of phenathrene/anthracene, fluoranthene/pyrene and fluoranthene/pyrene + fluoranthene, the main possible sources of surface sediment PAHs were identified as grass, wood or coal combustion for mangrove wetlands of Jiulong River Estuary. Naphthalene(two-ring) and phenathrene(three-ring) were the most abundant compounds in mangrove roots. Sediment-to-vegetation bioconcentration factors(BCF SV s) were calculated and their relationships with PAHs' physico-chemical properties were investigated. The average BCF SV s of PAHs for three mangrove species roots were almost all under the level of 1 except for naphthalene. Good linear relationship between BCF SV values for mangrove roots and PAHs water solubility, octanol-water partitioning coefficients was derived in present study. The solubility and the octanol-water partition coefficient were proved to be good predictors for the accumulation of PAHs in mangrove roots, respectively.展开更多
Intertidal zone is a significant wetland between land and ocean. It plays an important rolein maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are import...Intertidal zone is a significant wetland between land and ocean. It plays an important rolein maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are important 'refueling' point along the East Asian/Australian flyway of migratory birds. The environmental quality of Mai Po and Futian mudflats have aroused great concern due to rapid economic developments in Hong Kong and Shenzhen in recent decades. Macroinfauna of Mai Po and Futian mudflats was investigated in December 2000 and the faunal data were used to assess their environmental quality. Two other mudflats, namely Ma Wan Typhoon Shelter (a more disturbed area) and Luk Keng intertidal mudflat (a place with relatively less human disturbance), were also sampled for macroinfauna and used as reference mudflats. Shannon - Weaver species diversity index (Isd), biotic coefficient (Cb) and macrofaunal pollution index (Imp) of the macrofauna community on four intertidal mudflats were used to determine their environmental quality. The results showed that Luk Keng intertidal mudflat was unpolluted, Mai Po and Futian mudflats were slightly polluted, and Ma Wan was moderately polluted. The pollution in Ma Wan Typhoon Shelter mainly came from various types of rubbish and fishing boats that disturbed the sediment, while pollution sources in Mai Po and Futian mudflats were discharges of industrial water, municipal sewage and from nearby rivers.展开更多
Ecological security is a vital problem that people all over the world today have to face and solve, and the situation of ecological security is getting more and more severe and has begun to impede heavily the sustaina...Ecological security is a vital problem that people all over the world today have to face and solve, and the situation of ecological security is getting more and more severe and has begun to impede heavily the sustainable development of social economy. Ecological environment pre-warning has become a hotspot for the modern environment science. This paper introduces the theories of ecological security pre-warning and tries to constitute a pre-warning model of ecological security. In terms of pressure-state-response model, the pre-warning guide line of ecological security is constructed while the pre-warning degree judging model of ecological security is established based on fuzzy optimization. As a case, the model is used to assess the present condition pre-warning of the ecological security of Anhui Province. The result is in correspondence with the real condition: the ecological security situations of 8 cities are dangerous and 9 cities are secure. The result shows that this model is scientific and effective for regional ecological security pre-warning.展开更多
AIM: To investigate the modification of baculovirus vector and the feasibility of delivering exogenous genes into mammalian cells with the culture supernatant of Spodoptera frugiperta (Sf9) cells infected by recombina...AIM: To investigate the modification of baculovirus vector and the feasibility of delivering exogenous genes into mammalian cells with the culture supernatant of Spodoptera frugiperta (Sf9) cells infected by recombinant baculoviruses. METHODS: Two recombinant baculoviruses (BacV-CMV-EGFPA, BacV-CMV-EGFPB) containing CMV-EGFP expression cassette were constructed. HepG2 cells were directly incubated with the culture supernatant of Sf9 cells infected by recombinant baculoviruses, and reporter gene transfer and expression efficiencies were analyzed by flow cytometry (FCM). The optimal transduction conditions were investigated by FCM assay in HepG2 cells. Gene-transfer and expression efficiencies in HepG2 or CV1 cells by baculovirus vectors were compared with lipofectAMINE, recombinant retrovirus and vaccinia virus expression systems. Twenty different mammalian cell lines were used to investigate the feasibility of delivering exogenous genes into different mammalian cells with the culture supernatant of infected Sf9 cells. RESULTS: CMV promoter could directly express reporter genes in Sf9 cells with a relatively low efficiency. Target cells incubated with the 1:1 diluted culture supernatant (moi=50) for 12 h at 37 ℃ could achieve the highest transduction and expression efficiencies with least impairment to cell viability. Under similar conditions the baculovirus vector could achieve the highest gene-transfer and expression efficiency than lipofectAMINE, recombinant retrovirus and vaccinia virus expression systems. Most mammalian cell lines could be transduced with recombinant baculovirus. In primate adherent culture cells the recombinant baculovirus could arrive the highest infection and expression efficiencies, but it was not very satisfactory in the cell lines from mice and suspended culture cells. CONCLUSION: Mammalian cells incubated with the culture supernatant of infected Sf9 cells could serve as a very convenient way for rapid and efficient expression of foreign genes in mammalian cells, but it might be more suitable for primate adherent culture cells.展开更多
Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands are...Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands area in the South China Sea. Averaged over the whole investigation area, depth-weighted integrated cell abundance (DWA) of Syn, Pro, Euk and Bact was 1.6 (0.4-5.7)×103, 5.4 (0.1-7.3)×104, 0.7 (0.2-2.2)×103, and 2.3 (1.4-3.2)×105 cells/mL respectively. Picoautotrophic cell abundance was low in the northwest part of the Nansha Islands where surface water temperature was low and the upper mixed layer was shallow. Concurrently, a surface maximum vertical distribution pattern was observed in this area. While in the southeast and east zones where temperatures were relatively higher and nitraclines were deeper, picoplankton is abundant and a subsurface maximum around 50-75 m is observed. Coupling of horizontal and vertical distribution patterns of picoplankton abundance and hydrological status was found, suggesting a strong influence of currents and water column structure on picoplankton distribution in the investigation area. Contrary to that in the shelf water in the East China Sea, the relationship between Pro and Bact in the Nansha Islands area in the South China Sea was not significantly negative but weakly positive. Moreover, a similar distribution pattern of Syn and Pro was observed. Possible reasons for these differences in the two marine regimes were discussed.展开更多
Oxidation of cyclohexene under 1 atmospheric pressure of molecular oxygen at 70C in the absence of solvent catalyzed by PAMAM-SA-M (Where PAMAM = polyamidoamine; SA = salicyaldehyde; M = metal ions Fe3+, Co2+, Ni2+, M...Oxidation of cyclohexene under 1 atmospheric pressure of molecular oxygen at 70C in the absence of solvent catalyzed by PAMAM-SA-M (Where PAMAM = polyamidoamine; SA = salicyaldehyde; M = metal ions Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Zn2+, respectively) dendrimers, afforded 2-cyclohexen-1-ol 1, 2-cyclohexen-1-one 2, 7-oxabicyclo [4,1,0] heptane 3 and 7-oxabicyl [4,1,0] heptan-2-one 4 as the major products. The factors that affect this reaction are also discussed.展开更多
Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment of nauplii to the water column population. The distribution and abundance of viable resting eggs of Acartia...Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment of nauplii to the water column population. The distribution and abundance of viable resting eggs of Acartia pacifica in the Xiamen Bay were determined by the presence of nauplii in the laboratory. The number of viable eggs var/ed temporally and spatially. The maximum number (9.2×10^4m^-2) of viable eggs was in summer. In spring the average abundance of viable eggs was 5.6×10^4 m^-2. The abundances of viable eggs in fall and winter were similar, respectively 2.7×10^4 and 3.3×10^4m^-2, which were the lowest in the year. The numbers of viable eggs inside the stations of the Xiamen Bay were higher than those outside the stations. The viable eggs were found at all depths (0-10 cm),although not in every station. The maximum number did not necessarily occur in the uppermost centimeter of the sediments but often occurred several centimeters below the water-sediment interface. The accumulation of viable eggs in the seabed of a subtropical bay constitutes a potential source of recruitment of nauplii into the pelagic population.展开更多
A survey was carried out in the central and north part of the Huanghai Sea (34.5° -37.0°N, 120.5°-124.0°E) during June 12-27, 2000. It was found that the abundance of marine flagellate ranged from ...A survey was carried out in the central and north part of the Huanghai Sea (34.5° -37.0°N, 120.5°-124.0°E) during June 12-27, 2000. It was found that the abundance of marine flagellate ranged from 45 to 1 278 cell/ml, 479 cell/ml in average. Flagellate was more abundant in the central part than in the north part of Huanghai Sea, and the abundance decreased with the increasing distance from the coast, showing a similar distribution pattern with isotherm. Vertically, high density of flagellate was always presented in the bottom of thermocline, and formed a dense accumulation in the central area of the Huanghai Sea Cold Water Mass. The effects of physical and biological factors on the distribution of marine flagellate in early summer were discussed. Water temperature (especially the existence of thermocline) rather than salinity showed significant effect on the distribution pattern of marine flagellate in the Huanghai Sea in early summer. When comparing the abundance of marine flagellate with that of other microorganisms, it revealed a comparatively stable relationship among these organ-hisms, with a ratio of heterotrophic bacteria: cyanobacteria: flagellate: dinoflagellate: ciliate being 105 :103:102:101:100.展开更多
The inventories of nutrients in the surface water and large phytoplankton(>69 μm) were analyzed from the data set of JERS ecological database about a typical coastal waters, the Jiaozhou Bay, China, from 1960s for...The inventories of nutrients in the surface water and large phytoplankton(>69 μm) 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 NO 2 N, NO 3 N and NH 4 N from 0 1417 μmol/L, 0 5414 μmol/L, 1 7222 μmol/L in 1960s to 0 9551 μmol/L, 3 001 μmol/L, 8 0359 μmol/L in late 1990s respectively and prominent decrease of Si from 4 2614 μmol/L in 1980s to 1 5861 μmol/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.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52025132,U24A20205,52303373,21621091,22021001,and 22121001)the China Postdoctoral Science Foundation(No.2024M763174)+2 种基金the 111 Project(Nos.B17027,B16029)the Natural Science Foundation of Fujian Province of China(No.2022J02059)the New Cornerstone Science Foundation through the Xplorer Prize。
文摘Controllable liquid manipulation is of paramount scientific and technological importance in various fields,such as the chemical industry,biomedicine,and agricultural production.Magnetic actuation,characterized by rapid,contactless,and environmentally benign operation,has emerged as a promising approach for precise liquid control.However,conventional magnetic strategies typically govern droplet movement on open surfaces,facing limitations such as restricted liquid volumes,uncertain flow paths,and inevitable evaporation,thereby constraining their broader practical applications.Recently,a variety of magneticdriven strategies have been developed to dynamically regulate liquids within enclosed spaces,especially through physicochemical mechanisms.These approaches provide efficient control over liquid behavior by leveraging magnetically induced chemical changes,structural deformations,and dragging motions,opening new opportunities for flexible and versatile fluid management.This review explores the design and mechanisms of magneto-responsive confined interfaces for the manipulation of nonmagnetic liquids,highlighting key advancements and potential applications including liquid valves,liquid mixing,liquid flow regulation,and liquid pumping.Finally,the existing challenges and future prospects in this field are presented.
基金the National Outstanding Youth Science foundation of China (B type,39825502)the National Natural Science Foundation of China (39880015,30170477)the Natural Science Foundation of Fujian Province (C0110004).
文摘AIM: To investigate the role of TR3 in induction of apoptosis in gastric cancer cells. METHODS: Human gastric cancer cell line, MGC80-3, was used. Expression of TR3 mRNA and its protein was detected by Northern blot and Western blot. Localization of TR3 protein was showed by immunofluorescence analysis under laser-scanning confocal microscope. Apoptotic morphology was observed by DAPI fluorescence staining, and apoptotic index was counted among 1000 cells randomly. Stable transfection assay was carried out by Lipofectamine. RESULTS: Treatment of MGC80-3 cells with TPA and VP-16 resulted in apoptosis, accompanied by the repression of Bcl-2 protein in a time-dependent manner. At the same time, TPA and VP-16 also up-regulated expression level of TR3 mRNA in MGC80-3 cells that expressed TR3 mRNA. When antisense-TR3 expression vector was transfected into the cells, expression of TR3 protein was repressed. In this case, TPA and VP-16 did not induce apoptosis. In addition, TPA and VP-16-induced apoptosis involved in translocation of TR3. In MGC80-3 cells, TR3 localized concentrative in nucleus, after treatment of cells with TPA and VP-16, TR3 translocated from nucleus to cytosol obviously. However, when this nuclear translocation was blocked by LMB, apoptosis was not occurred in MGC80-3 cells even in the presence of TPA and VP-16. CONCLUSION: Induction of apoptosis by TPA and VP-16 is through induction of TR3 expression and translocation of TR3 from nucleus to cytosol, which may be a novel signal pathway for TR3, and represent the new biological function of TR3 to exert its effect on apoptosis in gastric cancer cells.
基金the grant from Natural Scientific Fundation of Fujian Province,No.C9910004Xiamen Kaili Biologic Product Limited Company
文摘AIM: To investigate the expression of recombinant HBsAg (rHBsAg) in transgenic cherry tomatillo in order to explore the feasibility of producing HBV oral vaccine with cherry tomatillo by animal immune tests.METHODS: The recombinant plant expression vector containing HBsAg gene was constructed. Mediated with Agrobacterium tumefaciens, HBsAg gene was transferred into cotyledons of cherry tomatillo. Transformed cherry tomatillos were obtained through hygromycin delay-selection. Integrated DNA in transgenic cherry tomatillo was confirmed by hygromycin resistance selection, Gus detection, polymerase chain reaction (PCR) and dot blotting analysis. Antigenicity of rHBsAg was examined by ELISA and the immunogenicity of rHBsAg derived from transgenic cherry tomatillo tissues was confirmed by oral feed of transformed tissues to BALB/c mice primed with commercial HBV vaccines. Specific antibody titers in mice's serum were examined by ELISA every week.RESULTS: By far, 10 positive lines of transgenic cherry tomatillos containing HBsAg gene were obtained. Among different organs of the same transgenic cherry tomatillo,level of rHBsAg expressed in leaves was the highest with the yield up to 300ng/g fresh weight. And the rHBsAg expression level in fruits was about 10 ng/g fresh weight.In animal immune tests, oral delivery with transgenic tissues to mice primed with commercial vaccine instead of naive mice resulted in significant immune response.CONCLUSION: The result of this animal immune test indicated the rHBsAg derived from transgenic cherry tomatillo possessed normal immunogenicity. This work demonstrated the feasibility to generate oral immunogenic rHBsAg in transgenic cherry tomatillo, and would provide some experimental approach for the production of low-cost oral vaccines using transgenic cherry tomatillo in large scale.
基金the National Natural Science Foundation of China,No.30170724
文摘AIM: To investigate the effects of tachyplesin on the cell cycle regulation in human hepatcarcinoma cells.METHODS: Effects of tachyplesin on the cell cycle in human hepatocarcinoma SMMC-7721 cells were assayed with flow cytometry. The protein levels of p53, p16, cyclin D1 and CDK4 were assayed by immunocytochemistry. The mRNA levels of p21WAF1/CIP1 and c-myc genes were examined with in situ hybridization assay.RESULTS: After tachyplesin treatment, the cell cycle arrested at G0/G1 phase, the protein levels of mutant p53, cyclin D1 and CDK4 and the mRNA level of c-myc gene were decreased, whereas the levels of p16 protein and p21wWF1/CIP1 mRNA increased.CONCLUSION: Tachyplesin might arrest the cell at G0/G1 phase by upregulating the levels of p16 protein and p21WAF1/CIP1 mRNA and downregulating the levels of mutant p53, cyclin D1 and CDK4 proteins and c-myc mRNA, and induce the differentiation of human hepatocacinoma cells.
文摘Influence of waterlogging time on the growth of Kandelia candel(L.) Druce seedlings grown for 70 d in the artificial- tidal tanks' simulated semidiurnal tide under greenhouse is studied. Sand and soil act as the substrate and artificial seawater with salinity of 15 is used in cultivation. Shorter waterlogging time(inundated for about 2 ~ 4 h) promotes the growth of K. candel seedlings, while longer time(inundated more than 8 h) or no waterlogging(0 h) inhibits their growth. The number and length of aerating roots increase with the increase of waterlogging time. Under existing conditions, the optimal waterlogging time for the growth of K. candel seedlings is about 2 ~ 4 h in every tide cycle. Compared with other treatments, the 2 h sanded treatments obtain the highest biomass of seedlings, have the lowest mass loss of hypocotyl and broaden the photosynthetic area by increasing the area per leaf after 70-d cultivation. And the soil treatments have the similar tendency. However, waterlogging for 8 h in every tide cycle is critical for normal development of seedlings.K. candel seedlings are highly tolerant to waterlogging and a proper waterlogging is beneficial to the growth of K. candel seedlings.
文摘Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtropical forests only were little known. The goal of this study is to measure the concentrations and monthly dynamics of DOC and DON in precipitation, throughfall and stemflow for two planta- tions of Schima superba (SS) and Chinese fir (Cunninghamia lanceolata, CF) in Jianou, Fujian, China. Samples of precipitation, throughfall and stemflow were collected on a rain event base from January 2002 to December 2002. Upon collection, all water samples were analyzed for DOC, NO3 -N, NH4 -N and total dissolved N (TDN). DON was calculated by subtracting NO3 -N and NH4 -N from TDN. The results - + - + showed that the precipitation had a mean DOC concentration of 1.7 mg·L-1 and DON concentration of 0.13 mg·L-1. The mean DOC and DON concentrations in throughfall were 11.2 and 0.24 mg·L-1 in the SS and 10.3 and 0.19 mg·L-1 in the CF respectively. Stemflow DOC and DON concentrations in the CF (19.1 and 0.66 mg·L-1 respectively) were significantly higher than those in the SS (17.6 and 0.48 mg·L-1 respectively). No clear monthly variation in precipitation DOC concentration was found in our study, while DON concentration in precipita- tion tended to be higher in summer or autumn. The monthly variations of DON concentrations were very similar in throughfall and stemflow at both forests, showing an increase at the beginning of the rainy season in March. In contrast, monthly changes of the DOC concentrations in throughfall of the SS and CF were different to those in stemflow. Throughfall DOC concentrations were higher from February to April, while relatively higher DOC concentrations in stemflow were found during September-November period.
基金Supported by the National Natural Science Foundation of China,No.30170463
文摘Tumor growth without size restriction depends on vascular supply.The ability of tumor to induce new blood-vessel formation has been a major focus of cancer research over the past decade.It is now known that members of the vascular endothelial growth factor and angiopoietin families,mainly secreted by tumor cells, induce tumor angiogenesis,whereas other endogenous angiogenic inhibitors, including thrombospondin-1 and angiostatin, keep tumor in dormancy.Experimental and clinical evidence has suggested that the process of tumor metastasis depends on angiogenesis or lymphangiogenesis. This article summarizes the recent research progress for some basic pro- or anti-angiogenic factors in tumor angiogenesis.
文摘A case study on the cyclonic eddy generated by the tropical cyclone looping over the northern South China Sea (NSCS) is presented, using TOPEX/POSEIDON altimeter data and AVHRR sea surface temperature (SST) data. Three cases relating to the tropical cyclone events (Typhoon Kai-Tak in July 2000, Tropical Storm Russ in June 1994 and Tropical Storm Maria in August-September 2000) over the NSCS have been analyzed. For each looping tropical cyclone case, the cyclonic eddy with an obvious sea level depression appears in the sea area where the tropical cyclone takes a loop form, and lasts for about 2 weeks with a slight variation in location. The cold core with the SST difference greater than 2℃against its surrounding areas is also observed by the satellite-derived SST data.
基金This study was supported by the National Natural Science Foundation of China under contract No.40376044Marine“863"Item of China under contract No.2002AA603013Foundation of Jimei University.
文摘The genetic diversity and differentiation of 6 mud crab Scylla serrata populations from southeastern China are investigated using allozyme electrophoresis. The mean number of alleles per locus population is 1.3 ± 0.1; the percentage of polymorphic loci per population is 27.3; the observed heterozygosity ranges from (0.195±0.083) to ( 0.241±0.090) and the expected heterozygosity ranges from ( 0.105±0.043 ) to ( 0.131±0.047 ). The coefficient of gene differentiation among populations is low (Fst =0.032), indicating that only 3.2 % of the total genetic diversity comes from inter-population, while the remaining 96.8 % comes from intra-population differences. The genetic distance among populations is 0.000-0.008 (the average is 0.002). Gene flow among the populations is large (Nm = 7.56).Genetic structure is very similar among 6 Scylla serrata populations.
基金a grant from the Natural Science Foundation of Fujian Province,No.C9910004Xiamen Kaili Biologic Product Limited Company
文摘AIM: To transfer hepatitis E virus (HEV) ORF2 partial gene to tomato plants, to investigate its expression in transformants and the immunoactivity of expression products, and to explore the feasibility of developing a new type of plantderived HEV oral vaccine.METHODS: Plant binary expression vector p1301E2,carrying a fragment of HEV open reading frame-2 (named HEV-E2), was constructed by linking the fragment to a constitutive CaMV35s promoter and nos terminator, then directly introduced into Agrobacterium tumefaciens EHA105. With leaf-disc method, tomato plants medicated by EHA105 were transformed and hygromycin-resistant plantlets were obtained in selective medium containing hygromycin. The presence and integration of foreign DNA in transgenic tomato genome were confirmed by Gus gene expression, PCR amplification and Southern dot blotting.The immunoactivity of recombinant protein extracted from transformed plants was examined by enzyme-linked immunosorbant assay (ELISA) using a monoclonal antibody specifically against HEV. ELISA was also used to estimate the recombinant protein content in leaves and fruits of the transformants.RESULTS: Seven positive lines of HEV-E2-transgenic tomato plants confirmed by PCR and Southern blotting were obtained and the immunoactivity of recombinant protein could be detected in extracts of transformants. The expression levels of recombinant protein were 61.22 ng/g fresh weight in fruits and 6.37-47.9 ng/g fresh weight in leaves of the transformants.CONCLUSION: HEV-E2 gene was correctly expressed in transgenic tomatoes and the recombinant antigen derived from them has normal immunoactivity. Transgenic tomatoes may hold a good promise for producing a new type of lowcost oral vaccine for hepatitis E virus.
基金supported by National Nature Science Fundation under contract No.30270118Fujian Nature Science Fundation under contract No.D210003Project of innovation foundation of Xiamen University under contract No XDKJCX0041018.
文摘The biomass, species composition and diversity of benthic diatom assemblages in mud-flat soils in Kandelia candel (L.) Druce communities with and without vegetation were studied seasonally at the Houyu Bay in Fuding City, Fujian Province, China. A total of 103 taxa were identified (including varieties). Eighty-four taxa were found in the mud-flat with vegetation and 74 taxa in the mud-flat without vegetation, while the biomass was large in January and April and decreased from July to October. The most abundant species in the mud-flat with vegetation are Nitzschia cocconeiformis, Gyrosigma scalproides and N. fasciculata, compared with G. scalproides and N. obtusa var. scalpelliformis in the mud-flat without vegetation. High H' values at 2 sites during all seasons suggest that diatom assemblages in the sediments of the Houyu Bay represent an original environment. Multi-dimensional scaling of diatom assemblages from mud-flats with and without vegetation shows that a slight seasonal change and only a single association occur in the mangroves.
文摘The polycyclic aromatic hydrocarbons(PAHs) concentrations were determined in the root of three mangrove species(Kandelia candel, Avicennia marina and Bruguiera gymnorrhiza) and their growing environment(sediment) in mangrove wetlands of Jiulong River Estuary, Fujian, China. The total PAHs(16 parent PAHs) in mangrove sediments ranged from 193.44 to 270.53 ng/g dw, with a mean value of 231.76±31.78 ng/g dw. Compared with other mangrove and coastal marine sediments, the PAHs concentrations of all the sampling areas in this study were at relatively lower level. The total PAHs(13 parent PAHs) values varied from 30.83 to 62.73 ng/g dw in mangrove roots. Benzo[a]pyrene(five-ring), fluoranthene(four-ring) and pyrene(four-ring) dominated in mangrove sediments. Based on ratios of phenathrene/anthracene, fluoranthene/pyrene and fluoranthene/pyrene + fluoranthene, the main possible sources of surface sediment PAHs were identified as grass, wood or coal combustion for mangrove wetlands of Jiulong River Estuary. Naphthalene(two-ring) and phenathrene(three-ring) were the most abundant compounds in mangrove roots. Sediment-to-vegetation bioconcentration factors(BCF SV s) were calculated and their relationships with PAHs' physico-chemical properties were investigated. The average BCF SV s of PAHs for three mangrove species roots were almost all under the level of 1 except for naphthalene. Good linear relationship between BCF SV values for mangrove roots and PAHs water solubility, octanol-water partitioning coefficients was derived in present study. The solubility and the octanol-water partition coefficient were proved to be good predictors for the accumulation of PAHs in mangrove roots, respectively.
文摘Intertidal zone is a significant wetland between land and ocean. It plays an important rolein maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are important 'refueling' point along the East Asian/Australian flyway of migratory birds. The environmental quality of Mai Po and Futian mudflats have aroused great concern due to rapid economic developments in Hong Kong and Shenzhen in recent decades. Macroinfauna of Mai Po and Futian mudflats was investigated in December 2000 and the faunal data were used to assess their environmental quality. Two other mudflats, namely Ma Wan Typhoon Shelter (a more disturbed area) and Luk Keng intertidal mudflat (a place with relatively less human disturbance), were also sampled for macroinfauna and used as reference mudflats. Shannon - Weaver species diversity index (Isd), biotic coefficient (Cb) and macrofaunal pollution index (Imp) of the macrofauna community on four intertidal mudflats were used to determine their environmental quality. The results showed that Luk Keng intertidal mudflat was unpolluted, Mai Po and Futian mudflats were slightly polluted, and Ma Wan was moderately polluted. The pollution in Ma Wan Typhoon Shelter mainly came from various types of rubbish and fishing boats that disturbed the sediment, while pollution sources in Mai Po and Futian mudflats were discharges of industrial water, municipal sewage and from nearby rivers.
基金Undertheauspicesof China Postdoctoral Science Foundation (No.2004035175), and the Natural Science Founda-tionof Anhui Provincial Bureau of Education (No.2003KJ043ZD)
文摘Ecological security is a vital problem that people all over the world today have to face and solve, and the situation of ecological security is getting more and more severe and has begun to impede heavily the sustainable development of social economy. Ecological environment pre-warning has become a hotspot for the modern environment science. This paper introduces the theories of ecological security pre-warning and tries to constitute a pre-warning model of ecological security. In terms of pressure-state-response model, the pre-warning guide line of ecological security is constructed while the pre-warning degree judging model of ecological security is established based on fuzzy optimization. As a case, the model is used to assess the present condition pre-warning of the ecological security of Anhui Province. The result is in correspondence with the real condition: the ecological security situations of 8 cities are dangerous and 9 cities are secure. The result shows that this model is scientific and effective for regional ecological security pre-warning.
基金Supported by the grant from 863 Program,No.2001AA628120
文摘AIM: To investigate the modification of baculovirus vector and the feasibility of delivering exogenous genes into mammalian cells with the culture supernatant of Spodoptera frugiperta (Sf9) cells infected by recombinant baculoviruses. METHODS: Two recombinant baculoviruses (BacV-CMV-EGFPA, BacV-CMV-EGFPB) containing CMV-EGFP expression cassette were constructed. HepG2 cells were directly incubated with the culture supernatant of Sf9 cells infected by recombinant baculoviruses, and reporter gene transfer and expression efficiencies were analyzed by flow cytometry (FCM). The optimal transduction conditions were investigated by FCM assay in HepG2 cells. Gene-transfer and expression efficiencies in HepG2 or CV1 cells by baculovirus vectors were compared with lipofectAMINE, recombinant retrovirus and vaccinia virus expression systems. Twenty different mammalian cell lines were used to investigate the feasibility of delivering exogenous genes into different mammalian cells with the culture supernatant of infected Sf9 cells. RESULTS: CMV promoter could directly express reporter genes in Sf9 cells with a relatively low efficiency. Target cells incubated with the 1:1 diluted culture supernatant (moi=50) for 12 h at 37 ℃ could achieve the highest transduction and expression efficiencies with least impairment to cell viability. Under similar conditions the baculovirus vector could achieve the highest gene-transfer and expression efficiency than lipofectAMINE, recombinant retrovirus and vaccinia virus expression systems. Most mammalian cell lines could be transduced with recombinant baculovirus. In primate adherent culture cells the recombinant baculovirus could arrive the highest infection and expression efficiencies, but it was not very satisfactory in the cell lines from mice and suspended culture cells. CONCLUSION: Mammalian cells incubated with the culture supernatant of infected Sf9 cells could serve as a very convenient way for rapid and efficient expression of foreign genes in mammalian cells, but it might be more suitable for primate adherent culture cells.
文摘Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands area in the South China Sea. Averaged over the whole investigation area, depth-weighted integrated cell abundance (DWA) of Syn, Pro, Euk and Bact was 1.6 (0.4-5.7)×103, 5.4 (0.1-7.3)×104, 0.7 (0.2-2.2)×103, and 2.3 (1.4-3.2)×105 cells/mL respectively. Picoautotrophic cell abundance was low in the northwest part of the Nansha Islands where surface water temperature was low and the upper mixed layer was shallow. Concurrently, a surface maximum vertical distribution pattern was observed in this area. While in the southeast and east zones where temperatures were relatively higher and nitraclines were deeper, picoplankton is abundant and a subsurface maximum around 50-75 m is observed. Coupling of horizontal and vertical distribution patterns of picoplankton abundance and hydrological status was found, suggesting a strong influence of currents and water column structure on picoplankton distribution in the investigation area. Contrary to that in the shelf water in the East China Sea, the relationship between Pro and Bact in the Nansha Islands area in the South China Sea was not significantly negative but weakly positive. Moreover, a similar distribution pattern of Syn and Pro was observed. Possible reasons for these differences in the two marine regimes were discussed.
文摘Oxidation of cyclohexene under 1 atmospheric pressure of molecular oxygen at 70C in the absence of solvent catalyzed by PAMAM-SA-M (Where PAMAM = polyamidoamine; SA = salicyaldehyde; M = metal ions Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Zn2+, respectively) dendrimers, afforded 2-cyclohexen-1-ol 1, 2-cyclohexen-1-one 2, 7-oxabicyclo [4,1,0] heptane 3 and 7-oxabicyl [4,1,0] heptan-2-one 4 as the major products. The factors that affect this reaction are also discussed.
文摘Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment of nauplii to the water column population. The distribution and abundance of viable resting eggs of Acartia pacifica in the Xiamen Bay were determined by the presence of nauplii in the laboratory. The number of viable eggs var/ed temporally and spatially. The maximum number (9.2×10^4m^-2) of viable eggs was in summer. In spring the average abundance of viable eggs was 5.6×10^4 m^-2. The abundances of viable eggs in fall and winter were similar, respectively 2.7×10^4 and 3.3×10^4m^-2, which were the lowest in the year. The numbers of viable eggs inside the stations of the Xiamen Bay were higher than those outside the stations. The viable eggs were found at all depths (0-10 cm),although not in every station. The maximum number did not necessarily occur in the uppermost centimeter of the sediments but often occurred several centimeters below the water-sediment interface. The accumulation of viable eggs in the seabed of a subtropical bay constitutes a potential source of recruitment of nauplii into the pelagic population.
文摘A survey was carried out in the central and north part of the Huanghai Sea (34.5° -37.0°N, 120.5°-124.0°E) during June 12-27, 2000. It was found that the abundance of marine flagellate ranged from 45 to 1 278 cell/ml, 479 cell/ml in average. Flagellate was more abundant in the central part than in the north part of Huanghai Sea, and the abundance decreased with the increasing distance from the coast, showing a similar distribution pattern with isotherm. Vertically, high density of flagellate was always presented in the bottom of thermocline, and formed a dense accumulation in the central area of the Huanghai Sea Cold Water Mass. The effects of physical and biological factors on the distribution of marine flagellate in early summer were discussed. Water temperature (especially the existence of thermocline) rather than salinity showed significant effect on the distribution pattern of marine flagellate in the Huanghai Sea in early summer. When comparing the abundance of marine flagellate with that of other microorganisms, it revealed a comparatively stable relationship among these organ-hisms, with a ratio of heterotrophic bacteria: cyanobacteria: flagellate: dinoflagellate: ciliate being 105 :103:102:101:100.
文摘The inventories of nutrients in the surface water and large phytoplankton(>69 μm) 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 NO 2 N, NO 3 N and NH 4 N from 0 1417 μmol/L, 0 5414 μmol/L, 1 7222 μmol/L in 1960s to 0 9551 μmol/L, 3 001 μmol/L, 8 0359 μmol/L in late 1990s respectively and prominent decrease of Si from 4 2614 μmol/L in 1980s to 1 5861 μmol/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.
