[Studies on micelle behaviors of sophorolipid biosurfactant by steady-state fluorescence probe method].

The critical micelle concentration (CMC) of sophorolipid was determined by steady-state fluorescence probe method in which pyrene was used as fluorescence probe. Meanwhile, the changes in the sophorolipid CMC were examined in the addition of NaCl and aliphatic alcohol, respectively. The results showed that the CMC of sophorolipid was 1.3 x 10(-4) mol x L(-1) and had a slight decrease as NaCl concentration increased. However, the CMC of sophorolipid appeared to increase in the presence of aliphatic alcohol. The aggregation numbers and the micelle size of sophorolipid solution were investigated by fluorescence quenching and laser light scattering method. The aggregation numbers were 4-8 with the concentrations of sophorolipid in the range of 4 -8 CMC and the micelle mean diameter for sophorolipid with the concentration of 6 CMC was about 90 nm. These experimental results indicated that the micelle should be incompact.

[Research on the 3D discrete fluorescence spectrum technique for differentiation of phytoplankton population].

The present research was targeted to develop a fluorescence analyser for phytoplankton population which uses a series of LEDs as the light source. So the 3D discrete fluorescence spectra with 12 excitation wavelengths (400, 430, 450, 460,470, 490, 500, 510, 525, 550, 570 and 590 nm) were determined by fluorescence spectrophotometer for 43 phytoplankton species. Then, the wavelet, Daubechies-7 (Db7), and Bayes Classifier were applied to extract the characteristics for each classes from the 3D discrete fluorescence spectra. Lastly, the fluorescence differentiation method for phytoplankton populations was established by multivariate linear regression and non-negative least squares, which could differentiate phytoplankton populations at the levels of both divisions and genus. This method was tested: for simulatively mixed samples(the dominant species accounted for 70%, 80%, 90% and 100% of the gross biomass, respectively) from 32 red tide algal species, and the correct discrimination rates at the level of genus were 67.5%, 75.8%, 81.4% and 79.4%, respectively. For simulatively mixed samples (the dominant divisions algae accounted for 50%, 75% and 100% of the gross biomass, respectively) from 43 algal species, the discrimination rates at the level of division were 95.2%, 99.7% and 91.9% with average relative content of 38.1%, 63.2% and 90.5%, respectively.

[Research on the 3D fluorescence spectra differentiation of phytoplankton by coiflet2 wavelet].

In the present paper, the authors utilize the wavelet base function coiflet2 (coif2) to analyze the 3D fluorescence spectra of 37 phytoplankton species belonging to 30 genera of 7 divisions, and these phytoplankton species include common species frequently causing harmful algal blooms and most predominant algal species in the inshore area of China Sea. After the Rayleigh and Raman scattering peaks were removed by the Delaunay triangulation interpolation, the fluorescence spectra of those phytoplankton species were transformed with the coiflet2 wavelet, and the scale vectors and the wavelet vectors were candidate for the feature spectra. Based on the testing results by Bayesian analysis, the 3rd scale vectors were the best feature segments at the division level and picked out as the fluorescence division feature spectra of those phytoplankton species, and the group of the 3rd scale vectors, the 2nd and 3rd wavelet vectors were the best feature segments at the genus level and chosen as the fluorescent genus feature spectra of those phytoplankton species. The reference spectra of those phytoplankton species at the division level and that at the genus level were obtained from these feature spectra by cluster analysis, respectively. The reference spectra base for 37 phytoplankton species was composed of 107 reference spectra at the division level and 155 ones at the genus level. Based on this reference spectra base, a fluorometric discriminating method for phytoplankton populations was established by multiple linear regression resolved by the nonnegative least squares. For 1 776 samples of single phytoplankton species, a correct discriminating rate of 97.0% at genus level and 98.1% at division level can be obtained; The correct discriminating rates are more than 92.7% at the genus level and more than 94.8% at the division level for 384 mixed samples from two phytoplankton species.

[Fluorescence characterization of dissolved organic matter in East China sea].

Sea water samples were collected in the East China Sea in March and April, 2005, and three-dimensional fluorescence of dissolved organic matter was measured by fluorescence excitation-emission matrix spectroscopy. The position, number and intensity of fluorescence peak in the spectra and the relations of the peaks were analyzed to determine the type, distribution and origin of the fluorescence dissolved organic matter. Seven types of fluorescence peaks were detected from the samples. There are protein-like fluorescence peaks B with Exmax/Emmax = 275/300 nm, D with Exmax/Emmax = 225/295-305 nm, T with Exmax/Emmax = 280/345 nm, and S with Exmax/Emmax = 225-240/320-350 nm, two humic-like peaks A with Exmax/Emmax = 250-255/410-455 nm and C 335-345/410-440 nm, and marine humic peak M with Exmax/Emmax = 305 nm/400-420 nm. Peaks B, S and A appeared in all surveyed area. Peaks T and D appeared in the north of the surveyed area. Peaks M and C only appeared in a few stations. In the surface layer, the source of the fluorescence dissolved organic matter might be the fresh water outflow of the Yangtze River, while the fluorescence dissolved organic matter in the middle layer had double sources from the Yangtze River and the phytoplankton. The good correlationships of different fluorescence peaks showed the same source or some relationship between the protein-like and the humic-like fluorescence dissolved organic matter.

Spatial distribution of dissolved Pb, Hg, Cd, Cu and As in the Bohai Sea.

Characteristics of the spatial distribution of selected dissolved heavy metals were analyzed during large scale surveys from August 12 to 25, 2003 in the Bohai Sea. Dissolved Pb was the only element with average concentrations higher than the grade-one sea water quality standard of China. The spatial distribution of dissolved Pb in surface water was similar to those of Cd, Cu and As, where the isopleths generally indicated decreasing values from the bays to the central areas. Only for Hg did the high concentrations not only appear in Liaodong Bay, Bohai Bay and Laizhou Bay, but also in the Central Area, viz. not only in inshore but also in offshore areas. Vertical distributions of dissolved Pb, Cd, Cu and As were largely uniform, while that of dissolved Hg increased with depth. We infer that the input of pollutants from land was the main influencing factor for the detected distribution patterns of dissolved heavy metals, followed by the dynamics of sea water, release from bottom sediments and biochemical processes. Comparing with historical data, average concentrations of dissolved heavy metals appear to decline in recent years.

[Study on the characters of phytoplankton chlorophyll fluorescence excitation spectra based on fourth-derivative].

Chlorophyll fluorescence excitation spectra of six phytoplankton species, belonging to Bacillariophyta and Dinophyta, were dealt by fourth-derivative analysis with the Matlab program. The results show that between 350 nm and 550 nm six fluorescence peaks were found in the fourth-derivative spectra, which are representatives of non-pigments, chlorophylls and carotenoides respectively. The method makes Bacillariophyta and Dinophyta more distinguishable when the fourth-derivative spectra are compared with the chlorophyll fluorescence excitation spectra. It can be used not only to discriminate the two groups of algaes, but also to reduce the effect of noise. The fluorescence peaks in the fourth-derivative spectra are proved to be stable.

[Research on characterization analysis of synchronous fluorescence spectra of living phytoplankton].

The synchronous fluorescence spectra of five phytoplankton species growing under three temperatures (25, 20 and 15 degrees C)and three illuminations (7000, 4100 and 1100 Lx)were measured and processed by multinomial smoothness and autoscaling to obtain the characteristic spectra. Principal component analysis was used to obtain standard spectra. The analysis shows that at different temperatures, the characteristic spectra of Skeletonema costatuma, Isochrysis galbana, and Platymonas helgolanidica show high similarities, while the spectra similarities of Alexandrium tamarense and Gymnodinium stein are not as good as the above three species. The standard spectrum of Skeletonema costatuma, which belongs to Bacillariophyta, is quite different from those of Alexandrium tamarense and Gymnodinium stein, which belong to Dinophyta.

[Synthesis and DNA binding spectroscopic studies of Cu(II)-HAsp-Im complexes].

Two novel complexes of [Cu(HAsp)ImH2O]SO4 x 4 H2O and [Cu(Asp)Im(OH)] x 4 H2O (HAsp = Aspartic acid molecule, Asp = Aspartic acid ion, Im = Imidazole) were synthesized and characterized by elemental analysis, IR spectroscopy and TG-DTA. The interactions of the complexes with sperm DNA were studied by electronic absorption and fluorescence spectra. Results showed that the reactions of the two complexes with DNA are obviously different: for [Cu(HAsp)ImH2O]SO4 x 4 H2O, it is intercalation companied by electrostatic effect, while [Cu(Asp)Im(OH)] x 4 H2O mainly cooperates with the nitrogen atom of the DNA base pair, which induces the breakage of DNA double helix. The reasons for these differences in their DNA binding modes were also discussed.

[Excitation-emission-matrix spectral property of dissolved organic matter in seawater of Jiaozhou Bay, China].

Excitation-emission matrix spectroscopy (EEMs) was applied to measure the fluorescence properties of dissolved organic matter (DOM) in seawater collected from Jiaozhou Bay in June, 2005. The study areas include central Bay area, receptor areas of Dagu River, Licun River and Haibo River. The aim was to investigate the influence of discharges from several typical rivers to the receiving seawater. Dagu River discharges mostly freshwater, while the other two rivers discharges include more wastewaters from factories and sewages treatments. The results indicate that there is a redshift of the position of humic-like fluorescence peaks due to the discharges from sewages and wastewaters from factories. The intensities of protein-like and humic-like peaks were the strongest in the samples from area near Haibo River and Licun River, while the weakest fluorescence intensities of both protein-like and humic-like were observed in the samples collected from central bay area. This suggests that river inputs are the mains sources of DOM in seawater of Jiaozhou Bay, while DOM produced by bioactivity in situ dominates those in central Bay area. The relationships of protein-like and humic-like fluorescence intensities vary depending on the water samples. The DOM in seawater of Jiaozhou Bay may be polluted by protein-like organic matter produced by human activity, as indicated by higher ratios of protein-like and humic-like fluorescence intensities. The results suggest the potential utility of EEMs technique for trace DOM and land-based pollution sources.

Synthesis, crystal structure and DNA binding studies of a binuclear copper(II) complex with phenanthroline.

A new binuclear copper(II) complex, [Cu2Phen2Cl4] (Phen=1,10-phenanthroline), has been synthesized and characterized. Single crystal X-ray diffraction results suggest that this complex structure belongs to monoclinic crystal system, Cc (no. 9) with the cell dimensions: a=9.849(2)A, b=17.833(4)A, c=13.374(3)A, beta=106.61(3) degrees , V=2251.0(8)A(3), Dc=1.8569 Mgm(-3), F(000)=1256.0, Z=4. One Cu(II) central atom situated in a distorted square planar geometry is four-coordinated. The other situated in a distorted square pyramidal geometry is five-coordinated. Only one bridging Cl atom exists in the complex. Spectroscopic studies, including electronic absorption and fluorescence spectra, conductivity measurements and parallel factor analysis (PARAFAC) of fluorescence excitation-emission three-way data array, were carried out on the DNA binding behavior of the complex. All the results suggested that the breakage of DNA secondary structure took place at low molar ratio of complex to DNA (0.3 at most) and intercalation into the base pair of DNA took place at high molar ratio. Additionally, the equilibrium concentration of EB-DNA and EB (EB: ethidium bromide) could be directly obtained by PARAFAC algorithm, proved to be a convincing method for studying the interaction of complexes with DNA.

Discrimination of phytoplankton classes using characteristic spectra of 3D fluorescence spectra.

The discrimination of phytoplankton classes using the characteristic fluorescence spectra extracted from three-dimensional fluorescence spectra was investigated. Single species cultures of 11 phytoplankton species, representing 5 major phytoplankton divisions, were used. The 3D fluorescence spectra of the cultures grown at different temperatures (20 and 15 degrees C) and illumination intensities (140, 80 and 30 microM m(-2) s(-1)) were measured and their feature extraction methods were explored. Ordering Rayleigh and Raman scattering data as zero, the obtained excitation-emission matrices were processed by both singular value decomposition (SVD) and trilinear decomposition methods. The resulting first principal component can be regarded as the characteristic spectrum of the original 3D fluorescence spectrum. The analysis shows that such characteristic spectra have a discriminatory capability. At different temperatures, the characteristic spectra of Isochrysis galbana, Platymonas helgolanidica and Skeletonema costatuma have high degrees of similarity to their own species samples, while the spectra similarities of Alexandrium tamarense, Prorocentrum dentatum, Pseudo-nitzschia pungens, Chaetoceros curvisetus, Ch. Debilis, Ch. Didymus and Synechococcus sp. are not as significant as the other three species. C. curvisetus, Ch. Debilis and Ch. Didymus, belonging to genus Chaetoceros, have identical spectra and cannot be discriminated at all. Regarding all six diatom species as one class, the average discriminant error rate is below 9%. It is worth mentioning that the diatom class can be distinguished from A. tamarense and P. dentatum, which belong to Dinophyta.

[Characteristics of absorption spectra of phytoplankton].

Nine typical phytoplankton species were chosen and cultivated under two temperatures (20 and 15 degrees C) and two illumi- nations (7000 and 1100 lux), and their absorption spectra at different growth period were measured. Firstly, singular value decomposition was used on the matrix, which is composed of the autoscaled spectra data. The S1/msigma(i=1)Si was used to compare the similarities of spectra. Twenty-five representative spectra were obtained for the nine species of phytoplankton. Among them, there are one spectrum for each of Isochrysis galbana and Chaetoceros Debilis, two for each of Platymonas helgolanidica and Chaetoceros curvisetus, three for Gymnodinium sp., and four for each of Alexandrium tamarense, Prorocentrum dentatum, Skeletonema costatuma and Synechococcus sp. Then, feature extraction was processed to obtain the characteristic spectra, including seven incontinuous wavelengths that have great ability to differentiate species. They are 340. 5-420. 5 nm, 423. 5-431 nm, 440.5-525.5 nm, 760.5, 763.5, 769.5 and 856.5 nm. Consequently, they form characteristic spectra. The discriminant result is 80%.

[Synthesis and DNA binding spectroscopy studies of Cu(II)-Thr-Phen].

A new complex [Cu (Thr)(Phen)H2O] SO4 . HO2 x CH3 OH (Thr = DL-Threonine, Phen = o-Phenanthroline), which has not been published, was synthesized and characterized by elemental analysis, IR spectroscopy, and TG-DTA. The interaction of the complex and sperm DNA was studied by electronic absorption and ethidium bromide (EB) fluorescence spectroscopy. The result indicates that the maximal absorption peaks of this complex are red-shifted and the intensity is weakened; At the same time, it can to some extent quench the emission intensity of EB-DNA system. Therefore, the authors come to a conclusion that the interaction of this complex and sperm DNA is intercalation.

[Research on discrimination of 3D fluorescence spectra of phytoplanktons].

Six phytoplankton species belonging to four divisions, which may cause red tide, were selected and cultivated under different temperature (20 degrees C and 15 degrees C) and illumination (7000, 4100 and 1100 Lux) in lab. 3D fluorescence spectra were measured in each growth period. Discrimination of these phytoplanktons' 3D fluorescence spectra was explored using discriminant analyses. The result showed that discriminant analyses based on the principal component analysis of spectra data was an efficient method. Isochrysis galbana, Platymonas helgolanidica and Skeletonema costatuma can be discriminated effectively. Skeletonema costatuma, which is an diatom, can be distinguished from Alexandrium tamarense and Prorocentrum micans which belong to Dinophyta.

[Fluorescence discrimination technique for phytoplankton based on the wavelet analysis].

Daubechies7 (db7) wavelet was selected to decompose the 3-D fluorescence spectra of 27 species of phytoplankton belonging to 22 generas of 6 divisions found in major lakes, then the scale vectors and time-series vectors were obtained as candidates for feature spectra. The third scale vector (Ca3) of db7 was chosen as feature spectra by Bayesian discriminant analysis, and the reference spectra were obtained via hierarchical cluster analysis to feature spectra. Based on the above data, a fluorescence discrimination technique was developed by multiple linear regression resolved by non-negative least squares. For single species algae cultures, the average correct discrimination ratio (CDR) was 98.6%, with the average relative content of 90.8% at division level. Furthermore, the noise immunity of reference spectra was tested by adding noise at different proportions. For the dominant division of laboratory mixed samples, the average CDR was 97.0%, with the average relative content of 67.7% at division level, and the average CDR of subdominant division was 90.7%, with the average relative content of 32.3%. The results showed that the technique is feasible to some extent.

[Estimation of the flux of inorganic nitrogen flowing into the East China Sea].

The flux of inorganic nitrogen flowing into the East China Sea was estimated based on the systematic analysis of all the pollution sources from 1980-2005. The result showed that the flux of inorganic nitrogen had been increasing from the early 1980s to the early 21st century. In detail, the flux was about 8.8 x 10(5) t x a(-1) in the early 1980s, and increased to about 2.6 x 10(6) t x a(-1) in the early of 21st century. The annual increasing rate was about 4.3%, and the mean flux was 1.8 x 10(6) t x a(-1). The flux of inorganic nitrogen of Yangtze River had also been increasing from early 1980s to the early 21st century. In detail, the flux was 4.0 x 10(5) t x a(-1) in the early 1980s, and increased to about 6.2 x 10(5) t x a(-1) in the middle 1980s, and was then kept at this value to the end of 1980s. After that, the flux value increased quickly from the early 1990s to 1.8 x 10(6) t x a(-1) in the early 21st century. Of all the sources, the proportion of land-source inorganic nitrogen was the largest, which was about 79%, among which, the river-source, the sewage-source and the non-point source accounted for 73%, 4% and 2%, respectively. Besides the land-source, the air-source and the mariculture-source accounted for 18% and 3%. The proportion of flux of Yangtze River in the river source was 76.5%.

[Toxic effects of chloride tributyltin on the predominant phytoplankton species of China coastal sea].

Toxic effects of tributyltin (TBT) on the growth, peak diameter and photosynthetic activity (F(v)/F(m)) of fifteen predominant phytoplankton species in China coastal sea of Leptocylindru danicus, Skeletonema marinoi, Asterionella japonica, Bacilaria paxillifera, Chaetoceros debilis, Chaetoceros socialis, Thalassiosira, Amphidinium carterae, Karenia mikimotoi, Prorocentrum minimum, Gymnodinium sp., Scrippsiella trochoidea, Gymnodinium simplex, Prorocentrum triestinum and Heterosigma akashiwo were systematically studied. 96 h-EC50 of TBT were 136.42, 3.55, 3.15, 2.95, 1.90, 1.08, 0.70, 21.60, 7.71, 4.77, 3.81, 2.04, 0.53, 0.51, 1.76 microg/L, respectively. The no detectation effect concentration were 112.62, 1.19, 1.17, 3.70, 0.95, 1.07, 0.80, 6.28, 1.84, 0.99, 3.73, 1.63, 0.23, 0.16, 1.76 microg/L, respectively. The results indicated that the toxic effects of TBT were very different among different phytoplankton species and the resistance of Leptocylindru danicus was stronger than those of other microalgae. The TBT not only inhibited the growth of phytoplankton, but also changed the peak diameter and decreased the photosynthetic activity (F(v)/F(m)). Besides that, we infer that there may have a relationship between the toxicity of TBT and the composition of predominant phytoplankton population in harbour.

Significant fluorescence enhancement by supramolecular complex formation between berberine chloride and cucurbit(n=7)uril and its analytical application.

The supramolecular interaction of cucurbit(n=7)uril (Q[7]) with berberine chloride (BER) has been studied in aqueous solution at pH 2.0 and room temperature by spectro-fluorimetry. The association constant of the complex was 2.07 × 10(6) L mol(-1) calculated by using a nonlinear least squares method. (1)H NMR spectra confirmed that a 1:1 stable complex is formed between Q[7] and BER. This work proposes a possible interaction mode, in which the guest BER is incorporated inside the hydrophobic cavity of the host Q[7] via the isoquinoline ring part of the guest molecule. Based on a significant enhancement of the fluorescence intensity of this supramolecular complex, a spectrofluorimetric method with high sensitivity and selectivity has been developed for the determination of BER in aqueous solution in the presence of Q[7]. The linear range of the method was from 7.43 to 11.2 × 10(3) ng mL(-1)with the detection limit 4.2 ng mL(-1). There was no interference from the compounds normally used in tablets, serum or urine constituents. The proposed method was applied to the determination of BER in tablets, serum and urine samples with satisfactory results and good consistency with those obtained by the pharmacopoeia method. This shows that it has promising potential for therapeutic drug monitoring and pharmacokinetics and for clinical application.

[Role of irradiance on the seasonality of Skeletonema costatum Cleve blooms in the coastal area in East China Sea].

With field culture experiments and model calculations, the role of light on why in both spring and summer Skeletonema costatum Cleve blooms can occur in the coastal area in East China Sea were studied. The results show that the growth optimal light intensity (I(opt)) of S. costatum increases gradually to a maximum of 121.6 W x m(-2) with temperature (t) up to 25 degrees C, and a rapid decline in I(opt) accompanies further increases in t beyond 25 degrees C. Such an asymmetric inverse V-shape I(opt)-t curve can be well described by Blanchard's equation. By this equation, I(opt) of each month was calculated based on monthly sea surface temperature, and though changes about 2 months later than light intensity above sea surface (I(0)), I(opt) is closely correlated with seasonal I(0) and transparency of sea water (R2 = 0.907 +/- 0.115, p < 0.001), which indicates that S. costatum adapts to the seasonality of light in sea water in the coastal area by varying I(opt) seasonally. Such an adaptive strategy leads to thick (about 6 m) light-optimal water layers for growth from early spring to late summer. The high adaptability to light and light optimum characteristics in sea water is one of the important reasons for S. costatum blooms in the both seasons in the coastal area in ECS.

[Effects of irradiance on blooms of the dinoflagellate Prorocentrum donghaiense Lu in the coastal area in East China Sea].

With field culture experiments and model calculations, the natural-light-dependent growth and the optimal light layers in sea water for growth of red tide dinoflagellate Prorocentrum donghaiense Lu were studied in order to analyze the role of light on algal blooms in the coastal area in East China Sea in spring. The results show that the relationship of growth and light can be well described by Steele's equation, and the optimal light intensity (Iopt) of P. donghaiense is (38.2 +/- 3.8) W x m(-2), which is lower than Iopt for several other red tide algae (40-133 W x m(-2)), meaning that P. donghaiense may have an advantage when developing blooms in turbid environments where solar irradiance is easily attenuated. The optimal light layers for P. donghaiense growth are thicker offshore than inshore, and the thickness of optimal light layers in the subsurface water usually in 3-15 m in depth is about 5-10 m in the red tide area. The trade-off of light and nutrient fitness results in blooms in the so-called red tide area, and the light-optimum characteristic of the subsurface water is an important factor for the subsurface bloom development in spring.