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Ten compounds (1~10) were successfully isolated from green algae Ulva prolifera through the combination of silica gel column chromatography, Sephadex LH-20 column chromatography and repeated preparative thin-layer chromatography. These ten compounds showed antialgal activity against red tide microalgae. Among them, compounds 3, 6, and 7 showed stronger antialgal activity against red tide microalgae. Furthermore, their structure was identified on the basis of spectroscopic data. There are three glycoglycerolipids: 1-O-octadecanoic acid-3-O-β-D-galactopyranosyl glycerol (2), 1-O-palmitoyl-3-O-β-D-galactopyranosyl glycerol (4), and 1-O-palmitoyl-2-O-oleoyl-3-O-β-D-galactopyranosyl glycerol (5); two monoglycerides: glycerol monopalmitate (1), 9-hexadecenoic acid, 2,3-dihydroxypropyl ester (3); two terpenoids: loliolide (6) and lsololiolide (7); one lipid-soluble pigments: zeaxanthin (8); one sterol: cholest-5-en-3-ol (9); and one alkaloid: pyrrolopiperazine-2,5-dione (10). These compounds were isolated from U. prolifera for the first time, and compounds 2, 3, 5, and 8 were isolated from marine macroalgae for the first time.

Seven antialgal compounds ( 1 – 7 ) were successfully isolated from the red alga Gracilaria lemaneiformis through a combination of silica gel column chromatography and repeated preparative thin-layer chromatography. On the basis of the spectral data, the compounds were identified as gossonorol ( 1 ), 7,10-epoxy-ar-bisabol-11-ol ( 2 ), glycerol monopalmitate ( 3 ), stigmasterol ( 4 ), 15-hydroxymethyl-2, 6, 10, 18, 22, 26, 30-heptamethyl-14-methylene-17-hentriacontene ( 5 ), 4-hydroxyphenethyl alcohol ( 6 ), and margaric acid ( 7 ). These seven compounds were isolated from G. lemaneiformis for the first time, while the compounds 4 , 6 , and 7 were isolated from marine macroalgae for the first time. Furthermore, a quantitative relationship between the inhibition of algal growth and the concentration of each antialgal compound was determined and important parameters for future practical HAB control, e.g., EC 50-96h , were also obtained. The results indicated that isolated compounds 1–7 possess selective antialgal activity against the growth of several red tide microalgae (including Amphidinium carterae , Heterosigma akashiwo , Karenia mikimitoi , Phaeocystis globsa , Prorocentrum donghaiense , and Skeletonema costatum ). Their antialgal activity against test red tide microalgae has not been previously reported. Furthermore, the EC 50-96h of one or more of the compounds towards the tested red microalgae was not only significantly less than 10 μg/mL but also was smaller than that of the characteristic antialgal agent potassium dichromate. The study demonstrates that compounds 1–7 possess significant application potential as antialgal agents against several harmful red tide microalgae.

Sun, Y.; Dong, S.; Zhou, W.; Guo, L.; Guo, G., and Zhang, X., 2019. A comprehensive review of secondary metabolites with antialgal activity from marine macroalgae against red tide microalgae. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 475–488. Coconut Creek (Florida), ISSN 0749-0208. Red tide, mainly caused by the large-scale reproduction of microscopic algae, has virtually affected every coastal country or region in the whole world over the last several decades. In order to control and mitigate the proliferation and diffusion of red tide microalgae, there are many methods or strategies for fighting or inhibiting red tide microalgae species, these methods or strategies included mechanical, chemical, biological, genetic methods and others. Unfortunately, the use of these methods or strategies is usually ineffective. There are some evidences that the inhibition effect of marine macroalgae on the growth of red tide microalgae is mainly due to the release of bioactive molecules, which are mainly secondary metabolites. Thus, antialgal secondary metabolites, isolated marine macroalgae, have become an environmentally friendly alternative approach. And relevant researches of antialgal secondary metabolites in marine macroalgae, such as screen, isolation, identification and other research etc., have also become very important subjects to biological control of red tide microalgae. The inhibition effects of marine macroalgae on red tide microalgae are here reviewed, focusing on antialgal secondary metabolites, isolated from marine macroalgae, against red tide microalgae growth. Further, this paper describes isolation and EC50-96 h (half maximal effective concentration) or IC50-96 h (half maximal inhibitory concentration) for red tide microalgae of some antialgal secondary metabolites, including the recently discovered compounds. Finally, this review is the first to demonstrate that development relationships between macroalgae and red tide using CiteSpace, and cluster view of macroalgae and red tide is given for the first time. This work provides scientists in the field with the necessary information and the urgent need to isolate and identify screening antialgal secondary metabolites in different marine macroalgae. Also, analysis result, which obtained through CiteSpace, has pointed out that allelopathic interaction between marine macroalgae and red tide microalgae has been developed into a study area during the last twenty years.

We tested the effects of solvent fractions (F A , F B , F C , and F D ), which partitioned by liquid-liquid extraction from the methanol extract of Ulva pertusa , on the growth of red tide microalgae ( Karenia mikimitoi , Skeletonema costatum , Alexandrium tamarense, Heterosigma akashiwo , Prorocentrum donghaiense ), and F A , F B , and F C exhibited significantly antialgal activity. The chemical constituent analysis showed the existence of bioactive compounds such as phenols and alkaloids. Further, four solvent fractions were applied to silica gel column and repeated preparative TLC to produce 13 samples and their purity qualified as thin-layer chromatographic grade. Among these purified samples, F A111 , F B411, F C411 , F D111 , and F D211 exhibited stronger antialgal activity. Furthermore, their functional groups were analyzed by colorimetric methods and UV spectra data. F D111 and F D211 were temptatively identified as alkaloids; the others were initially identified as phenolic acids. This is a preliminary study and the structure identification of these purified samples requires further investigation. While concentration of these purified samples in this algae was very small, they showed excellent effects against red tide microalgae.

Laboratory studies were undertaken to determine the growth and chemical constituents of Ulva pertusa at fluctuating light density treatments. Results showed that the specific growth rates (SGR) of Ulva pertusa significantly increased at the fluctuating light density treatments than the constant light density. The ratios of Chl a / Chl b varied with the fluctuating light density. The protein contents of Ulva pertusa increased at fluctuating light density. In contrast, the soluble sugars contents of U. pertusa decreased at fluctuating light density.

The objectives of this study were to investigate the effect of fermentation medium on the DPPH radical scavenging activity of exopolysaccharides from marine Penicillium chrysogenum HGQ6 by response surface methodology (RSM). A two-level fractional factorial design was used to evaluate the effect of different components of the medium. Maltose, FeSO4, and K2HPO4 were important factors significantly affecting DPPH radical scavenging activity. These selected variables were subsequently optimized using a Box-Behnken design, and response surface analysis. The optimal medium compositions were (% w/v): maltose 2.71, FeSO4 0.0016, K2HPO4 0.1, and KNO3 1.0. Under these optimal conditions, the DPPH radical scavenging rate achieved 34.0%, which agreed with the predicted values.

In May and July 2001, the biological and ecological features of 22 salt lakes in northern Tibet , China, were investigated.Their salinity ranged from 1 to 390 g l^sup -1^. One hundred and thirty two samples were collected. Ninty five taxa of phytoplankton and 42 taxa of zooplankton were recorded. The dominant cation was sodium, with magnesium generally sub-dominant; CO^sub 3^^sup 2-^ was the dominant anion in low salinity, chloride was the dominant anion with increasing salinity. Major species were Gloeothece linearis, Oscillatoria tenuis, Chroococcus minutus (blue-green algae); Navicula spp, Cymbella pusilla, Diatoma elongatum(diatoms); Dunaliella salina, Chlorella vulgarisand Ulothrix tenerrima (green algae). Major zooplankton included: Vorticella campanula, Epistylis daphniae (Protista); Keratella quadrata, Brachionus plicatilis (Rotifera); Artemiaspp. (Anostraca); Daphniopsis tibetana (Cladocera); Cletocamptus dertersiand Cyclops vicinus (Copepoda). Ten species were recorded in hypersaline waters; apart from those metioned above, they included CyclidiumsppLitonotus fasciola, Euplotes terricola, Strombilidium viride, Brachionus variabilis, Colurella adriatica, Keratella cochlearis, Colurella adriatica, and Cyclops sp. Seven taxa of benthic macroinvertebrates are recorded, represented by Cyprissp. (Ostracoda), Gammarus sp. (Amphipoda), Radixsp. and Hippeutis sp. (Mollusca); chiroonomids Tendipus group salinarius (Diptera), Nematoda, Trochophora and Ephrdra sp. At present, there are fishes only in Bangong Co., and no fishes recorded in other salt lakes. The total number of plankton species has a significantly negative correlation with the salinity, and decreased with increasing altitude, but not significant.[PUBLICATION ABSTRACT]

Jinping Underground laboratory for Nuclear Astrophysics（JUNA） will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of（25）Mg（p,γ）（26）Al,（19）F（p,α）（16）O,（13）C（α,n）（16）O and （12）C（α,γ）（16）O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.

Experimental data of β--decay half-lives of nuclei with atomic number between 20 and 190 are investigated. A systematic formula has been proposed to calculateβ--decay half-lives of neutron-rich nuclei, with a particular consideration on shell and pair effects, the decay energy Q as well as the nucleon numbers （Z, N）. Although the formula has relatively few parameters, it reproduces the experimentalβ--decay half-lives of neutron-rich nuclei very well. The predicted half-lives for the r-process relevant nuclei obtained with the current formula serve as reliable input in the r-process model calculations.