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1.
Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and identified. The bacteria fermentation broth could exert inhibitory effects on the growth of Skeletonema costatum and barnacle larvae. A procedure was employed to extract and identify the antifouling compounds. Firstly, a toxicity test was conducted by graduated pH and liquid-liquid extraction to determine the optimal extraction conditions. The best extraction conditions were found to be pH 2 and 100% petroleum ether. The EC50 value of the crude extract of K. sedentarius against the test microalgae was 236.7 ± 14.08 μg mL-1, and that of B. cereus was 290.6 ± 27.11 μg mL-1. Secondly, HLB SPE columns were used to purify the two crude extracts. After purification, the antifouling activities of the two extracts significantly increased: the EC50 of the K. sedentarius extract against the test microalgae was 86.4 ± 3.71 μg mL-1, and that of B. cereus was 92.6 ± 1.47 μg mL-1. These results suggest that the metabolites produced by the two bacterial strains are with high antifouling activities and they should be fatty acid compounds. Lastly, GC-MS was used for the structural elucidation of the compounds. The results show that the antifouling compounds produced by the two bacterial strains are myristic, palmitic and octadecanoic acids. 相似文献
2.
Yu Yuan Wang Le Fu Xiaoting Wang Lei Fu Xiaodan Yang Min Han Zhenlian Mou Haijin Jeon You-Jin 《中国海洋湖沼学报》2019,37(3):836-847
Polypehnol is an important, potentially bioactive component of Sargassum muticum. In this study, ultrasonic assisted extraction of polyphenol-rich substances was performed using a 38% ethanol solution at a solid:liquid ratio of 1:30 at 68℃ for 32 min, determined by single-factor and response surface methodology(RSM) optimization. The content of polyphenol was 5.66 mg/g in the crude extract. Further extraction showed that the polyphenol mainly distributed in ethyl acetate(SKEE) and water phases(SKEW).The anti-oxidation test by electron spin resonance(ESR) spectrum showed that the SKEE had the strongest scavenging activity on DPPH(1,1-diphenyl-2-picrylhydrazyl) and alkyl radicals. SKEE was shown noncytotoxic but could inhibit the generation of cellular ROS, showing protective effects in H_2O_2 and AAPHinduced Vero cells and UV-B irradiated HaCaT cells. SKEE also significantly inhibited the release of NO of LPS-induced RAW 264.7 cells. Therefore, the polyphenol-rich extracts in ethanol and ethyl acetate showed excellent anti-oxidant and anti-inflammatory activities, which is beneficial to the development of high-value bio-substances. 相似文献
3.
In recent years, red tides occurred frequently in coastal areas worldwide. Various methods based on the use of clay, copper sulfate, and bacteria have been successful in controlling red tides to some extent. As a new defensive agent, marine microorganisms are important sources of compounds with potent inhibitory bioactivities against red-tide microalgae, such as Gymnodinium sp. （Pyrrophyta）. In this study, we isolated a marine bacterium, HSB07, from seawater collected from Hongsha Bay, Sanya, South China Sea. Based on its 16S rRNA gene sequence and biochemical characteristics, the isolated strain HSB07 was identified as a member of the genus Halomonas. A crude ethyl acetate extract of strain HSB07 showed moderate inhibition activity against Gymnodinium sp. in a bioactive prescreening experiment. The extract was further separated into fractions A, B, and C by silica gel column chromatography. Fractions B and C showed strong inhibition activities against Gymnodinium. This is the first report of inhibitory activity of secondary metabolites of a Halomonas bacterium against a red-tide-causing microalga. 相似文献
4.
We conducted a phenological evaluation of Sargassum thunbergii, a common algal species, along the coast of Lidao Bay, Rongcheng, China. The local S. thunbergii population entered a maturation period from early June to mid-August, when seawater temperature was 14.4 to 25.1°C. Our results suggest an increase in temperature and day length during this period initiated thalli maturation. Inhabitants of the low tidal zone had higher thalli length and biomass compared with those from the mid-and high tidal zones. We observed a switch in the length frequency distribution and contribution of length classes to biomass between the small (<20 cm) and long (20–79.9 cm) length classes at the time of thallus maturity. This suggests there is a trade-offbetween sexual reproduction and vegetative regeneration. 相似文献
5.
The polar and nonpolar extracts of Colpomenia sinuosa, Padina pavonia, Cystoseira barbata and Sargassum vulgare collected during spring, summer and autumn were evaluated for their antifungal activities. The phytochemicals of unexplored seaweeds were analyzed by gas chromatography and mass spectrometric (GC/MS). The algal extracts were tested for their antifungal activities against Aspergillus niger, A. flavus, Penicillium parasiticus, Candida utilis and Fusarium solani. Phytochemicals were extracted from the four seaweeds with various solvents including methanol, ethanol, acetone, chloroform and dimethyl ether. Among the various extracts, methanolic extract showed the highest inhibition activity on all fungal species. Seasonal variation in antifungal activity was studied, while methanol extracts showed the best antifungal activity in spring. Cystoseira barbata was the most effective seaweed, having antifungal activity throughout the whole year. The UV-Vis phytochemical procedure and GC-MS analysis of the methanol extracts from tested species indicated the existence of different constituents. In conclusions, the compounds with antifungal activity were identified as indoles, terpenes, acetogenins, phenols, and volatile halogenated hydrocarbons. 相似文献
6.
The present study was conducted to determine the change of digestive physiology in sea cucumber Apostichopus japonicus(Selenka) induced by corn kernels meal and soybean meal in diets. Four experimental diets were tested, in which Sargassum thunbergii was proportionally replaced by the mixture of corn kernels meal and soybean meal. The growth performance, body composition and intestinal digestive enzyme activities in A. japonicus fed these 4 diets were examined. Results showed that the sea cucumber exhibited the maximum growth rate when 20% of S. thunbergii in the diet was replaced by corn kernels meal and soybean meal, while 40% of S. thunbergii in the diet can be replaced by the mixture of corn kernels meal and soybean meal without adversely affecting growth performance of A. japonicus. The activities of intestinal trypsin and amylase in A. japonicus can be significantly altered by corn kernels meal and soybean meal in diets. Trypsin activity in the intestine of A. japonicus significantly increased in the treatment groups compared to the control, suggesting that the supplement of corn kernels meal and soybean meal in the diets might increase the intestinal trypsin activity of A. japonicus. However, amylase activity in the intestine of A. japonicus remarkably decreased with the increasing replacement level of S. thunbergii by the mixture of corn kernels meal and soybean meal, suggesting that supplement of corn kernels meal and soybean meal in the diets might decrease the intestinal amylase activity of A. japonicus. 相似文献
7.
采用直接甲酯化、乙醚抽提、正己烷提取等3种方法对微拟球藻进行前处理,用索氏法提取油脂,经气相色谱分析,对比前处理方法对微拟球藻油脂提取率及脂肪酸组分的影响。结果表明:乙醚提取藻粉油脂的提取率(微藻的油脂质量分数)为12.70%,正己烷提取藻粉油脂的提取率为11.00%,乙醚提取油脂的提取率大于正己烷的提取率;直接甲酯化后测得微拟球藻脂肪酸中多不饱和脂肪酸(Polyunsaturated Fatty Acids,PUFAs)质量分数为20.04%,多不饱和脂肪酸中二十碳五烯酸(Eicosapentaenoic Acid,EPA)含量最丰富,占总脂肪酸13.0%;经过乙醚和正己烷提取后的油脂,脂肪酸组成更加简单,PUFAs含量明显增加,乙醚提取油脂EPA含量是直接甲脂化法的2.3倍,正己烷提取所得油脂EPA含量是直接甲脂化法的2.08倍。 相似文献
8.
PHYSIOLOGICAL INHIBITORY EFFECT OF OCS IN ARACHIDONIC ACID-RICH PARIETOCHLORIS INCISA （TREBOUXIOPHYCEAE, CHLOROPHYTA） 总被引：2，自引：0，他引：2
Parietochloris incisa is an arachidonic acid-rich snow green alga. The main physiological profiles, such as ash free dry weight (AFDW), chlorophyll, carotenoid, protein and total fatty acids (TFA), in this alga exposed to old culture supernatant (OCS) at the decline phase or its crude ethyl acetate extracts (CEAE) were investigated by using tubular photobioreactors of different diameters. Results showed that both OCS and CEAE had strong inhibitory effect on the above physiological parameters. The longer the culture was exposed to OCS and the more CEAE were added into the algal culture, the more the above physiological properties were inhibited. Arachidonic acid (AA), the dominant component of fatty acids in this alga, was also seriously inhibited with respect to total TFA, AFDW of cell mass, or culture volume, due to a prebable reduction of enzymes activities catalyzing chain elongation from C18:1ω9 to AA. These results incontestably evidenced that some CEAE dissolving substances existing in OCS, like auto-inhibitors, inhibited P. incisa growth through feedback. Hence, any efficient removal of auto-inhibitors from algal culture to decrease their bioactivity could be good for maximal production of desired products like AA. 相似文献
9.
The purpose of this study was to investigate the antibacterial activity of extracts from Zostera marina against the pathogens of Apostichopus japonicus skin ulceration disease. When 95% ethanol (v/v) solvent was used to extract Zostera marina at 50°C, aqueous extract (ZA) showed obvious bacteriostatic effects on the tested bacterial strains (inhibition halo diameters
between 8.23 mm and 13.62 mm), whereas the ethyl acetate extract (ZE) was almost inactive. The minimal inhibitory concentration
(MIC) of ZA against four pathogens were homogeneous at 12.8 g L−1. ZA components were analyzed by thin layer chromatography (TLC) assay and six fractions were obtained. In another study,
the six fractions showed inhibitory effects against the tested bacteria while their functions seemed to counteract the ZA
activity. 相似文献
10.
Ten actinomycete strains isolated from the Yellow Sea off China's coasts were identified as belonging to two genera by 16 S r DNA phylogenetic analysis: Streptomyces and Nocardiopsis. Six Streptomyces strains(MA10, 2SHXF01-3, MA35, MA05-2, MA05-2-1 and MA08-1) and one Nocardiopsis strain(MA03) were predicted to have the potential to produce aromatic polyketides based on the analysis of the KSα(ketoacyl-synthase) gene in the type II PKS(polyketides synthase) gene cluster. Four strains(MA03, MA01, MA10 and MA05-2) exhibited significant inhibitory effects on mycelia growth(inhibition rate 50%) and subsequent aflatoxin production(inhibition rate 75%) of the mutant aflatoxigenic Aspergillus parasiticus NFRI-95. The ethyl acetate extracts of the broth of these four strains displayed significant inhibitory effects on mycelia growth, and the IC50 values were calculated(MA03: 0.275 mg m L-1, MA01: 0.106 mg m L-1, MA10: 1.345 mg m L-1 and MA05-2: 1.362 mg m L-1). Five strains(2SHXF01-3, MA03, MA05-2, MA01 and MA08-1) were selected based on their high cytotoxic activities. The ethyl acetate extract of the Nocardiopsis strain MA03 was particularly noted for its high antitumor activity against human carcinomas of the cervix(He La), lung(A549), kidney(Caki-1) and liver(Hep G2)(IC50: 2.890, 1.981, 3.032 and 2.603 μg m L-1, respectively). The extract also remarkably inhibited colony formation of He La cells at an extremely low concentration(0.5 μg m L-1). This study highlights that marine-derived actinomycetes are a huge resource of compounds for the biological control of aflatoxin contamination and the development of novel drugs for human carcinomas. 相似文献
11.
1 INTRODUCTION In recent decades, red tides that induced by in- creasing eutrophication occur frequently in coastal areas worldwide. This has caused serious problems in marine environment, aquaculture industries and human health (Qi et al., 1993; Horner e… 相似文献
12.
Results of neutron activation analysis (NAA) ofSargassum thumbergii samples collected from the Qingdao Taipingjiao coast on March 20, 1996 showed that (1)Sargassum thunbergii can to some extent accumulate potassium and calcium (the accumulation coefficient was 10); (2) it can accumulate almost all
trace elements, especially iron, managanese and zinc; (3) it can accumulate strontium, aluminium thorium, and rare earth elements.
Contribution No.3308 from the Institute of Oceanology, Chinese Academy of Sciences.
The study supported by the National Ninth-Five-Year Key Project “96-916-04-01”. 相似文献
13.
Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae. Close relationships exist among lipid production, microalgal species, and nitrogen sources. We report growth, lipid accumulation, and fatty acid composition in four microalgae （Chloroeoccum ellipsoideum UTEX972, Chlorococcum nivale LB2225, Chlorococcum tatrense UTEX2227, and Scenedesmus deserticola JNU19） under nitrate- and urea-nitrogen deficiencies. We found three patterns of response to nitrogen deficiency： Type-A （decrease in biomass and increase in lipid content）, Type-B （reduction in both biomass and lipid content）, and Type-C （enhancement of both biomass and lipid content）. Type-C microalgae are potential candidates for large-scale oil production. Chlorococcum ellipsoideum, for example, exhibited a neutral lipid production of up to 239.6 mg/（L＇d） under urea-nitrogen deficiency. In addition, nitrogen deficiency showed only a slight influence on lipid fractions and fatty acid composition. Our study provides useful information for further screening hyper-lipid microalgal strains for biofuel production. 相似文献
14.
新鲜鱼油中添加05、0、2505、00 mg/kg 4种不同浓度的维生素E醋酸酯,在实验的第6、14、28、36和68天测定鱼油中的脂肪酸含量。结果表明:在500 mg/kg添加量内,维生素E醋酸酯对鱼油中脂肪酸含量没有显著性影响(P>0.05)。在实验期间,EPA(C20:5)、DHA(C22:6)、亚油酸(C18:2)含量明显下降,ARA(C20:4)、亚麻酸(C18:3)先升后降,棕榈酸(C16:1)逐步上升;C14含量逐渐增加,C17则先降后升,C16和C18在实验后期有较大提高。维生素E醋酸酯对鱼油中不饱和脂肪酸效用系数大小依次为:ARA>EPA>DHA>C18:3>0>C16:1>C18:2>C18:1,对ARA抗氧化效用最大,效用系数达到10.193%,C20:5为0.490%,C22:6为0.364%;维生素E醋酸酯对饱和脂肪酸效用系数大小依次为:C14>C17>0>C18>C16。 相似文献
15.
Twenty species of seaweed were collected from the coast of Zhejiang, China, extracted with ethanol, and screened for algicidal activity against red tide microalgae Heterosigma akashiwo and Prorocentrum micans. Inhibitory effects of fresh and dried tißsues of green alga Ulva intestinalis were assessed and the main algicidal compounds were isolated, purified, and identified. Five seaweed species, U. intestinalis, U. fasciata, Grateloupia romosissima, Chondria crassicaulis, and Gracilariopsis lemaneiformis, were investigated for their algicidal activities. Fresh tissues of 8.0 and 16.0 mg/mL of U. intestinalis dissolved in media significantly inhibited growth of H. akashiwo and P. micans, respectively. Dried tissue and ethyl acetate (EtOAc) extracts of U. intestinalis at greater than 1.2 and 0.04 mg/mL, respectively, were fatal to H. akashiwo, while its water and EtOAc extracts in excess of 0.96 and 0.32 mg/mL, respectively, were lethal to P. micans. Three algicidal compounds in the EtOAc extracts were identified as 15-ethoxy-(6z,9z,12z)-hexadecatrienoic acid (I), (6E,9E,12E)-(2-acetoxy-β-D-glucose)-octadecatrienoic acid ester (II) and hexadecanoic acid (III). Of these, compound II displayed the most potent algicidal activity with IC50 values of 4.9 and 14.1 µg/mL for H. akashiwo and P. micans, respectively. Compound I showed moderate algicidal activity with IC50 values of 13.4 and 24.7 µg/mL for H. akashiwo and P. micans, respectively. These findings suggested that certain macroalgae or products therefrom could be used as effective biological control agents against red tide algae. 相似文献
16.
We evaluated the effects of high molecular-weight phlorotannins from Sargassum thunbergii(STP) on ADP-induced platelet aggregation and arachidonic acid(AA) metabolism in New Zealand white rabbits and Wistar rats.The inhibition of STP on platelet aggregation was investigated using a turbidimetric method,and the levels of the terminal products of AA metabolism were measured using the corresponding kits for maleic dialdehyde(MDA),thromboxane B2(TXB2) and 6-keto-prostaglandin F1α(6-keto-PGF1α) by colorimetry an... 相似文献
17.
Genetic modification is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. Synechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid (GLA) and stearidonic acid (SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6D, Syd15D and Syd6Dd15D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in Synechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content. 相似文献
18.
Xianyu Kong Xiurong Han Min Gao Rongguo Su Ke Wang Xuzhao Li Wei Lu 《中国海洋大学学报(英文版)》2016,15(6):1014-1020
With the global ban on the application of organotin-based marine coatings by the International Maritime Organization, the development of environmentally friendly, low-toxic and nontoxic antifouling compounds for marine industries has become an urgent need. Marine microorganisms have been considered as a potential source of natural antifoulants. In this study, the antifouling potential of marine dinoflagellate Amphidinium carterae, the toxic and red-tide microalgae, was investigated. We performed a series of operations to extract the bioactive substances from Amphidinium carterae and tested their antialgal and antilarval activities. The crude extract of Amphidinium carterae showed significant antialgal activity and the EC50 value against Skeletonema costatum was 55.4 μg mL?1. After purification, the isolated bioactive substances (the organic extract C) exhibited much higher antialgal and antilarval activities with EC50 of 12.9 μg mL?1 against Skeletonema costatum and LC50 of 15.1 μg mL?1 against Amphibalanus amphitrite larvae. Subsequently, IR, Q-TOFMS, and GC-MS were utilized for the structural elucidation of the bioactive compounds, and a series of unsaturated and saturated 16- to 22-carbon fatty acids were detected. The data suggested the bioactive compounds isolated from Amphidinium carterae exhibited a significant inhibiting effect against the diatom Skeletonema costatum and Amphibalanus amphitrite larvae, and could be substitutes for persistent, toxic antifouling compounds. 相似文献
19.
Artificial seedling production of Sargassum thunbergii is an effective way to relieve pressure on natural resources. In order to improve the utilization of zygotes and reduce the loss of seedlings, studies on the characteristic of the zygotes release, the development of rhizoids, the attachment of germlings, and the influence of jet washing were conducted. Results show that the percent of zygotes released was increased with time in the first 60 h. The capacity of germlings attached to the substratum was significantly increased, especially coincident with the time of the new rhizoids emerged and elongated. The detachment rate of germlings significantly decreased with the delay of starting time of jet washing or the reduction of jet washing velocity. However, the jet washing at any level applied in the experiment could cause considerable loss of germlings within the 20 days after the attachment. Our study provided some parameters to optimize the operation in the early stage of seedling production. 相似文献
20.
Nannochloropsis oculata CS179, a unicellular marine microalga, is rich in long-chain polyunsaturated fatty acids (LCPUFAs). Elongase and desaturase
play a key role in the biosynthesis of PUFAs. A new elongase gene, which encodes 322 amino acids, was identified via RT-PCR and 5′ and 3′ RACE. The sequence of the elongase gene was blast-searched in the NCBI GenBank and showed a similarity
to those of the cryptosporidium. But the NJ-tree revealed that the N. oculata CS179 elongase clustered with those of the microalgae Phaeodactylum tricornutum, Ostreococcus tauri and Thalassiosira pseudonana. 相似文献