Antitumor and Antimicrobial Potential of Bromoditerpenes Isolated from the Red Alga,Sphaerococcus coronopifolius

Cancer and infectious diseases continue to be a major public health problem, and new drugs are necessary. As marine organisms are well known to provide a wide range of original compounds, the aim of this study was to investigate the bioactivity of the main constituents of the cosmopolitan red alga, Sphaerococcus coronopifolius. The structure of several bromoditerpenes was determined by extensive spectroscopic analysis and comparison with literature data. Five molecules were isolated and characterized which include a new brominated diterpene belonging to the rare dactylomelane family and named sphaerodactylomelol (1), along with four already known sphaerane bromoditerpenes (2–5). Antitumor activity was assessed by cytotoxicity and anti-proliferative assays on an in vitro model of human hepatocellular carcinoma (HepG-2 cells). Antimicrobial activity was evaluated against four pathogenic microorganisms: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. Compound 4 exhibited the highest antimicrobial activity against S. aureus (IC₅₀ 6.35 µM) and compound 5 the highest anti-proliferative activity on HepG-2 cells (IC₅₀ 42.9 µM). The new diterpene, sphaerodactylomelol (1), induced inhibition of cell proliferation (IC₅₀ 280 µM) and cytotoxicity (IC₅₀ 720 µM) on HepG-2 cells and showed antimicrobial activity against S. aureus (IC₅₀ 96.3 µM).     

Assessment of the Antimicrobial Activity of Algae Extracts on Bacteria Responsible of External Otitis

External otitis is a diffuse inflammation around the external auditory canal and auricle, which is often occurred by microbial infection. This disease is generally treated using antibiotics, but the frequent occurrence of antibiotic resistance requires the development of new antibiotic agents. In this context, unexplored bioactive natural candidates could be a chance for the production of targeted drugs provided with antimicrobial activity. In this paper, microbial pathogens were isolated from patients with external otitis using ear swabs for over one year, and the antimicrobial activity of the two methanol extracts from selected marine (Dunaliella salina) and freshwater (Pseudokirchneriella subcapitata) microalgae was tested on the isolated pathogens. Totally, 114 bacterial and 11 fungal strains were isolated, of which Staphylococcus spp. (28.8%) and Pseudomonas aeruginosa (P. aeruginosa) (24.8%) were the major pathogens. Only three Staphylococcus aureus (S. aureus) strains and 11 coagulase-negative Staphylococci showed resistance to methicillin. The two algal extracts showed interesting antimicrobial properties, which mostly inhibited the growth of isolated S. aureus, P. aeruginosa, Escherichia coli, and Klebsiella spp. with MICs range of 1.4 × 10⁹ to 2.2 × 10¹⁰ cells/mL. These results suggest that the two algae have potential as resources for the development of antimicrobial agents.     

Entry Inhibition of Influenza Viruses with High Mannose Binding Lectin ESA-2 from the Red Alga Eucheuma serra through the Recognition of Viral Hemagglutinin

Lectin sensitivity of the recent pandemic influenza A virus (H1N1-2009) was screened for 12 lectins with various carbohydrate specificity by a neutral red dye uptake assay with MDCK cells. Among them, a high mannose (HM)-binding anti-HIV lectin, ESA-2 from the red alga Eucheuma serra, showed the highest inhibition against infection with an EC₅₀ of 12.4 nM. Moreover, ESA-2 exhibited a wide range of antiviral spectrum against various influenza strains with EC₅₀s of pico molar to low nanomolar levels. Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2. Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay. This interaction was effectively suppressed by glycoproteins bearing HM-glycans, indicating that ESA-2 binds to the HA of influenza virus through HM-glycans. Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells. ESA-2 would thus be useful as a novel microbicide to prevent penetration of viruses such as HIV and influenza viruses to the host cells.     

大型海藻养殖对水体DO含量的影响

为了解大型海藻养殖对海水DO含量的影响,明确其在光照、黑暗及光暗交替条件下海水DO含量的变化过程。笔者将取自温州洞头近海养殖的鼠尾藻、羊栖菜带至实验室内进行养殖实验,设置光照（2、6、12 h）、黑暗（2、6、12 h）、光暗交替（1 h 1 h、6 h 6 h、12 h 12 h）处理,测定养殖水体DO含量,对其产氧速率、耗氧速率等进行分析。结果表明：随着光照时间的延长,鼠尾藻、羊栖菜产氧速率都逐渐下降,鼠尾藻的产氧速率比羊栖菜高（P<0.05）;黑暗条件下,鼠尾藻耗氧速率在6 h时达最高288.02 mg/kg DW?h,羊栖菜耗氧速率在2 h时达最高207.46 mg/kg DW?h,鼠尾藻的耗氧速率比羊栖菜高;光暗交替下鼠尾藻的净产氧速率先急剧降低后缓慢升高,短光暗交替周期（1 h 1 h）时净产氧速率最高457.08 mg/kg DW?h。羊栖菜净产氧速率先升高后降低,在中光暗交替周期（6 h 6 h）时最高64.04 mg/kg DW?h。大型海藻养殖时随着光暗环境的交替进行,不断发生着光合产氧、暗呼吸耗氧的转换,总体而言海藻养殖提高了水体DO含量。大型海藻养殖的生态、社会价值显著,建议大力推广     

Photosynthetic pigments in soils from northern Victoria Land (continental Antarctica) as proxies for soil algal community structure and function

Although soil algae are among the main primary producers in most terrestrial ecosystems of continental Antarctica, there are very few quantitative studies on their relative proportion in the main algal groups and on how their distribution is affected by biotic and abiotic factors. Such knowledge is essential for understanding the functioning of Antarctic terrestrial ecosystems. We therefore analyzed biological soil crusts from northern Victoria Land to determine their pH, electrical conductivity (EC), water content (W), total and organic C (TC and TOC) and total N (TN) contents, and the presence and abundance of photosynthetic pigments. In particular, the latter were tested as proxies for biomass and coarse-resolution community structure. Soil samples were collected from five sites with known soil algal communities and the distribution of pigments was shown to reflect differences in the relative proportions of Chlorophyta, Cyanophyta and Bacillariophyta in these sites. Multivariate and univariate models strongly indicated that almost all soil variables (EC, W, TOC and TN) were important environmental correlates of pigment distribution. However, a significant amount of variation is independent of these soil variables and may be ascribed to local variability such as changes in microclimate at varying spatial and temporal scales. There are at least five possible sources of local variation: pigment preservation, temporal variations in water availability, temporal and spatial interactions among environmental and biological components, the local-scale patchiness of organism distribution, and biotic interactions.     

水生藻类的环境指示作用

为了方便有效地监测水环境中有氮磷污染物、重金属、农药及其他有机污染物等,笔者研究了水生藻类对水体环境中相应污染物的敏感性和耐受性,以及污染物对水域生态系统中藻类种群结构所造成的影响,分析了污染物对水生藻类的毒理和富集等,获得了大量数据。结果表明,水生藻类对一些水环境污染物具有较好的指示作用,该方法便于直观快速地调查分析相应水体的污染情况。     

卡特兰水培技术研究

为研究名贵兰花的水培技术,促进水培兰花的生产与消费,以兰科卡特兰为试材,从卡特兰水生根系诱导,营养液培养,筛选出水培卡特兰诱导根系的最适宜的NAA浓度和营养液配方,在培养的过程中,防治根腐烂和水藻的生成。结果表明,低浓度NAA（5mg/L）对诱导水生根系具有促进作用;KC营养液是水培卡特兰较好的营养液;加强根部通气有利于防止卡特兰根系的腐烂,在培养过程中添加2～3滴含氯霉素的滴眼液有助于防止藻类的生长。     

鲢鳙鱼和藻类治理关系的初步研究

2008年7月至9月在蠡湖设置宝界桥和石塘桥两个实验点进行鲢鳙鱼和藻类治理关系的初步研究,采用常规生物学方法,测定了鲢鳙鱼的体长、体重、消化腺指数、肠长指数、食物充塞度、肥胖度系数、饱满度等参数。实验表明微囊藻和颤藻在鲢鳙鱼体内得不到完全消化,但可以破坏藻类的存在形式,一定程度上也说明鲢鳙鱼对于微囊藻和颤藻的治理有一定的作用。     

淡水浮游藻类在池塘养殖中的负面影响

淡水浮游藻类是鱼类和其他经济动物的直接或间接的饵料基础,是水域原始生产者,在决定水域生产性能上有重要意义。但是近几年的深入研究表明,淡水浮游藻类在池塘养殖中也存在着一些负面影响。     

Algal Lectins as Potential HIV Microbicide Candidates

The development and use of topical microbicides potentially offers an additional strategy to reduce the spread of the Human Immunodeficiency Virus (HIV). Carbohydrate-binding agents (CBAs) that show specificity for high mannose carbohydrates on the surface of the heavily glycosylated envelope of HIV are endowed with potent anti-HIV activity. In fact, a number of algal lectins such as cyanovirin-N, microvirin, microcystis viridis lectin, scytovirin, Oscillatoria agardhii agglutinin and griffithsin are considered as potential microbicide candidates to prevent the sexual transmission of HIV through topical applications. They not only inhibit infection of cells by cell-free virus but they can also efficiently prevent virus transmission from virus-infected cells to uninfected CD4(+) target T-lymphocytes and DC-SIGN-directed capture of HIV-1 and transmission to CD4(+) T lymphocytes. This review focuses on the structural properties and carbohydrate specificity of these algal lectins, their antiviral activity against HIV and several other enveloped viruses, their safety profile and viral resistance patterns.