一种适用于研究切应力对蓝藻细胞活性影响的实验装置

目的设计一种用于进行切应力对蓝藻细胞活性影响的相关实验研究装置。方法针对现有流体切应力实验装置容积小、切应力不稳定、难以进行定量分析和持续性差等缺陷进行设计优化,成功设计出1个有效容积400~700 mL、误差小于13.8%、能产生定量均匀切应力场且可进行至少96 h跟踪观测的切应力发生装置。结果通过对铜绿微囊藻的实验研究,证实所设计装置产生的切应力可对铜绿微囊藻细胞的活性产生显著的影响。结论设计的实验装置是进行流体切应力对蓝藻细胞活性影响相关研究的有效仪器。     

Isolation of a non-steroidal contragestative agent from Sri Lankan marine red alge, Gelidiella acerosa

This study reports the isolation of a non-steroidal contrag-estative agent from the Sri Lankan marine red alga, Gelidiella acerosa. One-hundred grams of MeOH-CH₂Cl₂ (1:1) crude extract of G. acerosa was initially partitioned into hexane, CH₂Cl₂ and EtOAc, respectively, using the modified Kupchan scheme. At each separation step, all the resulting fractions were tested for contragestative effects in pregnant rats. The fertility was assessed in terms of the number of viable implants following oral administration of fractions (co-precipitated with polyvinylpyrrolidone), on day 1 through day 7 of pregnancy. The hexane fraction with highest activity was subjected to gel filtration through Sephadex LH-20, vacuum liquid chromatography over TLC-grade silica, two open-column chromatography runs over silica gel (60–120 mesh), and HPLC to isolate the active component. Nuclear magnetic resonance and infrared spectroscopic analysis revealed that the contragestative agent of G. acerosa is a sphingosine derivative.     

Physical maps of the two circular plastid DNA molecules of the brown algaPylaiella littoralis (L.) Kjellm

Summary Two circular molecules of different sizes, both belonging to the chloroplast DNA of the brown algaPylaiella littoralis, have been observed by electron microscopy (Dalmon et al. 1983). Clone banks representing 86% of the small chloroplast circular DNA molecule (58 kbp) and 69% of the large circular DNA molecule (133 kbp) have been established and used as tools in the construction of physical maps. Two rDNA operons have been mapped in a very small inverted repeat on the large circular molecule. One 16S rRNA pseudogene and one split 23S rRNA gene have been mapped on the small DNA molecule, far apart from each other. Using heterologous probes, genes for ten different proteins have also been located on these maps. Their arrangement on the large molecule is different from that found in higher plants and algae. Probes fromrbcL, psbA andrps19 genes hybridize to several separated fragments. Two of them (psbA andrps19) hybridize to both types of molecules.     

A review on toxic and harmful algae in greek coastal waters (e. Mediterranean sea)

The Greek coastal waters are subjected to harmful algal bloom (HAB) phenomena due to the occurrence of species characterized as toxic (TX), potentially toxic (PT), and non-toxic, high biomass (HB) producers causing harm at multiple levels. The total number of (TX), (PT) and (HB) algae reported in this work are 61, but only 16 species have been associated with the occurrence of important HABs causing damage in the marine biota and the water quality. These phenomena are sporadic in time, space and recurrence of the causative species, and are related to the anthropogenically-induced eutrophication conditions prevailing in the investigated areas.     

藻酸双酯钠局部注射治疗眼睑黄色瘤

目的：观察藻酸双酯钠治疗眼睑黄色瘤的效果.方法：对病变组织皮内注射藻酸双酯钠,治疗45例82眼进行回顾性总结.结果：治愈75眼,好转3眼,无效4眼.无感染、瘢痕等并发症.结论：藻酸双酯钠治疗眼睑黄色瘤操作简便、损伤小、安全、有效.     

Recreational exposure to microcystins during algal blooms in two California lakes

We conducted a study of recreational exposure to microcystins among 81 children and adults planning recreational activities on either of three California reservoirs, two with significant, ongoing blooms of toxin-producing cyanobacteria, including Microcystis aeruginosa (Bloom Lakes), and one without a toxin-producing algal bloom (Control Lake). We analyzed water samples for algal taxonomy, microcystin concentrations, and potential respiratory viruses (adenoviruses and enteroviruses). We measured microcystins in personal air samples, nasal swabs, and blood samples. We interviewed study participants for demographic and health symptoms information. We found highly variable microcystin concentrations in Bloom Lakes (<10 μg/L to >500 μg/L); microcystin was not detected in the Control Lake. We did not detect adenoviruses or enteroviruses in any of the lakes. Low microcystin concentrations were found in personal air samples (<0.1 ng/m³ [limit of detection]-2.89 ng/m³) and nasal swabs (<0.1 ng [limit of detection]-5 ng). Microcystin concentrations in the water-soluble fraction of all plasma samples were below the limit of detection (1.0 μg/L). Our findings indicate that recreational activities in water bodies that experience toxin-producing cyanobacterial blooms can generate aerosolized cyanotoxins, making inhalation a potential route of exposure. Future studies should include collecting nasal swabs to assess upper respiratory tract deposition of toxin-containing aerosols droplets.     

A cytotoxic hydroperoxy sterol from the brown alga,Nizamuddinia zanardinii

Background

The marine environment is a unique source of bioactive natural products, of which Nizamuddinia zanardinii is an important brown algae distributed in Oman Sea. Literature revealed that there is no report on phytochemistry and pharmacology of this valuable algae.

Methods

Bioguided fractionation of the methanolic extract of Nizamuddinia zanardinii, collected from Oman Sea, led to the isolation of a hydroperoxy sterol. Its structure was determined by analysis of the spectroscopic data as 24-hydroperoxy-24-vinyl cholesterol (HVC). In vitro cytotoxic activity of this compound was evaluated against HT29, MCF7, A549, HepG2 and MDBK cell lines.

Results

Although 24(R)-hydroproxy-24-vinylcholesterol has been previously reported from Sargassum and Padina species, it is the first report on the presence of this compound from N. zanardinii. This compound exhibited cytotoxicity in all cell lines (IC₅₀, 3.62, 9.09, 17.96, 32.31 and 37.31 μg/mL respectively). HVC was also evaluated for apoptotic activity and demonstrated positive results in terminal deoxynucleotidyl transferase dUTP Nick End labeling (TUNEL) assay suggesting it a candidate for further apoptotic studies.

Conclusions

Nizamuddinia zanardinii, a remarkable brown algae of Oman Sea, is a good source of hydroproxy sterols with promising cytotoxic on various cell lines particularly human colon adenocarcinoma.     

Exopolymer alteration of physical properties of sea ice and implications for ice habitability and biogeochemistry in a warmer Arctic

The physical properties of Arctic sea ice determine its habitability. Whether ice-dwelling organisms can change those properties has rarely been addressed. Following discovery that sea ice contains an abundance of gelatinous extracellular polymeric substances (EPS), we examined the effects of algal EPS on the microstructure and salt retention of ice grown from saline solutions containing EPS from a culture of the sea-ice diatom, Melosira arctica. We also experimented with xanthan gum and with EPS from a culture of the cold-adapted bacterium Colwellia psychrerythraea strain 34H. Quantitative microscopic analyses of the artificial ice containing Melosira EPS revealed convoluted ice-pore morphologies of high fractal dimension, mimicking features found in EPS-rich coastal sea ice, whereas EPS-free (control) ice featured much simpler pore geometries. A heat-sensitive glycoprotein fraction of Melosira EPS accounted for complex pore morphologies. Although all tested forms of EPS increased bulk ice salinity (by 11-59%) above the controls, ice containing native Melosira EPS retained the most salt. EPS effects on ice and pore microstructure improve sea ice habitability, survivability, and potential for increased primary productivity, even as they may alter the persistence and biogeochemical imprint of sea ice on the surface ocean in a warming climate.