OBJECTIVE: To explore the quantity and distribution of diatoms in main rivers and lakes in Xicheng, Dongcheng, Chaoyang, Haidian, Fengtai and Shijingshan Districts of the city of Beijing. METHODS: Water samples were examined through the method of disorganizing, which were collected from 16 rivers and lakes in the central city of Beijing in September and October 2011. Diatom species and proportions of water samples were analyzed using DotSlide microscope station. RESULTS: A total of 10 species of diatoms were detected. Cyclotella, Synedra and Melosira etc. were found to be the dominant species via quantitative analysis. Significant differences were observed for diatom species and proportions among the different rivers and lakes. Melosira was found to be the dominant species in the Chang River; Synedra, in the Zhuan River, the Kunyu River and the Taoranting Park; Cyclotella, in the East Moat River, the Ba River, the Liangshui River and the Yongding River; and Navicula, in the Liangma River; Nitzschia, in the diversion canal of the Yongding River. CONCLUSION The features of distribution of diatoms in the central city of Beijing are outlined. The morphological and relative constituent ratio database of diatoms are established in central city of Beijing.
Biodiversity ; China ; Cities ; Diatoms/isolation & purification* ; Ecosystem ; Forensic Medicine/methods* ; Fresh Water/analysis* ; Phytoplankton/isolation & purification* ; Rivers ; Species Specificity

To evaluate the public health risk of exposure to microcystins in fish food in China, the distribution pattern of microcystin-LR and microcystin-RR in various organs (liver, intestine, kidney, muscle and lipid) of the dominant freshwater phytoplanktivorous fish Hypophthalmichthys molitrix in Hangzhou, China's Tiesha River was investigated with the method of HPLC-ESI-MS analysis. The distribution of microcystins was different in the fish organs and the major total microcystins (microcystin-LR and microcystin-RR) were present in the intestines (6.49 micro g/g fresh weight), followed by the livers (4.52 micro g/g fresh weight) and the muscles (2.86 micro g/g fresh weight). Microcystins were detected in kidneys (1.35 micro g/g fresh weight), but not detected in lipid. The results suggested that the mean daily intake from fish was 0.03 micro g/kg body weight which was very close to the recommended WHO tolerable daily intake (TDI) level of 0.04 micro g/kg body weight per day, and local people were warned they may have health risk if they consumed fish from the river.
Animals ; Carps ; metabolism ; parasitology ; Fresh Water ; analysis ; parasitology ; Microcystins ; metabolism ; Organ Specificity ; Phytoplankton ; metabolism ; Risk Assessment ; methods ; Risk Factors ; Tissue Distribution ; Water Pollutants, Chemical ; analysis

OBJECTIVETo investigate the hispathological characteristics and antioxidant responses in liver of silver carp after intraperitoneal administration of microcystins (MCs) for further understanding hepatic intoxication and antioxidation mechanism in fish.

METHODSPhytoplanktivorous silver carp was injected intraperitoneally (i.p.) with extracted hepatotoxic microcystins (mainly MC-RR and -LR) at a dose of 1000 microg MC-LReq./kg body weight, and liver histopathological changes and antioxidant responses were studied at 1, 3, 12, 24, and 48 h, respectively, after injection.

RESULTSThe damage to liver structure and the activities of hepatic antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxide (GPX) were increased in a time-dependent manner.

CONCLUSIONIn terms of clinical and histological signs of intoxication and LD50 (i.p.) dose of MC-LR, silver carp appears rather resistant to MCs exposure than other fishes. Also, the significantly increased SOD activity in the liver of silver carp suggests a higher degree of response to MCs exposure than CAT and GPX.

Animals ; Antioxidants ; metabolism ; Carps ; metabolism ; Catalase ; metabolism ; Glutathione Peroxidase ; metabolism ; Injections, Intraperitoneal ; Liver ; drug effects ; enzymology ; pathology ; Microcystins ; administration & dosage ; isolation & purification ; pharmacology ; Phytoplankton ; physiology ; Reactive Oxygen Species ; metabolism ; Superoxide Dismutase ; metabolism ; Survival Analysis ; Time Factors

Astaxanthin is widely applied as a nutraceutical, pharmaceutical, and aquaculture feed additive because of its high antioxidant activity. Haematococcus pluvialis is a microalgal species that can largely accumulate astaxanthin under adverse environmental conditions. Here we review the research progress of astaxanthin biosynthesis in H. pluvialis, including the induction and regulation of massive astaxanthin, the relationship between astaxanthin synthesis, photosynthesis and lipid metabolism.
Chlorophyceae ; Chlorophyta ; Microalgae ; Xanthophylls

Microalgae are a group of photosynthetic microorganisms, which have the general characteristics of plants such as photosynthesis, and some species have the ability of movement which resembles animals. Recently, it was reported that microalgae cells can be engineered to precisely deliver medicine-particles and other goods in microfluidic chips. These studies showed great application potential in biomedical treatment and pharmacodynamic analysis, which have become one of the current research hotspots. However, these developments have been rarely reviewed. Here, we summarized the advances in manageable movement exemplified by a model microalgae Chlamydomonas reinhardtii based on its characteristics of chemotaxis, phototaxis, and magnetotaxis. The bottlenecks and prospects in the application of microalgae-based tactic movement were also discussed. This review might be useful for rational design and modification of microalgal manageable movement to achieve targeted transport in medical and other fields.
Chlamydomonas reinhardtii ; Microalgae ; Microfluidics ; Photosynthesis

Microalgae have been identified as promising candidates for biorefinery of value-added molecules. The valuable products from microalgae include polyunsaturated fatty acids and pigments, clean and sustainable energy (e.g. biodiesel). Nevertheless, high cost for microalgae biomass harvesting has restricted the industrial application of microalgae. Flocculation, compared with other microalgae harvesting methods, has distinguished itself as a promising method with low cost and easy operation. Here, we reviewed the methods of microalgae harvesting using flocculation, including chemical flocculation, physical flocculation and biological flocculation, and the progress and prospect in bio-flocculation are especially focused. Harvesting microalgae via bio-flocculation, especially using bio-flocculant and microalgal strains that is self-flocculated, is one of the eco-friendly, cost-effective and efficient microalgae harvesting methods.
Biofuels ; Biomass ; Flocculation ; Microalgae ; growth & development

Intense utilization and mining of fossil fuels for energy production have resulted in environmental pollution and climate change. Compared to fossil fuels, microalgae is considered as a promising candidate for biodiesel production due to its fast growth rate, high lipid content and no occupying arable land. However, monocultural microalgae bear high cost of harvesting, and are prone to contamination, making them incompetent compared with traditional renewable energy sources. Co-culture system induces self-flocculation, which may reduce the cost of microalgae harvesting and the possibility of contamination. In addition, the productivity of lipid and high-value by-products are higher in co-culture system. Therefore, co-culture system represents an economic, energy saving, and efficient technology. This review aims to highlight the advances in the co-culture system, including the mechanisms of interactions between microalgae and other microorganisms, the factors affecting the lipid production of co-culture, and the potential applications of co-culture system. Finally, the prospects and challenges to algal co-culture systems were also discussed.
Biofuels ; Biomass ; Coculture Techniques ; Flocculation ; Microalgae

Filamentous microalga Tribonema sp. has the advantages of highly resistance to zooplankton-predation, easy harvesting, and high cellular lipid content, in particular large amounts of palmitoleic acid (PA) and eicosapentaenoic acid (EPA). Therefore, Tribonema sp. is considered as a promising biomass feedstock to produce biodiesel and high-value products. In this work, we studied the effect of different concentrations of nitrogen (NaNO₃: 255-3 060 mg/L), phosphorus (K₂HPO₄: 4-240 mg/L), iron ((NH₄)₃FeC₁₂H₁₀O₁₄: 0.6-12 mg/L) and magnesium (MgSO₄: 7.5-450 mg/L) on the biomass, lipid content, and fatty acid composition of Tribonema sp. FACHB-1786, aiming at enhancing cell lipid productivity. The growth of Tribonema sp. had a positive correlation with the concentration of magnesium, and the maximum biomass of Tribonema sp. (under the condition of 450 mg/L MgSO₄) was 8.09 g/L, much greater than those reported in previous studies using the same and other Tribonema species under autotrophic conditions. Different nitrogen concentrations exerted no significant effect on algal growth (P > 0.05), but a higher nitrogen concentration resulted in a greater amount of lipid in the cells. The maximum volumetric productivities of total lipids (319. 6 mg/(L·d)), palmitoleic acid (135.7 mg/(L·d)), and eicosapentaenoic acid (24.2 mg/(L·d)) of Tribonema sp. were obtained when the concentrations of NaNO₃, K₂HPO₄, (NH₄)₃FeC₁₂H₁₀O₁₄, and MgSO₄ were 765 mg/L, 80 mg/L, 6 mg/L, and 75 mg/L, respectively. This study will provide a reference for substrate optimization for Tribonema sp. growth and lipid production.
Biofuels ; Biomass ; Lipids ; Microalgae ; Nitrogen ; Stramenopiles

Botryococcus braunii is a unique colonial green microalga and a great potential renewable resource of liquid fuel because of its ability to produce lipids. Due to the dense cell colonies and rigidly thick cell wall of B. braunii, the traditional Nile red method is usually of low sensitivity and bad repeatability and hard for the determination of lipid content in the cells. By dispersing the colony with ultrasonic, assisting permeation of Nile red across the cell wall with dimethyl sulfoxide and optimizing the staining conditions, we established an improved detection method. The details were as follows: after the colonial algal sample was treated by ultrasonic at 20 kHz for 20 s, 100 W transmitting power and with 1 s on/1 s off intermittent cycle, the equivoluminal 15% (V/V) dimethyl sulfoxide and 3 microg/mL Nile red were successively added and mixed evenly, then the staining system was incubated in dark at 40 degrees C for 10 min, and subsequently was measured by fluorescence spectroscopy detection with an excitation wavelength of 490 nm. Compared with the traditional method, the improved one not only had higher detection sensitivity which was increased by 196.6%, but also had obviously better detection repeatability whose characteristic parameter - relative standard deviation (RSD) was decreased from 10.91% to 1.84%. Therefore, the improved method could provide a rapid and sensitive detection of lipid content for B. braunii breeding and cultivation.
Chlorophyta ; chemistry ; Lipids ; analysis ; Microalgae ; chemistry ; Spectrometry, Fluorescence ; methods ; Ultrasonics

Microalgae is a single-cell organism with the characteristics of high light energy utilization rate, fast growth rate, high-value bioactive components and high energy material content. Therefore, microalgae has broad application prospects in food, feed, bioenergy, carbon sequestration, wastewater treatment and other fields. In this article, the microalgae biotechnology development in recent years were fully consulted, through analysis from the literature and patent. The progress of microalgal biotechnology at home and abroad is compared and discussed. Furthermore, the project layout, important achievements and development bottlenecks of microalgae biotechnology in our country were also summarized. At last, future development directions of microalgae biotechnology were discussed.
Bibliometrics ; Biofuels ; Biomass ; Biotechnology ; trends ; Microalgae ; metabolism ; Waste Water