ABSTRACT
Ice microalgae, which inhabit in the extreme conditions of polar marine environment, not only play an important role in Antarctica ecosystem but also show broad prospects in basic research and application. Ice microalgae have the specific physiological and metabolic properties that are responsible for their adaptation and acclimation to the special polar conditions. Based on the references in the recent twenty years and the partial research results of author's, the ice microalgae composition and distribution, and the application in bait, unsaturated fatty acid, anti-freezing proteins, UV-absorbing pigments and other active substances are reviewed. It is expected to provide references for the research and active substance exploitations of ice microalgae.
ABSTRACT
'Ozone hole' , which cause a great increment of the UV radiation to the earth surface, is a exclusive phenomena over the Antarctic. After living in high UV radiation for a long time , plankton in the Antarctic have produced many anti-radiation active substances. In this article, the properties, configurations, functions, etc. of anti-radiation active substances in algae, bacteria and fungi in the Antarctic wen: summarized. At the same time, significative illuminations on the studies and utilization of anti-radiation and anti-tumour active substances are expected.
ABSTRACT
To explore the effects of dietary conjugated linoleic acid(CLA) on body fat accumulation in male Wistar rats. The obese rat model was established by feeding high lipid forage. The rats were fed a semi-purified diet containing 0.5,1.0,3.0g?kg -1 CLA for 36 days. Low dose group, middle dose group and high dose group all could remarkably reduce the gain of body weight. Low dose group could reduce the body adipose, middle and high dose group could remarkably decrease the body adipose. There were significant differences in the fat and protein contents in the rats thigh between the control group and the group fed high dose CLA. These results suggested that CLA can reduce the body fat in obese Wistar rats.
ABSTRACT
Objective To study on algicidal bioactive substances from mangrove bacteria and its algicidal effect on red tide algae Alexandriam tamarense.Methods A red algicidal bioactive substance in Guangxi mangrove bacteria was isolated and purified by Silica-gel Column Chromatography,and its structure was determined on the basis of UV,IR,1H NMR,13C NMR and HREIMS spectroscopic analyses and comparison with the literatures.Its algicidal affect was primarily studied in this paper.Results and Conelusion The results showed that the red algicidal bioactive substance was prodigiosin,which had an inhibitory effect on the cells growth of Alexandrium tamarense,and the inhibitory effect increased with the increase of prodigiosin concentration.The prodigiosin stimulated the production of MDA and reduced the content of sulfhydryl group.In addition,plasma membrane permeability of leaked cell solution was increased.These indicated the extinguishing mechanism: the cell membrane was damaged followed by the inhibition of the cell growth.
ABSTRACT
A yeast strain Rhodotorula sp.NJ-298,which was isolated from antarctic sea-ice,could produce carotenoids pigment,and the total production was 1986?g?g~(-1).UV-visible spectrum and LC/MS analysis indicated astaxanthin was the major component of the carotenoids,and HPLC analysis showed its content accounted for 81.9 % of total carotenoids productoin.Maximum astaxanthin production 6506 ?g?L~(-1) was obtained when the yeast was grown at steady-state phase.Optimum temperature for the strain grow was at 8℃,and sodium acetate and peptone were the best carbon and nitrogen sources for the astaxanthin production.Moreover,the pigment had strong activity of scavenging free radicals,and the IC_(50) was 0.40 ?g?mL~(-1) by DPPH assay.
ABSTRACT
In this paper,the method about hydrolysis of fish oil with lipases for concentrating DHA(docosahexenoic acid) in glycerides was studied.Six lipases were screened with comparing the activities of hydrolysis of fish oil.Candida lipalytica Lipase is resistant to generating DHA in fish oil.The Effects of the quantity of lipases,the emulgent,hydrolysis time,temperature in the process,the ratio of oil to water were studied.The optimum conditions for the hydrolysis of fish oil are 12 hours of hydrolysis under 45℃,with 300 u?g -1 .The emulgent was and the ratio of oil to water was 0.4 mL?g -1 .Under these conditions,the content of DHA in glyceride were concentrated from 18.7% to 34.0%.But the EPA content remained close to that of fish oil.The DHA glyceride containing triglyceride,diglyceride and monoglyceride was identified by IR spectrum combining with separation of HPLC.
ABSTRACT
Objective To study on glutathione and glutathione-related enzymes of Antarctic ice microalgae.Methods Glutathione(GSH) content,glutathione produce ability(GPA) and glutathione reductase(GR) activity in 24 kinds of Antarctic ice microalgae were assessed using the spectrophotometer methods.Results GSH content of Cyanophyceae B-1 was highest.Total GSH yields of Antarctic ice microalgae Chlamydomonas sp.ICE-L and Berkeleya rutilans GJ01 were in the top two positions.GPA in most Antarctic ice microalgae was higher than that in mesophilic green algae,and only in two ice microalgae was lower than that in Phaeodactylum tricornutum.GR activities of Antarctic ice microalgae Berkeleya rutilans GJ01 and Chlamydomonas sp.ICE-L were greater than that of the control microalgae.Conclusion It is possible that Antarctic ice microalgae will become a new resource of GSH.
ABSTRACT
Objective To study on quenching free radical substances in antarctic ice alga.Methods Antarctic ice alga Berkeleya rutilans H-15 used as material,complete experiment of preparation free radical scavenging substances was established.All of these include the extraction of active substances by methanol,then pursuing and determination of the separation effect and change of active substances by DPPH and Godin method;the primary separation and purification by silica gel 60 column chromatogram;the farther purification by Sephadex LH column chromatogram and the purity determination of compound by HPLC.The type of compound and functional group of high pure compound were determined by the IR spectrum,HPLC-MS.Results One pure compound with strong activity was obtained from Berkeleya rutilans H-15,and it was confirmed to belong to phenol derives by analysis of IR spectrum and HPLC-MS.Conclusion It was completely feasible to find and acquire quenching free radical substances in antarctic ice alga,which initiated a new way to obtain natural antioxidant active substances from antarctic microorganism.
ABSTRACT
Objective To study on bioactive chemical compounds against ultraviolet irradiation in antarctic ice microalgae.Methods Four kinds of Antarctic ice microalgae were cultured under the conditions of low temperature,illumination,UV-A and UV-B irradiation.The chemical compounds were extracted by methanol and analyzed by spectrophotometer and HPLC/MS.The molecular structures were elucidated according to these data.The chemical compounds were irradated by sunshine to observe the speed of degradation and to estimate the bioactivity.Results There were five active compounds in Chlorophyceae L-4 and 7 active compounds in Diatom HF-9,in which 6 compounds belong to MAAs(mycosporine-like amino acids) and were of more bioactivity against ultraviolet irradiation.Conclusion MAAs from of Antarctic ice microalgae play an important role in resisting ultraviolet irradiation.