In this study, molecular weight controllable degradation of algal Laminaria japonica polysaccharides(LPS) was investigated by ultrasound combined with hydrogen peroxide. Three main factors, i.e., ultrasonic power(A), ...In this study, molecular weight controllable degradation of algal Laminaria japonica polysaccharides(LPS) was investigated by ultrasound combined with hydrogen peroxide. Three main factors, i.e., ultrasonic power(A), ultrasonic time(B), and H_2O_2 concentration(C) were chosen for optimizing parameters by employing three-factors, three-levels BBD. The influence of degradation on structure change and antioxidant activities was also investigated. A second-order polynomial equation including molecular weight(Y) of Laminaria japonica polysaccharides and each variable parameter, i.e., ultrasonic power(A), ultrasonic time(B), and H_2O_2 concentration(C), was established: Y=20718.67-4273.13A-4000.38B-1438.75C+2333.25AB+1511.00AC+873.00BC+2838.29A^2 + 2490.79B^2+873.04C^2. The equation regression coefficient value(R^2 = 0.969) indicated that this equation was valid. The value of the adjusted determination coefficient(adjusted R^2 = 0.914) also confirmed that the model was highly significant. The results of selected experimental degradation conditions matched with the predicted value. FT-IR spectra revealed that the structures of LPS before and after degradation were not significantly changed. Antioxidant activities of LPS revealed that low Mws possessed stronger inhibitory than the original polysaccharides. The scavenging effects on superoxide radicals was the highest when IC50 of crude LPS was 4.92 mg mL^(-1) and IC50 of Mw 18.576 KDa was 1.02 mg mL^(-1), which was fourfold higher than initial polysaccharide.展开更多
The parthenogenesis and natural doubling of chromosomes in wild type female gametophytes of Laminaria japonica were studied. The results indicate that not all the female gametophytes from the wild type hybrid parent c...The parthenogenesis and natural doubling of chromosomes in wild type female gametophytes of Laminaria japonica were studied. The results indicate that not all the female gametophytes from the wild type hybrid parent can propagate through parthenogenesis. Most parthenosporophytes can mature, their spores germinate into gametophytes, the latter then developed into female sporophytes. To form these parthenosporophytes the natural doubling of chromosomes occurred mainly at the first and second cell divisions of the spores. It is thus considered that the parthenogenesis of L. japonica is inheritable and the relative genes link closely with the genes controlling the natural doubling of chromosomes and the female determination.展开更多
This study on the effects of ultrasonic treatment on female gametophytes of Laminariajaponica showed that:1. Ultrasonic treatment had shortening effect on filaments of female gametophytes. Within certainperiod of time...This study on the effects of ultrasonic treatment on female gametophytes of Laminariajaponica showed that:1. Ultrasonic treatment had shortening effect on filaments of female gametophytes. Within certainperiod of time, the average length of filamentous female gametophytes was shortened.2. Ultrasonic treatment had emptying effect on cells. The number of empty cells increased with timeof treatment. Ultrasonic treatment had harmful effect on cells.3. Ultrasonic treatment could break down cell walls. The combination of frequency of 20 kHz, out-put of 15 W, 40 s and 60 s of treatment was best for this purpose. After ultrasonic treatment, the regner-ation of female gametophytes into sporophytes was effected. Female gametophytes could not recover aftertoo long period of treatment.展开更多
The cultivation of the first filial generation of monoploid gametophyte clones of different Laminaria species (hybrid Laminaria) is an effective way of utilizing heterozygous vigor (heterosis). A female gametophyte cl...The cultivation of the first filial generation of monoploid gametophyte clones of different Laminaria species (hybrid Laminaria) is an effective way of utilizing heterozygous vigor (heterosis). A female gametophyte clone of L. japonica and a male gametophyte clone of L. longissima were hybridized, generating Dongfang No.2 hybrid Laminaria. The parentage of this hybrid Laminaria was determined using AFLP of total DNA, SNP of the ITS region of ribosomal RNA transcription unit and microsatellite DNA variation at two loci. In addition to 167 AFLP bands shared by Dongfang No.2, L. japonica and L. longissima, Dongfang No.2 hybrid Laminaria shared another 70 and 55 bands with L. japonica and L. longissima, respectively, which were obviously more than 11 bands shared by L. japonica and L. longissima. Dongfang No.2 held both ‘T’ and ‘C’ at position 847 of the ITS region, while ‘T’ at this position was specific for L. japonica and ‘C’ for L. longissima, respectively. Dongfang No.2 also held the microsatellite DNA alleles of two parents together at two microsatellite DNA marker loci. These observations clearly proved that Dongfang No.2 is a true hybrid of L. japonica and L. longissiuma. Unfortunately, the origin of the chloroplast of Dongfang No.2 was not determined based on the variation of RuBisCo spacer. More sequence variants of both ITS region and RuBisCo spacer were identified in Dongfang No.2 and most of them did not exist in either L. japonica or L. longissima. The unexpected variants may be due to the mutation of ga- metophyte clones occurring during their vegetative amplification.展开更多
Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m-2 s-1 ...Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m-2 s-1 for 3 weeks were en- capsulated in calcium alginate beads. The beads were dehydrated in 0.4 molL-1 sucrose prepared with seawater for 6 h, desiccated in an incubator set at 10℃ and 70% relative humidity for 4 h, pre-frozen at either ?40℃ or ?60℃ for 30 min, and stored in liquid nitrogen for >24 h. As high as 43% of survival rate was observed when gametophytes were thawed by placing the beads in 40℃ seawater and re-hydrated in 0.05 molL-1 citrate sodium prepared using 30‰ NaCl 7 d later. More cells of male gametophytes sur- vived the whole procedure in comparison with female gametophytes. The cells of gametophytes surviving the preservation were able to grow asexually and produce morphologically normal sporophytes.展开更多
We collected the diseased blades of Laminaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified...We collected the diseased blades of Laminaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as Alteromon as espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and to find the possibly effective mechanism. Results showed that: (1) The blades of L. japonica exhibited symptoms of lesion, bleaching and deterioration when infe cted by the bacterium, and their growth and photosynthesis were dramatically sup pressed. At the same time, the reactive oxygen species(ROS) generation enhanced obviously, and the relative membrane permeability increased significantly. The c ontents of malonaldehyde(MDA) and free fatty acid in the microsomol membrane gre atly elevated, but the phospholipid content decreased. Result suggested an obvio us peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. (2) The simultaneous assay on the antioxidant enzyme activiti es demonstrated that superoxide dismutase (SOD) and catalase(CAT) increased grea tly when infected by the bacterium, but glutathione peroxidase(Gpx) and ascorbat e peroxidase(APX) did not exhibit active responses to the bacterium throughout t he experiment. (3) The histomorphological observations gave a distinctive eviden ce of the severity of the lesions as well as the relative abundance in the bacte rial population on the blades after infection. The bacterium firstly invaded int o the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L. japonica.展开更多
For the population genetics analysis of the naturally grown brown seaweed Laminaria japonica (Laminariales,Phaeophyta) sampled from Dalian,Yantai,Weihai,Rongcheng and Qingdao in China,ten primers were employed to prod...For the population genetics analysis of the naturally grown brown seaweed Laminaria japonica (Laminariales,Phaeophyta) sampled from Dalian,Yantai,Weihai,Rongcheng and Qingdao in China,ten primers were employed to produce 88 bands as revealed by randomly amplified polymorphic DNA (RAPD) markers,and all these bands were polymorphic.According to these band patterns,there were 94 distinct phenotypes occurred in 100 samples indicating the high heterozygosity of this kelp.Dalian population samples showed the highest percentage of polymorphism (71.67%),and also the higher diversity estimated on the basis of the Shannon’s index (8.498),suggesting that this population could be chosen as the best resource for genetic breeding.The highest diversity of Yantai population possibly resulted from the introduction of L.longissima used for interspecific cross breeding with L.japonica cultivated in China.From Dalian southwards to Qingdao,the genetic variation of the five populations became less with a decrease in latitude,possibly due to the natural selection especially of high temperature.The genetic distance (Φ ST values) of the five populations was a little significantly correlated with the geographical distance (r=0.496) at P =0.05 by Mantel’s test.Weihai,Rongcheng and Yantai populations were closely grouped genetically together by Neighbor-joining cluster analysis probably in that the dispersal of the kelp by propagules more easily occurring in the range of relatively short distance.The analysis of molecular variance (AMOVA) also demonstrated that the relatively higher variation occurred among populations (71.49%) at an extremely significant level (P <0.000 1).All these evidence showed that there was a relatively distinct genetic differentiation among the sampled kelp populations,and L.japonica grown in China was also rather heterozygous in heredity.展开更多
Laminaria gametophyte was greatly influenced by light in its growth and development. Using light-emitting diodes (LED) as blue and red light sources, we analyzed the light effect on gametophytes devel- opment of Lamin...Laminaria gametophyte was greatly influenced by light in its growth and development. Using light-emitting diodes (LED) as blue and red light sources, we analyzed the light effect on gametophytes devel- opment of Laminaria japonica Aresch. The gametophytes were obtained from zoospores collected in April, May, July, 2003 and September, 2004. We found that the growth of gametophytes was stimulated by increasing inten- sity of blue light (BL) and red light (RL) illumination, of which BL was obviously stronger than that of RL. The fertilization of gametophytes depended largely on BL, and only sufficient BL illumination could take the repro- ductive effect. In addition, we noticed that there was a significant difference in light responses for gametophytes developed from zoospore collected in different times. For zoospores released in April, under BL1 (73.90 μmol photons/m·s), the unicellular female gametophytes and multi-cellular male gametophytes produced eggs and sperms respectively, and further developed towards sporophytes. However, for gametophytes developed in May, July or September, they became multi-cellular and never formed oogonia or antheridia. It is believed that the Laminaria sporangium maturation stage could affect the gametophytes reaction to BL under laboratory culture conditions. Therefore, cryptochrome- or phototropin-like BL photoreceptors is probably involved in BL-induced development of Laminaria gametophytes.展开更多
Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica(Phaeophyceae) from heat stress were studied.Heat stress resulted in oxidative injury ...Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica(Phaeophyceae) from heat stress were studied.Heat stress resulted in oxidative injury in the kelp blades.Under heat stress significant accumulation of hydrogen peroxide(H_2O_2) and malonaldehyde(MDA),a membrane lipid peroxidation product,and a drastic decrease in chlorophyll a content were recorded.Activity of the enzymatic antioxidant system was drastically affected by heat stress.The activity of superoxide dismutase(SOD) was significantly increased while peroxidase(POD),catalase(CAT) and glutathione peroxidase(GPX) were greatly inhibited and,simultaneously,phenylalanine ammonia-lyase was activated while polyphenol oxidase(PPO) was inhibited.Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades.Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H_2O_2 and MDA content,and a lower reduction in chlorophyll a content.Pretreatment with heat acclimation and salicylic acid elevated activities of SOD,POD,CAT,GPX and PPO.Considering these results collectively,we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L.japonica,and enhanced thermotolerance may be associated,at least in part,with the elevated activity of the enzymatic antioxidant system.展开更多
Effects of fucoidan from Laminaria japonica on 2,4 dinitrochlorobenzene induced delayed type hypersensitivity (DTH) reaction and the serum levels of IgG, IgM, complement C3 and C4 were investigated in the present stud...Effects of fucoidan from Laminaria japonica on 2,4 dinitrochlorobenzene induced delayed type hypersensitivity (DTH) reaction and the serum levels of IgG, IgM, complement C3 and C4 were investigated in the present study. Results showed that oral administration of fucoidan at dose of 150 and 300 mg/(kg·d) for 9 days before the hapten challenge significantly inhibited 2,4 dinitrochlorobenzene induced delayed type hypersensitivity reaction; and also inhibited the humoral immunity. Serum C3 and C4 levels were markedly reduced by fucoidan at dose of 150 and 300 mg/kg; and serum IgG and IgM levels were reduced by fucoidan at dose of 300 mg/kg. The inhibitory effects of fucoidan on delayed type hypersensitivity suggested that it may be potential medication for chronic inflammatory diseases in the future.展开更多
The pigments in Laminaria japonica was extracted with six organic solvents and analyzed in spectroscopy analysis. The extractions conditions were screened by an orthogonal test and the quantity of extracted pigments w...The pigments in Laminaria japonica was extracted with six organic solvents and analyzed in spectroscopy analysis. The extractions conditions were screened by an orthogonal test and the quantity of extracted pigments was determined spectroscopically. The results show that: (1) among the six organic solvents, acetone was the most effective one for the extraction; (2) the optimum extraction conditions were as follows: the ratio of S/M (solvent volume/material weight) was 30 ml/g; fresh seaweed was extracted 2 times in 2h; (3) the average total content of pigments was 1.85 mg/g (calculated with dry L. japonica).展开更多
FGS was isolated and purified from laminaria japonica by enzymolysis, chromatography methods and so on. The high blood fat model was established by feeding mouse on high fat feedstuff. Compared with control group, the...FGS was isolated and purified from laminaria japonica by enzymolysis, chromatography methods and so on. The high blood fat model was established by feeding mouse on high fat feedstuff. Compared with control group, the concentration of HDL-C, the ratio of HDL-C/TC increased;while the concentration of TC, LDL-C and TG decreased in experimental groups. Conclusion: FGS was an effective serum lipid regulator and can be developed as medicine and health food.展开更多
FGS, isolated from the water solution of enzymolyzed laminaria japonica, is a mixture of acid heteroglycans. Four fractions F1, F2, F3, and F4 were obtained from FGS by ion exchange chromatography. After further purif...FGS, isolated from the water solution of enzymolyzed laminaria japonica, is a mixture of acid heteroglycans. Four fractions F1, F2, F3, and F4 were obtained from FGS by ion exchange chromatography. After further purified by gel filtration chromatography on a sepharose 2B and 6B column, we obtained F9, F10, F11, and F12. They showed single band when identified by electrophoresis. The molecular weight of F9, F10, F11, and F12 was estimated to be 216, 120, 138 and 140KD respectively. They containedа-glucosidic bond by IR and 1H-NMR analysis. The typical absorption peaks of these polysaccharides were showed in UV and IR spectra. These polysaccharides contained rha, fuc, man, gal, and uronate when identified by paper chromatography (p.c) and gas chromatography (GC). The molar ratio of these sugars was also assayed.展开更多
A genetic transformation model for the seaweed Laminaria japonica mainly includesthe following aspects:1. The method to introduce foreign genes into the kelp, L. japonicaBiolistic bombardment has been proved to be an ...A genetic transformation model for the seaweed Laminaria japonica mainly includesthe following aspects:1. The method to introduce foreign genes into the kelp, L. japonicaBiolistic bombardment has been proved to be an effective method to bombard foreign DNA throughcell walls into intact cells of both sporophytes and gametophytes. The expression of cat and lacZ was de-tected in regenerated sporophytes, which suggests that this method could induce the integration of for-eign genes. 2. Promoters to drive gene expressionThe CaMV35S promoter was first used by us to induce the expression of GUS gene in brown algae.But results of further studies suggested that CaMV35S could be a tissue-specific promoter. Our use ofSV40 promoter resulted in both transient and stable expression of lacZ and cat in sporophytes or gameto-phytes. No GUS or LacZ background was found in either sporophytes or gametophytes.3. The regeneration route of transgenic kelpThe regeneration efficiency of explants is still very low. By using female gametophytes as gene hostsand parthenogenesis as regeneration route, CAT activity and LacZ activity were detected in regeneratedsporophytes of parthenogenetic kelp.4. The way to select transgenic kelpResults of sensitivity tests showed that kelp was only sensitive to chloramphenicol and hygromycin a-mong many antibiotics. The regenerated sporophytes by parthenogenesis were more sensitive to hygromycinthan to chloramphenicol. Resistant kelp was created by transforming female gametophytes with pSV40-CAT and stimulating parthenogenesis followed by selection in medium with lethal concentration of chloram-phenicol,.5. Safety consideration of transgenic kelp1) L. japonica was originally introduced from Japan. In China it is a cultured population. The pos-sibility of its negative impact on natural populations is very low. 2) The vectors and target genes used fortransformation should be restricted In order to avoid any negative impacts on human health and environ-ment. 3)Specially devised containers (3. 6 L, made of 200 μm membrane) were used to ensure that thekelp cannot escape or be eaten by marine animals. 4) To avoid the release of spores, it is very necessaryto harvest the kelp at suitable age before the sporangium forms.展开更多
Four media (PESI solid, MS liquid, MS solid and ASP-C-I solid medium) were usedto induce callus from excised tissues of the kelp Laminaria japonica. Only PESI solid medium and MSsolid medium produced calli. Modified M...Four media (PESI solid, MS liquid, MS solid and ASP-C-I solid medium) were usedto induce callus from excised tissues of the kelp Laminaria japonica. Only PESI solid medium and MSsolid medium produced calli. Modified MS solid medium supplemented with mannitol (3%, W/V), yeastextract (0.1%, W/V), VB2(0. 5 mg/ml), VB12(0.5 mg/ml), kinetin (0. 108 μg/ml) and NAA(1.860μg/ml) showed much better effect on callus induction than non-modified MS solid medium. After24 days of induction 75 .5% of tissues in PESI solid medium showed callus formation. For modified MSsolid medium, after three months of induction 67. 3% of tissues dedifferentiated into calli. No calluscould be found after five months of induction in either MS liquid or ASP-C-I solid medium. When calliwere squashed and cultured in N-P enriched autoclaved seawater, MS liquld medium and ASP12-NTAliquid medium (both modified with kelp extract), differentiation of cells and regeneration of sporophyteswere only observed in ASP12-NTA medium supplemented with kelp extract. Gametophyte-like filamentsformed first, then eggs were released. It was suggested that sporophyte formation could be a process ofparthenogenesis. Sterilization techniques in tissue culture of L. japonica were also tested in this study.展开更多
Houttuynia cordata flavonoid and Sophora japonica L. polysaccharide were investigated to develop anti-UV sun-screening agent through UV wavelength scanning spectrum, antioxidant ability and cell viability after UVB ir...Houttuynia cordata flavonoid and Sophora japonica L. polysaccharide were investigated to develop anti-UV sun-screening agent through UV wavelength scanning spectrum, antioxidant ability and cell viability after UVB irradiation. The results showed that the extracts had strong UVA and UVB absorption ability and hydroxyl free radical scavenging ability. The S. japonica L. polysaccharide showed strong anti-UVB irradiation ability according to the cell viability experiment. It suggests that the H. cordata flavonoid and S. japonica L. polysaccharide could be combined as a candidate of anti-UV sun-screening supplement and compensate for the shortcomings of chemical sunscreens against UVA ray.展开更多
基金the financial support from the National Natural Science Foundation of China (No.21506220)
文摘In this study, molecular weight controllable degradation of algal Laminaria japonica polysaccharides(LPS) was investigated by ultrasound combined with hydrogen peroxide. Three main factors, i.e., ultrasonic power(A), ultrasonic time(B), and H_2O_2 concentration(C) were chosen for optimizing parameters by employing three-factors, three-levels BBD. The influence of degradation on structure change and antioxidant activities was also investigated. A second-order polynomial equation including molecular weight(Y) of Laminaria japonica polysaccharides and each variable parameter, i.e., ultrasonic power(A), ultrasonic time(B), and H_2O_2 concentration(C), was established: Y=20718.67-4273.13A-4000.38B-1438.75C+2333.25AB+1511.00AC+873.00BC+2838.29A^2 + 2490.79B^2+873.04C^2. The equation regression coefficient value(R^2 = 0.969) indicated that this equation was valid. The value of the adjusted determination coefficient(adjusted R^2 = 0.914) also confirmed that the model was highly significant. The results of selected experimental degradation conditions matched with the predicted value. FT-IR spectra revealed that the structures of LPS before and after degradation were not significantly changed. Antioxidant activities of LPS revealed that low Mws possessed stronger inhibitory than the original polysaccharides. The scavenging effects on superoxide radicals was the highest when IC50 of crude LPS was 4.92 mg mL^(-1) and IC50 of Mw 18.576 KDa was 1.02 mg mL^(-1), which was fourfold higher than initial polysaccharide.
文摘The parthenogenesis and natural doubling of chromosomes in wild type female gametophytes of Laminaria japonica were studied. The results indicate that not all the female gametophytes from the wild type hybrid parent can propagate through parthenogenesis. Most parthenosporophytes can mature, their spores germinate into gametophytes, the latter then developed into female sporophytes. To form these parthenosporophytes the natural doubling of chromosomes occurred mainly at the first and second cell divisions of the spores. It is thus considered that the parthenogenesis of L. japonica is inheritable and the relative genes link closely with the genes controlling the natural doubling of chromosomes and the female determination.
文摘This study on the effects of ultrasonic treatment on female gametophytes of Laminariajaponica showed that:1. Ultrasonic treatment had shortening effect on filaments of female gametophytes. Within certainperiod of time, the average length of filamentous female gametophytes was shortened.2. Ultrasonic treatment had emptying effect on cells. The number of empty cells increased with timeof treatment. Ultrasonic treatment had harmful effect on cells.3. Ultrasonic treatment could break down cell walls. The combination of frequency of 20 kHz, out-put of 15 W, 40 s and 60 s of treatment was best for this purpose. After ultrasonic treatment, the regner-ation of female gametophytes into sporophytes was effected. Female gametophytes could not recover aftertoo long period of treatment.
文摘The cultivation of the first filial generation of monoploid gametophyte clones of different Laminaria species (hybrid Laminaria) is an effective way of utilizing heterozygous vigor (heterosis). A female gametophyte clone of L. japonica and a male gametophyte clone of L. longissima were hybridized, generating Dongfang No.2 hybrid Laminaria. The parentage of this hybrid Laminaria was determined using AFLP of total DNA, SNP of the ITS region of ribosomal RNA transcription unit and microsatellite DNA variation at two loci. In addition to 167 AFLP bands shared by Dongfang No.2, L. japonica and L. longissima, Dongfang No.2 hybrid Laminaria shared another 70 and 55 bands with L. japonica and L. longissima, respectively, which were obviously more than 11 bands shared by L. japonica and L. longissima. Dongfang No.2 held both ‘T’ and ‘C’ at position 847 of the ITS region, while ‘T’ at this position was specific for L. japonica and ‘C’ for L. longissima, respectively. Dongfang No.2 also held the microsatellite DNA alleles of two parents together at two microsatellite DNA marker loci. These observations clearly proved that Dongfang No.2 is a true hybrid of L. japonica and L. longissiuma. Unfortunately, the origin of the chloroplast of Dongfang No.2 was not determined based on the variation of RuBisCo spacer. More sequence variants of both ITS region and RuBisCo spacer were identified in Dongfang No.2 and most of them did not exist in either L. japonica or L. longissima. The unexpected variants may be due to the mutation of ga- metophyte clones occurring during their vegetative amplification.
文摘Gametophytes of Laminaria japonica were cryopreserved in liquid nitrogen using encapsulation-dehydration with two-step cooling method. Gametophytes cultured at 10℃ and under continuous irradiance of 30 μmol m-2 s-1 for 3 weeks were en- capsulated in calcium alginate beads. The beads were dehydrated in 0.4 molL-1 sucrose prepared with seawater for 6 h, desiccated in an incubator set at 10℃ and 70% relative humidity for 4 h, pre-frozen at either ?40℃ or ?60℃ for 30 min, and stored in liquid nitrogen for >24 h. As high as 43% of survival rate was observed when gametophytes were thawed by placing the beads in 40℃ seawater and re-hydrated in 0.05 molL-1 citrate sodium prepared using 30‰ NaCl 7 d later. More cells of male gametophytes sur- vived the whole procedure in comparison with female gametophytes. The cells of gametophytes surviving the preservation were able to grow asexually and produce morphologically normal sporophytes.
基金The Hi-Tech Research and Development Program (863) of China (Youth Program) (No. 2004AA639770) and the Chinese NationalBasic Research Priorities Program (No. G1999012004)
文摘We collected the diseased blades of Laminaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as Alteromon as espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and to find the possibly effective mechanism. Results showed that: (1) The blades of L. japonica exhibited symptoms of lesion, bleaching and deterioration when infe cted by the bacterium, and their growth and photosynthesis were dramatically sup pressed. At the same time, the reactive oxygen species(ROS) generation enhanced obviously, and the relative membrane permeability increased significantly. The c ontents of malonaldehyde(MDA) and free fatty acid in the microsomol membrane gre atly elevated, but the phospholipid content decreased. Result suggested an obvio us peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. (2) The simultaneous assay on the antioxidant enzyme activiti es demonstrated that superoxide dismutase (SOD) and catalase(CAT) increased grea tly when infected by the bacterium, but glutathione peroxidase(Gpx) and ascorbat e peroxidase(APX) did not exhibit active responses to the bacterium throughout t he experiment. (3) The histomorphological observations gave a distinctive eviden ce of the severity of the lesions as well as the relative abundance in the bacte rial population on the blades after infection. The bacterium firstly invaded int o the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L. japonica.
基金The National Natural Science Foundation of China under grant Nos 39800105 and 30471328the Shanghai Development Foundation of Education under grant No. 98-SG-32Key Discipline of Shanghai Municipal Education Commission (J50701)
文摘For the population genetics analysis of the naturally grown brown seaweed Laminaria japonica (Laminariales,Phaeophyta) sampled from Dalian,Yantai,Weihai,Rongcheng and Qingdao in China,ten primers were employed to produce 88 bands as revealed by randomly amplified polymorphic DNA (RAPD) markers,and all these bands were polymorphic.According to these band patterns,there were 94 distinct phenotypes occurred in 100 samples indicating the high heterozygosity of this kelp.Dalian population samples showed the highest percentage of polymorphism (71.67%),and also the higher diversity estimated on the basis of the Shannon’s index (8.498),suggesting that this population could be chosen as the best resource for genetic breeding.The highest diversity of Yantai population possibly resulted from the introduction of L.longissima used for interspecific cross breeding with L.japonica cultivated in China.From Dalian southwards to Qingdao,the genetic variation of the five populations became less with a decrease in latitude,possibly due to the natural selection especially of high temperature.The genetic distance (Φ ST values) of the five populations was a little significantly correlated with the geographical distance (r=0.496) at P =0.05 by Mantel’s test.Weihai,Rongcheng and Yantai populations were closely grouped genetically together by Neighbor-joining cluster analysis probably in that the dispersal of the kelp by propagules more easily occurring in the range of relatively short distance.The analysis of molecular variance (AMOVA) also demonstrated that the relatively higher variation occurred among populations (71.49%) at an extremely significant level (P <0.000 1).All these evidence showed that there was a relatively distinct genetic differentiation among the sampled kelp populations,and L.japonica grown in China was also rather heterozygous in heredity.
基金This research was supported by the NSFC (No.40376049) and Japan Society for the Promotion of Science (The Invitation Fellowship for Research in Japan 2002)
文摘Laminaria gametophyte was greatly influenced by light in its growth and development. Using light-emitting diodes (LED) as blue and red light sources, we analyzed the light effect on gametophytes devel- opment of Laminaria japonica Aresch. The gametophytes were obtained from zoospores collected in April, May, July, 2003 and September, 2004. We found that the growth of gametophytes was stimulated by increasing inten- sity of blue light (BL) and red light (RL) illumination, of which BL was obviously stronger than that of RL. The fertilization of gametophytes depended largely on BL, and only sufficient BL illumination could take the repro- ductive effect. In addition, we noticed that there was a significant difference in light responses for gametophytes developed from zoospore collected in different times. For zoospores released in April, under BL1 (73.90 μmol photons/m·s), the unicellular female gametophytes and multi-cellular male gametophytes produced eggs and sperms respectively, and further developed towards sporophytes. However, for gametophytes developed in May, July or September, they became multi-cellular and never formed oogonia or antheridia. It is believed that the Laminaria sporangium maturation stage could affect the gametophytes reaction to BL under laboratory culture conditions. Therefore, cryptochrome- or phototropin-like BL photoreceptors is probably involved in BL-induced development of Laminaria gametophytes.
基金Supported by the Open Funds of the Key Oceanic Science and Engineering Laboratory of National Bureau of Oceanography(MESE-2008-01)the Specialized Research Program for Marine Public Welfare Industry,SOA(No.200805066)
文摘Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica(Phaeophyceae) from heat stress were studied.Heat stress resulted in oxidative injury in the kelp blades.Under heat stress significant accumulation of hydrogen peroxide(H_2O_2) and malonaldehyde(MDA),a membrane lipid peroxidation product,and a drastic decrease in chlorophyll a content were recorded.Activity of the enzymatic antioxidant system was drastically affected by heat stress.The activity of superoxide dismutase(SOD) was significantly increased while peroxidase(POD),catalase(CAT) and glutathione peroxidase(GPX) were greatly inhibited and,simultaneously,phenylalanine ammonia-lyase was activated while polyphenol oxidase(PPO) was inhibited.Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades.Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H_2O_2 and MDA content,and a lower reduction in chlorophyll a content.Pretreatment with heat acclimation and salicylic acid elevated activities of SOD,POD,CAT,GPX and PPO.Considering these results collectively,we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L.japonica,and enhanced thermotolerance may be associated,at least in part,with the elevated activity of the enzymatic antioxidant system.
文摘Effects of fucoidan from Laminaria japonica on 2,4 dinitrochlorobenzene induced delayed type hypersensitivity (DTH) reaction and the serum levels of IgG, IgM, complement C3 and C4 were investigated in the present study. Results showed that oral administration of fucoidan at dose of 150 and 300 mg/(kg·d) for 9 days before the hapten challenge significantly inhibited 2,4 dinitrochlorobenzene induced delayed type hypersensitivity reaction; and also inhibited the humoral immunity. Serum C3 and C4 levels were markedly reduced by fucoidan at dose of 150 and 300 mg/kg; and serum IgG and IgM levels were reduced by fucoidan at dose of 300 mg/kg. The inhibitory effects of fucoidan on delayed type hypersensitivity suggested that it may be potential medication for chronic inflammatory diseases in the future.
基金the Technical Program of Jiangsu Province (BE 2006383)the Talent Program of Chinese Academy of Sciences (Dongbei Zhi Chun)
文摘The pigments in Laminaria japonica was extracted with six organic solvents and analyzed in spectroscopy analysis. The extractions conditions were screened by an orthogonal test and the quantity of extracted pigments was determined spectroscopically. The results show that: (1) among the six organic solvents, acetone was the most effective one for the extraction; (2) the optimum extraction conditions were as follows: the ratio of S/M (solvent volume/material weight) was 30 ml/g; fresh seaweed was extracted 2 times in 2h; (3) the average total content of pigments was 1.85 mg/g (calculated with dry L. japonica).
文摘FGS was isolated and purified from laminaria japonica by enzymolysis, chromatography methods and so on. The high blood fat model was established by feeding mouse on high fat feedstuff. Compared with control group, the concentration of HDL-C, the ratio of HDL-C/TC increased;while the concentration of TC, LDL-C and TG decreased in experimental groups. Conclusion: FGS was an effective serum lipid regulator and can be developed as medicine and health food.
文摘FGS, isolated from the water solution of enzymolyzed laminaria japonica, is a mixture of acid heteroglycans. Four fractions F1, F2, F3, and F4 were obtained from FGS by ion exchange chromatography. After further purified by gel filtration chromatography on a sepharose 2B and 6B column, we obtained F9, F10, F11, and F12. They showed single band when identified by electrophoresis. The molecular weight of F9, F10, F11, and F12 was estimated to be 216, 120, 138 and 140KD respectively. They containedа-glucosidic bond by IR and 1H-NMR analysis. The typical absorption peaks of these polysaccharides were showed in UV and IR spectra. These polysaccharides contained rha, fuc, man, gal, and uronate when identified by paper chromatography (p.c) and gas chromatography (GC). The molar ratio of these sugars was also assayed.
文摘A genetic transformation model for the seaweed Laminaria japonica mainly includesthe following aspects:1. The method to introduce foreign genes into the kelp, L. japonicaBiolistic bombardment has been proved to be an effective method to bombard foreign DNA throughcell walls into intact cells of both sporophytes and gametophytes. The expression of cat and lacZ was de-tected in regenerated sporophytes, which suggests that this method could induce the integration of for-eign genes. 2. Promoters to drive gene expressionThe CaMV35S promoter was first used by us to induce the expression of GUS gene in brown algae.But results of further studies suggested that CaMV35S could be a tissue-specific promoter. Our use ofSV40 promoter resulted in both transient and stable expression of lacZ and cat in sporophytes or gameto-phytes. No GUS or LacZ background was found in either sporophytes or gametophytes.3. The regeneration route of transgenic kelpThe regeneration efficiency of explants is still very low. By using female gametophytes as gene hostsand parthenogenesis as regeneration route, CAT activity and LacZ activity were detected in regeneratedsporophytes of parthenogenetic kelp.4. The way to select transgenic kelpResults of sensitivity tests showed that kelp was only sensitive to chloramphenicol and hygromycin a-mong many antibiotics. The regenerated sporophytes by parthenogenesis were more sensitive to hygromycinthan to chloramphenicol. Resistant kelp was created by transforming female gametophytes with pSV40-CAT and stimulating parthenogenesis followed by selection in medium with lethal concentration of chloram-phenicol,.5. Safety consideration of transgenic kelp1) L. japonica was originally introduced from Japan. In China it is a cultured population. The pos-sibility of its negative impact on natural populations is very low. 2) The vectors and target genes used fortransformation should be restricted In order to avoid any negative impacts on human health and environ-ment. 3)Specially devised containers (3. 6 L, made of 200 μm membrane) were used to ensure that thekelp cannot escape or be eaten by marine animals. 4) To avoid the release of spores, it is very necessaryto harvest the kelp at suitable age before the sporangium forms.
文摘Four media (PESI solid, MS liquid, MS solid and ASP-C-I solid medium) were usedto induce callus from excised tissues of the kelp Laminaria japonica. Only PESI solid medium and MSsolid medium produced calli. Modified MS solid medium supplemented with mannitol (3%, W/V), yeastextract (0.1%, W/V), VB2(0. 5 mg/ml), VB12(0.5 mg/ml), kinetin (0. 108 μg/ml) and NAA(1.860μg/ml) showed much better effect on callus induction than non-modified MS solid medium. After24 days of induction 75 .5% of tissues in PESI solid medium showed callus formation. For modified MSsolid medium, after three months of induction 67. 3% of tissues dedifferentiated into calli. No calluscould be found after five months of induction in either MS liquid or ASP-C-I solid medium. When calliwere squashed and cultured in N-P enriched autoclaved seawater, MS liquld medium and ASP12-NTAliquid medium (both modified with kelp extract), differentiation of cells and regeneration of sporophyteswere only observed in ASP12-NTA medium supplemented with kelp extract. Gametophyte-like filamentsformed first, then eggs were released. It was suggested that sporophyte formation could be a process ofparthenogenesis. Sterilization techniques in tissue culture of L. japonica were also tested in this study.
基金Supported by College Students'Practice Innovation Training Project in Henan Province(No.201711834006)Henan Provincial Department of Education(No.15A350008)
文摘Houttuynia cordata flavonoid and Sophora japonica L. polysaccharide were investigated to develop anti-UV sun-screening agent through UV wavelength scanning spectrum, antioxidant ability and cell viability after UVB irradiation. The results showed that the extracts had strong UVA and UVB absorption ability and hydroxyl free radical scavenging ability. The S. japonica L. polysaccharide showed strong anti-UVB irradiation ability according to the cell viability experiment. It suggests that the H. cordata flavonoid and S. japonica L. polysaccharide could be combined as a candidate of anti-UV sun-screening supplement and compensate for the shortcomings of chemical sunscreens against UVA ray.
