共查询到20条相似文献，搜索用时 62 毫秒
1.
To establish a micropropagation system of three Laurencia complex species (Laurencia okamurai, Laurencia tristicha, and Chondrophycus undulatus) by tissue culture techniques, we studied the regeneration characteristics and optimal culture conditions of axenic algal
fragments cultured on solid medium and in liquid medium. Regeneration structures were observed and counted regularly under
a reverse microscope to investigate the regeneration process, polarity and optimal illumination, and temperature and salinity
levels. The results show that in most cultures of the three species, we obtained bud regeneration on solidified medium with
0.5% agar and in liquid medium. Rhizoid-like regeneration was filamentous and developed from the lower cut surface of fragments
in L. okamurai, but was discoid and developed from the apical back side of bud regeneration in L. tristicha and C. undulatus. Regeneration polarity was localized to the apical part of algal fronds in all three species, and on fragments cut from the
basal part of algae buds could develop from both the upper and the lower cut surfaces. Buds could develop from both the medullary
and the cortical portions in L. okamurai and C. undulatus, while in L. tristicha, buds only emerged from the cortex. The optimal culture conditions for L. okamurai were 4 500 lx, 20°C and 35 (salinity); for C. undulatus, 4 500 lx, 20°C and 30; and for L. tristicha, 4 500 lx, 25°C and 30. 相似文献
2.
STUDIES ON CULTURE CONDITIONS OF BENTHIC DIATOMS FOR FEEDING ABALONE I.EFFECTS OF TEMPERATURE AND LIGHT INTENSITY ON GROWTH RATE 总被引：2，自引：0，他引：2
INTRODUCTIONBenthicdiatomscomPrisethemaininitialfoodforjuvenileabalone.ItisimPortanttocIJlturehighqualitybenthicdiatornsduringtheeariystageofjuvenileabaloneculture.AtpresentthespeCesofbenthicdiatomsusedinabalonebedingfannsprirnarilycomefromnaturalpopulations.SomespedesinseveralgenerasuchasNavicula,Ntzchia,Caroneis,Achnanthes,AmPhoraareusuallythedothenantspch(Chen,etal.,l977,Ukiandaxuchi,l979,Nonnan-Boudnauetal.,l986,Austinetal.l990).Inordertoselodsornespedeswithhighadaptability,fas… 相似文献
3.
We evaluated the effect of water temperature on the growth and physiology of the Chinese longsnout catfish (Leiocassis longirostris Günther). The fish were reared at four temperatures (20, 25, 30, and 35°C) and sampled on days 7, 20, and 30. We measured plasma levels of insulin, free thyroxine (FT4), free 3,5,3′-triiodothyronine (FT3), lysozyme and leukocyte phagocytic activity. The optimum water temperature for growth was 27.7°C. The plasma levels of insulin and FT4 declined significantly (P<0.05) on day 30 at temperatures above 20°C. Lysozyme activity was significantly (P<0.05) lower at 25°C than at other temperatures. We conclude that final weight, insulin, FT4, and lysozyme were significantly affected by water temperature. 相似文献
4.
The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms (HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that
the B. plicatilis obtained sufficient nutrition from Prorocentrum donghaiense to support net population increase. With exposure to 2.5×104 cells mL−1 of P. donghaiense, the number of B. plicatilis increased faster than it did when exposed to other four algal densities (5, 10, 15 and 20 ×104 cells mL−1), and the increase rate of B. plicatilis population (r) at this algal density was 0.104 ± 0.015 rd−1. Cell densities of P. donghaiense decreased due to the grazing of B. plicatilis. In contrast, Heterosigma akashiwo had an adverse effect on B. plicatilis population and its growth was largely unaffected by rotifer grazing. In this case, B. plicatilis population decreased and H. akashiwo grew at a rate similar to that of the control. 相似文献
5.
Competition among HAB (Harmful Algal Bloom) species Dinoflagellate Alexandrium tamarense, Raphidophyte Heterosigma carterae, and Diatom Skeletonema costatum was studied in the laboratory. Experiments with these three major HAB species under combinations of different salinities (10, 18, 25, 30, 35) and temperatures (19℃, 25℃) were carried out. The results showed that S. costatum successfully competed with the other two species at salinities of 18, 25,30, and 35 at temperatures of 19℃ and 25℃. However, H. carterae showed its advantage at low salinity of 10 and became the single dominant species at salinity 10 and 25℃. A. tamarense could not compete successfully with the other two species especially at low salinities. However, it could remain at low density in the presence of higher densities of other algae. 相似文献
6.
Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr(VI),Cr(III),Pb(II) and Cd(II) by algal biomass obtained from algae Sargassum wightii(brown) and Caulerpa racemosa(green).Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr(VI),Cr(III),Pb(II) and Cd(II) ions.C.racemosa exhibited 85% biosorption of Cd(II) and Cr(VI),and 50% biosorption of Cr(III) and Pb(II).The results of our study suggest that seaweed biomass can be used efficiently for 相似文献
7.
Estivation, hibernation, and starvation are indispensable inactive states of sea cucumbers Apostichopus japonicus in nature and in culture ponds. Generally, temperature is the principal factor that induces estivation or hibernation in
the sea cucumber. The present study provided insight into the physiological adaptations of A. japonicus during the three types of inactivity (hibernation, estivation, and starvation) by measuring the oxygen consumption rates
(Vo2) and biochemical compositions under laboratory conditions of low (3°C), normal (17°C) and high (24°C) temperature. The results
show that the characteristics of A. japonicus in dormancy (hibernation and estivation) states were quite different from higher animals, such as fishes, amphibians, reptiles,
and mammals, but more closely resembled a semi-dormant state. It was observed that the shift in the A. japonicus physiological state from normal to dormancy was a chronic rather than acute process, indicated by the gradual depression
of metabolic rate. While metabolic rates declined 44.9% for the estivation group and 71.7% for the hibernation group, relative
to initial rates, during the 36 d culture period, metabolic rates were not maintained at constant levels during these states.
The metabolic depression processes for sea cucumbers in hibernation and estivation appeared to be a passive and an active
metabolic suppression, respectively. In contrast, the metabolic rates (128.90±11.70 μg/g h) of estivating sea cucumbers were
notably higher (107.85±6.31 μg/g h) than in starving sea cucumbers at 17°C, which indicated that the dormancy mechanism here,
as a physiological inhibition, was not as efficient as in higher animals. Finally, the principle metabolic substrate or energy
source of sea cucumbers in hibernation was lipid, whereas in estivation they mainly consumed protein in the early times and
both protein and lipid thereafter. 相似文献
8.
Growth and energy budget of the polychaete, Neanthes japonica, at various temperatures (17, 20, 23, 26 and 29°) were investigated in this study. The growth, as indicated by final dry
weight and specific growth rate (SGR), increased with increasing temperature, with the maximum level at 26°C, and then decreased significantly at 29°C. A similar
trend was observed in feeding rate, food conversion efficiency (FCE) and apparent digestive rate (ADR). However, no significant differences were detected in ADR among all the temperature treatments. In the pattern of energy allocation, faeces energy was only a small component of energy
budget and had little influence on the proportion of food energy allocated to growth. The metabolic energy accounted for a
large portion of energy intake for each temperature treatment. The nitrogen excretion was appreciable with changing temperature.
The two expenditure terms (respiration energy and excretion energy) in energy budget were the major factors influencing the
proportion of food energy allocated to growth. These results revealed that temperature affected the growth of N. japonica mainly by influencing feeding rate and FCE. In addition, regression equations describing the relationship between feeding rate, faecal production, SGR, FCE and temperature were obtained. The optimum temperatures for feeding rate, FCE and SGR were estimated at 25.01°C, 24.24°C and 24.73°C, respectively, from the regression equations. 相似文献
9.
10.
In this study,effects of elevated air temperatures on thermal and hydrologic process of the shallow soil in the active layer were investigated. Open-top chambers(OTCs)were utilized to increase air temperatures 1-2℃ in OTC-1 and 3-5℃ in OTC-2 in the alpine meadow ecosystem on the Qinghai- Tibetan Plateau.Results show that the annual air temperatures under OTC-1 and OTC-2 were 1.21℃ and 3.62℃ higher than the Control,respectively.The entirely-frozen period of shallow soil in the active layer was shortened and the fully thawed period was prolonged with temperature increase.The maximum penetration depth and duration of the negative isotherm during the entirely-frozen period decreased, and soil freezing was retarded in the local scope of the soil profile when temperature increased.Meanwhile, the positive isotherm during the fully-thawed period increased,and the soil thawing was accelerated.Soil moisture under different manipulations decreased with the temperature increase at the same depth. During the early freezing period and the early fully- thawed period,the maximum soil moisture under the Control manipulation was at 0.2 m deep,whereas under OTC-1 and OTC-2 manipulations,the maximum soil moisture were at 0.4-0.5 m deep. These results indicate that elevated temperatures led to a decrease of the moisture in the surface soil.The coupled relationship between soil temperature and moisture was significantly affected by the temperature increase.During the freezing and thawing processes, the soil temperature and moisture under different manipulations fit the regression model given by the equationθV=a/{1+exp[b(TS+c)]}+d. 相似文献
11.
Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and identified. The bacteria fermentation broth could exert inhibitory effects on the growth of Skeletonema costatum and barnacle larvae. A procedure was employed to extract and identify the antifouling compounds. Firstly, a toxicity test was conducted by graduated pH and liquid-liquid extraction to determine the optimal extraction conditions. The best extraction conditions were found to be pH 2 and 100% petroleum ether. The EC50 value of the crude extract of K. sedentarius against the test microalgae was 236.7 ± 14.08 μg mL-1, and that of B. cereus was 290.6 ± 27.11 μg mL-1. Secondly, HLB SPE columns were used to purify the two crude extracts. After purification, the antifouling activities of the two extracts significantly increased: the EC50 of the K. sedentarius extract against the test microalgae was 86.4 ± 3.71 μg mL-1, and that of B. cereus was 92.6 ± 1.47 μg mL-1. These results suggest that the metabolites produced by the two bacterial strains are with high antifouling activities and they should be fatty acid compounds. Lastly, GC-MS was used for the structural elucidation of the compounds. The results show that the antifouling compounds produced by the two bacterial strains are myristic, palmitic and octadecanoic acids. 相似文献
12.
This Mar. 1993 to Aug. 1994 study on suspended conchocelis ofPorphyra haitanensis showed that there were three patterns for development of vegetative filaments: filaments to filaments by “budding”; filaments
to sporangial branchlets by “budding”, or cell swelling. There were also three patterms for sporangial branchlet development:
vegetatively propagating, changing into conchospores, or dying. Each developmental stage had one or more different developmental
directions between vegetative filaments and sporangial branchlets. Developments from conchosporangial branchlets to conchospores
were sequential and irreversible. Although sporangial branchlets formed at 29°C could give rise to filaments, they could not
propagate as healthily under the same conditions as those formed at 25°C did. Probably the crucial period of plant cell differentiation
is in the late stage of sporangial branchlets. In line with the developmental directions of different stages, the authors
regulated the development of conchocelis to get ideal different developmental stages materials to obtain very developmentally
homogeneous stages, including filaments and sporangial branchlets.
Contribution No 3283 from the Institute of Oceanology, Chinese Academy of Sciences.
Study supported by the Climbing Project B PD-B6-4-2 of the State Science and Technology Commission of China. 相似文献
13.
Jian-guo Liu Hall David O. Rao Krishna K. Tsygankov Anatoly A. Sveshnikov Dmitry A. 《中国海洋湖沼学报》1998,16(1):118-126
H2 photoproduction and nitrogenase activities in two strains ofAnabaena variabilis marked wild type ATCC 29413 and mutant PK84 exposed to thermal stress (temperature higher than the normal incubation temperature of 30°C) were studied. Cultures of both strains collected from any interval of logarithmic growth phase exhibited high H2 photoproduction and nitrogenase activities when exposed to limited time heat shock during the assay process. In contrast, the algal H2 photoproduction rate of both strains fluctuated with long term thermal stress caused by increasing the growth temperature from 30°C to 36°C.
The changes of nitrogenase (the key H2 photobiosynthetic enzyme) activities in the mutant PK84 showed variation tendency similar to that of H2 photoproduction during exposure to thermal stress, indicating that fluctuation of H2 photoproduction in the mutant was mainly due to the variation of nitrogenase activities. A temporary maximal H2 photoproduction in the mutant PK84 (wild type ATCC29413) was observed when cells grew at 36°C for 14 (6) days. However, the responses of nitrogenase activities in the wild type to thermal stress were not completely similar to those in the mutant in spite of similar variations of H2 photoproduction in both strains. The data obtained in these studies suggested that the activities of other enzymes (in the wild strain) involved in H2 photoproduction were affected by thermal stress since H2 photoproduction maximized or dropped to 0 without variation tendency similar to that of nitrogenase activities.
Furthermore, an enhancement of H2 photoproduction speed of the mutant strain cultured in a 4.4 L laboratory photobioreactor was also observed when it was subjected to short time continuous charge of argon, and temperature rise.
All these results indicated that high temperature plays an important role in the photo-autotrophic H2 photoproduction, and that long term thermal stress is unfavourable for net H2 photoproduction in both strains ofA. variabilis though short-time heat shock is conducive to H2 photoproduction.
相似文献14.
Effect of temperature and irradiance on growth and reproduction of Enteromorpha prolifera that bloomed offshore along the Qingdao coast in summer 2008, was studied. It was showed that E. prolifera propagated mainly asexually with specific growth rate （SGR） of 10.47 at 25℃/40 μmol m^-2s^-1. Under this condition, gametes with two flagellate formed and released in 5 days. At the beginning of the development, the unicell gamete divided into two cells with heteropolarity, and then the apical cell developed into thalli primordial cells, whereas the basal cell developed into rhizoid primordial cells. In 8-day culture, the monoplast gamete developed into juvenile germling of 240 μm in length. Unreleased gametes can develop directly within the alga body. E. prolifera could either reproduce through lateral branching or fragmenting except apomixis revealed by Microscopic observation. On aged tissue of E. prolifera, although the degraded pigments partially remained in faded algal filaments, numerous vegetative cells could still divide actively in the algal tissues. 相似文献
15.
PEI Haiyan ) and HU Wenrong ) ) * ) College of Environmental Science Engineering Ocean University of China Qingdao P.R.China ) Shandong Provincial Engineering Centre on Environmental Science Technology Jinan P.R.China ) School of Environmental Science Engineering Shandong University Jinan P.R.China 《中国海洋大学学报(英文版)》2006,5(4):368-374
Lytic Characteristics and Identification of Two Alga-lysing Bacterial StrainsBeaulieu, S. E., M. R. Sengco, and D. M. Anderson, 2005. Using clay to control harmful algal blooms: deposition and resuspension of clay/algal flocs. Harmful Algae . (4): 123-138… 相似文献
16.
The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopus japonicus, including relative gut mass (RGM), amylase, lipase, pepsin and trypsin activities were studied at temperatures of 7, 14,
21, and 28°C over a period of 40 days. Results show that RGM significantly decreased after 40 days at 21°C and markedly decreased
over the whole experiment period at 28°C; however, no significant effect of duration was observed at 7 or 14°C. At 14°C, trypsin
activity significantly decreased over 10 and 20 days, then increased; amylase and trypsin activity significantly decreased
after 40 days at 28°C. However, no significant effect of duration was found on amylase, pepsin or trypsin activities in the
other temperature treatment groups. At 28°C, lipase activity peaked in 20 days and then markedly decreased to a minimum at
the end of the experiment. On the other hand, pepsin activity at 28°C continuously increased over the whole experimental period.
Principle component analysis showed that sea cucumbers on day 40 in the 21°C group and in the previous 20 days in the 28°C
group were in the prophase of aestivation. At 28°C, sea cucumbers aestivated at 30–40 days after the start of the experiment.
It is concluded that the effect of temperature on the digestion of A. japonicus is comparatively weak within a specific range of water temperatures and aestivation behavior is accompanied by significant
changes in RGM and digestive enzyme activities. 相似文献
17.
Effects of temperatures and salinities on oxygen consumption and ammonia-N excretion rate of clamMeretrix meretrix were studied in laboratory from Oct. 2003 to Jan. 2004. Two schemes were designed in incremented temperature at 10, 15, 20,
25°C at 31.5 salinity and in incremented salinity at 16.0, 21.0, 26.0, 31.5, 36.0, and 41.0 at 20°C, all for 8–10 days. From
10 to 25°C, both respiration and excretion rate were increased. One-way ANOVA analysis demonstrated significant difference
(P<0.01) in physiological parameters in this temperature range except between 15 and 20°C. The highestQ
10 thermal coefficient value (12.27) was acquired between 10 and 15°C, and about 1 between 15 and 20°C, indicatingM. meretrix could well acclimate to temperature changes in this range. Salinity also had significant effects on respiration and excretion
rate (P<0.05). The highest values of respiration and excretion rate ofM. meretrix were recorded at 16.0 salinity (20°C). These two physiological parameters decreased as salinity increased until reached the
minimumQ
10 value at 31.5 (20°C), then again, these parameters increased with increasing salinity from 31.5 to 41.0.M. meretrix can catabolize body protein to cope with osmotic pressure stress when environmental salinity is away from its optimal range.
No significant difference was observed between 26.0 and 36.0 in salinity (P>0.05), suggesting that a best metabolic salinity range for this species is between 26.0 and 36.0.
This work is supported by National High-Tech R & D Program of China. (863 Program) (2002AA603014). 相似文献
18.
To improve the expression efficiency of exogenous genes in Chlamydomonas reinhardtii, a high efficient expression vector was constructed. Green fluorescent protein （GFP） was expressed in C. reinhardtii under the control of promoters： RBCS2 and HSP70A-RBCS2. Efficiency of transformation and expression were compared between two transgenic algae： RBCS2 mediated strain Tran-Ⅰ and HSP70A-RBCS2 mediated strain Tran-Ⅱ. Results show that HSP70A-RBCS2 could improve greatly the transformation efficiency by approximately eightfold of RBCS2, and the expression efficiency of GFP in Tran-Ⅱ was at least double of that in Tran-Ⅰ. In addition, a threefold increase of GFP in Tran-Ⅱ was induced by heat shock at 40℃. All of the results demonstrated that HSP70A-RBCS2 was more efficient than RBCS2 in expressing exogenous gene in C. reinhardtii. 相似文献
19.
ImooUrnONTheedycarsePiddricofprawndiscaseintheprawnculturecoastalarmsofChi-naandsoutheastAsiaresultedinnoproduCtinnoutputfromrnostprawnpondsandheaVyerenoAnclosscyumbull,l994).Upt0now,devemeasimtopreventandtreatthediseasehavenotbopresental,althoughwaterenvironmentdeteriorationisconunn-lyknowntobethekcyfactorcausingthisdhase(Jiang,l994).ThispreliIninrystudyonthereati0nsbetweenprawndiseaseandfactorsthatseriouslyaffodwatetenvirDimtalquality(WaterteInPeratllre,waterexchangeamount,andarnountSa… 相似文献
20.
Thirty-three species of marine algae belonging to Rhodophyta, Phaeophyta and Chlorophyta from the Fujian coast were examined for agglutinins with different animal and human erythrocytes. Protein extracts from 26 species were active against at least one type of the erythrocytes tested. There were 3 species (Grateloupia imbricata, lshigefoliacea and Entermorpha prolifera) whose extracts could agglutinate all the erythrocytes used. The lowest protein concentration required to produce erythrocyte agglutination varied remarkably, from 3.1μg/ml to 500μg/ml . The strongest activity was found in the agglutina-tion of rabbit erythrocytes by Gloiopeltis furcata extract. Inhibition assays performed with nine mono- and bisaccharides indicated that agglutinations of rabbit erythrocytes by extracts of 7 species were inhibited by one or more types of the sugars assayed. The agglutinating activity shown by extracts of most species wasnot affected when the test solution was heated to 90℃, but was lost at 95℃ - 100℃. A few extracts losttheir activity at 60 RS, 65 RS and 75 RS, respectively. 相似文献