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51.
For the first time somatic spotlike formations of 1.5 mm in diameter and height up to 0.5 mm were revealed in thalli of the red alga Palmaria palmata reared in an aerated stirred culture. It was determined that some cortical cells of the thallus are able to divide in the periclinal and anticlinal directions forming spots. Deep freezing and subsequent thawing of thalli showed that the cortical cells of spots were meristematic cells. In certain conditions they enabled the formation of prolifications, which germinated plantlets. These clusters of meristem tissue in the cortical layer of cells of the thallus of P. palmata, which were formed in the culture as in nature, function as growth cells facilitating growth of thalli in thick and natural “planting material” formed upon thalli fragmenting after their freezing in the winter season. 相似文献
52.
Morsy FM Nakajima M Yoshida T Fujiwara T Sakamoto T Wada K 《Photosynthesis research》2008,95(1):73-85
Ferredoxin-NADP+ oxidoreductase (FNR) catalyzing the terminal step of the linear photosynthetic electron transport was purified from the cyanobacterium
Spirulina platensis and the red alga Cyanidium caldarium. FNR of Spirulina consisted of three domains (CpcD-like domain, FAD-binding domain, and NADP+-binding domain) with a molecular mass of 46 kDa and was localized in either phycobilisomes or thylakoid membranes. The membrane-bound
FNR with 46 kDa was solublized by NaCl and the solublized FNR had an apparent molecular mass of 90 kDa. FNR of Cyanidium consisted of two domains (FAD-binding domain and NADP+-binding domain) with a molecular mass of 33 kDa. In Cyanidium, FNR was found on thylakoid membranes, but there was no FNR on phycobilisomes. The membrane-bound FNR of Cyanidium was not solublized by NaCl, suggesting the enzyme is tightly bound in the membrane. Although both cyanobacteria and red algae
are photoautotrophic organisms bearing phycobilisomes as light harvesting complexes, FNR localization and membrane-binding
characteristics were different. These results suggest that FNR binding to phycobilisomes is not characteristic for all phycobilisome
retaining oxygenic photosynthetic organisms, and that the rhodoplast of red algae had possibly originated from a cyanobacterium
ancestor, whose FNR lacked the CpcD-like domain. 相似文献
53.
Local and chemical distribution of phlorotannins in brown algae 总被引:4,自引:2,他引:2
Toshiyuki Shibata Shigeo Kawaguchi Yoichiro Hama Masanori Inagaki Kuniko Yamaguchi Takashi Nakamura 《Journal of applied phycology》2004,16(4):291-296
The local and chemical distribution of phlorotannins among the Japanese Laminariaceae, Eisenia bicyclis, Ecklonia cava and Ecklonia kurome, was investigated. As a result of light microscopy observations with vanillin-HCl staining, phlorotannins were found to be accumulated within the vegetative cells of the outer cortical layer of the thalli, regardless of the species, stage of growth or organ. Crude phlorotannins comprised about 3.0% of the algal powder for each of the algae. High-performance liquid chromatography (HPLC) showed that the phlorotannins of E. bicyclis were composed of phloroglucinol (0.9%), phloroglucinol tetramer (4.4%), eckol (7.5%), phlorofucofuroeckol A (21.9%), dieckol (23.4%), and 8,8'-bieckol (24.6%), plus some other unknown phenolic compounds (17.3%). The composition of the phlorotannins differed little among the Laminariaceae, except for a significantly larger amount of the tetramer, MW 478, in E. bicyclis. 相似文献
54.
Jonathan C. Hagopian Pi Nyvall Mariana C. de Oliveira 《Plant Molecular Biology Reporter》2002,20(4):399-406
We report a straightforward protocol for isolating plastid DNA from an enriched rhodoplast fraction of the red algaGracilaria tenuistipitata. Plastids were purified using differential centrifugation and 2-step sucrose density gradients. We found that 10% polyethylene
glycol 4000 was essential for maintaining plastid integrity prior to lysis. Plastid DNA isolated directly from the purified
rhodoplasts was sufficiently pure for restriction endonuclease fragment analyses. Database comparisons of sequences generated
randomly from a shotgun genomic library indicated that plastid DNA was 89% pure following ultracentrifugation in isopycnic
cesium chloride equilibrium gradients. The protocol yields 30–50 μg of plastid DNA per 100 g of fresh algal tissue. 相似文献
55.
Food quality for Eudiaptomus gracilis: the importance of particular highly unsaturated fatty acids 总被引:1,自引:1,他引:0
1. Development times and survival of nauplii and copepodites of the freshwater calanoid Eudiaptomus gracilis were measured on comparably sized Cryptomonas sp. and two strains of Chlamydomonas reinhardii under food saturated conditions (1 mg C L−1) to investigate the nutritional quality of these algae.
2. Cryptomonas sp. supported complete ontogenesis of nauplii to adults, whereas both strains of C. reinhardii were inadequate for the development of nauplii and copepodites and resulted in high mortality. The nutritional deficiency of both strains of C. reinhardii was compensated for by Cryptomonas sp. when the latter constituted ≥50% of dietary carbon. Pulses of Cryptomonas sp. had a similar compensatory effect.
3. In comparison to Cryptomonas sp., both strains of C. reinhardii were deficient in the three highly unsaturated fatty acids (HUFAs) stearidonic, eicosapentaenoic and docosahexaenoic acid. We manipulated the fatty acid content of C. reinhardii by externally adding these three HUFAs to the alga so that the fatty acid profile resembled that of Cryptomonas sp. This supplementation did not improve food quality, however, indicating that the nutritional deficiency of both strains of C. reinhardii for the ontogenesis of E. gracilis is not due to a lack of these three HUFAs. 相似文献
2. Cryptomonas sp. supported complete ontogenesis of nauplii to adults, whereas both strains of C. reinhardii were inadequate for the development of nauplii and copepodites and resulted in high mortality. The nutritional deficiency of both strains of C. reinhardii was compensated for by Cryptomonas sp. when the latter constituted ≥50% of dietary carbon. Pulses of Cryptomonas sp. had a similar compensatory effect.
3. In comparison to Cryptomonas sp., both strains of C. reinhardii were deficient in the three highly unsaturated fatty acids (HUFAs) stearidonic, eicosapentaenoic and docosahexaenoic acid. We manipulated the fatty acid content of C. reinhardii by externally adding these three HUFAs to the alga so that the fatty acid profile resembled that of Cryptomonas sp. This supplementation did not improve food quality, however, indicating that the nutritional deficiency of both strains of C. reinhardii for the ontogenesis of E. gracilis is not due to a lack of these three HUFAs. 相似文献
56.
K. Lüning 《Plant biology (Stuttgart, Germany)》1991,104(2):157-162
A circannual rhythm was found in the kelp Pterygophora californica which forms a new blade with a free running period of 7 ? 8 months under constant conditions. Individual plants exposed to cycles of daylength with T = 12, 6, or 3 months performed 1, 2, or 4 growth cycles, respectively, in one calendar year showing the entrainment of the endogenous circannual rhythm. The annual growth cycle also followed a phase shift of the annual cycle of daylength (T = 12 months) by 3 or 6 months. 相似文献
57.
Many cold‐adapted unicellular plants express ice‐active proteins, but at present, only one type of such proteins has been described, and it shows no resemblance to higher plant antifreezes. Here, we describe four isoforms of a second and very active type of extracellular ice‐binding protein (IBP) from a unicellular chlamydomonad alga collected from an Antarctic intertidal location. The alga is a euryhaline psychrophile that, based on sequences of the alpha tubulin gene and an IBP gene, appears to be the same as a snow alga collected on Petrel Island, Antarctica. The IBPs, which do not resemble any known antifreezes, have strong recrystallization inhibition activity and have an ability to slow the drainage of brine from sea ice. These properties, by maintaining liquid environments, may increase survival of the cells in freezing environments. The IBPs have a repeating TXT motif, which has previously been implicated in ice binding in insect antifreezes and a ryegrass antifreeze. 相似文献
58.
C. J. BAND B. O. ARREDONDO-VEGA R. VAZQUEZ-DUHALT† H. GREPPIN† 《Plant, cell & environment》1992,15(1):129-133
Abstract. The edaphic microalga Neochloris oleoabundans (isolated from desert soil) was subjected to a salt-osmotic shock from 0 to 0·6 kmol m−3 NaCl. The effect of the osmotic upshock on the cell composition was determined. The cell dry weight and the lipid, glycerol and soluble amino acids contents remained unchanged during 5d of osmotic upshock. The protein content increased after 2d of initial osmotic shock, and it appears to be a long-term haloadaptation process of the cells. The most important short-term effects of salt osmotic upshock were a decrease in polysaccharide content and an increase in the soluble carbohydrate content of Neochloris oleoabundans cells. Within the first 4h after the initial shock, there was a transfer of carbon units from polysaccharides to sucrose which was independent of photosynthesis. The increase of intracellular concentration of sucrose contributed to cell osmoregulation. 相似文献
59.
Lars Olof Björn 《Photosynthesis research》1995,46(1-2):203-206
Photosynthesis in light which is so weak that excitation rates are comparable to the decay rates of S-states is modelled. It is found that oxygen evolution rate varies in a non-linear way with Photosystem II excitation rate in this region, but asymptotically approaches a linear relationship (with a slope of one oxygen molecule per four excitations) as excitation rate increases. The asymptote gives an intercept (zero oxygen evolution rate) on the excitation rate axis. The question is raised, whether this model is compatible with photoautotrophy in a red alga found at 268 m depth and able to carry out photosynthesis in extremely weak light. It is found that no unorthodox mechanisms for the S-cycle in this alga have to be assumed to explain its performance. 相似文献
60.
Cell volumes and intracellular concentrations of major solutes of Chlorococcum submarinum were determined before and after salinity shocks. Cells were found to shrink in size by about 30% following changes from 0.1 to 0.5 M NaCl, there was a transitory increase in sodium concentration and more permanent increases in concentrations of potassium, proline and glycerol (the major osmolyte). Conversely, cells doubled in size after the reciprocal downshock, there was rapid loss of about 70% of the cells' glycerol to the medium, a much smaller loss of cellular potassium and a steady disappearance of proline from the cells. The respiratory and photosynthetic responses to salinity fluctuations were also studied. Salinity downshocks stimulated respiration by 30% and inhibited photosynthesis by 16% within 5 min, but within 2 h these rates were identical to control rates. Upshocks caused a slight inhibition of respiration, but decreased photosynthesis by 40% within 5 min and recovery took 2 h. Downshocks had little effect on chlorophyll fluorescence, however, Fo strongly increased and both Fm and Fv/Fm declined within 5 min of salinity increases. This is consistent with a decrease in efficiency of PS2. Ecological and metabolic implications of the results are discussed.Abbreviations DMSO
dimethyl sulphoxide
- Hepes
N-[2-hydroxyethyl]piperazine-N-2-ethane sulphonic acid
- TCA
trichloroacetic acid
- Tris
tris[hydroxymethyl]aminoethane 相似文献