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  • 1
    Electronic Resource
    Electronic Resource
    Unique Golgi apparatus and vesicle formation in a red alga (1976)
    [s.l.] : Nature Publishing Group
    Nature 259 (1976), S. 566-567 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sexual plants of Polysiphonia novae-angliae Taylor were collected in July 1972, at Naushon Island, and in June 1973, at West Falmouth, Massachusetts. The methods used to prepare for electron microscopy have been described before4. Figure 1 shows completely differentiated Golgi active in the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/259566a0
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of mannitol metabolism in the mangrove red algaCaloglossa leprieurii (Montagne) J.Agardh (1997)
    Springer
    Planta 201 (1997), S. 173-178 
    Details
    ISSN: 1432-2048
    Keywords: Caloglossa ; Hexokinase ; Mannitol-1-phosphate dehydrogenase ; Mannitol-1-phosphatase ; Mannitol dehydrogenase ; Osmolyte metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A metabolic pathway, known as the mannitol cycle in fungi, has been identified as a new entity in the eulittoral mangrove red algaCaloglossa leprieurii (Montagne) J. Agardh. Three specific enzymes, mannitol-1-phosphate dehydrogenase (Mt1PDH; EC 1.1.1.17), mannitol-1-phosphatase (MtlPase; EC 3.1.3.22), mannitol dehydrogenase (MtDH; EC 1.1.1.67) and one nonspecific hexokinase (HK; EC 2.7.1.1) were determined and biochemically characterized in cell-free extracts. Mannitol-1-phosphate dehydrogenase showed activity maxima at pH 7.0 [fructose-6-phosphate (F6P) reduction] and pH 8.5 [oxidation of mannitol-1-phosphate (Mt1P)], and a very high specificity for both carbohydrate substrates. TheK m values were 1.4 mM for F6P, 0.09 mM for MOP, 0.020 mM for NADH and 0.023 mM for NAD+. For the dephosphorylation of MOP, MtlPase exhibited a pH optimum at 7.2, aK m value of 1.2 mM and a high requirement of Mg2+ for activation. Mannitol dehydrogenase had activity maxima at pH 7.0 (fructose reduction) and pH 9.8 (mannitol oxidation), and was less substrate-specific than Mt1PDH and MtlPase, i.e. it also catalyzed reactions in the oxidative direction with arabitol (64.9%), sorbitol (31%) and xylitol (24.8%). This enzyme showedK m values of 39 mM for fructose, 7.9 mM for mannitol, 0.14 mM for NADH and 0.075 mM for NAD+. For the non-specific HK, only theK m values for fructose (0.19 mM) and glucose (7.5 mM) were determined. The activities of the anabolic enzymes Mt1PDH and MtlPase were always at least two orders of magnitude higher than those of the degradative enzymes, indicating a net carbon flow towards a high intracellular mannitol pool. The function of mannitol metabolism inC. leprieurii as a biochemical adaptation to the environmental extremes in the mangrove habitat is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007701
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  • 3
    Electronic Resource
    Electronic Resource
    Light and electron microscopic observations on red algal galls (1974)
    Springer
    Protoplasma 79 (1974), S. 249-264 
    Details
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Lobocolax deformans Howe was found to be a bacterial gall onPrionitis lanceolata. Rodshaped bacteria were distributed throughout the gall in intercellular locations. Algal cells in the gall area exhibited numerous proplastids and irregular cell walls. Bacterial cells were also found in galls located onPolyneuropsis stolonifera (gen. et sp. nov.). These elongated and sometimes branched bacteria occur primarily in the outer areas of the gall. As inLobocolax the cells contained numerous proplastids, however, a large increase in the amount of ER was also noted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276605
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  • 4
    Electronic Resource
    Electronic Resource
    Reproductive biology of Stictosiphonia hookeri (Rhodomelaceae, Rhodophyta) from Argentina, Chile, South Africa and Australia in laboratory culture (1996)
    Springer
    Hydrobiologia 326-327 (1996), S. 277-282 
    Details
    ISSN: 1573-5117
    Keywords: bisexual ; Polysiphonia-type life history ; Rhodophyta ; Stictosiphonia hookeri ; temperature-controlled reproduction ; unisexual
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The red alga Stictosiphonia hookeri is epilithic in shaded habitats of the upper intertidal zone from 30 to 55° S. Thalli of this species from Argentina, Chile, South Africa and Australia, usually without reproductive structures when collected, all developed tetrasporangia in culture. Although good vegetative growth occurred in all nine isolates at 20–25 °C, 12:12 light: dark cycle, 10–30 µmol photons m−2 s−1, none reproduced in these conditions except one isolate from Australia. At 15 °C the four South African (34 °S) isolates developed tetrasporangial stichidia, and three completed a Polysiphonia-type life history. Gametophytes were unisexual or bisexual. At 15 °C one isolate from Chile (36 °S) formed tetrasporangia, but sporelings were not viable. At 10 °C isolates from Argentina and Chile (53 °S and 54 °S) formed tetrasporangia; however, only the Chile isolate completed a Polysiphonia-type life history with unisexual gametophytes. The temperature required to induce sporogenesis correlates with the range of water and air temperatures in the natural habitats of each isolate. In irradiances 〉50 µmol m−2 s−1 the thalli became yellow- brown within two weeks because of phycobiliprotein loss, but this did not impair growth or reproduction. The Argentina and Chile isolates were resistant to freezing in seawater for at least two days, showing no cell damage. The protein cuticle of the outer cell wall is repeatedly shed in culture. This may serve to minimize the attachment of epiphytes in the field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047819
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  • 5
    Electronic Resource
    Electronic Resource
    The fine structure of the parasitic dinoflagellateHaplozoon axiothellae (1974)
    Springer
    Protoplasma 81 (1974), S. 17-35 
    Details
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The multicellular parasitic dinoflagellateHaplozoon axiothellae Siebert was studied with electron microscopy. The trophocyte (attachment cell) bears a suction apparatus with a movable protruding stylet that penetrates the epithelial cell of the host gut. The gonocytes are binucleate and divide frequently. Nuclear structure is similar to the mesokaryotic condition of other dinoflagellates although the chromosomes lack the helically coiled appearance of the DNA fibrils. During nuclear division the nucleus retains its envelope intact and cytoplasmic invaginations develop in which packets of parallel microtubules occur. The microtubules attach to the nuclear envelope opposite the site of chromosome attachment. The chromosomes remain condensed during interphase but the helically coiled DNA fibrils characteristic of the mesokaryotic condition are not evident. The theca which encloses all cells is composed of elements similar to those of typical free-living dinoflagellates, the outer cell membrane and flattened vesicles which contain either flat thin plates or larger spines. No subthecal microtubules are present. The theca grows inward following nuclear division and separates the daughter cells. Trichocysts, pusules, flagellar structures and chloroplasts are not present. The relationship ofHaplozoon to other free-living and parasitic dinoflagellates is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02055771
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  • 6
    Electronic Resource
    Electronic Resource
    The distribution and temporal dynamics of the estuarine macroalgal community of San Francisco Bay (1985)
    Springer
    Hydrobiologia 129 (1985), S. 139-152 
    Details
    ISSN: 1573-5117
    Keywords: San Francisco Bay ; macroalgae ; distribution ; estuary ; algal blooms ; intertidal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Long-term sampling of intertidal macroalgae along permanently marked transects within San Francisco Bay has shown a marked decline in overall species number along the estuarine gradient from the ocean to the river, presumably as a result of decreasing salinity and a progressive lack of hard substrata in the upstream direction. Green algae penetrated further landward than either brown or red species. Seasonally, macroalgal species diversity is lowest during the winter-spring months when salinity, temperature, and irradiance are at yearly minima. Macroalgal abundance as measured by percent cover was maximum during the late spring near the mouth of the estuary and during late summer towards the head. The seasonal increase in algal abundance is related to increasing salinity, temperature, and light availability to the bottom. The summer increase in irradiance is due to the longer photoperiod, increased frequency of day-time low tides, and reduced levels of suspended sediments. The aperiodic occurrence of algal blooms in San Pablo Bay may be caused by a combination of physical factors which are ultimately associated with the river inflow. A hypothesis based on interannual differences in river inflow and the contribution of phytoplankton to nutrient cycles in the benthos is presented to explain the occurrence of nuisance algal blooms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048692
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