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  • 1
    Electronic Resource
    Electronic Resource
    Etiology of infectious diseases in cultivated Chondrus crispus (Gigartinales, Rhodophyta) (1996)
    Springer
    Hydrobiologia 326-327 (1996), S. 97-104 
    Details
    ISSN: 1573-5117
    Keywords: Acrochaete ; bacteria ; Chondrus crispus ; Cytophaga ; diseases ; Flavobacterium ; fungi ; nematodes ; pathogens ; Petersenia ; potentiating factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The appearance of cavities and holes in fronds of commercially cultivated Chondrus crispus is described. These ultimately arise from the ravages of a ‘green spot’ or ‘green rot’ disease system in which several biotic agents can participate. Nematodes capable of bacterial grazing were recovered from necrotic lesions and we suggest that the nematodes can facilitate wound healing in diseased tissues. Bacteria isolated from disease lesions and from the surfaces of healthy fronds were screened for pathogenic strains. A particularly virulent one, the DOR isolate, was purified from small dark orange colored colonies grown on dilution plates. It was present in necrotic tissue and also recovered from surface scrapings of old healthy fronds, but not from their apical regions. Growth of the DOR isolate appeared to be inhibited by other bacteria colonizing the algal surface. It was shown to be a facultative pathogen, the virulence of which depended on the availability of ammonium or constituents easily metabolized to ammonium. It induced green rot disease in healthy C. crispus and was recoverable in pathogenic form from experimentally infected frond apices. A wound, disease and recovery cycle is discussed to illustrate potential interrelationships involving animal grazers, algal endophytes, Petersenia pollagaster, bacteria and nematodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047793
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  • 2
    Electronic Resource
    Electronic Resource
    Fusion and histocompatibility in Rhodophyta (1996)
    Springer
    Hydrobiologia 326-327 (1996), S. 387-392 
    Details
    ISSN: 1573-5117
    Keywords: fusion ; histocompatibility ; Rhodophyta ; seaweed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fully developed thalli of Chondrus crispus, Gracilaria chilensis, Gymnogongrus furcellatus and Mazzaella laminarioides were used to assess tissue compatibility. The effect of thallus polarity on grafting and regeneration was also evaluated. Fusion did occur between fragments of the same life history phase in C. crispus, G. chilensis, G. furcellatus and M. laminarioides. Fusion between sporophytic and gametophytic tissue occurred in C. crispus, G. chilensis and M. laminarioides. Intergeneric fusion was observed between C. crispus and M. laminarioides, but not between G. chilensis and G. furcellatus. Outer cell wall, cortex and medulla were continuous at the contact face in compatible combinations. Medullary cells in the attached fragments were thinner and longer than normal cells, forming an interwoven scar plate. Thallus polarity did not modify fusion and regeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047836
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  • 3
    Electronic Resource
    Electronic Resource
    Recent advances in the understanding of the biological basis for Gigartina skottsbergii (Rhodophyta) cultivation in Chile (1999)
    Springer
    Hydrobiologia 398-399 (1999), S. 427-434 
    Details
    ISSN: 1573-5117
    Keywords: carrageenophytes ; cultivation ; Gigartina skottsbergii ; population dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The demand in Chile for carrageenophytic algae has increased strongly during the last 3 years, with emphasis on Gigartina skottsbergii, a species representing landings of 32438 t (wet) during 1996. Various sources of information indicate that this species is being over-exploited and therefore the development of cultivation technologies is needed to support the local carrageenan industry. In this study we summarize currently available information on laboratory, outdoor tank and open sea culture of G. skottsbergii. The results indicate that viable spores of G. skottsbergii can be obtained, mainly during winter, with germination rates of both tetraspores and carpospores, up to 40%. Germlings of G. skottsbergii were succesfully transplanted from the laboratory to outdoor tanks, where they displayed survival values higher than 80% during spring. Experimental trials in the field indicate that G. skottsbergii can be cultivated on rope systems, with tissue fragments used as inoculum. This last result suggests that regeneration from fragments is an alternative method for propagation and massive cultivation of G. skottsbergii in Chile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017052015427
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  • 4
    Electronic Resource
    Electronic Resource
    Ecological aspects of algal infectious diseases (1996)
    Springer
    Hydrobiologia 326-327 (1996), S. 89-95 
    Details
    ISSN: 1573-5117
    Keywords: diseases ; Endophyton ; epidemiology ; Mazzaella ; Pleurocapsa ; seasonality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study reports some epidemiological aspects of the infections of Mazzaella laminarioides by Endophyton sp. and Pleurocapsa sp., the organisms associated with the green patch and deformative diseases respectively. Infections affected an important segment of the host population and persisted throughout the year. The main infecting organism was Endophyton sp. Frequency, density and intensity index showed seasonal variations, with lower values in winter. It is suggested that tissue weakening and changes in the biomechanical properties of the infected individuals could be the responsible for this seasonal pattern of variation. This study demonstrates that, at the host population level, the two life history stages of M. laminarioides are susceptible to the pathogens. We also detected an association between reproduction of the host and infection, although the basis for it are unknown. The two pathogens showed different intra-frond distribution, with Endophyton sp. affecting preferentially the base of the frond. The spatial distribution within the beach was different for each pathogen. The main impact of Pleurocapsa sp. was recorded at the center, more protected sector of the beach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047792
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  • 5
    Electronic Resource
    Electronic Resource
    Diseases in seaweeds: an introduction (1996)
    Springer
    Hydrobiologia 326-327 (1996), S. 87-88 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00047791
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  • 6
    Electronic Resource
    Electronic Resource
    Copper-algae interactions: Inheritance or adaptation? (1996)
    Springer
    Environmental monitoring and assessment 40 (1996), S. 41-54 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This study evaluated the responses of wild, adult plants of Enteromorpha compressa, and their progeny, to various copper concentrations. Experiments were designed to test the hypotheses that: 1) individuals of E. compressa from Caleta Palito, a copper-enriched coastal locality, tolerate higher copper concentrations than those from a place with no history of copper pollution and 2) such copper tolerance is under genetic control and therefore, was an inherited character. Our results indicate that algae which inhabit a copper-enriched environment tolerate higher concentrations of copper than those from waters with low copper concentrations. On the other hand, our results suggest that generalizations regarding heritability of the tolerance to copper do not apply to the Chilean E. compressa, as no differences in growth or rhizoid production were found between the progeny from Caleta Palito and Caleta Zenteno. These findings are an indication that heritability and adaptation may represent alternative strategies used by different populations of the same algal species to tolerate copper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395166
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  • 7
    Electronic Resource
    Electronic Resource
    Copper, Copper Mining Effluents and Grazing as Potential Determinants of Algal Abundance and Diversity in Northern Chile (2000)
    Springer
    Environmental monitoring and assessment 61 (2000), S. 267-283 
    Details
    ISSN: 1573-2959
    Keywords: algal diversity ; coastal water ; copper
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We experimentally tested threealternative hypotheses to explain the low algaldiversity and abundance in an intertidal zonereceiving the effluents of the copper mine El Salvadorin northern Chile. Our results demonstrated thatalgae were able to grow at the levels of dissolvedcopper detected in coastal waters of the area. Duringthe assays, growth and regeneration in several red,green and brown adult algae and juvenile Lessonia nigrescens were normal at copper levels of150 μg L-1 or, in some cases, higher. Wealso found that the coastal sea water mixed with theeffluent was not lethal to algae, although in somecases minor effects on growth were detected. Theseresults indicate that today's low algal diversity andabundance can not be explained by the current copperlevels in the area nor by the effect of the effluent.Exclusion of grazers, however, resulted in a fastcolonization by various algal species. This, togetherwith atypically high grazer density at the areas underthe influence of the effluent, strongly suggests thatherbivory, a factor not directly related to the miningoperation, is likely to be responsible for the lowalgal diversity and abundance in the studied locality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006179424239
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  • 8
    Electronic Resource
    Electronic Resource
    Whitening, thallus decay and fragmentation in Gracilaria chilensis associated with an endophytic amoeba (1995)
    Springer
    Journal of applied phycology 7 (1995), S. 421-425 
    Details
    ISSN: 1573-5176
    Keywords: Amoeba ; decay ; fragmentation ; Gracilaria whitening ; infectious disease ; white rot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Whitening of Gracilaria chilensis, accompanied by tissue softening and thallus fragmentation, was found to be associated with the presence of an endophytic amoeba. Although the symptoms developed originally in green mutant thalli, subsequent infections in the laboratory also affected normal, wild-type G. chilensis. Ultrastructural evidence indicates that the amoebae perforate the host cell walls of both cortical and medullary cells and digest their protoplasm. Feeding by the amoeba appears to involve both phagocytosis and enzymatic digestion of the host tissue. Destruction of the host tissue resulted in large cavities first, followed by thallus fragmentation. No other organism was found during the early stages of thallus invasion by the amoeba, although bacteria may appear once the amoeba reaches the inner tissues of the host.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003800
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  • 9
    Electronic Resource
    Electronic Resource
    Healing and regeneration responses in Gigartina skottsbergii (Rhodophyta, Gigartinales): optimization of vegetative propagation for cultivation (1999)
    Springer
    Journal of applied phycology 11 (1999), S. 315-327 
    Details
    ISSN: 1573-5176
    Keywords: Gigartina skottsbergii ; regeneration ; woundhealing ; vegetative propagation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The red alga Gigartina skottsbergii is becoming increasingly valuable as a resource to providing the raw material for the carrageenan industry established in Chile and elsewhere. As a result, wild stocks of the species are subject to intense harvesting by local fishermen. With the current levels of harvesting, it seems likely that natural stands of G. skottsbergii will soon collapse. Although cultivation seems an alternative, knowledge regarding the biology of the species is exceedingly limited. This study reports the first attempt to determine the optimal conditions for vegetative propagation of this species in the laboratory. For this purpose, the processes of wound healing and regeneration of frond fragments and haptera were studied under controlled conditions of temperature, light, and media strength. Our results demonstrated that excised tissues of G. skottsbergii were able to seal the exposed areas in approximately 20 days, by a wound healing process characterized by a re-differentiation of medullary cells into a normal cortex. Our data also demonstrated that frond fragments are better than haptera for propagation purposes. The development of new cortical tissue at the cut surface is followed, within 60 days, by localized blade-like outgrowths along the repaired area. Furthermore, the healing and regenerative responses in both frond fragments and haptera differed in efficiency according to the various combinations of factors, with optimum of 10–15 °C, 5 ?mol m−2 s−1 and plain seawater or standard SFC medium for the fronds. The two types of responses were negatively affected by seawater enriched with a double concentration of nutrients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008106527820
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  • 10
    Electronic Resource
    Electronic Resource
    Copper, copper mine tailings and their effect on marine algae in Northern Chile (1999)
    Springer
    Journal of applied phycology 11 (1999), S. 57-67 
    Details
    ISSN: 1573-5176
    Keywords: copper ; Chile ; mine tailings ; intertidaldiversity ; algae ; invertebrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Results are presented of a long-term research programme on the effect of copper contamination on biota in Chilean coastal waters. In spite of the magnitude of the copper mining tailings that affected Caleta Palito and surroundings in northern Chile, the effects on the intertidal assemblages remain restricted to a small geographic area. Even within the affected area, the effects are not homogeneous and there is evidence of active recovery in biological diversity in recent few years. Experimental evidence suggests that the current low algal diversity and abundance is strongly influenced by herbivory, although chronic effects of the discharges cannot be ruled out. Cellular changes in Enteromorpha compressa from the impacted area were characterised by abnormal granules in the cytoplasm, though these granules did not contain detectable levels of copper or other heavy metals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008027610826
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