Biosynthesis of cell-wall polysaccharides in a green microalga of the Southern Ocean.

Piro, Gabriella; Manno, Massimiliano; Andreoli, Carlo; Rascio, Nicoletta; Dalessandro, Giuseppe

doi:10.1080/11263509609438374

Cited by 3 publications

(6 citation statements)

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“…5). The morphological change could be connected with the plasticity of the cell wall, made up of more than 90% of matrix polysaccharides and less than 10% of cellulose (Piro et al, 1997). The electrondense bodies, instead, were probably due to glycerol produced due to salinity stress, as already reported for other microalgae (Berube et al, 1999).…”

Section: Infrastructure Pigments Physiology and Biomolecular Data Omentioning

confidence: 55%

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Ecological, physiological, and biomolecular surveys on microalgae from Ross Sea (Antarctica)

Andreoli¹,

Moro

Rocca

et al. 2000

Italian Journal of Zoology

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Results of analyses on pico, nano-and microphytoplankton from the sea-ice of Terra Nova Bay, during austral summer 1995-96, are reported. In this environment, among the 116 taxa that we found, the most abundant were diatoms (102). The interior algal community of the sea-ice was dominated by Fragilariopsis spp., Arcbeomonas areolata, and hypnozygotes of Porella glacialis. In the algal mat at the deeper layer of the ice, however, diatoms showed higher density. Photoautotrophic picoplankton was also present and red-fluorescing cells, small eukaryotes and phycocyanin-rich cyanobacteria prevailed over phycoerythrin-rich cyanobacteria. Besides these data, ultrastructural, physiological and biomolecular surveys on three Antarctic sea water microalgae, of which only Koliella antarctica was known, were also carried out. The 18S rDNA gene sequences of K. antarctica and other closely related species allowed us to verify that the Koliella genus belongs to Trebouxiophyceae, while as regards the other two taxa, one of them was found to belong to the Heterococcus and the other to the Pyramimonas genus. They might be undescribed species of the Southern Ocean. Pyramimonas sp., found in Terra Nova Bay during the austral summer 1998-99, carried trichocysts. Moreover, K. antartica, like Heterococcus sp., showed great ability to live both in fresh water and at different salinities.

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Section: Infrastructure Pigments Physiology and Biomolecular Data Omentioning

confidence: 55%

“…For this microalga, already studied ultrastructurally (Andreoli et al, 1998) and for the chemical composition of its cell wall (Piro et al, 1997), we analysed the growth rate in different environmental conditions and thel8S rDNA gene sequence.…”

Section: Infrastructure Pigments Physiology and Biomolecular Data Omentioning

confidence: 99%

Ecological, physiological, and biomolecular surveys on microalgae from Ross Sea (Antarctica)

Andreoli¹,

Moro

Rocca

et al. 2000

Italian Journal of Zoology

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“…In recent years, extensive studies have been performed to gain information on the morphology, physiology and biochemistry of the green microalga K. antarctica (Andreoli et al, 1991(Andreoli et al, , 1998Piro et al, 1997Piro et al, , 2000Giacometti et al, 2001;Zanetti et al, 2001;Vona et al, 2004;Baldisserotto et al, 2005a;Lenucci et al, 2006;Di Martino Rigano et al, 2006). The constancy of the strain is ensured by parallel surveys performed in different laboratories in Italy, including those of the Department of Biology at Padua University, where the organism had been isolated and classified and has been maintained in stable liquid culture (Andreoli et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…The strong environmental pressures in the Antarctic sea have selected interesting adaptive abilities in this organism. For instance, the peculiar composition of the cell wall, formed by a loose network of cellulose micro-fibrils in an extended matrix (Piro et al, 1997(Piro et al, , 2000, ensures a singular plasticity, which allows K. antarctica to change cell shape under different salinities, from 5 to 70, reflecting acclimation to different situations linked to melting or formation of ice in seawater . Moreover, overall cell structures are well adapted to operate efficiently at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Acclimation to darkness in the marine chlorophyteKoliella antarcticacultured under low salinity: hypotheses on its origin in the polar environment

Ferroni

Baldisserotto

Zennaro

et al. 2007

European Journal of Phycology

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2007) Acclimation to darkness in the marine chlorophyte Koliella antarctica cultured under low salinity: hypotheses on its origin in the polar environment, European Journal of Phycology, 42:1, 91-104, In order to obtain new insights on the origin and physiology of the marine chlorophyte Koliella antarctica, the response of the microalga was studied at a salinity of 0.2 in the light and during a 60-day dark period. In light conditions, the alga grows and maintains a functional cell organization. In darkness, the chloroplast-to-chromoplast transition, previously described during dark-acclimation in K. antarctica under a salinity of 34 was only partially triggered; thylakoid lamellae became re-organized into short bundles, but storage substructures were almost completely missing. Microspectrofluorometry, pigment analyses, and morphological observations revealed dark-induced degradation of photosystem II (PSII) with relative stability in the lightharvesting complex (LHCII). Chromatin condensation, mitochondrion fragmentation and material digestion in vacuoles were similar to morphological hallmarks of programmed cell death (PCD), but only 30% of cells underwent cell death and, at the end of the experiment, only 1-2% of cells were TUNEL-positive. Rapid recovery in culture growth after exposure to light showed that the changes apparent in the rest of cells were reversible. Taking into account the response of the plastid and assuming an adaptive benefit of PCD, our results are consistent with the hypothesis that K. antarctica evolved from an Antarctic freshwater ancestor.

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“…A series of studies was undertaken on Koliella antarctica (Andreoli et al, 1998), a green marine microalga recently assigned to Trebouxiophyceae (Andreoli et al, 2000), which is adapted to conditions of very low light intensity in the Ross Sea (Antarctica), where polar nights are characterized by a long twilight and a 3-mo period of complete darkness. The first studies on the morphological and biochemical characterization of the alga were published by Andreoli et al (1998Andreoli et al ( , 2000, Piro et al (1997Piro et al ( , 2000, and Zanetti et al (2001). Our attention was focused on the morphological and biochemical variations that occur in the photosynthetic apparatus when the alga, grown under low light conditions similar to that of the field, is exposed to 3 mo of complete darkness under a simulated austral night condition.…”

Section: Introductionmentioning

confidence: 99%

Dark-acclimation of the Chloroplast in Koliella antarctica Exposed to a Simulated Austral Night Condition

Baldisserotto

Ferroni

Andreoli

et al. 2005

Arctic, Antarctic, and Alpine Research

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Biosynthesis of cell-wall polysaccharides in a green microalga of the Southern Ocean.

Cited by 3 publications

References 1 publication

Ecological, physiological, and biomolecular surveys on microalgae from Ross Sea (Antarctica)

Ecological, physiological, and biomolecular surveys on microalgae from Ross Sea (Antarctica)

Acclimation to darkness in the marine chlorophyteKoliella antarcticacultured under low salinity: hypotheses on its origin in the polar environment

Dark-acclimation of the Chloroplast in Koliella antarctica Exposed to a Simulated Austral Night Condition

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