A New Technique for Photobiont Culturing and Manipulation

Goldsmith, S.; Thomas, Michael A.; Gries, Corinna

doi:10.1017/s0024282997000698

Cited by 13 publications

(6 citation statements)

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“…The final cell density was adjusted with sterilised medium to 10 6 cells/ml. Inoculation proceeded by applying 50 ll of this suspension on sterile cellulose-acetate discs then placed on agar Trebouxia medium in Petri plates (Goldsmith et al 1997). All experiments were carried out 21 days after inoculation.…”

Section: Biological Materialsmentioning

confidence: 99%

Dehydration rate and time of desiccation affect recovery of the lichenic algae Trebouxia erici: alternative and classical protective mechanisms

Gasulla

Nova

Esteban

et al. 2009

Planta

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The mechanisms involved in desiccation tolerance of lichens and their photobionts are still poorly understood. To better understand these mechanisms we have studied dehydration rate and desiccation time in Trebouxia, the most abundant chlorophytic photobiont in lichen. Our findings indicate that the drying rate has a profound effect on the recovery of photosynthetic activity of algae after rehydration, greater than the effects of desiccation duration. The basal fluorescence (F'(o)) values in desiccated algae were significantly higher after rapid dehydration, than after slow dehydration, suggesting higher levels of light energy dissipation in slow-dried algae. Higher values of PSII electron transport were recovered after rehydration of slow-dried Trebouxia erici compared to rapid-dried algae. The main component of non-photochemical quenching after slow dehydration was energy dependent (q (E)), whereas after fast dehydration it was photoinhibition (q (I)). Although q (E) seems to play a role during desiccation recovery, no significant variations were detected in the xanthophyll cycle components. Desiccation did not affect PSI functionality. Classical antioxidant activities like superoxide dismutase or peroxidase decreased during desiccation and early recovery. Dehydrins were detected in the lichen-forming algae T. erici and were constitutively expressed. There is probably a minimal period required to develop strategies which will facilitate transition to the desiccated state in this algae. In this process, the xanthophyll cycle and classical antioxidant mechanisms play a very limited role, if any. However, our results indicate that there is an alternative mechanism of light energy dissipation during desiccation, where activation is dependent on a sufficiently slow dehydration rate.

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Section: Biological Materialsmentioning

confidence: 99%

Dehydration rate and time of desiccation affect recovery of the lichenic algae Trebouxia erici: alternative and classical protective mechanisms

Gasulla

Nova

Esteban

et al. 2009

Planta

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“…Stock cultures of the alga were maintained on 3 N Bold's Basal Medium (BBM3 N) supplemented with 10 g casein and 20 g glucose per litre (Ahmadjian ) at 20 °C under a 12 h photoperiod with 30 μ mol m −2 s −1 white‐light illumination. Culture inoculation was achieved by placing 50 μ L of the quantified cell suspension onto sterile cellulose‐acetate discs placed on Asterochloris agar medium as described by Goldsmith, Thomas & Gries (). All experiments were performed 21 d after inoculation.…”

Section: Methodsmentioning

confidence: 99%

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

Gasulla

Jain

Barreno

et al. 2013

Plant Cell & Environment

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The study of desiccation tolerance of lichens, and of their chlorobionts in particular, has frequently focused on the antioxidant system that protects the cell against photo-oxidative stress during dehydration/rehydration cycles. In this study, we used proteomic and transcript analyses to assess the changes associated with desiccation in the isolated phycobiont Asterochloris erici. Algae were dried either slowly (5-6 h) or rapidly (<60 min), and rehydrated after 24 h in the desiccated state. To identify proteins that accumulated during the drying or rehydration processes, we employed two-dimensional (2D) difference gel electrophoresis (DIGE) coupled with individual protein identification using trypsin digestion and liquid chromatography-tandem mass spectrometry (LC-MS/ MS). Proteomic analyses revealed that desiccation caused an increase in relative abundance of only 11-13 proteins, regardless of drying rate, involved in glycolysis, cellular protection, cytoskeleton, cell cycle, and targeting and degradation. Transcripts of five Hsp90 and two b-tubulin genes accumulated primarily at the end of the dehydration process. In addition, transmission electron microscopy (TEM) images indicate that ultrastructural cell injuries, perhaps resulting from physical or mechanical stress rather than metabolic damage, were more intense after rapid dehydration. This occurred with no major change in the proteome. These results suggest that desiccation tolerance of A. erici is achieved by constitutive mechanisms.

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“…An axenic strain of the lichen photobiont Asterochloris erici (Ahmadjian) Skaloud et Peksa (SAG 32.85 = UTEX 911) was used for this study. Algae were grown on cellulose-acetate discs on agar BBM3N containing 10 g casein and 20 g glucose per liter [ 29 , 30 ]. Cultures were maintained at 20°C under a 12 h photoperiod with 30 μmol m -2 s -1 white-light illumination.…”

Section: Methodsmentioning

confidence: 99%

Fungal-associated NO is involved in the regulation of oxidative stress during rehydration in lichen symbiosis

et al. 2010

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BackgroundReactive oxygen species (ROS) are normally produced in respiratory and photosynthetic electron chains and their production is enhanced during desiccation/rehydration. Nitric oxide (NO) is a ubiquitous and multifaceted molecule involved in cell signaling and abiotic stress. Lichens are poikilohydrous organisms that can survive continuous cycles of desiccation and rehydration. Although the production of ROS and NO was recently demonstrated during lichen rehydration, the functions of these compounds are unknown. The aim of this study was to analyze the role of NO during rehydration of the lichen Ramalina farinacea (L.) Ach., its isolated photobiont partner Trebouxia sp. and Asterochloris erici (Ahmadjian) Skaloud et Peksa (SAG 32.85 = UTEX 911).ResultsRehydration of R. farinacea caused the release of ROS and NO evidenced by the fluorescent probes DCFH2-DA and DAN respectively. However, a minimum in lipid peroxidation (MDA) was observed 2 h post-rehydration. The inhibition of NO in lichen thalli with c-PTIO resulted in increases in both ROS production and lipid peroxidation, which now peaked at 3 h, together with decreases in chlorophyll autofluorescence and algal photobleaching upon confocal laser incidence. Trebouxia sp. photobionts generate peaks of NO-endproducts in suspension and show high rates of photobleaching and ROS production under NO inhibition which also caused a significant decrease in photosynthetic activity of A. erici axenic cultures, probably due to the higher levels of photo-oxidative stress.ConclusionsMycobiont derived NO has an important role in the regulation of oxidative stress and in the photo-oxidative protection of photobionts in lichen thalli. The results point to the importance of NO in the early stages of lichen rehydration.

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A New Technique for Photobiont Culturing and Manipulation

Cited by 13 publications

References 0 publications

Dehydration rate and time of desiccation affect recovery of the lichenic algae Trebouxia erici: alternative and classical protective mechanisms

Dehydration rate and time of desiccation affect recovery of the lichenic algae Trebouxia erici: alternative and classical protective mechanisms

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

Fungal-associated NO is involved in the regulation of oxidative stress during rehydration in lichen symbiosis

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