265 research outputs found
Updates to some names used for microalgal taxa in Australia
[No abstract available
Rapid colour changes in Euglena sanguinea (Euglenophyceae) caused by internal lipid globule migration
The accumulation of red pigments under chronic stress is a response observed in most
groups of oxygenic photoautotrophs. It is thought that the red pigments in the cell shield
the chlorophyll located underneath from the light. Among these red pigments, the
accumulation of carotenoids is one of the most frequent cases. However, the synthesis
or degradation of carotenoids is a slow process and this response is usually only
observed when the stress is maintained over a period of time. In the Euglenophyte
Euglena sanguinea, this is due to the accumulation of a large amount of free and
esterified astaxanthin (representing 80% of the carotenoid pool). While reddening is a
slow and sometimes irreversible process in other phototrophs, reducing the efficiency of
light harvesting by chlorophyll, in E. sanguinea it is highly dynamic, capable of shifting
from red to green (and vice-versa) in 10-20 min. This change is not due to de novo
carotenogenesis, but to the relocation of cytoplasmic lipid globules where astaxanthin
accumulates. Thus, red globules migrate from the centre of the cell to peripheral
locations when photoprotection is demanded. This protective system seems to be so
efficient that other classical mechanisms are not operative in this species. For example,
despite the presence and operation of the diadino-diatoxanthin cycle, nonphotochemical
quenching (NPQ) is almost undetectable. Since E. sanguinea forms
extensive floating colonies, reddening can be observed at much greater scale than at a
cellular level, the mechanism described here being one of the fastest and most dramatic
colour changes attributable to photosynthetic organisms at cell and landscape level. In
sum, these data indicate an extremely dynamic and efficient photoprotective mechanism
based on organelle migration more than on carotenoid biosynthesis that prevents excess
light absorption by chlorophylls reducing the need for other protective processes related
to energy dissipation.This work was supported by the Basque Government [UPV/EHU-GV IT-1018-16] [UPV/EHU PPG17/67 â GV IT-1040-16], and by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Research and Development Foundation (FEDER) through (i) [CTM2014-53902-C2-2-P] national grant and (ii) a âJuan de la Cierva-IncorporaciĂłnâ postdoctoral grant [IJCI-2014-22489] to BFM
The CCAP knowledgebase:Linking protistan and cyanobacterial biological resources with taxonomic and molecular data
Peer reviewedPublisher PD
Nanoscale Mechanical Characterisation of Amyloid Fibrils Discovered in a Natural Adhesive
Using the atomic force microscope, we have investigated the nanoscale mechanical response of the attachment adhesive of the terrestrial alga Prasiola linearis (Prasiolales, Chlorophyta). We were able to locate and extend highly ordered mechanical structures directly from the natural adhesive matrix of the living plant. The in vivo mechanical response of the structured biopolymer often displayed the repetitive sawtooth force-extension characteristics of a material exhibiting high mechanical strength at the molecular level. Mechanical and histological evidence leads us to propose a mechanism for mechanical strength in our sample based on amyloid fibrils. These proteinaceous, pleated ÎČ-sheet complexes are usually associated with neurodegenerative diseases. However, we now conclude that the amyloid protein quaternary structures detected in our material should be considered as a possible generic mechanism for mechanical strength in natural adhesives
Cassava processing wastewater as a platform for third generation biodiesel production
ABSTRACT This study aimed to evaluate third generation biodiesel production by microalgae Phormidium autumnale using cassava processing wastewater as a platform. Experiments were performed in a heterotrophic bubble column bioreactor. The study focused on the evaluation of the bioreactor (batch and fed-batch) of different operational modes and the analysis of biofuel quality. Results indicate that fed-batch cultivations improved system performance, elevating biomass and oil productions to 12.0 g L−1 and 1.19 g L−1, respectively. The composition of this oil is predominantly saturated (60 %) and monounsaturated (39 %), resulting in a biodiesel that complys with U.S., European and Brazilian standards. The technological route developed indicates potential for sustainable production of bulk oil and biodiesel, through the minimization of water and chemical demands required to support such a process
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