Read by QxMD icon Read


Jürgen Voigt, Markus Morawski, Johannes Wöstemeyer
We have recently reported that protease inhibitors affecting the activity of the proteasome cause necrotic cell death in Chlamydomonas reinhardtii instead of inducing apoptosis as shown for some mammalian cell lines. Therefore, we have studied other well-known inducers of apoptosis in mammalian cells for their effects on C. reinhardtii cells. Mastoparan caused rapid cell death without a prominent lag-phase under all growth conditions, whereas the cytotoxic effect of the topoisomerase I inhibitor camptothecin exclusively occured during the cell-division phase...
March 24, 2017: Journal of Eukaryotic Microbiology
Alejandro Chamizo-Ampudia, Aurora Galvan, Emilio Fernandez, Angel Llamas
The mARC (mitochondrial Amidoxime Reducing Component) proteins are recently discovered molybdenum (Mo) Cofactor containing enzymes. They are involved in the reduction of several N-hydroxylated compounds (NHC) and nitrite. Some NHC are prodrugs containing an amidoxime structure or mutagens such as 6-hydroxylaminopurine (HAP). We have studied this protein in the green alga Chlamydomonas reinhardtii (crARC). Interestingly, all the ARC proteins need the reducing power supplied by other proteins. It is known that crARC requires a cytochrome b₅ (crCytb5-1) and a cytochrome b₅ reductase (crCytb5-R) that form an electron transport chain from NADH to the substrates...
March 21, 2017: International Journal of Molecular Sciences
Ayumi Kinoshita, Yoshimi Niwa, Kiyoshi Onai, Takashi Yamano, Hideya Fukuzawa, Masahiro Ishiura, Takuya Matsuo
The green alga Chlamydomonas reinhardtii shows various light responses in behavior and physiology. One such photoresponse is the circadian clock, which can be reset by external light signals to entrain its oscillation to daily environmental cycles. In a previous report, we suggested that a light-induced degradation of the clock protein ROC15 is a trigger to reset the circadian clock in Chlamydomonas. However, light signaling pathways of this process remained unclear. Here, we screened for mutants that show abnormal ROC15 diurnal rhythms, including the light-induced protein degradation at dawn, using a luciferase fusion reporter...
March 2017: PLoS Genetics
Maxence Plouviez, David Wheeler, Andy Shilton, Michael A Packer, Patricia A McLenachan, Emanuel Sanz-Luque, Francisco Ocaña-Calahorro, Emilio Fernández, Benoit Guieysse
Over the last decades, several studies have reported emissions of nitrous oxide (N2 O) from microalgae cultures and aquatic ecosystems characterized by a high level of algal activity (e.g. eutrophic lakes). As N2 O is a potent greenhouse gas (GHG) and an ozone depleting pollutant, these findings suggest that large scale microalgae cultivation (and possibly, natural eutrophic ecosystems) could have significant environmental impacts. Using the model unicellular microalga Chlamydomonas reinhardtii, this study was conducted to investigate the molecular basis of microalgal N2 O synthesis...
March 23, 2017: Plant Journal: for Cell and Molecular Biology
P Guichard, V Hamel, M Le Guennec, N Banterle, I Iacovache, V Nemčíková, I Flückiger, K N Goldie, H Stahlberg, D Lévy, B Zuber, P Gönczy
How cellular organelles assemble is a fundamental question in biology. The centriole organelle organizes around a nine-fold symmetrical cartwheel structure typically ∼100 nm high comprising a stack of rings that each accommodates nine homodimers of SAS-6 proteins. Whether nine-fold symmetrical ring-like assemblies of SAS-6 proteins harbour more peripheral cartwheel elements is unclear. Furthermore, the mechanisms governing ring stacking are not known. Here we develop a cell-free reconstitution system for core cartwheel assembly...
March 23, 2017: Nature Communications
Thomas Roach, Theresa Baur, Wolfgang Stöggl, Anja Krieger-Liszkay
High light causes photosystem II to generate singlet oxygen ((1) O2 ), a reactive oxygen species (ROS) that can react with membrane lipids, releasing reactive electrophile species (RES), such as acrolein. To investigate how RES may contribute to light stress responses, Chlamydomonas reinhardtii was high light-treated in photoautotrophic and mixotrophic conditions and also in an oxygen-enriched atmosphere to elevate ROS production. The responses were compared to exogenous acrolein. Non-photochemical quenching (NPQ) was higher in photoautotrophic cells, as a consequence of a more de-epoxidized state of the xanthophyll cycle pool and more LHCSR3 protein, showing that photosynthesis was under more pressure than in mixotrophic cells...
March 21, 2017: Physiologia Plantarum
Khorcheska Batyrova, Patrick C Hallenbeck
Chlamydomonas reinhardtii cy6Nac2.49 is a genetically modified algal strain that activates photosynthesis in a cyclical manner, so that photosynthesis is not active constitutively in the presence of oxygen, but is turned on only in response to a metabolic trigger (anaerobiosis). Here, we further investigated hydrogen production by this strain comparing it with the parental wild-type strain under photoheterotrophic conditions in regular tris-acetate-phosphate (TAP) medium with a 10-h:14-h light/dark regime. Unlike the wild-type, whose level of H₂ production remained low during illumination, H₂ production in the mutant strain increased gradually with each subsequent light period, and by the final light period was significantly higher than the wild-type...
March 16, 2017: International Journal of Molecular Sciences
Michael Taschner, André Mourão, Mayanka Awasthi, Jerome Basquin, Esben Lorentzen
Motile cilia are found on unicellular organisms such as the green alga Chlamydomonas reinhardtii, on sperm cells, and on cells that line the trachea and fallopian tubes in mammals. The motility of cilia relies on a number of large protein complexes including the force-generating outer dynein arms (ODAs). The transport of ODAs into cilia has been previously shown to require the transport adaptor ODA16 as well as the intraflagellar transport (IFT) protein IFT46, but the molecular mechanism by which ODAs are recognized and transported into motile cilia is still unclear...
March 15, 2017: Journal of Biological Chemistry
Monika R VanGordon, Gaurav Gyawali, Steven W Rick, Susan B Rempe
Channelrhodopsins (ChR1 and ChR2) are light-activated ion channels that enable photomobility of microalgae from the genus Chlamydomonas. Despite common use of ChR2 in optogenetics for selective control and monitoring of individual neurons in living tissue, the protein structures remain unresolved. Instead, a crystal structure of the ChR chimera (C1C2), an engineered combination of helices I-V from ChR1, without its C-terminus, and helices VI-VII from ChR2, is used as a template for ChR2 structure prediction...
March 14, 2017: Biophysical Journal
Anne Sawyer, Yu Bai, Yinghua Lu, Anja Hemschemeier, Thomas Happe
Molecular hydrogen (H2 ) can be produced in green microalgae by [FeFe]-hydrogenases as a direct product of photosynthesis. The Chlamydomonas reinhardtii hydrogenase HYDA1 contains a catalytic site comprising a classic [4Fe4S] cluster linked to a unique 2Fe sub-cluster. From in vitro studies it appears that the [4Fe4S] cluster is incorporated first by the housekeeping FeS cluster assembly machinery, followed by the 2Fe sub-cluster, whose biosynthesis requires the specific maturases HYDEF and HYDG. To investigate the maturation process in vivo, we expressed HYDA1 from the C...
March 13, 2017: Plant Journal: for Cell and Molecular Biology
Jason M Brown, Matthew Mosley, Daniela Montes-Berrueta, Yuqing Hou, Fan Yang, Chasity Scarbrough, George B Witman, Maureen Wirschell
We have used an insertional mutagenesis approach to generate new C. reinhardtii motility mutants. Of 56 mutants isolated, one is a new allele at the ODA3 locus, called oda3-6. Similar to the previously characterized oda3 alleles, oda3-6 has a slow-jerky swimming phenotype and reduced swimming speed. The oda3-6 mutant fails to assemble the outer dynein arm motor and outer dynein arm-docking complex (ODA-DC) in the ciliary axoneme due to an insertion in the 5' end of the DCC1 gene, which encodes the DC1 subunit of the ODA-DC...
2017: PloS One
Soumita Dutta, Prachee Avasthi
The unicellular green alga Chlamydomonas reinhardtii is an ideal model organism for studies of ciliary function and assembly. In assays for biological and biochemical effects of various factors on flagellar structure and function, synchronous culture is advantageous for minimizing variability. Here, we have characterized a method in which 100% synchronization is achieved with respect to flagellar length but not with respect to the cell cycle. The method requires inducing flagellar regeneration by amputation of the entire cell population and limiting regeneration time...
March 2017: MSphere
Tomohito Yamasaki, Heriberto Cerutti
We have previously reported that the RNA-binding protein Dull slicer 16 (DUS16) plays a key role in the processing of primary miRNAs (pri-miRNAs) in the unicellular green alga Chlamydomonas reinhardtii. In the present report, we elaborate on the interaction of DUS16 with Dicer-like 3 (DCL3) during pri-miRNA processing. Comprehensive analyses of small RNA libraries derived from mutant and wild-type algal strains allowed the de novo prediction of 35 pri-miRNA genes, including 9 previously unknown ones. The pri-miRNAs dependent on DUS16 for processing largely overlapped with those dependent on DCL3...
2017: Communicative & Integrative Biology
M Sendra, P M Yeste, I Moreno-Garrido, J M Gatica, J Blasco
CeO2 nanoparticles (CeO2 NPs) are well-known for their catalytic properties and antioxidant potential. Recent uses in therapy are based on the Ce(+3) ions released by CeO2 NPs. Reactions involving redox cycles between Ce(+3) and Ce(+4) oxidation stage seem to promote scavenging of reactive oxygen species (ROS), thus protecting cells from oxygen damage. However, the internalization of CeO2 NPs and release of Ce(+3) could be responsible for a toxic effect on cells. The literature reports controversial results on the toxicity of CeO2 NPs to phytoplankton...
March 7, 2017: Science of the Total Environment
Kenneth Wei Min Tan, Yuan Kun Lee
Biofuel production from genetically-engineered microalgae is currently among the most widely studied strategies in generating renewable energy. However, microalgae currently suffer from low oil yields which limit the commercial feasibility of industrial-scale production. A major bottleneck in cost-efficient biofuel production from microalgae is the dilemma between biomass productivity and lipid accumulation. When grown under stressful culture conditions such as nitrogen depletion, microalgae accumulate large amounts of neutral lipids, but it comes at the expense of growth which negatively impacts overall lipid productivity...
March 7, 2017: Journal of Biotechnology
Sang-Min Paik, Sang-Jun Sim, Noo Li Jeon
Nutrient deprivation in a batch process induces microbes to produce secondary metabolites while drastically constraining cellular growth. A microfluidic continuous perfusion system was designed and tested to culture microalgae, Chlamydomonas reinhardtii, under constant nutrient concentration slightly lower than normal condition. When cultured in 7.5%/7.5% of NH4(+)/PO4(2)(-), C. reinhardtii showed a 2.4-fold increase in TAG production with a 3.5-fold increase in biomass compared to level obtained under an only NH4(+) depleted condition...
February 14, 2017: Bioresource Technology
Daniela Morales-Sánchez, Yeongho Kim, Ee Leng Terng, Laura Peterson, Heriberto Cerutti
Understanding the unique features of algal metabolism may be necessary to realize the full potential of algae as feedstock for the production of biofuels and biomaterials. Under nitrogen deprivation, the green alga C. reinhardtii showed substantial triacylglycerol (TAG) accumulation and up-regulation of a gene, GPD2, encoding a multidomain enzyme with a putative phosphoserine phosphatase (PSP) motif fused to glycerol-3-phosphate dehydrogenase (GPD) domains. Canonical GPD enzymes catalyze the synthesis of glycerol-3-phosphate (G3P) by reduction of dihydroxyacetone phosphate (DHAP)...
March 8, 2017: Plant Journal: for Cell and Molecular Biology
Christian Santschi, Nadia Von Moos, Volodymyr B Koman, Vera I Slaveykova, Paul Bowen, Olivier J F Martin
Engineered nanomaterials (ENMs) are key drivers for the development of highly sophisticated new technologies. As all new attainments, the rapidly increasing used of ENMs raise concerns about their safety for the environment and humans. There is growing evidence showing that if engineered nanomaterials are released into the environment, there is a possibility that they could cause harm to aquatic microorganisms. Among the divers effects triggering their toxicity the ability of ENMs to generate reactive oxygen species (ROS) capable of oxidizing biomolecules is currently considered a central mechanism of toxicity...
March 7, 2017: Journal of Nanobiotechnology
Dmitriy A Semchonok, K N Sathish Yadav, Pengqi Xu, Bartlomiej Drop, Roberta Croce, Egbert J Boekema
Photosynthetic organisms can thermally dissipate excess of absorbed energy in high-light conditions in a process known as non-photochemical quenching (NPQ). In the green alga Chlamydomonas reinhardtii this process depends on the presence of the light-harvesting protein LHCSR3, which is only expressed in high light. LHCSR3 has been shown to act as a quencher when associated with the Photosystem II supercomplex and to respond to pH changes, but the mechanism of quenching has not been elucidated yet. In this work we have studied the interaction between LHCSR3 and Photosystem II C2S2 supercomplexes by single particle electron microscopy...
March 1, 2017: Biochimica et Biophysica Acta
Raphaëlle Laterre, Mathieu Pottier, Claire Remacle, Marc Boutry
Ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco) is the most abundant enzyme in plants and is responsible for CO2 fixation during photosynthesis. This enzyme is assembled from eight large subunits (RbcL) encoded by a single chloroplast gene, and eight small subunits (RbcS) encoded by a nuclear gene family. Rubisco is primarily found in the chloroplasts of mesophyll (C3 plants), bundle-sheath (C4 plants) and guard cells. In certain species, photosynthesis also takes place in the secretory cells of glandular trichomes, which are epidermal outgrowths (hairs) involved in the secretion of specialized metabolites...
March 1, 2017: Plant Physiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"