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Heat activation bleaching

Thomas D Hawkins, Mark E Warner
Preconditioning to non-stressful warming can protect some symbiotic cnidarians against the high temperature-induced collapse of their mutualistic endosymbiosis with photosynthetic dinoflagellates (Symbiodinium spp.), a process known as bleaching. Here, we sought to determine if such preconditioning is underpinned by differential regulation of aerobic respiration. We quantified in vivo metabolism and mitochondrial respiratory enzyme activity in the naturally symbiotic sea anemone Exaiptasia pallida preconditioned to 30°C for>7 weeks as well as anemones kept at 26°C...
December 15, 2016: Journal of Experimental Biology
Yao-Pin Lin, Meng-Chen Wu, Yee-Yung Charng
Chlorophyll turns over in green organs during photosystem repair and is salvaged via de- and rephytylation, but the enzyme involved in dephytylation is unknown. We have identified an Arabidopsis thaliana thylakoid protein with a putative hydrolase domain that can dephytylate chlorophyll in vitro and in vivo. The corresponding locus, CHLOROPHYLL DEPHYTYLASE1 (CLD1), was identified by mapping a semidominant, heat-sensitive, missense allele (cld1-1). CLD1 is conserved in oxygenic photosynthetic organisms, sharing structural similarity with pheophytinase, which functions in chlorophyll breakdown during leaf senescence...
December 2016: Plant Cell
Stefanie Pontasch, Paul L Fisher, Thomas Krueger, Sophie Dove, William Leggat, Ove Hoegh-Guldberg, Simon K Davy
Corals at the world's southernmost coral reef of Lord Howe Island (LHI) experience large temperature and light fluctuations and need to deal with periods of cold temperature (< 18 °C), but few studies have investigated how corals are able to cope with these conditions. Our study characterized the response of key photophysiological parameters, as well as photoacclimatory and photoprotective pigments (chlorophylls, xanthophylls and β-carotene), to short-term (5-day) cold stress (~ 15 °C; 7 °C below control) in three LHI coral species hosting distinct Symbiodinium ITS2 types, and compared the coral-symbiont response to that under elevated temperature (~ 29 °C; 7 °C above control)...
November 21, 2016: Journal of Phycology
C Schmidt, D Titelboim, J Brandt, B Herut, S Abramovich, A Almogi-Labin, M Kucera
Bleaching, the loss of algal symbionts, occurs in marine photosymbiotic organisms at water temperatures minimally exceeding average summer SST (sea surface temperatures). Pre-adaptation allows organisms to persist under warmer conditions, providing the tolerance can be carried to new habitats. Here we provide evidence for the existence of such adaptation in the benthic foraminifera Pararotalia calcariformata. This species occurs at a thermally polluted site in the Mediterranean, where water temperatures reach a maxima daily average of 36 °C during the summer...
2016: Scientific Reports
Hagit Kvitt, Hanna Rosenfeld, Dan Tchernov
Recent studies suggest that controlled apoptotic response provides an essential mechanism, enabling corals to respond to global warming and ocean acidification. However, the molecules involved and their functions are still unclear. To better characterize the apoptotic response in basal metazoans, we studied the expression profiles of selected genes that encode for putative pro- and anti-apoptotic mediators in the coral Stylophora pistillata under thermal stress and bleaching conditions. Upon thermal stress, as attested by the elevation of the heat-shock protein gene HSP70's mRNA levels, the expression of all studied genes, including caspase, Bcl-2, Bax, APAF-1 and BI-1, peaked at 6-24 h of thermal stress (hts) and declined at 72 hts...
2016: Scientific Reports
Keren Maor-Landaw, Oren Levy
It is well-established that there is a hierarchy of susceptibilities amongst coral genera during heat-stress. However, molecular mechanisms governing these differences are still poorly understood. Here we explored if specific corals possessing different morphologies and different susceptibilities to heat stress may manifest varied gene expression patterns. We examined expression patterns of seven genes in the branching corals Stylophora pistillata and Acropora eurystoma and additionally in the massive robust coral, Porites sp...
2016: PeerJ
Marco Laurenti, Stefano Bianco, Micaela Castellino, Nadia Garino, Alessandro Virga, Candido F Pirri, Pietro Mandracci
Plastic smart windows are becoming one of the key elements in view of the fabrication of inexpensive, lightweight electrochromic (EC) devices to be integrated in the new generation of high-energy-efficiency buildings and automotive applications. However, fabricating electrochromic devices on polymer substrates requires a reduction of process temperature, so in this work we focus on the development of a completely room-temperature deposition process aimed at the preparation of ITO-coated polycarbonate (PC) structures acting as transparent and conductive plastic supports...
March 2016: ACS Applied Materials & Interfaces
Chavdar Slavov, Verena Schrameyer, Michael Reus, Peter J Ralph, Ross Hill, Claudia Büchel, Anthony W D Larkum, Alfred R Holzwarth
The global rise in sea surface temperatures causes regular exposure of corals to high temperature and high light stress, leading to worldwide disastrous coral bleaching events (loss of symbiotic dinoflagellates (Symbiodinium) from reef-building corals). Our picosecond chlorophyll fluorescence experiments on cultured Symbiodinium clade C cells exposed to coral bleaching conditions uncovered the transformations of the alga's photosynthetic apparatus (PSA) that activate an extremely efficient non-photochemical "super-quenching" mechanism...
June 2016: Biochimica et Biophysica Acta
Mukil Maruthamuthu, Diego Javier Jiménez, Patricia Stevens, Jan Dirk van Elsas
BACKGROUND: Functional metagenomics is a promising strategy for the exploration of the biocatalytic potential of microbiomes in order to uncover novel enzymes for industrial processes (e.g. biorefining or bleaching pulp). Most current methodologies used to screen for enzymes involved in plant biomass degradation are based on the use of single substrates. Moreover, highly diverse environments are used as metagenomic sources. However, such methods suffer from low hit rates of positive clones and hence the discovery of novel enzymatic activities from metagenomes has been hampered...
January 28, 2016: BMC Genomics
Diana C Garcia-Ramon, C Alfonso Molina, Antonio Osuna, Susana Vílchez
In the present work, the local isolate Bacillus pumilus 15.1 has been morphologically and biochemically characterized in order to gain a better understanding of this novel entomopathogenic strain active against Ceratitis capitata. This strain could represent an interesting biothechnological tool for the control of this pest. Here, we report on its nutrient preferences, extracellular enzyme production, motility mechanism, biofilm production, antibiotic suceptibility, natural resistance to chemical and physical insults, and morphology of the vegetative cells and spores...
April 2016: Applied Microbiology and Biotechnology
Bouanane-Darenfed Amel, Boucherba Nawel, Bouacem Khelifa, Gagaoua Mohammed, Joseph Manon, Kebbouche-Gana Salima, Nateche Farida, Hacene Hocine, Ollivier Bernard, Cayol Jean-Luc, Fardeau Marie-Laure
The present study investigates the purification and biochemical characterization of an extracellular thermostable xylanase (called XYN35) from Caldicoprobacter algeriensis sp. nov., strain TH7C1(T), a thermophilic, anaerobic strain isolated from the hydrothermal hot spring of Guelma (Algeria). The maximum xylanase activity recorded after 24 h of incubation at 70 °C and in an optimized medium containing 10 g/L mix birchwood- and oats spelt-xylan was 250 U/mL. The pure protein was obtained after heat treatment (1 h at 70 °C), followed by sequential column chromatographies on Sephacryl S-200 gel filtration and Mono-S Sepharose anion-exchange...
January 2016: Carbohydrate Research
Daisy R Sherin, Kallikat N Rajasekharan
A solvent-free, mechanochemical method for the synthesis of curcumin (1) derived 3,5-bis(styryl)pyrazoles and 3,5-bis(styryl)isoxazole (2a-g) at room temperature, with very short reaction time, is reported. Such earlier structural modifications of curcumin, at its β-diketone unit by transforming it into an isosteric pyrazole or isoxazole unit, required prolonged heating. The evaluation of the antioxidant activity of these compounds, based on DPPH, FRAP, and β-carotene bleaching assays, showed that several of these azoles are better antioxidants than curcumin, with the isoxazole derivative 2g being overall the best...
December 2015: Archiv der Pharmazie
Souraya Boulkour Touioui, Nadia Zaraî Jaouadi, Hadjira Boudjella, Fatma Zohra Ferradji, Mouna Belhoul, Hatem Rekik, Abdelmalek Badis, Samir Bejar, Bassem Jaouadi
Streptomyces sp. strain AH4 exhibited a high ability to produce two extracellular proteases when cultured on a yeast malt-extract (ISP2)-casein-based medium. Pure proteins were obtained after heat treatment (30 min at 70 °C) and ammonium sulphate fractionation (30-60 %), followed by size exclusion HPLC column. Matrix assisted laser desorption ionization-time of flight mass spectrometry analysis revealed that the purified enzymes (named SAPS-P1 and SAPS-P2) were monomers with molecular masses of 36,417.13 and 21,099...
July 2015: World Journal of Microbiology & Biotechnology
Roeland Jozef Gentil De Moor, Jeroen Verheyen, Peter Verheyen, Andrii Diachuk, Maarten August Meire, Peter Jozef De Coster, Mieke De Bruyne, Filip Keulemans
Light and heat increase the reactivity of hydrogen peroxide. There is no evidence that light activation (power bleaching with high-intensity light) results in a more effective bleaching with a longer lasting effect with high concentrated hydrogen peroxide bleaching gels. Laser light differs from conventional light as it requires a laser-target interaction. The interaction takes place in the first instance in the bleaching gel. The second interaction has to be induced in the tooth, more specifically in the dentine...
2015: TheScientificWorldJournal
Alejandro García-Arredondo, Luis J Murillo-Esquivel, Alejandra Rojas, Judith Sanchez-Rodriguez
BACKGROUND: Millepora complanata is a plate-like fire coral common throughout the Caribbean. Contact with this species usually provokes burning pain, erythema and urticariform lesions. Our previous study suggested that the aqueous extract of M. complanata contains non-protein hemolysins that are soluble in water and ethanol. In general, the local damage induced by cnidarian venoms has been associated with hemolysins. The characterization of the effects of these components is important for the understanding of the defense mechanisms of fire corals...
2014: Journal of Venomous Animals and Toxins Including Tropical Diseases
Fatma Kallel, Dorra Driss, Semia Ellouz Chaabouni, Raoudha Ghorbel
A newly isolated Bacterium strain named UEB-FK was selected from Tunisian Sahara, exhibiting the highest clear zone on agar plates containing oat spelt xylan by staining with Congo red. On the basis of 16S rDNA sequence analysis, this strain was identified as Bacillus mojavensis. This strain produced extracellular xylanase. Xylanase from the strain was purified to homogeneity and had an apparent molecular weight of 14 kDa. The K m and V max values of the purified xylanase on oat spelt xylan were 3.85 mg/mL and 250...
January 2015: Applied Biochemistry and Biotechnology
Torsten Meyer, Elizabeth A Edwards
Pulp and paper mills generate large amounts of waste organic matter that may be converted to renewable energy in form of methane. The anaerobic treatment of mill wastewater is widely accepted however, usually only applied to few selected streams. Chemical oxygen demand (COD) removal rates in full-scale reactors range between 30 and 90%, and methane yields are 0.30-0.40 m(3) kg(-1) COD removed. Highest COD removal rates are achieved with condensate streams from chemical pulping (75-90%) and paper mill effluents (60-80%)...
November 15, 2014: Water Research
Mourad Jridi, Imen Lassoued, Rim Nasri, Mohamed Ali Ayadi, Moncef Nasri, Nabil Souissi
Composition, functional properties, and in vitro antioxidant activities of gelatin hydrolysates prepared from cuttlefish skin were investigated. Cuttlefish skin gelatin hydrolysates (CSGHs) were obtained by treatment with crude enzyme preparations from Bacillus licheniformis NH1, Bacillus mojavensis A21, Bacillus subtilis A26, and commercial alcalase. All CSGHs had high protein contents, 74.3-78.3%, and showed excellent solubility (over 90%). CSGH obtained by alcalase demonstrated high antioxidant activities monitored by β-carotene bleaching, DPPH radical scavenging, lipid peroxidation inhibition, and reducing power activity...
2014: BioMed Research International
M Shashi Kumar, B Ramakrishna Goud, Bobby Joseph
INTRODUCTION: The Laundry Department plays an important role in preventing the spread of infection and continuously supplying clean linen to various departments in any hospital. OBJECTIVES OF THE STUDY: To identify existing practices and occupational safety and health (OSH) measures in the Laundry Department and to assess the use of personal protective equipments (PPEs) among health care workers. MATERIALS AND METHODS: A cross-sectional study was carried out in a private tertiary care teaching hospital...
January 2014: Indian Journal of Occupational and Environmental Medicine
Boris Jovanović, Héctor M Guzmán
Increased use of manufactured titanium dioxide nanoparticles (nano-TiO2 ) is causing a rise in their concentration in the aquatic environment, including coral reef ecosystems. Caribbean mountainous star coral (Montastraea faveolata) has frequently been used as a model species to study gene expression during stress and bleaching events. Specimens of M. faveolata were collected in Panama and exposed for 17 d to nano-TiO2 suspensions (0.1 mg L(-1) and 10 mg L(-1) ). Exposure to nano-TiO2 caused significant zooxanthellae expulsion in all the colonies, without mortality...
June 2014: Environmental Toxicology and Chemistry
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