Biochemical and proteomic response of the freshwater green alga Pseudochlorella pringsheimii to iron and salinity stressors.

Background: Pseudochlorella pringsheimii (Ppr) is a green unicellular alga rich with chlorophyll, carotenoids, and antioxidants. As a widespread organism, Ppr must face, and adapt to, many environmental stresses and these are becoming more frequent and more extreme under the conditions of climate change. We therefore focused on salinity induced by NaCl and iron (Fe) variation stresses, which are commonly encountered by algae in their natural environment.

Cooperative antioxidative defense of the blue-green alga Arthrospira (Spirulina) platensis under oxidative stress imposed by exogenous application of hydrogen peroxide.

Hydrogen peroxide (HO) is an environmentally-safe algaecide used to control harmful algal blooms and as a disinfectant in various domestic and industrial applications. It is produced naturally in sunny-water or as a by-product during growth, and metabolism of photosynthetic organisms. To assess the impact of HO on Arthrospira platensis, several biochemical components, and antioxidant enzymes were analysed.

Antioxidant enzymes of Pseudochlorella pringsheimii under two stressors: variation of SOD Isoforms activity.

Algae are always facing the challenge of exposure to different stress conditions, therefore raising challenges of adaptation for survival. In this context, the growth and the antioxidant enzymes of the green stress-tolerant alga Pseudochlorella pringsheimii were investigated under two environmental stresses viz. iron and salinity.

Development and validation of a reliable LC-MS/MS method for quantitative analysis of usnic acid in Cladonia uncialis.

Objective: The purpose of this study was to develop and validate a specific and sensitive liquid chromatography tandem mass-spectrometry method for quantification of usnic acid concentration in the lichen, Cladonia uncialis, suitable for detection of relatively small fluctuations of usnic acid concentration in response to environmental changes.

Results: The resulting method was fully validated according to international guidelines and demonstrated good selectivity and sensitivity with minor levels of a matrix effect and high accuracy.

Molecular characterization and expression analysis of iron superoxide dismutase gene from (Trebouxiophyceae, Chlorophyta).

The FeSOD isoforms of were identified, a preliminary characterization of the enzyme was conducted, and the relationship among the FeSOD gene from and that of other organisms was examined. The FeSOD has an open reading frame of 612 bp that encodes 203 deduced amino acids with a molecular mass of 23 kDa. Expression of the recombinant FeSOD gene was done successfully in .

Tissue-specific localization of polyketide synthase and other associated genes in the lichen, Cladonia rangiferina, using laser microdissection.

The biosynthesis of two polyketides, atranorin and fumarprotocetraric acid, produced from a lichen-forming fungus, Cladonia rangiferina (L.) F. H.

Aerobic anoxygenic phototrophs in gold mine tailings in Nopiming Provincial Park, Manitoba, Canada.

A sampling trip to Central Gold Mine, Nopiming Provincial Park, Canada, was taken in September 2011. Abundance, distribution, and physiology of aerobic anoxygenic phototrophs (AAP) from 4 locations were studied. Enumeration revealed 14.

Identification of 6-Hydroxymellein Synthase and Accessory Genes in the Lichen Cladonia uncialis.

A transcribed polyketide synthase (PKS) gene has been identified in the lichen Cladonia uncialis. The complete nucleotide sequence of this PKS was determined from the amplified cDNA, and an assignment of individual domains was accomplished by homology searching using AntiSMASH. A scan of the complete genome sequence of C.

Algal carbohydrates affect polyketide synthesis of the lichen-forming fungus Cladonia rangiferina.

Lichen secondary metabolites (polyketides) are produced by the fungal partner, but the role of algal carbohydrates in polyketide biosynthesis is not clear. This study examined whether the type and concentration of algal carbohydrate explained differences in polyketide production and gene transcription by a lichen fungus (Cladonia rangiferina). The carbohydrates identified from a free-living cyanobacterium (Spirulina platensis; glucose), a lichen-forming alga (Diplosphaera chodatii; sorbitol) and the lichen alga that associates with C.

Role of pH on antioxidants production by Spirulina (Arthrospira) platensis.

Algae can tolerate a broad range of growing conditions but extreme conditions may lead to the generation of highly dangerous reactive oxygen species (ROS), which may cause the deterioration of cell metabolism and damage cellular components. The antioxidants produced by algae alleviate the harmful effects of ROS. While the enhancement of antioxidant production in blue green algae under stress has been reported, the antioxidant response to changes in pH levels requires further investigation.

Putative identification of the usnic acid biosynthetic gene cluster by de novo whole-genome sequencing of a lichen-forming fungus.

To identify the biosynthetic gene cluster responsible for the biosynthesis of the polyketide usnic acid we carried out the de novo genome sequencing of the fungal partner of Cladonia uncialis. This was followed by comprehensive in silico annotation of polyketide synthase (PKS) genes. The biosynthesis of usnic acid requires a non-reducing PKS possessing a carbon methylation (CMeT) domain, a terminal Claisen cyclase (CLC) domain, and an accompanying oxidative enzyme that dimerizes methylphloracetophenone to usnic acid.

Substratum preference of two species of Xanthoparmelia.

The distribution of established saxicolous lichens has been previously studied but substratum preference and elemental composition has been relatively unexplored. The objectives of this study were to compare ascospore germination and growth for two species of Xanthoparmelia using media supplemented with pulverized rock and to explore photobiont selectivity relative to ecological guilds. Mature apothecia from X.

Tellurite-, tellurate-, and selenite-based anaerobic respiration by strain CM-3 isolated from gold mine tailings.

The newly discovered strain CM-3, a Gram-negative, rod-shaped bacterium from gold mine tailings of the Central Mine in Nopiming Provincial Park, Canada, is capable of dissimilatory anaerobic reduction of tellurite, tellurate, and selenite. CM-3 possesses very high level resistance to these oxides, both aerobically and anaerobically. During aerobic growth, tellurite and tellurate resistance was up to 1500 and 1000 µg/ml, respectively.

Recognition- and defense-related gene expression at 3 resynthesis stages in lichen symbionts.

Recognition and defense responses are early events in plant-pathogen interactions and between lichen symbionts. The effect of elicitors on responses between lichen symbionts is not well understood. The objective of this study was to compare the difference in recognition- and defense-related gene expression as a result of culture extracts (containing secreted water-soluble elicitors) from compatible and incompatible interactions at each of 3 resynthesis stages in the symbionts of Cladonia rangiferina.

Evolution of ketosynthase domains of polyketide synthase genes in the Cladonia chlorophaea species complex (Cladoniaceae).

Lichen-forming fungi synthesize a diversity of polyketides, but only a few non-reducing polyketide synthase (PKS) genes from a lichen-forming fungus have been linked with a specific polyketide. While it is a challenge to link the large number of PKS paralogs in fungi with specific products, it might be expected that the PKS paralogs from closely related species would be similar because of recent evolutionary divergence. The objectives of this study were to reconstruct a PKS gene phylogeny of the Cladonia chlorophaea species complex based on the ketosynthase domain, a species phylogeny of the complex, and to explore the presence of PKS gene paralogs among members of the species complex.

Rehydration conditions for isolation of high quality RNA from the lichen Lobaria pulmonaria.

Background: The poikilohydric nature of lichens enables them to survive repeated episodes of desiccation by utilizing water when it becomes available. During rehydration, RNA-degrading endonucleases may be released, reducing RNA quantity and quality. Re-generation of a steady-state condition where RNA quantity and quality no longer fluctuate establishes a framework for development of new hypotheses for future investigations.

Identification and comparison of the 3 early stages of resynthesis for the lichen Cladonia rangiferina.

A lichen is an association between a biotrophic fungal partner and a green algal and (or) cyanobacterial partner, which may be considered a "controlled" parasitic interaction. While controlled parasitism implies benefit to both interacting partners, a parasitism that is not controlled implies that one partner benefits to the detriment of the other partner. The objective of this study was to compare morphological development of the interaction between Cladonia rangiferina with its compatible algal partner (Asterochloris glomerata/irregularis) and incompatible algae (Coccomyxa peltigerae and Chloroidium ellipsoideum) at 3 early resynthesis stages.

Effect of aposymbiotic conditions on colony growth and secondary metabolite production in the lichen-forming fungus Ramalina dilacerata.

The production of secondary metabolites by aposymbiotic lichen-forming fungi in culture is thought to be influenced by environmental conditions. The effects of the environment may be studied by culturing fungi under defined growing parameters to provide a better understanding of the role of the large number of polyketide synthase (PKS) gene paralogs detected in the genomes of many fungi. The objectives of this study were to examine the effects of culture conditions (media composition and pH level) on the colony growth, the numbers of secondary products, and the expression of two PKS genes by the lichen-forming fungus Ramalina dilacerata.

Molecular Phylogenetic Analysis, Trichothecene Chemotype Patterns, and Variation in Aggressiveness of Fusarium Isolates Causing Head Blight in Wheat.

Certain Fusarium species cause Fusarium head blight (FHB) in wheat and other small grains. Differences in characteristics of the pathogen species/isolates used in breeding programs may affect reaction of host genotypes, leading to erroneous results. To clarify differences among Fusarium isolates from different geographical zones, the phylogenetic, chemotypic, and pathogenic abilities of 58 isolates collected from three wheat-producing countries (Canada, Mexico, and Iran) were investigated.

Photobiont Relationships and Phylogenetic History of Dermatocarpon luridum var. luridum and Related Dermatocarpon Species.

Members of the genus Dermatocarpon are widespread throughout the Northern Hemisphere along the edge of lakes, rivers and streams, and are subject to abiotic conditions reflecting both aquatic and terrestrial environments. Little is known about the evolutionary relationships within the genus and between continents. Investigation of the photobiont(s) associated with sub-aquatic and terrestrial Dermatocarpon species may reveal habitat requirements of the photobiont and the ability for fungal species to share the same photobiont species under different habitat conditions.

Body fluid osmolytes and urea and ammonia flux in the colon of two chondrichthyan fishes, the ratfish, Hydrolagus colliei, and spiny dogfish, Squalus acanthias.

The present study has examined the role of the colon in regulating ammonia and urea nitrogen balance in two species of chondrichthyans, the ratfish, Hydrolagus colliei (a holocephalan) and the spiny dogfish, Squalus acanthias (an elasmobranch). Stripped colonic tissue from both the dogfish and ratfish was mounted in an Ussing chamber and in both species bi-directional urea flux was found to be negligible. Urea uptake by the mucosa and serosa of the isolated colonic epithelium through accumulation of (14)C-urea was determined to be 2.

Fungal farmers or algal escorts: lichen adaptation from the algal perspective.

Domestication of algae by lichen-forming fungi describes the symbiotic relationship between the photosynthetic (green alga or cyanobacterium; photobiont) and fungal (mycobiont) partnership in lichen associations (Goward 1992). The algal domestication implies that the mycobiont cultivates the alga as a monoculture within its thallus, analogous to a farmer cultivating a food crop. However, the initial photobiont 'selection' by the mycobiont may be predetermined by the habitat rather than by the farmer.

In situ imaging of usnic acid in selected Cladonia spp. by vibrational spectroscopy.

In this study, we demonstrate the first in situ detection of usnic acid (UA) in selected species of the lichen Cladonia, using FPA-FTIR imaging and Raman microscopy. Fruticose lichens present a variety of defensive mechanisms, one of which is the production of UA. This polyketide secondary metabolite, produced by certain lichenized fungi, has a protective function for the lichen that includes a strong absorption in the ultraviolet range.