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Gerashchenko, Bogdan I., Igor I. Gerashchenko, Toshikazu Kosaka i Hiroshi Hosoya. "Stimulatory effect of aerosil on algal growth". Canadian Journal of Microbiology 48, nr 2 (1.02.2002): 170–75. http://dx.doi.org/10.1139/w01-143.
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Unicellular green alga represents not only a convenient model for its biochemical and physiological studies but also a sensitive system to test the effects of various environmental factors. Algae cells of two strains, SA-3 strain (exsymbiotic from Paramecium bursaria) and Chlorella vulgaris c-27, were asynchronously cultured in the presence of 0.01% Aerosil A-300. Aerosil effects on algae were monitored at logarithmic and stationary phases of their growth by flow cytometry and microscopic counting of algal numbers. The growth patterns of algae were evaluated by their forward light scatter versus fluorescence of endogenous chlorophyll (FL3-height) signal distributions. Although aerosil itself did not cause any direct effects on algal morphology, it affected the growth patterns and the numbers of algae of both strains. Their growth patterns were remarkably altered in the late logarithmic phase cultures (6-day cultures). However, a significant increase of cell numbers was found in the stationary phase cultures (9- and 12-day cultures). While C. vulgaris c-27 demonstrated an increase of cell numbers by approximately 11% in the 9- and 12-day cultures, the amounts of SA-3 cells in the 9- and 12-days cultures were increased by 16% and 35%, respectively. Our study shows aerosil in its colloidal form stimulates proliferation of algae mainly via an acceleration of their life cycles. The stimulatory effect of silica on the growth of algae, the mechanism of which remains to be clarified, might have a practical (e.g., ecological) interest for regulation of algal expansion.Key words: aerosil, cloned algae, growth, forward light scatter, chlorophyll fluorescence.
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Hupp, Bettina, Gabriella Huszár, Attila Farkas i Gergely Maróti. "Algal Hydrogen Production and Exopolysaccharide Patterns in Chlorella–Bacillus Inter-Kingdom Co-Cultures". Fermentation 9, nr 5 (28.04.2023): 424. http://dx.doi.org/10.3390/fermentation9050424.
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Biohydrogen production from wastewater using eukaryotic green algae can be facilitated by appropriately selected bacterial partners and cultivation conditions. Two Chlorella algal species were chosen for these experiments, based on their robust growth ability in synthetic wastewater. The applied three Bacillus bacterial partners showed active respiration and efficient biomass production in the same synthetic wastewater. Bacillus amyloliquefaciens, Bacillus mycoides, and Bacillus cereus as bacterial partners were shown to specifically promote algal biomass yield. Various inter-kingdom co-culture combinations were investigated for algal–bacterial biomass generation, for co-culture-specific exopolysaccharide patterns, and, primarily, for algal biohydrogen evolution. Chlorella sp. MACC-38 mono- and co-cultures generated significantly higher biomass compared with that of Chlorella sp. MACC-360 mono- and co-cultures, while in terms of hydrogen production, Chlorella sp. MACC-360 co-cultures clearly surpassed their Chlorella sp. MACC-38 counterparts. Imaging studies revealed tight physical interactions between the algal and bacterial partners and revealed the formation of co-culture-specific exopolysaccharides. Efficient bacterial respiration was in clear correlation with algal hydrogen production. Stable and sustainable algal hydrogen production was observed in synthetic wastewater for Chlorella sp. MACC-360 green algae in co-cultures with either Bacillus amyloliquefaciens or Bacillus cereus. The highest algal hydrogen yields (30 mL H2 L−1 d−1) were obtained when Chlorella sp. MACC-360 was co-cultured with Bacillus amyloliquefaciens. Further co-culture-specific algal biomolecules such as co-cultivation-specific exopolysaccharides increase the valorization potential of algal–bacterial co-cultures and might contribute to the feasibility of algal biohydrogen production technologies.
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Fisher, Carolyn L., Pamela D. Lane, Marion Russell, Randy Maddalena i Todd W. Lane. "Low Molecular Weight Volatile Organic Compounds Indicate Grazing by the Marine Rotifer Brachionus plicatilis on the Microalgae Microchloropsis salina". Metabolites 10, nr 9 (4.09.2020): 361. http://dx.doi.org/10.3390/metabo10090361.
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Microalgae produce specific chemicals indicative of stress and/or death. The aim of this study was to perform non-destructive monitoring of algal culture systems, in the presence and absence of grazers, to identify potential biomarkers of incipient pond crashes. Here, we report ten volatile organic compounds (VOCs) that are robustly generated by the marine alga, Microchloropsis salina, in the presence and/or absence of the marine grazer, Brachionus plicatilis. We cultured M. salina with and without B. plicatilis and collected in situ volatile headspace samples using thermal desorption tubes over the course of several days. Data from four experiments were aggregated, deconvoluted, and chromatographically aligned to determine VOCs with tentative identifications made via mass spectral library matching. VOCs generated by algae in the presence of actively grazing rotifers were confirmed via pure analytical standards to be pentane, 3-pentanone, 3-methylhexane, and 2-methylfuran. Six other VOCs were less specifically associated with grazing but were still commonly observed between the four replicate experiments. Through this work, we identified four biomarkers of rotifer grazing that indicate algal stress/death. This will aid machine learning algorithms to chemically define and diagnose algal mass production cultures and save algae cultures from imminent crash to make biofuel an alternative energy possibility.
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Šimek, Karel, Vojtěch Kasalický, Eliška Zapomělová i Karel Horňák. "Alga-Derived Substrates Select for Distinct Betaproteobacterial Lineages and Contribute to Niche Separation in Limnohabitans Strains". Applied and Environmental Microbiology 77, nr 20 (26.08.2011): 7307–15. http://dx.doi.org/10.1128/aem.05107-11.
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ABSTRACTWe examined the proportions of major Betaproteobacteria subgroups within bacterial communities in diverse nonaxenic, monospecific cultures of algae or cyanobacteria: four species of cryptophyta (generaCryptomonasandRhodomonas), four species of chlorophyta (generaPediastrum,Staurastrum, andChlamydomonas), and two species of cyanobacteria (generaDolichospermumandAphanizomenon). In the cryptophyta cultures,Betaproteobacteriarepresented 48 to 71% of total bacteria, the genusLimnohabitansrepresented 18 to 26%, and thePolynucleobacterB subcluster represented 5 to 16%. In the taxonomically diverse chlorophyta group, the genusLimnohabitansaccounted for 7 to 45% of total bacteria. In contrast, cyanobacterial cultures contained significantly lower proportions of theLimnohabitansbacteria (1 to 3% of the total) than the cryptophyta and chlorophyta cultures. Notably, largely absent in all of the cultures wasPolynucleobacter necessarius(PolynucleobacterC subcluster). Subsequently, we examined the growth ofLimnohabitansstrains in the presence of different algae or their extracellular products (EPP). Two strains, affiliated withLimnohabitansplanktonicusandLimnohabitansparvus, were separately inoculated into axenic cultures of three algal species growing in an inorganic medium:Cryptomonassp.,Chlamydomonas noctigama, andPediastrum boryanum. TheLimnohabitansstrains cocultured with these algae or inoculated into their EPP consistently showed (i) pronounced population growth compared to the control without the algae or EPP and (ii) stronger growth stimulation ofL. planktonicusthan ofL. parvus.Overall, growth responses of theLimnohabitansstrains cultured with algae were highly species specific, which suggests a pronounced niche separation between two closely relatedLimnohabitansspecies likely mediated by different abilities to utilize the substrates produced by different algal species.
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Borysova, O. V. "Algal cultures as a model object of studding algal-bacterial communities (consortia)". Algologia 32, nr 2 (czerwiec 2022): 167–83. http://dx.doi.org/10.15407/alg32.02.167.
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An information on the results of the microbiological analysis of xenic cultures of green (<i>Chlorophyta</i>) and charophytes (<i>Charophyta</i>) algae is given. Algal xenic cultures are regarded as communities (consortia) of heterogeneous organisms connected with each other by trophic and topic interactions and composed of a center nucleus (autotrophic algae of one species) and consorts (several species of heterotrophic bacteria). Twelve algal xenic cultures of freshwater (<i>Сhlorella vulgaris</i> Beij., <i>Coelastrum</i> <i>rugosum</i> (P.G. Richt.,<i> Tetradesmus dimorphus</i> (Turpin) M.J.Wynne) and aerophitic (<i>Klebsormidium flaccidum</i> (Kütz.) Silva, Mattox et Blackwell) algae from the collection of M.G. Kholodny Institute of Botany NAS of Ukraine were used in investigations. Each species was represented by three strains isolated in 1961–2018 years from the territories of Ukraine and other countries of Eurasia. Overall, 82 bacterial strains were isolated and identified according to some phenotypic (morphological, chemotaxonomic, physiological and chemical) features. The study revealed complexes of four types which consisted 7 species of bacterial consorts. A qualitative composition of complexes was the same in cultures (strains) of one certain algal species but strictly different in cultures of another algal species. Although, some bacterial species were found in several complexes of different type. It is evident a tight association the heterotrophic bacterial consorts with the autotrophic determinant of consortia and conforms the consortium character of algal-bacterial communities in general. It was proposed an express method based on the use of a numerical system for morphological evaluation of bacterial colonies in preliminary study peculiarities, features and functions of consortia.
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Mayali, Xavier, Peter J. S. Franks i Farooq Azam. "Cultivation and Ecosystem Role of a Marine Roseobacter Clade-Affiliated Cluster Bacterium". Applied and Environmental Microbiology 74, nr 9 (7.03.2008): 2595–603. http://dx.doi.org/10.1128/aem.02191-07.
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ABSTRACT Isolation and cultivation are a crucial step in elucidating the physiology, biogeochemistry, and ecosystem role of microorganisms. Many abundant marine bacteria, including the widespread Roseobacter clade-affiliated (RCA) cluster group, have not been cultured with traditional methods. Using novel techniques of cocultivation with algal cultures, we have accomplished successful isolation and propagation of a strain of the RCA cluster. Our experiments revealed that, in addition to growing on alga-excreted organic matter, additions of washed bacterial cells led to significant biomass decrease of dinoflagellate cultures as measured by in vivo fluorescence. Bacterial filtrate did not adversely affect the algal cultures, suggesting attachment-mediated activity. Using an RCA cluster-specific rRNA probe, we documented increasing attachment of these algicidal bacteria during a dinoflagellate bloom, with a maximum of 70% of the algal cells colonized just prior to bloom termination. Cross-correlation analyses between algal abundances and RCA bacterial colonization were statistically significant, in agreement with predator-prey models suggesting that RCA cluster bacteria caused algal bloom decline. Further investigation of molecular databases revealed that RCA cluster bacteria were numerically abundant during algal blooms sampled worldwide. Our findings suggest that the widespread RCA cluster bacteria may exert significant control over phytoplankton biomass and community structure in the oceans. We also suggest that coculture with phytoplankton may be a useful strategy to isolate and successfully grow previously uncultured but ecologically abundant marine heterotrophs.
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Persson, Per-Edvin. "Odorous Algal Cultures in Culture Collections". Water Science and Technology 20, nr 8-9 (1.08.1988): 211–13. http://dx.doi.org/10.2166/wst.1988.0245.
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The IAWPRC Specialist Group on Tastes and Odours collected a list of odorous algal cultures available from culture collections around the world. A list of 42 algal strains is presented, supplemented by data on their odour, purity and where to obtain them.
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Abdel-Hamid, Mohammad I. "Development and application of a simple procedure for toxicity testing using immobilized algae". Water Science and Technology 33, nr 6 (1.03.1996): 129–38. http://dx.doi.org/10.2166/wst.1996.0089.
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A simple microplate technique was adopted for toxicity assessment of a number of pesticides including six herbicides (Atrazine, Dichloroprop, Glyphosphate, Chlorsulfuron, MCPA, and Simazine), an insecticide (Dimethoate) and a fungicide (Propiconazol). Growth response of free and immobilized cultures of the green chlorococcal algae Selenastrum capricornumtum to different treatments of these pesticides was tested and compared. The biotests were carried out under conditions optimal for the growth of the test alga. Algal growth was exposed in terms of dry weight, and was employed as the toxicity-response parameter. Dose-response curves were used to calculate the toxicity of the tested compounds in terms of EC50. Based on EC50 values, the responses of both immobilized and free cultures were quite similar for almost all the treatments. The technique facilitated the visual detection of the lowest toxic concentration giving no detectable algal growth (EC100). The technique is quite simple, rapid, practical, accurate, and space saving. It suggested that batteries of immobilized algae could replace free cultures in studies of toxicity testing.
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Fisher, Carolyn L., Michelle V. Fong, Pamela D. Lane, Skylar Carlson i Todd W. Lane. "Storage and Algal Association of Bacteria That Protect Microchloropsis salina from Grazing by Brachionus plicatilis". Microorganisms 11, nr 3 (18.03.2023): 786. http://dx.doi.org/10.3390/microorganisms11030786.
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Loss of algal production from the crashes of algal mass cultivation systems represents a significant barrier to the economic production of microalgal-based biofuels. Current strategies for crash prevention can be too costly to apply broadly as prophylaxis. Bacteria are ubiquitous in microalgal mass production cultures, however few studies investigate their role and possible significance in this particular environment. Previously, we demonstrated the success of selected protective bacterial communities to save Microchloropsis salina cultures from grazing by the rotifer Brachionus plicatilis. In the current study, these protective bacterial communities were further characterized by fractionation into rotifer-associated, algal-associated, and free-floating bacterial fractions. Small subunit ribosomal RNA amplicon sequencing was used to identify the bacterial genera present in each of the fractions. Here, we show that Marinobacter, Ruegeria, and Boseongicola in algae and rotifer fractions from rotifer-infected cultures likely play key roles in protecting algae from rotifers. Several other identified taxa likely play lesser roles in protective capability. The identification of bacterial community members demonstrating protective qualities will allow for the rational design of microbial communities grown in stable co-cultures with algal production strains in mass cultivation systems. Such a system would reduce the frequency of culture crashes and represent an essentially zero-cost form of algal crop protection.
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Petkov, Georgi D., i Svetlana G. Bratkova. "Viscosity of algal cultures and estimation of turbulency in devices for the mass culture of micro algae". Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 81 (18.09.1996): 99–104. http://dx.doi.org/10.1127/algol_stud/81/1996/99.
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Reese, Kristen L., Carolyn L. Fisher, Pamela D. Lane, James D. Jaryenneh, A. Daniel Jones, Matthias Frank i Todd W. Lane. "Abiotic and Biotic Damage of Microalgae Generate Different Volatile Organic Compounds (VOCs) for Early Diagnosis of Algal Cultures for Biofuel Production". Metabolites 11, nr 10 (15.10.2021): 707. http://dx.doi.org/10.3390/metabo11100707.
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Open microalgal ponds used in industrial biomass production are susceptible to a number of biotic and abiotic environmental stressors (e.g., grazers, pathogens, pH, temperature, etc.) resulting in pond crashes with high economic costs. Identification of signature chemicals to aid in rapid, non-invasive, and accurate identification of the stressors would facilitate targeted and effective treatment to save the algal crop from a catastrophic crash. Specifically, we were interested in identifying volatile organic compounds (VOCs) that can be used to as an early diagnostic for algal crop damage. Cultures of Microchloropsis gaditana were subjected to two forms of algal crop damage: (1) active grazing by the marine rotifer, Brachionus plicatilis, or (2) repeated freeze–thaw cycles. VOCs emitted above the headspace of these algal cultures were collected using fieldable solid phase microextraction (SPME) fibers. An untargeted analysis and identification of VOCs was conducted using gas chromatography-mass spectrometry (GC-MS). Diagnostic VOCs unique to each algal crop damage mechanism were identified. Active rotifer grazing of M. gaditana was characterized by the appearance of carotenoid degradation products, including β-cyclocitral and various alkenes. Freeze–thaw algae produced a different set of VOCs, including palmitoleic acid. Both rotifer grazing and freeze–thawed algae produced β-ionone as a VOC, possibly suggesting a common stress-induced cellular mechanism. Importantly, these identified VOCs were all absent from healthy algal cultures of M. gaditana. Early detection of biotic or abiotic environmental stressors will facilitate early diagnosis and application of targeted treatments to prevent algal pond crashes. Thus, our work further supports the use of VOCs for monitoring the health of algal ponds to ultimately enhance algal crop yields for production of biofuel.
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Soma, Yuko, Takashi Imaizumi, Kei-ichi Yagi i Sei-ichi Kasuga. "Estimation of Algal Succession in Lake Water Using HPLC Analysis of Pigments". Canadian Journal of Fisheries and Aquatic Sciences 50, nr 6 (1.06.1993): 1142–46. http://dx.doi.org/10.1139/f93-130.
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Seasonal variation in algal biomass in lake water was estimated using HPLC analysis of pigments. Carotenoids/chlorophyll a ratios were determined for cultures of Anabena, Microcystis, green algae, diatoms, and Cryptomonas. The contributions of various algal taxa to the total chlorophyll a content of lake water were calculated using the average carotenoid/chlorophyll a ratios of fingerprint pigments. The pigment analysis reflected the observed trend in the numbers of algae in lake water and proved to be a useful supplementary approach to evaluate algal biomass.
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Hupp, Bettina, Bernadett Pap, Attila Farkas i Gergely Maróti. "Development of a Microalgae-Based Continuous Starch-to-Hydrogen Conversion Approach". Fermentation 8, nr 7 (23.06.2022): 294. http://dx.doi.org/10.3390/fermentation8070294.
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Eukaryotic algae represent a highly heterogeneous group in terms of organization, lifestyle, and metabolic capabilities. Unicellular green microalgae are capable of biohydrogen production through direct and indirect photolysis as well as dark fermentation. Most algae hydrogen studies focus on axenic algal cultures, although these are difficult and expensive to maintain for continuous operation. Moreover, the complex interplays and metabolic fluxes between algae and bacteria in natural ecosystems provide a number of clear biological and technological benefits to large-scale functional algae-based systems. Two green algae species from the Chlamydomonas and Chlorella genera were used to engineer stable synthetic communities by incorporating a starch-degrading bacterium from the Bacillus genus into the inter-kingdom consortium. Continuous photoheterotrophic biohydrogen production was achieved by elaborating an appropriate algal–bacterial ratio and fine-tuning the culture conditions for the synthetic consortia. Medium with starch as only carbon source served as a simple model of cheap substrate for algal hydrogen generation. The engineered pairwise algal–bacterial associations showed increased biomass and biohydrogen yield compared to the axenic control conditions. Chlorella sp. MACC-360 produced a significantly higher amount of hydrogen when both the bacterium partner and starch were added to the media compared to the axenic algae. Continuous, elevated algal hydrogen production was achieved in media supplemented with 8 g L−1 starch as sole carbon source when carefully selected initial cell number values were used for the Chlorella sp. MACC-360–B. amlyloliquefaciens co-cultures.
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McAuley, P. J., i L. Muscatine. "The cell cycle of symbiotic Chlorella. IV. DNA content of algae slowly increases during host starvation of green hydra". Journal of Cell Science 85, nr 1 (1.09.1986): 73–84. http://dx.doi.org/10.1242/jcs.85.1.73.
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The distribution of DNA content of symbiotic Chlorella algae freshly isolated from green hydra was compared with that of cultured Chlorella of the NC64A strain, using flow cytometry. In nonlogarithmic cultures of NC64A most cells had accumulated in G1 phase, while in logarithmic cultures a peak containing cells in S phase and mitosis could be distinguished from the larger G1 peak. However, symbiotic algae showed a single broad peak in which there was no clear distinction between G1 and S phase/mitosis. When hydra were starved for a prolonged period, inhibiting host cell and algal division, the DNA content of the symbiotic algae slowly increased, and the number of daughter cells produced after a single feeding increased with the length of the preceding period of starvation. This suggests that symbiotic algae are able to cycle slowly through S phase, but unless the host is fed they cannot traverse into mitosis and complete the cell division cycle. No significant difference in cell size was found between algae producing either four or eight daughter cells after 1-day- or 22-day-starved hydra were fed, suggesting that algal cell size did not determine the number of daughter cells produced. Instead, this may be dependent upon the length of time the cell had spent in S phase prior to receiving the, as yet unknown, stimulus to enter into mitosis.
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Schade, Stefan, Emma Butler, Steve Gutsell, Geoff Hodges, John K. Colbourne i Mark R. Viant. "Improved Algal Toxicity Test System for Robust Omics-Driven Mode-of-Action Discovery in Chlamydomonas reinhardtii". Metabolites 9, nr 5 (10.05.2019): 94. http://dx.doi.org/10.3390/metabo9050094.
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Algae are key components of aquatic food chains. Consequently, they are internationally recognised test species for the environmental safety assessment of chemicals. However, existing algal toxicity test guidelines are not yet optimized to discover molecular modes of action, which require highly-replicated and carefully controlled experiments. Here, we set out to develop a robust, miniaturised and scalable Chlamydomonas reinhardtii toxicity testing approach tailored to meet these demands. We primarily investigated the benefits of synchronised cultures for molecular studies, and of exposure designs that restrict chemical volatilisation yet yield sufficient algal biomass for omics analyses. Flow cytometry and direct-infusion mass spectrometry metabolomics revealed significant and time-resolved changes in sample composition of synchronised cultures. Synchronised cultures in sealed glass vials achieved adequate growth rates at previously unachievably-high inoculation cell densities, with minimal pH drift and negligible chemical loss over 24-h exposures. Algal exposures to a volatile test compound (chlorobenzene) yielded relatively high reproducibility of metabolic phenotypes over experimental repeats. This experimental test system extends existing toxicity testing formats to allow highly-replicated, omics-driven, mode-of-action discovery.
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Ma, Feiyang, Patrice A. Salomé, Sabeeha S. Merchant i Matteo Pellegrini. "Single-cell RNA sequencing of batch Chlamydomonas cultures reveals heterogeneity in their diurnal cycle phase". Plant Cell 33, nr 4 (2.02.2021): 1042–57. http://dx.doi.org/10.1093/plcell/koab025.
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Abstract The photosynthetic unicellular alga Chlamydomonas (Chlamydomonas reinhardtii) is a versatile reference for algal biology because of its ease of culture in the laboratory. Genomic and systems biology approaches have previously described transcriptome responses to environmental changes using bulk data, thus representing the average behavior from pools of cells. Here, we apply single-cell RNA sequencing (scRNA-seq) to probe the heterogeneity of Chlamydomonas cell populations under three environments and in two genotypes differing by the presence of a cell wall. First, we determined that RNA can be extracted from single algal cells with or without a cell wall, offering the possibility to sample natural algal communities. Second, scRNA-seq successfully separated single cells into nonoverlapping cell clusters according to their growth conditions. Cells exposed to iron or nitrogen deficiency were easily distinguished despite a shared tendency to arrest photosynthesis and cell division to economize resources. Notably, these groups of cells not only recapitulated known patterns observed with bulk RNA-seq but also revealed their inherent heterogeneity. A substantial source of variation between cells originated from their endogenous diurnal phase, although cultures were grown in constant light. We exploited this result to show that circadian iron responses may be conserved from algae to land plants. We document experimentally that bulk RNA-seq data represent an average of typically hidden heterogeneity in the population.
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Li, Guiju, Huixiang Xie, Guisheng Song i Michel Gosselin. "Production of Chromophoric Dissolved Organic Matter (CDOM) in Laboratory Cultures of Arctic Sea Ice Algae". Water 11, nr 5 (1.05.2019): 926. http://dx.doi.org/10.3390/w11050926.
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Chromophoric dissolved organic matter (CDOM) is highly enriched in bottom sea ice in the Arctic during ice algal blooms, giving rise to multifaceted ecological implications in both the sea ice and the underlying seawater. We conducted laboratory culture incubations to assess the potential role of ice algae in the accumulation of CDOM in Arctic sea ice. Non-axenic monocultures of Attheya septentrionalis and Nitzschia frigida and a natural ice algal assemblage (NIAA) were grown at 4 °C in an f/2 medium under cool white fluorescent light. Culture samples were collected several days apart throughout the exponential, stationary, and senescent phases, and analyzed for CDOM absorbance, chlorophyll a, and bacterial cell abundance. The cultures displayed apparent specific growth rates of algal and bacterial cells comparable to those in the field. Accumulations of CDOM were observed in all cultures during the time-course incubations, with the senescent phase showing the largest accumulations and the highest production rates. The senescent-phase production rate for NIAA was ~40% higher than that for A. septentrionalis. The chlorophyll a-normalized CDOM production rates in the cultures are comparable to those reported for Arctic first-year sea ice. The absorption spectra of CDOM in the cultures exhibited characteristic short-ultraviolet shoulders similar to those previously identified in sea ice. This study demonstrates that ice algal-derived CDOM can account for the springtime accumulation of CDOM in Arctic sea ice.
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Al-Hasawi, Zaki M., Mohammad I. Abdel-Hamid, Adel W. Almutairi i Hussein E. Touliabah. "Response of Pseudokirchneriella subcapitata in Free and Alginate Immobilized Cells to Heavy Metals Toxicity". Molecules 25, nr 12 (19.06.2020): 2847. http://dx.doi.org/10.3390/molecules25122847.
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Effects of 12 heavy metals on growth of free and alginate-immobilized cells of the alga Pseudokirchneriella subcapitata were investigated. The tested metals ions include Al, As, Cd, Co, Cr, Cu, Hg, Se, Ni, Pb, Sr, and Zn. Toxicity values (EC50) were calculated by graphical interpolation from dose-response curves. The highest to the lowest toxic metals are in the order Cd > Co > Hg > Cu > Ni > Zn > Cr > Al > Se > As > Pb > Sr. The lowest metal concentration (mg L−1) inhibiting 50% (EC50) of algal growth of free and immobilized (values in parentheses) algal cells were, 0.018 (0.09) for Cd, 0.03 (0.06) for Co, 0.039 (0.06) for Hg, 0.048 (0.050) for Cu, 0.055 (0.3) for Ni, 0.08 (0.1) for Zn, 0.2 (0.3) for Cr, 0.75 (1.8) for Al, 1.2 (1.4) for Se, 3.0 (4.0) for As, 3.3 (5.0) for Pb, and 160 (180) for Sr. Free and immobilized cultures showed similar responses to Cu and Se. The free cells were more sensitive than the immobilized ones. Accordingly, the toxicity (EC50) of heavy metals derived only form immobilized algal cells might by questionable. The study suggests that batteries of alginate-immobilized algae can efficiently replace free algae for the bio-removal of heavy metals.
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Raabová, Lenka, i Ľubomír Kováčik. "Four aeroterrestrial algae grown at aspecial substrate of deglaciated coastal areas of Petuniabukta, Svalbard". Czech Polar Reports 3, nr 2 (1.06.2013): 157–62. http://dx.doi.org/10.5817/cpr2013-2-16.
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The bone remnants of sea mammals are frequently dispersed everywhere in coastal areas of Svalbard Archipelago represent aspecific natural habitat which is colonized by aeroterrestrial microscopic algae. Such bone habitat might be considered an analogue to stone substrates. However, bone habitats are not included in ecological studies of polar region. In the present study, thorough observations were made on some algal strains isolated to laboratory cultures. They included two green algal species Pseudodictyo-chloris multinucleata and Tetracystis pulchra, as well as two stramenopile algal species Heterococcus papillosus and Xanthonema debile. All these taxa are new additions to the Svalbard flora.
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Luxem, Katja E., Bas Vriens, Renata Behra i Lenny H. E. Winkel. "Studying selenium and sulfur volatilisation by marine algae Emiliania huxleyi and Thalassiosira oceanica in culture". Environmental Chemistry 14, nr 4 (2017): 199. http://dx.doi.org/10.1071/en16184.
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Environmental contextVolatile selenium compounds from the oceans may ultimately be an important selenium source for agricultural soils. It has been hypothesised that marine algae are responsible for volatile selenium emissions, but in laboratory experiments, we observed minimal volatile selenium production by two marine algae known to produce large amounts of volatile sulfur. Instead, we found hints that bacterial processes may be important in the production of volatile selenium in the oceans. AbstractVolatile methylated selenium compounds, especially dimethylselenide, are thought to comprise the majority of marine selenium emissions. Despite their potential importance for the global redistribution of this trace element, which is essential for human health, little is known about the algal production of volatile organic selenium compounds. Previous studies have found correlations between dissolved dimethylselenide concentrations, dimethylsulfide concentrations (the sulfur analogue of dimethylselenide) and proxies for algal activity, most notably during a bloom of the coccolithophorid Emiliania huxleyi. In culturing studies, we investigated the ability of three globally important marine algal species, E. huxleyi, Phaeocystis globosa and the diatom Thalassiosira oceanica, to produce dimethylselenide. Despite substantial uptake of selenium and the production of volatile sulfur, E. huxleyi and T. oceanica produced negligible volatile selenium (<2nM). P. globosa produced low amounts of volatile selenium (~8nM), but grew poorly in our laboratory. However, cultures of marine bacteria and mixed bacterial–algal cultures showed that substantial amounts of volatile selenium can be produced in the presence of marine bacteria. In addition, a culture of marine bacteria alone produced ~50nM volatile selenium, far more than axenic cultures of E. huxleyi when exposed to equivalent selenite concentrations. Our results hint that marine algae may be of minor importance in the direct production of volatile selenium in the oceans, and suggest that the production of these compounds in the marine biosphere may instead be controlled by bacterial activity.
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Beardall, John. "Algal Cultures and Phytoplankton Ecology". Phycologia 27, nr 1 (marzec 1988): 180–81. http://dx.doi.org/10.2216/i0031-8884-27-1-180.1.
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Matter, Bui, Jung, Seo, Kim, Lee i Oh. "Flocculation Harvesting Techniques for Microalgae: A Review". Applied Sciences 9, nr 15 (29.07.2019): 3069. http://dx.doi.org/10.3390/app9153069.
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Microalgae have been considered as one of the most promising biomass feedstocks for various industrial applications such as biofuels, animal/aquaculture feeds, food supplements, nutraceuticals, and pharmaceuticals. Several biotechnological challenges associated with algae cultivation, including the small size and negative surface charge of algal cells as well as the dilution of its cultures, need to be circumvented, which increases the cost and labor. Therefore, efficient biomass recovery or harvesting of diverse algal species represents a critical bottleneck for large-scale algal biorefinery process. Among different algae harvesting techniques (e.g., centrifugation, gravity sedimentation, screening, filtration, and air flotation), the flocculation-based processes have acquired much attention due to their promising efficiency and scalability. This review covers the basics and recent research trends of various flocculation techniques, such as auto-flocculation, bio-flocculation, chemical flocculation, particle-based flocculation, and electrochemical flocculation, and also discusses their advantages and disadvantages. The challenges and prospects for the development of eco-friendly and economical algae harvesting processes have also been outlined here.
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Lakatos, Gergely, Daniella Balogh, Attila Farkas, Vince Ördög, Péter Tamás Nagy, Tibor Bíró i Gergely Maróti. "Factors influencing algal photobiohydrogen production in algal-bacterial co-cultures". Algal Research 28 (grudzień 2017): 161–71. http://dx.doi.org/10.1016/j.algal.2017.10.024.
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Graham, Nigel J. D., Valerie E. Wardlaw, Roger Perry i Jia-Qian Jiang. "The significance of algae as trihalomethane precursors". Water Science and Technology 37, nr 2 (1.01.1998): 83–89. http://dx.doi.org/10.2166/wst.1998.0110.
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The objective of this study was to assess the relative importance of algae and algal derived organic precursors in the generation of Trihalomethane compounds (THMs). Laboratory tests have been carried out using cultures of two common algal species dominating natural reservoir populations to assess the importance of species, growth phase and biomass versus Extracellular product (ECP) in THM production. The results of the study showed that THMFP of algae cells and ECP increased with culture age. THM formation from cells was more than double that from ECPs for Asterionella formosa and Anabaena flosaquae. It is predicted that typical blooms in a reservoir of either species could produce a substantial fraction of the THM's formed during chlorination.
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Mangat, B. S., i M. L. Pelekis. "Changes in sugar nucleotide pyrophosphorylases and starch during growth in cultures of Polytoma uvella and Polytomella papillota". Canadian Journal of Botany 63, nr 5 (1.05.1985): 946–49. http://dx.doi.org/10.1139/b85-126.
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Changes in starch, UDPG pyrophosphorylase, and ADPG pyrophosphorylase were followed during growth in cultures of two heterotrophic algae, Polytoma uvella and Polytomella papillata. There was a steady increase in the activities of the two sugar nucleotide pyrophosphorylases. The enzyme activities reached a maximum before starch production levelled off. At all stages of growth, UDPG pyrophosphorylase activity was much higher than ADPG pyrophosphorylase activity, in both algal cultures. Changes in UDPG and ADPG in cultures of Polytomella papillata showed correlation with changes in UDPG and ADPG pyrophosphorylase activities. Results suggest that the two pyrophosphorylases provide some of the starch precursor molecules.
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Molina, E., J. Fernández, F. G. Acién i Y. Chisti. "Tubular photobioreactor design for algal cultures". Journal of Biotechnology 92, nr 2 (grudzień 2001): 113–31. http://dx.doi.org/10.1016/s0168-1656(01)00353-4.
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De la Hoz Siegler, H., A. Ben-Zvi, R. E. Burrell i W. C. McCaffrey. "The dynamics of heterotrophic algal cultures". Bioresource Technology 102, nr 10 (maj 2011): 5764–74. http://dx.doi.org/10.1016/j.biortech.2011.01.081.
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Al-Shaeri, Majed, Lynn Paterson, Margret Stobie, Paul Cyphus i Mark G. J. Hartl. "Trophic Transfer of Single-Walled Carbon Nanotubes at the Base of the Food Chain and Toxicological Response". Nanomaterials 12, nr 24 (7.12.2022): 4363. http://dx.doi.org/10.3390/nano12244363.
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The potential for trophic transfer of single-walled carbon nanotubes (SWCNTs) was assessed using the green algae Tetraselmis suecica and the blue mussel Mytilus edulis in a series of laboratory experiments. Swanee River Natural Organic Matter (SRNOM)-dispersed SWCNTs were introduced into growing algal cultures. Light microscopical observations, confirmed by scanning electronic microscopy (SEM) and Raman spectroscopy, showed that SWCNT agglomerates adhered to the external algal cell walls and transmission electronic microscopy (TEM) results suggested internalization. A direct effect of SWCNT exposure on the algae was a significant decrease in growth, expressed as chlorophyll a concentration and cell viability. Mussels, fed with algae in the presence of SWCNTs, led to significantly increased pseudofaeces production, indicating selective feeding. Nevertheless, histological sections of the mussel digestive gland following exposure showed evidence of SWCNT-containing algae. Furthermore, DNA damage and oxidative stress biomarker responses in the mussel haemocytes and gill tissue were significantly altered from baseline values and were consistent with previously observed responses to SWCNT exposure. In conclusion, the observed SWCNT-algal interaction demonstrated the potential for SWCNT entrance at the base of the food chain, which may facilitate their trophic transfer with potential consequences for human exposure and health.
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Dymova O.V., I. V. Novakovskaya, E. N. Patova, D. A. Postelnii i A. A. Petychov. "Effect of light and temperature regime on the content of carotenoids in cells oF Chloromonas reticulata (Goroshankin) Gobi". Biomics 12, nr 3 (2020): 359–66. http://dx.doi.org/10.31301/2221-6197.bmcs.2020-24.
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We studied the effect of light and temperature on the content of carotenoids in the cells of the green cryophilic alga Chloromonas reticulata during cultivation in laboratory conditions. We obtained the first information on the amount and composition of the carotenoids of the SYKOA Ch-054-11 strain from the collection of live cultures of algae of the Institute of Biology of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences. In the algal cells the carotenoids profile were β-carotene (precursor to astaxanthin), xanthophylls – neoxanthin and lutein, and the violaxanthin cycle pigments such as violaxanthin, antheraxanthin, zeaxanthin). At light of 500 μM/(m2s) PAR the concentration of carotenoids consisted of 63.5±6.5 μg/ml. At light of 35 μM/(m2s) PAR the carotenoid content in algal cells was lower by factor of 8-fold. The content of photosynthetic carotenoids increased slightly (up to 26.0 μg/ml) with a decrease of temperature from 20 to 10 ° C. The tendency to induce of astaxanthin synthesis at high light was observed.
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Satjarak, Anchittha, Jittra Piapukiew, Wikrom Chanthapatchot, Karnjana Ruen-Pham i Alisa S. Vangnai. "Hercide Atrazine Alters the Microbiota of the Filametous Green Alga Cladophora sp. Cultured from Thailand". Sains Malaysiana 50, nr 5 (31.05.2021): 1255–65. http://dx.doi.org/10.17576/jsm-2021-5005-06.
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The attached green alga Cladophora known to harbor microbiota that play important roles in ecosystem, is one of the most common freshwater filamentous green algae in rivers globally, including those in the northern part of Thailand. These rivers mostly run through agricultural regions where herbicides are heavily used to improve crop quality and quantity. The extensively-used herbicide atrazine persists in soil sediments through transport by surface runoff to rivers. The effect of such herbicide contamination on Cladophora microbiota in Thailand have not been investigated. To acquire this information, 16S rDNA amplicons were used to compare microbiota of Cladophora sp. cultures treated with a spectrum of atrazine concentrations. The results showed that the Cladophora microbiome included at least 106 possible Operational taxonomic units (OTUs) representing twelve bacterial phyla which are Acidobacteria, Actinobacteria, Armatimonadetes, Chloroflexi, Cyanobacteria, Deinococcus-Thermus, Epsilonbacteraeota, Nitrospirae, Patescibacteria, Planctomycetes, Proteobacteria, and WPS-2, representing both core and local algal bacteria. The presence of atrazine was also correlated with changes in richness of bacterial taxa suggesting that these algal epibiotic bacteria were differently affected by atrazine treatments.
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Wolfaardt, G. M., J. R. Lawrence, R. D. Robarts i D. E. Caldwell. "The role of interactions, sessile growth, and nutrient amendments on the degradative efficiency of a microbial consortium". Canadian Journal of Microbiology 40, nr 5 (1.05.1994): 331–40. http://dx.doi.org/10.1139/m94-055.
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A degradative microbial consortium consisting of at least nine bacterial and one algal species was isolated from soil with diclofop methyl as the sole carbon source. In continuous flow culture, the presence of the algae increased diclofop methyl degradation and removal by 36%. Batch culture experiments with 14C-labeled diclofop methyl confirmed algal involvement in the mineralization of diclofop methyl as there was no significant difference in the amount of 14CO2 evolved by the bacterial consortium with and without the algal activity when the consortium was cultivated in the dark to inhibit algal growth, while 11% more 14CO2 was produced in the light by the algal–bacterial consortium. Pure cultures isolated from the bacterial consortium could not individually mineralize diclofop methyl as the sole carbon source. However, when supplied with an additional carbon source, two strains could mineralize diclofop methyl. Addition of either the complex growth medium, or a cell-free filtrate from the algal–bacterial consortium to batch systems containing 14C-labeled diclofop methyl resulted in a significant increase in the production of 14CO2 by the bacterial consortium, suggesting co-metabolism of diclofop methyl in the presence of a labile carbon source. Removal of diclofop methyl by the bacterial consortium was increased by 36% when a larger surface to volume ratio was provided by glass beads that allowed extensive biofilm formation. The requirement for exogenous carbon sources and the inability of isolated pure cultures to degrade diclofop methyl indicated that interspecies interactions are necessary for degradation. The positive effect of sessile growth suggested that spatial organization of cells may also be important for degradation.Key words: consortium, degradation, herbicide, microbial interactions.
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Höger, Anna-Lena, Carola Griehl i Matthias Noll. "Infection with intracellular parasite Amoeboaphelidium protococcarum induces shifts in associated bacterial communities in microalgae cultures". Journal of Applied Phycology 33, nr 5 (6.09.2021): 2863–73. http://dx.doi.org/10.1007/s10811-021-02542-9.
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AbstractIn recent years microalgae products have developed increasing market demand, but sustainable industrial production is still challenged by biological stability of large-scale production plants. Yet the relationships between algal hosts, associated microbiomes, and contaminants in photobioreactors remains widely understudied. The aim of this study was to investigate the temporal development of microbiomes of four freshwater microalgae species Scenedesmus vacuolatus, Desmodesmus quadricauda, Chlorella sorokiniana, and Botryococcus braunii, in presence and absence of the zoosporic parasite Amoeboaphelidium protococcarum. To compare the effects of sterile and nonsterile culture conditions, infection experiments were performed in sterile laboratory (sterile) and simulated industrial conditions (open). Algal growth (dry weight, optical density, and nutrient consumption) was observed for 21 days, and samples of the associated microbiome were collected for bacterial 16S rRNA gene Illumina MiSeq sequencing. Infection patterns of A. protococcarum were algae species-specific, irrespectively of culture conditions. Bacterial community analysis demonstrated distinct and stable bacterial communities for each algae species, which were mostly dominated by α- and γ-Proteobacteria. Upon aphelid parasitosis, bacterial diversity increased, and community compositions diverged algae-specific over time. Moreover, bacterial functional traits shifted to detoxification, degradation, and cellulolysis once algae were infected. This study provides a first insight into the close connection between algae, associated bacterial microbiomes and appearing contaminants in photobioreactor systems.
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Muggia, Lucia, Polona Zalar, Armando Azua-Bustos, Carlos González-Silva, Martin Grube i Nina Gunde-Cimerman. "The beauty and the yeast: can the microalgae Dunaliella form a borderline lichen with Hortaea werneckii?" Symbiosis 82, nr 1-2 (27.07.2020): 123–31. http://dx.doi.org/10.1007/s13199-020-00697-6.
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AbstractLichenized fungi usually develop complex, stratified morphologies through an intricately balanced living together with their algal partners, but several species are known to form only more or less loose associations with algae. These borderline lichens are still little explored although they could inform us about early stages of lichen evolution. We studied the association of the extremely halotolerant fungus Hortaea werneckii with the alga Dunaliella atacamensis, discovered in a cave in the Atacama Desert (Chile), and with D. salina, common inhabitant of saltern brines. D. atacamensis forms small colonies, in which cells of H. werneckii can be frequently observed, while such interaction has not been observed with D. salina. As symbiotic interactions between Dunaliella and Hortaea have not been reported, we performed a series of co-cultivation experiments to inspect whether these species could interact and develop more distinct lichen-like symbiotic structures. We set up co-cultures between axenic strains of Hortaea werneckii (isolated both from Mediterranean salterns and from the Atacama cave) and isolates of D. atacamensis (from the Atacama cave) and D. salina (isolated from Mediterranean salterns). Although we used different growth media and cultivation approaches, bright field and SEM microscopy analyses did not indicate any mutual effects in these experiments. We discuss the implications for fungal algal interactions along the transition from algal exploiters to lichen symbioses.
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Borysova, O. V. "Algal Cultures As a Model Object of Studding Algal-Bacterial Communities (Consortia)". International Journal on Algae 24, nr 3 (2022): 237–50. http://dx.doi.org/10.1615/interjalgae.v24.i3.30.
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Park, Jason B. K., Rupert J. Craggs i Andy N. Shilton. "Algal recycling enhances algal productivity and settleability in Pediastrum boryanum pure cultures". Water Research 87 (grudzień 2015): 97–104. http://dx.doi.org/10.1016/j.watres.2015.09.013.
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Moudříková, Šárka, Ivan Nedyalkov Ivanov, Milada Vítová, Ladislav Nedbal, Vilém Zachleder, Peter Mojzeš i Kateřina Bišová. "Comparing Biochemical and Raman Microscopy Analyses of Starch, Lipids, Polyphosphate, and Guanine Pools during the Cell Cycle of Desmodesmus quadricauda". Cells 10, nr 1 (3.01.2021): 62. http://dx.doi.org/10.3390/cells10010062.
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Photosynthetic energy conversion and the resulting photoautotrophic growth of green algae can only occur in daylight, but DNA replication, nuclear and cellular divisions occur often during the night. With such a light/dark regime, an algal culture becomes synchronized. In this study, using synchronized cultures of the green alga Desmodesmus quadricauda, the dynamics of starch, lipid, polyphosphate, and guanine pools were investigated during the cell cycle by two independent methodologies; conventional biochemical analyzes of cell suspensions and confocal Raman microscopy of single algal cells. Raman microscopy reports not only on mean concentrations, but also on the distribution of pools within cells. This is more sensitive in detecting lipids than biochemical analysis, but both methods—as well as conventional fluorescence microscopy—were comparable in detecting polyphosphates. Discrepancies in the detection of starch by Raman microscopy are discussed. The power of Raman microscopy was proven to be particularly valuable in the detection of guanine, which was traceable by its unique vibrational signature. Guanine microcrystals occurred specifically at around the time of DNA replication and prior to nuclear division. Interestingly, guanine crystals co-localized with polyphosphates in the vicinity of nuclei around the time of nuclear division.
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Lawrence, Janice E., Corina P. D. Brussaard i Curtis A. Suttle. "Virus-Specific Responses of Heterosigma akashiwo to Infection". Applied and Environmental Microbiology 72, nr 12 (13.10.2006): 7829–34. http://dx.doi.org/10.1128/aem.01207-06.
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ABSTRACT We used flow cytometry to examine the process of cell death in the bloom-forming alga Heterosigma akashiwo during infection by a double-stranded DNA virus (OIs1) and a single-stranded RNA virus (H. akashiwo RNA virus [HaRNAV]). These viruses were isolated from the same geographic area and infect the same strain of H. akashiwo. By use of the live/dead stains fluorescein diacetate and SYTOX green as indicators of cellular physiology, cells infected with OIs1 showed signs of infection earlier than HaRNAV-infected cultures (6 to 17 h versus 23 to 29 h). Intracellular esterase activity was lost prior to increased membrane permeability during infection with OIs1, while the opposite was seen with HaRNAV-infected cultures. In addition, OIs1-infected cells accumulated in the cultures while HaRNAV-infected cells rapidly disintegrated. Progeny OIs1 viruses consisted of large and small morphotypes with estimated latent periods of 11 and 17 h, respectively, and about 1,100 and 16,000 viruses produced per cell, respectively. In contrast, HaRNAV produced about 21,000 viruses per cell and had a latent period of 29 h. This study reveals that the characteristics of viral infection in algae are virus dependent and therefore are variable among viruses infecting the same species. This is an important consideration for ecosystem modeling exercises; calculations based on in situ measurements of algal physiology must be sensitive to the diverse responses of algae to viral infection.
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Zachleder, Vilém, Veronika Kselíková, Ivan N. Ivanov, Vitali Bialevich, Milada Vítová, Shuhei Ota, Tsuyoshi Takeshita, Shigeyuki Kawano i Kateřina Bišová. "Supra-Optimal Temperature: An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri". Cells 10, nr 7 (16.07.2021): 1806. http://dx.doi.org/10.3390/cells10071806.
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Green algae are fast-growing microorganisms that are considered promising for the production of starch and neutral lipids, and the chlorococcal green alga Parachlorella kessleri is a favorable model, as it can produce both starch and neutral lipids. P. kessleri commonly divides into more than two daughter cells by a specific mechanism—multiple fission. Here, we used synchronized cultures of the alga to study the effects of supra-optimal temperature. Synchronized cultures were grown at optimal (30 °C) and supra-optimal (40 °C) temperatures and incident light intensities of 110 and 500 μmol photons m−2 s−1. The time course of cell reproduction (DNA replication, cellular division), growth (total RNA, protein, cell dry matter, cell size), and synthesis of energy reserves (net starch, neutral lipid) was studied. At 40 °C, cell reproduction was arrested, but growth and accumulation of energy reserves continued; this led to the production of giant cells enriched in protein, starch, and neutral lipids. Furthermore, we examined whether the increased temperature could alleviate the effects of deuterated water on Parachlorella kessleri growth and division; results show that supra-optimal temperature can be used in algal biotechnology for the production of protein, (deuterated) starch, and neutral lipids.
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Yang, Hui, Baptiste Genot, Solange Duhamel, Ryan Kerney i John A. Burns. "Organismal and cellular interactions in vertebrate–alga symbioses". Biochemical Society Transactions 50, nr 1 (28.02.2022): 609–20. http://dx.doi.org/10.1042/bst20210153.
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Photosymbioses, intimate interactions between photosynthetic algal symbionts and heterotrophic hosts, are well known in invertebrate and protist systems. Vertebrate animals are an exception where photosynthetic microorganisms are not often considered part of the normal vertebrate microbiome, with a few exceptions in amphibian eggs. Here, we review the breadth of vertebrate diversity and explore where algae have taken hold in vertebrate fur, on vertebrate surfaces, in vertebrate tissues, and within vertebrate cells. We find that algae have myriad partnerships with vertebrate animals, from fishes to mammals, and that those symbioses range from apparent mutualisms to commensalisms to parasitisms. The exception in vertebrates, compared with other groups of eukaryotes, is that intracellular mutualisms and commensalisms with algae or other microbes are notably rare. We currently have no clear cell-in-cell (endosymbiotic) examples of a trophic mutualism in any vertebrate, while there is a broad diversity of such interactions in invertebrate animals and protists. This functional divergence in vertebrate symbioses may be related to vertebrate physiology or a byproduct of our adaptive immune system. Overall, we see that diverse algae are part of the vertebrate microbiome, broadly, with numerous symbiotic interactions occurring across all vertebrate and many algal clades. These interactions are being studied for their ecological, organismal, and cellular implications. This synthesis of vertebrate–algal associations may prove useful for the development of novel therapeutics: pairing algae with medical devices, tissue cultures, and artificial ecto- and endosymbioses.
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Ren, Lingxiao, Jing Huang, Keqiang Ding, Yi Wang, Yangyang Yang, Lijuan Zhang i Haoyu Wu. "Comparative Study of Algal Responses and Adaptation Capability to Ultraviolet Radiation with Different Nutrient Regimes". International Journal of Environmental Research and Public Health 19, nr 9 (30.04.2022): 5485. http://dx.doi.org/10.3390/ijerph19095485.
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Frequent outbreaks of harmful algal blooms (HABs) represent one of the most serious outcomes of eutrophication, and light radiation plays a critical role in the succession of species. Therefore, a better understanding of the impact of light radiation is essential for mitigating HABs. In this study, Chlorella pyrenoidosa and non-toxic and toxic Microcystis aeruginosa were mono-cultured and co-cultured to explore algal responses under different nutrient regimes. Comparisons were made according to photosynthetically active radiation (PAR), UV-B radiation exerted oxidative stresses, and negative effects on the photosynthesis and growth of three species under normal growth conditions, and algal adaptive responses included extracellular polymeric substance (EPS) production, the regulation of superoxide dismutase (SOD) activity, photosynthetic pigments synthesis, etc. Three species had strain-specific responses to UV-B radiation and toxic M. aeruginosa was more tolerant and showed a higher adaptation capability to UV-B in the mono-cultures, including the lower sensitivity and better self-repair efficiency. In addition to stable μmax in PAR ad UV-B treatments, higher EPS production and enhanced production of photosynthetic pigments under UV-B radiation, toxic M. aeruginosa showed a better recovery of its photosynthetic efficiency. Nutrient enrichment alleviated the negative effects of UV-B radiation on three species, and the growth of toxic M. aeruginosa was comparable between PAR and UV-B treatment. In the co-cultures with nutrient enrichment, M. aeruginosa gradually outcompeted C. pyrenoidosa in the PAR treatment and UV-B treatment enhanced the growth advantages of M. aeruginosa, when toxic M. aeruginosa showed a greater competitiveness. Overall, our study indicated the adaptation of typical algal species to ambient UV-B radiation and the stronger competitive ability of toxic M. aeruginosa in the UV-radiated waters with severer eutrophication.
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Perković, Lucija, Elvis Djedović, Tamara Vujović, Marija Baković, Tina Paradžik i Rozelindra Čož-Rakovac. "Biotechnological Enhancement of Probiotics through Co-Cultivation with Algae: Future or a Trend?" Marine Drugs 20, nr 2 (15.02.2022): 142. http://dx.doi.org/10.3390/md20020142.
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The diversity of algal species is a rich source of many different bioactive metabolites. The compounds extracted from algal biomass have various beneficial effects on health. Recently, co-culture systems between microalgae and bacteria have emerged as an interesting solution that can reduce the high contamination risk associated with axenic cultures and, consequently, increase biomass yield and synthesis of active compounds. Probiotic microorganisms also have numerous positive effects on various aspects of health and represent potent co-culture partners. Most studies consider algae as prebiotics that serve as enhancers of probiotics performance. However, the extreme diversity of algal organisms and their ability to produce a plethora of metabolites are leading to new experimental designs in which these organisms are cultivated together to derive maximum benefit from their synergistic interactions. The future success of these studies depends on the precise experimental design of these complex systems. In the last decade, the development of high-throughput approaches has enabled a deeper understanding of global changes in response to interspecies interactions. Several studies have shown that the addition of algae, along with probiotics, can influence the microbiota, and improve gut health and overall yield in fish, shrimp, and mussels aquaculture. In the future, such findings can be further explored and implemented for use as dietary supplements for humans.
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Cimoli, Emiliano, Arko Lucieer, Klaus M. Meiners, Lars Chresten Lund-Hansen, Fraser Kennedy, Andrew Martin, Andrew McMinn i Vanessa Lucieer. "Towards improved estimates of sea-ice algal biomass: experimental assessment of hyperspectral imaging cameras for under-ice studies". Annals of Glaciology 58, nr 75pt1 (9.05.2017): 68–77. http://dx.doi.org/10.1017/aog.2017.6.
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ABSTRACTIce algae are a key component in polar marine food webs and have an active role in large-scale biogeochemical cycles. They remain extremely under-sampled due to the coarse nature of traditional point sampling methods compounded by the general logistical limitations of surveying in polar regions. This study provides a first assessment of hyperspectral imaging as an under-ice remote-sensing method to capture sea-ice algae biomass spatial variability at the ice/water interface. Ice-algal cultures were inoculated in a unique inverted sea-ice simulation tank at increasing concentrations over designated cylinder enclosures and sparsely across the ice/water interface. Hyperspectral images of the sea ice were acquired with a pushbroom sensor attaining 0.9 mm square pixel spatial resolution for three different spectral resolutions (1.7, 3.4, 6.7 nm). Image analysis revealed biomass distribution matching the inoculated chlorophyll a concentrations within each cylinder. While spectral resolutions >6 nm hindered biomass differentiation, 1.7 and 3.4 nm were able to resolve spatial variation in ice algal biomass implying a coherent sensor selection. The inverted ice tank provided a suitable sea-ice analogue platform for testing key parameters of the methodology. The results highlight the potential of hyperspectral imaging to capture sea-ice algal biomass variability at unprecedented scales in a non-invasive way.
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Maršálek, Blahoslav, i Renata Rojíčková. "Stress Factors Enhancing Production of Algal Exudates: a Potential Self-Protective Mechanism?" Zeitschrift für Naturforschung C 51, nr 9-10 (1.10.1996): 646–50. http://dx.doi.org/10.1515/znc-1996-9-1008.
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Algae are known to produce extracellular organic substances under optimum conditions and increase their production under stress. The changes in amount and composition of extracellular carbohydrates and proteins of three green algae Scenedesmus quadricauda, Chlorella kessleri and Raphidocelis subcapitata (known as Selenastrum capricornutum) were studied after a 5-days’ cultivation under the influence of different types of stress factors (osmotic, organic, and heavy metal stressors). NaCl enhanced the quantity of carbohydrates more than proteins. A higher increase of proteins than carbohydrates was observed after addition of 3,5-dichlorophenol, glyphosate and cadmium chloride to algal cultures. The production of dissolved organic matter differs from species to species, with the age of a culture and the type of stressor
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Maselli, Maira, Andreas Altenburger, Diane K. Stoecker i Per Juel Hansen. "Ecophysiological traits of mixotrophic Strombidium spp". Journal of Plankton Research 42, nr 5 (wrzesień 2020): 485–96. http://dx.doi.org/10.1093/plankt/fbaa041.
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Abstract Ciliates represent an important trophic link between nanoplankton and mesoplankton. Many species acquire functional chloroplasts from photosynthetic prey, being thus mixotrophs. Little is known about which algae they exploit, and of the relevance of inorganic carbon assimilation to their metabolism. To get insights into these aspects, laboratory cultures of three mixotrophic Strombidium spp. were established and 35 photosynthetic algal species were tested as prey. The relative contributions of ingestion and photosynthesis to total carbon uptake were determined, and responses to prey starvation were studied. Ciliate growth was supported by algal species in the 2–12 μm size range, with cryptophytes and chlorophytes being the best prey types. Inorganic carbon incorporation was only quantitatively important when prey concentration was low (3–100 μgCL−1), when it led to increased gross growth efficiencies. Chla specific inorganic carbon uptake rates were reduced by 60–90% compared to that of the photosynthetic prey. Inorganic carbon uptake alone could not sustain survival of cultures and ciliate populations declined by 25–30% during 5 days of starvation. The results suggest that mixotrophy in Strombidium spp. may substantially bolster the efficiency of trophic transfer when biomass of small primary producers is low.
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Mohshina, MM, M. Shahjahan, P. Chowdhury i MS Rahman. "Culture of Chlorella ellipsoidea in different culture media". International Journal of Agricultural Research, Innovation and Technology 7, nr 1 (25.07.2017): 51–57. http://dx.doi.org/10.3329/ijarit.v7i1.33322.
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An experiment of algal culture was conducted in natural light and temperature conditions at a balcony of a room at the 2nd floor of Fisheries Faculty Building facing the north. The experiment was done to evaluate the growth of Chlorella ellipsoidea in four different media, viz, medium I (inorganic), medium II (organic, whole pulse powder extract), medium III (organic, whole lentil powder extract) and medium IV (organic, whole gram powder extract) under natural environment conditions during January-June, 2015. Growth rates of the algal species in four different media were found not significantly different. The alga, C. ellipsoidea attained maximum cell density of 28.89×106 cell ml-1 in the 15th day in medium I, of 30.69×106 cell ml-1 in the 13th day in medium II, of 26.18×106 cell ml-1 in the 15th day in medium III and of 21.12×106 cell ml-1 in the 13th day in medium IV. The ranges of air temperature, water temperature and light intensity were 21°C to 38°C, 23°C to 36°C and 2.28×103to 9.60×103 Lux respectively during the culture period. The average sunshine period was 5.87±2.82 hrs. Total alkalinity, free CO2, pH , NO3-N and PO4-P of algal culture media I, II, III and IV were 128, 540, 554 and 322 mgL-1; 32, 162, 102, 70 mgL-1; 7.4, 8, 7.9 and 7.9; 180, 36.6, 62.4 and 150 mgL-1, and 25.2, 48.2, 42.4 and 45.6 mgL-1, respectively. According to ANOVA of cell densities of cultures of C. ellipsoidea under treatments are not significantly different (F=1.441077). It is clear that differences between them are not significant i.e. mean algal cell densities are more or less same as differences between treatments are less than 20%.Int. J. Agril. Res. Innov. & Tech. 7 (1): 51-57, June, 2017
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Lívanský, Karel. "Transversal profiles of dissolved oxygen in thin-layer open outdoor algal cultures". Algological Studies/Archiv für Hydrobiologie, Supplement Volumes 105 (24.06.2002): 173–87. http://dx.doi.org/10.1127/algol_stud/105/2002/173.
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Bialevich, Vitali, Vilém Zachleder i Kateřina Bišová. "The Effect of Variable Light Source and Light Intensity on the Growth of Three Algal Species". Cells 11, nr 8 (11.04.2022): 1293. http://dx.doi.org/10.3390/cells11081293.
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Light is the essential energy source for autotrophically growing organisms, including microalgae. Both light intensity and light quality affect cell growth and biomass composition. Here we used three green algae—Chlamydomonas reinhardtii, Desmodesmus quadricauda, and Parachlorella kessleri—to study the effects of different light intensities and light spectra on their growth. Cultures were grown at three different light intensities (100, 250, and 500 µmol m−2 s−1) and three different light sources: fluorescent lamps, RGB LEDs, and white LEDs. Cultures of Desmodesmus quadricauda and Parachlorella kessleri were saturated at 250 µmol m−2 s−1, and further increasing the light intensity did not improve their growth. Chlamydomonas reinhardtii cultures did not reach saturation under the conditions used. All species usually divide into more than two daughter cells by a mechanism called multiple fission. Increasing light intensity resulted in an increase in maximum cell size and division into more daughter cells. In Parachlorella kessleri cells, the concentration of photosynthetic pigments decreased with light intensity. Different light sources had no effect on algal growth or photosynthetic pigments. The results show a species-specific response of algae to light intensity and support the use of any white light source for their cultivation without negative effects on growth.
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Wawrik, Boris, i Brian H. Harriman. "Rapid, colorimetric quantification of lipid from algal cultures". Journal of Microbiological Methods 80, nr 3 (marzec 2010): 262–66. http://dx.doi.org/10.1016/j.mimet.2010.01.016.
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Salem, Olfat, Adel Hammad, Sayed Ismail i Abd Elghany Elgendy. "Bio-treatment of wastewater using mixed algal cultures". Arab Universities Journal of Agricultural Sciences 27, nr 3 (1.09.2019): 1871–80. http://dx.doi.org/10.21608/ajs.2019.12328.1021.
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Young, Erica B., Lindsay Reed i John A. Berges. "Growth parameters and responses of green algae across a gradient of phototrophic, mixotrophic and heterotrophic conditions". PeerJ 10 (21.07.2022): e13776. http://dx.doi.org/10.7717/peerj.13776.
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Many studies have shown that algal growth is enhanced by organic carbon and algal mixotrophy is relevant for physiology and commercial cultivation. Most studies have tested only a single organic carbon concentration and report different growth parameters which hampers comparisons and improvements to algal cultivation methodology. This study compared growth of green algae Chlorella vulgaris and Chlamydomonas reinhardtii across a gradient of photoautotrophic-mixotrophic-heterotrophic culture conditions, with five acetate concentrations. Culture growth rates and biomass achieved were compared using different methods of biomass estimation. Both species grew faster and produced the most biomass when supplied with moderate acetate concentrations (1–4 g L−1), but light was required to optimize growth rates, biomass yield, cell size and cell chlorophyll content. Higher acetate concentration (10 g L−1) inhibited algal production. The choice of growth parameter and method to estimate biomass (optical density (OD), chlorophyll a fluorescence, flow cytometry, cell counts) affected apparent responses to organic carbon, but use of OD at 600, 680 or 750 nm was consistent. There were apparent trade-offs among exponential growth rate, maximum biomass, and culture time spent in exponential phase. Different cell responses over 1–10 g L−1 acetate highlight profound physiological acclimation across a gradient of mixotrophy. In both species, cell size vs cell chlorophyll relationships were more constrained in photoautotrophic and heterotrophic cultures, but under mixotrophy, and outside exponential growth phase, these relationships were more variable. This study provides insights into algal physiological responses to mixotrophy but also has practical implications for choosing parameters for monitoring commercial algal cultivation.