Cyanobacteria

Cyanobacteria are oxygenic organisms that play crucial roles in the cycles of carbon, nitrogen, and oxygen. They are ideal model organisms for studying photosynthesis, nitrogen fixation, and other biological processes. In addition, cyanobacteria are well recognized for their potential for a variety of biotechnological applications. This book presents a comprehensive overview of this interesting and useful group of bacteria. Chapters discuss such topics as the molecular methods applied for identifying freshwater toxigenic cyanobacteria, the diverse industrial applications of cyanobacteria, the potential of cyanobacteria in wound healing, the production of a novel hemoglobin by Synechocystis sp. PCC 6803, and the diversity, distribution, and applications of cyanobacteria in the Brazilian coastline

Fluorescence Methods for Investigation of Living Cells and Microorganisms

Fluorescence methods play a leading role in the investigation of biological objects. They are the only non-destructive methods for investigating living cells and microorganisms in vivo. Using intrinsic and artificial fluorescence methods provides deep insight into mechanisms underlying physiological and biochemical processes. This book covers a wide range of modern methods involved in experimental biology. It illustrates the use of fluorescence microscopy and spectroscopy, confocal laser scanning microscopy, flow cytometry, delayed fluorescence, pulse-amplitude-modulation fluorometry, and fluorescent dye staining protocols. This book provides an overview of practical and theoretical aspects of fluorescence methods and their successful application in the investigation of static and dynamic processes in living cells and microorganisms

Molecular support for temporal dynamics of induced anti-herbivory defenses in the brown seaweed Fucus Vesiculosus

Grazing by the isopod Idotea baltica induces chemical defenses in the brown seaweed Fucus vesiculosus. A combination of a 33 day induction experiment, feeding choice assays and functional genomic analyses was used to investigate temporal defense patterns and to correlate changes in palatability to changes in gene expression. Despite permanent grazing, seaweed palatability varied over time. Controls were significantly more consumed than grazed pieces only after 18 and 27 days of grazing. Relative to controls, 562/402 genes were up-/down-regulated in seaweed pieces that were grazed for 18 days, i.e. when defense induction was detected. Reprogramming of the regulative expression orchestra (translation, transcription), up-regulation of genes involved in lipid and carbohydrate metabolism, intracellular trafficking, defense and stress response, as well as downregulation of photosynthesis was found in grazed seaweed. These findings indicate short-term temporal variation in defenses and that modified gene expression patterns arise at the same time when grazed seaweed pieces show reduced palatability. Several genes with putative defensive functions and cellular processes potentially involved in defence, such as reallocation of resources from primary to secondary metabolism, were reveale

Successful invaders are better defended: The example of Gracilaria vermiculophylla

To evaluate the importance of anti-herbivore resistance for algal invasion success we compared resistance traits among specimens of the red macroalga Gracilaria vermiculophylla from six native populations in Korea and China and eight invasive populations in Europe and Mexico that were maintained under identical conditions in the laboratory. Herbivorous snails both from the native range (Littorina brevicula) and from the invaded range (Littorina littorea) consumed significantly less of seaweed specimens originating from non-native populations. Metabolome profiling revealed that this preference was correlated with an increased woundactivated production of deterring prostaglandins and hydroxyeicosatetraenoic acids. Thus, invasive populations of G. vermiculophylla are more strongly defended against challenge by herbivores and other biological enemies that cause local tissue or cell disruption and activate oxylipin production. Anthropogenic distribution of genotypes adapted to resist elevated feeding pressure probably contributed to the invasion success of this species

Modelling the Seasonal Growth of the Brown Seaweed Fucus Vesiculosus in the Kiel Outdoor Benthocosms

Warming and acidification of the oceans as a consequence of increasing CO2-concentrations occur globally. In mesocosm experiments, the single and combined impact of elevated seawater temperature and pCO2 (1,100 ppm) on the brown alga Fucus vesiculosus together with its ssociated community (epiphytes and mesograzers) was studied in four consecutive experiments (from April 2013 to April 2014). Based on these experiments, a numerical boxmodel simulating the seasonal growth of F. vesiculosus in the Kiel Outdoor Benthocosms (KOBs) was developed. Nitrogen and carbon cycling in the KOBs were considered and relevant physiological and ecological processes were implemented. To run simulations under present and global change scenarios (e.g. warming, ocean acidification) the model was forced with atmospheric and hydrographic data of the Kiel fjord. DIN and DIC concentration in the water and Fucus growth as carbon and nitrogen increase were explicitly modelled. For instance, the following processes were implemented: (1) Storage of carbon and nitrogen assimilates by Fucus, leading to a temporal decoupling of assimilation and growth. (2) Shading effects of epiphytes. (3) Grazing by Idotea, Gammarus and Littorina on both Fucus and epiphytes, but with species-specific rates and preferences. At present, the model is a suitable scientific tool capable of integrating our knowledge about macroalgal processes, their growth and productivity in coastal areas. It further facilitates the communication of complex knowledge to lay persons. Ultimately, the development of a predictive model, which can be coupled to a 3D-high resolution western Baltic Sea model, is anticipated. This will allow observations on the consequences of global change for the wellbeing and distribution of F. vesiculosus in the western Baltic Sea. Understanding responses of macroalgae and of the associated community is important because changing global temperatures and elevated CO2 may affect the ecological role of Fucus as primary producer, carbon sink, water purifier, and ecosystem engineer in the coastal ecosystem of the Baltic Sea

Phytoplankton response to water quality threats in Midwest reservoirs

Harmful cyanobacterial blooms and invasive species threaten water quality. These threats are expected to worsen in the future, emphasizing the need for creative management solutions and a thorough understanding of their impacts. The objective of this dissertation is to investigate the influence of light on biomass and community composition of phytoplankton with the hypothesis that light will have an impact, regardless of nutrients and grazing. We investigate a novel geoengineering approach designed to control cyanobacteria by reducing light. We demonstrate that daily application of glacial rock flour, a fine particulate that floats on the water's surface, reduces light by half and results in up to a 78 percent decrease in cyanobacterial biovolume. We also look at the accumulation of microcystin in the tissues of bluegill and largemouth bass. Microcystin is higher in bluegill, likely because they feed from lower trophic levels. It is also higher in spring and decreases throughout the year, suggesting that time of the year might be an important consideration for microcystin fish consumption advisories. We also find that invasive zebra mussels are not causing an increase in water clarity in MO reservoirs like they are in natural, northern latitude lakes. This could be because reservoir conditions are suboptimal for zebra mussels, thus preventing them from reaching high densities. Understanding how aquatic resources have responded to stressors in the past enables us to predict how they will respond to changes in the future.Includes bibliographical references

Very High Resolution (VHR) Satellite Imagery: Processing and Applications

Recently, growing interest in the use of remote sensing imagery has appeared to provide synoptic maps of water quality parameters in coastal and inner water ecosystems;, monitoring of complex land ecosystems for biodiversity conservation; precision agriculture for the management of soils, crops, and pests; urban planning; disaster monitoring, etc. However, for these maps to achieve their full potential, it is important to engage in periodic monitoring and analysis of multi-temporal changes. In this context, very high resolution (VHR) satellite-based optical, infrared, and radar imaging instruments provide reliable information to implement spatially-based conservation actions. Moreover, they enable observations of parameters of our environment at greater broader spatial and finer temporal scales than those allowed through field observation alone. In this sense, recent very high resolution satellite technologies and image processing algorithms present the opportunity to develop quantitative techniques that have the potential to improve upon traditional techniques in terms of cost, mapping fidelity, and objectivity. Typical applications include multi-temporal classification, recognition and tracking of specific patterns, multisensor data fusion, analysis of land/marine ecosystem processes and environment monitoring, etc. This book aims to collect new developments, methodologies, and applications of very high resolution satellite data for remote sensing. The works selected provide to the research community the most recent advances on all aspects of VHR satellite remote sensing

Molecular Mechanisms Regulating Chronological Aging and Cell Death in the Toxic Dinoflagellate, Karenia brevis

The toxic dinoflagellate, Karenia brevis, forms nearly annual blooms in the Gulf of Mexico that persist for many months in coastal waters, causing extensive marine animal mortalities and human health impacts. The molecular mechanisms that contribute to cell survival in high density, low growth blooms, and the mechanisms leading to often rapid bloom demise are not well understood. The studies presented in this dissertation investigate the existence and involvement of a programmed cell death-like (PCD-like) pathway in the demise of K. brevis cultures following oxidative stress and chronological aging. Firstly, to gain an understanding of the molecular processes that underlie chronological aging in this dinoflagellate, a microarray study was carried out and identified extensive transcriptomic remodeling during the transition into stationary phase indicative of a shift in the metabolic and signaling requirements for survival in a quiescent non-dividing phase. To better understand the connection between the transcriptomic context identified in the microarray study and the presence of a PCO-like pathway in K. brevis, hallmark morphological and biochemical changes (DNA fragmentation, caspase-like activity, and caspase 3-like protein expression) were used to define PCD-like morphological changes following chronological aging and oxidative stress. Targeted in silico bioinformatic mining was used to identify enzymes potentially responsible for the activities observed, as well as the substrates. Finally, K. brevis S-adenosylmethionine synthetase (KbAdoMetS), a putative caspase substrate predicted from the bioinformatics screen, was examined using MALDI-TOF MS to confirm the validity of the bioinformatics approach. Taken together, this work identified that K. brevis contains morphological changes indicative of a caspase-dependent PCD-like pathway and that KbAdoMetS is a caspase 3-like substrate. Finally, we sought to characterize the presence of metacaspases in Karenia brevis, and specifically evaluated the role of metacaspase 1 (KbMC1) during chronological aging and death in culture. Immunocytochemistry, subcellular fractionation, and western blotting results using a custom KbMC1 peptide antibody indicate that KbMC1 may be involved in PCD-like execution through its chloroplastic localization with proposed interactions with the photosynthetic machinery. This study provides the first comprehensive investigation of the molecular processes regulating chronological aging and execution of PCD-like death in a toxic dinoflagellate

An investigation into the adsorption of cyanophages to their cyanobacterial hosts

Cyanophages, viruses that infect cyanobacteria, are known to be abundant throughout the world’s oceans. They are important because of the ecological significance of their hosts which are prominent primary producers. In the natural environment cyanobacteria undergo light-dark cycles, which might be expected to exert significant effects on the way in which cyanophages reproduce. The results in this study show how light plays an important role in cyanophage adsorption to the host cell using a model system consisting of cyanophage S-PM2 and Synechococcus sp. WH7803. An initial investigation of the role of light on phage adsorption revealed a striking light-dependence. In the dark, the phage S-PM2 was virtually not capable of adsorbing to WH7803, but adsorption resumed as soon as the light was switched on. This light-dependent phage adsorption was not just limited to the phage S-PM2, four out of nine other cyanophages showed the same effect. The host photosynthetic activity and light/dark cycles were demonstrated not to influence phage adsorption. The presence of the photosynthetic reaction centre gene psbA in cyanophage genomes was not associated with the light-dependent phage adsorption. No photoreceptor was detected from the phage S-PM2 particle. A phage-resistant mutant that S-PM2 can’t adsorb to WH7803 was isolated. A putative multicopper oxidase was found to be absent from the outer membrane fraction of the mutant. This outer membrane fraction in the wild type showed a moderate phage neutralisation activity (up to ~ 30%). To test whether the putative multicopper oxidase was the S-PM2 receptor, a recombinant WH7803 strain was constructed by inactivating the putative multicopper oxidase gene. As S-PM2 can still adsorb to the knockout mutant as efficiently as to the wild type, it suggests that the multicopper oxidase is not the phage receptor and that loss of the putative multicopper oxidase is probably a pleiotropic consequence of the loss of the S-PM2 receptor or other components, such as lipopolysaccharide, that is needed for a successful S-PM2 adsorption