Euglena

Red blooms of Euglena sp. in the floodplain wetland ecosystems of Barak Valley, Assam, India, were found to be induced by high concentrations of NH3-N, NO3, Fe, Mg and to some extent, PO4, Cu and Zn in their water. The trace elements were rapidly accumulated by the bloom organisms to high levels, whereby their concentrations in the water declined, leading to a collapse of the bloom, which tended to reappear as decomposition again led to the release of the nutrients. The bloom also harboured fairly high density of certain other algae and zooplankton, thereby acting as a sub-system within the wetland ecosystem. The bloom is non-toxic and is exploited as a fish food by the fish-farmers who artificially induce a bloom for augmenting the growth of surface-feeding species of fishes.

In anticipation that improved knowledge of euglenid morphology will provide robust apomorphy-based definitions for clades, transmission and scanning electron microscopy were used to reveal novel morphological patterns associated with the euglenid pellicle. In some taxa, the number of pellicle strips around the cell periphery reduces as discrete whorls at the anterior and posterior ends of the cell. The number of whorls at either end varies between selected euglenid taxa but is invariant within a taxon. The pattern of strip reduction associated with these whorls is shown to have at least three evolutionarily linked states: exponential, pseudoexponential, and linear. Two general equations describe these states near the posterior end of euglenid cells. Exponential patterns of strip reduction near the anterior end are described by a third equation. In addition, several euglenid taxa were found to possess conspicuous pellicle pores. These pores are arranged in discrete rows that follow the articulation zones between adjacent strips. The number of strips between rows of pores varies between taxa and displays a series of consecutive character states that differ by a power of two. The patterns of pores may not only have phylogenetical and taxonomical value but may provide morphological markers for following strip maturation during cytoskeletal reproduction.

Trends in the evolution of the euglenid pellicle were described using phylogenetic methods on 18S rDNA, morphological, and combined data from 25 mostly phototrophic taxa. The tree topology from a total-evidence analysis formed a template for a synthetic tree that took into account conflicting results derived from the partitioned datasets. Pellicle character states that can only be observed with the assistance of transmission and scanning electron microscopy were phylogenetically mapped onto the synthetic tree to test a set of previously established homology statements (inferences made independently from a cladogram). The results permitted us to more confidently infer the ancestral-derived polarities of character state transformations and provided a framework for understanding the key cytoskeletal innovations associated with the evolution of phototrophic euglenids. We specifically addressed the character evolution of (1) the maximum number of pellicle strips around the cell periphery; (2) the patterns of terminating strips near the cell posterior end; (3) the substructural morphology of pellicle strips; (4) the morphology of the cell posterior tip; and (5) patterns of pellicle pores on the cell surface.

Eukaryotic microalgae are an incredibly diverse group of organisms whose sole unifying feature is their ability to photosynthesize. They are known for producing a range of potent toxins, which can build up during harmful algal blooms causing damage to ecosystems and fisheries. Genome sequencing is lagging behind in these organisms because of their genetic complexity, but transcriptome sequencing is beginning to make up for this deficit. As more sequence data becomes available, it is apparent that eukaryotic microalgae possess a range of complex natural product biosynthesis capabilities. Some of the genes concerned are responsible for the biosynthesis of known toxins, but there are many more for which we do not know the products. Bioinformatic and analytical techniques have been developed for natural product discovery in bacteria and these approaches can be used to extract information about the products synthesized by algae. Recent analyses suggest that eukaryotic microalgae produce many complex natural products that remain to be discovered.

Red blooms of Euglena sp. in the floodplain wetland ecosystems of Barak Valley, Assam, India, were found to be induced by high concentrations of NH3-N, NO3, Fe, Mg and to some extent, PO4, Cu and Zn in their water. The trace elements were rapidly accumulated by the bloom organisms to high levels, whereby their concentrations in the water declined, leading to a collapse of the bloom, which tended to reappear as decomposition again led to the release of the nutrients. The bloom also harboured fairly high density of certain other algae and zooplankton, thereby acting as a sub-system within the wetland ecosystem. The bloom is non-toxic and is exploited as a fish food by the fish-farmers who artificially induce a bloom for augmenting the growth of surface-feeding species of fishes.

The environmental and culture conditions of a potential microalgae Euglena sanguinea were optimized for maximizing the biomass productivity. It was found that the organic macronutrient from poultry litter and organic micronutrient of seaweed extract are very effective to enhance the lipid production. Complementing, these organic nutrients with commercial NPK fertilizer, boost up the lipid productivity by 30.9% in comparison with the established standard Euglena medium. The fatty acid profile of the extracted oil by GC-MS reveals its conformity with commercial diesel.

This research paper pertains to the variation in water quality with special reference to physicochemical and biological parameters in Cauvery River and its tributaries in India over a period of 1 year. The quality of water in four streams of Cauvery River in Mysore, Mandya and Chamaraja Nagar districts, where many small scale sugar, paper industries and agricultural lands are located were analyzed. Sampling was carried out from Cauvery and its tributaries which were designated as stations 1, 2, 3 & 4 (all towards down streams of Cauvery River). The river water composition is increasingly dominated by PO4, NO3 Cl at stations 3 & 4 compared to stations 1 & 2. Significant spatial variations were observed in water level, transparency, turbidity, colour, DO, BOD, NO3, NO2 and total hardness among the physico-chemical parameters at the study locations. The DO level at stations 3 & 4 was lower than 5.0 mg/L, which is the recommended minimum allowable limit for aquatic life. 30 species of p...

Optofluidic microscopy (OFM) is a novel technique for low-cost, high-resolution on-chip microscopy imaging. In this paper we report the use of the Fresnel zone plate (FZP) based projection in OFM as a cost-effective and compact means for projecting the transmission through an OFM's aperture array onto a sensor grid. We demonstrate this approach by employing a FZP (diameter = 255 microm, focal length = 800 microm) that has been patterned onto a glass slide to project the transmission from an array of apertures (diameter = 1 microm, separation = 10 microm) onto a CMOS sensor. We are able to resolve the contributions from 44 apertures on the sensor under the illumination from a HeNe laser (wavelength = 633 nm). The imaging quality of the FZP determines the effective field-of-view (related to the number of resolvable transmissions from apertures) but not the image resolution of such an OFM system--a key distinction from conventional microscope systems. We demonstrate the capability of the integrated system by flowing the protist Euglena gracilis across the aperture array microfluidically and performing OFM imaging of the samples.