Search results for "algae"
showing 10 items of 403 documents
In vivo ANALYSIS OF SLOW CHLOROPHYLL FLUORESCENCE INDUCTION KINETICS IN ALGAE: PROGRESS, PROBLEMS AND PERSPECTIVES
1993
Coralline algal growth-increment widths archive North Atlantic climate variability
2011
Over the past decade coralline algae have increasingly been used as archives of paleoclimate information. Encrusting coralline algae, which deposit annual growth increments in a high Mg-calcite skeleton, are amongst the longest-lived shallow marine organisms. In fact, a live-collected plant has recently been shown to have lived for at least 850 years based on radiometric dating. While a number of investigations have successfully used geochemical information of coralline algal skeletons to reconstruct sea surface temperatures, less attention has been paid to employ growth increment widths as a temperature proxy. Here we explore the relationship between growth and environmental parameters in …
Phaenocompsopogon pustulatus n.gen.n. sp., a calcareous alga from the lacustrine rotliegend of the Saar-Nahe Basin (SW-Germany)
1992
Phaenocompsopogon pustulatus n. gen. n. sp. is a calcareous freshwater alga, probably of rhodophycean affinity. The fossils are mainly known from one locality in the Lower Permian of the Saar-Nahe Basin. The algal remains form a packstone in the Reckweilerhof-Bank of the Altenglan Formation. The simple thallus branches irregularly y-shaped and is covered with abundant pustules. An axial canal is characteristic, as are distinct cell features of an inner and outer cortex surrounding a structureless medulla. Most fossils are silicified and often three-dimensionally preserved. The algae lived in a wave-dominated environment, probably in offshore shallow water. The limited occurrence suggests sp…
The compound internal pyrenoid in cultured cells of the green algaMonoraphidium griffithii (Berkel.) Komar.-Legner.
1979
The chloroplast ultrastructure ofMonoraphidium griffithii (Berkel.) Komar.-Legner. has been studied in axenic cultures of various ages. The algae have grown in a complete nutrient solution (illumination about 3,000 lx) and on its agar medium (illumination about 600 lx). The large parietal cup-shaped chloroplast of the cells includes a multiformed compound internal pyrenoid that is situated, especially in older cells, in the central part of the chloroplast opposite to the dictyosome and the nucleus. The chloroplast thylakoids either reach the edge of the pyrenoid or penetrate its matrix and run there parallel in more or less long bits. Starch grains were not found to form any sheath around t…
Algae biomass: characteristics and applications. Towards algae-based products
2018
This book is a compendium of knowledge on the useful properties of algae in the context of application as a useful component of innovative natural products. It presents all aspects of industrial applications of macroalgae biomass derived from the natural environment. Despite many interesting characteristics, algae are still regarded as undervalued raw material, therefore, present in the following chapters are not only environmental benefits arising from the development of excessive algal biomass, but also the distribution and biology of algae in natural conditions in reservoirs, methods of obtaining extracts from biomass of algae for industrial purposes. Furthermore, it also includes topics…
Comparison of epifluorescence microscopy and flow cytometry in counting freshwater picophytoplankton
2021
The smaller the phytoplankton, the greater effort is required to distinguish individual cells by optics-based methods. Flow cytometry is widely applied in marine picophytoplankton research, but in freshwater research its role has remained minor. We compared epifluorescence microscopy and flow cytometry in assessing the composition, abundance and cell sizes of autofluorescent picophytoplankton in epilimnia of 46 Finnish lakes. Phycocyaninrich picocyanobacteria were the most dominant. The two methods yielded comparable total picophytoplankton abundances, but the determination of cell sizes, and thus total biomasses, were on average an order of magnitude higher in the microscopy results. Howev…
Technologies for cultivation and exploitation of microalgae in industrial applications
2020
This thesis work is focused on technologies for the development of the microalgal industry. During this 3-years PhD work several themes were addressed. Section 1 consists in a literature review concerning the general features of microalgae, their composition and a description of the photosynthetic process. Furthermore, themes such as biosynthetic pathways, growth kinetics, microalgae cultivation and their applications are reviewed. Section 2 focuses on the genetic manipulation of microalgae aimed at producing a vitamin B12-enriched food supplement. In this case, the human intrinsic factor gene, was inserted in the genome of the microalgae Chlamydomonas reinardhtii in order to integrate new …
Biologically active compounds in algae and their application in plant growth stimulation
2016
In recent years the bioactive substances of natural origin gained more and more interest. Among such substances, the compounds isolated from microalgae and seaweeds, mainly the polyphenols, polysaccharides, plant hormones, pigments and fatty acids, an find an application in many industries, particularly in medicine, pharmaceutics, cosmetics and agriculture. Biostimulants from seaweeds have been used and manufactured for years, giving confirmation of its effectiveness in field trials, enhancing the growth of crops giving better yields. Nowadays, the legislation processes are more difficult and intricate, so it is harder to register new products. Everyone put more attention on the answers for…
Periphyton pigment analyses using paper chromatography
1983
Paper chromatography was used to study the community structure, the proportion of degraded chlorophylls to the total pigment content, and the chlorophyll and carotenoid content of the epilithic periphyton algae from Lake Tahoe, California-Nevada. Analyses were made using both samples directly from the lake and cultured periphytic algae. The extraction was made with boiling 100% methanol; two dimensional chromatography was used to separate the pigments. The relative contribution of different pigment fractions to total light absorption by the complete periphyton extract was estimated by planimetric integration of absorption curves. From the pigment structure, estimates were made of the propor…
Carotenoids
2009
Publisher Summary This chapter provides an overview of what is known about carotenoid metabolism in Chlamydomonas with reference to other green algae and vascular plants. The biosynthesis of carotenoids and the subdivisions of carotenogenesis are described. With respect to subcellular distribution, the carotenoids in vegetative cells localize to the chloroplast where they either serve as photosynthetic pigments bound to the protein complexes of the two photosystems, or as components of the eyespot apparatus is outlined with its functional significance. Carotenoids can serve as precursors of a number of other molecules with important physiological functions in Chlamydomonas.