Search results for "CYANOBACTERIA"

Metabolic relation of cyanobacteria to aromatic compounds

2018

Cyanobacteria, also known as blue-green (micro)algae, are able to sustain many types of chemical stress because of metabolic adaptations that allow them to survive and successfully compete in a variety of ecosystems, including polluted ones. As photoautotrophic bacteria, these microorganisms synthesize aromatic amino acids, which are precursors for a large variety of substances that contain aromatic ring(s) and that are naturally formed in the cells of these organisms. Hence, the transformation of aromatic secondary metabolites by cyanobacteria is the result of the possession of a suitable “enzymatic apparatus” to carry out the biosynthesis of these compounds according to cellular requireme…

The allelopathic capacity of submerged macrophytes shapes the microalgal assemblages from a recently restored coastal wetland

2013

Abstract We have tested the efficiency of isolated and combined submerged macrophyte cultures to inhibit, through allelopathy, the natural phytoplankton growth. Both plants and microalgae come from the same wetland, a recently restored area in Albufera de Valencia Natural Park (Spain). The need to replant the area under restoration with submerged macrophytes makes this information essential for wetland management. The selection and culture of the submerged macrophytes used in that restoration (four charophytes: Chara hispida , Chara vulgaris , Chara baltica , Nitella hyalina , and one angiosperm: Myriophyllum spicatum ) provided a good opportunity to test in the laboratory the allelopathic …

Planktonic rotifer feeding in hypertrophic conditions

2014

We studied the role of rotifers as grazers in hypertrophic waters, dominated by poorly edible filamentous and colonial cyanobacteria. Population growth of Anuraeopsis fissa and Brachionus angularis, from hypertrophic lake Albufera in Valencia, was followed for 15 days in three treatments of different food size fractions: (a) 0–15 µm (lake water filtered through 15 µm nytal sieve), (b) 0–3 µm (15 µm lake water filtrate filtered through 3 µm nuclepore filter), and (c) 3–15 µm (re-suspension, in absolute filtered lake water, of the seston collected on the 3 µm filter, after passing lake water previously filtered through 15 µm). None of the species grew when fed the food size fraction of 3–15 µ…

Discovery of Ca oxalate crystals associated with fungi in moss travertines (Bryoherms, freshwater heterogeneous stromatolites)

1995

Buffered decalcification of live moss and liverwort (Hepaticae) travertines resulted in the release of a large number of organisms (bacteria, cyanobacteria, fungi, eukaryotic algae, and small animals), which constitute an “organic mat”; (also called an algal mat or biofilm). This mat is calcified and commonly has laminations, allowing moss travertines to be considered as stromatolitic structures. After decalcification of 300 samples of travertines (using dilute acetic acid), only 9 released Ca oxalate crystals in the form of needle bundles, spherulites, and tetragonal bipyramidal prisms. These crystalline forms are identical to those found in some phanerophytes and soils. Mycelian filaments…

2013

Vesicle transfer processes in eukaryotes depend on specific proteins, which mediate the selective packing of cargo molecules for subsequent release out of the cells after vesicle fusion to the plasma membrane. The protein Tvp38 is conserved in yeasts and higher eukaryotes and potentially involved in vesicle transfer processes at the Golgi membrane. Members of the so-called “SNARE-associated proteins of the Tvp38-family” have also been identified in prokaryotes and those belong to the DedA protein family. Tvp38/DedA proteins are also conserved in cyanobacteria and chloroplasts. While only a single member of this family appears to be present in chloroplasts, cyanobacterial genomes typically e…

Vipp1: a very important protein in plastids?!

2011

As a key feature in oxygenic photosynthesis, thylakoid membranes play an essential role in the physiology of plants, algae, and cyanobacteria. Despite their importance in the process of oxygenic photosynthesis, their biogenesis has remained a mystery to the present day. A decade ago, vesicle-inducing protein in plastids 1 (Vipp1) was described to be involved in thylakoid membrane formation in chloroplasts and cyanobacteria. Most follow-up studies clearly linked Vipp1 to membranes and Vipp1 interactions as well as the defects observed after Vipp1 depletion in chloroplasts and cyanobacteria indicate that Vipp1 directly binds to membranes, locally stabilizes bilayer structures, and thereby ret…

Biocatalytic transformations of chalcones by cyanobacteria – HPLC–MS study

2016

Food selection in Eucypris virens (Crustacea: Ostracoda) under experimental conditions

2007

Ostracods have long been studied by scientists because their fossil remnants provide a valuable tool for the reconstruction of past environmental changes, including climate change and anthropogenic eutrophication. Relatively little is known about the physiology, behaviour and reproductive ecology of recent forms. We argue that filling this gap in knowledge requires stable cultures that can be used in laboratory studies. Here we provide quantitative information on the food preference of the common non-marine ostracod Eucypris virens. Using an experimental device allowing a free choice of eight food items, including both auto- and heterotrophic organisms, observations were carried out on grou…

A Fatty Acid Based Bayesian Approach for Inferring Diet in Aquatic Consumers

2015

We modified the stable isotope mixing model MixSIR to infer primary producer contributions to consumer diets based on their fatty acid composition. To parameterize the algorithm, we generated a 'consumer-resource library' of FA signatures of Daphnia fed different algal diets, using 34 feeding trials representing diverse phytoplankton lineages. This library corresponds to the resource or producer file in classic Bayesian mixing models such as MixSIR or SIAR. Because this library is based on the FA profiles of zooplankton consuming known diets, and not the FA profiles of algae directly, trophic modification of consumer lipids is directly accounted for. To test the model, we simulated hypothet…

Taxonomic investigation using DNA fingerprinting in Geitlerinema species (Oscillatoriales, Cyanobacteria)

2007

SUMMARY The taxonomic study of 14 strains of Geitlerinema amphibium (Ag. ex Gom.) Anagnostidis and Geitlerinema unigranulatum (R.N. Singh) Komarek and Azevedo, coming from several localities was undertaken. Use was made of morphological data and molecular data were obtained by means of the DNA fingerprinting technique using highly iterated palindrome (HIP1) sequences. The employed morphological characteristics were those used for species taxonomic identification belonging to the Geitlerinema genus, namely, cell dimensions, shape of the apical cell, motility, number and localization of cyanophycin granules in the cell. The two species revealed as polymorphic were discriminated only by means …