Soil P composition can be conveniently determined in alkaline
extracts using solution 31P nuclear magnetic resonance (NMR) spectroscopy,
but spectral assignments are based on fragmentary literature
reports of model compounds in various extraction matrices. We report
solution 31P NMR chemical shifts of model P compounds, including inorganic
phosphates, orthophosphate monoesters and diesters, phosphonates,
and organic polyphosphates, determined in a standardized soil
P extractant (0.25 M NaOH and 0.05 M EDTA). Signals from nucleic
acids (DNA –0.37 ppm, RNA 0.54 ppm) and phospholipids (phosphatidyl
choline 0.78 ppm, phosphatidyl serine 1.57 ppm, phosphatidyl ethanolamine
1.75 ppm) could be differentiated in the orthophosphate diester
region, and were identified in a sample of cultured soil bacteria. Inorganic
and organic polyphosphates could be differentiated by the presence
of a signal at –9 ppm from the a phosphate of organic polyphosphates.
Some orthophosphate diesters, notably RNA and phosphatidyl
choline, degraded rapidly to orthophosphate monoesters in NaOH-EDTA
although DNA, other phospholipids, and orthophosphate monoesters
were more stable. Changes in probe temperature had a marked
influence on signal intensities and the relative magnitude of signals
from orthophosphate monoesters and inorganic orthophosphate, and
we suggest that solution 31P NMR spectroscopy of soil extracts be
performed at 20°C.

/pdf/phosphorus-31-nuclear-magnetic-resonance-spectral-1b6ssyhvzn.pdf

Phosphorus-31 nuclear magnetic resonance spectral assignments of phosphorus compounds in soil NaOH–EDTA extracts

Microalgal and cyanobacterial cultivation: the supply of nutrients.

Chemistry and dynamics of soil organic phosphorus.

Features of cyanobacteria are introduced for non-specialists by highlighting topics in the various chapters. Aspects where much more is known now than a decade ago are pointed out, such as the importance of cyanobacterial nitrogen fixation in the oceans. This is followed by an account of the recent molecular studies most relevant for ecologists, especially topics not mentioned elsewhere in the book. Several ecological subjects of current interest are discussed, including research which seems important, but has sometimes been overlooked. Topics mentioned include sensing the environment and other organisms and signalling between cyanobacterial cells and between cyanobacteria and other organisms, and methods for studying N and P. The authors air their views on past and present matters concerning cyanobacterial taxonomy and nomenclature. Finally, comments are made on practical topics such as the use of cyanobacteria for inoculating soils, barley straw to control blooms and the likely contribution of cyanobacteria to developments in algal biotechnology during the coming decade.

Introduction to the Cyanobacteria

Enzymes in the Environment: Activity, Ecology and Applications Soil Biology and Biochemistry

Features of the colonial diatom Didymosphenia are reviewed, especially D. geminata. Although there is a long record of its occurrence in north temperate regions, mass growths have been reported much more widely in recent years. Contrary to some statements in the literature, there are also reliable older records for the southern hemisphere, though the first report of mass growth was in New Zealand in 2004. The annual cycle of morphological changes in D. geminata in northern England, and probably elsewhere, includes a winter period when motile cells are attached to the substratum followed by spring when stalks start to develop. These raise cells into the water column and provide a site for phosphatase activity. Environmental factors associated with success include absence of extreme floods, high light, pH above neutral and nutrient chemistry. D. geminata often, but not always, occurs in waters where the N:P ratio is high for much of the year, but the key factor is the ratio of organic to inorganic phosphate. D. geminata thrives where organic P is predominant and the overall P concentration is low enough for organic P to be an important P source. It is unknown whether organic N can be used. Environmental changes increasing the relative importance of organic P are likely to favour D. geminata. Likely examples are increased N:P due to atmospheric N deposition and changes in form and seasonality of P release from organic-rich soils due to climatic warming. The nutrient chemistry of deep water released from dams to rivers also needs investigation. To what extent are genetic changes occurring in response to environmental changes and are new ecotypes spreading round the world? In spite of many adverse reports about D. geminata, such as detached mats blocking water pipes, there is still doubt about the extent to which it causes problems, particularly for fish. There have been few adverse effects on migratory salmonids in Europe and North America, but at least one report of harm to a brown trout population in USA. In New Zealand, it has caused serious problems for water sports, although it remains open to question how much adverse effect it has had on fish populations. If the presence of microcystins in or associated with D. geminata, as indicated recently for two populations, proves to be widespread and at sufficiently high concentration, their possible accumulation in fish requires study. Where control is required, this could be achieved by enhancing the ratio of inorganic to organic phosphate in the water early in the growth season. Practical ways to achieve this are suggested.

/pdf/biology-of-the-freshwater-diatom-didymosphenia-a-review-1lmhjarj92.pdf

Biology of the freshwater diatom Didymosphenia : a review

The aquatic colonial stalked diatom, Didymosphenia geminata, has acquired notoriety in recent years because of huge increases in many rivers of temperate regions. However, in some streams in northern England it has probably or, in the case of the R. Coquet (Northumberland), certainly been abundant for many decades. The paper describes the nutrient environment and phosphatase activities of Didymosphenia in Stony Gill (N. Yorkshire), a fast-flowing stream draining an upland catchment with peaty soils overlying limestone. Organic phosphate formed 85% of the filtrable phosphate in the water during the study (January–August 2000), with a maximum in April. Colonies were most abundant in June, but had disappeared by August. Surface phosphomonoesterase (PMEase) and phosphodiesterase activities assayed from March to July showed low PMEase activity in early March, but otherwise both were high throughout the period and especially so in June and July. Use of BCIP-NBT staining procedure showed that PMEase activity occurred in the stalks. A more detailed study of colony structure and staining with material from the R. Coquet in June 2006 also showed marked PMEase activity, with staining localized in the upper part of the stalks and the cells remaining unstained. It is suggested that organic phosphate is hydrolyzed in the stalk and the inorganic phosphate passes to the cell via a central tube in the stalk. It seems likely that organic phosphate as a major P source is a key factor favouring the success of Didymosphenia. The possible impact of environmental changes in the catchment such as climatic warming, C loss from peat and atmospheric N deposition is discussed.

/pdf/importance-of-organic-phosphate-hydrolyzed-in-stalks-of-the-35fw6ggeka.pdf

Importance of organic phosphate hydrolyzed in stalks of the lotic diatom Didymosphenia geminata and the possible impact of atmospheric and climatic changes

The molecular identification of seven biofilm- forming cyanobacteria and the characterization of their exopolysaccharides were made and considered in terms of potential biotechnological applications. The studied strains were isolated from phototrophic biofilms taken from various Italian sites including a wastewater treatment plant, an erod- ed soil, and a brackish lagoon. The polysaccharides were characterized by use of ion exchange chromatography, circular dichroism, and cytochemical stains. All strains pro- duced exopolysaccharides with differing ratios of hydropho- bic and hydrophilic moieties depending on the species, the polysaccharide fraction (i.e., whether capsular or released), and the ambient conditions. It was shown that the anionic nature of the exopolysaccharides was due to the presence of carboxylic and sulfated groups and is likely the main char- acteristic with industrial applicability. Potential biotechno- logical applications are discussed.

Characterization of exopolysaccharides produced by seven biofilm-forming cyanobacterial strains for biotechnological applications

Ecological aspects of phosphatase activity in cyanobacteria, eukaryotic algae and bryophytes

Phosphatase activities and environmental features were characterized for 12 terrestrial and aquatic mosses in upland northern England, along with four species sampled from subarctic Sweden. Phosphomonoesterase (PMEase) and phosphodiesterase (PDEase) activities of shoot tips were measured using para -nitrophenyl phosphate ( p -NPP) and bis- p NPP. All species showed PMEase activity, but not all showed PDEase activity. The mean pH optimum was 5·0 for PMEase and 5·7 for PDEase. The kinetic parameters K m and V max were calculated from three linear transformations of the Michaelis‐Menten equation. The mean K m values of the mosses ranged between 77 and 468 µ M for PMEase and 26 and 414 µ M for PDEase. The corresponding V max values were 0·6‐205 µ µ µ mol p NP g − 1 DW h − 1 for PMEase and 1·4‐110 µ mol pNP g − − − 1 DW h − 1 for PDEase. Mosses from Sweden displayed greater K m and smaller V max values than those from England. The aquatics Fontinalis antipyretica and Rhynchostegium riparioides displayed two-phase kinetics for PMEase and PDEase, with K m and V max being dependent on substrate concentration. Staining suggested that PMEase activity was located in the cell wall of most mosses. Phosphatase assays provide a rapid method for screening environmental nutrient status and a standard procedure is recommended.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-3040.2001.00767.x

Neil Thomas William Ellwood

Papers

Biology of the freshwater diatom Didymosphenia : a review

Importance of organic phosphate hydrolyzed in stalks of the lotic diatom Didymosphenia geminata and the possible impact of atmospheric and climatic changes

Characterization of exopolysaccharides produced by seven biofilm-forming cyanobacterial strains for biotechnological applications

Ecological aspects of phosphatase activity in cyanobacteria, eukaryotic algae and bryophytes

Characterization of the phosphatase activities of mosses in relation to their environment