The role of annual periodic behavior of water quality parameters in primary production – Chlorophyll-a estimation

Since phytoplankton is an autochthonous primary producer, it plays a vital role in driving the water quality of rivers and lakes. Therefore, in cases where measurements are lacking, its estimation is of the essence. In the present study, Morlet wavelet spectrum (periodicity) and multiple regression analyses were conducted on 15 chemical, biological and physical water quality variables sampled at 14 sites along the Hungarian section of the River Tisza and 4 sites from artificial tributary channels for 1993–2005. Results show that annual periodicity was not always to be found in the water quality parameters, at least at certain sampling sites. Periodicity was found to vary over space and time, but in general, an increase was observed in the company of higher trophic states of the river heading downstream. Based on the spatial distribution of the periodic behavior of the water quality parameters (runoff, ions, and nutrients given in so-called periodicity indices), an improved model was constructed which was capable of explaining about half (adjusted R² = 0.5) of the phytoplankton variance in the study area.     

Aquatic insects and water quality in Peñas Blancas watershed and reservoir

The aquatic insects have been used to evaluate water quality of aquatic environments. The population of aquatic insects and the water quality of the area were characterized according to the natural and human alterations present in the study site. During the monthly-survey, pH, DO, temperature, water level, DBO, PO4 and NO3 were measured. Biological indexes (abundance, species richness and the BMWP-CR) were used to evaluate the water quality. No relation between environmental and aquatic insects was detected. Temporal and spatial differences attributed to the flow events (temporal) and the presence of Pe?as Blancas reservoir (spatial). In the future, the investigations in Pe?as Blancas watershed need to be focused on determining the real influence of the flows, sediment release and the possible water quality degradation because of agriculture activities.     

A water quality analysis system to evaluate the impact of agricultural activities on N outflow in river basins in Japan

We have developed a personal-computer-based water quality analysis system for river basins. The system estimates potential N outflow by model and calculates actual N outflow from monitoring data. For the former it uses the potential load factor method to estimate annual nitrogen load from various sources and runoff potential from each area of land in a basin. For the latter it analyzes water quality monitoring data in relation to meteorological data. We used the system to analyze N outflow in basins around Lake Kasumigaura and the Yahagi River in central Honshu, Japan. The land around Lake Kasumigaura is rather flat, and about 25% is periodically flooded for rice and lotus cultivation. The land around the Yahagi River is mountainous, and much less land is flooded. In the Yahagi River basin the actual N outflow agreed closely with the potential. However, the actual N outflow in the basin around Lake Kasumigaura was much less than the potential, suggesting that a large part of the N load is denitrified in     

Isolation and characterization of brown algal polyphenols as inhibitors of α-amylase,lipase and trypsin

Extracts ofAscophyllum nodosum, Fucus serratus, F. vesiculosus andPelvetia canaliculata contain inhibitors of α-amylase, lipase and trypsin. The inhibitors were isolated and identified by¹H NMR spectroscopy as polyphenols which have apparent molecular weights in the range from 30 000 to 100 000 daltons, as determined by ultra-filtration with Amicon membranes. These polyphenols account for the whole of the inhibitory activity in crude algal extracts. The compounds inhibit α-amylase and trypsin in an apparently non-competitive manner, when preincubated with the enzymes, and the inhibition is directly proportional to the concentration of the inhibitor. Starch protects α-amylase when added to the enzyme together with the inhibitors. Under this condition the effectiveness of the inhibitors is reduced ten-fold.     

Investigating the role of potassium and urea to control fruit drop and to improve fruit quality of “Dhakki” date palm

Fruit drop is a key issue with date palm cultivars that can be addressed with a variety of methods and strategies. Foliar application of macronutrients can be more effective in inhibiting fruit drop and improving the quality of date fruits. The current study was carried out to investigate the possible role of potassium (K) and urea to reduce fruit drop and improve the fruit quality of “Dhakki” date palm. It was conducted in a complete randomised block design with seven treatments and three replications at Pakistan's Agricultural Research Institute, Dera Ismail Khan. The treatments used were: (i) Control (distilled water spray); (ii) Potassium sulphate (K₂SO₄) at 1 %; (iii) K₂SO₄ at 1 % + Urea at 2 %; (iv) K₂SO₄ at 2 %; (v) K₂SO₄ at 2 % + Urea at 2 %; (vi) K₂SO₄ at 3 % and; (vii) K₂SO₄ at 3 % + Urea at 2 %. All the concentrations were sprayed at Kimri stage of fruit development during two consecutive growing seasons. Twenty-one date palms of equal size and age were chosen for the assessments to measure percent fruit drop and other physicochemical variables, including fruit length, fruit diameter, fruit weight, pulp percentage, yield/bundle, pH, total soluble solids (TSS), K content in fruit, and all sugars (percent) of harvested date fruit. The results revealed that bunch spray of K significantly affected all the parameters during both seasons. Application of K₂SO₄ alone and in combination with urea not only effectively reduced the fruit drop but also improved fruit quality in date where, K₂SO₄ applied at 2 % combined with urea was the best concentration in reducing fruit drop, enhancing other physicochemical attributes, and improving fruit quality of “Dhakki” date palm. This study may effectively contribute to reduce the fruit drop and enhance the fruit quality by using K and urea, enabling farmers to improve the date yield and increase economic growth.     

Hydrogen metabolism of green algae: discovery and early research – a tribute to Hans Gaffron and his coworkers

The detection of hydrogen metabolism in green algae more than 60 years ago by Hans Gaffron dispelled the widely accepted dogma at that time that this feature was unique to prokaryotic organisms. Research on this unexpected aspect of algal physiology has continued until today because of its evolutionary implications and possible practical significance. This minireview focuses on the work of Gaffron and his collaborators, whose experiments provided most of the information about the mechanism of hydrogen metabolism in algae during the 35 years following its discovery. It is shown that the emergence of our present mechanistic concepts was closely linked to the changing perception of the process of photosynthetic water oxidation. Whereas the mechanism of `photoreduction,' i.e., the photoassimilation of carbon dioxide with hydrogen as the electron donor, was well understood already by Gaffron's group as being a reaction mediated by Photosystem I only, a clear concept of the mechanism of light-dependent hydrogen production has been more difficult to establish. Gaffron and his collaborators provided ample evidence, however, that `photohydrogen' evolution can be fueled by reducing equivalents derived from a photolysis of water as well as by an oxidation of internal and external organic molecules. The presently prevailing view embraces this concept of multiple pathways, but the relative contribution of each of them, and the regulatory mechanisms determining it, remain a matter of debate. This revised version was published online in August 2006 with corrections to the Cover Date.     

Relationships between pollutant discharge and water quality in the rivers from “better” to “worse” water quality

The long-term relationship between pollutant discharge and river water quality of biological/biochemical oxygen demand (BOD) in the Yamato-gawa River, Japan, has been found to be similar to perturbation or dynamic equilibrium change of alternative stable states in the ecosystem fields with a linear relationship as a usual condition. Similar relationships have been observed in short-terms for single precipitation events both in the Richmond River, Australia, and in a mountainous watershed in Japan. On the contrary, nutrient concentrations have not changed in a long-term besides nutrient discharge increases in the Richmond River. In this paper, long-term chronological relationships of annual pollutant discharges and water quality in the Brisbane River, Australia, were investigated based on pollutant discharge estimations and water quality monitoring data as a case study in the “better” water quality river. Effects of precipitation variation were taken into account in the pollutant discharge estimations by introducing precipitation variance coefficient (PVC). Total nitrogen (TN) and total phosphorus (TP) concentrations in the river were found to be improved with fluctuations in the lower Brisbane River Catchment during 1975–2012. Long-term dynamic equilibrium alterations of pollutant discharge and water quality were found for TN and TP at the first time in the Brisbane River. The investigated term was found to be divided into two phases, 1975–2001 and 2001–2012 for TN, and 1975–2007 and 2005–2012 for TP. Both pollutant discharges and pollutant concentrations in the river were smaller in Phase 2 than Phase 1. Based on the relationships in the three rivers, a hypothesis on pollutant discharge and water quality from “better” to “worse” river water environment was presented that rapid and/or excess pollutant discharge increases cause perturbation or dynamic equilibrium alterations with the basal relationships as the linear relationships.     

Use of liposomes as membrane models to evaluate the contribution of drug–membrane interactions to antioxidant properties of etodolac

Abstract

This work stresses the need to combine antioxidant assays and drug–membrane interaction studies to describe more accurately the antioxidant profile of non-steroidal anti-inflammatory drugs (NSAIDs). Different experiments performed in liposomes and aqueous solution were compared and used to evaluate the protective effect of etodolac in lipid peroxidation. Lipid peroxidation was induced by the peroxyl radical (ROO?) derived from 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydroxyl radical (HO?) generated by the Fenton reaction and was assessed by the fluorescence intensity decay of three fluorescence probes with distinct lipophilic properties – fluorescein; hexadecanoyl aminofluorescein (HDAF) and diphenylhexatriene propionic acid (DPHPA). Membrane fluidity changes due to lipid peroxidation were also evaluated by steady-state anisotropy measurements. Interactions of etodolac with lipid bilayers were evaluated by membrane zeta-potential measurements. Results indicate a drug location near the membrane surface and show that etodolac can scavenge the radicals studied but to a variable extent, depending on the assayed media and reactive species. The use of different probes and liposomes as membrane mimetic systems allowed us to conclude that membrane lipoperoxidation is not only related to the scavenging characteristics of the antioxidants, but also to their ability to interact with lipid bilayers.     

Include or exclude? A review on the role and suitability of aquatic invertebrate neozoa as indicators in biological assessment with special respect to fresh and brackish European waters

This paper reviews published knowledge on how to deal with invasive species during biological quality assessments in European river systems for water management and assessments of ecological quality required, for example, by the European Water Frame Work Directive. The papers studied included international papers and some standards for water assessment. An overview of the current state of neozoa research showed that many different topics are treated, comprising biogeography and fauna records, species replacements and effectiveness of colonisation, life cycles, competition between native and invasive species, habitat quality and pathways of migration. Additionally, some papers have been published recently on the integration of neozoa in index-based assessment systems. Although the decline or increase of alien species populations and the corresponding impacts on indigenous populations were frequently observed, the mechanisms behind the invasions often remain hypothetical. In the reviewed papers, issues such as possible reasons for coexistence, tolerances, quality of habitat or water, life history traits and introduction of diseases were rarely covered. Few neozoa are sufficiently investigated to be categorised as indicators. After discussing the advantages and disadvantages of inclusion or exclusion, inclusion of invaders in assessments of both biodiversity (all species) and human impact (only species classified in their specific tolerance) is suggested. Further research is required to (1) update and assign ecological profiles of the non-indigenous species currently and (2) assess the effects of new invaders on native communities.     

Taxonomic and nomenclatural revision of Sládeček's list of ciliates (Protozoa: Ciliophora) as indicators of water quality

A taxonomic and nomenclatural revision of Sládeek's et al. (1981) and Wegl's (1983) lists of ciliates (Protozoa: Ciliophora) as indicators of water quality has been performed. The original reference, important synonyms, and modern taxonomic literature are provided for each of the 378 taxa recognized. The results of this revision are summarized in a table which shows the correct (modern) name, author, and date of publication of each species as well as its saprobity, its saprobic valency, its indicative weight, and its saprobic index.     

Periodic signals of climatic variables and water quality in a river – eutrophic pond – wetland cascade ecosystem tracked by wavelet coherence analysis

Lakes are sensitive to changes in their environmental boundary conditions that can be indicated in the periodic behavior of water quality variables. The present work aims to assess the degree to which common annual periodic behavior is present (1994–2010) in the meteorological parameters (global radiation, air temperature, cloud cover), streamflow; and five primary nutrients (e.g. total phosphorus, nitrate-nitrogen) as possible indicators of ecosystem vulnerability in four different ecosystems using wavelet coherence analysis. The cascade system is located in the mouth of a shallow river where the water flows through a eutrophic pond then a disturbed/undisturbed macrophyte covered wetland reaching a large shallow lake. The results highlight the differing abilities of the elements of the cascade of ecosystems to follow seasonality. The changes in water quality (nutrient cycle) in the eutrophic pond most closely mirror meteorological seasonality. The vulnerability of the wetland ecosystem was expressed by its decreased capacity to follow seasonal changes due to high algae loads and additional inflows. Moreover, the wetland proved to be weak and unstable regarding phosphorus and nitrogen retention. With the successful application of wavelet coherence analysis to the “black-box” cascade system the study sets an example for the implications of the method in such combined or stand-alone natural/partially-constructed ecosystems.     

Exploration of biguanido–oxovanadium complexes as potent and selective inhibitors of protein tyrosine phosphatases

The inhibitory effects of three biguanido-oxovanadium complexes ([VO(L(1-3))(2)]·nH(2)O: HL(1) = metformin, HL(2) = phenformin, HL(3) = moroxydine) against four protein tyrosine phosphatases (PTPs) and an alkaline phosphatase (ALP) were investigated. The complexes display strong inhibition against PTP1B and TCPTP (IC(50), 80-160 nM), a bit weaker inhibition against HePTP (IC(50), 190-410 nM) and SHP-1(IC(50), 0.8-3.3 μM) and much weaker inhibition against ALP (IC(50), 17-35 μM). Complex 3 is about twofold less potent against PTP1B, TCPTP and HePTP than complexes 1 and 2, while complex 2 inhibits SHP-1 more strongly (about three to fourfold) than the other two complexes. These results suggest that the structures of the ligands slightly influence the potency and selectivity against PTPs. The complexes inhibit PTP1B and ALP with a typical competitive type.     

Comparisons among populations and individuals to evaluate pollen–pistil interaction as a mechanism of reproductive interference in Taraxacum

Reproductive interference (RI), an interspecific mating interaction that reduces the fitness of at least one of the species involved, can lead to exclusive distributions in closely related species. A hypothesis previously proposed is that RI in plants may occur by ovule usurpation, in which pistils lack interspecific incompatibility and mistakenly accept heterospecific pollen, thereby losing an opportunity for conspecific pollen fertilization. However, few comparative studies have evaluated the consistency of the inferred mechanism within and among individuals and populations. We conducted hand-pollination experiments in six populations of three native Taraxacum species that suffered from different levels of RI from an alien congener, T. officinale, and compared pollen–pistil interactions among populations. We also investigated the interactions for eight individual T. japonicum plants whose response to heterospecific pollen deposition had been previously measured. Our results revealed that pollen tubes often penetrated native ovaries following heterospecific pollination in populations suffering from strong RI, whereas they seldom did in populations suffering from marginal RI. However, the relative frequency of the pollen tube penetration was not significantly related to the strength of alien RI. Not all pistils on an individual plant showed the same pollen receptivity following heterospecific pollination; rather, some accepted and some refused the pollen tubes. The relationship between pollen tube penetration following heterospecific pollination and the strength of the alien RI was also not significant among individuals. Our present results generally support the ovule usurpation hypothesis, but suggest that other factors, such as competition for pollinator services, variation in the effects of heterospecific pollen donors, and condition of the native inflorescences, might also affect the observed RI strength.

     

Harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters – state of knowledge and research needs

Cyanobacterial blooms have increased in freshwater ecosystems worldwide in the last century, mostly resulting from eutrophication and climate change. These blooms represent serious threats to environmental and human health because of the production of harmful metabolites, called cyanotoxins. Like many countries, Egypt has been plagued with cyanobacterial blooms in most water sources, including the Nile River, irrigation canals, lakes and fishponds. However, the data about cyanotoxins produced in these blooms are limited. Only two types of cyanotoxins, microcystins and cylindrospermopsin, have been identified and characterised, mainly from Microcystis and Cylindrospermopsis blooms. The data revealed the presence of microcystins in raw and treated drinking waters at concentrations (0.05–3.8 µg l^?1), exceeding the WHO limit (1 µg l^?1) in some drinking water treatment plants. In addition, Nile tilapia Oreochromis niloticus caught from ponds containing heavy cyanobacterial blooms have accumulated considerable amounts of cyanotoxins in their edible tissues. The data presented here could be the catalyst for the establishment of a monitoring and management programme for harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters. This review also elucidates the important research gaps and possible avenues for future research on cyanobacterial blooms and cyanotoxins in Egypt.     

DEEMY – the concept of a characterization and determination system for ectomycorrhizae

 A considerable amount of data has been published on morphological and anatomical characteristics of ectomycorrhizae but these are dispersed in several, sometimes not easily available, journals. The few keys that exist are mostly based upon host tree genera. No comprehensive determination tools for non-experts are available. An information system for specific characters of ectomycorrhizae and an interactive key are now provided by DEEMY on CD-ROM. Accepted: 6 May 1997     

Host–microbe interactions as a driver of acclimation to salinity gradients in brown algal cultures

Like most eukaryotes, brown algae live in association with bacterial communities that frequently have beneficial effects on their development. Ectocarpus is a genus of small filamentous brown algae, which comprises a strain that has recently colonized freshwater, a rare transition in this lineage. We generated an inventory of bacteria in Ectocarpus cultures and examined the effect they have on acclimation to an environmental change, that is, the transition from seawater to freshwater medium. Our results demonstrate that Ectocarpus depends on bacteria for this transition: cultures that have been deprived of their associated microbiome do not survive a transfer to freshwater, but restoring their microflora also restores the capacity to acclimate to this change. Furthermore, the transition between the two culture media strongly affects the bacterial community composition. Examining a range of other closely related algal strains, we observed that the presence of two bacterial operational taxonomic units correlated significantly with an increase in low salinity tolerance of the algal culture. Despite differences in the community composition, no indications were found for functional differences in the bacterial metagenomes predicted to be associated with algae in the salinities tested, suggesting functional redundancy in the associated bacterial community. Our study provides an example of how microbial communities may impact the acclimation and physiological response of algae to different environments, and thus possibly act as facilitators of speciation. It paves the way for functional examinations of the underlying host–microbe interactions, both in controlled laboratory and natural conditions.     

Recruitment of young women to a trial of chlamydia screening – as easy as it sounds?

Background

In the United Kingdom (UK), there is an extensive market for the class 'A' drug heroin. Many heroin users spend time in prison. People addicted to heroin often require prescribed medication when attempting to cease their drug use. The most commonly used detoxification agents in UK prisons are buprenorphine, dihydrocodeine and methadone. However, national guidelines do not state a detoxification drug of choice. Indeed, there is a paucity of research evaluating the most effective treatment for opiate detoxification in prisons. This study seeks to address the paucity by evaluating routinely used interventions amongst drug using prisoners within UK prisons.

Methods/Design

The Leeds Evaluation of Efficacy of Detoxification Study (LEEDS) Prisons Pilot Study will use randomised controlled trial methodology to compare the open use of buprenorphine and dihydrocodeine for opiate detoxification, given in the context of routine care, within HMP Leeds. Prisoners who are eligible and give informed consent will be entered into the trial. The primary outcome measure will be abstinence status at five days post detoxification, as determined by a urine test. Secondary outcomes during the detoxification and then at one, three and six months post detoxification will be recorded.     

Response of Copepods to Elevated pCO2 and Environmental Copper as Co-Stressors – A Multigenerational Study

We examined the impacts of ocean acidification and copper as co-stressors on the reproduction and population level responses of the benthic copepod Tisbe battagliai across two generations. Naupliar production, growth, and cuticle elemental composition were determined for four pH values: 8.06 (control); 7.95; 7.82; 7.67, with copper addition to concentrations equivalent to those in benthic pore waters. An additive synergistic effect was observed; the decline in naupliar production was greater with added copper at decreasing pH than for decreasing pH alone. Naupliar production modelled for the two generations revealed a negative synergistic impact between ocean acidification and environmentally relevant copper concentrations. Conversely, copper addition enhanced copepod growth, with larger copepods produced at each pH compared to the impact of pH alone. Copepod digests revealed significantly reduced cuticle concentrations of sulphur, phosphorus and calcium under decreasing pH; further, copper uptake increased to toxic levels that lead to reduced naupliar production. These data suggest that ocean acidification will enhance copper bioavailability, resulting in larger, but less fecund individuals that may have an overall detrimental outcome for copepod populations.     

Aquatic fungi in relation to the physical and chemical parameters of water quality in the Augustów Canal

The objective of this study was to determine the effects of physical and chemical water quality parameters in the Augustów Canal on the abundance and taxonomic diversity of aquatic fungi. The studies were conducted in the hydrological year 2012 along the environmentally valuable area of the Augustów Canal. The mean abundance of fungi was 2 160 ± 1840 CFU ml⁻¹. The lowest abundances were observed in the uppermost part of the canal, and the highest abundances in the southern part. A total of 38 species were identified, including 13 potentially pathogenic fungi, which predominated in the central region of the canal, called the natural lake part. Redundancy analysis (RDA) indicated that variation in water chemistry caused significant changes to fungal species diversity. The results showed that fungal species diversity and abundance in the canal were particularly dependent on the extent of water pollution, as indicated by chloride and sulphate(VI) ions and electrolytic conductivity. Other water quality parameters that influenced the development of aquatic fungi were organic matter and algal biomass, responsible for water eutrophication. We propose that mycoplankton be considered a sensitive biological indicator of water quality.