Macroinvertebrate community composition and diversity in ephemeral and perennial ponds on unregulated floodplain meadows in the UK

Ponds are common and abundant landscape features in temperate environments, particularly on floodplains where lateral connectivity with riverine systems persists. Despite their widespread occurrence and importance to regional diversity, research on the ecology and hydrology of temperate ephemeral and perennial floodplain ponds lags behind that of other shallow waterbodies. This study examines the aquatic macroinvertebrate diversity of 34 ponds (20 perennial and 14 ephemeral) on two unregulated riverine floodplain meadows in Leicestershire, UK. Perennial ponds supported nearly twice the diversity of ephemeral ponds. Despite frequent inundation of floodwater and connectivity with other floodplain waterbodies, ephemeral ponds supported distinct invertebrate communities when compared to perennial ponds. When the relative importance of physical, chemical, biological and spatial characteristics was examined, physical and chemical characteristics were found to account for more variation in community composition than biological or spatial variables. The results suggest that niche characteristics rather than neutral colonisation processes dominate the structure of invertebrate communities of floodplain ponds. The maintenance of pond networks with varying hydroperiod lengths and environmental characteristics should be encouraged as part of conservation management strategies to provide heterogeneous environmental conditions to support and enhance aquatic biodiversity at a landscape scale.     

Measurement of dietary exposure: a challenging problem which may be overcome thanks to metabolomics?

The diet is an important environmental exposure, and its measurement is an essential component of much health-related research. However, conventional tools for measuring dietary exposure have significant limitations being subject to an unknown degree of misreporting and dependent upon food composition tables to allow estimation of intakes of energy, nutrients and non-nutrient food constituents. In addition, such tools may be inappropriate for use with certain groups of people. As an alternative approach, the recent techniques of metabolite profiling or fingerprinting, which allows simultaneous monitoring of multiple and dynamic components of biological fluids, may provide metabolic signals indicative of food intake. Samples can be analysed through numerous analytical platforms, followed by multivariate data analysis. In humans, metabolomics has been applied successfully in pharmacology, toxicology and medical screening, but nutritional metabolomics is still in its infancy. Biomarkers of a small number of specific foods and nutrients have been developed successfully but less targeted and more high-throughput methods, that do not need prior knowledge of which signals might be discriminatory, and which may allow a more global characterisation of dietary intake, remain to be tested. A proof a principle project (the MEDE Study) is currently underway in our laboratories to test the hypothesis that high-throughput, non-targeted metabolite fingerprinting using flow injection electrospray mass spectrometry can be applied to human biofluids (blood and urine) to characterise dietary exposure in humans.     

Faunal response to benthic and hyporheic sedimentation varies with direction of vertical hydrological exchange

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Spontaneous and GABA-induced single channel currents in cultured murine spinal cord neurons

Intracellular and patch clamp recordings were made from embryonic mouse spinal cord neurons growing in primary cell culture. Outside-out membrane patches obtained from these cells usually showed spontaneous single channel currents when studied at the resting potential (-56 +/- 1.5 mV). In 18 out of 30 patches tested, spontaneous single channel activity was abolished by making Tris+ the major cation on both sides of the membrane. The remaining patches continued to display spontaneous single channel currents under these conditions. These events reversed polarity at a patch potential of 0 mV and displayed a mean single channel conductance of 24 +/- 1.2 pS. Application of the putative inhibitory transmitter gamma-aminobutyric acid (0.5-10 microM) to outside-out patches of spinal cord cell membrane induced single channel currents in 10 out of 15 patches tested. These channels had a primary conductance of 29 +/- 2.8 pS in symmetrical 145 mM Cl- solutions. Frequency distributions for the open times of these channels were well fit by the sum of a fast exponential term ("of") with a time constant tau of = 4 +/- 1.3 ms and a slow exponential term ("os") with a time constant tau os = 24 +/- 8.1 ms. Frequency distributions for channel closed times were also well fit by a double exponential equation, with time constants tau cf = 2 +/- 0.2 ms and tau cs = 62 +/- 20.9 ms.     

The impact of <Emphasis Type="Italic">MTHFR</Emphasis> 677C → T risk knowledge on changes in folate intake: findings from the Food4Me study

Background

It is hypothesised that individuals with knowledge of their genetic risk are more likely to make health-promoting dietary and lifestyle changes. The present study aims to test this hypothesis using data from the Food4Me study. This was a 6-month Internet-based randomised controlled trial conducted across seven centres in Europe where individuals received either general healthy eating advice or varying levels of personalised nutrition advice. Participants who received genotype-based personalised advice were informed whether they had the risk (CT/TT) (n?=?178) or non-risk (CC) (n?=?141) alleles of the methylenetetrahydrofolate reductase (MTHFR) gene in relation to cardiovascular health and the importance of a sufficient intake of folate. General linear model analysis was used to assess changes in folate intake between the MTHFR risk, MTHFR non-risk and control groups from baseline to month 6 of the intervention.

Results

There were no differences between the groups for age, gender or BMI. However, there was a significant difference in country distribution between the groups (p?=?0.010). Baseline folate intakes were 412?±?172, 391?±?190 and 410?±?186 μg per 10 MJ for the risk, non-risk and control groups, respectively. There were no significant differences between the three groups in terms of changes in folate intakes from baseline to month 6. Similarly, there were no changes in reported intake of food groups high in folate.

Conclusions

These results suggest that knowledge of MTHFR 677C?→?T genotype did not improve folate intake in participants with the risk variant compared with those with the non-risk variant.

Trial registration

ClinicalTrials.gov NCT01530139

     

Gene methylation parallelisms between peripheral blood cells and oral mucosa samples in relation to overweight

Epigenetics has an important role in the regulation of metabolic adaptation to environmental modifications. In this sense, the determination of epigenetic changes in non-invasive samples during the development of metabolic diseases could play an important role in the procedures in primary healthcare practice. To help translate the knowledge of epigenetics to public health practice, the present study aims to explore the parallelism of methylation levels between white blood cells and buccal samples in relation to obesity and associated disorders. Blood and buccal swap samples were collected from a subsample of the Spanish cohort of the Food4Me study. Infinium HumanMethylation450 DNA Analysis was carried out for the determination of methylation levels. Standard deviation for β values method and concordance correlation analysis were used to select those CpG which showed best parallelism between samples. A total of 277 CpGs met the criteria and were selected for an enrichment analysis and a correlation analysis with anthropometrical and clinical parameters. From those selected CpGs, four presented high associations with BMI (cg01055691 in GAP43; r = ?0.92 and rho = ?0.84 for blood; r = ?0.89 and rho = ?0.83 for buccal sample), HOMA-IR (cg00095677 in ATP2A3; r = 0.82 and rho = ?0.84 for blood; r = ?0.8 and rho = ?0.83 for buccal sample) and leptin (cg14464133 in ADARB2; r = ?0.9182 and rho = ?0.94 for blood; r = ?0.893 and rho = ?0.79 for buccal sample). These findings demonstrate the potential application of non-invasive buccal samples in the identification of surrogate epigenetic biomarkers and identify methylation sites in GAP43, ATP2A3 and ADARB2 genes as potential targets in relation to overweight management and insulin sensibility.