Age-Dependent Effects of ELF-MF on Oxidative Stress in the Brain of Mongolian Gerbils

The aim of study was to investigate the effects of extremely low frequency magnetic field (ELF-MF; 50 Hz; 0.1, 0.25 and 0.5 mT) on oxidative stress in the brain of 3- (adult) and 10-month-old (middle-aged) gerbils. Nitric oxide (NO) level, superoxide (O₂ ^?) production, superoxide dismutase (SOD) activity, and index of lipid peroxidation (ILP) were measured in the forebrain cortex, striatum, hippocampus, and cerebellum immediately and 3 days after cessation of 7-day exposure. In all gerbils, ELF-MF significantly increased oxidative stress in all tested brain regions. This effect was correlated with the value of magnetic induction and was higher in middle-aged gerbils. Three days after cessation of exposure, the values of examined parameters were closer to control levels. In adult gerbils, the effect of ELF-MF of 0.1 mT on NO level, O₂ ^? production and SOD activity was almost fully disappeared, and ILP was at the control level regardless of the value of magnetic induction. In middle-aged gerbils, the effect of ELF-MF was still present but to a lesser degree than those observed immediately after cessation of exposure. These findings pointed out the ability of ELF-MF to induce age- and magnetic induction-dependent modification of oxidative stress in the brain.     

Species traits predict assembly of mayfly and stonefly communities along pH gradients

Much recent ecological research has centred on the interrelations between species diversity and ecological processes. In the present study, I show how species traits may aid in comprehending ecology by studying the link between an environmental variable and functional traits. I examined the composition of species traits with a theoretically underpinned relationship to ecological processes along a pH gradient. I focused on body size, reproductive output, life cycle length and feeding habit of mayflies and stoneflies. In mayfly assemblages, I found smaller body size, greater reproductive output, faster life cycles and a larger proportion of gathering collectors and scrapers with increasing pH. In stonefly assemblages, I found smaller body size, greater reproductive output and faster life cycles at sites with a history of long-term natural acidification, but no clear trends in feeding habits and in most traits where acidification is anthropogenic. The results suggest that mayflies and stoneflies exhibit different ecological functions following different ecological strategies. Mayflies follow an opportunistic strategy relative to stoneflies, likely facilitating high rates of ecological processes with respect to the autotrophic resource base at neutral sites. Relative to mayflies, stoneflies follow an equilibrium strategy contributing to ecological functioning in heterotrophic ecosystems and likely maintaining heterotrophic processes despite the erosion of species diversity in response to acidification. The rules governing an ecological community may be more readily revealed by studying the distribution of species traits instead of species diversity; by studying traits, we are likely to improve our understanding of the workings of ecological communities.     

Demasculinization and feminization of male gonads by atrazine: consistent effects across vertebrate classes

Atrazine is the most commonly detected pesticide contaminant of ground water, surface water, and precipitation. Atrazine is also an endocrine disruptor that, among other effects, alters male reproductive tissues when animals are exposed during development. Here, we apply the nine so-called "Hill criteria" (Strength, Consistency, Specificity, Temporality, Biological Gradient, Plausibility, Coherence, Experiment, and Analogy) for establishing cause-effect relationships to examine the evidence for atrazine as an endocrine disruptor that demasculinizes and feminizes the gonads of male vertebrates. We present experimental evidence that the effects of atrazine on male development are consistent across all vertebrate classes examined and we present a state of the art summary of the mechanisms by which atrazine acts as an endocrine disruptor to produce these effects. Atrazine demasculinizes male gonads producing testicular lesions associated with reduced germ cell numbers in teleost fish, amphibians, reptiles, and mammals, and induces partial and/or complete feminization in fish, amphibians, and reptiles. These effects are strong (statistically significant), consistent across vertebrate classes, and specific. Reductions in androgen levels and the induction of estrogen synthesis - demonstrated in fish, amphibians, reptiles, and mammals - represent plausible and coherent mechanisms that explain these effects. Biological gradients are observed in several of the cited studies, although threshold doses and patterns vary among species. Given that the effects on the male gonads described in all of these experimental studies occurred only after atrazine exposure, temporality is also met here. Thus the case for atrazine as an endocrine disruptor that demasculinizes and feminizes male vertebrates meets all nine of the "Hill criteria".     

Correction to: Pyrethrin from Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch. Bip.): biosynthesis,biological activity,methods of extraction and determination

Phytochemistry Reviews -     

Proteome sequence features carry signatures of the environmental niche of prokaryotes

Background  

Prokaryotic environmental adaptations occur at different levels within cells to ensure the preservation of genome integrity, proper protein folding and function as well as membrane fluidity. Although specific composition and structure of cellular components suitable for the variety of extreme conditions has already been postulated, a systematic study describing such adaptations has not yet been performed. We therefore explored whether the environmental niche of a prokaryote could be deduced from the sequence of its proteome. Finally, we aimed at finding the precise differences between proteome sequences of prokaryotes from different environments.     

MEMOSys: Bioinformatics platform for genome-scale metabolic models

Background  

Recent advances in genomic sequencing have enabled the use of genome sequencing in standard biological and biotechnological research projects. The challenge is how to integrate the large amount of data in order to gain novel biological insights. One way to leverage sequence data is to use genome-scale metabolic models. We have therefore designed and implemented a bioinformatics platform which supports the development of such metabolic models.     

Current status of iodine intake in Croatia--the results of 2009 survey

In 1996, due to persistence of mild to moderate iodine deficiency, new law on obligatory salt iodination with 25 mg of potassium iodide (KI) per kg of salt was implemented in Croatia. Along with a new law, a new program for monitoring of iodine prophylaxis was implemented. Investigations of goiter and iodine intake performed in 2002, demonstrated sufficient iodine intake in Croatia with overall median of urinary iodine concentration (UIC) for schoolchildren in Croatia of 140 microg/L. In 2002, thyroid volumes (TV) measured by ultrasound in schoolchildren from all four geographic regions of Croatia were for the first time within the normal range according to ICCIDD reference values. Nowadays, Croatia is internationally recognized as iodine sufficient country. The aim of the present study was to assess current status of iodine intake in Croatia. The investigation was carried out in 2009. A total of 386 schoolchildren aged 7-10 years from all four major geographic regions of Croatia, 103 euthyroid pregnant women and 36 women of child-bearing age from Zagreb, the capital, were included in the survey. Urinary iodine concentration (UIC) was measured in all participants. Thyroid volumes were measured by ultrasound in schoolchildren from the capital of Zagreb (N = 101) and the village of Rude (N = 56). In the time period 2002-2009, the content of KI was analyzed in 384 salt samples from Croatian salt plants and samples of imported salt. An overall median UIC for schoolchildren in Croatia was 248 microg/L. Median UIC in pregnant women was 159 microg/L, with 50% of samples below and under 150 microg/L. Median UIC in women of child-bearing age was 136 microg/L. Thyroid volumes in schoolchildren were within the normal range according to the new reference values. Mean value of KI/kg of salt in samples from Croatian salt plants was 25.5 mg/kg and 24.9 mg/kg in samples of imported salt. A total of 72/384 (18.8%) of salt samples didn't corresponded to the Croatian law on obligatory salt iodination. Presented data indicate sufficient iodine intake of the Croatian population. Current medians of UIC in schoolchildren in Croatia are significantly higher than medians measured in 2002. This indicates that other potential sources of iodine are present in Croatian diet that may contribute to overall iodine intake. Due to rising medians of UIC in schoolchildren in Croatia, it is important to conduct nutrition studies to identify potential sources of "silent prophylaxis" in order to avoid iodine excess.     

Mayfly emergence along an oligotrophic Dinaric karst hydrosystem: spatial and temporal patterns,and species–environment relationship

Mayfly emergence was studied in the Plitvice Lakes National Park (Croatia) monthly over a 2-year period in four habitats (springs, streams, mountainous rivers, tufa barriers) using monthly collections of emergence traps. A total of 12 mayfly taxa were recorded. Almost half of the collected specimens belonged to the genus Baetis Leach, 1815, which was recorded at every site, but we were unable to distinguish between two included species (B. rhodani and B. cf. nubecularis). Other abundant species were Centroptilum luteolum (Müller, 1776), Alainites muticus (Linnaeus, 1758), Habrophlebia lauta Eaton 1884, Paraleptophlebia submarginata (Stephens, 1835), Serratella ignita (Poda, 1761), Ephemera danica Müller, 1764 and Rhithrogena braaschi Jacob, 1974. The mayfly assemblages at all sites were dominated by species typical of the rhithral zone, but there was a shift in species composition along a longitudinal gradient (from 720 to 390 m a.s.l.) from dominance of eucrenal–epirhithral to metarhithral–hyporhithral elements and finally to appearance of metapotamal and littoral elements. Two environmental factors, maximum water temperature and mean pH, had the highest influence on the mayfly assemblages. Emergence mainly occurred between March and November and was related to the elevated water temperature. Emergence patterns of some species were in accordance with their typical Central European emergence patterns (e.g. S. ignita, H. lauta) while some others showed certain discrepancies (e.g. longer emergence period in Rh. braaschi and P. submarginata, one generation emergence in A. muticus and variable emergence patterns between the sites and between the two studied years in C. luteolum). The current study provides a significant contribution to the knowledge of mayfly ecology in karst freshwater habitats which forms a basis for further investigation and monitoring of mayflies in this area.