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.     

Stability of Metabolic Correlations under Changing Environmental Conditions in Escherichia coli – A Systems Approach

Background

Biological systems adapt to changing environments by reorganizing their cellular and physiological program with metabolites representing one important response level. Different stresses lead to both conserved and specific responses on the metabolite level which should be reflected in the underlying metabolic network.

Methodology/Principal Findings

Starting from experimental data obtained by a GC-MS based high-throughput metabolic profiling technology we here develop an approach that: (1) extracts network representations from metabolic condition-dependent data by using pairwise correlations, (2) determines the sets of stable and condition-dependent correlations based on a combination of statistical significance and homogeneity tests, and (3) can identify metabolites related to the stress response, which goes beyond simple observations about the changes of metabolic concentrations. The approach was tested with Escherichia coli as a model organism observed under four different environmental stress conditions (cold stress, heat stress, oxidative stress, lactose diauxie) and control unperturbed conditions. By constructing the stable network component, which displays a scale free topology and small-world characteristics, we demonstrated that: (1) metabolite hubs in this reconstructed correlation networks are significantly enriched for those contained in biochemical networks such as EcoCyc, (2) particular components of the stable network are enriched for functionally related biochemical pathways, and (3) independently of the response scale, based on their importance in the reorganization of the correlation network a set of metabolites can be identified which represent hypothetical candidates for adjusting to a stress-specific response.

Conclusions/Significance

Network-based tools allowed the identification of stress-dependent and general metabolic correlation networks. This correlation-network-based approach does not rely on major changes in concentration to identify metabolites important for stress adaptation, but rather on the changes in network properties with respect to metabolites. This should represent a useful complementary technique in addition to more classical approaches.     

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.     

Metabolic networks are NP-hard to reconstruct

High-throughput data from various omics and sequencing techniques have rendered the automated metabolic network reconstruction a highly relevant problem. Our approach reflects the inherent probabilistic nature of the steps involved in metabolic network reconstruction. Here, the goal is to arrive at networks which combine probabilistic information with the possibility to obtain a small number of disconnected network constituents by reduction of a given preliminary probabilistic metabolic network. We define automated metabolic network reconstruction as an optimization problem on four-partite graph (nodes representing genes, enzymes, reactions, and metabolites) which integrates: (1) probabilistic information obtained from the existing process for metabolic reconstruction from a given genome, (2) connectedness of the raw metabolic network, and (3) clustering of components in the reconstructed metabolic network. The practical implications of our theoretical analysis refer to the quality of reconstructed metabolic networks and shed light on the problem of finding more efficient and effective methods for automated reconstruction. Our main contributions include: a completeness result for the defined problem, polynomial-time approximation algorithm, and an optimal polynomial-time algorithm for trees. Moreover, we exemplify our approach by the reconstruction of the sucrose biosynthesis pathway in Chlamydomonas reinhardtii.     

GOLD.db: genomics of lipid-associated disorders database

Background  

The GOLD.db (Genomics of Lipid-Associated Disorders Database) was developed to address the need for integrating disparate information on the function and properties of genes and their products that are particularly relevant to the biology, diagnosis management, treatment, and prevention of lipid-associated disorders.     

BHK 21 C13 cells for Aujeszky’s disease virus production using the multiple harvest process

Production of Aujeszky’s disease virus (ADV) from BHK 21 C13 suspension cells using a simple harvest and multiple harvest process mode was examined. We studied growth kinetics of BHK 21 C31 cells in 750 ml spinner flask containing 500 ml of culture medium. In the simple harvest process of ADV production, 425 ml of virus harvest was obtained with a virus titer of 10^6.4 TCID₅₀ ml⁻¹ which corresponds to 10,676 doses of vaccine. The multiple harvest process resulted in 850 ml of virus harvest with a virus titer of 10^6.5 TCID₅₀ ml⁻¹ corresponding to 26,877 AD vaccine doses. In conclusion, the multiple harvest process mode using BHK 21 C13 can be considered as a favorable process to produce ADV.     

Functionalization of guanosine and 2'-deoxyguanosine at C6: a modified Appel process and S(N)Ar displacement of imidazole

Treatment of sugar-protected 2-N-trityl derivatives of guanosine and 2'-deoxyguanosine with imidazole/triphenylphosphine/iodine/ethyldiisopropylamine gives the corresponding 6-(imidazol-1-yl)-2-(tritylamino)purine nucleosides. S(N)Ar displacement of the imidazole moiety with nucleophiles provides 2-amino-6-substituted-purine nucleosides and 2'-deoxynucleosides.