When cholesterol is not cholesterol: a note on the enzymatic determination of its concentration in model systems containing vegetable extracts

Background: Experimental evidences demonstrate that vegetable derived extracts inhibit cholesterol absorption in the gastrointestinal tract. To further explore the mechanisms behind, we modeled duodenal contents with several vegetable extracts. Results: By employing a widely used cholesterol quantification method based on a cholesterol oxidase-peroxidase coupled reaction we analyzed the effects on cholesterol partition. Evidenced interferences were analyzed by studying specific and unspecific inhibitors of cholesterol oxidase-peroxidase coupled reaction. Cholesterol was also quantified by LC/MS. We found a significant interference of diverse (cocoa and tea-derived) extracts over this method. The interference was strongly dependent on model matrix: while as in phosphate buffered saline, the development of unspecific fluorescence was inhibitable by catalase (but not by heat denaturation), suggesting vegetable extract derived H2O2 production, in bile-containing model systems, this interference also comprised cholesterol-oxidase inhibition. Several strategies, such as cholesterol standard addition and use of suitable blanks containing vegetable extracts were tested. When those failed, the use of a mass-spectrometry based chromatographic assay allowed quantification of cholesterol in models of duodenal contents in the presence of vegetable extracts. Conclusions: We propose that the use of cholesterol-oxidase and/or peroxidase based systems for cholesterol analyses in foodstuffs should be accurately monitored, as important interferences in all the components of the enzymatic chain were evident. The use of adequate controls, standard addition and finally, chromatographic analyses solve these issues.

Esterification of oleic acid catalayzed by an Aspergillus niger strain. Influence of water activity and alcohol concentration

Effects of water activity and 1-propanol concentration on synthesis of propyl oleate from oleic acid using Aspergillus niger cell-bound lipases in isooctane are described. A. niger produces lipases (EC 3.1.1.3) which partly bind to the mycelium during growth. Ester production was monitored for 72 hours at different 1-propanol concentrations and water activities. Aliquots were sequentially withdrawn and propyl esters were quantified using GC and methyl palmitate as an internal standard. In all assayed conditions A. niger cell-bound lipases catalysed propyl oleate synthesis, but at different degrees.

The Saccharomyces cerevisiae Hot1p regulated gene YHR087W (HGI1) has a role in translation upon high glucose concentration stress.

Background While growing in natural environments yeasts can be affected by osmotic stress provoked by high glucose concentrations. The response to this adverse condition requires the HOG pathway and involves transcriptional and posttranscriptional mechanisms initiated by the phosphorylation of this protein, its translocation to the nucleus and activation of transcription factors. One of the genes induced to respond to this injury is YHR087W. It encodes for a protein structurally similar to the N-terminal region of human SBDS whose expression is also induced under other forms of stress and whose deletion determines growth defects at high glucose concentrations. Results In this work we show that YHR087W expression is regulated by several transcription factors depending on the particular stress condition, and Hot1p is particularly relevant for the induction at high glucose concentrations. In this situation, Hot1p, together to Sko1p, binds to YHR087W promoter in a Hog1p-dependent manner. Several evidences obtained indicate Yhr087wp"s role in translation. Firstly, and according to TAP purification experiments, it interacts with proteins involved in translation initiation. Besides, its deletion mutant shows growth defects in the presence of translation inhibitors and displays a slightly slower translation recovery after applying high glucose stress than the wild type strain. Analyses of the association of mRNAs to polysome fractions reveals a lower translation in the mutant strain of the mRNAs corresponding to genes GPD1, HSP78 and HSP104. Conclusions The data demonstrates that expression of Yhr087wp under high glucose concentration is controlled by Hot1p and Sko1p transcription factors, which bind to its promoter. Yhr087wp has a role in translation, maybe in the control of the synthesis of several stress response proteins, which could explain the lower levels of some of these proteins found in previous proteomic analyses and the growth defects of the deletion strain. Keywords: Saccharomyces cerevisiae; High glucose osmotic stress; Gene YHR087W; Gene expression; Translation; Hot1p; Hog1p; Polysomes

Daily precipitation concentration across Europe 1971-2010

Daily Precipitation Concentration Index (CI) was used in this paper to investigate the statistical structure of daily precipitation across Europe based on 530 daily rainfall series for the period 1971-2010. Annual CI shows a North- West to South-East gradient (excluding Turkey and Greece). The same gradient is also observed in winter, spring and autumn, while in summer the gradient is North-South. Highest annual and seasonal daily concentrations of rainfall were detected in the western Mediterranean basin, mainly along Spanish and French coastlands. Latitude and distance from the sea seems to play a major role on spatial CI distribution; at subregional scale also relief plays an important role. The Mann-Kendall test did not identify uniform significant pattern in temporal trend across Europe for 1971-2010 period. The only broad areas with increasing annual and seasonal CI values are located in northern and south-western France and northern coastlands of the Iberian Peninsula. This findings suggest that daily precipitation distribution has not significantly changed during the 1971-2010 over Europe.

Pineapple (Ananas comosus) cv. pérola ex vitro growth and mycorrhizal colonization affected by in vitro sucrose concentration

The aim of this study was to evaluate the effect of sucrose concentration in the culture medium on growth and on the establishment of mycorrhizas during the acclimatization of pineapple cv. Pérola. The plantlets were micropropagated in MS culture medium with 0, 10, 20 and 30 g L-1 of sucrose and then they were acclimatized during 12 weeks under greenhouse conditions, in a sandy soil - compost mixture, uninoculated or inoculated with a Rhizophagus clarus isolate. Plantlets from the culture medium with 20 g and 30 g of sucrose L-1 showed higher shoot and root biomass than those from sugar-free medium. Mycorrhizal colonization was lower in plantlets micropropagated in sucrose-free medium, but the intensity of arbuscules did not differ among treatments. In the 12-week period of acclimatization, mycorrhizal colonization had no effect on plant biomass.

Effects of iodinated contrast agent, xylocaine and gadolinium concentration on the signal emitted in magnetic resonance arthrography: a samples study

Objective:To investigate the effects of dilution of paramagnetic contrast agent with iodinated contrast and xylocaine on the signal intensity during magnetic resonance arthrography, and to improve the paramagnetic contrast agent concentration utilized in this imaging modality.Materials and Methods:Samples specially prepared for the study with three different concentrations of paramagnetic contrast agent diluted in saline, iodinated contrast agent and xylocaine were imaged with fast spin echo T1-weighted sequences with fat saturation. The samples were placed into flasks and graphical analysis of the signal intensity was performed as a function of the paramagnetic contrast concentration.Results:As compared with samples of equal concentrations diluted only with saline, the authors have observed an average signal intensity decrease of 20.67% for iodinated contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium concentration in the samples caused decrease in signal intensity with all the dilutions.Conclusion:Minimizing the use of iodinated contrast media and xylocaine and/or the use of a gadolinium concentration of 2.5 mmol/L diluted in saline will improve the sensitivity of magnetic resonance arthrography.

Intercontinental fligths from European Airports: Towards hub concentration or not?

This paper empirically analyzes changes in the supply of non-stop intercontinental flights from European airports. We take advantage of OAG data for air services from a rich sample of European airports to intercontinental destinations in the period 2004-2008. Results of the empirical analysis indicate a tendency towards a more balanced distribution of intercontinental flights across European airports. We also find that the demographic size of a region, its sector specialization, the political role of its central city and the proportion of connecting traffic explain the amount of and changes in long-haul air services supplied from European airports.

Maritime transportation in the Gulf of Finland in 2007 and in 2015

The Gulf of Finland is said to be one of the densest operated sea areas in the world. It is a shallow and economically vulnerable sea area with dense passenger and cargo traffic of which petroleum transports have a share of over 50 %. The winter conditions add to the risks of maritime traffic in the Gulf of Finland. It is widely believed that the growth of maritime transportation will continue also in the future. The Gulf of Finland is surrounded by three very different national economies with, different maritime transportation structures. Finland is a country of high GDP/per capita with a diversified economic structure. The number of ports is large and the maritime transportation consists of many types of cargoes: raw materials, industrial products, consumer goods, coal and petroleum products, and the Russian transit traffic of e.g. new cars and consumer goods. Russia is a large country with huge growth potential; in recent years, the expansion of petroleum exports has lead to a strong economic growth, which is also apparent in the growth of maritime transports. Russia has been expanding its port activities in the Gulf of Finland and it is officially aiming to transport its own imports and exports through the Russian ports in the future; now they are being transported to great extend through the Finnish, Estonian and other Baltic ports. Russia has five ports in the Gulf of Finland. Estonia has also experienced fast economic growth, but the growth has been slowing down already during the past couples of years. The size of its economy is small compared to Russia, which means the transported tonnes cannot be very massive. However, relatively large amounts of the Russian petroleum exports have been transported through the Estonian ports. The future of the Russian transit traffic in Estonia looks nevertheless uncertain and it remains to be seen how it will develop and if Estonia is able to find replacing cargoes if the Russian transit traffic will come to an end in the Estonian ports. Estonia’s own import and export consists of forestry products, metals or other raw materials and consumer goods. Estonia has many ports on the shores of the Gulf of Finland, but the port of Tallinn dominates the cargo volumes. In 2007, 263 M tonnes of cargoes were transported in the maritime traffic in the Gulf of Finland, of which the share of petroleum products was 56 %. 23 % of the cargoes were loaded or unloaded in the Finnish ports, 60 % in the Russian ports and 17 % in the Estonian ports. The largest ports were Primorsk (74.2 M tonnes) St. Petersburg (59.5 M tonnes), Tallinn (35.9 M tonnes), Sköldvik (19.8 M tonnes), Vysotsk (16.5 M tonnes) and Helsinki (13.4 M) tonnes. Approximately 53 600 ship calls were made in the ports of the Gulf of Finland. The densest traffic was found in the ports of St. Petersburg (14 651 ship calls), Helsinki (11 727 ship calls) and Tallinn (10 614 ship calls) in 2007. The transportation scenarios are usually based on the assumption that the amount of transports follows the development of the economy, although also other factors influence the development of transportation, e.g. government policy, environmental aspects, and social and behavioural trends. The relationship between the development of transportation and the economy is usually analyzed in terms of the development of GDP and trade. When the GDP grows to a certain level, especially the international transports increase because countries of high GDP produce, consume and thus transport more. An effective transportation system is also a precondition for the economic development. In this study, the following factors were taken into consideration when formulating the future scenarios: maritime transportation in the Gulf of Finland 2007, economic development, development of key industries, development of infrastructure and environmental aspects in relation to maritime transportation. The basic starting points for the three alternative scenarios were: • the slow growth scenario: economic recession • the average growth scenario: economy will recover quickly from current instability • the strong growth scenario: the most optimistic views on development will realize According to the slow growth scenario, the total tonnes for the maritime transportation in the Gulf of Finland would be 322.4 M tonnes in 2015, which would mean a growth of 23 % compared to 2007. In the average growth scenario, the total tonnes were estimated to be 431.6 M tonnes – a growth of 64 %, and in the strong growth scenario 507.2 M tonnes – a growth of 93%. These tonnes were further divided into petroleum products and other cargoes by country, into export, import and domestic traffic by country, and between the ports. For petroleum products, the share of crude oil and oil products was estimated and the number of tanker calls in 2015 was calculated for each scenario. However, the future development of maritime transportation in the GoF is dependent on so many societal and economic variables that it is not realistic to predict one exact point estimate value for the cargo tonnes for a certain scenario. Plenty of uncertainty is related both to the degree in which the scenario will come true as well as to the cause-effect relations between the different variables. For these reasons, probability distributions for each scenario were formulated by an expert group. As a result, a range for the total tonnes of each scenario was formulated and they are as follows: the slow growth scenario: 280.8 – 363 M tonnes (expectation value 322.4 M tonnes)

New methods for the concentration of viruses from urban sewage using quantitative PCR.

Viruses are among the most important pathogens present in water contaminated with feces or urine and represent a serious risk to human health. Four procedures for concentrating viruses from sewage have been compared in this work, three of which were developed in the present study. Viruses were quantified using PCR techniques. According to statistical analysis and the sensitivity to detect human adenoviruses (HAdV), JC polyomaviruses (JCPyV) and noroviruses genogroup II (NoV GGII): (i) a new procedure (elution and skimmed-milk flocculation procedure (ESMP)) based on the elution of the viruses with glycine-alkaline buffer followed by organic flocculation with skimmed-milk was found to be the most efficient method when compared to (ii) ultrafiltration and glycine-alkaline elution, (iii) a lyophilization-based method and (iv) ultracentrifugation and glycine-alkaline elution. Through the analysis of replicate sewage samples, ESMP showed reproducible results with a coefficient of variation (CV) of 16% for HAdV, 12% for JCPyV and 17% for NoV GGII. Using spiked samples, the viral recoveries were estimated at 30-95% for HAdV, 55-90% for JCPyV and 45-50% for NoV GGII. ESMP was validated in a field study using twelve 24-h composite sewage samples collected in an urban sewage treatment plant in the North of Spain that reported 100% positive samples with mean values of HAdV, JCPyV and NoV GGII similar to those observed in other studies. Although all of the methods compared in this work yield consistently high values of virus detection and recovery in urban sewage, some require expensive laboratory equipment. ESMP is an effective low-cost procedure which allows a large number of samples to be processed simultaneously and is easily standardizable for its performance in a routine laboratory working in water monitoring. Moreover, in the present study, a CV was applied and proposed as a parameter to evaluate and compare the methods for detecting viruses in sewage samples.