Raman Microspectroscopic Analysis of Selenium Bioaccumulation by Green Alga Chlorella vulgaris.

Selenium (Se) is an element with many commercial applications as well as an essential micronutrient. Dietary Se has antioxidant properties and it is known to play a role in cancer prevention. However, the general population often suffers from Se deficiency. Green algae, such as Chlorella vulgaris, cultivated in Se-enriched environment may be used as a food supplement to provide adequate levels of Se. We used Raman microspectroscopy (RS) for fast, reliable, and non-destructive measurement of Se concentration in living algal cells. We employed inductively coupled plasma-mass spectrometry as a reference method to RS and we found a substantial correlation between the Raman signal intensity at 252 cm-1 and total Se concentration in the studied cells. We used RS to assess the uptake of Se by living and inactivated algae and demonstrated the necessity of active cellular transport for Se accumulation. Additionally, we observed the intracellular Se being transformed into an insoluble elemental form, which we further supported by the energy-dispersive X-ray spectroscopy imaging.

The efficiency of antineoplastic drug contamination removal by widely used disinfectants-laboratory and hospital studies.

OBJECTIVE: Antineoplastic drugs (ADs) pose risks to healthcare staff. Surface disinfectants are used in hospitals to prevent microbial contamination but the efficiency of disinfectants to degrade ADs is not known. We studied nine disinfectants on ten ADs in the standardized laboratory and realistic in situ hospital conditions. METHODS: A survey in 43 hospitals prioritized nine most commonly used disinfections based on different ingredients. These were tested on inert stainless steel and in situ on contaminated hospital flooring. The effects against ten ADs were studied by LC-MS/MS (Cyclophosphamide CP; Ifosfamide IF; Capecitabine CAP; Sunitinib SUN; Methotrexate MET; Doxorubicin DOX; Irinotecan IRI; Paclitaxel PX; 5-Fluorouracil FU) and ICP-MS (Pt as a marker of platinum-based ADs). RESULTS: Monitoring of the floor contamination in 26 hospitals showed that the most contaminated are the outpatient clinics that suffer from a large turnover of staff and patients and have limited preventive measures. The most frequent ADs were Pt, PX, FU and CP with maxima exceeding the recommended 1 ng/cm2 limit by up to 140 times. IRI, FU, MET, DOX and SUN were efficiently removed by hydrolysis in clean water and present thus lower occupational risk. Disinfectants based on hydrogen peroxide were efficient against PX and FU (> 70% degradation) but less against other ADs, such as carcinogenic CP or IF, IRI and CAP. The most efficient were the active chlorine and peracetic acid-based products, which however release irritating toxic vapors. The innovative in situ testing of ADs previously accumulated in hospital flooring showed highly problematic removal of carcinogenic CP and showed that alcohol-based disinfectants may mobilize persistent ADs contamination from deeper floor layers. CONCLUSION: Agents based on hydrogen peroxide, peracetic acid, quaternary ammonium salts, glutaraldehyde, glucoprotamine or detergents can be recommended for daily use for both disinfection and AD decontamination. However, they have variable efficiencies and should be supplemented by periodic use of strong chlorine-based disinfectants efficient also against the carcinogenic and persistent CP.

Selenium Incorporation to Amino Acids in Chlorella Cultures Grown in Phototrophic and Heterotrophic Regimes.

Microalgae accumulate bioavailable selenium-containing amino acids (Se-AAs), and these are useful as a food supplement. While this accumulation has been studied in phototrophic algal cultures, little data exists for heterotrophic cultures. We have determined the Se-AAs content, selenium/sulfur (Se/S) substitution rates, and overall Se accumulation balance in photo- and heterotrophic Chlorella cultures. Laboratory trials revealed that heterotrophic cultures tolerate Se doses ∼8-fold higher compared to phototrophic cultures, resulting in a ∼2-3-fold higher Se-AAs content. In large-scale experiments, both cultivation regimes provided comparable Se-AAs content. Outdoor phototrophic cultures accumulated up to 400 µg g-1 of total Se-AAs and exhibited a high level of Se/S substitution (5-10%) with 30-60% organic/total Se embedded in the biomass. A slightly higher content of Se-AAs and ratio of Se/S substitution was obtained for a heterotrophic culture in pilot-scale fermentors. The data presented here shows that heterotrophic Chlorella cultures provide an alternative for Se-enriched biomass production and provides information on Se-AAs content and speciation in different cultivation regimes.

In vitro bioaccessibility of selenoamino acids from selenium (Se)-enriched Chlorella vulgaris biomass in comparison to selenized yeast; a Se-enriched food supplement; and Se-rich foods.

Selenium (Se) is an indispensable microelement in our diet and health issues resulting from deficiencies are well documented. Se-containing food supplements are available on the market including Se-enriched Chlorella vulgaris (Se-Chlorella) which accumulates Se in the form of Se-amino acids (Se-AAs). Despite its popular uses, data about the bioaccessibility of Se-AAs from Se-Chlorella are completely missing. In the present study, gastrointestinal digestion times were optimized and the in vitro bioaccessibility of Se-AAs in Se-Chlorella, Se-yeast, a commercially available Se-enriched food supplement (Se-supplement) and Se rich foods (Se-foods) were compared. Higher bioaccessibility was found in Se-Chlorella (∼49%) as compared to Se-yeast (∼21%), Se-supplement (∼32%) and Se-foods. The methods used in production of Se-Chlorella biomass were also investigated. We found that disintegration increased bioaccessibility whereas the drying process had no effect. Similarly, temperature treatment by microwave oven also increased bioaccessibility whereas boiling water did not.

Analysis of mercury and other heavy metals accumulated in lichen Usnea antarctica from James Ross Island, Antarctica.

The study was designed to investigate the content and distribution of selected heavy metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Fe, Pb and Zn) in samples of fruticose macrolichen Usnea antarctica from James Ross Island. A special emphasis was devoted to mercury and its species (elemental mercury and methylmercury). It was found that mercury contents were relatively high (up to 2.73 mg kg(-1) dry weight) compared to other parts of the Antarctic Peninsula region, while the concentrations of most other elements were within reported ranges. Mercury contents in lichens originating from the interior were higher than those from the coast, which is probably the result of local microclimate conditions. Similar trends were observed for Hg(0) and MeHg(+), whose contents were up to 0.14 and 0.098 mg kg(-1) dry weight, respectively. While mercury did not show a significant correlation with any other element, the mutual correlation of some litophile elements probably refers to the influence on thalli of resuspended weathered material. The influence of habitat and environmental conditions could play an essential role in the bioaccumulation of contaminants rather than just the simple presence of sources. Thus, the study of the thalli of this species can bring a new perspective on the interpretation of contaminant accumulation in lichens of the polar region.

Utilisation of iodine from different sources by sows and their progeny.

OBJECTIVES: The aim of the study was to compare iodine utilization from different sources by sows and their progeny and the levels of T3 and T4 in their serum. DESIGN: Pregnant Czech Large White × Landrace sows were fed with an experimental KPK diet (a diet for lactating sows) 14 days before parturition until weaning (at a piglet age of 28 days). In group A (n=50, 10 sows, 40 piglets) the feed was supplemented with KI (0.6 mg of iodine per kg of feed). Iodine enriched alga Chlorella spp. (0.6 mg of iodine per kg of feed) was used as a supplement in group B (n=50, 10 sows, 40 piglets). In group C (n=50, 10 sows, 40 piglets) the sows were injected i.m. with IFAE at a dose of 100 mg of iodine per sow. Iodine, T3 and T4 were measured in each group for comparison of iodine utilization. RESULTS: The use of IFAE resulted in higher serum concentrations in sows compared to KI and alga. In contrast, iodine concentrations in milk and piglets were lower when IFAE were used. We found a wide variation in the concentrations of T3 and T4 in the serum of piglets in all groups. CONCLUSION: Our results indicate a good utilization of iodized oil by sows. However, its transfer into milk is lower compared to the other iodine sources.