Toenail mercury levels positively correlate with obesity and abdominal obesity among Korean adults

BackgroundAlthough previous studies have shown that short-term exposure to mercury is associated with obesity, it should be noted that mercury is not easily released and that it constantly accumulates in the body. However, few studies have explored the association between chronic mercury exposure and obesity. This study aimed to examine the association between chronic mercury exposure and obesity in Korean adults.MethodsThe study used baseline data from the Trace Element Study of Korean Adults in Yeungnam area. A total of 495 participants aged 40–69 years who provided the required information (demographic, diet, lifestyle, toenail mercury levels, and health examination results) were included. Toenail mercury levels were measured using neutron-activation analysis. Body mass index and waist circumference were obtained from medical examination. Multivariable-adjusted logistic regression and restricted cubic spline regression were used in the analysis.ResultsIn the fully adjusted logistic regression models, participants with the highest toenail mercury levels had a higher prevalence of obesity (odds ratio [OR]: 3.26, 95 % confidence interval [CI]: 1.79–5.93) and abdominal obesity (OR: 2.30, 95 % CI: 1.15–4.59). In the cubic spline regression model, linear relationships were confirmed between increased toenail mercury levels and higher prevalence of obesity and abdominal obesity (all p > 0.05 for nonlinearity).ConclusionsIn summary, chronic mercury exposure was associated with higher prevalence of obesity and abdominal obesity in Korean adults. Therefore, the development of public health interventions against environmental exposure of foods is required to manage and prevent obesity.     

Inhibition of cell wall degrading cellulase enzyme – the incitant of anthracnose disease caused by Colletotrichum capsici on capsicum fruit

Abstract

Cell wall degrading enzymes, namely cellulase, were detected in senescence and diseased macerated tissue of capsicum fruit. Their purported role in pathogenicity of Colletotrichum capsici was studied in detail. In situ production of cellulase concentration ranging from 80?–?360 μg was recorded in healthy capsicum fruit during storage. Production of this enzyme increased with an increase in the storage period. Increase in production of cellulase enzyme was recorded in infected tissue from seventh day after inoculation. Increased productions of this cell wall degrading enzyme coincide with disease manifestation and rapid progress of decay on capsicum fruit. Production of cellulase enzyme ranged from 80?–?360 μg. Conidial germination with advance of incubation period and further growth of C. capsici increased the production of cellulase enzyme. Conidia of C. capsici showed a gradual increase in production of cellulase enzyme with an increase in the incubation period. Treatment of capsicum fruit with different concentrations of calcium chloride, lactic acid and sorbic acid showed a 100%, 85.1% and 83.2% decrease in production of cellulase enzyme at the concentration of 1000 ppm, 500 ppm and 1000 ppm respectively.     

Evidence of high mercury accumulation in the cell wall of the liverwort Jungermannia vulcanicola Steph. to form particles of a mercury-sulphur compound

Abstract

Transmission electron microscope and X-ray microanalyser studies were carried out on the cells of mercury accumulating aquatic liverwort Jungermannia vulcanicola from Kashiranashigawa Stream.

The mercury which is accumulated from stream water is mainly located in the cell wall in the form of electron dense particles having the size range 0.01 – 0.1 μm up to 0.2 μm. The chemical form of the mercury in the electron dense particles is a mercury-sulphur compound, probably mercuric sulphide, which is not toxic to living organisms.     

Induction of non-protein thiols and phytochelatins by cadmium in Eichhornia crassipes

Abstract

Impact of root Cd concentration on production of cysteine, non-protein thiols (NP-SH), glutathione (GSH), reduced glutathione (GSSG), and phytochelatins (PCs) in Eichhornia crassipes exposed to different dilutions of brass and electroplating industry effluent (25%, 50%, and 75%), and synthetic metal solutions of Cd alone (1, 2.5, and 3.5?ppm) and with Cr (1?ppm Cd + 1?ppm Cr, 2.5?ppm Cd + 3?ppm Cr, and 3.5?ppm Cd + 4?ppm Cr) was assessed in a 45?days study. Different treatments were used to understand and compare differential antioxidant defense response of plant under practical drainage (effluent) and experimental synthetic solutions. The production of NP-SH and cysteine was maximum under 2.5?ppm Cd + 3?ppm Cr treatments i.e., 1.78?µmol/g fw and 288?nmol/g fw, respectively. The content of GSH declined whereas that of GSSG increased progressively with exposure duration in all treatments. HPLC chromatograms revealed that the concentrations of PC2, PC3, and PC4 (248, 250, and 288?nmol-SH equiv.g^?1 fw, respectively) were maximum under 1?ppm Cd, 1?ppm Cd + 1?ppm Cr, and 2.5?ppm Cd + 3?ppm Cr treatments, respectively. PC2, PC3, and PC4 concentrations increased with Cd accumulation in the range 812–1354?µg/g dry wt, 1354–2032?µg/g dry wt and 2032–3200?µg/g dry wt, respectively. Thus, the study establishes a direct proportionality relationship between concentration/length of phytochelatins and root Cd concentrations, upto threshold limits, in E. crassipes.     

Thiol/disulphide homeostasis in pregnant women with Familial Mediterranean fever

Objective: To investigate the presence of oxidative stress (OS) in pregnant women with Familial Mediterranean fever (FMF) in the first trimester by evaluating thiol/disulphide homeostasis.

Study design: A total of 31 pregnant women with a diagnosis of FMF, between 11⁰ and 13⁶ weeks of gestation, were compared with 51 healthy pregnant controls at the same gestational weeks. A recently defined method was used to measure plasma native thiol, total thiol and disulphide levels.

Results: There were no differences between groups in terms of maternal age, body mass index and numbers of gravida and parity. Antenatal complications (45.2% vs. 9.8%, P?=?0.001) and primary caesarean section (22.6% vs. 5.9%, P?=?0.037) were higher in the FMF group. Pregnant women with FMF had significantly lower first trimester serum levels of native thiol (297.5?μmol/l (153.2–441.8) vs. 366.1?μmol/l (288.7–432.4), P?=?0.000), total thiol (327.2?μmol/l (171.0–471.0) vs. 389.9?μmol/l (317.1–449.8), P?=?0.000) and higher levels of disulphide (14.2?±?4.5?μmol/l vs. 12.4?±?3.4?μmol/l, P?=?0.045). No differences were found in these parameters among FMF patients with and without antenatal complications.

Conclusions: The main outcome demonstrates a relation between OS and pregnant women with FMF in the first trimester of gestation. OS in the first trimester may be a major aetiological factor of unfavourable pregancy outcomes in this group of patients.     

Portable X-ray fluorescence of zinc applied to human toenail clippings

Zinc is an essential trace element in humans. Zinc deficiency can result in a range of serious medical conditions which include effects on growth and development, the immune system, the central nervous system, and the gastrointestinal system. Diagnosis of zinc deficiency is often precluded by the lack of a noninvasive and reliable biomarker. Zinc concentration in nail is considered an emerging biomarker of zinc status in humans. Whether zinc in nail accurately reflects zinc status is beyond the scope of the current study, but is an important research question. The development of a portable method to quickly assess zinc concentration from a single nail clipping could be a useful advance. In this study, single toenail clippings from 60 individuals living in Atlantic Canada were measured for zinc using a portable X-ray fluorescence (XRF) technique. These samples were obtained from the Atlantic PATH cohort, part of the largest chronic disease study ever performed in Canada. Each toenail clipping was measured using three 300 s trials with a mono-energetic portable XRF system. Results were then assessed using two different approaches to the XRF analysis: (1) factory-calibrated zinc concentrations were output from each trial, and (2) energy spectra were analyzed for the characteristic X-rays resulting from zinc. Following the measurement of zinc using the non-destructive portable XRF method, the same clippings were measured for zinc concentration using the “gold standard” technique of inductively coupled plasma-mass spectrometry (ICP-MS). A linear equation of best fit was determined for the relationship between average XRF output zinc concentration and ICP-MS zinc concentration, with a correlation coefficient r = 0.60. Similarly, a linear equation of best fit was found for the relationship between a normalized XRF energy spectrum zinc signal and ICP-MS zinc concentration, with a correlation coefficient r = 0.68. Individual ICP-MS zinc concentrations ranged from 32 μg/g to 140 μg/g, with a population average of 85 μg/g. The results of this study indicate that portable XRF is a sensitive method for the measurement of zinc in a single nail clipping, and provides a reasonable estimation of zinc concentration. Further method development is required before portable XRF be considered a routine alternative to ICP-MS for the assessment of zinc in nail clippings.     

Human nails as a biomarker of arsenic exposure from well water in Inner Mongolia: comparing atomic fluorescence spectrometry and neutron activation analysis

Abstract

Arsenic (As) is found naturally in the geological strata within the Ba Men Region of Inner Mongolia, China. A study was conducted to compare the total As measurements from two analytical techniques: instrumental neutron activation analysis (INAA) and atomic fluorescence spectrometry (AFS), and to verify nails as an exposure biomarker in this population. In 1999, nail and water samples were collected in a pilot study. Fingernails and toenails were pooled from 32 participants and analysed for total As by both INAA and AFS. Mean nail As values were 14.8±2.4 and 19.4±2.8 µg?g^?1 (±SEM) for INAA and AFS, respectively. Results from these two methods were significantly correlated (r=0.93, p<0.0001). In 2000, a second study was conducted and INAA was used to measure total As in toenails from 314 Ba Men residents. Well water samples were collected from 121 households and analysed by AFS. A significant correlation was observed between toenail and well water As (r=0.84, p<0.0001). Based on the results, INAA was significantly correlated with AFS and proved to be a reliable measure of nail As levels. In this population, toenail samples are a useful internal As exposure biomarker from drinking water sources.     

Rapid label-free detection of E. coli using a novel SPR biosensor containing a fragment of tail protein from phage lambda

Abstract

In efforts to speed up the assessment of microorganisms, researchers have sought to use bacteriophages as a biosensing tool, due to their host-specificity, wide abundance, and safety. However, the lytic cycle of the phage has limited its efficacy as a biosensor. Here, we cloned a fragment of tail protein J from phage lambda and characterized its binding with the host, E. coli K-12, and other microorganism. The N-terminus of J was fused with a His-tag (6HN-J), overexpressed, purified, and characterized using anti-His monoclonal antibodies. The purified protein demonstrated a size of ～38?kDa upon SDS-PAGE and bound with the anti-His monoclonal antibodies. ELISA, dot blot, and TEM data revealed that it specifically bound to E. coli K-12, but not to Pseudomonas aeruginosa. The observed protein binding occurred over a concentration range of 0.01–5?μg/ml and was found to inhibit the in vivo adsorption of phage to host cells. This specific binding was exploited by surface plasmon resonance (SPR) to generate a novel 6HN-J-functionalized SPR biosensor. This biosensor showed rapid label-free detection of E. coli K-12 in the range of 2?×?10⁴ ?2?×?10⁹ CFU/ml, and exhibited a lower detection limit of 2?×?10⁴ CFU/ml.     

Nano-transfersomal formulations for transdermal delivery of asenapine maleate: in vitro and in vivo performance evaluations

Context: Asenapine maleate (ASPM) is an antipsychotic drug for the treatment of schizophrenia and bipolar disorder. Extensive metabolism makes the oral route inconvenient for ASPM.

Objective: The objective of this study is to increase ASPM bioavailability via transdermal route by improving the skin permeation using combined strategy of chemical and nano-carrier (transfersomal) based approaches.

Materials and methods: Transfersomes were prepared by the thin film hydration method using soy-phosphatidylcholine (SPC) and sodium deoxycholate (SDC). Transfersomes were characterized for particle size, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, surface morphology, and in vitro skin permeation studies. Various chemical enhancers were screened for skin permeation enhancement of ASPM. Optimized transfersomes were incorporated into a gel base containing suitable chemical enhancer for efficient transdermal delivery. In vivo pharmacokinetic study was performed in rats to assess bioavailability by transdermal route against oral administration.

Results and discussion: Optimized transfersomes with drug:SPC:SDC weight ratio of 5:75:10 were spherical with an average size of 126.0?nm, PDI of 0.232, ZP of??43.7?mV, and entrapment efficiency of 54.96%. Ethanol (20% v/v) showed greater skin permeation enhancement. The cumulative amount of ASPM permeated after 24?h (Q₂₄) by individual effect of ethanol and transfersome, and in combination was found to be 160.0, 132.9, and 309.3?μg, respectively, indicating beneficial synergistic effect of combined approach. In vivo pharmacokinetic study revealed significant (p?Conclusion: Dual strategy of permeation enhancement was successful in increasing the transdermal permeation and bioavailability of ASPM.     

No association between the vitamin D pathway gene polymorphisms and bone biomarkers response to calcium and low dose calcitriol supplementation in postmenopausal Chinese women: a one-year prospective study

Abstract

Introduction: The aim of the study was to explore the association between the vitamin D pathway gene variations and the bone biomarkers response to calcium and low dose calcitriol supplementation in postmenopausal Chinese women.

Methods: A total of 110 healthy postmenopausal Chinese women (61.51?±?6.93?years) were enrolled. The participants were supplemented with calcium (600?mg/d) and calcitriol (0.25?μg/d), for 1?year. Four biomarkers, serum levels of beta C-terminal cross-linked telopeptides of type I collagen (β-CTX), amino-terminal propeptide of type I collagen (P1NP), parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] were measured at baseline and 12-month follow-up. Multivariate regression models were established to explore the statistical association between the change rate of the four biomarkers and 15?key genes within the vitamin D metabolic pathway.

Results: This exclusion process left 98 participants for analysis. Serum levels of P1NP, β-CTX and PTH were significantly decreased at the 12-month follow-up (all p?<?0.05). Serum 25(OH)D level had no significant change (p?>?0.05). No association was found between the vitamin D pathway gene polymorphisms and bone biomarkers response to calcium and low dose calcitriol supplementation.

Conclusions: Genetic background of postmenopausal Chinese women might not influence supplemental response of the biomarkers to calcium and low dose calcitriol.     

Variability of Mercury Concentrations in Soil and Leaves of Acer plantanoides and Tilia platyphyllos in Poznań City,Poland

The paper presents the results of research on mercury in the soil and leaves of maple (Acer plantanoides) and linden (Tilia platyphyllos) collected in the four districts of the city of Poznań (Poland), which differ in terms of anthropogenic pressure. The average concentration of mercury in soil was 132 μg kg^?1. The highest concentration of mercury was determined in Tilia platyphyllos (233 μg kg^?1), whereas in Acer plantanoides it amounted to 207 μg kg^?1. Based on the study, it was found that the highest concentration of mercury in the investigated leaf species was observed in the samples collected in the districts of Grunwald, Je?yce, and Old Town. The lowest concentration was observed in the samples collected in the district of New Town. The comparison of the obtained results of mercury concentration in soil and leaf samples was made in terms of anthropogenic pressure in the investigated areas and depending on the studied leaf species. Based on the statistical analysis, it was found that there is no statistically significant relationship between mercury concentration in both studied species of trees. There was, however, a relationship between the mercury concentration in leaves and soil.     

Ethosomes for skin delivery of ropivacaine: preparation,characterization and ex vivo penetration properties

Abstract

Ropivacaine, a novel long-acting local anesthetic, has been proved to own superior advantage. However, Naropin® Injection, the applied form in clinic, can cause patient non-convenience. The purpose of this study was to formulate ropivacaine (RPV) in ethosomes and evaluate the potential of ethosome formulation in delivering RPV transdermally. The RPV-loaded ethosomes were prepared with thin-film dispersion technique and the formulation was characterized in terms of size, zeta potential, differential scanning calorimetry (DSC) analysis and X-ray diffraction (XRD) study. The results showed that the optimized RPV-ethosomes displayed a typical lipid bilayer structure with a narrow size distribution of 73.86?±?2.40?nm and drug loading of 8.27?±?0.37%, EE of 68.92?±?0.29%. The results of DSC and XRD study indicated that RPV was in amorphous state when encapsulated into ethosomes. Furthermore, the results of ex vivo permeation study proved that RPV-ethosomes could promote the permeability in a high-efficient, rapid way (349.0?±?11.5?μg?cm^?2 at 12?h and 178.8?±?7.1?μg?cm^?2 at 0.5?h). The outcomes of histopathology study forecasted that the interaction between ethosomes and skin could loosen the tight conjugation of corneocyte layers and weaken the permeation barrier. In conclusion, RPV-ethosomes could be a promising delivery system to encapsulate RPV and deliver RPV for transdermal administration.     

Burrow depth,carbon dioxide and reproductive success in Sand Martins Riparia riparia

Capsule: Carbon dioxide (CO₂) concentrations in the burrows of Sand Martins Riparia riparia increase with depth but have no detectable impact on fledging success.

Aims: To investigate whether burrow depth and CO₂ concentrations influence reproductive success in Sand Martins.

Methods: We monitored two Sand Martin colonies along the River Lune, Lancashire, UK, to investigate the effect of burrow depth on reproductive success. We also measured CO₂ levels in a sample of burrows to test whether burrow depth predicts CO₂ concentration, and to test for a relationship between CO₂ concentration and breeding success.

Results: Burrow depth was significantly correlated with fledging success, but the correlation was positive in first broods and negative in second broods. The highest CO₂ concentration recorded was 73?650?ppm and the mean concentration across burrows was 31?757?ppm. However, while CO₂ concentrations were positively correlated with burrow depth after controlling for the number and age of nestlings, they were not correlated with reproductive success.

Conclusion: There are reproductive costs associated with deeper burrows in second broods, but these could not be attributed to CO₂ concentrations despite the exceptionally high levels recorded. This study highlights the need for further investigation into gas exchange and the potential impacts of, or adaptations to, CO₂ accumulation in avian burrows.     

Protective effect of rosemary (Rosmarinus officinalis) against diethylnitrosamine-induced renal injury in rats

Abstract

Context: The kidney plays a central role in detoxification and excretion of toxic metabolites, and therefore, is susceptible to toxicity by xenobiotics.

Objective: To investigate the protective effect of Rosmarinus officinalis (rosemary) powder and its essential (volatile) oil against diethylnitrosamine (DEN)-induced renal injury in rats.

Materials and methods: Phenolic and flavonoid components were characterised in rosemary powder using HPLC-UV instrument while rosemary essential oil (E.O) was investigated via GC-MS technique. In rat model, rosemary was administrated orally (in diet) for two months. Lipid profile, antioxidant biomarkers, kidney functions and histopathological examinations were assessed.

Results: Hesperidin (4878.88?ppm) and ellagic acid (403.57?ppm) are among the major phenolic and flavonoid constituents in rosemary powder. Camphor (18.36%) and α-pinene (12.74%) represent the main E.O active ingredients. Rats treated with rosemary E.O showed a significant elevation in serum HDL (28.28%) accompanied by a decrease in LDL (115.47%). A significant decrease in serum creatinine and urea was also reported (69.72 and 109.89%, respectively). Moreover, serum glutathione peroxidise (GSH-Px) activity has been significantly increased. Kidney histopathological examinations confirmed the protective effect against DEN-induced abnormalities.

Conclusion: Rosemary (powder/E.O) was able to reduce or even prevent the severity of diethylnitrosamine-induced renal dysfunction.     

Exposure of preterm neonates to toxic metals during their stay in the Neonatal Intensive Care Unit and its impact on neurodevelopment at 2 months of age

BackgroundPremature neonates might be exposed to toxic metals during their stay in the neonatal intensive care unit (NICU), which could adversely affect neurodevelopment; however, limited evidence is available. The present study was therefore designed to assess the exposure to mercury, lead, cadmium, arsenic, and manganese of preterm neonates who received total parenteral nutrition (TPN) and/or red blood cell (RBC) transfusions during their NICU stay and the risk of neurodevelopment delay at the age of 2 months.MethodsWe recruited 33 preterm neonates who required TPN during their NICU admission. Blood samples were collected for metal analysis at two different time points (admission and before discharge). Metals in the daily TPN received by preterm neonates were analyzed. Neurodevelopment was assessed using the Ages and Stages Questionnaire Edition 3 (ASQ-3).ResultsAll samples of TPN had metal contamination: 96% exceeded the critical arsenic limit (0.3 μg/kg body weight/day); daily manganese intake from TPN for preterm neonates exceeded the recommended dose (1 µg/kg body weight) as it was added intentionally to TPN solutions, raising potential safety concerns. All samples of RBC transfusions exceeded the estimated intravenous reference dose for lead (0.19 µg/kg body weight). Levels of mercury, lead and manganese in preterm neonates at discharge decreased 0.867 µg/L (95% CI, 0.76, 0.988), 0.831 (95%CI, 0.779, 0.886) and 0.847 µg/L (95% CI, 0.775, 0.926), respectively. A decrease in ASQ-3-problem solving scores was associated with higher levels of blood lead in preterm neonates taken at admission (ß = −0.405, 95%CI = −0.655, −0.014), and with plasma manganese (ß = −0.562, 95%CI = −0.995, −0.172). We also observed an association between decreased personal social domain scores with higher blood lead levels of preterm neonates before discharge (ß = −0.537, 95%CI = −0.905, −0.045).ConclusionOur findings provide evidence to suggest negative impacts on the neurodevelopment at 2 months of preterm infants exposed to certain metals, possibly related to TPN intake and/or blood transfusions received during their NICU stay. Preterm neonates may be exposed to levels of metals in utero.     

An easy,inexpensive, and sensitive method for the quantification of chitin in insect peritrophic membrane by image processing

ABSTRACT

Chitin, poly (β-(1→4)-N-acetyl-d-glucosamine), is an important biopolymer for insects that is utilized as a major component of peritrophic membrane. The chitin content in peritrophic membrane is of expedient interest from a pest control perspective, although it is hard to quantify chitin. In this study, we establish a facile method for the quantification of chitin in peritrophic membrane by image processing. In this method, chitin was indirectly quantified using chitosan–I₃^? complex, which exhibited a specific red-purple color. A calibration curve using a chitosan solution showed good linearity in a concentration range of 0.05–0.5 μg/μL. We quantified the amount of chitin in peritrophic membrane of Spodoptera litura (Lepidoptera: Noctuidae) larvae using this method. Throughout the study, only common inexpensive regents and easily attainable apparatuses were employed. This method can be easily applied to the sensitive quantification of the amounts of chitin and chitosan in materials by wide range of researchers.

Abbreviations: LOD: limit of detection; LOQ: limit of quantification; ROI: region of interest; RSD: relative standard deviation.     

Histopathological indices and inflammatory response in the digestive gland of the mussel Mytilus galloprovincialis as biomarker of immunotoxicity to silver nanoparticles

Background: Histopathological assessments approaches in bivalves have become an important tool in environmental toxicology. This study seeks to develop a quantitative histopathological index (Ih) and inflammation score as biomarkers in the aim to assess the health status of nanoparticles exposed mussels.

Methods: Digestive gland hematoxylin and eosin (H&;E) stained sections from Mytilus galloprovincialis were assessed after in vivo exposure (for 3, 6 and 12?h) to silver nanoparticles (Ag-NPs?Results: Silver nanoparticles clearly induced histopathological alterations in digestive gland (maximum inflammation 2.75 with AgNP?p?Ih with AgNP?p?Ih were recorded after uptake routes were blockade: AgNP?p?Conclusions: Histopathological assessments showed to be promising tool in nanotoxicity which seems to depend on nanoparticles size, exposure time and interestingly to uptake routes. It was not clear: is it the length of exposure or the size of particles is more impactful.     

Fate of mercury in a terrestrial biological lab process using Polypogon monspeliensis and Cyperus odoratus

Abstract

Mercury has been extracted in Queretaro, Mexico since the 1960s. The mining wastes were open-air disposal and these mercury wastes have polluted the zone. The aim of this research was to evaluate mercury's fate in lab scale terrestrial reactors considering the following mercury species: soluble, interchangeable, strongly bound, organic, and residual ones. Soils were sampled in two former mines of Pinal de Amoles, Queretaro, Mexico (N 20° 58′ to 21° 21′ and West 99° 26′ to 99° 43′) with initial mercury concentrations were 424?±?29 and 433?±?12?mg?kg^?1 for “La Lorena” and “San Jose” former mines, respectively. Two vegetal species Polypogon monspeliensis and Cyperus odoratus were used and 20 reactors were constructed for the lab process. Total mercury was removed to 49–79% from both soils. Mercury elemental, exchangeable, and organic species had the most removal or exchange in the process. Metal uptake, by the plants, was of 5–6% for P. monspeliensis and 5–15% for C. odoratus. Also, mercury fate was estimated to the atmosphere to be 3.3–4.5?mg m^?2 h^?1 for both soils.     

Determination of S-phenylmercapturic acid by GC-MS and ELISA: a comparison of the two methods

Abstract

S-phenylmercapturic acid (PMA) is a specific urinary biomarker of benzene at exposure levels lower than 1?ppm. However, measuring PMA in urine is an expensive task by either GC or HPLC due to the necessity of extensive sample pretreatment. In the present study, a commercial chemiluminescence enzyme-linked immunosorbent assay (ELISA) test for PMA and GC-MS were used for screening urine samples of 60 workers employed in petrochemical settings. The ELISA results were evaluated by comparison with the GC-MS. Overall, the ELISA test proved sensitive (limit of detection?=?0.1?µg?l^?1), rapid, robust and reliable, affording results in good agreement with the GC-MS (54% of measurements) and no false-negatives. On the other hand, 46% of the ELISA assays were assigned as false-positives (arbitrarily established when ELISA >5?µg?l^?1, GC-MS <5?µg?l^?1) and a correlation coefficient of 0.687 was calculated between the two methods. It appears that urinary PMA routine biomonitoring on large numbers of samples is carried out in a cost-effective and rapid approach by preliminary screening with the ELISA assay followed by GC-MS confirmation of concentrations exceeding the biological exposure index for PMA.     

Influence of stress factors on growth and pigment production in three Dunaliella species cultivated outdoors in flat-plate photobioreactors

Abstract

Growth and production of carotenoid in three Dunaliella species (Dunaliella salina (Dunal) Teodoresco, Dunaliella bardawil Ben-Amotz & Avron and Dunaliella sp.) were investigated using flat-plate photobioreactors in outdoor conditions with two optical paths (3?cm and 5?cm). The experiment was conducted in duplicate and lasted four weeks during which light intensity, temperature, pH and optical density were checked daily. The pigment production (total carotenoid and chlorophyll a) was monitored every two days. To induce an additional stress besides temperature and light intensity, two different salt concentrations were used, i.e. 6% and 8% NaCl. The highest growth in all treatment groups was noticed for Dunaliella sp. followed by D. bardawil and D. salina. D. salina produced a higher content of carotenoid concentrations corresponding to 5?cm/8% and 5?cm/6% groups; 779.102?±?0.434?μg.mL^?1 and 694.326?±?0.098?μg.mL^?1 were registered at the end of the experiment. The same species had also greater content of β-carotene.