Determination of selenium in red blood cells by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion

Transcriptomic signature of high dietary organic selenium supplementation in sheep: A nutrigenomic insight using a custom microarray platform and gene set enrichment analysis

The objective of this study was to investigate the effect of a high dietary Se supplementation on the whole transcriptome of sheep. A custom sheep whole-transcriptome microarray, with more than 23,000 unique transcripts, was designed and then used to profile the global gene expression of sheep after feeding a high dietary supplementation of organic Se. Lactating crossbred ewes ( = 10; 3 to 4 yr of age and 55 to 65 kg BW) at late lactation (100 ± 8 d in milk) were acclimated to indoor individual pen feeding of a basal control diet (0.40 mg Se/d, sodium selenite) for 4 wk. Sheep were then kept on a diet with an extra (high) supplementation of organic Se (1.45 mg Se/d as Sel-Plex; Alltech Biotechnology Pty Ltd, Dandenong, Victoria, Australia) for 40 d. Whole blood was collected at 2 time points (last day of the acclimatization period [T0] and after 40 d of the organic Se supplementation [T40]), and then total RNA was isolated and labeled for the subsequent microarray analysis. Significance Analysis of Microarrays, using the -statistic, of the microarray data (T40 versus T0) evidenced the up- and downregulation of 942 and 244 transcripts (false discovery rate < 0.05), respectively. Seven genes showed the same trend of expression (up- or downregulation) when tested by quantitative real-time PCR (qPCR) in a cross-validation step. The microarray showed significant upregulation of the following selenoproteins at T40: selenium binding protein 1 (SELENBP1), selenoprotein W1 (SEPW1), glutathione peroxidase 3 (GPX3), and septin 8 (SEPT8). And the expression trends for SEPW1 and SEPT8 were validated using qPCR. Functional annotation of the differentially expressed genes showed the enrichment of several immune system-related biological processes (lymphocyte activation, cytokine binding, leukocyte activation, T cell differentiation, and B cell activation) and pathways (cytokine and interleukin signaling). Moreover, Gene Set Enrichment Analysis evidenced the enrichment of B and T cell receptors signaling pathways, with an enrichment score of 0.63 and 0.59, respectively. Overall, from a global gene expression (whole-transcriptome) point of view, short-term supplementation of a high dietary organic Se to Se-nondeficient sheep results in a transcriptomic signature that mainly reflects an induced immune system and a modulation of transcription effect. Also, the present study provides a custom whole-transcriptome microarray platform that can be used in further global gene expression studies in the ovine species.

Levels of arsenic, cadmium, lead and mercury in the branchial plate and muscle tissue of mobulid rays

Mobulid rays are targeted in fisheries for their branchial plates, for use in Chinese medicine. Branchial plate and muscle tissue from Mobula japanica were collected from fish markets in Sri Lanka, and muscle tissue biopsies from Manta alfredi in Australia. These were analysed for arsenic, cadmium, lead and mercury and compared to maximum levels (MLs) set by Food Standards Australia and New Zealand (FSANZ), European Commission (EC) and Codex Alimentarius Commission. The estimated intake for a vulnerable human age group was compared to minimal risk levels set by the Agency for Toxic Substances and Disease Registry. The mean inorganic arsenic concentration in M. japanica muscle was equivalent to the FSANZ ML while cadmium exceeded the EC ML. The mean concentration of lead in M. alfredi muscle tissue exceeded EC and Codex MLs. There were significant positive linear correlations between branchial plate and muscle tissue concentrations for arsenic, cadmium and lead.

Accumulation of trace metals in the embryos and hatchlings of Chelonia mydas from Peninsular Malaysia incubated at different temperatures

A variety of trace metals were measured in the egg contents of three clutches of Chelonia mydas collected from Kuala Terengganu state in Peninsular Malaysia. We quantified Mn, Cu, Zn, Se (essential trace metals) and As (anthropogenic pollutant) at several developmental stages obtained by incubating eggs at two different temperatures (27 °C and 31 °C). The incubation temperatures were chosen because they produce predominantly male or predominantly female hatchlings, respectively. The eggs were removed from the sand and washed before being placed in incubators, to ensure that the only possible source of the detected metals was maternal transfer. Other metals: Mo, Co, Ni, Cd, Sn, Sb, Hg, Tl and Pb (all non-essential metals) were detected at concentrations below the lower limit of quantitation (LLOQ). Trace metal concentrations, particularly [Zn], increased during development, other metals (Cu, As, Se and Cr) accumulated to a lesser degree than zinc but no significant differences were observed between the incubation temperatures at any stage of incubation. To date, only a few studies on trace metals in turtle embryos and hatchlings have been reported; this study will provide basic knowledge on the accumulation of trace metals during development at two different incubation temperatures.

Hair analysis in health assessment

BACKGROUND

Hair analysis is used for estimation of the nutritional status of individuals. In the present work, a systematic review on the relation between the mineral composition of hair and the physical or mental disorders is discussed. Detailed information of examined populations, methods of sample preparations and analytical techniques are presented.

METHODS

A systematic literature search in four electronic databases Scopus, PubMed, Web of Science and Medline (from 1997 to 2012/01/31) for English language articles was performed. In addition, a reference list and manual search was undertaken.

RESULTS

The following number of studies was included: 66. Most of the authors reported that there exists a correlation between deficiency or excess of some elements in hair and occurrence of some diseases, such as: autism, cancer, hypertension, myocardial infarction, kidney disease and diabetes mellitus. However, not all results were consistent.

CONCLUSIONS

Most of the authors concluded that the profile of hair mineral imbalance might be useful as a diagnostic tool for the early diagnosis of many diseases. However, it seems that there is a need to standardize sample preparation procedures, in particular washing and mineralization methods.

Collision/reaction cell ICP-MS with shielded torch and sector field ICP-MS for the simultaneous determination of selenium isotopes in biological matrices

The determinations of selenium isotopes in biological samples were performed using both inductively coupled plasma collision/reaction cell quadruple mass spectrometer (CRC-ICP-QMS) and inductively coupled plasma sector field mass spectrometers (SF-ICP-MS). To significantly decrease the argon-based interferences at m/z 74 ((36)Ar(38)Ar), 76 ((38)Ar(38)Ar, (40)Ar(36)Ar), 78 ((38)Ar(40)Ar), and 80 ((40)Ar(40)Ar), the gas-flow rates of a helium and hydrogen mixture used in the collision cell were optimized to 1.0 mL/min H(2) and 3.5 mL/min He. Under the optimized condition, the precisions for natural selenium isotope ratio measurements of both instruments were evaluated and compared using 100 ppb Se standard solution. A modified external calibration quantification method was applied for the simultaneous determination of clinically used enriched selinocompounds ((77)Se-selenate, (82)Se-selenite, (76)Se-methylseleninic acid(IV), (78)Se-methylselenonic acid(VI)) and to examine their fate in rat organs (liver, kidney, and lung).

Trace element concentrations in nesting flatback turtles (Natator depressus) from Curtis Island, Queensland, Australia

The blood and eggs of the flatback turtle (Natator depressus) sampled when nesting at Curtis Island, Queensland, Australia. In the blood, zinc was present at the highest concentration of 151.15 ± 1.45 μg/L followed by copper (7.74 ± 0.09 μg/L). Lead was found only in some individuals. The measured trace elements in the blood were maternally transferred into the eggs. Other metals and metalloids detected in eggs were chromium, manganese, arsenic and selenium. Eggs showed a more complex trace element profile than blood, suggesting that they provided more representative tissues for determining maternal levels of trace element accumulation in N. depressus. Intra-clutch variation was over 15% for most of the studied trace elements suggesting one egg is not in sufficient to determine trace element accumulation within a clutch. Copper was the only element which was positively correlated with breeding age. Furthermore, no detectable levels of tin compound derivates were measured in N. depressus.

Using blood samples to estimate persistent organic pollutants and metals in green sea turtles (Chelonia mydas)

Persistent organic pollutants (POPs) and heavy metals have been reported in a number of green turtle (Chelonia mydas) populations worldwide. However, due to ethical considerations, these studies have generally been on tissues from deceased and stranded animals. The purpose of this study was to investigate the use of blood samples to estimate the tissue contamination of live C. mydas populations. This study analysed 125 POP compounds and eight heavy metals in the blood, liver, kidney and muscle of 16 C. mydas from the Sea World Sea Turtle Rehabilitation Program, Gold Coast, Australia. Strong correlations were observed between blood and tissue concentrations for a number of POPs and metals. Furthermore, these correlations were observed over large ranges of turtle size, sex and condition. These results indicate that blood samples are a reliable non-lethal method for predicting chemical contamination in C. mydas.

Chemical contamination of green turtle (Chelonia mydas) eggs in peninsular Malaysia: implications for conservation and public health

BACKGROUND

Persistent organic pollutants (POPs)-such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs)-and heavy metals have been reported in sea turtles at various stages of their life cycle. These chemicals can disrupt development and function of wildlife. Furthermore, in areas such as Peninsular Malaysia, where the human consumption of sea turtle eggs is prevalent, egg contamination may also have public health implications.

OBJECTIVE

In the present study we investigated conservation and human health risks associated with the chemical contamination of green turtle (Chelonia mydas) eggs in Peninsular Malaysia.

METHODS

Fifty-five C. mydas eggs were collected from markets in Peninsular Malaysia and analyzed for POPs and heavy metals. We conducted screening risk assessments (SRAs) and calculated the percent of acceptable daily intake (ADI) for POPs and metals to assess conservation and human health risks associated with egg contamination.

RESULTS

C. mydas eggs were available in 9 of the 33 markets visited. These eggs came from seven nesting areas from as far away as Borneo Malaysia. SRAs indicated a significant risk to embryonic development associated with the observed arsenic concentrations. Furthermore, the concentrations of coplanar PCBs represented 3 300 times the ADI values set by the World Health Organization.

CONCLUSIONS

The concentrations of POPs and heavy metals reported in C. mydas eggs from markets in Peninsular Malaysia pose considerable risks to sea turtle conservation and human health.