Effect of dietary selenium intake on gut microbiota in older population in Enshi region

Background The microbial ecosystem in the human gut varies between individuals with differences in diet. Selenium is one of most common trace elements in everyday diet, and selenium intake affects the human gut microbiota. We studied the effect of selenium intake on the gut microbiota in regions of Enshi with different distributions of selenium. Methods One hundred elderly subjects (>65 years) were recruited from high-selenium and low-selenium areas in Enshi and blood, nail, and fecal specimens were obtained. The selenium contents in these samples were determined in triplicate by hydride generation atomic fluorescence spectrometry. DNA was extracted from fecal specimens and the microbial diversity was analyzed by 16 S RNA. Results The selenium contents in the blood and nails were significantly different between the high- and low-selenium areas, and the composition of the intestinal microbiota, including abundance and extent of intestinal flora, was altered. The function and metabolic pathways of the gut microbiota showed clear differences. Conclusions As a trace element in human diet, selenium intake is an important factor that affects the intestinal microbiota and is likely involved in many human diseases. This study provides new clues and ideas for studying the correlation between selenium and human health.

Study on the Ecological Circulation Agricultural System of Combining Planting and Raising of Berry Tea

Berry tea is a perennial vine. Its scientific name is ampelopsis grossedentata. It belongs to vitaceae and is widely spread in the Tujia people of Xiangxi, Hunan Province. By adopting appropriate agricultural planting technology, rational use of organic selenium fertilizer and nutritional conditioner, we can produce high-quality berry tea with more healthy and even medicinal value and high selenium content, and realize double protection of human health with high selenium content and high flavonoids. Under the existing planting system, through the supplement of breeding links, constructing ecological recycling agricultural system combining planting and raising, not only can greatly enrich the supply of table agricultural products, but also can effectively ensure the high quality and high safety of agricultural products, and can effectively enrich the local agricultural industrial structure.Key words: berry tea; selenium-enriched; ecological agriculture; industrial revitalization and economic development

Comparison of selenium-induced antioxidant responses and bioaccumulation in two strains of the halotolerant alga Dunaliella salina

Selenium water pollution is an increasing environmental problem that requires investigation of cellular responses of aquatic primary producer organisms, especially algae. Industrial wastewater with selenium contamination is often coupled with high salinity (60–70). In this study, the biochemical responses of two strains of the halotolerant alga (Dunaliella salina Hoze-soltan and Dunaliella salina CCAP 19/18) to different selenium concentrations were evaluated. Although at high selenium concentrations both strains showed lipid peroxidation and cell number reduction, Dunaliella salina Hoze-soltan was less affected. Higher selenium tolerance in this strain might be attributed to the better activity of resistance responses like proline, total reducing sugar, superoxide dismutase (SOD) and peroxidase (POX), even at the high selenium concentrations. Catalase (CAT) had no significant role for protection against selenium toxicity as its activity declined in both strains with rising selenium concentration. Both strains accumulated selenium intracellularly, but the accumulation was about three-fold higher in Dunaliella salina Hoze-soltan than in the other strain. It can be concluded that Dunaliella salina Hoze-soltan may be a better candidate for selenium bioremediation of a high salinity environment. The data obtained from this study could be useful for improvement of algal ability for high efficiency selenium bioremediation in hypersaline environments.

De novo Transcriptome Assembly and Comparative Analysis Highlight the Primary Mechanism Regulating the Response to Selenium Stimuli in Oats (Avena sativa L.)

Selenium is an essential microelement for humans and animals. The specific processing technique of oats can maximize the preservation of its nutrients. In this study, to understand the genetic response of oats in a high-selenium environment, oats were treated with sodium selenate for 24 h, and transcriptome analysis was performed. A total of 211,485,930 clean reads composing 31.30 Gb of clean data were retained for four samples. After assembly, 186,035 unigenes with an average length of 727 bp were generated, and the N50 length was 1,149 bp. Compared with that in the control group, the expression of 7,226 unigenes in the treatment group was upregulated, and 2,618 unigenes were downregulated. Based on the sulfur assimilation pathway and selenocompound metabolic pathway, a total of 27 unigenes related to selenate metabolism were identified. Among them, the expression of both key genes APS (ATP sulfurylase) and APR (adenosine 5′-phosphosulfate reductase) was upregulated more than 1,000-fold under selenate treatment, while that of CBL (cystathionine-β-synthase) was upregulated 3.12-fold. Based on the transcriptome analysis, we suspect that the high-affinity sulfur transporter Sultr1;2 plays a key role in selenate uptake in oats. A preliminary regulatory mechanism explains the oat response to selenate treatment was ultimately proposed based on the transcriptome analysis and previous research.

Regional Difference in the Association between the Trajectory of Selenium Intake and Hypertension: A 20-Year Cohort Study

The effect of selenium on hypertension is inconclusive. We aimed to study the relationship between selenium intake and incident hypertension. Adults (age ≥20 years) in the China Health and Nutrition Survey were followed up from 1991 to 2011 (N = 13,668). The latent class modeling method was used to identify trajectory groups of selenium intake. A total of 4039 respondents developed hypertension. The incidence of hypertension was 30.1, 30.5, 30.6, and 31.2 per 1000 person-years among participants with cumulative average selenium intake of 21.0 ± 5.1, 33.2 ± 2.8, 43.8 ± 3.6, and 68.3 ± 25.2 µg/day, respectively. Region and selenium intake interaction in relation to hypertension was significant. In the multivariable model, cumulative intake of selenium was only inversely associated with the incident hypertension in northern participants (low selenium zone), and not in southern participants. Compared to selenium intake trajectory Group 1 (stable low intake), all three trajectory groups had a low hazard ratio for hypertension among the northern participants. However, Group 4 (high intake and decreased) showed an increasing trend of hypertension risk in the south. In conclusion, the association between selenium intake and the incidence of hypertension varied according to regions in China. In the low soil selenium zone, high selenium intake might be beneficial for hypertension prevention.

Genome-Wide Identification and Expansion Patterns of SULTR Gene Family in Gramineae Crops and Their Expression Profiles under Abiotic Stress in Oryza sativa

Sulfate transporters (SULTRs), also known as H+/SO42− symporters, play a key role in sulfate transport, plant growth and stress responses. However, the evolutionary relationships and functional differentiation of SULTRs in Gramineae crops are rarely reported. Here, 111 SULTRs were retrieved from the genomes of 10 Gramineae species, including Brachypodium disachyon, Hordeum vulgare, Setaria italica, Sorghum bicolor, Zea mays, Oryza barthii, Oryza rufipogon, Oryza glabbermia and Oryza sativa (Oryza sativa ssp. indica and Oryza sativa ssp. japonica). The SULTRs were clustered into five clades based on a phylogenetic analysis. Syntheny analysis indicates that whole-genome duplication/segmental duplication and tandem duplication events were essential in the SULTRs family expansion. We further found that different clades and orthologous groups of SULTRs were under a strong purifying selective force. Expression analysis showed that rice SULTRs with high-affinity transporters are associated with the functions of sulfate uptake and transport during rice seedling development. Furthermore, using Oryza sativa ssp. indica as a model species, we found that OsiSULTR10 was significantly upregulated under salt stress, while OsiSULTR3 and OsiSULTR12 showed remarkable upregulation under high temperature, low-selenium and drought stresses. OsiSULTR3 and OsiSULTR9 were upregulated under both low-selenium and high-selenium stresses. This study illustrates the expression and evolutionary patterns of the SULTRs family in Gramineae species, which will facilitate further studies of SULTR in other Gramineae species.

The association of serum selenium with serum lipids in US adults

High selenium concentrations were associated with cardiovascular diseases, type 2 diabetes, and central nervous disorders. The author examined the relation of serum selenium concentration with serum lipids levels with the use of the National Health and Nutrition Examination Survey (NHANES) 2017-2018. 759 adults aged more than 20 years old from NHANES 2017-2018 were examined in the analysis. Serum selenium was measured by mass spectrometry. Triglyceride, HDL cholesterol, and total cholesterol were measured through enzymatical methods. LDL cholesterol was calculated then. Comparing Q4 to Q1 of serum selenium, the multivariable adjusted average differences (95% CI) in triglyceride, HDL cholesterol, LDL cholesterol, and total cholesterol were 21.3 mg/dL (9.1, 33.4 mg/dL), 2.3 mg/dL (-0.6, 5.2 mg/dL), 6.3 mg/dL (-1.3, 13.9 mg/dL), 12.8 (95% CI: 4.2, 21.5 mg/dL), respectively. Hence, The increasing serum selenium concentration is associated with increasing triglyceride, total cholesterol, HDL cholesterol, and LDL cholesterol among US adults.