The genomes of medicinal skullcaps reveal the polyphyletic origins of clerodane diterpene biosynthesis in the family Lamiaceae.

The presence of anticancer clerodane diterpenoids is a chemotaxonomic marker for the traditional Chinese medicinal plant Scutellaria barbata, although the molecular mechanisms behind clerodane biosynthesis are unknown. Here, we report a high-quality assembly of the 414.98 Mb genome of S. barbata into 13 pseudochromosomes. Using phylogenomic and biochemical data, we mapped the plastidial metabolism of kaurene (gibberellins), abietane, and clerodane diterpenes in three species of the family Lamiaceae (Scutellaria barbata, Scutellaria baicalensis, and Salvia splendens), facilitating the identification of genes involved in the biosynthesis of the clerodanes, kolavenol, and isokolavenol. We show that clerodane biosynthesis evolved through recruitment and neofunctionalization of genes from gibberellin and abietane metabolism. Despite the assumed monophyletic origin of clerodane biosynthesis, which is widespread in species of the Lamiaceae, our data show distinct evolutionary lineages and suggest polyphyletic origins of clerodane biosynthesis in the family Lamiaceae. Our study not only provides significant insights into the evolution of clerodane biosynthetic pathways in the mint family, Lamiaceae, but also will facilitate the production of anticancer clerodanes through future metabolic engineering efforts.

Solvent-Free Synthesis of Magnetic Sewage Sludge-Derived Biochar for Heavy Metal Removal from Wastewater.

The commonly used two-step and one-pot synthesis methods for producing biochar require the use of iron salt solutions, resulting in the undesirable consequences of energy consumption for dewatering and potential pollution risks. To address this drawback, a magnetic sewage sludge-derived biochar (MSBC-2) was synthesized by a solvent-free method in this study. The pseudo-second-order kinetic model and Langmuir model provided the best fit to the experimental data, implying a monolayered chemisorption process of Pb2+, Cd2+and Cu2+ onto MSBC-2. As the reaction temperature increased from 25 °C to 45 °C, the maximum adsorption capacities increased from 113.64 mg·g−1 to 151.52 mg·g−1 for Pb2+, from 101.01 mg·g−1 to 109.89 mg·g−1 for Cd2+ and from 57.80 mg·g−1 to 74.07 mg·g−1 for Cu2+, respectively. Thermodynamic parameters (ΔG0 < 0, ΔS0 > 0, ΔH0 > 0) revealed that the adsorption processes of all three metals by MSBC-2 were favourable, spontaneous and endothermic. Surface complexation, cation-π interaction, ion exchange and electrostatic attraction mechanisms were involved in the adsorption of Pb2+, Cd2+ and Cu2+ onto MSBC-2. Overall, this study will provide a new perspective for the synthesis of magnetic biochar and MSBC-2 shows great potential as an adsorbent for heavy metal removal.

Adiposity and Serum Selenium in U.S. Adults.

Requirements for selenium and other antioxidant nutrients are increased in pro-oxidant and pro-inflammatory conditions such as excess adiposity. Data concerning the association of excess general and central adiposity with circulating selenium concentrations, however, are limited. We examined the cross-sectional associations of body mass index (BMI), percent body fat (%BF), and waist circumference (WC) with serum selenium concentrations in 6440 men and 6849 women aged ≥20 years who participated in the U.S. Third National Health and Nutrition Examination Survey. In multivariable analyses, the average difference (95% confidence interval (CI)) in serum selenium comparing the highest with the lowest quartiles of BMI was -4.0 (-5.5, -1.6) ng/mL in both men and women. These inverse associations were evident after further adjustment for WC. For %BF, the average differences (95% CI) in serum selenium between the highest and the lowest quartiles of %BF were -1.7 (-4.2, 0.7) ng/mL in men and -4.5 (-7.0, -1.9) ng/mL in women. The inverse association in women persisted after adjusting for WC. For WC, the average differences (95% CI) in serum selenium between the highest and the lowest quartiles were -1.9 (-3.8, -0.1) ng/mL in men and -3.9 (-5.8, -2.0) ng/mL in women. After further adjustment for BMI, the inverse association became positive in men and null in women. Our findings suggest that general and central adiposity have different associations with serum selenium levels and that these associations may depend on gender.