Bovine serum albumin (BSA) nonspecifically binds to well-dispersed multiwalled carbon nanotubes (MWCNTs), forming a stable bioconjugate. After accounting for the inner filter effect, we found the fluorescence intensity of BSA was quenched by MWCNTs in static mode, which was authenticated by lifetime measurements and Stern-Volmer calculations. The thermodynamic parameters DeltaG(o), DeltaS(o), and DeltaH(o) were -9.67 x 10(3) + 2.48 x 10(3) ln lambda J x mol(-1), 41.0 - 0.828 ln lambda J x mol(-1) x K(-1), and 7.30 x 10(3) + 2.23 x 10(3) ln lambda J x mol(-1) (lambda < 1 x 10(-4)), respectively, which shows a spontaneous and electrostatic interaction. Scatchard analysis and UV-visible results provide statistical data concerning changes in the microenvironment of amide moieties in response to different doses of MWCNTs, revealing different behavior of the BSA molecules. The absorption spectra also show that the tertiary structure of the protein was partially destroyed. The content of secondary structure elements of BSA was changed by the tubes. This work elucidates the interaction mechanism of BSA and MWCNTs from a spectroscopic angle.

Tartrazine is an artificial azo dye commonly used in food products. The present study evaluated the interaction of tartrazine with two serum albumins (SAs), human serum albumin (HSA) and bovine serum albumin (BSA), under physiological conditions by means of fluorescence, three-dimensional fluorescence, UV-vis absorption, and circular dichroism (CD) techniques. The fluorescence data showed that tartrazine could bind to the two SAs to form a complex. The binding process was a spontaneous molecular interaction procedure, in which van der Waals and hydrogen bond interactions played a major role. Additionally, as shown by the UV-vis absorption, three-dimensional fluorescence, and CD results, tartrazine could lead to conformational and some microenvironmental changes of both SAs, which may affect the physiological functions of SAs. The work provides important insight into the mechanism of toxicity of tartrazine in vivo.

Perfluoroalkyl acids (PFAAs), an emerging class of globally environmental contaminants, pose a great threat to humans with wide exposure from food and other potential sources. To evaluate the toxicity of PFAAs at the protein level, the effects of three PFAAs on bovine serum albumin (BSA) were characterized by fluorescence spectroscopy, synchronous fluorescence spectroscopy, and circular dichroism (CD). On the basis of the fluorescence spectra and CD data, we concluded that perfluoropentanoic acid (PFPA) had little effect on BSA. However, perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) exhibited remarkable fluorescence quenching, which was attributed to the formation of a moderately strong complex. The enthalpy change (DeltaH) and entropy change (DeltaS) indicated that van der Waals forces and hydrogen bonds were the dominant intermolecular forces in the binding of PFAAs to BSA. Furthermore, the BSA conformation was slightly altered in the presence of PFOA and PFDA, with a reduction of alpha helix. These results indicated that PFAAs indeed impact the conformation of BSA, and PFAAs with longer carbon chains were more toxic, especially at lower concentrations.

Although initial studies suggested that Denisovan ancestry was found only in modern human populations from island Southeast Asia and Oceania, more recent studies have suggested that Denisovan ancestry may be more widespread. However, the geographic extent of Denisovan ancestry has not been determined, and moreover the relationship between the Denisovan ancestry in Oceania and that elsewhere has not been studied. Here we analyze genome-wide single nucleotide polymorphism data from 2,493 individuals from 221 worldwide populations, and show that there is a widespread signal of a very low level of Denisovan ancestry across Eastern Eurasian and Native American (EE/NA) populations. We also verify a higher level of Denisovan ancestry in Oceania than that in EE/NA; the Denisovan ancestry in Oceania is correlated with the amount of New Guinea ancestry, but not the amount of Australian ancestry, indicating that recent gene flow from New Guinea likely accounts for signals of Denisovan ancestry across Oceania. However, Denisovan ancestry in EE/NA populations is equally correlated with their New Guinea or their Australian ancestry, suggesting a common source for the Denisovan ancestry in EE/NA and Oceanian populations. Our results suggest that Denisovan ancestry in EE/NA is derived either from common ancestry with, or gene flow from, the common ancestor of New Guineans and Australians, indicating a more complex history involving East Eurasians and Oceanians than previously suspected.

This study compared the effects of sodium selenite and selenium yeast and their combination on laying performance, egg quality, antioxidant capacity, and selenium (Se) contents in tissues and eggs. Two-hundred-eighty-eight Jing Hong layers that were similar in laying rate (87.5 ± 0.38%) and body weight (1.70 ± 0.02 kg) were randomly distributed into 4 treatments for 11 wk (from 203 d old to 279 d old) with 9 replicates of 8 hens per replicate. The diets (corn-soybean meal diet) were supplemented with 0 [blank control (BC)], 0.3 mg/kg Se from sodium selenite (SS), 0.15 mg/kg Se from sodium selenite and 0.15 mg/kg Se from Se yeast (SS+SY), or 0.3 mg/kg Se from Se yeast (SY). Results showed that the laying rate of the SS+SY group increased significantly (P < 0.05) compared to the BC and SY groups. There were no differences (P > 0.05) in egg quality between the Se-supplemented diets and the BC diet. The serum glutathione peroxidase (GSH-Px) activity was increased (P < 0.01) in hens fed Se-supplemented diets compared to the BC diet. The liver superoxide dismutase (SOD) activity of the SY group was increased significantly (P < 0.05) compared to the BC group. Significant increase (P < 0.01) due to SY supplementation was noted in the serum vitamin E content compared to BC and SS. Layers fed Se-supplemented diets had higher (P < 0.01) contents of Se in the serum, liver, and kidney compared to the BC diet. Compared to BC, Se content in eggs was significantly increased (P < 0.05) by feeding supplementary Se. In conclusion, the effects of SS and Se yeast were approximately equal in promoting antioxidant capacity of laying hens, while Se yeast is easier to deposit into eggs and tissues. The diet with added equal amounts of the 2 sources of Se was more cost effective and affordable than a comparable amount of Se yeast to obtain the promising production performance and nearly similar Se deposition.