Increased ��-tocotrienol content in seeds of transgenic rice overexpressing Arabidopsis ��-tocopherol methyltransferase

Vitamin E comprises a group of eight lipid soluble antioxidant compounds that are an essential part of the human diet. The ??-isomers of both tocopherol and tocotrienol are generally considered to have the highest antioxidant activities. ??-tocopherol methyltransferase (??-TMT) catalyzes the final step in vitamin E biosynthesis, the methylation of ??- and ??-isomers to ??- and ??-isomers. In present study, the Arabidopsis ??-TMT (AtTMT) cDNA was overexpressed constitutively or in the endosperm of the elite japonica rice cultivar Wuyujing 3 (WY3) by Agrobacterium-mediated transformation. HPLC analysis showed that, in brown rice of the wild type or transgenic controls with empty vector, the ??-/??-tocotrienol ratio was only 0.7, much lower than that for tocopherol (~19.0). In transgenic rice overexpressing AtTMT driven by the constitutive Ubi promoter, most of the ??-isomers were converted to ??-isomers, especially the ??- and ??-tocotrienol levels were dramatically decreased. As a result, the ??-tocotrienol content was greatly increased in the transgenic seeds. Similarly, over-expression of AtTMT in the endosperm also resulted in an increase in the ??-tocotrienol content. The results showed that the ??-/??-tocopherol ratio also increased in the transgenic seeds, but there was no significant effect on ??-tocopherol level, which may reflect the fact that ??-tocopherol is present in very small amounts in wild type rice seeds. AtTMT overexpression had no effect on the absolute total content of either tocopherols or tocotrienols. Taken together, these results are the first demonstration that the overexpression of a foreign ??-TMT significantly shift the tocotrienol synthesis in rice, which is one of the world??s most important food crops.     

Effect of UV-B radiation on the synthesis of UV-absorbing compounds in a terrestrial cyanobacterium, Nostoc flagelliforme

Effects of two intensities (1 and 5 W?m^?2) of UV-B radiation on the synthesis of UV-absorbing compounds in a terrestrial cyanobacterium Nostoc flagelliforme were investigated. UV-B radiation resulted in lower biomass. Short period (less than 12 h) of UV-B radiation caused an increase of chlorophyll a content, but subsequent duration of treatment (more than 24 h) resulted in a rapid decrease. N. flagelliforme synthesized UV-absorbing compounds such as scytonemin and mycosporine-like amino acids (MAAs) in response to UV-B radiation. Upon 48 h of exposure to UV-B radiation, scytonemin content in cells increased by 103.8 and 164.0 % at 1 and 5 W?m^?2, respectively. Oligosaccharide-linked mycosporine-like amino acids increased by 145.5 % after 12 h at 5 W?m^?2 and 114.5 % after 48 h at 1 W?m^?2 UV-B radiation. HPLC analysis showed that nine MAAs existed in N. flagelliforme cells both from liquid suspension culture and field colony. But the concentration and kinds of them were different. At the two distinct levels of UV-B radiation, the content of particular MAAs increased, declined, or remained unchanged. Moreover, the appearance of two new MAAs was observed.     

Effects of dietary L-carnitine and coenzyme Q10 supplementation on performance and ascites mortality of broilers

The study was conducted to determine the effects of dietary L-carnitine and coenzyme Q₁₀ (CoQ₁₀) supplementation on growth performance and ascites mortality of broilers. A 3 × 3 factorial arrangement was employed with three levels (0, 75 and 150 mg/kg) of L-carnitine and three levels of CoQ₁₀ (0, 20 and 40 mg/kg) supplementation during the experiment. Five hundred and forty one-day-old Arbor Acre male broiler chicks were randomly allocated into nine groups with six replicates each. All birds were fed with the basal diets from day 1 to 7 and changed to the experimental diets from day 8. During day 15 to 21 all the birds were exposed to low ambient temperature (15 - 18°C) to induce ascites. The results showed that under this condition, growth performance of broilers were not significantly affected by CoQ₁₀ or L-carnitine + CoQ₁₀ supplementation during week 0 - 3 and 0 - 6, but body weight gain (BWG) of broilers was significantly reduced by 150 mg/kg L-carnitine during week 0 - 6. Packed cell volume (PCV) of broilers was significantly decreased by L-carnitine and L-carnitine + CoQ₁₀ supplementation (P < 0.05). Erythrocyte osmotic fragility (EOF), ascites heart index (AHI) and ascites mortality of broilers were significantly decreased by L-carnitine, CoQ₁₀ and L-carnitine + CoQ₁₀ supplementation. Though no significant changes were observed in total antioxidative capability (T-AOC), total superoxide dismutase (T-SOD) was increased by L-carnitine, CoQ₁₀ and L-carnitine + CoQ₁₀ supplementation (P < 0.05). Malonaldehyde (MDA) content was significantly decreased by CoQ₁₀ and L-carnitine + CoQ₁₀ supplementation. The results indicate that dietary L-carnitine and CoQ₁₀ supplementation reduce ascites mortality of broilers; the reason may be partially associated with their antioxidative effects.     

Stress-Derived Corticotropin Releasing Factor Breaches Epithelial Endotoxin Tolerance

Background and aims

Loss of the endotoxin tolerance of intestinal epithelium contributes to a number of intestinal diseases. The etiology is not clear. Psychological stress is proposed to compromise the intestinal barrier function. The present study aims to elucidate the role of the stress-derived corticotropin releasing factor (CRF) in breaching the established intestinal epithelial endotoxin tolerance.

Methods

Epithelial cells of HT-29, T84 and MDCK were exposed to lipopolysaccharide to induce the endotoxin tolerance; the cells were then stimulated with CRF. The epithelial barrier function was determined using as indicators of the endotoxin tolerant status. A water-avoid stress mouse model was employed to test the role of CRF in breaching the established endotoxin tolerance in the intestine.

Results

The established endotoxin tolerance in the epithelial cell monolayers was broken down by a sequent exposure to CRF and LPS manifesting a marked drop of the transepithelial resistance (TER) and an increase in the permeability to a macromolecular tracer, horseradish peroxidase (HRP). The exposure to CRF also increased the expression of Cldn2 in the epithelial cells, which could be mimicked by over expression of TLR4 in epithelial cells. Over expression of Cldn2 resulted in low TER in epithelial monolayers and high permeability to HRP. After treating mice with the 10-day chronic stress, the intestinal epithelial barrier function was markedly compromised, which could be prevented by blocking either CRF, or TLR4, or Cldn2.

Conclusions

Psychological stress-derived CRF can breach the established endotoxin tolerance in the intestinal mucosa.     

Looking Time Predicts Choice but Not Aesthetic Value

Although visual fixations are commonly used to index stimulus-driven or internally-determined preference, recent evidence suggests that visual fixations can also be a source of decisional bias that moves selection toward the fixated object. These contrasting results raise the question of whether visual fixations always index comparative processes during choice-based tasks, or whether they might better reflect internal preferences when the decision does not carry any economic or corporeal consequences. In two experiments, participants chose which of two objects were more aesthetically pleasing (Exp.1) or appeared more organic (Exp.2), and provided independent aesthetic ratings of the stimuli. Our results demonstrated that fixation parameters were a better index of choice in both decisional domains than of aesthetic preference. The data support models in which visual fixations are specifically related to the evolution of decision processes even when the decision has no tangible consequences.     

The protonated 2-halogenated imidazolium cation as the noncovalent interaction donor: the σ-hole and π-hole interactions

The σ-hole and π-hole of the protonated 2-halogenated imidazolium cation (XC₃H₄N₂ ⁺; X = F, Cl, Br, I) were investigated and analyzed. The monomers of (CH₃)₃SiY(Y=F, Cl, Br, I), considered as the Lewis base, were combined with the σ-hole and π-hole of XC₃H₄N₂ ⁺ to form the σ-hole and π-hole interactions in the bimolecular complexes (CH₃)₃SiY?·?·?·?XC₃H₄N₂ ⁺ and (CH₃)₃SiY?·?·?·?C₃(X)H₄N₂ ⁺(X/Y=F, Cl, Br, I), respectively. For both the σ-hole and π-hole interactions, the equilibrium geometries of complexes show regular changes according to the sequence of heavy sequence of the noncovalent interaction acceptors and donors. The electrostatic energy is the main contribution in the formation of both kinds of interactions, it has linear relations with the V _S,max values of σ-hole and the V′ _S,max values of π-hole. Both the σ-hole and π-hole interactions belong to the closed-shell and noncovalent interactions. The π-hole interactions are stronger than the σ-hole interactions. For the π-hole interactions, the contribution percents of the dispersion energies are somewhat greater than those of the σ-hole interactions, while it is contrary for the polarization energy.

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Graphical Abstract The protonated 2-halogenated imidazolium cation as the noncovalent interaction donor: the σ-hole and π-hole interactions?