Hydrogen sulfide treatment increases the antioxidant capacity of fresh Lingwu Long Jujube (Ziziphus jujuba cv. Mill) fruit during storage.

Hydrogen sulfide (H2S) has been identified as an important gaseous signal molecule in plants. Here, we investigated the effects of H2S on postharvest senescence and antioxidant metabolism of Lingwu Long Jujube (Ziziphus jujuba cv. Mill) fruits (LLJF). Fumigation of Jujube fruits with H2S released from 0.4 mm NaHS could significantly prolong the postharvest shelf life of jujube fruits, reduce the decay rate of fruit, the weight loss of fruit, and inhibit the fruit loss, hardness, color, soluble solids, and titratable acidity. Compared with the control group, exogenous H2S fumigation significantly decreased the loss of chlorophyll, carotenoids, soluble protein, ascorbic acid, phenols, and flavonoids in jujube fruits during post-harvest storage. At the same time, H2S could significantly delay the accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2 ∙-) and promote catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD) activity, and inhibit polyphenol oxidase (PPO) activity. To summarize, H2S can effectively alleviate postharvest senescence and decay of jujube fruits by regulating the ROS accumulation and antioxidant enzymes, and prolong the storage period of postharvest.

Interaction between the Non-Fullerene Acceptor ITIC and Potassium.

Using density functional theory calculations and photoemission measurements, we have studied the interaction between the non-fullerene small-molecule acceptor ITIC and K atoms (a representative of reactive metals). It is found that the acceptor-donor-acceptor-type geometric structure and the electronic structure of ITIC largely decide the interaction process. One ITIC molecule can combine with more than 20 K atoms. For stoichiometries K x≤6ITIC, the K atoms are attracted to the acceptor units of the molecule and donate their 4s electrons to the unoccupied molecular orbitals. K-ITIC organometallic complexes, characterized by the breaking of some S-C bonds in the donor unit of ITIC and the formation of K-S bonds, are formed for stoichiometries K x≥7ITIC. The complexes are still conjugated despite the breaking of some S-C bonds.

Electronic states of a C70 monolayer on the surface of Ag(111).

We have investigated the electronic states of a C(70) monolayer on the surface of Ag(111) (1 ML C(70)/Ag(111)) using synchrotron radiation photoelectron spectroscopy and soft x-ray absorption spectroscopy techniques. The experimental data exhibit metallic properties and at least 2.6 e(-) charge transfer per C(70) molecule. The screening effect of Ag(111) on the electronic structure of C(70) is remarkable; it greatly reduces or even eliminates the on-site Hubbard energy. The work functions of the C(70) multilayer and monolayer are determined as 4.53 eV and 4.52 eV respectively. The energy levels of C(70) align with the Fermi level of the Ag(111) substrate, and the shift of the vacuum level caused by C(70) adsorption is negligible. Potassium doping indicates that 1 ML C(70)/Ag(111) can still accommodate about nine electrons and that the sample remains metallic at any doping level.

Electronic structure of Eu-C(70) fullerides.

The electronic structure of Eu-intercalated C(70) has been studied by a synchrotron radiation photoemission spectroscopy technique. At low intercalation levels (below the stoichiometry of Eu(3)C(70)), the photoemission data clearly exhibit charge transfer from Eu 6s states to the lowest-unoccupied-molecular-orbital (LUMO) and the LUMO + 1 of C(70). The amount of charge transfer reaches its maximum far before intercalation saturation. Detailed analysis reveals that most of the 5d6s electrons of Eu occupy the so-called interstitial states in the saturation phase (Eu(9)C(70)). The interstitial states are induced by a Eu sub-lattice formed at heavy intercalation levels, and comprise substantial 6s-π hybridized states. The π states participating in the hybridization are mainly the HOMO - n (n = 6-10) orbitals. The PES data also reveal the semiconducting property for both Eu(3)C(70) and Eu(9)C(70). The 6s-(HOMO - n) hybridization and the semiconducting property should play important roles in understanding the ferromagnetic mechanism for Eu(9)C(70).

Electronic structure of C(84) film studied by photoemission measurement and first-principles calculation.

We have measured the photoemission spectra of a C(84) film (isomer mixture) with synchrotron radiation. The valence band exhibits abundant spectral features from the Fermi level to ∼18 eV binding energy. The relative intensity between the lowest binding energy feature (labeled as A) and the next lowest binding energy feature (labeled as B) oscillates distinctly within the experimental photon energy region from 21.0 to 63.0 eV. The energy levels and density of states (DOS) are calculated for the D(2d)(23)- C(84) and four D(2) symmetric (D(2)(1), D(2)(5), D(2)(21) and D(2)(22)) C(84) isomers to help us to understand the electronic structure. The experimental features and the theoretical DOS peaks have one-to-one correspondence. The number of electrons occupying the states of feature A is 12 or 13.3, depending on the different kinds of isomer mixtures. The electron occupation of feature B is 18.67 e. With the spherical symmetric approximation, features A and B can be characterized with angular momenta of 6 and 5, respectively. The angular momentum difference is the reason for the photoelectron intensity oscillations.

Monitoring microarray-based gene expression profile changes in hepatocellular carcinoma.

AIM: To find out key genes responsible for hepatocarcinogenesis and to further understand the underlying molecular mechanism through investigating the differential gene expression between human normal liver tissue and hepatocellular carcinoma (HCC). METHODS: DNA microarray was prepared by spotting PCR products of 1 000 human genes including 445 novel genes, 540 known genes as well as 12 positive (housekeeping) and 3 negative controls (plant gene) onto treated glass slides. cDNA probes were prepared by labeling normal liver tissue mRNA and cancer liver tissue mRNA with Cy3-dUTP and Cy5-dUTP separately through reverse transcription. The arrays were hybridized against the cDNA probe and the fluorescent signals were scanned. The data obtained from repeated experiments were analyzed. RESULTS: Among the 20 couple samples investigated (from cancerous liver tissue and normal liver tissue), 38 genes including 21 novel genes and 17 known genes exhibited different expressions. CONCLUSION: cDNA microarray technique is powerful to identify candidate target genes that may play important roles in human carcinogenesis. Further analysis of the obtained genes is helpful to understand the molecular changes in HCC progression and ultimately may lead to the identification of new targets for HCC diagnosis and intervention.