New Efforts toward Aminothiazolylquinolones with Multitargeting Antibacterial Potential.

New antibacterial 3-(aminothiazolyl)quinolones (ATQs) were designed and efficiently synthesized to counteract the growing multidrug resistance in animal husbandry. Bioactive assays manifested that N,N-dicyclohexylaminocarbonyl ATQ 10e and methyl ATQ 17a, respectively, showed better antibacterial behavior against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa than reference drug norfloxacin. Notably, highly active ATQ 17a with low hemolysis, negligible mammalian cytotoxicity, and good pharmacokinetic properties displayed low trends to induce resistance and synergistic combinations with norfloxacin. Preliminary mechanism exploration implied that representative ATQ 17a could inhibit the formation of biofilms and destroy bacterial membrane integrity, further binding to intracellular DNA and DNA gyrase to hinder bacterial DNA replication. ATQ 17a could also induce the production of excess reactive oxygen species and reduce bacterial metabolism to accelerate bacterial death. These results provided a promise for 3-(aminothiazolyl)quinolones as new potential multitargeting antibacterial agents to treat bacterial infection of animals.

[Ionization energies and infrared spectra studies of histidine using density functional theory].

Histidines provide axial ligands to the primary electron donors in photosynthetic reaction centers (RCs) and play an important role in the protein environments of these donors. In this paper the authors present a systematic study of ionization energies and vibrational properties of histidine using hybrid density functional theory (DFT). All calculations were undertaken by using B3LYP method in combination with four basis sets: 6-31G(d), 6-31G(df, p), 6-31+G(d) and 6-311+G(2d, 2p) with the aim to investigate how the basis sets influence the calculation results. To investigate solvent effects and gain a detailed understanding of marker bands of histidine, the ionization energies of histidine and the vibrational frequencies of histidine which are unlabeled and 13C, 15N, and 2H labeled in the gas phase, CCl4, protein environment, THF and water solution, which span a wide range of dielectric constant, were also calculated. Our results showed that: (1) The main geometry parameters of histidine were impacted by basis sets and mediums, and C2-N3 and N3-C4 bond of imidazole ring of histidine side chain display the maximum bond lengths in the gas phase; (2) single point energies and frequencies calculated were decreased while ionization energies increased with the increasing level of basis sets and diffuse function applied in the same solvent; (3) with the same computational method, the higher the dielectric constant of the solvent used, the lower the ionization energy and vibrational frequency and the higher the intensity obtained. In addition, calculated ionization energy in the gas phase and marker bands of histidine as well as frequency shift upon 13C and 15N labeling at the computationally more expensive 6-311+G(2d, 2p) level are in good agreement with experimental observations available in literatures. All calculations indicated that the results calculated by using higher level basis set with diffuse function were more accurate and closer to the experimental value. In conclusion, the results provide useful information for the further studies of the functional and vibrational properties of chlorophyll-a ligated to histidine residue in photosynthetic reaction center.

[Investigation of Amanitaceae mushrooms by Fourier transform infrared spectroscopy].

In the present paper, FTIR was used for obtaining vibrational spectra of untreated Amanitaceae mushrooms harvested in the mountains of Yunnan province, Southwest of China. The results show that the spectra of fruiting body and spore exhibit obvious differences. In the spectra of fruiting body, the strongest absorption band appears at about 1 655 cm(-1), which is described as amide I. There are two strong absorption bands at 1 077 and 1 042 cm(-1) which are assigned to C-O stretching in carbohydrate. The vibrational spectra indicate that the main compositions of the Amanitaceae mushrooms are protein and carbohydrate. The spectrum of spore of Amanita fritillaria shows strong bands at 2 926, 2 855 and 1 747 cm(-1), which can be assigned to the absorption of lipids. The spectra of fruiting body exhibit complicated patterns in the interval between 1 800 and 750 cm(-1), which may be used to discriminate different species of Amanitaceae mushrooms. In addition, FTIR spectral differences were observed between different parts of Amanita manginiana. The result suggests that the chemical constituents are various in different parts of fruiting bodies. It is showed that FTIR spectroscopic method is a valuable tool for rapid and nondestructive identification of Amanita mushrooms.

[Fourier transform infrared spectroscopic study of truffles].

Truffles, which belong to ascomycetes, are rare wild growing edible mushrooms; their fruit body contains high nutritive value composition, and their polysaccharide constituents have potential medical applications. In the present paper, Fourier transform infrared (FTIR) spectroscopy was used for obtaining vibrational spectra of mushrooms of truffles growing in mountains of Yunnan province, southwest China. The results show that the mushrooms exhibit characteristic spectra. The two strongest absorption bands appear at about 1 077 and 1 042 cm(-1), respectively. The spectra exhibit complicated patterns between 1200 and 750 cm(-1), which may be used as fingerprints to discriminate different species of truffles. Great changes were also found between mold and healthy truffles, showing major differences observed in the bands of protein. In addition, some vibrational-spectrum differences were observed among the same species of truffles from different growing areas. It is showed that FTIR can provide valuable information about the chemical constituents of intact truffles prior to any extraction method is used.

[Fourier transform infrared spectroscopic study of different parts of wild growing edible mushrooms].

In this paper, vibrational spectra of different parts of fruiting bodies of wild growing mushrooms were recorded with Fourier transform infrared spectrometer. It was different for the spectra of cap skin, gill, cap meat and stem of the same mushroom. The great differences were found between cap skin and other parts of the same mushrooms of Russula virescens and Russula rubra, whereas the spectra of mushroom Termitomyces albuminosus show greated differences between gill and other parts. These indicate variety in the chemical composition of different parts of the same fruiting body. The results suggest that the mushrooms could be identified at the species level by comparison of the vibrational spectra of different parts of fruiting bodies of mushrooms.