High Glucose Concentration Promotes Vancomycin-Enhanced Biofilm Formation of Vancomycin-Non-Susceptible Staphylococcus aureus in Diabetic Mice.

We previously demonstrated that vancomycin treatment increased acquisition of eDNA and enhanced biofilm formation of drug-resistant Staphylococcus aureus through a cidA-mediated autolysis mechanism. Recently we found that such enhancement became more significant under a higher glucose concentration in vitro. We propose that besides improper antibiotic treatment, increased glucose concentration environment in diabetic animals may further enhance biofilm formation of drug-resistant S. aureus. To address this question, the diabetic mouse model infected by vancomycin-resistant S. aureus (VRSA) was used under vancomycin treatment. The capacity to form biofilms was evaluated through a catheter-associated biofilm assay. A 10- and 1000-fold increase in biofilm-bound bacterial colony forming units was observed in samples from diabetic mice without and with vancomycin treatment, respectively, compared to healthy mice. By contrast, in the absence of glucose vancomycin reduced propensity to form biofilms in vitro through the increased production of proteases and DNases from VRSA. Our study highlights the potentially important role of increased glucose concentration in enhancing biofilm formation in vancomycin-treated diabetic mice infected by drug-resistant S. aureus.

Photocrosslinkable gellan gum film as an anti-adhesion barrier.

The purpose of this study was to develop a gellan gum-based film which could be photocrosslinked for medical applications. Gellan gum was grafted with cinnamate to yield the photo crosslinkable polymer (gellan gum-cin). This material had 14.7% of its D-galacturonic residues reacted with cinnamate groups and displayed maximum absorption at 254 nm. Investigation of the photochemical properties showed that the crosslinking efficiency was 82% after 16 min of UV irradiation. The anti-adhesion films prepared from gellan gum-cin polymers exhibited high gel contents (88 ± 2%) and suitable mechanical properties. When implanted into rats, the gellan gum-cin film exhibited the most promising anti-adhesion potential in 2 out of 10 rats without forming any tissue adhesion. Furthermore, the gellan gum-cin film could effectively inhibit inflammation in rats based on the results of fluid leukocyte analyses. The gellan gum-cin film thus has potential in clinical applications.

Genetic relationships between resistances to Fusarium head blight and crown rot in bread wheat (Triticum aestivum L.).

Fusarium head blight (FHB) and crown rot (CR) are two wheat diseases caused by the same Fusarium pathogens. Progress towards CR resistance could benefit from FHB-resistant germplasm if the same genes are involved in resistance to these two different diseases. Two independent studies were conducted to investigate the relationship between host resistances to these two diseases. In the first study 32 genotypes were assessed and no significant correlation between their reactions to FHB and CR was detected. The second study was based on a QTL analysis of a doubled haploid population derived from a variety with resistance to both diseases. Results from this study showed that loci conferring resistance to FHB and CR are located on different chromosomes. Together, these results suggest that, despite a common aetiology, different host genes are involved in the resistance against FHB and CR in wheat. Thus, although it is possible that genes affecting both diseases may exist in other germplasm or under different conditions, separate screening seems to be needed in identifying sources of CR resistance.

[Identification of sulphur residue in chrysanthemum by Fourier transform infrared spectroscopy].

Qi and Huai chrysanthemum samples processed in different ways were discriminated by means of Fourier transform infrared (FTIR) spectroscopy. It was shown that different processing methods may result in the variation of relative content of effective components in chrysanthemum. The variation of chemical structure may also occur. And the variations can be reflected differently on the transform infrared spectra. The dry chrysanthemum smoked with sulphur had different characters in the vibration frequency and shape of IR from other samples at 1 600 and 1 060 cm(-1), and showed static characteristic absorptions at 922, 818 and 777 cm(-1), which were stronger than others. The chrysanthemum processed in different ways showed differences in the Fourier transform infrared spectra. The sulphur residue in chrysanthemum can be identified by FTIR without separation and abstraction. This method is not only quick and precise but also convenient and direct. Different sorts of chrysanthemum can be identified in this way.

[Study of flos lonicerae in local herbs and other areas by FTIR spectrum].

The FTIR spectra of flos lonicerae(FL) in four different areas are analysed by FTIR and the comparison of local(Henan) FL and FL in other areas is also studied. The result shows that the FL in different areas have the different content of main effective substance, so their absorption frequency and form in FTIR spectra are different as well. There is an obvious difference between Sichuan and local FL in wave number and form. Although FL in Shandong is famous as local herbs, their spectra are different slightly. The FL in Hebei and Shandong have almost the same spectrum. The local FL has a weak peak at 1 734 cm(-1), however, the FL in Shandong and Hebei don't have. The local FL has a group of weak peaks at 1 522 cm(-1) and others have stronger and independent absorption or split peaks at the same point. The peak forms of local herbs are sharp from 1 155 to 1 045 cm(-1) while those of Shandong and Hebei are flat and split ones. Therefore, FTIR can be not only a fast and reliable method to identify local herbs, but also a method to monitor the cultivating process and to purify and restore the Chinese medicine.

[Identification of wheat varieties by FTIR spectrum].

The spectra of eight kinds of wheat roots were determined by FTIR spectrometry and the absorption peaks were analyzed. Results from the comparison of the spectra showed that there were some differences in the shape, wave number and the number of absorption peaks of their spectra within the same range of wave number. The spectra of different wheat varieties exhibited remarkable differences. The first difference was in the region of 2800-2980 cm(-1) which mainly reflected the stretching vibration of methyl and methylene, the length of molecular chain of compound, and the molecular weight. The second difference existed in the region of 1510-1730 cm(-1), which mainly reflected the substituent nature of amide N and alpha-C. The major differences of spectra in this region might result from the differences in genes. So FTIR spectra could be used for the identification of wheat varieties.