Expression and Characterization of a Novel Cold-Adapted Chitosanase from Marine Renibacterium sp. Suitable for Chitooligosaccharides Preparation.

(1) Background: Chitooligosaccharides (COS) have numerous applications due to their excellent properties. Chitosan hydrolysis using chitosanases has been proposed as an advisable method for COS preparation. Although many chitosanases from various sources have been identified, the cold-adapted ones with high stability are still rather rare but required. (2) Methods: A novel chitosanase named CsnY from marine bacterium Renibacterium sp. Y82 was expressed in Escherichia coli, following sequence analysis. Then, the characterizations of recombinant CsnY purified through Ni-NTA affinity chromatography were conducted, including effects of pH and temperature, effects of metal ions and chemicals, and final product analysis. (3) Results: The GH46 family chitosanase CsnY possessed promising thermostability at broad temperature range (0-50 °C), and with optimal activity at 40 °C and pH 6.0, especially showing relatively high activity (over 80% of its maximum activity) at low temperatures (20-30 °C), which demonstrated the cold-adapted property. Common metal ions or chemicals had no obvious effect on CsnY except Mn2+ and Co2+. Finally, CsnY was determined to be an endo-type chitosanase generating chitodisaccharides and -trisaccharides as main products, whose total concentration reached 56.74 mM within 2 h against 2% (w/v) initial chitosan substrate. (4) Conclusions: The results suggest the cold-adapted CsnY with favorable stability has desirable potential for the industrial production of COS.

Histogram analysis of apparent diffusion coefficient maps in the prognosis of patients with locally advanced head and neck squamous cell carcinoma: Comparison of different region of interest selection methods.

OBJECTIVE: To investigate the influence of different region of interest (ROI) selection methods on the histogram analysis of apparent diffusion coefficient (ADC) maps and to compare their performance in predicting overall survival (OS) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). METHODS: A total of 73 patients with locally advanced HNSCC who underwent pretreatment diffusion-weighted magnetic resonance imaging were included. Based on the largest slice ROI (ROILS) and whole tumor ROI (ROIWT), ADC histogram parameters including mean ADC (ADCmean); median ADC (ADCmedian); 10th, 25th, 75th, and 90th percentiles of ADC values (ADC10, ADC25, ADC75, and ADC90); kurtosis; and skewness were obtained. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to evaluate measurement reproducibility. The association of ADC histogram parameters and clinicopathological factors with OS was analyzed using log-rank tests and Cox regression. RESULTS: The measurements of ADC histogram parameters based on ROIWT showed better reproducibility than ROILS (ICCs for ROIWT: 0.772-0.961; ICCs for ROILS: 0.511-0.851). The higher ADC values (ADCmean, ADCmedian, ADC10, and ADC25 based on both ROIs; ADC75 based on ROILS) and lower kurtosis based on ROILS were significantly associated with worse OS of patients with locally advanced HNSCC (all P < 0.05). In the multivariate Cox analysis, ADC10 measured with ROIWT (P = 0.019, hazard ratio = 2.63, 95% confidence interval 1.17-5.90) was an independent prognostic factor after adjusting for clinicopathological factors. CONCLUSIONS: ROI selection methods could influence ADC histogram analysis. ADC10 based on ROIWT had the best independent prognostic value for patients with locally advanced HNSCC.

Chemotherapeutic activities of Carthami Flos and its reversal effect on multidrug resistance in cancer cells.

Multidrug-resistance (MDR) represents a major cause of failure in cancer chemotherapy. The need for a reduction in MDR by natural-product-based drugs of low toxicity led to the current investigation of applying medicinal herbs in future cancer adjuvant therapy. Carthami Flos (CF), the dried flower of safflower (Carthamus tinctorius L.), is one of the most popular traditional Chinese medicinal herbs used to alleviate pain, increase circulation, and reduce blood-stasis syndrome. The drug resistance index of the total extract of CF in MDR KB-V1 cells and its synergistic effects with other chemotherapeutic agents were studied. SRB cell viability assays were used to quantify growth inhibition after exposure to single drug and in combinations with other chemotherapeutic agents using the median effect principle. The combination indexes were then calculated according to the classic isobologram equation. The results revealed that CF showed a drug resistance index of 0.096. In combination with other chemotherapeutic agents, it enhanced their chemo-sensitivities by 2.8 to 4.0 folds and gave a general synergism in cytotoxic effect. These results indicate that CF could be a potential alternative adjuvant antitumour herbal medicine representing a promising approach to the treatment of some malignant and MDR cancers in the future.