Cost-Efficient Production of the Sphingan WL Gum by Sphingomonas sp. WG Using Molasses and Sucrose as the Carbon Sources.

The polysaccharide WL gum is produced by the marine microorganism Sphingomonas sp. WG and presents great commercial utility potential in many industries especially in oil industries. However, the high fermentation cost limits its wide application. Therefore, an efficient production system at a lower cost was established using beet molasses to partially replace the commonly used carbon sources. Four different molasses were screened and their composition was investigated. One-factor design and RSM statistical analysis were employed to optimize the WL gum fermentation medium. The effects of molasses on the rheological properties and gene expression of WL gum were also investigated. The results showed that the pretreated beet molasses generated both high broth viscosity and WL gum production (12.94 Pa·s and 11.16 g/L). Heavy metal ions and ash were found to be the key factors in unpretreated and pretreated molasses affecting WL production. The cost-efficient production medium contained (g/L): sucrose 61.79, molasses 9.95, yeast extract 1.23, K2HPO4 1, MgSO4 0.1, ZnSO4 0.1 and the WL gum production reached 40.25 ± 1.15 g/L. The WL gum product WL-molasses showed the higher apparent viscosity, and viscous modulus and elastic modulus than WL-sucrose and WL-mix, which might be related to its highest molecular mass. The higher expressional level of genes such as pgm, ugp, ugd, rmlA, welS, and welG in WL gum synthesis in the mixed carbon source medium caused the high production and broth viscosity. This work provided a cost-efficient method for WL gum production.

Diagnostic Value of Preoperative Needle Biopsy for Tumor Grading Assessment in Hepatocellular Carcinoma.

BACKGROUND: Needle core biopsy (NCB) is one of the most widely used and accepted methods for the diagnosis of focal hepatic lesions. Although many studies have assessed the diagnostic accuracy of NCB in predicting the tumor grade, it is still under debate. OBJECTIVE: To identify the influence of number of biopsies on NCB diagnostic accuracy. METHODS: 153 patients with HCC were selected from patients who received preoperative NCB under the guidance of ultrasonography in our hospital. The diagnostic reference standard was the surgical pathologic diagnosis. RESULTS: Using a 3-tier grading scheme (well, moderate and poor), the accuracy of NCB has no significant differences among different number of passes in HCC ≤5 cm. For HCC >5≤8 cm, the increasing number of passes could increase the diagnostic accuracy (63.3%, 81.8%, and 84.8% for passes one, two, and three, respectively). While in HCC>8 cm, the diagnostic accuracy of passes one, two, and three were 62.1%, 69%, and 75.8%, respectively. CONCLUSIONS: The accuracy of NCB in assessing tumor grading associated with tumor size and number of passes. Meanwhile, a minimum of two passes should be performed to get better accuracy in patients with HCC >5 cm.