Exopolysaccharides of Paenibacillus polymyxa: A review.

Paenibacillus polymyxa (P. polymyxa) is a member of the genus Paenibacillus, which is a rod-shaped, spore-forming gram-positive bacterium. P. polymyxa is a source of many metabolically active substances, including polypeptides, volatile organic compounds, phytohormone, hydrolytic enzymes, exopolysaccharide (EPS), etc. Due to the wide range of compounds that it produces, P. polymyxa has been extensively studied as a plant growth promoting bacterium which provides a direct benefit to plants through the improvement of N fixation from the atmosphere and enhancement of the solubilization of phosphorus and the uptake of iron in the soil, and phytohormones production. Among the metabolites from P. polymyxa, EPS exhibits many activities, for example, antioxidant, immunomodulating, anti-tumor and many others. EPS has various applications in food, agriculture, environmental protection. Particularly, in the field of sustainable agriculture, P. polymyxa EPS can be served as a biofilm to colonize microbes, and also can act as a nutrient sink on the roots of plants in the rhizosphere. Therefore, this paper would provide a comprehensive review of the advancements of diverse aspects of EPS from P. polymyxa, including the production, extraction, structure, biosynthesis, bioactivity and applications, etc. It would provide a direction for future research on P. polymyxa EPS.

Role of magnetic resonance diffusion-weighted imaging in differentiating lacrimal masses.

PURPOSE: To evaluate the role of magnetic resonance (MR) diffusion-weighted imaging (DWI) in discriminating lacrimal masses, including neoplastic and nonneoplastic entities. MATERIALS AND METHODS: Forty-four patients with lacrimal masses underwent conventional MRI and DWI. The apparent diffusion coefficient (ADC) values of each mass and the ipsilateral temporal lobe were measured and the ratios of the lesion to temporal lobe ADC were calculated. RESULTS: Pleomorphic adenomas had significantly higher ADC values (1.37 ± 0.22 × 10(-3) mm(2) /sec) and ADC ratios (1.85 ± 0.34) than malignant tumors (1.03 ± 0.19 × 10(-3) mm(2) /sec, 1.37 ± 0.27) (P < 0.001), inflammatory pseudotumors (0.9 ± 0.08 × 10(-3) mm(2) /sec, 1.19 ± 0.07) (P < 0.01), reactive lymphoid hyperplasias (RLHs) (0.6 ± 0.06 × 10(-3) mm(2) /sec, 0.79 ± 0.07) (P < 0.001), and lymphomas (0.55 ± 0.06 × 10(-3) mm(2) /sec, 0.74 ± 0.08) (P < 0.001). RLHs and lymphomas had significantly lower ADC values and ADC ratios than malignant tumors (P < 0.05) and inflammatory pseudotumors (P < 0.05). An ADC value of less than 1.14 × 10(-3) mm(2) /sec and an ADC ratio of less than 1.6 were optimal for differentiating malignant tumors from benign tumors (sensitivity: 80 and 90%, specificity: 100 and 88.9%, respectively). An ADC value of less than 0.76 × 10(-3) mm(2) /sec and an ADC ratio of less than 1.0 were optimal for distinguishing lymphoproliferative disorders from inflammatory pseudotumors (sensitivity: 100%, specificity: 100% for both). CONCLUSION: DWI can help differentiate lacrimal masses and provides a potential clinical tool for noninvasive tissue characterization.