Comparison of the diagnostic performances between strain elastography and shear-wave elastography in differentiation of benign and malignant solid breast lesions / 中华医学超声杂志（电子版）

Objective To compare the diagnostic performances of strain elastography (SE) and shear-wave elastography (SWE) in differentiating benign and malignant solid breast lesions. Methods From January 2015 to December 2015, 150 patients with 155 lesions were examined with SE and SWE respectively in the First Affiliated Hospital with Nanjing Medical University. Elasticity scores on a improved 5-point scale,strain ratio (SR), maximum elasticity (Emax), mean elasticity (Emean), standard deviation of the elasticity (Esd) and the lesion-to-fat elasticity ratio (Eratio) were assessed. The receiver operating characteristic (ROC) curve of SE and SWE parameters were plotted to assess the value in distinguishing benign and malignant breast lesions. The results were compared using the area under the ROC curve (AUC). The accuracy of the parameters with the largest AUC were compared between SE and SWE by McNemar test in different breast imaging reporting and data system (BI-RADS) categories. Results The AUC of elasticity scores, SR, Emax,Emean, Esd and Eratio were 0.823, 0.810, 0.877, 0.835, 0.881 and 0.853, respectively. The SE and SWE parameter with the largest AUC were elasticity scores and Esd respectively. The accuracy of Esd was higher than that of elasticity scores(86.3% vs 64.7%)in 4A lesions (2=4.639, P < 0.05). There were no significant differences in accuracy in other BI-RADS categories. Conclusions Both SE and SWE were helpful for the differentiation of benign and malignant solid breast lesions, and the diagnostic performance of SE and SWE was similar. The optimization of elastography can be achieved by combination with BI-RADS.

Progress in the understanding of the function of atypical response regulators: a review / 生物工程学报

Two component system is a signal transduction system. It typically consists of a sensor histitine kinase and a cognate response regulator (RR) component. The activity of RR is regulated by a phosphorylation dependent mechanism. In recent years, the existence of atypical response regulators (ARRs), which rely on a phosphorylation independent mechanism to regulate their activity, have been recognized. ARRs are involved in the regulation of bacterial growth and development, antibiotic biosynthesis, iron transport, among others. Here we review the recent advances in the understanding of the structure and function of atypical response regulators, by using JadR1, a regulator in jadomycin biosynthesis in Streptomyces, as an example to elucidate the novel mechanism used by ARR to fine-tune its activity.

Identification of key residues in the catalytic center JadH involved in binding substrates or catalysis of jadomycin biosynthesis / 生物工程学报

JadH is a bifunctional hydoxylase/dehydrase involved in jadomycin biosynthesis; it catalyzes a post-PKS modification reaction to convert 2,3-dehydro-UWM6 to dehydrorabelomycin. To identify the key residues involved in substrate-binding and catalysis, structural modeling and multiple sequence alignments of JadH homologs were performed to predict nine residues at the proximity of substrate. Site-directed mutagenesis of the corresponding residues and in vitro evaluation of the activities of the mutant enzymes, indicate these mutations severely reduced JadH activity. Our results indicate these residues are specifically involved in substrate-binding or catalysis in JadH.

Structure and function of tonoplast Cation/H+ antiporters in plant: a review / 生物工程学报

Cation transporters play important roles in modulating the concentration of intracellular metal ions. The vacuole is an important storage organelle for many ions. Cation (Ca+)/H+ antiporters (CAXs) located at vacuolar membrane are mainly involved in the Ca2+ flux into the vacuole, and appear to be capable of transporting various divalent cations to some degree. Several CAX genes have been isolated and characterized from various plants in recent years. Four domains of plant CAXs have been identified: NRR regulates Ca2+ transport by a mechanism of N-terminal autoinhibition; Ca domain and C domain confer Ca2+ and Mn2+ specificity among CAX transporters, respectively; D domain plays a part in the regulation of cytosolic pH. AtCAXs identified in Arabidopsis thaliana are involved in the growth, development and stress adaption of plant. AtCAX3 is the mainly Ca2+/H+ transporter in response to salt stress; AtCAX2 and AtCAX4 participate in transportation and detoxicification of heavy metal ions (Cd2+, Zn2+, and Mn2+) in cells under heavy metal stress, and impact root/shoot Cd partitioning in plant. These suggest that CAX genes may be useful for nutritional enhancement of plants, and for increasing phytoremediation potential. Here, the classification, structure and function of CAXs in plants are reviewed.