Deep-Sequencing Analysis of the Mouse Transcriptome Response to Infection with Brucella melitensis Strains of Differing Virulence

Brucella melitensis is an important zoonotic pathogen that causes brucellosis, a disease that affects sheep, cattle and occasionally humans. B. melitensis strain M5-90, a live attenuated vaccine cultured from B. melitensis strain M28, has been used as an effective tool in the control of brucellosis in goats and sheep in China. However, the molecular changes leading to attenuated virulence and pathogenicity in B. melitensis remain poorly understood. In this study we employed the Illumina Genome Analyzer platform to perform genome-wide digital gene expression (DGE) analysis of mouse peritoneal macrophage responses to B. melitensis infection. Many parallel changes in gene expression profiles were observed in M28- and M5-90-infected macrophages, suggesting that they employ similar survival strategies, notably the induction of anti-inflammatory and antiapoptotic factors. Moreover, 1019 differentially expressed macrophage transcripts were identified 4 h after infection with the different B. melitensis strains, and these differential transcripts notably identified genes involved in the lysosome and mitogen-activated protein kinase (MAPK) pathways. Further analysis employed gene ontology (GO) analysis: high-enrichment GOs identified endocytosis, inflammatory, apoptosis, and transport pathways. Path-Net and Signal-Net analysis highlighted the MAPK pathway as the key regulatory pathway. Moreover, the key differentially expressed genes of the significant pathways were apoptosis-related. These findings demonstrate previously unrecognized changes in gene transcription that are associated with B. melitensis infection of macrophages, and the central signaling pathways identified here merit further investigation. Our data provide new insights into the molecular attenuation mechanism of strain M5-90 and will facilitate the generation of new attenuated vaccine strains with enhanced efficacy

Complete Genome Sequences of Brucella melitensis Strains M28 and M5-90, with Different Virulence Backgrounds▿

Brucella melitensis is a Gram-negative coccobacillus bacteria belonging to the Alphaproteobacteria subclass. It is an important zoonotic pathogen that causes brucellosis, a disease affecting sheep, cattle, and sometimes humans. The B. melitensis strain M5-90, a live attenuated vaccine cultured from the B. melitensis virulent strain M28, has been an effective tool to control brucellosis in goats and sheep in China. Here we report the complete genome sequences of B. melitensis M28 and M5-90, strains with different virulence backgrounds, which will serve as a valuable reference for future studies

In Situ Di‑, Piezo‑, Ferroelectric Properties and Domain Configurations of Pb(Sc_1/2Nb_1/2)O₃–Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ Ferroelectric Crystals

Relaxor ferroelectric crystals, such as Pb­(Mg_1/3Nb_2/3)­O₃–PbTiO₃ and Pb­(Zn_1/3Nb_2/3)­O₃–PbTiO₃, exhibit high piezoelectric properties. However, they cannot meet the need of high power transducers, due to their low phase transition temperatures and low coercive fields. Thus, it is urgent to develop new-type ferroelectric crystals. Here, a ternary solid solution of Pb­(Sc_1/2Nb_1/2)­O₃–Pb­(Mg_1/3Nb_2/3)­O₃–PbTiO₃ is a good candidate. By the regulation of growth techniques and the control of raw compositions, Pb­(Sc_1/2Nb_1/2)­O₃–Pb­(Mg_1/3Nb_2/3)­O₃–PbTiO₃ crystals with different compositions are obtained, which present perovskite phases without any trace of impurity. In situ investigations of di-, piezo-, ferroelectric properties and the observation of domain configurations are realized in Pb­(Sc_1/2Nb_1/2)­O₃–Pb­(Mg_1/3Nb_2/3)­O₃–PbTiO₃ crystals, which exhibit large di-, ferro-, piezoelectric responses, typical domain switching, high poled and thermal stabilities. At room temperature, the maximum piezoelectric constant is found to be 1550 pC/N, with the maximum peak to peak strain value of 0.57% and coercive field of 4–6 kV/cm. The speckle-shaped nanodomains and butterfly hysteresis loops represented by the variation of amplitudes further indicate large piezoelectric responses of PSN–PMN–PT crystals. Furthermore, the rhombohedral–tetragonal phase transition temperature is more than 120 °C, indicating good thermal stabilities with stable ferroelectricity and large piezoelectric response in a wide temperature range