Phosphoproteomic Analysis Reveals the Predominating Cellular Processes and the Involved Key Phosphoproteins Essential for the Proliferation of Toxoplasma gondii.

PURPOSE: To explore the essential roles of phosphorylation in mediating the proliferation of T. gondii in its cell lytic life. METHODS: We profiled the phosphoproteome data of T. gondii residing in HFF cells for 2 h and 6 h, representing the early- and late-stages of proliferation (ESP and LSP) within its first generation of division. RESULTS: We identified 70 phosphoproteins, among which 8 phosphoproteins were quantified with the phosphorylation level significantly regulated. While only two of the eight phosphoproteins, GRA7 and TGGT1_242070, were significantly down-regulated at the transcriptional level in the group of LSP vs. ESP. Moreover, GO terms correlated with host membrane component were significantly enriched in the category of cellular component, suggesting phosphoprotein played important roles in acquiring essential substance from host cell via manipulating host membrane. Further GO analysis in the categories of molecular function and biological process and pathway analysis revealed that the cellular processes of glucose and lipid metabolism were regulated by T. gondii phosphoproteins such as PMCAA1, LIPIN, Pyk1 and ALD. Additionally, several phosphoproteins were enriched at the central nodes in the protein-protein interaction network, which may have essential roles in T. gondii proliferation including GAP45, MLC1, fructose-1,6-bisphosphate aldolase, GRAs and so on. CONCLUSION: This study revealed the main cellular processes and key phosphoproteins crucial for the intracellular proliferation of T. gondii, which would provide clues to explore the roles of phosphorylation in regulating the development of tachyzoites and new insight into the mechanism of T. gondii development in vitro.

Isolation, identification and lead adsorption study of lead-resistant Lactobacillus casei strains from feces of healthy newborns / 南方医科大学学报

<p><b>OBJECTIVE</b>To isolate and identify lead-resistant Lactobacillus casei strains with lead adsorption ability from the stool of healthy newborns as a new source of bacteria for developing lead-eliminating food products.</p><p><b>METHODS</b>MRS was used to isolate lead-resistant bacteria from the feces of 30 healthy and full-term neonates. A phylogenetic tree was constructed based on the morphological characteristics and 16S rRNA sequences of the isolated bacteria. Physiological and biochemical characterizations of the bacteria were performed according to the Berger's Systematic Bacteriology Handbook, followed by antimicrobial susceptibility test and acid-tolerant bile salt test. The adsorption capacity of Pbof the bacteria was determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES).</p><p><b>RESULTS</b>Three strains of Lactobacillus casei were isolated, which were resistant to penicillin and ceftriaxone and could tolerate the exposure to 500 mg/L Pb. Acid-tolerant bile salt test showed that the bacteria were resistant to culture in the presence of artificial gastric juice (pH 2.0) for 3 h, and their survival rate reached 62.5% following exposure to 0.3% bile salt for 8 h. The bacteria showed a Pbadsorption rate of 90.4% at a low Pbconcentration (1 mg/L) and of 86.27% at a high Pbconcentration (50 mg/L).</p><p><b>CONCLUSION</b>Three Lactobacillus casei strains lead adsorption ability were isolated from the feces of newborns. These bacterial strains provide a new solution to alleviate lead poisoning by probiotic dietary.</p>