Specific detection of Lysobacter antibioticus strains in agricultural soil using PCR and real-time PCR.

Lysobacter antibioticus is an important biocontrol bacteria against phytopathogens in soil, and with the ability to produce nonvolatile antimicrobial metabolites has been extensively characterised. It is important to establish applicable techniques to detect and monitor L. antibioticus directly and accurately in soil samples. We developed and tested 13 primer sets according to phenazine gene (phzA, phzB, phzD, phzF, phzS) and the cyclohexanone monooxygenase gene (phzNO1); a pair of primer phzNO1 F1/phzNO1 R1 based on the cyclohexanone monooxygenase (phzNO1) gene of L. antibioticus strain OH13 was selected and optimized polymerase chain reaction (PCR) amplification conditions for rapid and accurate detection. After screening eight strains of L. antibioticus, two strains of Lysobacter enzymogenes, one strain of Lysobacter capsici, Arthrobacterium, Bacillus, Microbacterium, Burkholderia, Pseudomonas and other bacterial strains isolated from different agricultural soils, the phzNO1 F1/phzNO1 R1 primers amplified a single PCR band of about 229 bp from L. antibioticus. The detection sensitivity with primers phzNO1 F1/phzNO1 R1 was 5.14 × 104 fg/25µL of genomic DNA and 2.254 × 1010 to 2.254 × 1011 colony-forming units/mL for the soil samples. Quantitative PCR assays were to develope as a specific method to monitor the L. antibioticus population in soil as well as guide soil micro-ecological management.

The scanning effect of the injection flow rate of contrast medium on magnetic resonance image dynamic contrast-enhanced of prostate cancer / 实用医学杂志

Objective To investigate the effect of perfusion index of the injection flow rate of contrast medium on magnetic resonance image dynamic contrast-enhanced (DCE-MRI) of prostate cancer with different pathological grades. Methods Seventy patients with PCa、cardiac, normal renal function is and BMI≤25 kg/m2 were enrolled. The 2.5 mL/s, 5.0 mL/s dynamic enhanced injection velocity contrast agent was used for 35 patients and the reast 35 patients, respectively. All data was transferred to GE Advanced Workstation 4.3, and the indexes of the peripheral prostate cancerous zone were calculated by Functool2 of signal intensity time (SI-T), The time to minimum (Tmax), the whole enhancement degree (SImax%) and the maximum slope (Rmax) were calculated. The effect of different injection velocity on the dynamic enhanced perfusion index was analyzed. Results Tmax of pa-tients received 2.5 mL/s, 5.0 mL/s contrast agent injection velocity in the low risk group (Gleason score 2 to 6)、medium risk group (7 Gleason score) and high risk group (Gleason score 8 to 10) were (19.89 ± 2.76) s and (15.42 ± 1.68) s, (16.91 ± 2.34) s and (12.88 ± 1.73) s, (14.13 ± 1.81) s and (10.2 ± 1.42) s, with signifi-cant differences (t = 4.61, 3.1, 3.25, P < 0.01). The average SImax% of PCa in the two groups were (1.45 ± 0.17)%and (1.51 ± 0.27)%, (1.62 ± 0.12)%and (1.84 ± 0.18)%, (1.86 ± 0.16)% and (2.11 ± 0.28)%, Two groups of SImax% were statistically significant difference (t = -2.44, -4.55, -5.16, P < 0.05), respectively. The average Rmax of PCa of the two groups were (6.29 ± 2.62)% and (7.64 ± 4.09)%,(8.92 ± 4.21)% and (10.24 ± 9.09)%, (10.85 ± 2.89)% and (12.43 ± 3.51)%, with significant difference (t = -4.07,-3.85, -8.68, P <0.01). Tmax was shorter, SImax% and Rmax were higher of prostate cancer patients received 5.0 mL/s contrast agent injection velocity than those received 2.5 mL/s contrast agent injection velocity. Conclusion The dynamic enhancement perfusion index of prostate cancer patients received 5.0 mL/s contrast agent injection velocity is more sensitive than that of patients received 2.5 mL/s contrast agent injection velocity , which can improve the diagnosis of prostate cancer.