Identification, biological characteristics, and control of pathogen causing Pinellia ternata soft rot in Hubei province / 中国中药杂志

This study was designed to identify the pathogen causing soft rot of Pinellia ternata in Qianjiang of Hubei province and screen out the effective bactericides, so as to provide a theoretical basis for the control of soft rot of P. ternata. In this study, the pathogen was identified based on molecular biology and physiological biochemistry, followed by the detection of pathogenicity and pathogenicity spectrum via plant tissue inoculation in vitro and the indoor toxicity determination using the inhibition zone method to screen out bactericide with good antibacterial effects. The control effect of the bactericide against P. ternata soft rot was verified by the leave and tuber inoculation in vitro. The phylogenetic tree was constructed based on the 16 S rDNA, dnaX gene, and recA gene sequences, respectively, and the result showed that the pathogen belonged to the same branch as the type strain Dickeya fangzhongdai JS5. The physiological and biochemical tests showed that the pathogen was identical to D. fangzhongdai, which proved that the pathogen was D. fangzhongdai. The pathogenicity test indicated that the pathogen could obviously infect leaves at 24 h and tubers in 3 d. As revealed by the indoor toxicity test, 0.3% tetramycin, 5% allicin, and 80% ethylicin had good antibacterial activities, with EC_(50) values all less than 50 mg·L~(-1). Tests in tissues in vitro showed that 5% allicin exhibited the best control effect, followed by 0.3% tetramycin and 10% zhongshengmycin oligosaccharide, and their preventive effects were better than curative effects. Therefore, 5% allicin can be used as the preferred agent for the control of P. ternata soft rot, and 0.3% tetramycin and 10% zhongshengmycin oligosaccharide as the alternatives. This study has provided a certain theoretical basis for the control of P. ternata soft rot.

Diagnostic accuracy of a dynamically increased red blood cell distribution width in very low birth weight infants with serious bacterial infection.

OBJECTIVE: Serious bacterial infection (SBI) remains an important cause of morbidity and mortality in preterm infants. The objective of this study was to evaluate the dynamically increased value of the red cell distribution width (RDW) in the diagnosis of SBI. METHODS: This retrospective study enrolled 334 preterm infants with birth weight less than 1500 g. The initial RDW and the maximum value of RDW during hospitalization were extracted from the MIMIC-III database (version 1.4). Infants were categorized into four groups according to baseline RDW value and ΔRDW (ΔRDW = RDW at maximum- RDW at baseline). Logistic regression analysis was used to assess the risk of developing SBI in each group. A receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic value of RDW at baseline alone, ΔRDW alone, and in combination. RESULTS: Infants with increased RDW at baseline (> 17%) and ΔRDW > 2% exhibited the highest risk of developing SBI, whereas the patients with normal RDW level at baseline (≤ 17%) and ΔRDW≤2% (the reference group) had the lowest risk. This association remained unaltered even after adjustment in multivariable models. Basing on ROC curve analysis, the area under the curve predicted by the combination of RDW at baseline and ΔRDW for SBI was 0.81 (95% CI, 0.76-0.87). Sensitivity and specificity were 78.16 and 72.47% respectively. CONCLUSIONS: We observed that combination of elevated RDW at baseline and dynamic increases during hospitalization is significantly associated with SBI. Therefore, that combination could be a promising independent diagnostic indicator of SBI in newborns.

Effects of biocontrol strain BZJN1 and streptoprofen on physicochemical properties and bacteria structure of rhizosphere soil of Atractylodes macrocephala / 中国中药杂志

Soil microorganisms are one of the important biological indictors of soil quality and can reflct the comprehensive ecological environment characteristics of the soil. The research of soil microbial diversity is the key to know the ecological functions and balance with soil. In this paper, high-throughput sequencing on PCR-amplified 16 S rRNA gene V3-V4 fragments was used to determine the bacterial diversity in rhizosphere soil of A. macrocephala under the treatment with BZJN1 or streptoprofen. The results showed that there were no significant differences of the bacteria in A. macrocephala rhizosphere soil of the streptoprofen treatment group and the biocontrol BZJN1 treatment group. All the soil bacteria was classified into 25 categories,67 classes, 108 orders, 167 families and 271 generas, except some unidentified bacteria. Proteobacteria(30.7%-34.8%) was the dominant phylum, of which Alphaproteobacteria(16.8%-18.5%) was the dominant subgroup. Compared with the control group, the relative abundance of multiple phylums bacteria in the rhizosphere soil of A. macrocephala was significantly changed in the streptoprofen treatment group and the biocontrol BZJN1 treatment group. In addition, RDA analysis showed that there was connection with different environmental factors and microbial communities. The abundance of the three genera in the rhizosphere soil of A. macrocephala was significantly positively correlated with Invertase, Urease and AP. PICRUSt function prediction results showed that BZNJ1 could enhance some bacterial functions and promote the plant growth. Biocontrol is a new type of green and safety control pest method. BZNJ1 significantly enhances some bacterial functions on the basis of effectively preventing root rot of A. macrocephala and promoting plant growth, and has no significant effect on the soil bacterial community structure. All the results can provide theoretical support for popularization of BZNJ1.