Preparation of Nanomaterial Wettable Powder Formulations of Antagonistic Bacteria from Phellodendron chinense and the Biological Control of Brown Leaf Spot Disease

Yanling Zeng,Han Liu,Tianhui Zhu,Shan Han,Shujiang Li 한국식물병리학회 2021 Plant Pathology Journal Vol.37 No.3

Brown leaf spot disease caused by Nigrospora guilin- ensis on Phellodendron chinense occurs in a large area in Dayi County, Chengdu City, Sichuan Province, China each year. This outbreak has severely reduced the production of Chinese medicinal plants P. chinense and caused substantial economic losses. The bacterial isolate JKB05 was isolated from the healthy leaves of P. chinense, exhibited antagonistic effects against N. guilinensis and was identified as Bacillus megaterium. The following fermentation medium and conditions improved the inhibitory effect of B. megaterium JKB05 on N. guilinensis: 2% glucose, 0.1% soybean powder, 0.1% KCl, and 0.05% MgSO4; initial concentration 6 × 106 cfu/ml, and a 42-h optimal fermentation time. A composite of 0.1% nano-SiO2 JKB05 improved the thermal stability, acid-base stability and ultraviolet resistance by 16%, 12%, and 38.9%, respectively, and nano-SiO2 was added to the fermentation process. The best formula for the wettable powder was 35% kaolin, 4% polyethylene glycol, 8% Tween, and 2% humic acid. The following quality test results for the wettable powder were obtained: wetting time 87.0 s, suspension rate 80.33%, frequency of microbial contamination 0.08%, pH 7.2, fineness 95.8%, drying loss 1.47%, and storage stability ≥83.5%. A pot experiment revealed that the ability of JKB05 to prevent fungal infections on P. chinense increased considerably and achieved levels of control as high as 94%. The use of nanomaterials significantly improved the ability of biocontrol bacteria to control this disease.

Screening of Endophytic Antagonistic Bacterium from Phellodendron amurense and Their Biocontrol Effects against Canker Rot

Li, Shujiang,Fang, Xinmei,Zhang, Hanlian,Zeng, Yanling,Zhu, Tianhui The Korean Society of Plant Pathology 2019 Plant Pathology Journal Vol.35 No.3

Thirty-four strains of bacteria were isolated from Phellodendron amurense. Using Nectria haematococca as an indicator strain, the best strain, B18, was obtained by the growth rate method. The morphological, physiological and biochemical characteristics of strain B18 and its 16S DNA gene sequence were identified, and the biocontrol effect of strain B18 was assessed in pot and field tests, as well as in a field-control test. Drilling methods were used to determine the antibacterial activity of metabolites from strain B18 and their effects on the growth of pathogen mycelia and spores. The best bacteriostatic rate was 85.4%. B18 can hydrolyse starch and oxidize glucose but does not produce gas; a positive result was obtained in a gelatine liquefaction test. According to 16S DNA gene sequencing, strain B18 is Bacillus methylotrophicus (GenBank accession number: MG457759). The results of pot and field-control trials showed 98% disease control when inoculating $10^8cfu/ml$ of the strain. The disease control effect of the B18 culture liquid (concentrations of $10^8$, $2{\times}10^6$, $10^6$, $5{\times}10^5$ and $2.5{\times}10^5cfu/ml$) in the field-control test was higher than 80%, and the cure rate of the original delivery solution was 96%. Therefore, in the practical forestry production, a $2.5{\times}10^5cfu/ml$ culture liquidshould be applied in advance to achieve good control effects.

Screening of Endophytic Antagonistic Bacterium from Phellodendron amurense and Their Biocontrol Effects against Canker Rot

Shu-Jiang Li,Xinmei Fang,Hanlian Zhang,Yanling Zeng,Tian-Hui Zhu 한국식물병리학회 2019 Plant Pathology Journal Vol.35 No.3

Thirty-four strains of bacteria were isolated from Phellodendron amurense. Using Nectria haematococca as an indicator strain, the best strain, B18, was obtained by the growth rate method. The morphological, physiological and biochemical characteristics of strain B18 and its 16S DNA gene sequence were identified, and the biocontrol effect of strain B18 was assessed in pot and field tests, as well as in a field-control test. Drilling methods were used to determine the antibacterial activity of metabolites from strain B18 and their effects on the growth of pathogen mycelia and spores. The best bacteriostatic rate was 85.4%. B18 can hydrolyse starch and oxidize glucose but does not produce gas; a positive result was obtained in a gelatine liquefaction test. According to 16S DNA gene sequencing, strain B18 is Bacillus methylotrophicus (GenBank accession number: MG457759). The results of pot and field-control trials showed 98% disease control when inoculating 108 cfu/ ml of the strain. The disease control effect of the B18 culture liquid (concentrations of 108, 2 × 106, 106, 5 × 105 and 2.5 × 105 cfu/ml) in the field-control test was higher than 80%, and the cure rate of the original delivery solution was 96%. Therefore, in the practical forestry production, a 2.5 × 105 cfu/ml culture liquidshould be applied in advance to achieve good control effects.

Detection of Spinal Muscular Atrophy Using a Duplexed Real-Time PCR Approach With Locked Nucleic Acid-Modified Primers

Pan Jianyan,Zhang Chunhua,Teng Yanling,Zeng Sijing,Chen Siyi,Liang Desheng,Li Zhuo,Wu Lingqian 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.1

Background: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder mainly caused by homozygous deletions that include exon 7 of the survival motor neuron 1 (SMN1) gene. A nearby paralog gene, SMN2, obstructs the specific detection of SMN1. We optimized a duplexed real-time PCR approach using locked nucleic acid (LNA)-modified primers to specifically detect SMN1. Methods: An LNA-modified primer pair with 3´ ends targeting SMN1 specific sites c.835-44g and c.840C was designed, and its specificity was examined by real-time PCR and Sanger Sequencing. A duplexed real-time PCR approach for amplifying SMN1 and control gene albumin (ALB) was developed. A randomized double-blind trial with 97 fresh peripheral blood samples and 25 dried blood spots (DBS) was conducted to evaluate the clinical efficacy of the duplexed approach. This new approach was then used to screen 753 newborn DBS. Results: The LNA-modified primers exhibited enhanced specificity and 6.8% increased efficiency for SMN1 amplification, compared with conventional primers. After stabilizing the SMN1 test by optimizing the duplexed real-time PCR approach, a clinical trial validated that the sensitivity and specificity of our new approach for detecting SMA patients and carriers was 100%. Using this new approach, 15 of the screened 753 newborns were identified as carriers via DBS, while the rest were identified as normal individuals. These data reveal a carrier rate of 1.99% in Hunan province, South Central China. Conclusions: We have developed a novel, specific SMN1 detection approach utilizing real-time PCR with LNA-modified primers, which could be applied to both prenatal carrier and newborn screening.

Interpenetration Enhancing of Chitosan-PEGLM Double Network (DN) Hydrogel and Its Properties

Yiting Xu,Jianjie Xie,Hui Gao,Ying Cao,Min Chen,Yanling Liu,Birong Zeng,Feng-Chih Chang,Lizong Dai 한국고분자학회 2015 Macromolecular Research Vol.23 No.1

A series of polylactic acid-polyethylene glycol-polylactic acid diacrylate macromers (PEGLM) were synthesized,and a novel chitosan-PEGLM double network (DN) hydrogel was further successfully fabricated by thesequential interpenetrating technology with highly cross-linked chitosan as the rigid component and PEGLM as theflexible component. Their structures and components were characterized by 1H NMR, FTIR, and XRD. Their fracturemorphology was investigated by SEM. It was interesting to found that the compressive strength of hydrogel woundreach its maximum value when the chitosan content was 10%, no matter what the molecular weight of PEGLM componentwas. What’s more, we found that the compressive strength of 6KL7 could reach 1.07 MPa at gel state, whosePEG segment molecular weight was 6,000, and polymerization degree of PLA was 7. The effects of glutaraldehyderatio, polymerization degree of PLA, and molecular weight of PEG segment on the mechanical strength of DNhydrogels were also discussed in this article. To further strengthen DN hydrogels, the double network-linear (DNL)hydrogels were fabricated by introducing linear poly(vinyl alcohol) (PVA) into the DN hydrogels. The DN-Lhydrogels exhibited better mechanical properties, with the compressive strength up to 1.45 MPa. These hydrogelsmay have prospective applications in the fields of wound dressing, artificial cartilage and tissue engineering scaffoldmaterials which require high mechanical properties.