Isolation, identification, and evaluation of the biocontrol potential of a Bacillus velezensis strain against tobacco root rot caused by Fusarium oxysporum.

AIMS: Tobacco (Nicotiana tabacum) is an economically important crop. Root rot caused by Fusarium oxysporum has become a damaging disease in N. tabacum crops grown in Henan province of China. Therefore, the objectives of this study were to screen bacterial isolates against F. oxysporum from rhizosphere soils of tobacco growing areas and to evaluate their antifungal activities, biocontrol effects, and effects on plant growth. METHODS AND RESULTS: Nineteen strains with antifungal inhibition effects of >60% against F. oxysporum were obtained using the method of flat confrontation; the strain Ba-0321 was the strongest, with an antifungal effect of 75%. Moreover, this strain had broad spectrum antimicrobial activity to eight additional tobacco pathogens. The strain was identified as Bacillus velezensis by morphology and the 16S rDNA sequence. The B. velezensis strain Ba-0321 had strong UV resistance as well as tolerance to high temperatures and low nutrition. The bacteria inhibited spore germination and mycelial growth of F. oxysporum under in vitro co-culture conditions. In vivo assays demonstrated that the Ba-0321 strain significantly reduced the pathogenicity of F. oxysporum, resulting in a control effect on tobacco root rot of 81.00%. Simultaneously, the bacteria significantly promoted root development and the growth of tobacco plants. CONCLUSION: Our results confirmed that the B. velezensis strain Ba-0321 has a strong antifungal effect and stress resistance that enable it to be used as a biological control agent for tobacco root rot caused by F. oxysporum. SIGNIFICANCE AND IMPACT OF THE STUDY: Tobacco root rot caused by F. oxysporum has become a damaging disease in China. The B. velezensis strain Ba-0321 has promising application value for controlling tobacco root rot diseases, and it could provide a new biocontrol agent against root rot caused by F. oxysporum in other plant species.

Effect of ligand sequence-specific modification on DNA hybrid catalysis.

Development of a stereoselective asymmetric catalytic system with high conversion is the key to success for acquiring chiral materials. In recent years, DNA hybrid catalysts have attracted significant interest due to their excellent abilities in accelerating reactions and achieving high enantioselectivity. We report here that bipyridine linked with polyamide as a sequence-specific catalytic ligand was designed to perform a DNA hybrid asymmetric reaction. The products presented different stereoselectivities compared to the results of reactions catalyzed by bipyridine. Comparing catalytic experiments based on alternative oligonucleotides verified that sequence-locating of the ligand affected the catalytic microenvironment. Circular dichroism spectra, combined with singular value decomposition, proposed that different binding modes could exist somewhere between the ligand and alternative sequences. The current work provides a strategy to extend the chemical range of DNA-based catalysis.

Metastasis of lung adenocarcinoma to the gingiva: a rare case report.

Metastatic tumors account for 1% of all oral malignancies. Metastasis to jaw bones is common, particularly in the mandible, rare in the oral soft tissues, and account for only 0.1% of oral malignancies. The majority of metastatic cases (70%) reported in the literature have primary tumors located in the lung, breast, kidney, and colon. Metastasis is a biological complex process that involves detachment from the surrounding cells, regulation of cell motility, invasion, survival, proliferation, and evasion of the immune system. Clinical presentation of metastatic tumors is variable, which may create diagnostic dilemma or may lead to erroneous diagnosis. Metastatic tumors clinically mimic as dental infections. Metastasis to the oral soft tissue from lung cancer, especially gingiva is a rare condition. Metastasis to the gingiva can affect the oral function, speech, and nutrition. Most of the cases in the literature reported that lesion presented in oral soft tissues before the diagnosis of primary tumors. Here we report a case of 62-year-old male patient with metastasis from lung to the gingiva, where the metastasis was detected before primary tumor.

Correlative study on lip prints, fingerprints, and mandibular intercanine distance for gender determination.

CONTEXT: "Identity" is a set of physical characteristics, functional or psychic, normal or pathological, that defines an individual. Identification of an individual is a crucial and an exigent task in forensic investigation. AIMS: The aim of the present pilot study was to investigate the accuracy of various methods employed in gender determination such as lip prints, mandibular canine index (MCI), fingerprints, and correlation between them. SUBJECTS AND METHODS: The pilot study group consisted of 300 samples aged between 18 and 25 years. Lip prints, fingerprints, and impressions of lower mandibular arches were collected. STATISTICAL ANALYSIS USED: The results were analyzed using Chi-square test for lip prints and fingerprints with an independent sample t-test for the MCI. Intergroup comparison between the parameters was analyzed by ANNOVA test. RESULTS: Type II lip print pattern and loop pattern of fingerprints were the predominant patterns in both males and females, and mesiodistal width of right MCI has greater sexual dimorphism than left MCI. CONCLUSIONS: Although lip prints, fingerprints, and MCI had their own specifications, correlation of the three parameters did not show any significance.

Novel biotransformation process of podophyllotoxin to 4 ß-sulfur-substituted podophyllum derivates with anti-tumor activity by Penicillium purpurogenum Y.J. Tang.

According to the structure-function relationship of podophyllotoxin (PTOX) and its analogue of 4'- demethylepipodophyllotoxin (DMEP), the 4 ß-substitution of sulfur-containing heterocyclic compounds with a carbon-sulfur bond at 4 position of PTOX or DMEP is an essential modification direction for improving the anti-tumor activity. So, four novel 4 ß-sulfursubstituted podophyllum derivatives (i.e., 4ß -(1,2,4-triazole-3-yl)sulfanyl-4-deoxy-podophyllotoxin (4-MT-PTOX), 4ß-(1,3,4- thiadiazole-2-yl)sulfanyl-4-deoxy-podophyllotoxin (4-MTD-PTOX), 4ß-(1,2,4-triazole-3-yl)sulfanyl-4-deoxy-4' -demethylepipodophyllotoxin (4-MT-DMEP), and 4ß-(1,3,4-thiadiazole-2-yl)sulfanyl-4-deoxy-4'-demethylepipodophyllotoxin (4-MTD-DMEP)) were designed and then successfully biosynthesized in this work. In the novel sulfur-substituted biotransformation processes, PTOX and DMEP was linked with sulfur-containing compounds (i.e., 3-mercapto-1,2,4-triazole (MT) and 2-mercapto-1,3,4-thiadiazole (MTD)) at 4 position of cycloparaffin to produce 4-MT-PTOX (1), 4-MTD-PTOX (2), 4-MT-DMEP (3), and 4-MTD-DMEP (4) by Penicillium purpurogenum Y.J. Tang, respectively, which was screened out from Diphylleia sinensis Li (Hubei, China). All the novel compounds exhibited promising in vitro bioactivity, especially 4-MT-PTOX (1). Compared with etoposide (i.e., a 50 % effective concentration [EC(50)] of 25.72, 167.97, and 1.15 M), the EC(50) values of 4-MT-PTOX (1) against tumor cell line BGC-823, A549 and HepG2 (i.e., 0.28, 0.76, and 0.42 M) were significantly improved by 91, 221 and 2.73 times, respectively. Moreover, the EC(50) value of 4-MT-PTOX (1) against the normal human cell line HK-2 (i.e., 182.4 µM) was 19 times higher than that of etoposide (i.e., 9.17 µM). Based on the rational design, four novel 4 ß-sulfur-substituted podophyllum derivatives with superior in vitro anti-tumor activity were obtained for the first time. The correctness of structure-function relationship and rational drug design was strictly demonstrated by the in vitro biological activity tests.