Nanosecond-pulsed plasma protects against bacterial fruit blotch and promotes melon seedling growth.

BACKGROUND: Bacterial fruit blotch (BFB), known as the 'cancer' of cucurbits, is a seed-borne disease of melons caused by Acidovorax citrulli. Traditional chemical treatments for BFB are ineffective and adversely affect the environment. Using dielectric barrier discharge (DBD) nanosecond-pulsed plasma technology, melon seeds were treated to promote germination and growth and to control BFB. RESULTS: Based on the evaluation parameters of seed germination, seedling growth, leaf yellowing and bacterial infection after seed plasma treatments, 9 min at 20 kV was selected as the optimal plasma discharge parameter. In this study, seedling growth was significantly improved after treating melon seeds carrying A. citrulli using this discharge parameter. The number of first true leaves measured on the eighth day was 2.3 times higher and the disease index was reduced by 60.5% compared to the control group. Attenuated total reflectance-Fourier transform infrared measurements show that plasma treatments penetrate the seed coat and denature polysaccharides and proteins in the seed kernel, affecting their growth and sterilization properties. CONCLUSION: Pre-sowing treatment of melon seeds carrying A. citrulli using nanosecond-pulsed plasma technology can effectively control seedling BFB disease and promote melon seedling growth by optimizing DBD parameters. © 2024 Society of Chemical Industry.

[Study on expression of LIM domain only protein 1 in SD rat oral buccal mucosa carcinogenesis induced by 4-nitro-quinoline N-oxide].

OBJECTIVE: This work aimed to determine the expression changes in LIM domain only protein 1 (LMO1) in gene transcription and protein levels during oral squamous cell carcinoma (OSCC) development. METHODS: The tissues in this study were taken from our team's previous animal model building, and we performed hematoxylin-eosin (HE) staining on 49 cases. The pathological classification of the experiment group was determined on the basis of the abnormal epithelial hyperplasia degree. The expression part of LMO1 was determined by immunohistochemistry staining. The mRNA and protein LMO1 expression levels in five groups were detected by real-time fluorescent quantitative of nucleotide polymer chain reaction (RT-qPCR) and Western blot, respectively. RESULTS: HE staining determined 7 cases of the control group, 6 cases of mild epithelial dysplasia, 11 cases of moderate epithelial dysplasia, 9 cases of severe epithelial dysplasia, and 16 cases of OSCC. Immunohistochemistry results: LMO1 expression was localized in the cytoplasm, and the positive expression rates of the protein LMO1 in the control and experiment groups were 14.3% for normal buccal mucosal tissue, 33.3% for mild epithelial dysplasia, 81.8% for moderate epithelial dysplasia, 88.9% for severe epithelial dysplasia, and 93.8% for OSCC. RT-qPCR results: mRNA expression was lowest in the control group and highest in the OSCC group, the difference between the mild dysplasia and control groups was not significant (P>0.05). Pairwise comparison among other groups showed statistically significant differences (P<0.05). Western blot results: with the aggravation of the pathological degree, the protein LMO1 expression level increased gradually. The OSCC group expressed the highest LMO1 expression level. CONCLUSIONS: The oral mucosa carcinogenesis models showed abnormal the mRNA and protein LMO1 expression levels, and the mRNA and protein expression levels were positively correlated with the degree of abnormal proliferation.

Characterization of different biodegradable scaffolds in tissue engineering.

The aim of the present study was to compare the characteristics of acellular dermal matrix (ADM), small intestinal submucosa (SIS) and Bio­Gide scaffolds with acellular vascular matrix (ACVM)­0.25% human­like collagen I (HLC­I) scaffold in tissue engineering blood vessels. The ACVM­0.25% HLC­I scaffold was prepared and compared with ADM, SIS and Bio­Gide scaffolds via hematoxylin and eosin (H&E) staining, Masson staining and scanning electron microscope (SEM) observations. Primary human gingival fibroblasts (HGFs) were cultured and identified. Then, the experiment was established via the seeding of HGFs on different scaffolds for 1, 4 and 7 days. The compatibility of four different scaffolds with HGFs was evaluated by H&E staining, SEM observation and Cell Counting Kit­8 assay. Then, a series of experiments were conducted to evaluate water absorption capacities, mechanical abilities, the ultra­microstructure and the cytotoxicity of the four scaffolds. The ACVM­0.25% HLC­I scaffold was revealed to exhibit the best cell proliferation and good cell architecture. ADM and Bio­Gide scaffolds exhibited good mechanical stability but cell proliferation was reduced when compared with the ACVM­0.25% HLC­I scaffold. In addition, SIS scaffolds exhibited the worst cell proliferation. The ACVM­0.25% HLC­I scaffold exhibited the best water absorption, followed by the SIS and Bio­Gide scaffolds, and then the ADM scaffold. In conclusion, the ACVM­0.25% HLC­I scaffold has good mechanical properties as a tissue engineering scaffold and the present results suggest that it has better biological characterization when compared with other scaffold types.

Surface pressure-dependent interactions of secretory phospholipase A2 with zwitterionic phospholipid membranes.

The hydrolytic activity of secretory phospholipase A(2) (PLA(2)) is regulated by many factors, including the physical state of substrate aggregates and the chemical nature of phospholipid molecules. In order to achieve strong binding of PLA(2) on its substrates, many previous works have used anionic lipid dispersion to characterize the orientation and penetration depth of PLA(2) molecules on membrane surfaces. In this study, we applied monolayer technique with controllable surface area to investigate the PLA(2)s of Taiwan cobra venom and bee venom on zwitterionic phophatidylcholine monolayers and demonstrated an optimum hydrolytic activity at a surface pressure of 18 and 24 mN/m, respectively. By combining polarized attenuated total reflection Fourier-transform infrared spectroscopy and monolayer-binding experiments, we found that the amount of membrane-bound PLA(2) decreased markedly as the surface pressure of the monolayer was increased. Interestingly, the insertion area of the PLA(2)s decreased to near zero as the surface pressure increased to the optimum pressure for hydrolytic activity. On the basis of the measured infrared dichroic ratio, the orientation of the PLA(2)s bound to zwitterionic membranes was similar to that observed on a negatively charged membrane and was independent of the surface pressure. Our findings suggest that both PLA(2)s were located on the membrane surface rather than penetrating the membrane bilayer and that the deeply inserted mode is not a favorable condition for the hydrolysis of phospholipids in zwitterionic phospholipid membranes. The results are discussed in terms of the easy access of catalytic water for the PLA(2) activity and the mobilization of its substrate and product to facilitate the catalytic process.