Biohardening of Arabidopsis thaliana seeds and seedlings with fraser photinia associated bacterium (PGB_invit) in in vitro conditions

The aim of this study was to analyze possible positive effects of putatively endophytic PGPB (PGB_invit), which was isolated from long-term in vitro cultured fraser photinia microshoots, on seed and 7-day old seedling stages of Arabidopsis thaliana. Seeds and in vitro-germinated seedlings were inoculated with 10(7) CFU/mL and 10(8) CFU/mL active (A) and inactive (I) endophytic bacterial populations along with their mix compositions (A+I) and suspended in MPYE broth together with their controls (untreated ones). 14 days old seedlings were evaluated for various plant growth parameters [i.e., shoot and root fresh weight (FW), shoot length (SL), shoot and root dry weight (DW), root length (RL) and photosynthetic pigments including chlorophyll a, b and carotenoids of plantlets] as well as endophytic and rhizospheric trait of bacteria. Positive effects of inactive and active bacterium on FW, DW and photosynthetic pigments for 7-day inoculated seedlings were recorded whereas an increase in photosynthetic contents for seed stage inoculations was observed. Rhizospheric and endophytic colonization of the bacteria was confirmed by PCR with the presence of virD1 gene, which is previously recorded to be existed in the plasmid of bacterium after inoculation (Seker et al., 2017). Overall, these results demonstrated that this peculiar putative endophytic bacterium being beneficial in active and even more useful in inactive form for A. thaliana when optimum conditions and concentrations are used. Moreover, presence of virD1 gene suggested its potential possibility to be used in bioengineering along with various other beneficial PGPR features as biofertilizer

Synthesis of nZVI/PVP nanoparticles for bioremediation applications

The objective of this investigation is to synthesize and investigate zero-valent iron (ZVI) nanoparticles (NPs) for bioremediation applications. The ZVI-NPs were fabricated by chemical reduction using a ferrous salt solution with poly(N-vinylpyrrolidone) (PVP), used as a stabilizer. The synthesis was conducted with and without ultrasonic treatment. The ZVI NPs were fabricated and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) analysis, and Fourier Transform Infrared Spectroscopy (FTIR). Experimental observations demonstrate that depending on synthesis conditions and coordination of stabilizers, NPs with different morphologies are formed. Colloidal solutions of the synthesized NPs were used in antimicrobial activity tests and biofilm formation assays for nine different control microorganisms: Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 15692), Enterococcus faecalis (ATCC 29122), Klebsiella pneumoniae (laboratory isolates), Proteus vulgaris (laboratory isolates), Staphylococcus aureus (ATCC 29213), Bacillus cereus (DSMZ 4312), Bacillus subtilis (ATCC 6633), and Candida albicans (ATCC 10231). All control strains did not show antibacterial effect against PVP-stabilized ZVI NPs synthesized without ultrasonic treatment. However, biofilm results show that the highest absorbance values of the micro-organisms were tested in control wells. Although B. subtilis, E. coli, and K. pneumoniae were observed during biofilm formation, B. cereus, S. aureus, and P. aeruginosa biofilm formation reduced noticeably by Fe-0/PVP-US (A1) NPs. For control strains, such as E. faecalis and C. albicans, no biofilm formation was observed. For Fe-0/PVP (A2) NPs, biofilm formation of B. subtilis, E. faecalis, E. coli, K. pneumoniae, P. vulgaris, and C. albicans demonstrated positive effect, and B. cereus, S. aureus, P. aeruginosa showed negative effect. A strategic utilization of nZVI-PVP nanoparticles showed a great potential for effective, efficient, and sustainable bioremediation applications.SPINTECH project [810144]; joint operational programme, Romania -Republic of Moldova (2014-20) - ENI-CBC (Cross-Border Cooperation-European Neighborhood Instrument) [2SOFT/1.2/139]; [65/22.10.19A]The work is done in framework of the project no. 65/22.10.19A, titled Nanostructuri s, i nanomateriale funciionale pentru industrie s, i agricultura, with partial support from the SPINTECH project, under grant agreement no. 810144. This research was also funded with partial support under joint grant Contract no. 2SOFT/1.2/139 of joint operational programme, Romania -Republic of Moldova (2014-20), financed by ENI-CBC (Cross-Border Cooperation-European Neighborhood Instrument).WOS:0006417906000012-s2.0-8510472141

Synthesis of nZVI/PVP nanoparticles for bioremediation applications

The objective of this investigation is to synthesize and investigate zero-valent iron (ZVI) nanoparticles (NPs) for bioremediation applications. The ZVI-NPs were fabricated by chemical reduction using a ferrous salt solution with poly(N-vinylpyrrolidone) (PVP), used as a stabilizer. The synthesis was conducted with and without ultrasonic treatment. The ZVI NPs were fabricated and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) analysis, and Fourier Transform Infrared Spectroscopy (FTIR). Experimental observations demonstrate that depending on synthesis conditions and coordination of stabilizers, NPs with different morphologies are formed. Colloidal solutions of the synthesized NPs were used in antimicrobial activity tests and biofilm formation assays for nine different control microorganisms: Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 15692), Enterococcus faecalis (ATCC 29122), Klebsiella pneumoniae (laboratory isolates), Proteus vulgaris (laboratory isolates), Staphylococcus aureus (ATCC 29213), Bacillus cereus (DSMZ 4312), Bacillus subtilis (ATCC 6633), and Candida albicans (ATCC 10231). All control strains did not show antibacterial effect against PVP-stabilized ZVI NPs synthesized without ultrasonic treatment. However, biofilm results show that the highest absorbance values of the micro-organisms were tested in control wells. Although B. subtilis, E. coli, and K. pneumoniae were observed during biofilm formation, B. cereus, S. aureus, and P. aeruginosa biofilm formation reduced noticeably by Fe-0/PVP-US (A1) NPs. For control strains, such as E. faecalis and C. albicans, no biofilm formation was observed. For Fe-0/PVP (A2) NPs, biofilm formation of B. subtilis, E. faecalis, E. coli, K. pneumoniae, P. vulgaris, and C. albicans demonstrated positive effect, and B. cereus, S. aureus, P. aeruginosa showed negative effect. A strategic utilization of nZVI-PVP nanoparticles showed a great potential for effective, efficient, and sustainable bioremediation applications.SPINTECH project [810144]; joint operational programme, Romania -Republic of Moldova (2014-20) - ENI-CBC (Cross-Border Cooperation-European Neighborhood Instrument) [2SOFT/1.2/139]; [65/22.10.19A]The work is done in framework of the project no. 65/22.10.19A, titled Nanostructuri s, i nanomateriale funciionale pentru industrie s, i agricultura, with partial support from the SPINTECH project, under grant agreement no. 810144. This research was also funded with partial support under joint grant Contract no. 2SOFT/1.2/139 of joint operational programme, Romania -Republic of Moldova (2014-20), financed by ENI-CBC (Cross-Border Cooperation-European Neighborhood Instrument).WOS:0006417906000012-s2.0-8510472141