Expression of ethylene biosynthetic genes during flower senescence and in response to ethephon and silver nitrate treatments in Osmanthus fragrans.

BACKGROUND: Sweet osmanthus (Osmanthus fragrans) is an ornamental evergreen tree species in China, whose flowers are sensitive to ethylene. The synthesis of ethylene is controlled by key enzymes and restriction enzymes, 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), which are encoded by multigene families. However, the key synthase responsible for ethylene regulation in O. fragrans is still unknown. OBJECTIVE: This study aims to screen the key ethylene synthase genes of sweet osmanthus flowers in response to ethylene regulation. METHODS: In this study, we used the ACO and ACS sequences of Arabidopsis thaliana to search for homologous genes in the O. fragrans petal transcriptome database. These genes were also analyzed bioinformatically. Finally, the expression levels of O. fragrans were compared before and after senescence, as well as after ethephon and silver nitrate treatments. RESULTS: The results showed that there are five ACO genes and one ACS gene in O. fragrans transcriptome database, and the phylogenetic tree revealed that the proteins encoded by these genes had high homology to the ACS and ACO proteins in plants. Sequence alignment shows that the OfACO1-5 proteins have the 2OG-Fe(II) oxygenase domain, while OfACS1 contains seven conserved domains, as well as conserved amino acids in transaminases and glutamate residues related to substrate specificity. Expression analysis revealed that the expression levels of OfACS1 and OfACO1-5 were significantly higher at the early senescence stage compared to the full flowering stage. The transcripts of the OfACS1, OfACO2, and OfACO5 genes were upregulated by treatment with ethephon. However, out of these three genes, only OfACO2 was significantly downregulated by treatment with AgNO3. CONCLUSION: Our study found that OfACO2 is an important synthase gene in response to ethylene regulation in sweet osmanthus, which would provide valuable data for further investigation into the mechanisms of ethylene-induced senescence in sweet osmanthus flowers.

Eco-friendly approaches of zinc oxide and silver nitrate nanoparticles along with plant extracts against Spodoptera litura (Fabricius) under laboratory conditions.

The tobacco cutworm (Spodoptera litura) is a widespread pest that inflicts severe damage on various crops, including cotton, tobacco, and vegetables, with a particular preference for solanaceous plants. Traditional control methods often rely heavily on synthetic insecticides, leading to adverse effects on the environment, human health, and the development of insecticide resistance. In light of these challenges, this study explores the potential of nanotechnology as an innovative and sustainable approach to combat this notorious pest. Bioassays were conducted using laboratory-reared 3rd instar S. litura larvae. Eight different plant extracts coated with zinc oxide and silver nitrate nanoparticles were tested, with concentrations in both distilled water and ethanol at 3, 5, and 7 ml. Data were collected at 24, 48, and 72-h intervals. The results revealed that the highest larval mortality, reaching 98%, was observed in the group treated with silver nitrate nanoparticles derived from Cymbopogon citratus. In comparison, the group treated with zinc oxide nanoparticles dissolved in ethanol exhibited a larval mortality rate of 90%. Ethanol is a polar solvent that is widely used in the synthesis of nanocomposites. It is capable of forming strong hydrogen bonds with oxygen atoms, making it a good dispersant for zinc oxide nanoparticles. Additionally, ethanol has a low boiling point and a non-toxic nature, which makes it a safe and effective option for the dispersion of nanoparticles. Notably, the study concluded that silver nanoparticles combined with ethanol exhibited prolonged and more potent toxic effects against S. litura when compared to zinc oxide nanoparticles. Overall, this research underscores the potential of nanotechnology as a valuable component of Integrated Pest Management (IPM) strategies. By integrating nanotechnology into pest management practices, we can promote sustainable and environmentally friendly approaches that benefit both farmers and the ecosystem.

Synthesis and Characterization of Silver Nanoparticles from Rhizophora apiculata and Studies on Their Wound Healing, Antioxidant, Anti-Inflammatory, and Cytotoxic Activity.

Silver nanoparticles (AgNPs) have recently gained interest in the medical field because of their biological features. The present study aimed at screening Rhizophora apiculata secondary metabolites, quantifying their flavonoids and total phenolics content, green synthesis and characterization of R. apiculata silver nanoparticles. In addition, an assessment of in vitro cytotoxic, antioxidant, anti-inflammatory and wound healing activity of R. apiculata and its synthesized AgNPs was carried out. The powdered plant material (leaves) was subjected to Soxhlet extraction to obtain R. apiculata aqueous extract. The R. apiculata extract was used as a reducing agent in synthesizing AgNPs from silver nitrate. The synthesized AgNPs were characterized by UV-Vis, SEM-EDX, XRD, FTIR, particle size analyzer and zeta potential. Further aqueous leaf extract of R. apiculata and AgNPs was subjected for in vitro antioxidant, anti-inflammatory, wound healing and cytotoxic activity against A375 (Skin cancer), A549 (Lung cancer), and KB-3-1 (Oral cancer) cell lines. All experiments were repeated three times (n = 3), and the results were given as the mean ± SEM. The flavonoids and total phenolics content in R. apiculata extract were 44.18 ± 0.086 mg/g of quercetin and 53.24 ± 0.028 mg/g of gallic acid, respectively. SEM analysis revealed R. apiculata AgNPs with diameters ranging from 35 to 100 nm. XRD confirmed that the synthesized silver nanoparticles were crystalline in nature. The cytotoxicity cell viability assay revealed that the AgNPs were less toxic (IC50 105.5 µg/mL) compared to the R. apiculata extract (IC50 47.47 µg/mL) against the non-cancerous fibroblast L929 cell line. Antioxidant, anti-inflammatory, and cytotoxicity tests revealed that AgNPs had significantly more activity than the plant extract. The AgNPs inhibited protein denaturation by a mean percentage of 71.65%, which was equivalent to the standard anti-inflammatory medication diclofenac (94.24%). The AgNPs showed considerable cytotoxic effect, and the percentage of cell viability against skin cancer, lung cancer, and oral cancer cell lines was 31.84%, 56.09% and 22.59%, respectively. R. apiculata AgNPs demonstrated stronger cell migration and percentage of wound closure (82.79%) compared to the plant extract (75.23%). The overall results revealed that R. apiculata AgNPs exhibited potential antioxidant, anti-inflammatory, wound healing, and cytotoxic properties. In future, R. apiculata should be further explored to unmask its therapeutic potential and the mechanistic pathways of AgNPs should be studied in detail in in vivo animal models.

Anticancer, Enhanced Antibacterial, and Free Radical Scavenging Potential of Fucoidan- (Fucus vesiculosus Source) Mediated Silver Nanoparticles.

The present research displays the green synthesis of stable silver nanoparticles (AgNPs). The aqueous solution of Fucoidan from Fucus vesiculosus source (brown marine algae) is used as a reducing and capping agent. UV-Vis spectroscopy, XRD, FT-IR, SEM, EDX, and TEM with selected area electron diffraction are used to characterize the synthesized silver nanoparticles (AgNPs). The synthesized AgNPs exhibit a surface plasmon resonance at 430 nm after 24 h. The characterization results showed that AgNPs are crystalline in nature and exhibit mostly spherical shapes with an average diameter of 4-45 nm. Silver nanoparticles showed effective antibacterial activity against representative pathogens of bacteria. The activities of commercial antibiotics were enhanced by impregnation with the synthesized AgNPs. It also shows good fungicidal and anticancer activity against liver and lung cell lines and shows significant antioxidant efficacy (84%) at 10 µg/ml AgNP concentration against DPPH. The utilization of environmentally synthesized AgNPs offers numerous benefits of ecofriendliness and compatibility for biomedical applications.

Silver Nanoparticle-Anchored Human Hair Kerateine/PEO/PVA Nanofibers for Antibacterial Application and Cell Proliferation.

The main core of wound treatment is cell growth and anti-infection. To accelerate the proliferation of fibroblasts in the wound and prevent wound infections, various strategies have been tried. It remains a challenge to obtain good cell proliferation and antibacterial effects. Here, human hair kerateine (HHK)/poly(ethylene oxide) (PEO)/poly(vinyl alcohol) (PVA) nanofibers were prepared using cysteine-rich HHK, and then, silver nanoparticles (AgNPs) were in situ anchored in the sulfur-containing amino acid residues of HHK. After the ultrasonic degradation test, HHK/PEO/PVA nanofibrous mats treated with 0.005-M silver nitrate were selected due to their relatively complete structures. It was observed by TEM-EDS that the sulfur-containing amino acids in HHK were the main anchor points of AgNPs. The results of FTIR, XRD and the thermal analysis suggested that the hydrogen bonds between PEO and PVA were broken by HHK and, further, by AgNPs. AgNPs could act as a catalyst to promote the thermal degradation reaction of PVA, PEO and HHK, which was beneficial for silver recycling and medical waste treatment. The antibacterial properties of AgNP-HHK/PEO/PVA nanofibers were examined by the disk diffusion method, and it was observed that they had potential antibacterial capability against Gram-positive bacteria, Gram-negative bacteria and fungi. In addition, HHK in the nanofibrous mats significantly improved the cell proliferation of NIH3T3 cells. These results illustrated that the AgNP-HHK/PEO/PVA nanofibrous mats exhibited excellent antibacterial activity and the ability to promote the proliferation of fibroblasts, reaching our target applications.

Nanopartículas de prata em bases de próteses de PMMA para controle de atividade microbiana / Silver nanoparticles in PMMA prosthesis bases to control microbial activity

Objetivo:Avaliar in vitro a atividade de Staphylococcus aureus e Candida albicans em bases de próteses convencionais à base de polimetilmetacrilato de metila com nanopartículas de prata incorporadas a sua composição. Métodos: Foi realizado um estudo experimental laboratorial com resinas acrílicas autopolimerizáveis comercialmente disponíveis, Vipi Flash/VIPI e JET/Clássico. Foram confeccionados 80 corpos de prova, divididos em 16 grupos (n = 5), referentes ao tipo de resina, tratamento (incorporação e imersão na solução de nanopartículas de prata) e microrganismo inoculado. As nanopartículas foram sintetizadas com ácido polimetacrílico, nitrato de prata e irradiadas com luz ultravioleta de baixa potência (~8W) por 6 horas, e as suas concentrações idealizadas pelo método de microdiluição em placas para determinação da concentração mínima inibitória frente aos microrganismos selecionados. Verificou-se ação bactericida e fungicida com concentração inicial de 25% e após fator de diluição 12,5%. Resultados: Houve dificuldade de incorporação das nanopartículas na resina acrílica, que pode decorrer da alteração da proporção 3:1 recomendada pelo fabricante ou pela redução ou inativação da ação da nanopartícula de prata pela interação com o polimetilmetacrilato. VIPI com inclusão de nanopartícula obteve menor aderência de biofilme de Candida albicans. Conclusão:A nanopartícula de prata mostrou-se eficaz na sua ação de controle de Candida albicans e Staphylococcus aureus no método de imersão, entretanto, a sua ação antimicrobiana foi comprometida após inclusão nas resinas acrílicas.

Aim:To perform an in vitro evaluation of the activity of Staphylococcus aureus and Candida albicansin conventional prosthesis bases, based on methyl polymethylmethacrylate with silver nanoparticles incorporated into the composition. Methods: An experimental laboratory study was carried out using commercially available self-curing acrylic resins, Vipi Flash/VIPI and JET/Clássico. Eighty specimens were manufactured and divided into 16 groups (n = 5), referent to the resin brand, treatment (incorporation and immersion in the silver nanoparticle solution), and inoculated microorganism. The nanoparticles were synthesized with polymethacrylic acid and silver nitrate, and were irradiated with a low power (~ 8W) ultraviolet light for 6 hours. Their concentrations were idealized by the method of microplate dilution to determine the minimum inhibitory concentration when compared to the selected microorganisms. Bactericidal and fungicidal activities were identified with an initial concentration of 25% and a subsequent dilution factor of 12.5%. Results:It was difficult to incorporate the AgNPs into the acrylic resin, which may well have resulted from the change from the 3:1 proportion recommended by the manufacturer or by reducing or inactivating the action of the silver nanoparticle by interaction with polymethylmethacrylate. VIPI with the inclusion of nanoparticles obtained a lesser Candida albicans biofilm adherence. Conclusion: Silver nanoparticles were effective in controlling Candida albicans and Staphylococcus aureus in the immersion method; however, the antimicrobial activity was compromised after inclusion in acrylic resins.

Green synthesis of silver nanoparticles using Indian Belladonna extract and their potential antioxidant, anti-inflammatory, anticancer and larvicidal activities.

KEY MESSAGE: Atropa acuminata aqueous leaf extract biosynthesized silver nanoparticles showed strong antioxidant, anticancerous (HeLa cells) and anti-inflammatory activities. Besides, this bio syn-AgNP also proved effective against mosquito vectors causing malaria, dengue and filariasis. Present study highlights eco-friendly and sustainable approach for the synthesis of silver nanoparticles (AgNP) using aqueous leaf extract of A. acuminata, a critically endangered medicinal herb. The addition of 1 mM silver nitrate to aqueous leaf extract resulted in the synthesis of AgNP when solution was heated at 60 °C for 30 min at pH 7. Absorption band at 428 nm, as shown by UV-Vis spectroscopy confirmed the synthesis of AgNP. XRD patterns revealed the crystalline nature of AgNP and TEM analysis showed that most of the nanoparticles were spherical in shape. Zeta potential of AgNP was found to be - 33.5 mV which confirmed their high stability. FT-IR investigations confirmed the presence of different functional groups involved in the reduction and capping of AgNP. The synthesized AgNP showed effective DPPH (IC50-16.08 µg/mL), H2O2 (IC50-25.40 µg/mL), and superoxide (IC50-21.12 µg/mL) radical scavenging activities. These plant-AgNP showed significant inhibition of albumin denaturation (IC50-12.98 µg/mL) and antiproteinase activity (IC50-18.401 µg/mL). Besides, biosynthesized AgNP were found to have strong inhibitory effect against a cervical cancer (HeLa) cell line (IC50-5.418 µg/mL) as well as larvicidal activity against 3rd instar larvae of Anopheles stephensi (LC50-18.9 ppm, LC90-40.18 ppm), Aedes aegypti (LC50-12.395 ppm, LC90-36.34 ppm) and Culex quinquefasciatus (LC50-17.76 ppm, LC90-30.82 ppm) and were found to be non-toxic against normal cell line (HEK 293), and a non-target organism (Mesocyclops thermocyclopoides). This is the first report on the synthesis of AgNP using aqueous leaf extract of A. acuminata, validating their strong therapeutic potential.

The Effect of Oral Consumption of Propolis Alone and in Combination With Silver Nanoparticles on Wound Healing in Male Wistar Rats.

Research to identify and develop compounds that facilitate wound healing is important, especially for hard-to-heal chronic wounds. PURPOSE: This study was conducted to investigate the effects of orally administered propolis (a resinous substance found in beehives), alone and in combination with silver nanoparticles (SNPs), on the wound healing process in male rats. METHODS: Forty (40) male Wistar rats were randomly divided into 4 groups of 10 each: 1 control group received no treatment, and 3 study groups received a daily dose of 1) propolis (100 mg/kg), 2) propolis + 30 ppm SNPs, or 3) propolis + 60 ppm SNPs. Healing rate was determined by wound surface area reduction on days 4, 6, 8, and 10 post-surgery. On day 12 after wound creation, histological changes of wound healing, including number of new vessels, inflammatory cells (neutrophils, eosinophils, and mast cells) and fibroblasts were counted based on morphology using a 400x objective lens, and collagen deposition density was determined using hematoxylin and eosin and trichrome staining, respectively. The histological scores were based on a 0 to 4 scale from lowest to highest amount of improving tissue status and were analyzed using one-way analysis of variance, Tukey test, Kruskal-Wallis test, t test, and Mann-Whitney U test to examine differences among the groups. Significance was set at P <.05. RESULTS: The rate of wound healing was significantly different between the control and the treated groups on days 4, 6, 8, and 10 (percent change was not assessed on day 12) post-surgery, especially in the propolis + 30 ppm SNPs group compared to the control group. This difference was more significant on days 6 (wound healing percentage [WHP]: 75% and 45%) and 8 (WHP: 88% and 65% ) post-surgery (P <.001). Mean neutrophil count on day 12 was highest in the control (34.8 ± 2.97) and lowest in the propolis + 30 ppm SNPs group (16.55 ± 2.12). The number of eosinophils on day 12 was considerably higher in the control group (1.05 ± 4) compared to those in the propolis group (3 ± 0.70), propolis + 30 ppm SNPs group (60/0 ± 1/1), and propolis + 60 ppm SNPs group (0.5 ± 0.52) (P <.001). Mean propolis + 30 ppm SNPs scores for epithelialization and granulation tissue formation were 3 and 4, respectively; in the propolis + 60 ppm SNPs, scores were 2 and 3, respectively; in the propolis alone group scores were 2 and 3, respectively (statistical significance not computed for semiquantitative values). The highest fibroblast count was in the propolis + 30 ppm SNPs group (114.44 ± 3.90) compared to control group (73.2 ± 2.8); P <.001). The difference in collagen fiber density scores was also significant: 1.2 ± 0.42 in the control and 3.66 ± 0.50 in the propolis + 30 ppm SNPs group; (P <.001). The mean of collagen fiber density in the propolis + 60 ppm SNPs group was 2.63 ± 0.51. CONCLUSION: Oral propolis alone and in combination with 30 ppm SNPs appears to provide anti-inflammatory effects and increase fibroblast proliferation and collagen deposition in experimental wounds, which may explain the observed differences in healing. Propolis + 60 ppm SNPs appears to have a cytotoxic effect. Research confirming these results and that examines toxicity levels in animals and humans is needed.

Comparative and Mechanistic Study on the Anticancer Activity of Quinacrine-Based Silver and Gold Hybrid Nanoparticles in Head and Neck Cancer.

Using oral cancer cells ( in vitro) and in vivo xenograft mice model, we have systematically studied the detailed mechanism of anticancer activity of quinacrine-based hybrid silver (QAgNP) and gold (QAuNP) nanoparticles (NPs) and compared their efficacies. Both the NPs showed characteristic anti-cell proliferation profile in various cancer cells with minimally affecting the normal nontransformed breast epithelial MCF-10A cells. The IC50 values of QAuNP in various cancer cells were less compared to QAgNP and also found to be the lowest (0.5 µg/mL) in SCC-9 oral cancer cells. Although both NPs caused apoptosis by increased DNA damage, arresting at S phase and simultaneously inhibiting the DNA repair activity in cells, efficacy of QAuNP was better than that of QAgNP. NPs intercalated with DNA and inhibited the topoisomerase activity in cells. Alteration in expression of cell cycle regulatory (cyclins B1, E1, A2, etc.) and replication-related (MRE11, RPA, RFC, etc.) proteins were also observed after NP exposure to the cells. Accumulation of cells resulted in extended G/M phase after prolonged exposure of QAuNP in SCC-9 cells. Interestingly, depletion of geminin and increase of Cdt-1 along with CDC-6 suggest the formation of re-replication. Recovery of body weight and reduction in tumor volume were found in NP-treated xenograft mice. Induction of Bax/Bcl-xL, PARP-1 cleavage, p53, and p21 were noted in NP-treated xenograft mice tissue samples. Thus, data suggest that NP inhibits topoisomerase activity, thereby inhibiting DNA replication and inducing re-replication, which causes S-phase arrest, DNA damage, and finally apoptosis of the oral cancer cells. Also, it was found that anticancer activity of QAuNP is better than that of QAgNP.

In vitro evaluation of the protoscolicidal effect of Eucalyptus globulus essential oil on protoscolices of hydatid cyst compared with hypertonic saline, povidone iodine and silver nitrate.

OBJECTIVE: There are various protoscolicidal agents for inactivation of protoscoleces of hydatid cysts before and during surgical operation. The present study was aimed to evaluate the protoscolicidal effect of two concentrations of Eucalyptus globulus on protoscoleces of Echinococcus granulosus sensu lato under in vitro condition and to compare its efficacy with hypertonic saline, povidone iodine and silver nitrate. METHODS: Live protoscoleces obtained from the liver of naturally infected sheep were exposed to 0.5% and 1% of Eucalyptus globulus essential oil, 5% hypertonic saline, 10% povidone iodine and 0.5% silver nitrate for 1 and 3minutes. Phosphate buffered saline was used as a negative control. One percent eosin staining method was used to test the viability of protoscoleces in different groups. RESULTS: While the mean percentage of dead protoscoleces was 6.08% in the control group, the scolicidal power of 5% hypertonic saline was only 6.54% and 6.60% after 1 and 3min respectively. 0.5% E. globulus EO demonstrated 97.38% and 100% scolicidal activity after 1 and 3min respectively. The mean protoscolicidal power of 1% E. globulus EO, 10% povidone iodine and 0.5% silver nitrate was 100% after one minute. CONCLUSIONS: According to the results of this study, E. globulus EO demonstrated high scolicidal power in a short period of time. Hence, this herbal product could be considered as a potent natural scolicidal agent that could be used before and during surgery of hydatid disease.

Pyrrole-Hemoglobin Adducts, a More Feasible Potential Biomarker of Pyrrolizidine Alkaloid Exposure.

Pyrrolizidine alkaloids (PAs) are naturally occurring phytotoxins widely distributed in about 3% of flowering plants. The formation of PA-derived pyrrole-protein adducts is considered as a primary trigger initiating PA-induced hepatotoxicity. The present study aims to (i) further validate our previous established derivatization method using acidified ethanolic AgNO3 for the analysis of pyrrole-protein adducts and (ii) apply this method to characterize the binding tendency, dose-response, and elimination kinetics of pyrrole-protein adducts in blood samples. Two pyrrole-amino acid conjugates, (±)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5 H-pyrrolizine (DHP)-cysteine (7-cysteine-DHP) and 9-histidine-DHP, were synthesized and used to demonstrate that acidified ethanolic AgNO3 derivatization can cleave both S-linkage and N-linkage of pyrrole-protein adducts. Subsequently, using precolumn AgNO3 derivatization followed by ultra-high-pressure liquid chromatography/mass spectrometry analysis, we quantified pyrrole-protein adducts in monocrotaline-treated rat blood protein fractions, including hemoglobin (Hb), plasma, albumin, and plasma residual protein fractions, and found that the amount of pyrrole-Hb adducts was significantly higher than that in all plasma fractions. Moreover, elimination half-life of pyrrole-Hb adducts was also significantly longer than pyrrole-protein adducts in plasma fractions (12.08 vs 2.54-2.93 days). In addition, we also tested blood samples obtained from five PA-induced liver injury patients and found that the amount of pyrrole-protein adducts in blood cells was also remarkably higher than that in plasma. In conclusion, our findings for the first time confirmed that the AgNO3 derivatization method could be used to measure both S- and N-linked pyrrole-protein adducts and also suggested that pyrrole-Hb adducts with remarkably higher level and longer life span could be a better biomarker of PA exposure.

Synthesis, characterization, antibacterial activity in dark and in vitro cytocompatibility of Ag-incorporated TiO2 microspheres with high specific surface area.

Postoperative infection associated with medical implants is a devastating complication of orthopedic surgery. Considering the difficulties for the diagnosis and treatment of infection, coating the implant material with antibacterial substances is a promising protocol by which to avoid such an adverse reaction. Nanoparticles (NPs) constructed of anatase microspheres, one form of titanium dioxide (TiO2), with a high specific surface area are fabricated in this study in a facile one-step process using homogeneous precipitation at 90 °C under atmospheric pressure using titanium sulfate (Ti[SO4]2) and urea as the titanium source and precipitant, respectively. The molar ratio of silver (Ag) to TiO2 can be changed by varying the amount of silver nitrate (AgNO3). The high specific surface area of the TiO2 microspheres combined with Ag particles (Ag/TiO2) exhibit excellent antibacterial properties against both Staphylococcus aureus and Escherichia coli. In addition, the Ag/TiO2 material in this work possesses satisfactory biological performance on MC3T3-E1 cells. The high specific surface area of Ag/TiO2 together with good antibacterial properties and cytocompatibility provide promising applications in dentistry, orthopedics, and other fields of medicine that use biomedical devices.

Comparative effects of ethylene inhibitors on Agrobacterium-mediated transformation of drought-tolerant wild watermelon.

Ethylene (C2H4), a phytohormone that is produced in response to both abiotic and biotic stresses, is an important factor influencing the efficiency of Agrobacterium-mediated transformation. In this study, effects of various ethylene inhibitors on the efficiency of Agrobacterium-mediated genetic transformation in drought-tolerant wild watermelon was comparatively examined. Consequently, in comparison to the application of chemical inhibitors such as AgNO3 and aminoethoxyvinylglycine (AVG), lower ethylene level was observed when the infecting Agrobacterium contained a gene for 1-aminocyclopropane-carboxylic acid (ACC) deaminase (acdS), which cleaves ethylene precursor ACC into α-ketobutyrate and ammonia. GUS histochemical and spectrophotometric enzyme assays showed that acdS was more effective in enhancing gene transfer than the chemical ethylene inhibitors. Efficiency of transgenic shoots formation was higher in acdS- and AVG-treated explants. These observations demonstrated that controlling the ethylene level during co-cultivation and shoot formation, particularly using the acdS-harboring Agrobacterium, is advantageous for enhancing the transformation efficiency in this plant.

Role of ethylene and related gene expression in the interaction between strawberry plants and the plant growth-promoting bacterium Azospirillum brasilense.

Induced systemic resistance (ISR) is one of the indirect mechanisms of growth promotion exerted by plant growth-promoting bacteria, and can be mediated by ethylene (ET). We assessed ET production and the expression of related genes in the Azospirillum-strawberry plant interaction. Ethylene production was evaluated by gas chromatography in plants inoculated or not with A. brasilense REC3. Also, plants were treated with AgNO3 , an inhibitor of ET biosynthesis; with 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor of ET biosynthesis; and with indole acetic acid (IAA). Plant dry biomass and the growth index were determined to assess the growth-promoting effect of A. brasilense REC3 in strawberry plants. Quantitative real time PCR (qRT-PCR) was performed to analyse relative expression of the genes Faetr1, Faers1 and Faein4, which encode ET receptors; Factr1 and Faein2, involved in the ET signalling pathway; Faacs1 encoding ACC synthase; Faaco1 encoding ACC oxidase; and Faaux1 and Faami1 for IAA synthesis enzymes. Results showed that ET acts as a rapid and transient signal in the first 12 h post-treatment. A. brasilense REC3-inoculated plants had a significantly higher growth index compared to control plants. Modulation of the genes Faetr1, Faers1, Faein4, Factr1, Faein2 and Faaco1 indicated activation of ET synthesis and signalling pathways. The up-regulation of Faaux1 and Faami1 involved in IAA synthesis suggested that inoculation with A. brasilense REC3 induces production of this auxin, modulating ET signalling. Ethylene production and up-regulation of genes associated with ET signalling in strawberry plants inoculated with A. brasilense REC3 support the priming activation characteristic of ISR. This type of resistance and the activation of systemic acquired resistance previously observed in this interaction indicate that both are present in strawberry plants, could act synergistically and increase protection against pathogens.

Distinct Mechanisms of Biotic and Chemical Elicitors Enable Additive Elicitation of the Anticancer Phytoalexin Glyceollin I.

Phytoalexins are metabolites biosynthesized in plants in response to pathogen, environmental, and chemical stresses that often have potent bioactivities, rendering them promising for use as therapeutics or scaffolds for pharmaceutical development. Glyceollin I is an isoflavonoid phytoalexin from soybean that exhibits potent anticancer activities and is not economical to synthesize. Here, we tested a range of source tissues from soybean, in addition to chemical and biotic elicitors, to understand how to enhance the bioproduction of glyceollin I. Combining the inorganic chemical silver nitrate (AgNO3) with the wall glucan elicitor (WGE) from the soybean pathogen Phytophthora sojae had an additive effect on the elicitation of soybean seeds, resulting in a yield of up to 745.1 µg gt-1 glyceollin I. The additive elicitation suggested that the biotic and chemical elicitors acted largely by separate mechanisms. WGE caused a major accumulation of phytoalexin gene transcripts, whereas AgNO3 inhibited and enhanced the degradation of glyceollin I and 6″-O-malonyldaidzin, respectively.

Growth process and anticancer properties of gold nanorods.

Gold nanoparticles have been of great interest because of their unique optical properties, facile synthesis and conjugation. Among various shapes of gold nanoparticles, gold nanorods have been widely studied. They can be conjugated with different molecules for biomedical applications, such as tumor imaging and therapy. However, few researchers have studied the antitumor properties of bare gold nanorods. In this study, unfunctionalized gold nanorods were synthesized and tested on breast tumor cells. Results showed that the aspect ratio of gold nanorods could be easily influenced by both reaction time and the amount of silver nitrate in the growth solution. A new growth process is proposed here based on the UV-Vis spectra and TEM images of gold nanorods at different reaction times. More importantly, cell studies showed that within a certain concentration range, the gold nanorods can selectively kill tumor cells while having limited or little influence on healthy mammalian (dermal fibroblast) cells. Thus, this study shows promise for the use of bare gold nanorods for further study alone or in combination with photothermal treatment. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2616-2621, 2017.

The apoptotic and genomic studies on A549 cell line induced by silver nitrate.

Lung cancer is the leading cause of male cancer deaths worldwide. Metal-based anticancer drugs have evolved significantly during the past decades. Recently, silver ions have been investigated for their anticancer effects. We aimed to study the time-course cytotoxic effects of silver nitrate on A549 adenocarcinomic human alveolar basal epithelial cells to provide insights into the molecular-level understanding of growth suppression mechanism involved in apoptosis. The influences of silver nitrate were studied via MTT assay, flow cytometry, immunocytochemical, confocal and transmission electron microscopy, and microarray assays. Silver nitrate showed inhibitory effects against A549 cells in a dose- and time-dependent manner for 24, 48, and 72 h and induced apoptosis. The early and late apoptotic cells and depolarized mitochondrial membrane potential were determined by the half-maximal inhibitory concentration (IC50) value of silver nitrate treated for 72 h. But cysteinyl aspartate proteinase-3 was not activated for 72 h. Furthermore, IC50 value of silver nitrate also induced apoptosis according to immunocytochemical assays for 72 h. The downregulated CCNY, HNRNPL, ASF1B, PIAS4, HNRNPH1, EIF2C2, TAF15, FOXC1, LEP, and PCB2 genes administered with silver nitrate IC50 were identified as apoptosis-leading genes. Silver nitrate may be a suitable therapeutic agent against lung cancer.

Silver nanoparticles synthesized and coated with pectin: An ideal compromise for anti-bacterial and anti-biofilm action combined with wound-healing properties.

The synthesis of Ag nanoparticles from Ag+ has been investigated, with pectin acting both as reductant and coating.∼100% Ag+ to Ag(0) one-pot conversion was obtained, yielding p-AgNP, i.e. an aqueous solution of pectin-coated spherical Ag nanoparticles (d=8.0±2.6nm), with a<1ppm concentration of free Ag+ cation. Despite the low free Ag+ concentration and low Ag+ release with time, the nature of the coating allows p-AgNP to exert excellent antibacterial and antibiofilm actions, comparable to those of ionic silver, tested on E. coli (Gram-) and S. epidermidis (Gram+) both on planctonic cells and on pre- and post-biofilm formation conditions. Moreover, p-AgNP were tested on fibroblasts: not only p-AgNP were found to be cytocompatible but also revealed capable of promoting fibroblasts proliferation and to be effective for wound healing on model cultures. The antibacterial activity and the wound healing ability of silver nanoparticles are two apparently irreconcilable properties, as the former usually requires a high sustained Ag+ release while the latter requires low Ag+ concentration. p-AgNP represents an excellent compromise between opposite requirements, candidating as an efficient medication for repairing wounds and/or to treat vulnerable surgical site tissues, including the pre-treatment of implants as an effective prophylaxis in implant surgery.

Silver Nitrate Interpreted as Osseous Pathology on RadiographsTwo Case Reports.

Silver nitrate is often used topically for hemostasis. When radiography is performed after the application of silver nitrate, an artifact appears on the radiograph that may be mistaken for an abnormal calcification or a foreign body. The patients in the following two cases were treated with topical silver nitrate. In each case, radiographs taken after treatment seemed to demonstrate abnormal soft-tissue calcifications in the area of silver nitrate application. Subsequent clinical examination revealed no calcifications, and it was determined that the abnormal radiographic findings were silver nitrate artifacts. Although this phenomenon has been described in the medical literature, misdiagnosis still occurs and could potentially lead to additional imaging or unnecessary procedures.