Chitosan, Gelatin, and Collagen Hydrogels for Bone Regeneration.

Hydrogels are versatile biomaterials characterized by three-dimensional, cross-linked, highly hydrated polymeric networks. These polymers exhibit a great variety of biochemical and biophysical properties, which allow for the diffusion of diverse molecules, such as drugs, active ingredients, growth factors, and nanoparticles. Meanwhile, these polymers can control chemical and molecular interactions at the cellular level. The polymeric network can be molded into different structures, imitating the structural characteristics of surrounding tissues and bone defects. Interestingly, the application of hydrogels in bone tissue engineering (BTE) has been gathering significant attention due to the beneficial bone improvement results that have been achieved. Moreover, essential clinical and osteoblastic fate-controlling advances have been achieved with the use of synthetic polymers in the production of hydrogels. However, current trends look towards fabricating hydrogels from biological precursors, such as biopolymers, due to the high biocompatibility, degradability, and mechanical control that can be regulated. Therefore, this review analyzes the concept of hydrogels and the characteristics of chitosan, collagen, and gelatin as excellent candidates for fabricating BTE scaffolds. The changes and opportunities brought on by these biopolymers in bone regeneration are discussed, considering the integration, synergy, and biocompatibility features.

A Triazaspirane Derivative Inhibits Migration and Invasion in PC3 Prostate Cancer Cells.

Cancer is a serious health problem due to the complexity of establishing an effective treatment. The purpose of this work was to evaluate the activity of a triazaspirane as a migration and invasion inhibitor in PC3 prostatic tumor cells through a possible negative regulation of the FAK/Src signal transduction pathway and decreased secretion of metalloproteinases 2 and 9. Molecular docking analysis was performed using Moe 2008.10 software. Migration (wound-healing assay) and invasion (Boyden chamber assay) assays were performed. In addition, the Western blot technique was used to quantify protein expression, and the zymography technique was used to observe the secretion of metalloproteinases. Molecular docking showed interactions in regions of interest of the FAK and Src proteins. Moreover, the biological activity assays demonstrated an inhibitory effect on cell migration and invasion, an important suppression of metalloproteinase secretion, and a decrease in the expression of p-FAK and p-Src proteins in treated PC3 cells. Triazaspirane-type molecules have important inhibitory effects on the mechanisms associated with metastasis in PC3 tumor cells.

Atherosclerotic-Derived Endothelial Cell Response Conducted by Titanium Oxide Nanotubes.

Atherosclerosis lesions are described as the formation of an occlusive wall-vessel plaque that can exacerbate infarctions, strokes, and even death. Furthermore, atherosclerosis damages the endothelium integrity, avoiding proper regeneration after stent implantation. Therefore, we investigate the beneficial effects of TiO2 nanotubes (NTs) in promoting the initial response of detrimental human atherosclerotic-derived endothelial cells (AThEC). We synthesized and characterized NTs on Ti6Al4V by anodization. We isolated AThEC and tested the adhesion long-lasting proliferation activity, and the modulation of focal adhesions conducted on the materials. Moreover, ultrastructural cell-surface contact at the nanoscale and membrane roughness were evaluated to explain the results. Our findings depicted improved filopodia and focal adhesions stimulated by the NTs. Similarly, the NTs harbored long-lasting proliferative metabolism after 5 days, explained by overcoming cell-contact interactions at the nanoscale. Furthermore, the senescent activity detected in the AThEC could be mitigated by the modified membrane roughness and cellular stretch orchestrated by the NTs. Importantly, the NTs stimulate the initial endothelial anchorage and metabolic recovery required to regenerate the endothelial monolayer. Despite the dysfunctional status of the AThEC, our study brings new evidence for the potential application of nano-configured biomaterials for innovation in stent technologies.

Recovering Osteoblast Functionality on TiO2 Nanotube Surfaces Under Diabetic Conditions.

Introduction: Titanium (Ti) and its alloys (eg, Ti6Al4V) are exceptional treatments for replacing or repairing bones and damaged surrounding tissues. Although Ti-based implants exhibit excellent osteoconductive performance under healthy conditions, the effectiveness and successful clinical achievements are negatively altered in diabetic patients. Concernedly, diabetes mellitus (DM) contributes to osteoblastic dysfunctionality, altering efficient osseointegration. This work investigates the beneficial osteogenic activity conducted by nanostructured TiO2 under detrimental microenvironment conditions, simulated by human diabetic serum. Methods: We evaluated the bone-forming functional properties of osteoblasts on synthesized TiO2 nanotubes (NTs) by anodization and Ti6Al4V non-modified alloy surfaces under detrimental diabetic conditions. To simulate the detrimental environment, MC3T3E-1 preosteoblasts were cultured under human diabetic serum (DS) of two diagnosed and metabolically controlled patients. Normal human serum (HS) was used to mimic health conditions and fetal bovine serum (FBS) as the control culture environment. We characterized the matrix mineralization under the detrimental conditions on the control alloy and the NTs. Moreover, we applied immunofluorescence of osteoblasts differentiation markers on the NTs to understand the bone-expression stimulated by the biochemical medium conditions. Results: The diabetic conditions depressed the initial osteoblast growth ability, as evidenced by altered early cell adhesion and reduced proliferation. Nonetheless, after three days, the diabetic damage was suppressed by the NTs, enhancing the osteoblast activity. Therefore, the osteogenic markers of bone formation and the differentiation of osteoblasts were reactivated by the nanoconfigured surfaces. Far more importantly, collagen secretion and bone-matrix mineralization were stimulated and conducted to levels similar to those of the control of FBS conditions, in comparison to the control alloy, which was not able to reach similar levels of bone functionality than the NTs. Conclusion: Our study brings knowledge for the potential application of nanostructured biomaterials to work as an integrative platform under the detrimental metabolic status present in diabetic conditions.

Micropropagation of Seed-Derived Clonal Lines of the Endangered Agave marmorata Roezl and Their Compatibility with Endophytes.

A. marmorata is the raw material used for tepextate mescal production but is classified as an endangered species. In the present study, we obtain and multiply clonal lines of Agave marmorata Roezl by selecting seedlings derived from seeds. Ten seedlings from two lots of 400 germinated seeds were selected for axillary bud proliferation induced by BAP 5 mg/L in vitamin-free Murashige and Skoog's medium. Differences in shoot numbers, heights and senescent tissue formation were observed. Notably, the AM32 line formed 84 shoots and presented low senescent tissue after 60 d of culture. We also selected the AM31 and AM33 clonal lines. Four-month shoots were extracted with 80% methanol in water to determine the total content of saponins, flavonoids, and phenolic acids and compare the three clonal lines. Some bioactive molecules were identified using HPLC techniques and MALDI-TOF mass spectrometry none showed significant differences in content. Additionally, plants derived from the clonal lines were inoculated with four endophytic bacteria. Among these, Achromobacter xylosoxidans supported plant growth of AM32. A notable effect of plant death was observed after inoculation with Enterobacter cloacae, an endophyte of A. tequilana. Additionally, Pseudomonas aeruginosa, an endophyte from A. marmorata, reduced biomass. Our results demonstrate the incompatibility of A. marmorata to E. cloacae and specialization between the host plant and its endophytes. The compatibility of the plant-endophyte could be exploited to boost the establishment and stability of mutualisms to benefit plant development, stress tolerance and pathogen resistance. The differences in multiplication capacity, stable tissue formation, and endophyte biotization responses may indicate genetic variability. Clonal selection and micropropagation from seed-derived plants could contribute to conserving the endangered A. marmorata plant for reforestation in their natural habitats, thus, assuring mass propagation for sustainable industrial production of mescal, bioactive compounds, and prebiotics.

New Bacillus subtilis Strains Isolated from Prosopis glandulosa Rhizosphere for Suppressing Fusarium Spp. and Enhancing Growth of Gossypium hirsutum L.

Rhizobacteria from desert plants can alleviate biotic stress and suppress plant diseases, and consequently can enhance plant growth. Therefore, the current study was performed to isolate and identify Prosopis glandulosa-associating rhizobacteria based on their antagonistic activity against Fusarium species and plant growth-promoting properties. Three bacterial isolates were identified as Bacillus subtilis: LDA-1, LDA-2, and LDA-3. The molecular analysis suggests the biosynthesis of the bacteriocins subtilisin and subtilosin, as well as the lipopeptide iturin, by these strains. In addition, the antagonistic study by dual-culture assay showed a high efficacy of all B. subtilis strains against phytopathogenic fungi (Fusarium nygamai, F. equisseti, F. solani, F. solani ICADL1, and F. oxysporum ICADL2) with inhibition percentages ranging from 43.3 to 83.5% in comparison to the control. Moreover, atomic force microscopy (AFM) analysis showed significant differences in the cell wall topography of the F. solani ICADL1 among the treated mycelia and untreated control. As a result, these three B. subtilis strains were used as bioinoculants for cotton seedlings infected by F. solani ICADL1 in pot trials, and the results revealed that the bacterial inoculations as an individual or combined with F. solani ICADL1 significantly improved cotton root and stem length, lateral roots, indole acetic acid (IAA), and gibberellic acid (GA3) contents, as well as increased antioxidants, flavonoids, and phenols in comparison to those obtained from healthy and infected control plants. In conclusion, the three bacterial strains of B. subtilis (i.e., LDA-1, LDA-2, and LDA-3) are considered promising tools as biocontrol agents for F. solani and cotton growth promoters, and consequently can be used as bio-ertilizer in sustainable agriculture systems.

Feasibility of Using H3PO4/H2O2 in the Synthesis of Antimicrobial TiO2 Nanoporous Surfaces.

Ti6Al4V alloys are the primary materials used for clinical bone regeneration and restoration; however, they are substantially susceptible to biomaterial-related infections. Therefore, in the present work, we applied a controllable and stable oxidative nanopatterning strategy by applying H3PO4, a weaker dissociating acid, as a substitute for H2SO4 in the classical piranha reaction. The results suggest that our method acted as a concomitant platform to develop reproducible diameter-controlled TiO2 nanopores (NPs). Interestingly, our procedure illustrated stable temperature reactions without exothermic responses since the addition of mixture preparation to the nanopatterning reactions. The reactions were carried out for 30 min (NP14), 1 h (NP7), and 2 h (NP36), suggesting the formation of a thin nanopore layer as observed by Raman spectroscopy. Moreover, the antimicrobial activity revealed that NP7 could disrupt active microbial colonization for 2 h and 6 h. The phenotype configuration strikingly showed that NP7 does not alter the cell morphology, thus proposing a disruptive adhesion pathway instead of cellular lysis. Furthermore, preliminary assays suggested an early promoted osteoblasts viability in comparison to the control material. Our work opens a new path for the rationale design of nanobiomaterials with "intelligent surfaces" capable of decreasing microbial adhesion, increasing osteoblast viability, and being scalable for industrial transfer.

Probiotic Endophytes for More Sustainable Banana Production.

Climatic factors and pathogenic fungi threaten global banana production. Moreover, bananas are being cultivated using excessive amendments of nitrogen and pesticides, which shift the microbial diversity in plants and soil. Advances in high-throughput sequencing (HTS) technologies and culture-dependent methods have provided valuable information about microbial diversity and functionality of plant-associated endophytic communities. Under stressful (biotic or abiotic) conditions, plants can recruit sets of microorganisms to alleviate specific potentially detrimental effects, a phenomenon known as "cry for help". This mechanism is likely initiated in banana plants infected by Fusarium wilt pathogen. Recently, reports demonstrated the synergistic and cumulative effects of synthetic microbial communities (SynComs) on naturally occurring plant microbiomes. Indeed, probiotic SynComs have been shown to increase plant resilience against biotic and abiotic stresses and promote growth. This review focuses on endophytic bacterial diversity and keystone taxa of banana plants. We also discuss the prospects of creating SynComs composed of endophytic bacteria that could enhance the production and sustainability of Cavendish bananas (Musa acuminata AAA), the fourth most important crop for maintaining global food security.

Azadirachta indica Leaf Extract as Green Corrosion Inhibitor for Reinforced Concrete Structures: Corrosion Effectiveness against Commercial Corrosion Inhibitors and Concrete Integrity.

The construction industry has extensively demanded novel green inhibition strategies for the conservation and protection of carbon steel-reinforced concrete structures. For the first time, the effect of Azadirachta indica leaf extract (Neem) as a potential corrosion inhibitor of carbon steel in reinforced concrete under corrosion in saline simulated media was evaluated. To assess the corrosion inhibition behavior of the Neem natural organic extract, three inorganic commercial inhibitors were tested to compare following the criteria established by Stratful for half-cell potential under a simulated chloride environment. Moreover, the effect of concrete integrity by the Neem treatment was recorded after different temperature conditions, slump, weight alteration, air content, compressive strength, and chloride-ions penetration. The results suggested that the Neem treatments did not alter the concrete integrity and the physicochemical parameters. We reached a promoted long-term corrosion protection of 95% after 182 days of evaluation. Thus far, our current results open up a new promising "green" road to the conservation of carbon steel in reinforced concrete for the construction industry.

Crystallographic Pattern Mediates Fungal Nanoadhesion Bond Formation on Titanium Nanotubes.

The development of nanoadhesion bonds at the cell-material biointerface has been considered as a current prospective mechanism of microbial adhesion and colonization. However, there is a tremendous lack of evidence for the rational design of outstanding antifungal nanoconfigured materials. Therefore, extending our previous insights of evidence, we found that blocking the adhesion and biofilm formation of Candida albicans on NTs requires the inhibition of fungal nanoadhesion bonds. This work reports a concept for understanding the antifungal behavior of the crystallographic phase for anatase (NTs-annealed) and amorphous NTs. Herein, we demonstrated that the crystallographic orientation is a predominant parameter to reduce C. albicans, over the surface roughness and chemistry. We showed that the anatase phase conducted to an invasive phenotype, cellular envelopment insertion, followed by the improved cellular spread. Meanwhile, the amorphous configuration imposed reduced nanoadhesion bonds mainly appreciated over the mouths of the NTs, as revealed by cross sectioning. Moreover, our results showed that under fungal conditions, the experimental materials could reduce the surface energy. This work highlights that the crystallographic pattern predominantly controls the antifungal activity of NTs. The evaluated systems proposed that the NTs-annealed conducted an optimized insertion of fungal cells. Nonetheless, amorphous NTs inhibited the deposition of C. albicans via blocking the insertion and the development of nanoadhesion bonds, without morphology aberrations. The present discoveries can further inspire the rational design of upgraded nanoconfigured surfaces with noteworthy antifungal characteristics for antimicrobial coating technologies.

Promotion of Surgical Masks Antimicrobial Activity by Disinfection and Impregnation with Disinfectant Silver Nanoparticles.

BACKGROUND: The COVID-19 pandemic is requesting highly effective protective personnel equipment, mainly for healthcare professionals. However, the current demand has exceeded the supply chain and, consequently, shortage of essential medical materials, such as surgical masks. Due to these alarming limitations, it is crucial to develop effective means of disinfection, reusing, and thereby applying antimicrobial shielding protection to the clinical supplies. PURPOSE: Therefore, in this work, we developed a novel, economical, and straightforward approach to promote antimicrobial activity to surgical masks by impregnating silver nanoparticles (AgNPs). METHODS: Our strategy consisted of fabricating a new alcohol disinfectant formulation combining special surfactants and AgNPs, which is demonstrated to be extensively effective against a broad number of microbial surrogates of SARS-CoV-2. RESULTS: The present nano-formula reported a superior microbial reduction of 99.999% against a wide number of microorganisms. Furthermore, the enveloped H5N1 virus was wholly inactivated after 15 min of disinfection. Far more attractive, the current method for reusing surgical masks did not show outcomes of detrimental amendments, suggesting that the protocol does not alter the filtration effectiveness. CONCLUSION: The nano-disinfectant provides a valuable strategy for effective decontamination, reuse, and even antimicrobial promotion to surgical masks for frontline clinical personnel.

Poly(N-vinylcaprolactam) and Salicylic Acid Polymeric Prodrug Grafted onto Medical Silicone to Obtain a Novel Thermo- and pH-Responsive Drug Delivery System for Potential Medical Devices.

New medical devices with anti-inflammatory properties are critical to prevent inflammatory processes and infections in medical/surgical procedures. In this work, we present a novel functionalization of silicone for medical use with a polymeric prodrug and a thermosensitive polymer, by graft polymerization (gamma rays), for the localized release of salicylic acid, an analgesic, and anti-inflammatory drug. Silicone rubber (SR) films were functionalized in two stages using graft polymerization from ionizing radiation (60Co). The first stage was grafting poly(N-vinylcaprolactam) (PNVCL), a thermo-sensitive polymer, onto SR to obtain SR-g-PNVCL. In the second stage, poly(2-methacryloyloxy-benzoic acid) (P2MBA), a polymeric prodrug, was grafted to obtain (SR-g-PNVCL)-g-P2MBA. The degree of functionalization depended on the concentrations of monomers and the irradiation dose. The films were characterized by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDX), thermogravimetric analysis (TGA), and contact angle. An upper critical solution temperature (UCST) of the films was demonstrated by the swelling degree as a temperature function. (SR-g-PNVCL)-g-P2MBA films demonstrated hydrolysis-mediated drug release from the polymeric prodrug, pH, and temperature sensitivity. GC-MS confirmed the presence of the drug (salicylic acid), after polymer hydrolysis. The concentration of the drug in the release media was quantified by HPLC. Cytocompatibility and thermo-/pH sensitivity of functionalized medical silicone were demonstrated in cancer and non-cancer cells.

Structure-activity relationship of diameter controlled Ag@Cu nanoparticles in broad-spectrum antibacterial mechanism.

Current outbreaks associated with drug-resistant clinical strains are demanding for the development of broad-spectrum antibacterial agents. The bactericidal materials should be eco-friendly, economical and effective to suppress bacterial growth. Thus, in this work, diameter controlled spherical Cucore-Agshell nanoparticles (Ag@CuNPs) with diameter ranging from 70 to 100 nm by one-step co-reduction approach were designed and synthesized. The Ag@CuNPs were homogenous, stable, and positively charged. The 70 nm Ag@CuNPs showed a consistent and regular Ag shielding. We observed the 100 nm Ag@CuNPs achieved symmetrical doped Ag clusters on the Cu core surface. We used Gram-positive and Gram-negative models strains to test the wide-spectrum antibacterial activity. The Ag@CuNPs showed detrimental microbial viability in a dose-dependent manner; however, 70 nm Ag@CuNPs were superior to those of 100 nm Ag@CuNPs. Initially, Ag@CuNPs attached and translocated the membrane surface resulting in bacterial eradication. Our analyses exhibited that antibacterial mechanism was not governed by the bacterial genre, nonetheless, by cell type, morphology, growing ability and the NPs uptake capability. The Ag@CuNPs were highly tolerated by human fibroblasts, mainly by the use of starch as glucosidic capper and stabilizer, suggesting optimal biocompatibility and activity. The Ag@CuNPs open up a novel platform to study the potential action of bimetallic nanoparticles and their molecular role for biomedical, clinical, hospital and industrial-chemical applications.

Changes in the physiological and biochemical state of peanut plants (Arachis hypogaea L.) induced by exposure to green metallic nanoparticles.

Different types of nanoparticles (NPs) are increasingly used in multiple sectors such as industry, medicine and agriculture. This application has increased the possibility of NPs accumulating and contaminating the environment. Plants are one of the essential building blocks of all ecosystems and the interaction between NPs and plants is an indispensable aspect of risk assessment. To understand the effects of NPs in agricultural systems, in the present study we investigated the effects of exposure of Ag, Cu and Cu/Ag phytonanoparticles in Arachis hypogaea L. plants at a physiological and biochemical level, for which NPs solutions were applied foliarly at concentrations of 250, 500, 750 and 1000 ppm for 48 days. Parameters such as leaf length, chlorophyll and concentration of phytohormones showed that phytonanoparticles could cause serious damage to plant growth and development. Plants exposed to phytonanoparticles showed an increase in total phenols, proline, PAL activity and antioxidant enzymes, this to mitigate the stress caused. The alteration in the composition and content of fatty acids in the peanut kernels after exposure to different NPs indicated that they could affect the yield and quality of crop. Therefore, it is necessary to investigate its potential impact on food quality. Statement of noveltyIn this manuscript, we report for the first time that green nanoparticles induced a lower degree of toxicity in plants compared to commercial nanoparticles.Our results indicate that the mechanisms by which peanut plants respond to the application of nanoparticles were an increase in the activity of phenylalanine ammonia-lyase and antioxidant enzymes. So far there are few studies on the effect of nanoparticles on plant hormones, our results revealed a significant decrease in indole-3 acetic acid and induced the synthesis of gibberellins. The modification in the composition and content of fatty acids in the peanut kernels indicated that the nanoparticles could affect the quality of the crop.

Nutritional assessment, phytochemical composition and antioxidant analysis of the pulp and seed of medjool date grown in Mexico.

The aim of this study was the characterization of fatty acids, antioxidant activity, some physical properties, nutrient content, sugars, and minerals in the pulp and seeds of the date cultivar 'Medjool' (Phoenix dactylifera L.) grown in Mexico. The samples were obtained at maturity (Tamar) in the 2017 harvest season in the valleys of San Luis Rio Colorado and Mexicali, Mexico. The following average values were obtained on a % dry weight basis for pulp and seeds, respectively: protein, 3.14% and 4.84%; lipids, 0.75% and 9.94%; fiber, 6.34% and 66.79%; total sugars, 75.32% and 5.88%; reducing sugars, 70.26% and 4.40%; and sucrose, 5.06% and 1.46%. Analysis of the minerals revealed that the most abundant elements for the pulp were: potassium, 851.98 mg/100 g; magnesium, 142.97 mg/100 g; and phosphorus, 139.40 mg/100 g, whereas for the seeds, they were potassium, 413.36 mg/100 g; sulfur, 151.36 mg/100 g; and phosphorus, 92.42 mg/100 g. Gas chromatography-mass spectrometry analysis revealed that the major unsaturated fatty acid was oleic acid, at 52.34% and 45.92%, respectively, for pulp and seeds. The main saturated fatty acids were palmitic acid (6.75%) and lauric acid (17.24%) in pulp and seeds, respectively. The total phenolic content was 1.16 and 13.73 mg GAE/100 g for pulp and seeds, respectively. Finally, the antioxidant activities were: b-carotene, 65.50% and 47.75%; DPPH, 0.079 IC50 g/L and 0.0046 IC50 g/L; and ABTS, 13.72 IC50 g/L and 0.238 IC50 g/L, respectively. The results obtained in this study confirm that the 'Medjool' cultivar grown in Mexico has the same quality of nutrients and antioxidants as those grown in the other main date-producing countries.

Nanopartículas de plata de Justicia spicigera y sus potencialidades antimicrobianas en el control biológico de bacterias transmitidas por alimentos y hongos fitopatógenos / Silver nanoparticles from Justicia spicigera and their antimicrobial potentialities in the biocontrol of foodborne bacteria and phytopathogenic fungi

In the present work, the biosynthesis of silver-nanoparticles (AgNP) was evaluated using the aqueous extract from Justicia spicigera. The obtained silver nanoparticles were characterized using UV-visible spectroscopic techniques, energy dispersive X-ray spectrometers (EDS), zeta potential and dynamic light scattering. The antimicrobial activity of biosynthesized AgNP was tested against foodborne bacteria (Bacillus cereus, Klebsiella pneumoniae and Enterobacter aerogenes) and phytopathogenic fungi (Colletotrichum sp., Fusarium solani, Alternaria alternata and Macrophomina phaseolina). The elemental profile of synthesized nanoparticles using J. spicigera shows higher counts at 3 keV due to silver, confirming the formation of silver nanoparticles. Scanning electron microscopy (SEM) analysis showed a particle size between 86 and 100 nm with spherical morphology. AgNP showed effective antibacterial and antifungal activity against the tested organisms principally with B. cereus, K. pneumoniae, E. aerogenes, A. alternata and M. phaseolina. Therefore, further studies are needed to confirm the potential of AgNP from J. spicigera in the control of indicator organisms under field conditions.

En el presente trabajo se evaluó la biosíntesis de nanopartículas de plata (AgNP) en presencia de una sal de plata y extractos acuosos de Justicia spicigera. Las nanopartículas así obtenidas fueron caracterizadas mediante técnicas espectroscópicas UV-visibles, espectrómetros de rayos X de energía dispersiva (EDS), potencial zeta y dispersión de luz dinámica. La actividad antimicrobiana de las AgNP biosintetizadas se probó frente a diversas bacterias transmitidas por alimentos (Bacillus cereus, Klebsiella pneumoniae y Enterobacter aerogenes) y hongos fitopatógenos (Colletotrichum sp., Fusarium solani, Alternaria alternata y Macrophomina phaseolina). El perfil elemental de las nanopartículas sintetizadas utilizando el extracto de J. spicigera mostró valores altos a 3 keV, lo que confirma la formación de nanopartículas de plata. El análisis por microscopía electrónica de barrido (SEM) reveló un tamaño de partícula entre 86 y 100 nm, con morfología esférica. Las AgNP mostraron una actividad antibacteriana y antifúngica efectiva contra los organismos evaluados, principalmente contra B. cereus, K. pneumoniae, E. aerogenes, A. alternata y M. phaseolina. Se necesitan más estudios para confirmar el potencial de las AgNP derivadas de J. spicigera en el control de organismos indicadores en condiciones de campo.

Enterobacter cloacae, an Endophyte That Establishes a Nutrient-Transfer Symbiosis With Banana Plants and Protects Against the Black Sigatoka Pathogen.

Banana (Musa spp.) is an important crop worldwide, but black Sigatoka disease caused by the fungus Pseudocercospora fijiensis threatens fruit production. In this work, we examined the potential of the endophytes of banana plants Enterobacter cloacae and Klebsiella pneumoniae, as antagonists of P. fijiensis and support plant growth in nutrient limited soils by N-transfer. The two bacterial isolates were identified by MALDI-TOF mass spectrometry and corroborated by 16S rRNA sequence analysis. Both bacteria were positive for beneficial traits such as N-fixation, indole acetic acid production, phosphate solubilization, negative for 1-aminocyclopropane 1-carboxylic acid deaminase and were antagonistic to P. fijiensis. To measure the effects on plant growth, the two plant bacteria and an E. coli strain (as non-endophyte), were inoculated weekly for 60 days as active cells (AC) and heat-killed cells (HKC) into plant microcosms without nutrients and compared to a water only treatment, and a mineral nutrients solution (MMN) treatment. Bacterial treatments increased growth parameters and prevented accelerated senescence, which was observed for water and mineral nutrients solution (MMN) treatments used as controls. Plants died after the first 20 days of being irrigated with water; irrigation with MMN enabled plants to develop some new leaves, but plants lost weight (-30%) during the same period. Plants treated with bacteria showed good growth, but E. cloacae AC treated plants had significantly greater biomass than the E. cloacae HKC. After 60 days, plants inoculated with E. cloacae AC showed intracellular bacteria within root cells, suggesting that a stable symbiosis was established. To evaluate the transference of organic N from bacteria into the plants, the 3 bacteria were grown with 15NH4Cl or Na15NO3 as the nitrogen source. The 15N transferred from bacteria to plant tissues was measured by pheophytin isotopomer abundance. The relative abundance of the isotopomers m/z 872.57, 873.57, 874.57, 875.57, 876.57 unequivocally demonstrated that plants acquired 15N atoms directly from bacterial cells, using them as a source of N, to support plant growth in restricted nutrient soils. E. cloacae might be a new alternative to promote growth and health of banana crops.

Correction: Ungson, Y. et al. Filling of Irregular Channels with Round Cross-Section: Modeling Aspects to Study the Properties of Porous Materials. Materials 2018, 11, 1901.

The authors have found two errors in the paper published in Materials [...].

Controlled antifungal behavior on Ti6Al4V nanostructured by chemical nanopatterning.

Infections associated with bone implant prostheses are mainly related to bacterial contaminations. Recent investigations have suggested an important role of opportunistic fungal cells associated with non-responding antibacterial treatments. Thus, in order to evaluate the early Candida albicans (C. albicans) behavior; we built on Ti6Al4V surfaces nanopores (NPs) with controlled diameters applying oxidative nanopatterning for 30 (NP30) and 60 min (NP60). As a result of nanopatterning NPs with diameters of 12 and 24 nm were synthesized. Physicochemical differences were observed between both types of NPs, the most highlighting of which are anatase phase formation and improved hydrophilicity of NP60. C. albicans adhesion and colonization was assessed using scanning electron microscopy and by yeast counting for viability evaluation. The fungal behavior on the substrates was significantly different, showing an initial exopolysaccharide secretion stimulated by the nanopatterned surfaces. Larger NPs led to an important reduction in viability with decreased cell-surface contact bonds. The obtained results demonstrate that special control in the fabrication of nanostructured TiO2 materials can improve the early fungal resistance, especially for dental implants.

Silver nanoparticles from Justicia spicigera and their antimicrobial potentialities in the biocontrol of foodborne bacteria and phytopathogenic fungi.

In the present work, the biosynthesis of silver-nanoparticles (AgNP) was evaluated using the aqueous extract from Justicia spicigera. The obtained silver nanoparticles were characterized using UV-visible spectroscopic techniques, energy dispersive X-ray spectrometers (EDS), zeta potential and dynamic light scattering. The antimicrobial activity of biosynthesized AgNP was tested against foodborne bacteria (Bacillus cereus, Klebsiella pneumoniae and Enterobacter aerogenes) and phytopathogenic fungi (Colletotrichum sp., Fusarium solani, Alternaria alternata and Macrophomina phaseolina). The elemental profile of synthesized nanoparticles using J. spicigera shows higher counts at 3keV due to silver, confirming the formation of silver nanoparticles. Scanning electron microscopy (SEM) analysis showed a particle size between 86 and 100nm with spherical morphology. AgNP showed effective antibacterial and antifungal activity against the tested organisms principally with B. cereus, K. pneumoniae, E. aerogenes, A. alternata and M. phaseolina. Therefore, further studies are needed to confirm the potential of AgNP from J. spicigera in the control of indicator organisms under field conditions.