Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 75
Filtrar
1.
Antonie Van Leeuwenhoek ; 117(1): 63, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38561518

RESUMO

Phage resistance is crucial for lactic acid bacteria in the dairy industry. However, identifying all phages affecting these bacteria is challenging. CRISPR-Cas systems offer a resistance mechanism developed by bacteria and archaea against phages and plasmids. In this study, 11 S. thermophilus strains from traditional yogurts underwent analysis using next-generation sequencing (NGS) and bioinformatics tools. Initial characterization involved molecular ribotyping. Bioinformatics analysis of the NGS raw data revealed that all 11 strains possessed at least one CRISPR type. A total of 21 CRISPR loci were identified, belonging to CRISPR types II-A, II-C, and III-A, including 13 Type II-A, 1 Type III-C, and 7 Type III-A CRISPR types. By analyzing spacer sequences in S. thermophilus bacterial genomes and matching them with phage/plasmid genomes, notable strains emerged. SY9 showed prominence with 132 phage matches and 30 plasmid matches, followed by SY12 with 35 phage matches and 25 plasmid matches, and SY18 with 49 phage matches and 13 plasmid matches. These findings indicate the potential of S. thermophilus strains in phage/plasmid resistance for selecting starter cultures, ultimately improving the quality and quantity of dairy products. Nevertheless, further research is required to validate these results and explore the practical applications of this approach.


Assuntos
Bacteriófagos , Streptococcus thermophilus , Streptococcus thermophilus/genética , Sistemas CRISPR-Cas , Iogurte , Bacteriófagos/genética , Plasmídeos/genética
2.
Arch Microbiol ; 206(3): 121, 2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38400998

RESUMO

Yogurt, a globally consumed fermented dairy product, is recognized for its taste and potential health benefits attributed to probiotic bacteria, particularly Streptococcus thermophilus. In this study, we employed Multilocus Sequence Typing (MLST) to investigate the genetic diversity and phylogenetic relationships of 13 S. thermophilus isolates from traditional Turkish yogurt samples. We also assessed potential correlations between genetic traits and geographic origins. The isolates were identified as S. thermophilus using VITEK® MALDI-TOF MS, ribotyping, and 16S rRNA analysis methods. MLST analysis revealed 13 different sequence types (STs), with seven new STs for Turkey. The most prevalent STs were ST/83 (n = 3), ST/135 (n = 2), and ST/134 (n = 2). eBURST analysis showed that these isolates mainly were singletons (n = 7) defined as sequence types (STs) that cannot be assigned to any group and differ at two or more alleles from every other ST in the sample. This information suggests that the isolates under study were genetically distinct from the other isolates in the dataset, highlighting their unique genetic profiles within the population. Genetic diversity analysis of ten housekeeping genes revealed polymorphism, with some genes showing higher allelic variation than others. Tajima's D values suggested that selection pressures differed among these genes, with some being more conserved, likely due to their vital functions. Phylogenetic analysis revealed distinct genetic diversity between Turkish isolates and European and Asian counterparts. These findings demonstrate the genetic diversity of S. thermophilus isolates in Turkish yogurt and highlight their unique evolutionary patterns. This research contributes to our understanding of local microbial diversity associated with yogurt production in Turkey and holds the potential for identifyic strains with enhanced functional attributes.


Assuntos
Streptococcus thermophilus , Iogurte , Tipagem de Sequências Multilocus/métodos , Streptococcus thermophilus/genética , Filogenia , RNA Ribossômico 16S/genética , Turquia , Polimorfismo Genético , Variação Genética
3.
Int J Biol Macromol ; 245: 125520, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37353118

RESUMO

This study aimed to the production of inulinase and fructooligosaccharides (FOSs) from carob under the solid-state fermentation (SSF) conditions by using Plackett-Burman Design (PBD). Based on the results the maximum inulinase and specific inulinase activities were 249.98 U/mL and 318.29 U/mg protein, respectively. When the fructooligosaccharide (FOS) results were evaluated, the maximum values of 1,1,1-Kestopentaose, 1,1-Kestotetraose, and 1-Kestose were 182.01, 506.16, 132.16 ppm while the lowest and highest total FOS values were 179.35 and 516.66 ppm, respectively. On the other hand, it was observed that the maximum inulinase activity was found at the center points of the design. Therefore, validation fermentations were carried out at center point conditions. Subsequently, the yielded bulk enzyme extracts were partially purified using Spin-X UF membranes with 10, 30, and 50 kDa cut-off values. After purification, the maximum inulinase activity was 247.30 U/mg using a 50 kDa cut-off value. Followed by this process, the purified enzyme was used to produce FOSs and the results indicated that the maximum total FOS amount was 28,712.70 ppm. Consequently, this study successfully demonstrates that Aspergillus niger A42 inulinase produced from carob under the SSF conditions can be used in FOSs production.

4.
Environ Monit Assess ; 195(6): 719, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37222851

RESUMO

Erosion by water is the main cause of land degradation. Landscapes degraded by erosion need to be restored in many respects, and particularly in terms of ecosystem services. From an economic and management perspective, care is needed to select priority areas and determine the means to be applied to restore them. Globally, the model most commonly used to produce scenarios for the prevention of soil losses is the Revised Universal Soil Loss Equation (RUSLE). This study of the subbasin of the Sulakyurt Dam Basin in Turkey aims (1) to identify the distribution of soil losses over time and by location, and (2) to grade the priority areas for the prevention of soil losses by means of a simulation. The average potential soil losses in the area under study are estimated at 42.35 t ha-1 year-1, and the average actual losses at 39.49 t ha-1 year-1. According to the simulation, 27.61% of the study area (2782 ha) is of the highest priority for soil restoration. In our study, forests have the highest soil losses, which is contrary to the natural protection that forests provide against erosion. The high rates are due to the slope, the forest area is very steep. So it is the slope factor that outweighs the vegetation cover factor. Of the forest areas, 41.74% (1766 ha) falls within the areas of highest priority. The study serves as a guide for landscape planning and the determination of erosion risk in restoration efforts, and for identifying the methods to be adopted during the restoration work to reduce the loss of soil.


Assuntos
Ecossistema , Sistemas de Informação Geográfica , Monitoramento Ambiental , Simulação por Computador , Solo
5.
Animals (Basel) ; 14(1)2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38200762

RESUMO

In this study, the use of an ecological bridge installed as a wildlife overpass and constructed in the Zeytinler neighborhood in 2020 was analyzed as a mitigating factor in wild-boar-vehicle collisions (WVCs) on the Izmir-Çesme motorway. In this context, this study aimed to assess the use of the Zeytinler Ecological Bridge by wild boars (Sus scrofa Linnaeus, 1758). To this end, wildlife crossings were monitored, analyzed, and modeled with Bayesian networks. Between August 2020 and December 2022, a total of 686 instances of movement were observed among six medium to large wild mammal species. Wild boars accounted for approximately 87.5% of the recorded wildlife crossings, with foxes comprising 10%. The findings showed that the highest frequency of wildlife crossings occurred during the autumn season, particularly between 22:00 (10 p.m.) and 02:00 (2 a.m.), coinciding with the Waxing Gibbous and Waxing Crescent phases of the moon. The model outcomes highlighted that during the autumn season with a full pond, wild boar crossings increased by one and a half times in comparison to regular herd crossings. Throughout the observation period, there were no instances of wild boar fatalities subsequent to the completion of the bridge.

6.
Bioprocess Biosyst Eng ; 45(12): 2019-2029, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36329267

RESUMO

Hyaluronic acid (HA), a mucopolysaccharide belonging to the glycosaminoglycan family, consists of repeating disaccharide units and has been used directly or indirectly in numerous human health practices. This study focused on evaluating carob pods for microbial HA production and kinetic modeling of HA fermentation. Therefore, the optimal medium composition was determined using Plackett-Burman Design (PBD) for HA production from carob extract with Streptococcus zooepidemicus. Maximum HA production of shake flask fermentation was 2.6 g/L (1.25 × 106) in the optimum medium, comprising 10°Bx of carob pods extract, 0.5 g/L of MgSO4.7H2O, 10.0 g/L of casein, 2.5 g/L of KH2PO4, 2.0 g/L of NaCl, 1.5 g/L of K2HPO4, 0.002 g/L of FeSO4 and 10.0 g/L of beef extract. In the continuation of the study, the fermentation performed with the optimal medium composition was modeled using three different models including the logistic model for biomass production, the Luedeking-Piret model for HA production, and the modified Luedeking-Piret model for substrate consumption. Based on the results, the experimental HA production data agreed with the Luedeking-Piret model with an R2 of 0.989. Since the α value was 63-fold higher than the value of ß, the HA production is growth-associated. Consequently, carob extract can be evaluated as a promising carbon source for producing HA.


Assuntos
Streptococcus equi , Bovinos , Animais , Humanos , Ácido Hialurônico , Galactanos , Fermentação , Extratos Vegetais , Meios de Cultura/química
7.
Cureus ; 14(3): e23493, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35345813

RESUMO

BACKGROUND: Cannabis (marijuana) is one of the most abused drugs worldwide. The increasing availability of cannabis has been associated with increased emergency department (ED) visits. There is a wide range of presentations documented in the recent literature, and the full scope of symptoms in young children is not fully known. OBJECTIVE: The primary objectives were to gather information regarding the characteristics in the presentation of the children with positive cannabinoid urine drug screen (UDS) results in the ED and to determine if there are certain common presentations with cannabinoid ingestion or inhalation. DESIGN/METHODS: This study was a descriptive retrospective chart review from March 2013 to June 2020 of pediatric patients <18 years old with positive UDS for cannabinoids. Data collected included age, gender, chief complaint, history, review of systems, vital signs, physical exam findings, laboratory studies, imaging findings, and disposition. Four hundred and twenty-two charts were included in the study. Analysis was done using Stata 13 (College Station, TX). RESULTS: The data showed that there was a significant increase in the number of pediatric patients with a positive UDS after cannabis legalization. Using cases from November 2013 to November 2019 showed 71% of cases presented after legalization on November 8, 2016 (Z=7.72, p<.01). The majority of cases were patients between the ages of 15 and 17 (78%). 43% (n=182) of patients presented with chief complaints of suicidal ideation. The other most common chief complaints were vomiting (8%, n=33), nausea (5%, n=22), trauma (5%, n=21), and altered mental status (AMS) (5%, n=20). The most common vital sign abnormalities included tachycardia (27%, n=115) and hypertension (18%, n=74). Forty-two percent of patients had tests ordered during their visit with 7% undergoing head computerized tomography. On the UDS, 28% of patients were positive for at least one other drug with amphetamine being the most common (13%, n=55). CONCLUSION: Our data showed a significant increase in the number of cases since the legalization of cannabis in 2016, supporting the need for ED physicians to become more familiar with cannabis intoxication and its complications. The presentations of these patients can vary greatly. Common presentations include suicidal ideation, nausea/vomiting, AMS, and trauma with vital sign abnormalities including tachycardia and hypertension. Physicians should continue to consider cannabis use when evaluating these pediatric complaints. It may decrease the number of tests ordered in this patient population.

8.
Pediatr Emerg Care ; 38(2): e654-e658, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33616315

RESUMO

BACKGROUND: Computerized tomography (CT) of the abdomen and pelvis is the standard imaging modality to diagnose intra-abdominal injury (IAI). Clinicians must weigh the risk-benefit of CT compared with the degree of clinical suspicion for an IAI. Pediatric Emergency Care Applied Research Network (PECARN), Streck, and blunt abdominal trauma in children (BATiC) prediction rules have been published to help guide evaluation of these patients. Pediatric Emergency Care Applied Research Network uses history and physical examination findings, whereas Streck and BATiC use examination plus laboratory and imaging findings. At the time of the study, there was not a protocol that was more routinely sited. Our goal was to compare these different prediction rules. METHODS: This was a retrospective electronic chart review of all children younger than 18 years presenting for either level 1 or 2 trauma activations at our pediatric emergency department (ED) between June 1, 2015, to June 30, 2017. Charts were manually reviewed for a mechanism concerning for abdominal trauma, and demographic data, history and physical examination findings, laboratory and imaging results per prediction rules, and revisits in 7 days were collected.The prediction rules were applied to all charts that had all data necessary. For study purposes, a score of zero for PECARN and Streck, and score of ≤5 for modified BATiC (mBATiC) were defined as "low risk." Patients with no CT, negative CT, and no new injury found on revisit were classified as "no IAI identified," and patients with positive CT or revisit with injury found as "IAI identified." The results were compared via Fisher exact test. RESULTS: A total of 249 patients met the inclusion criteria with a median age of 12 years. Of the low-risk patients, 119 (98.7%) of 121 in PECARN group, 21 (100%) of 21 in Streck, and 48 (85.7%) of 56 in mBATiC group had no IAI identified. None of the low-risk patients required any intra-abdominal intervention. No missed IAI was identified during revisit review. Negative predictive values of all 3 rules were significant for PECARN, Streck, and mBATiC (98.35%, 100%, and 85.71%, respectively). Overall, 27 patients had positive CT results for IAI. CONCLUSIONS: The PECARN and Streck rules have high negative predictive values to predict low-risk patients who do not require CT. When laboratory studies are not obtained, PECARN is an effective means of excluding IAI for low-risk patients. When laboratory tests were obtained, the Streck rule performed well. Overall, the results are similar to the past individual studies done on each individual rule. History and physical examination findings are of high importance in pediatric trauma. This study supports limited imaging when no abnormal findings are present in children with blunt torso trauma. This is the only study found in the literature that has compared 3 different prediction rules.


Assuntos
Traumatismos Abdominais , Ferimentos não Penetrantes , Traumatismos Abdominais/diagnóstico por imagem , Criança , Técnicas de Apoio para a Decisão , Serviço Hospitalar de Emergência , Humanos , Estudos Retrospectivos , Ferimentos não Penetrantes/diagnóstico por imagem
9.
Plants (Basel) ; 12(1)2022 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-36616289

RESUMO

Huanglongbing (HLB, aka citrus greening), one of the most devastating diseases of citrus, has wreaked havoc on the global citrus industry in recent decades. The culprit behind such a gloomy scenario is the phloem-limited bacteria "Candidatus Liberibacter asiaticus" (CLas), which are transmitted via psyllid. To date, there are no effective long-termcommercialized control measures for HLB, making it increasingly difficult to prevent the disease spread. To combat HLB effectively, introduction of multipronged management strategies towards controlling CLas population within the phloem system is deemed necessary. This article presents a comprehensive review of up-to-date scientific information about HLB, including currently available management practices and unprecedented challenges associated with the disease control. Additionally, a triangular disease management approach has been introduced targeting pathogen, host, and vector. Pathogen-targeting approaches include (i) inhibition of important proteins of CLas, (ii) use of the most efficient antimicrobial or immunity-inducing compounds to suppress the growth of CLas, and (iii) use of tools to suppress or kill the CLas. Approaches for targeting the host include (i) improvement of the host immune system, (ii) effective use of transgenic variety to build the host's resistance against CLas, and (iii) induction of systemic acquired resistance. Strategies for targeting the vector include (i) chemical and biological control and (ii) eradication of HLB-affected trees. Finally, a hypothetical model for integrated disease management has been discussed to mitigate the HLB pandemic.

10.
J Agric Food Chem ; 69(37): 10807-10818, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34505777

RESUMO

A multifunctional surface, subsurface and systemic therapeutic (MS3T) formulation comprised of two bactericides, both didecyldimethylammonium chloride (DDAC) and a zinc (Zn)-chelate, was developed as an alternative to copper pesticides for crop protection. Agricultural grade chemicals were used to prepare MS3T formulations. Minimal inhibitory concentration (MIC) was determined to be tested in vitro against Xanthomonas alfalfae subsp. citrumelonis (herein called Xa), Escherichia coli (E. coli), and Pseudomonas syringae (Ps). Assessment of the phytotoxic potential was carried out on tomato under greenhouse conditions. Moreover, field trials were conducted during three consecutive years on grapefruit (Chrysopelea paradise) groves to evaluate efficacy against citrus canker (Xanthomonas citri subsp. citri), scab (Elsinoe fawcetti), and melanose (Diaporthe citri). In addition to disease control, improvements to both fruit yield and quality were observed likely due to the nutritional activity of MS3T via the sustained release of plant nutrients (Zn and nitrogen). Zn residues of leaf tissues were analyzed via atomic absorption spectroscopy (AAS) at various time points before and after MS3T foliar applications throughout the duration of the 2018 field trial. Field trial results demonstrated MS3T to be an effective alternative to copper (Cu)-based formulations for the control of citrus canker.


Assuntos
Citrus , Xanthomonas , Ascomicetos , Escherichia coli , Doenças das Plantas/prevenção & controle
11.
BMC Infect Dis ; 21(1): 862, 2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34425771

RESUMO

BACKGROUND: Serious bacterial infection rates in febrile infants < 60 days are about 8-11%. Less than 1% of febrile infants with no respiratory symptoms will have pneumonia however, chest radiography (CXR) rates remain between 30 and 60%. Rapid Respiratory Syncytial Virus (RSV) and influenza (flu) testing is common, however, there is not enough data to determine if febrile infants without any respiratory symptoms should be tested. The goal of this study is to determine the rate of positive CXR and RSV/flu results in febrile infants with no respiratory symptoms and no sick contacts. METHODS: Well-appearing febrile infants between 7 and 60 days of age who presented to the pediatric emergency department (PED) from September 1st, 2015 through October 30th, 2017 were enrolled. Demographic data, respiratory symptoms, CXR findings and RSV/flu results were collected. SAS statistical software was used for analysis. RESULTS: 129 infants met enrollment criteria. Of the 129 infants, 58 (45.0%) had no respiratory symptoms and no sick contacts. Of these 58, 36 (62.1%) received a CXR and none of them had any abnormal findings, 48 (82.8%) had RSV/flu testing, no patients tested positive for RSV and only one patient tested positive for flu. Costs of CXR and RSV/flu testing for this cohort was $19,788. CONCLUSION: The absence of positive CXRs in this patient population reinforces the current recommendations that CXR is not indicated. The low incidence of RSV/flu indicate that routine testing may not be necessary in this population especially outside of the flu season. Reduced testing could decrease overall costs to the healthcare system as well as radiation exposure to this population.


Assuntos
Influenza Humana , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Criança , Febre/epidemiologia , Humanos , Lactente , Influenza Humana/diagnóstico por imagem , Radiografia , Infecções por Vírus Respiratório Sincicial/diagnóstico por imagem , Infecções por Vírus Respiratório Sincicial/epidemiologia
12.
Nanoscale Adv ; 3(5): 1473-1483, 2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-36132859

RESUMO

The development of bacterial tolerance against pesticides poses a serious threat to the sustainability of food production. Widespread use of copper (Cu)-based products for plant disease management has led to the emergence of copper-tolerant pathogens such as Xanthomonas perforans (X. perforans) strains in Florida, which is very destructive to the tomato (Solanum lycopersicum) industry. In this study, we report a hybrid nanoparticle (NP)-based system, coined Locally Systemic Pesticide (LSP), which has been designed for improved efficacy compared to conventional Cu-based bactericides against Cu-tolerant X. perforans. The silica core-shell structure of LSP particles makes it possible to host ultra-small Cu NPs (<10 nm) and quaternary ammonium (Quat) molecules on the shell. The morphology, release of Cu and Quat, and subsequent in vitro antimicrobial properties were characterized for LSP NPs with core diameters from 50 to 600 nm. A concentration of 4 µg mL-1 (Cu): 1 µg mL-1 (Quat) was found to be sufficient to inhibit the growth of Cu-tolerant X. perforans compared to 100 µg mL-1 (metallic Cu) required with standard Kocide 3000. Wetting properties of LSP exhibited contact angles below 60°, which constitutes a significant improvement from the 90° and 85° observed with water and Kocide 3000, respectively. The design was also found to provide slow Cu release to the leaves upon water washes, and to mitigate the phytotoxicity of water-soluble Cu and Quat agents. With Cu and Quat bound to the LSP silica core-shell structure, no sign of phytotoxicity was observed even at 1000 µg mL-1 (Cu). In greenhouse and field experiments, LSP formulations significantly reduced the severity of bacterial spot disease compared to the water control. Overall, the study highlights the potential of using LSP particles as a candidate for managing tomato bacterial spot disease and beyond.

13.
Talanta ; 222: 121591, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33167269

RESUMO

In this study, a nanocomposite was synthesized via the formation of silver nanoparticles on fumed silica (FS@Ag) to prepare an electrochemical sensor for the determination of carbendazim (CBZ), a common pesticide. The electrochemical sensor was designed by the combination of the carbon paste electrode (CPE) with the FS@Ag nanocomposite. Based on the electrochemical sensor prepared here, a voltammetric method was developed for the determination of CBZ in water and food samples. Characterization of the nanocomposite was conducted by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analyses. Modified electrodes were also electrochemically characterized via cyclic voltammetry and electrochemical impedance spectroscopy analyses. The FS@Ag showed electrocatalytic activity on the electrochemical oxidation of CBZ via increasing the peak currents tremendously. With the proposed method, a very low limit of detection (9.4 × 10-10 M) and a wide linear range (5.0 × 10-8 M - 3.0 × 10-6 M) were obtained for CBZ. The slope of the calibration line obtained with CPE/15FS@Ag was 194-times higher than that of bare CPE, indicating the high sensitivity of the electrochemical sensor. The performance of the electrochemical sensor has been investigated in real samples such as river water, tomato juice, orange juice, and apple juice samples. The results reveal that the electrochemical sensor prepared here can be used as an alternative to current analytical methods used for the quantification of CBZ.

14.
Appl Environ Microbiol ; 86(16)2020 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-32561578

RESUMO

Phloem-limited bacterial "Candidatus Liberibacter" species are associated with incurable plant diseases worldwide. Antimicrobial treatments for these pathogens are challenging due to the difficulty of reaching the vascular tissue they occupy at bactericidal concentrations. Here, in vitro antimicrobial mechanisms of Zinkicide TMN110 (ZnK), a nonphytotoxic zinc oxide (ZnO)-based nanoformulation, were compared to those of bulk ZnO (b-ZnO) using as a model the only culturable species of the genus, Liberibacter crescens Minimum bactericidal concentration (MBC) determination and time-kill assays showed that ZnK has a bactericidal effect against L. crescens, whereas b-ZnO is bacteriostatic. When ZnK was used at the MBC (150 ppm), its antimicrobial mechanisms included an increase in Zn solubility, generation of intracellular reactive oxygen species, lipid peroxidation, and cell membrane disruption; all of these were of greater intensity than those of b-ZnO. Inhibition of biofilms, which are important during insect vector colonization, was stronger by ZnK than by b-ZnO at concentrations between 2.5 and 10 ppm in batch cultures; however, neither ZnK nor b-ZnO removed L. crescens preformed biofilms when applied between 100 and 400 ppm. In microfluidic chambers simulating source-to-sink phloem movement, ZnK significantly outperformed b-ZnO in Zn mobilization and bactericidal activity against L. crescens planktonic cells in sink reservoirs. In microfluidic chamber assays assessing antibiofilm activity, ZnK displayed a significantly enhanced bactericidal activity against L. crescens individual attached cells as well as preformed biofilms compared to that of b-ZnO. The superior mobility and antimicrobial activity of ZnK in microenvironments make this formulation a promising product to control plant diseases caused by "Candidatus Liberibacter" species and other plant vascular pathogens.IMPORTANCE "Candidatus Liberibacter" species are associated with incurable plant diseases that have caused billions of dollars of losses for United States and world agriculture. Chemical control of these pathogens is complicated, because their life cycle combines intracellular vascular stages in plant hosts with transmission by highly mobile insect vectors. To date, "Candidatus Liberibacter" species are mostly unculturable, except for Liberibacter crescens, a member of the genus that has been used as a model for in vitro assays. Here, we evaluated the potential of Zinkicide (ZnK) as an antimicrobial against "Candidatus Liberibacter" species in batch cultures and under flow conditions, using L. crescens as a biological model. ZnK displayed bactericidal activity against L. crescens in batch cultures and showed increased mobility and bactericidal activity in microfluidic devices resembling "Candidatus Liberibacter" species natural habitats. ZnK performance observed here against L. crescens makes this compound a promising candidate to control plant diseases caused by vascular pathogens.


Assuntos
Antibacterianos/farmacologia , Citrus/microbiologia , Nanopartículas Metálicas , Floema/microbiologia , Doenças das Plantas/prevenção & controle , Rhizobiaceae/efeitos dos fármacos , Óxido de Zinco/farmacologia , Técnicas de Cultura Celular por Lotes , Liberibacter , Microfluídica , Doenças das Plantas/microbiologia
15.
ACS Omega ; 5(3): 1402-1407, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32010811

RESUMO

Zinkicide is a systemic bactericidal formulation containing protein-size fluorescent zinc oxide-based nanoparticles (nano-ZnO). Previous studies have shown that Zinkicide is effective in controlling citrus diseases. Its field performance as an antimicrobial agent has been linked to the bioavailability of zinc ions (Zn2+) at the target site. It is therefore important to monitor Zn2+ release from Zinkicide so that application rates and frequency can be estimated. In this study, we present a simplistic approach designed to monitor Zinkicide nanoparticle dissolution rates in water and acidic buffer solutions using traditional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The evolution of nano-ZnO in the polyacrylamide gel scaffolds was studied by exciting the sample with UV light and detecting the fluorescence of nano-ZnO. Fluorescence intensities measured with this assay allowed for quantitative analysis of molecular weight changes of nano-ZnO in citrate buffer, a surrogate of citrus juice. Our results demonstrated that citrate buffer induced the greatest degradation of Zinkicide. Fluorescence intensity fluctuations were observed over time, indicating interactions of citrate with the surface of nano-ZnO. These findings provide a new approach to quantify the dissolution of nanoparticles in simulated environments, even when other analytical methods lack sensitivity because of the small size of the system (≈4 nm).

16.
Environ Monit Assess ; 192(2): 140, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31983032

RESUMO

Gypsiferous soils in karstic landscapes are important areas in terms of biodiversity and geology. One of the geological formations occurring in gypsum regions is the doline lakes. Subsidence dolines must be preserved because of their formation and fossil heritage. Erosion is one of the most serious types of degradation among these types of lakes. The Bakkal Lake is one of the most important doline lake in central Turkey and is at risks with sediment flow. In this study, we aimed to determine how erosion poses a threat to the geological heritage in areas such as doline lakes and to simulate what measures can be taken to protect them. RUSLE/GIS/remote-sensing technologies were used to estimate the distribution and amount of sediment flowing into the lake. According to the results of the study, the amount of sediment transported to the lake was estimated to be 2.73tha-1y-1, and the total amount of sediment transported was 2876 m3y-1. The time until Bakkal Lake is filled with sediment flux was calculated to be 698 years. The simulation was developed by offering protection measures to reduce sediment flow to the lake. As a result of the simulation, it was calculated that the amount of sediment flowing into the lake decreased to 2.29 tha-1y-1 and the filling time increased to 833 years. The study showed that a doline lake, which under natural processes would not be filled for thousands of years, will soon be filled unless radical measures are not taken. This study asserts that more planners should use simulations to model sediment flow to better select appropriate conservation measures.


Assuntos
Monitoramento Ambiental , Lagos , Solo , Sedimentos Geológicos , Turquia
17.
Bioprocess Biosyst Eng ; 43(2): 217-232, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31559507

RESUMO

The goals of this study were to optimize the medium formulation for enhanced production of Aspergillus niger inulinase using Plackett-Burman Design (PBD) and to model the fermentation in optimal medium formulation. Results indicated that (NH4)2SO4 (negative effect), yeast extract and peptone (positive effect) were determined as significant factors affecting the inulinase production. Different media including Medium A (non-enriched), Medium B (contains both negative and positive factors) and Medium C (contains only positive factors) were formed and inulinase fermentations were performed. Findings showed that the best nutritional formulation was Medium C, which yielded to be 1011.02 U/mL, 834.28 U/mL, 1.22, 4383.44 U/mg, 4186 U/mg, 158.49 U/mL/day, 128.60 U/mL/day and 94.54% of PInulinase, SInulinase, I/S ratio, SInulinase, SSucrase, QInulinase, QSucrase and SUY, respectively. Additionally, fungal growth, enzyme or protein production and substrate consumption were modeled using the logistic model, Luedeking-Piret model, and modified Luedeking-Piret model, respectively, and found that enzyme or protein production was non-growth associated. Besides, maintenance value (Z) was lower than γ value, indicating that A. niger mainly utilizes the sugars for enzyme production and fungal growth. Consequently, optimum medium composition was successfully determined by PBD and also the kinetic models fitted the experimental data very well with high regression coefficient.


Assuntos
Aspergillus niger/enzimologia , Proteínas Fúngicas/biossíntese , Glicosídeo Hidrolases/biossíntese , Modelos Biológicos , Cinética
18.
J Agric Food Chem ; 67(45): 12393-12401, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31596571

RESUMO

Accumulation of toxic copper in soil and development of copper-resistant pests are emerging challenges currently faced by the agricultural community worldwide. As an alternative, we have developed a ternary zinc chelate solution (TSOL) pesticide where zinc ions are the primary active ingredient. The material is composed of zinc, urea, and hydrogen peroxide. Urea was chosen as it is widely used as a plant fertilizer and can also bind to both zinc and hydrogen peroxide. No phytotoxicity was observed with TSOL on Meyer lemon (Citrus × meyeri) seedlings at a field spray rate of 800 µg/mL Zn metal concentration. Antimicrobial studies showed that TSOL exhibited improved killing efficacy against Escherichia coli and Xanthomonas alfalfae compared to Zn ions alone. Citrus canker field trials in a grapefruit (Chrysopelea paradisi) grove over three years showed that TSOL provided comparable disease protection to copper products at an equivalent or lower metal content.


Assuntos
Antibacterianos/química , Citrus/microbiologia , Peróxido de Hidrogênio/química , Doenças das Plantas/microbiologia , Ureia/química , Zinco/química , Zinco/farmacologia , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Peróxido de Hidrogênio/farmacologia , Folhas de Planta/microbiologia , Ureia/farmacologia , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
19.
Pathogens ; 8(3)2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31374947

RESUMO

Nosocomial infections pose serious health concerns with over 2 million reported annually in the United States. Many of these infections are associated with bacterial resistance to antibiotics and hence, alternative treatments are critically needed. The objective of this study was to assess the antimicrobial efficacy of a gallium (Ga)-based particle coated with N-Acetyl Cysteine (Ga-NAC) against Pseudomonas aeruginosa PAO1. Our studies showed the Minimum Inhibitory Concentration (MIC) of PAO1 treated with Ga-NAC was 1 µg/mL. Cytotoxicity of Ga-NAC against multiple cell lines was determined with no cytotoxicity observed up to concentrations of 2000 µg/mL (metal concentration), indicating a high therapeutic window. To elucidate potential antibacterial modes of action, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), infrared spectroscopy, and atomic force microscopy (AFM) were used. The results suggest improved Ga3+ interaction with PAO1 through Ga-NAC particles. No significant change in cell membrane chemistry or roughening was detected. As cell membrane integrity remained intact, the antimicrobial mode of action was linked to cellular internalization of Ga and subsequent iron metabolic disruption. Furthermore, Ga-NAC inhibited and disrupted biofilms seen with crystal violet assay and microscopy. Our findings suggest the Ga-NAC particle can potentially be used as an alternative to antibiotics for treatment of Pseudomonas aeruginosa infections.

20.
PLoS One ; 14(6): e0218900, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31233560

RESUMO

Ternary solution (TSOL) is a novel Zn chelate-based systemic antimicrobial formulation designed for treating citrus bacterial pathogens 'Candidatus Liberibacter asiaticus' and Xanthomonas citri subsp. citri. TSOL is a component of MS3T, a novel multifunctional surface/sub-surface/systemic therapeutic formulation. Antimicrobial activity of TSOL was compared with the antimicrobial compound ZnO against X. citri subsp. citri and 'Ca. L. asiaticus' surrogate Liberibacter crescens in batch cultures. X. citri subsp. citri and L. crescens were also introduced into microfluidic chambers, and the inhibitory action of TSOL against biofilm formation was evaluated. The minimum inhibitory concentration of TSOL for both X. citri subsp. citri and L. crescens was 40ppm. TSOL was bactericidal to X. citri subsp. citri and L. crescens above 150 ppm and 200 ppm, respectively. On the contrary, ZnO was more effective as a bactericidal agent against L. crescens than X. citri subsp. citri. TSOL was more effective in controlling growth and biofilm formation of X. citri subsp. citri in batch cultures compared to ZnO. Time-lapse video imaging microscopy showed that biofilm formation of X. citri subsp. citri was inhibited in microfluidic chambers treated with 60 ppm TSOL. TSOL also inhibited further growth of already formed X. citri subsp. citri and L. crescens biofilms in microfluidic chambers. Leaf spraying of TSOL showed higher plant uptake and systemic movement in citrus (Citrus reshni) plants compared to that of ZnO, suggesting that TSOL is a promising antimicrobial compound to control vascular plant pathogens such as 'Ca. L. asiaticus'.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Citrus/microbiologia , Rhizobiaceae/efeitos dos fármacos , Xanthomonas/efeitos dos fármacos , Zinco/metabolismo , Liberibacter , Testes de Sensibilidade Microbiana/métodos , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...