Highest Percentage Of Inhibition Research Articles

Isolation of Potential Antagonistic Rhizosphere Fungi against Alternaria alternata from Organic Carrot Productions

Rhizospheric fungi can have serve as biological agents against plant pathogens Alternaria alternata, which infects carrot plants. Rhizospheric fungi are more abundant in organic lands. This study aims to isolate fungi from organic carrot’s rhizosphere that are able to suppress A. alternata’s growth and determine isolate rhizospheric fungi ability to inhibit A. alternata to identify potential biological control agents against A. alternata. This research was conducted at the Laboratory of Biotechnology and Basic Biology, Diponegoro University, between January–June 2023. Research methods include survey location, soil sampling, rhizospheric fungi isolation, pathogenic fungi isolation, creating growth curve, pathogenicity tests, antagonism tests, and fungi identification. This study used a complete randomized design (CRD) and was analyzed using ANOVA at the 5% level of significance and Duncan's hoc-posttest. Fungi isolation from organic carrot plant’s rhizosphere resulted in 13 isolates consisting of six genera: Penicillium, Aspergillus, Paecilomyces, Myrothecium, Trichoderma, and Simplicillium. The antagonism test showed that eight antagonistic isolates, including the genus Penicillium (WO1, WO6, WO10), Paecilomyces (WO5), Myrothecium (WO7), Trichoderma (WO9), and Aspergillus (WO11, WO13), where WO1, WO6, WO10, and WO11 have a medium percentage of inhibition (44.12-57.84%), while WO5, WO7, WO9, and WO13 have a high percentage of inhibition (64.29-76.06%). The eight isolates showed antagonism mechanisms, including antibiosis (WO1, WO5, WO6, WO7, WO10, and WO11) and parasitism (WO9 and WO13).

Potential mechanism of gallic acid-coated iron oxide nanoparticles against associated genes of Klebsiella pneumoniae capsule, antibacterial and antibiofilm.

Antibiotic resistance has increased in recent years, especially for pathogens like Klebsiella pneumoniae. Discovering and developing new drugs is challenging due to the high resistance of pathogens. Metal nanoparticles have been widely used in recent years to overcome and treat infections. Gallic acid-coated iron oxide nanoparticles (IONPs-GA) were synthesized in a simple and cost-effective method. The morphology characteristics of synthesized IONPs-GA were analyzed using Fourier transform infrared spectroscopy (FTIR), x-ray diffraction analysis (XRD), and scanning electron microscope (SEM) analysis. IONPs were mostly spherical in shape with sizes ranging between 32 and 61 nm. All analyses used in this study confirmed the successful coating of gallic acid to iron oxide. Biological activities were studied phenotypically and on the molecular level, including antibacterial, antibiofilm, and mRNA levels of capsule-associated genes. The results showed high antimicrobial activity of the synthesized nanoparticles against different G+ve and G-ve bacteria. The highest activity was recorded against Staphylococcus aureus (43 mm) and K. pneumoniae (22 mm). The MIC of IONPs against K. pneumoniae was 3.12 mg/mL and SEM analysis showed adhering the IONPs-GA to the cell surface of K. pneumoniae resulted in disrupting the cell membrane. Different concentrations of sub-MIC inhibited K. pneumoniae biofilm formation with the highest inhibition percentage at ½ × MIC (66.86%). Also, the synthesized IONPs-GA differently affected the regulation and mRNA level of capsule-associated genes in K. pneumoniae. The results indicated that IONPs-GA could be useful in biological applications such as in drug delivery and treatment wide range of pathogens. RESEARCH HIGHLIGHTS: Gallic acid was successfully coated into iron oxide nanoparticles synthesized in a simple way. IONPs-GA was morphologically characterized using FTIR, XRD, and SEM. Evaluation the activity of IONPs-GA as antibacterial, antibiofilm, and study the potential level of mRNA affected by IONPs-GA.

GC-MS Analysis, Antioxidant, Antidiabetic Activity, and ADMET Study of Diospyros mespiliformis Hochst. Ex A. DC. Ebenaceae Stembark

The present study carried out GC-MS analysis, antioxidant, antidiabetic, and ADMET study of the crude ethanol extract (CRE), ethyl acetate (EAF), and aqueous (AQF) fractions of Diospyros mespiliformis (DM). Grandiflorenic (25.36%) and cis, cis-linoleic (27.13%) acids were the most abundant of the 59 and 40 compounds identified in the EAF and AQF, respectively. The EAF and CRE exhibited total antioxidant capacity of 77.78 ±0.01 ascorbic acid equivalent (mg AAE/g extract) and 60.20 ±0.01 mg AAE/g extract, respectively, significantly (p < 0.05) than the AQF (29.63 ±0.01 mg AAE/g extract). Furthermore, the EAF (38.27% ±2.44) exhibited a significantly (p < 0.05) higher percentage inhibition via the ferric thiocyanate assay than the CRE (17.45% ±2.18) and AQF (15.91% ±2.11). All the extracts showed significantly (p < 0.05) lower malondialdehyde concentrations than AA in the thiobarbituric acid assay. Additionally, the AQF exhibited a significantly higher percentage of H2O2 scavenging than the AA and EAF at 100 µg/ml. Diazoprogesterone (compound III) identified in the EAF exhibited the lowest respective binding affinity and inhibition constant, interacting with myeloperoxidase (-9 kcal/mol and 0.25 µM), xanthine oxidase (-9.9 kcal/mol and 0.05 µM), 11-β-hydroxysteroid dehydrogenase (-10 kcal/mol and 0.05µM), and sirtuin 6 (-10 kcal/mol and 0.05 µM). The molecular dynamics simulations showed residue fluctuations of the diazoprogesterone-docked complexes with the highest observed at Ser42 (5.14 Å), Cys1325 (8.96 Å), Ser281 (7.71 Å), and Leu78 (3.91 Å) for myeloperoxidase, xanthine oxidase, 11-β-hydroxysteroid dehydrogenase, and sirtuin 6, respectively compared to the undocked targets. Moreover, diazoprogesterone was predicted to possess good ADMET properties. Conclusively, DM possesses significant antioxidant and antidiabetic potential, containing compounds that might be a source of novel therapeutics against oxidative stress and diabetes.

Evaluation of butterfly pea powder addition to cow’s milk kefir on the antibacterial activity against bacteria causing foodborne disease

Abstract Foodborne diseases are caused by consuming food contaminated with pathogens such as bacteria, viruses, parasites, or toxic chemicals, as well as biotoxins. Bacteria responsible for foodborne disease include Escherichia coli and Staphylococcus aureus. The typical approach to managing foodborne disease involves the use of antibiotics, which might lead to resistance over time. Kefir is a probiotic drink that can help maintain health by balancing the natural gut microflora. This study aims to investigate the impact of adding butterfly pea powder to kefir on its antibacterial activity against the bacteria that cause foodborne disease. Kefir was prepared by adding butterfly pea powder in six different concentrations (0%, 0.5%, 1%, 1.5%, 2%, and 2.5%) with four replications. Kefir’s pH, total titrated acid, total LAB, and its antibacterial activity using the microdilution method were observed. The results revealed that the addition of butterfly pea flower powder at various concentrations significantly influenced the pH value, total acidity, and antibacterial effects against E.coli and S.aureus but did not significantly affect the total LAB count. Butterfly pea flower powder reduced the pH value, increased the total acidity, and enhanced the antibacterial activity, resulting in a higher percentage of inhibition against the tested bacteria without adversely affecting LAB growth. It was concluded that adding butterfly pea powder to cow milk kefir potentially improves the antibacterial functions against bacteria causing foodborne disease.

Efeito da adubação orgânica na produção de ácidos graxos e atividade antidiabética de Portulaca oleracea L.

Portulaca oleracea L., commonly known as purslane, is a plant consumed in Europe, Asia and Africa, with nutraceutical compounds and essential fatty acids whose content exceeds that of vegetables such as spinach and lettuce. On the other hand, organic fertilization improves the physical-chemical characteristics of the soil and thus promotes growth, physiology and secondary metabolism, improving the chemical composition of the plant. In order to evaluate the effect of organic fertilization on fatty acid content and anti-diabetic activity (α-Glucosidase), greenhouse-grown plants were subjected to three treatments: control without additional fertilizers, with compost and vermicompost. The results indicated that vermicompost significantly increased oleic and linoleic acid content. However, palmitic acid content decreased, although other saturated fatty acids such as lauric, myristic and stearic acids did not show variations in the different treatments. Of the polyunsaturated essential fatty acids, linolenic acid (omega-3) increased in the control treatment. On the other hand, the enzyme α-Glucosidase did not show differences in the different fertilization treatments. However, its high percentage of inhibition (60 %) positions it as a species with high antidiabetic potential.

Identification of Endophytic Actinomycetes Isolated From Hopea ferrea and Its Antibacterial Activity Against Cariogenic Bacterium

Dental caries affects around 36% of the world's population and results in the loss of primary teeth in about 530 million youngsters. It is described as the loss of the enamel layer of the tooth by acids generated by the activity of cariogenic bacterium such as Streptococcus mutans on carbohydrates. This study aims to identify bioactive endophytic actinomycetes as an antibacterial agent against S. mutans DSM 20523 and to identify the bioactive endophytic actinomycetes using the 16S rRNA sequencing approach. To determine the percentage zone of inhibition, three endophytes at 10-day-old culture have been streaked onto ISP2. Then, S. mutans was streaked perpendicular to the endophytes. Crude extracts from three endophytes have been prepared by using four different types of media namely Tryptic Soy broth, Kings B, International Streptomyces Project Medium No.1 (ISP1) and Starch Casein broth. These crude extracts proceeded to undergo disk diffusion and MIC assays against S. mutans. All three endophytes from streaked plates with the highest percentage zone of inhibition were identified using the 16S rRNA gene molecular approach for characterisation. Endophytic actinomycetes which were isolated from Hopea ferrea showed potent antibacterial activity against S. mutans. All endophytic actinomycetes isolates from streak plates showed good inhibitory activity against the S. mutans. The highest percentage of inhibition was shown by the PT9-13S2 isolate followed by PT9-8S2 and PT9-13W2. Furthermore, crude extracts of PT9-8S2 and PT9-13W2 (the highest ZOI) from TSB media showed inhibitory activities against S. mutans, from disk diffusion as well as minimum inhibitory assays. From the 16S rRNA molecular approach, endophytic actinomycetes PT9-8S2 was closely related to Streptomyces collinus while PT9-13S2 and PT9-13W2 were closely related to Streptomyces malachitospinus. From this study, endophytic actinomycetes showed a promising source as antibacterial agents against cariogenic bacterium S. mutans which is the main causative agent of dental caries.

Phytochemical Evaluation and Anti-angiogenic Activity of Alingatong (Dendrocnide meyeniana Walp.) Root Extracts Using the Chorioallantoic Membrane Assay on Duck Embryo

Dendrocnide meyeniana (Walp.), known as "Alingatong" in the Visayas region of the Philippines, is a plant from the Urticaceae family. It is commonly found in the mountain areas of Taiwan and the Philippines. This study aims to determine the Dendrocnide meyeniana root extract's anti-angiogenic activity. The methanolic extracts of Dendrocnide meyeniana were subjected to preliminary phytochemical screening. Cytotoxicity test using Brine Shrimp Lethality Assay was conducted with different plant concentrations to determine the concentration to use for the anti-angiogenic activity of the root extracts. The anti-angiogenic activity was observed by calculating blood vessel percent inhibition using chorioallantoic membrane assay or CAM assay. Phytochemical screening reveals that the plant contains varying levels of detection of bioactive compounds, including saponins, flavonoids, alkaloids, and steroids. Brine Shrimp Lethality Assay showed that the ethyl acetate and hexane extracts from Dendrocnide meyeniana were highly toxic as their LC50 values were lower than 100 ppm. CAM assay results showed that hexane with 250 ppm concentration has the highest percent inhibition with 34.98% followed by hexane at 125 ppm with 34.07% inhibition. Both concentrations of ethyl acetate showed low percentage inhibition, where 250 ppm was at 19.05% and 125 ppm at 15.93%. One-way ANOVA indicates that the different treatments have significant differences (p-value< 0.0001) in the number of branches present using the CAM assay. Therefore, based on the results, Dendrocnide meyeniana root extracts have anti-angiogenic properties and these findings will help to understand the efficacy of the traditional medicine used by the local people.

Synthesis of New Chroman-4-one Based 1,2,3-Triazole Analogues as Antioxidant and Anti-Inflammatory Agents.

A library of new chroman-4-one based 1,2,3-triazole analogues were synthesized involving a series of condensation, cyclization, Suzuki coupling and copper catalysed click chemistry protocols. The newly synthesized compounds 8a-l were screened for their invitro antioxidant and anti-inflammatory activities by employing Ascorbic acid and Diclofenac as reference drugs respectively. The compound without any substituent on benzyl ring (8a), compound with -Cl substituent in para position of benzyl ring (8i), and compound with ethoxy substituent in para position of benzyl ring (8k) exhibited potent antioxidant and anti-inflammatory activities with higher percentage of inhibition. To understand their binding affinities, molecular docking study of these three compounds performed against NADPH oxidase with presented outstanding docking scores and promising binding interactions like H-bond and hydrophobic.

Isolation and identification fungi contaminated onion bulbs, detection Aspergillus spp. toxins, and inhibiting its growth by Moringa oleifera extract

The study aimed to isolate and diagnose fungi contaminating onion fruits and secreting mycotoxins, and to study the effect of Moringa oleifera extract on the growth of the fungus Aspergillus niger. The results of isolating fungi from onions showed the presence of the following fungi: Aspergillus niger, Fusarium sp., and Rhizopus stolonifer. It became clear that there was a predominance of the fungus A. niger, then the fungus Fusarium sp., followed by the fungus Rhizopus stolonifur, as their frequency rates reached 53.33, 36.66, and 10.00%, respectively, while the occurrence rate reached 83.33, 50.00, and 33.33%, respectively. In this study, molecular diagnosis of the fungus A. niger was carried out using internal transcribed spacer (ITS) genetic markers, and the results of chemical analysis using thin layer chromatography (TLC) showed that 9 of the 16 isolates were A. niger, isolated from onions, produced ochratoxin A with a production rate of 56.25%. The moringa extract inhibited the growth of the fungus A. niger, as the percentage of inhibition increased with increasing concentration, and the highest percentage of inhibition was at a concentration of 15%, which reached 47.32%. The percentage of inhibition was at concentrations of 5 and 10 (12.82 and 26.15%).

Design, synthesis and biological evaluation of novel pyrazole-based compounds as potential chemotherapeutic agents.

Aim: Design and synthesis of pyrazole-based chemotherapeutic agents. Materials & methods: A series of novel diphenyl pyrazole-chalcone derivatives were synthesized and assessed for their cytotoxic activities against 14 cancer cell lines and their antimicrobial activities against MRSA and Escherichia coli along with their safety using HSF normal cell line. Results & conclusion: Majority of the compounds showed moderate-to-significant anticancer activity with selective high percentage inhibition (>80%) against HNO-97 while being nontoxic toward normal cells. Compounds 6b and 6d were the most potent congeners with IC50 of 10 and 10.56μM respectively. The synthesized compounds exhibited moderate to potent antimicrobial activities. Interestingly, compound 6d exhibited a minimum inhibitory concentrationof 15.7μg/ml against MRSA; and a minimum inhibitory concentrationof 7.8μg/ml versus E. coli.

Antimicrobial, antibiofilm, and antiviral investigations using egyptian phoenix dactylifera L. pits extract

Phoenix dactylifera L. and its wastes are known to be high in nutrients that are beneficial to human health. The study aimed to evaluate the antimicrobial, antibiofilm, and antiviral properties of Phoenix dactylifera L. pits extract (PDPE) in vitro. Gas chromatography-mass spectrometry (GC–MS) analysis indicated phenol, 2,5-bis(1,1-dimethyl ethyl), tetradecanoic acid, octaethylene glycol monododecyl ether, á-D-glucopyranosiduronic acid, and heptaethylene glycol monododecyl ether existence. The PDPE influenced pathogenic microorganisms, with inhibition zone diameters (IZDs) ranging from 10.0 to 35.0 mm. Staphylococcus aureus ATCC 5638 had the highest IZD, while Salmonella typhi DSM 17058 and Shigella sonnei DSM 5570 had the lowest. The antifungal effect observed only in spore failure or conidia formation. PDPE showed a 100% antibacterial spectrum against bacteria, with MIC values between 250 and 1000 µg/ml. MIC was only indicated with S. aureus of 500 µg/ml. MBC values ranged from 500 to 1000 g/ml, with MBC values of 500 g/ml for B. cereus, E. faecalis, S. typhi, and S. sonnei. The activity was 66.7% at 500 µg/ml, further concentrations of 125–250 g/ml had no antibacterial effect. PDPE biofilm inhibition % had the highest percentage of inhibition (98.59%) with S. aureus, B. cereus (94.12%), and E. coli (74.46%). With 50% (CC50) viral activity, the highest non-toxic PDPE dose was found to be at 123.0 µg/ml.

Anthelmintic activity and chemical profile of native plant extracts from the Yucatan Peninsula against Toxocara canis

Toxocara canis can produce the “larva migrans” syndrome in humans, and in puppies, it can cause severe digestive disorders. The most used treatments are based on anthelmintics, although there are reports of anthelmintic (AH) resistance. The Yucatan Peninsula has a great variety of plant species whose AH properties are still unknown. The objective of this study was to evaluate the in vitro AH activity of ethanolic (EE), methanolic (ME) and aqueous (AE) extracts from the leaves of five native plant species of the Yucatan Peninsula on T. canis eggs of dogs from Merida, Yucatan. As part of a screening, the EE of the plants Alseis yucatanensis, Calea jamaicensis, Cameraria latifolia, Macrocepis diademata, and Parathesis cubana were evaluated at doses of 2400 and 3600 μg/ml. The EE and AE of A. yucatanensis and M. diademata presented high percentages (≥ 91.3%) of inhibition of the larval development of T. canis after six days of exposure. The lowest LC50 and LC99 was presented by the ME from A. yucatanensis (255.5 and 629.06 µg/ml, respectively) and the ME from M. diademata (222.4 and 636.5 µg/ml, respectively), and the AE from A. yucatanenesis (LC50 of 535.9 µg/ml). Chemical profiling of the most potent AH extract (Alseis yucatanensis) was carried out by LC-UV-HRMS. Data from the ME and AE from this plant indicated the presence of the known glucosylngoumiensine, kaempferol 3,7-diglucosyde, uvaol, linoleic acid and linolenic acid together with unknown alkaloids. The EE, ME and AE from leaves of M. diademata and A. yucatanensis could be developed as natural alternatives to control T. canis.

Antagonistic Effect of Endophytic Fungi Isolated from Nerium olender against Rhizoctonia solani

Objective: To investigate the population of endophytic fungi accompanying to Nerium olender plant. Materials and Methods: The study was conducted on three different sites in two governorates for three consecutive months with five samples from each site. The identification of the fungi was carried out using microscopic and molecular methods while the isolation, identification of fungal pathogen and preparation of aqueous extract were also successfully done. Results: 14 species of fungi (Penicillium notatum, Rhizopus nigricans, Rhizopus stolonifera, Fusarium Solani, Fusarium oxysporum, Alternaria sp., Cladosporium sp .and Curvularia sp.), while the other sex species were identified by DNA investigation method and where (Aspergillus spp. (40%), Penicillium spp. (20%), Rhizopus spp. (12%), Fusarium spp. (10%), Alternaria sp. (4%), Mucor circinelloides (4%), Neurospora Crassa (3%), Cladosporium sp. (1%) and Curvularia sp. (1%). Conclusions: The highest percentage of inhibition was for fungi Aspergillus Flavus, Penicillium commune and Mucor circinelloides which amounted to 100% and from the third day of growth until the completion of the control dish, then Aspergillus niger and Rhizopus stolonifera, with a 90% on the seventh day of growth, and Penicillium commune, Rhizopus nigricans with a rate ranging between 82-68%, while the rest of the fungi showed an antagonistic effect, but with rates less than 50%.

Evaluation of the antiplasmodial activity of <i>Curcuma longa</i> (turmeric - Zingiberaceae) on <i>Plasmodium berghei</i> in laboratory mice.

Malaria is a leading cause of morbidity and mortality worldwide, especially in developing countries and in sub-Saharan Africa where most malaria cases and deaths occur. The resistance of malaria parasites to most anti-malaria drugs, coupled with the high cost and the toxic effects of some drugs has posed a challenge for the search of new effective anti-malarial compounds of low cost. The study aims to determine the antiplasmodial activity of Curcuma longa against Plasmodium berghei in rodents. A total of 110 Swiss albino mice weighing 18-30 grams were used for the study: 35 for the toxicity test and 75 for the antimalarial study. For each test, 25 mice were inoculated with drug-sensitive Nk65 Plasmodium berghei and divided into five groups of five animals each and each group was administered one of the following: 120mg/kg of ethanol extract, 120mg/kg water extract, 120mg/kg nHexane extracts of C. longa, 1.2mg/kg of pyrimethamine or 5mg/kg of Chloroquine (positive control) and 0.2mls of normal saline (negative control). The lethal dose concentration was above 1500mg/kg and the extracts showed significant (P<0.05) antimalarial activity with the highest percentage inhibition (67.49%) recorded in the group treated with ethanol in the curative test, followed by the group given water in the suppressive test with (65.03%) and nHexane in the prophylactic test with percentage inhibition of 64.98%. There was a slight difference in the antimalarial activities of the extracts of different solvents which all had lower activities compared with the standard drugs (Chloroquine administered at 5mg/kg or pyrimethamine, 1.2mg/kg/day) but no total clearance of the parasite was recorded. C. longa possesses considerable antiplasmodial activity, which can be exploited in malaria therapy.

Copaifera mildbraedii Desf.: Phytochemical Composition of Extracts, Essential Oil, and In Vitro Biological Activities of Bark

Copaifera mildbraedii Desf. is an evergreen tree with an umbrella-like crown. It is distributed from south-eastern Nigeria eastward to the Central African Republic (CAR). The aim of this study was to assess the chemical composition and biological activities of C. mildbraedii bark, as well as the chemical composition of the essential oil. Ethyl acetate (EtOAc) and methanol (MeOH) extracts showed a high total phenolic content (TPC) (149.9 and 148.8 mg GAE/g dry residue (dr), respectively), which was related to good antioxidant activity (DPPH) with an IC50 of 21.2 and 12.9 µg/mL, respectively. High-performance liquid chromatography coupled with diode array detector (HPLC-DAD) analysis revealed seven phenolic compounds with myricitrin (13.3 mg/g dr) and 2,4-dihydroxy-3,6-dimethyl benzoic acid (30.7 mg/g dr) as major compounds, while gas chromatography-mass spectrometry (GC-MS) analysis enabled detection of 13 volatile compounds (3 before and 10 after derivatization). Thirty compounds were identified in the essential oil, which corresponds to 65% of all identified compounds. Among the latter, E,E-farnesylacetone and γ-gurjunene were considered as major compounds (8.08 and 10.43%, respectively). The EtOAc extract showed a potent potential, simultaneously, against anti-acetylcholinesterase (AChE), anti-15-lipoxygenase (15-LOX), anti-xanthine oxidase (XOD), and cytotoxic (OVCAR) activities, whereas cyclohexane (CYHA) and dichloromethane (DCM) extracts showed a cytotoxic effect with high percentages of inhibition (95.2%).

Formulation and Evaluation of Herbal Emulsion-Based Gel Containing Combined Essential Oils from Melaleuca alternifolia and Citrus hystrix

Aims: This study aimed to investigate the synergistic anti-inflammatory effects of combined essential oils from Melaleuca alternifolia and Citrus hystrix peel. Methodology: An emulsion-based gel containing combined essential oils from Melaleuca alternifolia and Citrus hystrix peel was topically applied to the injected area of the carrageenan-induced hind paw edema mouse model. Diclofenac sodium was used as a positive control. The inhibition percentage of protein denaturation in all mice was assessed and calculated based on paw volume (Pv). Results: The highest inhibition percentage, recorded at the third hour in the carrageenan-induced hind paw edema mouse model, was 44.76%, achieved by the mice treated with combined essential oils. This was followed by diclofenac-treated (37.14%), tea tree essential oil-treated (27.62%), and kaffir lime peel essential oil-treated mice (20.10%). A similar trend was observed after 24 hours of treatment, with the anti-inflammatory activity of combined essential oils-treated mice recorded at 46.74%, followed by diclofenac-treated (35.87%), tea tree essential oil-treated (24.97%) and kaffir lime peel essential oil-treated mice (11.97%). Conclusion: These findings confirm the synergistic anti-inflammatory effects of the combined essential oils-incorporated emulsion-based gel on the carrageenan-induced hind paw edema mouse model.

In vitro evaluation of the inhibitory capacity of three Trichoderma isolates on Ralstonia solanacearum

Bacterial wilt in bananas, caused by Ralstonia solanacearum or Moko, limits crop production and threatens Ecuador. This study evaluated Trichoderma isolates in laboratory conditions as an innovative alternative to ensure sustainability in banana production. The four R. solanacearum. isolates were obtained from banana plants exhibiting disease symptoms and were characterized through morphological and biochemical tests. Four treatments were evaluated: three isolates of fungi from the genus Trichoderma (Trichoderma viride, T. harzianum, T. asperellum) and one consisting of a combination of the three isolates above. The inhibitory capacity of the Trichoderma isolates on R. solanacearum colonies was measured. A completely randomized design with three replicates was used, and general linear and mixed models were employed, with qq-plot graphs for normality and residual plots for variance homogeneity. Furthermore, a Fisher's LSD test was conducted at a significance level of α = 0.05. In the biochemical tests, the bacterial isolates exhibited specific characteristics of R. solanacearum in two bacterial isolates. In the inhibition tests, treatment four and treatment one (consortium of the three Trichoderma isolates and Trichoderma viride) showed the highest inhibitory potential, with 76.07% and 61.19%, respectively. The consortium of Trichoderma isolates demonstrated the highest inhibitory potential against R. solanacearum, with day 10 being the time with the highest percentage of inhibition (72.61%). Keywords: Bacterial wilt, Ralstonia solanacearum, Trichoderma, inhibition

In vitro evaluation of the inhibitory capacity of three Trichoderma isolates on Ralstonia solanacearum

Bacterial wilt in bananas, caused by Ralstonia solanacearum or Moko, limits crop production and threatens Ecuador. This study evaluated Trichoderma isolates in laboratory conditions as an innovative alternative to ensure sustainability in banana production. The four R. solanacearum. isolates were obtained from banana plants exhibiting disease symptoms and were characterized through morphological and biochemical tests. Four treatments were evaluated: three isolates of fungi from the genus Trichoderma (Trichoderma viride, T. harzianum, T. asperellum) and one consisting of a combination of the three isolates above. The inhibitory capacity of the Trichoderma isolates on R. solanacearum colonies was measured. A completely randomized design with three replicates was used, and general linear and mixed models were employed, with qq-plot graphs for normality and residual plots for variance homogeneity. Furthermore, a Fisher's LSD test was conducted at a significance level of α = 0.05. In the biochemical tests, the bacterial isolates exhibited specific characteristics of R. solanacearum in two bacterial isolates. In the inhibition tests, treatment four and treatment one (consortium of the three Trichoderma isolates and Trichoderma viride) showed the highest inhibitory potential, with 76.07% and 61.19%, respectively. The consortium of Trichoderma isolates demonstrated the highest inhibitory potential against R. solanacearum, with day 10 being the time with the highest percentage of inhibition (72.61%). Keywords: Bacterial wilt, Ralstonia solanacearum, Trichoderma, inhibition

Antifungal Activity of Phyllospheric Bacteria Isolated from Coffea arabica against Hemileia vastatrix.

Peru is one of the leading countries that produce and export specialty coffees, favorably positioned in the international markets for its physical and organoleptic cup qualities. In recent years, yellow coffee rust caused by the phytopathogenic fungus Hemileia vastatrix stands out as one of the main phytosanitary diseases that affect coffee culture yields. Many studies have demonstrated bacteria antagonistic activity against a number of phytopathogen fungi. In this context, the aim of this work was to select and characterize phyllospheric bacteria isolated from Coffea arabica with antagonistic features against coffee rust to obtain biocontrollers. For that purpose, a total of 82 phyllospheric bacteria were isolated from two coffee leaf rust-susceptible varieties, typica and caturra roja, and one tolerant variety, catimor. Of all the isolates, 15% were endophytic and 85% were epiphytes. Among all the isolates, 14 were capable of inhibiting the mycelial radial growth of Mycena citricolor, and Colletotrichum sp. 16S rRNA gene sequence-based analysis showed that 9 isolates were related to Achromobacter insuavis, 2 were related to Luteibacter anthropi and 1 was related to Rodococcus ceridiohylli, Achromobacter marplatensis and Pseudomonas parafulva. A total of 7 representative bacteria of each group were selected based on their antagonistic activity and tested in germination inhibition assays of coffee rust uredinospores. The CRRFLT7 and TRFLT8 isolates showed a high inhibition percentage of urediniospores germination (81% and 82%, respectively), similar to that obtained with the chemical control (91%). An experimental field assay showed a good performance of both strains against rust damage too, making them a promising alternative for coffee leaf rust biocontrol.

Influence of Galvanized Steel on Kombucha Fermentation: Weight Loss Measurements, Scanning Electron Microscopy Analysis, Corrosion Activity, and Phytochemical Study

This study aimed to investigate the influence of galvanized steel coupons on black tea kombucha fermentation. As a secondary objective, the corrosion activity of the fermented medium at different stages of fermentation was investigated. The results revealed significant interactions among microorganisms, the metal, and the fermented medium. On one hand, mass loss measurement, scanning electron microscopy (SEM) analysis, and released zinc and iron ion analysis showed the deterioration of galvanized steel coupons. On the other hand, HPLC-RI analysis showed that the presence of steel coupons improved the kinetics of fermentation. The chemical composition and bioactivity of kombucha were also influenced by the presence of galvanized steel. The results showed the detection of eleven phenolic compounds by HPLC-DAD, including trihydroxyethylrutin, methyl 3,5-dihydroxybenzoate, and ethyl 4-hydroxy-3-cinamate, which were found only in kombucha in the presence of galvanized steel (K+GS). In addition, a total of 53 volatile compounds were detected by GC-MS before and after derivatization, including eleven constituents identified for the first time in K+GS. Concerning antioxidant activity, a higher percentage of inhibition against the DPPH radical was attributed to the ethyl acetate extract found in K+GS (IC50 = 8.6 µg/mL), which could suggest the formation of inhibitors. However, according to the electrochemical findings, the corrosion current density increased threefold during the fermentation process compared to acidified black tea, indicating that corrosion activity was promoted in the kombucha medium and suggesting several competing phenomena between corrosion and inhibition.