scholarly journals Limonin Enhances the Antifungal Activity of Eugenol Nanoemulsion against Penicillium Italicum In Vitro and In Vivo Tests

2021 ◽  
Vol 9 (5) ◽  
pp. 969
Author(s):  
Yi Li ◽  
Runan Zhao ◽  
Yan Li ◽  
Zhiqin Zhou

Penicillium italicum, the cause of citrus blue mold, is a pathogenic fungus that seriously affects the postharvest quality of citrus fruit and causes serious economic loss. In this study, a eugenol nanoemulsion containing limonin, an antimicrobial component from citrus seeds, was prepared using a high-pressure microfluidizer and the antifungal activity of the nanoemulsions against P. italicum was evaluated based on the conidial germination rate, mycelial growth, and scanning electron microscopy analysis. The results showed that the minimum inhibitory concentration and the inhibition rate of limonin-loaded eugenol nanoemulsion was 160 μg/mL and 59.21%, respectively, which was more potent than that of the limonin-free eugenol emulsion. After treatment with the nanoemulsions, the integrity of the P. italicum cell membrane was disrupted, the cell morphology was abnormal, and the leakage of nucleic acid and protein was observed. In addition, the challenge test on citrus fruits revealed that the limonin-loaded eugenol emulsion inhibited citrus infection for longer periods, with an infection rate of 29.2% after 5 days. The current research shows that nanoemulsions containing limonin and eugenol have effective antifungal activity against P. italicum, and may be used as a substitute for inhibiting blue mold in citrus fruits.

2013 ◽  
Vol 76 (10) ◽  
pp. 1761-1766 ◽  
Author(s):  
GÜLTEN TİRYAKİ GÜNDÜZ ◽  
FIKRET PAZIR

In this study, the effects of UV-C on two of the main wound pathogens of citrus fruits, Penicillium digitatum and Penicillium italicum, were investigated with different inoculation methods in vitro and on oranges. P. digitatum and P. italicum spores were inoculated onto the surface of potato dextrose agar or oranges using spread, spot, wound, and piercing inoculation methods. UV-C treatment for 1 min from a working distance of 8 cm reduced the numbers of P. italicum and P. digitatum by about 3.9 and 5.3 log units, respectively, following spread inoculation under in vitro conditions. Significant reductions were obtained after 1-min UV-C treatments of the tested fungi following inoculation using the spread and spot methods. With inoculation by the wound and piercing methods, the tested spores were not inactivated completely even after 10- and 20-min treatment times, respectively. The application of UV-C (7.92 kJ m−2) on oranges reduced the percentage of oranges infected at least threefold compared with the rate of infection in the untreated control samples. UV-C irradiation could effectively inactivate spores of P. italicum and P. digitatum inoculated by the spread plate and spot inoculation methods under in vitro and in vivo conditions. On the other hand, because of the low penetration ability of UV-C light, the tested fungi were not completely inactivated following inoculation with the wound and piercing methods. UV-C treatment has potential for use in surface decontamination of citrus fruits.


Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 363 ◽  
Author(s):  
Chunxiao Yin ◽  
Hong Zhu ◽  
Yueming Jiang ◽  
Yang Shan ◽  
Liang Gong

The Dicer protein is one of the most important components of RNAi machinery because it regulates the production of small RNAs (sRNAs) in eukaryotes. Here, Dicer1-like gene (Pit-DCL1) and Dicer2-like gene (Pit-DCL2) RNAi transformants were generated via pSilent-1 in Penicillium italicum (Pit), which is the causal agent of citrus blue mold. Neither transformant showed a change in mycelial growth or sporulation ability, but the pathogenicity of the Pit-DCL2 RNAi transformant to citrus fruits was severely impaired, compared to that of the Pit-DCL1 RNAi transformant and the wild type. We further developed a citrus wound-mediated RNAi approach with a double-stranded fragment of Pit-DCL2 generated in vitro, which achieved an efficiency in reducing Pi-Dcl2 expression and virulence that was similar to that of protoplast-mediated RNAi in P. italicum, suggesting that this approach is promising in the exogenous application of dsRNA to control pathogens on the surface of citrus fruits. In addition, sRNA sequencing revealed a total of 69.88 million potential sRNAs and 12 novel microRNA-like small RNAs (milRNAs), four of which have been predicated on target innate immunity or biotic stress-related genes in Valencia orange. These data suggest that both the Pit-DCL1 and Pit-DCL2 RNAi transformants severely disrupted the biogenesis of the potential milRNAs, which was further confirmed for some milRNAs by qRT-PCR or Northern blot analysis. These data suggest the sRNAs in P. italicum that may be involved in a molecular virulence mechanism termed cross-kingdom RNAi (ck-RNAi) by trafficking sRNA from P. italicum to citrus fruits.


2020 ◽  
Vol 8 (4) ◽  
pp. 536
Author(s):  
Chuying Chen ◽  
Jinyin Chen ◽  
Chunpeng Wan

The current study aimed to examine the in vitro and in vivo antifungal potential of pinocembrin-7-glucoside (P7G). P7G is an antifungal flavanone glycoside isolated from Ficus hirta Vahl. fruit against Penicillium italicum, a causative pathogen of blue mold disease in citrus fruit, and this study elucidates its possible action mechanism. P7G had a prominent mycelial growth inhibitory activity against P. italicum, with an observed half maximal effective concentration, minimum inhibitory concentration and minimum fungicidal concentration of 0.08, 0.2, and 0.8 g/L, respectively. The data from the in vivo test show that P7G significantly reduced blue mold symptoms and disease development of P. italicum in artificially inoculated “Newhall” navel orange. Compared to the control, increases in the cell membrane permeability of P. italicum supernatant and decreases in the intracellular constituent (e.g., soluble protein, reducing sugar, and total lipid) contents of P. italicum mycelia were identified, supporting scanning electron microscopy and transmission electron microscopy observations. Furthermore, a marked decline in both chitin and glucanase contents of P. italicum mycelia treated with P7G was induced by increasing its related degrading enzyme activities, suggesting that the cell wall structure was destroyed. The current study indicated that P7G may be a novel alternative for reducing blue mold by suppressing mycelial growth of P. italicum via a cell membrane/wall-targeting mechanism.


2017 ◽  
Vol 2 (3) ◽  
pp. 147-153 ◽  
Author(s):  
Askarne L. ◽  
H. Boubaker ◽  
E. H. Boudyach ◽  
A. Ait Ben Aoumar

The aim of this study was to find an alternative to the chemical fungicide currently used in the control of postharvest citrus diseases. The antifungal activity of 10 salt compounds, considered as common food additives was assayed in in vitro and in vivo trials against Penicillium italicum, causal agent of citrus blue mold. Among the 10 tested salt compounds, sodium carbonate, ammonium carbonate, copper sulfate, sodium EDTA and sodium metabisulfite completely inhibited mycelial growth of Penicillium italicum at 20 mM. Colony growth of P. italicum on pH adjusted medium was evaluated. Results indicate that P. italicum can grow on both acidic and alkaline pH, with the optimum growth occurred in the range of 4.0 and 8.0. Results of the in vivo trials with tested salt compounds indicate that sodium metabisulfite (100 and 200 mM), boric acid (400 mM), sodium salicylate and sodium sulfite (200, 300 and 400 mM) completely inhibited blue mold development on citrus fruit. Boric acid (400 mM) and sodium metabisulfite (100 mM) gave the best results as they completely inhibited the fungus development without damaging fruit rind. Such healthy products therefore may represent a sustainable alternative to the use of chemical fungicides for controlling postharvest diseases of citrus fruit.


2013 ◽  
Vol 2 (1) ◽  
pp. 83-90 ◽  
Author(s):  
LU Bashir ◽  
IB Gashua ◽  
MA Isa ◽  
A Ali

The antifungal activity of aqueous and ethanol extracts obtained from seed and leaf of Jatropha curcas were investigated using agar incorporation method in vitro against Aspergillus niger, a microbe known to be resistant to some chemical agents. Pathogenicity test revealed that A. niger was the pathogenic fungus that cause black mould rot of onion bulbs. The growth of A. niger was markedly suppressed by aqueous and ethanol extracts of leaf and seed, 65.7 and 57.0% at 160 mg/ml. The extracts at low concentration did not show considerable activity against the fungus except leaf ethanol extract 53.3% at 40 mg/ml.The in vivo study showed that aqueous extracts of seed and leaf reduced rot development, 59.4 and 54.4 % in onion bulbs. Highest rot inhibition 66.3 was obtained at 160 mg/ml seed extract.The result of the study suggest the potentials of J. curcas extracts as fungicidal agent that could be useful in management of black mould rot of onion bulbs caused by Aspergillus niger. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 83-90 DOI: http://dx.doi.org/10.3126/ije.v2i1.9211


2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.


2017 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Mulyati Mulyati ◽  
Suryati Suryati ◽  
Irfani Baga

The study aims to isolate, characterize, and examine probiotic bacteria's inhibitory ability against Vibrio harveyi bacteria, both in-vitro and in vivo. Methods used in the study consist of 1) An Isolation of Candidate Probiotic Bacteria, 2) An Antagonistic Test of Candidate Probiotic Bacteria in vitro, 3) An Identification of Bacteria, 4) A Pathogenicity Test of Candidate Probiotic Bacteria, 5) An Antagonistic Test of Candidate Probiotic Bacteria against V. harveyi in vivo. According to the isolation of candidate probiotic bacteria, there are 18 isolated candidate probiotic. After being tested for its inhibitory ability in vitro, there are 8 isolates with zone of inhibition as follows: isolate MM 7 from intestine (22 mm), isolate MM 6 from intestine (12 mm), isolate MM 10 from sea water (10 mm), isolate MM 5 from intestine (9 mm), isolate MM 4 from intestine (8 mm), isolate MM 3 from intestine (7 mm), isolate MM 2.2 from intestine (7 mm), isolate MM 2.1 from intestine (7 mm). Eight genera of the candidate probiotic bacteria is derived from Portunid crab, they are Staphylococcus, Streptococcus, bacillus, vibrio, Alcaligenes, Lactobacillus, micrococcus. Before proceeding the V. harveyi bacterial challenge test in vivo, three potential isolates consisting of MM6, MM7 and MM10 as the probiotic bacteria are pathogenicity-tested against V. harveyi. The survival rate of Portunid crab on pathogenicity test using MM6, MM7 and MM10 generates 91.11-100%, while the control generates 100% survival rate. Variance analysis result through post-hoc Tukey's Honest Significant Difference (HSD) test at 95% confidence interval indicates that isolate MM7 and MM10 are significantly able to increase hatchling Portunid crab's survival rate.


2020 ◽  
Vol 8 (10) ◽  
pp. 1627
Author(s):  
Tecla Ciociola ◽  
Pier Paolo Zanello ◽  
Tiziana D’Adda ◽  
Serena Galati ◽  
Stefania Conti ◽  
...  

The growing problem of antimicrobial resistance highlights the need for alternative strategies to combat infections. From this perspective, there is a considerable interest in natural molecules obtained from different sources, which are shown to be active against microorganisms, either alone or in association with conventional drugs. In this paper, peptides with the same sequence of fragments, found in human serum, derived from physiological proteins, were evaluated for their antifungal activity. A 13-residue peptide, representing the 597–609 fragment within the albumin C-terminus, was proved to exert a fungicidal activity in vitro against pathogenic yeasts and a therapeutic effect in vivo in the experimental model of candidal infection in Galleria mellonella. Studies by confocal microscopy and transmission and scanning electron microscopy demonstrated that the peptide penetrates and accumulates in Candida albicans cells, causing gross morphological alterations in cellular structure. These findings add albumin to the group of proteins, which already includes hemoglobin and antibodies, that could give rise to cryptic antimicrobial fragments, and could suggest their role in anti-infective homeostasis. The study of bioactive fragments from serum proteins could open interesting perspectives for the development of new antimicrobial molecules derived by natural sources.


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