scholarly journals Staphylococcus saprophyticus L-38 produces volatile 3,3-dimethyl-1,2-epoxybutane with strong inhibitory activity against Aspergillus flavus germination and aflatoxin production

2020 ◽  
Vol 13 (2) ◽  
pp. 247-258 ◽  
Author(s):  
A.D. Gong ◽  
G.J. Sun ◽  
Z.Y. Zhao ◽  
Y.C. Liao ◽  
J.B. Zhang

Controlling proliferation and aflatoxin production by Aspergillus flavus is a pressing challenge for global food safety and security. Marine bacterium Staphylococcus saprophyticus strain L-38 showed excellent antifungal activity toward A. flavus in vitro and in vivo. In sealed, non-contact confrontation assays, L-38 completely inhibited conidial germination and mycelial growth of A. flavus through the production of volatile organic compounds (VOCs). Gas chromatography-mass spectrometry identified 3,3-dimethyl-1,2-epoxybutane (3-DE) as the most abundant VOC (32.61% of total peak area, 78% matching). Exposure of A. flavus cultures to synthetic 3-DE similarly demonstrated strong inhibition of growth. Moreover, culture of L-38 in a sealed chamber with maize or peanuts artificially inoculated with A. flavus, at high water activity, resulted in significant inhibition of A. flavus germination and aflatoxin biosynthesis. Scanning electron microscopy of these samples revealed severe damage to conidial cells and hyphae compared to samples not exposed to L-38. L-38 also showed broad and effective antifungal activity toward eight other phytopathogenic fungi including Aspergillus niger, Fusarium verticillioides, Fusarium graminearum, Sclerotinia sclerotiorum, Rhizoctonia solani, Alternaria alternata, Monilinia fructicola, and Botrytis cinerea. This work introduces S. saprophyticus L-38 as a potential biocontrol agent and demonstrates the efficacy of the volatile 3-DE in the control of A. flavus and other destructive plant pathogens for post-harvest food safety.

Toxins ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 57 ◽  
Author(s):  
Fengqin Song ◽  
Qingru Geng ◽  
Xuewei Wang ◽  
Xiaoqing Gao ◽  
Xiaona He ◽  
...  

Aspergillus flavus is one of the most opportunistic pathogens invading many important oilseed crops and foodstuffs with such toxic secondary metabolites as aflatoxin (AF) and Cyclopiazonic acid. We previously used the DNA methylation inhibitor 5-azacytidine to treat with an AF-producing A. flavus A133 strain, and isolated a mutant (NT) of A. flavus, which displayed impaired abilities of AF biosynthesis and fungal development. In this study, gas chromatography–mass spectrometry (GC-MS) analysis was used to reveal the metabolic changes between these two strains. A total of 1181 volatiles were identified in these two strains, among which 490 volatiles were found in these two strains in vitro and 332 volatiles were found in vivo. The NT mutant was found to produce decreasing volatile compounds, among which most of the fatty acid-derived volatiles were significantly downregulated in the NT mutant compared to the A133 strain, which are important precursors for AF biosynthesis. Two antioxidants and most of the amino acids derived volatiles were found significantly upregulated in the NT mutant. Overall, our results reveal the difference of metabolic profiles in two different A. flavus isolates, which may provide valuable information for controlling infections of this fungal pathogen.


2019 ◽  
Vol 22 (2) ◽  
pp. 190-199 ◽  
Author(s):  
A. Sadeghi ◽  
M. Ebrahimi ◽  
B. Sadeghi ◽  
S. A. Mortazavi

Biocontrol of moulds by lactic acid bacteria (LAB) instead of antibiotics and chemical preservatives is a new approach in veterinary medicine. The aims of present research were to perform molecular identification of dominant sourdough LAB isolates and to evaluate their in vivo safety and in vitro antifungal properties for using as biopreservative agents. Sequencing results of PCR products led to identification of Lactobacillus reuteri and Pediococcus diacetilactis as LAB isolates. Antifungal activity of the isolates and their cell-free culture filtrate (CCF) were also confirmed against aflatoxigenic Aspergillus flavus, respectively by overlay and spore spot methods. Accordingly, antagonistic effect of P. diacetilactis and its CCF were significantly (P<0.05) higher than L. reuteri and CCF of mentioned LAB isolate. Clinical chemistry and haematological findings in mice fed LAB demonstrated also insignificant difference vs control mice and were in the normal range, which confirmed the safety of LAB isolates. By considering the importance of safe, food grade biocontrol agents, L. reuteri and P. diacetilactis isolates and their CCF may be considered as an alternative for antibiotics and other chemical preservatives in food and feed processing chain


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.


2020 ◽  
Vol 6 (4) ◽  
pp. 383
Author(s):  
Premila Narayana Achar ◽  
Pham Quyen ◽  
Emmanuel C. Adukwu ◽  
Abhishek Sharma ◽  
Huggins Zephaniah Msimanga ◽  
...  

Aspergillus species are known to cause damage to food crops and are associated with opportunistic infections in humans. In the United States, significant losses have been reported in peanut production due to contamination caused by the Aspergillus species. This study evaluated the antifungal effect and anti-aflatoxin activity of selected plant-based essential oils (EOs) against Aspergillus flavus in contaminated peanuts, Tifguard, runner type variety. All fifteen essential oils, tested by the poisoned food technique, inhibited the growth of A. flavus at concentrations ranging between 125 and 4000 ppm. The most effective oils with total clearance of the A. flavus on agar were clove (500 ppm), thyme (1000 ppm), lemongrass, and cinnamon (2000 ppm) EOs. The gas chromatography-mass spectrometry (GC-MS) analysis of clove EO revealed eugenol (83.25%) as a major bioactive constituent. An electron microscopy study revealed that clove EO at 500 ppm caused noticeable morphological and ultrastructural alterations of the somatic and reproductive structures. Using both the ammonia vapor (AV) and coconut milk agar (CMA) methods, we not only detected the presence of an aflatoxigenic form of A. flavus in our contaminated peanuts, but we also observed that aflatoxin production was inhibited by clove EO at concentrations between 500 and 2000 ppm. In addition, we established a correlation between the concentration of clove EO and AFB1 production by reverse-phase high-performance liquid chromatography (HPLC). We demonstrate in our study that clove oil could be a promising natural fungicide for an effective bio-control, non-toxic bio-preservative, and an eco-friendly alternative to synthetic additives against A. flavus in Georgia peanuts.


Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 155
Author(s):  
Jannatul Nasma Rupa Moni ◽  
Md. Adnan ◽  
Abu Montakim Tareq ◽  
Md. Imtiazul Kabir ◽  
A.S.M. Ali Reza ◽  
...  

Syzygium fruticosum (SF), a valuable Bangladeshi fruit, is considered an alternative therapeutic agent. Mainly, seeds are used as nutritional phytotherapy to ease physical and mental status by preventing chronic diseases. Here, we scrutinized the S. fruticosum seed’s fundamental importance in traditional medicine by following an integrated approach combining in vivo, in vitro, and in silico studies. The SF was fractionated with different solvents, and the ethyl acetate fraction of SF (EaF-SF) was further studied. Mice treated with EaF-SF (200 and 400 mg/kg) manifested anxiolysis evidenced by higher exploration in elevated plus maze and hole board tests. Similarly, a dose-dependent drop of immobility time in a forced swimming test ensured significant anti-depressant activity. Moreover, higher dose treatment exposed reduced exploratory behaviour resembling decreased movement and prolonged sleeping latency with a quick onset of sleep during the open field and thiopental-induced sleeping tests, respectively. In parallel, EaF-SF significantly (p < 0.001) and dose-dependently suppressed acetic acid and formalin-induced pain in mice. Also, a noteworthy anti-inflammatory activity and a substantial (p < 0.01) clot lysis activity (thrombolytic) was observed. Gas chromatography-mass spectrometry (GC–MS) analysis resulted in 49 bioactive compounds. Among them, 12 bioactive compounds with Lipinski’s rule and safety confirmation showed strong binding affinity (molecular docking) against the receptors of each model used. To conclude, the S. fruticosum seed is a prospective source of health-promoting effects that can be an excellent candidate for preventing degenerative diseases.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 976
Author(s):  
Natalia Langa-Lomba ◽  
Laura Buzón-Durán ◽  
Pablo Martín-Ramos ◽  
José Casanova-Gascón ◽  
Jesús Martín-Gil ◽  
...  

In the work presented herein, we analyze the efficacy of three basic substances that comply with European Regulation (EC) No 1107/2009, namely chitosan, horsetail (Equisetum arvense L.) and nettle (Urtica dioica L.), for the control of grapevine trunk diseases (GTDs) in organic farming. The E. arvense and U. dioica aqueous extracts, prepared according to SANCO/12386/2013 and SANTE/11809/2016, have been studied by gas chromatography–mass spectrometry (GC-MS), identifying their main active constituents. The three basic substances, either alone or in combination (forming conjugate complexes), have been tested in vitro against eight Botryosphaeriaceae species, and in vivo, in grafted plants artificially inoculated with Neofusicoccum parvum and Diplodia seriata. A clear synergistic behavior between chitosan and the two plant extracts has been observed in the mycelial growth inhibition tests (resulting in EC90 values as low as 208 μg·mL−1 for some of the isolates), and statistically significant differences have been found in terms of vascular necroses lengths between treated and non-treated plants, providing further evidence of aforementioned synergism in the case of D. seriata. The reported data supports the possibility of extending the applications of these three basic substances in Viticulture beyond the treatment of mildew.


2021 ◽  
Vol 7 (3) ◽  
pp. 195
Author(s):  
Amr H. Hashem ◽  
Amer M. Abdelaziz ◽  
Ahmed A. Askar ◽  
Hossam M. Fouda ◽  
Ahmed M. A. Khalil ◽  
...  

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.


Author(s):  
Anjali P ◽  
Vimalavathini R

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease which mainly targets synovial membrane during its disease pathogenesis. Available therapeutic drugs for the treatment of RA provide only symptomatic relief and are associated with severe side effects. Herbal plants comprise many active biological compounds that cure the disease with minimal adverse effects. Pyrenacantha volubilis is a climber and member of Icacinaceae family. Gas chromatography- mass spectrometry (GC-MS) analysis of ethanolic extracts of leaves of Pyrenacantha volubilis (EEPV) reveals the presence of 2-isopropyl-5-methylcyclohexyl 3-(1-(4- chlorophenyl)-3-oxobutyl)-coumarin-4-yl carbonate and 1-naphthalenepropanol, alpha-ethyldecahydro-5- (hydroxymethyl)-alpha,5,8A-trimethyl-2-methyl phytoconstitutents. Hence these compounds were docked with various pathological mediators of RA using Autodock 4.2. The docking results unveils that these compounds had better binding energy against inflammatory, oxidative stress and receptor for advanced glycation end products (RAGE) mediators that plays a pivotal role in the progression of RA. However, this study warrants further in- vitro and in-vivo studies to be carried out to establish the anti-inflammatory and anti-arthritic activity of selected phytoconstitutents.


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