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Scientific Reports Jan 2020We aimed to develop a consortium of starter culture of effective microorganisms to prepare doenjang, a traditional Korean fermented food. Different ratios of Bacillus...
Effect of Rhizopus nigricans (Rhizopus stolonifera)-based novel starter culture on quality and safety attributes of doenjang, a traditional Korean soybean fermented food product.
We aimed to develop a consortium of starter culture of effective microorganisms to prepare doenjang, a traditional Korean fermented food. Different ratios of Bacillus subtilis TKSP 24 (B), Aspergillus oryzae complex (A), Rhizopus nigricans (also named as Rhizopus stolonifera) (R), and Mucor racemosus 15 (M15) were selected as meju starter cultures to produce doenjang with improved quality. Microbial strain combinations (B: A: R and B: M15: R) were mixed separately at three different ratios [1:1:1 (w/w), 1:0.5:1.5 (w/w), and 1:1.5:0.5 (w/w)] to prepare BAR-1, BAR-2, BAR-3, BM15R-1, BM15R-2, and BM15R-3 doenjang samples. Quantitative analyses included free amino acids, free sugar, volatile and non-volatile organic acids, cellular antioxidant activity along with the presence of biogenic amines and aflatoxins, and microbial counts. Total free amino acids responsible for the sweet taste of doenjang were highest in BAR-2 (322.50 mg/100 g) and BM15R-3 (320.07 mg/100 g). Total volatile organic acid was highest in BAR-1 compared to other preparations. All doenjang samples had biogenic amines, especially histamine, below the toxicity level (500 mg/kg). Also, the aflatoxin and hazardous microbial count in the tested doenjang samples were below the level of toxicity. The findings suggest that use of multiple microbial strains in combination with R. nigricans as a starter culture could be a novel and effective approach to improve the nutrition and safety of fermented soybean food products of doenjang.
Topics: Aflatoxins; Amino Acids; Biogenic Amines; Fermentation; Food Microbiology; Food Safety; Quality Control; Republic of Korea; Rhizopus; Soy Foods; Glycine max
PubMed: 31974506
DOI: 10.1038/s41598-019-57382-y -
Clinical Infectious Diseases : An... Feb 2012Mucormycosis is a life-threatening infection that occurs in patients who are immunocompromised because of diabetic ketoacidosis, neutropenia, organ transplantation,... (Review)
Review
Mucormycosis is a life-threatening infection that occurs in patients who are immunocompromised because of diabetic ketoacidosis, neutropenia, organ transplantation, and/or increased serum levels of available iron. Because of the increasing prevalence of diabetes mellitus, cancer, and organ transplantation, the number of patients at risk for this deadly infection is increasing. Despite aggressive therapy, which includes disfiguring surgical debridement and frequently adjunctive toxic antifungal therapy, the overall mortality rate is high. New strategies to prevent and treat mucormycosis are urgently needed. Understanding the pathogenesis of mucormycosis and the host response to invading hyphae ultimately will provide targets for novel therapeutic interventions. In this supplement, we review the current knowledge about the virulence traits used by the most common etiologic agent of mucormycosis, Rhizopus oryzae. Because patients with elevated serum levels of available iron are uniquely susceptible to mucormycosis and these infections are highly angioinvasive, emphasis is placed on the ability of the organism to acquire iron from the host and on its interactions with endothelial cells lining blood vessels. Several promising therapeutic strategies in preclinical stages are identified.
Topics: Diabetic Ketoacidosis; Endothelial Cells; Genes, Fungal; Host-Pathogen Interactions; Humans; Immunocompromised Host; Iron; Mucormycosis; Phagocytes; Rhizopus; Risk Factors; Virulence Factors
PubMed: 22247441
DOI: 10.1093/cid/cir865 -
Virulence Nov 2017
Topics: Humans; Mucormycosis; Rhizopus
PubMed: 28806142
DOI: 10.1080/21505594.2017.1364335 -
G3 (Bethesda, Md.) May 2018Phylogenomic approaches have the potential to improve confidence about the inter-relationships of species in the order Mucorales within the fungal tree of life. species...
Phylogenomic approaches have the potential to improve confidence about the inter-relationships of species in the order Mucorales within the fungal tree of life. species are especially important as plant and animal pathogens and bioindustrial fermenters for food and metabolite production. A dataset of 192 orthologous genes was used to construct a phylogenetic tree of 21 strains, classified into four species isolated from habitats of industrial, medical and environmental importance. The phylogeny indicates that the genus consists of three major clades, with as the basal species and the sister lineage to and two closely related species and A comparative analysis of the mating type locus across reveals that its structure is flexible even between different species in the same genus, but shows similarities between and other mucoralean fungi. The topology of single-gene phylogenies built for two genes involved in mating is similar to the phylogenomic tree. Comparison of the total length of the genome assemblies showed that genome size varies by as much as threefold within a species and is driven by changes in transposable element copy numbers and genome duplications.
Topics: DNA Transposable Elements; Genes, Mating Type, Fungal; Genome Size; Genome, Fungal; Genomics; Likelihood Functions; Open Reading Frames; Phylogeny; Rhizopus; Species Specificity; Whole Genome Sequencing
PubMed: 29674435
DOI: 10.1534/g3.118.200235 -
The ISME Journal Jul 2020Rhizopus microsporus is an early-diverging fungal species with importance in ecology, agriculture, food production, and public health. Pathogenic strains of R....
Rhizopus microsporus is an early-diverging fungal species with importance in ecology, agriculture, food production, and public health. Pathogenic strains of R. microsporus harbor an intracellular bacterial symbiont, Mycetohabitans (formerly named Burkholderia). This vertically transmitted bacterial symbiont is responsible for the production of toxins crucial to the pathogenicity of Rhizopus and remarkably also for fungal reproduction. Here we show that R. microsporus can live not only in symbiosis with bacteria but also with two viral members of the genus Narnavirus. Our experiments revealed that both viruses replicated similarly in the growth conditions we tested. Viral copies were affected by the developmental stage of the fungus, the substrate, and the presence or absence of Mycetohabitans. Absolute quantification of narnaviruses in isolated asexual sporangiospores and sexual zygospores indicates their vertical transmission. By curing R. microsporus of its viral and bacterial symbionts and reinfecting bacteria to reestablish symbiosis, we demonstrate that these viruses affect fungal biology. Narnaviruses decrease asexual reproduction, but together with Mycetohabitans, are required for sexual reproductive success. This fungal-bacterial-viral system represents an outstanding model to investigate three-way microbial symbioses and their evolution.
Topics: Burkholderia; Rhizopus; Spores, Fungal; Symbiosis
PubMed: 32269378
DOI: 10.1038/s41396-020-0638-y -
Journal of Infection and Public Health Oct 2021This review aimed to study molecular mechanisms for high incidence of life-threatening mucormycosis infection in COVID19 cases during second wave of SARS CoV2 pandemic... (Review)
Review
This review aimed to study molecular mechanisms for high incidence of life-threatening mucormycosis infection in COVID19 cases during second wave of SARS CoV2 pandemic in India. Hyperglycaemia, impaired immunity, acidosis, raised ferritin, glucocorticoid therapy, and COVID19 specific other factors have been implicated in pathogenesis of COVID19 associated mucormycosis (CAMM). Endoplasmic reticulum chaperone 'Glucose Related Protein 78' (GRP78), also involved in SARS CoV2 entry, is the host receptor for invasion by Mucorales. GRP78 is over-expressed by SARS CoV2, hyperglycaemia and ferritin. Delta variant of SARS CoV2 and indiscriminate use of steroids were distinguishing features of second wave and appear to upregulate GRP78 through intricate interplay between internal and external milieu. Common invasive fungal infections like candidiasis and aspergillosis, not utilizing GRP78 as receptor, were inconspicuous. Further molecular research to unravel mechanisms involved in the pathogenesis of CAMM shall effectively complement existing strategies for its prevention and treatment.
Topics: COVID-19; Endoplasmic Reticulum Chaperone BiP; Humans; Mucormycosis; Rhizopus; SARS-CoV-2
PubMed: 34538732
DOI: 10.1016/j.jiph.2021.09.004 -
Journal of Food Protection May 2023Electron beam irradiation is a physical fungicidal technique that has emerged as a potential application in China. However, its antifungal activity and mechanism against...
Electron beam irradiation is a physical fungicidal technique that has emerged as a potential application in China. However, its antifungal activity and mechanism against Rhizopus oryzae have not been reported. Thus, this study aimed to investigate the antifungal activity and mechanism of electron beam irradiation of R. oryzae. The antifungal activity analysis showed that the D value and complete elimination dose of R. oryzae irradiated by electron beam were 1.73 kGy and 8.08 kGy, respectively. Electron beam irradiation has a strong inhibitory effect on the filamentous biomass of R. oryzae. To reveal the antifungal mechanism of electron beam against R. oryzae, this study analyzed the dynamic changes in the cell wall, cell membrane, and oxidative stress induced by different irradiation doses. The results showed that electron beam irradiation destroyed the cell wall structure of R. oryzae, increasing chitinase activity and decreasing chitin content. Cell membrane integrity is disrupted, increasing relative conductivity, decreasing pH values, and decreasing soluble protein content. Electron beam irradiation causes oxidative stress in cells, increasing HO content, decreasing antisuperoxide anion activity, decreasing DPPH free radical scavenging activity, and inhibiting defense enzyme (CAT and SOD) activity. This phenomenon indicates that electron beams can cause structural damage to and metabolic dysfunction of cells and disorders of redox homeostasis, which may be the main cause of growth inhibition and cell death in R. oryzae.
Topics: Antifungal Agents; Rhizopus oryzae; Hydrogen Peroxide; Electrons; Rhizopus
PubMed: 36989859
DOI: 10.1016/j.jfp.2023.100070 -
Journal of Applied Microbiology Jan 2018This study aimed to investigate the antifungal mechanism of carvacrol and eugenol to inhibit Rhizopus stolonifer and the control of postharvest soft rot decay in peaches.
AIMS
This study aimed to investigate the antifungal mechanism of carvacrol and eugenol to inhibit Rhizopus stolonifer and the control of postharvest soft rot decay in peaches.
METHODS AND RESULTS
To investigate the antifungal mechanism, the effects of carvacrol and eugenol on the mycelium growth, leakages of cytoplasmic contents, mycelium morphology, cell membrane and membrane composition of R. stolonifer were studied. Carvacrol and eugenol both exhibited dose-dependent antifungal activity against R. stolonifer, carvacrol at a concentration of 2 μl per plant and eugenol at a concentration of 4 μl per plant inhibited fungal growth completely. The two essential oils (EOs) increased cell membrane penetrability and caused the leakage of cytoplasm, nucleic acid and protein content. The observation using scanning electron microscopy and fluorescent microscopy showed modification of the hyphal morphology and breakage of the cell plasma membrane. Decreased ergosterol contents confirmed that the two EOs could destroy the membrane of R. stolonifer. For the in vivo test, the inhibition of soft rot disease and the induction of defence-related enzymes were investigated. Carvacrol and eugenol significantly reduced the incidence and severity of soft rot decay in inoculated peaches. The best treatments for controlling soft rot decay were obtained at 0·5 μl l for carvacrol and 1 μl l for eugenol. The activities of defence-related enzymes in peaches were also enhanced by fumigation with two EOs.
CONCLUSION
This study showed that carvacrol and eugenol could effectively inhibit the growth of R. stolonifer in vitro and successfully control the incidence of soft rot decay in honey peaches.
SIGNIFICANCE AND IMPACT OF THE STUDY
The above findings may be the main antifungal mechanism of carvacrol and eugenol on R. stolonifer. Furthermore, carvacrol and eugenol are helpful for their commercial application on the preservation of fresh fruit.
Topics: Cymenes; Eugenol; Fruit; Fungicides, Industrial; Hyphae; Monoterpenes; Mycelium; Oils, Volatile; Plant Diseases; Prunus persica; Rhizopus
PubMed: 29044849
DOI: 10.1111/jam.13612 -
Current Biology : CB Mar 2022Opportunistic infections by environmental fungi are a growing clinical problem, driven by an increasing population of people with immunocompromising conditions. Spores...
Opportunistic infections by environmental fungi are a growing clinical problem, driven by an increasing population of people with immunocompromising conditions. Spores of the Mucorales order are ubiquitous in the environment but can also cause acute invasive infections in humans through germination and evasion of the mammalian host immune system. How they achieve this and the evolutionary drivers underlying the acquisition of virulence mechanisms are poorly understood. Here, we show that a clinical isolate of Rhizopus microsporus contains a Ralstonia pickettii bacterial endosymbiont required for virulence in both zebrafish and mice and that this endosymbiosis enables the secretion of factors that potently suppress growth of the soil amoeba Dictyostelium discoideum, as well as their ability to engulf and kill other microbes. As amoebas are natural environmental predators of both bacteria and fungi, we propose that this tri-kingdom interaction contributes to establishing endosymbiosis and the acquisition of anti-phagocyte activity. Importantly, we show that this activity also protects fungal spores from phagocytosis and clearance by human macrophages, and endosymbiont removal renders the fungal spores avirulent in vivo. Together, these findings describe a new role for a bacterial endosymbiont in Rhizopus microsporus pathogenesis in animals and suggest a mechanism of virulence acquisition through environmental interactions with amoebas.
Topics: Amoeba; Animals; Bacteria; Dictyostelium; Fungi; Humans; Mammals; Mice; Phagocytes; Rhizopus; Virulence; Zebrafish
PubMed: 35134329
DOI: 10.1016/j.cub.2022.01.028 -
Clinical Microbiology and Infection :... Oct 2009Zygomycosis refers to a group of uncommon and frequently fatal mycoses caused by fungi of the class Zygomycetes, the organisms of which are usually found in decaying... (Review)
Review
Zygomycosis refers to a group of uncommon and frequently fatal mycoses caused by fungi of the class Zygomycetes, the organisms of which are usually found in decaying organic matter. Disease can be transmitted by the inhalation of spores or by direct inoculation on disrupted skin or mucosa. For rare diseases such as zygomycosis, two or more cases occurring in a short time should be investigated as a probable epidemic. Twelve hospital outbreaks and two pseudoepidemics caused by Zygomycetes have been cited in the English literature. The first epidemic was recorded in 1977 and the last in 2008. Outbreaks have been reported in the USA, the UK and elsewhere in Europe. Cases have included cutaneous, disseminated, pulmonary and rhinocerebral disease. Species identified have included Rhizopus arrhizus, Rhizopus rhizopodiformis, Rhizopus microsporus, Rhizopus spp., Absidia corymbifera and Rhizomucor pusillius. Sources of infection have included Elastoplast adhesive bandage rolls, ventilation systems, wooden tongue depressors, karaya (plant-derived adhesive) ostomy bags, and water damage to a linen store and patient shower room. Patients have included cardiosurgery patients, renal transplant recipients, orthopaedic patients, adult leukaemia patients, intensive care unit neonates, immunocompromised haematology patients, and burn unit patients. Although zygomycosis outbreaks in the hospital environment are infrequent, a high index of suspicion should exist if necrotic lesions appear in proximity to a postoperative wound. Direct tissue examination and tissue culture and histopathology must be routinely performed.
Topics: Absidia; Cross Infection; Disease Outbreaks; Europe; Hospitals; Humans; Rhizomucor; Rhizopus; United States; Zygomycosis
PubMed: 19754759
DOI: 10.1111/j.1469-0691.2009.02982.x