Actinomucor Elegans Research Articles

Update on Actinomucor elegans, a mucormycete infrequently detected in human specimens: how combined microbiological tools contribute efficiently to a more accurate medical care

Actinomucor elegans is a fungus belonging to mucormycetes and is still probably underdiagnosed due to misidentification. Based on a recent first case of Actinomucor elegans sinusitis in Europe, in an immunocompromised patient under voriconazole treatment, this paper aims to summarize knowledge about A. elegans mucormycoses. Even if the diagnosis of mucormycosis was made using traditional mycology techniques, precise identification of the fungus could only be achieved using molecular tools. In this observation, the galactomannan dosage was positive until the introduction of treatment and surgical debridement. The patient experienced no relapse after one year. By reviewing the four previous A. elegans reported cases and describing the mycological characteristics of this species, we highlight the need to use a combination of tools to improve the diagnostic strategy in such rare and life-threatening clinical situations.

Interspecies-cooperations of abutilon theophrasti with root colonizing microorganisms disarm BOA-OH allelochemicals

ABSTRACTA facultative, microbial micro-community colonizing roots of Abutilon theophrasti Medik. supports the plant in detoxifying hydroxylated benzoxazolinones. The root micro-community is composed of several fungi and bacteria with Actinomucor elegans as a dominant species. The yeast Papiliotrema baii and the bacterium Pantoea ananatis are actively involved in the detoxification of hydroxylated benzoxazolinones by generating H2O2. At the root surface, laccases, peroxidases and polyphenol oxidases cooperate for initiating polymerization reactions, whereby enzyme combinations seem to differ depending on the hydroxylation position of BOA-OHs. A glucosyltransferase, able to glucosylate the natural benzoxazolinone detoxification intermediates BOA-5- and BOA-6-OH, is thought to reduce oxidative overshoots by damping BOA-OH induced H2O2 generation. Due to this detoxification network, growth of Abutilon theophrasti seedlings is not suppressed by BOA-OHs. Polymer coats have no negative influence. Alternatively, quickly degradable 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one can be produced by the micro-community member Pantoea ananatis at the root surfaces. The results indicate that Abutilon theophrasti has evolved an efficient strategy by recruiting soil microorganisms with special abilities for different detoxification reactions which are variable and may be triggered by the allelochemical´s structure and by environmental conditions.

Impact of selected fungi from an artificial diet on the growth and development of Drosophila suzukii (Diptera: Drosophilidae)

Drosophila suzukii (Diptera: Drosophilidae) is one of the very few Drosophila species which are able to lay eggs and feed on healthy ripening fruit. Adults and larvae are all able to obtain the nutrition in the decaying food, which will generate many microorganisms. However, the relationship between D. suzukii and microorganism is poorly understood. In this study, 13 species of fungi were identified in an artificial diet fed by D. suzukii. Short-term and continuously life table experiments were conducted to determine the impact of three of these fungus species including Geotrichum candidum, Talaromyces minioluteus and Actinomucor elegans on the growth and development of Drosophila suzukii. Results revealed that, compared to the control, G. candidum, T. minioluteus and A. elegans increased the mortality of D. suzukii adults in the short time, while extended the developmental time of pupal D. suzukii by 18.00%, 16.22% and 26.44%, respectively in the life table experiment. T. minioluteus reduced the total longevity of D. suzukii by 15.52%, while A. elegans enhanced the total longevity by 25.96%. G. candidum and A. elegans increased the fecundity by more than two folds. T. minioluteus elongated the mean generation time (T) by 31.34%, whereas G. candidum shortened it by 15.26% but increased the net reproductive rate (R0) by 217.76%, intrinsic rate of increase (r) by 88.89% and finite rate of increase (λ) by 9.17%. It was concluded that G. candidum and A. elegans significantly had the beneficial effect on the growth and reproduction of D. suzukii, however, T. minioluteus had the negative effect on D. suzukii. Our results could provide a new integrated pest management strategy for D. suzukii which would be discussed in this study.

Enhancing the functional properties of soymilk residues (okara) by solid-state fermentation with Actinomucor elegans

ABSTRACTIn this study, the food-grade fungal strain DCY-1 was isolated from Chinese traditional fermented soymilk residues (okara) and identified as Actinomucor elegans. The novel strain was used in the solid-state fermentation (SSF) of okara to improve their functional properties. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and reverse-phase high-performance liquid chromatography (RP-HPLC) analyses showed that okara proteins were degraded into peptides during fermentation. SSF okara showed high antioxidant activities, which included reducing power, ferrous ion-chelating activity, and scavenging effect of DPPH, ABTS, and hydroxyl radicals. Compared with the control, the antioxidant activities mentioned above increased by 4.29, 2.32, 3.45, 1.55, and 1.63-fold, respectively. SSF okara also showed a significantly higher ACE-inhibitory activity (61.17% ± 0.94%) at the end of fermentation. Therefore, SSF can be employed as a valuable process to obtain bioactive ingredients from okara, which would encourage their utilization in the formulation of value-added functional foods.

Physicochemical characteristics, protein hydrolysis, and textual properties of surimi during fermentation with Actinomucor elegans

ABSTRACTSolid-fermentation is a promising way of producing novel surimi-based food. In the present study, changes in physicochemical characteristics, protein hydrolysis, and textual properties of surimi during the fermentation, including pehtze preparation, salting, and ripening stages, were studied. The protease produced by Actinomucor elegans led to continuous hydrolysis of surimi protein, reflected from the high value of protease activity which reached 69.34 U/g after pehtze preparation stage, the decrease of protein bands intensity in sodium dodecyl sulfate polyacrylamide gel electrophoresis image especially for bands of 200, 43, and 36 KDa, and the increasing contents of free amino acids and trichloroacetic acid-soluble nitrogen. Hardness, springiness, and cohesiveness of the surimi all decreased during pehtze preparation stage, increased after salting, and decreased again after ripening, while adhesiveness kept increasing until the ripening stage started. Scanning electron microscopy images showed a dense and soft microstructure of surimi after ripening. The final surimi product showed high overall acceptability and no Enterobacteriaceae was detected.

Identification of Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Enzymatic Hydrolysates of Razor Clam Sinonovacula constricta.

Angiotensin I-converting enzyme (ACE) inhibitory activity of razor clam hydrolysates produced using five proteases, namely, pepsin, trypsin, alcalase, flavourzyme and proteases from Actinomucor elegans T3 was investigated. Flavourzyme hydrolysate showed the highest level of degree of hydrolysis (DH) (45.87%) followed by A. elegans T3 proteases hydrolysate (37.84%) and alcalase (30.55%). The A. elegans T3 proteases was observed to be more effective in generating small peptides with ACE-inhibitory activity. The 3 kDa membrane permeate of A. elegans T3 proteases hydrolysate showed the highest ACE-inhibitory activity with an IC50 of 0.79 mg/mL. After chromatographic separation by Sephadex G-15 gel filtration and reverse phase-high performance liquid chromatography, the potent fraction was subjected to MALDI/TOF-TOF MS/MS for identification. A novel ACE-inhibitory peptide (VQY) was identified exhibiting an IC50 of 9.8 μM. The inhibitory kinetics investigation by Lineweaver-Burk plots demonstrated that the peptide acts as a competitive ACE inhibitor. The razor clam hydrolysate obtained by A. elegans T3 proteases could serve as a source of functional peptides with ACE-inhibitory activity for physiological benefits.

Soy protein hydrolysates fermentation: Effect of debittering and degradation of major soy allergens

The debittering effect of induced liquid state fermentation (Lactobacillus perolens, Rhizopus oryzae, and Actinomucor elegans) on different soy protein hydrolysates has been investigated. The hydrolytic action was monitored by SDS-PAGE and degree of hydrolysis analyses. Sensory perception using quantitative descriptive analysis (QDA), employing multivariate statistical principal component analysis (PCA), techno-functional properties, and the microbial competitiveness (MALDI-TOF-MS) have been evaluated. SDS-PAGE profiles evidenced that the enzyme preparations degraded most of major soy allergens (β-conglycinin, glycinin), while subsequent fermentation did not further change the profiles. All strains investigated effectively reduced bitterness to a minimum of 0.7 on a 10-cm continuous scale (0 = no perception; 10 = strong perception) compared to non-fermented hydrolysates (2.8–8.0) and untreated soy protein isolate (2.8). Protein solubility, emulsifying and oil-binding capacity as well as foaming activity and gelation behaviour were enhanced depending on the protease used; subsequent fermentation further improved foaming stability and gelation concentration. PCA of descriptive sensory data revealed that fermentation apparently upgrade the organoleptic perception by effectively decreasing the bitter taste, simultaneously reducing the beany off-flavour of soy. Consequently, enzymatic hydrolysis combined with subsequent fermentation represents a promising method for the production of hypoallergenic soy hydrolysates with pleasant taste and great technofunctionality.

Organisms with potential to assist in the control of Helicoverpa armigera in Australian cotton production systems

Helicoverpa armigera was once considered the most important insect pest to Australian cotton production. The introduction of genetically modified cotton altered this status and made this insect pest control less chemically dependent, but resistance to the insecticidal compounds expressed in genetically modified cotton has evolved in laboratory-reared H. armigera populations and is shown to exist in natural populations. Preventing the development of resistance in field populations is complicated by the over wintering of potentially resistant individuals in the soil. Biocontrol may assist in reducing the population of resistant individuals. Several projects investigating the ecology of Australian cotton highlighted the existence of several native organisms with ability to limit the growth or utilise H. armigera as a host. The work reported here set about establishing the presence of such organisms in Australian cotton soils by recovering them from soil and farm-collected H. armigera that exhibited abnormal growth, disease or death. The recovered organisms were identified as the fungi Lecanicillium lecanii, Actinomucor elegans and several Aspergillus species. L. lecanii was subsequently shown to reduce moth emergence to 56% of the larvae to which it was applied. We also identified a species of Rhabditis nematode, which killed 34% of the larvae to which it was applied and reduced moth emergence to 28%. In light of these observations these organisms are reported as potential candidates for biological control of H. armigera.

Dynamics and Diversity of Microbial Community Succession of Surimi During Fermentation with Next-Generation Sequencing

Dynamics and diversity of microbial community succession of surimi during fermentation with Actinomucor elegans were analyzed by high-throughput sequencing. The results showed that Cyanobacteria represented by Streptophyta were found to have the highest diversity at the beginning of fermentation and then decreased sharply with the fermentation proceeded. Then, Proteobacteria became the most dominant phylum followed by Firmicutes with a relative abundance of 77.77% after 48 h of fermentation. Actinobacteria and Bacteroidetes were occasionally present. Enterobacteriaceae, Moraxellaceae, Xanthomonadaceae, Bacillaceae and Enterococcaceae were found to account for almost all the diversity during fermentation. Stenotrophomonas, Acinetobacter and Enterococcus were three dominant genera that were classified with the relative abundance of 18.19, 19.76 and 7.74% after 36 h of fermentation, respectively. The bacterial diversity of surimi decreased after 48 h of fermentation as some species gradually became dominant and some were almost undetectable. In addition, from the results of traditional microbiological analysis, counts of mesophilic aerobic bacteria, total enterobacteria, enterococci and Pseudomonas all increased with the change in pH value of surimi, which decreased from 7.16 to 5.93 during fermentation. Practical Applications Data about dynamics and diversity of microbial community succession in surimi during fermentation will provide theoretical basis for controlling of pathogenic microorganisms, and ensuring the safety of the fermented surimi product.

Abutilon theophrasti's defense against the allelochemical benzoxazolin-2(3H)-one: support by Actinomucor elegans.

Abutilon theophrasti Medik., previously found to be rather insensitive to benzoxazinoid containing rye mulch and the allelochemical benzoxazolin-2(3H)-one (BOA), can be associated with the zygomycete Actinomucor elegans, whereby the fungus colonizes the root relatively superficially and mainly in the maturation zone. The fungus mitigates necrosis of the cotyledons when seedlings are incubated with 2 mM BOA, in contrast to those that lack the fungus. In liquid cultures of the fungus, tryptophan was identified. The accumulation of tryptophan is increased in presence of BOA. This amino acid seems to be important in protecting Abutilon against BOA and its derivatives since it suppressed the accumulation of BOA derived, highly toxic 2-aminophen-oxazin-3-one (APO) in the medium and on the root surface during BOA incubations of Abutilon seedlings. Although A. elegans is insensitive to BOA and APO, the fungus is not able to protect the plant against harmful effects of APO, when seedlings are treated with the compound. Abutilon can detoxify BOA via BOA-6-OH glucosylation probably by a cell wall associated glucosyltransferase, but only low amounts of the product accumulate. Low tryptophan concentrations can contribute to a degradation of the toxic intermediate BOA-6-OH by Fenton reactions, whereby the amino acid is oxidized. One of the oxidation products was identified as 4(1H)-quinolinone, which is the core substructure of the quorum sensing molecule 2-heptyl-3-hydroxy-4-quinolone. The mutualistic association of Abutilon theophrasti with Actinomucor elegans is considered as opportunistic and facultative. Such plant-fungus associations depend rather likely on environmental conditions, such as the mode of fertilization.

Enhanced Glucosamine Production with Actinomucor elegans Based on Stimulating Factor of Methanol.

Glucosamine (GlcN) is a major and valuable component in the cell wall of fungi. In this study, the cell wall was treated via a two-stage alkali and acid process, and chitin and chitosan were fully deacetylated, partially depolymerized, and converted to GlcN oligosaccharides. Then, the oligosaccharides were analyzed by high performance liquid chromatography. The influences of Actinomucor elegans on GlcN production in a flask culture were investigated to achieve an optimum yield of GlcN. The experimental result showed that cultivation in condition of pH 6.0, 100mL working volume (500mL flask), 10% (v/v) inoculum concentration, at 28°C and 200rpm for 6days yielded highest dry cell weight (DCW) which was 23.43gL(-1), with a GlcN concentration of 5.12gL(-1). Methanol as stimulating factor was found to exert the best effect in concentration of 1.5% (v/v). With addition of methanol into medium, the DCW increased from 23.69 to 32.42g L(-1), leading to maximum GlcN concentration of 6.85gL(-1) obtained. Here, the methanol addition may be useful for industrial production of GlcN, and may also be meaningful for the production of other fine chemicals by filamentous fungi.

Biotransformation of resibufogenin by Actinomucor elegans

Resibufogenin (RB), a major bioactive bufadienolide, has the potential anticancer activity. In the present work, biotransformation of RB by Actinomucor elegans AS 3.2778 yielded five products, namely 3-oxo-resibufogenin (1), 3-epi-resibufogenin (2), 3-epi-12-oxo-hydroxylresibufogenin (3), 3α-acetoxy-15α-hydroxylbufalin (4), and 3-epi-12α-hydroxylresibufogenin (5), respectively. Among them, metabolites 3 and 4 are previously unreported. The chemical structures of metabolites 1–5 were fully elucidated on the basis of 2D NMR and HR-MS. The highly stereo- and regio-specific isomerization, hydroxylation, and esterification reactions were observed in the biotransformation process of RB by A. elegans. Their cytotoxicities against A549 and H1299 cells were evaluated.

Physical, chemical and microbiological characteristics of fermented surimi with Actinomucor elegans

The physical, chemical and microbiological changes of surimi during surimi pehtze preparation stage, with Actinomucor elegans XH-22 (A. elegans XH-22) as fermentation starter, were investigated. Enzyme assay showed that A. elegans XH-22 could continuously produce protease and α-amylase on surimi surface. Texture profile analysis (TPA) indicated that fermentation for 48 h decreased pH and moisture content and modified the texture properties of surimi. Increases in amino nitrogen and trichloroacetic acid-soluble nitrogen (TCA-N) contents revealed obvious surimi protein degradation, which was further confirmed by size-exclusion HPLC analysis of surimi water soluble protein. Fermentation significantly increased the content of free amino acids and enriched special amino acids such as histidine, phenylalanine and glutamic acid, which could influence the nutritional and sensory properties of fermented surimi product. Considerable levels of aerobic plate count, spores and LAB were detected during the fermentation process. It is thus, from a public health point of view, advisable that the fermentation time in the first stage be controlled to be within 36 h. This research gives a new clue for improving the utilization of low-value fish.

Biotransformation of resibufogenin by Actinomucor elegans and the cytotoxicity of the resulting metabolites

The microbial transformation of resibufogenin by cell suspension cultures of Actinomucor elegans AS 3.2778 yielded metabolites 1–6. The chemical structures of these transformed products were determined by various spectroscopic analyses, including 1D and 2D NMR and HRESIMS. Metabolites 3–5 were new compounds. Furthermore, metabolites 1, 5 and 6 showed moderate cytotoxicities against two human cancer cell lines (A549 and H1299) in an in vitro bioassay.

Biochemical, textural and microstructural changes in whole‐soya bean cotyledon sufu during fermentation

SummaryThis study aims to investigate the nutritional value of sufu and reduce environmental problems caused by okara, which results from the traditional processing method of sufu. The feasibility of the whole‐soya bean cotyledon sufu (WSCS) processing method, which does not produce okara, was investigated. WSCS was prepared by ripening okara‐containing tofu through various hydrolytic enzymes secreted by Actinomucor elegans for 70 days. After fermentation, total nitrogen, amino nitrogen and lipid contents were found to be lower in WSCS than in traditional sufu (TS), whereas contents of reducing sugar, dietary fibre, isoflavone aglycone and soya bean polysaccharide were higher in WSCS than in TS. The hardness, springiness and adhesiveness of WSCS were 249.703 ± 0.500 g, 0.606 ± 0.008 and 8.393 ± 0.032 J, respectively. The corresponding values for TS were 264.863 ± 0.572 g, 0.615 ± 0.007 and 7.516 ± 0.031 J, respectively. In addition, microstructural changes in WSCS and TS during fermentation were observed through scanning electron microscopy. The results from this study may provide a basis for industrial production of WSCS.

N2O emission from cropland field soil through fungal denitrification after surface applications of organic fertilizer

Agricultural fields are one of the largest anthropogenic sources of atmospheric nitrous oxide (N2O). Fungi have been suggested to contribute substantially to N2O emission in terrestrial environments; however, the extent of the fungal contribution and the phylogenetic and physiologic nature of related fungal communities in agricultural fields are largely unknown. This study focused on the large N2O emission from cropland soil that occurs after granular organic fertilizers were applied to the surface. The granular organic fertilizers applied were evidently covered by fungal mycelia. An experiment using a soil microcosm was established to imitate the field observations. N2O emissions following surface organic fertilization were suppressed by 84 and 20% after the addition of cycloheximide (a fungal inhibitor) and streptomycin (a bacterial inhibitor), respectively, suggesting that fungi provide the main contribution to the observed N2O emission. The population density and community composition of fungi in the surface-fertilized and non-fertilized soils in the field were determined using colony counting, denaturing gradient gel electrophoresis and subsequent phylogenetic analyses. Thirty-four fungal strains were isolated from the soils, and their N2O producing activities were analyzed. Fungal population density in the surface-fertilized soil (2.6 × 106 CFU/g) was much higher than that in the non-fertilized soil (1.0 × 105 CFU/g). In addition, the fungal community compositions of the soils differed. Actinomucor elegans, Bionectria ochroleuca, Fusarium avenaceum, Fusarium equiseti, Fusarium oxysporum, Fusarium solani and Nectria sp. dominated the surface-fertilized soil, and their activity in producing N2O was confirmed. These results suggested that N2O emission after the surface application of granular organic fertilizers in the cropland field mainly resulted from fungal denitrification.

Erratum to: Actinomucor elegans var. kuwaitiensis isolated from the wound of a diabetic patient

Erratum to: Actinomucor elegans var. kuwaitiensis isolated from the wound of a diabetic patient

Biosynthesis of gamma‐linolenic acid and beta‐carotene by Zygomycetes fungi

Due to increasing demand for natural sources of both polyunsaturated fatty acids (PUFAs) and beta-carotene, 28 Zygomycetes fungal soil isolates were screened for their potential to synthesize these biologically active compounds. Although all fungi produced C18 PUFAs, only nine strains also formed beta-carotene. Although Actinomucor elegans CCF 3218 was the best producer of gamma-linolenic acid (GLA) (251 mg/L), Umbelopsis isabellina CCF 2412 was found to be the most valuable fungus because of the dual production of GLA (217 mg/L) and beta-carotene (40.7 mg/L). The calculated ratio of formed PUFAs provided new insight into activities of individual fatty acid desaturases involved in biosynthetic pathways for various types of PUFAs. The maximal activity of delta-9 desaturase was accompanied by high accumulation of storage lipids in fungal cells. On the other hand, maximal activity of delta-15 desaturase was found in strains synthesizing low amounts of oleic acid due to diminished delta-9 desaturase. Activities of delta-6 desaturase showed competition for fatty acids engaged in n3, n6, and n9 biosynthetic pathways. Such knowledge about fatty acid desaturase activities provides new challenges for the regulation of biotechnological production of PUFAs by Zygomycetes fungi.

A Two‐Stage Process for the Production of a Novel Cheese Flavor Powder

AbstractA novel method to produce cheese flavor powder by combination mold fermentation and enzyme acceleration was developed. In this research, Actinomucor elegans was selected to ferment the milk. The optimum conditions for fermentation were 220 rpm, at the temperature 29C and for 2 days. In order to accelerate the flavor formation, the effects of lipase and protease to fermented milk were also investigated. According to the sensory evaluation scores, as well as the degree of hydrolysis, the optimum formula of enzymes were Palatase 2000 L 2‰ (m/v) and proteases 1‰ (m/v), proteases was prepared by mixing 2:1 (m/m) proportion of Flavourzyme 500MG and Neutrase 1.5MG. The optimum conditions for enzymolysis were 50C, 6.5 (initial pH) and 6 h (enzymolysis time), and the product of optimum process was tested by gas chromatography–mass spectrometry (GC‐MS). According to the sensory evaluation result and GC‐MS, the novel cheese flavor powder showed superior profile for its intensity and flavorful.Practical ApplicationCheese production has been considered as an important raw material of some food because of its great aroma and flavor. The novel cheese flavor powder is a product retaining the strong aroma and flavor of cheese, namely, creamy, odor, sour and pungent. The cheese flavor powder is mainly used as a spice in culinary preparations for imparting a characteristic cheese flavor. The product is generally light yellow in color and is stable in quality because of mealy structure and low moisture content. It is a ready‐to‐use preparation, which can be used in homes, restaurants and institutional catering. The development of novel cheese flavor powder with richer flavor, lighter weight and ease of use may be governed by a mass of customer favorite.

Production of Hydrolysates by Actinomucor elegans During Soy Protein Deep-liquid Fermentation

Production of Hydrolysates by Actinomucor elegans During Soy Protein Deep-liquid Fermentation