Metabolic engineering of Mucor circinelloides to improve astaxanthin production.

Astaxanthin is a bioactive natural pigment with antioxidant properties. It has extensive applications within the industrial sector as well as in human and animal health. Mucor circinelloides is a zygomycete fungus that accumulates ß-carotene as the main carotenoid compound. M. circinelloides is a well-known model organism among Mucorales for studying carotenogenesis in fungi, which makes it a promising candidate for the biotechnological production of carotenoids. In this study, ß-carotene hydroxylase (crtR-B) and ketolase (bkt) genes (codon-optimized) were coexpressed from Haematococcus pluvialis in M. circinelloides using two potent promoters gpd1 and zrt1 respectively to generate an astaxanthin-producing biofactory. Following 72 h of cultivation, the recombinant M. circinelloides Mc-57 obtained in this study produced 135 ± 8 µg/g of astaxanthin. This is the highest reported amount in M. circinelloides to date. The mRNA levels of crtR-B and bkt in Mc-57 were assayed using RT-qPCR. These levels showed a 5.7-fold increase at 72 h and a 5.5-fold increase at 24 h, respectively, compared to the control strain. This demonstrated the successful overexpression of both genes, which correlated with the production of astaxanthin in the Mc-57. Moreover, the addition of glutamate (2 g/L) and mevalonate (15 mM) resulted in an increase in astaxanthin production in the recombinant strain. The results showed that the combined addition of these metabolic precursors resulted in 281 ± 20 µg/g of astaxanthin, which is 2.08-fold higher than the control medium (135 ± 8 µg/g). The addition of metabolic precursors also positively impacted the biomass growth of Mc-57, reaching 11.2 ± 0.57 g/L compared to 9.1 ± 0.23 g/L (control medium). The study successfully addressed the challenge of balancing the accumulation of astaxanthin with biomass growth, which has been regarded as common bottleneck in the metabolic engineering of microbial cells. The development of a recombinant fungal strain of M. circinelloides not only increased astaxanthin content. Additionally, it provided a foundation for further improvement of the biotechnological production of astaxanthin in M. circinelloides.

Mechanistic analysis of thermal stability in a novel thermophilic polygalacturonase MlPG28B derived from the marine fungus Mucor lusitanicus.

In this study, heterologous MlPG28B expression was obtained by cloning the Mucor lusitanicus gene screened from a marine environment. The enzyme activity of MlPG28B was maximum at 60 °C, 30 % of the enzyme activity was retained after incubation at 100 °C for 30 min, and enzyme activity was still present after 60 min incubation, one of the best thermostable polygalacturonases characterized until now. The high-purity oligosaccharide standards (DP2-DP7) were prepared with polygalacturonic acid as a substrate. Kinetic parameters showed that MlPG28B at the optimum temperature has a low Km value (3055 ± 1104 mg/L), indicating high substrate affinity. Sequence alignment analysis inferred key residues Cys276, Cys284, Lys107, and Gln237 for MlPG28B thermal stability. Molecular docking and molecular dynamics simulation results indicated that MlPG28B has flexible T1 and T3 loops conducive to substrate recognition, binding, and catalysis and forms a hydrogen bond to the substrate by a highly conserved residue Asn161 in the active-site cleft. Based on site-directed mutation results, the five residues are key in determining MlPG28B thermal stability. Therefore, MlPG28B is a promising candidate for industrial enzymes in feed preparation.

Production and biochemical and biophysical characterization of fibrinolytic protease of a Mucor subtilissimus strain isolated from the caatinga biome.

Cardiovascular diseases, resulting from the deposition of clots in blood vessels, are the leading cause of death worldwide. Fibrinolytic enzymatic activity can catalyze blood clot degradation. Findings show that 36 fungal isolates recovered from Caatinga soils have the potential to produce fibrinolytic protease under submerged conditions. About 58 % of the isolates displayed fibrinolytic activity above 100 U/mL, with Mucor subtilissimus UCP 1262 being the most active. The protease was biochemically and biophysically characterized, showing that the enzyme had a high affinity for SAApNA substrate and was significantly inhibited by fluoride methyl phenyl sulfonyl-C7H7FO2S, suggesting that it is a chymotrypsin-like serine protease. The highest enzyme activity was detected at pH 5.0 and 28 °C. This fibrinolytic protease's far-UV circular dichroism (CD) showed that its secondary structure was primarily α-helical. The purified fibrinolytic enzyme may represent a novel therapeutic agent for treating thrombosis. At temperatures above 65 °C, the enzyme lost all its secondary structure. Its melting temperature was 58.1 °C, the denaturation enthalpy 85.1 kcal/mol, and the denaturation entropy 0.26 kcal/K∙mol.

Successful treatment of mixed pulmonary Aspergillus and Mucor infection using intrabronchial amphotericin B infusion: a case report and literature review.

BACKGROUND: Reports of pulmonary aspergillosis and mucormycosis co-infections are rare; thus, limited guidance is available on early diagnosis and treatment. We present a case of mixed pulmonary Aspergillus and Mucor infection and review the literature regarding this co-infection. The diagnosis and treatment methods are summarized to improve clinicians' understanding of the disease and to facilitate early diagnosis and treatment. CASE PRESENTATION: A 60-year-old male farmer with poorly controlled diabetes mellitus was admitted to hospital with a fever of unknown origin that had been present for 15 days and pulmonary aspergillosis complicated by Mucor spp. INFECTION: Because multiple lobes were involved, the infection worsened despite surgical resection and antifungal therapy. Finally, we treated this patient with a bronchoscopic infusion of amphotericin B. After four courses of bronchoscopic amphotericin B infusion, we observed rapid clinical improvement and subsequent resolution of pulmonary infiltrates. CONCLUSION: Our case highlights the use of bronchoscopy in the successful clinical treatment of invasive fungal diseases of the lung.

Continuous production of chitooligosaccharides in a column reactor by the PUF-immobilized whole cell enzymes of Mucor circinelloides IBT-83.

BACKGROUND: Chitosan oligosaccharides (COS) have great potential for applications in several fields, including agriculture, food industry or medicine. Nevertheless, the large-scale use of COS requires the development of cost-effective technologies for their production. The main objective of our investigation was to develop an effective method of enzymatic degradation of chitosan in a column reactor using Mucor circinelloides IBT-83 cells, immobilized in a polyurethane foam (PUF). These cells serve as a source of chitosanolytic enzymes. RESULTS: The study revealed that the process of freeze-drying of immobilized mycelium increases the stability of the associated enzymes during chitosan hydrolysis. The use of stabilized preparations as an active reactor bed enables the production of COS at a constant level for 16 reactor cycles (384 h in total), i.e. 216 h longer compared to non-stabilized mycelium. In the hydrolysate, oligomers ranging in structure from dimer to hexamer as well as D-glucosamine were detected. The potential application of the obtained product in agriculture has been verified. The results of phytotests have demonstrated that the introduction of COS into the soil at a concentration of 0.01 or 0.05% w/w resulted in an increase in the growth of Lepidium sativum stem and root, respectively (extensions by 38 and 44% compared to the control sample). CONCLUSIONS: The research has verified that the PUF-immobilized M. circinelloides IBT-83 mycelium, which has been stabilized through freeze-drying, is a promising biocatalyst for the environmentally friendly and efficient generation of COS. This biocatalyst has the potential to be used in fertilizers.

Molecular architecture of chitin and chitosan-dominated cell walls in zygomycetous fungal pathogens by solid-state NMR.

Zygomycetous fungal infections pose an emerging medical threat among individuals with compromised immunity and metabolic abnormalities. Our pathophysiological understanding of these infections, particularly the role of fungal cell walls in growth and immune response, remains limited. Here we conducted multidimensional solid-state NMR analysis to examine cell walls in five Mucorales species, including key mucormycosis causative agents like Rhizopus and Mucor species. We show that the rigid core of the cell wall primarily comprises highly polymorphic chitin and chitosan, with minimal quantities of ß-glucans linked to a specific chitin subtype. Chitosan emerges as a pivotal molecule preserving hydration and dynamics. Some proteins are entrapped within this semi-crystalline chitin/chitosan layer, stabilized by the sidechains of hydrophobic amino acid residues, and situated distantly from ß-glucans. The mobile domain contains galactan- and mannan-based polysaccharides, along with polymeric α-fucoses. Treatment with the chitin synthase inhibitor nikkomycin removes the ß-glucan-chitin/chitosan complex, leaving the other chitin and chitosan allomorphs untouched while simultaneously thickening and rigidifying the cell wall. These findings shed light on the organization of Mucorales cell walls and emphasize the necessity for a deeper understanding of the diverse families of chitin synthases and deacetylases as potential targets for novel antifungal therapies.

Lipid production from corn straw by cellobiohydrolase and delta-6 desaturase engineered Mucor circinelloides strains under solid state fermentation.

Previously, we constructed engineered M. circinelloides strains that can not only utilize cellulose, but also increase the yield of γ-linolenic acid (GLA). In the present study, an in-depth analysis of lipid accumulation by engineered M. circinelloides strains using corn straw was to be explored. When a two-stage temperature control strategy was adopted with adding 1.5% cellulase and 15% inoculum, the engineered strains led to increases in the lipid yield (up to 1.56 g per 100 g dry medium) and GLA yield (up to 274 mg per 100 g dry medium) of 1.8- and 2.3-fold, respectively, compared with the control strain. This study proved the engineered M. circinelloides strains, especially for Mc-C2PD6, possess advantages in using corn straw to produce GLA. This work provided a reference for transformation from agricultural cellulosic waste to functional lipid in one step, which might play a positive role in promoting the sustainable development of biological industry.

Simultaneous aerobic nitrogen and phosphorus removal by novel halotolerant fungus Mucor circinelloides SNDM1: Function and metabolism pathway.

Fungi capable of simultaneous nitrogen and phosphorus removal from wastewater is rarely found. Here, a novel fungal strain (SNDM1) performing heterotrophic nitrification, aerobic denitrification, and phosphate removal was isolated and identified as Mucor circinelloides. The favorable nutrient removal conditions by the strain using glucose were C/N ratios of 25-30, salinities of 0 %-3 %, and pH of 7.5. Strain SNDM1 achieved ammonium, nitrite, nitrate, and phosphate removal rates of 5.23, 10.08, 4.88, and 0.97 mg/L/h. Nitrogen balance indicated that gaseous (18.60 %-24.55 %) and intracellular nitrogen (43.76 %-70.63 %) were primary fate of initial nitrogen. Enzyme activity revealed that ammonium removal occurred through heterotrophic nitrification and aerobic denitrification. Removed phosphorus was mainly transformed into cell membranes (56 %-64 %) and extracellular polymeric substances (20 %-26 %). Orthophosphate was the major intracellular phosphorus species, while polyphosphate and pyrophosphate existed extracellularly. These findings highlight the potential of this fungal strain for bioremediating polluted wastewater.

A one-pot five component reaction for the synthesis of tetrazol-benzofuran hybrids and their inhibitory activity against Mucor lusitanicus.

A synthetic strategy for obtaining a new series of 1,5-disubstituted tetrazole-benzofuran hybrid systems via a one-pot five-component reaction is described. This process involves a Ugi-azide multicomponent reaction coupled to an intramolecular cyclization catalyzed by Pd/Cu, resulting in low to moderate yields from 21 to 67%. This protocol allowed the synthesis of highly substituted benzofurans at the 2-position through an operationally simple process under mild reaction conditions and with high bond forming efficiency due to the formation of six new bonds (two C-C, two C-N, one N-N, and one C-O). Besides, to evaluate the antifungal activity of 1,5-disubstituted tetrazole-benzofurans 9a-n, in vitro studies against Mucor lusitanicus were performed, finding that compound 9b exhibits bioactivity comparable to the commercial antifungal drug Amphotericin B. These results suggest potential for use in controlling mucormycosis infections in animal models, highlighting the importance of these findings given the limited antifungal drug options and high mortality rates associated with this infection.

Functional characterization of two survival factor 1 genes in Mucor lusitanicus.

Survival factor 1 (Svf1) protein has been described in some ascomycetous fungi where it was found to be contributing to several essential physiological processes, such as response to osmotic, oxidative and cold stresses, sphingolipid biosynthesis, morphogenesis, sporulation, antifungal resistance, and pathogenicity. It was also suggested that it can be a novel central regulator affecting the expression of various genes. In the present study, function of this protein and the encoding genes is described for the first time in a fungus (i.e., in Mucor lusitanicus) belonging to the order Mucorales. M. lusitanicus has two putative svf1 genes named svf1a and svf1b. Expression of both genes was proven. Although the expression of svf1a was affected by several environmental stresses and knocking out the gene affected adaptation to low temperatures and the sporulation ability, the main survival factor functions, such as participation in the maintenance of the viability, the response to oxidative and cold stresses, and the sphingolipid biosynthesis, could be associated with Svf1b, suggesting a central regulatory role to this protein. Interestingly, knockout of both genes affected the pathogenicity of the fungus in a Drosophila model. IMPORTANCE: Mucor lusitanicus is a widely used model organism to study various biological processes in the basal fungal group Mucorales. Several members of this group can be agents of mucormycosis, an opportunistic fungal infection, which is associated with high mortality, rapid progression, and wide resistance to the commonly used antifungal agents. Svf1 proteins have so far only been identified in fungi, where they have been involved in pathogenicity and resistance to antifungal agents in many cases. Only a limited number of factors affecting the stress response, antifungal resistance, and virulence of Mucorales fungi have been revealed. Elucidating the function of a fungus-specific protein that may regulate these processes may bring us closer to understanding the pathogenesis of these fungi.

Myo5B plays a significant role in the hyphal growth and virulence of the human pathogenic fungus Mucor lusitanicus.

Mucormycosis is an emerging and deadly invasive fungal infection caused by fungi belonging to the Mucorales order. We investigated the myosin superfamily, which encompasses diverse actin-based motor proteins with various cellular functions. Specifically, the role of the Myo5B (ID 179665) protein from the myosin class V family in Mucor lusitanicus was explored by generating silencing phenotypes and null mutants corresponding to the myo5B gene. Silencing fungal transformants exhibited a markedly reduced growth rate and a nearly complete absence of sporulation compared to the wild-type strain. The myo5BΔ null mutant strain displayed atypical characteristics, including abnormally short septa and inflated hyphae. Notably, there were a majority of small yeast-like cells instead of filamentous hyphae in the mutant. These yeast-like cells cannot germinate normally, resulting in a loss of polarity. In vivo virulence assays conducted in the Galleria mellonella invertebrate model revealed that the myo5BΔ mutant strain was avirulent. These findings shed light on the crucial contributions of the Myo5B protein to the dimorphism and pathogenicity of M. lusitanicus. Therefore, the myosin V family is a potential target for future therapeutic interventions aimed at treating mucormycosis.

Regulation of AreA on lipid biosynthesis under different nitrogen sources and C/N ratios in the model oleaginous fungus Mucor circinelloides.

Mucor circinelloides has been exploited as model filamentous fungi for studies of genetic manipulation of lipogenesis. It is widely recognized that lipid accumulation is increased when there is a lack of nitrogen source in oleaginous microorganism. Nitrogen metabolism in filamentous fungi is a complex process that can be regulated by the global nitrogen regulator AreA. In this study, we cultivated the areA-knockout and -overexpression strains obtained in our previous study, using 20 different nitrogen sources. It emerged that the disruption of AreA in M. circinelloides reduced its sensitivity to nitrogen availability, resulting in increased lipid synthesis. Specially, the areA-knockout strain was unable to fully utilize many nitrogen sources but the ammonium and glutamate. We continued to investigate lipid production at different molar C/N ratios using glucose as sole carbon source and ammonium sulfate as sole nitrogen source, of which the high C/N ratios activate high lipid accumulation. By comparing the experimental results with transcriptional analysis, we were able to identify the optimal process conditions suitable for lipid accumulation and potential targets for future metabolic engineering.

Alternative ergosterol biosynthetic pathways confer antifungal drug resistance in the human pathogens within the Mucor species complex.

Mucormycoses are emerging fungal infections caused by a variety of heterogeneous species within the Mucorales order. Among the Mucor species complex, Mucor circinelloides is the most frequently isolated pathogen in mucormycosis patients and despite its clinical significance, there is an absence of established genome manipulation techniques to conduct molecular pathogenesis studies. In this study, we generated a spontaneous uracil auxotrophic strain and developed a genetic transformation procedure to analyze molecular mechanisms conferring antifungal drug resistance. With this new model, phenotypic analyses of gene deletion mutants were conducted to define Erg3 and Erg6a as key biosynthetic enzymes in the M. circinelloides ergosterol pathway. Erg3 is a C-5 sterol desaturase involved in growth, sporulation, virulence, and azole susceptibility. In other fungal pathogens, erg3 mutations confer azole resistance because Erg3 catalyzes the production of a toxic diol upon azole exposure. Surprisingly, M. circinelloides produces only trace amounts of this toxic diol and yet, it is still susceptible to posaconazole and isavuconazole due to alterations in membrane sterol composition. These alterations are severely aggravated by erg3Δ mutations, resulting in ergosterol depletion and, consequently, hypersusceptibility to azoles. We also identified Erg6a as the main C-24 sterol methyltransferase, whose activity may be partially rescued by the paralogs Erg6b and Erg6c. Loss of Erg6a function diverts ergosterol synthesis to the production of cholesta-type sterols, resulting in resistance to amphotericin B. Our findings suggest that mutations or epimutations causing loss of Erg6 function may arise during human infections, resulting in antifungal drug resistance to first-line treatments against mucormycosis. IMPORTANCE: The Mucor species complex comprises a variety of opportunistic pathogens known to cause mucormycosis, a potentially lethal fungal infection with limited therapeutic options. The only effective first-line treatments against mucormycosis consist of liposomal formulations of amphotericin B and the triazoles posaconazole and isavuconazole, all of which target components within the ergosterol biosynthetic pathway. This study uncovered M. circinelloides Erg3 and Erg6a as key enzymes to produce ergosterol, a vital constituent of fungal membranes. Absence of any of those enzymes leads to decreased ergosterol and consequently, resistance to ergosterol-binding polyenes such as amphotericin B. Particularly, losing Erg6a function poses a higher threat as the ergosterol pathway is channeled into alternative sterols similar to cholesterol, which maintain membrane permeability. As a result, erg6a mutants survive within the host and disseminate the infection, indicating that Erg6a deficiency may arise during human infections and confer resistance to the most effective treatment against mucormycoses.

Preparation of Pinoresinol and Dehydrodiconiferyl Alcohol from Eucommiae Cortex Extract by Fermentation with Traditional Mucor.

Eucommiae Cortex (EC) is frequently used alone or in combination with other active ingredients to treat a range of illnesses. An efficient technical instrument for changing cheap or plentiful organic chemicals into rare or costly counterparts is biotransformation. It combines EC with biotransformation techniques with the aim of producing some novel active ingredients, using different strains of bacteria that were introduced to biotransform EC in an aseptic environment. The high-quality strains were screened for identification after the fermentation broth was found using HPLC, and the primary unidentified chemicals were separated and purified in order to be structurally identified. Strain 1 was identified as Aspergillus niger and strain 2 as Actinomucor elegans; the main transformation product A was identified as pinoresinol (Pin) and B as dehydrodiconiferyl alcohol (DA). The biotransformation of EC utilizing Aspergillus niger and Actinomucor elegans is reported for the first time in this study's conclusion, resulting in the production of Pin and DA.

Mucor germinans, a novel dimorphic species resembling Paracoccidioides in a clinical sample: questions on ecological strategy.

Dimorphism is known among the etiologic agents of endemic mycoses as well as in filamentous Mucorales. Under appropriate thermal conditions, mononuclear yeast forms alternate with multi-nucleate hyphae. Here, we describe a dimorphic mucoralean fungus obtained from the sputum of a patient with Burkitt lymphoma and ongoing graft-versus-host reactions. The fungus is described as Mucor germinans sp. nov. Laboratory studies were performed to simulate temperature-dependent dimorphism, with two environmental strains Mucor circinelloides and Mucor kunryangriensis as controls. Both strains could be induced to form multinucleate arthrospores and subsequent yeast-like cells in vitro. Multilateral yeast cells emerge in all three Mucor species at elevated temperatures. This morphological transformation appears to occur at body temperature since the yeast-like cells were observed in the lungs of our immunocompromised patient. The microscopic appearance of the yeast-like cells in the clinical samples is easily confused with that of Paracoccidioides. The ecological role of yeast forms in Mucorales is discussed.IMPORTANCEMucormycosis is a devastating disease with high morbidity and mortality in susceptible patients. Accurate diagnosis is required for timely clinical management since antifungal susceptibility differs between species. Irregular hyphal elements are usually taken as the hallmark of mucormycosis, but here, we show that some species may also produce yeast-like cells, potentially being mistaken for Candida or Paracoccidioides. We demonstrate that the dimorphic transition is common in Mucor species and can be driven by many factors. The multi-nucleate yeast-like cells provide an effective parameter to distinguish mucoralean infections from similar yeast-like species in clinical samples.

Synergistic action of lactoferrin and its derived functional fragments as a promising therapeutic agent in combating mucormycosis.

Aim: Currently, we have limited armamentarium of antifungal agents against Mucorales. There is an urgent need to discover novel antifungal agents that are effective, safe and affordable. Materials & methods: In this study, the anti-Mucorale action of native lactoferrin (LF) and its functional fragments CLF, RR6 and LFcin against three common Mucorale species are reported. The synergistic action of LF with antifungal agents like amphotericin B, isavuconazole and posaconazole was analyzed using checkerboard technique. Results: All the three mucor species showed inhibition when treated with fragments. The checkerboard assay confirmed that native LF showed the best synergistic action against Mucorales in combination with Amphotericin B. Conclusion: These results highlight the potential therapeutic value of native LF against Mucorales.

Black fungus, or 'mucormycosis', is a dangerous fungal infection. Normally, it affects people with a weakened immune system. It is only treatable when diagnosed early. It spreads by breathing the fungus in, eating contaminated food or direct contact with an infected wound. There are not many medicines that can treat this type of fungus, so it is important to find new ones. In this study, we tested a natural protein called lactoferrin and some of its building blocks, called peptides, to see if they could stop the fungus from growing. Lactoferrin and its peptides could stop the fungus from growing, especially when used with a medicine called amphotericin B. This means that lactoferrin could potentially be a helpful treatment for this fungal infection.

Clinical Significance of Mucor in Airway Culture of Immunocompetent Patients With Chronic Lung Disease.

OBJECTIVES: Mucor within the airways of immunocompromised patients often signifies an invasive life-threatening infection. However, its significance in immunocompetent patients with chronic lung diseases is less clear. We aimed to assess the clinical implication of mucor in airway-secretion cultures of these patients. METHODS: A single-center retrospective cohort study was performed. Patients with cystic fibrosis (CF), primary ciliary dyskinesia (PCD) or non-CF/non-PCD bronchiectasis followed in our Pediatric Pulmonary Institute, with sputum or bronchoalveolar lavage cultures growing Mucorales molds in the years 2010-2022, were included. Demographic and clinical parameters such as body mass index and spirometry values (forced expiratory volume at 1 second) were collected and compared with values up to 12 months prior to and following the index (positive culture) visit. RESULTS: A total of 27 patients of whom 22 (82%) patients were with CF, 3 with PCD (11%) and 2 (7%) with non-CF/non-PCD bronchiectasis were included. Median age was 21.8 (14.9-32.1) years, with forced expiratory volume at 1 second of 62.8% ± 21.9% at the index visit. None of the patients developed disseminated disease, none had clinical or radiological evidence of fungal disease and none required antifungal therapy. Throughout the 12 months prior to and following the positive cultures, no significant changes were noted in body mass index, forced expiratory volume at 1 second, frequency of pulmonary exacerbations, days of hospitalization or days of antibiotic treatment. CONCLUSIONS: Evidence of mucor in airway cultures of immunocompetent patients with chronic lung disease does not necessarily signify clinical deterioration nor suggests invasive fungal disease. Larger, long-term prospective studies are required to obviate the need for a thorough evaluation in these patients.

Mucor thermorhizoides-A New Species from Post-mining Site in Sudety Mountains (Poland).

Mucor representatives are mostly rapidly growing cosmopolitan soil saprotrophs of early diverged Mucoromycotina subphylum. Although this is the most speciose genus within the group, some lineages are still understudied. In this study, new species of Mucor was isolated from the post-mining area in southwestern Poland, where soil chemical composition analysis revealed high concentration of hydrocarbons and heavy metals. Phylogenetic analysis based on multigene phylogeny showed that the new isolate clusters distinctly from other Mucor species as a sister group to Mucor microsporus. New species Mucor thermorhizoides Abramczyk (Mucorales, Mucoromycota) is characterized by the extensive rhizoid production in elevated temperatures and formation of two layers of sporangiophores. It also significantly differs from M. microsporus in the shape of spores and the size of sporangia. M. thermorhizoides was shown to be able to grow in oligotrophic conditions at low temperatures. Together with M. microsporus they represent understudied and highly variable lineage of the Mucor genus.

A new polyene macrolide antibiotic, machidamycin, produced by Streptomyces sp. K22-0017.

A new polyene macrolide, machidamycin (1), and a known compound YS-822A (2), were obtained by physicochemical screening from a culture broth of Streptomyces sp. K22-0017. The structures were elucidated using MS and 1D/2D NMR analyses. Compound 1 exhibited weak antifungal activity against Candida albicans and Mucor racemosus. Furthermore, 1 showed stronger antileishmanial activity than the existing drug paromomycin.

Assessing the efficacy of the ovicidal fungus Mucor circinelloides in reducing coccidia parasitism in peacocks.

The biological control of gastrointestinal (GI) parasites using predatory fungi has been recently proposed as an accurate and sustainable approach in birds. The current study aimed to assess for the first time the efficacy of using the native ovicidal fungus Mucor circinelloides (FMV-FR1) in reducing coccidia parasitism in peacocks. For this purpose, an in vivo trial was designed in the resident peacock collection (n = 58 birds) of the São Jorge Castle, at Lisbon, Portugal. These animals presented an initial severe infection by coccidia of the genus Eimeria (20106 ± 8034 oocysts per gram of feces, OPG), and thus received commercial feed enriched with a M. circinelloides suspension (1.01 × 108 spores/kg feed), thrice-weekly. Fresh feces were collected every 15 days to calculate the coccidia shedding, using the Mini-FLOTAC technique. The same bird flock served simultaneously as control (t0 days) and test groups (t15-t90 days). The average Eimeria sp. shedding in peacocks decreased up to 92% following fungal administrations, with significant reduction efficacies of 78% (p = 0.004) and 92% (p = 0.012) after 45 and 60 days, respectively. Results from this study suggest that the administration of M. circinelloides spores to birds is an accurate solution to reduce their coccidia parasitism.