Mycelial Filaments Research Articles

Favorable outcome of Lasiodiplodia theobromae keratomycosis : a clinical case and systematic review

BackroudKeratitis caused by Lasiodiplodia theobromae is rare and typically associated with a poor prognosis. Current literature lacks sufficient evidence on effective management of patients with this condition.Case presentationA 74-year-old former agricultural worker presented with a red right eye, discomfort, and decreased visual acuity, progressing over three days without treatment. Examination revealed type 2 diabetes and a non-perforating, spiculated corneal abscess with a hypopyon in the right eye. Initial treatment included a triple antibiotic therapy and supportive care. Direct mycological examination identified numerous septate mycelial filaments. Antifungal treatment with natamycin and voriconazole, both topically and orally, was initiated. Cultures confirmed Lasiodiplodia theobromae. The patient showed significant improvement. Treatment continued for eight weeks, with a final visual acuity of 20/50 due to a stromal scar.ConclusionAn extensive literature review conducted in November 2023, using databases such as PubMed and Google Scholar with the keywords “lasiodiplodia” and “keratitis” yielded no previous cases of this specific condition being managed solely with the combined use of natamycin and voriconazole. This antifungal combination is commonly included in most management protocols for fungal keratitis. Factors such as the use of corticosteroids and delayed diagnosis were noted to adversely affect the prognosis. This case and this systematic review underscores the potential for non-surgical management options in severe fungal keratitis.

Epidemiological and mycological profile of superficial mycoses in diabetic patient

Introduction: Superficial mycoses, especially those of nails, scalp and skin, are very common in various countries. The presence of specific terrain, as well as other factors, can affect the prevalence of these. In this sense, diabetic patients are more susceptible to infections especially fungal infections because of changes in the immune system and macro and microvascular changes. The objective of our study was to determine the epidemiological and mycological profile of superficial mycoses in diabetic patients at the Mohammed VI Hospital in Oujda (Morocco). Material and methods: This is a retrospective, observational and descriptive study spread over 34 months, from January 2021 to October 2023 at the Parasitology-Mycology laboratory of the Mohammed VI Hospital Center of Oujda. We collected demographic and mycological data for the included patients. In the laboratory, upon reception of the samples, a direct examination (DE) of the sample was obtained after clarification by KOH to better visualize the mycelial filaments or yeasts and culture on both media: Sabouraud with chloramphenicol and Sabouraud with chloramphenicol and cycloheximide is systematically carried out. Results: We collected 136 diabetic patients referred to our laboratory for suspicion of superficial mycosis. The latter was confirmed in 46 of the 136 diabetic patients (33.82%) referred to our laboratory, which corresponds to 50 lesions among the 166 sites taken, a prevalence of 30.12%. At the mycological examination, the DE allowed the confirmation of the diagnosis of mycoses in 64% (n=32) and showed most often mycelial filaments (n=21; 65.62%) especially at the level of the feet and yeasts were observed in particular at the level of the nails of the hands (n=11; 34.37%). While culture was positive in all cases without exception (100%; n=50), dermatophytes were the most frequently isolated fungi (n=30; 60%), followed by yeasts (n=20; 40%). By species, T. rubrum (n=30; 60%) was the only isolated dermatophyte species, followed by Candida albicans (n=17; 34%). Conclusion: In recent years, we have seen an increase in the prevalence of superficial mycoses in diabetic patients which is why we conducted this study. The results show on the one hand that the most isolated fungi in the superficial mycoses of these patients are dominated by dermatophytes, as T. rubrum represents the most frequently encountered species. Furthermore, the high prevalence of the latter demonstrates the significance of implementing important prevention measures.

The Potential of Mycofoam as a Biocomposite Material with Various Substrate and Mushroom Compositions

Mycofoam is a biocomposite composed of mycelial filaments that bind to the host substrate, which can replace polystyrene. This research aims to determine the most appropriate formulation of the growing medium and mushroom to be used in mycofoam products based on some parameters. Composition is one of the main factors for selecting the most appropriate mycofoam to replace polystyrene. On the other hand, the quality of mycofoam can be assessed through its strength and water resistance. The mushroom mycelium used in this study came from Pleurotus ostreatus and Lentinula edodes. Besides, the growing medium formulation comprises five different compositions, each containing different proportions of sawdust and bagasse. This research was composed of preparation of growing medium, spawn inoculation, molding, heating, testing, and data analysis. Based on the results, the combination of 100 percent sawdust and L. edodes was the most appropriate choice compared to other formulations based on strength and appearance. The results of the water absorption test showed that all mycofoam formulations were not resistant to water, bio-based coating can be used to overcome this problem.

Pubic Majocchi Granuloma in a 49-Years- Old Immunocompetent Woman Performing Skin Bleaching

Majocchi's granuloma is a deep dermal infection caused by dermatophytes. It has been described in the context of immunodepression secondary to infection with immunosuppressive treatment. It represents an important functional and aesthetic prejudice. The diagnosis is often late. We report a case located on the pubis in a 49-year-old immunocompetent patient in a context of voluntary depigmentation. The patient presented with onychomycosis and dermatophytes on the pubic area. The diagnosis was based on clinical findings and the presence of mycelial filaments on direct examination. The patient was treated with terbinafine with regression of the lesions in four weeks.

P163 Successful management of COVID-19-associated mucormycosis in state of pernambuco, northestearn brazil: 2 case reports

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PMObjectivesDuring the COVID-19 pandemic, several cases of mucormycosis related to SARS-CoV-2 were reported. This association is still poorly studied due to its recent emergence and makes diagnosis and treatment challenging. Usually, patients who are affected by this infection are immunocompromised by corticosteroid treatment and uncontrolled diabetes mellitus, being mucormycosis a life-threatening opportunistic invasive fungal infection caused by mucoromycetes, which reaches a mortality rate of about 50%, even with treatment. Thus, this association requires as much information as possible about the pathogenesis and treatment.MethodsHere, we report two cases with conclusive diagnosis and positive evolution to mucormycosis associated with COVID-19 after corticosteroid therapy.ResultsThe first case was a 68-year-old woman, hypertensive and diabetic, who was affected by SARS-CoV-2, with intense ocular pain and paralysis of extrinsic ocular muscles of the right eye and eyelid. The patient underwent CT scan of the sinuses with contrast, which showed signs on maxillary. The patient was submitted to sinusectomy with orbital decompression and the material from the surgery was sent for fungal investigation, which 20% KOH direct exam showed hyaline, sparsely-septate, broad, ribbon-like hyphae with irregular right-angle branching. Rhizopus oryzae was isolated on Sabouraud agar. Mucormycosis was diagnosed in the facial sinuses, and resolution of infection was obtained with liposomal amphotericin B. The second case was a 59-year-old woman, obesity degree 3, asthmatic and history of COVID-19, with history of abscesses in oral mucosa and palate, with drainage of brown secretion after 30 days of COVID-19 resolution. After medical discharge, the patient was evaluated by an oral and maxillofacial surgeon to solve an esthetic problem, when the material was collected for biopsy of the mucosal lesions. Histopathological exam showed aseptic thick mycelial filaments presenting right angle bifurcation, suggestive of Mucorales (mucormycosis). The patient was readmitted to the hospital for mucormycosis treatment based on isavuconazole (200 mg, q8 as attack dose on Day 1 and 2, and 3 toward q24), and treatment evolved positively with no need for surgical intervention. We conclude that the extensive use of steroids associated with diabetes is the main factor for the appearance of mucormycosis after COVID-19, but with a conclusive diagnosis and correct treatment, this infection can have a good evolution, resulting in an improvement in the patient's clinical condition, reducing the risk of death for this infection.ConclusionIsavuconazole appears to be a drug with a safe profile and with curative potential for mucormycosis. The possibility of oral use from the third day at its maintenance dose (200 mg/day) with intravenous use in the first 48 h at a dose of 200 mg every 8 h. Diabetic patients are more prone to infection, but patients infected with SARS CoV 2 using corticosteroids have shown to be a risk group for this fungus.

Le signe du halo et l’aspergillose pulmonaire angio-invasive

We here report the case of a 52-year-old man, admitted to the emergency room with fever, persistent cough and hemoptysis evolving over a month. The patient reported no past medical history or specific treatment. There was no evidence of tuberculosis infection. He had consulted a month before with the same symptoms. Chest X-ray had showed right upper lobe pneumonia. The search for tubercular bacilli in sputum was negative. Probabilistic antibiotic treatment was started without success. At the time of admission, febricle not exceeding 38°C and respiratory rate 38 breaths/minute were reported. Crackling sounds in right upper lobe of the lung were heard. Laboratory tests showed neutropenia 410/µl and inflammatory syndrome with CRP levels 112.4 mg/l. VIH serology was negative. Given the persistence of symptoms despite antibiotic treatment, chest CT scan was performed, which showed right apical hyperdense nodule measuring 18x21 mm surrounded by a hyperdense ground glass area, producing a halo sign. No hilar or mediastinal adenomegaly was reported. Left lung was normal. Analysis in the bronchoalveolar lavage fluid (LBA) performed 3 days later showed the presence of septate mycelial filaments on direct examination. The diagnosis of angio-invasive pulmonary aspergillosis was based on these findings. Patient’s outcome was unfavorable, following the appearance of hemoptysis of great abundance and respiratory distress. The patient died 12 hours after bronchoalveolar lavage (BAL).

Vaginal ecology in Cameroonian urban areas: study of the flora of douala city inhabitants

Introduction: The vaginal flora consists of bacilli of Doderleïn (various species of lactobacilli) which constitute a biofilm on the mucosa. These bacteria play a protective role by inhibiting the growth, adhesion or expansion of other microorganisms. To do this, various mechanisms are deployed, including the secretion of organic acids, antimicrobial substances, competition for nutrients and receptor sites as well as steric exclusion. This balance is sometimes called into question by the use of oral medications and antiseptics for vaginal cleansing, oral contraception, diseases such as the Human Immunodeficiency Virus (HIV) or diabetes. Objective: The objective of this work was to study the vaginal flora of women residing in the city of Douala. Methodology: we carried out in three health structures in the city of Douala a transverse analytical study for seven (7) months in women aged at least 21 years. We randomly included 540 women who gave their written and signed consent. The variables of interest were socio-demographic, clinical and microbiological variables. Gram staining was used and read using an optical microscope for the identification of microorganisms and the classification of flora consisting of bacteria from vaginal secretions. The statistical tests used for the comparison of the numbers were chi-square and the exact fisher test with a significance threshold of 5% (p<0.05) Results: A total of five hundred and forty (540) women had their samples collected. The majority age group was that of 30-40 years with 28.30% of cases. The mean age was 42.58 years (+/- 13.37). Four types of vaginal flora have been identified, in particular Type 4 (complete disappearance of the Döderlein flora with the appearance of abundant, polymorphic replacement flora and presence of clues-cells) with 36.30% of cases; Type 3 (rare, minority lacto-bacillary flora with the appearance of a substitution flora with a dominant morphology) at 32.20%; Type 1 (mainly Döderlein flora: lactobacilli) at 17.20%; Type 2 (Döderlein flora present and predominant but with a substitution flora without dominant morphology) at 14.30%. The factors associated with the flora imbalance were scented soaps (OR=1.84; 95% CI=1.77-2.73; P=0.001), antiseptic products (OR=2.04; 95% CI=1, 05-5.67; P=0.004) and the risk increased by combining them (OR=4.04; 95% CI=3.92-6.49; P=0.001) 95% CI=1.77-2.73; P=0.001), Oral contraception, HIV infection and diabetes also altered the flora. In addition, the presence of yeasts and mycelial filaments also favoured the degradation of the flora. On the other hand, drinking water appeared as a protective factor (OR=0.19; 95% CI=0.043-0.84; P=0.028). Conclusion: the vaginal flora of women residing in Douala is mainly degraded in a cumulative percentage of 68.50% and represented by types 4 and 3.

Phoma macrostoma сирек кездесетін онихомикоз қоздырғышының сипаттамасы (син. Didymella macrostoma)

The article presents the results of studying the biological properties of the Phoma macrostomastrain, first described in Kazakhstan as the causative agent of onychomycosis. The authors obtained a pure culture of Phoma macrostoma coelomic, isolated from the affected nail plate of a patient in a narcological dispensary, and studied its biological properties: cultural, morphological, biochemical. Surface cultivation on differential media, microscopy in agar blocks and adhesive tape preparations, molecular genetic identification was carried out. The features of the formation of fungus colony are described, the characteristic morphological structures of the coelomycete, moderate fermentation of carbohydrates and the absence of urease activity are revealed. On the dextrose agar of Sabouraud nutrient medium, by 10-18 days, flat colonies of pale pink colour, with a pinkish-orange tint in the centre, yellowish along the edge, with a raised centre and relief radial stripes, were formed, the reverser was yellow-brown. The appearance of single growth tubes was noted within the first 12 hours, the massive division of single cells and the growth of filamentous filaments - 18 hours after sowing the spores. By the end of the second day, there is a powerful growth and active branching of the mycelium, the appearance of rudiments of pycnidia in the form of seals along the course of mature mycelial filaments, by the end of the third day, the formation of pycnidia and chlamydospores of the brown colour of various shades. Ripe transparent, unicellular, elliptical pycnospores emerge from pycnidia and located in the form of a mucous drop. The strain is characterized by moderate saccharolytic activity in relation to glucose, sucrose, mannose, mannitol, lactose, the almost complete absence of urease activity. Molecular genetic identification by the Sanger method made it possible to identify the Phoma macrostoma strain with 100% certainty and to deposit the nucleotide sequence in GenBank as isolate No. MN701978.1 Didymella macrostoma 104-Kz. Key words: biology of the pathogen, genetic identification, onychomycosis, pycnidia, coelomycetes

Характеристика редкого возбудителя онихомикоза Phoma macrostoma (син. Didymella macrostoma)

The article presents the results of studying the biological properties of the Phoma macrostomastrain, first described in Kazakhstan as the causative agent of onychomycosis. The authors obtained a pure culture of Phoma macrostoma coelomic, isolated from the affected nail plate of a patient in a narcological dispensary, and studied its biological properties: cultural, morphological, biochemical. Surface cultivation on differential media, microscopy in agar blocks and adhesive tape preparations, molecular genetic identification was carried out. The features of the formation of  fungus colony are described, the characteristic morphological structures of the coelomycete, moderate fermentation of carbohydrates and the absence of urease activity are revealed. On the dextrose agar of Sabouraud nutrient medium, by 10-18 days, flat colonies of pale pink colour, with a pinkish-orange tint in the centre, yellowish along the edge, with a raised centre and relief radial stripes, were formed, the reverser was yellow-brown. The appearance of single growth tubes was noted within the first 12 hours, the massive division of single cells and the growth of filamentous filaments - 18 hours after sowing the spores. By the end of the second day, there is a powerful growth and active branching of the mycelium, the appearance of rudiments of pycnidia in the form of seals along the course of mature mycelial filaments, by the end of the third day, the formation of pycnidia and chlamydospores of the brown colour of various shades. Ripe transparent, unicellular, elliptical pycnospores emerge from pycnidia and  located in the form of a mucous drop. The strain is characterized by moderate saccharolytic activity in relation to glucose, sucrose, mannose, mannitol, lactose, the almost complete absence of urease activity. Molecular genetic identification by the Sanger method made it possible to identify the Phoma macrostoma strain with 100% certainty and to deposit the nucleotide sequence in GenBank as isolate No. MN701978.1 Didymella macrostoma 104-Kz. Key words: biology of the pathogen, genetic identification, onychomycosis, pycnidia, coelomycetes

Aspergiloma pulmonar en paciente con síndrome de sobreposición: Reporte de caso

Introducción: La infección por Aspergillus spp. representa un reto diagnóstico y terapéutico para el clínico, puesto que existe un número aproximado de 180 especies. El pulmón es el principal órgano afectado por el Aspergillus debido a la alta capacidad esporulativa de este hongo, y a que sus conidias son lo suficientemente pequeñas para poder alcanzar el alveolo. Caso: Mujer de 41 años de edad con antecedente de lupus eritematoso sistémico, ingresó con un cuadro de disfagia, en el cual se confirmó la presencia de síndrome de sobreposición mediante perfil inmunológico. Posteriormente, mediante estudio imagenológico, realizado por tener tos y disnea, se encontró la presencia de una masa ovoidea en hemitorax derecho y al realizar una fibrobroncoscopia se evidenció que dicha lesión era compatible con un aspergiloma, por lo que se dio manejo antifúngico con una evolución clínica adecuada. Conclusión: El aspergiloma se presenta como una masa voluminosa constituida por filamentos miceliales, la cual se puede confundir con múltiples patologías principalmente de tipo tumoral, por lo que es necesario realizar biopsia de la misma.

Trichoderma harzianum: Inhibition of mycotoxin producing fungi and toxin biosynthesis

A quarter of the world-wide crop is spoiled by filamentous fungi and their mycotoxins and weather extremes associated with the climate change lead to further deterioration of the situation. The ingestion of mycotoxins causes several health issues leading in the worst case to cancer in humans and animals. Common intervention strategies against mycotoxin producing fungi, such as the application of fungicides, may result in undesirable residues and in some cases to a stress induction of mycotoxin biosynthesis. Moreover, development of fungicide resistances has greatly impacted pre- and postharvest fungal diseases. Hence there is the need to develop alternative strategies to reduce fungal infestation and thus mycotoxin contamination in the food chain. Such a strategy for natural competition of important plant-pathogenic and mycotoxin producing fungi could be Trichoderma harzianum, a mycoparasitic fungus. Especially in direct comparison to certain tested fungicides, the inhibition of different tested fungal species by T. harzianum was comparable, more sustainable and in some cases more effective, too. Besides substantially reduced growth rates, a transcriptional based inhibition of mycotoxin biosynthesis in the competed Aspergillus species could be shown. Furthermore it could be clearly observed by high-resolution Scanning Electron Microscopy (SEM) that T. harzianum actively attaches to the competitor species followed by subsequent enzymatic lysis of those mycelial filaments. The analyzed isolate of T. harzianum MRI349 is not known to produce mycotoxins. In this study it could be successfully proven that T. harzianum as a biological competitor is an effective complement to the use of fungicides.

Study of the Differentiation of Fusarium oxysporum f.sp. albedinis Chlamydospores on Different Culture Media

Chlamydospores of Fusarium oxysporum f.sp. albedinis are well known as fungus survival spores in soil, also act as a causal agent of Bayoud disease of the date palm. Till now, there are a little study in the literature about the favorable media for the formation of chlamydospores and the stages of chlamydogenesis. This study shows that rice flour based medium (45 chlamydospores per mm 2), oatmeal (31 chlamydospores per mm 2) and bean flour (27 chlamydospores per mm 2) tested for the first time, are among the media inducing the formation of chlamydospores in large numbers. The optimum formation of chlamydospores is observed on rice flour-based medium after 7 days of Original Research Article Smail et al.; ARRB, 18(4): 1-9, 2017; Article no.ARRB.35653 2 incubation at 18°C and pH 7. The effect of light does not seem very important on chlamydogenesis. However, relative humidity has a significant effect on the growth and chlamydogenesis of F. oxysporum f.sp. albedinis. The tested G 1 isolate grows and forms chlamydospores at relative humidities of 70 and 100%. The number of chlamydospores varies between 40.01 and 44.05 chlamydospores/mm 2. To form chlamydospores, cultures of F. oxysporum f.sp. albedinis need to be in contact with the favorable culture medium. Thus, the cultures develop and form more chlamydospores on a single layer of cellophane deposited on a culture medium, but show slower growth and do not form chlamydospores on two layers of cellophane. Chlamydospores of Fusarium oxysporum f.sp. albedinis are always at the extremity of the mycelial filaments. They differ in one to four cells in superimposed position. A terminal hyphal bulge leads to the formation of the terminal cell. The second cell is formed at the base of the first, and the process continues so that one can sometimes observed chlamydospores in bead-like chains.

Infection sous-cutanée disséminée par Scytalidium (Neoscytalidium) dimidiatum

S.dimidiatum (recently reclassified as N.dimidiatum) is a fungus that causes nail and/or superficial skin infection. It may also cause subcutaneous and deep infection, chiefly in immunocompromised patients. An 87-year-old male treated with oral corticosteroids for sarcoidosis consulted for violaceous cutaneous nodules on the back of his hands. Histopathological examination revealed epithelioid cell granulomas with numerous mycelial filaments and multiple spores. Culture of a biopsy sample resulted in growth of numerous colonies of S.dimidiatum and the patient was treated with intravenous amphotericin B. This organism is transmitted by direct or indirect contact with contaminated soil or plants. It mainly causes superficial skin and nail infections, and may result in deeper infections on rare occasions. We report a case of subcutaneous infection with S.dimidiatum in an immunocompromised patient (due to general steroid therapy) that was successfully treated using amphotericin B.

Infections rhinocérébrales chez l’immunodéprimé en hématologie

Invasive rhinosinusitis, occurring almost exclusively in immunosuppressed patients, is defined by the presence of local inflammation with vascular and osseous necrosis with extensive soft tissue extension. Imaging and bacteriological and even histological (mycelial filaments) criteria have been established. Because it can evolve to death in patients with hematological disorders, accurate diagnosis is important but difficult to achieve due to the non-specific nature of signs and symptoms. Imaging plays an important role with CT of the paranasal sinuses and MR imaging of the brain for early diagnosis and treatment in order to improve prognosis. We will present the imaging features of three cases of rhinocerebral infections, with two cases of fungal infection and one case of invasive bacterial sinus infection.

Phialemonium curvatum infection after bone marrow transplantation.

We report a case of cutaneous infection caused by Phialemonium curvatum GAMS et COOKE, 1983, after bone marrow transplantation. The genus Phialemonium was created by GAMS & MCGINNIS in 1983 including three new species: Ph. obovatum, Ph. curvatum and Ph. dimorphosporum, and represents an intermediate genus between Acremonium and Phialophora. Nowadays, the genus Phialemonium is considered to be a pheoid fungus which may cause the eventual lesions observed in pheo- and hyalohyphomycosis. Species of this genus have been described as opportunistic agents in humans and animals, mainly as a result of immunosuppression. In the present case, the patient had multiple myeloma and received an allogenic bone marrow transplant from his HLA-compatible brother. Two months after transplantation, he developed purplish and painful nodular lesions on the right ankle. Some of these lesions drained spontaneously and apparently hyaline mycelial filaments were observed, whose culture was initially identified as Acremonium sp. Subsequent studies showed that the fungus was Phialemonium curvatum. The infection was treated with amphotericin B, followed by ketoconazole. The patient was submitted to surgical debridement followed by two skin grafts to repair the bloody area. The duration of the treatment was 4 months and secondary prophylaxis with ketoconazole alone was maintained for one additional month. No recurrence was observed after discontinuation of treatment. The authors comment on the pathogenicity of the genus Phialemonium.

Pattern of cadmium accumulation and essential cations during growth of cadmium-tolerant fungi.

The present study evaluates the growth response of two strains of filamentous fungi; a Fusarium sp. and Alternaria tenuis, grown on both solid and liquid Czapek Dox medium amended with different concentrations of CdCl2. Colony extension and the mycelial dry weight of both fungi were significantly inhibited by high concentrations of cadmium. Extended lag phases and low growth rates resulted from cadmium administration. Cadmium drastically affected fungal morphogenesis by the production of stunted sterile thick mycelial filaments of the Fusarium sp. and chains of uncharacterized swellings instead of conidia in A. tenuis. Experiments showed that cadmium accumulation by the Fusarium sp. grown in liquid medium was a concentration dependent, and over the incubation time it displayed a plateau pattern. The cells grown on medium containing 0.25 mmol l(-1) CdCl2 accumulated up to 89 +/- 12 ,umol Cd (gm dw)(-l) after two days, falling to approximately 29 +/- 10 mol Cd (gm dw)(-1) after five days. At 0.5 mmol l(-1) CdCl2 treatment the maximum cellular cadmium content was approximately 132 +/- 14 micromol (gm dw)(-1), attained after 3 days, and decreased to degrees 98 +/- 9 micromol (gm dw)(-1) at the end of the incubation time. There was a simultaneous marked drop in cadmium content and pH of the growth medium during the first few days. The presence of cadmium markedly altered the cellular essential cations; K+ and Mg2+ being decreased while Na+ increased during the growth period. Such findings resulted a reverse pattern of cellular Na+/K+ ratio for cells grown on cadmium-containing medium in respect to the control treatment. The results are discussed in relation to a further dimension of cadmium effects that might reflect its toxicity, as well as the implication of cadmium extrusion for tolerance during fungal growth.

Ami1, an orthologue of the Aspergillus nidulans apsA gene, is involved in nuclear migration events throughout the life cycle of Podospora anserina.

The Podospora anserina ami1-1 mutant was identified as a male-sterile strain. Microconidia (which act as male gametes) form, but are anucleate. Paraphysae from the perithecium beaks are also anucleate when ami1-1 is used as the female partner in a cross. Furthermore, in crosses heterozygous for ami1-1, some crozier cells are uninucleate rather than binucleate. In addition to these nuclear migration defects, which occur at the transition between syncytial and cellular states, ami1-1 causes abnormal distribution of the nuclei in both mycelial filaments and asci. Finally, an ami1-1 strain bearing information for both mating types is unable to self-fertilize. The ami1 gene is an orthologue of the Aspergillus nidulans apsA gene, which controls nuclear positioning in filaments and during conidiogenesis (at the syncytial/cellular transition). The ApsA and AMI1 proteins display 42% identity and share structural features. The apsA gene complements some ami1-1 defects: it increases the percentage of nucleate microconidia and restores self-fertility in an ami1-1 mat+ (mat-) strain. The latter effect is puzzling, since in apsA null mutants sexual reproduction is quite normal. The functional differences between the two genes are discussed with respect to their possible history in these two fungi, which are very distant in terms of evolution.

Disseminated Scedosporium prolificans (S. inflation) Infection After Single-Lung Transplantation

This report concerns the first case of disseminated infection with Scedosporium prolificans (S. inflatum) that occurred in a patient who had received an organ transplant and was verified at autopsy. The patient underwent single (right)-lung transplantation and subsequently died on the 33rd postoperative day in a context of septic shock. S. prolificans was isolated from various specimens, including two cultured blood samples. The organism was associated with Candida albicans in some of these specimens. Autopsy revealed the presence of numerous nodular abscesses in the lungs, myocardium, kidneys, spleen, and gall bladder. These abscesses contained mycelial filaments and numerous oval conidia suggestive of Scedosporium species but no yeasts. MIC studies demonstrated the resistance of the S. prolificans isolate to amphotericin B, fluctyosine, miconazole, ketoconazole, and itraconazole, whereas the isolate of C. albicans was susceptible to amphotericin B, flucytosine, miconazole, and ketoconazole. From the data from our case and six published reports of cases of disseminated S. prolificans infection, it can be concluded that this filamentous fungus is a new agent responsible for the most serious mycoses in both neutropenic patients and patients who have undergone organ transplantation.

Mode of the absorption of water and nutrients by ascocarps of Tuber melanosporum and Tuber aestivum: a radioactive tracer technique

A simple technique has been developed to study the absorption capacity of the tufts of mycelial filaments, or hyphae, observed on both black and white truffles Tuber melanosporum and Tuber aestivum. These hyphae sprout from the tops of certain scales on the peridium of Tuber. They colonize the surrounding soil and could therefore exploit the nutrients from a large volume of soil. The ability to absorb organic and inorganic nutrients from a source other than the host is a necessary condition for the hypothesis we wished to test, namely that at some stage in its development the truffle ascocarp becomes autonomous. The absorption was demonstrated using autoradiography and liquid scintillation counting. We found that the tufts of hyphae are water permeable (3H2O). In addition, they absorb a sugar ([14C]mannose) and an anion ([32P]phosphate). An analysis of our results shows that the spatial distribution of [32P]phosphate is independent of that of tritiated water; the transport of phosphate is therefore not determined by water flux. The quantity and redistribution of the tracer depended on the application site, directly onto the peridium or on a mycelial tuft. The tufts increase the absorption of the tracer and influence its internal redistribution towards accumulation zones. Key words: ascocarp, Tuber melanosporum, Tuber aestivum, absorption, truffle nutrition.

Low voltage scanning electron microscopy study of naftifine activity on Microsporum canis.

Scanning electron microscopy (SEM) is at present considered a good way to observe the morphological alterations induced by an antifungal on pathogenic fungi. Owing to its high precision, low voltage scanning electron microscopy (LVSEM) improves the quality of observations. The Microsporum canis morphology alterations induced by naftifine at a concentration of 0.9 microgram ml-1 (10 times the minimum inhibitory concentration (MIC) for 7 days were studied in LVSEM. The young lateral ramifications and the aborted buds take on a granulous aspect. These granulations can be localized as brassard shapes around hyphae. The mycelial filaments often appear irregularly swollen with bulbous tips. Macroconidia are selectively covered with a microfibrillar network. In addition, LVSEM on control samples reveals pavimentous angular structures on the macroconidial surface and fine granulations on the filament surface of M. canis unknown until now. A cytological study with transmission electron microscopy (TEM) of filaments altered by naftifine permitted us to observe the disorganization of cell wall fibrillar structure, an excessive plasma membrane undulation and an intracytoplasmic accumulation of large vesicles with probably lipidic contents.