Yeasts take up iron by three main mechanisms. In the reductive uptake mechanism, specialized flavo-hemoproteins (Fre) dissociate extracellular ferric complexes by reduction involving trans-plasma membrane electron transfer. The resulting free iron is then imported by a high-affinity permease system (Ftr), coupled to a copper-dependent oxidase (Fet), which channels iron through the plasma membrane. As a consequence, iron uptake by this mechanism is dependent on the availability of copper. In the siderophore-mediated mechanism, siderophores excreted by the cells or produced by other bacterial or fungal species are taken up without prior dissociation, via specific, copper-independent high-affinity receptors. The iron is then dissociated from the siderophores intracellularly, probably by reduction. In the heme uptake mechanism, free heme or heme bound to hemoglobin is taken up as such, probably by endocytosis. Iron is released intracellularly after hydrolysis of the porphyrin ring catalyzed by heme oxygenase. Within the cell, iron is stored in vacuoles or in siderophores.
Iron can be mobilized from vacuoles by a reductive mechanism homologous to that found at the plasma membrane. Regulation of iron uptake and iron use are mediated by transcriptional regulators acting either as activators in iron-deficient conditions or as repressors in iron-rich conditions, according to the yeast species; these regulators thus adjust the iron uptake flux to the cell's requirements. In the baker's yeast,
Saccharomyces cerevisiae, a post-transcriptional mechanism is active under low iron conditions, involving the degradation of RNAs encoding inessential iron-utilizing proteins. Other fungi have mechanisms serving a similar purpose at the transcriptional level. Studies in
S. cerevisiae show that mitochondria are central to regulating cellular iron homeostasis, through the synthesis of iron-sulfur clusters.
Further reading:
Iron Uptake and Homeostasis in MicroorganismsLabels: fungal, fungi, Iron acquisition mechanisms, Iron transporters, Iron uptake in Yeasts, Iron uptake systems, Iron-homeostasis, Iron-uptake, mycology, Siderophores, yeast, Yeasts
The
aspergilli are a fascinating group of fungi exhibiting immense ecological and metabolic diversity. These include notorious pathogens such as
Aspergillus flavus, which produces aflatoxin, one of the most potent, naturally occurring, compounds known to man. Conversely, also included are other fungi, such as
A. oryzae, involved in the industrial production of soy sauce and sake or
A. niger used for the production of citric acid and enzymes such as glucose oxidase and lysozyme.
Such is the interest in
Aspergillus that, to date, the sequences of fifteen different
Aspergillus genomes have been determined providing scientists with an exciting resource to improve the understanding of
Aspergillus molecular genomics and act as a spring board for mining for new metabolites and novel genes of industrial or medical importance.
Further reading:
Aspergillus: Molecular Biology and GenomicsLabels: aflatoxin, aspergilli, aspergillus, Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, fungal, fungi
April 6 - 7, 2009. Economic and Social Impact of Fungal Deteriogens
Manchester, UK
Further informationOrganised by the British Mycological Society and the International Biodeterioration and Biodegradation Society. Session titles include: Fungal Deteriogen of Materials and their Conservation, Fungal Deteriogens and Food Spoilage, Impact of Fungal Deteriogens on Health, Economic Impact of Fungal Deteriogens. In addition there will be a number of posters.
Suggested reading: Microbial Biodegradation: Genomics and Molecular Biology and
Mycology booksLabels: biodegradation, biodeterioration, conference, deteriogens, fungal, microbiology conference, mycology
A list of conferences, meetings, symposia and workshops relating to all aspects of mycology, yeast and fungal science and medicine.
February 1 - 14, 2009. Comparative analysis of in vitro and in vivo
Candida albicans-host interaction systems
Madrid, Spain
Further informationFederation of European Biochemical Societies advanced practical and lecture course. The aim of this two-week course is to introduce students to the latest techniques of in vivo infection and ex-vivo/in vitro interaction models between the human pathogen
Candida albicans and the host.
Suggested reading: Candida BookMarch 17 - 22, 2009. 25th Fungal Genetics Conference
Asilomar, California, USA
Further informationBilled as the biggest worldwide conference on genetics of filamentous fungi.
Suggested reading: Aspergillus: Molecular Biology and GenomicsMarch 29 - 31, 2009. British Society for Medical Mycology (BSMM) Annual Scientific Meeting
Imperial College London, UK
Further informationTranslational Research in Medical Mycology
Suggested reading: Mycology BooksApril 6 - 7, 2009. Economic and Social Impact of Fungal Deteriogens
Manchester, UK
Further informationOrganised by the British Mycological Society and the International Biodeterioration and Biodegradation Society. Session titles include: Fungal Deteriogen of Materials and their Conservation, Fungal Deteriogens and Food Spoilage, Impact of Fungal Deteriogens on Health, Economic Impact of Fungal Deteriogens. In addition there will be a number of posters.
Suggested reading: Microbial Biodegradation: Genomics and Molecular Biology and
Mycology booksMay 25 - 29, 2009. The 17th Congress of The International Society for Human and Animal Mycology 2009 (ISHAM 2009)
Keio Plaza Hotel, Shinjuku, Tokyo, Japan
Further informationISHAM2009 will address recent developments in medical, veterinary and environmental mycology with a focus on human and animal health. More than 30 symposia with distinguished speakers are planned, including keynote lectures, luncheon and evening seminars, and a new Poster Forum.
Suggested reading: Mycology BooksJune 21 - 26, 2009 Mycotoxins and Phycotoxins
New London, NH, USA
Further informationGordon Research Conference. Presentation of leading-edge research on fungal, algal, and cyanobacterial toxins and the organisms that produce them. This multidisciplinary gathering will encompass the biology, ecology, genetics, chemistry and the public health and economic impacts
Suggested reading: Aspergillus: Molecular Biology and Genomics July 19 - 24, 2009. 24th International Conference on Yeast Genetics and Molecular Biology
Manchester, UK
Further informationKey conference themes will include: Cell Cycle and Morphogenesis, Control of Gene Expression, Genomes and Evolution, Protein Trafficking, Signal Transduction, Systems Biology, Yeasts as Cell Factories, Yeasts as Models for Ageing and Human Disease, Yeasts as Pathogens
Suggested reading: Mycology BooksAugust 26 - 29, 2009. Pasteur's Legacy: Yeast for Health and Biotechnologies (the 27th International Specialised Symposium on Yeast)
Institut Pasteur, Paris, France
Further informationSeptember 1 - 4, 2009. British Mycological Society annual scientific meeting
Dundee, UK
Further informationThe Fungal Cell. Including cellular organisation, metabolism and cellular regulation, fungal growth, morphogenesis and differentiation, and fungal interactions with other organisms including bacteria and plants.
Suggested reading: Mycology BooksOctober 18 - 21, 2009. 4th Trends in Medical Mycology TIMM4
Athens, Greece
Further informationOrganized jointly by the European Confederation of Medical Mycology (ECMM) and by the Infectious Diseases Group of the European Organization for Research and Treatment of Cancer (IDG-EORTC). The scientific programme will include plenary sessions on fungal infections in both immunocompromised and immunocompetent hosts led by an internationally renowned faculty giving plenary talks, round table sessions, and meet-the-expert meetings. The poster session will encourage one-to-one discussions between faculty, presenters and delegates. The meeting is designed for infectious disease specialists, haematologists, oncologists, transplant physicians, microbiologists, immunologists, dermatologists, intensivists and others with interest in medical mycology.
Suggested reading: Mycology BooksOctober 29 - 31, 2009. Mycology MasterClass IV
Hamilton Island, QLD, Australia
Further informationAdvanced medical mycology course for specialists and trainees in infectious diseases, microbiology, haematology and intensive care medicine and for laboratory scientists/technicians specialising in medical mycology.
Suggested reading: Aspergillus: Molecular Biology and GenomicsLabels: aspergillus, conference, fungal, fungi, mycology, yeast