Lessons from the genome sequence of Neurospora crassa: tracing the path from genomic blueprint to multicellular organism

We present an analysis of over 1,100 of the approximately 10,000 predicted proteins encoded by the genome sequence of the filamentous fungus Neurospora crassa. Seven major areas of Neurospora genomics and biology are covered. First, the basic features of the genome, including the automated assembly, gene calls, and global gene analyses are summarized. The second section covers components of the centromere and kinetochore complexes, chromatin assembly and modification, and transcription and translation initiation factors. The third area discusses genome defense mechanisms, including repeat induced point mutation, quelling and meiotic silencing, and DNA repair and recombination. In the fourth section, topics relevant to metabolism and transport include extracellular digestion; membrane transporters; aspects of carbon, sulfur, nitrogen, and lipid metabolism; the mitochondrion and energy metabolism; the proteasome; and protein glycosylation, secretion, and endocytosis. Environmental sensing is the focus of the fifth section with a treatment of two-component systems; GTP-binding proteins; mitogen-activated protein, p21-activated, and germinal center kinases; calcium signaling; protein phosphatases; photobiology; circadian rhythms; and heat shock and stress responses. The sixth area of analysis is growth and development; it encompasses cell wall synthesis, proteins important for hyphal polarity, cytoskeletal components, the cyclin/cyclin-dependent kinase machinery, macroconidiation, meiosis, and the sexual cycle. The seventh section covers topics relevant to animal and plant pathogenesis and human disease. The results demonstrate that a large proportion of Neurospora genes do not have homologues in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. The group of unshared genes includes potential new targets for antifungals as well as loci implicated in human and plant physiology and disease.

Three new peroxides from the sponge Plakinastrella species

Two new five-membered-ring peroxide acids, plakinic acid F (3) and epiplakinic acid F (4), and a new peroxide-lactone, plakortolide F (5), were isolated from a sponge of the genus Plakinastrella collected from Felicite Island, Seychelles. The structures were elucidated through spectral analysis. The free acids 3 and 4 exhibit moderate antifungal activity against Candida albicans with minimum inhibitory concentrations of 25 micrograms/mL (SDB) and 3.1 micrograms/mL (RPMI) for 3, and 25 micrograms/mL (SDB) and 6.25 micrograms/mL (RPMI) for 4, respectively. Both also showed moderate in vitro inhibition of Aspergillus fumigatus with IC90's of 25 micrograms/mL.

New bioactive peroxides from marine sponges of the family plakiniidae

In our continuing program to identify compounds with antifungal properties, the ethanol extracts of two sponges of the family Plakinidae were found to inhibit the growth of the fungal pathogens Candida albicans and Aspergillus fumigatus. From these organisms three new compounds and five known compounds have been identified. A new 1,2-dioxane ring peroxide acid, 1, has been isolated from the sponge Plakortis halichondrioides along with five known compounds. Two new 1,2-dioxolane peroxide acids, 3 and 4, have been isolated from the sponge Plakinastrella onkodes. The structures were established by interpretation of spectral data. The three new compounds exhibit moderate activity against the fungal pathogen C. albicans with MICs of 5, 1.6, and 1.6 microg/mL respectively, for 1, 3, and 4. Compound 1 also showed in vitro inhibition of the fungal pathogen A. fumigatus with an IC(90) value of 5.6 microg/mL.

Cloning heterologous genes: problems and approaches

Model fungi such as Neurospora crassa, Aspergillus niger, and Saccharomyces cerevisiae have provided a wealth of genetic information and are currently the object of cooperative genome sequencing projects. Many agriculturally and medically economic important pathogenic fungi, however, are less well characterized, which makes it difficult to study their genes and gene products. Gene sequences from model fungi offer a unique opportunity to clone cognate genes from pathogenic counterparts. In this review, we propose three basic strategies for cloning such genes: Functional complementation, sequence similarity, and genetic linkage. These strategies involve Southern hybridization, cloning, library screening, genetic complementation, and the polymerase chain reaction. We review the major problems encountered using these strategies and outline useful solutions to these difficulties.