Salvinia spp. are small, floating ferns that grow in long chains of two oval leaves and a root-like third leaf. S. natans (L.) All., a native floating fern distributed in paddy fields, ponds, and ditches in Taiwan, has become critically endangered. Another two exotic species, S. auriculata Aublet (eared salvinia) and S. molesta Mitchell (giant salvinia), are sold in increasing frequency at local flower markets and aquarium shops and pose a serious threat when they find their way into the natural environment. Brown spot of S. auriculata was found in a home aquarium in December 2006 in Chiayi, Taiwan. Symptoms of the disease included many, irregular, dark brown spots on both upper and lower leaf surfaces. Lesions on the upper surface of the leaves were covered with white patches of mycelia and abundant conidia. Small pieces (approximately 2 × 2 mm) of diseased leaf tissue from the margin of individual lesions were surface disinfected in 1% sodium hypochlorite solution for 1 min, rinsed in sterile water, plated on water agar, and incubated at 25°C. Six isolates of the fungus were then isolated and transferred to potato dextrose agar (PDA). Isolate Cs0701 was identified morphologically as Simplicillium lanosoniveum (van Beyma) Zare & W. Gams on the basis of morphology of asexual reproduction structures and rDNA sequence analysis (1). In culture, this fungus formed whitish-to-whitish yellow, pulvinate colonies with matted surfaces. The reverse side of cultures was yellow to light brown. Small, ovate to spherical, hyaline conidia, 2.2 to 3.0 × 1.6 to 2.0 μm (average 2.4 × 1.9 μm) were formed. To confirm the identity of the fungus, PCR amplification and DNA sequencing of the internal transcribed spacer (ITS1-5.8S-ITS2 rRNA gene cluster) was conducted on isolates Cs0701 and Cs0702. The sequence of the PCR product was compared with sequences of closely related species listed in the GenBank database. Except for a single nucleotide, the ITS sequence of both isolates (480 bp; GenBank Accession No. EU939525) was identical to the rRNA of Simplicillium lanosoniveum (GenBank Accession No. AJ292396). Koch's postulates were performed to confirm the pathogenicity of the fungus on S. auriculata and S. molesta. After 14 days of growth on PDA, a spore suspension of isolate Cs0701 (10 spores per ml) was sprayed onto approximately 5 and 10 g of healthy S. auriculata and S. molesta plants, respectively, floated in 500-ml beakers filled with 300 ml of tap water. All treatments, including controls misted with sterile water, were replicated three times. The beakers were covered with plastic bags and placed in a growth chamber maintained at 25°C with 12-h fluorescent light cycles. After 2 days, the bags were removed. Symptoms developed on all inoculated plants 4 days after inoculation. In all cases, typical brown spots were observed. Simplicillium lanosoniveum was reisolated from all surface-disinfested infected tissues. Control plants developed no symptoms. Six isolates of the fungus are being maintained at the Department of Microbiology and Immunology, National Chiayi University, Taiwan. To our knowledge, this is the first report of Simplicillium lanosoniveum causing brown spot of S. auriculata and S. molesta in Taiwan. Reference: (1) R. Zare and W. Gams. Nova Hedwigia 73:1, 2001.

A previously unknown symbiotic fungus DT06 has been isolated from the single-celled blue-green alga Chroococcus sp. The sequences of ITS1, 5.8S rDNA and ITS2 regions of DT06 have a high similarity with that of Simplicillium (98%), which is closely related to Simplicillium lanosoniveum based on further phylogenetic analysis. However, DT06 produces unusual exocellular crystals with its conidium size twice that of S. lanosoniveum. Hence, DT06 is proposed to be a varietas of S. lanosoniveum and named as S. lanosoniveum var. Tianjinienss. Dong. (Type specimen was deposited at China General Microbiological Culture Collection Center, Number: CGMCC4460.). The striking character of DT06 is its massive production of a unique extracellular polysaccharide, which is composed of glucose and galactose and linked by 1-4 and 1-6 glycoside bonds according to UV, IR and NMR analysis. Therefore, DT06 may represent a new source of bioactive products, and also, its unusual symbiotic partnership with blue-green algae provides a model for investigating the interaction between photoautotrophic and heterotrophic micro-organisms in aquatic ecosystems.A novel fungus (Simplicillium) symbiotic with a single-celled blue-green alga Chroococcus sp. and its major primary metabolite have been isolated and identified. These findings broaden the scope of symbiotic fungi and provide a unique extracellular polysaccharide with potential applications in food industry.© 2013 The Society for Applied Microbiology.

The recycling of photosynthetically fixed carbon by the action of microbial plant cell wall hydrolases is a fundamental biological process that is integral to one of the major geochemical cycles and, in addition, has considerable industrial potential. Enzyme systems that attack the plant cell wall contain noncatalytic carbohydrate-binding modules (CBMs) that mediate attachment to this composite structure and play a pivotal role in maximizing the hydrolytic process. Anaerobic fungi that colonize herbivores are the most efficient plant cell wall degraders known, and this activity is vested in a high molecular weight complex that binds tightly to the plant cell wall. To investigate whether plant cell wall attachment is mediated by noncatalytic proteins, a cDNA library of the anaerobic fungus Piromyces equi was screened for sequences that encode noncatalytic proteins that are components of the cellulase-hemicellulase complex. A 1.6-kilobase cDNA was isolated encoding a protein of 479 amino acids with a M(r) of 52548 designated NCP1. The mature protein had a modular architecture comprising three copies of the noncatalytic dockerin module that targets anaerobic fungal proteins to the cellulase-hemicellulase complex. The two C-terminal modules of NCP1, CBM29-1 and CBM29-2, respectively, exhibit 33% sequence identity with each other but have no homologues in protein data bases. A truncated form of NCP1 comprising CBM29-1 and CBM29-2 (CBM29-1-2) and each of the two individual copies of CBM29 bind primarily to mannan, cellulose, and glucomannan, displaying the highest affinity for the latter polysaccharide. CBM29-1-2 exhibits 4-45-fold higher affinity than either CBM29-1 or CBM29-2 for the various ligands, indicating that the two modules, when covalently linked, act in synergy to bind to an array of different polysaccharides. This paper provides the first report of a CBM-containing protein from an anaerobic fungal cellulase-hemicellulase complex. The two CBMs constitute a novel CBM family designated CBM29 whose members exhibit unusually wide ligand specificity. We propose, therefore, that NCP1 plays a role in sequestering the fungal enzyme complex onto the plant cell wall.

There is increasing interest in the human colonic microbiota and in the way its metabolic activities impact on host health and well-being. For most practical purposes, however, the large bowel is inaccessible for routine investigation, and a variety of animal and in vitro model systems have been developed to study the microbiota. In vitro models range from simple closed systems using pure or defined mixed populations of bacteria, or faecal material, to more sophisticated complex multistage continuous cultures that are able to simulate many of the spatial, temporal and environmental attributes that characterize microbiological events in different regions of the large gut. Recent developments using these systems have enabled modelling of surface colonisation and biofilm development, a hitherto neglected area of study.

Environmental microbiology is undergoing a dramatic revolution due to the increasing accumulation of biological information and contextual environmental parameters. This will not only enable a better identification of diversity patterns, but will also shed more light on the associated environmental conditions, spatial locations, and seasonal fluctuations, which could explain such patterns. Complex ecological questions may now be addressed using multivariate statistical analyses, which represent a vast potential of techniques that are still underexploited. Here, well-established exploratory and hypothesis-driven approaches are reviewed, so as to foster their addition to the microbial ecologist toolbox. Because such tools aim at reducing data set complexity, at identifying major patterns and putative causal factors, they will certainly find many applications in microbial ecology.

Sporovexins A-C (1-3) and 3'-O-desmethyl-1-epipreussomerin C (4) have been isolated from liquid cultures of the coprophilous fungus Sporormiella vexans (JS 306). The structures of these new metabolites were elucidated on the basis of MS and NMR analysis. Compounds 1 and 4 show antifungal activity against competitor fungi, as well as antibacterial effects.