A reappraisal of the terverticillate penicillia using biochemical, physiological and morphological features. I. Numerical taxonomy

Current Fungal Taxonomy and Developments in the Identification System

A functional identification system is the core and basis of fungal taxonomy, which provides sufficient diagnostic characteristics for species delimitation. Phenotype-based identification systems have exhibited significant drawbacks, such as being laborious and time-consuming. Thus, a molecular-based identification system (rDNA, DNA fingerprint, etc.) is proposed for application to fungi that lack reliable morphological characteristics. High Throughput Sequencing also makes great contributions to fungal taxonomy. However, the formal naming of nonculturable fungi from environmental sequencing is a significant challenge. Biochemical profile-based identification systems have outstanding value in fungal taxonomy and can occasionally be indispensable. This method utilizes biomarker metabolites and proteins that are expected to be unequivocal and stable. Of these, Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry has become the method of choice for chemotaxonomy. In sum, these described identification systems cannot solve all problems of species delimitation, and considerable attention to the updating of fungal nomenclature, standardization of techniques, knowledge sharing, and dissemination will be necessary.

Morphological, physiological, biochemical and molecular characterization of statin-producing Penicillium microfungi isolated from little-explored tropical ecosystems

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Natural statins produced by microfungi are extremely successful drugs.

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Fungal producers of statins were isolated from soils of unique tropical habitats.

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Three novel statin-producing Penicillium strains were characterized and identified.

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Pravastatin was produced by the identified fungal cultures directly.

As hypercholesterolemia is a primary risk factor for coronary artery disease and stroke, there is now an increasing demand for cholesterol-lowering drugs. Statins are a group of extremely successful drugs that lower the cholesterol level in the blood. Natural statins are produced by fermentation using different species of microorganisms. The overall aim of the present study was to identify statin-producing microfungi, which were isolated from different types of little-explored mangrove and oil palm plantation soils. Isolated fungal cultures were characterized on the basis of morphological, physiological, biochemical, and molecular features. Morphological variability was detected amongst the fungal isolates in regard to colony morphology, conidiophores structures, and conidia coloration. Based on their physiological properties and enzyme assays, rapid differentiation of statin-producing isolates was achieved. Further molecular characterization allowed reliable identification of the selected Penicillium microfungi up to the species level. The identified Penicillium cintrinum ESF2M, Penicillium brefeldianum ESF21P, and Penicillium janthinellum ESF26P strains have a scientific interest as novel wild-type producers of natural statins.

Isolation, Purification, and Characterization of Heparinase from Streptomyces variabilis MTCC 12266

Arterial/venous thrombosis is the major cardiovascular disorder accountable for substantial mortality; and the current demand for antithrombotic agents is extensive. Heparinases depolymerize unfractionated heparin (UFH) for the production of low molecular-weight heparins (LMWHs; used as anticoagulants against thrombosis). A microbial strain of Streptomyces sp. showing antithrombotic activity was isolated from the soil sample collected from north India. The strain was characterized by using 16S rRNA homology technique and identified as Streptomyces variabilis MTCC 12266 capable of producing heparinase enzyme. This is the very first communication reporting Streptomyces genus as the producer of heparinase. It was observed that the production of intracellular heparinase was [63.8 U/mg protein (specific activity)] 1.58 folds higher compared to extracellular heparinase [40.28 U/mg protein]. DEAE-Sephadex A-50 column followed by Sepharose-6B column purification of the crude protein resulted 19.18 folds purified heparinase. SDS-PAGE analysis of heparinase resulted an estimated molecular-weight of 42 kDa. It was also found that intracellular heparinase has the ability to depolymerize heparin to generate LMWHs. Further studies related to the mechanistic action, structural details, and genomics involved in heparinase production from Streptomyces variabilis are warranted for large scale production/purification optimization of heparinase for antithrombotic applications.

Physiological and biochemical characterization of Trichoderma harzianum, a biological control agent against soilborne fungal plant pathogens

Monoconidial cultures of 15 isolates of Trichoderma harzianum were characterized on the basis of 82 morphological, physiological, and biochemical features and 99 isoenzyme bands from seven enzyme systems. The results were subjected to numerical analysis which revealed four distinct groups. Representative sequences of the internal transcribed spacer 1 (ITS 1)-ITS 2 region in the ribosomal DNA gene cluster were compared between groups confirming this distribution. The utility of the groupings generated from the morphological, physiological, and biochemical data was assessed by including an additional environmental isolate in the electrophoretic analysis. The in vitro antibiotic activity of the T. harzianum isolates was assayed against 10 isolates of five different soilborne fungal plant pathogens: Aphanomyces cochlioides, Rhizoctonia solani, Phoma betae, Acremonium cucurbitacearum, and Fusarium oxysporum f. sp. radicis lycopersici. Similarities between levels and specificities of biological activity and the numerical characterization groupings are both discussed in relation to antagonist-specific populations in known and potential biocontrol species.

Ochratoxin production by Aspergillus species

Ochratoxin production was tested in 172 strains representing species in sections Fumigati, Circumdati, Candidi, and Wentii of the genus Aspergillus by an immunochemical method using a monoclonal antibody preparation against ochratoxin A. Ochratoxin A was detected in Aspergillus ochraceus, A. alliaceus, A. sclerotiorum, A. sulphureus, A. albertensis, A. auricomus, and A. wentii strains. This is the first report of production of ochratoxins in the latter three species. Ochratoxin production by these species was confirmed by high-performance thin-layer chromatography and by high-performance liquid chromatography. The chemical methods also indicated the production of ochratoxin B by all of the Aspergillus strains mentioned above.