A Study on the Synthetic Characteristics of the Extracellular Polysaccharide (EPS) of Ganoderma lucidum Cultured in Batch Fermentation Using a Kinetic Model

The synthetic characteristics of the extracellular polysaccharide (EPS) of Ganoderma lucidum in batch fermentation were studied. The result showed that the production of EPS was partially growth-associated. The cell dry weight (CDW) and EPS reached 15.56 g·L⁻¹ and 3.02 g·L⁻¹, respectively. The yield of EPS to cell dry weight (Y_p/x) was 0.19. On the basis of the test results of batch fermentation, a kinetic model was proposed by using the Logistic equation for cell growth, the Luedeking–Piret equation for EPS production, and the Luedeking-piret-like equation for the consumption of glucose as substrate. The calculated results using these models were satisfactorily compared with the experimental data under various concentrations of glucose, and the average of relative errors was found to be not more than 5%. The kinetic model had practical guidance interesting in producing PES by Ganoderma lucidum.     

Anti-hepatitis B activities of ganoderic acid from Ganoderma lucidum

Ganoderic acid, from Ganoderma lucidum, at 8 μg/ml inhibited replication of hepatitis B virus (HBV) in HepG2215 cells over 8 days. Production of HBV surface antigen and HBV e antigen were 20 and 44% of controls without ganoderic acid. Male KM mice were significantly protected from liver injury, induced with carbon tetrachloride, by treatment with ganoderic acid at 10 mg and 30 mg/kg·d (by intravenous injection) 7 days. Ganoderic acid at the same dosage also significantly protected the mice from liver injury induced by M. bovis BCG plus lipopolysaccharide (from Escherichia coli 0127:B8).     

Significance of inoculation density control in production of polysaccharide and ganoderic acid by submerged culture of Ganoderma lucidum

Control of inoculation density was significant for cell growth, morphology, and production of polysaccharide and ganoderic acid in submerged culture of the higher fungus Ganoderma lucidum. A maximal cell concentration of 15.7 g dry cell weight (DW)/l was obtained at an inoculation density of 330 mg DW/l. For inoculation density within the range of 70–670 mg DW/l, a large inoculation density led to a small pellet size and high production of extracellular and intracellular polysaccharides, while a relatively big pellet size and high accumulation of ganoderic acid were observed at a low inoculation density. It was also shown that small pellet size resulted in high polysaccharide production, while large pellet size led to high production of ganoderic acid.     

Cytotoxic triterpenoids from Ganoderma lucidum

A systematic study of the metabolites in Ganoderma lucidum led to isolation of 43 triterpenoids, six of them (1-6) are hitherto unknown. The structures of the latter were elucidated on the basis of spectroscopic studies and comparison with the known related compounds. All of the compounds were assayed for their inhibitory activities against human HeLa cervical cancer cell lines. Some compounds exhibit significant cytotoxicity, and their structure-activity relationships are discussed.     

A new ecdysteroid and other constituents from two Dioscorea species

Phytochemical investigation of the rhizome of Dioscorea dumetorum has led to the isolation by several chromatographic steps on normal and reversed phase silica gel of a new ecdysteroid, (20R)-5β,11α,20-trihydroxyecdysone (1), and two known ecdysteroids, ajugasterone C (2) and herkesterone (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR (COSY, TOCSY, HSQC and HMBC). This is the first report on the occurrence of phytoecdysteroids in the Dioscoreaceae family. These compounds were devoid of antifungal activity against three Candida species (Candida albicans, Candida glabrata and Candida tropicalis, MIC > 200 μg/ml).     

Domoic acid production by Pseudo-nitzschia australis and Pseudo-nitzschia calliantha isolated from North Chile

The morphology and toxicity of the four ubiquitous species belonging to the genus Pseudo-nitzschia found in mixed blooms of phytoplankton from northern Chilean waters were studied. The phytoplankton samples and cultures obtained were identified by scanning electron microscopy, revealing the presence of Pseudo-nitzschia australis, P. calliantha, P. pseudodelicatissima and P. subfraudulenta. This is the first report of P. calliantha in northern Chile. Toxin analyses using the LC–MS method confirmed the presence of domoic acid in P. australis and P. calliantha. Domoic acid was not detected in cultures of P. subfraudulenta. This study therefore confirms P. australis and P. calliantha as an unequivocal source of domoic acid in Chilean waters. P. australis is probably the most important producer of amnesic shellfish toxin in view of its domoic acid content. However, more research is needed to evaluate the potential for toxin production in P. pseudodelicatissima.     

A new triterpenic acid from the wood rotting fungi

A new triterpenic acid, assigned the trivial name polyporenic acid D, has been isolated from the wood rotting fungus Polyporus officinalis. It has been shown to have the structure 3α-hydroxy-4,4,14α-trimethyl-5α-ergosta-8, 24(28)-dien-26-oic acid.     

Fatty acid composition of lipids from mushrooms belonging to the family Boletaceae

The non-polar lipid content and fatty acid (FA) composition of 11 mushroom species of the family Boletaceae were determined. The non-polar lipid content ranged from 2.0 (Leccinum aurantiacum and Boletus erythropus) to 5.4 % (w/w) d.w. (Suillus grevillei) with an average value of 2.9 %. More than 25 different FAs were found in the mushroom lipids. Unsaturated FAs, mainly linoleic and oleic acids, accounted for about 83 % of the total FAs, while palmitic acid was the main saturated FA. Some FAs are identified for the first time in Boletaceae and in higher Basidiomycetes (cis-11,12-methyleneoctadecanoic acid, 7-cis,10-cis hexadecadienoic) or in fungi (cis-11,12-methyleneoctadecanoic acid). There were significant differences (P < 0.05) in the contents of specific FAs between mushroom species.     

ThenadB gene ofSalmonella typhimurium complements the nicotinic acid auxotrophy ofShigella flexneri

Shigella species are characteristically nicotinic acid (NA) auxotrophs. The invasiveS. flexneri strain M90T, transformed with the multicopy plasmid pZT349 encoding thenadB gene ofSalmonella typhimurium, can grow in minimal glucose medium without exogenous NA, whereas, M90T containing the control vector, pUC18 does not, suggesting that this species lacksl-aspartic acid oxidase, the first enzyme in the de novo NAD biosynthetic pathway. The estimated growth rate of strain M90T (pZT349) in HeLa cells was identical to that of M90T (pUC18), indicating the available intracellular concentration of NA is not limiting for bacterial growth.     

A new species of Sarcostemma (Apocynaceae-Asclepiadoideae-Asclepiadeae) from Yemen

Sarcostemma areysianum Bruyns is described from the southern mountains of Yemen. It appears to be most closely related to S. arabicum Bruyns & P. Forst. and S. socotranum Lavranos, differing from both by the taller gynostegium with narrow, mostly acute inner corona lobes. A key to the species from Arabia and Socotra is provided.     

A new fungal genus, Teracosphaeria, with a phialophora-like anamorph (Sordariomycetes, Ascomycota)

The new genus and species Teracosphaeria petroica is described for a perithecial ascomycete and its anamorph occurring on decayed wood collected in New Zealand. The fungus produces immersed, non-stromatic ceratosphaeria-like perithecia in nature, with hyaline, septate ascospores produced in unitunicate, non-amyloid asci. The anamorph produced in vitro is phialophora-like with lightly pigmented phialides terminating in flaring, deep collarettes that are often noticeably brown with conspicuous periclinal thickening. Phylogenetic analysis of LSU rDNA sequence data indicates that this fungus is distinct from morphologically similar fungi classified in the Chaetosphaeriales, the Trichosphaeriales or the Magnaporthaceae. It forms a monophyletic group with recently described, chaetosphaeria-like ascomycetes, such as the pyrenomycete genus Mirannulata, and shows affinity with the anamorphic species Dictyochaeta cylindrospora. The usefulness of describing anamorph genera for morphologically reduced anamorphs, when anamorph characteristics are actually part of the holomorph diagnosis, is discussed. An apparently contradictory example of the so-called Cordana and Pseudobotrytis anamorphs of Porosphaerella spp. is also discussed.     

A polysaccharide from Lichina pygmaea and L. confinis supports the recognition of Lichinomycetes

The lichen-forming order Lichinales, generally characterized by prototunicate asci and the development of thalli with cyanobacteria, has recently been recognized as a separate class of ascomycetes, Lichinomycetes, as a result of molecular phylogenetic studies. As alkali and water-soluble (F1SS) polysaccharides reflect phylogeny in other ascomycetes, a polysaccharide from Lichina pygmaea and L. confinis was purified and characterized to investigate whether these F1SS compounds in the Lichinomycetes were distinctive. Nuclear magnetic resonance (NMR) spectroscopy and chemical analyses revealed this as a galactomannan comprising a repeating unit consisting of an α-(1→6)-mannan backbone, mainly substituted by single α-galactofuranose residues at the O-2- or the O-2,4- positions linked to a small mannan core. With the exception of the trisubstituted mannopyranose residues previously described in polysaccharides from other lichens belonging to orders now placed in Lecanoromycetes, the structure of this galactomannan most closely resembles those found in several members of the Onygenales in Eurotiomycetes. Our polysaccharide data support molecular studies showing that Lichina species are remote from Lecanoromycetes as the galactofuranose residues are in the α-configuration. That the Lichinomycetes were part of an ancestral lichenized group can not be established from the present data because the extracted polysaccharide does not have the galactofuranose residue in the β configuration; however, the data does suggest that an ancestor of the Lichinomycetes contained a mannan and was part of an early radiation in the ascomycetes.     

Limonoids from the fruits of Melia toosendan

Four (1–4) new and seven known limonoids were isolated from the EtOH extract of the fruits of Melia toosendan. The structures of the new compounds were established on the basis of spectroscopic methods to be 12-O-methyl-1-O-deacetylnimbolinin B (1), 12-O-methy-1-O-tigloyl-1-O-deacetylnimbolinin B (2), 12-O-ethylnimbolinin B (3), and 1-O-cinnamoyl-1-O-debenzoylohchinal (4). Additionally, two new tirucallane-type triterpenoids, named meliasenins S (5) and T (6), were obtained from the same fractions during purification of the limonoids.     

Influence of NaCl and Na2SO4 on the kinetics and dye decolorization ability of crude laccase from Ganoderma lucidum

In a solid state medium using yellow passion fruit waste as substrate, the basidiomycete Ganoderma lucidum produced a laccase as the main ligninolytic enzyme. This crude enzyme presented Michaelian behavior with both substrates tested, namely 3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and the anthraquinone dye remazol brilliant blue R (RBBR). The K_M’s for these substrates were, respectively, 0.232 × 10⁻³ and 0.602 × 10⁻³ M. The actions of NaCl and Na₂SO₄, two important salts usually found in textile wastewaters, were investigated. The enzyme was inhibited by NaCl, but not by Na₂SO₄. Inhibition by NaCl was of the mixed type with two different inhibition constants. The enzyme was able to completely decolorize RBBR in the presence of 1.0 M Na₂SO₄ and 50% decolorization was found in the presence of 0.1 M NaCl. Such properties certainly make the enzyme a good agent for textile dye effluent treatment considering the fact that wastewaters of this industry usually contain high concentrations of NaCl and Na₂SO₄.     

A new species of Phaeohelotium from Nothofagus forests in Argentina and Chile, with a key to the Southern Hemisphere species

Phaeohelotium nothofagi, sp.nov., found on fallen wood and leaves of Nothofagus dombeyi, is described and illustrated. The fungus is characterized by pale yellow discs, and fumose ascospores with asperulate walls. A key with distributional data for the five species of the genus now known in the Southern Hemisphere is provided.     

Cumanensic acid, a new chromene isolated from Piper cf. cumanense Kunth. (Piperaceae)

A new chromene, cumanensic acid (1), together with eight known compounds have been isolated from the aerial part of Piper cf. cumanense Kunth (Piperaceae). Chromene structure was identified on the basis of spectroscopic analysis and comparison with literature data. The compound showed antifungal activity against Fusarium oxysporum f. sp. dianthi and Botrytis cinerea.