Development of an activation tagging system for the basidiomycetous medicinal fungus Antrodia cinnamomea

This study describes the development of an efficient and reliable activation tagging system for the medicinal fungus Antrodia cinnamomea. For successful Agrobacterium tumefaciens-mediated transformation, different parameters were considered. The Agrobacterium concentration of 5 × 10⁸ cfu ml⁻¹, 1 mm acetosyringone, 25-d-old mycelia at 0.2 g ml⁻¹, and co-culture period of 6 d were found to be the most optimal conditions for enhancing the transformation efficiency. The mitotic stability of transferred DNA (T-DNA) was demonstrated by growing eight randomly selected putative transformants in malt extract agar medium for five subcultures. Insertion of T-DNA into the genome of transformants was confirmed by PCR and Southern hybridization. Results showed that 88 % of the mutants contained a single T-DNA insertion. Two of the mutants were observed with different triterpenoid profiles compared with the untransformed cultures. Our results suggest a new functional genomics approach to tag the triterpenoid biosynthesis genes in A. cinnamomea.     

Triterpenoids from the fungus Ganoderma lucidum

Ten novel components, ganoderic acid, ganoderenic acid and lucidenic acid derivatives, were isolated from the fruiting body of the fungus Ganoderma lucidum. Their structures were elucidated mainly by spectroscopic and chemical methods.     

灵芝免疫调节蛋白LZ-8的制备和晶体分析

LZ-8蛋白是从灵芝菌丝中分离到的真菌免疫调节蛋白,具有多种免疫调节功能,然而这一蛋白的作用机制尚不清楚。通过蛋白质晶体结构的解析,能够得到蛋白质空间结构特点,从而阐述蛋白质功能的机制。旨在得到LZ-8蛋白的晶体,并获得空间结构数据。以pET21a为表达载体,获得诱导表达的rLZ-8,通过亲和层析、分子筛凝胶层析和阴离子交换层析纯化,蛋白纯度在98%以上,采用悬滴气相扩散法得到蛋白晶体,并获得3.2?数据,为进一步对真菌免疫调节蛋白功能和结构的研究奠定了基础。     

Chitin and chitosan biopolymer production from the Iranian medicinal fungus Ganoderma lucidum: Optimization and characterization

Abstract

Chitin and chitosan with unique properties and numerous applications can be produced from fungus. The production of chitin and chitosan from the mycelia of an Iranian Ganoderma lucidum was studied to improve cell growth and chitin productivity. Inoculum size and initial pH as two effective variables on the growth of G. lucidum and chitin production were optimized using response surface method (RSM) by central composite design (CCD). The results verified the significant effect of these two variables on the cell growth and chitin production. In optimum conditions, including pH?=?5.7 and inoculum size of 7.4%, the cell dry weight was 5.91?g/L and the amount of chitin production was 1.08?g/L with the productivity of 0.083?g/(L day). The produced chitin and chitosan were characterized using XRD and FTIR. Moreover, the antibacterial activity of the produced chitosan was investigated and compared with the commercial chitosan. The results showed that the produced chitin and chitosan had suitable quality and the Iranian G. lucidum would be a great source for safe and high-quality chitin and chitosan production.     

Exopolysaccharide biosynthesis and related enzyme activities of the medicinal fungus, Ganoderma lucidum, grown on lactose in a bioreactor

Exopolysaccharide (EPS) production and biosynthesis were studied in Ganoderma lucidum, a fungus used in traditional Chinese medicine, grown with lactose in a bioreactor. -Galactosidase activity, which implies the existence of a lactose permease system, was induced by lactose. Lactose feeding also increased -phosphoglucomutase activity and EPS accumulation but decreased phosphoglucose isomerase activity and lactate concentration in the culture broth. A maximum cell density of 22 g l^–1 and EPS at 1.25 g l^–1 were obtained in fed-batch bioreactor culture.     

Efficient transformation of the medicinal mushroomGanoderma lucidum

Ganoderma lucidum is a well-known and important medicinal mushroom, but its genetic modification has not been reported. We developed an efficient procedure for isolation and regeneration of protoplasts fromG. lucidum. To construct a vector for high-level expression of heterologous genes inG. lucidum, the 1.4-kb regulatory region of the glyceraldehyde-3-phosphate dehydrogenase gene (GPD) was isolated from the genomic DNA ofLentinus edodes, and theGPD promoter was fused to the β-glucuronidase (GUS) and bialaphos resistance (bar) genes. Using the resulting construct, p301-bG1, an efficient transformation system based on electroporation was established forG. lucidum. GUS expression was observed among transformants conferring bialaphos resistance, indicating that theL. edodes GPD promoter can be used for expression of exogenous genes inG. lucidum. We also studied green fluorescent protein (GFP) as another reporter for transformation ofG. lucidum. TheL. edodes GPD promoter was fused respectively to theGFP andbar genes, and the resulting construct, p301-bg, was introduced intoG. lucidum. StableGFP expression in transformants was detectable by fluorescence microscopy, suggesting the suitability ofGFP as a reporter system in transformation of this mushroom. This is the first report of an efficient transformation system forG. lucidum using different reporters, paving the way for genetic modification of this famous medicinal mushroom.     

Alternative methods for genetic transformation of Pseudozyma antarctica, a basidiomycetous yeast-like fungus

Electroporation and Agrobacterium tumefaciens-mediated transformation (ATMT) were adapted and optimized for genetic transformation of the basidiomycetous yeast-like fungus Pseudozyma antarctica as alternatives to the cumbersome PEG/CaCl₂-mediated transformation of protoplasts. Electroporation yielded 100–200 transformants per μg of DNA per 10⁸ cells after 3 days on selective medium. For its part, ATMT yielded 60–160 transformants per 10⁶ input cfu after 5–10 days on a selective medium. Transformants obtained from both methods showed stable hygromycin resistance and strong expression of green fluorescent protein. Analysis of integration events revealed a limited number of predominantly tandem insertions in the genome of transformants, an improvement over PEG/CaCl₂-mediated transformation. Both protocols relied on intact conidia of P. antarctica as starting material and thus eliminated the need for cell wall-degrading or weakening agents such as lytic enzymes or chemicals. Other advantages over protoplast transformation included higher yield of transformants and shorter recovery time of transformed colonies on selective medium.     

Isolation and characterization of alpha-glucosidase inhibitor from the fungus Ganoderma lucidum

An alpha-glucosidase inhibitor, SKG-3, was isolated from the fruiting bodies of Ganoderma lucidum and its physico-chemical properties were characterized. It was a highly specific and effective reversible inhibitor of alpha-glucosidase. It showed very potent inhibitory activity against alpha-glucosidase with an IC50 value of 4.6 micro g/ml, but no activity for any other glycosidases tested. Enzyme activity could be recovered upon dialysis, thus providing evidence for the reversibility of the inhibition. A Lineweaver-Burk plot indicated that the SKG-3 inhibition of alpha-glucosidase was competitive.     

Development of a simple and rapid Agrobacterium tumefaciens-mediated transformation system for the entomopathogenic fungus Metarhizium anisopliae var. acridum

AIMS: To examine the ability of Agrobacterium to attach to Metarhizium anisopliae var. acridum strain CG423 under co-cultivation and to develop an Agrobacterium-mediated method of gene delivery into strain CG423, a promising agent for biological control of grasshoppers. METHODS AND RESULTS: The co-cultivation of Agrobacterium tumefaciens and M. anisopliae var. acridum was analysed under scanning electron microscopy. We observed that Agrobacterium attached to and formed aggregates around Metarhizium conidia and germ tubes. We also observed the occurrence of fibril-like structures connecting neighbouring bacterial-fungal cells. The Agrobacterium-mediated transformation was applied using two binary vectors carrying a benomyl resistance gene as a selection marker. The efficiency of transformation was up to 53 transformants per 10(5) target conidia. High mitotic stability of the transformants (89-97%) was demonstrated after five successive transfers on non-selective media. Molecular analysis revealed the occurrence of high frequency of gene conversion. CONCLUSIONS: In our study, we report that A. tumefaciens strain AGL-1 attaches to and genetically transforms the entomopathogenic fungus Metarhizium anisopliae var. acridum. SIGNIFICANCE AND IMPACT OF THE STUDY: We report for the first time, the attachment of Agrobacterium to fungal cells opening new avenues for the study of this essential step of the T-DNA transfer process. Considering the efficiency of the transformation protocol herein described, this is a useful tool for gene disruption in M. anisopliae var. acridum.     

Enhancement of mycelial growth and polysaccharide production in Ganoderma lucidum (the Chinese medicinal fungus, `Lingzhi') by the addition of ethanol

Methanol, ethanol, 1-propanol and 2-propanol, at 1.5% (v/v), enhanced the growth and polysaccharide production of Ganoderma lucidum. Ethanol was the most effective at 1.5% (v/v) for increasing the biomass production, however, the maximal polysaccharide concentration was produced with 2% (v/v) ethanol in the medium. There was no new polysaccharide component produced by the addition of ethanol.     

Anti-inflammatory and anti-tumor-promoting effects of triterpene acids and sterols from the fungus Ganoderma lucidum

A series of lanostane-type triterpene acids, including eleven lucidenic acids (3, 4, 9, 10, 13-19) and six ganoderic acids (20-22, 24, 26, 27), as well as six sterols (28-33), all isolated from the fruiting bodies of the fungus Ganoderma lucidum, were examined for their inhibitory effects on the induction of Epstein-Barr virus early antigen (EBV-EA) by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, a known primary screening test for anti-tumor promoters. All of the compounds tested, except for ganolactone (27) and three sterols (29-31), showed potent inhibitory effects on EBV-EA induction, with IC(50) values of 235-370 mol ratio/32 pmol TPA. In addition, nine lucidenic acids (1, 2, 5-8, 11, 12, 18) and four ganoderic acids (20, 23-25) were found to inhibit TPA-induced inflammation (1 microg/ear) in mice, with ID(50) values of 0.07-0.39 mg per ear. Further, 20-hydroxylucidenic acid N (18) exhibited inhibitory effects on skin-tumor promotion in an in vivo two-stage mouse-skin carcinogenesis test based on 7,12-dimethylbenz[a]anthracene (DMBA) as initiator, and with TPA as promoter.     

A distinctive ribonuclease from fresh fruiting bodies of the medicinal mushroom Ganoderma lucidum

A ribonuclease with an N-terminal sequence distinct from other mushroom ribonucleases was isolated from fresh fruiting bodies of the medicinal mushroom Ganoderma lucidum. The ribonuclease was adsorbed on DEAE-cellulose and Q-Sepharose, and unadsorbed on CM-Sepharose. It possessed a molecular mass of 42 kDa as judged by gel filtration by fast protein liquid chromatography on Superdex 75 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its molecular mass was similar to that of straw mushroom ribonuclease but much higher compared with those of other mushroom ribonucleases. The ribonuclease was unique among mushroom ribonucleases in that it exhibited the highest potency toward poly(U), followed by poly(A). Its activity toward poly(G) and poly(C) was about one-half of that toward poly(A) and one-quarter of that toward poly(U). A pH of 4.0 and a temperature of 60 degrees C were required for optimal activity of the enzyme. The optimum pH was low compared with those reported for other mushroom ribonucleases.     

Development of efficient strain of Ganoderma lucidum for biological stripping of cotton fabric dyed Reactive Blue 21

One of the most common dyeing problems of textile industries is uneven and faulty dyeing over the finished quality of fabrics due to different reasons. These problems are usually tackled through chemical degradation in which uneven and faulty dye is removed from the surface of fiber but fabric quality is compromised. Chemical process also reduces the strength of the fabric and durability of textile material by reduction in reactive dye ability. The fabric cannot be reused due to the reduced strength. To overcome above mentioned problem, biological method of stripping in which enzymes produced by different micro-organisms are used. This process has no harmful effect on the fabric and is safe for environment. In this research work reactive blue 21 dye with 0.5, 2 and 4% shade strengths was used to dye cotton fabric. The Ganoderma lucidum fungal strains were mutated by UV mutagen, and five were selected for further processing. These mutant strains were grown at temperature ranges (20 °C to 40 °C); pH(3–5); inoculum size(1–5 mL) and fermentation time (3–15 days) . The required nutrients media to produce the ligninolytic enzymes was added to the flask. The strain which gave the fast decolourization results was selected for further optimization. Optimization was done by observing the variables: incubation time 12 days, pH 4, temperature 30 °C, and inoculum size 3 mL by applying Response Surface Methodology (RSM) in Central Composite Design (CCD). During the process of fabric color stripping, the enzyme assay revealed that the respective mutant UV-60 strain produced active enzymes with their V_max, Mnp (427U/mL), LiP (785U/mL), and Lac (75 U/mL) enzymes decolorized 89% of the dye which is 25% more than the parent strain and also the production of enzyme is Mnp (344U/mL), LiP (693U/mL), and Lac (59 U/mL) enzymes which is lower than mutant strain.     

Scale-up of a liquid static culture process for hyperproduction of ganoderic acid by the medicinal mushroom Ganoderma lucidum

Scale-up of a liquid static culture process was studied for hyperproduction of ganoderic acid (GA) by a famous Chinese traditional medicinal mushroom, Ganoderma lucidum. Initial volumetric oxygen transfer coefficient (K(L)a) and area of liquid surface per liquid volume (A(s)) were identified as key factors affecting cell growth and GA accumulation in liquid static cultures of G. lucidum, on the basis of which a multilayer static bioreactor was designed. At a low initial K(L)a level of 2.1 h(-1), a thick layer of white mycelia was formed on the liquid surface, and an optimal production of total GA (i.e., GA production in the liquid and on the liquid surface) was obtained. Both the formation of white mycelia and production of GA on the liquid surface were enhanced with an increase of A(s) within the range as investigated (0.24-1.53 cm(2)/mL). At an A(s) value of 0.90 cm(2)/mL, the total GA production reached maximum. A successful scale-up from a 20-mL static T-flask to a 7.5-L three-layer static bioreactor was achieved based on initial K(L)a. The maximum biomass (20.8 +/- 0.1 g DW/L), GA content (4.96 +/- 0.13 mg/100 mg DW), and total GA production (976 +/- 35 mg/L) were attained in static bioreactors. Not only GA content but also its production obtained in this work were the highest ever reported.     

Performance analyses of a pH-shift and DOT-shift integrated fed-batch fermentation process for the production of ganoderic acid and Ganoderma polysaccharides by medicinal mushroom Ganoderma lucidum

Investigations on Ganoderma lucidum fermentation suggested that the responses of the cell growth and metabolites biosynthesis to pH and dissolved oxygen tension (DOT) were different. The ganoderic acid (GA) production of 321.6 mg/L was obtained in the pH-shift culture by combining a 4-day culture at pH 3.0 with the following 6-day culture at pH 4.5, which was higher by 45% and 300% compared with the culture at pH 3.0 and 4.5, respectively. The GA production of 487.1 mg/L was achieved in the DOT-shift culture by combining a 6-day culture at 25% of DOT with a following 6-day culture at 10% of DOT, which was higher by 43% and 230% compared with the culture at 25% and 10% of DOT, respectively. A fed-batch fermentation process by combining the above-mentioned pH-shift and DOT-shift strategies resulted in a significant synergistic enhancement of GA accumulation up to 754.6 mg/L, which is the highest reported in the submerged fermentation of G. lucidum in stirred-tank bioreactor.     

Development of strain-specific SCAR markers for authentication of Ganoderma lucidum

In this study we report the application of sequence-characterized amplified region (SCAR) markers in Ganoderma lucidum for strain identification, the first such study in this medicinal mushroom. One fragment unique to strain No. 9 was identified by inter-simple sequence repeats (ISSR), and then sequenced. Based on the specific fragment, one SCAR primer pair designated as GL₆₁₂F and GL₆₁₂R was designed to amplify a 612-bp DNA fragment within the sequenced region. Diagnostic PCR was performed using the primer pair. The results showed that this SCAR marker can clearly distinguish strain No. 9 from other related Ganoderma lucidum strains. Our data provided the foundation for a precise and rapid PCR-based strain-diagnostic system for Ganoderma lucidum.