Analysis of codon usage patterns in Polyporus umbellatus based on transcriptome data / 药学学报

We obtained 332 coding sequences from the Polyporus umbellatus transcriptome based on the BLASTx and ESTScan analyses. The codon usage patterns of P. umbellatus were calculated and statistically analyzed using CodonW. The results showed that the average GC content of genes was 53.57% and the average GC3 content was 57.98%, suggesting that genes favored codons ending with G or C. The effective number of codons (ENC) value range from 38.46 to 61, which indicates that these genes have low codon usage bias. The neutrality plot and ENC-plot analysis revealed that many factors such as mutation and selective pressure play an important role in shaping codon usage bias in P. umbellatus genes. Twenty-two optimal codons were identified as being biased toward codons ending with G or C using the high expression superior codon analysis method. This study will lay a foundation for future research on genetic engineering and molecular evolution in P. umbellatus.

Molecular cloning and prokaryotic expression of a type II ribosome inactivating protein from Polyporus umbellatus / 药学学报

A type Ⅱ ribosome inactivating protein (RIP) gene was cloned from Polyporus umbellatus sclerotia by RT-PCR method. The full open reading frame cDNA sequence of this gene was 873 bp in length and encoded a 290-aa protein with a molecular weight of 32.33 kDa and an isoelectric point of 5.58. Multiple sequence alignment revealed that the deduced amino acids possessed conserved domains of RICIN superfamily protein. A neighbor joining phylogenetic analysis suggests that PuRIP was closely related to RIP in Marasmius oreades. Real time PCR results showed that this gene expressed in all tested tissues of P. umbellatus. Meanwhile, the expression of this gene was significantly up-regulated in the part infected by Armillaria mellea. This result suggested that this PuRIP might played important role with potential biotic stress tolerance of P. umbellatus. Otherwise, we successfully constructed the pET15b-PuRIP plasmid, produced and purified the His-PuRIP fusion protein, which would provide the basic material for polyclonal antibody preparation and gene function research.

Molecular cloning and characterization of two kind of heat-shock protein gene from Polyporus umbellatus / 中国中药杂志

With RT-PCR approaches, the full-length cDNA of two heat shock protein genes were cloned from total RNA of the Polyporus umbellatus sclerotium. The full open reading frame cDNA sequence of the Hsp90 was 2 091 bp, encoding 696 amino acid residues with a predicted molecular mass of 78.9 kDa. The full open reading frame cDNA sequence of the Hsp70 was 1 944 bp, encoding 647 amino acid residues with a predicted molecular mass of 70.5 kDa. The Hsp90 and Hsp70 protein contained the conservative structure domain, respectively. Phylogenetic analysis showed that Hsp90 and Hsp90 from Trametes versicolor were clustered into one group, Hsp70 and Hsp70 from Fistulina hepatica were clustered into one group. Real-time PCR analysis showed that, the expression of Hsp90 and Hsp70 in the infected part by Amillariella mellea was upregulated. The expression profiling of Hsp90 and Hsp70 showed same patterns underbiotic stress. The results indicate that these two genes may play an important role in response to Amillariella mellea infection.

Habitat suitability assessment of medicinal Polyporus umbellatusin China based on Maxent modeling / 中国中药杂志

Geographic distribution of Polyporus umbellatus was predicted by using distribution records. Based on 42 distribution records from 12 provinces and bioclimatic data (1950-2000), georaphic distribution of P. umbellatus was modeled using Maxent. The results showed thatthe Receiver Operating Characteristic (ROC) curve analysis method was used to assess the accuracy of MAXENT model and the area under ROC curve (AUC) value of MAXENT was 0. 960 which suggested that the result of assessment was dependable. The geographic distribution pattern of were divided into three distribution block based on distribution values of 0.5-0.8: small area of Heilongjiang, Jilin, Liaoning and Hebei province, the board area of Yunnan, Guizhou and Sichuan, the southeast area of Tibet and the most area of Shanxi and Shannxi, the southeast board area of Shannxi, Gansu and Ningxia. Jackknife Test showed that average precipitation in warm seasons had the greatest contribution to the distribution gain of P. umbellatus, followed by mean temperature of driest quarter and annual mean temperature. The object suggests the potential distribution areasof P. umbellatus which is useful for the habitat conservation and introduction of P. umbellatus.

Molecular cloning and characterization of four small GTPase genes from medicinal fungus Polyporus umbellatus / 药学学报

Four small GTPase genes which may be relative to sclerotial development were firstly cloned from medicinal fungus Polyporus umbellatus using rapid amplification of cDNA end PCR (RACE) method. The results showed that full-length cDNA of PuRhoA was 698 bp contained 585 bp ORF, which was predicted to encode a 194 amino acid protein with a molecular weight of 21.75 kD with an isoelectric point (pI) of 6.44; the full length cDNA of PuRhoA2 was 837 bp in length and encoded a 194 amino acid protein with a molecular weight of 21.75 kD and an isoelectric point (pI) of 6.33; the full length cDNA of Puypt1 was 896 bp in length and encoded a 204-aa protein with a molecular weight of 22.556 kD and an isoelectric point (pI) of 5.75; the full length cDNA of PuRas was 803 bp in length and encoded a 212-aa protein with a molecular weight of 23.821 kD and an isoelectric point (pI) of 5.2. There are fani acyl transferase enzyme catalytic site and myrcene-transferase enzyme catalytic site in PuRhoA1 while the PuRhoA2 only possess myrcene-transferase enzyme catalytic site. Puypt1 contains the Rab1-Ypt1 conserved domain of small GTPase family and PuRas contains the fani acyl transferase enzyme catalytic site. According to the phylogenetic analysis all these four small GTPase clustered with basidiomycete group. Quantitative real-time PCR analysis revealed that Puypt1, PuRas and PuRhoA1 transcripts were significantly higher in the beginning of sclerotial formation than that in the mycelia, whereas the transcripts levels of PuRhoA2 gene were particularly lower in sclerotia than that in mycelia, suggesting that these four genes might be involved in P umbellatus selerotial development.

Physicochemical properties of medicinal fungus Polyporus umbellatus sclerotial exudate / 中国中药杂志

This study was conducted to investigate the physicochemical properties of Polyporus umbellatus sclerotial exudate. Morphological characteristics of the sclerotia and its exudate were observed during different stages of sclerotial formation. The pH of the exudate was detected at different time during cultivation. A phenol-sulfuric acid method was employed to determine the polysaccharide content of P. umbellatus sclerotial exudate during cultivating time. Additionally, the protein content was measured by means of BCA protein assay. Furthermore, CAT content was detected using ultraviolet absorption method. That the protein content of the exudate and CAT specific activity rose gradually during the passage of the cultivating time indicated a high level of oxidative stress during P. umbellatus sclerotial exudate formation. The results showed that the pH of the exudate increased gradually and then dropped down during sclerotial formation. That the pH of the exudate maintained the acidity state during the cultivation indirectly indicated that acidic environment would help sclerotial formation. The exudate produced gradually and was absorbed by the sclerotia itself.

Expression of recombinant human kallistatin in Pichia pastoris by high density cell culture, and its purification and characterization / 药学学报

Kallistatin (Kal) is a negative acute phase endogenous protein which can inhibit tumor angiogenesis, growth and metastasis effectively. To express and purify recombinant human kallistatin (rHKal), and characterize its biological activity, P. pastoris was transformed with pPIC9-Kal/GS115 (His4) to express rHKal. The fermentation was carried out in a 7.5 L bioreactor with high density cell culture. 1%-2% methanol was added to the medium to induce the expression of rHKal. The secretion was purified with phenyl sepharose, G-25 sepharose, heparin sepharose and Sephacryl S-100 chromatography. The biological activity of purified bulk rHKal on HUVEC was evaluated with MTT and tube formation assays. The final expression of rHKal in the supernatant reached 50 mg x L(-1), the purity of bulk rHKal after purification was above 98%. A dose-dependent inhibition of rHKal on HUVEC proliferation was observed, however, a U-shaped dose-response curve of rHKal on capillary formation of HUVEC was revealed. The described protocol provides an effective means for preparing rHKal that could be used for anti-angiogenesis therapy in the future.

M cell in vitro model and its application in oral delivery of macromolecular drugs / 药学学报

The oral administration of bioactive macromolecular drugs such as proteins, peptides and nucleic acids represents unprecedented challenges from the drug delivery point of view. One key consideration is how to overcome the gastrointestinal tract absorption barrier. Recent studies suggest that microfold cell (M cell), a kind of specialized antigen-sampling epithelial cell which is characterized by a high endocytic rate and low degradation ability, may play an important role in macromolecule oral absorption. The development of an in vitro M cell coculture system and its modified models greatly advanced the study of M cells and the development of oral delivery system for macromolecular drugs. The special structure, function and formation characteristics, and biomarkers of M cell are summarized in this review. The applications of in vitro M cell models in developing oral delivery system ofbioactive macromolecular drugs are discussed.