Molecular Cloning and Expression of Polyphenoloxidase Genes from the Mushroom, Agaricus bisporus

The polyphenoloxidase（PPO） is the key enzyme considered to be responsible for mushroom browning.By using homology cloning and rapid amplification of cDNA ends（RACE）,two new PPO genes and the corresponding cDNA were identified from the fruit bodies of Agaricus bisporus（AbPPO3 and AbPPO4,GenBank accession nos.GU936494 and GU936493,respectively）.The genomic DNA sequences of AbPPO3 and AbPPO4 are 2 080 and 2 189 bp in length,respectively,encoding putative polypeptides of approximately 66 and 68 kDa.The deduced amino acid sequences show characteristic features of two copper-binding domains conserved in the type III copper proteins including fungal polyphenol oxidases.Sequence comparisons indicate that AbPPO3 and AbPPO4 present 55.3% similarity to each other（48% identity）.We also obtained more than 1.5-kb long sequences upstream of the start codon of the AbPPO3 and AbPPO4 and recognized them as their respective putative promoters.Analyses of the two PPO promoter regions show that they contain abundant cis-acting elements which are probably responsible for anaerobic induction,light,wound,stress,and auxin response.Semi-quantitative RT-PCR results indicate that AbPPO3 and AbPPO4 were highly expressed in the mature fruit bodies and up-regulated after 2-d storage of mushroom.These results suggest that AbPPO3 and AbPPO4 may play roles in A.bisporus browning and pigmentation during development and postharvest storage and the elements in promoters may act as regulatory elements for the inducible expression of AbPPO3 and AbPPO4.The successful cloning and expression analysis of AbPPO3 and AbPPO4 warrant a further investigation on the structure and function of A.bisporus PPO which points to the possible targets for genetic manipulation.

Screening on Chemicals for Preventing Mycogone peniciosa Magn in Agaricus bisporus

[ Objective ] The aim was to screen out chemicals with good control effect against Mycogone peniciosa Magn in Agaricus bisporus. [ Method ] M. peniciosa ofA. b/sporus was taken as the detection bacteria, and nine kinds of chemicals were conducted plate efficacy test in the laboratory. Mushroom house validation was carried out for the screened chemicals with strong inhibition to M. peniciosa. [ Result] Nine kinds of chemicals had obvious difference in control effects on M. peniciosa and effects on growth ofA. bisporus; 2 400 and 3 200 times dilution of 78% Boer MZ WP and 2 400 times dilution of 69% Fulishuang WP after casing material processing had good control effects on M. peniciosa and had no apparent adverse effects on mycelial growth and fruiting development of A. bisporus. [ Conclusion] The 2 400 and 3 200 times dilution of 78% Boer MZ WP and 2 400 times dilution of 69% Fulishuang WP are worth popularizing.

Two Routes to Produce Chitosan from Agaricus bisporus

Two methods were used to produce chitosan by deacetylation of chitin which was extracted from Agaricus bisporus stipes.The first one gives chitosan 1 with low yield of 2.5%,degree of acetylation(DA)of 4%,molecular weight(MW)of 2.973×10^(5)(g/mol).The second route produces chitosan 2 with higher yield of 41%,degree of acetylation(DA)of 17.23%,molecular weight(MW)of 2.939×10^(5)(g/mol).Both chitosans were characterized by XRD,FTIR,^(1)H-NMR spectroscopy nuclear magnetic resonance of proton.The molecular weight(MW)was determined by size exclusion chromatography(SEC).Thermal analysis shows that both chitosans have moisture content lower than 10%.However chitosan 2 has the less ash%which is the quality grade for chitosan medical applications.Accordingly,fungal chitosan 2 could have potential medical and agricultural applications.

Morphological Features of Agaricus bisporus and Indoor Toxicity Test of Chemicals

Through separating and purifying diseased mushrooms infected by Mycogone perniciosa in Gaochun Area, Nanjing City, morphological features of the bacteria were identified, and toxicity of the bacterial strains was tested. The results showed that five bactericides in the experiment had obvious inhibitory effect on the growth of M. perniciosa, especially 50% Prochloraz manganese chloride complex WP 5 g/L had the best efficiency.

Preliminary Study on Mixed Use of Agaricus bisporus Residue and Microbial Agent to Control Cucumber Root-knot Nematode

Single or mixed use ofAgaricus bisporus residue and microbial agent had better control effect on cucumber root-knot nematode disease in greenhouse. The results showed that the control effect of single use of A. b/sporus residue was 32.9% - 34.7%, and the yield increasing rate was 2.1% - 8.7% ; the control effect of mixed use ofA. b/sporus residue and microbial agent was 59. 1% - 63. 6%, and yield increasing rate was 2.6% - 3.5%. The experimental dose had no ad- verse effects on soil physical and chemical properties. The mixed use of A. b/sporus residue and microbial agent was one of the effective ways to control root-knot nematode disease.

Accumulation Characteristics and Resistance to Heavy Metal Contamination of Agaricus bisporus Varieties in Shanxi Province,China

In order to evaluate the accumulation characteristics of heavy metals in the cultivars of Agaricus bisporus in Shanxi Province and to select the varieties with high resistances to heavy metal pollution, atomic absorption spectrophotometer and the atomic fluorescence spectrophotometer were used as the determination methods to compare the heavy metal contents and accumulation characteristics of 6 different varieties. The results showed that 3 heavy metal elements （lead, chromium and cadmium） were tested in the 6 varieties of A. bisporus , all of which were contaminated by heavy metals, but basically no beyond the national standards for food safety. In general, these varieties had less quality risk and could be eaten safely. The accumulation characteristics of heavy metals in these varieties were analyzed, and the varieties were screened according to the resistance to heavy metals pollution. The results showed that variety No. 1 and No. 6 were the varieties with strong comprehensive resistance to the 3 types of heavy metal pollution, and variety No. 3 was a species with weak comprehensive ability in resisting heavy metal pollution.

Study on the Accumulation of Heavy Metals in Varieties of Agaricus bisporus

The accumulation characteristics and resistance to heavy metal pollution of six varieties of Agar/cus b/spoms were studied. The results showed that arsenic, mercury and cadmium content could be detected in the six varieties, and all of the varieties were contaminated by heavy metals ,but they did not exceed the limits in the national standards for food safety. These varieties had a low quality risk and can be eaten safely. Varie-ties 1 and 6 were strongly resistant to the three kinds of heavy metals, while variety 4 was weakly resistant to heavy metal pollution.

Use of Agaricus bisporus mushroom in beef burgers:antioxidant,flavor enhancer and fat replacing potential

This study aimed to evaluate the potential use of Agaricus bisporus mushroom as a natural antioxidant,fat/salt substitute and flavor enhancer in beef burger.Ten treatments were considered using a fractional factorial design(salt[0.5,1.25 and 2.0%],fat[10,15 and 20%]and mushroom content[0,15 and 30%]).Treatments were characterized by instrumental and sensory measurements.The statistical design indicated that fat content had little influence on the results.The principal component analysis showed that the incorporation of mushrooms and salt modified the texture,moisture and water activity.Oxidative stability decreased as the salt content increased,at a low-fat content.Finally,the sensory profile was affected by the mushroom and salt contents,with the fat content exerting the least influence.Therefore,mushroom incorporation in beef burger may be a feasible strategy to reduce the fat content of beef burgers.

Removal of Zn2＋ from aqueous solution by biomass of Agaricus bisporus

Abstract Biosorption of Zn2＋ from aqueous solutions by biomass of Agaricus bisporus was investigated. The removal rates of Zn2＋ by A. parameters （e.g., solution pH, initial Zn2＋ concentration） were A. bisporus＇s biosorption by bisporus under different bio-sorbent dosage and studied. The inhibition of anionic ligands EDTA （Ethylene Diamine Tetraacetic Acid）, acetate and citrate） implied that EDTA and citrate might be used as eluting reagents. Regular and simultaneous solution pH change and light metal ions release after biosorption indicated that an ion exchange mechanism was involved. From FT-IR （Fourier Transform Infrared） spectroscopy, the main functional groups participated in biosorption were found. Biosorption of Znz＋ byd. bisporus could be well described by the Freundlich and Langmuir models. In conclusion, the biomass of A. bisporus showed high potential for the treatment of wastewater containing Zn2＋.

Design and experiment of the environment control system for the industrialized production of Agaricus bisporus

Environment parameters are the main factors affecting the growth and development of Agaricus bisporus.Because of the requirements of environmental conditions for high-efficiency industrialized production of Agaricus bisporus,equipments for environment control were developed.Based on the variable operating equipment,a multi-factor fuzzy controller was designed to realize the comprehensive control of ambient temperature,humidity,CO2 concentration,and the temperature and moisture of the compost.The test results showed that the temperature control error was less than±0.5°C and the response speed was more than 0.5°C/h;The control error of ambient humidity was less than±2%RH,and the response speed was more than 9%RH per hour;The moistures at different points in compost ranged from 50%to 70%with a standard deviation of 4.04.The control accuracy of environmental CO2 concentration was within 200μmol/mol.The overall performance of the control system was stable and reliable,which could meet the requirements of environment factors for the growth of Agaricus bisporus.The system can provide technical support and reference for the automatic and precise control of the environment during the industrialized production of Agaricus bisporus.

Effect of precooling temperature on physiological quality of cold stored Agaricus bisporus

Effect of precooling temperatures(2℃,6℃,10℃and 14℃)on the physiological quality of postharvest Agaricus bisporus during cold storage was investigated.After six hours’precooling,Agaricus bisporus was stored at 3℃and sampled on day 3,6 and 9,respectively,for physiological quality analysis.Results showed that physiological quality of the Agaricus bisporus increased with the decrease of precooling temperature in the range of 2-14℃.Precooling at 2℃before cold storage had a positive impact on the storage quality of Agaricus bisporus.The decrease of hardness,whiteness and pH value was delayed,while the increase of cell membrane permeability and PPO and POD activities was restrained.Whiteness value of the Agaricus bisporus precooled at 2℃was above 80 on day 9,which means it was still acceptable,but the Agaricus bisporus precooled at 6℃and 10℃lost their commercial values.

The effects of dietary supplementation with mushroom or selenium enriched mushroom powders on the growth performance and intestinal health of post-weaned pigs

Background There is an urgent need to identify natural bioactive compounds that can enhance gastrointestinal health and promote pig growth performance in the absence of pharmacological levels of zinc oxide(ZnO).The objectives of this study were to:1)compare the effects of mushroom powder supplemented with inorganic selenium(inSeMP)to mushroom powder enriched with organic selenium(orgSeMP)to pharmacological levels of ZnO on growth performance and faecal scores(FS)for the first 21 d post-weaning(Period 1);and 2)compare the molecular and microbial effects of inSeMP and orgSeMP in these pigs on d 39 post-weaning(Period 2).Methods In Period 1,pigs(3 pigs/pen;8 pens/treatment)were assigned to:(1)basal diet(control);(2)basal diet+zinc oxide(ZnO)(3100 mg/kg d 1–14,1550 mg/kg d 15–21);(3)basal diet+mushroom powder supplemented with inorganic selenium(inSeMP)containing selenium(selenite)content of 0.3 mg/kg feed;(4)basal diet+mushroom powder enriched with organic selenium(orgSeMP)containing selenium(selenocysteine)content of 0.3 mg/kg feed.Mushroom powders were included at 6.5 g/kg of feed.Results In Period 1,there was no effect of diets on average daily gain(ADG)and gain:feed(G:F)ratio(P>0.05).The orgSeMP supplemented pigs had a lower average daily feed intake(ADFI)compared to all other groups(P<0.05).The ZnO supplemented pigs had reduced FS compared to the basal and mushroom group,while the orgSeMP supplemented pigs had lower FS compared to the basal group during the 21 d experimental period(P<0.05).In Period 2,there was no effect of diets on ADFI,ADG and G:F ratio(P>0.05).The orgSeMP supplementation increased the caecal abundance of bacterial members of the Firmicutes and Bacteroidetes phylum,including Lactobacillus,Agathobacter,Roseburia,and Prevotella and decreased the abundance of Sporobacter compared to the basal group,while inSeMP increased the caecal abundance of Prevotella and decreased the caecal abundance of Sporobacter compared to the basal group(P<0.05).Dietary supplementation with inSeMP increased expression of TLR4 and anti-inflammatory cytokine gene IL10 and decreased nutrient transporter gene FABP2 compared to the orgSeMP group(P<0.05).Conclusion OrgSeMP is a novel and sustainable way to incorporate selenium andβ-glucans into the diet of weaned pigs whilst improving FS and modulating the caecal microbiota.

烟秸秆栽培双孢蘑菇的技术研究

以烟草秸秆为试材,利用烟秸秆替代玉米秸秆、玉米芯等原料栽培双孢蘑菇(Agaricus bisporus),对比了3种不同原料对双孢菇产量及单品重的影响。结果表明,利用烟秸秆栽培的双孢蘑菇出菇集中,第一潮菇占总产量的60%以上;前三潮菇产量达18 kg/m^(2)以上;与玉米秸秆相比,用烟秸秆栽培双孢蘑菇的总产量和平均单品重显著增加;与玉米芯相比较,用烟草秸秆栽培双孢蘑菇的总产量和平均单品重无显著差异。

双孢蘑菇培养料在不同栽培模式下的生产应用效果研究

通过对生产好的优质隧道二次发酵料进行打包处理培养,与传统发酵料直接上架培养2种栽培模式进行对比,在相同的生产栽培管理条件下,观察分析对双孢蘑菇(Agaricus bisporus)的菌丝长势、出菇期、产量和效益的影响^([2-4])。结果表明,采用传统的发酵料直接上架的栽培模式,菌种前期发菌速度和长势均比打包料栽培模式的强,出菇期提前4 d;从后期产量和效益上看,表现也优于打包料的栽培模式。但是打包料具有省工、抗污染、便于长距离运输等优点,适合公司+农户的经营模式,对下一步优质、高效的双孢蘑菇打包料的应用推广提供一定的理论依据。