Cdc42GAP deficiency contributes to the Alzheimer's disease phenotype.

Alzheimer's disease, the most common cause of dementia, is a chronic degenerative disease with typical pathological features of extracellular senile plaques and intracellular neurofibrillary tangles and a significant decrease in the density of neuronal dendritic spines. Cdc42 is a member of the small G protein family that plays an important role in regulating synaptic plasticity and is regulated by Cdc42GAP, which switches Cdc42 from active GTP-bound to inactive GDP-bound states regulating downstream pathways via effector proteins. However, few studies have focused on Cdc42 in the progression of Alzheimer's disease. In a heterozygous Cdc42GAP mouse model that exhibited elevated Cdc42-GTPase activity accompanied by increased Cdc42-PAK1-cofilin signalling, we found impairments in cognitive behaviours, neuron senescence, synaptic loss with depolymerization of F-actin and the pathological phenotypes of Alzheimer's disease, including phosphorylated tau (p-T231, AT8), along with increased soluble and insoluble Aß1-42 and Aß1-40, which are consistent with typical Alzheimer's disease mice. Interestingly, these impairments increased significantly with age. Furthermore, the results of quantitative phosphoproteomic analysis of the hippocampus of 11-month-old GAP mice suggested that Cdc42GAP deficiency induces and accelerates Alzheimer's disease-like phenotypes through activation of GSK-3ß by dephosphorylation at Ser9, Ser389 and/or phosphorylation at Tyr216. In addition, overexpression of dominant-negative Cdc42 in the primary hippocampal and cortical neurons of heterozygous Cdc42GAP mice reversed synaptic loss and tau hyperphosphorylation. Importantly, the Cdc42 signalling pathway, Aß1-42, Aß1-40 and GSK-3ß activity were increased in the cortical sections of Alzheimer's disease patients compared with those in healthy controls. Together, these data indicated that Cdc42GAP is involved in regulating Alzheimer's disease-like phenotypes such as cognitive deficits, dendritic spine loss, phosphorylated tau (p-T231, AT8) and increased soluble and insoluble Aß1-42 and Aß1-40, possibly through the activation of GSK-3ß, and these impairments increased significantly with age. Thus, we provide the first evidence that Cdc42 is involved in the progression of Alzheimer's disease-like phenotypes, which may provide new targets for Alzheimer's disease treatment.

Characterization and expression pattern analysis of pheromone receptor-like genes in Winter Mushroom Flammulina filiformis.

Pheromone receptor-like genes (PRLGs) belong to the G protein-coupled receptors (GPCRs) family that interacts with biotic and abiotic stimulants and transmits signals to intracellular downstream pathways in eukaryotic cells. In this study, we investigated the structure and expressions patterns of PRLGs in Winter Mushroom Flammulina filiformis. Based on the alignment analysis, the structure of PRLGs was found conserved in F. filiformis strains expect few single-nucleotide polymorphism (SNP) sites. Six PRLGs were found at five different unlinked loci, scattered in the genomes of F. filiformis strains. These genes contain 2-5 introns; however, the introns were not found in the same relative positions regarding the encoded protein sequences in tested strains of F. filiformis. Three conserved motifs were identified in peptides structures of PRLGs, however, FfSte3.s6 contained only two types, suggests its difference in evolution and function. We have further analyzed the expression patterns of each PRLGs in different developmental stages of the fruiting body in F. filiformis by quantitative real-time polymerase chain reaction (qRT-PCR). The results exhibited expression variation of PRLGs at different developmental stages of the F. filiformis. Especially, FfSte3.s1 and FfSte3.s2 exhibited maximum expression level in mycelia stage. Other PRLGs exhibited high expression level in fruiting body stages. This study suggests that PRLGs could be vital genes involving in fruiting body development in F. filiformis. However, further studies could be performed to reveal their specific functional pathways in the fruiting body development.

Comparison of physicochemical and biochemical properties of natural and arginine-modified melanin from medicinal mushroom Ganoderma lucidum.

Melanin is a hydrophobic biomolecule produced widely in fungi. Compared with other fungi, health benefits have been associated with medicinal mushrooms, which may provide an excellent source of natural melanin. Nevertheless, the hydrophobicity of melanin may limit its applications. Consequently, the present study was carried out on isolation of melanin from the medicinal mushroom Ganoderma lucidum (GLM) and modification with arginine to improve its solubility. The physicochemical and biochemical properties of melanin were evaluated including structural characterization, solubility, stability, antioxidant activities, and inhibitory effect on pancreatic lipase activity. Arginine-modified melanin showed better solubility, higher color value, stronger antioxidant activity, and stronger inhibitory effect on pancreatic lipase activity in vitro than GLM. In addition, both have good stability in the dark and natural light. These results opened possibilities for providing an excellent source of natural melanin in health food or food additives fields.

Biochemical characteristics of a novel protease from the basidiomycete Amanita virgineoides.

The characterization of a novel protease from Amanita virgineoides is described. The A. virgineoides protease was purified to homogeneity using Q-Sepharose, carboxymethyl-cellulose, diethylaminoethyl-cellulose, and a gel filtration step on Superdex 75. The molecular mass of the purified protease was estimated to be 16.6 kDa. The protease was purified 32.1-fold, and its specific activity was 301.4 U/mg. The optimum pH was 4.0, and the optimum temperature was 50 °C. Kinetic constants (Km , Vmax ) were determined under the optimum reaction conditions, with Km and Vmax , being 3.74 mg/mL and 9.98 µg mL-1 Min-1 , respectively. The activity of the protease was curtailed by Cu2+ , Pb2+ , Fe3+ , Cd2+ , and Hg2+ ions but enhanced by Mg2+ , Ca2+ , and K+ ions at low concentrations. The protease activity was adversely affected by ethylene diamine tetraacetic acid, suggesting that it is a metalloprotease. Four peptide sequences were obtained from liquid chromatography-tandem mass spectrometry, including KQALSGIR, TIAMDGTEGLVR, VALTGLTVAEYFR, and AGAGSATLSMAYAGAR, which showed 86%, 64%, 60%, and 75% identity with peptides of Hypsizygus marmoreus, Dacryopinax sp. DJM-731 SS1, Trametes versicolor FP-101664 SS1, and Paxillus involutus ATCC 200175, respectively. The newly isolated protease showed good hydrolytic activity and biochemical characteristics, which expanded the knowledge of biologically active proteins and provided further insight on this poisonous fungus.

Cocaine-induced synaptic structural modification is differentially regulated by dopamine D1 and D3 receptors-mediated signaling pathways.

Synaptic plasticity plays a critical role in cocaine addiction. The dopamine D1 and D3 receptors differentially regulate the cocaine-induced gene expression, structural remodeling and behavioral response. However, how these two receptors coordinately mediate the ultra-structural changes of synapses after cocaine exposure and whether these changes are behaviorally relevant are still not clear. Here, using quantitative electron microscopy, we show that D1 and D3 receptors have distinct roles in regulating cocaine-induced ultra-structural changes of synapses in the nucleus accumbens and caudoputamen. Pre-treatment of cocaine-treated mice with D3 receptor antagonist NGB2904 resulted in an increase in the ratio of total and asymmetric synapse to neuron and in the length of postsynaptic densities, compared with cocaine treatment alone. In contrast, pre-treatment of cocaine-treated mice with D1 receptor antagonist SCH23390 caused a reduction in synapse-to-neuron ratio and in postsynaptic densities length. Similarly, NGB2904 and SCH23390 showed opposite/differential effects on cocaine-induced structural plasticity, conditioned place preference and locomotor activity and signaling activation, including the activation of ERK, CREB and NR1 and the expression of c-fos and Cdk5. Therefore, we provide direct electron microscopy evidence that dopamine D1 and D3 receptors reciprocally regulate the ultra-structural changes of synapses following chronic exposure to cocaine. In addition, our data suggest that D1 and D3 receptors may regulate cocaine-induced ultra-structural changes and behavior responses by impact on structural plasticity and signaling transduction.

Characterization of Polysaccharides with Antioxidant and Hepatoprotective Activities from the Edible Mushroom Oudemansiella radicata.

The preliminary structure, in vitro antioxidant and in vivo hepatoprotective activities of water-soluble polysaccharides (ORWP) and alkali-soluble polysaccharides (ORAP), prepared from the mushroom Oudemansiella radicata, were investigated. Both ORWP and ORAP were heteropolysaccharides with mannose, glucose and galactose being the main monosaccharide components. Regarding the antioxidant activities, ORWP and ORAP showed effective 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity and lipid peroxidation inhibitory effects, as well as moderate reducing power and Fe2+ chelating activity. For the hepatoprotective activity, administration of ORWP and ORAP prevented the increase in serum alanine aminotransferase and aspartate aminotransferase activities in a carbon tetrachloride-induced acute liver damage model, suppressed hepatic malondialdehyde formation and stimulated the activities of hepatic superoxide dismutase and glutathione peroxidase. Thus, we speculate that ORWP and ORAP may protect the liver from CCl4-induced hepatic damage via antioxidant mechanisms.

Purification and Characterization of a White Laccase with Pronounced Dye Decolorizing Ability and HIV-1 Reverse Transcriptase Inhibitory Activity from Lepista nuda.

A strain LN07 with high laccase yield was identified as basidiomycete fungus Lepista nuda from which a white laccase without type I copper was purified and characterized. The laccase was a monomeric protein with a molecular mass of 56 kDa. Its N-terminal amino acid sequence was AIGPAADLHIVNKDISPDGF. Besides, eight inner peptide sequences were determined and lac4, lac5 and lac6 sequences were in the Cu(2+) combination and conservation zones of laccases. HIV-1 reverse transcriptase was inhibited by the laccase with a half-inhibitory concentration of 0.65 µM. Cu(2+) ions (1.5 mM) enhanced the laccase production and the optimal pH and temperature of the laccase were pH 3.0 and 50 °C, respectively. The Km and Vmax of the laccase using ABTS as substrate were respectively 0.19 mM and 195 µM. Several dyes including laboratory dyes and textile dyes used in this study, such as Methyl red, Coomassie brilliant blue, Reactive brilliant blue and so on, were decolorized in different degrees by the purified laccase. By LC-MS analysis, Methyl red was structurally degraded by the laccase. Moreover, the laccase affected the absorbance at the maximum wavelength of many pesticides. Thus, the white laccase had potential commercial value for textile finishing and wastewater treatment.

Developing CAR-immune cell therapy against SARS-CoV-2: Current status, challenges and prospects.

Chimeric antigen receptor (CAR)-immune cell therapy has revolutionized the anti-tumor field, achieving efficient and precise tumor clearance by directly guiding immune cell activity to target tumors. In addition, the use of CAR-immune cells to influence the composition and function of the immune system and ultimately achieve virus clearance and immune system homeostasis has attracted the interest of researchers. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggered a global pandemic of coronavirus disease 2019 (COVID-19). To date, the rapidly mutating SARS-CoV-2 continues to challenge existing therapies and has raised public concerns regarding reinfection. In patients with COVID-19, the interaction of SARS-CoV-2 with the immune system influences the course of the disease, and the coexistence of over-activated immune system components, such as macrophages, and severely compromised immune system components, such as natural killer cells, reveals a dysregulated immune system. Dysregulated immune-induced inflammation may impair viral clearance and T-cell responses, causing cytokine storms and ultimately leading to patient death. Here, we summarize the research progress on the use of CAR-immune cells against SARS-CoV-2 infection. Furthermore, we discuss the feasibility, challenges and prospect of CAR-immune cells as a new immune candidate therapy against SARS-CoV-2.

Evolutionary analysis of stakeholder behavior in green retrofitting of traditional residential buildings based on dissemination and game models.

To achieve carbon peaking and carbon neutrality goals in China, green retrofitting of traditional residential buildings is the one of the important ways. Therefore, the dynamics process of the change of the resident group intention to retrofit and its impact on the behavior of the tripartite game between the government, investment retrofitting enterprises and residents needs to be analyzed. Firstly, a dissemination model of green retrofitting intentions among resident groups is constructed, and it is coupled with the tripartite game model. Then, through numerical simulation, the dissemination laws of intention for green retrofitting among resident groups and its influence on the evolution process of the tripartite game are analyzed. The results show that: (1) The rate at which the triad of government, investment retrofitting enterprises and residents reaches steady state is influenced by the impact of changes in the level of social climate on the rate of conversion of potential and participating residents to immune residents. When the rate of enterprises investment and residents participation increases, the rate of government choice of incentive strategies decreases; (2) greater government regulation and subsidies will increase the intention of residents and retrofitting enterprises to participate. The ideal steady state without government incentives can be achieved when the group size of participating residents is increased by improving the level of government publicity and education and the technology level of the enterprises; (3) the intention of enterprises to invest is closely related to the cognitive benefits and the level of risk perception of residents. The conclusions of the study can be used as a reference for the government to make green retrofitting policies for traditional residential buildings.

Evolutionary analysis of resident groups' intention to participate in green retrofit PPP projects of traditional apartment complexes.

Green retrofit PPP projects of traditional apartment complexes play an important role in promoting the green and low-carbon transformation of the construction industry and achieving China's "double carbon" goals. The integrated retrofit of apartment complexes presupposes that the resident groups agree to the retrofit. Therefore, it is necessary to study the evolutionary mechanism of residents' intention to green retrofit and the transformation process of their behavior, and to explore how to enhance residents' intention to participate. First, the dissemination model of residents' intention to green retrofit is constructed. Then, the strategic interaction among government, social capitals and residents under the PPP model is introduced into the dissemination model to define the state transformation probability of resident groups. Finally, the evolution laws of residents' intention to green retrofit are analyzed. The results show that: (1) the behavior of government regulation and social capitals' effort to retrofit can motivate the number of the resident agreeing to green retrofit to meet the proportional limit, (2) the faster the government chooses the strategy of regulation and the social capitals choose the strategy of effort to retrofit, the faster the number of residents agreeing to green retrofit reaches a steady state, (3) when the level of government publicity and education is too low, the cost of government regulation or the subsidy given to residents is too high, the green retrofit of traditional apartment complexes cannot be achieved. The research conclusions can provide a reference for the government to formulate green retrofit policies.

A laccase with antiproliferative and HIV-I reverse transcriptase inhibitory activities from the mycorrhizal fungus Agaricus placomyces.

A novel 68 kDa laccase was purified from the mycorrhizal fungus Agaricus placomyces by utilizing a procedure that comprised three successive steps of ion exchange chromatography and gel filtration as the final step. The monomeric enzyme exhibited the N-terminal amino acid sequence of DVIGPQAQVTLANQD, which showed only a low extent of homology to sequences of other fungal laccases. The optimal temperature for A. placomyces laccase was 30°C, and optimal pH values for laccase activity towards the substrates 2,7'-azinobis[3-ethylbenzothiazolone-6-sulfonic acid] diammonium salt (ABTS) and hydroquinone were 5.2 and 6.8, respectively. The laccase displayed, at 30°C and pH 5.2, K(m) values of 0.392 mM towards hydroquinone and 0.775 mM towards ABTS. It potently suppressed proliferation of MCF 7 human breast cancer cells and Hep G2 hepatoma cells and inhibited human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) activity with an IC(50) of 1.8 µM, 1.7 µM, and 1.25 µM, respectively, signifying that it is an antipathogenic protein.

Harsh Parenting and Children's Aggressive Behavior: A Moderated Mediation Model.

Harsh parenting and its effect on children's aggressive behavior has received attention from researchers, however few studies have considered the role of the emotional process. This study aims to examine the relationship between harsh parenting, children's aggressive behavior, normative beliefs about aggression, and regulatory emotional self-efficacy, alongside their mechanism of interplay. A sample of 235 senior primary school students in Beijing were recruited as participants by using the Harsh Parenting Scale, the Normative Beliefs about Aggression Scale, the Buss-Warren Aggression Questionnaire, and the Regulatory Emotional Self-Efficacy Scale. Results indicated that: (1) Harsh parenting had a significant positive predictive effect on children's aggressive behavior after controlling gender; (2) normative beliefs about the aggression of children mediated the relationship between harsh parenting and children's aggressive behavior; and (3) regulatory emotional self-efficacy had moderating effects both the mediation model of normative beliefs about the aggression of children and in the direct predictive model of harsh parenting on children's aggressive behavior. The results are not only helpful to understand the relationship between harsh parenting and children's aggressive behavior from the perspective of an integrated model of emotion processes and cognition, but also provide a new practical way to prevent and intervene in children's aggressive behavior in the future.

The transcription factor FvHmg1 negatively regulates fruiting body development in Winter Mushroom Flammulina velutipes.

Fruiting body formation in Agaricomycetes represents the most complex and unclear process in the fungi. Mating type pathways (matA and matB) and transcription factors are important regulators in the process. Here, we report a new High-mobility-group (HMG) box domain protein FvHmg1 that acts as a negative transcription regulator in fruiting body development in Winter Mushroom Flammulina velutipes. However, the expression of Fvhmg1 in dikaryon and primordial stages was significantly lower than that of monokaryon. The Fvhmg1-RNAi mutants had a better ability of fruiting than wild type strain. Overall expression of Fvhmg1 was controlled under compatible matA and matB genes where compatible matA genes could increase its expression level, while compatible matB genes had the opposite effect. It means when two monokaryons with compatible matA and matB genes were crossed, the negatively transcription factor FvHmg1 was inhibited, and normal fully fruiting body could formation and develop. The relationship between FvHmg1 and mating type pathway would advance to understand of sexual reproduction and fruiting body development in edible mushrooms.

Integration of Pleurotus tuoliensis cultivation and biogas production for utilization of lignocellulosic biomass as well as its benefit evaluation.

The present study was to assess the economic benefit of integrated P. tuoliensis cultivation and biogas production based on the utilization of lignocellulosic biomass. Among the five evaluated cultivation substrates, that consisting of 55% cottonseed hull, 25% corncob, 10% wheat bran, 5% corn flour, 4% lime, and 1% gypsum was demonstrated to be optimal for the simultaneous production of P. tuoliensis mushrooms and biogas fuel. Preliminary estimation shows that, for the consumption of dry substrate per unit mass (calculated in per kg), a total of 561 g fresh mushroom product was harvested and 189.88 L biogas was generated. Accordingly, the production costs were abolished and an economic benefit of approximately $0.592 was obtained, with the high-value mushroom product being the main contributor to profit. Moreover, this integrated process also exhibited positive ecological and social benefits and as such, is worthy of promotion and further application.

Different roles of Rac1 in the acquisition and extinction of methamphetamine-associated contextual memory in the nucleus accumbens.

Rationale: Repeated methamphetamine (METH) exposure induces long-term cognitive deficits and pathological drug-associated memory that can be disrupted by manipulating memory reconsolidation and extinction. The nucleus accumbens (NAc) is the key region of the brain reward system and predominantly consists of two subtypes of medium spiny neurons (MSNs) based on the expression of D1 or D2 dopamine receptors (D1-MSNs or D2-MSNs). Spine structural plasticity in the NAc is critical for the acquisition, reconsolidation and extinction of drug-associated memory. However, the molecular mechanisms underlying METH-associated memory and spine remodelling in each type of MSNs in the NAc remain unknown. Here, we explored whether Rac1 in the NAc mediates METH-associated contextual memory and spine remodelling. Methods: Pharmacological and genetic manipulations of Rac1 were used to investigate its role during the acquisition, reconsolidation and extinction of METH-associated contextual memory. Recombinant adeno-associated viruses expressing mCherry under the control of the dopamine D1 receptor gene promoter (Drd1-mCherry) or dopamine D2 receptor gene promoter (Drd2-mCherry) were used to specifically label D1-MSNs or D2-MSNs. Results: Using viral-mediated gene transfer, we demonstrated that decreased Rac1 activity was required for the acquisition of METH-associated contextual memory and the METH-induced increase in thin spine density, whereas increased Rac1 signalling was important for the extinction of METH-associated contextual memory and the related elimination of thin spines. Moreover, the increase of dendritic spines was both found in D1-MSNs and D2-MSNs during the acquisition process, but extinction training selectively decreased the spine density in D1-MSNs. Interestingly, Rac1 was responsible for METH-induced spine plasticity in D1-MSNs but not in D2-MSNs. Additionally, we found that microinjection of a Rac1 inhibitor or activator into the NAc was not sufficient to disrupt reconsolidation, and the pharmacological activation of Rac1 in the NAc facilitated the extinction of METH-associated contextual memory. Regarding cognitive memory, decreased Rac1 activity improved the METH-induced impairment in object recognition memory. Conclusion: Our findings indicate that Rac1 plays opposing roles in the acquisition and extinction of METH-associated contextual memory and reveal the cell-specific role of Rac1 in METH-associated spine remodelling, suggesting that Rac1 is a potential therapeutic target for reducing relapse in METH addiction and remediating METH-induced recognition memory impairment.

Dopamine D1 and D2 Receptors Differentially Regulate Rac1 and Cdc42 Signaling in the Nucleus Accumbens to Modulate Behavioral and Structural Plasticity After Repeated Methamphetamine Treatment.

BACKGROUND: Methamphetamine (METH) is a highly addictive psychostimulant that strongly activates dopamine receptor signaling in the nucleus accumbens (NAc). However, how dopamine D1 and D2 receptors (D1Rs and D2Rs, respectively) as well as downstream signaling pathways, such as those involving Rac1 and Cdc42, modulate METH-induced behavioral and structural plasticity is largely unknown. METHODS: Using NAc conditional D1R and D2R deletion mice, Rac1 and Cdc42 mutant viruses, and a series of behavioral and morphological methods, we assessed the effects of D1Rs and D2Rs on Rac1 and Cdc42 in modulating METH-induced behavioral and structural plasticity in the NAc. RESULTS: D1Rs and D2Rs in the NAc consistently regulated METH-induced conditioned place preference, locomotor activation, and dendritic and spine remodeling of medium spiny neurons but differentially regulated METH withdrawal-induced spatial learning and memory impairment and anxiety. Interestingly, Rac1 and Cdc42 signaling were oppositely modulated by METH, and suppression of Rac1 signaling and activation of Cdc42 signaling were crucial to METH-induced conditioned place preference and structural plasticity but not to locomotor activation. D1Rs activated Rac1 and Cdc42 signaling, while D2Rs inhibited Rac1 signaling but activated Cdc42 signaling to mediate METH-induced conditioned place preference and structural plasticity but not locomotor activation. In addition, NAc D1R deletion aggravated METH withdrawal-induced spatial learning and memory impairment by suppressing Rac1 signaling but not Cdc42 signaling, while NAc D2R deletion aggravated METH withdrawal-induced anxiety without affecting Rac1 or Cdc42 signaling. CONCLUSIONS: D1Rs and D2Rs differentially regulate Rac1 and Cdc42 signaling to modulate METH-induced behavioral plasticity and the structural remodeling of medium spiny neurons in the NAc.

An extracellular yellow laccase from white rot fungus Trametes sp. F1635 and its mediator systems for dye decolorization.

A novel extracellular laccase was purified from fermentation broth of the white rot fungus Trametes sp. F1635 by a three-step protocol including two consecutive ion-exchange chromatography steps on DEAE-Sepharose and SP-Sepharose, and a final gel-filtration on Superdex 75. The purified laccase (TsL) was a monomeric protein with the molecular mass of 64.8 kDa. It demonstrated high oxidation activity of 4.00 × 104 U/mg towards ABTS. Its N-terminal amino acid sequence was AIGPVADLTIINNAV which was unique and sharing high similarity of other fungal laccases. TsL was a yellow laccase based on absorption spectrum analysis. It demonstrated an acidic pH optimum of 2.6 and temperature optimum of 50 °C towards ABTS. The Km and Vmax values towards ABTS were estimated to 18.58 µM and 1.35 µmol/min, respectively. TsL manifested effective decolorization activity towards eriochrome black T (EBT), remazol brilliant blue R (RBBR), malachite green (MG), and eriochrome black T (EBT) (over 60%). Violuric acid (VA) and acetosyringone (AS) were the optimal mediators for the laccase in dye decolorization. Results suggest that TsL demonstrates great potential for dye decolorization and water treatment.

Isolation of a protease-resistant and pH-stable α-galactosidase displaying hydrolytic efficacy toward raffinose family oligosaccharides from the button mushroom Agaricus bisporus.

A 45-kDa monomeric acidic α-galactosidase with a specific activity of 193.12 units/mg was isolated from the fruiting bodies of Agaricus bisporus. Blast search of internal peptide sequences suggested that it is a member of GH family 27 and it is most similar to hypothetical protein AGABI2DRAFT_70106. The enzyme displayed maximal activity at pH 4.0 and 60°C, respectively. The enzyme remained stable within the pH range 2.0-9.0 but its activity was markedly suppressed in the presence of Cu2+, Hg2+, Fe3+ and Ag+ ions. It displayed resistance to α-chymotrypsin and neutral protease. Moreover, it manifested degradative activity toward both oligosaccharides and polysaccharides. The enzyme manifested Km values of 0.30mM, 10.65mM and 19.21mM, toward pNPGal, stachyose and raffinose respectively. These results suggest that Agaricus bisporus α-galactosidase is a promising candidate for elimination of raffinose oligosaccharides (RFOs) in biotechnological applications.

An acidic feruloyl esterase from the mushroom Lactarius hatsudake: A potential animal feed supplement.

An acidic feruloyl esterase (lhFAE) from Lactarius hatsudake was purified to homogeneity, resulting in a high specific activity of 10.3U/mg toward methyl ferulate as substrate, which was 33.2-fold higher than that of the crude enzyme. lhFAE was a monomeric protein with a molecular mass of 55kDa. All three internal amino acid sequences exhibited 100% identity with the Laccaria bicolor carbohydrate esterase family 9 protein. The enzyme demonstrated high activity toward methyl ferulate (MFA) at an optimum pH of 4.0 and an optimum temperature at 30°C, and under these conditions, the Km and Vmax were 0.54mM and 13.84Umg-1, respectively. The purified FAE exhibited preference for methyl caffeate over methyl ferulate, and was least active on methyl p-coumarate. Interestingly, above 80% of the enzyme activity was preserved in the presence of metal ions at 5.0mM concentration, which indicated that lhFAE was highly metal-tolerant. lhFAE was able to release ferulic acid from de-starched wheat bran (DSWB) both in the absence and presence of xylanase, and 70.2% (of the total amount of) ferulic acid (FA) was released by the synergistic action of xylanase. The result showed that lhFAE has good acid and metal ion stability, and is suitable to be used as an animal feed supplement.

An extracellular yellow laccase with potent dye decolorizing ability from the fungus Leucoagaricus naucinus LAC-04.

A novel laccase was isolated from fermentation broth of the mycorrhizal fungus Leucoagaricus naucinus LAC-04 by using a protocol that comprising ion-exchange chromatography steps on DEAE-cellulose, SP-Sepharose, and Q-Sepharose, and finally gel filtration by fast protein liquid chromatography on Superdex 75. The laccase (LNL) was purified with a purification fold of 21.19 and a recovery rate of 19.8%. It is a monomeric protein with a molecular mass of 56kDa. LNL lacks absorption around 600nm, which indicates that the purified laccase is a yellow laccases. LNL demonstrates an optimal pH of 2.2 and an optimal temperature range of 30-60°C using ABTS as the substrate. It is inhibited in the presence of EDTA and metal ions including Cd2+, Co2+, Cu2+. The Km of the laccase towards ABTS is estimated to 50.12µM at pH 2.2 and 30°C. Moreover, the purified laccase manifests effective decolorizing activity towards azo, heterocyclic, and aromatic dyes including Bromothymol Blue, Eriochrome Black T, Evans Bue, Fuchsin Basic, and Remazol Brilliant Blue R.