Pseudoperoxidase activity of mushroom tyrosinase

Under anaerobic conditions, ethyl hydroperoxide functions as a two-electron acceptor in the tyrosinase-catalyzed oxidation of 4-tert-butylcatechol to 4-tert-butyl-o-benzoquinone, apparently by the following mechanism:

$\text{T?[Cu(II)]}{}_2\text{+ TBC = T?[Cu(I)]}{}_2\text{+ TB?}\text{o?}\text{BQ + 2H}{}^{\mathrm{+}}$

$\text{T?[Cu(I)]}{}_2\text{+ EtOOH + 2H}{}^{\mathrm{+}}\text{= T?[Cu(II)]}{}_2\text{+ EtOH +H}{}^2\text{O}$

This is a direct demonstration of the pseudoperoxidase activity of tyrosinase. Ethyl hydroperoxide failed to oxidize either oxy- or deoxyhemocyanin.     

Neuropeptides in insect mushroom bodies

Owing to their experimental amenability, insect nervous systems continue to be in the foreground of investigations into information processing in – ostensibly – simple neuronal networks. Among the cerebral neuropil regions that hold a particular fascination for neurobiologists are the paired mushroom bodies, which, despite their function in other behavioral contexts, are most renowned for their role in learning and memory. The quest to understand the processes that underlie these capacities has been furthered by research focusing on unraveling neuroanatomical connections of the mushroom bodies and identifying key players that characterize the molecular machinery of mushroom body neurons. However, on a cellular level, communication between intrinsic and extrinsic mushroom body neurons still remains elusive. The present account aims to provide an overview on the repertoire of neuropeptides expressed in and utilized by mushroom body neurons. Existing data for a number of insect representatives is compiled and some open gaps in the record are filled by presenting additional original data.     

Ferroxidase activity of mushroom tyrosinase

Mushroom tyrosinase catalyses the oxidation of Fe(II) to Fe(III). Both the newly-discovered ferroxidase and the well-characterized diphenol oxidase activities of tyrosinase exhibit inhibition by cyanide and both activities co-purify during two preparation steps. The characteristics of tyrosinase-catalysed Fe(II) oxidation are compared with those of other ferroxidases.     

食用菌培植业思考与展望

食用菌生产应该与种植业、养殖业并驾齐驱,称之为食用菌培植业,是农业生产领域内的三大基础产业。解决野生食用菌的产量、质量问题,是野生食用菌产业化开发的瓶颈;必须另辟蹊径,发展食用菌原生态野生化生产,实现野生食用菌的规模化、产业化发展。对双孢蘑菇野生化生产和菌菜轮作进行了探讨,为我国双孢蘑菇的生产发展另辟蹊径;建议我国的双孢蘑菇生产朝两化一作的方向发展。     

食用菌表型组技术研究进展

食用菌己成为我国农业的第五大种植业,在"精准扶贫"战役中发挥了重要作用.然而,经过40年的快速发展,食用菌行业依然面临着众多问题亟待解决,尤其是在工厂化栽培生产中我们还严重依赖国外选育的菌种.随着基因测序和表型组等新技术的蓬勃发展,"数据驱动"的生物学研究取得了一系列突破性进展.这些新技术也为解决食用菌行业面临的问题带...     

Quaternary structure of mushroom tyrosinase

The quaternary structure of $\text{Agaricus}$$\text{bispora}$ tyrosinase has been investigated by sodium dodecylsulfate-acrylamide gel electrophoresis. The enzyme was found to contain two types of polypeptide chains, referred to as Heavy, molecular weight 43,000 ± 1,000, and Light, molecular weight 13,400 ± 600. In aqueous solution the predominant form of tyrosinase m.w. 120,000, has the quaternary structure L₂H₂.     

Hydrodynamic properties of mushroom tyrosinase

The hydrodynamic properties of mushroom tyrosinase were determined at pH 6.5 using a Sephadex G-200 column. From the comparison of its gel-filtration behaviour with those of standard proteins, the following parameters were calculated: MW (122 500 ± 1%), Stokes' radius (42.75 × 10^?8 cm²/sec), diffusion coefficient (5.048 × 10^?7 cm²/sec) and frictional ratio (1.26). These values suggest a globular conformation of this enzyme.     

食用菌病毒的研究进展

病毒是引起食用菌发生病害的重要病原之一,由于其具有潜隐性、不易辨认的特点,因而难以被人们所察觉,一旦发病就难以控制。在食用菌研究领域中,食用菌病毒使食用菌产量严重下降,引起的病害越来越受人们的重视,逐步成为该领域的研究热点。因此,本文主要针对食用菌病毒的结构与分类、危害、传播方式、检测方法以及食用菌病毒的脱毒技术等方面进行了综述,并对其存在的问题和前景进行了展望。这为食用菌病毒的检测、脱毒和无毒菌种的生产提供了理论依据,并为食用菌病毒的深入研究提供参考。     

Harnessing synthetic biology for mushroom farming

Recent advances in synthetic biology have transformed mushroom farming from a focus on traditional cultivation to comprehensive applications based on cutting-edge biotechnologies. Synthetic biology has promising applications in this field, including precision breeding, mining biosynthetic gene clusters, developing mushroom chassis cells, and constructing cell factories for high value-added products.     

Inhibition of mushroom tyrosinase by tropolone

Tropolone inhibits both mono- and o-dihydroxyphenolase activity of mushroom tyrosinase. Most of the inhibition exerted by tropolone was reversed by dialysis or by excess CU²⁺. The data indicate that tropolone and o-dihydroxyphenols compete for binding to the copper at the active site of the enzyme. Comparison between the effectiveness of various copper chelators showed that tropolone is one of the most potent inhibitors of mushroom tyrosinase; 50% inhibition was observed with 0.4 × 10^?6 M tropolone.     

Modern aspects of mushroom culture technology

The production and culture of new species of mushrooms is increasing. The breeding of new strains has significantly improved, allowing the use of strains with high yield and resistance to diseases, increasing productivity and diminishing the use of chemicals for pest control. The improvement and development of modern technologies, such as computerized control, automated mushroom harvesting, preparation of compost, production of mushrooms in a non-composted substrate, and new methods of substrate sterilization and spawn preparation, will increase the productivity of mushroom culture. All these aspects are crucial for the production of mushrooms with better flavor, appearance, texture, nutritional qualities, and medicinal properties at low cost. Mushroom culture is a biotechnological process that recycles ligninocellulosic wastes, since mushrooms are food for human consumption and the spent substrate can be used in different ways.