Occurrence and characterization of injuries caused by Mycotretus apicalis Lacordaire, 1842 (Coleoptera: Erotylidae) on cultivation of Pleurotus sajor-caju

When carrying out experiments on the production of the edible mushroom Pleurotus sajor-caju in the Laboratory of Edible Mushrooms, Universidade Federal de Lavras, Lavras, Brazil, in the second half of 2007, the presence of beetles later identified as belonging to the species Mycotretus apicalis was verified. This is the first recorded instance of this insect in cultures of P. sajor-caju in Brazil. The larvae and adults of this insect feed on the fruiting bodies of commercial harvests, resulting in reduction in mushroom quality. To provide evaluation of the injuries caused by these insects, substrates colonized by P. sajor-caju were infested with 4, 8, 16, 32 and 64 insects per block of substrate being the qualitative and quantitative losses then noted. Despite the lack of an observed decrease in biological efficiency, the injuries caused by these insects affected the commercial quality of the mushrooms, which may result in economic losses. The results showed that infestations of 32 insects per 0.8 kg of substrate led to a depreciation in the prices of mushrooms meant to be sold.     

The 2-His-1-carboxylate facial triad: a versatile platform for dioxygen activation by mononuclear non-heme iron(II) enzymes

General knowledge of dioxygen-activating mononuclear non-heme iron(II) enzymes containing a 2-His-1-carboxylate facial triad has significantly expanded in the last few years, due in large part to the extensive library of crystal structures that is now available. The common structural motif utilized by this enzyme superfamily acts as a platform upon which a wide assortment of substrate transformations are catalyzed. The facial triad binds a divalent metal ion at the active site, which leaves the opposite face of the octahedron available to coordinate a variety of exogenous ligands. The binding of substrate activates the metal center for attack by dioxygen, which is subsequently converted to a high-valent iron intermediate, a formidable oxidizing species. Herein, we summarize crystallographic and mechanistic features of this metalloenzyme superfamily, which has enabled the proposal of a common but flexible pathway for dioxygen activation.     

AQUALINDERELLA FERMENTANS GEN. ET SP. N., A PHYCOMYCETE ADAPTED TO STAGNANT WATERS. II. ISOLATION,CULTURAL CHARACTERISTICS,AND GAS RELATIONS

This newly described member of the Leptomitales was incapable of growth in air on complex media routinely used to culture its nearest relatives. All attempts to isolate it in pure culture were unsuccessful until it was held in an atmosphere established by burning a candle in a sealed jar. Under these conditions it grew vigorously on various complex media and could be readily propagated in the laboratory in pure as well as in unifungal gross cultures. Like a number of other aquatic phycomycetes, A qualinderella fermentans proved to be a strong acid producer, its cultures requiring frequent neutralization during active growth. Work with pure cultures revealed a combination of gas relationships not described before among the fungi. A high level of atmospheric CO₂ is required, with good growth occurring between 5 and 20%. Growth also takes place under 99% CO₂. Supplemental CO₂ is partially replaceable by succinate. A. fermentans exhibits undiminished growth in an atmosphere of CO₂-supplemented hydrogen, essentially devoid of oxygen (leuco-methylene blue). These features are accompanied by an obligately fermentative energy metabolism. Ecologically, A. fermentans is adapted to an environment poor in oxygen and rich both in carbon dioxide and in fermentable organic matter. Such environments are likely to prevail in the warm, stagnant pools where this water mold has been found growing on submerged fruits. In many aspects of its cultural behavior and metabolism A. fermentans resembles another highly fermentative water mold, Blastocladia (Blastocladiales, Chytridiomycetes). The suggestion is made that in both instances parallel regressive evolution has occurred.