Laccases from Actinobacteria—What We Have and What to Expect

Laccases are blue multicopper enzymes, capable of oxidizing diverse aromatic and non-aromatic compounds of industrial interest, concomitantly with reduction of molecular oxygen to water. Tolerance to extreme conditions, such as high temperature, salinity or extreme pH, is required for practical industrial applications. Here we focus on bacterial laccases from the phylum Actinobacteria, notably the order Actinomycetales. Currently, less than 10 enzymes have been properly characterized, all belonging to genus Streptomyces, but it is noteworthy that all of them have exhibited industrially important properties. Furthermore, studies with enzymes from this phylum revealed a novel molecular structure of laccases, providing the basis for a distinct family, the two-domain laccases. The relevant traits of actinomycetes laccases emphasize the need for more studies involving the isolation of this bacterial group from lignin-rich environmental samples, detection of their laccase activity and thereafter, characterization of the proteins and related genes. The nonhomogeneous responses of actinomycetes laccases to traditional inhibitors, substrates or metal ions have challenged the currently accepted “laccase concept”. Finally, considering that distinguishing laccase activity in vitro from other ligninolytic enzymes becomes a difficult task due to overlaps in catalytical properties of the enzymes, we proposed a simple flow chart to help experimental assays.

Land Use Capability and the Sustainable Scale: An Overview of Agriculture in São Paulo State, Brazil

Establishing a sustainable scale in natural resources management enables effective economic and ecological policies and guarantees the long-term sustainability of economic production. In agriculture, land evaluations determine the land use sustainable scales, that is, those that avoid land degradation and allow the provision of food, wood, energy, and ecosystem services over time. The paper assessed São Paulo State’s agricultural sustainability by analyzing the current land use adequacy to the land use capability map that follows FAO 1976 “guide for land evaluation” and was applied to São Paulo by the State Agricultural Secretariat. Results indicate inefficiencies in land use at the state level, where more than one-third of agricultural lands do not satisfy technical land capability indications. According to technical land use capability, more than 4.5 million hectares are being underused (economic inefficiency) and another 2.2 million hectares are being overused (environmental inefficiency). Pasturelands represent the most unsustainable land use, where 3.7 million hectares are allocated in high quality lands with high agricultural production potential, and another 0.7 million hectares are allocated in lands with very low quality for agriculture, most of than area degraded. To achieve sustainability, lands with high agricultural production potential should be used to improve agriculture and food production and, on the other hand, lands with very low agricultural production potential should be used for wood production, agroforestry, ecotourism and natural ecosystems conservation. Our results provide a framework for improving land use policies in São Paulo State and highlight an opportunity to achieve land use sustainability.

Queens remate despite traumatic mating in stingless bees

Males can control female reproduction using genital plugs to impede access by rivals.In social bees,ants,and wasps,plugging may involve traumatic mating,with females being harmed.In stingless bees,chances are that plugs may promote ovarian activan,and are thought to ensure single mating—a general tendency among the social Hymenoptera.However,understanding on relationships between mating plugs,traumatic mating,and mating systems in stingless bees remains limited.To address this,we(1)compared mated queens of 7 Neotropical species to understand the patterns of copulatory marks in females and(2)compared pre-and post-mating genitalia of males and females in Melipona fasciculata to depict plug functional morphology.Data revealed an unprecedented consequence of mating in stingless bees:the characteristic marks left by mating plugs on female abdomens and the inferences that can be made from them.To our surprise,in 1 species M.fasciculata we found that queens retain the plug long after mating,and may carry it for the rest of their lives.All the other 6 species retained the plug for only a short period.Remated queens were only found in M.seminigra,whose multiple copulatory marks match previous findings of polyandry in this species.Our study shows that queens can remate,and suggests that male genital morphology may determine in part the time persistence of plugs.We conclude that traumatic mating plugs do not fully prevent remating in stingless bees and that mating systems are not uniform in this group.Nonetheless,exceptional cases of facultative polyandry in social insects—for example,when mating plugs fail—may confirm a general tendency for single mating in close link with efficient mating plugs.