The presence of macrophytes changes the beta diversity of Ephemeroptera,Plecoptera, and Trichoptera (EPT) assemblages in Cerrado streams in Northeastern Brazil

Limnology - In-stream conditions can affect the distribution of the Ephemeroptera, Plecoptera, and Trichoptera orders (EPT) because they require specific food resources and good quality water....     

Mineralisation of carbon and plant uptake of phosphorus from microbially-derived organic matter in response to 19 years simulated nitrogen deposition

Here we test the hypotheses that 19 years of simulated pollutant N deposition increases both losses of carbon (C) and the ability of plants to access P from organic material in upland heathland. The grass, Dactylis glomerata, and the dwarf shrub, Calluna vulgaris, were grown in soil containing microbial-derived organic matter labelled with ¹⁴C and ³³P. We found that both soil and root-surface phosphatase activity increased significantly in response to N deposition. We also found a significant positive relationship between root-surface phosphatase activity and ³³P uptake for Calluna, but a negative relationship for Dactylis. Efflux of ¹⁴C from the microbial-derived organic matter was strongly dependent on an interaction among plant presence, plant species and N deposition. Our results show that mineralisation of C and P, and subsequent plant uptake of P from organic sources is decoupled. In our experimental conditions, stimulation of P turnover coupled with subsequent plant uptake through up-regulation of root phosphatases is little affected by N addition. However, our data indicate that root-surface phosphatases are likely to be more important for uptake of P derived from organic sources for Calluna than for Dactylis.     

Fluorescently tagged iminoalditol glycosidase inhibitors as novel biological probes and diagnostics

1,5-Dideoxy-1,5-imino-D-glucitol, the corresponding D-manno and L-ido epimers as well as the powerful beta-glucosidase inhibitor isofagomine were N-alkylated with di-, tri-, as well as tetraethylene glycol derived straight chain spacer arms by a set of simple standard procedures. The terminal functional groups of the spacer arms, primary amines, were employed to introduce fluorescent dansyl moieties. Resulting derivatives showed glycosidase inhibitory activities comparable to those of the parent compounds'.