New biomaterial based on cotton with incorporated biomolecules

The aim of this study was to investigate a method of embedding l-cysteine (l-cys), an antimicrobial agent, between layers of chitosan (CH) and sodium alginate (ALG) onto cotton samples obtained via a layer-by-layer electrostatic deposition technique via several embedding methods. The results show that the best way to incorporate l-cys into the layers was the one that used the property of gelling ALG. To monitor the l-cys embedding into the CH/ALG multilayer film, different methods were used: energy-dispersive X-ray spectrometry analysis to assess the presence of sulfur on the sample, Ellman's reagent method to analyze l-cys release from the sample, and attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR) to compare the ATR–FTIR spectra of the pure l-cys and l-cys embedded in the CH/ALG multilayer film to study the interaction between the l-cys and the CH/ALG multilayer films. Functionalized CH/ALG cotton samples were also investigated for their antibacterial properties toward Staphylococcus aureus andKlebsiella pneumonia with the Japanese Industrial Standard method JIS L 1902:2002, and the results show an enhancement of the antibacterial effect due to the presence of l-cys.The authors thank Fundação para a Ciência e Tecnologia for the funding granted concerning the project PTDC/EBB-BIO/113671/ 2009 (FCOMP-01-0124-FEDER-014752). Also, they thank Fundo Europeu de Desenvolvimento Regional through COMPETE—Programa Operacional Factores de Competitividade for cofunding

Spillover but no spillback of two invasive parasitic copepods from invasive Pacific oysters (Crassostrea gigas) to native bivalve hosts

Invasive species can cause indirect effects on native biota by modifying parasite-host interactions and disease occurrence in native species. This study investigated the role of the invasive Pacific oyster (Crassostrea gigas) in potential spillover (co-introduced parasites infect native hosts) and spillback (native or established parasites infect invasive hosts and re-infect native hosts) scenarios of recently introduced (Mytilicola orientalis) and previously established (Mytilicola intestinalis) marine parasitic copepods in two regions in northern Europe, the Dutch Delta and the Wadden Sea. By examining 3416 individuals of 11 potential host species from sympatric host populations, we found that the recently introduced parasite M. orientalis does not only infect its principal host, the invasive Pacific oyster (prevalence at infected sites 2–43 %, mean intensity 4.1 ± 0.6 SE), but also native blue mussels (Mytilus edulis; 3–63 %, 2.1 ± 0.2), common cockles (Cerastoderma edule; 2–13 %, 1.2 ± 0.3) and Baltic tellins (Macoma balthica; 6–7 %, 1.0 ± 0), confirming a spillover effect. Spillback effects were not observed as the previously established M. intestinalis was exclusively found in blue mussels (prevalence at infected locations 3–72 %, mean intensity 2.4 ± 0.3 SE). The high frequency of M. orientalis spillover, in particular to native mussels, suggests that Pacific oysters may cause strong parasite-mediated indirect impacts on native bivalve populations