The action of lysostaphin, either alone or in combination with nisin, against established staphylococcal biofilm may represent an alternative to bovine mastitis control. However, the duration of the treatment should be considered for its application so that the best effectiveness can be achieved.

No abstract

Recently, there has been an increasing demand for new molecules with bioactivity as a result of the increasing number of multi drug resistant bacteria and also of the need to find treatment for various diseases. Thus, to fill this urging need there has been a great investment in developing new techniques to speed up and increase the possibility of finding new molecules with therapeutic potential. Typically, the first stage of drug discovery process relies on in vitro assays and conventional high-throughput LC-MS-MS approaches. This combined with unique extreme environments, as a source of new molecules, has proved to be a good approach to enlarge natural product drug discovery. Considering the present demand for new bioactive molecules, together with the fact that cave microorganisms are already considered an important, yet largely unexplored source, our study aimed at assessing the bioactive potential of cave bacterial extracts, namely its antimicrobial and antitumoral potential. From six soil samples collected in the Cerâmica cave, at the Sicó karst massif, centre of Portugal, a total of 409 isolates were obtained. After a primary screening with the cross-streak method, 91 isolates showed antagonistic activity against four pathogenic agents (Escherichia coli, Pseudomonas aeruginosa, Aeromonas salmonicida and Bacillus aquimaris). Afterwards the secondary screening was carried out with the three isolates that presented higher antimicrobial activity. For the secondary screening, cell-free supernatants (CFS) were tested against eight pathogenic agents (Escherichia coli, Pseudomonas aeruginosa, Aeromonas salmonicida, Bacillus cereus, Enterococcus faecalis, Klebesiella pneumoniae, Salmonella typhimurium and ‡ § ‡ ‡ ‡ © Veloso T et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Staphylococcus aureus). The chemical analysis of the CFS is discussed, as well as the results from the in vitro tests with human cell lines to evaluate its effects on cell morphology, viability and proliferation (Suppl. material 1).

Amphibians are frequently found exploring subterranean environments. Even though in Europe there are already some reports of amphibians present in subterranean habitats, in Portugal there is a major lack of knowledge of these ecosystems, namely in the karst region. Considering the relevance of amphibians and their current conservational status, it is important to assess their presence in every potential habitat. In order to provide further knowledge over this subject a preliminary survey was carried out in two Portuguese karst massifs, Estremenho and Sicó. A total of 24 caves were surveyed and as result three species (Tarentola mauritanica; Salamandra salamandra and Pleorodeles waltl) were found in Estremenho karst massif, and two species (Triturus marmoratus and Bufo bufo) were observed in Sicó karst massif. Furthermore, evidences were found that P. waltl uses caves for reproduction, which had only been reported once in Spain. This allowed perceiving that herpetofauna species occupy caves of Portuguese karst massifs and are also using them as reproduction sites.

Amphibians in Portugal are commonly found in karst ecosystems. Nonetheless, these ecosystems are threatened by activities such as agricultural and industrial activities and mining, which contaminate both surface water and groundwater. Due to the high permeability of the karst systems, the existence of water on the surface is scarce, with sinkhole ponds and springs representing essential water sources for amphibians, especially for their reproduction. Furthermore, water from springs may reflect the effects of surface contamination on groundwater. Considering the relevance of these water sources, specially to amphibians, which are considered highly sensitive to a widerange of contaminants, our study aimed at assessing the suitability of water from springs and sinkholes from two Portuguese karst massifs, for the development of the early lifestages of Hyla arborea. To achieve this, eggs from H. arborea were exposed to water from seven springs and four sinkholes, from the Estremenho and Sicó karst massifs, anda control (FETAX). The exposure was carried out with five replicates per condition, each with 20 tadpoles, and ended once the 25th Gosner stage was reached. The parameters evaluated were growth, antioxidant enzyme activity (Glutathione STransferases, Glutathione Peroxidase Se-dependent, total-Glutathione Peroxidase and Glutathione Reductase) and lipid peroxidation (LPO). Also, water samples were screened for the presence of six commonly used pesticides (Terbuthylazine, Tebuconazole, Deltamethrin, Dimethomorph, Chlorpyrifos and Glyphosate). The results revealed the presence of glyphosate in three of the sampled water bodies. Concurrently, in one of the sites presenting detectable glyphosate concentrations, tadpoles presented smaller body lengths, and mortality was also observed. In the remaining sites, despite the absence of the screened pesticides, there were some alterations of the biochemical parameters assessed, namely LPO. These results raised some concerns regarding the impact of human activities in surface and groundwater in the Sicó and Estremenho karst massifs.