María Muñoz

Evaluation of different bacteriophage groups as faecal indicators in contaminated natural waters in southern England

Abstract River and seawater affected by faecal discharges were analysed to evaluate the reliability of coliphages and F-specific RNA bacteriophages as indicators of the microbiological quality of waters. F-specific RNA bacteriophages showed no direct relationship with the levels of faecal pollution, and this group was never detected in samples with a low level of enteroviruses (1–10 pfu/10 l.). In contrast, coliphages were constantly detected in the same samples. The concentration of coliphages detected in the samples with 1–10 and > 10 pfu/101. of enteroviruses were similar and higher than the Economical European Community guide and imperative levels of faecal coliforms (100 and 2000 FC/100 ml, respectively). Therefore, coliphages would be considered as an optimal indicator of the microbiological quality of the natural waters.

Relationships between salmonella spp and indicator microorganisms in polluted natural waters

Abstract The relationships between Salmonella spp and indicator microorganisms (total coliforms, faecal coliforms, faecal streptococci, Clostridium perfringens and coliphages) were investigated in three different aquatic environments affected by wastewater discharges. The results indicated that the statistical correlations obtained depended, basically, on the source of faecal discharges. The microorganisms most closely correlated with Salmonella spp were faecal coliforms and C. perfringens , the latter also yielding the highest linear regression slope values. The detection percentages of Salmonella spp were high even at a low degree of pollution, which allowed detection of the pathogens in the absence of classical indicator microorganisms in the sample.

Microbial colonization of different support materials used to enhance the methanogenic process.

Macrobial colonization of the different support materials used to enhance methane production in anaerobic digestors is rapid and occurs in the first 24 h of sludge incubation. Scanning electron microscopy studies reveal a predominant presence of filamentous methanogenic forms, closely resemblingMethanosaeta (Methanothrix), which are located on the outer layer and in the bacterial framework of the biofilm. These findings are consistent with the results obtained from microbial counts using both the most probable number and epifluorescence microscopic techniques, which show an increase in the numbers of aceticlastic methanogens compared to other microbial groups involved, such as sulphate-reducing bacteria, the numbers of which are similar to those obtained under the initial conditions. Moreover, a sharp increase in the bacterial counts is observed by using the epifluorescence microscopic technique applied to homogenized samples, probably due to the count of bacteria released from the support materials.

Viability ofSalmonella species in natural waters

The viability of different species ofSalmonella in seawater was studied under controlled laboratory conditions. The negative influence of water self-purifying factors exerted on the survival of the microorganisms varied depending on the factor considered and also on the specie selected. Biotic and luminous factors were mainly responsible for the inactivation and disappearance ofSalmonella in the water solutions. The addition of 1% of sewage to filtered seawater and freshwater provoked a decrease in the number ofSalmonella populations tested in comparison with the solutions without sewage. On the other hand, an increase of sublethally injuredSalmonella cells with respect to exposure time was not observed. From the results obtained from T90 inactivation experiments, it may be deduced that the main factor implicated in the disappearance ofSalmonella from the water mass is physical dilution.

Evaluating Protocols for Porcine Faecal Microbiome Recollection, Storage and DNA Extraction: from the Farm to the Lab

There is a growing interest in understanding the role of the gut microbiome on productive and meat quality-related traits in livestock species in order to develop new useful tools for improving pig production systems and industry. Faecal samples are analysed as a proxy of gut microbiota and here the selection of suitable protocols for faecal sampling and DNA isolation is a critical first step in order to obtain reliable results, even more to compare results obtained from different studies. The aim of the current study was to establish in a cost-effective way, using automated ribosomal intergenic spacer analysis technique, a protocol for porcine faecal sampling and storage at farm and slaughterhouse and to determine the most efficient microbiota DNA isolation kit among those most widely used. Operational Taxonomic Unit profiles were compared from Iberian pig faecal samples collected from rectum or ground, stored with liquid N2, room temperature or RNAlater, and processed with QIAamp DNA Stool (Qiagen), PowerFecal DNA Isolation (Mobio) or SpeedTools Tissue DNA extraction (Biotools) commercial kits. The results, focused on prokaryote sampling, based on DNA yield and quality, OTU number and Sørensen similarity Indexes, indicate that the recommended protocol for porcine faecal microbiome sampling at farm should include: the collection from porcine rectum to avoid contamination; the storage in liquid N2 or even at room temperature, but not in RNAlater; and the isolation of microbiota DNA using PowerFecal DNA Isolation kit. These conditions provide more reliable DNA samples for further microbiome analysis.

Fertilization and connectivity in the Garrucha Canyon (SE-Spain) implications for Marine Spatial Planning

Marine Spatial Planning is usually based on benthic georeferenced information or GPS tracked human activities, whereas the pelagic ecosystem is often ignored because of scarce and limited surface information. However, the 3-D pelagic ecosystem plays a key role connecting all the other ecosystems by physical (currents) and biological (migration) processes. According to remote sensing the Garrucha Canyon is oligotrophic, but 3-D sampling reveals subsurface upwelling, and converts it into the richest area around the Cape of Gata. Vertical connectivity by means of zooplankton migration, measured at two sampling stations, is 40 and 220 times faster than microphytoplankton settling and vertical water velocities respectively. Thus coupled physical-biological connectivity models are necessary to estimate the ecosystem connection and the fate of carbon, but also other substances (e.g. radioactivity), that might accumulate throughout the food-web. This is especially important in the Garrucha Canyon and the Coastal Areas Management Programme Levante de Almería where natural heritage and extractive fishery are important for the local economy.