Service-Learning, Movies, and Infectious Diseases: Implementation of an Active Educational Program in Microbiology as a Tool for Engagement in Social Justice

Service-Learning is an educational methodology that allows student learning while addressing community needs. A program in microbiology and infectious diseases was implemented in Universidad Complutense de Madrid, Spain. University lecturers, clinical microbiologists, doctorate students, and undergraduates from several Bachelor Degrees and courses worked in an interdisciplinary team along with social institutions that attend disadvantaged persons. Using commercial movies that deal with infectious diseases, the students learn clinical microbiology, prepare divulgation materials, visit social centers to accompany, and help others to know about illnesses and prevention. The program was developed through two academic years and involved 58 voluntary students, 13 teachers and tutors, and 4 social entities as community partners. Postsurvey evaluation of the program revealed a highly satisfactory achievement of goals: acquiring scientific and personal competencies by university students, including critical analysis and science diffusion, solving problems or collaborative team working, and contributing, together with the tutors, to the social responsibility of the university.

Anisakid parasites of two forkbeards (Phycis blennoides and Phycis phycis) from the Mediterranean coasts of Andalucía (Southern Spain)

An epidemiological survey of anisakids was carried out on 209 specimens of greater forkbeard (Phycis blennoides) and 58 of forkbeard (Phycis phycis) captured off the Mediterranean coasts of Andalucía (southern Spain). Four species of nematodes were identified: Anisakis simplex s.l., Anisakis physeteris, Hysterothylacium aduncum and Hysterothylacium fabri. The total prevalence was 62.06% in the forkbeard and 58.85% in the greater forkbeard. The highest values of prevalence (56.90%), mean intensity (5.21) and mean abundance (2.96) were all obtained for H. fabri in the forkbeard. The most frequent parasite in the greater forkbeard was H. aduncum with 51.20% prevalence and values of 3.00 and 1.53 for mean intensity and mean abundance, respectively. The infestation parameters were also analyzed according to the host length, observing a maximum of parasitized fish (91.67%) in samples of P. blennoides longer than 40 cm, while in P. phycis, the highest prevalence (82.35%), conditioned by H. fabri parasitization, was found in fish with lengths between 30 and 35 cm.

Pentadiene production from potassium sorbate by osmotolerant yeasts

Some yeast strains belonging to the species Zygosaccharomyces rouxii and Debaryomyces hansenii are capable of spoiling sorbate containing high-sugar foods by producing pentadiene, a volatile compound reported to have 'petroleum-like' odour. Quantification of the diminution of sorbate and the subsequent increase of pentadiene was performed by growing the yeasts in experimental media containing 600 g/l sucrose and different sorbate concentrations. Final sorbate concentrations were notably lower than their corresponding initial ones, and it was found that the higher the initial concentration of sorbate in the media, the higher the amount of pentadiene produced. In all cases, Z. rouxii was able to produce more pentadiene than D. hansenii when expressing pentadiene concentration as a function of cell biomass. These results suggest that pentadiene is a metabolite of sorbate.

A chromogenic medium for the detection of yeasts with beta-galactosidase and beta-glucosidase activities from intermediate moisture foods

A selective and differential solid medium for the specific detection of some common yeasts frequently causing spoilage in intermediate moisture foods is described. The principle of the method is based on the detection of two enzymes, beta-glucosidase and beta-galactosidase, using the chromogenic substrates salmon-Gluc and X-Gal. Over 140 yeasts and bacteria were tested, and Debaryomyces hansenii and Kluyveromyces marxianus strains produced salmon and dark blue colonies, respectively, thus permitting their clear discrimination from other yeasts common in intermediate moisture foods. The medium was very satisfactory when intermediate moisture foods were tested.

A differential medium for the isolation of Kluyveromyces marxianus and Kluyveromyces lactis from dairy products

A selective and differential solid medium, called Kluyveromyces Differential Medium (KDM), is described for the isolation of Kluyveromyces marxianus and K. lactis from dairy products. Its discriminative potential is based on the detection of the enzyme beta-galactosidase, in the absence of lactose. Of the more than 95 strains tested, including yeasts, bacteria, and filamentous fungus, only the strains of K. marxianus and K. lactis produced blue colonies on the medium due to the presence of X-Gal/ IPTG. The bacterial strains were not able to grow in KDM. On this basis, the medium was very satisfactory when testing naturally or experimentally contaminated dairy food products. When quality assessment tests were performed, optimal values of productivity (growth and color) and selectivity were obtained for K. marxianus and K. lactis.

Influence of salt concentration on the cellular fatty acid composition of the moderately halophilic bacterium Halomonas salina

The cellular fatty acid composition of Halomonas salina, a moderately halophilic bacterium grown at different salt concentrations, is reported. Fatty acids C16:0 and C18:1 were major components and significant amounts of C16:1, C18:0 and cyc-C19:0 were also detected. The results showed clear chemotaxonomic relationships with recognized members of the genus Halomonas. The salt concentration greatly influenced the fatty acid composition, suggesting activation of cyclopropane synthetase at high levels of salt, since increases in cyclopropane fatty acids with decreases in monounsaturated fatty acids were observed as the salt concentration in the medium rose.

Orthogonal representations of random fields and an application to geophysics data

We present a brief summary of some results related to deriving orthogonal representations of second-order random fields and its application in solving linear prediction problems. In the homogeneous and/or isotropic case, the spectral theory provides an orthogonal expansion in terms of spherical harmonics, called spectral decomposition (Yadrenko 1983). A prediction formula based on this orthogonal representation is shown. Finally, an application of this formula in solving a real-data problem related to prospective geophysics techniques is presented.

Assessment of phenotypic and genetic diversity in the yeast genus Metschnikowia

The taxonomy of the yeast genus Metschnikowia has undergone profound changes over the past century. Major developments, from the capacity to obtain pure cultures of parasitic species to progress associated with the extensive use of molecular biology tools in yeast systematics, are briefly reviewed. Results from past work and new data are combined to evaluate evolutionary relationships and clarify the classification of both terrestrial and aquatic species. Recent physiological studies, including the utilization of non-conventional carbon and nitrogen sources, and characteristics like lipolytic activity and maximum temperatures for growth, are presented. The assessment of the genetic diversity within the genus by restriction analysis of the mitochondrial DNA and by the production of specific DNA probes has been explored. The results indicate the potential application of the latter in rapid identification procedures.

Numerical taxonomy of moderately halophilic gram-positive cocci isolated from the Salar de Atacama (Chile)

A taxonomic study has been carried out on 22 strains of moderately halophilic motile cocci isolated from the Salar de Atacama (Chile). The 112 phenotypic tests were analyzed by numerical taxonomy using SSM coefficient and the unweighted pair group method of association (UPGMA). At the 67% similarity level, two phenons were obtained: phenon A included 11 strains and phenon B, 11 strains too, whereas the six reference strains did not cluster within these two phenons. These results suggest that moderately halophilic cocci with different phenotypic characteristics from previously described species can be isolated from the hypersaline habitat Salar de Atacama.

Effect of external salinity changes on cellular composition of some ions and amino acids in Deleya halophila

Changes in total cellular composition of some ions and amino acids of the moderate halophile Deleya halophila were studied in response to external salinity changes. Among the 14 amino acids investigated, the cellular glycine and aspartic acid content increased with increasing salinity. D. halophila also accumulated Na+ at the highest external salt concentrations.

Isolation and characterization of moderately halophilic nonmotile rods from different saline habitats

A total of 736 strains were isolated from samples taken from three different saline habitats: solar saltern, saline soils and the sea, near Alicante (Spain). For a further study 60 moderately halophilic nonmotile rods were selected and studied for 57 phenotypic characteristics. The highest proportion of moderately halophilic nonmotile rods were isolated from saline soils and in media with 10 or 20% salts, being very scarce in sea water samples. All were Gram-negative rods and were included in two groups: 33 oxidase positive strains could be assigned to the genus Flavobacterium and 24 oxidase negative strains to the genus Acinetobacter.