Biogeochemical markers across a pollution gradient in a Patagonian estuary: A multidimensional approach of fatty acids and stable isotopes.

A combined approach merging stable isotopes and fatty acids was applied to study anthropogenic pollution in the Río Negro estuary. Fatty acid markers of vegetal detritus indicated considerable allochthonous inputs at freshwater sites. Correlative evidence of diatom fatty acids, δ13C, chlorophyll and particulate organic matter suggested the importance of diatoms for the autochthonous organic matter production at the river mouth. Low δ15N values (~0‰) and high fatty acid 18:1(n-7) concentrations in the suspended particulate matter, in combination with the peaks of coliforms and ammonium, indicated a strong impact of untreated sewage discharge. The 15N depletion was related to oxygen-limited ammonification processes and incorporation of 15N depleted ammonium to microorganisms. This work demonstrates that the combined use of lipid and isotopic markers can greatly increase our understanding of biogeochemical factors and pollutants influencing estuaries, and our findings highlight the urgent need for water management actions to reduce eutrophication.

Vulnerability of pejerrey Odontesthes bonariensis populations to climate change in pampean lakes of Argentina.

The vulnerability of the pejerrey Odontesthes bonariensis population in Lake Chasicó was assessed under different climate change conditions. During the sampling period, the water temperature was adequate for fish reproduction and to sustain an adequate sex ratio. Climate-driven higher temperatures, however, may severely distort population structure and cause drastic reduction or local extinction of stocks. Lake Chasicó can be classified as eutrophic with clear waters and cyanobacteria that regularly cause fish mortality were identified as Nodularia spumigena and Oscillatoria sp. Global warming may strengthen the effects of eutrophication (e.g. toxic blooms or anoxia). Since many Cyanophyta species tolerate higher temperatures better than other algae, toxic blooms could increase. Furthermore, cyanobacteria have low nutritional value and could decouple the low-diversity food web. Lake Chasicó has currently the salinity optimum (c. 20) for the development of the early life-history stages of O. bonariensis. Climate change, however, is likely to amplify the intensity of droughts or inundations. Floods can endanger O. bonariensis development due to its sub-optimal growth at low salinity and droughts could increase lake salinity and also temperature and nutrient concentration. In order to reduce some of the effects of climate change on the O. bonariensis population in Lake Chasicó, integrated basin management based on an eco-hydrological approach is proposed.

A highly sensitive and specific multiplex PCR assay for simultaneous detection of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus.

AIMS: To develop an effective multiplex PCR for simultaneous and rapid detection of Vibrio cholerae, Vibrio vulnificus and Vibrio parahaemolyticus, the three most important Vibrio species that can cause devastating health hazards among human. METHODS AND RESULTS: Species-specific PCR primers were designed based on toxR gene for V. cholerae and V. parahaemolyticus, and vvhA gene for V. vulnificus. The multiplex PCR was validated with 488 Vibrio strains including 322 V. cholerae, 12 V. vulnificus, and 82 V. parahaemolyticus, 20 other Vibrio species and 17 other bacterial species associated with human diseases. It could detect the three target bacteria without any ambiguity even among closely related species. It showed good efficiency in detection of co-existing target species in the same sample. The detection limit of all the target species was ten cells per PCR tube. CONCLUSIONS: Specificity and sensitivity of the multiplex PCR is 100% each and sufficient for simultaneous detection of these potentially pathogenic Vibrio species in clinical and environmental samples. SIGNIFICANCE AND IMPACT OF THE STUDY: This simple, rapid and cost-effective method can be applicable in a prediction system to prevent disease outbreak by these Vibrio species and can be considered as an effective tool for both epidemiologist and ecologist.

[The function of polymorphonucleocytes: chemotaxis, the nitroblue tetrazolium test and myeloperoxidases in healthy children and adults]. / Estudio de la función de los polimorfonucleares: quimiotaxis, "test" del nitroazul de tetrazolio y mieloperoxidasas en niños y adultos sanos.

Polymorphonuclear leucocytes function--chemotaxis, NBT and myeloperoxidase--was studied in 31 children and 62 healthy adults. Chemotaxis was superior in adults (p less than 0.001), while the other test had a similar behaviour. Results show that there is a dissociation on the maturity of different functions of the neutrophil, and it is necessary to dispose of age-matched controls to evaluate chemotaxis in children.

[Study of serum C3 and C4 fractions in patients with glucose-6-phosphate dehydrogenase deficiency (author's transl)]. / Estudio del C3 y C4 en el déficit en glucosa-6-fosfato deshidrogenasa.

Activity of serum C3 and C4 fractions have been measured in 35 individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency and various clinical manifestations. Determination of serum complement was carried out in six cases during an abrupt hemolytic phase; the remaining 29 patients were asymptomatic at the time of laboratory test, but the past history revealed acute hemolytic syndroe in 11 cases. There were no statistical significant differences between C3 and C4 fraction levels of patients with G6PD deficiency and those corresponding to a group of 30 normal controls. Immunoallergic theories causing hemolytic episodes in patients with G6PD deficiency are discussed.