RESUMO

En Chile se ha detectado la presencia de algunos géneros de cianobacterias que pueden producir potentes hepatotoxinas y neurotoxinas, las que pueden ser letales para humanos y animales. En el presente trabajo se determinó la presencia de dos géneros de cianobacterias no tóxicos: Chroococcus y Spirulina; y cuatro géneros de cianobacterias productores de toxina, Anabaena, Anabaenopsis, Microcystis y Oscillatoria en tres diferentes cuerpos de agua de la V Región: Lago Peñuelas (Valparaíso), Tranque Recreo (Villa Alemana) y Embalse Los Aromos (Limache). Además se detectó la presencia de hepatotoxinas por MALDI-TOF MS encontrándose microcistina-RR, -LA, -YR y nodularina en Embalse Los Aromos, microcistina-LA en Tranque Recreo y microcistina-RR y LA en Lago Peñuelas. Adicionalmente en algunas de las muestras se detectó la presencia de péptidos no tóxicos, que presentan actividad biológica tales como aeruginosinas, cianopeptolinas y microgininas. Como estos cuerpos de agua dulce son utilizados para abastecimiento público y para la recreación, es importante diseñar planes de tratamiento y monitoreo para detectar y evitar los riesgos a la salud humana y animal provocado por estos microorganismos.

In Chile the presence of some genera of cyanobacteria that may cause potent hepatoxins and neurotoxis has been detected, which may become lethal for man and animal. In this paper the occurrence of two non toxic genera of cyanobacteria: Chroococcus and Spirulina was established along with four genera of toxin-producing cyanobacteria, Anabaena, Anabaenopsis, Microcystis and Oscillatoria in three different masses of water from the V Region: Lago Peñuelas (Valparaíso), Tranque Recreo (Villa Alemana) and Embalse Los Aromos (Limache). Likewise the presence of hepatoxins by MALDI-TOF MS was detected which resulted in the occurrence of microcystina-RR, _LA , -YR and nodularina in Embalse Los Aromos, microcystina –LA in Tranque Recreo and microcystina -RR and LA in Lago Peñuelas. Moreover, the presence of non toxic peptides developing biological activities such as aeruginosinas, cianopeptolins and microgininines was detected. Considering that these freshwater bodies are intended for public supply and recreational purposes, it is of utmost importance to design treatment and supervising plans in order to detect and prevent risks for human and animal health caused by these microorganisms.

Assuntos

RESUMO

A large number of halophilic bacteria were isolated in 1984-1992 from the Atacama Saltern (North of Chile). For this study 82 strains of extreme halophilic archaea were selected. The characterization was performed by using the phenotypic characters including morphological, physiological, biochemical, nutritional and antimicrobial susceptibility test. The results, together with those from reference strains, were subjected to numerical analysis, using the Simple Matching (S(SM)) coefficient and clustered by the unweighted pair group method of association (UPGMA). Fifteen phena were obtained at an 70% similarity level. The results obtained reveal a high diversity among the halophilic archaea isolated. Representative strains from the phena were chosen to determine their DNA base composition and the percentage of DNA-DNA similarity compared to reference strains. The 16S rRNA studies showed that some of these strains constitutes a new taxa of extreme halophilic archaea.

Assuntos

RESUMO

A cyanobacterial bloom occurring in 1998 in lake Tres Pascualas (Concepción/Chile) was found to be dominated by Microcystis sp. The bloom contained both non-toxic (cyanopeptolin-type) and hepatotoxic (microcystin-type) peptides. Cyanopeptolin structure of the non-toxic peptides (called cyanopeptolin VW-1 and VW-2, respectively) was revealed by matrix assisted laser desorption ionization mass spectrometry (MALDI-TOF-MS) of whole cells, showing dominant molecular ions at m/z = 975 and m/z 995, respectively. On post source decay (PSD), both cyanopeptolins showed fragments deriving from Ahp-Phe-MTyr (3-amino-6-hydroxy-2-piperidone), the characteristic partial structure of cyanopeptolins. The amounts of each of the two cyanopeptolins could only roughly be estimated to be >0.1% of bloom material dry weight. In addition the blooms contained microcystins (20 microg/g bloom dry weight as determined by RP-HPLC, 13 microg/g according to ELISA determination). MALDI-TOF-MS revealed several structural variants of microcystin: MCYST-RR (microcystin with Arg and Arg, indicated by m/z 1,038 and confirmed by PSD revealing a m/z = 135 fragment deriving from the Adda side chain, MCYST-FR (microcystin with Phe and Arg, indicated by m/z = 1,015). The presence of [Asp(3)]-MCYST-LR (microcystin with Leu and Arg, Asp non-methylated, indicated by m/z 981), and [Asp(3)]-MCYST-YR (microcystin with Tyr and Arg, Asp non-methylated, indicated by m/z 1,031) were likely. The relative amounts of the peptides varied between February, April, and May. Whole cell extracts from the bloom material revealed specific enzyme inhibitory activities. The serin-proteases trypsin, plasmin, elastase were inhibited, assumable due to the cyanopeptolins found. Elastase and the cysteine-protease papain were not inhibited, inhibitions of protein kinase and glutathione S-transferase (GST) were low. Strong inhibition was observed with protein-phosphatase-1, likely due to the microcystins present in the samples.

Assuntos

RESUMO

Cyanobacterial blooms dominated by Microcystis sp. occurred in lake Rocuant ("marisma", near Concepción/Chile) in February 1995 and 1996. In the bloom samples collected in both years the hepatotoxin microcystin was detected by RP-HPLC in both samples and in the sample of 1995 also by a toxicity assay using primary rat hepatocytes. In the bloom of 1995, the microcystin content of the dry bloom biomass was determined to be 130 micrograms/g on the basis of the RP-HPLC peak area and 800 micrograms/g on the basis of the rat hepatotoxicity assay, respectively. In the bloom of 1996, RP-HPLC analysis revealed a microcystin content of 8.13 micrograms/g bloom material dry weight. In this year no hepatotoxicity was measured using a concentration range up to 0.8 mg (d. w.) of bloom material per ml in the rat hepatotoxicity assay. This is the first report on the detection of microcystins in Chilean water bodies.

Assuntos