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Temporal variability in biodeposit production by Chorornyhlus chorus (Molina) and Mytilus chilensis (Hupe) was studied from February 1989 to January 1990 in the Queule River Estuary, southern Chile. Biodeposits were collected monthly from PVC cylinders containing C. chorus or M. chilensis and analyzed for total dry weight, inorganic and organic weight and organic carbon and nitrogen content. Water characteristics (temperature, salinity, oxygen, chlorophyll a, seston) were also measured at each sampling period. The lughest biodeposition rates were calculated during spring and summer months; from October until January sedimentation and mussel biodeposition rates were similar. During this period the highest temperature and water salinities occurred, as well as one of the 2 chlorophyll a peaks observed during the study. The lowest biodeposition rates occurred during winter months, when temperature and water salinities were lowest and turbidity of the water was at its highest.

ABSTRACT. Changes in land use which directly or indirectly affect freshwater fauna constitute one of the principal anthropic factors which have caused world biological diversity to disappear rapidly during recent decades. This fauna includes aquatic benthic macroinvertebrates, organisms presenting temporal and spatial variation due to a variety of factors, one of which is the diverse food resources available in the rivers. To assess the effect of anthropic activities on this fauna, the distribution, abundance and characterisation of the functional feeding groups of aquatic macroinvertebrates were analysed, together with the physical and chemical variables in the environments of four coastal river basins of southern south-central Chile. A total of 104 taxa of macroinvertebrates were recorded, the principal component of the community being the Diptera (26 taxa). The abundance and richness of taxa were greater in summer and lower in winter. The most abundant species belong to the order Ephemeroptera and Plecoptera. Macroinvertebrates were affected by different land use: stations with less anthropic activity and greater altitude had higher macroinvertebrates abundance, while the lowest abundance was found at the lowest stations. The functional feeding groups which were most abundant spatially and temporally were the collector-gatherers and the shredders. The physical and chemical water quality variables proved to be of exceptional quality in all the stations. These results suggest that policies governing changes in land use in central and southern Chile should take into account the dramatic alterations that these changes impose on the macroinvertebrates community. Policies for biodiversity conservation should therefore focus on these small but important organisms in the north Patagonian region of South America, which is a hotspot of world diversity. Keywords: diversity, macroinvertebrates, functional feeding groups, land use, Chile.Composición del paisaje como determinante de la diversidad y de grupos funcionales alimentarios de macroinvertebrados acuáticos en ríos de la Araucanía, Chile RESUMEN. Los cambios en el uso de suelo que afectan directa o indirectamente la fauna dulceacuícola, son uno de los principales factores antropogénicos por los cuales la diversidad biológica mundial está desapareciendo a elevadas tasas durante las últimas décadas. Dentro de esta fauna se encuentran los macroinvertebrados bentónicos acuáticos, organismos que varían temporal y espacialmente debido a diversos factores, uno de los cuales son los diversos recursos alimentarios disponibles en los ríos. Para esto, se analizó la distribución, abundancia, y caracterización de los grupos funcionales alimentarios de macroinvertebrados, y las variables físicas y químicas de cuatro cuencas costeras del centro-sur de Chile. Un total de 104 taxa de macroinvertebrados fueron registrados, siendo los dípteros (26 taxa) el componente principal de la comunidad. La abundancia y riqueza de taxa fue más conspicua en verano y menor en invierno. Las especie...

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Lynch Syndrome (LS) is an inherited form of colorectal cancer caused by germline mutations in the Mismatch Repair (MMR) genes. It accounts for approximately 5% of all colorectal cancers. The prevalence of Lynch Syndrome among US Hispanics is unknown. The objective of this study was to describe the germline mutations of Lynch Syndrome in Caribbean Hispanics from Puerto Rico and Dominican Republic. A total of 89 subjects were recruited through the Puerto Rico Familial Colorectal Cancer Registry and were classified according to Amsterdam and Bethesda clinical guidelines. For those tumors with lack of expression of MMR protein, gene sequencing was ordered. A total of 35 individuals with deficient MMR system were identified: 22 had MMR mutations and 13 had tumors with absent MMR protein expression. Our results show that the mutation spectrum of Caribbean Hispanic LS patients was composed mostly of MSH2 (66.7 %) mutations, followed by MLH1 (25.0 %). One mutation was identified in MSH6 (8.3 %). A previously unidentified mutation in MLH1 gene c.2044_2045del was found in one Caribbean Hispanic family. MMR mutation-positive individuals were found to be more likely to have a prominent family history of CRC and tumors located at the proximal colon. Compared to MSH2 mutation carriers, MLH1 mutation-positive individuals were more likely to have a strong family history of CRC and LS associated cancers. Furthermore, insurance coverage for genetic testing was found to be limited in the study population with 65.1% of the individuals recruited were denied coverage. This report presents the first description of the mutation spectrum and clinicopathologic characteristics of LS Caribbean Hispanics patients.