No abstract

Isozyme data were used to identify populations of certain Lutzomyia taxa in the verrucarum species group, mostly in the series townsendi. Lutzomyia youngi Feliciangelis and Murillo and L. spinicrassa Morales, Osorno, Osorno, and Hoyos each have diagnostic allomorphs for phosphogluconate dehydrogenase (6PGDH) and fumarate hydratase (FUM). The 6PGDH and FUM data and those from 6-phospho-fructokinase and phosphoglucomutase distinguish Lutzomyia sp., a new species from Columbia to be described and named later. Data from these enzymes and glucose phosphate isomerase will separate L. townsendi (Ortiz) from the others and from L. longiflocosa Osorno, Morales, Osorno, and Hoyos, L. quasitownsendi Morales, Osorno, Osorno, and Hoyos, and L. sauroida Osorno, Morales, and Osorno (three species that are inseparable using enzyme data). Three other species, L. serrana (Damasceno and Arouck) (series serrana) and L. columbiana (Ristorcelli and Van Ty) and L. andina Osorno, Osorno, and Morales (both in series verrucarum), are morphologically distinct using conventional characters and have fixed diagnostic differences at several enzyme loci. Statistical analyses of the enzyme data using genetic identities (I), differences (D), and the amount of genetic variation among these taxa indicated that such statistics can be as useful in the study of sand fly phylogeny and population genetics as they have been for other organisms. I and D values indicated that L. longiflocosa, L. quasitownsendi, and L. sauroida are very similar (I = 0.991 and D = 0.010) and possibly are populations of the same conspecific species. The levels of divergence, based on combined enzyme data for up to 21 gene loci among the taxa, are discussed, and a dendrogram based on genetic distance is presented. The genetic data confirmed established phylogenetic relationships among the sand fly taxa based on structural similarities.

No abstract

In experimental murine infections with

SummaryProblems have been raised by natural genetic diversity of Trypanosoma cruzi, the causal agent of Chagas' disease, and other protozoa in terms of both basic and applied science. T. cruzi manifests a great diversity of medical and biological properties which could be the origin of clinical variability in the disease. We propose possible correlations between genetic distances, or phylogenetic divergence, and histopathological data. To ascertain this aspect, 15 cloned stocks pertaining to three major clones or genotypes (19, 20 and 39) were compared. Sets of 24 mice infected with each stock were studied for histopathological lesions. Brain, heart, lung, liver, spleen, urinary bladder, bone marrow, colon, kidney and skeletal muscle were extracted from each mouse. Qualitative and quantitative differences showed at histopathological examination. An important encephalic softening was found in brains of most mice infected by genotype 20, corresponding to areas of inflammation and liquified necrosis. Other inflammatory tissue lesions in the histological sections of the three genotypes were similar. Skeletal muscle tropism was higher than cardiac tropism in all the studied genotypes. All three genotypes shared parasite presence in skeletal muscle. Differences related to cardiac tropism were important: in genotype 19, 50% of studied stocks presented pseudocysts; 20% in genotype 20 and 83% in genotype 39. Parasite presence in other tissues was scanty: in brain only in genotype 20 and in spleen and liver only in genotype 39. We found important histopathogenicity differences among the three studied genotypes, but they do not support the hypothesis of zymodeme pathogenic specificity due to the great diversity among stocks within each genotype.keywords Trypanosoma cruzi, histopathological findings, genotype, genetic divergence correspondence Dr J. A.