FUNCTIONAL ALPHA-TROPOMYOSIN PRODUCED IN ESCHERICHIA-COLI - A DIPEPTIDE EXTENSION CAN SUBSTITUTE THE AMINO-TERMINAL ACETYL GROUP

Unlike the muscle protein, alpha-tropomyosin expressed in Escherichia coli does not bind actin, does not exhibit head-to-tail polymerization, and does not inhibit actomyosin ATPase activity in the absence of troponin. The only chemical difference between recombinant and muscle tropomyosins is that the first methionine is not acetylated in the recombinant protein (Hitchcock-DeGregori, S. E., and Heald, R. W. (1987) J. Biol. Chem. 262, 9730-9735). We expressed three fusion tropomyosins in E. coli with 2, 3, and 17 amino acids fused to its amino terminus. Ah three fusions restored actin binding, head-to-tail polymerization, and the capacity to inhibit the actomyosin ATPase to these unacetylated tropomyosins. Unlike larger fusions, the small fusions of 2 and 3 amino acids do not interfere with regulatory function. Therefore the presence of a fused dipeptide at the amino terminus of unacetylated tropomyosin is sufficient to replace the function of the N-acetyl group present in muscle tropomyosin. A structural interpretation for the function of the acetyl group, based on our results and the coiled coil structure of tropomyosin, is presented.

Placentation in cloned cattle: Structure and microvascular architecture

To elucidate the morphological differences between placentas from normal and cloned cattle pregnancies reaching term, the umbilical cord, placentomes and interplacentomal region of the fetal membranes were examined macroscopically as well as by light and scanning electron microscopy. In pregnancies established by somatic nucleus transfer (NT), the umbilical cord and fetal membranes were edematous. Placentomal fusion was common, resulting in increased size and a decreased number of placentomes. Extensive areas of the chorioallantoic membrane were devoid of placentomes. An increased number of functional or accessory microcotyledons (< 1 cm) were present at the maternally oriented surface of fetal membranes. Extensive areas of extravasated maternal blood were present within the placentomes and in the interplacentomal region. The crypts on the caruncular surface were dilated and accommodated complexes of more than one primary villus, as opposed to a single villus in non-cloned placentae. Scanning electron microscopy of blood vessel casts revealed that there was also more than one stem artery per villous tree and that the ramification of the vessels failed to form dense complexes of capillary loops and sinusoidal dilations as in normal pregnancies. At the materno-fetal interface, however, the trophoblast and uterine epithelium had normal histology. In conclusion, the NT placentas had a range of pathomorphological changes; this was likely associated with the poor clinical outcome of NT pregnancies. (c) 2007 Elsevier B.V. All rights reserved.

KARYOTYPE STUDIES IN 22 SPECIES OF PARROTS (PSITTACIFORMES, AVES)

The karyotypes of 12 species of Psittaciformes new to cytology are described: Lorius hypoinochrous, L. lory and Phigys solitarius of the Loriidae, and Amazona autumnallis, Aratinga jandaya, Eclectus roratus, Pionus maximiliani, P. menstruus, P. senilis, P. seniloides, Poicephalus senegalus and Polytelis alexandrae of the Psittacidae. The karyotypes of Amazona ochrocephala, Ara ararauna, Ara macao, Psittacula krameri, Psittacus erithacus and Pyrrhura molinae of the Psittacidae have been previously described. For reasons of comparison the karyotypes of Aratinga aurea, Forpus xanthopterygius, Brotogeris sanctithomae and B. versicolorus of the Psittacidae are also described. These karyotypes are compared to those in the literature and the karyological relationships in the Psittaciformes are briefly discussed. Microchromosome fusions and translocations and pericentric inversions probably are responsible for the heterogeneity of karyotypes in the Psittaciformes.

Chromosomal evolution in Gekkonidae. I. Chromosome painting between Gekko and Hemidactylus species reveals phylogenetic relationships within the group

Geckos are a large group of lizards characterized by a rich variety of species, different modes of sex determination and diverse karyotypes. In spite of many unresolved questions on lizards' phylogeny and taxonomy, the karyotypes of most geckos have been studied by conventional cytogenetic methods only. We used flow-sorted chromosome-specific painting probes of Japanese gecko (Gekko japonicus), Mediterranean house gecko (Hemidactylus turcicus) and flat-tailed house gecko (Hemidactylus platyurus) to reveal homologous regions and to study karyotype evolution in seven gecko species (Gekko gecko, G. japonicus, G. ulikovskii, G. vittatus, Hemidactylus frenatus, H. platyurus and H. turcicus). Generally, the karyotypes of geckos were found to be conserved, but we revealed some characteristic rearrangements including both fissions and fusions in Hemidactylus. The karyotype of H. platyurus contained a heteromorphic pair in all female individuals, where one of the homologues had a terminal DAPI-negative and C-positive heterochromatic block that might indicate a putative sex chromosome. Among two male individuals studied, only one carried such a polymorphism, and the second one had none, suggesting a possible ZZ/ZW sex determination in some populations of this species. We found that all Gekko species have retained the putative ancestral karyotype, whilst the fission of the largest ancestral chromosome occurred in the ancestor of modern Hemidactylus species. Three common fissions occurred in the ancestor of Mediterranean house and flat-tailed house geckos, suggesting their sister group relationships. PCR-assisted mapping on flow-sorted chromosome libraries with conserved DMRT1 gene primers in G. japonicus indicates the localization of DMRT1 gene on chromosome 6.

Caracterização da fusão caruncular em gestações naturais e de conceptos bovinos clonados

Barreto R.S.N., Miglino M.A., Meirelles F.V., Visintin J.A., Silva S.M., Burioli K.C., Fonseca R., Bertan C., Assis Neto A.C. & Pereira F.T.V. 2009. [Characterization of the caruncular fusion in gestations of natural and cloned bovine conceptuses.] Caracterizacao da fusao caruncular ern gestacoes naturais e de conceptos bovinos clonados. Pesquisa Veterinaria Brasileira 29(10):779-787. Laboratorio de Morfofisiologia da Placenta e Embriao, Faculdade de Zootecnia, Universidade Estadual Paulista, SP294 Km 651, Dracena, SP 17900-000, Brazil. E-mail: fverechia@dracena.unesp.brThe objective of the study was to compare the characteristics of the caruncular fusion in gestations of non-cloned and cloned conceptuses. The non-cloned conceptuses were divided according to the gestation period: Group 1 (2 to 3 months; n=9),II (4 to 6; n=9); III (7 to 8; n=10) and IV (9 n=7). The cloned conceptuses formed the Group V: 9 months; n=4. The caruncles were observed macroscopically (number and dimensions: length, width and height), microscopically and submitted to statistical analysis (5% of significance). We observed three types of macroscopic caruncular fusions: oval (morphologically normal); two united adjacent caruncles and the lobulated type, characterized by regions with several united caruncles presenting a false fusion or deformation of the caruncular parenchyma. The length of the caruncles was 1.55 +/- 0.57; 2.45 +/- 0.55; 4.66 +/- 2.0 and 5.72 +/- 1.90cm for the groups 1, 11, 111, IV respectively. As for the height, the caruncles presented a lineal growth during the gestation: 0.40 +/- 0.15; 0.57 +/- 0.21; 1.0 +/- 0.48 and 1.80 +/- 0.91cm, for the respective groups 1, 11, 111 and IV. The width of the caruncles was similar between the groups I and 11 (0.97 +/- 0.30 e 1.42 +/- 0.71 cm) and the groups III and IV (2.68 +/- 1.22 and 3.52 +/- 1.16cm). When the group V was compared to the IV, the caruncles of the group V presented a larger length (5.72 +/- 1.90 vs. 7.88 +/-.13cm) and width (3.52 +/- 1.16 vs. 4.93 +/- 1.46cm), however they were similar in height (1.80 +/- 0.91 and 2.25 +/- 0.67cm). We verified that in gestations of cloned conceptuses the caruncles presented a larger development than in gestations of non-cloned conceptuses. The fusioned caruncles presented measurements statistically similar to the isolated ones in all the parameters and groups. Under light microscopy, we observed the formation of a stromal axis from the basis of the caruncle to the apex of the fusional fissure, with the histological constitution similar to the endometrial stroma. Three microscopic shapes were also unpublished defined: true fusion with a single axis evident below the fusional fissure; pseudofusion with a double axis in H shape and false fusion with absence of the axis. The first two formats were associated to the oval and lobulated caruncles and the last one to the false fusion with deformation of the caruncle parenchyma. The fusional axis increased in size along the gestation among the groups I, II, III and IV. The group V presented a larger length and width of the axis when compared to the group IV. Thus, in gestations of cloned conceptuses a destruction of the lateral epithelium of the caruncles is associated to an incompetence in the maternal-fetal interdigitation, that compromises the cotyledonary fusion. We suggest that, in gestations derived of cloned conceptuses, the increase of the size of the caruncular fusions is possibly associated to a compensatory mechanism for the metabolic exchanges between mother and fetus, in reason of the smallest number of isolated caruncles.

Nucleolar changes in malpighian tubules cells of Rhodnius prolixus during starvation

This study focused on nuclear and nucleolar area changes in Malpighian tubule cells of Rhodnius prolixus, an hematophagous insect, vector of Chagas' disease. Male and female adult insects were dissected after a 28-day starvation period, as well as insects which had been fed again after a 30-day starvation period. Malpighian tubules were fixed and silver stained. In both, males and females, nucleolar fusions and regions of nucleolar corpuscles were observed to be differentially impregnated by silver during feeding stress. In the males and females that were fed again, nucleolar corpuscles were partially fusioned, indicating a slight recovery upon the 30-day starvation period. The changes observed in the nucleolar phenotype and in both nuclear and nucleolar areas indicated that, as a result of stress, a more intense, compensatory activity occurred to supply the metabolic rate. The mechanism of this phenomenon may be associated to the decondensation and activation of chromatin that carries rDNA in order to increase rRNA transcription, and,consequently, protein synthesis.

Chromosomal diversification of diploid number, heterochromatin and rDNAs in two species of Phanaeus beetles (Scarabaeidae, Scarabaeinae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Anticorpos monoclonais em imunohematologia

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

Análise citogenética comparativa em espécies de morcegos dos gêneros Molossus (Molossidae), Artibeus, Platyrrhinus, Sturnira, Glossophaga, Phyllostomus e Carollia (Phyllostamide) - Chiroptera (Mammalia)

Pós-graduação em Genética - IBILCE

Produção e caracterização de anticorpos monoclonais contra antígeno de metacestóides de Taenia saginata

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dinâmica populacional e comportamento predatório individual da aranha social Parawixia bistriata (Rengger) (Araneae: Araneidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação do cimento de alfa-fosfato tricálcico em artrodeses tarsocrurais experimentais em cães

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mapeamento cromossômico comparativo em peixes ciclícos utilizando sequências repetitivas de DNA

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evolução cromossômica no veado-mateiro – Mazama americana (Mammalia; Cervidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

GQ e Men's Health: os estilos de vida do ator masculino contemporâneo

Pós-graduação em Linguística e Língua Portuguesa - FCLAR