Resumo em Inglês:

The Hardy-Weinberg law has been used widely for about one hundred years with little question as to the foundations laid down by its originators. The basic assumption of random mating, that is choice of mates by a process akin to that of a lottery, was shown to produce genotypic proportions following the "binomial-square" rule, the so-called Hardy-Weinberg proportions (HWP). It has been assumed by many that random mating was the only way of pairing genes capable of producing HWP. However it has been shown that HWP can be obtained and maintained by non-random mating. The steps along the way to this revelation and some implications are reviewed.

Resumo em Inglês:

Hemoglobinopathies are the most common monogenic disorders worldwide; however, they have never been systematically studied from a genetic perspective in Uruguay. In this study, we determined the frequencies of hemoglobin variants in Afro-Uruguayans. A sample of 52 healthy unrelated Afro-Uruguayans from the northern (N = 28) and southern (N = 24) regions of the country was analyzed. Eight individuals (15.4%) were heterozygous for -alpha3,7thalassemia; seven of them (29.2%) were originally from the southern region, whereas one of them (3.6%) was from the northern region; the differences between both regions were statistically significant (p = 0.016 +/-0.003). The only structural mutation detected was betaS, which is typical of African populations. Four individuals (10%) were heterozygous for betaS, three of them (13.6%) from the South, and one (5.6%) from the North. The betaS haplotypes were analyzed in eight individuals: two were homozygous betaS/betaS, two were heterozygous betaS/betathal, and four were heterozygous betaS/betaª. This haplotype distribution (60% Bantu, 20% Benin, and 20% Bantu A2) is in agreement with historical records reporting a predominantly Bantu origin for the enslaved Africans brought to Uruguay. Even though this is a preliminary study, due to the small sample size, our results are suggestive of a relatively high incidence of hemoglobinopathies in the Afro-Uruguayan population.

Resumo em Inglês:

We describe two different novel mutations in the PAX3 gene, detected in two families with cases of Waardenburg syndrome type I (WSI). The missense mutation detected in one family involved a single substitution in exon 2 (c.142 G > T) and was present both in the affected individual and in his clinically normal father. The mutation found in the second family consisted of a deletion of 13 bases, c.764-776del(TTACCCTGACATT), in exon 5.

Resumo em Inglês:

We investigated 50 Mulatto and 120 White Brazilians for the Y-chromosome short tandem repeat (Y-STR) markers (DYS19, DYS390, DYS391, DYS392 and DYS393) and found 79 different haplotypes in the White and 35 in the Mulatto sample. Admixture estimates based on allele frequencies showed that the admixture of the white sample was 89% European, 6% African and 5% Amerindian while the Mulatto sample was 93% European and 7% African. Results were consistent with historical records of the directional mating between European males and Amerindian or African females.

Resumo em Inglês:

The structurally complex MYCL1 microsatellite marker is often used to determine microsatellite instability in colorectal cancers but the allelic variation of this marker has remained largely uncharacterized in both populations and in cancers. Our study describes the allelic distributions of MYCL1 in Finnish (n = 117) and Somali population samples (n = 61) of non-related individuals and compares this distribution with the instability pattern obtained from 61 gastrointestinal tumors.

Resumo em Inglês:

Gene polymorphisms involved in the metabolism of drugs and chemical carcinogens seem to be responsible for differences in the susceptibility of individuals to cancer, but genetic population studies are needed to characterize these polymorphisms in different ethnic populations. We investigated polymorphisms of the cytochrome P450 (CYP) gene CYP1A1 and the glutathione S-transferase (GSTs) genes GSTM1, GSTT1 and GSTP1 in a sample of Afro-Brazilians from the southern Brazilian city of Porto Alegre to verify if there were ethnic differences compared to the polymorphisms of the same genes in a previously described sample of Brazilians of European descent from the same city. The allele frequencies detected in the Afro-Brazilian population investigated in this study were CYP1A1*2A (30%) and GSTP1*Val (42%) while the frequency of the GSTM1 null genotype was 34% and that of the GSTT1 null genotype was 28%. Significant differences in genotype distribution and allelic frequencies were detected between Brazilians of African and of European descent from Porto Alegre in terms of the polymorphisms CYP1A1*2A (p = 0.003), GSTP1-Ile105Val (p = 0.002) and the GSTM1 null genotype (p = 0.01) but there was no detectable significant difference in respect to GSTT1 null genotype frequencies.

Resumo em Inglês:

Campomelic dysplasia (CD) is an autosomal dominant skeletal malformation syndrome with features including bowed lower limbs with pretibial skin dimpling, hypoplastic scapulae and pelvic bones, and 11 pairs of ribs. Mutations in the SOX9 gene have been identified to cause CD. The gene encodes a transcription factor containing a dimerization, a high mobility group, and a C-terminal transactivation (TA) domain. Up to now, 35 SOX9 mutations have been published. In the present study, we describe a Thai girl with clinically and radiologically typical CD. Direct sequencing analysis of the PCR products for the entire coding region of SOX9 revealed that she was heterozygous for a novel 448G > T in exon 2 of SOX9. The DNA change was expected to result in E150X and loss of the entire TA domain. This result further supports that SOX9 is the only gene, discovered to date, responsible for CD across different populations and that the TA domain is important to the function of the normal SOX9.

Resumo em Inglês:

We used differential staining techniques (BSG, GTG, AgNO3, DAPI and CMA3 banding) and fluorescent in situ hybridization (FISH) with 5S and 18S probes to investigated the karyotypic and cytogenetic chracteristics of Prochilodus lineatus specimens from a population in Vila Velha state park (Parque Estadual de Vila Velha, Ponta Grossa, Paraná state, southern Brazil). The specimens studied showed the same karyotype as that found in other P. lineatus populations, i.e. 2n = 54 biarmed chromosomes (40m + 14 sm) and c-positive heterochromatin preferentially located pericentromerically in all chromosomes. The presence of partial or totally heterochromatic supernumerary chromosomes with numeric intra-individual variation was confirmed in the analyzed population. The nucleolar organizing regions (NORs) were interstitially situated on the long arm of chromosome pair 4 directly beneath the centromere. The differential banding techniques and FISH revealed NOR size polymorphism due to structural events such as breaks and duplication of the larger rDNA site cluster. We also observed syntenic localization of the 5S ribosomal genes in the distal segment of the 45S cluster.

Resumo em Inglês:

Characterization of different strains of common carp (Cyprinus carpio L.) using molecular markers is essential for the management of this fish in respect to the evaluation of the potential genetic effects induced by hatchery operations and the genetic improvement of carp varieties. Five microsatellite loci (MFW1, MFW2, MFW11, MFW15 and MFW20) were analyzed for the molecular characterization of four common carp strains, i.e. scaled carp, mirror carp, red carp and koi carp. We observed differences in heterozygosities and the average numbers of alleles but not in polymorphic loci (P95) among the strains. Koi carp displayed the highest level of variability in terms of heterozygosity. The Nm values and the F ST values indicated a low level of gene flow and high level of differentiation among the strains. The highest genetic distance was observed between the scaled carp and the koi carp whilst the lowest genetic distance was found between the red- and koi carp. The unweighted pair group method with averages (UPGMA) dendrogram resulted in two clusters, one containing only the scaled carp and the other the remaining three varieties. Microsatellite markers have been found to be effective tools for characterization of different strains of common carp.

Resumo em Inglês:

The association between G316A growth hormone polymorphism and quantitative traits was investigated in an F2 population of pigs. Association analyses were performed using a statistical model that included genotype, sex, batch and sex by genotype interaction as fixed effects and sire as random effect. The polymorphism was associated with the number of right teats (p = 0.03), heart weight (p = 0.04), lung weight (p = 0.05), carcass length determined by the Brazilian carcass classification method (p = 0.04), picnic shoulder weight (p = 0.07), jowl weight (p = 0.01), pH 24 h after slaughtering (p = 0.03) and drip loss (p = 0.01). Interaction between genotype and sex was observed for six performance traits. The additive effect was significant (p < 0.10) for heart weight, jowl weight and pH 24 h after slaughtering. The effect of dominance was significant (p < 0.05) for number of right teats, heart weight, carcass length, picnic shoulder weight and pH 24 h after slaughtering. This study shows that the growth hormone gene is a potential candidate for investigating the phenotypic variation of quantitative traits in pigs, and suggests its possible application in breeding programs.

Resumo em Inglês:

The effect of the bovine major histocompatibility complex (BoLA) locus on animal health may be due to a direct action of its alleles on immune functions, whereas its indirect effect on production traits might be explained by the better general health conditions of more productive animals. In the present study, the BoLA-DRB3 gene was investigated in 1058 cows belonging to seven Brazilian Gyr Dairy herds (Bos indicus, Zebu cattle). A total of 37 alleles were identified, 15 of them described for the first time in a Zebu breed. A highly significant association (p < 0.02) was observed between allele *54 and a decrease (-26.1 kg) in milk protein yield and there was a significant association (p < 0.05) between this allele and lower (-26.07 kg) milk fat yield. There was also a significant association (p < 0.05) between allele *6 and decreased (-12.47 kg) milk protein and allele *7 and increased (12.72 kg) milk protein. There were also indications of association (p < 0.10) between somatic cell score (SCS) and alleles *3 (SCS increased by 0.54 units) and *31 (SCS increased by 0.46 units). The highly significant association of allele *54 with lower protein yield suggests the possible use of this allele in marker-assisted selection programs.

Resumo em Inglês:

There are few studies on weight covering the full life cycle of Zebu cattle, and there is no entire growth description or mean growth pattern for animals belonging to this breed. In order to provide such data, 1,158 Nelore females born between 1985 and 1995 were weighed 14,563 times from birth to full growth maturity, in ten herds spread over seven Brazilian states. The Von Bertalanffy, Brody, logistic and Gompertz non-linear models were used to obtain the asymptotic weights (A) and the maturation rates (K). The (co)variance and breeding value components for A and K were obtained by using the multiple trait derivative free restricted maximum likelihood method under the animal model. Genetic trends were calculated in function of the mean expected progeny differences (EPD) for the trait (A or K) divided by the number of animals according to their year of birth. The genetic trends of the expected progeny difference with reference to the date of birth of the cows were, on average, -6.5g y-1 for A and 2.0g y-1 for K, close to zero as confirmed by the low (0.0023 to 0.003) coefficient of regression values. The curve parameters are recommended as a selection criterion to reach precocity and avoid adult weight increase in the female herd.

Resumo em Inglês:

The fish Dormitator maculatus has a chromosomes number of 2n = 46, females having a karyotype of 14 M, 28 SM, 2 ST and 2A and males 13 M, 28 SM, 3 ST and 2A. The presence of a heteromorphic pair in the males and a corresponding homomorphic pair in the females suggest the occurrence of an XX/XY sex chromosome system in D. maculatus. The putative X chromosome has a pericentromeric C-band positive segment and the putative Y chromosome a C-band positive short arm.

Resumo em Inglês:

We used conventional chromosomal staining to describe the karyotype of the critically endangered Lear's macaw, Anodorhynchus leari Bonaparte 1856. A diploid number of 2n = 70 and a karyotype similar to that of its congener Anodorhynchus hyacinthinus suggests that chromosomal rearrangements were not the main evolutionary mechanism in the genus.

Resumo em Inglês:

We investigated four orchids of the genus Maxillaria (M. discolor, M. acicularis, M. notylioglossa and M. desvauxiana) in regard to the position of heterochromatin blocks as revealed using chromomycin A3 (CMA) and 4'-6-diamidino-2-phenylindole (DAPI) fluorochrome staining and 5S and 45S rDNA sites using fluorescence in situ hybridization (FISH). The species showed differences in chromosome number and a diversified pattern of CMA+ and DAPI+ bands, including heteromorphism for CMA+ bands. The 5S and 45S rDNA sites also varied in number and most of them were co-localized with CMA+ bands. The relationship between 5S rDNA sites and CMA+ bands was more evident in M. notylioglossa, in which the brighter CMA+ bands were associated with large 5S rDNA sites. However, not all 5S and 45S rDNA sites were co-localized with CMA+ bands, probably due to technical constraints. We compare these results to banding data from other species and suggest that not all blocks of tandemly repetitive sequences, such as 5S rDNA sites, can be observed as heterochromatin blocks.

Resumo em Inglês:

The genus Arachis currently comprises 69 described species, some of which have potential and real value as human and animal foods. These Arachis species have been collected and maintained in germplasm banks to provide material that can be used as sources of genes in breeding programs and for the selection of new cultivars. One of the principal objectives of germplasm conservation is the evaluation of genetic variability, which is best conducted using molecular markers. We investigated the use of heterologous primers to amplify microsatellite loci that could be used to evaluate genetic variability in Arachis germplasm. Fifteen microsatellite primer pairs were tested in 76 accessions of 34 species from the nine Arachis sections. The data indicated that heterologous primers were very useful in Arachis since they had high transferability among the species (91%) and allowed the amplification of very polymorphic putative loci, which allowed both the characterization of most accessions and to make inferences about the mating systems of some species analyzed. Our data also revealed that the germplasm analyzed showed high variability, even when represented by few accessions.

Resumo em Inglês:

The rice (Oryza sativa) breeding program of the Rice and Bean research center of the Brazilian agricultural company Empresa Brasileira de Pesquisa Agropecuária (Embrapa) is well established and provides new cultivars every year to attend the demand for improved high yielding varieties with tolerance to biotic and abiotic stresses. However, the elite genitors used to compose new populations for selection are closely related, contributing to the yield plateau reached in the last 20 years. To overcome this limit, it is necessary to broaden the genetic basis of the cultivars using diverse germplasm such as wild relatives or traditional varieties, with the latter being more practical because they are more easily crossed with elite germplasm to accelerate the recovery of modern plant types in the breeding lines. The objective of our study was to characterize the allelic diversity of 192 traditional varieties of Brazilian rice using 12 simple sequence repeat (SSR or microsatellite) markers. The germplasm was divided into 39 groups by common name similarity. A total of 176 alleles were detected, 30 of which (from 23 accessions) were exclusive. The number of alleles per marker ranged from 6 to 22, with an average of 14.6 alleles per locus. We identified 16 accessions as a mixture of pure lines or heterozygous plants. Dendrogram analysis identified six clusters of identical accessions with different common names and just one cluster with identical accessions with the same common name, indicating that SSR markers are fundamental to determining the genetic relationship between landraces. A subset of 24 landraces, representatives of the 13 similarity groups plus the 11 accessions not grouped, was the most variable set of genotypes analyzed. These accessions can be used as genitors to increase the genetic variability available to rice breeding programs.

Resumo em Inglês:

The genetic diversity and phylogenetic relationships in the genus Secale L. (rye) was evaluated using 24 Secale cereale microsatellite (SCM) markers. The average polymorphism information content (PIC) value of each microsatellite locus in 30 Secale accessions evaluated was higher than that in 47 cultivated ryes (Secale cereale ssp. cereale). The mean genetic similarity (GS) index in Secale was lower than that in cultivated rye. The highest within-species GS index was observed for S. sylvestre and the lowest for S. strictum, whereas the highest between-species GS index was found between S. cereale and S. vavilovii and the lowest between S. sylvestre and S. cereale. There was no obvious difference in GS levels in the cultivated rye accessions from Asia, Europe, North America or South America. Cluster analysis indicated that all the Secale accessions could be distinguished by the 24 microsatellite loci. We also found that the S. sylvestre accessions were obviously divergent from the accessions of other species and that the S. vavilovii accessions were closely related to the S. cereale accessions. Our results also showed that S. strictum was heterogeneous and showed great within-species differences. The microsatellite-derived dendrogram faithfully reflected the phylogenetic relationships between Secale species but did not indicate a possible domestication process of the cultivated rye based on the geographical sources of the accessions.

Resumo em Inglês:

Genetic similarity among soybean genotypes was studied by applying the amplified fragment length polymorphism (AFLP) technique to 317 soybean cultivars released in Brazil from 1962 to 1998. Genetic similarity (GS) coefficients were estimated using the coefficient of Nei and Li (Nei and Li 1979), and the cultivars were clustered using the unweighted pair-group method with averages (UPGMA). The parentage coefficients of 100 cultivars released between 1984 and 1998 were calculated and correlated with the genetic similarity obtained by the markers. The genetic similarity coefficients varied from 0.17 to 0.97 (x = 0.61), with 56.8% of the coefficients being above 0.60 and only 9.7% equal to or less than 0.50. The similarity coefficients have remained constant during the last three decades. Dendrogram interpretation was hindered by the large number of cultivars used, but it was possible to detect groups of cultivars formed as expected from their genealogy. Another dendrogram, composed of 63 cultivars, allowed a better interpretation of the groups. Parentage coefficients among the 100 cultivars varied from zero to one (x = 0.21). However, no significant correlation (r = 0.12) was detected among the parentage coefficients and the AFLP genetic similarity. The results show the efficiency of AFLP markers in large scale studies of genetic similarity and are discussed in relation to soybean breeding in Brazil.

Resumo em Inglês:

We report the nucleotide sequences of three citrus viroids belonging to three different genera: Citrus exocortis viroid (CEVd), Hop stunt viroid (HSVd) and Citrus viroid-III (CVd-III) isolated from a single natural infected Citrus reticulata var. Clementine tree growing in a tree nursery in Manouba (near Tunis Capital). We describe the sequence variability of these viroids from their natural host without using an alternative passage by an indicator host or an artificial inoculation. This work confirms that naturally occurring viroid infections contain a mixture of sequence variants. These are the first sequences of citrus viroids from Africa.

Resumo em Inglês:

Microsporogenesis was analyzed in an interspecific hybrid between an artificially tetraploidized sexual accession of Brachiaria ruziziensis (R genome) and a natural apomictic tetraploid accession of B. brizantha (B genome). Chromosomes associated predominantly as bivalents. From this phase to the end of meiosis, chromosomes presented irregular segregation and abnormal arrangement in the metaphase plate. During metaphase I, in 27.8% of meiocytes, bivalents were distributed in two metaphase plates. In anaphase I, two distinct and typical bipolar spindles were formed. In 29.7% of pollen mother cells, one genome did not divide synchronically, with chromosomes lagging behind or not segregating at all. The second division was very irregular, resulting in polyads. Based on previous results from analysis of a triploid hybrid between these species, where the R genome was eliminated by asynchrony during meiosis, it is suggested that the laggard genome in this hybrid also belongs to B. ruziziensis.

Resumo em Inglês:

Amplified fragment length polymorphism (AFLP) was used to investigate polymorphism among 43 Hirsutella thompsonii isolates (33 from Thailand) obtained from various mite species. The outgroups were an unidentified Hirsutella isolate along with Hirsutella nodulosa and Hirsutella kirchneri. Phylogenetic analyses of the AFLP data showed significant variation among isolates and the existence of three H. thompsonii clades. We also investigated the isolates using PCR with specific primers for the Hirsutella exotoxin gene Hirsutelin A (HtA) and 18 of these isolates were used for sequencing of the partial beta-tubulin gene. Phylogenetic analyses of beta-tubulin sequences showed two distinct H. thompsonii clades, one of which included AFLP clades I and II. For both markers grouping of the H. thompsonii isolates was not related to either host mite species or geographical origin, although for the HtA gene one clade contained only isolates with no detectable HtA band. These results confirm the high intraspecific polymorphism of H. thompsonii, and maximum likelihood analysis showed no monophyletic group within this species. To refine the taxonomy of this genus other studies should be undertaken using additional molecular markers and several other Hirsutella isolates.

Resumo em Inglês:

The Gram-negative bacterium Pseudomonas aeruginosa has a wide environmental and ecological distribution. It is an opportunistic pathogen that acquires resistance to multiple antimicrobial agents and can infect plants, animals and humans. We used rDNA and tDNA PCR markers to characterize the bacterial diversity of P. aeruginosa strains isolated at a Brazilian teaching hospital (Oswaldo Cruz University Hospital, Recife, Brazil) between March 2003 and February 2004. Clonal groups of P. aeruginosa clinical isolates were identified from different patients in different hospital units using either rDNA or tDNA markers, or a combination of both in a duplex PCR. These PCR-typing methods together with drug-resistance profiles were used to trace the distribution of antibiotic resistant P. aeruginosa clones and to identify cross-infection of the same patient with a different bacterial clone after being moved to a different hospital unit. The data presented here demonstrates a rapid, reliable and useful method for epidemiological surveillance that can contribute to the control of P aeruginosa infections in hospital environments.

Resumo em Inglês:

Polyphenols are potent antioxidants that are particularly abundant in the Mediterranean diet, with olive oil being the main fat source. A number of investigations have reported that phenolic compounds found in dietary oils are antioxidants and could provide protective effects by inhibiting DNA oxidative damage. However, few studies have been published on the biological activity of vegetable oils, including their possible mutagenic/antimutagenic effects. The objective of the current study was to investigate the cytogenetic effects of multiple doses of four vegetable oils in rat bone marrow cells and to examine the possible antimutagenic effects of these oils in chromosomal damage induced by the antitumor drug cisplatin. These oils are consumed by humans and commonly used as drug vehicles. The rats received treatment with multiple doses of canola oil, olive oil, virgin olive oil, and corn oil (5 mL kg-1) alone or combined with the antitumor drug cisplatin (5 mg kg-1). Treatments with vegetable oils alone did not increase the percentage of cells with chromosomal aberrations (p > 0.05). Olive, virgin olive and canola oils showed protective effects against cisplatin-induced chromosomal damage (p < 0.05). A rational mechanism for the protective effects of vegetable oils is that their phenolic compounds have antioxidant and antimutagenic properties in vivo.

Resumo em Inglês:

We used microsatellite loci to test the paternity of two male jaguars involved in an infanticide event recorded during a long-term monitoring program of this species. Seven microsatellite primers originally developed for domestic cats and previously selected for Panthera onca were used. In order to deal with uncertainty in the mother's genotypes for some of the loci, 10000 values of W were derived by simulation procedures. The male that killed the two cubs was assigned as the true sire. Although the reasons for this behavior remain obscure, it shows, in principle, a low recognition of paternity and kinship in the species. Since the two cubs were not very young, one possibility is that the adult male did not recognize the cubs and killed them for simple territorial reasons. Thus, ecological stress in this local population becomes a very plausible explanation for this infanticide, without further sociobiological implications.

Resumo em Inglês:

Transposable elements (TEs) are middle repetitive DNA sequences classified into families according to their sequence similarities, such elements can playing an important role in the evolutionary process of their host genomes. There are many reports on the distribution of TEs in the fruit fly genus Drosophila, although there is relatively little information relating to the Neotropical mesophragmatica group of Drosophila, probably the most typical cluster of species occurring almost exclusively in the Andes mountains. Dot Blot and PCR analyses was used to study the distribution of some TEs (I, mariner, hobo, gypsy, Tom/17.6, micropia and P elements) within the mesophragmatica group of Drosophila. We found gypsy elements in all the mesophragmatica group species studied and mariner elements were absent only from Drosophila pavani but P element homologous sequences were present only in D. pavani and Drosophila gasici and the other TEs (I, hobo, Tom/17.6, micropia) were not found in any of the species investigated.

Resumo em Inglês:

Restriction fragment length polymorphism of whole mitochondrial DNA or PCR amplified mtDNA regions are known to be useful in discriminating among honey bee lineages and also some individual subspecies. In this study, PCR-amplified fragments of cytochrome oxidase I (CO-I) and cytochrome B (Cyt B) of honey bees sampled from different countries (Cyprus, Turkey, Ethiopia, Syria and Egypt) were digested with Hinf I and Bgl II restriction enzymes, respectively. Eastern Europe and Mediterranean honey bee subspecies were separated by the Cyt B/Bgl II analysis, although Hinf I digestion of the CO-I region yielded much finer resolution within different honey bee lineages. Here we report that CO-I/Hinf-I is a discriminative test for the mitochondrial "O" lineage, rather than a diagnostic site for A. m. lamarckii.

Resumo em Inglês:

The muriqui (Brachyteles) is one of the most endangered primates in the world, however little is known about the viability of the remaining populations. We evaluated the technique of extracting DNA from wild muriqui feces for PCR applications. In order to determine the effect of the DNA in subsequent amplifications, we analyzed five different extracts. The importance of the recommended BSA and the HotStarTaq DNA polymerase was tested. The minimal conditions to successfully amplify highly degraded fecal DNA were determined, showing that the recommended reagents are not required. We envision that this method may be useful in further conservation management studies.

Resumo em Inglês:

The multidrug resistance (MDR) phenotype is associated with the expression of P-glycoprotein (Pgp), coded by the multigenic mdr family. Mice present the isoforms mdr1 and mdr3, which are responsible for multidrug resistance, and mdr2, that is involved in the transport of phospholipids. mdr1 expression has more recently been associated also with the secretion of steroid hormones. This work presents an RT-PCR analysis of the expression of mdr isoforms, in several organs of mice during different phases of the estrous cycle. Additionally, females were ovariectomized, submitted to different hormone treatments, and their uterus was analyzed for the expression of mdr isoforms. The results show that in the adrenal gland and ovaries mdr1 is the main isoform during proestrus, and that progesterone or a combination of progesterone and estrogen induce the expression of all mdr isoforms in the uterus of ovariectomized females. We suggest that the functions of mdr1 and mdr3 are overlapping, that mdr3 may be the more efficient isoform in the detoxification function, and that mdr1 may be more closely related to the secretion of steroid hormones.

Resumo em Inglês:

With the advent of structural genomics, the need for fast structural information about unknown proteins has increased. We describe a new methodology, based on 13C, 15N and ¹H chemical shift dispersion to predict the amount of secondary structure of unassigned proteins from their 15N- and/or 13C-edited heteronuclear single quantum coherence (HSQC) spectra. This methodology has been coded into a software called PASSNMR (Prediction of the Amount of Secondary Structure by Nuclear Magnetic Resonance), which can be accessed directly from the Internet. PASSNMR program is a powerful tool for screening proteins for proteomic or structural genomic investigations when used with recent methodologies that take advantage of the use of the antibiotic rifampicin to selectively label the heterologous proteins expressed in E. coli. PASSNMR analysis can be useful as a first approach to predict the amount of secondary structure in proteins to structural genomics. Information about the secondary structure of proteins can be obtained even before protein purification, with small quantities of protein, just by performing two simple nuclear magnetic resonance (NMR) experiments and using PASSNMR program.