bluuebunny/crossref_metadata_2025 huggingface dataset:
Anticlastogenic effect of vitamin C on cisplatin in vivo
Authors: Antunes Lusânia M. Greggi , Darin Joana D.C. , Bianchi Maria de Lourdes P.
Published: April 2005

The ability of vitamin C (VC) to protect against the clastogenic action of the chemotherapeutic agent cisplatin (DDP, cis-diamminedichloroplatinun II) in rat bone marrow cells was evaluated. DDP was administered to Wistar rats either alone or after treatment with VC. The rats were treated with VC (50, 100 or 200 mg/kg body weight) by gavage 10 min before the administration of DDP (5 mg/kg body weight, ip) and then sacrificed 24 h after treatment. VC significantly reduced (by about 70%) the clastogenicity of DDP in rat bone marrow cells. The antioxidant action of VC presumably modulates the clastogenic action of DDP.
Genetic divergence among common bean cultivars from different races based on RAPD markers
Authors: Duarte Jair Moura , Santos João Bosco dos , Melo Leonardo Cunha
Published: April 2005

The genetic divergence of 27 common bean (Phaseolus vulgaris L.) cultivars from different races was evaluated using RAPD markers. The association of this divergence with some indirect variability estimates obtained in field experiments was also assessed. Genetic distances were calculated using Sorensen-Dice's similarity coefficient, displayed in a dendrogram (UPGMA method), and by projection in two-dimensional space. Analysis of molecular variance (AMOVA) was used to evaluate the distribution of variance between and within domestication centers. RAPD marker genetic diversity within these centers was also calculated. The correlations between estimates of genetic distances obtained with RAPD markers and estimates of Mahalanobis' generalized distances, specific combination ability, and midparent heterosis obtained from morpho-agronomical traits were also determined. RAPD markers were efficient in separating cultivars according to domestication centers. However, only for Middle American domestication center was there good agreement between the grouping obtained and the proposed classification of races. The genetic divergence obtained with these markers was similar to that provided by morpho-agronomical traits. RAPD markers, however, were not efficient in predicting the specific combination ability and midparent heterosis expressed in crosses.
Chromosomal polymorphism in 12 populations of Mikania micrantha (Compositae)
Authors: Maffei Eliane M.D. , Marin-Morales M.A. , Ruas P.M. , Ruas C.F. , Matzenbacher N.I.
Published: April 2005

Mikania micrantha is a climbing perennial weed of the family Asteraceae, with a vast distribution from South America to south of the United States. This species is widely distributed throughout Brazil, where it shows little morphological variation. Mitotic chromosomes of 12 populations of M. micrantha derived from several Brazilian sites were studied using Feulgen staining and C-banding. The populations included eight diploid (2n = 36 and 42) and four tetraploid (2n = 72) cytotypes. Chromosome numbers of 2n = 36 and 2n = 42 are reported for the first time for M. micrantha. These populations had a secondary constriction in the middle of the larger arm of chromosome pair 1, following the same pattern described for all Mikania species analyzed so far. Numerical and structural variation of the chromosomes was quite common among the karyotypes and nearly all cytotypes differed from each other in some aspect. Most of the chromosomal differentiation may be attributed to inversions and addition or deletion of DNA fragments. C-banding, applied to three of the 12 populations, also revealed polymorphism in the distribution of heterochromatin. Additionally, one to 14 supernumerary or B-chromosomes were observed. The Bs were detected in six of the 12 populations and varied in size, number, and structure among karyotypes and also among cells of the same root meristem. The B chromosomes were also heterochromatic, showing a C-banding pattern similar to the A chromosomes, and suggesting that they may be derived from the chromosomes of the A complement.
Expression of a methionine-rich storage albumin from the Brazil nut (Bertholletia excelsa H.B.K., Lecythidaceae) in transgenic bean plants (Phaseolus vulgaris L., Fabaceae)
Authors: Aragão F.J.L. , Barros L.M.G. , Sousa M.V. de , Grossi de Sá M.F. , Almeida E.R.P. , Gander E.S. , Rech E.L.
Published: April 2005

Bean (Phaseolus vulgaris), an important component in the diet of people in developing countries, has low levels of the essential amino acid, methionine. We have attempted to correct this deficiency by introducing a transgene coding for a methionine-rich storage albumin from the Brazil nut via biolistic methods. The transgene's coding sequence was driven by a doubled 35S CaMV promoter and AMV enhancer sequences. The transgene was stable and correctly expressed in homozygous R2 to R5 seeds. In two of the five transgenic lines the methionine content was significantly increased (14 and 23%) over the values found in untransformed plants.
Lapa vermelha IV Hominid 1: morphological affinities of the earliest known American
Authors: Neves Walter A. , Powell Joseph F. , Prous Andre , Ozolins Erik G. , Blum Max
Published: April 2005

Several studies concerning the extra-continental morphological affinities of Paleo-Indian skeletons, carried out independently in South and North America, have indicated that the Americas were first occupied by non-Mongoloids that made their way to the New World through the Bering Strait in ancient times. The first South Americans show a clear resemblance to modern South Pacific and African populations, while the first North Americans seem to be at an unresolved morphological position between modern South Pacific and Europeans. In none of these analyses the first Americans show any resemblance to either northeast Asians or modern native Americans. So far, these studies have included affirmed and putative early skeletons thought to date between 8,000 and 10,000 years B.P. In this work the extra-continental morphological affinities of a Paleo-Indian skeleton well dated between 11,000 and 11,500 years B.P. (Lapa Vermelha IV Hominid 1, or "Luzia") is investigated, using as comparative samples Howells' (1989) world-wide modern series and Habgood's (1985) Old World Late Pleistocene fossil hominids. The comparison between Lapa Vermelha IV Hominid 1 and Howells' series was based on canonical variate analysis, including 45 size-corrected craniometric variables, while the comparison with fossil hominids was based on principal component analysis, including 16 size-corrected variables. In the first case, Lapa Vermelha IV Hominid 1 exhibited an undisputed morphological affinity firstly with Africans and secondly with South Pacific populations. In the second comparison, the earliest known American skeleton had its closest similarities with early Australians, Zhoukoudian Upper Cave 103, and Taforalt 18. The results obtained clearly confirm the idea that the Americas were first colonized by a generalized Homo sapiens population which inhabited East Asia in the Late Pleistocene, before the definition of the classic Mongoloid morphology.
Analysis of mRNA transcripts in chronic myeloid leukemia patients
Authors: Meissner Rosely de V. , Covas Dimas T. , Dias Paula M.B. , Job Fani , Leite Márcia , Nardi Nance B.
Published: April 2005

The nature of BCR/ABL hybrid mRNA was analyzed by RT-PCR in cells from 33 patients (22 males, 11 females) with chronic myeloid leukemia (CML). b3a2 mRNA was found in 14 cases, whereas 13 patients had b2a2 mRNA and six had both kinds of mRNA, with a predominance of the b3a2 type. The type of mRNA present showed no significant correlation with age, hemoglobin level, number of leukocytes and platelets, percentage of blasts or basophils or the presence of splenomegaly at diagnosis. There was also no correlation with sex or duration of the chronic phase. When these results were combined with those reported by other groups, a significant association (P = 0.029) was observed for mRNA type vs. sex, with a predominance of men in the groups expressing b2a2 (2.68:1) and b3a2 (1.33:1). We conclude that the classification of patients according to mRNA type does not homogenize the clinical and hematological data within groups, where variance is large, nor does it allow a differentiation between groups.
Evidence for biological inheritance of the eosinophil response to internal parasites in southeastern Brazil
Authors: Conti Fátima , Dal' Colletto Glória M. Duccini , Feitosa Mary Furlan , Krieger Henrique
Published: April 2005

One hundred and seventy-seven individuals belonging to 120 complete or incomplete nuclear families from Bambui, in the State of Minas Gerais, southeastern Brazil, were studied in order to examine causes of variation in the eosinophil rate among subjects infested by intestinal worms with an extra-digestive cycle. Segregation analysis without correction for skewness showed that the hypothesis of the presence of an additive major gene was consistent with the data, although a dominant, recessive, or a multifactorial hypothesis could not account properly for the observed significant familial aggregation. The most parsimonious correction for skewness showed similar results, but could not distinguish between dominant and recessive models, although co-dominance was rejected. Since these models assume that skewness was attributable to the commingling of two distributions, these results seem to agree with those for uncorrected data. These findings suggest that several genetically independent factors determine the resistance/susceptibility to helminth infestation mainly through their ability to influence the eosinophil response.
Clinical and molecular analysis of spinal muscular atrophy in Brazilian patients
Authors: Kim C.A. , Passos-Bueno M.R. , Marie S.K. , Cerqueira A. , Conti U. , Marques-Dias M.J. , Gonzalez C.H. , Zatz M.
Published: April 2005

Spinal muscular atrophy (SMA), the second most common lethal autosomal recessive disorder, has an incidence of 1:10,000 newborns. SMA is divided into acute (Werdnig-Hoffmann disease, type I), intermediate (type II) and juvenile forms (Kugelberg-Welander disease, type III). The gene of all three forms of SMA maps to chromosome 5q 11.2-13.3. Two candidate genes, the survival motor neuron (SMN) gene and the neuronal apoptosis inhibitory protein (NAIP) gene, have been identified; SMN is deleted in most SMA patients. We studied both genes in 87 Brazilian SMA patients (20 type I, 14 type II and 53 type III) from 74 unrelated families, by using PCR and single strand conformation polymorphism (SSCP). Deletions of exons 7 and/or 8 of the SMN gene were found in 69% of the families: 16/20 in type I, 9/12 in type II and 26/42 in type III. Among 51 families with deletions, 44 had both exons deleted while seven had deletions only of exon 7. Deletions of exon 5 of the NAIP gene were found in 7/20 of type I, 2/12 of type II and 1/42 of type III patients. No deletion of SMN and NAIP genes was found in 112 parents, 26 unaffected sibs and 104 normal controls. No correlation between deletions of one or both genes and phenotype severity was found.
Genetic structure of different cat populations in Europe and South America at a microgeographic level: importance of the choice of an adequate sampling level in the accuracy of population genetics interpretations
Authors: Ruiz-Garcia Manuel
Published: April 2005

The phenotypic markers, coat color, pattern and hair length, of natural domestic cat populations observed in four cities (Barcelona, Catalonia; Palma Majorca, Balearic Islands; Rimini, Italy and Buenos Aires, Argentina) were studied at a microgeographical level. Various population genetics techniques revealed that the degree of genetic differentiation between populations of Felis catus within these cities is relatively low, when compared with that found between populations of other mammals. Two different levels of sampling were used. One was that of "natural" colonies of cat families living together in specific points within the cities, and the other referred to "artificial" subpopulations, or groups of colonies, inhabiting the same district within a city. For the two sampling levels, some of the results were identical: 1) little genic heterogeneity, 2) existence of panmixia, 3) similar levels of expected heterozygosity in all populations analyzed, 4) no spatial autocorrelation, with certain differentiation in the Buenos Aires population compared to the others, and 5) very high correlations between colonies and subpopulations with the first factors from a Q factor analysis. Nevertheless, other population genetic statistics were greatly affected by the differential choice of sampling level. This was the case for: 1) the amount of heterogeneity of the FST and GST statistics between the cities, which was greater at the subpopulation level than at colony level, 2) the existence of correlations between genic differentiation statistics and size variables at subpopulation level, but not at the colony level, and 3) the relationships between the genetic variables and the principal factors of the R factorial analysis. This suggests that care should be taken in the choice of the sampling unit, for inferences on population genetics to be valid at the microgeographical level.
Genetic variability in five species of Anostomidae (Ostariophysi - Characiformes)
Authors: Chiari Lucimara , Sodré Leda Maria Koelblinger
Published: April 2005

Genetic variability was studied in five fish species (Anostomidae): Schizodon intermedius and S. nasutus and Leporinus friderici, L. elongatus and L. obtusidens, collected at one location on the Tibagi River (Paraná, Brazil). The protein data from seven systems coded collectively for 19 loci in the liver, muscle and heart. Nine of these loci were polymorphic. The estimated proportion of polymorphism loci () varied from 16.7% in S. intermedius to 36.9% in L. friderici; the mean heterozygosity observed (o) was 0.027 ± 0.015 and 0.109 ± 0.042, respectively. The estimated value of the genetic identity among L. friderici and S. intermedius (0.749) and S. nasutus (0.787) suggested that these are "congeneric" species. Morphological characteristics indicate that these species belong to distinct genera, while isoenzymatic data show that they are very similar at the genetic/biochemical level.
Selection for breed-specific growth hormone and IGF-I alleles in a synthetic beef cattle cross, Canchim
Authors: Regitano L.C.A. , Azevedo J.L. , Vencovsky R. , Packer I.U. , Barbosa P.F. , Rosa A.J.M. , Silva N.A. , Etchegaray M.A.L. , Coutinho L.L.
Published: April 2005

This study was developed to evaluate selection effects on gene frequencies in a synthetic beef cattle cross (5/8 Charolais, 3/8 Zebu) named Canchim. A sample of 154 Canchim animals, representing three generation classes, was analyzed for seven molecular markers. Thirty-six Charolais cattle were also studied for comparison. A highly significant variation (P < 0.01), with a linear increase of the allele coding for valine at position 127 of the growth hormone peptide, was observed through generations. This allele was found in the Charolais sample but is not observed in Brazilian Bos indicus breeds. Four alleles were found for a microsatellite in the 5' flanking region of insulin-like growth factor I gene in Canchim. Allele sizes ranged from 231 to 225 bp. There was a significant (P < 0.05) nonlinear increase in the 225-bp allele frequency. This allele was not observed in Charolais. Six alleles were observed for microsatellite CSFM50 in the Canchim population. A significant (P < 0.05) linear reduction of the 168-bp allele was observed over the generations. The hypothesis of preferential mating for growth hormone polymorphism was supported by Wright's F-statistics. Estimated FIS value for growth hormone was 0.59 (P < 0.01). These results suggest that selection influenced three out of seven loci analyzed. The simultaneous increases of a Bos taurus-specific growth hormone allele and a Bos indicus-specific insulin-like growth factor I allele indicate that phenotypic selection favored different regions of both genomes.
k-Casein, b-lactoglobulin and growth hormone allele frequencies and genetic distances in Nelore, Gyr, Guzerá, Caracu, Charolais, Canchim and Santa Gertrudis cattle
Authors: Kemenes Paola Augusta , Regitano Luciana Correia de Almeida , Rosa Artur Jordão de Magalhães , Packer Irineu Umberto , Razook Alexander George , Figueiredo Leopoldo Andrade de , Silva Nirlei Aparecida , Etchegaray Maria Antônia L. , Coutinho Luiz Lehmann
Published: April 2005

The genotypes for k-casein (k-CN), b-lactoglobulin (b-LG) and growth hormone (GH) were determined by polymerase chain reaction (PCR) and restriction enzyme digestion in seven breeds of cattle (Nelore, Gyr, Guzerá, Caracu, Charolais, Canchim and Santa Gertrudis). k-Casein had two alleles with the A allele occurring at a higher frequency in Bos indicus breeds (0.93, 0.92 and 0.91% for Gyr, Guzerá and Nelore, respectively). The b-lactoglobulin locus had two alleles in all of the breeds. European breeds had a higher frequency of the b-LG A allele than Zebu breeds. The GH locus had two alleles (L and V) in Bos taurus and was monomorphic (L allele only) in all of the Bos indicus breeds evaluated. The highest frequency for the V allele was observed in Charolais cattle. The markers used revealed a considerable similarity among breeds, with two main groups being discernible. One group consisted of Zebu and Santa Gertrudis breeds and the other consisted of European and Canchim breeds.
Is the American Zebu really Bos indicus?
Authors: Meirelles Flávio V. , Rosa Artur J.M. , Lôbo Raysildo B. , Garcia Joaquim M. , Smith Lawrence C. , Duarte Francisco A.M.
Published: April 2005

The American continent was colonized in the 16th century by Europeans who first introduced cattle of Bos taurus origin. Accounts register introduction of Bos indicus cattle into South America in the 19th and continuing through the 20th century, and most reported imports were males derived from the Indian subcontinent. In the present study we show, by using mitochondrial DNA (mtDNA) polymorphism, major participation of matrilineages of taurus origin in the American Zebu purebred origin, i.e., 79, 73 and 100% for the Nellore, Gyr and Brahman breeds, respectively. Moreover, we have created a restriction map identifying polymorphism among B. taurus and B. indicus mtDNA using three restriction enzymes. Results are discussed concerning American Zebu origins and potential use of this information for investigating the contribution of cytoplasmic genes in cattle production traits.
Muscle biopsy technique for electrophoresis analysis of fish from the genus Brycon
Authors: Hilsdorf Alexandre , Caneppele Danilo , Krieger José Eduardo
Published: April 2005

Protein and mitochondrial DNA have been used as molecular markers to assess variability in stock identification studies of fishes. Protein and mtDNA used for electrophoretic analysis are extracted from tissues, which often leads to death of the individuals. In this study, we present a skeletal muscle biopsy procedure to extract mitochondrial DNA that does not require specimen sacrifice. Eighty pirapitinga-do-sul (Brycon opalinus) were biopsied by the present technique, with no mortalities recorded. Total DNA was extracted from muscle and digested by restriction enzymes ApaI and HpaI. The mtDNA fragment patterns were hybridized with 32P-labeled pirapitinga-do-sul mtDNA probes. The described technique is simple and may be useful in protocols requiring tissue extraction for DNA and protein analyses without loss of the individual investigated.
Chromosomal characterization of three native and one cultivated species of Lathyrus L. in Southern Brazil
Authors: Battistin Alice , Biondo Elaine , Coelho Liliana Gressler May
Published: April 2005

Mitotic metaphase chromosomes and interphase nuclei of nine populations of three South American species of Lathyrus (L. pubescens, L. nervosus and L. crassipes) and six populations of the cultivated species L. odoratus were analyzed. All populations had 2n = 2x = 14 chromosomes. There were significant differences among populations within each species and among species in the number of metacentric, submetacentric and subtelocentric chromosomes, the number and location of secondary constrictions, chromosome length (longest and shortest), total haploid complement, arm ratio, and centromeric index. L. odoratus showed the highest tendency towards karyotype symmetry whereas the three South American species showed a moderate tendency towards asymmetry, with L. pubescens being the most asymmetrical. Silver staining was used to identify the nucleolar organizer regions (NORs) and the number of nucleoli per interphase nucleus in each species. In L. pubescens and L. nervosus, the NORs were located on the secondary constriction of the long arm of pair 7, in L. crassipes, the NOR was proximal being located in the pair of metacentric chromosomes, and in L. odoratus there were four terminal NORs on the short arms of pairs 4 and 5. The four species had a maximum of four nucleoli per interphase nucleus, indicating the presence of four regions with active ribosomal genes in each case.
Combining ability of Phaseolus vulgaris L. for resistance to common bacterial blight
Authors: Rodrigues Rosana , Leal Nilton Rocha , Pereira Messias Gonzaga , Lam-Sánchez Alfredo
Published: April 2005

Many diseases limit dry bean and snap bean yields. Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli, is one of the most serious bacterial diseases in dry bean and snap bean that cause crop losses. Since there is no satisfactory chemical control, the use of resistant cultivars is an important control measure. Genetic studies of resistance are important for choosing appropriate breeding methods. Combining ability was determined for disease resistance in three snap bean genotypes (Alessa, Hab 52 and Hab 198) and two dry bean genotypes (Bac-6 and A-794). Plants were inoculated with highly pathogenic isolate CNF 15, using a razor blade procedure in leaves and needle punctures in pods. They were evaluated 7 days after inoculation. Leaves were evaluated on a 1 to 5 scale and pods by lesion diameter. Diallel analysis was conducted using Griffing's model. General combining ability (GCA) was significant for both leaf and pod infection, whereas specific combining ability (SCA) was significant for disease reaction in pods. Bac-6 and A-794 were considered superior genotypes for leaf resistance. Nonadditive effects were predominant in pod reactions, and Alessa x Bac-6, Alessa x A-794 and Hab 52 x Bac-6 were the best combinations.
Genetic control of plant architecture in the common bean (Phaseolus vulgaris L.)
Authors: Teixeira Flavia França , Ramalho Magno Antonio Patto , Abreu Ângela de Fátima Barbosa
Published: April 2005

More erect plant architecture has been a goal in the development of bean cultivars. Aiming to obtain more information about genetic control of traits related to plant architecture, this work was carried out between August 1995 and July 1997 in the southern and Alto São Francisco regions, in the State of Minas Gerais, Brazil. Initially, analyses were performed with individual plants of parents and different segregant generations from the crosses Carioca-MG x H-4 and Carioca x FT-Tarumã. In these experiments, besides degree of erectness, other traits were evaluated: ramification degree, internode length, internode diameter and height of insertion of the first pod. Mean and variance components and heritability at an individual level were estimated. Later, families derived from F2 or F3 plants of the same crosses were evaluated for degree of erectness. Genetic and phenotypic variance between family averages, heritabilities using variance components, and realized heritability were estimated. Of the morphological traits, internode length varied the most. There was a predominance of additive effect in the control of this trait. Evaluating plant architecture with individual plants for degree of erectness was not efficient. However, when families were used, genetic parameter estimates confirmed the possibility of successful selection, especially if evaluated for a few generations and/or environments, despite the strong environmental influence on trait expression.
Genetics of anthracnose panel canker disease resistance and its relationship with yield and growth characters in half-sib progenies of rubber tree (Hevea brasiliensis)
Authors: Gonçalves Paulo de Souza , Furtado Edson Luiz , Bataglia Ondino Cleante , Ortolani Altino Aldo , May André , Belletti Giselle Olmos
Published: April 2005

Rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell-Arg] anthracnose panel canker disease resistance, caused by Colletotrichum gloeosporioides (Penz.) Sacc., and growth and yield characters were assessed at three years old in the nursery, in 18 half-sib progenies. There were highly significant (P < 0.01) genetic differences among progenies for most characters. The genetic component of variance accounted for 3.37, 6.07, 12.74, 12.13, 19.82 and 3.58% of the phenotypic variance for anthracnose-infected area, anthracnose lesion stripe length, yield, girth, virgin bark thickness and total number of latex vessel rings, respectively. Narrow-sense heritability estimates for the above characters were 13.45, 24.30, 50.97, 48.52, 79.30 and 14.30%, respectively. No significant genetic correlations were found among anthracnose panel canker resistance, yield and growth characters. The frequency distribution of anthracnose-infected area and anthracnose lesion stripe length suggests polygenic control. Selecting the best three progenies out of 18 progenies would result in a genetic gain of 12.87 and 24.24% for infected area and lesion stripe length, respectively. The best five selected individuals out of 50 individuals within each progeny would result in a genetic gain of 9.47 and 24.62%, with a total gain of 22.34 and 48.87% for these two characters, respectively.
Identification of resistant genotypes considering polygenic systems in host-pathogen interaction
Authors: Melo Leonardo Cunha , Santos João Bosco dos
Published: April 2005

Plant resistance to pathogens is the most efficient form of disease control. However, identification of resistant genotypes is often difficult, especially when the genetic basis for the host-pathogen relationship is unknown. This study was carried out to test a methodology capable of providing, in a simple way, information about host vertical and horizontal resistance as well as pathogen virulence. A simulation using twenty, ten, and five pathogen races and twenty hosts was carried out. Host reaction was controlled by ten genes with two alleles each. Eight genes had little effects, one had medium and the other strong effects. Genetic control of pathogenicity was identical to that of the host. Only homozygous genotypes were used for pathogens and hosts in this simulation, with no epistatic effects. Simulation was based on the expected disease severity with the inoculation of twenty hosts with twenty pathogen races, according to additive and interactive models proposed by Parlevliet and Zadoks (Euphytica 26: 5-21, 1977). Data were analyzed by model IV of Griffing, using a partial diallel scheme. A high correlation was found between general reaction ability (GRA) and potential host resistance, which proved to be an indicator of horizontal resistance. A high correlation between general aggressivity ability (GAA) and potential pathogenicity of the race also proved to be an aggressivity indicator. Specific interaction ability (SIA) is an indicator of host vertical resistance and pathogen virulence. Simulation with a lower number of races (ten and five) showed similar results. SIA was significant in both the interactive and additive models.
Numerical chromosome polymorphism in Mikania cordifolia Willd. (Asteraceae)
Authors: Maffei E.M.D. , Marin-Morales M.A. , Ruas P.M. , Ruas C.F.
Published: April 2005

Cytogenetical analysis of Mikania cordifolia, from southeastern Brazil, using the conventional Feulgen method, showed a chromosome number of 2n = 36. Previous karyotypic descriptions for this species showed a numerical chromosome variation of 2n = 34 to 38. There was a secondary constriction in every metaphase in the first chromosome pair, which constitutes a cytological marker. Small extranumerary chromosomes with numerical variation in the same plant were found in the tenth chromosome pair.
Mapping oligogenes for atopy and asthma by meta-analysis
Authors: Collins A. , Ennis S. , Tapper W. , Morton N.E.
Published: April 2005

Meta-analysis is presented for published studies on linkage or allelic association that have in common only reported significance levels. Reporting is biassed, and nonsignificance is seldom quantified. Therefore meta-analysis cannot identify oligogenes within a candidate region nor establish their significance, but it defines candidate regions well. Applied to a database on atopy and asthma, candidate regions are identified on chromosomes 6, 5, 16, 11, 12, 13, 14, 7, 20, and 10, in rank order from strongest to weakest evidence. On the other hand, there is little support for chromosomes 9, 8, 18, 1, and 15 in the same rank order. The evidence from 156 publications is reviewed for each region. With reasonable type I and II errors several thousand affected sib pairs would be required to detect a locus accounting for 1/10 of the genetic effect on asthma. Identification of regions by a genome scan for linkage and allelic association requires international collaborative studies to reach the necessary sample size, using lod-based methods that specify a weakly parametric alternative hypothesis and can be combined over studies that differ in ascertainment, phenotypes, and markers. This has become the central problem in complex inheritance.
Screening fetal losses for monosomy X with a simple PCR-based procedure
Authors: Pereira Rinaldo W. , Sturzeneker Rosane , Pena Sérgio D.J.
Published: April 2005

To screen for monosomy X in spontaneous fetal losses we explored a simple molecular strategy based on loss of heterozygosity at highly polymorphic X-linked loci. We developed a multiplex fluorescent procedure that allows the simultaneous amplification of five dinucleotide repeat polymorphisms in a large low-recombination region in the long arm of the X chromosome. Analysis was performed by computer-assisted laser densitometry. We did not find any instances of homozygosity at all five loci in 30 normal females tested, nor among 37 women whose typing data were retrieved from the Fondation Jean Dausset - CEPH genotype database. In addition, all cases of monosomy X previously diagnosed by conventional cytogenetics presented the anticipated loss of heterozygosity at all loci. We studied 19 spontaneously aborted female fetuses and we found four samples homozygous for the five loci (21%), in good agreement with the expected rate of monosomy X in first trimester spontaneous abortions. We conclude that the loci have high diversity and high efficiency in PCR-amplification and that our multiplex procedure constitutes a simple and useful molecular screening test for monosomy X in abortions and stillbirths.
Perinatal mortality among twins and singletons in a city in southeastern Brazil, 1984-1996
Authors: Beiguelman Bernardo , Franchi-Pinto Carla
Published: April 2005

Analysis of 116,699 deliveries (1062 twin pairs and 115,637 singletons) which occurred from 1984 to 1996 at the largest obstetric center in Campinas, SP, Brazil, provided the following conclusions: 1) despite the low percentage of twin births (0.9%), 10.7% of all early neonatal deaths and 3.5% of all stillbirths were twins. Compared to singletons, the likelihood of stillbirths and early neonatal deaths among twins was 1.9 and 6.5 times greater, respectively. 2) The proportion of twins among early neonatal deaths tended to decrease, probably because of improvements in prenatal and perinatal care. 3) The critical period for early neonatal deaths in singletons and twins lasted for the three first days after birth. 4) The incidence of perinatal deaths among twins was highest among MM pairs, followed by FF pairs, and lowest among MF pairs. 5) There was a trend towards a decrease in the annual rate of early neonatal deaths among both singletons and twins, and of stillbirths among singletons, the latter being more conspicuous among females. 6) The sex ratio of singletons was practically stable among living newborns, but showed strong cyclic variation among early neonatal deaths, and a tendency to increase among stillbirths. Twins who died in the first week, as well as living twins showed a strong increase in their sex ratio from 1984 to 1996. 7) The mean gestational age of singletons was highest among living newborns followed by stillbirths, and was lowest among early neonatal deaths. The mean gestational age of living twins was higher than that of early neonatal deaths, but not different from that of stillbirths. 8) The mean birth weight of singletons and twins was highest among living newborns, followed by stillbirths, and lowest among early neonatal deaths. 9) Apgar scores > or = 7 obtained five minutes after birth are inadequate as a reliable indicator of the clinical condition of the newborn, since almost half of the early neonatal deaths had 5-min Apgar scores varying from 7 to 10.
Genetic hearing loss: a study of 228 Brazilian patients
Authors: Longhitano Silvia Bragagnolo , Brunoni Décio
Published: April 2005

We studied 228 patients, with suspected or confirmed genetic hearing loss, in order to determine the clinical and genetic diagnoses and etiology of each case. Deafness with no associated abnormalities was found in 146 patients (64%) belonging to 112 families. Syndromic deafness was diagnosed in 82 patients (36%) belonging to 76 families. The genetic etiology was as follows: autosomal recessive inheritance in 40.8% of syndromics and non-syndromics, autosomal dominant inheritance in 13.2% and X-linked recessive in 1.3%. In 44.7% of the cases, the etiology of the hearing loss could not be determined. Monogenic causes are the most possible etiology in the latter cases. Parental consanguinity was found in 22.4% of the cases, and deafness was bilateral, profound and neurosensorial in 47.4% of the patients. An early onset of hearing loss (< 2 years of age) occurred in 46.5% of the cases. These results are similar to previous literature reports.
Mitochondrial DNA-like sequence in the nuclear genome of Saguinus (Callitrichinae, Primates): transfer estimation
Authors: Vallinoto Marcelo , Sena Leonardo , Sampaio Iracilda , Schneider Horacio , Schneider Maria Paula
Published: April 2005

Mitochondrial DNA-like sequences have been found in the nuclei of a variety of organisms. These nuclear pseudogenes can be used to estimate relative evolutionary rates of mitochondrial genes, and can be used as outgroups in phylogenetic analyses. In this study, mitochondrial sequences with pseudogene-like characteristics, including deletions and/or insertions and stop codons, were found in tamarins (Saguinus spp., Callitrichinae, Primates). Phylogenetic analysis allowed estimation of the timing of the migration of these sequences to the nuclear genome, and also permitted inferences on the phylogeny of the genus. The choice of an inadequate outgroup (Aotus infulatus) prevented a good phylogenetic resolution of the subfamily Callitrichinae. The relatively ancient divergence of the Cebidae (Callitrichinae, Aotinae and Cebinae) may have favored confounding homoplasies.
Population genetics of the Chilean frog Batrachyla Leptopus (Leptodactylidae)
Authors: Formas J.R. , Brieva L.M.
Published: April 2005

Electrophoretic variation of proteins encoded by 14 loci was analyzed in eight (five continental and three insular) populations of the Chilean leptodactylid frog Batrachyla leptopus. The overall proportion of polymorphic loci was estimated to be 18.7% and the average number of alleles per locus, 1.2, while observed and expected heterozygosities were 1.7 and 5.1%, respectively. The estimated coefficient of genetic identity was 0.940; the corresponding figure for genetic distance was 0.063. F-statistics analysis showed a total inbreeding coefficient (Fit) of 0.855 and high levels of genetic subdivision (Fst = 0.596) as well as of inbreeding within populations (Fis = 0.640). However, there was only a moderate level of genetic differentiation (Fst = 0.181) between the insular group of populations and the continental group.
A new concept of relatedness and its significance to the theory of social evolution
Authors: Drummond M.S.
Published: April 2005

Data on primitively social groups of Hymenoptera have been somewhat contradictory with respect to kin recognition, degree of relatedness and social evolution. This study presents a new concept of "relatedness coefficient". Called "aggregated relatedness", the hypothesis here introduced proposes that genes shared by any two individuals affect formation of family units to an extent dependent on their frequency and manner of dispersion in neighboring populations.
A program for representing and simulating population genetic phenomena
Authors: Nuin Paulo A.S. , Otto P.A.
Published: April 2005

The paper describes a computer program for representing and simulating population genetic phenomena, such as the distribution of gene and genotype frequencies under different mating systems (panmixia, inbreeding and assortative mating systems) and under influence of evolution factors (mutation, selection, gene flow and genetic drift). The program was written in Visual Basic (Microsoft, Inc.) and is able to run in any IBM-PC compatible computer running Windows 3.1 or later versions.
Effects of double-stranded RNA on virulence of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) against the silverleaf whitefly, Bemisia tabaci strain B (Homoptera: Aleyrodidae)
Authors: Azevedo Andréia Cristiane Souza , Sosa-Gómez Daniel Ricardo , Faria Marcos Rodrigues , Fungaro Maria Helena Pelegrinelli
Published: April 2005

Bands of double-stranded RNA (dsRNA) were detected in three out of twelve isolates of Paecilomyces fumosoroseus. Identity of these bands was confirmed by RNAse, DNAse and S1 nuclease treatments. The cure of dsRNA for one isolate (P92) was successfully carried out for a single conidium subculture. Isogenic strains, with or without dsRNA, were submitted to virulence tests against the whitefly Bemisia tabaci strain B. In contrast to findings for some phytopathogenic fungi, these dsRNA fragments did not cause hypovirulence in P. fumosoroseus.
A simplified CsCL protocol for lambda DNA purification: no enzymatic treatment/one phenol extraction
Authors: Santelli Roberto V. , Navarro-Cattapan Luci Deise
Published: April 2005

A modification of the CsCl gradient centrifugation method for DNA phage purification is presented. It avoids the enzymatic steps as well the need for a preliminary phage titration, a tedious process proposed in the majority of the protocols in use. The quality of the DNA obtained makes it amenable for additional manipulations like digestions, ligations, labelling, subcloning, etc.
Heterochromatin variation in chromosomes of Anopheles (Nyssorhynchus) darlingi Root and A.(N.) nuneztovari Gabaldón (Diptera: Culicidae)
Authors: Rafael Míriam Silva , Tadei Wanderli Pedro
Published: April 2005

C-banding was used to study the variations in heterochromatic block markings in chromosomes of Anopheles darlingi and A. nuneztovari from Manaus, State of Amazonas, and Macapá, State of Amapá, Brazil. Both species had two differently shaped X chromosomes and a Y chromosome that was entirely heterochromatic. The X1 chromosome of A. darlingi had markings that extended 1/3 of the total length whereas in the X2 chromosome the markings were located around the centromeric region. The markings on autosomal chromosomes were concentrated in the centromeric region in both species, with a heterochromatic block in one arm of chromosome II of A. darlingi. A. nuneztovari had three heterochromatic blocks in chromosome X1 (longer) and two blocks in X2 (shorter). X2X2 females were not detected in either species. The X1 and X2 chromosomes of males were found in A. darlingi, whereas in A. nuneztovari only the X1 chromosome was detected. Only intraspecific variation was found in heterochromatic block markings in the sex chromosomes and autosomes in the two populations of both species at each location.
Evidence of hybridization between two species of Melipona bees
Authors: Nascimento Vania Alves , Matusita Syomara Hakiko , Kerr Warwick Estevam
Published: April 2005

This report describes a case of hybridization between two species of Meliponinae bees (Melipona scutellaris from the Diamantina plateau in the State of Bahia, and Melipona capixaba from around Domingos Martins, in the State of Espírito Santo, Brazil). To demonstrate hybridization, electrophoretic profiles of esterase activity from three colonies were studied. Ten adult workers of M. scutellaris, M. capixaba and the hybrid colony were collected and processed individually. The pattern of esterase activity was constant for each species but differed between them, whereas hybrid bees had a pattern derived from both species. The fact that two ecologically different species of stingless bees separated by more than 300 km could still cross when placed in the same area suggests that there has not been any pressure to develop reproductive isolation.
Africanized honey bees (Apis mellifera L.) are more efficient at removing worker brood artificially infested with the parasitic mite Varroa jacobsoni Oudemans than are Italian bees or Italian/Africanized hybrids
Authors: Guerra Jr. José Carlos Vieira , Gonçalves Lionel Segui , Jong David De
Published: April 2005

Africanized honey bees are more tolerant of infestations with the mite Varroa jacobsoni than are honey bees of European origin. The capacity of these bees to detect and react to brood infested with this mite could be one of the factors determining this tolerance. We tested colonies of Africanized bees headed by queens from swarms collected in Ribeirão Preto, São Paulo State. The Italian colonies had queens imported directly from the USA, or from the Brazilian Island of Fernando de Noronha, where varroa-infested Italian colonies have been maintained, untreated, since 1984. Recently sealed worker brood cells were artificially infested by opening the cell capping, inserting live adult female mites and resealing the cells. Control cells were treated in the same way, but without introducing mites. The ability of the Africanized honey bees to recognize and remove this artificially infested brood was compared with that of first generation Italian/Africanized hybrid bees, and with the two groups of "pure" Italian bees, in three separate experiments. Africanized colonies removed a mean of 51% of the infested brood, while Italian/Africanized hybrid colonies removed 25%. Africanized colonies also removed a significantly greater proportion of infested brood than did Italian colonies, headed by queens from the USA (59 vs. 31%, respectively). Similarly, when Africanized colonies were compared with colonies of Italian bees from Fernando de Noronha, the former were found to be significantly more efficient at removing infested brood (61 vs. 35%, respectively), even though the population of Italian bees on this island has been exposed to and survived varroa infestations (without treatment) for more than 12 years. Only the Africanized honey bees removed a significant proportion of varroa-infested brood, when the data was corrected for brood removal from control cells.
Analysis of the sex ratio in Bradysia matogrossensis (Diptera, Sciaridae)
Authors: Rocha Lincoln S. , Perondini André Luiz P.
Published: April 2005

In sciarid flies, the control of sex determination and of the progeny sex ratio is exercised by the parental females, and is based on differential X-chromosome elimination in the initial stages of embryogenesis. In some species, the females produce unisexual progenies (monogenic females) while in others, the progenies consist of males and females (digenic females). The sex ratio of bisexual progenies is variable, and departs considerably from 1:1. Bradysia matogrossensis shows both monogenic and digenic reproduction. In a recently established laboratory strain of this species, 15% of the females were digenic, 10% produced only females, 13% produced only males, and 62% produced progenies with one predominant sex (33% predominantly of female and 29% predominantly male progenies). These progeny sex ratios were maintained in successive generations. Females from female-skewed progenies yielded female- and male-producing daughters in a 1:1 ratio. In contrast, daughters of females from male-skewed progenies produce bisexual or male-skewed progenies. The X-chromosome of B. matogrossensis shows no inversion or other gross aberration. These results suggest that the control of the progeny sex ratio (or differential X-chromosome elimination) involves more than one locus or, at least, more than one pair of alleles. The data also suggest that, in sciarid flies, monogeny and digeny may share a common control mechanism.
Effect of stannous chloride combined with caffeine on fecundity of Drosophila prosaltans
Authors: Itoyama Mary Massumi , Bicudo Hermione Elly Melara de Campos
Published: April 2005

The present study analyzed the number of progeny of stannous chloride- and/or caffeine-treated Drosophila prosaltans. A significant decreasing effect was observed in every case when compared to the control, except for the smallest stannous chloride dose used. Combinations of both substances using two different stannous chloride doses did not differ significantly from each other but number of progeny decreased 15% with the higher concentration combination when compared with caffeine-treated flies. The present results and data in the literature indicate that the effects of continuous ingestion of stannous chloride should be studied.
Estimates of repeatability and heritability of productive and reproductive traits in a herd of Jersey cattle
Authors: Roman R.M. , Wilcox C.J. , Martin F.G.
Published: April 2005

Estimates of the repeatability and heritability of 19 measures of performance in Jersey cows were obtained using an animal model with a relationship matrix and a derivative-free restricted maximum likelihood algorithm. The data consisted of 935 records for 374 cows by 69 sires over the period 1969-1987. The estimates were similar to those obtained by ordinary least squares methods reported for the same data set and in other studies, but had smaller error variances. A likelihood ratio test showed agreement between these heritability estimates and those in the literature. The heritability estimates of milk, fat, protein, lactose-mineral, solids-not-fat, and total solids yields were about 0.25; for the corresponding percentages, and for the protein to fat and solids-not-fat to fat ratios, the estimates were 0.50. Heritability estimates were 0.10 or less for the time from parturition to first breeding and for three measures of somatic cell counts. These estimates of heritability in a dairy cattle population in a subtropical environment were not different from those of populations in temperate climates.