839 resultados para Selective Breeding
Resumo:
Nulliparous female Syrian hamsters were used to investigate the effect of two different breeding systems on the fertility of the female Syrian hamster. We hypothesized that females submitted to a harem system (HS) would deliver smaller and more female-biased litters than in a monogamic system. Ten female and 10 adult male hamsters housed individually (G1) were kept in a monogamic temporary breeding system, while 10 females and five males (G2) were submitted to HS with two females and a male permanently housed together since female weaning. Females from G1 and G2 delivered, respectively, 47 and 50 litters, and produced 364 (G1) and 383 (G2) weaned pups without any difference in litter size, mean weight of weaned pups and body condition of dams. Interparturition intervals were shorter and the percentage of male pups per litter was higher in the HS possibly as a result of different endocrine conditions provided by different breeding systems. Besides providing evidence that housing conditions can influence the sex of hamster offspring, our findings suggest a mechanism for the non-random distribution of male and female pups in hamster litters.
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The aim of this study was to evaluate micronucleus (MN) frequency in polychromatic erythrocytes (PCE) of female rats in persistent estrus (a model developed to mimic polycystic ovary syndrome) treated with selective estrogen receptor modulators (SERMs, tamoxifen, and raloxifene). Forty female Wistar-Hannover rats were divided into four groups of 10 animals each: Group I (normally cycling rats) and Group II (persistent estrus) both received only vehicle, while Group III (persistent estrus) was treated with tamoxifen (250 mu g/animal/day) and Group IV (persistent estrus) was treated with raloxifene (750 mu g/animal/day). Tamoxifen and raloxifene were given by oral gavage beginning on postnatal day 90 and continuing for 30 consecutive days. Peripheral blood samples were collected from tails 1 day following the last exposure. Blood smears were made on glass slides and stained with 10% Giemsa solution. ANOVA and a Tukey post-hoc test were used for data analysis. Mean percentages of MN were 1.82 +/- 0.13, 5.20 +/- 0.24, 3.32 +/- 0.13, and 3.04 +/- 0.12 in Groups I, II, III, and IV, respectively. The results indicate that tamoxifen and raloxifene similarly reduced the formation of MNPCE of female rats in persistent estrus (P < 0.0001 for Groups III and IV vs. Group II), using the dosages and time periods applied in the present study. The data suggest possibly antimutagenic effects of SERMs under high levels of estrogens. The findings also suggest that this is an interesting animal model for studying the genotoxicity of estrogens. Environ. Mol. Mutagen. 2012. (C) 2011 Wiley Periodicals, Inc.
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Skeletal tissues of 49 humpback whales Megaptera novaeangliae that stranded between 2002 and 2011 along the Abrolhos Bank seashore and its adjacent waters in Brazil were studied. Twelve (24.5%) animals presented pathological changes in one or more bones. Degenerative changes and developmental malformations were most frequent (10.2% each), followed by inflammatory/infectious and traumatic lesions (8.2% each). Infectious diseases led to severe lesions of the caudal vertebrae of 2 whales. In one of these individuals, the lesions involved 6 caudal vertebrae, leading to ankylosis of 3 vertebrae. Degenerative changes were observed in the vertebral columns of 3 animals, involving the joints of 13 ribs of 1 individual, and in the humerus of 1 whale. Traumatic lesions, such as osseous callus in the ribs, were observed in 4 animals. In 1 whale, the rib showed severe osteomyelitis, possibly resulting from the infection of multiple fractures. Developmental abnormalities such as spina bifida on 3 cervical vertebrae of 1 whale, fusion of spinal processes on thoracic vertebrae of 1 individual and fusion of the first 2 ribs unilaterally or bilaterally in 4 animals were found. Chronic infectious conditions found in the axial skeleton may have restrained spinal mobility and had detrimental effects on the general health of the animals, contributing to stranding and death. To our knowledge, this is the first systematic study on skeletal lesions in stranded humpback whales.
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Background/Purpose: The mechanisms of increased collagen production and liver parenchyma fibrosis are poorly understood. These phenomena are observed mainly in children with biliary obstruction (BO), and in a great number of patients, the evolution to biliary cirrhosis and hepatic failure leads to the need for liver transplantation before adolescence. However, pediatric liver transplantation presents with biliary complications in 20% to 30% of cases in the postoperative period. Intra-or extrahepatic stenosis of bile ducts is frequent and may lead to secondary biliary cirrhosis and the need for retransplantation. It is unknown whether biliary stenosis involving isolated segments or lobes may affect the adjacent nonobstructed lobes by paracrine or endocrine means, leading to fibrosis in this parenchyma. Therefore, the present study aimed to create an experimental model of selective biliary duct ligation in young animals with a subsequent evaluation of the histologic and molecular alterations in liver parenchyma of the obstructed and nonobstructed lobes. Methods: After a pilot study to standardize the surgical procedures, weaning rats underwent ligation of the bile ducts of the median, left lateral, and caudate liver lobes. The bile duct of the right lateral lobe was kept intact. To avoid intrahepatic biliary duct collaterals neoformation, the parenchymal connection between the right lateral and median lobes was clamped. The animals were divided into groups according to the time of death: 1, 2, 3, 4, and 8 weeks after surgical procedure. After death, the median and left lateral lobes (with BO) and the right lateral lobe (without BO [NBO]) were harvested separately. A group of 8 healthy nonoperated on animals served as controls. Liver tissues were subjected to histologic evaluation and quantification of the ductular proliferation and of the portal fibrosis. The expressions of smooth muscle alpha-actin (alpha-SMA), desmin, and transforming growth factor beta 1 genes were studied by molecular analyses (semiquantitative reverse transcriptase-polymerase chain reaction and real-time polymerase chain reaction, a quantitative method). Results: Histologic analyses revealed the occurrence of ductular proliferation and collagen formation in the portal spaces of both BO and NBO lobes. These phenomena were observed later in NBO than BO. Bile duct density significantly increased 1 week after duct ligation; it decreased after 2 and 3 weeks and then increased again after 4 and 8 weeks in both BO and NBO lobes. The portal space collagen area increased after 2 weeks in both BO and NBO lobes. After 3 weeks, collagen deposition in BO was even higher, and in NBO, the collagen area started decreasing after 2 weeks. Molecular analyses revealed increased expression of the alpha-SMA gene in both BO and NBO lobes. The semiquantitative and quantitative methods showed concordant results. Conclusions: The ligation of a duct responsible for biliary drainage of the liver lobe promoted alterations in the parenchyma and in the adjacent nonobstructed parenchyma by paracrine and/or endocrine means. This was supported by histologic findings and increased expression of alpha-SMA, a protein related to hepatic fibrogenesis. (C) 2012 Elsevier Inc. All rights reserved.
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Much effort has been devoted to understanding the function of extrafloral nectaries (EFNs) for antplantherbivore interactions. However, the pattern of evolution of such structures throughout the history of plant lineages remains unexplored. In this study, we used empirical knowledge on plant defences mediated by ants as a theoretical framework to test specific hypotheses about the adaptive role of EFNs during plant evolution. Emphasis was given to different processes (neutral or adaptive) and factors (habitat change and trade-offs with new trichomes) that may have affected the evolution of antplant associations. We measured seven EFN quantitative traits in all 105 species included in a well-supported phylogeny of the tribe Bignonieae (Bignoniaceae) and collected field data on antEFN interactions in 32 species. We identified a positive association between ant visitation (a surrogate of ant guarding) and the abundance of EFNs in vegetative plant parts and rejected the hypothesis of phylogenetic conservatism of EFNs, with most traits presenting K-values < 1. Modelling the evolution of EFN traits using maximum likelihood approaches further suggested adaptive evolution, with static-optimum models showing a better fit than purely drift models. In addition, the abundance of EFNs was associated with habitat shifts (with a decrease in the abundance of EFNs from forest to savannas), and a potential trade-off was detected between the abundance of EFNs and estipitate glandular trichomes (i.e. trichomes with sticky secretion). These evolutionary associations suggest divergent selection between species as well as explains K-values < 1. Experimental studies with multiple lineages of forest and savanna taxa may improve our understanding of the role of nectaries in plants. Overall, our results suggest that the evolution of EFNs was likely associated with the adaptive process which probably played an important role in the diversification of this plant group.
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A data set of a commercial Nellore beef cattle selection program was used to compare breeding models that assumed or not markers effects to estimate the breeding values, when a reduced number of animals have phenotypic, genotypic and pedigree information available. This herd complete data set was composed of 83,404 animals measured for weaning weight (WW), post-weaning gain (PWG), scrotal circumference (SC) and muscle score (MS), corresponding to 116,652 animals in the relationship matrix. Single trait analyses were performed by MTDFREML software to estimate fixed and random effects solutions using this complete data. The additive effects estimated were assumed as the reference breeding values for those animals. The individual observed phenotype of each trait was adjusted for fixed and random effects solutions, except for direct additive effects. The adjusted phenotype composed of the additive and residual parts of observed phenotype was used as dependent variable for models' comparison. Among all measured animals of this herd, only 3160 animals were genotyped for 106 SNP markers. Three models were compared in terms of changes on animals' rank, global fit and predictive ability. Model 1 included only polygenic effects, model 2 included only markers effects and model 3 included both polygenic and markers effects. Bayesian inference via Markov chain Monte Carlo methods performed by TM software was used to analyze the data for model comparison. Two different priors were adopted for markers effects in models 2 and 3, the first prior assumed was a uniform distribution (U) and, as a second prior, was assumed that markers effects were distributed as normal (N). Higher rank correlation coefficients were observed for models 3_U and 3_N, indicating a greater similarity of these models animals' rank and the rank based on the reference breeding values. Model 3_N presented a better global fit, as demonstrated by its low DIC. The best models in terms of predictive ability were models 1 and 3_N. Differences due prior assumed to markers effects in models 2 and 3 could be attributed to the better ability of normal prior in handle with collinear effects. The models 2_U and 2_N presented the worst performance, indicating that this small set of markers should not be used to genetically evaluate animals with no data, since its predictive ability is restricted. In conclusion, model 3_N presented a slight superiority when a reduce number of animals have phenotypic, genotypic and pedigree information. It could be attributed to the variation retained by markers and polygenic effects assumed together and the normal prior assumed to markers effects, that deals better with the collinearity between markers. (C) 2012 Elsevier B.V. All rights reserved.
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The purpose of this article is to show how quantitative genetics has contributed to the huge genetic progress obtained in plant breeding in Brazil in the last forty years. The information obtained through quantitative genetics has given Brazilian breeders the possibility of responding to innumerable questions in their work in a much more informative way, such as the use or not of hybrid cultivars, which segregating population to use, which breeding method to employ, alternatives for improving the efficiency of selection programs, and how to handle the data of progeny and/or cultivars evaluations to identify the most stable ones and thus improve recommendations.
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This paper describes an outbreak of chytridiomycosis affecting a group of Dendrobates tinctorius, a Neotropical anuran species, confiscated from the illegal wildlife trade and housed in a private zoo in Brazil as part of an ex situ breeding program. We examined histological sections of the skin of 30 D. tinctorius and 20 Adelphobates galactonotus individuals. Twenty D. tinctorius (66.7%) and none of the A. galactonotus were positive for Batrachochytrium dendrobatidis (Bd). Multiple development stages of Bd infection were observed. The reasons for the interspecific difference in the rate of infection could not be determined, and further studies are advised. Because the examined population consisted of confiscated frogs, detailed epidemiological aspects could not be investigated, and the source of the fungus remains uncertain. The existence of ex situ amphibian populations is important for protecting species at higher risk in the wild, and ex situ amphibian conservation and breeding programs in Brazil may be established using confiscated frogs as founders. However, this paper alerts these programs to the urgency of strict quarantine procedures to prevent the introduction of potential pathogens, particularly Bd, into ex situ conservation programs.
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Clinical effectiveness of group cognitive-behavioral therapy (GCBT) versus fluoxetine in obsessive-compulsive disorder outpatients that could present additional psychiatric comorbidities was assessed. Patients (18-65 years; baseline Yale-Brown Obsessive-Compulsive-Scale [Y-BOCS] scores >= 16; potentially presenting additional psychiatric comorbidities) were sequentially allocated for treatment with GCBT (n = 70) or fluoxetine (n = 88). Mean Y-BOCS scores decreased by 23.13% in the GCBT and 21.54% in the SSRI groups (p = 0.875). Patients presented a mean of 2.7 psychiatric comorbidities. and 81.4% showed at least one additional disorder. A reduction of at least 35% in baseline Y-BOCS scores and CGI ratings of 1 (much better) or 2 (better) was achieved by 33.3% of GCBT patients and 27.7% in the SSRI group (p = 0.463). The Y-BOCS reduction was significantly lower in patients with one or more psychiatric comorbidities (21.15%, and 18.73%, respectively) than in those with pure OCD (34.62%; p = 0.034). Being male, having comorbidity of Major Depression, Social Phobia, or Dysthymia predicted a worse response to both treatments. Response rates to both treatments were similar and lower than reported in the literature, probably due to the broad inclusion criteria and the resulting sample more similar to the real world population. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
Myocardial remodeling and heart failure (HF) are common sequelae of many forms of cardiovascular disease and a leading cause of mortality worldwide. Accumulation of damaged cardiac proteins in heart failure has been described. However, how protein quality control (PQC) is regulated and its contribution to HF development are not known. Here, we describe a novel role for activated protein kinase C isoform beta II (PKC beta II) in disrupting PQC. We show that active PKC beta II directly phosphorylated the proteasome and inhibited proteasomal activity in vitro and in cultured neonatal cardiomyocytes. Importantly, inhibition of PKC beta II, using a selective PKC beta II peptide inhibitor (beta IIV5-3), improved proteasomal activity and conferred protection in cultured neonatal cardiomyocytes. We also show that sustained inhibition of PKC beta II increased proteasomal activity, decreased accumulation of damaged and misfolded proteins and increased animal survival in two rat models of HF. Interestingly, beta IIV5-3-mediated protection was blunted by sustained proteasomal inhibition in HF. Finally, increased cardiac PKC beta II activity and accumulation of misfolded proteins associated with decreased proteasomal function were found also in remodeled and failing human hearts, indicating a potential clinical relevance of our findings. Together, our data highlights PKC beta II as a novel inhibitor of proteasomal function. PQC disruption by increased PKC beta II activity in vivo appears to contribute to the pathophysiology of heart failure, suggesting that PKC beta II inhibition may benefit patients with heart failure. (218 words)
Resumo:
Thiazolidinediones (TZDs) act through peroxisome proliferator activated receptor (PPAR) gamma to increase insulin sensitivity in type 2 diabetes (T2DM), but deleterious effects of these ligands mean that selective modulators with improved clinical profiles are needed. We obtained a crystal structure of PPAR gamma ligand binding domain (LBD) and found that the ligand binding pocket (LBP) is occupied by bacterial medium chain fatty acids (MCFAs). We verified that MCFAs (C8-C10) bind the PPAR gamma LBD in vitro and showed that they are low-potency partial agonists that display assay-specific actions relative to TZDs; they act as very weak partial agonists in transfections with PPAR gamma LBD, stronger partial agonists with full length PPAR gamma and exhibit full blockade of PPAR gamma phosphorylation by cyclin-dependent kinase 5 (cdk5), linked to reversal of adipose tissue insulin resistance. MCFAs that bind PPAR gamma also antagonize TZD-dependent adipogenesis in vitro. X-ray structure B-factor analysis and molecular dynamics (MD) simulations suggest that MCFAs weakly stabilize C-terminal activation helix (H) 12 relative to TZDs and this effect is highly dependent on chain length. By contrast, MCFAs preferentially stabilize the H2-H3/beta-sheet region and the helix (H) 11-H12 loop relative to TZDs and we propose that MCFA assay-specific actions are linked to their unique binding mode and suggest that it may be possible to identify selective PPAR gamma modulators with useful clinical profiles among natural products.
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Surveys were conducted in Brazil, Benin and Tanzania to collect predatory mites as candidates for control of the coconut mite Aceria guerreronis Keifer, a serious pest of coconut fruits. At all locations surveyed, one of the most dominant predators on infested coconut fruits was identified as Neoseiulus baraki Athias-Henriot, based on morphological similarity with regard to taxonomically relevant characters. However, scrutiny of our own and published descriptions suggests that consistent morphological differences may exist between the Benin population and those from the other geographic origins. In this study, we combined three methods to assess whether these populations belong to one species or a few distinct, yet closely related species. First, multivariate analysis of 32 morphological characters showed that the Benin population differed from the other three populations. Second, DNA sequence analysis based on the mitochondrial cytochrome oxidase subunit I (COI) showed the same difference between these populations. Third, cross-breeding between populations was unsuccessful in all combinations. These data provide evidence for the existence of cryptic species. Subsequent morphological research showed that the Benin population can be distinguished from the others by a new character (not included in the multivariate analysis), viz. the number of teeth on the fixed digit of the female chelicera.
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The aim of this study was to assess selective plating methodologies for the enumeration and identification of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus, Lactobacillus rhamnosus and Bifidobacterium animalis ssp. lactis in fermented milks. Seven agar media (MRS with added sorbitol, clindamycin or vancomycin, acidified MRS, RCA with added aniline blue and dicloxacilin, M17 and ST) were evaluated. The results showed that RCA dicloxacilin agar was suitable for the selective enumeration of B. animalis ssp. lactis in fermented milk. Either MRS (acidified) or M17 agar could be used for enumeration of L. delbrueckii ssp. bulgaricus and S. thermophilus, respectively. MRS media containing antibiotics were effective for the enumeration of the probiotic organisms (L. rhamnosus and L. acidophilus) inoculated in fermented milks.
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The novel coumarin-based 'turn-on' fluorescent probe (E)-3-(2,5-dimethoxybenzylideneamino)-7-hydroxy-2H-chromen-2-one (MGM) was designed, synthesized, and characterized. This compound shows high selectivity for Cu+2, combined with a large fluorescence enhancement upon binding to Cu2+. Benesi-Hildebrand and Job plots demonstrate that the stoichiometry of the Cu+2 complex formed is 2:1. Preliminary studies employing epifluorescence microscopy demonstrated that Cu+2 could be imaged in human neuroblastoma SH-SY5Y cells treated with MGM. (c) 2012 Elsevier Ltd. All rights reserved.
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We studied the presence of primary resistance to raltegravir (RAL), natural polymorphisms, and selection pressure on HIV-1 integrase. We found a high frequency of integrase polymorphisms related to the resistance to RAL and sequence stability. Further studies are needed to determine the importance of these polymorphisms to RAL resistance.