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Ladivania Medeiros do Nascimento Everardo Valadares de Sá Barretto Sampaio Maria Jesus Nogueira Rodal Ana Carolina Borges Lins-e-Silva 《Journal of Forest Research》2014,19(6):501-513
Changes in physiognomy, species composition and structure, and dispersal mechanisms of canopy and subcanopy plant assemblages were investigated along a chronosequence of three ages: 12, 20, and 50+ years old (=old-growth), three replications in each, in an Atlantic Forest landscape in Northeastern Brazil. Our objective was to investigate whether there is floristic and structural convergence along secondary succession. There were significant differences between secondary and old-growth forests in density and basal area only for the subcanopy. Differences in density between forest ages were noted when the assemblage was analyzed per diameter and height classes. Richness of canopy species of both secondary ages differed from those of old-growth forests. Some dominant species in the canopy of secondary forests showed a significant decrease in density with increasing age, which indicates an ongoing process of floristic changes. The low level of shared species between secondary and old-growth forests supports the idea that species composition is one of the last components to recover during successional process. Zoochory was the most important dispersal guild in species percentage and number, irrespective of stand age. Although regenerating areas can take alternative pathways, our results indicate that secondary Atlantic Forest sites have a high potential for natural regeneration. This recovery is recorded as a physiognomic convergence of the canopy layer in as little as 12 years, and progressive introductions of later successional species into the plant assemblage that lead to convergence in terms of the diversity and richness of the subcanopy and of dispersal guilds just 20 years after abandonment. 相似文献
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Paiva SR Facó O Faria DA Lacerda T Barretto GB Carneiro PL Lobo RN McManus C 《Tropical animal health and production》2011,43(7):1449-1457
The first registers of Somali sheep in Brazil are from the beginning of the 1900s. This breed, adapted to the dry climate
and scarce food supply, is restricted in the northeast region of the country. Molecular marker technologies, especially those
based on genotyping microsatellite and mtDNA loci, can be used in conjunction with breeding (pedigree analysis) and consequently
the maintenance of genetic variation in herds. Animals from the Brazilian Somali Conservation Nuclei from Embrapa Sheep and
Goats in Ceará State were used to validate genetic monitoring by traditional pedigree methods and molecular markers. Nineteen
microsatellite markers and 404 base pairs from the control region of mtDNA were used. For total herd diversity, an average
5.32 alleles were found, with expected heterozygosity of 0.5896, observed heterozygosity of 0.6451, 0.4126 for molecular coancestrality,
and coefficient of inbreeding (F
IS) was −0.095. Comparing molecular coancestrality means over the years, there was a consistent increase in this parameter within
the herd, increasing from 0.4157 to 0.4769 in 2 years (approx. 12% variation). Sixteen mtDNA haplotypes were identified. Inbreeding
and other estimates from genealogical analyses confirm the results from molecular markers. From these results, it is possible
to state that microsatellites are useful tools in genetic management of herds, especially when routine herd recording is not
carried out, or there were gaps in recent generations. As well as pedigree control, genetic diversity can be optimized. Based
on the results, and despite herd recording in the herd of Brazilian Somali of Embrapa Sheep and Goats, additional management
measures need to be carried out in this herd to reduce inbreeding and optimize genetic variation. 相似文献
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FS Gonçalves LSS Barretto RP Arruda SHV Perri GZ Mingoti 《Reproduction in domestic animals》2010,45(1):129-135
Increased amounts of reactive oxygen species (ROS) during in vitro fertilization (IVF) may cause cytotoxic damage to gametes, whereas small amounts of ROS favour sperm capacitation. The aim of this study was to investigate the effect of antioxidants [50 μ m β-mercaptoethanol (β-ME) and 50 μ m cysteamine (Cyst)] or a pro-oxidant (5 m m buthionine sulfoximine) on the quality and penetrability of spermatozoa into bovine oocytes and on the subsequent embryo development and quality when added during IVF. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes, and mitochondrial function, was diminished (p < 0.05) after 4-h culture in the presence of antioxidants. Oocyte penetration rates were similar between treatments (p > 0.05), but antioxidants adversely affected the normal pronuclear formation rates (p < 0.05). The incidence of polyspermy was high for β-ME (p < 0.05). No differences were observed in cleavage rates between treatments (p > 0.05). However, the developmental rate to the blastocyst stage was adversely affected by Cyst treatment (p < 0.05). The quality of embryos that reached the blastocyst stage, evaluated by total, inner cell mass (ICM) and trophectoderm cell numbers and ICM/total cell ratio was unaffected (p > 0.05) by treatments. The results indicate that ROS play a role in the fertilizing capacity in bovine spermatozoa, as well as in the interaction between the spermatozoa and the oocytes. It can be concluded that supplementation with antioxidants during IVF procedures impairs sperm quality, normal pronuclear formation and embryo development to the blastocyst stage. 相似文献
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J. M. M. Henck C. V. Bis-Souza M. A. R. Pollonio A. C. S. Barretto 《British poultry science》2019,60(6):716-723
ABSTRACT1. The current consumer preference for healthier meat products is associated with less additives in manufacturing (so-called ‘clean-label’) or the addition of non-meat ingredients with functional properties, recognised as improving specific technological properties in meat products.2. This study evaluated the effect of the addition of alpha-cyclodextrin and wheat fibre to low-fat chicken frankfurters containing 35% mechanically deboned chicken meat on the technological and sensorial properties during refrigerated storage.3. The results showed that the addition of dietary fibres (alpha-cyclodextrin and wheat fibre) in low-fat chicken frankfurters improved emulsion stability, hardness, chewiness and reduced cohesiveness.4. Alpha-cyclodextrin helped the retention of fat globules in the microstructure and affected colour in the sensorial evaluation.5. The use of alpha-cyclodextrin, in combination with wheat fibre, as a new ingredient to substitute fat in emulsified meat products containing mechanically deboned chicken, improved emulsion stability and texture.6. Alpha-cyclodextrin and wheat fibre were effective in contributing to fat reduction without affecting the sensory properties of the product. 相似文献
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