RESUMO
Sheep and goat production takes place under unsuitable climate conditions, where animals are more susceptible to high temperatures. The objectives of this study were to determine, i) whether sexual behavior of photo-stimulated bucks varies through 24 h/day in March and April and, ii) whether the environmental temperature and the relative humidity affect their expression. Six bucks were submitted to artificial long days (16 h light and 8 h darkness per day/2.5 months). Bucks were exposed to ovariectomized females once a week during the non-breeding period and sexual behavior was recorded for 15 min at 2 h intervals along 24 h/day. The environmental temperature, relative humidity, temperature-humidity index (THI), and body temperature were recorded in each behavior test. Plasma testosterone, sexual behavior, environmental temperature, relative humidity, and body temperature were analyzed using Generalized Estimation Equations. Plasma testosterone showed a significant difference over the experimental period (P < 0.001). The highest frequency of nudging and anogenital sniffing was at 08:00 h (P < 0.001); flehmen and penis unsheathed were variable (P < 0.001). The highest environmental temperature and the lowest relative humidity were registered from 14:00 to 18:00 h (P < 0.001). The highest body temperature was at 18:00 h and the lowest was at 06:00 h (P < 0.001). The highest THI >77 was recorded at 16:00 h. In conclusion, photo-stimulated bucks showed a variation of sexual behavior through 24 h/day exposed to ovariectomized females, and these sexual activities were affected by the high environmental temperature and the low relative humidity throughout the study.(AU)
Assuntos
Animais , Masculino , Ruminantes/metabolismo , Comportamento Sexual Animal/efeitos da radiação , Aclimatação/efeitos da radiaçãoRESUMO
Sheep and goat production takes place under unsuitable climate conditions, where animals are more susceptible to high temperatures. The objectives of this study were to determine, i) whether sexual behavior of photo-stimulated bucks varies through 24 h/day in March and April and, ii) whether the environmental temperature and the relative humidity affect their expression. Six bucks were submitted to artificial long days (16 h light and 8 h darkness per day/2.5 months). Bucks were exposed to ovariectomized females once a week during the non-breeding period and sexual behavior was recorded for 15 min at 2 h intervals along 24 h/day. The environmental temperature, relative humidity, temperature-humidity index (THI), and body temperature were recorded in each behavior test. Plasma testosterone, sexual behavior, environmental temperature, relative humidity, and body temperature were analyzed using Generalized Estimation Equations. Plasma testosterone showed a significant difference over the experimental period (P 77 was recorded at 16:00 h. In conclusion, photo-stimulated bucks showed a variation of sexual behavior through 24 h/day exposed to ovariectomized females, and these sexual activities were affected by the high environmental temperature and the low relative humidity throughout the study.
Assuntos
Masculino , Animais , Aclimatação/efeitos da radiação , Comportamento Sexual Animal/efeitos da radiação , Ruminantes/metabolismoRESUMO
Sheep and goat production takes place under unsuitable climate conditions, where animals are more susceptible to high temperatures. The objectives of this study were to determine, i) whether sexual behavior of photo-stimulated bucks varies through 24 h/day in March and April and, ii) whether the environmental temperature and the relative humidity affect their expression. Six bucks were submitted to artificial long days (16 h light and 8 h darkness per day/2.5 months). Bucks were exposed to ovariectomized females once a week during the non-breeding period and sexual behavior was recorded for 15 min at 2 h intervals along 24 h/day. The environmental temperature, relative humidity, temperature-humidity index (THI), and body temperature were recorded in each behavior test. Plasma testosterone, sexual behavior, environmental temperature, relative humidity, and body temperature were analyzed using Generalized Estimation Equations. Plasma testosterone showed a significant difference over the experimental period (P < 0.001). The highest frequency of nudging and anogenital sniffing was at 08:00 h (P < 0.001); flehmen and penis unsheathed were variable (P < 0.001). The highest environmental temperature and the lowest relative humidity were registered from 14:00 to 18:00 h (P < 0.001). The highest body temperature was at 18:00 h and the lowest was at 06:00 h (P < 0.001). The highest THI >77 was recorded at 16:00 h. In conclusion, photo-stimulated bucks showed a variation of sexual behavior through 24 h/day exposed to ovariectomized females, and these sexual activities were affected by the high environmental temperature and the low relative humidity throughout the study.(AU)
Assuntos
Animais , Masculino , Ruminantes/metabolismo , Comportamento Sexual Animal/efeitos da radiação , Aclimatação/efeitos da radiaçãoRESUMO
This study evaluated the occupational exposure of workers to heat during manual harvesting of coffee. The case study was conducted between May to August. Occupational heat in coffee plantations was evaluated using the Wet Bulb Globe Temperature (WBGT) method and the metabolic rate. The WBGT was obtained using the TGD 400 thermal stress meter. The determined WBGT values were compared to two standards: the Occupational Hygiene Standard (NHO) 06 and Regulatory Norm (NR) 09. For acclimatized workers, the exposure limit was not exceeded at any time during the evaluated period. Fornon-acclimatized workers, the exposure limit was not exceeded only in July.
O presente trabalhado teve como objetivo avaliar a exposição ocupacional de trabalhadores ao calor durante a colheita manual do cafeeiro. O estudo de caso foi desenvolvido entre os meses de maio a agosto. Avaliou-se o calor ocupacional em lavoura cafeeira através do método do Índice Bulbo Úmido Termômetro de Globo (IBUTG) e taxa metabólica. O IBUTG foi obtido utilizando o medidor de estresse térmico TGD 400. Os valores do IBUTG determinados foram comparados com duas normativas: Norma de Higiene Ocupacional (NHO) 06 e Norma Regulamentadora (NR) 09. Para trabalhadores aclimatizados o limite de exposição não foi superado em nenhum momento do período avaliado. Em relação aos trabalhadores não aclimatizados o limite de exposição não foi superado apenas em julho.
Assuntos
Humanos , Aclimatação/efeitos da radiação , Adaptação Fisiológica/efeitos da radiação , CaféRESUMO
This study evaluated the occupational exposure of workers to heat during manual harvesting of coffee. The case study was conducted between May to August. Occupational heat in coffee plantations was evaluated using the Wet Bulb Globe Temperature (WBGT) method and the metabolic rate. The WBGT was obtained using the TGD 400 thermal stress meter. The determined WBGT values were compared to two standards: the Occupational Hygiene Standard (NHO) 06 and Regulatory Norm (NR) 09. For acclimatized workers, the exposure limit was not exceeded at any time during the evaluated period. Fornon-acclimatized workers, the exposure limit was not exceeded only in July.(AU)
O presente trabalhado teve como objetivo avaliar a exposição ocupacional de trabalhadores ao calor durante a colheita manual do cafeeiro. O estudo de caso foi desenvolvido entre os meses de maio a agosto. Avaliou-se o calor ocupacional em lavoura cafeeira através do método do Índice Bulbo Úmido Termômetro de Globo (IBUTG) e taxa metabólica. O IBUTG foi obtido utilizando o medidor de estresse térmico TGD 400. Os valores do IBUTG determinados foram comparados com duas normativas: Norma de Higiene Ocupacional (NHO) 06 e Norma Regulamentadora (NR) 09. Para trabalhadores aclimatizados o limite de exposição não foi superado em nenhum momento do período avaliado. Em relação aos trabalhadores não aclimatizados o limite de exposição não foi superado apenas em julho.(AU)
Assuntos
Humanos , Aclimatação/efeitos da radiação , Adaptação Fisiológica/efeitos da radiação , CaféRESUMO
The aim of this study was to evaluate the efficiency of the load wetting method to attenuate the ambience of the load the transport of broilers. Fourteen commercial consignments were monitored over a 25 km route, and in seven of these, the load wetting was carried (LW) out while in the other seven no wetting was done (LD). The temperatures of the side, top and rear load boxes were analyzed by infrared thermography. The central row load boxes were evaluated by geostatistics, using temperature variability (TA), relative humidity (RH) and the enthalpy comfort index (ECI). The mean was compared by Student's t-test (P < 0.05). The results showed that load wetting has a momentary effect (P < 0.05). The boxes located in the central rows in the LW showed a higher (P < 0.05) ECI compared to those in the LD. Inaddition, areas classified as lethal were formed in the LW. In conclusion, load wetting was not an efficient method to attenuate the ambience of load during the commercial transport of broilers, as it only has momentary and transient effects.(AU)
Assuntos
Animais , Galinhas , Produtos Avícolas/economia , Aclimatação/efeitos da radiaçãoRESUMO
The aim of this study was to evaluate the efficiency of the load wetting method to attenuate the ambience of the load the transport of broilers. Fourteen commercial consignments were monitored over a 25 km route, and in seven of these, the load wetting was carried (LW) out while in the other seven no wetting was done (LD). The temperatures of the side, top and rear load boxes were analyzed by infrared thermography. The central row load boxes were evaluated by geostatistics, using temperature variability (TA), relative humidity (RH) and the enthalpy comfort index (ECI). The mean was compared by Student's t-test (P < 0.05). The results showed that load wetting has a momentary effect (P < 0.05). The boxes located in the central rows in the LW showed a higher (P < 0.05) ECI compared to those in the LD. Inaddition, areas classified as lethal were formed in the LW. In conclusion, load wetting was not an efficient method to attenuate the ambience of load during the commercial transport of broilers, as it only has momentary and transient effects.
Assuntos
Animais , Aclimatação/efeitos da radiação , Galinhas , Produtos Avícolas/economiaRESUMO
Flavodoxins are electron carrier flavoproteins present in bacteria and photosynthetic microorganisms which duplicate the functional properties of iron-sulphur containing ferredoxins and replace them under adverse environmental situations that lead to ferredoxin decline. When expressed in plant chloroplasts, flavodoxin complemented ferredoxin deficiency and improved tolerance to multiple sources of biotic, abiotic and xenobiotic stress. Analysis of flavodoxin-expressing plants grown under normal conditions, in which the two carriers are present, revealed phenotypic effects unrelated to ferredoxin replacement. Flavodoxin thus provided a tool to alter the chloroplast redox poise in a customized way and to investigate its consequences on plant physiology and development. We describe herein the effects exerted by the flavoprotein on the function of the photosynthetic machinery. Pigment analysis revealed significant increases in chlorophyll a, carotenoids and chlorophyll a/b ratio in flavodoxin-expressing tobacco lines. Results suggest smaller antenna size in these plants, supported by lower relative contents of light-harvesting complex proteins. Chlorophyll a fluorescence and P700 spectroscopy measurements indicated that transgenic plants displayed higher quantum yields for both photosystems, a more oxidized plastoquinone pool under steady-state conditions and faster plastoquinone dark oxidation after a pulse of saturating light. Many of these effects resemble the phenotypes exhibited by leaves adapted to high irradiation, a most common environmental hardship faced by plants growing in the field. The results suggest that flavodoxin-expressing plants would be better prepared to cope with this adverse situation, and concur with earlier observations reporting that hundreds of stress-responsive genes were induced in the absence of stress in these lines.
Assuntos
Aclimatação/efeitos da radiação , Flavodoxina/genética , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Nicotiana/metabolismo , Fotossíntese/efeitos da radiação , Folhas de Planta/genética , Relação Dose-Resposta à Radiação , Fenótipo , Folhas de Planta/efeitos da radiação , Nicotiana/genética , Nicotiana/fisiologia , Nicotiana/efeitos da radiaçãoRESUMO
Polymeric nanoparticles have emerged as carrier systems for molecules that release nitric oxide (NO), a free radical involved in plant stress responses. However, to date, nanoencapsulated NO donors have not been applied to plants under realistic field conditions. Here, we verified the effects of free and nanoencapsulated NO donor, S-nitroso-mercaptosuccinic acid (S-nitroso-MSA), on growth, physiological and biochemical parameters of neotropical tree seedlings kept under full sunlight in the nursery for acclimation. S-nitroso-MSA incorporation into chitosan nanoparticles partially protected the NO donor from thermal and photochemical degradation. The application of nanoencapsulated S-nitroso-MSA in the substrate favoured the growth of seedlings of Heliocarpus popayanensis, a shade-intolerant tree. In contrast, free S-nitroso-MSA or nanoparticles containing non-nitrosated mercaptosuccinic acid reduced photosynthesis and seedling growth. Seedlings of Cariniana estrellensis, a shade-tolerant tree, did not have their photosynthesis and growth affected by any formulations, despite the increase of foliar S-nitrosothiol levels mainly induced by S-nitroso-MSA-loaded nanoparticles. These results suggest that depending on the tree species, nanoencapsulated NO donors can be used to improve seedling acclimation in the nursery.
Assuntos
Aclimatação , Nanopartículas/metabolismo , Doadores de Óxido Nítrico/administração & dosagem , Doadores de Óxido Nítrico/farmacocinética , Óxido Nítrico/farmacocinética , Plântula/metabolismo , Luz Solar , Aclimatação/efeitos dos fármacos , Aclimatação/fisiologia , Aclimatação/efeitos da radiação , Portadores de Fármacos , Composição de Medicamentos , Liberação Controlada de Fármacos , Jardins , Nanopartículas/química , Doadores de Óxido Nítrico/farmacologia , Fotossíntese/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , S-Nitrosotióis/administração & dosagem , S-Nitrosotióis/química , S-Nitrosotióis/farmacocinética , S-Nitrosotióis/farmacologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Tiomalatos/administração & dosagem , Tiomalatos/farmacocinética , Tiomalatos/farmacologia , Árvores/efeitos dos fármacos , Árvores/metabolismo , Árvores/efeitos da radiação , Clima TropicalRESUMO
Gevuina avellana (Proteaceae) is a typical tree from the South American temperate rainforest. Although this species mostly regenerates in shaded understories, it exhibits an exceptional ecological breadth, being able to live under a wide range of light conditions. Here we studied the genetic basis that underlies physiological acclimation of the photosynthetic responses of G. avellana under contrasting light conditions. We analyzed carbon assimilation and light energy used for photochemical processes in plants acclimated to contrasting light conditions. Also, we used a transcriptional profile of leaf primordia from G. avellana saplings growing under different light environments in their natural habitat, to identify the gene coexpression network underpinning photosynthetic performance and light-related processes. The photosynthetic parameters revealed optimal performance regardless of light conditions. Strikingly, the mechanism involved in dissipation of excess light energy showed no significant differences between high- and low-light-acclimated plants. The gene coexpression network defined a community structure consistent with the photochemical responses, including genes involved mainly in assembly and functioning of photosystems, photoprotection, and retrograde signaling. This ecophysiological genomics approach improves our understanding of the intraspecific variability that allows G. avellana to have optimal photochemical and photoprotective mechanisms in the diverse light habitats it encounters in nature.