RESUMO
Heat stress is a major factor that negatively affects animal welfare and production systems. Livestock should adapt to tropical and subtropical areas and to meet this, composite breeds have been developed. This work aimed to evaluate gene expression profiles in the skin of Brangus cattle under heat stress using a case-control design, and to correlate this with skin histological characteristics. Two groups of bulls were set using rectal temperature as a criterion to define stress conditions: stressed (N = 5) and non-stressed (N = 5) groups. Skin transcriptomics was performed and correlations between breed composition, phenotypic and skin histological traits were evaluated. Results showed 4309 differentially expressed genes (P < 0.01), 2113 downregulated and 2196 upregulated. Enrichment and ontology analyses revealed 132 GO terms and 67 pathways (P < 0.01), including thermogenesis, glycolysis, gluconeogenesis, mitochondrial activity, antioxidant and immune response, and apoptosis. The identity of the terms and pathways indicated the diversity of mechanisms directed to relieve the animals' suffering, acting from simple passive mechanisms (conduction, convection and radiation) to more complex active ones (behavioural changes, evaporation, vasodilation and wheezing). Furthermore, significant differences between phenotypic and skin histological traits and correlations between pairs of traits suggested a direction towards heat dissipation processes. In this sense, number of vessels was positively correlated with number of sweat glands (P < 0.001) and both were positively correlated with zebuine genetic content (P < 0.05 and P < 0.01, respectively), gland size was positively correlated with epidermal thickness and negatively with hair length (P < 0.05), and epidermal thickness was negatively correlated with gland-epidermis distance (P < 0.0005). These results support the notion that response to heat stress is physiologically complex, producing significant changes in the expression of genes involved in several biological pathways, while the animal's ability to face it depends greatly on their skin features.
Assuntos
Resposta ao Choque Térmico , Pele , Transcriptoma , Animais , Bovinos/genética , Bovinos/fisiologia , Resposta ao Choque Térmico/genética , Masculino , Pele/metabolismo , Perfilação da Expressão Gênica , Transtornos de Estresse por Calor/veterinária , Transtornos de Estresse por Calor/genética , Transtornos de Estresse por Calor/metabolismoRESUMO
Exposing pigs to heat stress (HS) provokes higher death of intestinal cells, resulting in elevated endogenous intestinal losses (EIL) of amino acids (AA) and damage to intestinal epithelia. Arginine (Arg) is precursor for the synthesis of polyamines, which are involved in proliferation of intestinal cells and restoration of the intestinal epithelia. Thus the effect of adding L-Arg to diets for HS pigs on the EIL of AA was analyzed. Twelve pigs (23.1 ± 1.1 kg body weight) implanted with T-type cannulas at the end of ileum were individually housed and allowed 15-days for surgery recovery under thermoneutral (TN) conditions (22 ± 2 °C). Following, the pigs were randomly assigned to one of three treatments: TN pigs fed a semi-purified, corn starch-3% casein basal diet (TN-B); HS pigs with the basal diet (HS-B); HS pigs consuming the basal diet supplemented with 0.20% L-Arg (HS-Arg). The experiment consisted of two 9-day periods; each period included 7-days of adaptation to their respective diet, followed by a 2-day ileal digesta collection period. Digesta was collected during 12 consecutive hours each day. The pigs were fed twice a-day. Ambient temperature (AT) inside the TN and HS rooms ranged from 18.6 to 27.6 °C and from 29.5 to 40.7 °C, respectively. Body temperature followed a pattern similar to that of AT. The daily EIL of indispensable AA increased (P < 0.01) in the HS-B pigs compared to both the TN-B and the HS-Arg pigs, however, there was no EIL difference between the TN-B and the HS-Arg pigs (P > 0.05). Likewise, with the exception of serine, daily losses of endogenous dispensable AA in the HS-B pigs were higher (P < 0.01) in comparison with those of TN-B and HS-Arg pigs. In summary, HS exposure compared to TN conditions increases the loss of endogenous AA, but dietary supplementation with L-Arg helped to counteract the negative HS effect.
Assuntos
Aminoácidos , Transtornos de Estresse por Calor , Animais , Aminoácidos/metabolismo , Ração Animal/análise , Arginina/farmacologia , Suplementos Nutricionais , Transtornos de Estresse por Calor/prevenção & controle , Transtornos de Estresse por Calor/veterinária , Transtornos de Estresse por Calor/metabolismo , Resposta ao Choque Térmico , SuínosRESUMO
Interferon tau (IFNT) is the cytokine responsible for the maternal recognition of pregnancy in ruminants and plays a role modulating embryo-maternal communication in the oviduct inducing a local response from immune cells. We aimed to investigate IFNT production, reactive oxygen species, and oxidative stress under the influence of heat stress (HS) during different stages of bovine in vitro embryo production. HS was established when the temperature was gradually raised from 38.5°C to 40.5°C in laboratory incubator, sustained for 6 hr, and decreased back to 38.5°C. To address the HS effects on IFNT production, reactive oxygen species, and oxidative stress, ovaries from a slaughterhouse were used according to treatments: control group (38.5°C); oocytes matured under HS; oocytes fertilized under HS; zygotes cultured in the first day under HS; and cells submitted to HS at oocyte maturation, fertilization, and the first day of zygote culture. The HS negatively affected cleavage and blastocyst rates, in all HS groups. On Day 7, all HS-treated embryos showed decrease IFNT gene and protein expressions, whereas reactive oxygen species were increased in comparison to the control. In conclusion, the compromised early embryo development due to higher temperatures during in vitro oocyte maturation, fertilization, and/or zygote stage have diminished IFNT expression and increased reactive oxygen species in bovine.
Assuntos
Bovinos/embriologia , Desenvolvimento Embrionário/fisiologia , Resposta ao Choque Térmico/fisiologia , Oócitos/fisiologia , Estresse Oxidativo/fisiologia , Zigoto/fisiologia , Animais , Células Cultivadas , Embrião de Mamíferos , Feminino , Fertilização in vitro/veterinária , Transtornos de Estresse por Calor/embriologia , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/fisiopatologia , Temperatura Alta , Técnicas de Maturação in Vitro de Oócitos , Interferon Tipo I/metabolismo , Oócitos/citologia , Oogênese/fisiologia , Proteínas da Gravidez/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Zigoto/citologiaRESUMO
The objective of this study was to determine whether the addition of açai (Euterpe oleracea) oil in the diets of lactating sheep under heat stress exerted beneficial effects on health as well as milk production and quality. Eighteen multiparous Lacaune sheep (2 or 3 parities; 28-30 days of lactation; average milk production of 1.7â¯L/sheep/day) were stratified by parity and milk production and were assigned randomly to 1 of 2 treatments (9 sheep/treatment): diet supplemented with 2% of soybean oil (SOY) or 2% of açai oil (AÇAI) in the concentrate for 14 days. The amount of oil added in the diet was equivalent to 0.65% of the total diet (dry matter basis). Blood and milk samples were collected on days 1, 10 and 14. On day 14, the AÇAI group sheep had lower serum concentrations of leukocytes, neutrophils, and lymphocytes than did the SOY group sheep. On day 14, AÇAI group sheep had lower serum concentration of triglycerides and urea, milk concentration of fat and total solid and milk lipid peroxidation than did SOY group sheep. However, on day 14, AÇAI group sheep had higher serum concentrations of glucose and globulin, serum and milk antioxidant capacity against peroxyl radicals, milk production and productive efficiency than did SOY group sheep. The fatty acids profile in milk did not differ between groups. These data suggest that açai oil improved the antioxidant activity in serum and milk and improved milk production and quality in dairy sheep under heat stress.
Assuntos
Suplementos Nutricionais , Euterpe , Transtornos de Estresse por Calor/metabolismo , Lactação/efeitos dos fármacos , Óleos de Plantas/farmacologia , Doenças dos Ovinos/metabolismo , Animais , Contagem de Células Sanguíneas , Dieta/veterinária , Ácidos Graxos/análise , Feminino , Transtornos de Estresse por Calor/sangue , Transtornos de Estresse por Calor/veterinária , Peroxidação de Lipídeos , Leite/química , Ovinos , Doenças dos Ovinos/sangueRESUMO
We aimed to evaluate the effects of acute heat stress (HS) and age on the redox state in broilers aged 21 and 42 days. We evaluated the expression of genes related to antioxidant capacity, the production of hydrogen peroxide (H2O2), and the activity of antioxidant enzymes in the liver, as well as oxidative stress markers in the liver and plasma. The experiment had a completely randomized factorial design with two thermal environments (thermoneutral and HS, 38°C for 24 h) and two ages (21 and 42 days). Twenty-one-day-old animals exposed to HS showed the highest thioredoxin reductase 1 (TrxR1) (P<0.0001) and glutathione synthetase (GSS) (P<0.0001) gene expression levels. Age influenced the expression of the thioredoxin (Trx) (P=0.0090), superoxide dismutase (SOD) (P=0.0194), glutathione reductase (GSR) (P<0.0001) and glutathione peroxidase 7 (GPx7) (P<0.0001) genes; we observed greater expression in birds at 21 days than at 42 days. Forty-two-day-old HS birds showed the highest H2O2 production (222.31 pmol dichlorofluorescein produced/min×mg mitochondrial protein). We also verified the effects of age and environment on the liver content of Glutathione (GSH) (P<0.0001 and P=0.0039, respectively) and catalase (CAT) enzyme activity (P=0.0007 and P=0.0004, respectively). Higher GSH content and lower CAT activity were observed in animals from the thermoneutral environment compared with the HS environment and in animals at 21 days compared with 42 days. Broilers at 42 days of age had higher plasma creatinine content (0.05 v. 0.01 mg/dl) and higher aspartate aminotransferase activity (546.50 v. 230.67 U/l) than chickens at 21 days of age. Our results suggest that under HS conditions, in which there is higher H2O2 production, 21-day-old broilers have greater antioxidant capacity than 42-day-old animals.
Assuntos
Antioxidantes/metabolismo , Galinhas/fisiologia , Transtornos de Estresse por Calor/veterinária , Peróxido de Hidrogênio/metabolismo , Doenças das Aves Domésticas/metabolismo , Fatores Etários , Animais , Catalase/metabolismo , Galinhas/genética , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Transtornos de Estresse por Calor/metabolismo , Temperatura Alta , Fígado/enzimologia , Fígado/metabolismo , Masculino , Oxirredução , Estresse Oxidativo , Superóxido Dismutase/metabolismoRESUMO
The aim of the present study was to evaluate the effects of heat stress (HS) and methionine supplementation on the markers of stress and on the gene expression levels of uncoupling proteins (UCP), betaine-homocysteine methyltransferase (BHMT), cystathionine ß-synthase (CBS), glutathione synthetase (GSS) and glutathione peroxidase 7 (GPx7). Broilers from 1 to 21 d and from 22 to 42 d of age were divided into three treatment groups related to methionine supplementation: without methionine supplementation (MD); recommended level of methionine supplementation (DL1); excess methionine supplementation (DL2). The broilers were either kept at a comfortable thermal temperature or exposed to HS (38°C for 24 h). During the starter period, we observed the effects of the interaction between diet and environment on the gene expression levels of UCP, BHMT and GSS. Higher gene expression levels of UCP and BHMT were observed in broilers that were maintained at thermal comfort conditions and received the MD diet. HS broilers fed the DL1 and DL2 diets had the highest expression level of GSS. The expression levels of the CBS and GPx7 genes were influenced by both the environment and methionine supplementation. During the grower period, the gene expression levels of BHMT, CBS, GSS and GPx7 were affected by the diet × environment interaction. A higher expression level of BHMT was observed in broilers maintained at thermal comfort conditions and on the MD diet. HS induced higher expression levels of CBS, GSS and GPx7 in broilers that received the DL1 and DL2 diets. The present results suggest that under HS conditions, methionine supplementation could mitigate the effects of stress, since methionine contributed to the increased expression levels of genes related to antioxidant activity.
Assuntos
Doenças das Aves/prevenção & controle , Dieta/veterinária , Regulação da Expressão Gênica no Desenvolvimento , Transtornos de Estresse por Calor/veterinária , Metionina/uso terapêutico , Estresse Oxidativo , Músculos Peitorais/enzimologia , Animais , Animais Endogâmicos , Antioxidantes/administração & dosagem , Antioxidantes/uso terapêutico , Proteínas Aviárias/genética , Proteínas Aviárias/metabolismo , Betaína-Homocisteína S-Metiltransferase/genética , Betaína-Homocisteína S-Metiltransferase/metabolismo , Biomarcadores/sangue , Biomarcadores/metabolismo , Doenças das Aves/dietoterapia , Doenças das Aves/metabolismo , Doenças das Aves/patologia , Galinhas , Ingestão de Energia , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Glutationa Sintase/genética , Glutationa Sintase/metabolismo , Transtornos de Estresse por Calor/dietoterapia , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/prevenção & controle , Homocisteína/sangue , Canais Iônicos/genética , Canais Iônicos/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Metionina/administração & dosagem , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Músculos Peitorais/metabolismo , Músculos Peitorais/patologia , Proteína Desacopladora 1 , Aumento de PesoRESUMO
Heat stress (HS) is a global problem which jeopardizes animal welfare, profitability, and global food security. Indirect effects of HS such as reduced feed intake contribute to, but do not fully explain, decreased productivity. Heat stressed animals initiate metabolic changes that do not reflect their plane of nutrition. This indicates that HS directly effects metabolism and productivity independent of reduced feed intake. In a variety of species, environmental hyperthermia compromises the intestinal barrier function resulting in increased permeability to luminal content including bacteria and bacterial components. Presumably, heat stress causes leaky gut in ruminants as well. The leakage of luminal content into the portal and ultimately the systemic circulation elicits an inflammatory response that may facilitate the detrimental effects of HS on animal agriculture. Identifying flexible management strategies (i.e. nutritional supplementation) to immediately decrease HS susceptibility without negatively influencing production traits would be of great value to global animal agriculture. Infertility and subfertility in production animals represent important economic, health and welfare issues. Non-successful breeding and embryonic mortality are major limitations to reproductive efficiency. Additionally, with increased requirements for efficient production of animal protein to feed a growing world economy, compromised fertility represents a global food security concern. This proceedings paper will focus chiefly on ruminant and swine reproduction for which the majority of knowledge has been acquired. The primary objective of this paper is to review an environmental stress (hyperthermia) and a physiological condition (bacterial infection) that both impair fecundity and fertility in domestic animal species. The secondary objective is to provide a brief summary of potential mitigation strategies to improve animal reproductive efficiency in the face of such stressors.
O estresse térmico (HS) é um problema global que põe em risco o bem estar animal, rentabilidade e segurança alimentar global. Efeitos indiretos de HS como redução de ingestão alimentar contribuem para a queda em produtividade, sem, portanto, explicar por completo. Animais com estresse térmico iniciam mudanças metabólicas que não refletem seu plano de nutrição. Isso indica que HS afeta diretamente o metabolismo e produtividade independente da ingestão reduzida de alimentos. Em diversas espécies a hipertermia ambiental compromete a função da barreira intestinal resultando em uma permeabilidade aumentada ao conteúdo do lúmen, incluindo bactéria e componentes bacterianos. O estresse térmico presumidamente também causa vazamento no intestino de ruminantes. O vazamento de conteúdo do lúmen no portal e finalmente na circulação sistêmica gera uma resposta inflamatória que pode facilitar os efeitos prejudiciais do HS na agricultura animal. A identificação de estratégias de gerenciamento flexíveis (i.e. suplementação nutricional) para imediatamente diminuir a susceptibilidade ao HS sem influenciar de forma negativa os traços de produção seria de grande valor para a agricultura animal global.Infertilidade e subfertilidade em animais de produção representam questões econômicas, de saúde e bem estar importantes. A reprodução sem sucesso e mortalidade de embriões são grandes limitações para a eficiência reprodutiva. Adicionalmente, com requisitos crescentes para a produção eficiente de proteína animal para alimentar uma crescente economia mundial, a fertilidade comprometida representa uma preocupação global de segurança alimentar. Este estudo de procedimentos focará principalmente na reprodução de ruminantes e suínos para os quais a maior parte do conhecimento foi adquirido.
Assuntos
Animais , Transtornos de Estresse por Calor/diagnóstico , Transtornos de Estresse por Calor/imunologia , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/veterinária , InsulinaRESUMO
Heat stress (HS) is a global problem which jeopardizes animal welfare, profitability, and global food security. Indirect effects of HS such as reduced feed intake contribute to, but do not fully explain, decreased productivity. Heat stressed animals initiate metabolic changes that do not reflect their plane of nutrition. This indicates that HS directly effects metabolism and productivity independent of reduced feed intake. In a variety of species, environmental hyperthermia compromises the intestinal barrier function resulting in increased permeability to luminal content including bacteria and bacterial components. Presumably, heat stress causes leaky gut in ruminants as well. The leakage of luminal content into the portal and ultimately the systemic circulation elicits an inflammatory response that may facilitate the detrimental effects of HS on animal agriculture. Identifying flexible management strategies (i.e. nutritional supplementation) to immediately decrease HS susceptibility without negatively influencing production traits would be of great value to global animal agriculture. Infertility and subfertility in production animals represent important economic, health and welfare issues. Non-successful breeding and embryonic mortality are major limitations to reproductive efficiency. Additionally, with increased requirements for efficient production of animal protein to feed a growing world economy, compromised fertility represents a global food security concern. This proceedings paper will focus chiefly on ruminant and swine reproduction for which the majority of knowledge has been acquired. The primary objective of this paper is to review an environmental stress (hyperthermia) and a physiological condition (bacterial infection) that both impair fecundity and fertility in domestic animal species. The secondary objective is to provide a brief summary of potential mitigation strategies to improve animal reproductive efficiency in the face of such stressors.(AU)
O estresse térmico (HS) é um problema global que põe em risco o bem estar animal, rentabilidade e segurança alimentar global. Efeitos indiretos de HS como redução de ingestão alimentar contribuem para a queda em produtividade, sem, portanto, explicar por completo. Animais com estresse térmico iniciam mudanças metabólicas que não refletem seu plano de nutrição. Isso indica que HS afeta diretamente o metabolismo e produtividade independente da ingestão reduzida de alimentos. Em diversas espécies a hipertermia ambiental compromete a função da barreira intestinal resultando em uma permeabilidade aumentada ao conteúdo do lúmen, incluindo bactéria e componentes bacterianos. O estresse térmico presumidamente também causa vazamento no intestino de ruminantes. O vazamento de conteúdo do lúmen no portal e finalmente na circulação sistêmica gera uma resposta inflamatória que pode facilitar os efeitos prejudiciais do HS na agricultura animal. A identificação de estratégias de gerenciamento flexíveis (i.e. suplementação nutricional) para imediatamente diminuir a susceptibilidade ao HS sem influenciar de forma negativa os traços de produção seria de grande valor para a agricultura animal global.Infertilidade e subfertilidade em animais de produção representam questões econômicas, de saúde e bem estar importantes. A reprodução sem sucesso e mortalidade de embriões são grandes limitações para a eficiência reprodutiva. Adicionalmente, com requisitos crescentes para a produção eficiente de proteína animal para alimentar uma crescente economia mundial, a fertilidade comprometida representa uma preocupação global de segurança alimentar. Este estudo de procedimentos focará principalmente na reprodução de ruminantes e suínos para os quais a maior parte do conhecimento foi adquirido.(AU)
Assuntos
Animais , Transtornos de Estresse por Calor/diagnóstico , Transtornos de Estresse por Calor/imunologia , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/veterinária , InsulinaRESUMO
Several physiological and metabolic changes are triggered in broilers submitted to high environmental temperatures, resulting in performance losses. Feed formulation manipulation of the dietary electrolyte balance may be applied to reduce the negative impact of heat stress on broiler performance. This experiment was carried out to evaluate the effect of the manipulations of dietary electrolytes by combining changes in the electrolyte (Na++K+-Cl-) balance (EB) and in the [(K++Cl-)/Na+] ratio (ER) in broiler feeds. In total, 1575 male broilers between 21 and 46 days old were allotted to 15 treatments in a 5x3 factorial arrangement, consisting of five diets with different EB/ER combinations (150/3, 250/2, 250/3, 250/4, and 350/3). Birds were submitted to heat stress at 25 or 35 days old. Live performance, mortality rate, and carcass traits were evaluated. The strategic formulation of diets with different EB and ER improves live performance and minimize the effect of heat stress on broilers. Under thermoneutral conditions, an EB of 250 mEq/kg and an ER of 3 are recommended, whereas under heat stress, and EB of 350 mEq/kg and an ER of 3 should be applied.(AU)
Assuntos
Animais , Galinhas/anormalidades , Galinhas/fisiologia , Transtornos de Estresse por Calor/diagnóstico , Transtornos de Estresse por Calor/veterinária , Transtornos de Estresse por Calor/metabolismoRESUMO
Several physiological and metabolic changes are triggered in broilers submitted to high environmental temperatures, resulting in performance losses. Feed formulation manipulation of the dietary electrolyte balance may be applied to reduce the negative impact of heat stress on broiler performance. This experiment was carried out to evaluate the effect of the manipulations of dietary electrolytes by combining changes in the electrolyte (Na++K+-Cl-) balance (EB) and in the [(K++Cl-)/Na+] ratio (ER) in broiler feeds. In total, 1575 male broilers between 21 and 46 days old were allotted to 15 treatments in a 5x3 factorial arrangement, consisting of five diets with different EB/ER combinations (150/3, 250/2, 250/3, 250/4, and 350/3). Birds were submitted to heat stress at 25 or 35 days old. Live performance, mortality rate, and carcass traits were evaluated. The strategic formulation of diets with different EB and ER improves live performance and minimize the effect of heat stress on broilers. Under thermoneutral conditions, an EB of 250 mEq/kg and an ER of 3 are recommended, whereas under heat stress, and EB of 350 mEq/kg and an ER of 3 should be applied.
Assuntos
Animais , Galinhas/anormalidades , Galinhas/fisiologia , Transtornos de Estresse por Calor/diagnóstico , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/veterináriaRESUMO
The aim of the present study was to identify the correlation between expression of heat shock protein 47 (Hsp47) and stress injury in heat-stressed myocardial cells and to compare variations in Hsp47 expression in rat myocardial cells exposed to different heat stress for varying periods in vitro and in vivo. Exposure to heat stress at 42°C resulted in similar induction patterns of the heart damage-related enzyme aspartate aminotransferase in the supernatants of H9c2 cells and in the serum of rats. Histological analysis revealed that both H9c2 cells and heart tissues displayed cellular degeneration in response to different periods of heat stress. Hsp47 was constitutively expressed in the cytoplasm of H9c2 cells at all time points during heat stress, which was consistent with observations in heart fibers in vivo. Immunoblotting analysis revealed no significant difference between the expression of Hsp47 in H9c2 cells and heart tissue. However, the expression of hsp47 mRNA in response to heat stress was significantly increased in H9c2 cells at 60 min (P < 0.01) and 100 min (P < 0.01), which was comparable to that at 100 min (P < 0.01) in the rat heart. Thus, Hsp47 was elevated significantly after hyperthermia at the mRNA level but not at the protein level both in vitro and in vivo. The results suggest that Hsp47 turnover may increase during heat stress or that Hsp47 consumption exceeds its production.
Assuntos
Proteínas de Choque Térmico HSP47/metabolismo , Resposta ao Choque Térmico/genética , Miócitos Cardíacos/metabolismo , Animais , Enzimas/sangue , Enzimas/metabolismo , Feminino , Proteínas de Choque Térmico HSP47/sangue , Proteínas de Choque Térmico HSP47/genética , Transtornos de Estresse por Calor/genética , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/patologia , Masculino , Miócitos Cardíacos/patologia , Ratos Sprague-DawleyRESUMO
Low temperature stress affects plant growth, including primary and secondary metabolism. Glyphosateresistant soybean contains a modified DNA, which encodes a different type of secondary metabolism enzyme related to lignin synthesis compared to conventional glyphosate-susceptible cultivars. Thus, this soybean cultivar might respond differently to low temperatures, compared to glyphosate-susceptible cultivars. This work aimed to investigate how decreasing temperatures influence the growth and lignin content of the glyphosate-resistant soybean compared to its susceptible parental cultivars. Three-day-old seedlings were cultivated in nutrient solution at 10, 15, 20, and 25°C (±2°C), using a 12-h photoperiod. After 96 h, taproot growth, fresh and dry biomass, and lignin levels were determined. The results indicate that lower temperatures decreased seedling and root growth in both types of cultivars; however, glyphosate-resistant soybean exhibited greater root length, biomass, and lignin content compared to the glyphosate-susceptible parental cultivar.(AU)
O estresse causado pela baixa temperatura, dentre outras implicações, afeta o crescimento do vegetal assim como o seu metabolismo secundário. Pelo fato da soja RR apresentar variante enzimática de uma das principais vias do metabolismo secundário, ligada à síntese de lignina, pode apresentar comportamento diferenciado, sob baixa temperatura, se comparada com sua linhagem parental. O objetivo deste trabalho foi investigar possíveis diferenças no crescimento e nos conteúdos de lignina nas raízes de soja cultivar transgênica resistente ao glifosato e cultivar parental em resposta a redução de temperatura. Após três dias de germinação das sementes, as plântulas foram mantidas em solução nutritiva, a 10, 15, 20 e 25°C (±2°C), com fotoperíodo de 12 horas. Após 96 horas, foi avaliado o comprimento relativo da raiz primária, biomassa fresca e seca das raízes e os teores de lignina. Os resultados mostram que a baixa temperatura promoveu redução no crescimento das plântulas e raízes. Dentre as cultivares em estudo, a soja transgênica apresentou maior comprimento relativo, biomassas e teores de lignina.(AU)
Assuntos
Transtornos de Estresse por Calor/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular , Temperatura , Glycine max/classificaçãoRESUMO
Low temperature stress affects plant growth, including primary and secondary metabolism. Glyphosateresistant soybean contains a modified DNA, which encodes a different type of secondary metabolism enzyme related to lignin synthesis compared to conventional glyphosate-susceptible cultivars. Thus, this soybean cultivar might respond differently to low temperatures, compared to glyphosate-susceptible cultivars. This work aimed to investigate how decreasing temperatures influence the growth and lignin content of the glyphosate-resistant soybean compared to its susceptible parental cultivars. Three-day-old seedlings were cultivated in nutrient solution at 10, 15, 20, and 25°C (±2°C), using a 12-h photoperiod. After 96 h, taproot growth, fresh and dry biomass, and lignin levels were determined. The results indicate that lower temperatures decreased seedling and root growth in both types of cultivars; however, glyphosate-resistant soybean exhibited greater root length, biomass, and lignin content compared to the glyphosate-susceptible parental cultivar.
O estresse causado pela baixa temperatura, dentre outras implicações, afeta o crescimento do vegetal assim como o seu metabolismo secundário. Pelo fato da soja RR apresentar variante enzimática de uma das principais vias do metabolismo secundário, ligada à síntese de lignina, pode apresentar comportamento diferenciado, sob baixa temperatura, se comparada com sua linhagem parental. O objetivo deste trabalho foi investigar possíveis diferenças no crescimento e nos conteúdos de lignina nas raízes de soja cultivar transgênica resistente ao glifosato e cultivar parental em resposta a redução de temperatura. Após três dias de germinação das sementes, as plântulas foram mantidas em solução nutritiva, a 10, 15, 20 e 25°C (±2°C), com fotoperíodo de 12 horas. Após 96 horas, foi avaliado o comprimento relativo da raiz primária, biomassa fresca e seca das raízes e os teores de lignina. Os resultados mostram que a baixa temperatura promoveu redução no crescimento das plântulas e raízes. Dentre as cultivares em estudo, a soja transgênica apresentou maior comprimento relativo, biomassas e teores de lignina.
Assuntos
Peptídeos e Proteínas de Sinalização Intercelular , Temperatura , Transtornos de Estresse por Calor/metabolismo , Glycine max/classificaçãoRESUMO
To compensate for stress imposed by salinity, biofilm formation and exopolysaccharide production are significant strategies of salt tolerant bacteria to assist metabolism. We hypothesized that two previously isolated salt-tolerant strains Halomonas variabilis (HT1) and Planococcus rifietoensis (RT4) have an ability to improve plant growth, These strains can form biofilm and accumulate exopolysacharides at increasing salt stress. These results showed that bacteria might be involved in developing microbial communities under salt stress and helpful in colonizing of bacterial strains to plant roots and soil particles. Eventually, it can add to the plant growth and soil structure. We investigated the comparative effect of exopolysacharide and biofilm formation in two bacterial strains Halomonas variabilis (HT1) and Planococcus rifietoensis (RT4) in response to varying salt stress. We found that biofilm formation and exopolysaccharide accumulation increased at higher salinity. To check the effect of bacterial inoculation on the plant (Cicer arietinum Var. CM-98) growth and soil aggregation, pot experiment was conducted by growing seedlings under salt stress. Inoculation of both strains increased plant growth at elevated salt stress. Weight of soil aggregates attached with roots and present in soil were added at higher salt concentrations compared to untreated controls. Soil aggregation was higher at plant roots under salinity. These results suggest the feasibility of using above strains in improving plant growth and soil fertility under salinity.
Assuntos
Biofilmes , Halomonas/metabolismo , Plâncton/metabolismo , Polissacarídeos Bacterianos/metabolismo , Solos Salitrosos/análise , Transtornos de Estresse por Calor/metabolismo , Métodos , Plantas , Microbiologia do SoloRESUMO
Several stimuli, including stress conditions, promote the activation of MAP kinases family members (ERK1/2, JNK, p38). In turn, these enzymes regulate several cellular functions. Given that MAPK activation requires the phosphorylation of these proteins, their inactivation depends on the activity of specific phosphatases. MAPK phosphatase-1 (MKP-1), a phosphatase specifically involved in the inactivation of MAPK family members, is induced by mitogenic stimuli and stress conditions. Here we describe the effect of heat shock (HS), 10 min, 45 degrees C, on MAPKs activities and MKP-1 mRNA and protein levels in Y1 adrenocortical cells. Western blot analysis performed with antibodies against the phosphorylated forms of ERK1/2 and JNK revealed that HS produced the rapid activation of these kinases. Their inactivation was also a rapid event and occurred together with the increase of MKP-1 protein levels detected by Western blot analysis. In addition, the effect of HS on MKP-1 protein levels seems to be exerted at the transcriptional level, since the amount of its mRNA in heat shocked cells was higher than in nonheated cells. Comparison of the temporal profiles of MKP-1 protein induction and MAPKs phospho-dephosphorylation suggests that MKP-1 induction could contribute to ERK1/2 and JNK inactivation after HS.