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BACKGROUND: Low temperatures are adverse contributors to cardiovascular diseases, but the associations between short-term exposure to cold and the risk of death from aortic dissection and aneurysm remain unclear, particularly in tropical regions. OBJECTIVE: This study was conducted based on 123,951 records of deaths caused by aortic dissection and aneurysms extracted from the national Mortality Information System in Brazil between 2000 and 2019. METHODS: Relative risks and 95 % confidence intervals (CI) for the aortic-related deaths associated with low ambient temperatures were estimated using the conditional logistic model combined with the distributed lag nonlinear model. Subgroup analyses were performed by age group, sex, race, education level, and residential region. Furthermore, this study calculated the number and fraction of aortic-related deaths attributed to temperatures below the temperature threshold to quantify the cold-related mortality burden of aortic diseases. RESULTS: During the study period, aortic-related deaths and mortality rates in Brazil exhibited a steady increase, rising from 4419 (2.66/100,000) in 2000 to 8152 (3.88/100,000) in 2019. Under the identified temperature threshold (26 °C), per 1 °C decrease in daily mean temperature was associated with a 4.77 % (95 % CI: 4.35, 5.19) increase in mortality risk of aortic-related diseases over lag 0-3 days. Females, individuals aged 50 years or older, Asian and Black race, and northern residents were more susceptible to low temperatures. Low temperatures were responsible for 19.10 % (95 % CI: 17.71, 20.45) of aortic-related deaths in Brazil. CONCLUSION: This study highlights that low temperatures were associated with an increased risk of aortic-related deaths, with a remarkable burden even in this predominantly tropical country.

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In Rio Grande do Sul, the main rice producer State in Brazil, low temperatures can occur during germination and seedling establishment, and in some cases, during the reproductive stage. When low temperatures occur in the early developmental stages cause delay in germination, resulting in a non-homogeneous growing. In reproductive stage, low temperatures cause spikelet sterility, directly interfering with plant yield. Researchers have shown that some phenolic compounds such as proanthocyanidins and anthocyanin are associated with low temperature tolerance in plants due to their antioxidant capacity. The red and black color in the seeds of some rice genotypes is conferred by the phenolic compounds proanthocyanidins and anthocyanin, respectively. Therefore, tis study aimed to verify whether rice genotypes with red or black seeds are more tolerant to low temperatures during germination. In this study, five rice genotypes were tested, two present seeds without pigmentation and with contrasting response to low temperature tolerance (BRS Bojuru - tolerant and BRS Pampeira - sensitive), two genotypes with red seeds (BRS 902, SCS 119 Rubi) and one black seed genotype (SCS 120 Ônix). As expected, the genotypes with pigmented seeds had a greater total phenolic compounds content. However, under low temperature conditions, the genotypes with pigmented seed showed a similar response to the sensitive genotype. Therefore, the presence of proanthocyanidins and anthocyanin in the seed of the studied genotypes does not provide tolerance to low temperatures during germination.(AU)

No Rio Grande do Sul, principal estado produtor de arroz do Brasil, baixas temperaturas podem ocorrer durante a germinação e estabelecimento de plântulas, e em alguns casos, durante o estádio reprodutivo. Quando baixas temperaturas ocorrem no estádio inicial de desenvolvimento causam atraso da germinação, resultando em um crescimento não homogêneo. No estádio reprodutivo, baixas temperaturas podem ocasionar esterilidade das espiguetas, interferindo diretamente na produtividade da planta. Pesquisas têm mostrado que alguns compostos fenólicos como as proantocianidinas e antocianinas estão associadas com tolerância a baixa temperatura em plantas devido sua capacidade antioxidante. A coloração vermelha e preta nas sementes de alguns genótipos de arroz é conferida pelos compostos fenólicos proantocianidinas e antocianinas, respectivamente. Portanto, o objetivo desse estudo foi verificar se os genótipos de arroz com sementes vermelhas ou pretas são mais tolerantes a baixas temperaturas durante a germinação. Neste trabalho, cinco genótipos foram testados, dois com sementes sem pigmentação e com resposta contrastante para tolerância a baixa temperatura (BRS Bojuru - tolerante e BRS Pampeira - sensível), dois genótipos com sementes vermelhas (BRS 902, SCS 119 Rubi) e um genótipo com sementes pretas (SCS 120 Ônix). Como esperado, os genótipos com sementes pigmentadas têm maior conteúdo de compostos fenólicos totais. Entretanto, sob condições de baixa temperatura, os genótipos com semente pigmentada mostraram resposta similar ao genótipo sensível. Dessa forma, a presença de proantocianidinas e antocianinas nas sementes dos genótipos estudados não confere tolerância a baixas temperaturas durante a germinação.(AU)

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BACKGROUND: Cold temperatures can aggravate pulmonary diseases and promote pulmonary arterial hypertension (PAH); however, the underlying mechanism has not been fully explored. AIM: To explore the effect of chronic cold exposure on the production of inflammatory cytokines and microRNAs (miRNAs) in a monocrotaline (MCT)-induced PAH model. METHODS: Male Sprague Dawley rats were divided into a Control (23.5 ± 2 °C), Cold (5.0 ± 1 °C for ten days), MCT (60 mg/kg body weight i.p.), and MCT + Cold (ten days of cold exposure after 3 weeks of MCT injection). Hemodynamic parameters, right ventricle (RV) hypertrophy, and pulmonary arterial medial wall thickness were determined. IL-1ß, IL-6, and TNF-α levels were determined using western blotting. miR-21-5p and -3p, miR-146a-5p and -3p, and miR-155-5p and -3p and plasma extracellular vesicles (EVs) and mRNA expression of Cd68, Cd163, Bmpr2, Smad5, Tgfbr2, and Smad3 were determined using RT-qPCR. RESULTS: The MCT + Cold group had aggravated RV hypertrophy hemodynamic parameters, and pulmonary arterial medial wall thickness. In lungs of the MCT + Cold, group the protein levels of TNF-α, IL-1ß, and IL-6 were higher than those in the MCT group. The mRNA expression of Cd68 and Cd163 were higher in the MCT + Cold group. miR-146a-5p and miR-155-5p levels were higher in the plasma EVs and lungs of the MCT + Cold group. Cold exposure promoted a greater decrease in miR-21-5p, Bmpr2, Smad5, Tgfbr2, and Smad3 mRNA expression in lungs of the MCT + Cold group. CONCLUSION: Cold exposure aggravates MCT-induced PAH with an increase in inflammatory marker and miRNA levels in the plasma EVs and lungs.

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AIM: An adverse endogenous environment during early life predisposes to metabolic disorder development. We previously reported adverse metabolic and adipose tissue effects in adult male rats born to dams fed with a fructose-rich diet (FRD). The aim of this work was to determine the effect of a FRD consumed by the pregnant mother on the white adipose tissue (WAT) browning capacity of male offspring at adulthood. MAIN METHODS: Adult SD male offspring from control (C) and FRD-fed mothers were exposed during one week to a cold stimulus. WAT browning capacity was studied through in vivo and in vitro approaches. KEY FINDINGS: After cold exposure, WAT browning was higher in fructose-programmed animals as evidenced by an increase in ucp-1 gene expression, protein levels, and higher UCP-1 positive foci. Moreover, pgc1-α gene expression was increased. In vitro studies showed a lower adipogenic capacity in cells of prenatally fructose-exposed animals differentiated with a white differentiation cocktail, while a higher ucp-1 expression was noted when their cells were treated with a pro-beige differentiation cocktail. SIGNIFICANCE: For the first time we demonstrate that pre-natal fructose exposure predisposes programmed male rats to a higher WAT browning-induced response, under stimulated conditions, despite an apparent lower basal thermogenic capacity. These results should be considered in future studies to generate new therapeutic approaches to deal with adverse programming malnutrition effects.

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Fiddler crabs live in an intertidal habitat and face several environmental constraints. Extreme environmental conditions, especially temperature affects their growth and reproduction. They use several strategies to deal with extreme temperatures. Among these, constructing burrows is important. Burrows act as a refuge during very high or low temperatures. This study investigates the temporal variations in air temperature, burrow temperature of large-sized male and female Austruca perplexa crabs, and the soil temperature near their burrows in Nakhon Si Thammarat province, southern Thailand (tropical climate). Air, burrow and soil temperatures were measured every 30 min in a day using temperature sensors. We observed that from 8:00 up to and including 17:30, burrow temperature was lower than soil temperature, but other times, burrow temperature was higher than soil temperature. In the case of air temperature, it was lower than soil or burrow temperatures most of the time in a day. When we compared temperatures among air, soil, and burrows at day (6:00 up to 17:30) and night (18:00 up to 5:30), burrow temperature was lower than soil temperature during the day but was higher at night. The air temperature was lower than soil or burrow temperatures on both day and night. This study shows that A. perplexa crab burrows can modulate the inside temperature and maintain a suitable temperature for the crabs.

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Fiddler crabs live in an intertidal habitat and face several environmental constraints. Extreme environmental conditions, especially temperature affects their growth and reproduction. They use several strategies to deal with extreme temperatures. Among these, constructing burrows is important. Burrows act as a refuge during very high or low temperatures. This study investigates the temporal variations in air temperature, burrow temperature of large-sized male and female Austruca perplexa crabs, and the soil temperature near their burrows in Nakhon Si Thammarat province, southern Thailand (tropical climate). Air, burrow and soil temperatures were measured every 30 min in a day using temperature sensors. We observed that from 8:00 up to and including 17:30, burrow temperature was lower than soil temperature, but other times, burrow temperature was higher than soil temperature. In the case of air temperature, it was lower than soil or burrow temperatures most of the time in a day. When we compared temperatures among air, soil, and burrows at day (6:00 up to 17:30) and night (18:00 up to 5:30), burrow temperature was lower than soil temperature during the day but was higher at night. The air temperature was lower than soil or burrow temperatures on both day and night. This study shows that A. perplexa crab burrows can modulate the inside temperature and maintain a suitable temperature for the crabs.(AU)

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AIMS: Investigate the role of melatonin on the regulation of body temperature in aged animals that have impaired melatonin production. MATERIAL AND METHODS: Aged Male Wistar rats were randomly assigned to the following groups: 1) control (vehicle added to the water bottles during the dark phase) and 2) melatonin-treated (10 mg/kg melatonin added to the water bottles during the dark phase). Before and after 16 weeks of vehicle or melatonin treatment, control group and melatonin-treated animals were acutely exposed to 18 °C for 2 h for an acute cold challenge and thermal images were obtained using an infrared camera. After 16 weeks, animals were euthanized and brown and beige adipocytes were collected for analysis of genes involved in the thermogenesis process by real-time PCR, and the uncoupling protein expression was evaluated by immunoblotting. Browning intensity of beige adipocytes were quantified by staining with hematoxylin-eosin. KEY FINDINGS: Chronic melatonin supplementation induced a minor increase in body mass and increased the animal's thermogenic potential in the cold acute challenge. Brown and beige adipocytes acted in a coordinated and complementary way to ensure adequate heat production. SIGNIFICANCE: Melatonin plays an important role in the thermoregulatory mechanisms, ensuring greater capacity to withstand cold and, also, participating in the regulation of energy balance.

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This study quantified the chilling requirements for the induction and overcoming of endodormancy (chilling-controlled physiological dormancy) of grapevines buds. Cuttings of the cultivars Chardonnay, Merlot and Cabernet Sauvignon were collected in vineyards in Veranópolis-RS in the winter period of 2019 and 2020. The cuttings were kept at a constant temperature of 7.2 °C or daily cycles of 7.2/18 °C for 6/18 h, 12/12 h or 18/6 h, up to 600 chilling hours (CH). Every 50 CH, part of the cuttings from each treatment was transferred to a temperature of 25 °C for daily assessment of the budburst in the green tip stage. The cultivars had different chilling requirements for inducing and overcoming endodormancy, reaching a total of 150 CH for ‘Chardonnay, 300 CH for ‘Merlot and 400 CH for ‘Cabernet Sauvignon. Of these, 50 CH were required to induce endodormancy in cultivars Chardonnay and Merlot and 100 CH for cultivar Cabernet Sauvignon. Dormancy evolution did not differ between cultivars in response to thermal regimes, with a temperature of 18 °C inert to the accumulation of CH. Precocity and uniformity of budburst were higher after chilling requirements were met during endodormancy for each genotype.(AU)

Este estudo visou quantificar as necessidades de frio para a indução e superação da endodormência (dormência fisiológica controlada por frio) de gemas de videiras. Estacas de das cultivares Chardonnay, Merlot e Cabernet Sauvignon foram coletadas em vinhedos em Veranópolis-RS, no período hibernal de 2019 e 2020. As estacas foram submetidas a temperatura de 7,2 ºC constante ou a ciclos diários de 7,2/18 °C por 6/18 h, 12/12 h ou 18/6 h, até 600 horas de frio (HF). A cada 50 HF, parte das estacas de cada tratamento foi transferida para a temperatura de 25°C, para avaliação diária da brotação das gemas, em estádio de ponta verde. As cultivares tiveram necessidades distintas de frio para indução e superação da endodormência, atingindo um total de 150 HF para ‘Chardonnay, 300 HF para ‘Merlot e 400 HF para ‘Cabernet Sauvignon. Destes totais, 50 HF foram necessárias para indução da endodormência nas cultivares Chardonnay e Merlot e 100 HF na cultivar Cabernet Sauvignon. A evolução da dormência não diferiu entre cultivares em resposta aos regimes térmicos, sendo a temperatura de 18 °C inerte ao acúmulo de HF. A precocidade e uniformidade de brotação das gemas foram maiores após suprido o frio na dormência para cada genótipo.(AU)

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This study quantified the chilling requirements for the induction and overcoming of endodormancy (chilling-controlled physiological dormancy) of grapevines buds. Cuttings of the cultivars Chardonnay, Merlot and Cabernet Sauvignon were collected in vineyards in Veranópolis-RS in the winter period of 2019 and 2020. The cuttings were kept at a constant temperature of 7.2 °C or daily cycles of 7.2/18 °C for 6/18 h, 12/12 h or 18/6 h, up to 600 chilling hours (CH). Every 50 CH, part of the cuttings from each treatment was transferred to a temperature of 25 °C for daily assessment of the budburst in the green tip stage. The cultivars had different chilling requirements for inducing and overcoming endodormancy, reaching a total of 150 CH for ‘Chardonnay’, 300 CH for ‘Merlot’ and 400 CH for ‘Cabernet Sauvignon’. Of these, 50 CH were required to induce endodormancy in cultivars Chardonnay and Merlot and 100 CH for cultivar Cabernet Sauvignon. Dormancy evolution did not differ between cultivars in response to thermal regimes, with a temperature of 18 °C inert to the accumulation of CH. Precocity and uniformity of budburst were higher after chilling requirements were met during endodormancy for each genotype.

Este estudo visou quantificar as necessidades de frio para a indução e superação da endodormência (dormência fisiológica controlada por frio) de gemas de videiras. Estacas de das cultivares Chardonnay, Merlot e Cabernet Sauvignon foram coletadas em vinhedos em Veranópolis-RS, no período hibernal de 2019 e 2020. As estacas foram submetidas a temperatura de 7,2 ºC constante ou a ciclos diários de 7,2/18 °C por 6/18 h, 12/12 h ou 18/6 h, até 600 horas de frio (HF). A cada 50 HF, parte das estacas de cada tratamento foi transferida para a temperatura de 25°C, para avaliação diária da brotação das gemas, em estádio de ponta verde. As cultivares tiveram necessidades distintas de frio para indução e superação da endodormência, atingindo um total de 150 HF para ‘Chardonnay’, 300 HF para ‘Merlot’ e 400 HF para ‘Cabernet Sauvignon’. Destes totais, 50 HF foram necessárias para indução da endodormência nas cultivares Chardonnay e Merlot e 100 HF na cultivar Cabernet Sauvignon. A evolução da dormência não diferiu entre cultivares em resposta aos regimes térmicos, sendo a temperatura de 18 °C inerte ao acúmulo de HF. A precocidade e uniformidade de brotação das gemas foram maiores após suprido o frio na dormência para cada genótipo.

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This paper reports the evaluation of digestibility, immunological parameters, and resistance to thermal shock at low temperature in Litopenaeus vannamei fed diets with diferent Aurantiochytrium sp. meal additions (0; 0.5; 1 and 2%). First, the apparent digestibility coefficient of the ingredient was determined. The digestibility of the microalgae meal was high for protein (74.90%); around 60% for lipids, and for docosahexaenoic fatty acid (DHA) it was 55.61%. After, shrimp rearing with the feed additive was carried out in a clear water system, containing 25 shrimp (initial weight: 4.89 ± 0.27g) per 400 L tank. Feeding occurred four times a day. After a three-week period, immunological parameters were evaluated and thermal shock was performed. Animals fed 0.5% and 2% of the microalgae Aurantiochytrium sp. showed higher survival to thermal shock. In immunological analyses, the serum agglutiniting titer was higher (p <0.05) in the 0.5 and 2% additions of the microalgae meal, and the phenoloxidase activity (PO) was higher in the 1% addition (p <0.05). It is concluded that there is good utilization of the nutrients of Aurantiochytrium sp. meal by L. vannamei and its addition to the diet (0.5 and 1%) increased shrimp resistance to thermal shock.

Avaliou-se a digestibilidade, os parâmetros imunológicos e a resistência ao choque térmico a baixa temperatura em Litopenaeus vannamei alimentado com dietas contendo diferentes proporções de farinha da microalga Aurantiochytrium sp. (0; 0,5; 1 e 2%). Inicialmente, foi determinado o coeficiente de digestibilidade aparente do ingrediente. A digestibilidade da farinha da microalga foi alta para proteína (74,9%), e em torno no 60% para lipídeos em geral, sendo que para o ácido graxo docosahexaenóico (DHA) foi de 55,61%. Posteriormente, o cultivo com o aditivo alimentar foi realizado em sistema de água clara, contendo 25 camarões (peso inicial 4,89 ± 0,27 g) por tanque de 400 L, alimentados quatro vezes ao dia. Após o período de três semanas, foram avaliados os parâmetros imunológicos e realizado o choque térmico. Os animais alimentados com 0,5% e 1% da microalga na dieta apresentaram melhor sobrevivência ao choque térmico. Nas análises imunológicas, o título aglutinante do soro foi significativamente superior (p <0,05) nas adições de 0,5 e 2% da farinha da microalga, e a atividade da fonoloxidade (PO) na adição de 1% (p <0,05). Conclui-se que a farinha de Aurantiochytrium sp. tem bom aproveitamento de seus nutrientes por L. vannamei e sua adição na dieta (0,5 e 1%) aumentou a resistência dos camarões à variação térmica.

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