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1.
Nat Commun ; 11(1): 551, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992708

RESUMO

The wings of Lepidoptera contain a matrix of living cells whose function requires appropriate temperatures. However, given their small thermal capacity, wings can overheat rapidly in the sun. Here we analyze butterfly wings across a wide range of simulated environmental conditions, and find that regions containing living cells are maintained at cooler temperatures. Diverse scale nanostructures and non-uniform cuticle thicknesses create a heterogeneous distribution of radiative cooling that selectively reduces the temperature of structures such as wing veins and androconial organs. These tissues are supplied by circulatory, neural and tracheal systems throughout the adult lifetime, indicating that the insect wing is a dynamic, living structure. Behavioral assays show that butterflies use wings to sense visible and infrared radiation, responding with specialized behaviors to prevent overheating of their wings. Our work highlights the physiological importance of wing temperature and how it is exquisitely regulated by structural and behavioral adaptations.


Assuntos
Adaptação Fisiológica/fisiologia , Comportamento Animal , Borboletas/fisiologia , Termotolerância/fisiologia , Asas de Animais/fisiologia , Animais , Metabolismo Energético/fisiologia , Hemolinfa/fisiologia , Raios Infravermelhos , Modelos Biológicos , Nanoestruturas , Energia Solar , Temperatura Ambiente , Termodinâmica , Sensação Térmica , Asas de Animais/anatomia & histologia , Asas de Animais/citologia , Asas de Animais/efeitos da radiação
2.
Biol Lett ; 16(1): 20190716, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31937216

RESUMO

Extreme heat events are becoming more common as a result of anthropogenic global change. Developmental plasticity in physiological thermal limits could help mitigate the consequences of thermal extremes, but data on the effects of early temperature exposure on thermal limits later in life are rare, especially for vertebrate ectotherms. We conducted an experiment that to our knowledge is the first to isolate the effect of egg (i.e. embryonic) thermal conditions on adult heat tolerance in a reptile. Eggs of the lizard Anolis sagrei were incubated under one of three fluctuating thermal regimes that mimicked natural nest environments and differed in mean and maximum temperatures. After emergence, all hatchlings were raised under common garden conditions until reproductive maturity, at which point heat tolerance was measured. Egg mortality was highest in the warmest treatment, and hatchlings from the warmest treatment tended to have greater mortality than those from the cooler treatments. Despite evidence that incubation temperatures were stressful, we found no evidence that incubation treatment influenced adult heat tolerance. Our results are consistent with a low capacity for organisms to increase their physiological heat tolerance via plasticity, and emphasize the importance of behavioural and evolutionary processes as mechanisms of resilience to extreme heat.


Assuntos
Lagartos , Termotolerância , Animais , Evolução Biológica , Meio Ambiente , Temperatura Alta , Temperatura Ambiente
3.
Insect Sci ; 27(1): 159-169, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29851277

RESUMO

Agasicles hygrophila has been introduced worldwide as a control agent for the invasive weed Alternanthera philoxeroides. However, global warming has potential impact on its controlling efficacy. The aim of this research was to explore the primary factors responsible for the greatly reduced A. hygrophila population in hot summers. To imitate the temperature conditions in summers, different developmental stages of A. hygrophila were treated with high temperatures from 32.5 °C to 45 °C for 1-5 h. Based on the survival rate, the heat tolerance of each developmental stage was ranked from lowest to highest as follows: egg, 1st, 2nd, 3rd instar larva, adult and pupa. Eggs showed the lowest heat tolerance with 37.5 °C as the critical temperature affecting larval hatching. Heat treatment of the A. hygrophila eggs at 37.5 °C for 1 h decreased the hatch rate to 24%. Our results indicated that when compared with the control at 25 °C, 1 h treatment at 37.5 °C prolonged the duration of the egg stage, shortened the duration of oviposition and total longevity, and changed the reproductive pattern of A. hygrophila. The net reproductive rate, intrinsic rate and finite rate were all significantly reduced. The results suggest that low heat tolerance of the eggs was the major factor responsible for the reduction of A. hygrophila populations, and the key temperature was 37.5 °C. Therefore, appropriate measures should be taken to protect eggs in order to maintain the efficacy of A. hygrophila in the biological control of A. philoxeroides in hot summers.


Assuntos
Besouros/fisiologia , Temperatura Alta/efeitos adversos , Termotolerância , Animais , Besouros/crescimento & desenvolvimento , Feminino , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Óvulo/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Estações do Ano
4.
Biosci Biotechnol Biochem ; 84(4): 832-841, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31851582

RESUMO

Thermotolerant strains are critical for low-cost high temperature fermentation. In this study, we carried out the thermal adaptation of A. pasteurianus IFO 3283-32 under acetic acid fermentation conditions using an experimental evolution approach from 37ºC to 40ºC. The adapted strain exhibited an increased growth and acetic acid fermentation ability at high temperatures, however, with the trade-off response of the opposite phenotype at low temperatures. Genome analysis followed by PCR sequencing showed that the most adapted strain had 11 mutations, a single 64-kb large deletion, and a single plasmid loss. Comparative phenotypic analysis showed that at least the large deletion (containing many ribosomal RNAs and tRNAs genes) and a mutation of DNA polymerase (one of the 11 mutations) critically contributed to this thermotolerance. The relationship between the phenotypic changes and the gene mutations are discussed, comparing with another thermally adapted A. pasteurianus strains obtained previously.


Assuntos
Acetobacter/fisiologia , Evolução Molecular , Genoma Bacteriano , Termotolerância , Ácido Acético/metabolismo , Acetobacter/genética , Acetobacter/metabolismo , Fermentação , Mutação
5.
J Appl Microbiol ; 128(1): 301-309, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31541508

RESUMO

AIMS: The aim of this study was to evaluate the microbiological quality of commercially prepared ready-to-eat (RTE) sushi by enumerating aerobic mesophilic bacteria (AMB) and thermotolerant coliforms (TC) and detecting Escherichia coli and Salmonella ssp. An isolate was identified as E. coli O157:H7 which was evaluated for its virulence and antimicrobial resistance profiling as well as its ability to form biofilms on stainless steel. METHODS AND RESULTS: There were four sampling events in seven establishments, totalling 28 pools of sushi samples. Mean AMB counts ranged between 5·2 and 7·7 log CFU per gram. The enumeration of TC varied between 2·1 and 2·7 log MPN per gram. Salmonella ssp. were not detected, and one sample was positive for E. coli and was identified as E. coli O157:H7. To the best of our knowledge, this is the first report of E. coli O157:H7 in sushi samples in the world literature. This isolate presented virulence genes stx1, stx2, eae and hlyA. It was also susceptible to 14 antimicrobials tested and had the ability to form biofilms on stainless steel. CONCLUSIONS: There is a need to improve the good hygiene practices adopted in establishments selling sushi in the city of Pelotas, Brazil. In addition, the isolated E. coli O157:H7 carries a range of important virulence genes being a potential risk to consumer health, as sushi is a RTE food. This isolate also presents biofilm formation ability, therefore, may trigger a constant source of contamination in the production line of this food. SIGNIFICANCE AND IMPACT OF THE STUDY: The increase in the consumption of sushi worldwide attracts attention regarding the microbiological point of view, since it is a ready-to-eat food. To our knowledge, this was the first time that E. coli O157:H7 was identified in sushi samples.


Assuntos
Escherichia coli O157/isolamento & purificação , Microbiologia de Alimentos , Alimentos Marinhos/microbiologia , Animais , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Brasil , Contagem de Colônia Microbiana , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/genética , Escherichia coli O157/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Aço Inoxidável , Termotolerância , Virulência/genética
6.
Phytomedicine ; 66: 153132, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31790899

RESUMO

BACKGROUND: Chlorogenic acid (CGA) is a polyphenol widely distributed in plants and plant-derived food with antioxidant and protective activities against cell stress. Caenorhabditis elegans is a model organism particularly useful for understanding the molecular and biochemical mechanisms associated with aging and stress in mammals. In C. elegans, CGA was shown to improve resistance to thermal, while the underlying mechanisms that lead to this effect require further understanding. PURPOSE: The present study was conducted to investigate the underlying molecular mechanisms behind CGA response conferring thermotolerance to C. elegans. METHODS AND RESULTS: Signaling pathways that could be involved in the CGA-induced thermotolerance were evaluated in C. elegans strains with loss-of-function mutation. CGA-induced thermotolerance required hypoxia-inducible factor HIF-1 but no insulin pathway. CGA exposition (1.4 µM CGA for 18 h) before thermal stress treatment increased HIF-1 levels and activity. HIF-1 activation could be partly attributed to an increase in radical oxygen species and a decrease in superoxide dismutase activity. In addition, CGA exposition before thermal stress also increased autophagy just as hormetic heat condition (HHC), worms incubated at 36 °C for 1 h. RNAi experiments evidenced that autophagy was increased by CGA via HIF-1, heat-shock transcription factor HSF-1 and heat-shock protein HSP-16 and HSP-70. In contrast, autophagy induced by HHC only required HSF-1 and HSP-70. Moreover, suppression of autophagy induction showed the significance of this process for adapting C. elegans to cope with thermal stress. CONCLUSION: This study demonstrates that CGA-induced thermotolerance in C. elegans is mediated by HIF-1 and downstream, by HSF-1, HSPs and autophagy resembling HHC.


Assuntos
Autofagia/efeitos dos fármacos , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/efeitos dos fármacos , Ácido Clorogênico/farmacologia , Proteínas de Choque Térmico/metabolismo , Fatores de Transcrição/metabolismo , Animais , Antioxidantes/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/genética , Ácido Clorogênico/química , Proteínas de Choque Térmico/genética , Resposta ao Choque Térmico , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Termotolerância/efeitos dos fármacos , Fatores de Transcrição/genética
7.
PLoS Negl Trop Dis ; 13(11): e0007464, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31738754

RESUMO

Tsetse flies (Diptera: Glossinidae) house a taxonomically diverse microbiota that includes environmentally acquired bacteria, maternally transmitted symbiotic bacteria, and pathogenic African trypanosomes. Sodalis glossinidius, which is a facultative symbiont that resides intra and extracellularly within multiple tsetse tissues, has been implicated as a mediator of trypanosome infection establishment in the fly's gut. Tsetse's gut-associated population of Sodalis are subjected to marked temperature fluctuations each time their ectothermic fly host imbibes vertebrate blood. The molecular mechanisms that Sodalis employs to deal with this heat stress are unknown. In this study, we examined the thermal tolerance and heat shock response of Sodalis. When grown on BHI agar plates, the bacterium exhibited the most prolific growth at 25oC, and did not grow at temperatures above 30oC. Growth on BHI agar plates at 31°C was dependent on either the addition of blood to the agar or reduction in oxygen levels. Sodalis was viable in liquid cultures for 24 hours at 30oC, but began to die upon further exposure. The rate of death increased with increased temperature. Similarly, Sodalis was able to survive for 48 hours within tsetse flies housed at 30oC, while a higher temperature (37oC) was lethal. Sodalis' genome contains homologues of the heat shock chaperone protein-encoding genes dnaK, dnaJ, and grpE, and their expression was up-regulated in thermally stressed Sodalis, both in vitro and in vivo within tsetse fly midguts. Arrested growth of E. coli dnaK, dnaJ, or grpE mutants under thermal stress was reversed when the cells were transformed with a low copy plasmid that encoded the Sodalis homologues of these genes. The information contained in this study provides insight into how arthropod vector enteric commensals, many of which mediate their host's ability to transmit pathogens, mitigate heat shock associated with the ingestion of a blood meal.


Assuntos
Enterobacteriaceae/crescimento & desenvolvimento , Enterobacteriaceae/fisiologia , Estresse Fisiológico , Temperatura Ambiente , Moscas Tsé-Tsé/microbiologia , Animais , Bactérias , Proteínas de Bactérias/genética , Técnicas de Cultura de Células , Enterobacteriaceae/genética , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos/genética , Cinética , Simbiose , Termotolerância , Trypanosoma
8.
Biol Lett ; 15(11): 20190566, 2019 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-31744411

RESUMO

Physiologists have primarily focused on two potential explanations for heat stress in animals-the classic model of molecular stability and an alternative model of oxygen limitation. Although the classic model has widespread support, the oxygen-supply model applies to many aquatic animals and some terrestrial ones. In particular, the embryonic stage of terrestrial animals seems most susceptible to oxygen limitation because embryos acquire oxygen from the atmosphere by diffusion rather than ventilation. We report experiments confirming the two conditions of the oxygen-supply model in Japanese quail embryos, Coturnix coturnix. Hypoxia (12% O2) greatly reduced the chance of survival at 47.5°C, and hyperoxia greatly improved the chance of survival at 48.5°C. This finding expands the scope of the oxygen-supply model to a terrestrial, endothermic species, suggesting that oxygen supply generally limits the heat tolerance of embryos.


Assuntos
Termotolerância , Animais , Coturnix , Hipóxia , Oxigênio , Consumo de Oxigênio
9.
Physiol Biochem Zool ; 92(6): 567-572, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31567049

RESUMO

Thermal physiology changes as organisms grow and develop, but we do not understand what causes these ontogenetic shifts. According to the theory of oxygen- and capacity-limited thermal tolerance, an organism's heat tolerance should change throughout ontogeny as its ability to deliver oxygen varies. As insects grow during an instar, their metabolic demand increases without a proportional increase in the size of tracheae that supply oxygen to the tissues. If oxygen delivery limits heat tolerance, the mismatch between supply and demand should make insects more susceptible to heat and hypoxia as they progress through an instar. We tested this hypothesis by measuring the heat tolerance of grasshoppers (Schistocerca americana) on the second and seventh days of the sixth instar, in either a normoxic or a hypoxic atmosphere (21% or 10% O2, respectively). As expected, heat tolerance decreased as grasshoppers grew larger. Yet contrary to expectation, hypoxia had no effect on heat tolerance across all stages and sizes. Although heat tolerance declines as grasshoppers grow, this pattern must stem from a mechanism other than oxygen limitation.


Assuntos
Gafanhotos/fisiologia , Temperatura Alta , Oxigênio/metabolismo , Termotolerância , Animais
10.
Biol Lett ; 15(10): 20190613, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31615371

RESUMO

The ability to cope with increasing and more variable temperatures, due to predicted climate changes, through plastic and/or evolutionary responses will be crucial for the persistence of Arctic species. Here, we investigate plasticity of heat tolerance of the Greenlandic seed bug Nysius groenlandicus, which inhabits areas with widely fluctuating temperatures. We test the heat tolerance and hardening capacity (plasticity) of N. groenlandicus using both static (heat knock down time, HKDT) and dynamic (critical thermal maximum, CTmax) assays. We find that N. groenlandicus is able to tolerate short-term exposure to temperatures up to almost 50°C and that it can quickly increase heat resistance following heat hardening. Furthermore, we find that this hardening response is reversible within hours after hardening. These findings contrast with common observations from temperate and tropical insects and suggest high thermal plasticity in some Arctic insects which enables them to cope with extreme temperature variability in their habitats.


Assuntos
Mariposas , Termotolerância , Aclimatação , Animais , Mudança Climática , Temperatura Alta , Temperatura Ambiente
11.
Nat Commun ; 10(1): 4031, 2019 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-31530800

RESUMO

Naturally heat-resistant coral populations hold significant potential for facilitating coral reef survival under rapid climate change. However, it remains poorly understood whether they can acclimatize to ocean warming when superimposed on their already thermally-extreme habitats. Furthermore, it is unknown whether they can maintain their heat tolerance upon larval dispersal or translocation to cooler reefs. We test this in a long-term mesocosm experiment using stress-resistant corals from thermally-extreme reefs in NW Australia. We show that these corals have a remarkable ability to maintain their heat tolerance and health despite acclimation to 3-6 °C cooler, more stable temperatures over 9 months. However, they are unable to increase their bleaching thresholds after 6-months acclimation to + 1 °C warming. This apparent rigidity in the thermal thresholds of even stress-resistant corals highlights the increasing vulnerability of corals to ocean warming, but provides a rationale for human-assisted migration to restore cooler, degraded reefs with corals from thermally-extreme reefs.


Assuntos
Aclimatação , Antozoários/fisiologia , Mudança Climática , Temperatura Ambiente , Animais , Oceanos e Mares , Estresse Fisiológico , Termotolerância/fisiologia
12.
J Econ Entomol ; 112(6): 2984-2992, 2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31504651

RESUMO

Tribolium castaneum (Herbst) ranks as one of the most prevalent insects in food processing and storage facilities worldwide. Heat treatment has been revisited to disinfest food processing and storage facilities due to increasingly strict regulation on chemicals. The effect of acclimation of T. castaneum larvae to sublethal high temperatures of 36 and 42℃ for 10 h on their heat adaptation was investigated, and transcript-level analysis combinating with real-time PCR (RT-qPCR) was applied for elucidating the heat adaptation mechanism of T. castaneum larvae. Short-term sublethal high temperature acclimation could greatly enhance the thermal adaptability in T. castaneum larvae. In total, 575, 875, and 1017 differentially expressed genes (DEGs) were, respectively, determined in comparisons between the 28 and 36℃ treatments, the 28 and 42℃ treatments, and the 36 and 42℃ treatments. Fifty-three and 96 genes were commonly up- and down-regulated in both the 36 and 42℃ treatments relative to 28℃, respectively. The results of RT-qPCR analysis further confirmed the RNA-seq analysis. The current results are in favor of enhancing the insecticidal effectiveness of extreme high temperature treatment and elucidating the heat adaptation mechanism in T. castaneum larvae.


Assuntos
Besouros , Termotolerância , Tribolium , Animais , Controle de Insetos , Larva , Reação em Cadeia da Polimerase em Tempo Real
13.
BMC Plant Biol ; 19(1): 398, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31510927

RESUMO

BACKGROUND: High temperature is one of the major abiotic stresses in tomato and greatly reduces fruit yield and quality. Identifying high-temperature stress-responsive (HSR) genes and breeding heat-tolerant varieties is an effective way to address this issue. However, there are few reports on the fine mapping of heat-tolerance quantitative trait locus (QTL) and the identification of HSR genes in tomato. Here, we applied three heat tolerance-related physiological indexes, namely, relative electrical conductivity (REC), chlorophyll content (CC) and maximum photochemical quantum efficiency (Fv/Fm) of PSII (photosystem II), as well as the phenotypic index, the heat injury index (HII), and conventional QTL analysis combined with QTL-seq technology to comprehensively detect heat-tolerance QTLs in tomato seedlings. In addition, we integrated the QTL mapping results with RNA-seq to identify key HSR genes within the major QTLs. RESULTS: A total of five major QTLs were detected: qHII-1-1, qHII-1-2, qHII-1-3, qHII-2-1 and qCC-1-5 (qREC-1-3). qHII-1-1, qHII-1-2 and qHII-1-3 were located, respectively, in the intervals of 1.43, 1.17 and 1.19 Mb on chromosome 1, while the interval of qHII-2-1 was located in the intervals of 1.87 Mb on chromosome 2. The locations observed with conventional QTL mapping and QTL-seq were consistent. qCC-1-5 and qREC-1-3 for CC and REC, respectively, were located at the same position by conventional QTL mapping. Although qCC-1-5 was not detected in QTL-seq analysis, its phenotypic variation (16.48%) and positive additive effect (0.22) were the highest among all heat tolerance QTLs. To investigate the genes involved in heat tolerance within the major QTLs in tomato, RNA-seq analysis was performed, and four candidate genes (SlCathB2, SlGST, SlUBC5, and SlARG1) associated with heat tolerance were finally detected within the major QTLs by DEG analysis, qRT-PCR screening and biological function analysis. CONCLUSIONS: In conclusion, this study demonstrated that the combination of conventional QTL mapping, QTL-seq analysis and RNA-seq can rapidly identify candidate genes within major QTLs for a complex trait of interest to replace the fine-mapping process, thus greatly shortening the breeding process and improving breeding efficiency. The results have important applications for the fine mapping and identification of HSR genes and breeding for improved thermotolerance.


Assuntos
Genes de Plantas/fisiologia , Temperatura Alta , Lycopersicon esculentum/fisiologia , Locos de Características Quantitativas/fisiologia , Termotolerância/genética , Mapeamento Cromossômico , Lycopersicon esculentum/genética , Análise de Sequência de RNA , Estresse Fisiológico
14.
Eur J Appl Physiol ; 119(10): 2391-2399, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31512025

RESUMO

PURPOSE: This study investigated the effects of a 10-day heat acclimation (HA) programme on the time course of changes in thermoneutral maximal oxygen uptake ([Formula: see text]O2max) during and up to 10 days post-HA. METHODS: Twenty-two male cyclists were assigned to a HA or control (Con) training group following baseline ramp tests of thermoneutral [Formula: see text]O2max. Ten days of fixed-intensity (50% baseline [Formula: see text]O2max) indoor cycling was performed in either ~ 38.0 °C (HA) or ~ 20 °C (Con). [Formula: see text]O2max was re-tested on HA days 5, 10 and post-HA days 1, 2, 3, 4, 5 and 10. RESULTS: [Formula: see text]O2max initially declined across time in both groups during training (P < 0.05), before increasing in the post-HA period in both groups (P < 0.05). However, [Formula: see text]O2max was higher than control by post-HA day 4 in the HA group (P = 0.046). CONCLUSIONS: The non-linear time course of [Formula: see text]O2max adaptation suggests that post-testing should be performed 96-h post-training to identify the maximal change for most individuals. In preparation for training or testing, athletes can augment their aerobic power in thermoneutral environments by performing 10 days HA, but the full effects will manifest at varying stages of the post-HA period.


Assuntos
Consumo de Oxigênio , Condicionamento Físico Humano/métodos , Termotolerância , Adulto , Temperatura Corporal , Humanos , Masculino , Tempo de Reação
15.
Cell Host Microbe ; 26(3): 385-399.e9, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31513773

RESUMO

Parasitic protists belonging to the genus Leishmania synthesize the non-canonical carbohydrate reserve, mannogen, which is composed of ß-1,2-mannan oligosaccharides. Here, we identify a class of dual-activity mannosyltransferase/phosphorylases (MTPs) that catalyze both the sugar nucleotide-dependent biosynthesis and phosphorolytic turnover of mannogen. Structural and phylogenic analysis shows that while the MTPs are structurally related to bacterial mannan phosphorylases, they constitute a distinct family of glycosyltransferases (GT108) that have likely been acquired by horizontal gene transfer from gram-positive bacteria. The seven MTPs catalyze the constitutive synthesis and turnover of mannogen. This metabolic rheostat protects obligate intracellular parasite stages from nutrient excess, and is essential for thermotolerance and parasite infectivity in the mammalian host. Our results suggest that the acquisition and expansion of the MTP family in Leishmania increased the metabolic flexibility of these protists and contributed to their capacity to colonize new host niches.


Assuntos
Glicosiltransferases/classificação , Glicosiltransferases/metabolismo , Leishmania/enzimologia , Manosiltransferases/metabolismo , Fosforilases/classificação , Fosforilases/metabolismo , Cristalografia por Raios X , Transferência Genética Horizontal , Glicosiltransferases/química , Glicosiltransferases/genética , Mananas , Manosiltransferases/química , Manosiltransferases/genética , Modelos Moleculares , Oligossacarídeos , Fosforilases/química , Fosforilases/genética , Conformação Proteica , Termotolerância , Virulência
16.
Int J Mol Sci ; 20(19)2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31547604

RESUMO

Activation and enhancement of heat shock factor (HSF) pathways are important adaptive responses to heat stress in plants. The γ-aminobutyric acid (GABA) plays an important role in regulating heat tolerance, but it is unclear whether GABA-induced thermotolerance is associated with activation of HSF pathways in plants. In this study, the changes of endogenous GABA level affecting physiological responses and genes involved in HSF pathways were investigated in creeping bentgrass during heat stress. The increase in endogenous GABA content induced by exogenous application of GABA effectively alleviated heat damage, as reflected by higher leaf relative water content, cell membrane stability, photosynthesis, and lower oxidative damage. Contrarily, the inhibition of GABA accumulation by the application of GABA biosynthesis inhibitor further aggravated heat damage. Transcriptional analyses showed that exogenous GABA could significantly upregulate transcript levels of genes encoding heat shock factor HSFs (HSFA-6a, HSFA-2c, and HSFB-2b), heat shock proteins (HSP17.8, HSP26.7, HSP70, and HSP90.1-b1), and ascorbate peroxidase 3 (APX3), whereas the inhibition of GABA biosynthesis depressed these genes expression under heat stress. Our results indicate GABA regulates thermotolerance associated with activation and enhancement of HSF pathways in creeping bentgrass.


Assuntos
Agrostis/metabolismo , Proteínas de Choque Térmico/metabolismo , Resposta ao Choque Térmico/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Termotolerância/efeitos dos fármacos , Ácido gama-Aminobutírico/farmacologia , Agrostis/genética , Proteínas de Choque Térmico/genética , Resposta ao Choque Térmico/fisiologia , Proteínas de Plantas/genética , Termotolerância/fisiologia
17.
Plant Physiol Biochem ; 143: 29-39, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31479880

RESUMO

The VQ motif-containing (VQ) proteins are plant-specific proteins with a conserved "FxxhVQxhTG" amino acid sequence, which regulate plant growth and development. Little is known, however, about the function of VQ proteins in tomato (Solanum lycopersicum). Here, a total of 26 SlVQ proteins were confirmed and characterized using a comprehensive genome-wide analysis. The SlVQ proteins all contain the conserved motif with seven variations, which are classified into eight groups (I, II, IV-VI, VIII-X). Most of them were predicted to be localized in the nucleus. Besides, a network including SlVQ proteins interaction with WRKY transcription factors (SlWRKYs) and mitogen-activated protein kinases (SlMPKs) is proposed. In addition, among the SlVQ genes, SlVQ6 was expressed in the range of organs and tissues with the highest levels and could response to different stresses. Ectopically overexpression of SlVQ6 in Arabidopsis plants decreased high temperature tolerance. RNA sequencing analysis revealed that several stress-related genes, such as HSP70-4, RD20, GolS1 and AT4g36010 were down-regulated in SlVQ6 overexpressing plants compared to these in wild-type under normal growth conditions. This study provides critical information about SlVQ genes and their encoded proteins, as well as further research on SlVQ functions in tomato growth and development.


Assuntos
Lycopersicon esculentum/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Genoma de Planta/genética , Lycopersicon esculentum/genética , Filogenia , Proteínas de Plantas/genética , Termotolerância/genética , Termotolerância/fisiologia
18.
Extremophiles ; 23(5): 599-612, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31376001

RESUMO

A novel thermophilic bacteriophage AP45 and its host strain Aeribacillus sp. CEMTC656 were isolated from the Valley of Geysers, Kamchatka Peninsula, Russia. Bacteriophage AP45 was identified as a member of the Siphoviridae family by electron microscopy. It showed high thermostability and had a slow cycle of reproduction. The AP45 genome had 51,606 base pairs (bp) and contained 71 open reading frames (ORFs), 40 of them encoding proteins of predicted function. Genes encoding DNA and RNA polymerases were not identified, indicating that AP45 used host polymerases. Based on the ORF65 encoding putative endolysin, the recombinant protein rAP45Lys was developed and its peptidoglycan-hydrolyzing activity was demonstrated. The AP45 genome exhibited limited identity to other phage sequences; the highest identity, 36%, was with the genome of the thermophilic Geobacillus myovirus D6E. The majority of putative proteins encoded by the AP45 genome had higher similarity to proteins from bacteria belonging to the Bacillaceae family, than to bacteriophages. In addition, more than half of the putative ORFs in the AP45 genome were highly similar to prophage sequences of A. pallidus strain 8m3, which was isolated in north-east China. The AP45 phage and revealed prophages might be members of a new genus belonging to the Siphoviridae family.


Assuntos
Bacillaceae/virologia , Genoma Viral , Siphoviridae/genética , Termotolerância , Fontes Termais/microbiologia , Fontes Termais/virologia , Fases de Leitura Aberta , Filogenia , Siphoviridae/classificação , Siphoviridae/patogenicidade
19.
Int J Mol Sci ; 20(15)2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31374822

RESUMO

The genotype WS-1, previously identified from novel wucai germplasm, is tolerant to both low-temperature (LT) and high-temperature (HT) stress. However, it is unclear which signal transduction pathway or acclimation mechanisms are involved in the temperature-stress response. In this study, we used the proteomic method of tandem mass tag (TMT) coupled with liquid chromatography-mass spectrometry (LC-MS/MS) to identify 1022 differentially expressed proteins (DEPs) common to WS-1, treated with either LT or HT. Among these 1022 DEPs, 172 were upregulated in response to both LT and HT, 324 were downregulated in response to both LT and HT, and 526 were upregulated in response to one temperature stress and downregulated in response to the other. To illustrate the common regulatory pathway in WS-1, 172 upregulated DEPs were further analyzed. The redox homeostasis, photosynthesis, carbohydrate metabolism, heat-shockprotein, and chaperones and signal transduction pathways were identified to be associated with temperature stress tolerance in wucai. In addition, 35S:BcccrGLU1 overexpressed in Arabidopsis, exhibited higher reduced glutathione (GSH) content and reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and less oxidative damage under temperature stress. This result is consistent with the dynamic regulation of the relevant proteins involved in redox homeostasis. These data demonstrate that maintaining redox homeostasis is an important common regulatory pathway for tolerance to temperature stress in novel wucai germplasm.


Assuntos
Brassica/fisiologia , Termotolerância , Brassica/genética , Resposta ao Choque Frio , Regulação da Expressão Gênica de Plantas , Resposta ao Choque Térmico , Homeostase , Oxirredução , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Mapas de Interação de Proteínas , Proteômica
20.
Environ Sci Pollut Res Int ; 26(28): 29490-29496, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31435907

RESUMO

Researchers dealing with heat stress experiments use different cell kinds and use trypsin that has been reported to affect the cellular proteins of cultured cells. Therefore, we compared the effects of acute and chronic exposures to high temperature (45 °C) on camel skin fibroblast and granulosa cells. Primary culture of fibroblasts and granulosa cells tolerated the acute heat shock for 2 h; however, granulosa cells cultured for long duration (20 h) showed thermotolerance when compared with the fibroblasts. Moreover, the effect of cell dispersion method (trypsin and mechanical dissociation) on the thermotolerance of sub-cultured cells was examined. Trypsin altered the morphology of fibroblasts and granulosa cells exposed to 45 °C for 4 h. Moreover, trypsin significantly reduced the fibroblast and granulosa cell migration in the wound healing assay. The current results demonstrate that cell passaging and cell type can affect the thermotolerance of the cells; it also revealed that trypsin could alter the cellular response to the heat shock. We raise the demand for another alternative method for cell dispersion in experiments dealing with cellular responses to the heat shock.


Assuntos
Fibroblastos/metabolismo , Células da Granulosa/metabolismo , Animais , Camelus , Células Cultivadas , Feminino , Febre/metabolismo , Fibroblastos/química , Células da Granulosa/química , Resposta ao Choque Térmico , Temperatura Alta , Termotolerância
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