Adaptive Development Research Articles

Reconstitution of the Jasmonate Signaling Pathway in Plant Protoplasts.

The phytohormone jasmonic acid (JA) plays an important role in various plant developmental processes and environmental adaptations. The JA signaling pathway has been well-elucidated in the reference plant Arabidopsis thaliana. It starts with the perception of the active JA derivative, jasmonoyl-isoleucine (JA-Ile), by the F-box protein COI1 which is part of the E3-ligase SCFCOI1. Binding of JA-Ile enables the interaction between COI1 and JAZ repressor proteins. Subsequent degradation of JAZ proteins leads to the activation of transcription factors like e.g., MYC2. Here we demonstrate that the pathway can be reconstituted in transiently transformed protoplasts. Analysis of the stability of a JAZ1-fLuc fusion protein as a function of COI1 transiently expressed in coi1 protoplasts allows structure function analysis of both JAZs and COI1. Using this system, we found that conserved cysteines in COI1 influence steady state COI1 protein levels. Using a luciferase reporter gene under the control of the JAZ1 promoter enable to address those features of JAZ1 that are required for MYC2 repression. Interestingly, the conserved TIFY-motif previously described to interact with NINJA to recruit the corepressor TOPLESS is not necessary for repression. This result is in favor of the alternative repression mode that proposes a direct competition between repressive JAZs and promotive MEDIATOR25 at MYC2. Finally, using protoplasts from the aos coi1 double mutant, which is deficient in JA synthesis and perception, we provide a system that has the potential to study the activity of different COI1 variants in the presence of different ligands.

Development and Open Trial of a Psychosocial Intervention for Young Children With Chronic Tics: The CBIT-JR Study

The Comprehensive Behavioral Intervention for Tic Disorders (CBIT) has demonstrated efficacy in large randomized controlled trials for children (≥9 yrs), adolescents and adults with Tourette Syndrome and Chronic Tic Disorders. Given the early age of onset for tic disorders, a large portion of affected individuals with chronic tic disorders are less than 9 years of age and appropriate developmental adaptations of behavioral treatment have not yet been tested. The goal of this study was to adapt and evaluate the acceptability and utility of a family-based adaptation of CBIT for children under 9 years of age. Children 5–8 years of age (N = 15) with chronic tics were recruited from three study sites. CBIT was adapted for use with young children and included habit reversal strategies introduced in a developmentally appropriate game format and function-based interventions to reduce family accommodation of and attention to tic symptoms.Children and parents described high level of treatment satisfaction and study retention rate was 100%. Treatment response rate was 54% (CGI-I = 1 or 2) with a significant decrease in the YGTSS total score (Cohen’s d = 0.73) that was largely maintained at 3-month and 1-year follow-up assessments. Treatment was associated with reduction of some symptoms of tic-related comorbid syndromes and with changes in parental accommodation and attention to tics.Future research should determine if parental attention to tics and symptom accommodation are important mediators of treatment outcome, or if participating in this intervention at a younger age may prevent the chronic course of tic symptoms.

Occurrence and Functions of m6A and Other Covalent Modifications in Plant mRNA.

Posttranscriptional control of gene expression is indispensable for the execution of developmental programs and environmental adaptation. Among the many cellular mechanisms that regulate mRNA fate, covalent nucleotide modification has emerged as a major way of controlling the processing, localization, stability, and translatability of mRNAs. This powerful mechanism is conserved across eukaryotes and controls the cellular events that lead to development and growth. As in other eukaryotes, N 6-methylation of adenosine is the most abundant and best studied mRNA modification in flowering plants. It is essential for embryonic and postembryonic plant development and it affects growth rate and stress responses, including susceptibility to plant RNA viruses. Although the mRNA modification field is young, the intense interest triggered by its involvement in stem cell differentiation and cancer has led to rapid advances in understanding how mRNA modifications control gene expression in mammalian systems. An equivalent effort from plant molecular biologists has been lagging behind, but recent work in Arabidopsis (Arabidopsis thaliana) and other plant species is starting to give insights into how this essential layer of posttranscriptional regulation works in plants, and both similarities and differences with other eukaryotes are emerging. In this Update, we summarize, connect, and evaluate the experimental work that supports our current knowledge of the biochemistry, molecular mechanisms, and biological functions of mRNA modifications in plants. We devote particular attention to N 6-methylation of adenosine and attempt to place the knowledge gained from plant studies within the context of a more general framework derived from studies in other eukaryotes.

Biochemical and molecular changes mediated by plasticizer diethyl phthalate in Chironomus circumdatus (bloodworms)

Plasticizers are used as additives in making plastics. Diethyl phthalate (DEP) is one of the majorly used plasticizers in various products. When plastic materials are dumped in an aquatic system, there is an increase in chances of DEP leaching out and getting deposited in water. Thus the current work focuses on studying the effect of DEP on the larval stages of Chironomus circumdatus. In this study it was found that there was an increase in lipid peroxidation levels indicating imposition of oxidative stress on these larvae due to the exposure of DEP. Changes in the levels of carbohydrates and lipids were also seen. To reduce these effects antioxidant defense system may get activated. Thus investigations showed an increase in enzymatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and acetylcholinesterases (AchE) and decrease in the activity of glutathione reductase (GR). Nonenzymatic antioxidant glutathione levels were also increased during the post-recovery exposure period. Thus this indicates that both enzymatic, as well as non-enzymatic antioxidants, play a certain role in reducing the stress mediated by DEP. Up-regulation of gene expression of heat shock protein70 (hsp70) was observed, which is one of the conserved protein produced during stress response in many dipterans. Changes in the level of expression of the ecdysone receptor (EcR) gene were also seen in DEP exposed larvae. Thus the insights give us a preliminary indication that physiological and developmental adaptations may take place in these organisms to persist in the DEP contaminated environment. CapsuleDEP mediated stress imposes changes in the metabolites and thus activation of antioxidant defense system in aquatic midges of Chironomus circumdatus. Changes in the expression of heat shock protein70 and ecdysone receptor was also seen indicating that DEP mediated stress affects at the molecular level also of the organism. These changes may help them to tolerate and live in DEP polluted water.

A Customizable Approach for the Enzymatic Production and Purification of Diterpenoid Natural Products.

Diterpenoids form a diverse class of small molecule natural products that are widely distributed across the kingdoms of life and have critical biological functions in developmental processes, interorganismal interactions, and environmental adaptation. Due to these various bioactivities, many diterpenoids are also of economic importance as pharmaceuticals, food additives, biofuels, and other bioproducts. Advanced genomics and biochemical approaches have enabled a rapid increase in the knowledge of diterpenoid-metabolic genes, enzymes, and pathways. However, the structural complexity of diterpenoids and the narrow taxonomic distribution of individual compounds in often only a single species remain constraining factors for their efficient production. Availability of a broader range of metabolic enzymes now provide resources for producing diterpenoids in sufficient titers and purity to facilitate a deeper investigation of this important metabolite group. Drawing on established tools for microbial and plant-based enzyme co-expression, we present an easily operated and customizable protocol for the enzymatic production of diterpenoids in either Escherichia coli or Nicotiana benthamiana, and the purification of desired products via silica chromatography and semi-preparative HPLC. Using the group of maize (Zea mays) dolabralexin diterpenoids as an example, we highlight how modular combinations of diterpene synthase (diTPS) and cytochrome P450 monooxygenase (P450) enzymes can be used to generate different diterpenoid scaffolds. Purified compounds can be used in various downstream applications, such as metabolite structural analyses, enzyme structure-function studies, and in vitro and in planta bioactivity experiments.

Adolescent and Parent Experiences of Acceptance and Commitment Therapy for Pediatric Chronic Pain: An Interpretative Phenomenological Analysis.

Pediatric chronic pain is common and can be related to reduced functioning in many domains for the young person and their parents. Existing psychological treatments such as Acceptance and Commitment Therapy (ACT) have shown to be effective, but improvements are needed. Qualitative approaches can help improve our understanding of treatment processes and outcomes. The aim of the present qualitative interview study was to explore the lived experiences of young people and parents who had participated in ACT for pediatric chronic pain. Four young persons and four parents were interviewed, and data was analyzed using Interpretative Phenomenological Analysis (IPA). Three themes were generated, each comprising two subthemes: (1) ‘Warning system’, which included experiences from being offered this psychological intervention, and the alternative explanations provided for pain; (2) ‘Change and challenges’, which suggested the importance of the values-based work, and of individual adaptation; and (3) ’A common language’ in which the interaction with others and new ways to communicate around the pain experience were described. Findings highlight the importance of pain education, formulating and acting in line with personal values, and communication around the pain experience, as well as the need for developmental and individual adaptations of interventions.

Small RNA Mobility: Spread of RNA Silencing Effectors and its Effect on Developmental Processes and Stress Adaptation in Plants.

Plants are exposed every day to multiple environmental cues, and tight transcriptome reprogramming is necessary to control the balance between responses to stress and processes of plant growth. In this context, the silencing phenomena mediated by small RNAs can drive transcriptional and epigenetic regulatory modifications, in turn shaping plant development and adaptation to the surrounding environment. Mounting experimental evidence has recently pointed to small noncoding RNAs as fundamental players in molecular signalling cascades activated upon exposure to abiotic and biotic stresses. Although, in the last decade, studies on stress responsive small RNAs increased significantly in many plant species, the physiological responses triggered by these molecules in the presence of environmental stresses need to be further explored. It is noteworthy that small RNAs can move either cell-to-cell or systemically, thus acting as mobile silencing effectors within the plant. This aspect has great importance when physiological changes, as well as epigenetic regulatory marks, are inspected in light of plant environmental adaptation. In this review, we provide an overview of the categories of mobile small RNAs in plants, particularly focusing on the biological implications of non-cell autonomous RNA silencing in the stress adaptive response and epigenetic modifications.

Effects of maize organ-specific drought stress response on yields from transcriptome analysis

BackgroundDrought is a serious causal factor of reduced crop yields than any other abiotic stresses. As one of the most widely distributed crops, maize plants frequently suffer from drought stress, which causes great losses in the final kernel yield. Drought stress response in plants showed tissue- and developmental stage-specific characteristics.ResultsIn this study, the ears at the V9 stage, kernels and ear leaf at the 5DAP (days after pollination) stage of maize were used for morphological, physiological and comparative transcriptomics analysis to understand the different features of “sink” or “source” organs and the effects on kernel yield under drought stress conditions. The ABA-, NAC-mediate signaling pathway, osmotic protective substance synthesis and protein folding response were identified as common drought stress response in the three organs. Tissue-specific drought stress responses and the regulators were identified, they were highly correlated with growth, physiological adaptation and yield loss under drought stress. For ears, drought stress inhibited ear elongation, led to the abnormal differentiation of the paired spikelet, and auxin signaling involved in the regulation of cell division and growth and primordium development changes. In the kernels, reduced kernel size caused by drought stress was observed, and the obvious differences of auxin, BR and cytokine signaling transduction appeared, which indicated the modification in carbohydrate metabolism, cell differentiation and growth retardation. For the ear leaf, dramatically and synergistically reduced the expression of photosynthesis genes were observed when suffered from drought stress, the ABA- and NAC- mediate signaling pathway played important roles in the regulation of photosynthesis.ConclusionsTranscriptomic changes caused by drought were highly correlated with developmental and physiological adaptation, which was closely related to the final yield of maize, and a sketch of tissue- and developmental stage-specific responses to drought stress in maize was drafted.

Pathways to social-emotional functioning in the preschool period: The role of child temperament and maternal anxiety in boys and girls

Individual differences in social-emotional functioning emerge early and have long-term implications for developmental adaptation and competency. Research is needed that specifies multiple early risk factors and outcomes simultaneously to demonstrate specificity. Using multigroup longitudinal path analysis in a sample of typically developing children (N = 541), we examined child temperament dimensions (surgency, negative affectivity, and regulation/effortful control) and maternal anxiety in infancy and age 2 as predictors of child externalizing, internalizing, dysregulation, and competence behaviors at age 3. Four primary patterns emerged. First, there was stability in temperament dimensions and maternal anxiety from infancy to age 3. Second, negative affectivity was implicated in internalizing problems and surgency in externalizing problems. Third, effortful control at age 2 was a potent mediator of maternal anxiety in infancy on age 3 outcomes. Fourth, there was suggestive evidence for transactional effects between maternal anxiety and child effortful control. Most pathways operated similarly for boys and girls, with some differences, particularly for surgency. These findings expand our understanding of the roles of specific temperamental domains and postnatal maternal anxiety in a range of social-emotional outcomes in the preschool period, and have implications for efforts to enhance the development of young children's social-emotional functioning and reduce risk for later psychopathology.

Genome Wide Identification, Molecular Characterization, and Gene Expression Analyses of Grapevine NHX Antiporters Suggest Their Involvement in Growth, Ripening, Seed Dormancy, and Stress Response.

Plant NHX antiporters are critical for cellular pH, Na+, and K+ homeostasis and salt tolerance. Even though their genomic and functional studies have been conducted in many species, the grapevine NHX family has not been described yet. Our work highlights the presence of six VvNHX genes whose phylogenetic analysis revealed their classification in two distinct groups: group I vacuolar (VvNHX1-5) and group II endosomal (VvNHX6). Several cis-acting regulatory elements related to tissue-specific expression, transcription factor binding, abiotic/biotic stresses response, and light regulation elements were identified in their promoter. Expression profile analyses of VvNHX genes showed variable transcription within organs and tissues with diverse patterns according to biochemical, environmental, and biotic treatments. All VvNHXs are involved in berry growth, except VvNHX5 that seems to be rather implicated in seed maturation. VvNHX4 would be more involved in floral development, while VvNHX2 and 3 display redundant roles. QPCR expression analyses of VvNHX1 showed its induction by NaCl and KNO3 treatments, whereas VvNHX6 was induced by ABA application and strongly repressed by PEG treatment. VvNHX1 plays a crucial role in a bunch of grape developmental steps and adaptation responses through mechanisms of phyto-hormonal signaling. Overall, VvNHX family members could be valuable candidate genes for grapevine improvement.

Nutritional adversity, sex and reproduction: 30 years of DOHaD and what have we learned?

It is well established that early life environmental signals, including nutrition, set the stage for long-term health and disease risk - effects that span multiple generations. This relationship begins early, in the periconceptional period and extends into embryonic, fetal and early infant phases of life. Now known as the Developmental Origins of Health and Disease (DOHaD), this concept describes the adaptations that a developing organism makes in response to early life cues, resulting in adjustments in homeostatic systems that may prove maladaptive in postnatal life, leading to an increased risk of chronic disease and/or the inheritance of risk factors across generations. Reproductive maturation and function is similarly influenced by early life events. This should not be surprising, since primordial germ cells are established early in life and thus vulnerable to early life adversity. A multitude of 'modifying' cues inducing developmental adaptations have been identified that result in changes in reproductive development and impairments in reproductive function. Many types of nutritional challenges including caloric restriction, macronutrient excess and micronutrient insufficiencies have been shown to induce early life adaptations that produce long-term reproductive dysfunction. Many pathways have been suggested to underpin these associations, including epigenetic reprogramming of germ cells. While the mechanisms still remain to be fully investigated, it is clear that a lifecourse approach to understanding lifetime reproductive function is necessary. Furthermore, investigations of the impacts of early life adversity must be extended to include the paternal environment, especially in epidemiological and clinical studies of offspring reproductive function.

Genome-wide characterization of the WRKY gene family in cultivated strawberry (Fragaria\u2009\xd7\u2009ananassa Duch.) and the importance of several group III members in continuous cropping

WRKY transcription factors play important roles in many plant developmental processes and adaptation to the environment. However, little knowledge is available about the WRKY gene family in cultivated strawberry (Fragaria × ananassa Duch.), an important soft fruit worldwide. In this study, a total of 47 WRKY gene members were identified and renamed on the basis of their order on the chromosomes. According to their evolutionary events and conserved structure, the 47 FaWRKYs were divided into three major groups with several subgroups. A cis-element analysis showed that all FaWRKYs possessed at least one stress response-related cis-element. Comprehensive analysis, including phylogenetic analysis and expression profiling, based on real-time qPCR analysis in root, stem, leaf and fruit was performed on group III FaWRKY genes. The phylogenetic tree of the WRKY III genes in cultivated strawberry, wild Strawberry, Arabidopsis, tomato, and rice was divided into five clades. Additionally, the expression profiles of the FaWRKY genes in response to continuous cropping were further investigated based on RNA-seq data. FaWRKY25, FaWRKY32, and FaWRKY45, which are group III FaWRKY genes, were upregulated after continuous cropping. The level of reactive oxygen species (ROS) and the expression levels of PR1 and peroxidase were higher in continuous cropping (CC) than in non-continuous cropping (NCC). The results indicated that group III FaWRKYs might play an important role in continuous cropping. These results provide a foundation for genetic improvements for continuous cropping tolerance in cultivated strawberry.

Genetic Deficiency of Flavin-Containing Monooxygenase 3 ( Fmo3) Protects Against Thrombosis but Has Only a Minor Effect on Plasma Lipid Levels-Brief Report.

Objective- FMO (flavin-containing monooxygenase) 3 converts bacterial-derived trimethylamine to trimethylamine N-oxide (TMAO), an independent risk factor for cardiovascular disease. We generated FMO3 knockout (FMO3KO) mouse to study its effects on plasma TMAO, lipids, glucose/insulin metabolism, thrombosis, and atherosclerosis. Approach and Results- Previous studies with an antisense oligonucleotide (ASO) knockdown strategy targeting FMO3 in LDLRKO (low-density lipoprotein receptor knockout) mice resulted in major reductions in TMAO levels and atherosclerosis, but also showed effects on plasma lipids, insulin, and glucose. Although FMO3KO mice generated via CRISPR/Cas9 technology bred onto the LDLRKO background did exhibit similar effects on TMAO levels, the effects on lipid metabolism were not as pronounced as with the ASO knockdown model. These differences could result from either off-target effects of the ASO or from a developmental adaptation to the FMO3 deficiency. To distinguish these possibilities, we treated wild-type and FMO3KO mice with control or FMO3 ASOs. FMO3-ASO treatment led to the same extent of lipid-lowering effects in the FMO3KO mice as the wild-type mice, indicating off-target effects. The levels of TMAO in LDLRKO mice fed an atherogenic diet are very low in both wild-type and FMO3KO mice, and no significant effect was observed on atherosclerosis. When FMO3KO and wild-type mice were maintained on a 0.5% choline diet, FMO3KO showed a marked reduction in both TMAO and in vivo thrombosis potential. Conclusions- FMO3KO markedly reduces systemic TMAO levels and thrombosis potential. However, the previously observed large effects of an FMO3 ASO on plasma lipid levels appear to be due partly to off-target effects.

Improved drought stress tolerance in Arabidopsis by CRISPR/dCas9 fusion with a Histone AcetylTransferase

Drought episodes decrease plant growth and productivity, which in turn cause high economic losses. Plants naturally sense and respond to water stress by activating specific signalling pathways leading to physiological and developmental adaptations. Genetically engineering genes that belong to these pathways might improve the drought tolerance of plants. The abscisic acid (ABA)-responsive element binding protein 1/ABRE binding factor (AREB1/ABF2) is a key positive regulator of the drought stress response. We investigated whether the CRISPR activation (CRISPRa) system that targets AREB1 might contribute to improve drought stress tolerance in Arabidopsis. Arabidopsis histone acetyltransferase 1 (AtHAT1) promotes gene expression activation by switching chromatin to a relaxed state. Stable transgenic plants expressing chimeric dCas9HAT were first generated. Then, we showed that the CRISPRa dCas9HAT mechanism increased the promoter activity controlling the β-glucuronidase (GUS) reporter gene. To activate the endogenous promoter of AREB1, the CRISPRa dCas9HAT system was set up, and resultant plants showed a dwarf phenotype. Our qRT-PCR experiments indicated that both AREB1 and RD29A, a gene positively regulated by AREB1, exhibited higher gene expression than the control plants. The plants generated here showed higher chlorophyll content and faster stomatal aperture under water deficit, in addition to a better survival rate after drought stress. Altogether, we report that CRISPRa dCas9HAT is a valuable biotechnological tool to improve drought stress tolerance through the positive regulation of AREB1.

24-epibrassinolide pre-treatment alleviates the salt-induced deleterious effects in medicinal pumpkin (Cucurbita pepo) by enhancement of GABA content and enzymatic antioxidants

It is known that epibrassinolide (EBL) plays an important role in the variety of plant developmental processes and adaptation to various environmental stresses. Salt stress is one of the most important environmental problems which limit crop growth and productivity. Here, the effects of EBL pretreatment on amelioration of the adverse effects of salinity were investigated in pumpkin, especially at the establishment stage. For this purpose, uniform-sized seedlings were transplanted to plastic containers containing one-half-strength Hoagland's nutrient solution. EBL was added at 0.1 and 0.01 μM to the hydroponic medium for 5 days before stress. The plants were treated with 40 and 80 mM NaCl for inducing salinity stress. Salt stress reduced the plant growth, calcium and potassium content in leaves and roots, and these detrimental effects were alleviated when plants were pretreated with EBL. Salinity stress caused a significant increase in lipid peroxidation, sodium, and γ-amino butyric acid (GABA) content. EBL pretreatment ameliorated these effects by reducing lipid peroxidation, sodium content and increasing GABA content. The increase in activities of guaiacol peroxidase, catalase, ascorbate peroxidase, and superoxide dismutase was observed under salinity stress. Application of exogenous EBL pretreatment further increased antioxidant enzymes activities. The present work emphasizes the protective role of EBL in the regulation of antioxidant enzymes and GABA accumulation and its possible link in amelioration of stress in plants. This is the first report dealing with EBL effect on GABA content under salt stress.

Phenotypic and molecular traits determine the tolerance of olive trees to drought stress

Olive trees are known for their capacity to adapt to drought through several phenotypic and molecular variations, although this can vary according to the different provenances of the same olive cultivar. We confronted the same olive cultivar from two different location in Spain: Freila, in the Granada province, with low annual precipitation, and Grazalema, in the Cadiz province, with high annual precipitation, and subjected them to five weeks of severe drought stress. We found distinctive physiological and developmental adaptations among the two provenances. Thus, trees from Freila subjected to drought stress exhibited increasing root dry weights and decreasing leaf numbers and relative stem heights. On the other hand, the treatment with drought in Grazalema trees reduced their leaf chlorophyll contents, but increased their relative stem diameter and their root hydraulic conductivity. The physiological responses of Freila tree roots to drought were linked to different molecular adaptations that involved the regulation of genes related to transcription factors induced by ABA, auxin and ethylene signaling, as well as, the action of a predicted membrane intrinsic protein (MIP). On the other hand, the responses of Grazalema trees were related with different root genes related to oxidation-reduction, ATP synthesis, transduction and posttranslational regulation, with a special mention to the cytokinins signaling through the transcript predicted as a histidine-containing phosphotransfer protein. Our results show that olive trees adapted to dry environments will adjust their growth and water uptake capacity through transcription factors regulation, and this will influence the different physiological responses to drought stress.

Maternal psychological distress during pregnancy and childhood cardio-metabolic risk factors

Background and aimsPrevious studies suggest that psychological distress during pregnancy may lead to fetal developmental adaptations, which programme cardio-metabolic disease of the offspring. We examined the associations of maternal overall psychological distress, depression and anxiety during pregnancy with cardio-metabolic risk factors in 10-year-old children and explore potential sex-specific differences. Methods and resultsIn a population-based prospective cohort study among 4,088 mothers and their children, information about overall psychological distress, including depression and anxiety was obtained through the Brief Symptom Inventory during pregnancy. We measured child blood pressure and heart rate and insulin, glucose, serum lipids and C-reactive protein blood concentrations at 10 years. Analyses were performed in the total group and in boys and girls separately. Psychological distress during pregnancy was associated with higher childhood heart rate among boys only (differences 0.34 (95% Confidence Interval (CI) 0.18, 0.50) standard deviation scores (SDS), 0.22 (95% CI 0.06, 0.38) SDS, 0.33 (95% CI 0.19, 0.48) SDS, for overall psychological distress, depression and anxiety, respectively). Maternal anxiety during pregnancy was associated with higher childhood triglycerides among girls (difference 0.35 (95% CI 0.17, 0.53) SDS). Maternal psychological distress was not associated with childhood blood pressure, cholesterol, insulin, glucose and C-reactive protein concentrations. ConclusionsMaternal psychological distress may influence their offspring heart rate and triglycerides concentrations. Further studies are needed to replicate these findings and assess the long-term cardio-metabolic consequences of maternal psychological distress.

Maternal high-fat diet impairs leptin signaling and up-regulates type-1 cannabinoid receptor with sex-specific epigenetic changes in the hypothalamus of newborn rats

Maternal nutritional imbalances trigger developmental adaptations involving early epigenetic mechanisms associated with adult chronic disease. Maternal high-fat (HF) diet promotes obesity and hypothalamic leptin resistance in male rat offspring at weaning and adulthood. Leptin resistance is associated with over activation of the endocannabinoid system (ECS). The ECS mainly consists of endocannabinoids derived from n-6 fatty acids and cannabinoid receptors (CB1 coded by Cnr1 and CB2 coded by Cnr2). The CB1 activation in hypothalamus stimulates feeding and appetite for fat while CB2 activation seems to play an immunomodulatory role. We demonstrated that maternal HF diet increases hypothalamic CB1 in male offspring while increases CB2 in female offspring at birth, prior to obesity development. However, the molecular mechanisms behind these changes remain unexplored. We hypothesized that maternal HF diet would down-regulate leptin signaling and up-regulate Cnr1 mRNA levels in the hypothalamus of the offspring at birth, associated with sex-specific changes in epigenetic markers and sex steroid signaling. To test our hypothesis, we used progenitor female rats that received control diet (C, 9% fat) or isocaloric high-fat diet (HF, 28% fat) from 8 weeks before mating until delivery. Blood, hypothalamus and carcass from C and HF male and female offspring were collected for biochemical and molecular analyses at birth. Maternal HF diet down-regulated the transcriptional factor STAT3 in the hypothalamus of male and female offspring, but induced hypoleptinemia only in males and decreased phosphorylated STAT3 only in female offspring. Because leptin acts through STAT3 pathway to inhibit central ECS, our results suggest that leptin pathway impairment might contribute to increased levels of Crn1 mRNA in hypothalamus of both sex offspring. Besides, maternal HF diet increased the histone acetylation percentage of Cnr1 promoter in male offspring and increased the androgen receptor binding to the Cnr1 promoter, which can contribute to higher expression of Cnr1 in newborn HF offspring. Maternal HF diet increased plasma n6 to n3 fatty acid ratio in male offspring, which is an important risk factor to metabolic diseases and might indicate an over activation of endocannabinoid signaling. Thus, although maternal HF diet programs a similar phenotype in adult offspring of both sexes (obesity, hyperphagia and higher preference for fat), here we showed that molecular mechanisms involving leptin signaling, ECS, epigenetic markers and sex hormone signaling were modified prior to obesity development and can differ between newborn male and female offspring. These observations may provide molecular insights into sex-specific targets for anti-obesity therapies.

米槁幼苗光合作用及光响应曲线模拟对干旱胁迫的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 米槁幼苗光合作用及光响应曲线模拟对干旱胁迫的响应 DOI: 10.5846/stxb201802140372 作者: 作者单位: 贵州大学林学院,贵州大学林学院,贵州大学林学院,贵州大学林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 贵州省科技计划（黔科合SY[2015]3023-1） Simulated photosynthetic responses of Cinnamomum migao during drought stress evaluated using Light-response Models Author: Affiliation: Guizhou University College of Forestry,Guizhou University College of Forestry,Guizhou University College of Forestry,Guizhou University College of Forestry Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为阐明米槁光合作用对干旱胁迫的响应规律与适应机制，以一年生米槁幼苗为研究对象，进行盆栽试验研究设置3种不同土壤含水量梯度，利用Li-6400便携式光合作用系统测定干旱胁迫下的光合生理指标及光响应过程，光响应曲线模拟采用直角双曲线模型、非直角双曲线模型、指数模型和直角双曲线修正模型进行拟合并对比，以期选出适用于干旱环境下的光响应模型。结果表明（1）光响应曲线模型对干旱胁迫下米槁幼苗的光合作用拟合中直角双曲线、非直角双曲线和指数模型适用于低光合有效辐射（PAR），但拟合光响应参数与实测值相差大，只有直角双曲线修正模型能够很好的拟合各个处理且拟合参数比较精确米槁幼苗。（2）光合作用的表观量子效率（Φ）小于一般植物的光合量子效率，则其对弱光的光能利用效率相对较低。（3）在较强的光合有效辐射条件下，严重干旱胁迫下的米槁净光合速率Pn显著下降，出现了明显的光抑制现象；中度胁迫下净光合速率（Pn）、最大净光合速率（Pnmax）、光补偿点（LSP）最大，米槁具有较宽的抗旱适应范围，有一定的抗旱性；严重胁迫下Pn、Pnmax、LSP降低，蒸腾速率（Tr）与气孔导度（Gs）下降幅度更大，但仍具有较高的水分利用效率（WUE），米槁在严重的干旱胁迫下光合机构受到一定的损伤，但自身可以通过生理调节来积极适应不良环境，减少光合机构伤害。（4）综合来看，在人工管理或种植米槁时，为了适应米槁生长发育，建议土壤含水量保持在23.05%到14.92%之间。 Abstract:The objective of this study was to elucidate the response and adaptation mechanisms of Cinnamomum migao seedlings to drought stress. Using pot experiments, we examined the effects of three relative water levels on the growth of 1-year-old C. migao seedlings by measuring photosynthetic physiological indices and light responses under drought stress. The responses were analyzed in terms of four different light response curve models:rectangular hyperbola, non-rectangular hyperbola, exponential, and modified rectangular hyperbola. The following results were obtained. (1) According to the values of photosynthetic parameters calculated using the four models, the rectangular hyperbola, non-rectangular hyperbola, and exponential models were suitable for low photosynthetically active radiation. However, only the modified rectangular hyperbola model provided a good fit for each treatment and the fitting parameters were more accurate. (2) The apparent quantum efficiency (Φ) of photosynthesis of drought-stressed plants was smaller than that of normal plants, and therefore the utilization efficiency of these plants is lower. (3) The net photosynthetic rate (Pn) of severely stressed C. migao plants decreased significantly under strong photosynthetically active radiation, whereas values for the net photosynthetic rate (Pn), maximum net photosynthetic rate (Pnmax), and light compensation point were the highest under conditions of moderate stress. C. migao has a wide range of stress tolerance. Under severe stress, Pn, Pnmax, and LSP decreased, and transpiration rate (Tr) and stomatal conductance (Gs) decreased more significantly; however, the plants still had a higher water-use efficiency. Although C. migao plants suffer damage under severe drought stress, they can adjust to the adverse environments through physiological modification and by reducing damage to their photosynthetic apparatus. (4) In order to facilitate growth and developmental adaptation in C. migao during management, it is recommended that the soil moisture content be maintained at levels between 23.05% and 14.92%. 参考文献 相似文献 引证文献

Embryogenesis of Marsupial Frogs (Hemiphractidae), and the Changes that Accompany Terrestrial Development in Frogs.

The developmental adaptations of the marsupial frogs Gastrotheca riobambae and Flectonotus pygmaeus (Hemiphractidae) are described and compared with frogs belonging to seven additional families. Incubation of embryos by the mother in marsupial frogs is associated with changes in the anatomy and physiology of the female, modifications of oogenesis, and extraordinary changes in embryonic development. The comparison of early development reveals that gene expression is highly conserved. However, the timing of gene expression varies between frog species. There are two modes of gastrulation according to the onset of convergent extension. In gastrulation mode 1, convergent extension is an intrinsic mechanism of gastrulation. This gastrulation mode occurs in frogs with aquatic reproduction, such as Xenopus laevis. In gastrulation mode 2, convergent extension occurs after the completion of gastrulation movements. Gastrulation mode 2 occurs in frogs with terrestrial reproduction, such as the marsupial frog, G. riobambae. The two modes of frog gastrulation resemble the two transitions toward meroblastic cleavage of ray-finned fishes (Actinopterygii). The comparison indicates that a major event in the evolution of frog terrestrial development is the separation of convergent extension from gastrulation.