Transcriptional Response of Two Core Photosystem Genes in Symbiodinium spp. Exposed to Thermal Stress

Mutualistic symbioses between scleractinian corals and endosymbiotic dinoflagellates (Symbiodinium spp.) are the foundation of coral reef ecosystems. For many coral-algal symbioses, prolonged episodes of thermal stress damage the symbiont's photosynthetic capability, resulting in its expulsion from the host. Despite the link between photosynthetic competency and symbiont expulsion, little is known about the effect of thermal stress on the expression of photosystem genes in Symbiodinium. This study used real-time PCR to monitor the transcript abundance of two important photosynthetic reaction center genes, psbA(encoding the D1 protein of photosystem II) and psaA (encoding the P700 protein of photosystem I), in four cultured isolates (representing ITS2-types A13, A20, B1, and F2) and two in hospite Symbiodinium spp. within the coral Pocillopora spp. (ITS2-types C1b-c and D1). Both cultured and in hospite Symbiodinium samples were exposed to elevated temperatures (32°C) over a 7-day period and examined for changes in photochemistry and transcript abundance. Symbiodinium A13 and C1b-c (both thermally sensitive) demonstrated significant declines in both psbA and psaA during the thermal stress treatment, whereas the transcript levels of the other Symbiodinium types remained stable. The downregulation of both core photosystem genes could be the result of several different physiological mechanisms, but may ultimately limit repair rates of photosynthetic proteins, rendering some Symbiodinium spp. especially susceptible to thermal stress.

As relações de interação e integração entre cérebro, corpo-propriamente-dito e meio-ambiente na constituição da mente consciente

This dissertation will be marked by our proposal to hold a theoretical perspective to the classical mind-body problem, and more precisely for the defense of the idea that consciousness (or conscious mind) emerges from the interaction and integration relationships between body proper, brain and environment. This purpose will lead us to assume an alternative position with respect to the more traditional perspectives to the mind-body problem, ie an alternative perspective not only in relation to the dualistics forms of mind-body, but also in regards to the reductive physicalists, which usually reduces mind to brain. Aiming to support a position that both avoid the idea that mind and body are distinct substances and the theory that the brain explains the consciousness in its totality, we will dedicate an important part of this work to explain how the structure of consciousness depends significantly of the body proper and the bodily information mechanisms as well as the environment and the physiological mechanisms through which we place ourselves in space, in front of us and the other bodies (organic and inorganic). Given that the relationship between brain, body and environment involves different mental levels — from the most primitive and unconscious mental mechanisms until conscious and sophisticated levels — we will proceed to the task of assuming a model to explain in what sense these levels contribute to that our instincts and the most sophisticated dimensions of our mental life are part of the one and the same process, which is why we will structure our argument from the ideia that mind, self, and consciousness are the different hierarchical levels which make up the totality of our psychic life and therefore organic one. Imbued with this conceptual approach, we will advance to the focus of this work, namely the reasons that will lead us to give a prominent role to the body proper and the environment in the constitution of the conscious mind, or even the reasons that will lead us to defend the thesis according to which we are embodied and situated, as well as the reasons that will lead us to reject the theoretical positions that dichotomize man and world. In order to support the thesis that we are embodied and situated, and therefore with the purpose of overcoming the theoretical paradigms that dichotomize consciousness and world, we will turn out to the authors and the perspectives we believe to be more successful in this endeavor, including the phenomenological approaches to bodily self-consciousness, the enactivists perspectives and the researches dedicated to mapping the interaction and integration relationships between brain, body and environment. To achieve our goals, the dissertation will be divided into two chapters: the first chapter will emphasize in what way the structuring of consciousness depends on the body proper and the environment, while in the second chapter we will resort to the phenomenological dimensions of bodily self-consciousness, emphasizing the bodily information channels that provide us the immediate certainty, in a first person perspective, that the self is bodily in a non-metaphorical sense.

Differential impacts of elevated CO2 and acidosis on the energy budget of gill and liver cells from Atlantic cod

Ocean acidification impacts fish and other marine species through increased seawater PCO2 levels (hypercapnia). Knowledge of the physiological mechanisms mediating effects in various tissues of fish is incomplete. Here we tested the effects of extracellular hypercapnia and acidosis on energy metabolism of gill and liver cells of Atlantic cod. Exposure media mimicked blood conditions in vivo, either during normo- or hypercapnia and at control or acidic extracellular pH (pHe). We determined metabolic rate and energy expenditure for protein biosynthesis, Na+/K+-ATPase and H+-ATPase and considered nutrition status by measurements of metabolic rate and protein biosynthesis in media with and without free amino acids (FAA). Addition of FAA stimulated hepatic but not branchial oxygen consumption. Normo- and hypercapnic acidosis as well as hypercapnia at control pHe depressed metabolic stimulation of hepatocytes. In gill cells, acidosis depressed respiration independent of PCO2 and FAA levels. For both cell types, depressed respiration was not correlated with the same reduction in energy allocated to protein biosynthesis or Na+/K+-ATPase. Hepatic energy expenditure for protein synthesis and Na+/K+- ATPase was even elevated at acidic compared to control pHe suggesting increased costs for ion regulation and cel- lular reorganization. Hypercapnia at control pHe strongly reduced oxygen demand of branchial Na+/K+-ATPase with a similar trend for H+-ATPase. We conclude that extracellular acidosis triggers metabolic depression in gill and metabolically stimulated liver cells. Additionally, hypercapnia itself seems to limit capacities for metabolic usage of amino acids in liver cells while it decreases the use and costs of ion regulatory ATPases in gill cells.

Hormonal changes related to paternal and alloparental care in common marmosets (Callithrix jacchus)

The physiological mechanisms of parental and alloparental care in cooperatively breeding nonhuman primate species such as the common marmoset (Callithrix jacchus) are poorly known. In this study, we examined prolactin and cortisol plasma levels of fathers and older offspring of both sexes, with and without previous experience in infant carrying, around parturition and during infant carrying. Blood samples were collected from fathers and older offspring and prolactin and cortisol were measured by RIA and EIA, respectively. Prolactin levels of both caretakers were not influenced by infant’s birth, previous experience or proximity to parturition. However, prolactin levels increased in both caretakers while in physical contact with infants and also with the number of infants being carried in older offspring. These findings suggest that increased prolactin seems to be mainly due to physical effort rather than a physiological trigger of paternal and alloparental care in common marmosets. Cortisol levels were higher for experienced fathers shortly before parturition which could act to reinforce affiliative bonds between breeding males and females at this time or in the ability of males to detect the proximity of the parturition or both

Intolérence à l'effort en hypertension artérielle pulmonaire : Implication des déterminants périphériques

L’hypertension artérielle pulmonaire (HTAP) est une maladie caractérisée par l’augmentation progressive des résistances vasculaires pulmonaires causant une augmentation de la pression artérielle pulmonaire qui mène au décès prématuré des patients. Malgré une amélioration rapide ces dernières années des traitements spécifiques, les patients souffrant d’HTAP demeurent dyspnéiques et intolérants à l’effort. L’atteinte vasculaire pulmonaire est actuellement irréversible. Elle est également la source de plusieurs anomalies au niveau des systèmes cardiovasculaires, ventilatoires et musculaires constituant les principaux déterminants physiologiques de la capacité à l’effort des patients. Cette thèse a investigué différentes facettes de la tolérance à l’effort en HTAP : les différents mécanismes ayant un impact sur l’apport musculaire en oxygène, l’altération des voies de signalisation cellulaire impliquées dans l’angiogenèse musculaire et les mécanismes ayant un impact sur la régulation du débit sanguin et l’oxygénation cérébrale en HTAP. Nous avons premièrement documenté une diminution de l’apport en oxygène aux muscles squelettiques à l’effort des patients en relation avec une diminution de la densité capillaire musculaire. Ce défaut d’angiogenèse corrélait d’ailleurs avec la capacité à l’effort des sujets. Par la suite, nous avons étudié les voies de signalisations cellulaires de l’angiogenèse musculaire. Ces résultats ont permis de démontrer une diminution de l’expression de miR-126, unique aux patients HTAP, qui était responsable de la diminution de la densité capillaire et qui contribuait à leur intolérance à l’effort. De plus, il était possible de moduler in vivo l’expression de miR-126. L’expérimentation in vivo, à l’aide d’un modèle murin d’HTAP, a permis de rétablir l’expression de miR-126, d’augmenter la microcirculation musculaire et d’améliorer la tolérance à l’effort des animaux, ce qui met en lumière le potentiel thérapeutique de l’angiogenèse musculaire pour améliorer la capacité à l’effort en HTAP. Notre dernier projet a démontré que les patients HTAP présentaient une diminution de débit sanguin cérébral. Ce projet a également démontré que les changements de pression artérielle sont moins bien amortis par les vaisseaux cérébraux des patients et que leurs vaisseaux cérébraux étaient moins réactifs aux changements de CO2. Les patients présentaient aussi une augmentation de la sensibilité des chémorécepteurs centraux qui contribuait à augmenter leur ventilation au repos, mais aussi à l’exercice. Finalement, à l’effort, nous avons démontré que le débit sanguin cérébral des patients HTAP était principalement influencé par la pression artérielle alors que chez les sujets sains, le débit sanguin cérébral était influencé principalement par la PETCO2. Nous avons également démontré que les patients HTAP présentaient une diminution progressive de leur oxygénation cérébrale, qui corrélait avec leur capacité à l’effort. Les résultats obtenus au cours de ce doctorat démontrent bien que la capacité à l’effort en HTAP est aussi déterminée par plusieurs anomalies physiopathologiques périphériques.

Hormonal changes related to paternal and alloparental care in common marmosets (Callithrix jacchus)

The physiological mechanisms of parental and alloparental care in cooperatively breeding nonhuman primate species such as the common marmoset (Callithrix jacchus) are poorly known. In this study, we examined prolactin and cortisol plasma levels of fathers and older offspring of both sexes, with and without previous experience in infant carrying, around parturition and during infant carrying. Blood samples were collected from fathers and older offspring and prolactin and cortisol were measured by RIA and EIA, respectively. Prolactin levels of both caretakers were not influenced by infant’s birth, previous experience or proximity to parturition. However, prolactin levels increased in both caretakers while in physical contact with infants and also with the number of infants being carried in older offspring. These findings suggest that increased prolactin seems to be mainly due to physical effort rather than a physiological trigger of paternal and alloparental care in common marmosets. Cortisol levels were higher for experienced fathers shortly before parturition which could act to reinforce affiliative bonds between breeding males and females at this time or in the ability of males to detect the proximity of the parturition or both

A aplicação de plasma rico em plaquetas na regeneração dos tecidos periodontais

O periodonto é uma unidade biológica e funcional, constituída pela gengiva, pelo cemento, pelo ligamento periodontal e pelo osso alveolar. O seu processo de cicatrização envolve mecanismos fisiológicos complexos que requerem a ação dos fatores de crescimento, péptidos oriundos da desgranulação das plaquetas. Neste sentido surge o Plasma Rico em Plaquetas como um produto autólogo, obtido a partir da centrifugação do sangue do próprio paciente e que visa melhorar a cicatrização dos tecidos após procedimentos enquadrados na Medicina Dentária. Esta revisão bibliográfica baseou-se numa pesquisa realizada na base de dados MEDLINE, via pubmed. Foram utilizadas as palavras-chave “plasma rich in growth factors”, “platelet-rich plasma”, “oral surgery”, “dental implants”, “sinus lift”, “third molar surgery” e “bone regeneration”. Após leitura de 40 artigos, foram descartados 9 pela sua pouca relevância no contexto. O objetivo é avaliar a efetividade da aplicação de plasma rico em plaquetas na regeneração dos tecidos periodontais em situações clínicas como alvéolos pós-extracionais, cirurgias de implantes, cirurgias de elevação do seio maxilar e na regeneração óssea. A efetividade em tecidos moles parece ser consensual. A efetividade no tecido ósseo é alvo de contradição entre os diversos autores, concluindo-se que há necessidade de mais estudos randomizados e controlados para que se possa responder à questão com evidência científica suficiente.

Neuromorphic model for sound source segregation

While humans can easily segregate and track a speaker's voice in a loud noisy environment, most modern speech recognition systems still perform poorly in loud background noise. The computational principles behind auditory source segregation in humans is not yet fully understood. In this dissertation, we develop a computational model for source segregation inspired by auditory processing in the brain. To support the key principles behind the computational model, we conduct a series of electro-encephalography experiments using both simple tone-based stimuli and more natural speech stimulus. Most source segregation algorithms utilize some form of prior information about the target speaker or use more than one simultaneous recording of the noisy speech mixtures. Other methods develop models on the noise characteristics. Source segregation of simultaneous speech mixtures with a single microphone recording and no knowledge of the target speaker is still a challenge. Using the principle of temporal coherence, we develop a novel computational model that exploits the difference in the temporal evolution of features that belong to different sources to perform unsupervised monaural source segregation. While using no prior information about the target speaker, this method can gracefully incorporate knowledge about the target speaker to further enhance the segregation.Through a series of EEG experiments we collect neurological evidence to support the principle behind the model. Aside from its unusual structure and computational innovations, the proposed model provides testable hypotheses of the physiological mechanisms of the remarkable perceptual ability of humans to segregate acoustic sources, and of its psychophysical manifestations in navigating complex sensory environments. Results from EEG experiments provide further insights into the assumptions behind the model and provide motivation for future single unit studies that can provide more direct evidence for the principle of temporal coherence.

Defensin-Like ZmES4 Mediates Pollen Tube Burst in Maize via Opening of the Potassium Channel KZM1

In contrast to animals and lower plant species, sperm cells of flowering plants are non-motile and are transported to the female gametes via the pollen tube, i.e. the male gametophyte. Upon arrival at the female gametophyte two sperm cells are discharged into the receptive synergid cell to execute double fertilization. The first players involved in inter-gametophyte signaling to attract pollen tubes and to arrest their growth have been recently identified. In contrast the physiological mechanisms leading to pollen tube burst and thus sperm discharge remained elusive. Here, we describe the role of polymorphic defensin-like cysteine-rich proteins ZmES1-4 (Zea mays embryo sac) from maize, leading to pollen tube growth arrest, burst, and explosive sperm release. ZmES1-4 genes are exclusively expressed in the cells of the female gametophyte. ZmES4-GFP fusion proteins accumulate in vesicles at the secretory zone of mature synergid cells and are released during the fertilization process. Using RNAi knock-down and synthetic ZmES4 proteins, we found that ZmES4 induces pollen tube burst in a species-preferential manner. Pollen tube plasma membrane depolarization, which occurs immediately after ZmES4 application, as well as channel blocker experiments point to a role of K(+)-influx in the pollen tube rupture mechanism. Finally, we discovered the intrinsic rectifying K(+) channel KZM1 as a direct target of ZmES4. Following ZmES4 application, KZM1 opens at physiological membrane potentials and closes after wash-out. In conclusion, we suggest that vesicles containing ZmES4 are released from the synergid cells upon male-female gametophyte signaling. Subsequent interaction between ZmES4 and KZM1 results in channel opening and K(+) influx. We further suggest that K(+) influx leads to water uptake and culminates in osmotic tube burst. The species-preferential activity of polymorphic ZmES4 indicates that the mechanism described represents a pre-zygotic hybridization barrier and may be a component of reproductive isolation in plants.

Patterns of sedentary behavior : insights from observational and experimental studies on body composition and energy expenditure

It is recognized that sedentary behavior (SB) has deleterious effects on numerous health outcomes and it appears that physiological mechanisms underlying these harms are distinct from the ones explaining moderate-to-vigorous physical activity (MVPA) benefits. Sedentary behavior represents a large portion of human’s life and is increasing with technological development. A new current of opinion supports the idea that the manner SB is accumulated plays an important role. This dissertation presents six research studies conducted under the scope of SB. In the methodological area, the first study highlighted the magnitude of potential errors in estimating SB and its patterns from common alternative methods (accelerometer and heart rate monitor) compared to ActivPAL. This study presented the accelerometer as a valid method at a group level. Two studies (2 and 5) were performed in older adults (the most sedentary group in the population) to test the associations for SB patterns with abdominal obesity using accelerometry. The findings showed positive graded associations for prolonged sedentary bouts with abdominal obesity and showed that those who interrupted SB more frequently were less likely to present abdominal obesity. Therefore, public health recommendations regarding breaking up SB more often are expected to be relevant. The associations between sedentary patterns and abdominal obesity were independent of MVPA in older adults. However, the low MVPA in this group makes it unclear whether this independent relationship still exists if highly active persons are analysed. Study 3 inovates by examining the association of SB with body fatness in highly trained athletes and found SB to predict total fat mass and trunk fat mass, independently of age and weekly training time. Study 4 also brings novelty to this research field by quantifying the metabolic and energetic cost of the transition from sitting to standing and then sitting back down (a break), informing about the modest energetic costs (0.32 kcal·min−1). Finally, from a successful multicomponent pilot intervention to reduce and break up SB (study 6), an important behavioral resistance to make more sit/stand transitions despite successfully reducing sitting time (~ 1.85 hours·day-1) was found, which may be relevant to inform future behavioral modification programs. The present work provides observational and experimental evidence on the relation for SB patterns with body composition outcomes and energy regulation that may be relevant for public health interventions.

The transition from health to sickness via the chloroplast

Microbe associated molecular pattern (MAMP) receptors in plants recognize MAMPs and activate basal defences; however a complete understanding of the molecular and physiological mechanisms conferring immunity remains elusive. Pathogens suppress active defence in plants through the combined action of effector proteins. This talk presents results showing the chloroplast as a key component of early immune responses. MAMP perception triggers the rapid, large-scale suppression of nuclear encoded chloroplast-targeted genes (NECGs). Virulent Pseudomonas syringae effectors reprogramme NECG expression in Arabidopsis, target the chloroplast and inhibit photosynthetic CO2 assimilation through disruption of photosystem II. This activity prevents a chloroplastic reactive oxygen burst. These physiological changes precede bacterial multiplication and coincide with pathogen-induced abscisic acid (ABA) accumulation. MAMP pretreatment protects chloroplasts from effector manipulation, whereas application of ABA or the inhibitor of photosynthetic electron transport, DCMU, abolishes the MAMP-induced chloroplastic reactive oxygen burst, and enhances growth of a P. syringae hrpA mutant that fails to secrete effectors.

Exploring the relationship between patterns of physical activity, sedentary behaviour and cardiometabolic health in middle-aged Irish adults

Background and Study Rationale Being physically active is a major contributor to both physical and mental health. More specifically, being physically active lowers risk of coronary heart disease, high blood pressure, stroke, metabolic syndrome (MetS), diabetes, certain cancers and depression, and increases cognitive function and wellbeing. The physiological mechanisms that occur in response to physical activity and the impact of total physical activity and sedentary behaviour on cardiometabolic health have been extensively studied. In contrast, limited data evaluating the specific effects of daily and weekly patterns of physical behaviour on cardiometabolic health exist. Additionally, no other study has examined interrelated patterns and minute-by-minute accumulation of physical behaviour throughout the day across week days in middle-aged adults. Study Aims The overarching aims of this thesis are firstly to describe patterns of behaviour throughout the day and week, and secondly to explore associations between these patterns and cardiometabolic health in a middle-aged population. The specific objectives are to: 1 Compare agreement between the International Physical Activity Questionnaire-Short Form (IPAQ-SF) and GENEActiv accelerometer-derived moderate-to-vigorous (MVPA) activity and secondly to compare their associations with a range of cardiometabolic and inflammatory markers in middle-aged adults. 2 Determine a suitable monitoring frame needed to reliably capture weekly, accelerometer-measured, activity in our population. 3 Identify groups of participants who have similar weekly patterns of physical behaviour, and determine if underlying patterns of cardiometabolic profiles exist among these groups. 4 Explore the variation of physical behaviour throughout the day to identify whether daily patterns of physical behaviour vary by cardiometabolic health. Methods All results in this thesis are based on data from a subsample of the Mitchelstown Cohort; 475 (46.1% males; mean aged 59.7±5.5 years) middle-aged Irish adults. Subjective physical activity levels were assessed using the IPAQ-SF. Participants wore the wrist GENEActiv accelerometer for 7 consecutive days. Data was collected at 100Hz and summarised into a signal magnitude vector using 60s epochs. Each time interval was categorised based on validated cut-offs. Data on cardiometabolic and inflammatory markers was collected according to standard protocol. Cardiometabolic outcomes (obesity, diabetes, hypertension and MetS) were defined according to internationally recognised definitions by World Health Organisation (WHO) and Irish Diabetes Federation (IDF). Results The results of the first chapter suggest that the IPAQ-SF lacks the sensitivity to assess patterning of activity and guideline adherence and assessing the relationship with cardiometabolic and inflammatory markers. Furthermore, GENEActiv accelerometer-derived MVPA appears to be better at detecting relationships with cardiometabolic and inflammatory markers. The second chapter examined variations in day-to-day physical behaviour levels between- and within-subjects. The main findings were that Sunday differed from all other days in the week for sedentary behaviour and light activity and that a large within-subject variation across days of the week for vigorous activity exists. Our data indicate that six days of monitoring, four weekdays plus Saturday and Sunday, are required to reliably estimate weekly habitual activity in all activity intensities. In the next chapter, latent profile analysis of weekly, interrelated patterns of physical behaviour identified four distinct physical behaviour patterns; Sedentary Group (15.9%), Sedentary; Lower Activity Group (28%), Sedentary; Higher Activity Group (44.2%) and a Physically Active Group (11.9%). Overall the Sedentary Group had poorer outcomes, characterised by unfavourable cardiometabolic and inflammatory profiles. The remaining classes were characterised by healthier cardiometabolic profiles with lower sedentary behaviour levels. The final chapter, which aimed to compare daily cumulative patterns of minute-by-minute physical behaviour intensities across those with and without MetS, revealed significant differences in weekday and weekend day MVPA. In particular, those with MetS start accumulating MVPA later in the day and for a shorted day period. Conclusion In conclusion, the results of this thesis add to the evidence base regards an optimal monitoring period for physical behaviour measurement to accurately capture weekly physical behaviour patterns. In addition, the results highlight whether weekly and daily distribution of activity is associated with cardiometabolic health and inflammatory profiles. The key findings of this thesis demonstrate the importance of daily and weekly physical behaviour patterning of activity intensity in the context of cardiometabolic health risk. In addition, these findings highlight the importance of using physical behaviour patterns of free-living adults observed in a population-based study to inform and aid health promotion activity programmes and primary care prevention and treatment strategies and development of future tailored physical activity based interventions.

Effects and Modes od Action of Canopy Management Practices on Vine Physiology and Berry Composition in Organically-Cultivated cv. Sangiovese (Vitis Vinifera L.)

In organic and biodynamic vineyards, canopy management practices should be carefully and timely modulated, particularly in a context of climate change, for successfully achieving balanced plants, ventilated and exposed berries, elevated grape and wine quality. In 2013 and 2014, characterized by contrasting climatic conditions, the implications of post-veraison (late) or pea-size trimming, post-veraison or pre-harvest late defoliations and shoot-positioning (post-veraison) were assessed against long-shoots non treated controls, under field conditions on organically-cultivated cv. Sangiovese. The key agronomic and enological relevance of late trimming and defoliations clearly emerged in both seasons. Berry skin phenolics (e.g. anthocyanins, flavonols) increased markedly, without changes in technological parameters. In case of early trimming, such positive effects were observed only in 2013. Maintaining long shoots for shading decreased anthocyanins, flavonols and total phenolics concentrations and promoted the production of compact bunches. Experimental data strongly designated late trimming, a practice proved to contain yield and bunch compactness, as a valuable alternative to cluster thinning. Late trimming, defoliations and shoot positioning reduced the severity of Botrytis cluster rot. The highest levels of berry skins phenolic compounds in late trimmed and defoliated plants could have contributed control the severity of this pathogen. The enological benefits induced by late trimming and defoliations and shoot positioning emerged in both young and aged wines. For the first time, cell cultures from cv. Sangiovese berry tissues were obtained and enabled to investigate, in controlled conditions, the relations between mechanisms regulating secondary metabolism in grapevine cells and changes induced by environmental and agronomic factors. The Doctoral Dissertation strongly highlights the need to consider, for a proper interpretation of the multiple modifications induced by canopy management strategies, physiological mechanisms other than the canonic source-sink relationships, in particular their impact on the vine hormonal status.

Transcriptome analysis of neutrophils after endurance exercise reveals novel signaling mechanisms in the immune response to physiological stress

Neutrophils serve as an intriguing model for the study of innate immune cellular activity induced by physiological stress. We measured changes in the transcriptome of circulating neutrophils following an experimental exercise trial (EXTRI) consisting of 1 h of intense cycling immediately followed by 1 h of intense running. Blood samples were taken at baseline, 3 h, 48 h, and 96 h post-EXTRI from eight healthy, endurance-trained, male subjects. RNA was extracted from isolated neutrophils. Differential gene expression was evaluated using Illumina microarrays and validated with quantitative PCR. Gene set enrichment analysis identified enriched molecular signatures chosen from the Molecular Signatures Database. Blood concentrations of muscle damage indexes, neutrophils, interleukin (IL)-6 and IL-10 were increased (P < 0.05) 3 h post-EXTRI. Upregulated groups of functionally related genes 3 h post-EXTRI included gene sets associated with the recognition of tissue damage, the IL-1 receptor, and Toll-like receptor (TLR) pathways (familywise error rate, P value < 0.05). The core enrichment for these pathways included TLRs, low-affinity immunoglobulin receptors, S100 calcium binding protein A12, and negative regulators of innate immunity, e.g., IL-1 receptor antagonist, and IL-1 receptor associated kinase-3. Plasma myoglobin changes correlated with neutrophil TLR4 gene expression (r = 0.74; P < 0.05). Neutrophils had returned to their nonactivated state 48 h post-EXTRI, indicating that their initial proinflammatory response was transient and rapidly counterregulated. This study provides novel insight into the signaling mechanisms underlying the neutrophil responses to endurance exercise, suggesting that their transcriptional activity was particularly induced by damage-associated molecule patterns, hypothetically originating from the leakage of muscle components into the circulation.

Differential Mechanisms of Binding of Anti-Sigma Factors Escherichia coli Rsd and Bacteriophage T4 AsiA to E. coli RNA Polymerase Lead to Diverse Physiological Consequences

Anti-sigma factors Escherichia coli Rsd and bacteriophage T4 AsiA bind to the essential housekeeping sigma factor, sigma(70), of E. coli. Though both factors are known to interact with the C-terminal region of sigma(70), the physiological consequences of these interactions are very different. This study was undertaken for the purpose of deciphering the mechanisms by which E. coli Rsd and bacteriophage T4 AsiA inhibit or modulate the activity of E. coli RNA polymerase, which leads to the inhibition of E. coli cell growth to different amounts. It was found that AsiA is the more potent inhibitor of in vivo transcription and thus causes higher inhibition of E. coli cell growth. Measurements of affinity constants by surface plasmon resonance experiments showed that Rsd and AsiA bind to or 70 with similar affinity. Data obtained from in vivo and in vitro binding experiments clearly demonstrated that the major difference between AsiA and Rsd is the ability of AsiA to form a stable ternary complex with RNA polymerase. The binding patterns of AsiA and Rsd with sigma(70) studied by using the yeast two-hybrid system revealed that region 4 of sigma(70) is involved in binding to both of these anti-sigma factors; however, Rsd interacts with other regions of sigma(70) as well. Taken together, these results suggest that the higher inhibition of E. coli growth by AsiA expression is probably due to the ability of the AsiA protein to trap the holoenzyme RNA polymerase rather than its higher binding affinity to sigma(70).