993 resultados para pi Ring interaction


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Reciprocal selection between interacting species is a major driver of biodiversity at both the genetic and the species level. This reciprocal selection, or coevolution, has led to the diversification of two highly diverse and abundant groups of organisms, flowering plants and their insect herbivores. In heterogeneous environments, the outcome of coevolved species interactions is influenced by the surrounding community and/or the abiotic environment. The process of adaptation allows species to adapt to their local conditions and to local populations of interacting species. However, adaptation can be disrupted or slowed down by an absence of genetic variation or by increased inbreeding, together with the following inbreeding depression, both of which are common in small and isolated populations that occur in fragmented environments. I studied the interaction between a long-lived plant Vincetoxicum hirundinaria and its specialist herbivore Abrostola asclepiadis in the southwestern archipelago of Finland. I focused on mutual local adaptation of plants and herbivores, which is a demonstration of reciprocal selection between species, a prerequisite for coevolution. I then proceeded to investigate the processes that could potentially hamper local adaptation, or species interaction in general, when the population size is small. I did this by examining how inbreeding of both plants and herbivores affects traits that are important for interaction, as well as among-population variation in the effects of inbreeding. In addition to bi-parental inbreeding, in plants inbreeding can arise from self-fertilization which has important implications for mating system evolution. I found that local adaptation of the plant to its herbivores varied among populations. Local adaptation of the herbivore varied among populations and years, being weaker in populations that were most connected. Inbreeding caused inbreeding depression in both plants and herbivores. In some populations inbreeding depression in herbivore biomass was stronger in herbivores feeding on inbred plants than in those feeding on outbred ones. For plants it was the other way around: inbreeding depression in anti-herbivore resistance decreased when the herbivores were inbred. Underlying some of the among-population variation in the effects of inbreeding is variation in plant phenolic compounds. However, variation in the modification of phenolic compounds in the digestive tract of the herbivore did not explain the inbreeding depression in herbivore biomass. Finally, adult herbivores had a preference for outbred host plants for egg deposition, and herbivore inbreeding had a positive effect on egg survival when the eggs were exposed to predators and parasitoids. These results suggest that plants and herbivores indeed exert reciprocal selection, as demonstrated by the significant local adaptation of V. hirundinaria and A. asclepiadis to one another. The most significant cause of disruption of the local adaptation of herbivore populations was population connectivity, and thus probably gene flow. In plants local adaptation tended to increase with increasing genetic variation. Whether or not inbreeding depression occurred varied according to the life-history stage of the herbivore and/or the plant trait in question. In addition, the effects of inbreeding strongly depended on the population. Taken together, inbreeding modified plant-herbivore interactions at several different levels, and can thus affect the strength of reciprocal selection between species. Thus inbreeding has the potential to affect the outcome of coevolution.

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Almost identical polyglutamine-containing proteins with unknown structures have been found in human, mouse and rat genomes (GenBank AJ277365, AF525300, AY879229). We infer that an identical new gene (RING) finger domain of real interest is located in each C-terminal segment. A three-dimensional (3-D) model was generated by remote homology modeling and the functional implications are discussed. The model consists of 65 residues from terminal position 707 to 772 of the human protein with a total length of 796 residues. The 3-D model predicts a ubiquitin-protein ligase (E3) as a binding site for ubiquitin-conjugating enzyme (E2). Both enzymes are part of the ubiquitin pathway to label unwanted proteins for subsequent enzymatic degradation. The molecular contact specificities are suggested for both the substrate recognition and the residues at the possible E2-binding surface. The predicted structure, of a ubiquitin-protein ligase (E3, enzyme class number 6.3.2.19, CATH code 3.30.40.10.4) may contribute to explain the process of ubiquitination. The 3-D model supports the idea of a C3HC4-RING finger with a partially new pattern. The putative E2-binding site is formed by a shallow hydrophobic groove on the surface adjacent to the helix and one zinc finger (L722, C739, P740, P741, R744). Solvent-exposed hydrophobic amino acids lie around both zinc fingers (I717, L722, F738, or P765, L766, V767, V733, P734). The 3-D structure was deposited in the protein databank theoretical model repository (2B9G, RCSB Protein Data Bank, NJ).

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Type 2 diabetes mellitus is a systemic disease characterized by intolerance to glucose and peripheral resistance to insulin. This endocrine disease affects fundamental mechanisms of the central nervous system and jeopardizes the balance of vital functions such as the cardiovascular and circadian rhythm. The increased prevalence of metabolic disorders in our society is aggravated by endemic voluntary postponement of bedtime and by the current sedentary lifestyle, leading to epidemic proportions of obese people. Diabetes and chronic loss of sleep share the fact that both affect millions and one is detrimental to the other. Indeed, sleep deficits have marked modulatory effects on glucose metabolism and insulin sensitivity and foster metabolic syndrome that culminates in sleep disorders like restless syndrome and sleep apnea, which in turn lead to poor sleep quality. We examine the hypothesis that these two worldwide emerging disorders are due to two interlinked cycles. In our paradigm, we establish an intimate relationship between diabetes and sleep disturbances and postulate possible mechanisms that provide support for this conjecture. In addition, we propose some perspectives about the development of the reciprocal interaction between predictor components of metabolic syndrome and sleep disturbances that lead to poor sleep quality. The ability to predict the development and identify or associate a given mode of sleep disturbance to diabetes would be a valuable asset in the assessment of both. Furthermore, major advances in care coupled with healthy lifestyles can ensure a higher quality of life for people with diabetes.

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Efonidipine hydrochloride is an antihypertensive and antianginal agent with fewer side effects and is better tolerated in the treatment of hypertension with renal impairment. Its interaction with bovine serum albumin (BSA) is of great use for the understanding of the pharmacokinetic and pharmacodynamic mechanisms of the drug. The binding of efonidipine to BSA was investigated by fluorescence spectroscopy and circular dichroism. BSA fluorescence was quenched by efonidipine, due to the fact that efonidipine quenched the fluorescence of tryptophan residues mainly by the collision mode. The thermodynamic parameters ΔH0 and ΔS0 were 68.04 kJ/mol and 319.42 J·mol-1·K-1, respectively, indicating that the hydrophobic interactions played a major role. The results of circular dichroism and synchronous fluorescence measurements showed that the binding of efonidipine to BSA led to a conformational change of BSA. The fraction of occupied sites (θ) for the 8-anilino-1-naphthalein-sulfonic acid (ANS)-BSA system is 85%, whereas for the NZ-105-BSA system, it is 53%, which suggests that the interaction of ANS with BSA is stronger than that of NZ-105 with BSA. Binding studies in the presence of ANS indicated that efonidipine competed with ANS for hydrophobic sites of BSA. The effects of metal ions on the binding constant of the efonidipine-BSA complex were also investigated. The presence of metal ions Zn2+, Mg2+, Al3+, K+, and Ca2+ increased the binding constant of efonidipine_BSA complex, which may prolong the storage period of NZ-105 in blood plasma and enhance its maximum effects.

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Estrogen has multiple effects on lipid and lipoprotein metabolism. We investigated the association between the four common single nucleotide polymorphisms in the estrogen receptor 1 (ESR1) gene locus, -1989T>G, +261G>C, IVS1-397T>C and IVS1-351A>G, and lipid and lipoprotein levels in southern Brazilians. The sample consisted in 150 men and 187 premenopausal women. The women were considered premenopausal if they had regular menstrual bleeding within the previous 3 months and were 18-50 years of age. Exclusion criteria were pregnancy, secondary hyperlipidemia due to renal, hepatic or thyroid disease, and diabetes. Smoking status was self-reported; subjects were classified as never smoked and current smokers. DNA was amplified by PCR and was subsequently digested with the appropriate restriction enzymes. Statistical analysis was carried out for men and women separately. In the study population, major allele frequencies were _1989*T (0.83), +261*G (0.96), IVS1-397*T (0.58), and IVS1-351*A (0.65). Multiple linear regression analyses indicated that an interaction between +261G>C polymorphism and smoking was a significant factor affecting high-density lipoprotein cholesterol (HDL-C) levels (P = 0.028) in women. Nonsmoking women with genotype G/C of +261G>C polymorphism had mean HDL-C levels higher than those with G/G genotype (1.40 ± 0.33 vs 1.22 ± 0.26 mmol/L; P = 0.033). No significant associations with lipid and lipoprotein levels in women and men were detected for other polymorphisms. In conclusion, the +261G>C polymorphism might influence lipoprotein and lipid levels in premenopausal women, but these effects seem to be modulated by smoking, whereas in men ESR1 polymorphisms were not associated with high lipoprotein levels.

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The objective of this study was to determine the effects of GDF-9, IGF-I, and GH alone or combined on preantral follicle survival, activation and development after 1 and 7 days of in vitro culture. Either fresh (non-cultured) or cultured ovarian tissue was processed for histological and fluorescence analysis. For all media tested, the percent of normal follicles was greater when compared to minimum essential medium supplemented (MEM+) alone, except when ovarian tissue was cultured with GDF-9/IGF-I or GDF-9/GH (P < 0.05). Fluorescence analysis showed that the percent of viable follicles after 7 days of culture was similar for non-cultured tissue and for all treatments tested. The percent of primordial follicles was reduced (P < 0.05) and there was a significant and concomitant increase in the percent of intermediate and primary follicles in all treatments tested after 7 days of culture when compared to non-cultured tissue. After 7 days of culture, the highest percent of intermediate follicles was observed with IGF-I/GH (61.3%), and the highest percent of primary follicles was achieved with IGF-I (57.7%). After 7 days of culture in MEM+ containing GDF-9, IGF-I and GH alone or in all associations, a significant increase in follicular diameter was observed when compared to MEM+ alone and non-cultured tissue. In conclusion, GDF-9, IGF-I and GH alone or in combination maintain preantral follicle survival and promote primordial follicle activation. Nevertheless, the data showed that IGF-I/GH and IGF-I alone are efficient in promoting the transition from primordial to intermediate follicles and from intermediate to primary follicles, respectively.

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Interplay between the host and human cytomegalovirus (HCMV) has a pivotal role in the outcome of infection. A region (referred to as UL/b’) present in the Toledo strain of HCMV and low passage clinical isolates contains 19 additional genes, which are absent in the highly passaged laboratory strain AD169. Products of the UL/b’ genes may determine the manifestations of HCMV infection in vivo. However, little is known about the host factors, which interact with UL/b’ proteins. This study was conducted to investigate the function of the HCMV UL136 protein. By yeast two-hybrid screening, the β1 subunit of the host Na+/K+-ATPase (ATP1B1) was identified to be a candidate protein, which interacts with the HCMV UL136 protein. The interaction was further evaluated both in vitro by pull-down assay and in vivo by immunofluorescent co-localization. The results showed that the UL136 protein can interact with ATP1B1 in vitro. Co-localization of UL136-EGFP and ATP1B1-DsRed in cell membranes suggests that ATP1B1 was a partner of the UL136 protein. It can be proposed that the HCMV UL136 protein may have important roles in processes such as cell-to-cell spread, and in maintaining cell osmotic pressure and intracellular ion homeostasis during HCMV infection.

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Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the N-truncated protein in response to fixed nitrogen levels. We also used pull-down assays to show in vitro interaction between the purified N-terminal GAF domain of NifA and the GlnB protein. The results showed that A. brasilense GlnB interacts directly with the NifA N-terminal domain and this interaction is dependent on the presence of ATP and 2-oxoglutarate.

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The visualization of tools and manipulable objects activates motor-related areas in the cortex, facilitating possible actions toward them. This pattern of activity may underlie the phenomenon of object affordance. Some cortical motor neurons are also covertly activated during the recognition of body parts such as hands. One hypothesis is that different subpopulations of motor neurons in the frontal cortex are activated in each motor program; for example, canonical neurons in the premotor cortex are responsible for the affordance of visual objects, while mirror neurons support motor imagery triggered during handedness recognition. However, the question remains whether these subpopulations work independently. This hypothesis can be tested with a manual reaction time (MRT) task with a priming paradigm to evaluate whether the view of a manipulable object interferes with the motor imagery of the subject's hand. The MRT provides a measure of the course of information processing in the brain and allows indirect evaluation of cognitive processes. Our results suggest that canonical and mirror neurons work together to create a motor plan involving hand movements to facilitate successful object manipulation.

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The aim of this study was to explore the clinical efficacy of a novel retrograde puncture approach to establish a preperitoneal space for laparoscopic direct inguinal hernia repair with inguinal ring suturing. Forty-two patients who underwent laparoscopic inguinal hernia repair with retrograde puncture for preperitoneal space establishment as well as inguinal ring suturing between August 2013 and March 2014 at our hospital were enrolled. Preperitoneal space was successfully established in all patients, with a mean establishment time of 6 min. Laparoscopic repairs were successful in all patients, with a mean surgical time of 26±15.1 min. Mean postoperative hospitalization duration was 3.0±0.7 days. Two patients suffered from postoperative local hematomas, which were relieved after puncturing and drainage. Four patients had short-term local pain. There were no cases of chronic pain. Patients were followed up for 6 months to 1 year, and no recurrence was observed. Our results demonstrate that preperitoneal space established by the retrograde puncture technique can be successfully used in adult laparoscopic hernioplasty to avoid intraoperative mesh fixation, and thus reduce medical costs.

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This study reviews the research on interaction techniques and methods that could be applied in mobile augmented reality scenarios. The review is focused on themost recent advances and considers especially the use of head-mounted displays. Inthe review process, we have followed a systematic approach, which makes the reviewtransparent, repeatable, and less prone to human errors than if it was conducted in amore traditional manner. The main research subjects covered in the review are headorientation and gaze-tracking, gestures and body part-tracking, and multimodality– as far as the subjects are related to human-computer interaction. Besides these,also a number of other areas of interest will be discussed.

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Tässä työssä esitetään venäläisen matemaatikon A.I. Shirshovin teorioita ja tuloksia sanojen kombinatoriikasta. Lisäksi näytetään miten ne soveltuvat PI-algebrojen maailmaan. Shirshovin tuloksia tarkasteltaessa käsitellään sanoja erillisinä kombinatorisina objekteina ja todistetaan Shirshovin Lemma, joka on tämän työn perusta. Lemmanmukaan tarpeeksi pitkille sanoille saadaan tiettyä säännönmukaisuutta ja se todistetaan kolme kertaa. Ensimmäisestä saadaan tarpeeksi pitkän sanan olemassaolo.Toinen todistus mukailee Shirshovin alkuperäistä todistusta. Kolmannessa todistuksessa annetaan tarpeeksi pitkälle sanalle paremmin käytäntöön soveltuva raja. Tämän jälkeen käsitellään sanoja algebrallisina objekteina. Työn päätuloksena todistetaan Shirshovin Korkeuslause, jonka mukaan jokainen äärellisesti generoidunPI-algebran alkio on sanojen ω1k1 ···ωdkd lineaarikombinaatio, missä sanojen ωi pi-tuudet sekä indeksi i ovat rajatut. Shirshovin Korkeuslauseesta seuraa suoraan positiivinen ratkaisu Kurochin ongelmaan PI-algebroilla sekä saadaan raja alkioiden lukumäärälle, jolla algebra generoituu moduliksi. Lisäksi esitetään toisena sovelluksena ilman todistuksia Shirshovin soveltuvuus Jacobsonin radikaalin nilpotenttisuuteen. Pääsääntöisenä lähteenä käytetään A. Kanel-Belowin ja L. H. Rowenin kirjaa: Computational aspects of polynomial identities.

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Tutkimuksessani tarkastelen myöhäiskeskiaikaisen maailmanhistoriateoksen, Ranulph Higdenin Polychroniconin, materiaalisia ilmentymiä. Vertailuun valittiin kaksi käsikirjoitusta, jotka sisältävät John Trevisan keskienglanninkielisen käännöksen kyseisestä teoksesta. Tutkielman lähtökohtana on ajatus, jonka mukaan käsikirjoitusten ja painettujen kirjojen välisistä eroista huolimatta myös ensin mainittuja voidaan tutkia kirjoina eli lukijan kohtaamina fyysisinä esineinä, jotka sisältävät varsinaisen tekstin lisäksi tekstuaalisia ja visuaalisia elementtejä, joilla tekstiä jäsennellään ja esitellään lukijalle ja jotka vaikuttavat lukijan lukukokemukseen ja ohjaavat lukuprosessia. Näiden elementtien kuvaamiseen ja analysointiin olen soveltanut Gérard Genetten parateksti-käsitettä, jonka käyttö käsikirjoitusten tutkimuksessa on toistaiseksi ollut vähäistä. Tutkielman tavoitteena on historiallisen pragmatiikan mukaisesti ottaa huomioon tekstien fyysinen ja sosiaalinen konteksti. Näkökulma painottuu vuorovaikutukseen kirjan tuottajien ja sen lukijoiden välillä, ja tutkielman tarkoitus on paitsi selvittää, millaisia elementtejä käsikirjoituksista löytyy lukijan lukuprosessia ohjaamaan ja tukemaan, myös tarkastella lukijoiden itsensä tekemiä merkintöjä. Tutkimustulokset osoittavat, että lukijoiden merkinnät noudattelivat osin samoja muotoja ja käyttötarkoituksia kuin kirjurien valmiiksi täydentämät elementit (esim. glossat) käsikirjoituksissa, mutta joitakin elementtejä täydennettiin mahdollisesti myös painettujen kirjojen myötä yleistyneiden käytäntöjen pohjalta. Analyysissani tarkastelen lähemmin myös teokseen liitettyjä esipuheita ja muita tekstejä tarkoituksenani selvittää, mitkä niistä voidaan luokitella parateksteiksi ja mikä merkitys niillä on kokonaisuuden kannalta. Tutkimuksessa kävi ilmi, että tekijän ja kääntäjän esipuheista löytyivät kaikki Genetten määrittämät kriteerit, kun taas aineiston toiseen käsikirjoitukseen sisältyvät muiden kirjoittajien tekstit eivät ole luokiteltavissa parateksteiksi, vaikka ne ulkoisesti sellaisilta vaikuttavat ja vaikka niistä on tullut paratekstien kaltainen kiinteä osa Polychroniconia.