Assessment of physiological potential of cucumber seeds using the software Seedling Vigor Imaging System® (SVIS®)

The software Seed Vigor Imaging System (SVIS®), has been successfully used to evaluate seed physiological potential by automated analyses of scanned seedlings. In this research, the efficiency of this system was compared to other tests accepted for assessing cucumber (Cucumis sativus L.) seed vigor of distinct seed lots of Supremo and Safira cultivars. Seeds were subjected to germination, traditional and saturated salt accelerated aging, seedling emergence, seedling length and SVIS analyses (determination of vigor indices and seedling growth uniformity, lengths of primary root, hypocotyl and whole seedlings). It was also determined whether the definition of seedling growth/uniformity ratios affects the sensitivity of the SVIS®. Results showed that analyses SVIS have provided consistent identification of seed lots performance, and have produced information comparable to those from recommended seed vigor tests, thus demonstrating a suitable sensitivity for a rapid and objective evaluation of physiological potential of cucumber seeds. Analyses of four-days-old cucumber seedlings using the SVIS® are more accurate and growth/uniformity does not affect the precision of results.

Physiological quality, content and activity of antioxidants in soybean seeds artificially aged

The objective of this study was to evaluate physiological quality, content, and activity of antioxidants, in soybean seeds subjected to accelerated aging during different periods. Seeds of cultivars BRS 258, BRS 262 and BRS 268, subjected to accelerated aging during 12, 24, 36 and 48 hours and non-aged seeds were used. After each aging period, the seed were evaluated by tests of: germination; first count and tetrazolium. The total of phenolic compounds, total flavonoides, total of isoflavones, and activity for eliminating ABTS●+ radicals were quantified. There were differences among cultivars according to vigor and viability only after seeds were aged. Cultivars BRS 158 and BRS 268 have shown better seed physiological quality in each aging period; however, not presenting higher amounts of isoflavones and efficiency in removing free radicals. For all cultivars, the values for total of phenolic compounds, as well as total of flavonoids have shown quadratic positive behavior; the values for isoflavones remained constant and the vigor and viability showed contrary trend to activity of antioxidant agents.

Physiological quality of coffee seeds produced under different levels of solar radiation and maturation stages

In Brazil, although the coffee plantations are predominantly grown under full sunlight, the use of agroforestry systems can lead to socioeconomic advantages, thus providing a favorable environment to the crop by promoting its sustainability as well as environmental preservation. However, there is a lack of information on physiological quality of the coffee seeds produced under different levels of solar radiation. Within this context, the objective of this study was to evaluate the influence of different levels of solar radiation and maturation stages on the physiological quality of coffee (Coffea arabica L.) seeds, cv. Acaiá Cerrado MG-1474. Three levels of solar radiation (plants grown under full sunlight; under plastic screens of 35% shading; and under plastic screens of 50% shading) and three maturation stages (cherry, greenish-yellow and green) were assessed. Physiological quality of seeds was assessed by using germination test, first count of germination, abnormal seedlings, dead seeds, and seedlings with open cotyledonary leaves. Electrophoretic analysis of isoenzymes catalase, esterase, superoxide dismutase and peroxidase was also performed. With the evolution of development the coffee seeds presents increases on physiological quality, and at its beginning the seeds show improvements on quality with the reduction of solar radiation.

Physiological potential of Brachiaria brizantha cv. Marandu seeds kept in contact with phosphatic fertilizers

The effect of mixture of seeds of Brachiaria brizantha, cv. Marandu, with different sources, granulometry, and phosphatic fertilizer doses during various periods of exposure on the physiological potential of the seeds has been assessed. The treatments consisted in seed exposure during periods of 0, 3, 6, 12, 24, 36, 48, 72, 96, and 120 h to the following fertilizers: ground granulated single superphosphate (SS), and powdered (SSp); and ground granulated ammonium monophosphate (AMP), at doses of 40 and 80 kg P2O5 ha-1. Tests of germination, tetrazolium, moisture content, and vigor (first count, electrical conductivity, emergence, emergence speed, and fresh mass of seedlings) were performed. It has been concluded that seed physiological potential of B. brizantha cv. Marandu is reduced with increase on the exposure period to phosphatic fertilizer. Such effect, however, is dependent on the product source, granulometry, and dose. SSp was the most harmful to seeds, followed by SSp and AMP, respectively. Moreover, considering a 60% germination rate as acceptable, it may be inferred that seeds can be kept in contact with AMP and SSp, in dose of 80 kg of P2O5 ha-1, respectively, for periods of 71.2 and 16.2 hours.

Physiological maturity of eggplant seeds

Determination of seed physiological maturity and ideal moment for harvesting fruits to extract their seeds are important aspects to produce seeds with high quality. To identify the best period for harvesting eggplant fruits, associated with ideal resting period of the fruit for extracting seeds, an eggplant production field was installed in municipality of Ijaci, in the State of Minas Gerais, Southwestern Brazil. The fruits were harvested at periods of 49, 56, 63, 70, and 77 days after pollination (DAP). The seeds of fruits harvested in each period were manually extracted immediately after harvest or after a post-harvest resting period of seven days, under a shed. The physiological quality of seeds was assessed by tests of: germination percentage; germination and emergence speed indexes; and electrical conductivity; which were carried out in the Central Seed Laboratory, Federal University of Lavras. Electrophoretic analyses of isoenzymes: catalase (CAT); esterase (EST); superoxide dismutase (SOD); and peroxidase (PO), were also therein performed. Results of germination and vigor of seeds have showed that the best period for harvesting the fruit is around 70 DAP; and that seeds should be extracted immediately after harvest. Electrophoretic analysis of enzymes has showed immaturity for eggplant seeds, harvested after 49 DAP.

Physiological potential of rice seeds treated with rhizobacteria or the insecticide thiamethoxam

Development of new technologies, aiming at increasing productivity in different crops, involves constant research on the effectiveness and application of these techniques in seed treatment. In this study, it was aimed at evaluating physiological potential of rice seeds treated with plant growth-promoting rhizobacteria (PGPR) (strains DFs185, DFs223, DFs306, DFs416), or with two dosages of the insecticide thiamethoxam. The variables assessed were: germination (G); first count of germination (FCG); cold test (CT); length of seedlings aerial parts (LAP), root system (LRS), and total length (TL); emergence speed index (ESI); emergence (E), at 14 days; and dry phytomass (DP). Treatments have had a positive effect on percentage of G, FCG and E. The strain DFs185 has promoted increase in percentage emergence, for five of the six lots assessed. The variables: LAP; LRS; TL; ESI; and DP have undergone low or none influence of treatments; and there has been no toxic effect of rhizobacteria or insecticide thiamethoxam. In the cold test, a negative effect of treatments has been detected. Seed treatment with rhizobacteria, as well as with thiamethoxam, improve quality of low quality rice seeds. The strain DFs185 is promising for treating rice seeds, once it stimulates seed germination and emergence.

Computerized imaging analysis of seedlings for assessment of physiological potential of wheat seeds

Nowadays, image analysis is one of the most modern tools in evaluating physiological potential of seeds. This study aimed at verifying the efficiency of the seedling imaging analysis to assess physiological potential of wheat seeds. The seeds of wheat, cultivars IAC 370 and IAC 380, each of which represented by five different lots, were stored during four months under natural environmental conditions of temperature (T) and relative humidity (RH), in municipality of Piracicaba, Stated of São Paulo, Brazil. For this, bimonthly assessments were performed to quantify moisture content and physiological potential of seeds by means of tests of: germination, first count, accelerated aging, electrical conductivity, seedling emergence, and computerized analysis of seedlings, using the Seed Vigor Imaging System (SVIS®). It has been concluded that the computerized analyses of seedling through growth indexes and vigor, using the SVIS®, is efficient to assess physiological potential of wheat seeds.

Optical and photoelectric properties of dry bacteriorhodopsin sensors

In this thesis, bacteriorhodopsin (BR) photosensor’s optical and electrical properties were studied. The BR sensor consisted of a dry film with BR in polyvinyl alcohol and covered with transparent conductors. In the experiments the BR photocycle was started with two lasers. The characteristics of the BR sensor were measured in two ways. The first approach was theoretical and it required knowing the laser parameters. The second way required assembling a measurement setup for the optical response measurements. However, no measurable results were obtained due to low laser power. The photoelectric response was measured in the experiments with two laser systems and the amplifier was tested. In the experiment with a Cavitar laser, the photoelectric response was obtained. In the experiment with FemtoFiber Pro laser, the photoelectric response was not measured. The expected amplitude of the response was obtained. The experimental data was analyzed and possible solutions for reducing the interference were given.

Physiological reactivity and the perception of emotional stimuli as they relate to social adaptive functioning after traumatic brain injury / y Melonie Jane Hopkins.

Traumatic brain injury (TBI) often affects social adaptive functioning and these changes in social adaptability are usually associated with general damage to the frontal cortex. Recent evidence suggests that certain neurons within the orbitofrontal cortex appear to be specialized for the processing of faces and facial expressions. The orbitofrontal cortex also appears to be involved in self-initiated somatic activation to emotionally-charged stimuli. According to Somatic Marker Theory (Damasio, 1994), the reduced physiological activation fails to provide an individual with appropriate somatic cues to personally-relevant stimuli and this, in turn, may result in maladaptive behaviour. Given the susceptibility of the orbitofrontal cortex in TBI, it was hypothesized that impaired perception and reactivity to socially-relevant information might be responsible for some of the social difficulties encountered after TBL Fifteen persons who sustained a moderate to severe brain injury were compared to age and education matched Control participants. In the first study, both groups were presented with photographs of models displaying the major emotions and either asked to identify the emotions or simply view the faces passively. In a second study, participants were asked to select cards from decks that varied in terms of how much money could be won or lost. Those decks with higher losses were considered to be high-risk decks. Electrodermal activity was measured concurrently in both situations. Relative to Controls, TBI participants were found to have difficulty identifying expressions of surprise, sadness, anger, and fear. TBI persons were also found to be under-reactive, as measured by electrodermal activity, while passively viewing slides of negative expressions. No group difference,in reactivity to high-risk card decks was observed. The ability to identify emotions in the face and electrodermal reactivity to faces and to high-risk decks in the card game were examined in relationship to social monitoring and empathy as described by family members or friends on the Brock Adaptive Functioning Questionnaire (BAFQ). Difficulties identifying negative expressions (i.e., sadness, anger, fear, and disgust) predicted problems in monitoring social situations. As well, a modest relationship was observed between hypo-arousal to negative faces and problems with social monitoring. Finally, hypo-arousal in the anticipation of risk during the card game related to problems in empathy. In summary, these data are consistent with the view that alterations in the ability to perceive emotional expressions in the face and the disruption in arousal to personally-relevant information may be accounting for some of the difficulties in social adaptation often observed in persons who have sustained a TBI. Furthermore, these data provide modest support for Damasio's Somatic Marker Theory in that physiological reactivity to socially-relevant information has some value in predicting social function. Therefore, the assessment of TBI persons, particularly those with adaptive behavioural problems, should be expanded to determine whether alterations in perception and reactivity to socially-relevant stimuli have occurred. When this is the case, rehabilitative strategies aimed more specifically at these difficulties should be considered.

Nietzsche's children : a physiological analysis of the scholar's task

Throughout Nietzsche's writings we find discussions of the proper relationship of the scholar/scientist to the philosopher, wi th the scholar of ten being presented in a derogatory light. In this thesis, I examine Nietzsche's por t rai t of the scholar through the lens of his physiological or clinical perspective as articulated by Dr. Daniel R. Ahern in his monograph entitled Nietzsche as Cultural Physician. My aim in doing so is to grasp the affirmative, creative aspect of this seemingly destructive polemic against scholars. I begin wi th a detailed discussion of Nietzsche's por t rai t of the scholar in Beyond Good and Evil. This includes an explication of Ahern's position, followed by an application of the diagnostic perspective to Nietzsche's discussion of the objective type, the skeptic, and the critic. I then look at how the characteristics of all three types are present in the Nietzschean 'free spirit.' I also discuss the physiological basis of esotericism in Nietzsche's work, as well as Nietzsche's revaluation of the scholarly vi r tue known as Red/ichkeit (or 'honesty'). I conclude wi th comments on the free spirit's relationship to the future.

Effects of Proactive and Retroactive Augmented Information on Physiological Responses in Learning a Novel Motor Skill

Previous research has demonstrated superior learning by participants presented with augmented task information retroactively versus proactively (Patterson & Lee, 2008; 2010). Theoretical explanations of these findings are related to the cognitive effort invested by participants during motor skill acquisition. The present study extended previous research by utilizing the physiological index, power spectral analysis of heart rate variability, previously shown to be sensitive to the degree of cognitive effort invested during the performance of a motor task (e.g., increase cognitive effort results in increased LF/HF ratio). Participants were required to learn 18 different key-pressing sequences. As expected, the proactive condition demonstrated superior RS during acquisition, with the retroactive condition demonstrating superior RS during retention. Measures of LF/HF ratio indicated the retroactive participants were investing significantly less cognitive effort in the retention period compared to the proactive participants (p< .05) as a function of learning.

The Fast Regulation of Photosynthesis in Diatoms: an inquiry into the physiological and physical origins of non-photochemical chlorophyll fluorescence quenching.

Diatoms are renowned for their robust ability to perform NPQ (Non-Photochemical Quenching of chlorophyll fluorescence) as a dissipative response to heightened light stress on photosystem II, plausibly explaining their dominance over other algal groups in turbulent light environs. Their NPQ mechanism has been principally attributed to a xanthophyll cycle involving the lumenal pH regulated reversible de-epoxidation of diadinoxanthin. The principal goal of this dissertation is to reveal the physiological and physical origins and consequences of the NPQ response in diatoms during short-term transitions to excessive irradiation. The investigation involves diatom species from different originating light environs to highlight the diversity of diatom NPQ and to facilitate the detection of core mechanisms common among the diatoms as a group. A chiefly spectroscopic approach was used to investigate NPQ in diatom cells. Prime methodologies include: the real time monitoring of PSII excitation and de-excitation pathways via PAM fluorometry and pigment interconversion via transient absorbance measurements, the collection of cryogenic absorbance spectra to measure pigment energy levels, and the collection of cryogenic fluorescence spectra and room temperature picosecond time resolved fluorescence decay spectra to study excitation energy transfer and dissipation. Chemical inhibitors that target the trans-thylakoid pH gradient, the enzyme responsible for diadinoxanthin de-epoxidation, and photosynthetic electron flow were additionally used to experimentally manipulate the NPQ response. Multifaceted analyses of the NPQ responses from two previously un-photosynthetically characterised species, Nitzschia curvilineata and Navicula sp., were used to identify an excitation pressure relief ‘strategy’ for each species. Three key areas of NPQ were examined: (i) the NPQ activation/deactivation processes, (ii) how NPQ affects the collection, dissipation, and usage of absorbed light energy, and (iii) the interdependence of NPQ and photosynthetic electron flow. It was found that Nitzschia cells regulate excitation pressure via performing a high amplitude, reversible antenna based quenching which is dependent on the de-epoxidation of diadinoxanthin. In Navicula cells excitation pressure could be effectively regulated solely within the PSII reaction centre, whilst antenna based, diadinoxanthin de-epoxidation dependent quenching was implicated to be used as a supplemental, long-lasting source of excitation energy dissipation. These strategies for excitation balance were discussed in the context of resource partitioning under these species’ originating light climates. A more detailed investigation of the NPQ response in Nitzschia was used to develop a comprehensive model describing the mechanism for antenna centred non-photochemical quenching in this species. The experimental evidence was strongly supportive of a mechanism whereby: an acidic lumen triggers the diadinoxanthin de-epoxidation and protonation mediated aggregation of light harvesting complexes leading to the formation of quencher chlorophyll a-chlorophyll a dimers with short-lived excited states; quenching relaxes when a rise in lumen pH triggers the dispersal of light harvesting complex aggregates via deprotonation events and the input of diadinoxanthin. This model may also be applicable for describing antenna based NPQ in other diatom species.

Post-hatch heat warms adult beaks: irreversible physiological plasticity in Japanese quail

Across taxa, the early rearing environment contributes to adult morphological and physiological variation. For example, in birds, environmental temperature plays a key role in shaping bill size and clinal trends across latitudinal/thermal gradients. Such patterns support the role of the bill as a thermal window and in thermal balance. It remains unknown whether bill size and thermal function are reversibly plastic. We raised Japanese quail in warm (308C) or cold (158C) environments and then at a common intermediate temperature. We predicted that birds raised in cold temperatures would develop smaller bills than warm-reared individuals, and that regulation of blood flow to the bill in response to changing temperatures would parallel the bill’s role in thermal balance. Cold-reared birds developed shorter bills, although bill size exhibited ‘catch-up’ growth once adults were placed at a common temperature. Despite having lived in a common thermal environment as adults, individuals that were initially reared in the warmth had higher bill surface temperatures than coldreared individuals, particularly under cold conditions. This suggests that blood vessel density and/or the control over blood flow in the bill retained a memory of early thermal ontogeny. We conclude that post-hatch temperature reversibly affects adult bill morphology but irreversibly influences the thermal physiological role of bills and may play an underappreciated role in avian energetics

Physiological and behavioural effects of dextroamphetamine on Beagle dogs : a placebo controlled study

Plusieurs articles scientifiques et manuels de référence en médecine comportementale distinguent l'hyperactivité ou hyperkinésie de l’activité excessive en évaluant la réponse physiologique et comportementale des chiens suite à l’administration per os de 0.2 à 1.0 mg/kg de dextroamphétamine. Selon ces références, le chien atteint d’un syndrome hyperactif ou hyperkinésie, répondra de façon paradoxale à cette médication par une diminution de l’activité motrice accompagnée d’une réduction minimale de 15% de la fréquence respiratoire et de la fréquence cardiaque. L’objectif de la présente étude était de mesurer la variation de la température corporelle, de la fréquence cardiaque, de l’activité motrice et de différents comportements spécifiques chez un groupe de Beagles ayant reçu de la dextroamphétamine. La fiabilité d'un accéléromètre comme mesure objective d’activité motrice a aussi été évaluée. Dans le cadre de cette étude croisée contrôlée par placebo, douze Beagles de la colonie de recherche âgés entre 13 et 20 mois ont reçu une dose orale de 0.2 mg/kg de dextroamphétamine. Le moniteur cardiaque Polar® et un accéléromètre Actical® ont été utilisés pour enregistrer la fréquence cardiaque et l’activité motrice avant et après l’administration de la médication. La durée de chacun des comportements spécifiques a été compilée à l’aide du logiciel Noldus® et la température corporelle a été prise par thermomètre rectal. Le modèle équilibré de mesures répétées indique que les sujets ayant reçu la dextroamphétamine montrent une réduction significative (p = 0.044) de leur fréquence cardiaque comparativement aux chiens ayant reçu le placebo. Aucune variation significative n'a été observée concernant la température corporelle, l'activité motrice, et les autres comportements (léchage des babines, halètements, et bâillements) suite à l’administration de la dextroamphétamine. Une corrélation significative, linéaire et positive (p < 0,0001) entre les périodes de mouvements observées (vidéo) et les mesures d’activité enregistrées par l’accéléromètre a été observée. Les résultats de cette étude indiquent que les Beagles peuvent afficher des effets paradoxaux dans les 90 minutes suivant l’administration per os de dextroamphétamine à raison de 0.2 mg/kg.

Monocouches peptidiques auto-assemblées et applications dans le domaine des biocapteurs de résonance de plasmon de surfaces

Ces travaux visent à étendre les applications de la résonance de plasmons de surface (SPR) L’objectif est d’offrir des outils diagnostics plus rapides, efficaces et simple d’utilisation pour diagnostiquer ou effectuer le suivi de conditions cliniques. Pour se faire, un nouveau type d’instrumentation SPR basé sur l’utilisation d’un prisme d’inversion (dove) a permis d’atteindre une limite de détection (LOD) de 10-6 unité d’indice de réfraction (RIU), une valeur comparable aux instruments commerciaux complexes tout en demeurant peu dispendieux, robuste et simple d’utilisation. Les travaux présentés dans cet ouvrage visent, dans un second temps, à réduire les interactions nonspécifiques (NSB) entre la surface des biocapteurs SPR et les composants de la matrice biologique complexe telles que: l’urine, le lysat cellulaire, le sérum et le sang. Ces dernières induisent des réponses empêchant l’utilisation de biocapteurs SPR en milieux complexes. Les acides aminés (AA) offrent une grande variété de propriétés physico-chimiques permettant la mise au point de monocouches auto-assemblées (SAM) aux propriétés diverses. Initialement, 19 des 20 acides aminés naturels ont été attachés à l’acide 3-mercaptopropionique (3-MPA) formant des SAMs peptidomimétiques. La quantité d’interactions nonspécifiques engendrées par ces différentes surfaces a été mesurée en exposant ces surfaces au sérum sanguin bovin complet variant de 400 ng/cm² jusqu’à 800 ng/cm². La détection à l’aide de ces surfaces de la β-lactamase (une enzyme responsable de la résistance aux antibiotiques au niveau μM) a démontré la possibilité d’employer ces surfaces pour bâtir des biocapteurs SPR. Des peptides de longueur allant de 2 à 5 résidus attachés à 3-MPA ont été synthétisés sur support solide. Cette étude a démontré que l’augmentation de la longueur des peptides formés d’AA résistants aux NBS accroit leur résistance jusqu’à 5 résidus. Le composé le plus performant de ce type (3-MPA-(Ser)5-OH) a permis d’atteindre 180 ng/cm². Cette valeur est similaire à celle des meilleures surfaces disponibles commercialement, notamment les surfaces de polyethylène glycol (PEG) à 100 ng/cm². Des surfaces de 3-MPA-(Ser)5-OH ont permis l’étalonnage de la β-lactamase et sa quantification directe dans un lysat cellulaire. La LOD pour ces biocapteurs est de 10 nM. Une troisième génération de surfaces peptidiques binaires a permis la réduction de la NSB jusqu’à un niveau de 23±10 ng/cm² une valeur comparable aux meilleures surfaces disponibles. Ces surfaces ont permis l’étalonnage d’un indicateur potentiel du cancer la metalloprotéinase-3 de matrice (MMP-3). Les surfaces formées de peptides binaires (3-MPA-H3D2-OH) ont permis la quantification directe de la MMP-3 dans le sérum sanguin complet. Une quatrième génération de surfaces peptidiques a permis de réduire davantage le niveau de NSB jusqu’à une valeur de 12 ± 11 ng/cm². Ces surfaces ont été modifiées en y attachant une terminaison de type acide nitriloacétique (NTA) afin d’y attacher des biomolécules marquées par six résidus histidines terminaux. Ces surfaces ont permis le développement d’une méthode rapide de balayage des ligands ciblant le « cluster of differenciation-36 » (CD36). L’étude d’électroformation des monocouches de peptide a permis de déterminer les conditions de formation optimales d’une couche de 3-MPA-HHHDD-OH permettant ainsi la formation de monocouches résistantes au NSB en moins de 6 minutes en appliquant un potentiel de formation de 200mV vs Ag/AgCl.