Subject of the study. Aerobic capacity and cardiac structure and function of healthy young males. Background. Data regarding the relationship between the parameters of aerobic capacity (such as maximal oxygen uptake or anaerobic threshold) and cardiac structure as well as function remain sparse and controversial. Aim. To determine how the parameters of aerobic capacity are correlated with those of cardiac structure and function. Objectives: 1. To determine the correlation between anaerobic thresholds and myocardial structure. 2. To determine how strongly the maximal oxygen uptake and cardiac structure are correlated. 3. To determine the correlation of indices of aerobic capacity to the parameters of myocardial function at rest. Hypothesis. Cardiac structure and function of healthy young men is directly linked not only to maximal oxygen uptake but anaerobic thresholds as well. Conclusions. The direct correlation of the parameters of concentric cardiac hypertrophy with aerobic capacity (anaerobic thresholds as well as maximal oxygen uptake) indices was detected. However, we failed to detect a significant correlation between indices of eccentric cardiac hypertrophy or myocardial function and aerobic capacity.

Previous research investigating endurance sports from a physiological perspectivehas mainly used constant or graded exercise protocols, although the nature ofsports like cross-country skiing and road cycling leads to continuous variations inworkload. Current knowledge is thus limited as regards physiological responses tovariations in exercise intensity. Therefore, the overall objective of the present thesiswas to investigate cardiovascular and metabolic responses to fluctuations inexercise intensity during exercise. The thesis is based on four studies (Studies I-IV);the first two studies use a variable intensity protocol with cardiorespiratory andblood measurements during cycling (Study I) and diagonal skiing (Study II). InStudy III one-legged exercise was used to investigate muscle blood flow duringvariable intensity exercise using PET scanning, and Study IV was performed toinvestigate the transition from high to low exercise intensity in diagonal skiing,with both physiological and biomechanical measurements. The current thesisdemonstrates that the reduction in blood lactate concentration after high-intensityworkloads is an important performance characteristic of prolonged variableintensity exercise while cycling and diagonal skiing (Studies I-II). Furthermore,during diagonal skiing, superior blood lactate recovery was associated with a highaerobic power (VO2max) (Study II). Respiratory variables such as VE/VO2, VE/VCO2and RER recovered independently of VO2max and did not reflect the blood lactate oracid base levels during variable intensity exercise during either cycling or diagonalskiing (Studies I-II). There was an upward drift in HR over time, but not inpulmonary VO2, with variable intensity exercise during both prolonged cyclingand diagonal skiing. As a result, the linear HR-VO2 relationship that wasestablished with a graded protocol was not present during variable intensityexercise (Studies I-II). In Study III, blood flow heterogeneity during one-leggedexercise increased when the exercise intensity decreased, but remained unchangedbetween the high intensity workloads. Furthermore, there was an excessiveincrease in muscular VO2 in the consecutive high-intensity workloads, mainlyexplained by increased O2 extraction, as O2 delivery and blood flow remainedunchanged. In diagonal skiing (Study IV) the arms had a lower O2 extraction thanthe legs, which could partly be explained by their longer contact phase along withmuch higher muscle activation. Furthermore, in Study IV, the O2 extraction in botharms and legs was at the upper limit during the high intensity workload with nofurther margin for increase. This could explain why no excessive increase inpulmonary VO2 occurred during diagonal skiing (Study II), as increased O2extraction is suggested to be the main reason for this excessive increase in VO2(Study III).

Tyrimo tikslas – nustatyti skirtingos lyties asmenų vegetacinių sistemų funkcijos rodiklių kaitos ypatumus pastovaus intensyvumo krūvio metu po ekscentrinio-koncentrinio prieškrūvio. Tyrimo uždaviniai: 1. Nustatyti ekscentrinio-koncentrinio prieškrūvio poveikį vegetacinių sistemų rodiklių kaitai atliekant vidutinio ir didelio intensyvumo aerobinį darbą. 2. Palyginti ekscentrinio-koncentrinio prieškrūvio poveikį vegetacinių sistemų rodiklių kaitai ir sukelto vėluojančio skausmo raumenyse poveikį atliekant įvairaus intensyvumo aerobinį darbą tarp skirtingos lyties asmenų. Tyrimo metodai ir organizavimas.Tyrimuose sutiko dalyvauti 18-ka tiriamųjų, merginos (n=10), kurių amžius buvo 20,9 (0,5) m. ir vaikinai (n=8), jų amžius – 20,8 (1,9) m. Siekiant nustatyti aerobinį pajėgumą tiriamieji po veloergometru „Ergoline –800“ (Vokietija) atliko nepertraukiamą nuosekliai kas 5 s didinamą krūv�� (NDK). Mynimo dažnumas buvo 70 k./min. Pirmas 3 minutes krūvis buvo 20 W, toliau krūvis buvo didinamas po 2 W iki nuovargio, t.y. tol, kol tiriamasis galėjo išlaikyti pastovų mynimo dažnumą. Pagal deguonies suvartojimo per paskutines krūvio 15 s priklausomybę nuo darbo galingumo buvo nustatomas maksimalus deguonies suvartojimas ( max). Pirmas ir antras ventiliaciniai slenksčiai (VeS1, VeS2) buvo nustatomi pagal Ve, o taip pat Ve/ ir Ve/VCO2 ekvivalentų priklausomybę nuo darbo galingumo. Po nepertraukiamo nuosekliai didinamo krūvio tiriamieji atliko individualizuotą vidutinio intensyvumo aerobinį... [toliau žr. visą tekstą] / The aim of this study was to ascertain the sex differences in the influence of prior eccentric-concentric load on the kinetics of cardiorespiratory parameters during constant intensity exercise. The tasks set were as follows: 1. To estimate the influence of prior eccentric-concentric load on the changes of cardiorespiratory parameters during moderate and high intensity exercises. 2. To compare sex differences in the influence of prior eccentric-concentric load on the changes of cardiorespiratory parameters and effect of delayed onset muscle soreness during various intensity exercises. Materials and methods. The subjects were ten healthy female 20,9 (0,5) years and eight healthy male 20,8 (1,9) years volunteered to participate in this study. The first test was used to measure their maximal oxygen uptake during an incremental exercise (3 min was 20 W and then 2 W/ 5s at 70 rev/min) to exhaustion on the cycle ergometer Ergoline-800 (Germany). Depending of in last 15 s on load output was determinate max. Both first and second ventilatory thresholds (VeS1, VeS2) were determinate by pulmonary ventilation (Ve) and depending of Ve/ and Ve/VCO2 equivalents on load output. Thereafter, the moderate intensity exercise (MI) corresponding to 80% of VeS1, and high intensity exercise (HI) corresponding to 50% of VeS2 and VeS1 inequality was determined individualized load for each subject. Cycling rapid was 70 rev./min. During whole tests of each respiratory period were recorded indices as... [to full text]

The difference in the ability of plants to obtain resources has been used to predict the competition outcomes. Competitive interactions between plants can be influenced by trophic interactions. If mycorrhizae increase the growth of inferior competitors, then it can prevent competitive exclusion. I examined the effect of mycorrhizae on competitive interactions and found that inferior competitors had slow growth in the absence of mycorrhizae, but greater growth with mycorrhizae. By providing greater growth responses to inferior versus superior competitors, mycorrhizae promoted coexistence. In a separate experiment, I looked at the effects of whole soil biota on competitive ability. Coexistence can occur if dominant competitors experience negative feedback and or if inferior competitors experience positive feedback. I examined Plantago lanceolata L. specific feedback effects on competitive ability of 21 co-occurring species. I found that feedback effects did not affect hierarchies, and that positive feedback did not improve species competitive ability. / NSERC (Natural Science and Engineering Research Council), University of Guelph, Queen Elizabeth II Graduate Scholarship for Science and Technology

It is well established that unaccustomed eccentric concentric exercise evokes delayed onset muscle soreness (DOMS) (MacIntyre et al., 2001; Dannecker et al., 2005, 2008; Fredsted et al., 2008; Lewis et al., 2012), muscle fibre disarrangement (Hortobagyi et., al., 1998; Stupka et al., 2001; Carlsson et al., 2007), inflammatory cell emission into blood (Stupka et al., 2001; Laaksonen et al., 2006), increase of the activity of blood plasma creatinkinasis (Stupka et al., 2000; Chen et al., 2010; Skurvydas et al., 2010), decrease of muscle force production (Chen et al., 2010; Semmler et al., 2007; Skurvydas et al., 2010) and decrease of aerobic work capacity (Black, Dobson, 2012). The aforementioned functional, sensory, biochemical and structural changes independently from each other are displayed immediately after eccentric exercise and stay for up to 7 days, dependence on the level of damage (Clarkson et al., 1992; Skurvydas et al., 2000; Stupka et al., 2000, 2001; MacIntyre, 2001; Totsuka et al., 2002; Nottle, Nosaka, 2007; Tofas et al., 2008; Lewis et al., 2012; Paulsen et al., 2012). It is still not clear what acute and residual effect of eccentric exercise on the pulmonary gas exchange is had during different intensity work. It was determined that one hour after eccentric concentric exercise, there increases absolute VO2 during moderate (Zaičenkovienė, Stasiulis, 2010) and heavy intensity loads (Ratkevičius et al., 2006). 48 hours after eccentric exercise, when the... [to full text] / Atlikta daug tyrimų, kuriais nustatyta, kad neįprasti ekscentriniai koncentriniai fiziniai pratimai sukelia vėluojantį raumenų skausmą (MacIntyre et al., 2001; Dannecker et al., 2005, 2008; Fredsted et al., 2008; Lewis et al., 2012), raumeninių skaidulų pažaidą (Hortobagyi et al., 1998; Stupka et al., 2001; Carlsson et al., 2007), uždegiminių ląstelių išskyrimą į kraują (Stupka et al., 2001; Laaksonen et al., 2006), kraujo plazmos kreatinkinazės aktyvumo padidėjimą (Stupka et al., 2000; Chen et al., 2010; Skurvydas et al., 2010), raumenų jėgos sumažėjimą (Chen et al., 2010; Semmler et al., 2007; Skurvydas et al., 2010) bei aerobinio darbo galingumo sumažėjimą (Black, Dobson, 2012). Minėti funkciniai, sensoriniai, biocheminiai ir struktūriniai pakitimai nepriklausomai vienas nuo kito pasireiškia iš karto po ekscentrinių krūvių ir išlieka iki 7 parų, priklausomai nuo pažaidos dydžio (Clarkson et al., 1992; Skurvydas et al., 2000; Stupka et al., 2000, 2001; MacIntyre, 2001; Totsuka et al., 2002; Nottle, Nosaka, 2007; Tofas et al., 2008; Lewis et al., 2012; Paulsen et al., 2012). Vis dar nėra aišku, koks yra ūminis ir liekamasis ekscentrinio krūvio poveikis kvėpavimo dujų apykaitos rodiklių kaitai įvairaus intensyvumo darbo metu. Nustatyta, kad, praėjus vienai valandai po ekscentrinio koncentrinio krūvio, padidėjo absoliučios VO2 reikšmės vidutinio (Zaičenkovienė, Stasiulis, 2010) ir didelio intensyvumo krūvių metu (Ratkevičius et al., 2006). Praėjus 48 val. po ekscentrinio... [toliau žr. visą tekstą]

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Escherichia coli has a proven track record for successful production of anything from small molecules like organic acids to large therapeutic proteins, and has thus important applications in both R&amp;D and commercial production. The versatility of this organism in combination with the accumulated knowledge of its genome, metabolism and physiology, has allowed for development of specialty strains capable of performing very specific tasks, opening up opportunities within new areas. The work of this thesis has been devoted to alter membrane transport proteins and the regulation of these, in order for E. coli to find further application within two such important areas. The first area was vaccine development, where it was investigated if E. coli could be a natural vehicle for live vaccine production. The hypothesis was that the introduction and manipulation of a protein surface translocation system from pathogenic E. coli would result in stable expression levels of Salmonella subunit antigens on the surface of laboratory E. coli. While different antigen combinations were successfully expressed on the surface of E. coli, larger proteins were affected by proteolysis, which manipulation of cultivation conditions could reduce, but not eliminate completely. The surface expressed antigens were further capable of inducing proinflammatory responses in epithelial cells. The second area was biorefining. By altering the regulation of sugar assimilation, it was hypothesized that simultaneous uptake of the sugars present in lignocellulose hydrolyzates could be achieved, thereby improving the yield and productivity of important bio-based chemicals. The dual-layered catabolite repression was identified and successfully removed in the engineered E. coli, and the compound (R)-3-hydroxybutyric acid was produced from simultaneous assimilation of glucose, xylose and arabinose. / <p>QC 20150508</p>

Salinity and oxygen availability have long been recognised as important factors influencing animal physiology and therefore species distribution. The maintenance of appropriate cellular ion levels is critical for many essential physiological processes, but at the same time is energetically expensive. Since hypoxia is likely to impose aerobic limitations for ATP generation, the maintenance of salt and water homeostasis could be at risk during hypoxia. The amphidromous inanga (Galaxias maculatus) is well known for its salinity tolerance and its life cycle that involves several salinity related migrations. During these migrations inanga also frequently encounters hypoxic waters, and therefore must maintain energy homeostasis when aerobic metabolism may be compromised. The present study has investigated behavioural, physiological, biochemical and molecular mechanisms by which inanga tolerate changes in salinity and hypoxia. After 14 days of acclimation to salinities ranging from freshwater to 43‰, inanga showed physiological acclimation. This was evident by no changes in metabolic rates or energy expenditures through this salinity range. Energy balance seemed to be tightly and efficiently controlled by changes in the proportion of protein and lipids used as energy substrate. No mortalities and only minor changes in plasma osmolality also indicated salinity acclimation. The remarkable osmoregulatory capacity of inanga was also evidenced after a seawater challenge. The osmotic balance of inanga was only disrupted during the first 24 hours after the challenge, evidenced by an increase in plasma osmolality and plasma Na+, and a decrease in muscle water content. These physiological changes were correlated with changes at the molecular level. Different isoforms of the catalytic subunit of the Na+,K+-ATPase (NKA) were isolated, partially sequenced and identified in inanga. Phylogenetic analysis grouped inanga isoforms (α-1a, α-1b, α-1c) with their respective homologues from salmonids. Patterns of mRNA expression were also similar to salmonids, with α-1a being downregulated and α-1b being up-regulated following seawater challenge. Previous to this study, NKA isoform switching was reported to occur only in salmonids and cichlids. The presence of NKA subunits that change with environmnetal salinity in inanga indicates that this isoform switching phenomenon is much more widespread among teleost lineages than previously thought. Aiming to elucidate the hypoxia tolerance of inanga, oxygen consumption rate as a function of decreasing external PO2 was evaluated. At no point did inanga regulate oxygen consumption, suggesting that this species is an oxyconformer. This is the first robust demonstration of the existence of oxyconforming in fish. Evaluation of the scaling relationship between oxygen consumption and fish size in normoxia, showed that the exponent of this relationship fell within the range previously reported for fish. However, in hypoxic conditions the scaling relationship was less clear suggesting different size-related mechanisms for tolerating hypoxia. Analysis of the aerobic and anaerobic metabolism of small and large fish, showed that smaller inanga were able to sustain aerobic metabolism for longer than larger inanga, which instead relied on anaerobic metabolism for extending their survival. This knowledge is likely to be of value for the conservation of this iconic fish species, by incorporating these size related differences in hypoxia tolerance in streams management. In light of the unusual oxyconforming response of inanga, a study examining the behavioural responses of this species to declining dissolved oxygen was performed. Inanga did not display a behaviour that might reduce energy expenditure during oxygen limitation; instead swimming activity and speed were elevated relative to normoxia. As hypoxia deepened inanga leaped out of the water, emersing themselves on a floating platform. Once emersed, fish exhibited an enhanced oxygen consumption rate compared to fish that remained in hypoxic water. Although this emersion behaviour was hypothesised to be of physiological advantage, both aquatic hypoxia and emersion resulted in similar physiological and biochemical consequences in inanga. While in hypoxic water oxygen availability seemed to be the limiting factor, in air failure of the circulatory system was hypothesised to be the cause of a similar metabolic signature to that found in aquatic hypoxia. Overall, inanga seemed to be not particularly well adapted to tolerate aquatic hypoxia. In light of the increasing likelihood of anthropogenic-induced hypoxia in inanga habitats, this is likely to have negative consequences for the future of inanga populations in the wild. Although this study provides the mechanisms behind the exceptional salinity tolerance of inanga, its susceptibility to hypoxia is likely to impose further constraints for the osmoregulatory processes that guarantee inanga survival during life cycle migrations. The results of the present study are relevant for understanding and managing the fishery of this economically- and culturally important fish species.

The aim of this study was to investigate the effect the plant matrix and the structure of the flavonoid (i.e. whether aglycone or glycoside) may have on the gastrointestinal uptake and metabolism of luteolin derivatives from Artemisia afra traditional plant medicine. Specifically, how these two factors influenced the intestinal uptake and disposition of luteolin derivatives in pure and in Artemisia afra plant extract forms were to be assessed by investigating the uptake and metabolism of the luteolin derivatives in human intestinal epithelial Caco-2 cells and the perfused rat intestinal loop. To realize this aim, the following were determined: (1) identification and characterization of major luteolin derivatives found in Artemisia afra, (2) the effect of the plant matrix on the uptake of luteolin derivatives in Artemisia afra aqueous-extract forms across the Caco-2 cell monolayer, (3) the effect of the plant matrix on the absorption and metabolism of luteolin derivatives in Artemisia afra aqueous-extract forms in the perfused rat small intestine, (4) the effect of gut contents on the uptake and metabolism of luteolin derivatives in intestinal loop and (5) the metabolic profiles of luteolin derivatives obtained for the pure solutions versus plant aqueous extract solutions in Caco-2 cells and the rat intestine. / Philosophiae Doctor - PhD