No description available.

Members of the genus Bacillus are mainly Gram positive, aerobic rod shaped, endospore-forming bacteria that are increasingly being recognised for their ability to promote plant growth and antagonise fungal pathogens. From a biological control perspective, Bacillus spp. strains that produce antifungal compounds are of particular interest. In this study, aerobic endospore-formers were isolated from an undisturbed indigenous grassland soil and screened for antifungal activity and other plant growth promoting traits. Endospore-formers were also isolated from rhizosphere soil associated with the roots of maize, wheat and kale grown in pots containing soil from the same grassland site. Microbial diversity amongst isolates showing antifungal activity was investigated using different molecular fingerprinting methods, namely, intergenic transcribed spacer–PCR (ITS-PCR), random amplified polymorphic DNA-PCR (RAPD-PCR) and 16S rRNA gene amplification and sequencing. Characterization of the active antimicrobial compound(s) associated with selected isolates was also attempted. Prior to isolating from bulk and rhizosphere soils, samples were pre-heated to eliminate heat sensitive vegetative cells. Mean endospore counts were; wheat rhizosphere, Log 6.03 c.f.u g-1 soil; maize rhizosphere, Log 5.88 c.f.u g-1 soil; kale rhizosphere Log 5.90 c.f.u g-1 soil; and bulk soil Log 5.67 c.f.u g-1soil. A total of three hundred and eighty-four isolates were screened for antagonism towards Rhizoctonia solani using dual-culture plate bioassays. Thirty four of the isolates (~9%) mostly isolated from the bulk soil inhibited R. solani at varying degrees. Differences in antimicrobial interactions were apparent in in vitro bioassay; supposedly due to different concentrations and/or types of antimicrobial compounds. Biochemical tests for amylase, cellulase, chitinase, and proteinase activity, siderophore production and inorganic phosphate solubilisation were conducted. None of the isolates possessed all of these attributes and only a few showed multiple traits. Ninety-one percent of the isolates exhibited proteinase activity, 76% were able to hydrolyze starch whereas only four displayed cellulase activity. Only four isolates from the bulk-soil were capable of solubilising inorganic phosphate. ITS-PCR and 16S rRNA gene sequence analysis showed high levels of genetic homology amongst isolates and the majority were closely associated with representatives of the B. cereus group. Isolate C76 was the exception, being closely matched with B. subtilis. ITS-PCR banding profile was useful for distinguishing between species but did not distinguish within species. RAPD-PCR distinguished finer levels of genetic diversity between and within sample sets, with primer OPG-11 showing the greatest levels of heterogeneity. DNA extraction methods and the influence of template DNA dilution were investigated to determine their influence on RAPD-PCR analysis reproducibility. Prominent bands were comparable for crude template- and kit-extracted DNA but slight changes in band intensity and in some instances, additional faint bands were observed. At the highest DNA concentrations tested (7 μg/ml), further bands with molecular weights above 2.5 kbp were apparent. Strict standardization of PCR conditions greatly reduced variability of the RAPD-PCR analysis. Isolates from the different sample sets were screened for the presence of genetic markers associated with the biosynthesis of zwittermicin A, an aminopolyol antibiotic produced by some members of the B. cereus group. In an initial screen only one isolate, W96, yielded PCR amplicons consistent with those previously reported in the literature for the zwittermicin A genes. Later a further sixteen isolates grouped with W96 on the basis of the RAPD-PCR fingerprinting profiles, were screened for the presence of these genes. Of these, only six showed PCR amplification products similar to W96. Sequence homology testing against the GenBank database confirmed the presence of the zwittermicin A genes in these isolates. Isolate W96 was selected for further extraction and characterization of its antifungal compound(s). However, after culturing in various broth media cell free supernatants of W96 failed to show antifungal activity in vitro even when the supernatants were concentrated 20-fold. These findings provide a general overview of the diversity of aerobic endospore-forming bacteria present in an undisturbed indigenous grassland soil that exhibited antifungal activity in vitro and the limited influence tested crop rhizospheres have on this diversity. Combined use of ITS-PCR, 16S rRNA sequencing and RAPD-PCR techniques served as a rapid and effective means of grouping isolates for further investigations of their potential use as biocontrol agents and plant growth promoting rhizobacteria. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Antarctic fish from the Perciform suborder Notothenioidei inhabit arguably the most thermally stable ocean environment on earth. In order to populate the subzero environment Antarctic fish have evolved numerous adaptations. However, specialisation to -1.9°C has incurred a trade off, thermal flexibility is lost likely due to modifications to the cold and as a result Notothenioidei are extremely stenothermic. Climate change mediated warming is predicted to increase the ocean temperature surrounding the Antarctic continent by 2°C within the next century. This increase is projected to affect individuals, populations and the community structures of those inhabiting the area and therefore the physiological study of the acclimation ability and thermal limitations of Antarctic fish is an area scientific interest. The present study is a series of discrete experiments relating to one species, Trematomus bernacchii, a circumpolar benthic Notothenioidei found in nearly all inshore waters surrounding the Antarctic coastline. These studies included investigation of the response of this species to both chronic and acute temperature exposure prior to and following a feeding event, a reduction in environmental oxygen and an exhaustive exercise event, as well as examination of T. bernacchii ability to recovery from these challenges. T. bernacchii demonstrated variable success when acclimated to +3°C. Failure appeared to be determined by the recovery period following capture and aquarium housing, 7 days housing following capture resulted in 100% mortality, conversly 3 months resulted in 100% survival. Following successful acclimation T. bernacchii showed physiological adjustment as acclimated resting metabolic rate mirrored that of T. bernacchii tested at environmental temperature, 20.63 ± 1.3 compared to 22.38 ± 1.02 mg. O₂. kg⁻¹. h⁻¹. The previously undefined specific dynamic action response (SDA), in T. bernacchii was characteristic of polar species. At environmental temperatures SDA scope was small 14.52 ± 3.52 mg O₂. kg⁻¹. h⁻¹, and lengthy ,72 hours; SDA duration was reduced to 9 hours in acclimated fish. Resting metabolic rate was elevated following acute exposure to +3°C, 34.27 ± 2.35 mg O₂. kg⁻¹. h⁻¹, masking the SDA response and associated parameters. T. bernacchii were relatively sensitive to hypoxia, Pcrit over four acute temperature exposures, ranged between 69 and 102mmHg, higher than the average range for teleosts (40 – 60 mmHg). Above -1°C Pcrit increased, rising with acute temperature exposure. Ventilation rate was temperature dependent and completely absent at +4 and +6°C. A bradycardia (beginning at 60 and 70mmHg) was observed at all temperature exposures, this response was consistent as all heart rates reduced by 25%. Recovery from both hypoxia and acute temperature exposure was rapid. Following an exhaustive exercise event aerobic Scope of T. bernacchii was constrained over an acute temperature increase, reducing from 38.58 ± 5.64 to 24.41 ± 4.92 mg.O₂. kg⁻¹.h⁻¹ over a 7°C temperature increase, respiratory scope too was reduced such that at +4 and +6°C scope was absent. Heart rate of T. bernacchii was highly constrained at -1°C, increasing by 2.54 ± 0.9 bpm following exercise. Acute temperature increase resulted in an increase in cardiac scope, maximum 6.29 ± 1.2 bpm at +2°C, due likely to a thermally mediated loss of cholinergic tonus following exhaustive exercise. Recovery of all parameters was temperature dependent and rapid upon return to -1°C. The present study is the first to quantify and assess the effect of acute and chronic temperature exposure on the SDA response of T. bernacchii. Furthermore, it supplements the current literature on acclimation ability, acute temperature exposure, aerobic scope and hypoxia tolerance for this species. This work will be of use in future investigations of the effects of rapid climate change on Antarctic notothenioid fish and the interconnected ecosystem.

The Surgeon General's Report on Physical Activity and Health recommends expending 200 kcals "on most, if not all days of the week" (1000 to 1400 kcals/week) as a minimum quantity of exercise energy expenditure (EE) required to obtain health benefits. The ACSM recommends expending a minimum of 1000 kcals/week to receive fitness benefits. The purpose of this study was to evaluate the effect of EE above and below 1200 kcals/week on health and fitness benefits. Twenty-six previously sedentary males and females (mean age = 47 ± 2 years), with at least one risk factor for CAD completed the 22-32 week endurance exercise training study. Subjects performed an initial health screening and treadmill test which included measures of heart rate, blood pressure, blood lipids, body composition at rest, and metabolic data (V02, VE, RER) during the maximal treadmill test. Subjects began exercising with the Adult Physical Fitness Program at a self-selected amount of energy expenditure, recording heart rate, frequency, and duration of exercise on an exercise log card after every exercise session. After 22-32 weeks, subjects returned to the laboratory for a final evaluation identical to the first. The metabolic data from the initial and final tests, along with the data from the exercise log card was used to develop an estimation of energy expenditure/week. Subjects were then categorized into either < or > 1200 kcal/week energy expenditure. Results of the pre/post (n=12) training blood pressure, blood lipids, body composition and V02 __ measures were:EE <1200 kcalsEE >1200 kcalsVariablePre TrainingPost TrainingPre Training 'PostTrainingVO2.(L/min)2.287+.1982.397±.1983.064±.2073.290±.210VO2.(ml/kg/min)27.4+1.7-28.2+1.7-33.0+2.4-37.3±2.6 #HDL-C(mg/dl)51+4.355±4.547±2.850±3.2SBP(mmHg)121±4117±3124±4y120±37BMI(k g/m2)28.0±1.728.3+1.731.2+1.6730.0+1.5y #*p <0.05 training main effect, #p < 0.05 group by time interaction, y: n=14The group that expended above 1200 kcals/week displayed more improvement inrelative V02 n,.,., and BMI following the training program than the group thatexpended less than 1200 kcals/week. Furthermore, there was a training main effect showing adaptations in V02 ., HDL and SBP. In conclusion, previously at risk, sedentary individuals exercise training > 2 days/week can receive health and fitness benefits. However, those expending more than 1200 kcals/week will receive a greater benefit in terms of body composition and cardiovascular fitness. / School of Physical Education

Šiuolaikinis mokslas fizinį aktyvumą pripažįsta kaip vieną iš sveikatos garantų, ypač prognozuojant sergamumo lėtinėmis ligomis rizikos laipsnį (Lochman ir kt.,2008). Judėjimo stoka jau seniai analizuojama kaip atskira sveikatos problema: didėja rizika atsirasti viršsvoriui, nutukimui ir kitoms chroniškoms su svoriu susijusioms sveikatos problemoms, pavyzdžiui, širdies ir kraujagyslių ligoms bei diabetui, kurie blogina gyvenimo kokybę, kelia pavojų gyvybei ir yra didelė našta sveikatos biudžetui bei ekonomikai (Bouchard ir kt.,1994, Parks ir kt.,2003). Todėl svarbu, kad ES valstybės narės parengtų nacionalinius fizinio aktyvumo skatinimo planus, siekdamos pakeisti nesveikus gyvensenos įpročius ir padėti visuomenei suvokti fizinio aktyvumo naudą sveikatai. Lietuvos Respublikos Seime 2007 m. svarstytoje “Lietuvos gyventojų 2008 – 2020 metų fizinio aktyvumo skatinimo strategijoje” akcentuojama, kad pakankamai fiziškai aktyvūs yra mažiau nei ketvirtadalis suaugusiųjų ir mažiau nei pusė vaikų. Vis dėlto didėjantis sporto klubų ir juose besilankančiųjų skaičius rodo, kad gyventojų domėjimasis asmenine kūno kultūra, fiziniu pajėgumu auga (Zuozienė, Rėklaitienė, 2010). Atėję į sporto klubą klientai reikalauja iš sporto specialisto patrauklios treniruotės programos, naujausių metodikų, saugių sporto priemonių ir aplinkos. Be to, būtinas individualus dėmesys kiekvienam sportuojančiam. Siekiama, kad treniruotės programos būtų ne tik veiksmingos, saugios, bet ir pasiekti rezultatai... [toliau žr. visą tekstą] / Contemporary science considers physical activity as one of the guarantees for enhancing health, in particular providing prognosis on the level of chronic diseases (Lochman et al., 2008). Lack of movement has been under analysis for many years as a separate health problem, as it gives preconditions for overweight, obesity and other obesity related chronic health problems, such as cardiovascular diseases and diabetes, which in turn worsen the quality of a persons’ living, are dangerous for one’s life, altogether being a huge burden for the budget of health sector and economics in general (Bouchard et al., 1994, Parks et al., 2003). Thus, important task raised for the EU member states is to prepare national plans for the citizens’ physical activity reinforcement in order to change the unhealthy habits of population and help them to perceive the benefits of physical activity. “The strategy of Lithuanian citizens’ physical activity promotion for 2008-2020” (discussed in Seimas of the Republic of Lithuania) points out the fact that only less than one fourth of the adults and less than a half of children can be considered as an increase of people’s interest in personal physical education and physical fitness (Zuozienė, Rėklaitienė, 2010). The visitors of the sport club raise rather high requirements for the sport specialist, such as an attractive program, newest methodic, safe sport means and environment. Besides, individual approach to each of the client is necessary. Training... [to full text]

The incidence of stroke is increasing and is expected to continue to increase with the aging population, escalating rates of obesity and physical inactivity, and the rising prevalence of heart failure. Stroke is a leading cause of long-term disability, which includes approximately half of survivors that experience cognitive impairment. It is accepted that aerobic exercise can improve physical health in both healthy and stroke populations. Evidence also suggests aerobic exercise may positively affect cognitive function among healthy adults; however, whether there are similar beneficial effects among stroke survivors remains unclear. The purpose of this thesis was to examine whether a single session of moderate intensity aerobic exercise acutely improves cognitive function, specifically executive function, in comparison to a rest control among people with chronic stroke. Our first objective was to determine whether aerobic exercise alters cortical processing, as measured by P300 amplitude and latency during a modified Eriksen Flanker task. The second objective was to investigate whether aerobic exercise influences behavioral measures of response time and accuracy during a modified Eriksen Flanker task. Finally, the third objective was to examine the time course of effects up to 40 minutes after exercise cessation. In our sample, participants had shorter P300 latency and larger P300 amplitude 20 to 40 minutes after exercise cessation in comparison to rest. There were no significant behavioural changes. These findings suggest that aerobic exercise may enhance, or at least maintain cognitive processing speed and attention 20 to 40 minutes after exercise cessation, which otherwise deteriorated in the rest condition. Although results should be viewed cautiously due to a small sample size, these findings have potential implications for stroke rehabilitation. Our results suggest that aerobic exercise may be able to improve attentional focus during subsequent rehabilitation exercises for up to 40 minutes or more. Future research should examine whether the effects of various exercise doses and whether paired exercise and rehabilitation improves clinical outcomes.

Previous studies have come to contrasting conclusions regarding nutrient limitation of hydrocarbon biodegradation in the Gulf of Mexico, and rate measurements are needed to support oil plume modeling. Thus, this study investigates the rates and controls of biodegradation in seawater and sediments, largely in the deepsea. Sediment and seawater samples were collected on research cruises in the northern Gulf from 2012 to 2014, where the seafloor was impacted by the Deepwater Horizon (DWH) oil spill. Biodegradation was clearly limited by both nitrogen and phosphorus availability in surface waters with significant rates of CO₂ production (100 μmol CO₂ l⁻¹ d⁻¹) only observed in treatments amended with ammonium and phosphate. In deepsea sediments, nutrient amendments resulted in an average of 6 fold higher degradation rates (0.49 μmol CO₂ g sed⁻¹ d⁻¹) compared to unamended controls. Microbial communities responded to oil contamination rapidly in a series of enrichment cultures, and selection was observed for populations of native hydrocarbon-degrading bacteria. Temperature was shown to be a major factor in controlling microbial community composition in the enrichments. At room temperature, community diversity in the enrichments was significantly reduced in the presence of oil, while under 4 °C, the community diversity and evenness remained relatively high upon oil amendment. From the same deepsea sediments, 30 strains of known oil-degrading bacteria (Rhodococcus and Halomonas) were enriched and isolated with hexadecane, phenanthrene, and Macondo oil as the sole carbon and energy source. Detection of these strains in sequence libraries indicates that they may have contributed to the degradation of oil deposited onto the sediments. Rhodococccus strain PC20 degraded approximately one-third of total petroleum hydrocarbons amended into cultures within 7 days. This work elucidates the controls of biodegradation and we provide model pure cultures to further elucidate the ecophysiology of hydrocarbon degradation, focusing on deepsea sediments of the northern Gulf of Mexico.

This dissertation examines the impact of exercise rehabilitation and the components of exercise prescriptions on optimizing health outcomes for people with diabetes (DM). Exercise is an accepted part of the diabetes management regime to help prevent or slow the progression of the disease. A combined aerobic and resistance training protocol is the recommended exercise regime for people with DM, but the question remains as to what the optimal dose may be for glycemic control and reduction of cardiovascular risk. This thesis aims to address three objectives surrounding optimal exercise prescriptions for diabetes: 1) To investigate aerobic exercise prescription efficacy in people with DM, coronary artery disease (CAD) and both CAD and DM to determine if there are population-specific VO2peak responses to exercise prescription; 2) To determine the optimal volume and intensity of resistance training exercise, in combination with aerobic training, that may improve glucose control, cardiovascular risk factors and body composition in people with type 2 DM (T2DM); and 3) To study the relationship between exercise performance, physiological changes and depressive mood in people with T2DM participating in a supervised, exercise program. Encouraging participation in an appropriately prescribed aerobic and resistance training program may help to improve adherence to exercise and elicit optimal health outcomes in people with T2DM. Tailoring the exercise prescription to suit the patient’s lifestyle, history and capacity is the utmost challenge for health care providers who hope to provide a complementary, non-pharmacologic therapeutic option for their patients.

Increasing evidence supports the use of physical activity for modifying brain activity and overall neurological health (Hillman et al, 2008). Specifically, aerobic exercise appears to improve cognitive efficacy with regards to decisional oddball tasks shown through the P300, whose amplitude and latency is augmented (Magnié et al., 2000). Furthermore, the effects of an acute bout of aerobic exercise on cardiovascular function are well established and are sustained following exercise cessation. Based on these findings, we proposed that (1) an acute bout of exercise may modulate movement-related cortical excitability within motor areas and (2) that transient effects would be sustained as long as heart rate (HR) remained elevated. Subjects (n=23) were placed in a soundproof booth and instructed to perform a self-paced unimanual ballistic wrist extension every 3-6 seconds of the right wrist while holding a moveable handle. The motion involved a brisk contraction followed by relaxation and positional reset, collected continuously for approximately 8 minutes. Electroencephalography was used to measure movement-related cortical activity of the Bereitschaftspotential (BP) time-locked to onset of muscle activity associated with movement. The BP is a slow negative self-paced movement related cortical potential that precedes movement by approximately 1500ms. Current work commonly separates the BP into 3 main components early, late, and re-afferent Potentials. The early BP is representative of motor preparation of supplementary motor area (SMA) activity while the late component is representative of motor execution from primary motor cortex (M1). Early and late components are often distinguished by a a characteristic change in slope; where the early BP is a slow negative rise and the late components a steeper negative deflection beginning approximately 500ms prior to movement onset. Broken down further the late component consists of a portion of negative slope before giving rise to a peak approximately 100ms after movement onset known as the motor potential (MP). Following baseline measures, subjects performed 20 minutes of aerobic exercise at a moderate intensity (70% of age-predicted maximum heart rate) on a recumbent cycle ergometer. After the cessation of exercise, BP measures were recorded at two time points: immediately post-exercise (Post) and following a return to iv baseline HR (Post[Rest]) and two additional measures separated by 15 minutes each (Post[Rest2] and Post[Rest3]) which was, on average, 45 minutes after the cessation of exercise. Electromyography (EMG) was employed over the extensor carpi radialis muscle belly to describe muscle burst activity and onset characteristics. Results determined that Early but not Late BP was influenced by aerobic exercise. This early movement related cortical adaptation is indicative of enhanced processing within supplementary motor area. Moreover, this effect was sustained for up to an hour and 15 minutes following exercise cessation. This data is suggestive that aerobic exercise influences on motor related cortical excitability is not driven by an aerobic exercise effect and is more indicative of a delayed neurotransmitter effect.

No description available.