183 research outputs found
FORMATION OF SCIENTIFIC OUTLOOK OF FUTURE SPECIALISTS – KEY TO EFFICIENCY OF EDUCATIONAL ACTIVITIES
Professional and educational atmosphere in medical schools should promote the proper formation of the personality of the future doctor in his development of critical analytical thinking, and as a result is the sustainable scientific outlook
Environmental Stress-Dependent Effects of Deletions Encompassing Hsp70Ba on Canalization and Quantitative Trait Asymmetry in Drosophila melanogaster
Hsp70 genes may influence the expression of wing abnormalities in Drosophila melanogaster but their effects on variability in quantitative characters and developmental instability are unclear. In this study, we focused on one of the six Hsp70 genes, Hsp70Ba, and investigated its effects on within-and among-individual variability in orbital bristle number, sternopleural bristle number, wing size and wing shape under different environmental conditions. To do this, we studied a newly constructed deletion, Df(3R)ED5579, which encompasses Hsp70Ba and nine non-Hsp genes, in the heterozygous condition and another, Hsp70Ba304, which deletes only Hsp70Ba, in the homozygous condition. We found no significant effect of both deletions on within-individual variation quantified by fluctuating asymmetry (FA) of morphological traits. On the other hand, the Hsp70Ba304/Hsp70Ba304 genotype significantly increased among-individual variation quantified by coefficient of variation (CV) of bristle number and wing size in female, while the Df(3R)ED5579 heterozygote showed no significant effect. The expression level of Hsp70Ba in the deletion heterozygote was 6 to 20 times higher than in control homozygotes, suggesting that the overexpression of Hsp70Ba did not influence developmental stability or canalization significantly. These findings suggest that the absence of expression of Hsp70Ba increases CV of some morphological traits and that HSP70Ba may buffer against environmental perturbations on some quantitative traits
Adaptation to fluctuating environments in a selection experiment with Drosophila melanogaster
A fundamental question in life-history evolution is how organisms cope with fluctuating environments, including variation between stressful and benign conditions. For short-lived organisms, environments commonly vary between generations. Using a novel experimental design, we exposed wild-derived Drosophila melanogaster to three different selection regimes: one where generations alternated between starvation and benign conditions, and starvation was always preceded by early exposure to cold; another where starvation and benign conditions alternated in the same way, but cold shock sometimes preceded starvation and sometimes benign conditions; and a third where conditions were always benign. Using six replicate populations per selection regime, we found that selected flies increased their starvation resistance, most strongly for the regime where cold and starvation were reliably combined, and this occurred without decreased fecundity or extended developmental time. The selected flies became stress resistant, displayed a pronounced increase in early life food intake and resource storage. In contrast to previous experiments selecting for increased starvation resistance in D. melanogaster, we did not find increased storage of lipids as the main response, but instead that, in particular for females, storage of carbohydrates was more pronounced. We argue that faster mobilization of carbohydrates is advantageous in fluctuating environments and conclude that the phenotype that evolved in our experiment corresponds to a compromise between the requirements of stressful and benign environments
Proteomic data reveal a physiological basis for costs and benefits associated with thermal acclimation
Physiological adaptation through acclimation is one way to cope with temperature changes. Biochemical studies on acclimation responses in ectotherms have so far mainly investigated consequences of short-term acclimation at the adult stage and focussed on adaptive responses. Here, we assessed the consequences of rearing Drosophila melanogaster at low (12°C), benign (25°C) and high (31°C) temperatures. We assessed cold and heat tolerance and obtained detailed proteomic profiles of flies from the three temperatures. The proteomic profiles provided a holistic understanding of the underlying biology associated with both adaptive and non-adaptive temperature responses. Results show strong benefits and costs across tolerances: rearing at low temperature increased adult cold tolerance and decreased adult heat tolerance and vice versa with development at high temperatures. In the proteomic analysis, we were able to identify and quantify a large number of proteins compared with previous studies on ectotherms (1440 proteins across all replicates and rearing regimes), enabling us to extend the proteomic approach using enrichment analyses. This gave us detailed information on individual proteins, as well as pathways affected by rearing temperature, pinpointing potential mechanisms responsible for the strong costs and benefits of rearing temperature on functional phenotypes. Several well-known heat shock proteins, as well as proteins not previously associated with thermal stress, were among the differentially expressed proteins. Upregulation of proteasome proteins was found to be an important adaptive process at high-stress rearing temperatures, and occurs at the expense of downregulation of basal metabolic functions
Trans-generational plasticity in response to immune challenge is constrained by heat stress
Trans-generational plasticity is the adjustment of phenotypes to changing habitat conditions that persist longer than the individual lifetime. Fitness benefits (adaptive TGP) are expected upon matching parent-offspring environments. In a global change scenario, several performance-related environmental factors are changing simultaneously. This lowers the predictability of offspring environmental conditions, potentially hampering the benefits of trans-generational plasticity. For the first time, we here explore how the combination of an abiotic and a biotic environmental factor in the parental generation plays out as trans-generational effect in the offspring.
We fully reciprocally exposed the parental generation of the pipefish Syngnathus typhle to an immune challenge and elevated temperatures simulating a naturally occurring heatwave. Upon mating and male pregnancy, offspring were kept in ambient or elevated temperature regimes combined with a heat-killed bacterial epitope treatment. Differential gene expression (immune genes and DNA- and histone-modification genes) suggests that the combined change of an abiotic and a biotic factor in the parental generation had interactive effects on offspring performance, the temperature effect dominated over the immune challenge impact. The benefits of certain parental environmental conditions on offspring performance did not sum up when abiotic and biotic factors were changed simultaneously supporting that available resources that can be allocated to phenotypic trans-generational effects are limited. Temperature is the master regulator of trans-generational phenotypic plasticity, which potentially implies a conflict in the allocation of resources towards several environmental factors. This asks for a reassessment of trans-generational plasticity as a short-term option to buffer environmental variation in the light of climate change
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Obesity, diabetes and longevity in the Gulf: is there a Gulf Metabolic Syndrome?
The Gulf is experiencing a pandemic of lifestyle-induced obesity and type 2 diabetes mellitus (T2DM), with rates exceeding 50 and 30%, respectively. It is likely that T2DM represents the tip of a very large metabolic syndrome iceberg, which precedes T2DM by many years and is associated with abnormal/ectopic fat distribution, pathological systemic oxidative stress and inflammation. However, the definitions are still evolving with the role of different fat depots being critical. Hormetic stimuli, which include exercise, calorie restriction, temperature extremes, dehydration and even some dietary components (such as plant polyphenols), may well modulate fat deposition. All induce physiological levels of oxidative stress, which results in mitochondrial biogenesis and increased anti-oxidant capacity, improving metabolic flexibility and the ability to deal with lipids. We propose that the Gulf Metabolic Syndrome results from an unusually rapid loss of hormetic stimuli within an epigenetically important time frame of 2-3 generations. Epigenetics indicates that thriftiness can be programmed by the environment and passed down through several generations. Thus this loss of hormesis can result in continuation of metabolic inflexibility, with mothers exposing the foetus to a milieu that perpetuates a stressed epigenotype. As the metabolic syndrome increases oxidative stress and reduces life expectancy, a better descriptor may therefore be the Lifestyle-Induced Metabolic Inflexibility and accelerated AGEing syndrome – LIMIT-AGE. As life expectancy in the Gulf begins to fall, with perhaps a third of this life being unhealthy – including premature loss of sexual function, it is vital to detect evidence of this condition as early in life as possible. One effective way to do this is by detecting evidence of metabolic inflexibility by studying body fat content and distribution by magnetic resonance (MR). The Gulf Metabolic Syndrome thus represents an accelerated form of the metabolic syndrome induced by the unprecedented rapidity of lifestyle change in the region, the stress of which is being passed from generation to generation and may be accumulative. The fundamental cause is probably due to a rapid increase in countrywide wealth. This has benefited most socioeconomic groups, resulting in the development of an obesogenic environment as the result of the rapid adoption of Western labour saving and stress relieving devices (e.g. cars and air conditioning), as well as the associated high calorie diet
A Comparative Study of the Short Term Cold Resistance Response in Distantly Related Drosophila Species: The Role of regucalcin and Frost
The molecular basis of short term cold resistance (indexed as chill-coma recovery time) has been mostly addressed in D. melanogaster, where candidate genes (Dca (also known as smp-30) and Frost (Fst)) have been identified. Nevertheless, in Drosophila, the ability to tolerate short term exposure to low temperatures evolved several times independently. Therefore, it is unclear whether variation in the same candidate genes is also responsible for short term cold resistance in distantly related Drosophila species. It should be noted that Dca is a candidate gene for cold resistance in the Sophophora subgenus only, since there is no orthologous gene copy in the Drosophila subgenus. Here we show that, in D. americana (Drosophila subgenus), there is a north-south gradient for a variant at the 5′ non-coding region of regucalcin (a Dca-like gene; in D. melanogaster the proteins encoded by the two genes share 71.9% amino acid identities) but in our D. americana F2 association experiment there is no association between this polymorphism and chill-coma recovery times. Moreover, we found no convincing evidence that this gene is up-regulated after cold shock in both D. americana and D. melanogaster. Size variation in the Fst PEST domain (putatively involved in rapid protein degradation) is observed when comparing distantly related Drosophila species, and is associated with short term cold resistance differences in D. americana. Nevertheless, this effect is likely through body size variation. Moreover, we show that, even at two hours after cold shock, when up-regulation of this gene is maximal in D. melanogaster (about 48 fold expression change), in D. americana this gene is only moderately up-regulated (about 3 fold expression change). Our work thus shows that there are important differences regarding the molecular basis of cold resistance in distantly related Drosophila species
Transgenerational Effects of Parental Larval Diet on Offspring Development Time, Adult Body Size and Pathogen Resistance in Drosophila melanogaster
Environmental conditions experienced by parents are increasingly recognized to affect offspring performance. We set out to investigate the effect of parental larval diet on offspring development time, adult body size and adult resistance to the bacterium Serratia marcescens in Drosophila melanogaster. Flies for the parental generation were raised on either poor or standard diet and then mated in the four possible sex-by-parental diet crosses. Females that were raised on poor food produced larger offspring than females that were raised on standard food. Furthermore, male progeny sired by fathers that were raised on poor food were larger than male progeny sired by males raised on standard food. Development times were shortest for offspring whose one parent (mother or the father) was raised on standard and the other parent on poor food and longest for offspring whose parents both were raised on poor food. No evidence for transgenerational effects of parental diet on offspring disease resistance was found. Although paternal effects have been previously demonstrated in D. melanogaster, no earlier studies have investigated male-mediated transgenerational effects of diet in this species. The results highlight the importance of not only considering the relative contribution each parental sex has on progeny performance but also the combined effects that the two sexes may have on offspring performance
СПІВВІДНОШЕННЯ ПОНЯТЬ «КЕРІВНИЦТВО» ТА «ЛІДЕРСТВО» В УПРАВЛІННІ СУЧАСНОЮ ОРГАНІЗАЦІЄЮ
Тhe article examines the relationship between the concepts of «guidance» and «leadership» in the management of a modern organization. It is determined that the micro-level of management is provided by such characteristics of subject-object management interaction as guidance and leadership. Guidance and leadership are products of internal organizational activity that provide management with performance and quality characteristics in the context of services provided. It was found out that guidance and leadership in the system of organizational interactions can complement each other or even transform into each other. Traditionally, in stable organizational forms, the manager is also a leader. This is largely due to the fact that the very status of a manager gives its bearer an advantage over other employees in terms of leadership positions. It is proved that guidance, leadership and leadership management, as a compilation of both social resources in the system of organizational interactions in Applied terms are important attributes for the implementation of the management process, which are currently a necessary condition for the professionalism of a modern manager. Досліджено співвідношення понять «керівництво» та «лідерство» в управлінні сучасною організацією. Визначено, що мікрорівень управління забезпечують такі характеристики суб’єкт-об’єктної управлінської взаємодії, як керівництво і лідерство. Керівництво і лідерство є продуктами внутрішньо організаційної діяльності, що надають управлінню характеристики ефективності та якості в контексті надаваних послуг. З’ясовано, що керівництво і лідерство в системі організаційних взаємодій можуть доповнювати один одного або навіть один в одного трансформуватися. Традиційно в стабільних організаційних формах керівник є в той же час і лідером. Багато в чому це обумовлено тим, що сам статус керівника дає його носію перевагу над іншими співробітниками щодо лідерських позицій. Доведено, що керівництво, лідерство та лідерське управління, як компіляція обох соціальних ресурсів в системі організаційних взаємодій у прикладному відношенні є важливими атрибутами для реалізації процесу управління, які в даний час є необхідною умовою професіоналізму сучасного керівника
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