Membrane fatty acid composition and longevity of mammals and birds

The fatty acid composition of membrane lipids varies systematically among species in a manner that is consistent with their metabolic rate and longevity. Because the susceptibility of fatty acids to peroxidation relates directly to their extent of unsaturation, it is possible to calculate a peroxidation index (PI) for membranes through characterization of their specific fatty acid composition. Long-living mammals and birds have membrane lipids with a lower PI than shorter-living species. Bird and mammal species with the same maximum life span also have membrane lipids with essentially the same PI. Exceptionally long-living mammals and birds usually have membrane lipids high in monounsaturates, but low in polyunsaturates, with the consequence that the PI of their membrane lipids is as low as expected for their respective longevity. Longevity variation within species (whether due to calorie-restriction, extended longevity associated with specific strains, queen-worker differences in honey bees or inherited longevity differences among humans) is also associated with differences in membrane composition and PI. Membrane composition is specific for each species and PI appears to generally be resistant to dietary manipulation. It is postulated that membrane fatty acid composition is an important influence on aging and the determination of maximum life span

Hetero-cycloreversions Mediated by Photoinduced Electron Transfer

[EN] Discovered more than eight decades ago, the Diels-Alder (DA) cycloaddition (CA) remains one of the most versatile tools in synthetic organic chemistry. Hetero-DA processes are powerful methods for the synthesis of densely functionalized six-membered heterocycles, ubiquitous substructures found in natural products and bioactive compounds. These reactions frequently employ azadienes and oxadienes, but only a few groups have reported DA processes with thiadienes. The electron transfer (ET) version of the DA reaction, though less investigated, has emerged as a subject of increasing interest. In the last two decades, researchers have paid closer attention to radical ionic hetero-cycloreversions, mainly in connection with their possible involvement in the repair of pyrimidine(6-4)pyrimidone photolesions in DNA by photolyases. In biological systems, these reactions likely occur through a reductive photosensitization mechanism. In addition, photooxidation can lead to cycloreversion (CR) reactions, and researchers can exploit this strategy for DNA repair therapies. In this Account, we discuss electron-transfer (ET) mediated hetero-CR reactions. We focus on the oxidative and reductive ET splitting of oxetanes, azetidines, and thietanes. Photoinduced electron transfer facilitates the splitting of a variety of four-membered heterocycles. In this context, researchers have commonly examined oxetanes, both experimentally and theoretically. Although a few studies have reported the cycloreversion of azetidines and thietanes carried out under electron transfer conditions, the number of examples remains limited. In general, the cleavage of the ionized four-membered rings appears to occur via a nonconcerted two-step mechanism. The trapping of the intermediate 1,4-radical ions and transient absorption spectroscopy data support this hypothesis, and it explains the observed loss of stereochemistry in the products. In the initial step, either C-C or C-X bond breaking may occur, and the preferred route depends on the substitution pattern of the ring, the type of heteroatom, and various experimental conditions. To better accommodate spin and charge, C-X cleavage happens more frequently, especially in the radical anionic version of the reaction. The addition or withdrawal of a single electron provides a new complementary synthetic strategy to activate hetero-cycloreversions. Despite its potential, this strategy remains largely unexplored. However, it offers a useful method to achieve C=X/olefin metathesis or, upon ring expansion, to construct six-membered heterocyclic rings.Financial support from the Spanish Government (Grants CTQ2010-14882, SEV2012-0267, and JCI-2010-06204) and the Generalitat Valenciana (Prometeo II/2013/005) is gratefully acknowledged.Pérez Ruiz, R.; Jiménez Molero, MC.; Miranda Alonso, MÁ. (2014). Hetero-cycloreversions Mediated by Photoinduced Electron Transfer. Accounts of Chemical Research. 47(4):1359-1368. https://doi.org/10.1021/ar4003224S1359136847

The Long Life of Birds: The Rat-Pigeon Comparison Revisited

The most studied comparison of aging and maximum lifespan potential (MLSP) among endotherms involves the 7-fold longevity difference between rats (MLSP 5y) and pigeons (MLSP 35y). A widely accepted theory explaining MLSP differences between species is the oxidative stress theory, which purports that reactive oxygen species (ROS) produced during mitochondrial respiration damage bio-molecules and eventually lead to the breakdown of regulatory systems and consequent death. Previous rat-pigeon studies compared only aspects of the oxidative stress theory and most concluded that the lower mitochondrial superoxide production of pigeons compared to rats was responsible for their much greater longevity. This conclusion is based mainly on data from one tissue (the heart) using one mitochondrial substrate (succinate). Studies on heart mitochondria using pyruvate as a mitochondrial substrate gave contradictory results. We believe the conclusion that birds produce less mitochondrial superoxide than mammals is unwarranted

Using of surveying-geological documentation of abandoned mines for practical solutions

Prawo geologiczne i górnicze nakłada na Prezesa Wyższego Urzędu Górniczego obowiązek gromadzenia i archiwizacji dokumentacji mierniczo-geologicznej zlikwidowanych zakładów górniczych. Czynności z tym związane wykonuje Archiwum Dokumentacji Mierniczo-Geologicznej w WUG. Archiwum udostępnia dokumentację zainteresowanym osobom i stronom dla potrzeb związanych z realizacją szeregu zadań z zakresu planowania przestrzennego i budownictwa, bezpieczeństwa powszechnego, ochrony środowiska oraz dochodzenia roszczeń z tytułu szkód pochodzenia górniczego. Zawarte w dokumentacji archiwalnej dane oraz informacje znajdują wykorzystanie praktyczne w wielu rozwiązaniach projektowych realizowanych w zakładach górniczych oraz w przedsięwzięciach proekologicznych na terenach pogórniczych.Geological and Mining Law lays on the President of State Mining Authority (WUG) an obligation of gathering and archivization of surveying-geological documentation of abandoned mines. The obligation is realized by Record Office of Surveying-Geological, which is the unit of WUG. The Office renders the documentation accessible persons or parties for purposes of realization of many goals in the field of: land use planning, public safety; environmental protection; and claiming damages connected to mining. Data and information contained in the documentation are practically used for a lot of planning solutions at mines as well as ecological projects in the post-mining lands

Problemy w diagnostyce pacjentów otyłych za pomocą rezonansu magnetycznego

W literaturze coraz częściej można znaleźć doniesienia zwracające uwagę na problemy w diagnostyce obrazowej wynikające z nadwagi pacjentów oraz związanych z tym faktem rozmiarami ciała. 2 listopada 2012 r. portal internetowy „gazeta.pl” w artykule: „Wielka Brytania: Brak skanerów MRI (Magnetic Resonance Imaging) dla chorobliwie otyłych. Będą badani sprzętem używanym w zoo?”, cytując za brytyjskim „The Telegraph” opublikował szokującą informację: „Brytyjskie szpitale będą zmuszone używać skanerów MRI z ogrodów zoologicznych, ponieważ standardowe urządzenia nie są w stanie poradzić sobie z pacjentami z poważną nadwagą (…)” [1]. Powstały przy współpracy z instytutem badawczym MillwardBrown, a prezentowany na stronie internetowej serwisu PotrafiszSchudnac.pl „Raport. Bieżące statystyki otyłości i nadwagi w Polsce na podstawie interaktywnej mapy otyłości Polski”, podając stan na drugie półrocze 2015 r. oszacował, że 49,55% Polaków ma nadwagę lub jest otyłych, w tym: 36,94% – to osoby z nadwagą, a 12,61% – z otyłością. Z raportu wynika, że niemal co drugi Polak ma nadwagę lub jest otyły, przy czym w województwach zachodnich jest więcej takich osób niż we wschodnich. Województwo śląskie znalazło się w tym rankingu na dziesiątym miejscu z odsetkiem 50,68% osób z nadwagą i otyłych [2, 3]. 16 marca 2016 r. „Puls Medycyny” opublikował artykuł pt. „Polacy ważą coraz więcej”, którego autorka, powołując się na źródła danych Głównego Urzędu Statystycznego GUS i Urzędu Statystycznego Unii Europejskiej EUROSTAT, podała, że 46% kobiet i 64% mężczyzn w Polsce choruje na nadwagę i otyłość, informując jednocześnie, że stawia to nas w pierwszej dziesiątce najbardziej otyłych narodów Europy [4]. Znany jest fakt, iż nadmierna otyłość może utrudniać poprawną i dokładną diagnostykę pacjenta. Otrzymane wyniki badań pacjentów o dużych rozmiarach charakteryzują się obniżoną jakością otrzymywanych obrazów (mniejszy SNR – Signal-to-Noise Ratio). Niektórzy badacze zwracają także uwagę na problem wpływu otyłości nie tylko w rezonansie magnetycznym, ale również w innych badaniach obrazowych: ultrasonografii, mammografii, radiografii i fluoroskopii, radiologii interwencyjnej, medycynie nuklearnej i pozytronowej emisyjnej tomografii komputerowej PET, praz CT [4, 5, 6]

The Influence of Gender and Year of Study on Stress Levels and Coping Strategies among Polish Dental

Background and objectives: Stress is a common term used to describe various adverse psychological conditions. Students in the dentistry field face many negative psychological outcomes. The core factors for stress among dental students are related to their training course and social contacts with peers. This research aimed to assess the stress of dental students depending on their gender and study year. Materials and methods: We used the Perceived Stress Scale (PSS-10) and Mini-COPE questionnaire. The surveys were conducted among 446 dental students (320 women and 126 men) at the Faculty of Medical Sciences of the Medical University of Silesia in Katowice. Results: For the second-year and fifth-year students, the differences in scores were statistically significant, while in both cases, men had significantly lower values on the analysed scale. The results of the Kruskal-Wallis test indicated significantly lower values on the PSS-10 scale for the third-year and fourth-year students than in first-year students. The performed statistical analysis of the data obtained from the Mini-COPE questionnaire showed significant differences between men and women in individual years of study. In the first year, women chose more often the strategies related to turning to religion (p = 0.007), seeking emotional support (p = 0.046), seeking instrumental support (p = 0.045) and dealing with something else (p = 0.029) in coping with stress than men. Conclusions: The highest level of stress was found among first-year dental students. Moreover, women were characterised with higher stress levels than men. Men more often use psychoactive substances and resort to a sense of humour to cope with stress. On the other hand, women turn to religion, seek instrumental and emotional support

Mitochondrial Acclimation Capacities to Ocean Warming and Acidification Are Limited in the Antarctic Nototheniid Fish, Notothenia rossii and Lepidonotothen squamifrons

Antarctic notothenioid fish are characterized by their evolutionary adaptation to the cold, thermostable Southern Ocean, which is associated with unique physiological adaptations to withstand the cold and reduce energetic requirements but also entails limited compensation capacities to environmental change. This study compares the capacities of mitochondrial acclimation to ocean warming and acidification between the Antarctic nototheniid Notothenia rossii and the sub-Antarctic Lepidonotothen squamifrons, which share a similar ecology, but different habitat temperatures. After acclimation of L. squamifrons to 9°C and N. rossii to 7°C (normocapnic/hypercapnic, 0.2 kPa CO2/2000 ppm CO2) for 4-6 weeks, we compared the capacities of their mitochondrial respiratory complexes I (CI) and II (CII), their P/O ratios (phosphorylation efficiency), proton leak capacities and mitochondrial membrane fatty acid compositions. Our results reveal reduced CII respiration rates in warm-acclimated L. squamifrons and cold hypercapnia-acclimated N. rossii. Generally, L. squamifrons displayed a greater ability to increase CI contribution during acute warming and after warm-acclimation than N. rossii. Membrane unsaturation was not altered by warm or hypercapnia-acclimation in both species, but membrane fatty acids of warm-acclimated L. squamifrons were less saturated than in warm normocapnia-/hypercapnia-acclimated N. rossii. Proton leak capacities were not affected by warm or hypercapnia-acclimation of N. rossii. We conclude that an acclimatory response of mitochondrial capacities may include higher thermal plasticity of CI supported by enhanced utilization of anaplerotic substrates (via oxidative decarboxylation reactions) feeding into the citrate cycle. L. squamifrons possesses higher relative CI plasticities than N. rossii, which may facilitate the usage of energy efficient NADH-related substrates under conditions of elevated energy demand, possibly induced by ocean warming and acidification. The observed adjustments of electron transport system complexes with a higher flux through CI under warming and acidification suggest a metabolic acclimation potential of the sub-Antarctic L. squamifrons, but only limited acclimation capacities for N. rossii