12 research outputs found
Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses
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Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses
Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses
Demand for organic foods is partially driven by consumers' perceptions that they are more nutritious. However, scientific opinion is divided on whether there are significant nutritional differences between organic and non-organic foods, and two recent reviews have concluded that there are no differences. In the present study, we carried out meta-analyses based on 343 peer-reviewed publications that indicate statistically significant and meaningful differences in composition between organic and non-organic crops/crop-based foods. Most importantly, the concentrations of a range of antioxidants such as polyphenolics were found to be substantially higher in organic crops/crop-based foods, with those of phenolic acids, flavanones, stilbenes, flavones, flavonols and anthocyanins being an estimated 19 (95% CI 5, 33)%, 69 (95% CI 13, 125)%, 28 (95% CI 12, 44)%, 26 (95% CI 3, 48)%, 50 (95% CI 28, 72)% and 51 (95% CI 17, 86)% higher, respectively. Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies. Additionally, the frequency of occurrence of pesticide residues was found to be four times higher in conventional crops, which also contained significantly higher concentrations of the toxic metal Cd. Significant differences were also detected for some other (e.g. minerals and vitamins) compounds. There is evidence that higher antioxidant concentrations and lower Cd concentrations are linked to specific agronomic practices (e.g. non-use of mineral N and P fertilisers, respectively) prescribed in organic farming systems. In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production season
Light pollution - what do we know about its effect on human physiology?
Funkcjonowanie organizmu cz艂owieka i pozosta艂ych mieszka艅c贸w Ziemi dostosowuje si臋 do cyklicznych zmian 艣rodowiska, czyli naturalnych okres贸w 艣wiat艂a i ciemno艣ci (dzie艅 i noc) nast臋puj膮cych po sobie z niezmienn膮 regularno艣ci膮 i zawsze zamykaj膮cych si臋 w 24 godzinach doby. Rytmiczny przebieg proces贸w fizjologicznych generuje endogenny mechanizm molekularny, tzw. zegar biologiczny, wymagaj膮cy sta艂ej synchronizacji ze zmieniaj膮cymi si臋 warunkami zewn臋trznymi. Najwa偶niejszym sygna艂em 艣rodowiskowym, tzw. dawc膮 czasu, jest 艣wiat艂o odbierane przez specjalne receptory melanopsynowe siatk贸wki, sk膮d informacja jest kierowana do g艂贸wnego (centralnego) zegara mieszcz膮cego si臋 u ssak贸w w j膮drach nadskrzy偶owaniowych podwzg贸rza (SCN). Zegar SCN kontroluje procesy fizjologiczne i zachowanie, przekazuje te偶 informacj臋 do szyszynki, produkuj膮cej i uwalniaj膮cej do krwi melatonin臋, kt贸ra jako hormon ciemno艣ci odpowiednio modyfikuje funkcjonowanie narz膮d贸w docelowych. Zak艂贸cenie naturalnych cykli 艣wiat艂a i ciemno艣ci zar贸wno desynchronizuje prac臋 zegara, jak i zaburza naturalny rytm syntezy melatoniny, w istotny spos贸b wp艂ywaj膮c na funkcje ca艂ego organizmu. Coraz powszechniejsze ska偶enie 艣wiat艂em, czyli jego obecno艣膰 w niew艂a艣ciwym czasie i ilo艣ci, wydaje si臋 wi膮za膰 z ogromnym wzrostem zachorowa艅 na tzw. choroby cywilizacyjne oraz z post臋puj膮c膮 oporno艣ci膮 na tradycyjne 艣rodki terapeutyczne. W artykule s膮 om贸wione niekt贸re aspekty tego wp艂ywu na ludzi na podstawie dost臋pnych bada艅 populacyjnych.Diurnal rhythms and seasonal cycles operating in humans and other living organisms adjust their function to the sequence day/night, and allow to anticipate the next day sunrise. Generated by the endogenous molecular mechanism (i.e. biological clock), diurnal rhythms are synchronized with the actual external conditions by the environmental cues, with light being the most potent of them. Coordinating effect of light is exerted through the non-visual pathway starting in the melanopsin containing receptors of the retina and going to the master clock. Located in mammals in the suprachiasmaticus nucleus (SCN), master clock controls majority of downstream physiological processes and behavior. Information on the daily light cycle is sent also to the pineal gland, producing and releasing its main hormone melatonin as a biochemical substrate of darkness, perceived by the effector organs. Interruption of the natural circadian light-dark cycle desynchronizes functioning of the master clock and disrupts the normal melatonin rhythm, leading to the serious pathophysiological consequences. Increasing prevalence of the inappropriate presence of light, i.e. light pollution, adversely affects human physiology, and seems to be responsible for an important increase in several civilization-related illness and, even more dangerous, increased resistance to the conventional treatments. Present article discusses some aspects of the effect of light pollution based on the population studies
Melatonin: the hormone of sleep or darkness?
Funkcjonowanie organizm贸w zamieszkuj膮cych kul臋 ziemsk膮 odbywa si臋 pod dyktando zmian warunk贸w zewn臋trznych, wynikaj膮cych z ruchu obrotowego naszej planety (dzie艅 i noc) oraz jej obiegu wok贸艂 S艂o艅ca (pory roku). Wi臋kszo艣膰, a mo偶e wszystkie procesy fizjologiczne przebiegaj膮 ze zmiennym nasileniem w ci膮gu doby, kszta艂tuj膮c w ten spos贸b rytmy dobowe, zsynchronizowane ze zmianami zachodz膮cymi w otoczeniu. Rytmy generuje zegar endogenny, z g艂贸wnym oscylatorem oko艂odobowym zlokalizowanym u ssak贸w w j膮drach nadskrzy偶owaniowych podwzg贸rza (SCN), natomiast synchronizacja jego pracy z warunkami 艣rodowiskowymi wymaga czytelnych dla zegara sygna艂贸w zewn臋trznych, t艂umaczonych nast臋pnie na j臋zyk zrozumia艂y dla kom贸rek, tkanek i narz膮d贸w. Najsilniejszym "dawc膮 czasu" jest 艣wiat艂o, a struktur膮 odbieraj膮c膮 informacj臋 o 艣wietle i ciemno艣ci jest szyszynka, gruczo艂 neuroendokrynowy kr臋gowc贸w, w kt贸rym syntetyzowana jest melatonina, stanowi膮ca "biochemiczny substrat ciemno艣ci". Szyszynkowa synteza melatoniny przebiega rytmicznie w ci膮gu doby, z nasileniem w nocy i tylko 艣ladowymi ilo艣ciami powstaj膮cymi w dzie艅. Melatonina pe艂ni funkcj臋 zegara i kalendarza, bowiem czas jej syntezy zale偶y od sezonowo zmieniaj膮cej si臋 d艂ugo艣ci nocy, a niesiona przez ni膮 informacja jest odbierana nie tylko zwrotnie przez SCN, ale r贸wnie偶 przez wi臋kszo艣膰 narz膮d贸w, w kt贸rych moduluje przebieg proces贸w. Wszystkie warunki, kt贸re zaburzaj膮 nocn膮 syntez臋 melatoniny (np. loty transkontynentalne, praca zmianowa, niebiesko-fioletowe 艣wiat艂a LED generowane przez towarzysz膮ce cz艂owiekowi r贸偶ne urz膮dzenia elektroniczne) prowadz膮 do zaburzenia rytm贸w fizjologicznych ludzi, co wydaje si臋 by膰 przyczyn膮 wielu chor贸b tzw. cywilizacyjnych. Nale偶膮 do nich tak偶e zaburzenia snu, z kt贸rych pewne mog膮 by膰 korygowane przez egzogenn膮 melatonin臋 lub jej pochodne, cho膰 przy ich stosowaniu trzeba uwzgl臋dnia膰 og贸lnoustrojow膮 obecno艣膰 receptor贸w melatoniny, wp艂ywaj膮cej t膮 drog膮 moduluj膮co na funkcjonowanie wi臋kszo艣ci tkanek i narz膮d贸w.Terrestrial organisms are influenced by the cyclical nature of geophysical variations in the solar daylength and seasonal changes of the environmental day/night cycle. Adaptation to these changes includes regulation of the intensity of majority (all?) physiological processes generated by an endogenous mechanism known as the biological clock. In mammals, main biological (master) clock, is located in the suprachiasmatic nucleus (SCN) of the hypothalamus, and its periodicity is synchronized to 24 hs by the external cues, called time givers. Main synchronizing external factor is light/dark cycle, and in particular length of darkness, which is a period of elevated synthesis of melatonin, a neurohormone produced in the pineal gland, existing in all vertebrate species. As the duration of night vary according to the season, melatonin being a biochemical substrate of darkness acts within the body as "a clock and a calendar". Melatonin released to the circulation adjusts activity of SCN to the external lighting conditions and also modulates diurnal rhythmicity of several physiological processes. Various environmental conditions perturbing nocturnal rise of melatonin synthesis (e.g. transmeridian flights, shift work, blue-violet light emitted by several electronic devices equipped with LED) lead to the desynchronization of these circadian rhythms giving increased frequency of different illness appearing in the modern societies, including sleep disorders. Correction of this kind of disorders seems to be possible, at least partly, by the evening treatment with exogenous melatonin or its analogs. It is, however, necessary to keep in mind that melatonin action within the body is much more extended as its receptors are present in majority of organs and modulatory influence of melatonin on several physiological processes must be taken into consideration
Melatonin, multifunctional signal molecule in mammals: origin, functions, mechanisms of action
Methoxyindole hormone - melatonin (MEL) is produced and released by the mammalian pineal gland in a circadian rhythm exhibiting a low level during the day and an elevation at night, strictly dependent on the environmental lighting conditions. The main MEL function is, therefore, to synchronize diurnal rhythms of several physiological processes and for the diurnally active species (including humans) it gives information on the beginning of sleepiness. For the nocturnal species, however, elevated MEL level serves as a signal to start locomotor and feeding activity. In seasonal breeders the pineal gland function synchronizes the time of gonadal development and sexual activity with the external conditions in a way that progeny appears in the optimal climatic moment. MEL is produced also extrapineally, e.g. in the gastro-intestinal tract and bone marrow, where it exerts a protective effect due to its activity as an antioxidant and a potent free radical scavenger. Being both lipid and water soluble, MEL is able to cross biological barriers and, therefore, it uses several cellular mechanism to exert its physiological activity, including membrane and nuclear receptors, proteins of the cytoskeleton, mitochondrial membrane stabilization. MEL is also involved in immunomodulation, the effects are different and dependent on numerous factors, nevertheless, its immunostimulatory activity is generally well accepted. Additionally, activated immune cells are able to produce MEL acting in an auto- and paracrine way. As an efficient antioxidant MEL exerts the anti-inflammatory effect, which, reciprocally, modulates the pineal gland biosynthetic activity adapting it to temporary endogenous conditions.Szyszynka ssak贸w produkuje i wydziela do krwi melatonin臋 (MEL)
w rytmie dobowym, kt贸rego cech膮 charakterystyczn膮 jest wysoki poziom w nocy
niski w dzie艅, a czas nocnej syntezy zale偶y od warunk贸w 艣wietlnych otoczenia.
Dzi臋ki temu MEL synchronizuje wiele proces贸w fizjologicznych przebiegaj膮cych
rytmicznie, a jako chemiczny sygna艂 ciemno艣ci przekazuje gatunkom
o aktywno艣ci dziennej (w tym ludziom) informacj臋 o rozpocz臋ciu pory snu.
Gatunki aktywne w nocy inaczej interpretuj膮 sygna艂 melatoninowy. Dla zwierz膮t
rozmna偶aj膮cych si臋 sezonowo informacja niesiona przez MEL stanowi sygna艂 do
takiej synchronizacji funkcji rozrodczych z warunkami klimatycznymi, aby
potomstwo mog艂o pojawi膰 si臋 w optymalnym momencie. Melatonina powstaje
tak偶e pozaszyszynkowo, np. w uk艂adzie pokarmowym, gdzie pe艂ni funkcje
ochronne, zwi膮zane z aktywnym zmiataniem wolnych rodnik贸w i w艂a艣ciwo艣ciami
antyoksydacyjnymi. Jako cz膮steczka amfifilowa mo偶e przekracza膰 bariery
biologiczne, dlatego swoje efekty mo偶e wywiera膰 za po艣rednictwem wielu
r贸偶nych mechanizm贸w takich jak: wi膮zanie z receptorami b艂onowymi i j膮drowymi,
bia艂kami cytozolowymi, stabilizowanie b艂ony mitochondrialnej. MEL wykazuje
dzia艂anie immunomodulacyjne, zale偶ne od wielu czynnik贸w, cho膰 zasadniczo
wydaje si臋 by膰 czynnikiem wspomagaj膮cym odporno艣膰, a aktywowane kom贸rki
odporno艣ciowe tak偶e syntetyzuj膮 MEL dzia艂aj膮c膮 auto- i parakrynowo. Dzi臋ki
w艂a艣ciwo艣ciom antyoksydacyjnym pe艂ni istotn膮 rol臋 przeciwzapaln膮, z kolei
tocz膮cy si臋 proces zapalny moduluje aktywno艣膰 biosyntetyczn膮 szyszynki,
dostosowuj膮c je do aktualnych warunk贸w w organizmie
Tribute to bursa of Fabicius - what is the modern immunology' debt to the birds?
Wiele odkry膰, fundamentalnych dla rozwoju biologii XX w., dokona艂o si臋 dzi臋ki badaniom prowadzonym na ptakach. W艣r贸d nich nale偶y wymieni膰 opracowanie przez Ludwika Pasteura podstaw i praktycznego stosowania szczepionek oraz wskazanie przez Bruce'a Glicka roli bursy Fabrycjusza, istotnej dla zrozumienia podstawowych mechanizm贸w odporno艣ciowych. Zw艂aszcza poznanie funkcjonalnej dychotomii uk艂adu odporno艣ciowego ptak贸w, u kt贸rych bursa Fabrycjusza stanowi centralne miejsce dojrzewania limfocyt贸w odpowiedzialnych za produkcj臋 przeciwcia艂, sk艂oni艂o uczonych do poszukiwania u ssak贸w odpowiednika bursy Fabrycjusza. Dzi臋ki tym odkryciom nowoczesna immunologia mog艂a zacz膮膰 sw贸j dynamiczny rozw贸j, pos艂uguj膮c si臋 najnowszymi metodami biologii molekularnej. A bursa Fabrycjusza nadal przyci膮ga zainteresowanie wielu badaczy, wykrywaj膮cych liczne peptydy pochodzenia bursalnego wywieraj膮ce efekty regulacyjne nie tylko w uk艂adzie odporno艣ciowym ptak贸w, lecz tak偶e o szerszym dzia艂aniu biologicznym, w odniesieniu do proces贸w odporno艣ciowych ssak贸w, nowotworzenia czy dzia艂ania antyoksydacyjnego. Cechy anatomiczne uk艂adu odporno艣ciowego kury domowej, takie jak brak w臋z艂贸w ch艂onnych, eozynofili czy limfocyt贸w rezyduj膮cych mog膮 wskazywa膰 na prostot臋 jego budowy. Dodatkowo zsekwencjonowanie genomu kury domowej pokaza艂o, 偶e u ptak贸w wiele proces贸w odporno艣ciowych mo偶e si臋 odbywa膰 przy bardziej oszcz臋dnym repertuarze cytokin, chemokin, receptor贸w i cz膮steczek kostymuluj膮cych ni偶 ten, kt贸ry wyst臋puje u ssak贸w. Jednak to uproszczenie jest tylko pozorne, poniewa偶 uk艂ad odporno艣ciowy ptak贸w spe艂nia w艂a艣ciwie wszystkie funkcje jakie spe艂nia uk艂ad odporno艣ciowy ssak贸w.Attribution by Bruce Glick in the fifties/sixties of twenty century an essential role of the bursa of Fabricius in the differentiation of a particular lymphocyte population in the chicken was a milestone in the modern immunology development. Incoming studies on both avian and mammalian experimental models were able to prove a functional dissociation of the humoral and cell-mediated immune response and to demonstrate that the bursa of Fabricius plays an important role in antibody production. Subsequently, the research was oriented towards the identification of the mammalian "bursa-equivalent" where the antibody-producing lymphocytes, named B-cells in the honor to the bursa of Fabricius, should be generated. Finally, this role in mammals has been proven for the embryonic liver and for the bone marrow lymphopoiesis in the postnatal life. Apart from that, bursa of Fabricius is an endocrine organ producing several peptides exhibiting immunoregulatory activity, not only towards the avian immune functions but also influencing mammalian immunity, both in vivo and in vitro. The most important among them seem to be: bursin (tripeptide discovered as the first bursal peptide), BASP (bursal anti-steroidogenic peptide, exerting and inhibitory effect on the steroid hormone synthesis in the ovarian follicles and adrenal cortex) and bursopentin (BP5, a peptide with an antioxidative properties). The anatomical features of the domestic chicken immune system, such as lack of lymph nodes, eosinophils or resident lymphocytes, may indicate the simplicity of its organization. In addition, the sequencing of the domestic chicken genome has shown that many immune processes in birds may occur with a more scant repertoire of cytokines, chemokines, receptors and costimulatory molecules than those found in mammals. However, this simplification is only apparent because the avian immune system fulfills all the functions as those of the mammalian one
Intracellular second messengers involved in melatonin signal transduction in chicken splenocytes in vitro
Changes in behaviour and in the circadian rhythms of melatonin and corticosterone in rats subjected to a forced-swimming test
Feed composition differences resulting from organic and conventional farming practices affect physiological parameters in Wistar rats - results from a factorial, two-generation dietary intervention trial
Recent human cohort studies reported positive associations between organic food consumption and a lower incidence of obesity, cancer, and several other diseases. However, there are very few animal and human dietary intervention studies that provide supporting evidence or a mechanistic understanding of these associations. Here we report results from a two-generation, dietary intervention study with male Wistar rats to identify the effects of feeds made from organic and conventional crops on growth, hormonal, and immune system parameters that are known to affect the risk of a number of chronic, non-communicable diseases in animals and humans. A 2 × 2 factorial design was used to separate the effects of contrasting crop protection methods (use or non-use of synthetic chemical pesticides) and fertilizers (mineral nitrogen, phosphorus and potassium (NPK) fertilizers vs. manure use) applied in conventional and organic crop production. Conventional, pesticide-based crop protection resulted in significantly lower fiber, polyphenol, flavonoid, and lutein, but higher lipid, aldicarb, and diquat concentrations in animal feeds. Conventional, mineral NPK-based fertilization resulted in significantly lower polyphenol, but higher cadmium and protein concentrations in feeds. Feed composition differences resulting from the use of pesticides and/or mineral NPK-fertilizer had a significant effect on feed intake, weight gain, plasma hormone, and immunoglobulin concentrations, and lymphocyte proliferation in both generations of rats and in the second generation also on the body weight at weaning. Results suggest that relatively small changes in dietary intakes of (a) protein, lipids, and fiber, (b) toxic and/or endocrine-disrupting pesticides and metals, and (c) polyphenols and other antioxidants (resulting from pesticide and/or mineral NPK-fertilizer use) had complex and often interactive effects on endocrine, immune systems and growth parameters in rats. However, the physiological responses to contrasting feed composition/intake profiles differed substantially between the first and second generations of rats. This may indicate epigenetic programming and/or the generation of “adaptive” phenotypes and should be investigated further