
Pawel Marek MajewskiUniversity of Warsaw | UW · Institute of Experimental Zoology
Pawel Marek Majewski
Doctor of Philosophy
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36
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Introduction
Pawel Marek Majewski currently works at the Faculty of Biology, University of Warsaw. Pawel does research in Physiology and Biology. Their most recent publication is 'Daily profiles of melatonin synthesis-related indoles in the pineal glands of young chickens (Gallus gallus domesticus L.)'.
Additional affiliations
December 2007 - November 2009
October 2004 - present
Education
October 1994 - June 1999
Publications
Publications (36)
Our recent research on the pineal gland of young chickens confirmed that three genes encoding enzymes involved in pineal melatonin biosynthesis,tryptophan hydroxylase 1 (Tph1),arylalkylamine-N-acetyltransferase (Aanat) and acetylserotonin O-methyltransferase (Asmt),are transcribed rhythmically under light:dark (L:D) 12:12 conditions in vivo. Additi...
Previously, we have demonstrated that the timing of the nocturnal peak of activity of the pineal arylalkylamine-N-acetyltransferase - a key enzyme in the melatonin biosynthesis pathway - in 3-wk-old chickens kept from the day of hatch under controlled laboratory conditions (L:D 12:12) varies depending on the season of hatch (summer vs. winter). The...
Previously, we have demonstrated the postembryonic development of chicken (Gallus gallus domesticus L.) pineal gland functions expressed as changes in melatonin (MEL) biosynthesis. Pineal concentrations of MEL and its precursor serotonin (5-HT) were shown to increase between the 2nd and 16th day of life. We also found that levels of the mRNAs encod...
Previously, we demonstrated that experimental peritonitis in chickens was attenuated by treatment with exogenous melatonin, while the developing inflammation decreased pineal AANAT activity. This suggested the existence of a bidirectional relationship between the activated immune system and pineal gland function. The aim of the present study was to...
Reduced bone mass is a common complication in chronic inflammatory diseases, although the mechanisms are not completely understood.
The PHEX gene encodes a zinc endopeptidase expressed in osteoblasts and contributes to bone mineralization. The aim of this
study was to determine the molecular mechanism involved in TNF-mediated down-regulation of Phe...
Relapsing-remitting multiple sclerosis is associated with changes in Jak/STAT pathways in immune cells, but the influence of disease-modifying drugs on these pathways is poorly understood. The aim of this study was to evaluate the impact of first-line disease-modifying drugs used in treatment of RRMS on expression of the STAT pathway and T-cell-rel...
Introduction
Campylobacter are the most common cause of food poisoning, which manifests itself in diarrhoea of varying severity. Additionally, because of the increasing number of people with immune deficiencies, more frequent serious complications of Campylobacter infections are being observed. The main source of infection is the consumption of con...
The pineal gland, one of the three equivalent avian biological clock structures, is also the site of intensive neurosteroid synthesis (7α-hydroxypregnenolone and allopregnanolone). Pineal neurosteroid biosynthesis involves six enzymes: cytochrome P450 side-chain cleavage - Cyp11a1 encoded, cytochrome P4507α - Cyp7b1, 3β-hydroxysteroid dehydrogenase...
The avian pineal gland is one of three central biological clocks that contain all the components of a circadian system: a photoreceptive input, oscillator, and rhythmically secreted melatonin (MEL) as an effector. The biosynthesis of MEL is regulated by the neurotransmitters noradrenaline (NA), vasoactive intestinal peptide (VIP), and pituitary ade...
Although loss of bone mineral density is a common symptom of chronic inflammatory diseases, its mechanisms are still poorly understood. The PHEX gene encodes a Zn-endopeptidase expressed in osteoblasts and contributes to bone mineralization. Data derived from rodents has indicated co-repression of the PHEX gene by the NF-κB pathway and poly(ADP-rib...
The aim of the present study was to characterize the daily profiles of melatonin synthesis-related indoles in the pineal glands of male Hy-Line chickens hatched in the winter and reared under controlled light (L:D 12:12) conditions. The pineal glands were isolated from 16-day-old birds immediately after decapitation every 2 h over a 24-h period. Th...
Biological rhythms in birds are driven by the master clock, which includes the suprachiasmatic nucleus, the pineal gland and the retina. Light/dark cycles are the cues that synchronize the rhythmic changes in physiological processes, including immunity. This review summarizes our investigations on the bidirectional relationships between the chicken...
Campylobacter jejuni is the most frequent cause of human food-borne gastroenteritis and chicken meat is the main source of infection. Recent studies showed that broiler chicken immunization against Campylobacter should be the most efficient way to lower the number of human infections by this pathogen. Induction of the mucosal immune system after or...
Seasonality of immunity in birds has been confirmed, but underlying mechanisms are still not fully explained. Present study was undertaken to verify hypothesis on the role of melatonin in the season-related development of inflammation in chickens. Chickens hatched in summer and winter were kept for 12 days in the season-corresponding LD conditions...
The avian pineal gland, apart from the hypothalamic master clock (suprachiasmatic nuclei, SCN) and retina, functions as an independent circadian oscillator, receiving external photic cues that it translates into the rhythmical synthesis of melatonin, a biochemical signal of darkness. Functional similarity to the mammalian SCN makes the avian pineal...
CT. The aim of this study was to examine the involvement of me-latonin in the photoperiod-related development of inflammation in chickens. Newly hatched birds obtained in summer and winter were kept in a light : dark (LD) cycle (corresponding to the season of hatch) or in continuous light (LL). Half of the chickens held under LL conditions were giv...
Immune system activity in higher vertebrates (mammals and birds) varies over the year, mainly in correlation with the external light phase duration and intensity, as well as accompanying environmental cues. Light influences immunity mainly via retina-SCN-pineal gland-melatonin pathway. Diurnal rhythm of melatonin biosynthesis, adjusted to the chang...
Campylobacter jejuni is a major food-borne pathogen, causing gastroenteritis worldwide. Chickens are considered to be one of the most common sources of human C. jejuni infection in developed countries. Campylobacter CjaD/Pal protein (annotated as Cj0113 in C. jejuni strain NCTC11168) is a highly immunogenic, membrane-located antigen, conserved amon...
Primary exposure of mice to the nematode Heligmosomoides polygyrus infection reduces inflammation in an experimental model of colitis. The aim of the present investigation was to evaluate whether the reduced inflammation provoked by H. polygyrus L4 larvae in BALB/c mice treated with dextran sulphate sodium is associated with changed expression of o...
The Dsb family of redox proteins catalyzes disulfide bond formation and isomerization. Since mutations indsb genes change the conformation and stability of many extracytoplasmic proteins, and since many virulence factors of pathogenic bacteria are extracytoplasmic, inactivation ofdsb genes often results in pathogen attenuation. This study investiga...
Reduced bone mass is a common complication in chronic inflammatory diseases, although the mechanisms are not completely understood. Phex gene encodes an osteoblast Zn‐endopeptidase controlling bone mineralization and is inhibited by TNF in chemically‐induced colitis. Here, we confirm its downregulation in CD4 ⁺ CD45RB high T‐cell transfer colitis,...
Klotho (Kl) deficiency leads to premature senescence and impaired Ca ²⁺ /P i homeostasis. Since osteopenia/osteoporosis are fequently associated with human IBD, we investigated the changes in Klotho gene expression as a consequence of experimental colitis. We utilized three models: TNBS colitis, microflora‐induced colitis in germ‐free IL‐10 −/− mic...
Influence of the season of hatch on the functional characteristics of the pineal gland was examined in neonatal Hi-Line male chickens. The pineal glands from 2-day-old birds hatched in summer and winter, and kept from the day of hatch in artificial lighting conditions (12L:12D), were isolated under dim red light in the middle of the day or night. T...
Klotho (KL) is an anti-inflammatory protein that protects the endothelium from nitric oxide (NO)-induced dysfunction, reduces the expression of endothelial adhesion molecules, and potentially regulates T-cell functions. KL deficiency leads to premature senescence and impaired Ca2+/Pi homeostasis, which can lead to inflammatory bowel disease (IBD)-a...
Reduced bone mass is a common complication in inflammatory bowel diseases, although
the mechanisms contributing to osteopenia are not completely understood. The PHEX
gene encodes a Zn-endopeptidase expressed primarily in osteoblasts and odontoblasts. It
participates in systemic phosphate homeostasis, vitamin D metabolism, and bone mineralization.
O...
Previously we have demonstrated that in Siberian hamsters some immune measures, especially the development of experimentally evoked peritonitis, varied in a photoperiod- and gender-dependent manner. The aim of the present study was to investigate whether the photoperiod-related differences in the activity of inflammation-involved immune cells are i...
Melatonin, a multifunctional neurohormone synthesized and secreted by the pineal
gland in circadian manner with an elevation during darkness, acts for an organism
as a source of information on external lighting conditions. In non-mammalian
vertebrates including birds the pineal gland plays an important role as one of the
oscillators of the circadia...
The presence of melatonin and the enzymes (transcripts and activities) involved in its synthesis, i.e. arylalkylamine N-acetyltransferase (AA-NAT) and hydroxyindole-O-methyltransferase (HIOMT), was investigated in the eggs and early embryos of Japanese quail at Hamburger-Hamilton stages 1-10. Melatonin was present in the egg yolk (approximately 70...
The immunomodulatory action of melatonin in different animal species is already well known, although the mechanism(s) by which the indoleamine influences the immune system have yet to be fully elucidated. Previously, we have shown both anti-inflammatory and opioid-mediated influence of exogenous melatonin on thioglycollate-induced peritonitis in yo...
Tea tree oil (TTO) is well known as an anti-microbial and immunomodulatory agent and the latterproperty was examined in this study. Male, C57BI10 x CBA/H (F1), mice were exposed to TTO vapourthree times a day, for one week. During this period, half of the mice also received naltrexone (endogenousopioid receptor antagonist) in their drinking water....
The immunomodulatory properties of melatonin (Mel) are generally recognized but the mechanisms of its action are not fully understood. In mammals, some of the immunomodulatory effects of Mel are mediated by opioids synthesized by immune cells under its influence. The present study was performed to examine whether Mel-induced opioids are involved in...
Siberian hamsters are photoperiodic animals exhibiting seasonality of reproduction and other physiological functions. Thus, the influence of photoperiod on the in vitro activity of selected immune cells from male and female hamsters challenged with peritoneal inflammation was examined.
Animals were housed for 8-10 weeks in LD (L:D=18:6) or SD (L:D=...
The pineal gland is a vertebrate neuroendocrine organ converting environmental photoperiodic information into a biochemical message (melatonin) that subsequently regulates the activity of numerous target tissues after its release into the bloodstream. A phylogenetically conserved feature is increased melatonin synthesis during darkness, even though...
Morphine exerts immunomodulatory effects dependent on several factors including species and parameter examined. The aim of this study was to assess the influence of morphine on experimental peritonitis and leukocyte activity in young chickens of both sexes.
Peritonitis was elicited by intraperitoneal injection of thioglycollate (TG) alone or supple...