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1.
William R. Scott Cigdem Gelegen Keval Chandarana Efthimia Karra Ahmed Yousseif Chloé Amouyal Agharul I. Choudhury Fabrizio Andreelli Dominic J. Withers Rachel L. Batterham 《PloS one》2013,8(3)
Background
Neuronatin (NNAT) is an endoplasmic reticulum proteolipid implicated in intracellular signalling. Nnat is highly-expressed in the hypothalamus, where it is acutely regulated by nutrients and leptin. Nnat pre-mRNA is differentially spliced to create Nnat-α and -β isoforms. Genetic variation of NNAT is associated with severe obesity. Currently, little is known about the long-term regulation of Nnat.Methods
Expression of Nnat isoforms were examined in the hypothalamus of mice in response to acute fast/feed, chronic caloric restriction, diet-induced obesity and modified gastric bypass surgery. Nnat expression was assessed in the central nervous system and gastrointestinal tissues. RTqPCR was used to determine isoform-specific expression of Nnat mRNA.Results
Hypothalamic expression of both Nnat isoforms was comparably decreased by overnight and 24-h fasting. Nnat expression was unaltered in diet-induced obesity, or subsequent switch to a calorie restricted diet. Nnat isoforms showed differential expression in the hypothalamus but not brainstem after bypass surgery. Hypothalamic Nnat-β expression was significantly reduced after bypass compared with sham surgery (P = 0.003), and was positively correlated with post-operative weight-loss (R2 = 0.38, P = 0.01). In contrast, Nnat-α expression was not suppressed after bypass surgery (P = 0.19), and expression did not correlate with reduction in weight after surgery (R2 = 0.06, P = 0.34). Hypothalamic expression of Nnat-β correlated weakly with circulating leptin, but neither isoform correlated with fasting gut hormone levels post- surgery. Nnat expression was detected in brainstem, brown-adipose tissue, stomach and small intestine.Conclusions
Nnat expression in hypothalamus is regulated by short-term nutrient availability, but unaltered by diet-induced obesity or calorie restriction. While Nnat isoforms in the hypothalamus are co-ordinately regulated by acute nutrient supply, after modified gastric bypass surgery Nnat isoforms show differential expression. These results raise the possibility that in the radically altered nutrient and hormonal milieu created by bypass surgery, resultant differential splicing of Nnat pre-mRNA may contribute to weight-loss. 相似文献2.
Konstantinos Feidantsis Efthimia Antonopoulou Antigone Lazou Hans O. Pörtner Basile Michaelidis 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2013,183(5):625-639
The present study aimed to investigate the seasonal cellular stress response in vital organs, like the heart, the liver, the whole blood and the skeletal (red and white) muscles of the Mediterranean fish Sparus aurata during a 1-year acclimatization period in the field, in two examined depths (0–2 m and 10–12 m). Processes studied included heat shock protein expression and protein kinase activation. Molecular responses were addressed through the expression of Hsp70 and Hsp90, the phosphorylation of stress-activated protein kinases and particularly p38 mitogen-activated protein kinase (p38 MAPK), the extracellular signal-regulated kinases (ERK-1/2) and c-Jun N-terminal kinases (JNK1/2/3). The induction of Hsp70 and Hsp90 and the phosphorylation of p38 MAPK, JNKs and ERKs in the examined five tissues of the gilthead sea bream indicated a cellular stress response under the prism of a seasonal pattern which was characterized by distinct tissue specificity. Specifically, Hsp induction and MAPK activation occurred before peak summer water temperatures, with no further increases in their levels despite increases in water temperatures. Moreover, although water temperature did not vary significantly with depth of immersion, significant effects of depth on cellular stress response were observed, probably caused by different light regime. The expression and the activation of these certain proteins can be used as tools to define the extreme thermal limits of the gilthead sea bream. 相似文献
3.
The genome sequence analysis of Thermus thermophilus HB27, a microorganism with high biotechnological potential, has recently been published. In that report, the chromosomal
and the megaplasmid sequence were compared to those of other organisms and discussed on the basis of their physiological and
metabolic features. Out of the 2,218 putative genes identified through the large genome sequencing project, a significant
number has potential interest for biotechnology. The present communication will discuss the accumulating information on molecules
participating in fundamental biological processes or having potential biotechnological importance. 相似文献
4.
Antonopoulou S Tsoupras A Baltas G Kotsifaki H Mantzavinos Z Demopoulos CA 《Mediators of inflammation》2003,12(4):221-227
Periodontal diseases are localized chronic inflammatory conditions of the gingival and underlying bone and connective tissue. Platelet-activating factor (PAF), a potent inflammatory phospholipid mediator that has been previously detected in elevated levels in inflamed gingival tissues, in gingival crevicular fluid and in saliva, is implicated in periodontal disease. Our results from previous studies showed that the biologically active phospholipid detected in gingival crevicular fluid is a hydroxyl-PAF analogue. In this study, hydroxyl-PAF analogue was detected for the first time in human blood derived from patients with chronic periodontitis as well as from periodontally healthy volunteers. The hydroxyl-PAF analogue was purified by high-performance liquid chromatography, detected by biological assays and identified by electrospray analysis. In addition, the quantitative determination of PAF and hydroxyl-PAF analogue (expressed as PAF-like activity) showed a statistically significant increase in the ratio of hydroxyl-PAF analogue levels to PAF levels in periodontal patients, suggesting that this bioactive lipid may play a role in oral inflammation. 相似文献
5.
Protonotariou E Rizos D Malamitsi-Puchner A Moira E Sarandakou A Salamalekis E 《Mediators of inflammation》2003,12(3):185-188
BACKGROUND: In contrast to cellular receptors, soluble receptors do not enhance the cellular activation because they do not have transmembranic and cytoplasmic parts, acting thereby as endogenous regulatory mechanisms against systemic functions of cytokines. AIM: To measure serum concentrations of the soluble interleukin-2 receptor (sIL2R), soluble interleukin-4 receptor (sIL4R), soluble interleukin-6 receptor (sIL6R), and soluble tumor necrosis factor-alpha receptor I and soluble tumor necrosis factor-alpha receptor II, during the perinatal and early neonatal period, in order to evaluate their role in activation of immune response in labor and the first days postpartum. METHODS: Soluble receptor serum concentrations were determined by enzyme-linked immunosorbent assay, in 45 healthy, full-termed neonates during the first and fifth days after birth, in 25 of their mothers (MS), in 25 samples of umbilical cords (UC) and in 25 healthy adult donors age-matched with the mothers (controls). RESULTS: Soluble receptor serum concentrations showed considerable changes during labor and early neonatal life, being significantly higher both in MS (except sIL6R) and in neonatal sample UC, first and fifth days after birth, compared with controls (p<0.0001). Neonatal serum sIL2R and sIL6R increased significantly from birth to the fifth day, while the remaining receptors showed a rapid increase in the first day (p<0.0001), declining significantly thereafter (p<0.0001). CONCLUSION: Our findings suggest that the elevated concentrations of all studied soluble cytokine receptors reflect the activation of immune response, and represent also regulatory protective mechanisms for mother and fetus-neonate against the systemic function of cytokines during labor and early neonatal life. 相似文献
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Nikos Tritos Efthimia Kitraki Helen Phillipidis Fotini Stylianopoulou 《Cellular and molecular neurobiology》1998,18(5):525-534
1. Exposure to a combined forced swimming–confinement stress resulted in a decrease in insulin-like growth factor II (IGF-II) mRNA levels in the whole brain (without the cerebellum) and in the isolated brain areas of the cerebral cortex, the hippocampus, and the cerebellum.2. In an effort to elucidate the neurotransmitter systems involved in this stress-induced decrease, animals were injected prior to exposure to the stress, with either propranolol, diazepam, or MK-801.3. Administration of diazepam or MK-801 did not affect the stress-induced decrease in IGF-II mRNA in any of the three brain areas examined.4. Administration of propranolol prior to the exposure to the stress inhibited the stress-induced decrease in IGF-II mRNA in the cerebellum. Propranolol had no such effect in the cerebral cortex or the hippocampus.5. Our results suggest that in the cerebellum, the stress-induced decrease in IGF-II mRNA is mediated by 2-adrenergic receptors. 相似文献
8.
George Boukouvalas Kyriaki Gerozissis Efthimia Kitraki 《Cellular and molecular neurobiology》2010,30(4):521-530
The peripubertal period is critical for the final maturation of circuits controlling energy homeostasis and stress response.
However, the consequence of juvenile fat consumption on adult physiology is not clear. This study analyzed the adult consequences
of post-weaning fat feeding on limbic–hypothalamic–pituitary–adrenal (HPA) axis components and on metabolic regulators of
female rats. Wistar rats were fed either a high fat (HF) diet or the normal chow from weaning to puberty or to 3 months of
age. Additional groups crossed their diets at puberty onset. Plasma leptin, insulin, and corticosterone levels were determined
by radioimmunoassay and their brain receptors by western blot analysis. Adult HF-fed animals though not overweight, had higher
corticosterone and reduced glucocorticoid receptor levels in the hypothalamus and hippocampus, compared to the controls. The
alterations in HPA axis emerged already at puberty onset. Leptin receptor levels in the hypothalamus were reduced only by
continuous fat feeding from weaning to adulthood. The pre-pubertal period appeared more vulnerable to diet-induced alterations
in adulthood than the post-pubertal one. Switching from fat diet to normal chow at puberty onset restored most of the diet-induced
alterations in the HPA axis. The corticosteroid circuit rather than the leptin or insulin system appears as the principal
target for the peripubertal fat diet-induced effects in adult female rats. 相似文献
9.
I. E. Papadakis A. Giannakoula C. P. Antonopoulou M. Moustakas E. Avramaki I. N. Therios 《Photosynthetica》2007,45(2):208-213
Citrus volkameriana (L.) plants were grown for 43 d in nutrient solutions containing 0, 2, 14, 98, or 686 μM Mn (Mn0, Mn2, Mn14, Mn98, and Mn686, respectively). To adequately investigate the combined effects of Mn nutrition and irradiance on photosystem 2 (PS2) activity,
irradiance response curves for electron transport rate (ETR), nonphotochemical quenching (qN), photochemical quenching (qP), and real photochemical efficiency of PS2 (ΦPS2) were recorded under 10 different irradiances (66, 96, 136, 226, 336, 536, 811, 1 211, 1 911, and 3 111 μmol m−2 s−1, I66 to I3111, respectively) generated with the PAM-2000 fluorometer. Leaf chlorophyll content was significantly lower under Mn excess (Mn686) compared to Mn0; its highest values were recorded in the treatments Mn2-Mn98. However, ETR and ΦPS2 values were significantly lower under Mn0 compared to the other Mn treatments, when plants were exposed to irradiances ≥96 μmol m−2 s−1. Furthermore, Mn0 plants had significantly higher values of qN and lower values of qP at irradiances ≤226 and ≥336 μmol m−2 s−1, respectively, than those grown under Mn2-Mn686. Irrespective of Mn treatment, the values of ΦPS2 and qN decreased, while those of qP increased progressively by increasing irradiance from I136 to I3111. Finally, Mn2-Mn98 plants were less sensitive to photoinhibition of photosynthesis (≥811 μmol m−2 s−1) than the Mn686 (≥536 μmol m−2 s−1) and Mn0 (≥336 μmol m−2 s−1) ones. 相似文献
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