Comparative Analysis of Autoxidation of Haemoglobin

2001 ◽  
Vol 204 (11) ◽  
pp. 2029-2033
Author(s):  
Frank B. Jensen
Keyword(s):  
Temperature Sensitivity ◽  
Oxidation Rate ◽  
Protective Role ◽  
Yellowfin Tuna ◽  
Histidine Residue ◽  
River Lamprey ◽  
Different Temperatures ◽  
Lower Temperature ◽  
The Impact

SUMMARY Autoxidation of oxyhaemoglobin (oxyHb) to methaemoglobin was measured at different temperatures in haemoglobin solutions from Atlantic hagfish, river lamprey, common carp, yellowfin tuna and pig. The aims were to evaluate the impact of the absent distal histidine in hagfish haemoglobin, the importance of oxyHb being either monomeric (hagfish and lamprey) or tetrameric (carp, tuna and pig) and to gain information on the temperature-sensitivity of autoxidation. The rate of autoxidation was lower in hagfish than in carp, yellowfin tuna and lamprey haemoglobins at any given temperature. Substitution of the distal histidine residue (His E7) with glutamine in hagfish haemoglobin was therefore not associated with an accelerated autoxidation, as might be expected on the basis of the normal protective role of His E7. Glutamine may have similar qualities to histidine and be involved in the low susceptibility to autoxidation. The low oxidation rate of hagfish haemoglobin, together with an oxidation rate of lamprey haemoglobin that did not differ from that of carp and yellowfin tuna haemoglobins, also revealed that autoxidation was not accelerated in the monomeric oxyhaemoglobins. Pig haemoglobin was oxidised more slowly than fish haemoglobins, demonstrating that fish haemoglobins are more sensitive to autoxidation than mammalian haemoglobins. The rate of autoxidation of hagfish haemoglobin was, however, only significantly greater than that of pig haemoglobin at high temperatures. Autoxidation was accelerated by rising temperature in all haemoglobins. Arrhenius plots of carp and yellowfin tuna haemoglobin revealed a break at 25°C, reflecting a lower temperature-sensitivity between 5 and 25°C than between 25 and 40°C.

scholarly journals Autophagy plays a protective role during Pseudomonas aeruginosa-induced apoptosis via ROS–MAPK pathway

2020 ◽  
Vol 26 (7) ◽  
pp. 580-591
Author(s):  
Lu Han ◽  
Qinmei Ma ◽  
Jialin Yu ◽  
Zhaoqian Gong ◽  
Chenjie Ma ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mapk Pathway ◽  
Protective Role ◽  
Vital Role ◽  
Raw264.7 Cells ◽  
Cellular Reactive Oxygen Species ◽  
Induced Apoptosis ◽  
Related Proteins ◽  
The Impact

Pseudomonas aeruginosa infection can induce alveolar macrophage apoptosis and autophagy, which play a vital role in eliminating pathogens. These two processes are usually not independent. Recently, autophagy has been found to interact with apoptosis during pathogen infections. Nevertheless, the role of autophagy in P. aeruginosa-infected cell apoptosis is unclear. In this study, we explored the impact of P. aeruginosa infection on autophagy and apoptosis in RAW264.7 cells. The autophagy activator rapamycin was used to stimulate autophagy and explore the role of autophagy on apoptosis in P. aeruginosa-infected RAW264.7 cells. The results indicated that P. aeruginosa infection induced autophagy and apoptosis in RAW264.7 cells, and that rapamycin could suppress P. aeruginosa-induced apoptosis by regulating the expression of apoptosis-related proteins. In addition, rapamycin scavenged the cellular reactive oxygen species (ROS) and diminished p-JNK, p-ERK1/2 and p-p38 expression of MAPK pathways in RAW264.7 cells infected with P. aeruginosa. In conclusion, the promotion of autophagy decreased P. aeruginosa-induced ROS accumulation and further attenuated the apoptosis of RAW264.7 cells through MAPK pathway. These results provide novel insights into host–pathogen interactions and highlight a potential role of autophagy in eliminating P. aeruginosa.

scholarly journals The Impact of Coronavirus Disease 2019 Lockdown on Athletes’ Subjective Vitality: The Protective Role of Resilience and Autonomous Goal Motives

2021 ◽  
Vol 11 ◽  
Author(s):  
Natalia Martínez-González ◽  
Francisco L. Atienza ◽  
Inés Tomás ◽  
Joan L. Duda ◽  
Isabel Balaguer
Keyword(s):  
Linear Models ◽  
Well Being ◽  
Protective Role ◽  
Subjective Vitality ◽  
Huge Impact ◽  
Mediational Role ◽  
The Impact ◽  
The Relationship ◽  
Over Time

The lockdown resulting from coronavirus disease 2019 (COVID-19) has had a huge impact on peoples’ health. In sport specifically, athletes have had to deal with frustration of their objectives and changes in their usual training routines. The challenging and disruptive situation could hold implications for their well-being. This study examined the effect of the COVID-19 lockdown on changes in athletes’ reported eudaimonic well-being (subjective vitality) and goal motives (autonomous and controlled) over time (i.e., pre-lockdown and during lockdown). The relationship of resilience to changes in subjective vitality was also determined, and changes in athletes’ goal motives were examined as potential mediators. Participants were 127 Spanish university athletes aged between 18 and 34 years (M = 21.14; SD = 2.77). Approximately 4 months before the start of the lockdown in Spain (T1), athletes responded to a questionnaire assessing their resilience, goal motives, and subjective vitality. Around 6 months later into the lockdown period (T2), athletes’ goal motives and subjective vitality were assessed again. Growth modeling using hierarchical linear models revealed a significant decrease of autonomous goal motives and subjective vitality during the lockdown, but athletes did not show change over time in controlled goal motives. Path analysis, adjusting T2 measures for their corresponding T1 measures, showed that resilience significantly predicted changes in athletes’ autonomous goal motives, which then accounted for changes in subjective vitality. The indirect effect was significant. Resilience did not predict changes in athletes’ controlled goal motives. However, changes in controlled goal motives negatively predicted changes in subjective vitality during lockdown. The findings suggest negative impacts of the COVID-19 lockdown on athletes’ goal motives and eudaimonic well-being. Results also support the hypothesized mediational role of autonomous goal motives in the relationship between resilience and subjective vitality during the lockdown. As such, findings confirm the relevance of resilience to a key feature of athletes’ eudaimonic well-being and the importance of enhancing their autonomous goal striving.

scholarly journals Infection-induced miR-126 suppresses tsc1- and cxcl12a-dependent permissive macrophages during mycobacterial infection

2021 ◽  
Author(s):  
Kathryn Wright ◽  
Kumudika de Silva ◽  
Karren M. Plain ◽  
Auriol C. Purdie ◽  
Warwick J. Britton ◽  
...  
Keyword(s):  
Immune Response ◽  
Detrimental Effect ◽  
Mycobacterial Infection ◽  
Protective Role ◽  
Zebrafish Embryos ◽  
Zebrafish Model ◽  
Effector Pathways ◽  
The Impact ◽  
Mtor Signalling

AbstractRegulation of host microRNA (miRNA) expression is a contested node that controls the host immune response to mycobacterial infection. The host must overcome concerted subversive efforts of pathogenic mycobacteria to launch and maintain a protective immune response. Here we examine the role of miR-126 in the zebrafish model of Mycobacterium marinum infection and identify a protective role for this infection-induced miRNA through multiple effector pathways. Specifically, we analyse the impact of the miR-126 knockdown-induced tsc1a and cxcl12a/ccl2/ccr2 signalling axes during early host-M. marinum interactions. We find a strong detrimental effect of tsc1a upregulation that renders zebrafish embryos susceptible to higher bacterial burden and increased cell death despite dramatically higher recruitment of macrophages to the site of infection. We demonstrate that infection-induced miR-126 suppresses tsc1 and cxcl12a expression thus improving macrophage function early in infection, partially through activation of mTOR signalling and strongly through preventing the recruitment of Ccr2+ permissive macrophages, resulting in the recruitment of protective tnfa-expressing macrophages. Together our results demonstrate an important role for infection-induced miR-126 in shaping an effective immune response to M. marinum infection in zebrafish embryos.

FGF21 prevents low protein diet-induced renal inflammation in aged mice

2021 ◽  
Author(s):  
Han Fang ◽  
Sujoy Ghosh ◽  
Landon Sims ◽  
Kirsten P. Stone ◽  
Cristal M Hill ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Renal Damage ◽  
Protective Role ◽  
Wild Type ◽  
Kidney Weight ◽  
Albumin Creatinine Ratio ◽  
Low Protein ◽  
The Impact ◽  
Protein Diets

Low protein diets extend lifespan through a comprehensive improvement in metabolic health across multiple tissues and organs. Many of these metabolic responses to protein restriction are secondary to transcriptional activation and release of FGF21 from the liver. However, the effects of a low protein (LP) diet on the kidney in the context of aging has not been examined. Therefore, the goal of the current study was to investigate the impact of chronic consumption of a LP diet on the kidney in aging mice lacking FGF21. Wild type (WT, C57BL/6J) and FGF21 KO mice were fed a normal protein (NP, 20% casein) or a LP (5% casein) diet ad libitum from 3 to19 months of age. The LP diet led to a decrease in kidney weight and urinary albumin/creatinine ratio in both WT and FGF21 KO mice. Although the LP diet produced only mild fibrosis and infiltration of leukocytes in WT kidneys, the effects were significantly exacerbated by the absence of FGF21. Accordingly, transcriptomic analysis showed that inflammation-related pathways were significantly enriched and upregulated in response to LP diet in FGF21 KO but not WT mice. Collectively, these data demonstrate that the LP diet negatively affected the kidney during aging, but in the absence of FGF21, the LP diet-induced renal damage and inflammation were significantly worse, indicating a protective role of FGF21 in the kidney.

Trauma symptoms contribute to daily experiential avoidance: Does partner support mitigate risk?

2020 ◽  
Vol 38 (1) ◽  
pp. 322-341
Author(s):  
Molly R. Franz ◽  
Rebecca L. Brock ◽  
David DiLillo
Keyword(s):  
Experiential Avoidance ◽  
Protective Role ◽  
Partner Support ◽  
Trauma Symptoms ◽  
High Quality ◽  
Trauma Symptom ◽  
Latent Trajectory ◽  
Latent Trajectory Modeling ◽  
The Impact

Objective: The present study examined the protective role of partner support in reducing daily experiential avoidance (EA) associated with trauma symptoms in a sample of 154 couples during pregnancy. Background: Although psychological distress during pregnancy may hinder the developing bond between parents and infants after birth, high quality intimate partner support has the potential to enhance psychological wellbeing during pregnancy, particularly in the context of trauma. Specifically, partner support might mitigate the impact of trauma symptoms on maladaptive coping strategies such as EA by enabling individuals to safely encounter their distress. Method: Participants completed a semi-structured clinical interview of support and a PTSD symptom inventory, followed by home surveys of EA over 14 days. We examined growth trajectories of EA over 14 days using latent trajectory modeling within a dyadic framework. Results: Trauma symptom severity was associated with higher levels of EA across the 2 weeks; however, among women, the impact of trauma symptoms on EA was no longer significant when support from a partner was above average quality or higher. Findings also revealed partner effects; to the extent that women reported higher levels of trauma symptoms, their partners had higher levels of EA. Conclusion: Findings highlight the protective role of high quality support from intimate partners and suggest that trauma-related interventions targeting partner support processes, especially those implemented during pregnancy, might enhance recovery and prevent further distress and dysfunction among pregnant women experiencing trauma symptoms.

scholarly journals Nuclear Control of the Inflammatory Response in Mammals by Peroxisome Proliferator-Activated Receptors

PPAR Research ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-23 ◽  
Author(s):  
Stéphane Mandard ◽  
David Patsouris
Keyword(s):  
Inflammatory Response ◽  
Protective Role ◽  
Peroxisome Proliferator ◽  
Nuclear Control ◽  
Inflammatory Bowel ◽  
Peroxisome Proliferator Activated Receptors ◽  
Ppar Ligands ◽  
The Impact

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that play pivotal roles in the regulation of a very large number of biological processes including inflammation. Using specific examples, this paper focuses on the interplay between PPARs and innate immunity/inflammation and, when possible, compares it among species. We focus on recent discoveries establishing how inflammation and PPARs interact in the context of obesity-induced inflammation and type 2 diabetes, mostly in mouse and humans. We illustrate that PPARγability to alleviate obesity-associated inflammation raises an interesting pharmacologic potential. In the light of recent findings, the protective role of PPARαand PPARβ/δagainst the hepatic inflammatory response is also addressed. While PPARs agonists are well-established agents that can treat numerous inflammatory issues in rodents and humans, surprisingly very little has been described in other species. We therefore also review the implication of PPARs in inflammatory bowel disease; acute-phase response; and central, cardiac, and endothelial inflammation and compare it along different species (mainly mouse, rat, human, and pig). In the light of the data available in the literature, there is no doubt that more studies concerning the impact of PPAR ligands in livestock should be undertaken because it may finally raise unconsidered health and sanitary benefits.

The impact of environmental infections (parasites) on MS activity

2011 ◽  
Vol 17 (10) ◽  
pp. 1162-1169 ◽  
Author(s):  
Jorge Correale ◽  
Mauricio F Farez
Keyword(s):  
Disease Onset ◽  
Epidemiological Data ◽  
Molecular Data ◽  
Protective Role ◽  
Host Parasite ◽  
Developed World ◽  
The Impact ◽  
Specific Parasite ◽  
Parasite Exposure

MS incidence has significantly increased during the second half of the 20th century, generating considerable interest in analyzing the basis for this rise in the developed world. Particular emphasis is being placed on the role infections might play in exacerbating or preventing disease onset. Epidemiological data suggest that improvement in sanitation conditions and reduced exposure to infection might explain, at least in part, these changes. The hygiene hypothesis is not new and is currently used to explain the increasing incidence of allergies and other autoimmune diseases. Because helminths are powerful modulators of host immunity, some authors hypothesize that reduced parasite exposure due to improved hygiene conditions may favor MS development. We discuss epidemiological, experimental, clinical and molecular data supporting the protective role of helminthes against MS. Better understanding of host–parasite interactions caused by specific parasite molecules with immunomodulatory effects will help combat allergies and autoimmune disease without the price of untoward infection as a side-effect.

Effect of intracellular pH on force development depends on temperature in intact skeletal muscle from mouse

1996 ◽  
Vol 271 (3) ◽  
pp. C878-C886 ◽  
Author(s):  
R. W. Wiseman ◽  
T. W. Beck ◽  
P. B. Chase
Keyword(s):  
Muscle Fatigue ◽  
Intracellular Ph ◽  
Force Production ◽  
Resonance Spectroscopy ◽  
Dependent Inhibition ◽  
Effects Of Ph ◽  
Different Temperatures ◽  
Lower Temperature ◽  
Glycerinated Fibers

The cellular mechanism of muscle fatigue is still in debate. Opposite conclusions regarding the role of intracellular pH (pHi) in fatigue have been drawn from skinned fiber vs. isolated perfused muscle studies. Because these experiments are typically performed at different temperatures, we tested the hypothesis that temperature alters the effects of pH on force. Tetanic force of isolated mouse extensor digitorum longus was measured at temperatures between 13 and 25 degrees C in either normocapnia (5% CO2) or hypercapnia (25% CO2). Hypercapnia decreased pHi (monitored by 31P nuclear magnetic resonance spectroscopy) by the same amount at both 15 and 25 degrees C. However, inhibition of force by hypercapnia was greater at the lower temperature. A similar pattern of temperature-dependent inhibition of force by pH was observed in glycerinated fibers from rabbit psoas at maximum Ca2+ activation. We conclude that temperature differences are responsible for disparate conclusions on the role of pHi in muscle fatigue. Based on our results, we suggest that changes in pHi may have little or no role in the loss in force production associated with muscular fatigue at physiological temperatures.

Phase Transformation from Mg to MgH2 Studied by SEM Metallography

2009 ◽  
Vol 1216 ◽  
Author(s):  
Amelia Montone ◽  
Annalisa Aurora ◽  
Daniele Mirabile Gattia ◽  
Marco Vittori Antisari
Keyword(s):  
Phase Transformation ◽  
Kinetic Analysis ◽  
Hydrogenation Reaction ◽  
Hydrogen Gas ◽  
Thermodynamic Force ◽  
Different Temperatures ◽  
Lower Temperature ◽  
Experimental Findings ◽  
Kinetics Of

AbstractMetallographic information has been used to support the kinetic analysis and the relative experimental findings in the phase transformation from Mg to MgH2, by absorption of hydrogen gas. In particular the method provides detailed information on the role of localized features like catalyst particles and defects present in the sample, which is obtained from ball milled MgH2 enriched with 5wt% Fe. In this work we have compared the kinetics of the hydrogenation reaction carried out at two different temperatures while keeping constant the thermodynamic force driving the reaction. This last was achieved by carefully controlling the hydrogen gas pressure. Despite this fact, the sample microstructure shows a marked effect of the temperature on the nucleation mechanism. In particular we have noticed that the density of sites active for nucleation is higher at lower temperature.Instant nucleation deduced by the kinetic analysis was confirmed by comparing the microstructure of samples at different reaction stages.

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