1.
A meta-analysis of transcriptomic profiles reveals molecular pathways response to cadmium stress of Gramineae.
Fan, W, Liu, C, Cao, B, Ma, S, Hu, J, Xiang, Z, Zhao, A
Ecotoxicology and environmental safety. 2021;:111816
Abstract
As a non-essential heavy metal, cadmium (Cd) is toxic to plants. In the last 15 years, over 70 transcriptome studies have been published to decipher the molecular response mechanism against Cd stress in different plants. To extract generalization results from transcriptomic data across different plants and obtain some hub genes that respond to Cd stress, we carried out a meta-analysis of 32 published datasets. Cluster analysis revealed that plant species played a more decisive role than the media used and exposure time in the transcriptome patterns of plant roots response to Cd. The datasets from a Gramineae-like (GL) group were closer in clustering. 838 DEGs were commonly Cd-regulated in at least nine of 18 GL datasets. Gene ontology and KEGG pathway analyses revealed that oxidative stress-related terms and lignin synthesis-related terms were significantly enriched. Mapman analysis revealed that these common DEGs were mainly involved in regulation, cellular response, secondary metabolism, transport, cell wall and lipid metabolism. In Oryza sativa, 15 DEGs were up-regulated in at least four of five HM (As, Cr, Cd, Hg and Pb) groups, such as Os10g0517500 (methionine gamma-lyase) and Os01g0159800 (bHLH107). Moreover, our datasets can be used to retrieve log2FC value of specific genes across 29 studies (48 datasets), which provides data reference for the subsequent selection of HM-related genes. Our results provide the basis for further understanding of Cd tolerance mechanisms in plants.
2.
Ghrelin as a Biomarker of Stress: A Systematic Review and Meta-Analysis.
Bouillon-Minois, JB, Trousselard, M, Thivel, D, Gordon, BA, Schmidt, J, Moustafa, F, Oris, C, Dutheil, F
Nutrients. 2021;(3)
Abstract
INTRODUCTION Ghrelin is an orexigenic hormone which favors food-seeking behavior and has been postulated to be a biomarker of stress. We conducted a systematic review and meta-analysis on the evolution of ghrelin levels following acute stress. METHODS The PubMed, Cochrane Library, Embase, and ScienceDirect databases were searched for studies reporting ghrelin levels before and after acute stress in humans. RESULTS We included ten studies for a total of 348 patients. Acute stress (intervention) was always in a laboratory. Acute stress was psychological (Trier Social Stress Test), physical, or mixed (cold pressure test). The overall meta-analysis demonstrated an increase in ghrelin after the stress intervention (ES = 0.21, 95CI 0.09 to 0.34) compared with baseline levels. Stratification by time demonstrated an acute increase in ghrelin levels in the five minutes immediately following the initiation of stress (0.29, 0.10 to 0.48) but without any difference after. Obese individuals had a more significant (ES = 0.51, 95CI 0.18 to 0.84) and prolonged increase in ghrelin levels for up to 45 min compared with non-obese individuals who had a significant increase only five minutes after stress. Moreover, the ghrelin levels increased in response to stress with BMI (coefficient 0.028, 0.01 to 0.49; p = 0.013) and decreased with the time after the stress intervention (coefficient -0.007, -0.014 to -0.001; p = 0.025). CONCLUSION Ghrelin is a biomarker of stress, with a short-term increase following acute stress. Obese individuals have both a higher and prolonged response, emphasizing the link between obesity and stress.
3.
Cold water immersion and recovery from strenuous exercise: a meta-analysis.
Leeder, J, Gissane, C, van Someren, K, Gregson, W, Howatson, G
British journal of sports medicine. 2012;(4):233-40
4.
The determinants of leaf turgor loss point and prediction of drought tolerance of species and biomes: a global meta-analysis.
Bartlett, MK, Scoffoni, C, Sack, L
Ecology letters. 2012;(5):393-405
Abstract
Increasing drought is one of the most critical challenges facing species and ecosystems worldwide, and improved theory and practices are needed for quantification of species tolerances. Leaf water potential at turgor loss, or wilting (π(tlp) ), is classically recognised as a major physiological determinant of plant water stress response. However, the cellular basis of π(tlp) and its importance for predicting ecological drought tolerance have been controversial. A meta-analysis of 317 species from 72 studies showed that π(tlp) was strongly correlated with water availability within and across biomes, indicating power for anticipating drought responses. We derived new equations giving both π(tlp) and relative water content at turgor loss point (RWC(tlp) ) as explicit functions of osmotic potential at full turgor (π(o) ) and bulk modulus of elasticity (ε). Sensitivity analyses and meta-analyses showed that π(o) is the major driver of π(tlp) . In contrast, ε plays no direct role in driving drought tolerance within or across species, but sclerophylly and elastic adjustments act to maintain RWC(tlp,) preventing cell dehydration, and additionally protect against nutrient, mechanical and herbivory stresses independent of drought tolerance. These findings clarify biogeographic trends and the underlying basis of drought tolerance parameters with applications in comparative assessments of species and ecosystems worldwide.