Bacterial phytopathogens living on the surface or within plant tissues may experience oxidative stress because of the triggered plant defense responses. Although it has been suggested that polyamines ...can defend bacteria from this stress, the mechanism behind this action is not entirely understood. In this study, we investigated the effects of oxidative stress on the polyamine homeostasis of the plant pathogen Pseudomonas syringae and the functions of these compounds in bacterial stress tolerance. We demonstrated that bacteria respond to H
O
by increasing the external levels of the polyamine putrescine while maintaining the inner concentrations of this compound as well as the analogue amine spermidine. In line with this, adding exogenous putrescine to media increased bacterial tolerance to H
O
. Deletion of arginine decarboxylase (speA) and ornithine decarboxylate (speC), prevented the synthesis of putrescine and augmented susceptibility to H
O
, whereas targeting spermidine synthesis alone through deletion of spermidine synthase (speE) increased the level of extracellular putrescine and enhanced H
O
tolerance. Further research demonstrated that the increased tolerance of the ΔspeE mutant correlated with higher expression of H
O
-degrading catalases and enhanced outer cell membrane stability. Thus, this work demonstrates previously unrecognized connections between bacterial defense mechanisms against oxidative stress and the polyamine metabolism.
To succeed in plant invasion, phytopathogenic bacteria rely on virulence mechanisms to subvert plant immunity and create favorable conditions for growth. This process requires a precise regulation in ...the production of important proteins and metabolites. Among them, the family of compounds known as polyamines have attracted considerable attention as they are involved in important cellular processes, but it is not known yet how phytopathogenic bacteria regulate polyamine homeostasis in the plant environment. In the present study, we performed a meta-analysis of publicly available transcriptomic data from experiments conducted on bacteria to begin delving into this topic and better understand the regulation of polyamine metabolism and its links to pathogenicity. We focused our research on
, an important phytopathogen that causes disease in many economically valuable plant species. Our analysis discovered that polyamine synthesis, as well as general gene expression activation and energy production are induced in the early stages of the disease. On the contrary, synthesis of these compounds is inhibited whereas its transport is upregulated later in the process, which correlates with the induction of virulence genes and the metabolism of nitrogen and carboxylic acids. We also found that activation of plant defense mechanisms affects bacterial polyamine synthesis to some extent, which could reduce bacterial cell fitness in the plant environment. Furthermore, data suggest that a proper bacterial response to oxidative conditions requires a decrease in polyamine production. The implications of these findings are discussed.
Polyamines (PAs) are natural aliphatic amines involved in many physiological processes in almost all living organisms, including responses to abiotic stresses and microbial interactions. On other ...hand, the family Leguminosae constitutes an economically and ecologically key botanical group for humans, being also regarded as the most important protein source for livestock. This review presents the profuse evidence that relates changes in PAs levels during responses to biotic and abiotic stresses in model and cultivable species within Leguminosae and examines the unreviewed information regarding their potential roles in the functioning of symbiotic interactions with nitrogen-fixing bacteria and arbuscular mycorrhizae in this family. As linking plant physiological behavior with "big data" available in "omics" is an essential step to improve our understanding of legumes responses to global change, we also examined integrative MultiOmics approaches available to decrypt the interface legumes-PAs-abiotic and biotic stress interactions. These approaches are expected to accelerate the identification of stress tolerant phenotypes and the design of new biotechnological strategies to increase their yield and adaptation to marginal environments, making better use of available plant genetic resources.Polyamines (PAs) are natural aliphatic amines involved in many physiological processes in almost all living organisms, including responses to abiotic stresses and microbial interactions. On other hand, the family Leguminosae constitutes an economically and ecologically key botanical group for humans, being also regarded as the most important protein source for livestock. This review presents the profuse evidence that relates changes in PAs levels during responses to biotic and abiotic stresses in model and cultivable species within Leguminosae and examines the unreviewed information regarding their potential roles in the functioning of symbiotic interactions with nitrogen-fixing bacteria and arbuscular mycorrhizae in this family. As linking plant physiological behavior with "big data" available in "omics" is an essential step to improve our understanding of legumes responses to global change, we also examined integrative MultiOmics approaches available to decrypt the interface legumes-PAs-abiotic and biotic stress interactions. These approaches are expected to accelerate the identification of stress tolerant phenotypes and the design of new biotechnological strategies to increase their yield and adaptation to marginal environments, making better use of available plant genetic resources.
Tea is one of the most widely consumed beverages, but its association with cancer risk remains controversial and unclear. We performed an umbrella review to clarify and determine the associations ...between tea consumption and various types of cancer by summarizing and recalculating the existing meta-analyses. Meta-analyses of observational studies reporting associations between tea consumption and cancer risk were searched on PubMed and Embase. Associations found to be statistically significant were further classified into levels of evidence (convincing, suggestive, or weak), based on P value, between-study heterogeneity, prediction intervals, and small study effects. Sixty-four observational studies (case-control or cohort) corresponding to 154 effect sizes on the incidence of 25 types of cancer were included. Forty-three (27.9%) results in 15 different types of cancer were statistically significant. When combining all studies on the same type of cancer, 19 results in 11 different types of cancer showed significant associations with lower risk of gastrointestinal tract organ cancer (oral, gastric, colorectal, biliary tract, and liver cancer), breast cancer, and gynecological cancer (endometrial and ovarian cancer) as well as leukemia, lung cancer, and thyroid cancer. Only the reduced risk of oral cancer in tea-consuming populations (OR = 0.62; 95% CI: 0.55, 0.72; P value < 10−6) was supported by convincing evidence. Suggestive evidence was found for 6 results on biliary tract, breast, endometrial, liver, and oral cancer. To summarize, tea consumption was shown to have protective effects on some types of cancer, particularly oral cancer. More well-designed prospective studies are needed with consideration of other factors that can cause biases.
People with mood disorders have increased risk of comorbid medical diseases versus the general population. It is paramount to identify interventions to improve physical health in this population.
...Umbrella review of meta-analyses of randomised controlled trials (RCTs) on pharmacological/non-pharmacological interventions for physical health outcomes/intolerability-related discontinuation in mood disorders (any age).
Ninety-seven meta-analyses were included. Among youths, against placebo, in depression, antidepressants/antipsychotics had higher discontinuation rates; in bipolar depression, olanzapine+fluoxetine worsened total cholesterol (TC)/triglycerides/weight gain (WG) (large ES). In adults with bipolar disorder, olanzapine worsened HbA1c/TC/WG (moderate/large ES); asenapine increased fasting glucose (small ES); quetiapine/cariprazine/risperidone induced WG (small/moderate ES). In bipolar depression, lurasidone was metabolically neutral. In depression, psychological interventions improved physical health-related quality of life (PHQoL) (small ES), fasting glucose/HbA1c (medium/large ES); SSRIs improved fasting glucose/HbA1c, readmission for coronary disease, pain (small ES); quetiapine/aripiprazole/olanzapine induced WG (small to large ES). Exercise improved cardiorespiratory fitness (moderate ES). In the elderly, fluoxetine yielded more detrimental cardiovascular effects than sertraline/escitalopram (large ES); antidepressants were neutral on exercise tolerance and PHQoL. In mixed age groups, in bipolar disorder aripiprazole was metabolically neutral; in depression, SSRIs lowered blood pressure versus placebo and serotonin-noradrenaline reuptake inhibitors (small ES); brexpiprazole augmentation caused WG and was less tolerated (small ES); exercise improved PHQoL (moderate ES).
Some interventions (psychological therapies, exercise and SSRIs) improve certain physical health outcomes in mood disorders, few are neutral, but various pharmacological interventions are associated with negative effects. Evidence from this umbrella review has limitations, should consider evidence from other disorders and should be integrated with recent evidence from individual RCTs, and observational evidence. Effective treatments with either beneficial or physically neutral profiles should be prioritized.
Multiple studies have suggested that ω-3 fatty acid intake may have a protective effect on cancer risk; however, its true association with cancer risk remains controversial. We performed an umbrella ...review of meta-analyses to summarize and evaluate the evidence for the association between ω-3 fatty acid intake and cancer outcomes. We searched PubMed, Embase, and the Cochrane Database of Systematic Reviews from inception to December 1, 2018. We included meta-analyses of observational studies that examined associations between intake of fish or ω-3 fatty acid and cancer risk (gastrointestinal, liver, breast, gynecologic, prostate, brain, lung, and skin) and determined the level of evidence of associations. In addition, we appraised the quality of the evidence of significant meta-analyses by using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We initially screened 598 articles, and 15 articles, including 57 meta-analyses, were eligible. Among 57 meta-analyses, 15 reported statistically significant results. We found that 12 meta-analyses showed weak evidence of an association between ω-3 fatty acid intake and risk of the following types of cancer: liver cancer (n = 4 of 6), breast cancer (n = 3 of 14), prostate cancer (n = 3 of 11), and brain tumor (n = 2 of 2). In the other 3 meta-analyses, studies of endometrial cancer and skin cancer, there were no assessable data for determining the evidence levels. No meta-analysis showed convincing, highly suggestive, or suggestive evidence of an association. In the sensitivity analysis of meta-analyses by study design, we found weak associations between ω-3 fatty acid intake and breast cancer risk in cohort studies, but no statistically significant association in case-control studies. However, the opposite results were found in case of brain tumor risk. Although ω-3 fatty acids have been studied in several meta-analyses with regard to a wide range of cancer outcomes, only weak associations were identified in some cancer types, with several limitations. Considering the nonsignificant or weak evidence level, clinicians and researchers should cautiously interpret reported associations between ω-3 fatty acid consumption and cancer risks.
Background: ERCP is frequently complicated by pancreatitis. The aims of this study were to assess the efficacy of somatostatin and gabexate for prevention of post-ERCP pancreatitis in high-risk ...patients and to determine predisposing factors for post-ERCP pancreatitis. A meta-analysis was conducted of all published studies on the use of somatostatin or gabexate for prevention of post-ERCP pancreatitis.
Methods: A double blind, multicenter, placebo-controlled trial was conducted in patients at high risk for post-ERCP pancreatitis. Patients were randomized to receive an intravenous infusion of somatostatin (750 mg), gabexate (500 mg), or placebo that was started 30 minutes before endoscopy and continued for 2 hours afterward. Patients were evaluated clinically and serum amylase levels determined at 4 and 24 hours after endoscopy.
Results: No significant difference in the occurrence of pancreatitis, hyperamylasemia, or abdominal pain was observed among placebo-, gabexate-, and somatostatin-treated patients. A sphincterotomy longer than 2 cm (
p = 0.0001), more than 3 pancreatic injections (
p = 0.0001), and unsuccessful cannulation (
p = 0.008) were predictive of post-ERCP pancreatitis. Hyperamylasemia was predicted by more than 3 pancreatic injections (
p = 0.0001) and sphincterotomy (
p = 0.02). The meta-analysis of trials of short-term infusion of gabexate or somatostatin did not show efficacy for either drug.
Conclusions: Short-term administration of gabexate or somatostatin in patients at high risk for pancreatitis is ineffective for prevention of ERCP-induced pancreatitis. Pancreatic injury is related to maneuvers used to obtain biliary access rather than to any patient characteristic or endoscopist experience. (Gastrointest Endosc 2002;56:488-95.)
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