The symbiosis between rhizobia and legumes is characterized by a complex molecular dialogue in which the bacterial NodD protein plays a major role due to its capacity to activate the expression of ...the nodulation genes in the presence of appropiate flavonoids. These genes are involved in the synthesis of molecules, the nodulation factors (NF), responsible for launching the nodulation process. Rhizobium tropici CIAT 899, a rhizobial strain that nodulates Phaseolus vulgaris, is characterized by its tolerance to multiple environmental stresses such as high temperatures, acidity or elevated osmolarity. This strain produces nodulation factors under saline stress and the same set of CIAT 899 nodulation genes activated by inducing flavonoids are also up-regulated in a process controlled by the NodD2 protein. In this paper, we have studied the effect of osmotic stress (high mannitol concentrations) on the R. tropici CIAT 899 transcriptomic response. In the same manner as with saline stress, the osmotic stress mediated NF production and export was controlled directly by NodD2. In contrast to previous reports, the nodA2FE operon and the nodA3 and nodD1 genes were up-regulated with mannitol, which correlated with an increase in the production of biologically active NF. Interestingly, in these conditions, this regulatory protein controlled not only the expression of nodulation genes but also the expression of other genes involved in protein folding and synthesis, motility, synthesis of polysaccharides and, surprinsingly, nitrogen fixation. Moreover, the non-metabolizable sugar dulcitol was also able to induce the NF production and the activation of nod genes in CIAT 899.
ABSTRACT
The consumption of sugar-free foods is growing because of their low-calorie content and the health concerns about products with high sugar content. Sweeteners that are frequently several ...hundred thousand times sweeter than sucrose are being consumed as sugar substitutes. Although nonnutritive sweeteners (NNSs) are considered safe and well tolerated, their effects on glucose intolerance, the activation of sweet taste receptors, and alterations to the composition of the intestinal microbiota are controversial. This review critically discusses the evidence supporting the effects of NNSs, both synthetic sweeteners (acesulfame K, aspartame, cyclamate, saccharin, neotame, advantame, and sucralose) and natural sweeteners (NSs; thaumatin, steviol glucosides, monellin, neohesperidin dihydrochalcone, and glycyrrhizin) and nutritive sweeteners (polyols or sugar alcohols) on the composition of microbiota in the human gut. So far, only saccharin and sucralose (NNSs) and stevia (NS) change the composition of the gut microbiota. By definition, a prebiotic is a nondigestible food ingredient, but some polyols can be absorbed, at least partially, in the small intestine by passive diffusion: however, a number of them, such as isomaltose, maltitol, lactitol, and xylitol, can reach the large bowel and increase the numbers of bifidobacteria in humans. Further research on the effects of sweeteners on the composition of the human gut microbiome is necessary.
Ammonia (electro)oxidation with molecular catalysts is a rapidly developing topic with wide practical applications ahead. We report here the catalytic ammonia oxidation reaction (AOR) activity using ...Ru(tda-κ-N3O)(py)2, 2, (tda2– is 2,2′:6′,2′′-terpyridine-6,6′′-dicarboxylate; py is pyridine) as a catalyst precursor. Furthermore, we also describe the rich chemistry associated with the reaction of Ru-tda and Ru-tPa (tPa–4 is 2,2′:6′,2′′-terpyridine-6,6′′-diphosphonate) complexes with NH3 and N2H4 using RuII(tda-κ-N3O)(dmso)Cl (dmso is dimethyl sulfoxide) and RuII(tPa-κ-N3O)(py)2, 8, as synthetic intermediates, respectively. All the new complexes obtained here were characterized spectroscopically by means of UV–vis and NMR. In addition, a crystal X-ray diffraction analysis was performed for complexes trans-RuII(tda-κ-N3)(py)2(NH3), 4, trans-RuII(tda-κ-N3)(N-NH2)(py)2, 5, cis-RuII(tda-κ-N3)(py)(NH3)2, 6 (30%), and cis-RuII(tda-k-N3)(dmso)(NH3)2, 7 (70%). The AOR activity associated with 2 and 8 as catalyst precursors was studied in organic and aqueous media. For 2, turnover numbers of 7.5 were achieved under bulk electrolysis conditions at an E app = 1.4 V versus normal hydrogen electrode in acetonitrile. A catalytic cycle is proposed based on electrochemical and kinetic evidence.
Background and Aim
Endoscopic ultrasonography (EUS)‐guided drainage (EUS‐D) has become the standard treatment for peripancreatic fluid collections. Its use in other intra‐abdominal abscesses has been ...reported, although there is limited evidence.
Methods
We carried out a single‐center retrospective cohort study comparing percutaneous drainage (PCD) and EUS‐D of upper abdominal abscesses between January 2012 and June 2017. Pancreatic fluid collections and liver transplant recipients were excluded. Primary endpoints were technical and clinical success rates.
Results
We included 18 EUS‐D (nine hepatic and nine intraperitoneal abscesses) and 62 PCD. There were no differences regarding age, gender and etiology. Size was larger in the PCD group (80 vs 65.5 mm, P = 0.04) and perivesicular location was more frequent in the PCD group (24.2% vs 11.1%, P = 0.003). In the EUS‐D group, metal stents were deployed in 16 (88.9%) subjects (eight lumen‐apposing metal stents and eight self‐expandable metal stents), coaxial double‐pigtail plastic stents in six (33.3%) and lavage/debridement was carried out in five (27.8%). There were no significant differences in technical success (EUS‐D: 88.9%, PCD: 96.8%, P = 0.22) or clinical success (EUS‐D: 88.9%, PCD: 82.3%, P = 0.50), with no relapses in the EUS‐D group and 10 (16.1%) in the PCD group (P = 0.11). There were four (22.2%) adverse events in the EUS‐D group, none of them severe, and 13 (21%) in the PCD group (P = 0.91).
Conclusions
EUS‐D is an alternative to PCD in the treatment of upper abdominal abscesses, reaching similar success, relapse and adverse events rates.
► Flavonoids exuded by common bean under biotic and abiotic stresses were determined. ► Chryseobacterium balustinum affects the pattern of flavonoids exuded by common bean. ► Changes in the pattern ...of flavonoids observed are not related to salt stress. ► nod genes induction by root-exuded flavonoids and LCOs production were investigated.
Root exudates affect the concentration of nutrients in the plant rhizosphere and indirectly enhance microbial activity. Flavonoids are polyphenolic compounds that play an important role as signal molecules in the early stages of the symbiosis between legumes and rhizobia. Flavonoids from root exudates of Phaseolus vulgaris cv. Bush Blue Lake obtained under control conditions, salt stress (50mM), and/or the presence of the plant growth-promoting rhizobacterium (PGPR) Chryseobacterium balustinum Aur9 were analyzed by HPLC coupled to ESI-MS/MS. Six flavonoids were identified in the root exudates of P. vulgaris cv. BBL: naringenin, isoliquiritigenin, quercetin umbelliferone, 7′,4-dihydroxyflavone, and hesperetin. The latter three flavonoids have not previously been reported in bean root exudates. The presence of C. balustinum, but not salt stress, modified the pattern of flavonoids exuded by the bean roots. The capacity of flavonoids from root exudates to induce the expression of the nod genes and the production of lipochitooligosaccharides (LCOs) was investigated in two bean-nodulating rhizobia, Rhizobium tropici CIAT899 and Rhizobium etli ISP42. The R. etli ISP42 LCOs profile changed when it was induced by the exudates collected in the presence of the PGPR with and without salt. In the case of R. tropici CIAT899, changes in the LCOs profile were detected when the bacterium was induced with the different bean root exudates in comparison with the LCOs synthesized upon induction with apigenin.
The scientific scenario of amyotrophic lateral sclerosis (ALS) has dramatically changed since TDP-43 aggregates were discovered in 2006 as the main component of the neuronal inclusions seen in the ...disease, and more recently, when the implication of C9ORF72 expansion in familial and sporadic cases of ALS and frontotemporal dementia was confirmed. These discoveries have enlarged an extense list of genes implicated in different cellular processes such as RNA processing or autophagia among others and have broaden the putative molecular targets of the disease. Some of ALS-related genes such as TARDBP or SOD1 among others have important roles in the regulation of glucose and fatty acids metabolism, so that an impairment of fatty acids (FA) consumption and ketogenic deficits during exercise in ALS patients would connect the physiopathology with some of the more intriguing epidemiological traits of the disease. The current understanding of ALS as part of a continuum with other neurodegenerative diseases and a crossroads between genetic, neurometabolic and environmental factors represent a fascinating model of interaction that could be translated to other neurodegenerative diseases. In this review we summarize the most relevant data obtained in the ten last years and the key lines for future research in ALS.
Probiotics and synbiotics are used to treat chronic diseases, principally due to their role in immune system modulation and the anti-inflammatory response. The present study reviewed the effects of ...probiotics and synbiotics on intestinal chronic diseases in in vitro, animal, and human studies, particularly in randomized clinical trials. The selected probiotics exhibit in vitro anti-inflammatory properties. Probiotic strains and cell-free supernatants reduced the expression of pro-inflammatory cytokines via action that is principally mediated by toll-like receptors. Probiotic administration improved the clinical symptoms, histological alterations, and mucus production in most of the evaluated animal studies, but some results suggest that caution should be taken when administering these agents in the relapse stages of IBD. In addition, no effects on chronic enteropathies were reported. Probiotic supplementation appears to be potentially well tolerated, effective, and safe in patients with IBD, in both CD and UC. Indeed, probiotics such as
536 improved the clinical symptoms in patients with mild to moderate active UC. Although it has been proposed that probiotics can provide benefits in certain conditions, the risks and benefits should be carefully assessed before initiating any therapy in patients with IBD. For this reason, further studies are required to understand the precise mechanism by which probiotics and synbiotics affect these diseases.
Physicians in the emergency department (ED) need additional tools to stratify patients with acute heart failure (AHF) according to risk.
To predict mortality using data that are readily available at ...ED admission.
Prospective cohort study.
34 Spanish EDs.
The derivation cohort included 4867 consecutive ED patients admitted during 2009 to 2011. The validation cohort comprised 3229 patients admitted in 2014.
88 candidate risk factors and 30-day mortality.
Thirteen independent risk factors were identified in the derivation cohort and were combined into an overall score, the MEESSI-AHF (Multiple Estimation of risk based on the Emergency department Spanish Score In patients with AHF) score. This score predicted 30-day mortality with excellent discrimination (c-statistic, 0.836) and calibration (Hosmer-Lemeshow P = 0.99) and provided a steep gradient in 30-day mortality across risk groups (<2% for patients in the 2 lowest risk quintiles and 45% in the highest risk decile). These characteristics were confirmed in the validation cohort (c-statistic, 0.828). Multiple sensitivity analyses did not find important amounts of confounding or bias.
The study was confined to a single country. Participating EDs were not selected randomly. Many patients had missing data. Measurement of some risk factors was subjective.
This tool has excellent discrimination and calibration and was validated in a different cohort from the one that was used to develop it. Physicians can consider using this tool to inform clinical decisions as further studies are done to determine whether the tool enhances physician decision making and improves patient outcomes.
Instituto de Salud Carlos III, Spanish Ministry of Health; Fundació La Marató de TV3; and Catalonia Govern.
Over the last several years, the increasing prevalence of obesity has favored an intense study of adipose tissue biology and the precise mechanisms involved in adipocyte differentiation and ...adipogenesis. Adipocyte commitment and differentiation are complex processes, which can be investigated thanks to the development of diverse in vitro cell models and molecular biology techniques that allow for a better understanding of adipogenesis and adipocyte dysfunction associated with obesity. The aim of the present work was to update the different animal and human cell culture models available for studying the in vitro adipogenic differentiation process related to obesity and its co-morbidities. The main characteristics, new protocols, and applications of the cell models used to study the adipogenesis in the last five years have been extensively revised. Moreover, we depict co-cultures and three-dimensional cultures, given their utility to understand the connections between adipocytes and their surrounding cells in adipose tissue.
Mechanisms of Action of Probiotics Plaza-Diaz, Julio; Ruiz-Ojeda, Francisco Javier; Gil-Campos, Mercedes ...
Advances in nutrition (Bethesda, Md.),
01/2019, Letnik:
10, Številka:
suppl_1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
Probiotics are living microorganisms that confer health benefits to the host when administered in adequate amounts; however, dead bacteria and their components can also exhibit probiotic ...properties. Bifidobacterium and strains of lactic acid bacteria are the most widely used bacteria that exhibit probiotic properties and are included in many functional foods and dietary supplements. Probiotics have been shown to prevent and ameliorate the course of digestive disorders such as acute, nosocomial, and antibiotic-associated diarrhea; allergic disorders such as atopic dermatitis (eczema) and allergic rhinitis in infants; and Clostridium difficile–associated diarrhea and some inflammatory bowel disorders in adults. In addition, probiotics may be of interest as coadjuvants in the treatment of metabolic disorders, including obesity, metabolic syndrome, nonalcoholic fatty liver disease, and type 2 diabetes. However, the mechanisms of action of probiotics, which are diverse, heterogeneous, and strain specific, have received little attention. Thus, the aim of the present work was to review the main mechanisms of action of probiotics, including colonization and normalization of perturbed intestinal microbial communities in children and adults; competitive exclusion of pathogens and bacteriocin production; modulation of fecal enzymatic activities associated with the metabolization of biliary salts and inactivation of carcinogens and other xenobiotics; production of short-chain and branched-chain fatty acids, which, in turn, have wide effects not only in the intestine but also in peripheral tissues via interactions with short-chain fatty acid receptors, modulating mainly tissue insulin sensitivity; cell adhesion and mucin production; modulation of the immune system, which results mainly in the differentiation of T-regulatory cells and upregulation of anti-inflammatory cytokines and growth factors, i.e., interleukin-10 and transforming growth factor; and interaction with the brain-gut axis by regulation of endocrine and neurologic functions. Further research to elucidate the precise molecular mechanisms of action of probiotics is warranted.
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