scholarly journals New Evidence of Similarity between Human and Plant Steroid Metabolism: 5α-Reductase Activity in Solanum malacoxylon

Endocrinology ◽  
2003 ◽  
Vol 144 (1) ◽  
pp. 220-229 ◽  
Author(s):  
Fabiana Rosati ◽  
Giovanna Danza ◽  
Antonio Guarna ◽  
Nicoletta Cini ◽  
Milvia Luisa Racchi ◽  
...  
Keyword(s):  
Steroid Hormones ◽  
Metabolic Pathways ◽  
Reductase Activity ◽  
Physiological Role ◽  
Mechanisms Of Action ◽  
Plant Tissues ◽  
Solanum Malacoxylon ◽  
New Evidence ◽  
Mammalian System

Abstract The physiological role of steroid hormones in humans is well known, and the metabolic pathway and mechanisms of action are almost completely elucidated. The role of plant steroid hormones, brassinosteroids, is less known, but an increasing amount of data on brassinosteroid biosynthesis is showing unexpected similarities between human and plant steroid metabolic pathways. Here we focus our attention on the enzyme 5α-reductase (5αR) for which a plant ortholog of the mammalian system, DET2, was recently described in Arabidopsis thaliana. We demonstrate that campestenone, the natural substrate of DET2, is reduced to 5α-campestanone by both human 5αR isozymes but with different affinities. Solanum malacoxylon, which is a calcinogenic plant very active in the biosynthesis of vitamin D-like molecules and sterols, was used to study 5αR activity. Leaves and calli were chosen as examples of differentiated and undifferentiated tissues, respectively. Two separate 5αR activities were found in calli and leaves of Solanum using campestenone as substrate. The use of progesterone allowed the detection of both activities in calli. Support for the existence of two 5αR isozymes in S. malacoxylon was provided by the differential actions of inhibitors of the human 5αR in calli and leaves. The evidence for the presence of two isozymes in different plant tissues extends the analogies between plant and mammalian steroid metabolic pathways.

scholarly journals The physiological role of nucleobindin-2/nesfatin-1 and their potential clinical significance

2018 ◽  
Vol 72 ◽  
pp. 1084-1096
Author(s):  
Anna Skorupska ◽  
Andrzej Ożyhar ◽  
Dominika Bystranowska
Keyword(s):  
Cancer Cells ◽  
Metabolic Pathways ◽  
Physiological Role ◽  
Melanocortin System ◽  
Adrenocortical Cancer ◽  
Potential Biomarker ◽  
Treatment Of Obesity ◽  
High Level ◽  
Anorexigenic Effect

Nucleobindin-2 is a multidomain protein. Nucleobindin-2 can be cleaved into three peptide products: nesfatin-1, nesfatin-2 and nesfatin-3. It has been also shown that both Nucleobindin-2 and nesfatin-1 exhibit anorexigenic effect in rodents. In this review, we focused on a systematic characteristic of Nucleobindin-2, its anorexigenic effect and discussed possible mechanisms of its action. The first one is associated with melanocortin system and is leptin independent. The second – involves neurons that produce orexigenic neuropeptide Y. This has allowed integrating key findings which have important implications for treatment of obesity. We also presented Nucleobindin-2/nesfatin-1 as proteins which might become potentially important for understanding and treatment of such diseases as epilepsy, acute appendicitis or cancer. It has been shown that the Nucleobindin-2 function in cancerogenesis may be dual. The high level of Nucleobindin-2 and nesfatin-1 expression was found in colony, breast and endometrium cancer cells. Additionally, Nucleobindin-2/nesfatin-1 induced the proliferation process of these cells. In the future, Nucleobindin-2/nesfatin-1 may be used as a potential biomarker in diagnosis. However, Nucleobindin-2/nesfatin-1 inhibited ovarian and adrenocortical cancer cells proliferation and stimulated its apoptosis. The action of both proteins involved variety of metabolic pathways. The knowledge about activity control of Nucleobindin- 2/nesfatin-1 may contribute to new breakthrough in medicine.

scholarly journals Involvement of thiol transferase- and thioredoxin-dependent systems in the protection of ‘essential’ thiol groups of ornithine decarboxylase

1989 ◽  
Vol 259 (1) ◽  
pp. 111-115 ◽  
Author(s):  
F Flamigni ◽  
S Marmiroli ◽  
C M Caldarera ◽  
C Guarnieri
Keyword(s):  
Ornithine Decarboxylase ◽  
Reductase Activity ◽  
Physiological Role ◽  
Thioredoxin Reductase ◽  
Thiol Group ◽  
Transferase Activity ◽  
Strong Inhibitor ◽  
Activity Factor

Ornithine decarboxylase (ODC), an enzyme with ‘essential’ thiol group(s), may be inactivated in vitro by removal of thiol reducing agents and re-activated by soluble factors from rat liver in the presence of NADPH or GSH. The NADPH- and GSH-dependent reducing systems were separated and resolved into three components, called factors A, B1 and B2, by chromatographic techniques. Factor B1 (Mr 12,000) could reactivate ODC in the presence of GSH and co-purified with thiol transferase activity. Factor B2 (Mr 12,000) and factor A (Mr approx. 110,000) were both needed to re-activate ODC in the presence of NADPH, and co-purified with thioredoxin and thioredoxin reductase activity respectively. In an attempt to investigate the physiological role of the ‘essential’ thiol group(s) of ODC, erythroleukaemia cells were incubated with NN-bis-(2-chloroethyl)-N'-nitrosourea, t-butyl hydroperoxide and vinblastine, which are known to increase the cellular GSSG/GSH ratio, azelaic acid, an inhibitor of thioredoxin reductase, and sodium arsenite, a strong inhibitor of the ODC-re-activating factors. All these compounds were able to decrease significantly the ODC activity induced in these cells. These results suggest that the thiol transferase- and thioredoxin-dependent systems may be physiologically relevant in maintaining ODC in the active, reduced, state.

scholarly journals Adiponectin, the controversial hormone

2007 ◽  
Vol 10 (10A) ◽  
pp. 1145-1150 ◽  
Author(s):  
Marta Garaulet ◽  
Juan J Hernández-Morante ◽  
Fátima Pérez de Heredia ◽  
Francisco J Tébar
Keyword(s):  
Insulin Resistance ◽  
Plasma Concentrations ◽  
Physiological Role ◽  
Protective Role ◽  
Mechanisms Of Action ◽  
Acid Protein ◽  
Related Proteins ◽  
Contradictory Data ◽  
Amino Acid Protein

AbstractObjectiveTo discuss present knowledge about adiponectin hormone.DesignReview of existing literature.Setting and resultsAdiponectin is one of the most interesting cytokines associated with obesity, although its physiological role remains to be fully clarified. Adiponectin is a 247-amino acid protein that contains four differentiable domains. Contrary to most adipose-related cytokines, adiponectin levels are surprisingly lower in obese than in lean humans. Women have been found to have significantly higher adiponectin plasma concentrations than men. Further research is needed in order to identify new polymorphisms which contribute to explain the potential role of adiponectin in obesity and related pathologies.Considering the anti-inflammatory properties of adiponectin and the fact that it is negatively associated with adiposity, this cytokine could be one of the links between obesity and inflammation. The main mechanisms of action of adiponectin are directed to a protective role against atherogenic and insulin resistance processes. Research has revealed interesting new functions far beyond metabolism, such as immunity, cancer and bone formation.Contrary to all adipose-related proteins, adiponectin decreases with obesity. Most of the contradictory data surrounding adiponectin are related to plasma values and their relationship with body fat, gender differences and insulin resistance. There are important confounding results regarding the mechanisms of action and functions of adiponectin, especially in relation to insulin resistance and inflammation.

The role of vitamin A and its pro-vitamin carotenoids in fetal and neonatal programming: gaps in knowledge and metabolic pathways

2020 ◽  
Vol 79 (1) ◽  
pp. 76-87
Author(s):  
Leonardo M de Souza Mesquita ◽  
Laís V Mennitti ◽  
Veridiana V de Rosso ◽  
Luciana P Pisani
Keyword(s):  
Vitamin A ◽  
Nutritional Status ◽  
Metabolic Pathways ◽  
Metabolic Diseases ◽  
Biological Effects ◽  
Physiological Role ◽  
Current Data ◽  
Cellular Processes ◽  
Pregnancy And Lactation

Abstract Vitamin A (VA) and its pro-vitamin carotenoids are naturally occurring lipophilic compounds involved in several cellular processes and metabolic pathways. Despite their broad spectrum of activities in the general population, dietary deficiencies of these compounds can potentially affect pregnancy outcomes. Since maternal nutritional status and diet composition during pregnancy and lactation can have long-lasting effects in offspring until adulthood, this study presents an overview of VA and the role of pro-VA carotenoids during pregnancy and lactation – the nutrition, metabolism, and biological effects in the offspring. The review aimed to discuss the pro-VA carotenoids and VA-associated pathways and summarize the results with reference to gestational disorders, and VA and pro-VA carotenoids as preventive agents. Also, considering that obesity, overweight, and metabolic diseases are major public health concerns worldwide, fetal and neonatal development is discussed, highlighting the physiological role of these molecules in obesity prevention. This review comprehensively summarizes the current data and shows the potential impact of these compounds on nutritional status in pregnancy and lactation.

scholarly journals Physiological Role of Acyl Coenzyme A Synthetase Homologs in Lipid Metabolism in Neurospora crassa

2013 ◽  
Vol 12 (9) ◽  
pp. 1244-1257 ◽  
Author(s):  
Christine M. Roche ◽  
Harvey W. Blanch ◽  
Douglas S. Clark ◽  
N. Louise Glass
Keyword(s):  
Neurospora Crassa ◽  
Metabolic Pathways ◽  
Lipid Membrane ◽  
Coenzyme A ◽  
De Novo ◽  
Physiological Role ◽  
Functional Redundancy ◽  
Content Type ◽  
Acyl Coenzyme A

ABSTRACTAcyl coenzyme A (CoA) synthetase (ACS) enzymes catalyze the activation of free fatty acids (FAs) to CoA esters by a two-step thioesterification reaction. Activated FAs participate in a variety of anabolic and catabolic lipid metabolic pathways, includingde novocomplex lipid biosynthesis, FA β-oxidation, and lipid membrane remodeling. Analysis of the genome sequence of the filamentous fungusNeurospora crassaidentified seven putative fatty ACSs (ACS-1 through ACS-7). ACS-3 was found to be the major activator for exogenous FAs for anabolic lipid metabolic pathways, and consistent with this finding, ACS-3 localized to the endoplasmic reticulum, plasma membrane, and septa. Double-mutant analyses confirmed partial functional redundancy of ACS-2 and ACS-3. ACS-5 was determined to function in siderophore biosynthesis, indicating alternative functions for ACS enzymes in addition to fatty acid metabolism. TheN. crassaACSs involved in activation of FAs for catabolism were not specifically defined, presumably due to functional redundancy of several of ACSs for catabolism of exogenous FAs.

Serendipity reveals the function and physiological role of a large family of proteins.

2021 ◽  
Author(s):  
Diana Downs
Keyword(s):  
Metabolic Pathways ◽  
Physiological Role ◽  
Large Family ◽  
Microbial Metabolism ◽  
Endonuclease Activity ◽  
Fundamental Information ◽  
Original Question

Microbial metabolism involves a complex set of interactions between metabolic pathways that include proteins of both known and uncharacterized function. While investigating the physiological strategy used by actinomycetes with two RpoB paralogs, Damiano et al uncovered the endonuclease activity of a member of the Rid family. While this finding was peripheral to the original question posed by the authors, it has considerable significance. The study by Damiano et al highlights how unexpected, but fundamental, information can be gained by following phenotypic leads.

scholarly journals Molecular Characterization of an NADPH-Dependent Acetoin Reductase/2,3-Butanediol Dehydrogenase fromClostridium beijerinckiiNCIMB 8052

2014 ◽  
Vol 80 (6) ◽  
pp. 2011-2020 ◽  
Author(s):  
John Raedts ◽  
Marco A. J. Siemerink ◽  
Mark Levisson ◽  
John van der Oost ◽  
Servé W. M. Kengen
Keyword(s):  
Structural Model ◽  
Reductase Activity ◽  
Physiological Role ◽  
Clostridium Beijerinckii ◽  
Cofactor Specificity ◽  
Threonine Dehydrogenase ◽  
Important Enzyme ◽  
Electronegative Group

ABSTRACTAcetoin reductase is an important enzyme for the fermentative production of 2,3-butanediol, a chemical compound with a very broad industrial use. Here, we report on the discovery and characterization of an acetoin reductase fromClostridium beijerinckiiNCIMB 8052. Anin silicoscreen of theC. beijerinckiigenome revealed eight potential acetoin reductases. One of them (CBEI_1464) showed substantial acetoin reductase activity after expression inEscherichia coli. The purified enzyme (C. beijerinckiiacetoin reductase [Cb-ACR]) was found to exist predominantly as a homodimer. In addition to acetoin (or 2,3-butanediol), other secondary alcohols and corresponding ketones were converted as well, provided that another electronegative group was attached to the adjacent C-3 carbon. Optimal activity was at pH 6.5 (reduction) and 9.5 (oxidation) and around 68°C. Cb-ACR accepts both NADH and NADPH as electron donors; however, unlike closely related enzymes, NADPH is preferred (Km, 32 μM). Cb-ACR was compared to characterized close homologs, all belonging to the “threonine dehydrogenase and related Zn-dependent dehydrogenases” (COG1063). Metal analysis confirmed the presence of 2 Zn2+atoms. To gain insight into the substrate and cofactor specificity, a structural model was constructed. The catalytic zinc atom is likely coordinated by Cys37, His70, and Glu71, while the structural zinc site is probably composed of Cys100, Cys103, Cys106, and Cys114. Residues determining NADP specificity were predicted as well. The physiological role of Cb-ACR inC. beijerinckiiis discussed.

scholarly journals Resveratrol Improves the Iron Deficiency Adaptation of Malus Baccata Seedlings by Regulating Iron Absorption, Phytohormone Content, and ROS Migration

2021 ◽  
Author(s):  
Xiaodong Zheng ◽  
Huifang Chen ◽  
Qiufang Su ◽  
Caihong Wang ◽  
Guangli Sha ◽  
...  
Keyword(s):  
Iron Deficiency ◽  
Fungal Infections ◽  
Reductase Activity ◽  
Physiological Role ◽  
Rhizosphere Ph ◽  
Root Cells ◽  
Iron Solubility ◽  
Malus Baccata ◽  
Species Production

Abstract Resveratrol (Res), a phytoalexin, has been widely reported to participate in plant resistance to fungal infections. However, little information is available on its role in abiotic stress, especially in iron deficiency stress. Malus baccata is widely used as apple rootstock in China, but it is sensitive to iron deficiency. In this study, we investigated the role of exogenous Res in M. baccata seedings under iron deficiency stress. Results showed that applying 100 µmol exogenous Res could alleviate iron deficiency stress. The seedlings treated with Res had a lower etiolation rate and higher chlorophyll content and photosynthetic rate compared with the apple seedlings without Res treatment. Exogenous Res increased the iron content in the roots and leaves by inducing the expression of MbAHA genes and improving the H+-ATPase activity. As a result, the rhizosphere pH decreased, iron solubility increased, the expression of MbFRO2 and MbIRT1 was induced, and the ferric-chelated reductase activity was enhanced to absorb large amounts of Fe2+ into the root cells under iron deficiency conditions. Moreover, exogenous Res application increased the contents of IAA, ABA, and GA3 and decreased the contents of DHZR and BL for responding to iron deficiency stress indirectly. In addition, Res functioned as an antioxidant that strengthened the activities of antioxidant enzymes and thus eliminated reactive oxygen species production induced by iron deficiency stress. These findings are expected to enhance the application and examination of the physiological role of Res under iron deficiency stress in apples.

scholarly journals Gh is produced by the testis of Japanese eel and stimulates proliferation of spermatogonia

Reproduction ◽  
2011 ◽  
Vol 142 (6) ◽  
pp. 869-877 ◽  
Author(s):  
Chiemi Miura ◽  
Yosuke Shimizu ◽  
Maho Uehara ◽  
Yuichi Ozaki ◽  
Graham Young ◽  
...  
Keyword(s):  
Steroid Hormones ◽  
Germ Cells ◽  
Physiological Role ◽  
Somatic Growth ◽  
Japanese Eel ◽  
Expression Of Genes ◽  
Genes Encoding

Gh plays important roles in development, somatic growth and gametogenesis in vertebrates. To determine the physiological role of Gh in reproduction in male teleosts, the expression of genes encoding Gh and the two Gh receptors (Ghrs) during spermatogenesis, and the action of Ghin vitrowas examined using the Japanese eel (Anguilla japonica).gh,ghr1andghr2mRNA transcripts were detected in all spermatogenic stages.In situhybridization showed the presence ofghr1andghr2mRNA in the germ cells. Immunohistochemistry using an antiserum against eel Gh indicated that Gh protein was localized to Sertoli cells surrounding the germ cells in early spermatogenesis. Recombinant eel Gh induced spermatogonial proliferation in a testis organ culture system, an effect that was independent from the production of steroid hormones or Igf1. This study identifies a role for eel Gh in the regulation of early spermatogenesis, particularly in the mitotic phase of spermatogenesis, that is not mediated by either steroid hormones or Igf1 production.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

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