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Lipases are useful enzymes that are responsible for the hydrolysis of triacylglycerides and play an important role in plant growth. In this study, we report a rapid molecular method to amplify a partial sequence of the lipase class 3 family designated BnLIP3 gene of Brassica napus L. in order to follow its expression and analyze its role during seed germination. Therefore, we conceived PCR homologous primers to amplify the active site encoding region of the BnLIP3 family genes. Subsequently, to sequence determination of the 582 bp fragment, we deduced BnLIP3 specific primers for a nested RTPCR application. The deduced 194 amino acid sequence (Genbank 1160264) was found to share 85% of identity with lipase from Arabidopsis thaliana class 3 family. The GxSxG consensus motif near the catalytic triad at the active serine site was also identified. The peptidic sequence showed little homology with mammalian and microbial lipases. RT-PCR analysis indicated that BnLIP3 gene was expressed during B. napus seed germination.Keywords: Brassica napus L., GxSxG lipase, germination, BnLIP3, RT-PCR.African Journal of Biotechnology Vol. 12(25), pp. 3905-3913

[EN] Lipases catalyze the hydrolysis of ester bonds in triacylglycerides, generating glycerol and free fatty acids. These enzymes are encoded by extremely complex gene families, and appear to fulfil many different biological functions. Although they are present in all types of organisms, available information on plant lipases is still very limited, as compared to their bacterial and animal counterparts. A full-length clone, BnLIP, encoding a putative lipase, has been isolated by PCR amplification of Brassica napus genomic DNA, with oligonucleotide primers derived from the sequence of an Arabidopsis thaliana homologue. The clone included an open reading frame of 1581 bp encoding a polypeptide of 526 amino acids, with a calculated molecular mass of 59.5 kDa. Analysis of the deduced protein sequence, sequence alignment with homologous proteins from related plant species, and a phylogenetic analysis revealed that the BnLIP protein belongs to the classical GxSxG-motif lipase family. RTPCR assays indicated that the BnLIP gene is expressed specifically, but only transiently, during seed germination: the lipase mRNA was not present at detectable levels in ungerminated seeds, was detected only three days after seed imbibition, but its levels decreased rapidly afterwards. No expression was observed in roots, stems or leaves of adult plants. This expression pattern suggests that BnLIP is one of the lipases involved in the hydrolysis of triacylglycerides stored in rapeseed seeds, ultimately providing nutrients and energy to sustain seedling growth until photosynthesis is activated

International audience; The purpose of this study was to investigate the effect of subacute exposure to static magnetic fields (SMF) on hematological and muscle biochemical parameters in rats. Male Wistar rats, daily exposed to SMF, were exposed to SMF (128 mT, 1 h/day) during 15 consecutive days. SMF-exposed rats showed a significant decrease in red blood cell (RBC) count, hemoglobin (Hb), and hematocrit (Ht) values compared to sham-exposed rats (p

In the following study, we investigate the effects of static magnetic field (SMF) (128 mT, 1 h/day during 5 or 15 consecutive days) on anthropometric parameters, glucose and lipid metabolism in rats. Exposure to SMF during 5 days induced a decrease (-8%, p < 0.05) in relative liver weight and serum insulin concentration (-56%, p < 0.001), while blood glucose level was increased (+10%, p < 0.001). By contrast, the same treatment failed to alter body weight, relative kidney weight and levels of lactate, cholesterol, triglycerides and phospholipids. Exposure to SMF during 15 days induced a decrease (-15 %, p < 0.001) in body weight, liver weight (-15 %, p < 0.05), insulin concentration (-63%, p < 0.001), plasmatic lactate level (-55%, p < 0.05) and increased glucose (+24%, p < 0.001), cholesterol (+30%, p < 0.01,) and phospholipids levels (+58%, p < 0.001), whereas, triglycerides decreased (-28%, p < 0.001). These results showed that SMF effects on glucose and lipid metabolism are time-dependent.

Lipases play an important role in lipid metabolism and are produced by a variety of species. All lipases are members of the a/â hydrolase fold super-family. Also, lipases share a conserved active site signature, the Gly-Xaa-Ser-Xaa-Gly motif. To obtain an overview of this industrially and very important class of enzymes and their characteristics, we collected and classified bacterial lipases sequences available from protein databases. Here we proposed an updated and revised classification of family I bacterial "true" lipases based mainly on a comparison of their amino acid sequences and some fundamental physicochemical and biological properties. The result of this work has identified 11 subfamilies of “true” lipases. This work will therefore contribute to a faster identification and to an easier characterization and classification of novel bacterial lipolytic enzymes. Key words : Lipases, phylogenetic analysis, lipolytic enzymes.

A recent advance in the study of plant lipases involving immunological techniques is presented. In an attempt to characterize lipases of cotyledons from germinating rapeseed seedlings and to investigate an eventual cross-reactivity with animal lipases, we have prepared anti-porcine pancreatic lipase antibodies raised in rabbit. It is shown by enzyme-linked immunosorbent assay and dot-blotting that these antibodies react with lipases in the rapeseed crude extract and in the different cellular fractions obtained by differential centrifugation. Preincubation of the antiserum with the rapeseed crude extract affects the amount of antibodies binding to the porcine pancreatic lipase. We demonstrate immunochemical cross-reactivity between rapeseed and porcine pancreatic lipase. Using the immunoblotting procedure, it is found that antibodies bind specifically to a single polypeptide with a molecular mass of about 55 kDa. Rapeseed lipase activity decreased after immunoprecipitation suggesting that antibodies were bound to some catalytic site residues. We conclude from the data obtained in this study that the two different lipase species present close similarities in amino acid sequence and antigen characteristics.*

Lipase enzymes play an important role in lipid metabolism and are produced by a variety of species. Compared with animal, bacterial and fungal, little is known about plant lipases. Although lipases belong to many different protein families, they have the same architecture, the ?/?-hydrolase fold and a conserved active site signature, the Gly-Xaa-Ser-Xaa-Gly motif. Several studies on enzymatic activity and interfacial activation phenomenon of lipases confirm the presence of consensus sequence and a conserved domain. Lipases can be divided into two main groups: carboxylesterases (EC 3.1.1.1); |true| lipases (EC 3.1.1.3), which differ in several biochemical features, which allow us to develop a database that regroups all |true| lipase proprieties to establish relationship between structure and function. LIPABASE is a centralised resource database, which provides information about |true| lipase from different species. It includes general, taxonomic, physicochemical and molecular data. Access to LIPABASE is free and available at http://www.lipabase-pfba-tun.org.

Purpose: The aim of this study was to investigate if the metabolic alterations observed after static magnetic field (SMF) exposure participates in the development of a pre-diabetic state. A comparison study using the insulin resistant animal model, the Zucker rat and the SMF-exposed Wistar rat was carried out. Materials and methods: Zucker rats were compared to Wistar rats either exposed to a 128 mT or 0 mT SMF (sham exposed) and analysed. This moderate-intensity SMF exposure of Wistar rats was performed for 1 h/day during 15 consecutive days. Results: Wistar rats exposed to the SMF showed increased levels of carbohydrate and lipid metabolites (i.e., lactate, glycerol, cholesterol and phospholipids) compared to sham-exposed rats. Zucker rats displayed a normoglycemia associated with a high insulin level as opposed to Wistar rats which presented hyperglycemia and hypoinsulinemia after exposure to the SMF. During the glucose tolerance test, unexposed Zucker rats and Wistar rats exposed to the SMF exhibited a significantly higher hyperglycemia compared to sham-exposed Wistar rats suggesting an impairment of glucose clearance. In muscle, glycogen content was lower and phospholipids content was elevated for both unexposed Zucker rats and Wistar rats exposed to the SMF compared to Wistar rats sham control. Conclusions: This study provides evidence that the metabolic alterations following exposure to a static magnetic field of moderate intensity could trigger the development of a pre-diabetic state.

Triacylglycerol lipases have been thoroughly characterized in mammals and microorganisms. By contrast, very little is known about plant lipases. In this investigation, a homology model of Arabidopsis thaliana lipase (NP_179126) was constructed using a human gastric lipase (PDB ID: 1HLG), as a template for model building. This model was then assessed for stereochemical quality and side chain environment. Natural substrates: tributyrin, trioctanoin and triolen were docked into the model to investigate ligand-substrate interaction.

International audience; Background and Aims. Increasing environmental pollution may participate in the growing incidence of metabolic disorders. Static magnetic fields (SMFs) are an emerging environmental health issue due to increased exposure in residential and commercial areas; however, their metabolic effects in serum and skeletal muscle are largely unknown. The aim of this study was to investigate the effect of SMF exposure on glucose and lipid metabolism in serum and skeletal muscles of rats.Methods. Twelve 6-to 7-week-old male Wistar rats were randomly divided into two groups: rats exposed to 128 mT SMF and sham-exposed rats. This moderate-intensity exposure was performed for 1 h/day for 15 consecutive days.Results. Animals exposed to 128 mT SMF displayed significant changes in both glucose (i.e., increases in plasma glucose and lactate and decrease in plasma insulin levels) and lipid (i.e., increases in plasma glycerol, cholesterol and phospholipids but not triglyceride levels) metabolism. During intraperitoneal glucose tolerance tests, SMF-exposed rats displayed significantly higher hyperglycemia compared to sham-exposed rats despite similar insulin levels in both groups. In tissues, SMF exposure induced significant alterations in enzyme activities only in glycolytic muscles and caused a significant decrease in quadriceps and liver glycogen content together with increased phospholipid levels. Conclusions. This study provides evidence that subacute SMF exposure of moderate intensity induces important alterations of glucose and lipid metabolisms, which deserve further investigations to evaluate long-term consequences. Ó

El efecto sobre el crecimiento de Salmonella hadar fue investigado utilizando un medio liquido esteril fresco (Pronadisa, Hispanlab) conteniendo el extracto acuoso de ajo (EAA) en diferentes concentraciones (0, 11, 12 y 13 mg/ml). El extracto de ajo anadido con estas concentraciones tuvo un efecto bacteriostatico sobre Salmonella hadar. La prueba serovar revelo un patron de inhibicion caracterizado por: (i) una fase de inhibicion transitoria cuya duracion fue proporcional a la concentracion de EAA, (ii) una reanudacion de la fase de crecimiento, la cual mostro una tasa mas baja de crecimiento que controles sin inhibicion, y (iii) una ingreso en fase estacionaria con una menor densidad de cultivo. La concentracion minima inhibitoria (CMI) y la concentracion minima bactericida (CMB) fueron muy cercanas, la CMI de ajo fue de 12 mg/ml y la CMB fue de 14 mg/ml. Las actividades enzimaticas seguidas con el sistema API-ZYM, mostraron cambios significativos durante la fase de inhibicion. Estos cambios bioquimicos representan una respuesta adaptativa al estres del ajo. Algunas actividades enzimaticas celulares desaparecieron, mientras que otras fueron inducidas o mantenidas despues de la adicion de EAA. Las imagenes de MET de las muestras tratadas con la concentracion del bacteriostatico EAA (12 mg/ml) revelaron la ruptura de las paredes celulares y la disposicion no homogenea de materiales citoplasmaticos dentro de las bacterias tratadas.

A cross-reactivity between animal and plant lipases was determined, using immunological techniques. It was shown by ELISA and dot-blotting that these antibodies react with lipases in the rapeseed crude extract and in the different cellular fractions obtained by differential centrifugation. Pre-incubation of the antiserum with the rapeseed crude extract affects the amount of antibodies binding to the porcine pancreatic lipase. Antibodies were able to precipitate lipase activity from 3-day-old rapeseed crude extract. These epitopes seem to be located in the catalytic site, suggesting that a consensus sequence exists in oleaginous lipases and that it will be universal.

Background blaVEB-1 is an integron-located extended-spectrum β-lactamase gene initially detected in Escherichia coli and Pseudomonas aeruginosa strains from south-east Asia. Several recent studies have reported that VEB-1-positive strains are highly resistant to ceftazidime, cefotaxime and aztreonam antibiotics. One strategy to overcome resistance involves administering antibiotics together with β-lactamase inhibitors during the treatment of infectious diseases. During this study, four VEB-1 β-lactamase inhibitors were identified using computer-aided drug design. Methods The SWISS-MODEL tool was utilized to generate three dimensional structures of VEB-1 β-lactamase, and the 3D model VEB-1 was verified using PROCHECK, ERRAT and VERIFY 3D programs. Virtual screening was performed by docking inhibitors obtained from the ZINC Database to the active site of the VEB-1 protein using AutoDock Vina software. Results and conclusion Homology modeling studies were performed to obtain a three-dimensional structure of VEB-1 β-lactamase. The generated model was validated, and virtual screening of a large chemical ligand library with docking simulations was performed using AutoDock software with the ZINC database. On the basis of the dock-score, four molecules were subjected to ADME/TOX analysis, with ZINC4085364 emerging as the most potent inhibitor of the VEB-1 β-lactamase.

Triacylglycerol lipases have been thoroughly characterized in mammals and microorganisms. By contrast, very little is known about plant lipases. In this investigation, a homology model of Arabidopsis thaliana lipase (NP_179126) was constructed using a human gastric lipase (PDB ID: 1HLG), as a template for model building. This model was then assessed for stereochemical quality and side chain environment. Natural substrates: tributyrin, trioctanoin and triolen were docked into the model to investigate ligand-substrate interaction.