Search results for: yeast inhibition

Authors: Young-Ran Song, Byeong-Uk Lim, Sang-Ho Baik

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This study was initiated in order to develop a method for soy sauce fermentation at low salt concentrations without decreasing quality. Soy sauce was fermented with the fermentation starter (meju) and different salt contents (8-14%, w/v) by inoculating two strains or not, in which Torulaspora delbrueckii and Pichia guilliermondii strains having different abilities to induce sterilizing effects or enhance flavor production were used. As the results, there were microbial and biochemical differences among prepared soy sauce. First, Staphylococcus and Enterococcus spp. in addition to Bacillus genus that is the most important bacteria in Korean fermented soy product were detected by salt reduction. However, application of yeast starters can inhibit the undesirable bacterial growth. Moreover, PCA bi-plots of major principal components on various biochemical parameters (final pH, total acidity, soluble sugar, reducing sugar, ethanol and 32 volatile flavor compounds) were drawn to demonstrate the physicochemical differences and similarities among the samples. It was confirmed that the soy sauce samples produced with different salt concentrations were clearly different since salt reduction induced low contents of acids, alcohols and esters with higher acidity. However despite low salt concentration, combining two different yeasts appeared to have similar characteristics to the high salt-fermented soy sauce with elevated concentrations of ethanol, some alcohols, and most ketones, hence resulted in a balance of more complex and richer flavors with a flavor profile pattern identical to that of high-salt.

Keywords: Soy sauce, low salt, fermentation, yeast.

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Authors: Hari Bezwada, Michelle Cheon, Ryan Divan, Hannah Escritor, Michelle Kagramian, Isha Korgaonkar, Maya MacAdams, Udgita Pamidigantam, Richard Pilny, Eleanor Race, Angadh Singh, Nathan Zhang, LeeAnn Nguyen, Fina Liotta

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Malaria is a deadly disease caused by the Plasmodium parasite, which continues to develop resistance to current antimalarial drugs. In this research project, the effectiveness of numerous thiazole derivatives was explored in inhibiting the PfPKG, a crucial part of the Plasmodium life cycle. This study involved the synthesis of six thiazole-derived amides to inhibit the PfPKG pathway. Nuclear Magnetic Resonance (NMR) spectroscopy and Infrared (IR) spectroscopy were used to characterize these compounds. Furthermore, AutoDocking software was used to predict binding affinities of these thiazole-derived amides in silico. In silico, compound 6 exhibited the highest predicted binding affinity to PfPKG, while compound 5 had the lowest affinity. Compounds 1-4 displayed varying degrees of predicted binding affinity. In-vitro, it was found that compound 4 had the best percent inhibition, while compound 5 had the worst percent inhibition. Overall, all six compounds had weak inhibition (approximately 30-39% at 10 μM), but these results provide a foundation for future drug discovery experiments.

Keywords: Medicinal Chemistry, Malaria, drug discovery, PfPKG, Thiazole, Plasmodium

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Authors: Yina A. Cifuentes Triana, Andrés M. Pinzón Velásco, Marío E. Velásquez Lozano

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In this work the sequencing and genome characterization of a natural isolate of Saccharomyces cerevisiae yeast (strain 202-3), identified with potential for the production of second generation ethanol from sugarcane bagasse hydrolysates is presented. This strain was selected because its capability to consume xylose during the fermentation of sugarcane bagasse hydrolysates, taking into account that many strains of S. cerevisiae are incapable of processing this sugar. This advantage and other prominent positive aspects during fermentation profiles evaluated in bagasse hydrolysates made the strain 202-3 a candidate strain to improve the production of second-generation ethanol, which was proposed as a first step to study the strain at the genomic level. The molecular characterization was carried out by genome sequencing with the Illumina HiSeq 2000 platform paired end; the assembly was performed with different programs, finally choosing the assembler ABYSS with kmer 89. Gene prediction was developed with the approach of hidden Markov models with Augustus. The genes identified were scored based on similarity with public databases of nucleotide and protein. Records were organized from ontological functions at different hierarchical levels, which identified central metabolic functions and roles of the S. cerevisiae strain 202-3, highlighting the presence of four possible new proteins, two of them probably associated with the positive consumption of xylose.

Keywords: cellulosic ethanol, Saccharomyces cerevisiae, genome sequencing, xylose consumption

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Authors: Chengyu Dong, Shao-Yuan Leu

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Cellulosic ethanol production from lignocellulosic biomass can reduce our reliance on fossil fuel, mitigate climate change, and stimulate rural economic development. The relative low ethanol production (60 g/L) limits the economic viable of lignocellulose-based biorefinery. The ethanol production can be increased up to 80 g/L by removing nearly all the non-cellulosic materials, while the capital of the pretreatment process increased significantly. In this study, a fed-batch prehydrolysis simultaneously saccharification and fermentation process (PSSF) was designed to converse the sulfite pretreated softwood (~30% residual lignin) to high concentrations of ethanol (80 g/L). The liquefaction time of hydrolysis process was shortened down to 24 h by employing the fed-batch strategy. Washing out the spent liquor with water could eliminate the inhibition of the pretreatment spent liquor. However, the ethanol yield of lignocellulose was reduced as the fermentable sugars were also lost during the process. Fed-batch prehydrolyzing the while slurry (i.e. liquid plus solid fraction) pretreated softwood for 24 h followed by simultaneously saccharification and fermentation process at 28 °C can generate 80 g/L ethanol production. Fed-batch strategy is very effectively to eliminate the “solid effect” of the high gravity saccharification, so concentrating the cellulose to nearly 90% by the pretreatment process is not a necessary step to get high ethanol production. Detoxification of the pretreatment spent liquor caused the loss of sugar and reduced the ethanol yield consequently. The tolerance of yeast to inhibitors was better at 28 °C, therefore, reducing the temperature of the following fermentation process is a simple and valid method to produce high ethanol production.

Keywords: cellulosic ethanol, sulfite pretreatment, Fed batch PSSF, temperature

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Authors: Nihar Ranjan, Derrick Watkins, Dev P. Arya

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Current methods in the study of antibiotic activity of ribosome targeted antibiotics are dependent on cell based bacterial inhibition assays or various forms of ribosomal binding assays. These assays are typically independent of each other and little direct correlation between the ribosomal binding and bacterial inhibition is established with the complementary assay. We have developed novel high-throughput capable assays for ribosome targeted drug discovery. One such assay examines the compounds ability to bind to a model ribosomal RNA A-site. We have also coupled this assay to other functional orthogonal assays. Such analysis can provide valuable understanding of the relationships between two complementary drug screening methods and could be used as standard analysis to correlate the affinity of a compound for its target and the effect the compound has on a cell.

Keywords: bacterial resistance, aminoglycosides, screening, drugs

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Authors: Elizabeth Loza-Valerdi, Victor Pardiñas-Rios, Arnulfo Pluma-Pluma, Andres Breton-Toral, Julio Cercado-Jaramillo

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The purification processes for mixtures of isomeric monosaccharides using industrial chromatographic methods poses a serious technical challenge. Mixtures of 2 or 3 monosaccharides are difficult to separate by strictly physical or chemical techniques. Differential fermentation by microbial cultures is an increasingly interesting way of selective enrichment in a particular kind of monosaccharides when a mixture of them is present in the solution, and only one has economical value. Osmotolerant yeast cultures provide an interesting source of biocatalysts for the selective catabolism of monosaccharides in media containing high concentrations of total soluble sugars. A collection of 398 yeast strains has been obtained using endemic and unique sources of fruit juices, industrial syrups, honey, and other high sugar content substrates, either natural or man made, products and by-products from Mexico. The osmotolerance of the strains was assessed by plate assay both in glucose (20-40-60%w/w). Strains were classified according to their osmotolerance in low, medium or highly tolerant to high glucose concentrations. The purified cultures were tested by their ability to growth in a solid plate media or liquid media of Yeas Nitrogen Base (YNB), added with specific monosaccharides as sole carbon source (glucose, galactose, lactose and fructose). Selected strains were subsequently tested in fermentation experiments with mixtures of two monosaccharides (galactose/glucose and glucose/fructose). Their ability to grow and selectively catabolize one monosaccharide was evaluated. Growth, fermentation activity and products of metabolism were determined by plate counts, CO2 production, turbidity and chromatographic analysis by HPLC. Selective catabolism of one monosaccharide in liquid media containing two monosaccharides was confirmed for 8 strains. Ion Exchange chromatographic processes were used in production of high fructose or galactose syrup. Laboratory scale processes for the production of fructose or galactose enriched syrups is now feasible, with important applications in food (like high fructose syrup as edulcorant) and fermentation technology (for GOS production).

Keywords: osmotolerant yeasts, selective metabolism, fructose syrup, GOS

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Authors: Hossein Rassi, Marjan Moradi Fard, Samaneh Niko

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Human papillomavirus type 16 and 18 are closely associated with the development of human cervical carcinoma, which is one of the most common causes of cancer death in women worldwide. At present, HPV type 18 accounts for about 34 % of all HPV infections in Iran and the most promising vaccine against HPV infection is based on the L1 major capsid protein. The L1 protein of HPV18 has the capacity to self-assemble into capsomers or virus-like particles (VLPs) that are non-infectious, highly immunogenic and allowing their use in vaccine production. The methylotrophic yeast Pichia pastoris is an efficient and inexpensive expression system used to produce high levels of heterologous proteins. In this study we expressed HPV18 L1 VLPs in P. pastoris. The gene encoding the major capsid protein L1 of the high-risk HPV type 18 was isolated from Iranian patient by PCR and inserted into pTG19-T vector to obtain the recombinant expression vector pTG19-HPV18-L1. Then, the pTG19-HPV18-L1 was transformed into E. coli strain DH5α and the recombinant protein HPV18 L1 was expressed under IPTG induction in soluble form. The HPV18 L1 gene was excised from recombinant plasmid with XhoI and EcoRI enzymes and ligated into the yeast expression vector pPICZα linearized with the same enzymes, and transformed into P. pastoris. Induction and expression of HPV18 L1 protein was demonstrated by BMGY/BMMY and RT PCR. The parameters for induced cultivation for strain in P. pastoris KM71 with HPV16L1 were investigated in shaking flask cultures. After induced cultivation BMMY (pH 7.0) medium supplemented with methanol to a final concentration of 1.0% every 24 h at 37 degrees C for 96 h, the recombinant produced 78.6 mg/L of L1 protein. This work offers the possibility for the production of prophylactic vaccine for cervical carcinoma by P. pastoris for HPV-18 L1 gene. The VLP-based HPV vaccines can prevent persistent HPV18 infections and cervical cancer in Iran. The HPV-18 L1 gene was expressed successfully in E.coli, which provides necessary basis for preparing HPV-18 L1 vaccine in human. Also, HPV type 6 L1 proteins expressed in Pichia pastoris will facilitate the HPV vaccine development and structure-function study.

Keywords: Pichia pastoris, L1 virus-like particles, human papillomavirus type 18, biotechnology

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Authors: Muhammad A. Ado, Intan S. Ismail, Hasanah M. Ghazali, Faridah Abas

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In this study, we have investigated the phytochemical constituents of soluble fractions of dichloromethane (DCM) of methanolic leaves extract of the Callicarpa maingayi. The phytochemicals investigation has resulted in the isolation of three triterpenoids (euscaphic acid (1), arjunic acid (2), and ursolic acid (3)) together with two flavones apigenin (4) and acacetin (5)), two phytosterols (stigmasterol 3-O-β-glycopyranoside (6) and sitosterol 3-O-β-glycopyranoside (7)), and one fatty acid (n-hexacosanoic acid (8)). Six (6) compounds isolated from this species were isolated for the first time (1, 2, 3, 4, 5, and 8). Their structures were elucidated and identified by spectral methods of one and two-dimensional NMR techniques, gas chromatography-mass spectrometry, and comparison with the previously reported literature. The biological activity of three compounds (1-3) was carried out on acetylcholinesterase inhibition activity. Compound (3) was found to displayed good inhibition against AChE with an IC₅₀ value of 21.5 ± 0.022 μM.

Keywords: acetylcholinesterase, Callicarpa maingayi, euscaphic acid, ursolic acid

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Authors: Ahmad Alazemi, M. Sherif El-Eskandrany, Mohamad Kishk, Thanyan AlOnaizi, Ahmad Alduweesh, Shorouq Abdullaleel

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Arc melting technique followed by top-down approach, using a high-energy ball milling technique were employed to synthesize nanocrystalline of Cu50(Zr50-xNix)50 (x = 0, 10, 20 and 30 at.%) powder particles. The end-products of the alloy powders obtained after 50 h of the ball milling time were uniform in composition and had spherical-like morphology with an average particle size of 0.75 µm in diameter. The powders, which consisted of nanocrystalline grains with an average grain size of 10 nm in diameter, were used as feedstock materials for double face coating of stainless (SUS304) sheets, using cold spraying process. The coating materials enjoyed nanocrystalline structure and uniform composition. Biofilms were grown on 20-mm2 SUS304 sheets coated coupons inoculated with 1.5 × 108 CFU ml−1 E. coli. Significant biofilm inhibition was recorded in the nanoparticles coated coupons in comparison to non-coated SUS304 coupon. In conclusion, this study demonstrates that formation of biofilms can be significantly inhibited by Cu-based alloys especially in case of high (Ni) content. The inhibition of biofilm formation by nanocrystalline powders of Cu-based provides a practical approach to achieve the inhibition of biofilms formed by an emerging pathogen.

Keywords: biofilm, Cu, E.coli, FE-HRTEM/EDS, nanomaterials, nanocrystalline

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Authors: Zoran Herceg, Višnja Stulić, Tomislava Vukušić, Anet Režek Jambrak

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High voltage electrical discharge is a new technology used for inactivation of pathogen microorganisms. Pathogen yeasts can cause diseases in humans if they are ingested. Nowadays new technologies have become the focus of researching all over the world. Rhodotorula is known as yeast that can cause diseases in humans. The aim of this study was to examine whether the high voltage electrical discharge treatment generated in gas phase has an influence on yeast reduction and recovery of Rhodotorula spp 74 in pure culture. Rhodotorula spp. 74 was treated in 200 mL of model solution. Treatment time (5 and 10 min), frequency (60 and 90 Hz) and injected gas (air or argon 99,99%) were changed. Titanium high voltage needle was used as high voltage electrode (positive polarity) through which air or argon was injected at the gas flow of 0.6 L/min. Experimental design and statistical analyses were obtained by Statgraphics Centurion software (StatPoint Technologies, Inc., VA, USA). The best inactivation rate 1.7 log10 reduction was observed after the 10 min of treatment, frequency of 90 Hz and injected air. Also with a longer treatment time inactivation rate was higher. After the 24 h recovery of treated samples was observed. Therefore the further optimization of method is needed to understand the mechanism of yeasts inactivation and cells recovery after the treatment. Acknowledgements: The authors would like to acknowledge the support by Croatian Science Foundation and research project ‘Application of electrical discharge plasma for preservation of liquid foods’.

Keywords: rhodotorula spp. 74, electrical discharge plasma, inactivation, stress response

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Authors: Houneïda Benbouzid, Houria Berrebbah, Mohammed-Réda Djebar

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The toxicological impacts of the increasing number of synthetic compounds present in the aquatic environment are assessed predominantly in laboratory studies where test organisms are exposed to a range of concentrations of single compounds. The bio-indicator Paramecium sp., characterized by a short life cycle, rapid multiplication and normal behavior that may be affected by the presence of pollutants. We therefore investigated the inhibitory effect of a newly synthesized acaricide: the chlorfenapyr tested at concentrations of 250, 300, and 350 µM on a pure culture of Paramecium sp. during 6 day. Paramecia treated with different concentrations of Chlorfenapyr illustrate strong inhibition of cell growth from the second day of treatment. Low levels of glutathione, increased glutathione S-transferase and the decrease in respiratory metabolism, recorded in the presence of different concentrations of Chlorfenapyr, involve the activation of detoxification system.

Keywords: Paramecium sp., chlorfenapyr, oxidative enzymes, detoxification

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Authors: Kok-Chong Yong

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Poly(butadiene-co-acrylonitrile)-polyaniline Dodecylbenzenesulfonate [NBR-PAni.DBSA] blends with useful electrical conductivity (up to 0.1 S/cm) were prepared and their corrosion inhibiting behaviours for carbon steel were successfully assessed for the first time. The level of compatibility between NBR and PAni.DBSA was enhanced through the introduction of 1.0 wt % hydroquinone. As found from both total immersion and electrochemical corrosion tests, NBR-PAni.DBSA blends with 10.0-30.0 wt% of PAni.DBSA content exhibited the best corrosion inhibiting behaviour for carbon steel, either in acid or artificial brine environment. On the other hand, blends consisting of very low and very high PAni.DBSA contents (i.e. ≤ 5.0 wt % and ≥ 40.0 wt %) showed significantly poorer corrosion inhibiting behaviour for carbon steel.

Keywords: conductive rubber, nitrile rubber, polyaniline, carbon steel, corrosion inhibition

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Authors: Parmjit S. Panesar, Rupinder Kaur, Ram S. Singh

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Enzymes are the biocatalysts which catalyze the biochemical processes and thus have a wide variety of applications in the industrial sector. β-Galactosidase (E.C. 3.2.1.23) also known as lactase, is one of the prime enzymes, which has significant potential in the dairy and food processing industries. It has the capability to catalyze both the hydrolytic reaction for the production of lactose hydrolyzed milk and transgalactosylation reaction for the synthesis of prebiotics such as lactulose and galactooligosaccharides. These prebiotics have various nutritional and technological benefits. Although, the enzyme is naturally present in almonds, peaches, apricots and other variety of fruits and animals, the extraction of enzyme from these sources increases the cost of enzyme. Therefore, focus has been shifted towards the production of low cost enzyme from the microorganisms such as bacteria, yeast and fungi. As compared to yeast and bacteria, fungal β-galactosidase is generally preferred as being extracellular and thermostable in nature. Keeping the above in view, the present study was carried out for the isolation of the β-galactosidase producing fungal strain from the food as well as the agricultural wastes. A total of more than 100 fungal cultures were examined for their potential in enzyme production. All the fungal strains were screened using X-gal and IPTG as inducers in the modified Czapek Dox Agar medium. Among the various isolated fungal strains, the strain exhibiting the highest enzyme activity was chosen for further phenotypic and genotypic characterization. The strain was identified as Rhizomucor pusillus on the basis of 5.8s RNA gene sequencing data.

Keywords: beta-galactosidase, enzyme, fungal, isolation

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Authors: Adebisi Adunola Demehin, Wanlaya Thamnarak, Jaruwan Chatwichien, Chatchakorn Eurtivong, Kiattawee Choowongkomon, Somsak Ruchirawat, Nopporn Thasana

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The epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein involved in cellular signalling processes and, its aberrant activity is crucial in the development of many cancers such as lung cancer. Selaginellaceae are fern allies that have long been used in Chinese traditional medicine to treat various cancer types, especially lung cancer. Biflavonoids, the major secondary metabolites in Selaginellaceae, have numerous pharmacological activities, including anti-cancer and anti-inflammatory. For instance, amentoflavone induces a cytotoxic effect in the human NSCLC cell line via the inhibition of PARP-1. However, to the best of our knowledge, there are no studies on biflavonoids as EGFR inhibitors. Thus, this study aims to investigate the EGFR inhibitory activities of biflavonoids isolated from Selaginella siamensis and Selaginella bryopteris. Amentoflavone, tetrahydroamentoflavone, sciadopitysin, robustaflavone, robustaflavone-4-methylether, delicaflavone, and chrysocauloflavone were isolated from the ethyl-acetate extract of the whole plants. The structures were determined using NMR spectroscopy and mass spectrometry. In vitro study was conducted to evaluate their cytotoxicity against A549, HEPG2, and T47D human cancer cell lines using the MTT assay. In addition, a target-based assay was performed to investigate their EGFR inhibitory activity using the kinase inhibition assay. Finally, a molecular docking study was conducted to predict the binding modes of the compounds. Robustaflavone-4-methylether and delicaflavone showed the best cytotoxic activity on all the cell lines with IC50 (µM) values of 18.9 ± 2.1 and 22.7 ± 3.3 on A549, respectively. Of these biflavonoids, delicaflavone showed the most potent EGFR inhibitory activity with an 84% relative inhibition at 0.02 nM using erlotinib as a positive control. Robustaflavone-4-methylether showed a 78% inhibition at 0.15 nM. The docking scores obtained from the molecular docking study correlated with the kinase inhibition assay. Robustaflavone-4-methylether and delicaflavone had a docking score of 72.0 and 86.5, respectively. The inhibitory activity of delicaflavone seemed to be linked with the C2”=C3” and 3-O-4”’ linkage pattern. Thus, this study suggests that the structural features of these compounds could serve as a basis for developing new EGFR-TK inhibitors.

Keywords: anticancer, biflavonoids, EGFR, molecular docking, Selaginellaceae

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Authors: Kabrambam D. Singh, Dinabandhu Sahoo, Yallappa Rajashekar

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Evolution has caused many insects to develop resistance to several synthetic insecticides. This problem along with the persisting concern regarding the health and environmental safety issues of the existing synthetic insecticides has urged the scientific fraternity to look for a new plant-based natural insecticide with inherent eco-friendly nature. Colocasia esculenta var. esculenta (L.) Schott (Araceae family) is widely grown throughout the South- East Asian Countries for its edible corms and leaves. Various physico-chemical and spectroscopic techniques (IR, 1H NMR, 13C NMR and Mass) were used for the isolation and characterization of isolated bioactive molecule named 2, 3-dimethylmaleic anhydride (3, 4-dimethyl-2, 5-furandione). This compound was found to be highly toxic, even at low concentration, against several storage grain pests when used as biofumigant. Experimental studies on the mode of action of 2, 3-dimethylmaleic anhydride revealed that the biofumigant act as inhibitor of acetylcholinesterase enzyme in cockroach and stored grain insects. The knockdown activity of bioactive compound is concurrent with in vivo inhibition of AChE; at KD99 dosage of bioactive molecule showed more than 90% inhibition of AChE activity in test insects. The molecule proved to affect the antioxidant enzyme system; superoxide dismutase (SOD), and catalase (CAT) and also found to decrease reduced glutathione (GSH) level in the treated insects. The above results indicate involvement of inhibition of AChE activity and oxidative imbalance as the potential mode of action of 2, 3-dimethylmaleic anhydride. In addition, the study reveals computational docking programs elaborate the possible interaction of 2, 3-dimethylmaleic anhydride with enzyme acetylcholinesterase (AChE) of Periplaneta americana. Finally, the results represent that toxicity of 2, 3-dimethylmaleic anhydride might be associated with inhibition of AChE activity and oxidative imbalance.

Keywords: 2, 3-dimethylmaleic anhydride, Colocasia esculenta var. esculenta (L.) Schott, Biofumigant, acetylcholinesterase, antioxidant enzyme, molecular docking

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Authors: Iman Adnan Annon, Kadhim F. Alsultan

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This study investigate the internal corrosion of low carbon steel pipelines in the crude oil, as well as prepare and use natural and locally available plant as a natural corrosion inhibiter, the nature extraction achieved by two types of solvents in order to show the solvent effect on inhibition process, the first being distilled water and the second is diethyl ether. FT-IR spectra and using a chemical reagents achieved to detection the presence of many active groups and the presence of tannins, phenols, and alkaloids in the natural extraction. Some experiments were achieved to estimate the performance of a new inhibitor, one of these tests include corrosion measurement by simple immersion in crude oil within and without inhibitors which added in different amounts 30,40,50and 60 ppm at tow temperature 300 and 323k, where the best inhibition efficiencies which get when added the inhibitors in a critical amounts or closest to it, since for the aqueous extract (EB-A) the inhibition efficiency reached (94.4) and (86.71)% at 300 and 323k respectively, and for diethyl ether extract (EB-D) reached (82.87) and (84.6)% at 300 and 323k respectively. Optical microscopy examination have been conducted to evaluate the corrosion nature where it show a clear difference in the topography of the immersed samples surface after add the inhibitors at two temperatures. The results show that the new corrosion inhibitor is not only equivalent to a chemical inhibitor but has greatly improvement properties such as: high efficiency, low cost, non-toxic, easily to produce, and nonpolluting as compared with chemical inhibitor.

Keywords: corrosion in pipeline, inhibitors, crude oil, carbon steel, types of solvent

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Authors: G. Ozturk, B. Demirci

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It is well known that essential oils used for therapeutic purposes for many years. In this study, five different Pharmacopoeia grade essential oils (Achillea millefolium L., Pimpinella anisum L., Matricaria recutita L., Eucalyptus globulus L., Salvia officinalis L.) which obtained from commercial sources were evaluated for chemical compositions, synergistic antimicrobial activities, and lipoxygenase enzyme inhibitions. Volatile components were determined by gas chromatography/flame ionization detector and gas chromatography/mass spectrometer, simultaneously. The potential antimicrobial activity of essential oils was tested against oral pathogenic standard strains such as Streptococcus mutans, Streptococcus sanguinis, Staphylococcus aureus, Corynebacterium striatum, Candida albicans and Candida krusei by broth microdilution methods. Ciprofloxacin and ketoconazole were used positive controls. It has been observed that the essential oils tested have average inhibitory antimicrobial activity against oral pathogens with a Minimum Inhibition Concentration of 20-0.625 mg/mL. The active essential oils have been combined with antibiotics and synergistic effects have been evaluated by Checkerboard method. ƩFIC values were determined. In combination with antibiotics M. recutita essential oil has been shown to have a synergistic effect against S. aureus in combination with tetracycline (ƩFIC 0.46). In addition, 5-LOX inhibitory activity was measured by modifying the spectrophotometric method developed by Baylac and Racine. As a result, 5-LOX % inhibition of S. officinalis, E. globulus and M. recutita were calculated as 34.0 ± 6.66, 72.7 ± 2.78 and 27.7 ± 0.60, respectively.

Keywords: antimicrobial activity, essential oils, synergistic activity, 5-lipoxygenase inhibition

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Authors: Shanakr Bhattarai, V. S. Tiwari, Barak Akabayov

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The plummeting number of infections and death is due to the development of drug-resistant bacteria. In addition, the number of approved antibiotic drugs by the Food and Drug Administration (FDA) is insufficient. Therefore, developing new drugs and finding novel targets for central metabolic pathways in bacteria is urgently needed. One of the promising targets is DNA replication machinery which consists of many essential proteins and enzymes. DnaG primase is an essential enzyme and a central part of the DNA replication machinery. DnaG primase synthesizes short RNA primers that initiate the Okazaki fragments by the lagging strand DNA polymerase. Therefore, it is reasonable to assume that inhibition of primase activity will stall DNA replication and prevent bacterial proliferation. We did the expression and purification of eight different bacterial DnaGs (Mycobacterium tuberculosis(Mtb), Bacillus anthracis (Ba), Mycobacterium smegmatis (Msmeg), Francisella tularencis (Ft), Vibrio cholerae (Vc) and Yersinia pestis (Yp), Staphylococcus aureus(Saureus), Escherichia coli(Ecoli)) followed by the radioactive activity assay. After obtaining the pure and active protein DnaG, we synthesized the inhibitors for them. The inhibitors were divided into five different groups, each containing five molecules, and the cocktail inhibition assay was performed against each DnaGs. The groups of molecules inhibiting the DnaGs were further tested with individual molecules belonging to inhibiting groups. Each molecule showing inhibition was titrated against the corresponding DnaGs to find IC50. We got a molecule(VS167) that acted as broad inhibitors, inhibiting all eight DnaGs. Molecules VS180 and VS186 inhibited seven DnaGs (except Saureus). Similarly, two molecules(VS 173, VS176) inhibited five DnaGs (Mtb, Ba, Ft, Yp, Ecoli). VS261 inhibited four DnaGs (Mtb, Ba, Ft, Vc). MS50 inhibited Ba and Vc DnaGs. And some of the inhibitors inhibited only one DnaGs. Thus we found the broad and specific inhibitors for different bacterial DnaGs, and their Structure-activity analysis(SAR) was done. Further, We tried to explain the similarities among the enzyme DnaGs from different bacteria based on their inhibition pattern.

Keywords: DNA replication, DnaG, okazaki fragments, antibiotic drugs

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Authors: Ganesh Dattatraya Saratale, Min Kyu Oh

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Rice straw is one of the most abundant lignocellulosic waste materials and its annual production is about 731 Mt in the world. This study treats the subject of effective utilization of this waste biomass for biofuels production. We have showed a comparative assessment of numerous pretreatment strategies for rice straw, comprising of major physical, chemical and physicochemical methods. Among the different methods employed for pretreatment alkaline pretreatment in combination with sodium chlorite/acetic acid delignification found efficient pretreatment with significant improvement in the enzymatic digestibility of rice straw. A cellulase dose of 20 filter paper units (FPU) released a maximum 63.21 g/L of reducing sugar with 94.45% hydrolysis yield and 64.64% glucose yield from rice straw, respectively. The effects of different pretreatment methods on biomass structure and complexity were investigated by FTIR, XRD and SEM analytical techniques. Finally the enzymatic hydrolysate of rice straw was used for ethanol production using developed Saccharomyces cerevisiae SR8. The developed yeast strain enabled efficient fermentation of xylose and glucose and produced higher ethanol production. Thus development of bioethanol production from lignocellulosic waste biomass is generic, applicable methodology and have great implication for using ‘green raw materials’ and producing ‘green products’ much needed today.

Keywords: rice straw, pretreatment, enzymatic hydrolysis, FPU, Saccharomyces cerevisiae SR8, ethanol fermentation

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Authors: Khalida Boutemak, Nasssima Benali, Nadji Moulai-Mostefa

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Effect of enzyme on the yield and chemical composition of Artemisia campestris essential oil is reported in the present study. It was demonstrated that enzyme facilitated the extraction of essential oil with increase in oil yield and did not affect any noticeable change in flavour profile of the volatile oil. Essential oil was tested for antibacterial activity using Escherichia coli; which was extremely sensitive against control with the largest inhibition (29mm), whereas Staphylococcus aureus was the most sensitive against essential oil obtained from enzymatic pre-treatment with the largest inhibition zone (25mm). The antioxidant activity of the essential oil with hemicellulase pre-treatment (EO2) and control sample (EO1) was determined through reducing power. It was significantly lower than the standard drug (vitamin C) in this order: vitamin C˃EO2˃EO1.

Keywords: Artemisia campestris, enzyme pre-treatment, hemicellulase, antibacterial activity, antioxidant activity

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Authors: Barrera C. Monserrat, Sierra-Alvarez Reyes, Pat-Espadas Aurora, Moreno Andrade Ivan

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Antimony is a toxic and carcinogenic metalloid considered a pollutant of priority interest by the United States Environmental Protection Agency. It is present in the environment in two oxidation states: antimonite (Sb (III)) and antimony (Sb (V)). Sb (III) is toxic to several aquatic organisms, but the potential inhibitory effect of Sb species for microorganisms has not been extensively evaluated. The fate and possible toxic impact of antimony on aerobic and anaerobic wastewater treatment systems are unknown. For this reason, the objective of this study was to evaluate the microbial toxicity of Sb (V) and Sb (III) in aerobic and anaerobic environments. Sb(V) and Sb(III) were used as potassium hexahydroxoantimonate (V) and potassium antimony tartrate, respectively (Sigma-Aldrich). The toxic effect of both Sb species in anaerobic environments was evaluated on methanogenic activity and the inhibition of hydrogen production of microorganisms from a wastewater treatment bioreactor. For the methanogenic activity, batch experiments were carried out in 160 mL serological bottles; each bottle contained basal mineral medium (100 mL), inoculum (1.5 g of VSS/L), acetate (2.56 g/L) as substrate, and variable concentrations of Sb (V) or Sb (III). Duplicate bioassays were incubated at 30 ± 2°C on an orbital shaker (105 rpm) in the dark. Methane production was monitored by gas chromatography. The hydrogen production inhibition tests were carried out in glass bottles with a working volume of 0.36 L. Glucose (50 g/L) was used as a substrate, pretreated inoculum (5 g VSS/L), mineral medium and varying concentrations of the two species of antimony. The bottles were kept under stirring and at a temperature of 35°C in an AMPTSII device that recorded hydrogen production. The toxicity of Sb on aerobic microorganisms (from a wastewater activated sludge treatment plant) was tested with a Microtox standardized toxicity test and respirometry. Results showed that Sb (III) is more toxic than Sb (V) for methanogenic microorganisms. Sb (V) caused a 50% decrease in methanogenic activity at 250 mg/L. In contrast, exposure to Sb (III) resulted in a 50% inhibition at a concentration of only 11 mg/L, and an almost complete inhibition (95%) at 25 mg/L. For hydrogen-producing microorganisms, Sb (III) and Sb (V) inhibited 50% of this production with 12.6 mg/L and 87.7 mg/L, respectively. The results for aerobic environments showed that 500 mg/L of Sb (V) do not inhibit the Allivibrio fischeri (Microtox) activity or specific oxygen uptake rate of activated sludge. In the case of Sb (III), this caused a loss of 50% of the respiration of the microorganisms at concentrations below 40 mg/L. The results obtained indicate that the toxicity of the antimony will depend on the speciation of this metalloid and that Sb (III) has a significantly higher inhibitory potential compared to Sb (V). It was shown that anaerobic microorganisms can reduce Sb (V) to Sb (III). Acknowledgments: This work was funded in part by grants from the UA-CONACYT Binational Consortium for the Regional Scientific Development and Innovation (CAZMEX), the National Institute of Health (NIH ES- 04940), and PAPIIT-DGAPA-UNAM (IN105220).

Keywords: aerobic inhibition, antimony reduction, hydrogen inhibition, methanogenic toxicity

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Authors: A. Y. Benabdellah, W. Lakhdari, A. Dahliz, Y. Bouchikh, A. Soud, R. M'lik, H. Hammi

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The direct comparison tests on the culture medium, between Trichoderma sp. and Fusarium oxysporum f. sp. radicis-lycopersici revealed that the latest one could inhibit the growth of F. oxysporum mycelial over than 40% compared to the control and that after four days of incubation at 26° C. Moreover, beyond this period and at the end of six days, Trichoderma sp. invading the colonies of F. oxysporum on what it sporule, thus revealing its power is highly myco-parasitic. Almost similar results were obtained against Alternaria solani is also a pathogen which is not causing a lot of damage, but we found it more sensitive to Trichoderma sp. with a percentage of inhibition more than 50%. So due to the in vitro test of Trichoderma sp. against these aggressive pathogens by direct contact has been found that can inhibit their mycelial growth with high speed and a high inhibition rate.

Keywords: Trichoderma sp., Fusarium oxysporum f. sp. radicis-lycopersici, Alternaria solani, biological control, antagonist

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Authors: M. Javanmard

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This study was aimed at analyzing the effects of packaging (MAP) and preservation conditions on the packaged fresh walnut kernel quality. The central composite plan was used for evaluating the effect of oxygen (0–10%), carbon dioxide (0-10%), and temperature (4-26 °C) on qualitative characteristics of walnut kernels. Also, the response level technique was used to find the optimal conditions for interactive effects of factors, as well as estimating the best conditions of process using least amount of testing. Measured qualitative parameters were: peroxide index, color, decreased weight, mould and yeast counting test, and sensory evaluation. The results showed that the defined model for peroxide index, color, weight loss, and sensory evaluation is significant (p < 0.001), so that increase of temperature causes the peroxide value, color variation, and weight loss to increase and it reduces the overall acceptability of walnut kernels. An increase in oxygen percentage caused the color variation level and peroxide value to increase and resulted in lower overall acceptability of the walnuts. An increase in CO₂ percentage caused the peroxide value to decrease, but did not significantly affect other indices (p ≥ 0.05). Mould and yeast were not found in any samples. Optimal packaging conditions to achieve maximum quality of walnuts include: 1.46% oxygen, 10% carbon dioxide, and temperature of 4 °C.

Keywords: shelled walnut, MAP, quality, storage temperature

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Authors: Ambrish Singh

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The corrosion inhibition performance of pyran (AP) and benzimidazole (BI) derivatives on J55 steel in 3.5% NaCl solution saturated with CO₂ was investigated by electrochemical, weight loss, surface characterization, and theoretical studies. The electrochemical studies included electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM), and electrochemical frequency modulation trend (EFMT). Surface characterization was done using contact angle, scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. DFT and molecular dynamics (MD) studies were done using Gaussian and Materials Studio softwares. All the studies suggested the good inhibition by the synthesized inhibitors on J55 steel in 3.5% NaCl solution saturated with CO₂ due to the formation of a protective film on the surface. Molecular dynamic simulation was applied to search for the most stable configuration and adsorption energies for the interaction of the inhibitors with Fe (110) surface.

Keywords: corrosion, inhibitor, EFM, AFM, DFT, MD

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Authors: Hue Dinh, Binh Nguyen, Vivian Mendez, Phillip W. Taylor, Fleur Ponton

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Better understanding of how parental diet affects offspring traits is an important ecological and evolutionary question. In this study, we explored how maternal diet influences offspring physiology and resistance to infection using Bactrocera tryoni (Q-fly) as a system model. Female Q-flies were fed one of six single diets varying in their yeast-to-sugar ratio yielding six protein-to-carbohydrate ratios. As controls, we used females that were given a choice between yeast and sugar. Males were reared on a choice diet and allowed to mate with females 14 days post-emergence. Results showed that while maternal diet does not influence offspring developmental time, it has a strong effect on larval body weight. Mother fed either high-protein or high-sugar diet produced larger progeny. By challenging offspring with the bacterium Serratia marcescens, we found that female offspring from mothers fed high-sugar diet survived better the infection compared to those from mothers fed low-sugar diet. In contrast, male offspring produced by mother fed high-protein diet showed better resistance to the infection compared to those produced by mother fed low-protein diet. These results suggested sex-dependent transgenerational effects of maternal nutrition on offspring physiology and immunity.

Keywords: bacterial infection, Bactrocera tryoni, maternal diet, offspring, Serretia marcescens

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Authors: Pao-Huei Chen, Shu-Mei Lin, Yih-Ming Weng, Zer-Ran Yu, Be-Jen Wang

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Pancreatic α-amylase and intestinal α-glucosidase are the critical enzymes for the breakdown of complex carbohydrates into di- or mono-saccharide, which play an important role in modulating postprandial blood sugars. Angiotensin converting enzyme (ACE) converts inactive angiotensin-I into active angiotensin-II, which subsequently increase blood pressure through triggering vasoconstriction and aldosterone secretion. Thus, inhibition of carbohydrate-digestion enzymes and ACE will help the management of blood glucose and blood pressure, respectively. Studies showed Pleurotus citrinopileatus (PC), an edible mushroom and commonly cultured in oriental countries, exerted anticancer, immune improving, antioxidative, hypoglycemic and hypolipidemic effects. Previous studies also showed various molecular weights (MW) fractioned from extracts may affect biological activities due to varying contents of bioactive components. Thus, the objective of this study is to investigate the in vitro antioxidant, hypoglycemic and hypotenstive effects and distribution of active compounds of various MWs of cold water extract from P. citrinopileatus (CWEPC). CWEPC was fractioned into four various MW fractions, PC-I (＜1 kDa), PC-II (1-3.5 kDa), PC-III (3.5-10 kDa), and PC-IV (＞10 kDa), using an ultrafiltration system. The physiological activities, including antioxidant activities, the inhibition capabilities of pancreatic α-amylase, intestinal α-glucosidase, and hypertension-linked ACE, and the active components, including polysaccharides, protein, and phenolic contents, of CWEPC and four fractions were determined. The results showed that fractions with lower MW exerted a higher antioxidant activity (p<0.05), which was positively correlated to the levels of total phenols. In contrast, the inhibition effects on the activities of α-amylase, α-glucosidase, and ACE of PC-IV fraction were significantly higher than CWEPC and the other three low MW fractions (< 10 kDa), which was more related to protein contents. The inhibition capability of CWEPC and PC-IV on α-amylase activity was 1/13.4 to 1/2.7 relative to that of acarbose (positive control), respectively. However, the inhibitory ability of PC-IV on α-glucosidase (IC50 = 0.5 mg/mL) was significantly higher than acarbose (IC50 = 1.7 mg/mL). Kinetic data revealed that PC-IV fraction followed a non-competitive inhibition on α-glucosidase activity. In conclusion, the distribution of various bioactive components contribute to the functions of different MW fractions on oxidative stress prevention, and blood pressure and glucose modulation.

Keywords: α-Amylase, angiotensin converting enzyme, α-Glucosidase, Pleurotus citrinopileatus

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Authors: Mohit Wadhawan, Sushma Rathaur

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Lymphatic filariasis, also called elephantiasis is a tropical disease afflicting over 120 million people in 81 countries worldwide. Existing anti filarial drugs are effective against the larval stages of filarial parasites which call for an urgent need of drugs which are macrofilaricidal. Identification of molecular targets crucial for survival of filarial parasites is a prerequisite for drug designing. Prolyl oligopeptidase (POP) is one such crucial enzyme involved in the maturation and degradation of neuropeptides and peptide hormones. We have identified this peptidase in the bovine filarial parasite, Setaria cervi. Effect of inhibition of POP on the proteome profile of filarial parasite has been discussed in this study. Filarial parasites were exposed to Z-pro-prolinal (ZPP), a specific POP inhibitor for 8 h and the motility and viability of the parasites was observed. It significantly reduced the motility and viability of the parasites. To study the proteome profile, the cytosolic, endoplasmic reticulum (ER) and mitochondrial extracts of the adult female parasites were subjected to 2-dimensional electrophoresis. As analyzed by the PD-Quest software, the ZPP caused the alteration in the different subcellular proteins, and the significantly altered proteins were identified using MALDI-MS/MS spectrometry. The major proteins identified were found to play important role in diverse biological functions like signaling, redox regulation, energy metabolism, stress response, and cytoskeleton formation. Moreover, we found upregulation in the calcium binding proteins such as calreticulin, calponin, and calpain-6 suggesting that POP inhibition regulates calcium release. This relates to earlier reports that POP plays non-catalytic role in inositol 1,4,5-trisphosphate (IP3) signaling inducing release of calcium from ER. Taken together, the data demonstrated that inhibition of prolyl oligopeptidase alter the overall proteome signifying its role in survival of the filarial parasites. Thus this study provides a basis for the use of POP as a chemotherapeutic target for the treatment of lymphatic filariasis.

Keywords: lymphatic filariasis, setaria cervi, prolyl oligopeptidase, proteomics

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Authors: Chengcao Sun, Cuili Yang, Shujun Li, Ruilin Xue, Yongyong Xi, Liang Wang, Dejia Li

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Backgrounds: A few lines of evidence show that Sulforaphane (SFN) has anti-fibrosis effect in liver tissue via Nrf2-mediated inhibition of TGF-β/Smad signaling. However, its effects on muscular dystrophic fibrosis remain unknown. This work was undertaken to evaluate the effects of SFN on fibrosis in dystrophic muscle. Methods: 3-month-old male mdx mice were treated with SFN by gavage (2 mg/kg body weight per day) for 3 months. Gastrocnemius, tibial anterior and triceps brachii muscles were collected for related analysis. Fibrosis in skeletal muscles was analyzed by Sirius red staining. Histology and morphology of skeletal muscles were investigated by H&E staining. Moreover, the expressions of Nrf2, NQO1, HO-1, and TGF-β/Smad signaling pathway were detected by western blot, qRT-PCR, immunohistochemistry and immunofluorescence assays. Results: Our results demonstrated that SFN treatment significantly decreased and improved morphological features in mdx muscles. Moreover, SFN increased the expression of muscle phase II enzymes NQO1 and HO-1 and significantly decreased the expression of TGF-β1，p-smad2, p-smad3, α-SMA, fibronectin, collagen I, PAI-1, and TIMP-1 in Nrf2 dependent manner. Additionally, SFN significantly decreased the expression of CD45 and TNF-α. Conclusions: Collectively, these results show that SFN can ameliorate muscle fibrosis in mdx mice by Nrf2-induced inhibition of TGF-β/Smad signaling pathway, which indicate Nrf2 may be useful for the treatment of muscular dystrophy.

Keywords: sulforaphane, Nrf2, TGF-β/smad signaling, duchenne muscular dystrophy, fibrosis

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Authors: Naoual Boussoualim, Hayat Trabsa, Iman Krache, Lekhmici Arrar, Abderrahmane Baghiani

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Resistance to antibiotics has emerged following their widespread use; the important mechanism of beta-lactam resistance in bacteria is the production of beta-lactamase. In order to find new bioactive beta-lactamase inhibitors, this study investigated the inhibition effect of the extracts of Anchusa azurea (AA) on a beta-lactamase from Bacillus cereus. The extracts exerted inhibitory effects on beta-lactamase in a dose-dependent manner, the results showed that the crude extract (BrE) and the ethyl acetate extract (AcE) of Anchusa azurea showed a very high inhibitory activity at a concentration of 10 mg, the percentage of inhibition was between 58% and 68%. Not all extracts were as potent as the original inhibitors such as clavulanic acid, the isolation and the structural elucidation of the active constituents in these extracts will provide useful means in the development of beta -lactamase inhibitors.

Keywords: Anchusa azurea, natural product, resistance, antibiotics, beta-lactamase, inhibitors

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Authors: Shimaa A. Higazy, Olfat E. El-Azabawy, Ahmed M. Al-Sabagh, Notaila M. Nasser, Eman A. Khamis

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In this work, two novel Schiff base polymers (PSB1 and PSB₂) with extra-high protective barrier features were facilely prepared via Polycondensation reactions. They were applied for the first time as effective corrosion inhibitors in the sour corrosive media of petroleum environments containing hydrogen sulfide (H₂S) gas. For studying the polymers' inhibitive action on the carbon steel, numerous corrosion testing methods including potentiodynamic polarization (PDP), open circuit potential, and electrochemical impedance spectroscopy (EIS) have been employed at various temperatures (298-328 K) in the oil wells formation water with H₂S concentrations of 100, 400, and 700 ppm as aggressive media. The activation energy (Ea) and other thermodynamic parameters were computed to describe the mechanism of adsorption. The corrosion morphological traits and steel samples' surfaces composition were analyzed by field emission scanning electron microscope and energy dispersive X-ray analysis. The PSB2 inhibited sour corrosion more effectively than PSB1 when subjected to electrochemical testing. The 100 ppm concentration of PSB2 exhibited 82.18 % and 81.14 % inhibition efficiencies at 298 K in PDP and EIS measurements, respectively. While at 328 K, the inhibition efficiencies were 61.85 % and 67.4 % at the same dosage and measurements. These poly Schiff bases exhibited fascinating performance as corrosion inhibitors in sour environment. They provide a great corrosion inhibition platform for the sustainable future environment.

Keywords: schiff base polymers, corrosion inhibitors, sour corrosive media, potentiodynamic polarization, H₂S concentrations

Procedia PDF Downloads 63