Najla haddaji - Academia.edu (original) (raw)

Papers by Najla haddaji

Research paper thumbnail of Identification of a putative kinase interacting domain in the durum wheat catalase 1 (TdCAT1) protein

Research paper thumbnail of GC/MS Profiling, Antibacterial, Anti-Quorum Sensing, and Antibiofilm Properties of Anethum graveolens L. Essential Oil: Molecular Docking Study and In-Silico ADME Profiling

Plants

Anethum graveolens L. has been known as an aromatic, medicinal, and culinary herb since ancient t... more Anethum graveolens L. has been known as an aromatic, medicinal, and culinary herb since ancient times. The main purpose of this study was to determine the chemical composition, antibacterial, antibiofilm, and anti-quorum sensing activities of the essential oil (EO) obtained by hydro-distillation of the aerial parts. Twelve components were identified, representing 92.55% of the analyzed essential oil. Limonene (48.05%), carvone (37.94%), cis-dihydrocarvone (3.5%), and trans-carvone (1.07%) were the main identified constituents. Results showed that the obtained EO was effective against eight bacterial strains at different degrees. Concerning the antibiofilm activity, limonene was more effective against biofilm formation than the essential oil when tested using sub-inhibitory concentrations. The results of anti-swarming activity tested against P. aeruginosa PAO1 revealed that A. graveolens induced more potent inhibitory effects in the swarming behavior of the PAO1 strain when compared ...

Research paper thumbnail of Genome-Wide Identification and Expression Profiling of Pathogenesis-Related Protein 1 (PR-1) Genes in Durum Wheat (Triticum durum Desf.)

Plants

Pathogen-related proteins (PRs) are diversified proteins with a low molecular weight implicated i... more Pathogen-related proteins (PRs) are diversified proteins with a low molecular weight implicated in plant response to biotic and abiotic stress as well in regulating different functions in plant maturation. Interestingly, no systematical study has been conducted in durum wheat (Triticum turgidum subsp. durum). In the present study, 12 PR-1 genes encoding a CAP superfamily domain were identified in the genome of Triticum turgidum subsp. durum, which is an important cereal, using in silico approaches. Additionally, phylogenetic analysis showed that the PR-1 genes were classified into three groups based on their isoelectric point and the conserved motif domain. Moreover, our analysis showed that most of the TdPR-1 proteins presented an N-terminal signal peptide. Expression patterns analysis showed that the PR-1 gene family presented temporal and spatial specificity and was induced by different abiotic stresses. This is the first report describing the genome-scale analysis of the durum w...

Research paper thumbnail of Characterization of palm date varieties (Phoenix dactylifera L.) growing in Saudi Arabia: Phenotypic diversity estimated by fruit and seed traits

Notulae Botanicae Horti Agrobotanici Cluj-Napoca

In order to determine the variation and the degree of diversity among the most well-known Saudi d... more In order to determine the variation and the degree of diversity among the most well-known Saudi date palm (Phoenix dactylifera L.), this study applied various widely detectible fruit and seed features. The properties of the fruit and seeds were described using ten phenotypic traits. Eighteen date palm varieties from six production sites were used in this study (Ḥaʼil, Al-Madina, Al-Hassa, Al-Qassim, Kharaj, Najran). The data was analysed by Pearson r correlation. The principal components analysis (PCA) and UPGMA clustering were used to analyse the data set. According to PCA, the results showed significant variation among the analysed varieties. Our data shows that seed ratio varies among all varieties. The mean seed weight ratio varies between 4 and 13%. Varieties ‘Raziz’, ‘Lubab’ and ‘Wasily’ demonstrate higher seed ratio (over 10%). Whereas, Fankha depicts a 5 and 4% fresh and dry seed ratio. The statistical analysis indicates that the seed ratio in all 18 varieties is comparable ...

Research paper thumbnail of In Vitro Characterization of Limosilactobacillus reuteri Lac Ib01 (OL468126.1) Isolated from Traditional Sheep Dry Sausage and Evaluation of the Activity of Arthrospira platensis or Phycocyanin on Its Growth-Promoting Ability

Fermentation

The positive impact of probiotic strains on human health is more evident than ever. To achieve th... more The positive impact of probiotic strains on human health is more evident than ever. To achieve the beneficial health effects and desirable functional properties of probiotics, sufficient numbers of these microorganisms must reach the intestinal tract with high survival rates. The purpose of this study was to identify and characterize a novel strain of Limosilactobacillus reuteri isolated from traditional sheep dry sausage and evaluate its growth-promoting ability with the addition of Arthrospira platensis or phycocyanin extract. In vitro experimental approaches were conducted to determine the physiological features of the candidate probiotic isolate, including biochemical identification, 16S rRNA gene sequencing, tolerance assays to acid and bile salts, antimicrobial activities, adherence ability, and antiproliferative assays. The effects of A. platensis or phycocyanin (0, 1, 5, and 8 mg/mL) on the growth of probiotic cultures were studied after 0, 24, 48, and 72 h. Our results show...

Research paper thumbnail of Development of Nanotechnology-Based Drug Delivery Systems for Controlling Clinical Multidrug-Resistant Staphylococcus aureus and Escherichia coli Associated with Aerobic Vaginitis

Pharmaceutics

The growing prevalence of resistance to antibiotics potentially makes Escherichia coli and Staphy... more The growing prevalence of resistance to antibiotics potentially makes Escherichia coli and Staphylococcus aureus serious pathogens, necessitating the development of new antimicrobial agents. We extracted crude biosurfactants from a potential probiotic Bacillus spp. to control pathogenic bacteria associated with aerobic vaginal infection. Using nanotechnology formulations, we developed nanoemulsions based on biosurfactants at different concentrations (1% and 3.33%). The results showed that these nanoemulsions were stable, with a weighted index of 0.3, and demonstrated broad-spectrum antibacterial activity against Escherichia coli and Staphylococcus aureus, with MICs ranging between 1.25 and 4 mg/mL. Additionally, the nanoemulsions exhibited interesting antibiofilm effects. All strains became more sensitive to the antibiotics to which they were resistant because of various biosurfactant formulations combined with antibiotics. Lower concentrations of BNE1% and 3.33% were still more eff...

Research paper thumbnail of Biosurfactants as inhibitors of the adhesion of pathogenic bacteria

Emirates Journal of Food and Agriculture

Biosurfactants have gained more attention in the past decade as possible medical resources. They ... more Biosurfactants have gained more attention in the past decade as possible medical resources. They are useful therapeutic agents againstmany infections because of their antibacterial, antifungal, and antiviral properties. Additionally, the anti-adherent activities of thesecompounds counter to a number of pathogens suggest that they could be useful as an anti-adherent coating for medical inserts, helpingto prevent infections in hospitals without the use of chemicals. This study aims to investigate the antiadhesive activities of biosurfactantsextracted from Lactobacillus brevis and Bacillus sp. against seven clinical pathogens. Biosurfactants at different concentrations wereapplied to polystyrene surfaces, and then the attachment of pathogenic strains was evaluated. The adhesion of microbes to n-hexadecanewas also studied. As a result, the bacterial strains with 50 mg/ml of Lactobacillus brevis biosurfactant displayed a 69–73% reduction inadhesion. In contrast to the first biosurfactant...

Research paper thumbnail of Identification and Expression Profiling of Two Saudi Arabia Catalase Genes from Wheat and Barley in Response to Abiotic and Hormonal Stresses

Antioxidants

Catalase is a crucial enzyme in antioxidant defense systems protecting eukaryotes from oxidative ... more Catalase is a crucial enzyme in antioxidant defense systems protecting eukaryotes from oxidative stress. These proteins are present in almost all living organisms and play important roles in controlling plant responses to biotic and abiotic stresses by catalyzing the decomposition of H2O2. Despite their importance, little is known about their expression in the majority of monocotyledonous species. Here, we isolated and characterized two novel catalase genes from Triticum turgidum and Hordeum vulgare, designated as TtCAT1 and HvCAT1, respectively. Phylogenetic analysis revealed that TtCAT1 and HvCAT1 presented 492 aa and shared an important identity with other catalase proteins belonging to subfamily 1. Using bioinformatic analysis, we predicted the 3D structure models of TtCAT1 and HvCAT1. Interestingly, analysis showed that the novel catalases harbor a peroxisomal targeting signal (PTS1) located at their C-terminus portion, as shown for other catalase proteins. In addition, this mo...

Research paper thumbnail of Comparative Study of Antibacterial, Antibiofilm, Antiswarming and Antiquorum Sensing Activities of Origanum vulgare Essential Oil and Terpinene-4-ol against Pathogenic Bacteria

Life

Essential oils from aromatic and medicinal plants have many bioactive compounds known for their i... more Essential oils from aromatic and medicinal plants have many bioactive compounds known for their important biological activities mainly their antibacterial effects. Here we evaluated qualitatively and quantitatively the biofilm formation capability of pathogenic bacterial strains (n = 8). Then, we investigated the antibacterial, antibiofilm, antiquorum-sensing, and antiswarming efficacy of Origanum vulgare essential oil (EO) and terpinene-4-ol. Our results revealed that EO exhibited a more potent inhibitory effect against the tested strains. While the terpinene-4-ol was found to be more effective against developed Staphylococcus aureus biofilm. Regarding the anti quorum-sensing activity, we noticed that O. vulgare displayed better inhibition percentages in violacein production even at a low concentration (MIC/4). Additionally, this EO showed better inhibition of Pseudomonas aeruginosa PAO1 migration in comparison with the terpinene-4-ol. Our findings revealed that using pure O. vulga...

Research paper thumbnail of Control of Multidrug-Resistant Pathogenic Staphylococci Associated with Vaginal Infection Using Biosurfactants Derived from Potential Probiotic Bacillus Strain

Fermentation

Biosurfactants exhibit antioxidant, antibacterial, antifungal, and antiviral activities. They can... more Biosurfactants exhibit antioxidant, antibacterial, antifungal, and antiviral activities. They can be used as therapeutic agents and in the fight against infectious diseases. Moreover, the anti-adhesive properties against several pathogens point to the possibility that they might serve as an anti-adhesive coating agent for medical inserts and prevent nosocomial infections, without using synthetic substances. In this study, the antimicrobial, antibiofilm, cell surface hydrophobicity, and antioxidative activities of biosurfactant extracted from Bacillus sp., against four pathogenic strains of Staphylococcus spp. associated with vaginal infection, were studied. Our results have shown that the tested biosurfactant possesses a promising antioxidant potential, and an antibacterial potency against multidrug clinical isolates of Staphylococcus, with an inhibitory diameter ranging between 27 and 37 mm, and a bacterial growth inhibition at an MIC of 1 mg/ mL, obtained. The BioSa3 was highly ef...

Research paper thumbnail of Environmental contaminants and antibiotic resistance as a One Health threat

Research paper thumbnail of Pathogenic Impacts of Bacillus cereus Strains on Crassostrea gigas

Foodborne Pathogens and Disease, 2022

Regarding the economic importance of bivalve farming, a great deal of interest has recently been ... more Regarding the economic importance of bivalve farming, a great deal of interest has recently been devoted to studying the pathogenesis of infectious diseases of these mollusks to prepare for public health emergencies. Bacillus cereus is one of these pathogens; it is a ubiquitous soil bacterium responsible for many types of gastrointestinal diseases associated with food. This study was conducted to determine the pathogenic effect of B. cereus on Crassostrea gigas. This effect was studied by assessing hemocytes death using flow cytometry analysis. The results showed that only ∼15% of C. gigas were able to survive after B. cereus artificial infection with 108 CFU (colony-forming unit)/oyster. Evenly, the percentage of nonviable hemocytes gradually increased with the concentration of B. cereus, with a peak value of ∼40% after infection. Indeed, findings showed that this strain is harmful to C. gigas.

Research paper thumbnail of Control of Staphylococcus aureus methicillin resistant isolated from auricular infections using aqueous and methanolic extracts of Ephedra alata

Saudi Journal of Biological Sciences, 2021

In the current study the potential use of aqueous and methanolic extracts of Ephedra alata aerial... more In the current study the potential use of aqueous and methanolic extracts of Ephedra alata aerial parts as biological control agent against pathogenic bacteria and especially Staphylococcus aureus methicillin resistant isolated from auricular infections was evaluated. Chemical tests and spectrophotometric methods were used for screening and quantification of phytochemicals. The assessment of the antioxidant activity was accomplished by DPPH and ABTS radicals scavenging assays. Extracts were evaluated for their antibacterial efficacy by diffusion and microdilution methods. Biofilm inhibition was tested using XTT assay and the cytotoxicity of extracts was carried out on Vero cell line. The GC-FID analysis revealed that E. alata was rich in unsatured fatty acids. In addition, the aqueous extract had the highest flavonoid and protein contents (30.82 mg QE /g dry extract and 98.92 mg BSAE/g dry extract respectively). However, the methanolic extract had the highest phenolic, sugars and tannins. The antioxidant activity demonstrated that the aqueous extract exhibited the strong potency (IC50 ranged between 0.001 and 0.002 mg/mL). Both extracts displayed antimicrobial activity on Gram negative and positive strains. They were effective against S. aureus isolated from auricular infections. The tested extracts were able to inhibit biofilm formation with concentration-dependent manner. Moreover, no cytotoxic effect on Vero cells line was demonstrated for the extracts. Overall, our findings highlight the potential use of E. alata extract as a novel source of bioactive molecules with antioxidant, antibacterial and antiobiofilm effects for the control of infectious disease especially those associated to S. aureus methicillin resistant.

Research paper thumbnail of The Wheat Pathogenesis Related Protein (TdPR1.2) Ensures Contrasting Behaviors to <i>E. coli</i> Transformant Cells under Stress Conditions

Advances in Microbiology, 2021

The pathogenesis-related proteins 1 (PR-1) gene family play important roles in the plant metaboli... more The pathogenesis-related proteins 1 (PR-1) gene family play important roles in the plant metabolism in response to biotic and abiotic stresses. The wheat TdPR1.2 has been previously isolated and characterized. Here we showed by bio-informatic analysis that TdPR1.2 contains six cysteine residues that are conserved between all PR-1 proteins tested. Using ScanProsite tool, we found that TdPR1.2 structure has a CRISP family signature 1 and 2 located at the C-terminal part of the protein. Those two domains are conserved in many identified PR1.2 proteins in plants. Moreover, SignalIP-5.0 analysis revealed that TdPR1.2 contains a putative signal peptide formed by 25 amino acids at the N-terminal extremity. The presence of this signal peptide suggested that the mature proteins will be secreted after the cleavage of the signal sequence. Further, we investigate the role of the TdPR1.2 proteins in the growth of Escherichia coli transformants cells under different abiotic stresses. Our results showed that the full-length form of TdPR1.2 enhanced tolerance of E. coli against salt and osmotic stress but not to KCl. Moreover, TdPR1.2 protein confers bacterial tolerance to heavy metals in solid and liquid mediums. Based on these results, we suggest that the TdPR1.2 protein could play an important role in response to abiotic stress conditions.

Research paper thumbnail of Effect of environmental stress on cell surface and membrane fatty acids of Lactobacillus plantarum

Archives of Microbiology, 2017

Research paper thumbnail of Culture conditions improvement of Crassostrea gigas using a potential probiotic Bacillus sp strain

Microbial Pathogenesis, 2017

It is well demonstrated that some probiotics improve rearing water quality and thereby have benef... more It is well demonstrated that some probiotics improve rearing water quality and thereby have beneficial effects on reared organisms. We conducted this study to determine the effect of Bacillus consortium on Crassostrea gigas reared in contemned seawater with indigo dye priory treated with Bacillus or no treated. This effect was studied by assessing hemocytes death using flow cytometry analysis. We found that the percentage of decolorization of indigo dye in polluted seawater in presence of C. gigas increased from 41% to 90% when using Bacillus consortium. In these conditions, the hemocytes mortality of reared C. gigas decreased from 87% to 56%. We have demonstrated also that seawater contemned with priory treated indigo with Bacillus consortium is less toxic than seawater contemned with the no treated indigo. The percentage of hemocytes death is 81% for the contemned seawater with indigo and 56% for no contemned seawater. This consortium shows a protector effect of C. gigas against Vibrio harveyi contemning reared seawater.

Research paper thumbnail of Glucomannan's protective effect on the virulence of Vibrio splendidus in pacific oyster

Fish & Shellfish Immunology, 2016

We examine the effect of Glucomannan, extracted from Candida utilis yeast, on immune parameters a... more We examine the effect of Glucomannan, extracted from Candida utilis yeast, on immune parameters and resistance to Vibrio splendidusof Crassostreagigas. Our results showed that Glucomannan was a successful anti-adhesive molecule; it exhibited a stronger inhibitory effect on adhesion of Vibrio splendidus in infected Crassostreagigas. Vibrio splendidus viable cells number declined after incubation with Glucomannan. Furthermore, the Glucomannan diet showed higher activity to trigger the immune response against bacteria. Glucomannan applications, in biological control of seafood associated pathogens can be an alternative solution, providing consumer with a product of good quality owing to the use of 40 non-toxic compounds. Based on our results, Glucomannan could be used as a bio-protective culture in oyster's depuration to prevent Vibrio splendidusgrowth.

Research paper thumbnail of Effect of high temperature on viability of Lactobacillus casei and analysis of secreted and GroEL proteins profiles

Journal of Business Research, Apr 30, 2015

The bacterial heat shock response is characterized by the elevated expression of a number of chap... more The bacterial heat shock response is characterized by the elevated expression of a number of chaperone complexes including the GroEL and the rate change of synthesis of certain proteins (total and secreted). In this work, after incubation at 45°C, total and secreted proteins profiles of stressed bacteria were found to be altered when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In addition, the level expression of GroEL was evaluated with Western blot. Our results show a marked increase in both GroEL expression and protein synthesis at 45°C. These modifications were manifested by the appearance and/or disappearance of bands as well as in the level of expression of certain proteins.

Research paper thumbnail of Acid stress suggests different determinants for polystyrene and HeLa cell adhesion in Lactobacillus casei

Journal of Dairy Science, 2015

Adhesion has been regarded as one of the basic features of probiotics. The aim of this study was ... more Adhesion has been regarded as one of the basic features of probiotics. The aim of this study was to investigate the influence of acid stress on the functional properties, such as hydrophobicity, adhesion to HeLa cells, and composition of membrane fatty acids, of Lactobacillus probiotics strains. Two strains of Lactobacillus casei were used. Adhesion on polystyrene, hydrophobicity, epithelial cells adhesion, and fatty acids analysis were evaluated. Our results showed that the membrane properties such as hydrophobicity and fatty acid composition of stressed strains were significantly changed with different pH values. However, we found that acid stress caused a change in the proportions of unsaturated and saturated fatty acid. The ratio of saturated fatty acid to unsaturated fatty acids observed in acid-stressed Lactobacillus casei cells was significantly higher than the ration in control cells. In addition, we observed a significant decrease in the adhesion ability of these strains to HeLa cells and to a polystyrene surface at low pH. The present finding could first add new insight about the acid stress adaptation and, thus, enable new strategies to be developed aimed at improving the industrial performance of this species under acid stress. Second, no relationship was observed between changes in membrane composition and fluidity induced by acid treatment and adhesion to biotic and abiotic surfaces. In fact, the decrease of cell surface hydrophobicity and the adhesion ability to abiotic surface and the increase of the capacity of adhesion to biotic surface demonstrate that adhesive characteristics will have little relevance in probiotic strain-screening procedures.

Research paper thumbnail of Selection of lactic acid bacteria as candidate probiotics and in vivo test on Artemia nauplii

Aquaculture International, 2013

Lactic acid bacteria (LAB) were isolated from rotifer cultures in a marine hatchery to search for... more Lactic acid bacteria (LAB) were isolated from rotifer cultures in a marine hatchery to search for potential probiotics for marine animals. Fifteen strains were first selected among a total of 55, according to antibacterial activity against Vibrio sp. Among eight strains identified as Lactobacillus casei, four were highly adhesive, suggesting some ability for surface colonization. The other strains were identified as Lactobacillus plantarum, Lactobacillus dextrinicus, and Leuconostoc sp. To validate probiotic potential, Artemia were challenged against pathogenic Vibrio alginolyticus, with or without one of six selected LAB strains. The six strains protected Artemia against the pathogen, to some extent on condition that nutrient enrichment was provided. La. casei BR51 and X2 were preferred, as they were efficient even in the absence of nutrient supply. La. casei X2 was finally selected as candidate probiotic, due to the best growth performances of Artemia, with or without the pathogen.

Research paper thumbnail of Identification of a putative kinase interacting domain in the durum wheat catalase 1 (TdCAT1) protein

Research paper thumbnail of GC/MS Profiling, Antibacterial, Anti-Quorum Sensing, and Antibiofilm Properties of Anethum graveolens L. Essential Oil: Molecular Docking Study and In-Silico ADME Profiling

Plants

Anethum graveolens L. has been known as an aromatic, medicinal, and culinary herb since ancient t... more Anethum graveolens L. has been known as an aromatic, medicinal, and culinary herb since ancient times. The main purpose of this study was to determine the chemical composition, antibacterial, antibiofilm, and anti-quorum sensing activities of the essential oil (EO) obtained by hydro-distillation of the aerial parts. Twelve components were identified, representing 92.55% of the analyzed essential oil. Limonene (48.05%), carvone (37.94%), cis-dihydrocarvone (3.5%), and trans-carvone (1.07%) were the main identified constituents. Results showed that the obtained EO was effective against eight bacterial strains at different degrees. Concerning the antibiofilm activity, limonene was more effective against biofilm formation than the essential oil when tested using sub-inhibitory concentrations. The results of anti-swarming activity tested against P. aeruginosa PAO1 revealed that A. graveolens induced more potent inhibitory effects in the swarming behavior of the PAO1 strain when compared ...

Research paper thumbnail of Genome-Wide Identification and Expression Profiling of Pathogenesis-Related Protein 1 (PR-1) Genes in Durum Wheat (Triticum durum Desf.)

Plants

Pathogen-related proteins (PRs) are diversified proteins with a low molecular weight implicated i... more Pathogen-related proteins (PRs) are diversified proteins with a low molecular weight implicated in plant response to biotic and abiotic stress as well in regulating different functions in plant maturation. Interestingly, no systematical study has been conducted in durum wheat (Triticum turgidum subsp. durum). In the present study, 12 PR-1 genes encoding a CAP superfamily domain were identified in the genome of Triticum turgidum subsp. durum, which is an important cereal, using in silico approaches. Additionally, phylogenetic analysis showed that the PR-1 genes were classified into three groups based on their isoelectric point and the conserved motif domain. Moreover, our analysis showed that most of the TdPR-1 proteins presented an N-terminal signal peptide. Expression patterns analysis showed that the PR-1 gene family presented temporal and spatial specificity and was induced by different abiotic stresses. This is the first report describing the genome-scale analysis of the durum w...

Research paper thumbnail of Characterization of palm date varieties (Phoenix dactylifera L.) growing in Saudi Arabia: Phenotypic diversity estimated by fruit and seed traits

Notulae Botanicae Horti Agrobotanici Cluj-Napoca

In order to determine the variation and the degree of diversity among the most well-known Saudi d... more In order to determine the variation and the degree of diversity among the most well-known Saudi date palm (Phoenix dactylifera L.), this study applied various widely detectible fruit and seed features. The properties of the fruit and seeds were described using ten phenotypic traits. Eighteen date palm varieties from six production sites were used in this study (Ḥaʼil, Al-Madina, Al-Hassa, Al-Qassim, Kharaj, Najran). The data was analysed by Pearson r correlation. The principal components analysis (PCA) and UPGMA clustering were used to analyse the data set. According to PCA, the results showed significant variation among the analysed varieties. Our data shows that seed ratio varies among all varieties. The mean seed weight ratio varies between 4 and 13%. Varieties ‘Raziz’, ‘Lubab’ and ‘Wasily’ demonstrate higher seed ratio (over 10%). Whereas, Fankha depicts a 5 and 4% fresh and dry seed ratio. The statistical analysis indicates that the seed ratio in all 18 varieties is comparable ...

Research paper thumbnail of In Vitro Characterization of Limosilactobacillus reuteri Lac Ib01 (OL468126.1) Isolated from Traditional Sheep Dry Sausage and Evaluation of the Activity of Arthrospira platensis or Phycocyanin on Its Growth-Promoting Ability

Fermentation

The positive impact of probiotic strains on human health is more evident than ever. To achieve th... more The positive impact of probiotic strains on human health is more evident than ever. To achieve the beneficial health effects and desirable functional properties of probiotics, sufficient numbers of these microorganisms must reach the intestinal tract with high survival rates. The purpose of this study was to identify and characterize a novel strain of Limosilactobacillus reuteri isolated from traditional sheep dry sausage and evaluate its growth-promoting ability with the addition of Arthrospira platensis or phycocyanin extract. In vitro experimental approaches were conducted to determine the physiological features of the candidate probiotic isolate, including biochemical identification, 16S rRNA gene sequencing, tolerance assays to acid and bile salts, antimicrobial activities, adherence ability, and antiproliferative assays. The effects of A. platensis or phycocyanin (0, 1, 5, and 8 mg/mL) on the growth of probiotic cultures were studied after 0, 24, 48, and 72 h. Our results show...

Research paper thumbnail of Development of Nanotechnology-Based Drug Delivery Systems for Controlling Clinical Multidrug-Resistant Staphylococcus aureus and Escherichia coli Associated with Aerobic Vaginitis

Pharmaceutics

The growing prevalence of resistance to antibiotics potentially makes Escherichia coli and Staphy... more The growing prevalence of resistance to antibiotics potentially makes Escherichia coli and Staphylococcus aureus serious pathogens, necessitating the development of new antimicrobial agents. We extracted crude biosurfactants from a potential probiotic Bacillus spp. to control pathogenic bacteria associated with aerobic vaginal infection. Using nanotechnology formulations, we developed nanoemulsions based on biosurfactants at different concentrations (1% and 3.33%). The results showed that these nanoemulsions were stable, with a weighted index of 0.3, and demonstrated broad-spectrum antibacterial activity against Escherichia coli and Staphylococcus aureus, with MICs ranging between 1.25 and 4 mg/mL. Additionally, the nanoemulsions exhibited interesting antibiofilm effects. All strains became more sensitive to the antibiotics to which they were resistant because of various biosurfactant formulations combined with antibiotics. Lower concentrations of BNE1% and 3.33% were still more eff...

Research paper thumbnail of Biosurfactants as inhibitors of the adhesion of pathogenic bacteria

Emirates Journal of Food and Agriculture

Biosurfactants have gained more attention in the past decade as possible medical resources. They ... more Biosurfactants have gained more attention in the past decade as possible medical resources. They are useful therapeutic agents againstmany infections because of their antibacterial, antifungal, and antiviral properties. Additionally, the anti-adherent activities of thesecompounds counter to a number of pathogens suggest that they could be useful as an anti-adherent coating for medical inserts, helpingto prevent infections in hospitals without the use of chemicals. This study aims to investigate the antiadhesive activities of biosurfactantsextracted from Lactobacillus brevis and Bacillus sp. against seven clinical pathogens. Biosurfactants at different concentrations wereapplied to polystyrene surfaces, and then the attachment of pathogenic strains was evaluated. The adhesion of microbes to n-hexadecanewas also studied. As a result, the bacterial strains with 50 mg/ml of Lactobacillus brevis biosurfactant displayed a 69–73% reduction inadhesion. In contrast to the first biosurfactant...

Research paper thumbnail of Identification and Expression Profiling of Two Saudi Arabia Catalase Genes from Wheat and Barley in Response to Abiotic and Hormonal Stresses

Antioxidants

Catalase is a crucial enzyme in antioxidant defense systems protecting eukaryotes from oxidative ... more Catalase is a crucial enzyme in antioxidant defense systems protecting eukaryotes from oxidative stress. These proteins are present in almost all living organisms and play important roles in controlling plant responses to biotic and abiotic stresses by catalyzing the decomposition of H2O2. Despite their importance, little is known about their expression in the majority of monocotyledonous species. Here, we isolated and characterized two novel catalase genes from Triticum turgidum and Hordeum vulgare, designated as TtCAT1 and HvCAT1, respectively. Phylogenetic analysis revealed that TtCAT1 and HvCAT1 presented 492 aa and shared an important identity with other catalase proteins belonging to subfamily 1. Using bioinformatic analysis, we predicted the 3D structure models of TtCAT1 and HvCAT1. Interestingly, analysis showed that the novel catalases harbor a peroxisomal targeting signal (PTS1) located at their C-terminus portion, as shown for other catalase proteins. In addition, this mo...

Research paper thumbnail of Comparative Study of Antibacterial, Antibiofilm, Antiswarming and Antiquorum Sensing Activities of Origanum vulgare Essential Oil and Terpinene-4-ol against Pathogenic Bacteria

Life

Essential oils from aromatic and medicinal plants have many bioactive compounds known for their i... more Essential oils from aromatic and medicinal plants have many bioactive compounds known for their important biological activities mainly their antibacterial effects. Here we evaluated qualitatively and quantitatively the biofilm formation capability of pathogenic bacterial strains (n = 8). Then, we investigated the antibacterial, antibiofilm, antiquorum-sensing, and antiswarming efficacy of Origanum vulgare essential oil (EO) and terpinene-4-ol. Our results revealed that EO exhibited a more potent inhibitory effect against the tested strains. While the terpinene-4-ol was found to be more effective against developed Staphylococcus aureus biofilm. Regarding the anti quorum-sensing activity, we noticed that O. vulgare displayed better inhibition percentages in violacein production even at a low concentration (MIC/4). Additionally, this EO showed better inhibition of Pseudomonas aeruginosa PAO1 migration in comparison with the terpinene-4-ol. Our findings revealed that using pure O. vulga...

Research paper thumbnail of Control of Multidrug-Resistant Pathogenic Staphylococci Associated with Vaginal Infection Using Biosurfactants Derived from Potential Probiotic Bacillus Strain

Fermentation

Biosurfactants exhibit antioxidant, antibacterial, antifungal, and antiviral activities. They can... more Biosurfactants exhibit antioxidant, antibacterial, antifungal, and antiviral activities. They can be used as therapeutic agents and in the fight against infectious diseases. Moreover, the anti-adhesive properties against several pathogens point to the possibility that they might serve as an anti-adhesive coating agent for medical inserts and prevent nosocomial infections, without using synthetic substances. In this study, the antimicrobial, antibiofilm, cell surface hydrophobicity, and antioxidative activities of biosurfactant extracted from Bacillus sp., against four pathogenic strains of Staphylococcus spp. associated with vaginal infection, were studied. Our results have shown that the tested biosurfactant possesses a promising antioxidant potential, and an antibacterial potency against multidrug clinical isolates of Staphylococcus, with an inhibitory diameter ranging between 27 and 37 mm, and a bacterial growth inhibition at an MIC of 1 mg/ mL, obtained. The BioSa3 was highly ef...

Research paper thumbnail of Environmental contaminants and antibiotic resistance as a One Health threat

Research paper thumbnail of Pathogenic Impacts of Bacillus cereus Strains on Crassostrea gigas

Foodborne Pathogens and Disease, 2022

Regarding the economic importance of bivalve farming, a great deal of interest has recently been ... more Regarding the economic importance of bivalve farming, a great deal of interest has recently been devoted to studying the pathogenesis of infectious diseases of these mollusks to prepare for public health emergencies. Bacillus cereus is one of these pathogens; it is a ubiquitous soil bacterium responsible for many types of gastrointestinal diseases associated with food. This study was conducted to determine the pathogenic effect of B. cereus on Crassostrea gigas. This effect was studied by assessing hemocytes death using flow cytometry analysis. The results showed that only ∼15% of C. gigas were able to survive after B. cereus artificial infection with 108 CFU (colony-forming unit)/oyster. Evenly, the percentage of nonviable hemocytes gradually increased with the concentration of B. cereus, with a peak value of ∼40% after infection. Indeed, findings showed that this strain is harmful to C. gigas.

Research paper thumbnail of Control of Staphylococcus aureus methicillin resistant isolated from auricular infections using aqueous and methanolic extracts of Ephedra alata

Saudi Journal of Biological Sciences, 2021

In the current study the potential use of aqueous and methanolic extracts of Ephedra alata aerial... more In the current study the potential use of aqueous and methanolic extracts of Ephedra alata aerial parts as biological control agent against pathogenic bacteria and especially Staphylococcus aureus methicillin resistant isolated from auricular infections was evaluated. Chemical tests and spectrophotometric methods were used for screening and quantification of phytochemicals. The assessment of the antioxidant activity was accomplished by DPPH and ABTS radicals scavenging assays. Extracts were evaluated for their antibacterial efficacy by diffusion and microdilution methods. Biofilm inhibition was tested using XTT assay and the cytotoxicity of extracts was carried out on Vero cell line. The GC-FID analysis revealed that E. alata was rich in unsatured fatty acids. In addition, the aqueous extract had the highest flavonoid and protein contents (30.82 mg QE /g dry extract and 98.92 mg BSAE/g dry extract respectively). However, the methanolic extract had the highest phenolic, sugars and tannins. The antioxidant activity demonstrated that the aqueous extract exhibited the strong potency (IC50 ranged between 0.001 and 0.002 mg/mL). Both extracts displayed antimicrobial activity on Gram negative and positive strains. They were effective against S. aureus isolated from auricular infections. The tested extracts were able to inhibit biofilm formation with concentration-dependent manner. Moreover, no cytotoxic effect on Vero cells line was demonstrated for the extracts. Overall, our findings highlight the potential use of E. alata extract as a novel source of bioactive molecules with antioxidant, antibacterial and antiobiofilm effects for the control of infectious disease especially those associated to S. aureus methicillin resistant.

Research paper thumbnail of The Wheat Pathogenesis Related Protein (TdPR1.2) Ensures Contrasting Behaviors to <i>E. coli</i> Transformant Cells under Stress Conditions

Advances in Microbiology, 2021

The pathogenesis-related proteins 1 (PR-1) gene family play important roles in the plant metaboli... more The pathogenesis-related proteins 1 (PR-1) gene family play important roles in the plant metabolism in response to biotic and abiotic stresses. The wheat TdPR1.2 has been previously isolated and characterized. Here we showed by bio-informatic analysis that TdPR1.2 contains six cysteine residues that are conserved between all PR-1 proteins tested. Using ScanProsite tool, we found that TdPR1.2 structure has a CRISP family signature 1 and 2 located at the C-terminal part of the protein. Those two domains are conserved in many identified PR1.2 proteins in plants. Moreover, SignalIP-5.0 analysis revealed that TdPR1.2 contains a putative signal peptide formed by 25 amino acids at the N-terminal extremity. The presence of this signal peptide suggested that the mature proteins will be secreted after the cleavage of the signal sequence. Further, we investigate the role of the TdPR1.2 proteins in the growth of Escherichia coli transformants cells under different abiotic stresses. Our results showed that the full-length form of TdPR1.2 enhanced tolerance of E. coli against salt and osmotic stress but not to KCl. Moreover, TdPR1.2 protein confers bacterial tolerance to heavy metals in solid and liquid mediums. Based on these results, we suggest that the TdPR1.2 protein could play an important role in response to abiotic stress conditions.

Research paper thumbnail of Effect of environmental stress on cell surface and membrane fatty acids of Lactobacillus plantarum

Archives of Microbiology, 2017

Research paper thumbnail of Culture conditions improvement of Crassostrea gigas using a potential probiotic Bacillus sp strain

Microbial Pathogenesis, 2017

It is well demonstrated that some probiotics improve rearing water quality and thereby have benef... more It is well demonstrated that some probiotics improve rearing water quality and thereby have beneficial effects on reared organisms. We conducted this study to determine the effect of Bacillus consortium on Crassostrea gigas reared in contemned seawater with indigo dye priory treated with Bacillus or no treated. This effect was studied by assessing hemocytes death using flow cytometry analysis. We found that the percentage of decolorization of indigo dye in polluted seawater in presence of C. gigas increased from 41% to 90% when using Bacillus consortium. In these conditions, the hemocytes mortality of reared C. gigas decreased from 87% to 56%. We have demonstrated also that seawater contemned with priory treated indigo with Bacillus consortium is less toxic than seawater contemned with the no treated indigo. The percentage of hemocytes death is 81% for the contemned seawater with indigo and 56% for no contemned seawater. This consortium shows a protector effect of C. gigas against Vibrio harveyi contemning reared seawater.

Research paper thumbnail of Glucomannan's protective effect on the virulence of Vibrio splendidus in pacific oyster

Fish & Shellfish Immunology, 2016

We examine the effect of Glucomannan, extracted from Candida utilis yeast, on immune parameters a... more We examine the effect of Glucomannan, extracted from Candida utilis yeast, on immune parameters and resistance to Vibrio splendidusof Crassostreagigas. Our results showed that Glucomannan was a successful anti-adhesive molecule; it exhibited a stronger inhibitory effect on adhesion of Vibrio splendidus in infected Crassostreagigas. Vibrio splendidus viable cells number declined after incubation with Glucomannan. Furthermore, the Glucomannan diet showed higher activity to trigger the immune response against bacteria. Glucomannan applications, in biological control of seafood associated pathogens can be an alternative solution, providing consumer with a product of good quality owing to the use of 40 non-toxic compounds. Based on our results, Glucomannan could be used as a bio-protective culture in oyster's depuration to prevent Vibrio splendidusgrowth.

Research paper thumbnail of Effect of high temperature on viability of Lactobacillus casei and analysis of secreted and GroEL proteins profiles

Journal of Business Research, Apr 30, 2015

The bacterial heat shock response is characterized by the elevated expression of a number of chap... more The bacterial heat shock response is characterized by the elevated expression of a number of chaperone complexes including the GroEL and the rate change of synthesis of certain proteins (total and secreted). In this work, after incubation at 45°C, total and secreted proteins profiles of stressed bacteria were found to be altered when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In addition, the level expression of GroEL was evaluated with Western blot. Our results show a marked increase in both GroEL expression and protein synthesis at 45°C. These modifications were manifested by the appearance and/or disappearance of bands as well as in the level of expression of certain proteins.

Research paper thumbnail of Acid stress suggests different determinants for polystyrene and HeLa cell adhesion in Lactobacillus casei

Journal of Dairy Science, 2015

Adhesion has been regarded as one of the basic features of probiotics. The aim of this study was ... more Adhesion has been regarded as one of the basic features of probiotics. The aim of this study was to investigate the influence of acid stress on the functional properties, such as hydrophobicity, adhesion to HeLa cells, and composition of membrane fatty acids, of Lactobacillus probiotics strains. Two strains of Lactobacillus casei were used. Adhesion on polystyrene, hydrophobicity, epithelial cells adhesion, and fatty acids analysis were evaluated. Our results showed that the membrane properties such as hydrophobicity and fatty acid composition of stressed strains were significantly changed with different pH values. However, we found that acid stress caused a change in the proportions of unsaturated and saturated fatty acid. The ratio of saturated fatty acid to unsaturated fatty acids observed in acid-stressed Lactobacillus casei cells was significantly higher than the ration in control cells. In addition, we observed a significant decrease in the adhesion ability of these strains to HeLa cells and to a polystyrene surface at low pH. The present finding could first add new insight about the acid stress adaptation and, thus, enable new strategies to be developed aimed at improving the industrial performance of this species under acid stress. Second, no relationship was observed between changes in membrane composition and fluidity induced by acid treatment and adhesion to biotic and abiotic surfaces. In fact, the decrease of cell surface hydrophobicity and the adhesion ability to abiotic surface and the increase of the capacity of adhesion to biotic surface demonstrate that adhesive characteristics will have little relevance in probiotic strain-screening procedures.

Research paper thumbnail of Selection of lactic acid bacteria as candidate probiotics and in vivo test on Artemia nauplii

Aquaculture International, 2013

Lactic acid bacteria (LAB) were isolated from rotifer cultures in a marine hatchery to search for... more Lactic acid bacteria (LAB) were isolated from rotifer cultures in a marine hatchery to search for potential probiotics for marine animals. Fifteen strains were first selected among a total of 55, according to antibacterial activity against Vibrio sp. Among eight strains identified as Lactobacillus casei, four were highly adhesive, suggesting some ability for surface colonization. The other strains were identified as Lactobacillus plantarum, Lactobacillus dextrinicus, and Leuconostoc sp. To validate probiotic potential, Artemia were challenged against pathogenic Vibrio alginolyticus, with or without one of six selected LAB strains. The six strains protected Artemia against the pathogen, to some extent on condition that nutrient enrichment was provided. La. casei BR51 and X2 were preferred, as they were efficient even in the absence of nutrient supply. La. casei X2 was finally selected as candidate probiotic, due to the best growth performances of Artemia, with or without the pathogen.