The NATURE-HF registry was aimed to describe clinical epidemiology and 1-year outcomes of outpati... more The NATURE-HF registry was aimed to describe clinical epidemiology and 1-year outcomes of outpatients and inpatients with heart failure (HF). This is a prospective, multicenter, observational survey conducted in Tunisian Cardiology centers. A total of 2040 patients were included in the study. Of these, 1632 (80%) were outpatients with chronic HF (CHF). The mean hospital stay was 8.7 ± 8.2 days. The mortality rate during the initial hospitalization event for AHF was 7.4%. The all-cause 1-year mortality rate was 22.8% among AHF patients and 10.6% among CHF patients. Among CHF patients, the older age, diabetes, anemia, reduced EF, ischemic etiology, residual congestion and the absence of ACEI/ ARBs treatment were independent predictors of 1-year cumulative rates of rehospitalization and mortality. The female sex and the functional status were independent predictors of 1-year all-cause mortality and rehospitalization in AHF patients. This study confirmed that acute HF is still associate...
Stone surfaces are extreme environments that support microbial life. This microbial growth occurs... more Stone surfaces are extreme environments that support microbial life. This microbial growth occurs despite unfavourable conditions associated with stone including limited sources of nutrients and water, high pH and exposure to extreme variations in temperature, humidity and irradiation. These stone-dwelling microbes are often resistant to extreme environments including exposure to desiccation, heavy metals, UV and Gamma irradiation. Here, we report on the effects of climate and stone geochemistry on microbiomes of Roman stone ruins in North Africa. Stone microbiomes were dominated by Actinobacteria, Cyanobacteria and Proteobacteria but were heavily impacted by climate variables that influenced water availability. Stone geochemistry also influenced community diversity, particularly through biologically available P, Mn and Zn. Functions associated with photosynthesis and UV protection were enriched in the metagenomes, indicating the significance of these functions for community survival on stones. Core members of the stone microbial communities were also identified and included Geodermatophilaceae, Rubrobacter, Sphingomonas and others. Our research has helped to expand the understanding of stone microbial community structure and functional capacity within the context of varying climates, geochemical properties and stone conditions.
Background The frequency of heart failure (HF) in Tunisia is on the rise and has now become a pub... more Background The frequency of heart failure (HF) in Tunisia is on the rise and has now become a public health concern. This is mainly due to an aging Tunisian population (Tunisia has one of the oldest populations in Africa as well as the highest life expectancy in the continent) and an increase in coronary artery disease and hypertension. However, no extensive data are available on demographic characteristics, prognosis, and quality of care of patients with HF in Tunisia (nor in North Africa). Objective The aim of this study was to analyze, follow, and evaluate patients with HF in a large nation-wide multicenter trial. Methods A total of 1700 patients with HF diagnosed by the investigator will be included in the National Tunisian Registry of Heart Failure study (NATURE-HF). Patients must visit the cardiology clinic 1, 3, and 12 months after study inclusion. This follow-up is provided by the investigator. All data are collected via the DACIMA Clinical Suite web interface. Results At th...
Actinorhizal plants form a symbiotic association with the nitrogen-fixing actinobacteria Frankia.... more Actinorhizal plants form a symbiotic association with the nitrogen-fixing actinobacteria Frankia. These plants have important economic and ecological benefits including land reclamation, soil stabilization, and reforestation. Recently, many non-Frankia actinobacteria have been isolated from actinorhizal root nodules suggesting that they might contribute to nodulation. Two Nocardia strains, BMG51109 and BMG111209, were isolated from Casuarina glauca nodules, and they induced root nodule-like structures in original host plant promoting seedling growth. The formed root nodule-like structures lacked a nodular root at the apex, were not capable of reducing nitrogen and had their cortical cells occupied with rod-shaped Nocardiae cells. Both Nocardia strains induced root hair deformation on the host plant. BMG111209 strain induced the expression of the ProCgNin:Gus gene, a plant gene involved in the early steps of the infection process and nodulation development. Nocardia strain BMG51109 produced three types of auxins (Indole-3-acetic acid [IAA], Indole-3-Byturic Acid [IBA] and Phenyl Acetic Acid [PAA]), while Nocardia BMG111209 only produced IAA. Analysis of the Nocardia genomes identified several important predicted biosynthetic gene clusters for plant phytohormones, secondary metabolites, and novel natural products. Co-infection studies showed that Nocardia strain BMG51109 plays a role as a "helper bacteria" promoting an earlier onset of nodulation. This study raises many questions on the ecological significance and functionality of Nocardia bacteria in actinorhizal symbioses.
International journal of systematic and evolutionary microbiology, 2018
A novel, non-motile, coccoid, Gram-stain-positive actinobacterium, designated BMG 862, was isolat... more A novel, non-motile, coccoid, Gram-stain-positive actinobacterium, designated BMG 862, was isolated from a marble sample collected from the Bulla Regia monument, Northern Tunisia. Its taxonomic position was determined using a polyphasic approach. Results from chemotaxonomic analyses showed MK-9(H4), MK-8(H4) and MK-9(H2) as the predominant menaquinones. The major polar lipids comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, hydroxy-phosphatidylethanolamine and three unidentified phospholipids. The fatty acids consisted of significant amounts (≥10 %) of iso-C16 : 0, C17 : 1ω8c, iso-C15 : 0 and C16 : 1ω7c. Phylogenetic analysis on the basis of 16S rRNA gene sequence comparisons showed that strain BMG 862 belongs to the genus Blastococcus, being most closely related to Blastococcus saxobsidens (=DSM 44509) (99.5 %) and Blastococcus capsensis (=DSM 46835=CECT 8876) (99.3 %). The genomic DNA G+C content of t...
Here, we present draft genome sequences for three atypical Frankia strains (lineage 4) that were ... more Here, we present draft genome sequences for three atypical Frankia strains (lineage 4) that were isolated from root nodules but are unable to reinfect actinorhizal plants. The genome sizes of Frankia sp. strains EUN1h, BMG5.36, and NRRL B16386 were 9.91, 11.20, and 9.43 Mbp, respectively.
The taxonomic position of an actinobacterial isolate, designated strain BMG 822, isolated from li... more The taxonomic position of an actinobacterial isolate, designated strain BMG 822, isolated from limestone from the Amphitheater of El Jem (Coliseum Thysdrus), Tunisia, was established using a polyphasic approach. Strain BMG 822 was found to grow well at 30 °C and pH 6.5-8.0, and to be coral-coloured, Gram-positive, catalase and oxidase negative. Whole cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid, glucose, galactose and ribose. The phospholipids detected were diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, an unidentified glycophospholipid and six unidentified phospholipids. MK-9(H) was found to be the predominant menaquinone, followed by MK-9(H) and MK-9. The major cellular fatty acids were identified as iso-C, C ω9c, C ω8c and iso-H-C. The G+C content of the DNA (73.2%) is typical of the genus. High degrees of 16S rRNA gene sequence similarity were found with the type strains of the genus Blastococcus (97.1-98.3%) followed by the type strains of Modestobacter (96.8-97.8%). Based on the above data and the phenotypic differences from the type strains of Blastococcus species, it is proposed that the isolate BMG 822 (=DSM 46837=CECT 8823) should be classified as the type strain of a novel species, Blastococcus colisei sp. nov.
International journal of systematic and evolutionary microbiology, Jan 23, 2016
A novel Gram-reaction-positive actinobacterium designated BMG 804T was isolated from an archaeolo... more A novel Gram-reaction-positive actinobacterium designated BMG 804T was isolated from an archaeological Roman pool located in Gafsa, Tunisia. The strain grew as dry bright orange colonies at 30°C and pH 6.0-8.0. It contained meso-diaminopimelic acid in the cell wall. The whole-cell sugars consisted of glucose, rhamnose and ribose. Polar lipids present were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, an unidentified glycolipid and two unidentified phospholipids. MK-9(H4) was the predominant menaquinone. The fatty acid profile contained major amounts (>5%) of C17:18c, C16:17c, iso-C15:0, iso-C16:0 and iso-C16:1 H. The 16S rRNA gene sequence of BMG 804T showed 99.4 % as highest sequence similarity with Blastococcus saxobsidens. DNA-DNA hybridization between strain BMG 804T and B. saxobsidens DSM 44509T was 48.6 ± 6.6 %. The G+C content of the DNA was 73.7 mol%. On the basis of the phenotypic and genotypic characteristics, including DNA...
Here, we report the first genome sequence of a Nocardia plant endophyte, N. casuarinae strain BMG... more Here, we report the first genome sequence of a Nocardia plant endophyte, N. casuarinae strain BMG51109, isolated from Casuarina glauca root nodules. The improved high-quality draft genome sequence contains 8,787,999 bp with a 68.90% GC content and 7,307 predicted protein-coding genes.
Nocardia sp. strain BMG111209 is a non-Frankia actinobacterium isolated from root nodules of Casu... more Nocardia sp. strain BMG111209 is a non-Frankia actinobacterium isolated from root nodules of Casuarina glauca in Tunisia. Here, we report the 9.1-Mbp draft genome sequence of Nocardia sp. strain BMG111209 with a G + C content of 69.19% and 8,122 candidate protein-encoding genes.
The Geodermatophilaceae are unique model systems to study the ability to thrive on or within ston... more The Geodermatophilaceae are unique model systems to study the ability to thrive on or within stones and their proteogenomes (referring to the whole protein arsenal encoded by the genome) could provide important insight into their adaptation mechanisms. Here we report the detailed comparative genome analysis of Blastococcus saxobsidens (Bs), Modestobacter marinus (Mm) and Geodermatophilus obscurus (Go) isolated respectively from the interior and the surface of calcarenite stones and from desert sandy soils. The genome-scale analysis of Bs, Mm and Go illustrates how adaptation to these niches can be achieved through various strategies including 'molecular tinkering/opportunism' as shown by the high proportion of lost, duplicated or horizontally transferred genes and ORFans. Using high-throughput discovery proteomics, the three proteomes under unstressed conditions were analyzed, highlighting the most abundant biomarkers and the main protein factors. Proteomic data corroborated previously demonstrated stone-related ecological distribution. For instance, these data showed starvation-inducible, biofilm-related and DNA-protection proteins as signatures of the microbes associated with the interior, surface and outside of stones, respectively.The ISME Journal advance online publication, 30 June 2015; doi:10.1038/ismej.2015.108.
International Journal of Systematic and Evolutionary Microbiology, 2015
A novel gamma-radiation-resistant and Gram positive actinobacterium designated BMG8133T was isola... more A novel gamma-radiation-resistant and Gram positive actinobacterium designated BMG8133T was isolated from a limestone collected in the Sahara desert of Tunisia. The strain produced dry pale pink colonies with an optimum growth at 35-40°C and pH 6.5-8.0. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Geodermatophilus. The peptidoglycan contained meso-diaminopimelic acid as diagnostic diaminoacid. The main polar lipids were phosphatidylcholine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine and one unspecified glycolipid. MK-9(H4) was the dominant menaquinone. Galactose and glucose was detected as diagnostic sugar. The major cellular fatty acids were branched-chain saturated acids iso-C16:0 and iso-C15:0. The DNA G+C content of the new strain is 74.5 %. The 16S rRNA gene sequence showed 98.3 % as highest sequence identity with Geodermatophilus ruber species. Based on phenotypic results and 16S rRNA gene sequence analysis, strain BMG8133T is proposed to represent a novel species, Geodermatophilus sabuli. Type strain is BMG8133T (=DSM 46844T = CECT 8820T).
ABSTRACT This work aims to evaluate the antibacterial activity of lyophilized aqueous extract of ... more ABSTRACT This work aims to evaluate the antibacterial activity of lyophilized aqueous extract of Coriaria myrtifolia against twenty three bacterial strains belonging to twelve main genera, known to be involved in some pathologies and / or in the food spoilage process: Bacillus sp., E. coli, E. hafnia, Enterococcus sp., Klebsiella sp,. Listeria monocytogenes, Pseudomonas sp., Salmonella sp., Serratia sp., Shigella sp., S. aureus and Streptomyces sp. To achieve this goal, the disk diffusion method was used. The study revealed that C. myrtifolia’s aqueous extract is active against most of the tested strains and that activity is proportional to its concentration. The intensity of inhibition depends on the extract’s concentration on one hand and on the bacterial species tested on the other hand. Indexing terms/Keywords: Coriaria myrtifolia, Aqueous extracts, Antibacterial activity.
An orange-black, Gram-positive, aerobic and gamma-ray resistant actinobacterium was isolated from... more An orange-black, Gram-positive, aerobic and gamma-ray resistant actinobacterium was isolated from the ruins of a Roman aqueduct located in Northern Tunisia. The optimal growth for the strain was found to be at 25-35 °C and at pH 6.0-9.5. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Geodermatophilus. The peptidoglycan was found to contain meso-diaminopimelic acid as diagnostic diaminoacid. The main polar lipids were identified as phosphatidylcholine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, an unidentified glycolipid and an unidentified aminophospholipid; MK-9(H4) was found to be the dominant menaquinone and galactose was detected as the diagnostic sugar, with glucose, ribose and mannose also present. The major cellular fatty acids were identified as branched-chain saturated acids iso-C16:0, iso-C15:0 and iso-H-C16:0. The 16S rRNA gene showed 95.4-99.6 % sequence identity with the type stra...
The taxonomic position of an aerobic actinobacterial strain, BMG841(T), isolated from the Bulla R... more The taxonomic position of an aerobic actinobacterial strain, BMG841(T), isolated from the Bulla Regia monument (Tunisia) and exhibiting a high resistance to gamma-radiation (D10 ~9 kGy) was determined using polyphasic approach. The optimal growth range was found to be 25-35 °C at pH of 7.0-8.5. The strain was observed to form black dry colonies. Chemotaxonomic characteristics of the isolate showed a cell wall type III, with galactose and glucose as diagnostic sugars; phosphatidylcholine, phosphatidylinositol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid as main polar lipids; and MK-9(H4) as the predominant menaquinone. The major cellular fatty acids were identified as iso-C16:0 and iso-C15:0. Phylogenetic analysis indicated that strain BMG841(T) represents a novel member of the genus Geodermatophilus with high 16S rRNA gene sequence identity with Geodermatophilus saharensis (98.28 %). Based on phylogenetic and phenotypic analysis, strain BMG841(T) ...
The NATURE-HF registry was aimed to describe clinical epidemiology and 1-year outcomes of outpati... more The NATURE-HF registry was aimed to describe clinical epidemiology and 1-year outcomes of outpatients and inpatients with heart failure (HF). This is a prospective, multicenter, observational survey conducted in Tunisian Cardiology centers. A total of 2040 patients were included in the study. Of these, 1632 (80%) were outpatients with chronic HF (CHF). The mean hospital stay was 8.7 ± 8.2 days. The mortality rate during the initial hospitalization event for AHF was 7.4%. The all-cause 1-year mortality rate was 22.8% among AHF patients and 10.6% among CHF patients. Among CHF patients, the older age, diabetes, anemia, reduced EF, ischemic etiology, residual congestion and the absence of ACEI/ ARBs treatment were independent predictors of 1-year cumulative rates of rehospitalization and mortality. The female sex and the functional status were independent predictors of 1-year all-cause mortality and rehospitalization in AHF patients. This study confirmed that acute HF is still associate...
Stone surfaces are extreme environments that support microbial life. This microbial growth occurs... more Stone surfaces are extreme environments that support microbial life. This microbial growth occurs despite unfavourable conditions associated with stone including limited sources of nutrients and water, high pH and exposure to extreme variations in temperature, humidity and irradiation. These stone-dwelling microbes are often resistant to extreme environments including exposure to desiccation, heavy metals, UV and Gamma irradiation. Here, we report on the effects of climate and stone geochemistry on microbiomes of Roman stone ruins in North Africa. Stone microbiomes were dominated by Actinobacteria, Cyanobacteria and Proteobacteria but were heavily impacted by climate variables that influenced water availability. Stone geochemistry also influenced community diversity, particularly through biologically available P, Mn and Zn. Functions associated with photosynthesis and UV protection were enriched in the metagenomes, indicating the significance of these functions for community survival on stones. Core members of the stone microbial communities were also identified and included Geodermatophilaceae, Rubrobacter, Sphingomonas and others. Our research has helped to expand the understanding of stone microbial community structure and functional capacity within the context of varying climates, geochemical properties and stone conditions.
Background The frequency of heart failure (HF) in Tunisia is on the rise and has now become a pub... more Background The frequency of heart failure (HF) in Tunisia is on the rise and has now become a public health concern. This is mainly due to an aging Tunisian population (Tunisia has one of the oldest populations in Africa as well as the highest life expectancy in the continent) and an increase in coronary artery disease and hypertension. However, no extensive data are available on demographic characteristics, prognosis, and quality of care of patients with HF in Tunisia (nor in North Africa). Objective The aim of this study was to analyze, follow, and evaluate patients with HF in a large nation-wide multicenter trial. Methods A total of 1700 patients with HF diagnosed by the investigator will be included in the National Tunisian Registry of Heart Failure study (NATURE-HF). Patients must visit the cardiology clinic 1, 3, and 12 months after study inclusion. This follow-up is provided by the investigator. All data are collected via the DACIMA Clinical Suite web interface. Results At th...
Actinorhizal plants form a symbiotic association with the nitrogen-fixing actinobacteria Frankia.... more Actinorhizal plants form a symbiotic association with the nitrogen-fixing actinobacteria Frankia. These plants have important economic and ecological benefits including land reclamation, soil stabilization, and reforestation. Recently, many non-Frankia actinobacteria have been isolated from actinorhizal root nodules suggesting that they might contribute to nodulation. Two Nocardia strains, BMG51109 and BMG111209, were isolated from Casuarina glauca nodules, and they induced root nodule-like structures in original host plant promoting seedling growth. The formed root nodule-like structures lacked a nodular root at the apex, were not capable of reducing nitrogen and had their cortical cells occupied with rod-shaped Nocardiae cells. Both Nocardia strains induced root hair deformation on the host plant. BMG111209 strain induced the expression of the ProCgNin:Gus gene, a plant gene involved in the early steps of the infection process and nodulation development. Nocardia strain BMG51109 produced three types of auxins (Indole-3-acetic acid [IAA], Indole-3-Byturic Acid [IBA] and Phenyl Acetic Acid [PAA]), while Nocardia BMG111209 only produced IAA. Analysis of the Nocardia genomes identified several important predicted biosynthetic gene clusters for plant phytohormones, secondary metabolites, and novel natural products. Co-infection studies showed that Nocardia strain BMG51109 plays a role as a "helper bacteria" promoting an earlier onset of nodulation. This study raises many questions on the ecological significance and functionality of Nocardia bacteria in actinorhizal symbioses.
International journal of systematic and evolutionary microbiology, 2018
A novel, non-motile, coccoid, Gram-stain-positive actinobacterium, designated BMG 862, was isolat... more A novel, non-motile, coccoid, Gram-stain-positive actinobacterium, designated BMG 862, was isolated from a marble sample collected from the Bulla Regia monument, Northern Tunisia. Its taxonomic position was determined using a polyphasic approach. Results from chemotaxonomic analyses showed MK-9(H4), MK-8(H4) and MK-9(H2) as the predominant menaquinones. The major polar lipids comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, hydroxy-phosphatidylethanolamine and three unidentified phospholipids. The fatty acids consisted of significant amounts (≥10 %) of iso-C16 : 0, C17 : 1ω8c, iso-C15 : 0 and C16 : 1ω7c. Phylogenetic analysis on the basis of 16S rRNA gene sequence comparisons showed that strain BMG 862 belongs to the genus Blastococcus, being most closely related to Blastococcus saxobsidens (=DSM 44509) (99.5 %) and Blastococcus capsensis (=DSM 46835=CECT 8876) (99.3 %). The genomic DNA G+C content of t...
Here, we present draft genome sequences for three atypical Frankia strains (lineage 4) that were ... more Here, we present draft genome sequences for three atypical Frankia strains (lineage 4) that were isolated from root nodules but are unable to reinfect actinorhizal plants. The genome sizes of Frankia sp. strains EUN1h, BMG5.36, and NRRL B16386 were 9.91, 11.20, and 9.43 Mbp, respectively.
The taxonomic position of an actinobacterial isolate, designated strain BMG 822, isolated from li... more The taxonomic position of an actinobacterial isolate, designated strain BMG 822, isolated from limestone from the Amphitheater of El Jem (Coliseum Thysdrus), Tunisia, was established using a polyphasic approach. Strain BMG 822 was found to grow well at 30 °C and pH 6.5-8.0, and to be coral-coloured, Gram-positive, catalase and oxidase negative. Whole cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid, glucose, galactose and ribose. The phospholipids detected were diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, an unidentified glycophospholipid and six unidentified phospholipids. MK-9(H) was found to be the predominant menaquinone, followed by MK-9(H) and MK-9. The major cellular fatty acids were identified as iso-C, C ω9c, C ω8c and iso-H-C. The G+C content of the DNA (73.2%) is typical of the genus. High degrees of 16S rRNA gene sequence similarity were found with the type strains of the genus Blastococcus (97.1-98.3%) followed by the type strains of Modestobacter (96.8-97.8%). Based on the above data and the phenotypic differences from the type strains of Blastococcus species, it is proposed that the isolate BMG 822 (=DSM 46837=CECT 8823) should be classified as the type strain of a novel species, Blastococcus colisei sp. nov.
International journal of systematic and evolutionary microbiology, Jan 23, 2016
A novel Gram-reaction-positive actinobacterium designated BMG 804T was isolated from an archaeolo... more A novel Gram-reaction-positive actinobacterium designated BMG 804T was isolated from an archaeological Roman pool located in Gafsa, Tunisia. The strain grew as dry bright orange colonies at 30°C and pH 6.0-8.0. It contained meso-diaminopimelic acid in the cell wall. The whole-cell sugars consisted of glucose, rhamnose and ribose. Polar lipids present were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, an unidentified glycolipid and two unidentified phospholipids. MK-9(H4) was the predominant menaquinone. The fatty acid profile contained major amounts (>5%) of C17:18c, C16:17c, iso-C15:0, iso-C16:0 and iso-C16:1 H. The 16S rRNA gene sequence of BMG 804T showed 99.4 % as highest sequence similarity with Blastococcus saxobsidens. DNA-DNA hybridization between strain BMG 804T and B. saxobsidens DSM 44509T was 48.6 ± 6.6 %. The G+C content of the DNA was 73.7 mol%. On the basis of the phenotypic and genotypic characteristics, including DNA...
Here, we report the first genome sequence of a Nocardia plant endophyte, N. casuarinae strain BMG... more Here, we report the first genome sequence of a Nocardia plant endophyte, N. casuarinae strain BMG51109, isolated from Casuarina glauca root nodules. The improved high-quality draft genome sequence contains 8,787,999 bp with a 68.90% GC content and 7,307 predicted protein-coding genes.
Nocardia sp. strain BMG111209 is a non-Frankia actinobacterium isolated from root nodules of Casu... more Nocardia sp. strain BMG111209 is a non-Frankia actinobacterium isolated from root nodules of Casuarina glauca in Tunisia. Here, we report the 9.1-Mbp draft genome sequence of Nocardia sp. strain BMG111209 with a G + C content of 69.19% and 8,122 candidate protein-encoding genes.
The Geodermatophilaceae are unique model systems to study the ability to thrive on or within ston... more The Geodermatophilaceae are unique model systems to study the ability to thrive on or within stones and their proteogenomes (referring to the whole protein arsenal encoded by the genome) could provide important insight into their adaptation mechanisms. Here we report the detailed comparative genome analysis of Blastococcus saxobsidens (Bs), Modestobacter marinus (Mm) and Geodermatophilus obscurus (Go) isolated respectively from the interior and the surface of calcarenite stones and from desert sandy soils. The genome-scale analysis of Bs, Mm and Go illustrates how adaptation to these niches can be achieved through various strategies including 'molecular tinkering/opportunism' as shown by the high proportion of lost, duplicated or horizontally transferred genes and ORFans. Using high-throughput discovery proteomics, the three proteomes under unstressed conditions were analyzed, highlighting the most abundant biomarkers and the main protein factors. Proteomic data corroborated previously demonstrated stone-related ecological distribution. For instance, these data showed starvation-inducible, biofilm-related and DNA-protection proteins as signatures of the microbes associated with the interior, surface and outside of stones, respectively.The ISME Journal advance online publication, 30 June 2015; doi:10.1038/ismej.2015.108.
International Journal of Systematic and Evolutionary Microbiology, 2015
A novel gamma-radiation-resistant and Gram positive actinobacterium designated BMG8133T was isola... more A novel gamma-radiation-resistant and Gram positive actinobacterium designated BMG8133T was isolated from a limestone collected in the Sahara desert of Tunisia. The strain produced dry pale pink colonies with an optimum growth at 35-40°C and pH 6.5-8.0. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Geodermatophilus. The peptidoglycan contained meso-diaminopimelic acid as diagnostic diaminoacid. The main polar lipids were phosphatidylcholine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine and one unspecified glycolipid. MK-9(H4) was the dominant menaquinone. Galactose and glucose was detected as diagnostic sugar. The major cellular fatty acids were branched-chain saturated acids iso-C16:0 and iso-C15:0. The DNA G+C content of the new strain is 74.5 %. The 16S rRNA gene sequence showed 98.3 % as highest sequence identity with Geodermatophilus ruber species. Based on phenotypic results and 16S rRNA gene sequence analysis, strain BMG8133T is proposed to represent a novel species, Geodermatophilus sabuli. Type strain is BMG8133T (=DSM 46844T = CECT 8820T).
ABSTRACT This work aims to evaluate the antibacterial activity of lyophilized aqueous extract of ... more ABSTRACT This work aims to evaluate the antibacterial activity of lyophilized aqueous extract of Coriaria myrtifolia against twenty three bacterial strains belonging to twelve main genera, known to be involved in some pathologies and / or in the food spoilage process: Bacillus sp., E. coli, E. hafnia, Enterococcus sp., Klebsiella sp,. Listeria monocytogenes, Pseudomonas sp., Salmonella sp., Serratia sp., Shigella sp., S. aureus and Streptomyces sp. To achieve this goal, the disk diffusion method was used. The study revealed that C. myrtifolia’s aqueous extract is active against most of the tested strains and that activity is proportional to its concentration. The intensity of inhibition depends on the extract’s concentration on one hand and on the bacterial species tested on the other hand. Indexing terms/Keywords: Coriaria myrtifolia, Aqueous extracts, Antibacterial activity.
An orange-black, Gram-positive, aerobic and gamma-ray resistant actinobacterium was isolated from... more An orange-black, Gram-positive, aerobic and gamma-ray resistant actinobacterium was isolated from the ruins of a Roman aqueduct located in Northern Tunisia. The optimal growth for the strain was found to be at 25-35 °C and at pH 6.0-9.5. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Geodermatophilus. The peptidoglycan was found to contain meso-diaminopimelic acid as diagnostic diaminoacid. The main polar lipids were identified as phosphatidylcholine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, an unidentified glycolipid and an unidentified aminophospholipid; MK-9(H4) was found to be the dominant menaquinone and galactose was detected as the diagnostic sugar, with glucose, ribose and mannose also present. The major cellular fatty acids were identified as branched-chain saturated acids iso-C16:0, iso-C15:0 and iso-H-C16:0. The 16S rRNA gene showed 95.4-99.6 % sequence identity with the type stra...
The taxonomic position of an aerobic actinobacterial strain, BMG841(T), isolated from the Bulla R... more The taxonomic position of an aerobic actinobacterial strain, BMG841(T), isolated from the Bulla Regia monument (Tunisia) and exhibiting a high resistance to gamma-radiation (D10 ~9 kGy) was determined using polyphasic approach. The optimal growth range was found to be 25-35 °C at pH of 7.0-8.5. The strain was observed to form black dry colonies. Chemotaxonomic characteristics of the isolate showed a cell wall type III, with galactose and glucose as diagnostic sugars; phosphatidylcholine, phosphatidylinositol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid as main polar lipids; and MK-9(H4) as the predominant menaquinone. The major cellular fatty acids were identified as iso-C16:0 and iso-C15:0. Phylogenetic analysis indicated that strain BMG841(T) represents a novel member of the genus Geodermatophilus with high 16S rRNA gene sequence identity with Geodermatophilus saharensis (98.28 %). Based on phylogenetic and phenotypic analysis, strain BMG841(T) ...
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Papers by Karima Hezbri