Tapping into haloalkaliphilic bacteria for sustainable agriculture in treated wastewater: insights into genomic fitness and environmental adaptation.

The increasing salinity and alkalinity of soils pose a global challenge, particularly in arid regions such as Tunisia, where about 50% of lands are sensitive to soil salinization. Anthropogenic activities, including the use of treated wastewater (TWW) for irrigation, exacerbate these issues. Haloalkaliphilic bacteria, adapted to TWW conditions and exhibiting plant-growth promotion (PGP) and biocontrol traits, could offer solutions. In this study, 24 haloalkaliphilic bacterial strains were isolated from rhizosphere sample of olive tree irrigated with TWW for more than 20 years. The bacterial identification using 16S rRNA gene sequencing showed that the haloalkaliphilic isolates, capable of thriving in high salinity and alkaline pH, were primarily affiliated to Bacillota (Oceanobacillus and Staphylococcus). Notably, these strains exhibited biofertilization and enzyme production under both normal and saline conditions. Traits such as phosphate solubilization, and the production of exopolysaccharide, siderophore, ammonia, and hydrogen cyanide were observed. The strains also demonstrated enzymatic activities, including protease, amylase, and esterase. Four selected haloalkaliphilic PGPR strains displayed antifungal activity against Alternaria terricola, with three showing tolerances to heavy metals and pesticides. The strain Oceanobacillus picturea M4W.A2 was selected for genome sequencing. Phylogenomic analyses indicated that the extreme environmental conditions probably influenced the development of specific adaptations in M4W.A2 strain, differentiating it from other Oceanobacillus picturae strains. The presence of the key genes associated with plant growth promotion, osmotic and oxidative stress tolerance, antibiotic and heavy metals resistance hinted the functional capabilities might help the strain M4W.A2 to thrive in TWW-irrigated soils. By demonstrating this connection, we aim to improve our understanding of genomic fitness to stressed environments. Moreover, the identification of gene duplication and horizontal gene transfer events through mobile genetic elements allow the comprehension of these adaptation dynamics. This study reveals that haloalkaliphilc bacteria from TWW-irrigated rhizosphere exhibit plant-growth promotion and biocontrol traits, with genomic adaptations enabling their survival in high salinity and alkaline conditions, offering potential solutions for soil salinization issues.

The promise of probiotics in honeybee health and disease management.

Over the last decades, losses of bee populations have been observed worldwide. A panoply of biotic and abiotic factors, as well as the interplay among them, has been suggested to be responsible for bee declines, but definitive causes have not yet been identified. Among pollinators, the honeybee Apis mellifera is threatened by various diseases and environmental stresses, which have been shown to impact the insect gut microbiota that is known to be fundamental for host metabolism, development and immunity. Aimed at preserving the gut homeostasis, many researches are currently focusing on improving the honeybee health through the administration of probiotics e.g., by boosting the innate immune response against microbial infections. Here, we review the knowledge available on the characterization of the microbial diversity associated to honeybees and the use of probiotic symbionts as a promising approach to maintain honeybee fitness, sustaining a healthy gut microbiota and enhancing its crucial relationship with the host immune system.

A comparative GC-MS analysis of bioactive secondary metabolites produced by halotolerant Bacillus spp. isolated from the Great Sebkha of Oran.

The reemergence of infectious diseases and resistant pathogens represents a serious problem for human life. Hence, the screening for new or alternative antimicrobial compounds is still urgent. Unusual ecosystems such as saline habitats are considered promising environments for the purposes of isolating bacterial strains able to produce potent natural products. The aim of this study is the identification of bioactive compounds biosynthesized by three halotolerant strains isolated from the Sebkha of Oran (Algeria) using gas chromatography coupled to mass spectrometry. Primary screening investigation of antimicrobial activities were performed against reference bacterial and fungal strains and revealed a broad-spectrum activity. Secondary metabolite extraction was carried out using ethyl acetate and chloroform. Crude extracts were tested for bioactivity using the disc diffusion method and subjected to GC-MS analysis. The extracts showed an important inhibitory effect against all tested strains. Fifty-six compounds were identified; they include tert-butyl phenol compounds, fatty acid methyl esters due to the methylation procedure, hydrocarbons, aldehydes, benzoquinones, pyrrols, and terpenes. Literature reports such compounds to have wide biological and pharmaceutical applications. The molecular identification of the three isolates was achieved using the 16S-23S rRNA gene intergenic spacer region (ITS) and 16S rRNA sequencing. Partial 16S rRNA gene sequencing showed very high similarity with many species of Bacillus. This study provided insights on the potential of halotolerant Bacillus as drug research target for bioactive metabolites. The findings suggest that the Great Sebkha of Oran is a valuable source of strains exhibiting variety of beneficial attributes that can be utilized in the development of biological antibiotics.

Genome analysis provides insights into crude oil degradation and biosurfactant production by extremely halotolerant Halomonas desertis G11 isolated from Chott El-Djerid salt-lake in Tunisian desert.

Here, we report the genomic features and the bioremediation potential of Halomonas desertis G11, a new halophilic species which uses crude oil as a carbon and energy source and displays intrinsic resistance to salt stress conditions (optimum growth at 10% NaCl). G11 genome (3.96 Mb) had a mean GC content of 57.82%, 3622 coding sequences, 480 subsystems and 64 RNA genes. Annotation predicted 38 genes involved in osmotic stress including the biosynthesis of osmoprotectants glycine-betaine, ectoine and osmoregulated periplasmic glucans. Genome analysis revealed also the versatility of the strain for emulsifying crude oil and metabolizing hydrocarbons. The ability of G11 to degrade crude oil components and to secrete a glycolipid biosurfactant with satisfying properties was experimentally confirmed and validated. Our results help to explain the exceptional capacity of G11 to survive at extreme desertic conditions, and highlight the metabolic features of this organism that has biotechnological and ecological potentialities.

Virgibacillus proomii and Bacillus mojavensis as probiotics in sea bass (Dicentrarchus labrax) larvae: effects on growth performance and digestive enzyme activities.

This study examined the effects of two probiotics (Virgibacillus proomii and Bacillus mojavensis) on the digestive enzyme activity, survival and growth of Dicentrarchus labrax at various ontogenetic stages in three separate experiments. These probiotics were incorporated as single or mixed into fish feed for a period of 60 days. The growth parameters, proximate composition of whole body, digestive enzymes and gut microbiology were monitored at regular. The increments in length and weight and the survival were significantly higher (P < 0.05), and the values of food conversions were significantly lower (P < 0.05) in fishes fed the probiotic. The administration of V. proomii and B. mojavensis in diet resulted in an increase (P > 0.05) in body ash and protein content and in the specific activity of phosphatase alkaline and amylase in the digestive tract of all the fishes. V. proomii and B. mojavensis persisted in the fish intestine and in the feed in high numbers during the feeding period (group 1: 5.8 × 10(4) CFU/ml, group 2: 9.6 × 10(4) CFU/ml, and group 3: 9.8 × 10(4) CFU/ml day 60). The two probiotics V. proomii and B. mojavensis were adequate for improved growth performance and survival and for healthy gut microenvironment of the host.

Effect of combined long-term starvation and γ-irradiation on membrane fatty acids and cell surface hydrophobicity of Salmonella enterica serovar Typhimurium.

This study was carried out to explore the adaptive mechanisms of Salmonella enterica serovar Typhimurium, in particular the implication of fatty acids (FA) in the remodeling of membrane lipid composition to overcome the combined effects of long-term starvation and γ-irradiation stresses. In addition, cell surface hydrophobicity was also evaluated. The bacterial strains (control and starved) were treated with a nonlethal γ-irradiation dose of 0.5 kGy and sublethal doses of 1 kGy. Gas chromatography analysis showed that the FA composition of starved and γ-irradiated cells was modified. However starvation combined with γ-irradiation induced more modifications in the FA composition than γ-irradiation or starvation alone. Indeed, the unsaturated FA-to-saturated FA ratio decreased significantly for both strains compared with γ-irradiated cells, as main consequence of the cyclic FA formation. Our results showed that starvation, irradiation, or combined stresses significantly influenced the hydrophobicity, and this may have affected the virulence state of Salmonella Typhimurium cells. This study represents one of the few to demonstrate the modifications on bacterial membrane as a cellular response to survive to the ionizing radiation combined with long-term starvation stress.

In silico and experimental characterization of a new polyextremophilic subtilisin-like protease from Microbacterium metallidurans and its application as a laundry detergent additive.

Considering the current growing interest in new and improved enzymes for use in a variety of applications, the present study aimed to characterize a novel detergent-stable serine alkaline protease from the extremophilic actinobacterium Microbacterium metallidurans TL13 (MmSP) using a combined in silico and experimental approach. The MmSP showed a close phylogenetic relationship with high molecular weight S8 peptidases of Microbacterium species. Moreover, its physical and chemical parameters computed using Expasy's ProtParam tool revealed that MmSP is hydrophilic, halophilic and thermo-alkali stable. 3D structure modelling and functional prediction of TL13 serine protease resulted in the detection of five characteristic domains: [catalytic subtilase domain, fibronectin (Fn) type-III domain, peptidase inhibitor I9, protease-associated (PA) domain and bacterial Ig-like domain (group 3)], as well as the three amino acid residues [aspartate (D182), histidine (H272) and serine (S604)] in the catalytic subtilase domain. The extremophilic strain TL13 was tested for protease production using agricultural wastes/by-products as carbon substrates. Maximum enzyme activity (390 U/gds) was obtained at 8th day fermentation on potato peel medium. Extracellular extract was concentrated and partially purified using ammonium sulfate precipitation methodology (1.58 folds purification fold). The optimal pH, temperature and salinity of MmSP were 9, 60 °C and 1 M NaCl, respectively. The MmSP protease showed broad pH stability, thermal stability, salt tolerance and detergent compatibility. In order to achieve the maximum stain removal efficacy by the TL 13 serine protease, the operation conditions were optimized using a Box-Behnken Design (BBD) with four variables, namely, time (15-75 min), temperature (30-60 °C), MmSP enzyme concentration (5-10 U/mL) and pH (7-11). The maximum stain removal yield (95 ± 4%) obtained under the optimal enzymatic operation conditions (treatment with 7.5 U/mL of MmSP during 30 min at 32 °C and pH9) was in good agreement with the value predicted by the regression model (98 ± %), which prove the validity of the fitted model. In conclusion, MmSP appears to be a good candidate for industrial applications, particularly in laundry detergent formulations, due to its high hydrophilicity, alkali-halo-stability, detergent compatibility and stain removal efficiency.

Pseudomonas rhizophila S211 as a microbial cell factory for direct bioconversion of waste cooking oil into medium-chain-length polyhydroxyalkanoates.

The present study examines the use of waste cooking oil (WCO) as a substrate for medium-chain-length polyhydroxyalkanoates (mcl-PHA) production by Pseudomonas rhizophila S211. The genome analysis revealed that the S211 strain has a mcl-PHA cluster (phaC1ZC2DFI) encoding two class II PHA synthases (PhaC1 and PhaC2) separated by a PHA depolymerase (PhaZ), a transcriptional activator (PhaD) and two phasin-like proteins (PhaFI). Genomic annotation also identified a gene encoding family I.3 lipase that was able to hydrolyze plant oils and generate fatty acids as favorable carbon sources for cell growth and PHA synthesis via ß-oxidation pathway. Using a three-variable Doehlert experimental design, the optimum conditions for mcl-PHA accumulation were achieved in 10% of WCO-based medium with an inoculum size of 10% and an incubation period of 48 h at 30 °C. The experimental yield of PHA from WCO was 1.8 g/L close to the predicted yield of 1.68 ± 0.14 g/L. Moreover, 1H nuclear magnetic resonance spectroscopy analysis confirmed the extracted mcl-PHA. Overall, this study describes P. rhizophila as a cell factory for biosynthesis of biodegradable plastics and proposes green and efficient approach to cooking oil waste management by decreasing the cost of mcl-PHA production, which can help reduce the dependence on petroleum-based plastics.

Extremophilic Bacterium Halomonas desertis G11 as a Cell Factory for Poly-3-Hydroxybutyrate-co-3-Hydroxyvalerate Copolymer's Production.

Microbial polyhydroxyalkanoates (PHA) are biodegradable and biocompatible bio-based polyesters, which are used in various applications including packaging, medical and coating materials. In this study, an extremophilic hydrocarbonoclastic bacterium, previously isolated from saline sediment in the Tunisian desert, has been investigated for PHA production. The accumulation of intracellular PHA granules in Halomonas desertis G11 was detected by Nile blue A staining of the colonies. To achieve maximum PHA yield by the strain G11, the culture conditions were optimized through response surface methodology (RSM) employing a Box-Behnken Design (BBD) with three independent variables, namely, substrate concentration (1-5%), inoculum size (1-5%) and incubation time (5-15 days). Under optimized conditions, G11 strain produced 1.5 g/L (68% of DCW) of PHA using glycerol as a substrate. Application of NMR (1H and 13C) and FTIR spectroscopies showed that H. desertis accumulated PHA is a poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV). The genome analysis revealed the presence of typical structural genes involved in PHBV metabolism including phaA, phaB, phaC, phaP, phaZ, and phaR, coding for acetyl-CoA acetyltransferase, acetoacetyl-CoA reductase, class I polyhydroxyalkanoates synthases, phasin, polyhydroxyalkanoates depolymerase and polyhydroxyalkanoates synthesis repressor, respectively. Glycerol can be metabolized to 1) acetyl-CoA through the glycolysis pathway and subsequently converted to the 3HB monomer, and 2) to propionyl-CoA via the threonine biosynthetic pathway and subsequently converted to the 3HV monomer. In silico analysis of PhaC1 from H. desertis G11 indicated that this enzyme belongs to Class I PHA synthase family with a "lipase box"-like sequence (SYCVG). All these characteristics make the extremophilic bacterium H. desertis G11 a promising cell factory for the conversion of bio-renewable glycerol to high-value PHBV.

Effect of Gamma Irradiation on Enhanced Biological Activities of Exopolysaccharide from Halomonas desertis G11: Biochemical and Genomic Insights.

In this work, a native exopolysaccharide (nEPS) produced by Halomonas desertis G11 isolated from a Tunisian extreme environment was modified by gamma irradiation. Characterization as well as the antioxidant and antitumor activities of nEPS and its gamma-irradiated derivatives (iEPSs) were comparatively evaluated. In vitro and in vivo antioxidant potentials were determined by using different methods and through different antioxidant enzymes. The antitumor activity was checked against a human colon cancer cell line. Analyses of the complete genome sequence were carried out to identify genes implicated in the production of nEPS. Thus, the genomic biosynthesis pathway and the export mechanism of nEPS were proposed. Analyses of irradiation data showed that iEPSs acquired new functional groups, lower molecular weights, and gained significantly (p < 0.05) higher antioxidant and antitumor abilities compared with nEPS. These findings provide a basis for using iEPSs as novel pharmaceutical agents for human therapies.

Genomic characterization of a polyvalent hydrocarbonoclastic bacterium Pseudomonas sp. strain BUN14.

Bioremediation offers a viable alternative for the reduction of contaminants from the environment, particularly petroleum and its recalcitrant derivatives. In this study, the ability of a strain of Pseudomonas BUN14 to degrade crude oil, pristane and dioxin compounds, and to produce biosurfactants, was investigated. BUN14 is a halotolerant strain isolated from polluted sediment recovered from the refinery harbor on the Bizerte coast, north Tunisia and capable of producing surfactants. The strain BUN14 was assembled into 22 contigs of 4,898,053 bp with a mean GC content of 62.4%. Whole genome phylogeny and comparative genome analyses showed that strain BUN14 could be affiliated with two validly described Pseudomonas Type Strains, P. kunmingensis DSM 25974T and P. chloritidismutans AW-1T. The current study, however, revealed that the two Type Strains are probably conspecific and, given the priority of the latter, we proposed that P. kunmingensis DSM 25974 is a heteronym of P. chloritidismutans AW-1T. Using GC-FID analysis, we determined that BUN14 was able to use a range of hydrocarbons (crude oil, pristane, dibenzofuran, dibenzothiophene, naphthalene) as a sole carbon source. Genome analysis of BUN14 revealed the presence of a large repertoire of proteins (154) related to xenobiotic biodegradation and metabolism. Thus, 44 proteins were linked to the pathways for complete degradation of benzoate and naphthalene. The annotation of conserved functional domains led to the detection of putative genes encoding enzymes of the rhamnolipid biosynthesis pathway. Overall, the polyvalent hydrocarbon degradation capacity of BUN14 makes it a promising candidate for application in the bioremediation of polluted saline environments.

Understanding the cumulative effects of salinity, temperature and inoculation size for the design of optimal halothermotolerant bioanodes from hypersaline sediments.

The main objective of this study was to understand the interaction between salinity, temperature and inoculum size and how it could lead to the formation of efficient halothermotolerant bioanodes from the Hypersaline Sediment of Chott El Djerid (HSCE). Sixteen experiments on bioanode formation were designed using a Box-Behnken matrix and response surface methodology to understand synchronous interactions. All bioanode formations were conducted on 6 cm2 carbon felt electrodes polarized at -0.1 V/SCE and fed with lactate (5 g/L) at pH 7.0. Optimum levels for salinity, temperature and inoculum size were predicted by NemrodW software as 165 g/L, 45 °C and 20%, respectively, under which conditions maximum current production of 6.98 ±â€¯0.06 A/m2 was experimentally validated. Metagenomic analysis of selected biofilms indicated a relative abundance of the two phyla Proteobacteria (from 85.96 to 89.47%) and Firmicutes (from 61.90 to 68.27%). At species level, enrichment of Psychrobacter aquaticus, Halanaerobium praevalens, Psychrobacter alimentaris, and Marinobacter hydrocarbonoclasticus on carbon-based electrodes was correlated with high current production, high salinity and high temperature. Members of the halothermophilic bacteria pool from HSCE, individually or in consortia, are candidates for designing halothermotolerant bioanodes applicable in the bioelectrochemical treatment of industrial wastewater at high salinity and temperature.

Dimethyl fumarate and monomethyl fumarate attenuate oxidative stress and mitochondrial alterations leading to oxiapoptophagy in 158N murine oligodendrocytes treated with 7ß-hydroxycholesterol.

Oxidative stress and mitochondrial dysfunction contribute to the pathogenesis of neurodegenerative diseases and favor lipid peroxidation, leading to increased levels of 7ß-hydroxycholesterol (7ß-OHC) which induces oxiapoptophagy (OXIdative stress, APOPTOsis, autoPHAGY). The cytoprotective effects of dimethylfumarate (DMF), used in the treatment of relapsing remitting multiple sclerosis and of monomethylfumarate (MMF), its main metabolite, were evaluated on murine oligodendrocytes 158 N exposed to 7ß-OHC (50 µM, 24 h) with or without DMF or MMF (25 µM). The activity of 7ß-OHC in the presence or absence DMF or MMF was evaluated on several parameters: cell adhesion; plasma membrane integrity measured with propidium iodide (PI), trypan blue and fluoresceine diacetate (FDA) assays; LDH activity; antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)); generation of lipid peroxidation products (malondialdehyde (MDA), conjugated dienes (CDs)) and protein oxidation products (carbonylated proteins (CPs)); reactive oxygen species (ROS) overproduction conducted with DHE and DHR123. The effect on mitochondria was determined with complementary criteria: measurement of succinate dehydrogenase activity, evaluation of mitochondrial potential (ΔΨm) and mitochondrial superoxide anions (O2●-) production using DiOC6(3) and MitoSOX, respectively; quantification of mitochondrial mass with Mitotracker Red, and of cardiolipins and organic acids. The effects on mitochondrial and peroxisomal ultrastructure were determined by transmission electron microscopy. Intracellular sterol and fatty acid profiles were determined. Apoptosis and autophagy were characterized by staining with Hoechst 33,342, Giemsa and acridine orange, and with antibodies raised against caspase-3 and LC3. DMF and MMF attenuate 7ß-OHC-induced cytotoxicity: cell growth inhibition; decreased cell viability; mitochondrial dysfunction (decrease of succinate dehydrogenase activity, loss of ΔΨm, increase of mitochondrial O2●- production, alteration of the tricarboxilic acid (TCA) cycle, and cardiolipins content); oxidative stress induction (ROS overproduction, alteration of GPx, CAT, and SOD activities, increased levels of MDA, CDs, and CPs); changes in fatty acid and cholesterol metabolism; and cell death induction (caspase-3 cleavage, activation of LC3-I in LC3-II). Ultrastructural alterations of mitochondria and peroxisomes were prevented. These results demonstrate that DMF and MMF prevent major dysfunctions associated with neurodegenerative diseases: oxidative stress, mitochondrial dysfunction, apoptosis and autophagy.

Biotin attenuation of oxidative stress, mitochondrial dysfunction, lipid metabolism alteration and 7ß-hydroxycholesterol-induced cell death in 158N murine oligodendrocytes.

Mitochondrial dysfunction and oxidative stress are involved in neurodegenerative diseases associated with an enhancement of lipid peroxidation products such as 7ß-hydroxycholesterol (7ß-OHC). It is, therefore, important to study the ability of 7ß-OHC to trigger mitochondrial defects, oxidative stress, metabolic dysfunctions and cell death, which are hallmarks of neurodegeneration, and to identify cytoprotective molecules. The effects of biotin were evaluated on 158N murine oligodendrocytes, which are myelin synthesizing cells, exposed to 7ß-OHC (50 µM) with or without biotin (10 and 100 nM) or α-tocopherol (positive control of cytoprotection). The effects of biotin on 7ß-OHC activities were determined using different criteria: cell adhesion; plasma membrane integrity; redox status. The impact on mitochondria was characterized by the measurement of transmembrane mitochondrial potential (ΔΨm), reactive oxygen species (ROS) overproduction, mitochondrial mass, quantification of cardiolipins and organic acids. Sterols and fatty acids were also quantified. Cell death (apoptosis, autophagy) was characterized by the enumeration of apoptotic cells, caspase-3 activation, identification of autophagic vesicles, and activation of LC3-I into LC3-II. Biotin attenuates 7ß-OHC-induced cytotoxicity: loss of cell adhesion was reduced; antioxidant activities were normalized. ROS overproduction, protein and lipid oxidation products were decreased. Biotin partially restores mitochondrial functions: attenuation of the loss of ΔΨm; reduced levels of mitochondrial O2•- overproduction; normalization of cardiolipins and organic acid levels. Biotin also normalizes cholesterol and fatty acid synthesis, and prevents apoptosis and autophagy (oxiapoptophagy). Our data support that biotin, which prevents oligodendrocytes damages, could be useful in the treatment of neurodegeneration and demyelination.

ZZ domain of dystrophin and utrophin: topology and mapping of a beta-dystroglycan interaction site.

Dystrophin forms part of a vital link between actin cytoskeleton and extracellular matrix via the transmembrane adhesion receptor dystroglycan. Dystrophin and its autosomal homologue utrophin interact with beta-dystroglycan via their highly conserved C-terminal cysteine-rich regions, comprising the WW domain (protein-protein interaction domain containing two conserved tryptophan residues), EF hand and ZZ domains. The EF hand region stabilizes the WW domain providing the main interaction site between dystrophin or utrophin and dystroglycan. The ZZ domain, containing a predicted zinc finger motif, stabilizes the WW and EF hand domains and strengthens the overall interaction between dystrophin or utrophin and beta-dystroglycan. Using bacterially expressed ZZ domain, we demonstrate a conformational effect of zinc binding to the ZZ domain, and identify two zinc-binding regions within the ZZ domain by SPOTs overlay assays. Epitope mapping of the dystrophin ZZ domain was carried out with new monoclonal antibodies by ELISA, overlay assay and immunohistochemistry. One monoclonal antibody defined a discrete region of the ZZ domain that interacts with beta-dystroglycan. The epitope was localized to the conformationally sensitive second zinc-binding site in the ZZ domain. Our results suggest that residues 3326-3332 of dystrophin form a crucial part of the contact region between dystrophin and beta-dystroglycan and provide new insight into ZZ domain organization and function.

Metabolomic fingerprint of Mentha rotundifolia L. Leaf tissues promotes this species as a potential candidate for sustainable production of biologically active molecules.

Background The Mentha rotundifolia L. (Lamiaceae family), is a medicinal herb used since the ancient times as an antiseptic, analgesic and anti-inflammatory agent. In the present work, metabolomic profiling of two Mentha rotundifolia L. ecotypes leaf tissues spontaneously growing in the North of Tunisia was achieved. Methods Phenolic contents (TPC, TFC and TTC) were assessed using colorimetric methods. Metabolomic profiling of leaf tissues extracts was assessed based on Gas Chromatography-Mass Spectrometry (GC/MS) analysis. The antioxidant ability of M. rotundifolia extracts was achieved based on two test systems namely DPPH and FRAP assays. Antimicrobial activity against a set of Gram negative and Gram positive bacteria was estimated by measuring ID, MIC and MBC values. Results Fifty metabolites were identified as belonging mainly to phenolics, fatty acids, terpenes, steroids and aldehydes classes with qualitative and quantitative variability. Most of the identified compounds are reputed bioactive with potent antioxidant, antimicrobial and anti-inflammatory among others effects. To confirm these findings common in vitro biological activities were achieved. The investigated extracts showed significant antioxidant abilities based on both 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Ferric reducing antioxidant potential (FRAP) assays. Furthermore, the extracts revealed promising antimicrobial ability against tested Gram+ and Gram- bacterial strains (ID: 12.5-14.5 mm, MIC: 3.125-25 (µg/mL), MBC: 6.25-100 (µg/mL)). Conclusions Based on our findings Mentha rotundifolia L. leaves extracts present a potential source of natural antioxidants and diverse bioactive compounds which could be used in green pharmacy, food preservation, alternative medicine and natural therapies.

Two New Secreted Proteases Generate a Casein-Derived Antimicrobial Peptide in Bacillus cereus Food Born Isolate Leading to Bacterial Competition in Milk.

Milk and dairy products harbor a wide variety of bacterial species that compete for both limited resources and space. Under these competitive conditions, bacteria develop specialized mechanisms to protect themselves during niche colonization and nutrient acquisition processes. The bacterial antagonism mechanisms include the production of antimicrobial agents or molecules that facilitate competitor dispersal. In the present work, a bacterial strain designated RC6 was isolated from Ricotta and identified as Bacillus cereus. It generates antimicrobial peptide (AMP) when grown in the presence of casein. The AMP was active against several species of Bacillus and Listeria monocytogenes. MALDI-TOF analysis of the RP-HPLC purified fractions and amino acid sequencing revealed a molecular mass of 751 Da comprised of a 6-residue sequence, YPVEPF. BLAST analysis showed that the AMP corresponds to the fractions 114-119 of bovine ß-casein and represents the product of a specific proteolysis. Analysis of the purified proteolytic fractions from the B. cereus RC6 culture supernatant indicated that the presence of at least two different endoproteases is crucial for the generation of the AMP. Indeed, we were able to identify two new candidate endoproteases by means of genome sequencing and functional assignment using a 3D structural model and molecular docking of misannotated hypothetical proteins. In this light, the capacity of B. cereus RC6 to generate antimicrobial peptides from casein, through the production of extracellular enzymes, presents a new model of antagonistic competition leading to niche colonization. Hence, as a dairy product contaminant, this strategy may enable proteolytic B. cereus RC6 niche specialization in milk matrices.

Pathological pattern of Mdx mice diaphragm correlates with gradual expression of the short utrophin isoform Up71.

Utrophin gene is transcribed in a large mRNA of 13 kb that codes for a protein of 395 kDa. It shows amino acid identity with dystrophin of up to 73% and is widely expressed in muscle and non-muscle tissues. Up71 is a short utrophin product of the utrophin gene with the same cysteine-rich and C-terminal domains as full-length utrophin (Up395). Using RT-PCR, Western blots analysis, we demonstrated that Up71 is overexpressed in the mdx diaphragm, the most pathological muscle in dystrophin-deficient mdx mice, compared to wild-type C57BL/10 or other mdx skeletal muscles. Subsequently, we demonstrated that this isoform displayed an increased expression level up to 12 months, whereas full-length utrophin (Up395) decreased. In addition, beta-dystroglycan, the transmembrane glycoprotein that anchors the cytoplasmic C-terminal domain of utrophin, showed similar increase expression in mdx diaphragm, as opposed to other components of the dystrophin-associated protein complex (DAPC) such as alpha-dystrobrevin1 and alpha-sarcoglycan. We demonstrated that Up71 and beta-dystroglycan were progressively accumulated along the extrasynaptic region of regenerating clusters in mdx diaphragm. Our data provide novel functional insights into the pathological role of the Up71 isoform in dystrophinopathies.

Subspace-based self-interference cancellation for full-duplex MIMO transceivers.

This paper addresses the self-interference (SI) cancellation at baseband for full-duplex MIMO communication systems in consideration of practical transmitter imperfections. In particular, we develop a subspace-based algorithm to jointly estimate the SI and intended channels and the nonlinear distortions. By exploiting the covariance and pseudo-covariance of the received signal, we can increase the dimension of the received signal subspace while keeping the dimension of the signal subspace constant, and hence, the proposed algorithm can be applied to most of full-duplex MIMO configurations with arbitrary numbers of transmit and receive antennas. The channel coefficients are estimated, up to an ambiguity term, without any knowledge of the intended signal. A joint detection and ambiguity identification scheme is proposed. Simulation results show that the proposed algorithm can properly estimate the channel with only one pilot symbol and offers superior SI cancellation performance.

Association of SNP3 polymorphism in the apolipoprotein A-V gene with plasma triglyceride level in Tunisian type 2 diabetes.

BACKGROUND: Apolipoprotein A-V (Apo A-V) gene has recently been identified as a new apolipoprotein involved in triglyceride metabolism. A single nucleotide polymorphism (SNP3) located in the gene promoter (-1131) was associated with triglyceride variation in healthy subjects. In type 2 diabetes the triglyceride level increased compared to healthy subjects. Hypertriglyceridemia is a risk factor for coronary artery disease. We aimed to examine the interaction between SNP3 and lipid profile and coronary artery disease (CAD) in Tunisian type 2 diabetic patients. RESULTS: The genotype frequencies of T/T, T/C and C/C were 0.74, 0.23 and 0.03 respectively in non diabetic subjects, 0.71, 0.25 and 0.04 respectively in type 2 diabetic patients. Triglyceride level was higher in heterozygous genotype (-1131 T/C) of apo A-V (p = 0.024). Heterozygous genotype is more frequent in high triglyceride group (40.9%) than in low triglyceride group (18.8%); p = 0.011. Despite the relation between CAD and hypertriglyceridemia the SNP 3 was not associated with CAD. CONCLUSION: In type 2 diabetic patients SNP3 is associated with triglyceride level, however there was no association between SNP3 and coronary artery disease.