The role of phadiatop in the screening of respiratory allergy

Phadiatop is a new in vitro screening test for respiratory allergy. This test, based on the RAST procedure, detects in serum, the presence of specific IgE to a mixture of common inhalent allergens. Among 70 patients (26 children and 44 adults) consulting for respiratory syndrome, Phadiatop was positive in 31 cases. There were a good correlation between this new test and skin tests (59% for adults and 92% for children), total IgE (70% for adults and 65% for children) and RAST (93% for adults and 96% for children). Phadiatop, with a specificity of 100%, a sensitivity of 82% (76% for adults and 92% for children) and an efficiency of 90% (86% for adults and 96% for children), is a more accurate test than total IgE and could be an excellent in vitro screening test for respiratory allergy.     

Comparative study on the antibiotic susceptibility and plasmid profiles of Vibrio alginolyticus strains isolated from four Tunisian marine biotopes

The antibiotic resistance patterns and the plasmids profiles of the predominant etiological agent responsible for vibriosis in Tunisia, V. alginolyticus were studied to contribute to control their spread in some Mediterranean aquaculture farms and seawater. The sixty-nine V. alginolyticus strains isolated from different marine Tunisian biotopes (bathing waters, aquaculture and conchylicole farms and a river connected to the seawater during the cold seasons) were multi-drug resistant with high resistance rate to ampicillin, kanamycin, doxycyclin, erythromycin, imipinem, and nalidixic acid. The multiple resistance index ranged from 0.3 to 0.7 for the isolates of Khenis, from 0.5 to 0.8 for those of Menzel Jmil, from 0.5 to 0.75 (Hergla) and from 0.3 to 0.7 for the isolates of Oued Soltane. The high value of antibiotic resistance index was recorded for the V. alginolyticus population isolated from the fish farm in Hergla (ARI?=?0.672) followed by the population isolated from the conchylicole station of Menzel Jmil (ARI?=?0.645). The results obtained by the MIC tests confirmed the resistance of the V. alginolyticus to ampicillin, erythromycin, kanamycin, cefotaxime, streptomycin and trimethoprim. Plasmids were found in 79.48?% of the strains analyzed and 30 different plasmid profiles were observed. The strains had a high difference in the size of plasmids varying between 0.5 and 45?kb. Our study reveals that the antibiotic-resistant bacteria are widespread in the aquaculture and conchylicole farm relatively to others strains isolated from seawater.     

In-vitro anti-<Emphasis Type="Italic">Vibrio</Emphasis> spp. activity and chemical composition of some Tunisian aromatic plants

The chemical composition of five aromatic plants (Mentha longifolia, M. pulegium, Eugenia caryophyllata, Thymus vulgaris and Rosmarinus officinalis) frequently used in food preparation in Tunisia was analysed by GC-MS. The antimicrobial effect of the essential oils obtained from these plants was tested against Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio fluvialis strains. Thyme oil exhibited a high level of antimicrobial activities against Vibrio spp. strains. The diameter of the zones of growth inhibition for V. parahaemolyticus species was interestingly high (ranging from 14.66 to 28 mm). The MIC and MBC values were interestingly low for thyme oil (MIC 0.078–0.156 mg/ml) and (MBC >0.31–1.25 mg/ml). These results showed that these plants especially thyme and clove, can be to be used for seafood preparation to protect against contamination by Vibrio spp. strains. An erratum to this article can be found at     

Pyrolysis characteristics and kinetics of Arundo donax using thermogravimetric analysis

The increase of the price of fossil means, as well as their programmed disappearing, contributed to increase among appliances based on biomass and energy crops. The thermal behavior of Arundo donax by thermogravimetric analysis was studied under inert atmosphere at heating rates ranging from 5 to 20 °C min⁻¹ from room temperature to 750 °C. Gaseous emissions as CO₂, CO and volatile organic compounds (VOC) were measured and global kinetic parameters were determined during pyrolysis with the study of the influence of the heating rate. The thermal process describes two main phases. The first phase named active zone, characterizes the degradation of hemicellulose and cellulose polymers. It started at low temperature (200 °C) comparatively to wood samples and was finished at 350 °C. The pyrolysis of the lignin polymer occurred during the second phase from 350 to 750 °C, named passive zone. Carbon oxides are emitted during the active zone whereas VOC are mainly formed during the passive zone. Mass losses, mass loss rates and emission factors were strongly affected by the variation of the heating rate in the active zone. It was found that the global pyrolysis of A. donax can be satisfactorily described using global independent reactions model for hemicellulose and cellulose in the active zone. The activation energy for hemicellulose was not affected by a variation of the heating rate with a value close to 110 kJ mol⁻¹ and presented a reaction order close to 0.5. An increase of the heating rate decreased the activation energy of the cellulose. However, a first reaction order was observed for cellulose decomposition. The experimental results and kinetic parameters may provide useful data for the design of pyrolytic processing system using A. donax as feedstock.     

Phenotypic characterization and RAPD fingerprinting of Vibrio parahaemolyticus and Vibrio alginolyticus isolated during Tunisian fish farm outbreaks

The genus Vibrio is characterized by a large number of species and some of them are human pathogens causing gastrointestinal and wound infections through the ingestion or manipulation of contaminated fishes and shellfish including Vibrio parahaemolyticus and Vibrio alginolyticus. In this study, we reported the phenotypic and molecular characterization of 9 V. parahaemolyticus and 27 V. alginolyticus strains isolated from outbreaks affecting cultured Gilthead sea bream (Sparus aurata L.) and Sea bass (Dicentrarchus labrax) along the Tunisian coast from 2008 to 2009. All isolates were tested for the presence of DNase, caseinase, protease, lipase, amylase, gelatinase, hemolytic activity and antibacterial resistance to different drugs. Randomly amplified polymorphic DNA was used to examine the genetic relatedness among the V. parahaemolyticus and V. alginolyticus strains.     

Biological activities of the essential oils and methanol extract of tow cultivated mint species (<Emphasis Type="Italic">Mentha longifolia</Emphasis> and <Emphasis Type="Italic">Mentha pulegium</Emphasis>) used in the Tunisian folkloric medicine

The composition of the essential oils and methanolic extracts of two cultivated mint species (M. longifolia and M. pulegium), as well as the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract of Mentha longifolia and Mentha pulegium were compared. GC-MS analysis of the essential oil identified 41 compounds constituting 96.66 and 96.13% of the total oil from M. longifolia and M. pulegium, respectively. The later oils were rich on pulegone (47.15 and 61.11%, respectively). Moreover, 1,8 cineole (11.54%), menthone (10.7%), α-pinene (3.57%), α-terpineol (3.17%) and d-cadinene (3.53%) were only present in M. longifolia oil, while isomenthone (17.02%), and piperitone (2.63%), were characteristic of M. pulegium oil. Shoot extract of the two species showed significantly different contents in total polyphenols (89.1 and 37.41 mg GAE/g DW), flavonoids (63.93 and 33.83 mg CE/g DW) and tannins (1.47 and 3.07 mg CE/g DW), respectively in M. longifolia and M. pulegium. The essential oils showed strong antimicrobial activity against all 16 microorganisms tested, whereas the methanol extracts were inactive. Moreover, the essential oils showed higher antioxidant activity than the methanolic extracts against the DPPH and superoxide radical scavenging. In fact, antioxidant activities of the oils were the same for both M. longifolia and M. pulegium against DPPH (IC₅₀ = 9 and 10 μg/ml, respectively) and 2-fold and 4-fold higher than shoot extracts (IC₅₀ = 20 and 48 μg/ml, respectively). Moreover, both oils showed the same antioxidative abilities as compared to the positive control (butylated hydroxytoluene). In the same way, the capacity to inhibit superoxide anion was very significant for the two oils (0.1 μg/ml for M. longifolia and 0.11 μg/ml for M. pulegium).     

Quantitative study, identification and antibiotics sensitivity of someVibrionaceae associated to a marine fish hatchery

This study characterises the bacteria associated with a marine hatchery in Tunisian coastal marine waters. Presumptive vibrios (TCBS agar) and heterotrophic aerobic microflora (CFU) were studied at different stages within the hatchery: seawater, batches of algal cultures, rotifers andArtemia culture tanks. The bacterial strains were isolated on TCBS Agar plates and described using different bacteriological tests (standardised micromethods “API 20 E Strips”, exoenzymes production, growth at different temperatures, pH and salinity, vibriostatic agent O/129 and antibiotics susceptibility). Two dominant genera of bacteria were found (Vibrio andAeromonas) associated with some strains of thePseudomonadaceae family.Vibrio alginolyticus was the dominant bacteria (75% of total isolates) found in rotifers (Brachionus plicatilis) andArtemia cultures (Artemia salina). In larvae rearing tanks, an increase ofVibrionaceae was noted after larvae were fed withArtemia. Most of the studied bacteria used the skin mucus ofSparus aurata larvae as their sole source of carbon. All theV. alginolyticus strains were β-haemolytic, hydrolyse the DNA and were susceptible to several tested antibiotics.     

Changeability in Retama raetam essential oils chemical composition,antioxidant and antimicrobial properties as affected by the physiological stage

Abstract

Retama raetam essential oils (EOs) composition and biological activities were assessed during three developmental periods. The essential oil yield varied significantly among the developmental stages and the optimal was detected at the fresh fruiting stage (0.34%). In addition, EOs composition varied significantly (p < 0.05) according to the different developmental stages. In fact, 2-Methoxy-4-vinylphenol, linalool, and 1-octen-3-ol were the main compounds in the vegetative, flowering, and the fresh fruiting stages, respectively. Developmental stage had also a strong effect on EOs antioxidant and antimicrobial activities. In fact, during the fresh fruiting stage, IC₅₀ and EC₅₀ values of the antioxidant assays were 2 to 3 times inferior to all others stages. Concerning the determination of the diameter of inhibition, a slight to high antimicrobial activity was revealed against 12 bacteria and 4 yeasts. Once again, EOs from the fresh fruiting stage had higher bactericidal effect than those from the flowering and vegetative ones (IZ varied from 10 to 13 mm). The results of this investigation showed for the first time the high accumulation of EOs at the early stages of fruit development making the fresh fruiting optimal stage for the extraction of powerful antioxidant and antimicrobial EOs.     

Mammary gland development: Role of basal myoepithelial cells

Mammary epithelium is organized as a bilayer with a layer of luminal secretory cells and a layer of basal myoepithelial cells. To dissect the specific functions of these two major compartments of the mammary epithelium in mammary morphogenesis we have used genetically modified mice carrying transgenes or conditional alleles whose expression or ablation were cell-type specific. Basal cells are located in close proximity to mammary stroma and directly interact with the extracellular matrix (basement membrane) during all their lifespan. On the contrary, luminal secretory cells during early stages of the postnatal mammary development have only limited contacts with basement membrane and become exposed to the extracellular matrix only during late developmental stages at the end of pregnancy and in lactation. Consistently perturbation of beta1-integrin function specifically in the luminal layer of the mammary epithelium, did not interfere with mammary morphogenesis until the second part of pregnancy but led to impaired secretory differentiation and lactation. On the contrary, ablation of beta1-integrin gene in the basal mammary epithelial cells resulted in a more precocious phenotype: disorganized branching in young virgin animals and a complete arrest of lobuloalveolar development. Further, a constitutive activation of beta-catenin signaling due to expression of N-terminally truncated (stabilized) beta-catenin specifically in basal myoepithelial cells resulted in accelerated differentiation of luminal secretory cells in pregnancy, precocious postlactational involution, increased angiogenesis and development of mammary tumors. Altogether these data suggest that basal mammary epithelial cells can affect growth and differentiation of luminal secretory cells, have an impact on the epithelium-stroma relationships and, thereby, play an important role in the process of mammary morphogenesis and differentiation.     

Variability of phenolic composition and biological activities of two Tunisian halophyte species from contrasted regions

The present study consists in evaluating the inter- and intraspecific variability of phenolic contents and biological capacities of Limoniastrum monopetalum L. and L. guyonianum Boiss. extracts. Ultimately, they were subjected to HPLC for phenolic identification. Results showed a great variation of phenolic content as function of species and localities. In fact, L. guyonianum extracts (El Akarit) contained the highest polyphenol (57 mg GAE g^?1 DW), flavonoid (9.47 mg CE g^?1 DW) and condensed tannin contents (106.58 mg CE g^?1 DW). These amounts were accompanied by the greatest total antioxidant activity (128.53 mg GAE g^?1 DW), antiradical capacity (IC₅₀ = 4.68 μg/ml) and reducing power (EC₅₀ = 120 μg/ml). In addition, L. monopetalum and L. guyonianum extracts exhibited an important and variable antibacterial activity with a diameter of inhibition zone ranging from 6.00 to 14.83 mm. Furthermore, these extracts displayed considerable antifungal activity. L. monopetalum extracts (Enfidha) showed the strongest activity against Candida glabrata and C. krusei with a diameter exceeding 12 mm. The phytochemical investigation of these extracts confirmed the variability of phenolic composition, since the major phenolic compound varied as a function of species and locality. These findings suggest that these two halophytes may be a new source of natural antioxidants that are increasingly important for human consumption, as well as for agro-food, cosmetic and pharmaceutical industries.