ABSTRACT
In order to identify lactic acid bacteria [LAB] associated with traditional goat cheeses and to assess their probiotic effect, chemical and microbiological analysis were carried out on seven products collected from different Lebanese regions: Laban [L], Labneh Ambarise[LA], Labneh Serdalli [LS], Jebneh Darfieh [JD], Keshek [K], Shanklish [Sh] and Labneh Darfiyeh [LD]. These samples were analysed for their pH and acidity. The isolation of lactic acid bacteria was achieved using two selective media, namely MRS and M17 agar. Isolated strains were identified according to morphology, Gram staining, catalase and oxydase, ammonia production from arginine, carbon dioxide production from glucose, growth in MRS broth at 10degree C and 45degree C, salt tolerance [2, 4 and 6.5% of NaCl], sugar fermentation with API [Analytical Profile Index] system methods [50CHL and 20Strep]. The probiotic potential of isolates to inhibit pathogenic bacteria [Salmonella, Staphylococcus aureus and E. coli], their survival at different pH [1, 2, 3 and 7.2], the time needed to reach acidification end point in full and skimmed milk were assessed. Labneh Ambarise and Labneh Darfiyeh had an average pH of 4+/-0.5 and a titratable acidity of 2%+/-0.1 [w/w], while the average pH and titrable acidity of Darfiyeh cheese were 5.22 and 0.62 respectively. The presence of LAB in one year old samples preserved in olive oil could not be detected. Twenty five strains were isolated and identified from different samples, where nine of them belong to Lactobacillus plantarum [L2, Sh2, K2, K3, K4, K5, LS1, LS3 and LS4], three are Lactobacillus paracasei spp. paracasei [Sh3, LS2 and LS5] and five are Leuconostoc mesenteroides spp. dextranicum 2 [JD1, JD2, JD3, JD4 and JD5]; four colonies are suspected to be Lactobacillus casei [L1, Sh4, K1 and K6] and four others are probably yeasts [L3, L4, L5 and L6]. Identified strains showed a capacity to produce antimicrobial substances with maximum inhibition diameters of 20 mm against Salmonella [K1, Sh4, LS1 and JD1], 21 mm and 19 mm for L2 against Escherichia coli and Staphylococcus aureus, respectively. The microorganisms survival rate in simulated gastric juice [SGJ] varied between 50% and 93% at pH 3 [Sh3, K2, LS2, LS5, JD1 and JD3]. Their growth was inhibited at pH 1 [0.05% to 0.08%]; only JD1 and JD3 showed more then 50% of viability at pH 2. The time needed for milk acidification had an average of more than 10 h exceeding the time required by yogurt starter cultures [5 h]. The Jebneh Darfieh sample, rich in Leuconostoc mesenteroides, showed the most interesting characteristics of cell viability at pH 2 [50% for JD1 and JD2] and a maximum of 20 mm of inhibition against Salmonella. It could be used as a natural source of probiotic. The isolates of the samples Laban, Shanklish, Keshek and Labneh Serdalli [L. plantarum and L. paracasei mainly] were more sensitive to high acidity [pH=2], but showed good antimicrobial activity against pathogens. Microencapsulation is probably required to protect them from harsh conditions. Further tests are needed to determine the exact identity of some strains and the nature of secreted substances responsible of the probiotic effects
ABSTRACT
The UDP-glucuronosyltransferase 1A1 gene that encode the enzyme UGT1A1 responsible for glucuronidation undergoes several variations that may affect the enzymatic activity or expression and which are the cause of metabolic disorders related to the glucuronidation of bilirubin, such as Gilbert's syndrome and Crigler Najjar's syndrome. Among the most common variations, there is the repeat polymorphism A [TA] n TAA in TATA box and biallelic mutation G211A in exon 1. We consider in this work to determine their frequencies in a healthy population. The polymorphism A [TA] n TAA showed that genotype [TA7/TA7] was described as being associated with Gilbert's syndrome and was encountered in 11% of the population studied. This percentage is close to the value described in the Caucasian population, estimated at 10%. Concerning the polymorphism G211A, our results show that the mutated allele is encountered in 15.7% of our study population. This frequency differs greatly from that reported for Caucasians and Afro-Americans but it is similar to that perceived at the Japanese. All these results suggest that the Tunisian population appears to be heterogeneous view UGT1A1 gene mutation status. Regarding the origins and distribution of such polymorphisms in our population, the study reveals a high haplotypic heterogeneity and emergence of the particular haplotype [TA] 6-G considered ancestral. The comparison of the haplotype structure generally leads to the development of a hypothetical tree of the origin and spread of different haplotypes
ABSTRACT
Autism is a neurodevelopmental disorder, which manifests itself in early childhood. It is characterized by impairments in social interaction, communication and the presence of stereotyped patterns of behaviour. In 10 to 15 percent of autistic patients, it is possible to identify chromosomal abnormalities: non specific ones or those specific to a particular syndrome. In this study we report a literature review of these cytogenetic aberrations and we insist on the interest of the autistic patients karyotype analysis