Large-scale analysis of NBS domain-encoding resistance gene analogs in Triticeae

Proteins containing nucleotide binding sites (NBS) encoded by plant resistance genes play an important role in the response of plants to a wide array of pathogens. In this paper, an in silico search was conducted in order to identify and characterize members of NBS-encoding gene family in the tribe of Triticeae. A final dataset of 199 sequences was obtained by four search methods. Motif analysis confirmed the general structural organization of the NBS domain in cereals, characterized by the presence of the six commonly conserved motifs: P-loop, RNBS-A, Kinase-2, Kinase-3a, RNBS-C and GLPL. We revealed the existence of 11 distinct distribution patterns of these motifs along the NBS domain. Four additional conserved motifs were shown to be significantly present in all 199 sequences. Phylogenetic analyses, based on genetic distance and parsimony, revealed a significant overlap between Triticeae sequences and Coiled coil-Nucleotide binding site-Leucine rich repeat (CNL)-type functional genes from monocotyledons. Furthermore, several Triticeae sequences belonged to clades containing functional homologs from non Triticeae species, which has allowed for these sequences to be functionally assigned. The findings reported, in this study, will provide a strong groundwork for the isolation of candidate R-genes in Triticeae crops and the understanding of their evolution.     

Update of the spectrum of GJB2 gene mutations in Tunisian families with autosomal recessive nonsyndromic hearing loss

Hearing loss is the most frequent sensory disorder. It affects 3 in 1000 newborns. It is genetically heterogeneous with 60 causally-related genes identified to date. Mutations in GJB2 gene account for half of all cases of non-syndromic deafness. The aim of this study was to determine the relative frequency of GJB2 allele variants in Tunisia. In this study, we screened 138 patients with congenital hearing loss belonging to 131 families originating from different parts of Tunisia for mutations in GJB2 gene. GJB2 mutations were found in 39% of families (51/131). The most common mutation was c.35delG accounting for 35% of all cases (46/131). The second most frequent mutation was p.E47X present in 3.8% of families. Four identified mutations in our cohort have not been reported in Tunisia; p.V37I, c.235delC, p.G130A and the splice site mutation IVS1+1G>A (0.76%). These previously described mutations were detected only in families originating from Northern and not from other geographical regions in Tunisia. In conclusion we have confirmed the high frequency of c.35delG in Tunisia which represents 85.4% of all GJB2 mutant alleles. We have also extended the mutational spectrum of GJB2 gene in Tunisia and revealed a more pronounced allelic heterogeneity in the North compared to the rest of the country.     

Molecular and biochemical characterization of a novel intronic single point mutation in a Tunisian family with glycogen storage disease type III

Genetic deficiency of the glycogen debranching enzyme causes glycogen storage disease type III, an autosomal recessive inherited disorder. The gene encoding this enzyme is designated as AGL gene. The disease is characterized by fasting hypoglycemia, hepatomegaly, growth retardation, progressive myopathy and cardiomyopathy. In the present study, we present clinical features and molecular characterization of two consanguineous Tunisian siblings suffering from Glycogen storage disease type III. The full coding exons of the AGL gene and their corresponding exon–intron boundaries were amplified for the patients and their parents. Gene sequencing identified a novel single point mutation at the conserved polypyrimidine tract of intron 21 in a homozygous state (IVS21-8A>G). This variant cosegregated with the disease and was absent in 102 control chromosomes. In silico analysis using online resources showed a decreased score of the acceptor splice site of intron 21. RT-PCR analysis of the AGL splicing pattern revealed a 7 bp sequence insertion between exon 21 and exon 22 due to the creation of a new 3′ splice site. The predicted mutant enzyme was truncated by the loss of 637 carboxyl-terminal amino acids as a result of premature termination. This novel mutation is the first mutation identified in the region of Bizerte and the tenth AGL mutation identified in Tunisia. Screening for this mutation can improve the genetic counseling and prenatal diagnosis of GSD III.     

Toxicities effects of pharmaceutical, olive mill and textile wastewaters before and after degradation by Pseudomonas putida mt-2

Background  

Removal of numerous classes of chemical pollutants from the industrial wastewater such as textile, pharmaceutical and olive mill using conventional wastewater treatment, is incomplete and several studies suggested that improvement of this situation would require the application of biological treatment techniques. Dyes, polyphenols and drugs are an environmental pollutants extremely toxics to plants and other living organisms including humans. These effluents were previously treated by Pseudomonas putida. The main of this work was to evaluate the in vivo toxicity of the three wastewaters.     

Preparation and testing of Sardinella protein hydrolysates as nitrogen source for extracellular lipase production by Rhizopus oryzae

Various fish protein hydrolysates (FPH) from sardinella (Sardinella aurita) were used as nitrogen sources for the production of extracellular lipase by the filamentous fungus Rhizopus oryzae. The best results were obtained with defatted meat–fish protein hydrolysates (DMFPH), indicating the presence in the lipid fraction of some constituents which may repress lipase synthesis. Furthermore, it was found that the extensive hydrolysis of fish proteins resulted in a higher lipase production. The use of 40 g DMFPH l^–1 for the growth of Rhizopus oryzae in medium R1 resulted in a lipase production of 394 U ml^–1, higher than the yield obtained with standard soy peptone as nitrogen source (373 U ml^–1). The most appropriate medium for the growth and the production of lipase is composed only of 24 g DMFPH l^–1 and 10 g glucose l^–1, indicating that the strain can obtain its nitrogen and salts requirements directly from fish substrate.     

Fitness cost due to herbicide resistance may trigger genetic background evolution

This article investigates the possible existence of mechanisms counterbalancing the negative pleiotropic effects on development and reproduction that are conferred by alleles responsible for herbicide resistance in the weed Alopecurus myosuroides. We considered three herbicide-resistant, mutant acetyl-coenzyme A carboxylase (ACCase) alleles, Leu1781, Asn2041, and Gly2078, found in eight resistant populations. Of these, Gly2078 is the only allele with a known fitness cost. We compared plants homozygous for wild-type ACCase alleles that were siblings of plants carrying a given mutant resistant ACCase allele with plants from three populations where resistance did not evolve. In each of two series of experiments, we measured germination dynamics, seedling vigor, plant height, vegetative biomass, and seed production. The wild-type siblings of plants carrying Gly2078 performed better in the field, on average, than wild-type plants that were sibling of plants carrying other mutant ACCase alleles, and particularly those carrying Leu1781. We propose that rapid evolution of the genetic background of plants from the populations where the Gly2078 allele originally arose could partially counterbalance Gly2078 fitness cost, enhancing the spread of the resistant genotypes.     

Matrix metalloproteinase 3 and 9 as genetic biomarkers for the occurrence of cardiovascular complications in coronary artery disease: a prospective cohort study

Molecular Biology Reports - Matrix metalloproteinases (MMPs) are widely expressed in atherosclerosis lesions. The disequilibrium of MMPs driving to an overexpression or a lack of its level can be...     

Whole Exome Sequencing Identifies Mutations in Usher Syndrome Genes in Profoundly Deaf Tunisian Patients

Usher syndrome (USH) is an autosomal recessive disorder characterized by combined deafness-blindness. It accounts for about 50% of all hereditary deafness blindness cases. Three clinical subtypes (USH1, USH2, and USH3) are described, of which USH1 is the most severe form, characterized by congenital profound deafness, constant vestibular dysfunction, and a prepubertal onset of retinitis pigmentosa. We performed whole exome sequencing in four unrelated Tunisian patients affected by apparently isolated, congenital profound deafness, with reportedly normal ocular fundus examination. Four biallelic mutations were identified in two USH1 genes: a splice acceptor site mutation, c.2283-1G>T, and a novel missense mutation, c.5434G>A (p.Glu1812Lys), in MYO7A, and two previously unreported mutations in USH1G, i.e. a frameshift mutation, c.1195_1196delAG (p.Leu399Alafs*24), and a nonsense mutation, c.52A>T (p.Lys18*). Another ophthalmological examination including optical coherence tomography actually showed the presence of retinitis pigmentosa in all the patients. Our findings provide evidence that USH is under-diagnosed in Tunisian deaf patients. Yet, early diagnosis of USH is of utmost importance because these patients should undergo cochlear implant surgery in early childhood, in anticipation of the visual loss.