Effects of chloramphenicol on brain energy metabolism using 31P spectroscopy: influences on sleep-wake states in rat

Effects of chloramphenicol (antibiotic inhibiting complex-1 of respiratory chain) and thioamphenicol (TAP, a structural analog of CAP inactive on complex-1) were examined on cerebral energy metabolites and sleep-wake cycle architecture in rat. In the first group, animals were chronically equipped with a cranial surface resonator and ³¹P spectroscopic measurements were performed using a 2 T magnetic resonance spectrometer (operating frequency 34.46 MHz). CAP administration (400 mg/kg, tail vein, light period) induced deficits in phosphocreatine (−30%, p  < 0.01) and ATP (−40%, p  < 0.01), whereas TAP (400 mg/kg) had no effect. In the second group, animals were chronically implanted with polygraphic electrodes for EEG and electromyogram recordings. CAP administered intraperitoneally at light-onset reduced rapid-eye movement (REM) sleep (−60% in the first 6 h of light period, p  < 0.01), increased waking state (+65% in the first 6 h of light period, p  < 0.01), and slightly affected slow-wave sleep (SWS). During waking state, θ and σ power bands of the EEG were, respectively, increased and decreased ( p  < 0.05). During SWS, delta power band was reinforced ( p  < 0.05), while θ, α, and σ bands were decreased ( p  < 0.05). No changes occurred during REM sleep. TAP had no effect on sleep-wake states and spectral components of the EEG. Overall, these data indicate that REM sleep occurrence is linked to an aerobic production of ATP.     

Genetic and molecular analysis of the CLDN14 gene in Moroccan family with non-syndromic hearing loss

BACKGROUND:

Hearing loss is the most prevalent human genetic sensorineural defect. Mutations in the CLDN14 gene, encoding the tight junction claudin 14 protein expressed in the inner ear, have been shown to cause non-syndromic recessive hearing loss DFNB29.

AIM:

We describe a Moroccan SF7 family with non-syndromic hearing loss. We performed linkage analysis in this family and sequencing to identify the mutation causing deafness.

MATERIALS AND METHODS:

Genetic linkage analysis, suggested the involvement of CLDN14 and KCNE1 gene in deafness in this family. Mutation screening was performed using direct sequencing of the CLDN14 and KCNE1 coding exon gene.

RESULTS:

Our results show the presence of c.11C>T mutation in the CLDN14 gene. Transmission analysis of this mutation in the family showed that the three affected individuals are homozygous, whereas parents and three healthy individuals are heterozygous. This mutation induces a substitution of threonine to methionine at position 4.

CONCLUSION:

These data show that CLDN14 gene can be i mplicated in the development of hearing loss in SF7 family; however, the pathogenicity of c.11C>T mutation remains to be determined.     

The rs9939609 polymorphism in the fat mass and obesity associated (FTO) gene is associated with obesity in Tunisian population

Abstract

Context: Variations in the fat mass and obesity-associated gene (FTO) has been associated with obesity in many populations, but the results are conflicting.

Objective: The aim of this study was to evaluate the effect of the rs9939609 polymorphism in the FTO gene on obesity risk and plasma leptin, adiponectin, insulin and lipid concentrations in Tunisians.

Materials and methods: Four hundred and ninety-four subjects with obesity and 334 non-obese participated in this study. The rs9939609 (T/A) genotype was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results: Significant differences in genotype frequencies were observed between cases and controls. In the separate analysis by gender, the association between the AA genotype and obesity was statistically significant in women but not in men. After stratification by obesity class this association remains only with obesity class III.

Discussion: Our study is in agreement with studies on Caucasian, Portuguese and Cebu Filipino populations where a gender-specific association was found between rs9939609 polymorphism and obesity. It is also in agreement with studies on Mexican, Spanish and European populations, where an association was found with obesity class III.

Conclusion: The rs9939609 polymorphism of FTO gene is associated with obesity, especially obesity class III in women.     

Two mitochondrial haplotypes in Pterochloroides persicae (Hemiptera: Aphididae: Lachninae) associated with different feeding sites

Pterochloroides persicae (Cholodkovsky) is an aphid species belonging to the subfamily Lachninae that uses different members of Rosaceae (specially Prunus spp.) as hosts. Partial sequences from the mitochondrial cytochrome c oxidase 1 (COI) and the nuclear long‐wave opsin genes were obtained for approximately 100 P. persicae aphid individuals sampled from 34 colonies collected mainly in Tunisia and other Mediterranean locations. The variability found at the mitochondrial locus revealed the presence of two maternal haplotypes in the studied area that differed in a single nucleotide. The nuclear gene analyzed, however, failed to reveal any variability in this species. The variability found at the COI locus was related to the season of aphid sampling and with the site of feeding, with haplotype I mostly detected in samples collected in spring and summer on trunks and branches and haplotype II only detected in aphids collected in autumn on roots. The observed pattern of molecular variation suggests the presence of two clonal races of P. persicae coexisting in the studied area differentially adapted to conditions prevalent in the alternative seasons and/or to different feeding sites.     

The cytosolic glutamine synthetase GLN1;2 plays a role in the control of plant growth and ammonium homeostasis in Arabidopsis rosettes when nitrate supply is not limiting

Glutamine synthetase (EC 6.3.1.2) is a key enzyme of ammonium assimilation and recycling in plants where it catalyses the synthesis of glutamine from ammonium and glutamate. In Arabidopsis, five GLN1 genes encode GS1 isoforms. GLN1;2 is the most highly expressed in leaves and is over-expressed in roots by ammonium supply and in rosettes by ample nitrate supply compared with limiting nitrate supply. It is shown here that the GLN1;2 promoter is mainly active in the minor veins of leaves and flowers and, to a lower extent, in the parenchyma of mature leaves. Cytoimmunochemistry reveals that the GLN1;2 protein is present in the companion cells. The role of GLN1;2 was determined by examining the physiology of gln1;2 knockout mutants. Mutants displayed lower glutamine synthetase activity, higher ammonium concentration, and reduced rosette biomass compared with the wild type (WT) under ample nitrate supply only. No difference between mutant and WT can be detected under limiting nitrate conditions. Despite total amino acid concentration was increased in the old leaves of mutants at high nitrate, no significant difference in nitrogen remobilization can be detected using (15)N tracing. Growing plants in vitro with ammonium or nitrate as the sole nitrogen source allowed us to confirm that GLN1;2 is induced by ammonium in roots and to observe that gln1;2 mutants displayed, under such conditions, longer root hair and smaller rosette phenotypes in ammonium. Altogether the results suggest that GLN1;2 is essential for nitrogen assimilation under ample nitrate supply and for ammonium detoxification.     

Neu-Laxova Syndrome,an Inborn Error of Serine Metabolism,Is Caused by Mutations in PHGDH

Neu-Laxova syndrome (NLS) is a rare autosomal-recessive disorder characterized by severe fetal growth restriction, microcephaly, a distinct facial appearance, ichthyosis, skeletal anomalies, and perinatal lethality. The pathogenesis of NLS remains unclear despite extensive clinical and pathological phenotyping of the >70 affected individuals reported to date, emphasizing the need to identify the underlying genetic etiology, which remains unknown. In order to identify the cause of NLS, we conducted a positional-mapping study combining autozygosity mapping and whole-exome sequencing in three consanguineous families affected by NLS. Surprisingly, the NLS-associated locus identified in this study was solved at the gene level to reveal mutations in PHGDH, which is known to be mutated in individuals with microcephaly and developmental delay. PHGDH encodes the first enzyme in the phosphorylated pathway of de novo serine synthesis, and complete deficiency of its mouse ortholog recapitulates many of the key features of NLS. This study shows that NLS represents the extreme end of a known inborn error of serine metabolism and highlights the power of genomic sequencing in revealing the unsuspected allelic nature of apparently distinct clinical entities.     

Anti-microfouling properties of compounds isolated from several Mediterranean Dictyota spp.

Brown algae of the genus Dictyota are widespread around the world and are common along the coasts of the Mediterranean Sea. These marine organisms keep their surface relatively free from biofouling and are known for their ability to produce a wide array of bioactive compounds, mostly diterpenes, whose ecological functions are not clearly defined. In this study, an evaluation of the chemodiversity of the Dictyota genus was conducted on three samples, harvested on both NW and SW Mediterranean coasts (France and Algeria, respectively). Ten compounds were purified from the organic extracts of these samples; their chemical structures were elucidated by 1D and 2D NMR spectroscopy and were compared with literature data. Among them, three new diterpenes [one dolabellane (1), one xenicane (2), and one prenylated guaiane (3)] were characterized together with five previously described compounds [3,4-epoxy-14-oxo-7,18-dolabelladiene (4), acetoxycrenulide (5), dictyol E (6), 10,18-dihydroxydolabella-2,7-diene (7), and 10-acetoxy-18-hydroxydolabella-2,7-diene (8)]. In addition, the occurrence of two known glycerol derivatives [1-Ο-octadecenoylglycerol (9) and sn-3-Ο-(geranylgeranyl)glycerol (10)] was also determined. Some of the isolated compounds (4–6 and 8–10) were screened for their potential to prevent the adhesion of three bacterial strains isolated from marine biofilms in comparison with four commercial antifoulants (TBTO, Zineb, ZnPT, and CuPT): those bearing a glycerol moiety (compounds 9 and 10) exhibited the strongest anti-adhesion effects, whatever the strain, and with a moderate toxicity. Thus, these chemical structures should be further explored for both their putative involvement in keeping the algal surface free of biofouling and the development of effective and environmentally benign antifoulants.     

Macrophage Migration Inhibitory Factor Is Involved in Ectopic Endometrial Tissue Growth and Peritoneal-Endometrial Tissue Interaction In Vivo: A Plausible Link to Endometriosis Development

Pelvic inflammation is a hallmark of endometriosis pathogenesis and a major cause of the disease''s symptoms. Abnormal immune and inflammatory changes may not only contribute to endometriosis-major symptoms, but also contribute to ectopic endometrial tissue growth and endometriosis development. A major pro-inflammatory factors found elevated in peritoneal fluid of women with endometriosis and to be overexpressed in peritoneal fluid macrophages and active, highly vascularized and early stage endometriotic lesions, macrophage migration inhibitory factor (MIF) appeared to induce angiogenic and inflammatory and estrogen producing phenotypes in endometriotic cells in vitro and to be a possible therapeutic target in vivo. Using a mouse model where MIF-knock out (KO) mice received intra-peritoneal injection of endometrial tissue from MIF-KO or syngeneic wild type (WT) mice and vice versa, our current study revealed that MIF genetic depletion resulted in a marked reduction ectopic endometrial tissue growth, a disrupted tissue structure and a significant down regulation of the expression of major inflammatory (cyclooxygenease-2), cell adhesion (αv and β3 integrins), survival (B-cell lymphoma-2) and angiogenic (vascular endothelial cell growth) factorsrelevant to endometriosis pathogenesis, whereas MIF add-back to MIF-KO mice significantly restored endometriosis-like lesions number and size. Interestingly, cross-experiments revealed that MIF presence in both endometrial and peritoneal host tissues is required for ectopic endometrial tissue growth and pointed to its involvement in endometrial-peritoneal interactions. This study provides compelling evidence for the role of MIF in endometriosis development and its possible interest for a targeted treatment of endometriosis.     

Morphometry and biological parameters of different instars of the giant brown peach aphid: Pterochloroides persicae Cholodkovsky 1899 (Hemiptera: Aphididae) in Tunisia

Summary. Individuals of Pterochloroides persicae reared under controlled conditions were used to describe the morphometry and biological parameters of instars of this aphid. Our results showed that P. persicae developed four instars before reaching the adult stage. The first and the second larval instars both have five antennal segments, although the others have six segments. A significant difference was observed between instars in the first antennal segment (F = 56.11; df = 4, P = 0.026), in the body length (F = 115.38; df = 4, p = 0.014) and in the cauda length (F = 72, 77; df = 4, p = 0.021). The study of developmental and reproductive performance of P. persicae showed that the first instar lasted for 3.17 days, the second instar 2.35 days, the third instar 4.68 days, the fourth instar 5.035 days and the adult 6.86 days. We demonstrate also that the generation time lasted for 15.26 days. The life span was 22.11 days. As for fecundity, a single female of P. persicae gave birth to 29.68 ± 7.38 nymphs with an average reproductive rate per day of 4.32 ± 2.16.     

Identification of glioma neovascularization-related proteins by using MALDI-FTMS and nano-LC fractionation to microdissected tumor vessels

The identification of angiogenesis-related proteins is important for the development of new antiangiogenic therapies, and such proteins are potential new biomarkers for gliomas. The aim of this study was to identify proteins that are exclusively present in glioma neovasculature and not in the vasculature of normal brain. We combined advanced proteomics techniques to compare the expression profiles of microdissected blood vessels from glioma with blood vessels of normal control brain samples. We measured the enzymatic generated peptide profiles from these microdissected samples by MALDI-FTMS. Subsequently, the samples were fractionated by nano-LC prior to MALDI-TOF/TOF. This combined approach enabled us to identify four proteins that appeared to be exclusively expressed in the glioma blood vessels. Two of these proteins, fibronectin and colligin 2, were validated on tissue sections using specific antibodies. We found that both proteins are present in active angiogenesis in glioma, other neoplasms, and reactive conditions in which neoangiogenesis takes place. This work proves that gel-free mass spectrometric techniques can be used on relatively small numbers of cells generated by microdissection procedures to successfully identify differentially expressed proteins.