The chemokine BRAK/CXCL14 regulates synaptic transmission in the adult mouse dentate gyrus stem cell niche

The chemokine BRAK/CXCL14 is an ancient member of the chemokine family whose functions in the brain are completely unknown. We examined the distribution of CXCL14 in the nervous system during development and in the adult. Generally speaking, CXCL14 was not expressed in the nervous system prior to birth, but it was expressed in the developing whisker follicles (E14.5) and subsequently in the hair follicles and skin. Postnatally, CXCL14 was also highly expressed in many regions of the brain, including the cortex, basal ganglia, septum and hippocampus. CXCL14 was also highly expressed in the dorsal root ganglia. We observed that in the hippocampal dentate gyrus (DG) CXCL14 was expressed by GABAergic interneurons. We demonstrated that CXCL14 inhibited GABAergic transmission to nestin-EGFP-expressing neural stem/progenitor cells in the adult DG. CXCL14 inhibited both the tonic and phasic effects of synaptically released GABA. In contrast CXCL12 enhanced the effects of GABA at these same synapses. CXCL14 increased [Ca(2+)](i) in neural stem cells cultured from the postnatal brain indicating that they expressed the CXCL14 receptor. These observations are consistent with the view that CXCL12 and CXCL14 may normally act as positive and negative regulators of the effects of GABA in the adult DG stem cell niche.     

The Black-necked Grebe (Podiceps nigricollis): an expanding species in the Middle Atlas wetlands,Morocco

The present study investigates the population trends of Black-necked Grebe Podiceps nigricollis (Podicipedidae: Podicidae) over 5 years (2009–2013) in three Middle Atlas wetlands (Aguelmam Afennourir, Dayet Aoua and Dayet Ifrah). Using generalized linear models with a Poisson distribution, we demonstrated that the number of Black-necked Grebe breeding pairs has varied significantly and positively over the 5 years and between the three study wetlands. The annual population growth rate of the three colonies was 0.48 (±0.01). This positive trend is consistent with the current Least Concern conservation status of the IUCN Red List. Further more detailed studies are, however, needed to improve our understanding on the mechanisms driving the population increase in this part of North Africa. This remains a prerequisite for proper population conservation and management.     

Founder mutations in Tunisia: implications for diagnosis in North Africa and Middle East

ABSTRACT: Background Tunisia is a North African country of 10 million inhabitants. The native background population is Berber. However, throughout its history, Tunisia has been the site of invasions and migratory waves of allogenic populations and ethnic groups such as Phoenicians, Romans, Vandals, Arabs, Ottomans and French. Like neighbouring and Middle Eastern countries, the Tunisian population shows a relatively high rate of consanguinity and endogamy that favor expression of recessive genetic disorders at relatively high rates. Many factors could contribute to the recurrence of monogenic morbid trait expression. Among them, founder mutations that arise in one ancestral individual and diffuse through generations in isolated communities. Method We report here on founder mutations in the Tunisian population by a systematic review of all available data from PubMed, other sources of the scientific literature as well as unpublished data from our research laboratory. Results We identified two different classes of founder mutations. The first includes founder mutations so far reported only among Tunisians that are responsible for 30 genetic diseases. The second group represents founder haplotypes described in 51 inherited conditions that occur among Tunisians and are also shared with other North African and Middle Eastern countries. Several heavily disabilitating diseases are caused by recessive founder mutations. They include, among others, neuromuscular diseases such as congenital muscular dystrophy and spastic paraglegia and also severe genodermatoses such as dystrophic epidermolysis bullosa and xeroderma pigmentosa. Conclusion This report provides informations on founder mutations for 73 genetic diseases either specific to Tunisians or shared by other populations. Taking into account the relatively high number and frequency of genetic diseases in the region and the limited resources, screening for these founder mutations should provide a rapid and cost effective tool for molecular diagnosis. Indeed, our report should help designing appropriate measures for carrier screening, better evaluation of diseases burden and setting up of preventive measures at the regional level.     

Concurrent Bilateral Renal Angiomyolipoma and Renal Cell Carcinoma in a Patient With Tuberous Sclerosis Complex

Renal angiomyolipomas (AMLs) are often associated with tuberous sclerosis. These tumors are predominantly benign, although malignant forms do exist and are known to be associated with renal cell carcinoma. This case report describes a patient with tuberous sclerosis and massive bilateral AML. Total right nephrectomy was performed; histopathologic examination revealed the coexistence of AML and clear cell renal carcinoma in the same kidney. Because differentiation between renal cell carcinoma and AML with minimal or no fat component can be difficult, an accurate diagnosis is critical in the management of renal AML.Key words: Angiomyolipoma, Renal cell carcinoma, Tuberous sclerosisApproximately 80% of patients with tuberous sclerosis complex (TSC) develop renal angiomyolipoma (AML). Although often benign,^1,2 malignant AML and renal cell carcinoma (RCC) have also been reported in patients with TSC. The concurrence of renal AML and RCC in the same kidney has also been reported in patients with TSC and has been revealed on pathologic examination.Several criteria can be used to help predict malignancy in renal AML, such as tumor size, tumor size and necrosis, and atypical mitotic figures. We report a case of associated massive bilateral AML and RCC. We discuss the diagnosis and treatment of renal AML and emphasize the possibility of concurrent renal malignancies in patients with TSC.     

Linkage analysis in spinal muscular atrophy, by six closely flanking markers on chromosome 5

The proximal spinal muscular atrophies (SMA) represent the second most common autosomal recessive disorder, after cystic fibrosis. The gene responsible for chronic SMA has recently been mapped to chromosome 5q by using genetic linkage studies. Among six markers mapping to this region, five were shown to be linked with the SMA locus in 39 chronic SMA families each containing at least two affected individuals. Multilocus analysis by the method of location score was used to establish the best estimate of the SMA gene location. Our data suggest that the most likely location for SMA is between loci D5S6 and D5S39. The genetic distances between these two markers are estimated to be 6.4 cM in males and 11.9 cM in females. Since meiosis were informative with D5S39 and D5S6 in 92% and 87% of SMA families, respectively, it is hoped that the present study will contribute to the calculation of genetic risk in SMA families.     

Involvement of polyamines in the interacting effects of low temperature and mineral supply on Pringlea antiscorbutica (Kerguelen cabbage) seedlings

Pringlea antiscorbutica, which is the sole endemic crucifer in the subantarctic zone, undergoes seedling development in a harsh and cold environment. Since, at the mature stage, this species exhibits several adaptations linked to cold tolerance such as high polyamine levels, potential adaptations and polyamine response were investigated in seedlings. In order to assess the specificity of responses, P. antiscorbutica was compared with Arabidopsis thaliana, which is characterized by a life cycle preventing cold exposure at seedling stage. P. antiscorbutica and A. thaliana seedlings were found to have strikingly contrasted responses to temperature changes and to mineral nutrition. Whereas A. thaliana seedlings showed the typical growth arrest of chilling-sensitive plants, P. antiscorbutica seedlings showed optimal root growth at low temperature (5/10 degrees C) and temperate conditions caused the early arrest of root growth. Cold tolerance was associated with increased levels of polyamines or with maintenance of high levels of polyamines. Comparison of both species showed that polyamine levels could be a significant marker of chilling tolerance in seedlings. Treatments with varying mineral supply showed a positive relationship between root growth rate and variations of agmatine and putrescine endogenous contents in roots of P. antiscorbutica. This may be the first demonstration that, even under conditions of accumulation induced by environmental stress, polyamine levels can still be correlated with developmental processes. Com parison of mineral supply and temperature effects strongly indicated a trade-off of polyamine involvement between development and response to stress.     

Biotinidase deficiency: Novel mutations in Algerian patients

Biotinidase deficiency is an autosomal recessive disorder of biotin metabolism leading to varying degrees of neurologic and cutaneous symptoms when untreated. In the present study, we report the clinical features and the molecular investigation of biotinidase deficiency in four unrelated consanguineous Algerian families including five patients with profound biotinidase deficiency and one child characterized as partial biotinidase deficiency. Mutation analysis revealed three novel mutations, c.del631C and c.1557T>G within exon 4 and c.324-325insTA in exon 3. Since newborn screening is not available in Algeria, cascade screening in affected families would be very helpful to identify at risk individuals.     

Sugar-induced tolerance to the herbicide atrazine in Arabidopsis seedlings involves activation of oxidative and xenobiotic stress responses

Exogenous sucrose confers to Arabidopsis seedlings a very high level of tolerance to the herbicide atrazine that cannot be ascribed to photoheterotrophic growth. Important differences of atrazine tolerance between sucrose and glucose treatments showed that activation of chloroplast biogenesis per se could not account for induced tolerance. Sucrose-induced acquisition of defence mechanisms was shown by the gene expression pattern of a chloroplastic iron superoxide dismutase and by enhancement of whole-cell glucose-6-phosphate dehydrogenase activity. Activation of these defence mechanisms depended on both soluble sugar and atrazine. Moreover, acquisition of sucrose protection was shown to unmask atrazine-induced gene expression, such as that of a cytosolic glutathione-S-transferase, which remained otherwise cryptic because of the lethal effects of atrazine in the absence of soluble sugars.     

Domain organization within repeated DNA sequences: application to the study of a family of transposable elements

MOTIVATION: The analysis of repeated elements in genomes is a fascinating domain of research that is lacking relevant tools for transposable elements (TEs), the most complex ones. The dynamics of TEs, which provides the main mechanism of mutation in some genomes, is an essential component of genome evolution. In this study we introduce a new concept of domain, a segmentation unit useful for describing the architecture of different copies of TEs. Our method extracts occurrences of a terminus-defined family of TEs, aligns the sequences, finds the domains in the alignment and searches the distribution of each domain in sequences. After a classification step relative to the presence or the absence of domains, the method results in a graphical view of sequences segmented into domains. RESULTS: Analysis of the new non-autonomous TE AtREP21 in the model plant Arabidopsis thaliana reveals copies of very different sizes and various combinations of domains which show the potential of our method. AVAILABILITY: DomainOrganizer web page is available at www.irisa.fr/symbiose/DomainOrganizer/.