Abnormal cerebellar development and axonal decussation due to mutations in AHI1 in Joubert syndrome

Joubert syndrome is a congenital brain malformation of the cerebellar vermis and brainstem with abnormalities of axonal decussation (crossing in the brain) affecting the corticospinal tract and superior cerebellar peduncles. Individuals with Joubert syndrome have motor and behavioral abnormalities, including an inability to walk due to severe clumsiness and 'mirror' movements, and cognitive and behavioral disturbances. Here we identified a locus associated with Joubert syndrome, JBTS3, on chromosome 6q23.2-q23.3 and found three deleterious mutations in AHI1, the first gene to be associated with Joubert syndrome. AHI1 is most highly expressed in brain, particularly in neurons that give rise to the crossing axons of the corticospinal tract and superior cerebellar peduncles. Comparative genetic analysis of AHI1 indicates that it has undergone positive evolutionary selection along the human lineage. Therefore, changes in AHI1 may have been important in the evolution of human-specific motor behaviors.     

COURSE TIMETABLING AT A TUNISIAN UNIVERSITY： A CASE STUDY

This paper deals with the Course Timetabling Problem at an institution in a Tunisian University. We introduce a heuristic procedure to construct a feasible timetable for all lectures and tutorials taken by different groups of each sub-section of any section. We describe the timetabling problem using a list of all specific hard and soft constraints. We formulate the problem as a set of linear constraints using two sets of binary variables corresponding to lectures and tutorials, respectively. This heuristic is illustrated with real data for a sub-section of the Faculty of Economics and Management Sciences of Sfax in Tunisia, and the resulting timetables are compared with those generated manually. The results of another full section have confirmed the good quality of the proposed heuristic when compared with the hand made solution.     

Inhibitory effects of LHRH on LH receptors in the rat testis]

A single injection of LHRH to the adult male rat, as of its analog [D-Ala6, des-Gly-NH102] LHRH ethylamide, resulted in a marked decrease in LH receptors in the tests. Plasma testosterone level and the weight of the seminal vesicles and prostate were also decreased after treatment. These data demonstrate that LHRH can decrease the sensitivity of LH receptors and testicular function in the rat.     

Primary cilia proteins: ciliary and extraciliary sites and functions

Primary cilia are immotile organelles known for their roles in development and cell signaling. Defects in primary cilia result in a range of disorders named ciliopathies. Because this organelle can be found singularly on almost all cell types, its importance extends to most organ systems. As such, elucidating the importance of the primary cilium has attracted researchers from all biological disciplines. As the primary cilia field expands, caution is warranted in attributing biological defects solely to the function of this organelle, since many of these “ciliary” proteins are found at other sites in cells and likely have non-ciliary functions. Indeed, many, if not all, cilia proteins have locations and functions outside the primary cilium. Extraciliary functions are known to include cell cycle regulation, cytoskeletal regulation, and trafficking. Cilia proteins have been observed in the nucleus, at the Golgi apparatus, and even in immune synapses of T cells (interestingly, a non-ciliated cell). Given the abundance of extraciliary sites and functions, it can be difficult to definitively attribute an observed phenotype solely to defective cilia rather than to some defective extraciliary function or a combination of both. Thus, extraciliary sites and functions of cilia proteins need to be considered, as well as experimentally determined. Through such consideration, we will understand the true role of the primary cilium in disease as compared to other cellular processes’ influences in mediating disease (or through a combination of both). Here, we review a compilation of known extraciliary sites and functions of “cilia” proteins as a means to demonstrate the potential non-ciliary roles for these proteins.     

Inhibitory effects of LHRH on ovarian LH receptors in rats]

The administration of LHRH or of its analog [D-Ala6, des-Gly-NH10(2)] LHRH ethylamide to the female rat on day 10 of gestation resulted in termination of pregnancy and in a marked decrease in ovarian LH receptors and plasma progesterone level. Asingle injection of either compound during diestrus I also led to a decrease in LH receptors. These data demonstrate the high sensitivity of the control of ovarian LH receptors by circulating gonadotrophins and suggest that the contraceptive action of pre- and postcoitally administered LHRH is mediated by negative control of LH receptors.