BBS10 encodes a vertebrate-specific chaperonin-like protein and is a major BBS locus

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous ciliopathy. Although nine BBS genes have been cloned, they explain only 40-50% of the total mutational load. Here we report a major new BBS locus, BBS10, that encodes a previously unknown, rapidly evolving vertebrate-specific chaperonin-like protein. We found BBS10 to be mutated in about 20% of an unselected cohort of families of various ethnic origins, including some families with mutations in other BBS genes, consistent with oligogenic inheritance. In zebrafish, mild suppression of bbs10 exacerbated the phenotypes of other bbs morphants.     

Pineal indols and testosterone affect exploratory activity of male rats

Summary The testosterone level has an inverse relation to activity in the open-field test. This is more important in red light than in white light. Pineal indols do not disturb this action. Some of these results are consistent with the assumption that androgens play a role on the exploratory activity of adult subjects.     

Evolutionary change from induced to constitutive expression of an indirect plant resistance

Induced plant resistance traits are expressed in response to attack and occur throughout the plant kingdom. Despite their general occurrence, the evolution of such resistances has rarely been investigated. Here we report that extrafloral nectar, a usually inducible trait, is constitutively secreted by Central American Acacia species that are obligately inhabited by ants. Extrafloral nectar is secreted as an indirect resistance, attracting ants that defend plants against herbivores. Leaf damage induces extrafloral nectar secretion in several plant species; among these are various Acacia species and other Fabaceae investigated here. In contrast, Acacia species obligately inhabited by symbiotic ants nourish these ants by secreting extrafloral nectar constitutively at high rates that are not affected by leaf damage. The phylogeny of the genus Acacia and closely related genera indicate that the inducibility of extrafloral nectar is the plesiomorphic or 'original' state, whereas the constitutive extrafloral nectar flow is derived within Acacia. A constitutive resistance trait has evolved from an inducible one, obviously in response to particular functional demands.     

A transmembrane protein required for acetylcholine receptor clustering in Caenorhabditis elegans

Clustering neurotransmitter receptors at the synapse is crucial for efficient neurotransmission. Here we identify a Caenorhabditis elegans locus, lev-10, required for postsynaptic aggregation of ionotropic acetylcholine receptors (AChRs). lev-10 mutants were identified on the basis of weak resistance to the anthelminthic drug levamisole, a nematode-specific cholinergic agonist that activates AChRs present at neuromuscular junctions (NMJs) resulting in muscle hypercontraction and death at high concentrations. In lev-10 mutants, the density of levamisole-sensitive AChRs at NMJs is markedly reduced, yet the number of functional AChRs present at the muscle cell surface remains unchanged. LEV-10 is a transmembrane protein localized to cholinergic NMJs and required in body-wall muscles for AChR clustering. We also show that the LEV-10 extracellular region, containing five predicted CUB domains and one LDLa domain, is sufficient to rescue AChR aggregation in lev-10 mutants. This suggests a mechanism for AChR clustering that relies on extracellular protein-protein interactions. Such a mechanism is likely to be evolutionarily conserved because CUB/LDL transmembrane proteins similar to LEV-10, but lacking any assigned function, are expressed in the mammalian nervous system and might be used to cluster ionotropic receptors in vertebrates.     

Effects of constant light exposure and blindness on the oxidative metabolism of selected brain areas in male rats

Summary Male rats were housed in continous illumination or blinded when 21 day-old and killed 69 days later. The continuous illumination exposure increased the weights of testes and sex accessory organs and reduced the pineal gland weight. Blindness decreased weights of testes, sex accessory organs and anterior pituitary. The oxygen consumption rate of the hypothalamus was higher in the blinded animals than in the controls and lower in the continuously illuminated rats. No one of such groups showed significant changes in the oxygen consumption by either the amygdata or the hippocampus.