Calx, a Na-Ca exchanger gene of Drosophila melanogaster

We have cloned Calx, a gene that encodes a Na-Ca exchanger of Drosophila melanogaster. Calx encodes two repeated motifs, Calx-α and Calx-β, that overlap domains required for exchanger activity and regulation. Calx has multiple transcripts in adults, including at least one expressed in the retina. The Calx genomic locus comprises ≥35 kb between the Atpα and rudimentary-like genes in chromosomal region 93B. In Xenopus oocytes, microinjected Calx cRNA induces calcium uptake like that of its homolog, the 3Na^+-1Ca^(2+) exchanger of mammalian heart. Implications of Calx-α motifs for the mechanism of Na-Ca exchange are discussed

Breeding properties of Tinca tinca (L., 1758) living in Kapulukaya Reservoir (Kirikkale, Turkey)

This study involves the investigation of Tinca tinca (L., 1758) living in Kapulukaya Reservoir in Turkey. It was observed that the fish reach sexual maturity at the age of III and the breeding period starts in May and ends in July. The mean monthly gonadosomatic indices varied from 1.38 ±0.06 (in October) to 8.01±1.03 (in May). According to monthly variations of the GSI, spawning of the tench takes place between May (8.01 ± 1.03) and June (5.50 ± 0.57). The average egg number per fish was estimated to be 23403 ± 17047 . The eggs diameters varied from 0.50 mm to 1.33 mm (mean 0.86 mm). The relations between the fecundity (F) and body length (L) and body weight (W) were found as F = 0.037799 × L 1.0212 (r = 0.70) and F = 0. 00000175 × W 2.8696 (r = 0.62)

Short communication: Growth properties of tench (Tinca tinca L., 1758) living in Hirfanlı Reservoir (Kırşehir, Turkey)

Tinca tinca is originally from the Near East and West-Siberia and nowadays is spread all over the world. Previous reports showed that they abundantly present in the rivers flowing to the Black Sea and various lakes as well as in rivers in Central Anatolia. It has no economical importance due to its slow growth rate and tasteless meat. There are many publications on the growth and the bio-ecology and feeding of T. tinca. This study was carried out to investigate the growth properties, such as weight, length and condition factor, in T. tinca inhabit in Hirfanlı Reservoir built in 1959 on Kızılırmak River with the altitude of 856m and volume of 7.63 x10^9m^3. The study was carried out from August 1996 to July 1997 on 241 T. tinca species

Regulation of Lifespan in Drosophila by Modulation of Genes in the TOR Signaling Pathway

In many species, reducing nutrient intake without causing malnutrition extends lifespan 1, 2, 3. Like DR (dietary restriction), modulation of genes in the insulin-signaling pathway, known to alter nutrient sensing, has been shown to extend lifespan in various species 1, 2, 3, 4. In Drosophila, the target of rapamycin (TOR) and the insulin pathways have emerged as major regulators of growth and size. Hence we examined the role of TOR pathway genes in regulating lifespan by using Drosophila. We show that inhibition of TOR signaling pathway by alteration of the expression of genes in this nutrient-sensing pathway, which is conserved from yeast to human, extends lifespan in a manner that may overlap with known effects of dietary restriction on longevity. In Drosophila, TSC1 and TSC2 (tuberous sclerosis complex genes 1 and 2) act together to inhibit TOR (target of rapamycin), which mediates a signaling pathway that couples amino acid availability to S6 kinase, translation initiation, and growth [5]. We find that overexpression of dTsc1, dTsc2, or dominant-negative forms of dTOR or dS6K all cause lifespan extension. Modulation of expression in the fat is sufficient for the lifespan-extension effects. The lifespan extensions are dependent on nutritional condition, suggesting a possible link between the TOR pathway and dietary restriction

Minimal Obstructions for Partial Representations of Interval Graphs

Interval graphs are intersection graphs of closed intervals. A generalization of recognition called partial representation extension was introduced recently. The input gives an interval graph with a partial representation specifying some pre-drawn intervals. We ask whether the remaining intervals can be added to create an extending representation. Two linear-time algorithms are known for solving this problem. In this paper, we characterize the minimal obstructions which make partial representations non-extendible. This generalizes Lekkerkerker and Boland's characterization of the minimal forbidden induced subgraphs of interval graphs. Each minimal obstruction consists of a forbidden induced subgraph together with at most four pre-drawn intervals. A Helly-type result follows: A partial representation is extendible if and only if every quadruple of pre-drawn intervals is extendible by itself. Our characterization leads to a linear-time certifying algorithm for partial representation extension

4E-BP Extends Lifespan upon Dietary Restriction by Enhancing Mitochondrial Activity in Drosophila

Dietary restriction (DR) extends lifespan in multiple species. To examine the mechanisms of lifespan extension upon DR, we assayed genome-wide translational changes in Drosophila. A number of nuclear encoded mitochondrial genes, including those in Complex I and IV of the electron transport chain, showed increased ribosomal loading and enhanced overall activity upon DR. We found that various mitochondrial genes possessed shorter and less structured 5′UTRs, which were important for their enhanced mRNA translation. The translational repressor 4E-BP, the eukaryotic translation initiation factor 4E binding protein, was upregulated upon DR and mediated DR dependent changes in mitochondrial activity and lifespan extension. Inhibition of individual mitochondrial subunits from Complex I and IV diminished the lifespan extension obtained upon DR, reflecting the importance of enhanced mitochondrial function during DR. Our results imply that translational regulation of nuclear-encoded mitochondrial gene expression by 4E-BP plays an important role in lifespan extension upon DR