Genetic Dissection of the Contribution of Central and Peripheral Circadian Clocks to Drosophila Feeding Rhythms

The circadian system produces ~24-hr rhythms and consists of three major components: a central molecular clock in the brain that keeps time, input pathways that allow organisms to stay synchronized with changes in their environment, and output pathways that couple the clock to various behavioral and physiological processes such as locomotion. Recent studies have demonstrated circadian control of feeding independent of locomotor activity, but the neuronal circuitry governing feeding rhythms is not understood. In addition to the central brain clock, circadian clocks are present in many peripheral tissues, such as the Drosophila melanogaster fat body, which is homologous to the mammalian liver and regulates metabolism. Here, we investigated the feeding behavior of transgenic flies in which we eliminated or changed the speed of the brain or fat body clock to identify the contributions of central and peripheral circadian clocks to feeding rhythms. We additionally conducted immunohistochemical analysis to confirm molecular clock speed alterations in these flies

Physical properties of seven binary and higher-order multiple OB systems

Analyses of multi-epoch, high-resolution (~ 50000) optical spectra of seven early-type systems provided various important new insights with respect to their multiplicity. First determinations of orbital periods were made for HD 92206C (2.022 d), HD 112244 (27.665 d), HD 164438 (10.25 d), HD 123056A (~ 1314 d) and HD 123056B (< 2 d); the orbital period of HD 318015 could be improved (23.445975 d). Concerning multiplicity, a third component was discovered for HD 92206C by means of He I line profiles. For HD 93146A, which was hitherto assumed to be SB1, lines of a secondary component could be discerned. HD 123056 turns out to be a multiple system consisting of a high-mass component A (~ O8.5) displaying a broad He II 5411 A feature with variable radial velocity, and of an inner pair B (~ B0) with double He I lines. The binary HD 164816 was revisited and some of its system parameters were improved. In particular, we determined its systemic velocity to be -7 km/s, which coincides with the radial velocity of the cluster NGC 6530. This fact, together with its distance, suggests the cluster membership of HD 164816. The OB system HD 318015 (V1082 Sco) belongs to the rare class of eclipsing binaries with a supergiant primary (B0.5/0.7). Our combined orbital and light-curve analysis suggests that the secondary resembles an O9.5III star. Our results for a limited sample corroborate the findings that many O stars are actually massive multiple systems.Comment: 16 pages, 16 figures, to appear in Astronomy and Astrophysic

Subcloning of Flag-STN1-Flag from pBabe-puro to pCL-Flag-myc-puro to Test Relationship Between STN1 and Chemotherapeutic Agents

STN1 is a subunit of the CTC1-STN1-TEN1 (CST) protein complex. The CST complex is a highly conserved single-stranded DNA binding protein, that plays an important role in telomerase maintenance and promoting DNA replication under replication stress. Telomeres are regions at the end of the chromosomes that protect our DNA and maintain genome stability. Genome instability is one of the main causes of cancer and aging-related diseases. The activity of the STN1 component of the CST complex has been tied to rescuing genome stability under conditions of replication stress, and STN1 dysfunction has been associated with cancer and apoptosis. Therefore, further understanding of STN1 function is essential for studying cancer and chemotherapeutic agents. In this study, we cloned the STN1 gene and created a flag tag for STN1 to provide a tool for performing transient transfection and identifying STN1’s interacting partners. We successfully amplified STN1 with PCR, digested purified STN1 and pCL-Flag-myc-puro cloning vector with restriction enzymes, ligated the two DNAs, transformed competent Escherichia coli bacteria, and screened the plasmid for insertion. Our results from the PCR, restriction enzyme mapping, and DNA sequencing verified that we successfully cloned the gene, flag-STN1-flag, into a pCL-flag-myc-puro vector from pBabe-puro

Multiplicity of high-mass stars

Die vorliegende Arbeit hat die Multiplizität von O Sternen anhand von hochaufgelösten optischen Spektren untersucht. Der erste Teil der Arbeit beschreibt die statistischen Ergebnisse einer Stichprobe von 249 südlichen O Sternen. 63% der Spektren zeigen klare Hinweise auf Multiplizität, wobei es 46% SB2 und 17% SB1 Typen gibt. Betrachtet man nur Sterne heller als V = 8 mag so erhöht sich der Doppelsternanteil auf 79%. Der große Anteil von SB2 System spricht dafür, dass viele O-Sterne als masseähnliche Zwillinge entstehen. Der zweite Teil der Arbeit beschäftigt sich mit dem O9 IV Stern HD152246. Die Analyse von 49 Spektren hat gezeigt, dass es sich um ein hierarchisches Dreifachsystem handelt, bei dem sich ein inneres Paar mit einem leicht exzentrischen Orbit (e = 0.11) und einer Periode von 6 Tagen mit einem weiteren O9 Stern in 470 Tagen auf einem extrem exzentrischen Orbit (e=0.865) um den gemeinsamen Schwerpunkt bewegt

GENETIC DISSECTION OF THE CONTRIBUTION OF CENTRAL AND PERIPHERAL CIRCADIAN CLOCKS TO DROSOPHILA FEEDING RHYTHMS

The endogenous circadian clock of biological organisms is what allows them to synchronize their behavioral and physiological circadian rhythms to their environment. This circadian rhythm regulates the timing of behaviors like sleeping, eating, locomotion, etc. The circadian circuit operates by input pathways, a central clock in the brain, and output pathways. This circuitry depends on the oscillation of core clock genes, present in both the brain and in peripheral tissues. Although much is known about the central clock on the molecular level, not much is known about the molecular mechanisms of peripheral clocks, and how they interact with the central clock to produce rhythmic behaviors. In our experiments, we investigated the role of the fat body clock’s contribution to feeding rhythms in Drosophila melanogaster. Here, we demonstrate that genetically speeding up, slowing down, or completely eliminating the central clock alters feeding behavior. Conversely, genetic manipulation of the fat body clock did not alter feeding behavior. These findings indicate that the central clock in the brain functions as the master regulator of feeding rhythms. Key words: circadian, central clock, fat body clock, peripheral clock, feeding rhythm

Clinical Characteristics and Outcomes of Colorectal Cancer in the ColoCare Study: Differences by Age of Onset.

Early-onset colorectal cancer has been on the rise in Western populations. Here, we compare patient characteristics between those with early- (&lt;50 years) vs. late-onset (≥50 years) disease in a large multinational cohort of colorectal cancer patients (n = 2193). We calculated descriptive statistics and assessed associations of clinicodemographic factors with age of onset using mutually-adjusted logistic regression models. Patients were on average 60 years old, with BMI of 29 kg/m2, 52% colon cancers, 21% early-onset, and presented with stage II or III (60%) disease. Early-onset patients presented with more advanced disease (stages III-IV: 63% vs. 51%, respectively), and received more neo and adjuvant treatment compared to late-onset patients, after controlling for stage (odds ratio (OR) (95% confidence interval (CI)) = 2.30 (1.82-3.83) and 2.00 (1.43-2.81), respectively). Early-onset rectal cancer patients across all stages more commonly received neoadjuvant treatment, even when not indicated as the standard of care, e.g., during stage I disease. The odds of early-onset disease were higher among never smokers and lower among overweight patients (1.55 (1.21-1.98) and 0.56 (0.41-0.76), respectively). Patients with early-onset colorectal cancer were more likely to be diagnosed with advanced stage disease, to have received systemic treatments regardless of stage at diagnosis, and were less likely to be ever smokers or overweight