Modeling Aging and Degenerative Disease in DNA Repair-Deficient Drosophila

As cells age, they accumulate DNA damage that can lead to genomic instability, mutations, and cancer. DNA repair proteins, such as Werner (WRN), have essential roles preventing and repairing DNA damage caused by stress from the environment, DNA replication errors, and free radicals. In humans, mutations in WRN lead to Werner syndrome (WS), a heritable disease characterized by patients’ early onset of aging, increased risk of cancer and other age-related pathologies. My lab uses Drosophila mutant in the fly homolog of WRN, WRNexo, to elucidate its role in DNA repair and aging. While human WRN has both an exonuclease and helicase domain, the Drosophila homolog, WRNexo, only contains an exonuclease domain, providing us with a unique model to study exonuclease-specific functions largely uninvestigated in human cells. Previous studies have shown that WRNexo has exonuclease activity and acts on similar DNA substrate as human WRN. Similarly, flies with WRNexo mutations, (WRNexo Δ ) are sensitive to reagents that cause DNA replication stress demonstrating that WRNexo is important in maintaining normal DNA replication

Introducing new functions into (and onto) virus-like particles

Leviphage Qß and PP7 are well studied viruses that infect E. coli. They also provide highly stable and tailorable capsid protein structures that can be manipulated in a number of ways by the molecular biologist and chemist. We will describe our work with both particles, designed to give them new binding, shielding, and catalytic properties. This involves the expression of hybrid particles bearing catalytic protein domains on the inside or outside, the use of standard polymerization methods to grow organic polymers from the surface or into the interior of the particles, and the marriage of these particles with degradable hydrogel carriers Please click Additional Files below to see the full abstract

Carborane–β-cyclodextrin complexes as a supramolecular connector for bioactive surfaces

Supramolecular chemistry provides an attractive entry to generate dynamic and well-controlled bioactive surfaces. Novel host–guest systems are urgently needed to provide a broader affinity and applicability portfolio. A synthetic strategy to carborane–peptide bioconjugates was therefore developed to provide an entry to monovalent supramolecular functionalization of β-cyclodextrin coated surfaces. The β-cyclodextrin·carborane–cRGD surfaces are formed efficiently and with high affinity as demonstrated by IR-RAS, WCA, and QCM-D, compare favourable to existing bio-active host–guest surface assemblies, and display an efficient bioactivity, as illustrated by a strong functional effect of the supramolecular system on the cell adhesion and spreading properties. Cells seeded on the supramolecular surface displaying bioactive peptide epitopes exhibited a more elongated morphology, focal adhesions, and stronger cell adhesion compared to control surfaces. This highlights the macroscopic functionality of the novel supramolecular immobilization strategy

Effects of Photopollution on Circadian Activity Rhythms

Many aspects of organismal behavior and metabolism are modulated by biological clocks that oscillate with 24-hour (circadian) rhythms. These circadian clocks synchronize to environmental cues, such as cycles of light and dark, and allow organisms to anticipate changing environmental conditions and make use of temporal niches. The circadian clocks’ function, as well as the biological processes they modulate, can be altered by excess artificial lighting (photopollution). Photopollution levels in Chicago are some of the highest in the world, making it an ideal location to investigate the ecological and health impacts of nighttime light. While photopollution’s effects on specific species (e.g. sea turtles) have been well documented, research across wider, urban populations is limited. Using a combination of laboratory and field studies, we examined the effects of relevant nighttime light levels on circadian rhythms in two model organisms: Drosophila melanogaster (fruit flies) and Mus musculus (house mice). Activity patterns were analyzed using TriKinetics activity monitors and running wheels with Clocklab data collection software, respectively. For both species locomotor activity was collected continuously for the duration of the experiments and levels of nighttime light were manipulated to replicate levels of photopollution found in the Chicagoland area (0 to 36 lux). Significant activity pattern differences were found for both species. Specifically, nighttime light changed total activity, the length of the active phase, and the amplitude of the activity rhythm in both species. In addition, field data on 12 wildlife species were collected from 83 camera traps (provided by the Urban Wildlife Institute at the Lincoln Park Zoo) across the Chicago metropolitan area. Photographic information was combined with data from satellite imagery to develop 24-hour activity profiles, and analyze for variations in activity based on nighttime light levels and season. Results show that nocturnal animals’ total activity and duration of the active period decreased with the introduction of nighttime light. Taken together, these data demonstrate that the effects of photopollution are far reaching and can impact a variety of organisms. By combining both laboratory and field data, we hope to better understanding the varying impacts of photopollution and expand our understanding of the anthropogenic effects of artificial nighttime light on circadian clocks, behavior, and the environment

Redrafting Ohio\u27s Advance Directive Laws

The Bioethics Network of Ohio (BENO) held its second annual conference on June 12, 1992 at Ohio Dominican College, Columbus, Ohio. Attendees recommended that a Task Force\u27 review Ohio\u27s Durable Power of Attorney for Health Care (DPAHC) and Modified Uniform Rights for the Terminally Ill (MURTIA) laws and suggest changes that would retain the basic structure of these provisions but also simplify and clarify their meaning. The Task Force completed a draft in six months and circulated it to approximately 450 individual and institutional BENO members. About one hundred members responded and this article incorporates most of their comments

Two neutrino double beta decay within the ξ\xi-approximation

We examine the contributions of odd-parity nuclear operators to the two-neutrino double beta decay $0^+\rightarrow 0^+$ amplitude, which come from the $P$-wave Coulomb corrections to the electron wave functions and the recoil corrections to the nuclear currents. Although they are formally of higher order in $\alpha Z/2$ or $v/c$ of the nucleon than the usual Fermi and Gamow-Teller matrix elements, explicit calculations performed within the QRPA show that they are significant when confronted with the experimental data.Comment: 9 pages, latex, no figure

Sequential uncaging with green light can be achieved by fine-tuning the structure of a dicyanocoumarin chromophore

We report the synthesis and photochemical properties of a series of dicyanocoumarinylmethyl (DEAdcCM)- and dicyanocoumarinylethyl (DEAdcCE)-based photocages of carboxylic acids and amines with absorption maximum around 500 nm. Photolysis studies with green light have demonstrated that the structure of the coumarin chromophore as well as the nature of the leaving group and the type of bond to be photocleaved (ester or carbamate) have a strong influence on the rate and efficiency of the uncaging process. These experimental observations were also supported by DFT calculations. Such differences in deprotection kinetics have been exploited to sequentially photolyze two dicyanocoumarin-caged model compounds (e.g. benzoic acid and ethylamine), and open the way to increasing the number of functional levels that can be addressed with light in a single system, particularly when combining dicyanocoumarin caging groups with other photocleavable protecting groups that remain intact under green light irradiation

Nové inhibitory HIV proteasy: návrh, synthesa a testování aktivity

More than 20 years after its discovery HIV protease still remains one of the primary targets in HIV treatment. Currently there are 9 approved protease inhibitors on the market. However, due to immense replication rate and the high error prone nature of reverse transcriptase, resistance to each of them has already been described. Therefore, the search for new protease inhibitors with different binding mode is still active. A novel type of protease inhibitors (1, 4-benzodiazepine analogs) was recently discovered in our laboratory. Even though this new class of inhibitors is highly potent (Ki' in range of 10-9 ), it also has several undesirable qualities, such as low solubility and a high number of stereogenic centers. Primary objective of this study was to try to prepare more soluble compounds with lower number of possible stereoisomers, enzymologically characterize its binding to the wild-type and mutated HIV protease and to determine its structure in the complex with the enzyme. A small library of 1, 4-benzodiazepine inhibitors of HIV protease was synthesized and fully characterized using NMR spectroscopy and mass spectroscopy. The number of stereogenic centers was successfully reduced from 4 to 2 without loosing activity of the inhibitor. The improvement in solubility was always associated with a..

Inhibitory proteas jako nástroj: Návrh, syntéza a testování inhibitorů HIV proteasy a GCPII

Hlavním cílem teto práce je příprava inhibitorů jako nástroje pro studium a potenciální zásah do procesů regulovaných proteasami. V této práci jsem se zaměřil na dvě významné proteasy: HIV protreasu (HIV PR), která hraje nepostradatelnou roli během dozrávaní virových částic, a glutamátkarboxypeptidasu II (GCPII), důležitý marker rakoviny nádorů prostaty. Racionální návrh inhibitorů medicínsky významných enzymů slouží hned dvěma účelům: za prvé, jak se ukázalo, jsou inhibitory účinnými virostatiky (HIV proteasa je pravděpodobně vůbec nejlepším příkladem úspěšného vývoje léčiv pomocí racionálního návrhu) a za druhé, - v kontextu této disertační práce pravděpodobně i důležitěji - inhibitory mohou sloužit též jako nástroje pro rozšifrování základních biologických otázek týkajících se regulace, načasování a časoprostorové kontroly takových zásadních procesů, jako je maturace virových částic či vznik rakovinových buněk. Proteasa viru lidské imunitní nedostatečnosti Virus lidské imunitní nedostatečnosti (HIV) způsobující AIDS zabil v průběhu posledních čtyř desetiletí vice než 40 milionů lidí, z čehož 1,5 milionu zemřelo jen v minulém roce. Nakažených pacientů je v současné chvíli více než 35 milionů a toto číslo se stále zvyšuje, zejména v méně rozvinutých zemích sub-saharské Afriky. Především kvůli...This dissertation thesis focuses on creating tools for the analysis and potential therapeutic intervention in the biological processes regulated by proteolysis. I focus on two important proteolytic enzymes: HIV-1 protease, which is indispensable for the polyprotein processing of the nascent virus and thus for the development of infectious viral particle, and glutamate carboxypeptidase II, a tumor marker and a neuropeptidase from the prostate and central nervous system. Rational design of inhibitors of these therapeutically relevant enzymes serves two purposes: firstly, protease inhibitors were shown to be powerful drugs (HIV protease is in fact the example of successful drug development driven by structural biology). Secondly, and in the context of this thesis perhaps more importantly, inhibitors of medicinally relevant proteases might serve as tools for the elucidation of basic biological questions concerning regulation, timing and spatiotemporal control of such key processes as virus maturation or cancer development. The experimental work described in this thesis summarizes my results in both these areas. Human Immunodeficiency Virus Protease Human immunodeficiency virus (HIV), a causative agent of AIDS, has been estimated to kill close to 40 million people during the past four decades with 1.5...Katedra biochemieDepartment of BiochemistryFaculty of SciencePřírodovědecká fakult