Antibiotic resistance, caused by widespread use of antibiotics, leads to bacterial infections that are difficult, if not impossible, to treat and is a major worldwide health concern. Currently... Show moreAntibiotic resistance, caused by widespread use of antibiotics, leads to bacterial infections that are difficult, if not impossible, to treat and is a major worldwide health concern. Currently Methicillin-resistant Staphylococcus aureus (MRSA) is the most commonly identified antibiotic-resistant pathogen in clinical medicine worldwide. The spread of MRSA highlights the urgent need for alternative therapies, such as vaccination.Wall teichoic acids (WTAs), prime constituents of the Gram-positive cell wall, can function as effective antigenic epitopes and are therefore promising candidates for the development of a conjugate vaccine against S. aureus infections. WTAs are anionic poly-ribitol phosphate (RboP) chains attached to the peptidoglycan and they have a fundamentol role in the physiology in the bacteria.Since isolation from the bacteria of WTAs leads to heterogenous mixtures of fragments and bacterial contaminations, organic synthesis is the method of choice to generate WTA-fragments with pre-defined substitution patterns in higher purity and in larger amounts, allowing detailed immunological studies that can aid in future vaccine development.This Thesis presents methods to synthesize various WTA-fragments from Staphylococcus aureus and Enterococcus faecalis and their applications. Show less
Technological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in... Show moreTechnological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in applied biomedical research, using selected cases. We look at the use of zebrafish embryos as disease models, taking fetal alcohol syndrome and tuberculosis as examples. We discuss advances in imaging, in culture techniques (including microfluidics), and in drug delivery (including new techniques for the robotic injection of compounds into the egg). The use of zebrafish embryos in early stages of drug safety-screening is discussed. So too are the new behavioral assays that are being adapted from rodent research for use in zebrafish embryos, and which may become relevant in validating the effects of neuroactive compounds such as anxiolytics and antidepressants. Readouts, such as morphological screening and cardiac function, are examined. There are several drawbacks in the zebrafish model. One is its very rapid development, which means that screening with zebrafish is analogous to __screening on a run-away train.__ Therefore, we argue that zebrafish embryos need to be precisely staged when used in acute assays, so as to ensure a consistent window of developmental exposure. We believe that zebrafish embryo screens can be used in the pre-regulatory phases of drug development, although more validation studies are needed to overcome industry scepticism. Finally, the zebrafish poses no challenge to the position of rodent models: it is complementary to them, especially in early stages of drug research. Show less
