The polyamines putrescine, spermidine and spermine are essential for cell growth and differentiation. The biosynthesis of polyamines are tightly regulated by feedback mechanisms involving two enzymes, namely ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC). This thesis deals with the mechanisms behind the polyamine-mediated feedback control of these enzymes. The poly

Nematode-trapping fungi are soil-living organisms with the unique ability to capture and infect free-living nematodes. The interest in studying these fungi arises from their potential use as biological control agents for plant- and animal-parasitic nematodes. To enter the parasitic stage, nematode-trapping fungi develop different kinds of trapping structures. In order to understand more about the

Fluidised bed thermal gasification of biomass is an effective route that results in 100 % conversion of the fuel. In contrast to chemical, enzymatic or anaerobic methods of biomass treatment, the thermal conversion leaves no contaminated residue after the process. The product gas evolved within thermal conversion can be used in several applications such as: fuel for gas turbines, combustion engine

A fundamental function of long-term memory is the ability to retrieve a specific memory when encountering a retrieval cue. The purpose of this dissertation was to further our understanding of such cued recall by investigating the temporal dynamics from the presentation of the retrieval cue until the target memory is recalled. Retrieval cues are often related with several memories. When such a retr

Many microorganisms have developed mechanisms to protect themselves against attack from the complement system of the host. One possible mechanism for a microorganism to evade complement attack is to bind a human complement regulator, which may allow the microorganism to down-regulate complement activation. This thesis describes studies of such interactions between human C4b-binding protein (C4BP),

The pro-inflammatory mediators leukotrienes have shown to be important players in the pathogenesis of diseases like asthma and inflammatory bowel disease (IBD). Patients suffering from IBD have been found to have an increased risk of developing colon cancer. Since leukotrienes have been shown in increased concentrations in stools of IBD patients we hypothesise that LTD4 can play a role in the deve

Following the transection and repair of major nerve trunks in the forearm, the functional outcome is influenced by mechanisms in the peripheral, as well as in the central nervous system. In the present thesis the interest is focused on assessment of the outcome after nerve repair, central nervous factors influencing the outcome, and sense substitution to compensate for sensory loss. A new model in

During the last decade it has been discovered that around 2% of the soil-living prokaryotes belong to the domain Archaea. In many soils the most abundant archaeal group is the ammonia-oxidizing archaea (AOA) that, in addition to ammonia-oxidizing bacteria (AOB), preform the first and rate-limiting step in the nitrification process. The knowledge of factors that regulates the archaeal abundance and

This thesis deals with Ca2+ binding to proteins, electrostatic interactions in and between proteins as well as inter- and intramolecular interactions. A computer program was developed to determine Ca2+ binding constants from experimental titration data of proteins. We further studied the effect of deamidation in the Ca2+ binding site of Calbindin D9k on the Ca2+ binding and cooperativity and concl

Females often base their choice of mates on the expression, size or intensity, of male sexual ornaments. Indicator models of sexual selection assume that females assess male genetic quality through the expression of these secondary sexual characters. Several mechanisms that link the expression of sexual ornaments to genetic quality have been suggested. Many models assume that this link is individu

Apoptosis is a defined process for cells to commit suicide through a set of biochemical and morphological cell changes. Activated apoptotic signals converge on the mitochondria, leading to permeabilization of mitochondrial membranes and release of different apoptosis regulatory proteins into the cytosol. With my studies I wanted to investigate the importance of polyamines in the regulation of apop

The method of microdialysis has been adapted for ocular use. It is a technique for monitoring concentrations of different molecules in a tissue in vivo. It is based on the principle of diffusion through a semipermeable membrane. The membrane is mounted on a soft plastic shaft, connected to an inlet and an outlet tube. The whole device, called microdialysis probe, was implanted into the vitreous bo

Basement membranes are sheet like structures underlying epithelial, endothelial, adipocytes, muscle and peripheral nerve cells. Laminins are an important family of basement membrane proteins implicated in various biological functions through their interactions with cell surface receptors. Laminins are trimers composed of a, b and g chains. Integrins, dystroglycan and other transmembrane glycoprote

Angiotensin II (Ang II) is a potent vasoconstrictor that is implicated in the pathogenesis of hypertension, heart failure and atherosclerosis. In this thesis, the efficacy and safety of Ang II receptor blockers (ARB) were evaluated. The vasomotor effects of Ang II in endothelium-denuded human coronary arteries were characterized by in vitro pharmacology and the Ang II receptor mRNA levels were qua

Toothed whales (Odontocetes) use echolocation to navigate and find food in dark or murky waters. A wide range of innovative studies has since the 1960:s been used to characterize their echolocation beam and map out their echolocation skills. In order to render high quality recordings of the sounds emitted by these animals, advanced measurement systems are required. There are still interesting env

This thesis explores a novel transistor technology based on vertical InAs nanowires, which could be considered both for low-power high-frequency analog applications and for replacing Si CMOS in the continued scaling of digital electronics. The potential of this device - the vertical InAs nanowire MOSFET – lies in the combination of the outstanding transport properties of InAs and the improved elec

Polyelectrolytes are polymers bearing ionisable groups, which, in polar solvents, can dissociate into charged polymer chains (polyelectrolytes) and small counterions. In aqueous solutions, polyelectrolytes interact strongly with other macroions and in particular they tend to associate with objects of opposite charge and form complexes. Nearly all industrial and biological process involves solution

Systemic sclerosis (scleroderma) is a connective tissue disease which, in various ways, influences an individual’s ability to participate in everyday occupations. The general objective of this work was to elucidate the consequences of scleroderma with respect to hand function, everyday occupations and wellbeing, in order to provide a knowledge base suitable for occupational therapy interventions.

Bread products are one of the most common and important foods in our daily diet, and have been since ancient times. Although it has a long history and comes in many variations, the staling phenomenon of bread is still not fully known. Staling is a complex phenomenon that includes all the physical and sensorial changes occurring in bread during storage. To gain a better understanding of staling, di