Molecular systematics of the Australian freshwater shrimp, Paratya australiensis

Molecular genetic date was used to test the taxonomic hypothesis of a single species of the freshwater shrimp, Paratya australiensis. While the results identified significant cryptic diversity, clear species boundaries could not be defined. The results of this study defy a simple taxonomic conclusion but are suggestive of incipient speciation.

Molecular aspects of boundary lubrication by human lubricin : effect of disulfide bonds and enzymatic digestion

Lubricin (LUB) is a glycoprotein of the synovial cavity of human articular joints, where it serves as an antiadhesive, boundary lubricant, and regulating factor for the cartilage surface. It has been proposed that these properties are related to the presence of a long, extended, heavily glycosylated and highly hydrated mucinous domain in the central part of the LUB molecule. In this work, we show that LUB has a contour length of 220 ± 30 nm and a persistence length of ≤10 nm. LUB molecules aggregate in oligomers where the protein extremities are linked by disulfide bonds. We have studied the effect of proteolytic digestion by chymotrypsin and removal of the disulfide bonds, both of which mainly affect the N− and C− terminals of the protein, on the adsorption, normal forces, friction (lubrication) forces, and wear of LUB layers adsorbed on smooth, negatively charged mica surfaces, where the protein naturally forms lubricating polymer brush-like layers. After in situ digestion, the surface coverage was drastically reduced, the normal forces were altered, and both the coefficient of friction and the wear were dramatically increased (the COF increased to μ = 1.1−1.9), indicating that the mucinous domain was removed from the surface. Removal of disulfide bonds did not change the surface coverage or the overall features of the normal forces; however, we find an increase in the friction coefficient from μ = 0.02−0.04 to μ = 0.13−1.17 in the pressure regime below 6 atm, which we attribute to a higher affinity of the protein terminals for the surface. The necessary condition for LUB to be a good lubricant is that the protein be adsorbed to the surface via its terminals, leaving the central mucin domain free to form a low-friction, surface-protecting layer. Our results suggest that this “end-anchoring” has to be strong enough to impart the layer a sufficient resistance to shear, but without excessively restricting the conformational freedom of the adsorbed proteins.

Molecular systematic studies of freshwater prawns of the genus Macrobrachium

Freshwater prawns in the genus Macrobrachium are found throughout the tropical and subtropical regions of the world, however, evolutionary relationships are poorly understood. Using molecular techniques taxonomic uncertainty is resolved and the evolution and distribution of this enigmatic genus across a range of taxonomic and geographic levels is examined.

Cellular and molecular components of plant defence against pathogens

This project investigated how plants respond to invading pathogens using microscopic, biochemical and genetic approaches. The development of transgenic plants containing the green fluorescent protein cloned from jellyfish enabled a new approach to studying plant defence genes. In particular, the role and involvement of the plant gene PAL1 was analysed.

Creatine transporter expression in skeletal muscle

Creatine is an important molecule involved in providing energy to the body. Its major stores are in skeletal muscle. The creatine transporter protein (CreaT) mRNA is believed to be responsible for the uptake of the majority of creatine in skeletal muscle. This thesis examined factors that might have affected the expression of the creatine transporter in skeletal muscle.

Effects of vegetarianism and exercise on muscle creatine loading and gene expression

The results of this thesis indicate that vegetarianism and prior exercise can increase skeletal muscle creatine loading. The mechanisms by which these phenomena occur remain unknown but may be related to changes in the gene expression of a cellular pump within the muscle known as the "creatine transporter".

Interactions of Plasmodiophora brassicae with Arabidopsis thaliana

The host-pathogen interaction study between Arabidopsis thaliana and Plasmodiophora brassicae was conducted at cellular and molecular level for a better understanding of the pathogen. Gene expression studies conducted therin at the early time points during the infection process of P. brassicae discovered new information on the components of compatibility.

Bovine lactoferrin : potential antioxidant effector molecule in colon carcinoma

This research generated important insight into the antioxidant capacity and effector molecule capability of bovine lactoferrin in both its Apo- (iron free) and metal saturated forms within the gastrointestinal system, giving rise to bovine lactoferrin's potential at regulating oxidative stress associated signalling molecules within colon carcinoma.

Advances in the treatment of malignant gliomas

Local control with surgery, radiation, and temozolomide chemotherapy remain the pillars of treatment for high-grade gliomas. Novel therapeutic strategies, including a variety of antiangiogenic agents, are under investigation. One of these agents, bevacizumab, was recently given accelerated approval by the US Food and Drug Administration as a single agent for recurrent glioblastoma. Recent trial results are generating important clinical questions regarding which patients to treat and when, and how best to monitor response. Encouraging results of recent studies are driving willingness to undertake aggressive treatment and to improve outcomes in this population. In this era, better understanding of biology, molecular aspects of cancer, and clinical trial methodology are crucial for clinicians. This review focuses on recent advances in the treatment malignant gliomas, especially antiangiogenic therapy.

Muscle damage and inflammation during recovery from exercise

Unaccustomed exercise consisting of eccentric (i.e., lengthening) muscle contractions often results in muscle damage characterized by ultrastructural alterations in muscle tissue, clinical signs and symptoms (e.g., reduced muscle strength and range of motion, increased muscle soreness and swelling, efflux of myocellular proteins). The time course of recovery following exercise-induced muscle damage depends on the extent of initial muscle damage, which in turn is influenced by the intensity and duration of exercise, joint angle/muscle length and muscle groups used during exercise. The effects of these factors on muscle strength, soreness and swelling are well characterized. By contrast, much less is known about how they affect intramuscular inflammation and molecular aspects of muscle adaptation/remodeling. Although inflammation has historically been viewed as detrimental for recovery from exercise, it is now generally accepted that inflammatory responses-if tightly regulated-are integral to muscle repair and regeneration. Animal studies have revealed that other cell types including mast cells, eosinophils, CD8 and T regulatory lymphocytes, fibro-adipogenic progenitors and pericytes also help to facilitate muscle tissue regeneration. However, more research is required to determine whether these cells respond to exercise-induced muscle damage. A large body of research has investigated the efficacy of physicotherapeutic, pharmacological and nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage, with mixed results. More research is needed to examine if/how these treatments influence inflammation and muscle remodeling during recovery from exercise.

Molecular taxonomy and phylogenetics of some species of Australian palaemonid shrimps

The evolutionary history and classification of the palaemonid shrimps has been the subject of constant speculation and debate. At present, all major systematic treatments have been based on morphological characteristics. To help resolve the phylogenetic relationships, and thus enable the creation of a classification system that reflects evolutionary history, a region of the 16S mitochondrial rRNA gene was sequenced for a number of Australian Palaemonidae. The resulting phylogenetic analyses indicated the presence of major anomalies in the current classification of Australian Palaemonidae. Significantly, three species belonging to three separate genera, Macrobrachium intermedium, Palaemon serenus, and Palaemonetes australis, are closely related, with genetic differences more characteristic with that of congeneric species. The results also demonstrate non-monophyly in Australian palaemonids with respect to both Palaemonetes and Macrobrachium.

A preliminary study of 16S rRNA sequence variation in Australia Macrobrachium shrimps (Palaemonidae: Decapoda) reveals inconsistencies in their current classification

The systematic relationships among Australian palaemonid shrimps have been the subject of speculation for some time. A preliminary phylogenetic study was undertaken to clarify the relationships of five species, Macrobrachium intermedium (Stimpson), M. australiense (Holthuis), M. atactum (Riek), M. rosenbergii (de Man) and Palaemon serenus (Heller), using 16S rRNA mitochondrial gene sequences. Phylogenetic analyses indicated inconsistencies with the current classification in two respects. First, M. intermedium formed a very well-supported clade with P. serenus distinct from M. australiense, M. atactum and M. rosenbergii. Second, the two species from inland Australia, M. australiense and M. atactum, showed a high level of genetic similarity over a substantial geographic range, suggesting that they may represent conspecific populations. The taxonomic and biogeographic implications of these findings for Macrobrachium in Australia are discussed.

Molecular and cellular aspects of copper transport in developing mammals

Copper is an essential trace element that requires tightly regulated homeostatic mechanisms to ensure adequate supplies without any toxic effects because of the ability of the metal ion to catalyze the formation of free radicals. The Cu-ATPases, ATP7A and ATP7B, play an important role in the physiological regulation of copper. Adequate supplies of copper are particularly important in developing animals, and in humans this is illustrated by mutations of ATP7A that cause the copper deficiency condition Menkes disease, which is fatal in early childhood. In contrast, mutations in ATP7B result in the genetic toxicosis, Wilson disease. We propose that the physiological regulation of copper is accomplished mainly by the intracellular copper-regulated trafficking of the Cu-ATPases. This process allows the overall copper status in the body to be maintained when levels of copper in the diet alter. A study of the defects in mouse models of Menkes and Wilson diseases has demonstrated that both ATPases play an important role in supplying copper to the developing fetus and neonate

An illustration of variable precision rough set theory : The gender classification of the European barn swallow (Hirundo rustica)

This paper introduces a new technique in the investigation of object classification and illustrates the potential use of this technique for the analysis of a range of biological data, using avian morphometric data as an example. The nascent variable precision rough sets (VPRS) model is introduced and compared with the decision tree method ID3 (through a ‘leave n out’ approach), using the same dataset of morphometric measures of European barn swallows (Hirundo rustica) and assessing the accuracy of gender classification based on these measures. The results demonstrate that the VPRS model, allied with the use of a modern method of discretization of data, is comparable with the more traditional non-parametric ID3 decision tree method. We show that, particularly in small samples, the VPRS model can improve classification and to a lesser extent prediction aspects over ID3. Furthermore, through the ‘leave n out’ approach, some indication can be produced of the relative importance of the different morphometric measures used in this problem. In this case we suggest that VPRS has advantages over ID3, as it intelligently uses more of the morphometric data available for the data classification, whilst placing less emphasis on variables with low reliability. In biological terms, the results suggest that the gender of swallows can be determined with reasonable accuracy from morphometric data and highlight the most important variables in this process. We suggest that both analysis techniques are potentially useful for the analysis of a range of different types of biological datasets, and that VPRS in particular has potential for application to a range of biological circumstances.