QUANTIFYING INHABITATION, FEEDING AND CONNECTIVITY BETWEEN ADJACENT ESTUARINE AND COASTAL REGIONS FOR THREE COMMERCIALLY IMPORTANT MARINE FISHES

1. Estuaries are regarded as valuable nursery habitats for many commercially important marine fishes. Recruitment of fish from estuarine nursery habitats to adult marine populations is considered important for maintenance of fishable stocks, but most evidence for this is qualitative. Effective and timely implementation of estuarine conservation and fisheries management plans may be aided by quantitative assessment of this habitat connectivity. 2. This thesis reports upon the quantification of inhabitation, feeding and connectivity between adjacent estuarine and coastal regions for Common sole (Solea solea), European sea bass (Dicentrarchus labrax) and Whiting (Merlangius merlangus). Sample collection was focused in the Thames Estuary and adjacent coastal regions. 3. Two techniques were employed: (i) stable isotope analysis of soft tissues for tracing feeding signals; and (ii) elemental analysis of fish otoliths for tracing patterns of fish movement and residency. 4. Analysis of δ13C, δ15N and δ34S data identified significant differences in isotopic signatures between estuarine and coastal invertebrates, and allowed re-classification to sample sites with 98.8% accuracy. 5. Using invertebrate data as source indicators, stable isotope data classified juvenile fishes to the region in which they fed using stable isotope data. Feeding signals primarily reflected physiological (freshwater tolerance) and functional (mobility) differences between species. 6. Mixing models calculated estuarine contributions to adult muscle tissue isotopic composition. Juvenile bass have an affinity for estuarine feeding, followed by greater plasticity (individual level) in habitat choice as older fish, facilitated by their mobility and tolerance of low salinities. Sole show this plasticity (population level) in estuarine-coastal feeding as juveniles, and then lower plasticity with more consistently marine diets as adults. Whiting exhibited plasticity (individual level) as both juveniles and adults. 7. Chemical composition of juvenile fish otoliths reflected their region of collection (95- 100% accuracy). Misclassifications were indicative of between-habitat movement by whiting. Only juvenile sole showed significant energetic benefits of an estuarine existence. 8. Adult otolith chemistry data supported the stable isotope results. Variable plasticity in the use of estuarine and coastal resources was revealed, depending upon the species. 9. This research provides quantitative insight into resource use and estuarine-coastal habitat connectivity for these three species, as well as valuable guidance for similar future applications of soft-tissue stable isotope analysis and elemental analysis of fish otoliths.Centre for Environment, Fisheries and Aquaculture Science

Considerations requiring investigation in the allocation of funds for library materials at the University of Cape Town

Bibliography: leaves 212-223.With very few exceptions, all libraries, be they national, university, provincial, municipal or special, are funded to a greater or lesser degree by public money. Thus as Malan says, this subsidy presupposes that their services and stock should be used in the public interest. (Malan, 1978:83). In the case of South African university libraries, which constitutes the province of this study, the parent institution currently receives a subsidy according to the provisions laid down in the van Wyk de Vries Commission's recommendations. (de Vries, 1974). Included in this subsidy are formulae designed specifically to enable the university library to operate, i.e. allowances are made both for personnel and for the acquisition of library materials. It is in this latter connection that the present inves- tigation has been made, viz. the allocation of funds received from the State via the university administration to the teaching and research units to enable them to fulfil their basic function

Identifying gene locus associations with promyelocytic leukemia nuclear bodies using immuno-TRAP.

Important insights into nuclear function would arise if gene loci physically interacting with particular subnuclear domains could be readily identified. Immunofluorescence microscopy combined with fluorescence in situ hybridization (immuno-FISH), the method that would typically be used in such a study, is limited by spatial resolution and requires prior assumptions for selecting genes to probe. Our new technique, immuno-TRAP, overcomes these limitations. Using promyelocytic leukemia nuclear bodies (PML NBs) as a model, we used immuno-TRAP to determine if specific genes localize within molecular dimensions with these bodies. Although we confirmed a TP53 gene-PML NB association, immuno-TRAP allowed us to uncover novel locus-PML NB associations, including the ABCA7 and TFF1 loci and, most surprisingly, the PML locus itself. These associations were cell type specific and reflected the cell's physiological state. Combined with microarrays or deep sequencing, immuno-TRAP provides powerful opportunities for identifying gene locus associations with potentially any nuclear subcompartment

The Effects of Whole Body Vibration on Bone Mineral Density for a Person with a Spinal Cord Injury: A Case Study

Bone mineral density (BMD) loss is a medical concern for individuals with spinal cord injury (SCI). Concerns related to osteoporosis have lead researchers to use various interventions to address BMD loss within this population. Whole body vibration (WBV) has been reported to improve BMD for postmenopausal women and suggested for SCI. The purpose of this case study was to identify the effects of WBV on BMD for an individual with SCI. There were three progressive phases (standing only, partial standing, and combined stand with vibration), each lasting 10 weeks. Using the least significant change calculation, significant positive changes in BMD were reported at the trunk (0.46 g/cm2) and spine (.093 g/cm2) for phase 3 only. Increases in leg lean tissue mass and reduction in total body fat were noted in all three phases

Reduced Mobility of the Alternate Splicing Factor (Asf) through the Nucleoplasm and Steady State Speckle Compartments

Compartmentalization of the nucleus is now recognized as an important level of regulation influencing specific nuclear processes. The mechanism of factor organization and the movement of factors in nuclear space have not been fully determined. Splicing factors, for example, have been shown to move in a directed manner as large intact structures from sites of concentration to sites of active transcription, but splicing factors are also thought to exist in a freely diffusible state. In this study, we examined the movement of a splicing factor, ASF, green fluorescent fusion protein (ASF–GFP) using time-lapse microscopy and the technique fluorescence recovery after photobleaching (FRAP). We find that ASF–GFP moves at rates up to 100 times slower than free diffusion when it is associated with speckles and, surprisingly, also when it is dispersed in the nucleoplasm. The mobility of ASF is consistent with frequent but transient interactions with relatively immobile nuclear binding sites. This mobility is slightly increased in the presence of an RNA polymerase II transcription inhibitor and the ASF molecules further enrich in speckles. We propose that the nonrandom organization of splicing factors reflects spatial differences in the concentration of relatively immobile binding sites

Nucleosome repositioning via loop formation

Active (catalysed) and passive (intrinsic) nucleosome repositioning is known to be a crucial event during the transcriptional activation of certain eucaryotic genes. Here we consider theoretically the intrinsic mechanism and study in detail the energetics and dynamics of DNA-loop-mediated nucleosome repositioning, as previously proposed by Schiessel et al. (H. Schiessel, J. Widom, R. F. Bruinsma, and W. M. Gelbart. 2001. {\it Phys. Rev. Lett.} 86:4414-4417). The surprising outcome of the present study is the inherent nonlocality of nucleosome motion within this model -- being a direct physical consequence of the loop mechanism. On long enough DNA templates the longer jumps dominate over the previously predicted local motion, a fact that contrasts simple diffusive mechanisms considered before. The possible experimental outcome resulting from the considered mechanism is predicted, discussed and compared to existing experimental findings