Biogeographic patterns in alpine New Zealand : using nuclear and chloroplast loci to investigate divergence and secondary contact in Notothlaspi (Brassicaceae) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Plant Biology at Massey University, Manawatū, New Zealand

Lineage divergence and hybridisation are integral processes in biological evolution. In New Zealand alpine environments, isolation by distance and isolation by environment are two key processes that drive evolutionary change in plant lineages. The Pleistocene climate fluctuations isolated and re-introduced lineages, and complex geological substrates host several edaphic endemic floras. However, to our knowledge, plant diversification has not been studied at a population genetic scale in New Zealand alpine environments. Here, the three species in the alpine genus Notothlaspi (Brassicaceae) were selected to investigate divergence across heterogeneous landscapes. Three molecular marker types were trialled in Notothlaspi: thirty new nuclear microsatellites, five universal chloroplast loci, and RAPDseq-generated SNPs. Twelve suitable microsatellite markers were selected, and the trnL-F and psbA-trnH loci produced high quality sequences with inter- and intra-specific polymorphisms. The RAPDseq scheme identified 41 promising polymorphic loci with several SNPs. The twelve microsatellite markers, and the trnL-F chloroplast locus, were used to investigate the spatial distribution of genetic variation and to infer historical influences on the evolution of Notothlaspi. Within N. australe, an unexplained biogeographic split within the Kahurangi National park was discovered that deviates from expectations under isolation by distance. This suggests diverged ancestral groupings, such as in glacial refugia, and/or local adaptation to substrate. Within N. rosulatum, the trnL-F chloroplast locus distinguished populations in Marlborough with greater resolution than the nuclear microsatellite data, indicating a prevalence of pollen-mediated geneflow. A potential past or present hybrid zone was also identified in the Richmond Forest Park, an area of range overlap between all three species. Here, we describe the first population genetic investigation in the alpine regions of the northern South Island of New Zealand. The findings make important contributions to future studies on biogeography, and the role of heterogeneous environments on the diversification of the New Zealand flora

Heat and osmotic stress responses of probiotic Lactobacillus rhamnosus HN001 (DR20) in relation to viability after drying

The viability of lactic acid bacteria in frozen, freeze-dried, and air-dried forms is of significant commercial interest to both the dairy and food industries. In this study we observed that when prestressed with either heat (50ºC) or salt (0.6 M NaCl), Lactobacillus rhamnosus HN001 (also known as DR20) showed significant (P < 0.05) improvement in viability compared with the nonstressed control culture after storage at 30ºC in the dried form. To investigate the mechanisms underlying this stress-related viability improvement in L. rhamnosus HN001, we analyzed protein synthesis in cultures subjected to different growth stages and stress conditions, using two-dimensional gel electrophoresis and N-terminal sequencing. Several proteins were up- or down-regulated after either heat or osmotic shock treatments. Eleven proteins were positively identified, including the classical heat shock proteins GroEL and DnaK and the glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, enolase, phosphoglycerate kinase, and triose phosphate isomerase, as well as tagatose 1,6-diphosphate aldolase of the tagatose pathway. The phosphocarrier protein HPr (histidine-containing proteins) was up-regulated in cultures after the log phase irrespective of the stress treatments used. The relative synthesis of an ABC transport-related protein was also up-regulated after shock treatments. Carbohydrate analysis of cytoplasmic contents showed higher levels (20 ± 3 μg/mg of protein) in cell extracts (CFEs) derived from osmotically stressed cells than in the unstressed control (15 ± 3 μg/mg of protein). Liquid chromatography of these crude carbohydrate extracts showed significantly different profiles. Electrospray mass spectrometry analysis of CFEs revealed, in addition to normal mono-, di-, tri-, and tetrasaccharides, the presence of saccharides modified with glycerol

Clandinin T. Influence of dietary gangliosides on neonatal brain development. Nutr Rev 2009;67

Gangliosides are sialic acid-containing glycosphingolipids. Ganglioside

The Role of Gangliosides in Neurodevelopment

Gangliosides are important components of neuronal cell membranes and it is widely accepted that they play a critical role in neuronal and brain development. They are functionally involved in neurotransmission and are thought to support the formation and stabilization of functional synapses and neural circuits required as the structural basis of memory and learning. Available evidence, as reviewed herein, suggests that dietary gangliosides may impact positively on cognitive functions, particularly in the early postnatal period when the brain is still growing. Further, new evidence suggests that the mechanism of action may be through an effect on the neuroplasticity of the brain, mediated through enhanced synaptic plasticity in the hippocampus and nigro-striatal dopaminergic pathway

Supplementation with complex milk lipids during brain development promotes neuroplasticity without altering myelination or vascular density

Background: Supplementation with complex milk lipids (CML) during postnatal brain development has been shown to improve spatial reference learning in rats. Objective: The current study examined histo-biological changes in the brain following CML supplementation and their relationship to the observed improvements in memory. Design: The study used the brain tissues from the rats (male Wistar, 80 days of age) after supplementing with either CML or vehicle during postnatal day 10–80. Immunohistochemical staining of synaptophysin, glutamate receptor-1, myelin basic protein, isolectin B-4, and glial fibrillary acidic protein was performed. The average area and the density of the staining and the numbers of astrocytes and capillaries were assessed and analysed. Results: Compared with control rats, CML supplementation increased the average area of synaptophysin staining and the number of GFAP astrocytes in the CA3 sub-region of the hippocampus (p<0.01), but not in the CA4 sub-region. The supplementation also led to an increase in dopamine output in the striatum that was related to nigral dopamine expression (p<0.05), but did not alter glutamate receptors, myelination or vascular density. Conclusion: CML supplementation may enhance neuroplasticity in the CA3 sub-regions of the hippocampus. The brain regions-specific increase of astrocyte may indicate a supporting role for GFAP in synaptic plasticity. CML supplementation did not associate with postnatal white matter development or vascular remodelling