Characteristics of white-chinned petrels Procellaria aequinoctialis Linnaeus in New Zealand waters : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Ecology at Massey University, Palmerston North, New Zealand

Current taxonomy of the white-chinned petrel suggests that all populations are similar enough to be a single global taxon, Procellaria aequinoctialis Linnaeus. This thesis challenges that view with an analysis of morphological characteristics of white-chinned petrels from fisheries bycatch in the New Zealand Exclusive Economic Zone (EEZ). The two main aims were: first, to determine if white-chinned petrels in New Zealand waters comprise one taxon; and second, to determine if white-chinned petrels in New Zealand waters fit the proposition of a global taxon. Morphological characteristics included: standard external measurements (head, bill, tarsus, wing and tail measurements), descriptions (area of white on the chin and bodily descriptions), and measurements of internal organs of a sample of 723 bycatch white-chinned petrels. Twenty-five white-chinned petrel study skins from breeding islands in the South Pacific. Indian and Atlantic Oceans, and 29 study skins from birds caught off Chile were also measured for comparison with the bycatch birds. I compared a range of external measurements from the bycatch sample taken by myself and 'the Laboratory' (measurements and descriptions of white-chinned petrels taken by C.J.R. Robertson and E. Bell) to estimate the measurement error between multiple observers measuring the same sample of birds. Results clearly showed very little measurement error between the two observers, and the small amount of error was biologically insignificant. I found two cluster groups of bycatch white-chinned petrels, the 'Antipodes Island group' (n = 105) which was significantly larger in most external measurements than the 'Auckland Island group' (n = 45). Using discriminant analysis I could differentiate 93% males of the 'Antipodes Island group' versus the 'Auckland Island group' based on culmen and tail length. I could also differentiate 92% of females from the 'Antipodes Island group' versus the 'Auckland Island group' based on head and bill length, culmen depth at the base and wing length. Discriminant analysis indicates that the Antipodes Island population male and female white-chinned petrel study skins related closest to the 'Antipodes Island group' and the Auckland Island, South Indian Ocean, South Atlantic Ocean, and Chile male and female white-chinned petrel study skins related closest to the 'Auckland Island group'. The results suggest that within the New Zealand EEZ there are two taxa of white-chinned petrels based on external morphology: 'aequinoctialis' Linnaeus, the smaller sized white-chinned petrels from the Auckland Islands; and 'steadi' Mathews, the larger sized white-chinned petrels from Antipodes Island and most likely Campbell Island. The results also suggest that, globally, the external morphology of white-chinned petrels can be used to identify two taxa: 'aequinoctialis' Linnaeus, the smaller sized white-chinned petrels which comprise the Auckland Islands, the South Indian Ocean, and the South Atlantic Ocean populations; and 'steadi' Mathews, the larger sized white-chinned petrels which comprise the Antipodes Islands population. Further, most white-chinned petrels caught off Chile are likely to be from the Auckland Island breeding population or South Atlantic Ocean breeding populations

Distribution of tissue progenitors within the shield region of the zebrafish gastrula

The zebrafish has emerged as an important model system for the experimental analysis of vertebrate development because it is amenable to genetic analysis and because its optical clarity allows the movements and the differentiation of individual cells to be followed in vivo. In this paper, we have sought to characterize the spatial distribution of tissue progenitors within the outer cell layers of the embryonic shield region of the early gastrula. Single cells were labeled by iontophoretic injection of fluorescent dextrans. Subsequently, we documented their position with respect to the embryonic shield and their eventual fates. Our data show that progenitor cells of the neural, notochordal, somitic and endodermal lineages were all present within the embryonic shield region, and that these progenitors were arranged as intermingled populations. Moreover, close to the midline, there was evidence for significant biases in the distribution of neural and notochord progenitors between the layers, suggesting some degree of radial organization within the zebrafish embryonic shield region. The distributions of tissue progenitors in the zebrafish gastrula differ significantly from those in amphibians; this bears not only on interpretations of mutant phenotypes and in situ staining patterns, but also on our understanding of morphogenetic movements during gastrulation and of neural induction in the zebrafish

Characterizing the zebrafish organizer: microsurgical analysis at the early-shield stage

The appearance of the embryonic shield, a slight thickening at the leading edge of the blastoderm during the formation of the germ ring, is one of the first signs of dorsoventral polarity in the zebrafish embryo. It has been proposed that the shield plays a role in fish embryo patterning similar to that attributed to the amphibian dorsal lip. In a recent study, we fate mapped many of the cells in the region of the forming embryonic shield, and found that neural and mesodermal progenitors are intermingled (Shih, J. and Fraser, S.E. (1995) Development 121, 2755–2765), in contrast to the coherent region of mesodermal progenitors found at the amphibian dorsal lip. Here, we examine the fate and the inductive potential of the embryonic shield to determine if the intermingling reflects a different mode of embryonic patterning than that found in amphibians. Using the microsurgical techniques commonly used in amphibian and avian experimental embryology, we either grafted or deleted the region of the embryonic shield. Homotopic grafting experiments confirmed the fates of cells within the embryonic shield region, showing descendants in the hatching gland, head mesoderm, notochord, somitic mesoderm, endoderm and ventral aspect of the neuraxis. Heterotopic grafting experiments demonstrated that the embryonic shield can organize a second embryonic axis; however, contrary to our expectations based on amphibian research, the graft contributes extensively to the ectopic neuraxis. Microsurgical deletion of the embryonic shield region at the onset of germ ring formation has little effect on neural development: embryos with a well-formed and well-patterned neuraxis develop in the complete absence of notochord cells. While these results show that the embryonic shield is sufficient for ectopic axis formation, they also raise questions concerning the necessity of the shield region for neural induction and embryonic patterning after the formation of the germ ring

Rhombomere rotation reveals that multiple mechanisms contribute to the segmental pattern of hindbrain neural crest migration

Hindbrain neural crest cells adjacent to rhombomeres 2 (r2), r4 and r6 migrate in a segmental pattern, toward the first, second and third branchial arches, respectively. Although all rhombomeres generate neural crest cells, those arising from r3 and r5 deviate rostrally and caudally (J. Sechrist, G. Serbedzija, T. Scherson, S. Fraser and M. Bronner-Fraser (1993) Development 118, 691–703). We have altered the rostrocaudal positions of the cranial neural tube, adjacent ectoderm/mesoderm or presumptive otic vesicle to examine tissue influences on this segmental migratory pattern. After neural tube rotation, labeled neural crest cells follow pathways generally appropriate for their new position after grafting. For example, when r3 and r4 were transposed, labeled r3 cells migrated laterally to the second branchial arch whereas labeled r4 cells primarily deviated caudally toward the second arch, with some cells moving rostrally toward the first. In contrast to r4 neural crest cells, transposed r3 cells leave the neural tube surface in a polarized manner, near the r3/4 border. Surprisingly, some labeled neural crest cells moved directionally toward small ectopic otic vesicles that often formed in the ectoderm adjacent to grafted r4. Similarly, they moved toward grafted or displaced otic vesicles. In contrast, surgical manipulation of the mesoderm adjacent to r3 and r4 had no apparent effects. Our results offer evidence that neural crest cells migrate directionally toward the otic vesicle, either by selective attraction or pathway-derived cues

Outreach at the match: a cautionary tale

John Baruch, Ulrich Kolb, Helen Fraser and Jen Heyes share some of the pitfalls they encountered when combining outreach with football; they advocate a different sort of wow factor

Effect of Preventive Home Visits by a Nurse on the Outcomes of Frail Elderly People in the Community: a randomized controlled trial

Background: Timely recognition and prevention of health problems among elderly people have been shown to improve their health. In this randomized controlled trial the authors examined the impact of preventive home visits by a nurse compared with usual care on the outcomes of frail elderly people living in the community. Methods: A screening questionnaire identified eligible participants (those aged 70 years or more at risk of sudden deterioration in health). Those randomly assigned to the visiting nurse group were assessed and followed up in their homes for 14 months. The primary outcome measure was the combined rate of deaths and admissions to an institution, and the secondary outcome measure the rate of health services utilization, during the 14 months; these rates were determined through a medical chart audit by a research nurse who was blind to group allocation. Results: The questionnaire was mailed to 415 elderly people, of whom 369 (88.9%) responded. Of these, 198 (53.7%) were eligible, and 142 consented to participate and were randomly assigned to either the visiting nurse group (73) or the usual care group (69). The combined rate of deaths and admissions to an institution was 10.0% in the visiting nurse group and 5.8% in the usual care group (p = 0.52). The rate of health services utilization did not differ significantly between the 2 groups. Influenza and pneumonia vaccination rates were significantly higher in the visiting nurse group (90.1% and 81.9%) than in the usual care group (53.0% and 0%) (p \u3c 0.001). Interpretation: The trial failed to show any effect of a visiting nurse other than vastly improved vaccination coverage

The pathway of hepatitis C virus mRNA recruitment to the human ribosome.

Eukaryotic protein synthesis begins with mRNA positioning in the ribosomal decoding channel in a process typically controlled by translation-initiation factors. Some viruses use an internal ribosome entry site (IRES) in their mRNA to harness ribosomes independently of initiation factors. We show here that a ribosome conformational change that is induced upon hepatitis C viral IRES binding is necessary but not sufficient for correct mRNA positioning. Using directed hydroxyl radical probing to monitor the assembly of IRES-containing translation-initiation complexes, we have defined a crucial step in which mRNA is stabilized upon initiator tRNA binding. Unexpectedly, however, this stabilization occurs independently of the AUG codon, underscoring the importance of initiation factor-mediated interactions that influence the configuration of the decoding channel. These results reveal how an IRES RNA supplants some, but not all, of the functions normally carried out by protein factors during initiation of protein synthesis

An etiological and pathological study of tuberculosis of the bones and the joints

Under the heading of Etiology I have investigated two points:A. The type of Bacillus which causes the disease, whether Human or Bovine, and more especially its relation to the question of milk supply.B. The paths by which the infection reaches the Bones and the Joints.These investigations have been almost entirely experimental.I have studied the Pathology of Bone and Joint Tubercle, partly from the disease as produced experimentally, and partly from Pathological Material