Intermediate filament protein assembly : a proteomic approach

Intermediate filament proteins (IFPs) form the main structural elements of a wool fibre. The IFPs of wool are comprised of two families; the acidic type I family and the neutral-basic type II family. During follicle development, one type I and one type II IFP develop into an obligate heteropolymer, which, through a series of associations with other heteropolymers, forms an intermediate filament. Two-dimensional polyacrylamide gel electrophoresis (20-PAGE) methods have been used to provide high-resolution separation of wool IFPs. Improvements in the method for maintaining reducing conditions and chaotrope constitution, combined with low % T polyacrylamide gels, allowed the high-resolution separation of the two keratin IFP families and their individual family members. The IFPs were separated to produce a clearly defined spot pattern, with numerous discrete minor spots not previously observed. Genomic studies have reported that there are eight genes which produce eight abundant IFPs in wool. It was hypothesised that the large number of additional spots seen on a 20-PAGE gel was due to post-translational modification (PTM) of the protein. Several common PTMs of proteins produce charge heterogeneity, including phosphorylation and glycosylation. However, analysis of wool IFPs by 20- PAGE techniques and mass spectrometry revealed no evidence of phosphorylation or glycosylation modifications. Conformational equilibria as a cause of protein charge heterogeneity has recently been reported. Investigations with both the type I and type II IFPs have shown that when single protein spots from a 20-PAGE separation are eluted, re-focused and re-electrophoresed, several spots are formed on both the acidic and basic side of the original spot. The cause of this heterogeneity is thought to be a conformational equilibrium between several different forms of the same protein in the rehydration solution used for the first dimension. This technique allowed the accurate assignment of IFPs resolved by 20-PAGE to protein families. Fractionation methods to separate the IFPs and intermediate filament associated proteins (IFAPs) were successfully developed. Further fractionation into the type I and type II IFPs was achieved along with partial success at isolating individual spots. In vitro assembly experiments with the different IFP families gives important information about the strength of different protein pairings. To date there are no reproducible, efficient, in vitro assembly conditions for keratinised wool IFPs. A comprehensive study to investigate assembly conditions for keratinised wool IFPs was undertaken. Assembly of filaments from IFPs was achieved after a partial digestion with chymotrypsin. Filaments were formed that varied in diameter from 10 to 40 nm, showing that higher ordered structures were being formed. This demonstrates that IFPs can be successfully assembled in vitro to form filamentous structures that may be able to be manipulated for biomaterial uses

At Home or Abroad: Tuvaluans Shaping a Tuvaluan Future

If development is to be sustainable, it is vital to plan and act with all possible futures in mind and for communities to be engaged and empowered so that development meets local needs. Throughout the international development community, there have been regular calls for people to act locally, but think globally. Yet, as challenges become more complex, it is no longer enough to simply think globally. Where possible futures involve losing one's land and country, people need to be able to participate in making a better future for themselves, their families and their communities beyond their own borders. Tuvalu is a country that faces multiple possible futures that may have severe impacts on its people, including the possibility of forced migration. As a country with many development needs, Tuvalu has created Te Kakeega II: National Strategies for Sustainable Development - 2005-2015, which acknowledges the need for participation and cross-sectoral collaboration. This thesis examines the mechanisms that exist to engage Tuvaluans in their development. It reviews whether Tuvaluans actually participate in these processes and whether there are any barriers to participation. It also investigates to what extent the mechanisms for participation are helping Tuvalu confront the contemporary and complex issue of climate change. People who are forced to migrate because of changes in their environment have no rights under international law and thus risk becoming disempowered. If Tuvaluans are forced to migrate because of climate change, they risk losing any gains they have made at home. Unlike many forced migration situations, Tuvaluans have time to participate in the preparations for such a future. To what extent are they enabled and empowered to do this? How, and who, do they think should prepare for this possible future

A Scaling Limit With Many Noncommutativity Parameters

We derive the worldsheet propagator for an open string with different magnetic fields at the two ends, and use it to compute two distinct noncommutativity parameters, one at each end of the string. The usual scaling limit that leads to noncommutative Yang-Mills can be generalized to a scaling limit in which both noncommutativity parameters enter. This corresponds to expanding a theory with U(N) Chan-Paton factors around a background U(1)^N gauge field with different magnetic fields in each U(1).Comment: 14 pages, harvma

The pregnant man: race, difference and subjectivity in Alan Paton’s Kalahari writing

In South African imaginative writing and scholarly research, there is currently an extensive and wide-ranging interest in the ‘Bushman’, either as a tragic figure of colonial history, as a contested site of misrepresentation, or even as an exemplary model of environmental consciousness. Writing and research about ‘Bushmen’ has not only become pervasive in the academy, but also a site of controversy and theoretical contestation. It is in this context that this paper investigates the meaning and significance of ‘Bushmen’ for Alan Paton, one of South Africa’s most well-known writers. Paton’s writing is not usually associated with ‘Bushman’ studies, yet this article shows that the ‘Bushman’ became a highly charged and ambivalent figure in his imagination. Paton’s problematic ideas are contextualised more carefully by looking at the broader context of South African letters. The article initially analyses Paton’s representation of ‘Bushmen’ in his Lost City of the Kalahari travel narrative (1956, published in 2005. Pietermaritzburg: KZN Press), and also discusses unpublished archival photographs. A study of the figure of the ‘Bushman’ throughout the entire corpus of his writing, ranging from early journalism to late autobiography, allows us to trace the shift of his views, enabling us to reflect not only on Paton’s thinking about racial otherness, but also gauge the extent to which his encounter with the Kalahari Bushmen destabilised his sense of self, finally also preventing the publication of the travelogueDepartment of HE and Training approved lis

Role of TNF-α in the Mechanisms Responsible for Preterm Delivery Induced by Stx2 in Rats

Shiga toxin-producing Escherichia coli (STEC) infections could be one of the causes of fetal morbimortality in pregnant women. We have previously reported that Shiga toxin type 2 (Stx2) causes preterm delivery in pregnant rats. In this study, we evaluate the role of tumor necrosis factor alpha (TNF-α), prostaglandins (PGs), and nitric oxide (NO) in the Stx2induced preterm delivery.Fil: Burdet, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentina; Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina;Fil: Sacerdoti, Flavia. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina;Fil: Cella, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentina;Fil: Franchi, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentina;Fil: Ibarra, Cristina Adriana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina

Biologics for paediatric severe asthma: Trick or TREAT?

No abstract available

Peroxidasin protein expression and enzymatic activity in metastatic melanoma cell lines are associated with invasive potential

Peroxidasin, a heme peroxidase, has been shown to play a role in cancer progression. mRNA expression has been reported to be upregulated in metastatic melanoma cell lines and connected to the invasive phenotype, but little is known about how peroxidasin acts in cancer cells. We have analyzed peroxidasin protein expression and activity in eight metastatic melanoma cell lines using an ELISA developed with an in-house peroxidasin binding protein. RNAseq data analysis confirmed high peroxidasin mRNA expression in the five cell lines classified as invasive and low expression in the three non-invasive cell lines. Protein levels of peroxidasin were higher in the cell lines with an invasive phenotype. Active peroxidasin was secreted to the cell culture medium, where it accumulated over time, and peroxidasin protein levels in the medium were also much higher in invasive than non-invasive cell lines. The only well-established physiological role of peroxidasin is in the formation of a sulfilimine bond, which cross-links collagen IV in basement membranes via catalyzed oxidation of bromide to hypobromous acid. We found that peroxidasin secreted from melanoma cells formed sulfilimine bonds in uncross-linked collagen IV, confirming peroxidasin activity and hypobromous acid formation. Moreover, 3-bromotyrosine, a stable product of hypobromous acid reacting with tyrosine residues, was detected in invasive melanoma cells, substantiating that their expression of peroxidasin generates hypobromous acid, and showing that it does not exclusively react with collagen IV, but also with other biomolecules