Histological and global gene expression analysis of the ‘lactating’ pigeon crop

Background: Both male and female pigeons have the ability to produce a nutrient solution in their crop for the nourishment of their young. The production of the nutrient solution has been likened to lactation in mammals, and hence the product has been called pigeon ‘milk’. It has been shown that pigeon ‘milk’ is essential for growth and development of the pigeon squab, and without it they fail to thrive. Studies have investigated the nutritional value of pigeon ‘milk’ but very little else is known about what it is or how it is produced. This study aimed to gain insight into the process by studying gene expression in the ‘lactating’ crop.
Results: Macroscopic comparison of ‘lactating’ and non-’lactating’ crop reveals that the ‘lactating’ crop is enlarged and thickened with two very obvious lateral lobes that contain discrete rice-shaped pellets of pigeon ‘milk’. This was characterised histologically by an increase in the number and depth of rete pegs extending from the basal layer of the epithelium to the lamina propria, and extensive proliferation and folding of the germinal layer into the superficial epithelium. A global gene expression profile comparison between ‘lactating’ crop and non-’lactating’ crop showed that 542 genes are up-regulated in the ‘lactating’ crop, and 639 genes are down-regulated. Pathway analysis revealed that genes up-regulated in ‘lactating’ crop were involved in the proliferation of melanocytes, extracellular matrix-receptor interaction, the adherens junction and the wingless (wnt) signalling pathway. Gene ontology analysis showed that antioxidant response and microtubule transport were enriched in ‘lactating’ crop.
Conclusions: There is a hyperplastic response in the pigeon crop epithelium during ‘lactation’ that leads to localised cellular stress and expression of antioxidant protein-encoding genes. The differentiated, cornified cells that form the pigeon ‘milk’ are of keratinocyte lineage and contain triglycerides that are likely endocytosed as very low density lipoprotein (VLDL) and repackaged as triglyceride in vesicles that are transported intracellularly by microtubules. This mechanism is an interesting example of the evolution of a system with analogies to mammalian lactation, as pigeon ‘milk’ fulfils a similar function to mammalian milk, but is produced by a different mechanism.

Hybrid perspectives : defining the relativity of culture and identity through migration experiences

This paper examines how culture and identity can be relatively defined through hybrid perspectives in relation to migration experiences. Addressing and portraying definitions of culture and identity is crucial in understanding how notions of such issues connect and initiate the migrant subject through new experiences, perspectives and ways of being. In enunciating the transitions from home to a new place, and elaborating on the rupture of an inherited culture and grounded identity, I refer to them through self-reflexive perspectives. The search for meaning through appraisals of cultural lineage and linguistic capital through a Diaspora, a post colonial history and lived life experiences from my home country, pre-empts the ambivalent and hybrid status in defining culture(s) and identit(ies). It is crucial to recognise how challenges for adaptation to new culture, language, societal norms, and differences in class, nationality, race and gender play specific roles in the migrant experience. My current experiences of migration to Australia are narrations of encountered difficulties, fears, inhibitions, new aspirations, perceptions and perspectives, which map an ‘identity crisis.’ From this narrative structure, I investigate through my ongoing PhD study, how my artistic expression and representations progress towards experiences, and themes that metaphorically reflect, inspire and enact the hybrid structures of culture(s) and identit(ies). Explored reflexively my representations suggest how the ‘liminal space’ or the ‘third space,’ (Bhabha, 1990) express transitions about the ‘self’ and my artistic expression, which enable further reflection and positions to emerge and extend to metaphorical expressions.

Ex vivo expansion of haematopoietic stem/progenitor cells from human umbilical cord blood on acellular scaffolds prepared from MS-5 stromal cell line

Lineage-specific expansion of haematopoietic stem/progenitor cells (HSPCs) from human umbilical cord blood (UCB) is desirable because of their several applications in translational medicine, e.g. treatment of cancer, bonemarrowfailure and immunodeficiencies. The currentmethods forHSPC expansion use either cellular feeder layers and/or soluble growth factors and selected matrix components coated on different surfaces. The use of cell-free extracellular matrices from bone marrow cells for this purpose has not previously been reported. We have prepared insoluble, cell- free matrices from a murine bone marrow stromal cell line (MS-5) grown under four different conditions, i.e. in presence or absence of osteogenic medium, each incubated under 5% and 20% O2 tensions. These acellularmatrices were used as biological scaffolds for the lineage-specific expansion of magnetically sorted CD34+ cells and the results were evaluated by flow cytometry and colony-forming assays. We could get up to 80-fold expansion of some HSPCs on one of the matrices and our results indicated that oxygen tension played a significant role in determining the expansion capacity of the matrices. A comparative proteomic analysis of the matrices indicated differential expression of proteins, such as aldehyde dehydrogenase and gelsolin, which have previously been identified as playing a role in HSPC maintenance and expansion. Our approach may be of value in identifying factors relevant to tissue engineering-based ex vivo HSPC expansion, and itmay also provide insights into the constitution of the niche in which these cells reside in the bone marrow.

Alternative TEL-JAK2 fusions associated with T-cell acute lymphoblastic leukemia and atypical chronic myelogenous leukemia dissected in zebrafish

Background Chromosomal translocations resulting in alternative fusions of the human TEL (ETV6) and JAK2 genes have been observed in cases of acute lymphoblastic leukemia and chronic myelogenous leukemia, but a full understanding of their role in disease etiology has remained elusive. In this study potential differences between these alternative TEL-JAK2 fusions, including their lineage specificity, were investigated.

Design and Methods TEL-JAK2 fusion types derived from both T-cell acute lymphoblastic leukemia and atypical chronic myelogenous leukemia were generated using the corresponding zebrafish tel and jak2a genes and placed under the control of either the white blood cell-specific spi1 promoter or the ubiquitously-expressed cytomegalovirus promoter. These constructs were injected into zebrafish embryos and their effects on hematopoiesis examined using a range of molecular approaches. In addition, the functional properties of the alternative fusions were investigated in vitro.

Results Injection of the T-cell acute lymphoblastic leukemia-derived tel-jak2a significantly perturbed lymphopoiesis with a lesser effect on myelopoiesis in zebrafish embryos. In contrast, injection of the atypical chronic myelogenous leukemia-derived tel-jak2a resulted in significant perturbation of the myeloid compartment. These phenotypes were observed regardless of whether expressed in a white blood cell-specific or ubiquitous manner, with no overt cellular proliferation outside of the hematopoietic cells. Functional studies revealed subtle differences between the alternative forms, with the acute lymphoblastic leukemia variant showing higher activity, but reduced downstream signal transducer and activator of transcription activation and decreased sensitivity to JAK2 inhibition. JAK2 activity was required to mediate the effects of both variants on zebrafish hematopoiesis.

Conclusions This study indicates that the molecular structure of alternative TEL-JAK2 fusions likely contributes to the etiology of disease. The data further suggest that this class of oncogene exerts its effects in a cell lineage-specific manner, which may be due to differences in downstream signaling.

Tyk2 and Stat3 regulate brown adipose tissue differentiation and obesity

Mice lacking the Jak tyrosine kinase member Tyk2 become progressively obese due to aberrant development of Myf5+ brown adipose tissue (BAT). Tyk2 RNA levels in BAT and skeletal muscle, which shares a common progenitor with BAT, are dramatically decreased in mice placed on a high-fat diet and in obese humans. Expression of Tyk2 or the constitutively active form of the transcription factor Stat3 (CAStat3) restores differentiation in Tyk2−/− brown preadipocytes. Furthermore, Tyk2−/− mice expressing CAStat3 transgene in BAT also show improved BAT development, normal levels of insulin, and significantly lower body weights. Stat3 binds to PRDM16, a master regulator of BAT differentiation, and enhances the stability of PRDM16 protein. These results define Tyk2 and Stat3 as critical determinants of brown fat lineage and suggest that altered levels of Tyk2 are associated with obesity in both rodents and humans.

Utilising silk fibroin membranes as scaffolds for the growth of tympanic membrane keratinocytes, and application to myringoplasty surgery

Background: Chronic tympanic membrane perforations can cause significant morbidity. The term myringoplasty describes the operation used to close such perforations. A variety of graft materials are available for use in myringoplasty, but all have limitations and few studies report post-operative hearing outcomes. Recently, the biomedical applications of silk fibroin protein have been studied. This material’s biocompatibility, biodegradability and ability to act as a scaffold to support cell growth prompted an investigation of its interaction with human tympanic membrane keratinocytes. Methods and materials: Silk fibroin membranes were prepared and human tympanic membrane keratinocytes cultured. Keratinocytes were seeded onto the membranes and immunostained for a number of relevant protein markers relating to cell proliferation, adhesion and specific epithelial differentiation. Results: The silk fibroin scaffolds successfully supported the growth and adhesion of keratinocytes, whilst also maintaining their cell lineage. Conclusion: The properties of silk fibroin make it an attractive option for further research, as a potential alternative graft in myringoplasty.

Bone marrow chimeras and c-fms conditional ablation (mafia) mice reveal an essential role for resident myeloid cells in lipopolysaccharide/TLR4-induced corneal inflammation

The mammalian cornea contains an extensive network of resident macrophages and dendritic cells. To determine the role of these cells in LPS-induced corneal inflammation, TLR4−/− mice were sublethally irradiated and reconstituted with bone marrow cells from either enhanced GFP (eGFP)+/C57BL/6 or eGFP+/TLR4−/− mice. The corneal epithelium was abraded, LPS was added topically, and cellular infiltration to the corneal stroma and development of corneal haze were examined after 24 h. TLR4−/− mice reconstituted with C57BL/6, but not TLR4−/− bone marrow cells donor cells were found to cause infiltration of eGFP+ cells to the cornea, including neutrophils, and also increased corneal haze compared with saline-treated corneas. In a second experimental approach, corneas of transgenic macrophage Fas induced apoptosis (Mafia) mice were stimulated with LPS. These mice express eGFP and a suicide gene under control of the c-fms promoter, and systemic treatment with the FK506 dimerizer (AP20187) causes Fas-mediated apoptosis of monocytic cells. AP20187-treated mice had significantly fewer eGFP+ cells in the cornea than untreated mice. After stimulation with LPS neutrophil recruitment and development of corneal haze were impaired in AP20187-treated mice compared with untreated controls. Furthermore, LPS induced CXCL1/KC and IL-1α production within 4 h in corneas of untreated Mafia mice, which is before cellular infiltration; however, cytokine production was impaired after AP20187 treatment. Together, results from both experimental approaches demonstrate an essential role for resident corneal monocytic lineage cells (macrophages and dendritic cells) in development of corneal inflammation.

The Melbourne Diabetes Prevention Study (MDPS) : study protocol for a randomized controlled trial

Background
Worldwide, type 2 diabetes (T2DM) prevalence has more than doubled over two decades. In Australia, diabetes is the second highest contributor to the burden of disease. Lifestyle modification programs comprising diet changes, weight loss and moderate physical activity, have been proven to reduce the incidence of T2DM in high risk individuals.

As part of the Council of Australia Governments, the State of Victoria committed to develop and support the diabetes prevention program ‘Life! Taking action on diabetes’ (Life!) which has direct lineage from effective clinical and implementation trials from Finland and Australia. The Melbourne Diabetes Prevention Study (MDPS) has been set up to evaluate the effectiveness and cost-effectiveness of a specific version of the Life! program.

Methods/design
We intend to recruit 796 participants for this open randomized clinical trial; 398 will be allocated to the intervention arm and 398 to the usual care arm. Several methods of recruitment will be used in order to maximize the number of participants. Individuals aged 50 to 75 years will be screened with a risk tool (AUSDRISK) to detect those at high risk of developing T2DM. Those with existing diabetes will be excluded. Intervention participants will undergo anthropometric and laboratory tests, and comprehensive surveys at baseline, following the fourth group session (approximately three months after the commencement of the intervention) and 12 months after commencement of the intervention, while control participants will undergo testing at baseline and 12 months only.

The intervention consists of an initial individual session followed by a series of five structured-group sessions. The first four group sessions will be carried out at two week intervals and the fifth session will occur eight months after the first group session. The intervention is based on the Health Action Process Approach (HAPA) model and sessions will empower and enable the participants to follow the five goals of the Life! program.

Discussion
This study will determine whether the effect of this intervention is larger than the effect of usual care in reducing central obesity and cardiovascular risk factors and thus the risk of developing diabetes and cardiovascular disease. Also it will evaluate how these two options compare economically.

Reassessing the theorisation of community experience within the digitally mediated, global context

This paper argues that the changing environment in which community experience occurs requires re-theorisation within the digitally mediated, global context. A range of work has certainly emerged addressing this, but there is more to be done, including tracing a theoretical lineage of community studies.

Beginning with the early Chicago School, community was described as geographically bounded. Decades later, community experience meditated by digital technology has been commonly understood to be about virtual community. Ironically, many virtual community scholars have perpetuated the Chicago School perspective in examinations of online groupings, the only difference being that such ‘boundedness’ now referred to relatively fixed locations in cyberspace.

As an emerging alternative, a parallel range of literature has focused upon the immersion of ICT-mediated social relations into everyday life. It is argued that Wellman’s networked individualism provides a way to integrate the online/offline mediated social experience, however it is not a sufficiently complete metaphor to describe spatially distributed, mediated community experiences. From the work of Robert Park, a member of the early Chicago School, the idea of the social ‘ecology’ of place can be adapted to provide a connecting thread into digitally mediated ecologies of community experience. 

Drawing the line: Chinese calligraphy, cultural materialisms and the “remixing of remix"

Remix in writing has very different expressions, and is grounded in very different legal, philosophical and creative materialisms, in Western and Chinese cultures. The infringement of authors’ Intellectual Property Rights (IPRs) in China is not only an irritant for Chinese-Western commercial and legal relations. It also points to different formations of the creative and legal domains across global space, and serves to introduce notions of creativity and originality that are largely unfamiliar in the West. Calligraphy, as a pictorial and material mode of writing, comprises a practice of Chinese remix in which the apprentice traces the lines of the master’s work: repetition of Yun 韵 (‘composed body movements’) stimulates the expression of Qing 情 (‘feelings’). What appears from a distance to be slavish imitation actually involves a philosophy of learning (or more precisely, of ‘unlearnt learning’) that, bypassing plagiarism’s traps, effectively ‘remixes remix’ as a creative model no longer dependent on the familiar Western rationales for the legitimacy of remix as appropriation, homage and/or pastiche. To see this though, one has to deploy a Taoist rather than a Confucian framework in the analysis of calligraphic practices. The case of Kathy Acker, allied with the work of Gilles Deleuze, reveals a largely invisible lineage of Taoist-influenced remix in Western creative writing. In this way, calligraphy emerges as a model of remix relevant to all forms of writing—for all writing is material, whether calligraphic or not. Further, as Acker shows, the materiality of writing constantly replenishes its remixing with cultural elements that may not be otherwise visible.

Georgics of the mind and the architecture of fortune: Francis Bacon's therapeutic ethics

This essay complements recent work by Soreana Corneanu situating Bacon’s epistemology in a larger lineage of literature concerning ‘cultura animi’ in early modern Europe, by focusing on Bacon’s conception of a therapeutic philosophical ‘Georgics of the mind’ in The Advancement of Learning, the Essays, and other texts. We aim to show firstly (in Part 2) how Bacon’s conception of human nature, and the importance of habit and custom, reflects the ancient pagan thinkers’ justifications of philosophical therapeutics. Attention will also be paid in this connection to Bacon’s sensitivity to another marker of ancient therapeutic philosophy as Pierre Hadot in particular has recently presented it: the proliferation of different rhetorical and literary forms aiming at different pedagogic, therapeutic, and psychogogic aims. Part 3 then will examine Bacon’s changes in practical or ‘magistral’ philosophy, carried out on the therapeutic ethical grounds which Part 2 has examined, but proposing a much more active ‘architecture of fortune’ to philosophical and political aspirants.

Using gene-history and expression analyses to assess the involvement of LGI genes in human disorders

Mutations in the leucine-rich, glioma-inactivated 1 gene, LGI1, cause autosomal-dominant lateral temporal lobe epilepsy via unknown mechanisms. LGI1 belongs to a subfamily of leucine-rich repeat genes comprising four members (LGI1–LGI4) in mammals. In this study, both comparative developmental as well as molecular evolutionary methods were applied to investigate the evolution of the LGI gene family and, subsequently, of the functional importance of its different gene members. Our phylogenetic studies suggest that LGI genes evolved early in the vertebrate lineage. Genetic and expression analyses of all five zebrafish lgi genes revealed duplications of lgi1 and lgi2, each resulting in two paralogous gene copies with mostly nonoverlapping expression patterns. Furthermore, all vertebrate LGI1 orthologs experience high levels of purifying selection that argue for an essential role of this gene in neural development or function. The approach of combining expression and selection data used here exemplarily demonstrates that in poorly characterized gene families a framework of evolutionary and expression analyses can identify those genes that are functionally most important and are therefore prime candidates for human disorders.

An issues paper: the roots/routes of Australian architecture: elements of an alternative architectural history

The dynamism and mobility of architects in their approach to architecturaldesign practice provides a context that emphasises that architecture, likeculture, is not static or rooted in place, but is intricately configured throughthe dual processes of locality and mobility – both physical and theoretical. Theproduction of architecture in Australia, as in other immigrant-rich societies,provides a case for reinforcing the theory that architectural mobility and travelare integral to the architecture of place.This issues paper sets out to re-examine the contribution of geo-culturalinfluences upon Australia’s architectural lineage and considers a diverse rangeof themes across an equally broad timeframe; British colonial transpositions; thedissemination of Modernism in Australia; the latent contribution of mid-twentiethcentury European émigré architects; and the secreted history of Australia’sAsian architecture. Common to all, however, is the notion of architecturaltranslation as a process of influences transmitted, transposed or adapted toother contexts. It uses Australia as the focus from which to consider how globalcriticism, ideas and theories have travelled and continue to travel transverselyacross time and place, from the late-eighteenth century well into the twenty-first.This paper investigates translations through narratives, processes, networks andtraces of architectural manifestations and begins to draw lines of influence.

Monotreme lactation protein is highly expressed in monotreme milk and provides antimicrobial protection

Monotremes (platypus and echidna) are the descendants of the oldest ancestor of all extant mammals distinguished from other mammals by mode of reproduction. Monotremes lay eggs following a short gestation period and after an even briefer incubation period, altricial hatchlings are nourished over a long lactation period with milk secreted by nipple-less mammary patches located on the female's abdomen. Milk is the sole source of nutrition and immune protection for the developing young until weaning. Using transcriptome and mass spectrometry analysis of milk cells and milk proteins, respectively, a novel Monotreme Lactation Protein (MLP) was identified as a major secreted protein in milk. We show that platypus and short-beaked echidna MLP genes show significant homology and are unique to monotremes. The MLP transcript was shown to be expressed in a variety of tissues; however, highest expression was observed in milk cells and was expressed constitutively from early to late lactation. Analysis of recombinant MLP showed that it is an N-linked glycosylated protein and biophysical studies predicted that MLP is an amphipathic, α-helical protein, a typical feature of antimicrobial proteins. Functional analysis revealed MLP antibacterial activity against both opportunistic pathogenic Staphylococcus aureus and commensal Enterococcus faecalis bacteria but showed no effect on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Salmonella enterica. Our data suggest that MLP is an evolutionarily ancient component of milk-mediated innate immunity absent in other mammals. We propose that MLP evolved specifically in the monotreme lineage supporting the evolution of lactation in these species to provide bacterial protection, at a time when mammals lacked nipples.

The top 10 oomycete pathogens in molecular plant pathology

Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens which threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant-pathogenic oomycete species based on scientific and economic importance. In total, we received 263 votes from 62 scientists in 15 countries for a total of 33 species. The Top 10 species and their ranking are: (1) Phytophthora infestans; (2, tied) Hyaloperonospora arabidopsidis; (2, tied) Phytophthora ramorum; (4) Phytophthora sojae; (5) Phytophthora capsici; (6) Plasmopara viticola; (7) Phytophthora cinnamomi; (8, tied) Phytophthora parasitica; (8, tied) Pythium ultimum; and (10) Albugo candida. This article provides an introduction to these 10 taxa and a snapshot of current research. We hope that the list will serve as a benchmark for future trends in oomycete research.