977 resultados para tissue structure
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Background The koala, Phascolarctos cinereus, is a biologically unique and evolutionarily distinct Australian arboreal marsupial. The goal of this study was to sequence the transcriptome from several tissues of two geographically separate koalas, and to create the first comprehensive catalog of annotated transcripts for this species, enabling detailed analysis of the unique attributes of this threatened native marsupial, including infection by the koala retrovirus. Results RNA-Seq data was generated from a range of tissues from one male and one female koala and assembled de novo into transcripts using Velvet-Oases. Transcript abundance in each tissue was estimated. Transcripts were searched for likely protein-coding regions and a non-redundant set of 117,563 putative protein sequences was produced. In similarity searches there were 84,907 (72%) sequences that aligned to at least one sequence in the NCBI nr protein database. The best alignments were to sequences from other marsupials. After applying a reciprocal best hit requirement of koala sequences to those from tammar wallaby, Tasmanian devil and the gray short-tailed opossum, we estimate that our transcriptome dataset represents approximately 15,000 koala genes. The marsupial alignment information was used to look for potential gene duplications and we report evidence for copy number expansion of the alpha amylase gene, and of an aldehyde reductase gene. Koala retrovirus (KoRV) transcripts were detected in the transcriptomes. These were analysed in detail and the structure of the spliced envelope gene transcript was determined. There was appreciable sequence diversity within KoRV, with 233 sites in the KoRV genome showing small insertions/deletions or single nucleotide polymorphisms. Both koalas had sequences from the KoRV-A subtype, but the male koala transcriptome has, in addition, sequences more closely related to the KoRV-B subtype. This is the first report of a KoRV-B-like sequence in a wild population. Conclusions This transcriptomic dataset is a useful resource for molecular genetic studies of the koala, for evolutionary genetic studies of marsupials, for validation and annotation of the koala genome sequence, and for investigation of koala retrovirus. Annotated transcripts can be browsed and queried at http://koalagenome.org
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Coral reefs provide an increasingly important archive of palaeoclimate data that can be used to constrain climate model simulations. Reconstructing past environmental conditions may also provide insights into the potential of reef systems to survive changes in the Earth’s climate. Reef-based palaeoclimate reconstructions are predominately derived from colonies of massive Porites, with the most abundant genus in the Indo-Pacific—Acropora—receiving little attention owing to their branching growth trajectories, high extension rates and secondary skeletal thickening. However, inter-branch skeleton (consisting of both coenosteum and corallites) near the bases of corymbose Acropora colonies holds significant potential as a climate archive. This region of Acropora skeleton is atypical, having simple growth trajectories with parallel corallites, approximately horizontal density banding, low apparent extension rates and a simple microstructure with limited secondary thickening. Hence, inter-branch skeleton in Acropora bears more similarities to the coralla of massive corals, such as Porites, than to traditional Acropora branches. Cyclic patterns of Sr/Ca ratios in this structure suggest that the observed density banding is annual in nature, thus opening up the potential to use abundant corymbose Acropora for palaeoclimate reconstruction.
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Spatial variation of seismic ground motions is caused by incoherence effect, wave passage, and local site conditions. This study focuses on the effects of spatial variation of earthquake ground motion on the responses of adjacent reinforced concrete (RC) frame structures. The adjacent buildings are modeled considering soil-structure interaction (SSI) so that the buildings can be interacted with each other under uniform and non-uniform ground motions. Three different site classes are used to model the soil layers of SSI system. Based on fast Fourier transformation (FFT), spatially correlated non-uniform ground motions are generated compatible with known power spectrum density function (PSDF) at different locations. Numerical analyses are carried out to investigate the displacement responses and the absolute maximum base shear forces of adjacent structures subjected to spatially varying ground motions. The results are presented in terms of related parameters affecting the structural response using three different types of soil site classes. The responses of adjacent structures have changed remarkably due to spatial variation of ground motions. The effect can be significant on rock site rather than clay site.
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DNA double-strand breaks (DSBs) are particularly lethal and genotoxic lesions, that can arise either by endogenous (physiological or pathological) processes or by exogenous factors, particularly ionizing radiation and radiomimetic compounds. Phosphorylation of the H2A histone variant, H2AX, at the serine-139 residue, in the highly conserved C-terminal SQEY motif, forming γH2AX, is an early response to DNA double-strand breaks1. This phosphorylation event is mediated by the phosphatidyl-inosito 3-kinase (PI3K) family of proteins, ataxia telangiectasia mutated (ATM), DNA-protein kinase catalytic subunit and ATM and RAD3-related (ATR)2. Overall, DSB induction results in the formation of discrete nuclear γH2AX foci which can be easily detected and quantitated by immunofluorescence microscopy2. Given the unique specificity and sensitivity of this marker, analysis of γH2AX foci has led to a wide range of applications in biomedical research, particularly in radiation biology and nuclear medicine. The quantitation of γH2AX foci has been most widely investigated in cell culture systems in the context of ionizing radiation-induced DSBs. Apart from cellular radiosensitivity, immunofluorescence based assays have also been used to evaluate the efficacy of radiation-modifying compounds. In addition, γH2AX has been used as a molecular marker to examine the efficacy of various DSB-inducing compounds and is recently being heralded as important marker of ageing and disease, particularly cancer3. Further, immunofluorescence-based methods have been adapted to suit detection and quantitation of γH2AX foci ex vivo and in vivo4,5. Here, we demonstrate a typical immunofluorescence method for detection and quantitation of γH2AX foci in mouse tissues.
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During fracture healing, many complex and cryptic interactions occur between cells and bio-chemical molecules to bring about repair of damaged bone. In this thesis two mathematical models were developed, concerning the cellular differentiation of osteoblasts (bone forming cells) and the mineralisation of new bone tissue, allowing new insights into these processes. These models were mathematically analysed and simulated numerically, yielding results consistent with experimental data and highlighting the underlying pattern formation structure in these aspects of fracture healing.
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(Sub)Urban Sexscapes brings together a collection of theoretically-informed and empirically rich case studies highlighting the contemporary and historical geographies and regulation of the commercial sex industry. Contributions in this edited volume examine the spatial and regulatory contours of the sex industry from a range of disciplinary perspectives—urban planning, urban geography, urban sociology, and, cultural and media studies—and geographical contexts—Australia, the UK, US and North Africa. In overall terms, (Sub)urban Sexscapes highlights the mainstreaming of commercial sex premises—sex shops, brothels, strip clubs and queer spaces—and products—sex toys, erotic literature and pornography—now being commonplace in night time economy spaces, the high street, suburban shopping centres and the home. In addition, the aesthetics of commercial and alternative sexual practices—BDSM and pornography—permeate the (sub)urban landscape via billboards, newspapers and magazines, television, music videos and the Internet. The role of sex, sexuality and commercialized sex, in contributing to the general character of our cities cannot be ignored. In short, there is a need for policy-makers to be realistic about the historical, contemporary and future presence of the sex industry. Ultimately, the regulation of the sex industry should be informed by evidence as opposed to moral panics.
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Weak cell-surface adhesion of cell lines to tissue culture surfaces is a common problem and presents technical limitations to the design of experiments. To overcome this problem, various surface coating protocols have been developed. However, a comparative and precise real-time measurement of their impact on cell behavior has not been conducted. The prostate cancer cell line LNCaP, derived from a patient lymph node metastasis, is a commonly used model system in prostate cancer research. However, the cells’ characteristically weak attachment to the surface of tissue culture vessels and cover slips has impeded their manipulation and analysis and use in high throughput screening. To improve the adherence of LNCaP cells to the culture surface, we compared different coating reagents (poly-L-lysine, poly-L-ornithine, collagen type IV, fibronectin, and laminin) and culturing conditions and analyzed their impact on cell proliferation, adhesion, morphology, mobility and gene expression using real-time technologies. The results showed that fibronectin, poly-L-lysine and poly-L-ornithine improved LNCaP cells adherence and provoked cell morphology alterations, such as increase of nuclear and cellular area. These coating reagents also induced a higher expression of F-actin and reduced cell mobility. In contrast, laminin and collagen type IV did not improve adherence but promoted cell aggregation and affected cell morphology. Cells cultured in the presence of laminin displayed higher mobility than control cells. All the coating conditions significantly affected cell viability; however, they did not affect the expression of androgen receptor-regulated genes. Our comparative findings provide important insight for the selection of the ideal coating reagent and culture conditions for the cancer cell lines with respect to their effect on proliferation rate, attachment, morphology, migration, transcriptional response and cellular cytoskeleton arrangement.
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Population genetic studies of freshwater invertebrate taxa in New Zealand and South America are currently few despite the geologically and climatically dynamic histories of these regions. The focus of our study was a comparison of the influence on realized dispersal of 2 closely related nonbiting midges (Chironomidae) of population fragmentation on these separated austral land masses. We used a 734-base pair (bp) fragment of cytochrome c oxidase subunit I (COI) to investigate intraspecific genetic structure in Naonella forsythi Boothroyd in New Zealand and Ferringtonia patagonica Edwards in Patagonia. We proposed hypotheses about their potential dispersal and, hence, expected patterns of genetic structure in these 2 species based on published patterns for the closely related Australian taxon Echinocladius martini Cranston. Genetic structure revealed for both N. forsythi and F. patagonica was characterized by several highly divergent (2.0–10.5%) lineages of late Miocene–Pliocene age within each taxon that were not geographically localized. Many were distributed widely. This pattern differed greatly from population structure in E. martini, which was typified by much greater endemicity of divergent genetic lineages. Nevertheless, diversification of lineages in all 3 taxa appeared to be temporally congruent with the onset of late Miocene glaciations in the southern hemisphere that may have driven fragmentation of suitable habitat, promoting isolation of populations and divergence in allopatry. We argue that differences in realized dispersal post-isolation may be the result of differing availability of suitable habitat in interglacial periods.
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Angiogenesis is indispensable for solid tumor expansion, and thus it has become a major target of cancer research and anti-cancer therapies. Deciphering the arcane actions of various cell populations during tumor angiogenesis requires sophisticated research models, which could capture the dynamics and complexity of the process. There is a continuous need for improvement of existing research models, which engages interdisciplinary approaches of tissue engineering with life sciences. Tireless efforts to develop a new model to study tumor angiogenesis result in innovative solutions, which bring us one step closer to decipher the dubious nature of cancer. This review aims to overview the recent developments, current limitations and future challenges in three-dimensional tissue-engineered models for the study of tumor angiogenesis and for the purpose of elucidating novel targets aimed at anti-cancer drug discovery.
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Closed WS2 nanoboxes were formed by topotactic sulfidization of a WO3/WO3 center dot 1/3H(2)O intergrowth precursor. Automated diffraction tomography was used to elucidate the growth mechanism of these unconventional hollow structures. By partial conversion and structural analysis of the products, each of them representing a snapshot of the reaction at a given point in time, the overall reaction can be broken down into a cascade of individual steps and each of them identified with a basic mechanism. During the initial step of sulfidization WO3 center dot 1/3H(2)O transforms into hexagonal WO3 whose surface allows for the epitaxial induction of WS2. The initially formed platelets of WS2 exhibit a preferred orientation with respect to the nanorod surface. In the final step individual layers of WS2 coalesce to form closed shells. In essence, a cascade of several topotactic reactions leads to epitactic induction and formation of closed rectangular hollow boxes made up from hexagonal layers.
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Heteroleptic complexes of the type \[RuL2L′](PF6)2 (L, L′ = combinations of 1,10-phenanthroline (phen) and 2,2′-bipyridine (bipy)) were found to cocrystallize with \[Ni(phen)3](PF6)2 to produce cocrystals of \[Ni(phen)3]x\[RuL2L′]1–x(PF6)2. In this report we show that the ability of the complexes to cocrystallize is influenced by the number of common ligands between complexes in solution. Supramolecular selection is a phenomenon caused by molecular recognition through which cocrystals can grow from the same solution but contain different ratios of the molecular components. It was found that systems where L = phen displayed less supramolecular selection than systems where L = bipy. With increasing supramolecular selection, the composition of cocrystals was found to vary significantly from the initial relative concentration in the cocrystallizing solution, and therefore it was increasingly difficult to control the final composition of the resultant cocrystals. Consequently, modulation of concentration-dependent properties such as phase was also found to be less predictable with increasing supramolecular selection. Notwithstanding the complication afforded by the presence of supramolecular selection, our results reaffirm the robustness of the \[M(phen)3](PF6)2 structure because it was maintained even when ca. 90% of the complexes in the cocrystals were \[Ru(phen)(bipy)2](PF6)2, which in its pure form is not isomorphous with \[M(phen)3](PF6)2. Experiments between complexes without common ligands, i.e., \[Ru(bipy)3](PF6)2 cocrystallized with \[Ni(phen)3](PF6)2, were found to approach the limit to which molecular recognition processes can be confused into cocrystallizing different molecules to form single cocrystals. For these systems the result was the formation of block-shaped crystals skewered by a needle-shaped crystals.
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Birds exhibit a huge array of behavior, ecology and physiology, and occupy nearly every environment on earth, ranging from the desert outback of Australia to the tropical rain forests of Panama. Some birds have adopted a fully nocturnal lifestyle, such as the barn owl and kiwi, while others, such as the albatross, spend nearly their entire life flying over the ocean. Each species has evolved unique adaptations over millions of years to function in their respective niche. In order to increase processing power or network efficiency, many of these adaptations require enlargements and/or specializations of the brain as a whole or of specific brain regions. In this study, we examine the relative size and morphology of 9 telencephalic regions in a number of Paleognath and Neognath birds and relate the findings to differences in behavior and sensory ecology. We pay particular attention to those species that have undergone a relative enlargement of the telencephalon to determine whether this relative increase in telencephalic size is homogeneous across different brain regions or whether particular regions have become differentially enlarged. The analysis indicates that changes in the relative size of telencephalic regions are not homogeneous, with every species showing hypertrophy or hypotrophy of at least one of them. The three-dimensional structure of these regions in different species was also variable, in particular that of the mesopallium in kiwi. The findings from this study provide further evidence that the changes in relative brain size in birds reflect a process of mosaic evolution.
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This study examines the effects of temporary tissue expanders (TTEs) on the dose distributions of photon beams in breast cancer radiotherapy treatments. EBT2 radiochromic film and ion chamber measurements were taken to quantify the attenuation and backscatter effects of the inhomogeneity. Results illustrate that the internal magnetic port present in a tissue expander causes a dose reduction of approximately 25% in photon tangent fields immediately downstream of the implant. It was also shown that the silicone elastomer shell of the tissue expander reduced the dose to the target volume by as much as 8%. This work demonstrates the importance for an accurately modelled high-density implant in the treatment planning system for post-mastectomy breast cancer patients.
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Aim Retinal tissue integrity in relation to diabetic neuropathy is not known. The aim of this study was to investigate retinal tissue thickness in relation to diabetic peripheral neuropathy (DPN) with and without diabetic retinopathy (DR). Methods Full retinal thickness at the parafoveal and perifoveal macula and neuro-retinal thickness around the optic nerve head (ONH) and at the macula was examined using spectral domain optical coherence tomography. The eye on the hand-dominant side of 85 individuals with type 1 diabetes and 66 individuals with type 2 diabetes, with or without DR and DPN, were compared to the eyes (n=45) of age-matched non-diabetic controls. Diabetic neuropathy was defined as Neuropathy Disability Score (NDS) ≥3 on a scale of 0-10. A general linear model was used to examine the relationship between diabetic neuropathy and foveal, parafoveal and perifoveal retinal thickness and neuro-retinal thickness, in relation to DR status, age, gender, HbA1c levels and duration of diabetes. A p-value of <0.05 was considered statistically significant. Results Perifoveal retinal thickness is reduced with increasing severity of neuropathy, especially in the inferior hemisphere (p=0.004); this effect was not related to age (p=0.088). For every unit increase in NDS score, the inferior perifoveal retinal thickness reduced by 1.64 μm. Neuro-retinal thickness around the ONH decreased with increasing severity of neuropathy (p<0.014 for average and hemisphere thicknesses); for every unit increase in NDS, neuro-retinal thickness around the ONH reduced by 1.23 μm. Retinal thickness in the parafovea was increased in the absence of DR (p<0.017 for average and hemisphere thicknesses). Neuro-retinal thickness at the macula was inversely related to age alone (p<0.001). All retinal parameters, except the inferior perifovea, reduced with advancing age (p<0.007 for all). Conclusions Diabetic neuropathy is associated with changes in full retinal thickness and neuro-retinal layers. This may represent a second threat to vision integrity, in addition to the better-characterised retinopathy. This study provides new knowledge about the anatomical aspects of the retinal tissue in relation to neuropathy and retinopathy.