Exposure of Bifidobacterium longum subsp. infantis to Milk Oligosaccharides Increases Adhesion to Epithelial Cells and Induces a Substantial Transcriptional Response

Devon Kavanaugh is in receipt of a Teagasc Walsh Fellowship. The authors would also like to acknowledge the support of Science Foundation Ireland under Grant No. 08/SRC/B1393 and the Alimentary Glycoscience Research Cluster (AGRC).peer-reviewedIn this study, we tested the hypothesis that milk oligosaccharides may contribute not only to selective growth of bifidobacteria, but also to their specific adhesive ability. Human milk oligosaccharides (3′sialyllactose and 6′sialyllactose) and a commercial prebiotic (Beneo Orafti P95; oligofructose) were assayed for their ability to promote adhesion of Bifidobacterium longum subsp. infantis ATCC 15697 to HT-29 and Caco-2 human intestinal cells. Treatment with the commercial prebiotic or 3′sialyllactose did not enhance adhesion. However, treatment with 6′sialyllactose resulted in increased adhesion (4.7 fold), while treatment with a mixture of 3′- and 6′-sialyllactose substantially increased adhesion (9.8 fold) to HT-29 intestinal cells. Microarray analyses were subsequently employed to investigate the transcriptional response of B. longum subsp. infantis to the different oligosaccharide treatments. This data correlated strongly with the observed changes in adhesion to HT-29 cells. The combination of 3′- and 6′-sialyllactose resulted in the greatest response at the genetic level (both in diversity and magnitude) followed by 6′sialyllactose, and 3′sialyllactose alone. The microarray data was further validated by means of real-time PCR. The current findings suggest that the increased adherence phenotype of Bifidobacterium longum subsp. infantis resulting from exposure to milk oligosaccharides is multi-faceted, involving transcription factors, chaperone proteins, adhesion-related proteins, and a glycoside hydrolase. This study gives additional insight into the role of milk oligosaccharides within the human intestine and the molecular mechanisms underpinning host-microbe interactions.Science Foundation IrelandTeagasc Walsh Fellowship Programm

Bovine glycomacropeptide promotes the growth of Bifidobacterium longum ssp. infantis and modulates its gene expression

peer-reviewedBovine milk glycomacropeptide (GMP) is derived from κ-casein, with exclusively o-linked glycosylation. Glycomacropeptide promoted the growth of Bifidobacterium longum ssp. infantis in a concentration-dependent manner, and this activity was lost following periodate treatment of the GMP (GMP-P), which disables biological recognition of the conjugated oligosaccharides. Transcriptional analysis of B. longum ssp. infantis following exposure to GMP revealed a substantial response to GMP relative to bacteria treated with GMP-P, with a greater number of differentially expressed transcripts and larger fold changes versus the control. Therefore, stimulation of B. longum ssp. infantis growth by GMP is intrinsically linked to the peptide's O-linked glycosylation. The pool of differentially expressed transcripts included 2 glycoside hydrolase (family 25) genes, which were substantially upregulated following exposure to GMP, but not GMP-P. These GH25 genes were present in duplicated genomic islands that also contained genes encoding fibronectin type III binding domain proteins and numerous phage-related proteins, all of which were also upregulated. Homologs of this genomic arrangement were present in other Bifidobacterium species, which suggest it may be a conserved domain for the utilization of glycosylated peptides. This study provides insights into the molecular basis for the prebiotic effect of bovine milk GMP on B. longum ssp. infantis

Desarrollo de fibras de PLA con elevada resistencia y rigidez por estirado en estado sólido

La mayor parte de los plásticos utilizados en la actualidad provienen de recursos no renovables y no son biodegradables. Si al final de su vida útil no se dispone de ellos adecuadamente, tienden a acumularse en el ambiente y pueden causar graves daños a los ecosistemas. En las últimas décadas se ha comenzado a generar conciencia sobre este impacto negativo, por lo que ha cobrado gran relevancia el desarrollo de materiales sustentables, que provengan de fuentes renovables y que permitan una disposición finalamigable con el medio ambiente, entre los que se destaca el ácido poliláctico (PLA). Este polímero termoplástico puede procesarse con las técnicas de conformado convencionales de plásticos para producir films, láminas, botellas e incluso fibras. En particular, es de gran interés el desarrollo de fibras de elevada resistencia y rigidez que pueden ser utilizadas en la industria textil o como material de refuerzo en compuestos para múltiples aplicaciones. Una de las técnicas más utilizadas para este fin es la de estirado en estado sólido de filamentos extruidos, que consiste en estirar el material cuando se encuentra entre la temperatura de transición vítrea y la de fusión. Esto genera una reducción en el diámetro y un reordenamiento a nivel molecular, que mejora sus propiedades mecánicas. En este trabajo se estiraron filamentos de PLA comerciales para impresión 3D variando las condiciones de procesamiento (temperatura y velocidad de estirado). Independientemente de dichas condiciones se obtuvieron fibras significativamente más rígidas y resistentes que los filamentos de partida.Fil: Butto, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Maspoch, M. L l.. Universidad Politécnica de Catalunya; EspañaFil: Bernal, Celina Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina5° Congreso Argentino de Ingeniería; 11° Congreso Argentino de Enseñanza de la Ingeniería y 3° Congreso Latinoamericano de IngenieríaBuenos AiresArgentinaConsejo Federal de Decanos de Ingeniería de la República ArgentinaUniversidad de Buenos Aires. Facultad de Ingenierí

Desarrollo de fibras de ácido poliláctico de elevada prestación mecánica

Existe un gran interés en el desarrollo de fibras poliméricas de elevada resistencia y rigidez para aplicaciones en la industria textil o como refuerzo en materiales compuestos, entre otras. En particular, las fibras de ácido poliláctico (PLA) resultan muy atractivas debido a que este polímero proviene de fuentes renovables, es reciclable, biocompatible y presenta propiedades mecánicas comparables a las de muchos plásticos convencionales. En este trabajo se empleó la técnica de estirado en estado sólido, una de las más utilizadas a nivel industrial, para producir fibras a partir de filamentos extruidos de distinto diámetro y obtenidos a partir de diferentes resinas (Ingeo™ 3D850 e Ingeo™ 4043D). El estirado provocó un cambio en el comportamiento mecánico del material, obteniéndose fibras más rígidas, resistentes y tenaces que los filamentos de partida. La variación de la temperatura de procesamiento no tuvo un efecto significativo sobre las propiedades finales de las fibras.Fil: Butto, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Maspoch Rulduà, M. L l.. Universidad Politécnica de Catalunya; EspañaFil: Bernal, Celina Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaXVI Simposio Argentino de PolímerosBahía BlancaArgentinaPlanta Piloto de Ingeniería QuímicaUniversidad Nacional del Su

Giant pulmonary artery aneurysm in a patient with vasoreactive pulmonary hypertension: a case report

<p>Abstract</p> <p>Background</p> <p>Pulmonary artery aneurysms are a rare condition, frequently associated with pulmonary hypertension. However, the evolution and treatment of this pathology is still not clear.</p> <p>Case Presentation</p> <p>The authors report a case of a 65-year old patient with pulmonary artery aneurysm associated with pulmonary arterial hypertension. Due to a positive vasoreactivity test, treatment with calcium channel blockers was started with near normalization of the right cardiac pressures. Nevertheless, after 20 months of treatment, the pulmonary artery aneurysm size remained unchanged with an associated severe pulmonary regurgitation and causing extrinsic compression of the main left coronary artery. Surgical correction was successfully performed.</p> <p>Conclusions</p> <p>This is the first case report of a pulmonary artery aneurysm described to be associated with vasoreactive pulmonary hypertension in a living patient. Although medical therapy for pulmonary hypertension was started, surgical correction of the aneurysm was executed in order to prevent its future complications.</p

Isothermal Amplification Using a Chemical Heating Device for Point-of-Care Detection of HIV-1

Background: To date, the use of traditional nucleic acid amplification tests (NAAT) for detection of HIV-1 DNA or RNA has been restricted to laboratory settings due to time, equipment, and technical expertise requirements. The availability of a rapid NAAT with applicability for resource-limited or point-of-care (POC) settings would fill a great need in HIV diagnostics, allowing for timely diagnosis or confirmation of infection status, as well as facilitating the diagnosis of acute infection, screening and evaluation of infants born to HIV-infected mothers. Isothermal amplification methods, such as reversetranscription, loop-mediated isothermal amplification (RT-LAMP), exhibit characteristics that are ideal for POC settings, since they are typically quicker, easier to perform, and allow for integration into low-tech, portable heating devices. Methodology/Significant Findings: In this study, we evaluated the HIV-1 RT-LAMP assay using portable, non-instrumented nucleic acid amplification (NINA) heating devices that generate heat from the exothermic reaction of calcium oxide and water. The NINA heating devices exhibited stable temperatures throughout the amplification reaction and consistent amplification results between three separate devices and a thermalcycler. The performance of the NINA heaters was validated using whole blood specimens from HIV-1 infected patients. Conclusion: The RT-LAMP isothermal amplification method used in conjunction with a chemical heating device provides

Elevated apoptosis impairs epithelial cell turnover and shortens villi in TNF-driven intestinal inflammation

The intestinal epithelial monolayer, at the boundary between microbes and the host immune system, plays an important role in the development of inflammatory bowel disease (IBD), particularly as a target and producer of pro-inflammatory TNF. Chronic overexpression of TNF leads to IBD-like pathology over time, but the mechanisms driving early pathogenesis events are not clear. We studied the epithelial response to inflammation by combining mathematical models with in vivo experimental models resembling acute and chronic TNF-mediated injury. We found significant villus atrophy with increased epithelial cell death along the crypt-villus axis, most dramatically at the villus tips, in both acute and chronic inflammation. In the acute model, we observed overexpression of TNF receptor I in the villus tip rapidly after TNF injection and concurrent with elevated levels of intracellular TNF and rapid shedding at the tip. In the chronic model, sustained villus atrophy was accompanied by a reduction in absolute epithelial cell turnover. Mathematical modelling demonstrated that increased cell apoptosis on the villus body explains the reduction in epithelial cell turnover along the crypt-villus axis observed in chronic inflammation. Cell destruction in the villus was not accompanied by changes in proliferative cell number or division rate within the crypt. Epithelial morphology and immunological changes in the chronic setting suggest a repair response to cell damage although the villus length is not recovered. A better understanding of how this state is further destabilised and results in clinical pathology resembling IBD will help identify suitable pathways for therapeutic intervention

A mathematical model for IP over ATM

We consider IP over ATM networking scenario, widely deployed today, where Asynchronous Transfer Mode (ATM) is used as a backbone network to provide high-speed transport for the Internet Protocol (IP) traffic. Telecommunication network carriers and Internet Service Providers (ISPs), that have deployed ATM as their backbone networks, need to model and characterize the IP traffic in order to plan and manage these networks to meet specified performance measures demanded by their customers. This paper addresses the problem of modelling IP traffic that is being transported over links of an ATM network. It provides mathematical models that can be used to take measurement data and translate it into a form that is suitable for various planning and management functions performed by network carriers