Quaternary TDM-PAM as upgrade path of access PON beyond 10Gb/s

A 20 Gb/s quaternary TDM-PAM passive optical network with chirped and non-linear optical transmitters is experimentally demonstrated. The migration from legacy TDM-PONs and the implications of using available 10 Gb/s components are analyzed. We show that a loss budget of 27.3 dB is compatible together with a packet power ratio of 10 dB between loud and soft optical network units. (c) 2012 Optical Society of Americ

New Approach for M-Cell-Specific Molecules Screening by Comprehensive Transcriptome Analysis

A minor population of M cells within the follicle-associated epithelium (FAE) of intestinal Peyer's patches (PPs) serves as a major portal for entry of exogenous antigens. Characterization of the mammalian M cells, including identification of M-cell surface molecules used for bacterial uptake, has been hampered by their relative rarity. In contrast, M cells constitute virtually all of the FAE cells in the avian bursa of Fabricius. We therefore performed comparative gene expression profiling of chicken and murine FAE to identify commonly expressed genes by M cells in both species. The comprehensive transcriptome analysis revealed that 28 genes were commonly up-regulated in FAE from both species. In situ hybridization revealed that annexin A10 (Anxa10) mRNA was scattered in FAE, and co-localized with Ulex europaeus agglutinin-1 binding to M cells. Whole-mount immunostaining also revealed that cellular prion protein (PrPC) was expressed on the luminal side of the apical plasma membrane of M cells, and co-localized with grycoprotein 2 that recognizes only M cells in murine PP. Our findings identify new M-cell-specific molecules through using comprehensive transcriptome analysis. These conserved molecules in M cells of mice and chickens may play essential roles in M-cell function and/or differentiation

Identification of Novel Genes Selectively Expressed in the Follicle-Associated Epithelium from the Meta-Analysis of Transcriptomics Data from Multiple Mouse Cell and Tissue Populations

The follicle-associated epithelium (FAE) overlying the Peyer’s patches and the microfold cells (M cells) within it are important sites of antigen transcytosis across the intestinal epithelium. Using a meta-analysis approach, we identified a transcriptional signature that distinguished the FAE from a large collection of mouse cells and tissues. A co-expressed cluster of 21 FAE-specific genes was identified, and the analysis of the transcription factor binding site motifs in their promoter regions indicated that these genes shared an underlying transcriptional programme. This cluster contained known FAE- (Anxa10, Ccl20, Psg18 and Ubd) and M-cell-specific (Gp2) genes, suggesting that the others were novel FAE-specific genes. Some of these novel candidate genes were expressed highly by the FAE and M cells (Calcb, Ces3b, Clca2 and Gjb2), and others only by the FAE (Ascl2, Cftr, Fgf15, Gpr133, Kcna1, Kcnj15,Mycl1, Pgap1 and Rps6kl). We also identified a subset of novel FAE-related genes that were induced in the intestinal epithelium after receptor activatorof nuclear factor (NF)-kB ligand stimulation. These includedMfge8whichwas specific to FAE enter-ocytes. This studyprovides new insight into the FAE transcriptome. Furthercharacterizationof the candidate genes identified here will aid the identification of novel regulators of cell function in the FAE

The chromosomal passenger complex and centralspindlin independently contribute to contractile ring assembly

In contrast to their sequential roles in midzone assembly, the CPC and centralspindlin act through independent mechanisms to regulate contractile ring assembly

Comparison of the fecal microbiota of adult healthy dogs fed a plant-based (vegan) or an animal-based diet

PurposePet guardians are increasingly seeking vegan dog foods. However, research on the impact of these diets on gastrointestinal (GI) physiology and health is limited. In humans, vegan diets modify the GI microbiota, increasing beneficial digestive microorganisms. This study aimed to examine the canine fecal microbiota in response to a vegan diet compared to an animal-based diet.MethodsSixty-one client-owned healthy adult dogs completed a randomized, double-blinded longitudinal study. Dogs were randomly assigned into two groups that were fed either a commercial extruded animal-based diet (MEAT, n = 30) or an experimental extruded vegan diet (PLANT, n = 31) for 12 weeks. Fecal collections occurred at the start of the experimental period and after 3 months of exclusively feeding either diet. Bacterial DNA was extracted from the feces, and the V4 region of the 16S rRNA gene was amplified using PCR and sequenced on Illumina MiSeq. Beta-diversity was measured using Jaccard and Bray–Curtis distances, and the PERMANOVA was used to assess for differences in fecal microbiota within and between groups. Alpha-diversity indices for richness, evenness, and diversity, as well as relative abundance, were calculated and compared between groups.ResultsBeta-diversity differences occurred between diet groups at exit time-point with differences on Bray–Curtis distances at the family and genus levels (p = 0.007 and p = 0.001, respectively), and for the Jaccard distance at the family and genus level (p = 0.006 and p = 0.011, respectively). Significant differences in alpha-diversity occurred when comparing the PLANT to the MEAT group at the exit time-point with the PLANT group having a lower evenness (p = 0.012), but no significant differences in richness (p = 0.188), or diversity (p = 0.06). At exit-timepoint, compared to the MEAT group, the relative abundance of Fusobacterium, Bacteroides, and Campylobacter was lower in the PLANT group. The relative abundance of Fusobacterium decreased over time in the PLANT group, while no change was observed in the MEAT group.ConclusionThese results indicate that vegan diets may change the canine gut microbiota. Future studies are warranted to confirm our results and determine long-term effects of vegan diets on the canine gut microbiome

LET-99 inhibits lateral posterior pulling forces during asymmetric spindle elongation in C. elegans embryos

GPR-1/2 (regulators of Gα signaling necessary for asymmetric cell division) receives a positional cue from Let-99, resulting in its appropriate distribution around the posterior cortex

RefGenes: identification of reliable and condition specific reference genes for RT-qPCR data normalization

Background RT-qPCR is a sensitive and increasingly used method for gene expression quantification. To normalize RT-qPCR measurements between samples, most laboratories use endogenous reference genes as internal controls. There is increasing evidence, however, that the expression of commonly used reference genes can vary significantly in certain contexts. Results Using the Genevestigator database of normalized and well-annotated microarray experiments, we describe the expression stability characteristics of the transciptomes of several organisms. The results show that a) no genes are universally stable, b) most commonly used reference genes yield very high transcript abundances as compared to the entire transcriptome, and c) for each biological context a subset of stable genes exists that has smaller variance than commonly used reference genes or genes that were selected for their stability across all conditions. Conclusion We therefore propose the normalization of RT-qPCR data using reference genes that are specifically chosen for the conditions under study. RefGenes is a community tool developed for that purpose. Validation RT-qPCR experiments across several organisms showed that the candidates proposed by RefGenes generally outperformed commonly used reference genes. RefGenes is available within Genevestigator at http://www.genevestigator.com

The functional maturation of M cells is dramatically reduced in the Peyer's patches of aged mice

The transcytosis of antigens across the follicle-associated epithelium (FAE) of Peyer's patches by microfold cells (M cells) is important for the induction of efficient immune responses to mucosal antigens. The mucosal immune response is compromised by ageing, but effects on M cells were unknown. We show that M-cell density in the FAE of aged mice was dramatically reduced. As a consequence, aged Peyer's patches were significantly deficient in their ability to transcytose particulate lumenal antigen across the FAE. Ageing specifically impaired the expression of Spi-B and the downstream functional maturation of M cells. Ageing also dramatically impaired C-C motif chemokine ligand 20 expression by the FAE. As a consequence, fewer B cells were attracted towards the FAE, potentially reducing their ability to promote M-cell maturation. Our study demonstrates that ageing dramatically impedes the functional maturation of M cells, revealing an important ageing-related defect in the mucosal immune system's ability to sample lumenal antigens

Towards sustainable polymeric nano-carriers and surfactants: facile low temperature enzymatic synthesis of bio-based amphiphilic copolymers in scCO2

We demonstrate that useful bio-based amphiphilic polymers can be produced enzymatically at a mild temperature, in a solvent-free system and using renewably sourced monomers, by exploiting the unique properties of supercritical CO2 (scCO2). We present the use of a novel near-ambient temperature approach to prepare renewable amphiphilic ABA copolymers in scCO2. Bio-based commercially available monomers have been polymerised to prepare chains with targeted molecular weight. The amphiphilic materials were prepared by end-capping the synthesised polymers with methoxy poly(ethylene glycol) (MPEG) chains in a one-pot high pressure reaction utilising Candida Antarctica Lipase B (CaLB) as a catalyst at a temperature as low as 35 °C. The block copolymers are characterised by 1H-NMR, GPC and DSC in order to carefully assess their structural and thermal properties. These polymers form self-assembled aggregates in aqueous environment and these nanostructures are studied through DLS, TEM and UV-Vis. Highly hydrophobic Coumarin-6 was used as a model to prove dispersion in water of lipophilic molecules. Maximum bubble pressure tests demonstrate the reduction in surface tension of these polymers and comparisons are made directly to commercial polymeric non-ionic surfactants