Measurement of optical to electrical and electrical to optical delays with ps-level uncertainty

We present a new measurement principle to determine the absolute time delay of a waveform from an optical reference plane to an electrical reference plane and vice versa. We demonstrate a method based on this principle with 2 ps uncertainty. This method can be used to perform accurate time delay determinations of optical transceivers used in fibre-optic time-dissemination equipment. As a result the time scales in optical and electrical domain can be related to each other with the same uncertainty. We expect this method to break new grounds in high-accuracy time transfer and absolute calibration of time-transfer equipment

The murine male reproductive organ at a glance: Three-dimensional insights and virtual histology using label-free light sheet microcopy

Background:The unique anatomy of the male reproductive organ reflects its complex function from sperm maturation to their storage for months until emission. Since light microscopy in two dimensions (2d) cannot sufficiently demonstrate its complex morphology, a comprehensive visualization is required to identify pathologic alterations in its entire anatomical context.Objectives:Aim of this study was to use three-dimensional (3d) light sheet fluorescence microscopy (LSFM) to visualize entire murine testes in 3d, label-free and at subcellular resolution, and to assign local autofluorescence to testicular and deferent structures.Materials and methods:Murine testes were fixed with four different fixatives and subsequently cleared with benzoic acid/benzyl benzoate. Hereafter, complete murine testes were scanned with LSFM with different fluorescence filter sets and subsequently embedded in paraffin for further conventional planar histology.Results:Autofluorescence signals of the murine reproductive organ allowed the unambiguous identification of the testicular anatomy from the seminiferous tubules to the vas deferens with their specific stratification independent of the used fixative. Blood vessels were visualized from the pampiniform plexus to the small capillaries of single tubules. Moreover, due to the specific intrinsic fluorescence properties of the efferent ducts and the epididymis, luminal caliber, the epithelial stratification and retronuclear cytoplasmic inclusions gave a unique insight into the interface of both morphological structures. Subsequent 2d histology confirmed the identified morphological structures.Discussion:LSFM analysis of the murine reproductive organ allows due to its intrinsic fluorescence a simple, label-free 3d assessment of its entire duct morphology, the epithelial composition, and the associated blood supply in its anatomical relation.Conclusion:LSFM provides the technical basis for comprehensive analyses of pathologically altered murine testes in its entirety by depicting specific autofluorescence. Thereby it facilitates mouse studies of testicular disease or their drug-related alterations in more detail potentially for clinical translation assessing human testicular biopsies.<br

3D virtual histology of murine kidneys-high resolution visualization of pathological alterations by micro computed tomography

The increasing number of patients with end stage chronic kidney disease not only calls for novel therapeutics but also for pioneering research using convincing preclinical disease models and innovative analytical techniques. The aim of this study was to introduce a virtual histology approach using micro computed tomography (mu CT) for the entire murine kidney in order to close the gap between single slice planar histology and a 3D high resolution dataset. An ex vivo staining protocol based on phosphotungstic acid diffusion was adapted to enhance renal soft tissue x-ray attenuation. Subsequent CT scans allowed (i) the detection of the renal cortex, medulla and pelvis in greater detail, (ii) the analysis of morphological alterations, (iii) the quantification of the volume as well as the radio-opacity of these portions and (iv) the quantification of renal fibrotic remodeling based on altered radio-opacity using the unilateral ureteral obstruction model. Thus, virtual histology based on PTA contrast enhanced CT will in future help to refine the outcome of preclinical research on kidney associated murine disease models

Widespread Proteome Remodeling and Aggregation in Aging C-elegans

Aging has been associated with a progressive decline of proteostasis, but how this process affects proteome composition remains largely unexplored. Here, we profiled more than 5,000 proteins along the lifespan of the nematode C. elegans. We find that one-third of proteins change in abundance at least 2-fold during aging, resulting in a severe proteome imbalance. These changes are reduced in the long-lived daf-2 mutant but are enhanced in the short-lived daf-16 mutant. While ribosomal proteins decline and lose normal stoichiometry, proteasome complexes increase. Proteome imbalance is accompanied by widespread protein aggregation, with abundant proteins that exceed solubility contributing most to aggregate load. Notably, the properties by which proteins are selected for aggregation differ in the daf-2 mutant, and an increased formation of aggregates associated with small heat-shock proteins is observed. We suggest that sequestering proteins into chaperone-enriched aggregates is a protective strategy to slow proteostasis decline during nematode aging

Amyloid-like aggregates sequester numerous metastable proteins with essential cellular functions

Protein aggregation is linked with neurodegeneration and numerous other diseases by mechanisms that are not well understood. Here, we have analyzed the gain-of-function toxicity of artificial β sheet proteins that were designed to form amyloid-like fibrils. Using quantitative proteomics, we found that the toxicity of these proteins in human cells correlates with the capacity of their aggregates to promote aberrant protein interactions and to deregulate the cytosolic stress response. The endogenous proteins that are sequestered by the aggregates share distinct physicochemical properties: They are relatively large in size and significantly enriched in predicted unstructured regions, features that are strongly linked with multifunctionality. Many of the interacting proteins occupy essential hub positions in cellular protein networks, with key roles in chromatin organization, transcription, translation, maintenance of cell architecture and protein quality control. We suggest that amyloidogenic aggregation targets a metastable subproteome, thereby causing multifactorial toxicity and, eventually, the collapse of essential cellular functions. PaperFlick: © 2011 Elsevier Inc

Identification of Colletotrichum species associated with anthracnose disease of coffee in Vietnam

Colletotrichum gloeosporioides, C. acutatum, C. capsici and C. boninense associated with anthracnose disease on coffee (Coffea spp.) in Vietnam were identified based on morphology and DNA analysis. Phylogenetic analysis of DNA sequences from the internal transcribed spacer region of nuclear rDNA and a portion of mitochondrial small subunit rRNA were concordant and allowed good separation of the taxa. We found several Colletotrichum isolates of unknown species and their taxonomic position remains unresolved. The majority of Vietnamese isolates belonged to C. gloeosporioides and they grouped together with the coffee berry disease (CBD) fungus, C. kahawae. However, C. kahawae could be distinguished from the Vietnamese C. gloeosporioides isolates based on ammonium tartrate utilization, growth rate and pathogenictity. C. gloeosporioides isolates were more pathogenic on detached green berries than isolates of the other species, i.e. C. acutatum, C capsici and C. boninense. Some of the C. gloeosporioides isolates produced slightly sunken lesion on green berries resembling CBD symptoms but it did not destroy the bean. We did not find any evidence of the presence of C. kahawae in Vietnam

Effective generation of transgenic pigs and mice by linker based sperm-mediated gene transfer.

BACKGROUND: Transgenic animals have become valuable tools for both research and applied purposes. The current method of gene transfer, microinjection, which is widely used in transgenic mouse production, has only had limited success in producing transgenic animals of larger or higher species. Here, we report a linker based sperm-mediated gene transfer method (LB-SMGT) that greatly improves the production efficiency of large transgenic animals. RESULTS: The linker protein, a monoclonal antibody (mAb C), is reactive to a surface antigen on sperm of all tested species including pig, mouse, chicken, cow, goat, sheep, and human. mAb C is a basic protein that binds to DNA through ionic interaction allowing exogenous DNA to be linked specifically to sperm. After fertilization of the egg, the DNA is shown to be successfully integrated into the genome of viable pig and mouse offspring with germ-line transfer to the F1 generation at a highly efficient rate: 37.5% of pigs and 33% of mice. The integration is demonstrated again by FISH analysis and F2 transmission in pigs. Furthermore, expression of the transgene is demonstrated in 61% (35/57) of transgenic pigs (F0 generation). CONCLUSIONS: Our data suggests that LB-SMGT could be used to generate transgenic animals efficiently in many different species

Determination of the in vivo structural DNA loop organization in the genomic region of the rat albumin locus by means of a topological approach

Nuclear DNA of metazoans is organized in supercoiled loops anchored to a proteinaceous substructure known as the nuclear matrix (NM). DNA is anchored to the NM by non-coding sequences known as matrix attachment regions (MARs). There are no consensus sequences for identification of MARs and not all potential MARs are actually bound to the NM constituting loop attachment regions (LARs). Fundamental processes of nuclear physiology occur at macromolecular complexes organized on the NM; thus, the topological organization of DNA loops must be important. Here, we describe a general method for determining the structural DNA loop organization in any large genomic region with a known sequence. The method exploits the topological properties of loop DNA attached to the NM and elementary topological principles such as that points in a deformable string (DNA) can be positionally mapped relative to a position-reference invariant (NM), and from such mapping, the configuration of the string in third dimension can be deduced. Therefore, it is possible to determine the specific DNA loop configuration without previous characterization of the LARs involved. We determined in hepatocytes and B-lymphocytes of the rat the DNA loop organization of a genomic region that contains four members of the albumin gene family

Human Cardiac-Derived Adherent Proliferating Cells Reduce Murine Acute Coxsackievirus B3-Induced Myocarditis

BACKGROUND: Under conventional heart failure therapy, inflammatory cardiomyopathy typically has a progressive course, indicating a need for alternative therapeutic strategies to improve long-term outcomes. We recently isolated and identified novel cardiac-derived cells from human cardiac biopsies: cardiac-derived adherent proliferating cells (CAPs). They have similarities with mesenchymal stromal cells, which are known for their anti-apoptotic and immunomodulatory properties. We explored whether CAPs application could be a novel strategy to improve acute Coxsackievirus B3 (CVB3)-induced myocarditis. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the safety of our approach, we first analyzed the expression of the coxsackie- and adenovirus receptor (CAR) and the co-receptor CD55 on CAPs, which are both required for effective CVB3 infectivity. We could demonstrate that CAPs only minimally express both receptors, which translates to minimal CVB3 copy numbers, and without viral particle release after CVB3 infection. Co-culture of CAPs with CVB3-infected HL-1 cardiomyocytes resulted in a reduction of CVB3-induced HL-1 apoptosis and viral progeny release. In addition, CAPs reduced CD4 and CD8 T cell proliferation. All CAPs-mediated protective effects were nitric oxide- and interleukin-10-dependent and required interferon-γ. In an acute murine model of CVB3-induced myocarditis, application of CAPs led to a decrease of cardiac apoptosis, cardiac CVB3 viral load and improved left ventricular contractility parameters. This was associated with a decline in cardiac mononuclear cell activity, an increase in T regulatory cells and T cell apoptosis, and an increase in left ventricular interleukin-10 and interferon-γ mRNA expression. CONCLUSIONS: We conclude that CAPs are a unique type of cardiac-derived cells and promising tools to improve acute CVB3-induced myocarditis