Microstructure and mineral composition of dystrophic calcification associated with the idiopathic inflammatory myopathies

Introduction  

Calcified deposits (CDs) in skin and muscles are common in juvenile dermatomyositis (DM), and less frequent in adult DM. Limited information exists about the microstructure and composition of these deposits, and no information is available on their elemental composition and contents, mineral density (MD) and stiffness. We determined the microstructure, chemical composition, MD and stiffness of CDs obtained from DM patients.     

Evidence that the phytochrome gene family in black cottonwood has one PHYA locus and two PHYB loci but lacks members of the PHYC/F and PHYE subfamilies

The phytochrome photoreceptors play important roles in the photoperiodic control of vegetative bud set, growth cessation, dormancy induction, and cold-hardiness in trees. Interestingly, ecotypic differences in photoperiodic responses are observed in many temperate- zone tree species. Northern and southern ecotypes of black cottonwood (Populus trichocarpa Torr. & Gray), for example, exhibit marked differences in the timing of short-day-induced bud set and growth cessation, and these responses are controlled by phytochrome. Therefore, as a first step toward determining the molecular genetic basis of photoperiodic ecotypes in trees, we characterized the phytochrome gene (PHY) family in black cottonwood. We recovered fragments of one PHYA and two PHYB using PCR-based cloning and by screening a genomic library. Results from Southern analyses confirmed that black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum) suggest that the PHYB/D duplications in these species occurred independently. When Southern blots were probed with PHYC, PHYE, and PHYE heterologous probes, the strongest bands that we detected were those of black cottonwood PHYA and/or PHYB. These results suggest that black cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black cottonwood could contain additional PHY that are distantly related to known angiosperm PHY, our results imply that the PHY family of black cottonwood is less complex than that of other well-characterized dicot species such as Arabidopsis and tomato. Based on Southern analyses of five black cottonwood genotypes representing three photoperiodic ecotypes, substantial polymorphism was detected for at least one of the PHYB loci but not for the PHYA locus. The novel character of the PHY family in black cottonwood, as well as the differences in polymorphism we observed between the PHYA and PHYB subfamilies, indicates that a number of fundamental macro- and microevolutionary questions remain to be answered about the PHY family in dicots.      

Pectic homogalacturonan masks abundant sets of xyloglucan epitopes in plant cell walls

Background  

Molecular probes are required to detect cell wall polymers in-situ to aid understanding of their cell biology and several studies have shown that cell wall epitopes have restricted occurrences across sections of plant organs indicating that cell wall structure is highly developmentally regulated. Xyloglucan is the major hemicellulose or cross-linking glycan of the primary cell walls of dicotyledons although little is known of its occurrence or functions in relation to cell development and cell wall microstructure.     

Characterization of a maltose transport system in Clostridium acetobutylicum ATCC 824

The utilization of maltose by Clostridium acetobutylicum ATCC 824 was investigated. Glucose was used preferentially to maltose, when both substrates were present in the medium. Maltose phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) activity was detected in extracts prepared from cultures grown on maltose, but not glucose or sucrose, as the sole carbon source. Extract fractionation and PTS reconstitution experiments revealed that the specificity for maltose is contained entirely within the membrane in this organism. A putative gene system for the maltose PTS was identified (from the C. acetobutylicum ATCC 824 genome sequence), encoding an enzyme II^Mal and a maltose 6-phosphate hydrolase. Journal of Industrial Microbiology & Biotechnology (2001) 27, 298–306. Received 12 September 2000/ Accepted in revised form 30 November 2000     

Distinct ex vivo susceptibility of B-cell subsets to epstein-barr virus infection according to differentiation status and tissue origin

Epstein-Barr virus (EBV) uses tonsils as the portal of entry to establish persistent infection. EBV is found in various B-cell subsets in tonsils but exclusively in memory B cells in peripheral blood. The in vitro susceptibilities of B-cell subsets to EBV infection have been studied solely qualitatively. In this work, we examined quantitatively the in vitro susceptibilities of various B-cell subsets from different tissue origins to EBV infection. First, we established a centrifugation-based inoculation protocol (spinoculation) that resulted in a significantly increased proportion of infected cells compared to that obtained by conventional inoculation, enabling a detailed susceptibility analysis. Importantly, B-cell infection occurred via the known EBV receptors and infected cells showed EBV mRNA expression patterns similar to those observed after conventional inoculation, validating our approach. Tonsillar na?ve and memory B cells were infected ex vivo at similar frequencies. In contrast, memory B cells from blood, which represent B cells from various lymphoid tissues, were infected at lower frequencies than their na?ve counterparts. Immunoglobulin A (IgA)-positive or IgG-positive tonsillar memory B cells were significantly more susceptible to EBV infection than IgM-positive counterparts. Memory B cells were transformed with lower efficiency than na?ve B cells. This result was paralleled by lower proliferation rates. In summary, these data suggest that EBV exploits the B-cell differentiation status and tissue origin to establish persistent infection.     

Genetic and molecular in vivo analysis of herpes simplex virus assembly in murine visual system neurons

Herpes simplex virus (HSV) infects both epithelial cells and neuronal cells of the human host. Although HSV assembly has been studied extensively for cultured epithelial and neuronal cells, cultured neurons are biochemically, physiologically, and anatomically significantly different than mature neurons in vivo. Therefore, it is imperative that viral maturation and assembly be studied in vivo. To study viral assembly in vivo, we inoculated wild-type and replication-defective viruses into the posterior chamber of mouse eyes and followed infection in retinal ganglion cell bodies and axons. We used PCR techniques to detect viral DNA and RNA and electron microscopy immunohistochemistry and Western blotting to detect viral proteins in specific portions of the optic tract. This approach has shown that viral DNA replication is necessary for viral DNA movement into axons. Movement of viral DNA along ganglion cell axons occurs within capsid-like structures at the speed of fast axonal transport. These studies show that the combined use of intravitreal injections of replication-defective viruses and molecular probes allows the genetic analysis of essential viral replication and maturation processes in neurons in vivo. The studies also provide novel direct evidence for the axonal transport of viral DNA and support for the subassembly hypothesis of viral maturation in situ.