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     

The siRNA sequence and guide strand overhangs are determinants of in vivo duration of silencing

The use of short interfering RNAs (siRNA) in animals for target validation or as potential therapeutics is hindered by the short physical half-life when delivered as unencapsulated material and in turn the short active half-life of siRNAs in vivo. Here we demonstrate that the character of the two 3′-overhang nucleotides of the guide strand of siRNAs is a determinant of the duration of silencing by siRNAs both in vivo and in tissue culture cells. We demonstrate that deoxyribonucleotides in the guide strand overhang of siRNAs have a negative impact on maintenance of both the in vitro and in vivo activity of siRNAs over time. Overhangs that contain ribonucleotides or 2′-O-methyl modified nucleotides do not demonstrate this same impairment. We also demonstrate that the sequence of an siRNA is a determinant of the duration of silencing of siRNAs directed against the same target even when those siRNAs have equivalent activities in vitro. Our experiments have determined that a measurable duration parameter exists, distinct from both maximum silencing ability and the potency of siRNAs. Our findings provide information on incorporating chemically modified nucleotides into siRNAs for potent, durable therapeutics and also inform on methods used to select siRNAs for therapeutic and research purposes.     

Management of Fusarium oxysporum f. sp. lycopersici and root-knot nematode disease complex in tomato by use of antagonistic fungi,plant resistance and neem

Simultaneous infestation with root-knot nematodes (RKN) and Fusarium oxysporum f. sp. lycopersici (FOL) leads to formation of a disease complex that increases crop losses than effect of either RKN or FOL. In this study a management programme involving plant resistance, biological control agents, and neem was carried out to manage RKN and fusarium wilt disease complex. The biological control agents were Purpureocillium lilacinum (PL) and Trichoderma harzianum (TH) while the RKN was Meloidogyne javanica. In vitro dual culture plates were set up to test the interaction of biological control agents and FOL. Greenhouse experiments were conducted using two tomato cultivars Rambo F1 and Prostar F1. The treatments were; PL, TH, PL–TH, neem, PL neem, TH neem, and PL–TH neem. Each treatment was replicated four times and the treatments set up in a randomised complete block design in the greenhouse. Inhibition of FOL mycelial growth by TH and PL was 51.9%, and 44% respectively by the ninth day in vitro culture plates. In the cultivar, Prostar F1, the treatments PL–TH, PL, and TH in the presence or absence of neem had a FOL disease severity score significantly lower than the untreated control. Host resistance sufficed to prevent infection of Rambo F1 with FOL. The treatments PL–TH, PL and TH reduced FOL propagules and M. javanica juveniles in the roots and performed even better when combined with neem in both tomato cultivars. Therefore, a host that is resistant combined with biological control agents and organic amendments can be used in the management of RKN and FOL in tomato production.