Toll-like receptor 9 regulates tumor necrosis factor-alpha expression by different mechanisms. Implications for osteoclastogenesis.

CpG oligodeoxynucleotides (CpG-ODNs), mimicking bacterial DNA, stimulate osteoclastogenesis via Toll-like receptor 9 (TLR9) in receptor activator of NF-kappa B ligand (RANKL)-primed osteoclast precursors. This activity is mediated via tumor necrosis factor (TNF)-alpha induction by CpG-ODN. To further reveal the role of the cytokine in TLR9-mediated osteoclastogenesis, we compared the ability of CpG-ODN to induce osteoclastogenesis in two murine strains, BALB/c and C57BL/6, expressing different TNF-alpha alleles.

TNF-alpha expression is transcriptionally regulated by RANK ligand.

Tumor necrosis factor (TNF)-alpha is known for its osteoclastogenic and resorptive activities. Induction of osteoclastogenesis by receptor activator of NF-kappaB ligand (RANKL) is accompanied by increased TNF-alpha expression. In the present study we investigated the mechanism by which RANKL induces expression of TNF-alpha in osteoclast precursors.

Synchronous cultures from the baby machine. A model for animal cells.

A baby-machine system that produces newborn Escherichia coli cells from cultures immobilised on a membrane was developed many years ago in an attempt to attain optimal synchrony with minimal disturbance of steady-state growth, and a model designed to characterise the nature and quality of the synchrony of such cells in a quantitative manner has been published. The baby machine has now been adapted for animal cells, and the present article is an attempt to modify the model to include these cells as well. The model consists of five elements, giving rise to five adjustable parameters (and a proportionality constant): a major, essentially synchronous group of cells with ages distributed normally about zero; a minor, random component from a steady-state population on the membrane that had undergone only very little age selection during the elution process; a fixed background count, to allow for the signals recorded by the electronic particle counter produced by debris and electronic noise; a time-shift, to account for differences between time of cell division and end of sample collection; and the coefficient of variation of the interdivision-time distribution, taken to be reciprocal-normal.

Bacterial shape maintenance: an evaluation of various models.

In this article, we examine a large number of combinations of growth models, with separate attention to cell volume, cylindrical surface-area, polar caps, nascent poles, onset of constriction, precision of cell division and interdivision-time dispersion, for Escherichia coli cells growing in steady state at various doubling times. Our main conclusion is striking, and quite general: exponential cylindrical surface-area growth is not possible, irrespective of the behaviour of cell volume, the polar regions, the nascent poles, or any other feature of cell growth-such cells never reach steady state. The same is true of linear cylindrical surface-area growth, regardless of when during the cell cycle the doubling in growth rate takes place.

The In Air phenomenon: temporal and spatial correlates of the handwriting process.

From 10 to 30% of elementary school-aged children have handwriting difficulties. Examination of such difficulties is important given the variety of academic, emotional, and social consequences that they can impose. One such common problem is the tendency of children to pause while writing.

Computerized temporal handwriting characteristics of proficient and non-proficient handwriters.

Objective: The purpose of this study was to use computerized temporal measures to examine and compare the writing process of proficient and non-proficient third-grade handwriters.

Method: A computerized digitizer system was used to compare the temporal handwriting measures of two groups of 8-9-year-old students. Classroom teachers used a questionnaire to identify 50 students who were non-proficient handwriters and 50 students who were proficient handwriters.

Modulation of TNF-alpha expression in bone marrow macrophages: involvement of vitamin D response element.

The calcium-regulating hormone, 1,25(OH)(2)D(3), induces tumor necrosis factor-alpha (TNF-alpha) synthesis and release from bone marrow macrophages (BMMs). To investigate the mechanism of this regulation, we have examined the effects of 1,25(OH)(2)D(3) on the cytokine message. 1,25(OH)(2)D(3) increased TNF-alpha mRNA abundance in a dose- and time-dependent manner.

CpG oligodeoxynucleotides modulate the osteoclastogenic activity of osteoblasts via Toll-like receptor 9.

Regulation of osteoclastogenesis by lipopolysaccharide (LPS) is mediated via its interactions with toll-like receptor 4 (TLR4) on both osteoclast- and osteoblast-lineage cells. We have recently demonstrated that CpG oligodeoxynucleotides (CpG ODNs), known to mimic bacterial DNA, modulate osteoclastogenesis via interactions with osteoclast precursors. In the present study we characterize the interactions of CpG ODNs with osteoblasts, in comparison with LPS.

Dual modulation of osteoclast differentiation by lipopolysaccharide.

Lipopolysaccharide (LPS) modulates bone resorption by augmentation of osteoclastogenesis. It increases in osteoblasts the production of RANKL, interleukin (IL)-1, prostaglandin E2 (PGE2), and TNF-alpha, each known to induce osteoclast activity, viability, and differentiation. We examined the role of direct interactions of LPS with osteoclast precursors in promoting their differentiation.

CpG oligonucleotides: novel regulators of osteoclast differentiation.

The macrophage capability to recognize bacterial DNA is mimicked by oligodeoxynucleotides containing unmethylated CG dinucleotides ('CpG' motifs) in specific sequence contexts (CpG ODN). CpG ODN stimulates NF-kappaB activation in murine macrophages. In light of the pivotal role played by NF-kappaB in osteoclast differentiation, we examined the ability of CpG ODN to modulate osteoclastogenesis.

Synchronous cultures from the baby machine: anatomy of a model.

The baby-machine system, which produces newborn Escherichia coli cells from cultures immobilized on a membrane, was developed many years ago in an attempt to attain optimal synchrony with minimal disturbance of steady-state growth. In the present article, we describe in some detail a model designed to analyse such cells with a view to characterizing the nature and quality of the synchrony in a quantitative manner; it can also serve to evaluate the methodology itself, its potential and its limitations. The model consists of five elements, giving rise to five adjustable parameters (and a proportionality constant): a major, essentially synchronous group of cells with ages distributed normally about zero; a minor, random component from a steady-state population on the membrane that had undergone only very little age selection during the elution process; a fixed background count, to account for the signals recorded by the electronic particle counter produced by debris and electronic noise; a time-shift, to allow for differences between collection time and sampling time; and the coefficient of variation of the interdivision-time distribution, taken to be a Pearson type III.

Two cysteine residues in the DNA-binding domain of CREB control binding to CRE and CREB-mediated gene expression.

The cAMP-responsive element-binding protein (CREB) has been implicated in the regulation of numerous physiological functions including those of several hypoxia-responding genes. All CREB transcription-regulated genes harbor the eight base-pair cAMP-responsive element (CRE) or the seven base-pair AP-1 sequence. Utilizing mutational analysis and biochemical assays, we found that reduction of two cysteine residues located in the DNA-binding basic domain of CREB, enhances the binding efficiency of CREB to DNA and regulates CRE-mediated gene expression.

Tumor necrosis factor-alpha mediates RANK ligand stimulation of osteoclast differentiation by an autocrine mechanism.

Osteoblasts or bone marrow stromal cells are required as supporting cells for the in vitro differentiation of osteoclasts from their progenitor cells. Soluble receptor activator of nuclear factor-kappaB ligand (RANKL) in the presence of macrophage colony-stimulating factor (M-CSF) is capable of replacing the supporting cells in promoting osteoclastogenesis. In the present study, using Balb/c-derived cultures, osteoclast formation in both systems-osteoblast/bone-marrow cell co-cultures and in RANKL-induced osteoclastogenesis-was inhibited by antibody to tumor necrosis factor-alpha (TNF-alpha), and was enhanced by the addition of this cytokine.

Evolution of viruses by acquisition of cellular RNA or DNA nucleotide sequences and genes: an introduction.

The origins of virus evolution may be traced to Archeabacteria since Inouye and Inouye (6) discovered a retroelement with a gene for reverse transcriptase in the bacterial genome and in the satellite, multiple copy single stranded DNA (msDNA) in the soil bacterium Myxococcus xanthus. It was possible (8) to define the evolution of retroelements in eukaryotic cells of plants, insects (gypsy retrovirus) and vertebrates. The replication of RNA viruses in eukaryotic cells allowed for the viral RNA genome to integrate a cellular ubiquitin mRNA, as reported for BVDV (24).

Protein tyrosine kinases in bacterial pathogens are associated with virulence and production of exopolysaccharide.

In eukaryotes, tyrosine protein phosphorylation has been studied extensively, while in bacteria, it is considered rare and is poorly defined. We demonstrate that Escherichia coli possesses a gene, etk, encoding an inner membrane protein that catalyses tyrosine autophosphorylation and phosphorylation of a synthetic co-polymer poly(Glu:Tyr). This protein tyrosine kinase (PTK) was termed Ep85 or Etk.