Inducible nuclear expression of NF-kappa B in primary B cells stimulated through the surface Ig receptor

Constitutive expression of NF-kappa B has been associated with developmental maturity in B cells on the basis of studies using continuously growing cell lines and plasmacytomas; however, little is known about the behavior of NF-kappa B in primary, mature B cells. In the present work, the regulation of NF-kappa B expression was studied by analyzing subcellular fractions of adult murine splenic B cells with the electrophoretic mobility shift assay using a kappa B-containing oligonucleotide. Although nuclear extracts from resting B cells contained kappa B-binding activity, additional kappa B-binding activity was present in cytosolic fractions in a form that became apparent after treatment with detergent. Competition analysis indicated that the DNA binding activity detected by electrophoretic gel mobility shift assay was specific for the kappa B motif, and UV photo-cross-linking showed the molecular size of kappa B-binding protein to be similar to that of the DNA binding subunit of NF-kappa B. Nuclear expression of kappa B-binding activity was markedly induced by treatment of B cells with phorbol ester or with LPS. Most notably, kappa B-binding activity was induced after surface IgR cross-linking, and the mechanism of this induction involved PKC. Further, anti-Ig-induced activity was superinduced in the presence of cycloheximide. These results indicate that nuclear NF-kappa B is rapidly induced as a result of B cell stimulation, and further suggest that NF-kappa B may play a specific role in mature B cells after ligand binding to surface Ig distinct from its postulated developmental role as a stage-specific factor involved in kappa-enhancer function.     

Seed Dormancy in Red Rice : VI. Monocarboxylic Acids: A New Class of pH-Dependent Germination Stimulants

The addition of an elicitor (glucan) to Phaseolus vulgaris cell suspension cultures increased the formation of the phytoalexin phaseollin. Intracellular pH and phosphate concentrations were studied with ³¹P nuclear magnetic resonance spectroscopy on elicitor-treated cells which were aerated during the nuclear magnetic resonance measurement. The pH of the vacuole and to a lesser extent the pH of the cytoplasm were affected at 10 minutes after elicitor addition; a decrease in pH from 5.3 to 4.8 was noted in the vacuole and from 7.46 to 7.28 in the cytoplasm. The ratio between the amount of Pi in the vacuole to that in the cytoplasm also changed within 10 minutes after elicitor addition. The signal for ATP (β-ATP) was low after elicitor addition and was high again 23 hours after elicitation. Forty-eight hours after elicitor addition, vacuolar and cytoplasmic pH had almost returned to their initial values. The rapid change in vacuolar and cytoplasmic pH may cause the change of metabolism that occurs in elicitor-treated P. vulgaris cells.     

Comparison of anti-hyperglycemic effect amongst vanadium, molybdenum and other metal maltol complexes

A wide variety of vanadium-containing complexes have been tested, both in vivo and in vitro, as possible therapeutic agents for the oral treatment of type 2 diabetes mellitus. None so far has surpassed bis(maltolato)oxovanadium(IV) (BMOV) for glucose- and lipid-lowering in an orally available formulation. Ligand choice is clearly an important factor in pharmacological efficacy of vanadium compounds as insulin enhancing agents. In this study, we kept the ligand and dose the same, varying instead the metal ion bound to the maltolato ligand in a series of binary complexes of neutral charge. A requirement for vanadyl ion as the metal ion of choice was apparent; no other metal ion tested served as a suitable substitute. Amongst [MoO(2)](2+), Co(II), Cu(II), Cr(III), and Zn(II), only [MoO(2)](2+) and Co(II) showed any hypoglycemic activity at the ED(50) dose for bis(maltolato)oxovanadium(IV), 0.6 mmolkg(-1) by oral gavage in streptozotocin (STZ)-diabetic rats within 72 h of administration of compound.     

Glucose sensors made of novel carbon nanotube-gold nanoparticle composites

Carbon nanotube and metal particle composites have been exploited to fabricate high performance electrochemical devices. However, the physical and chemical procedures to synthesize the composites are labor intensive and inefficient. Our study reveals an one-step wet chemistry method to accomplish fast and controllable production of gold nanoparticle (AuNP) and carbon naotube (CNT) composites. Such a process is sensitive to the surface charge. Especially, when functionalized with carboxyl groups, the CNTs carried negative charges and showed low level association with negatively charged AuNPs. Thermal treatment was employed to decompose the carboxyl groups and render each CNT a charge-free surface thereby achieving a high level AuNP-CNT association. The fabricated glucose sensors demonstrated dependence of their sensitivities to the amount of AuNPs on the CNTs. The enhancement of sensitivity can be attributed to an accelerated electron transfer rate from glucose oxidase Gox to the electrode. The Michaelis-Menten kinetics also indicated improved performance in the glucose sensor made of AuNP-CNTs. Therefore, our research revealed a novel approach to produce metallic nanoparticle and CNT composite for fabricating high performance electrochemical sensors.     

Acid-sensing ion channel 3 mediates peripheral anti-hyperalgesia effects of acupuncture in mice inflammatory pain

Background  

Peripheral tissue inflammation initiates hyperalgesia accompanied by tissue acidosis, nociceptor activation, and inflammation mediators. Recent studies have suggested a significantly increased expression of acid-sensing ion channel 3 (ASIC3) in both carrageenan- and complete Freund's adjuvant (CFA)-induced inflammation. This study tested the hypothesis that acupuncture is curative for mechanical hyperalgesia induced by peripheral inflammation.     

Protein structure similarity from principle component correlation analysis

Background  

Owing to rapid expansion of protein structure databases in recent years, methods of structure comparison are becoming increasingly effective and important in revealing novel information on functional properties of proteins and their roles in the grand scheme of evolutionary biology. Currently, the structural similarity between two proteins is measured by the root-mean-square-deviation (RMSD) in their best-superimposed atomic coordinates. RMSD is the golden rule of measuring structural similarity when the structures are nearly identical; it, however, fails to detect the higher order topological similarities in proteins evolved into different shapes. We propose new algorithms for extracting geometrical invariants of proteins that can be effectively used to identify homologous protein structures or topologies in order to quantify both close and remote structural similarities.     

Conditional random pattern model for copy number aberration detection

Background  

DNA copy number aberration (CNA) is very important in the pathogenesis of tumors and other diseases. For example, CNAs may result in suppression of anti-oncogenes and activation of oncogenes, which would cause certain types of cancers. High density single nucleotide polymorphism (SNP) array data is widely used for the CNA detection. However, it is nontrivial to detect the CNA automatically because the signals obtained from high density SNP arrays often have low signal-to-noise ratio (SNR), which might be caused by whole genome amplification, mixtures of normal and tumor cells, experimental noise or other technical limitations. With the reduction in SNR, many false CNA regions are often detected and the true CNA regions are missed. Thus, more sophisticated statistical models are needed to make the CNAs detection, using the low SNR signals, more robust and reliable.     

B cell antigen receptor-mediated activation of cyclin-dependent retinoblastoma protein kinases and inhibition by co-cross-linking with Fc gamma receptors.

Cross-linking the B cell Ag receptor (BCR) to surface Fc receptors for IgG (Fc gamma R) inhibits G1-to-S progression; the mechanism by which this occurs is not completely known. We investigated the regulation of three key cell cycle regulatory components by BCR-Fc gamma R co-cross-linking: G1-cyclins, cyclin-dependent kinases (Cdks), and the retinoblastoma gene product (Rb). Rb functions to suppress G1-to-S progression in mammalian cells. Rb undergoes cell-cycle-dependent phosphorylation, leading to its inactivation and thereby promoting S phase entry. We demonstrate in this paper for the first time that BCR-induced Rb phosphorylation is abrogated by co-cross-linking with Fc gamma R. The activation of Cdk4/6- and Cdk2-dependent Rb protein kinases is concomitantly blocked. Fc gamma R-mediated inhibition of Cdk2 activity results in part from an apparent failure to express Cdk2 protein. By contrast, inhibition of Cdk4/6 activities is not due to suppression of Cdk4/6 or cyclins D2/D3 expression or inhibition of Cdk-activating kinase activity. Cdk4- and Cdk6-immune complexes recovered from B cells following BCR-Fc gamma R co-cross-linking are devoid of coprecipitated D-type cyclins, indicating that inhibition of their Rb protein kinase activities is due in part to the absence of bound D-type cyclin. Thus, BCR-derived activation signals that up-regulate D-type cyclin and Cdk4/6 protein expression remain intact; however, Fc gamma R-mediated signals block cyclin D-Cdk4/6 assembly or stabilization. These results suggest that assembly or stabilization of D-type cyclin holoenzyme complexes 1) is an important step in the activation of Cdk4/6 by BCR signals, and 2) suffice in providing a mechanism to account for inhibition of BCR-stimulated Rb protein phosphorylation by Fc gamma R.