Parametric Study of CPT Resonance in Rubidium Vapor Cell for Application in Atomic Clock

The performance of Coherent Population Trapping (CPT) based atomic clocks primarily depends on the characteristics of CPT resonance. We have performed experiments to study and optimize the characteristics of CPT resonance in 87Rb atoms by measuring its contrast and full-width-at-half maximum (FWHM) as function of laser excitation and temperature of atomic vapor cells with different dimensions. A four-level atomic model is used to simulate CPT resonance characteristics along the length of atomic vapor cell. The model incorporates scaling law to understand collision dynamics in cells with different radius for a range of laser excitation intensities and the results are compared with experimental data. The quality figure, calculated from the measured values of FWHM and contrast, decreases with increase in laser intensity and improves in cells with higher dimension (radius). The optimum temperature corresponding to maximum quality figure varies with laser excitation intensity as well as cell dimension. The underlying collision dynamics and density effects that are responsible for the observed resonance characteristics are discussed

A Mycobacterium leprae Hsp65 Mutant as a Candidate for Mitigating Lupus Aggravation in Mice

Hsp60 is an abundant and highly conserved family of intracellular molecules. Increased levels of this family of proteins have been observed in the extracellular compartment in chronic inflammation. Administration of M. leprae Hsp65 [WT] in [NZBxNZW]F1 mice accelerates the Systemic Lupus Erythematosus [SLE] progression whereas the point mutated K409A Hsp65 protein delays the disease. Here, the biological effects of M. leprae Hsp65 Leader pep and K409A pep synthetic peptides, which cover residues 352–371, are presented. Peptides had immunomodulatory effects similar to that observed with their respective proteins on survival and the combined administration of K409A+Leader pep or K409A pep+WT showed that the mutant forms were able to inhibit the deleterious effect of WT on mortality, indicating the neutralizing potential of the mutant molecules in SLE progression. Molecular modeling showed that replacing Lysine by Alanine affects the electrostatic potential of the 352–371 region. The number of interactions observed for WT is much higher than for Hsp65 K409A and mouse Hsp60. The immunomodulatory effects of the point-mutated protein and peptide occurred regardless of the catalytic activity. These findings may be related to the lack of effect on survival when F1 mice were inoculated with Hsp60 or K409A pep. Our findings indicate the use of point-mutated Hsp65 molecules, such as the K409A protein and its corresponding peptide, that may minimize or delay the onset of SLE, representing a new approach to the treatment of autoimmune diseases

Cinnamomum cassia Bark in Two Herbal Formulas Increases Life Span in Caenorhabditis elegans via Insulin Signaling and Stress Response Pathways

Background: Proving the efficacy and corresponding mode of action of herbal supplements is a difficult challenge for evidence-based herbal therapy. A major hurdle is the complexity of herbal preparations, many of which combine multiple herbs, particularly when the combination is assumed to be vitally important to the effectiveness of the herbal therapy. This issue may be addressed through the use of contemporary methodology and validated animal models. Methods and Principal Findings: In this study, two commonly used traditional herbal formulas, Shi Quan Da Bu Tang (SQDB) and Huo Luo Xiao Ling Dan (HLXL) were evaluated using a survival assay and oxidative stress biomarkers in a well-established C. elegans model of aging. HLXL is an eleven herb formula modified from a top-selling traditional herbal formula for the treatment of arthritic joint pain. SQDB consists of ten herbs often used for fatigue and energy, particularly in the aged. We demonstrate here that SQDB significantly extend life span in a C. elegans model of aging. Among all individual herbs tested, two herbs Cinnamomum cassia bark (Chinese pharmaceutical name: Cinnamomi Cortex, CIN) and Panax ginseng root (Chinese pharmaceutical name: Ginseng Radix, GS) significantly extended life span in C. elegans. CIN in both SQDB and HLXL formula extended life span via modulation of multiple longevity assurance genes, including genes involved in insulin signaling and stress response pathways. All the life-span-extending herbs (SQDB, CIN and GS) also attenuated levels of H2O2 and enhanced small heat shock protein expression. Furthermore, the life spanextending herbs significantly delayed human amyloid beta (Aβ)-induced toxicity in transgenic C. elegans expressing human Aβ. Conclusion/Significance:These results validate an invertebrate model for rapid, systematic evaluation of commonly used Chinese herbal formulations and may provide insight for designing future evidence-based herbal therapy(s). Copyright: © 2010 Yu et al.published_or_final_versio

'Pergularain e I' - a plant cysteine protease with thrombin-like activity from Pergularia extensa latex

Pergularain e I, a cysteine protease with thrombin-like activity, was purified by ion exchange chromatography from the latex of Pergularia extensa. Its homogeneity was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), native PAGE and reverse-phase high-performance liquid chromatography (RP-HPLC). The molecular mass of pergularain e I by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) was found to be 23.356 kDa and the N-terminal sequence is L-P-H-D-V-E. Pergularain e I is a glycoprotein containing similar to 20% of carbohydrate. Pergularain e I constituted 6.7% of the total protein with a specific activity of 9.5 units/mg/min with a 2.11-fold increased purity. Proteolytic activity of the pergularain e I was completely inhibited by iodoacetic acid (IAA). Pergularain e I exhibited procoagulant activity with citrated plasma and fibrinogen similar to thrombin. Pergularain e I increases the absorbance of fibrinogen solution in concentration-dependant and time-dependant manner. At 10 mu g concentration, an absorbance of 0.48 was reached within 10 min of incubation time. Similar absorbance was observed when 0.2 NIH units of thrombin were used. Thrombin-like activity of pergularain e I is because of the selective hydrolysis of A alpha and B beta chains of fibrinogen and gamma-chain was observed to be insusceptible to hydrolysis. Molecular masses of the two peptide fragments released from fibrinogen due to the hydrolysis by pergularain e I at 5-min incubation time were found to be 1537.21 and 1553.29 and were in close agreement with the molecular masses of 16 amino acid sequence of fibrinopeptide A and 14 amino acid sequence of fibrinopeptide B, respectively. Prolonged fibrinogen-pergularain e I incubation releases additional peptides and their sequence comparison of molecular masses of the released peptides suggested that pergularain e I hydrolyzes specifically after arginine residues. (C) 2009 Elsevier Ltd. All rights reserved

Huo-Luo-Xiao-Ling Dan modulates antigen-directed immune response in adjuvant-induced inflammation

Ethnopharmacological relevance: HLXL is a traditional Chinese medicine that has long been used in folk medicine for the treatment of chronic inflammatory diseases. However, the precise immunological mechanisms by which HLXL mediates its anti-inflammatory activity are not fully defined. Aim of the study: To determine the effects of HLXL on antigen-specific immune parameters in adjuvant-induced inflammation model in the Lewis rat. Materials and methods: Rats were fed daily with either HLXL (2.3 g/kg) or vehicle (water) beginning 3 days before subcutaneous injection of heat-killed Mycobacterium tuberculosis H37Ra (Mtb), and then continued for another 6 days. After 9 days of Mtb injection, the draining lymph node cells were tested for T cell proliferative and cytokine responses against mycobacterial heat-shock protein 65 (Bhsp65). Moreover, sera were tested for anti-Bhsp65 antibodies and nitric oxide (NO). Results: HLXL-treated rats showed reduced T cell proliferative response to Bhsp65 compared to control rats. Furthermore, HLXL suppressed IL-17 response but enhanced IL-10 response without much effect on IFN-γ. HLXL treatment also reduced the levels of anti-Bhsp65 antibodies but not that of NO. Conclusions: HLXL feeding modulated both the cellular and the humoral immune response to Bhsp65 favoring an anti-inflammatory milieu for the suppression of adjuvant-induced inflammation. © 2009 Elsevier Ireland Ltd. All rights reserved.link_to_subscribed_fulltex

Control of autoimmune arthritis by herbal extracts and their bioactive components

Autoimmune diseases such as rheumatoid arthritis (RA) cause significant morbidity and loss of productivity. Many potent conventionally used drugs are available for these diseases, but their prolonged use is accompanied by severe adverse effects besides a high cost. Therefore, there is an unmet need for effective but less expensive medications for RA and other autoimmune diseases. Natural plant products belonging to the traditional systems of medicine, such as the traditional Chinese medicine and Indian Ayurvedic medicine, offer a vast and promising resource in this regard. However, herbal medicinal products are often poorly characterized for their composition as well as mechanisms of action. We review here the results of our systematically performed studies aimed at defining the anti-arthritic activity of three herbal extracts, namely, modified Huo-luo-xiao-ling dan (HLXL), Celastrus aculeatus Merr., and polyphenolic fraction of green tea (Camellia sinensis), as well as a purified compound Celastrol, a bioactive component of Celastrus. Specifically, we examined the effects of these herbal products on the immunological, biochemical and molecular biological effector pathways in autoimmune arthritis. We have also reviewed here related studies on these herbal products by other investigators. Taken together, we suggest further testing of these herbal products in RA patients