Swertia (Gentianaceae): chemical and pharmacological aspects

A compilation of the constituents isolated from Swertia species covering the literature up to December 2003 is presented. The botanical classification and ethno-pharmacology of Swertia plants, as well as the biological activities and pharmacological applications of both distinct phytochemicals and medicinally active plant materials (formulations, extracts, etc.) are discussed in detail.     

Chiral symmetry-breaking transition in growth front of crystal phase of 1,1'-binaphthyl in its supercooled melt

Although the theory of spontaneous chiral symmetry-breaking in open systems was proposed some time ago, experimental realization of this phenomenon has not been achieved. In this article, we note that the crystal growth front of 1,1'-binaphthyl shows many of the characteristics of an open system in which chiral symmetry-breaking has occurred. We studied the temperature profiles of the crystallizing surface and obtained X-ray diffraction data of the crystals grown from the melt under controlled conditions. The data show that, under appropriate conditions, the observed bimodal probability distribution of enantiomeric excess (ee) with maxima approximately 60% is due exclusively to chiral crystals and not due to racemic crystals of 1,1'-binaphthyl that can also form at large supercooling. The mass independence of the ee shows that the growing front maintains a constant ee, which is a clear signature of open systems in steady state. Chirality 16:131-136, 2004.     

Therapeutic potential of Lactobacillus ingluviei ADK10, a newly established probiotic organism against acetaminophen induced uremic rats

In the present study, Lactobacillus ingluviei ADK10 (Acc. No. JQ395039) from intestinal origin was tested for its probiotic characteristic as well as uremia ameliorating activity on acetaminophen induced uremic rats. The results revealed that L. ingluviei ADK10 was able to tolerate pH 3.0–9.0 and 0.5% bile salt along with good hydrophobicity (67%) and adherence index with Ht-29 cell line on 258/100 cells. It was susceptible to 20 antibiotics. The organism was able to degrade food ingredients, like starch and milk proteins. The strain showed significant growth inhibition of Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Shigella dysentery, Pseudomonas aeruginosa, and Klebsiella pneumoniae (average diameter of 10 mm). The therapeutic potentiality of this probiotic bacterium was tested against acetaminophen induced uremic rats. It was found that supplementation of L. ingluviei ADK10 for 14 days with food reduced severe increase of uremic profiles, such as blood urea (85%), creatinine (68%) and uric acid (41%) in comparison to the uremic rats. Moreover, during the feeding of rats with probiotic strain at a dose of 1×10⁹ bacteria, reduction of enterobacteria in faeces was observed. Our studies indicated that L. ingluviei ADK10 could be used as a health-promoting probiotic along with antiuremic efficacy.     

Flow cytometry‐based enrichment for cell shape mutants identifies multiple genes that influence Helicobacter pylori morphology

The helical cell shape of Helicobacter pylori is highly conserved and contributes to its ability to swim through and colonize the viscous gastric mucus layer. A multi‐faceted peptidoglycan (PG) modification programme involving four recently characterized peptidases and two accessory proteins is essential for maintaining H. pylori's helicity. To expedite identification of additional shape‐determining genes, we employed flow cytometry with fluorescence‐activated cell sorting (FACS) to enrich a transposon library for bacterial cells with altered light scattering profiles that correlate with perturbed cell morphology. After a single round of sorting, 15% of our clones exhibited a stable cell shape defect, reflecting 37‐fold enrichment. Sorted clones with straight rod morphology contained insertions in known PG peptidases, as well as an insertion in csd6, which we demonstrated has ld ‐carboxypeptidase activity and cleaves monomeric tetrapeptides in the PG sacculus, yielding tripeptides. Other mutants had only slight changes in helicity due to insertions in genes encoding MviN/MurJ, a protein possibly involved in initiating PG synthesis, and the hypothetical protein HPG27_782. Our findings demonstrate FACS robustly detects perturbations of bacterial cell shape and identify additional PG peptide modifications associated with helical cell shape in H. pylori.     

Population based family history analysis of Brahmins in a small town in India for the prevalence of type-2 diabetes mellitus

OBJECTIVES:

The objective of this study is to determine the inheritance pattern of type-2 diabetes and make stratification for the general population risk.

MATERIALS AND METHODS:

A questionnaire was developed for o btaining the family history. Analysis of the data was carried out by using student and Chi-square tests and for stratification; the guidelines of Scheuner et al. were followed.

RESULTS:

The pattern of inheritance is the male sex specific (χ² =13.44). The mean age of onset of diabetes in parents was 58.61 ± 2.94 and in offspring 46.75 ± 2.54. In all 47.22 ± 11.53% families were found in high risk and 31.94 ± 10.77% in the moderate risk category. In female diabetics, the onset was in the age range of 41-60 years.

CONCLUSION:

We found a high-risk of diabetes and familial clustering in successive generations of Brahmins with prominent male sex specificity. In females onset of diabetes was coinciding with the period around menopause.     

Autoantibody depletion ameliorates disease in murine experimental autoimmune encephalomyelitis

Much data support a role for central nervous system antigen-specific antibodies in the pathogenesis of multiple sclerosis (MS). The effects of inducing a decrease in (auto)antibody levels on MS or experimental autoimmune encephalomyelitis (EAE) through specific blockade of FcRn, however, remain unexplored. We recently developed engineered antibodies that lower endogenous IgG levels by competing for binding to FcRn. These Abdegs (“antibodies that enhance IgG degradation”) can be used to directly assess the effect of decreased antibody levels in inflammatory diseases. In the current study, we show that Abdeg delivery ameliorates disease in an EAE model that is antibody dependent. Abdegs could therefore have promise as therapeutic agents for MS.     

Structural investigation of a heteroglycan isolated from the fruit bodies of an ectomycorrhizal fungus Astraeus hygrometricus

A polysaccharide fraction (AQS-II) has been isolated from the hot aqueous extract of the fruits of an ectomycorrhizal fungus Astraeus hygrometricus. It was found to contain 63% polysaccharide and 35% protein. The polysaccharide part contains glucose, galactose, and fucose in a 2:1:1 molar ratio. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, HMBC, and HSQC) the structure of the repeating unit of the polysaccharide was established as [structure: see text].     

<Emphasis Type="Italic">O</Emphasis>-acetylation of sialic acids is required for the survival of lymphoblasts in childhood acute lymphoblastic leukemia (ALL)

Exploiting the selective affinity of Achatinin-H towards 9-O-acetylneuraminic acid(α2-6)GalNAc, we have demonstrated the presence of 9-O-acetylated sialoglycoproteins (Neu5,9Ac₂-GPs) on hematopoietic cells of children suffering from acute lymphoblastic leukemia (ALL), indicative of defective sialylation associated with this disease. The carbohydrate epitope of Neu5,9Ac₂-GPs_ALL was confirmed by using several synthetic sialic acid analogues. They are functionally active signaling molecules as demonstrated by their role in mediating lymphoproliferative responses and consequential increased production of IFN-γ due to specific stimulation of Neu5,9Ac₂-GPs on PBMC_ALL with Achatinin-H. Cells devoid of 9-O-acetylations (9-O-AcSA⁻) revealed decreased nitric oxide production as compared to 9-O-AcSA⁺ cells on exposure to IFN-γ. Under this condition, a decrease in viability of 9-O-AcSA⁻ cells as compared to 9-O-AcSA⁺ cells was also observed which was reflected from increased caspase 3 activity and apoptosis suggesting the protective role of this glycotope. These Neu5,9Ac₂-GPs are also capable of inducing disease-specific anti-Neu5,9Ac₂-GPs antibodies in ALL children. Additionally, we have observed that disease-specific anti-Neu5,9Ac₂-GPs have altered glycosylation profile, and they are incapable of exerting a few Fc-glycosylation-sensitive effector functions. These observations hint toward a disbalanced homeostasis, thereby enabling the cancer cells to escape host defense. Taken together, it may be hypothesized that Neu5,9Ac₂-GPs and their antibodies play a prominent role in promoting the survival of lymphoblasts in ALL.     

CD1d favors MHC neighborhood,GM1 ganglioside proximity and low detergent sensitive membrane regions on the surface of B lymphocytes

Background

Cluster of differentiation 1 (CD1) represents a family of proteins which is involved in lipid-based antigen presentation. Primarily, antigen presenting cells, like B cells, express CD1 proteins. Here, we examined the cell-surface distribution of CD1d, a subtype of CD1 receptors, on B lymphocytes.

Methods

Fluorescence labeling methods, including fluorescence resonance energy transfer (FRET), were employed to investigate plasma membrane features of CD1d receptors.

Results

High FRET efficiency was observed between CD1d and MHC I heavy chain (MHC I-HC), β₂-microglobulin (β₂m) and MHC II proteins in the plasma membrane. In addition, overexpression of CD1d reduced the expression of MHC II and increased the expression of MHC I-HC and β₂m proteins on the cell-surface. Surprisingly, β₂m dependent CD1d isoform constituted only ~ 15% of the total membrane CD1d proteins. Treatment of B cells with methyl-β-cyclodextrin (MβCD) / simvastatin caused protein rearrangement; however, FRET demonstrated only minimal effect of these chemicals on the association between CD1d and GM₁ ganglioside on cell-surface. Likewise, a modest effect was only observed in a co-culture assay between MβCD/simvastatin treated C1R–CD1d cells and invariant natural killer T cells on measuring secreted cytokines (IFNγ and IL4). Furthermore, CD1d rich regions were highly sensitive to low concentration of Triton X-100. Physical proximity between CD1d, MHC and GM₁ molecules was also detected in the plasma membrane.

Conclusions

An intricate relationship between CD1d, MHC, and lipid species was found on the membrane of human B cells.

General significance

Organization of CD1d on the plasma membrane might be critical for its biological functions.