Proteome analysis of chicken embryonic gonads: identification of major proteins from cultured gonadal primordial germ cells

The domestic chicken (Gallus gallus) is an important model for research in developmental biology because its embryonic development occurs in ovo. To examine the mechanism of embryonic germ cell development, we constructed proteome map of gonadal primordial germ cells (gPGCs) from chicken embryonic gonads. Embryonic gonads were collected from 500 embryos at 6 days of incubation, and the gPGCs were cultured in vitro until colony formed. After 7-10 days in culture, gPGC colonies were separated from gonadal stroma cells (GSCs). Soluble extracts of cultured gPGCs were then fractionated by two-dimensional gel electrophoresis (pH 4-7). A number of protein spots, including those that displayed significant expression levels, were then identified by use of matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry and LC-MS/MS. Of the 89 gPGC spots examined, 50 yielded mass spectra that matched avian proteins found in on-line databases. Proteome map of this type will serve as an important reference for germ cell biology and transgenic research.     

Adsorption-elution purification of chimeric <Emphasis Type="Italic">Bacillus stearothermophilus</Emphasis> leucine aminopeptidase II with raw-starch-binding activity

Summary A chimericBacillus stearothermophilus leucine aminopeptidase II (LAPsbd) has been constructed by introducing the raw-starch-binding domain of Bacillus sp. strain TS-23 α-amylase into the enzyme. LAPsbd was adsorbed onto raw starch and the adsorbed enzyme could be eluted from the adsorbent by soluble starch in 20 mM Tris–HCl buffer (pH 8.0). The adsorption of LAPsbd onto raw starch was affected by raw starch concentration, pH, and temperature, while the temperature and incubation time had no obvious effects on the elution of adsorbed enzyme. The molecular weight of purified enzyme was estimated to be 61 kDa. About 84% of LAPsbd in the cell free extract was recovered through one adsorption–elution cycle with a purification of 20-fold. The high quantity and purity of the recovered enzyme coupled with the easy performance make the adsorption–elution procedure suitable for industrial applications.     

Quantitative structure-activity relationships for the pre-steady state of Pseudomonas species lipase inhibitions by p-nirophenyl-N-substituted carbamates

The pre-steady states of Pseudomonas species lipase inhibitions by p-nitrophenyl-N-substituted carbamates (1-6) are composed of two steps: (1) formation of the non-covalent enzyme-inhibitor complex (E:I) from the inhibitor and the enzyme and (2) formation of the tetrahedral enzyme-inhibitor adduct (E-I) from the E:I complex. From a stopped-flow apparatus, the dissociation constant for the E:I complex, KS, and the rate constant for formation of the tetrahedral E-I adduct from the E:I complex, k2 are obtained from the non-linear least-squares of curve fittings of first-order rate constant (k(obs)) versus inhibition concentration ([I]) plot against k(obs)=k2+k2[I]/(KS+[I]). Values of pKS, and log k2 are linearly correlated with the sigma* values with the rho* values of -2.0 and 0.36, respectively. Therefore, the E:I complexes are more positive charges than the inhibitors due to the rho* value of -2.0. The tetrahedral E-I adducts on the other hand are more negative charges than the E:I complexes due to the rho* value of 0.36. Formation of the E:I complex from the inhibitor and the enzyme are further divided into two steps: (1) the pre-equilibrium protonation of the inhibitor and (2) formation of the E:I complex from the protonated inhibitor and the enzyme.     

Proteomic identification of the TRAF6 regulation of vacuolar ATPase for osteoclast function

Osteoclasts are cells specialized for bone resorption. For osteoclast activation, tumor necrosis factor receptor-associated factor 6 (TRAF6) plays a pivotal role. To find new molecules that bind TRAF6 and have a function in osteoclast activation, we employed a proteomic approach. TRAF6-binding proteins were purified from osteoclast cell lysates by affinity chromatography and their identity was disclosed by MS. The identified proteins included several heat shock proteins, actin and actin-binding proteins, and vacuolar ATPase (V-ATPase). V-ATPase, documented for a great increase in expression during osteoclast differentiation, is an important enzyme for osteoclast function; it transports proton to resorption lacunae for hydroxyapatite dissolution. The binding of V-ATPase with TRAF6 was confirmed both in vitro by GST pull-down assays and in osteoclasts by co-immunoprecipitation and confocal microscopy experiments. In addition, the V-ATPase activity associated with TRAF6 increased in osteoclasts stimulated with receptor activator of nuclear factor kappaB ligand (RANKL). Furthermore, a dominant-negative form of TRAF6 abrogated the RANKL stimulation of V-ATPase activity. Our study identified V-ATPase as a TRAF6-binding protein using a proteomics strategy and proved a direct link between these two important molecules for osteoclast function.     

Glutathione S-transferase pi as a target for tricyclic antidepressants in human brain

GST pi, the main glutathione S-transferase isoform present in the human brain, was isolated from various regions of the brain and the in vitro effect of tricyclic antidepressants on its activity was studied. The results indicated that amitripyline and doxepin - derivatives of dibenzcycloheptadiene, as well as imipramine and clomipramine - derivatives of dibenzazepine, inhibit the activity of GST pi from frontal and parietal cortex, hippocampus and brain stem. All these tricyclics are noncompetitive inhibitors of the enzyme with respect to reduced glutathione and noncompetitive (amitripyline, doxepin) or uncompetitive (imipramine, clomipramine) with respect to the electrophilic substrate. Their inhibitory effect is reversible and it depends on the chemical structure of the tricyclic antidepressants rather than on the brain localization of the enzyme. We conclude that the interaction between GST pi and the drugs may reduce their availability in the brain and thus affect their therapeutic activity. On the other hand, tricyclic antidepressants may decrease the efficiency of the enzymatic barrier formed by GST and increase the exposure of brain to toxic electrophiles. Reactive electrophiles not inactivated by GST may contribute in adverse effects caused by these drugs.     

Suberoylanilide hydroxamic acid (SAHA) at subtoxic concentrations increases the adhesivity of human leukemic cells to fibronectin

Suberoylanilide hydroxamic acid (SAHA) is an inhibitor of histone deacetylases (HDACs) which is being introduced into clinic for the treatment of hematological diseases. We studied the effect of this compound on six human hematopoietic cell lines (JURL‐MK1, K562, CML‐T1, Karpas‐299, HL‐60, and ML‐2) as well as on normal human lymphocytes and on leukemic primary cells. SAHA induced dose‐dependent and cell type‐dependent cell death which displayed apoptotic features (caspase‐3 activation and apoptotic DNA fragmentation) in most cell types including the normal lymphocytes. At subtoxic concentrations (0.5–1 µM), SAHA increased the cell adhesivity to fibronectin (FN) in all leukemia/lymphoma‐derived cell lines but not in normal lymphocytes. This increase was accompanied by an enhanced expression of integrin β1 and paxillin, an essential constituent of focal adhesion complexes, both at the protein and mRNA level. On the other hand, the inhibition of ROCK protein, an important regulator of cytoskeleton structure, had no consistent effect on SAHA‐induced increase in the cell adhesivity. The promotion of cell adhesivity to FN seems to be specific for SAHA as we observed no such effects with other HDAC inhibitors (trichostatin A and sodium butyrate). J. Cell. Biochem. 109: 184–195, 2010. © 2009 Wiley‐Liss, Inc.     

A special case of thyroid associated ophthalmopathy in the course of Graves-Basedow disease

INTRODUCTION: The exact pathogenesis of Graves' ophthalmopathy and the possibility of causal treatment of this disease still remain unclear. Currently no standard treatment guidelines have been accepted. While treatment procedures have been established in specialized centres, management of complicated and long-lasting cases is always individual. We present an unusual case of Graves' ophthalmopathy accompanied by other autoimmune diseases. CASE REPORT: Our patient, MB, female, born in 1961, was diagnosed with Graves' disease 13 years ago. Recurrent hyperthyroidism and large goitre qualified her for strumectomy (performed twice) and long-term antithyroid treatment. Four years after her initial diagnosis, relapsing severe (ophthalmopathy index: 9 points, CAS: 7 points) occurred which persisted despite continuous administration of glucocorticoids. Due to imminent blindness, orbital decompression had to be performed, three times since. Concurrent autoimmune diseases: ulcerative colitis and seronegative rheumatoid arthritis were also stated. Two years ago, due to loss of vision acuity, rapid progression of exophthalmos and recurrence of hyperthyroidism, immunosuppressive treatment with azathioprine was undertaken over a period of 12 months. The present condition of the patient is satisfactory. CONCLUSION: Judging from the discussed course of treatment, in rare and difficult cases of proliferative ophthalmopathy, early immunosuppressive treatment other than glucocorticoids, should be considered.     

Biomechanical comparison between fusion of two vertebrae and implantation of an artificial intervertebral disc

Surgical treatments for lower back pain can be distributed into two main groups: fusion (arthrodesis) and disc replacement (arthroplasty). The objective of this study was to compare, under severe loading conditions, the biomechanics of the lumbar spine treated either by fusion or total disc replacement (TDR). A three-dimensional model of a two-level ligamentous lumbar segment was created and simulated through static analyses with the finite-element method (FEM) software ABAQUS. The model was validated by comparing mobility, pressure on the facets, force in the ligaments, maximum stresses, disc bulge, and endplate deflection with measured data given in the literature. The FEM analysis predicted that the mobility of the model after arthrodesis on the upper level was reduced in all rotational degrees of freedom by an average of approximately 44%, relative to healthy normal discs. Conversely, the mobility of the model after TDR on the upper level was increased in all rotational degrees of freedom by an average of approximately 52%. The level implanted with the artificial disc showed excessive ligament tensions (greater than 500 N), high facet pressures (greater than 3 MPa), and a high risk of instability. The mobility and the stresses in the level adjacent to the arthroplasty were also increased. In conclusion, the model for an implanted movable artificial disc illustrated complications common to spinal arthroplasty and showed greater risk of instability and further degeneration than predicted for the fused model. This modeling technique provides an accurate means for assessing potential biomechanical risks and can be used to improve the design of future artificial intervertebral discs.     

Determination of glucose metabolites in stored erythrocytes and in erythrocytes from patients with thalassemia by analytical isotachophoresis

Glycolysis is for some cells, such as erythrocytes, neutrophil granulocytes and many cancer cells, the only or most important source of energy (ATP) production. Based on previous studies we developed an isotachophoretic (ITP) method which allows, in principle, the simultaneous determination of all metabolites of glycolysis. Since glucose metabolites are small anions, mobility of some of them may overlap in isotachophoresis and, therefore, partial mixed zones are generated. By variation of the leading/terminating system, however, it is possible to separate the compounds of interest. In this communication, we describe a method for analysis of glucose metabolites in erythrocytes from healthy donors during storage in blood bags, and from patients with thalassemia, with special respect to intracellular 2,3 bisphosphoglycerate, lactate and ATP/ADP. The well known characteristic changes of glycolysis in erythrocytes during blood storage and in erythrocytes from thalassemia patients, which are often analysed by separate enzymatic assays, could be confirmed with this isotachophoretic procedure. The method is currently adapted for analysis of glycolysis in neutrophil granulocytes and cancer cells which requires some modifications of sample preparation and performance of the isotachophoretic analysis.