Solution NMR structure and folding dynamics of the N terminus of a rat non-muscle alpha-tropomyosin in an engineered chimeric protein

Tropomyosin is an alpha-helical coiled-coil protein that aligns head-to-tail along the length of the actin filament and regulates its function. The solution structure of the functionally important N terminus of a short 247-residue non-muscle tropomyosin was determined in an engineered chimeric protein, GlyTM1bZip, consisting of the first 19 residues of rat short alpha-tropomyosin and the last 18 residues of the GCN4 leucine zipper. A gene encoding GlyTM1bZip was synthesized, cloned and expressed in Escherichia coli. Triple resonance NMR spectra were analyzed with the program AutoAssign to assign its backbone resonances. Multidimensional nuclear Overhauser effect spectra, X-filtered spectra and (3)J(H(N)-H(alpha)) scalar coupling were analyzed using AutoStructure. This is the first application of this new program to determine the three-dimensional structure of a symmetric homodimer and a structure not previously reported. Residues 7-35 in GlyTM1bZip form a coiled coil, but neither end is helical. Heteronuclear (15)N-(1)H nuclear Overhauser effect data showed that the non-helical N-terminal residues are flexible. The (13)C' chemical shifts of the coiled-coil backbone carbonyl groups in GlyTM1bZip showed a previously unreported periodicity, where resonances arising from residues at the coiled-coil interface in a and d positions of the heptad repeat were displaced relatively upfield and those arising from residues in c positions were displaced relatively downfield. Heteronuclear single quantum coherence spectra, collected as a function of temperature, showed that cross-peaks arising from the alpha-helical backbone and side-chains at the coiled-coil interface broadened or shifted with T(M) values approximately 20 degrees C lower than the loss of alpha-helix measured by circular dichroism, suggesting the presence of a folding intermediate. The side-chain of Ile14, a residue essential for binding interactions, exhibited multiple conformations. The conformational flexibility of the N termini of short tropomyosins may be important for their binding specificity.

Effect of interleukin (IL)-12 and IL-15 on apoptosis and proliferation of umbilical cord blood mononuclear cells

Decreased graft-versus-host disease (GVHD) in cord blood (CB) transplantation may be attributed to the immunological immaturity and susceptibility to apoptosis of CB mononuclear cells (MNCs). Cytokines like interleukin (IL)-12 and IL-15 may be used for in vivoadministration or ex vivo expansion of lymphoid cells for more rapid recovery following stem cell transplant, and for providing a graft-versus-leukemia (GVL) effect. We investigated the effects of IL-12 and IL-15, alone or in combination on apoptosis and proliferation of both CB and adult peripheral blood (APB) MNCs, with particular emphasis on CB CD4+, CD8+ and CD56+ lymphocyte subpopulations. The results of our study indicated that: (1) the combination of IL-12+IL-15 resulted in a greater degree of CB and APB apoptosis than either cytokine alone; (2) the level of both spontaneous and cytokine-induced apoptosis by IL-12 and/or IL-15 are greater in CB MNCs than in APB MNCs using TUNEL assays; (3) IL-15 is superior to IL-12 in enhancing the proliferative response in CB and APB MNCs; (4) the combination of IL-12+IL-15, but not either cytokine alone, significantly enhanced apoptosis in CD8+ and CD56+ CB subsets, but not in CD4+ CB subsets; (5) IL-12 or IL-15 alone resulted in increased proliferation in CD4+, CD8+ and CD56+ CB subsets, with IL-12+IL-15 producing the greatest increase of proliferation in all three CB subsets; and (6) IL-15 and/or IL-12 significantly upregulate Fas (CD95) expression on CB T and NK cells. These findings may have therapeutic implications when designing cytokine therapy in patients receiving CB transplant.

EXAFS study of copper in waste incineration fly ashes

Copper species such as CuCO3, Cu(OH)2, CuS and CuO were found in the bag house and EP (electrostatic precipitator) fly ashes of waste incineration processes by X-ray absorption near edge structural (XANES) spectroscopy. A small amount of Cu(I) and metallic Cu was found in the bag house fly ash. The averaged Cu-O bond distance in the fly ashes determined by EXAFS (extended X-ray absorption fine structural) was 1.96 A with coordination numbers of 2.4-3.9. However, the Cu-(O)-Cu (2nd shell) bond distance of the fly ashes in the incineration process was decreased by 0.19-0.21 A if compared to that of the CuO standard. The coordination numbers of the 2nd shell contribution to the bag house fly ash were not very significant.

Output-sliding control for a class of nonlinear systems

In this paper, a systematic output-sliding control design methodology for nonlinear multivariable systems is presented. The control law consists of a continuous nominal control and a discontinuous switching control. The former is the equivalent control for the system with all uncertainties at zero and the latter is designed for nonzero uncertainties. Simulation results indicate that the proposed switching control law drives the system state trajectories onto the chosen switching surface in finite time and the output tracking is achieved.

Robust control for a class of time varying systems via switching hypersurface design with output signals

Sliding mode control methods have been used widely since they provide robustness against parameter variations and disturbances. This paper focuses on the problem of a robust output-sliding control design for linear uncertain multi-input multi-output time-varying systems with norm-bounded uncertainty. Output signals are used for the definition of switching hypersurfaces. The formulation of a control law is emphasized. Output tracking can be achieved against a class of time varying parameter variations and external disturbances. The effectiveness of the proposed output-sliding control is confirmed by an application example.

Placing all closed loop poles of missile attitude control systems in the sliding mode via the root locus technique

This paper presents a robust control method for uncertain nonminimum phase systems with external disturbances. A systematic design algorithm is developed which links the sliding mode control and the root locus technique. Complete closed-loop pole placement is achieved in addition to the placement of the reduced order equivalent system poles. An integration function is employed in the sliding variable formulation. The output tracking error is guaranteed to vanish. The proposed method was successfully applied to control the angle of attack of a missile attitude control system.

Protein NMR spectroscopy in structural genomics

Protein NMR spectroscopy provides an important complement to X-ray crystallography for structural genomics, both for determining three-dimensional protein structures and in characterizing their biochemical and biophysical functions.

[Evaluation of two-dimensional and color Doppler ultrasonography in diagnosis of peritoneal mesothelioma]

OBJECTIVE

To evaluate diagnostic value of two-dimensional and color Doppler ultrasonography in peritoneal mesothelioma.

METHODS

Ten cases of ultrasonograms and color Doppler ultrasonographic manifestations in 3 cases of them were analysed and compared with the outcome of surgery and pathology.

RESULTS

Images of 8 cases were showed to be hypoechoic mass which some had no-echoic area; 5 to be ascites; 5 to be peritoneal thickness. With color Doppler, we saw the mass which is rich in the blood flow.

CONCLUSION

Combining clinical manifestations, ultrasonography is of benefit to initial diagnosis of peritoneal mesothelioma.

The human leukocyte antigen HLA DRB3*020/DQA1*0501 haplotype is associated with Graves' disease in African Americans

Information on genetic susceptibility to Graves' disease in African Americans is limited. We studied DRB1, DQB1, DRB3 subtypes, DQA1*0501, DQA1*0201, and CTLA-4 polymorphisms in 49 African American patients with adult onset Graves' disease and 47 racially-matched controls using PCR-based sequence-specific priming methods. There were no significant differences in DRB1 or DQB1 allelic frequencies or CTLA-4 polymorphisms between patients and controls. However, we found that the frequency of DRB3 was significantly increased in the patients (75.5% vs. 57.4%, P = 0.006, X2 = 3.52), especially for the DRB3*0202 subtype (53.1% vs. 23.4, P = 0.003, X2 = 8.91). In this one respect, the finding was in concordance with our previous observations in Caucasian patients with adult-onset Graves' disease. In addition, whereas the frequency of DQA1*0501 was increased (P = 0.018, X2 = 5.63) in our patients, the haplotype of DRB3/DQA1*0501, or DRB3*0202/DQA1*0501 was found to be more strongly associated (P = 0.008, X2 = 7.0; P = 0.0008, X2 = 11.34, respectively). These data suggest that DRB3*0202, particularly when found with DQA1*0501 in a haplotype is a susceptible gene(s) for Graves' disease in adult African Americans. Considering these data with those in Caucasian patients, our results would suggest that the primary Graves susceptible locus is likely DRB3 and not DRB1.

Minimization of cobalt nuclide emissions in supercritical water oxidation of spent resin

A rapid and complete destruction of organics in the supercritical water oxidation (SCWO) of the Co-exchanged resin was found experimentally. Due to an extremely low solubility of CoSO4 salt formed and separated effectively in the SCWO process, a minimal release of the nuclide Co would be warranted. In addition, recycling of Co nuclides is also possible by decomposition of the CoSO4 species at elevated temperatures (> 1040 K).

Fate of bromine in pyrolysis of printed circuit board wastes

Behavior of Br in pyrolysis of the printed circuit board waste with valuable copper and oil recycling has been studied in the present work. Experimentally, pyrolysis of the printed circuit board waste generated approximately 40.6% of oils, 24.9% of noncondensible gases and 34.5% of solid residues that enriched in copper (90-95%). The cuts of the oils produced from pyrolysis of the printed circuit board waste into weighted boiling fraction were primarily light naphtha and heavy gas oil. Approximately 72.3% of total Br in the printed circuit board waste were found in product gas mainly as HBr and bromobenzene. However, by extended X-ray absorption fine structural (EXAFS) spectroscopy, Cu-O and Cu-(O)-Cu species with bond distance of 1.87 and 2.95 A, respectively, were observed in the solid residues. Essentially, no Cu-Br species was found.

Robust PID tuning strategy for uncertain plants based on the Kharitonov theorem

In this paper, the Kharitonov theorem for interval plants is exploited for the purpose of synthesizing a stabilizing controller. The aim here is to develop a controller to simultaneously stabilize the four Kharitonov-defined vortex polynomials. Different from the prevailing works, the controller is designed systematically and graphically through the search of a non-conservative Kharitonov region in the controller coefficient parameter plane. The region characterizes all stabilizing PID controllers that stabilize an uncertain plant. Thus the relationship between the Kharitonov region and the stabilizing controller parameters is manifest. Extensively, to further guarantee the system with certain robust safety margins, a virtual gain phase margin tester compensator is added. Stability analysis is carried out. The control system is proved to maintain robustness at least to the pre-specified margins. The synthesized controller with coefficients selected from the obtained non-conservative Kharitonov region can stabilize the concerned uncertain plants and fulfill system specifications in terms of gain margins and phase margins.

Enhanced decomposition of NO on the alkalized PdO/Al2O3 catalyst

Experimentally, decomposition of NO on the alkalized Pd/Al2O3 catalyst is remarkably enhanced at 825-1000 K. The enhancement in N2 yield may be due to the additional basic sites on the alkalized catalyst that can trap NO molecules. However, at T > 1000 K, due to the fact that the absorbed oxygen in subsurface or bulk of Pd was involved in the formation and desorption of oxygen molecules, yield of oxygen was enhanced.

Role of exonucleolytic degradation in group I intron homing in phage T4

Homing of the phage T4 td intron is initiated by the intron-encoded endonuclease I-TevI, which cleaves the intronless allele 23 and 25 nucleotides upstream of the intron insertion site (IS). The distance between the I-TevI cleavage site (CS) and IS implicates endo- and/or exonuclease activities to resect the DNA segment between the IS and CS. Furthermore, 3' tails must presumably be generated for strand invasion by 5'-3' exonuclease activity. Three experimental approaches were used to probe for phage nucleases involved in homing: a comparative analysis of in vivo homing levels of nuclease-deficient phage, an in vitro assay of nuclease activity and specificity, and a coconversion analysis of flanking exon markers. It was thereby demonstrated that T4 RNase H, a 5'-3' exonuclease, T4 DNA exonuclease A (DexA) and the exonuclease activity of T4 DNA polymerase (43Exo), 3'-5' exonucleases, play a role in intron homing. The absence of these functions impacts not only homing efficiency but also the extent of degradation and flanking marker coconversion. These results underscore the critical importance of the 3' tail in intron homing, and they provide the first direct evidence of a role for 3' single-stranded DNA ends as intermediates in T4 recombination. Also, the involvement of RNase H, DexA, and 43Exo in homing provides a clear example of the harnessing of functions variously involved in phage nucleic acid metabolism for intron propagation.

Identification and stage-specific expression of two putative P-glycoprotein coding genes in Onchocerca volvulus

The potential for the development of ivermectin (IVM) resistance in microfilariae of Onchocerca volvulus and the existence of IVM tolerance in adult worms of this human pathogen are major concerns for the effective control of onchocerciasis. P-glycoprotein (P-gp), an ATP-binding transporter protein associated with multidrug resistance in mammals, protozoa and the nematode, Haemonchus contortus, might play important roles in the development of IVM resistance and/or in the tolerance of adult O. volvulus. In order to find the homologues of P-gp in O. volvulus, reverse transcription polymerase chain reaction (RT-PCR) has been performed in a specially synthesized cDNA pool and two full-length cDNAs have been cloned and sequenced. The first, ovpgp-1, encodes a 1278-amino-acid putative protein (OVPGP-1) with tandemly duplicated halves, each containing six putative transmembrane motifs and an ATP-binding cassette. OVPGP-1 is most similar in sequence to other eukaryotic P-gps. The second cDNA, ovplp-1, encodes a 587-amino-acid P-gp-like protein, which is only half the size of typical P-gps although it still shares high homology with them. Expression patterns of the two genes in different developmental stages have been investigated by semiquantitative RT PCR, suggesting that the expression levels of the two genes (especially ovpgp-1) may be linked with IVM sensitivity; low levels were found in IVM sensitive larval stages while high levels were found in IVM tolerant adult worms.

Overexpression of vascular endothelin-1 and endothelin-A receptors in a fructose-induced hypertensive rat model

OBJECTIVE

To examine the temporal relationship between hyperinsulinemia and hypertension in the fructose-hypertensive rat model and to study the function of endothelin-1 (ET-1) in fructose-induced hypertension.

DESIGN

Since ET-1 induces insulin resistance in conscious rats, we tested the hypothesis that both hyperinsulinemia and hypertension developed in the fructose-hypertensive rat model might be the sequelae of an elevated tissue content of ET-1 and ET(A) receptors.

MATERIALS AND METHODS

Systolic hypertension was induced within 3 weeks in male Sprague-Dawley rats fed on a fructose-rich diet. After continual monitoring of blood pressure and plasma insulin concentrations, the animals were killed at the end of experiment to determine plasma levels of ET-1, the contractile response of aortic rings to ET-1, and ET-1 and ET(A) receptor gene expressions. In a separate experiment, BQ-610 was administered to lower the effect of ET-1 in rats with fructose-induced hypertension.

RESULTS

Compared with control rats given normal chow, the fructose-fed rats developed systolic hypertension after 3 weeks of the diet (127+/-3.7 versus 110+/-5.5 mmHg, P < 0.01) and hyperinsulinemia both before (1 07.1+/-32.5 versus 48.5+/-14.3 pmol/l, P < 0.005) and after (96.6+/-63.7 versus 50.4+/-5.6 pmol/l, P< 0.05) they became hypertensive. Although plasma ET-1 levels did not differ between the rat groups, aortic ring contraction-concentration curves, indicating vessel contractility in response to ET-1, were significantly greater in these rats than in controls (F1,72 = 12.34, P< 0.00077). Messenger RNA extracted from the tail arteries and blotted with both ET-1 and ET(A) probes showed that fructose-fed rats had greater ET-1 and ET(A)-receptor gene expression than control rats. Concomitant administration of BQ-610 to rats fed on a fructose diet significantly reduced the hypertension. Conclusions These findings suggest that elevated vascular expression of ET-1 and ET(A) receptor genes may mediate the development of hypertension and hyperinsulinemia in rats fed a fructose-rich diet

Expression of pyruvate dehydrogenase isoforms during the aerobic/anaerobic transition in the development of the parasitic nematode Ascaris suum: altered stoichiometry of phosphorylation/inactivation

The pyruvate dehydrogenase complex (PDC) plays a key role in the anaerobic metabolism of the parasitic nematode Ascaris suum. Two isoforms of the alpha-subunit of pyruvate dehydrogenase (E1) have been identified: alpha I is most abundant in anaerobic adult muscle and alpha II in aerobic larvae. Both isoforms have been expressed as alpha 2 beta 2 tetramers with a muscle-specific beta-subunit, purified to apparent homogeneity, reconstituted with E1-deficient adult A. suum muscle PDC, and assayed for PDC and E1 kinase activity. Recombinant alpha II is a poor substrate for the adult E1 kinase, but its stoichiometry of phosphorylation/inactivation is similar to that reported for the human E1. Initially, inactivation parallels the incorporation of about 1 mol 32P/mol E1 and at maximal phosphorylation about 2.4 32P/mol E1 is incorporated. In contrast, recombinant alpha I (r alpha I) is phosphorylated rapidly, and substantially more phosphorylation accompanies inactivation. To examine this altered pattern of phosphorylation, the two phosphorylation sites in each E1 alpha subunit of the r alpha I (site 1 and site 2) were changed either individually or together from Ser to Ala by site-directed mutagenesis. Site 1 was phosphorylated more rapidly than site 2, but the phosphorylation of either site resulted in inactivation, and the phosphorylation of only a single E1 alpha subunit of the tetramer was necessary for inactivation. However, both E1 alpha subunits of the tetramer were phosphorylated, based on the incorporation of about 3.5 mol 32P/mol E1 at maximal phosphorylation and the altered mobility of most of the E1 alpha subunits during SDS-PAGE. These observations suggest that the regulation of both E1 isoforms is modified to maintain PDC activity during the transition to anaerobiosis.

Amelioration of insulin resistance and hypertension in a fructose-fed rat model with fish oil supplementation

In type II diabetic patients, one can detect several pathologic changes including insulin resistance and hypertension. Sprague-Dawley rats fed a fructose-rich diet (group F) exhibited these characteristic abnormalities within 2 weeks and were an excellent laboratory animal model for research on insulin action and development of hypertension. Since fish oils containing omega-3 fatty acids have a beneficial effect in preventing atherosclerotic diseases, we performed repeated experiments to test the effects of fish oil supplementation in group F rats. Compared with control rats on a normal diet (group C), group F consistently developed hypertriglyceridemia without elevated plasma free fatty acid (FFA), fasting hyperinsulinemia together with fasting hyperglycemia (insulin resistance syndrome), and systolic hypertension within 3 weeks. Insulin-stimulated glucose uptake and insulin binding of adipocytes were significantly reduced. Rats fed the same high-fructose diet but supplemented with fish oil (group O) had alleviation of all of these metabolic defects and a normalized insulin sensitivity and blood pressure. beta-Cell function as shown by plasma glucose and insulin responses to oral glucose remained intact in group F and group O. The plasma endothelin-1 (ET-1) level and ET-1 binding to adipocytes were not different among the three groups. Based on these results, we suggest that dietary high fructose induced hypertriglyceridemia and insulin resistance with normal islet function, and that the induced hypertension was not associated with plasma ET-1 abnormalities and was probably caused by other undefined pathologic changes that can be prevented by dietary omega-3 fatty acids.

Microscopic FTIR studies of lung cancer cells in pleural fluid

Structural changes associated with lung cancer and tuberculous cells in pleural fluid were studied by microscopic FTIR spectroscopy. Infrared spectra demonstrate significant spectral differences between normal, lung cancer and tuberculous cells. The ratio of the peak intensities of the 1030 and 1080 cm-1 bands (originated mainly in glycogen and phosphodiester groups of nucleic acids) differs greatly between normal and lung cancer samples. Such findings prompt the consideration that recording infrared spectra from lung cancer and tuberculous cells may be of diagnostic value. Since measurements of IR spectra of lung cancer cells in the pleural fluid can be a very rapid inexpensive process, our finding warrant exploration of this possibility in the investigation of the mechanism whereby the environmental pollution related cancers develop.

Immunohistochemical studies on protein gene product 9.5, serotonin and neuropeptides in vallate taste buds and related nerves of the guinea pig

The occurrence, distribution and innervation of guinea pig vallate papillae were investigated by means of indirect immunofluorescence and immunoperoxidase methods using antibodies against: a neuron-specific protein, protein gene product 9.5 (PGP 9.5); various neuropeptides including calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP) and galanin; a monoamine, serotonin (5-hydroxytryptamine; 5HT). Numerous PGP 9.5-immunoreactive nerve fibers were found to form plexuses in the lingual epithelium both intragemmally and extragemmally and to comprise dense bundles in the lamina propria just beneath the epithelium. Moderate numbers of PGP 9.5-immunoreactive cells were observed in the taste buds. These cells, typically spindle in shape, extended through the entire thickness of the taste bud. CGRP-immunoreactive nerve fibers were numerous in the subgemmal connective tissue and entered the epithelium to form intragemmal and extragemmal networks. A dense subgemmal SP-immunoreactive network in the vallate papilla can be linked to the presence of taste buds, even though SP-immunoreactive nerve fibers rarely occurred intragemmally. No taste cells immunoreactive for CGRP and for SP were observed. Immunoreactivity for VIP or galanin was not detected in nerve fibers and taste cells. In contrast, some taste cells and a few, fine networks of nerve fibers in the connective tissue were immunoreactive for 5HT; none of the intraepithelial fibers were 5HT-immunoreactive. We suggest that: 1) functionally, 5HT-containing cells and the CGRP-containing nerve fibers may be primarily involved in the neural transmission or its modulation of the taste sensation; and 2) VIP and galanin can be excluded from that group of substances which plays important roles in taste sensation.