The regulation of protein synthesis and translation factors by CD3 and CD28 in human primary T lymphocytes

Background  

Activation of human resting T lymphocytes results in an immediate increase in protein synthesis. The increase in protein synthesis after 16–24 h has been linked to the increased protein levels of translation initiation factors. However, the regulation of protein synthesis during the early onset of T cell activation has not been studied in great detail. We studied the regulation of protein synthesis after 1 h of activation using αCD3 antibody to stimulate the T cell receptor and αCD28 antibody to provide the co-stimulus.     

Synthesis of pseudo-C-nucleosides from β-formyl-α,β-unsaturated ester bearing a β-furanosidic moiety

Abstract  

Pseudo-C-nucleosides have potential biological activity, and an efficient synthesis of new pseudo-C-nucleosides has been developed via the reaction of a β-formyl-α,β-unsaturated ester bearing a β-sugar moiety with hydrazines in neutral and acidic conditions. The preparation of the β-formyl-α,β-unsaturated ester was accomplished by oxidation of the secondary hydroxyl group of 3-O-benzyl-1,2-O-isopropylidene-α-d-glucofuranose, followed by elongation of its carbon chain with (ethoxycarbonylmethylene)triphenylphosphorane and oxidation of the hydroxymethyl group.     

Identification of α-type subunits of the Xenopus 20S proteasome and analysis of their changes during the meiotic cell cycle

Background  

The 26S proteasome is the proteolytic machinery of the ubiquitin-dependent proteolytic system responsible for most of the regulated intracellular protein degradation in eukaryotic cells. Previously, we demonstrated meiotic cell cycle dependent phosphorylation of α4 subunit of the 26S proteasome. In this study, we analyzed the changes in the spotting pattern separated by 2-D gel electrophoresis of α subunits during Xenopus oocyte maturation.     

A novel human NatA Nα-terminal acetyltransferase complex: hNaa16p-hNaa10p (hNat2-hArd1)

Background  

Protein acetylation is among the most common protein modifications. The two major types are post-translational N^ε-lysine acetylation catalyzed by KATs (Lysine acetyltransferases, previously named HATs (histone acetyltransferases) and co-translational N^α-terminal acetylation catalyzed by NATs (N-terminal acetyltransferases). The major NAT complex in yeast, NatA, is composed of the catalytic subunit Naa10p (N alpha acetyltransferase 10 protein) (Ard1p) and the auxiliary subunit Naa15p (Nat1p). The NatA complex potentially acetylates Ser-, Ala-, Thr-, Gly-, Val- and Cys- N-termini after Met-cleavage. In humans, the homologues hNaa15p (hNat1) and hNaa10p (hArd1) were demonstrated to form a stable ribosome associated NAT complex acetylating NatA type N-termini in vitro and in vivo.     

Efficient synthesis of tetrahydroquinolinones by acetic acid-mediated formal [3+3] cycloaddition

Abstract  

A simple and efficient method to synthesize a variety of tetrahydroquinolinones was successfully achieved by reacting various β-enaminones with several α,β-unsaturated aldehydes. This strategy can be viewed as a Br?nsted acid-mediated formal [3+3] cycloaddition.     

A Novel α-Glucosidase Inhibitor Protein from the Rhizomes of <Emphasis Type="Italic">Zingiber ottensii</Emphasis> Valeton

The objective of this study was to investigate a new protein with α-glucosidase inhibitory activity from the rhizomes of Zingiber ottensii. With a simple salting-out technique followed by single-step anion-exchange purification, the protein was successfully purified from the rhizomes. This protein was found to have three likely sub-unit types, 32.5, 15.2, and 13.8 kDa, as revealed by native and reducing SDS-PAGE analysis. Determination of the kinetics of the inhibition of α-glucosidase from Saccharomyces cerevisiae by standard enzymatic methods indicated the maximum percent inhibition; IC₅₀ and K _i of this protein were 77.5%, 30.15 μg/ml, and 140 μmol, while the K _m and V _max were 2.35 μmol and 0.11 mM/min, respectively. The inhibitory action was pH-independent within the pH range 2–10, but was potentially affected by buffer salts, and was relatively temperature-stable between 4–35 °C, with a maximum activity at 65 °C. The amino acid sequence of an internal fragment of this purified Z. ottensii rhizomal protein had a similarity to the sequence from the plant cysteine proteinase family. Although this α-glucosidase inhibitory protein was purified from Z. ottensii rhizomes and preliminarily characterized, further studies are needed prior to firm applications being envisaged.     

Synthesis of 6-chloroquinolines using benzyltrimethylammonium tetrachloroiodate as a selective chlorinating agent and an efficient generator of HCl

Abstract  

A simple and efficient one-pot synthesis of 6-chloroquinolines was achieved in good yields via the three-component reaction of 2-aminoaryl ketones, α-methylene carbonyl compounds, and BTMA ICl₄ in AcOH.     

( S )-(?)-α-Methylbenzylamine as chiral auxiliary in the synthesis of (+)-lortalamine

Abstract  

(+)-Lortalamine was synthesised using (S)-(−)-α-methylbenzylamine as a chiral auxiliary. The stereochemistry of an intermediate compound was established on the basis of X-ray crystallography, allowing unambiguous assignment of the absolute configuration.     

Ethylenebis(N-methylimidazolium) ditribromide (EBMIDTB): an efficient reagent for the monobromination of 1,3-diketones and β-ketoesters

Abstract  

Ethylenebis(N-methylimidazolium) ditribromide, a stable crystalline solid, is easily prepared by reaction of the corresponding dibromide salt with bromine in n-hexane. 1,3-Diketones and β-ketoesters can be brominated chemoselectively to the corresponding α-monobrominated products by using this reagent at 0–5 °C. Under the same reaction conditions, diethyl malonate, ethyl cyanoacetate, and malonitrile were monobrominated at moderate yield.     

Oxidation of steroidal diols and triols with air/NaH

Abstract  

The unusual air oxidation of steroidal triols and diols in the presence of sodium hydride in THF is described. The initial oxidation product, ketone or aldehyde, frequently undergoes further transformations in the reaction medium. The course of the reaction depends on the stereochemistry of the substrate. For example, oxidation of (20R)-20-hydroxymethyl-6β-methoxy-3α,5α-cyclopregnane-16β,17α-diol with air/NaH afforded 6β-methoxy-23,24,25,26,27-pentanor-3α,5α-cyclofurostane-16α,17α-diol in 60% yield whereas similar reaction of (20R)-20-hydroxymethyl-6β-methoxy-3α,5α-cyclopregnane-16α,17α-diol gave 6β-methoxy-D-homo-16a-oxa-3α,5α-cycloandrostan-16-one in 30% yield. The objective of this preliminary study was to select alcohols susceptible to air/NaH oxidation and to establish the effect of conditions on the course of the reaction.     

An Exopolysaccharide from Cultivated <Emphasis Type="Italic">Cordyceps sinensis</Emphasis> and its Effects on Cytokine Expressions of Immunocytes

The exopolysaccharide (EPS) is a polysaccharide from cultivated Cordyceps sinensis, which possesses immunomodulatory and antitumor effects, was purified by DEAE-32 cellulose and Sephadex G-200 gel. The preliminary characters of EPS were analyzed by IR and GC, and the molecular weight was estimated by gel filtration. The effect of EPS on proliferation ability of lymphocytes from ICR mice was assayed by MTT method. The mRNA and protein expression levels of several cytokines in spleen and thymus cells were detected by RT-PCR and ELISA. The results showed that EPS consists of mannose, glucose, and galactose in a ratio of 23:1:2.6. Its molecular weight is about 1.04 × 10⁵. EPS elevated proliferation ability of spleen lymphocytes only at 100 μg/ml after 48 h treatment. Tumor necrosis factor alpha (TNF-α), interferon-α (IFN-γ), and interleukin-2 (IL-2) mRNA levels in splenocytes and thymocytes were increased after EPS treatment for 2, 4, 8, or 20 h. EPS also significantly elevated splenic TNF-α and IFN-γ protein expressions at 100 μg/ml and increased thymic TNF-α and IFN-γ protein levels at 50 and 100 μg/ml. These data indicated that EPS may stimulate cytokine expressions of immunocytes.     

Protein kinase A type I activates a CRE-element more efficiently than protein kinase A type II regardless of C subunit isoform

Background  

Protein kinase A type I (PKAI) and PKAII are expressed in most of the eukaryotic cells examined. PKA is a major receptor for cAMP and specificity is achieved partly through tissue-dependent expression and subcellular localization of subunits with different biochemical properties. In addition posttranslational modifications help fine tune PKA activity, distribution and interaction in the cell. In spite of this the functional significance of two forms of PKA in one cell has not been fully determined. Here we have tested the ability of PKAI and PKAII formed by expression of the regulatory (R) subunits RIα or RIIα in conjunction with Cα1 or Cβ2 to activate a co-transfected luciferace reporter gene, controlled by the cyclic AMP responsive element-binding protein (CREB) in vivo.     

Nanocrystalline aluminium oxide: a mild and efficient reusable catalyst for the one-pot synthesis of poly-substituted quinolines via Friedlander hetero-annulation

Abstract  

o-Aminoaryl ketones undergo smooth condensation with α-methylene ketones in the presence of nanocrystalline aluminium oxide under mild reaction conditions to afford the corresponding poly-substituted quinolines in excellent yields. The catalyst can be recovered by simple filtration and can be recycled in subsequent reactions.     

Beta-arrestin inhibits CAMKKbeta-dependent AMPK activation downstream of protease-activated-receptor-2

Background  

Proteinase-activated-receptor-2 (PAR₂) is a seven transmembrane receptor that can activate two separate signaling arms: one through Gαq and Ca²⁺ mobilization, and a second through recruitment of β-arrestin scaffolds. In some cases downstream targets of the Gαq/Ca²⁺ signaling arm are directly inhibited by β-arrestins, while in other cases the two pathways are synergistic; thus β-arrestins act as molecular switches capable of modifying the signal generated by the receptor.     

10 α -Hydroxy- β -isomorphine, a by-product of the synthesis of 10 α -hydroxymorphine

Abstract  

A new compound was isolated from the reaction mixture after O-demethylation of 6-O-acetyl-10α-acetoxycodeine with boron tribromide. The structure of this compound, 10α-hydroxy-β-isomorphine, was elucidated by spectral data, and its spatial arrangement was deduced from an NOE experiment. Capillary zone electrophoresis was used for separation of morphine and its 10-hydroxy analogues.     

Synthesis of chiral α-ethylphenylamine salts of tartaric acid and novel application to cyanosilylation of prochiral ketones

Abstract  

Chiral α-ethylphenylamine tartaric acid salts were synthesized from α-ethylphenylamine by direct reaction with chiral tartaric acid. The crystal structure of S-(−)-α-ethylphenylamine-(2R,3R)-(−)-dihydroxybutanedioic acid was determined. The crystal is monoclinic, of space group P2_1/n , with a = 6.331(5) ?, b = 14.209(11) ?, c = 7.495(6) ?, α = 90.00o, β = 107.000(13)o, γ = 90.00o, λ = 0.7103 Ǻ, V = 644.7(9), Z = 2, D _c = 1.397 g/cm³, M _r  = 271.27 and F(000) = 288, R = 0.0477, and ωR = 0.0838 for 1388 observed reflections with I > 2σ(I). We then used the chiral α-ethylphenylamine tartaric acid salts as catalysts in the cyanosilylation of prochiral ketones, and moderate conversions were obtained.     

Embedding on alphabet overlap digraphs

Alphabet overlap digraphs can be viewed as a generalization of directed de Bruijn graphs. Given three integers α ≥ 1, k ≥ 2 and 1 ≤ i < k, the alphabet overlap digraph O(α, k ; i) is a digraph: the set of all words of length k over a certain alphabet with cardinality α is vertex set, and there is an arc from a vertex u to a vertex v if and only if the word of last k−i letters of u coincides with the word of first k−i letters of v. In this paper, we consider whether O(α, k ; i) can be embedded in O(α, k ; j) for given integers 1 ≤ i < j < k. In order to resolve this problem, we give an O(1)-time algorithm to decide whether there exists a permutation on {1, . . . ,k} from O(α, k ; i) to O(α, k ; j). If such a permutation exists, for any vertex of O(α, k ; i), we apply the permutation to change its label’s position and map it to a vertex of O(α, k ; j). Furthermore, we obtain an embedding from O(α, k ; i) to O(α, k ; j). Hence, we solve partly the problem. As a consequence, we show that every directed de Bruijn graph can be embedded in all alphabet overlap digraphs with the same parameters α and k.     

Production of Recombinant Porcine Interferon alpha Using PHB–Intein-Mediated Protein Purification Strategy

Interferons (IFNs) are involved in the pathogenesis and recovery of viral and other infectious diseases. Recombinant IFNs have been used as anti-infectious agents exhibiting a broad range of antiviral and immunomodulatory properties in both human and domestic animals. In this report, we describe a highly efficient and economical approach to purify porcine IFN alpha (PoIFNα) using polyhydroxybutyrate (PHB) as the affinity carrier and intein for self-cleaving removal of the affinity tag. Additionally, the conditions of protein expression and purification have been optimized. Our results suggested that culture medium containing 1.62% (w/v) of sodium lactate dramatically increases the accumulation of PHB binding protein in Escherichia coli cells. High yields of recombinant PoIFNα (30–35 mg/L, 97% purity by high-performance liquid chromatography) were obtained using intein-mediated self-cleaving conditions using a cleavage-inducing buffer with a pH of 6.5 at 20 °C for 24–36 h. The antiviral activity of the recovered recombinant PoIFNα was up to 1.4 × 10⁶ IU/mg of protein ascertained using recombinant human IFNα1 as a standard. This report also demonstrates that large-scale production of intein-mediated purification of highly pure and active recombinant PoIFNα is feasible for the purposes of experimental studies, veterinary clinic therapeutics, and swine infectious disease control.