Identification of interleukin-2 receptor-associated tyrosine kinase p116 as novel leukocyte-specific Janus kinase

Janus tyrosine kinase (JAK) has recently been linked to signal transduction by cytokine receptors of the hematopoietin family. We have recently described a 116-kDa tyrosine kinase (p116) present in interleukin-2 (IL-2) receptor complexes in human YT cells that showed functional characteristics of a JAK kinase. These included receptor association, rapid and transient tyrosine phosphorylation kinetics in response to ligand, and in vitro autophosphorylating tyrosine kinase activity (Kirken, R. A., Rui, H., Evans, G. A., and Farrar, W. L. (1993) J. Biol. Chem. 268, 22765-22770). Here we extend these observations by demonstrating structural homologies between IL-2-modulated p116 and prolactin-modulated JAK2 in the rat T cell line Nb2. These include similar net charge as determined by nonequilibrium pH gradient electrofocusing and related primary structure based upon phosphopeptide mapping of V8 protease-digested hyperphosphorylated proteins. This putative JAK kinase underwent marked tyrosine phosphorylation in response to IL-2, IL-4, and IL-7, lymphoid growth factors that use the common IL-2 receptor gamma-chain, but not in response to prolactin. Furthermore, polyclonal antisera to JAK1, JAK2, or tyrosine kinase 2 did not recognize either rat or human p116. However, we identified the IL-2-modulated p116 as the recently cloned novel leukocyte Janus kinase, L-JAK, using an antiserum to a peptide corresponding to the COOH terminus of human L-JAK.     

New Strategies to Overcome Present CRISPR/Cas9 Limitations in Apple and Pear: Efficient Dechimerization and Base Editing

Despite recent progress, the application of CRISPR/Cas9 in perennial plants still has many obstacles to overcome. Our previous results with CRISPR/Cas9 in apple and pear indicated the frequent production of phenotypic and genotypic chimeras, after editing of the phytoene desaturase (PDS) gene conferring albino phenotype. Therefore, our first objective was to determine if adding an adventitious regeneration step from leaves of the primary transgenic plants (T0) would allow a reduction in chimerism. Among hundreds of adventitious buds regenerated from a variegated T0 line, 89% were homogeneous albino. Furthermore, the analysis of the target zone sequences of twelve of these regenerated lines (RT0 for “regenerated T0” lines) indicated that 99% of the RT0 alleles were predicted to produce a truncated target protein and that 67% of RT0 plants had less heterogeneous editing profiles than the T0. Base editors are CRISPR/Cas9-derived new genome-editing tools that allow precise nucleotide substitutions without double-stranded breaks. Hence, our second goal was to demonstrate the feasibility of CRISPR/Cas9 base editing in apple and pear using two easily scorable genes: acetolactate synthase—ALS (conferring resistance to chlorsulfuron) and PDS. The two guide RNAs under MdU3 and MdU6 promoters were coupled into a cytidine base editor harboring a cytidine deaminase fused to a nickase Cas9. Using this vector; we induced C-to-T DNA substitutions in the target genes; leading to discrete variation in the amino-acid sequence and generating new alleles. By co-editing ALS and PDS genes; we successfully obtained chlorsulfuron resistant and albino lines in pear. Overall; our work indicates that a regeneration step can efficiently reduce the initial chimerism and could be coupled with the application of base editing to create accurate genome edits in perennial plants.     

Supporting reconfigurable security policies for mobile programs

Programming models that support code migration have gained prominence, mainly due to a widespread shift from stand-alone to distributed applications. Although appealing in terms of system design and extensibility, mobile programs are a security risk and require strong access control. Further, the mobile code environment is fluid, i.e. the programs and resources located on a host may change rapidly, necessitating an extensible security model. In this paper, we present the design and implementation of a security infrastructure. The model is built around an event/response mechanism, in which a response is executed when a security-related event occurs. We support a fine-grained, conditional access control language, and enforce policies by instrumenting the bytecode of protected classes. This method enhances efficiency and promotes separation of concerns between security policy and program specification. This infrastructure also allows security policies to change at runtime, adapting to varying system state, intrusion, and other events.     

Differential regulation of the Janus kinase-STAT pathway and biologic function of IL-13 in primary human NK and T cells: a comparative study with IL-4

We describe new methods for analyzing the apolipoproteins (apo) of the high density lipoproteins (HDL) of several species by two modes of capillary electrophoresis: size separation using a molecular sieving buffer, and capillary zone electrophoresis (CZE) using neutral coated capillaries. By either mode HDL apos were resolved within 25 min. Results for apoA-I and apoA-II mass agreed with those by electroimmunoassay; intra-assay coefficients of variation were 1.8-4.2%. The migration times of human, rat, rabbit, and bovine apoA-I during CZE were proportional to their net charge/Mr ratios. This enabled human and rabbit apoA-I to be quantified simultaneously in transgenic rabbit HDLs. CZE also resolved human apoA-I isoforms, deamidated apoA-I, and pro-apoA-I.     

Non-natural aglycones of glycopeptide antibiotics of the vancomycin group. Synthesis and antibacterial activity

A new approach for the modification of the heptapeptide core of glycopeptide antibiotics was proposed based on the replacement of amino acid residues in positions 1 and 3 in teicoplanin aglycone and in position 1 in the eremomycin aglycone. Six novel nonnatural aglycones of the vancomycin type were obtained. Compounds derived from the teicoplanin aglycone exhibited in vitro activity against Gram-positive bacteria, and two of them were also active against the vancomycin-resistant enterococci.     

N63-carboxamides of N15-alkyl and N15,N15-dialkyl derivatives of teicoplanin and deglucoteicoplanin

The synthesis and biological properties of a series of N63-carboxamides of 15-N-alkylated derivatives of teicoplanin A2 (CTA) and its aglycone (TD) are described. Among the compounds, those carrying hydrophilic groups or ionizable amino functions on the N15-alkyl chain are more soluble in water than parent N15-methylated or unmodified amides. Selected compounds were more active in vitro than CTA or TD, and a few of them were also slightly more efficacious in vivo than the parent antibiotics in streptococcal septicemia in the mouse. Their degree of activity varied with the structure and length of the N15-alkyl chains.