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  • Begum Cantu posted an update 3 weeks, 4 days ago

    Inteins are selfish genetic elements residing in open reading frames that can splice post-translationally, resulting in the ligation of an uninterrupted, functional protein. Like other inteins, the DNA polymerase B (PolB) intein of the halophilic archaeon Haloferax volcanii has an active homing endonuclease (HEN) domain, facilitating its horizontal transmission. Previous work has shown that the presence of the PolB intein exerts a significant fitness cost on the organism compared to an intein-free isogenic H. volcanii. Here, we show that mutation of a conserved residue in the HEN domain not only reduces intein homing but also slows growth. Surprisingly, although this mutation is far from the protein splicing active site, it also significantly reduces in vitro protein splicing. Moreover, two additional HEN domain mutations, which could not be introduced to H. volcanii, presumably due to lethality, also eliminate protein splicing activity in vitro. These results suggest an interplay between HEN residues and the protein splicing domain, despite an over 35 Å separation in a PolB intein homology model. The combination of in vivo and in vitro evidence strongly supports a model of codependence between the self-splicing domain and the HEN domain that has been alluded to by previous in vitro studies of protein splicing with HEN domain-containing inteins.We developed a hybrid synthetic circuit that co-opts the genetic regulation of the native bacterial quorum sensing autoinducer-2 and imposes an extra external controller for maintaining tightly controlled gene expression. ARRY382 This dual-input genetic controller was mathematically modeled and, by design, can be operated in three modes a constitutive mode that enables consistent and high levels of expression; a tightly repressed mode in which there is very little background expression; and an inducible mode in which concentrations of two signals (arabinose and autoinducer-2) determine the net amplification of the gene(s)-of-interest. We demonstrate the utility of the circuit for the controlled expression of human granulocyte macrophage colony stimulating factor in an engineered probiotic E. coli. This dual-input genetic controller is the first homologous AI-2 quorum sensing circuit that has the ability to be operated in three different modes. We believe it has the potential for wide-ranging biotechnological applications due its versatile features.Tools for live cell imaging of multiple nonrepetitive genomic loci in mammalian cells are necessary to study chromatin dynamics. Here, we report a new system based on two chromosomally integrated orthogonal irregular repeat arrays and particularly a new general strategy to construct irregular repeat arrays. Briefly, we utilized a “bridge oligonucleotide-mediated ligation” protocol to assemble 8-mer repeats de novo which were then combined into a final 96-mer repeat array using Golden Gate cloning. This strategy was used for assembling a new mutant TetO irregular repeat array, which worked orthogonally to the wild type TetO repeat. Single copy integration of the new repeat array did not cause replication deficiencies at the tagged locus. Moreover, the mutant TetO irregular repeat could also be visualized by CRISPR imaging. Our new irregular repeat assembly method demonstrates a generally applicable strategy that can be used for assembling additional orthogonal repeat arrays for imaging genomic loci and irregular repeats to visualize RNA or proteins via signal amplification.

    Concurrent chronic obstructive pulmonary disease (COPD) and metabolic syndrome (MetS) represent an important clinical phenotype with overlapping symptomology. The effect of MetS in COPD patients was assessed following treatment with nebulized glycopyrrolate (GLY; administered via eFlow® Closed System Nebulizer).

    Posthoc analyses were performed on pooled lung function, patient-reported outcome (PRO) and safety data by MetS status from patients treated with placebo, GLY 25 and 50 mcg twice daily in two 12-week studies (GOLDEN 3 and 4; N=1293). Patients with MetS were characterized as having ≥ 3 of hypertension, hyperlipidemia, diabetes, body mass index (BMI) > 30 kg/m

    risk factors. The results are presented for the Food and Drug Administration-approved GLY 25 mcg dose.

    A total of25% of patients met MetS criteria.At baseline, the MetS subgroup had higher BMIs, more ex-smokers, greater incidences of cardiovascular risk factors, and MetS-specific risk factors were 2-14 times higher than non-MetS. At 12 in COPD patients.

    To compare two different embolic materials, water-in-oil (W/O) emulsion followed by gelatin particles and microspheres in transarterial embolization (TAE), using a rat hepatocellular carcinoma model.

    Twenty rats bearing N1S1 cells were divided into the W/O emulsion group and Microsphere group. Water-in-oil emulsion was created by a glass membrane emulsification device. The tumor vascularity was measured by contrast-enhanced ultrasonography 24h before and 10min and 48h after TAE. Tumor necrosis, hepatic infarction ratio surrounding the tumor, and locations of the embolic materials 48h after TAE were assessed. The changes of serum liver enzymes were also evaluated. Statistical significance was determined by using either the Mann-Whitney U-test or Fisher’s exact test.

    The tumor vascularity 48h after TAE was significantly higher in the Microsphere group (20.1 vs. 3.76%, P = 0.016). The overflow of Lipiodol into the portal veins surrounding the tumor was seen, whereas microspheres were seen only in the artery. The percentage of necrotic area and complete response ratio in the W/O emulsion group was significantly higher (99.9 vs. 87.6%, P = 0.029 and 87.5 vs. 28.6%, P = 0.041, respectively). Serum aspartate aminotransferase and serum alanine aminotransferase levels 48h after TAE were significantly higher in the W/O emulsion group (P < 0.01).

    The embolization using W/O emulsion followed by gelatin particles showed stronger antitumor effects with the occlusion of both the tumor feeding artery and the portal vein compared with microspheres, which occluded only the arteries.

    The embolization using W/O emulsion followed by gelatin particles showed stronger antitumor effects with the occlusion of both the tumor feeding artery and the portal vein compared with microspheres, which occluded only the arteries.

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