Synthesis and Broad-Spectrum Antiviral Activity in Mice of Certain Alkyl,Alkenyl and Ribofuranosyl Derivatives of 7-Deazaguanine

Abstract

A series of alkyl, alkenyl and β-D-ribofuranosyl derivatives of 7-deazaguanine were synthesized and their ability to inhibit certain RNA virus infections was assessed in mice. 8-Chloro-7-deazaguanosine (6) protected the majority of mice infected intraperitoneally (i.p.) with benzi, encephalomyocarditis, San Angelo, or Semliki Forest virus at doses as low as 50 mg/kg/day. It was also orally active.     

Synthesis and Biophysical Studies of Modified Oligonucleotides Containing Acyclic Amino Alcohol Nucleoside Analogs

Abstract

Novel serine derivative of thymine was prepared and incorporated into oligonucleotides. These modified oligonucleotides were studied for their binding affinity with complementary DNA/RNA.     

A Transgenic Tri-Modality Reporter Mouse

Transgenic mouse with a stably integrated reporter gene(s) can be a valuable resource for obtaining uniformly labeled stem cells, tissues, and organs for various applications. We have generated a transgenic mouse model that ubiquitously expresses a tri-fusion reporter gene (fluc2-tdTomato-ttk) driven by a constitutive chicken β-actin promoter. This “Tri-Modality Reporter Mouse” system allows one to isolate most cells from this donor mouse and image them for bioluminescent (fluc2), fluorescent (tdTomato), and positron emission tomography (PET) (ttk) modalities. Transgenic colonies with different levels of tri-fusion reporter gene expression showed a linear correlation between all three-reporter proteins (R²=0.89 for TdTomato vs Fluc, R²=0.94 for Fluc vs TTK, R²=0.89 for TdTomato vs TTK) in vitro from tissue lysates and in vivo by optical and PET imaging. Mesenchymal stem cells (MSCs) isolated from this transgenics showed high level of reporter gene expression, which linearly correlated with the cell numbers (R²=0.99 for bioluminescence imaging (BLI)). Both BLI (R²=0.93) and micro-PET (R²=0.94) imaging of the subcutaneous implants of Tri-Modality Reporter Mouse derived MSCs in nude mice showed linear correlation with the cell numbers and across different imaging modalities (R²=0.97). Serial imaging of MSCs transplanted to mice with acute myocardial infarction (MI) by intramyocardial injection exhibited significantly higher signals in MI heart at days 2, 3, 4, and 7 (p<0.01). MSCs transplanted to the ischemic hindlimb of nude mice showed significantly higher BLI and PET signals in the first 2 weeks that dropped by 4^th week due to poor cell survival. However, laser Doppler perfusion imaging revealed that blood circulation in the ischemic limb was significantly improved in the MSCs transplantation group compared with the control group. In summary, this mouse can be used as a source of donor cells and organs in various research areas such as stem cell research, tissue engineering research, and organ transplantation.     

Non contiguous-finished genome sequence and description of Dielma fastidiosa gen. nov., sp. nov., a new member of the Family Erysipelotrichaceae

Dielma fastidiosa strain JC13^T gen. nov., sp. nov. is the type strain of D. fastidiosa gen. nov., sp. nov., the type species of a new genus within the family Erysipelotrichaceae. This strain, whose draft genome is described here, was isolated from the fecal flora of a healthy 16-year-old male Senegalese volunteer. D. fastidiosa is a Gram-negative anaerobic rod. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,574,031 bp long genome comprises a 3,556,241-bp chromosome and a 17,790-bp plasmid. The chromosome contains 3,441 protein-coding and 50 RNA genes, including 3 rRNA genes, whereas the plasmid contains 17 protein-coding genes.     

Non contiguous-finished genome sequence and description of Alistipes obesi sp. nov

Alistipes obesi sp. nov. strain ph8^T is the type strain of A. obesi, a new species within the genus Alistipes. This strain, whose genome is described here, was isolated from the fecal flora of a 26-year-old woman suffering from morbid obesity. A. obesi is an obligately anaerobic rod. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,162,233 bp long genome (1 chromosome but no plasmid) contains 2,623 protein-coding and 49 RNA genes, including three rRNA genes.     

Deferasirox and Vitamin D Improves Overall Survival in Elderly Patients with Acute Myeloid Leukemia after Demethylating Agents Failure

The prognosis of acute myeloid leukemia (AML) in elderly (≥65 years) patients is poor and treatment remains non-consensual especially for those who are not eligible for intensive therapies. Our group has shown that in vitro the iron chelator deferasirox (DFX) synergizes with vitamin D (VD) to promote monocyte differentiation in primary AML cells. Herein, we present results from a retrospective case-control study in which the association of DFX (1–2 g/d) and 25-hydroxycholecalciferol (100,000 IU/week) (DFX/VD) was proposed to patients following demethylating agents failure. Median survival of patients treated with DFX/VD combination (n = 17) was significantly increased in comparison with matched patients receiving best supportive care (BSC) alone (n = 13) (10.4 versus 4 months respectively). In addition, the only factor associated to an increased overall survival in DFX/VD-treated patients was serum VD levels. We conclude that DFX/VD treatment correlated with increased overall survival of AML patients in this retrospective cohort of elderly patients.     

Associative learning in biochemical networks

It has been recently suggested that there are likely generic features characterizing the emergence of systems constructed from the self-organization of self-replicating agents acting under one or more selection pressures. Therefore, structures and behaviors at one length scale may be used to infer analogous structures and behaviors at other length scales. Motivated by this suggestion, we seek to characterize various "animate" behaviors in biochemical networks, and the influence that these behaviors have on genomic evolution. Specifically, in this paper, we develop a simple, chemostat-based model illustrating how a process analogous to associative learning can occur in a biochemical network. Associative learning is a form of learning whereby a system "learns" to associate two stimuli with one another. Associative learning, also known as conditioning, is believed to be a powerful learning process at work in the brain (associative learning is essentially "learning by analogy"). In our model, two types of replicating molecules, denoted as A and B, are present in some initial concentration in the chemostat. Molecules A and B are stimulated to replicate by some growth factors, denoted as G(A) and G(B), respectively. It is also assumed that A and B can covalently link, and that the conjugated molecule can be stimulated by either the G(A) or G(B) growth factors (and can be degraded). We show that, if the chemostat is stimulated by both growth factors for a certain time, followed by a time gap during which the chemostat is not stimulated at all, and if the chemostat is then stimulated again by only one of the growth factors, then there will be a transient increase in the number of molecules activated by the other growth factor. Therefore, the chemostat bears the imprint of earlier, simultaneous stimulation with both growth factors, which is indicative of associative learning. It is interesting to note that the dynamics of our model is consistent with certain aspects of Pavlov's original series of conditioning experiments in dogs. We discuss how associative learning can potentially be performed in vitro within RNA, DNA, or peptide networks. We also describe how such a mechanism could be involved in genomic evolution, and suggest relevant bioinformatics studies that could potentially resolve these issues.     

Frequency and phenotype of JC virus-specific CD8+ T lymphocytes in the peripheral blood of patients with progressive multifocal leukoencephalopathy

JC virus (JCV)-specific CD8+ cytotoxic T lymphocytes (CTL) are associated with a favorable outcome in patients with progressive multifocal leukoencephalopathy (PML) and cross-recognize the polyomavirus BK virus (BKV). We sought to determine the frequency and phenotype in fresh blood of CD8+ T cells specific for two A*0201-restricted JCV epitopes, VP1(p36) and VP1(p100), and assess their impact on JC and BK viremia and viruria in 15 healthy subjects, eight human immunodeficiency virus-positive (HIV+) individuals, and nine HIV+ patients with PML (HIV+ PML patients) classified as survivors. After magnetic pre-enrichment of CD8+ T cells, epitope-specific cells ranged from 0.001% to 0.022% [corrected] by tetramer staining, with no significant difference among the three study groups. By use of seven-color flow cytometry, there was no predominant differentiation phenotype subset among JCV-specific CD8+ T cells in healthy individuals, HIV+ subjects, or HIV+ PML patients. However, in one HIV+ PML patient studied in the acute phase, there was a majority of activated effector memory cells. BKV DNA was undetectable in all blood samples by quantitative PCR, while a low JC viral load was found in the blood of only one HIV+ and two HIV+ PML patients. JCV and BKV DNA were detected in 33.3% and 13.3% of all urine samples, respectively, independent of the presence of JCV-specific CTL. The detection of JCV DNA in the urine was associated with the presence of a JCV VP1(p100) CTL response. Immunotherapies aiming at increasing the cellular immune response against JCV may be valuable in the treatment of HIV+ individuals with PML.     

Cobalt complexes of terpyridine ligand: crystal structure and photocleavage of DNA

Two new cobalt complexes, [Co(pytpy)(2)](ClO(4))(2), 1, and [Co(pytpy)(2)](ClO(4))(3), 2 where pytpy=pyridine terpyridine, have been synthesized and characterized. Single-crystal X-ray structure of both the complexes has been resolved. The structure shows the complexes to be a monomeric cobalt(II) and cobalt(III) species with two pytpy ligands coordinated to the metal ion to give a six coordinate complex. Both cobalt(II) and cobalt(III) complexes crystallize in meridional configuration. The interaction of these complexes with calf thymus DNA has been explored by using absorption, emission spectral, electrochemical studies and viscosity measurements. From the experimental results the DNA binding constants of 1 and 2 are found to be (1.97+/-0.15)x10(4)M(-1) and (2.7+/-0.20)x10(4)M(-1) respectively. The ratio of DNA binding constants of 1 and 2 have been estimated to be 0.82 from electrochemical studies, which is in close agreement with the value of 0.73 obtained from spectral studies. The observed changes in viscosity of DNA in the presence of increasing amount of complexes 1 and 2 suggest intercalating binding of these complexes to DNA. Results of DNA cleaving experiments reveal that complex 2 efficiently cleaves DNA under photolytic conditions while complex 1 does not cleave DNA under similar conditions.