Retrocyclin, A Potent Hiv-1 Entry Inhibitor

Human immununodeficiency virus (HIV) infection is the leading cause of death due to viral infections worldwide. In the absence of an effective vaccine or consistent male condom use, there is a clear need for female-controlled preventatives such as topical vaginal microbicides. Recent attention has been focused on developing natural antimicrobial peptides, as anti-retroviral microbicides. Increasing evidence suggests that cationic antimicrobial peptides such as defensins are effective HIV-1 inhibitors. Human alpha- and beta-defensins contribute substantially to innate immune defenses against microbial and viral infections. Certain nonhuman primates also produce theta-defensins – 18 residue cyclic peptides that are potent HIV-1 entry inhibitors. Multiple human theta-defensin genes exist, but they harbor a premature termination codon that blocks translation. Consequently, the theta-defensins (retrocyclins) encoded within the human genome are not expressed as peptides. In vivo production of thetadefensins in rhesus macaques involves the post-translational ligation of two nonapeptides, each derived from a 12-residue demidefensin precursor. Neither the mechanism of this unique process nor its existence in human cells is known. To ascertain if human cells retained the ability to process demidefensins, we transfected human promyelocytic cells with plasmids containing repaired retrocyclin-like genes. The expected peptides were isolated, their sequences were verified by mass spectrometric analyses, and their anti-HIV-1 activity was confirmed in vitro. Our study reveals for the first time, to our knowledge, that human cells have the ability to make cyclic theta-defensins. Given this evidence that human cells could make theta-defensins, we attempted to restore endogenous expression of retrocyclin peptides. Since human thetadefensin genes are transcribed, we used aminoglycosides to read-through the premature termination codon found in the mRNA transcripts. This treatment induced the production of intact, bioactive retrocyclin-1 peptide by human epithelial cells and cervicovaginal tissues. The ability to reawaken retrocyclins genes from their 7 million years of slumber using aminoglycosides could provide a novel way to secure enhanced resistance to HIV-1 infection. Our studies on retrocyclin reveal that they are potential candidates to develop as topical vaginal microbicides to prevent sexual transmission of HIV-1. Mucosal surfaces of the vagina are the portals for heterosexual transmission of HIV-1 and therefore play a fundamental role in the pathogenesis of primary infection. In a search for direct biological evidence for the role of human vaginal fluid in innate host defense, we characterized the anti-HIV-1 function of cationic polypeptides within minimally manipulated vaginal fluid. In our studies, we revealed that vaginal fluid confers intrinsic anti-HIV-1 properties against both X4 and R5 strains of HIV-1, and could protect against HIV-1 infection and reduce proviral genome integration in organotypic cultures of human cervicovaginal tissue. The majority of this activity was contained in the cationic polypeptide fraction, and the depletion of cationic polypeptides using a selective cation-exchange resin ablated most of the intrinsic activity against HIV-1. By adding the cationic polypeptide fraction to depleted vaginal fluid, we were able to restore activity against HIV-1. Using a proteomic approach, we identified 18 cationic polypeptides within vaginal fluid, nearly all of which are either known antimicrobials or have other purported roles in host defense. Interestingly, physiologic concentrations of 13 of the cationic polypeptides were alone not active against HIV-1, yet in concert they partially restored the anti-HIV-1 activity of cation-depleted vaginal fluid. These results suggest that synergism between cationic polypeptides is complex and full anti-HIV-1 activity likely involves the aggregate of the cationic peptides and proteins in the acidic human vaginal fluid. Interestingly, retrocyclins retained complete anti-HIV-1 activity in the presence of human vaginal fluid. Therefore expression of retrocyclin peptides can help activate the natural defense mechanism against HIV-1. We next investigated the regulation of expression of retrocyclin (pseudo)gene. We identified a putative interferon response cluster upstream of the retrocyclin gene. The activity of this cluster was upregulated when treated with IFN-B although to a modest extent. Interestingly, the cluster also contained the binding site for an Interferon Consensus Sequence Binding Protein (ICSBP), a known repressor of the IFN inducible genes. Deletion of the ICSBP site or addition of a known inhibitor of ICSBP resulted in the increase in the activity of the cluster, indicating a role for ICSBP in the negative regulation of expression of retrocyclins. Collectively our data suggest that the expression of this ancestral gene is tightly regulated in both a positive and negative manner via the IFN response pathway

A new synthesis of 4-hydroxycoumarins

4-Hydroxynaphthocoumarin has been synthesised by the internal condensation ofO-carbethoxy-2-acetyl-1-naphthol, thus suggesting a new general method for the synthesis of 4-hydroxycoumarins. The behaviour of 4-hydroxynaphthocoumarin has been studied; its derivatives including the corresponding dicoumarin have been prepared. By the action of potassium carbonate or sodamide on the carbethoxy ester of 2-acetyl-1-naphthol, a second product was obtained, the constitution of which is under examination

Synthetical experiments in the chromone group part XXI. synthesis of gentisin, the colouring matter of gentian root

This article does not have an abstract

Genome sequencing and analysis reveals possible determinants of Staphylococcus aureus nasal carriage

<p>Abstract</p> <p>Background</p> <p>Nasal carriage of <it>Staphylococcus aureus </it>is a major risk factor in clinical and community settings due to the range of etiologies caused by the organism. We have identified unique immunological and ultrastructural properties associated with nasal carriage isolates denoting a role for bacterial factors in nasal carriage. However, despite extensive molecular level characterizations by several groups suggesting factors necessary for colonization on nasal epithelium, genetic determinants of nasal carriage are unknown. Herein, we have set a genomic foundation for unraveling the bacterial determinants of nasal carriage in <it>S. aureus.</it></p> <p>Results</p> <p>MLST analysis revealed no lineage specific differences between carrier and non-carrier strains suggesting a role for mobile genetic elements. We completely sequenced a model carrier isolate (D30) and a model non-carrier strain (930918-3) to identify differential gene content. Comparison revealed the presence of 84 genes unique to the carrier strain and strongly suggests a role for Type VII secretion systems in nasal carriage. These genes, along with a putative pathogenicity island (SaPIBov) present uniquely in the carrier strains are likely important in affecting carriage. Further, PCR-based genotyping of other clinical isolates for a specific subset of these 84 genes raise the possibility of nasal carriage being caused by multiple gene sets.</p> <p>Conclusion</p> <p>Our data suggest that carriage is likely a heterogeneic phenotypic trait and implies a role for nucleotide level polymorphism in carriage. Complete genome level analyses of multiple carriage strains of <it>S. aureus </it>will be important in clarifying molecular determinants of <it>S. aureus </it>nasal carriage.</p

Climate change : a transmedia experience

Access to thesis permanently restricted.Access to abstract permanently restricted.Thesis (M.A.)Department of Journalis

6:7-benzocoumaranone

6-7-Benzocoumaranone was first described by Ullmann who prepared it by the cyclization of 2-bromacetyl-1-naphthol and recorded the m.p. 91–2°. Fries prepared it later by the intramolecular acylation of α-naphthoxyacetyl bromide and recorded the m.p. 119°. A compound of the same m.p. prepared similarly from α-naphthoxyacetyl chloride has been considered by Inghamet al., to beperinaphthapyrone. 6∶7-Benzocoumaranone, m.p. 119°, has now been synthesised by an unambiguous route, starting from 1-hydroxy-2-naphthoic acid through the intermediate diazoketone, and it has been shown that the product obtained by Inghamet al. was 6∶7-benzocoumaranone

Cationic Polypeptides Are Required For Anti-Hiv-1 Activity Of Human Vaginal Fluid

Mucosal surfaces of the vagina are the portals for heterosexual transmission of HIV-1 and therefore play a fundamental role in the pathogenesis of primary infection. In the search for direct biological evidence for the role of human vaginal fluid in innate host defense, we characterized the anti-HIV-1 function of cationic polypeptides within minimally manipulated vaginal fluid. In the current study we revealed that vaginal fluid confers intrinsic anti-HIV-1 properties against both X4 and R5 strains of HIV-1 and could protect against HIV-1 infection and reduce proviral genome integration in organotypic cultures of human cervicovaginal tissue. The majority of this activity was contained in the cationic polypeptide fraction, and the depletion of cationic polypeptides using a selective cation exchange resin ablated most of the intrinsic activity against HIV-1. By adding the cationic polypeptide fraction to depleted vaginal fluid, we were able to restore activity against HIV-1. Using a proteomic approach, we identified 18 cationic polypeptides within vaginal fluid, nearly all of which are either known antimicrobials or have other purported roles in host defense. Interestingly, physiologic concentrations of 13 of the cationic polypeptides were not active alone against HIV-1, yet in concert they partially restored the anti-HIV-1 activity of cation-depleted vaginal fluid. These results suggest that synergism between cationic polypeptides is complex, and full anti-HIV-1 activity probably involves the aggregate of the cationic peptides and proteins in vaginal fluid. Copyright © 2005 by The American Association of Immunologists, Inc

Azoic dyes part IX. The behaviour of w-Benzoyl-2-Acetyl-l-naphthol towards diazonium salts

The utility, as azoic coupling components, of diketones prepared by the action of sodamide and similar reagents ono-benzoyloxyaryl methyl ketones has been investigated. 2-benzoylacetyl-1-naphthol gives weak dyeings when used as a “naphthol” for impregnation of cotton, and development with diazonium salts. The shades lacked fastness to soaping and light. On coupling the diketone in substance with diazonium salts, mono-and disazo dyes were obtained; the constitution of the former, which could have two possible structures, has been proved to be 4-benzeneazo-2-benzoylacetyl-1-naphthol by an unambiguous synthesis from 4-benzeneazo-2-acetyl-1-naphthol through the corresponding benzoate. The monoazo dye from 1-benzoylacetyl-2-naphthol has been prepared. 4-benzamido-2-benzoylacetyl-1-naphthol and 4-acetoacetamido-2-acetyl-1-naphthol have also been studied as “naphthols”. We are grateful to Imperial Chemical Industries (Dyestuffs Group) and to the Sir Dorab Tata Trust for the award of research fellowships to two of us. We are also thankful to Mr. T. S. Gore for carrying out the microanalyses