Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chemokine receptor CXCR4 is a primary coreceptor for the HIV-1 virus. The predicted molecular weight (MW) of glycosylated CXCR4 is 45-47 kDa. However, immunoblots of whole cell lysates from human lymphocytes, monocytes, macrophages, and the Jurkat T-lymphocyte line revealed multiple MW isoforms of CXCR4. Three of the bands could be precipitated by anti-CXCR4 monoclonal antibodies (101 and 47 kDa) or coprecipitated with CD4 (62 kDa). Expression of these isoforms was enhanced by infection with a recombinant vaccinia virus encoding CXCR4. In immunoblots of two-dimensional gels, antiubiquitin antibodies reacted with the 62-kDa CXCR4 species from monocytes subsequent to coprecipitation with anti-CD4 antibodies. Culturing of monocytes and lymphocytes with lactacystin enhanced the amount of the 101-kDa CXCR4 isoform in immunoblots by three- to sevenfold. In lymphocytes, lactacystin also increased cell-surface expression of CXCR4, which correlated with enhanced fusion with HIV-1 envelope-expressing cells. Similar increases in the intensity of the 101-kDa isoform were seen after treatment with the lysosomal inhibitors monensin and ammonium chloride. Antiubiquitin antibodies reacted with multiple proteins above 62 kDa, which were precipitated with anti-CXCR4 antibodies. Our data indicate that ubiquitination may contribute to CXCR4 heterogeneity and suggest roles for proteasomes and lysosomes in the constitutive turnover of CXCR4 in primary human cells.
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PMID:CXCR4 heterogeneity in primary cells: possible role of ubiquitination. 1248 3

A protein with an N-terminal sequence showing a much lesser extent of homology than French bean and kiwi fruit thaumatin-like proteins (TLPs) to other TLPs, and possessing a molecular mass of 30 kDa which is considerably higher than those of previously reported TLPs, has been purified from the seeds of the chestnut Castanopsis chinensis Hance. The protein was unadsorbed on DEAE-cellulose in 10 mM Tris-HCl buffer (pH 7.3), and adsorbed on Affi-gel blue gel in the same buffer, on CM-cellulose in 10 mM ammonium acetate buffer (pH 4.5), and on Mono S in 20 mM ammonium acetate buffer (pH 5.5). A highly purified protein preparation was obtained after fractionation on the first three chromatographic media. Castanopsis TLP appeared as a single band (30 kDa) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and as a single peak (30 kDa) in gel filtration on Superdex 75 by fast protein liquid chromatography. The TLP exerted antifungal activity against Botrytis cinerea, Fusarium oxysporum, Mycosphaerella arachidicola, and Physalospora piricola, with an IC(50) of 0.5 microM against F. oxysporum. Castanopsis TLP was more potent than French bean and kiwi fruit TLPs in its antifungal activity toward F. oxysporum and M. arachidicola. The antifungal activity of Castanopsis TLP remained essentially unaltered after incubation at 40 degrees C for 10 min, was reduced after incubation at 60 degrees C, and disappeared after treatment at 80 degrees C. The antifungal activity underwent a decline after treatment with trypsin (enzyme:substrate ratio 1:100) at 37 degrees C for 1h but some activity remained. Castanopsis TLP exhibited a much more potent inhibitory activity on HIV-1 reverse transcriptase (IC(50) = 1.6 microM) than kiwi fruit TLP (IC(50) > or = 27 microM). Castanopsis TLP was obtained with a yield of 20 mg from 1 kg chestnut seeds.
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PMID:Isolation of a large thaumatin-like antifungal protein from seeds of the Kweilin chestnut Castanopsis chinensis. 1256 69

Recombinant proteins are often purified from microbial lysates containing high concentrations of nucleic acids. Pre-purification steps such as nuclease addition or precipitation with polyethyleneimine or ammonium sulfate are normally required to reduce viscosity and to eliminate competing polyanions before anion exchange chromatography. We report that small polycationic compaction agents such as spermine selectively precipitate nucleic acids during or after Escherichia coli lysis, allowing DNA and RNA to be pelleted with the insoluble cell debris. Analysis by spectrophotometry and protein assay confirmed a significant reduction in the concentration of nucleic acids present, with preservation of protein. Lysate viscosity is greatly reduced, facilitating subsequent processing. We have used 5mM spermine to remove nucleic acids from E. coli lysate in the purification of a hexahistidine-tagged HIV reverse transcriptase.
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PMID:Compaction agent clarification of microbial lysates. 1269 84

The formation of noncovalent complexes between the HIV-1 nucleocapsid protein p7 (NC) and RNA hairpins SL2-SL4 of the Psi-recognition element was investigated by direct infusion electrospray ionization-Fourier transform mass spectrometry (ESI-FTMS). The high resolution afforded by this method provided the unambiguous characterization of the stoichiometry and composition of complexes formed by multiple equilibria in solution. For each hairpin, the formation of a 1:1 complex was found to be the primary binding mode in solutions of intermediate salt content (150 mM ammonium acetate). Binding of multiple units of NC was observed with lower affinity and a maximum stoichiometry matching the limit calculated from the number of nucleotides in the construct and the size of the footprint of NC onto single-stranded nucleic acids, thus implying the defolding of the hairpin three-dimensional (3D) structure. Dissociation constants of 62 +/- 22 nM, 178 +/- 64 nM, and 1.3 +/- 0.5 microM were determined for SL2, SL3-2, and SL4, respectively, which are similar to values obtained by spectroscopic and calorimetric methods with the additional confidence offered by a direct, rather than inferred, knowledge of the binding stoichiometry. Competitive binding experiments carried out in solutions of intermediate ionic strength, which has the effect of weakening the electrostatic interactions in solution, provided a direct way of evaluating the stabilizing contributions of H-bonding and hydrophobic interactions that are more sensitive to the sequence and structural context of the different hairpins. The relative scale of binding affinity obtained in this environment reflects the combination of contributions provided by the different structures of both the tetraloop and the double-stranded stem. The importance of the stem 3D structure in modulating the binding activity was tested by a competitive binding experiment that included the SL3-2 RNA construct, a DNA analogue of SL3 (SL3(DNA)), and a DNA analogue in which all four loop bases were replaced with abasic nucleotides (SL3(abasic)). NC was found to bind the A-type double-stranded stem of SL3-2 RNA at least 30 times more tightly than the B-type helical structure of SL3(DNA). Eliminating the stabilization provided by the interactions with the tetraloop bases made the binding of SL3(abasic) approximately 50 times weaker than that of SL3(DNA).
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PMID:Direct mass spectrometric determination of the stoichiometry and binding affinity of the complexes between nucleocapsid protein and RNA stem-loop hairpins of the HIV-1 Psi-recognition element. 1296 98

Investigation into the mechanism of action of vaccine adjuvants provides opportunities to define basic immune principles underlying the induction of strong immune responses and insights useful for the rational development of subunit vaccines. A novel HIV vaccine composed of plasmid DNA-encoding p55 gag formulated with poly-lactide-co-glycolide microparticles (PLG) and cetyl trimethyl ammonium bromide (CTAB) elicits both serum antibody titers and cytotoxic lymphocyte activity in mice at doses two orders of magnitude lower than those required for comparable response to plasmid DNA in saline. Using this model, we demonstrated the increase in potency requires the DNA to be complexed to the PLG-CTAB microparticles. Furthermore, the PLG-CTAB-DNA formulation increased the persistence of DNA at the injection site, recruited mononuclear phagocytes to the site of injection, and activated a population of antigen presenting cells. Intramuscular immunization with the PLG-CTAB-DNA complex induced antigen expression at both the injection site and the draining lymph node. These findings demonstrate that the PLG-CTAB-DNA formulation exhibits multiple mechanisms of immunopotentiation.
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PMID:Mechanisms of increased immunogenicity for DNA-based vaccines adsorbed onto cationic microparticles. 1464

Prostratin, a non-tumour promoting phorbol ester, exhibit a potent anti-HIV activity against human immunodeficiency virus type 1 (HIV-1). However, the antiviral mechanism of prostratin is not well defined. In the present study, we report that prostratin exhibits potent antiviral activity against different strains of HIV-1 (subtypes B and D), a clinical HIV isolate (L1), HIV-2 (ROD and EHO) and SIV (MAC251) with EC50-values ranging from 0.02-0.09 microg/ml. Prostratin was equally active against HIV strains resistant to the polyanionic binding inhibitor dextran sulphate, the fusion inhibitor T-20 (enfuvirtide), nucleoside reverse transcriptase inhibitors (NRTIs) or protease inhibitors (PIs). In contrast, prostratin lost 4.4- and 6.8-fold of its effect against the HIV strains resistant to AMD3100 and the quaternary ammonium salt QAS10+, respectively. As shown by time-of-addition experiments, prostratin needs to be present at the time of viral adsorption to exert its antiviral activity. We selected an HIV strain (NL4.3/PROS) resistant to prostratin in MT-4 cells. The sensitivity of NL4.3/PROS towards prostratin, dextran sulphate and QAS10+ was reduced by 3.2, 4.1 and >50-fold, respectively. However, NL4.3/ PROS was still sensitive to AMD3100, T-20, NRTIs (zidovudine and nevirapine) and a PI (ritonavir). Recombination of the gp160-gene of the NL4.3/PROS strain in a NL4.3 wild-type molecular clone fully rescued its phenotypic resistance. DNA sequencing of the NL4.3/PROS strain revealed mutations throughout the gp120 gene previously associated with resistance towards other HIV entry inhibitors. We concluded that prostratin inhibits the entry step of the replication cycle of HIV by interacting with a cellular target necessary for viral entry.
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PMID:Potent and selective inhibition of HIV and SIV by prostratin interacting with viral entry. 1496 38

Subtraction hybridization was earlier used to obtain cDNA clones corresponding to human genes upregulated in HIV-associated centroblast lymphoma (CL) as compared with HIV-associated immunoblast lymphoma (IL). With inverse subtraction hybridization, clones were isolated that correspond to genes upregulated in IL compared with CL. In addition to cDNAs characterized earlier, the resulting clones contained several (seven CL-specific and three IL-specific) sequences with unknown functions. To identify the lymphoma-specific genes that are overexpressed in early carcinogenesis, Northern blotting was used to assess the level of gene transcription in two human fibroblast lines and in their derivatives immortalized with either a temperature-sensitive mutant of SV-40 or with pSV3neo carrying the SV-40 A gene, considering the latter as a model of early cell malignant transformation. Increased expression in at least one immortalized line compared with normal fibroblasts was observed for set, a-myb, ND1, ND2, ND4 (NADH dehydrogenase subunits 1, 2, and 4), COX2, COX3 (cytochrome-c-oxidase subunits 2 and 3), KIAA0129, and the gene corresponding to cDNA hss2-1-7-10. High expression of these genes was assumed to be associated not only with lymphomogenesis, but also with early transformation (immortalization) of other, nonlymphoid cells. Expression of the calpain gene and the gene corresponding to cDNA hss2-2-9-5 proved to be lower in immortalized than in normal fibroblasts. This was considered indicative of an alternative mechanism of fibroblast transformation or of different processes regulating the expression of these genes in early and late carcinogenesis.
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PMID:[Analysis of expression of a series of lymphoma-specific genes in human fibroblasts immortalized by SV40 virus]. 1512 32

A 53-year-old, male patient presented with pain in the middle area of the back of his left foot. The painful area was associated with a reddish dome-shaped swelling of 24 by 18 mm which had ulcerated in the center part. Histopathologically, the cutaneous lesion consisted of an ulcer surrounded by abscess and granuloma and numerous acid-fast organisms were observed. Subsequently, the area just below the left inguinal area developed redness and swelling approaching the size of a quail egg. The patient responded favorably with rifampicin, levofloxacin, and minocycline therapy. The patient was immunodeficient, but negative for HIV-1 and HIV-2 antibodies and the etiology of his immunodeficient state is unclear. Skin tissues or pus were cultured at 37 degrees C on 2% Ogawa and BBL MGIT. Acid-fast organisms were recovered on MGIT within 4 to 12 days, while 2% Ogawa medium failed to recover acid-fast bacteria. Using growth from the positive MGIT tube as inoculum, MycoBroth, 7H9 broth, 7H11.2% Ogawa supplemented with or without iron complexes, and blood agar were inoculated and cultured at 30 and 37 degrees C. Growth at 30 and 37 degrees C was seen with MycoBroth, 7H9, hemin (60 microM) or ferric ammonium citrate (15 mg/ml) supplemented 7H11 and blood agar as well as 7H11 supplemented with factor X. Growth at 30 degrees C only was observed for ferric ammonium citrate supplemented 7H9 and 2% Ogawa. Generally, growth at 30 degrees C was better than that at 37 degrees C in all media. No growth at either temperature was observed with hemin or factor X supplemented 2% Ogawa. With respect to the biochemical characterization, the isolate was negative for niacin, nitrate reduction, urease, arylsulfatase, Tween 80 hydrolysis, catalase, 68 degrees C catalase, acid phosphatase, and tellurite reduction, while strongly positive for neutral red test. Sequencing of the 16S rRNA gene showed the isolate to be consistent with Mycobacterium haemophilum. Based on the composite characterization, the isolate was identified as M. haemophilum. This is the second case report of M. haemophilum infection in Japan in the literature.
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PMID:[Bacteriological features of Mycobacterium haemophilum isolated from skin lesions in an immunodeficient patient]. 1521 60

Two antifungal peptides (designated alpha- and beta-basrubrins) with molecular masses of 4-5 kDa and distinct N-terminal sequences, and a peptide and a protein with N-terminal sequences resembling heat shock protein (hsp) and serine-threonine kinase, respectively, were isolated from seeds of the Ceylon spinach Basella rubra. The purification procedure entailed saline extraction, (NH4)2SO4 precipitation, ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose, and FPLC-gel filtration on a Superdex peptide column. alpha- and beta-basrubrins inhibited mycelial growth in Botrytis cirerea with an IC50 value of 7.5 and 14.7 microM, respectively, Mycosphaerella arachidicola with an IC50 of 12.4 and 6.9 microM, and Fusarium oxysporum with an IC50 of 5.8 and 6.2 microM. Neither alpha-basrubrin nor beta-basrubin exhibited DNase, RNase, lectin or protease activity, indicating that their antifungal action is not due to these activities. HIV-1 reverse transcriptase was inhibited by alpha- and beta-basrubrins with an IC50 of 246 and 370 microM, respectively. Translation in rabbit reticulocyte lysate was inhibited by alpha- and beta-basrubrins with an IC50 of 400 and 100 nM. The heat shock protein-like peptide and serine-threonine kinase-like protein exhibited a molecular mass of 3 and 30 kDa, respectively. They inhibited neither translation in a rabbit reticulocyte system at concentrations up to 50 microM nor HIV-1 reverse transcriptase activity at concentrations up to 400 microM. They did not exert antifungal activity toward B. cinerea, M. arachidicola, and F. oxysporum when tested up to 16 microg. None of the aforementioned proteins demonstrated DNase, RNase, protease or lectin activity.
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PMID:Antifungal peptides, a heat shock protein-like peptide, and a serine-threonine kinase-like protein from Ceylon spinach seeds. 1524 82

In order to develop orally active CCR5 antagonists, we investigated 1-benzoxepine derivatives containing new polar substituents, such as phosphonate, phosphine oxide or pyridine N-oxide moieties, as replacements for the previously reported quaternary ammonium moiety. Among these compounds, the 2-(alpha-hydroxybenzyl)pyridine N-oxide 5e exhibited moderate CCR5 antagonistic activity and had an acceptable pharmacokinetic profile in rats. Subsequent chemical modification was performed and compound (S)-5f possessing the (S)-configuration hydroxy group was found to be more active than the (R)-isomer. Replacement of the 1-benzoxepine ring with a 4-methylphenyl group by a 1-benzazepine ring with a 4-[2-(butoxy)ethoxy]phenyl group enhanced the activity in the binding assay. In addition, introduction of a 3-trifluoromethyl group on the phenyl group of the anilide moiety led to greatly increased activity in the HIV-1 envelope-mediated membrane fusion assay. In particular, compound (S)-5s showed the most potent CCR5 antagonistic activity (IC(50)=7.2 nM) and inhibitory effect (IC(50)=5.4 nM) in the fusion assay, together with good pharmacokinetic properties in rats.
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PMID:Orally active CCR5 antagonists as anti-HIV-1 agents 2: synthesis and biological activities of anilide derivatives containing a pyridine N-oxide moiety. 1525 2


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