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PubMed1992

Human immunodeficiency virus type 1-infected HL-60 cells are capable of both monocytic and granulocytic differentiation.

We have used the human myelomonocytic cell line HL-60 as a model system to determine whether human immunodeficiency virus type 1 (HIV-1) infection affects differentiation of myeloid progenitor cells. HL-60 cells were infected with three HIV-1 isolates (IIIB, NL4-3 and PM213). HIV-1 antigen expression and cytopathicity in HL-60 cells infected with each of the three isolates was delayed by approximately 15 days as compared to those in the prototypic T cell line, H9. Chronically infected HL-60 cells and clonal lines derived from them were treated with dimethyl formamide (DMF) and induced to differentiate into granulocytes. Approximately the same percentage of these cells as of DMF-treated, uninfected HL-60 cells differentiated. Superoxide production by infected and uninfected DMF-induced cells was similar. Likewise, approximately the same percentage of cells in infected and uninfected cultures became adherent and were positive for non-specific esterase when monocytic differentiation was induced. The data demonstrate that HL-60 cells infected with HIV-1 are capable of morphological and functional granulocytic and monocytic differentiation.

CD4 Antigens↗
PubMed1992

Characterization of two variants of Panolis flammea multiple nucleocapsid nuclear polyhedrosis virus.

The baculovirus Panolis flammea multiple nucleocapsid nuclear polyhedrosis virus (PfMNPV) was originally isolated from a natural virus epizootic and shown to consist of a mixture of variants. Two subclasses of variants (PfMNPV A and B) were identified by Southern blot hybridization, their polyhedrin genes being located on different restriction fragments. The proportion of the A and B variants changed according to the larval host in which the virus was propagated; PfMNPV(B) predominated in P. flammea but PfMNPV(A) was predominant in Mamestra brassicae. Bioassays of the two pure virus variants in M. brassicae larvae have shown the LD50 values to be 4610 polyhedron inclusion bodies (pibs) for PfMNPV(A) and 5937 pibs for PfMNPV(B). Genomic DNA from the two variants was compared using restriction endonuclease analysis, and dot blot and Southern blot hybridization. Reciprocal quantitative dot blot hybridization analysis in 50% formamide showed PfMNPV(A) and PfMNPV(B) to be only distantly related to Autographa californica MNPV (less than 1%) and more closely related to M. brassicae MNPV (21 to 26%). The two PfMNPV variants exhibited a very high degree of identity to each other (nearly 100%) and therefore are very closely related. This was confirmed by physical mapping of the virus genomes. The nucleotide sequence of the polyhedrin gene of PfMNPV(B) was determined and compared with the published DNA sequences of other polyhedrin genes.

Animals↗
PubMed1978

An electron microscopic study of the location of peptidoglycan in group A and C streptococcal cell walls.

The morphological appearance of deproteinized Group A and C streptococcal walls after treatment by different procedures extracting teichoic acids and polysaccharides (formamide, hydrochloric acid, nitrous acid, trichloroacetic acid, sulphuric acid, sodium hydroxide and sodium deoxycholate) was compared with the content of teichoic acids and polysaccharides remaining in the treated walls. All procedures extracted teichoic acids almost completely, but polysaccharides were extracted to various degrees. The ultrastructural appearance of walls after these extractions still exhibited the triple-layered wall profile; only a reduction of thickness of the wall and of electron density of the layers occurred. There was no direct correlation between the reduction of rhamnose content and thickness of walls. The ultrastructural localization of peptidoglycan in the streptococcal walls was explored by means of the indirect immunoferritin technique using anti-peptidoglycan antibodies isolated from anti-Group A-variant antisera. Ferritin particles were bound predominantly to filamentous structures which protruded from both surfaces of peptidoglycan fragments and isolated walls. Peptidoglycan was also detected on the filamentous protrusions of whole cocci. These results contradict models of the streptococcal wall in which peptidoglycan forms the innermost layer and support a mosaic structure in which peptidoglycan forms a network of the peptidoglycan-polysaccharide complex.

Antibodies, Bacterial↗
PubMed1979

Characterization of the autolytic enzymes of Clostridium perfringens.

Clostridium perfringens and isolated walls of this organism autolysed rapidly when incubated in buffer at pH 7.0 with the release of free-reducing groups but no N-terminal amino acids. The predominant autolytic enzyme was an endo-beta-N-acetylglucosaminidase, and an endo-beta-N-acetylmuramidase was also present. The autolytic enzymes could be solubilized by extraction of the organisms with 5 M-LiCl and would then subsequently bind to and rapidly lyse walls of Micrococcus luteus and, more slowly, formamide-extracted walls of C. perfringens and walls of Bacillus subtilis. Lysis of C. perfringens walls by these extracted enzymes could not be demonstrated.

Acetylglucosaminidase↗
PubMed1976

Lability of RNA from the large cytoplasmic ribosomal subunit of the protozoon Crithidia oncopelti.

Cytoplasmic ribosomalRNA extracted from Crithidia oncopelti and analysed by gel electrophoresis at 4 degrees C consisted of two components, with molecular weights (relative to E. coli rRNA) of 1-30 X 10(6) and 0-83 X 10(6) daltons, present in equimolar amounts. On heating briefly at 51 degrees C followed by rapid cooling, the 1-30 X 10(6) RNA completely dissociated into two components of molecular weights 0-70 X 10(6) and 0-56 X 10(6) (present in equimolar amounts). Fifty per cent dissociation of the molecule occurred at 28 degrees C. That the integrity of the RNA molecule at low temperatures is maintained by its secondary structure was confirmed by electrophoresis under denaturing conditions (98%, v/v, formamide). To account for these phenomena, latent cleavage of the molecule in vivo is proposed.

Animals↗
PubMed1976

Regulatory properties of an inducible aliphatic amidase in a thermophilic bacillus.

A thermophilic bacillus growing on acetamide as both carbon and nitrogen sources produces an inducible amidase. This amidase hydrolysed the following amides in decreasing order or activity, in comparison with acetamide (1.00): propionamide (0.97), fluoroacetamide (0.84), formamide (0.35) and glycinamide (0.12). Cyanoacetamide, dimethylacetamide, dimethylformamide and urea also induced the synthesis of the amidase, but were not substrates of the enzyme. Studies with protoplasts suggest that the amidase is located in the cytoplasm. Glucose strongly inhibited amidase synthesis; and limiting nitrogen did not release this inhibition. Urea strongly inhibited amidase activity in a competitive manner; but the inhibition caused by iodoacetamide and cyanoacetamide was non-competitive. Both thioacetamide and thiourea were effective inhibitors of enzyme induction. Bacteria grown on a succinate-minimal medium exhibited a lag in amidase synthesis, which could be eliminated by decreasing the concentration of succinate. Acetate- or pyruvate-grown cultures behaved similarly, while those grown on alanine or glutamate exhibited no lag in enzyme induction. In the mutant strain E21, repression of amidase synthesis by glucose was much less evident and no lag for induction was apparent with any of the other carbon sources mentioned.

Acetamides↗
PubMed1996

PCR-LIS-SSCP (Low ionic strength single-stranded conformation polymorphism)--a simple method for high-resolution allele typing of HLA-DRB1, -DQB1, and -DPB1.

We have developed a simple and efficient procedure with which to form single-stranded DNA [ssDNA] and then applied HLA-DRB1, -DQB1, and -DPB1 allele typing. This method is referred to as low ionic strength single-stranded conformation polymorphism (LIS-SSCP), and is based on the diversity in the electrophoretic mobility of ssDNA formed by heat denaturation in low ionic strength solutions. This method detected DNA polymorphisms, including point mutations at a variety of positions in the DNA fragments of the HLA-DRB1, -DQB1, and -DPB1 genes. Under our experimental conditions, stable ssDNA could be kept at room temperature > or = 5 hr without having been cooled on ice immediately after heat denaturation. A total of 41 HLA-DRB1, 14 HLA-DQB1, and 17 HLA-DPB1 alleles from 220 healthy people were analyzed using a combination of PCR-LIS-SSCP with group-specific amplification. All of the alleles analyzed were discriminated among the DRB1, DQB1, and DPB1 groups except for DPB1*0402 and 0201. The efficiency of ssDNA formation using the LIS-SSCP procedure was higher than that of the traditional formamide method, and the SSCP profiles were clearer than those of the original SSCP. This procedure is useful for screening new alleles as well as the donor-recipient molecular matching of HLA class II genes. It is simple, rapid, and cost effective, requiring neither radioisotopes nor enzymes to confirm the typing results of other methods.

Alleles↗
PubMed2002

Electric-field-induced ion evaporation from dielectric liquid.

A direct proof of ion field evaporation from dielectric liquids is presented. The flux of sodium ions ejected from the surface of an electrospray of formamide is measured using time-of-flight and retarding potential techniques. The electric field at the emitting surface is varied through the electrospraying parameters. We find that the evaporated ion current is a very steep function of the electric field.

Journal Article↗
PubMed1975

The occurrence and distribution of poly(a) ribonucleic Acid in soybean.

The occurrence and distribution of poly(A) sequences in the RNA of soybean (Glycine max var. Wayne) have been studied. Only one of the two species of AMP-rich RNA contains poly(A). D-RNA does not contain detectable poly(A) sequences. The TB-RNA is the poly(A) RNA in this system. At least a part (up to 50% or more) of the mRNA in polyribosomes contains a poly(A) sequence. The poly(A) RNA is heterodisperse in size but has a mean size of approximately 18S (2,000 nucleotides) in urea and formamide gels. The poly(A) fragment resulting from ribonuclease A and T(1) digestion migrates as a broad band overlapping the 4 to 5.8S regions of the gels with a mean size of somewhat greater than 5S. No evidence was found for the occurrence of a discrete oligo(A) fragment in the poly(A) RNA; however, oligonucleotides which migrate faster than the poly(A) fraction were observed in preparations which were not bound to oligo(dT) cellulose prior to electrophoresis. This oligonucleotide region was enriched in AMP (up to about 65%) as would be expected after ribonuclease A and T(1) digestion.

Journal Article↗
PubMed1980

Partial purification and characterization of the mRNA for alpha-amylase from barley aleurone layers.

The poly(A)-containing mRNA from barley aleurone layers pretreated with gibberellic acid has been purified by phenol-chloroform extraction and repeated oligo[d(pT)]-cellulose chromatography. This RNA has been translated in both the wheat germ and reticulocyte lysate in vitro translation systems with greater than 50% of the synthesized protein being alpha-amylase. The mRNA for alpha-amylase has been further purified by dimethylsulfoxide-formamide-sucrose density gradient centrifugation and by gel electrophoresis. By these methods, its molecular weight has been determined to be 580,000.

Journal Article↗
PubMed1982

Cyanide-insensitive respiration in relation to growth of a low-temperature basidiomycete.

The cyanogenic low-temperature basidiomycete (Coprinus psychromorbidus Redhead and Traquair), unlike other cyanide-tolerant fungi, does not detoxify cyanide via formamide hydro-lyase. Instead, tolerance apparently depends on cyanide-insensitive respiration involving activity of the mitochondrial alternative oxidase. Respiration and growth of young mycelium that lacks alternative oxidase activity are blocked both by cyanide and 1 mum antimycin. When activity of the alternative oxidase is elicited in young mycelium by 0.05 mm cyanide, subsequent treatment with antimycin stimulates respiration and fails to halt growth. Older mycelium becomes tolerant coincidentally with the release of cyanide by the mycelium. Tolerant older mycelium in medium containing 0.05 to 1.0 mum antimycin grows at 30 to 45% of the control rate. Cyanide- and antimycin-tolerant growth and respiration are blocked by salicyl hydroxamic acid, an inhibitor of the alternative oxidase, and by rotenone, which inhibits ATP synthesis at site I.

Journal Article↗
PubMed1984

Determination of Solute Permeability in Chara Internodes by a Turgor Minimum Method : Effects of External pH.

The analysis of Sha'afi et al. (Sha'afi, Rich, Mickulecky, Solomon 1970 J Gen Physiol 55: 427-450) for determining solute permeability in red blood cells has been modified and applied to turgid plant cells. Following the addition of permeating solute to the external medium, a biphasic response of cell turgor can be measured with the pressure probe in isolated internodes of Chara corallina. After an initial decrease in turgor due to water flow (water phase), turgor increases due to the uptake of the solute (solute phase) until the original turgor is reattained. From the pressure/time course in the neighborhood of the minimum turgor, the permeability of the osmotic solute can be determined. The data obtained by the minimum method for rapidly permeating (ethanol, methanol) and slowly permeating (formamide, dimethylformamide) solutes are similar to those calculated from the half-time of pressure changes during the solute phase and to data obtained by other workers using radioactive tracers. The methods employing the pressure probe were applied to examine the effect of high pH (up to pH 11) on the membrane permeability. There appeared to be no effect of high pH on the permeability coefficients, reflection coefficients, and hydraulic conductivity.

Journal Article↗
PubMed2003

Ethyl 2-formamido-2-(4-iodobenzyl)-3-(4-iodophenyl)propionate and ethyl 2-(3-bromobenzyl)-3-(3-bromophenyl)-2-formamidopropionate.

The title compounds, C(19)H(19)I(2)NO(3) and C(19)H(19)Br(2)NO(3), are derivatives of alpha-aminoisobutyric acid with halogen substituents at the para and meta positions, respectively. The ethoxycarbonyl and formamide side chains attached to the C(alpha) atom of the molecule adopt extended and folded conformations, respectively. The crystal structures are stabilized by N-H.O, C-H.O, C-Br.O and C-I.O interactions.

Journal Article↗
PubMed1999

Influence of intermolecular interactions on multipole-refined electron densities.

This work examines the effect of intermolecular interactions on molecular properties derived from simulated X-ray diffraction data. Model X-ray data are computed from a superposition of ab initio molecular electron densities in the crystal, as well as from periodic crystal Hartree-Fock electron densities, for the hydrogen-bonded systems ice VIII, formamide and urea, as well as the weakly bound acetylene. The effects of intermolecular interactions on the electron density are illustrated at both infinite and finite data resolution, and it is concluded that multipole models are capable of quantitative retrieval of the interaction density, despite the known shortcomings of the radial functions in the model. Multipole refinement reveals considerable enhancement of the molecular dipole moment for hydrogen-bonded crystals, and negligible change in molecular second moments. Electric field gradients at H nuclei are significantly reduced in magnitude upon hydrogen bonding, and this change is also faithfully represented by the rigid pseudoatom model.

Journal Article↗
PubMed1987

Effect of skin pretreatment with vehicle alone or drug in vehicle on flux of a subsequently applied drug: results of hairless mouse skin and diffusion cell studies.

Clinical and in vitro evidence suggest that pretreatment of skin with a drug or vehicle can influence topical drug delivery. In this study, hairless mouse skin in diffusion cells was treated for 48 h with topical applications of vehicle alone (oleic acid (OA), isopropyl myristate, octanol (OCT), dimethylformamide, propylene glycol (PG), ethylene glycol (EG), formamide), or mixtures of OA and PG, or with 5-fluorouracil (5-FU) suspensions in each of these vehicles. Twenty-four hours after removing the initially applied agent, a standard suspension of theophylline in PG was applied to the skin surface and the flux of theophylline was determined over the next 48 h. Skin pretreatment with vehicle alone increased theophylline flux 1.6-(EG) to 122-fold (OCT) over control experiments in which the skins were not pretreated. Pretreatment with nonpolar vehicles with lower solubility parameters (OA, OCT, or mixed vehicles containing one of these) had the greatest effect on subsequent theophylline flux. Pretreatment with 5-FU in various vehicles caused a subsequent increased theophylline flux similar to the effect of vehicle alone, except for pretreatment with 5-FU in vehicles which did not have much effect themselves. In those instances, theophylline fluxes up to 16-fold over the effect of those vehicles alone were observed.

Animals↗
PubMed1986

Use of solubility parameters of drug and vehicle to predict flux through skin.

The solubilities of theophylline in, and fluxes through skin from, isopropyl myristate, octanol, dimethylformamide, propylene glycol, ethylene glycol, and formamide have been determined experimentally. Values for experimental permeability coefficients (Kp) corresponding to the respective fluxes were determined from, flux/solubility = Kp, which were then compared with values for the respective theoretical partition coefficients (PC) calculated from the known solubility parameters for the vehicles (delta v), theophylline (delta i) and skin (delta s). There was a good correlation for theoretical log PC - 2.52 = experimental log Kp for vehicles exhibiting solubility parameters in the range of delta v = 12-18 (cal/cm3)1/2. This allows relative fluxes to be determined from calculated theoretical partition coefficients and experimentally determined solubilities in that range. For vehicles or mixtures of vehicles exhibiting solubility parameters in the range of delta v = 8-12 (cal/cm3)1/2 large increases in fluxes and permeability coefficients, compared with those predicted from the results in the delta v = 12-18 (cal/cm3)1/2 range, were observed because of vehicle effects on the skin caused by the similarity in solubility parameters of those vehicles to that of skin. Qualitatively, fluxes and permeability coefficients were found to be inversely dependent on drug solubility in the vehicles with a minimum that corresponded approximately to the point where delta i = delta v.

Administration, Topical↗
PubMed1976

Quantitative chemical analyses and antigenic properties of peptidoglycans from Clostridium botulinum and other clostridia.

The cell wall peptodoglycans were isolated from Clostridium botulinum and some other species of the genus Clostridium by hot formamide extraction and their quantitative chemical composition and antigenic properties were determined. The petidoglycan of C. botulinum type E was found to be a diaminopimelic acid (DAP)-containing type composed of glucosamine, muramic acid, glutamic acid, alanine and DAP in the molar ratio of 0.76:0.78:1.00:1.88:0.81. All other types of C. botulinum and Clostridium sporogenes also belonged to the same peptidoglycan type. The peptidoglycans of Clostridium bifermentans and Clostridium histoloyticum contained DAP but they differed from those of C. botulinum in the molar ratio of alanine to glutamic acid. The peptidoglycan of Clostridium perfringens was composed of glutamic acid, alanine, DAP and glycine in the molar ratio of 1.00:1.64:0.94:0.90. On the other hand, the peptidoglycan of Clostridium septicum was found to contain lysine instead of DAP and the molar ratio was 1.00:1.41:0.96 for glutamic acid, alanine and lysine. In spite of the difference in amino acid composition of peptidoglycans among the clostridia, the quantitative precipitin test demonstrated that antiserum against C. botulinum type E peptidoglycan cross-reacted with the peptidoglycans from other clostridia as well as various types of C. botulinum.

Alanine↗
PubMed1980

Reassembly of the regularly arranged subunits in the cell wall os Lactobacillus brevis and their reattachment to cell walls.

The reassembly of tetragonally arranged subunits in the cell wall of Lactobacillus brevis and the reattachment of the subunits to cell wall fragments were investigated by electron microscopy. The subunits dissociated from the cell wall with guanidine hydrochloride (GHCl) reassembled into the same regular array as seen in native cell wall after dialysis against neutral buffer even in the absence of specific cations. The subunits could also reattach to the cell wall fragments from which they had been removed by treatment with GHCl, sodium dodecyl sulfate or cold trichloroacetic acid but not to those treated with hot formamide. Heterologous reattachment of the subunits occurred on cell wall fragments obtained from L. fermentum but not on those from L plantarum or L. casei subsp. casei. On the basis of these observations and chemical analyses of the cell wall fragments, the subunits of L. brevis appeared to be bound by hydrogen bonds to a neutral polysaccharide moiety in the cell wall but not to peptidoglycan or teichoic acid.

Cell Wall↗