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PubMed1989

Unusual anodic migrating isoamylase differentiates selected malignant from nonmalignant ascites.

Ascitic fluid from nine patients with nonmalignant ascites and nine patients with malignant ascites was subjected to isoamylase analysis. Unusual isoamylase bands that migrate to the anode were demonstrated in seven of eight patients with ovarian carcinoma and in one patient with gastric carcinoma. In no case of nonmalignant ascites was anodic isoamylase found, despite the presence of normal amylase in all samples. This is the first report of anodic isoamylase from ascitic fluid in gastric carcinoma and the first series comparing isoamylase patterns in malignant and nonmalignant ascites. Anodic isoamylase on electrophoresis of ascitic fluid may prove to be useful as a tumor marker in differentiating selected malignancies from nonmalignant ascites.

Amylases↗
PubMed2005

Analysis of differential selective forces acting on the coat protein (P3) of the plant virus family Luteoviridae.

The coat protein (CP) of the family Luteoviridae is directly associated with the success of infection. It participates in various steps of the virus life cycle, such as virion assembly, stability, systemic infection, and transmission. Despite its importance, extensive studies on the molecular evolution of this protein are lacking. In the present study, we investigate the action of differential selective forces on the CP coding region using maximum likelihood methods. We found that the protein is subjected to heterogeneous selective pressures and some sites may be evolving near neutrality. Based on the proposed 3-D model of the CP S-domain, we showed that nearly neutral sites are predominantly located in the region of the protein that faces the interior of the capsid, in close contact with the viral RNA, while highly conserved sites are mainly part of beta-strands, in the protein's major framework.

Capsid Proteins↗
PubMed1989

Graduated resistance to G418 leads to differential selection of cultured mammalian cells expressing the neo gene.

The effects of Geneticin (G418) selection on the growth and survival of cultured mammalian cells expressing the neomycin-resistance gene (neo) were studied by the analysis of cell clones from two retroviral neo vector-infected populations. We found a correlation between the neo expression level and growth rates in medium containing varying G418 concentrations. This relationship permits the use of differential selection schemes for the isolation of rare cells with increased expression. Comparison, by clone sampling, of vector-positive populations before and after selection with a G418 concentration in the range usually used for selection, showed different expression level and vector copy number distributions for the population infected with the vector of lower LTR activity, but not for the other. Such biasing effects of G418 selection may be important when selected cells are used for quantitative studies of gene expression.

Animals↗
PubMed1973

Apparent differential selection at an isozyme locus between queens and workers of the ant Aphaenogaster rudis.

The frequencies of two alleles at a cathodal malate dehydrogenase locus in populations of A. rudis were studied in 47 colonies from three localities in Georgia and one in New Jersey. The male gene frequencies of the New Jersey and one Georgia locality differ significantly. All the queens at one Georgia locality were heterozygotes. This genotypic distribution differs strongly from that of the workers, in which approximately equal numbers of heterozygotes and homozygotes were found. The heterozygote excess among queens but not their worker progeny suggests differential selection between these castes. This study also shows that rudis colonies consist of a single, once-mated queen and her worker progeny.

Alleles↗
PubMed1987

Differential selectivity of endothelium-derived relaxing factor and nitric oxide in smooth muscle.

The selectivity of endothelium-derived relaxing factor (EDRF) and nitric oxide (NO) on smooth muscle relaxation was examined and compared. EDRF released from was examined and compared. EDRF released from bovine pulmonary arterial endothelium (BPAE) in culture and NO were superfused over vascular, tracheal, gastrointestinal and uterine smooth muscle. EDRF relaxed vascular smooth muscle but not tracheal, gastrointestinal or uterine smooth muscle. NO relaxed vascular and gastrointestinal smooth muscle but not tracheal or uterine smooth muscle. There was a differential selectivity between the relaxant effect of EDRF and NO on smooth muscle.

Animals↗
PubMed2025

Phylogeny, chromosomal mapping and expression analyses of wheat CLAVATA pathway components suggest differential selection on receptor-like kinases, CLEs and T3 WOXes.

Ensuring continuous global food security is a major challenge of the 21st century. Wheat contributes approximately 20% of the total calories consumed by humans, and an estimated 60% increase in production will be required by 2050 to meet forecast global demand. In cereals like wheat, inflorescence (ear) size and branching patterns determine the number of flowers (florets) and grains produced, and these aspects of plant architecture are regulated by the activity of stem cells in the growing shoot tips. CLAVATA peptide and receptor-like kinase signalling regulates angiosperm stem cell activity, and as changes in CLAVATA function can improve crop yields, CLAVATA is a key target for reverse engineering. Here, we identify components of the wheat CLAVATA pathway using genome searches against Triticum aestivum and its wild relatives Triticum turgidum ssp. durum, Triticum turgidum ssp. dicoccoides, Triticum urartu and Aegilops tauschii. Using phylogenetic and synteny analysis, we determine the relationship between homoeologues and infer patterns of gene family evolution. Whilst CLAVATA1, BARELY ANY MERISTEM, RECEPTOR-LIKE PROTEIN KINASE 2, CORYNE and CLAVATA2 receptor-like kinase homologues are mainly present as single genome copies as in other grasses, CLAVATA3-like but not TRACHEARY ELEMENT DIFFERENTIATION FACTOR (TDIF)-like peptide encoding genes and WUSCHEL-LIKE HOMEOBOX (WOX) genes have expanded copy numbers with many gene gains and losses during evolution. Our results highlight wheat CLAVATA pathway components for reverse genetic analysis and indicate potential differential selection on wheat receptor-like kinases, their peptide ligands and WOXes.

Triticum↗
PubMed1989

Antiproliferative effect of IFN-gamma in immune regulation. III. Differential selection of TH1 and TH2 murine helper T lymphocyte clones using recombinant IL-2 and recombinant IFN-gamma.

Supernatants collected after primary or secondary stimulation of spleen cells contain different arrays of lymphokines. Primary supernatants from spleen cells stimulated with Con A or allogeneic spleen cells (MLC-SF) contain IL-2 but little IL-4 or IGN-gamma; in contrast, secondary MLC-SF contains IL-2 as well as substantial IL-4 and IFN-gamma. Our laboratory previously had always used secondary MLC-SF for cloning T cells, and had routinely obtained TH1 helper T lymphocyte clones. In the present study, when primary Con A-SF was used as source of growth factors, TH2 and not TH1 clones were preferentially derived. Considering the possibility that IFN-gamma may be one important factor in determining whether TH1 or TH2 clones are preferentially obtained, clone derivation was then performed either in the presence of rIL-2 or rIL-2 plus rIFN-gamma. The majority of clones derived using rIL-2 alone were TH2 cells, whereas the majority of clones derived using rIL-2 plus rIFN-gamma were TH1 cells. Using either procedure, some clones were obtained that produced IL-2, IL-4, and IFN-gamma. These data are consistent with our previous observations that IFN-gamma inhibits the proliferation of TH2 but not TH1 clones, and suggest that the presence of IFN-gamma during an immune response would result in the preferential expansion of helper T lymphocytes of the TH1 phenotype. Our procedure for the differential selection of TH1 and TH2 clones reactive with the same Ag should be useful for designing in vitro systems for studying the function of these cell subsets in specific immune responses.

Animals↗
PubMed1989

Liquid and solid selective differential media for the detection and enumeration of L. monocytogenes and other Listeria spp.

A selective and differential medium (PALCAM agar) was elaborated for the isolation and enumeration of Listeria monocytogenes. PALCAM is based on Columbia agar with 0.05% glucose made selective by the addition of 0.001% polymyxin B, 0.0005% acriflavin, 1.5% lithium chloride and 0.002% ceftazidime. The diagnostic traits were attained by the incorporation of (i) 0.08% aesculin and 0.05% ferric salt; and (ii) 1% mannitol plus 0.008% phenol red. PALCAM recovered test strains of L. monocytogenes and other Listeria spp quantitatively and suppressed most other bacteria of common occurrence in fresh food. L. monocytogenes colonies were approximately 2 mm grey-green with a black sunken centre and a black halo on a cherry-red background. The occasional Enterococcus or Staphylococcus strains developing on the medium gave rise to grey colonies with a brown-green halo or yellow colonies with a yellow halo. PALCAM was the preferred medium out of 13 tested Listeria selective agars in current use. A similar differential enrichment broth, L-PALCAMY was developed based on peptone yeast extract broth with 2.5% egg yolk emulsion. The diagnostic traits and inhibitors used in this medium were the same as in PALCAM agar, through in different concentrations. Growth rate and cellcrop of L. monocytogenes in L-PALCAMY were of the same order as in Columbia broth. The growth of the majority of other bacteria of common occurrence in fresh foods was inhibited. The medium recovered L. monocytogenes more effectively from severely contaminated food than other current enrichment media.

Colony Count, Microbial↗
PubMed1982

Selective differential human blood bilayer media for isolation of Gardnerella (Haemophilus) vaginalis.

New selective and differential human blood bilayer agar media with Tween 80 (HBT medium) or without Tween 80 (HB medium), developed for the isolation of Gardnerella (Haemophilus) vaginalis, permitted significantly higher G. vaginalis isolation rates than have been obtained for other media used for this purpose. HB medium consists of a basal layer of Columbia agar base containing colistin and naladixic acid with added amphotericin B and an overlayer of the same composition plus 5% human blood. HBT agar also contains Proteose Peptone No. 3 (Difco Laboratories) and Tween 80 in the basal layer and the overlayer. Both Tween 80 and the bilayer composition enhanced G. vaginalis production of human blood hemolysis, permitting detection of this organism even in the presence of heavy growth of other vaginal flora. The use of HB or HBT medium thus permitted the demonstration that G. vaginalis was present in vaginal fluid from a large percentage (up to 68%) of normal women. However, the concentration of G. vaginalis was found by semiquantitative analysis to be significantly higher in vaginal fluid from women with nonspecific vaginitis than in fluid from normal women.

Bacteriological Techniques↗
PubMed1983

Differential selectivity of 5-fluorouracil and 5'-deoxy-5-fluorouridine in cultured human B lymphocytes and mouse L1210 leukemia.

The role of differential metabolic activation of a 5-fluorouracil (FU) prodrug, 5'-deoxy-5-fluorouridine (dFUR), in achieving selective cytotoxicity was investigated in cultured human (dFUR), in achieving selective cytotoxocity was investigated in cultured human B lymphocytes and murine leukemia L1210 cells. B cells were cross-sensitive to FU and dFUR. On the other hand, leukemia L1210 cells were sensitive to FU but resistant to dFUR. The difference in the biological activities of FU and dFUR in B and L1210 cells correlated with (a) the metabolism of dFUR to FU by intact B (60% conversion) and L1210 (no conversion) cells, and (b) the phosphorylase activity of B (660 nmoles converted in 2 hr per mg protein) and L1210 (undetectable) cells. The intracellular metabolism of FU and dFUR was studied using a reversed-phase ion-pair high pressure liquid chromatographic assay. FU and dFUR shared similar metabolic pathways in B cells; their anabolites included FU ribose and deoxyribose nucleosides and nucleotides. In L1210 cells, FU was anabolized to 5-fluorouridine triphosphate and 5-fluorodeoxyuridine monophosphate, whereas dFUR was present mainly as the unchanged drug. Further metabolism studies using dFUR with tritium label in either the FU moiety or the altered sugar moiety established that the metabolic pathway of dFUR to cytotoxic FU anabolites in the B cells was via phosphorolysis to FU. These data indicate that, on a cellular level, an FU prodrug such as dFUR, which is activated by cytosolic enzyme, has a different selectivity from that of FU, and that the basis of differential selectivity is the initial phosphorolysis to FU.

Animals↗
PubMed2006

A new approach for enhancing differential selectivity of drugs to cancer cells.

The degree to which anticancer agents selectively target cancer cells is a key determinant in successful therapeutic outcomes. Inhibitors of the Hsp90 molecular chaperone represent an important new class of anticancer agents. We propose here a novel mechanism by which physiochemical properties of Hsp90 inhibitors can be optimized to increase selectivity towards cancer cells. The basis for this approach relies on differential intracellular pH gradients that have been shown to exist between normal and transformed cells. Five Hsp90 inhibitors containing basic or neutral properties were evaluated in antiproliferation assays using cells with variable lysosomal pH. Inhibitors with basic functionalities had reduced activity in cells with normal (low) lysosomal pH but showed significantly greater activity in cells with abnormally elevated lysosomal pH (similar to what has been recorded in many types of cancer cells). Conversely, such selectivity enhancement was not observed for neutral inhibitors. The mechanistic basis for the observed selectivity was demonstrated quantitatively by determining the concentration of inhibitors within relevant intracellular compartments. Collectively, these findings suggest that Hsp90 inhibitors with optimal basicity and physicochemical properties have enhanced selectivity toward cancer cells than their neutral counterparts. It is anticipated that these findings may be applicable to other classes of anticancer agents for improvement of differential selectivity.

Antineoplastic Agents↗
PubMed1990

A new selective, differential agar medium for isolation of Vibrio cholerae O1: PMT (polymyxin-mannose-tellurite) agar.

A new selective and differential agar medium, polymyxin-mannose-tellurite (PMT) agar was devised to differentiate easily colonies of Vibrio cholerae O1 from those of V. cholerae non-O1. The differentiation between colonies of the two vibrios is based on mannose-fermentation. Colonies of V. cholerae O1 on the agar are agglutinated with O1 antiserum of V. cholerae much more easily than those on thiosulfate-citrate-bile salts-sucrose (TCBS) agar.

Agar↗
PubMed2006

A selective differential medium for Lactobacillus plantarum.

The quantification of exogenous lactobacilli in faecal samples is frequently required for the evaluation of the intestinal colonization by probiotic bacteria. In this study, a selective and differential medium, designated LPSM, was developed for the culture of exogenous Lactobacillus plantarum. In quantitative assays, LPSM showed a sensitivity similar to those of enriched and Lactobacillus-adapted media. The presence of ciprofloxacin made LPSM inhibitory to most intestinal bacteria, including endogenous acid lactic bacteria, whereas exogenous L. plantarum strains grew producing a yellow color caused by acid production from sorbitol in the presence of bromocresol purple. The results showed that LPSM is suitable for detection and enumeration of L. plantarum in faecal samples.

Animals↗
PubMed2006

Directed growth and selective differentiation of neural progenitor cells on micropatterned polymer substrates.

Directional growth and differentiation of adult rat hippocampal progenitor cells (AHPCs) were investigated on micropatterned polymer substrates in vitro. Astrocytes or AHPCs cultured on micropatterned polystyrene substrates chemically modified with laminin exhibited over 75% alignment in the groove direction. AHPCs co-cultured with astrocytes preferentially acquired neuronal morphology, with nearly double the percentage of cells expressing class III beta-tubulin on the micropatterned half of the substrate, as opposed to the planar half of the substrate, or compared to those growing in the absence of astrocytes. This indicates that substrate three-dimensional topography, in synergy with chemical (laminin) and biological (astrocytes) guidance cues, facilitates neuronal differentiation of the AHPCs. Through multi-dimensional cell-cell interactions, this environment provides spatial control selectively enhancing neuronal differentiation and neurite alignment on topographically different regions of the same substrate. Integrating these cues is important in understanding and controlling neural stem cell differentiation and designing scaffolds for guided nerve regeneration.

Animals↗
PubMed2005

ADH enzyme activity and Adh gene expression in Drosophila melanogaster lines differentially selected for increased alcohol tolerance.

In Drosophila melanogaster, alcohol dehydrogenase (ADH) activity is essential for ethanol tolerance, but its role may not be restricted to alcohol metabolism alone. Here we describe ADH activity and Adh expression level upon selection for increased alcohol tolerance in different life-stages of D. melanogaster lines with two distinct Adh genotypes: Adh(FF) and Adh(SS). We demonstrate a positive within genotype response for increased alcohol tolerance. Life-stage dependent selection was observed in larvae only. A slight constitutive increase in adult ADH activity for all selection regimes and genotypes was observed, that was not paralleled by Adh expression. Larval Adh expression showed a constitutive increase, that was not reflected in ADH activity. Upon exposure to environmental ethanol, sex, selection regime life stage and genotype appear to have differential effects. Increased ADH activity accompanies increased ethanol tolerance in D. melanogaster but this increase is not paralleled by expression of the Adh gene.

Adaptation, Physiological↗
PubMed2001

Differential selection of multidrug efflux mutants by trovafloxacin and ciprofloxacin in an experimental model of Pseudomonas aeruginosa acute pneumonia in rats.

The ability of trovafloxacin and ciprofloxacin to select efflux mutants in vivo was studied in a model of acute Pseudomonas aeruginosa pneumonia in rats. Twelve hours after intratracheal inoculation of 10(6) CFU of P. aeruginosa strain PAO1 enmeshed in agar beads, two groups of 12 rats were treated by three intraperitoneal injections of each antibiotic given every 5 h. Dosing regimens were chosen to obtain a comparable area under the concentration-time curve from 0 to infinity/MIC ratio of 27.9 min for trovafloxacin (75 mg/kg of body weight) and of 32.6 min for ciprofloxacin (12.5 mg/kg). Twelve rats were left untreated and served as controls. Rats were sacrificed 12 h after the last injection (34 h after infection) for lung bacteriological studies. Selection of resistant bacteria was determined by plating lung homogenates on Trypticase soy agar plates containing antibiotic. In untreated animals, the frequency of resistant colonies was 10-fold higher than in agar beads. Compared to controls, both treatment regimens resulted in a 2-log reduction of lung bacterial load. The frequency of resistant colonies was 10-fold less with trovafloxacin than with ciprofloxacin at twice the MIC (7.4 x 10(-5) versus 8.4 x 10(-4), respectively) (P < 0.05) and at four times the MIC (6.2 x 10(-4) versus 5.0 x 10(-5), respectively) (P < 0.05). A multidrug resistance phenotype typical of efflux mutants was observed in all 41 randomly tested colonies obtained from treated and untreated rats. In agreement with in vitro results, trovafloxacin and ciprofloxacin preferentially selected MexCD-OprJ and MexEF-OprN overproducers, respectively. These results demonstrate the differential ability of trovafloxacin and ciprofloxacin to select efflux mutants in vivo and highlight the rapid emergence of those mutants, even without treatment.

Acute Disease↗
PubMed2006

Regulation of cardiomyocyte signaling by RGS proteins: differential selectivity towards G proteins and susceptibility to regulation.

Many signals that regulate cardiomyocyte growth, differentiation and function are mediated via heterotrimeric G proteins, which are under the control of RGS proteins (Regulators of G protein Signaling). Several RGS proteins are expressed in the heart, but so far little is known about their function and regulation. Using adenoviral gene transfer, we conducted the first comprehensive analysis of the capacity and selectivity of the major cardiac RGS proteins (RGS2-RGS5) to regulate central G protein-mediated signaling pathways in adult ventricular myocytes (AVM). All four RGS proteins potently inhibited Gq/11-mediated phospholipase C beta stimulation and cell growth (assessed in neonatal myocytes). Importantly, RGS2 selectively inhibited Gq/11 signaling, whereas RGS3, RGS4 and RGS5 had the capacity to regulate both Gq/11 and Gi/o signaling (carbachol-induced cAMP inhibition). Gs signaling was unaffected, and, contrary to reports in other cell lines, RGS2-RGS5 did not appear to regulate adenylate cyclase directly in AVM. Since RGS proteins can be highly regulated in their expression by many different stimuli, we also tested the hypothesis that RGS expression is subject to G protein-mediated regulation in AVM and determined the specificity with which enhanced G protein signaling alters endogenous RGS expression in AVM. RGS2 mRNA and protein were markedly but transiently up-regulated by enhanced Gq/11 signaling (alpha1-adrenergic stimulation or Galphaq* overexpression), possibly by a negative feedback mechanism. In contrast, the other negative regulators of Gq/11 signaling (RGS3-RGS5) were unchanged. Endogenous RGS2 (but not RGS3-RGS5) expression was also up-regulated in cells with enhanced AC signaling (beta-adrenergic or forskolin stimulation). Taken together, these findings suggest diverse roles of RGS proteins in regulating myocyte signaling. RGS2 emerged as the only selective and highly regulated inhibitor of Gq/11 signaling that could potentially become a promising target for ameliorating Gq/11-mediated signaling and growth.

Adenoviridae↗
PubMed1994

[Development of a selective differential medium for the isolation of Corynebacterium urealyticum (group D-2)].

BACKGROUND: We have developed a new selective culture medium for the isolation of C. urealyticum, with the aim of improving and making easier the isolation and identification of this microorganism. MATERIAL AND METHODS: The medium is based on components similar to other media, usually used for diagnosis of urinary tract infections, also containing glucose, urea, phenol red, polysorbate 80 (Tween 80), polymixin B, amphotericin B, nalidixic acid and lyncomycin. The medium was tested in 65 clinical isolates and three type strains, and in 533 clinical samples of urine. RESULTS: All 65 clinical strains and 3 reference strains of C. urealyticum tested grew faster on this medium than on blood agar. E. coli, Klebsiella spp., Enterobacter spp., Citrobacter spp., M. morganii, Proteus spp., S. aureus, Enterococcus spp. and Corynebacterium spp. did not grow in the selective agar. S. epidermidis and Streptococcus spp. grew in less than 10% of cases, P. aeruginosa in 29.2% and Serratia spp. in 41.7%. The colonies were always easily differentiated from C. urealyticum. In the studies performed on 553 clinical samples from patients with urinary tract infections, six infections by C. urealyticum were detected. The growth of all strains being faster on this medium than on blood-agar. CONCLUSIONS: This new selective medium may be a valuable tool for diagnosis of UTIs caused by C. urealyticum in patients with retard risk factors.

Bacteria↗