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F D Gillin

Publications and source records attributed to F D Gillin.

At least 91 records · Page 5Linked to original sources
PubMed1981

Activation of the alternative complement pathway by Trichomonas vaginalis.

The mechanism underlying the lysis of Trichomonas vaginalis by normal human or guinea pig serum was investigated. The involvement of the complement system was demonstrated by the failure of human serum deficient in C3 or C8 to mediate parasite killing and by the ablation of lytic activity observed when fresh sera were heated at 56 degrees C or treated with ethylenediaminetetraacetate. Fixation of human C3 on the parasite surface was demonstrated by indirect immunofluorescence. The involvement of the alternative complement pathway was demonstrated (i) by the inability of properdin-depleted human serum to lyse T. vaginalis and (ii) by the normal killing observed with guinea pig serum lacking C4 and with normal human or guinea pig serum treated with ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid and Mg2+ to selectively inhibit the classical pathway.

Animals↗
PubMed1981

IgG antibody to Giardia lamblia detected by enzyme-linked immunosorbent assay.

A sensitive, reproducible enzyme-linked immunosorbent assay using unfixed, intact Giardia lamblia trophozoites as antigen is described. Employing this assay, we demonstrated that 81% of 59 symptomatic giardiasis patients and 12% of 17 uninfected control subjects had circulating IgG antibodies to G. lamblia. Eleven out of 15 patients tested serially had detectable antibody from 2 wk to 15 mo after therapy for acute infection. The prevalence of antibody in 197 unselected individuals in the Washington, D.C. area was 14%. Specificity of the antibodies was demonstrated by the ability of live G. lamblia trophozoites, but not Entamoeba histolytica or Trichomonas vaginalis trophozoites, to absorb the antibody activity. High titers of antibody were detected in 5 out of 7 patients with recurrent infection. The enzyme-linked immunosorbent assay described here may help to further characterize the antibody response to infection with G. lamblia.

Adult↗
PubMed1980

Attachment and short-term maintenance of motility and viability of Entamoeba histolytica in a defined medium.

Organic requirements for attachment to glass, elongation, and motility of Entamoeba histolytica, have been determined. The trophozoite, which has been grown axenically only in highly complex media with reduced oxygen tensions, remains rounded and detached when placed in a Tris-HCl buffered solution containing NaCl, KCl, MgClI, and CaCl2. A maintenance medium in which the amebae could attach to glass, elongate, and remain motile and viable for 12 to 24 h was devised with the addition of cysteine, ascorbic acid, bovine serum albumin, and the vitamin solution of medium NCTC No. 107. Tris-HCl was the most effective buffer tested and the optimal pH was 6.9 to 7.0. Survival, but attachment, of the amebae was decreased at osmolalities ranging between 110 and 180 milliosmoles/kg, whereas both functions were decreased above approximately 260 milliosmoles/kg. Bovine serum albumin, the most effective of the proteins tested, and the vitamin solution helped maintain attachment of some ameba strains, but were not required by other strains. The requirements for cysteine and ascorbic acid were absolute and highly specific. During incubation in the maintenance medium, cell volumes decreased. Sensitivity of the organisms to agglutination by concanavalin A, wheat germ agglutinin, soybean agglutinin and fucose binding protein remained unchanged.

Agglutination↗
PubMed1980

Attachment of Entamoeba histolytica to glass in a defined maintenance medium: specific requirement for cysteine and ascorbic acid.

Cysteine and ascorbic acid were previously shown to be required by Entamoeba histolytica trophozoites for attachment to glass, elongation, and ameboid movement as well as for short-term (12-24 h) survival in a balanced salt solution containing bovine serum albumin and a vitamin solution (Maintenance Medium 1). If the only function of cysteine and ascorbate was to decrease the redox potential, other reducing agents should be effective. However, the requirement for cysteine in the presence of ascorbic acid was highly specific. Equally effective were D- and L-cysteine; however, of many other compounds tested, only thioglycolic acid, ascorbic acid, or L-cystine (in decreasing order) were somewhat active. Under N2 atmosphere, cysteine and ascorbic acid were still required, although their concentrations could be halved. The ability to attach in the maintenance medium was irreversibly lost after only 5 min of cysteine-ascorbic acid deprivation; however, there was no decrease in viability when the amebae were transferred to growth medium within 30 min. Cysteine thiol groups in the medium were oxidized rapidly regardless of the concentration of ascorbic acid or the presence of amebae; however, ascorbic acid prolonged attachment of amebae.

Animals↗
PubMed1978

Clonal growth of Entamoeba histolytica and other species of Entamoeba in agar.

This is the first description of a method for growing axenized Entamoeba histolytica as colonies from single cells in agar suspension. Factors affecting the efficiency of colony formation included unknown characteristics of the amebal strain, age of cells used, and the type and concentration of agar employed. Colony formation was dependent upon filling deep vessels (culture tubes or tissue culture flasks) with agar, probably to maintain reduced oxygen tension, and upon solidifying the agar rapidly at 0 C. It was demonstrated in a study with the drug metronidazole that the agar colony method was useful for quantifying cell viability in drug testing. Eleven of 12 E. histolytica strains tested, as well as one Entamoeba terrapinae, one Entamoeba barreti, and 3 Entamoeba invadens strains formed colonies in agar suspension. E. histolytica-like amebae (Laredo type) and E. moshkovskii formed only tiny colonies in agar.

Agar↗
PubMed1978

Clonal growth of Entamoeba in agar: some applications of this technique to the study of their cell biology.

A new technique for growing single Entamoeba trophozoites into colonies in agar has been developed. This method depended upon axenic cultivation and utilized Diamond's new TYI-S-33 medium. The present paper describes several different types of experiment which have utilized the agar technique. a) Cloning. The isolation of clones from agar way easy and successful. Clones of the HM-1 strain did not differ in virulence for newborn hamster liver or in colony morphology or colony forming efficiency. b) Viability measurements. Colony forming efficiency (CFE) was proportional to the number of viable cells in a culture. Pilot studies with the amebacides, metronidazole and emetine, showed that the agar method should be useful in drug testing. Colchicine at high concentration inhibited clonal growth in a non-specific manner. c) E. histolytica HM-1 and E. invadens cells were rapidly killed by exposure to 42 degree C but survived relatively well at 0 degree C. d) Hemolysis. In a preliminary experiment HM-1 colonies did not produce halo's of hemolysis when grown in agar containing sheep red blood cells.

Agar↗
PubMed1976

Control of mutation frequency by bacteriophage T4 DNA polymerase. I. The CB120 antimutator DNA polymerase is defective in strand displacement.

The ts CB1200 (antimutator) mutation in bacteriophage T4 DNA polymerase increases the accuracy of DNA replication since it results in a decrease in the frequency of mutations in other phage genes. The CB120 polymerases differs from the wild type enzyme in the slow rate at which it copies templates where primer extension requries displacement of polynucleotides base-paired to the template strand, even in the presence of the T4 DNA unwinding protein (gene 32-protein). The ratio of nucleotides turned over (DNA-dependent conversion of deoxynucleoside triphosphate to deoxynucleoside monophosphate) to nucleotides stably incorporated into product is 10 to 100 times higher with the mutant than wild type enzyme, depending on the DNA used as the template. This high turnover rate may increase the efficiency of removal of noncomplementary nucleotides by the antimutator enzyme and is in agreement with the findings of Muzyczka et al, (Muzyczka, N., Poland, R. L., and Bessman, M. J. (1972) J. Biol, Cehm. 247, 7116-7122) with the L141 and L42 antimutator T4 DNA polymerases. Since the 3'- to 5'-exonuclease activity of the CB120 mutant polymerase is not higher than that of the wild type enzyme, it is suggested that the high turnover rate may result from increased opportunity to remove newly incorporated nucleotides due to the slow rate at which the mutant enzyme moves to the next template nucleotide. In the accompanying paper we show that the CB120 antimutator polymerase also initially selects incorrect nucleotides for incorporation less frequently than the wild type enzyme. Thus this antimutator polymerase appears to have both greater accuracy in nucleotide selection and an enhanced ability to remove incorrect nucleotides.

Coliphages↗
PubMed1976

Control of mutation frequency by bacteriophage T4 DNA polymerase. II. Accuracy of nucleotide selection by the L88 mutator, CB120 antimutator, and wild type phage T4 DNA polymerases.

The accuracy of nucleotide selection by wild type, L88 mutator, and CB120 antimutator T4 DNA polymerases has been compared by measuring both stable incorporation of complementary and noncomplementary nucleotides into polymer and the DNA-dependent conversion of deoxynucleoside triphosphate to monophosphate. The increased accuracy of the CB120 antimutator enzyme is shown by a ratio of utilization of incorrect to correct nucleotides with poly(dA)-poly(dT) as template which is only 10 to 30% of that of the wild type enzyme. In contrast, the ratio of incorrect to correct nucleotide utilized by the L88 mutator enzyme with this template was higher than that of the wild type enzyme, in agreement with the report of Hershfield (Hershfield, M.S. (1973) J. Biol, Chem. 248, 1417-1423). The antimutator, mutator, and wild type enzymes each have a much higher apparent Km for the noncomplementary nucleotides than for complementary nucleotides with this template. The L88 mutator polymerase has a higher "Km" for poly(dA)-poly(dT) than the wild type enzyme in reactions with both complementary and noncomplementary nucleotides. The antimutator polymerase has an elevated "Km" for polymer only for reactions with noncomplementary nucleotides. The wild type and L88 mutator enzymes also utilized both noncomplementary nucleotides much more frequently than the CB120 antimutator enzymes with poly [d(A-T)] as the template-primer. The T4 gene 32DNA unwinding protein appears to facilitate the correct reading of this template since it decreases the ratio of incorrect nucleotides utilized by both the wild type and L88 mutator polymerases.

Coliphages↗
PubMed1975

Control of chromosome replication in thymine-requiring strains of Bacillus subtilis 168.

Study of the replication pattern of a number of B. subtilis 168 strains under controlled physiological conditions revealed great interstrain variation in control of replication. Replication patterns were calculated from ratios of purA16/leu-8 and purA16/metB5 transformation frequency. The thymine-independent strains are under strict regulation with an average of one replication position per chromosome during log phase. After starvation for required amino acids or sporulation, the chromosome is in a completed state with no replication forks (class I). In contrast, several thymine-requiring strains (class III) have an average of three to four replication positions per chromosome during log phase (multiforked replication) of which one to two remain uncompleted after amino acid starvation or sporulation. The other thymine-requiring strains studied are intermediate (class II) in that they have an average of two replication positions per chromosome during log phase and one after amino acid starvation or sporulation. Pulse chase experiments indicate that the deoxyribonucleic acid which is close to the chromosomal origin on each branch of the multiforked chromosome is bound to a rapidly sedimenting cellular fraction, presumably membrane.

Bacillus subtilis↗
PubMed1972

8-Azaguanine resistance in mammalian cells. I. Hypoxanthine-guanine phosphoribosyltransferase.

Chinese hamster cells were treated with ethyl methanesulfonate or N-methyl-N'-nitro-N-nitrosoguanidine, and mutants resistant to 8-azaguanine were selected and characterized. Hypoxanthine-guanine phosphoribosyltransferase activity of sixteen mutants is extremely negative, making them suitable for reversion to HGPRTase(+). Ten of the extremely negative mutants revert at a frequency higher than 10(-7) suggesting their point mutational character. The remaining mutants have demonstrable HGPRTase activity and are not useful for reversion analysis. Five of these mutants have < 2% HGPRTase and are presumably also HGPRTase point mutants. The remaining 14 mutants utilize exogenous hypoxanthine for nucleic acid synthesis poorly, and possess 20-150% of wild-type HGPRTase activity in in vitro. Their mechanism of 8-azaguanine resistance is not yet defined.

Adenine↗
PubMed1972

Micrococcal nuclease treatment of bacteriophage heads alters the right-hand cohesive end of lambda deoxyribonucleic Acid.

Isolated bacteriophage lambda heads were exposed to micrococcal nuclease prior to addition of the phage tail. The deoxyribonucleic acid (DNA) was extracted from the heads and sheared to half-molecules whose cohesive ends were annealed to normal lambda DNA half-molecules. Melting curves of each of the cohered halves indicated that only the right-hand termini are altered by nuclease treatment.

Journal Article↗