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PubMed1980

[Effect of sensitization and delayed hypersensitivity reaction on tumor growth in mice].

Mice BALB/c during 8--10 weeks were sensitized by percutaneous injections of BCG vaccine or living B-243 staphylococci weekly, and after 10 days they were inoculated isogenic adenocarcinoma "Akatol". Compared with the control animals the tumor growth was found to be retarded. A more considerable retardation of the growth and in 50% the complete tumor regression was noted in sensitized mice, which repeatedly, since the day of inoculation, were injected subcutaneously or intratumorously alttuberculin or staphylococcic phagolysate, respectively. A gain of the tumor mass was associated with concomitant lessening of skin edema in response to test-allergen injection. Injections of alttuberculin in BCG-sensitized mice C3H/He contribute to an increased cytotoxicity of peritoneal macrophages against the cells of mammary gland isogenic tumor.

Adenocarcinoma↗
PubMed1980

Augmentation of glycogen synthesis under stringent control in Escherichia coli.

When Escherichia coli strain CP78 (rel+) was starved for isoleucine by the addition of valine, the amount of glucose in polymeric form in the cells increased markedly compared to that of the control cells. In contrast, this phenomenon was not seen in strain CP79 (rel-). The increase in CP78 was shown to be due to the increase of glycogen. These results indicate that glycogen synthesis was augmented under stringent control. This was confirmed using other isogenic pairs of rel+ and rel- strains starved for other amino acids. When the cultivation temperature of strains 10B601 (rel+) and 10B602 (rel-) possessing temperature-sensitive valyl-tRNA synthetase was shifted from 30 degrees C to 40 degrees C, no difference was observed in the response of glycogen synthesis between the two strains. These results indicate that protein synthesis was necessary for the augmentation of glycogen synthesis and that guanosine 5'-diphosphate 3'-diphosphate did not exert its effect through stimulation of the activity of pre-existing enzyme(s) involved in glycogen synthesis. These conclusions were supported by the results of experiments using chloramphenicol and rifampicin. The rates of glucose utilization of CP78 and CP79 were decreased to nearly the same extent by valine addition. This suggests that the regulation site of glycogen synthesis under stringent control resides in a step after the transport of glucose by the phosphotransferase system.

Arginine↗
PubMed1977

A cytokinetic analysis of bacillus calmette-guérin-induced growth control of a murine leukemia.

The cytokinetics of an isogeneic, transplantable, lymphoid leukemia, growing as an ascitic tumor in the C57BL/6 mouse, has been investigated during normal growth and during regression induced by weekly injections i.v. of 1.0 mg Bacillus Calmette-Guérin (BCG). Survival was significantly prolonged in the BCG-treated group, and 27% of the mice were apparently cured. The tumor growth curves showed, furthermore, that BCG-rreated mice could be divided into two groups according to whether the ascitic tumor cell number was at control level or below that of the controls. By methods such as stathmokinetics, tritiated thymidine autoradiography, and cytophotometry, it was demonstrated that the proliferative activity was higher in BCG mice with a low tumor mass as compared to controls and BCG mice with a tumor mass similar to that of controls. The cytokinetic characteristics of BCG mice with a low ascitic tumor cell number were especially expressed by high mitotic activity, high initial labeling indices, short potential tumor doubling time, and a low number of G0-G1 cells. Furthermore the ascitic tumor cell loss rate was increased in these mice during the whole experimental period. It was deduced from the various parameters and especially from the cytophotometric and autoradiographic results that BCG induces a preferential kill of tumor cells in G0-G1 and the first part of the S phase. In addition, the cytological aspects of the ascitic tumor were found to be related to the cell kinetic pattern as the amount of small and large tumor cells increased and decreased, respectively, with accumulation of tumor cells in G0-G1.

Animals↗
PubMed2002

Late G-CSF after allogeneic bone marrow or peripheral blood stem cell transplantation: a prospective controlled trial.

Granulocyte colony-stimulating factor (G-CSF) is widely used to accelerate neutrophil recovery after allogeneic BMT or PBSC transplantation. The optimal time to start G-CSF treatment is not known. Forty-two patients undergoing allogeneic BMT or PBSC transplantation for hematological malignancies received G-CSF either on day 6 or on day 9 post transplant. The time to hematological recovery was monitored and the two groups were compared with respect to peritransplant morbidity and mortality. Recovery of the neutrophil counts to >0.1 x 10(9)/l, > 0.5 x 10(9)/l and >1.0 x 10(9)/l were not significantly different in either group. There was no difference in recovery of red blood cell and platelet counts and no difference between the two groups with respect to the number of febrile days or number of days on antibiotic treatment. Documented bacterial, viral or fungal infections did not occur more often when G-CSF treatment was started on day 9. Delaying treatment with G-CSF resulted in a significant reduction in the length of treatment from 13 to 10 days (23.1% reduction). Reducing the length of the treatment by 3 days lowered the costs by 395.40 Euro per patient. Delaying G-CSF treatment and starting on day 9 after BMT or PBSC transplantation is safe and results in a clear economic benefit.

Adolescent↗
PubMed2006

Analysis of flavonoids in pubescence of soybean near-isogenic lines for pubescence color loci.

T and Td loci control pubescence color of soybean with epistatic effects (TT TdTd, tawny; TT tdtd, light tawny or near-gray; tt TdTd or tt tdtd, gray). The objective of this study was to investigate the nature of flavonoids in the pubescence of near-isogenic lines (NILs) for these loci. Flavonoids were extracted with methanol from pubescence of cultivar Clark with tawny pubescence (TT TdTd) and its NILs; from Clark-t with gray pubescence (tt TdTd) and Clark-td with near-gray pubescence (TT tdtd); and from a pair of NILs, To7B with tawny (TT TdTd) and To7G with gray pubescence (tt TdTd). Primary flavonoids were flavone aglycones. Luteolin and apigenin were predominant in NILs with tawny and gray pubescence, respectively. Small amount of 7-O-glucosides of the 2 flavones were also detected. Alleles at T locus were associated with 3'-hydroxylation in the B-ring of the flavones. The primary flavonoids in Clark-td were luteolin similar to Clark, but its amount was halved. High performance liquid chromatography peaks probably corresponding to isoflavonoids were found only in Clark-td in 2003. However, the peaks were not observed in 2005. The above results suggest that Td may encode a structural or a regulatory gene controlling flavone biosynthesis. Pigments remained visible in pubescence after methanol extraction, suggesting that a major part of the pigments was polymerized. Surface rinsing experiments revealed that flavone aglycones exist outside the surface of cells.

Alleles↗
PubMed1999

Influence of transgenic overexpression of phospholamban on postextrasystolic potentiation.

Twelve mice with PLB overexpression (PLBOE), and 11 isogenic FVB/N wild-type (WT) controls, were anesthetized and instrumented with a 1.4 F Millar catheter in the LV and a 1 F pacemaker in the right atrium. At a cycle length of 200 ms and a fixed extrastimulus of 120 ms, extrastimuli with increasing intervals (PESI) up to 1000 ms were introduced, and the peak rates of LV isovolumic contraction (+/- dP/dtmax) were normalized and fit to monoexponential equations. In a subset of animals, the protocols were repeated after ryanodine (4 ng/g) was given to deplete SR Ca2+ stores. The time constant and the plateau of the exponential curve fits were significantly greater in PLBOE than WT (107.8 +/- 7.0 v 75.2 +/- 5.5 ms and 1.39 +/- 0.03 v 1.08 +/- 0.02, both P < 0.05). At 200, 600 and 1000 ms, the normalized dP/dt was significantly greater in PLBOE than WT. After ryanodine, normalized dP/dt was significantly decreased in PLBOE, but unchanged in WT. The protein levels of the sodium-calcium exchanger normalized to calsequestrin were increased 3.7 +/- 0.3-fold in PLBOE compared to controls. In conclusion, the phospholamban level is a critical determinant of postextrasystolic potentiation in this transgenic model, and is differentially impaired by ryanodine at long diastolic intervals in PLBOE v controls. These differences may be due in part to changes in the protein level and resultant activity of the sodium calcium exchanger.

Adenosine Triphosphatases↗
PubMed2000

Growth-phase regulation of the Escherichia coli thioredoxin gene.

The two promoters of Escherichia coli trxA gene were separately cloned into pKO100 as well as pJEL170. Galactokinase expression in cells containing the pKO100 derivatives was found to be negatively correlated with growth rate and was 6- to 20-fold higher in stationary cultures than in exponential cultures. The expression of trxA-galK was induced by amino acid starvation in a RelA(+) strain but not in an isogenic Rel(-) strain indicating that the control involves guanosine 3',5'-bispyrophosphate (ppGpp). RpoS, which appears to be essential for expression of most stationary phase expressed genes, is not required for trxA expression. Increased expression of relA, which increases ppGpp concentration, increases trxA expression.

Amino Acids↗
PubMed2000

The influence of oxygen toxicity on yeast mother cell-specific aging.

The effect of deleting both catalase genes and of increased oxygen as well as paraquat (a pro-oxidant) on the replicative life span of yeast mother cells has been investigated to test the so-called oxygen theory of aging. This is well established in higher organisms, but has not been extensively tested in the unicellular yeast model system. Life span determinations were performed in ambient air or in a controlled atmosphere (55% oxygen) and an isogenic series of strains deleted for one or both yeast catalases was used and compared with wild type. In the absence of cellular catalase, increased oxygen caused a marked decrease in life span that could be completely reversed by adding 1 mM GSH, a physiological antioxidant, to the yeast growth medium. In a second unrelated strain, the effects were similar although even the wild type showed a decrease in life span when oxygen was increased. The effect could again be compensated by addition of extracellular GSH. Our results show that manipulating the detoxification of reactive oxygen species has a profound effect on yeast aging. These findings are discussed in the light of recent results relating to oxygen toxicity in the aging process of higher organisms.

Catalase↗
PubMed2003

Influence of anti-thymocyte globulin as part of the conditioning regimen on immune reconstitution following matched related bone marrow transplantation.

The aim of this work was to analyze the influence of anti-thymocyte globulin (ATG) as part of the conditioning regimen on immune reconstitution following matched related bone marrow transplantation. The rate and pattern of the recovery of total lymphocytes, natural killer (NK) cells, and several T and B cell subsets were determined in 38 patients for more than 2 years following BMT. We compared two patient groups: the first comprised 19 patients after matched related BMT without ATG prevention for graft-versus-host disease (GVHD) and the second contained 19 patients after matched related BMT with ATG treatment for GVHD prophylaxis. We observed impaired immune reconstitution in the ATG group in comparison with the non-ATG group, indicating a significant influence of ATG on immune recovery for several months after BMT.

Adolescent↗
PubMed2001

Inhibition of enteroaggregative Escherichia coli adhesion to HEp-2 cells by secretory immunoglobulin A from human colostrum.

BACKGROUND: Enteroaggregative Escherichia coli (EAEC) is an important agent of the persistent diarrhea among low socioeconomic level children in developing countries that may be associated with chronic undernourishment. Breast-feeding is effective in protecting infants against diarrhea and other infectious diseases. The aim of the study is to verify the ability of human colostrum to inhibit aggregative adhesion of EAEC to HEp-2 cells and the presence of antibodies reactive to antigenic fractions of EAEC in colostrum samples. METHODS: Enzyme-linked immunosorbent assay, immunoblotting and adhesion assays of EAEC to HEp-2 cells were done with pooled or individual colostrum samples (n = 35). Assays were performed with a well-known EAEC strain, 044:H18 E. coli (strain 042). Colostral IgA was isolated by affinity chromatography in Sepharose anti-human alpha chain column. RESULTS: Total colostrum and isolated IgA inhibited EAEC adhesion, and this ability was associated with the presence of IgA antibodies against a 15-kDa band, compatible with the subunits of aggregative adherence fimbrial adhesin II, characteristic of the 042 strain, absent in its plasmid-cured isogenic strain, that was used as control. Individual colostrum samples also inhibited adhesion, showed variable antibody titles against EAEC antigens in enzyme-linked immunosorbent assay and recognized many antigenic fractions in immunoblotting assays, including the 15-kDa band. CONCLUSIONS: These results confirm that IgA from human colostrum inhibits adhesion of EAEC to HEp-2 cells and suggest that colostrum IgA antibodies reactive to EAEC antigens may play a role in protection of infants against diarrhea caused by these bacteria.

Adult↗
PubMed1990

Gibberellic Acid Regulates Cell Wall Extensibility in Wheat (Triticum aestivum L.).

Mutations (Rht genes) blocking sensitivity to gibberellic acid (GA) were used to examine phytohormone mediated cell wall expansion in wheat (Triticum aestivum L.). Irreversible extensibility of immature leaf segments, as determined by stress/strain (instron) measurements, declined with Rht gene dose. Exogenous GA(3) significantly increased wall extensibility in the nonmutant controls but had no effect on the near-isogenic GA-insensitive genotypes. Furthermore, ancymidol, an inhibitor of gibberellin biosynthesis, diminished wall extensibility in the nonmutant control. Extensibility of immature segments was highly correlated with mature leaf sheath length (R = +0.95). The results indicate that wall yielding properties of expanding wheat leaves are associated with leaf cell expansion potential and that GA is involved in the determination of those properties.

Journal Article↗
PubMed2005

A role for the Plasmodium falciparum RESA protein in resistance against heat shock demonstrated using gene disruption.

During erythrocyte invasion, the Plasmodium falciparum Ring-infected erythrocyte surface antigen (RESA) establishes specific interactions with spectrin. Based on analysis of strains with a large chromosome 1 deletion, RESA has been assigned several functions, none of which is firmly established. Analysis of parasites with a disrupted resa1 gene and isogenic parental or resa3-disrupted controls confirmed the critical role of RESA in the surface reactivity of immune adult sera on glutaraldehyde-fixed ring stages. Absence of RESA did not influence merozoite invasion or erythrocyte membrane rigidity, was associated with a modest increase of cytoadhesion to CD36 under conditions of flow, but resulted in marked susceptibility to heat shock. resa1-KO-infected erythrocytes were prone to heat-induced vesiculation like uninfected erythrocytes, whereas parental or resa3-KO infected erythrocytes remained undamaged. Furthermore, a 6 h exposure of ring stages at 41 degrees C resulted in 33% culture inhibition of resa1-KO parasites while marginally impacting parental and resa3-KO parasite growth. This points to a role for RESA in protecting the infected erythrocyte cytoskeleton during febrile episodes. Infection patterns of resa1-KO and parental parasites in Saimiri sciureus indicated that RESA does not, at least on its own, modulate virulence in the squirrel monkey, as had been previously suggested.

Animals↗
PubMed2000

[Analysis of isogenic lines of the soft wheat carrying dominant alleles of Bg, Hg, and Rg1 genes using microsatellite and protein markers].

To determine tight linkage between morphological and molecular markers of the first homologous group of chromosomes of common wheat, microsatellite analysis of six near-isogenic lines with marker dominant alleles controlling back color (Bg; 1AS) and hairy glume (Hg; 1AS) and two lines bearing the dominant alleles of the gene for red glume color (Rgl; 1BS) was conducted. The component composition of gliadins in these lines was studied. Tight linkage of Bg, Hg, and Gli-A1 genes with a microsatellite marker Xgwm136 (1AS) and of Rg1 and Gli-B1 genes with markers Xgwm33 and Xgwm550 (1BS) was shown. Based on the results obtained and literature data, the most probable order of morphological and molecular markers on chromosomes of common wheat was determined. On chromosome 1AS, from the centromere to the telomere, the markers are located as follows: Xgwm136-Gli-A1-BgHg; on chromosome 1BS, in the same direction: Xgwm33-Gli-B1-Rg1-Xgwm550.

Chromosome Mapping↗
PubMed1999

[The diagnostic value of perforin and granzyme B genes mRNA expression in acute rejection after hamster to rat orthotopic liver transplantation].

OBJECTIVE: To explore the mRNA expression of perforin and granzyme B genes activated by cytotoxic T lymphocytes (CTL) for monitoring early acute rejection after liver transplantation. METHODS: The mRNA expression of perforin and granzyme B genes in grafts after gold hamster to rat liver transplantation was examined by reverse transcriptase polymerase chain reaction. Histological findings were studied comparatively, and isogenic rat liver transplantation was the control. RESULTS: The mRNA expression of perforin and granzyme B genes began to be up-regulated on the day 3 after transplantation, when no histologic evidence of rejection was found. Levels of expression significantly increased after day 4 and persisted through the whole course of rejection. In contrast, the control group showed no expression of mRNA for perforin and granzyme B. CONCLUSIONS: The determination of mRNA expression of perforin and granzyme B genes are useful to early diagnosis of acute rejection of liver transplantation.

Acute Disease↗
PubMed1989

The general control activator protein GCN4 is essential for a basal level of ARO3 gene expression in Saccharomyces cerevisiae.

The ARO3 gene encodes one of two 3-deoxy-D-arabino-heptulosonate-7-phosphate isoenzymes in Saccharomyces cerevisiae catalyzing the first step in the biosynthesis of aromatic amino acids. The ARO3-encoded 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase (EC 4.1.2.15) is feedback inhibited by phenylalanine; its isoenzyme, the ARO4 gene product, is inhibited by tyrosine. Both genes ARO3 and ARO4 are strongly regulated under the general control regulatory system. Cells carrying only one intact isogene are phenotypically indistinguishable from a wild-type strain when grown on minimal medium. The complete functional ARO3 promoter comprises 231 base pairs and contains only one TGACTA binding site for the general control activator protein GCN4. Mutating this element to TTACTA inhibits binding of GCN4 and results in a decreased basal level of ARO3 gene product and slow growth of a strain defective in its isogene ARO4. In addition, ARO3 gene expression cannot be elevated under amino acid starvation conditions. An ARO3 aro4 strain with gcn4 genetic background has the same phenotype of low ARO3 gene expression and slow growth. The amount of GCN4 protein present in repressed wild-type cells therefore seems to contribute to a basal level of ARO3 gene expression. The general control activator GCN4 has thus two functions: (i) to maintain a basal level of ARO3 transcription (basal control) in the presence of amino acids and (ii) to derepress the ARO3 gene to a higher transcription rate under amino acid starvation (general control).

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed1999

Immunogenicity of 2 serogroup B outer-membrane protein meningococcal vaccines: a randomized controlled trial in Chile.

CONTEXT: Meningococcal disease occurs worldwide, and serogroup B disease accounts for a large proportion of cases. Although persons younger than 4 years are at greatest risk for serogroup B meningococcal disease, vaccine efficacy has not been demonstrated in this age group. OBJECTIVE: To evaluate serum bactericidal activity (SBA) against homologous vaccine type strains and a heterologous Chilean epidemic strain of Neisseria meningitidis as a potential correlate for vaccine efficacy. DESIGN: Double-blind, randomized controlled trial conducted between March 14 and July 20, 1994. All blood samples were taken by December 1994. SETTING: Santiago, Chile, where a clonal serogroup B meningococcal disease epidemic began in 1993. PARTICIPANTS: Infants younger than 1 year (n = 187), children aged 2 to 4 years (n = 183), and adults aged 17 to 30 years (n = 173). INTERVENTION: Participants received 3 doses of outer-membrane protein (OMP) meningococcal vaccine developed in either Cuba or Norway or a control vaccine, with each dose given 2 months apart. Blood samples were obtained at baseline, prior to dose 3, and at 4 to 6 weeks after dose 3. MAIN OUTCOME MEASURE: Immune response, defined as a 4-fold or greater rise in SBA titer 4 to 6 weeks after dose 3 compared with prevaccination titer. RESULTS: Children and adult recipients of either meningococcal vaccine were more likely than controls to develop an immune response to the heterologous epidemic strain. After 3 doses of vaccine, 31% to 35% of children responded to the vaccine vs 5% to placebo; 37% to 60% of adults responded to vaccine vs 4% to placebo (P<.05 vs control for all). Infants, however, did not respond. In contrast, against homologous vaccine type strains, the response rate was 67% or higher among children and adults and 90% or higher among infants (P<.001 vs control for all). Subsequent SBA against 7 isogenic homologous target strains identified class 1 OMP as the immunodominant antigen. CONCLUSIONS: These data suggest that neither serogroup B OMP meningococcal vaccine would confer protection during a heterologous epidemic. However, epidemic strain-specific vaccines homologous for class 1 OMP are promising candidates for the control of epidemic serogroup B meningococcal disease.

Adolescent↗
PubMed1999

Role of Hpn and NixA of Helicobacter pylori in susceptibility and resistance to bismuth and other metal ions.

BACKGROUND: Helicobacter pylori produces Hpn, a 60-amino acid, histidine-rich protein that avidly binds nickel and zinc ions, and NixA, a high-affinity nickel transporter in the cytoplasmic membrane. We tested the hypothesis that Hpn and NixA govern susceptibility to metal ions in H. pylori. MATERIALS AND METHODS: Hpn-negative mutants of four H. pylori strains were constructed by standard allelic exchange techniques to yield isogenic Hpn+/Hpn-deficient pairs. A metal concentration that inhibited growth by 50% (IC50) was calculated for Ni2+, Zn2+, Cu2+, and Co2+ by comparing OD600 of cultures in metal-supplemented and control media. RESULTS: Among all four pairs of isogenic strains, the tolerance for Ni2+ was reduced significantly (p <.001) in the Hpn mutants; the mean IC50 value for wild-type strains was 1.9 mM; for the mutant, it was 0.8 mM. In contrast, growth inhibition by Zn2+ was identical within the fours pairs, as was Cu2+ and Co2+ tolerance in one pair tested. We also found that deletion of the hpn gene increases susceptibility to therapeutic forms of bismuth by testing a mutant and wild-type pair with ranitidine bismuth citrate, bismuth citrate, and four antibiotics. Minimal inhibitory concentrations of ranitidine bismuth citrate dropped from 9.2 to 2.3 microg/ml, and those of bismuth citrate dropped from 7.4 to 3.2 microg/ml (p <.05 for both comparisons), while susceptibility to the antibiotics was unaffected. Disruption of the nixA gene encoding the specific Ni2+ transport protein of H. pylori did not change susceptibility to bismuth. CONCLUSION: We concluded that bacteria lacking Hpn, cultured in vitro, are more susceptible than is the wild type to bismuth and Ni2+.

Bacterial Proteins↗