[Effect of aeration on the biosynthesis of levansucrase by Gluconobacter oxydans L-1].
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Fructans↗
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The effect of levan on the migration of different white blood cells across blood-vessel walls.
Nitrocellulose discs, untreated or immersed in paraffin oil or in Vespa orientalis venom, were inserted s.c. in mice. Similarly treated mice were given daily i.v. injections of levan. The discs were extracted, defibrinated, stained and the cells attached were counted. Paraffin oil and venom increased the number of monocytes on the discs. Treatment with levan reduced the number of polymorphs and giant cells, but increased the number of monocytes. Thus levan, which inhibits transendothelial migration of polymorphs, enhances the migration of monocytes.
Animals↗
Effect of high molecular levan on implantation and embryonic development in mice.
Pregnant Balb C mice were treated daily with levan beginning on either the first or the ninth day of pregnancy. Damage to embryos appeared on the eighth day in mice treated from the first day. In the second group, the damage was apparent two to four days after the levan treatment was begun. In both groups the damaged and dead embryos were found side by side with apparently normal conceptuses. The damage seems to have been caused by lesions to the trophoblast since it only occurred after implantation and placentation, and it appeared to be different from the antitumoral or the graft-rejection delaying effects of levan.
Animals↗
Blood levels of high-molecular levan in mice as a function of the route and duration of administration.
The influence of duration and of various routes of administration of native levan on blood levels of the drug was studied in mice. The blood levels varied with the doses administered. With a single i.p. injection of 20 mg levan/mouse the blood levels rose more rapidly than with higher and lower doses. In the second and third week of daily injections the rise and fall in blood levels became less pronounced. With treatment longer than 3 weeks spikes of maximal concentrations reappeared. After s.c. injections blood levels rose more slowly than after i.p. treatment. The findings indicate that: 1. high doses slow down absorption of levan; 2. after 7-21 days of treatment the RES (reticulo endothelial system) is more active in removal of levan from the blood stream than at the beginning of the treatment; 3. after treatment of 3 weeks and more the RES appears to be blocked and is again slow in the uptake of levan from the blood stream.
Animals↗
[Role of the nutrient medium components in regulating levansaccharase synthesis in Gluconobacter oxydans].
The effect of phosphate and acetate buffer systems on the growth of Gluconobacter oxydans and its synthesis of levansucrase was studied in nutrient media containing sorbitol. The intensification of constructive processes in media with an increased content of phosphate did not accelerate the enzyme biosynthesis by G. oxydans. As was shown in experiments with the intact cells of G. oxydans, the respiratory activity of the bacterium was stimulated in phosphate buffer supplemented with fructose. In contrast, acetate inhibited fructose oxidation and hindered the growth. At the same time, the synthesis of levansucrase increased. Such an increase was also found when the growth of G. oxydans was suppressed by sodium fluoride, an inhibitor of cellular metabolism. The extra synthesis of levansucrase useless during the growth on sorbitol should be attributed apparently to non-balanced growth of the bacterial culture caused by the suppression of respiration processes.
Acetates↗
[Levanase from Fusarium solani-68].
Extracellular levanase was isolated from the culture of Fusarium solani-68 by ammonium sulfate precipitation at 0.8 saturation and purified in part by Sephadex G-150 gel chromatography. Levanase showed maximum activity at pH = 6.0 and t = 45 degrees C. The levanase reaction (hydrolysis of high molecular levane with a molecular weight of 1--5 min) reached a maximum rate at a polysaccharide concentration of 6.7 mg/ml, Michaelis constant being 1.5 X 10(-6) M. Levanase remained stable at pH 5.4--7.5 and temperature 40--45 degrees C.
Bacterial Proteins↗
Serum expression of a VK structure, VK-11, associated with inulin antibodies controlled by gene(s) linked to the mouse IgCH complex.
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Animals↗
Plasma disappearance and distribution volume of polyfructosan in type 1 (insulin-dependent) diabetes mellitus.
The simultaneous plasma disappearance curves of the extracellular marker polyfructosan and 125I-fibrinogen were recorded for 3 h in 24 male long-term diabetic patients. Eight normal subjects served as a control group. The patients were divided into three groups according to their urinary albumin excretion: Group 1 had normal albumin excretion (< 30 mg/24 h), Group 2 had microalbuminuria (30-300 mg/24 h), and Group 3 had clinical nephropathy (> 300 mg/24 h). Using fibrinogen as a plasma volume reference, the permeability surface product (PdS), the plasma clearance rate at 10 min C1(10), and the extracellular volume (ECV) were determined from the polyfructosan curves. Plasma volume was similar in all groups, and no differences were found between Group 1 and the control group. PdS was higher in the albuminuric groups, but barely to reach significant levels (p = 0.08-0.03), while C1(10) was significantly elevated (p < 0.01). The ECV was also significantly higher in these patients (p = 0.02-0.005), resulting in a marked decrease of the plasma volume to extravascular volume ratio. The results suggest a general degeneration of perivascular resistance components in diabetic microvascular complications, followed by secondary alterations of fluid balance, due to decreasing colloid osmotic counterpressure and eventually increasing transcapillary hydrostatic pressure.
Albuminuria↗
[Renal clearance of hippurate in persons with chronic renal insufficiency].
In 8 subjects with chronic renal failure treated conservatively the renal hippurate clearance (CHip), polyfructosan (CPF) and creatinine (Ccr) clearance was assessed. The mean values of the investigated variables were as follows: CHip = 1.06 +/- 0.79 ml/s, CPF = 0.15 +/- 0.08 ml/s, Ccr = 0.27 +/- 0.17 ml/s. The ratios between the investigated clearance values were: CHip/CPF = 6.9 +/- 4.2 and CHip/Ccr = 4.2 +/- 1.4. The ratio of CHip/CPF was in some instances as high as 10 or more. Between values of CHip/CPF and the plasma hippurate concentration (PHip) a significant negative (non-linear correlation was found (p < 0.01). When the PHip values were very high, the value of the CHip/CPF ratio was close to 1. The recorded findings confirm that in subjects with chronic renal failure in the residual nephrons hippurate is synthetized and its urinary excretion in relation to glomerular filtration is increased. The findings suggest also that in these patients the tubular transport for hippurate is saturated. It will be necessary to take into account the possible saturation of tubular transport for hippurate when interpreting changes of drug excretion (i.e. those excreted by the same mechanism as hippurate) in subjects with chronic renal failure.
Adult↗
[Elimination of the thermostable exotoxin from B. thuringiensis after ingestion in the mouse].
When ingested by mice, the thermostable exotoxin is quickly eliminated in the "faeces", without fixation on the liver, the heart, the spleen or the kidneys. By quantitative study with a radio-active tritium-labelled exotoxin, this elimination is shown to be almost complete in 24 hours.
Adrenal Glands↗
Localized deletion-insertion mutations: a major factor in the evolution of immunoglobulin structural variability.
New and previously published amino acid sequences of mouse Vk chains completed to Trp35 were examined. This sequence includes a framework loop from NH2 to Cys23 and an antigen contacting complementarity region L1 which lies between Cys23 and Trp35. There are many different sequence variations from NH2 to Cys23 among BALB/c mouse Vk chains indicating multigenic control. Coordinately there is a remarkable structural heterogeneity of L1 size and sequence. Thus far chains with the same NH2-Cys23 sequence have similar sized L1, which suggests a close relationship between L1 size and characteristic NH2-Cys23 sequence. In this multigenic system selection for chains with size variations in L1 appears to have occurred. The mutational process that inserts or deletes triplets in this region is thought to be exploited in the derivation of new useful structural genes.
Amino Acid Sequence↗
[Decomposition of grass-fructosanes by lactobacilli from silage (author's transl)].
Lactobacilli isolated from grass silage were shown to belong to Lb. plantarum, Lb. casei and Lb. brevis. In studies on the degradation of fructosanes significant differences among the three species were found. While all strains of L. casei were able to degrade fructosanes from Dactylis glomerata or Phleum pratense regardless of the degree of polymerization, no nember of Lb. plantarum or Lb. brevis could attack these polysaccharides.
Animal Feed↗
Avidity maturation, repertoire shift, and strain differences in antibodies to bacterial levan, a type 2 thymus-independent polysaccharide antigen.
Our previous studies of 102 mAb from mice injected with bacterial levan (BL), a beta(2-->6) linked polyfructosan with beta(2-->1) branch points (inulin determinant, In) showed that BALB/c and CBA/Ca mAb differed in VH and VL gene family usage and fine specificity. We now show that BALB/c and CBA/Ca mAb used different VHJ606 germ-line genes in response to BL: V14A in BALB/c and a previously unidentified gene in CBA/Ca. CBA/Ca mice were found to lack the BALB/c V14A gene. Also, we have compared the responses to one (primary, 1 degree) or two (secondary, 2 degrees) injections of polysaccharide. The secondary BALB/c anti-BL panel has been expanded to a total of 22 mAb, and we report here the isotype, fine specificity, and VH/VL usage of the new mAb. Eight of nine primary BALB/c In-binding mAb were germ-line, whereas both secondary BALB/c In-binding mAb that were sequenced differed from the BALB/c germ-line gene V14A. Germ-line primary mAb were low avidity whereas all five secondary mAb and the one non-germ-line primary were high avidity. There was also a repertoire shift from approximately 90% VHJ606/V kappa 11 in primary mAb to only 50% in secondary mAb (p = 0.002). The data presented provide evidence that avidity maturation and repertoire shifts, features usually associated with a memory response to thymus-dependent Ags, also can occur in response to a second immunization with a thymus-independent type 2 polysaccharide Ag.
Amino Acid Sequence↗
Predicting glomerular function from adjusted serum creatinine in renal transplant patients.
In 22 individuals with a renal graft the correlations between the renal clearance of polyfructosan (CLPF), renal creatinine clearance (CLcr)--established under the same conditions as CLPF--and the value of glomerular function predicted using the equation by Cocroft and Gault (PredCLcr) were followed up, at an interval of 2-3 months, for 8-22 months. A significant linear correlation (r = 0.777, p < 0.001) was found between PredCLcr and CLPF as well as between PredCLcr and CLcr (r = 0.801, p < 0.001). Equally significant correlations, however, were established when relating the serum concentrations of creatinine (Scr) to 1/CLPF (r = 0.784, p < 0.001) and Scr to 1/CLcr (r = 0.744, p < 0.001). The values of the PredCLcr/CLPF and PredCLcr/CLcr ratios during follow-up in one and the same individual may vary significantly. This fluctuation exceeds maximal error of the analytical methods employed in one third of the individuals examined. When considering stabilization or slow changes in graft function on the basis of PredCLcr and CLPF we found significant discrepancies in more than one half of the individuals examined (64%). The findings support the assumption that more accurate methods must be used to assess graft glomerular function on long-term follow-up.
Adult↗
[Relation between creatinine clearance and glomerular filtration in long-term monitoring of individuals with kidney transplants].
The authors examined in 22 subjects with a transplanted kidney after 2- to 3-month intervals for a period of 8-22 months the renal creatinine clearance (Ccr) and glomerular filtration rate (GFR) based on polyfructosan clearance (CPF). The mean value of the Ccr was 72.9 (+/- 23.3) ml/min/1.73 m/ and CPF 52.0 (+/- 19.5) ml/min/1.73 m2. The mean value of the Ccr/CPF ratio was 1.45 (+/- 0.33) and the tubular creatinine secretion (Tcr) 4.8 (+/- 5.5) mumol/min/100 ml CPF. Between values of Ccr and CPF a significant correlation was found (r = 0.752, p < 0.001). The value of the Ccr/CPF ratio in the same individual varied markedly in the course of the follow up period. The differences between the maximal and minimal values of the ratio in the same subject were in 36% of the patients greater than could be explained by errors of the applied analytical methods. From comparison of values of creatinine clearance and polyfructosan clearance at the onset and at the end of the investigation period ensues than in one half of the investigated cases a discrepancy was found between changes of the investigated clearance values. The assembled findings are consistent with the ideal that tubular creatinine secretion in the transplanted kidney may vary considerably in the course of time. Due to significant changes of tubular creatinine secretion in the same subject discrepancies develop between changes of creatinine clearance and the GFR. When evaluating the long-term stabilization or small changes of GFR of the transplanted kidney only on the basis of creatinine clearance erroneous conclusions may be reached.
Adult↗
Idiotypic specificities and cross-reactivities of rabbit antibodies to human antidextran.
Idiotypic antibodies were prepared by immunizing two groups of rabbits with dextran-antidextran specific precipitates and purified antidextran obtained subsequently from the same human donor. Half of the animals were made tolerant to pooled human IgG. Tests showed that sera from tolerant rabbits reacted better with the antidextran preparation used to immunize the other group of animals than with the antidextran that formed part of their immunogen. Non-tolerant animals did not recognize this serological difference. Sera from animals immunized with the antidextran preparation donated later reacted better with this material irrespective of their tolerance to human IgG.
Animals↗
Purification and characterization of a novel levanoctaose-producing levanase from Pseudomonas strain K-52.
Levan-assimilating micro-organisms from soil samples were screened for levanoligosaccharide-generating enzyme production. The isolated strain K-52 produced an extracellular levanoctaose-generating enzyme and was identified as belonging to genus Pseudomonas. The levanase was purified to homogeneity by (NH4)2SO4 fractionation and successive column chromatography on DEAE-cellulose, phenyl-Toyopearl 650 M, Sephadex G-100 and hydroxyapatite. The molecular mass of the enzyme was estimated as approx. 38 kDa by both SDS/PAGE and gel filtration, and its isoelectric point was approx. pH 4.8. The optimum temperature and pH for the enzyme reaction were 35 and 7.0 respectively. The enzyme was stable at a pH range of 6.0-9.0 at 4 degrees C and up to 40 degrees C at pH 6.8. The enzyme activity was inhibited by Fe2+, Cu2+, Hg2+ and Ag2+. The levanase was specific toward 2,6-beta-D-fructosidic linkages of levan and did not hydrolyse other polysaccharides such as inulin and dextran. Chemical modification on the levanase suggested that cysteine and histidine residues are essential for enzyme activity. The levanoctaose liberated by levanase reaction was used selectively only by the intestinal beneficial micro-organisms, such as Bifidobacterium and Lactobacillus spp.
Bacterial Proteins↗