Microbacterium memoriense sp. nov., a member of the Actinomycetota from marine beach sediment of the north coast of Portugal

The oceans harbour a myriad of unknown micro-organisms that remain unstudied because of a failure to establish the right growth conditions under laboratory conditions. To overcome this limitation, an isolation effort inspired by the iChip was performed using marine sediments from Memória beach, Portugal. A novel strain, PMIC_1C1BT, was obtained and subjected to a polyphasic study. Cells of strain PMIC_1C1BT were Gram-positive, rod-shaped, divided by binary fission and formed colonies that were shiny light-yellow. Based on its full 16S rRNA gene sequence, strain PMIC_1C1BT was phylogenetically associated to the genus Microbacterium and its closest relatives were Microbacterium aurum KACC 15219T (98.55 %), Microbacterium diaminobutyricum RZ63T (98.48 %) and Microbacterium hatanonis JCM 14558T (98.13 %). Strain PMIC_1C1BT had a genome size of 2 761 607 bp with 67.71 mol% of G+C content and 2582 coding sequences, which is lower than the genus average. Strain PMIC_1C1BT grew from 15 to 30 °C, optimally at 25 °C, at pH 6.0 to 11.0, optimally between pH 6.0 and 8.0, and from 0 to 5 % (w/v) NaCl, optimally between 2.0 and 3.0 %. It grew with casamino acids, glutamine, methionine, N-acetylglucosamine, sodium nitrate, tryptophan, urea and valine as sole nitrogen sources, and arabinose and cellobiose as sole carbon sources. The major cellular fatty acids were anteiso-C15 : 0, iso-C16 : 0 and iso-C17 : 0. Genome mining revealed the presence of four biosynthetic gene clusters (BGCs) with low similarities to other known BCGs. Based on the polyphasic data, strain PMIC_1C1BT is proposed to represent a novel species, for which the name Microbacterium memoriense sp. nov. (=CECT 30366T=LMG 32350T) is proposed.

Potential of acetic acid to restore methane production in anaerobic reactors critically intoxicated by ammonia as evidenced by metabolic and microbial monitoring

BACKGROUND

Biogas and biomethane production from the on-farm anaerobic digestion (AD) of animal manure and agri-food wastes could play a key role in transforming Europe's energy system by mitigating its dependence on fossil fuels and tackling the climate crisis. Although ammonia is essential for microbial growth, it inhibits the AD process if present in high concentrations, especially under its free form, thus leading to economic losses. In this study, which includes both metabolic and microbial monitoring, we tested a strategy to restore substrate conversion to methane in AD reactors facing critical free ammonia intoxication.

RESULTS

The AD process of three mesophilic semi-continuous 100L reactors critically intoxicated by free ammonia (> 3.5 g_N L-1; inhibited hydrolysis and heterotrophic acetogenesis; interrupted methanogenesis) was restored by applying a strategy that included reducing pH using acetic acid, washing out total ammonia with water, re-inoculation with active microbial flora and progressively re-introducing sugar beet pulp as a feed substrate. After 5 weeks, two reactors restarted to hydrolyse the pulp and produced CH4 from the methylotrophic methanogenesis pathway. The acetoclastic pathway remained inhibited due to the transient dominance of a strictly methylotrophic methanogen (Candidatus Methanoplasma genus) to the detriment of Methanosarcina. Concomitantly, the third reactor, in which Methanosarcina remained dominant, produced CH4 from the acetoclastic pathway but faced hydrolysis inhibition. After 11 weeks, the hydrolysis, the acetoclastic pathway and possibly the hydrogenotrophic pathway were functional in all reactors. The methylotrophic pathway was no longer favoured. Although syntrophic propionate oxidation remained suboptimal, the final pulp to CH4 conversion ratio (0.41 ± 0.10 LN_CH4 g_VS-1) was analogous to the pulp biochemical methane potential (0.38 ± 0.03 LN_CH4 g_VS-1).

CONCLUSIONS

Despite an extreme free ammonia intoxication, the proposed process recovery strategy allowed CH4 production to be restored in three intoxicated reactors within 8 weeks, a period during which re-inoculation appeared to be crucial to sustain the process. Introducing acetic acid allowed substantial CH4 production during the recovery period. Furthermore, the initial pH reduction promoted ammonium capture in the slurry, which could allow the field application of the effluents produced by full-scale digesters recovering from ammonia intoxication.

Stieleria tagensis sp. nov., a novel member of the phylum Planctomycetota isolated from Tagus River in Portugal

A bacterial strain was isolated from a brackish water sample of Tagus river, Alcochete, Portugal and was designated TO1_6T. It forms light pink colonies on M13 medium supplemented with N-acetylglucosamine. Cells are pear-shaped to spherical, form rosettes and divide by budding. Strain TO1_6T presents a mesophilic and neutrophilic profile, with optimum growth at 20 to 25 °C and pH 7.0 to 7.5, and vitamin supplementation is not required to promote its growth. The genome of the novel isolate is 7.77 Mbp in size and has a DNA G + C content of 56.3%. Based on its 16S rRNA gene sequence, this strain is affiliated with the phylum Planctomycetota. Further taxonomic characterization using additional phylogenetic markers, namely rpoB gene sequence (encoding the β-subunit of the DNA-dependent RNA polymerase), as well as Percentage of conserved proteins, average nucleotide identity and average amino acid identity, suggest the affiliation of strain TO1_6T to the genus Stieleria, a recently described taxon in the family Pirellulaceae, order Pirellulales and class Planctomycetia. Based on the genotypic, phylogenetic and physiological characterization, we here describe a new species represented by the type strain TO1_6T (= CECT 30432T, = LMG 32465T), for which the name Stieleria tagensis sp. nov. is proposed.

Streptomyces meridianus sp. nov. isolated from brackish water of the Tagus estuary in Alcochete, Portugal

An isolation effort focused on sporogenous Actinomycetota from the Tagus estuary in Alcochete, Portugal, yielded a novel actinomycetal strain, designated MTZ3.1T, which was subjected to a polyphasic taxonomic study. MTZ3.1T is characterised by morphology typical of members of the genus Streptomyces, with light beige coloured substrate mycelium, which does not release pigments to the culture medium and with helicoidal aerial hyphae that differentiate into spores with a light-grey colour. The phylogeny of MTZ3.1T, based on the full 16S rRNA gene sequence, indicated that its closest relatives were Streptomyces alkaliterrae OF1T (98.48 %), Streptomyces chumphonensis KK1-2T (98.41 %), Streptomyces albofaciens JCM 4342T (98.34 %), Streoptomyces paromomycinus NBRC 15454T (98.34 %) and Streptomyces chrestomyceticus NRBC 13444T (98.34 %). Moreover, average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridisation (dDDH) are below the species cutoff values (ANI 67.70 and 68.35 %, AAI 77.06 and 76.71 % and dDDH 22.10 and 21.50 % for S. alkaliterrae OF1T and S. chumphonensis KK1-2T, respectively). Whole genome sequencing revealed that MTZ3.1T has a genome of 5 644 485 bp with a DNA G+C content of 71.29 mol% and 5044 coding sequences. Physiologically, MTZ3.1T is strictly aerobic, able to grow at 15-37 °C, optimally at 25 °C and between pH5 and 8 and showed high salinity tolerance, growing with 0-10 %(w/v) NaCl. Major cellular fatty acids are C15 : 0, iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. Furthermore, it was able to utilise a variety of nitrogen and carbon sources. Antimicrobial screening indicated that MTZ3.1T has potent anti-Staphylococcus aureus activity. On the basis of the polyphasic data, MTZ3.1T is proposed to represent a novel species, Streptomyces meridianus sp. nov. (= CECT 30416T = DSM 114037T=LMG 32463T).

A holobiont approach towards polysaccharide degradation by the highly compartmentalised gut system of the soil-feeding higher termite Labiotermes labralis

BACKGROUND

Termites are among the most successful insects on Earth and can feed on a broad range of organic matter at various stages of decomposition. The termite gut system is often referred to as a micro-reactor and is a complex structure consisting of several components. It includes the host, its gut microbiome and fungal gardens, in the case of fungi-growing higher termites. The digestive tract of soil-feeding higher termites is characterised by radial and axial gradients of physicochemical parameters (e.g. pH, O₂ and H₂ partial pressure), and also differs in the density and structure of residing microbial communities. Although soil-feeding termites account for 60% of the known termite species, their biomass degradation strategies are far less known compared to their wood-feeding counterparts.

RESULTS

In this work, we applied an integrative multi-omics approach for the first time at the holobiont level to study the highly compartmentalised gut system of the soil-feeding higher termite Labiotermes labralis. We relied on 16S rRNA gene community profiling, metagenomics and (meta)transcriptomics to uncover the distribution of functional roles, in particular those related to carbohydrate hydrolysis, across different gut compartments and among the members of the bacterial community and the host itself. We showed that the Labiotermes gut was dominated by members of the Firmicutes phylum, whose abundance gradually decreased towards the posterior segments of the hindgut, in favour of Bacteroidetes, Proteobacteria and Verrucomicrobia. Contrary to expectations, we observed that L. labralis gut microbes expressed a high diversity of carbohydrate active enzymes involved in cellulose and hemicelluloses degradation, making the soil-feeding termite gut a unique reservoir of lignocellulolytic enzymes with considerable biotechnological potential. We also evidenced that the host cellulases have different phylogenetic origins and structures, which is possibly translated into their different specificities towards cellulose. From an ecological perspective, we could speculate that the capacity to feed on distinct polymorphs of cellulose retained in soil might have enabled this termite species to widely colonise the different habitats of the Amazon basin.

CONCLUSIONS

Our study provides interesting insights into the distribution of the hydrolytic potential of the highly compartmentalised higher termite gut. The large number of expressed enzymes targeting the different lignocellulose components make the Labiotermes worker gut a relevant lignocellulose-valorising model to mimic by biomass conversion industries.

Stieleria sedimenti sp. nov., a Novel Member of the Family Pirellulaceae with Antimicrobial Activity Isolated in Portugal from Brackish Sediments

The phylum Planctomycetota is known for having uncommon biological features. Recently, biotechnological applications of its members have started to be explored, namely in the genus Stieleria. Here, we formally describe a novel Stieleriaisolate designated as strain ICT_E10.1T, obtained from sediments collected in the Tagus estuary (Portugal). Strain ICT_E10.1T is pink-pigmented, spherical to ovoid in shape, and 1.7 µm ± 0.3 × 1.4 µm ± 0.3 in size. Cells cluster strongly in aggregates or small chains, divide by budding, and have prominent fimbriae. Strain ICT_E10.1T is heterotrophic and aerobic. Growth occurs from 20 to 30 °C, from 0.5 to 3% (w/v) NaCl, and from pH 6.5 to 11.0. The analysis of the 16S rRNA gene sequence placed strain ICT_E10.1T into the genus Stieleria with Stieleria neptunia Enr13T as the closest validly described relative. The genome size is 9,813,311 bp and the DNA G+C content is 58.8 mol%. Morphological, physiological, and genomic analyses support the separation of this strain into a novel species, for which we propose the name Stieleria sedimenti represented by strain ICT_E10.1T as the type of strain (=CECT 30514T= DSM 113784T). Furthermore, this isolate showed biotechnological potential by displaying relevant biosynthetic gene clusters and potent activity against Staphylococcus aureus.

Rhodopirellula aestuarii sp. nov., a novel member of the genus Rhodopirellula isolated from brackish sediments collected in the Tagus River estuary, Portugal

Bacteria within the phylum Planctomycetota are biologically relevant due to unique characteristics among prokaryotes. Members of the genus Rhodopirellula can be abundant in marine habitats, however, only six species are currently validly described. In this study, we expand the explored genus diversity by formally describing a novel species. The pink-coloured strain ICT_H3.1^T was isolated from brackish sediments collected in the Tagus estuary (Portugal) and a 16S rRNA gene sequence-based analysis placed this strain into the genus Rhodopirellula (family Pirellulaceae). The closest type strain is Rhodopirellula rubra LF2^T, suggested by a similarity of 98.4% of the 16S rRNA gene sequence. Strain ICT_H3.1^T is heterotrophic, aerobic and able to grow under microaerobic conditions. The strain grows between 15 and 37 °C, over a range of pH 6.5 to 11.0 and from 1 to 8% (w/v) NaCl. Several nitrogen and carbon sources were utilized by the novel isolate. Cells have an elongated pear-shape with 2.0 ± 0.3 × 0.9 ± 0.2 µm in size. Cells of strain ICT_H3.1^T cluster in rosettes through a holdfast structure and divide by budding. Younger cells are motile. Ultrathin cell sections show cytoplasmic membrane invaginations and polar fimbriae. The genome size is 9,072,081 base pairs with a DNA G + C content of 56.1 mol%. Genomic, physiological and morphological comparison of strain ICT_H3.1^T with its relatives suggest that it belongs to a novel species within the genus Rhodopirellula. Hence, we propose the name Rhodopirellula aestuarii sp. nov., represented by ICT_H3.1^T (=CECT30431^T = LMG32464^T) as the type strain of this novel species. 16S rRNA gene accession number: GenBank = OK001858. Genome accession number: The Whole Genome Shotgun project has been deposited at DDBJ/ENA/GenBank under the accession JAMQBK000000000. The version described in this paper is version JAMQBK010000000.

Relationship between body composition, sex hormones and leptinemia in hemodialyzed patients with chronic renal failure

BACKGROUND

Females are characterized by significantly higher plasma leptin concentration than males. It seems likely that sex hormones influence leptinemia independently from differences in body composition. The aim of the present study was to analyze the contribution of plasma concentrations of testosterone and estradiol on leptinemia in hemodialyzed patients.

METHODS

110 hemodialyzed patients--HD (60 M, 50 F) and 70 healthy subjects (HS) (30 M, 40 F) were enrolled in this study. Plasma leptin, testosterone or estradiol and CRP concentrations and body composition by dual-energy X-ray absorptiometry (DEXA) were assessed.

RESULTS

Total body fat was significantly higher in females than in males (27.5 +/- 1.5% vs. 17.2 +/- 1.0% of body weight in HD and 36.0 +/- 1.0% vs. 18.2 +/- 1.4% in HS, respectively). Plasma leptin concentrations were markedly higher in females than in males both in HD (27.9 +/- 5.4 ng/ml vs. 9.6 +/- 1.9 ng/ml) and HS (16.5 +/- 1.7 ng/ml vs.3.1 +/- 0.4 ng/ml). A highly significant, strong positive correlation was found between total fat mass (TFM) and leptinemia in all studied groups. No significant univaried correlation between plasma leptin and testosterone or estradiol concentrations respectively was found both in HD and HS. Multiple regression analyses showed that the main determinant of leptinemia is TFM (beta = 0.623 and 0.798 in HS females and males respectively, and beta = 1.058 and 0.797 in HD females and males respectively). Plasma concentration of testosterone (beta = -0.139 and beta = -0.075 in male HD and HS respectively) and estradiol (beta = 0.199 and beta = 0.046 in females HD and HS, respectively) contributed to leptinemia only in a minor degree.

CONCLUSION

Both testosterone and estradiol are minor contributors to leptinemia both in HS and HD patients. The main determinant of leptinemia in these subjects is total body fat mass.

Carvedilol does not modulate moderate exercise-induced hyperkalemia in hemodialysis patients

BACKGROUND AND AIM

Non-selective beta-adrenergic blockers may cause hyperkalemia in patients with end-stage renal failure. In contrast, alpha-adrenergic blockade has been found to decrease the hyperkalemic effect of physical exercise in healthy subjects, although we were unable to confirm this effect in hemodialysis patients. In a crossover design, we studied the effect of carvedilol, a non-selective beta-adrenergic blocker with an additional alpha1-blocking activity, on exercise-induced hyperkalemia in 17 anuric hemodialysis patients.

METHODS

All subjects were given either carvedilol (25 mg/day) or placebo for 2 weeks in a random order with a 2-week wash-out period. At the end of each treatment period they underwent a 30-minute exercise test on a bicycle ergometer with a fixed load of 20 W.

RESULTS

The treatment with carvedilol caused a significant decrease in blood pressure. Serum potassium before exercise tests was similar (5.37 +/- 0.2 and 5.24 +/- 0.2 mmol/l on carvedilol and placebo, respectively; mean +/- SE). During the exercise, serum potassium increased significantly (p < 0.001 in both tests) and subsequently decreased during 30 minutes of recovery (p < 0.05). The mean rate of potassium increment during the exercise was similar (23.3 +/- 3.3 micromol/l/min on carvedilol and 20.0 +/- 3.6 micromol/l/min on placebo). During recovery, the mean rate of potassium decrement was 5.0 +/- 3.0 micromol/l/min and 6.7 +/- 2.7 micromol/l/min, respectively. Serum sodium, ionized calcium, insulin and plasma renin activity were similar before the exercise tests and did not change during the exercise.

CONCLUSION

Carvedilol does not enhance the hyperkalemic effect of moderate physical exercise in anuric hemodialysis patients.

[Chronic allograft nephropathy]

In spite of improved one year renal allograft survival long-term results of renal transplantation did not change since several years. Progressive decline of graft function developing few years after renal transplantation remains a significant problem in renal replacement therapy. The clinical manifestation of progressive impairment of the kidney transplant is heterogeneous and the differential diagnosis of chronic graft rejection is difficult, even if histopathological examination is performed. Improvement of immunosuppressive therapy and avoidance of nonimmunologic factors which increase the risk of graft failure seem to influence markedly function of kidney grafts.

Atrial natriuretic peptide and arginine-vasopressin secretion in patients with active renal stone disease

The pathogenesis of active renal stone disease (ARSD) is still not fully elucidated. In the present study the role of atrial natriuretic peptide (ANP) and arginine-vasopressin (AVP) as potential pathogenetic factors in ARSD were examined. Thirty patients with ARSD and 21 healthy subjects (HS) were examined both under bed rest (BR) and head-out water immersion (WI) conditions. Serum concentrations of electrolytes (Na, Ca, Mg), ANP and AVP were assessed before (0'), and after 60 and 120 minutes of BR or WI, respectively. Urinary excretions of Na, Ca, Mg, and oxalates were also estimated during BR and WI. Patients with ARSD showed higher basal plasma levels of ANP and a greater response of ANP secretion, but a lower suppression of plasma AVP to WI induced hypervolaemia as compared with the controls. In addition, in patients with ARSD the physiological relationship between plasma AVP concentration and urinary excretion of Ca and Mg (positive correlation), between plasma ANP level and urinary excretion of Ca and Mg (negative correlation), and between plasma ANP and AVP concentration (negative correlation), respectively, were absent. In addition, patients with ARSD showed a positive correlation between plasma ANP and urinary oxalate excretion. From the results obtained in this study we conclude that both AVP and ANP may be involved in the pathogenesis of ARSD.

[Secretion of atrial natriuretic peptide in patients with active renal stone disease]

The role of the atrial natriuretic peptide (ANP) in Na and water metabolism is well recognized. Much less known is the physiological importance of ANP in the metabolism of other electrolytes e.g. calcium and magnesium, which are presumably involved in the pathogenesis of active renal stone disease (ARSD). The present study aimed to assess the potential role of ANP in the pathogenesis of ARSD. Two groups of subjects were examined. The first one comprised 30 patients with ARSD (diagnosed according to Smith's criteria) while the second one consisted of 21 healthy subjects. Both groups were studied under bed rest (BR) and water immersion (IW) conditions. The examined groups were not different by age, sex, serum electrolyte profile (Na, Ca, Mg) and urinary excretion of Na, Ca, Mg and oxalic acid. Patients with ARSD showed significantly higher basal level of ANP and a significantly higher response of ANP secretion to IW as normals. In spite of this abnormality, patients with ARSD showed a similar increase in water, Na, Ca, Mg and oxalic acid excretion stimulated by IW as compared with normals. In contrast to healthy subjects, patients with ARSD showed no significant correlation between serum ANP levels and urinary excretion of Na, Ca and Mg. In addition, only patients with ARSD showed a significant positive correlation between serum ANP and urinary excretion of oxalic acid during WI. Results obtained in this study suggest, that ANP may be involved in the pathogenesis of ARSD.

[Relationship between renal biopsy histopathology and profile of changes in serum protein, lipids and proteinuria in patients with nephrotic syndrome due to chronic glomerulonephritis]

Relationship was assessed between the type of renal pathology and the degree of plasma protein and lipid abnormalities in 59 patients with nephrotic syndrome due to chronic glomerulonephritis (GN). All patients were divided into 5 subgroups according to the type of renal pathology (extracapillary proliferative GN--23, mesangioproliferative GN--18, membranous GN--5, minimal changes--5, other--8 patients) and according to the presence (22 patients) or absence (37 patients) of altered interstitium (inflammation and/or fibrosis). In all patients the following parameters were analyzed: plasma levels of creatinine, total cholesterol and lipids, triglycerides, total protein, electrophoretic fractions of plasma proteins and urinary protein excretion. Type of renal pathology as well as presence of interstitial lesion did not influence the degree of protein and lipid abnormalities in nephrotic patients. Significantly more marked (p < 0.05) abnormalities in the serum and lipid profile were found in patients in whom 76-100% of all glomeruli were abnormal than in patients with a lower percentage of damaged glomeruli.

CONCLUSION

Percentage of damaged glomeruli but not the type of renal pathology (glomerular or/and interstitial) are the main factors influencing the magnitude of abnormal serum protein and lipid profiles in nephrotic patients.

KrF laser-pumped dye-laser studies

Dye-laser efficiency measurements were performed on four Coumarin dyes: C-485, C-498, C-500, and C-503, all operating near 500 nm. They were pumped with a 16-ns pulse-length KrF laser. The most efficient of the Coumarin dyes tested was C-498. The intrinsic efficiency of this dye was found to increase with pump rate. At a pump rate of 2 MW/cm(2), an intrinsic efficiency of > 20% was measured. Longer KrF laser pulses (> 1.2 µs) were also used to pump C-498 and resulted in comparable laser efficiencies at similar pump rates. The temporal relationship between the input KrF laser pump pulse and the output dye-laser pulse was studied and was found to differ significantly for long and short pulses. Significant improvement in long-pulse laser performance was observed when the laser-cavity configuration incorporated a skip mode.

[Analysing cause of death in chronically hemodialyzed patients]

The documentation was analysed of 123 haemodialysed patients dying in the years 1984-1990 in nine extracorporeal dialysis centres in the Provinces of Bielsko, Czestochowa and Katowice. Among the dying haemodialysed patients were 61 men and 62 women. The mean age of these patients was 43.7 +/- 1.0 years. The mean time from starting the haemodialysis therapy to death was 29.2 +/- 3.9 months. Mortality among the haemodialysed patients in individual years ranged from 6.5 to 14.4% and was 9.7% on the average. The most frequent death causes in this group of patient in the studied time period were infections (45.5%) and cardiovascular complications (35%). The results of the analysis of death causes in haemodialysed patients suggest the need of constant monitoring of the risk factors contributing to the development of infections and cardiovascular complications.

[Is it possible to transplant kidneys from donors whose death was caused by ethylene glycol intoxication?]

This paper describes 4 patients with a kidney graft from ethylene glycol intoxicated cadaver donors. Our results suggest usefulness of such donors for transplantation.

[Treatment of anemia with erythropoietin (rhuEPO) in patients with chronic kidney failure who are not yet in need of dialysis therapy]

Eleven uraemic predialysis patients have been selected for the treatment of anaemia with rhuEPO. Administration of rhuEPO was followed by a significant increase of the Hct value and haemoglobin concentration as well as an improvement of well being. The main adverse effects of rhuEPO therapy were the following: increase of blood pressure, reduction of the residual renal function and increase of serum potassium and phosphorous concentration. Monitoring of the iron status in uraemic predialysis patients on rhuEPO therapy seems to be mandatory.

Observation of parametric gain suppression in rotational Raman transitions of N(2) and H(2)

The ratio of forward Raman conversion thresholds for linearly and circularly polarized laser light has been measured in low-Fresnel-number configurations for the strongest rotational Raman transitions of N(2) and H(2). In both cases the ratio is found to be in the range 2.5-3, corresponding to a threshold-suppression factor of 1.7-2 for the linearly polarized laser light. The observed spatial distributions of the Stokes light also confirm the presence of suppression along the direction of propagation of the incident linearly polarized laser light. Numerical calculations are in good agreement with the experimental results.

Measurement of Raman gain of the S(8) transition of N(2)

The ratio of the rotational Raman gain coefficients g of N(2) [S(8), 0.91 amagat] and H(2) [S(1), 0.73 amagat] was determined at 295 K by measuring the 5% conversion threshold for each in the same focused configuration, using a circularly polarized 1054-nm laser. After correcting for dispersion, the optical Stark effect, transient effects, laser-wing Stokes seed injection, and mode-beat intensity modulation, we obtained g(N(2))/g(H(2)) = (8.0 +/- 1.2) x 10(-3), so that g(N(2)) = 4.0 +/- 0.8 cm/TW.

Effect of toluidines on drug metabolizing enzymes in rat liver, kidney and lung

The effect of pretreatment with o-, m- and p-toluidine on the drug-metabolizing enzymes of liver, kidney and lung in rats were investigated. The activities of microsomal aryl hydrocarbon hydroxylase (AHH), aminopyrine demethylase, NADPH-cytochrome c reductase, epoxide hydrolase, cytosolic glutathione S-transferase as well as the concentrations of cytochrome P-450 and cytochrome b5 were determined. The obtained results showed that o-toluidine increased the activity of AHH in all tested organs; a particularly marked increase was observed in the kidney. The activity of NADPH-cytochrome c reductase and the content of cytochrome b5 were enhanced by o-toluidine only in the liver. m-Toluidine enhanced the glutathione S-transferase activity while the p-isomer increased both the epoxide hydrolase and the glutathione S-transferase activities. p-Toluidine decreased the AHH and aminopyrine demethylase activities and the cytochrome P-450 content. These results may explain in part the previously reported observations on carcinogenic activity of o-toluidine.

The effect of sesquiterpene lactones, eupatoriopicrin and hydroxyisonobilin, on the glycolytic metabolism of human lymphocytes

The effect of two sesquiterpene lactones of the germacranolide group, eupatoriopicrin and hydroxyisonobilin, on the glycolytic metabolism of human lymphocytes stimulated by phytohemagglutinin was tested. Glucose and lactic acid levels as well as the activities of phosphofructokinase, glyceraldehyde 3-phosphate dehydrogenase, pyruvate kinase, and lactate dehydrogenase were measured. Both lactones caused a decrease in glucose consumption and lactic acid formation as well as the inhibition of the tested enzymes. A stronger inhibitory effect was observed in the case of hydroxyisonobilin, particularly with regard to phosphofructokinase and glyceraldehyde 3-phosphate dehydrogenase.

[Effect of anticoagulants on lymphocyte isolation by density gradient centrifugation]

The authors compared the efficiency of isolation and the purity of lymphocytes obtained by the method of centrifugation in a gradient of ficoll and uropoline from blood obtained on ACD fluid and on heparin. Isolation of lymphocytes from the blood obtained on heparin was more efficient (60%) and useful. For removal of platelets it was necessary to use additional centrifugation in a saccharose gradient or application of aggregating agents during isolation of lymphocytes obtained on heparin or ACD fluid.