Biodegradability and waste behavior of industrial wood-based construction materials

Industrial wood-based construction materials: chipboard, plain and overlaid plywood, phenolic surface film, laminates and selected synthetic polymers were studied for their biodegradability under aerobic and anaerobic conditions and for the environmental quality of the degradation residue. The yields of carbon dioxide plus methane from the wood-based materials in 6 months under anaerobic conditions at 33°C ranged from ⩽3% to 79% compared to that obtained from starch, and under aerobic conditions from ⩽7% to 55% of that obtained from acetate, measured in 28 days at 25°C. The plywoods were more readily degraded under aerobic and anaerobic conditions. The microbes attacked mainly the S₂-layer of the plywoods and started from the S₃-layer of the wood cells of chipboard in the compost. Extensive cavities, occupied with microbes, were observed by electron microscopy in the decaying plywoods, chipboard and laminates. The contents of Cu, Cr, Pb, Ni, and Cd of the wood-based construction materials were low, <10 mg kg⁻¹, compared to PVC and to a typical municipal solid waste. Toxicity and the amount of leachable organic halogen from the wood-based construction materials were low, EC₅₀ of 4–8 g L⁻¹ to V. fischeri and <12 μg adsorbable organic halogen (aox) of g⁻¹. The results show that the wood-based construction materials studied were aerobically biodegradable and the plywoods also anaerobically. There was no toxicity towards photobacteria or substances of environmental concern in the biodegradation and incineration residues of the materials tested. Journal of Industrial Microbiology & Biotechnology (2000) 24, 210–218. Received 08 September 1999/ Accepted in revised form 10 December 1999     

Dechlorination of pentachlorophenol by membrane bound enzymes of Rhodococcus chlorophenolicus PCP-I

Dechlorination (para-hydroxylation) of pentachlorophenol (PCP) and tetrachloro-para-hydroquinone (TeCH) and O-methylation of TeCH were demonstrated in cell extracts of Rhodococcus chlorophenolicus PCP-I. PCP para-hydroxylating activity was membrane bound, whereas TeCH dechlorinating enzyme was soluble. The PCP para-hydroxylating enzyme was solubilized by Triton X-100 and the requirement for both FAD and NADPH was shown. The dechlorinating activities were inducible in contrast to the constitutive TeCH O-methylating activity. The PCP para-hydroxylation was inhibited by its product TeCH, by anoxic conditions, and by different inhibitors of P₄₅₀. Participation of this cytochrome in the PCP hydroxylation was confirmed by the appearance of a carbon monoxide dependent peak of absorbance at 457 nm in the membrane fraction prepared from PCP degrading cells.     

Peripheral blood leukocytes of cows with subclinical endometritis show an altered cellular composition and gene expression

Subclinical endometritis (SCE) is an important postpartum disease in dairy cows, but conventional cytobrush diagnosis often gives imprecise results. The aim of this study was to analyze disease-associated changes in peripheral blood as potential diagnostic parameters. Cellular subpopulations of blood leukocytes from cows with or without SCE (45–55 days postpartum) were flow-cytometrically quantified. Gene expression of whole blood leukocytes was assessed by PAXgene analysis. Subclinical endometritis cows showed significantly higher number of blood mononuclear cells and neutrophils. Among mononuclear cells, numbers of B-cells, NK-cells, and CD172a-positive monocytes were significantly elevated. Compared with non-SCE cows, blood leukocytes of SCE cows significantly expressed higher copy numbers of CXCL8, TNF, and IL12. To test whether circulating plasma factors are responsible for these changes, leukocytes, polymorphonuclear cells, and monocyte subpopulations (classical, intermediate, nonclassical) of healthy cows were stimulated with plasma of SCE and non-SCE cows. Although gene expression of whole leukocytes and polymorphonuclear cells remained unaltered, plasma from SCE animals significantly elevated expressed messenger RNA copy numbers of CXCL8, CXCL1, and IL1B in intermediate monocytes. In conclusion, elevated number of selected mononuclear subpopulations in peripheral blood and enhanced expression of distinct genes encoding for inflammatory mediators in blood leukocytes reflect the subclinical uterine inflammatory process in cows. Whether the observed changes in the periphery of SCE cows are the consequence of the uterine inflammatory process, or whether they affect the pathogenesis of the disease is currently unknown.     

Toxic Bacillus pumilus from indoor air, recycled paper pulp, Norway spruce, food poisoning outbreaks and clinical samples

Forty-four B. pumilus isolates of food poisoning, clinical, environmental and industrial origins were investigated for toxin production using the boar spermatozoan motility assay, previously shown to be a sensitive method for detecting non-protein toxins from B. cereus and B. licheniformis. The three toxic isolates originated from live tree, indoor air and recycled paper pulp and were more toxic than the previously described food poisoning isolates of B. licheniformis, whereas the B. pumilus food poisoning and clinical isolates were lower in toxicity. The type strain also produced inhibitory substances. The toxic substances were insensitive to heat (100 degrees C, 20 min), to pH 2 or pH 10 and to digestion with pronase. The substances were readily soluble in methanol and chloroform, but less soluble in toluene. Exposure of boar spermatozoa to 1-10 microg ml(-1) (EC50) of methanol soluble substance from the four strains disrupted the plasma membrane permeability barrier, induced abnormalities in the postacrosomal sheath, collapsed the mitochondrial and suppressed cytoplasmic NAD reduction. No change was observed in human peripheral blood lymphocytes exposed to concentrations of B. pumilus extract that affected spermatozoa. The toxin producing isolates were 99.4 to 99.6% similar in 16SrDNA (500 bp) to the type strain and could not be distinguished from the 41 non-toxic isolates by biochemical properties or whole cell fatty acid composition.     

Bacillus subtilis and B. mojavensis strains connected to food poisoning produce the heat stable toxin amylosin

Aim:  To screen and characterize toxic, heat-stable substances produced by food borne strains from Bacillus subtilis group.
Methods and Results:  Using the boar sperm motility inhibition assay, six isolates from two outbreaks, out of the 94 isolates from 26 foods, were found to produce ethanol-soluble heat-stable substances that were toxic to sperm cells by depleting the mitochondrial membrane potentials. The toxic isolates were identified as Bacillus subtilis and B mojavensis. Colon carcinoma cells (Caco-2) were used to model the contact with the human digestive tract. The extract of B. subtilis F 2564/96 depolarized the mitochondria in intact Caco-2 cells similarly as in sperm cells. The substance responsible for these effects was purified using HPLC and identified by electron spray ionization ion trap mass spectrometry analysis as amylosin. The temperature requirement for amylosin production was 21–37°C for B. subtilis and 11–21°C for B. mojavensis . Both species produced amylosin in air as well as in 7–8% CO₂ with 8–9% O_2.
Conclusions:  Food borne illness related strains of B. subtilis and B. mojavensis, produced the heat-stable toxin amylosin.
Significance and Impact of the Study:  This is the first report that suggests a role for the heat-stable, ion-channel forming toxin amylosin, as a virulence factor in food borne Bacillus .     

16S rRNA targeted sandwich hybridization method for direct quantification of mycobacteria in soils

Boreal soils have been suspected reservoirs of infectious environmental mycobacteria. Detection of these bacteria in the environment is hampered by their slow growth. We applied a quantitative sandwich hybridization approach for direct detection of mycobacterial 16S rRNA in soil without a nucleic acid amplification step. The numbers of mycobacterial 16S rRNA molecules found in the soil indicated the presence of up to 10(7) to 10(8) mycobacterial cells per gram of soil. These numbers exceed by factor of 10 to 100 x the previous estimates of mycobacteria in soil based on culture methods. When real-time PCR with mycobacteria targeting primers was used to estimate the number of 16S rDNA copies in soil, one copy of 16S rDNA was detected per 10(4) copies of 16S rRNA. This is close to the number of 16S rRNA molecules detected per cell by the same method in laboratory pure cultures of M. chlorophenolicum. Therefore a major part of the mycobacterial DNA in the studied soils may thus have represented metabolically active cells. The 16S rRNA sandwich hybridization method described in this paper offers a culture independent solution for tracking environmental reservoirs of viable and potentially infectious mycobacteria.     

The thioredoxin system in aging muscle: key role of mitochondrial thioredoxin reductase in the protective effects of caloric restriction?

Cellular redox balance is maintained by various antioxidative systems. Among those is the thioredoxin system, consisting of thioredoxin, thioredoxin reductase, and NADPH. In the present study, we examined the effects of caloric restriction (2 mo) on the expression of the cytosolic and mitochondrial thioredoxin system in skeletal muscle and heart of senescent and young rats. Mitochondrial thioredoxin reductase (TrxR2) is significantly reduced in aging skeletal and cardiac muscle and renormalized after caloric restriction, while the cytosolic isoform remains unchanged. Thioredoxins (mitochondrial Trx2, cytosolic Trx1) are not influenced by caloric restriction. In skeletal and cardiac muscle of young rats, caloric restriction has no effect on the expression of thioredoxins or thioredoxin reductases. Enforced reduction of TrxR2 (small interfering RNA) in myoblasts under exposure to ceramide or TNF-alpha causes a dramatic enhancement of nucleosomal DNA cleavage, caspase 9 activation, and mitochondrial reactive oxygen species release, together with reduced cell viability, while this TrxR2 reduction is without effect in unstimulated myoblasts under basal conditions. Oxidative stress in vitro (H2O2 in C2C12 myoblasts and myotubes) results in different changes: TrxR2, Trx2, and Trx1 are induced without alterations in the cytosolic thioredoxin reductase isoforms. Thus aging is associated with a TrxR2 reduction in skeletal muscle and heart, which enhances susceptibility to apoptotic stimuli but is renormalized after short-term caloric restriction. Exogenous oxidative stress does not result in these age-related changes of TrxR2.     

The incidence and survival of acute de novo leukemias in Estonia and in a well-defined region of western Sweden during 1997–2001: A survey of patients aged ≥65 years

Background: In a recently published retrospective population-based study over three 5-year periods (1982–1996) we investigated the outcome for de novo acute leukemia (AL) patients aged ≥65 years at diagnosis in Estonia (a country that had been occupied by the Soviet Union over 5 decades) and in the so-called Western Swedish Health Care Region. The age-standardized yearly incidence rates regarding the total number of de novo AL was 5.3/100 000 inhabitant for Estonia and 8.0 for Sweden, this difference being statistically significant merely as regards acute myeloid leukemia (AML). The relative survival for the total cohort of de novo AL as well as for de novo AML was significantly longer (p < 0.001) for Swedish as compared to Estonian patients. Methods: In view of the miserable outcome for the Estonian patients we decided to prospectively compare the results for incidence and outcome of de novo AL between the two countries. Results: The present report covers the first 5-year period comprising 1997–2001 and deals only with patients aged ≥65 years at diagnosis. The age-adjusted annual incidence rates for de novo AML were lower in Estonia (6.4/100 000) than in Sweden (9.2/100 000) but not significantly so. The present results also show that the outcome for the Estonian AML patients had improved considerably over the study period; thus, at no time point, i.e., at 1, 3 and 5 years did relative survival between the two countries differ significantly. Conclusion: Yet, as compared to the Swedish cohort relative survival for the Estonian patients did still not reach an acceptable level.     

Effects of Increased Von Willebrand Factor Levels on Primary Hemostasis in Thrombocytopenic Patients with Liver Cirrhosis

In patients with liver cirrhosis procoagulant and anticoagulant changes occur simultaneously. During primary hemostasis, platelets adhere to subendothelial structures, via von Willebrand factor (vWF). We aimed to investigate the influence of vWF on primary hemostasis in patients with liver cirrhosis. Therefore we assessed in-vitro bleeding time as marker of primary hemostasis in cirrhotic patients, measuring the Platelet Function Analyzer (PFA-100) closure times with collagen and epinephrine (Col-Epi, upper limit of normal ≤165 s) or collagen and ADP (Col-ADP, upper limit of normal ≤118 s). If Col-Epi and Col-ADP were prolonged, the PFA-100 was considered to be pathological. Effects of vWF on primary hemostasis in thrombocytopenic patients were analyzed and plasma vWF levels were modified by adding recombinant vWF or anti-vWF antibody. Of the 72 included cirrhotic patients, 32 (44.4%) showed a pathological result for the PFA-100. They had mean closure times (± SD) of 180±62 s with Col-Epi and 160±70 s with Col-ADP. Multivariate analysis revealed that hematocrit (P = 0.027) and vWF-antigen levels (P = 0.010) are the predictors of a pathological PFA-100 test in cirrhotic patients. In 21.4% of cirrhotic patients with platelet count ≥150/nL and hematocrit ≥27.0%, pathological PFA-100 results were found. In thrombocytopenic (<150/nL) patients with cirrhosis, normal PFA-100 results were associated with higher vWF-antigen levels (462.3±235.9% vs. 338.7±151.6%, P = 0.021). These results were confirmed by multivariate analysis in these patients as well as by adding recombinant vWF or polyclonal anti-vWF antibody that significantly shortened or prolonged closure times, respectively. In conclusion, primary hemostasis is impaired in cirrhotic patients. The effect of reduced platelet count in cirrhotic patients can at least be partly compensated by increased vWF levels. Recombinant vWF could be an alternative to platelet transfusions in the future.