Insulin-like growth factor binding protein-3 in patients with liver cirrhosis

Aim of the study was to evaluate serum levels of insulin-like growth factor binding protein-3 in patients with liver cirrhosis and to compare serum IGFBP-3 levels with other liver function tests. Fifty-one patients with liver cirrhosis were selected for our study. We measured IGFBP-3 (1.67+/-1.06 mg/l, mean+/-SD), albumin (32+/-8 g/l), prealbumin (0.22+/-0.14 g/l), AST (2.29+/-2.38 microkat/l), ALT (2.11+/-4.83 microkat/l) and cholinesterase (mean 78.6+/-45.2 microkat/l) in the serum. There was a significant positive correlation of serum IGFBP-3 with serum albumin and serum cholinesterase. The correlation coefficient was much lower between serum IGFBP-3 and serum prealbumin. There was no significant correlation between serum AST, ALT and IGFBP-3. Serum IGFBP-3 proves to be a better marker for the hepatic synthetic capacity than serum albumin or cholinesterase.     

A novel pathway for mineralization of the thiocarbamate herbicide molinate by a defined bacterial mixed culture

A bacterial mixed culture able to mineralize molinate was established, through enrichment, using mineral medium with molinate as the only carbon, nitrogen and energy source. The combination of five cultivable isolates, purified from the enrichment culture, permitted the reconstitution of a degrading consortium. Both enrichment and defined cultures were able to mineralize molinate without accumulation of degradation products by the end of the growth. Among the five isolates constituting the defined mixed culture, an actinomycete, strain ON4, was essential for biodegradation, being involved in the cleavage of the thioester bond of molinate, the initial step of the degradation pathway. Isolate ON4 was able to grow on molinate at concentrations below 2 mM, with the accumulation of ethanethiol and diethyl disulphide. These sulphur compounds were toxic to strain ON4 when accumulating at higher concentrations. However, this inhibitory effect was avoided by the presence of other members of the mixed culture, out of which isolates ON1 and ON2 were observed to consume ethanethiol and diethyl disulphide. In this way, interactions among defined mixed culture members involve metabolic and detoxifying association.     

Molecular phylogeny of date palm (Phoenix dactylifera L.) cultivars from Saudi Arabia by DNA fingerprinting

Genetic diversity among 13 different cultivars of date palm (Phoenix dactylifera L.) of Saudi Arabia was studied using random amplified polymorphic DNA (RAPD) markers. The screening of 140 RAPD primers allowed selection of 37 primers which revealed polymorphism, and the results were reproducible. All 13 genotypes were distinguishable by their unique banding patterns produced by 37 selected primers. Cluster analysis by the unweighted paired group method of arithmetic mean (UPGMA) showed two main clusters. Cluster A consisted of five cultivars (Shehel, Om-Kobar, Ajwa, Om-Hammam and Bareem) with 0.59–0.89 Nei and Li's coefficient in the similarity matrix. Cluster B consisted of seven cultivars (Rabeeha, Shishi, Nabtet Saif, Sugai, Sukkary Asfar, Sukkary Hamra and Nabtet Sultan) with a 0.66–0.85 Nei and Li's similarity range. Om-Hammam and Bareem were the two most closely related cultivars among the 13 cultivars with the highest value in the similarity matrix for Nei and Li's coefficient (0.89). Ajwa was closely related with Om-Hammam and Bareem with the second highest value in the similarity matrix (0.86). Sukkary Hamra and Nabtet Sultan were also closely related, with the third highest value in the similarity matrix (0.85). The cultivar Barny did not belong to any of the cluster groups. It was 34% genetically similar to the rest of the 12 cultivars. The average similarity among the 13 cultivars was more than 50%. As expected, most of the cultivars have a narrow genetic base. The results of the analysis can be used for the selection of possible parents to generate a mapping population. The variation detected among the closely related genotypes indicates the efficiency of RAPD markers over the morphological and isozyme markers for the identification and construction of genetic linkage maps.Communicated by H.F. Linskens     

Metabolic pathway for propionate utilization by phosphorus-accumulating organisms in activated sludge: 13C labeling and in vivo nuclear magnetic resonance

In vivo 13C and 31P nuclear magnetic resonance techniques were used to study propionate metabolism by activated sludge in enhanced biological phosphorus removal systems. The fate of label supplied in [3-13C]propionate was monitored in living cells subjected to anaerobic/aerobic cycles. During the anaerobic phase, propionate was converted to polyhydroxyalkanoates (PHA) with the following monomer composition: hydroxyvalerate, 74.2%; hydroxymethylvalerate, 16.9%; hydroxymethylbutyrate, 8.6%; and hydroxybutyrate, 0.3%. The isotopic enrichment in the different carbon atoms of hydroxyvalerate (HV) produced during the first anaerobic stage was determined: HV5, 59%; HV4, 5.0%; HV3, 1.1%; HV2, 3.5%; and HV1, 2.8%. A large proportion of the supplied label ended up on carbon C-5 of HV, directly derived from the pool of propionyl-coenzyme A (CoA), which is primarily labeled on C-3; useful information on the nature of operating metabolic pathways was provided by the extent of labeling on C-1, C-2, and C-4. The labeling pattern on C-1 and C-2 was explained by the conversion of propionyl-CoA to acetyl-CoA via succinyl-CoA and the left branch of the tricarboxylic acid cycle, which involves scrambling of label between the inner carbons of succinate. This constitutes solid evidence for the operation of succinate dehydrogenase under anaerobic conditions. The labeling in HV4 is explained by backflux from succinate to propionyl-CoA. The involvement of glycogen in the metabolism of propionate was also demonstrated; moreover, it was shown that the acetyl moiety to the synthesis of PHA was derived preferentially from glycogen. According to the proposed metabolic scheme, the decarboxylation of pyruvate is coupled to the production of hydrogen, and the missing reducing equivalents should be derived from a source other than glycogen metabolism.     

The contribution of photosynthetic pigments to the development of biochemical separation methods: 1900–1980

The role of photosynthetic pigments in the development of separation methods in biochemistry during the period 1900-1980 is described beginning with M. Tswett who introduced separation of chlorophylls and carotenoids on columns and coined the term chromatography in 1906. In Uppsala, T. Svedberg developed the ultracentrifuge in the 1920s. A. Tiselius improved electrophoresis in the 1930s and developed chromatography of proteins in the 1940s and 1950s. Others of 'The Uppsala school in separation science' include J. Porath, P. Flodin and S. Hjertén who further developed various gel chromatographic methods. Hjertén introduced free zone electrophoresis in narrow tubes, a forerunner of capillary electrophoresis. Two proteins, phycoerythrin and phycocyanin, were used as test substances in all these methodological studies. Aqueous two-phase partitioning as a separation method was introduced in 1956 by the author. In this work, chloroplast particles were used, and the method was applied for the separation and purification of intact chloroplasts, inside-out thylakoid vesicles and plasma membranes. My research was carried out in cooperation with G. Blomquist, G. Johansson, C. Larsson, B. Andersson and H.-E. Akerlund during a 20-year period, 1960-1980.     

Conformational stability and normal coordinate analyses for 1-halovinyl azides CH<Subscript>2</Subscript>=CX–NNN (X is F,Cl and Br)

The conformational behavior of 1-halovinyl azides CH2=CX-NNN (X=F, Cl and Br) were investigated by DFT-B3LYP and ab initio MP2 calculations with the 6-311++G** basis set. The molecules were predicted to exist predominantly in the trans (the vinyl CH2=CH- and the azide -NNN groups are trans to each other) conformation. The relative energy between cis and trans were calculated to decrease in order: bromide>chloride>fluoride. Full optimization was performed at the ground and transition states in the molecule at both MP2 and B3LYP levels. The barrier to internal rotation around the C-N single bond in the three molecules was calculated to be about 4-5 kcal mol(-1). The vibrational frequencies were computed at the DFT-B3LYP level and the calculated infrared and Raman spectra of the cis- trans mixture of the three molecules were plotted. Complete vibrational assignments were made on the basis of normal coordinate calculations for both stable conformers of the three molecules.     

Immunocytolocalization of tryptophan decarboxylase in Catharanthus roseus hairy roots

We investigated the intracellular distribution of tryptophan decarboxylase (TDC) (EC 4.1.1.28) in Catharanthus roseus hairy roots using immunofluorescence and immunogold techniques. TDC was detected by immunofluorescence localization in the cytosol and in the apoplastic region of the meristematic cells of the roots, with a slight enrichment in the epidermal cells of the root cap and in the meristematic region. In the enlargement zone, TDC was localized only in the first three layers of the cortex. In the maturation zone, the enzyme was not present. Immunogold studies confirmed that the enzyme was localized in the cytosol of the meristematic region, and intense gold labeling was found in the apoplastic zone. A protein fraction isolated from the apoplastic zone and assayed for TDC activity showed high activity.     

Expression and distribution of carboxypeptidase B in the hippocampal subregions of normal and Alzheimer's disease brain

Earlier neurochemical studies suggested that human brain carboxypeptidase B may play a significant role in the degradation of amyloid-beta1-42 in the brain. Using an immimohistochemical technique we report here on the neuronal expression and distribution of this enzyme in the segments (CA1a, CA1b and CA1c) of the CA1 subfield and in area CA4 of the hippocampus in normal and Alzheimer's disease brain samples. Its distribution was compared with the appearance of neurofibrillary tangles in the same brain sample. For immunohistochemical localization of carboxypeptidase B, a specific C14-module antibody was applied, together with the Gallyas silver impregnation technique for the demonstration of neurofibrillary tangles. The results revealed that, in the control samples, most of the immunoreactivity appeared in segment CA1a in the pyramidal cells, less in segment CA1b and least in segment CA1c. In the Alzheimer's disease samples, there was no particular immunostaining in the neurons, but, a large number of silver-impregnated degenerated neurons appeared. The results support the suggestion that carboxypeptidase B may play a significant role in elimination of the intracellular accumulation and toxicity of amyloid-beta in the human brain and thereby protect the neurons from degeneration.     

Lactobacillus acidophilus Autolysins Inhibit Helicobacter pylori In Vitro

Antibacterial activity of 17 strains of lactobacilli was tested against 10 strains of H. pylori. The inhibition observed was related to the acid production and the low pH attained. No relationship between CagA phenotype of H. pylori strains and tolerance to lactic acid was observed. In mixed cultures, L. acidophilus CRL 639 showed an autolytic behavior after 24 h of culture. At this moment, H. pylori CCUG17874 showed a decrease of 2 log-cycle, and no viable count was detected after 48 h. The bactericidal effect of L. acidophilus CRL 639 in mixed cultures is related to a proteinaceous compound released after cell lysis. Received: 19 June 2000 / Accepted: 12 July 2000