Isolation of a YAC clone covering a cluster of nine S100 genes on human chromosome 1q21: rationale for a new nomenclature of the S100 calcium-binding protein family

S100 proteins are low-molecular-weight calcium-binding proteins of the EF-hand superfamily and appear to be involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. More than 10 members of the S100 protein family have been described from human sources so far. We have now isolated a YAC clone from human chromosome 1q21, on which 9 different genes coding for S100 calcium-binding proteins could be localized. Moreover, we have mapped the gene coding for S100P to human chromosome 4p16 and thereby completed the chromosomal assignments of all known human S100 genes. The clustered organization of S100 genes in the 1q21 region allows us to introduce a new logical nomenclature for these genes, which is based on the physical arrangement on the chromosome. The new nomenclature should facilitate and further the understanding of this protein family and be easily expandable to other species.     

Stoichiometry and kinetics of microbial toluene degradation under denitrifying conditions

Batch experiments were carried out to investigate the stoichiometry and kinetics of microbial degradation of toluene under denitrifying conditions. The inoculum originated from a mixture of sludges from sewage treatment plants with alternating nitrification and denitrification. The culture was able to degrade toluene under anaerobic conditions in the presence of nitrate, nitrite, nitric oxide, or nitrous oxide. No degradation occurred in the absence of Noxides. The culture was also able to use oxygen, but ferric iron could not be used as an electron acceptor. In experiments with¹⁴C-labeled toluene, 34%±8% of the carbon was incorporated into the biomass, while 53%±10% was recovered as¹⁴CO₂, and 6%±2% remained in the medium as nonvolatile water soluble products. The average consumption of nitrate in experiments, where all the reduced nitrate was recovered as nitrite, was 1.3±0.2 mg of nitrate-N per mg of toluene. This nitrate reduction accounted for 70% of the electrons donated during the oxidation of toluene. When nitrate was reduced to nitrogen gas, the consumption was 0.7±0.2 mg per mg of toluene, accounting for 97% of the donated electrons. Since the ammonia concentration decreased during degradation, dissimilatory reduction of nitrate to ammonia was not the reductive process. The degradation of toluene was modelled by classical Monod kinetics. The maximum specific rate of degradation, k, was estimated to be 0.71 mg toluene per mg of protein per hour, and the Monod saturation constant, K _s , to be 0.2 mg toluene/l. The maximum specific growth rate, _max , was estimated to be 0.1 per hour, and the yield coefficient, Y, was 0.14 mg protein per mg toluene.Abbreviations NVWP Non Volatile Water-soluble Products     

Prevalence of Alzheimer's disease and vascular dementia: association with education. The Rotterdam study.

OBJECTIVE--To estimate the prevalence of dementia and its subtypes in the general population and examine the relation of the disease to education. DESIGN--Population based cross sectional study. SETTING--Ommoord, a suburb of Rotterdam. SUBJECTS--7528 participants of the Rotterdam study aged 55-106 years. RESULTS--474 cases of dementia were detected, giving an overall prevalence of 6.3%. Prevalence ranged from 0.4% (5/1181 subjects) at age 55-59 years to 43.2% (19/44) at 95 years and over. Alzheimer''s disease was the main subdiagnosis (339 cases; 72%); it was also the main cause of the pronounced increase in dementia with age. The relative proportion of vascular dementia (76 cases; 16%), Parkinson''s disease dementia (30; 6%), and other dementias (24; 5%) decreased with age. A substantially higher prevalence of dementia was found in subjects with a low level of education. The association with education was not due to confounding by cardiovascular disease. CONCLUSIONS--The prevalence of dementia increases exponentially with age. About one third of the population aged 85 and over has dementia. Three quarters of all dementia is due to Alzheimer''s disease. In this study an inverse dose-response relation was found between education and dementia--in particular, Alzheimer''s disease.     

Conversion of cephalosporin-c into 7-phenoxy-acetamido-cephalosporanic acid by acyltransferase of mutants of Penicillium chrysogenum

Summary We have tested the acyl-transferase of penicillin producing strains and penicillin-less mutants of Penicillium chrysogenum for their ability to exchange the d--aminoadipic acid side chain of cephalosporin-C with phenoxyacetic acid. We found the reaction in both types of strains.     

Isolation and characterization of the outer membrane of Acinetobacter calcoaceticus

A method for the separation of the outer membrane (OM) from the cytoplasmic membrane (CM) of Acinetobacter calcoaceticus 69/V grown on different carbon sources is described. The contamination of the OM with CM was less than 10%. Independent of the carbon source, five protein bands with apparent molecular weights of 47 000, 33000, 21 000, 19 000 and 12 000 were found by solubilization at 37°C and six bands at 100°C (apparent M_r 53 000, 47 000, 38 000, 26 000, 21000, 12000). Three proteins were modifiable by heat. With the periodic acid-Schiff procedure the bands with apparent M_r of 33 000 and 12 000 were made visible. After growth on d,l-carnitine an additional two non-heat-modifiable protein bands with apparent M_r between 40 000 and 45 000 were detected. By cultivation on acetate and peptone as carbon source one additional band (M_r 15 000) from OM of cells could be found.     

Thyroglobulin structure-function: the effect of iodination on the structure of human thyroglobulin

Thyroglobulin of very low iodine content has been prepared from a single non-toxic human goitre. The initial iodine content of the protein (0.038%) has been increased to levels of 0.16% and 0.85% by in vitro treatment with thyroid peroxidase and the resulting proteins studied with respect to their intrinsic fluorescence, circular dichroism spectra and binding of the hydrophobic probe 1,8-anilinonaphthalene sulfonic acid (ANS). While significant differences were observed between levels of iodination in both the ANS binding and intrinsic fluorescence of the thyroglobulin, no significant differences in the near and far UV circular dichroism spectra of the protein as a function of iodine content were observed. These data suggest that, the iodination of thyroglobulin effects specific areas of the protein without significant disruption of its overall secondary structure.     

Familial pericentric inversion of the X chromosome [inv(X)(p11q28)]

A familial pericentric inversion of the X chromosome [46,X,inv(X)(p11q28)] and [46,inv(X)(p11q28), Y] is reported. The carriers of the inv(X) presented no clinical symptoms. Either the inverted or the normal X chromosome may be late replicating.     

Changes in key regulatory enzymes of hepatic carbohydrate metabolism after glucose loading of starved rats

When glucose was given to starved rats there was an increase in both 6-phosphofructo 2-kinase and pyruvate kinase activity and a decrease in fructose 2,6-bisphosphatase activity 30 min and 60 min later. These changes were accompanied by an increase in glycogen deposition and by modest, but significant increases in fructose 2,6-bisphosphate levels at the same time. Metabolite measurements indicated that flux through 6-phosphofructo 1-kinase and pyruvate kinase were increased. These results suggest that although glycogen deposition may occur via the gluconeogenic pathway, glycolysis is activated at the same time by changes in the phosphorylation state of key regulatory enzymes as well as by the small rise in fructose 2,6-bisphosphate.     

Convenient procedures for the biosynthesis, isolation, and isotope labeling of cytochalasins.

Efforts to improve small-scale yields of useful cytochalasins by fermentation resulted in selection of an enriched aflatoxin medium which increased yields by fivefold over those reported in the literature. With Helminthosporium dematoideum and Zygosporium masonii in stationary culture for 3 weeks, cytochalasins B and D were obtained in quantities approaching 700 and 500 mg/liter, respectively. It appears that the critical component in this growth medium is factors associated with whole wheat. By using these procedures, coupled with improvements in isolation, supplementation with two radioactive phenylalanine species readily produced [14C]- or [3H]cytochalasin B. Oxidation of carrier-free radioactive cytochalasin B to cytochasasin A readily provided this labeled congener as well. The isotopic ocnversion of precursor to crystalline products that met analytical criteria ranged from 2 to 4% of the administered radioactivity.     

ACTIVITY AND ISOENZYME PATTERN OF LACTATE DEHYDROGENASE IN ASTROBLASTS CULTURED FROM BRAINS OF NEWBORN MICE

Lactate dehydrogenase activity and isoenzyme distribution was determined in primary cultures of astroblasts as a function of the culture period. The specific activity increased during this period with a peak value (1.91 ± 0.18μmol x min^-1 x mg^-1 cell protein) after 2 weeks in culture. The isoenzyme pattern changed during 3 weeks in culture towards a higher proportion of the H₄ (LDH-1) isoenzyme which is analogous to the in vivo pattern. Omission of serum with or without dBcAMP (0.5 mM) in the culture medium during the third week of culture further enhanced this prominence of the H₄ isoenzyme. The specific activity (1.58 × 0.06 μmol x min^-1 x mg^-1 cell protein) of cultures grown in the presence of 0.5 mM-dBcAMP and absence of serum was close to the activity in the adult brain.