Production and Partial Purification of Antibiotic Materials Formed by Physarum gyrosum

Pure cultures of Physarum gyrosum were grown on agar plates with autoclaved Escherichia coli suspensions as the growth medium. Portions of such agar, after growth of the slime mold, contained diffusible materials that inhibited the growth of Bacillus subtilis, B. cereus, E. coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Paper chromatography of extracts of such cultures revealed at least three different active fractions. Preliminary fractionations increased the specific activity by one order of magnitude, probably in part by removal of inactive material and in part by separating active components. The fractionations also demonstrated the multiplicity of the antibiotic activity. Fractions variously obtained always retarded the growth of the bacterial species listed above.     

Luciferin derivatives in bioluminescence-enhanced enzyme immunoassays

Ultrasensitive bioluminescence immunoassays for the determination of peptides and proteins (illustrated with human urinary kallikrein, bradykinin and the determination of human urinary kallikrein antibody titres) have been developed. The usable ranges of the standard curves are from 5 pg to 5000 pg per litre. The relative intra-assay coefficients of variation of the tests were between 2% and 6%, and the inter-assay coefficients of variation between 4% and 12%.     

Linkage of PGK1 to X-linked severe combined immunodeficiency (IMD4) allows predictive testing in families with no surviving male

Summary We present a linkage map of DNA probes around the X-linked severe combined immunodeficiency (IMD4) locus at Xq11-13. DXS159 and PGK1 show no cross-overs with the disease locus (Lod 3.01 at = 0.00). The order of loci is DXS1-DXS106-(DXS159-PGK1-IMD4)-DXS72-DXYS1. Members of families whose carrier status has been established by X-inactivation patterns were included in the analysis. As the probe (pSPT/PGK), which is used for investigation of X-inactivation patterns, has been shown to be linked to the disease itself, it is possible to assign phase in mothers of sporadic cases who have been shown to be carriers, even when they have no surviving male offspring.     

City spore concentrations in the European Economic Community (EEC). VI. Poaceae (Grasses), 1982–1986

Summary Airborne grass-pollen concentrations in six cities in the EEC are compared, based on observations from five years, 1982–1986. Results show that there are quantitative differences both between the monitoring stations and between the years. Very provisionally, the average seasonal total of the European urban airborne grass-pollen concentration can be put at 4 to 5000 per m³ of air. Also qualitatively, regarding the seasonal fluctuations, there are differences between the stations, and between the years. Generally, the results confirm that June is the most typical grass-pollen month in northwestern Europe, whereas in mediterranean Europe May is the more prominent grass-pollen period. There seems to be little coherence between the starting dates of the grass-pollen season even at relatively nearby stations in northwestern Europe, suggestive for a great influence of the actual weather situation.     

Characterization of Cellular Transport, Subcellular Distribution, and Secretion of the Neurotoxicant 1-Methyl-4-Phenylpyridinium in Bovine Adrenomedullary Cell Cultures

Cultures of bovine adrenomedullary chromaffin cells accumulated 1-[methyl-3H]methyl-4-phenylpyridinium ([3H]MPP+) in a time- and concentration-dependent manner with an apparent Km of 0.7 microM and a Vmax of 3 pmol/min/10(6) cells. The uptake was sodium dependent and sensitive to inhibitors of the cell-surface catecholamine transporter. At low concentrations of MPP+, the subcellular distribution was identical to that of endogenous catecholamines in the catecholamine-containing chromaffin vesicles. However, at a higher concentration of MPP+, a larger proportion of the toxicant was recovered in the cytosolic fraction, with less in the chromaffin vesicle fractions. When cells were prelabeled with [3H]MPP+, at 1 and 300 microM, and then permeabilized with digitonin in the absence of Ca2+, there was a proportionally greater release of MPP+ from the cells labeled at the higher concentration of the toxicant. In the presence of Ca2+, cell permeabilization induced a time-dependent secretion of catecholamines and a parallel secretion of MPP+. Under these conditions, the secretion of endogenous catecholamines was unaffected by the presence of MPP+. When the permeabilization studies were carried out in the presence of tetrabenazine, a massive release of MPP+ was observed in the absence of Ca2+ and was not further increased by Ca2+. In intact cells prelabeled with 300 microM [3H]MPP+, the secretagogues nicotine and veratridine elicited a Ca2+ -dependent secretion of catecholamines and MPP+ from the cells in similar proportions to their cellular contents. Barium-induced release of both species was independent of external Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anaerobic degradation of toluene and xylene by aquifer microorganisms under sulfate-reducing conditions.

Toluene and the three isomers of xylene were completely mineralized to CO2 and biomass by aquifer-derived microorganisms under strictly anaerobic conditions. The source of the inoculum was gasoline-contaminated sediment from Seal Beach, Calif. Evidence confirming that sulfate was the terminal electron acceptor is presented. Benzene and ethylbenzene were not degraded under the experimental conditions used. Successive transfers of the mixed cultures that were enriched from aquifer sediments retained the ability to degrade toluene and xylenes. Greater than 90% of 14C-labeled toluene or 14C-labeled o-xylene was mineralized to 14CO2. The doubling time for the culture grown on toluene or m-xylene was about 20 days, and the cell yield was about 0.1 to 0.14 g of cells (dry weight) per g of substrate. The accumulation of sulfide in the cultures as a result of sulfate reduction appeared to inhibit degradation of aromatic hydrocarbons.     

Predation on Protozoa: its importance to zooplankton

Protozoa are an important component of both the nano- and microplanktonin marine and freshwater environments and are preyed upon byzooplankton, including suspension-feeding cope pods, some gelatinouszoopiankters and some first-feeding fish larvae. The clearancerates of suspension-feeding zooplankton for ciliates, in particular,are higher than for most phytoplankton. For at least some suspension-feedingzooplankton, protozoans are calculated to be quantitativelyan important component of the diet during certain seasons. Inlaboratory studies, protozoan components in the diet appearto enhance growth and survival of certain life-history stagesor enhance fecundity. These data suggest that protozoans arequalitatively as well as quantitatively important in the dietsof marine zooplankton. Most studies of predation on Protozoahave focused on the euphotic zone in nearshore waters. Predationon Protozoa is expected, however, to be particularly importantboth quantitatively and qualitatively in marine environmentsand seasons in which primary production is dominated by cells<5 µm in size, such as nearshore environments afterthe spring phytoplankton bloom, in oligotrophic waters, andin environments dominated by detritus-dominated food webs, suchas the deep sea. In detritus-dominated food webs, Protozoa maybe a source of essential nutrients and may thus facilitate utilizationof bacterial and detrital carbon by metazoan plankton.     

Initial reactions in anaerobic ethylbenzene oxidation by a denitrifying bacterium, strain EB1.

Initial reactions in anaerobic oxidation of ethylbenzene were investigated in a denitrifying bacterium, strain EB1. Cells of strain EB1 mineralized ethylbenzene to CO2 under denitrifying conditions, as demonstrated by conversion of 69% of [14C]ethylbenzene to 14CO2. In anaerobic suspensions of strain EB1 cells metabolizing ethylbenzene, the transient formation and consumption of 1-phenylethanol, acetophenone, and an as yet unidentified compound were observed. On the basis of growth experiments and spectroscopic data, the unknown compound is proposed to be benzoyl acetate. Cell suspension experiments using H2(18)O demonstrated that the hydroxyl group of the first product of anoxic ethylbenzene oxidation, 1-phenylethanol, is derived from water. A tentative pathway for anaerobic ethylbenzene mineralization by strain EB1 is proposed.     

Cloning and molecular analysis of the bifunctional dihydrofolate reductase-thymidylate synthase gene in the ciliated protozoanParamecium tetraurelia

We have cloned the first bifunctional gene dihydrofolate reductase-thymidylate synthase (DHFR-TS) from a free-living, ciliated protozoan,Paramecium tetraurelia, and determined its macronuclear sequence using a modified ligation-mediated polymerase chain reaction (PCR) that can be of general use in cloning strategies, especially where cDNA libraries are limiting. While bifunctional enzyme sequences are known from parasitic protozoa, none had previously been found in free-living protozoa. The AT-rich (68%) coding region spanning 1386 bp appears to lack introns. DHFR-TS localizes to a 500 kb macronuclear chromosome and is transcribed as an mRNA of 1.66 kb, predicted to encode a 53 kDa protein of 462 residues. The N-terminal one-third of the protein is encoded by DHFR, which is joined by a short junctional peptide of 12 amino acids to the highly conserved C-terminal TS domain. Among known DHFR-TS sequences, theP. tetraurelia gene is most similar to that fromToxoplasma gondii, based on primary sequence and parsimony analyses. The predicted secondary protein structure is similar to those of previously crystallized monofunctional sequences.