[Primary pulmonary hypertension].
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Humans↗
Biomedical subjects
A Konopka
Publications and source records attributed to A Konopka.
Inhibition of human immunodeficiency virus in early infected and chronically infected cells by antisense oligodeoxynucleotides and their phosphorothioate analogues.
Antisense oligodeoxynucleotides, both the phosphorothioate analogues and unmodified oligomers of the same sequence, inhibit replication and expression of human immunodeficiency virus already growing in tissue cultures of MOLT-3 cells with much greater efficacy than do mismatched ("random") oligomers and homooligomers of the same length and with the same internucleotide modification. This preferential inhibitory effect is elicited in as short a time as 4-24 hr postinfection. Likewise, antisense oligomers exhibit greater inhibitory effects on human immunodeficiency virus in chronically infected cells than do mismatched oligomers and homooligomers. Phosphorothioate antisene oligomers are up to 100 times more potent than unmodified oligomers of the same sequence in these inhibitory assays. These results, in major respects, confirm and extend those recently published by Matsukura et al. [Matsukura, M., Zon, G., Shinozuka, K., Robert-Guroff, M., Shimada, T., Stein, C. A., Mitsuza, H., Wong-Staal, F., Cohen, J. S. & Broder, S. (1989) Proc. Natl. Acad. Sci. USA 86, 4244-4248]. They also point out the importance of computer analysis of sequences though to be random but that in reality contain significant areas of likely hybridization, either to the viral genome or to the complementary DNA strand synthesized from it. They thus reinforce the concept that specific base pairing is a crucial feature of oligonucleotide inhibition of human immunodeficiency virus.
Antiviral Agents↗
Characterization of a Pseudomonas sp. Capable of Aniline Degradation in the Presence of Secondary Carbon Sources.
Pseudomonas strain K1 is a gram-negative rod which grows aerobically on minimal media containing aniline with a doubling time of 2 h at 30 degrees C. The half-saturation parameter for aniline metabolism by aniline-grown cells was 3.8 mumol . liter. Concentrations of aniline as low as 50 nM were metabolized. Neither substituted anilines nor other aromatic compounds (other than aromatic amino acids) supported growth. Cells grew as fast on aniline as on nonaromatic substrates such as lactate. The aromatic ring was cleaved via the meta pathway. Catechol 2,3-oxygenase activity was induced by aniline, even in cultures containing alternative carbon sources such as lactate. Cultures grown on a mixture of aniline and lactate mineralized aniline in the presence of the second substrate. Lactate-grown cultures lacked catechol oxygenase activity, and resting cells from these cultures did not respire aniline. Resting cells from aniline-grown cultures exhibited high respiratory activity upon the addition of aniline or catechol, some activity with toluidine, and no activity after addition of a wide variety of other aromatic compounds, including dihydroxybenzylamine, chloroanilines, ethylanilines, aminophenols, aminobenzoates, and dihydroxybenzoates. Although substituted anilines were not metabolized, 3-or 4-chloroaniline did induce the enzymes for aniline oxidation.
Journal Article↗
The 3'-orf protein of human immunodeficiency virus shows structural homology with the phosphorylation domain of human interleukin-2 receptor and the ATP-binding site of the protein kinase family.
The primary amino acid sequence within a stretch of 25 residues (positions 91-116) of the middle portion of the 3'-orf protein (p27(3')-orf) of the human immunodeficiency virus (HIV) shares structural homology with a highly charged region within the intracytoplasmic phosphorylation domain of human interleukin-2 receptor (IL-2R) and the ATP-binding site of the catalytic subunit of cAMP-dependent protein kinase (cAMP-PK) and other members of the protein kinase family. Comparison of the predicted secondary structure within this region of p27(3')-orf with the phosphorylation domain of human IL-2R and the ATP-binding region of the phospho-kinase family of protein suggests that the 3'-orf protein could serve homologous function(s).
Adenosine Triphosphate↗
Algal and Bacterial Activities in Acidic (pH 3) Strip Mine Lakes.
Reservoir 29 and Lake B are extremely acid lakes (epilimnion pHs of 2.7 and 3.2, respectively), because they receive acidic discharges from coal refuse piles. They differ in that the pH of profundal sediments in Reservoir 29 increased from 2.7 to 3.8 during the period of thermal stratification, whereas permanently anoxic sediments in Lake B had a pH of 6.2. The pH rise in Reservoir 29 sediments was correlated with a temporal increase in H(2)S concentration in the anaerobic hypolimnion from 0 to >1 mM. The chlorophyll a levels in the epilimnion of Reservoir 29 were low, and the rate of primary production was typical of an oligotrophic system. However, there was a dense 10-cm layer of algal biomass at the bottom of the metalimnion. Production by this layer was low owing to light limitation and possibly H(2)S toxicity. The specific photosynthetic rates of epilimnetic algae were low, which suggests that nutrient availability is more important than pH in limiting production. The highest photosynthetic rates were obtained in water samples incubated at pH 2.7 to 4. Heterotrophic bacterial activity (measured by [C]glucose metabolism) was greatest at the sediment/water interface. Bacterial production (assayed by thymidine incorporation) was as high in Reservoir 29 as in a nonacid mesotrophic Indiana lake.
Journal Article↗
Degradation of Pyridine by Micrococcus luteus Isolated from Soil.
An organism capable of growth on pyridine was isolated from soil by enrichment culture techniques and identified as Micrococcus luteus. The organism oxidized pyridine for energy and released N contained in the pyridine ring as ammonium. The organism could not grow on mono- or disubstituted pyridinecarboxylic acids or hydroxy-, chloro-, amino-, or methylpyridines. Cell extracts of M. luteus could not degrade pyridine, 2-, 3-, or 4-hydroxypyridines or 2,3-dihydroxypyridine, regardless of added cofactors or cell particulate fraction. The organism had a NAD-linked succinate-semialdehyde dehydrogenase which was induced by pyridine. Cell extracts of M. luteus had constitutive amidase activity, and washed cells degraded formate and formamide without a lag. These data are consistent with a previously reported pathway for pyridine metabolism by species of Bacillus, Brevibacterium, and Corynebacterium. Cells of M. luteus were permeable to pyridinecarboxylic acids, monohydroxypyridines, 2,3-dihydroxypyridine, and monoamino- and methylpyridines. The results provide new evidence that the metabolism of pyridine by microorganisms does not require initial hydroxylation of the ring and that permeability barriers do not account for the extremely limited range of substrate isomers used by pyridine degraders.
Journal Article↗
Primary and bacterial production in two dimictic indiana lakes.
The relationship between primary and bacterial production in two dimictic Indiana lakes with different primary productivities was examined during the summer stratification period in 1982. Primary production rates were calculated from rates of HCO(3) incorporation by natural samples, and bacterial production was calculated from rates of [H-methyl]thymidine incorporation by natural samples. Both vertical and seasonal distributions of bacterial production in the more productive lake (Little Crooked Lake) were strongly influenced by primary production. A lag of about 2 weeks between a burst in primary production and the subsequent response in bacterial production was observed. The vertical distribution of bacterial production in the water column of the less productive lake (Crooked Lake) was determined by the vertical distribution of primary production, but no clear relationship between seasonal maxima of primary and bacterial production in this lake was observed. High rates of bacterial production in Crooked Lake during May indicate the importance of allochthonous carbon washed in by spring rains. Bacterial production accounted for 30.6 and 31.8% of total (primary plus bacterial) production in Crooked Lake and Little Crooked Lake, respectively, from April through October. High rates of bacterial production during late September and October were observed in both lakes. Calculation of the fraction of bacterial production supported by phytoplankton excretion implies an important role for other mechanisms of supplying carbon, such as phytoplankton autolysis. Several factors affecting the calculation of bacterial production from the thymidine incorporation rates in these lakes were examined.
Journal Article↗
Seasonal bacterial production in a dimictic lake as measured by increases in cell numbers and thymidine incorporation.
Rates of primary and bacterial production in Little Crooked Lake were calculated from the rates of incorporation of HCO(3) and [methyl-H]thymidine, respectively. Growth rates of bacteria in diluted natural samples were determined for epilimnetic and metalimnetic bacterial populations during the summers of 1982 and 1983. Exponential growth was observed in these diluted samples, with increases in cell numbers of 30 to 250%. No lag was observed in bacterial growth in 14 of 16 experiments. Correlation of bacterial growth rates to corresponding rates of thymidine incorporation by natural samples produced a conversion factor of 2.2 x 10 cells produced per mole of thymidine incorporated. The mass of the average bacterial cell in the lake was 1.40 x 10 +/- 0.05 x 10 g of C cell. Doubling times of natural bacteria calculated from thymidine incorporation rates and in situ cell numbers ranged from 0.35 to 12.00 days (median, 1.50 days). Bacterial production amounted to 66.7 g of C m from April through September, accounting for 29.4% of total (primary plus bacterial) production during this period. The vertical and seasonal distribution of bacterial production in Little Crooked Lake was strongly influenced by the distribution of primary production. From April through September 1983, the depth of maximum bacterial production rates in the water column was related to the depth of high rates of primary production. On a seasonal basis, primary production increased steadily from May through September, and bacterial production increased from May through August and then decreased in September.
Journal Article↗
Thymidine incorporation by free-living and particle-bound bacteria in a eutrophic dimictic lake.
The percentage of [methyl-H]thymidine incorporated into samples from a dimictic eutrophic lake and retained on polycarbonate membranes of 3.0-, 1.0-, and 0.2-mum pore size was studied in a lake with filamentous cyanobacteria as the dominant phytoplankton type throughout the period of thermal stratification. Water samples were also examined by epifluorescence microscopy for evidence of algal senescence and bacterial colonization of intact and damaged cyanobacterial filaments. A small percentage (2 to 20%) of bacterial activity was retained by filters with pore sizes >/= 1 mum in epilimnetic samples. Epilimnetic samples also had a small percentage of cyanobacterial filaments, either intact or damaged, which were visibly colonized by bacteria in summer and fall samples. A significant proportion (20 to 35%) of bacterial activity was retained by filters with pore sizes >/= 1 mum in samples collected from the metalimnion and hypolimnion during late summer and fall. The proportion of damaged cyanobacterial filaments was higher in these samples than in those from the epilimnion or from those obtained early in the summer. Furthermore, the filaments in these samples were more heavily colonized by bacteria. Overall, particle-bound production accounted for only 2 to 19% of total bacterial production from April to August in all water layers. It appears that the supply of colonizable particles (damaged cyanobacterial filaments) is an important factor affecting the level of particle-bound bacterial activity in this lake.
Journal Article↗
Measurement of in situ activities of nonphotosynthetic microorganisms in aquatic and terrestrial habitats.
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Adenine↗
Is the information content of DNA evolutionarily significant?
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Animals↗
Autotrophic Growth of Gas Vacuolate Strains of Microcyclus aquaticus on Methanol and Hydrogen.
Seven strains of Microcyclus aquaticus were found to be capable of growth on methanol and hydrogen as energy sources. Carbon was incorporated as CO(2) via the Calvin cycle, as shown by the presence of ribulosebisphosphate carboxylase activity in methanol-grown cells and by the absence of key enzymes of the ribulose monophosphate and serine pathways. In addition, incoporation of [C]methanol into cells was diminished when cultures were incubated in gas atmospheres enriched with carbon dioxide.
Journal Article↗
Influence of Temperature, Oxygen, and pH on a Metalimnetic Population of Oscillatoria rubescens.
Planktonic Oscillatoria spp. often inhabit depths of thermally stratified lakes in which gradients of physical and chemical factors occur. Measurements of photosynthetic rate or photosynthetic carbon metabolism were used to evaluate the importance of vertical gradients of temperature, oxygen, and pH upon Oscillatoria rubescens in Crooked Lake, Ind. At the low light intensities experienced in situ, neither photosynthetic rate nor relative incorporation of carbon dioxide into low-molecular-weight compounds, polysaccharide, or protein was affected by temperature. At a 10-fold-higher light intensity, the photosynthetic rate increased as temperature increased; most of the additional carbon accumulated as polysaccharide. Polysaccharide which was synthesized at high light intensity and temperature was respired when the organisms were placed in the dark, but was not used for protein biosynthesis. When O. rubescens was shifted from high light to low light, a fraction of the polysaccharide was metabolized into protein. Adaptation to growth at lower temperatures by O. rubescens cultures resulted in a decrease in the maximum photosynthetic rate. Oxygen inhibited photosynthesis by only 10 to 15% at concentrations typically found in the lake. The photosynthetic rates at pH values which occurred in Crooked Lake were all near the maximum. Thus, gradients of temperature, oxygen, or pH are not likely to significantly affect the distribution of O. rubescens in Crooked Lake, given the low light intensity at which O. rubescens grows and the range of values for those factors in the lake.
Journal Article↗
Physiological Changes Within a Metalimnetic Layer of Oscillatoria rubescens.
Different depths within a metalimnetic layer of Oscillatoria rubescens were sampled, and changes in biochemical composition and photosynthetic rate were analyzed. Although differences in pigment and protein content were found, the photosynthetic rates of the samples were not significantly different.
Journal Article↗
Changes in photosynthetic rate and pigment content of blue-green algae in Lake Mendota.
Blue-green algal blooms were present in Lake Mendota (Dane County, Wis.) from June to November 1976. Concentrations of total algal biomass and of particular algal species were monitored and compared with the pigment contents (chlorophyll a and phycocyanin) and photosynthetic rate of the algal populations. The specific photosynthetic rate (micrograms of C fixed per microgram of chlorophyll a per hour) was a good measure of the physiological state of the algae because this quantity increased just before each population increase and decreased before algal densities diminished. Since the quantity of light in the epilimnion which was available for photosynthesis by algal cells decreased in summer when the high algal densities attenuated incoming radiation, we investigated the possibility that the organisms would utilize lower light intensities more efficiently by increasing their pigment contents. Although some evidence of enhanced utilization of low light levels was found in the period from July to October, this result was not due to increasing chlorophyll and phycocyanin contents. There was a decrease in the phycocyanin content of the algae during this period, perhaps related to the availability of inorganic nitrogen.
Chlorophyll↗
Effect of temperature on blue-green algae (cyanobacteria) in lake mendota.
The temperature optimum for photosynthesis of natural populations of blue-green algae (cyanobacteria) from Lake Mendota was determined during the period of June to November 1976. In the spring, when temperatures ranged from 0 to 20 degrees C, there were insignificant amounts of blue-green algae in the lake (less than 1% of the biomass). During the summer and fall, when the dominant phytoplankton was blue-green algae, the optimum temperature for photosynthesis was usually between 20 and 30 degrees C, whereas the environmental temperatures during this period ranged from 24 degrees C in August to 12 degrees C in November. In general, the optimum temperature for photosynthesis was higher than the environmental temperature. More importantly, significant photosynthesis also occurred at low temperature in these samples, which suggests that the low temperature alone is not responsible for the absence of blue-green algae in Lake Mendota during the spring. Temperature optima for growth and photosynthesis of laboratory cultures of the three dominant blue-green algae in Lake Mendota were determined. The responses of the two parameters to changes in temperature were similar; thus, photosynthesis appears to be a valid index of growth. However, there was little photosynthesis by laboratory cultures at low temperatures, in contrast to the natural samples. Evidence for an interaction between temperature and low light intensities in their effect on photosynthesis of natural samples is presented.
Journal Article↗
[Preoperative evaluation of the probability of postpericardiotomy syndrome occurrence].
36 women (43%) and 40 men (53%) (total 76) before cardiac surgery underwent the study. The average age was 50 +/- 12,62. The postpericardiotomy syndrome (PPS) was observed in 44 patients (58%). Statistically significant higher mean level CD8 lymphocytes was preoperatively stated in non-PPS patients in comparison with PPS ones (12 PPS pts-38% v.s. 4 non-PPS-9%; p < 0.01). The ratio CD4 to CD8 exceed 1.6 in group of 25 patients (57%) with PPS and only in 9 patients (28%) without PPS (p < 0.05). CD4/CD8 ratio > 1.6 and increased level of lymphocytes with transferrin receptors was more often observed in PPS patients (18 pts; 41%) in comparison with non-PPS ones (3 pts; 9%). The existence of preoperative antimyocardial antibodies did not effect on the higher risk of PPS.
Adolescent↗