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Biomedical subjects

E L Tatum

Publications and source records attributed to E L Tatum.

At least 19 recordsLinked to original sources
PubMed1989

Community patterns of posttraumatic stress disorders.

This paper reports lifetime rates for posttraumatic stress disorder (PTSD) in two rural northwest communities. One community was affected by a major natural disaster, the eruption of Mt. St. Helens. Following an epidemiology study of this disaster, community-wide patterns of PTSD were identified. Disaster-related, combat, sexual assault, and all other types of PTSD are presented for men and women. Symptom patterns from these distinct PTSD stressors are compared along with concurrent psychiatric disorders. The findings are discussed with other studies that use a broader definition of disaster stress response syndromes. This comparison identifies a limitation of PTSD diagnostic criteria that may significantly underestimate community rates.

Adult↗
PubMed1986

Psychiatric reactions to disaster: the Mount St. Helens experience.

Following the 1980 Mount St. Helens volcanic eruption, psychiatric reactions were studied in the disaster area and in a control community. Using the new criterion-based diagnostic method for psychiatric epidemiologic research, the Diagnostic Interview Schedule, the authors found a significant prevalence of disaster-related psychiatric disorders. These Mount St. Helens disorders included depression, generalized anxiety, and posttraumatic stress reaction. There was a progressive "dose-response" relationship in the comparison of control, low-exposure, and high-exposure groups. The dose-response pattern occurred among both the bereaved and the property-loss victims.

Adolescent↗
PubMed1986

Evaluation of mental effects of disaster, Mount St. Helens eruption.

This psychiatric epidemiology study following the Mount St. Helens volcanic disaster revealed a significant morbidity for psychiatric disorders. The increased prevalence showed a dose response pattern in three population groups. The findings are reported as relative and attributable risk for the two exposed populations as compared to a control group. Patterns of significant risk are presented for sex, age, and for victims with pre-existing physical illness. The research utilized a new criteria-based interview schedule for the identification of psychiatric disorders. The methodology is reviewed in the context of the controversies and assumptions within the field of behavioral response to disaster stress. There are important implications for public health planning and intervention.

Adult↗
PubMed1980

Characterization and regulation of galactose transport in Neurospora crassa.

Two galactose uptake systems were found in the mycelia of Neurospora crassa. In glucose-grown mycelia, galactose was transported by a low-affinity (Km = 400 mM) constitutive system which was distinct from the previously described glucose transport system I (R. P. Schneider and W. R. Wiley, J. Bacteriol. 106:479--486, 1971). In carbon-starved mycelia or mycelia incubated with galactose, a second galactose transport activity appeared which required energy, had a high affinity for galactose (Km = 0.7 mM), and was shown to be the same as glucose transport system II. System II also transported mannose, 2-deoxyglucose, xylose, and talose and is therefore a general monosaccharide transport system. System II was derepressed by carbon starvation, completely repressed by glucose, mannose, and 2-deoxyglucose, and partially repressed by fructose and xylose. Incubation with galactose yielded twice as much activity as starvation. This extra induction by galactose required protein synthesis, and represented an increase in activity of system II rather than the induction of another transport system. Glucose, mannose, and 2-deoxyglucose caused rapid degradation of preexisting system II; fructose and xylose caused a slower degradation of activity.

Biological Transport, Active↗
PubMed1980

Fructose transport in Neurospora crassa.

A specific fructose uptake system (Km = 0.4 mM) appeared in Neurospora crassa when glucose-grown mycelia were starved. Fructose uptake had kinetics different from those of intramycelial fructose phosphorylation, and uptake appeared to be carrier mediated. The only sugar which competitively inhibited fructose uptake was L-sorbose (Ki = 9 mM). Glucose, 2-deoxyglucose, mannose, and 3-O-methyl glucose were noncompetitive inhibitors of fructose uptake. Incubation of glucose-grown mycelia with glucose, 2-deoxyglucose, or mannose prevented derepression of the fructose transport system, whereas incubation with 3-O-methyl glucose caused the appearance of five times as much fructose uptake activity as did starvation conditions.

Biological Transport, Active↗
PubMed1976

Differential inhibition of branching enzyme in a morphological mutant and in wild type Neurospora. Influence of carbon source in the growth medium.

1. A morphological mutant of Neurospora crassa, smco 9, (R2508) that exhibits colonial morphology when grown on sucrose or on maltose, showed a partial reversal of this morphology toward that of the wild type when it was grown on potato starch or on isomaltose. 2. A common feature of both potato starch and isomaltose is the presence of alpha-1, 6 glucosidic linkages. This suggested that these morphological effects might be due to differences in alpha-1,4 glucan: alpha-1,4 glucan 6 glycosyltransferase, (EC 2.4.1.18) commonly known as "the branching enzyme". 3. The branching enzyme was purified from wild type, Neurospora crassa, and from the semicolonial mutant, R2508, both grown on sucrose or on potato starch. It has a molecular weight of 140,000 as estimated by gel filtration on a Bio Gel A 1.5 m column. This enzyme plus phosphorylase a in an unprimed reaction catalyzes the synthesis of a branched polysaccharide in vitro. 4. No branching enzyme activity was apparent in extracts of the mutant R2508, grown on potato starch until a thermolabile inhibitor was removed by fractionation on a DEAE column. 5. This inhibitor has a molecular weight greater than 100,000 as estimated on a P-100 polyacrylamide gel column. The specificity of the inhibitor is not absolute in that it inhibits glycogen synthetase in addition to the branching enzyme in Neurospora.

Cell Division↗
PubMed1975

Induction by RNA of inositol independence in Neurospora crassa.

The effect of purified wild-type RNA (allo-RNA) on genetic reversion of inositol-requiring mutant 89601 of Neurospora crassa is described. The mutant (inos minus) strain, on treatment with the wild-type RNA preparation, was found to revert to wild type (inos+) in significant numbers. RNA from the mutant (iso-RNA) and allo-RNA digested by RNase were ineffective in causing genetic reversion at the inositol locus. The allo-RNA-induced revertants were stable and showed a Mendelian transmission of the inos+ character.

Inositol↗
PubMed1973

Non-Mendelian inheritance of DNA-induced inositol independence in Neurospora.

Inositol-independent (inos(+)) revertants of Neurospora induced in inositol-requiring mutants by treatment with wild-type DNA in previous studies were found to be stable and to grow well in the absence of inositol. Genetic data presented in this paper show that a major proportion of these induced revertants rarely transmitted the inositol independence character (inos(+)) to their sexual progeny. Non-Mendelian transmission of the transformed character (inos(+)) was also found to occur in some of the sexual progeny in subsequent generations. These genetic data support the idea that the transforming DNA pieces carrying the genetic information (called exosomes) are not readily integrated into the host genome. It is suggested that elimination of most exosomes during meiosis causes a loss of the genetic information and leads to non-Mendelian transmission of the induced revertant character (inos(+)).

Crosses, Genetic↗
PubMed1972

Fusion of mammalian somatic cells by microsurgery.

Mammalian somatic-cell hybrids can be formed in a direct and precise manner by microsurgery. Fusion of cells brought about in this way permits selection of specific, identifiable cells of the same or different types or species and their fusion at telophase.

Animals↗
PubMed1972

Effect of L-sorbose on polysaccharide synthetases of Neurospora crassa (glycogen- -1,3-glucan-morphology-cell wall-digitonin-particulate enzymes).

Neurospora glycogen synthetase (EC 2.4.1.11) occurs in 100,000 x g particles. The two forms (glucose-6-phosphate dependent-independent) of glycogen synthetase were solubilized and separated by digitonin treatment of the 100,000 x g particles. Glucan synthetase activity of Neurospora was found only in a cell-wall preparation. These two enzymes have been characterized in relation to the paramorphogenic action of sorbose. Sorbose-grown cultures showed a marked decrease in the specific activity of both enzymes, as compared to sucrose-grown wild-type cultures. Sorbose inhibited the activity of the wild-type enzymes both in vivo and in vitro. In the presence of 5 mM sorbose incorporation of [(14)C]glucose from [(14)C]uridinediphosphate glucose into glycogen by the dependent form of glycogen synthetase was completely inhibited. Thus, the paramorphogenic action of sorbose seems to result from its inhibition of these enzymes of cell-wall biosynthesis. Activities of the enzymes from the sorbose-resistant mutant, patch, were not affected by sorbose either in vivo or in vitro.

Carbon Isotopes↗
PubMed1970

Glucose-6-phosphate dehydrogenase and Neurospora morphology.

In addition to the Neurospora crassa mutant col-2, mutations in two other unlinked genes, balloon and frost, lead to distinct morphological growth and abnormal glucose-6-phosphate dehydrogenases. The glucose-6-phosphate dehydrogenases from these strains have increased thermolabilities, altered kinetic parameters, and distinctive electrofocusing patterns. The altered enzyme segregates with each morphological phenotype in crosses to wild type, and there is a correlation between the severity of the enzymic defect and the degree of morphological abnormality in heterocaryons and double mutants. These results are compatible with the hypotheses that the balloon, frost, and col-2 genes are structural genes for glucose-6-phosphate dehydrogenase and that the pleiotropic effects of these altered dehydrogenases are responsible for the mutant morphologies.

Genetics, Microbial↗
PubMed1970

Phosphoglucomutase mutants of Neurospora sitophila and their relation to morphology.

Biochemical and genetic evidence is presented that the rg-1 and rg-2 genes control the structure of the two isozymes of phosphoglucomutase (Phosphoglucomutase I and II) in Neurospora silophila. Results of kinetic and gel filtration studies show that the two phosphoglucomutases may exist in vitro either as separate or as a single but complex molecular species depending on the ionic concentration. The complex phosphoglucomutase molecule is suggested to be the physiologically active form of the enzyme. The change in the enzyme structure is discussed in relation to the morphological change in the ragged mutant strains.

Chromatography, DEAE-Cellulose↗