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A Aronson

Publications and source records attributed to A Aronson.

At least 19 recordsLinked to original sources
PubMed2002

Sporulation and delta-endotoxin synthesis by Bacillus thuringiensis.

Bacillus thuringiensis is distinguished from the very closely related Bacillus cereus and Bacillus anthracis by the presence of several plasmid-encoded delta-endotoxin genes. These delta-endotoxins, synthesized as protoxins, are produced in large quantities during sporulation and are packaged into intracellular inclusions. Ingestion of the inclusions by insect larvae leads to protoxin solubilization and conversion to toxins each specific for one of several orders of insects. The toxins form cation-selective channels in the membrane of cells lining the larval midgut with subsequent lethality. In most cases, delta-endotoxin synthesis and sporulation are closely coupled. The latter process in B. thuringiensis is probably virtually identical to that in Bacillus subtilis with the additional use of mother cell sporulation forms of RNA polymerase for the synthesis of the delta-endotoxins. There are other more subtle plasmid-encoded functions or plasmid interactions related to regulating protoxin synthesis. Consideration of both plasmid and chromosomal genes is thus critical for defining this organism.

Bacillus thuringiensis↗
PubMed2001

Regulation of the packaging of Bacillus thuringiensis delta-endotoxins into inclusions.

During sporulation, many Bacillus thuringiensis subspecies synthesize several related delta-endotoxins which are packaged into bipyramidal intracellular inclusions. These inclusions are solubilized in the alkaline, reducing conditions of the midguts of susceptible insect larvae and are converted by proteolysis to active toxins. The toxins insert into the membranes of cells lining the midgut and form cation-selective channels, which results in lethality. There are three delta-endotoxins, Cry1Ab3, Cry1Ca1, and Cry1Da1, present in the inclusions produced by a B. thuringiensis subsp. aizawai cell. While the ratio of the steady-state mRNAs for these three protoxins has been shown to differ (cry1Ab3/cry1Ca1/cry1Da1 mRNA ratio, 4:2:1), the half-lives of the cry1Da1 and cry1Ab3 mRNAs were found to be similar, indicating that there were differences in the transcription rates. The relative contents of these delta-endotoxins in purified inclusions from B. thuringiensis subsp. aizawai have been measured previously, and an even greater relative deficiency of the Cry1Da1 protoxin (ratio, 20:12:1) was found. In order to account for this deficiency, other steps which could be involved in inclusion formation, such as translation and packaging, were examined. The three cry genes have the same dual overlapping promoters, but the ribosome binding sequence for the cry1Da1 gene was not the consensus sequence. Translation was enhanced about fourfold by changing to the consensus sequence. In addition, the relative amount of Cry1Da1 protoxin in inclusions was twofold lower when cells were sporulated in Luria-Bertani (LB) medium than when cells were sporulated in a glucose-yeast extract medium. This difference was attributable to packaging since the relative amounts of Cry1Da1 antigen in cells sporulating in the two media were the same. Some factor(s) required for packaging of the Cry1Da1 protoxin in inclusions is apparently limiting in LB medium. Differences in the initial transcription rates, translation efficiencies, and packaging all contribute to the delta-endotoxin composition of an inclusion.

Amino Acid Sequence↗
PubMed2001

How treating psychoanalysts respond to psychotherapy research constraints.

The psychoanalytic community increasingly recognizes the importance of research on psychoanalytic treatments, yet a significant number of psychoanalysts continue to believe that research is either irrelevant to psychoanalysis or impossible to accomplish. Psychoanalysts who accept the value of research express concern that intrusions required by research protocols create significant distortions in the psychoanalytic process. The authors, all psychoanalysts, are studying the outcome of a brief (twenty-four-session) psychodynamic treatment of panic disorder. They report their experiences and struggles with the intrusions of videotaping, working with a treatment manual, and time-limited treatment. This research process required them to question old beliefs and to confront feelings of disloyalty toward their analytic training and identity, particularly with regard to keeping a "clean field" and routinely performing long-term analysis of character. The therapists' psychoanalytic knowledge, however, emerged as crucial for them in managing specific research constraints. Despite concerns about providing inadequate treatment, therapists were found to engage patients with psychoanalytic tools and focus in vibrant and productive therapies that led to significant improvements in panic symptoms and associated quality of life. The authors suggest that psychoanalysts have been overestimating the potential damage of research constraints on psychoanalytic process and outcome.

Adult↗
PubMed2001

A pilot open trial of brief psychodynamic psychotherapy for panic disorder.

This is a complete report of an open trial of manualized psychodynamic psychotherapy for treatment of panic disorder, Panic-Focused Psychodynamic Psychotherapy (PFPP). Twenty-one patients with PD were entered into a trial of twice-weekly, 24-session treatment. Sixteen of 21 experienced remission of panic and agoraphobia. Treatment completers with depression also experienced remission of depression. Improvements in symptoms and in quality of life were substantial and consistent across all measured areas. Symptomatic gains were maintained over 6 months. This report was prepared specifically to describe 6-month follow-up on these patients. Psychodynamic psychotherapy appears to be a promising nonpharmacological treatment for panic disorder.

Adult↗
PubMed2000

Incorporation of protease K into larval insect membrane vesicles does not result in disruption of integrity or function of the pore-forming Bacillus thuringiensis delta-endotoxin.

Bacillus thuringiensis delta-endotoxins insert into the brush border membranes of insect larval cells to form ion channels. A possible interaction of these toxins with a cytoplasmic component was examined by preloading vesicles from insect larval cells with protease K followed by incubation with toxin. There was no evidence for toxin antigens smaller than the intact toxin in extracts of solubilized vesicles, nor was there an effect of the inclusion of protease K on either of two functional properties, the formation of toxin aggregates or of ion pores. These toxins, physically and functionally, appear to be confined to the membrane.

Animals↗
PubMed2000

Regulation by overlapping promoters of the rate of synthesis and deposition into crystalline inclusions of Bacillus thuringiensis delta-endotoxins.

During sporulation, Bacillus thuringiensis produces intracellular, crystalline inclusions comprised of a mixture of protoxins active on insect larvae. A major class of these protoxin genes, designated cry1, is transcribed from two overlapping promoters (BtI and BtII) utilizing RNA polymerase containing sporulation sigma factors sigma(E) and sigma(K), respectively. Fusions of these promoters to lacZ were constructed in order to analyze transcription patterns. Mutations within the -10 region of the BtII promoter (within the spacer region of the BtI promoter) which departed from the consensus -10 sequence for either sigma(E) or sigma(K) resulted in inactivation of transcription from BtII and a fivefold stimulation of transcription from BtI. In contrast, transcription from both promoters was inhibited with a change to the sigma(E) consensus. One of the "promoter-up" mutations was fused to the cry1Ac1 gene, and enhanced transcription was confirmed by Northern blotting. There was an increase in the accumulation of Cry1Ac antigen at early but not later times in sporulation in the mutant. This shift was due to the rapid turnover of much of the excessively accumulated protoxin at the early times as measured by pulse-chase labeling. As a result of the turnover and the inactivation of the BtII promoter, the mutant produced smaller inclusions which contained two- to threefold-less protoxin than inclusions from the wild type. Promoter overlap is a mechanism for modulating protoxin synthesis, thus ensuring the efficient packaging of these protoxins into inclusions.

Bacillus thuringiensis↗
PubMed2000

Open trial of psychodynamic psychotherapy for panic disorder: a pilot study.

OBJECTIVE: This report contains preliminary data from an open trial of brief psychodynamic psychotherapy for panic disorder. METHOD: Fourteen patients with primary DSM-IV panic disorder completed a 24-session, twice-weekly course of psychodynamic psychotherapy. Other psychiatric treatment was not permitted throughout the 12-week treatment period and the 6-month follow-up. Symptoms were assessed at baseline, treatment termination, and 6-month posttermination follow-up (40 weeks). RESULTS: Statistically significant, clinically meaningful improvements appeared in panic, depression, anxiety, and functional impairment both at treatment termination and at 6-month follow-up. CONCLUSIONS: Psychodynamic monotherapy can be used successfully to retain and treat patients with panic disorder. Psychodynamic interventions warrant further study for patients with panic disorder.

Adult↗
PubMed1999

Specific binding of the E2 subunit of pyruvate dehydrogenase to the upstream region of Bacillus thuringiensis protoxin genes.

During sporulation, Bacillus thuringiensis produces inclusions comprised of different amounts of several related protoxins, each with a unique specificity profile for insect larvae. A major class of these genes designated cry1 have virtually identical dual overlapping promoters, but the upstream sequences differ. A gel retardation assay was used to purify a potential regulatory protein which bound with different affinities to these sequences in three cry1 genes. It was identified as the E2 subunit of pyruvate dehydrogenase. There was specific competition for binding by homologous gene sequences but not by pUC nor Bacillus subtilis DNA; calf thymus DNA competed at higher concentrations. The B. thuringiensis gene encoding E2 was cloned, and the purified glutathione S-transferase-E2 fusion protein footprinted to a consensus binding sequence within an inverted repeat and to a potential bend region, both sites 200-300 base pairs upstream of the promoters. Mutations of these sites in the cry1A gene resulted in decreased binding of the E2 protein and altered kinetics of expression of a fusion of this regulatory region with the lacZ gene. Recruitment of the E2 subunit as a transcription factor could couple the change in post exponential catabolism to the initiation of protoxin synthesis.

Amino Acid Sequence↗
PubMed1999

Subspecies-dependent regulation of Bacillus thuringiensis protoxin genes.

Bacillus thuringiensis accumulates, primarily during sporulation, large quantities of insecticidal protoxins which are deposited as crystalline, intracellular inclusions. Most subspecies contain several plasmid-encoded cry genes, each of which has a unique specificity. The overall toxicity profile of a subspecies depends not only on the array of cry genes present but also on the relative expression of the genes. In general, transcription depends on sporulation-specific sigma factors, but little is known about regulation of expression of the individual genes. In order to determine whether expression of a particular cry gene varies in different subspecies, lacZ fusions to the cry promoters of two protoxin genes (cry1 class) were constructed. Protoxin accumulation and mRNA contents were also measured by performing immunoblotting and Northern analyses, respectively. The expression of a cry1Ab-lacZ fusion, but not the expression of a cry1C-lacZ fusion, was three to four times lower in B. thuringiensis subsp. aizawai strains than in B. thuringiensis subsp. kurstaki or B. thuringiensis subsp. tolworthi. Also, the Cry1Ab antigen and steady-state mRNA contents of B. thuringiensis subsp. aizawai were lower. The regulation of the genes must involve regions upstream of the promoters which are unique to each cry gene since (i) mutations in the upstream region of the cry1Ab gene resulted in enhanced expression in B. thuringiensis subsp. aizawai and (ii) no differences were found when the lacZ fusions contained the cry1Ab promoters but no upstream sequences. The capacity to regulate each of the protoxin genes must be a factor in the overall protoxin composition of a subspecies and thus its toxicity profile.

Antigens, Bacterial↗
PubMed1999

Oedipal dynamics in panic disorder.

Both research and clinical work have revealed factors that can lead to the onset and persistence of panic disorder. Preoedipal conflicts intensify the danger of oedipal longings for panic patients. Competition with the same-sex parent is linked with angry preoedipal fantasies and associated fears of disruption in attachments. Fantasies or actual successes can thus trigger panic episodes. Regression to a helpless, dependent state such as panic defends against the danger of aggressive, competitive fantasies and actual achievements. However, the regressive state can also be experienced as dangerous, and can be linked with frightening homosexual fantasies. A reactive aggressive oedipal stance can sometimes result, triggering escalating turmoil. The panic episode serves a series of compromise formations in dealing with these conflicted wishes.

Adult↗
PubMed1996

The factor structure of schizotypal symptoms in a clinical population.

There is some support for the hypothesis that the factor structure of schizophrenia symptoms is similar to the factor structure of schizotypal symptoms in nonschizophrenia populations. However, no studies to date have examined schizotypal symptoms in patients with personality disorders. In this study, confirmatory factor analyses were conducted to test the relative fit of several models of the factorial structure of schizotypal symptoms in patients diagnosed with personality disorders. The EQS: Structural Equations Program was used to analyze DSM-III symptoms of schizotypal personality disorder (SPD) based on structured clinical interviews with 213 patients meeting a diagnosis for at least one personality disorder. A subgroup of the total sample was also evaluated for DSM-III-R criteria (n = 143) to test competing models of the DSM-III-R symptoms of SPD. A three-factor model consisting of a cognitive-perceptual, interpersonal, and paranoid factor yielded the best fit to the data relative to the other models tested. These results suggest that the three-factor model of schizophrenia symptoms may not entirely correspond to the factors underlying milder schizotypal symptoms expressed in a clinical population. It is suggested that future research focus on both the similarities and the differences between SPD and schizophrenia.

Adult↗
PubMed1995

Cognitive function and biological correlates of cognitive performance in schizotypal personality disorder.

There is evidence that some schizophrenic patients have deficits on tests of cognitive function, particularly tests of executive function, including the Wisconsin Card Sorting Test (WCST) and the Trail-making Test, Part B. This study was conducted to determine the generalizability of these findings across the schizophrenia spectrum to schizotypal personality disorder (SPD). Forty DSM-III SPD patients, 56 nonschizophrenia-related other personality disorder (OPD) patients, and 32 normal volunteers from two medical centers performed tests of executive function such as the WCST, Trail-making Part B, Stroop Word-Color Test, and Verbal Fluency, as well as tests of more general intellectual functioning such as the Wechsler Intelligence Scale-Revised Vocabulary and Block Design subtests, and Trail-making Part A. SPD patients performed more poorly on the WCST and on Trail-making Part B than did OPD patients or normal subjects; the groups did not differ on tests of general intellectual functioning. SPD patients may share some of the cognitive deficits observed in schizophrenia.

Adult↗
PubMed1995

The protoxin composition of Bacillus thuringiensis insecticidal inclusions affects solubility and toxicity.

Most Bacillus thuringiensis strains producing toxins active on lepidoptera contain several plasmid-encoded delta-endotoxin genes and package related protoxins into a single inclusion. It was previously found that in B. thuringiensis subsp. aizawai HD133, which produces an inclusion comprising the CryIAb, CryIC, and CryID protoxins, there is a spontaneous loss in about 1% of the cells of a 45-mDa plasmid containing the cryIAb gene. As a result, inclusions produced by the cured strain were less readily solubilized at pH 9.2 or 9.5 and had a decreased toxicity for Plodia interpunctella, despite the presence of the CryIC protoxin, which was active when solubilized. These results suggested that protoxin composition was a factor in inclusion solubility and toxicity and that the cryIAb gene, which is also present on an unstable plasmid in several other subspecies, may have a unique role in inclusion solubility and toxicity. Introduction of a cloned copy of this gene into the plasmid-cured derivative of B. thuringiensis subsp. aizawai HD133 resulted in an increase in the solubility at pH 9.2 of all of the inclusion proteins from less than 20% to greater than 45% and a lowering of the 50% lethal concentration (LC50, in micrograms [dry weight] per square centimeter) of inclusions for Spodoptera frugiperda from 35 to 10. These values are the same as those found with inclusions from B. thuringiensis subsp. aizawai HD133, and in all cases, the LC50 of the solubilized protoxins was 10. Transformants containing related cryIA genes produced inclusions which were more than 95% solubilized at pH 9.2 but also had LC50 of 10.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A Bacillus subtilis bglA gene encoding phospho-beta-glucosidase is inducible and closely linked to a NADH dehydrogenase-encoding gene.

A 2.7-kb HindIII fragment from Bacillus subtilis contains an open reading frame (ORF) encoding a protein with homology to an Escherichia coli phospho-beta-glucosidase B (PBG B). The B. subtilis gene was induced by aromatic beta-glucosides, as judged by Northern hybridization and could complement an E. coli bglB mutant. Immediately down-stream from this B. subtilis bglA gene, there was a partial ORF on the opposite strand which encoded a polypeptide with extensive homology to NADH dehydrogenase from an alkalophilic Bacillus. These genes were mapped to 340 degrees between hut and gnt on the B. subtilis chromosome. Disruption of these genes by insertion of a neomycin-resistance-encoding gene (neo) did not result in any phenotypic changes comparable to those found in E. coli mutants.

Amino Acid Sequence↗
PubMed1988

Epidemiology of focal and generalized dystonia in Rochester, Minnesota.

The epidemiology of generalized and focal dystonias was investigated in the Rochester, Minnesota, population over the period 1950-1982. The crude incidence of generalized dystonia was 2 per million persons per year, and for all focal dystonias combined, 24 per million per year. The crude prevalence rate was 34 per million persons for generalized dystonia and 295 per million persons for all focal dystonias. Torticollis was the most common focal dystonia; essential blepharospasm, oromandibular dystonia, spasmodic dysphonia, and writer's cramp were less common and had roughly equal incidence and prevalence rates.

Adolescent↗
PubMed1988

Postpsychotic depression and negative symptoms: an investigation of syndromal overlap.

The authors studied 46 patients with the operationally defined syndrome of postpsychotic depression following episodes of schizophrenia or schizoaffective disorder. Half of these patients were also found to satisfy criteria for negative symptoms. The patients with negative symptoms were rated as more severely ill on global measures, but there was only limited evidence that they were more depressed. Nevertheless, in a randomized double-blind trial of imipramine versus placebo as an adjunct to the fluphenazine decanoate and benztropine regimens of the patients with negative symptoms, the patients who received imipramine seemed to show more improvement.

Adolescent↗