The bldB gene encodes a small protein required for morphogenesis, antibiotic production, and catabolite control in Streptomyces coelicolor.

Mutants blocked at the earliest stage of morphological development in Streptomyces species are called bld mutants. These mutants are pleiotropically defective in the initiation of development, the ability to produce antibiotics, the ability to regulate carbon utilization, and the ability to send and/or respond to extracellular signals. Here we report the identification and partial characterization of a 99-amino-acid open reading frame (ORF99) that is capable of restoring morphogenesis, antibiotic production, and catabolite control to all of the bldB mutants. Of the existing bld mutants, bldB is of special interest because the phenotype of this mutant is the most pleiotropic. DNA sequence analysis of ORF99 from each of the existing bldB mutants identified base changes either within the coding region of the predicted protein or in the regulatory region of the gene. Primer extension analysis identified an apparent transcription start site. A promoter fusion to the xylE reporter gene showed that expression of bldB is apparently temporally regulated and that the bldB gene product is involved in the regulation of its own expression.

The bld mutants of Streptomyces coelicolor are defective in the regulation of carbon utilization, morphogenesis and cell--cell signalling.

Mutants of Streptomyces coelicolor blocked at the earliest visible stage of morphological differentiation are called bld mutants. These mutants fail to form aerial hyphae on rich medium and most are defective in antibiotic production. One striking feature of these mutants is that, with the exception of bldB, their morphological defect is carbon-source dependent. In our investigation of catabolite control in Streptomyces, we identified mutants that were resistant to glucose repression and were also bld. The existence of these new bld mutants led us to examine the catabolite control phenotype of the previously described bld mutants which were not known to contain defects in carbon regulation. We report here that all of the characterized bld mutants of S. coelicolor are defective in the regulation of galP1, and that at least one of the bld mutants, bldB, is globally deregulated for carbon utilization. Complementation of the morphological defect of bldA and bldB mutants with a cloned copy of the wild-type bld gene simultaneously restored normal regulation of galP1, indicating that both aspects of the mutant phenotype are caused by the same lesion. We suggest a new interpretation for the role of the bld genes in development in Streptomyces. We suggest that the primary defect in bld mutants is in the regulation of carbon utilization, not specifically in the activation of genes whose products regulate the development pathway as previously suggested. We speculate that the inability of bld mutants to initiate morphogenesis is a secondary consequence of their inability to sense and/or signal starvation.

The effects of stress, mood, and coping on blood glucose in NIDDM: a prospective pilot evaluation.

Eight subjects (Ss) with non-insulin-dependent diabetes (NIDDM) monitored their stress, blood glucose (BG), food intake, activity (via pedometer), mood, and coping responses for 8 days. They alternated 2 daily, self-selected ADA food-exchange diets to control for the effects of stress on adherence to diet. BG was significantly higher on high-stress compared to low-stress days. This effect was at least partially mediated by the effect of stress on activity; Ss were significantly less active on high-stress days. Further analyses suggested idiosyncratic relationships between mood and BG, and some evidence was found to suggest a relation between stress, coping, and BG.

Cortisol excretion in high and low cynically hostile men.

Cynical hostility as measured by the Cook and Medley Hostility (Ho) Scale has been found in some studies to be associated with increased risk of life-threatening illness. Previous laboratory studies of cardiovascular reactivity have been consistent with the general hypothesis that increased physiological responsiveness is one possible mechanism underlying the association between hostility and health. The present study extended this previous research by evaluating urinary cortisol excretion during routine daily activities in a sample of high and low cynically hostile young men. Although high and low Ho groups did not differ in their cortisol excretion upon awakening, the high Ho group displayed more than twice the increase in cortisol excretion during daytime hours as that occurring among low hostile men. This difference dissipated during the evening hours. Results are discussed in terms of possible physiological mechanisms linking hostility and health.

Cognitive, behavioral, and affective correlates of the Cook and Medley Hostility Scale.

The Cook and Medley Hostility (Ho) Scale is an increasingly important measure in studies examining health consequences of hostility. The two studies discussed herein provide further evidence of the construct validity of this measure. In Study 1, high Ho scores were associated with a greater level of aroused anger and disparaging appraisals of subjects' partners in a competitive reaction-time game as well as marginally more frequent antagonistic behavior. In Study 2, high Ho scores were associated with greater levels of angry and suspicious thoughts and feelings in response to hypothetical interpersonal conflicts and the tendency to attribute hostile intent to actors' displays of negative social behaviors. These findings are consistent with previous conceptual descriptions of the cognitive, behavioral, and affective correlates of hostility. The results are discussed in terms of interpretation of studies using the Ho scale and possible refinements of the measure.

Optimism, neuroticism, coping, and symptom reports: an alternative interpretation of the Life Orientation Test.

Found in two studies that the Life Orientation Test (LOT) had limited discriminant validity relative to measures of neuroticism. Furthermore, although previous correlations of the LOT with measures of symptom reports and coping behaviors were replicated, these correlations were eliminated when neuroticism was controlled. In contrast, the correlations of symptoms and coping with neuroticism remained significant when LOT scores were controlled. Thus, the LOT is virtually indistinguishable from measures of neuroticism, and previously reported findings using this scale are perhaps more parsimoniously interpreted as reflecting neuroticism rather than optimism. These findings are discussed in terms of existing support for models of optimism and self-control and general methodological issues in studies of personality and health.