Sites within gene lacZ of Escherichia coli for formation of active hybrid beta-galactosidase molecules.

We describe the genetic analysis of 21 Escherichia coli strains in which the amino-terminal sequence of beta-galactosidase has been removed and replaced by an amino-terminal sequence from one or another of the proteins involved in maltose transport. Genetic mapping of the lacZ end of these fused genes indicates that only those fusions in which fewer than 41 amino acids are removed from the amino-terminal sequence of beta-galactosidase result in enzymatically active molecules. Within the region between amino acid 17 and amino acid 41 there are at least four or five sites where enzymatically active hybrid proteins can be formed.     

Analysis of the regulation of Escherichia coli alkaline phosphatase synthesis using deletions and φ80 transducing phages

φ80 transducing phages for the proC², phoA and phoB genes of Escherichia coli have been obtained. Two mutants have been isolated, in which the brnQ, phoA, proC, phoB (and possibly phoR) genes have been deleted. Derivatives of a phoA, phoB deletion strain which are lysogenic for a φ80phoA transducing phage make only very low levels of alkaline phosphatase activity. These results are in agreement with a positive control mechanism for the regulation of alkaline phosphatase synthesis.     

Monocyte receptors for the Fc portion of IgG increase in number in autoimmune hemolytic anemia and other hemolytic states and are decreased by glucocorticoid therapy

Peripheral blood monocyte receptors for the Fc portion of IgG were quantitatively studied in 43 normal subjects, in 14 patients with warm antibody autoimmune hemolysis (AIHA), and in nine individuals with nonantibody-mediated hemolysis. Monocytes of normal females expressed significantly greater numbers of Fc gamma receptors than did similar cells from male subjects, with no difference in affinity for the IgG1 probe. Monocyte Fc gamma receptor number was increased in patients of both sexes with AIHA; a similar, but smaller, increase in monocyte Fc gamma receptor number was noted in patients with nonantibody-mediated hemolysis. Glucocorticoid administration was associated with a dose-dependent decrease in monocyte Fc gamma receptor number in normal volunteers and patients. Possible etiologic mechanisms and pathogenetic consequences of enhanced monocyte Fc gamma binding in AIHA are discussed.     

Transferrin and Iron in Normal, Alzheimer's Disease, and Parkinson's Disease Brain Regions

Abstract: Oxidant-mediated damage is suspected to be involved in the pathogenesis of several neurodegenerative disorders. Iron promotes conversion of hydrogen peroxide to hydroxyl radical and, thus, may contribute to oxidant stress. We measured iron and its transport protein transferrin in caudate, putamen, globus pallidus, substantia nigra, and frontal cortex of subjects with Alzheimer's disease (n = 14) and Parkinson's disease (n = 14), and in younger adult (n = 8) and elderly (n = 8) normal controls. Although there were no differences between control groups with regard to concentrations of iron and transferrin, iron was significantly increased ( p < 0.05) in Alzheimer's disease globus pallidus and frontal cortex and Parkinson's disease globus pallidus, and transferrin was significantly increased in Alzheimer's disease frontal cortex, compared with elderly controls. The transferrin/iron ratio, a measure of iron mobilization capacity, was decreased in globus pallidus and caudate in both disorders. Regional transferrin and iron concentrations were generally more highly correlated (Pearson's correlation coefficient) in elderly controls than in Alzheimer's and Parkinson's disease. The altered relationship between iron and transferrin provides further evidence that a disturbance in iron metabolism may be involved in both disorders.     

Response to disodium cromoglycate in children with chronic asthma

Twenty-three children with chronic severe perennial asthma received randomly-allocated disodium cromoglycate or placebo four times a day for 12 weeks, and the alternative regimen for the subsequent 12 weeks. More than half the patients improved while on DSCG according to clinical assessment. There was a significant increase in the mean FEV_{0·75 second} during the drug period, largely owing to dramatic improvement in nine patients. No reduction in the mean decrease of FEV after exercise was demonstrated. Response, when it occurred, was evident within four weeks. The effect of the medication was consistent in individual patients throughout the 12-week period. No evidence of toxicity was discovered during the period of study.     

Genetic and Environmental Contributions to Phenotypic Components of Metabolic Syndrome: A Population‐based Twin Study

The increasing prevalence of metabolic syndrome (MS) poses a serious public‐health problem worldwide. Effective prevention and intervention require improved understanding of the factors that contribute to MS. We analyzed data on a large twin cohort to estimate genetic and environmental contributions to MS and to major MS components and their intercorrelations: waist circumference (WC), systolic (SBP) and diastolic blood pressure (DBP), fasting plasma glucose (FPG), triglycerides (TGs), and high‐density lipoprotein–cholesterol (HDL‐C). We applied structural equation modeling to determine genetic and environmental structure of MS and its major components, using 1,617 adult female twin pairs recruited from rural China. The heritability estimate for MS was 0.42 (95% confidence interval (CI): 0.00–0.83) in this sample with low MS prevalence (4.4%). For MS components, heritability estimates were statistically significant and ranged from 0.13 to 0.64 highest for WC, followed by TG, SBP, DBP, HDL‐C, and FPG. HDL‐C was mainly influenced by common environmental factors (0.62, 95% CI: 0.58–0.62), whereas the other five MS components were largely influenced by unique environmental factors (0.32–0.44). Bivariate Cholesky decomposition analysis indicated that the clinical clustering of MS components may be explained by shared genetic and/or environmental factors. Our study underscores the importance of examining MS components as intercorrelated traits, and to carefully consider environmental and genetic factors in studying MS etiology.     

Obesity is associated with reduced white matter integrity in otherwise healthy adults

Existing work demonstrates that obesity is independently associated with cognitive dysfunction and macrostructural brain changes; however, little is known about the association between obesity and white matter (WM) integrity. We explore this relationship in a large cohort of otherwise healthy subjects. The present study classified 103 adult participants from the Brain Resource International Database between 21 and 86 years of age without history of neurological, medical, or psychiatric illness according to BMI (normal weight, overweight, obese) and subjected them to diffusion tensor imaging (DTI). Resulting fractional anisotropy (FA) indexes for the corpus callosum and fornix were examined in relation to BMI and age in a multiple regression framework. Results indicated that increasing BMI was independently associated with lower FA in the genu, splenium, and fornix, and a BMI × age interaction emerged for FA in the splenium and body of the corpus callosum. When categorized, obese persons demonstrated lower FA than normal and overweight persons for all WM indexes, but no FA differences emerged between overweight and normal persons. Results indicate both a direct association between obesity and reduced WM tract integrity and an interaction between obesity and aging processes on certain WM tracts in otherwise healthy adults. While such findings suggest a possible role for adiposity in WM dysfunction and associated cognitive deficits, prospective studies are needed to clarify the nature of these relationships and elucidate underlying mechanisms.     

A novel triple fusion reporter system for use in gene trap mutagenesis

Gene trapping is an insertional mutagenesis strategy that allows for simultaneous gene identification and mutation in embryonic stem (ES) cells. Gene trap vectors both disrupt coding sequence and report on the genes' endogenous expression. The most popular gene trap reporter to date combines beta-galactosidase expression with neomycin resistance in a fusion protein known as beta-geo. Here we describe a refinement to this reporter that also incorporates real time fluorescent readouts. We have constructed a series of gene trap vectors incorporating a novel tripartite fusion protein consisting of EGFP, beta-galactosidase, and the neomycin or hygromycin resistance activities. Our results indicate that these triple fusions can function efficiently as reporters of endogenous trapped gene expression and subcellular localization. We show that these fusion proteins constitute versatile gene trap reporters whose activity can be detected in real time by fluorescence and in fixed tissue with a sensitive enzymatic activity.     

Bordetella pertussis fur gene restores iron repressibility of siderophore and protein expression to deregulated Bordetella bronchiseptica mutants.

We report the isolation and preliminary phenotypic characterization of manganese-resistant Bordetella bronchiseptica mutants with respect to deregulation of siderophore and iron-regulated protein expression. The fur gene of Bordetella pertussis was cloned by genetic complementation of this deregulated phenotype and confirmed as fur by nucleotide sequence analysis.