Tn10 generated deletions of the ompB locus of Escherichia coli K12

Abstract We have isolated a set of Tn 10 -generated deletions starting from the distal end of the ompR envZ operon of Escherichia coli K12. Most of the deletions removed both ompR and envZ genes or ended in ompR . These deletions exhibited an OmpC⁻ OmpF⁻ phenotype. One deletion removed only part of envZ and the strain was phenotypically OmpC⁻ OmpF^+/−. This deletion of the distal part of envZ did not affect osmoregulation of ompC . However, ompF osmoregulation appeared reversed. High osmolarity in the growth medium resulted in production of OmpF close to the wild-type level.     

Vitamin E Status of Healthy Swedish Cattle*

Using high pressure liquid chromatography the serum concentration of vitamin E was measured in dairy cows fed either hay or silage as their main roughage, in calves fed milk-replacer, and in young intensively fed bulls. The concentrates fed to the cows, calves and bulls were supplemented with 5–10, 25 and 5–10 mg DL-α-tocopheryl acetate per kg, respectively, and the milk-replacer for the calves was supplemented with 50 mg DL-α-tooopheryl acetate per kg powder. Cows fed silage as their main roughage had higher serum vitamin E concentrations ( $${\rm{\bar x}}$$ : 3.8–5.2 mg/l) than cows fed only hay ( $${\rm{\bar x}}$$ : 2.5–4.1 mg/1). Lactating cows had higher vitamin E concentrations than dry cows ( $${\rm{\bar x}}$$ : 4.1–5.2 and 2.5–3.8 mg/l, respectively) and calves and bulls had much lower vitamin E concentrations ( $${\rm{\bar x}}$$ : 1.4 and 1.2 mg/l, respectively) than cows. Thirty per cent of the calves and 41 % of the bulls had serum vitamin E concentrations less than 1.0 mg/l, suggesting that in these animals the conventional level of supplementation of feeds with DL-α-tocopheryl acetate in Sweden is probably inadequate for the prevention of nutritional muscular degeneration and other negative effects.     

Serum Glutathione Peroxidase Activity and Blood Selenium in Pigs

Blood serum glutathione peroxidase activity and blood selenium concentration were measured in blood samples from pigs subjected to experimentally induced selenium deficiency and dietary selenium supplementation on graded levels. A highly significant correlation between blood selenium and serum GSH-Px activity in pigs, especially in selenium deficient pigs, was demonstrated. There was also a strong relationship between blood selenium concentration and serum GSH-Px activity in pigs receiving dietary selenium at graded levels. Serum GSH-Px activity exhibited an excellent close-response relationship to dietary selenium. Linear regression analysis showed that the increased serum GSH-Px activity was a function of the dietary selenium concentration. The fitness of serum in monitoring slight changes of the selenium status of pigs with help of the estimation of GSH-Px activity was discussed. The measurement of serum GSH-Px activity seems to provide a useful and rapid means for defining selenium requirements and for identifying selenium deficiency in growing pigs.     

Combined Therapeutic Effect of Dietary Selenium and Vitamin Ε on Manifested Vesd Syndrome in Weaned Pigs

By using a therapeutic dietary supplementation in pigs, which had developed the vitamin Ε and selenium deficiency (VESD) syndrome, the same amounts of α-tocopheryl acetate and selenium were found to be effective as under prophylactic conditions. The experiment thus supported the conclusions that the addition of 5 mg DL-α-tocopheryl acetate/kg and 135 μg selenium/kg to a diet, which contained only traces of vitamin Ε and selenium, represents a level of minimal requirement. Glutathione peroxidase activity in blood serum was used to evaluate the selenium status in pigs. A modified method for determination of tocopherol in fat tissue was described. The addition of 15 mg α-tocopheryl acetate/kg diet was demonstrated to be sufficient to maintain the tocopherol stores in body fat at an unchanged level.     

Conversion of type II procollagen to collagen in Vitro: Removal of the carboxy-terminal extension is inhibited by several naturally occurring amino acids,polyamines, and structurally related compounds

Chick embryo sterna, which actively synthesize type II procollagen, were pulse-labeled with radioactive proline; protein synthesis was then inhibited by unlabeled proline and cycloheximide. After the inhibition of protein synthesis, several amino acids, polyamines, or structurally related compounds were added to the incubation medium. The conversion of procollagen, first to two intermediates, pC-collagen and pN-collagen, and then to collagen, was monitored by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. The addition of 50 mm β-alanine, arginine, asparagine, glutamine, hydroxylysine, lysine, or ornithine, as well as agmatine, ?-aminocaproic acid, S-2-aminoethylcysteine, cadaverine, canavanine, putrescine, or spermine clearly inhibited the removal of the carboxy-terminal extension and pC-collagen accumulated; the removal of the amino-terminal extension was not affected. The inhibition of the conversion was reversible and unaffected by fetal calf serum. The results suggest that the conversion of type II procollagen to collagen requires at least two separate proteinases for the removal of amino-terminal and carboxy-terminal extensions. The results further suggest that naturally occurring molecules may be used to modulate the rate of conversion of procollagen to collagen, and development of analogs of these compounds may provide the means to interfere with excessive deposition of collagen in diseases with tissue fibrosis.     

Production of cyclomaltodextrin glucanotransferase of Bacillus circulans var. alkalophilus ATCC21783 in B. subtilis

Summary The cyclomaltodextrin glucanotransferase (CGTase, E.C. 2.4.1.19) gene from an alkalophilic Bacillus circulans var. alkalophilus ATCC21783 was cloned into Escherichia coli and B. subtilis. When cloned from E. coli to B. subtilis, the entire insert containing the CGTase gene was, depending on the plasmid construction, either unstable or the recombinant B. subtilis did not secrete the enzyme in significant amounts. To achieve efficient enzyme production in B. subtilis, the gene was placed under the control of the B. amyloliquefaciens -amylase promoter. In one of the constructions, both the promoter and the signal sequence of the gene were replaced with those of B. amyloliquefaciens, whereas in another construction only the promoter area was exchanged. The recombinant B. subtilis clones transformed with these plasmid constructions secreted CGTase into the culture medium 14 times as much as did the parental strain in shake flask cultures. In fermentor cultures in an industrially feasible medium the enzyme production was substantially higher, yielding 1.2 g/l of CGTase, which is about 33 times the amount of the enzyme produced by the parental strain in corresponding fermentations. Both of the plasmid constructions were stable when grown over 50 generations without antibiotic selection.     

Acquired liver fat is a key determinant of serum lipid alterations in healthy monozygotic twins

Objective: The effects of acquired obesity on lipid profile and lipoprotein composition in rare BMI‐discordant monozygotic (MZ) twin pairs were studied. Design and Methods: Abdominal fat distribution, liver fat (magnetic resonance imaging and spectroscopy), fasting serum lipid profile (ultracentrifugation, gradient gel‐electrophoresis, and colorimetric enzymatic methods), and lifestyle factors (questionnaires and diaries) were assessed in 15 BMI‐discordant (within‐pair difference [Δ] in BMI >3 kg/m²) and nin concordant (ΔBMI <3 kg/m²) MZ twin pairs, identified from two nationwide cohorts of Finnish twins. Results: Despite a strong similarity of MZ twins in lipid parameters (intra‐class correlations 0.42‐0.90, P < 0.05), concentrations of apolipoprotein B (ApoB), intermediate‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein 3a% (HDL3a%), and HDL3c% were higher (P < 0.05) and those of HDL cholesterol, HDL2‐C, and HDL2b% were lower (P < 0.01) in the heavier co‐twins of BMI‐discordant pairs. The composition of lipoprotein particles was similar in the co‐twins. When BMI‐discordant pairs were further divided into liver fat‐discordant and concordant (based on median for Δliver fat, 2.6%), the adverse lipid profile was only seen in those heavy co‐twins who also had high liver fat. Conversely, BMI‐discordant pairs concordant for liver fat did not differ significantly in lipid parameters. In multivariate analyses controlling for Δsubcutaneous, Δintra‐abdominal fat, sex, Δsmoking and Δphysical activity, Δliver fat was the only independent variable explaining the variation in ΔApoB, Δtotal cholesterol, and ΔLDL‐C concentration. Conclusions: Several pro‐atherogenic changes in the amounts of lipids but not in the composition of lipoprotein particles were observed in acquired obesity. In particular, accumulation of liver fat was associated with lipid disturbances, independent of genetic effects.     

Incident Hip Fractures among Community Dwelling Persons with Alzheimer’s Disease in a Finnish Nationwide Register-Based Cohort

Background

Previous cohort studies have shown that persons with Alzheimer’s disease (AD) have a higher risk of hip fractures but recent data from large representative cohorts is scarce.

Methods

We investigated the association between AD and prevalent and incident hip fractures in an exposure-matched cohort study conducted in Finland 2002–2009 (the Medication and Alzheimer’s disease in 2005 study; MEDALZ-2005). The study population included all community-dwelling persons with verified AD diagnosis in Finland on December 31, 2005 and one matched comparison person per AD case (N = 56,186, mean age 79.9 (SD 6.8) years, range 42–101 years). The diagnosis of AD was extracted from a special reimbursement register. Data on hip fractures during 2002–2009 was extracted from the Finnish National hospital discharge register. Analyses of incident hip fractures (n = 2,861) were restricted to years 2006–2009.

Results

Persons with AD were twice as likely to have previous hip fracture in 2005 (odds ratio, 95% confidence interval 2.00, 1.82–2.20) than matched aged population without AD. They were also more likely to experience incident hip fracture during the four-year follow-up (hazard ratio, 95% confidence interval 2.57, 2.32–2.84, adjusted for health status, psychotropic drug and bisphosphonate use). The AD-associated risk increase decreased linearly across age groups. Although people with AD had higher risk of hip fractures regardless of sex, the risk increase was larger in men than women.

Conclusion

Findings from our nationwide study are in line with previous studies showing that persons with AD, regardless of sex or age, have higher risk of hip fracture in comparison to general population. Although there was some suggestion of effect modification by age or sex, AD was consistently associated with doubling of the risk of incident hip fracture.