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.     

FGFR-4, a novel acidic fibroblast growth factor receptor with a distinct expression pattern.

We have previously identified two novel members of the fibroblast growth factor receptor (FGFR) gene family expressed in K562 erythroleukemia cells. Here we report cDNA cloning and analysis of one of these genes, named FGFR-4. The deduced amino acid sequence of FGFR-4 is 55% identical with both previously characterized FGFRs, flg and bek, and has the structural characteristics of a FGFR family member including three immunoglobulin-like domains in its extracellular part. Antibodies raised against the carboxy terminus of FGFR-4 detected 95 and 110 kd glycoproteins with a protein backbone of 88 kd in COS cells transfected with a FGFR-4 cDNA expression vector. The FGFR-4 protein expressed in COS cells could also be affinity-labeled with radioiodinated acidic FGF. Furthermore, ligand binding experiments demonstrated that FGFR-4 binds acidic FGF with high affinity but does not bind basic FGF. FGFR-4 is expressed as a 3.0 kb mRNA in the adrenal, lung, kidney, liver, pancreas, intestine, striated muscle and spleen tissues of human fetuses. The expression pattern of FGFR-4 is distinct from that of flg and bek and the yet additional member of the same gene family, FGFR-3, which we have also cloned from the K562 leukemia cells. Our results suggest that FGFR-4 along with other fibroblast growth factor receptors performs cell lineage and tissue-specific functions.     

Lithium-induced decrease of brain inositol and increase of brain inositol-1-phosphate is transient

The effects of a single does of LiCl (2.5 or 10 mEq/kg) on brain inositol and inositol-1-phosphate (Ins1P), intermediates of brain phosphoinositude (PI) turnover, were determinated in male Han: Wistar rats. There was a remarkable, 36–58 fold elevation of brain Li⁺ as the single does of LiCl was increased 4-fold. Moreover, the accumulation of brain lithium was slow during repeated administration of LiCl. Brain lithium did not correlate with changes in brain PI turnover either after a single or repeated doses. Thus, after a single does of LiCl the increases in brain Ins1P were much less than the decreases in brain inositol. Also, brain inositol was significantly decreased only with the high dose of LiCl whereas brain Ins1P accumulation was more prominent with the lower dose. Moreover, repeated daily doses of LiCl only transiently increased brain Ins1P at 1 and 7 d whereas inositol remained at control levels throughout the 14 d observation period. Lithium probably caused the transient decrease in brain inositol by inhibiting several enzymes, in addition to the inhibition of myo-inositol mono-phosphates, in the PI cycle. Moreover, a slow dampening down of PI turnover by lithium, possible via an inhibitory action on G-protein-coupling, may also explain the present findings.     

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.     

CYP1A1 genetic polymorphisms,tobacco smoking and lung cancer risk in a French Caucasian population

The CYP1A1 gene encoding for an enzyme involved in the metabolic activation of important tobacco carcinogens could be implicated in smoking-induced lung cancer. Given the strong association between tobacco smoking and lung cancer, the effect of tobacco smoke exposure has to be taken into account when studying the potential association between lung cancer and CYP1A1 genotypes. The effect of two CYP1A1 genetic polymorphisms (Mspl and IIe-Val) on lung cancer risk were evaluated using peripheral blood DNA from 150 lung cancer patients and 171 controls. The Mspl sitepresent allele was found among 19.3% of both cases and controls and the variant allele Val among 6.7% of cases and 8.8% of controls. Lung cancer risks associated with the Mspl site-present allele (OR= 0.9; 95%Cl: 0.5-1.8) or with the Val allele (OR= 0.8; 95%Cl: 0.3-1.9) were not increased after adjustment for tobacco and asbestos exposures. These results persisted when analyses were stratified on smoking status, daily consumption of tobacco or duration of smoking. Similar findings were obtained when squamous cell or small cell carcinomas were studied separately. This study thus suggests a minor role for the known CYP1A1 gene polymorphisms in predisposition to lung cancer among Caucasian populations.     

Role of NAD(P)H:quinone oxidoreductase polymorphism at codon 187 in susceptibility to lung,laryngeal and oral/pharyngeal cancers

NAD(P)H:quinone oxidoreductase (NQO1) has been proposed to play a protective role against the toxic effects of benzo[a]pyrene quinones. The C⁶⁰⁹T base change in the NQO1 gene, resulting in a Pro¹⁸⁷Ser amino acid change in the protein, has been associated with deficient enzyme activity. We examined whether this polymorphism modified the risks of smoking-related cancers in a case-control study involving patients with lung cancer (n = 150), laryngeal cancer (n = 129), oral/pharyngeal cancer (n = 121) and control individuals (n = 172), all Caucasian smokers. No statistically significant associations were observed between the NQO1 genotypes and smoking-related cancers, although the Ser/Ser genotype was associated with a tendency towards increased risk for lung cancer (odds ratio [OR] = 2.2, 95% confidence interval [CI] 0.7-6.7) and for oral/pharyngeal cancer (OR = 2.3, 95% CI 0.6-8.2). No significant interaction between the NQO1 genotype and either smoking exposure or GSTM1 genotype was found. Our results are consistent with the hypothesis that lack of NQO1 activity may be involved in some smoking-related cancers. However, they were based on small numbers of individuals with the putative atrisk genotype, and the associations did not reach statistical significance. Moreover, these results contrast with those observed in some other ethnic populations, where a protective effect of the NQO1 Ser allele was found. Further studies are therefore clearly needed for a better understanding of the potential role of NQO1 activity in tobacco-related cancers.     

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.