Characterization of the IS895 family of insertion sequences from the cyanobacterium Anabaena sp. strain PCC 7120.

A family of repetitive elements from the cyanobacterium Anabaena sp. strain PCC 7120 was identified through the proximity of one element to the psbAI gene. Four members of this seven-member family were isolated and shown to have structures characteristic of bacterial insertion sequences. Each element is approximately 1,200 bp in length, is delimited by a 30-bp inverted repeat, and contains two open reading frames in tandem on the same DNA strand. The four copies differ from each other by small insertions or deletions, some of which alter the open reading frames. By using a system designed to trap insertion elements, one of the elements, denoted IS895, was shown to be mobile. The target site was not duplicated upon insertion of the element. Two other filamentous cyanobacterial strains were also found to contain sequences homologous to IS895.     

Structural features of methyl-accepting taxis proteins conserved between archaebacteria and eubacteria revealed by antigenic cross-reaction.

A number of eubacterial species contain methyl-accepting taxis proteins that are antigenically and thus structurally related to the well-characterized methyl-accepting chemotaxis proteins of Escherichia coli. Recent studies of the archaebacterium Halobacterium halobium have characterized methyl-accepting taxis proteins that in some ways resemble and in other ways differ from the analogous eubacterial proteins. We used immunoblotting with antisera raised to E. coli transducers to probe shared structural features of methyl-accepting proteins from archaebacteria and eubacteria and found substantial antigenic relationships. This implies that the genes for the contemporary methyl-accepting proteins are related through an ancestral gene that existed before the divergence of arachaebacteria and eubacteria. Analysis by immunoblot of mutants of H. halobium defective in taxis revealed that some strains were deficient in covalent modification of methyl-accepting proteins although the proteins themselves were present, while other strains appeared to be missing specific methyl-accepting proteins.     

Biopharmaceutical studies of spirobishexahydropyrimidine.

Oral administration of spirobishexahydropyrimidine showed an increase in the activity of serum transaminases, lactate dehydrogenase and alkaline phosphatase. Biological half life and other pharmacokinetic parameters showed rapid absorption and slow elimination of the drug.     

Expression of reg/PSP, a pancreatic exocrine gene: relationship to changes in islet beta-cell mass

A cDNA termed reg was recently isolated by differential screening of a library prepared from regenerating islets isolated from pancreatic remnants of rats subjected to 90% pancreatectomy and nicotinamide treatment. This led to speculation that this gene may be involved in expansion of beta-cell mass. In the current study we have measured reg expression after implantation and resection of a solid insulinoma tumor into rats, maneuvers known, respectively, to reduce and reexpand the volume of beta-cells in the islet. Animals with an implanted insulinoma tumor became profoundly hypoglycemic. Islet beta-cells declined from the normal 75% of total islet volume to less than 30%, in concert with a marked reduction in the reg mRNA level. Removal of the tumor resulted in a sharp increase in beta-cell replication, as measured by [3H]thymidine incorporation and a return to normal beta-cell volume within 4 days of tumor resection. This was associated with a transient induction in reg expression compared to that in tumor-bearing animals, effectively returning the amount of reg mRNA to the levels found in normal animals within 48 h; at later time points after tumor removal (3-7 days) reg expression declined, but then rose toward normal. In situ hybridization analysis localized the initial induction in reg mRNA expression to the exocrine pancreas. Continuous infusion of insulin into normal rats for 4 days, a maneuver that does not significantly reduce beta-cell mass, resulted in dramatically reduced insulin mRNA in islets, but no change in the levels of reg mRNA. We conclude that the diminution in pancreatic beta-cell mass caused by subcutaneous implantation of an insulinoma is associated with reduced reg gene expression and that the increase in beta-cell replication after resection of the tumor is preceded by return of reg gene expression toward normal.     

Relation of birth weight and childhood respiratory infection to adult lung function and death from chronic obstructive airways disease.

OBJECTIVE--To examine whether birth weight, infant weight, and childhood respiratory infection are associated with adult lung function and death from chronic obstructive airways disease. DESIGN--Follow up study of men born during 1911-30 whose birth weights, weights at 1 year, and childhood illnesses were recorded at the time by health visitors. SETTING--Hertfordshire, England. SUBJECTS--5718 men born in the county during 1911-30 and a subgroup of 825 men born in the county during 1920-30 and still living there. MAIN OUTCOME MEASURES--Death from chronic obstructive airways disease, mean forced expiratory volume in one second (FEV1) and forced vital capacity (FVC), and respiratory symptoms. RESULTS--55 men died of chronic obstructive airways disease. Death rates fell with increasing birth weight and weight at 1 year. Mean FEV1 at age 59 to 70 years, adjusted for height and age, rose by 0.06 litre (95% confidence interval 0.02 to 0.09) with each pound (450 g) increase in birth weight, independently of smoking habit and social class. Bronchitis or pneumonia in infancy was associated with a 0.17 litre (0.02 to 0.32) reduction in adult FEV1 and with an increased odds ratio of wheezing and persistent sputum production in adult life independently of birth weight, smoking habit, and social class. Whooping cough in infancy was associated with a 0.22 litre (0.02 to 0.42) reduction in adult FEV1. CONCLUSIONS--Lower birth weight was associated with worse adult lung function. Intrauterine influences which retard fetal weight gain may irrecoverably constrain the growth of the airways. Bronchitis, pneumonia, or whooping cough in infancy further reduced adult lung function. They also retarded infant weight gain. Consistent with this, death from chronic obstructive airways disease in adult life was associated with lower birth weight and weight at 1 year. Promoting lung growth in fetuses and infants and reducing the incidence of lower respiratory tract infection in infancy may reduce the incidence of chronic obstructive airways disease in the next generation.     

Biopharmaceutical studies of 3-substituted isatin derivatives

The metabolic fate of isatin hydrazone (Ia), isatin-3-thiosemicarbazone (Ib), isatin-3-semicarbazone (Ic), isatin-3-phenylhydrazone (Id), isatin oxime (Ie) and 3-hydroxy-3-acetonyl oxindole (II) was studied in rabbits. The compounds were administered orally in the dose of 300 mg/kg body wt. Isatin anthranilic acid, tryptophan and nicotinic acid were identified as the major metabolites excreted in urine. The 3-hydroxy-3-acetonyl oxindole (II) gave on additional metabolite, oxindole. The major metabolites were separated and identified unambiguously on thin layer silica gel plate. Metabolic pathways have been proposed to explain the biotransformation of the compounds investigated.     

Dinoflagellate sterols IV: Isolation and structure of 4α,23ξ,24ξ-trimethylcholestanol from the dinoflagellate Glenodiniumhallii

The dinoflagellate $\text{Glenodinium}$$\text{hallii}$ was investigated for its sterol composition. Five of the six sterols were isolated and identified as cholest-5-en-3β-ol, (24ξ)-24-methylcholest-5-en-3β-ol, stigmasta-5,22-dien-3β-ol, (22E,24R)-4α,23,24-trimethyl-5α-cholest-22-en-3β-ol, and 4α,23ξ,24ξ-trimethyl-5α-cholestan-3β-ol.