Isolation of a recombinant lambda phage carrying nusA and surrounding region of the Escherichia coli K-12 chromosome

Summary A recombinant bacteriophage lambda, argG-6, has been isolated which carries the argG gene and neighbouring loci on an EcoRI-generated 15.5 Kb DNA fragment from the Escherichia coli chromosome. The locations of the argG, nusA and pnp genes on the 15.5 Kb DNA fragment have been determined. In the case of nusA, a Tn5 insertion and sub-cloning of restriction fragments were used to locate the gene. The gene products of nusA and pnp have been identified on one- and two-dimensional polyacrylamide gels. The clockwise gene order was found to be argG-nusA-pnp.     

Familial Mediterranean Fever: Recent Advances in Pathogenesis and Management

The success of colchicine therapy in the management of familial Mediterranean fever has provided new direction to investigations into the pathogenesis of this disease. Examination of HLA antigen frequencies in 53 patients with familial Mediterranean fever and appropriate controls, as well as various immunologic studies have yielded no significant differences. However, B lymphocyte typing and assays for immune complexes, lymphokines and prostaglandins may be of potential interest. Preliminary studies indicate that leukocytes of patients with familial Mediterranean fever release increased amounts of lysozyme (P<0.01), when subjected to high temperatures, and of both lysozyme and myeloperoxidase at low osmotic concentrations. The known and potential effects of colchicine on leukocyte and cellular metabolism, and the current status of colchicine prophylaxis are reviewed. In patients receiving an optimum colchicine dose of 1.5 to 1.8 mg per day, side effects have been minimal and the frequency of attacks has been decreased significantly.     

Fish community structure in lakeshore lagoons on long point,lake Erie,Canada

Synopsis The interaction of fluctuating water level and the Long Point topography is discussed with regard to the formation of lake-shore lagoons and their subsequent invasion by fishes. The species composition of fish communities in these lagoons was determined by 12 collections from lagoons (23 m² to 25 ha) which yielded 33 fish species. The relationship of the number of fish species to lagoon area was lognormal; that is, with increasing lagoon area the number of species rose rapidly at first but soon decreased sharply, probably limited by the number of species capable of surviving in the habitat. The marked effect of area on species number in small lagoons is considered in the context of a hypothetical seasonal pattern of occasional invasion and continuous extinction.A sequence of reproductive guilds was found. In beach lagoons psammophils and lithophils were dominant. In a large vegetated lagoon in the interior phytophils and speleophils were dominant. This sequence was paralleled by an increase in the proportion of guarding and nesting species in the communities. The sequence was disrupted in the small interior lagoons where adaptations for survival were more important than reproductive strategy.     

The role of glucagon in the regulation of blood glucose: Model studies

Mathematical models afford a procedure of unifying concepts and hypotheses by expressing quantitative relationships between observables. The model presented indicates the roles of both insulin and glucagon as regulators of blood glucose, albeit in different ranges of the blood glucose concentrations. Insulin secretion is induced during hyperglycemia, while glucagon secretion results during hypoglycemia. These are demonstrated by simulations of a mathematical model conformed to data from the oral glucose tolerance test and the insulin infusion test in normal control subjects and stable and unstable diabetic patients. The model studies suggest the parameters could prove of value in quantifying the diabetic condition by indicating the degree of instability. Presented at the Society for Mathematical Biology Meeting, University of Pennsylvania, Philadelphia, August 19–21, 1976.     

Description of the neotype ofRepomucenus sagitta (Callionymidae) with comments on the species

The neotype ofRepomucenus sagitta is described. Specimens conspecific with the neotype from India, the Gulf of Thailand, the South China Sea, the Yellow Sea and Australia are described. Sexual characters, geographic variation, habitat and geographic distribution were noted.Repomucenus macdonaldi is a junior synonym ofR. sagitta as defined by the neotype.     

Contrasts between subsurface microbial communities and their metabolic adaptation to polycyclic aromatic hydrocarbons at a forested and an urban coal-tar disposal site

The abundance and distribution of microorganisms and their potential for mineralizing polycyclic aromatic hydrocarbons (PAHs) were measured in subsurface sediment samples at two geographically separate buried coal-tar sites. At a relatively undisturbed forested site in the northeastern United States, metabolic adaptation to the PAHs was evident: Radiolabeled naphthalene and phenanthrene were converted to ¹⁴CO₂ in core material from inside but not outside a plume of groundwater contamination. However, at the urban site in the midwestern United States these PAHs were mineralized in sediments from both contaminated and uncontaminated boreholes. Thus, clear qualitative evidence showing an adaptational response by the subsurface microbial community was not obtained at the urban site. Instead, subtler clues suggesting metabolic adaptation by subsurface microorganisms from the urban site were discerned by comparing lag periods and extents of ¹⁴CO₂ production from radiolabeled PAHs added to samples from contaminated and uncontaminated boreholes. Despite slightly higher PAH mineralization activity in contaminated borehole samples, p-hydroxybenzoate was mineralized equally in all samples from the urban site regardless of location. No striking trends in the abundances of actinomycetes, fungi, and either viable or total bacteria were encountered. However, colonies of the soil bacterium, Bacillus mycoides, were detected on enumeration plates of several samples from unsaturated and saturated zones in both urban boreholes. Furthermore, other common soil bacteria, Myxococcus xanthus and Chromobacterium violaceum, were identified in samples from the uncontaminated urban borehole. The occurrence of bacteria usually restricted to surface soil, combined with the observation of fragments of building materials in many of the core samples, suggested that past excavation and backfilling operations may have caused mixing of surface soil with subsurface materials at the urban site. We speculate that this mixing, as well as non-coal-tar-derived sources of PAHs, contributed to the PAH-mineralizing activity present in the sediment samples from the uncontaminated urban borehole.     

Roles of iron in neoplasia

Research and clinical observations during the past six decades have shown that: 1. Iron promotes cancer cell growth; 2. Hosts attempt to withhold or withdraw iron from cancer cells; and 3. Iron is a factor in prevention and in therapy of neoplastic disease. Although normal and neoplastic cells have similar qualitative requirements for iron, the neoplastic cells have more flexibility in acquisition of the metal. Excessive iron levels in animals and humans are associated with enhanced neoplastic cell growth. In invaded hosts, cytokine-activated macrophages increase intracellular ferritin retention of the metal, scavenge iron in areas of tumor growth, and secrete reactive nitrogen intermediates to effect efflux of nonheme iron from tumor cells. Procedures associated with lowering host intake of excess iron can assist in prevention and in management of neoplastic disease. Chemical methods for prevention of iron assimilation by neoplastic cells are being developed in experimental and clinical protocols. The antineoplastic activity of a considerable variety of chemicals, as well as of radiation, is modulated by iron. The present article focuses on recent findings and suggests directions for further cancer-iron research.