Variation in Quantitative Requirements for Na for Transport of Metabolizable Compounds by the Marine Bacteria Alteromonas haloplanktis 214 and Vibrio fischeri

The rates of uptake by Alteromonas haloplanktis of 19 metabolizable compounds and by V. fischeri of 16 of 17 metabolizable compounds were negligible in the absence of added alkali-metal cations but rapid in the presence of Na. Only d-glucose uptake by V. fischeri occurred at a reasonable rate in the absence of alkali-metal cations, although the rate was further increased by added Na, K, or Li. Quantitative requirements for Na for the uptake of 11 metabolites by A. haloplanktis and of 6 metabolites by V. fischeri and the characteristics of the Na response at constant osmotic pressure varied with each metabolite and were different from the Na effects on the energy sources used. Li stimulated transport of some metabolites in the presence of suboptimal Na concentrations and for a few replaced Na for transport but functioned less effectively. K had a small capacity to stimulate lysine transport. The rate of transport of most of the compounds increased to a maximum at 50 to 300 mM Na, depending on the metabolite, and then decreased as the Na concentration was further increased. For a few metabolites, the rate of transport continued to increase in a biphasic manner as the Na concentration was increased to 500 mM. Concentrations of choline chloride equimolar to inhibitory concentrations of NaCl were either not inhibitory or appreciably less inhibitory than those of NaCl. All metabolites examined accumulated inside the cells against a gradient of unchanged metabolite in the presence of Na, even though some were very rapidly metabolized. The transport of l-alanine, succinate, and d-galactose into A. haloplanktis and of l-alanine and succinate into V. fischeri was inhibited essentially completely by the uncoupler 3,5,3',4'-tetrachlorosalicylanilide. Glucose uptake by V. fischeri was inhibited partially by 3,5,3',4'-tetrachlorosalicylanilide and also by arsenate and iodoacetate.     

Quantitative exfoliative oral cytology in iron-deficiency and megaloblastic anemia

A study was undertaken to ascertain if there were any morphometric or morphologic changes in exfoliated oral squames in either iron-deficiency or vitamin B12-deficiency states. The results revealed a significant (P less than .05) increase in nuclear area and a significant alteration in nuclear/cytoplasmic ratio in vitamin B12 deficiency; both returned to normal following replacement therapy. No changes were seen with iron deficiency anemia or non-vitamin B12 megaloblastic anemia. Ultrastructurally, the surface morphology showed similar features in all groups, with the plasma membrane forming complex folds (microplications) in three patterns: branching, parallel and network. The microplication widths and interplication distances were remarkably constant in both control and study groups, regardless of pattern.     

Influence of added limestone and fertilizers upon the micro-nutrient content of forage tissue and soil

Summary Five rates of limestone and 4 rates of fertilizers were used in a split-plot design to study their effects under field conditions on Mo, Cu, B, Mn, and Zn levels in mixed forage tissue and soil, and on the forage yield. An increase in soil pH resulted in an increase in Mo and Cu content of plant tissue while B, Mn, and Zn decreased. The micro-nutrient content of the tissue increased as the harvesting season progressed. Increasing rates of applied fertilizer did not affect the micro-nutrient content of the forage tissue or soil. Liming to a pH of 5.6 and above reduced the availability of Mn and Zn in the soil. In general, the available B was low at pH values greater than 6.1. Lime did not affect the quantities of Mo and Cu in the soil. Manganese is supplied in large quantities by limestone and is not apt to be deficient in limed soil. However, addition of B and Zn may be required on the high pH soils of Eastern Canada in future. Molybdenum was adequate where the soil was limed to a pH of 6.1 or greater. The dry-matter yield of forage increased significantly with successive increases in lime up to pH 6.6 and with each increment of fertilization. Contribution No.226, Research Branch, Research Station, P.O. Box 1210, Charlottetown, P.E.I. and No.166, Experimental Farm, Nappan, N.S.     

Effect of N,P, and K on root yield and nutrient levels in the leaves and roots of rutabagas grown in a greenhouse

Summary Experiments were conducted to determine the influence of N, P, and K and of the NP and NK interactions on root yields and tissue concentrations of N, P, and K of rutabagas grown on a sandy loam soil under greenhouse conditions. Root yields were increased by applications of N and K but not by added P. The yield response to N was dependent on K supply. The highest dry matter content in roots was associated with the lowest rates of N and K and the lowest root yields. The N content of tissue at the early vegetative stage increased with increasing rates of N and decreased with increasing rates of P and K. The N content of root tissue at harvest increased at the highest rates of N but was unaffected by rates of P and K. The P and K content of root tissue increased with increasing rates of P and K, respectively. The levels of nutrients in early vegetative tissue associated with optimum yields were about 2.6, 0.24, and 2.0% for N, P, and K, respectively. The corresponding values in the leaf tissue at harvest were about 1.2, 0.12, and 1.5% N, P, and K, respectively. Contribution No.222.     

Selective esterification of 1,6-anhydrohexopyranoses: The possible role of intramolecular hydrogen-bonding

Selective esterification reactions of 1,6-anhydro-3-deoxy-β-D-xylo-hexopyranose(1), 1,6-anhydro-β-D-glucopyranose (7), and several derivatives of 7, were conducted with an acid chloride or acid anhydride in pyridine. Reaction of 1 with p-toluenesulfonyl chloride and with benzoyl chloride gave 70 and 63%, respectively, of the 2-esters. The 2-methyl and 2-benzyl ethers of 7, both having strongly hydrogen-bonded C-4 hydroxyl group, reacted with p-toluenesulfonyl chloride to yield the 4-monosulfonates (71 and 74%, respectively). Esterification of the 2-methyl ether and 2-p-toluenesulfonate of 7 with p-toluenesulfonic anhydride instead of with p-toluenesulfonyl chloride led to increased yields of the 4-p-toluenesulfonates after a shorter reaction-time.     

Sensitive rapid detection method for viable bacterial cells

A rapid sensitive method for the detection of viable bacterial cells is described in which P³² as inorganic orthophosphate is used to label the cells. Factors affecting the uptake of P³² by cells as well as the sensitivity of the method have been explored with suspensions of Aerobacter aerogenes. The uptake of P³²O₄ is dependent on several factors. Of various incubation media tested, one composed of 0.005 m KCl, 0.002 m MgSO₄ and 10 mg/ml of glucose was found to best stimulate the uptake of the tracer. Incubation time and temperature and level of isotope and of unlabeled P also affected uptake. Labeled cells were collected on a membrane filter for measurement of radioactivity. Under optimal conditions, as few as 23 viable cells per milliliter were detected in 1 hr with 95% confidence.     

The importance of intercalation in the covalent binding of benzo(a)pyrene diol epoxide to DNA

The primary mode of non-covalent interaction of the strong carcinogen, benzo(a)pyrene diol epoxide, with DNA is through intercalation. It has variously been suggested that intercalative complexes may be prerequisite for either covalent binding or DNA-catalysed hydrolysis of the epoxide or both. Geacintov [Geacintov, N. E. (1986). Carcinogenesis 7, 589.] has recently argued that intercalation is important in covalent binding and presented theoretical constructs consistent with this proposal. A more general theoretical model is presented here which includes the possibilities that either catalysis of hydrolysis or covalent binding of benzo(a)pyrene diol epoxide DNA can occur (a) in an intercalation complex, or (b) without formation of a detectable, physically bound complex. It is shown that a variety of possible mechanisms formulated under this general theory lead to equations for overall reaction rates and covalent binding fractions which are all of the same form with respect to DNA concentration dependence. A consequence of this is that experimental studies of the dependence of hydrolysis rates and covalent binding fractions on DNA concentration do not distinguish between the various possible mechanisms. These findings are discussed in relation to the interactions of benzo(a)pyrene diol epoxide with chromatin in cells.     

Loss of Rb activates both p53-dependent and independent cell death pathways in the developing mouse nervous system.

Extensive apoptosis occurs in the nervous system of mouse embryos homozygous mutant for a targeted disruption of the retinoblastoma (Rb) gene. This cell death is present in both the central (CNS) and peripheral nervous systems (PNS) and is associated with abnormal S phase entry of normally post-mitotic neurons. Aberrant proliferation in the CNS correlates with increased free E2F DNA binding activity and increased expression of cyclin E, an E2F target gene and critical cell cycle regulator. Cell death in the CNS is accompanied by increased levels of the p53 tumor suppressor gene product and increased expression of the p53 target gene, p21Waf-1/Cip-1. However, induction of p53 is not observed in the PNS of Rb-mutant embryos, nor does loss of p53 function inhibit cell death in the PNS. Surprisingly, p21Waf-1/Cip-1 is induced in the sensory ganglia of Rb-mutant embryos in a p53-independent manner. Although loss of p53 gene function prevents cell death in the CNS of Rb-mutant embryos, it does not restore normal proliferative control.     

Observations on the distinction between oligotrophic and eutrophic marine bacteria

The nutritional requirements of two marine bacteria designated as oligotrophic because they could grow on media containing 10 mg of C per liter supplied as peptone and two classified as eutrophic because they could grow only at higher concentrations of C supplied as peptone were examined. Each of the four organisms was found to have its own unique group of compounds which could serve either individually or in combination as sources of carbon and energy for growth. When the peptone in the medium was replaced by another appropriate source of carbon and energy, the difference in the capacity of the organisms examined to grow at 10 mg of C per liter disappeared, and all four organisms could be described as being oligotrophic. Some of the organisms required a low concentration of one specific carbon source but a higher concentration of another. One of the organisms was inhibited by high concentrations of one specific carbon source but not by another. The observations indicate that current methods of enumeration based on the capacity of cells to grow in the presence of high or low concentrations of complex mixtures of nutrients such as peptone do not distinguish between two broad classes of bacteria differing intrinsically in their ability to grow at high and low concentrations of nutrients. Whether two such broad classes exist seems extremely doubtful. Which organisms will multiply in a particular environment will depend on both the specific nutrients available and their concentrations.