In vitro propagation of cassava (Manihot esculenta Crantz)

A method is presented for the rapid in vitro propagation of cassava (Manihot esculenta Crantz). Nodal explants were induced to grow as multiple-shoot cultures on a medium containing 1.0 M 6-benzylamino purine (BAP), supplemented with 0.25 M -naphthaleneacetic acid (NAA). Nodes were removed from the shoots after three weeks of growth and subcultured on fresh culture medium. An average of 7.0 nodes were produced from each explanted node after three weeks in culture. Nodal explants were transferred to a medium containing 2.5 M indole-3-butyric acid (IBA) to improve root initiation on the developing plantlets. Plant establishment was possible upon transfer to soil. In vitro propagation offers enhanced rates of multiplication over more conventional methods of propagation. In addition, in vitro propagation facilitates the storage and international exchange of cassava germplasm.     

DNA-dependent RNA polymerase from Spirochaeta aurantia

Abstract A DNA-dependent RNA polymerase was isolated from Spirochaeta aurantia . The M _r values of the holoenzyme subunits are 164000, 142000, 84000, and 44500. The RNA polymerase activity was sensitive to heparin, streptolydigin, and actinomycin D, while rifampicin and streptovaricin did not inhibit activity.     

Immobilization of glucoamylase and glucose oxidase in activated carbon: effects of particle size and immobilization conditions on enzyme activity and effectiveness

Glucoamylase and glucose oxidase have been immobilized on carbodiimide-treated activated carbon particles of various sizes. Loading data indicate nonuniform distribution of immobilized enzyme within the porous support particles. Catalysts with different enzyme loading and overall activities have been prepared by varying enzyme concentration in the immobilizing solution. Analysis of these results by a new method based entirely upon experimentally observable catalyst properties indicates that intrinsic catalytic activity is reduced by immobilization of both enzymes. Immobilized glucoamylase intrinsic activity decreases with increasing enzyme loading, and similar behavior is suggested by immobilized glucose oxidase data analysis. The overall activity data interpretation method should prove useful in other immobilized enzyme characterization research, especially in situations where the intraparticle distribution of immobilized enzyme is nonuniform and unknown.     

The effect of soil water status on critical phosphorus concentrations inStylosanthes hamata cv. Verano

Summary The effect of soil water status on the critical phosphorus concentration (CPC) determined in apices and whole tops ofStylosanthes hamata cv. Verano was investigated in a glasshouse trial. The species was grown with six rates of P and three ranges of soil water potential and was harvested at 10 and 14 weeks after germination. The CPC of both whole tops and apices decliced between the two harvests. At the first harvest the CPC of both whole tops and apices increased as the soil water potential decreased but at the second harvest there was no effect of soil water potential on CPC. It is suggested that at the earlier harvest water stress was delaying physiological development, resulting in a CPC characteristic of chronologically younger tissue, but that by the second harvest the decline in CPC with age had ceased for all water treatments.     

Effect of mouse genotype on interferon production. I. Lines congenic at theIf-1 locus

The level of circulating Interferon induced in mice by Newcastle disease virus is controlled by a single codominant locus,If-1, with two alleles,If-1 ^l for low andIf-1 ^h for high production. This locus is linked to the histocompatibility locusH-28. Of three C57BL/6By lines congenic for the BALB/cBy allele atH-28, two are carrying the BALB/cBy allele and one, the C57BL/6By allele atIf-1. Thus, mouse strains that are genetically very similar but different in their production of NDV-induced circulating Interferon now are available.A preliminary report of these studies was presented at the ASM meeting at Miami Beach in May 1973.     

The isolation and characterisation of gas-cylinder membranes and α-granules fromAnabaena flos-aquae D 124

Summary Gas-cylinder membranes and -granules were isolated from cells of the blue-green alga,Anabaena flos-aquae D 124. Gas-cylinder membranes, which are 1,100 Å wide after isolation, show striations having a periodicity of 50 Å. The membranes appear globular in section with a spacing of about 40 Å between globules. There are strong indications that the globules are proteinaceous with molecular weights of 22,000±2,000. Possible homologies of these membranes with viral coat protein are discussed. -granules were shown by a variety of techniques to be polysaccharide.