Immobilization of enzymes on spheron: 1. Trypsin and glucoamylase by the titanium-chelation method

In a preliminary study, trypsin (EC 3.4.21.4) and glucoamylase (exo-1,4-α-d-glucosidase, 1,4-α-d-glucan glucohydrolase, EC 3.2.1.3) were immobilized on Spheron by the titanium-chelation method. The activity of trypsin immobilized on Spheron P100 000 was higher against tosyl-l-arginine 4-nitroanilide than against casein. The variation in the specific activities of glucoamylase immobilized on Spherons of different porosities to wards substrates of different molecular weights was examined.     

In vivo biosynthesis of the saturated isoprene unit of dolichyl phosphate

Reduction of the e-isoprene unit of polyprenols to form dolichols was studied in vivo using³H-polyprenol derivatives as substrates and liposomes as carriers. Liposomes containing labeled polyprenol, polyprenyl phosphate, or polyprenyl pyrophosphate were injected through the portal vein into the livers of rats under anesthesia. Uptake and conversion of the labeled compounds to dolichol derivatives was studied at different intervals. The greatest conversion to dolichol derivatives was found with polyprenyl pyrophosphate and polyprenyl monophosphate, with 31% and 8% of the absorbed dose converted respectively. Less than 0.2% of the absorbed polyprenol was converted to dolichol derivatives. These results suggest that the substrate for the -isoprene reductase involved in dolichol biosynthesis is either polyprenyl monophosphate or polyprenyl pyrophosphate, or both.     

Active Ca2+ transport by membrane vesicles from pigeon erythrocytes Stimulation by amino acids,ATP, GTP,P1 and some other cell constituents

Pretreatment of pigeon erythrocyte membrane vesicles with amino acids, ATP, GTP, P_i and some other simple cell constituents (singly and in combination) causes an increase in ATP-dependent Ca²⁺-uptake activity of vesicles upon subsequent incubation with ⁴⁵Ca²⁺ after removal of the above agents from the ‘i’ face. Amino acids augment the stimulation by all stimulatory agents and are required for stimulation by P_i. The effects of amino acids, ATP, GTP and P_i all occur at physiological concentrations. Many if not all of the effects of the mixture of amino acids that occur naturally in the cells can be accounted for by the group transported by the ‘ASC’ transport system of Christensen (Christensen H.N. (1975) Biological Transport, 2nd edn., W.A. Benjamin, Inc., Reading, MA), but not by any single amino acid at its physiological concentration. The effects of ATP and GTP are not mimicked by their non-hydrolysable β, γ-imido analogues nor by the corresponding 3′, 5′-cyclic monophosphates. None of the effects described appears to involve calmodulin. We suggest that amino acid transport plays a role in metabolic regulation through effects on cell [Ca²⁺]. Analogous effects on cell [Ca²⁺] may be involved in the action of the many hormones which augment amino acid accumulation by the ‘A’ amino acid transport system.     

Isoproterenol-induced selective phosphorylation invivo of the 214,000 dalton subunit of rat C6 glioma cell RNA polymerase II

The phosphorylation $\text{in}\text{vivo}$ of RNA polymerase II after isoproterenol stimulation of confluent rat C6 glioma cell cultures has been investigated. Glioma cells were incubated in the presence of Na₂H³²PO₄ and stimulated for 1 hour with the β-adrenergic agonist isoproterenol. The phosphorylation pattern was analyzed after purification of RNA polymerase II by immunoprecipitation, SDS-polyacrylamide gel electrophoresis and autoradiography. Isoproterenol markedly increased [³²P]phosphate incorporation into the 214,000 dalton RNA polymerase subunit. Analysis of the phosphate acceptor amino acid revealed the presence of only [³²P]phosphoserine. The data demonstrates an isoproterenol-induced structural modification of RNA polymerase II.     

Actin acetylation in Drosophila tissue culture cells

In a permanent cell line derived from Drosophila embryos, cytoplasmic actin is produced as an unstable precursor, which is subsequently converted to a stable form. This conversion results in a reduction in isoelectric point, with no apparent change in molecular weight. The conversion involves an enzymatic acetylation, and results in an insensitivity to aminopeptidase digestion, suggesting N-terminal blockage. Both the acetylated and unacetylated actins can participate in the assembly of F-actin, but with different efficiencies.This work was supported by a grant from the NIH (GM 22866).     

Structure of cellulose II hydrate

A hydrate of cellulose II can be formed by swelling Fortisan fibers in hydrazine and then washing in water. The hydrate is stable at 93% relative humidity and has a monoclinic unit cell with dimensions a = 9.02 Å, b = 9.63 Å, c = 10.34 Å, and γ = 116.0°; the space group is P2₁. The unit cell contains disaccharide sections of two chains and approximately four water molecules. The structure was refined using the LALS method, based on 10 observed and 10 unobserved reflections. An antiparallel arrangement of adjacent chains was assumed, since this occurs in cellulose II (the starting material), and the hydrate also reverts to cellulose II on dehydration. Refinement of the positions and side-chain conformations of the chains shows that the chains are stacked in the same way as in cellulose II, and the hydrate is formed by insertion of water molecules between the stacks. However, all efforts to arrange the water molecules in crystallographically regular positions led to unsatisfactory agreement between the observed and calculated intensities. These results suggest an irregular arrangement of the water molecules, which was modeled using water-weighted atomic scattering factors. The analysis resulted in two refined models with relative chain staggers of ～ +c/4 and ～ -c/4, which are indistinguishable in terms of the x-ray agreement. Our preference is for the +c/4 model, for which the stacks of chains are analogous to those in cellulose II.     

Seroimmunological and parasitological surveys of leucocytozoon caulleryi infection in chickens in several asian countries

Epizootiological surveys of Leucocytozoon caulleryi infection in chickens in Japan, Taiwan, Philippines, Singapore, Malaysia and Thailand were undertaken by means of the immunodiffusion test. The rate of infection of L. caulleryi confirmed by the examination of parasites in the peripheral blood of chickens coincided with that of positive antibody response in the immunodiffusion test. Antibodies against L. caulleryi were found in chickens in all the countries surveyed in the present investigation. The prevalence of L. caulleryi infection in chickens was confirmed by the immunodiffusion test. Several chickens in each country showed the presence of serum antigens of L. caulleryi at the times of serum sample collection. These results seemed to indicate that the immunodiffusion test is a method efficient enough to be applicable to the epizootiological surveys and diagnosis of L. caulleryi infection in chickens in the field. As a result, the antibodies or soluble antigens in the sera of chickens infected with L. caulleryi present, respectively, in each country may have the same immunological characters.     

An ecological study of the rare rotifer species Trochosphaera solstitialis (Thorpe 1893) and the first report of the male

An ecological study of the rotifer species Trochosphaera solstitialis (Thorpe, 1893) was conducted for a period of eight months in a temporary pond in eastern Texas, U.S.A. The pond was found to be environmentally stressed and contained large amounts of decomposing vegetation. Physico-chemical factors contributing to the stressed conditions were low dissolved oxygen concentrations, low pH values, high ammonia concentrations, and high color values caused by large concentrations of iron, tannin and lignin. Large concentrations of iron, tannin, and lignin seem to be highly correlated with T. solstitialis populations. Physicochemical conditions probably eliminated predators of the rotifer, such as fish. Males of T. solstitialis were observed which never left the body cavity of the female. Males probably do not feed with an apparent rudimentary digestive system.