Rhythm in potassium uptake by a duckweed, Lemna gibba G3

The potassium uptake activity of the "flow-medium culture" ofa long-day duckweed, Lemna gibba G3, followed a circadian rhythmwhich persisted for more than 5 days under continuous light.The period of the rhythm was about 25 hr under 3000 lux at 26?Cand was slightly over-compensated against temperature, Q₁₀ beinga little less than 1.0. The amplitude of the rhythm was dependenton light intensity, and there was no potassium uptake in thedark. Magnesium uptake was affected by the potassium movementand showed circadian rhythmicity with a small amplitude underconditions where the potassium uptake was already saturated.Calcium uptake did not show any obvious rhythm. In Contrastto L. gibba, a short-day duckweed L. perpusilla 6746 displayedcircadian rhythm of potassium uptake only in the dark and notin the light. This rhythm did not persist beyond the secondcycle. (Received June 13, 1978; )     

Demonstration of acid phosphatase activity in antigenic glycoprotein fractions obtained from the culture filtrate of Pseudomonas pseudomallei.

Pseudomonas pseudomallei, the causative microorganism of melioidosis, was grown in Mueller-Hinton liquid medium, and glycoprotein fractions were separated from the culture filtrate by ammonium sulfate precipitation, gel-filtration with Sephadex G-75, and column chromatography with DEAE-cellulose. The fractions revealed acid phosphatase activity, and reacted to the sera from melioidosis patient in gel-diffusion precipitation assay.     

Identification of novel blood proteins specific for mammalian hibernation.

Mammalian hibernation is a unique physiological adaptation that allows the sustainment of life under extremely low body temperatures. In the chipmunk, we found four proteins related specifically to hibernation. These proteins started to diminish in concentration in the blood before and disappeared during hibernation. These proteins reappeared in the blood as hibernation ceased and remained during nonhibernation. The complete or partial amino acid sequences of the four proteins showed that three (27-, 25-, and 20-kDa) were previously unknown, whereas another (55-kDa) is highly homologous with alpha 1-antitrypsin. The three novel proteins are homologous, indicating that they are a family. In the NH2-terminal regions of these proteins, a collagen-like amino acid sequence is present, whereas in their COOH-terminal regions, two sequences, Ser-Ala-Phe-Ala-Val-Lys and Val-Trp-Leu-Glu, are conserved. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions and gel permeation chromatography under denaturating conditions revealed that the four proteins form a 140-kDa complex in the plasma fraction. The novel proteins were detected in blood of another hibernator, the ground squirrel, but not in rodent nonhibernators, namely tree squirrels and rats. The present finding is the first identification of a hibernation-specific protein. The presence of specific proteins in hibernators suggests the involvement of genetic factors in the control of hibernation. These proteins provide valuable tools for understanding molecular mechanisms of mammalian hibernation.     

Adsorption equilibrium in immunoaffnity chromatography with antibodies to synthetic peptides

The effects of charged residues in peptide antigens on the binding characteristics of polyclonal antipeptide antibodies were studied using immunoadsorbents prepared by coupling the antibodies to CNBr-activated Sepharose 4B. Among the antipeptide antibodies, an antibody to the peptide without charged residues showed the most stable interaction with the peptide to the changes in pH. Conversely, the binding affinity of antibodies to the pep-tides with histidine residues having a unique pKa value of 6.0 decreased steeply with pH at around 6.0. The binding affinity of an antibody to the peptide with many charged residues decreased steeply with an increase in the ionic strength (adjusted by NaCl). Since circular dichroism (CD) spectrum measurements indicate that these peptides show disordered structures in the pH range of adsorption measurement, the dependence of peptide-antibody interaction on environmental conditions is attributed to the characteristics of side chains of the peptides. These results indicate that the dependence of the binding affinity of antipeptide antibodies on pH and the ionic strength is dominantly affected by the number and the pKa values of charged residues in the peptides.     

Role of prostaglandin endoperoxides in the serum thiobarbituric acid reaction

In the presence of heme and reduced glutathione, prostaglandin (PG) endoperoxides underwent rapid conversion to malondialdehyde and 12l-hydroxy-5,8,10-heptadecatrienoic acid. In addition, PG endoperoxides as well as lipid peroxides produced malondialdehyde to yield a red pigment during the thiobarbituric acid reaction with different efficiencies. The relative rates of the reaction were: 1,1,3,3-tetraethoxypropane, 100; PGG₂, 55; PGH₂, 32; and 15-hydroperoxyarachidonic acid, 6. The thiobarbituric acid reactive materials in rabbit serum decreased by 25–60%, after intravenous administration of aspirin (a cyclo-oxygenase inhibitor) and with a concomitant decline of serum PG levels. These results, taken together, suggested that serum thiobarbituric acid values, considered to be an indicator of lipid peroxide levels, were to a significant extent due to PG endoperoxides and their derivatives.     

Ultrastructural study of mycobacteria in experimentally produced lung lesions of mice.

Mice were infected by iv injection with a virulent strain of Mycobacterium bovis, Ravenel strain, to prepare specimens for electron microscopical observation of their intracellular morphology. Observation was made with ultra-thin sections of the granulomatous lungs at an advanced stage of infection. Many apparently intact bacterial cells were found intracellulary, and the majority of them had lipoidal inclusions enclosed by a membranous structure. Several layers of mycobacterial cell wall were discernible, including a fairly wide space of the electron-transparent zone just beneath the electrondense outmost layer. Mesosomes, nuclear material, small dense granules and cross wall were found in almost the same appearance as those reported of mycobacteria grown in vitro. The bacilli were located mainly within intact or damaged phagosomes which were often filled with amorphous material of various electron densities.