Formation of functionally active chloroplasts is determined at a limited stage of leaf development in virescent mutants of rice

The ability to form functionally active chloroplasts is determined at a certain early stage of leaf development in three non-allelic temperature-sensitive virescent mutants of rice. Temperature-shift analysis, together with anatomical observations, indicates that the intrinsic developmental signals of the virescent genes are expressed at the stage immediately following the formation of basic leaf structure, but just before the onset of leaf elongation. These signals control the expression of chloroplast-encoded genes but do not affect the subsequent morphological development of the leaf or the photo-regulation of the expression of nuclear genes encoding chloroplast proteins.     

Lipase modification by various synthetic polymers for use in chloroform

Summary Lipase was modified with several hydrophilic and hydrophobic synthetic polymers. The modified lipase was solubilized into chloroform by. The catalytic esterification activity of modified lipase increased linearly with the increase of its solubility in chloroform.     

Excretion of peroxidase from horseradish hairy root in combination with ion supplementation

Summary The effect of ion-supplemented medium on peroxidase excretion from horseradish (Armoracia rusticana) hairy roots was studied. Supplementation of mannitol instead of ions revealed that the excretion was stimulated not by osmotic pressure in the medium but by ionic properties. Extracellular peroxidase activity per dry cell was proportionally correlated with the ionic strength of the cations. CaCl₂ or MgCl₂ was found to be the most effective agent for excretion among other combinations. CaCl₂ supplementation at the beginning of the culture caused higher peroxidase production in the medium without a significant loss of final cell mass compared with CaCl₂ addition during the culture. Repeated batch culture with 50 mM CaCl₂ supplementation allowed a continuous retention of cell viability over 149 days and produced a great amount of extracellular peroxidase, 12-fold higher than that achieved in a 40-day-old batch culture with 50 mM CaCl₂ supplementation. Correspondence to: T. Kobayashi     

Flow cytometric analysis of oxidative burst of phagocytes with small amount of peripheral blood

We have developed a simple method for assessing the oxidative metabolic burst of peripheral blood leukocytes with a minute amount of whole peripheral blood by flow cytometry according to the method of Bass et al. with some modification. By this method, we can measure the H2O2 production by both granulocytes and monocytes in the same blood sample. The oxidative product formation by peripheral blood neutrophils can be monitored sequentially in the same mouse infected with E. coli. The mice infected intravenously with 0.1 LD50 of the bacteria showed increased basal activities from an early stage of infection; those infected intraperitoneally with the same dose of the bacteria showed a delayed enhancement. In case of infection with 0.01 LD50, the enhanced basal activities lasted for only a short period of time. The H2O2 production was correlated well with the clearance of the infected bacteria. These results demonstrated that the oxidative-product formation by peripheral blood neutrophils is affected by both the route and the dose of infection.     

Semisynthesis and properties of some insulin analogs

The trypsin-catalyzed coupling of bovine (Boc)₂-desoctapeptide (B23-B30)-insulin with synthetic octapeptides, H-Gly-X₂-X₃-X₄-Thr-Pro-Lys(Boc)-Thr-OH (X₂ = Phe or Ala, X₃ = Phe or Ala, X₄ = Tyr or Ala), followed by deprotection and purification produced the [Ala^B24, Thr^B30]-, [Ala^B25, Thr^B30]-, and [Ala^B26, Thr^B30]-analogs of bovine insulin in yields of 32, 35, and 32%, respectively. The biological activity of these analogs decreased in the order, normal insulin ([Thr^B30]-bovine insulin) = Ala^B26-insulin > Ala^B25-insulin > Ala^B24-insulin, as assayed for receptor binding and some other biological effects, in contrast with the corresponding Leu-analogs of human insulin, in which the activity decreased in the order, normal insulin > Leu^B24-insulin > Leu^B25-insulin. The affinity to insulin antibodies greatly diminished in both Ala^B24-insulin and Leu^B24-insulin but not in the B25-substituted analogs. The CD spectra of the Leu- and the Ala-analogs were compared with those of normal insulins to show that no apparent correlation seems to exist between the decrease in biological activity and the conformational changes observed in solution. The effects of organic solvents on the peptide-bond equilibrium and on the stability of trypsin are also discussed.     

A high-potential nonheme iron protein (HiPIP)-linked,thiosulfate-oxidizing enzyme derived fromChromatium vinosum

A thiosulfate-oxidizing enzyme was partially purified fromChromatium vinosum, and some of its properties were studied. The enzyme rapidly reducede HiPIP (high-potential nonheme iron protein) in the presence of thiosulfate. Cytochromesc of yeast and tuna and ferricyanide also acted well as electron acceptors for the enzyme; horse cytochromec was a poor electron acceptor. Cytochromec-552, cytochromec′, and cytochromec-553 did not act as electron acceptors. The enzyme was inhibited by cyanide and sulfite. On the basis of the stoichiometry in reduction of ferricyanide catalyzed by the enzyme in the presence of thiosulfate, the oxidized product of thiosulfate was inferred to be tetrathionate.     

Setup accuracy and dose attenuation of a wooden immobilization system for lung stereotactic body radiotherapy

BackgroundWe evaluated the setup error and dose absorption of an immobilization system with a shell and wooden baseplate (SW) for lung stereotactic body radiotherapy (SBRT).Materials and methodsSetup errors in 109 patients immobilized with an SW or BodyFix system (BF) were compared. Dose attenuation rates of materials for baseplates were measured with an ion-chamber. Ionization measurements were performed from 90° to 180° gantry angle in 10° increments, with the ball water equivalent phantom placed at the center of the wood and carbon baseplates whose effects on dose distribution were compared using an electron portal imaging device.ResultsThe ratio for the anterior-posterior, cranial-caudal, and right-left of the cases within 3-mm registered shifts in interfractional setup error were 90.9%, 89.2%, and 97.4% for the SW, and 93.2%, 91.6%, and 98.0% for the BF, respectively. For intrafractional setup error, 98.3%, 97.4%, and 99.1% for the SW and 96.6%, 95.8%, and 98.7% for the BF were within 3-mm registered shifts, respectively. In the center position, the average (minimum/maximum) dose attenuation rates from 90° to 180° for the wooden and carbon baseplates were 0.5 (0.1/2.8)% and 1.0 (–0.1/10.1)% with 6 MV, respectively. The gamma passing rates of 2%/2 mm for the wooden and carbon baseplates were 99.7% and 98.3% (p < 0.01).ConclusionsThe immobilization system with an SW is effective for lung SBRT since it is comparable to the BF in setup accuracy. Moreover, the wooden baseplate had lower radiation attenuation rates and affected the dose distribution less than the carbon baseplate.     

cis-Elements involved in expression of unspliced RNA in Moloney murine leukemia virus.

Murine leukemia virus (MLV) produces the unspliced RNA and the singly spliced RNA at a proper ratio at a time. To identify cis-elements involved in the production of the unspliced RNA, we examined the level of unspliced RNA in a series of mutants derived from a prototype Moloney MLV mutant gag-encoding G3.6. Our present data indicated that nt 1560-1906 region in the CA-encoding region in gag was the negative cis-element and nt 5119-5355 region, which was immediately upstream of the splice acceptor site, was the positive cis-element for expression of the unspliced RNA. It was found that the former element made expression of the unspliced RNA dependent upon the latter. These two elements were functional as discrete elements and their activities were relatively position-independent.     

Intracellular responses of antennal chordotonal sensilla of the American cockroach

The responses of mechanoreceptor neurons in the antennal chordotonal organ have been examined in cockroaches by intracellular recording methods. The chordotonal organ was mechanically stimulated by sinusoidal movement of the flagellum. Stimulus frequencies were varied between 0.5 and 150 Hz. Receptor neurons responded with spike discharges to mechanical stimulation, and were classed into two groups from plots of their average spike frequencies against stimulus frequency. Neurons in one group responded to stimulation over a wide frequency range (from 0.5 to 150 Hz), whereas those in a second group were tuned to higher frequency stimuli. The peak stimulus frequency at which receptor neurons showed maximum responses differed from cell to cell. Some had a peak response at a stimulus frequency given in the present study (from 0.5 to 150 Hz), whereas others were assumed to have peak responses beyond the highest stimulus frequency examined. The timing for the initiation of spikes or of a burst of spikes plotted against each stimulus cycle revealed that spike generation was phase-locked in most cells. Some cells showed phase-independent discharges to stimulation at lower frequency, but increasing stimulus frequencies spike initiation began to assemble at a given phase of the stimulus cycle. The response patterns observed are discussed in relation to the primary process of mechanoreception of the chordotonal organ.     

Quantitative structure–activity relationship analysis using deep learning based on a novel molecular image input technique

Quantitative structure–activity relationship (QSAR) analysis uses structural, quantum chemical, and physicochemical features calculated from molecular geometry as explanatory variables predicting physiological activity. Recently, deep learning based on advanced artificial neural networks has demonstrated excellent performance in the discipline of QSAR research. While it has properties of feature representation learning that directly calculate feature values from molecular structure, the use of this potential function is limited in QSAR modeling. The present study applied this function of feature representation learning to QSAR analysis by incorporating 360° images of molecular conformations into deep learning. Accordingly, I successfully constructed a highly versatile identification model for chemical compounds that induce mitochondrial membrane potential disruption with the external validation area under the receiver operating characteristic curve of ≥0.9.