Electron microscope studies on the vegetative cellular life cycle of Chlamydomonas reinhardi Dangeard in synchronous culture I. Some characteristics of changes in subcellular structures during the cell cycle, especially in formation of giant mitochondria

Changes in subcellular structures during the entire vegetativecell cycle of Chlamydomonas reinhardi Dangeard in synchronousculture were followed with an electron microscope. Giant mitochondriaof various shapes were temporarily formed, probably by fusionof smaller mitochondria, in the algal cells at an intermediatestage of the growth phase of the cell cycle. Formation of giantmitochondria was accompanied by a marked decrease in the oxygen-uptakeactivity of cells. Giant mitochondria divided into smaller formsconcurrently with a re-increase in the oxygen-uptake activityof cells. Some characteristics of changes in the structuresof chloroplast, the nucleus, the endoplasmic reticula, flagellaand dictyosomes are described. ¹ This work was reported in part at the 35th Annual Meetingof the Botanical Society of Japan, October 1970. (Received October 13, 1971; )     

Fractionation of chromosomal proteins of pea seedlings using procedures which avoid denaturation

Chromatin was prepared from the buds and cotyledons of Alaskapea seedlings. The dissociated chromosomal components in thepresence of 2 M NaCl and 5 M urea were completely fractionatedinto DNA and proteins with a Bio-Gel A50 column. The proteinswere recovered by (NH₄)₂SO₄ and further fractionated into histonesand non-histone proteins using a Bio-Rex 70(Na⁺) column. Thedifference in the ratios of histones to non-histone proteinsbefore and after chromatography with the Bio-Rex 70 was lessthan 10%. The histones and non-histone proteins thus preparedshowed typical protein absorption spectra. Polyacrylamide gelelectrophoresis of histones showed that the histone compositionsin buds and cotyledon were similar, but the amount of HI histoneswas a little less in cotyledons than in buds. Unlike histones,non-histone proteins fractionated by SDS-polyacrylamide gelelectrophoresis indicated distinct differences between the twotissues. Buds had more heterogeneous non-histone proteins, atleast 13 polypeptides, than cotyledons did. On the other hand,non-histone proteins of cotyledons showed less heterogeneityand lacked proteins of high molecular weight which were foundin buds. (Received May 6, 1976; )     

Anterograde Axonal Transport of Peptidylglycine α-Amidating Monooxygenase in Rat Sciatic Nerves

Axonal transport of peptidylglycine alpha-amidating monooxygenase (PAM) activity was studied in rat sciatic nerves from 12 to 120 h after double ligations. The anterograde axonal transport increased and reached a plateau between 48 and 72 h and then decreased. The flow rate was 100 mm/day, and the molecular mass of the active entity was 70 kDa, which was determined by gel filtration. In contrast, there was no evidence for significant retrograde axonal transport. Anterograde axonal transport of immunoreactive cholecystokinin, a carboxy-terminal-amidated putative neuropeptide, was also found. These results suggest that PAM is transported by a rapid axonal flow and may play a role as a processing enzyme during transport or in the terminals of rat sciatic nerves.     

The molecular analysis ofbrown eye color mutations isolated from geographically discrete populations ofDrosophila melanogaster

A large proportion of spontaneous mutations inDrosophila melanogaster strains of laboratory origin are associated with insertions of mobile DNA elements. As a first step toward determining whether spontaneous laboratory mutations are predictive for mutational events occurring in the wild, recessivebrown (bw) eye color mutants were isolated. By inbreeding the progeny of wild-caughtDrosophila melanogaster females,bw mutations were isolated from seven separate geographic sites distributed among Japan, California, Siberia and Hungary. Among a total of 14 mutations studied, no case of transposon mutagenesis was found. At least 4 mutations are associated with small deletions in thebw gene. The remainder are inseparable from wild-typebw by Southern analysis and are presumed to be basepair changes or very small indels. Although only two spontaneousbw mutants of laboratory origin have been analyzed molecularly, one is a mobile element insertion.     

Enhancing effects of CO2 on chloroplast regeneration in glucose-bleached cells of Chlorella protothecoides I. Role of non-photosynthetic CO2-fixation in chloroplast regeneration

Carbon dioxide enhanced chloroplast regeneration in glucose-bleachedcells of Chlorella protothecoides in the presence of CMU inthe light. Both the formation of chlorophyll and the synthesesof RNA and protein were considerably enhanced. The CO₂ metabolism of algal cells during greening was investigatedusing ¹⁴C-bicarbonate as the tracer. Radiocarbon was largelyincorporated into purine and pyrimidine bases in nucleic acidand the arginine in protein, specifically at the crabon atomsderived from carbamylphosphate. ¹Part of this investigation was reported at the conference onthe "Autonomy and biogenesis of mitochondria and chloroplasts"held at Canberra in 1969 (4). (Received August 19, 1975; )     

Tamarindus indica L. leaf is a source of allelopathic substance

The allelopathic potential of the Tamarindus indica L. leaf was investigated through bioassay guided studies using several weed and edible crop species. Both radicle and hypocotyl growth of all the plant species tested was strongly inhibited by the tamarind leaf using a sandwich method. The growth of weed species was reduced more than that of edible crop species. Among the weed species, barnyard grass followed by white clover, and in the edible crop species, lettuce followed by radish ranked top in terms of growth inhibition. Different concentrations of tamarind leaf crude water-soluble extract exhibited a strong inhibition in all the plant species tested and, by contrast, the magnitude of inhibition in the weed species was higher than in edible crop species and ranged from 30–75%. The 10% concentration of the tamarind leaf crude water-soluble extract was most potent against growth of seedlings. The concentrations of the nutrient components were linearly correlated with an increase in the concentration of tamarind leaf crude water-soluble extract. No significant changes in either pH or EC were found in the variations of different concentrations of tamarind leaf crude water-soluble extracts. As compared to control, growth of both radicle and hypocotyl in weed (barnyard grass and white clover) and in edible crop (lettuce and radish) species were significantly reduced when blended tamarind leaves at different concentrations were incorporated into the growth medium. The inhibitory magnitude increased with an increase in the concentration of the tamarind leaf. In terms of growth inhibition, among these tested plants, weed species particularly barnyard grass were most sensitive to the allelochemicals exuded from blended tamarind leaves. When the blended tamarind leaves were removed from the growth medium, all the seedlings grew quickly and the percentage of recovery was between 76–97% of the corresponding controls. Reduction in the fresh and dry weight of these 4 plant species was observed under the experimental conditions, and ranged between 33–42% and 40–53% in the radicle and hypocotyl, respectively. The fresh and dry weight, and total chlorophyll content declined significantly in the incorporated tamarind leaf treatments. Compared to the control, the highest drop in the chlorophyll content of 60% in barnyard grass was observed with the 10% concentration of the leaf treatment. These results clearly indicate that the tamarind leaf contains one or more strong biologically active allelochemical(s) that function as true growth regulator(s) and is involved in plant growth regulation, particularly in weed species.     

Risk factors for bone loss in patients with rheumatoid arthritis treated with biologic disease-modifying anti-rheumatic drugs

Objective

Osteoporosis is a complication of rheumatoid arthritis. We examined the risk factors for bone loss in rheumatoid arthritis patients receiving biological disease-modifying anti-rheumatic drugs. Lumbar spine and femoral neck bone mineral density was measured at two time points in 153 patients with rheumatoid arthritis managed with biological disease-modifying anti-rheumatic drugs. We examined patients’ variables to identify risk factors for least significant reduction of bone mineral density.

Results

Least significant reduction of lumbar spine bone mineral density (≤ ? 2.4%) was seen in 13.1% of patients. Least significant reduction of femoral neck bone mineral density (≤ ? 1.9%) was seen in 34.0% of patients. Multiple logistic regression analysis showed that a risk factor for least significant reduction of the lumbar spine was high-dose methylprednisolone use. Multiple regression analysis showed that a risk factor for least significant reduction of the femoral neck was short disease duration. Our findings showed that a risk factor for femoral neck bone mineral density reduction was a short disease duration. These findings suggest that rheumatoid arthritis patients receiving treatment with biological disease-modifying anti-rheumatic drugs may benefit from earlier osteoporosis treatments to prevent femoral neck bone loss.

     

Simultaneous determination of citalopram and its metabolites by high-performance liquid chromatography with column switching and fluorescence detection by direct plasma injection

High-performance liquid chromatography with a successive column-switching technique was developed for simultaneous determination of citalopram and its four metabolites in plasma. Plasma samples were injected directly, and the target compounds were purified and concentrated with an inexpensive commercial octadecyl guard column. Then, the six-port valve was switched, and the compounds retained in the column were eluted by the back-flush method using 20 mM phosphate buffer (pH 4.6)-acetonitrile (70:30, v/v) containing 0.1% diethylamine and separated with an ODS column. The compounds were assayed with a fluorescence detector at an excitation wavelength of 249 nm and an emission wavelength of 302 nm. At least 30 plasma samples could be treated with an octadecyl guard column. The limits of quantitation of this method were 2.0 ng/ml for citalopram, desmethylcitalopram, didesmethylcitalopram, citalopram propionic acid and citalopram N-oxide. This method was applied to a pharmacokinetic study in dogs and a toxicokinetic study in rats.