Primary structure of the alpha-subunit of vacuolar-type Na(+)-ATPase in Enterococcus hirae. Amplification of a 1000-bp fragment by polymerase chain reaction.

A 1000-bp fragment of Enterococcus hirae genomic DNA was amplified by the polymerase chain reaction method, using the oligonucleotide primers designed from amino acid sequences of both amino-terminal and a tryptic fragment of the Na(+)-ATPase alpha-subunit in this organism. DNA sequencing of this product revealed that the amino acid sequence of Na(+)-ATPase alpha-subunit is highly homologous to the corresponding sequences of large (alpha) subunits of vacuolar (archaebacterial) type H(+)-ATPases, supporting our proposal [Kakinuma, Y. and Igarashi, K. (1990) FEBS Lett. 271, 97-101] that the Na(+)-ATPase of this organism belongs to the vacuolar-type ATPase.     

Gene organization deduced from the complete sequence of liverwort Marchantia polymorpha mitochondrial DNA. A primitive form of plant mitochondrial genome.

Analysis of the mitochondrial DNA of a liverwort Marchantia polymorpha by electron microscopy and restriction endonuclease mapping indicated that the liverwort mitochondrial genome was a single circular molecule of about 184,400 base-pairs. We have determined the complete sequence of the liverwort mitochondrial DNA and detected 94 possible genes in the sequence of 186,608 base-pairs. These included genes for three species of ribosomal RNA, 29 genes for 27 species of transfer RNA and 30 open reading frames (ORFs) for functionally known proteins (16 ribosomal proteins, 3 subunits of H(+)-ATPase, 3 subunits of cytochrome c oxidase, apocytochrome b protein and 7 subunits of NADH ubiquinone oxidoreductase). Three ORFs showed similarity to ORFs of unknown function in the mitochondrial genomes of other organisms. Furthermore, 29 ORFs were predicted as possible genes by using the index of G + C content in first, second and third letters of codons (42.0 +/- 10.9%, 37.0 +/- 13.2% and 26.4 +/- 9.4%, respectively) obtained from the codon usages of identified liverwort genes. To date, 32 introns belonging to either group I or group II intron have been found in the coding regions of 17 genes including ribosomal RNA genes (rrn18 and rrn26), a transfer RNA gene (trnS) and a pseudogene (psi nad7). RNA editing was apparently lacking in liverwort mitochondria since the nucleotide sequences of the liverwort mitochondrial DNA were well-conserved at the DNA level.     

Effect of 24,25-dihydroxyvitamin D3 in osteoclasts.

Previous results demonstrated that the administration of pharmacological doses of 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) to animals reduces bone resorption and increases bone volume with a decrease in osteoclast number. In order to clarify whether 24,25(OH)2D3 has an effect to inhibit osteoclastic bone resorption, the effect of 24,25(OH)2D3 on the formation and function of osteoclastic cells was examined in vitro. Treatment of hemopoietic blast cells, which are progenitors of osteoclasts, with parathyroid hormone (PTH) or 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) stimulated the formation of osteoclast-like multinucleated cells in a dose-dependent manner. Although 24,25(OH)2D3 in itself had little effect on osteoclast-like multinucleated cells formation, it inhibited the stimulatory effect of PTH on the formation of osteoclastic cells. In addition, 24,25(OH)2D3 also inhibited the stimulation of resorption pit formation by osteoclasts under stimulation with PTH. In contrast, 1,25(OH)2D3 stimulated the formation and function of osteoclastic cells even at low concentrations, and the effect was additive to PTH. These results could not be explained by either an agonistic or antagonistic effect of 24,25(OH)2D3 on 1,25(OH)2D3, and are consistent with the assumption that 24,25(OH)2D3 has a unique inhibitory effect on the formation and function of osteoclasts. Because 24,25(OH)2D3 is shown to stimulate the degradation of 1,25(OH)2D3 and because the formation of 24,25(OH)2D3 is stimulated by 1,25(OH)2D3 not only in the kidney but also in many of its target tissues, including bone, the inhibitory effect of 24,25(OH)2D3 on osteoclastic bone resorption may play a role in the local modulation of the actions of osteotropic hormones in bone.     

Biosynthesis of Xyloglucan in Suspension-Cultured Soybean Cells. Synthesis of Xyloglucan from UDP-Glucose and UDP-Xylose in the Cell-Free System

When UDP-[¹⁴C]glucose or UDP-[¹⁴C]xylose was incubated witha particulate fraction from soybean cells, radioactive polymerswere synthesized. On digestion with Aspergillus oryzae enzymes,these polymers gave ¹⁴C-monosaccharides and a ¹⁴C-disaccharidewith chromatographic and electrophoretic mobilities indistinguishablefrom those of authentic isoprimeverose (6-O--D-xylopyranosyl-D-glucopyranose).The disaccharide consisted of xylose and glucose, and the latterwas located at the reducing end. Evidence that the disaccharideis isoprimeverose was provided by methylation analysis. Hydrolysisof the methylated disaccharide yielded 2,3,4-tri-O-methyl-D-xyloseand 2,3,4-tri-O-methyl-D-glucose. Thus, incorporation of radioactivityinto isoprimeverose, the smallest structural unit of xyloglucan,suggests that xyloglucan is synthesized in vitro from UDP-glucoseand UDP-xylose. (Received November 20, 1980; Accepted February 14, 1981)     

Biosynthesis of Xyloglucan in Suspension-cultured Soybean Cells. Evidence that the Enzyme System of Xyloglucan Synthesis does not Contain {beta}-1,4-Glucan 4-{beta}-D-Glucosyltransferase Activity (EC 2.4.1.12)

Xyloglucan 4-ß-D-glucosyltransferase, an enzyme responsiblefor the formation of the xyloglucan backbone, in a particulatepreparation of soybean cells has been compared with ß-1,4-glucan4-ß-D-glucosyltransferase of the same origin. Thefollowing observations indicate that the enzyme system of xyloglucansynthesis does not contain ß-1,4-glucan 4-ß-D-glucosyltransferaseactivity, although both enzymes transfer the glucosyl residuefrom UDP-glucose to form the ß-1,4-glucosidic linkage:1. The incorporation of [¹⁴C]glucose into xyloglucan dependedon the presence of UDP-xylose in the incubation mixture. 2.No measurable amount of radioactivity was incorporated fromUDP-[¹⁴C]xylose into the cello-oligosaccharides, although theincorporation of [¹⁴C]xylose into xyloglucan depended on thepresence of UDP-glucose in the incubation mixture (Hayashi andMatsuda 1981b). 3. The activity of xyloglucan 4-ß-D-glucosyltransferasewas stimulated more strongly by Mn²⁺ than by Mg²⁺, whereas Mg²⁺was the most active stimulator for the activity of ß-1,4-glucan4-ß-D-glucosyltransferase. 4. An addition of GDP-glucose(100 µM) to the incubation mixture inhibited the activityof xyloglucan 4-ß-D-glucosyltransferase by 17%, whereasthe activity of ß-1,4-glucan 4-ß-D-glucosyltransferasewas inhibited 56% under the same conditions. 5. Irpex exo-cellulasedid not hydrolyze the xyloglucan synthesized in vitro. 6. Theß-1,4-glucan synthesized in vitro was not a branchedxyloglucan because it gave no 2,3-di-O-methyl glucose derivativeon methylation analysis. 7. Pulse-chase experiments indicatedthat the ß-1,4-glucan was not transformed into thexyloglucan. The subcellular distribution of the xyloglucan synthase, however,was similar to that of the ß-1,4-glucan synthase (Golgi-located1,4-ß-D-glucan 4-ß-D-glucosyltransferase).Thus, it appears that the latter enzyme is located at a siteclose to xyloglucan synthase and is set aside for the assemblyof these polysaccharides into the plant cell surface. (Received May 21, 1981; Accepted October 13, 1981)     

Degradation of Xyloglucan by Wall-bound Enzymes from Soybean Tissue I. Occurrence of Xyloglucan-degrading Enzymes in Soybean Cell Wall

An enzyme preparation that catalyzes the degradation of xyloglucanwas obtained by extraction of the cell walls of soybean hypocotylswith a buffer containing 1.0 M NaCl. The enzyme preparationwas shown to catalyze two-step degradation of xyloglucan. Thepolysaccharide was first degraded into comparatively large fragments,which were then further degraded into monosaccharides. In orderto elucidate the mode of degradation of the xyloglucan duringcell growth, the activities of xyloglucandegrading enzymes ofsoybean-hypocotyl segments were assayed at different stagesof elongation. The total activities of the degrading enzymeswere lower in the elongating regions than in the non-elongatingregions. However, high levels of endo-ß-l,4-glucanasewere found in the elongating regions. These results suggestthat xyloglucan is hydrolyzed by endo-ß-1,4-glucanaseinto comparatively large fragments at the initial stage of growthand the resulting fragments are further degraded into monosaccharidesduring cell elongation. (Received May 20, 1981; Accepted August 8, 1981)     

A Geometry-Based Multiple Testing Correction for Contingency Tables by Truncated Normal Distribution

Statistics in Biosciences - Inference procedure is a critical step of experimental researches to draw scientific conclusions especially in multiple testing. The false positive rate increases unless...     

Intrapopulation genetic variation in the level and rhythm of daily activity in Drosophila immigrans

Genetic diversity within a population, such as polymorphisms and personality, is considered to improve population performance because such intraspecific variations have the potential to alleviate the competition for a limited resource or the risk of predation and sexual harassment at a population level. Variation in the level and rhythm of daily activity in a population could also affect population performance by directly altering ecological, social, and sexual interactions among individuals. However, it remains to be elucidated whether such intra‐population variation in the level and rhythms of daily activity exists in a natural population. Here, we investigated the genetic variation in daily activity within a single natural population of Drosophila immigrans. We established 21 isofemale lines from a single natural population and measured larval activity level and the level and daily pattern of adult activity over a 24 hr period. Larval activity level significantly varied among isofemale lines. Likewise, the activity level in the adult stage significantly varied among lines. The significant variation was also found in the daily pattern of adult activity; some lines showed greater activity level in the daytime, and others showed greater activity level in the night. Our results consistently suggest that there is a genetic variation in behavioral activity in a natural population, probably contributing to shaping the population performance.     

Effects of caffeine on mating behavior and sperm precedence in Tribolium castaneum

Biogenic amines such as dopamine are physiologically neuroactive substances that affect behavioral and physiological traits in invertebrates, and it has long been known that these substances affect mating behavior in insects. Caffeine is a dopamine activator and thus enhances dopamine receptor activity. However, the effects of caffeine intake on insect mating behavior have been largely unexplored. Therefore, we examined the effect of caffeine on mating behavior in the red flour beetle Tribolium castaneum. Caffeine, which activates dopamine, affected the mating behavior of T. castaneum males. Males who orally ingested caffeine courted faster than males who did not, resulting in faster mounting of females and less time to a male's external aedeagus protrusion. However, the present results showed no difference in sperm precedence measured as a P2 value between males fed caffeine and males not fed caffeine. We discuss the effects of caffeine on insect mating and the possibility that caffeine consumption may cause males to mate with more females in the laboratory.