Changes of aldolase A and B messenger RNA levels in rat liver during azo-dye-induced hepatocarcinogenesis

The expression of aldolase A and B mRNAs during azo-dye-induced carcinogenesis in rat liver was examined. After feeding the dye for 18 weeks, the level of aldolase A mRNA increased to about 11 times that in a normal liver, with the concomitant decrease of aldolase B mRNA level to about 25% of that in a normal liver. These changes did not occur progressively during the carcinogenesis, but occurred as an additional phase after 4 week-feeding of the azo-dye. At this stage, the levels of aldolase A and B mRNAs were about 7 times and 45% of that in a normal liver, respectively. This biphasic pattern in the aldolase isozyme expression in the azo-dye-fed rat liver is discussed together with the kinetic data of the enzyme activity.     

Diazepam action onγ-aminobutyric acid-activated chloride currents in internally perfused frog sensory neurons

The Cl- current (ICl) in gamma-aminobutyric acid (GABA)-sensitive frog sensory neuron was separated from other Na+, Ca2+, and K+ currents using a suction pipette technique which allows internal perfusion under a single-electrode voltage clamp. Diazepam (DZP) itself evoked no response but facilitated the dose- and time-dependently GABA-induced ICl without changing the GABA equilibrium potential (EGABA) at concentrations ranging widely, from 3 X 10(-9) to 10(-4) M. In the presence of DZP, the GABA dose-response curve shifted to the left without changing the maximum current, indicating that DZP modifies the interaction between GABA and its receptor rather than affecting directly the channel activation step. The enhancement of the GABA-induced ICl by DZP depended neither on the membrane voltage nor on the inward or outward direction of the ICl. DZP also potentiated the ICl elicited by GABA agonists such as beta-alanine, taurine, homotaurine, 5-aminovaleric acid, l-GABOB, d-GABOB, glycine, and muscimol. The GABA response enhanced by pentobarbital (PB) was further enhanced by adding DZP, indicating that DZP and PB do not act in the same way. Ro5-3663, a diazepam analogue, enhanced the GABA-induced ICl only in a narrow range of the concentrations but inhibited the current at concentrations higher than 2 X 10(-6) M.     

Chloroplast division in cultured cells of the hornwortAnthoceros punctatus

Using cultured cells of the hornwortAnthoceros punctatus, the change in the relative chloroplast DNA content in each stage of chloroplast division was investigated to clarify the relationship between the division cycle of a chloroplast and a cell nucleus. Samples of cultured cells were stained with 4′,6-diamidino-2-phenylindole (DAPI) and then observed with an epifluorescence microscope and a chromosome image analyzing system (CHIAS). A chloropiast in cultured cells duplicated DNA with an increase in size. When a chloroplast began to divide, it was constricted in the middle, taking a dumbbell shape, and then divided into two daughter chloroplasts. In cultured cells of this species, the pattern of quantitative change of chloroplast DNA, that is, the DNA replication pattern of chloroplasts, corresponded to that of cell nuclear DNA in mitosis.     

Chromatin arrangements in intact interphase nuclei examined by laser confocal microscopy

Using a laser confocal microscope, chromatin arrangements in intact interphase nuclei were investigated in four plant species. Chromosomes in these plants have specific segments that can be stained with the fluorescent dye chromomycin A₃ (CMA). We stained centromeres inHordeum vulgare, sub-telomeric regions inSecale cereale, satellites inChrysanthemum multicore, and the satellites and the short arms of chromosomes with satellites inHemerocallis middendorfii. The following points were shown: (1) In mitotic interphase nuclei, the centromere and the telomeres of both arms touched the nuclear membrane and had evident polarity. Some CMA-bodies in sub-telomeric regions do not contact the nuclear membrane. (2) Differentiated nuclei had a non-random construction. Polarity of chromosomes is maintained, however, the chromosomes are far apart from the nuclear membrane. (3) Associations in sub-telomeric regions in the interphase nuclei ofSecale cereale were probably due to the association of heterochromatic regions with identical repeated sequences rather than telomere associlations. (4) In interphase nuclei ofChrysanthemum multicore, satellites fused during interphase.     

An anchorage-dependent locus in the cell cycle for the growth of 3T3 cells

Mouse fibroblasts, 3T3 cells, require a solid surface for continuous growth, but when 3T3 cells, during their exponential phase in Petri dishes, were transferred to a suspension culture, the number of cells roughly doubled by 30 h. During the suspension culture the number of pairing cells (c₂) increased, but that of the single cells decreased. When cells synchronized at mitosis or at the G1-S boundary were transferred to the suspension culture, the number of pairing cells peaked at 30 min and at 10 h, respectively. DNA synthesis began immediately after the cells, which were cultured for 16 h in the suspension, had settled onto the surface of the Petri dishes. When cells in a confluent culture were arrested at an early G1 period and were suspended, the number of pairing cells did not increase. These results indicate that the most important locus for anchorage growth seems to be at a late G1 period of the cell cycle.     

Population abundance gradient of Inurois punctigera along altitude

A winter geometrid moth, Inurois punctigera, shows sympatric and genetically isolated seasonal populations (i.e. early‐ and late‐winter populations) in the cold regions of Japan, whereas it shows only mid‐winter populations in the warm regions. Variation in adult flight phenology on a large geographic scale along latitudinal environmental gradients has been described, but the phenological variation on a more local scale along altitudinal environmental gradients has not yet been characterized. In the present study, we assessed the flight phenology at high‐ and low‐elevation areas in Mt. Rokko, Hyogo, Japan. First, we revealed that flight period was not disrupted in mid‐winter, even at high‐elevation areas (>660 m) but the population abundance was much lower in high‐elevation areas than in low‐elevation areas. Then, in the following two seasons, we investigated I. punctigera abundance, winter harshness (i.e. winter temperature) and their host plant abundance in nine closely located stations in Mt. Rokko. A generalized linear mixed model analysis indicated a greater effect of winter temperature on I. punctigera abundance compared to available food resources, suggesting that differences in winter harshness among elevation shapes the gradient of I. punctigera abundance along altitude. Our findings suggest that harsh conditions during winter function as selective agents on mid‐winter types of I. punctigera, and this could be involved in the divergence between sympatric early‐ and late‐winter populations of I. punctigera.     

Skeletal FGFR1 signaling is necessary for regulation of serum phosphate level by FGF23 and normal life span

Fibroblast growth factor (FGF) 23 produced by the bone is the principal hormone to regulate serum phosphate level. Serum FGF23 needs to be tightly regulated to maintain serum phosphate in a narrow range. Thus, we hypothesized that the bone has some phosphate-sensing mechanism to regulate the production of FGF23. Previously we showed that extracellular phosphate induces the phosphorylation of FGF receptor 1 (FGFR1) and FGFR1 signaling regulates the expression of Galnt3, whose product works to increase FGF23 production in vitro. In this study, we show the significance of FGFR1 in the regulated FGF23 production and serum phosphate level in vivo. We generated late-osteoblast/osteocyte-specific Fgfr1-knockout mice (Fgfr1^fl/fl; Ocn^Cre/+) by crossing the Ocn-Cre and the floxed Fgfr1 mouse lines. We evaluated serum phosphate and FGF23 levels, the expression of Galnt3 in the bone, the body weight and life span. A selective ablation of Fgfr1 aborted the increase of serum active full-length FGF23 and the enhanced expression of Galnt3 in the bone by a high phosphate diet. These mice showed more pronounced hyperphosphatemia compared with control mice. In addition, these mice fed with a control diet showed body weight loss after 23 weeks of age and shorter life span. These results reveal a novel significance of FGFR1 signaling in the phosphate metabolism and normal life span.     

Some Properties and Characterization of Rice Seed Hemagglutinin

The phytohemagglutinin of rice seed has been purified by a sequence of steps involving fractionation with ammonium sulfate and successive chromatography on DEAE-and eMcellulose and finally gel filtration on Bio-Gel P-100. The purified rice seed hemagglutinin was shown to be homogeneous by electrophoresis on polyacrylamide gel and its molecular weight was 10,000, calculated from both the Ve/Vo value of gel filtration on Bio-Gel P-100 and the sum of the individual constituents (amino acids, sugars and metals). In addition to amino acid, the rice seed hemagglutinin contained 26.8% covalently bound carbohydrate which was identified and quantitated by gas chromatography of the acetylated alditols. Glucose was the predominant sugar with lesser amounts of glucosamine, xylose, and mannose also being present. And the rice seed hemagglutinin contained 1 g atom of calcium per molecule. The molecular weight of the rice seed hemagglutinin is smallest compared with some of phytohemagglutinins isolated from leguminous seeds and other plant sources. The rice seed hemagglutinin has the blastogenetic activity for human peripheral lymphocytes as well as Phaseolus vulgaris phytohemagglutinins or concanavalin A, jack bean hemagglutinin.     

Studies on the Monoterpene Fraction of “Geranium Oil” from Pelargonium roseum Bourbon

Investigation has been carried out on the constituents of the monoterpene fraction of geranium oil from Pelargonium roseum Bourbon and, besides well-known components of the oil, some new components such as epoxylinalool, methyl heptenone, myrcene, limonene, p-cymene, citral and 2,2,6-trimethyl-6-vinyl-tetrahydropyran which was confirmed by deriving to cinenic acid, have been identified.     

Biochemical Studies during the Development of the Chick Embryo

The devised method consists of the enzymatic hydrolysis, separation of deoxyribosides in the hydrolysate by paper chromatography and paper electrophoresis, and the estimation of the separated fractions with L. leichmannii. This method permits the determination of deoxyriboside composition of the smaller amounts of DNA or the related compounds with relatively higher accuracy even under the presence of some other compounds when nucleic acids and acid insoluble fractions of the chick embryo were analyzed.

The change of each deoxyriboside composition in acid insoluble fraction prepared from the 3 to 19 day old embryos investigated by the method. Among the major four deoxyribosides, the contents of deoxyguanosine and of deoxycytidine was nearly constant during the development of the embryo, whereas that of thymidine and of deoxyadenosine appeared to undergo the change slightly at the periods from 10 to 15 days incubation. It seems that this periods is also the most active time of the synthesis of DNA and of the changes of deoxyribosyl compounds in acid soluble fraction through the embryo growth.