Polygalacturonase mRNA of Tomato: Size and Content in Ripe Fruits

In ripe tomato fruits, polygalacturonase (PG) mRNA comprisedabout 1% of the translatable RNAs in the poly(A)(+)RNA fraction.Sucrose density gradient centrifugation showed that this PGmRNA is similar in size to 18S rRNA, which suggests the presenceof a non-coding region. (Received June 19, 1984; Accepted October 23, 1984)     

Ancestral MADS box genes in Sugi, Cryptomeria japonica D. Don (Taxodiaceae), homologous to the B function genes in angiosperms.

In flowering plants, flower organ identity is controlled by the ABC genes, including several MADS box genes. We present two MADS box genes of a conifer, Cryptomeria japonica D. Don. The genes, CjMADS1 and CjMADS2, were related to the angiosperm B function genes which determine the identities of petals and stamens. A phylogenetic analysis showed that these genes form a new clade outside the angiosperm B group, that is, PISTILLATA (PI) and APETALA3 (AP3) lineages. CjMADS1 had a PI-group specific motif and CjMADS2 had AP3-group specific motifs at the C terminal end, respectively. CjMADS1 was expressed in male strobili (or cones) throughout its development, while CjMADS2 was transiently expressed during male strobilus development. The specific expression in the male reproductive organ indicated that the B function is maintained in gymnosperms. Our cladistic analysis suggests that the gene duplication event which generated B function gene lineages predates the divergence of angiosperms and gymnosperms and that the gene duplication which produced the two genes of C. japonica occurred in an ancestral conifer species.     

Role of afferent input in muscle atrophy.

It is well known that soleus muscle of rat atrophies following spaceflight or hindlimb suspension (Ohira et al., 1992). It is, further, reported that the electromyogram (EMG) of soleus muscle disappears immediately in response to unloading by exposure to actual micro-g environment (Kawano et al., 2002; Leterme and Falempin, 1998) and by hindlimb suspension of rats (Alford et al., 1987; Ohira et al., 2000). However, the EMG level is increased gradually to the control level following 7-10 days of continuous hindlimb suspension (Alford et al., 1987; Ohira, 2000), while muscle atrophy is progressing (Winiarski et al., 1987). We previously reported that reduction of the EMG level of rat soleus in response to actual micro-g environment, created by a parabolic flight of a jet airplane, was closely associated with a decrease of the afferent input recorded at the L5 segmental level of spinal cord (Kawano et al., 2002). However, it is still unclear how the EMG level of soleus muscle adapts to unloading condition. The current study was performed to investigate the responses of soleus EMG and both afferent and efferent neurogram at the L5 segmental level of spinal cord to acute (20 seconds) and chronic (14 days) unloading.     

Development and evaluation of intermediate frequency magnetic field exposure system for studies of in vitro biological effects

We have developed an intermediate frequency (IF) magnetic field exposure system for in vitro studies. Since there are no previous studies on exposure to heating-frequency magnetic fields generated from an induction heating (IH) cook top, there is a strong need for such an exposure system and for biological studies of IF magnetic fields. This system mainly consists of a magnetic-field-generating coil housed inside an incubator, inside which cultured cells can be exposed to magnetic field. Two systems were prepared to allow the experiment to be conducted in a double-blind manner. The level of the generated magnetic field was set to 532 microT rms in the exposure space, 23 kHz, 80 times the value in the International Commission on Non-ionizing Radiation Protection (ICNIRP) guidelines, with a spatial field uniformity better than 3.8%. The waveforms were nearly sinusoidal. It was also confirmed that the parasitic electric field was 157 V/m rms and the induced electric field was 1.9 V/m rms. The temperature was maintained at 36.5 +/- 0.5 degrees C for 2 h. Furthermore, leaked magnetic flux density was 0.7 microT rms or lower at extremely low frequency (ELF) and IF in the stopped system when the other system was being operated, and the environmental magnetic flux density was 0.1 microT rms or lower at the center of the coils. As a result, it was confirmed that this system could be successfully used to evaluate the biological effects of exposure to IF magnetic fields.     

A highly polar xanthophyll of 9′-cis-neoxanthin induces apoptosis in HCT116 human colon cancer cells through mitochondrial dysfunction

Highly polar xanthophylls of 9′-cis-neoxanthin (neoxanthin) and fucoxanthin, which have the characteristic structure of an epoxy group and an allenic bond, were previously found to induce apoptosis in human prostate cancer cells. In the present study, we found apoptosis induction by neoxanthin in HCT116 human colon cancer cells and examined the induction mechanism. The cells exposed to 20 μM neoxanthin clearly showed chromatin condensation, DNA fragmentation, and an increase in hypodiploid cells. Neoxanthin treatment increased the activities of caspase-3, -8 and -9, and the protein levels of their active subunits, except in the case of caspase-8. The treatment also caused the loss of mitochondrial transmembrane potential at an early stage and subsequently the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria to cytosol. The exposure of neoxanthin directly to mitochondria isolated from the cells enhanced the release of cytochrome c and AIF in a dose-dependent manner. Approximately 50% of the neoxanthin taken up into the HCT116 cells accumulated in the mitochondrial fraction. These results suggest that the accumulation of neoxanthin in mitochondria causes the loss of mitochondrial transmembrane potential and thereafter releases cytochrome c and AIF, leading to the execution of apoptosis.     

Constitutive over-expression of VEGF results in reduced expression of Hand-1 during cardiac development in Xenopus

During heart development, various signaling cascades are tightly regulated in a stage- and region-dependent manner. Vascular endothelial growth factor (VEGF) is one of the important molecules required for both vascular development and cardiac morphogenesis. VEGF receptors are present in the embryonic heart, so we focused on heart formation in VEGF-over-expressing Xenopus embryos. Over-expression of VEGF(170) caused disorganized vessels, while the expression of an endothelial marker, Tie-2, was increased. The embryo's heart was distinctly larger than that of control, and showed abnormal morphology. Histological analysis of these embryos showed failure of heart looping. In situ hybridization with Hand-1, which controls intrinsic morphogenetic pathways, revealed that the expression level of Hand-1 was decreased in the heart region. These results suggest that increased VEGF(170) levels disturb Hand-1 expression in the region required for normal heart morphogenesis. VEGF expression level may be important in heart morphology during embryonic development.     

Action of neltenexine on anion secretion in human airway epithelia

Neltenexine has been applied to human lung diseases such as chronic obstructive pulmonary disease (COPD) as a mucolytic agent. However, we have no information on the neltenexine action in bronchial epithelial cells. We studied the neltenexine action on the ion transport in human submucosal serous Calu-3 cells. Under a hyper-secreting condition caused by terbutaline (a beta2-adrenergic agonist), neltenexine diminished anion secretion by inhibiting the Cl- and HCO3- uptake via Na+/K+/2Cl- cotransporter and Na+/HCO3- cotransporter without blockade of the cystic fibrosis transmembrane conductance regulator (CFTR) channel, and also diminished anion secretion via stimulation of Cl-/HCO3- exchanger, which facilitates the extrusion of more CFTR-permeant anion, Cl-, with the uptake of less CFTR-permeant anion, HCO3-. Thus, neltenexine reduced the hyper-secretion to keep an appropriate fluid level in the airway, providing a possibility that neltenexine can be an effective drug in airway obstructive diseases by decreasing the airway resistance under a hyper-secreting condition.     

Synthesis and antibacterial activities of new quinolone derivatives utilizing 1-azabicyclo[1.1.0]butane

The ring-opening reactions of 1-azabicyclo[1.1.0]butane 3 with thiols 6a-f gave 3-sulfenylazetidine derivatives 7a-f in 50-92% yields. Treatment of 3 with aromatic amines 11a-e and dibenzylamine 11f in the presence of Mg(ClO(4))(2) afforded the corresponding 3-aminoazetidine derivatives 12a-f in 24-53% yields. These azetidine derivatives were introduced into the C7 position of a quinolone nucleus 8 to afford the corresponding fluoroquinolones 9a-f and 13a-f in 21-83% yields. Some of them exhibited superior antibacterial activity against quinolone-susceptible MRSA in comparison with clinically used fluoroquinolones, such as levofloxacin, ciprofloxacin, and gatifloxacin.