Detection of GST1 gene deletion by the polymerase chain reaction and its possible correlation with stomach cancer in Japanese

Summary A homozygous gene deletion at the GST1 locus of genomic DNA isolated from peripheral blood was investigated for its relationship with several types of cancer using the polymerase chain reaction (PCR) technique. DNA samples were prepared from blood obtained from 128 healthy blood donors and 150 patients with cancer or chronic hepatitis. PCR primers were prepared based on the human cDNA sequence and the intron/exon sequences of the rat Yb2 gene. The amplified sequence between exons 5 and 6 including intron 5 showed very clearly the presence of absence of the GST1 gene, after electrophoresis in a 2% agarose gel. Segregation of the presence and absence of PCR product from samples of twins and their parents indicated that presence involves homozygous or heterozygous normal GST1 genotypes while absence invovles only homozygous gene deletion. The patients with stomach cancer had a significantly higher frequency of gene deletion than did the healthy controls (P< 0.005). Thus, GST1 deletion may be a possible genetic marker for early detection of a group at high risk of stomach cancer.     

Effects of short-term treatment with calcium on the parathyroid glands in golden hamsters of different ages, with special reference to large vacuolar bodies.

The effects of different ages on large vacuolar bodies in the parathyroid glands of golden hamsters after short-term treatment with calcium were investigated. In the parathyroid glands of the young and adult animals 15 min and the senile animals 15 and 60 min after administration of calcium, the percent area occupied by large vacuolar bodies was significantly increased as compared to that of the young, adult and senile control animals, respectively. These findings suggest that the percent area occupied by large vacuolar bodies is increased in response to acute hypercalcemia. It is thought that in the parathyroid glands suppressed by hypercalcemia there is a relationship between the percent area occupied by large vacuolar bodies and aging.     

Pulsatile infusion of luteinizing hormone-releasing hormone induces precocious puberty (vaginal opening and first ovulation) in the immature female guinea pig

Previously we have hypothesized that an increase in luteinizing hormone-releasing hormone (LHRH) due to hypothalamic maturation is the key factor controlling the onset of puberty. This led to the working hypothesis that precocious puberty would be induced if LHRH is administered with an appropriate protocol. Thus, effects of pulsatile infusion of LHRH on the onset of first vaginal opening and first ovulation in immature female guinea pigs were studied. Luteinizing hormone-releasing hormone in hourly pulses of either 5 ng or 50 ng was infused through a chronically implanted jugular catheter for 9-29 days starting at 20 days of age. For the control experiment saline was infused in a similar manner. Infusion of 5 ng LHRH/h resulted in significantly earlier (P less than 0.001) ages at first vaginal opening (24.7 +/- 0.9 days) and at first ovulation (28.8 +/- 0.9 days) compared to saline controls (first vaginal opening 53.3 +/- 6.8 days; first ovulation 55.2 +/- 6.5 days). Infusion with a 10-fold higher LHRH dose (50 ng/h) also advanced the age at first vaginal opening (25.3 +/- 0.7 days), but precocious ovulation was no longer induced (53.7 +/- 5.3 days). Interestingly, LHRH infusion with the high dose resulted in a prolonged period of vaginal opening and cornification without ovulation. These results indicate that 1) pulsatile infusion of a small amount of LHRH with a constant frequency induces precocious puberty in a laboratory rodent, and 2) infusion of LHRH with a dose higher than the effective dose for the induction of early puberty results in a persistent estrous anovulatory syndrome. Therefore, the present study not only supports our hypothesis that an increase in endogenous LHRH release is responsible for the onset of puberty, but also further suggests that excessive release of LHRH or abnormal patterns of LHRH release may be involved in the etiology of the anovulatory persistent estrus syndrome.     

An apparent discrepancy between chain length and electrophoretic mobility of restriction fragments: a case of human mitochondrial DNA

Summary DNA sequence analysis and electrophoresis in denaturing gel revealed that a 60 base pair insertion which had been previously postulated on the basis of native polyacrylamide gel electrophoresis of mitochondrial DNA from Japanese (Horai and Matsunaga 1986) did not exist at all. Unusual behavior of certain restriction fragments in native polyacrylamide gels apparently resulted in what appeared to be an insertion. Further study revealed that this behavior is most likely due to secondary structures of the fragments. The results of the present study suggest that adequate care should be taken when assessing molecular weights of restriction fragments by native polyacrylamide gel electrophoresis.     

Adhesiveness of beta5 integrin variant lacking FNK767-769 is similar to that of the prototype containing FNKFNK764-769

Little is known about the functions of two different beta5 integrins: repeated-FNK (FNKFNK764-769) and single-FNK (FNK764-766) amino acid sequences in the cytoplasmic domain. We examined whether they occurred as germ line mutations or somatic mutations associated with neoplastic transformation, and whether there were functional alterations. Out of six cultured cell lines, only KATO-III cells had the single-FNK beta5 sequence. The single-FNK beta5 was found in 9 out of 79 patients with colon carcinoma, but no somatic mutations were detected in cancerous tissues. CHO cells were transformed with expression vectors containing single-FNK or repeated-FNK beta5 cDNA, which were derived from KATO-III cells. CHO cells transfected with single-FNK and repeated-FNK showed similar adhesiveness to, and proliferative activity on, vitronectin substrates.     

Diversity of dung-beetle community in declining Japanese subalpine forest caused by an increasing sika deer population

The Ohdaigahara subalpine plateau in Japan has recently suffered a reduction in primary forest land caused by an increasing population of sika deer (Cervus nippon). Deer have debarked many trees, causing dieback, gradually changing the primary forest first to light forest with a floor that is densely covered with sasa grass (Sasa nipponica) and then to S. nipponica grassland. To examine the effects of vegetative transformation on the dung-beetle community, we compared the diversity and abundance of dung-beetle assemblages in the primary forest, transition forest, and S. nipponica grassland using dung-baited pitfall traps. The species richness and species diversity (Shannon-Wiener index) were significantly highest in the primary forest and lowest in the S. nipponica grassland. The evenness (Smith-Wilson index) was highest in the primary forest and nearly equal in the transition forest and S. nipponica grassland. The abundance was apparently greater in the transition forest than in the primary forest and S. nipponica grassland. These results suggest that loss of primary forest resulting from an increasing deer population decreases the diversity of the dung-beetle community while increasing the abundance of dung beetles in the transition forest. Sika deer use transition forests and grasslands more frequently than primary forests as habitat, but an increase in dung supply there does not necessarily increase the diversity or abundance of dung-beetle assemblages.     

Induction of inducible nitric oxide (NO) synthase mRNA and NO production in macrophages infected with influenza A/PR/8 virus and stimulated with its ether-split product

We investigated the inductive activity of infective influenza A/PR/8/34 (PR8) virus and its ether-split product (ESP) on the expression of inducible nitric oxide (NO) synthase (iNOS) and NO production in RAW264.7 (RAW) cells, a murine macrophage (M psi) cell line, and thioglycolate-elicited peritoneal M psi (TPM). In both cells, PR8 virus infection induced iNOS mRNA between 4 hr and 24 hr, attaining a peak value at 12 hr. In correlation with induction of iNOS mRNA, NO amounts increased significantly from 12 to 24 hr. Moreover, this study demonstrated that ESP with the same hemagglutination titer as PR8 virus could induce iNOS mRNA and NO production, although the inductive activity of ESP was weaker than that of PR8 virus. Considering the dual role (beneficial and detrimental roles) of NO on certain inflammatory disorders and virus infections, the inductive activity of influenza virus on the iNOS-mediated NO production independent of its infectivity might contribute to a modification of influenza virus infection.     

Emergence of adaptability to time delay in bipedal locomotion

Based on neurophysiological evidence, theoretical studies have shown that locomotion is generated by mutual entrainment between the oscillatory activities of central pattern generators (CPGs) and body motion. However, it has also been shown that the time delay in the sensorimotor loop can destabilize mutual entrainment and result in the failure to walk. In this study, a new mechanism called flexible-phase locking is proposed to overcome the time delay. It is realized by employing the Bonhoeffer–Van der Pol formalism – well known as a physiologically faithful neuronal model – for neurons in the CPG. The formalism states that neurons modulate their phase according to the delay so that mutual entrainment is stabilized. Flexible-phase locking derives from the phase dynamics related to an asymptotically stable limit cycle of the neuron. The effectiveness of the mechanism is verified by computer simulations of a bipedal locomotion model.     

Visualization of plastid nucleoids in situ using the PEND-GFP fusion protein

Plastid DNA is a circular molecule of 120-150 kbp, which is organized into a protein-DNA complex called a nucleoid. Although various plastids other than chloroplasts exist, such as etioplasts, amyloplasts and chromoplasts, it is not easy to observe plastid nucleoids within the cells of many non-green tissues. The PEND (plastid envelope DNA-binding) protein is a DNA-binding protein in the inner envelope membrane of developing chloroplasts, and a DNA-binding domain called cbZIP is present at its N-terminus. We made various PEND-green fluorescent protein (GFP) fusion proteins using the cbZIP domains from various plants, and found that they were localized in the chloroplast nucleoids in transient expression in leaf protoplasts. In stable transformants of Arabidopsis thaliana, PEND-GFP fusion proteins were also localized in the nucleoids of various plastids. We have succeeded in visualizing plastid nucleoids in various intact tissues using this stable transformant. This technique is useful in root, flower and pollen, in which it had been difficult to observe plastid nucleoids. The relative arrangement of nucleoids within a chloroplast was kept unchanged when the chloroplast moved within a cell. During the division of plastid, nucleoids formed a network structure, which made possible equal partition of nucleoids.