Ultrasonic vocalization responses in genetically high- and low-emotional rats.

Tsukuba High Emotional (THE) and Tsukuba Low Emotional (TLE) strains of rats have been congenitally bred for use in studies of emotionality. The current study investigated THE and TLE strain differences in the footshock-induced ultrasonic vocalization responses of adult male rats. Ultrasonic vocalization response inducibility (ratio of rats emitting ultrasounds) and vocalization activity in THE rats were statistically higher than in TLE rats. We next examined the causal relation between the ultrasonic vocalizations and the activation of the pituitary-adrenocortical axis in response to footshocks in these two strains of rats. Rats were sorted into two groups, vocalizing and non-vocalizing, after being exposed to the shock regimen daily for 5 successive days. Basal plasma concentrations of ACTH and corticosterone were not different between THE and TLE rats. After receiving footshocks, significant increases in plasma concentrations of ACTH and corticosterone were induced in both strains of rats. These increases in plasma concentrations of ACTH and corticosterone were significantly higher in THE than in TLE rats. However, in vocalizing and non-vocalizing rats of both strains, no statistical differences in plasma concentrations of ACTH and corticosterone were observed after footshocks. These findings suggest that the high emotionality of the adult male rats was reflected in the emission of ultrasounds, and that the emission of ultrasonic vocalizations might not be related to the activation of the pituitary-adrenocortical axis.     

Cloning of a Novel Rat Gene, DB83, That Encodes a Putative Membrane Protein

Using a partial cDNA sequence and a 5'-RACE technique, we isolateda novel cDNA from rat liver referred to as DB83. DB83 had fourhydrophobic trans-membrane domains and one N-myristoylationsite as well as multiple possible phosphorylation sites. Thedb83 gene was highly expressed in the liver and significantlyin brain, lungs and kidneys. We suggest that DB83 is a tissue-specificputative membrane protein.     

Formation of Keto and Hydroxy Compounds of Linoleic Acid in Submitochondrial Particles of Bovine Heart

To observe lipid peroxidation of additive-free submitochondrial particles, we incubated submitochondrial particles in the absence of exogenous irons and t-butyl hydroperoxide. After the incubation, the phospholipids were hydrolyzed by phopholipase A₂, and the fatty acid constituents were analyzed by high-performance liquid chromatography, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry. Contrary to a commonly accepted theory, lipid peroxidation in the submitochondrial particles did not need the addition of NADH. In the phospholipid constituent fatty acids of the oxidized submitochondrial particles, derivatives of hydroperoxides of linoleic acid such as keto, hydroxy, trihydroxy, and hydroxyepoxy compounds were generated. Lipid peroxidation in the submitochondrial particles was not inhibited by the addition of catalase, superoxide dismutase, hydroxyl radical scavengers, or ethylenediaminetetraacetic acid, but was inhibited by the addition of KCN, antimycin-A, NADH, ubiquinol, deferoxamine mesylate, ascorbic acid, and -tocopherol. The cardiolipin–cytochrome c lipid peroxidation system could mimic the lipid peroxidation of the submitochondrial particles, in terms of linoleic acid products and the inhibitory patterns of radical scavengers and electron transfer chain inhibitors. Thus, lipid peroxidation in the submitochondrial particles seems to be due to phospholipid–hemoprotein lipid peroxidation systems such as the cardiolipin–cytochrome c system.     

Effect of DNA preparation from laver (Porphyra yezoensis) thalli on reproducibility of RAPD (random amplified polymorphic DNA) patterns

Laver (Porphyra yezoensis) DNAs were extracted from thalli with five different procedures and used for RAPD (random amplified polymorphic DNA) analysis as templates. Restriction enzyme-digestive DNAs were obtained with all procedures examined. However, RAPD patterns generated with these DNAs appeared highly irreproducible and were considerably different from each other. When DNAs purified with CsCl gradient centrifugation were used for RAPD analysis as templates, highly reproducible RAPD patterns were obtained, suggesting that unpurified DNAs extracted from thalli with all five extraction procedures contained an excess of RNA, polysaccharides and/or other materials which affected the RAPD reproducibility. Thus, results indicated that purification of DNA is essential to produce reproducible RAPD patterns of Porphyra DNA. This revised version was published online in June 2006 with corrections to the Cover Date.     

Responses of Ribulose-1,5-Bisphosphate Carboxylase,Cytochrome f,and Sucrose Synthesis Enzymes in Rice Leaves to Leaf Nitrogen and Their Relationships to Photosynthesis

The photosynthetic gas-exchange rates and various biochemical components of photosynthesis, including ribulose-1,5-bisphosphate carboxylase (Rubisco) content, cytochrome (Cyt) f content, and the activities of two sucrose synthesis enzymes, were examined in young, fully expanded leaves of rice (Oryza sativa L.) grown hydroponically in different nitrogen concentrations. The light-saturated rate of photosynthesis at an intercellular CO2 pressure of 20 Pa (CO2-limited photosynthesis) was linearly dependent on leaf nitrogen content, but curvilinearly correlated with Rubisco content. This difference was due to a greater than proportional increase in Rubisco content relative to leaf nitrogen content and the presence of a CO2 transfer resistance between the intercellular air spaces and the carboxylation sites. CO2-limited photosynthesis was proportional to Cyt f content, one of the key components of electron transport, but was not proportional to the activities of cytosolic fructose-1,6-bisphosphatase and sucrose phosphate synthase, the two regulatory enzymes of sucrose synthesis. Light-saturated photosynthesis above an intercellular CO2 pressure of 60 Pa (CO2-saturated photosynthesis) was curvilinearly dependent on leaf nitrogen content. This CO2-saturated photosynthesis was proportional to Cyt f content in the low- and normal-nitrogen leaves, and correlated better with the activities of cytosolic fructose-1,6-bisphosphatase and sucrose phosphate synthase in the high-nitrogen leaves. The increase in the activities of these two enzymes with increasing leaf nitrogen was not as great as the increase in Cyt f content. Thus, as leaf nitrogen increased, the limitation caused by the activities of sucrose synthesis enzymes came into play, which resulted in the curvilinear relationship. However, this limitation by sucrose synthesis enzymes did not affect photosynthesis under normal ambient air.     

The effect on enterotoxicity of protease purified from Vibrio cholerae O1

Abstract The effect on enterotoxicity of protease purified from Vibrio cholerae O1 was investigated by the inoculation of live vibrio cells into the protease-treated loops of the ileal loop model. Fluid accumulation ratios in the protease-treated loops were elevated in a dose-dependent manner by challenge with live vibrio cells byt not that with toxin. An enhancement effect of protease on enterotoxicity was observed in both serotypes of V. cholerae O1 and V. cholerae non-O1. It is suggested, therefore, that the enterotoxicity was enhanced by treatment with protease when live vibrio cells were inoculated into the ileal loops of rabbits.     

Epidemiological and Ecological Studies of Japanese Encephalitis in Okinawa,Subtropical Area in Japan. I. Investigations on Antibody Levels to Japanese Encephalitis Virus in Swine Sera and Vector Mosquito in Okinawa,Miyako and Ishigaki Islands

From 1985 to 1989, serum specimens of swine raised in the northern, central and southern areas in Okinawa island were examined for Japanese encephalitis (JE) virus antibody by ELISA and hemagglutination-inhibition test. The antibody positive rate was found to be higher in the north and central than in the south. The 2-mercaptoethanol sensitive antibody to JE was detected mostly in June and July, and occasionally in other months except February and March. There was no month when all specimens from three areas turned antibody-negative simultaneously, indicating that JE virus transmission to swine lasted longer in Okinawa island than in other temperate areas in Japan. From 1986 to 1991, the vector mosquitoes (Culex tritaeniorhynchus) were collected in a pig farm in the south of Okinawa island. A total of 153 strains of JE virus was isolated from the vector mosquitoes mainly in June. In Miyako and Ishigaki islands, the antibody positive rate in swine sera was found to be extremely low, compared with that in Okinawa island. In Miyako island, where no paddy rice field is cultivated, a few adults as well as larvae of the vector mosquito were collected, while in Ishigaki island, where there are many watered rice fields, a lot of adults as well as larvae were collected. Although the environmental situation is quite different between the two islands, JE virus transmission appeared to be very low in both islands.     

Heparin and dibutyryl cAMP modulate gene expression in stimulated human saphenous vein smooth muscle cells

Summary Increased expression of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) A chain, and tissue plasminogen activator (tPA) by smooth muscle cells (SMC) has been postulated to mediate the progression of intimal hyperplasia. We tested whether heparin would suppress the expression of these genes in stimulated human saphenous vein SMC. Quiescent cultured human saphenous vein SMC were stimulated for 4 h with heat-inactivated fetal bovine serum (10% by vol) in the presence or absence of heparin (1 to 250μg/ml). Heparin (50μg/ml) attenuated the induction by serum of bFGF mRNA, tPA mRNA, and tPA secretion. Nonanticoagulant heparin also attenuated serum induction of bFGF and tPA mRNA levels. To further study the role of second messenger signaling, a more specific mode of SMC stimulation was used with thrombin (3 U/ml) in the presence or absence of dibutyryl cyclic AMP (Bu₂-cAMP; 0.5 mM). In contrast to heparin, which had no effect on PDGF expression, Bu₂-cAMP decreased the induction by thrombin of PDGF-A chain mRNA levels. In thrombin-stimulated SMC, Bu₂-cAMP significantly decreased secretion of PDGF-AA protein. Thrombin, however, caused an increase in bFGF mRNA levels which was potentiated by Bu₂-cAMP with associated potentiation by Bu₂-cAMP of intracellular bFGF protein levels. The induction of tPA mRNA and tPA secretion by thrombin was sharply blocked by Bu₂-cAMP. These results suggest that heparin reduces intimal hyperplasia at least partly via partial inhibition of SMC gene expression.     

Vegetation pattern and microtopography on a landslide scar of Mt Kiyosumi,central Japan

Vegetation pattern and microtopography were examined on a mountain slope with a rotational type landslide scar on Mt Kiyosumi, central Japan. Similarities of distribution patterns among 55 woody species were calculated using Cole's species association coefficient, and based on them, seven vegetation units were classified using cluster analysis and principal coordinates analysis. The seven vegetation units coincide with seven microtopographical facets at 10¹ to 10² m² order. Furthermore, these vegetation units were grouped into three higher categories by reciprocal averaging and principal coordinates analysis. They were ridge slopes, surrounding slopes and landslide slopes. The three categories were arranged in the above-mentioned order based on similarity in floristic composition. In the ridge slopes, late-successional trees and deciduous trees had high relative basal areas. In the surrounding slopes,Euptelea polyandra and other deciduous trees had high relative basal areas. In the landslide slopes,E. polyandra and deciduous shrubs had high relative basal areas. The density and the age distributions ofE. polyandra, a typical pioneer tree which invades disturbed sites, suggested that the severity of soil surface disturbances increase in this order. The disturbance regime explains the vegetation pattern on the study site, where the rotational type landslide had occurred.