Natural and experimental evidence of melt lubrication of faults during earthquakes

Melt produced by friction during earthquakes may act either as a coseismic fault lubricant or as a viscous brake. Here we estimate the dynamic shear resistance (tau(f)) in the presence of friction-induced melts from both exhumed faults and high-velocity (1.28 meters per second) frictional experiments. Exhumed faults within granitoids (tonalites) indicate low tau(f) at 10 kilometers in depth. Friction experiments on tonalite samples show that tau(f) depends weakly on normal stress. Extrapolation of experimental data yields tau(f) values consistent with the field estimates and well below the Byerlee strength. We conclude that friction-induced melts can lubricate faults at intermediate crustal depths.     

Localization of connexin 32 in spontaneous liver lesions of mice

We examined the localization of connexin 32 (Cx32), a component of gap junctions, in 24-month-old male B6C3F1 mice with spontaneously occurring hepatocellular altered foci or tumors. Immunohistochemically, Cx32-staining intensity in cell-to-cell membranes of altered hepatocytes was decreased in eosinophilic foci and increased in basophilic foci as compared to those in intact hepatocytes. These alterations were enhanced in adenomas and carcinomas with both eosinophilic and basophilic cytoplasm. In cell membranes facing on the sinusoidal portions, the intensities increased in all lesions. Image analyses confirmed that the spot areas of Cx32 were decreased in eosinophilic foci, but increased in basophilic foci, adenomas and carcinomas. These results demonstrate that Cx32 shows different expression in different types of hepatic lesions.     

Larvicidal and adulticidal activity of alkylphthalide derivatives from rhizome of Cnidium officinale against Drosophila melanogaster

The insecticidal activity of the chloroform extract of Cnidium officinale rhizomes and its constituents was investigated against larvae and adults of Drosophila melanogaster and compared with that of rotenone. Bioassay-guided isolation of the chloroform extract of C. officinale resulted in the isolation and characterization of four alkylphthalides, cnidilide (1), (Z)-ligustilide (2), (3S)-butylphthalide (3), and neocnidilide (4). The structures of these compounds were established by spectroscopic analysis. The isolated compounds 2, 3, and 4 exhibited LC50 values of 2.54, 4.99, and 9.90 micromol/mL of diet concentration against larvae of D. melanogaster, respectively. Against both sexes (males/females, 1:1) of adults (5-7 days old), compound 3 showed the most potent activity of the compounds isolated with the LD50 value of 5.93 microg/adult, comparable to that of rotenone (LD50 = 3.68 microg/adult). Structure-activity relationships of phthalides isolated suggest that the presence of conjugation with the carbonyl group in the lactone ring appeared to play an important role in the larvicidal activity. Acetylcholinesterase (prepared from the adult heads of D. melanogaster) inhibitory activity was also investigated in vitro to determine the insecticide mode of action for the acute adulticidal activity.     

Comparison of lysophospholipid levels in rat feces with those in a standard chow

Although lysophospholipids have attracted much attention due to their diverse physiological activities through their specific receptors, little is known about their metabolic fates in mammalian digestive systems after their ingestion as a minor food component. In this study, we analyzed five lysophospholipids in lipid extracts of a standard rat chow and feces of rats fed the chow by two-dimensional thin layer chromatography and liquid chromatography-tandem mass spectrometry. The most abundant lysophospholipid in the rat chow was lysophosphatidylcholine followed by lysophosphatidylethanolamine, lysophosphatidic acid (LPA), lysophosphatidylinositol and lysophosphatidylserine (LPS) in an increasing order, but their concentrations were very low in rat feces. Among the molecular species of LPS in the chow, only saturated species were detected in the feces in significant amounts. In addition, several molecular species of LPA remained in the feces in variable portions (saturated > monounsaturated > polyunsaturated). These results suggest that a portion of ingested LPA and LPS reach the rat large intestine, affecting physiological colon functions.     

Detection of the new Ehrlichia species closely related to Ehrlichia ewingii from Haemaphysalis longicornis in Yonaguni Island, Okinawa, Japan

We collected a total of 206 Haemaphysalis longicornis ticks by flagging in pastures in Yonaguni Island, Okinawa, Japan, in April 2008. Four of the 206 tick DNA samples tested were positive in a polymerase chain reaction (PCR) screening for the 16SrRNA gene of Anaplasmataceae. Partial sequences of 4 PCR products were identical to each other. Longer sequences of the 16SrRNA gene were successfully determined in 2 of the 4 tick samples, and the obtained 1,392 bp and 1,300 bp sequences revealed high similarity to the 16SrRNA gene sequences of the validated Ehrlichia species, including Ehrlichia ewingii, E. chaffeensis, and E. canis (98.3-98.6%). We also sequenced 1,304 bp of the groEL gene from the 2 tick samples, and found that these had the highest similarity to sequences of E. ewingii (94.0-94.4%) in the validated ehrlichial species. Based on the 16SrRNA and groEL gene sequences, the ehrlichial agents detected in this study were similar to the Ehrlichia species detected in Asia and may compose a new Ehrlichia species with other Ehrlichia species detected in Asia.     

Effect of α-cyclodextrin-allyl isothiocyanate on ruminal microbial methane production in vitro

The objective of the present study was to investigate the effects of α‐cyclodextrin‐allyl isothiocyanate (CD‐AI) on ruminal microbial methane production and rumen fermentation of corn starch, soluble potato starch or hay plus concentrate (1.5:1) by mixed rumen microorganisms. Diluted rumen fluid (30 mL) was incubated anaerobically at 38°C for 6 and 24 h with or without CD‐AI (0, 0.4, 0.8, 1.6 and 3.2 g/L). The pH of the medium was unchanged by CD‐AI in all substrates. The molar proportion of acetate was decreased and propionate was increased with a corresponding decrease in acetate : propionate ratio (P < 0.05). Total volatile fatty acids and butyrate were increased (P < 0.05). Ammonia‐N was decreased (P < 0.05). Except with soluble potato starch, numbers of protozoa were unchanged after 6 h. As concentration of CD‐AI increased from 0 to 3.2 g/L, fermentation of corn starch, soluble potato starch and hay plus concentrate resulted in decreased (P < 0.05) methane production of 49–100% (6 h) and 14–100% (24 h); 39–100% (6 h) and 16–100% (24 h); and 45–100% (6 h) and 17–100% (24 h), respectively. When hay plus concentrate was used as substrate, methanogenic bacteria were decreased (P < 0.05) with 0.8 g/L of CD‐AI after 6 h. Excluding the lower dose level (0.4 g/L) of CD‐AI, digestibility of neutral detergent fiber of hay plus concentrate was decreased (P < 0.05) after 24 h. A suitable level of CD‐AI could therefore be used as a supplement to inhibit methane production and improve rumen fermentation without detrimental effects on fiber digestion.     

Role of the rice blast resistance gene Pi-cd in rice (Oryza sativa) breeding programmes

A series of DNA markers for various agronomic traits may accelerate the success of marker-assisted selection in practical plant breeding programmes. Here, we developed DNA markers for the blast resistance gene Pi-cd. In this study, we examined the effects of the Pi-cd locus on not only blast resistance but also agronomic traits in agriculture. We developed three pyramiding lines (PLs) coupling Pi-cd with three blast resistance genes, pi21, Pi35 and Pi39. The effect of Pi-cd on blast resistance was dependent on the coupled resistance genes. Then, we evaluated the effects of Pi-cd on 13 agronomic traits. Amylose content and 1,000-grain weight showed significant differences between the PLs and current commercial varieties, which had no negative effects on agronomic trait values. Furthermore, we investigated the distribution of genotype for the Pi-cd locus among varieties of upland rice. The KT genotype specific to rice blast resistance may be predominant in the varieties. The results suggested that Pi-cd has the potential to be useful for improving blast resistance in rice breeding programmes.     

Can research on the early marine life stage of juvenile chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis> forecast returns of adult salmon? A case study from eastern Hokkaido,Japan

To examine the efficacy of juvenile salmon research as a tool for forecasting adult returns, the results from a study on the early marine life stage of juvenile chum salmon, conducted in the Nemuro Strait during 1999–2002 (i.e., 1998–2001 brood years), were compared with the return rates of adult salmon. Among the four brood years, the 2000 brood year (i.e., salmon migrating to the sea in 2001) was previously reported as showing higher abundance, higher growth rate and better somatic condition during the coastal residency period. Consequently, we expected it to have the highest return rate, under a hypothesis that juvenile survival in coastal residency regulates brood-year strength. Contrary to this expectation, the 2000 brood year had almost the lowest return rate. Alternatively, a statistical model in which sea surface temperature during the first year of marine life and size at release were utilized as explanatory variables reconstructed the actual variability in return rates more accurately than that based on the early marine life stage. Possible reasons for the discrepancy between the results of the juvenile salmon research and adult returns are discussed, and we suggest improvements for future research on juvenile salmon.     

Prebiotic effect of glycerol galactoside isolated from color-faded nori in rats

Glycerol galactoside (GG; floridoside: 2-O-glycerol-α-d-galactopyranoside, and isofloridoside: 1-O-glycerol-α-d-galactopyranoside) is known to be a component of edible red seaweed nori. Recently, we have found that low-quality nori (color-faded nori), which has a low protein content, contains a large quantity of GG. From further studies, we have also found that GG has prebiotic characteristics in vitro. In this study, we evaluated the in vivo prebiotic activity of GG in rats. Dietary GG selectively increased the cecal Bifidobacterium count in rats. Other indices of prebiotics, such as pH of cecal content, organic acid concentrations, and fecal weight, also supported the existence of prebiotic activity of GG. The present data will also contribute to the development of a new method of utilizing color-faded nori as a health-promoting foodstuff.