Enhancement of Drug Resistance by Lysophosphatidic Acid Receptor-3 in Mouse Mammary Tumor FM3A Cells

Lysophosphatidic acid (LPA) acts as a simple phospholipid that interacts with G protein-coupled transmembrane LPA receptors. Recently, it has been reported that each LPA receptor plays different biological roles in acquisition of the malignant property of tumor cells. In this study, to assess the involvement of LPA receptor-3 (LPA₃) in cell survival after treatment with anticancer drugs, we generated Lpar3-expressing FM3A-a3A9 cells from mouse mammary tumor FM3A cells and examined the cell survival rate after treatment with anticancer drugs compared with Lpar3-unexpressing cells. Cells were treated with 0.005 to 10 μM of cisplatin (CDDP) or doxorubicin (DOX) for 3 days. For the CDDP and DOX treatments, the cell survival rate of FM3A-a3A9 cells was significantly higher than that of Lpar3-unexpressing cells. The expression level of the Mdr1a gene in FM3A-a3A9 cells was higher than that of Lpar3-unexpressing cells, whereas no significant difference in multidrug resistance 1b (Mdr1b) and glutathione S-transferase mu1 (Gstm1) expressions was found. These results suggest that LPA₃ may enhance the cell survival rate after treatment with anticancer drugs in mouse mammary tumor cells, correlating with increased expression of the Mdr1 gene.     

Recovery of leptospires from miniature pigs experimentally infected with Leptospira interrogans serovar Manilae strain UP-MMC under immunosuppressive conditions by dexamethasone

Leptospira interrogans serovar Manilae strain UP-MMC was inoculated into miniature pigs to assess its pathogenicity. Leptospires were recovered from the whole blood, kidneys, and livers in the acute phase without showing any clinical signs. Under immunosuppressive conditions by dexamethasone, leptospires were recovered from the kidneys and their genes were detected from the urine in the chronic phase. These results indicate that leptospires persisted in the kidneys until the chronic phase, and excretion of leptospires in the urine was enhanced under immunosuppressive conditions, resulting in horizontal transmission among pigs on farms.     

Nonsteroidal anti-inflammatory drugs induce hypermotilinemia and disturbance of interdigestive migrating contractions in instrumented dogs

Nonsteroidal anti-inflammatory drugs (NSAIDs) induce gastric ulcers due to inhibition of prostaglandin production. Prostaglandins have an influence on physiological gastrointestinal motility, but the relationships between NSAID-induced gastric ulcer, gastrointestinal motility and motilin are unknown. Fifteen dogs were allocated randomly to three groups in which either gelatin, meloxicam or indomethacin was administered. Fecal occult blood and gastrointestinal motility were monitored continuously for 6 days. In addition, analyses of the plasma motilin concentration, gastrointestinal endoscopy and gastric emptying, and detection of motilin cells were performed. Gastrointestinal motility was disturbed in the indomethacin group, presenting as disappearance of interdigestive migrating contractions (IMCs) 3 days before gastric ulcers were detected. Delayed gastric emptying and hypermotilinemia were observed significantly more often in the indomethacin group compared with the other groups. Motilin cell-crypt/villi ratio in the indomethacin group significantly decreased in the duodenum and jejunum, compared with the other groups. No significant changes in any tests were observed in the meloxicam group, when compared with the gelatin group. These findings suggest that the disturbance of IMCs caused by hypermotilinemia, with changes in motilin cell distribution, and delayed gastric emptying induced by indomethacin may contribute to the development of gastric ulcers.     

Immuno-magnetic separation and agar layer methods for the isolation of freeze-injured Yersinia enterocolitica O:8 from water

To develop an effective method to isolate an injured pathogenic Yersinia enterocolitica O:8 organism from environmental samples, we compared the isolation of freeze-injured and non-injured Y. enterocolitica O:8 and found that the isolation was more successful when immuno-magnetic separation (IMS) with anti-Y. enterocolitica O:8 antibody was used. Plating onto cefsulodin-irgasan-novobiocin (CIN) agar and Virulent Yersinia enterocolitica (VYE) agar by means of the agar layer method was found to be effective in isolating the injured cells. The alkali treatment which is generally used for selective detection of Yersinia organism failed to isolate freeze-injured pathogenic Y. enterocolitica O:8 cells. Recovery methods without using the alkali treatment were superior for detecting freeze-injured Y. enterocolitica O:8. Our results demonstrate that the IMS and the agar layer methods should be used to isolate injured pathogenic Yersinia organisms from environmental samples such as water.     

<Emphasis Type="Italic">Pythium</Emphasis> and <Emphasis Type="Italic">Phytophthora</Emphasis> species associated with root and stem rots of kalanchoe

Pythium and Phytophthora species were isolated from kalanchoe plants with root and stem rots. Phytophthora isolates were identified as Phytophthora nicotianae on the basis of morphological characteristics and restriction fragment length polymorphism (RFLP) analysis of the rDNA-internal transcribed spacer regions. Similarly, the Pythium isolates were identified as Pythium myriotylum and Pythium helicoides. In pathogenicity tests, isolates of the three species caused root and stem rots. Disease severity caused by the Pythium spp. and Ph. nicotianae was the greatest at 35°–40°C and 30°–40°C, respectively. Ph. nicotianae induced stem rot at two different relative humidities (60% and >95%) at 30°C. P. myriotylum and P. helicoides caused root and stem rots at high humidity (>95%), but only root rot at low humidity (60%).     

Searching by Differential Display for New Genes Implicated in Induced Disease Resistance of Cucumber Treated with Acibenzolar-S-methyl

Acibenzolar-S-methyl (ASM) is a chemical activator of systemic disease resistance in plants. In this study, we used differential display to identify ASM-inducible defense response genes involved in induced disease resistance. As a result, we cloned three ASM-inducible genes from cucumber, encoding a chitinase, a putative protein disulfide isomerase and a putative mitochondrial-protein-like protein. Expression of these genes was induced within 24 hr after treatment of cucumber leaves with ASM. These results suggest that differential display is a useful tool for understanding the mode of action of ASM and defense responses. Received 6 September 2000/ Accepted in revised form 11 April 2001     

Estimation of planting date in paddy fields by time-series MODIS data for basin-scale rice production modeling

Paddy and Water Environment - Projection of future changes in agricultural water demand and supply through numerical model simulations can be one of the reference materials used for long-term rural...     

Structural characterization of carangid fish myoglobins

The primary structures of myoglobin (Mb) from the following five carangid species were determined: yellowtail Seriola quinqueradiata, greater amberjack Seriola dumerili, yellowtail kingfish Seriola lalandi, Japanese horse mackerel Trachurus japonicus, and silver trevally Pseudocaranx dentex. The sequences were of varying composition both in the coding and in the noncoding regions, but all contained the open reading frame of 444 nucleotides encoding 147 amino acids. Amino acid sequence identities of carangid Mbs were in the range of 81-99%. The similarity of the heme pocket and associated heme-binding residues of carangid Mbs were evidence of the conservative nature of Mbs. Similar to the other teleost Mbs, carangid Mbs did not contain a D helix and had mostly conserved A and E helices as well as E-F and G-H inter-helical segments. Hydropathy profiles of carangid Mbs showed species-specific variations where silver trevally Mb exhibited generally higher hydrophobicity. Phylogenetic analysis based on the primary structures was in agreement with conventional morphological taxonomy, establishing close proximity of carangid Mbs with those of cichlid and scombroid, the other members of the Perciformes order.     

Ecological studies on subtropical evergreen broad-leaved forest in Okinawa, Japan: Litter production and nutrient input

Patterns of litterfall and nutrient input in a subtropical evergreen broad-leaved forest in northern Okinawa, Japan, were studied during May, 1996–April, 1999. The mean annual rate of litterfall in the five sampling plots ranged from 6.84 to 8.93 Mg ha⁻¹ yr⁻¹, of which 63.3–68.5% were leaves; 22.4–29.1% woody parts (including branches < 5.0 cm in diameter and bark); 2.8–5.0% sexual organs and 4.6–6.3% miscellaneous material. Significant differences were found among plots and among years. Significantly monthly differences pronounced seasonal patterns in litterfall were observed. Total litterfall and leaf litter showed negative correlations with relative basal area of the dominant species,Castanopsis sieboldii; and showed positive correlations with mean height of the stands. The dominant species,C. sieboldii produced an average of 2.36 Mg ha⁻¹ yr⁻¹ of leaf litter, which covered 30.5% of the annual litter production, and the nutrient input from those litterfall contributed 32.3, 28.3, 30.2, 22.2, 32.5, and 30.5% of total N, P, K, Ca, Mg, and Na, respectively. Nutrient use efficiency in litter production was high, especially for P and K compared with other broad-leaved forests in Japan indicating that P and K may be limiting in Okinawan evergreen broad-leaved forest.