Predatory Potential of Freshwater Animals on an Invasive Agricultural Pest, the Apple Snail Pomacea canaliculata (Gastropoda: Ampullariidae), in Southern Japan

The apple snail Pomacea canaliculata is an invasive species and a serious pest of rice in many Asian countries. We studied predatory activities of various animals living in Japanese freshwater habitats, by keeping each individual of a potential predator species with 36 snails of various sizes for three days in the aquarium. Forty-six species were tested, and 26 in eight classes fed on small snails. A species of leech, crabs, the common carp, turtles, the mallard duck and the Norway rat attacked even adult snails of 20–30 mm in shell height. These findings will be helpful in identifying effective predators for biological control of the pest snail. In addition, most of the animals attacking snails are reported to be common in rivers or ponds, but few live in modernized paddy fields having little connections with natural water systems. This may be a reason why this snail maintains large populations in paddy fields but not in other freshwater habitats.     

Modulation of rat cecal microbiota by administration of raffinose and encapsulated Bifidobacterium breve

To investigate the effects of administration of raffinose and encapsulated Bifidobacterium breve JCM 1192T cells on the rat cecal microbiota, in a preclinical synbiotic study groups of male WKAH/Hkm Slc rats were fed for 3 weeks with four different test diets: basal diet (group BD), basal diet supplemented with raffinose (group RAF), basal diet supplemented with encapsulated B. breve (group CB), and basal diet supplemented with both raffinose and encapsulated B. breve (group RCB). The bacterial populations in cecal samples were determined by fluorescence in situ hybridization (FISH) and terminal restriction fragment length polymorphism (T-RFLP). B. breve cells were detected only in the RCB group and accounted for about 6.3% of the total cells as determined by FISH analysis. B. breve was also detected only in the RCB group by T-RFLP analysis. This was in contrast to the CB group, in which no B. breve signals were detected by either FISH or T-RFLP. Increases in the sizes of the populations of Bifidobacterium animalis, a Bifidobacterium indigenous to the rat, were observed in the RAF and RCB groups. Principal-component analysis of T-RFLP results revealed significant alterations in the bacterial populations of rats in the RAF and RCB groups; the population in the CB group was similar to that in the control group (group BD). To the best of our knowledge, these results provide the first clear picture of the changes in the rat cecal microbiota in response to synbiotic administration.     

Human T Cell Leukemia Virus Type 1 (HTLV-1) Antibodies in Healthy Populations and Renal Transplanted Patients in the North-East of Brazil

The seroprevalence of human T cell leukemia virus type 1 (HTLV-1) infection was investigated in Brazilians (570): native inhabitants (298) and descendants from Japanese (272) living in Recife and its neighborhoods—North-east of Brazil. Furthermore, polytransfused renal transplanted patients (54) were also examined for the serological status to this virus. The seropositivity to HTLV-1, screened by enzyme-linked immunosorbent assay (ELISA), was low: 1.34% for the local population and 0.73% for the descendants from Japanese. However, the seropositivity for the renal transplanted patients was found to be 11.1%. This higher value suggests that this retrovirus infection seems to be of importance in this clinical condition.     

Electronic structures of donor-acceptor polymers based on polythiophene,polyfuran and polypyrrole

Theoretical results on the geometric and electronic structures of some donor-acceptor polymers based on polythiophene (X=S), polyfuran (X=O) and polypyrrole (X=NH) were obtained, using a one-dimensional tight-binding self-consistent field crystal-orbital (SCF-CO) method at the MNDO-AM1 level of approximation. The repeat unit of these polymers consits of a bithiophene, furan or bipyrrole unit bridged by an electron-accepting group or. The optimized geometries of the polymers show a strong dependence on the nature of the electron donating group X. All the polymers studied are predicted to have band gap values ranging between 1 eV and 2 eV. An analysis of their -bond order data and of the patterns of their frontier orbitals shows they have benzenoid-like electronic structures.     

Protective effect of NK1.1(+) T cells as well as NK cells against intraperitoneal tumors in mice

Peritoneal resident cells of mice normally contain small populations of NK cells and NK1.1(+) alphabetaT cells. These populations increased after either 3LL or EL4 tumor inoculations into the peritoneal cavity. In vivo depletion of NK cell alone by anti-asialo GM1 (ASGM1) Ab significantly decreased survival time of tumor-injected mice, while depletion of both NK cells and NK1.1(+) T cells by anti-NK 1.1 Ab greatly shortened mouse survival time. NK1. 1(+) T cells in peritoneal cavity consist of a larger proportion of double-negative T cells and smaller populations of CD4(+) T cells and Vbeta8(+) T cells compared with liver NK1.1(+) T cells and normally lack Vbeta2(+) T cells. Tumor inoculation induced rapid IL-12 and IFN-gamma mRNA in tumor-infiltrating mononuclear cells (TIM). Although anti-NK1 Ab pretreatment in vivo abrogated IFN-gamma mRNA expression and IFN-gamma production of TIM, NK cell depletion alone by anti-ASGM1 Ab pretreatment retained IFN-gamma mRNA expression and partly inhibited IFN-gamma production of TIM. Peritoneal NK cells as well as NK1.1(+) T cells but not NK1.1(-) T cells of 3LL cell- or EL4 cell-injected mice showed cytotoxicities against the same tumor cells. Further, either anti-IL-12 Ab or anti-IFN-gamma Ab ip injection significantly shortened EL4 cell-inoculated mouse survival time. Our findings suggest that peritoneal macrophages activated by tumors produce IL-12 which activates NK cells and NK1.1(+) T cells to produce IFN-gamma and both NK cells and NK1.1(+) T cells are important in suppressing the growth of the intraperitoneal tumors.     

Induction of efficient antitumor immunity using dendritic cells activated by recombinant Sendai virus and its modulation by exogenous IFN-beta gene

Dendritic cell (DC)-based cancer immunotherapy has been paid much attention as a new and cancer cell-specific therapeutic in the last decade; however, little clinical outcome has been reported. Current limitations of DC-based cancer immunotherapy include sparse information about which DC phenotype should be administered. We here report a unique, representative, and powerful method to activate DCs, namely recombinant Sendai virus-modified DCs (SeV/DC), for cancer immunotherapy. In vitro treatment of SeV without any bioactive gene solely led DCs to a mature phenotype. Even though the expression of surface markers for DC activation ex vivo did not always reach the level attained by an optimized amount of LPS, superior antitumor effects to B16F1 melanoma, namely tumor elimination and survival, were obtained with use of SeV-GFP/DC as compared with those seen with LPS/DC in vivo, and the effect was enhanced by SeV/DC-expressing IFN-beta (SeV-murine IFN-beta (mIFN-beta)/DC). In case of the treatment of an established tumor of B16F10 (7-9 mm in diameter), a highly malignant subline of B16 melanoma, SeV-modified DCs (both SeV-GFP/DC and SeV-mIFN-beta/DC), but not immature DC and LPS/DC, dramatically improved the survival of animals. Furthermore, SeV-mIFN-beta/DC but not other DCs could lead B16F10 tumor to the dormancy, associated with strongly enhanced CD8+ CTL responses. These results indicate that rSeV is a new and powerful tool as an immune booster for DC-based cancer immunotherapy that can be significantly modified by IFN-beta, and SeV/DC, therefore, warrants further investigation as a promising alternative for cancer immunotherapy.     

Flavonoid composition of fruit tissues of citrus species

An HPLC analysis was performed on the concentrations of flavonoids in 42 species and cultivars of the Citrus genus and those of two Fortunella and one Poncirus species according to the classification system established by Tanaka. The composition of 8 flavanones and 9 flavone/ols for these species was determined in the albedo, flavedo, segment epidermis and juice vesicle tissues, and those in the fruit and peel tissues were calculated from the composition data of the tissues. A principal component analysis showed that such neohesperidosyl flavonoids as neoeriocitrin, naringin, neohesperidin, and rhoifolin had large factor loading values in the first principal component for each tissue. The flavonoid composition of citrus fruits was approximately the same within each section of Tanaka's system, except for the species in the Aurantium section and those with a peculiar flavonoid composition such as Bergamot (C. bergamia), Marsh grapefruit (C. paradisi), Sour orange (C. aurantium), and Shunkokan (C. shunkokan). The Aurantium section included both naringin-rich and hesperidin-rich species.     

Inhibition of the Prostaglandin Transporter PGT Lowers Blood Pressure in Hypertensive Rats and Mice

Inhibiting the synthesis of endogenous prostaglandins with nonsteroidal anti-inflammatory drugs exacerbates arterial hypertension. We hypothesized that the converse, i.e., raising the level of endogenous prostaglandins, might have anti-hypertensive effects. To accomplish this, we focused on inhibiting the prostaglandin transporter PGT (SLCO2A1), which is the obligatory first step in the inactivation of several common PGs. We first examined the role of PGT in controlling arterial blood pressure blood pressure using anesthetized rats. The high-affinity PGT inhibitor T26A sensitized the ability of exogenous PGE₂ to lower blood pressure, confirming both inhibition of PGT by T26A and the vasodepressor action of PGE₂ T26A administered alone to anesthetized rats dose-dependently lowered blood pressure, and did so to a greater degree in spontaneously hypertensive rats than in Wistar-Kyoto control rats. In mice, T26A added chronically to the drinking water increased the urinary excretion and plasma concentration of PGE₂ over several days, confirming that T26A is orally active in antagonizing PGT. T26A given orally to hypertensive mice normalized blood pressure. T26A increased urinary sodium excretion in mice and, when added to the medium bathing isolated mouse aortas, T26A increased the net release of PGE₂ induced by arachidonic acid, inhibited serotonin-induced vasoconstriction, and potentiated vasodilation induced by exogenous PGE₂. We conclude that pharmacologically inhibiting PGT-mediated prostaglandin metabolism lowers blood pressure, probably by prostaglandin-induced natriuresis and vasodilation. PGT is a novel therapeutic target for treating hypertension.     

Oscillatory membrane currents paradoxically induced via NO-activated pathways in detrusor cells

Oscillatory inward membrane currents (I(oscil-in)) reflecting intracellular Ca(2+) ([Ca(2+)](i)) activity in detrusor cells, are thought to play an important role in producing tonic bladder contractions during micturition. The present patch clamp study revealed a new activation mechanism: sodium nitroprusside (SNP), a nitric oxide (NO) donor induced I(oscil-in) in a subpopulation of detrusor cells. The inhibitory effect of niflumic acid on SNP-induced I(oscil-in) suggests that Ca(2+)-activated Cl(-) channels are responsible for this current. In addition, SNP-induced I(oscil-in) required the cooperation of Ca(2+) influx through SK&F96365-sensitive channels and intracellular Ca(2+) release channels sensitive to ryanodine but insensitive to xestospongin C (XeC). This is also true for muscarinic agonist (carbachol: CCh)-induced I(oscil-in). However, 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), a guanylyl cyclase inhibitor, suppressed SNP-induced I(oscil-in) but not CCh-induced I(oscil-in). The results suggest that a subpopulation of detrusor cells employ the NO/cGMP cascade to potentiate bladder contraction. Mechanisms underlying NO-induced I(oscil-in) are likely to contribute not only to the physiology but also to the pathophysiology of the lower urinary tract.