Stabilities of Clostridium botulinum type B and C toxins in ruminal contents of cattle.

Purified L (large) toxins of Clostridium botulinum type B and C are more stable than M (medium) toxins in ruminal contents of cattle. That finding suggests that the stabilities of L toxins are in part responsible for the incidence of intoxication of cattle.     

A role of activated Sonic hedgehog signaling for the cellular proliferation of oral squamous cell carcinoma cell line

Sonic hedgehog (Shh) is a secreted morphogen crucial for appropriate cellular proliferation during mammalian development. The activated Shh signaling is known to predispose to human tumors such as medulloblastoma and basal cell carcinoma, while a role of Shh signaling in the other common tumors is still controversial. Here we showed the overexpression of Shh in five cell lines among 14 human oral squamous cell carcinoma (OSCC) cell lines. One of the Shh-expressing OSCC cell lines HSQ-89 showed the inhibition of G1/S transition and apoptotic cell death by treatment with Cyclopamine, a steroidal alkaloid that blocks the intracellular Shh signaling. Furthermore, we found that treatment with Y-27632, a specific inhibitor of Rho-associated kinase, mimicked the effect of Cyclopamine on the cell cycle progression of HSQ-89. Our study revealed the involvement of activated Shh signaling in the cellular proliferation of OSCC cells, indicating Shh signaling might be a good therapeutic target for OSCC.     

Kinetics and collagenolytic role of eosinophils in chronic gastric ulcer in the rat

 An association between eosinophils and tissue damage has been observed in numerous disorders. However, few reports have addressed the role of infiltrating eosinophils in gastric ulcer healing. The aim of this study was to investigate the kinetics and role of eosinophils infiltrating experimental chronic gastric ulcers in the rat. We developed a monoclonal antibody against human matrix metalloproteinase 1 (MMP1) purified from conditioned culture medium of human skin fibroblasts. Acetic acid-induced gastric ulcers were resected from rats on days 1, 3, 5, 10, 20, 40, and 180 after the days of induction (day 0). Tissue specimens were immunostained with this antibody and examined with an electron microscope. Few eosinophils were observed in the granulation tissue until day 20. By days 40 and 180, MMP1-positive eosinophils had increased in the granulation tissue of open ulcers. Azan staining revealed dispersed collagen fibers around infiltrating eosinophils. In contrast, scars demonstrated few eosinophils in fibrous tissue on days 40 and 180. Eosinophils which express MMP1 infiltrate granulation tissue at the chronic stage of gastric ulceration. The results suggest that eosinophils may play a role in tissue remodeling and deterioration of ulceration. Accepted: 18 March 1997     

ESA Hyporesponsiveness Is Associated with Adverse Events in Maintenance Hemodialysis (MHD) Patients,But Not with Iron Storage

Objective

It has been reported that hyporesponsiveness to erythropoiesis-stimulating agent (ESA) is associated with adverse events in patients on maintenance hemodialysis (MHD). However, it has not been determined whether higher iron storage is associated with an improved response, including better survival, to ESA.

Design and Method

We measured serum ferritin, hemoglobin (Hb), and transferrin saturation (TSAT) levels every three months for two years in 1,095 MHD patients. The weekly dose of ESA to Hb ratio was also calculated as an index of ESA responsiveness (ERI).

Results

A significant correlation (p<0.001, R = 0.89) between ferritin and Hb was only observed in the patients with ferritin levels <50 ng/mL. High-dose (≥50 mg/week) intravenous iron administration, female sex, low serum albumin, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use were significant predictors of a high ERI value (>280); however, serum ferritin and TSAT levels did not predict a higher ERI. In the time-dependent Cox hazard model, the risk for a composite event in the patients with a high ERI (≥280) and a high ferritin level (≥100 ng/mL) was significantly greater (hazard ratio [HR], 2.09, P = 0.033) than that for patients with a high ERI and a low ferritin (<100 ng/mL) level.

Conclusion

Hb was dependent upon ferritin levels in patients with ferritin levels <50 ng/mL but not in patients with ferritin levels ≥50 ng/mL. Patients with hyporesponsiveness to ESA had a greater risk of composite events, but ERI was unrelated to iron storage.     

Kibizu concentrated liquid suppresses the accumulation of lipid droplets in 3T3-L1 cells

Adipocyte size is closely related to the occurrence of diabetes, metabolic syndrome, and insulin resistance. Thus, researchers are searching for active substances that function to reduce adipocyte size. In the present study, we focused on sugar cane vinegar, Kibizu, and evaluated the function of Kibizu to reduce adipocyte size by using an in vitro model system, because people in Amami Oshima famous for longevity regularly consume Kibizu. Results showed that Kibizu treatment significantly reduced the size and number of lipid droplets in 3T3-L1 cells, relative to treatment with Kurozu, another traditional vinegar. Results of an extraction experiment suggest that the active components in Kibizu are lipophilic and hydrophobic. In addition, an in vivo experiment on rats treated with Kibizu showed that the active components were contained in large vein blood. Results of an additional in vivo experiment suggest that metabolites generated by Kibizu-treated rats are primarily contained or modified specifically in the large vein blood.     

Multiplex PCRs for assignment of Staphylocoagulase types and subtypes of type VI Staphylocoagulase

Staphylocoagulases (SCs) have been classified by the differences in antigenicity using a serological method. We have developed a system to classify them based on the nucleotide differences in SC genes (coa). The system was composed of three multiplex PCRs (M-PCRs): M-PCR:A, identifying types III, IV, VII, and VIII; M-PCR:B, identifying types I, II, V, and VI; M-PCR:C, identifying three subtypes of type VI. In this study, we found that coa genes of the serotype VI were not identical, but classified into three subtypes based on the nucleotide differences, especially in D2 and the central region: VIa, the coa gene carried by stp12 from human; and VIb and VIc, the coa genes carried by strains IFH556 and IFH514 isolated from bovine raw milk. The primer pair used in M-PCR:B was designed to identify all three subtypes of type VI coa. The results showed that coa types of 154 out of 155 Staphylococcus aureus strains from various origins assigned by M-PCR:A and B were identical to those obtained by serological methods, leaving a serotype IV strain unclassifiable. All 73 type VI strains were classified into one of three subtypes by M-PCR:C. Furthermore, we found that type VIa and VIb strains carried characteristic pyrogenic toxin superantigen genes, while no toxin genes were identified in type VIc strains, suggesting the correlation between the subtype of type VI coa gene and the carriage of genomic islands. Our results showed that these M-PCRs are convenient methods for SC typing that might be useful for epidemiological studies.     

Flower orientation enhances pollen transfer in bilaterally symmetrical flowers

Zygomorphic flowers are usually more complex than actinomorphic flowers and are more likely to be visited by specialized pollinators. Complex zygomorphic flowers tend to be oriented horizontally. It is hypothesized that a horizontal flower orientation ensures effective pollen transfer by facilitating pollinator recognition (the recognition-facilitation hypothesis) and/or pollinator landing (the landing-control hypothesis). To examine these two hypotheses, we altered the angle of Commelina communis flowers and examined the efficiency of pollen transfer, as well as the behavior of their visitors. We exposed unmanipulated (horizontal-), upward-, and downward-facing flowers to syrphid flies (mostly Episyrphus balteatus), which are natural visitors to C. communis. The frequency of pollinator approaches and landings, as well as the amount of pollen deposited by E. balteatus, decreased for the downward-facing flowers, supporting both hypotheses. The upward-facing flowers received the same numbers of approaches and landings as the unmanipulated flowers, but experienced more illegitimate landings. In addition, the visitors failed to touch the stigmas or anthers on the upward-facing flowers, leading to reduced pollen export and receipt, and supporting the landing-control hypothesis. Collectively, our data suggested that the horizontal orientation of zygomorphic flowers enhances pollen transfer by both facilitating pollinator recognition and controlling pollinator landing position. These findings suggest that zygomorphic flowers which deviate from a horizontal orientation may have lower fitness because of decreased pollen transfer.     

Allochthonous prey subsidies provide an asymmetric growth benefit to invasive bluegills over native cyprinids under the competitive conditions in a pond

Asymmetry in the competition abilities between invasive and native consumers can potentially influence the colonization success by invasive species. We tested whether a subsidy of allochthonous prey enhanced an asymmetric competition between invasive bluegill (Lepomis macrochirus) and two native cyprinid fish, that is, stone moroko (Pseudorasbora parva) and tamoroko (Gnathopogon elongatus elongatus). A field experiment was conducted using enclosures wherein the strength of interspecific competition and the presence/absence of allochthonous prey were manipulated. The experiment revealed that allochthonous prey alleviated the limitation of fish growths caused by a severe competition for aquatic prey resources. However, the importance of allochthonous prey differed considerably between invasive bluegill and the two native cyprinids. Individual bluegills grew faster when the allochthonous prey was supplied, whereas no difference in growth was observed in the two cyprinids whether or not allochthonous prey was supplied. Interestingly, the importance of allochthonous prey on the total amount of bluegill growth varied depending on the numerical abundance of native cyprinid competitors, and this importance increased when the native cyprinids were abundant. These findings indicated that allochthonous prey provides an asymmetric growth benefit to invasive bluegills over the two native cyprinids by alleviating asymmetrically the competition strength in a Japanese pond, especially under the conditions of severe interspecific resource competition and a limitation in the utilization of in situ prey resources.