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排序方式: 共有351条查询结果,搜索用时 15 毫秒
1.
Ishida Takuya Uehara Yoshitoshi Ikeya Tohru Haraguchi Takashi F. Asano Satoshi Ogino Yohei Okuda Noboru 《Limnology》2020,21(3):403-413
Limnology - Controlling phosphorous (P) loads from rice fields is important for the conservation of aquatic ecosystems, in part because P is relatively concentrated at its sources. Recently, winter... 相似文献
2.
Bacteriophages (or phages) play major roles in the evolution of bacterial pathogens via horizontal gene transfer. Multiple phages are often integrated in a host chromosome as prophages, not only carrying various novel virulence-related genetic determinants into host bacteria but also providing various possibilities for prophage-prophage interactions in bacterial cells. In particular, Escherichia coli strains such as Shiga toxin (Stx)-producing E. coli (STEC) and enteropathogenic E. coli (EPEC) strains have acquired more than 10 prophages (up to 21 prophages), many of which encode type III secretion system (T3SS) effector gene clusters. In these strains, some prophages are present at a single locus in tandem, which is usually interpreted as the integration of phages that use the same attachment (att) sequence. Here, we present phages integrating into T3SS effector gene cluster-associated loci in prophages, which are widely distributed in STEC and EPEC. Some of the phages integrated into prophages are Stx-encoding phages (Stx phages) and have induced the duplication of Stx phages in a single cell. The identified attB sequences in prophage genomes are apparently derived from host chromosomes. In addition, two or three different attB sequences are present in some prophages, which results in the generation of prophage clusters in various complex configurations. These phages integrating into prophages represent a medically and biologically important type of inter-phage interaction that promotes the accumulation of T3SS effector genes in STEC and EPEC, the duplication of Stx phages in STEC, and the conversion of EPEC to STEC and that may be distributed in other types of E. coli strains as well as other prophage-rich bacterial species. 相似文献
3.
4.
The sensitivity of the agar plate method for the diagnosis of Strongyloides stercoralis was studied experimentally. Results demonstrated that this method was sensitive enough to detect S. stercoralis even when only a few worms were present. 相似文献
5.
Norio Ohashi Yoko Koyama Hiroshi Urakami Masahiro Fukuhara Akira Tamura Fumihiko Kawamori Seigo Yamamoto Shiro Kasuya Kentaro Yoshimura 《Microbiology and immunology》1996,40(9):627-638
A total of 40 strains of Orientia tsutsugamushi (34 isolates from patients and trombiculid mites in Japan, and 6 prototype strains of antigenic variants) were examined for classification based on the reactivities with type-specific monoclonal antibodies in indirect immunofluorescence tests, and on the restriction fragment length polymorphism of a polymerase chain reaction (PCR)-amplified 56-kilodalton type-specific antigenic protein gene. By these methods, several antigenic and genotypic variants were found among the strains, and these variants were classified into types and further into subtypes. These results suggest that there are many variants in O. tsutsugamushi, and the methods used here seem to be useful for the systematic classification of the numerous variants. A strain which may be a new type distinguishable from those identified previously was also found in this study. Furthermore, variety in the degree of pathogenicity in mice related to type and/or subtype classification were observed. 相似文献
6.
N. Ohmiya Shinsuke Saga Masaharu Ohbayashi Ken-ichi Kozaki Osamu Miyaishi Miya Kobayashi Shiro Kasuya Tomiyasu Arisawa Hidemi Goto Tetsuo Hayakawa 《Histochemistry and cell biology》1997,108(1):27-34
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 相似文献
7.
K Shigenobu K Sawada Y Kasuya 《Canadian journal of physiology and pharmacology》1980,58(11):1300-1306
Histamine stimulates the heart by interacting with cardiac histamine receptors. We investigated the postnatal changes in histamine sensitivity with spontaneously beating right atria and electrically driven left atria and right ventricular papillary muscles from 0-, 5-, and 10-day-old and adult guinea pigs. The positive chronotropic response to histamine in right atria was antagonized by cimetidine but not by chlorpheniramine at any age. Chlorpheniramine did not antagonize the positive inotropic effect of histamine and 2-(2-pyridyl)ethylamine in the immature left atria but it blocked the positive inotropic effect in the adult; cimetidine had no effect. The positive inotropic effect of histamine in right ventricular muscles was not affected by chlorpheniramine in immature right ventricular muscles but was antagonized in the adult. These results suggest that, in immature left atria and right ventricular muscles, there is no H1-receptor system mediating the positive inotropic effect of histamine and that, as age advances, this system begins to mediate the positive inotropic effect. In immature left atria, non-H1 and non-H2 receptors exist and mediate the positive inotropic effect of histamine. 相似文献
8.
The polymerized albumin hypothesis was proposed for the mechanism of a hepatitis B virus (HBV) infection of human liver parenchymal cells on the basis that a receptor for polymerized albumin treated with glutaraldehyde was detected on isolated human liver parenchymal cells. However, some controversy exists regarding this hypothesis, because a receptor for formaldehyde-treated bovine serum albumin (f-BSA) has been found on liver non-parenchymal cells. Therefore, we characterized the uptake of polymerized rat serum albumin (p-RSA) and f-BSA by rat liver in vivo, and their bindings to liver cells in vitro. Most p-RSA and f-BSA was taken up by the liver after intravenous administration, and the uptake of p-RSA was inhibited by a 1,000-fold excess of f-BSA. In addition, more than 80% of p-RSA taken up by the liver was found in the non-parenchymal cells, and the remainder was found in the parenchymal cells. P-RSA as well as f-BSA could bind to isolated rat liver parenchymal and non-parenchymal cells. Furthermore, p-RSA and f-BSA could bind to isolated rat liver cell plasma membranes, and these bindings were completely inhibited by 1,000-fold excess of either f-BSA or p-RSA. These results indicate that there is a receptor, which can recognize both p-RSA and f-BSA, on not only rat liver non-parenchymal cells but also the parenchymal cells. It is also indicated that the receptor on the parenchymal cells as well as the non-parenchymal cells is involved in the in vivo uptake of p-RSA.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
To investigate the influence of diabetes mellitus on the responsiveness of the vascular smooth muscle, the effects of various vasoactive agents on the reactivity of the vascular smooth muscle from diabetic animals have been undertaken, focusing on the functional changes in the endothelium, alpha-adrenoceptors, beta-adrenoceptors, voltage-dependent Ca(2+)-channels, receptor-operated Ca(2+)-channels, phosphatidylinositol turnover and potassium channels. Among the functional changes, it is a common phenomenon that decreases in acetylcholine-induced production of cyclic GMP are due to the attenuation of release of endothelium-derived relaxing factor through an impairment of endothelium; this observation was found in both rats and rabbits with diabetes mellitus. These functional changes in diabetes may be responsible for the vascular complications such as coronary heart disease, cerebrovascular disease, and an acceleration in atherosclerosis. 相似文献
10.
Data from the North Pacific sperm whale (Physeter catodon Linnaeus, 1758) fishery were examined for a possible density dependent change in growth during 40 yr harvesting after World War II. Early in this period males from the eastern stock were 16.8 m or less in length. By the early 1970s the largest males in the catch exceeded 16.8 m in length and reached 18.9 m in the late 1970s. The proportion of males measuring over 16.8 m, among sexually mature males (≥14.0 m), increased from 0 to >20% during the 1970s. Increases in the maximum size of males were possibly preceded by a change in the frequency distribution of body lengths in the middle 1960s when only 10% of the postwar catch had been taken. Testis weights suggested an increase in body length at sexual maturity. Two of the three putative North Pacific stocks showed similar growth changes. Adult males taken in the Bering Sea did not show such changes during the exploitation which ended in 1972 because of overfishing. Females showed no detectable change in body size. It is concluded that: (1) density dependent effects on male growth are greater before sexual maturity than after it, (2) males may show density dependent changes even at a population level above 90% of the carrying capacity, (3) polygynous males acquire more mates and realize higher reproductive success because of increased body size, and (4) females appear to maximize production by maturing earlier and shortening calving intervals in response to density change. 相似文献