Nematocidal activities of thiabendazole and ivermectin against the larvae of Strongyloides ratti and S. venezuelensis     

Satou T  Koga M  Koike K  Tada I  Nikaido T 《Veterinary parasitology》2001,99(4):311-322

With the aim of developing therapeutic agents for strongyloidosis, the disease caused by infection with Strongyloides stercoralis, we established a novel assay technique using S. ratti and S. venezuelensis as models for S. stercoralis. The newly developed assay technique was found to more accurately represent treatment-induced larval paralysis than existing assays. Our method uses paper disks impregnated with the test solution, which even allows materials that are sparingly soluble in water to be tested. An inverted microscope was used to observe the larval states, and these states were recorded using a digital camera. We observed the activities of ivermectin and thiabendazole against larvae and calculated larval motility and velocity. These two factors were then combined to determine the overall viability of larvae at selected concentrations. The activities of the anthelmintics were compared by calculating the concentrations at which 50% viability was demonstrated, or in other words, the concentration at which paralysis was caused in 50% of the individuals (50% paralysis concentration; PC(50)). Evaluations after 24h of exposure yielded the following reproducible PC(50) values for ivermectin and thiabendazole, respectively: S. ratti, 2.4 and 140 microM; and S. venezuelensis, 2.3 and 190 microM. After treatment with ivermectin, there was a tendency for larval motility to be greater than that of the controls at low concentrations, a result that might be associated with its mechanism of action.  相似文献   

Inter-tree and intra-tree variations in ring width and wood density components in balsam fir (Abies balsamea)     

Koga  S.  Zhang  S. Y. 《Wood Science and Technology》2004,38(2):149-162

This study quantified and compared intra-tree and inter-tree variations in ring width and wood density components in balsam fir (Abies balsamea) grown in Quebec, Canada. In addition, the study examined correlations between ring width and wood density components at different stem positions from the stump level to the stem top. Ring width and wood density components of individual rings were measured by X-ray densitometry. Both the intra- and inter-tree variations in balsam fir are large, but the inter-tree variation is relatively smaller than the intra-tree variation. Much of the intra-tree variation is due to the radial variation, whereas the axial variation is much smaller. Compared to ring width and its components, wood density characteristics show a considerably smaller variation at both the inter- and intra-tree level. In almost all wood characteristics studied (except for latewood width), the intra- and inter-tree variations are more or less influenced by tree age. Cambial age explains more intra-tree variation in wood density components than ring width, whereas more intra-tree variation in ring width components is due to ring width. Cambial age and ring width explain a comparable percentage of variation in ring density. Only a few of the correlations between ring width and wood density components vary significantly with stem position from the stump to the stem top at the inter-tree level. In balsam fir, a negative correlation between ring density and ring width is significant in the butt log, but the correlation decreases to an insignificant level at and above a height of 3.0 m.  相似文献   

Temperature variations during grain filling obtained in growth tunnel experiments and its influence on protein content,polymer build-up and gluten viscoelastic properties in wheat     

Anette Moldestad  Bernt Hoel  Ulrike Böcker  Shiori Koga  Ellen Færgestad Mosleth  Anne Kjersti Uhlen 《Journal of Cereal Science》2014

The aim of this study was to investigate effects of temperature during grain filling on gluten quality characteristics at a lower to moderate temperature range. Experiments with two wheat varieties grown in field covered by polypropylene tunnels during grain filling were performed in two seasons. Mean day temperature differences achieved within the tunnel were approximately 2–2.5 °C from the open to the closed end. There were significant effects of temperature on grain maturity time, thousand grain weight and protein content. The resistance to stretching of the gluten doughs increased with the increasing day temperatures. This was reflected in the proportion of unextractable polymeric proteins (UPP). The results suggest that increases in temperature within this temperature range affect the polymerization of polymeric proteins, giving higher molecular weights, and hence increased Rmax and stronger gluten. The two varieties differed in their response to temperature. In addition, there were seasonal variations in gluten functionality that may be associated with fluctuations in day temperatures between the seasons.  相似文献   

Intraspecies genetic variability of Ornithobacterium rhinotracheale in commercial birds in Peru     

Koga Y  Zavaleta AI 《Avian diseases》2005,49(1):108-111

Strains of the bacterium Ornithobacterium rhinotracheale (ORT), a causal agent of respiratory diseases in birds, were microbiologically isolated, identified, and molecularly characterized. Blood-enriched culture media and biochemistry tests were used for microbiologic identification. Polymerase chain reaction (PCR) and repetitive extragenic palindromic PCR (rep-PCR) techniques were used for molecular identification and characterization, respectively, of the microorganism. ORT strains were isolated in enriched media from the trachea and air sacs of broilers, breeders, and layers from several geographic zones of Peru. Of the original 75 strains isolated from 75 clinical samples from which ORT was recovered during 1998-2000, 25 were selected for further study based on ORT as the primary pathogenic isolate (no other pathogens were detected). Selected isolates were molecularly identified and characterized by PCR using specific primers designed from the conserved zones of the 16S ribosomal genes. Primers used for the identification of ORT produced a specific fragment of 784 base pair (bp), which did not appear in Haemophilus paragallinarum or Pasteurella multocida, microorganisms with similar morphologic and biochemical characteristics that produce dinical signs identical to those of ORT. All 25 strains of ORT tested with rep-PCR had a genetic profile similar to that of ORT American Type Culture Collection 51463, indicating the presence of only one genotype in the ORT strains studied.  相似文献   

Matrix metalloproteinases (MMPs) activity in cultured canine bone marrow stromal cells (BMSCs)     

Haraguchi T  Tani K  Koga M  Oda Y  Itamoto K  Yamamoto N  Terai S  Sakaida I  Nakazawa H  Taura Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2012,74(5):633-636

Autologous bone marrow stromal cells (BMSCs) infusion therapy improves the hepatic fibrosis. To investigate the mechanism of remission, we evaluated the matrix metalloproteinase (MMP)-2 and -9 activity in canine BMSCs and the effect of pro-inflammatory cytokines on their expression. The activity and the gene expression of MMPs were analyzed by gelatin zymography and quantitative RT-PCR, respectively. The specific gelatinase bands were indicative effect of MMP-2 and -9 in canine BMSCs. MMP-2 expression seemed to be increased by TNF-α and IL-1β while MMP-9 was enhanced by TNF-α and IL-6. These results suggested that remissive effect on liver fibrosis might be partly attributable to the MMP-2 and -9 activity in BMSCs under the inflammatory condition.  相似文献   

An effective approach to sustainable small-scale irrigation developments in Sub-Saharan Africa     

Michihiko Sakaki  Kiyoshi Koga 《Paddy and Water Environment》2013,11(1-4):1-14

Countries in Sub-Saharan Africa (SSA) that depend on foreign aid once political independence is gained, continue to be affected by changing aid modalities led by aid communities. It has been claimed that previous irrigation programs in SSA have not improved agricultural production as expected, and that the budget for implementation of further irrigation development has then been decreased. As a result, small-scale operations, which are part of participatory integrated rural development (PIRD), have become mainstream in the implementation of irrigation development in SSA. A small-scale irrigation development (SSID) was considered capable of attracting initial investment, required shorter construction periods, was comparatively easy to design, farmers were able to maintain the system themselves, and it had a lesser environmental impact. In general, to achieve a sustainable irrigation scheme, three systems must be established: a “water utilization system”; an “operation and maintenance (O&M) system”; and a “succession system”. This paper discusses SSID in SSA with regard to a number of important factors, i.e., environmental, economic, and social factors, all of which impact on the sustainability of SSID. The progress of low-input, effective, and sustainable irrigation development (LESID) and the impact of changing aid modalities is followed in three countries, Ghana, Malawi, and Tanzania. In addition, the future effective implementation of SSID by way of LESID in other SSA countries is discussed. A self-supported SSID (as employed in Malawi) is currently considered the most appropriate LESID for least developed countries (LDCs) in SSA.  相似文献   

Development of a real‐time PCR assay for detection and quantification of Streptococcus iniae using the lactate permease gene     

Yolanda Torres‐Corral  Ysabel Santos 《Journal of fish diseases》2021,44(1):53-61

The aim of this study is the development and evaluation of a rapid and accurate quantitative PCR (qPCR)‐based protocol for detection of zoonotic pathogen Streptococcus iniae in bacterial cultures and tissues of diseased fish. For this purpose, the lactate permease‐encoding (lldY) gene was selected as a target for the design of S. iniae‐specific primers based on comparative genomic analysis using 45 sequences retrieved from NCBI genome database. Specificity and applicability of these primers were tested using 115 bacterial strains and fish tissues infected with S. iniae. Sensitivity, reproducibility and efficiency of qPCR assay were also determined. The developed qPCR assay showed 100% specificity with pure bacterial cultures or DNA extracted from S. iniae or tissues of fish infected with the bacterium. The method has high sensitivity with a detection limit of 1.12 × 10¹ amplicon copies per assay (equivalent to 2 × 10^–9 ng/µl) using bacterial DNA and of 1.44 × 10¹ gene copies in tissues of fish infected with S. iniae. In conclusion, this qPCR protocol provides an accurate and sensitive alternative for the identification of S. iniae and its detection on fish tissues that can be implemented as a routine tool in microbiological laboratories.  相似文献   

Resistance in leaf blades assessed by counting conidia correlates with whole-plant-specific resistance in leaf sheaths in a compatible rice–Magnaporthe oryzae interaction     

Hironori Koga  Koji Dohi  Reiko Yoshimoto  Masashi Mori 《Journal of General Plant Pathology》2008,74(3):246-249

Resistance in the leaf blades of rice plants against a virulent race of the rice blast fungus Magnaporthe oryzae was quantitatively examined using a modified spot inoculation method. Numbers of conidia produced in the lesions were affected by plant age and paralleled the frequency of resistance infection types, which is indicative of whole-plant-specific resistance (WPSR), in the inoculated leaf sheaths of the corresponding plants. Exogenous abscisic acid treatment, which suppresses WPSR, also increased the susceptibility of the leaf blades. These results indicate a correlation between the resistance of the leaf blades and the WPSR in the leaf sheaths.  相似文献   

Factors contributing to the resistance of chickens to infection with Japanese Fasciola sp.     

J Kawano  M Koga  A Shimizu  S Kimura 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(1):75-79

Attempts were made to clarify the factors contributing to the resistance of chickens to infection with Japanese Fasciola sp. Infection was not successfully established in chickens by oral inoculation of metacercariae, nor by inoculation of excysted juvenile flukes into the body cavity or to the liver surface. Many metacercarial cysts were detected within two days in the feces of orally inoculated chickens. In the in vitro excystation test with chicken bile at 42 degrees C, metacercariae emerged successfully. These results indicate that the major resistant factors may not act during the migration from the mouth to the liver. Histopathological examination of the liver of experimental chickens could not prove the effect of a resistant factor. Excysted flukes were cultivated at 37-42 degrees C in RPMI1640 supplemented with calf serum, with the result that the survival rate of flukes fell with higher temperatures. When chicken serum was used instead of calf serum, flukes survived for a long period of time at 37 degrees C, while all died within four days at 42 degrees C. The higher body temperature of chickens than that of other mammalian hosts is considered to be the major factor contributing to the resistance of chickens to infection with Fasciola sp.  相似文献   

Effects of rumen‐protected methionine on milk production in early lactation dairy cattle fed with a diet containing 14.5% crude protein     

Tetsuo Tamura  Kazunori Inoue  Hideto Nishiki  Masafumi Sakata  Makoto Seki  Teruaki Koga  Yoshihiro Ookubo  Kazuhiro Akutsu  Say Sato  Kouichi Saitou  Hikari Shinohara  Terumi Kuraisi  Hiroshi Kajikawa  Mitsunori Kurihara 《Animal Science Journal》2019,90(1):62-70

We evaluated the influence on milk production of feeding early lactation cows a diet that included 14.5% crude protein (CP) and that did not meet methionine (Met) requirements or that met them by supplying rumen‐protected Met (RPMet). Thirty‐nine multiparous Holstein cows were allocated into two groups. For 15 weeks after calving, each group was fed one of the two total mixed rations, Control (n = 20) or Treatment (n = 19). The Treatment group received added RPMet at 0.034% (8 g/day) of the Control diet on dry matter basis. The adequacies of Met for the Control and Treatment groups were 96% and 106%, respectively, and for other amino acids, >110%. The CP level (14.5%) was 1 percentage point lower than that recommended by the Japanese Feeding Standard (2006). No between‐group differences were found in milk yield (40 kg/day), milk composition, plasma profile, rumen fermentation, nitrogen balance, or cow health. Met intake and the amount of rumen‐undegradable feed Met were higher in the Treatment group (p < 0.05). Microbial Met and total metabolizable Met did not differ between groups. Supplying RPMet in a 14.5% CP diet during early lactation did not dramatically affect milk production, because the amount of total metabolizable Met was unchanged.  相似文献