Net depth response of a depth-controllable (towed) gillnet for fish sampling     

Daisuke Shiode  Yasuzumi Fujimori  Fuxiang Hu  Susumu Shimizu  Teisuke Miura 《Fisheries Science》2001,67(1):110-117

SUMMARY: Flume-tank experiments were performed to examine the depth response of a new type of depth-controlled gillnet. Variations of net depth were investigated as the warp was paid out and wound up for different changes of warp length, main sinker weights, and winch speeds. In most experiments, when the warp finished paying out, the net continued to descend and then ascended slightly to an equilibrium depth (overshoot phenomenon). The overshoot distance was nearly constant when the warp was wound up and increased linearly with increasing winch speed when the warp was paid out. An increase in winch speed reduced net settling time, which converged on a constant value for both paying out and winding up.  相似文献   

Screening of an allelopathic potential in arbor species     

SAYAKA MORITA  MIHO ITO  JIRO HARADA 《Weed Biology and Management》2005,5(1):26-30

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Seasonal pattern of shoot emergence and its endogenous control in horsenettle (Solanum carolinense L.)     

KATSURA MIYAZAKI  MISAKO ITO  SHUJI URAKAWA 《Weed Biology and Management》2005,5(1):14-18

Controlling established horsenettle plants is achieved by suppressing shoot emergence from root systems. The seasonal pattern of shoot emergence and its possible endogenous control in horsenettle ( Solanum carolinense L.) were investigated. The shoot emergence period in an undisturbed population was limited to a seven-week period from mid-April, and a little longer in tilled conditions. Detached roots showed very high shoot-sprouting ability under 15–30°C throughout the year. In shoot clipping experiments, new shoots sprouted only from the stem and not from the root when attached to shoots, whether above-ground or underground. On the contrary, new shoots sprouted from the roots when all parts of the shoots were clipped off. From these results, the limited shoot emergence period in horsenettle is thought to be initiated by temperatures necessary for sprouting and is ended by a growth correlation effect between early emerged and matured shoots.  相似文献   

Catalog of Micro-Tom tomato responses to common fungal, bacterial, and viral pathogens     

Hideki Takahashi  Ayano Shimizu  Tsutomu Arie  Syofi Rosmalawati  Sumire Fukushima  Mari Kikuchi  Yasufumi Hikichi  Ayami Kanda  Akiko Takahashi  Akinori Kiba  Kohei Ohnishi  Yuki Ichinose  Fumiko Taguchi  Chihiro Yasuda  Motoichiro Kodama  Mayumi Egusa  Chikara Masuta  Hiroyuki Sawada  Daisuke Shibata  Koichi Hori  Yuichiro Watanabe 《Journal of General Plant Pathology》2005,71(1):8-22

Lycopersicon esculentum cultivar Micro-Tom is a miniature tomato with many advantages for studies of the molecular biology and physiology of plants. To evaluate the suitability of Micro-Tom as a host plant for the study of pathogenesis, Micro-Tom plants were inoculated with 16 well-known fungal, bacterial, and viral pathogens of tomato. Athelia rolfsii, Botryotinia fuckeliana, Oidium sp., Phytophthora infestans, and Sclerotinia sclerotiorum caused typical symptoms and sporulated abundantly on Micro-Tom. Micro-Tom was resistant to Alternaria alternata, Corynespora cassiicola, and Fusarium oxysporum. When Micro-Tom was inoculated with 17 isolates of Ralstonia solanacearum, many isolates induced wilt symptoms. Agrobacterium tumefaciens also was pathogenic, causing crown galls on stem tissue after needle prick inoculation. In Micro-Tom sprayed with Pseudomonas syringae pv. tomato, P. s. pv. tabaci, or P. s. pv. glycinea, bacterial populations did not increase, and yellow lesions appeared only on leaves sprayed with P. s. pv. tomato. Tomato mosaic virus, Tomato aspermy virus, and Cucumber mosaic virus systemically infected Micro-Tom, which developed symptoms characteristic of other cultivars of tomato after infection with the respective virus. These results indicated that Micro-Tom was generally susceptible to most of the important tomato pathogens and developed typical symptoms, whereas certain pathogens were restricted by either hypersensitive resistance or nonhost resistance on Micro-Tom. Therefore, an assortment of Micro-Tom–pathogen systems should provide excellent models for studying the mechanism of susceptible and resistant interactions between plants and pathogens.  相似文献   

Single oral β-cryptoxanthin administration increases its serum concentration and enhances peripheral blood neutrophil function in Holstein cattle     

Atsushi KIMURA  Yo-Han KIM  Kazuyoshi HASHIZUME  Akira ITO  Katsuyuki MUKAI  Keiichiro KIZAKI  Shigeru SATO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(5):829

We investigated the effect of oral administration of β-cryptoxanthin (β-CRX) on its serum concentration and peripheral neutrophil functions by the chemiluminescence (CL) response in Holstein cattle. A single oral administration of β-CRX was performed for serum β-CRX concentration (0, 0.05, 0.1, or 0.2 mg/kg body weight [BW]) and for peak CL response of peripheral neutrophils (0.2 mg/kg BW). The serum β-CRX concentration was peaked on 2 days after, similar to peak CL response on 3 days after β-CRX administration. Therefore, a single oral administration of β-CRX (0.2 mg/kg BW) induces higher serum concentration and concurrently enhances bactericidal ability of peripheral neutrophils in Holstein cattle.  相似文献   

Effects of leptin and tumor necrosis factor-alpha on degranulation and superoxide production of polymorphonuclear neutrophils from Holstein cows     

Ahmed M  Kimura K  Soliman M  Yamaji D  Okamatsu-Ogura Y  Makondo K  Inanami O  Saito M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(2):125-131

Leptin, a pleiotropic hormone regulating food intake and energy expenditure, has been shown to directly modulate human polymorphonuclear neutrophil (PMN) functions or indirectly through the action of tumor necrosis factor-alpha (TNF-alpha). Bovine PMN have considerable different characteristics from human PMN. For example, it does not respond to N-formyl-Methionyl-Leucyl-phenylalanine, a well known human PMN activator. In the present study, we tested the effects of leptin and TNF-alpha on superoxide production and degranulation of bovine peripheral PMN, in which both long isoform of leptin receptor (Ob-Rb) and TNF receptor 1 were expressed. Human leptin, human TNF-alpha, phorbol myristate acetate (PMA) and opsonized zymosan particles (OZP) did not stimulate degranulation responses, while zymosan-activated serum (ZAS) did. Neither leptin nor TNF-alpha enhanced the ZAS-induced degranulation responses. TNF-alpha, PMA, OZP and ZAS increased superoxide production in different magnitudes, whereas leptin did not. TNF-alpha, but not leptin, enhanced OZP- and ZAS-induced superoxide production, possibly, in part due to facilitating translocation of p47(phox), a component of NADPH oxidase. These results indicate that, unlike in human PMN, leptin does not have any direct effect on degranulation and superoxide production in bovine PMN, although TNF-alpha influences superoxide production.  相似文献   

断奶后多系统衰竭综合征病猪中存在沙门氏菌和猪繁殖与呼吸系统综合征病毒共感染     

Akihiro O GAWA  Noriko ITO  Takashi NAKANE  魏晓锋  李春华 《国外畜牧学(猪与禽)》2007,27(1):46-48

调查了曾经暴发沙门氏菌病的四个猪场的14头病猪,发现在这些猪的肿胀淋巴结中出现带有淋巴细胞排空的肉芽肿性炎症。应用免疫标记和PCR方法在病变部位检测到猪圆环病毒2(PCV2)抗原和PCV2DNA。此外,在这些病猪的肺脏中检测出猪繁殖与呼吸综合征病毒(PRRSV),分离到猪霍乱沙门氏菌。在9头沙门氏菌感染猪中,有5头为沙门氏菌、PMWS与PRRSV并发感染,其数量(55.6%)远远高于沙门氏菌与PMWS感染猪(22.2%)或沙门氏菌与PRRSV感染猪(22.2%)。  相似文献   

Development of a plant conveyance system using an AGV and a self-designed plant-handling device: A case study of DIY plant phenotyping     

Takanari Tanabata  Kunihiro Kodama  Takuyu Hashiguchi  Daisuke Inomata  Hidenori Tanaka  Sachiko Isobe 《Breeding Science》2022,72(1):85

Plant phenotyping technology has been actively developed in recent years, but the introduction of these technologies into the field of agronomic research has not progressed as expected, in part due to the need for flexibility and low cost. “DIY” (Do It Yourself) methodologies are an efficient way to overcome such obstacles. Devices with modular functionality are critical to DIY experimentation, allowing researchers flexibility of design. In this study, we developed a plant conveyance system using a commercial AGV (Automated Guided Vehicle) as a case study of DIY plant phenotyping. The convey module consists of two devices, a running device and a plant-handling device. The running device was developed based on a commercial AGV Kit. The plant-handling device, plant stands, and pot attachments were originally designed and fabricated by us and our associates. Software was also developed for connecting the devices and operating the system. The run route was set with magnetic tape, which can be easily changed or rerouted. Our plant delivery system was developed with low cost and having high flexibility, as a unit that can contribute to others’ DIY’ plant research efforts as well as our own. It is expected that the developed devices will contribute to diverse phenotype observations of plants in the greenhouse as well as to other important functions in plant breeding and agricultural production.  相似文献   

The significance of meandering channel morphology on the diversity and abundance of macroinvertebrates in a lowland river in Japan     

Daisuke Nakano  Futoshi Nakamura 《水产资源保护:海洋与淡水生态系统》2008,18(5):780-798

• 1. Many rivers and streams across the world have been channelized for various purposes. Channel cross‐sections of meandering rivers are asymmetrical and have cross‐sectional diversity in their physical environment; cross‐sections of a channelized river are typically trapezoidal and have little cross‐sectional diversity, both in physical and ecological conditions. Several programmes to restore stream meanders have been undertaken to improve river ecosystems degraded by channelization. However, the association between diversification in the physical environment due to meander restoration and the macroinvertebrate community structure is poorly known.
• 2. This study of a lowland river in Japan assessed how the cross‐sectional diversity of the physical environment changed with restoration of a meander in a channelized river, and how the macroinvertebrate communities responded to the changes in physical habitat variation. Comparisons were made between the macroinvertebrate communities of a channelized reach, the restored meandering reach, and a natural meandering reach.
• 3. Natural meandering and restored meandering reaches showed higher cross‐sectional diversity in physical variables and total taxon richness across a reach than did the channelized reach. Almost all taxa observed in the natural and restored meandering reaches were concentrated in the shallowest marginal habitats near the banks. Shear velocity increasing with water depth had a negative association with macroinvertebrate density and richness.
• 4. This study demonstrated that the shallow river bed along the inside of bends formed point bars that provided a highly stable substrate, a suitable habitat for macroinvertebrates in a lowland river. It is concluded that meander restoration could be an effective strategy for in‐stream habitat restoration in lowland meandering rivers.

Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Life-history variation in relation to nest site abundance in males of the freshwater goby Tridentiger brevispinis     

Daisuke Takahashi 《Ecology of Freshwater Fish》2008,17(1):71-77

Abstract –  Age at maturity in males of the freshwater goby Tridentiger brevispinis , a species with exclusive paternal care, was investigated in two populations in Lake Biwa, Japan, that differed markedly in nest site abundance. At Ohmi-maiko, where nest sites were scarce, most males matured at age 3, and mean body size of males guarding eggs in nests was larger than that of males sampled randomly (including both guarding and nonguarding males) in the population. Conversely, at Minamihama, where nest sites were abundant, many males matured at age 1, and there was no difference in body size between guarding males and males collected randomly. The slope of regression lines between body size of the guarding male and the number of eggs in his nest was greater in Ohmi-maiko than in Minamihama. These results suggest that the shortage of nest sites enhances reproductive success in larger males, probably through male–male competition for nest sites and female mate choice for larger males. I conclude that in nest spawners, the availability of nest sites should strongly affect life-history traits of males through sexual selection.  相似文献