Characterization of structure and function of the mouse retina using pattern electroretinography, pupil light reflex, and optical coherence tomography     

Mohan K  Harper MM  Kecova H  Ye EA  Lazic T  Sakaguchi DS  Kardon RH  Grozdanic SD;CR: BioMed Vision Technologies  Neuroptics Inc 《Veterinary ophthalmology》2012,15(Z2):94-104

Objective To perform in vivo analysis of retinal functional and structural parameters in healthy mouse eyes. Animal Studied Adult C57BL/6 male mice (n?=?37). Procedures Retinal function was evaluated using pattern electroretinography (pERG) and the chromatic pupil light reflex (cPLR). Structural properties of the retina and nerve fiber layer (NFL) were evaluated using spectral-domain optical coherence tomography (SD-OCT). Results The average pERG amplitudes were found to be 11.2?±?0.7?μV (P50-N95, mean?±?SEM), with an implicit time for P50-N95 interval of 90.4?±?5.4?ms. Total retinal thickness was 229.5?±?1.7?μm (mean?±?SEM) in the area centralis region. The thickness of the retinal nerve fiber layer (mean?±?SEM) using a circular peripapillary retinal scan centered on the optic nerve was 46.7?±?0.9?μm (temporal), 46.1?±?0.9?μm (superior), 45.8?±?0.9?μm (nasal), and 48.4?±?1?μm (inferior). The baseline pupil diameter was 2.1?±?0.05?mm in darkness, and 1.1?±?0.05 and 0.56?±?0.03?mm after stimulation with red (630?nm, luminance 200?kcd/m(2) ) or blue (480?nm, luminance 200?kcd/m(2) ) light illumination, respectively. Conclusions Pattern electroretinography, cPLR and SD-OCT analysis are reproducible techniques, which can provide important information about retinal and optic nerve function and structure in mice.  相似文献   

Heat pipe phenomenon in soil under reduced air pressure     

I. Sakaguchi  T. Momose    H. Mochizuki  & T. Kasubuchi 《European Journal of Soil Science》2009,60(1):110-115

We measured the heat flux, temperature distribution and water content of an unsaturated Ando soil under a constant temperature gradient and reduced air pressure to investigate the mechanism of latent heat transfer in the soil and its relationship to the distribution and circulation of soil water. As the air pressure decreased, the heat flux increased for the soil samples with an initial volumetric water content ( θ _ini) greater than 0.30 m³ m⁻³, but did not change for θ _ini less than 0.20. While the temperature gradient of the sample did not change for θ _ini greater than 0.30 m³ m⁻³, it did increase on the hotter side of the sample and decreased on the colder side for θ _ini less than 0.20. The water content did not change, and a homogeneous distribution of water content was observed for θ _ini greater than 0.30 m³ m⁻³. For θ _ini less than 0.20, the water content decreased on the hotter side and increased on the colder side, forming a large water content gradient. The large transfer of latent heat was caused by the circulation of water vapour and liquid water, which resulted in the homogeneous water distribution. We concluded that the soil functions as a heat pipe through a series of micro-heat pipes centred on the soil pores. Our experimental results will help to explain the transfer mechanism of latent heat in soil as a heat pipe phenomenon.  相似文献   

Antifungal activity of a novel compound purified from the culture filtrate of <Emphasis Type="Italic">Biscogniauxia</Emphasis> sp. O821 against the rice blast fungus <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis>     

Quyet Thi Nguyen  Kana Ueda  Tomoko Tamura  Junichi Kihara  Kazuhito Itoh  Keisuke Yoshikiyo  Yoshimitsu Sakaguchi  Makoto Ueno 《Journal of General Plant Pathology》2018,84(2):142-147

Rice blast is a devastating fungal disease resulting in major losses to rice crops. Owing to continuous acquisition of resistance by the causal fungus, several fungicide chemicals are no longer effective. Therefore, there is a need to identify natural components and develop new agents to control fungal pathogens. We previously demonstrated that the culture filtrate of Biscogniauxia sp. O821 inhibited infection behavior of Magnaporthe oryzae and subsequent blast lesion formation. In the present study, we isolated a new compound, (3aS,4aR,8aS,9aR)-3a-hydroxy-8a-methyl-3,5-dimethylenedecahydronaphto[2,3-b]furan-2(3H)-one (HDFO), from the culture filtrate of Biscogniauxia sp. O821 and determined its molecular weight as 248. The HDFO structure was determined by electrospray ionization-mass spectrometry and nuclear magnetic resonance spectroscopy after purification with column chromatography and high-performance liquid chromatography. The structure of this antifungal compound was similar to that of alantolactone and isoalantolactone. The growth inhibition zone against M. oryzae in presence of HDFO was observed at Rf 0.5–0.6 on a thin layer chromatography plate. HDFO inhibited conidial germination of M. oryzae in a dose-dependent manner (1–200 ppm). Furthermore, blast lesion formation was significantly suppressed by HDFO at over 5 ppm. These results suggest that HDFO from the culture filtrate of Biscogniauxia sp. O821 can protect rice from rice blast disease caused by M. oryzae. This is the first report that HDFO produced by Biscogniauxia sp. can serve as an antifungal compound against M. oryzae.  相似文献   

Implication of coprophagy in pathogenesis of chicken botulism     

S H Hyun  G Sakaguchi 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1989,51(3):582-586

Oral administration of 1 x 10(7) viable spores of Clostridium botulinum type C killed the chickens kept on a board floor to allow them coprophagy, whereas the same dose of the spores failed to develop symptoms in those kept on a wire-net floor not to allow them coprophagy. Type C toxin was detected in the cecal droppings of the chickens of both the groups after feeding the spores and also in serum of symptomatic as well as asymptomatic chickens kept on a board floor. Thus, coprophagy, by which chickens ingest type C toxin (C1 L toxin) and the bacterial cells, seems to be a prerequisite for development of chicken botulism.  相似文献   

Correlations of the electrophysiological activity of neonicotinoids with their binding and insecticidal activities     

Nishiwaki H  Nakagawa Y  Kuwamura M  Sato K  Akamatsu M  Matsuda K  Komai K  Miyagawa H 《Pest management science》2003,59(9):1023-1030

The electrophysiological actions of various neonicotinoids, including substituted benzyl derivatives, against recombinant Drosophila SAD/chicken beta2 hybrid nicotinic acetylcholine receptor (nAChR) were measured to analyze the relationships between the in vivo (insecticidal) and in vitro (binding and agonist) activities. Most of the neonicotinoids tested were capable of inducing inward currents by activating the hybrid nAChRs expressed in Xenopus laevis oocytes, whereas some compounds had no agonist activity and only blocked the acetylcholine-induced currents. Variations in the agonist activity were well correlated with those in the binding potency evaluated using [3H]imidacloprid as well as insecticidal activities.  相似文献   

IgE sensitivity and cross-reactivity to crude and purified mite allergens (Der f 1, Der f 2, Der p 1, Der p 2) in atopic dogs sensitive to Dermatophagoides mite allergens     

Masuda K  Tsujimoto H  Fujiwara S  Kurata K  Hasegawa A  Yasueda H  Yamashita K  DeBoer DJ  de Weck AL  Sakaguchi M 《Veterinary immunology and immunopathology》1999,72(3-4):303-313

The present study investigates IgE-reactivity to crude and purified mite allergens by intradermal skin test (IDST), Immunodot method, and ELISA in atopic dogs sensitive to mite allergens, as well as the allergenic cross-reactivity between Dermatophgoides (D) farinae (DF) and D. pteronyssinus (DP) in dogs by IgE-ELISA inhibition. IDST and Immunodot method for crude mite allergens were performed for atopic dogs and 16 atopic dogs showed sensitivity to mite allergens. Of the 16 dogs, all dogs had anti-DF IgE and 11 had anti-DP IgE. We measured specific IgE to purified major allergens (Der f 1, Der f 2, Der p 1, Der p 2). Of the 16 atopic dogs, six had anti-Der f 1 IgE and seven had anti-Der f 2 IgE. Similarly, of the 16 dogs, six had anti-Der p 1 IgE and seven had anti-Der p 2 IgE. However, eight dogs had no specific IgE to these mite allergens. These dogs may be sensitive to other major mite allergens except Der 1 and Der 2. In the dogs that had both anti-DF and DP IgE, IgE binding to DF was greatly inhibited by DP, and reciprocal inhibition was observed. Based on these data, it appears that there is a strong cross-reactivity between DF and DP in dogs. Similarly, a cross-reactivity between DF and DP in purified allergens was also observed. IDST and Immunodot method are useful methods for the diagnosis of atopic diseases in dogs, and ELISA is a useful method for further investigation of IgE-reactivity for the allergens.  相似文献   

Destruction of salmonellae, Escherichia coli, and Staphylococcus aureus inoculated into and onto beef during dry-oven roasting     

T Shigehisa  T Nakagami  S Taji  G Sakaguchi 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1985,47(2):251-257

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Transfer of blood urea nitrogen to cecal microbial nitrogen is increased by fructo‐oligosaccharide feeding in guinea pigs          下载免费PDF全文

Kiyonori Kawasaki  Xiao Min  Xiao Li  Ena Hasegawa  Ei Sakaguchi 《Animal Science Journal》2015,86(1):77-82

The present study was conducted to determine the mechanism by which nitrogen (N) availability is improved by fructo‐oligosaccharide (FOS) in guinea pigs. Adult male guinea pigs were fed a commercial pellet diet (50 g/day) with either 5% glucose or 5% FOS for 7 days in individual metabolism cages. After 7 days of feeding the diet, ¹⁵N‐urea was administered intravenously 1 h before slaughter under anesthesia. The amount and concentration of total, protein, bacterial, ammonia and urea N and the ¹⁵N atom % excess were measured in blood, liver, gut contents and urine. The ¹⁵N atom % excess of total and protein N, and the amount of total, protein and bacteria N and ¹⁵N in the cecum were significantly increased by the consumption of FOS. Furthermore, the concentration and amount of short‐chain fatty acids were significantly increased by the consumption of FOS. In contrast, the amount of urinary ¹⁵N was significantly decreased by the consumption of FOS. These results suggest that consumption of FOS increases transfer of blood urea N into the large intestine for bacterial N synthesis, which is subsequently re‐absorbed by cecotrophy, and contributes to the increase of N utilization in guinea pigs.  相似文献   

Reliability of estrous detection in Holstein heifers using a radiotelemetric pedometer located on the neck or legs under different rearing conditions     

Sakaguchi M  Fujiki R  Yabuuchi K  Takahashi Y  Aoki M 《The Journal of reproduction and development》2007,53(4):819-828

To evaluate the efficiency and accuracy of estrous detection using a new pedometry system that can measure the hourly activity of cattle, pedometers were attached to the neck and the hind legs of 15 Holstein heifers. Heifers were reared in pasture for grazing, an open paddock, or in a tie-stall barn (an additional pedometer was attached to a front leg of each of these heifers). The most recent 24 h-total number of steps was compared for each 1 h-interval with the mean value of the preceding days during the reference period (RP). The neck pedometer detected all 10 instances of estrous activity (100%) for the grazing heifers at 1.3 times the thresholds value for a 5-day RP but with only 32% accuracy. The hind leg pedometer, however, obtained 100% efficiency and 83% accuracy at 1.4 times the threshold value for a 7-day RP. The efficiencies and accuracies in detecting 12 instances of estrous activity under the paddock condition were 92 and 65% (neck, 1.3-fold, 7-day RP) and 92 and 100% (hind leg, 1.6- or 1.7-fold, 7-day RP), respectively. Under the tie stall condition, the neck pedometers detected 92% of 23 instances of estrous activity with 34% accuracy (1.2-fold, 3-day RP), and the efficiencies and accuracies of the leg pedometers were 78 and 78% (hind leg, 1.4-fold, 4- or 6-day RP) and 87 and 83% (front leg, 1.4-fold, 7-day RP), respectively. Prediction of ovulation time was more precisely with the leg pedometers than with those under the tie stall conditions. Our preliminary results indicate that this new pedometer system has practical value for estrous detection in heifers under different rearing conditions, which affect the criteria required for detection. Furthermore, they also indicate that a leg pedometer can reliably detect estrus and that a neck pedometer may only be capable of detecting estrus under paddock rearing conditions.  相似文献   

Morphological identity of a taxonomically unassigned cytochrome c oxidase subunit I sequence from stomach contents of juvenile chum salmon determined using polymerase chain reaction     

Sakiko Orui Sakaguchi  Tetsuro Ikuta  Gen Ogawa  Kodai Yamane  Naonobu Shiga  Hiroshi Kitazato  Katsunori Fujikura  Kiyotaka Takishita 《Fisheries Science》2017,83(5):757-765

In a previous report, we analyzed the stomach contents of juvenile chum salmon Oncorhynchus keta by morphological observation and also by molecular identification using the mitochondrial cytochrome c oxidase subunit I (COI) region. However, one of the most frequently detected COI sequences could not be assigned to any specific taxon, even at the phylum level. In the present study, we conducted in situ hybridization (ISH) on the stomach contents of juvenile chum salmon using the COI sequence and polymerase chain reaction amplification of a 18S ribosomal RNA gene from the tissue sections where ISH signals were detected. As a result, the organism that was enigmatic at the phylum level was found to be an appendicularian. Moreover, Oikopleura longicauda collected from the bay where the juvenile chum salmon samples were obtained was shown to have the same COI sequences as this taxonomic “orphan” COI sequence from the stomach contents. The present results suggest that the COI sequences previously deposited in public databases for “Oikopleura” are actually derived from taxonomic groups other than appendicularians, and that this may have hampered our understanding of prey richness in the stomach or gut of certain marine animals based on DNA barcoding.  相似文献