Influence of death struggle on the structural changes in chub mackerel muscle during chilled storage

ABSTRACT: Chub mackerel (34–35 cm, approximately 500 g), which were caught by fishing with a rod and line at the Bungo Channel, Oita prefecture, were rested overnight in a fish preserve and either killed by decapitation (control group) or allowed to struggle in air for 30 min (struggled group). Muscle samples were excised every 4 h, and measurements on breaking strength and histological observations were done for both groups. The breaking strength of muscle in the control group was significantly higher than that in the struggled group, whereby a decrease in breaking strength was delayed for 12 h compared to the struggled group. Light microscopy showed space extension among muscle cells in association with a decrease in breaking strength. Especially in the struggled group, the extended area was larger and the difference in area was significant at the time when breaking strength showed a significant difference. Using electron microscopy, the extended area showed cut and/or disappeared collagen fibrils. From these results, it was demonstrated that struggling to death promoted the degradation of collagen fibrils and the weakening of connective tissue and, resultantly, led to the faster softening of muscle of chub mackerel.     

Spinal epidural empyema concurrent with sequestrum in a cat: a case report

A 5-month-old intact female mixed cat presented with repetitive paraplegia and drainage of pus from the back despite continuous antibiotic medication. Neurologic examination was consistent with below T3-L3 myelopathy. Computed tomography and magnetic resonance imaging revealed a contrast-enhanced mass in the L1-3 spinal canal, and bone fragments in the T13 and L1 spinal canal. Spinal epidural empyema was suspected, and hemilaminectomy was performed for T12-L2 on the right side and T11-12 on the left side. Bone fragments were diagnosed as sequestrum infected with Bacteroides sp. The cat recovered enough to ambulate next day. One month after surgery, there was no deficit in neurological function. This is the first report of spinal epidural empyema concurrent with sequestrum in a cat.     

Effect of Amylose Content on Gelatinization,Retrogradation, and Pasting Properties of Starches from Waxy and Nonwaxy Wheat and Their F1 Seeds

We studied the effect of amylose content on the gelatinization, retrogradation, and pasting properties of starch using wheat starches differing in amylose content. Starches were isolated from waxy and nonwaxy wheat and reciprocal F1 seeds by crossing waxy and nonwaxy wheat. Mixing waxy and nonwaxy wheat starch produced a mixed starch with the same amylose content as F1 seeds for comparison. The amylose content of F1 seeds ranged between waxy and nonwaxy wheat. Nonwaxy‐waxy wheat had a higher amylose content than waxy‐nonwaxy wheat. Endothermic enthalpy and final gelatinization temperature measured by differential scanning calorimetry correlated negatively with amylose content. Gelatinization onset and peak temperature clearly differed between F1 and mixed starches with the same amylose content as F1 starches. Enthalpy for melting recrystallized starches correlated negatively with amylose content. Rapid Visco Analyser measurement showed that F1 starches had a higher peak viscosity than waxy and nonwaxy wheat starches. Mixed starches showed characteristic profiles with two low peaks. Setback and final viscosity correlated highly with amylose content. Some of gelatinization and pasting properties differed between F1 starches and mixed starches.     

旱稻水分利用率与碳同位素识别值之间的关系

通过温室盆栽试验 ,分析和探讨了三个水平的土壤水分条件对分蘖期和成熟期收获的旱稻(OryzasativaL .)生物量累积、水分利用率 (WUE)、植株不同部位的碳同位素识别值 (CID)的影响 ,并了解了它们之间的相互关系。水分条件包括 :饱和含水量 (W1 )、饱和含水量的 70 %(W2 )、饱和含水量的 4 0 %(W3)。结果表明当土壤水分条件从W1降低到W2时 ,分蘖期收获的生物量降低 4 5 %左右 ,成熟期收获的生物量降低 1 6 %～ 1 9%;而当从W1降低到W3时 ,分蘖期收获的生物量降低 73%左右 ,成熟期收获的生物量降低 5 5 %～ 5 7%。然而 ,根据地上部干重计算而来的WUE(WUE 地上部 )和根据全株干重计算而来的WUE(WUE 全株 )则随土壤含水量的降低而增加 ,其增幅在分蘖期为 0 .0 7～ 0 .2 8gkg-1 ,在成熟期为 0 .0 7～ 0 .4 5gkg-1 。植株的CID值变幅为 1 7.0～ 2 0 .6 ,但植株不同部位间差别显著 ,分蘖期收获的样品CID值从小到大的顺序为 :根 <最近完全伸展叶 <叶芽 <茎秆 ;而成熟期收获的样品CID值从小到大的顺序为 :籽粒 <根 <茎秆 <旗叶。随着土壤含水量的降低 ,植株所有部位的CID值亦显著减小。叶部的CID值与WUE 地上部(和WUE 全株 )之间呈一致的负相关关系。     

Successful induction of lactation in a barren thoroughbred mare: growth of a foal raised on induced lactation and the corresponding maternal hormone profiles

The purpose of this study was to demonstrate that a barren parous Thoroughbred mare with lactation induced by hormonal treatment can be introduced to an orphan foal at the same farm and that the mare can become pregnant after the end of the hormonal treatment. An additional purpose was to investigate the changes in the plasma concentrations of prolactin, estradiol-17β, progesterone, follicle-stimulating hormone, and luteinizing hormone before, during, and after hormonal treatment. The difference in body weight between the adopted foal and the control foals, which were at the same farm and raised by their natural mothers, was 17 kg at 24 weeks old, when the foals were weaned. However, the adopted foal and the control foals had almost the same weight at 35 weeks old and later. The first ovulation after hormonal treatment was confirmed 10 days after the end of hormonal treatment and then the normal estrous cycle resumed. Furthermore, the changes in plasma progesterone, estradiol-17β, follicle-stimulating hormone, and luteinizing hormone showed regular patterns after the first ovulation. Conception was confirmed in the fifth ovulation. Meanwhile, another study demonstrated that conception was confirmed in the first ovulation after hormonal treatment. The present study is the first to demonstrate the hormonal profiles during and after induction of lactation in a Thoroughbred mare. This approach is useful for solving the economic and epidemic problems of introducing a nurse mare to an orphan foal.     

Use of tween 20 as a substrate for assay of lipase activity in soils

Abstract

A method for assaying the soil lipase activity is described. It involves the titrimetric estimation of the amount of lauric acid released by the lipase activity when the soil is incubated with Tween 20 in the presence of toluene at 30°C for 18 h under agitation. The method is simple and precise and incubation without agitation is also possible. The method has been applied to six different kinds of soils. The lipase activity in the cultivated soils ranged from 22.5 to 75.5 mmol min^?1 g^?1 of dried soil. The K _m value for Tween 20 was 1.8 × 10^?4 m. The optimum pH was approximately 7.5. The hydrolysis of liveen 20 in soil was inhibited by glycerol which was the essential moiety of glyceride. The inhibition by glycerol was found to be competitive. These results indicate that Tween 20 is a potential substrate for the assay of the glyceride hydrolytic activity in soils.     

Differences in oxygen and carbon stable isotope ratios between hatchery and wild pink salmon fry

We examined differences in otolith oxygen (δ¹⁸O_otolith) and carbon (δ¹³C_otolith) stable isotope ratios between hatchery and wild pink salmon fry. The δ¹⁸O_otolith values of hatchery and wild fry were ?7.7 ± 0.2 ‰ and ?8.3 ± 0.3 ‰ (1σ), respectively. This difference reflected differences in temperature conditions experienced by each fry. The δ¹³C_otolith values of hatchery and wild fry were ?19.2 ± 0.3 ‰ and ?11.1 ± 1.8 ‰ (1σ), respectively. The lower δ¹³C_otolith values of hatchery fry were probably related to their intake of artificial diets. Discriminant analysis of δ¹⁸O_otolith and δ¹³C_otolith values demonstrated a highly significant difference between hatchery and wild fry with 95.8 % classification accuracy. Therefore, analysis of δ¹⁸O_otolith and δ¹³C_otolith precipitated in the fry stage may be useful for discriminating the origin of returning adult pink salmon. The discrimination method for returning adult fish would provide important information for evaluating the effect of hatchery release and their impact on the wild population.     

Evaluation of coral bleaching condition <Emphasis Type="Italic">in situ</Emphasis> using an underwater pulse amplitude modulated fluorometer

ABSTRACT:   Photosynthetic activities of hermatypic corals (28 genera, c . 68 species and c. 92 specimen) were measured in November 2000 at Sekisei lagoon, Okinawa, Japan, using an underwater pulse amplitude modulated fluorometer. Maximum quantum yield (Fv/Fm) ranged from 0.61 to 0.70 and had an average value of 0.664 (standard deviation [SD], 0.0289). Following the measurement of Fv/Fm, quantum yield (Fm'-F)/Fm' at eight-leveled actinic-light intensities were obtained from all specimens. Values of electronic transport rates (ETR) were nearly the same under low photosynthetic active radiation (PAR; µmol quanta/m² per s) condition and varied with increasing PAR. The value of ETR at 100 µmol quanta/m² per s ranged from 21.3 to 30.0 and had an average of 27.8 (SD, 2.09). In August 2001, a coral bleaching event was observed in Sekisei Lagoon. During the event, photosynthetic activities of 21 specimens of eight species (seven genera) were measured. By applying two indicators, Fv/Fm and ETR at 100 µmol quanta/m² per s obtained in August 2000, 18 of 21 specimens were suggested under the bleaching process. In case of Porites lutea , seven colonies were visually evaluated for their condition of bleaching and were found to have two 'normal', three 'slightly bleached' and two 'heavily bleached'. From the density of zooxanthellae, colonies evaluated 'normal' or 'slightly bleached' did not show an apparent difference. However, they were clearly identified by Fm/Fv and ETR at 100 µmol quanta/m² per s.     

Nutrient requirement for zoospore formation in two alariaceous plants Undaria pinnatifida (Harvey) Suringar and Alaria crassifolia Kjellman (Phaeophyceae: Laminariales)

ABSTRACT:   Sporophyll formation in two alariaceous plants, Undaria pinnatifida and Alaria crassifolia , was studied in relation to the nutrient requirements. The sporophylls of U. pinnatifida formed zoosporangia when they had N and P contents greater than 1.4 kgN/m³ and 0.74 kgP/m³. This indicates that these values are the critical nutrient levels for zoospore formation in U. pinnatifida . In the sporophytes of A. crassifolia , many sporophylls with zoosporangia showed nutrient contents higher than 6.25 kgN/m³ and 1.70 kgP/m³. These results suggest that the U. pinnatifida can form zoospores at lower levels of N and P contents than A. crassifolia . Both species often formed zoosporangial sori on the blades in the late period of each reproductive season. The fertile parts of the blade showed N and P contents higher than the critical levels. This phenomenon indicates that the blades have the capability to form zoosporangial sori if there is a sufficient accumulation of nutrients for zoospore formation. The zoospore formation on the blade seems to be accomplished by an overflow of excess nutrients from sporophylls into the blade, or by accumulating sufficient nutrients to form sori even if the sporophylls are not formed.     

Hardness distribution on wood surface

For better understanding wood hardness, we developed a new hand-operated hardness tester that works with Brinell's method. With this tester we investigated the hardness distribution of wood minutely using a 2mm diameter ball tip. The following results were obtained: (1) On preliminary examination with medium-density fiberboard, we found that the value of Brinell's hardness decreased with the increase in the tip ball's diameter but that it was almost constant with the indenting velocity. (2) By using a small diameter tip, the difference of the hardness became clearer between earlywood and latewood. (3) With radial and tangential sections, we obtained hardness distribution patterns similar to those of wood grain. It seems that the hardness distribution reflects the distribution of density on wood surfaces.