Control of dissolved oxygen levels of water in net pens for fish farming by a microscopic bubble generating system     

Sarawut Srithongouthai  Akira Endo  Akihiro Inoue  Kyoko Kinoshita  Miho Yoshioka  Ayako Sato  Takaaki Iwasaki  Ichiro Teshiba  Hisatsune Nashiki  Daigo Hama  Hiroaki Tsutsumi 《Fisheries Science》2006,72(3):485-493

ABSTRACT:   A microscopic bubble generating system (MBGS) has been developed to control dissolved oxygen (DO) levels suitable for fish farming. The MBGS has been tested to confirm its capability in net pens. Water conditions in a fish farm were monitored every two hours from June to October 2004 by setting an online vertical profiling system (OVPS) close to the net pen. DO in the net pen water decreased to physiologically stressful levels for the fish during the night (4.84–5.51 mg/L), while the DO was kept in saturated conditions during the day, due to oxygen supply from phytoplankton. The MBGS was operated from the evening to the morning of the next day for 16 h, to successfully create DO-saturated conditions in the net pen water at night. By using microscopic bubbles during the warm seasons, DO levels in the net pen water could be improved to a level suitable for fish farming. However, the low DO levels (<5.0 mg/L) of the bottom water occasionally extended to the net pen layers, despite the supply of microscopic bubbles to the water. To maintain the DO of the net pen water at levels suitable for fish farming, DO supply to the net pen water and the bottom water needs to be increased, and the organically enriched sediment just below the net pens needs to be treated.  相似文献   

Alanine racemase activity in the microalga <Emphasis Type="Italic">thalassiosira</Emphasis> sp.     

Takehiko?Yokoyama  Yumiko?Tanaka  Minoru?Sato  Nobuhiro?Kan-No  Toshiki?Nakano  Toshiyasu?Yamaguchi  Eizoh?NagahisaEmail author 《Fisheries Science》2005,71(4):924-930

ABSTRACT:   In this paper, the authors report the detection of alanine racemase activity in the marine diatom Thalassiosira sp. Since the Thalassiosira sp. was cultured under germ-free conditions, it appeared that D-alanine was not derived from bacteria but was produced through catalysis by algal alanine racemase. The rate of conversion of L-alanine to D-alanine was approximately the same as that for the reverse reaction, and the enzyme catalyzed the equilibration of the D- and L-forms. The crude enzyme preparation obtained from the cells at the stationary phase of the growth cycle had an optimal pH of approximately 9.5. The Lineweaver–Burk analysis showed that the K _m for D- and L-alanine was 16.5 mM and 29.4 mM, respectively. It appears that the enzyme is highly specific for D- or L-alanine because it does not catalyze the racemization of other amino acids. In addition, after gel filtration, the enzyme did not require exogenous pyridoxal 5'-phosphate (PLP) for its activity, however, the effects of several chemicals suggest that the enzyme may be PLP-dependent. The enzyme is more similar to that found in invertebrates when compared with that found in bacteria. This is the first report on the occurrence of alanine racemase activity in the microalga Thalassiosira sp.  相似文献   

Effects of reactive radicals and heat on <Emphasis Type="Italic">trans</Emphasis>-isomerization of eicosapentaenoic acid     

Nobuhiro Zaima  Tatsuya Sugawara  Yuki Otsubo  Takashi Hirata 《Fisheries Science》2007,73(4):897-901

Trans geometric isomers of eicosapentaenoic acid (TEPA) have been found as minor components in human platelets. However, there is little information on the mechanism of trans-isomerization of eicosapentaenoic acid (EPA) in vitro and in vivo. The effects of reactive radicals and heat on trans-isomerization of EPA were examined. Trans-isomerization occurred when EPA ethyl ester reacted with nitrogen dioxide radical (NO₂) but not with 2,2′-azobis(2,4-dimethylvaleronitrile). TEPA was also produced from EPA ethyl ester heated at 200°C for 60 h. No TEPA, however, was detected in sardines Sardinops melanostictus after boiling, roasting, or microwave heating. These results suggest that EPA is trans-isomerized by NO₂ in vivo while trans-isomerization of EPA does not occur during conventional cooking.  相似文献   

Inhibition activity of essential oils obtained from Japanese trees against <Emphasis Type="Italic">Skeletonema costatum</Emphasis>     

Kazuya Tsuruta  Yayoi Yoshida  Norihisa Kusumoto  Nobuhiro Sekine  Tatsuya Ashitani  Koetsu Takahashi 《Journal of Wood Science》2011,57(6):520-525

The growth inhibition activities of essential oils obtained from Cryptomeria japonica, Chamaecyparis obtusa, and Pinus thunbergii were examined against the bacillariophyceae Skeletonema costatum, also known as red tide plankton. The essential oils were extracted from the heartwood, leaves, and bark of these typical indigenous Japanese conifers. The essential oils from C. japonica bark and P. thunbergii heartwood possessed strong growth inhibition activity. The chemical compositions of these essential oils were analyzed by gas chromatography/flame ionization detection (GC-FID) and gas chromatography/mass spectrometry (GC-MS). α-Terpineol and longifolene were the main components of the essential oil from P. thunbergii heartwood. The C. japonica bark essential oil was mainly composed of α-terpineol, δ-cadinene, isophyllocladene, and ferruginol. Ferruginol and longifolene showed more potent growth inhibition against S. costatum than hinokitiol (β-thujaplicine), which is known to be a strong antifungal compound among wood components. Ferruginol and longifolene were important factors for the growth inhibition activity of the essential oils from C. japonica bark and P. thunbergii heartwood, respectively. These results suggest the possibility of using C. japonica bark and P. thunbergii heartwood for the control of red tide plankton.  相似文献   

Relationship between adipose maturity and fatty acid composition in various adipose tissues of Japanese Black,Holstein and Crossbred (F1) steers     

Ju‐Hwan LEE  Ichiro YAMAMOTO  Jin‐Suk JEONG  Toshihiro NADE  Toshiro ARAI  Nobuhiro KIMURA 《Animal Science Journal》2011,82(5):689-697

The amount of monounsaturated fatty acid (MUFA) is intimately related to adipose softness, melting point (MP) and flavor in beef. Stearoyl‐CoA desaturase (SCD) is a main gene involved in MUFA synthesis. Mature adipose tends to be highly saturated, whereas immature or maturing adipose is highly unsaturated when chronologically based, so the degree of non‐saturation can be an index of adipose maturity. In this study, three different adipose tissues (coelomic (CL), perirenal (PR), and subcutaneous (SC)) from three beef breeds with differing slaughter ages (Japanese Black (29.5 months), Holstein (20.1 month), and F1 crossbreed (25.6 months)) were examined to: (i) determine adipose maturity level as indexed by MUFA %; and (ii) determine SCD and other lipogenic gene messenger RNA (mRNA) expression levels in relation to unsaturated fatty acid content. Fatty acid composition was significantly different between adipose tissues (P < 0.05). MUFA amount was high in the following order: SC > CL > PR. This pattern corresponded to SCD mRNA expression profile showing higher expression in SC than CL and PR. However, Japanese black cattle are an exception with CL adipose containing similar UFA % as SC adipose, yet having the lowest SCD mRNA expression level among all adipose tissues tested. Therefore, SCD mRNA expression and MUFA % appear to be directly related; however, differences in SCD mRNA expression among three adipose tissues may reflect differences in the fat development characteristics affected by chronological age of the cattle breeds.  相似文献   

Therapeutic effect of anti-TNF-α antibody and levofloxacin (LVFX) in a mouse model of enterohemorrhagic Escherichia coli O157 infection     

Emiko Isogai  Hiroshi Isogai  Kimiharu Hirose  Toru Kubota  Koichi Kimura  Nobuhiro Fujii  Shunji Hayashi  Koichi Takeshi  Keiji Oguma 《Comparative immunology, microbiology and infectious diseases》2001,24(4)

The ability of an anti-TNF-α antibody to confer protection against enterohaemorrhagic Escherichia coli (EHEC) O157 was investigated in germfree IQI mice. The use of an antibiotic levofloxacin (LVFX) alone or with the antibody was also studied. Protection included an increase in survival rate. Treatment with the anti-TNF-α antibody inhibited the histological signs associated with EHEC infection but did not prevent the colonization of EHEC or production of Shiga toxin (Stx). No clinical signs were observed and EHEC was completely eliminated in the mouse model receiving both anti-TNF-α antibody and LVFX. Anti-TNF-α antibody suppressed inflammatory cytokine response in the mouse kidney and brain by EHEC infection.  相似文献   

Neuropathogenicity of mutant strains of mouse hepatitis virus, JHM   总被引：1，自引：0，他引：1  

N Goto  Y Tsutsumi  A Sato  K Fujiwara 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1987,49(5):779-786

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Comparative study of the effects of various cryoprotectants in preserving the morphology of frozen and thawed fowl spermatozoa     

T. Maeda  T. Terada  Y. Tsutsumi 《British poultry science》1984,25(4):547-553

1. The effects of various cryoprotectants (glycerol, dimethyl‐sulphoxide (DMSO), methylformamide and ethylene glycol) of the same molarity on preserving the morphology of frozen and thawed fowl spermatozoa (especially midpiece and acrosome) were examined under the light (LM) and scanning electron microscope (SEM) to determine the most suitable.

2. Under LM, the mean respective increases in sperm deformity in semen diluted with ethylene glycol, methylformamide, glycerol and DMSO were 4·5, 4·9, 5·0 and 6·5 percentage points.

3. Under SEM, the mean respective increases in acrosomal deterioration in semen diluted with glycerol, ethylene glycol, DMSO and methylformamide were 6·6, 8·8, 13·1 and 31·2 percentage points.

4. From these results, it appears that glycerol is superior to ethylene glycol DMSO and methylformamide as a cryoprotectant.

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Severe hypoplasia of the omasal laminae in a Japanese Black steer with chronic bloat--a case report     

Takagi M  Mukai S  Fushimi Y  Matsushita K  Miyoshi N  Yasuda N  Kitajima H  Takamure S  Matsushita T  Kitamura N  Deguchi E 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(12):1281-1286

An 11-month-old Japanese Black steer with chronic bloat underwent clinical and histological analyses. During the observation period, it showed normal appetite and fecal volume but persistent chronic bloat symptoms. Compared to controls, the steer's feces contained undigested large straws. Necropsy revealed normal rumen, reticulum, and abomasum but a small omasum. The rumen, reticulum, and abomasum mucosa was normal, with well-developed ruminal papillae. However, severe hypoplasia of the omasal laminae was observed along with hypoplasia reticular groove and ruminoreticular fold. The contents of the reticulum, omasum, and abomasums comprised undigested large sized hay particles. The omasum papillae showed no pathological abnormalities. This is a rare case of a steer with chronic bloat probably caused by severe hypoplasia of the omasal laminae.  相似文献   

Timing of Puberty and Its Relationship with Body Growth and Season in Male Raccoons (Procyon lotor) in Hokkaido     

Minami W. OKUYAMA  Michito SHIMOZURU  Go ABE  Mariko NAKAI  Mariko SASHIKA  Ken-Ichiro SHIMADA  Nobuhiro TAKAHASHI  Daisuke FUKUI  Ryohei NAKAMURA  Toshio TSUBOTA 《The Journal of reproduction and development》2013,59(4):361-367

The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.  相似文献