Influence of Body Weight and Food Density on Kinetics of Ammonia Excretion by the Brine Shrimp Artemia franciscana     

Yoshiaki  Tanaka 《Journal of the World Aquaculture Society》1993,24(4):499-503

This study was undertaken to quantify the relationships between the rate of ammonia excretion by brine shrimp and dry weight (body size) and food density. Measurements of the rate of ammonia excretion of the brine shrimp were made at 25 C in darkness. Under these conditions, the excretion rate of ammonium-nitrogen can be generalized as a function of body weight and food (Nannochloropsis sp.) density. The relationship between the body weight (W) and excretion rate of ammonium nitrogen (E_N) is expressed as E_N=α W^γ, where α is the metabolic level. The parameter α is dependent on ration, such that α=α_o±α_r where α_o= metabolic level in starvation and α_r= the metabolic level which increased with feeding or changed with the food density. In experiments in which the animal starved, the equation above becomes E_N=α_oW^γ, and the values of α and γ were 0.22 and 0.93, respectively. The rate of ammonium excretion rose from 5.42 × 10^?4 to 2.28 × 10^?1μg N/animal/h as dry weight measured from 1.57 × 10^?3? 1.04 mg dry weight per animal. Next, it is convenient to express α_r as α_r=α_fmax= (1 ? 10^?kc), where α_fmax is the maximum rate of α_f at saturated level of food density, C is the mean cell density, and k is a constant defining the rate of change of the metabolic rate with cell density. Therefore, the rate of ammonia excretion by brine shrimp could be expressed as E_N=α_o [1 ? a(l ? 10^?kC)]W^γ, and a =α_fmax/α_o. The values of the kinetics parameters obtained from experiments where shrimp were fed were a = 2.3 and k = 0.15×10^?7. Consequently, the maximum rate of ammonia excretion at a saturated food density is equivalent to 3.3 times the rate of animals that are not fed.  相似文献   

Protein synthesis measured in the whole body of chick embryos cultured in vitro     

K. Kita  S. Nakagawa  R. Pinontoan  J. Okumura  T. Muramatsu 《British poultry science》1993,34(5):1043-1047

1. Whole body protein synthesis was measured in chick embryos cultured in vitro. On day 7 of incubation chick embryos were cultured for 60 min in synthetic serum‐free medium containing 4‐[³H]phenylalanine. Specific radioactivities in free and protein‐bound phenylaline in the whole embryo were measured, starting 2 min after commencement of the culture process.

2. The values for fractional synthesis rate (FSR) estimated in vitro at 20, 30, 45 and 60 min during the embryo culture agreed well, ranging from 35 to 40%/d, suggesting that the method would serve as a useful model for studying the effect of growth promoters in chick embryos.

3. Bovine insulin in the synthetic medium did not affect FSR of protein in chick embryos cultured in vitro.  相似文献   

The rescue of Epstein--Barr virus from primary cultured cells of nasopharyngeal carcinoma.     

M Takada  M Murata  M Takei  S Nakagawa  H Okumura  A Kawamura 《Comparative immunology, microbiology and infectious diseases》1979,2(2-3):177-189

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Involvement of microaerophilic iron-oxidizing bacteria in the iron-oxidizing process at the surface layer of flooded paddy field soil     

Nakagawa  Koki  Murase  Jun  Asakawa  Susumu  Watanabe  Takeshi 《Journal of Soils and Sediments》2020,20(11):4034-4041

Journal of Soils and Sediments - To reveal whether microaerophilic Fe(II)-oxidizing bacteria (FeOB) participate in the Fe(II) oxidation at the oxic-anoxic interface in flooded paddy field soil,...  相似文献   

Influence of acute exposure to a low dose of systemic insecticide fipronil on locomotor activity and emotional behavior in adult male mice     

Mizuki MAEDA  Toshifumi YOKOYAMA  Sayaka KITAUCHI  Tetsushi HIRANO  Youhei MANTANI  Yoshiaki TABUCHI  Nobuhiko HOSHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(2):344

Fipronil (FPN) is a systemic insecticide that antagonizes the gamma-aminobutyric acid type A (GABA_A) receptors in insects. Recently, adverse effects of FPN on mammals have been reported, but most of those were caused by high doses of FPN and additives in the products. We investigated the effects of low-dose pure FPN on the emotional behavior of mice. Nine-week-old male mice conducted behavioral tests 24 hr after FPN administration by gavage at doses of 0.05 or 5 mg/kg based on the no-observed-effect level (NOEL), showed a significant increase in locomotor activity and dose-dependent responses on the time they spent in the central zone in the open field test. Pure FPN below the NOEL dose may affect the emotional behavior of mice.  相似文献   

Growth hormone suppresses the expression of IGFBP-5, and promotes the IGF-I-induced phosphorylation of Akt in bovine mammary epithelial cells     

Sakamoto K  Yano T  Kobayashi T  Hagino A  Aso H  Obara Y 《Domestic animal endocrinology》2007,32(4):260-272

Growth hormone (GH) plays a specific role to inhibit apoptosis in the bovine mammary gland through the insulin-like growth factor (IGF)-I system, however, the mechanism of GH action is poorly understood. In this study, we show that GH dramatically inhibits the expression of IGFBP-5, and GH along with IGF-I enhanced the phosphorylation of Akt through the reduction of IGF binding protein (IGFBP)-5. To determine how GH affects Akt through IGF-I in bovine mammary epithelial cells (BMECs), we examined the phosphorylation of Akt in GH treated BMECs and found that IGF-I induced phosphorylation of Akt was significantly enhanced by the treatment with GH. We demonstrated that GH reduces mRNA and protein expression of IGFBP-5 in BMECs, but it does not affect the expression of IGFBP-3. To determine that the enhanced effect of the Akt phosphorylation by the treatment of GH is due to the inhibition of the expression of IGFBP-5, we examined the effect of IGFBP-3 and -5 on the phosphorylation of Akt through IGF-I in the GH-treated BMECs. The phosphorylation of Akt was inhibited in a dose-dependent manner when IGFBP-5 was added at varying concentrations and was also inhibited in the presence of IGFBP-3. The results of this study suggest that GH plays an important role on mammary gland involution in bovine mammary epithelial cells.  相似文献   

Preventive effects of CIDR-based protocols on premature ovulation before timed-AI in Ovsynch in cycling beef cows     

Sakase M  Kawate N  Nakagawa C  Fukushima M  Noda M  Takeda K  Ueno S  Inaba T  Kida K  Tamada H  Sawada T 《Veterinary journal (London, England : 1997)》2007,173(3):691-693

Ovsynch is a program developed to synchronize ovulation for timed breeding. In this paper, the authors investigate whether controlled internal drug release (CIDR)-based protocols prevent premature ovulation before timed-artificial insemination (AI) when Ovsynch is started a few days before luteolysis in cycling beef cows. Nine beef cows at 16 days after oestrus were treated with (1) Ovsynch, i.e. gonadotropin releasing hormone (GnRH) analogue on day 0, prostaglandin (PG) F(2alpha) analogue on day 7 and GnRH analogue on day 9 with timed-AI on day 10, (n=3); (2) Ovsynch+CIDR (Ovsynch protocol plus a CIDR for 7 days from day 0, n=3), or (3) oestradiol benzoate (OB)+CIDR+GnRH (OB on day 0 in lieu of the first GnRH treatment, followed by the Ovsynch+CIDR protocol, n=3). In the Ovsynch group (1) plasma progesterone concentrations fell below 0.5 ng/mL earlier (day 5) than in both CIDR-treated groups (2) and (3), where this occurred on day 8. Plasma oestradiol-17beta concentrations peaked on day 8 in the Ovsynch group and on day 9 in both CIDR-treated groups. The dominant follicle ovulated on day 10 in the Ovsynch group and on day 11 in both CIDR-treated groups. Thus, both CIDR-based protocols prevented premature ovulation before timed-AI in Ovsynch when the protocol was started a few days before luteolysis. This reflects the fact that progesterone levels remained high until the beef cattle were treated with PGF(2alpha).  相似文献   

Differences in lectin-binding properties between the common mucosal epithelium and follicle-associated epithelium in the rabbit small intestine     

Takeuchi T  Fujibuchi T  Imai Y  Kamei Y  Murase R  Kito K  Abe Y  Ueda N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(6):645-647

Differences in sugar distribution between the villous epithelium and follicle-associated epithelium (FAE) were compared using lectins in the rabbit small intestine. In every portion, villous columnar epithelial cells primarily exhibited a positive reaction to the GalNAc, GlcNAc, galactose, and oligosaccharide. In the ileal Peyer's patch (PP), whereas microvillous epithelial cells exhibited positive reactions, M cells tended to be negative. The villous epithelial reaction to the fucose group was negative, but M cells and microvillous epithelial cells showed a positive to the fucose. No epithelium had a positive reaction to the mannose and glucose. The variety of lectin-binding properties of villous epithelial cells and M cells may reflect specificity for the recognizing luminal substances such as antigenic molecules and bacterial elements.  相似文献   

Quantitative structure-activity analysis of larvicidal 1-(substituted benzoyl)-2-benzoyl-1-tert-butylhydrazines against Chilo suppressalis     

Nobuhiro Oikawa  Yoshiaki Nakagawa  Keiichiro Nishimura  Tamio Ueno  Toshio Fujita 《Pest management science》1994,41(2):139-147

The larvicidal activity of a number of 1-(substituted benzoyl)-2-benzoyl–1 -ten-butylhydrazines against the rice stem borer (Chilo suppressalis Walk.) was measured. Variations in the activity were examined quantitatively using physico-chemical substituent and molecular parameters and regression analysis. The results indicated that the molecular hydrophobicity and the electron-withdrawing inductive/ field effect of ontho substituents are favourable to larvicidal activity. The bulkiness of substituents at the meta and para positions was unfavourable to activity, substitution at the para position being more unfavourable than that at the meta position in terms of van der Waals' volume. The 2,3–, 2,5- and 2,6-disubstitution patterns were also unfavourable to activity. Reductions in larvicidal activity caused by the 2,6-,- 2,3,5- and 2,3,4,5-substitutions were greater than those induced by the 2,3- and 2,5-disubstitutions. When the sum of contributions from favourable effects is greater than that from unfavourable effects, the larvicidal activity is expected to be superior to that of the unsubstituted compound.  相似文献   

Application of short-time magnetic resonance examination for intervertebral disc diseases in dogs     

Yamada K  Nakagawa M  Kato T  Shigeno S  Hirose T  Miyahara K  Sato M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(1):51-54

The usefulness of magnetic resonance (MR) is already established, but it has a disadvantage of requiring a long scanning time. A short-time examination is more or less needed so as to be more practical in veterinary clinics. A protocol of the short-time MR examination was devised based on parameters determined, and validity of the protocol was assessed through the diagnosis of clinical cases with intervertebral disc diseases. With this protocol, it was possible to complete an MR examination for the spine within 15 min. The MR images and myelographic findings were correlated well in this study, suggesting the short-time protocol of MR examination can be used in the clinical diagnosis of spinal diseases.  相似文献