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941.
The effects of several factors related to lipids on bovine adipocyte differentiation were investigated in primary culture. Adipocyte differentiation was assessed by development of glycerol-3-phosphate dehydrogenase (GPDH) activity and morphological observation. Addition of triglyceride mixture (Intralipid), caprylic acid and very low-, low- and high-density lipoproteins (VLDL, LDL and HDL) stimulated bovine preadipocyte differentiation in serum-free condition. Especially, VLDL strongly increased both cell protein contents and GPDH activity, suggesting that it stimulated both proliferation and differentiation of bovine preadipocytes. Under Intralipid-induced condition, differentiation of preadipocytes from subcutaneous adipose tissues was more evident than those from omental adipose tissues. However, such depot difference was not observed in medium supplemented with indomethacin, which is a peroxisome proliferator-activated receptor (PPAR) gamma agonist. This suggests that the differentiation capacity of bovine preadipocytes was different between depots and such difference is dependent on the ability to utilize lipids as endogenous PPARgamma ligands. Therefore, lipid metabolites have the stimulatory effects on bovine adipocyte differentiation in vitro, and lipoproteins, especially VLDL, may play an important role in development of bovine adipose tissues in vivo.  相似文献   
942.
Progesterone (P4) and estradiol-17beta (E2) concentrations were measured in serum samples obtained from 23 captive and 23 free-ranging adult female Japanese black bears. We then determined the relationship between changes in these sex steroid hormones and pregnancy. In all captive bears, which included animals of both known and unknown reproductive status, serum P4 concentrations were low from April to July, then tended to become higher after August. The levels then became much higher still in November and December, but returned to low levels in March. Serum P4 concentrations in eight captive pregnant bears, which had parturitions the following spring, increased gradually from August (0.5-2.4 ng/ml) to October (0.9-3.6 ng/ml), and achieved significantly higher maximum levels in December (7.2-18.0 ng/ml). Thereafter, serum P4 concentrations tended to decrease (3.5-6.4 ng/ml in January and 0.3-0.7 ng/ml in March). In all captive bears, serum E2 concentrations varied from April to October but showed low levels in November and December, and became high in January. Serum E2 concentrations in the eight pregnant bears were high in May (95.6-191.4 pg/ml) and varied from August to October (35.6-143.3 pg/ml). Subsequently, serum E2 concentrations in December dropped to significantly lower minimum levels (5.3-11.9 pg/ml) and increased again in January (67.6-153.1 pg/ml). Among the free-ranging bears, the data on serum P4 concentrations in eight bears led to expectations of pregnancy, whereas serum E2 concentrations showed no distinct evidence related to pregnancy. These results, particularly in captive pregnant bears, indicate that a marked increase of P4 in December might be accompanied by reactivation of the corpus luteum preceding implantation. Furthermore, changes in E2 concentrations suggested the possibility that a decline in December and an increase in January are associated with implantation and parturition, respectively.  相似文献   
943.
Between 1991 and 1993, the intestinal contents and feces of wild animals in Japan were examined for the presence of Listeria. The wild animals examined included 623 mammals (11 species) and 996 birds (18 species). Listeria species were isolated from 38 (6.1%) of the 623 mammalian samples and 133 (13.4%) of 996 bird samples. The highest incidence of Listeria in the mammals was found in Japanese monkeys (20.0%) and that in birds was found in crows (43.2%). The incidence of Listeria in Japanese monkeys varied from 0 to 40.0% depending on the capture area. L. monocytogenes was isolated from II of these positive samples. Serovars 1/2a and 4b predominated in eight serotyped L. monocytogenes isolates.  相似文献   
944.
Xanthomonas oryzae pv. oryzae strain T7174R is lysed by bacteriophage OP1h and OP1h2. Three mutants tolerant to both OP1h and OP1h2 were isolated by transposon mutagenesis. The mutants had an insertion of the transposon in XOO1687, which is predicted to encode a TonB-dependent receptor gene. Plasmid pHMIroNB that contained XOO1687 of T7174R was constructed, and the mutant was transformed with the plasmid. The transformant recovered sensitivity to OP1h and OP1h2. Electron microscopic analysis demonstrated that OP1h and OP1h2 can adsorb to the wild type and the transformant, but they could not adsorb to the phage-tolerant mutant. These results suggest that the TonB-dependent receptor gene relates to adsorption and infection of T7174R by OP1h2 and OP1h. Y. Inoue and S. Tsuge have contributed equally to this work.  相似文献   
945.
Clover yellow vein virus (ClYVV) elicits lethal tip necrosis in the pea line PI 118501. Pea line PI 118501 develops necrotic lesions and veinal necrosis on inoculated leaves, followed by systemic necrosis, leading to plant death. To understand the genetic basis of this lethal tip necrosis, we crossed lines PI 226564 and PI 250438, which develop mosaic symptoms in response to ClYVV inoculation. In reciprocal crosses of PI 118501 with PI 226564, all F1 plants had mosaic symptoms with slight stem necrosis and early yellowing of upper leaves. Essentially the same symptom was manifested in PI 118501 × PI 250438 F1 plants. In F2 populations from the cross between PI 118501 and PI 226564, the observed ratios of necrosis, mosaic with slight stem necrosis, and mosaic fit the expected 1 : 2 : 1 ratio. These results indicate that a single incompletely dominant gene confers the induction of necrosis in PI 118501. This locus in pea, conferring necrosis induction to ClYVV infection, was designated Cyn1 (Clover yellow vein virus-induced necrosis). A linkage analysis using 100 recombinant inbred lines derived from a cross of PI 118501 and PI 226564 demonstrated that Cyn1 was located 7.5 cM from the SSR marker AD174 on linkage group III.  相似文献   
946.
The aim of the present study was to determine the mechanism of cytosolic calcium ion concentration [Ca2+]i elevation in chicken and rat phagocytes stimulated with phorbol myristate acetate (PMA), leukotriene B4 (LTB4), formyl‐methionyl‐leucyl‐phenylananine (fMLP) and Saccaromyces cerevisiae culture supernatant (SCS). Pretreatment with EGTA completely suppressed the PMA‐induced [Ca2+]i elevation in rat and chicken phagocytes, suggesting that all the [Ca2+]i elevation induced in the PMA‐stimulated rat and chicken phagocytes was attributable to the influx of extracellular Ca2+. On the other hand, the elevation of LTB4‐, FMLP‐ and SCS‐induced [Ca2+]i was only partially suppressed by ethyleneglycol‐bis (β‐aminoethyl)‐N,N,N′,N′‐tetraacetic acid ethylene (EGTA) pretreatment of phagocytes. The results indicated that two pathways of [Ca2+]i elevation, recruitment from the intracellular Ca2+ store and influx of extracellular Ca2+, are involved in the [Ca2+]i elevation of LTB4‐, fMLP‐ and SCS‐stimulated phagocytes. In fMLP‐stimulated rat neutrophils, [Ca2+]i elevation showed a two‐phase pattern in which the time lag between the first and second phase was approximately 1 min. The EGTA treatment of the fMLP‐stimulated cells induced a reduction of the first phase level and a disappearance of the second phase. The reason for the special influence of EGTA observed in fMLP‐stimulated cells is unknown, but the disappearance of the second phase of the [Ca2+]i may be elicited by the EGTA‐induced decrease of the first phase [Ca2+]i elevation that depends on IP3 and diacylglycerol induced by fMLP.  相似文献   
947.
Methionine imbalance and toxicity in calves   总被引:1,自引:0,他引:1  
The occurrence of methionine imbalance and toxicity was examined using 70- and 100-kg Holstein bull calves. The animals had been trained to maintain reflex closure of the reticular groove after weaning at 5 wk of age, and Trials 1 (n = 30) and 2 (n = 24) were conducted on animals at 7 and 12 wk of age, respectively. Calves received a corn-soybean meal diet in Trial 1 and a corn-corn gluten meal diet in Trial 2. In Trial 1, postruminal administration of 6 g of DL-methionine/d increased ADG, feed intake, gain/feed, and N retention compared with a control group receiving N-free supplement. However, the administration of 12 g of DL-methionine/d did not improve these variables, whereas both 18 and 24 g/d resulted in BW loss and decreased gain/feed and N utilization efficiency. In Trial 2, postruminal administration of 16 g/d of L-lysine from L-lysine monohydrochloride increased ADG, gain/feed, and N utilization efficiency compared with a control group receiving a N-free supplement. The administration of 8 g of DL-methionine/d in addition to L-lysine did not exert an adverse effect on these variables. However, the additional supplementation of 16 and 24 g of DLmethionine/d negated the improvement, whereas 32 g/d resulted in BW loss and decreased gain/feed and N utilization efficiency. These results showed that a methionine imbalance and toxicity occurred in calves with even a modest excess of DL-methionine, and 70-kg calves were more susceptible to methionine toxicity than 100-kg calves. Plasma concentrations of branched-chain amino acids and phenylalanine linearly decreased with increasing amounts of additional DL-methionine from 0 to 32 g/d in Trial 2. However, such a decrease occurred mainly within the range from 0 to 12 g/d in Trial 1. This decrease was suggested to occur in relation to methionine metabolism via the transsulfuration pathway.  相似文献   
948.
949.
Callose (1,3-beta-glucan) is a suggested physiological indicator of aluminum (Al) toxicity in crop plants. It is not known if callose serves a similar function in forest trees, because quantitative data on callose formation in tree roots are limited, particularly under controlled conditions. To evaluate callose as a physiological indicator of Al toxicity in tree roots, we quantified callose formation in roots of Norway spruce (Picea abies (L.) Karst.) seedlings. Seedlings were grown in simulated soil solutions in the presence or absence (control) of Al under controlled conditions. In seedlings grown in solutions containing 280 microM Al, callose concentrations in roots were twice as high as control values after 6 h of Al treatment and 5 times higher than control values after 1 day. Thereafter, root callose concentrations gradually decreased and were only twice as high as control values after 7 days. The presence of various Al concentrations in the simulated soil solutions indicated that callose was induced by a relatively low Al concentration (84 microM). We conclude that callose in tree roots is an indicator of Al toxicity.  相似文献   
950.
Rehabilitated forests established about 100 years ago on denuded lands in a hilly granitic area are widespread in the Kyoto–Osaka area, the second largest megalopolis in Japan. From 2001 to 2003, we monitored the annual nitrogen (N) budget of a rehabilitated forest watershed dominated by Quercus serrata and Ilex pedunculosa. The ion concentrations of bulk rain in the watershed were similar to those of other watersheds in Japan. The annual bulk rain input of N ranged from 5.1 to 6.3 kg N ha−1 year−1, and the N deposition from throughfall and stem-flow ranged from 7.5 to 8.2 kg N ha−1 year−1. Estimated annual outputs of N from the stream ranged from 3.3 to 10.6 kg N ha−1 year−1. These results indicate that the amount of N deposition in this area is less than that in urban Tokyo (>10 kg N ha−1 year−1), but the N output of the watershed is comparable with that of the Tokyo area. We discuss the characteristics of N dynamics in rehabilitated forests, focusing on the biogeochemical processes of this watershed.  相似文献   
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