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51.
The catabolism of arginine (Arg) by mixed rumen bacteria (B), mixed rumen protozoa (P), and their mixture (BP) was quantitatively investigated in an in vitro system in order to confirm the metabolic pathway of Arg and provide basic information for enzymatic and molecular studies as well as an understanding of the quantitative distribution of metabolites. Rumen microbial suspensions (B, P, and BP) collected from fistulated goats were anaerobically incubated with or without 1 mmol/L Arg at 39°C for 12 h. Arg and other related compounds such as citrulline (Cit), ornithine (Orn), proline (Pro) and 5‐aminovaleric acid (5AV) in both supernatant and hydrolyzates of B, P, and BP suspensions were analyzed by HPLC. The metabolic pathways of Arg in mixed rumen bacteria and mixed rumen protozoa were considered to be as follows: rumen bacteria, Arg → Cit → Orn → Pro → 5AV → VFAs + NH3; rumen protozoa, Arg → Cit → Orn → Pro → 5AV. The disappearance of Arg (1 mmol/L) was approximately 52.9 and 88.2% in B, 33.9 and 55.6% in P, and 52.8 and 85.2% in BP during 6 and 12 h incubations, respectively. When expressed in units of ‘per gram (g) of microbial nitrogen (MN)’, the net degradation rate of Arg in BP (50.3 µmol/g MN/h) was approximately 46% lower than that of B during a 12 h incubation period. The presence of protozoa tended to inhibit the production of Orn from Cit and the production of 5AV from Pro which were thought to be rate‐limiting steps of Arg metabolism in rumen microorganisms. As a result, protozoa appeared to have a saving effect on Arg metabolism, that is, protozoa protected Arg from wasteful exhaustion in the rumen.  相似文献   
52.
Knockdown and lethal activities of meta- and para-substituted benzyl (1R)-trans-chrysanthemates against the house fly were measured under synergistic conditions using piperonyl butoxide as an inhibitor of oxidative metabolism and NIA 16388 as an inhibitor of hydrolytic degradation. The variations in these activities were quantitatively analyzed in terms of physicochemical substituent effects using electronic, hydrophobic, and steric parameters of the aromatic substituents, and regression analysis. The most significant parameter in determining these activities is the steric bulkiness represented by the van der Waals voluem, the effect of which is highly specific to substituent positions. The substituent effects on knockdown and lethal activities against the house fly are shown to correspond well, respectively, with those on the convulsive and lethal activities against the American cockroach. The relationship between these symptomatic activities against the house fly and the neurophysiological activities determined by using excised nerve cords from American cockroaches were also quantitatively analyzed. Each house fly symptomatic activity was found to be analyzable by a linear combination of the neuroexcitatory and neuroblocking activity indices when the transport factor was separated by using the hydrophobicity parameter.  相似文献   
53.
We have previously shown that anacardic acid has an uncoupling effect on oxidative phosphorylation in rat liver mitochondria using succinate as a substrate (Toyomizu et al. 2000). In the present study, in order to clarify whether or not anacardic acid could be used advantageously as a special feed/food supplement to reduce fat deposition through the uncoupling action, two sets of experiments were conducted to determine quantitatively the effect of dietary anacardic acid (0.1% w/w) supplementation. More specifically, effects on growth, feed efficiency, fattening, and levels of several constituents of blood serum in rats fed normal and low protein–high carbohydrate (CHO) diets were examined. There were no significant differences in bodyweight gain, feed consumption and feed efficiency among the experimental groups. For the total fat pad content, including inguinal and epididymal fat, significant interaction was shown between both treatments: dietary anacardic acid at 0.1% w/w significantly decreased the total fat pad content in rats fed the CHO diet, but not in rats fed the normal diet. Weights of heart, spleen and brown adipose tissue were not affected by either the dietary treatment or anacardic acid, while both liver and kidney weights decreased with feeding of anacardic acid at 0.1% w/w, but were not affected by the CHO diet. Anacardic acid supplementation in the diet had no effect on serum glutamic oxaloacetic transaminase, alkaline phosphatase or lactate dehydrogenase levels, suggesting that the dysfunction of liver or kidney may not be induced by dietary anacardic acid. The results of the present study reveal a unique function of anacardic acid in that, for dietary conditions enhancing body fat deposition, that is consumption of a diet high in carbohydrates, dietary anacardic acid has the potential to decrease body fat deposition. A possible mechanism for differences observed in anacardic acid‐induced regulation of body fat pad content between rats fed the normal and CHO diets, based on uncoupling action of anacardic acid on the mitochondrial oxidative phosphorylation, is discussed.  相似文献   
54.
We evaluated the influence on milk production of feeding early lactation cows a diet that included 14.5% crude protein (CP) and that did not meet methionine (Met) requirements or that met them by supplying rumen‐protected Met (RPMet). Thirty‐nine multiparous Holstein cows were allocated into two groups. For 15 weeks after calving, each group was fed one of the two total mixed rations, Control (= 20) or Treatment (= 19). The Treatment group received added RPMet at 0.034% (8 g/day) of the Control diet on dry matter basis. The adequacies of Met for the Control and Treatment groups were 96% and 106%, respectively, and for other amino acids, >110%. The CP level (14.5%) was 1 percentage point lower than that recommended by the Japanese Feeding Standard (2006). No between‐group differences were found in milk yield (40 kg/day), milk composition, plasma profile, rumen fermentation, nitrogen balance, or cow health. Met intake and the amount of rumen‐undegradable feed Met were higher in the Treatment group (< 0.05). Microbial Met and total metabolizable Met did not differ between groups. Supplying RPMet in a 14.5% CP diet during early lactation did not dramatically affect milk production, because the amount of total metabolizable Met was unchanged.  相似文献   
55.
56.
The quantitative relationship between structure and inhibitory activity against the root growth of sawa millet of 30 N-aryl-3,4,5,6-tetrahydrophthalimides and 88 related N-aryl cyclic imide compounds (3-aryl-1,5-tetramethylenehydantoins, 4-aryl-1,2-tetramethylenetriazolidine-3,5-diones, and their thiocarbonyl analogs) was analyzed by means of physicochemical parameters of the aryl substituents and regression analysis. The results showed that, in each series of these classes of compounds, the position-specific steric effects of aromatic substituents, as represented by Verloop's STERIMOL values, are highly important in determining the inhibitory potency of the compound.  相似文献   
57.
Antifungal limonoids from the fruits of Khaya senegalensis   总被引:2,自引:0,他引:2  
Investigation of the fruits of Khaya senegalensis resulted in the isolation of three new mexicanolide limonoids containing a rare conjugated diene lactone system named seneganolide A (1), 2-hydroxyseneganolide A (2) and 2-acetoxyseneganolide A (3). Two known limonoids, 3-deacetyl-7-deacetoxy-7-oxokhivorin (4) and methyl 6-hydroxyangolensate (5), were also found. The structures of the new compounds were elucidated on the basis of spectral methods. The antifungal activity of compounds 1, 3 and 5 was tested against the fungus Botrytis cinerea.  相似文献   
58.
This article describes the catalytic effect of NaHCO3 on condensation reactions of monomeric hydroxymethylphenols (HMPs) to elucidate the cure-acceleration mechanism. By comparison of the kinetics of self-condensations of HMPs, NaHCO3 was proved to increase the reactivity of para-hydroxymethyl groups. The changes of 13C nuclear magnetic resonance (NMR) chemical shifts on each HMP system with the additive indicated that the addition of NaHCO3 enhanced some molecular interactions between HMPs and NaHCO3, facilitating a resonance effect that might play a similar role in dissociation of the phenolic hydroxyl groups of HMPs. In addition, computational modeling by molecular orbital calculations elucidated that hydrogen carbonate anion (HCO 3 ) forms an interaction between either the para-hydroxymethyl group and the phenolic hydroxyl group or between the two para-hydroxymethyl groups of HMPs by hydrogen bonds. From the experimental results, the authors proposed the mechanism of the catalytic action of NaHCO3: it appears to be due to the delocalization of an electron initiated by the interaction of the para-hydroxymethyl groups and the phenolic hydroxyl of HMPs with HCO 3 through hydrogen bonds, which results in facilitating the formation of active species.  相似文献   
59.
Flonicamid (IKI220; N-cyanomethyl-4-trifluoromethylnicotinamide), a pyridinecarboxamide compound, is a novel systemic insecticide with selective activity against hemipterous pests, such as aphids and whiteflies, and thysanopterous pests. The purpose of this study is to clarify the biological properties of flonicamid against aphids. Flonicamid is very active against aphids, regardless of differences in species, stages and morphs. This compound inhibited the feeding behaviour of aphids within 0.5 h of treatment without noticeable poisoning symptoms such as convulsion, and this antifeeding activity was not recoverable until death. The nymphs born from adults exposed to flonicamid for 3 h showed high mortality. The effect of flonicamid on the feeding activity of an individual aphid was studied using electronic monitoring of insect feeding behaviour (EMIF). Although the treated aphid attached the head of its proboscis to the leaf surface, salivation and sap feeding were strongly inhibited. These results suggest that the main insecticidal mechanism of flonicamid is starvation based on the inhibition of stylet penetration to plant tissues.  相似文献   
60.
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