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1.
E. F. Annison R. E. Brown R. A. Leng D. B. Lindsay C. E. West 《The Biochemical journal》1967,104(1):135-147
1. Rates of entry and oxidation of a range of metabolites have been measured in tracheostomized sheep (diet, 800g. of lucerne chaff and 100g. of maize/day) by combining isotope-dilution techniques with the continuous measurement of total respiratory gas exchange, and 14CO2 production during the intravenous or intraruminal infusion of 14C-labelled substrates. 2. Mean entry rates in fed and starved (24hr.) sheep respectively, expressed as mg./min./kg. body wt.0·75, were: glucose, 5·0 (range 4·8–5·1, 2 observations) and 3·8 (3·2–4·2, 4); acetate, 10·8 (9·1–13·5, 4) and 5·8 (1); d(−)-β-hydroxybutyrate, 1·4 (1) and 1·5 (0·8–2·4, 4); palmitate, oleate and stearate (starved sheep only) 1·0 (0·6–1·9, 7), 0·9 (0·2–1·6, 10) and 0·9 (0·5–1·1, 11) respectively. 3. Production rates of propionate and butyrate in continuously feeding sheep were 6·4 (4·7–8·3, 4) and 4·3 (3·4–6·1, 4) mg./min./kg.0·75 respectively, and in starved (24hr.) sheep were 2·5 (2·2–2·9, 2) and 1·0 (0·8–1·2, 2) mg./min./kg.0·75 respectively. 4. Calculated terminal values for the specific radioactivity of respiratory 14CO2 during measurements of entry rates and production rates were used to calculate the contributions of individual substrates to overall oxidative metabolism. Mean values for fed and starved sheep respectively were: glucose, 9·1 (8·6–9·6, 2) and 11·2 (5·9–15·1, 4)%; acetate, 31·6 (26·8–38·1, 4) and 22·1 (1)%; d(−)-β-hydroxybutyrate, 10·4 (1) and 4·8 (1·9–7·7, 4)%; propionate, 23·0 (13·8–29·9, 4) and 7·1 (6·8–7·4, 2)%; butyrate, 16·5 (13·7–20·5, 4) and 5·3 (5·2–5·3, 2)%; palmitate, oleate and stearate (starved sheep only), 4·7 (2·0–7·7, 7), 4·0 (1·2–6·6, 10) and 4·4 (3·8–5·8, 9)% respectively. The sum of these values for individual substrates in fed and starved sheep, excluding that of β-hydroxybutyrate and after correction of the glucose value for the known interrelations of this substrate with propionate, accounted for 76% and 58% respectively of total production of carbon dioxide. 5. Calculations based on the proportion of substrate entry directly oxidized indicated that the substrates studied accounted for 63% (fed sheep) and 43% (starved sheep) of total energy expenditure measured by oxygen uptake. The contribution of β-hydroxybutyrate was excluded, and corrections were made for glucose–propionate interrelations, and for the different rates of oxidation of the methyl and carboxyl fragments of acetate. 6. The present results have been combined with those obtained earlier in this Laboratory to examine the relationships between rates of substrate entry and oxidation, and concentrations of substrate in blood. Rates of entry of acetate, glucose, d(−)-β-hydroxybutyrate, palmitate and oleate (but not stearate) were well correlated with concentration in blood, and substrate contribution to production of carbon dioxide showed a similar correlation to blood concentration, except with glucose. 7. It was concluded that the general technique is of potential value in providing valid quantitative parameters of animal metabolism. 相似文献
2.
Methyl α- and β-pyranosides of D-galactose, D-glucose, and D-mannose have been oxidized with bromine in aqueous solution at various pH values. The resulting keto glycosides were converted into their more-stable O-methyloxime derivatives which were characterized by spectroscopy and chromatography. Oxidation at a ring carbon atom where the hydrogen is axial is hindered by bulky substituents in syn (i.e., a 1,3) diaxial relationship. Thus, the aglycon group in the α anomers protects position 3, the axial HO-4 in galactopyranosides protects position 2, and the axial HO-2 in mannopyranosides protects position 4 from oxidation. 相似文献
3.
S. Nowaczewski M. Babuszkiewicz T. Szablewski K. Stuper-Szablewska R. Cegielska-Radziejewska Ł. Tomczyk S. Kaczmarek A. Sechman M.W. Lis M. Kwaśniewska P. Racewicz Ł. Jarosz A. Ciszewski T. Nowak M. Hejdysz 《Animal : an international journal of animal bioscience》2022,16(7):100564
The transfer of hatchability results obtained under experimental conditions to the commercial ground with a positive financial effect proves the value and usefulness of these data. On the other hand, finding results on commercial processes of broiler breeders’ egg incubation in the literature is challenging. The presented study aimed to determine the effects of egg weight and storage time on the physical, biochemical characteristics of hatching eggs, embryogenesis and hatchability in Ross 308 broiler breeders. On the laying day, the eggs were divided into four weight groups: S – small eggs (57–61 g), M – medium eggs (62–66 g), L – large eggs (67–71 g), and XL – extra-large eggs (72–76 g). The eggs were then stored for 3, 7, 14, and 21 days under controlled conditions. As the egg storage time increased, a decrease in the yolk quality (lower index) was observed. The highest Haugh units were found in eggs from the S and M groups. The cholesterol content of the M, L, and XL groups was lower on days 7, 14, and 21 as compared to that of eggs only stored for 3 days. Egg weight loss during incubation decreased with an increase in the egg weight. An extension of the egg storage time caused an increase in the loss of egg weight. On the 14th and 18th days of hatching, an increase in the eggshell temperature was noted with an increase in the weight of the egg. The eggs stored for 7 days were characterised by the highest shell temperature on each day. The highest hatchability percentage was recorded for the M group. The hatchability rate decreased with the prolongation of the storage time, while the number of crippled chicks after hatching increased. The results confirmed that the increased weight of the eggs and prolonged storage time (14 and 21 days) increased the weight and decreased the length of the newly hatched chicks, respectively. Chicks from the heaviest eggs and those stored for 14 and 21 days showed poor results on the Pasgar score® test. The observations indicate the need to adopt various (of those available) methods to assess the quality of newly hatched chicks in hatcheries in order to produce high-quality broiler chickens. The results also indicate that prolonged egg storing beyond 14 days may affect the thyroid hormone economy during the hatching of chicks, especially in the XL group. 相似文献
4.
Claude-Yves Cuilleron Elisabeth Mappus Maguelone G. Forest Jean Bertrand 《Steroids》1981,38(6):607-632
The reduction of 3-ethylenedioxy-7-oximino-5-androsten-17β-yl acetate and of its 17β-tetrahydropyranyl ether analog with sodium in ethanol, followed by thin-layer chromatography, allowed the isolation of the corresponding 17β-hydroxy- and 17β-tetrahydropyranyioxy-5-en-7β- and 7α-amines which were also characte-rized as 7-acetamides. The acylation of the two epimeric 17β-hydroxy-5-en-7-amines with succinic anhydride followed by selective saponification of the 17β-hemisuccinate group and diazomethane esterification, gave the corresponding 17β-hydroxy-5-en-7β- and 7α-hemisuccinamido methyl esters characterized also as 17β-acetates. On the other hand, the acylation of the two 17β-tetrahydropyranyl-oxy-5-en-7-amines with the acid chloride of terephthalic acid monomethyi ester led to the more rigid 7β- and 7α-terephthalamido methyl ester side-chains. The acidolysis of the 3-ethyleneketal protecting group of the preceding 5-en-7-N-acyl derivatives regenerated the 4-en-3-oxo function while the 17β-tetrahydropyranyl ether group was cleaved simultaneously into the 17β-alcohol. The four desired 7β- and 7α-hemisuccinamido- and terephthalamido carboxylic side-chain derivatives of 17β-hydroxy-4-androsten-3-one (testosterone) were finally obtained by saponification of the corresponding methyl esters. 相似文献
5.
《Carbohydrate research》1985,138(1):1-15
Both diastereoisomers of 1-phenylethylidene acetals (acetophenone acetals) of methyl and benzyl β-l-arabinopyranoside and α-l-rhamnopyranoside were prepared. Acetal-exchange reactions gave only the endo-phenyl isomers; their 2-O- and 4-O-acetyl derivatives were isomerised into the exo-phenyl compounds. 1H-N.m.r. data were used to determine the absolute configuration at the acetal carbon atom in these compounds. The protons of the methyl group of the exo-phenyl isomers resonate at lower field than those of the endo-phenyl isomers. Hydrogenolysis of various methylene, ethylidene, and isopropylidene derivatives gave axial ethers. The endo-phenyl isomers of the acetophenone derivatives also gave axial 1-phenylethyl ethers in two diastereoisomeric forms. The exo-phenyl isomers of the arabinosides were stable towards the reagent (LiAlH4AlCl3), whereas the corresponding rhamnopyranosides gave the 2-(1-phenylethyl) ethers, but cleavage required prolonged reaction time and higher temperature. 相似文献
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Object recognition and classification by sensory pathways is rooted in spike trains provided by sensory neurons. Nervous systems had to evolve mechanisms to extract information about relevant object properties, and to separate these from spurious features. In this review, problems caused by spike train variability and counterstrategies are exemplified for the processing of acoustic signals in orthopteran insects. Due to size limitations of their nervous system we expect to find solutions that are stripped to the computational basics. A key feature of auditory systems is temporal resolution, which is likely limited by spike train variability. Basic strategies to reduce such variability are to integrate over time, or to average across several neurons. The first strategy is constrained by its possible interference with temporal resolution. Grasshoppers do not seem to explore temporal integration much, in spite of the repetitive structure of their songs, which invites for multiple looks at the signal. The benefits of averaging across neurons depend on uncorrelated responses, a factor that may be crucial for the performance and evolution of small nervous systems. In spite of spike train variability the temporal information necessary for the recognition of conspecifics is preserved to a remarkable degree in the auditory pathway.Abbreviations dB decibel - CV coefficient of variation - SNR signal to noise ratio 相似文献
8.
Fusarium, graminearum KF 370 isolate is able to simultaneous biosynthesis of three toxic metabolites, namely: fusarenone-X (FUS), nivalenol (NIV) and zearalenone (F-2). After metabolites extraction with methanol — water (3:1) and defatting with n-heptane toxins were partitioned into chloroform layer. Purification of the? compounds was performed on Celite 545 — charcoal — Aluminiumoxid 90 column then metabolites were separated on Kieselgel 60 (200–300 mesh) column with developing solvent chloroform — methanol. This way FUS, NIV and F-2 were obtained as crystalline or high purity standards. 相似文献
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Chemotactic properties of amino acids (L-alanine, glycine and L-lysine) and their oligopeptides (10–6M) and binding sites to these ligands were investigated in two unicellular models, the heterotrophicTetrahymena pyriformis and the auxotrophicDunaliella salina. Chemotaxis ofDunaliella induced by simple amino acids and their derivatives demonstrated that binding sites (receptors) for food molecules are not only present in the membrane but are also able to induce their basic physiological response. InTetrahymena, substances with special molecular structure and properties (polar, hydrophilic character of the signal peptide chain)-5-L-Lys, 5-Glywere required for chemoattraction, other peptides tested, lacking the required structure, were repellent. Divergences in chemotaxis and binding assays of both species suggest that trends of functional and binding parameters do not run parallel at this level of evolution. 相似文献
11.
Isolation, properties and spatial site analysis of γ subunits of B-phycoerythrin and R-phycoerythrin 总被引:2,自引:0,他引:2
Phycobiliproteins,whichincludephycoerythrin,phycocyanin,allophycocyaninandphycoerythrocyanin,arelightharvestingchromoproteinsinrhodophyceae,cyanobacteria,cryptophyceaeandsomepyrrophyceae[1,2].Phycobiliproteinsarecomposedofα,βandγ(onlyinphycoerythrin)subunit… 相似文献
12.
《Carbohydrate research》1987,168(1):55-65
Cora pavonia, a lichen having a basidiomycetous mycobiont, is rich in protein (36%), of which 10% is tyrosine. α,α-Trehalose is present and was isolated in 4.4% yield. The lichen was found to contain polysaccharides typical of basidiomycetes and different from those of ascomycetes and ascomycetous lichens. Isolated and characterized were a β-d-glucan and a heteropolysaccharide containing l-rhamnose, l-fucose, d-xylose, d-mannose, d-glucose, and d-galactose. The β-d-glucan was highly branched with 21% of nonreducing end-groups, contained 3-O-, 6-O-, and 3,6-di-O-substituted β-d-glucopyranosyl units, and had a main chain consisting of (1→3)- and (1→6)-links. The heteropolysaccharide component contained mainly mannose and xylose, having a mannose-containing nucleus and a main chain with preponderant (1→3)-linked α-d-mannopyranosyl residues. These were unsubstituted (10%), and 4-O- (10%) and 2,4-di-O-substituted (10%) with residues of β-d-xylopyranose. On methylation analysis of the heteropolysaccharide, a capillary column of DB-210 proved to be particularly useful for gas-liquid chromatographic resolution of partially O-methylated alditol acetates. 相似文献
13.
We have successfully cloned an α-galactosidase gene from a rice cDNA library and transformed it into Escherichia coli BL21. It was subsequently cloned to the pPIC9K vector and expressed in Pichia pastoris. A selected clone was found to result in high production yield of the galactosidase enzyme. The secreted enzyme was purified,
and it revealed as a major protein band on an SDS-PAGE gel. The optimal pH value, enzyme stabilities, and substrate specificity
were studied. The enzyme specificity toward the terminal α1→6, 1→4, and 1→3 linked galactosyl residue from various substrates
was investigated. By determining the Michelis constant (Km) of the enzyme for melibiose, raffinose, and stachyose, our results showed that melibiose was hydrolyzed faster than raffinose,
whereas the published data reported a reversed sequence, raffinose > melibiose. The enzyme also showed the ability of converting
B red blood cells into O red cells. The objective of this work is to develop the Pichia system to produce a large quantity of enzyme for blood cell conversion for transfusion. 相似文献
14.
Extracts of various flower tissues of tobacco with 70% methanol inhibited tobacco seed germination differently. Among them, extracts of stigma and anther were very inhibitory. When the extracts were partitioned between ethyl acetate and water, the activity of the ethyl acetate layer was stronger than that of the water layer. Stigmas and anthers had more abscisic acid (ABA) than the other floral tissues, which matched the results of the germination tests well. Guided by a bioassay using the inhibitory effects on tobacco seed germination, MeABA, ABA, and ABA-γ-d-glucopyranoside were isolated and identified from stigmas. All of the MeABA isolated did not seem to be an artefact produced by esterification with the solvent, for MeABA was detected even when stigmas were extracted with other solvents than methanol. MeABA and ABA did not inhibit tobacco pollen germination and elongation in vitro. 相似文献
15.
《Bioscience, biotechnology, and biochemistry》2013,77(4):1048-1055
α and β tubulin genes were cloned from the Capsicum annuum leaves using rapid amplification of cDNA ends (RACE)-PCR. Nucleotide sequence analysis revealed that 1,353 bp Capsicum annuum α?β-tubulin (CAnm α?β-TUB) encodes a protein of 450 amino acids (aa) each. The recombinant α?β tubulin was overexpressed mainly as an inclusion body in Escherichia coli BL21 (DE3), upon induction with 0.2 mM isopropyl-β-D-thiogalactopyranoside (IPTG), and its content was as high as 50% of the total protein content. Effective fusion protein purification and refolding are described. The average yields of α and β tubulin were 2.0 and 1.3 mg/l of culture respectively. The apparent molecular weight of each tubulin was estimated to be 55 kDa by SDS-polyacrylamide gel electrophoresis (PAGE). The tubulin monomers were found to be assembly competent using a standard dimerization assay, and also retained antigenicity with anti-His/T7 antibodies. The purified tubulins were polymerized to microtubule-like structures in the presence of 2 mM guanosine 5′-triphosphate (GTP). 相似文献
16.
R. Charoensapyanan Y. Takahashi S. Murakami K. Ito P. Rudeekulthamrong J. Kaulpiboon 《Applied Biochemistry and Microbiology》2017,53(4):410-420
The study was devoted to the synthesis of pentyl glucosides (PenGn) and isopentyl glucosides (Iso-PenGn) by transglycosylation using recombinant cyclodextrin glycosyltransferase from Bacillus circulans A11, β-cyclodextrin as a glucosyl donor and 1-pentanol and isopentanol as acceptors. TLC and MS analysis indicated at least 3 products which were in accordance with PenGn and IsoPenGn having glucose, maltose and maltotriose attached to the alkyl groups of both alcohols. Two products of each glucoside were purified by preparative TLC and their structures were identified by NMR technique to be pentyl-α-D-glucopyranoside (PenG1), pentyl-α-D-maltopyranoside (PenG2), isopentyl-α-D-glucopyranoside (IsoPenG1) and isopentyl- α-D-maltopyranoside (IsoPenG2). The effect of water-in-hexadecane emulsion on emulsion-forming properties showed that PenG2 had the highest emulsifying activity. Adding PenG2 to the insoluble Corynebacterium glutamicum amylomaltase from Escherichia coli transformants (A406R), helped to perform it to more soluble conformation. Moreover, it was found that PenG1,2 exhibited a higher antibacterial activity against E. coli ATCC 25922 than that of IsoPenG1,2. Hence, the biological properties of the synthesized products may be useful for their applications as emulsifying, solubilizing and antibacterial agents. 相似文献
17.
《Endocrine practice》2011,17(2):271-280
ObjectiveTo compare how the rapid-acting insulin analogues (RAIAs) aspart, lispro, and glulisine perform in continuous subcutaneous insulin infusion (CSII) therapy regarding (1) pharmacokinetic properties, (2) chemical and physical stability, and (3) pump compatibility.MethodsPubMed was searched for articles pertaining to the use of RAIAs in CSII, without a restriction on the time period.ResultsThese RAIAs have pharmacokinetic profiles that more closely mimic endogenous insulin in comparison with regular human insulin and tend to produce less hypoglycemia. Among these RAIAs, the rates of absorption and clinical efficacy in terms of glycemic control were similar. Although glulisine showed a faster onset of action in some studies with aspart and lispro, this advantage lasted only for a maximum of 1 hour, after which results were similar for glulisine and aspart or lispro. Each RAIA is created by making minor amino acid substitutions to the regular human insulin molecule and adding a stabilizer to help prevent fibrillation. A series of chemical and covalent changes affecting the primary structure of an insulin preparation, however, may cause decomposition during storage, handling, and use, diminishing the potency of the insulin molecule while contained in an insulin pump. Precipitation, fibrillation, and occlusion may ensue, undermining compatibility for CSII pump use. Aspart has demonstrated the greatest chemical and physical stability in the insulin pump, with the lowest rates of overall occlusion in comparison with lispro and glulisine (aspart 9.2%, lispro 15.7%, and glulisine 40.9%; P < .01).ConclusionAspart is the most compatible of the 3 RAIAs for pump use. (Endocr Pract. 2011;17:271-280) 相似文献
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Sperm‐associated and semen‐specific isoforms of α‐L ‐fucosidase are thought to function in fertilization in numerous organisms. Here, we report the localization, distribution, crypticity, and stability of this enzyme in mouse cauda epididymal sperm and cauda fluid. Western analysis revealed that the sperm‐associated α‐L ‐fucosidase is present as two isoforms (Mr ~49 and 56 kDa), whereas the cauda fluid α‐L ‐fucosidase shows a single band at 50 kDa. α‐L ‐Fucosidase activity was detected using the fluorogenic substrate 4‐MU‐FUC. Of the total α‐L ‐fucosidase activity recovered in the cauda epididymal contents, 74% was found in the cell‐free cauda fluid and about 7% was found in sperm cells. During capacitation or permeabilization, cryptic intracellular stores of soluble enzyme were released to the supernatant, while leaving bound enzyme concentrated within the small volume of sperm. Moreover, membrane‐associated enzyme activity was still detectable in acrosome‐reacted cells. Immunofluorescence studies support the presence of α‐L ‐fucosidase (originally localizing at the acrosomal area) at the equatorial segment after the acrosome reaction. α‐L ‐Fucosidase activity of both cauda fluid and sperm at 37°C, 5% CO2 was relatively stable and detectable up to 72 hr. The stability and appearance of mouse sperm‐associated α‐L ‐fucosidase in the equatorial segment after the acrosome reaction suggest that α‐L ‐fucosidase may be involved in sperm–egg interaction. Mol. Reprod. Dev. 79: 208–217, 2012. © 2011 Wiley Periodicals, Inc. 相似文献
20.
Systemically administered (–)nicotine (0.2–1.2 mg/kg, s.c.) significantly increased the release of acetylcholine (ACh), norepinephrine (NE) and dopamine (DA) in rat cortex. The lowest dose of (–)nicotine examined (0.2 mg/kg, s.c) also significantly elevated extracellular serotonin (5-HT) levels, and the maximal increases of extracellular ACh (122% at 90 min post injection) and DA levels (249% at 120 min post-injection) were observed following this dose. In contrast, the maximal increase of NE release (157% at 30 min post-injection) was observed following the highest dose of (–)nicotine injected (1.2 mg/kg, s.c.). This higher dose consistently produced generalized seizures. Repeating the (–)nicotine (0.58 mg/kg, s.c.) injection four hours after the first administration significantly elevated extracellular NE levels and also appeared to increase DA and CCh release. In addition, extracellular ACh and DA levels increased significantly in the dialysate after (–)nicotine was administered directly to the neocortex through the microdialysis probe membrane. Norepinephrine levels appeared to be elevated in the cortex following local administration as well. 相似文献