Glycolipids Isolated from Spirulina maxima: Structure and Fatty Acid Composition

Several glycolipids were isolated from Spirulina maxima, an edible blue-green algae, by systematic fractionation with different solvents. Structural investigation by using methylation, GC-MS, and enzymic techniques indicated that the major glycolipids are O-β-d-galactosyl-(1→l′)-2′, 3′-di-O-acyl-d-glycerol, O-α-d-galactosyl-(l-→6)-O-β-d-galactosyl-(1→l′)-2′,3′-di-O-acyl-d-glycerol and 6-sulfo-O-α-quinovosyl-(l→l′)-2′, 3′-di-O-acyl-d-glycerol. Main fatty acid components of these glycolipids were identified as palmitic acid and linoleic or linolenic acid. Based on-these fatty acid compositions, Spirulina glycolipids were compared with those in higher plants.     

Isolation of R-(−)-3-Hydroxy-β-ionone from Burley Tobacco

The tritium-hydrogen exchange method was used to determine the total racemization of amino acid residues of four proteins (ribonuclease A, lysozyme, soybean protein and casein) during their exposure to an alkali. Tritium was incorporated with first order kinetics into these proteins during their incubation in 0.2 n NaOH at 40°C. The tritium-hydrogen exchange increased as the temperature and the alkali concentration increased. In contrast, pepsin digestibility decreased extensively in the initial stage of the treatment. This phenomenon was verified by the subsite theory of protease, that only minor racemization renders the extended range of the peptide chain around the racemized amino acids non-susceptible to pepsin. General precautions against the racemization of food protein treated with alkalis are discussed briefly in terms of the deterioration of nutrients.     

Characterization and Functional Properties of Sub-Fractions of Soluble Soybean Polysaccharides

Soluble soybean polysaccharide (SSPS) was fractionated into two sub-fractions, a high-molecular-weight fraction (HMF) and a low-molecular-weight fraction (LMF) by the ethanol-extraction method. Characterization of the sub-fractions, that is, analysis of chemical composition, gel filtration, and SDS–PAGE, revealed that the main component of HMF was a large polysaccharide molecule with covalently-attached peptides, possibly corresponding to the intact SSPS molecule. LMF consisted of free peptides and saccharides of small size, which might have occurred as by-products during the production process of SSPS. HMF exhibited high ability to emulsify oil droplets and stabilize α-casein dispersions in an acidic pH region, but this ability of LMF was inferior to HMF. On the other hand, LMF had higher activity to prevent the oxidation of emulsified lipids than HMF. These results suggest that HMF and LMF had different characteristics and functional properties, and that the combination of the two sub-fractions generates the multi-functions of commercial SSPS.     

Microencapsulation of Linoleic Acid with Low- and High-molecular-weight Components of Soluble Soybean Polysaccharide and Its Oxidation Process

Soluble soybean polysaccharide (SSPS) was fractionated into its low- (LMW) and high-molecular-weight (HMW) components to test their antioxidative and emulsifying properties. Linoleic acid was emulsified with an aqueous solution of SSPS, HMW, a mixture of LMW or HMW with maltodextrin, or maltodextrin alone. The emulsions prepared with SSPS, HWM and the mixture of HMW with maltodextrin were stable. These emulsions were spay-dried to produce microcapsules. The encapsulated linoleic acid was oxidized at 37°C and at various levels of relative humidity. Linoleic acid encapsulated with the mixture of LMW with maltodextrin or HMW was stable to oxidation, and this stability increased as the weight fraction of LMW in the mixture was increased. The LMW components also had high DPPH-radical scavenging activity. These results indicate that LMW played an important role in suppressing or retarding the oxidation of linoleic acid encapsulated with SSPS. The oxidative stability of linoleic acid encapsulated with a mixture of the LMW and HMW components was high at low and high relative humidity, but not at intermediate levels of relative humidity.     

虫草多糖的分离、纯化和初步药效活性研究

以虫草发酵菌丝体为原料提取虫草多糖并对多糖进行结构鉴定和初步药效活性研究。采用水提醇沉和离子交换纤维素进行分离得到两种虫草多糖,HPLC测定相对分子质量,紫外光谱、红外光谱、部分酸水解、甲基化分析和高效液相色谱等方法研究单糖组成及连接方式,四甲基偶氮唑盐微量酶反应比色法（MTT）检测虫草多糖的活性。经分离得到中性（CPSl）、酸性（CPS2）两种成分,相对分子质量分别为2．56×10^4,9．91×10^;单糖组成：CPSln,（葡萄糖）：n（甘露糖）：n（半乳糖）：n（阿拉伯糖）=46：36：18：l;CPS2／n,（葡萄糖）：n,（甘露糖）：n（半乳糖）：n（半乳糖酸）：n（木糖）：n（阿拉伯糖）：n（鼠李糖）=30：25：14：4：3：3：1。红外谱揭示均含-a-键。CPSl主链含（1→6）糖苷键的高度分支的葡甘露半乳聚糖,另有少量葡萄糖分支点在2,3,4位。CPS2主链含葡萄糖（Glc）、甘露糖（Man）、半乳糖（Gal）,分支点主要在3位,侧链含多种单糖。CPSl和CPS2都对顺铂（CDDP）损伤的vero细胞有一定保护作用。     

3种进化类型大豆叶片的某些生理特性比较

半野生、半栽培和栽培大豆叶片可溶性糖和可溶性蛋白含量以及过氧化物酶（POD）和超氧化物歧化酶（SOD）活性均表现为随品种的进化而增加的变化趋势。POD活性在生育期中呈上升变化,SOD活性则随着生育进程逐渐下降。栽培大豆的可溶性糖含量和POD活性以上部叶片最高,半栽培大豆与栽培大豆类似,半野生大豆的变化则不明显。     

Effects of Lecithin Addition in Oil or Water Phase on the Stability of Emulsions Made with Whey Proteins

The effects of lecithin addition in oil or water phase on the stability of oil-in-water emulsions made with 0.1 wt% whey protein and 10 wt% n-tetradecane at neutral and acidic pH were studied by monitoring the gravitational creaming and phase separation. The effects of lecithin addition on the interfacial behavior of β-lactoglobulin were also studied to compare with the results of emulsion stability. At neutral pH, crude phosphatidylcholine (PC) from egg yolk or soybean increased the stability of the emulsion made with protein and lowered the interfacial tension of protein films more effectively than pure egg PC. A more remarkable effect on both the emulsion stability and the interfacial tension was found when crude PC was added in the oil phase rather than in the water phase. The purity of lecithins and the way to add them are suggested to be very important to make a stable emulsion with protein. On acidic pH (4.5 or 3.0), the increased creaming or phase separation in a whey protein-stabilized emulsion, but the lowered interfacial tension of β-lactoglobulin films, were found upon the addition of pure or crude PC in oil or water phase. These results suggest that in acidic pH, densely packed films may be formed on a planar oil–water interface, but not on adsorbed layers around oil droplets in an emulsion.     

天麻生长过程中可溶性蛋白和多糖的累积规律

以不同来源的蜜环菌 [(Armillariamellea(Vahl.exFr.)Qu啨ｌ.) ]4个菌株分别伴栽红天麻 (GastrodiaelataBl.f.elata)、乌天麻 (GastrodiaelataBl.f.glaucaS .Chow)以及红乌杂交天麻 ,对天麻生长发育过程中可溶性蛋白和多糖含量的变化规律进行了初步研究。结果表明 ,随着天麻的生长 ,菌株M1 、M2 、M3和M4 伴栽的红天麻、乌天麻以及红乌杂交天麻中 ,其可溶性蛋白含量均在逐步增加 ;在同一生长期内 ,4个菌株伴栽的红乌杂交天麻中可溶性蛋白含量大于红天麻和乌天麻。由菌株M1 、M2 、M3和M4 伴栽的红天麻、乌天麻以及红乌杂交天麻 ,其多糖含量呈现先升高后下降的趋势 ;在同一生长期中 ,4个菌株伴栽的红天麻的多糖含量大于乌天麻和红乌杂交天麻。     

车前草粗多糖提取及抗氧化试验

采取热水浸提-醇沉法探讨了车前草中可溶性粗多糖的提取工艺,研究了提取温度、提取时间、提取次数与料液比4因素对多糖提取的影响。单因素试验发现,在80℃,120 min,料液比1:20,提取2次条件下多糖提取较好。正交试验优化提取方案为90 min、80℃和料液比1:25,在此条件下,多糖提取率可以达到29.88 mg.g-1。同时还研究了体外条件下对.OH和O2-.自由基的清除效果。研究发现,多糖与.OH自由基清除呈良好的线性量效关系(y=5.48x+31.34,r=0.9823),与O2-.清除也呈现良好的线性量效关系(y=4.334x+34.134,r=0.9979)。IC.OH-50%为114.57 mg.L-1,ICO2--50%为172.85 mg.L-1,试验结果充分表明车前草多糖在体外有较强的自由基清除能力。     

Production of l-Lysine by Leucine Auxotrophs Derived from AEC Resistant Mutant of Brevibacterium lactofermentum

The effect of amino acids was examined on the production of l-lysine by AEC resistant mutant of B. lactofermentum. Among amino acids tested, only leucine showed strong specific inhibition. In order to release the production of l-lysine from this negative effect of leucine, leucine auxotrophs were derived from AEC resistant strain of B. lactofermentum. Most of these leucine auxotrophs produced larger amount of l-lysine (maximally 41 mg/ml) than the parental strain which produced about 18 mg/ml of l-lysine. It was confirmed that leucine auxotrophs derived from AEC resistant mutant of other glutamate producing bacteria, B. saccharolyticum and Corynebacterium glutamicum. These results suggested that leucine might directly or indirectly affect the biosynthesis of lysine.

However, this increase in lysine productivity of leucine auxotrophs could not be explained by the alteration of aspartokinase (EC 2.7.2.4) and homoserine dehydrogenase (EC 1.1.1.3). These enzymes are key enzymes in lysine and threonine biosynthesis, respectively.     

Synthesis of Some Di- and Tridepsipeptides Containing Hydroxy-methylbutyric Acid Involved in the Structure of a Depsipeptide Isolated from the Mushroom Sarcodon scabrosus

Some di- and tridepsipeptides containing hydroxymethylbutyric acid were synthesized. A comparison of their NMR spectra with those of the degradation products from the Sarcodon scarbrosus depsipeptide enabled assigning the natural compound preferentially to be cyclo-Hmb-Ile-Hmb-Ala-Thr-. The configuration of the residue of Hmb-Ile is postulated to be L-L, although it could possibly be D–D.     

Import Pathway of Nuclear-Encoded Cytochrome c Oxidase Subunit 2 Using Yeast as a Model

Abstract: Subunit 2 of cytochrome c oxidase (Cox2) is a mitochondrial-encoded protein in most organisms. In soybean Glycine max a second Cox2 gene was identified in the nucleus which is functional, whereas the mitochondrial-encoded cox2 gene is silent. For import and sorting of the nuclear-encoded soybean Cox2 protein ( Gm Cox2p) into mitochondria, the protein has acquired an N-terminal extension of 136 amino acid residues that is cleaved off in three steps during import. To study the function and processing of the Gm Cox2p leader peptide, we used yeast as a model system. Using different leader peptide-GFP constructs, we were able to show that the i₁ intermediate is generated in the mitochondrial matrix and the mature protein is generated in the inner membrane space. Mitochondrial processing peptidase (MPP) is involved in processing the first part of the leader peptide, processing of the last part is catalysed by the inner membrane peptidase (IMP). Oxa1p is necessary for insertion of the protein into the inner mitochondrial membrane. Gm Cox2p therefore utilises many of the same components as its mitochondrial-encoded predecessor, for sorting and maturation, following its import into the mitochondria.     

Purification,Characterization, and Crystallization of Single Molecular Species of β-Conglycinin from Soybean Seeds

Four major molecular species of β-conglycinin, α₃, α_2β, αβ₂, and β₃, were isolated and purified from seeds of an α' subunit-deficient strain of soybeans (Glycine max). All components were found to be homogeneous by high pressure liquid chromatography, SDS-polyacrylamide gel electrophoresis, and amino acid and amino terminal sequence analyses. The amino acid compositions of the α₃ and β₃ components agreed fairly well with the compositions deduced from the cDNA sequences, and all of the components were highly glycosylated. The α₃ and β₃ components were compared regarding their secondary structures. The secondary structure of the α₃ component deduced from CD measurements showed a higher α-helix content than that of the β₃ component. The β₃ component was crystallized by decreasing the ionic strength from 0.5 to 0.14 in phosphate buffer, pH 7.3, and the crystals grew to a size (1.0 mm × 0.2 mm × 0.2 mm) suitable for X-ray crystallographic analysis. A preliminary X-ray analysis showed that the crystal belonged to an orthorhombic crystal system having the space group P2₁2₁2₁ and unit cell dimensions of a = 185.1 Å, b = 107.9 Å, and c = 97.6 Å.     

体外模拟鳞杯伞子实体碱溶性多糖的消化与酵解特性

以热水浸提后的鳞杯伞Clitocybe squamulosa子实体残渣为原料,进行二次利用,浸提碱溶性多糖.通过模拟体外消化与厌氧发酵实验,探究鳞杯伞子实体碱溶性多糖的消化特性以及对肠道内短链脂肪酸含量的影响.结果 表明:体外模拟唾液和胃肠液消化后,多糖的官能团结构特征没有发生显著性改变,但碱溶性多糖的块状结构解体,碎...     

Binding forces between a novel Schiff base palladium(II) complex and two carrier proteins: human serum albumi and β-lactoglobulin

Ligand binding studies on carrier proteins are crucial in determining the pharmacological properties of drug candidates. Here, a new palladium(II) complex was synthesized and characterized. The in vitro binding studies of this complex with two carrier proteins, human serum albumin (HSA), and β-lactoglobulin (βLG) were investigated by employing biophysical techniques as well as computational modeling. The experimental results showed that the Pd(II) complex interacted with two carrier proteins with moderate binding affinity (K_b ≈ .5 × 10⁴ M^?1 for HSA and .2 × 10³ M^?1 for βLG). Binding of Pd(II) complex to HSA and βLG caused strong fluorescence quenching of both proteins through static quenching mechanism. In two studied systems hydrogen bonds and van der Waals forces were the major stabilizing forces in the drug-protein complex formation. UV–Visible and FT-IR measurements indicated that the binding of above complex to HSA and βLG may induce conformational and micro-environmental changes of two proteins. Protein–ligand docking analysis confirmed that the Pd(II) complex binds to residues located in the subdomain IIA of HSA and site A of βLG. All these experimental and computational results suggest that βLG and HSA might act as carrier protein for Pd(II) complex to deliver it to the target molecules.     

Coordination between Bradyrhizobium and Pseudomonas alleviates salt stress in soybean through altering root system architecture

It is a well accepted strategy to improve plant salt tolerance through inoculation with beneficial microorganisms. However, its underlying mechanisms still remain unclear. In the present study, hydroponic experiments were conducted to evaluate the effects of Bradyrhizobium japonicum USDA 110 with salt-tolerant Pseudomonas putida TSAU1 on growth, protein content, nitrogen, and phosphorus uptake as well as root system architecture of soybean (Glycine max L.) under salt stress. The results indicated that the combined inoculation with USDA 110 and TSAU1 significantly improved plant growth, nitrogen and phosphorus contents, and contents of soluble leaf proteins under salt stress compared to the inoculation with the symbiont alone or compared to un-inoculated ones. The root architectural traits, like root length, surface area, project area, and root volume; as well as nodulation traits were also significantly increased by co-inoculation with USDA 110 and TSAU1. The plant-growth promoting rhizobacteria (PGPR) P. putida strain TSAU1 could improve the symbiotic interaction between the salt-stressed soybean and B. japonicum USDA 110. In conclusion, inoculation with B. japonicum and salt-tolerant P. putida synergistically improved soybean salt tolerance through altering root system architecture facilitating nitrogen and phosphorus acquisition, and nodule formation.     

Taurine deficiency in maned wolves (Chrysocyon brachyurus) maintained on two diets manufactured for prevention of cystine urolithiasis

This study assesses the long‐term effects of an experimental diet vs. a commercially available manufactured diet, intended to reduce clinical disease related to cystinuria, on the taurine status of captive maned wolves. For 13 weeks, two pairs of maned wolves were maintained on the commercially available maintenance diet, whereas two individually housed wolves were maintained on the experimental diet. All six wolves, at the beginning and at the end of the diet trial, had severely decreased plasma concentrations of taurine (as compared to the normal canine reference range of 60–120 nmol/ml) (National Research Council [2003] National Academies Press) with average taurine concentrations of 16 nmol/ml at the beginning of the study and 3 nmol/ml at the end of the study. There was no statistically significant difference in the taurine concentrations between animals on the maintenance vs. experimental diets. Both diets were supplemented subsequently with taurine at a concentration of 0.3%. All study animals were eventually switched to the taurine‐supplemented version of the commercially manufactured maintenance diet and subsequent samplings were carried out to monitor plasma taurine concentrations. A final sampling, carried out approximately 5 months after the initiation of taurine supplementation, showed an average taurine concentration within the target canine reference range (90.25 nmol/ml). There are numerous physiologic (e.g., possible unique metabolism and requirements for taurine in this species as compared to other canids) and dietary factors (e.g., effects of the types and concentrations of fiber and protein on nutrient availability, taurine metabolism, and enterohepatic circulation of taurine‐conjugated bile salts; impaired taurine synthesis secondary to low cysteine availability) that could be potential contributors to the development of taurine deficiency in the maned wolves in this study. Taurine supplementation should be considered in maned wolves maintained on diets intended for reduction of cystinuria‐related complications. Zoo Biol 0:1–14, 2005. © 2005 Wiley‐Liss, Inc.     

Soluble carbohydrate content of soybean [Glycine max (L.) merr.] somatic and zygotic embryos during development

Summary Somatic and zygotic embryos of soybean cv. Jack were analyzed for soluble carbohydrate, total lipids, and protein during development. Zygotic embryos accumulated trace amounts of fructose, galactose, and galactinol., whereas somatic embryos contained only trace amounts of galactose. Somatic embryos accumulated much higher glucose levels than zygotic embryos. Both somatic and zygotic embryos contain low levels of sucrose, myoinositol, and pinitol. Raffinose and stachyose accumulated in the late developmental stages of zygotic embryos, but only stachyose was found to accumulate in the late stage somatic embryos. Zygotic embryos contained low total lipid levels up to 50 d after flowering (DAF) and then the levels increased to 16% by 55 DAF and 21% at 65 DAF. Somatic embryos had low levels of total lipids throughout development with the maximum of only 4.7%. Soybean zygotic embryos contained about 40% protein throughout development, while the protein concentration of somatic embryos decreased from 44% to 25% as maturation approached. These studies demonstrate that the composition of Jack zygotic embryos is similar to that described for other cultivars during development while the somatic embryo composition and size is markedly different. The low somatic embryo germination often noted might be due to the abnormal development as shown by a composition different from that of mature zygotic embryos. The low concentration of the raffinose series sugars might be especially important factors.     

豆皮水溶性多糖组分SHP-3的物化性质研究(英文)

对豆皮采用热水浸提得到豆皮水溶性多糖,通过DEAE-cellulose离子交换柱洗脱,得到3个组分。本文主要研究了采用0.3 M NaOH溶液洗脱纯化得到的组分SHP-3的物化性质。对SHP-3进行凝胶渗透色谱、气相色谱分析、紫外光谱及高碘酸氧化-Smith降解分析,结果表明:SHP-3的分子量为45554,其糖醛酸含量为26.71%(wt.%),单糖组成摩尔比为Rah:Fuc:Ara:Xyl:Man:Gal:Glu=3.55:0.44:11.58:1:7.45:5.12:1.12,紫外光谱在260～280 nm没有吸收峰,表明没有蛋白质或核酸等物质;高碘酸氧化-Smith降解结果表明SHP-3的连接结构以为(1→4)糖苷键为主,其摩尔比例占68.9%,(1→2)糖苷键占11.4%,(1→6)糖苷键占19.7%。     

利用大豆乳清废水生产SCP的研究

以大豆乳清废水为原料,通过对产朊假丝酵母的培养,使大豆乳清废水中的营养成分被酵母菌吸收利用,从而使菌体生长繁殖产生单细胞蛋白。单细胞蛋白(SCP)产量为8.7 mg/mL,蛋白含量为51.3%;且废水COD去除率达到73.4%,达到了国家乳清废水的标准,从而实现了废水资源化利用的目的。