应用超声波技术强化提取余甘多糖

通过单因素和正交实验研究了超声波时间、超声波功率、超声波提取温度和料液比对余甘(Phyllanthus emblica L.)多糖收率的影响。结果表明,多糖收率的主要影响因素为超声波功率、超声波时间、料液比、超声波提取温度。余甘多糖的最佳提取工艺条件为:超声波功率475W、超声波时间70min、料液比1:20、超声波提取温度80℃,余甘多糖收率为95.86mgg-1DW。紫外和红外光谱分析表明,余甘多糖是含有糖醛酸的α型吡喃酸性杂多糖,超声波处理没有改变多糖结构。     

紫菜多糖提取的研究

研究了热水浸提法提取紫菜多糖的最佳提取工艺,同时,对粗多糖进一步分离,并测定红外光谱图。实验表明：用热水浸提法提取的多糖产率在0．87％-2．55％之间,且多糖浸提液毫无凝固性。当料液比为1：30（g／mL）,温度为95℃,pH值为7,浸提时间为1．5h时提取的效果最好,得率可达2．546％。从紫菜粗多糖中可分离出两种多糖PP1和PP2,其中PP2的红外光谱图与标准琼脂糖样品相类似,而PP1的红外光谱图与PP2存在着较大的差异。     

微波法提取鼠尾藻多糖的工艺研究

研究采用了微波法提取鼠尾藻多糖,考查了微波辐照时间、微波功率、料液比、超声预处理时间四个因素的影响,并采用正交实验法确定微波提取的最佳工艺。结果表明微波法提取多糖产率为6.5%,其优化工艺条件为:微波辐照时间8 min,微波功率540 W,料液比1∶30,超声时间3 min。经红外光谱得知鼠尾藻多糖的主要组成单糖为吡喃糖。微波法提取鼠尾藻多糖可行,工艺简单,产率令人满意。     

正交实验法优选香菇多糖的提取工艺及其硫酸酯化研究

目的:考察香菇多糖的提取工艺,制备香菇多糖硫酸酯。方法:采用正交试验法考察加水量、提取时间、提取温度和粒度4个因素对香菇多糖硫酸酯提取率及其中总糖含量的影响,应用硫酸法制备香菇多糖硫酸酯并对得到的成分进行鉴别。结果:通过对正交实验结果的极差分析。得出提取温度和加水量对多糖提取率影响比较著性,提取温度和提取时间对多糖含量的影响比较著性。确定香菇多糖提取的最佳工艺为:应用40倍量的水,每次提取4 h,提取温度90℃,香菇粒度为80目。制备的多糖硫酸酯中硫酸基含量为22.80%,显示了相对较强的生物活性。结论:本实验成功的确定了提取香菇多糖的最佳工艺,制备了硫酸基含量较高的硫酸酯化香菇多糖。     

正交实验法优化极长钝顶螺旋藻多糖提取分离条件研究

目的:为研究螺旋藻最佳提取条件.方法:采用单因次试验和正交试验法考察提取时间、次数、温度和乙醇浓度对于多糖提取的影响.结果:确定了螺旋藻多糖的最佳提取工艺是温度80℃、时间3 h、提取次数2次和乙醇浓度为75%.结论:发现温度显著影响多糖提取率,而高浓度乙醇能提高得率.     

两种方法提取香菇多糖的比较研究

采用正交试验比较研究热水浸提法和微波提取法提取香菇多糖。热水浸提法的最佳工艺为:提取温度70℃、提取时间4h、料液比1∶15,提取率3.243%;微波提取法的最佳工艺为:微波功率560W、微波处理时间60s、料液比1∶10,提取率4.771%。微波提取法效率高、时间短,是理想的香菇多糖提取方法。     

Two Extraction Methods of Lentinan Polysaccharide

采用正交试验比较研究热水浸提法和微波提取法提取香菇多糖.热水浸提法的最佳工艺为:提取温度70℃、提取时间4h、料液比1∶15,提取率3.243 ％;微波提取法的最佳工艺为:微波功率560W、微波处理时间60 s、料液比1∶10,提取率4.771％.微波提取法效率高、时间短,是理想的香菇多糖提取方法.     

若羌红枣多糖提取方法的研究

目的:比较研究几种提取若羌红枣多糖的方法.方法:通过正交实验设计研究影响若羌红枣多糖提取的诸因素如提取料液比、温度、提取时间、提取次数等,确定条件范围,优化提取条件,得到提取若羌红枣多糖的最佳工艺条件.结果:热水法提取红枣糖的最佳条件:提取温度100℃、料液比1:16、提取时间4h,提取1次;酶法提取红枣多糖提取的最佳条件:pH4.5,温度60℃、时间1h,酶用世0.03%;碱法提取红枣多糖的对佳条件:Na2 CO3,温度80℃、时间3h,料液比1:20.结论:三种提取方法以酶提取法的效率最高,碱提取法次之,热水提取法的效率最低.     

槲蕨多糖的提取工艺优化及其抑菌性研究

以槲蕨块茎为材料,采用水提醇沉法提取槲蕨多糖.在单因素考察的基础上,以多糖的得率为响应值,料液比、提取温度、提取时间为自变量,建立数学模型,利用响应面法获得槲蕨多糖的最佳提取工艺.采用纸片扩散法比较了不同浓度多糖的抑菌效果.结果表明:槲蕨多糖最佳提取工艺条件为:料液比1:25,提取时间2.0h,提取温度为85℃,在此优化条件下多糖得率为7.57％,与响应面分析预测值7.61％基本相符.槲蕨多糖对杆菌有明显的抑制作用,对供试球菌无明显抑制效果,多糖最低抑菌浓度为10 mg/mL.     

苦楝果多糖的分离纯化及组成分析

利用水提醇沉法提取苦楝果实中的多糖,经DEAE-52柱层析分离,得到MP1、MP2和MP3三个多糖组分,用Sephadex G-100凝胶色谱柱对MP1进行纯化鉴定,结果显示为单一峰。借助气质联用仪,对苦楝粗多糖和组分MP1进行了成分分析。红外光谱分析表明苦楝多糖的单糖残基以吡喃环和呋喃环的形式存在。     

Tuning of electronic properties of one-dimensional cyano-bridged Cu-Ni, Cu-Pd, and Cu-Pt bimetallic assemblies by stereochemistry of ligands

Preparations, XPS and electronic spectroscopy, and magnetism of seven new one-dimensional cyano-bridged coordination polymers, chiral [Cu(RR-chxn)₂][Pd(CN)₄] · 2H₂O (1), [Cu(trans-chxn)₂][M(CN)₄] · 2H₂O (2, 4, and 6 for M = Pd, Ni, and Pt), and [Cu(cis-chxn)₂][M(CN)₄] · 2H₂O (3, 5, and 7 for M = Pd, Ni, and Pt) (RR-chxn = cyclohexane-(1R,2R)-diamine, trans-chxn = racemic trans-cyclohexane-(1,2)-diamine, and cis-chxn = racemic cis-cyclohexane-(1,2)-diamine) have been reported in view of tuning of their electronic properties by stereochemistry of chxn ligands and metal-substitution. Comparison of Cu 2p_1/2 and 2p_3/2 peaks of XPS and broad d-d bands around 18 000 cm⁻¹ of electronic spectra are described systematically for 1-7. Variable-temperature magnetic measurement shows that complexes 1-7 indicate weak antiferromagnetic interactions via cyano-bridges. Because of semi-coordination coupled with pseudo Jahn-Teller elongation and electrostatic interaction for 1, the axial Cu-N coordination bond distances of 2.330(7) and 3.092(8) Å are considerably longer than those of equatorial ones in the range from 2.016(6) to 2.030(6) Å. The former bond distances of 1 are intermediate values among the related Ni (2.324(6) and 3.120(8) Å) and Pt (2.34(1) and 3.09(1) Å) complexes.     

Influence of Fluoride on Rat Kidney Antioxidant System: Effects of Methionine and Vitamin E

The aim of the study has been to determine and compare the influence upon the kidney antioxidative system, exercised by administration of vitamin E, and vitamin E in combination with methionine, under conditions of oxidative stress induced by sodium fluoride. The experiment was carried out on Wistar FL rats (adult males) that, for 35 days, were administered water, NaF, NaF with vitamin E, or vitamin E with methionine (doses: 10 mg NaF/kg of body mass/24 h, 3 mg vitamin E per 10 μl per rat for 24 h, 2 mg methionine per rat for 24 h). The influence of administered sodium fluoride and antioxidants upon the antioxidative system in kidney was examined by analyzing the concentration of malondialdehyde (MDA) and the activity of the most important antioxidative enzymes (SOD, total and both its isoenzymes, GPX, GST, GR, and CAT). The studies carried out confirmed the disadvantageous effect of the administered dose of NaF upon the antixodiative system in rats (increase in the concentration MDA, decrease activity of all antioxidative enzymes). The administration of vitamin E increased the activity of studied enzymes with the exception of glutathione reductase GR; it also reduced the procesess of lipid peroxidation. It has been found that combined doses of vitamin E and methionine were most effective in inhibiting lipid peroxidation processes. The results confirmed the antioxidative properties of methionine.     

多马胺能药物对鲇鱼促性腺激素（GtH）分泌活动的影响

以珠江流域鲇鱼（silurus asotus)为实验材料,研究了多巴胺（DA）能药物（DA及其D－2型受体拮抗物 ,DOM）对鲇鱼促性腺激素（GtH)释放的影响,结果表明,在性腺发育的各个时期,单独注射DOM（5ug/g)均不能显著提高鲇鱼血液基础GtH水平,当DOM与LHRH－A联合注射时能显著增强LHRH－A刺激GtH释放的作用;DA只能抑制GnRH诱导的GtH释放,对基础GtH释放无抑制作用,这种生殖内分泌调节方式与鲇形目的革胡子鲇（Clarias gariepinus)和大鳍Hu（Mystus macropterus)相似,而与鲤形目的鲁科（Cyrpindiae)鱼类不同。     

Reorientation of Microfibrils and Microtubules at the Outer Epidermal Wall of Maize Coleoptiles During Auxin-Mediated Growth

Auxin-mediated elongation growth of isolated subapical coleoptile segments of maize (Zea mays L.) is controlled by the extensibility of the outer cell wall of the outer epidermis (Kutschera et al., 1987). Here we investigate the hypothesis that auxin controls the extensibility of this wall by changing the orientation of newly deposited microfibrils through a corresponding change in the orientation of cortical microtubules. On the basis of electron micrographs it is shown that cessation of growth after removal of the endogenous source of auxin is correlated with a relative increase of longitudinally orientated microfibrils and microtubules at the inner wall surface. Conversely, reinduction of growth by exogenous auxin is correlated with a relative increase of transversely orientated microfibrils and microtubules at the inner wall surface. These changes can be detected 30–60 min after the removal and addition of auxin, respectively. The functional significance of directional changes of newly desposited wall microfibrils for the control of elongation growth is discussed.     

Combination of dihydromyricetin and ondansetron strengthens antiproliferative efficiency of adriamycin in K562/ADR through downregulation of SORCIN: A new strategy of inhibiting P-glycoprotein

Though the advancement of chemotherapy drugs alleviates the progress of cancer, long-term therapy with anticancer agents gradually leads to acquired multidrug resistance (MDR), which limits the survival outcomes in patients. It was shown that dihydromyricetin (DMY) could partly reverse MDR by suppressing P-glycoprotein (P-gp) and soluble resistance-related calcium-binding protein (SORCIN) independently. To reverse MDR more effectively, a new strategy was raised, that is, circumventing MDR by the coadministration of DMY and ondansetron (OND), a common antiemetic drug, during cancer chemotherapy. Meanwhile, the interior relation between P-gp and SORCIN was also revealed. The combination of DMY and OND strongly enhanced antiproliferative efficiency of adriamycin (ADR) because of the increasing accumulation of ADR in K562/ADR-resistant cell line. DMY could downregulate the expression of SORCIN and P-gp via the ERK/Akt pathways, whereas OND could not. In addition, it was proved that SORCIN suppressed ERK and Akt to inhibit P-gp by the silence of SORCIN, however, not vice versa. Finally, the combination of DMY, OND, and ADR led to G2/M cell cycle arrest and apoptosis via resuming P53 function and restraining relevant proteins expression. These fundamental findings provided a promising approach for further treatment of MDR.     

Evolution of different oligomeric glycyl-tRNA synthetases

There are two oligomeric types of glycyl-tRNA synthetases (GlyRSs) in genome, the alpha2beta2 tetramer and alpha2 dimer. Here, we showed that the anticodon-binding domains (ABDs) of dimeric and tetrameric GlyRSs are non-homologous, although their catalytic central domains (CCDs) are homologous. The dimeric GlyRS_ABD is fused to the C-terminal of CCD in alpha-subunit, but the tetrameric GlyRS_ABD is to the C-terminal in beta-subunit during evolution. Generally, one species only contains one oligomeric type of GlyRS, but the both oligomeric GlyRSs with the multiple homologous domains can be observed in Magnetospirillum magnetotacticum genome, nevertheless, these homologous domains are probably from different genomes.     

Structure and function of S-adenosylhomocysteine hydrolase

In mammals, S-adenosylhomocysteine hydrolase (AdoHcyase) is the only known enzyme to catalyze the breakdown of S-adenosylhomocysteine (AdoHcy) to homocysteine and adenosine. AdoHcy is the product of all adenosylmethionine (AdoMet)-dependent biological transmethylations. These reactions have a wide range of products, and are common in all facets of biometabolism. As a product inhibitor, elevated levels of AdoHcy suppress AdoMet-dependent transmethylations. Thus, AdoHcyase is a regulator of biological transmethylation in general. The three-dimensional structure of AdoHcyase complexed with reduced nicotinamide adenine dinucleotide phosphate (NADH) and the inhibitor (1′R, 2′S, 3′R)-9-(2′,3′-dihyroxycyclopenten-1-yl)adenine (DHCeA) was solved by a combination of the crystallographic direct methods program, SnB, to determine the selenium atom substructure and by treating the multiwavelength anomalous diffraction data as a special case of multiple isomorphous replacement. The enzyme architecture resembles that observed for NAD-dependent dehydrogenases, with the catalytic domain and the cofactor binding domain each containing a modified Rossmann fold. The two domains form a deep active site cleft containing the cofactor and bound inhibitor molecule. A comparison of the inhibitor complex of the human enzyme and the structure of the rat enzyme, solved without inhibitor, suggests that a 17° rigid body movement of the catalytic domain occurs upon inhibitor/substrate binding.     

Plasmodium berghei: lack of antimalarial activity of an analogue of folate precursor, 2,4-diamino-6-hydroxymethylpteridine in a mouse model

It was earlier hypothesized that the malarial parasite may convert precursors of folate analogues to synthesize de novo inhibitors toxic to itself, but not to the mammalian cell. It was suggested that one such analogue, 2,4-diamino-6-hydroxymethylpteridine (DAP) may be converted to aminopterin (AMP), a known dihydrofolate reductase inhibitor. In the present study, we evaluated the ability of DAP to inhibit proliferation of Plasmodium berghei NK65 in mice, with(out) folinic acid rescue. Cumulative dosages of DAP ranging from 0.1 to 20 mg/kg bw. administered either orally or intraperitoneally showed no suppression of parasite growth, or gave mild activities that were not statistically significant (P > 0.05). Our findings do not seem to support the hypothesis of selective de novo metabolism of DAP to AMP by the malarial parasite.     

In vitro studies of the rabbit immune system. IV. Differential mitogen responses of isolated T and B cells.

The mitogenic responses of separated rabbit lymphocyte populations functionally analogous to mouse T and B cells have been tested in vitro. Purified T cells were prepared by passage over nylon wool (NW) and purified B cells prepared by treatment with antithymocyte serum and complement (ATS + C). ATS + C kills 70% of peripheral blood lymphocytes (PBL's) and 50% of the spleen cells while passage over NW yields 40% of the applied PBL's and 5–23% of the applied spleen cells. NW-purified T cells from the spleen or PBL's respond fully to concanavalin A (Con A) but have a reduced response to phytohemaglutinin (PHA) and little or no response to goat anti-rabbit immunoglobulin (anti-Ig). PBL's that survive ATS + C (B cells) are stimulated by anti-Ig but not by Con A or PHA. B cells purified from spleen do not respond to Con A or PHA but will respond to anti-Ig under appropriate conditions. A full spleen B-cell response to anti-Ig required removal of Ig produced by the cultures that blocked anti-Ig stimulation. It is concluded that, for rabbit lymphocytes, Con A and PHA are primarily T-cell mitogens and that anti-Ig is primarily a B-cell mitogen. However, the mitogen response of unfractionated PBL or spleen cell populations indicates an overlap in reactivity. This could be due to cells sharing T and B properties, alteration of cell populations by the fractionation procedures used, or recruitment of one population in the presence of a mitogenic response of the other population.     

围隔藻类水华演替过程中二甲基硫化物的含量动态

于2005年6月至7月,研究了海洋围隔不同藻类水华演替过程中二甲基硫化物的含量动态,并考察了相关环境参数对二甲基硫化物含量的影响。2个围隔实验组均出现未知藻水华-硅藻水华-甲藻水华的演替过程,这3次不同藻类水华分别对应了二甲基硫化物含量的3次高峰,表明藻类水华对二甲基硫化物含量有重要贡献。不同藻类水华的贡献有较大差异,甲藻水华的贡献最大,硅藻次之,未知藻类水华的贡献最小。实验结果还表明PO4^3-、NO2^-和NH4^＋主要通过影响藻类生长状态,进而影响DMSP和DMSO的含量;NO2^-和NH4^＋亦可能通过调节DMSP和DMSO在藻细胞内的生理功能,影响DMSP和DMSO的含量;PO4^3-、NO2^-和NH4^＋与DMS含量无显著相关。