钝顶螺旋藻品系6的生物学特性

本文报道了钝顶螺旋藻(Spirulina platensis.)品系6在室内的培养技术。提出本品系室内培养最适温度在26—30˚C。当光照强度不同时,所获生物量不同。用Pinevitch (1970年) 的方法培养在1／2浓度下生长最佳。它的粗纤维含量较低,认为是饲喂海珍品幼体的理想饵料, 是适于温带生长的螺旋藻品系之一。     

抑制螺旋藻胞内核酸酶酶活的研究

有效抑制胞内核酸酶的活性对提高外源DNA导入和稳定表达具有重要作用,本文通过对钝顶螺旋藻A9、抗刀豆氨酸（CS）突变株A9c、藻体长直型A9L这3种藻株胞内核酸酶活性的研究发现,在培养液中添加EDTA或不同温度不同时间处理藻丝体,都能明显抑制3种藻株胞内核酸酶的活性,并对合适的EDTA浓度、合适的处理温度和时间进行了探讨。     

3种钝顶螺旋藻株胞内核酸酶活性效果研究

取钝顶螺旋藻A9、抗刀豆氨酸(CS)突变株A9c、藻体长直型 A9L的无菌纯藻藻株胞内核酸酶粗提取液,分别对λ-DNA或p8760进行酶切消化后研究酶活.对于A9藻株,p8760更适于作为酶切底物进行酶活研究;酶切最适反应温度为37～45℃,酶切最适反应时间为3h,50℃开始酶活被抑制;A9c藻株酶切最适反应温度为37℃,酶切最适反应时间为3～4h,45℃开始酶活被抑制;A9L藻株,λ-DNA更适于作为酶切底物进行酶活研究,酶切最适反应温度为37～55℃,酶切最适反应时间为2～3h,60℃开始酶活被抑制.对此3种无菌藻株胞内核酸酶活性效果的初步研究表明,藻株形态的变异或抗氨基酸类似物突变,都会影响和改变其胞内核酸酶的活性,这些可为控制胞内核酸酶对螺旋藻转基因操作的影响和选择合适的藻株用于螺旋藻的遗传转化奠定一定的基础.     

Physico-chemical parameters influencing DNase activity of the cyanobacterium Spirulina platensis

The effects of temperature, Mg2+, EDTA concentration and rinsing on extra- and intra-cellular DNase activity of Spirulina platensis strain SSP-14, were investigated. The results indicate that the tested strain contains very high extra- and intracellular DNase activity, which actually hinders the transfer of foreign gene(s) to S. platensis, a cyanobacterium with multiple economic potentials. The extracellular DNase activity could easily be removed by rinsing the cells with Zarrouk medium more than once. The intracellular DNase activity could also be inhibited by (1) removal of Mg2+, (2) maintaining EDTA concentration above 1 mmol l(-1), and (3) manipulating below 0-4 degrees C, during all the incubation procedures. We suggest that, by using one or more of, or combining, all those experimental conditions, the chances of foreign DNA attempted to be introduced into S. platensis without being digested would be increased.     

In vitro antibacterial activity of laboratory grown culture of Spirulina platensis

The hexane, ethyl acetate, dichloromethane, methanol extracts and spent media (extracellular substances) were tested in vitro for their antibacterial activity for which one Gram-positive bacterium (Staphylococcus aureus) and four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumoniae) were used as test organisms. The methanol extract showed more potent activity than other organic extracts, spent medium of the culture exhibited little activity against E. coli only. No inhibitory effect was found against Klebsiella pneumoniae.The broth microdilution assay gave minimum inhibitory concentrations (MIC) values ranging from 1 to 512 μg/ml. The MIC of methanol extract against S. aureus and E. coli were 128 μg/ml and 256 μg/ml, respectively.     

Antimicrobial activity of polyphenolic compounds from Spirulina against food-borne bacterial pathogens

Food-borne drug-resistant bacteria have adverse impacts on both food manufacturers and consumers. Disillusionment with the efficacy of current preservatives and antibiotics for controlling food-borne pathogens, especially drug-resistant bacteria, has led to a search for safer alternatives from natural sources. Spirulina have been recognized as a food supplement, natural colorant, and enriched source of bioactive secondary metabolites. The main objectives of this study were to isolate polyphenolic compounds from Spirulina and analyze their antibacterial potential against drug-resistant food-borne bacterial pathogens. We found that fraction B of methanol extract contained a high quantity of polyphenols exhibiting broad spectrum antimicrobial effects against drug-resistant food-borne bacterial pathogens. Potential secondary metabolites, such as benzophenone, dihydro-methyl-phenylacridine, carbanilic acid, dinitrobenzoate, propanediamine, isoquinoline, piperidin, oxazolidin, and pyrrolidine, were identified by gas chromatography and mass spectrophotometry (GCMS). These metabolites are active against both gram-positive and gram-negative pathogens. Our work suggests that phenolic compounds from Spirulina provide a natural and sustainable source of food preservatives for future use.     

Biological activity of probiotic microorganisms

Adaptation of bifidobacteria and lactic acid bacteria to nutrient media with increased concentrations of bile (1%) and protein substrates of animal origin allowed the variants resistant to bile and displaying a high production of proteolytic enzymes (active within the pH range of 2.5-9.0) to be selected. Administration of the preparations involving the selected bifidobacteria and lactic acid bacteria assisted in the normalization of the intestinal microflora and activation of protein metabolism in the organism of animals. Specifically, it increased the total protein level in blood serum and redistributed protein fractions, increasing the content of globulins and decreasing albumin concentration.     

Biological activity of gibberellin analogues

In order to determine the significance of the C-6 carboxyl group for the biological activity gibberellin A₃, 6-epigibberellin A₃, 7-norgibberellin A₃, 6-methyl-7-norgibberellin A₃, and 7-homogibberellin A₃ were studied using dwarf pea, dwarf maize, dwarf rice, dwarf barley and -amylase bioassays. All gibberellin A₃(GA₃)derivatives tested were considerably less active than GA₃. In all biossays, 6-epi-GA₃ showed a low activity of the same order, whereas 6-methyl-7-nor-GA₃ was inactive. Surprisingly, 7-nor-GA₃ had some activity in the dwarf rice (root application), dwarf barley, and -amylase bioassay, in contrary to its low potency in the dwarf pea, dwarf maize, and dwarf rice (micro drop) bioassay. 7-Homo-GA₃ was primarily active in the dwarf maize, dwarf barley and dwarf rice bioassay. It also caused antigibberellin effects in dwarf rice. The results demonstrate that the C-6 carboxyl group is not absolutely essential for biological activity of gibberellins. The different activities of 7-nor-GA₃ observed in the various test systems may indicate that the C-6 carboxyl group is a structural requirement more for uptake and/or transport processes than for receptor affinity.Abbreviation GA₃ gibberellic acid     

Biological activity of alpha-alkyl-amino acids

Summary A series of alpha-alkyl-amino acids were tested for some biological functions in the mouse (OF-1 Himberg) by adding them to the animal chow (30 mg/kg/day) for a period of six weeks. No differences in fluid or food uptake could be observed during the feeding period, as compared to a control group. Histology of liver and kidney did not show any changes. Testing routine clinical chemical parameters (serum substrates and enzymes) revealed the following changes: Hex-Ala and But-Abu increased the serum glucose levels. But-Abu dramatically lowered the triglycerides. Serum albumin was increased by Pent-Ala, Me-Val, and But-Abu. LDH was inhibited by But-Abu.     

Biological activity of probiotic microorganisms

Adaptation of bifidobacteria and lactic acid bacteria to nutrient media with increased concentrations of bile (1%) and protein substrates of animal origin allowed the variants resistant to bile and displaying a high production of proteolytic enzymes (active within the pH range of 2.5–9.0) to be selected. Administration of the preparations involving the selected bifidobacteria and lactic acid bacteria assisted in the normalization of the intestinal microflora and activation of protein metabolism in the organism of animals. Specifically, it increased the total protein level in blood serum and redistributed protein fractions, increasing the content of globulins and decreasing albumin concentration.     

Biological activity of galactoglucomannan-derived oligosaccharides

A mixture of galactoglucomannan-derived oligosaccharides (GGMOs), degree of polymerization 4–8, (1.2 M and 12 M) stimulated the viability of spruce [Picea abies (L.) Karst] embryos predominately on media supplemented with indole-3-acetic acid: zeatin (0.011, 10.01 mg · 1^-1), at pH 5.O. Their effects on the development and morphogenesis of embryos were dependent on the culture conditions used. These GGMOs also improved the viability of spruce protoplasts when applied at the same concentrations in combination with 1-naphthaleneacetic acid, and to a lesser extent with 2,4-dichlorophenoxyacetic acid at pH 3.8. Viability was also maintained in the presence of GGMOs when the growth hormones were absent; however, the efficiency of protoplast division was low.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-naphthaleneacetic acid - GGMOs galactoglucomannan-derived oligosaccharides - IAA indole-3-acetic acid - zeatin 6-[4-hydroxy-3-methyl-but-2-enylamino]purine This research was supported by the Slovak Grant Agency for Science.     

Biological activity of vanadium compounds

Vanadium compounds are characterised by a broad spectrum of action in vivo and in vitro. Their insulin-mimetic activity is manifested in their ability to normalize changes observed in both clinical and experimental diabetes (i.e. hyperglycaemia, hyperlipidaemia, lowered cell sensitivity to insulin) through the regulation of carbohydrate and lipid metabolism and the removal of secondary symptoms of this disease (as e.g. retinopathy, cardiomyopathy, nephropathy). Nevertheless, vanadium is considered to be a toxic element in both cationic and anionic form, although the latter type has more serious side effects. This is accounted for by the faster absorption of anionic forms, although the chemical structure, geometry, and the manner of synthesis of its derivatives also contributes to this elevated toxicity. Besides their antidiabetic properties, vanadium derivatives have also been observed to influence processes related to mitogenic cell responses (apoptosis, proliferation, neoplastic transformation). However, both anti-and pro-neoplastic properties of vanadium are reported.     

螺旋藻对小鼠SOD和GSH—Px活力的影响

采用微量测定法,观察螺旋藻对３２只昆明种小白鼠全血中超氧化物歧化酶（ＳＯＤ）和谷光甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性的影响。结果表明,灌胃螺旋藻试验组（ＳＯＤ）活性（１５７７．１６±１６９．８８ＩＵ／ｇＨｂ）,与相应对照组（１３３６．２７±１５８．２３ＩＵ／ｇＨｂ）比较,ＧＳＨ－Ｐｘ活性（２８．３３±２．３７ＩＵ／ｍｌ）与相应对照组（２４．８７±３．２６ＩＵ／ｍｌ）比较,差别均有非常显著意义（Ｐ＜０．０１）;提示螺旋藻有提高动物ＳＯＤ和ＧＳＨ－Ｐｘ活性的功效     

Biological activity ofTreponema hyodysenteriae hemolysin

The biological properties ofTreponema hyodysenteriae hemolysin (TH), which in some aspects resembles streptolysin S, were studied. Aside from different erythrocyte species, TH had no lytic activity on prokaryotic (protoplasts and spheroplasts) and eukaryotic (Chinese hamster ovary and spleen) cells. However, TH decreased the response of spleen cells to concanavalin A and lipopolysaccharide. In vivo, TH was found to induce fluid accumulation in ligated rat ileal loops as well as histological modifications similar to those observed in the swine dysentery. These results further differentiate TH from streptolysin S, and suggest that it is a new oxygen-resistant hemolysin produced by a Gram-negative bacterium.