Expression of luminescence in Photobacterium phosphoreum: Na+ regulation of in vivo luminescence appearance

In Photobacterium phosphoreum strain 496, growth and luminescence in a complex medium are optimal with 3% NaCl. However, in the same medium with 1% NaCl growth is similar, but the development of bioluminescence does not occur. In cells grown to mid or late-log phase in 1% NaCl, light emission can be triggered by the addition of NaCl, but the time required for its appearance is quite long, at least 30–45 min. The synthesis of m-RNA and protein are required for the development of luminescence, but the long time interval suggests that some intermediate steps are required. The time required is not less in conditioned 3% NaCl medium.     

Analysis of synchronous photon emissions from the bacterium Photobacterium phosphoreum during colony formation from a single cell

Light emission from Photobacterium phosphoreum was analysed during cell growth on an agar plate from a single cell to colony formation. Temporal analysis of image intensified light was set so that a quadratic window covered a single cell. Intensity of light emission from a single cell through colony formation showed an initial decrease, a prolonged lag phase, and then a rapid increase. These responses on an agar plate were similar to those from liquid cultures. The image analysis showed repeated bursts of light emission in the phases when light was increasing and decreasing. Statistical analysis of light emission also emphasized the presence of bursts of light emission, suggesting the metabolic synchronism of luciferase reactions in either a single cell or synchronously divided cells. The repetitive bursts of light occurred in a single cell and continued during the growth phase in which the cell population and the light emission was increasing. In a single cell, however, periodicity of light emission was not defined directly from fast Fourier transformation, although it was indicated on oscillation of mean level of fluctuated light emission, at initial phase of culture on agar plate.     

不同溶剂和保存条件对尾叶悬钩子花色素苷提取及稳定性的影响

对尾叶悬钩子(Rubus caudifolius Wuzhi)鲜果中花色素苷的提取条件、主要化学组分及pH值、温度、没食子酸和Al^3 对其颜色及稳定性的影响进行了分析探讨。结果表明,尾叶悬钩子花色素苷的主要组分可能为矢车菊素-3-葡萄糖苷;pH值和温度影响该花色素苷的色泽及其稳定性,随着pH值和温度的增加,其分解加剧,且花色素苷的分解均遵循动力学一级反应规律;添加不同浓度的Al^3 ,色素溶液的吸光值有所升高,显示出有一定的增色效应,但Al^3 和没食子酸对贮藏期间花色素苷的稳定性及色泽均无明显效果。     

Immunologic response to protein immobilized on the surface of liposomes via covalent azo-bonding

A new method for immobilizing protein on the surface of liposomes is described. Inclusion of $\text{N-(p-}\text{aminophenyl)}$stearylamide in the lipid composition of vesicles resulted In liposomes that could be ‘activated’ by diazotization with NaNO₂/HCl, and subsequently coupled with protein. Using this method $\text{39.7 ? 7.5 μ}\text{g}$ egg albumin / μmol phospholipid has been coupled to multilamellar vesicles composed of phosphatidylcholine, cholesterol, and $\text{N-(p-}\text{aminophenyl}\text{)}$stearylamide in a molar ratio of 15:7.5:1.1. Furthermore, when the immunologic response of mice to egg albumin that was encapsulated in, nonspecifically adsorbed, or covalently linked to liposomes was investigated, only the covalent protein-liposome conjugates elicited pronounced and sustained elevations in antibody titers. These results suggest that the immunoadjuvant effects of liposomes can be maximized by covalently linking protein antigens to their surface.     

Effects of aldehyde and internal ions on bioluminescence expression of Photobacterium phosphoreum

In a complex medium, cells of Photobacterium phosphoreum (strain 496) grow equally well with 1% and 3% NaCl, but luminescence occurs only with 3% NaCl in the medium. However, the suppression of luminescence is not attributable to the lack of luciferase; log phase cells growing in 1% NaCl will develop luminescence following a shift to 3% NaCl, which is accompanied by an increase of intracellular potassium. Tetradecanal stimulates bioluminescence in a 1% NaCl culture, and also in the presence of nalidixic acid, an inhibitor or gyrase. It is thus suggested that the suppression of luminescence in 1% NaCl or in 3% NaCl with nalidixic acid is due to a deficiency in the synthesis of intracellular aldehyde. The increase in intracellular potassium that occurs upon shifting from 1% to 3% NaCl may also relate to aldehyde synthesis gene expression via activation of gyrase, or via an increase in negative supercoiling of the chromosome. However, since an initial decrease of light intensity is still observed during culture even with the addition of tetradecanal, an additional factor related to cell density must also be involved in bioluminescence expression.Abbreviations nal nalidixic acid - nal-r nalidixic acid resistant strain     

A new method for liquid nitrogen storage of phototrophic bacteria under anaerobic conditions

A simple, effective and economical method for the long-term preservation of bacteria in liquid nitrogen under anaerobic conditions is described. As a case example anaerobic photosynthetic bacteria were successfully preserved. Gas tight small screw-cap glass ampoules with butyl rubber septa were used for freezing the specimen anaerobically. During experimental manipulations no anaerobic chamber or glove boxes were required. All teste cultures yielded high recoveries after repeated thawing and during storage. After freezing, survival recoveries of Rhodospirillaceae range from 70–100%, whereas with strict anaerobic strains of Chlorobiaceae and Chromatiaceae a maximum loss of 1–2 log₁₀ counts was observed. No further loss in viability occurred after 1–2 years of storage.The small size of the ampoules and the use of single ampoule for 15–20 repeated retrievals proved economical with respect to storage space and costs.The system is compact and suitable for the preservation of anaerobic phototropic bacteria and other fragile anaerobic microorganisms.     

固定化植物乳杆菌的制备及其发酵条件优化

采用海藻酸钠包埋植物乳杆菌并通过测定固定化细胞发酵清液的抑菌效果,优化得到的固定化最佳工艺条件为:海藻酸钠浓度为3%,CaCl2浓度为1.5%,菌悬液体积为3.5 mL(4.0×108 cfu/mL).固定化细胞重复发酵多批次效果良好.固定化细胞发酵条件优化结果表明:最适pH为7.0,最适温度为36℃,培养基中添加0....     

Acclimation of the photosynthetic response of Chromatium vinosum to light-limiting conditions

The photosynthetic response of the purple sulfur bacterium Chromatium vinosum DSM 185 to different degrees of illumination was analyzed. The microorganism was grown in continuous culture, and samples were taken from the effluent of the culture and incubated at different irradiances to determine the specific rate of sulfur oxidation as a measure of the photosynthetic activity of the organism. The activities obtained were plotted as a function of the specific rate of light uptake, and for each set of data a photosynthesis equation was fitted, which allowed the estimation of P_max (photosynthetic capacity), q_k (the threshold irradiance for light limitation), and m (maintenance coefficient). The results indicated that cells grown under light limitation are able to achieve higher photosynthetic activities than cells grown under light saturation. The photosynthetic capacity (P_max) remained constant under all the conditions of illumination tested, while the maintenance expenses (m) were higher under light limitation. The parameter q_k, on the contrary, decreased considerably at limiting irradiances. Received: 16 January 1998 / Accepted: 7 September 1998     

Activity and storage stability of immobilized glucose oxidase onto magnesium silicate

Glucose oxidase (GOD) was covalently immobilized onto florisil (magnesium silicate) carrier via glutaraldehyde. Immobilization conditions were optimized: the amount of initial GOD per grams of carrier as 5 mg, pH as 5.5, immobilization time as 120 min and temperature as 10 °C. Under the optimized reaction conditions activities of free and immobilized GOD were measured. Free and immobilized GOD samples were characterized with their kinetic parameters, and thermal and storage stabilities. K_M and V_max values were 68.2 mM and 435 U mg GOD⁻¹ for free and 259 mM and 217 U mg GOD⁻¹ for immobilized enzymes, respectively. Operational stability of the immobilized enzyme was also determined by using a stirred batch type column reactor. Immobilized GOD was retained 40% of its initial activity after 50 reuses. Storage stabilities of the immobilized GOD samples stored in the mediums with different relative humidity in the range of 0–100% were investigated during 2 months. The highest storage stability was determined for the samples stored in the medium of 60% relative humidity. Increased relative humidity from 0% to 60% caused increased storage stability of immobilized GODs, however, further increase in relative humidity from 80% to 100% caused a significant decrease in storage stability of samples.     

Osmotic control of luminescence and growth in Photobacterium leiognathi from ponyfish light organs

Osmolarity was found to control the luminescence and growth of Photobacterium leiognathi strain LN-1a isolated from the light organ of the ponyfish Leiognathus nuchalis (family Leiognathidae). Low osmolarity (ca. 400 mOsm) stimulated luminescence per cell 80 to 100-fold to a level (ca. 2.0×10⁴ quanta·s^-1·cell^-1) equal to that of bacteria taken directly from the light organ and increased the level of luciferase per cell 8 to 10-fold compared to high osmolarity (ca. 800 mOsm). Conversely, high osmolarity stimulated oxygen uptake and growth rate 2 to 4-fold compared to low osmolarity. Of 21 additional tested strains of P. leiognathi from light organs of 9 other ponyfish species, all responded similarly. Low osmolarity may be a host control factor that functions to stimulate the luminescence and restrict the growth of ponyfish light organ bacteria in situ.     

Growth and luminescence of luminous bacteria promoted by agents of microbial origin

The examination of four species of luminous bacteria Photobacterium leiognathi, Photobacterium phosphoreum, Vibrio fischeri and Vibrio harveyi has enabled us to reveal some nutrient medium components effecting growth, luminescence intensity and luciferase synthesis. These agents are nucleic components (nucleotides, nucleosides and amine bases), amino acids and vitamins, which are part of hydrolysates from the biomass of various lithotrophic microorganisms, hydrogen-oxidizing, ironoxidizing and carboxydobacteria. The effect of promoting agents essentially alters the physiological state and ultrastructure of the cells of luminous bacteria and increases luciferase biosynthesis two- to three-fold compared to a control.     

Effect of storage conditions on the survival of two potential biocontrol agents of nematodes,the fungi Paecilomyces lilacinus and Pochonia chlamydosporia

The nematophagous fungi Paecilomyces lilacinus and Pochonia chlamydosporia have been extensively studied as biological control agents for plant-parasitic nematodes. This study describes the formulation of alginate pellets containing mycelia of these fungi and also describes the effect of storage conditions on shelf-life of the pellets. The shelf-lives of P. lilacinus and P. chlamydosporia, which were measured monthly for 6 months, were significantly improved at low temperatures and low water activity (a _w) values (<0.33). Vacuum did not affect the viability of the formulated P. lilacinus but increased the viability of P. chlamydosporia. Carbon dioxide reduced the activity of P. lilacinus as compared to ambient air but increased the activity of P. chlamydosporia. Nitrogen, however, significantly improved the viability of both fungi. The optimal parameters of each factor for our formulation of P. lilacinus and P. chlamydosporia included a temperature range of 4 to ?20°C, a _w=0.12, and a nitrogen-filled atmosphere.     

Enhancement of shelf life of tomatoes by postharvest herbal treatment,during storage under ambient conditions

Fruits and vegetables are the most perishable agricultural commodities, and the postharvest loss of these is tremendous. The objective of this study is to reduce postharvest losses of perishables with a very simple approach. The study was conducted to find out the effect of postharvest herbal treatment on shelf life of tomatoes under ambient conditions. Three different herbal formulations of Curcuma aromatica (A), Glycyrrhiza glabra (B) and Garcinia indica (C) each at concentration of 1% w/v were studied. The tomatoes stored were evaluated on 7th and 14th day for physicochemical parameters (viz. Vitamin C, Titrable acidity, pH and total soluble solids) and percent spoilage. It was observed that the formulation of G. indica was found to be most effective. Tomatoes treated with formulation of G. indica were rated for organoleptic evaluation and got very good ratings. This study has revealed the possibility of utilisation of herbal formulations to reduce postharvest losses of tomatoes.     

不同贮藏条件对五味子质量的影响

基于多元活性成分同时测定结合多元统计分析探讨不同贮藏条件对五味子药材质量的影响。采用超快速液相色谱-三重四极杆/线性离子阱质谱(UFLC-QTRAP-MS/MS)同时测定不同贮藏条件(包装材料,贮藏温度)五味子中木脂素(五味子酯乙、五味子醇乙、五味子丙素、五味子乙素、五味子甲素、五味子酯甲、五味子醇甲、五味子酚、戈米辛D、戈米辛J、当归酰基戈米辛H)及有机酸(L-苹果酸、酒石酸、原儿茶酸、奎宁酸)共15种指标成分的含量;根据15种目标成分的含量,用灰色关联度分析和TOPSIS法对不同贮藏五味子进行综合评价。结果表明,15种化合物在一定浓度范围内均呈现良好的线性关系,相关系数均大于0.999 1;精密度、重复性和稳定性良好;平均加样回收率在96.64%～99.96%之间,RSD均小于5%。灰色关联度分析中r_i的最大差异较小为57.5%,TOPSIS法中C_i值的最大差异较大为81.3%,两种结果均显示S4、S3、S1的综合质量较好,五味子的适宜贮藏条件为以聚乙烯密封袋为外包装存放于阴凉库。所建立的方法准确、可靠,可用于五味子药材内在质量的综合评价,本研究可为五味子适宜储藏条件的优选提供基础资料。     

Dynamics of luminescence characteristics of Haematococcus lacustris cultures in different cultivation conditions

Luminescence of microalgae cultures is a valuable property for the fast diagnostics of their physiological state; however, it has been rarely used in algaculture practice. In this work, luminescence spectrum characteristics of two-stage batch cultures of the green carotenogenic microalga Haematococcus lacustris (Girod-Chantrans) Rostafinski 1875 (Chlorophyceae, Chlamydomonadales) under conditions of autotrophic and mixotrophic growth were investigated. The dynamics of the heterotrophy indices in cultures at different stages of their development in different growth media was determined. The transition of H. lacustris cultures from the initially autotrophic to mixotrophic growth regime was registered during the induction of the astaxanthin biosynthesis by complex physicochemical stressing, including nutritional deficiencies, exposure to high concentrations of sodium acetate and chloride and increased illuminance and temperature. The applicability of luminescence spectrometry in vivo for a rapid assessment of the state of H. lacustris cultures in various growth media and with different methods of secondary carotenogenesis induction was shown. The results obtained can be used in experimental studies on optimizing cultivation methods for this species, as well as for the express control of the physiological state of its industrial cultures.