中国若干地区森林土壤对酸雨缓冲能力的探讨

为了探讨我国若干地区森林土壤对酸雨的缓冲能力,本文在对我国几个典型森林地带的土壤样品进行矿物分离富集等基础上用x射线粉末衍射法进行矿物学研究;本实验采用丙酮-二碘甲烷量液体系对土壤中的细砂级矿物进行密度梯度分级处理,同时对土壤中的淤泥样品进行严格的分选,集中<2μm的粘粒,而后分别作矿物分析鉴定;根据其结果,对各地区森林土壤中的细砂及粘土矿物组成作了比较,并对这些地区土壤的风化潜力及其对酸雨的缓冲能力作了讨论。     

THE USE OF MILLIPORE FILTERS IN ULTRASTRUCTURAL STUDIES OF CELL CULTURES AND VIRUSES

A technique is described for embedding tissue culture cells that have been adsorbed or grown on Millipore filters. The acetone used during the embedding process rendered the filters transparent so that specific areas or cells could be chosen with the aid of the light microscope. Lymphoblastoid cells processed on the filters possessed well-defined plasma membranes and microvilli which were rarely present in cells from parallel cultures that were prepared by pelleting in the centrifuge. Fibroblast cells grown on filters retained their elongated appearance, in contrast to the rounded cells in pelleted preparations. Millipore filters were also used as a means of embedding virus pellets for sectioning. Preparations containing as few as 4 x 10⁸ virus particles were suitable for study by the filter technique. Crude tissue-culture harvests of vaccinia virus and purified preparations of Rauscher murine leukemia and adeno-satellite viruses were successfully examined.     

THE FAILURE OF PHENOL TREATED ESCHERICHIA COLI TO GROW ON MEMBRANE FILTERS

SUMMARY: Counts of Escherichia coli were done on nutrient agar (control), on membrane filters on nutrient agar and on membrane filters on filter paper pads. With untreated bacteria counts were similar under all conditions, though membrane filters on nutrient agar tended to give slightly low counts. Phenol treated bacteria gave much lower counts when membrane filters were used: the mean counts for 3 strains of the test organism with filters on nutrient agar varied from 35–65% of the control, while counts with filters on filter paper pads were somewhat lower, varying from 30–47% of the control. The low counts on membrane filters on filter paper pads were not due to adsorption of phenol by the filters or to a low concentration of nutrients in the growth medium.     

A STUDY OF THE BIOLOGY AND CONTROL OF ANISOPUS FENESTRALIS (SCOPOLI, 1763), A FLY ASSOCIATED WITH SEWAGE FILTERS

In work on the control of the sewage fly Anisopus fenestralis (Scopoli, 1763), it was shown that the larval phase was considerably lengthened by limiting the food supplied. The effects of food supply and temperature are considered in relation to the incidence of the adult fly in the filters. The assessment of the fly population of sewage filters by tray traps, as previously used by other workers, was investigated. Both light and temperature were found to affect the number of A. fenestralis entering the trays: it is concluded that although the trays do not accurately assess the A. fenestralis population of a bed, nor measure the rate of emergence from the bed, they are of value in assessing the relative effect of different control measures. In the filters the period of maximum abundance was during the spring, followed by a period of reduced numbers throughout the summer, with a recovery in the autumn giving relatively high numbers throughout the winter. Emergence of A. fenestralis from the filters is influenced by climatic factors, especially temperature and light; a diurnal variation in the rate of emergence was also observed. Because of this effect of temperature on emergence, the flies were only present above the filters in the warmer periods of the year; and because of the reduced numbers in the filters in the summer, the flies were only abundant above the beds during the spring and early summer and in the autumn. BHC applied as a water-dispersible powder was more effective than in the form of an emulsion. It was also most effective when used against the larval phase.     

A NEW PROCEDURE FOR THE MEASUREMENT OF ACID-SOLUBLE GLUTAMINE OF TISSUE WITH PARTICULAR REFERENCE TO THE BRAIN

—A simple method is described for the measurement of free brain glutamine by spectrophotometric means, without prior separation by either paper or column chromatography. Through the application of this method, it was also possible to obtain an approximate value for the combined concentrations of glutamic acid, y-aminobutyric acid and glutathione in brain.     

THE METABOLISM OF TRITIATED DOPAMINE IN REGIONS OF THE RAT BRAIN IN VIVO—I

Abstract— A simple combination of acid- and base-exchange resin columns enabled a more complete separation of amine, acid and neutral metabolites of catecholamines from individual small brain samples to be made. Fractions containing individual catecholamines or metabolites were obtained in aqueous eluates suitable for fluorimetric or radioisotopic analysis. With consistent intraventricular injection and brain dissection techniques, this separation method enables a study of the metabolism of catecholamines in regions of the rat brain and the effects of drugs on this metabolism.     

DIFFUSION CHAMBER CULTURE OF A SINGLE EMBRYOID BODY FROM THE TESTICULAR TERATOMA OF STRAIN 129 MOUSE

When single embryoid bodies of teratocarcinoma OTT 6050 were cultured by the diffusion chamber technique in the peritoneal cavity of a mouse, they lost their characteristic three-dimensional structure early in the culture period and proliferated logarithmically up to the 60th day of culture with a doubling time of 3.7 days, forming cell layers that adhered to the surface of the membrane filters of the diffusion chamber. They continued further to proliferate at a lower rate up to the 80th day of culture. At the 60th day, many round cells, classified by diameter into about three classes, were observed on the membrane filters. The tumorigenicity of these cells derived from the chamber cultures was much less than that of embryoid bodies injected directly into the abdominal cavity, judging from the number of days the mice survived.     

A ZONAL ROTOR METHOD FOR THE PREPARATION OF MICROPEROXISOMES FROM EPITHELIAL CELLS OF GUINEA PIG SMALL INTESTINE

A method is described for the preparation of catalase particles from homogenates made from suspensions of epithelial cells of the small intestine of the guinea pig. Electron microscope examination of the preparations revealed the presence of small diaminobenzidine-positive particles measuring 0.1–0.3 nm in diameter and resembling the microperoxisomes observed by Novikoff and Novikoff (1972. J. Cell Biol. 53:532.). Analytical data upon which the method is based are presented. The technique consisted of a rate zonal separation of microperoxisomes from large particles followed by an isopycnic separation from less dense organelles. Application of the method yielded microperoxisomes purified between 20- and 30-fold.     

THE CHANGE IN INOSITOL PHOSPHATES DURING THE RIPENING OF RICE GRAINS

Inositol phosphates were analyzed by ion exchange chromatographyusing the chloride ion gradient elution method, which was foundto be satisfactory for complete separation of individual inositolphosphates. Only inositol-hexa-phosphate and inorganic phosphatewere recognized in the ripening rice grains. Inositol hexa-phosphateshowed a markedly rapid increase in the early ripening phasefollowed by the gradual increase in the later phase, while inorganicphosphate decreased in the later stages of the ripening. (Received April 15, 1964; )     

METHODS OF ASSESSING THE SPORICIDAL EFFICIENCY OF AN ULTRA-HIGH-TEMPERATURE MILK STERILIZING PLANT I. EXPERIMENTS WITH SUSPENSIONS OF SPORES IN WATER

SUMMARY: A method of assessing the sporicidal efficiency of a UHT milk sterilizing plant operating on water is described. Water heavily contaminated with spores of a strain of Bacillus subtilis was filtered, after treatment in the plant, through membrane filters and the surviving spores estimated by incubation of the membranes in nutrient agar. With this plant a temperature of c . 135° caused a 99·99999% kill of B. subtilis spores. Confirmation of the lethal effects of temperatures above 135° was obtained by passing treated water into 10 gal churns containing sterile concentrated nutrient broth and incubating the churns.     

Artificial molecular sieves and filters: a new paradigm for biomolecule separation

Patterned regular sieves and filters with comparable molecular dimensions hold great promise as an alternative to conventional polymeric gels and fibrous membranes to improve biomolecule separation. Recent developments of microfabricated nanofluidic sieves and filters have demonstrated superior performance for both analytical and preparative separation of various physiologically relevant macromolecules, including proteins. The insights gained from designing these artificial molecular sieves and filters, along with the promising results gathered from their first applications, serve to illustrate the impact that they can have on improving future separation of complex biological samples. Further development of artificial sieves and filters with more elaborate geometrical constraints and tailored surface functionality is believed to provide more promising ideals and results for biomolecule separation, which has great implications for proteomic research and biomarker discovery.     

海藻中有机碘的研究Ⅰ.海藻中有机碘含量测定

采用国际上目前通用的差减法来计算海藻中的有机碘,即首先测定海藻中的总碘和无机碘,其差减值为有机碘.碘的测定采用了碘离子选择电极法和中子活化法作为对照。在此基础上,还测定了新鲜海带中碘的含量、分布以及有机碘和无机碘的比例。研究结果表明,海带中碘的平均含量占鲜重的0.133％,其中88％的碘是以碘离子的形式存在,有机碘只占总碘的12％,同时海带不同部位碘的含量不同,叶部外缘含碘较多,是叶中部的2倍左右,尤其叶尖部的含量达到鲜重的0.183％。而有机碘的含量分布规律则不同,有机碘的含量在靠近根部的位置较高,为鲜重的13.9％。这种分布特点可能与海带的生命活动规律有关。     

超氧物歧化酶(SOD)在大豆下胚轴线粒体内的定位

本文介绍一种简单有效的制备、分离植物线粒体分部的方法,根据这一方法证明了大豆下胚轴线粒体内的 SOD 主要在基质可溶性部分,是属于对氰化物不敏感的 Mn-SOD,它占线粒体 SOD 总活性的80%,其余 SOD 活性主要在线粒体的膜间空间,约占总活性的16%。结果表明,SOD 在植物线粒体内的分布和定位与动物组织相似。     

一种独立分量分析的迭代算法和实验结果

介绍盲信源分离中一种独立分量分析方法,基于信息论原理,给出了一个衡量输出分量统计独立的目标函数。最优化该目标函数,得出一种用于独立分量分析的迭代算法。相对于其他大多数独立分量分析方法来说,该算法的优点在于迭代过程中不需要计算信号的高阶统计量,收敛速度快。通过脑电信号和其他信号的计算机仿真和实验结果表明了算法的有效性。     

APPLICATION OF THE MEMBRANE FILTER FOR THE QUANTITATIVE STUDY OF TRANSFORMATIONS WITH PARTICULAR REFERENCE TO PHENOTYPIC EXPRESSION OF AN ERYTHROMYCIN-RESISTANCE MUTATION.

Iyer, V. N. (University of Rochester, Rochester, N.Y.). Application of the membrane filter for the quantitative study of transformations with particular reference to phenotypic expression of an erythromycin-resistance mutation. J. Bacteriol. 84:326-330. 1962.-A technique using membrane filters for quantitative studies of transformation of pneumococci is described and some possible applications discussed. This method has been found amenable to the study of the integration and phenotypic expression of an erythromycin-resistance mutation of pneumococci which is characterized by a low frequency of transformation and delayed expression. The expression of survival occurs prior to the expression of colony-forming ability in the presence of erythromycin.     

THE EFFECT OF ENUCLEATION ON THE DPN LEVEL OF AMEBA

1. Amebae contain DPN at levels of from 1 to 4 x 10^–13 moles per cell. 2. Following enucleation, nucleate and enucleate halves continue to have equal DPN contents over the six day period studied. Similarly, starving whole amebae maintain their DPN level over this period. 3. No reduced DPN could be detected in these aerobic animals. This remained true for whole amebae and for nucleate and enucleate halves over 5 days of starvation. 4. A method is described for the preparation and rapid separation of nucleate and enucleate ameba halves, based on a response of amebae to light.     

Magnetic separations in biotechnology

Magnetic separation techniques provide probably the most rapid and convenient method of separating certain particles from dilute suspensions, especially those that might block columns or filters. This and other applications of magnetism, including cell sorting and product recovery are discussed.     

RETENTION OF DISSOLVED COMPOUNDS BY MEMBRANE FILTERS AS AN ERROR IN THE 14C METHOD OF PRIMARY PRODUCTION MEASUREMENT1

Membrane filters retain ¹⁴C bicarbonate, ¹⁴C glycollate, and other ¹⁴C labeled substances from filtrates of algal cultures and lake water. By refiltering different volumes of the filtrate from algal cultures and from lake water after incubation with ¹⁴C bicarbonate, it was shown that the labeled material retained was not proportional to volume but showed a saturation effect with increasing volume filtered. When the radioactivity retained by a filter is divided by the volume filtered, decreasing values are obtained with increased volume filtered. This radioactivity may represent a significant addition to the radioactivity in particulate material on the filters, resulting in a similar type of curve when different volumes of lake water or cultures are filtered. Values of radioactivity per milliliter were constant using Chlorella in Chu 10 medium. However, the curve could, be obtained by increasing pH and bicarbonate concentrations in the medium and on resuspending the algae in Lake Ontario (winter) filtrate. The values of cpm/ml retained from filtrates were low in Cryptomonas cultures and the curve was not obtained unless population density was reduced, thus increasing the relative contribution to the radioactivity on the filters. The curve was not always obtained in lake water. It was significant in 10 out of 14 experiments in Lake Ontario and in 2 out of 5 experiments in Grenadier Pond. Changes in lake water rather than in experimental techniques were probably responsible. On 2 occasions when values of cpm/ml were constant in Lake Ontario, addition of sodium bicarbonate without a pH change resulted, in a significant curve. Our experiments do not disprove the possibility of cell damage during Millipore filtration, however, it has been shown that ¹⁴C labeled substances retained from solutions can account for the entire range of decreasing values as a function of volume filtered.     

应用光敏生物素标记核酸探针鉴定分枝杆菌的研究

用光敏生物素标记非结核分枝杆菌临床分离株及标准分枝杆菌全染色体ＤＮＡ制成探针,与已知标准牛分枝杆菌（ＢＣＧ株）及不同种的非结核分枝杆菌ＤＮＡ杂交,可快速将分支杆菌鉴定到种,同时以大肠埃希氏菌做阴性对照,显示良好的特异性和准确性。此种方法具有鉴定速度快、操作简便、稳定性好及对人体无害等特点,适用于结核杆菌和非结核分枝杆菌的菌种鉴定。     

A rapid filtration assay for cAMP

The receptor-binding assay for cAMP was improved by using polyethylenimine-treated glass filters. A polyethylenimine-treated glass filter has high protein binding capacity. This high capacity allows an increase in the amount of protein per assay tube and the use of a crude preparation, such as a beef heart extract, as specific binding protein instead of a purified protein, which has been used in the classical filtration assays involving cellulose ester filters. Since the time required for the separation of the protein-cAMP complex and the free nucleotide can be shortened by the use of polyethylenimine-treated filters, the dissociation of the bound ligand during the separation procedure, which is a serious problem with other modified assay methods involving charcoal adsorption, is minimized. Filtration through polyethylenimine-treated glass filters also gives low blanks and prevents the loss of protein or ligand due to breakage of the filters, which is often observed with fragile cellulose ester membranes. In consequence, this simple and rapid filtration assay allows more accurate and reproducible determinations.