A new method for rapid identification of influenza virus isolates.

With the use of bacteria sensitized by influenza virus strain-specific antisera, virus isolates can be identified rapidly. One drop of virus suspension is mixed with one drop of sensitized bacteria on a slide that is then agitated; reaction occurs within 10 minutes. The test is subtype-specific. The mehod is based on the fact that the cell wall of the Cowan type 1 strain of Staphylococcus aureus contains abundant quantities of an antigen, known as protein A, that reacts with the IgG molecule by binding it in such a manner that the antibody-combining sites remain free. If an antigen homologous to the antibody coated on the surface of the bacteria is added to the suspension of sensitized staphylococci, agglutination occurs.     

Cerebral perfusion of metabolic inactivators: A new method for rapid fixation of labile lipid pools in brain

This paper describes a new method for the rapid fixation of labile lipid pools in the brain. Perfusion of the brain with 0.9% saline containing esterase inhibitors (p-bromphenacyl-bromide and diisopropyl fluorophosphate), an antioxidant (nordihydroguaiaretic acid) and a Ca²⁺ chelator (EDTA) resulted in a substantial reduction in the levels of free fatty acids, a biochemical marker for the degradation of labile membrane lipids. Levels of unesterified polyunsaturated fatty acids in whole brain were decreased by 90–96% as compared to levels in brains perfused with saline alone. Levels of docosahexaenoic acid approximated levels obtained after microwave irradiation. Unlike microwave irradiation, this perfusion technique perserves the cellular structure of the brain, thereby allowing subcellular fractionation with minimal postmortem changes in lipid pools. The release of arachidonic acid during isolation of the P₂ (synaptosomal) fraction was completely inhibited by the presence of the metabolic inactivators. The results of this study demonstrate a new and useful technique for the postmortem inactivation of enzymes responsible for the degradation of labile lipids in the brain. Further, the data underscore the key role of phospholipase A₂ and Ca²⁺ in mediating the release and accumulation of free fatty acids in the ischemic brain.Abbreviations 204 arachidonic acid - 226 docosahexaenoic acid - 160 palmitic acid - 180 stearic acid - 181 oleic acid - 182 linoleic acid - NDGA nordihydroguaiaretic acid - pBPB p-bromphenacylbromide - EDTA ethylenediamine-tetraacetic acid - DFP diisopropyl fluorophosphate - FFA free fatty acids - TLC thin layer chromatography - GLC gas liquid chromatography     

利用色谱法快速检测分析啤酒腐败菌的新方法

啤酒在生产过程中很容易染菌,而传统的用于啤酒腐败菌检测的方法耗时长,不能满足实际需求.由于腐败菌污染的啤酒通过色谱检测,相应组分(生物胺、有机酸和风味物质)都会有特征峰的产生,所以本研究通过建立无腐败菌污染的啤酒中各组分的标准色谱图,再使啤酒强制染菌,对其组分进行色谱分析,并与标准色谱图进行比较,从而找出各组分对应的特征峰.未来,此方法可用于实际生产线上快速检测啤酒是否发生微生物污染.     

A new rapid fluorogenic method for measuring bacteriocin activity

We describe a novel bacteriocin screening assay based on fluorescence emitted by berberine following its influx into compromised cells. This technique showed agreement with the conventional well-diffusion method, and results can be obtained within one hour. This assay could facilitate the rapid identification of bacteriocinogenic bacterial isolates.     

A new, rapid, method for preparation of dispersed pancreatic acini.

A new method for the preparation of pancreatic acini is described. The method is simple and much more rapid than previously described techniques, the time required for preparation of pancreatic acini being 20 min from removal of the pancreas. Acini prepared with this method perform in a superior manner when stimulated by either caerulein or secretin. Thus this new technique would be ideal for use in binding and secretion studies.     

A new, convenient method for the rapid analysis of inorganic pyrophosphate.

A new method for the rapid analysis of inorganic pyrophosphate (PP_i) which utilizes the enzyme ATP sulfurylase is described. All components of the assay system are commercially available and inexpensive. The assay is linear over the range of 0.5–50.0 nmol of PP_i and is not affected by inorganic phosphate. ATP and PP_i can both be analyzed using this method.     

A new method for the rapid separation of cell organelles

A rapid procedure is described for the separation of plant cell organelles from castor bean endosperm (Ricinus communis). This method is based on the reorientation of sucrose density gradients during centrifugation in a vertical rotor, thus resulting in a shorter path length and drastically reduced run times. Comparison to a separation by a standard procedure shows that, by using this method, equal resolution is possible in less than 10% spin time.     

A new rapid method for selective extraction of RNA from fixed mammalian tissues.

Treatment of formalin-fixed mammalian tissues with concentrated or 50% phosphoric acid at 5 degrees C for 20 and 50 min. respectively reveals complete extraction of RNA as judged by methyl green followed by staining with pyronin. This procedure also causes depolymerisation of DNA as indicated by the red staining of the nuclei. Sections treated with concentrated phosphoric acid at 5 degrees C for 30 min. causes disruption of the double helical structure of DNA what results in the depression of the pyronin staining. Similarly treated sections show Feulgen positive nuclei. Treatment of sections in 25 % phosphoric acid at 60 degrees C for 15 min. followed by staining with methyl green and pyronin show red nuclei, nucleoli and the cytoplasm. This indicates that extraction of RNA is only possible in cold and not at elevated temperature.     

A new method for rapid assignment of S-S bridges in proteins

A new method for complementing existing protein chemical techniques for the assignment of S-S bridge positions in amino-acid sequences is described. The principle of the method is the direct examination of the masses of protein fragments, obtained by chemical or enzymatic degradation. Proteins are digested under conditions known to minimise disulphide reduction and reshuffling, and the unfractionated digest is examined directly by high field magnet (or other high mass) fast atom bombardment or Californium mass spectrometry. Disulphide linked peptides are identified from their unique masses, and by comparison with the spectrum of digested and reduced samples in which the signal corresponding to the S-S linked peptide(s) is replaced by two signals corresponding to the respective thiol peptide components, if INTER-bridged, or shifted by two mass units (dithiol) if INTRA-bridged. This rapid procedure has considerable potential in assisting with studies on the primary structure of proteins, in crystallographic studies and the monitoring of denaturation/renaturation of recombinant proteins.     

一种快速鉴定转基因植物纯合体的新方法

植物转化中鉴定转基因植物的整合性是一个很重要的步骤,常规方法是对独立分离的转基因T1代植株产生的T2代进行转基因分离比率研究,以检测T1代的转基因整合状态,不仅费时费力,而且浪费了T1代资源。本介绍一种应用双重定量实时PCR技术鉴定转基因植物纯合子的新方法：以T1代植物DNA为模板,根据转基因后代的Ct表型值鉴定其转基因整合状态,Ct值接近2的为转基因纯合型,Ct值接近1的为转基因杂合型。用这种方法,可以同时对数十个T1代转基因幼苗的整合状态进行快速鉴定,准确率为100％。     

A new method for the rapid identification of genes encoding restriction and modification enzymes.

We have constructed derivatives of Escherichia coli that can be used for the rapid identification of recombinant plasmids encoding DNA restriction enzymes and methyltransferases. The induction of the DNA-damage inducible SOS response by the Mcr and Mrr systems, in the presence of methylated DNA, is used to select plasmids encoding DNA methyltransferases. The strains of E. coli that we have constructed are temperature-sensitive for the Mcr and Mrr systems and have been further modified to include a lacZ gene fused to the damage-inducible dinD locus of E. coli. The detection of recombinant plasmids encoding DNA methyltransferases and restriction enzymes is a simple, one step procedure that is based on the induction at the restrictive temperature of the lacZ gene. Transformants encoding DNA methyltransferase genes are detected on LB agar plates supplemented with X-gal as blue colonies. Using this method, we have cloned a variety of DNA methyltransferase genes from diverse species such as Neisseria, Haemophilus, Treponema, Pseudomonas, Xanthomonas and Saccharopolyspora.     

A new method in growth-electrophysiology: Pressurized intra-organ perfusion

Abstract A new experimental system was devised for the simultaneous measurement of elongation rate and the activity of the spatially separate electrogenic ion pumps of a hypocotyl segment excised from a seedling of Vigna unguiculata L. Walp. under enforced intra-organ perfusion by artificial solutions. The pathway of the perfusion medium was apoplastic space, including xylem vessels as main routes. The elongation rate of the segment was highly dependent on the perfusion pressure applied. It was possible to increase the growth rate under pressurized perfusion by 10-30 times as much as that without perfusion. Elongation rate was also dependent on respiration under perfusion, being retarded reversibly by anoxia a few minutes after the activities of the electrogenic ion pumps were stopped. Perfusion pressure had a little influence on the membrane potential (V_px) below a breakdown level (c. 130 kPa). Perfusion of mannitol or sorbitol solution of appropriate concentration reduced the elongation rate reversibly.     

Context-free spheres: A new method for rapid CPK image generation

A new algorithm for rendering CPK images of molecules is presented. The algorithm is based on the observation that (given certain assumptions) the appearance of a sphere representing an atom is independent of the atom's position or orientation. For example, the size of a sphere's projection on the viewing plane is independent of its distance from the viewing plane. The shading of a sphere is dependent only on lighting parameters that are identical for each atom type. This algorithm takes advantage of this observation by precomputing a template for each unique atom type and stamping these into the image with appropriate offsets in X, Y and Z. The implementation described herein enables generation of CPK images an order of magnitude faster than previous methods, with little sacrifice in image quality.     

Detection of the low-density-lipoprotein receptor with biotin-low-density lipoprotein. A rapid new method for ligand blotting.

A new technique has been developed to identify low-density-lipoprotein (LDL) receptors on nitrocellulose membranes, after transfer from SDS/polyacrylamide gels, by ligand blotting with biotin-modified LDL. Modification with biotin hydrazide of periodate-oxidized lipoprotein sugar residues does not affect the ability of the lipoprotein to bind to the LDL receptor. Bound lipoprotein is detected with high sensitivity by a streptavidin-biotin-peroxidase complex, and thus this method eliminates the need for specific antibodies directed against the ligand. The density of the bands obtained is proportional to the amount of pure LDL receptor protein applied to the SDS/polyacrylamide gel, so that it is possible to quantify LDL receptor protein in cell extracts. Biotin can be attached to other lipoproteins, for example very-low-density lipoproteins with beta-mobility, and thus the method will be useful in the identification and isolation of other lipoprotein receptors.     

A new internal perfusion method for transport studies in squid giant axons

A new internal perfusion method has been developed which allows control of the internal solute composition in squid axons. The superiority of this technique compared to the old perfusion methods is shown by the experiments performed which have reproduced, both qualitatively and quantitatively, the Na+ and Ca2+ fluxes observed in intact and dialyzed axons. Compared with the internal dialysis, the perfusion method has the advantage that the permeability barrier give by the porous capillary has been eliminated. This allows the introduction into the axon of solutes with very high molecular weight, at the same time that a fast and reliable internal control can be achieved.     

A new internal perfusion method for transport studies in squid giant axons

A new internal perfusion method has been developed which allows control of the internal solute composition in squid axons. The superiority of this technique compared to the old perfusion methods is shown by the experiments performed which have reproduced, both qualitatively and quantitatively, the Na⁺ and Ca²⁺ fluxes observed in intact and dialyzed axons. Compared with the internal dialysis, the perfusion method has the advantage that the permeability barrier given by the porous capillary has been eliminated. This allows the introduction into the axon of solutes with very high molecular weight, at the same time that a fast and reliable internal control can be achieved.