Separation and some properties of the major proteins of the human erythrocyte membrane

A fractionation procedure is described which allows the isolation of three major human erythrocyte membrane proteins. Their isolation involves three sequential extraction procedures followed by gel filtration in 1% sodium dodecyl sulphate and preparative gel electrophoresis. All three proteins can be isolated from a single preparation. One of the proteins is the erythrocyte sialoglycoprotein, for which no C- or N-terminal residues were found. The other two proteins, which have not previously been isolated, have subunit molecular weights of 74000 and 93000 and contain 9 and 7% carbohydrate respectively. These glycoproteins have blocked N-terminal residues and show similarities in their chemical properties. Preparations derived from blood-group O erythrocytes contain no N-acetylgalactosamine, but similar preparations from blood-group A erythrocytes do contain this sugar. These three proteins cannot easily be solubilized by gentle aqueous procedures and represent about half of the erythrocyte ;ghost' protein. They carry a large proportion of the cell-surface carbohydrate.     

Fish gonadotropin(s). II. Isolation of gonadotropin(s) from chum salmon pituitary glands using affinity chromatography.

A highly purified gonadotropic hormone preparation has been obtained from chum salmon (Oncorhynchus keta) pituitaries by extraction with ethanolic or aqueous buffer, affinity chromatography on Con A Sepharose and gel filtration on Sephadex G-75 superfine. A purified fraction from Sephadex G-75 averaged 448 mug NIH-LH-S18/mg glycoprotein as measured by the uptake of radiophosphate into chick testes. A total of 1.1 g of salmon gonadotropin (s) (SG)/kg fresh tissue was recovered when the isolation began with an aqueous extraction. Analytical polyacrylamide gel electrophoresis (P.A.G.E.) of the purified fraction from Sephadex G-75 displayed a single broad zone in non-dissociating conditions and two bands in 8 M urea. Polyacrylamide gel electrofocusing yielded six sharp bands with an isoelectric point range of 4.38 to 5.05, and four bands with an isoelectric point range of 4.31 to 4.95 in 8 M urea. A molecular weight of 41,000 was determined by gel filtration. A subunit molecular weight of 17,800 +/- 10% was found by P.A.G.E. in 0.1% sodium dodecyl sulphate (SDS), suggesting that native SG consists of two subunits. Purified preparations were highly stable in Tris-Cl buffers and retained their activity for several months when stored at -73 degrees C.     

Carcinoscorpius rotunda cauda amoebocyte lysate for detection of endotoxins--its preparation, stability, sensitivity and comparison with Limulus amoebocyte lysate

Carcinoscorpius amoebocyte lysate (CAL) was prepared from C. rotunda cauda by a modification of the method described by Mahalanabis et al. [Indian J Med Res, 70 (1979) 35]. Seasonal variation as well as batch variation was observed in the yield of haemolymph and the total lysate protein. In the presence of E. coli lipopolysaccharide (pure, free endotoxin) and E. coli and Salmonella cell suspensions (bound endotoxin), the CAL formed a gel after incubation at 37 degrees C. The gelling time varied from 10-90 min depending on the concentration of endotoxin used; higher concentrations formed gel more rapidly. The endotoxin detection capacity (sensitivity) of the lysate preparations was influenced by the season in which prepared, but not by the total protein content. Ten fold increase in the sensitivity was achieved by a purification step using chloroform. Although subsequent frozen storage with or without lyophilization did not alter the initial sensitivity, it was either decreased considerably or lost totally when the lysate was stored for 4 months at 4 degrees C or for 2 months at 30 degrees C. Under the same conditions, Limulus lysate was more stable. The lost sensitivity could not be regained by the incorporation of divalent cations (Ca2+ and Mg2+). The CAL preparations in general were able to detect as little as 10-100 pg of endotoxin or as few as 10(3) cells of E. coli or 10(4) cells of Salmonella and were comparable to LAL. CAL could be used successfully in lieu of Limulus amoebocyte lysate in the detection and assay of endotoxins.     

Low endotoxic activity of lipopolysaccharides isolated from Bradyrhizobium, Mesorhizobium, and Azospirillum strains

The endotoxic activities of lipopolysaccharides (LPS) isolated from different strains of rhizobia and rhizobacteria (Bradyrhizobium, Mesorhizobium, and Azospirillum) were compared to those of Salmonella enterica sv. Typhimurium LPS. The biological activity of all the examined preparations, measured as Limulus lysate gelation, production of tumor necrosis factor (TNF), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and nitrogen oxide (NO) induction in human myelomonocytic cells (line THP-1), was considerably lower than that of the reference enterobacterial endotoxin. Among the rhizobial lipopolysaccharides, the activities of Mesorhizobium huakuii and Azospirillum lipoferum LPSs were higher than those of the LPS preparations from five strains of Bradyrhizobium. The weak endotoxic activity of the examined preparations was correlated with differences in lipid A structure compared to Salmonella.     

介绍一种简单高效的植物总RNA提取方法

在液氮中研磨小麦幼叶和不同发育时期的种子,经含0.1% SDS和0.1%十二烷基肌氨酸钠(LDS)的尿素缓冲液裂解后,醋酸钠和氯仿沉淀变性蛋白质,异丙醇沉淀核酸,溶解后经2.5mol/L LiCl沉淀总RNA,洗涤后就可得到高质量的总RNA,其OD260/OD280 为2.05~2.10,28S和18S RNA带清晰,叶片总RNA还可得到23S和16S RNA带,产率可达5mg RNA/10g材料。当使用含1% SDS和1% LDS的尿素缓冲液裂解材料时,则可用于DNA的分离提取,其分子大小可达50~100kb以上。 Abstract:Wheat leaf and seeds at different development stages had been squashed in liquid nitrogen,then lysised by urea buffer which contains 0.1% SDS and 0.1% LDS,denatured protein had been removed by NaAc and chloroform precipitation,total RNA was further purified by LiCl.The RNA we obtained had sharp bands of 28S and 18S after agarose gel electrophoresis,23S and 16S RNA bands can also be seen clearly in leaf RNA extract,the value of OD260/OD280 of RNA was 205~210.5mg RNA can been isolated from 10g leaf of wheat.This method can also been used in high molecular weight DNA isolation but the concentration of SDS and LDS must be increased to 1%.     

Source and avoidance of the "nothing dehydrogenase" effect, a spurious band produced during polyacrylamide gel electrophoresis of dehydrogenase enzymes from yeasts

During a study of the distribution of several NAD-linked dehydrogenase enzymes in various yeasts, in which polyacrylamide gel electrophoresis, followed by activity staining with phenazine methosulfate and a tetrazolium was used, a band was frequently detected, the production of which appeared to be independent of any added substrate (the "nothing dehydrogenase" effect). It has been shown that this effect is caused by alcohol dehydrogenase acting on traces of ethanol inadvertently introduced into the system. Two sources of ethanol were identified. They were (i) the enzyme extracts, which could be freed from ethanol by gel filtration, and (ii) the acrylamide used to prepare the gel, which could be freed from ethanol by recrystallization from ethanol-free chloroform. It is suggested that the use of commercial chloroform (stabilized with ethanol) as a recrystallizing solvent is the source of ethanol contamination in commercial preparations of acrylamide.     

一种适用范围广的总RNA提取方法

介绍一种RNA提取方法,该方法以SDS、氯仿和Tris苯酚为主要提取试剂,以LiCl和乙醇为RNA沉淀试剂。分别以柽柳(木本植物)、星星草(草本植物)、天牛（昆虫）、酿酒酵母和白腐菌（真菌）为RNA提取材料,用该方法成功地提取出了它们的总RNA。获得的RNA条带清晰,A₂₆₀/A₂₈₀ 在1.8以上。通过对LiCl和乙醇沉淀RNA的效果分析表明,该方法可在10 min内完全沉淀RNA,同时也可以同时获得纯度较高的DNA。提取的RNA质量可满足cDNA文库构建,基因芯片探针标定和RT-PCR等对RNA质量要求较高的分子生物学操作,说明这是一种应用范围广的RNA提取方法。     

Affinity chromatography of H+-translocating adenosine triphosphatase isolated by chloroform extraction of Rhodospirillum rubrum chromatophores. Modification of binding affinity by divalent cations and activating anions.

1. ATPase isolated from Rhodospirillum rubrum by chloroform extraction and purified by gel filtration or affinity chromatography shows three bands (alpha, beta and gamma) upon electrophoresis in sodium dodecyl sulphate. 2. Ca2+-ATPase activity of the preparation is inhibited by aurovertin and efrapeptin but not by oligomycin. Activity may be inhibited by treatment with 4-chloro-7-nitrobenzofurazan and subsequently restored by dithiothreitol. 3. The enzyme fails to reconstitute photophosphorylation in chromatophores depleted of ATPase by sonic irradiation. 4. Most of the active protein from the crude chloroform extract binds to an affinity chromatography column bearing an immobilised ADP analogue but not to a column bearing immobilised pyrophosphate. 5. In the absence of divalent cations, a component with a very high specific activity for Ca2+-ATPase is eluted from the column by 1.6 mM ATP. This protein migrates asa single band on 5% polyacrylamide gel electrophoresis and only possesses three subunits. At 12 mM ATP an inactive protein is eluted which does not run on acid or alkali polyacrylamide gels and shows a complex subunit structure. 6. ATPase preparations prepared by acetone extraction or by sonic irradiation of chromatophores may also be purified 10-fold by affinity chromatography. 7. The inclusion of 5 mM MgCl2 or CaCl2 during affinity chromatography of chloroform ATPase increases the capacity of the column for the enzyme and demands a higher eluting concentration of ATP. 8. When the enzyme is more than 90% inhibited by efrapeptin or 4-chloro-7-nitrobenzofurazan, the binding characteristics of the enzyme are not affected. 9. 10 mM Na2SO3, which greatly stimulates the Ca2+- and Mg2+-dependent ATPase activity of the enzyme and increases Ki (ADP) for Ca2+-ATPase from 50 to 850 micron, prevents binding to the affinity column. Binding may be restored by the addition of divalent cations. 10. Na2SO3 increases the rate of ATP hydrolysis, ATP-driven H+ translocation and ATP-driven transhydrogenase in chromatophores. 11. It is proposed that anions such as sulphite convert the chromatophore ATPase into a form which is a more efficient energy transducer.     

Isolation of protein components from rat lung lamellar bodies

Lamellar bodies isolated from 10% (w/v) rat lung homogenates by discontinuous sucrose gradient centrifugation were shown to contain variable amounts of adhering proteins. These contaminating proteins could be removed by either Sepharose 4B gel filtration or precipitation of the crude preparation at pH 11.5. Both purification methods yielded membrane preparations with a phospholipid-to-protein ratio of 10.0 μmol/mg. Nearly complete separation of lamellar body phospholipid and protein could be achieved upon application of the purified membranes to DEAE-cellulose in the presence of 0.2% (v/v) Triton X-100. Phospholipid analyses showed that 83% of total lipid phosphorus was recovered in phosphatidylcholine. In phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine and phosphatidylinositol recoveries amounted to 4, 8, 2 and 2%, respectively. Molecular mass determinations of the isolated protein component of lamellar bodies by means of SDS polyacrylamide gel electrophoresis and staining with Coomassie brilliant blue revealed the presence of three protein bands with molecular masses of 64, 33 and 31 kDa. Upon staining with silver a 16 kDa protein was also visible. Sephadex G-100 gel filtration showed only one protein peak corresponding to a molecular mass of 64 kDa when protein was assayed with Coomassie brilliant blue.     

Protein-carbohydrate-lipid complex isolated from the cell envelopes of Chlamydia psittaci in alkaline buffer and ethylenediaminetetraacetate.

Exposure of isolated cell envelopes from purified infectious elementary (EB) of Chlamydia psittaci to sodium carbonate-bicarbonate buffer at pH 10 plus ethylenediaminetetraacetate (EDTA) results in partial solubilization of the total protein. The released materials represent 20% of the dry weight, 16% of the total protein, 40% of the total carbohydrate, and 9% of the total lipid of the cell envelopes. Sucrose density gradient centrifugation, and Sephadex G-200, Sepharose 4B, or diethylaminoethyl-cellulose column chromatography, reveal a protein-carbohydrate-lipid complex of several hundred thousand molecular weight that contains 50% protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the isolated EB cell envelopes reveals two major protein bands, A and B, with estimated molecular masses of approximately 85,000 and 53,000, respectively, both of which also stain for the presence of carbohydrate and lipid. Gel electrophoresis of the protein-carbohydrate-lipid complex reveals two protein bands, C and D, with estimated molecular weights of approximately 17,000 and 13,000, respectively, which contain lipid and a small amount of carbohydrate; bands A and B are not present in the complex. Gel electrophoresis of the cell envelope residues after extraction of the complex with alkali and EDTA shows a single main band, corresponding to the position of band B, which contains protein, carbohydrate, and lipid; band A is completely missing. B and A is believed to be a component of the complex, which is split into two subunits on alkali solubilization.     

Solvent comparison in the isolation, solubilization, and toxicity of Stachybotrys chartarum spore trichothecene mycotoxins in an established in vitro luminescence protein translation inhibition assay

It is well known that non-viable mold contaminants such as macrocyclic trichothecene mycotoxins of Stachybotrys chartarum are highly toxinigenic to humans. However, the method of recovering native mycotoxin has been without consensus. Inconsistencies occur in the methods of isolation, suspension, preparation, and quantitation of the mycotoxin from the spores. The purpose of this study was to provide quantitatively comparative data on three concurrent preparations of 10(6)S. chartarum spores. The experiments were designed to specifically evaluate a novel method of mycotoxin extraction, solubilization, and the subsequent inhibitory effect in an established in vitro luminescence protein translation assay from 30 day-old spores. The mycotoxin-containing spores swabbed from wallboard cultures were milled with and without glass beads in 100% methanol, 95% ethanol, or water. Milled spore lysates were cleared of cell debris by filter centrifugation followed by a second centrifugation through a 5000 MWCO filter to remove interfering proteins and RNases. Cleared lysate was concentrated by centrivap and suspended in either alcohol or water as described. The suspensions were used immediately in the in vitro luminescence protein translation assay with the trichothecene, T-2 toxin, as a control. Although, mycotoxin is reported to be alcohol soluble, the level of translation inhibition was not reliably satisfactory for either the methanol or ethanol preparations. In fact, the methanol and ethanol control reactions were not significantly different than the alcohol prepared spore samples. In addition, we observed that increasing amounts of either alcohol inhibited the reaction in a dose dependent manner. This suggests that although alcohol isolation of mycotoxin is desirable in terms of time and labor, the presence of alcohol in the luminescence protein translation reaction was not acceptable. Conversely, water extraction of mycotoxin demonstrated a dose dependent response, and there was significant difference between the water controls and the water extracted mycotoxin reactions. In our hands, water was the best extraction agent for mycotoxin when using this specific luminescence protein translation assay kit.     

Method for reducing endotoxin in Moraxella catarrhalis UspA2 protein preparations

The UspA2 protein from the bacterium Moraxella catarrhalis is a potential vaccine candidate for preventing human diseases caused by this organism. Before a vaccine can be administered parentally, the level of endotoxin must be reduced as much as possible. However, in this case the endotoxin was very tightly complexed with the UspA2 protein and could not be dissociated with Triton X-100. It was found that it dissociated from the protein with the zwitterionic detergents Zwittergent 3-12 and Zwittergent 3-14. The endotoxin could then be separated from the protein by either ion-exchange or gel filtration chromatography. Using the limulus amoebocyte lysate assay for quantitation, the endotoxin was reduced approximately 20 000-fold. The removal of residual endotoxin from UspA2 preparations had no detrimental effect on the immunological properties of the protein. Mouse antisera raised against UspA2 prior to, and following endotoxin reduction exhibited comparable antibody and bactericidal titers against the tested strains. Further, mice immunized with both preparations, followed by pulmonary challenge with either a homologous or a heterologous isolate, exhibited comparable levels of clearance.     

Detection of an immunoglobulin-like serum protein possessing a high affinity for collagen

Fibronectin isolated from bovine serum by affinity chromatography on collagen-Sepharose was found to contain a great number of concomitant proteins. Polyacrylamide gel electrophoresis of experimental samples pretreated with beta-mercaptoethanol under denaturation conditions resulted in the polypeptide fractions with Mr of 25, 54 and 82 KD, while the non-treated samples contained only one protein of non-fibronectin type (Mr = = 180-190 KD). This protein was isolated from the total preparations of collagen-binding proteins by the procedures generally employed for the isolation of purified preparations of immunoglobulins G; this protein was also isolated from purified immunoglobulins G using affinity chromatography on collagen-Sepharose. In terms of its molecular weight, subunit composition and immunological and chromatographical behaviour this protein can be related to immunoglobulins. The immunoglobulin-like protein isolated together with fibronectin revealed an affinity for denatured collagen, but not for fibronectin or Sepharose. The content of immunoglobulin with an affinity for denatured collagen in the total fraction of immunoglobulins G is 0.3-0.5%.     

Rapid purification of proteolipids from rat brain subcellular fractions by chromatography on a lipophilic dextran gel

Proteolipids from adult rat brain subcellular fractions were purified by a one-step procedure involving chromatography through Sephadex LH-60 eluted with an acidified chloroform—methanol mixture.The protein peak was eluted with the void volume and was free of adventitious lipids. The degree of purification was similar to that attained with the neutral—acidified chloroform—methanol dialysis method with the advantage that this new procedure can be carried out in only 3 h, with a recovery of proteins of 95–100%. Samples containing different lipid/protein ratios passed through the gel gave similar elution profiles.When labeled amino acids or palmitic acid were added to myelin total lipid extracts, no radioactivity was eluted with the protein, indicating that the proteolipid apoproteins purified by this method do not adsorb hydrophobic low-molecular-weight compounds.     

Resolution of highly purified toxic-shock syndrome toxin 1 into two distinct proteins by isoelectric focusing

Highly purified toxic-shock syndrome toxin 1 (TSST-1) was prepared by differential precipitation with ethanol and resolubilization in water followed by successive electrofocusing in pH gradients of 3-10, 6-8, and 6.5-7.5. TSST-1, thus isolated, migrated as two distinct protein bands with isoelectric points of 7.08 (TSST-1a) and 7.22 (TSST-1b). When tested by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both toxins migrated as homogeneous bands with molecular weights of 22 000. The gel bands were visualized by silver staining. The two toxins have nearly identical amino acid compositions and are immunologically identical as shown by Ouchterlony reactivity against TSST-1 hyperimmune serum. TSST-1a and TSST-1b have the same biological activities as TSST-1: the capacity to induce fever, enhancement of host susceptibility to lethal endotoxin shock, nonspecific T lymphocyte mitogenicity, and suppression of immunoglobulin M synthesis against sheep erythrocytes. These two proteins have been isolated from several different TSS-associated Staphylococcus aureus strains. The data suggest that the differences in isoelectric point result either from the presence of a cofactor or from alternative conformations. Since only two bands appear, microheterogeneity as a result of deamination or acetylation is unlikely.     

Purification of peroxisomes from livers of normal and clofibrate-treated mice

A method for the isolation of peroxisomes from livers of normal and clofibrate-treated mice is described. The method utilizes glutaraldehyde to stabilize peroxisomal membranes, and isopycnic centrifugation of a light mitochondrial fraction through a linear metrizamide gradient to achieve optimal resolution from other organelles. On the basis of the biochemical and morphological data, the peroxisomal preparations are indicated as of high purity: contamination by mitochondria, lysosomes, and plasma membranes is negligible, and the level of contaminating microsomes is around 5% for normal peroxisomes and 8% for peroxisomes from clofibrate-treated mice. Peroxisomal membranes prepared by carbonate extraction contain two major polypeptides of approximately 70,000 Da, and show 2 and 8% contamination by microsomal membrane protein for the preparations from normal and clofibrate-treated mice, respectively.     

Preparation of the proteolipid apoprotein from bovine heart, liver and kidney.

Proteolipid apoproteins have been prepared from heart, kidney, and liver by dialysis in chloroform/methanol against chloroform/methanol, acidified chloroform/methanol, and chloroform/methanol in succession. They are free of lipids (less than 0.05% P; less than 0.1% carbohydrate). They show a high content of non-polar amino acids, methionine, and tryptophan and contain little or no half-cystine. The differ from neural proteolipid apoproteins by absence of half-cystine, and of covalently bound fatty acids. As recovered from chloroform/methanol solutions, they are soluble in chloroform/methanol and insoluble in water, but a water-soluble form can be prepared by changing the solvent from chloroform/methanol to water in a stream of nitrogen. The chloroform-methanol-soluble form and the water-soluble form are interconvertible. ORD and CD spectra of all proteolipid apoproteins indicate 60-70% alpha-helix content in chloroform/methanol solution and 20-30% alpha-helix in water solution. Sodium dodecyl sulfate gel electrophoresis resolves proteolipid apoprotein into two major components corresponding to ca. 12 000 and 34 000 daltons. With sodium dodecyl sulfate/urea numerous bands appear, with a major one at 30 000 daltons and 8 to 10, ranging downward to 2500. For comparison, neural proteolipid apoproteins also show numerous bands with a major one at 25 000. The marked chemical and physical similarities among all proteolipid apoproteins studied suggest a common role in membrane structures.     

An efficient and optimized purification procedure for the superoxide dismutase from Aspergillus niger. Partial characterization of the purified enzyme

Cu, Zn-superoxide dismutase was isolated from Aspergillus niger mycelia, harvested at the mid-logarithmic growth phase. The purification scheme aimed at the optimization of the ethanol/chloroform extraction (Tsuchihashi extraction) through response surface methodology. Upon optimum extraction conditions, it was possible to obtain electrophoretically pure enzyme preparations, by the application of one step anion exchange chromatography. The enzyme yield of this simple purification procedure was above 75% while the specific activity of the final preparation was among the highest reported for eucariotic microorganisms. The purified enzyme exhibited similar physicochemical characteristics with other Aspergillus sp. superoxide dismutases revealing an apparent tetrameric structure with a subunit molecular weight of 19 kDa, and a pl of 5.95.This revised version was published online in October 2005 with corrections to the Cover Date.     

Cutting edge: repurification of lipopolysaccharide eliminates signaling through both human and murine toll-like receptor 2

Toll-like receptor (TLR) 2 has recently been associated with cellular responses to numerous microbial products, including LPS and bacterial lipoproteins. However, many preparations of LPS contain low concentrations of highly bioactive contaminants described previously as "endotoxin protein," suggesting that these contaminants could be responsible for the TLR2-mediated signaling observed upon LPS stimulation. To test this hypothesis, commercial preparations of LPS were subjected to a modified phenol re-extraction protocol to eliminate endotoxin protein. While it did not influence the ability to stimulate cells from wild-type mice, repurification eliminated the ability of LPS to activate cells from C3H/HeJ (Lpsd) mice. Additionally, only cell lines transfected with human TLR4, but not human or murine TLR2, acquired responsiveness to both re-extracted LPS and to a protein-free, synthetic preparation of lipid A. These results suggest that neither human nor murine TLR2 plays a role in LPS signaling in the absence of contaminating endotoxin protein.