Electrophoresis of honey: characterization of trace proteins from a complex biological matrix by silver staining

The proteins of unconcentrated honey have been detected with the methylamine-incorporating silver stain (T. Marshall, 1984, Anal. Biochem. 136, 340-346) following sodium dodecyl sulfate-polyacrylamide gel electrophoresis or high-resolution two-dimensional electrophoresis. The former consistently reveals at least 19 protein bands in a variety of Australian honeys. Two-dimensional electrophoresis gave patterns of poor resolution but proved useful for further characterization of the major protein constituents. The protein patterns were unaffected by centrifugation of the samples prior to preparation for electrophoresis.

Simplified sodium dodecyl sulfate-polyacrylamide gel electrophoresis of unconcentrated urine with enhanced resolution and detection sensitivity

We applied a simple sodium dodecyl sulfate-polyacrylamide gel electrophoresis method to urine. The method, developed for serum protein analysis (Clin Chem 1984;30:475-9), has a high sample throughput and gives excellent resolution with unconcentrated urine. It clearly distinguishes and characterizes proteinuric urine (7.5 microL) by Coomassie Blue staining and gives complex silver-stained patterns with nonproteinuric urine (2 microL). The former is recommended for routine clinical screening, the latter for research purposes.

Simplified sodium dodecyl sulfate-polyacrylamide gel electrophoresis of unconcentrated urine with enhanced resolution and detection sensitivity

We applied a simple sodium dodecyl sulfate-polyacrylamide gel electrophoresis method to urine. The method, developed for serum protein analysis (Clin Chem 1984;30:475-9), has a high sample throughput and gives excellent resolution with unconcentrated urine. It clearly distinguishes and characterizes proteinuric urine (7.5 microL) by Coomassie Blue staining and gives complex silver-stained patterns with nonproteinuric urine (2 microL). The former is recommended for routine clinical screening, the latter for research purposes.

Stability of serum alanine aminotransferase activity

In this study the authors examine the effects of common storage and handling procedures on serum alanine aminotransferase (ALT) levels. Clotted blood samples from 14 subjects were centrifuged at 280 X g for 10 minutes. Serum was tested immediately for baseline ALT levels and aliquots were stored at 22, 4, -20, and -80 degrees C. Additional serums were stored on the clot at 22 and 4 degrees C. ALT quantitation was performed at intervals of 3, 6, 9, and 24 hours and on Days 2, 4, 6, and 8. Unseparated tubes were sampled both proximal and distal to the red cells to determine ALT leakage from red cells lysis. For all storage conditions, gradual loss of activity occurred over time. Mean activity loss in separated serum at 2 days was 6 percent at 4 degrees C and 20 percent at 22 degrees C. Mean loss in unseparated serum was 3 percent at 4 degrees C and 12 percent at 22 degrees C. Marked ALT loss averaging 46 percent by day 6 occurred with storage at -20 degrees C, whereas storage at -80 degrees C resulted in an 8 percent decrease for the same period. For storage of up to 1 week, it is recommended that serum be separated early and retained at 4 degrees C. Frozen samples should be kept at -80 degrees C. Storage of separated or unseparated blood for up to 24 hours at 22 or 4 degrees C, as commonly found in blood centers, will marginally adversely affect the accuracy of ALT determination.

Comparison of Coomassie Brilliant Blue protein dye-binding assays for determination of urinary protein concentration

We investigated the influence of assay protocol upon results of Coomassie Brilliant Blue protein dye-binding assays for urinary protein. Sensitivity and working range for, and linearity of response (including dilution dependence) of, three standard assays and four micro assays to bovine albumin, gamma-globulin, and urine are compared. The Read and Northcote standard assay (Anal Biochem 1981; 116:53-64) appears to be the method of choice.

Comparison of Coomassie Brilliant Blue protein dye-binding assays for determination of urinary protein concentration

We investigated the influence of assay protocol upon results of Coomassie Brilliant Blue protein dye-binding assays for urinary protein. Sensitivity and working range for, and linearity of response (including dilution dependence) of, three standard assays and four micro assays to bovine albumin, gamma-globulin, and urine are compared. The Read and Northcote standard assay (Anal Biochem 1981; 116:53-64) appears to be the method of choice.

Low incidence of acquired cytomegalovirus infection in neonates transfused with washed red blood cells

To define the incidence of cytomegalovirus (CMV) infection in infants given transfusions of washed blood cells from random donors, 100 infants who were identified as being CMV seronegative at birth were resampled at hospital discharge and again six weeks after hospitalization. All infants received washed red blood cell products; 37 infants received nonleukodepleted platelets and/or plasma. There were 7.4 donor exposures per infant. Donor units were assayed for anti-CMV IgG and IgM at the time of donation. Seventy-six infants received at least one transfusion from a seropositive donor (mean transfusion volume, 89 mL; mean, 3.7 seropositive donor exposures). Infection was defined by seroconversion to anti-CMV. None of the recipients of exclusively seronegative blood seroconverted. A single infant who received 34 mL of washed cells from a seropositive donor (IgG+, IgM-) and 31 mL of washed cells from a seronegative donor showed IgM anti-CMV 15 days after transfusion and IgG anti-CMV at a six-week follow-up visit. No recipients of IgM+ blood were infected. Our data demonstrate a 1.3% incidence of anti-CMV seroconversion following receipt of washed red cells from seropositive donors. This rate is within background levels for hospitalized neonates and is significantly lower than results of similar studies using unwashed blood.

A simplified method for the electrophoretic analysis of hair proteins

Hair proteins have been analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis using a simplified method without S-carboxymethylation, protein fractionation and lyophilization. The molecular weights of the proteins have been determined and human, rat, guinea pig, rabbit, gerbil, cow and sheep hair compared. These molecular weight values are consistent with those obtained using physical methods as compared to anomalously high values previously reported following electrophoresis of S-carboxymethylated hair proteins. Additional high molecular weight proteins, possibly of a dimeric nature, have also been detected.

Characterization and quantitation of membrane antigens of New World Leishmania species by using monoclonal antibodies in Western blot and flow microfluorometric assays

Membrane-specific monoclonal antibodies generated against promastigotes of New World Leishmania species were used in Western blot, ELISA, and flow microfluorometric assays to characterize their antigen specificity and to determine the external surface distribution of the reactive epitopes. Three major membrane antigens of molecular weight 72 KD, 55 KD, and 42 KD were identified as well as a dominant antigen that migrated as a broad band on SDS-PAGE, corresponding to a molecular weight of 10-15 KD. By dot-ELISA this antigen was also found to be excreted by promastigotes into their culture medium. One minor membrane antigen of 25 KD and a triplet component of 66, 58, and 56 KD were also identified. While assays performed on air-dried promastigotes revealed the almost ubiquitous presence of the 72 KD and 55 KD antigens, indirect immunofluorescent staining of live promastigotes followed by flow cytometric analysis revealed that these antigens had no external exposure. Antibodies binding the 55 KD component were also reactive toward purified mammalian tubulin. The remaining antigens had a variable distribution on the eight isolates utilized, and these quantitative differences could be used to distinguish isolates of the Leishmania mexicana complex from those belonging to the Leishmania braziliensis complex.

Phenol addition to the Bradford dye binding assay improves sensitivity and gives a characteristic response with different proteins

Phenol has been added to the Coomassie Brilliant Blue G-250 dye reagent used in the standard Bradford protein assay and its effect upon the reagent blank and assay response of fourteen proteins investigated. Phenol can enhance or impair colour yield depending upon its concentration and the amount and type of protein assayed. Four characteristic protein responses to increasing assay concentrations of phenol have been observed. These indicate a complex influence of phenol upon the protein assay. Dye reagent containing 0.5% phenol gave optimal colour yield with most of the proteins investigated and an improved assay response of ovalbumin, ribonuclease, lysozyme, insulin, pepsin and chymotrypsinogen-A relative to bovine albumin.

Flow cytometric analysis of the effects exerted by monoclonal antibodies on binding and uptake of Leishmania mexicana subsp. mexicana promastigotes by murine peritoneal macrophages

A flow cytometric assay was developed to quantitate the binding kinetics of Leishmania mexicana subsp. mexicana promastigotes to murine peritoneal macrophages and to determine if selected membrane-specific monoclonal antibodies would exert an effect on the binding process. A total of three monoclonal antibodies, all reactive with a similar 42-kilodalton surface membrane component by Western blot analysis, enhanced parasite-macrophage binding at levels greater than 45%. An additional three monoclonal antibodies that identified low-molecular-weight antigens of the promastigote (15 to 20 kilodaltons) had no effect on the binding process. Of these antibodies, however, one did appear to inhibit the internalization of the parasites after it attached to the macrophage membrane.

Identification and recovery of Leishmania antigen displayed on the surface membrane of mouse peritoneal macrophages infected in vitro

A murine monoclonal antibody (83L-2D3/a) to a dominant surface antigen of Leishmania braziliensis panamensis (WRAIR-470) recognized a determinant expressed on the surface membrane of mouse peritoneal macrophages infected in vitro. This determinant, also demonstrable on the surface membrane of intracellular amastigotes, was not displayed by the macrophage until at least 6 hr post-infection. This delay in expression and the obvious negativity of all uninfected macrophages inherent to infected cultures implied that the leishmania determinant had an intracellular origin. Furthermore, expression was dependent upon maintenance of macrophage function. When the parasite burden became overwhelming, additional antigen processing ceased, and that which had accumulated was either shed into the medium or was internalized. Immunochemical analyses revealed that the 83L-2D3/a reactive epitope was part of a 15,000 dalton molecule, which in all likelihood represents a breakdown product of a major surface glycoconjugate that had been degraded in the phagolysosome.

Identification and recovery of Leishmania antigen displayed on the surface membrane of mouse peritoneal macrophages infected in vitro

A murine monoclonal antibody (83L-2D3/a) to a dominant surface antigen of Leishmania braziliensis panamensis (WRAIR-470) recognized a determinant expressed on the surface membrane of mouse peritoneal macrophages infected in vitro. This determinant, also demonstrable on the surface membrane of intracellular amastigotes, was not displayed by the macrophage until at least 6 hr post-infection. This delay in expression and the obvious negativity of all uninfected macrophages inherent to infected cultures implied that the leishmania determinant had an intracellular origin. Furthermore, expression was dependent upon maintenance of macrophage function. When the parasite burden became overwhelming, additional antigen processing ceased, and that which had accumulated was either shed into the medium or was internalized. Immunochemical analyses revealed that the 83L-2D3/a reactive epitope was part of a 15,000 dalton molecule, which in all likelihood represents a breakdown product of a major surface glycoconjugate that had been degraded in the phagolysosome.

Plasma apolipoprotein pattern in fish-eye disease examined by high-resolution two-dimensional electrophoresis

We compared the plasma protein patterns of the two living patients suffering from fish-eye disease with those of appropriate controls, using high-resolution two-dimensional electrophoresis. Quantitative abnormalities were detected in plasma polypeptides corresponding to the isoforms of apolipoproteins A-I and A-II. The disease was characterized by normal concentrations of proapo A-I but dramatically subnormal concentrations of the other apo A-I isoforms and apo A-II. No significant difference was detected in the concentrations of other plasma proteins. These findings are discussed in relation to other apolipoprotein disorders.

Plasma apolipoprotein pattern in fish-eye disease examined by high-resolution two-dimensional electrophoresis

We compared the plasma protein patterns of the two living patients suffering from fish-eye disease with those of appropriate controls, using high-resolution two-dimensional electrophoresis. Quantitative abnormalities were detected in plasma polypeptides corresponding to the isoforms of apolipoproteins A-I and A-II. The disease was characterized by normal concentrations of proapo A-I but dramatically subnormal concentrations of the other apo A-I isoforms and apo A-II. No significant difference was detected in the concentrations of other plasma proteins. These findings are discussed in relation to other apolipoprotein disorders.

Subcellular and taxonomic specificity of monoclonal antibodies to New World Leishmania

Murine monoclonal antibodies to flagellar, surface membrane and cytoplasmic antigens of New World Leishmania were assessed for their taxonomic specificity in enzyme-linked immunosorbent assays with three genera of the family Trypanosomatidae and three species and seven subspecies of the genus Leishmania. Antibodies exhibiting exclusive reactivity with either the flagellum, flagellar pocket, kinetoplast, or nucleus lacked specificity at all phylogenetic levels and, in fact, recognized epitopes common to cultured mammalian cells. Monoclonals to intracellular antigens were capable of distinguishing Leishmania from Trypanosoma and Endotrypanum. Antibodies reactive at the surface membrane could separate six isolates of L. braziliensis from three isolates of L. mexicana but the differences in antigen expression were frequently quantitative rather than qualitative. Antigenic variability within species and/or subspecies often exceeded that which was observed between species and/or subspecies. At least one monoclonal antibody was specific for a surface antigen peculiar to a subpopulation of promastigotes of an L. braziliensis panamensis isolate.