A comparison of two methods for assessing critical flicker fusion frequency in hens

This paper compared two general methods for assessing critical fusion frequency in hens (gallus gallus domesticus). The first method was a conditional discrimination procedure with the stimuli presented successively. The second was a two-alternative forced-choice procedure with the stimuli presented simultaneously. It was found that both methods of stimulus presentation gave comparable results suggesting that either method is useful when investigating psychophysics in animals. The results also show that hens’ critical fusion frequency is considerably higher than that of humans which may account for hens’ inability to recognise images presented on standard computer or television monitors.     

An examination of the rate assay to determine the active site normality of papain

Data are presented which demonstrate that the α-N-benzoyl-l-argine ethyl ester rate assay procedure, based on a burst titration with N-benzyloxy-carbonyl-l-tyrosine p-nitrophenyl ester as previously desribed (1), is an accurate and reliable method for determining the normality of papain in solution.     

Chromatography of Cytokinins on a Neutral Polystyrene Resin: A Simple Procedure for the Separation of the cis and trans Isomers of Zeatin or Ribosylzeatin

A simple procedure for the separation of the cis and trans isomers of zeatin and ribosylzeatin by column chromatography on a neutral polystyrene resin, Porapak Q, in aqueous ethanol solutions is reported. The method has been used to examine the stereoisomer composition of ribosylzeatin isolated from wheat germ transfer RNA. Chromatographic data for several other cytokinins are also presented.     

Rapid Mini-Prep Isolation of High-Quality Plasmid DNA from Lactococcus and Lactobacillus spp.

A simple, rapid plasmid mini-prep procedure for lactococci and lactobacilli which gives high yields and can be performed on overnight broth cultures is presented. Large plasmids were isolated from both lactococci and lactobacilli, including a 70-kb plasmid from Lactobacillus acidophilus C7. The purity of the resulting plasmid DNA makes it suitable for subsequent molecular manipulations. The convenience of the technique makes this rapid mini-prep procedure suitable for routine plasmid isolation from lactic acid bacteria.     

The negative staining-carbon film procedure: Technical considerations and a survey of macromolecular applications

The development and initial virological applications of the negative staining-carbon film (NS-CF) procedure are described and followed by a survey of some recent macromolecular applications of the technique. Electron microscopical data are shown which indicate the capability of the technique for the production of two-dimensional (2-D) crystals from several different soluble proteins (human erythrocyte catalase, human erythrocyte, Xenopus and Thermoplasma acidophilum cylindrin/multicatalytic proteinase, yeast glutamine synthetase and keyhole limpet haemocyanin). Instances in which ordered two-dimensional close-packing of molecules is produced, rather than true two-dimensional crystallization, are also indicated. In addition, data obtained from the application of the NS-CF procedure to a number of fibrillar proteins are briefly presented. Examples include bovine lens vimentin, thrombin-cleaved vimentin and bacterially expressed Xenopus lamin-A. These elongated proteins form higher order filamentous structures, networks and, in the case of lamin-A, large paracrystalline structures. A general discussion of the achievements and future potential of the NS-CF procedure is presented.     

Electrophoresis of acidic glycosaminoglycans in hydrochloric acid: a micro method for sulfate determination

A rapid and simple method for estimation of the sulfate content of less than 1 μg of acidic glycosaminoglycans is presented. The procedure is based on the fact that the electrophoretic mobility in 0.1 M hydrochloric acid is proportional to the sulfate content of the polysaccharide.     

Studies on growth regulators. I. Improved Avena coleoptile elongation test for auxin

A modified procedure is presented for the bioassay of auxin using Avena coleoptile segments. The modifications introduced result in a substantial improvement of the commonly used coleoptile elongation tests.     

State estimation of a Uricase production process with Candida Utilis

The present work discusses the implementation of a Kalman filtering procedure in a state estimation of a batch Uricase production process with Candida Utilis. An unstructured model of the process is used for the estimation procedure. The observability is thoroughly investigated and a Kalman filter is applied afterwards as a powerful and precise state estimation tool. The estimates in all cases of observability are presented, compared and discussed.     

Encapsulating Cytochrome c in Silica Aerogel Nanoarchitectures without Metal Nanoparticles while Retaining Gas-phase Bioactivity

Applications such as sensors, batteries, and fuel cells have been improved through the use of highly porous aerogels when functional compounds are encapsulated within the aerogels. However, few reports on encapsulating proteins within sol–gels that are processed to form aerogels exist. A procedure for encapsulating cytochrome c (cyt. c) in silica (SiO₂) sol-gels that are supercritically processed to form bioaerogels with gas-phase activity for nitric oxide (NO) is presented. Cyt. c is added to a mixed silica sol under controlled protein concentration and buffer strength conditions. The sol mixture is then gelled and the liquid filling the gel pores is replaced through a series of solvent exchanges with liquid carbon dioxide. The carbon dioxide is brought to its critical point and vented off to form dry aerogels with cyt. c encapsulated inside. These bioaerogels are characterized with UV-visible spectroscopy and circular dichroism spectroscopy and can be used to detect the presence of gas-phase nitric oxide. The success of this procedure depends on regulating the cyt. c concentration and the buffer concentration and does not require other components such as metal nanoparticles. It may be possible to encapsulate other proteins using a similar approach making this procedure important for potential future bioanalytical device development.     

A new simplified method for constructing Wagner networks and the cladistics of Pentachaeta (Compositae,Astereae)

The new procedure for constructing a Wagner network presented differs from Farris’s (1970) method in that the amount of computation required is reduced. The usefulness of this procedure was examined by applying it to the 20 characters considered in a recent monograph of the seven OTUs of the genusPentachaeta. A single network was derived from some 945 or more networks possible for this group. A comparison of the network constructed by this simplified method to that constructed by Farris’ procedure revealed no differences. An attempt to reconstruct the cladistic history of this group by generating a Wagner tree based on the network resulted in four equally possible trees, suggesting that further data are needed before cladogenesis in this group is resolved.     

A simple procedure for the preparation of highly purified (sodium + potassium) adenosinetriphosphatase from the rectal salt gland of Squalus acanthias and the electric organ of Electrophorus electricus.

A simple purification procedure for the Na,K-ATPase from membranes of the rectal gland of Squalus acanthias or crude microsomal fractions from the electric organ of Electrophorus electricus is presented here. The purification procedure consists of solubilization of the Na,K-ATPase with the nonionic detergent. Lubrol WX, chromatography of the diluted Lubrol extract on aminoethyl cellulose, and ammonium sulfate fractionation (1) of the concentrated eluate from the aminoethyl cellulose column. The yields of final purified enzyme are comparable to the earlier purification (1–4) involving the expensive and cumbersome zonal centrifugation stop. The purity of the final enzyme, as attested to by specific activity and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, is as great or greater than that previously reported for the enzyme purified by the procedure involving zonal centrifugation. The simplicity of the present procedure, coupled with the ready commercial availability of electric eels which are quite hardy on shipment, makes purification of the Na,K-ATPase widely available to workers in the field.     

A simple method for the addition of rotenone in Arabidopsis thaliana leaves

A simple and reproducible method for the treatment of Arabidopsis thaliana leaves with rotenone is presented. Rosette leaves were incubated with rotenone and Triton X-100 for at least 15 h. Treated leaves showed increased expression of COX19 and BCS1a, 2 genes known to be induced in Arabidopsis cell cultures after rotenone treatment. Moreover, rotenone/Triton X-100 incubated leaves presented an inhibition of oxygen uptake. The simplicity of the procedure shows this methodology is useful for studying the effect of the addition of rotenone to a photosynthetic tissue in situ.     

Effect of Methodology on the Tuberculocidal Activity of a Glutaraldehyde-Based Disinfectant

Although official guidelines recommend a plate counting method for testing the susceptibility of mycobacteria to disinfectants, manufacturers usually prefer to employ the BACTEC procedure. Data showing that the BACTEC method overestimates the activity of a glutaraldehyde-based disinfectant against Mycobacterium tuberculosis in comparison with a conventional plate counting procedure are presented.     

γ-Carboxyglutamate analysis by selective anion exchange elution and fluorescent detection

A rapid, sensitive method for the determination of free γ-carboxyglutamic acid (γ-CG) in urine and in the alkaline hydrolysates of proteins is presented. An aliquot of urine or protein hydrolysate containing added γ-[¹⁴C]CG is chromatographed on Dowex 1 employing stepwise treatments in N-(2-hydroxyethyl)piperazine-N′-2-ethanesulfonic acid buffers and final selective elution of γ-CG with MgCl₂. Aliquots of the eluted γ-CG fractions are counted to determine percentage recovery and assayed for γ-CG content by fluorescence employing o-phthalaldehyde. This procedure correlates well with direct determination of γ-CG by the established procedure of automatic amino acid analysis.     

Purification of cytochrome b-559 from oxygen-evolving Photosystem II preparations of spinach and maize

A rapid and simple procedure is presented for the purification of chloroplast cytochrome b-559. The method is based on the protocol devised by Garewal and Wasserman (Garewal, H.S. and Wasserman, A.R. (1974) Biochemistry 13, 4063–4071), which we have modified to eliminate the requirement for a lengthy electrophoretic step. Novel features of our method include: the use of oxygen-evolving Photosystem II preparations (Kuwabara, T. and Murata, N. (1982) Plant Cell Physiol. 23, 533–539) as the starting material; isocratic elution of cytochrome b-559 from a DEAE-cellulose column (yielding the protein in a pure state); and a simple column procedure for removal of excess Triton X-100. The procedure has been applied to both spinach and maize (Zea mays L.). Purified cytochromes b-559 from these species have similar optical spectra and mobility during gel electrophoresis under native conditions. Lithium dodecyl sulfate polyacrylamide gel electrophoresis of cytochrome b-559 from both spinach and maize reveals a major polypeptide band (apparent molecular mass = 9 kDa), and two minor bands (apparent molecular masses = 10 kDa and 6 kDa).     

Studies of enzyme polymorphisms in the Kamuela population of Drosophila mercatorum. II. Evaluation of glycolytic intermediates

A simple and effective cryogenic procedure for the extraction of glycolytic intermediates from whole Drosophila has been developed. This procedure gives consistent results when a measure (µM/liter/OD₂₆₀) is adopted which corrects for differences in extraction efficiency. Using this measure and a homozygous strain of D. mercatorum, there are no significant differences among extracts for the levels of any of the 15 glycolytic intermediate or energy molecules considered. The profile of means is consistent across experimental designs and instrument types. Coefficients of variation are well below 50% for most variables. The methodology presented has the statistical power to detect a mean change of 10 to 50% using an experimental design which requires as few as 32 observations. The estimated energy charge for resting Drosophila from these studies is the expected value of 0.86.     

Purification of a trifunctional enzyme, catalysing three steps of the histidine pathway, from Neurospora crassa

1. A procedure is described for the purification of an enzyme from Neurospora crassa that has three catalytic functions. These are 1-N-(5′-phosphoribosyl)-ATP pyrophosphohydrolase, 1-N-(5′-phosphoribosyl)-AMP cyclohydrolase and histidinol dehydrogenase (l-histidinol–NAD oxidoreductase, EC 1.1.1.23), and are responsible for the catalysis of reactions 2, 3 and 10 in the histidine pathway. The ratio of these three catalytic activities remains approximately the same throughout the purification procedure. Evidence is presented that the purified preparations contain a single protein exhibiting association–dissociation equilibria.     

Colorimetric screening assay for cystine plus cysteine in legume seed meals

A colorimetric assay for cystine plus cysteine in pure proteins has been adapted to legume seed meals. The procedure involves incubation of legume seed meals for 1 hr at 38°C with sodium borohydride in 8 m urea, destruction of the sodium borohydride, and colorimetric determination of thiols produced with Ellman's reagent. A comparison of values from this procedure and from performic acid oxidation of 33 legume seed meals is presented and shows good correlation for peas (Pisum sativum) and lentils (Lens culinaris), with somewhat equivocal results for beans (Phaseolus vulgaris) and fava beans (Vicia faba).     

An approach to real-time flexible scheduling

Two types of flexibility are important in manufacturing scheduling in general and in real-time scheduling in particular. The first is flexibility with respect to the criteria that can be considered in the scheduling decisions. The second is flexibility with respect to the trade-off between decision quality and computational burden: that is, the ability to arrive at a solution that makes maximum use of theavailable computational capacity and computation time. This paper describes a procedure which meets the above requirements. The procedure is justified using a theoretical analysis based on probability. Experimental results of the procedure's performance are also presented. The results show that random selection (which is used in the procedure) can play a useful role in the real-time scheduling problem.