Routine fluorescence microscopy of single untethered protein molecules confined to a planar zone

To bypass limitations of ensemble averaging biochemical analysis, microscopy‐based detection and tracking are needed for single protein molecules that are diffusing in aqueous solution. Confining the molecules to a planar zone dramatically assists tracking. Procedures of microscopy should be routine enough so that effort is focused on the biochemistry. Fluorescence microscopy and partial planar confinement of single, untethered, aqueous protein molecules have been achieved here by use of a routine procedure. With this procedure, multiple thermally diffusing Alexa 488‐stained bovine serum albumin molecules were observed during partial confinement to a thin aqueous zone next to a cover slip. The procedure produces confinement by partial re‐swelling of a previously dried agarose gel on the microscope slide. Confinement was confirmed through analysis that revealed thermal motion lower in the third dimension than it was in the plane of observation.     

CHEMICAL MODIFICATIONS OF PROTEINS: A REVIEW

The chemical modifications of proteins are reviewed. Subjects include: (1) modifications done to study protein function; (2) two naturally occurring modifications: carbonylamine reactions and reactions with nitric oxide; (3) applications for bioconjugation and mass spectral analysis; and (4) modifications of food proteins.     

6-Alkylsalicylic Acids and 6-Alkylresorcylic Acids from Ants in the Genus <Emphasis Type="Italic">Crematogaster</Emphasis> from Brunei

The defensive chemistry of two species of ants from Brunei in the genus Crematogaster (Physocrema group) has been investigated. Ants in this group release a white secretion from hypertrophied metapleural glands on their thorax when they are disturbed. Previously, one species in this group has been shown to produce alkylphenols and alkylresorcinols. In the present investigation, similar compounds along with salicylic acids and resorcylic acids that are anacardic acid and olivetolic acid homologs, respectively, are described from two species. The structures of these compounds were suggested by their spectroscopic data and confirmed by direct comparison with synthetic samples. Some of these compounds occur in lichens and have well documented physiological activities.     

Effect of LiCl on the Rate of Calcite Decomposition

The rate of decomposition of calcite powder in vacuum was measured by the Langmuir and Knudsen methods. Measured pressures in effusion cells in the absence of additives approach the equilibrium value. The Langmuir experiments gave an apparent equilibrium CO₂ pressure of =3×10⁻⁴ times the known pressure for the reaction. It is suggested that the CO₂ is in equilibrium with the calcite but the CaO is not. In Langmuir experiments, 10 wt% LiCl does not increase the initial decomposition rate. In the Knudsen cells, 10 wt% LiCl can increase the initial rate by >2 times. LiCl reduces the surface area of the product CaO under either condition from ≥30 to ∼1 m²/g. Probably an LiCl-CaO eutectic provides a solution path for CaO recrystallization and, at high CO₂ pressures, also for CaCO₃ decomposition.     

Processing of maize and sorghum in Nigeria for human consumption

Sorghum and maize are two of the major food grains grown and eaten in Nigeria. Production of these two crops averages about 4.5 million metric tons, this value representing approximately 56% of the total cereal grains produced in Nigeria for the past three years.
Although the production of these cereals has increased over the years, the effect has not been felt because of inadequate post-harvest technology especially in the area of processing. Maize and sorghum processing in Nigeria as in many other African countries is still by the traditional method of pounding in a mortar and winnowing. This method is usually performed by women, and is the major occupation for many of them. It is time consuming in that less than 2 kg of flour/hour/woman at an extraction rate of about 60% can be produced. The flour produced normally has a moisture content of 25–40% and with the rather hot climate the keeping quality is usually poor. The efforts being made through research and development to improve milling efficiency, increase the quantity of available cereal products, increase the shelf-life and eventual diversification of processed grains to replace fully or partially imported cereals for domestic and industrial uses are discussed.     

Improvements in Atmosphere Sintering of Transparent PLZT Ceramics

An improved atmosphere sintering process was developed for fabricating large transparent PLZT plates for electrooptic applications. Cold-pressed 9/85/35 PLZT slugs were sintered in O₂ in Pt crucibles for ∼45 min at 1180°C and were then heat-treated in air for 60 h at 1200°C in Al₂O₃ crucibles containing PbZrO₃ atmosphere powder. Transparent plates as large as 8.4 cm in diameter and I cm thick were thus fabricated. A mechanism is proposed which qualitatively accounts for the success of this process.