A Plexiglas Isolation-Transfer Chamber for Use with the Fonbrune Micromanipulator

The chamber is made with two pieces of clear Plexiglas, both 1 inch wide and 3 inches long; the top piece, 1/16 inch thick; the bottom, 1/4 inch. A recess 14 mm wide, 37 mm long and 5 mm deep is cut into the bottom piece leaving a margin 1.5 mm wide, this margin is then cut down to a height of 2.5 mm for the length of the recess; a piece of moistened filter paper I1/2 inches long and 5 mm deep is attached to the rear wall, leaving the bottom clear for the transmitted light; two notches 13 × 15 mm and 12 mm apart are cut from the top piece. The top is superimposed on the bottom and held by two screws to form a chamber that is accessible to microdissection instruments through its open side. Two cover glasses, one bearing the specimen and the other, the medium to which the transfer is to be made, are placed over the notches in the top (agar side down). The actual transfer of material is made by shifting the position of the cover glasses with the mechanical stage of the microscope while the specimen is held by the micromanipulator.     

Micromanipulator for Yeast Genetic Studies

An inexpensive mechanical micromanipulator, designed primarily for separating yeast ascospores, can be assembled from commercially available components and without extensive custom machining.     

A versatile apparatus for polyacrylamide and agarose gel electrophoresis in Plexiglas slab gel molds

A simple vertical slab gel electrophoresis apparatus for analytical, preparative, and two-dimensional electrophoresis is described. The use of permanently sealed Plexiglas acrylic plastic slab gel molds which need to be sealed only at the bottom during gel formation, rather than the glass plate sandwich used in most previous designs, virtually eliminates leakage during gel formation and, in addition, permits the continuous monitoring with ultraviolet light of proteins and nucleic acids labeled with fluorescent dyes during electrophoresis. Results obtainable with this apparatus are equivalent to those achieved in other apparati which are more expensive to fabricate or purchase.     

介绍一项用于单孢子分离和制片以备显微摄影的显微操作技术

<正>作者于1981年秋季在加拿大滑铁卢大学B. Kendrick博士的真菌学实验室见到日本真菌学家松岛崇(T.M:tsshim)先生曾用一台自装的显微操作装置进行真菌的单抱子分离,;既迅速又准确。并用这种装置在载玻片上移动和重新排列真菌抱子或其它抱子器宫,     

Use of the Pressure Chamber in Membrane Damage Studies

The ability to detect membrane damage in plant leaves by thepressure chamber technique was evaluated. Membrane damage wasinduced by freezing and thawing, absorption of the host-specifictoxin victorin, ozonation, inoculation with Helminthosporiummaydis, and spraying with the phytotoxin, fusicoccin. The pressure-volumerelationships, i.e. the volume of sap expressed from a leafwith incremental increases in pressure, were compared in leaveswith intact or damaged membranes. Where membrane damage waswidespread throughout the leaf, sap was expressed at pressuresas low as one tenth of those needed in leaves with intact membranesand at low pressures the amount of water expressed from leaveswith damaged membranes was up to 10 times that from leaves withintact membranes. Further, the pressure-volume curves of healthyleaves became linear when the leaf turgor potential was reducedto zero, but were non-linear in leaves with damaged membranes.Ozone treatment, inoculation with H. maydis, or spraying withfusicoccin damaged only a proportion of the leaf cells, andpressure-volume relationships more nearly resembled those obtainedwith healthy leaves rather than those obtained with freezingand thawing and absorption of victorin. It is concluded that the pressure chamber can be used to observemembrane integrity, but its ability to detect damage may belimited to conditions in which the majority of cells in theleaf are damaged.     

A Perfusion Chamber with Temperature Regulation

When investigating microscopic preparations perfusion chambers allow exchange and regulation of different solutions and ensure their constant flow in the sample chamber. Temperature deviations, however, may be problematic. We describe a new chamber that contains an additional circulation system which regulates the inside temperature using an external thermostat. An integrated thermometer probe records the sample temperature, which appears on a monitor. The glass chamber. measuring 75 × 35 × 3 mm, provides good optical quality and is compatible with every type of microscope.     

A Microperfusion Chamber for Studying the Growth of Bacterial Cells

A microperfusion chamber for studying the growth of bacterial cells is described. It can be used with unmodified phase contrast systems. Both temperature and the composition of the growth medium can be changed by the operator during observation of bacteria. The use of the chamber is illustrated with observations on the effect of penicillin on Arthrobacter globiformis .     

A Comparison of Phytoplankton and Algae Growing on Plexiglas Slides in an Oligotrophic Lake

This study compares the composition and dynamics of phytoplankton communities and of periphyton communities growing on Plexiglas slides in a temperate oligotrophic lake. Ordination methods were used in the comparisons, which covered a three-month period during the summer. Plankton and periphyton communities differed considerably, and shared only six common taxa. An ephemeral Dinobryon pulse occurred simultaneously in both communities, and represented the largest source of variability in community composition. Recovery from the pulse was faster in the phytoplankton than in the periphyton. Attachment to substrata, through its effect on cell turnover times and nutrient cycling, is hypothesized to provide a temporal refuge for plankton species during periods of unfavorable environmental conditions.     

The Use of the Pressure Chamber Technique for Measurement of the Water Potential of Transpiring Plant Organs

The existence of water potential gradients in flowering shoots and leaves of roses (Rosa sp., cv. Baccara) and along flag leaves of wheat (Triticum aestivum L.) were studied by means of the Scholander pressure chamber. In roses grown in greenhouse, the water potential measured in transpiring shoots was higher than in leaves detached from these shoots, whereas the potential differences between leaf and shoot after equilibration in the dark were small or negligible. A progressive decrease in water potential was found upon repeated measurement on the same organ; this decline was steeper in leaves than in shoots. Extrapolating this decline to excision time resulted in water potential values which, in transpiring shoots, were 3 to 5 bars higher than in leaves. Detopping the flower bud did not alter this pattern, indicating that the highest water potential in the shoot was in the stem. In field-grown wheat, the water potential measured in a whole flag leaf was about 6 bars higher than that measured in the apical one-third of the leaf, and this difference disappeared after equilibrating the detached leaf for 1 h in the dark. These potential differences indicate the presence of resistances along the water path in the organ. The results obtained by the pressure chamber represent the highest water potential in the organ, rather than the average water potential.     

A New Chamber for Studying the Behavior of Drosophila

Methods available for quickly and objectively quantifying the behavioral phenotypes of the fruit fly, Drosophila melanogaster, lag behind in sophistication the tools developed for manipulating their genotypes. We have developed a simple, easy-to-replicate, general-purpose experimental chamber for studying the ground-based behaviors of fruit flies. The major innovative feature of our design is that it restricts flies to a shallow volume of space, forcing all behavioral interactions to take place within a monolayer of individuals. The design lessens the frequency that flies occlude or obscure each other, limits the variability in their appearance, and promotes a greater number of flies to move throughout the center of the chamber, thereby increasing the frequency of their interactions. The new chamber design improves the quality of data collected by digital video and was conceived and designed to complement automated machine vision methodologies for studying behavior. Novel and improved methodologies for better quantifying the complex behavioral phenotypes of Drosophila will facilitate studies related to human disease and fundamental questions of behavioral neuroscience.     

A Remodeled Tissue Flattener for Use with the International Microtome Cryostat

The antiroll plate is cut from a standard microscope slide, a 2 cm length, to give a 2 × 2.5 cm piece. This is fitted into inside grooves of a movable metal frame which is held by a hinge joint parallel to the back of the microtome knife. A stationary frame, which supports the hinged member, has spring clips welded to its sides for attachment to the knife. Clearance between the antiroll plate and knife is obtained by applying Scotch tape to the edge of the plate that is adjacent to the knife edge. The hinge permits the plate to be swung back and thus clear the knife surface.