An Inexpensive Microscope Lamp for Critical Illumination

A microscope lamp with light of adjustable intensity, which will afford critical illumination of a quality satisfactory for the most exacting cytological work, can be constructed for about $7.50. The essential parts needed are: auto headlight bulb, radio power transformer, radio “potentiometer”, and simple plano-convex lens. A ground glass is not used with 4 and 2 mm. objectives, a solid source of light being obtained by placing the bulb so that one filament coil is directly behind the other. This light source is brought to a focus by the condensing lens at a field diaphragm and this image is projected by the microscope condenser into the plane of focus of the microscope.     

An Inexpensive Microphotometer System for Measuring Silver Grain Densities in Autoradiographs

An inexpensive microphotometric system is described which will facilitate reading grain-dense areas in autoradiographic material. It is reliable, easy to operate and adaptable to most light microscopes with a dark field condenser. in addition to the microscope, the components include a photodiode, an operational amplifier and a digital mV meter. Data are presented to demonstrate the sensitivity of the system and to illustrate the differential variability between the microphotometer ad the counting of grains by eye.     

An Inexpensive Apparatus for Automatic Continuous Dehydration

An apparatus is described for automatic dehydration of material using the principle of continuous dilution. Specimens may be dehydrated, in a period chosen by the operator, for as little as 30 min to as much as 16 hr (overnight). The apparatus is inexpensive both to construct and to run.     

Gas Flow Measurement in Fermentations: An Inexpensive System with Analogue Output for Recording

During the fermentation of North Sea Gas to single cell protein in a gas-recycle system (Spivey 1973) there was a need to measure continuously low gas flow rates and to obtain a recorder signal proportional to the instantaneous flow rate. Commercial equipment, such as differential pressure transmitters linked to a pneumatic recorder, was expensive and not readily modified for the low flow rates of laboratory fermentations.     

An Inexpensive Vibrating Microtome for Sectioning Fixed Tissue

A tissue sectioner which uses a vibrating razor blade and a simple mechanism for the elevation of the tissue can be constructed for less than fifty dollars. The razor blade is fixed to the vibrator of a hair clipper and a nut and bolt serve as the tissue advance mechanism. A metal disc attached to the nut is used for the stage. The tissue advance mechanism is placed inside a machined teflon cylinder which provides a smooth surface upon which the razor assembly is moved. Fixed tissue may be sectioned uniformly at a thickness of 50 μm or more. This device has the advantages of portability, rapidity of sectioning, and inexpensive construction.     

Development of Low-Cost Inverted Microscope to Detect Early Growth of Mycobacterium tuberculosis in MODS Culture

Background

The microscopic observation drug susceptibility (MODS) assay for rapid, low-cost detection of tuberculosis and multidrug resistant tuberculosis depends upon visualization of the characteristic cording colonies of Mycobacterium tuberculosis in liquid media. This has conventionally required an inverted light microscope in order to inspect the MODS culture plates from below. Few tuberculosis laboratories have this item and the capital cost of $5,000 for a high-end microscope could be a significant obstacle to MODS roll-out.

Methodology

We hypothesized that the precise definition provided by costly high-specification inverted light microscopes might not be necessary for pattern recognition.

Significance

In this work we describe the development of a low-cost artesenal inverted microscope that can operate in both a standard or digital mode to effectively replace the expensive commercial inverted light microscope, and an integrated system that could permit a local and remote diagnosis of tuberculosis.     

An Electron Microscope Study of Myelin Figures

In the electron microscope, thin sections of OsO₄-fixed myelin figures from the phospholipide fraction of human brain show a pattern of parallel dark lines with a repeating period of about 40 A. It is shown that the dark lines probably represent the reaction product of OsO₄ with double bonds in the fatty acid chains, thereby marking the central portion of one bimolecular lamella. The addition of globin results in dense lines 25 to 50 A wide that cover the surface of the myelin figures. When such a figure consists of only two bimolecular leaflets of lipide covered with globin, the structure shows striking similarity to the image of cell membranes in fixed tissue sections. A hypothetical schema is given of the molecular structure of the figure, and the distribution of OsO₄ in it.     

An Efficient Rice Transformation System Utilizing Mature Seed-derived Explants and a Portable,Inexpensive Particle Bombardment Device

We developed a practical and efficient gene transfer system for indica rice utilizing mature-seed derived explants and a simple bombardment device which uses compressed helium for accelerating DNA-coated metal particles. Unlike instruments which have been described in the literature previously, this new bombardment device, which is an improvement of the particle inflow concept, does not require vacuum. This attribute simplifies the transformation procedure significantly and it makes rice transformation technology accessible to laboratories which may not have the resources to invest in more expensive particle bombardment instruments. We determined experimentally that we could recover transgenic rice plants utilizing three different particle bombardment instruments at comparable frequencies.     

An Inexpensive Apparatus Facilitating the Storage of Oxygen Sensitive Compounds

The design, construction, and use of an inexpensive apparatus which facilitates the storage of oxygen sensitive compounds in serum bottles is described.     

An Excellent and Inexpensive Substitute for Immersion Oil in Microscopy

Commercial immersion oils are recommended for microscopy because their refractive index of 1.515 matches that of the crown glass of oil immersion objectives. Some of the oils offered in the past have been less than ideal. Thickened cedarwood oil is prone to drying and could be difficult to remove if allowed to do so (Lillie and Fullmer 1976). Until 1976 immersion oils manufactured in the United States often contained substantial proportions of polychlorinated biphenyls (PCBs), now recognized as highly dangerous toxins (Nashel and Fischmann 1983). A substitute was therefore sought that would be free of such objections.     

Inexpensive low-oxygen incubators

Although the evidence is overwhelming that ambient oxygen is at least somewhat damaging to most normal cells in culture, the expense and effort involved has resulted in few laboratories growing their cells under physiological oxygen conditions. We here describe how to produce, from commercially available plastic wide-mouth jars, very simple gas-tight containers that can be flushed with prepared gas mixtures to produce low-oxygen environments for standard cell culture. This permits any laboratory to easily try the effects of physiological oxygen on their system without the need for dedicated incubators and substantial monetary investments.     

Inexpensive Laboratory-Constructed Nephelometer

An inexpensive, simple-to-construct nephelometer which was used to monitor the lysis of spheroplasts is described. The nephelometer is a flow-through device with a linear response to cell concentration from the lower detection limit to 8 × 10⁸ cells per ml.     

An Electron Microscope Study of the Rat Ovum

This paper reports on the fine structure of rat oocytes at stages before ovulation, during maturation, fertilization, and early cleavage. The study includes parallel observations on light and electron microscope preparations with attempted correlations. The follicular cells of the ovarian egg are described as sending long processes through the zona pellucida to the egg surface where they mingle with thin projections from the egg itself. No open communication between follicle cell cytoplasm and egg cytoplasm was observed. During maturation and fertilization both types of processes are withdrawn from the zona. The germinal vesicle and later the pronuclei of the fertilized egg are characterized by numerous large nucleoli. These have the form of thick walled vesicles with diameters as great as 8 to 10 µ. The wall is dense in the EM image and appears to consist in part of small granules. The cytoplasm shows several inclusions including mitochondria of usual form and a Golgi component which has the typical fine structure and the distribution described by earlier light studies. Small dense particles, presumably RNP particles, are distributed throughout the cytoplasmic matrix and show no preference for membranes. The endoplasmic reticulum of the oocyte is represented by a scattering only of vesicles, but begins a more extensive and elaborate development with the onset of segmentation. One inclusion of the ooplasm, similar in size to mitochondria, receives special attention. It is a vesicular structure, containing a large number of small vesicles (10 to 50 mµ in diameter) and frequently a central density or nucleoid. They are referred to as multivesicular bodies. Such bodies are found in small number in the ovarian egg, but increase greatly in number during maturation and fertilization. It appears from the micrographs of eggs in these latter stages that these vesicular bodies break down and liberate their content of small vesicles to the surrounding ooplasm. Comments are provided on the apparent significance of the various observations.