scholarly journals THE HUMAN CHROMOSOME

1969 ◽  
Vol 41 (1) ◽  
pp. 73-90 ◽  
Author(s):  
J. G. Abuelo ◽  
Dorothy E. Moore
Keyword(s):  
Tissue Culture ◽  
Electron Microscope ◽  
Human Chromosome ◽  
Critical Point ◽  
Human Lymphocytes ◽  
Langmuir Trough ◽  
Trypsin Treatment ◽  
Short Term ◽  
Dnase Digestion ◽  
Critical Point Drying

Human lymphocytes were grown in short-term tissue culture and were arrested in metaphase with Colcemid. Their chromosomes were prepared by the Langmuir trough-critical point drying technique and were examined under the electron microscope. In addition, some chromosomes were digested with trypsin, Pronase, or DNase. The chromosomes consist entirely of tightly packed, 240 ± 50-A chromatin fibers. Trypsin and Pronase treatments induce relaxation of fiber packing and reveal certain underlying fiber arrangements. Furthermore, trypsin treatment demonstrates that the chromatin fiber has a 25–50 A trypsin-resistant core surrounded by a trypsin-sensitive sheath. DNase digestion suggests that this core contains DNA.

Pulmonary microcirculation: tubules rather than sheet and post

1982 ◽  
Vol 53 (2) ◽  
pp. 510-515 ◽  
Author(s):  
W. G. Guntheroth ◽  
D. L. Luchtel ◽  
I. Kawabori
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Critical Point ◽  
Ringer Solution ◽  
Basic Component ◽  
Pulmonary Vasculature ◽  
Critical Point Drying ◽  
Pulmonary Microcirculation ◽  
Scanning Electron

We examined latex casts of the pulmonary microcirculation with the scanning electron microscope (SEM). Mature rats were anesthetized and ventilated; the pulmonary vasculature was washed out with lactated Ringer solution and then filled with a mixture of Geon latexes. The airways were filled with glutaraldehyde with resulting transmural vascular pressures of 10 cmH2O. After critical-point drying and corrosive removal of the lung tissue, SEM studies of the vascular replicas revealed two distinct patterns of pulmonary microcirculation: 1) sparse, long, tubular capillaries that comprise the thin subpleural layer and appear as “filler” in the peribronchial spaces; and 2) alveolar microcirculation that is composed of tightly matted, intersecting tubules, shorter but of the same diameter as type 1, in spherical array in two layers. The alveolar capillaries at low magnification appear superficially as sheets; however, the detailed morphology is not consistent with the sheet-and-post model. We conclude that the basic component of the pulmonary microcirculation is tubular and not different from other capillary beds except in density.

Alteration of the antigenicity of human lymphocytes by plant lectins and short-term tissue culture

1975 ◽  
Vol 19 (2) ◽  
pp. 306-317 ◽  
Author(s):  
Joshua Miller ◽  
Judith Lifton ◽  
Brack G. Hattler
Keyword(s):  
Tissue Culture ◽  
Human Lymphocytes ◽  
Short Term ◽  
Plant Lectins

A comparison of microstructures of Cheddar cheese curd manufactured with calf rennet, bovine pepsin, and porcine pepsin

1976 ◽  
Vol 43 (1) ◽  
pp. 113-115 ◽  
Author(s):  
M. F. Eino ◽  
D. A. Biggs ◽  
D. M. Irvine ◽  
D. W. Stanley
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Critical Point ◽  
Cheddar Cheese ◽  
Microscope Examination ◽  
Porcine Pepsin ◽  
Electron Microscope Examination ◽  
Critical Point Drying ◽  
Cheese Curd ◽  
Scanning Electron

SummaryCalf rennet, bovine pepsin, and porcine pepsin were used to produce cheese curd, using the same milk and lactic culture for each. Specimens were prepared for scanning electron microscope examination by a modified critical-point drying technique.From examination of the micrographs, the curd made with bovine and porcine pepsin were similar in structure and in orientation of the coagulated protein, whereas the curd produced with rennet was different, having a more compact and organized structure.

scholarly journals THE STRANDEDNESS OF MEIOTIC CHROMOSOMES FROM ONCOPELTUS

1966 ◽  
Vol 31 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Stephen L. Wolfe ◽  
Godfrey M. Hewitt
Keyword(s):  
Electron Microscope ◽  
Critical Point ◽  
Living Cells ◽  
Point Method ◽  
Oncopeltus Fasciatus ◽  
Langmuir Trough ◽  
Ringer’S Solution ◽  
Meiotic Chromosomes ◽  
Parallel Folding

Meiotic chromosomes were isolated from male Oncopeltus fasciatus by dissecting the testes under insect Ringer's solution and spreading the living cells on the Langmuir trough. After being dried by the critical point method, preparations were examined under the electron microscope. Chromosomes at all stages of prophase prove to be multistranded. A significant increase in the number of parallel 250 A fibers in the chromosomes occurs between zygotene and diakinesis. Parallel folding, rather than true multistrandedness, is interpreted as the mechanism responsible for this observed increase in multistrandedness. It has not been possible to determine whether the multistrandedness observed at leptotene represents true multistrandedness or is the result of parallel folding. Apparent multistrandedness is lost at metaphase when the 250 A fibers of the chromosomes become coiled more tightly. In preparations isolated by these methods, no structures other than the 250 A chromosome fibers are visible in the chromomeres, which appear as regionally coiled or folded areas of the fibers along the arm of the chromosome.

The Fine Surface Structure of the Male Genital Bulb of the Dwarf Spider Catabrithorax Plumosus

1988 ◽  
Vol 46 ◽  
pp. 282-283
Author(s):  
C Cady ◽  
R. V. Cyrus ◽  
J. L. Kaspar
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Critical Point ◽  
Amyl Acetate ◽  
Critical Point Drying ◽  
Fine Surface ◽  
Genital Structure ◽  
Ethanol Series ◽  
Scanning Electron ◽  
Male Genital

The spider Catabrithorax plumosus (Emerton) family Linyphiidae, subfamily Erigoninae is a member of an abundant yet reclusive group known as the dwarf spiders. Collectively, these are the smallest spiders in North America. Most measure only 1-3 mm in length, creating difficulties in indentification. The morphology of the male genital bulb, located on the distal pedipalp, is of great importance to the taxonomist in identifying spiders to the species level. This study examines the complex male genital structure in both the expanded and unexpended condition by means of the Scanning Electron Microscope (SEM).Pedipalps were removed at the trochanter-femur articulation, dehydrated in 70% ethanol and expanded by Immersion in lactic acid for 6-8 h. After complete expansion a graded amyl acetate series preceeded critical point drying. Unexpanded palps were dehydrated in an ethanol series followed by a graded amyl acetate series in ethanol. Specimens were critical point dried from CO2 and given an evaporated coating of carbon-gold. Specimens were examined in a Hitachi HHS-2R Scanning Electron Microscope operating at an accelerating voltage of 10 kV.

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