Lead Accumulation and Distribution at Cellular level in Native Plants Growing on Battery Wastes Contaminated Sites in Ibadan, Nigeria

Cells function through the complex temporal and spatial interplay of ions, metabolites, macromolecules and macromolecular assemblies. Biochemical approaches allow the investigator to define the components and the solution chemical reactions that might be involved in cellular functions. Static structural methods can yield information concerning the 2- and 3-D organization of known and unknown cellular constituents. Genetic and molecular techniques are powerful approaches that can alter specific functions through the manipulation of gene products and thus identify necessary components and sequences of molecular events. However, full knowledge of the mechanism of particular cell functions will require direct measurement of the interplay of cellular constituents. Therefore, there has been a need to develop methods that can yield chemical and molecular information in time and space in living cells, while allowing the integration of information from biochemical, molecular and genetic approaches at the cellular level.

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Gap junctions in the prothoracic glands of the tobacco hornworm, Manduca sexta

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123933 ◽

1992 ◽

Vol 50 (1) ◽

pp. 706-707

Author(s):

Ji-da Dai ◽

M. Joseph Costello ◽

Lawrence I. Gilbert

Keyword(s):

Gap Junctions ◽

Small Molecules ◽

Manduca Sexta ◽

Freeze Fracture ◽

Cell Communication ◽

Cellular Level ◽

Thin Sections ◽

Prothoracic Glands ◽

Polyhydroxylated Steroids ◽

Stimulation Of

Insect molting and metamorphosis are elicited by a class of polyhydroxylated steroids, ecdysteroids, that originate in the prothoracic glands (PGs). Prothoracicotropic hormone stimulation of steroidogenesis by the PGs at the cellular level involves both calcium and cAMP. Cell-to-cell communication mediated by gap junctions may play a key role in regulating signal transduction by controlling the transmission of small molecules and ions between adjacent cells. This is the first report of gap junctions in the PGs, the evidence obtained by means of SEM, thin sections and freeze-fracture replicas.

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Biomedical applications: Pitfalls in the practice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169626 ◽

1994 ◽

Vol 52 ◽

pp. 378-379

Author(s):

J. D. Shelburne ◽

Peter Ingram ◽

Victor L. Roggli ◽

Ann LeFurgey

Keyword(s):

Operating Room ◽

Liquid Nitrogen ◽

Lung Tissue ◽

Biomedical Applications ◽

Microprobe Analysis ◽

Tissue Sample ◽

Cellular Level ◽

Tissue Samples ◽

Asbestos Fibers

At present most medical microprobe analysis is conducted on insoluble particulates such as asbestos fibers in lung tissue. Cryotechniques are not necessary for this type of specimen. Insoluble particulates can be processed conventionally. Nevertheless, it is important to emphasize that conventional processing is unacceptable for specimens in which electrolyte distributions in tissues are sought. It is necessary to flash-freeze in order to preserve the integrity of electrolyte distributions at the subcellular and cellular level. Ideally, biopsies should be flash-frozen in the operating room rather than being frozen several minutes later in a histology laboratory. Electrolytes will move during such a long delay. While flammable cryogens such as propane obviously cannot be used in an operating room, liquid nitrogen-cooled slam-freezing devices or guns may be permitted, and are the best way to achieve an artifact-free, accurate tissue sample which truly reflects the in vivo state. Unfortunately, the importance of cryofixation is often not understood. Investigators bring tissue samples fixed in glutaraldehyde to a microprobe laboratory with a request for microprobe analysis for electrolytes.

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