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Biomedical subjects

C R MacKenzie

Publications and source records attributed to C R MacKenzie.

97 records · Page 6Linked to original sources
PubMed1977

Glycogen synthesis by amylosucrase from Neisseria perflava.

Amylosucrase (sucrose:1,4-alpha-D-glucan 4-alpha-glucosyltransferase; EC 2.4.1.4) which mediates the transfer of the glucosyl moiety of sucrose to a growing alpha-1,4-glucan chain is a constitutive enzyme of Neisseria perflava. The products of enzymic action are insoluble glycogenlike polysaccharides and fructose, the latter being a competitive inhibitor of the enzyme (Ki=20 mM). The enzyme is extremely stable and appears to bind very tightly to its polymerized product. Properties of product-bound enzyme reflect those of the native complex.

Cell-Free System↗
PubMed1973

Ultrastructure of free-living and nitrogen-fixing forms of Rhizobium meliloti as revealed by freeze-etching.

Freeze-etching of Rhizobium meliloti provided considerable insight into the ultrastructure of this bacterium and into the changes accompanying the transformation from the free-living rod forms to the nitrogen-fixing bacteroid forms. In the small rods, one cleavage plane was revealed at the level of the cell wall and a second at the level of the plasma membrane. Very little structure was evident at the cell wall level, but distinctly different convex and concave fracture faces were exposed at the cell membrane cleavage plane. During the transformation into the bacteroidal state the wall decreased in thickness, became less rigid, and developed a particulate surface. In addition, changes in particle density were observed in the plasma membrane. The fine structure of the plant membranes, the infection threads, and the arrangement of the bacteroids within the plant cells also were revealed.

Cell Membrane↗
PubMedDate not supplied

Tendon involvement in a case of ochronosis.

A patient with severe skeletal and systemic involvement due to ochronosis is reported. On radiographic examination there was a linear density attached to the left lesser trochanter. The possible role of ochronotic pigment deposition in tendon, leading to metaplastic bone formation, is discussed.

Calcinosis↗