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Biomedical subjects

J London

Publications and source records attributed to J London.

At least 109 records · Page 6Linked to original sources
PubMed1978

Peanut agglutinin. I. A new tool for studying T lymphocyte subpopulations.

Fluorescein-coupled peanut agglutinin (PNA) has been used at the single-cell level to study mouse lymphocyte subpopulations. PNA not only binds to most thymocytes, as has already been shown by other authors, but also binds to a small fraction of peripheral lymphocytes that are all T cells (theta+Ig-) or null cells (theta-Ig-). Most PNA-positive thymocytes are sensitive to in vivo corticosteroids and irradiation (450 rads) treatments. Conversely, the positive spleen cells (5% of total spleen lymphocytes) are essentially resistant to corticosteroids and irradiation. Study of PNA binding during ontogenesis shows the occurrence of PNA-positive cells in the fetal liver before thymus constitution and in the very beginning of embryonic thymus and spleen development. These data indicate that PNA is a marker of early T cell subpopulations but that there are probably several distinct subsets of PNA-positive T cells.

Animals↗
PubMed1977

New pathway for the metabolism of pentitols.

Certain strains of Lactobacillus casei can grow at the expense of one or more pentitols. These microorganisms possess a pentitol phosphate pathway that appears to be analogous to the hexitol phosphate pathway found in many facultatively anaerobic bacteria. Pentitol is transported into the cell by a phospho enolpyruvate phosphotransferase system that converts it to pentitol phosphate, whereupon a specific dehydrogenase oxidizes the intermediate product to ketopentose phosphate. The ketopentose phosphate is subsequently converted to xylulose-5-P and enters one of the pathways of central metabolism.

Journal Article↗
PubMed1976

Aldolases of the lactic acid bacteria. Demonstration of immunological relationships among eight genera of Gram positive bacteria using an anti-pediococcal aldolase serum.

Reciprocal qualitative and quantitative immunological experiments employing an anti-Pediococcus cerevisiae aldolase serum confirmed many of the interspecific relationships demonstrated previously among lactic acid bacteria with antisera prepared against the Streptococcus faecalis fructose diphosphate aldolase. The extent of immunological relatedness observed between the Lactobacillus and Pediococcus aldolases was markedly gses indicating that the pediococci share closer phylogenetic ties with the rod-shaped lacotbacilli than with their spherical counterparts in the streptococci. In addition to confirming the existence of definitive, but distant, relationships between the lactic acid bacteria and certain gram positive nonsporeforming anaerobes, immunological cross-reactivity was also demonstrated between the pediococcal aldolases and those of Aerococcus viridans.

Biological Evolution↗
PubMed1976

Ultrasonic diagnosis of a popliteal artery aneurysm.

Ultrasound techniques are very effective in screening painful masses of the popliteal space. These techniques easily differentiate popliteal cysts from thrombophlebitis, and in addition permit sequential evaluation without patient discomfort or invasion. We report its use in diagnosing a popliteal artery aneurysm, another cause of a painful popliteal mass.

Aged↗
PubMed1971

Comparative biochemical and immunological study of malic enzyme from two species of lactic acid bacteria: evolutionary implications.

Representatives of both Streptococcus faecalis and Lactobacillus casei produce isofunctional malic enzymes. All 10 strains of S. faecalis tested could be induced to synthesize malic enzyme and readily adapted to growth on malate. Although 17 of 21 L. casei strains could be induced to produce malic enzyme, only 9 of 14 strains tested grew at the expense of malate. A comparison of catalytic and regulatory properties suggested that the malic enzymes from S. faecalis and L. casei were very similar. Immunological analyses showed that the numerous similarities in function actually reflected partial protein homologies; however, two distinct forms of the malic enzyme were detected among different strains of L. casei by immunochemical and serological procedures. The division of L. casei into two subgroups based on the immunological type of malic enzyme synthesized corresponds to two subspecies currently recognized by microbial taxonomists.

Acrylates↗
PubMed1971

Detection of relationships between Streptococcus faecalis and Lactobacillus casei by immunological studies with two forms of malic enzyme.

Antisera prepared against two isologous malic enzymes from Lactobacillus casei strains 64H and M40 were used to survey and categorize the various malic enzymes found within this diverse species. In addition to detecting three major antigenic variants of malic enzyme within this group, both antisera readily reacted with Streptococcus faecalis malic enzyme. The cross-reactions between the L. casei malic enzyme antisera and the S. faecalis malic enzyme indicated that these iso-functional enzymes found in two apparently diverse groups of organisms were immunologically homologous. A scheme proposing a common ancestry for the two species S. faecalis and L. casei based on the results of quantitative immunological studies is presented.

Animals↗
PubMed1970

Malate utilization by a group D Streptococcus: regulation of malic enzyme synthesis by an inducible malate permease.

Induction of an nicotinamide adenine dinucleotide-specific malic enzyme and a malate entry system permits Streptococcus faecalis to grow at the expense of malate. Evidence is presented which shows that biosynthesis of the permease, but not of the malic enzyme, is subject to catabolite repression by glucose. In contrast to the malic enzyme, the catalytic function of the entry system does not appear to be inhibited by intermediate products of glycolysis. Although the induction of the entry system does not appear to be coordinated with the induction of the malic enzyme, the latter process is dependent upon the permease for the transport and accumulation of inducer.

Carbon Isotopes↗