University of Tennessee Health Science Center

About: University of Tennessee Health Science Center is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Medicine. The organization has 15716 authors who have published 26884 publications receiving 1176697 citations.

A triclosan-resistant bacterial enzyme

Abstract: Triclosan is an antimicrobial agent that is widely used in a variety of consumer products and acts by inhibiting one of the highly conserved enzymes (enoyl-ACP reductase, or FabI) of bacterial fatty-acid biosynthesis. But several key pathogenic bacteria do not possess FabI, and here we describe a unique triclosan-resistant flavoprotein, FabK, that can also catalyse this reaction in Streptococcus pneumoniae. Our finding has implications for the development of FabI-specific inhibitors as antibacterial agents.

Multiple adhesins of streptococci.

Abstract: Human streptococcal isolates are confronted with numerous environmental challenges, one of which is the necessity that they adhere to one or more of the varied mucosal surfaces of the oropharyngeal cavity between their point of entry into the host and the site where physiological conditions favor colonization. They interact with buccal cells, tonsillar cells, salivary constituents, and dental pellicles and with other bacteria and their products. To maintain themselves in these environments, the streptococci must be able to interact with different receptors on the distinct surfaces (5, 6, 31). It is not surprising, therefore, that evolutionary pressures would select organisms that are genetically capable of producing more than one class or type of adhesin. Indeed, the concept of multiple adhesins has been recognized for over 20 years for gram-negative bacteria, especially members of the family Enterobacteriaceae (27). There is, in fact, no need to bring attention to the concept of multiple adhesins in gram-negative bacteria, so widespread is its acceptance (32). The concept of multiple steps in the process of adhesion has also been proposed for gram-negative bacteria, such as enteropathogenic Escherichia coli (46) and Mycoplasma pulmonis (51). However, it was more recently that a sufficient body of data accumulated to suggest that similar to gram-negative bacteria, gram-positive bacteria also express multiple adhesins and, further, that the adhesins probably function in distinct kinetic steps. While these are not new concepts, they are not yet widely recognized or accepted for streptococci. It is these concepts that we wish to address, primarily with respect to human streptococcal isolates. For illustration, we shall focus on two streptococcal species that inhabit different niches of the upper respiratory tract. One, Streptococcus sanguis, colonizes the tooth surface, and the other, Streptococcus pyogenes, colonizes the pharynx and tonsils. We will attempt to marshall the evidence for the expression of multiple adhesins in these species (and perhaps other gram-positive cocci) and develop

EclampsiaVIII. Risk factors for maternal morbidity

Abstract: The distribution of synapses formed by corticostriatal neurons was measured to determine the average connectivity and degree of convergence of these neurons and to search for spatial inhomogeneities. Two kinds of axonal fields, focal and extended, and two striatal tissue compartments, the patch (striosome) and matrix, were analyzed separately. Electron microscopic examination revealed that both kinds of corticostriatal axons made synapses at varicosities that could be identified in the light microscope, and each varicosity made a single synapse. Thus, the distribution of varicosities was a good estimate of the spatial distribution of synapses. The distance between axonal varicosities was measured to determine the density of synaptic connections formed by one axon within the volume occupied by a striatal neuron. Intersynaptic distances were distributed exponentially, except that synapses were rarely located

Connectivity and convergence of single corticostriatal axons

Abstract: The distribution of synapses formed by corticostriatal neurons was measured to determine the average connectivity and degree of convergence of these neurons and to search for spatial inhomogeneities. Two kinds of axonal fields, focal and extended, and two striatal tissue compartments, the patch (striosome) and matrix, were analyzed separately. Electron microscopic examination revealed that both kinds of corticostriatal axons made synapses at varicosities that could be identified in the light microscope, and each varicosity made a single synapse. Thus, the distribution of varicosities was a good estimate of the spatial distribution of synapses. The distance between axonal varicosities was measured to determine the density of synaptic connections formed by one axon within the volume occupied by a striatal neuron. Intersynaptic distances were distributed exponentially, except that synapses were rarely located