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J W Booth

Publications and source records attributed to J W Booth.

7 recordsLinked to original sources
PubMed1997

Phosphate transport in yeast vacuoles.

The vacuole of the yeast Saccharomyces cerevisiae is a major storage compartment for phosphate. We have measured phosphate transport across the vacuolar membrane. Isolated intact vacuoles take up large amounts of added [32P]phosphate by counterflow exchange with phosphate present in the vacuoles at the time of their isolation. The bidirectional phosphate transporter has an intrinsic dissociation constant for phosphate of 0.4 mM. Exchange mediated by this carrier is faster than unidirectional efflux of phosphate from the vacuoles. The transporter is highly selective for phosphate; of other anions tested, only arsenate is also a substrate. Transport is strongly pH-dependent with increasing activity at lower pH. Similar phosphate transport behavior was observed in right-side-out vacuolar membrane vesicles.

Biological Transport↗
PubMed1995

An alleged yeast polyphosphate kinase is actually diadenosine-5', 5"'-P1,P4-tetraphosphate alpha,beta-phosphorylase.

Polyphosphates are a major constituent of the yeast Saccharomyces cerevisiae. A purification of the enzyme polyphosphate kinase (E.C. 2.7.4.1) from this organism has been reported (Felter, S., and Stahl, A.J.C. (1973) Biochimie (Paris) 55, 245-251). The assay for activity used in this purification was the production of 32P-labeled nucleotide, presumed to be ATP, in the presence of [32P]polyphosphate and ADP. We have found that this assay does not reflect the activity of a polyphosphate kinase but rather the combination of an exopolyphosphatase, releasing free [32P]phosphate from the added [32P]polyphosphate, and the ADP-[32P]phosphate exchange activity of the enzyme diadenosine 5',5"'-P1, P4-tetraphosphate alpha, beta-phosphorylase (Ap4A phosphorylase). We also present direct evidence for the formation of an enzyme-AMP intermediate in the actin of Ap4A phosphorylase.

Adenosine Monophosphate↗
PubMed1993

Explaining glomerular pores with fiber matrices. A visualization study based on computer modeling.

The extracellular space of the glomerular capillary wall is occupied by a complex meshwork of fibrous molecules. Little is understood about how the size, shape, and charge recognition properties of glomerular ultrafiltration arise from this space-filling fiber matrix. We studied the problem of size recognition by visualizing the void volume accessible to hard spheres in computer-generated three-dimensional homogeneous random fiber matrices. The spatial organization of the void volume followed a complex "blob-and-throat" pattern in which circumscribed cavities of free space within the matrix ("blobs") were joined to adjacent cavities by narrower throats of void space. For sufficiently small solutes, chains of blobs and throats traversed the matrix, providing pathways for trans-matrix permeation. The matrices showed threshold or gating properties with respect to permeation: solutes whose radius exceeded a critical value, at which a throat on the last connected trans-matrix pathway pinched off, could not cross, whereas smaller solutes had nonzero permeability. The thresholds may give the glomerular fiber matrix porelike response properties and explain why pore models have been such a useful means of treating permselectivity.

Capillaries↗
PubMed1989

Role of Norwalk virus in two foodborne outbreaks of gastroenteritis: definitive virus association.

Two separate food-associated outbreaks of gastroenteritis occurred among Erie County, New York residents in June 1986. In one outbreak, cases of illness were estimated to have occurred in 50% of the approximately 700 persons in 13 groups who ate at an out-of-county restaurant during a seven-day period, and, in the second outbreak, illness occurred in 26 (30%) of 87 persons who attended a graduation party held in a private home. Laboratory investigation included serology (blocking radioimmunoassay) to determine seroconversion to Norwalk virus and an enzyme immunoassay for detection of Norwalk virus antigen in stools, which the investigators have found to be more specific for Norwalk virus than serology. Seroconversion to Norwalk virus occurred in 11 (79%) of 14 restaurant-related cases and seven (100%) of seven graduation party cases. Seroconversion to Norwalk virus antigen was also found in four (40%) of 10 food handlers at the restaurant and in two (100%) of two food handlers at the graduation party. Antigen was detected in the stools of three (20%) of 15 restaurant-related cases and four (67%) of six graduation party cases. No stools for viral analyses were available for testing from food handlers. All seven of the patients with Norwalk virus-positive stools were also positive by seroconversion. Widespread availability of reagents for stool antigen detection would result in confirmation of more outbreaks due to Norwalk virus and in a more timely manner.

Disease Outbreaks↗
PubMed1985

Uptake of iron from hemoglobin and the haptoglobin-hemoglobin complex by hemolytic bacteria.

The abilities of Staphylococcus aureus and Streptococcus pyogenes to remove iron from mouse 59Fe hemoglobin that was either in free form or complexed with human haptoglobin, were evaluated. 59Fe hemoglobin from the amphibian Taricha granulosa was also used in free form or complexed with the amphibian's hemoglobin-binding proteins. Contrary to what was reported from a study using pathogenic Escherichia coli, haptoglobin failed to exhibit a bacteriostatic influence when complexed with hemoglobin. In our study, more 59Fe was removed by the bacteria from the haptoglobin-hemoglobin complex than from free mouse hemoglobin. The hemoglobin and hemoglobin-plasma protein complexes of Taricha were stripped of 59Fe at similar rates and extents by both bacterial species.

Amphibians↗
PubMedDate not supplied

[Inflammatory bowel disease in childhood].

Inflammatory bowel disease in childhood is becoming increasingly important as a result of a marked increase in incidence occurring over the past 20 years. In Crohn's disease the onset is commonly insidious, with symptoms such as growth failure, which do not immediately suggest intestinal disease. This may result in a correct diagnosis being delayed for several years. The role of paediatric colonoscopy is discussed, together with the macroscopic and microscopic appearances of the lesions. The indications and efficacy of drug therapy in Crohn's disease and ulcerative colitis are outlined and the importance of nutritional support, particularly in children with growth failure, is discussed. The indications for surgery are summarised and the need for a multidisciplinary approach, particularly in cases of fulminating colitis where early surgery is indicated, is emphasised. Most children with inflammatory bowel disease do reasonably well and even those children undergoing proctocolectomy adapt to a stoma provided they receive optimal psycho-social preparation and support.

Child↗