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61.
62.
In all but the most sterile environments bacteria will reside in fluid being transported through conduits and some of these will attach and grow as biofilms on the conduit walls. The concentration and diversity of bacteria in the fluid at the point of delivery will be a mix of those when it entered the conduit and those that have become entrained into the flow due to seeding from biofilms. Examples include fluids through conduits such as drinking water pipe networks, endotracheal tubes, catheters and ventilation systems. Here we present two probabilistic models to describe changes in the composition of bulk fluid microbial communities as they are transported through a conduit whilst exposed to biofilm communities. The first (discrete) model simulates absolute numbers of individual cells, whereas the other (continuous) model simulates the relative abundance of taxa in the bulk fluid. The discrete model is founded on a birth-death process whereby the community changes one individual at a time and the numbers of cells in the system can vary. The continuous model is a stochastic differential equation derived from the discrete model and can also accommodate changes in the carrying capacity of the bulk fluid. These models provide a novel Lagrangian framework to investigate and predict the dynamics of migrating microbial communities. In this paper we compare the two models, discuss their merits, possible applications and present simulation results in the context of drinking water distribution systems. Our results provide novel insight into the effects of stochastic dynamics on the composition of non-stationary microbial communities that are exposed to biofilms and provides a new avenue for modelling microbial dynamics in systems where fluids are being transported. 相似文献
63.
Michael A. McClurkin Leah Rae Yingling Colby Ayers Rebecca Cooper-McCann Visakha Suresh Ann Nothwehr Debbie S. Barrington Tiffany M. Powell-Wiley 《PloS one》2015,10(11)
Background
Little is known about the association between cardiovascular (CV) health and health insurance status. We hypothesized that U.S. adults without health insurance coverage would have a lower likelihood of ideal cardiovascular health.Methods and Results
Using National Health and Nutrition Examination Survey (NHANES) data from 2007–2010, we examined the relationship between health insurance status and ideal CV health in U.S. adults aged ≥19 years and <65 (N = 3304). Ideal CV health was defined by the American Heart Association (AHA) as the absence of clinically manifested CV disease and the simultaneous presence of 6–7 “ideal” CV health factors and behaviors. Logistic regression modeling was used to determine the relationship between health insurance status and the odds of ideal CV health. Of the U.S. adult population, 5.4% attained ideal CV health, and 23.5% were without health insurance coverage. Those without health insurance coverage were more likely to be young (p<0.0001), male (p<0.0001), non-white (p<0.0001), with less than a high school degree (p<0.0001), have a poverty-to-income ratio less than 1 (p<0.0001) and unemployed (p<0.0001) compared to those with coverage. Lack of health insurance coverage was associated with a lower likelihood of ideal CV health; however, this relationship was attenuated by socioeconomic status.Conclusions
U.S. adults without health insurance coverage are less likely to have ideal CV health. Population-based strategies and interventions directed at the community-level may be one way to improve overall CV health and reach this at-risk group. 相似文献64.
Christina B. Madsen-Duggan John S. Debenham Thomas F. Walsh Lin Yan Pei Huo Junying Wang Xinchun Tong Julie Lao Tung M. Fong Jing Chen Xiao Cathy R.-R.C. Huang Chun-Pyn Shen D.Sloan Stribling Lauren P. Shearman Alison M. Strack Mark T. Goulet Jeffrey J. Hale 《Bioorganic & medicinal chemistry letters》2010,20(12):3750-3754
Synthesis and structure–activity relationships of cannabinoid-1 receptor (CB1R) inverse agonists based on dihydro-pyrano[2,3-b] pyridine and tetrahydro-1,8-naphtyridine scaffolds are presented. Rat food intake and pharmacokinetic evaluation of 13g, 13i, 13k and 17a revealed these compounds to be highly efficacious orally active modulators of CB1R. 相似文献
65.
Shaw R. Gargis Harry E. Heath Paul A. LeBlanc Linda Dekker Robin S. Simmonds Gary L. Sloan 《Applied and environmental microbiology》2010,76(20):6944-6946
Resistance to lysostaphin, a staphylolytic glycylglycine endopeptidase, is due to a FemABX-like immunity protein that inserts serines in place of some glycines in peptidoglycan cross bridges. These modifications inhibit both binding of the recombinant cell wall targeting domain and catalysis by the recombinant catalytic domain of lysostaphin.Lysostaphin is a glycylglycine endopeptidase produced by Staphylococcus simulans biovar staphylolyticus (18) that lyses susceptible staphylococci by hydrolyzing the polyglycine cross bridges in their cell wall peptidoglycans (3). The lysostaphin gene sequence was independently determined in 1987 by two groups (8, 13). BLAST analysis (1) of mature lysostaphin revealed two domains: an N-terminal catalytic domain (CAT), which is a member of the M23 family of zinc metalloendopeptidases, and a C-terminal cell wall targeting domain (CWT), which is a member of the SH3b domain family (Fig. (Fig.11 A).Open in a separate windowFIG. 1.(A) Schematic diagram of mature lysostaphin, the recombinant catalytic domain (rCAT) (lysostaphin residues 1 to 148), and the recombinant cell wall targeting domain (rCWT) (lysostaphin residues 149 to 246). The numbers represent the beginning and end of the domains, and the solid boxes indicate the N-terminal His6 tag of the recombinant proteins. (B) SDS-PAGE analysis of rCAT and rCWT purified by a nickel affinity column. Mobilities of molecular mass standards are given on the left side of the gel.The lysostaphin endopeptidase resistance gene (epr or lif) encodes a FemABX-like immunity protein that is located adjacent to the lysostaphin gene on the plasmid pACK1 in S. simulans bv. staphylolyticus (4, 7, 20). Members of the FemABX family of proteins are nonribosomal peptidyl transferases that are involved in the addition of cross bridge amino acids during peptidoglycan subunit synthesis in the cytoplasm (15). In S. simulans bv. staphylolyticus, the lysostaphin immunity protein inserts serines in place of some glycines during peptidoglycan synthesis, which provides resistance to lysostaphin (4, 20).Originally it was suggested that the incorporation of serines in these peptidoglycan cross bridges gave increased resistance to lysostaphin because of the inability of the enzyme to hydrolyze glycyl-serine or seryl-glycine bonds (4, 14, 16). Others later reported that the CWT specifically binds to the polyglycine cross bridges in staphylococci (6) and the binding of CWT to producer-strain cells was less than that to susceptible cells (2). However, the ability of the enzyme or its targeting domain to bind to purified peptidoglycans from staphylococci containing the lysostaphin resistance gene has not been determined. Therefore, we determined if the modification to staphylococcal peptidoglycan cross bridges made by the lysostaphin immunity protein affected the activity of the binding domain, the catalytic domain, or both. 相似文献
66.
Because small peptides are lost into the organic solvents used, it is virtually impossible to obtain the complete amino acid sequence of a small peptide using only an automated peptide sequencer of the spinning cup type. To overcome this problem we have extended peptides at the carboxy terminus by attachment to equine cytochrome c by a water soluble carbodiimide, relying on the acetylated N-terminus of the cytochrome to minimize its direct contribution to recovery of PTH-amino acids. The Model Peptide H-Leu-Trp-Met-Arg-phe-Ala-OH was used for most experiments. After reaction of 3H-peptide with cytochrome c, about one-third of the tritium counts migrated with cytochrome c during gel filtration. After attachment, the amino acid sequence of the hexapeptide was readily determined with a single cleavage Quadrol program in a Beckman 890B sequencer, whereas only the N-terminal residue was recovered without attachment. The repetitive yield after attachment was 95-96%, with 21-27+ overlap and an initial yield of 18-20%. Sequence data with other peptides illustrate applications and present limitations of our approach. 相似文献
67.
Kris Sloan 《Anthropology & education quarterly》2007,38(1):24-41
In this article, I offer a review of the ethnographic research that reports the effects of current accountability policies on minority youth. Included in this article are qualitative investigations that have significant field-based components, most especially direct observations at the classroom level. In this article, I demonstrate both the power and potential of ethnography to offer clearer, more detailed portraits of the varied ways that current accountability policies affect teachers of minority youth, the curriculum and pedagogy that minority youth experience, minority youth in general, and the schooling of minority youth. 相似文献
68.
Mathupala SP Colen CB Parajuli P Sloan AE 《Journal of bioenergetics and biomembranes》2007,39(1):73-77
Metabolic aberrations in the form of altered flux through key metabolic pathways are primary hallmarks of many malignant tumors.
Primarily the result of altered isozyme expression, these adaptations enhance the survival and proliferation of the tumor
at the expense of surrounding normal tissue. Consequently, they also expose a unique set of targets for tumor destruction
while sparing healthy tissues. Despite this fact, development of drugs to directly target such altered metabolic pathways
of malignant tumors has been under-investigated until recently. One such target is the ultimate step of glycolysis, which,
as expected, presents itself as a metabolic aberration in most malignant tumors. Termed “aerobic glycolysis” due to abnormal
conversion of pyruvic acid to lactic acid even under normoxia, the altered metabolism requires these tumors to rapidly efflux
lactic acid to the microenvironment in order to prevent poisoning themselves. Thus, exposed is a prime “choke-point” to target
these highly malignant, frequently chemo- and radio- resistant tumors. This review will focus on current outcomes in targeting
lactate efflux in such tumors using glioma as a model, an ongoing project in our laboratory for the past half-decade, as well
as supporting evidence from recent studies by others on targeting this “tail-end” of glycolysis in other tumor models. 相似文献
69.
Parker MF Barten DM Bergstrom CP Bronson JJ Corsa JA Deshpande MS Felsenstein KM Guss VL Hansel SB Johnson G Keavy DJ Lau WY Mock J Prasad CV Polson CT Sloan CP Smith DW Wallace OB Wang HH Williams A Zheng M 《Bioorganic & medicinal chemistry letters》2007,17(16):4432-4436
A series of N-alkylbenzenesulfonamides were developed from a high throughput screening hit. Classic and parallel synthesis strategies were employed to produce compounds with good in vitro and in vivo gamma-secretase activity. 相似文献
70.
Deskus JA Epperson JR Sloan CP Cipollina JA Dextraze P Qian-Cutrone J Gao Q Ma B Beno BR Mattson GK Molski TF Krause RG Taber MT Lodge NJ Mattson RJ 《Bioorganic & medicinal chemistry letters》2007,17(11):3099-3104
A series of indole tetrahydropyridine and indole cyclohexenylamines was prepared, and their binding affinities at the human serotonin transporter (SERT) were determined. In particular, a nitrile substituent at the C5 position of the indole ring gave potent SERT activity. The stereochemistry of the N,N-dimethylamine substituent was determined for the most potent indole cyclohexenylamine, 6a. The enantiomers of 6a were energy minimized and compared to other conformationally restricted SSRIs. Compound 6a was found to give a dose-response similar to the SSRI fluoxetine in microdialysis studies in rats. 相似文献