Eligible persons with HIV infection can receive client-centered case management to coordinate medical and social services. Novel mobile health interventions could improve effective case management and retention in care, an important goal to help end the HIV epidemic. Using a hybrid type I effectiveness-implementation design, we assessed whether access to bidirectional, free-draft secure text messaging with a case manager and clinic pharmacist could improve client satisfaction and care retention in a Southern academic HIV clinic.
View Article and Find Full Text PDFRadiometric calibration of laser-based, topographic lidar sensors that measure range via time of flight or phase difference is well established. However, inexpensive, short-range lidar sensors that utilize non-traditional ranging techniques, such as indirect time of flight, may report radiometric quantities that are not appropriate for existing calibration methods. One such lidar sensor is the TeraRanger Evo 60 m by Terabee, whose reported amplitude measurements do not vary smoothly with the amount of return signal power.
View Article and Find Full Text PDFBetween 2006 and 2013, we salvaged and necropsied 362 seabird specimens from Tern Island, French Frigate Shoals, Northwestern Hawaiian Islands. Plastic ingestion occurred in 11 of the 16 species sampled (68.75%), representing four orders, seven families, and five foraging guilds: four plunge-divers, two albatrosses, two nocturnal-foraging petrels, two tuna-birds, and one frigatebird.
View Article and Find Full Text PDFIxotrophy is a process that enables certain microbes to prey on other cells. The ability of cells to aggregate or adhere is thought to be a significant initial step in ixotrophy. The gliding, multicellular filamentous bacterium Aureispira sp.
View Article and Find Full Text PDFMyxococcus xanthus undergoes phase variation during growth to produce predominantly two colony phenotypes. The majority are yellow colonies containing swarm-proficient cells and a minority are tan colonies containing swarm-deficient cells. Comparison of the transcriptomes of a yellow variant, a tan variant, and three tan mutants led to the identification of differentially-regulated genes that define key segments of the phase variation pathway.
View Article and Find Full Text PDFTerrestrial laser scanners are sophisticated instruments that operate much like high-speed total stations. It has previously been shown that unmodelled systematic errors can exist in modern terrestrial laser scanners that deteriorate their geometric measurement precision and accuracy. Typically, signalised targets are used in point-based self-calibrations to identify and model the systematic errors.
View Article and Find Full Text PDFGliding motility is critical for normal development of spore-filled fruiting bodies in the soil bacterium Myxococcus xanthus. Mutations in mgl block motility and development but one mgl allele can be suppressed by a mutation in masK, the last gene in an operon adjacent to the mgl operon. Deletion of the entire 5.
View Article and Find Full Text PDFMyxococcus xanthus can vary its phenotype or 'phase' to produce colonies that contain predominantly yellow or tan cells that differ greatly in their abilities to swarm, survive and develop. Yellow variants are proficient at swarming (++) and tend to lyse in liquid during stationary phase. In contrast, tan variants are deficient in swarming (+) and persist beyond stationary phase.
View Article and Find Full Text PDFBackground: The mglA gene from the bacterium Myxococcus xanthus encodes a 22kDa protein related to the Ras superfamily of monomeric GTPases. MglA is required for the normal function of A-motility (adventurous), S-motility (social), fruiting body morphogenesis, and sporulation. MglA and its homologs differ from all eukaryotic and other prokaryotic GTPases because they have a threonine (Thr78) in place of the highly conserved aspartate residue of the consensus PM3 (phosphate-magnesium binding) region.
View Article and Find Full Text PDFAssessing the biodiversity of macroinvertebrate fauna in freshwater ecosystems is an essential component of both basic ecological inquiry and applied ecological assessments. Aspects of taxonomic diversity and composition in freshwater communities are widely used to quantify water quality and measure the efficacy of remediation and restoration efforts. The accuracy and precision of biodiversity assessments based on standard morphological identifications are often limited by taxonomic resolution and sample size.
View Article and Find Full Text PDFMglA, a 22-kDa protein related to monomeric GTPases, is required for the normal operation of the A (Adventurous) and S (Social) motility and for multicellular development of Myxococcus xanthus. To determine how MglA controls A- and S-motility, MglA was assayed biochemically and its cellular location was determined. His-tagged MglA hydrolyzed GTP slowly in vitro at a rate nearly identical to that of Ras showing that MglA has GTPase activity.
View Article and Find Full Text PDFThe bacterium Myxococcus xanthus glides over surfaces using two different locomotive mechanisms, called S (social) and A (adventurous) motility that enable cells to move both as groups and as individuals. Neither mechanism involves flagella. The functions of these two motors are coordinated by the activity of a small Ras-like protein, encoded by the mglA gene.
View Article and Find Full Text PDFThe bacterium Myxococcus xanthus has two motility systems: S motility, which is powered by type IV pilus retraction, and A motility, which is powered by unknown mechanism(s). We found that A motility involved transient adhesion complexes that remained at fixed positions relative to the substratum as cells moved forward. Complexes assembled at leading cell poles and dispersed at the rear of the cells.
View Article and Find Full Text PDFMyxococcus xanthus has two different mechanisms of motility, adventurous (A) motility, which permits individual cells to glide over solid surfaces, and social (S) motility, which permits groups of cells to glide. To identify the genes involved in S-gliding motility, we mutagenized a delta aglU (A-) strain with the defective transposon, magellan-4, and screened for S- mutants that form nonmotile colonies. Sequence analysis of the sites of the magellan-4 insertions in these mutants and the alignment of these sites with the M.
View Article and Find Full Text PDFMembers of the genus Archaeoglobus are hyperthermophilic sulfate reducers with an optimal growth temperature of 83 degrees C. Archaeoglobus fulgidus can utilize simple compounds including D-lactate, L-lactate and pyruvate as the sole substrate for carbon and electrons for dissimilatory sulfate reduction. Previously we showed that this organism makes a D-lactate dehydrogenase (Dld) that requires FAD and Zn2+ for activity.
View Article and Find Full Text PDFThe aglZ gene of Myxococcus xanthus was identified from a yeast two-hybrid assay in which MglA was used as bait. MglA is a 22-kDa cytoplasmic GTPase required for both adventurous and social gliding motility and sporulation. Genetic studies showed that aglZ is part of the A motility system, because disruption or deletion of aglZ abolished movement of isolated cells and aglZ sglK double mutants were nonmotile.
View Article and Find Full Text PDFMyxococcus xanthus glides over solid surfaces without the use of flagella, dependent upon two large sets of adventurous (A) and social (S) genes, using two different mechanisms of gliding motility. Myxococcus xanthus A-S- double mutants form non-motile colonies lacking migratory cells at their edges. We have isolated 115 independent mutants of M.
View Article and Find Full Text PDFThe mglA gene encodes a 22 kDa GTPase that is critical for single-cell (A) gliding, type IV pili-mediated (S) gliding and development of Myxococcus xanthus. To identify components that interact with MglA to control these processes, second-site mutations that restore movement to non-motile mglA mutants were sought. An allele-specific extragenic suppressor of mglA8, named mas815 (mglA8 suppressor 15), was obtained.
View Article and Find Full Text PDFAn enzyme exhibiting NADH oxidase (diaphorase) activity was isolated from the hyperthermophilic sulfate-reducing anaerobe Archaeoglobus fulgidus. N-terminal sequence of the protein indicates that it is coded for by open reading frame AF0395 in the A. fulgidus genome.
View Article and Find Full Text PDFMol Microbiol
October 2001
A gene encoding a homologue of the Escherichia coli GidA protein (glucose-inhibited division protein A) lies immediately upstream of aglU, a gene encoding a WD-repeat protein required for motility and development in Myxococcus xanthus. The GidA protein of M. xanthus shares about 48% identity overall with the small (approximately equal to 450 amino acid) form of GidA from eubacteria and about 24% identity overall with the large (approximately equal to 620 amino acid) form of GidA from eubacteria and eukaryotes.
View Article and Find Full Text PDFThe aglU gene of Myxococcus xanthus encodes a protein similar to Het-E1 (vegetative incompatibility) from Podospora anserina, acylaminoacyl-peptidase from Bacillus subtilis, and TolB from Escherichia coli. These proteins all have evenly spaced SPDG repeats that are characteristic of a larger motif called the WD-repeat. The WD-repeat is predicted to form a beta-propeller structure that mediates the assembly of heteromeric protein complexes.
View Article and Find Full Text PDFJ Bacteriol
December 1999
Archaeoglobus fulgidus, a hyperthermophilic, archaeal sulfate reducer, is one of the few organisms that can utilize D-lactate as a sole source for both carbon and electrons. The A. fulgidus open reading frame, AF0394, which is predicted to encode a D-(-)-lactate dehydrogenase (Dld), was cloned, and its product was expressed in Escherichia coli as a fusion with the maltose binding protein (MBP).
View Article and Find Full Text PDFPlasmids with the aadA gene from plasmid R100, which confers resistance to the aminoglycosides spectinomycin and streptomycin in Escherchia coli, can be introduced into wild-type Myxococcus xanthus, strain DK1622, by electroporation. Recombinant M. xanthus strains with integrated plasmids carrying the aadA gene acquire resistance to high levels of these antibiotics.
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