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University of Massachusetts Medical School

Cellular and Molecular Physiology

Microbiology and Physiological Systems Publications and Presentations

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Full-Text Articles in Life Sciences

Direct Visualization Of Hiv-1 Replication Intermediates Shows That Capsid And Cpsf6 Modulate Hiv-1 Intra-Nuclear Invasion And Integration, Christopher R. Chin, Jill Perreira, George Savidis, Jocelyn M. Portmann, Aaron M. Aker, Eric M. Feeley, Miles C. Smith, Abraham L. Brass Nov 2015

Direct Visualization Of Hiv-1 Replication Intermediates Shows That Capsid And Cpsf6 Modulate Hiv-1 Intra-Nuclear Invasion And Integration, Christopher R. Chin, Jill Perreira, George Savidis, Jocelyn M. Portmann, Aaron M. Aker, Eric M. Feeley, Miles C. Smith, Abraham L. Brass

Microbiology and Physiological Systems Publications and Presentations

Direct visualization of HIV-1 replication would improve our understanding of the viral life cycle. We adapted established technology and reagents to develop an imaging approach, ViewHIV, which allows evaluation of early HIV-1 replication intermediates, from reverse transcription to integration. These methods permit the simultaneous evaluation of both the capsid protein (CA) and viral DNA genome (vDNA) components of HIV-1 in both the cytosol and nuclei of single cells. ViewHIV is relatively rapid, uses readily available reagents in combination with standard confocal microscopy, and can be done with virtually any HIV-1 strain and permissive cell lines or primary cells. Using ViewHIV ...


A Novel Membrane Protein Influencing Cell Shape And Multicellular Swarming Of Proteus Mirabilis, Nicole A. Hay, Donald J. Tipper, Daniel Gygi, Colin Hughes Apr 1999

A Novel Membrane Protein Influencing Cell Shape And Multicellular Swarming Of Proteus Mirabilis, Nicole A. Hay, Donald J. Tipper, Daniel Gygi, Colin Hughes

Microbiology and Physiological Systems Publications and Presentations

Swarming in Proteus mirabilis is characterized by the coordinated surface migration of multicellular rafts of highly elongated, hyperflagellated swarm cells. We describe a transposon mutant, MNS185, that was unable to swarm even though vegetative cells retained normal motility and the ability to differentiate into swarm cells. However, these elongated cells were irregularly curved and had variable diameters, suggesting that the migration defect results from the inability of these deformed swarm cells to align into multicellular rafts. The transposon was inserted at codon 196 of a 228-codon gene that lacks recognizable homologs. Multiple copies of the wild-type gene, called ccmA, for ...


A Nonswarming Mutant Of Proteus Mirabilis Lacks The Lrp Global Transcriptional Regulator, Nicole A. Hay, Donald J. Tipper, Daniel Gygi, Colin Hughes Aug 1997

A Nonswarming Mutant Of Proteus Mirabilis Lacks The Lrp Global Transcriptional Regulator, Nicole A. Hay, Donald J. Tipper, Daniel Gygi, Colin Hughes

Microbiology and Physiological Systems Publications and Presentations

Proteus swarming is the rapid cyclical population migration across surfaces by elongated cells that hyperexpress flagellar and virulence genes. The mini-Tn5 transposon mutant mns2 was isolated as a tight nonswarming mutant that did not elongate or upregulate flagellar and hemolysin genes. Individual cell motility was retained but was reduced. The transposon had inserted in the gene encoding the global transcriptional regulator Lrp (leucine-responsive regulatory protein), expression of which was upregulated in differentiating swarm cells. Swarming was restored to the lrp mutant by artificial overexpression of the flhDC flagellar regulatory master operon. Lrp may be a key component in generating or ...


Secretion Of Saccharomyces Cerevisiae Killer Toxin: Processing Of The Glycosylated Precursor, H. Bussey, D. Saville, D. Greene, Donald J. Tipper, Keith A. Bostian Aug 1983

Secretion Of Saccharomyces Cerevisiae Killer Toxin: Processing Of The Glycosylated Precursor, H. Bussey, D. Saville, D. Greene, Donald J. Tipper, Keith A. Bostian

Microbiology and Physiological Systems Publications and Presentations

Killer toxin secretion was blocked at the restrictive temperature in Saccharomyces cerevisiae sec mutants with conditional defects in the S. cerevisiae secretory pathway leading to accumulation of endoplasmic reticulum (sec18), Golgi (sec7), or secretory vesicles (sec1). A 43,000-molecular-weight (43K) glycosylated protoxin was found by pulse-labeling in all sec mutants at the restrictive temperature. In sec18 the protoxin was stable after a chase; but in sec7 and sec1 the protoxin was unstable, and in sec1 11K toxin was detected in cell lysates. The chymotrypsin inhibitor tosyl-l-phenylalanyl chloromethyl ketone (TPCK) blocked toxin secretion in vivo in wild-type cells by inhibiting protoxin ...


Coat Protein Synthesis During Sporulation Of Bacillus Subtilis: Immunological Detection Of Soluble Precursors To The 12,200-Dalton Spore Coat Protein, Robert C. Goldman, Donald J. Tipper Sep 1981

Coat Protein Synthesis During Sporulation Of Bacillus Subtilis: Immunological Detection Of Soluble Precursors To The 12,200-Dalton Spore Coat Protein, Robert C. Goldman, Donald J. Tipper

Microbiology and Physiological Systems Publications and Presentations

Antibody specific to the 12,200-dalton spore coat protein of Bacillus subtilis was used to detect the synthesis of cross-reacting material during sporulation. Cross-reacting protein was first detected by immunoprecipitation after 4 h of development and represented at least 1 to 2% of the total soluble protein synthesis at 5.5 h. A polypeptide of 21,000 daltons was detected in immunoprecipitates by gel electrophoresis. This polypeptide did not accumulate in sporulating cells and was rapidly turned over at the time of coat deposition. In contrast, a 32,000-dalton polypeptide reacted with antibody when unlabeled cell protein was denatured with ...