Browsing by Subject "beta-Galactosidase"

Now showing 1 - 3 of 3

Open Access
Classification and genetic characterization of pattern-forming Bacilli.
(Mol Microbiol, 1998-02) Rudner, R; Martsinkevich, O; Leung, W; Jarvis, ED
One of the more natural but less commonly studied forms of colonial bacterial growth is pattern formation. This type of growth is characterized by bacterial populations behaving in an organized manner to generate readily identifiable geometric and predictable morphologies on solid and semi-solid surfaces. In our first attempt to study the molecular basis of pattern formation in Bacillus subtilis, we stumbled upon an enigma: some strains used to describe pattern formation in B. subtilis did not have the phenotypic or genotypic characteristics of B. subtilis. In this report, we show that these strains are actually not B. subtilis, but belong to a different class of Bacilli, group I. We show further that commonly used laboratory strains of B. subtilis can co-exist as mixed cultures with group I Bacilli, and that the latter go unnoticed when grown on frequently used laboratory substrates. However, when B. subtilis is grown under more stringent semiarid conditions, members of group I emerge in the form of complex patterns. When B. subtilis is grown under less stringent and more motile conditions, B. subtilis forms its own pattern, and members of group I remain unnoticed. These findings have led us to revise some of the mechanistic and evolutionary hypotheses that have been proposed to explain pattern growth in Bacilli.
Open Access
Intracoronary adenovirus-mediated delivery and overexpression of the beta(2)-adrenergic receptor in the heart : prospects for molecular ventricular assistance.
(Circulation, 2000-02-01) Glower, Donald D Jr; Hata, Jonathan Andrew; Koch, Walter J; Kypson, Alan P; Lefkowitz, Robert J; Lilly, R Eric; Pippen, Anne; Shah, AS; Silvestry, Scott Christopher; Tai, Oliver
BACKGROUND: Genetic modulation of ventricular function may offer a novel therapeutic strategy for patients with congestive heart failure. Myocardial overexpression of beta(2)-adrenergic receptors (beta(2)ARs) has been shown to enhance contractility in transgenic mice and reverse signaling abnormalities found in failing cardiomyocytes in culture. In this study, we sought to determine the feasibility and in vivo consequences of delivering an adenovirus containing the human beta(2)AR cDNA to ventricular myocardium via catheter-mediated subselective intracoronary delivery. METHODS AND RESULTS: Rabbits underwent percutaneous subselective catheterization of either the left or right coronary artery and infusion of adenoviral vectors containing either a marker transgene (Adeno-betaGal) or the beta(2)AR (Adeno-beta(2)AR). Ventricular function was assessed before catheterization and 3 to 6 days after gene delivery. Both left circumflex- and right coronary artery-mediated delivery of Adeno-beta(2)AR resulted in approximately 10-fold overexpression in a chamber-specific manner. Delivery of Adeno-betaGal did not alter in vivo left ventricular (LV) systolic function, whereas overexpression of beta(2)ARs in the LV improved global LV contractility, as measured by dP/dt(max), at baseline and in response to isoproterenol at both 3 and 6 days after gene delivery. CONCLUSIONS: Percutaneous adenovirus-mediated intracoronary delivery of a potentially therapeutic transgene is feasible, and acute global LV function can be enhanced by LV-specific overexpression of the beta(2)AR. Thus, genetic modulation to enhance the function of the heart may represent a novel therapeutic strategy for congestive heart failure and can be viewed as molecular ventricular assistance.
Open Access
PEDF Deletion Induces Senescence and Defects in Phagocytosis in the RPE.
(International journal of molecular sciences, 2022-07) Rebustini, Ivan T; Crawford, Susan E; Becerra, S Patricia
The retinal pigment epithelium (RPE) expresses the Serpinf1 gene to produce pigment epithelium-derived factor (PEDF), a retinoprotective protein that is downregulated with cell senescence, aging and retinal degenerations. We determined the expression of senescence-associated genes in the RPE of 3-month-old mice that lack the Serpinf1 gene and found that Serpinf1 deletion induced H2ax for histone H2AX protein, Cdkn1a for p21 protein, and Glb1 gene for β-galactosidase. Senescence-associated β-galactosidase activity increased in the Serpinf1 null RPE when compared with wild-type RPE. We evaluated the subcellular morphology of the RPE and found that ablation of Serpinf1 increased the volume of the nuclei and the nucleoli number of RPE cells, implying chromatin reorganization. Given that the RPE phagocytic function declines with aging, we assessed the expression of the Pnpla2 gene, which is required for the degradation of photoreceptor outer segments by the RPE. We found that both the Pnpla2 gene and its protein PEDF-R declined with the Serpinf1 gene ablation. Moreover, we determined the levels of phagocytosed rhodopsin and lipids in the RPE of the Serpinf1 null mice. The RPE of the Serpinf1 null mice accumulated rhodopsin and lipids compared to littermate controls, implying an association of PEDF deficiency with RPE phagocytosis dysfunction. Our findings establish PEDF loss as a cause of senescence-like changes in the RPE, highlighting PEDF as both a retinoprotective and a regulatory protein of aging-like changes associated with defective degradation of the photoreceptor outer segment in the RPE.