Prevalence of Klebsiella oxytoca in Anolis carolensis of Louisiana.

Klebsiella oxytoca is a gram-negative bacterium that can be found throughout the environment as well as on mucosal membranes of mammals including humans. This bacterium is responsible for a variety of infections in humans including nosocomial infections resulting in hospital outbreaks. Reptiles including snakes, tuataras, and turtles have been shown to harbor this bacterium, and previous studies have shown that pet reptiles are a potential source for dissemination of pathogenic bacteria.

Injury mechanism dictates contribution of bone marrow-derived cells to murine hepatic vascular regeneration.

Stem and progenitor cells derived from adult marrow have been shown to regenerate vascular cells in response to injury. However, it is unclear whether the type of injury dictates the contribution of such cells to neovascularization and which subpopulations of cells contribute to vascular regeneration. To address these questions, we determined the extent that hematopoietic stem cells (HSC) contributed to blood vessel formation in response to two types of liver injury, partial hepatectomy (PH) and toxin-induced injury.

Plasticity and tissue regenerative potential of bone marrow-derived cells.

Diverse in vivo studies have suggested that adult stem cells might have the ability to differentiate into cell types other than those of the tissues in which they reside or derive during embryonic development. This idea of stem cell "plasticity" has led investigators to hypothesize that, similar to embryonic stem cells, adult stem cells might have unlimited tissue regenerative potential in vivo, and therefore, broad and novel therapeutic applications. Since the beginning of these observations, our group has critically examined these exciting possibilities for mouse bone marrow-derived cells by taking advantage of well-characterized models of tissue regeneration, Cre/lox technology, and novel stem cell isolation protocols.

Differential mRNA processing in hematopoietic stem cells.

Hematopoietic stem cells (HSCs) maintain tissue homeostasis by rapidly responding to environmental changes. Although this function is well understood, the molecular mechanisms governing this characteristic are largely unknown. We used a sequenced-based strategy to explore the role of both transcriptional and post-transcriptional regulation in HSC biology.

Skeletal muscle fiber-specific green autofluorescence: potential for stem cell engraftment artifacts.

Adult stem cell research has lately been plagued by controversy regarding the possibility that some adult stem cells can engraft into nonautochthonous tissues. While most reports have observed some level of engraftment, the prevalence has varied in some cases by two orders of magnitude, suggesting that major technical variations may underlie these differences, possibly outweighing the biological basis of the observations. Here we describe bright green autofluorescence in a specific subset of skeletal muscle fibers that strongly resembles emission from green fluorescent protein (GFP).

Single hematopoietic stem cells generate skeletal muscle through myeloid intermediates.

Recent studies have shown that cells from the bone marrow can give rise to differentiated skeletal muscle fibers. However, the mechanisms and identities of the cell types involved have remained unknown, and the validity of the observation has been questioned. Here, we use transplantation of single CD45+ hematopoietic stem cells (HSCs) to demonstrate that the entire circulating myogenic activity in bone marrow is derived from HSCs and their hematopoietic progeny.

Altered phenotype and reduced function of muscle-derived hematopoietic stem cells.

Objective: Skeletal muscle-derived cells have the potential to repopulate the major peripheral blood lineages of lethally irradiated mice and thus behave like hematopoietic stem cells (HSC). We have recently shown that muscle cells with HSC activity (ms-HSC) express CD45 and Sca-1, suggesting a hematopoietic origin. Here we sought to clarify contradictions in the literature regarding the phenotype of ms-HSC and precisely define the hematopoietic origin of these cells.

Cells of the hepatic side population contribute to liver regeneration and can be replenished with bone marrow stem cells.

Background And Objectives: The aim of this study was to determine whether Hoechst effluxing side population cells isolated from murine liver represent hepatic stem cells, and to examine whether hepatic side population cells arise from bone marrow side population cells.

Design And Methods: Side population cells were isolated from murine liver by flow cytometry after Hoechst staining and injected directly into murine livers of animals pre-treated with the hepatotoxin 3,5 diethoxy carbonyl-1, 4-dihydrocollidine (DDC). Y-chromosome in situ hybridization was used to track donor cells in the livers.

Distinct progenitor populations in skeletal muscle are bone marrow derived and exhibit different cell fates during vascular regeneration.

Vascular progenitors were previously isolated from blood and bone marrow; herein, we define the presence, phenotype, potential, and origin of vascular progenitors resident within adult skeletal muscle. Two distinct populations of cells were simultaneously isolated from hindlimb muscle: the side population (SP) of highly purified hematopoietic stem cells and non-SP cells, which do not reconstitute blood. Muscle SP cells were found to be derived from, and replenished by, bone marrow SP cells; however, within the muscle environment, they were phenotypically distinct from marrow SP cells.

Stem cells: a minireview.

The identification of adult-derived stem cells which maintain plasticity throughout the course of a lifetime, has transformed the field of stem cell biology. Bone marrow derived hematopoietic stem cells (HSC) are the most well-characterized population of these multipotential cells. First identified for their ability to reconstitute blood lineages and rescue lethally irradiated hosts, these cells have also been shown to differentiate and integrate into skeletal muscle, cardiac myocytes, vascular endothelium, liver, and brain tissue.

Muscle-derived hematopoietic stem cells are hematopoietic in origin.

It has recently been shown that mononuclear cells from murine skeletal muscle contain the potential to repopulate all major peripheral blood lineages in lethally irradiated mice, but the origin of this activity is unknown. We have fractionated muscle cells on the basis of hematopoietic markers to show that the active population exclusively expresses the hematopoietic stem cell antigens Sca-1 and CD45. Muscle cells obtained from 6- to 8-week-old C57BL/6-CD45.