Conservation of avian germplasm by xenogeneic transplantation of spermatogonia from sexually mature donors.

Approximately 12.5% of all 9,920 extant bird species in the world are threatened with extinction, and yet conservation efforts through natural breeding of captive species continue to encounter difficulties. However, sperm cryopreservation and artificial insemination offer potential benefits over natural breeding, but their applicability is still limited in nondomestic species.

Heterokaryotic nuclear conditions and a heterogeneous nuclear population are observed by flow cytometry in Phytophthora infestans.

A simple and reliable method for preparation of whole nuclei of a common oomycete, Phytophthora infestans, is described for laser flow cytometry. The ease of preparation, the absence of detectable debris and aggregates, and the precision in determinations of DNA content per nucleus improve interpretation and understanding of the genetics of the organism. Phytophthora infestans is the pathogen that causes potato and tomato late blight.

Natural glucocorticoids induce expansion of all developmental stages of murine bone marrow granulocytes without inhibiting function.

Natural glucocorticoids (Gc) produced during stress have profound effects on the immune system. It is well known that Gc induce apoptosis in precursor T and B cells, markedly altering lymphopoiesis. However, it has been noted that marrow myeloid cells expanded both in proportion and absolute numbers in the mouse after Gc exposure.

A role for leptin in sustaining lymphopoiesis and myelopoiesis.

Although leptin is known for its regulation of food intake, it has many emerging roles in immune function. To better define the role of leptin in hematopoietic processes, a leptin-deficient obese mouse (ob/ob) and C57BL/6 lean wild-type controls were compared. Despite their large size and consumption of substantial amounts of nutrients, the ob/ob mice had only 60% as many nucleated cells in their marrow as controls.

Chronic zinc deficiency in mice disrupted T cell lymphopoiesis and erythropoiesis while B cell lymphopoiesis and myelopoiesis were maintained.

Objective: The purpose of this study was to determine the impact of chronic zinc deficiency (ChrZD) on T and B cell lymphopoiesis, myelopoiesis and erythropoiesis in mice.

Methods: Young adult mice were fed a zinc adequate (ZA) or ChrZD synthetic diet for 34, 45, and 50 days. The cellular composition of the thymus and marrow were determined to assess the impact of ChrZD on lymphopoietic and hematopoietic processes using flow cytometry.

Reprogramming of the immune system during zinc deficiency.

Thymic atrophy, lymphopenia, and compromised cell- and antibody-mediated responses that cause increased rates of infections of longer duration are the immunological hallmarks of zinc deficiency (ZD) in humans and higher animals. As the deficiency advances, a reprogramming of the immune system occurs, beginning with the activation of the stress axis and chronic production of glucocorticoids that accelerate apoptosis among pre-B and -T cells. This reduces lymphopoiesis and causes atrophy of the thymus.

Alterations in cell membrane properties caused by perfluorinated compounds.

The recent detection of perfluorinated compounds (PFCs) in wildlife from even remote locations has spurred interest in the environmental occurrence and effects of these chemicals. While the global distribution of PFCs is increasingly understood, there is still little information available on their effects on wildlife. The amphiphillic nature of PFCs suggests that their effects could be primarily on cell membranes.

Differential induction of glucocorticoid-dependent apoptosis in murine lymphoid subpopulations in vivo following coexposure to lipopolysaccharide and vomitoxin (deoxynivalenol).

Lipopolysaccharide (LPS) and vomitoxin (VT) synergistically induce glucocorticoid- mediated apoptotic cell death in lymphoid tissues of the mouse. Based on the known effects of glucocorticoids, it was hypothesized that the combined exposure to LPS and VT targets immature lymphocyte populations. To test this hypothesis, we quantified the effects of VT and LPS on apoptosis induction in T lymphocyte subsets in thymus and B lymphocyte subsets in Peyer's patches and bone marrow.

Glucocorticoid-induced apoptosis in early B cells from human bone marrow.

The sensitivity of normal human lymphoid precursor cells to glucocorticoid-induced apoptosis is a subject of controversy. The in vitro response of cells of the B lineage (CD19(+)) from the marrow of 22 adult subjects to glucocorticoids was evaluated herein using both natural steroids and dexamethasone (Dex). When exposed to 1 micro M Dex, 32% of the subjects exhibited high losses of CD19(+) B cells in the range of 45%.

Endotoxin potentiation of trichothecene-induced lymphocyte apoptosis is mediated by up-regulation of glucocorticoids.

Exposure to bacterial endotoxin (lipopolysaccharide, LPS) is quite common and may increase human susceptibility to chemical-induced tissue injury. The purpose of this study was to identify mechanisms by which LPS potentiates lymphoid tissue depletion in B6C3F1 mice exposed to the common food-borne trichothecene mycotoxin, vomitoxin (VT). As demonstrated by DNA fragmentation and flow cytometric analysis, apoptosis in thymus, Peyer's patches, and bone marrow was marked in mice 12 h after administering Escherichia coli LPS (0.

Versatility of merocyanine 540 for the flow cytometric detection of apoptosis in human and murine cells.

Since apoptosis plays many roles in development, immune function, and disease, there is an ongoing need to identify inexpensive and reliable fluorochromes for the quantitation of apoptosis. Merocyanine 540 (MC540) binds to the outer membrane of cells and readily fluoresces in the highly disordered membranes of apoptotic cells making them readily detectable by flow cytometry. Protocols for the effective labeling and gating of MC540br apoptotic cells are provided.