Localization of the porcine growth hormone gene to chromosome 12pl.2 p1–5

Summary
The gene encoding the porcine growth hormone (GH) has been localized to the q-arm of chromosome 12 using high-resolution R-banded chromosomes for in situ hybridization. We report here the localization of GH on the p-arm of this chromosome when using in situ hybridization on high-resolution G-banded chromosomes. Sequential Q- and R-banding show that this discrepancy is caused by a reversed orientation of chromosome 12 in the R-banded high-resolution karyotype published by Rønne et al. (1987) and the G-banded standard karyotype.     

The theoretical analysis of the process of RNA molecule self-assembly

The Kinetic approach to the problem of the RNA structure prediction based on the analysis of the molecule self-formation is proposed. Re-structurization that occurs during processing is described in terms of Markov processes. A new formalism designating nucleotides by complex numbers is proposed, leading to the complex unitary space of nucleic vectors. Properties of structure and transition matrices are discussed in relation to the analysis of RNA structural formation processes. The non-linear dynamic behavior of secondary structure transitions is analyzed. Soliton-like oscillations of RNA and DNA tertiary structures are predicted. The Monte-Carlo simulation of the RNA structure self-formation is used to calculate the ensemble of the secondary structures of the tRNA^Ala precursor from Bombix mori formed during processing.     

In utero bone marrow transplantation of fetal baboons with mismatched adult baboon marrow.

In utero bone marrow transplantation to fetuses offers the potential advantage of ameliorating the effects of genetic disorders by transplanting allogeneic hematopoietic stem cells into recipients who are immunoincompetent and require no preparative regimen. Therefore, we undertook studies to examine the feasibility of in utero bone marrow transplantation of unrelated allogeneic adult bone marrow into fetal baboons. Thirty-one baboon fetuses were transplanted between the ages of 60 and 160 days gestation (normal gestation, 182 days) with unrelated allogeneic adult bone marrow containing a different isozyme of glucose-phosphate isomerase (GPI). Approximately one third of the 80-day fetuses demonstrated engraftment 1 month after transplantation. Three of three of the initial chimeras died in utero 45 to 80 days after transplantation and the remaining chimeras lost their graft. Furthermore, 80-day fetal baboons were able to recognize donor cells, maternal cells, and other adult baboon peripheral blood cells in a mixed lymphocyte culture (MLC) reaction but still could engraft with allogeneic bone marrow. In contrast all nonchimeric animals survived to term. These data suggest that fetal transplantation of primates is feasible using techniques employed in these studies and that transplantation of younger fetuses who are immunocompetent should be attempted.     

Analysis of synaptonemal complexes in a heterozygous human male carrier of a reciprocal translocation involving an acrocentric chromosome: heterosynapsis without previous homosynapsis

Summary Silver-stained synaptonemal complexes in surface-spread pachytene nuclei from an oligospermic man, heterozygous for a reciprocal translocation involving an acrocentric chromosome, were analyzed by electron microscopy. Contrary to the classically expected configuration, nonhomologous pairing was observed with asymetrical association of the lateral elements of the nonhomologous arms of the quadrivalents. A possible role of heterosynapsis in germ cell conservation is discussed.     

Macrophage catabolism of lipid A is regulated by endotoxin stimulation

Lipopolysaccharide (LPS) is a Gram-negative bacterial glycolipid that is believed to cause, by virtue of its stimulatory actions on macrophages and other eukaryotic cells, the life-threatening symptoms associated with Gram-negative infections. Macrophages both respond to and catabolically deactivate LPS. The lipid A moiety of LPS is responsible for the stimulatory actions of LPS on macrophages. We have previously developed methods employing a radiolabeled bioactive lipid A precursor, 4'-32P-lipid IVA, to study the interaction of this class of lipids with animal cells (Hampton, R. Y., Golenbock, D. T., and Raetz, C. R. H. (1988). J. Biol. Chem. 263, 14802-14807). In the current work, we have examined the uptake and catabolism of 4'-32P-lipid IVA by the RAW 264.7 cell line in serum-containing medium at physiological temperatures and have studied the effect of LPS stimulation on the ability of these cells to catabolize lipid IVA. RAW 264.7 macrophage-like cells avidly take up 4'-32P-lipid IVA under cell culture conditions at nanomolar concentrations. Uptake of lipid IVA was accompanied by lysosomal dephosphorylation of a fraction of the lipid to yield 4'-monophosphoryl lipid IVA. Chemically generated 4'-monophosphoryl lipid IVA was found to be substantially less bioactive than lipid IVA in the RAW cell, indicating that this catabolic dephosphorylation results in detoxification. In uptake experiments of 3-4 h duration, all metabolism of lipid IVA is blocked by ligands of the macrophage scavenger receptor. In longer experiments (24 h), both scavenger receptor-dependent and -independent uptake are responsible for the lysosomal catabolism of lipid IVA. Preincubation of RAW 264.7 cells with LPS caused dose-dependent inhibition of lipid IVA dephosphorylation. Sufficient LPS stimulation resulted in essentially complete inhibition of lipid IVA catabolism in both short- and long-term uptake experiments. This effect occurred at physiologically relevant concentrations of LPS (IC50 less than 1 ng/ml), and our data indicate that LPS-induced blockade of lipid IVA catabolism was due to the resultant physiological stimulation of the cells, and not inhibition of dephosphorylation by competition for uptake or enzymatic sites or by simple sequestration of labeled lipid IVA by LPS aggregates. We suggest that in the macrophage, LPS can modulate its own catabolism by virtue of its pharmacological properties. This effect of LPS could play a role in LPS pathophysiology as well as in macrophage biology.