Effects of non-MHC loci on resistance to retrovirus-induced immunodeficiency in mice

Mice of certain strains are highly sensitive to development of a severe immunodeficiency disease following inoculation as adults with LP-BM5 murine leukemia viruses (MuLV) whereas others are extremely resistant. These strain-dependent differences in response to infection have been shown to be genetically determined with resistance to disease being, in general, associated with homozygosity for Fv-1 ⁿand H-2 haplotypes a and d and sensitivity with homozygosity for Fv-1 ^band other H-2 haplotypes including b, s, and q. The Fv-1 ^b, H-2 ^rstrain RIIIS/J (RIIIS) was found to be highly resistant to disease even though B10.RIII(71NS)/J (B10.RIII), also H-2 ^r, was very sensitive, thus excluding a role for H-2 in the resistance of RIIIS. The characteristics of RIIIS resistance were evaluated in studies of infected (B10.RIII×RIIIS) F₁, F₂ and reciprocal backcross mice. Resistance to disease was shown to be semidominant and determined by more than one gene, although a preponderant influence of a single gene was suggested. Studies of segregating populations showed that resistance was not associated with or linked to polymorphisms of the V _\complex or genes in proximity to the Emv-2 locus on chromosome 8. However, there was almost complete concordance between absence of disease in infected mice and inhibition of ecotropic virus spread. These results demonstrate that genes other than Fv-1 or H-2 can profoundly influence the development of retrovirus-induced immunodeficiency and replication of ecotropic viruses.Abbreviations MuLV murine leukemia virus - MCF mink cell focus-inducing MuLV - B6 C57BL/6 - BM5d the defective virus in LP-BM5 MuLV - MAIDS murine acquired immunodeficiency syndrome - RIIIS RIIIS/J - B10.RIII B10.RIII (71NS)/J - MLR mixed lymphocyte reaction - FACS fluorescence activated cell sorter     

Immunochemical characterisation of parathyroid hormone-related protein from tumor and non-tumor cells

The molecular forms of parathyroid hormone-related protein (PTHRP) in conditioned media from the BEN human lung cancer cell line, rat parathyroid cells (PT-r) and human keratinocytes were studied by gel-filtraton chromatography with assay of PTHRP by immunoassays and bioassay. Immunoreactivity (1–86 and 1–34) and bioactivity (1–34) in conditioned media eluted as a coincident major peak (approx. molecular mass 19–22 kDa) and there was evidence of amino-terminal species in the molecular mass range 10–16 kDa in BEN and keratinocyte media. Western blotting of PTHRP affinity purified by monoclonal antibodies directed at regions 1–34 or 37–67, identified a major species in all cell cytosols and media with an apparent molecular mass of 24–25 kDa, consistently slighty larger than recombinant PTHRP(1–141) (mobility of 21 kDa) which may represent an intact or native form of PTHRP. Additional amino-terminal species were identified in medium from keratinocytes (16 and 7 kDa), BEN cells (18 and 14 kDa) and PT-R cells (17 kDa), suggesting that processing occurs at the C-terminus and within the mid-region to form a range of amino-terminal fragments.     

Vicilin genes ofPisum

Summary We describe four genomic clones of pea 7S storage protein gene, one of which corresponds to convicilin, and the others to vicilin. Hybridization studies exploiting these clones, and previously identified cDNA clones, have enabled us to define six different loci. Three of these loci have been mapped to positions on chromosome 7.     

Genetic structure of natural populations of the red-spotted newt,Notophthalmus viridescens

Genetic variation is described at 15 loci in 2 neotenic and 12 nonneotenic populations of red-spotted newts. Though high levels of genetic similarity (I=0.990) were found among all populations, allele frequencies at six of the eight most polymorphic loci show significant heterogeneity across populations. Change in allele frequencies at two of these loci (Pep-2 and Ldh-1) is significantly correlated with latitude. Interspecific homologies are established for newt peptidases based on substrate specificities and lactate dehydrogenases based on tissue distribution, thermal stability, and kinetic properties. Nonneotenic populations are highly variable (H=0.157) and neotenic populations are only slightly, but significantly, less variable (H=0.120). The high levels of heterozygosity detected in nonneotenic populations may result from large effective population size and/or environmental heterogeneity. The unexpectedly high heterozygosity values obtained for the neotenic populations may indicate adult dispersal or the presence of some previously undetected red efts at these localities. In any case, a major change in life history has apparently had little effect on the genetic structure of these populations.This research was supported by grants from the Blakeslee Fund of Smith College.     

Cerebral Blood Flow and Oxidative Metabolism in Conscious Fischer-344 Rats of Different Ages

Abstract: The cerebral metabolic rates for O₂ and for glucose were measured in conscious, fasted male Fischer-344 rats at the ages of 3, 12, and 24 months, and cerebral blood flow was determined with ¹⁴C-iodoantipyrine. The metabolic rates for oxygen and glucose were obtained by multiplying blood flow by the O₂ and glucose concentration differences, respectively, between blood in the femoral artery and in the superior sagittal sinus. Mean cerebral blood flow and the metabolic rates for oxygen and glucose did not differ significantly (p > 0.05) between 3 and 12 or between 12 and 24 months. Nor did the arteriovenous differences for O₂ and for glucose change significantly with age. Because the superior sagittal sinus drains blood mainly from the cerebral cortex, the results indicate that average cerebral cortical oxidative metabolism, and the coupling ratios between the cerebral metabolic rate for oxygen and cerebral blood flow and between the cerebral metabolic rate for glucose and cerebral blood flow, do not change significantly with age in the Fischer-344 rat.     

Efficient extraction of RNA from mammalian tissue

RNA extraction from mammalian tissue has been compared using the different deproteinizing agents: a) guanidine-HCl, b) guanidinium-thiocyanate, c) buffer-saturated phenol, or d) buffer-saturated phenol followed by a proteinase K digestion of the aqueous phase. Both solid tissues (first, second, and third trimester fetal bovine pancreas), and human white blood cell populations were studied. Degradation, as seen in citric acid-urea agarose gels, and the ability to serve as templates for cell-free protein synthesis were used as criteria to assess the efficiency of the different methods. We conclude that employing buffer-saturated phenol with proteinase K digestion is a superior method for consistent extraction of relatively undegraded RNA in quantitative amounts from mammalian tissue.     

Elevated specific activity of 5′-nucleotidase in a spinal cord myelin fraction from shiverer mice comparison with other myelin-associated enzymes and myelin proteins

Meylin partially purified from spinal cords of dysmyelinating mutant (shiverer) mice had almost three-fold the specific activity of 5′-nucleotidase found in the respective myelin fraction from normal mice. The specific activities of two other normally myelin-associated enzymes, 2′,3′-cyclic nucleotide-3′-phosphohydrolase and carbonic anhydrase, were only slightly higher in the myelin membranes from shiveres, compared to those from controls. In the mutants, the three enzymes probably occur in oligodendrocyte processes. Hhypothetically, the 5′-nucleotidase in the myelin sheath in shiverer and normal mice may be localized in specialized structures.