The anal sac secretion of the red fox (Vulpes vulpes); its chemistry and microbiology. A comparison with the anal sac secretion of the lion (Panthera leo)

Phenylacetic, 3-phenylpropionic, $\text{p}$-hydroxyphenylacetic and 3 ($\text{p}$-hydroxyphenyl) propionic acids together with the series of C₂ to C₆ saturated fatty acids previously reported in the anal sac secretion of the red fox ($\text{Vulpes vulpes}$) are identified as constituents of the anal sac secretion of the lion (Panthera leo). All these compounds are also observed in the anal sac secretion of the red fox using gas chromatography. The aerobic microflora of red fox and domestic dog ($\text{Canis familiaris}$) anal sac secretion samples invariably consisted predominantly of $\text{Streptococcus faecium}$ and $\text{Streptococcus faecalis}$. The hypothesis that the secretion volatiles so far identified may be microbiologically produced is examined.     

Effect of varying glycerol and sucrose concentration combinations on embryo survival rate in a one-step cryoprotectant removal from frozen-thawed ovine embryos

Two hundred fifty-one ovine embryos were frozen in different levels of glycerol (1.0, 1.4, 2.0 or 2.8M) and thawed into one of four sucrose levels (0, 0.25, 1.0 or 2.0M) to determine the optimal glycerol-sucrose combination for one-step, in-straw thawing. Sucrose was toxic at low glycerol levels and mandatory at high levels. The 1.0M sucrose level with either 1.4 or 2.0M glycerol was optimal for one-step cryoprotectant removal.     

The malmö polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms

A mouse monoclonal antibody (MAB 9.9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism—Thr:Ala—at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148^thr) are designated Malmö A, and negative reactors (148^ala) are designated Malmö B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmö A in AB women is approximately half that of AA women, and “lyonization” is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over—including double crossing-over—appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ～50% of the AB women in the pool of Malmö A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmö epitope if the studies were limited to men.     

Analysis of a large nontranscribed spacer in the ribosomal DNA of the house cricket,Acheta domesticus (Orthoptera:Gryllidae)

An analysis of a 29-kilobase nontranscribed spacer fragment in the ribosomal DNA (rDNA) of the house cricket, Acheta domesticus, revealed a highly repetitious structure. A total of eight EcoRI repeats of three different size classes measuring 259, 420, and 508 base pairs (bp) was mapped to a region 2 kilobases (kb) from the 18 S coding region. The repeats were oriented in a nonrandom manner and had sequences homologous to DNA located immediately adjacent to the repetitive array. DNA sequence analysis showed that the repetitive region was composed of smaller direct repeats 66, 67, and 383 bp in length. There was minor length heterogeneity of the chromosomal restriction fragments containing the entire array, indicating that a variable number of EcoRI repeats is a minor contributor to the total repeat-unit length heterogeneity. Immediately upstream from the EcoRI array there is a 17-kb region composed of 50 to 60 subrepeat elements recognized by a variety of restriction endonucleases. A subcloned SmaI repeat from the array was not homologous to any other part of the rDNA repeat unit or other chromosomal DNA. There was little length heterogeneity in restriction fragments containing the chromosomal 17-kb repetitions region. Immediately upstream from the 17-Kb region there is a 4.1-kb segment with sequences homologous to the EcoRI repeats.     

Metastatic phenotype of human prostate tumor cells in athymic nude mice: Alteration by exposure to ethyl methanesulfonate and “reversion” by 5-azacytidine

Summary The human prostate tumor subline 1-LN-PC-3-1A (1-LN) is reproducibly metastatic in adult athymic nude mice. Cells surviving a brief in vitro exposure to ethyl methanesulfonate (EMS) exhibited a profound decrease in capacity for experimental lung metastasis in nude mice. Thirty days after EMS treatment, 1×10⁶ uncloned EMS-treated 1-LN cells (1-LN-EMS-10) were injected IV into groups of 6 to 8-week-old male athymic nude mice (BALB/cAnBOM). A median of 8.5 colonies/lung was observed among 20 1-LN-EMS-10-injected mice, which was significantly different from the median of 51 colonies/lung produced among 14 1-LN-injected mice (P=0.0002). This altered phenotype remained stable during 150 days of continuous culture. However, the 1-LN-EMS-10 cells were tumorigenic in 10/10 nude mice injected SC. Single lung tumor colonies recovered from 1-LN-EMS-10-injected mice and reinjected IV into nude mice produced medians of 32–63 colonies/lung. The altered metastatic phenotype resulting from treatment of 1-LN with EMS was reversed by exposure to a noncytotoxic dose of 5-azacytidine, but unaffected by a second exposure to EMS. Collectively these data demonstrate that the metastatic phenotype of these human tumor cells in athymic nude mice can be heritably altered by in vitro exposure to EMS and 5-azacytidine. Analysis of the mechanisms underlying these phenotypic changes may provide insight into parts of the complex process of tumor cell evolution.     

Characterization of the receptor for tumor necrosis factor (TNF) and lymphotoxin (LT) on human T lymphocytes. TNF and LT differ in their receptor binding properties and the induction of MHC class I proteins on a human CD4+ T cell hybridoma

TNF-alpha and lymphotoxin (LT or TNF-beta) are structurally related cytokines that share several proinflammatory and immunomodulatory activities. The shared biologic activities of TNF and LT have been attributed to their binding to a common cell surface receptor(s). We observed that rTNF enhanced the expression of MHC class I proteins on the human T cell hybridoma, II-23.D7, however LT was largely unable to regulate MHC expression. To determine the molecular basis of this disparity between LT and TNF the receptor binding characteristics of rTNF and rLT were investigated by direct and competitive radioligand assays on the II-23.D7 T hybridoma, and for comparison, anti-CD3 activated human T lymphocytes. Specific 125I-rTNF binding to the II-23.D7 line revealed a single class of sites with a Kd = 175 pM and 3000 sites/cell; anti-CD3 activated T cells exhibited specific TNF binding with similar properties. The relationship of receptor occupancy to the induction of MHC class I Ag yielded a hyperbolic curve indicating a complex relationship between rTNF binding and biologic response. LT appeared to function like a partial agonist in that rLT was 10- to 20-fold less effective than rTNF in competitively inhibiting 125I-rTNF binding on the II-23.D7 line. Scatchard type analysis revealed a single class of low affinity binding sites for 125I-rLT. No differences in the competitive binding activity of rTNF and rLT were observed on the anti-CD3-activated T cells. Receptors for rTNF and rLT were immunoprecipitated from the II-23.D7 and activated T cells with anticytokine antibodies after cross-linking of radioiodinated rTNF or rLT to intact cells by using chemical cross-linking reagents. Analysis of the cross-linked adducts by SDS-PAGE and autoradiography indicated a major adduct of 92 kDa for rTNF and 104 kDa for rLT. Enzymatic digestion with neuraminidase or V8 protease revealed a unique structure to these adducts consistent with the cross-linking of a single chain of cytokine to a cell surface glycoprotein. rTNF inhibited the formation of the 104-kDa adduct formed with 125I-rLT on the II-23.D7 line, indicating these two cytokines bind to the same receptor of approximately 80 kDa. These results suggest that the disparate activities of LT and TNF to induce MHC class I proteins on the II-23.D7 cells are, in part, associated with a modified state of a common receptor.     

Characterization of the surface topography and putative tertiary structure of the human CD7 molecule

The CD7 gp40 molecule is a member of the Ig gene superfamily and is expressed on T cell precursors before their entry into the thymus during fetal development. N-terminal amino acids 1-107 of CD7 are highly homologous to Ig kappa-L chains whereas the carboxyl-terminal region of the extracellular domain of CD7 is proline-rich and has been postulated to form a stalk from which the Ig domain projects. To define potential functional regions of CD7, we have studied the surface topography of the CD7 Ag by synthesizing peptides corresponding to linear sequences within the CD7 extracellular domains, by raising polyclonal anti-CD7 rabbit sera against these peptides, and by computer analysis of the primary CD7 amino acid sequence. Polyclonal anti-CD7 sera were studied using indirect immunofluorescence, RIA, radioimmunoprecipitation, and Western blot assays. Computer analysis was performed comparing the CD7 sequence with all other known protein sequences. We found that three CD7 epitopes defined by peptides CD7-1A (AA 1-38), CD7-4 (AA 48-74), and CD7-7 (AA 129-146) were available for binding antibody on the surface of the CD7 molecule. Using computer analysis, we transposed the amino acid sequence of the CD7 Ig kappa-like N-terminal domain of CD7 onto the spatial coordinates of REI, a previously reported Ig kappa-molecule highly homologous (48%) to the CD7 N-terminal Ig-like region. Based on computer analysis of this putative CD7 three-dimensional structure, both the CD7-1A and CD7-4 regions protruded from the surface of the N-terminal domain of the CD7 molecule. Finally, comparison of the CD7 transmembrane sequence with CD4 and HIV transmembrane sequences and with respiratory syncytial virus fusion sequences demonstrated similar sequence motifs among these molecules.