bluuebunny/crossref_metadata_2025 huggingface dataset:
Anomalous dispersion of sulfur in quinidine sulfate, (C
20
H
25
N
2
O
2
)
2
SO
4
·2H
2
O: Implications for structure analysis
Authors: Karle Isabella L. , Karle Jerome
Published: May 2006

A Patterson-type map computed with Bijvoet differences squared as coefficients, (ǀ
F
h
ǀ - ǀ
F
-h
ǀ)
2
, as recommended by Rossmann, readily yielded the position of the S atom. The experiment was performed with Cu Kα radiation which is far from the absorption edge for sulfur. The coordinates of the remainder of the 54C, N, and O atoms were derived by means of partial structure development by use of the tangent formula. The latter was used only to effect phase extension, not phase refinement. A main purpose of this experiment was to reaffirm, as first shown in the investigation of the protein crambin by Hendrickson and Teeter, that, in the presence of a large number of lighter atoms, sulfur atoms can be located by use of anomalous dispersion at wave-lengths far from the absorption edge. The space group is P2
1
with
a
= 26.718(8) Å,
b
= 6.987(3) Å,
c
= 10.857(6) Å, and β = 99.51(4)° and contains two quinidyl ions, one sulfate ion, and two water molecules per asymmetric unit. The conformations of the two independent quinidyl ions differ mainly in the torsional angle of the bond between the vinyl side chain and the quinuclidine moiety. The
R
factor is 4.9% for all 2869 data.
Criterion for biholomorphic equivalence of isolated hypersurface singularities
Authors: Mather John N. , Yau Stephen S.-T.
Published: May 2006

Two germs of complex analytic hypersurfaces with isolated singularities are biholomorphically equivalent if and only if they have the same dimension and their moduli algebras are isomorphic.
Existence of nonarithmetic monodromy groups
Authors: Mostow G. D.
Published: May 2006

In an 1885 paper, E. Picard defined a subgroup Τ(Λ) of
PU
(2,1) generated by monodromies and depending on parameters Λ = (λ
1
,λ
2
,λ
3
,λ
4
), 0 < λ

i

< 1, < λ

i

< 3, λ

i

+ λ

j

≥ 1, 1 ≤
i
<
j
≤ 4. The family Τ(Λ) resembles the family of groups Τ([unk]) defined in 1978 but is a different family. In common with the groups Τ([unk]), (
i
) Τ(Λ) is discrete for a finite number of Λ, (
ii
) Τ(Λ) is a nonarithmetic lattice for some Λ, and (
iii
) for all Λ ∈ [unk]
4
, there is a compact complex surface
S
(Λ) with π
1
[
S
(Λ)] of finite index in Τ(Λ).
mRNA in human cells contains sequences complementary to the Alu family of repeated DNA.
Authors: Calabretta B , Robberson D L , Maizel A L , Saunders G F
Published: May 2006

Approximately one-half of the polysomal poly(A)+RNA from CCRF-CEM human lymphoblastoid cells associates at low R0t (10 M.sec) [where R0 is the initial concentration of RNA (M) and t is time (sec)] to form branched complexes detectable by electron microscopy. The complexes typically involve 2-16 molecules associated over double-stranded regions 120 +/- 30 base pairs long. Formation of such complexes suggests that poly(A)+RNA contains repeated-sequence elements that are highly represented in the mRNA population. Hybridization of polysomal poly(A)+RNA with a recombinant human DNA plasmid, p lambda H15C, which is shown to contain at least three regions complementary to two different members of the Alu family of DNA repeat sequences, showed a total of five regions where R loops are formed. The hybridized regions comprising these groups are 260 +/- 180, 240 +/- 170, 150 +/- 70, 180 +/- 60, and 180 +/- 80 base pairs long. The relative frequencies of R loops formed at these different sites indicate that sequences in this recombinant DNA are represented in the mRNA population at different frequencies. The hybridizing sequence of the RNA molecules is located near one terminus in 13% of the R loops and internally in 53% of the R loops. Surprisingly, 35% of the R loops apparently involve RNA molecules hybridized over their entire length of only 200 +/- 110 base pairs.
Rat basophilic leukemia cell lines defective in phospholipid methyltransferase enzymes, Ca2+ influx, and histamine release: reconstitution by hybridization.
Authors: McGivney A , Crews F T , Hirata F , Axelrod J , Siraganian R P
Published: May 2006

Variants of the rat basophilic leukemia (RBL) cell line were isolated and screened for phospholipid methyltransferase I and II activities, enzymes that convert phosphatidylethanolamine to phosphatidylcholine. Two variants were found that had decreased phospholipid methyltransferase enzyme levels and were unable to cause an influx of Ca2+ or release histamine in an IgE-mediated reaction. However, these cells were able to release histamine through an ionophore-induced reaction, indicating that the releasing mechanism distal to the Ca2+ channel was intact. One cell line, 1C1.B1, had low specific activity for phospholipid methyltransferase I. A second variant, 2H3.B6, had reduced phospholipid methyltransferase II activity. Although both variants were unable to incorporate label from [methyl-3H]methionine or [3H]serine into phosphatidylcholine, they were able to incorporate [methyl-3H]choline and myo-[2-3H(N)]inositol into phospholipids. Fusion of the two cell lines and isolation on selective media resulted in the growth of eight independent hybrids. All eight had an increased number of chromosomes and normal phospholipid methyltransferase activities. Stimulation of the hybrids with IgE resulted in CA2+ influx and histamine release. These results indicate that phospholipid methylation precedes and is necessary for Ca2+ influx, and they further support the hypothesis that methylation is a necessary early step in the IgE-mediated histamine release reaction in RBL cells.
Extensive polymorphism in the mitochondrial DNA of apes.
Authors: Ferris S D , Brown W M , Davidson W S , Wilson A C
Published: May 2006

Ape species are 2-10 times more variable than the human species with respect to the nucleotide sequence of mtDNA, even though ape populations have been smaller than the human population for at least 10,000 years. This finding was made by comparing purified mtDNAs from 27 individuals with the aid of 25 restriction endonucleases; for an additional 59 individuals, comparisons were made with fewer enzymes by using the blot hybridization method. The amount of intraspecific sequence divergence was greatest between orangutans of Borneo and Sumatra. Among common chimpanzees, a large component of the variation is due to two highly distinct forms of mtDNA that may reflect a major geographic subdivision. The least amount of sequence variation occurred among lowland gorillas, which exhibit only twice as much sequence variation as humans. The large intraspecific differences among apes, together with the geological and protein evidence, leads us to propose that each ape species is the remnant of an ancient and widespread population that became subdivided geographically and reduced in size and range, perhaps by hominid competition. The low variation among human mtDNAs is consistent with geological evidence that the human species is young. The distribution of site changes within the mitochondrial genome was also examined. Comparison of closely related mtDNAs shows that the ribosomal RNA genes have diverged more slowly than the rest of the genome.
Assembly of the functional membrane attack complex of human complement: formation of disulfide-linked C9 dimers.
Authors: Ware C F , Kolb W P
Published: May 2006

The 158,000 Mr protein, previously designated C5c, present in fully assembled complement (C) membrane attack complexes (MC5b-9) has been identified as a disulfide-bonded dimer of C9. This conclusion was based on the observations that: (i) a portion of the 125I-radiolabeled precursor C9 incorporated into MC5b-9 complexes comigrated with the 158,000 Mr protein band in NaDodSO4/polyacrylamide slab gels; (ii) monospecific antisera produced against native C9 and the 158,000 Mr protein immunologically crossreacted with monomeric native C9 by double immunodiffusion and with monomeric C9 and the 158,000 Mr protein on immunoreplication procedures; and (iii) two-dimensional NaDodSO4/polyacrylamide slab gel electrophoresis, in which the second dimension was conducted under reducing conditions, revealed that the 158,000 Mr protein contained two identical 71,000 Mr subunits which comigrated with monomeric C9. Molar ratio estimates indicated that 1 mol of C5b, C9 dimer, C6, C7, and C8 and 3-4 mol of C9 monomer were present per MC5b-9 complex. Each fully assembled membrane-bound MC5b-9 complex would therefore have a calculated Mr of 982,000. The presence of C9 dimers in the hemolytically active 29S dimeric form of the MC5b-9 complex and the absence of C9 dimers in the hemolytically inactive 23S monomeric form of the fluid phase SC5b-9 complex strongly suggest an important role for C9 dimer formation in MC5b-9 complex structure and function. The most probable function of C9 dimers would be the formation of intercomplex disulfide crosslinks which would provide a mechanism to stabilize the assembly of MC5b-9 into aggregates of increasing size on the target membrane surface which would thus be responsible for the observed pore size heterogeneity of functional C lesions.
Functional helper activity of monoclonal T cell populations: antigen-specific and H-2 restricted cloned T cells provide help for in vitro antibody responses to trinitrophenyl-poly(LTyr,Glu)-poly(DLAla)--poly(LLys).
Authors: Hodes R J , Kimoto M , Hathcock K S , Fathman C G , Singer A
Published: May 2006

The ability of long-term cultured and monoclonal T cell populations to provide antigen-specific help was assessed in a system of Ir gene-controlled in vitro antibody responses to soluble antigens. T-cell colonies and monoclonal T-cell lines were generated which proliferated specifically in response to poly(LTyr,Glu)-poly(DLAla)--poly(LLys) [(T,G)-A--L] and were I-A restricted in these proliferative responses. These (T,G)-A--L-specific T-cell populations were evaluated for their ability to help unprimed and T-cell depleted spleen cell populations in the generation of antibody responses to trinitrophenyl (TNP)-(T,G)-A--L in vitro. It was found that long-term T-cell lines, including monoclonal T-cell populations derived by limiting dilution, were highly efficient helper cells for IgM responses to TNP-(T,G)-A--L. These helper T cells were both antigen-specific and I-A restricted in their ability to be activated and to cooperate with T-cell depleted spleen cell populations. Once specifically activated, however, these clones provided help that was antigen nonspecific. These studies have thus demonstrated the ability of antigen-specific and H-2-restricted monoclonal T-cell populations to provide help for responses to soluble antigens in vitro.
Repression and activation of the genome of herpes simplex viruses in human cells.
Authors: Wigdahl B L , Isom H C , Rapp F
Published: May 2006

We have described previously a cell culture system in which the herpes simplex virus (HSV) type 2 (HSV-2) genome is maintained in a repressed form after treatment of infected cells with 1-beta-D-arabinofuranosylcytosine and increase of incubation temperature from 37 degrees C to 39.5 degrees C. Infectious HSV-2 production was activated by altering incubation temperature or by superinfecting with human cytomegalovirus. We now report the establishment of an analogous system utilizing HSV type 1 (HSV-1). Human embryo lung cells were infected with HSV-1 and treated with 1-beta-D-arabinofuranosylcytosine (25 micrograms/ml) for 7 days to minimize both synthesis of virus DNA and infectious virus while allowing expression of early virus genes. HSV-1 was maintained in an undetectable form for at least 72 days when the incubation temperature was raised from 37 degrees C to 40.5 degrees C after removal of the inhibitor. HSV-1 gene expression was then predictably turned on by superinfection with human cytomegalovirus or by reducing the incubation temperature. Virus replicated after activation was compared with the respective parental virus with regard to inhibition by the HSV-1-specific antiviral (E)-5-(2-bromovinyl)-2'-deoxyuridine and EcoRI, HindIII, and Xba I restriction endonuclease cleavage patterns. The results show activation of HSV gene expression in human cells by a human cytomegalovirus early gene function(s), followed by synthesis of parental-like HSV.
Extendability of proper holomorphic mappings and global analytic hypoellipticity of the ∂̄-Neumann problem
Authors: Bell Steven R.
Published: May 2006

In this communication, the proof of the following theorem is sketched: If
D
1
is a bounded domain in C

n

with real analytic boundary whose ∂̄-Neumann problem is globally real analytic hypoelliptic and
f
is a proper holomorphic mapping of
D
1
onto a second bounded domain
D
2
in C

n

with real analytic boundary, then the mapping
f
extends to be holomorphic in a neighborhood of ¯D
1
. The proof relies on a transformation formula for the Bergman projection under proper holomorphic mappings.
Enzymatic synthesis of biotin-labeled polynucleotides: novel nucleic acid affinity probes.
Authors: Langer P R , Waldrop A A , Ward D C
Published: May 2006

Analogs of dUTP and UTP that contain a biotin molecule covalently bound to the C-5 position of the pyrimidine ring through an allylamine linker arm have been synthesized. These biotin-labeled nucleotides are efficient substrates for a variety of DNA and RNA polymerases in vitro. Polynucleotides containing low levels of biotin substitution (50 molecules or fewer per kilobase) have denaturation, reassociation, and hybridization characteristics similar to those of unsubstituted controls. Biotin-labeled polynucleotides, both single and double-stranded, are selectively and quantitatively retained on avidin-Sepharose, even after extensive washing with 8 M urea, 6 M guanidine hydrochloride, or 99% formamide. In addition, biotin-labeled polynucleotides can be selectively immunoprecipitated in the presence of antibiotin antibody and Staphylococcus aureus protein A. The unique features of biotin-labeled polynucleotides suggest that they will be useful affinity probes for the detection and isolation of specific DNA and RNA sequences.
Dissociation of mitogenesis and late-stage promotion of tumor cell phenotype by phorbol esters: mitogen-resistant variants are sensitive to promotion.
Authors: Colburn N H , Wendel E J , Abruzzo G
Published: May 2006

The JB-6 mouse epidermal cell line has been used as a model system for studying the mechanism of late-stage promoter-dependent preneoplastic progression. The studies reported here are concerned with determining whether there is a requirement for mitogenic stimulation in promotion of anchorage independence and tumorigenicity in JB-6 cells. Such a requirement would predict that variants selected for 12-O-tetradecanoylphorbol 13-acetate (TPA) mitogen resistance would also be promotion resistant. Promotion-responsive cell lines have been selected for resistance to TPA-induced mitogenic stimulation at plateau density by cotreatment with colchicine and removal of mitogen-responsive colchicine-detached cells. The selected TPA-resistant population of cells showed a mitogenic response that was diminished by a factor of four but showed no diminution in the promotion-of-anchorage-independence response to TPA. Mitogen-resistant clonal lines derived from the selected population fell into three phenotypic classes when assayed in soft agar: (i) anchorage-independent transformants; (ii) variants resistant to promotion of anchorage independence by TPA; and (iii) variants sensitive to promotion by TPA. The existence of the latter class (i.e., the mitogen-resistant promotable variants) indicates a lack of obligatory causal relationship between TPa-induced mitogenesis and late-stage promotion and, thereby suggests that the two events can be dissociated.
Murine bone marrow cell line producing colony-stimulating factor.
Authors: Harigaya K , Cronkite E P , Miller M E , Shadduck R K
Published: May 2006

A cell line (H-1) derived from the adherent layer of a 14-wk-old Dexter bone marrow culture has been maintained as cloned and uncloned lines through 21 passages at the time of these studies. These cell lines develop many fat droplets as they age and become confluent. The uncloned line produces increasing amounts of colony-stimulating activity as the cells become confluent. Feeder layers or supernatants from the nonconfluent or confluent fat-laden cells stimulate the formation of greater numbers of colonies derived from cultures of colony-forming units (CFU) than does medium from L cell culture containing colony-stimulating factor (CSF). Antibody to the CSF-containing medium from L cell culture neutralizes the colony-stimulating activity, thus showing immunologic similarity to a known molecular species that stimulates colony production in a CFU culture that produces granulocyte or macrophage populations, or both.
Significance of Lyt phenotypes: Lyt2 antibodies block activities of T cells that recognize class 1 major histocompatibility complex antigens regardless of their function.
Authors: Swain S L
Published: May 2006

The effect of anti-Lyt2 on the generation of helper T-cell function and on cytotoxic effects specific for subregions of the major histocompatibility complex (MHC) was determined. The addition of anti-Lyt2 without complement to in vitro cultures blocked the generation of allogeneic MHC-induced help and lymphokine production and cytotoxic effects when the response was directed against allogeneic class 1 MHC antigens (K and D gene products of the mouse H-2 complex) but had no effect when these responses were specific for class 2 MHC antigens (I region gene products). Anti-Lyt2 failed to block the response of help induced to allogeneic mixed lymphocyte-stimulating determinants or the production of lymphokines by T cells specific for class 1 MHC antigens when concanavalin A lectin was used to induce activity. These and earlier results indicate that the ability of anti-Lyt2 antisera to block function is correlated with T cell specificity for class 1 MHC antigens not with the functional activity of the cells.
H-2 antigen expression on teratocarcinoma cells passaged in genetically resistant mice is regulated by lymphoid cells
Authors: Ostrand-Rosenberg Suzanne , Cohn Allen
Published: May 2006

Previous studies have demonstrated that resistance and susceptibility to the 402AX testicular teratocarcinoma are under genetic control in the mouse. Under normal culture conditions or when passaged in genetically susceptible hosts, the nullipotent 402AX cells do not express H-2 antigens. However, when passaged in genetically resistant animals, the tumor cells become strongly positive for H-2 antigens in the absence of other indications of differentiation. These studies suggested that H-2 antigen modulation on teratocarcinoma cells is mandatory for an effective host cell-mediated immune response against this tumor. The present studies further examine the role of H-2 antigen modulation on teratocarcinoma cells and determine which host cell populations are mediating H-2 modulation on the tumor cells. Reconstitution of lethally irradiated susceptible hosts with resistant bone marrow extends the mean survival time of the host but does not confer complete resistance. Teratocarcinoma cells passaged in such reconstituted hosts do not express H-2 antigens. Two lines of evidence suggest that H-2 antigen modulation is mediated by lymphoid cells: (
i
) sublethal irradiation of genetically resistant hosts inhibits H-2 antigen modulation on teratocarcinoma cells passaged
in vivo
and (
ii
) immunological priming can overcome the loss of H-2 modulation that is normally associated with aging in genetically resistant hosts. Genetically susceptible mice can be fully reconstituted for tumor rejection and H-2 antigen expression on teratocarcinoma cells by reconstitution with genetically resistant bone marrow plus lymphoid cells from tumor-primed resistant hosts. These results: (
i
) imply the necessity for H-2 antigens on tumor cells for an effective host cell-mediated immune response against the tumor, and (
ii
) indicate that host lymphoid cells regulate H-2 antigen expression on tumor cells passaged
in vivo
.
Porcine pituitary dynorphin: complete amino acid sequence of the biologically active heptadecapeptide.
Authors: Goldstein A , Fischli W , Lowney L I , Hunkapiller M , Hood L
Published: May 2006

The full primary structure of the very potent opioid peptide dynorphin, from porcine pituitary, has been determined. It is (H)Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-Trp-Asp-Asn-Gln(OH). The synthetic peptide with this sequence behaves identically to natural dynorphin in a number of ways, and it has the same potency in the guinea pig ileum myenteric plexus--longitudinal muscle bioassay. The potency is accounted for by the first 13 residues.
Hybrid DNA formation during meiotic recombination.
Authors: Hamza H , Haedens V , Mekki-Berrada A , Rossignol J L
Published: May 2006

G234 is a silent mutation located in the middle of gene b2, which controls spore pigmentation in Ascobolus immersus. Its effect on the aberrant segregation patterns of while spore mutants located in the same gene was investigated. When heterozygous, G234 decreases the frequency of aberrant segregations of the mutants located on its right, toward the low conversion end. It almost completely suppresses the aberrant 4:4 asci for mutants giving postmeiotic segregation and decreases the disparity between the 6 wild-type:2 mutant and 2 wild-type:6 mutant aberrant asci for mutants giving only these types of convertant asci. These effects are polar; G234 does not change the aberrant segregation pattern of the mutants located on its left, toward the high conversion end. This behavior suggests that G234 blocks the migration of the symmetric phase of hybrid DNA that diffuses from the high conversion end but does not prevent the formation of asymmetrical hybrid DNA. Taking into account previous observations, we conclude that the high conversion end corresponds to a region of asymmetric initiation of recombination rather than to a region of preferential ending of recombination. The asymmetric hybrid DNA first formed is further changed into a symmetric phase that extends via branch migration toward the low conversion end.
Detection of T cells that secrete molecules which share determinants with antigen-specific T-cell factors.
Authors: Cleveland W L , Wood I , Cone R E , Iverson G M , Rosenstein R W , Gershon R K , Erlanger B F
Published: May 2006

A single-cell secretion assay was used to detect cells that secrete products which react with an antiserum that binds T cell antigen-binding polypeptides. The antiserum (R11), which was produced by immunization of rabbits with a murine trinitrophenyl-specific suppressor factor, reacts with T cells and their products and with a suppressor T-cell clone but not with B cells or their products. The secretory cells this antiserum detected were found to be unevenly distributed among various organs (spleen, lymph node, and thymus) and, to different degrees, in spleens of various strains of mice. In unimmunized CBA/J mice, approximately 1-3% of spleen cells secreted macromolecules precipitable by R11. The majority of the secretory cells could be removed by panning with a mixture of Ly 1 and Ly 2 antibodies but not with either antibody alone. This is consistent with the cells having low surface antigen densities as a result of being either "pre-T" cells or mature secretory cells analogous to B-lineage plasma cells. In agreement with the latter possibility was our finding that the secretory activity of cells detected with antisuppressor factor was comparable to that of Ig-secretory cells as detected with an anti-Ig antiserum. However, higher numbers of R11+ secretory cells were seen in the immunoglobulin-negative fraction of spleen cells from nude mice, which could be interpreted to favor the first possibility. In either case this study shows that the single-cell assay technique is well suited for the detection and characterization of molecules released by immunoregulatory T cells.
Antibody production by single, hapten-specific B lymphocytes: an antigen-driven cloning system free of filler or accessory cells.
Authors: Vaux D L , Pike B L , Nossal G J
Published: May 2006

CBA mouse spleen cells were subjected to hapten affinity fractionation on thin layers of fluorescein (FLU)-gelatin. This procedure yields 97% B cells with varying FLU-binding avidities. One to 30 cells were placed in 10-microliter microcultures without any filler or accessory cells. the T-independent antigen polymerized flagellin coupled to FLU (FLU-POL) was ineffective in stimulating these cells to clonal proliferation or antibody production when used alone. Unpurified preparations rich in interleukins also failed to stimulate the cells. When specific antigen, but not in irrelevant hapten-POL, was combined with the interleukins, clonal proliferation was stimulated and most clones produced anti-FLU antibody-forming cells. The frequency of antibody-forming clones was only slightly lower than that in a system using antigen plus filler cells. In the absence of added interleukins, the mitogens Escherichia coli lipopolysaccharide plus dextran sulfate induced equivalent antibody production. However, a higher frequency of clonal proliferation was noted. Added interleukins did not aid these mitogen-driven responses. Such an antigen-dependent cloning system, free of filler and accessory cells, should permit more precise analysis of the respective roles of antigens and interleukins in the physiology of antibody-forming clone formation.
Increased responses to lymphokines are correlated with preleukemia in mice inoculated with Moloney leukemia virus.
Authors: Lee J C , Ihle J N
Published: May 2006

In various mouse strains, inoculation with Moloney leukemia virus results in the establishment of an acute viremia which in most cases is followed by the induction of leukemia. Also associated with the viremia is the development of a chronic cellular immune response detectable in vitro by the ability of viral proteins to induce splenic lymphocyte proliferation. Previous studies have demonstrated that, in the absence of this cellular immune response, leukemia does not develop irrespective of whether viremia is present [Lee, J. C. & Ihle, J. N. (1981) Nature (London) 289, 407-409]. In vitro proliferative responses to antigens involve the nonspecific response of various subpopulations of lymphocytes to lymphokines produced by antigen-specific Thy 1+, Lyt 1+,2- lymphocytes. The studies presented here concern the effects of a chronic immune response in viremic mice on the frequency of lymphocytes capable of responding to lymphokines in vitro. The data demonstrate that the number of responsive lymphocytes is increased 30- to 100-fold in preleukemic mice and that such increases are dependent upon the induction of an immune response in viremic mice. The role of this altered immune response in leukemia is discussed.
Anti-poly(A) polymerase antibodies in sera of tumor-bearing rats and human cancer patients.
Authors: Stetler D A , Rose K M , Jacob S T
Published: May 2006

Poly(A) polymerase (polynucleotide adenylyltransferase; ATP:polynucleotide adenylyltransferase, EC 2.7.7.19) was covalently linked to diazobenzyloxymethyl-filters and used to screen the sera from a number of tumor-bearing rats and human cancer patients for antibodies to poly(A) polymerase. Sera from rats that had been inoculated with any of several Morris hepatomas or a mammary adenocarcinoma contained immunoglobulins capable of complexing with poly(A) polymerase. No antibodies to the enzyme could be detected in sera from control animals or from those bearing tumors for short periods of time. Antibodies to poly(A) polymerase were also observed in sera from human patients with leukemia, polycythemia vera, and Wilms tumor. The antibodies were not evident in sera from normal volunteers or from patients with nonneoplastic diseases. These included lupus erythematosus, a disorder in which antibodies are produced against an array of nuclear proteins. Immunoglobulins from the serum of one of the human patients were capable of inhibiting poly(A) polymerase activity in vitro, whereas those prepared from the serum of a normal volunteer did not affect enzyme activity. As determined by the diazobenzyloxymethyl-filter technique, the relative concentration of antibodies in the sera of an individual with leukemia (in remission) increased severalfold during a relapse. These data suggest that the presence of antibodies to poly(A) polymerase may be characteristic of sera from cancer patients and that the relative concentration of these antibodies may be indicative of the disease state.
Identification of a variant of mucolipidosis III (pseudo-Hurler polydystrophy): a catalytically active N-acetylglucosaminylphosphotransferase that fails to phosphorylate lysosomal enzymes.
Authors: Varki A P , Reitman M L , Kornfeld S
Published: May 2006

Fibroblasts from patients with I-cell disease (mucolipidosis II) or with pseudo Hurler polydystrophy (mucolipidosis III) are markedly deficient in UDP-N-acetylglucosamine:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase. As a consequence, the common phosphomannosyl recognition marker of acid hydrolases is not regenerated, and these enzymes are not targeted to lysosomes. We have developed a sensitive assay for the transferase that uses alpha-methyl mannoside as an acceptor, and this has allowed us to distinguish between fibroblasts from these two types of patients. The enzyme activity is less in the former than in the latter (less than 0.4-2.0 pmol/mg per hr vs 2.9-39.4). This may provide an explanation for the difference in clinical severity between the two syndromes, However, in two siblings with pseudo Hurler polydystrophy (GM 3392), the enzyme activity was normal when assayed by using alpha-methyl mannoside as acceptor whereas it was low when assayed with endogenous glycoprotein acceptors or with human placental beta-hexosaminidase A. The apparent Km values of the mutant enzyme toward alpha-methyl mannoside, high-mannose oligosaccharides, and UDP-GlcNAc were not different from those of the normal enzyme. Mixing experiments demonstrated that the mutant fibroblasts contained endogenous acceptors and were free of inhibitors. We conclude that the N-acetylglucosaminylphosphotransferase in the mutant fibroblasts has normal catalytic activity but is defective in the ability to recognize lysosomal enzymes as specific substrates for phosphorylation. This variant form of pseudo Hurler polydystrophy demonstrates the biological importance of this recognition mechanism in the generation of the phosphomannosyl marker.
The U3 portion of feline leukemia virus DNA identifies horizontally acquired proviruses in leukemic cats.
Authors: Casey J W , Roach A , Mullins J I , Burck K B , Nicolson M O , Gardner M B , Davidson N
Published: May 2006

The presence and location of DNA sequences related to the U3 and U5 portions of the infectious exogenous feline leukemia virus (FeLV) long terminal repeat (LTR) in various cat DNAs have been determined by hybridization experiments. In uninfected cat DNAs, the U5 LTR segment from the Gardner-Arnstein strain B virus is present at approximately 150 copies per cell. This level is approximately 10-fold greater than that of endogenous internal FeLV sequences. The U5 sequences differ in copy number and, to some extent, in location from one animal to another. For any one animal, the sequence organization of the U5 segments is the same among different tissues, showing that the pattern is inherited through the germ line. Most importantly, the viral U3 LTR probe hybridizes only very weakly with uninfected cat DNAs. Both the U3 and the U5 regions of the LTR from the Gardner-Arnstein strain of virus cross-hybridize with DNA derived from four other infectious FeLVs representing A, B, and C subtypes. Thus, the C3 region may be used as a probe for studying the number and location of exogenously acquired FeLV proviruses in infected cat tissues. In some cases exogenously acquired proviruses are present in unique sites in the genome of virus-positive cat lymphosarcomas, indicating a monoclonal origin for the tumor. In other tumors, the proviral sequences are randomly distributed over many sites. Lymphosarcomas of virus-negative cats have no exogenous U3 sequences despite epidemiological evidence of an association of virus-negative leukemia with exposure to FeLV.
Some calculations on the amount of selfish DNA.
Authors: Ohta T , Kimura M
Published: May 2006

A population genetical theory is developed to treat the amount of selfish DNA in a genome. We assume that the selfish DNA consists of replicating units and that it evolves by multiplication within a genome, exchange between genomes, and random genetic drift at reproduction. Special reference is made to the mean and variance of the number of replicating units per genome in the population. Under the assumption of no systematic evolutionary pressure, the number of units changes randomly with time, and its variance increases by replication process. Although under certain circumstances the variance increases also by exchange process, under ordinary circumstances this process tends to decrease the variance. Random genetic drift also reduces the variance. The relationship between the mean and variance at equilibrium of the number of replicating units per genome in the population was derived. The results obtained will be useful in understanding various observations on repeated DNA which presumably does not contain genetic information and which is likely to be selectively neutral.
Transforming activity of human tumor DNAs.
Authors: Krontiris T G , Cooper G M
Published: May 2006

High molecular weight DNAs of 26 human tumors and tumor cell lines were assayed for the presence of transmissible activated transforming genes by transfection of NIH 3T3 mouse cells. DNAs of two bladder carcinoma cell lines induced transformation with high efficiencies (approximately 0.2 transformant per microgram of DNA), whereas DNAs of the other tumors studied lacked detectable transforming activity. These findings suggest that dominant mutations or gene rearrangements can result in the activation of cellular transforming genes in some human tumors.
A Gauss measure on the set of interval exchange transformations
Authors: Veech William A.
Published: May 2006

An interval exchange transformation is a piece-wise order-preserving isometry of a finite interval. In previous works the author has reduced certain questions about interval exchange transformations to questions about the ergodic behavior of a related class of transformations, with domain the body of all interval exchange transformations. The latter questions can be answered with the aid of Gauss measures for the related transformations; by Gauss measure is understood a conservative, ergodic invariant measure whose density is a rational function. The present note describes the construction of such Gauss measures.
Equipartition of energy for higher-order hyperbolic equations
Authors: Goldstein Jerome A. , Sandefur James T.
Published: May 2006

Let
A
0
,
A
1
,...,
A

2

N

-1

be commuting skew-adjoint operators on a Hilbert space [unk]. Then the equation Π

j
=0

2

N

-1

(
d
/
dt
-

A
j

)
v
(
t
) = 0 (
t
real) admits equipartition of energy [in the sense that the
j
th partial energy

E
j

(
t
) of any solution at time
t
satisfies lim

t
→±∞

E
j

(
t
) = 2

-
N

·(total energy) for each of the 2

N

values of
j
] if and only if the closure

B
jk

of

A
j

-

A
k

satisfies weak-operator-limit exp(

tB
jk

) = 0 as
t
→ ±∞ whenever
j
≠
k
.
Amino acid and carbohydrate structural variants of glycoprotein products (M-N glycoproteins) of the M-N allelic locus.
Authors: Blumenfeld O O , Adamany A M , Puglia K V
Published: May 2006

Major glycoprotein of MgM, MM Miltenberger III (MiIII), and M-N erythrocyte membranes from individual donors were cleaved with CNBr and their amino-terminal octapeptides were examined with respect to amino acid and carbohydrate composition. The amino-terminal octapeptides from the heterozygous MgM donor were resolved into two types, A and A'. MgM A was identical to octapeptide A from MM glycoproteins in carbohydrate and amino acid compositions. MgM A' exhibited amino acid composition similar to NN peptide A except for a single substitution of an Asx for a Thr and, as a result, was not glycosylated. MM(MiIII) octapeptide A was identical to M peptide A in amino acid composition, but differed in carbohydrate content. This glycopeptide contained three O-glycosidically linked carbohydrate units, one of which contained GlcNAc bound to a core of NeuAc, Gal, and GalNAc. About two such units were also present in the CNBr glycopeptide B of the glycoprotein, and on the basis of studies with alkaline borohydride and alkaline sulfite degradations, these units are believed to have the following structure: (formula see text) The Mg is an allelomorph of the M-N locus, likely evolved from a single base substitution in the N gene. The resulting single amino acid substitution effects the posttranslational carbohydration of neighboring Ser and Thr residues. The MM(MiIII) appears to be a product of the M gene that undergoes sequences of posttranslational glycosylations different from those of the M-N glycoproteins.
Covalent modification and repressed transcription of a gene in hepatoma cells.
Authors: Nakhasi H L , Lynch K R , Dolan K P , Unterman R D , Feigelson P
Published: May 2006

When liver cells undergo malignant transformation, certain genes cease being expressed. We have studied the structure of one such gene, whose protein product we have designated hepatic protein 22 (hp22), which is not expressed in the two Morris hepatomas studied. We have prepared a chimeric clone of pBR322 containing cDNA sequences complementary to mRNA coding for this protein. By using this cloned cDNA, we have examined changes in expression of this gene and changes in the restriction pattern of the DNA isolated from normal liver and these hepatomas. In both hepatomas, studies using the isoschizomeric pair of restriction enzymes Msp I and Hpa II have indicated hypermethylation of a cytosine residue within or proximal to the hp22 gene. Other differences in the restriction pattern between normal liver and hepatoma DNA were also detected with EcoRI and Ava I. Thus, in the nontranscribed form of this gene, the DNA has undergone covalent modification, distinguishing these two hepatomas from each other and from normal liver.
Hydrogenative deoxygenation of organic compounds: Direct conversion of amides to alkanes
Authors: van Tamelen Eugene E. , Webber Bruce D.
Published: May 2006

Through the use of (Cp
2
TiH)
x
or (Cp
2
Ti)
1-2
, in which Cp is C
5
H
5
(cyclopentadienyl ligand), it is possible to effect not only the previously known direct reduction of aldehydes and esters to alkanes but also the one-step conversion to alkane of amides derived from selected primary aromatic amines.
Inhibition of ColE1 RNA primer formation by a plasmid-specified small RNA.
Authors: Tomizawa J , Itoh T , Selzer G , Som T
Published: May 2006

Transcription of ColE1 DNA by RNA polymerase in vitro starts at two sites in a region required for maintenance of the plasmid. Certain transcripts that start at one of the sites can be cleaved by RNase H and then act as primers for DNA replication. Transcription from the other site produces a RNA approximately 108 nucleotides long (species I or RNA I). Transcripts analogous to the primer and RNA I of ColE1 are produced when p15A or small derivatives of two other ColE1-compatible plasmids, CloDF13 and RSF1030, are used as template. If purified RNA I is added to the transcription reaction containing RNase H, formation of primer is inhibited. Each RNA I can inhibit primer formation by the plasmid that specifies it but has no effect on primer formation by heterologous templates. Thus, the inhibition of primer formation by RNA I is incompatibility specific. Because RNA I does not inhibit initiation or propagation of transcription or the processing of preformed precursors, the step that is sensitive to inhibition is probably formation of the hybrid between the primer precursor and the template. This hybrid is the required substrate for RNase H. Experiments with recombinant plasmids show the region that determines the specificity of response to RNA I to be greater than 300 base pairs upstream of the origin of DNA replication.
Translational activity and functional stability of human fibroblast beta 1 and beta 2 interferon mRNAs lacking 3'-terminal RNA sequences.
Authors: Soreq H , Sagar A D , Sehgal P B
Published: May 2006

Polyadenylylated mRNA was purified from poly(I).poly(C)- and cycloheximide-superinduced human fibroblast (FS-4) cultures. The mRNA was subjected to electrophoresis through an agarose/CH3HgOH gel, and human fibroblast beta 1 and beta 2 interferon mRNAs were isolated. Each mRNA preparation was phosphorolyzed at 0 degrees C for 20 min by using a molar excess of polynucleotide phosphorylase to produce RNAs lacking poly(A) and then incubated at 37 degrees C for varying lengths of time to allow the phosphorylase to further digest the deadenylylated RNA from the 3' end in a processive and synchronous manner. Removal of the poly(A) (less than or equal to 100 residues) and approximately 100 adjacent residues from human fibroblast beta 1 interferon mRNA (native length, 900 residues, including a 3'-noncoding region of 203 residues) did not alter the translational activity or the functional stability of this mRNA in Xenopus oocytes, whereas deletion of the poly(A) and approximately 200 adjacent residues decreased its translational efficiency. On the other hand, removal of the poly(A) (approximately 200 residues) and approximately 200 adjacent residues from human fibroblast beta 2 interferon mRNA (native length, 1300 residues) did not alter the translational activity or the functional stability of this molecule in oocytes. Thus, neither the poly(A) nor large segments of the 3'-noncoding region (which includes the hexanucleotide A-A-U-A-A-A sequence, at least in the case of beta 1 mRNA) are required for the maintenance of the functional stability of human beta 1 and beta 2 interferon mRNAs in Xenopus oocytes.
Complementation of the plaque-forming cell responses of T-cell-deficient nude mice by a T-cell hybridoma.
Authors: Misfeldt M L , Hanna E E
Published: May 2006

Spleen cells from NFR/N mice primed with carrier rabbit erythrocytes were passed through nylon wool and fused with cells from the AKR T-cell lymphoma BW5147 in order to construct functional T-cell hybridomas. Several hybrids have been obtained. One of the cloned hybrids possesses a marked capacity to functionally complement the T-cell-dependent hapten-specific plaque-forming cell responses of NFR/N nude mice to the trinitrophenyl group. The hybrids carry the Thy 1 marker of the immune parent, express the Lyt 1 surface marker, possess Fc receptors at their surface, and express an Ig heavy-chain variable region determinant at their surfaces as detected by anti-VH MOPC 315 antiserum.
Synthesis of immunoglobulin mu chain gene products precedes synthesis of light chains during B-lymphocyte development.
Authors: Siden E , Alt F W , Shinefeld L , Sato V , Baltimore D
Published: May 2006

Immunoglobulin (Ig) gene expression has been followed during the later stages of development of the murine fetal liver. Biosynthetic labeling and immunoprecipitation were used to isolate Ig-related polypeptides from fetal and neonatal livers. By examination of the specific immune precipitates, the earliest detectable Ig was shown to consist only of mu heavy chain. At about the time of birth, when light chain synthesis became evident, separation of surface Ig-positive cells from surface Ig-negative cells by using anti-Ig-coated dishes showed that cells lacking surface Ig (pre-B lymphocytes) synthesized only mu chains. Thus, commencement of light chain synthesis was closely coordinated with the appearance of surface Ig. Ig RNA species were examined by electrophoretic fractionation and hybridization with cloned Ig DNA sequences. The sizes and amounts of Ig mRNA were found to correlate with the pattern of mu and light chain protein biosynthesis. mu chain RNA species appeared earlier in gestation than light chain RNA did, and only after birth did light chain sequences reach levels equivalent to those of mu chain. Cell populations enriched in pre-B lymphocytes also contained an excess of mu over light chain mRNA.
Molecular rulers for measuring RNA structure: sites of crosslinking in chlorambucilyl-phenylalanyl-tRNAPhe (yeast) and chlorambucilyl-pentadecaprolyl-phenylalanyl-tRNAPhe (yeast) intramolecularly crosslinked in aqueous solution.
Authors: Wickstrom E , Behlen L S , Reuben M A , Ainpour P R
Published: May 2006

Intramolecular crosslinking of yeast phenylalanine tRNA in aqueous solution with rigid, variable-length crosslinking reagents, which we call "molecular rulers," has given results in reasonable agreement with the crystal structure. Chlorambucilyl-[3H]phenylalanyl-tRNAPhe crosslinked intramolecularly at G-71 and A-73, whereas chlorambucilyl-pentadecaprolyl-[3H]phenylalanyl-tRNAPhe crosslinked at G-20 and Y-37. The pentadecaprolyl reagent was predicted to be 62 A long, including chlorambucil and phenylalanine; the sites that it reached are 60 A distant from the 3' OH (in the case of G-20) or 80 A distant (in the case of Y-37) in the crystal structure of tRNAPhe. The close agreement between the length of the reagent and the distance of G-20 from the 3' OH in the crystal structure illustrates the rigidity of the tRNAPhe molecule in the dihydrouridine loop region at the corner of the molecule. The apparent ability of the 62-A-long reagent to crosslink to a site, Y-37, that is 80 A distant from the 3' OH in the crystal structure appears to illustrate the flexibility of both the 3' A-C-C-A terminus and the anticodon stem and loop, with respect to the tRNA molecule. These observations demonstrate the utility of oligoproline-based crosslinking reagents as rigid, variable-length molecular rulers for biological macromolecules in solution.
Prediction of neutral salt elution profiles for affinity chromatography.
Authors: Robinson J B , Strottmann J M , Stellwagen E
Published: May 2006

Neutral salts exhibit very marked differences as eluants of proteins from affinity columns. We observe: (i) that the relative potencies of neutral salts as eluants are independent of the protein or the affinity ligand in the systems studied, (ii) that the absolute salt concentration necessary to elute any given protein bound to the affinity matrix is proportional to the algebraic sum of a set of elution coefficients defined herein for the separate ions present in the solution, and (iii) that the proportionality between elution potency and elution coefficient is a function of the affinity of the protein for the immobilized ligand. Given the concentration of one neutral salt required for elution of a protein of interest from an affinity column, the elution capability of any neutral salt at any temperature can be quantitatively predicted for that protein. Accordingly, application and elution protocols for affinity chromatography can be designed to optimize the yield and fold purification of proteins.