Triangle Singularity as the Origin of the a_{1}(1420)

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.

Serum blood metabolite response and evaluation of select organ weight, histology, and cardiac morphology of beef heifers exposed to a dual corticotropin-releasing hormone and vasopressin challenge following supplementation of zilpaterol hydrochloride

The objectives of this study were 1) to determine if supplementation of zilpaterol hydrochloride (ZH) altered select organ weights, histology, and cardiac anatomical features at harvest and 2) to determine if administration of a corticotropin-releasing hormone (CRH) and vasopressin (VP) challenge following 20 d of ZH supplementation altered the blood chemistry profile in cattle. Crossbred heifers ( = 20; 556 ± 7 kg BW) were randomized into 2 treatment groups: 1) control (CON), without ZH, and 2) zilpaterol (ZIL; ZH at 8.33 mg/kg [DM basis] for 20 d). On d 20 of supplementation, heifers were fitted with indwelling jugular catheters. On d 24, starting at 0800 h and continuing until 1600 h, blood samples were collected at 60-min intervals. At 1000 h, heifers received an i.v. bolus of CRH (0.3 µg/kg BW) and VP (1.0 µg/kg BW) to activate the stress axis. Serum was separated and stored at -80°C until analyzed for a large-animal chemistry panel. Following the CRH/VP challenge, heifers were harvested on d 25, 26, and 27 (5, 6, and 7 d after ZH supplementation); BW, HCW, select organ weights, and histology were measured, and a total heart necropsy was performed. A treatment effect ( ≤ 0.02) was observed for Ca, K, creatinine, alkaline phosphatase, and sorbitol dehydrogenase. Zilpaterol-fed heifers had decreased ( ≤ 0.02) concentrations of Ca and K and increased concentrations ( 0.01) of creatinine ( = 0.02) during the CRH/VP challenge when compared to control heifers. Control heifers had greater ( ≤ 0.05) alkaline phosphatase and sorbitol dehydrogenase concentrations when compared with ZIL heifers. A treatment × time interaction ( = 0.02) was observed for P; concentrations were similar between treatments from -2 to 6 h postchallenge, and 7 h postchallenge CON heifers had decreased P. Liver ( = 0.06) and kidney ( = 0.08) weights as a percentage of BW tended ( ≤ 0.08) to be reduced in ZIL heifers. Gross liver weights tended ( = 0.08) to be lower in ZIL heifers. Other organ (heart, lung, adrenals) to BW ratios remained similar ( ≥ 0.41). These data suggest that there are some variations observed between treatments in terms of response to ZH supplementation and the CRH/VP challenge; however, in the environmental conditions of this study, limited variation in blood metabolic responses and organ weights suggests that the supplementation of ZH did not detrimentally alter the physiology of cattle.

First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190  GeV/c π^{-} beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3  GeV/c^{2} and 8.5  GeV/c^{2}. Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

The genome of the social amoeba Dictyostelium discoideum

The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi.

Closure using a surgical closure device of inadvertent subclavian artery punctures during central venous catheter placement

Severe complications can and do occur when central venous catheters are inadvertently placed into subclavian arteries. Two cases are discussed that describe how these inadvertent arterial punctures can be closed using the Perclose device (Abbott Laboratories, Redwood City, CA, USA).

Interaction between electron transport at the plasma membrane and nitrate uptake by maize (Zea mays L.) roots

In the present study nitrate uptake by maize (Zea mays L.) roots was investigated in the presence or absence of ferricyanide (hexacyanoferrate III) or dicumarol. Nitrate uptake caused an alkalization of the medium. Nitrate uptake of intact maize seedlings was inhibited by ferricyanide while the effect of dicumarol was not very pronounced. Nitrite was not detected in the incubation medium, neither with dicumarol-treated nor with control plants after application of 100 microM nitrate to the incubation solution. In a second set of experiments interactions between nitrate and ferricyanide were investigated in vivo and in vitro. Nitrate (1 or 3 mM) did neither influence ferricyanide reductase activity of intact maize roots nor NADH-ferricyanide oxidoreductase activity of isolated plasma membranes. Nitrate reductase activity of plasma-membrane-enriched fractions was slightly stimulated by 25 microM dicumarol but was not altered by 100 microM dicumarol, while NADH-ferricyanide oxidoreductase activity was inhibited in the presence of dicumarol. These data suggest that plasma-membrane-bound standard-ferricyanide reductase and nitrate reductase activities of maize roots may be different. A possible regulation of nitrate uptake by plasmalemma redox activity, as proposed by other groups, is discussed.

A state-based immunization campaign: the New Mexico experience

Hepatitis B prophylaxis in the form of immunization has become an increasingly effective protective measure across the United States. Various cohorts have been targeted and methodologies used by public health officials to attain optimal coverage of the population. New Mexico is in its third year of school-based hepatitis B immunization programs. New Mexico's approach to this issue is characterized by significant rates of participation (66% in middle schools and 56% in high schools), high vaccination series completion (88% in middle schools and 89% in high schools), and minimal financial investment (cost of vaccine). The "Roll Up Your Sleeves" campaign was piloted, modified, and adapted to New Mexico's multi-lingual and multi-cultural environment, resulting in these successes.

Genetic causes of bull infertility

Infertility and anatomic defects unique to breeding bulls can be influenced by genetics. Veterinarians and animal breeders need to report disorders that may be inherited to a central recording agent, usually the breed association or a veterinary specialist interested in characterizing the disease. Occurrence of these defects is rare, and a large population of animals should be studied to recognize patterns of inheritance early. Numbers of affected animals in a given practice area are often limited, leading to an underestimation of the condition's importance. Genetic defects occur regularly at low frequencies. New syndromes continually arise and most are silently eliminated. Cooperation between cattle breeders, veterinarians, breed associations, and the scientific community is essential in controlling these diseases.

Infection by retroviral vectors outside of their host range in the presence of replication-defective adenovirus

Retrovirus infection is normally limited to cells within a specific host range which express a cognate receptor that is recognized by the product of the env gene. We describe retrovirus infection of cells outside of their normal host range when the infection is performed in the presence of a replication-defective adenovirus (dl312). In the presence of adenovirus, several different ecotropic vectors are shown to infect human cell lines (HeLa and PLC/PRF), and a xenotropic vector is shown to infect murine cells (NIH 3T3). Infectivity is demonstrated by 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal) staining, selection with G418 for neomycin resistance, and PCR identification of the provirus in infected cells. Infectivity is quantitatively dependent upon both the concentration of adenovirus (10(6) to 10(8) PFU/ml) and the concentration of retrovirus. Infection requires the simultaneous presence of adenovirus in the retrovirus infection medium and is not stimulated by preincubation and removal of adenovirus from the cells before retrovirus infection. The presence of adenovirus is shown to enhance the uptake of fluorescently labeled retrovirus particles into cells outside of their normal host range, demonstrating that the adenovirus enhances viral entry into cells in the absence of the recognized cognate receptor. This observation suggests new opportunities for developing safe retroviral vectors for gene therapy and new mechanisms for the pathogenesis of retroviral disease.

Transduction of primary human hepatocytes with amphotropic and xenotropic retroviral vectors

Experiments in animal models suggest that it is feasible to consider hepatic gene therapy using a strategy in which hepatocytes would be isolated by partial hepatectomy, transduced with recombinant retroviral vectors containing genes of therapeutic importance, and then transplanted back into the patient by autologous hepatocellular transplantation. The application of this strategy in clinical trials will require adapting these methods to human cells. We describe the transduction of primary human hepatocytes with two forms of retroviral vectors: amphotropic vectors, which have been used previously in clinical trials, and xenotropic vectors, which have a different host range. Human hepatocytes were harvested from organs preserved in Belzer's solution and were cultivated in a serum-free, tyrosine-free, hormonally defined medium. These cells proliferated for 3-5 days in culture, exhibited characteristic hepatocyte morphology, and expressed liver-specific functions, including phenylalanine hydroxylase, alpha 1-antitrypsin, and glutamine synthase. Transduction with an amphotropic LNL6 retroviral vector resulted in stable incorporation of the provirus into 1% of the cells as estimated by semiquantitative PCR. Consistently higher transduction efficiencies (as much as 10% of the cells) were observed with a xenotropic N2 vector. These data support the feasibility of using LNL6 as a marker gene in clinical trials of hepatocellular transplantation. These data also suggest that the efficiency of transducing hepatocytes with amphotropic vectors in animal models may not accurately reflect the utility of these vectors for human applications. Consideration should be given to the use of xenotropic vectors for optimizing the efficiency of transduction for human applications.

The sequence of a sea urchin muscle actin gene suggests a gene conversion with a cytoskeletal actin gene

We report the nucleotide sequence of the single muscle actin gene of the sea urchin Strongylocentrotus purpuratus. Comparison of the protein-coding sequence of this muscle actin gene (pSpG28) with that of two linked sea urchin cytoskeletal actin genes (pSpG17 and CyIIa) reveals a region of exceptional sequence conservation from codon 61 through codon 120. Furthermore, when silent nucleotide changes are compared, the conservation of this region is still evident (7.9% silent site differences in the conserved region vs 43.3% silent site differences in the rest of the gene when pSpG28 and CyIIa are compared), indicating that the conservation is not due to particularly stringent selection on the portion of the protein encoded by this region of the genes. These observations suggest that a gene conversion has occurred between the muscle actin gene and a cytoskeletal actin gene recently in the evolution of the sea urchin genome. Gene conversion between nonallelic actin genes may thus play a role in maintaining the homogeneity of this highly conserved gene family.

Multiple chromosomal rearrangements in a spontaneously arising t(6;7) rat immunocytoma juxtapose c-myc and immunoglobulin heavy chain sequences

Spontaneously arising immunocytomas in Lou/Wsl rats contain a consistent translocation between chromosomes 6 and 7. The c-myc gene has been localized to chromosome 7 and has been shown to be rearranged in the majority of the rat immunocytomas. We now report the cloning of the rearranged 11-kilobase EcoRI c-myc fragment from the IgE-secreting IR75 tumor. Sequence analysis revealed that the cytogenetically visible t(6;7) translocation must have involved several events in this tumor. One event has led to the juxtaposition of c-myc and the switch mu region, in a head-to-head orientation. The breakpoint is approximately 850 base pairs upstream from the proximal c-myc promoter on chromosome 7. This area is distinct from the more common mouse plasmacytoma- and Burkitt lymphoma-associated translocation breakpoints and also differs from the known murine retroviral insertion sites. A second rearrangement has led to the transposition of sequences upstream from the switch gamma 1 region to the c-myc-distant end of the switch mu region, tail-to-tail. This requires at least two events, including one inversion. In addition to showing that identical loci (c-myc, immunoglobulin) are juxtaposed via chromosomal translocations in three different tumors (Burkitt lymphoma, mouse plasmacytoma, and rat immunocytoma) in different species (human, mouse, and rat), the multiple rearrangements in IR75 and some other tumors emphasize the selective value of c-myc activation by an immunoglobulin locus in the tumorigenic process.

Proviruses are adjacent to c-myc in some murine leukemia virus-induced lymphomas

Sixty-one murine leukemia virus-induced lymphomas were examined for evidence of proviral insertions adjacent to known oncogenes. Five of these lymphomas were found to have alterations adjacent to c-myc. Two of the lymphomas with altered c-myc sequences were examined in detail. Evidence was obtained showing that the alterations in the c-myc sequences in these two lymphomas were the result of proviral integrations. This result suggests that lymphomagenesis by murine leukemia viruses can result from insertional mutagenesis of cellular oncogenes.

DNA methylation affecting the expression of murine leukemia proviruses

The endogenous, vertically transmitted proviral DNAs of the ecotropic murine leukemia virus in AKR embryo fibroblasts were found to be hypermethylated relative to exogenous AKR murine leukemia virus proviral DNAs acquired by infection of the same cells. The hypermethylated state of the endogenous AKR murine leukemia virus proviruses in these cells correlated with the failure to express AKR murine leukemia virus and the lack of infectivity of cellular DNA. Induction of the endogenous AKR murine leukemia virus proviruses with the methylation antagonist 5-azacytidine suggested a causal connection between DNA methylation and provirus expression. Also found to be relatively hypermethylated and noninfectious were three of six Moloney murine leukemia virus proviral DNAs in an unusual clone of infected rat cells. Recombinant DNA clones which derived from a methylated, noninfectious Moloney provirus of this cell line were found to be highly active upon transfection, suggesting that a potentially active proviral genome can be rendered inactive by cellular DNA methylation. In contrast, in vitro methylation with the bacterial methylases MHpaII and MHhaI only slightly reduced the infectivity of the biologically active cloned proviral DNA. Recombinant DNA clones which derived from a second Moloney provirus of this cell line were noninfectious. An in vitro recombination method was utilized in mapping studies to show that this lack of infectivity was governed by mechanisms other than methylation.

Identification of DNA fragments carrying ecotropic proviruses of AKR mice

The proviruses of the N-tropic, ecotropic virus (AKV) of AKR mice (Akv-1, Akv-2) have been studied by the Southern gel--filter transfer technique. These proviruses can be detected by cleavage of cell DNA by BamHI endonuclease, which yields characteristic subgenomic DNA fragments upon cleavage of this type of provirus. Proviruses integrated into different sites in the mouse genome can be resolved with EcoRI endonuclease, which does not cleave the AKV proviruses. Use of congenic and backcrossed mice and a radioactive DNA probe enriched for AKV sequences has allowed identification of the EcoRI fragments carrying the proviruses of the genetically defined Akv-1 and Akv-2 loci. Novel proviruses introduced by superinfection of cultured AKR cells with AKV and present in leukemic cells from AKR mice have also been identified. Comparison of substrains of AKR mice indicates some heterogeneity in their spectra of proviruses.

The integrated genome of murine leukemia virus

The Southern gel filter transfer technique has been used to characterize the integrated genome of Moloney murine leukemia virus (M-MuLV) and the genomes of the endogenous viruses of the mouse. Study of 10 clones of rat cell independently infected by M-MuLV indicates a minimum of 15 integration sites into which the M-MuLV provirus can be inserted. No common integration site is observed among these clones. Clones productively infected by M-MuLV acquire multiple proviruses, whereas infected cells unable to produce virus contain only one M-MuLV provirus. Once established, the integrated genomes are stable for at least two years after initial infection. The use of M-MuLV probe allows detection of a spectrum of Eco RI-cleaved mouse DNA fragments containing endogenous MuLV genomes. DNAs of different inbred laboratory mouse strains yield similar patterns of provirus with each strain showing minor characteristic differences. In some instances, mouse cells infected by M-MuLV reveal additional proviruses beyond those seen in the uninfected cell. DNAs from three different M-MuLV-induced thymomas indicate, as in rat cells, multiple possible integration sites.

Overproducing araC protein with lambda-arabinose transducing phage

Escherichia coli infected with bacteriophage lambda-arabinose transducing phage were tested as sources of araC protein. Infection of cells with such phage produces an intracellular concentration of araC protein up to 100 times that present in wild-type E. coli, apparently resulting from fusion of the araC gene to bacteriophage lambda promoters. Lysates from these phage-infected cells may be fractionated to yield another 100-fold enrichment in araC activity so that the total enrichment is 10,000-fold. A nonsense mutation in araC provided proof of the identification on gel electrophoresis of a band in the purified material. Biologically active araC protein is a dimer with 28,000 M.W. subunits. The araC gene in these phage replaces the int-xis genes but is oriented in the opposite direction. Nonetheless, it appears to be transcribed in this position by the phage promoter pr via transcription the long way around. Furthermore, because araC gene is in this position, we were able to isolate phage on which the araC gene was under phage late gene control by deletion of the late gene transcription stop signals in the b2 region.

In vitro construction of plasmids which result in overproduction of the protein product of the araC gene of Escherichia coli

Derivatives of the Escherichia coli drug resistance plasmid pMB-9 were constructed which contain the promoter from the lactose operon of E. coli fused to the araC gene of E. coli. E. coli possessing these plasmids contain about 50 times as much of the araC gene product as do cells with a wild-type araC gene and promotor.